The American journal of medicine
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Left ventricular hypertrophy is both a target organ response to hypertensive vascular disease as well as a factor that might be responsible for other cardiovascular events. Recent work confirms that the increased cardiac mass associated with hypertension results as a structural adaptation to the increased afterload imposed on the heart. Initially there is a transient period of hyperfunction that is followed by the sustained structural adaptative period of stable hyperfunction. ⋯ These include: the pressor mechanisms per se; the age, sex, and race of the patient; and coexisting diseases. Some of these factors may account in part for the regression of cardiac mass with antihypertensive therapy. However, until we understand more clearly those factors that transduce the physical stimulus for hypertrophy into biochemical events, we shall neither understand completely the development of this structural adaptation of the heart nor its regression with treatment.
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The left ventricle adapts to an increased afterload such as that produced by arterial hypertension with concentric left ventricular hypertrophy. However, this adaptive process can be modified by a variety of physiologic and pathophysiologic states. Progressive aging, black race, and perhaps disorders with an increased sympathetic outflow seem to accelerate left ventricular hypertrophy. ⋯ Left ventricular hypertrophy has been shown to increase ventricular ectopic impulse generation and to put patients at a high risk of sudden death. Moreover, the increase in myocardial mass lowers coronary reserve and enhances cardiac oxygen requirements. Thus, the presence of left ventricular hypertrophy has to be considered as an ominous sign rather than as a benign adaptive process.
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Quantitative criteria distinguish bacterial infection (or colonization) of the urine from contamination. These criteria depend on the fact that the density of bacteria in infected urine is usually several orders of magnitude higher than the density of bacteria in contaminated urine. Most research on quantitative definitions of infection has concerned Gram-negative rod infections in women. ⋯ For acute dysuria and frequency, recent evidence supports the use of a colony count of 1 X 10(2) cfu/ml bacteria as the most useful criterion. For the diagnosis of catheter-associated urinary tract infection, the criterion of 1 X 10(5) cfu/ml has been used most commonly, although a lower threshold may be appropriate. Additional investigation is required to determine the most appropriate quantitative definition of infection in this and several other circumstances.
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The cerebrospinal fluid is a dynamic, metabolically active substance that has many important functions. It is invaluable as a diagnostic aid in the evaluation of inflammatory conditions, infectious or noninfectious, involving the brain, spinal cord, and meninges. ⋯ Age-related and compartmental variations in chemical and cellular composition are important considerations in the interpretation of results. Alterations in cerebrospinal fluid constituents from different pathologic processes may be similar in certain circumstances and cause interpretation difficulties.
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Review Comparative Study
Idiopathic mesangiocapillary glomerulonephritis. Comparison of types I and II in children and adults and long-term prognosis.
Of 104 patients with idiopathic mesangiocapillary glomerulonephritis studied for at least two years, 69 patients had type I disease and 35 had type II. Forty-five patients were children, and 59 were adults. Type II mesangiocapillary glomerulonephritis was more common in children than in adults, but no other clinical feature distinguished the two types at onset. ⋯ During a follow-up period of two to 21 years (mean eight years), only seven patients (five with type I and two with type II) showed clinical remission, whereas 38 percent of patients with type I and 49 percent of patients with type II died or required dialysis; a further 23 percent of patients with type I and 16 percent of patients with type II had continuing disease and reduced glomerular filtration rate. Only the presence and persistence of a nephrotic syndrome in type I predicted renal failure. In both types, the presence of sclerosis or crescents in the initial renal biopsy specimen was associated with a poorer prognosis, but no other feature was of major prognostic value.