Search PubMed⌕ Search

Biomedical subjects

J Rapp

Publications and source records attributed to J Rapp.

52 records · Page 3Linked to original sources

[Earth currents as a cause of fry losses in a trout stock].

The grounding of the mains by the energy suppliers causes sporadic alternating earth currents. From water over the housings of areator and its earth-connected guardwire such currents may occur. In a South German trout hatchery these earth currents led to losses of 30% among the influenced fry and to a 25% crippling among the surviving fry. Cause, clinical events and possible preventive measures are discussed.

Animals↗

Cholecystokinin cholescintigraphic findings in the cystic duct syndrome.

Fourteen patients with a cystic duct syndrome (CDS) underwent cholecystokinin (CCK) cholescintigraphy. All patients presented with persistent postprandial right upper quadrant pain and biliary colic. None of the patients had an abnormal oral cholecystography, gallbladder (GB) ultrasound exam or upper GI series. Each patient (NPO after 12 a.m.) received 5 mCi of technetium-99m disofenin. When the GB maximally filled, 0.02 microgram/kg CCK was administered (3 min) intravenously. Background corrected gallbladder ejection fractions (GBEFs) were determined every 5 min X 4 by rationing the pre-CCK GB counts minus post-CCK GB counts to pre-CCK GB counts. GBEFs were: 12% (3 patients), 17% (2), 0%, 1.3%, 3%, 4%, 6%, 11%, 14%, 18.5%, and 22% (1 each). All patients underwent a surgical exploration and all had macro- or microscopically abnormal cystic ducts (five fibrotic, seven elongated and narrow, two kinked) with (12 patients) or without (2 patients) concomitant chronic cholecystitis. No patient with a partially occluded cystic duct with or without concomitant chronic cholecystitis had an ejection fraction that exceeded 22%. In an appropriate clinical setting, a low EF response to CCK should alert the physician to the presence of either chronic acalculous cholecystitis, CDS, or the combination of both.

Adolescent↗

Inhibition of aldosterone production by an atrial extract.

Crude extracts of rat atria reduced the basal amount of aldosterone released from rat zona glomerulosa cells and partially inhibited aldosterone stimulation by adrenocorticotropic hormone and angiotensin II. The destruction of this activity by trypsin suggests that the active factor is a peptide, possibly atrial natriuretic factor. These data suggest that atrial natriuretic factor affects sodium excretion by the kidneys both directly and through the inhibition of aldosterone production.

Adrenocorticotropic Hormone↗

Isolation and identification of biologically active contaminants from soft contact lenses. I. Nicotine deposits on worn lenses.

A method for elution of contaminants deposited onto soft contact lenses during wear utilizing a nondestructive cleaning procedure is presented. Twenty-five soft contact lenses supplied by American Optical Corp. were pooled and subjected to 20% H2O2 (hydrogen peroxide). The resulting wash was extracted with organic solvents, hydrolyzed, and re-extracted. The organic-soluble fraction was further divided into strong acids, intermediate acids, neutrals, and bases. Sequential separation, isolation, characterization, and confirmation of constituents were achieved with thin-layer chromatography, ultraviolet spectrophotometry, and microcrystallography. Photomicrographs before and after cleaning were obtained to assess the optical quality of the lenses. Initial emphasis has been to characterize naturally occurring, biologically active constituents and common environmental toxins of molecular weight 150 to 500. We find that nicotine, a common environmental pollutant and a significant component of the blood of people who smoke regularly, is one of the contaminants present on a worn soft contact lens.

Chemistry, Organic↗

Nutrition in the vision of children.

The first section of this paper reviews some of the effects of fetal and postnatal nutritional status on central nervous system development. It is seen that early malnutrition can be an important determinant of visual performance in children. The second section described the key role of vitamin A in the visual process. The consequences of primary and secondary vitamin A deficiencies are considered. The third section discusses some effects of diet on vision, including the role of the B vitamins and vitamin C.

Ascorbic Acid↗

Protein deposits on individual hydrophilic contact lenses: effects of water and ionicity.

Chemical procedures have been developed for eluting deposits from individual hydrophilic contact lenses using combinations of solvents. Total protein was determined as a function of the FDA-proposed classification system for hydrogel lenses. Group IV lenses (high water content, ionic matrix polymers) contained the greatest amount of protein deposits, while group I lenses (low water content, non-ionic polymers) contained the least. Group II lenses (high water content, non-ionic polymers) showed an affinity for protein greater than groups I and III (low water content, ionic polymer) but significantly less than group IV. The necessary basic conditions for maximal protein contamination of hydrophilic contact lenses seems to be created through a combination of an ionic polymer existing in a polar, high water content milieu.

Contact Lenses, Hydrophilic↗

Development of the Abbott AxSYM Free PSA assay: performance characteristics and preliminary clinical evaluation.

The AxSYM Free PSA assay was demonstrated to have good analytical sensitivity and reproducibility. The F/T ratio determinations for 385 men tested during the Prostate Awareness Week who had biopsies due to an elevated total PSA value and/or a suspicious DRE demonstrated that the percentage of free PSA was lower in patients found to have prostate cancer than those that were biopsy negative for the overall group and for all patient categories examined. The optimal strategy for combining PSA values, F/T ratios, DRE and other clinical and diagnostic parameters to improve the early detection of prostate cancer requires additional clinical studies.

Humans↗