Search PubMed⌕ Search

Biomedical subjects

D Mortimer

Publications and source records attributed to D Mortimer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Annual patterns of human sperm production and semen quality.

Mean monthly values for ejaculate volume, sperm density, total sperm count, and percentages of progressively motile, viable, and morphologically normal spermatozoa were calculated from semen analyses performed on the husbands of all couples (excluding cases of azoospermia) referred to an Infertility Service during the years 1975-1979. No significant seasonal variations in any parameter were found. Comparison of the patterns of sperm production with other published studies indicates a tendency for increased sperm production during the late winter and early spring months.

Humans↗
PubMed1982

The development of a clinical test of sperm migration to the site or fertilization.

In those patients whose infertility is unexplained after routine investigations, it is likely that there are defects of gamete transport, fertilization, or implantation. This paper describes the development of a test of sperm migration to the site of fertilization. A method of laparoscopic sperm recovery from the peritoneal cavity and fimbrial rinsings following insemination at midcycle is described. In all, 47 patients were studied, and spermatozoa were recovered in 55%. There was no difference in the success rate following artificial insemination or coital insemination. Successful sperm recovery could not be attributed to better semen quality or better timing of the procedure in the menstrual cycle. The spontaneous pregnancy rate in the positive sperm recovery group was significantly higher than in the negative group. A comparison was made between the results of the postcoital test and the results of laparoscopic sperm recovery. There was a poor correlation between the two tests. It is suggested that laparoscopic sperm recovery is useful in the investigation of and the further management of that group of patients whose infertility is unexplained.

Cervix Mucus↗
PubMed1982

An analysis of sperm function in cases of unexplained infertility: conventional criteria, movement characteristics, and fertilizing capacity.

A detailed analysis of semen quality was carried out in 85 couples with unexplained infertility by the use of conventional criteria of semen analysis, time-exposure photomicrography, and the zona-free hamster egg penetration test. According to the latter, 34.1% of the male partners exhibited evidence of defective sperm function, although only 4% of these patients were devoid of any demonstrable fertilizing capacity. Of the conventional parameters of semen analysis examined, the most revealing was the morphologic character of the sperm, which was significantly poorer (P less than 0.001) in the group with unexplained infertility than in the normal fertile control group and also showed a significant relationship (P less than 0.001) with the presence of subnormal fertilizing capacity in the hamster egg assay. A majority of movement characteristics measured by time-exposure photomicrography were significantly depressed in the group with unexplained infertility, compared with the normal fertile control group. In addition, certain of the movement characteristics investigated were significantly related to the fertilizing capacity of the spermatozoa; and, in this respect, a progressive swimming speed (greater than 25 micrometers/sec), a straight swimming mode of progression, and a small amplitude of lateral head displacement (Ah) all appeared to be important qualities.

Animals↗
PubMed1982

Sperm function in patients with unexplained infertility.

Sperm function was studied in 27 patients with hitherto unexplained infertility. The ability of spermatozoa to reach the site of fertilization was assessed by laparoscopic sperm recovery from the peritoneal fluid and fimbrial rinsings and sperm fertilizing capacity with the zona-free hamster egg penetration in vitro test. The ability of spermatozoa to reach the site of fertilization correlated significantly with their fertilizing capacity in vitro, but was totally unrelated to any of the conventional criteria of semen quality, including the postcapacitation movement characteristics of the spermatozoa. Among patients with unexplained infertility, there are individuals with defects of sperm function which cannot be identified by conventional clinical techniques.

Female↗
PubMed1982

Sex ratio of births resulting from artificial insemination.

A survey of available data has shown that the sex ratio of births is significantly affected both by the practice of artificial insemination (AI) and by the cryostorage of semen. Comparison of the sex ratio of all infants born in England, Scotland and Wales between 1969 and 1978 (51.5% males) with that of British births after AI showed that the prevalence rate of male births after AI with either fresh or cryostored semen was lower than that for the general population: fresh semen (47.8%); cryostored semen (42.9%). When data from European countries and the US were combined, AI with fresh semen significantly increased the prevalence rate of male infants to 57.7%, whereas AI with cryostored semen significantly decreased the rate to 49.7%. The mechanism/s whereby the cryostorage of spermatozoa affects the secondary sex ratio remains to be determined.

Female↗
PubMed1982

Morphological selection of human spermatozoa in vivo and in vitro.

Light microscopic assessment of human spermatozoa in post-coital samples of cervical mucus revealed a significant improvement in the general sperm morphology between the semen and the cervix. Further analysis showed that the excluded spermatozoa were more likely to be those with midpiece or tail defects that impaired motility. Significant changes were also found when the morphology of spermatozoa recovered from the uterus and Fallopian tubes following AIH was compared with the semen used for insemination: in the semen, uterus and oviducts there were respectively 53, 77 and 71% spermatozoa with completely normal morphology, and 12, 3 and 0.6% spermatozoa with defects of the midpiece and/or tail (as assessed by surface replica electron microscopy). Selection of spermatozoa in vitro by allowing them to swim upwards through a nickel mesh also reduced the number of spermatozoa with abnormal morphology, particularly of the midpiece and tail. It is concluded that the apparent selection of morphologically normal spermatozoa is not a direct function of the female tract, but that the spermatozoa can effect their own selection because of their differential motility.

Cervix Mucus↗
PubMed1982

Sperm transport in the human female reproductive tract in relation to semen analysis characteristics and time of ovulation.

Laparoscopic sperm recovery from the pouch of Douglas and tubal fimbriae was performed in 64 infertile couples. Spermatozoa were recovered from 16/35 couples investigated after AIH, and from 13/29 couples post coitum. The method of insemination had no effect on the result, which was positive in 45.3% of all couples, although AIH did result in significantly larger numbers of peritoneal spermatozoa. The number of peritoneal spermatozoa did not show any direct correlation with the number inseminated, but there were reductions along the tract of 5.83 (+/- 1.4 s.d.) orders of magnitude for total sperm count, and 5.52 (+/- 1.21 s.d.) for the number of motile spermatozoa. Only sperm motility had a significant influence on the success of sperm transport; spermatozoa were recovered from patients with sperm densities as low as 3.0 and 3.5 x 10(6)/ml, but with 56 and 44% motile spermatozoa. No influence of cycle day within the range +/- 4 days of ovulation on sperm transport was found. In 45 couples, routine semen analyses were apparently completely normal, but the incidence of sperm recovery was still only 49% (22/45), suggesting that a failure of sperm transport may have been a significant causative factor in their infertility.

Female↗
PubMed1982

Ultrastructural study of regressed and reactivated testes from Soay rams.

Testes from 4 sexually active and 4 sexually regressed adult Soay rams housed under artificial lighting were examined. The reduction in testis weight during sexual regression (reduced to 35% of active) was due to a decrease in the diameter of the seminiferous tubules with extensive involution of the basement membrane, a marked reduction in the number of germ cells maturing beyond the spermatocyte stages, and a general disorganization of all but the most basal region of the seminiferous epithelium. The Sertoli cells contained large lipid droplets and deposits of lipochrome pigment and large necrotic bodies. The Leydig cells showed some reduction in content of smooth endoplasmic reticulum during sexual regression although they were approximately 30 times less active steroidogenically as judged by the peripheral levels of testosterone. Blood levels of LH and FSH were significantly reduced compared to those in sexually active animals, while the prolactin levels were much increased.

Animals↗
PubMed1982

Semen analysis parameters and their interrelationships in suspected infertile men.

The mean semen parameters and their interrelationships are reported for the first semen analyses performed on a population of 1801 suspected infertile men. For this population, the mean (+/- SD) sperm density was 84.3 (+/- 78.3) x 10(6)/ml, the mean volume was 3.3 (+/- 1.7) ml, and the mean total sperm count was 265.6 (+/- 270.0) x 10(6)/ejaculate. After exclusion of 90 cases of azoospermia (5.0% of the patients), these values became 88.7 (+/- 77.8), 3.4 (+/- 1.7), and 279.5 (+/- 269.9), respectively. For the population of patients with spermatozoa in their semen, the mean (+/- SD;n) percentages of motile, viable and morphological normal spermatozoa were 50.3 (+/- 15.4; 1677), 77.3 (+/- 11.9; 830), and 54.2 (+/- 11.7; 1587), respectively. Loge transformation of the sperm density values in sperm-positive ejaculates gave a mean of 51.9 x 10(6)/ml with 95% confidence limits of 12.3 to 219.0 x 10(6)/ml. Ejaculate volume was slightly, but significantly, reduced in cases of azoospermia and polyzoospermia (i.e., greater than 200 x 10(6)/ml). Significant positive correlations were found between sperm density and the parameters of sperm quality, and also between these latter three parameters themselves. Increasing semen viscosity had no effect upon the morphology of the spermatozoa, but in ejaculates with marked or high viscosity the motility and viability of the spermatozoa were significantly depressed.

Humans↗
PubMed1982

Influence of abstinence and ejaculation-to-analysis delay on semen analysis parameters of suspected infertile men.

No significant differences were found between mean values calculated for daily increases in abstinence for any semen analysis parameter, with the exception of ejaculate volume between 1 and 2 days of abstinence. However, graphical analysis revealed significant trend lines for both ejaculate volume and total sperm count. The mean ejaculate volume increased by 1.0 ml between the first and second days of abstinence, and at approximately 0.3 ml/day thereafter until the 5th day. The total sperm count showed a mean daily increase of 50-60 x 10(6) spermatozoa/day. Quantitative differences exist in the evolution of these two parameters in comparison to normal fertile men. There were decreased mean percentages of motile and viable spermatozoa at short periods (less than or equal to 1 day) of abstinence, increasing up until the 2nd (% viable) or 3rd (% motile) days of abstinence, with decreased values at greater than 5 days. The mean percentage of morphologically normal spermatozoa was unaffected by the duration of abstinence. Delays of up to 3 hr between ejaculation and analysis did not seriously affect the mean semen parameters.

Ejaculation↗
PubMed1981

Glutamic-oxalacetic transaminase leakage from human spermatozoa as an indicator of cryodamage.

The levels of extracellular glutamic-oxalacetic transaminase (GOT: EC 2.6.1.1) activity have been measured in cell-free supernatants of human semen and of semen + cryoprotectant mixtures both before freezing by either cryostorage or quench-freezing regimes, and after subsequent thawing. The mean level of GOT activity in seminal plasma was 293 (+/- 15 sem) IU/l at 37 degrees C, this being 15 times the level in normal blood plasma. Seminal GOT is positively correlated (p less than 0.001) with the sperm density. Increases in the extracellular GOT activity were measured after both cryostorage and quench-freezing, but the latter procedure, which destroys all sperm motility, caused an average of 2.8 times more enzyme release than cryostorage. Although the release of GOT from human spermatozoa during freezing and thawing does not correlate with the commonly used percent return of motility as an estimate of cryosurvival, possible explantations for this finding, and its importance, are discussed. Objective measurements such as GOT release may be developed to augment, if not replace, subjective estimations of sperm motility as indicators of cellular integrity in studies of sperm cryostorage.

Aspartate Aminotransferases↗
PubMed1980

Laparoscopic sperm recovery in infertile women.

Sperm recovery from the peritoneal fluid was attempted in a group of infertile women in whom it was anticipated that all routine investigations would be normal (commonly referred to as 'normal infertiles'). Forty-four couples were recruited into the study but in retrospect only 24 met the study criteria of normal semen, normal pelvis and appropriate timing. In 15 of these 24 patients, spermatozoa were covered from the peritoneal fluid, and so far seven have become pregnant. In the nine patients where spermatozoa were not recovered, none have so far become pregnant. There was no correlation between sperm recovery and the quality of the post-insemination cervical mucus examination. This test allows more accurate assessment of the ability of spermatozoa to reach the site of fertilization.

Ascitic Fluid↗
PubMed1979

Functional anatomy of haploid and diploid rabbit spermatozoa.

Ultrastructural studies of surface replicas of haploid and diploid rabbit spermatozoa after treatment with various chemical media have shown that the various structural components of the diploid sperm head possess the same stabilities and labilities as those of the haploid. Therefore, at least in terms of functional anatomy, diploid rabbit spermatozoa should be capable of penetrating the egg investments and undergoing syngamy.

Acrosome↗
PubMed1979

Differential motility of diploid rabbit spermatozoa.

When rabbit spermatozoa were suspended in a fluid column and incubated for a period of 2.5 hr, there was a change in the relative distribution of morphologically normal, abnormal, and dead spermatozoa. Live, morphologically normal spermatozoa were concentrated in the lower levels of the column, whereas dead and most morphologically abnormal spermatozoa were distributed throughout the upper levels. It appears that the motility of various types of morphologically abnormal rabbit spermatozoa is impaired. These observations strengthen the proposal that the cervix plays an essentially passive role in the selection of spermatozoa during sperm transport in mammals with vaginal insemination.

Animals↗
PubMed1977

The survival and transport to the site of fertilization of diploid rabbit spermatozoa.

The possible involvement of diploid spermatozoa in the production of triploid zygotes in the rabbit has been investigated in terms of the success of diploids relative to haploids in reaching the site of fertilization, with special reference to any possible selectivity of sperm transport within the female tract. The observed large significant reduction in the incidence of diploid spermatozoa between the ejaculate and the oviducts would greatly reduce the chances of, but not necessarily prevent, a diploid spermatozoon fertilizing an egg. This reduction appears to be due to a combination of the reduced survival of diploids in the female tract and a selectivity of sperm transport dependent on sperm motility.

Animals↗
PubMed1976

Nuclear pores in the spermatozoon of the rat.

The paper describes a hexagonal array of nuclear pores in a non-redundant region of the nuclear envelope underlying the basal surface of the rat spermatozoon head. It is concluded that intranuclear material protruding through these pores is the cause of the characteristic rows of circular 'bumps' found in surface replicas of this region.

Animals↗
PubMedDate not supplied

Human sperm morphology and the outcome of modified Kremer tests.

The outcome of homologous in vitro tests of human sperm penetration into cervical mucus in couples undergoing infertility investigations have been shown to be correlated with the proportion of morphologically normal spermatozoa in the semen samples used for the tests. In addition, the ejaculates producing poor tests contained significantly more spermatozoa with defective tails than those semen samples producing normal or, surprisingly, negative tests.

Cervix Mucus↗