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Biomedical subjects

R H Foote

Publications and source records attributed to R H Foote.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Quantification of bovine sperm separation by a swim-up method. Relationship to sperm motility, integrity of acrosomes, sperm migration in polyacrylamide gel and fertility.

The number of bovine spermatozoa separated in a swim-up procedure was quantified using an electronic cell counter. In an initial test of the swim-up procedure, non-frozen sperm samples with different ratios of live to dead cells were prepared and tested for the number of spermatozoa counted by the swim-up procedure. In ejaculates from six bulls, the number of spermatozoa swimming up was related to the number of live cells present (R2 = 0.97). Next, sperm quality of frozen-thawed semen immediately after thawing was measured at 37 C by swim-up sperm count, sperm motility, spermatozoa with an intact acrosome and migration in polyacrylamide gel and then compared with the fertility of the semen used for artificial insemination. Twenty-nine ejaculates of frozen-thawed semen from 11 bulls were evaluated. Correlations with fertility were highest on an ejaculate basis for motility (r = 0.41, P = 0.05) and for swim-up sperm count (r = 0.35, P = 0.06). On a bull basis, swim-up sperm count had the highest correlation with fertility (r = 0.59, P = 0.06). In a multiple regression model to predict male fertility that included all described measures of semen quality, a R2 value of 0.69 was obtained. This is the first report showing that the ability of spermatozoa to swim out of a more dense medium (whole milk-glycerol extender) into culture media is quantitatively related to in vivo fertility.

Acrosome↗
PubMedDate not supplied

Ethylene glycol monomethyl ether effects on health and reproduction in male rabbits.

Male Dutch rabbits were weighed and randomly assigned within each weight group to five groups of six animals each (plus one more in the highest dose group). They received 0, 12.5, 25.0, 37.5, or 50.0 mg of ethylene glycol monomethyl ether (EGME) per kg of body weight in the drinking water 5 d/week for 12 weeks. Feed and water consumption were monitored daily and body weight weekly. All animals consumed the water and feed, maintained body weight, and were in good health throughout the experiment. Semen was collected twice weekly for 12 weeks, and 96% of the ejaculates were obtained. By weeks 6 and 9, most males in groups receiving 50.0 or 37.5 mg of EGME per kg were oligospermic. Only minor changes in other characteristics of sperm obtained from treated animals were found, as measured by computer-assisted sperm analysis. Fertility of the males still producing sufficient sperm during week 12 to use for insemination was tested with 96 does producing 2839 oocytes, and fertility of treated males (41%) was not lower (P > 0.05) than 47% in controls. At necropsy, all vital organs were grossly normal, with no notable histopathology. However, the groups of animals receiving 37.5 and 50 mg of EGME per kg of body weight produced fewer sperm and had smaller testes than controls (P < 0.05). Although all rabbits appeared grossly normal, there was a marked disruption of spermatogenesis as ingestion of EGME increased above 25 mg/kg of body weight. Rabbit testes appear to be more sensitive to EGME than testes of rats or mice.

Animals↗
PubMedDate not supplied

Methods for assessing sperm motility, morphology, and counts in the rat, rabbit, and dog: a consensus report. ILSI Risk Science Institute Expert Working Group on Sperm Evaluation.

Reproductive toxicity studies are increasingly including assessments of sperm parameters including motility, morphology, and counts. While these assessments can provide valuable information for the determination of potential reproductive toxicity, the methods for conducting the assessments have not been well developed in all laboratories and are continually evolving. The use of different methods in different laboratories makes comparison of data among laboratories difficult. To address the differences in methods, a working group was convened to discuss methods currently in use, share data, and try to reach consensus about optimal methods for assessing sperm parameters in rats, rabbits, and dogs. This article presents the consensus report, as well as future research needs, with the hope that optimized common methods will aid in the detection of reproductive effects and enhance interlaboratory comparisons.

Animals↗
PubMedDate not supplied

The rabbit as a model for reproductive and developmental toxicity studies.

The rabbit has many advantages as a nonrodent and second model for assessing the effects of toxic agents on semen quality, fertility, developmental toxicity, and teratology. The male and female reproductive systems of the rabbit are described, and data on growth, sexual development and reproduction are compared with mice, rats, and humans. Techniques for semen collection and evaluation in the male, and artificial insemination, superovulation, embryo culture, and embryo transfer in the female are included as useful procedures in toxicity testing. Examples of the use of rabbits and experimental replication for toxicity testing are given. Special features of the visceral yolk sac and development of the chorioallantoic placenta of the rabbit are compared with rodents. The rabbit extraembryonic membranes more closely resemble the human than do the rodents, in some respects. The use of the rabbit in developmental toxicity and teratology studies is discussed.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Disruption of spermatogenesis in rabbits consuming ethylene glycol monomethyl ether.

Effects of ethylene glycol monomethyl ether (EGME) on spermatogenesis were examined using groups of six to seven Dutch rabbits that received 0, 12.5, 25.0, 37.5, or 50.0 mg of EGME/kg body weight, respectively, in their drinking water 5d/week. After 12 weeks, animals were euthanized and their testes were removed, weighed, and processed to permit germ cell numbers to be quantified. Spermatogenesis was depressed by EGME in a dose-dependent manner; numbers of round spermatids per Sertoli cell (a measure of spermatogenic efficiency) averaged 8.86, 8.87, 6.20, 2.38, and 7.42 for the 0, 12.5, 25.0, 37.5, and 50.0 mg/kg dosages, respectively. The latter value of 7.42 represents an overestimation of sperm production because it is based on only two unexpected outlier rabbits. Nearly complete destruction of spermatogenesis occurred in the other five animals in this highest dosage group, precluding evaluation by the histometric method. Numbers of homogenization-resistant elongated spermatids per testis, measurable on all animals, averaged 231, 256, 195, 52, and 67 x 10(6), respectively. The correlation between the predicted sperm production, based on the elongated spermatids at necropsy, and the number of sperm ejaculated by the males during week 12 was 0.92. Thus, EGME impaired rabbit spermatogenesis in a dose-dependent manner. Generally, rabbit spermatogenesis was at least 10 times more sensitive to EGME than previously reported for rats and mice.

Animals↗
PubMedDate not supplied

Cadmium affects testes and semen of rabbits exposed before and after puberty.

Semen quality and testicular characteristics were measured in 92 rabbits in three controlled experiments with males exposed to cadmium chloride (Cd) when 12 or 27 weeks old. Doses of Cd were administered subcutaneously (s.c.), orally, or intravenously (i.v.) and subsets of animals were unilaterally castrated or not to evaluate the testes and to collect semen repeatedly from males when adults. There was considerable variability but Cd given at 12 weeks of age in doses of 0.08 mmol/kg s.c., 0.20 mmol/kg orally, and 0.02 mmol/kg i.v. tended to depress sperm output of these males when adults. The 0.02 mmol/kg dose given i.v., 0.4 mmol/kg orally, and 0.16 mmol/kg s.c. were lethal to many animals. Treatment of adults resulted in a generally similar pattern of systemic toxicity, and limited comparisons suggested that testicular sensitivity was slightly less than for young males. Androgenic function usually was maintained, as indicated by normal libido and seminal volumes even in males with reduced spermatogenesis. Necropsies confirmed previous findings of hyperemia, hemorrhaging, necrosis, and destruction of all spermatogenic elements in severely affected males.

Administration, Oral↗
PubMedDate not supplied

Fertility of rabbit sperm exposed in vitro to cadmium and lead.

The heavy metals Cd2+ and Pb2+ have been associated with male reproductive toxicology, including possible inhibition of sperm undergoing hyperactivated motility, indicative of capacitation. The objective of the present study was to test fertility of rabbit sperm exposed to Cd2+ or Pb2+ in vitro, followed by insemination of superovulated does. Semen was washed to remove seminal plasma and minimize possible binding of the heavy metals by proteins. Only 400,000 treated or control sperm were inseminated as a sensitive test of treatment, and the time sperm resided in the female before possible fertilization was varied by inseminating from 0 to 12 h after ovulating the does. Only 6 of 22 males tested showed appreciable spontaneous hyperactivation and neither Cd2+ nor Pb2+ affected hyperactivation, or presumably associated capacitation. Sperm from four of these six males were used to inseminate 66 rabbits, and 1483 oocytes and embryos were collected about 27 h later. No effect of 0.1 mM Cd2+ on fertilizing ability of sperm was found (75% fertilization with control sperm and 78% with treated sperm). With 0.025 mM Pb2+ the fertilization rate in pregnant does only was 82% for controls and lower (68%) with treated sperm. These tested concentrations of Cd2+ and Pb2+ are much higher than reported concentrations in semen of exposed workers.

Animals↗