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Biomedical subjects

N J Alexander

Publications and source records attributed to N J Alexander.

At least 145 records · Page 8Linked to original sources
PubMed1977

Cell-mediated immunity in vasectomized rhesus monkeys.

Cell-mediated immunity in rhesus monkeys that had been vasectomized for 2, 4, 7, or 11 years was measured by lymphocyte blastogenesis following stimulation with concanavalin A, phytohemagglutinin (PHA), and pokeweed mitogens. Several of the 7- and 11-year vasectomized animals had significantly reduced PHA reactivity when compared with control animals, and the percentage of animals with reduced PHA reactivity increased with time after vasectomy.

Alpha-Globulins↗
PubMed1977

Reproducibility of the indirect immunofluorescence test on swollen human spermheads.

Sera of 111 vasectomized men and infertile men and women were tested in each of two laboratories with the indirect immunofluorescence test on swollen human spermatozoa to detect antibodies against nuclear antigens specific to sperm. Comparison of the results revealed complete agreement in 110 of the sera. There were seventeen concordant positive sera (eight out of eighteen sera from vasectomized men, eight out of seventeen sera from infertile men, and one out of seventy-six infertile women). Most of the antibodies were of the IgG class.

Antibodies↗
PubMed1977

Vasectomy and vasovasostomy in rhesus monkeys: the effect of circulating antisperm antibodies on fertility.

Rhesus monkeys develop agglutinating and complement-dependent antisperm antibodies after vasectomy. In order to study whether these antibodies affect fertility after vasovasostomy, 15 animals were given vasectomies and 6 months later vasovasostomies. Subsequently, each was mated with females of proven fertility. Five controls were given sham operations and similarly treated. During this period, each aimal was bled for serum to monitor the humoral immune response, ejaculated for semen analyses, and palpated for granuloma or fistula development. All control animals had a transient decrease in sperm density after sham vasectomy and vasovasostomy operations. The surgical procedures of vasectomy and subsequent vasovasostomy resulted in more animals having sperm of poor motility and quality. All of vasovasostomies were surgically successful in that sperm were again present in the ejaculate of each animal. The amount of sperm in the ejaculate could not be correlated with the ease of surgical procedure, presence or absence of macrophages in the ejaculum, motility, or forward progression. Only animals that had been vasectomized developed circulating antisperm antibodies. Sustained, elevated levels of antisperm antibodies most commonly occurred in monkeys that had high initial total sperm counts. Six of the experimental animals retained high levels of sperm-immobilizing antibodies after vasovasostomy. Of these, two were found to be infertile and two were classed as subfertile. Of the nine experimental animals without sustained antisperm antibody production, only one was classed as subfertile. This suggests that antisperm antibodies may in some cases impair the restoration of fertility after vasovasostomy.

Animals↗
PubMed1977

Antigenicity of frozen and fresh spermatozoa.

Since cryopreservation of spermatozoa causes surface changes, we tested whether specific antigens associated with the plasmalemma might be dislodged or destroyed during freezing. When we compared the use of frozen sperm with the use of fresh sperm in indirect immunofluorescence tests for antisperm antibodies, we found changes in antigenicity. There was a decrease in antigenicity of the acrosomal region, and antigenicity of the sperm tail was increased with the addition of 10% glycerol, with or without cryopreservation. These results suggest that women who are infertile and, as demonstrated by immunofluorescence, have antibodies to sperm may be aided by artificial insemination with the husband's cryopreserved sperm.

Antibodies↗
PubMed1976

Sperm antibodies after vasectomy with fulguration.

Whether antisperm antibodies develop after vasectomy probably depends on several variables, 1 of which may be the surgical technique. The levels of serum antisperm antibodies were compared in men vasectomized by 1 techniques: vasoligation and fulguration. No difference in the incidence of spermagglutinating antibody was found in the 2 groups. However, immobilizing antibodies were observed in 43 per cent of the men undergoing vasoligation but in only 29 per cent of the men vasectomized by fulguration.

Agglutinins↗
PubMed1975

Effects of fetal decapitation on the structure and function of Leydig cells in rhesus monkeys (Macaca mulatta).

Fetal decapitation in utero has enabled us to study the role of fetal pituitary hormones in the development of the fetal testis. Testes from males decapitated near 80 days of gestational life and later delivered at 150 days were smaller than normal and about one-tenth the normal weight. The size of the seminiferous tubules was similar in both groups; however, the number of Leydig cells seemed reduced. In addition, the Leydig cells of the experimental group contained smaller mitochondria with reduced tubular cristae, fewer lipid droplets, and reduced agranular endoplasmic reticulum. Androgen production was inhibited. Measured by radioimmunoassay, the testosterone level in the umbilical vein was 329 +/- 82 pg/ml in six decapitates fetuses, 412 +/- 62 pg/ml in ten normal fetuses. The level in the umbilical artery was 328 +/- 56 pg/ml in five decapitated fetuses, 658 +/- 140 pg/ml in normal fetuses. These studies suggest that chronic deprivation of fetal pituitary hormones inhibits the growth and development of the testis in general and of the Leydig cells in particular.

Androgens↗