To critically review the role of coronary angioplasty for acute myocardial infarction.

Immunosuppressed patients are at risk for developing cytomegalovirus retinitis. This disorder is the most common cause of vision loss in patients with the acquired immunodeficiency syndrome (AIDS). Cytomegalovirus retinitis is probably the result of hematogenous spread of the virus to the retina after systemic reactivation of a latent cytomegalovirus infection. Although the ophthalmic infection may initially be asymptomatic, the retinal necrosis it produces may result in both loss of visual field and decreased visual acuity. Routine screening of these patients is required for early diagnosis. The retinitis is detected with ophthalmoscopy as either a perivascular yellow-white retinal lesion frequently associated with retinal hemorrhage or as a focal white granular infiltrate, often without hemorrhage. Both lesions enlarge in a progressively expanding "brushfire" pattern. The diagnosis of cytomegalovirus retinitis, as well as the evaluation of its response to therapy, is determined primarily by clinical criteria. Serial retinal photography is an objective method to assess the changing appearance of these lesions. Ganciclovir and foscarnet are investigational antiviral drugs that appear to be effective in treating cytomegalovirus retinitis. However, maintenance therapy with these medications is required after initial treatment because the disease often relapses. The combined expertise of the internist and the ophthalmologist is needed to diagnose and treat these patients.

Nutritional modulation is one approach to successful aging. In animals, dietary restriction increases life span. Alterations in the macronutrient and micronutrient constituent of the diet can modulate gene expression. Anorexia is common in elderly persons. The results of studies in animals suggest that aging is associated with a decrease in the opioid feeding drive and an increase in the satiating effect of cholecystokinin. Unrecognized depression is a common, treatable cause of anorexia and weight loss in elderly persons. Protein synthesis decreases in elderly persons; nevertheless, nitrogen balance can be maintained in patients with fairly low intakes of protein. Carbohydrate intolerance is common and may be modulated by nutritional intervention and physical activity. The role of cholesterol in the development of heart disease in very old persons is controversial. Homebound and institutionalized elderly persons often do not expose their skin to sunlight; because the skin of older persons has a decreased ability to form vitamin D, the vitamin D status in these persons is precarious and they are at risk for osteopenia. Vitamins are often abused by elderly persons. Drug administration alters the vitamin requirements of persons. Borderline zinc state has been associated with deteriorating immune function, especially in persons who have diabetes mellitus or who abuse alcohol. Zinc administration appears to protect against the deteriorating vision associated with age-related macular degeneration. Selenium deficiency seems to be associated with an increased prevalence of cancer.

The decision to use bedside pulmonary artery catheterization for managing patients must involve a careful assessment of the risks compared to the benefits. Complications can be minimized by following specific guidelines for catheter insertion and maintenance. Pulmonary artery catheterization has been shown to be more accurate than clinical assessment alone in critically ill patients for determining the cause of shock (hypovolemic, cardiogenic, or septic) or for assessing the cause of severe pulmonary edema (cardiogenic or noncardiogenic). The diagnosis of cardiac failure in medical or surgical patients with invasive hemodynamic monitoring provides physiologic data that guide pharmacologic treatment that may favorably influence preload and afterload in the failing or ischemic heart. Managing hemodynamics with the aid of pulmonary artery catheterization in patients with the adult respiratory distress syndrome has received considerable attention, but a contribution to better patient outcome has not been established. Similarly, although clinical management of hemodynamic instability in septic shock is facilitated by pulmonary artery catheterization, the mortality remains very high because of the lack of specific therapy to reverse the sepsis syndrome. Adequate volume resuscitation and improved tissue oxygenation are universally accepted goals, but specific hemodynamic endpoints are controversial and direct measurements of tissue oxygenation are not possible. Prospective studies to define the clinical value of pulmonary artery catheterization are needed, but must be designed very carefully in order to identify unequivocally the effect of pulmonary artery catheterization on outcome in critically ill patients.

To appraise critically the clinical indications for diagnostic evaluation of carotid artery disease and the efficacy, safety, limitations, and relative costs of commonly used noninvasive diagnostic tests.

Since bovine parathyroid extract became unavailable for stimulatory testing, the differentiation between hypoparathyroidism and pseudohypoparathyroidism has been made from the measurement of serum parathyroid hormone (PTH) values alone. Responsiveness to PTH can once again be tested with teriparatide acetate, the newly available, biologically active 1-34 fragment of human PTH. The PTH infusion test can be used to confirm a preliminary diagnosis based on serum immunoreactive PTH values, to differentiate between type 1 and type 2 pseudohypoparathyroidism, or to detect a subtle abnormality of calcium metabolism in normocalcemic patients with features suggesting pseudohypoparathyroidism. Of several variables used to express changes in renal metabolism of cyclic adenosine 3',5'-monophosphate (cAMP) or phosphate, the 30-minute change in cAMP excretion per unit of glomerular filtration and the 60-minute percentage fall in the tubular maximum for phosphate reabsorption provide the best discrimination. Teriparatide has a low incidence of adverse reactions and provides an effective diagnostic tool.

After the accidents at Chernobyl, the Soviet Union, and in Goiania, Brazil, there is increasing concern about the medical risks from radiation accidents. This overview summarizes the principles of nuclear energy, the biologic effects of accidental radiation exposure, the emergency response to nuclear accidents, and approaches to treating radiation injuries. Also discussed are the related issues of reactor safety, the disposal of radioactive waste, and the proliferation of nuclear weapons. With the increasing use of radioactive materials for power, weapons, and medical diagnostics, the medical community needs to understand the health consequences of radiation exposure.

As a result of important advances in medical imaging, the oral cholecystogram is no longer the primary test of gallbladder function and anatomy. Real-time ultrasonography and cholescintigraphy, both highly sensitive and specific tests, are the two major methods for assessing gallbladder pathology. Oral cholecystography, endoscopic retrograde pancreatography, and percutaneous gallbladder puncture serve as supplementary tests. Decisions about which test to use depend on the kind of gallbladder disease that is suspected as well as the estimated likelihood of the disease before the information is obtained from the procedure. Thus, ultrasonography is the test of choice for chronic cholecystitis, with oral cholecystography reserved for situations in which the diagnosis is uncertain after ultrasonography. When acute cholecystitis is suspected, ultrasonography is also the test of choice in most patients, and cholescintigraphy is used to resolve uncertainty.

To describe the spectrum of illnesses associated with Escherichia coli O157:H7 infections.

Diabetes mellitus in nonpregnant adults is a chronic affliction that leads to significant vascular and neuropathic disease. Diabetes during pregnancy can lead to perinatal complications. Both of these types of diabetes are common, often asymptomatic, and readily diagnosable by glucose tolerance testing. As a result, screening can identify many previously undiagnosed patients. However there is only limited evidence that screening results in net therapeutic benefit. In the case of gestational diabetes, controlled trials indicate that hypoglycemic therapy decreases the frequency of macrosomia, but has no effect on perinatal mortality. Our analyses indicate that screening for gestational diabetes is a low-cost intervention that produces a small expected benefit. Screening for diabetes in the nonpregnant adult (almost always a type II diabetic) is not recommended, because the link between improving glucose control and reducing diabetic complications is currently too weak. Screening might be reasonable for particular patients, for example, obese persons who would be spurred to lose weight by a demonstration of glucose intolerance. Screening for type I diabetes followed by immunomodulating therapy is still too experimental for confident analysis.