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Biomedical subjects

H W Baker

Publications and source records attributed to H W Baker.

At least 73 records · Page 4Linked to original sources
PubMed1994

Correlation of semen variables and pregnancy rates for donor insemination: a 15-year retrospective.

OBJECTIVE: To determine the validity of the criteria currently used to select fertile sperm donors. DESIGN: Retrospective study of the outcome of donor insemination treatment cycles over a 15-year period. SETTING: The Reproductive Medicine Clinic of Prince Henry's Institute of Medical Research (formerly Medical Research Centre, Prince Henry's Hospital, South Melbourne, Victoria, Australia). PATIENTS: Couples (1,299) presented with severe male factor infertility (azoospermia or severe oligozoospermia) and were treated by donor insemination (10,796 treatment cycles) using cryopreserved semen from 292 normal healthy men aged between 18 and 46 years as sperm donors. MAIN OUTCOME MEASURES: Semen characteristics, including volume, count, motility, motility index, normal morphology, live cells, and post-thaw motility, were analyzed by logistic regression analysis to determine which groups of factors were related independently and significantly to pregnancy rates. RESULTS: The pregnancy rate for donor insemination was 8.9% per cycle. By logistic regression count, normal morphology, post-thaw motility (%), and post-thaw motility index together explained 28% of the variance of the pregnancy rates. Other factors, including prethaw motility characteristics (percent motility and motility index), donor age, weight, LH, FSH, and T levels, were not significant. CONCLUSIONS: The standard parameters of sperm count, morphology, and post-thaw motility are the most important factors for the selection of highly fertile donors. As most of the variability in the pregnancy rates resulted from other undetermined factors related both to the donor and the recipient, it is suggested that the pragmatic approach of discarding donors after a reasonable number of treatment failures (20 to 50) should continue.

Cryopreservation↗
PubMed1994

A simple technique to prevent retrograde ejaculation during assisted ejaculation.

The aim of this study was to develop a technique which would prevent retrograde ejaculation in chronic spinal cord injured (SCI) patients undergoing vibration and electroejaculation procedures. A balloon catheter was used to tamponade the bladder neck in 12 patients who underwent 100 assisted ejaculation procedures. Antegrade ejaculations were collected on all occasions with no incidences of urine contamination and no sperm were seen in post ejaculatory urine. Silicone catheters had minimal effects on sperm motility and viability. All lubricant gels were found to adversely affect sperm quality and were not used.

Adult↗
PubMed1994

A new test for the assessment of sperm-zona pellucida penetration: relationship with results of other sperm tests and fertilization in vitro.

The spermatozoa of some patients attending for in-vitro fertilization (IVF) fail to penetrate the zona pellucida in vitro. A test has been devised to identify these cases. It is based on the number of spermatozoa penetrating into the zona pellucida, which were counted after removing spermatozoa bound to the zona surface by vigorous aspiration of each oocyte through a narrow gauge (120 microns) glass pipette. The oocytes were collected from 197 patients undergoing IVF treatment with their own gametes; 79 with no oocytes fertilized and 118 with some oocytes fertilized. Sperm motility, morphology and DNA normality (acridine orange stain) were also measured. The relationships between sperm test results and IVF rate were examined by logistic regression. The proportions of penetrated zonae, normal sperm morphology and normal DNA were the most significant factors related to IVF rate in the whole group. Also, in patients with > or = 30 spermatozoa bound per zona pellucida or with normal sperm morphology > or = 30%, the proportion of penetrated zonae and normal DNA were most significant. Oocytes from 42 patients who had zero fertilization and low sperm-zona binding (average, 2.2 spermatozoa/zona pellucida) were re-incubated with normal donor spermatozoa: large numbers of spermatozoa bound (average, 88 spermatozoa/zona pellucida) and each zona was penetrated by at least one spermatozoon. In conclusion, the percentage of zonae penetrated was the variable most significantly correlated with IVF rate. Penetration of the zona was also strongly related to fertilization rates in patients without defects of sperm morphology and sperm-zona binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Acrosome status and morphology of human spermatozoa bound to the zona pellucida and oolemma determined using oocytes that failed to fertilize in vitro.

It is known that only acrosome-reacted spermatozoa can fuse with the oolemma during normal fertilization with zona pellucida-intact oocytes. The aim of this study was to determine if the oolemma of human zona pellucida-free oocytes selectively binds spermatozoa with normal morphology and a reacted acrosome. Oocytes that failed to fertilize in vitro because of severe sperm defects were used. The zona pellucida was removed with acidic (pH 2-3) saline. Sperm samples were obtained from normal fertile donors and normozoospermic men. Motile spermatozoa were selected with a swim-up technique and 2 x 10(6)/ml incubated with oocytes. The results from 23 experiments showed that at 2 h there was a significantly higher mean percentage of acrosome-reacted spermatozoa bound to the zona pellucida (mean +/- SD, 42 +/- 22) than in the insemination medium (27 +/- 12). In contrast, all spermatozoa bound to the oolemma at 2 h were acrosome reacted. Furthermore, each fresh zona pellucida had > 100 spermatozoa bound compared with an average of 28 (range 4-81) spermatozoa bound per zona pellucida-free oocyte. There was no significant difference in the zona pellucida-induced acrosome reaction between fresh (45 +/- 21) and salt-stored (35 +/- 22) zonae pellucidae. The percentage with normal morphology was significantly higher for spermatozoa bound to the zona pellucida (84 +/- 13) and oolemma of zona pellucida-free oocytes (71 +/- 25) than for spermatozoa in insemination medium (39 +/- 11) (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1994

The use of anticlusterin monoclonal antibodies for the combined assessment of human sperm morphology and acrosome integrity.

Clusterin is an abundant protein in the human male reproductive tract which appears to be produced by the testis, epididymis and the seminal vesicles. Using monoclonal antibodies and an amplified immunoperoxidase technique, we have identified two apparently biochemically distinct forms of clusterin on human spermatozoa. Morphologically abnormal spermatozoa have an extensive surface coating of conventional 80 kDa native clusterin, but this form of clusterin is not detectable on normal spermatozoa. Normal spermatozoa, however, contain within the acrosomal cap a different form of clusterin, reactive with an anticlusterin alpha-chain antibody. Agglutinated spermatozoa, most of which are grossly abnormal, were intensely labelled with the antibody against conventional 80 kDa clusterin, suggesting that the 'clustering' properties of this protein may play a role in the aggregation of abnormal spermatozoa. Anticlusterin monoclonal antibodies may be useful for semen analysis. Staining spermatozoa with anticlusterin monoclonal antibodies is a technically simple method which provides a visually obvious means of assessing spermatozoa morphology and acrosome status simultaneously. The current data also suggest that different functions of clusterin in the reproductive tract may be attributed to different molecular forms of the protein.

Acrosome↗
PubMed1994

Relationship between stimulated hyperactivated motility of human spermatozoa and pregnancy rate in donor insemination: a preliminary report.

The proportion of spermatozoa exhibiting the vigorous motility behaviour termed 'hyperactivation' (HA) has been shown to be increased following removal of seminal plasma and stimulation with chemical agents such as pentoxifylline. The aim of this study was to examine the relationship between the proportion of HA in cryopreserved semen samples from sperm donors and the corresponding pregnancy rates achieved by donor insemination. Cryopreserved samples from 20 men were incubated in the presence or absence of 3 mM pentoxifylline for 1 h and the %HA determined in each sample. The relationship between pregnancy rate, the proportion of HA spermatozoa in control and pentoxifylline-treated groups and the change in %HA following pentoxifylline treatment (delta HA) as well as the mean semen characteristics for each donor [sperm count, motility (%), motility index, normal morphology (%), post-thaw motility (%) and post-thaw motility index] were examined by logistic regression of the occurrence of clinical pregnancy with each insemination. Both delta HA and mean post-thaw motility index were significantly related to pregnancy rates and together accounted for 64% of the observed variation in pregnancy rates.

Cryopreservation↗
PubMed1994

Disordered acrosome reaction of spermatozoa bound to the zona pellucida: a newly discovered sperm defect causing infertility with reduced sperm-zona pellucida penetration and reduced fertilization in vitro.

It is believed that during the process of human fertilization, acrosome-intact spermatozoa bind to the surface of the zona pellucida which triggers the acrosome reaction and the enzymes released facilitate sperm penetration through the zona pellucida. We describe here reduced frequency of the acrosome reaction on the zona pellucida as a cause of infertility in 10 couples with long durations of infertility (average 6 years) and low (< 15%, n = 3) or zero (n = 7) fertilization rates in vitro. Sperm concentration, motility, velocity (Hamilton-Thorn), morphology and DNA normality were within the normal range in all the patients. Electron microscopy of spermatozoa did not reveal any specific ultrastructural defects. All couples were negative for antisperm antibodies by immunobead tests. Oocytes from other patients which failed to fertilize in in-vitro fertilization and normal donor spermatozoa were used as controls for sperm-zona pellucida binding and penetration experiments. Acrosome status of spermatozoa bound to the zona pellucida was assessed with a fluorescent lectin and electron microscopy. The mean number of spermatozoa bound to the zona pellucida was not significantly different between patients and controls. However, the acrosome reaction of spermatozoa bound to the zona pellucida after 2 h incubation was significantly lower (P < 0.001) in the patients (mean 5%, range 0-16) than in the controls (mean 68%, range 44-96). No zona pellucida (out of 40) was penetrated by patient spermatozoa whereas most (39/40) zonae were penetrated by control spermatozoa (average 27 spermatozoa/four zonae pellucidae).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosin↗
PubMed1994

Immunohistological localization of clusterin in the male genital tract in humans and marmosets.

Clusterin is a multifunctional protein, first described in the reproductive tracts of the rat and the ram. It is produced by several cell types and exists in at least two differentially glycosylated forms. The aim of this study was to extend knowledge of clusterin expression in the primate (human and marmoset) male reproductive tracts by means of clusterin-specific immunohistochemical techniques. In both normal and abnormal testicular tissue, clusterin was found in association with Sertoli cells, lumenal sperm, proacrosomal Golgi complexes, residual bodies, and degenerating germ cells. The major differences observed between the two groups were attributable primarily to morphological differences rather than to clusterin expression specifically. There was no correlation between testicular clusterin content and the cause and severity of spermatogenic disorders. Within normal epididymides, regional differences in clusterin staining similar to those reported in the rat were observed. The seminal vesicles contained large amounts of positive clusterin staining, whereas normal human prostate was completely negative. Low levels of clusterin expression were observed in the marmoset prostate. This study suggests that clusterin is an important and widespread product in the human and marmoset reproductive tracts and is likely to have a role in spermatogenesis.

Animals↗
PubMed1994

Male infertility.

Male infertility is a common problem but only about one quarter of patients have specific or defined conditions that make them either sterile or severely infertile. About half of these patients have untreatable primary seminiferous tubule failure, and donor insemination or adoption are the only possibilities of having a family. The other half have potentially treatable conditions, including genital tract obstruction, sperm autoimmunity, gonadotropin deficiency, coital disorders, or reversible toxin effects. The majority of men seen for infertility (75%) have reduced semen quality, which impairs fertility to a variable degree. Thus far no treatments have been shown unequivocally to increase semen quality and fertility in this group. Assisted reproductive technology has improved the outlook for pregnancy in couples with male infertility and the new technique of intracytoplasmic sperm injection promises to further improve results for those with severe sperm defects or previous failure of in vitro fertilization.

Fertilization in Vitro↗
PubMed1994

Fine needle tissue aspiration biopsy of the testis.

OBJECTIVE: To develop a fine needle tissue aspiration biopsy technique that provides sufficient tissue for accurate histological assessment and research purposes. DESIGN: After assessing different needles and developing a method for handling small amounts of tissue, 87 patients underwent fine needle tissue aspiration biopsy. The quantity, quality, and appearance of the tissue was examined and adverse effects of the procedure were noted. Fine needle tissue aspiration and open biopsy samples were compared in 26 patients. Suitability of the tissue for flow cytometry and electron microscopy was also assessed. RESULTS: The 20-gauge, 5-cm Menghini and Turner biopsy needles penetrated the testis more readily and recovered larger quantities of tissue. Adequate samples were recovered from 83% of cases (average of 21.8 tubule sections per testis) with the frequency of recovery and the amount of tissue obtained increasing through-out the study. Some distortions of the tissue were seen but these rarely interfered with the diagnosis. Although many patients suffered slight discomfort during the injection of the anesthetic, no serious complications were encountered during or after the procedure. Comparison of fine needle tissue aspiration and open biopsy diagnoses found either full agreement (56%) or slight differences (38%) in the degree of hypospermatogenesis. CONCLUSIONS: Fine needle tissue aspiration biopsy was found to be a quick, easy, repeatable, and reproducible method of obtaining testicular tissue. No serious adverse effects of the procedure were detected and the diagnoses were found to be comparable to those obtained by open biopsy.

Adult↗
PubMed1993

Lack of association between sperm antibodies and recurrent spontaneous abortion.

The results of this investigation did not confirm the previous report by Witkin and Chaudhry (1). In contrast, they indicate that women with a history of recurrent SABs have a significantly lower incidence of circulating sperm antibodies. This finding is consistent with the considerable amount of evidence indicating that sperm antibodies can interfere with sperm function.

Abortion, Habitual↗
PubMed1993

A controlled study of the psycho-social development of children conceived following insemination with donor semen.

Although donor insemination has been used to produce pregnancies for many years, there has been little information on how children conceived in this unusual manner develop psycho-socially. We have therefore carried out a controlled quantitative assessment comparing children who were conceived by donor insemination to adoptees and naturally conceived children who were matched for age and sex. We conclude that the psycho-social development of donor insemination children was no different from the two control groups.

Adoption↗
PubMed1993

Inhibition of acrosin activity with a trypsin inhibitor blocks human sperm penetration of the zona pellucida.

To evaluate the role of acrosin in human sperm penetration of the zona pellucida (ZP), sperm-oocyte interaction was studied after acrosin activity was blocked with soybean trypsin inhibitor (SBTI). Oocytes that had failed to fertilize because of sperm pathology in a clinical in vitro fertilization program were used to assess sperm binding to and penetration into the ZP. The acrosome reaction of sperm bound to the ZP was determined using fluorescein-labeled Pisum sativum agglutinin after sperm were removed from the ZP. Acrosin activity, determined by a gelatin substrate film method, was severely inhibited by 2 mg/ml SBTI. Sperm motility and movement characteristics, assessed by a Hamilton-Thorn motility analyzer, were unchanged after 6-h incubation with SBTI. Inhibition of acrosin activity did not affect the number of sperm bound to the ZP but completely blocked sperm penetration of the ZP after a 5-h incubation. SBTI did not influence the spontaneous acrosome loss of sperm in culture medium after 6-h and 20-h incubations, but the percentage of acrosome-reacted sperm bound to the ZP was significantly reduced. It was concluded that acrosin activity plays a key role in sperm-zona interaction in humans. Motile sperm are unable to penetrate the ZP when acrosin activity is inhibited. This might result from interference with a phase of the sperm-ZP binding reaction or with a lytic action of acrosin. Also, acrosin may be involved in the acrosome reaction induced by sperm binding to the ZP.

Acrosin↗