Search PubMed⌕ Search

Biomedical subjects

D S Irvine

Publications and source records attributed to D S Irvine.

At least 19 recordsLinked to original sources
PubMed1997

Field trial of a diluent for the transportation of human semen at ambient temperatures.

OBJECTIVE: To examine the ability of a citrate-yolk buffer extender to preserve human semen samples at ambient temperatures over a 25- to 30-hour period. DESIGN: Human semen samples were diluted 1:1 with citrate-yolk buffer or homologous seminal plasma and transported at ambient temperature between two distant locations (London to Edinburgh, United Kingdom). Various criteria of semen quality then were assessed before and after 25 to 30 hours storage and transportation in these diluents. SETTING: An institutional research laboratory and a private fertility clinic. PATIENT(S): Samples were provided by 21 donors of unknown fertility and 7 asthenozoospermic patients. INTERVENTION(S): The diluent used to preserve human semen comprised an egg yolk buffer supplemented with fructose and citrate. MAIN OUTCOME MEASURE(S): Aspects of semen quality assessed included movement, hyaluronate penetration, viability, acrosome reaction, and reactive oxygen species generation. RESULT(S): The deterioration of semen quality at ambient temperatures could be prevented by the presence of citrate-yolk buffer, permitting the accurate analysis of oxidative stress and human sperm function, 25 to 30 hours postejaculation. CONCLUSION(S): Citrate-yolk buffer offers considerable promise as a medium for the ambient temperature storage and transportation of human semen.

Acrosome↗
PubMed1996

The extragenomic action of progesterone on human spermatozoa is influenced by redox regulated changes in tyrosine phosphorylation during capacitation.

Capacitation had no effect on the ability of progesterone to elicit a rapid calcium transient in the acrosomal domain of human spermatozoa but had a marked influence of the ability of this steroid to induce a biological response. The development of this responsiveness to progesterone appeared to be redox regulated in that it was promoted by the stimulation of reactive oxygen species generation and inhibited by the presence of antioxidants, including catalase and membrane permeant thiols. The ability of redox conditions to influence the biological responsiveness of human spermatozoa did not involve changes in the dynamics of the calcium transients induced by progesterone but was causally linked with clear differences in tyrosine phosphorylation. We conclude that the ability of human spermatozoa to respond to the calcium transients induced by progesterone depends on a background of phosphotyrosine expression that can be profoundly influenced by the redox status of the spermatozoa during capacitation.

Humans↗
PubMed1996

Superoxide dismutase in human sperm suspensions: relationship with cellular composition, oxidative stress, and sperm function.

Sensitive techniques have been developed for monitoring superoxide dismutase (SOD) activities in human sperm preparations. In contradiction to the protective role normally assigned to SOD, populations of defective spermatozoa recovered from the low density region of Percoll gradients were found to have three times more SOD than functionally competent preparations pelleting in high density Percoll. SOD activity was negatively correlated with the movement characteristics of human spermatozoa and their capacity for oocyte fusion, and positively associated with the induction of peroxidative damage. SOD activity was also highly correlated with other markers of the cytoplasmic space, creatine kinase (CK), and glucose-6-phosphate dehydrogenase (G-6-PDH). We conclude that while SOD may play a physiological role in maintaining a balance between O2.- and H2O2, high levels of this enzyme are associated with impaired sperm function because (a) the human spermatozoon is highly susceptible to the cytotoxic effects of H2O2, (b) O2.- is an important mediator of normal sperm function, and (c) high SOD activities reflect errors in spermatogenesis associated with germ cell exfoliation and the retention of excess residual cytoplasm by the spermatozoa.

Acrosome↗
PubMed1996

Protective effect of antioxidants on the impairment of sperm motility by activated polymorphonuclear leukocytes.

OBJECTIVE: To test the ability of antioxidants to reduce the loss of sperm motility caused by reactive oxygen species generated by polymorphonuclear leukocytes (PML). DESIGN: Standardized preparations of leukocyte-contaminated semen were created by suspending known concentrations of purified spermatozoa and PML in seminal plasma. After the stimulation of reactive oxygen species generation with phorbol ester, the spermatozoa were washed and incubated in culture medium before an analysis of their movement. The ability of antioxidants to counteract the free radical-induced loss of sperm motility observed under these circumstances was assessed. SETTING: An institutional research laboratory. PARTICIPANTS: The semen was obtained from normal volunteers. INTERVENTIONS: The following were tested: vitamins C and E, dimethylsulfoxide, catalase, hypotaurine, N-acetylcysteine, and reduced glutathione. MAIN OUTCOME MEASURES: Reactive oxygen species generation was monitored by luminol-dependent chemiluminescence. Sperm motility was assessed manually and by computer-aided semen analysis. RESULTS: Consistent impairment of sperm motility and average path velocity was observed in the presence of activated PML. This effect was reduced by the concomitant presence of glutathione, N-acetylcysteine, hypotaurine, and catalase. CONCLUSION: Antioxidants can protect against the damaging effect of leukocyte-derived reactive oxygen species on sperm movement and may be of clinical value in assisted conception procedures.

Antioxidants↗
PubMed1996

Studies on the development of diluents for the transportation and storage of human semen at ambient temperature.

Storage of human semen samples at ambient temperature for 24 h resulted in a significant loss of sperm motility from a mean 45.1 +/- 1.8% to 13.8 +/- 1.1% (n = 148). This motility loss was associated with a significant increase in the osmolality of the seminal plasma and the induction of peroxidative damage to the spermatozoa. Both of these detrimental changes could be prevented by diluting the original semen sample 1:1 with a citrate-egg yolk, buffer (CYB). In the presence of this extender all aspects of semen quality were efficiently preserved for 24 h, including sperm movement, penetration of a cervical mucus substitute, the acrosome reaction and sperm-oocyte fusion. CYB extension also permitted the use of chemiluminescent tests of leukocyte contamination to be performed on semen samples stored for 24 h at ambient temperatures. As a preservation medium, CYB was found to be superior to alternative formulations lacking citrate and storage at ambient temperatures was preferable to 4 degrees C. Significant improvements in motility retention were also observed when CYB was supplemented with pentoxifylline, although this treatment significantly stimulated peroxidative damage in the spermatozoa. However, if the pentoxifylline was combined with antioxidants then this collateral peroxidative damage could be reduced and the performance of CYB significantly enhanced. These results have implications for the design of diluents permitting the long-term storage and transportation of human semen samples at ambient temperatures.

Animals↗
PubMed1996

Prediction of the in-vitro fertilization (IVF) potential of human spermatozoa using sperm function tests: the effect of the delay between testing and IVF.

To examine the diagnostic significance of several criteria of semen quality and to determine whether their prognostic value is eroded by the time interval between assessment and the attempt at in-vitro fertilization (IVF) with embryo transfer, 73 couples undergoing IVF and embryo transfer therapy were studied. The ability of human spermatozoa to achieve fertilization in vitro was examined in relation to the conventional semen profile, sperm morphology, the computer-aided assessment of sperm movement, ionophore-induced acrosome reaction, acridine orange staining, and chemiluminescent signals induced by phorbol ester and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Spermatozoa were examined both in semen and after preparation on Percoll, some weeks prior to IVF. Fertilization rates were noted to be significantly correlated with elements of sperm movement characteristics, sperm morphology, and reactive oxygen species generation. Prediction of fertilization rates in a stepwise multiple regression analysis was obtained using four variables: sperm morphology, FMLP-induced chemi-luminescence and sperm movement characteristics (beat cross frequency and straightness) (r approximately 0.5). When multiple logistic regression analysis was used to predict which samples would achieve fertilization rates above and below a 50% threshold, three variables of predictive value including linearity, average path velocity and FMLP-induced chemiluminescence were selected. Combination of these variables classified the samples achieving good or poor fertilization with an overall accuracy of 83.6%. The time interval between semen assessment and IVF had little effect on the predictive value of these tests. In conclusion, the fertilizing ability of human spermatozoa is related to sperm morphology, attributes of sperm movement and reactive oxygen species production. The time delay between testing and IVF did not appear to affect predictive accuracy.

Acridine Orange↗
PubMed1996

Home ovulation testing in a donor insemination service.

The use of home ovulation testing kits in donor insemination (DI) has been proposed to increase patient and clinic convenience while not compromising fecundity rates. Such a system was introduced into our DI service in December 1994, and we here report an audit of experience over 6 months. Patients were offered home or laboratory luteinizing hormone (LH) testing, and those requesting home testing were asked to store an aliquot of tested urine for subsequent assay in the laboratory allowing retrospective analysis of the accuracy of cycle timing. Insemination using cryopreserved semen was performed on the day home testing predicted ovulation, or on the day an LH surge was detected in the laboratory, and on the following day. Pregnancy rates were significantly reduced in home testers: 3.4% per cycle (174 cycles, 64 women) versus 12.7% (110 cycles, 53 women) over the same time period (P < 0.005, 95% confidence interval 6.5-18.9). Urine samples from 140 cycles from 51 women using home testing were analysed. There were insufficient data in nine to allocate the cycle. Of home tested cycles, 37 (28%) were inseminated on a day other than the first day of the LH surge. In 13 of these insemination was performed after the first day of the LH surge. Incorrect treatment was associated with high baseline LH, but those with 'late' treatment had low basal LH concentrations, similar to those correctly treated. Analysis of individual urine samples showed that the positive predictive value of home testing was 72%. These results suggest that home ovulation testing results in reduced chance of pregnancy, with increased frustration for both patients and clinic staff. This may be particularly so in women with high baseline LH concentrations.

Adult↗
PubMed1996

The extragenomic action of progesterone on human spermatozoa: evidence for a ubiquitous response that is rapidly down-regulated.

Image analysis techniques have been used to demonstrate that progesterone induces a rapid calcium transient in the acrosomal domain of greater than 90% of human spermatozoa (n = 2354). These results are at variance with previous reports, suggesting that progesterone receptors are only expressed on a small subpopulation of these cells, by virtue of their ability to bind fluorescent probes incorporating progesterone 3- (O-carboxymethyl) oxime conjugated to BSA. In the present study, we could confirm that such probes only bound to a small proportion of human spermatozoa (3.01 +/- 0.29%; n = 7557) although 91.79 +/- 1.8% of the same sperm populations exhibited a calcium transient in response to progesterone. These results indicate that the binding of labeled progesterone conjugates to human spermatozoa does not reflect the size of the progesterone responsive population; the response elicited by this steroid is essentially ubiquitous. Progesterone action was shown to involve an influx of extracellular calcium via mechanisms that did not involve voltage sensitive- or second messenger operated-channels, phospholipase C, or G proteins. Despite previous evidence suggesting that progesterone action might involve a GABAA receptor/chloride channel, neither GABA nor the GABA agonist muscimol had any effect on intracellular calcium concentrations in human spermatozoa or influenced their functional competence. The only factor that disrupted the responses of human spermatozoa to progesterone was this steroid itself. Progesterone exposure induced a prolonged period of refractoriness to further stimulation that influenced the capacity of these cells to generate calcium transients, and their ability to exhibit a biological response to changes in intracellular calcium. There are implications in these results for our understanding of the extragenomic action of progesterone on human spermatozoa and the clinical manipulation of this system for the assessment and suppression of human sperm function.

Binding Sites↗
PubMed1995

Predicting the fertilizing potential of human sperm suspensions in vitro: importance of sperm morphology and leukocyte contamination.

OBJECTIVE: To determine the relationships between sperm function tests and fertilization of human oocytes in vitro. DESIGN: Analysis of infertile patients undergoing IVF therapy. SETTING: Diagnostic Andrology Laboratory and Assisted Conception Service. PATIENTS: Forty-one couples who underwent IVF-ET therapy were studied. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The ability of human spermatozoa to achieve fertilization in vitro was examined in relation to numerous criteria of semen quality, including the conventional semen profile, the computer-aided assessment of sperm movement, ionophore-induced acrosome reaction, acridine orange staining, sperm morphology, and chemiluminescent signals induced by phorbol ester and N-formyl-methionyl-leucyl-phenylalanine (FMLP). RESULTS: Significant correlations were observed between fertilization rates and several attributes of the sperm preparations, including elements of sperm function (acrosome reaction), movement (percentage motile, hyperactivation, the amplitude of lateral sperm head displacement), morphology (normal morphology, midpiece defects, multiple anomalies index), nuclear normality (acridine orange staining), and reactive oxygen species generation (chemiluminescence induced by phorbol ester and FMLP). In a stepwise multiple regression analysis, an accurate prediction of fertilization rates was obtained using a multiple regression equation incorporating six variables of which sperm morphology and FMLP-induced chemiluminescence were the most informative. CONCLUSIONS: A set of criteria have been identified that accurately predict the fertilizing potential of human sperm suspensions in vitro and that place particular emphasis on sperm morphology and the degree of leukocyte contamination.

Acridine Orange↗
PubMed1995

Definition of the optimal criteria for identifying hyperactivated human spermatozoa at 25 Hz using in-vitro fertilization as a functional end-point.

Spermatozoa from fertile donors were used to select and validate criteria for the automated classification of hyperactivated (HA) motility using a computer-aided sperm analysis (CASA) system operating at 25 Hz. In the first phase of this analysis, 710 sperm trajectories were analysed and classified as forward progressive (FP), transition phase (TP) or HA. These tracks were then subjected to a CASA analysis and the various attributes of sperm movement defined for each category of motion. From this analysis, criteria were identified and subsequently validated that permitted the automated selection of FP, TP+HA and HA cells, with > 90% accuracy. To determine which attributes of movement best predicted the fertilizing potential of human spermatozoa, a detailed analysis of sperm motion was undertaken in patients undergoing in-vitro fertilization therapy. This analysis indicated that the single most important aspect of sperm movement was the incidence of HA motility (defined as curvilinear velocity > 90 microns/s, linearity < 20%, dancemean [amplitude of lateral head displacement/linearity x 100] > 45.8 microns) after 3 h of incubation. Using the latter criterion as the first incorporated variable, multiple regression equations were created that explained up to 50% of the variance in fertilization rates. None of the other patterns of motion (FP, TP, TP+HA) was correlated with fertilization rates, and none of the other published algorithms for identifying HA cells were as efficient as those described here.

Cohort Studies↗
PubMed1995

The predictive value of computer-assisted semen analysis in the context of a donor insemination programme.

In this paper we examine the value of both conventional and computer-assisted semen analysis (CASA) using the Hamilton-Thorn HTM-S 2030 in predicting the in-vivo fertility of cryopreserved donor semen. Semen samples were examined prospectively and data on the conventional criteria of semen quality, sperm morphometry and movement were collected. Of 61 ejaculates identified, 33 achieved pregnancies ('successful') and 28 failed to do so ('unsuccessful'), despite insemination into at least four different normal female recipients. When the post-thaw semen profiles were compared, no differences were observed between the two groups in respect of the conventional criteria of semen quality determined by conventional laboratory techniques; however, there were differences in respect of both morphometry and movement characteristics determined by the HTM-S. When multiple logistic regression was used to examine the ability of the variables measured to predict the achievement of pregnancy, the conventional criteria of semen quality were of no value (chi 2 = 6.67, P = 0.353). However, the CASA assessment successfully predicted outcome in 86.9% of cases (chi 2 = 44.3, P = 0.0021). It was concluded that CASA assessment is of significant value in predicting the ability of an ejaculate to achieve pregnancy.

Autoanalysis↗
PubMed1995

Analysis of sperm movement in relation to the oxidative stress created by leukocytes in washed sperm preparations and seminal plasma.

The addition of luminol to unprocessed semen samples resulted in the generation of chemiluminescent signals, the intensity of which was highly correlated with the level of leukocyte contamination. Despite the spontaneous oxidant-generating capacity of seminal leukocytes, no correlations were observed between leukocyte contamination and the fertility status of the subjects or any aspect of the semen profile, including the motility of the spermatozoa or their performance in a hyaluronate penetration assay. Luminol-dependent chemiluminescence and leukocyte contamination were also correlated in washed sperm suspensions prepared either by repeated centrifugation or on discontinuous Percoll gradients. However, in such sperm suspensions, the spontaneous generation of oxidants by contaminating leukocytes (> 2 x 10(4) leukocytes/ml) was invariably associated with a decreased capacity for movement. Moreover, causative associations between leukocyte contamination, reactive oxygen species generation, lipid peroxidation and impaired sperm motility were revealed by experiments involving the selective addition or removal of activated leukocytes. From these observations we can conclude that low concentrations of leukocytes are a common feature of the human ejaculate and can impair sperm function, particularly in the absence of seminal plasma. These findings have implications for our understanding of the importance of leukocytospermia in defining the fertility of human spermatozoa in vivo and in vitro.

Antibodies, Monoclonal↗
PubMed1994

A prospective clinical study of the relationship between the computer-assisted assessment of human semen quality and the achievement of pregnancy in vivo.

The objective of this study was to examine the clinical predictive value for the achievement of pregnancy in vivo of the assessment of human semen quality by computer-assisted semen analysis using the Hamilton-Thorn Motility Analyser (HTM-S), alongside classic World Health Organization (WHO) techniques. A prospective follow-up study of 303 couples attending a regional infertility clinic providing tertiary level services to the population of a single geographical region was undertaken. Couples attending the infertility clinic, in whom the female partner was normal on conventional investigations (history, examination, evidence of ovulation, laparoscopy), were studied. After initial assessment, couples were followed for a median of 15 months and treatment-independent pregnancies observed and related to the results of semen assessment. During the period of follow-up, the treatment-independent pregnancy rate was 52%. Several measures of semen quality, determined both manually and by the HTM-S, were found to be predictive of the achievement of pregnancy and were related to the time taken to conceive. Couples who conceived had higher sperm concentrations and motilities, determined both manually and by the HTM-S, as well as differences in sperm head morphometry and sperm velocity determined by the HTM-S. Using multiple logistic regression, the prognostic accuracy of the HTM-S alone was similar to manual techniques, although data from the computer assisted sperm analysis system were preferred. Using proportional hazards regression, several variables were related to the achievement of pregnancy, particularly morphometry and motility. It was concluded that a strong case can be made for the introduction of automated assessment of human semen in routine service andrology laboratories.

Evaluation Studies as Topic↗