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Biomedical subjects

C L Barratt

Publications and source records attributed to C L Barratt.

108 records · Page 6Linked to original sources
PubMed1986

Fate of superfluous sperm products after vasectomy and in the normal male tract of the mouse.

The progression of 3H-labelled spermatozoa (thymidine or arginine) was followed through the tracts of unilaterally vasectomized, bilaterally vasectomized, oligozoospermic (t6/tw5) and normal mice; the regional lymph nodes were also investigated. The same rate of sperm production and transport was found in normal and in vasectomized tracts, down to the corpus epididymidis; there was some delay in spermatozoa entering the cauda in the vasectomized tracts. In the mouse, therefore, vasectomy does not affect the rates of sperm production or transport until just before the blockage in the swollen cauda epididymidis. Radioactivity appeared in the caudal and 'para-aortic' lymph nodes as the radioactive spermatozoa passed from the corpus, showing that this is one route of disposal of spermatozoa, or of sperm products, after vasectomy. Naturally oligozoospermic and normal mice gave similar results; again the caudal, iliac and renal lymph nodes received radioactive spermatozoa/sperm products. Some loss of (by definition) superfluous spermatozoa in the normal male tract therefore occurs naturally by this route, and we suggest that vasectomy further exploits this physiological pathway. This would account for the finding that many males do not make antisperm antibodies after vasectomy, just as normal males do not, even though their lymph nodes normally receive spermatozoa/sperm products.

Animals↗
PubMedDate not supplied

Quality control during the conventional analysis of semen, an essential exercise.

Intra- and inter-technician variability in assessing sperm motility by the methods recently advocated by the World Health Organization (WHO) were studied. The intra- and inter-technician variability in estimating sperm concentration and the intra-technician variability in assessing sperm morphology were also examined. Intra-technician variability in assessing sperm motility appeared to be related to the natural ability and/or training of the observer. Although in general the intra-technician variability was low, there were marked and clinically significant differences between observers when assessing the same semen sample. There was no significant difference between observers in the assessment of sperm concentration, and intra-technician variability was low. When assessing sperm morphology, the intra-technician variability was potentially large (above a level of 20% morphologically ideal spermatozoa). Technicians should be recruited who have natural ability as observers. Quality control appears to be an essential exercise for any center that plans to relate semen parameters to fertility outcome.

Evaluation Studies as Topic↗
PubMedDate not supplied

The potential shortcomings of measuring hyperactivated motility by computer-aided sperm analysis when sperm motion is multiphasic.

This paper was written from the standpoint that computer-aided sperm analysis (CASA) instruments, which capture a 'snapshot' of sperm trajectories in order to generate their data, may provide a poor measure of hyperactivated motility in a sperm population where hyperactivation is multiphasic in nature. To illustrate this point, a series of theoretical sperm populations were constructed which varied subtly but significantly in the nature of the hyperactivated behaviour expressed by spermatozoa. The parameters which were manipulated were: (i) the number of hyperactivated phases exhibited within a given period of time; (ii) the duration of these phases; and (iii) proportion of spermatozoa within the population which exhibited hyperactivated phases. These populations were then subject to an analysis in which snapshots of sperm motion were examined to determine the percentage of hyperactivated spermatozoa for that population. The results indicated that whilst this snapshot approach to quantifying hyperactivation could provide a figure for the percentage of hyperactivated spermatozoa within the sample window, this often inaccurately described the underlying behaviour of the population. Since there is very likely to be a significant amount of biological information contained within the nature of multiphasic behaviour, this paper has argued that this aspect of snapshot analysis is one which requires serious consideration by CASA manufacturers and medical researchers.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Semen characteristics of 49 fertile males.

We examined the semen characteristics of 49 men whose partners had conceived within the last 16 weeks. There was considerable variation in the semen results. The % of morphologically ideal forms and the absence of sperm bound antibodies appeared to be the two most important semen characteristics when assessing the fertilising potential of the samples. A large proportion of samples (70%) when compared to the WHO standards of normality, were classed abnormal, however, only 25% of the samples had greater than 2 abnormal characteristics. It is diagnostically more relevant to determine the number of abnormalities within a sample rather than categorising the sample as "normal" or "abnormal".

Adult↗
PubMedDate not supplied

Postcoital test: which form of spermatozoal motility is associated with a good fertility outcome?

The objectives of this study were to examine the predictive value of the PCT in relation to treatment-independent conception rates, to determine which cutoff point best predicted fertility outcome, and which form of spermatozoal motility on PCT is most significantly related to fertility outcome. A prospective study was undertaken of couples referred for the investigation of "unexplained" infertility. One hundred and twenty six couples were recruited between July 1984 and April 1986. On further investigation female infertility factors were identified in 32 (25%) of couples, who were therefore excluded from the study. All conceptions were treatment independent. The relationship between the result of the postcoital test and the chance of conception was studied using a modification of Cox's regression model of life table analysis. The mean length of involuntary infertility prior to referral was 75 months (range = 18-192, SD = 39.2). The mean length of follow-up was 18 months (range = 1-34, SD = 8.4). A 98% follow-up rate was achieved. Eighteen women conceived, giving a 32-month treatment-independent conception rate of 22%. A cutoff point of one spermatozoon exhibiting sluggish motility per HPF was the most effective method of classifying the results of the postcoital test (X2(1) = 4.28, P = 0.037, RR = 4.7. This would suggest that the most efficient form of spermatozoal motion in cervical mucus is slow or sluggish motility.

Adult↗
PubMedDate not supplied

The importance of employing stringent methods to recruit fertile male controls.

Two methods of recruiting fertile male controls were evaluated and compared. The first group was recruited from the partners of women attending an antenatal clinic without obtaining details of their reproductive history. The second group was recruited after obtaining a detailed reproductive history from the couple and employing stringent entry criteria. Entry criteria for the second group included a length of exposure to the risk of pregnancy of not more than 12 months and no previous episode of involuntary infertility for either partner. There were significant differences between the distributions of semen parameters obtained from the two groups, indicating that the selection criteria for "fertile" men significantly influence results obtained and therefore that it is important to employ stringent criteria for the recruitment of fertile male controls. The group which was recruited by stringent criteria (mean length of exposure to the risk of pregnancy of 3 months) was characterised by a significantly higher median concentration of spermatozoa which exhibited slow linear or nonlinear motility. This confirms the findings of a previous study which suggested that slow linear or nonlinear motility are superior forms of spermatozoal motion.

Adult↗
PubMedDate not supplied

Male alcohol consumption and fecundity in couples attending an infertility clinic.

The relationship between male alcohol intake and fertility was studied for 258 couples attending an infertility clinic. 21% consumed less than 1 unit per week on average, 10% consumed between 1 and 5 units per week, 23% consumed between 6 and 10 units per week, 27% consumed 11 to 20 units per week and 19% consumed more than 20 units per week. There was no significant association between alcohol consumption and any semen parameter. 110 men had a female partner who was apparently normal. There was no significant difference in the alcohol intake between the 'normal' and 'abnormal' female groups. Couples were followed-up for up to 32 months. Sixteen women had a treatment independent conception within the 'normal' female group. There was no significant association between the amount of alcohol consumed per week and the fertility outcome.

Adult↗
PubMedDate not supplied

Male cigarette smoking and fecundity in couples attending an infertility clinic.

The relationship between male cigarette smoking and fertility was studied for 330 couples attending an infertility clinic. 59% did not smoke, 10% smoked between 1 and 5 per day, 8% smoked between 6 and 10 per day, 16% smoked 11-20 per day and 7% smoked more than 20 per day. There was no significant association between smoking and any semen parameter. 138 men had a female partner who was apparently normal. There was no significant difference in smoking habits between the 'normal' and 'abnormal' female groups. Couples were followed-up for up to 32 months. Nineteen women had a treatment independent conception within the 'normal' female group. There was no significant association between the number of cigarettes smoked and the fertility outcome.

Adult↗
PubMedDate not supplied

Preliminary communication: possible role of reactive nitrogen intermediates in leucocyte-mediated sperm dysfunction.

This preliminary study was designed to examine whether nitric oxide, a reactive nitrogen intermediate produced by leukocyte metabolism of L-arginine, could reduce sperm motility. Increasing doses (10(-6)-10(-4) M) of the nitric oxide-generating drug, sodium nitroprusside (SNP) were added to motile sperm preparations and incubated over 20 hr. Quantitative sperm motility measurements were made using a computer-assisted motility analyzer in each treated sample and controls over this time period. The percentage of motile sperm, progressive motility, and concentration of motile cells were all significantly reduced with all doses of SNP. This effect was not observed in preparations treated with oxyhaemoglobin (HbO2). Mean path velocity was unaltered. Sperm viability in SNP treated sperm did not differ significantly from that of control sperm over the same time period. We conclude that further experiments are required to determine whether the production of nitric oxide/reactive nitrogen intermediates in vivo by activated leukocytes could be a contributory factor in the development of immunologic infertility.

Dose-Response Relationship, Drug↗
PubMedDate not supplied

The effects of lead on the male rat reproductive system.

Lead acetate was administered to male rats for 9 weeks in doses of 0.3, 33 or 300 mg/kg daily by gavage. The lowest dose significantly reduced the number of sperm in the cauda epididymis and the highest dose increased the proportion of abnormal sperm in the cauda. There was no significant effect on the number of each type of testicular germ cell. The highest dose of lead reduced the rate of incorporation of lysine into protein significantly in the liver but not in the testes. The highest dose also reduced body weight gain significantly. The surprisingly slight effect of lead on the germinal tissue may be due to a protective effect of the blood-testes barrier.

Animals↗
PubMedDate not supplied

The characterisation of non-sperm cells in the ejaculates of fertile men using transmission electron microscopy.

The non-spermatozoal cells (NSC) in the semen samples of 20 fertile human males have been studied by transmission electron microscopy (TEM), in order to accurately distinguish between the different types of cell present and to give a quantitative profile of their relative proportions. The main seminal constituents of the average fertile man were found to be the germinal elements, accounting for 84.0% of the total NSC population. Of this percentage the anucleate bodies, designated "CM" in this study, were the greatest component (43.0%, SEM +/- 4.7). Spermatids were the next commonly occurring cell (22.2%, SEM +/- 2.9), the anucleate cellular masses with organelles, CM(O)'s and the spermatocytes making up the remaining 18.8%. Leucocytes accounted for 13% of the total NSC, respectively: neutrophils - 12% (SEM +/- 4.5); macrophages - 0.9% (SEM +/- 0.3) lymphocytes - 0.1% (SEM +/- 0.1). The remaining 3% consisted of 2.3% (SEM +/- 0.7) epithelial cells and 0.7% (SEM +/- 0.4) Sertoli cells. The principal conclusions reached were: that some normal ejaculates host active phagocytosis and possibly macrophage activation; that anucleate bodies which form a major component of the ejaculate merit further quantitative study and that the shedding of spermatids is an interesting and important aspect of ejaculation.

Cytoplasm↗
PubMedDate not supplied

Ultrastructural morphometric data of human spermatozoa.

A morphometric study of the volumetric parameters of human spermatozoa has been carried out, volume densities being obtained by point counting and converted to absolute volumes by employing the point-sampled intercept method. Data for the Spermatozoa from the semen of 15 recently fertile men are presented. The significance of the results is discussed in relation to results obtained by other methods and in relation to the building of a diagnostic reference database.

Humans↗
PubMedDate not supplied

The acrosome reaction-inducing effect of human follicular and oviductal fluid.

The human sperm acrosome reaction (AR) can be induced in vitro by a variety of naturally occurring and synthetic compounds. The present investigation determined the effect of human natural cycle periovulatory follicular (hFF) and oviductal fluids (hOF) on the human sperm AR in dose-response fashion using the synchronous AR assay. When hFF (30% v/v) or hOF (40% v/v) was added to non-capacitated spermatozoa, no significant (P > 0.05) increase in the % AR was detected in comparison to the non-treatment control. When either of these compounds was added (10%, 20%, and 30% v/v hFF; 20%, 30%, and 40% v/v hOF) to capacitated spermatozoa (3 hour incubation), a significant (P < 0.05) stimulation of the AR was detected. Bovine oviductal fluid (bOF) was tested (20%, 30%, and 40% v/v) to determine if it might have an effect similar to hOF. In contrast to hOF, the highest concentration of bOF (40% v/v) tested failed to stimulate a significant (P > 0.05) increase in the % AR of capacitated spermatozoa in comparison to control. Inhibitors of protein kinases A (KT5720) and C (calphostin C) were tested to determine their effects on the hFF-induced AR. In comparison to hFF treatment alone, the kinase A inhibitor KT5720 (50 nM, 100 nM) prevented hFF (20%) stimulation of the AR when added at the end of the capacitation period and 5 minutes prior to the addition of inducer. Similarly, the kinase C inhibitor calphostin C (50 nM, 100 nM) prevented hFF (20%) stimulation of the AR. The present data demonstrate that periovulatory hFF and hOF stimulate the human sperm AR.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMedDate not supplied

A morphometric comparison of the nuclear morphology of fresh and frozen-thawed human zona-bound and unbound sperm.

The role of sperm nuclear morphology in zona binding and the effect of cryopreservation on sperm nuclear morphology have been investigated using objective criteria. The nuclear dimensions of fresh and frozen-thawed sperm heads that had been prepared by the swim-up (SU) technique, and bound to human oocytes in vitro, were measured using a computer-assisted image analyzer. These were compared with each other and also to sperm in the SU samples and those that had not bound to the zona pellucida. The unbound (UB) sperm and SU sperm had very similar nuclear morphology. In contrast, the nuclear morphology of the zona-bound (ZB) sperm differed significantly (P < 0.05) from that of the SU and UB sperm. These differences were found specifically between area, breadth, and roundness in the SU and ZB sperm preparations, and between area and roundness in the UB and ZB sperm preparations; the ZB sperm had smaller but rounder nuclei than either the SU or UB sperm. In addition, the frozen-thawed sperm in the SU and UB groups showed a trend towards smaller nuclei than the corresponding fresh groups, whereas the frozen-thawed ZB sperm had significantly (P < 0.05) smaller nuclear dimensions than the fresh ZB sperm. From the present study it appears that the ZB sperm are a morphologically distinct population, although it is not yet clear whether these differences reflect functional events that occur in the sperm head during its maturation or changes at the level of the sperm's DNA after the initial stage of zona binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Nucleus↗
PubMedDate not supplied

Continuous assessment of human spermatozoa viability during cryopreservation.

Cryomicroscopy has enabled direct observation of freezing and thawing of human spermatozoa. When used with a fluorescent viability kit, sperm membrane damage was not apparent down to temperatures of -5 degrees C, but significant damage occurred after thawing (55% of spermatozoa had damaged membranes). Semen samples were cooled or frozen to temperatures (at decrements of 10 degrees C) from 0 degree C to -110 degrees C. At all these temperatures the proportion of live to membrane-damaged cells remained constant. Samples held at temperatures above -30 degrees C were not adversely affected. Below -30 degrees C there was a gradual increase in the proportion of membrane-damaged cells on thaw and a decrease in the number of live cells recovering motility. At temperatures between -50 degrees C and -60 degrees C there was an equal proportion of live motile, immotile, and membrane-damaged cells. It is concluded that some irreversible damage to spermatozoa was a result of freezing processes in cells frozen to -30 degrees C or less, but most of the cryodamage was incurred during thawing, possibly due to recrystallization.

Cell Survival↗