Wednesday, November 30, 2011

What is the plan Dill and Jem come up with to talk to Boo Radley? Does it work? Why?

Jem and Dill decide to communicate with Boo Radley through a note. Scout goes outside to find them discussing the note, and asks how they plan to get it to him.  Jem explains the plan to Scout:



Jem was merely going to put the note on the end of a fishing pole and stick it through the shutters.  If anyone came along, Dill would ring the bell (To Kill a Mockingbird, Chapter 5).



They had recently noticed a loose shutter.  Their plan is to poke the note through the crack in the shutters and leave it on the window sill inside.  The fishing pole would ensure that neither Dill nor Jem had to set foot on the Radley property to deliver the note.


The note contains questions about Boo Radley and a request for him to come out. They even promise to get him some ice cream if he does. Scout watches Jem try to deliver the note:



Jem attached the note to the end of the fishing pole, let the pole out across the yard and pushed it toward the window he had selected.  The pole lacked several inches of being long enough, and Jem leaned over as far as he could.



Unfortunately, Jem cannot get the note off the end of the pole. When he finally does get the note to detach, it falls down to the ground. Jem makes many attempts to deliver the note, but each time he fails. Scout and Jem hear Dill's bell ringing, and they look to find Atticus coming their way.  They abandon their unsuccessful mission.

Tuesday, November 29, 2011

Is Macbeth responsible for his own fate and should we consider him to be a tragic hero?

Macbeth is a tragic hero because of his unrestrained ambition which leads him to commit many horrible acts. However, he has free will to decide how he wants to lead his own life. Although many factors have an impact on him, including the witches' prophecy and his wife's insistence on murdering Duncan, Macbeth himself is to blame for his own downfall. 


He reveals that his "black and deep desires" are the reason why he wants to pursue his ambition. Those desires are "black" because black symbolizes something that is evil or sinful. And the desires are "deep" because they are secret and hidden from the surface. 


In his soliloquies, Macbeth realizes that murdering king Duncan is wrong on many levels, yet, he chooses to ignore this because of his overwhelming ambition:



I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other.



This ambition, which is his tragic flaw, will lead to his demise. Once he murders Duncan, Macbeth has free will to stop, but he chooses not to. He continues murdering many other innocent people and relying on the witches' prophecy. He stops listening to his wife and begins to plan who else he will eliminate. His unchecked ambition turns him into a cold-blooded murderer, who no longer possesses any sense of right and wrong. 

What is nuclear medicine?


Science and Profession

Nuclear medicine is the branch of medicine that uses radioactive substances in the diagnosis and treatment of diseases. A discussion of such technology requires an understanding of the nature of radioactivity and the tools employed by specialists in this medical field.



Radioactivity is the spontaneous emission of particles from the nucleus of an atom. Several kinds of emissions are possible. Gamma-ray emission is the type with which nuclear medicine imaging is concerned. The activity of radionuclides is measured in terms of the number of atoms disintegrating per unit time. The basic unit of measurement is the curie. Radiopharmaceuticals that are administered are in the microcurie or millicurie range of activity. Most radionuclides used in nuclear medicine are produced from accelerators, reactors, or generators. Accelerators are devices that accelerate charged particles (ions) to bombard a target. Cyclotron-produced radionuclides that are used frequently in nuclear medicine include gallium 67, thallium 201, and indium 111. The core of a nuclear reactor consists of material undergoing nuclear fission. Nuclides of interest in nuclear medicine that are formed from reactors include molybdenum 99, iodine 131, and xenon 133.


In generator systems, a “parent” isotope decays spontaneously to a “daughter” isotope in which the half-life of the parent is longer than that of the daughter. The parent is used to generate a continuous supply of the relatively short-lived daughter radionuclides and is therefore called a generator. The most commonly used generator system is molybdenum 99 (with a half-life of sixty-seven hours) and technetium 99m (with a half-life of six hours). The daughter, technetium 99m, is the most widely used radioisotope in nuclear medicine. It is obtained from the generator in a physiologic sodium chloride solution as the pertechnetate ion. It can be used alone to image the thyroid, salivary glands, or gastric mucosa, or it can be labeled to a wide variety of complexes that are picked up physiologically by various organ systems.


The scintillation camera, or Anger camera (named for its inventor, Hal O. Anger), is the most commonly used static imaging device in nuclear medicine. The scintillation camera produces a picture on a cathode-ray tube of the distribution of an administered radionuclide within the target organ of a patient. It uses the gamma rays emitted by the nuclide and a collimator to create the image as a series of light flashes on a disk-shaped sodium iodide crystal. The system determines the location of each scintillation and then produces a finely focused dot of light on the face of the cathode-ray tube in a corresponding position. The complete picture is then produced on photographic film. The camera normally contains two parts, the head and the computer console. The head serves as the gamma-ray detector. It absorbs incoming gamma rays and generates electrical signals that correspond to the positions where the absorptions took place. These signals are sent to a computer to be processed and to produce a picture that can be displayed on film or stored on disk for video display.


The collimator normally consists of a large piece of lead with many small holes in it. There are many types of collimators. The most commonly used are parallel-hole types. The holes are of equal, constant cross section, and their axes form a set of closely spaced, vertical, parallel lines. The materials between the holes are called septa.


Putting this all together, the radioisotope, once injected or ingested, travels to the target organ. Gamma rays from the target organ are emitted in all directions. The collimator allows only those gamma rays traveling in a direction essentially parallel to the axis of its holes to pass through to the crystal. The crystal is made of sodium iodide, with a small amount of thallium impurity. The thallium is transparent and emits light photons whenever it absorbs a gamma ray. This action by the collimator causes the light flashes in the crystal to form an image of the nuclide distribution located below it. This image will preserve gray-scale information, since the number of gamma rays received by any given region of the crystal will be directly proportional to the amount of nuclide located directly below that region.



Single photon emission computed tomography (SPECT) is a tomographic imaging technique employing scintillation cameras to display the information at a given depth in sharp focus, while blurring information above and below that depth. There are two distinct methods of SPECT, each based on the type of images produced. The first, longitudinal section tomography, provides images of planes parallel to the long axis of the body. The second method, transverse section tomography, is perpendicular to the long axis of the body. Transverse section tomography with a rotating gamma camera has received wide clinical acceptance, partly because of the information that it provides and its multiple-use capability, since these systems can perform routine planar imaging as well as SPECT imaging. In this system, the gamma camera is a device mounted to a gantry and capable of rotating 360 degrees around the patient. These systems must be interfaced with a computer. The orbit around the patient is circular, and from 32 to 180 equiangular images are acquired over a 360-degree arc. Image acquisition is by computer. The images are stored digitally, and image reconstruction is achieved by filtering each projection, with geometric correction for photon attenuation. Noise reduction is generally accomplished by the application of filters. The efficiency of rotating systems can be improved by incorporating additional detectors (most often two or three), which rotate around the patient. Virtually any organ in the body for which an appropriate radiopharmaceutical exists can be studied with SPECT techniques.


No overview of nuclear medicine would be complete without a brief description of positron emission tomography (PET) scanning. Positron-emitting radionuclides, such as carbon 11, nitrogen 13, oxygen 15, and fluorine 8 (a bioisosteric substitution for hydrogen), are isotopes of elements that occur naturally in organic compounds. These tracers enter into the biochemical processes in the body so that blood flow; oxygen, glucose, and free fatty acid metabolism; amino acid transport; pH; and neuroreceptor densities can be measured. A positron is an antimatter electron. This positron-emitting radiopharmaceutical is distributed in a patient’s system. As a positron is emitted, it travels several millimeters in tissue until it meets a free electron and annihilation occurs. Two gamma rays appear and are emitted 180 degrees apart from each other. A scintillation camera could be used to detect these gamma rays, but a collimator is not needed. Instead, the patient is surrounded by a ring of detectors. By electronically coupling opposing detectors to identify the pair of gamma rays simultaneously, the location where the annihilation event must have occurred (the coincidence) can be determined. The raw PET scan consists of a number of coincidence lines. Reconstruction could simply be the drawing of these lines as they would cross and superimpose wherever there is activity in the patient. In practice, the data set is reorganized into projections.




Diagnostic and Treatment Techniques

Nuclear medicine is widely used in the diagnosis and prognosis of coronary artery disease, especially in conjunction with either physical stress testing (treadmill or bicycle exercise) or pharmacological stress testing. The patient is instructed to exercise on the treadmill until his or her heart rate has significantly increased. At peak exercise, a radioisotope, usually thallium 201 or technetium 99m, is injected into a vein. Stress images are obtained. Because the injected tracer corresponds to the blood flow through the arteries that supply oxygen to the heart muscle, those vessels that have a blockage exhibit decreased flow, or decreased tracer delivered to that area of the heart. Rest images are also obtained. Rest and stress images are compared, and differences in the intensity of the tracer, analyzed by a computer, help to identify blocked arteries and the extent of the blockage. This technique is also used in follow-up of patients who have undergone bypass surgery or angioplasty to determine if blockage has recurred.


Nuclear cardiology is also used to measure the ejection fraction (the amount of blood ejected by the left ventricle to all parts of the body) and motion of the heart. Patients with cardiomyopathy, coronary artery disease, or congenital heart disease often have decreased function of the heart. Certain medications used in cancer therapy can also damage the heart muscle. These patients are followed closely to determine if they are developing toxicity from their drug therapy. In these studies, commonly called MUGA scans, a small portion of the patient’s blood is extracted. A radioactive tracer is tagged to this blood, which is then reinjected. The gamma camera takes motion pictures of the beating heart and, through the aid of computers, calculates the ejection fraction.


Nuclear medicine can be very helpful in locating primary or metastatic tumors throughout the body, and it is unique in its ability to assess the viability of a known lesion and its response to radiation or chemotherapy. Breast cancer, lymphomas (especially low-grade), differentiated thyroid cancer, and most sarcomas (both bone and soft tissue) are tumors that will metabolize the appropriate injected radiopharmaceutical. The resulting images will show increased localization in an active tumor but none in those masses that have been destroyed by treatment.


By injecting a radioisotope that has been tagged by bone-seeking agents, doctors can view images of an entire skeleton. Multiple fractures, metastatic disease, osteomyelitis, osteoporosis, and Paget's disease are but a few of the diseases that can be identified quickly and with minimal exposure of the patient to radiation.


Functional as well as anatomical information can be obtained by using nuclear medicine techniques to image the genitourinary tract, especially the kidneys. A perfusion study may be performed as the first phase of structural imaging. This study is done primarily to evaluate the vascularity (amount of blood vessels) of renal (kidney) masses. Cystic lesions and abscesses are usually avascular (having few or no blood vessels), and tumors are usually moderately or highly vascular. Uncommonly occurring arteriovenous (A-V) malformations show high vascularity. An evaluation of blood flow may also be important in patients who have received a kidney transplant. Anatomical renal imaging is performed to evaluate the position, size, and shape of the kidneys. Renal function studies have proven to be very sensitive in the diagnosis of both bilateral and unilateral kidney disease. By following specific tracers through the kidneys, doctors are able to evaluate the filtration by the glomeruli (capillary tufts) and the function of the tubules. Radionuclide cystography (imaging of the bladder), although not performed routinely, is extremely useful in diagnosing vesicoureteral reflux (urine reflux from the bladder back to the ureters), a relatively common problem in children.


Radionuclide imaging plays a significant role in the diagnosis of gastrointestinal disorders. Swallowing function, esophageal transit, gastroesophageal reflux, gastric emptying, gallbladder function, pulmonary aspiration of liver disease, and gastrointestinal bleeding can all be evaluated with nuclear medicine. The application of radioactive materials in the endocrine system provides historical benchmarks in the field of nuclear medicine with the use of radioiodine to assess the dynamic function of the thyroid gland. Radioiodine uptake testing is important and useful in the diagnosis of thyroid disease, specifically hyperthyroidism and hypothyroidism, thyroiditis, and goiters. Thyroid imaging is employed for the detection and functional evaluation of solitary or multiple thyroid nodules and the evaluation of aberrant thyroid tissue, metastases of thyroid cancer, and other tumors containing thyroid tissue.


The therapeutic value of nuclear medicine is best demonstrated in its role in the treatment of Graves disease, toxic adenoma, toxic multinodular goiter, and metastatic thyroid carcinoma. The purpose of the therapeutic application of radioiodine to hyperthyroidism (an overactive thyroid) is to control the disease and return the patient to a normal state. The accumulation and retention of radioiodine, with the subsequent radiation effects upon the thyroid cells, underlie the basic principle behind radionuclide therapy. The treatment of thyroid carcinoma with radioiodine is directed toward the control of metastatic foci and palliation of patients with thyroid carcinoma. Not all thyroid tumors localize radioiodine; therefore, care must be taken for proper patient selection by assuring a tumor’s response to iodine.


Monoclonal antibody imaging has become important not only diagnostically but also therapeutically. Antibodies with perfect specificity for antigens of interest—in this case, malignancies—are produced. These antibodies are labeled with a large dose of radioactivity and injected into the patient. This “magic bullet” is then directed only to the antigen-producing areas. As in thyroid treatment, the radiation effect destroys only those cells to which the radioactivity is attached, leaving the noncancerous cells undamaged. Although this treatment is primarily a research protocol, the future role of radioactive monoclonal antibodies in the treatment of malignant disorders could be significant.


Clinical applications of PET scanning have focused on three areas: cardiology, oncology, and neurology/psychiatry. The principal clinical utility of PET in cardiology lies primarily in accurately differentiating infarcted, scarred tissue from myocardium, which is viable but not contracting because of a reduced blood supply. PET offers a noninvasive procedure to distinguish tissue viability, which allows more accurate patient selection for surgery and angioplasty than conventional approaches. In cancer cases, PET can determine cellular viability and the growth of tumor tissue. It can directly measure the effectiveness of a given radiation or chemotherapy regimen on the metabolic process within the tumor. PET can differentiate tumor regrowth from radiation necrosis.


Because of the unique ability of PET scanning to assess metabolic function, it can aid in the diagnosis of dementia and other psychoses as well as offer possible effective treatment of these disorders. PET is also helpful in detecting the origin of seizures in patients with complex epilepsy and can be used to locate the lesion prior to surgical intervention. Strokes are one of the most common causes of death in the United States. PET can determine the viability of brain tissue after a stroke, permitting the clinician to select the most effective (and least invasive and expensive) form of treatment.


Nuclear imaging techniques are quite safe. Allergic reactions to isotopes are essentially nonexistent. In fact, the few that have been reported can be traced back to a contaminant in the injected dose. The radiation burden is far less than that of fluoroscopic radiographic examination and is equal to that of one chest x-ray, regardless of the picture produced.




Perspective and Prospects

Natural radioactivity was discovered in the late nineteenth century. The first medical success with a radioisotope was Robert Abbe’s treatment of an exophthalmic goiter with radon in 1904. In 1934, the Joliot-Curies produced artificial radioisotopes, specifically phosphorus 32. In 1938, Glenn T. Seaborg synthesized iodine 131. Phosphorus 32 was used to treat chronic leukemia and iodine 131 to treat thyroid cancer. Both treatments fell victim to radiation hysteria fueled by the aftermath of World War II. For a decade, nuclear medicine was equated with the “atomic cocktail” and was used only sporadically as a therapeutic modality. In 1949, the first gamma camera was introduced by Benjamin Cassen. It was called a tap scanner because as it measured radioactivity, it would tap ink on a piece of paper. The intensity of the ink mark was directly proportional to the radioactivity that was being scanned. The first nuclear medicine image was that of a thyroid gland.


Although discovered in the late 1930s, the imaging properties of the short-lived technetium 99m were not understood until the early 1960s. Its six-hour half-life and its chemical properties were ideally suited to imaging with the scintillation camera newly introduced in 1965. From that time on, nuclear medicine grew in its role as a diagnostic tool, with technetium agents becoming the primary radiopharmaceuticals employed in the detection of disease.


With the addition of computers and array processors to the technology, tomographic imaging became increasingly useful in the localization and quantification of disease states. Improved body attenuation correction and computerized three-dimensional imaging enable physicians to quantify the size and extent of abnormalities quite accurately. When one examines the relative role and costs of transmission computed tomography (CT) scanning versus SPECT, a number of factors must be kept in mind. On the side of advantage of SPECT are the low costs compared to CT scanning. Additionally, no contrast is required in the SPECT study, which lessens the chance of adverse patient reaction. CT scanning is still primarily an anatomic diagnostic tool, while SPECT, by employing physiological radiopharmaceuticals, demonstrates the functional features of organs. By repeated imaging during the course of treatment, minute changes in the physiologic biochemical process can be detected and appropriately addressed.


Because of the physiologic nature of nuclear medicine, the development of radiopharmaceuticals to detect other disease states is essential for further growth in this field. It is interesting that much activity in this area is now centered on the treatment of diseases, primarily malignant ones. As PET scanning becomes more frequently used, new positron radiopharmaceuticals will be introduced. Theoretically, all biochemical reactions in the body can be imaged, if the proper radiopharmaceutical is produced.




Bibliography


Brown, G. I. Invisible Rays: A History of Radioactivity. Stroud: Sutton, 2002. Print.



Brucer, Marshall. A Chronology of Nuclear Medicine, 1600–1989. St. Louis: Heritage, 1990. Print.



Christian, Paul E., Donald Bernier, and James K. Langan, eds. Nuclear Medicine and PET: Technology and Techniques. 5th ed. St. Louis: Mosby, 2004. Print.



Gupta, Tapan K. Radiation, Ionization, and Detection in Nuclear Medicine. London: Springer, 2013. Print.



Iskandrian, Ami E., and Mario S. Verani, eds. Nuclear Cardiac Imaging: Principles and Applications. 4th ed. New York: Oxford U P, 2008. Print.



Iturralde, Mario P. Dictionary and Handbook of Nuclear Medicine and Clinical Imaging. 2d ed. Boca Raton, Fla.: CRC, 2002. Print.



Powsner, Rachel A., Matthew R. Palmer, and Edward R. Powsner. Essentials of Nuclear Medicine Physics and Instrumentation. 3d ed. Malden: Wiley-Blackwell, 2013. Print.



Taylor, Andrew, David M. Schuster, and Naomi P. Alazraki. A Clinician’s Guide to Nuclear Medicine. 2d ed. Reston: Society of Nuclear Medicine, 2006. Print.



Ziessman, Harvey, Janis O'Malley, and James Thrall. Nuclear Medicine: The Requisites. 4th ed. Philadelphia: Elsevier, 2014. Print.

Monday, November 28, 2011

What is skin cancer?




Cancer is the common term used to describe the large class
of diseases called neoplasms. Neoplasms, which occur only in multicellular
organisms, develop and function in an autonomous way that does not abide by the
biological mechanisms that govern the growth and apoptosis of
healthy cells. When such neoplasms grow at a rate faster than the tissues from
which they arise, while at the same time invading those tissues, they are called
malignant and are commonly described as cancerous. Benign neoplasms, which do not
invade surrounding tissues, generally are not as dangerous as malignant ones.



Sun radiation is life-sustaining, but the higher-energy spectrum of sunlight
brings the danger of skin damage and skin cancer. When living tissue is
irradiated, its molecular structure is disrupted, thus initiating a chain of
reactions, many of which are not the usual ones associated with the living
organism. Therefore, a change in the chromosomal composition and the development
of unwanted cells is likely to occur. Such changes take place because of the
formation of free
radicals in the deoxyribonucleic acid (DNA) molecules that
constitute the genetic code. The result is skin cancer, one of the most common
forms of cancer in both men and women.



Types of skin cancer. Skin neoplasms may be benign or malignant,
acquired or congenital, although the majority are benign and acquired. The common
mole (the medical term for which is melanocytic nevus) is a
neoplasm of benign melanocytes that is often present at birth and that is known as
a birthmark. Such moles are generally harmless unless they are large in size, in
which case they may have up to a 10 percent chance of becoming malignant. Other
melanocytic nevi are strawberry hemangiomas and port-wine stains, which are of
vascular origin.


The most common form of skin cancer are keratinocyte cancers such as
basal cell
carcinomas and squamous cell carcinomas, which arise
from the main cell type of the epidermis (keratinocytes) and are most often caused
by the cumulative effects of ultraviolet radiation on the skin. They
are generally localized, however, and rarely metastasize. These cancers are easily
identified as persisting sores or crusting patches that grow mostly on sun-exposed
parts of the body such as the hands, neck, arms, and face. They can be treated
with routine surgical procedures.


A malignant melanoma is formed from the pigment-forming melanocyte and
almost certainly undergoes metastasis. It should therefore be removed surgically
at the earliest possible stage. If the melanoma is detected at a later stage,
chemotherapy and irradiation are the techniques usually applied. A malignant
melanoma appears as a lesion that increases in size and turns several colors, such
as black, blue, white, and brown. Symptoms such as itching, bleeding, and pain are
not as common at first but may be encountered at later stages of development.


There are two additional skin malignancies that may be fatal: mycosis
fungoides and Kaposi’s sarcoma. Mycosis fungoides is
a skin lymphoma that may be confined to one location for ten or more years before
it metastasizes to internal organs, when it can become life threatening. As a
result, it is difficult to track this skin cancer, both clinically and
histologically, and several biopsies (skin histological examinations) may be
required to ascertain its presence. On the other hand, Kaposi’s sarcoma occurs
either as lesions (commonly among older Mediterranean men) or as skin
abnormalities in people with human immunodeficiency virus (HIV)
infection. The sarcoma is derived from skin blood vessels and appears as violet
patches or lesions. As long as it is contained only in the skin, it is not fatal.
Once the inner organs are affected, however, it can become life threatening, even
though the lesions may be treated with irradiation and chemotherapy.



The effects of sunlight on skin. Chronic skin exposure to
sunlight leads to the polymerization of skin chemicals (known as catecholamines)
and the subsequent formation of different types of epidermal pigmentation (the
melanins), which are responsible for tanning. Tanning occurs only if there is
gradual exposure to sunlight; otherwise, a sunburn will
arise. Photoprotection is believed to be one of the major biological functions of
the melanin pigment. It appears that melanin formation can participate effectively
in reducing the harmful effects of sunlight by an array of photoinduced chemical
reactions, which result in the consumption of scavenging active oxygen species
such as the superoxide anion and hydrogen peroxide. It has been determined that in
biological systems, superoxide and hydrogen peroxide are formed in small
quantities during normal processes. Both species are known to produce several
biological effects, most of which are harmful to tissues. It should be pointed
out, however, that although melanin may act as a free radical scavenger, it may
also become energetically overloaded and may change to a toxic state. Evidence
exists that melanin increases the radiative damage to cells, which leads to
sunlight-induced skin cancer. In other words, melanin formation is good only when
moderate exposure to sunlight occurs.


In the atmosphere twelve to forty-eight kilometers above the earth’s surface lies
a small layer of ozone. Although this layer does not contain much ozone—it is
estimated to be about three millimeters thick under normal conditions of
temperature and pressure—it has a profound effect on life. The ozone layer absorbs
the harmful ultraviolet radiation from the sun, thus providing the mechanism for
the heating of the stratosphere. A reduction in the ozone layer would lead to a
large increase of ultraviolet rays intruding into the atmosphere, thus increasing
the incidence of skin cancer. F. S. Rowland and M. J. Molina declared in
1974 that the presence of the volatile chlorofluorocarbons would eventually reduce the ozone layer.
Some measurements done by scientists in 1979 showed a decrease in the layer, which
led to the action taken by several governments to decrease and replace the
chlorofluorocarbons commonly used in aerosols. The coordinated international
action has slowed the depletion of the ozone layer, although significant thinning
occurred over the Antarctic. The highest incidence of melanoma worldwide is
reported in Australia. As the average life span of humans steadily increases, the
incidence of skin cancer will likely increase as well; however, education about
skin cancer prevention will hopefully reduce the number of cases and improved
diagnosis and treatments have increased survival rates. Sunscreens with sun
protecting factor (SPF) of at least 30 and hats and sunglasses with high
ultraviolet blocking are recommended for people who are exposed to large amounts
of sunlight, particularly those with fair skin who are at a higher risk of
developing skin cancer due to sun damage.




Bibliography


Baldi, Alfonso, Paola Pasquali, and Enrico
P. Spugnini, eds. Skin Cancer: A Practical Approach. New
York, Humana, 2013. Print.



Cognetta, Armand B., Jr., and William M.
Mendenhall, eds. Radiation Therapy for Skin Cancer. New
York: Springer, 2013. Print.



Dollinger, Malin, et
al. Everyone’s Guide to Cancer Therapy. 5th ed. Kansas
City: McMeel, 2008. Print.



Dummer, Reinhard, et al., eds.
Skin Cancer—A World-Wide Perspective. New York:
Springer, 2011. Print.



James, William D., et
al. Andrews’ Diseases of the Skin: Clinical Dermatology.
11th ed. Philadelphia: Saunders/Elsevier, 2011. Print.



McClay, Edward F., and
Jodie Smith. One Hundred Questions and Answers About Melanoma and
Other Skin Cancers
. Boston: Jones and Bartlett, 2004.
Print.



"Skin Cancer Facts." American Cancer
Society
. American Cancer Society, 19 Mar. 2014. Web. 15 Sept.
2014.



Siegel, Mary-Ellen.
Safe in the Sun. Rev. ed. New York: Walker, 1995.
Print.



Weedon, David.
Skin Pathology. 3rd ed. New York: Elsevier, 2010.
Print.

Sunday, November 27, 2011

What is multiple endocrine neoplasia type 1 (MEN 1)?





Related conditions:

Hyperparathyroidism, pituitary tumor, pancreatic tumor, duodenal tumor





Definition:
Multiple endocrine neoplasia type 1 (MEN 1) is a hereditary tumor syndrome characterized by endocrine and nonendocrine tumors, most of which are benign. The characteristic findings include tumors of the parathyroid glands, pituitary gland, pancreas, and duodenum (part of the small intestine). Neuroendocrine tumors (nerve-cell tumors that may produce hormones) in the pancreas and duodenum are the main cause of tumor-related death. The severity varies within families and between families.



Risk factors: Because MEN 1 is hereditary, the main risk factor is having a family history of this disorder. Each child of a person with MEN 1 has a 50 percent chance of inheriting the disorder.



Etiology and the disease process: The underlying genetic cause of MEN 1 is a mutation, or a genetic change, in the MEN1 gene. MEN1 is a tumor-suppressor gene, and the protein it encodes helps stop uncontrolled cell growth and proliferation.


Usually, each person has two normal copies of the MEN1 gene. A mutation in one copy of the gene is sufficient to cause MEN 1, which is why this condition is referred to as autosomal dominant (autosomal means the MEN1 gene is located on one of the twenty-two pairs of autosomes, which are the nonsex chromosomes). An affected person has a MEN1 gene mutation from the time of conception in the womb; however, symptoms of the disease may not manifest until later in life. Most mutations are inherited from a parent, but new mutations do occur.



Incidence: According to the US National Library of Medicine's Genetics Home Reference in 2014, approximately 1 per 30,000 people have MEN 1.



Symptoms: Parathyroid tumors can cause high calcium levels in the blood, nausea, fatigue, muscle pains, constipation, abdominal pain, kidney stones, and bone fractures. Symptoms of pituitary tumors vary depending on the type of hormone being made by the tumor. Tumors of the pancreas and duodenum cause many different symptoms depending on the tumor type.



Screening and diagnosis: Physicians diagnose MEN 1 in a person with an endocrine tumor in two of the three tissue systems usually affected in this syndrome: parathyroid glands, pancreas, and pituitary gland. Because MEN 1 is caused by mutations in the MEN1 gene, genetic testing can be used to confirm a suspected diagnosis or to test a family member who is at risk for the disease but has no symptoms.



Treatment and therapy: A combination of surgery and medication may be used to treat MEN 1 tumors.



Prognosis, prevention, and outcomes: Because MEN 1 is a genetic condition, its manifestations cannot currently be prevented. However, physicians recommend monitoring that includes blood testing for hormone levels and imaging of the head and abdomen.



Amer. Soc. of Clinical Oncology. "Multiple Endocrine Neoplasia Type 1." Cancer.Net. ASCO, May 2014. Web. 13 Nov. 2014.


Chen, Yi-Bin. "Multiple Endocrine Neoplasia (MEN) I." MedlinePlus. US NLM/NIH, 23 Mar. 2014. Web. 13 Nov. 2014.


Genetics Home Reference. "MEN1." Genetics Home Reference. US NLM, 11 Nov. 2014. Web. 13 Nov. 2014.


Genetics Home Reference. "Multiple Endocrine Neoplasia." Genetics Home Reference. US NLM, 11 Nov. 2014. Web. 13 Nov. 2014.


Giusti, Francesca, Francesca Marini, and Maria Luisa Brandi. "Multiple Endocrine Neoplasia Type 1." GeneReviews. NCBI/NLM/NIH, 6 Sept. 2012. Web. 13 Nov. 2014.


MedlinePlus. "Endocrine Diseases." MedlinePlus. US NLM/NIH, 9 Aug. 2014. Web. 13 Nov. 2014.


Natl. Endocrine and Metabolic Diseases Information Service. "Multiple Endocrine Neoplasia Type 1." Natl. Endocrine and Metabolic Diseases Information Service. Natl. Inst. of Diabetes and Digestive and Kidney Diseases, NIH, 6 Apr. 2012. Web. 13 Nov. 2014.

What is the message of the story "If I Forget Thee, O Earth . . ."?

The story shows the earth as uninhabitable. A nuclear war has led to the annihilation of life on the planet. Even from the moon, the earth can be seen “gleaming faintly with an evil phosphorescence.”


The few human survivors have taken refuge on the moon. They will have to stay on the lunar surface for hundreds of years until the effect of the toxic nuclear radiation dies down.



 “The winds and the rains would scour the poisons from the burning lands and carry them to the sea, and in the depths of the sea they would waste their venom until they could harm no living things. Then the great ships that were still waiting here on the silent, dusty plains could lift once more into space, along the road that led to home.”



The story was first published in 1951 during the early years of the Cold War. It reflects the prevailing apprehensions over the possibility of a nuclear war between the two superpowers, the United States and the Soviet Union, and their allies. After the Second World War, both the superpowers began manufacturing nuclear warheads at an unprecedented scale.


In his story, the author Arthur C. Clarke presents a horrifying picture of the earth. It burns day and night on its “funeral pyre." With this story, he sent a very strong message to world leaders. Through his terrifying portrayal of the earth in the aftermath of a possible nuclear war, he warned against the production and use of nuclear warheads.


The lesson is clear. The story strongly discourages applying science and technology to produce weapons of mass destruction. It urges us to work together as the guardians of this unique planet and do all that is possible to preserve its resources. Instead of engaging in a nuclear arms race, every country should sincerely endeavor to keep our planet safe, clean and beautiful.


Though the Cold War has ended, the story is still very relevant. The production of nuclear warheads hasn’t stopped yet. The list of countries considered nuclear powers has been growing. The danger of war looms large across the globe. There are also environmental concerns regarding the safety of the earth. The insensitive exploitation of natural resources and the emission of greenhouse gases threaten the safety of the planet.


The story presents an artistic imagining of a ruined earth. It exhorts us to grow concerned and sensitive towards our planet before it is too late.

Saturday, November 26, 2011

Some salt, vegetables and spices are added to some hot water. The salt disappears into the water, the vegetables sink to the bottom and the spices...

A solution is a homogeneous mixture of substances, meaning that the substances are evenly distributed. It consists of two types of components, a solvent and one or more solutes. The solute is dissolved in the solvent. The solvent is usually present in a greater amount.


In this mixture salt is a solute. It doesn't actually disappear; it becomes invisible on a macroscopic level when it dissolves. Since it's observed to dissolve we can assume that it becomes evenly distributed. 


Water is behaving as a solvent, dissolving the salt. The phase of a solution, which is liquid in this case, is that of the solvent.


The spices and vegetables don't dissolve and aren't part of the salt water solution. This is actually a mixture within a mixture. The overall mixture is heterogeneous with one of its components, salt water, being a solution.

What is frontotemporal dementia (FTD)?


Causes and Symptoms

Frontotemporal dementias
(FTDs) are a group of disorders characterized by degeneration of the frontal and temporal lobes of the brain. These areas in the brain are responsible for language, behavior, and personality. Magnetic resonance imaging (MRI) of the brain can show shrinkage of the brain in these areas (frontal and/or temporal lobes). FTDs can show variable symptoms depending on which parts of the brain may be affected. Most individuals have either behavior changes or language disturbances as their main feature.



Behavior changes associated with FTDs include dramatic personality changes, toward either impulsive and disinhibited or apathetic and listless. Frequently, verbal and facial social cues are unrecognizable to affected individuals. Additional behaviors can include isolation, lack of empathy and sympathy, distractibility, loss of insight, dietary changes (sweet food preferences), neglect of personal hygiene, repetitive behaviors, and decreased motivation. Language changes in FTDs are of two main types: loss of ability to speak as a result of difficulty with word recall (primary progressive aphasia) or loss of ability to understand language (semantic dementia).


Frequently, family members bring affected individuals to medical attention because of these behavioral changes, which go unrecognized to the individual. The onset of FTD can be from age forty to seventy; therefore, individuals can be living with the disease many years before family members notice personality and behavior changes or behaviors begin to interfere with activities of daily living.


There are a few rare types of FTDs that involve movement disorders in addition to dementia. One type is FTD with motor neuron disease (MND). Classical MND is also called amyotrophic lateral sclerosis
(ALS) or Lou Gehrig’s disease. FTD can also be seen with symptoms of Parkinson’s disease. Movement disorder-related symptoms can include tremor, weakness, difficulty swallowing, and poor coordination.


People can be misdiagnosed with psychiatric problems, especially with the young age of onset seen in FTDs. Others can be misdiagnosed with Alzheimer’s disease because of the fact that it is much more commonly seen by physicians.


Men and women are affected equally by FTD. Family history is the greatest risk factor for FTDs, with approximately 50 percent of all FTD cases showing familial inheritance. Mutations in several genes have been shown to cause several types of FTDs. Genetic testing may be offered. Individuals with FTD symptoms will undergo a variety of tests to try to rule out other illnesses that may mimic the symptoms of FTD. These tests may include blood count, electrolytes, liver function, thyroid function, and kidney function. Also, images of the brain via magnetic resonance imaging (MRI) and computed tomography (CT) scanning may be obtained to rule out bleeding or tumors that can cause similar symptoms. Finally, neuropsychological testing may be used to help determine if there are language, memory, and/or reasoning deficits to aid in the diagnosis of FTD.




Treatment and Therapy

FTD is a degenerative disorder. There are no treatments to cure or slow the progression of the brain degeneration. The median duration of illness is six to eight years from onset to death, although the length of time can range from less than two years to more than ten years. Individuals with FTD-MND have a shorter survival time, with a median survival of only three years. Most therapy for individuals with FTDs focuses on managing the symptoms and behaviors seen in the disorder. Speech therapy can be helpful to learn new strategies to aid in verbal and written communication. Caregivers can help reduce behavior problems by avoiding behavior triggers (events or activities), anticipating needs, and maintaining a calm environment. Caregivers should focus on building a support network that includes social services, psychiatric care, support groups, respite care in adult care centers, and/or home health aids. Ultimately, individuals with FTDs will progress to require twenty-four-hour care, and nursing home care may be required. Many patients, if able, may wish to help family members with this planning ahead of time, making the transition for caregivers and family members easier knowing that the affected individual was part of the decision-making process.


Medications currently used to treat the behavioral symptoms of FTD include antidepressants and antipsychotics. These drugs have not shown great success. Therapeutic research related to the genetic causes of FTDs, however, has shown promise. For example, the microtubule-associated protein tau (MAPT) gene can be altered to cause toxic clumps and tangles of MAPT protein. These MAPT tangles are seen in several forms of FTDs. Therapies and drugs designed to prevent or fix the MAPT tangles are currently being designed and tested in animal models. Additional testing and validation will be needed before clinical trials begin in humans.




Perspective and Prospects

FTD was originally described by Arnold Pick in the 1890s. He published a case series of patients in which he described the behavioral and language variants now part of the clinical criteria of FTD. In 1926, two neuropathologists, K. Onari and Hugo Spatz, described the brain findings commonly seen in FTD, including shrinkage of the frontal and temporal lobes and Pick bodies. In the 1980s, the term “frontolobe dementia” and “frontotemporal dementia” were derived in a group of papers trying to define the clinical criteria of FTD and help differentiate the disorder from Alzheimer’s disease. The recent discovery of several mutated genes that can cause FTD symptoms has helped physicians and scientists define the disorder and will only lead to improved diagnosis and treatments for the future.




Bibliography:


Bradley, Walter, et al., eds. Neurology in Clinical Practice. 6th ed. Boston: Butterworth Heinemann, 2012.



Cairns, Nigel J., et al. “Neuropathologic Diagnostic and Nosologic Criteria for Frontotemporal Lobar Degeneration: Consensus for the Consortium for Frontotemporal Lobar Degeneration.” Acta Neuropathologica 114 (2007): 5–22.



Carson-DeWitt, Rosalyn, and Rimas Lukas. "Dementia." Health Library, Sept. 27, 2012.



"Dementia." MedlinePlus, May 7, 2013.



"Frontotemporal Disorders: Information for Patients, Families, and Caregivers." National Institute on Aging, Mar. 13, 2013.



Kertesz, Andrew. “Frontotemporal Dementia/Pick’s Disease.” Archives of Neurology 61 (2004): 969–971.



"MAPT." Genetics Home Reference, May 13, 2013.



Neary, David, Julie Snowden, and David Mann. “Frontotemporal Dementia.” The Lancet Neurology 4 (2005): 771–780.



"NINDS Frontotemporal Dementia Information Page." National Institute of Neurological Disorders and Stroke, Mar. 20, 2013.

What is emphysema?


Causes and Symptoms

Emphysema is a lung disease in which damage to the lungs causes shortness of
breath and can lead to heart or respiratory failure. A discussion of the structure
and function of the normal lung can illuminate the nature and effects of this
damage.



Air—along with gases, smoke, germs, allergens, and environmental pollutants—passes
from the nose and mouth into a large duct called the trachea. The
trachea branches into smaller ducts, the bronchi and
bronchioles (small branches of the bronchi), which lead to tiny air sacs called
alveoli. The respiratory system is like an upside-down tree: The trachea is the
trunk, the bronchi and bronchioles are similar to the branches, and the alveoli
are similar to the leaves. The blood vessels of the alveoli carry red blood cells,
which pick up oxygen and transport it to the rest of the body. The cellular waste
product, carbon dioxide, is released to the alveoli from the bloodstream and then
exhaled. The alveoli are supported by a framework of delicate elastic fibers and
give the lung a very distensible quality and the ability to “snap back,” or
recoil.


The lungs and bronchial tubes are surrounded by the chest wall, composed of bone
and muscle and functioning like a bellows. The lung is elastic and passively
increases in size to fill the chest space during inspiration and decreases in size
during expiration. As the lung (including the alveoli) enlarges, air from the
environment flows in to fill this space. During exhalation, the muscles relax, the
elasticity of the lung returns it to a normal size, and the air is pushed out. Air
must pass through the bronchial tree to the alveoli before oxygen can reach the
bloodstream and carbon dioxide can get out, because it is the alveoli that are in
contact with blood vessels. The bronchial tree has two kinds of special lining
cells. The first type can secrete mucus as a sticky protection against injury and
irritation. The second type of cell is covered with fine, hairlike structures
called cilia. These cells are supported by smooth muscle cells and elastic and
collagen fibers. The cilia wave in the direction of the mouth and act as a defense
system by physically removing germs and irritating substances. The cilia are
covered with mucus, which helps to trap irritants and germs.


When alveoli are exposed to irritants such as cigarette smoke, they produce a
defensive cell called an alveolar macrophage. These cells engulf irritants and
bacteria and call for white blood cells, which aid in the defense against foreign
bodies, to come into the lungs. The lung tissue itself also becomes a target for
the enzymes or chemical substances produced by the alveolar macrophages and
leukocytes (white blood cells). The enzymes vigorously attack the elastin and
collagen of the lungs, the lung alveoli lose their elastic recoil, and air is
trapped, making exhalation difficult.


Emphysema and a related disease, chronic bronchitis, in which the
airways of the long become chronically inflamed, often work in concert. They are
grouped together under the term chronic obstructive pulmonary disease
(COPD). Chronic bronchitis weakens and narrows the bronchi. Often, bronchial walls
collapse, choking off the vital flow of air. Air is also trapped within the
bronchial walls. Weakened by enzymes, the walls of the alveoli rupture and blood
vessels die. Lung tissue is replaced with scar tissue, leaving areas of destroyed
alveoli that appear as “holes” on an X-ray. Small areas of destroyed alveoli are
called blebs, and larger ones are called bullae.


As emphysema progresses, the patient develops a set of large, overexpanded lungs
with a weakened and partially plugged bronchial tree subject to airway collapse
and air trapping with blebs and bullae. Breathing, especially exhalation, becomes
a slow and difficult process. The patient often develops a barrel chest. The
scientific world calls the mismatching of breathing to blood distribution a
ventilation-to-perfusion imbalance; that is, when air arrives in the alveolus,
there are no blood vessels there to transport the vital gaseous cargo to the cells
(as a result of enzymatic damage). A person with COPD has a bronchial tree with a
narrow, defective trunk (chronic bronchitis) and sparse leaves (emphysema).


The loss of elasticity of the lung and alveoli is a critical problem in the
patient with emphysema. About one-half of the lungs’ elastic recoil force comes
from surface tension. The other half comes from the elastic nature of certain
fibers throughout the lungs’ structure. Emphysema weakens both of these forces
because it destroys the elastic fibers and interferes with the surface tension.
Fluid, a saline solution, bathes all the body’s cells and surfaces. In the lung,
this fluid contains a surfactant, a substance that interferes with water’s
tendency to form a spherical drop with a pull into its center (and ultimate
collapse). The tissue that gives shape to the lungs is composed of specialized
fibers that contain a protein called elastin. These elastic fibers are also found
in the alveolar walls and in the elastic connective tissue of the airways and air
sacs. The amount of elastin in lung tissue determines its behavior. Healthy lungs
maintain a proper balance between destruction of elastin and renewal. (Other parts
of the body, such as bones, do this as well.) If too little elastin is destroyed,
the lungs have difficulty expanding. If too much is destroyed, the lungs
overexpand and cannot recoil properly.


The process of elastin destruction and renewal involves complex regulation.
Specialized lung cells produce new elastin protein. Others produce elastase, an
enzyme that destroys elastin. The liver plays a role in the production of a
special enzyme known as alpha-1-antitrypsin, which controls the amount of elastase
so that too much elastin is not digested. In emphysema, these regulatory systems
fail: Too much elastin is destroyed because elastase production is no longer
controlled, apparently because alpha-1-antitrypsin production has been reduced to
a trickle. In some persons, alpha-1-antitrypsin deficiency is an
inherited condition.


The loss of elastin (and thus elastic recoil) means that the lungs expand beyond
the normal range during inspiration and cannot resume their resting size during
expiration. Thus, alveoli overinflate and rupture. This further reduces
elasticity, because the loss of each alveolus further impairs the surface tension
contribution to the lungs’ ability to recoil. Thus, a state of hyperinflation is
assumed in the patient with emphysema. This leads to stretched and narrowed
alveolar capillaries, loss of elastic tissue, and dissolution of alveolar walls.
The lungs increase in size, the thoracic (chest) cage assumes the inspiratory
position, and the diaphragm becomes low and flat instead of convex. The patient
becomes short of breath with any type of exertion. As the disease worsens, the
patient’s skin takes on a cyanotic (bluish) color as a result of poor oxygenation
and perfusion. Wheezing is often present, and coughing is difficult and
tiring. In the worst cases, even talking is enough exertion to produce a spasmodic
cough. The hyperinflated chest causes inspiration to become a major effort, and
the entire chest cage lifts up, resulting in considerable strain.


Emphysema may be diagnosed by the early symptom of dyspnea (shortness of breath)
on exertion. In advanced cases, the distended chest, depressed diaphragm,
increased blood carbon dioxide content, and severe dyspnea clearly point to the
disease.




Treatment and Therapy

The initial step in treating emphysema is to eliminate the causes of irritation:
smoke, polluted air, infection, and allergies. For smokers, smoking
cessation is critical, and bupropion may
be prescribed to help with smoking cessation. To improve dyspnea and the patient's
quality of life, pulmonary rehabilitation may be part of the treatment process,
including exercise training, nutrition counseling, and patient education. Exercise
training may include exercises to strengthen the chest muscles as well as
breathing techniques to improve air flow into the lungs.


A number of medications are useful in the treatment of emphysema, although no
medications have been shown to modify the long-term decline in lung function seen
in patients with emphysema or COPD. Instead, medications are used to decrease
symptoms and reduce complications. Bronchodilator drugs relieve bronchospasms,
reduce wheezing and dyspnea, and improve respiratory muscle function. Categories
of bronchodilators include the beta-2 agonists, which may be short-acting or
long-acting, and inhaled anticholinergics. Examples of short-acting beta-2
agonists include albuterol, terbutaline, fenoterol, and levalbuterol. Among the
long-acting beta-agonists are arformoterol and formoterol. Some side effects of
beta-agonists include nervousness, headache, nausea, and muscle cramps. Inhaled
corticosteroids may also be used in the treatment of emphysema; however, the
long-term use of corticosteroids may increase the risk of pneumonia.



Antibiotics are sometimes prescribed for patients with
emphysema to combat bacterial infections that can
dramatically worsen the effects of their condition. Furthermore, the
influenza
vaccine and pneumococcal polysaccharide vaccine are
strongly recommended to reduce serious illness and complications.


Sometimes emphysema patients are given supplemental oxygen, also called
oxygen
therapy, if their lung function is too impaired to keep the
oxygen levels in their blood sufficiently high. Portable oxygen tanks that deliver
oxygen through a tube and a mask can give patients greater mobility to carry out
tasks of daily living. In rare cases, surgery is an option for severe cases of
emphysema. The two kinds of surgery available are lung volume reduction surgery
(LVRS) and, as a last resort, a lung transplant. The aim of LVRS is to remove the
most diseased portions of the lung to give the healthier portion more room to
function. A lung transplant may be considered if a patient's lungs are in danger
of failing entirely and if the patient is determined to be strong enough to endure
the procedure and the recovery period.


Individuals with emphysema should avoid both excessive heat and excessive cold. If
body temperature rises above normal, the heart works faster, as do the lungs.
Excessive cold stresses the body to maintain its normal temperature. Smog, air
pollution, dusts, powders, and hairspray should be avoided. Finally, a healthy
diet consisting of foods high in calcium, vitamins, complex carbohydrates,
proteins, and fiber is advised for the patient with lung disease. Caloric
supplementation may improve exercise capacity in patients with COPD, especially
undernourished patients.




Perspective and Prospects

According to the US Centers for Disease Control and Prevention, chronic lower
respiratory diseases (primarily COPD) were the third leading cause of death in the
United States in 2011. The World Health Organization reported in 2014 that COPD
was also the third leading cause of death worldwide, accounting for 3.1 million
deaths in 2012. Although the death rates from COPD have declined slightly among
men from 1999 to 2010, they have stayed about the same for women, and the overall
average has barely changed. Aside from death, a disease such as emphysema can
cause long years of disability, joblessness, loss of income, depression,
hospitalization, and an inability to perform normal activities.


Smoking is, by far, the single most important risk factor for emphysema. The
prevalence of COPD among smokers is estimated to be approximately 15 percent.
Socioeconomic status also influences rates of COPD, with lower-income workers
experiencing higher rates of the disease. COPD also correlates negatively with
level of education: The rate in 2011 among those without a high school diploma was
9.5 percent; 6.8 percent among those with a high school diploma; and 4.6 percent
among those with some college. The prevalence of COPD also increases with age.


A number of economic pressures are likely to move COPD treatment from the hospital
to the home. When effectively carried out by a well-trained health team, home care
can lower medical costs. The COPD patient who finds a knowledgeable doctor and who
begins a comprehensive rehabilitation program is the one who can look forward to a
life that is more productive and more comfortable.




Bibliography


American Lung
Association. www.lung.org.



Bates, David V.
Respiratory Function in Disease. 3rd ed. Philadelphia:
Saunders, 1989. Print.



Haas, François, and
Sheila Sperber Haas. The Chronic Bronchitis and Emphysema
Handbook
. Rev. ed. New York: Wiley, 2000. Print.



Hasleton, Philip, and Douglas B. Flieder,
eds. Spencer's Pathology of the Lung. 6th ed. Cambridge:
Cambridge UP, 2012. Print.



Hedrick, Hannah L.,
and Austin K. Kutscher, eds. The Quiet Killer: Emphysema, Chronic
Obstructive Pulmonary Disease
. Lanham: Scarecrow, 2002.
Print.



Matthews, Dawn D.
Lung Disorders Sourcebook. Detroit: Omnigraphics, 2002.
Print.



National Emphysema
Foundation. www.emphysemafoundation.org.



Spiro, Stephen G., Gerard A. Silvestri,
Alvar Agusti. Clinical Respiratory Medicine. 4th ed.
Philadelphia: Elsevier, 2012. Print.



West, John B.
Pulmonary Pathophysiology: The Essentials. 7th ed.
Philadelphia: Wolters Kluwer, 2008. Print.



Zirimis, Leonidas, Adelino Papazoglakis,
eds. Chronic Obstructive Pulmonary Disease: New Research.
New York: Nova, 2012. Print.

Friday, November 25, 2011

Symbolically connect Waverly to the fish the family eats for dinner in the final scene.


“On a platter were the remains of a large fish, its fleshy head still connected to bones swimming upstream in vain escape.”



Waverly, the narrator and young chess champion who keeps struggling with her mother, describes the family’s dinner this way. She’s just shown up at home after being out by herself for a few hours, having run away from her mother in the market. Waverly is very frustrated and embarrassed by the way her mother introduces her to strangers in the market; the girl seems to think her mother is taking credit for Waverly’s success as a chess prodigy.


But while Waverly is sitting alone, angry and cold and tired from running, she realizes that she has nowhere to go. There isn’t any escape from her mother or from her situation. This realization leads Waverly reluctantly back home to sit down to dinner with the family.


So, you can understand why Waverly would describe the fish on the dinner platter as a creature “swimming upstream in vain escape.” She identifies symbolically with the fish; both the creature and the young girl are trying desperately to find freedom and escape from the forces that are directing their lives.


With “its fleshy head still connected to bones,” the fish can also be symbolic of Waverly’s family unit. Waverly is the head; her mother is the bones. (Or vice versa, depending on your interpretation—I see Waverly as the head, since she’s the one facing a certain direction, trying to nudge away from her mother.) The mother and child, like the head and the bones, are connected to each other deeply. No matter how Waverly struggles to separate herself from her mother, she’s still a child under her mother’s care, and she’s still strongly influenced by her mother’s ideas and perspectives.

Thursday, November 24, 2011

What is the trachea?


Structure and Functions

The trachea, also commonly referred to as the windpipe, is the part of the airway that connects the larynx to the two main bronchi. The trachea is made up of sixteen to twenty hyaline cartilage rings that maintain the airway lumen width at about 2.5 centimeters. The cartilage rings are incomplete and flattened posteriorly, where they are completed by fibrous tissue and muscle fibers. The first cartilage ring is thicker than the others and connected by the cricotracheal ligament to the lower edge of the cricoid cartilage of the larynx. At its lower end, the trachea bifurcates into the right bronchus, which is wider, shorter, and more vertical, and the left bronchus which is narrower. This explains why aspirated foreign bodies are more likely to lodge in the right bronchus. The length of the trachea from top to bottom in an adult is 10 to 12 centimeters.



The anatomical relations of the trachea include the esophagus posteriorly and the great vessels of the neck laterally. The thyroid gland lies over the anterior surface in the lower neck. As the trachea enters the thorax, it is protected by the bony manubrium sterni. The cartilaginous structure is enclosed by an elastic fibrous membrane, and supported by nonstriated longitudinal muscle externally. Internally, transverse fibers of the trachealis muscle form a connection between the posterior ends of the cartilage rings.


In addition to its function of maintaining a patent (open) airway, the trachea also has the function of trapping foreign particles and of warming and moistening the air that flows to the lungs. It accomplishes this function by virtue of the lining of the tracheal lumen. The ciliated, respiratory mucosa of the tracheal lumen contains goblet cells that produce mucus. In the submucosa are numerous blood vessels that give warmth and seromucous glands that contribute to the lubrication of the airway. Blood supply to the trachea is from the inferior thyroid arteries. Nerve supply is from branches of the vagus and recurrent laryngeal nerves.




Disorders and Diseases

The most serious disorders of the trachea are those that cause interference with the airway. Tracheal stenosis can develop from trauma, tumors, radiation therapy, autoimmune diseases, and infection. The most common cause is prolonged intubation. Symptoms include shortness of breath, cough, and stridor. Treatment involves correcting any underlying medical condition, laser surgery, reconstructive surgery, dilation, and airway stenting. In 2008, the first tracheal transplant using patient stem cells was reported; in 2011, doctors implanted the first synthetic trachea.


Tracheomalacia occurs when the lumen of the trachea collapses inward, obstructing the airway during breathing or coughing. The most common cause of tracheomalacia is chronic obstructive pulmonary disease (COPD). Other causes include prolonged intubation, recurrent infection, injury from tracheostomy, and tumors or abnormal blood vessels that press against the trachea. A form of congenital tracheomalacia also exists. Symptoms are due to a compromised airway and are similar to tracheal stenosis. Management is also similar, including short- and long-term stenting and reconstructive surgery.


Acute inflammation of the trachea is usually the result of bacterial infection. Symptoms may resemble croup or epiglottitis, with cough, fever, and stridor. Bacterial tracheitis has become more common than acute epiglottitis as a cause of airway distress from bacterial infection. It is much less common than croup, occurring in only 0.1 cases per 100,000 children. Bacterial infection may follow trauma during intubation or a viral infection and is more common in pediatric patients. Treatment is usually successful with airway support and appropriate antibiotics, although mortality rates have been reported at 4 to 20 percent.




Perspective and Prospects

Tracheostomy is the most common surgical procedure performed on the trachea. The term “tracheotomy” implies a surgical opening made in the trachea. The term “tracheostomy” refers to an opening into the trachea that is kept open with a cannula (a tube) or made permanent. In most medical literature, however, the term “tracheostomy” is used to describe both procedures. The purpose of tracheostomy is to gain access to the tracheal airway in order to bypass a respiratory obstruction or to facilitate breathing. This potentially lifesaving procedure has been known since ancient times. There is a description of a healed tracheotomy incision in the Sanskrit hymns of the Rigveda, dating to 2000 bce The physician Chevalier Jackson (1865–1958) of Philadelphia is the founder of the modern tracheostomy, having described the indications, complications, and the basics of the modern surgical procedure. In the nineteenth century, the procedure was commonly done to relieve airway obstruction in diphtheria patients, and in the twentieth century polio was a frequent indication. Today, the most common indication is for prolonged ventilator-assisted breathing.


Tracheal surgery made history in 2008 when the first tracheal transplant
using a patient’s own stem cells was successfully performed. This milestone was accomplished by a team of doctors in Barcelona, Spain. The patient was a thirty-year-old woman who had scarring of her trachea from tuberculosis. A donor trachea was obtained and stripped of living cells. Stem cells from the woman’s bone marrow were then seeded into the trachea prior to transplantation. This procedure took yet another step forward in 2011, when scientists crafted an artificial trachea and seeded it with stem cells from a cancer patient, into whom it was then implanted by doctors in Sweden. This was considered a significant advance, because artificial organ transplantation does not require a donor and carries no risk of rejection by the recipient's body.




Bibliography


Cummings, W. Charles, et al. Otolaryngology: Head and Neck Surgery. 4th ed. Philadelphia: Mosby/Elsevier, 2005.



Drake, L. Richard, et al. Gray’s Anatomy for Students. 2d ed. New York: Churchill Livingstone/Elsevier, 2009.



Engels, P. T., et al. “Tracheostomy: From Insertion to Decannulation.” Canadian Journal of Surgery 52, no. 5 (October, 2009): 427–433.



Lalwani, K. Anil. Current Diagnosis and Treatment in Otolaryngology: Head and Neck Surgery. 3d ed. New York: McGraw-Hill, 2012.



Macchiarini, P., et al. “Clinical Transplantation of a Tissue-Engineered Airway.” The Lancet 372 (2008): 2023–2030.



"Tracheotomy." Health Library, November 26, 2012.

Wednesday, November 23, 2011

What is pharmacy?


Science and Profession

Traditionally, pharmacy was confined to the distribution and dispensation of medications, but modern pharmacists have become recognized drug experts. The concept of pharmaceutical care promises to change pharmacy practice for the public’s benefit.



Pharmacy has always been primarily a retail practice. In the early days of the profession, physicians would often choose not to prepare medications for their patients, instead referring them to apothecaries, who would receive the prescriptions and then prepare and dispense them. A patient who was familiar with the symptoms of his or her ailment might choose to return to the apothecary to seek another course of this medication. Recognizing that many problems responded well to standardized medicinal formulas, many apothecary shops began to sell ready-made products to accommodate patients who chose to seek care from the pharmacist rather than the physician. A similar situation exists in modern times with over-the-counter medications, which are available without a prescription.


Until the 1970s, basic pharmaceutical practice changed very little. Physicians continued to devote themselves to the diagnosis and treatment of patients, and pharmacists continued to concentrate on dispensing pharmaceutical products. By this time, most of the collection and preparation (compounding) phases of the medication-developing process were being performed by the suddenly expanding pharmaceutical industry. Most medications arrived at the pharmacy in a ready-to-dispense form, such as a tablet, capsule, elixir, syrup, suppository, or ointment. This trend has progressed to the point that fewer than 1 percent of prescriptions require compounding by the pharmacist.


Most people have some understanding of pharmacy and pharmacists, usually through visits to the local drugstore. In this setting, pharmacists practice what is known as retail or community pharmacy. For many customers, it is unclear whether the pharmacist is a businessperson or a health-care professional; in fact, the answer is both. On one hand, a pharmacy often sells merchandise that many people associate with a variety store, such as pens, greeting cards, gift items, and beauty products. On the other hand, a pharmacy also has a license to sell something no variety store can: prescriptions, such as antibiotics for infections, pain medication for broken bones, or medication for high blood pressure to help prevent a stroke or heart attack.


Modern retail pharmacists operate and manage complex businesses. Pharmacists in this setting have additional challenges, such as personnel management, the organizational structure of the pharmacy, and the general focus of the business. Unrecognized activities may involve location analysis and selection, obtaining loans to purchase and operate the business, and store design. The pharmacist must evaluate computer systems for the purposes of dispensing medicine, controlling inventory, reordering stock, and interfacing with insurance companies for payment.


Not all retail pharmacy activity occurs in a community-based store. Many companies have founded large conglomerates called chain pharmacies. Occasionally, these chain stores may resemble independent community stores, but they still share common ownership. Most people are familiar with typical chain pharmacies within supermarkets and discount stores. Retail sales of prescription medicines have become increasingly available on the Internet as well.


Pharmacies in certain other practice sites, such as hospitals, are associated with the dispensation of many varied and highly complex medications. The medications dispensed in a hospital cannot be given to the patient for self-administration. Such medications include intramuscular or intravenous injections, implantable drug reservoirs, beads containing drugs, and medications requiring close observation of the patient. Hospital practice places a unique demand on the pharmacist to be a resource for drug information. Specialized pharmacists may become members of health-care teams where they provide a service to improve patient care rather than supplying a product.


During the 1980s, the insurance industry in the United States reformed payment methods for hospitals, trying to reduce the time that each patient remains in the hospital. The goal was to minimize cost by allowing the patient to recover at home. This policy reduced expensive payments to hospitals and shifted the expense to less costly home health care. Pharmacy’s ability to provide sophisticated medications in this setting allows the patient to stay at home and has created a growing segment of practice for some pharmacists.


Pharmacists are not limited to the practice types or settings mentioned above. Large pharmaceutical-manufacturing firms also employ many pharmacists in sales, marketing, management, and product development and manufacturing positions. Some pharmacists direct clinical research efforts, while others perform quality assurance or market research or hold positions in upper management.


One career track with tremendous significance to the profession is pharmacy education, a process that has seen many changes. Historically, European apothecaries used an apprenticeship system with no requirement for formal education; in contrast, modern pharmacists are well educated, often having more than 150 college-credit hours at graduation. After graduation, many pharmacy students will choose further study for an advanced degree. These degrees may focus on management (master of business administration, master of hospital pharmacy), academic work (master of science, doctor of philosophy), or postgraduate clinical studies (doctor of pharmacy). Traditionally, after completion of an advanced degree, most pharmacists join faculties at colleges of pharmacy. Others are recruited by institutional and corporate employers who find that such advanced training provides employees with skills that are beneficial to company operations.


The pharmacy student must complete an extensive application process to gain entry into a college of pharmacy. In addition to good grades, applicants usually must score well on the Pharmacy College Admission Test (PCAT), although this test is not required by all schools. Generally, an applicant must have a minimum of sixty-five hours of prepharmacy education. In the United States, required courses include English composition, general and organic chemistry, general biology (or botany and zoology), college physics, college algebra and trigonometry, principles of accounting, American history, principles of economics, and electives in the humanities and behavioral or social sciences.


One emerging area of pharmacy practice is the provision of clinical services. Clinical pharmacists are high-level consultants and experts on drug therapy and related issues. Many conduct daily patient rounds with physicians and other health-care providers. These clinical specialists review medication orders for appropriateness, verify proper doses, inform nurses of special issues when giving the medication, recommend laboratory tests and other monitoring procedures, and assess the outcome of treatment with the physician.


Once, most clinical specialists were associated with general internal medicine services. Then the need for clinical pharmacy services in other areas became apparent. To serve these patients properly, pharmacists established specialty practices. Recognized specialty areas in pharmacy include pediatrics, geriatrics, nutrition, drug information, ambulatory care, critical care, family medicine, surgery, cardiology, oncology, nuclear medicine, mental health, and pharmacokinetics, a specialty unique to pharmacists. Pharmacokinetics is a branch of pharmacology that studies what happens to a medication when it enters the body. These practitioners help choose the best dose of a medication in order to optimize clinical outcomes.


The increasing demands for enhanced services and the growing complexity of the tasks required to provide clinical services resulted in a need for further training. Many pharmacy specialists undergo residency training to provide this additional proficiency. In the United States, the Board of Pharmacy Specialities established credentials to allow pharmacists to become board certified within many of these specialty areas. Nonspecialized residency training is available in general hospital pharmacy practice. The hospital is becoming a complicated practice site that requires unique knowledge; this type of training addresses the particular needs of pharmacists in hospital practice.


A lesser-known area of practice for pharmacists is clinical research. The pharmacist may serve as the principal investigator or as a research coordinator for another investigator. The research may address questions about drugs already on the market, evaluate new treatments, or gather information about drug-related problems. In the United States, clinical research usually serves to provide the background material required by the Food and Drug Administration for a pharmaceutical manufacturer to sell a new medication. Results of this research are published in medical and pharmacy journals so that interested professionals have easy access to this new information and can apply it to patient care.




Diagnostic and Treatment Techniques

Pharmaceutical care involves four major functions: curing disease, eliminating or reducing a patient’s symptom complex, arresting or slowing a disease process, and preventing a disease or its symptom complex. A pharmacist works with other professionals to design, carry out, and monitor a therapeutic plan that will produce specific therapeutic outcomes for the patient. These activities involve three major functions: identifying potential and actual drug-related problems, preventing potential drug-related problems, and resolving actual drug-related problems. This concept was conceived in the late 1980s by the nationally noted pharmacy educators Charles D. Hepler and Linda H. Strand, who recognized that pharmaceutical care is applied on three distinct levels: primary (outpatient and community pharmacies), secondary (acute care hospitals, skilled nursing facilities, home health care, and specialized care programs, such as oncology and pain control), and tertiary (inpatient critical care and teaching medical centers). Each level of practice demands specialized services from the pharmacist.


The specifics of pharmaceutical care have been described by noted pharmacists William E. Smith and Katherine Benderev as the sum of all pharmaceutical services, both clinical and nonclinical, that are required and received by a patient. The provision of pharmaceutical care means that the pharmacist is responsible for a patient’s achievement of the desired clinical outcome secondary to the use of medications. Inherent in this idea are the basic functions of the pharmacist common to all levels of care: developing and using a patient's medication profile; interpreting, questioning, clarifying, verifying, and validating all drug-related orders; providing a safe and efficient drug-dispensing system; monitoring drug therapies for safety, efficacy, and desired clinical outcome; screening for drug allergies, drug interactions, and concomitant drug use; detecting and reporting drug allergies and adverse reactions; recommending initial or alternative drug therapies; responding to drug information requests from physicians, nurses, and patients; teaching health-care providers and patients about drug use; obtaining medication histories by interviewing patients; assisting in the selection of the drugs of choice and dosage forms; conducting drug-use evaluations in order to gauge the appropriateness of drug use and the achievement of desired therapeutic outcomes; and applying pharmaceutical principles for selected drug therapies.


Pharmacy practice in a retail setting primarily stresses filling prescriptions, but many activities behind the scenes also help the patient. In addition to buying safe and reasonably priced products, the pharmacist must maintain a patient profile, which includes data about the patient's allergies, other medications, and other relevant information. The pharmacist uses the system to screen for drug interactions, to avoid potential allergic reactions, and to ensure that the patient receives proper doses of the medication.


Traditionally, patient education by pharmacists has consisted of a brief discussion augmented by precaution labels on prescription bottles. Pharmacists and other health-care professionals have since recognized the importance of more thorough patient education in achieving optimal results using medications. Methods include one-on-one counseling, audiovisual programs, preprinted or computer-generated handouts, and other specific information sources. Some retail pharmacists use their computer systems to send refill reminders, allowing pharmacists to assist physicians in their efforts to ensure that people with chronic problems are treated adequately. Hospital-based pharmacists may implement detailed discharge counseling for patients returning home in order to review treatment plans or answer questions about medications unfamiliar to the patient.


Many pharmacists perform a very valuable service in nursing homes and long-term care facilities by evaluating patients’ medication regimens for problems. Elderly patients often use six or more medications, making them more prone to dangerous drug interactions. They may also have many illnesses, making them more sensitive to the adverse effects of medications. Pharmacists assess whether chronic conditions are being controlled, whether medications are being stored and dispensed properly, and whether efforts to ensure the patient’s safety are adequate. The latter activity may include recommendations to stop the use of a medication because of side effects, drug interactions, or toxicity. Also, the pharmacist may recommend laboratory tests to monitor drug therapy.


One area where pharmacy practice is expanding is hospital practice. In the United States in the 1960s, the pharmaceutical-manufacturing process began to see radical growth, with both the numbers and the complexity of medications increasing steadily. Hospitalized patients place unique demands on pharmacists for specialized services. These pharmacists maintain their control and responsibility for dispensing medication, yet their role has extended into being part of the drug decision-making process. A simple example is a change in the traditional role of controlling medication inventory. The hospital pharmacist will establish and use a formulary, a list of medications approved for use in the hospital. Formularies control medication costs by preventing the purchase of unneeded products and placing restrictions on the use of expensive or dangerous medications. The pharmacist helps make complex decisions, such as determining the proper doses of highly toxic medications. Since hospitalized patients are very ill, watching for potential allergic reactions and side effects is very important. For cases in which treatment decisions are unclear, the pharmacist may aid the physician in selecting a treatment.


Often, hospitalized patients require special methods for the administration of medication. Pharmacists need to be knowledgeable about intramuscular and intravenous routes of administration. Intravenous medications may require complex mixing and preparation. These products must remain sterile, with no bacteria present, and may have special storage or handling requirements. Frequently, intravenous medication is given over a fixed amount of time; therefore, the pharmacist must be familiar with the infusion pumps that regulate the amount of solution dispensed over a given period. Many medications also require specialized tubing called catheters for administration. The pharmacist plays a central role in addressing any special needs of patients requiring complex medications.


All these activities require the pharmacist to work closely with other professionals in the hospital. Frequently, the pharmacist will work with nurses to ensure proper administration and timing of doses or to monitor the patient for side effects. Laboratory personnel need to understand that medications may affect certain laboratory tests. In addition, laboratory technicians may draw blood from the patient to check the concentrations of many types of medication. Proper timing of the sample collection is very important when considering making changes to the patient’s drug therapy.




Perspective and Prospects

Pharmacy is a unique profession whose origins can be traced to the thirteenth century, when the Holy Roman emperor Frederick II issued an edict to separate the professions of pharmacy and medicine. Pharmacy became responsible for the preparation and dispensation of medications, and medicine became responsible for the diagnosis and treatment of the patient.


No professional practice is without change. Pharmacy practice evolved from the gathering, extraction, and preparation role of the apothecary to the contemporary role of medication distribution. Now, with the complexity of drug therapies increasing rapidly as new medications enter the market, physicians are becoming increasingly dependent on pharmacists to keep them informed of new developments, and pharmacists have become more active in dealing with patients and their physicians. Pharmaceutical care is a natural extension of this evolution, in which the pharmacist’s role becomes more patient centered rather than focusing on a product. The tenets of pharmaceutical care promise to become deeply ingrained in the practice of pharmacy, replacing the dated idea that a pharmacist's only role is to dispense medications.




Bibliography


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