Biomedical subjects

R A Tom

Publications and source records attributed to R A Tom.

5 recordsLinked to original sources

PubMed1990

Optimizing the sperm penetration assay with human follicular fluid.

Major limitations of the conventional sperm penetration assay are the inability to assess several aspects of sperm function (zona binding and penetration) and the absence of human ovulatory products known to influence fertilization. We therefore modified the sperm penetration assay by the addition of human follicular fluid (FF) to induce the acrosome reaction in an attempt to improve the false-negative rate of the conventional technique. In 26 patients with negative results, results became positive in 20 with human FF and the acrosome reaction increased fourfold. In 19 different men, we compared the results of the conventional and modified assays with outcome of in vitro fertilization. The false-positive rate was the same, but the false-negative rate was reduced from 40% to 7% with the addition of human FF.

Acrosome↗

PubMed1989

Assessment of male infertility: correlation between results of semen analysis and phosphorus-31 magnetic resonance spectroscopy.

To evaluate the usefulness of phosphorus-31 magnetic resonance spectroscopy (31P-MRS) in assessing male infertility, we compared it with conventional semen analysis. Specimens were obtained from otherwise healthy patient groups as follows: group A, 7 fertile control subjects; group B, 12 azoospermic men after vasectomy; and group C, 11 patients presenting for infertility evaluation. Correlations between established semen analysis parameters and the 31P-MRS-derived ratio of glycerylphosphorylcholine to total phosphate (GPC/TP) were investigated. Group A controls had a mean GPC/TC ratio of 0.10 +/- 0.05, which was the same as that of group C. With the exception of significantly lowered motility and normal morphology in group C (p less than 0.001 and 0.05, respectively) semen analysis parameters in these two groups were similar. In contrast, the GPC/TP ratio in group B (0.05 +/- 0.04) was significantly different from the control (p less than 0.05), which appropriately reflected complete vasal occlusion. The results suggest that a significant portion of seminal GPC is derived from epididymal secretion and that 31P-MRS is useful for monitoring the GPC/TP levels when assessing epididymal function and male infertility.

Glycerylphosphorylcholine↗

PubMed1989

SpermCheck: a simplified screening assay for immunological infertility.

SpermCheck (Bio-Rad Laboratories, Hercules, CA), a new screening test for regional surface antibodies on motile sperm, uses monodispersed latex microspheres of uniform size as a vehicle to link rabbit antihuman immunoglobulins (IgA, IgG, IgM) and provides both negative and positive control sera, as well as sufficient buffer for sperm preparation in ambient CO2 atmosphere. When compared with reference data available for the immunobead test (IBT), the direct protocol (semen) for SpermCheck yielded 94.4% sensitivity with 100% specificity; the indirect protocol (serum) provided a sensitivity of 100% with 94.7% specificity. The microspheres of SpermCheck maintain a nearly uniform concentration per volume, with none to negligible clumping. The greater difference between the optical densities of latex and cytoplasm allows use of a light microscope for the rapid assessment of the percent of regional binding rather than the phase-contrast microscope required for the IBT. SpermCheck eliminates many difficulties encountered with the IBT, making SpermCheck a convenient screening assay for use in the physician's office.

Antibodies↗

PubMed1982

Experimental studies of rapid sperm transport in rabbits.

When non-motile spermatozoa were used in seminal plasma for artificial insemination, rapid sperm transport to that oviducts was observed in every animal examined 15 min after insemination. Rapid transport never occurred when non-motile spermatozoa were suspended in artificial media, but when motile spermatozoa were suspended in artificial media they were frequently recovered from the oviducts within 15 min. Two successive artificial inseminations 15 min apart were each followed by rapid transport when both inseminates contained seminal plasma; when the second inseminate consisted of spermatozoa suspended in saline, only the first sperm population reached the oviducts. Rapid sperm transport was effectively blocked with the alpha-adrenergic antagonist phenoxybenzamine. We therefore conclude that: (1) sperm motility is not required for rapid sperm transport in rabbits, (2) constituents of the seminal plasma may initiate rapid transport by stimulation of vaginal contractions, (3) independent contractions of the uterus under control of the sympathetic nervous system may continue the transport process once the spermatozoa reach the uterus.

Animals↗

PubMed1975

Assay for lipolytic and proteolytic activity using marine substrates.

Nondestructive assay procedures for determining microbial lipolytic and proteolytic activity on marine substrates were developed and tested with 287 isolates of bacteria, filamentous fungi, and yeasts. A definite substrate specificity was noted when the enzymatic activities on marine and nonmarine substrates was compared. Of 170 lipolytic isolates, 14 were only active on menhaden oil, 11 could hydrolyze menhaden oil and Tween 80 and/or tributyrin, and 145 isolates could only hydrolyze one or both of the nonmarine lipids. Of the 198 proteolytic isolates, 10 were specific for codfish extract, 152 were active against the marine substrate plus casein and/or gelatin, and 36 were specific for nonmarine substrates.

Animals↗