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Biomedical subjects

M L Smith

Publications and source records attributed to M L Smith.

At least 451 records · Page 25Linked to original sources
PubMed1979

In vivo rate of serotonin synthesis in brain and spinal cord of young, spontaneously hypertensive rats.

The accumulation of 5-hydroxytryptophan (5-HTP) following decarboxylase inhibition was measured in hypothalamus (HYP), pons-medulla (PM) and spinal cord (SC) of 4- and 8-week-old spontaneously hypertensive (SH) and normotensive (WKY) rats. Using this method, a significant increase in the in vivo activity of tryptophan hydroxylase was observed in the PM and SC of 4-week-old, but not 8-week-old SH rats. These findings show a transient elevation in rate of 5-HT synthesis prior to the onset of hypertension, which does not appear to continue during the maintenance phase.

Animals↗
PubMed1979

Seminal immunoreactive prolactin before and after vasectomy.

Seminal fluid was assayed for prolactin by radioimmunoassay in eleven healthy males 8-12 weeks following vasectomy. The results were compared with those obtained in 34 age matched subjects prior to undergoing vasectomy. The mean values (+/- 1 SD) for prolactin were similar (postvasectomy = 11.4 +/- 3.2 ng/ml, prevasectomy = 12.7 +/- 6.1 ng/ml) and there was no statistically significant difference (t = 0.66, P = greater than 0.05). This study shows that prolactin is found in secretions of the prostate and/or seminal vesicles.

Adult↗
PubMed1979

Comparison of prolactin levels in human semen and seminal plasma.

Semen samples were collected from 35 men and the levels of prolactin in semen and seminal plasma were measured. There was no significant difference in prolactin concentrations between the two fluids (t = 0.333, P greater than 0.7). There was also no correlation between the prolactin concentration and the kinematic viscosity of the semen (r = 0.065, P greater than 0.7).

Adult↗
PubMed1979

Cell cycle phase-specific cytotoxicity of the antitumor agent maytansine.

The objective of this investigation was to study the effects of maytansine on the cell cycle kinetics of HeLa cells. The results of this study indicate that maytansine is a very potent mitotic inhibitor and that it has no effect on macromolecular synthesis. Maytansine-induced cytotoxicity was dependent upon the position of the cell in the cell cycle. Mitotic and G2 cells are most sensitive to this agent, while G1 phase cells are the most resistant, with S-phase cells being intermediate. Small (0.82 X 10(-8) M) fractionated doses given at an interval of 8 hr have been found to be more cytotoxic than was a large (1.63 X 10(-8) M) single dose. In evaluating the drug combinations, we observed that the schedule in which 1-beta-D-arabinofuranosylcytosine treatment was followed by maytansine treatment exhibited greater cell kill than the reverse sequence. No schedule-dependent effects were observed when maytansine was tried in combination with Adriamycin.

Cell Cycle↗
PubMed1979

Correlations between seminal radioimmunoreactive prolactin, sperm count, and sperm motility in prevasectomy and infertility clinic patients.

Semen samples were collected from 50 prevasectomy patients and 43 infertility clinic patients. Various parameters were measured, including semen radioimmunoreactive prolactin (rPRL) levels. Linear correlations were tested between the measured parameters, and a significant correlation was found between semen rPRL concentration and sperm count for both the prevasectomy (r = 0.73, P less than 0.00002) and the clinic patients (r = 0.72, P less than 0.00002). For the clinic patients a correlation was also found between the amount of ejaculate rPRL and sperm motility (r = 0.46, P less than 0.002) and between ejaculate volume and motility (r = 0.36, P less than 0.02).

Adult↗
PubMed1979

Tissue testosterone and dihydrotestosterone from bilateral testis biopsies in males with varicocele.

Nine males with varying degrees of subfertility with left varicocele underwent bilateral testicular biopsy for determination of testicular testosterone (T) and dihydrotestosterone (DHT) content. Testicular tissue T and DHT levels varied greatly, and there was no significant difference when the group T and DHT content of the left testis was compared with that of the right testis. When the respective mean preoperative sperm count was compared with the bilateral tissue T and DHT content, no consistent relationship was found.

Adult↗
PubMed1978

Reference ovine serum chemistry values.

Twenty-five serum chemistry values were determined on 18 female sheep. These average values were obtained using current semiautomated analytical techniques, with all enzyme measurements reported in international units. Where possible, these results were compared with those of 4 other investigators. This compilation will provide a set of reference values which can be used for comparison with results obtained from current commercial clinical laboratories.

Animals↗