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Biomedical subjects

J M Cummins

Publications and source records attributed to J M Cummins.

At least 73 records · Page 4Linked to original sources
PubMed1988

The acrosome reaction in spermatozoa of the grey-headed flying fox (Pteropus poliocephalus: Chiroptera) exposes barbed subacrosomal material.

Acrosome reactions were induced in seminal spermatozoa of the megachiropteran Pteropus poliocephalus, the grey-headed flying fox, using the ionophore A23187 (10 microM in Tyrodes solution with 1% w/v BSA). Samples were taken at 0, 10, and 120 minutes and fixed for electron microscopy. Initial motility of approximately 70% decreased to approximately 10% over 2 hours. The first motile spermatozoa without acrosomal caps were seen after 6 minutes, and by 90 minutes approximately 60% of motile spermatozoa had completed the acrosome reaction. The first sign of the reaction (by TEM) appears to be swelling and cavitation of the acrosomal matrix within the apical and principal segments, followed or possibly accompanied by fusion and fenestration of the outer acrosomal and plasma membranes and dispersion of the matrix except from the equatorial segment. The end-product of the reaction thus conforms to that seen in other eutherian mammals. However, the reaction exposes a uniquely moulded organization of subacrosomal material ("pseudoperforatorium"), shaped like an anvil over the rostral rim of the flattened nucleus and encased by the remaining inner acrosomal membrane. This has two "lateral" spikes on each side that extend approximately to the same width as the head in the region of the equatorial segment. While these barbs could serve to stabilize or anchor the apical segment of the acrosome, their exposure following the acrosome reaction suggests some specific mechanical role in penetration of the zona pellucida or in protecting more caudal structures from abrasive damage.

Acrosome↗
PubMed1988

The effect of cryopreservation on functional correlates of embryo integrity.

To assess possible functional effects of the procedures involved in freezing/thawing of mammalian embryos, uptake of 3H-glycine and 125I-BSA (bovine serum albumin) was measured in mouse two-cell embryos and morulae before and after freezing. None of the procedures of dehydration, rehydration, or freezing affected glycine uptake significantly. Earlier results for uptake of 125I-BSA by fresh embryos which indicated an increase in endocytic activity between morula and blastocyst stages were confirmed, and hydrolysis of endocytosed 125I-BSA by morulae but not two-cell embryos was observed. Only 53 +/- 9% of two-cell embryos but 83 +/- 7% of morulae were apparently normal after freezing and thawing. Apparently normal frozen/thawed two-cell embryos were twice as active in 125I-BSA uptake as controls. This was not the case for morulae. The results suggest that freezing/thawing effects endocytotic processes in two-cell embryos but not morulae.

Animals↗
PubMed1988

The effects of human interferon-alpha upon in vitro canine immune responses.

The effects of varying amounts (100.0-0.01 units/ml) of human interferon (IFN) alpha upon in vitro canine immune responses were studied. Exogenous heterologous species IFN-alpha suppressed B-cell differentiation in a dose-dependent fashion and enhanced interleukin-2 production (P less than 0.05) by activated T-lymphocytes. Interferon enhanced natural killer (NK) cytotoxicity when tested against NK-resistant target cells (less than 0.05). One hundred units IFN/ml increased interleukin-1 production by canine monocytes, but this effect was not statistically significant. Exogenous IFN had no discernible effect upon lectin-induced lymphocyte blastogenesis. The results of this study demonstrate that human IFN-alpha does affect various canine lymphocyte functions and these effects depend upon the in vitro assay system employed.

Adjuvants, Immunologic↗
PubMed1988

Preliminary results using pentoxifylline in a pronuclear stage tubal transfer (PROST) program for severe male factor infertility.

In vitro trials with washed spermatozoa incubated in medium containing 1 mg/ml of the methyl xanthine phosphodiesterase inhibitor PF showed improved counts of total motile and total progressively motile spermatozoa in cases of oligospermia/asthenospermia. Application of this agent in a PROST program for a series of nine couples presenting for treatment with histories of failed fertilization in vitro resulted in five pregnancies (four singleton, one triplet) and the subsequent delivery of normal infants. The results warrant further evaluation of this sperm treatment for cases of severe male factor infertility.

Embryo Transfer↗
PubMed1988

Fertilization of human oocytes in relation to varying delay before insemination.

Fertilization and pregnancy rates in an in vitro fertilization and embryo transfer program were studied after a range of insemination times of between 1 and 26 hours after oocyte recovery. There was no significant variation in fertilization rate across this range. The pregnancy rate showed no significant variation for insemination between 3 and 16 hours after aspiration. However, it was disappointing at 2 hours (3%), and no pregnancies were achieved from the nine patients whose ova were inseminated 20 or more hours after aspiration. It is concluded that mature oocytes can be inseminated in vitro at any time between 3 and 16 hours after aspiration and still retain the same potential to produce a pregnancy.

Female↗
PubMed1988

Isolation of a chemotactic protein for neutrophils from human ovarian follicular fluid.

Human follicular fluid was found to contain a factor chemotactic for human neutrophils. This chemotactic activity was shown to be heat labile and trypsin sensitive. Gel permeation chromatography experiments indicate that the chemotactic protein has an approximate molecular weight of 100 kd. Isoelectric focussing suggests an isoelectric point for this protein of around 5.8. The biologic and clinical significance of this apparently unique chemotactic protein remains to be determined.

Body Fluids↗
PubMed1988

Nitrogen kinetics of infectious bovine rhinotracheitis-stressed calves.

Eight crossbred feeder steers were used in two consecutive N balance studies to investigate the effects of infectious bovine rhinotracheitis virus (IBRV) on N kinetics. Balance Study 1, which followed a 10-d acclimation phase, consisted of 7 d of sample collection referred to as the healthy phase (d -7 to d -1). Study 2, the IBRV-infected phase, began 2 d after a nasal IBRV challenge and continued for 6 d (d 2 to d 8). A stable isotope, [15N]-glycine, was used to determine N kinetics in both studies. Steers weighed 203 kg at the beginning of the study, 208 kg at IBRV infection and 194 kg at the end of study. Infection with IBRV increased (P less than .05) urinary N excretion from 17.9 to 31.5 g/d. Daily N balance was reduced (P less than .05) during infection from 21.2 to -3.3 g/d. Total serum proteins increased (P less than .05) during infection from 6.6 to 7.1 g/100 ml, the increase being predominantly in the alpha and gamma globulin fractions. Blood urea-N increased (P less than .05) during infection from 6.5 to 12.9 mg/100 ml. The urine excretion curve of the stable isotope and the N balance data indicated that IBRV infection increased N turnover and altered tissue utilization of N.

Animals↗
PubMed1988

Oral use of human alpha interferon in cats.

Low doses (0.5 or 5.0 U) of human alpha interferon (HuIFN alpha) given orally prevented the experimental development of fatal feline leukemia virus (FeLV)-related disease. Twenty-one FeLV-susceptible cats were inoculated with the Rickard strain of FeLV. Cats given oral HuIFN alpha survived significantly (p less than 0.001) longer than untreated FeLV-infected cats. Moreover, only 4 of 13 (30.8%) HuIFN alpha-treated cats developed clinical disease during the course of the study, whereas 100% of the untreated control cats developed fatal FeLV-related disease. Thus, in experimental retroviral disease, heterologous species HuIFN alpha provided significant clinical benefits.

Administration, Oral↗
PubMed1987

Results using medium supplemented with either fresh or frozen stored serum in human in vitro fertilization.

This study retrospectively compared the success of in vitro fertilization (IVF) among patients whose gametes had been incubated either in medium supplemented with freshly prepared pooled serum (331 cases) or in pooled serum which had been stored at -20 degrees C prior to use (728 cases). Frozen stored serum was as effective as fresh serum with regard to the proportion of oocytes which fertilized and embryos which implanted and was not associated with any increased incidence of fetal loss during postimplantation development.

Blood Physiological Phenomena↗
PubMed1986

A live Pasteurella haemolytica vaccine efficacy trial.

A live Pasteurella haemolytica serotype 1 vaccine was used in an efficacy trial conducted on 100 lightweight feeder calves purchased from a Florida ranch. Forty-one calves were inoculated with the vaccine intradermally in the neck. Fifty-nine calves served as nonvaccinated controls. Fourteen days later, the calves were shipped to an order buyer in eastern Tennessee, where the calves were mixed with 60 local calves in a community sale barn for 72 hours. After 3 additional days, the calves were shipped to a research feedlot in Bushland, Tex. They remained in the feedlot for 56 days, and the test was concluded 76 days after vaccination. The P haemolytica vaccine had no significant effect on performance, morbidity, or mortality. There was no significant difference between the vaccinated and nonvaccinated calves in the number of times Pasteurella was isolated. The calves became seropositive to bovine viral diarrhea virus, respiratory syncytial virus, and infectious bovine rhinotracheitis (IBR) virus during the 76-day experiment. All calves initially were seropositive to parainfluenza-3 virus. A virulent outbreak of IBR occurred 30 days after the calves arrived at the feedlot. Before the onset of IBR, the isolation of P haemolytica serotype 1 from nasal turbinates was rare (2 of 500 nasal swabs). After the IBR outbreak, P haemolytica serotype 1 was isolated from 40 of 92 calves.

Animals↗
PubMed1986

Reproduction in the male honey possum (Tarsipes rostratus: Marsupialia): the epididymis.

The epididymis of the adult honey possum, Tarsipes rostratus, is enclosed by a heavily pigmented tunica vaginalis and lies with the testis in a prominent prepenile scrotum. It is connected to the testis by a single ductus efferentis and is lined by approximately equal numbers of cuboidal ciliated and principal cells. It is unusual for marsupials in having no well-defined compartments or fibrous septae and in having extensive convolutions of the duct only at the caudal flexure. Three principal functional zones (initial, middle, and terminal segments) were identified in the epididymis, based on epithelial type and ultrastructural evidence of sperm maturation. Luminal diameter increases progressively throughout the tract, and epithelial height variations (from about 2 to 20 microns) are greatest in the terminal segment. The epithelium itself is remarkably low (maximum of 21.6 microns) compared with that seen in the epididymis of other mammals. The thickness of the peritubular smooth muscle coat increases close to the junction of the epididymis and ductus deferens. Sperm concentrations were estimated from counts of sperm nuclei and thus can be no more than approximations. The figures are consistent, however, with a rapid increase in concentration in the initial segment, indicating extensive fluid resorption. Sperm concentrations appear to peak in the distal zone of the terminal segment, although sampling problems and wide variations in count make such a conclusion only tentative. Principal and basal cells are the predominant cell types in the epididymal epithelium. Basal cells are most abundant in the initial and distal middle segment. Principal cells show structural evidence of active exchange with the luminal contents and have abundant apical stereocilia, the structure of which depends on the epididymal zone. Other cell types occur less commonly in the epithelium. Lipid-rich and phagocytic principal cells are restricted to the middle and distal zones of the middle segment, respectively. Clear cells, restricted to the terminal segment, and halo cells were found in very low numbers. As in some other marsupials, principal cells (possibly specialized for this function) selectively remove cytoplasmic droplets and probably other cellular debris from the luminal contents. In Tarsipes, however, this process is not very efficient, and many discarded droplets pass through to the terminal segment where they form large masses of debris associated with aggregates of degenerating spermatozoa.

Animals↗
PubMed1986

Labelling of living mammalian spermatozoa with the fluorescent thiol alkylating agent, monobromobimane (MB): immobilization upon exposure to ultraviolet light and analysis of acrosomal status.

Living spermatozoa of seven mammalian species were treated with the thiol-alkylating fluorescent labelling compound, monobromobimane (MBBR). MB-labelling alone had no effect on sperm motility, nor on the time course or ability of golden hamster spermatozoa to undergo the acrosome reaction when capacitated in vitro. Exposure of MB-labelled spermatozoa to ultraviolet (UV) light and excitation of the MB fluorochrome resulted in virtually immediate immobilization of the spermatozoa without affecting acrosomal status. UV exposure of unlabelled spermatozoa for up to 30 sec had no effect upon motility. Immobilization of MB-labelled spermatozoa depended on the midpiece being irradiated, as irradiation of the head alone, or of the more distal parts of the principal piece, had little or no effect upon motility. Labelling with MB followed by immobilization of individually selected spermatozoa was most useful for detailing the course and site of occurrence of the acrosome reaction during penetration of the cumulus oophorus by golden hamster spermatozoa in vitro. In these often hyperactivated spermatozoa, precise determination of the acrosomal status could not often otherwise be made due to the difficulty in visualizing the acrosomal region of a vigorously thrashing, hyperactivated spermatozoon. This technique should prove valuable in a variety of studies on sperm motility, capacitation and fertilization, and could also be extended to other cell systems.

Acrosome↗
PubMed1986

Normal development of hamster and rabbit eggs fertilized by spermatozoa labelled with the fluorescent thiol alkylating agent, monobromobimane.

Cauda epididymal spermatozoa of the golden hamster were labelled with the thiol-alkylating reagent, monobromobimane (MB). Female hamsters underwent uterine insemination with labelled spermatozoa at laparotomy under metofane anesthesia. All 12 females examined between 5 and 54 h postinsemination yielded a total of 83/100 (83%) eggs in the process of fertilization or embryos. Under ultraviolet (UV) exposure all exhibited a fluorescent tail which, in the 4- and 8-cell embryos, could be seen to be fraying or disintegrating. As cleavage progressed, labelled tail components came to be restricted among the blastomeres such that at the 4- and 8-cell stage the tail could be seen in only one to three blastomeres. To study complete development and pregnancy another 12 females received uterine insemination. After recovery from anesthesia (approximately equal to 4 h) these females were mated with a vasectomized male bearing a dominant genetic marker (black eyes) to allow unequivocal determination of paternity in the fetuses and young produced. Seven became pregnant with one female losing her pregnancy about Day 7 of gestation. Two females sacrificed on Day 13 produced 17 normal fetuses and one resorption. Four females delivered 16 young, all normal at birth and in subsequent growth and fertility. In addition, insemination of female rabbits with MB-labelled spermatozoa yielded normal embryos (50/52 96%) from 3 does on Day 2 and (38/64 60%) from 4 does on Days 4 or 5. Two normal litters (9 bunnies) have delivered from 3 does allowed to carry to term.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

A formula for scoring human embryo growth rates in in vitro fertilization: its value in predicting pregnancy and in comparison with visual estimates of embryo quality.

Two systems for measuring embryo development in vitro were evaluated. One was a 1-4 scale based on a subjective evaluation of embryo quality (EQ) from microscopic appearance. In addition, a formula for scoring embryo growth rate in vitro was developed. The embryo development rating (EDR) was based on the ratio between the time at which embryos were observed at a particular stage after insemination and the time at which they would be expected to reach that stage in a hypothetical "ideal" growth rate with a cell cycle length of 11.9 hr. Using this scoring system, "normally" growing embryos scored 100. This approach was aimed at partially normalizing the data and allowed all embryos to be analyzed similarly regardless of the time of observation. Analysis of 1539 embryo replacements resulting in 232 clinical pregnancies showed that both EDR and embryo-quality scores were of value in predicting success, with clinical pregnancy most likely to eventuate from a combination of moderate to good EQ scores (2-4) coupled with average or above-average growth rates (EDR scores from 90 to 129). Poor-quality and very slowly or very rapidly growing embryos were underrepresented in cycles that proceeded to pregnancy. These inferences were based on all embryos transferred (mean, 2.73 per transfer cycle), and they were substantiated by an analysis of 33 pregnancies resulting from replacement of a single embryo and from 18 pregnancies in which all embryos scored the same with both systems. EQ and EDR were significantly associated with each other and together provide a valuable guide in predicting pregnancy, in selecting embryos for freezing, and in monitoring day-to-day performance in the in vitro fertilization (IVF) program.

Embryo Transfer↗