Search PubMed⌕ Search

Biomedical subjects

H W Baker

Publications and source records attributed to H W Baker.

At least 55 records · Page 3Linked to original sources
PubMed1996

Relationship between the zona pellucida (ZP) and ionophore A23187-induced acrosome reaction and the ability of sperm to penetrate the ZP in men with normal sperm-ZP binding.

OBJECTIVE: To determine whether the proportions of sperm undergoing the acrosome reaction (AR) on the zona pellucida (ZP) or on exposure to the calcium ionophore A23187 correlate with sperm-ZP penetration in men with normal sperm-ZP binding. DESIGN: Sperm samples from 14 fertile, 50 normozoospermic, and 21 teratozoospermic men with normal sperm-ZP binding were used to study ZP and ionophore-induced AR and sperm-ZP penetration. SETTING: University research unit associated with a clinical infertility and IVF program. MAIN OUTCOME MEASURES: The proportion of sperm undergoing the AR induced by ZP and A23187, the number of sperm bound to and penetrating into the ZP, the proportion of ZP penetrated by sperm, and semen characteristics were analyzed. RESULTS: There were highly significant correlations between the percentage AR of sperm bound to the ZP and both the proportion of ZP penetrated and average number of sperm penetrating per ZP (Spearman r = 0.697 and 0.703). In contrast, A23187-induced AR did not correlate with either ZP-induced AR or sperm-ZP penetration. Although sperm concentration in semen correlated with both ZP-induced AR and sperm-ZP penetration by Spearman test, it was not significant in multivariate regression analyses. CONCLUSION: Ionophore A23187-induced AR does not correlate with either ZP-induced AR or sperm-ZP penetration. The ZP-induced AR is correlated highly with sperm-ZP penetration. Testing ZP-induced AR may be useful for assessing infertile men with normal sperm-ZP binding. In particular, it will identify failure of ZP penetration because of specific defects of the AR on the ZP.

Acrosome↗
PubMed1996

Testicular aspiration of sperm for intracytoplasmic sperm injection: an alternative treatment to electro-emission: case report.

The quantity and quality of spermatozoa produced by electro- or vibro-ejaculation in spinal cord injury patients is often poor, thus advanced reproductive techniques are required if pregnancy is to be achieved. On other occasions no spermatozoa are obtained. We present a successful case of pregnancy achieved using spermatozoa aspirated directly from the testicle combined with intracytoplasmic sperm injection in an in vitro fertilization cycle. We propose this as an alternative to electroejaculation in selected patients.

Adult↗
PubMed1996

A simple method for assessment of the human acrosome reaction of spermatozoa bound to the zona pellucida: lack of relationship with ionophore A23187-induced acrosome reaction.

Acrosome reactions induced by the calcium ionophore A23187 and zona pellucida (ZP) were studied. Sperm samples were obtained from fertile men or men with normal semen analysis and normal sperm-ZP binding. Oocytes were obtained, with the consent of the patients, after the failure of fertilization in vitro. Motile spermatozoa selected by a swim-up technique were incubated with 10 microM A23187 for 1 h, four oocytes for 2 h or solubilized ZP (4 ZP/microliters) for 2 h. Spermatozoa bound to the ZP were dislodged and collected in a small volume of phosphate-buffered saline by aspirating the oocytes with a glass pipette with an inner diameter (120 microns) slightly smaller than the diameter of the oocyte. The acrosome status of the spermatozoa was determined using fluorescein-labelled Pisum sativum agglutinin. The proportion of spermatozoa undergoing the acrosome reaction on the ZP at 2 h varied over a wide range (5-99%), but the agreement between results for the same semen sample exposed to different groups of oocytes was good: the standard deviations of the differences being 9%. Pre-incubation of spermatozoa for 2 h did not increase the ZP-induced acrosome reaction. Re-incubation of ZP with the same sperm suspension for 2 h after removing ZP-bound spermatozoa from the first 2 h incubation produced a significantly lower ZP-induced acrosome reaction in the second incubation (22 +/- 16%) than in the first incubation (30 +/- 14%; P < 0.001, n = 20). There was no significant difference in the ZP-induced acrosome reaction with oocytes with ZP which had or had not been penetrated by spermatozoa during the in-vitro fertilization insemination. Pre-incubation of spermatozoa with solubilized ZP blocked sperm-ZP binding. However, the acrosome reaction induced by solubilized ZP (4 ZP/microliters) was significantly lower than the acrosome reaction induced by intact ZP (10 +/- 5 and 30 +/- 13% respectively, n = 11, P < 0.001), but there was a high correlation (Spearman r = 0.822, P < 0.01) between the results. On the other hand, although the average of the acrosome reaction was similar for A23187 (42%) and for ZP (43%), there was no significant correlation between the results for the two stimuli (n = 60). In conclusion, a useful method for assessing the ZP-induced acrosome reaction has been developed using oocytes which failed to fertilize in vitro. The lack of a relationship between the result of the chemical (A23187) and physiological (ZP) stimuli for the acrosome reaction in the same subjects questions the biological basis of using A23187 for tests of sperm function. Solubilized human ZP in a concentration that blocks sperm-ZP binding is a less efficient inducer of the acrosome reaction than is intact ZP. It is possible that the three-dimensional structure of the ZP is important for induction of the acrosome reaction or that spermatozoa which bind to the ZP are more likely to acrosome react. Assessment of the physiological acrosome reaction for diagnosis of sperm defects which interfere with the fertilization process should be concentrated on the spermatozoa which are capable of binding to the ZP.

Acrosome↗
PubMed1996

Substantial prevalence of microdeletions of the Y-chromosome in infertile men with idiopathic azoospermia and oligozoospermia detected using a sequence-tagged site-based mapping strategy.

Genes on the long arm of Y (Yq), particularly within interval 6, are believed to play a critical role in human spermatogenesis. Cytogenetically detectable deletions of this region are associated with azoospermia in men, but are relatively uncommon. It has been hypothesized that microdeletions of Yq may account for a significant proportion of men with infertility. The objective of this study was to validate a sequence-tagged site (STS)-mapping strategy for the detection of Yq microdeletions and to use this method to determine the proportion of men with idiopathic azoospermia or severe oligozoospermia who carry microdeletions in Yq. STS mapping of a sufficiently large sample of infertile men should also help further localize the putative gene(s) involved in the pathogenesis of male infertility. Genomic DNA was extracted from peripheral leukocytes of 16 normal fertile men, 7 normal fertile women, 60 infertile men (50 of whom had azoospermia and 10 of whom had severe oligozoospermia with no other recognizable cause of infertility), and 15 patients with the X-linked disorder, ichthyosis. PCR primers were synthesized for 26 STSs that span Yq interval 6. None of the 16 normal men of known fertility had microdeletions. Seven normal fertile women failed to amplify any of the 26 STSs, providing evidence of their Y specificity. No microdeletions were detected in any of the 15 patients with ichthyosis. Of the 60 infertile men typed with 26 STSs, 11 (18%; 10 azoospermic and 1 oligozoospermic) failed to amplify 1 or more STS. Interestingly, 4 of the 11 patients had microdeletions in a region that is outside the Yq region from which the DAZ (deleted in azoospermia gene region) gene was cloned. In an additional 3 patients, microdeletions were present both inside and outside the DAZ region. In 3 subjects, the microdeletions were verified by Southern analysis using labeled PCR products corresponding to the deleted STSs as probes. These data suggest a high prevalence (18%) of Yq microdeletions in men with idiopathic azoospermia/severe oligospermia. The physical locations of these microdeletions provide further support for the concept that a gene(s) on Yq deletion interval 6 plays an important role in spermatogenesis. The presence of deletions that do not overlap with the DAZ region suggests that genes other than the DAZ gene may also be implicated in the pathogenesis of some subsets of male infertility.

Adult↗
PubMed1995

Normal fertilization and embryo development by intracytoplasmic sperm injection of round-headed acrosomeless sperm.

OBJECTIVE: To investigate the ability of round-headed acrosomeless sperm to bind to the human zona pellucida (ZP) and oolemma and to fertilize human oocytes by intracytoplasmic sperm injection. DESIGN: Oocytes that had failed to fertilize in IVF were used for sperm-ZP and spermoolemma binding tests. Sperm from a fertile donor was used as a control for oocyte variability. Intracytoplasmic sperm injection was used for assisted fertilization. SETTING: University- and hospital-based reproductive research laboratory and tertiary referral IVF program. PATIENTS: Case study of a couple in which the man has 100% round-headed acrosomeless sperm in the ejaculate. MAIN OUTCOME MEASURE: Fertilization and embryo development and the ability of sperm to bind to the ZP and oolemma. RESULTS: No ZP or oolemma binding was achieved, but normal fertilization and embryo development was obtained after intracytoplasmic injection of round-headed acrosomeless sperm. However, no pregnancy was achieved after the transfer of two cleaving embryos. CONCLUSIONS: Normal fertilization and embryo development from round-headed acrosomeless sperm is possible with intracytoplasmic sperm injection. However, it remains to be reported whether pregnancy can result from fertilization with this type of sperm defect.

Acrosome↗
PubMed1995

Intracytoplasmic sperm injection: a major advance in the management of severe male subfertility.

OBJECTIVE: To determine the success of intracytoplasmic sperm injection for severe male infertility. DESIGN: A retrospective survey. SETTING: A tertiary infertility service. PATIENTS AND INTERVENTIONS: One hundred fourteen couples had 119 intracytoplasmic sperm injection treatments because of previous failure of standard IVF, poor results with subzonal insemination, sperm concentration < 2 x 10(6)/mL, other sperm defects, or male genital tract obstruction. MAIN OUTCOME MEASURES: Fertilization, implantation, and pregnancy rates. RESULTS: Of 1,185 oocytes treated by intracytoplasmic sperm injection, normal fertilization and cleavage occurred in 717 of 1,073 that survived (67% normal fertilization rate). Abnormal fertilization occurred in 113 oocytes (11% abnormal fertilization rate) and 112 oocytes did not survive the procedure (survival rate of 90%). In 117 couples, 251 embryos were transferred fresh, 409 embryos were cryopreserved, and 224 were transferred after thawing. The implantation rate was 7.4% (fetal heart per embryo transferred). To date 36 clinical pregnancies have been achieved (12% per fresh transfer, 20% per frozen transfer, and 30% overall), 24 are ongoing or delivered (6% per fresh transfer, 14% per frozen transfer, and 20% per intracytoplasmic sperm injection). The fertilization rates were the same (65%) with various sperm defects but higher with genital tract obstructions (75%). CONCLUSION: Intracytoplasmic sperm injection has improved the prognosis of severe male infertility.

Cytoplasm↗
PubMed1995

Pregnancies after intracytoplasmic injection of sperm collected by fine needle biopsy of the testis.

OBJECTIVE: To investigate the use of intracytoplasmic sperm injection with sperm collected by fine needle biopsy of the testis as a treatment for male genital tract obstruction. DESIGN: Sperm isolated from a fine needle biopsy of the testis were used to inseminate oocytes by intracytoplasmic sperm injection. SETTING: A hospital-based tertiary referral infertility service. PATIENTS: Case studies of two couples in whom the male partner had a genital tract obstruction. MAIN OUTCOME MEASURES: Fertilization and pregnancy. RESULTS: In the first case, 9 oocytes fertilized normally out of 13 injected. After the transfer of fresh (one cycle) and frozen (four cycles) embryos, a single intrauterine fetal heart pregnancy was achieved. In the second case, five oocytes fertilized normally from nine oocytes injected; two embryos were transferred fresh and three were frozen. A single fetal heart intrauterine gestation was obtained after the initial transfer of two fresh embryos. CONCLUSIONS: A high normal fertilization rate and pregnancies are possible with intracytoplasmic sperm injection using sperm collected directly from the testis. Sperm retrieval by fine needle biopsy offers a viable alternative to microsurgical aspiration and is also suitable for treating patients with intratesticular blockage.

Adult↗
PubMed1995

Sperm preparation for intracytoplasmic injection: methods and relationship to fertilization results.

Sperm preparation for intracytoplasmic sperm injection (ICSI) is described and the effect of high speed centrifugation during preparation on fertilization rate is evaluated. No significant differences were found in the 2-pronuclear or abnormal fertilization rates between sibling oocytes injected with sperm prepared by swim-up or mini-Percoll combined with high speed centrifugation. The high fertilization rate obtained with both methods indicates that high speed centrifugation is not necessary to prepare sperm for ICSI. Fertilization rates were also compared for sperm obtained from ejaculates, fresh and frozen epididymal aspirates, and testicular biopsies. High fertilization rates were obtained from all groups but they were significantly higher in those oocytes injected with epididymal sperm (78% per oocyte surviving injection). The high fertilization rate with epididymal sperm may reflect sperm quality or may result from the method of sperm preparation for injection. Fertilization after the injection of sperm from which the tail was dislodged during immobilization was compared with that obtained using intact sperm. A significantly lower rate of 2-pronuclear fertilization was found in those oocytes injected with sperm heads only (55%) compared with intact sperm (68%), although cleavage rates between the two groups were similar. The use of hypo-osmotic medium to select potentially live sperm from an immotile sample is also described and fertilization was obtained after the injection of sperm with a structural defect which were selected using this technique. These results indicate that high fertilization rates can be obtained with ejaculated, epididymal and testicular sperm without special treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗
PubMed1995

The use of intracytoplasmic sperm injection for the treatment of severe and extreme male infertility.

The outcome of treatment by intracytoplasmic sperm injection (ICSI) is described for patients with severe male infertility. In 296 consecutive cycles, a normal fertilization rate of 69% was achieved with 288 cycles (97%) resulting in embryos suitable for transfer. A total of 32 clinical pregnancies were achieved from the transfer of fresh embryos (clinical pregnancy rate of 12% per transfer) and an additional 44 clinical pregnancies were obtained after the transfer of frozen-thawed embryos (clinical pregnancy rate of 16% per transfer). Overall, 57 of the 76 pregnancies were ongoing or delivered. An analysis of outcome in 5 male factor subgroups revealed no significant differences in pregnancy and implantation rates between the categories. However, the fertilization rate was significantly lower in patients with oligoasthenoteratozoospermia and significantly higher in those patients for whom epididymal sperm were used for insemination. The treatment of patients with extreme male infertility is also described; normal fertilization and embryo development were obtained using ICSI in patients with mosaic Klinefelter's syndrome, severe sperm autoimmunity, round-headed acrosomeless sperm (globozoospermia), completely immotile sperm selected by hypo-osmotic swelling and sperm isolated from testicular biopsies. Three ongoing pregnancies were obtained from 6 patients for whom testicular sperm were used. These results demonstrate the value of ICSI in the management of severe male infertility, however, the treatment of some types of extreme male infertility using ICSI may be limited.

Autoimmune Diseases↗
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↗
PubMed1995

Ability of spermatozoa to bind to the zona pellucida during oligozoospermia induced with testosterone during a male contraceptive trial.

To determine the ability of spermatozoa to bind to the zona pellucida (ZP) in testosterone-induced oligozoospermia, previously fertile men participating in the World Heath Organization (WHO) male contraceptive trial in Melbourne were studied while oligozoospermic to various degrees. Semen analysis were performed according to WHO methods. One or two ejaculates from each subject were cryopreserved before commencing weekly intramuscular injections of 200 mg testosterone enanthate. The frozen spermatozoa were used as controls for ZP-binding tests of spermatozoa obtained during testosterone-induced oligozoospermia (< 10 x 10(6)/ml) in either the suppression or efficacy (n = 6) and recovery (n = 3) phases. Two other subjects in the recovery phase with normozoospermia were also tested. Human oocytes that failed to fertilized in vitro from infertile patients were used for the sperm-ZP binding test. Control (frozen) spermatozoa were labelled with fluorescein isothiocyanate and test (oligozoospermic semen) spermatozoa were labelled with tetramethylrhodamine B isothiocyanate. A mixture of equal numbers of labelled motile control and test spermatozoa were incubated with 4-6 ZP. There was a significantly (p < 0.01) lower number of spermatozoa bound per ZP in oligozoospermic samples (65 +/- 7, mean +/- SEM) than in controls (80 +/- 7). However, there were still large numbers of spermatozoa bound to the ZP for all the oligozoospermic samples. Five subjects had similar numbers of spermatozoa bound to the ZP for both control and oligozoospermic samples. Overall, the ZP-binding ratio of test and control spermatozoa averaged 0.82 (range 0.51-1.13).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Assessment of the Sperm Quality Analyzer.

OBJECTIVE: To assess the relationship between the results of the Sperm Quality Analyzer (United Medical Systems Inc., Santa Ana, CA), which measures motile sperm concentration by light scattering, conventional manual semen analysis characteristics, and computer-assisted sperm motility analyses. DESIGN: Sperm Quality Analyzer measurements and manual and computer-assisted semen analyses were performed on 150 (50, 62, and 38) samples in three laboratories and the results were compared. SETTING: The study was performed in the Andrology Laboratory of Prince Henry's Institute of Medical Research, Monash Medical Centre, and Andrology Laboratory and Reproductive Biology Unit at the Royal Women's Hospital, Melbourne, Victoria, Australia. PATIENTS: Patients presented to the laboratories for routine fertility evaluation in the male and were selected at random to reflect the range of normal and abnormal samples seen in the laboratories. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Sperm count, motility (percent motility, motility index, velocity, and amplitude of lateral head displacement [ALH]), morphology, and normal acrosomes were evaluated by manual and computer-assisted semen analysis and sperm quality analyzer motility index. RESULTS: Spearman nonparametric univariate analysis showed strong correlations between sperm motility index and manual sperm concentration, motility, abnormal morphology, and normal acrosomes by Pisum sativum agglutinin; and computer-assisted sperm motility analysis sperm concentration, motile concentration, and percent static. Curvilinear velocity, straight-line velocity (VSL), and linearity also were related significantly to sperm motility index values. By multiple regression analysis, the significant covariates of the sperm motility index were motile sperm concentration, abnormal morphology, ALH, and straight-line velocity and these accounted for 85.5% of the variance of the sperm motility index. CONCLUSIONS: The Sperm Quality Analyzer is easy to use. The good correlation between the sperm motility index, motile sperm concentration, and, in addition, a number of other semen parameters supports the use of the Sperm Quality Analyzer for screening patients and in situations that warrant a rapid verification of semen quality, such as in the IVF or artificial insemination clinic. Further investigation of the Sperm Quality Analyzer in the management of male infertility is warranted.

Acrosome↗
PubMed1995

A new fully automated system for the morphometric analysis of human sperm heads.

OBJECTIVE: To develop a fully automated image analysis system to provide objective, quantitative, and reproducible assessment of the head morphology of human spermatozoa. DESIGN: Shorr-stained smears of washed sperm were imaged with a microscope (x100) and black and white video camera and digitized for computer analysis. Automatically selected sperm head images are analyzed in terms of 32 parameters that reflect size, shape, and staining heterogeneity. Unique features of the analysis include extraction of a 40% density contour in addition to the usual boundary contour and parameterization of optical density profiles. The morphometry of a semen sample is summarized by evaluation of the sample mean and standard deviation for each morphometric parameter. In addition, each analyzed sperm in a sample is assessed for conformity to a reference morphometric data set. RESULTS: The system filters seminal debris, superimposed cells, and lysed sperm, with an average sperm recognition error of 2.3% and contour interpretation error of 1.7%. The average proportion of variance attributable to slide preparation and analysis methods (2.6%) was low relative to that between infertility patients (12.4%). The relatively slow assessment times would be improved substantially with upgraded hardware. CONCLUSION: The precision and sensitivity offered by the detailed image analysis of this system provides a powerful tool for morphometric semen analysis.

Autoanalysis↗
PubMed1995

Fertilization and pregnancy with acrosome intact sperm by intracytoplasmic sperm injection in patients with disordered zona pellucida-induced acrosome reaction.

OBJECTIVE: To determine whether fertilization and pregnancy could be obtained by injection of acrosome-intact sperm into the cytoplasm in patients with persistent failure of fertilization in IVF-ET associated with disordered zona pellucida (ZP)-induced acrosome reaction (AR). DESIGN: Sperm-ZP binding and penetration and ZP-induced AR were compared between patients and fertile donors. Acrosome-intact sperm removed from the ZP were injected into the cytoplasm of the oocytes. SETTING: Reproductive Biology Unit, Royal Women's Hospital. MAIN OUTCOME MEASURES: The proportion of ZP penetrated and ZP-induced AR and fertilization and pregnancy after intracytoplasmic sperm injection were analyzed. RESULTS: Most (7/8) of the patients had consistently normal sperm characteristics including concentration, motility and velocity, acrosomes, and morphology. Mean number of sperm bound to the ZP was not significantly different between patients (97 sperm/ZP) and fertile donor controls (100 sperm/ZP). However, AR of sperm bound to the ZP was significantly lower in the patients (4%) than in controls (61%). None of the ZP (n = 32) were penetrated by patient sperm whereas all (n = 32) ZP were penetrated by control sperm. Acrosome intact sperm removed from the ZP were used for intracytoplasmic sperm injection. All patients had > or = 50% normal fertilization and embryo development. Three pregnancies (one early aborted, two ongoing) were achieved after the transfer of fresh or frozen embryos. CONCLUSION: Acrosome-intact human sperm can produce a high fertilization rate and pregnancies after intracytoplasmic sperm injection in patients with disordered ZP-induced AR. The acrosome reaction is unlikely to be important for fertilization with intracytoplasmic sperm injection.

Acrosome↗
PubMed1994

Collection of semen from men in acute phase of spinal cord injury.

In chronic spinal cord injury, semen obtained by assisted ejaculation is usually abnormal. We have assessed electroejaculation early after injury in seven patients. There were no adverse effects. Initial samples contained few or no spermatozoa but as patients emerged from spinal shock, semen improved and five had specimens cryopreserved. Thereafter sperm motility and viability decreased towards the pattern of chronic spinal cord injury by day 16. Cryopreservation was not possible in one patient with many medical complications and another who started electroejaculation 15 days after injury. Semen storage within the first 2 weeks after spinal cord injury is recommended for future fertility treatment.

Acute Disease↗