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Biomedical subjects

J W Overstreet

Publications and source records attributed to J W Overstreet.

At least 19 recordsLinked to original sources
PubMed1992

Effects of maternal exposure to trichloroethylene (TCE) on cell proliferation in the mouse preimplantation embryo.

Pregnant mice were treated with trichloroethylene (TCE) at doses ranging from 0.01 micrograms/kg body weight to 483 mg/kg body weight when embryos were traversing the pronuclear stages of development. No treatment-related effect was seen on total number of embryos recovered from oviducts at the 2 to 4 cell stage of development. The 4-cell embryos were tested for cellular proliferative disadvantage by the embryo chimera assay in which embryos from treated mothers (experimental embryos) are paired with embryos from nontreated mothers (control embryos) to form aggregation chimeras. No significant cell proliferation decreases were observed for any of the experimental embryos across all doses examined.

Administration, Oral↗
PubMed1992

Effects of antibodies to sperm surface fertilization antigen-1 on human sperm-zona pellucida interaction.

OBJECTIVE: To investigate the effects of antibodies to well-defined sperm surface antigens (the fertilization antigen [FA-1] and germ-cell antigen [GA-1]) and nuclear antigen (protamine) on human sperm-zona interaction. DESIGN: Number of total and acrosome-reacted human sperm bound to the human zona pellucida and the sperm movement characteristics assessed by computer-aided sperm analysis were evaluated after incubation of sperm with the antibodies. SETTING: Academic research environment approved by the Institute Review Board. PATIENTS: Human oocytes were obtained from ovaries removed at surgery. Semen from fertile donors was used in all assays. INTERVENTIONS: Human oocytes were stored in salt solution at -80 degrees C until used. Spermatozoa were treated with the antibodies to various sperm antigens. MAIN OUTCOME MEASURES: Total and acrosome-reacted sperm bound to zona pellucida and sperm movement characteristics were evaluated after 3 to 5 hours of incubation of the antibodies with human sperm. RESULTS: Anti-FA-1 antibodies significantly reduced human sperm fusion with zona-free hamster oocytes and sperm binding to the human zona pellucida but did not affect binding of acrosome-reacted sperm and sperm movement characteristics. Anti-GA-1 and antiprotamine antibodies did not affect sperm-oocyte interaction, acrosomal reaction, or sperm motility. CONCLUSIONS: Antibodies to FA-1 but not to GA-1 and protamine inhibit human sperm-zona interaction.

Acrosome↗
PubMed1992

Prospective assessment of early fetal loss using an immunoenzymometric screening assay for detection of urinary human chorionic gonadotropin.

OBJECTIVE: To develop an economical, nonradiometric immunoenzymometric assay (IEMA) for the detection of urinary human chorionic gonadotropin (hCG) in studies of early fetal loss. To be effective, the IEMA must have a sensitivity equal to the standard immunoradiometric assay (IRMA) and sufficient specificity to eliminate the need for screening most nonconceptive cycles with the expensive and labor-intensive IRMA. DESIGN: Two different assays were used to measure hCG in daily early morning urine samples from potential conceptive cycles. SETTING: Women undergoing donor artificial insemination (AI) were evaluated in a prospective study. PATIENTS, PARTICIPANTS: Ninety-two women volunteers were selected on the basis of apparent normal reproductive health. INTERVENTIONS: Artificial insemination with nonfrozen donor semen was performed by cervical cup twice each menstrual cycle at 48-hour intervals, and daily urine samples were self-collected throughout the menstrual cycle. MAIN OUTCOME MEASURES: An IEMA was developed to detect urinary hCG using the same antibodies as in the standard IRMA; a study was designed to determine whether this nonradiometric assay could successfully detect the early fetal loss that was detected by the IRMA. RESULTS: Of 224 menstrual cycles analyzed by both assays, a total of six early fetal losses were detected by the IRMA. When the tentative screening rule was set to allow all six of these losses and 95% of future losses to be detected by the IEMA, an additional 34 false-positive results were detected by the IEMA. The specificity of the IEMA with this rule was calculated to be 84%. CONCLUSION: An IEMA based on the same antibodies used for the standard IRMA can serve as an efficient screening assay for the detection of early fetal loss. When the IEMA is used in this manner, nearly 80% of screened menstrual cycles can be eliminated without further testing by the IRMA.

Abortion, Spontaneous↗
PubMed1992

Serum relaxin concentrations in patients with out-of-phase endometrial biopsies.

When luteal phase relaxin concentrations were summed to give an integrated measure (pg/mL per cycle), relaxin was found to be significantly lower in those cycles with an out-of-phase endometrial biopsy. In addition, peak relaxin concentrations were lower in out-of-phase cycles compared with normal cycles. These data indicate that relaxin secretion may be related to normal luteal function and suggest that shortening of the luteal phase results in reduced relaxin production. Measurement of circulating relaxin may prove to be useful in making the diagnosis of out-of-phase biopsy and needs to be assessed for its usefulness in diagnosing abnormal luteal function.

Biopsy↗
PubMed1992

Accuracy and precision of computer-aided sperm analysis in multicenter studies.

STUDY OBJECTIVES: To develop methods of instrument calibration and standardization that enable the use of computer-aided sperm analysis (CASA) technology in multicenter studies of sperm motility. SETTING: Clinical semen evaluation for the andrology laboratory and in vitro fertilization programs. PATIENTS: Semen specimens were selected from the videotape archives of the University of California at Davis Andrology Laboratory and used to produce a videotape reference standard for CASA instrument testing and calibration. Four identical CASA instruments, two each at two sites, were used to analyze the videotape. Machine accuracy was verified by manual analysis of the videotape. RESULTS: The coefficient of variation (CV) for repeated measures was between 1% and 8% for each variable on all CASA instruments. Mean values for CASA parameters varied as a function of the digitization threshold. A minimum CV was obtained at a particular threshold setting, suggesting an optimum for each machine. Because of high within-machine precision, slight differences in mean values between machines were statistically significant for some variables and some specimens; such differences are probably not biologically significant. CONCLUSION: Multicenter standardization of CASA instrumentation is possible, but threshold settings are one source of variation that must be controlled using CVs or another means of objective calibration. One method is to adjust the threshold of each instrument until the count obtained by CASA equals the count obtained by the manual method used to determine the dilution requirements for neat semen.

Computers↗
PubMed1991

Semen quality in varicocele patients is characterized by tapered sperm cells.

We used a retrospective case-control study design to compare sperm morphology in 50 varicocele patients and 50 patients with idiopathic infertility. Cases and controls were matched for the percentage of motile sperm and total sperm number per ejaculate. Varicocele patients had significantly more tapered sperm (36% +/- 3% versus 15% +/- 2%) and significantly fewer oval sperm (41% +/- 3% versus 47% +/- 2%). There was no significant difference between cases and controls in any other morphological type.

Case-Control Studies↗
PubMed1991

Movement characteristics of human epididymal sperm used for fertilization of human oocytes in vitro.

STUDY OBJECTIVE: To develop mathematical models using kinematic parameters from Computer-Aided Sperm Analysis (CASA) that predict the fertilization rate of sperm recovered from the caput epididymidis and to test the hypothesis that fertilization was enhanced by the presence of specific sperm subpopulations in the inseminate. SETTING: In vitro fertilization (IVF) program. PATIENTS: Thirteen patients with congenital absence of the vas deferens provided epididymal sperm for IVF as well as for CASA. RESULTS: The mathematical model that was most predictive of fertilization rates included kinematic parameters of the epididymal aspirate (percent motility), the inseminate used for IVF (curvilinear velocity [VCL]), and the change in sperm movement after in vitro processing by the mini-Percoll technique (difference in amplitude of lateral head displacement [ALH]). Multivariate cluster analysis revealed that inseminates that resulted in higher fertilization rates had subpopulations of sperm that were characterized by high VCL and high mean angular displacement, as well as a greater change in ALH after processing. CONCLUSION: In vitro fertilization with epididymal sperm was more likely to succeed when the sperm population that was initially aspirated had a higher proportion of motile cells and when these sperm were capable of capacitation in vitro as indicated by the appearance of sperm subpopulations with motility that resembled hyperactivation.

Diagnosis, Computer-Assisted↗
PubMed1991

The use of nonmetal electrodes in electroejaculation of restrained but unanesthetized macaques.

A successful technique for electroejaculation with nonmetallic electrodes cut from defibrillation pads is described. Twenty-six adult male cynomolgus and eleven adult male rhesus macaques were electroejaculated while immobilized with chair restraint. From 123 attempted electroejaculations in both species of macaques, 119 semen specimens were obtained. The volume, concentration, % motility, and % normal forms of cynomolgus and rhesus macaque semen are presented. The use of nonmetallic electrodes provides a high quality ejaculate while minimizing the risks of adverse affects on valuable populations of macaques.

Animals↗
PubMed1991

Paternally inherited effects of gamma radiation on mouse preimplantation development detected by the chimera assay.

It has previously been shown that type B spermatogonia in male mice treated with 0.05 Gy of X rays undergo an alteration expressed by progeny embryos as a cellular proliferation disadvantage in a chimera assay. We wished to obtain information on the assay's detection limit to ionizing radiation and on the radiosensitive target in male germ cells. Male mice were briefly irradiated with 137Cs gamma rays at nominal absorbed doses of 0.0, 0.0015, 0.005, 0.010, or 0.05 Gy and then mated for the next 8 weeks to untreated females. Four-cell embryos from treated males (experimental embryos) were paired with FITC-labeled embryos from untreated males (control embryos) to form aggregation chimeras. The chimeras were cultured for 30-40 h and examined under phase-contrast and UV illumination for the number of unlabeled cells (from the experimental embryo) and total chimera cell number, which were then expressed as "proliferation ratios" (No. unlabeled cells/total chimera cell No.). Significant decreases in proliferation ratios were observed at postirradiation weeks 4, 6, and 7 for the 0.01-Gy dose group and at weeks 5-6 for the 0.05-Gy dose group. In addition, significantly lower ratios were observed with early and mid four-cell embryos, but not with late four-cell embryos. These results suggest that mouse male germ cells express a radiosensitive target(s) whose detection limit by the assay lies at an absorbed dose between 0.005 and 0.010 Gy for brief gamma irradiation and whose effect on embryonic cell proliferation might decay by the second cleavage.

Animals↗
PubMed1991

Relationship of serum estradiol and progesterone concentrations to the excretion profiles of their major urinary metabolites as measured by enzyme immunoassay and radioimmunoassay.

Paired daily blood and urine samples were collected from 10 apparently healthy premenopausal women to compare the hormone profiles of estradiol (E2) and progesterone in serum with those of estrone conjugates (E1Conj) and pregnanediol-3-glucuronide (PdG) in urine. Serum hormones were measured by radioimmunoassay (RIA) kits, whereas the urinary steroid metabolites were assessed by both RIA and enzyme immunoassay (EIA). RIA and EIA values for urinary E1Conj and PdG were not different, and both methods produced urinary profiles that paralleled the profile of the parent steroid in serum. However, the simplicity, flexibility, and economy of EIA will make this method more widely applicable. Mean E1Conj values lagged behind concentrations of serum E2 by one day or less, whereas daily urinary PdG profiles lagged behind serum progesterone by one to two days. Mean urinary profiles of E1Conj were similar whether or not creatinine was used to adjust for urine volume; however, creatinine indexing was beneficial when urinary profiles in individual cycles were compared with changes of serum E2.

Adult↗
PubMed1990

Immunization of male but not female mice with the sperm-specific isozyme of lactate dehydrogenase (LDH-C4) impairs fertilization in vivo.

The goals of this study were to determine the site at which fertility is impaired in mice immunized with LDH-C4 and to determine whether immunization of both males and females would have a greater antifertility effect than immunization of one sex alone. Mice were immunized with LDH-C4 in two systemic doses in Freund's adjuvants and two gastric doses in bicarbonate buffer. The presence of anti-LDH-C4 antibodies in uterine fluid was confirmed. Male and female mice were assigned to four blocks in which either the males, the females, both, or neither were immunized. Oviducts were viewed directly 1 h after mating for the presence of sperm. No significant effect of immunization on sperm transport to the oviduct could be demonstrated. Fertilization was evaluated 4 h after mating. It was found that immunization of males, but not females, impaired fertilization (19.6% versus 50.8% of the oocytes penetrated in 17 and 19 females, respectively). Orchitis was found histologically in 43.8% of the immunized males and 10% of the control males.

Animals↗
PubMed1990

Relaxin in the peri-implantation period.

The time of appearance of relaxin in peripheral blood was determined in conceptive and non-conceptive cycles using a sensitive and specific double-antibody enzyme-linked immunoassay for human relaxin. For study of relaxin in early pregnancy, daily plasma samples were collected from women receiving artificial insemination of donor semen. The day of ovulation was determined by daily LH monitoring and ultrasound observation. In three conceptive cycles, relaxin was significantly elevated over baseline 9-10 days following the LH peak. Relaxin concentrations quickly rose over the next 15 days of observation to over 800 pg/ml. Relaxin was observed to increase 1 to 2 days prior to the first detectable increase in plasma hCG as measured by enzyme-linked immunosorbent assay. To compare the relaxin profile in conceptive cycles with normal luteal phase concentrations, relaxin was also measured in daily plasma samples collected from women contracepting with barrier methods, bilateral tubal ligation, or abstinence. A small but consistent rise in relaxin in the late luteal phase was observed in nine of eleven women, which began 6-9 days after the LH peak, averaged approximately 50 pg/ml, and was declining by the next menses. It is concluded that a small but measurable rise in plasma relaxin is associated with the normal luteal phase and that relaxin secretion is accelerated around the time that hCG is first detected in conceptive cycles. This acceleration of relaxin secretion which is associated with the onset of hCG may provide additional evidence for identification of transient early pregnancy.

Chorionic Gonadotropin↗
PubMed1990

Cryopreservation of spermatozoa from cynomolgus monkeys (Macaca fascicularis).

Three egg-yolk diluents, which have been used successfully in cryopreservation of human spermatozoa, were compared for their ability to protect macaque semen against cryodamage. TEST (Tes + Tris + egg yolk), TEST with 20% skim milk (TSM), and egg yolk-citrate (EYC), each with 3 or 5% glycerol were compared using 12 ejaculates from 6 male cynomolgus macaques. Computer-aided analysis of sperm motion was used to determine the percentage motility (%M), curvilinear velocity (VCL), and linearity (LIN) of spermatozoa after thawing. The supravital stain Hoechst 33258 and a fluoresceinated pea lectin were used to determine the % of viable spermatozoa with intact acrosomes. TSM and TEST were superior to EYC in terms of % M and of % viable, acrosome-intact spermatozoa. TSM and TEST produced equivalent VCL and LIN values, while EYC had clearly reduced VCL and LIN. There were no interactions between diluent and glycerol level. The 3% glycerol level gave superior results to 5% glycerol for %M. EYC, which is widely used for cryopreservation of human spermatozoa, was not suitable for cynomolgus monkey semen. Artificial insemination with semen cryopreserved in TSM resulted in a healthy, full-term infant.

Acrosome↗
PubMed1990

Intrauterine insemination with ultrasound guidance in the long-tailed macaque (Macaca fascicularis).

Techniques used for the artificial insemination of macaques have primarily involved instillation of the ejaculate into the vagina or cervical canal. Intrauterine insemination has been performed previously but only as a surgical procedure. The application of ultrasound-guided techniques for this purpose provides a method for efficiently inseminating macaques in a relatively noninvasive fashion. This report describes the successful transabdominal ultrasound-guided insemination of the long-tailed macaque and the potential application of this procedure to a variety of nonhuman primate species.

Animals↗
PubMed1990

Mechanisms of filtration of morphologically abnormal human sperm by cervical mucus.

It is well known that cervical mucus restricts penetration of morphologically abnormal human sperm, both in vitro and in vivo. However, the mechanisms of such restriction are not well understood. Using videomicrography to simultaneously analyze the motions and morphology of individual human sperm, we analyzed differential penetration of normal and abnormal sperm into fresh human cervical mucus. Abnormal sperm swam slower in mucus than the normal sperm, but their flagellar beat parameters were not commensurately different. Multivariate statistical analysis of the relationship between individual sperm velocity and flagellar beat parameters indicated that the heads of the abnormal sperm experienced greater resistance from the mucus than did normal heads. Differential mucus resistance, more than altered motile vigor, appears to be responsible for the restriction of abnormal sperm during migration through mucus.

Cervix Mucus↗
PubMed1989

Factors regulating mammalian sperm migration through the female reproductive tract and oocyte vestments.

Mechanisms of mammalian sperm migration through the female reproductive tract and ovum vestments are described. The perspective is biophysical as well as biochemical and morphological, and the focus is upon the role of sperm motility in these processes. Sperm forward progression is characterized as an interactive process between the the cell and its environment, and the mediation of flagellar bend propagation by the physical properties of its surroundings is described. These properties, together with flagellar beat kinematics, sperm morphology, and surface properties, determine the magnitude of the forces generated by sperm and their consequent rate of progression. Sperm interactions with the cervical mucus, the cumulus oophorus, and the zona pellucida are described. The poorly understood affinity of the sperm surface for the macromolecules of the mucus, cumulus, and zona is stressed, as is the viscoelastic structural mechanical resistance of these biopolymers to sperm motion. The kinematics and consequences of hyperactivated sperm motion are presented, with emphasis on objective characterization of such motion (as a biomarker), along with analysis of the mechanical advantage that such motion may confer on spermatozoa during egg-vestment interaction.

Animals↗