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Biomedical subjects

L M Boylan

Publications and source records attributed to L M Boylan.

28 records · Page 2Linked to original sources
PubMed1987

Vitamin B-12 and folate intakes and plasma levels of black adolescent females.

The vitamin B-12 and folate intakes and plasma levels of 39 healthy black female adolescents were evaluated. Estimated dietary folate intakes of 97% of the subjects were less than 2/3 of the RDA, and 74% had plasma folate levels indicative of marginal (3.0 to 5.9 ng/ml [less than 6 nmol/:]), nmol/L]), and 3%, deficient (below 3.0 ng/ml [less than 6 nmol/L]) folate status. Thirteen percent of the subjects had estimated dietary intakes below 2/3 of the RDA for vitamin B-12; all subjects had plasma levels indicative of adequate vitamin B-12 status.

Adolescent↗
PubMed1985

Psychological and attitudinal profiles in donors for artificial insemination.

Few objective data are available concerning the psychological profiles and attitudes of sperm donors in artificial insemination programs. We studied 30 consecutive new volunteers and 45 established sperm donors using the Cattell 16PF personality profile and an attitudinal survey concerning motives for donation, attitudes toward uses of sperm, desire for knowledge of outcomes, and attitudes toward disclosures of identifying and nonidentifying information between the parties to artificial insemination. Donors differed from the population norms in 7 of 16 first-order and 1 of 4 second-order personality factors, and this difference appeared to reflect their self-selection as donors. The predominant motive for donation was altruism, but secondary motives were also common. Financial motivation was very low in this population with few students. Donors approved of all current and most hypothetical uses of sperm but were not in favor of disclosures of information to other participants in the program. Restriction of disclosures to nonidentifying details was more acceptable. Unmarried donors were more often motivated for nonaltruistic reasons and were more in favor of disclosures. Attitudes of sperm donors were mostly stable over at least 3 years, but an increasing minority with time envisaged circumstances that might lead to their withdrawal from the program.

Attitude↗
PubMed1984

Young's syndrome. Obstructive azoospermia and chronic sinopulmonary infections.

We studied 29 men with Young's syndrome, a combination of obstructive azoospermia and chronic sinopulmonary infections. Men with this syndrome have only mildly impaired respiratory function and normal spermatogenesis; the azoospermia is due to obstruction of the epididymis by inspissated secretions. The diagnosis is based on the occurrence of chronic sinopulmonary infections, persistent azoospermia, normal spermatogenesis, and characteristic epididymal findings, as well as exclusion of cystic fibrosis and the immotile-cilia syndrome. The sperm themselves appear to be normal in Young's syndrome. Pregnancies had occurred in five couples; in three paternity was documented by genotyping. Thus, improved microsurgical and medical therapy might restore fertility. We suggest that Young's syndrome has a prevalence comparable to that of Klinefelter's syndrome and is a common cause of both chronic sinopulmonary infection and azoospermia.

Adult↗
PubMed1984

Testicular function in potential sperm donors: normal ranges and the effects of smoking and varicocele.

Testicular exocrine (semen analysis) and endocrine (plasma LH, FSH, prolactin and testosterone) function was assessed in 119 consecutive healthy men presenting for screening as potential sperm donors. Since these volunteers were unbiased with respect to their fertility status, this sample of the general male population was suitable to determine normal ranges and the influence of a variety of physical (height, weight, standardized body weight, varicocele) and demographic (age, marital and fertility status, tobacco and alcohol consumption) factors on normal human testicular endocrine and exocrine function, without the confounding effects of bias in selection of subjects. The statistical distribution of all seminal parameters was non-gaussian, but cube-root transformation of the data normalized the distribution, allowing for parametric statistical analysis. The median (and 95% confidence limits) for the various semen parameters was 73.0 (10.6-235.3) million sperm per ml; 189.0 (12.6-868) million sperm per ejaculate; 50.4 (5.9-181.9) million motile sperm per ml; 133.0 (6.9-661.7) million motile sperm per ejaculate; 54.0 (7.0-172.9) million morphologically normal sperm per ml and 138.5 (7.5-672) million morphologically normal sperm per ejaculate. Testicular volume was correlated positively with measures of physique such as standardized body weight (r = 0.25, P less than 0.01) and body surface area (r = 0.30, P less than 0.002), and negatively with plasma levels of FSH (r = -0.31), P less than 0.002) but not LH. Sperm output was positively correlated with testicular volume (r = 0.28, P less than 0.005) and negatively correlated with plasma FSH (r = -0.31, P less than 0.002) and plasma LH (r = -0.31, P less than 0.002). Smoking was associated with a highly significant reduction in sperm output and motility. Men with varicocele (25%) were significantly taller, had slightly lower haemoglobin levels and moderate left (but not right) testicular atrophy, but neither seminal nor hormonal parameters were different from men without varicocele. There was no difference in any markers of human testicular function between men according to marital or fertility status, grades of moderate alcohol consumption or the presence of low titres of sperm antibodies.

Adult↗
PubMed1984

Pharmacokinetics of gonadotropin-releasing hormone: comparison of subcutaneous and intravenous routes.

Pulsatile administration of GnRH has been used to stimulate gonadal function in both hypogonadotropic men and women; however, deficient responses were observed with the sc in contrast to the iv route of hormone delivery. To clarify whether this was due to altered bioavailability, we compared the pharmacokinetics of these two routes of GnRH administration by bolus injection and steady state continuous infusion methods. Synthetic GnRH was administered by both sc and iv routes to 14 hypogonadotropic patients (11 women and 3 men) as a bolus (5 micrograms in 25, 100, or 250 microliters, sc, and 250 microliters, iv; n = 6) or by continuous iv or sc infusion (3.17 micrograms/h for 6 h; n = 11). In single dose studies, plasma immunoreactive GnRH (IR-GnRH) peaks were earlier and higher (400 vs. 93.5 pg/ml) and returned to baseline sooner (less than 60 vs. greater than 120 min) after iv than after sc bolus injection. Plasma IR-GnRH levels were lower between 1 and 5 min, but higher between 30-90 min after sc injection compared with iv bolus injection. During the continuous infusions, plateau levels of IR-GnRH between 2 and 6 h were 34% lower with sc delivery (67.5 vs. 102.4 pg/ml), indicating irreversible losses of about one third of GnRH injected sc. In patients undergoing pulsatile GnRH therapy delivered by programmed portable minipumps, plasma IR-GnRH profiles were highly damped after sc administration, but retained an intermittent pulse wave form with the iv route. These data suggest that pharmacokinetic differences in the sc and iv routes of GnRH administration are due to a combination of prolonged and delayed absorption with reduced bioavailability of GnRH via the sc route. The consequent damping of the plasma GnRH profiles with sc administration may contribute to differences in the clinical efficacy of pulsatile GnRH regimens, and specific modifications of pulsatile regimens may be required to adapt the physiological requirements of an intermittent plasma GnRH wave form to the damped and reduced bioavailability of sc GnRH therapy.

Adult↗
PubMed1983

Reactions to intravenous contrast media. Part I: Severe and fatal cardiovascular reactions in a canine dehydration model.

Investigations into the nature of severe and fatal reactions to contrast media have been severely limited by their unpredictable occurrence in the clinical setting and the absence of suitable laboratory models. The authors report their experience with a canine dehydration model. Intravenous administration of 2 ml/kg of 76% sodium methylglucamine diatrizoate resulted in vomiting, shock, inappropriate slowing of the heart rate, and death. ECG findings indicated suppression of sinoatrial node automaticity, a decrease in the rate of atrioventricular conduction, and depression of myocardial contractility. These results suggest two possible mechanisms: (a) enhanced vagal tone as the result of stimulation of the vasomotor center of the medulla or (b) accentuation of direct contrast-induced myocardial toxicity.

Animals↗
PubMed1983

Reactions to intravenous contrast media. Part II: Acute renal response in euvolemic and dehydrated dogs.

Growing concern about acute renal failure as the result of contrast agents prompted an investigation into the renal effects of intravenous contrast materials in euvolemic and dehydrated dogs. Bolus injection of hypertonic agents induced marked reductions in filtration fraction and glomerular filtration rate in both groups of animals; however, these changes were transient, returning to near-base-line values within 30 minutes after injection. The most striking differences between euvolemic and dehydrated animals appeared to be related to prerenal factors such as hypovolemia and contrast-induced hypotension.

Animals↗
PubMedDate not supplied

Testicular function and glycemic control in diabetic men. A controlled study.

We have investigated testicular function in 28 insulin-dependent diabetic men under the age of 50 years and 119 age-matched controls. Diabetics had reduced testicular volume, semen volume, total and total motile sperm output while plasma LH and FSH levels were elevated. Reduction in semen volume and impotence were more common in long-standing complicated diabetes. Glycosylated hemoglobin (GHb) levels were positively correlated with plasma LH levels (r = 0.46, p less than 0.02) but there was no direct correlation of glycemic control and spermatogenesis. The differences in testicular function were due to decreased spermatogenesis and could not be explained by other forms of testicular pathology or the presence of diabetic neurovascular complications. We conclude that the function of the hypothalamic pituitary testicular axis is impaired in diabetic men, that this impairment is at least partly related to the degree of preceding glycemic control and that multiple levels of the axis may be dysfunctional.

Adult↗
PubMedDate not supplied

Testicular function and fertility in men with homozygous alpha-1 antitrypsin deficiency.

Fertility and testicular function were studied in eight men with severe homozygous (Pi ZZ variant genotype) alpha-1 antitrypsin (AAT) deficiency. Age- and marital duration standardized fertility, clinical androgenic features, mean testicular volume, plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and semen analysis were all normal apart from a reduction in semen volume. Mean plasma total and free testosterone were elevated and the percentage free testosterone reduced compared with age-matched, healthy fertile controls indicative of increased sex-hormone binding globulin (SHBG) levels representing an early marker for subclinical hepatic dysfunction associated with AAT-deficiency. In view of the preservation of normal fertility and testicular function despite chronic respiratory disease and premature death with deleterious AAT gene variants, it is proposed that the high prevalence of genetic polymorphism in the AAT protein may be maintained by the chronological asynchrony of the periods of maximal male reproductive activity (40 years) and the late onset (greater than 40 years) of symptoms in severe AAT deficiency rather than by any balance between reduced reproductive fitness of homozygotes and heterozygote advantage.

Fertility↗