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Biomedical subjects

A Zucker

Publications and source records attributed to A Zucker.

At least 37 records · Page 2Linked to original sources

Blind use of the double-lumen plugged catheter for diagnosis of respiratory tract infections in critically ill children.

Transtracheal aspiration, percutaneous lung biopsy, and tracheal aspiration can be dangerous and/or unreliable methods for obtaining specimens of pulmonary secretions for culture. Using a blind technique, we evaluated the efficacy of a double-lumen catheter (DLC) with a polyethylene glycol plug in obtaining specimens of respiratory tract secretions for culture, and compared these results with simultaneously obtained cultures of tracheal aspirates. Twenty-seven intubated children already receiving antibiotic therapy were studied. Sixteen (59%) DLC specimens were sterile, as opposed to only 6 (22%) tracheal aspirates. Only 2 (8%) of the DLC specimens were contaminated. Two DLC specimens yielded significant bacterial growth (at least 10(5) colony-forming units/ml). Using DLC culture data, there was an 81% success rate in making decisions concerning antibiotic selection. We conclude that blind use of the DLC is a safe and reliable method of obtaining pulmonary secretion specimens for culture.

Adolescent↗

Hypomagnesemia is a common complication of aminoglycoside therapy.

Normal therapeutic dosages of aminoglycosides can cause hypomagnesemia in more than one-third of patients. Hypomagnesemia occurs early in therapy, results in renal Mg++ wasting and may produce hypocalcemia and hypokalemia. Patients who are NPO, eating poorly or not receiving supplemental Mg++ are at high risk for hypomagnesemia. Hypomagnesemia, hypocalcemia and hypokalemia respond to Mg++ replacement therapy. We recommend serial monitoring of serum Mg++ levels in patients receiving aminoglycoside therapy.

Aminoglycosides↗

Effect of water deprivation on urinary excretion of PGE2 in the dog.

We examined the influence of the state of hydration on the urinary excretion of prostaglandin E2 (PGE2) and kallikrein in the dog. Immunoreactive PGE2 and kallikrein were measured in the urine of conscious dogs during periods of water deprivation and periods of free access to drinking water and in the urine of time-control dogs that had free access to water throughout the study. During water deprivation the excretion of kallikrein did not change significantly, but PGE2 excretion increased by 50 and 75% (P less than 0.05) after 2 and 4 days, respectively, associated with reductions of body weight and urine flow and with elevation of plasma renin activity, plasma sodium, and both plasma and urine osmolality. Dehydrated dogs drank copiously when allowed free access to water, and over the following 4 days both PGE2 excretion and plasma renin activity fell significantly, associated with elevation of body weight and urine volume and with lowering of plasma sodium and plasma and urine osmolality. In contrast, if after 4 days of water deprivation the dogs were kept at a constant level of dehydration by restricting their water allotment on subsequent days to 300 ml/day, PGE2 excretion and most other variables remained at the dehydration level. In conclusion, these results suggest that renal PGE2 production is dependent on the state of hydration in the dog.

Animals↗

Dietary sodium intake: a determinant of postprandial plasma sodium concentration in the dog.

1. The effect of dietary sodium intake on pre- and post-prandial plasma sodium concentrations and on the pattern of sodium and potassium excretion was determined in conscious female dogs, who were allowed free access to water and were fed on commercial low sodium diets supplemented with 0, 50, 100 or 250 mmol of sodium chloride/day for 6 days. 2. The preprandial plasma sodium concentration was not altered by the dietary sodium intake. However, the 4 h postprandial plasma sodium concentration was linearly related to the magnitude of dietary sodium intake, whereas the 8 h postprandial plasma sodium concentration was elevated only in dogs receiving 250 mmol of sodium/day. 3. The (0-8 h/0-24 h) ratio for urinary sodium excretion was significantly correlated with both the dietary sodium intake and the postprandial increase in plasma sodium concentration. 4. The 24 h excretion of potassium was not markedly affected by the dietary sodium intake; however, the (0-8 h/0-24 h) ratio for potassium excretion was significantly correlated with both the dietary sodium intake and the (0-8/0-24 h) ratio for sodium excretion. 5. These data indicate that: (a) postprandial increases in plasma sodium concentration need to be considered when evaluating the mechanisms involved in the daily regulation of sodium balance; (b) the daily pattern of potassium excretion is closely linked to the dietary sodium intake.

Animals↗

Renal and endocrine response to water deprivation in dog.

Plasma and urine sodium, potassium, osmolality, aldosterone, and plasma renin activity (PRA) were measured in time controls and during control dehydration and rehydration periods in conscious dogs fed a 50 mmol NaCl diet. During 4 days of water restriction, plasma sodium and osmolality and PRA were elevated, whereas plasma potassium and aldosterone were not affected. Urinary potassium excretion was elevated above intake levels during the entire dehydration period, whereas Na excretion was only elevated during the first 2 days of dehydration. Unrestricted rehydration was associated with a marked fall in plasma sodium and osmolality, a decrease in PRA, and no change in plasma potassium or aldosterone. In addition, during the 1st day of rehydration, there was marked retention of sodium and potassium. Thus, in the dog, dehydration and subsequent rehydration cause significant alterations in sodium and potassium balance and marked alterations in PRA that are not associated with changes in either plasma aldosterone concentration or urinary aldosterone excretion.

Aldosterone↗

Holism and reductionism: a view from genetics.

The terms "holism" and "reductionism" are often used loosely - especially in medical contexts. In an attempt to remedy this, these terms are explored from the standpoints of: philosophy of science, medicine, genetics, history of genetics and clinical genetics. A sense for "reductionism" is developed in part by focusing on the related histories of classical genetics and clinical genetics. This done, the dichotomy between holism and reductionism, whether in basic genetics or the genetic counseling situation, loses much of its force.

Genetic Counseling↗

Even dying must be edited: further thoughts on Joan Robinson.

"Joan Robinson: One Woman's Story' is a cinéma vérité style record of a woman's losing struggle against ovarian cancer. The film has been shown now twice on the American Public Television Network. It has received good notices primarily from the lay press. Yet the film depicts much that is out-of-date and much that is debatable. In general, we feel that it presents a depressing picture of the cancer patient. This was not Joan Robinson's intention and her bravery only serves to highlight this picture of suffering with cancer. We point to specific flaws in the film. We then go on to account for why many reviewers seem to have been blind to these flaws. It is suggested that criteria for good works of art, for good public health information, and for admirable personal traits were confused.

Adult↗

Lack of evidence for gastrointestinal control of sodium excretion in unanesthetized rabbits.

Experiments were performed to determine whether unanesthetized rabbits exhibit a greater natriuresis after oral administration of a hypertonic sodium chloride solution (1.5 mmol NaCl/kg) than after the intravenous administration of the same solution. Male rabbits (New Zealand) were placed on a low sodium diet for 4 days, and on the fifth day a hypertonic NaCl solution (616 mM) was given either by stomach tube (GI) or intravenously (IV), while an equal volume of a hypotonic NaCl solution (31 mM) was given by the alternate route. The studies were repeated on each rabbit so that paired observations were obtained. No differences in plasma Na concentration, peripheral hematocrit, or urinary sodium excretion were observed between the GI and IV groups after administration of the hypertonic NaCl solution. In seven rabbits that were permitted access to food and water following NaCl administration by either route, urinary sodium excretion tended to be reduced (P = 0.08), but, again, no significant differences in plasma sodium concentration, peripheral hematocrit, or urinary sodium excretion were observed between the GI and IV routes of sodium administration. Accordingly, we could find no evidence to support the existence of a GI or portal Na receptor system that regulates urinary sodium excretion in the unanesthetized rabbit.

Administration, Oral↗

Terminal and safe.

Decisions regarding the legislation of drugs such as laetrile require a careful analysis of the concept of terminal. If "terminal" is characterized to allow for a time span between diagnosis and death, and if cure is not taken as a paramount goal of a drug, then safety and effectiveness may apply to drugs used for the terminal. If this is so, then arguments for allowing laetrile use will have to appeal to principles of freedom and medical sociology and not to a traditional analysis of safety and effectiveness.

Government Regulation↗

Renin response to hemorrhage and hypotension in the aglomerular toadfish Opsanus tau.

Renal renin and the juxtaglomerular cells evolved in primitive bony fishes, whereas the macula densa emerged later in vertebrate phylogeny. We attempted to determine whether a renal arteriolar baroreceptor exists in the toadfish Opsanus tau, which possess renin and granulated cells in the kidneys, but lack glomeruli and macula densa. Cumulative hemorrhage of 1.5, 3, 6, 12, and 18 ml/kg, or a single massive bleeding from unanesthetized toadfish, kept in 50% seawater, caused an immediate and significant decrease in mean aortic pressure and stepwise increases (5-20 times) of plasma renin activity (PRA). Papaverine (10 mg/kg) caused hypotension and increased PRA. Minoxidil (6-12 mg/kg) neither decreased blood pressure nor increased PRA. The results suggest that toadfish respond to hemorrhage and acute hypotension with renin release despite the absence of a macula densa. It remains to be determined whether decreased renal perfusion pressure due to decreased dorsal aortic pressure stimulated the receptor in the granulated cells or whether the renal nerves may be involved.

Angiotensinogen↗