Melanoma recurrence after excision. Is a wide margin justified?

Through retrospective analysis of patient records for 187 patients with melanoma seen between 1975 and 1989, the aim of this study was to determine whether outcome varied according to degrees of surgical intervention in the primary treatment of stage I disease for thin, intermediate, and thick lesions. There were no significant differences in recurrence rate associated with an excision margin of 15 mm or less compared with wider excision margins; with initial excision compared with wider re-excision after excision biopsy; or for primary closure as compared with closure with a graft. There was, however, a significant difference in wound complication rate between wounds closed primarily (6%) and those closed by grafting (31%) (p < 0.01). The authors advocate the more conservative excision margin of 1.00 cm to 1.50 cm in the treatment of stage I melanoma with primary closure of the wound where possible.     

Effects of transport inhibitors on the generation and transport of a soluble viral glycoprotein

The generation and transport of the soluble glycoprotein (Gs) of wild-type vesicular stomatitis virus (VSV) were studied using cell fractionation and transport inhibitors. Gs was found in the rough endoplasmic reticulum (RER) and the Golgi-enriched membrane fractions of infected Chinese hamster ovary cells. The identity of intracellular Gs was confirmed by its precipitation with a monoclonal antibody to the ectodomain but not with a anti-peptide antibody directed against the first 15 amino acids at the carboxy terminus of the VSV transmembrane glycoprotein G. Their extracellular appearance was affected in a concentration-dependent manner by monensin and carbonyl cyanide m-chlorophenylhydrazone (CCCP) and was completely inhibited by incubation at 20 degrees. Inhibitors failed to dissociate the transport of Gs from G. These experiments indicate that in fibroblast cells Gs can be generated intracellularly, probably in the RER, and that Gs, like G, is transported from there to the Golgi complex and then presumably to the extracellular environment.     

Current and future concepts in stroke prevention

STROKE IS A MAJOR CAUSE OF MORBIDITY and mortality in an aging population. The current understanding of the pathophysiology of atherosclerotic diseases, the most common cause of stroke, and the evidence for existing therapeutic interventions for the prevention of stroke are presented. Specifically, we review the evidence for antiplatelet agents, anticoagulants, antihypertensive medications, lipid-lowering agents and carotid endarterectomy for stroke prevention.     

Mitral valve regurgitation

The mitral apparatus is a complex structure composed of several components, each of which can be affected by a variety of diseases, resulting in mitral regurgitation. The physiologic consequences of mitral regurgitation include reduced forward stroke volume; increased left atrial volume and pressure; and reduced resistance to left ventricular ejection. The latter explains why indices of systolic left ventricular function (ejection fraction) are often increased early in the course of mitral regurgitation. With the insidious development of mitral regurgitation, the left atrium dilates to accommodate the increase in volume, thereby reducing the atrial pressure. However, with the acute development of mitral regurgitation into a nondilated left atrium, pressure rises rapidly, producing pulmonary edema. The predominant clinical symptoms in chronic mitral regurgitation of dyspnea and fatigue result from pulmonary venous hypertension and low cardiac output. The cardinal physical finding is a mitral systolic murmur. Since the murmur can assume various configurations, the most reliable way to establish its correct origin is by bedside physiologic maneuvers. Typically, in the beat following a premature contraction or after a long pause during atrial fibrillation, the murmur of mitral regurgitation is unchanged in intensity, but murmurs due to left ventricular outflow obstruction increase. Also, isometric handgrip exercise increases the intensity of the murmur and a Valsalva maneuver decreases it during the strain phase. Echocardiography is the most useful noninvasive technique for evaluating patients with mitral regurgitation. Visualization of the mitral apparatus may establish the etiology of regurgitation, and measurement of left atrial size and left ventricular size and performance is useful for assessing the functional significance of the lesion. Doppler echocardiography can establish the diagnosis of mitral regurgitation in difficult cases with multi valve disease and can estimate the severity of the regurgitation. Cardiac catheterization and angiography are usually reserved for the patient being considered for valvular surgery. The natural history of chronic mitral regurgitation is characterized by slowly progressive symptoms, and often the onset of disabling symptoms is the result of irreversible left ventricular dysfunction. Medical therapy consists of digitalis, diuretics, and vasodilators for symptomatic patients. When symptoms occur despite this therapy, valvular surgery should be considered before left ventricular function becomes abnormal.