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Biomedical subjects

R Babcock

Publications and source records attributed to R Babcock.

9 recordsLinked to original sources

Comparative evaluation of chlamydiazyme, PACE 2, and AMP-CT assays for detection of Chlamydia trachomatis in endocervical specimens.

We conducted a comparative evaluation of the Chlamydiazyme (Abbott Laboratories), PACE 2 (Gen-Probe), and AMP-CT (Gen-Probe) assays for the detection of Chlamydia trachomatis in endocervical samples. Specimens from 787 females were included in the study. The sensitivities of the PACE 2 and Chlamydiazyme assays in comparison to the results of the AMP-CT assay were 79.3 and 63.4%, respectively. The specificities of the Chlamydiazyme and PACE 2 assays were 100%. All of the positive specimens detected in this study were positive by the AMP-CT assay. On the basis of the final results of the comparison, the prevalence of C. trachomatis in the population was 10.4%. Retesting of specimens whose results were in the intermediate zone by the PACE 2 assay by a probe competition assay identified some additional true-positive specimens. Amplification assay testing of such specimens did not significantly increase the yield. The majority of specimens which tested positive by the AMP-CT assay only were not in the intermediate zone by the PACE 2 assay. We were unable to identify demographic or clinical factors which could predict those individuals who tested positive by amplified tests but not by nonamplified tests. The Gen-Probe PACE 2 assay proved to be superior to the Chlamydiazyme assay for the screening and diagnosis of C. trachomatis infections in female endocervical specimens.

Adult↗

Synchronous multispecific spawning on coral reefs: potential for hybridization and roles of gamete recognition.

Problems of gamete recognition in corals and other mass-spawning invertebrates are potentially great. In 'mass spawnings', closely-related species or genera commonly spawn at the same time, or within 1 or 2 h of each other, increasing the potential for hybridization. Among mass-spawning corals, most of the species involved are hermaphrodites that package the gametes in buoyant bundles that float to the sea surface before breaking up. Local hydrodynamic features frequently act to aggregate gametes from many different species into slicks where both eggs and sperm can be viable for extended periods. Other mass-spawning invertebrate taxa, such as molluscs, polychaetes and various echinoderms, do not have buoyant gametes but also spawn with a high level of synchrony. Gametes of organisms participating in these spawning events must be able to successfully recognize conspecifics. If they cannot do this, either through sperm chemotaxis or by mechanisms at the level of sperm binding and penetration, there may be high levels of gamete wastage through hybridization. Alternatively, viable hybrids may be formed, a factor that could have contributed to the evolutionary history of mass-spawning taxa, as well as to the taxonomic difficulties that have plagued the taxonomy of groups such as reef-building corals. Within some mass-spawning taxa, pre-zygotic barriers to fertilization suggest relatively recent molecular evolution at gamete recognition loci.

Animals↗

Renal function in critically ill postoperative patients: sequential assessment of creatinine osmolar and free water clearance.

Sequential assessment of renal function in 50 critically ill postoperative patients was done by simultaneous determinants of osmolar, free water, creatinine and sodium clearances, and fractional excretion of sodium. The traumatic and nontraumatic critically ill surgical patients had a characteristic pattern of creatinine clearance (Ccr) which was age related. This was manifested in the trauma patient by Ccr which were initially greater than expected (140-190 ml/min.1.73 M2). In the uncomplicated postoperative patients, a positive correlation was found between increased cardiac index and the indexed glomerular filtration rate. Decreases in free water clearance and Ccr were useful in predicting the onset of renal failure before the development of the oliguric state. The authors conclude that frequent assessment of those renal functions which are most adversely affected by accidental or surgical trauma is most appropriately monitored by serial measurement of creatinine and free water clearance.

Acute Kidney Injury↗

Linolenic acid deficiency.

Linolenic acid deficiency has not been demonstrated clearly in warm blooded animals, yet circumstantial evidence suggests that n-3 fatty acids may have functions in these animals. The fact that several species of fish definitely require dietary n-3 fatty acids indicates that n-3 fatty acids have important and specific functions in these animals and suggests that such functions may also be present in warm blooded animals. It is also true that n-3 fatty acid distribution in tissues of birds and mammals appears to be under strict metabolic control, and that this complex metabolic control mechanism apparently has survived evolutionary pressure for a very long time. So far, attempts to produce linolenic acid deficiency in mammals have not revealed an absolute requirement for n-3 fatty acids. If functions for n-3 fatty acids do exist in warm blooded animals, it seems probable that they may be located in the cerebral cortex or in the retina, because these tissues normally contain high concentrations of n-3 fatty acids.

Animals↗

Linolenic acid deficiency: changes in fatty acid patterns in female and male rats raised on a linolenic acid-deficient diet for two generations.

Rats were fed for two generations a purified, linolenic acid-deficient diet in which the only source of lipid was purified methyl linoleate. This diet contained about 38 mg linolenic acid/kg diet. Control rats were given the same diet supplemented with methyl linolenate (2,500 mg/kg diet). Male and female rats ranged in age from weaning pups to adults. Lipids were extracted from liver, brain, kidney, spleen, heart, muscle, gastrointestinal tract, lung, ovary, testis, adrenal, plasma, erythrocytes, retina, and adipose tissue. Fatty acids of major phospholipid classes (choline phosphoglycerides, ethanolamine phosphoglycerides, and mixed serine phosphoglycerides plus inositol phosphoglycerides) or of total lipid extracts were measured by gas liquid chromatography. Growth rates and organ weights were similar in control and linolenic acid-deficient rats. The major effect of the deficiency was to lower the proportions of n-3 fatty acids, especially 22:6 n-3, in all the organs analyzed. Docosahexaenoic acid (22:6 n-3) was mainly replaced by 22:5 n-6 in deficient rats. The greatest changes in composition were found in brain, heart, muscle, retina, and liver.

Age Factors↗