Biomedical subjects
Publications and source records attributed to A Zucker.
A family had a child in large part to use its marrow in the hopes of saving the life of an older child afflicted with leukaemia. Public response from medical ethicists was negative. This paper argues that what the family did was not clearly wrong and that the ethicists should not have made public pronouncements calling the morals of the family into question.
Recently, it has been shown that boar acrosin exhibits a carbohydrate-binding activity with a specificity to fucose, by which it can bind to the oocyte zona pellucida. By limited autoproteolysis of a high-molecular mass acrosin (55/53 kDa), designated as alpha-acrosin, a 15 kDa fragment was generated which interacts strongly with the porcine zona pellucida. Zona-binding was demonstrated on protein blots and by the solid-phase zona-binding assay utilizing biotinylated zona proteins. The zona-binding peptide was isolated by reversed-phase HPLC and analyzed for amino acid sequence. Its single N-terminal sequence corresponded to that of the acrosin B-chain (heavy chain). These data indicate that the zona-binding properties of acrosin are associated with the N-terminal peptide of the acrosin heavy chain.
Acrosin is a multifunctional enzyme combining several functional properties within a single molecule: the catalytic triad of the proteinase, hydrophobic domains responsible for the special membrane-associating character of the enzyme and the carbohydrate binding sites by which the molecule can bind to the zona pellucida. Acrosin occurs in the sperm acrosome as an inactive precursor, proacrosin, with a molecular mass of 53-55 kDa. Proacrosin is activated by a single proteolytic clip between Arg23 and Val24 generating the high molecular mass acrosin. The activation of proacrosin to the biologically active enzyme which occurs concomitantly with the acrosome reaction appears to be regulated on and by the zona pellucida. It is hypothesized that alternating cycles of binding to the zona, digestion of the zona and release from the zona together with the forward motility of the spermatozoon would be required to achieve penetration.
Low-molecular-mass zymogen was extracted from boar spermatozoa together with proacrosin using 10% acetic acid supplemented with 10% glycerol, and was purified by the sequential use of gel filtration on Sephadex G-75 and (FPLC) reversed-phase chromatography. LMM zymogen represented approximately 5% of the latent trypsin-like activity present in the sperm extract. SDS-PAGE indicated a molecular mass of 33 kDa. The zymogen reacted with both mouse monoclonal and rabbit polyclonal antibodies to boar acrosin. Determination of the N-terminal sequence of 34 amino-acid residues revealed its identity with the known N-terminal sequence of boar proacrosin.
Wilhelm Fliess, a Berlin nose and throat surgeon, and Sigmund Freud, the father of psychoanalysis, collaborated to treat one of Freud's earliest patients, Emma Eckstein. The basis for the treatment was their belief in the "Nasogenital Reflex," a widely accepted theory that has disappeared from the literature of otolaryngology. The outcome of Emma's treatment may have profoundly altered the history of psychiatry, by suggesting the role of the unconscious and the existence of the Oedipus complex.
Explore the source record for details and available documents.
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.
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.
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.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A preliminary investigation was conducted to determine the efficacy of a structured skin care regimen to prevent perineal dermatitis in incontinent geriatric psychiatry patients. A 10-week, prospective, clinical trial was conducted (n = 15). Four weeks (weeks 2 to 5) were devoted to monitoring the unstructured pretreatment nursing skin care practice and to determining the incidence of perineal dermatitis in incontinent patients. Four weeks (weeks 7 to 10) were also spent implementing and observing the structured nursing skin care regimen. The study revealed that 33% (three) of the subjects in the unstructured skin care group and 33% (two) of the subjects in the structured skin care group had perineal dermatitis. In subjects with a combination of urine and stool incontinence perineal dermatitis developed within 2 days. The findings suggest that perineal dermatitis occurs quickly in the presence of urine and stool incontinence. Further research is needed to validate the efficacy of a structured skin care regimen to prevent perineal dermatitis.