PubMed Health⌕ Search

Biomedical subjects

H W Baker

Publications and source records attributed to H W Baker.

At least 91 records · Page 5Linked to original sources
PubMed1993

Body composition and muscle strength in healthy men receiving testosterone enanthate for contraception.

To determine the effect of androgens on body composition and muscle strength, we measured fat-free mass (kg), fat mass (kg), and bone density (g/cm2) by dual x-ray absorptiometry, and muscle strength (Newton meters) by dynamometry in a controlled, prospective study involving 13 nonathletic men receiving testosterone enanthate 200 mg/week in for 6 months and 8 healthy controls. Biochemical markers of bone turnover were measured in the treated subjects at baseline and 6 months. In the treated subjects at 6 months, fat-free mass (mean +/- SEM) increased by 9.6 +/- 1.0% (P < or = 0.01) whereas fat mass decreased by 16.2 +/- 6.7% (P < or = 0.05). Changes in muscle strength ranged from -1.6-19.2%. Only hip adduction increased 19.2 +/- 9.5% (P < 0.05). Changes in bone density ranged from -1.3-5.2%, decreasing significantly at one site and increasing significantly at four of the nine sites measured (P < 0.05). Serum testosterone increased by 91.1 +/- 7.5% (P < 0.01), and testicular volume decreased by 24.0 +/- 3.2% (P < 0.01). Serum osteocalcin increased by 35.7 +/- 17.3% (P < 0.05), serum immunoreactive PTH (iPTH) increased by 41.4 +/- 15.1% (P < 0.05), serum calcium decreased by 2.3 +/- 1.0% (P < 0.05), and serum albumin decreased by 4.5 +/- 1.7% (P < 0.05). There were no detectable changes in fat-free mass, fat mass, muscle strength, or bone density in controls. The administration of testosterone enanthate in pharmacological doses for 6 months resulted in a modest reduction in fat mass and small increases in fat-free mass, muscle strength, and bone density. These changes do not support the use of androgens for enhancing athletic performance.

Absorptiometry, Photon↗
PubMed1992

Tests of human sperm function and fertilization in vitro.

OBJECTIVE: To review recent studies on the development of new tests of human sperm function and evaluation of which sperm characteristics are most important for fertilization in vitro by logistic regression analysis. STUDY SELECTION: Recent studies on the relationship between putative and new tests of human sperm function and fertility in vitro or in vivo are discussed in this review. Some physiological and technical aspects are included. MAIN OUTCOME MEASURES: Fertilization rates in vitro and sperm tests including standard semen analysis, improved morphology assessment, objective assessment of sperm motility and movement characteristics, nuclear maturity, hypo-osmotic swelling, the acrosome and the acrosome reaction, acrosin activity, human sperm-hamster oocyte penetration assay, and sperm-zona pellucida (ZP) and sperm-oolemma binding. RESULTS: The percentages of sperm with normal morphology and a normal intact acrosome, mean linearity, and the number of sperm binding to the ZP were highly significant related to fertilization rates in vitro. Other sperm tests evaluated usually provided no additional information about fertilization rates. The human ZP is highly selective for binding of morphologically normal sperm. Acrosome-reacted human sperm have little or no ability to bind to the ZP. CONCLUSION: Results of in vitro fertilization can be used to evaluate tests of human sperm function. Logistic regression analysis is a powerful method for determining which groups of sperm characteristics are independently related to fertilization rates. Normal morphology, linearity, acrosome status, and sperm-ZP binding are the most important characteristics for fertilization in vitro.

Acrosome↗
PubMed1992

Sperm nuclear chromatin normality: relationship with sperm morphology, sperm-zona pellucida binding, and fertilization rates in vitro.

OBJECTIVE: To study whether the results of tests of sperm chromatin and deoxyribonucleic acid (DNA) normality are related to fertilization rates in vitro. DESIGN: Normal morphology, nuclear maturity determined by acidic aniline blue stain, and DNA normality determined by acridine orange fluorescence of sperm in insemination medium and the number of sperm bound to the zona pellucida (ZP) of the oocytes that had failed to fertilize in vitro were determined. The relationship between sperm test results and fertilization rates were analyzed by logistic regression. SETTING: Samples were obtained from patients undergoing in vitro fertilization (IVF) treatment. RESULTS: The number of sperm bound to the ZP, the percentage of sperm with normal morphology, and the percentage of sperm with normal DNA were the most significant factors related to fertilization rates in vitro. In patients with normal morphology > or = 15% or with > 10 sperm bound per ZP, the percentage of sperm with normal DNA, the number of sperm bound to the ZP, and motility grade were significantly related to IVF rates. CONCLUSION: In patients with normal morphology > or = 15%, failure of fertilization may be because of defects of sperm-ZP binding or abnormal DNA. Assessment of DNA normality of motile sperm in the insemination medium may aid prediction of fertilization rates in addition to normal morphology and sperm-ZP binding.

Acridine Orange↗
PubMed1992

Comparison of Percoll, mini-Percoll and swim-up methods for sperm preparation from abnormal semen samples.

Two methods of density gradient centrifugation, Percoll (P) and mini-Percoll (MP), were compared with the swim-up technique for preparing spermatozoa from each of 40 abnormal semen samples. P and MP produced similar results with a mean recovery of spermatozoa with progressive motility which was significantly higher (18-19%) than that achieved with swim-up (5%). However, the swim-up method resulted in the recovery of spermatozoa with a higher mean motility (89 versus 58%), velocity (69 versus 56 microns/s), percentage with normal morphology (22 versus 16%) and intact acrosomes (61 versus 36%) than P and MP. The mean amplitude of lateral head displacement was the only characteristic of spermatozoa in semen which correlated with the recoveries of motile spermatozoa. Combining MP and swim-up methods for 10 samples produced a higher recovery (11 versus 6.9%) of spermatozoa with significantly better mean motility (94 versus 87%) than did swim-up alone. Although P and MP resulted in greater yields of motile spermatozoa than the swim-up preparation, the latter procedure selected higher proportions of spermatozoa with improved characteristics (velocity, intact acrosomes and normal morphology) which correlate with fertilization rates in vitro. It is concluded that P and MP are not superior to swim-up. However, sequential MP and swim-up preparation improves yields of high quality spermatozoa from some abnormal semen samples and therefore has potential for improving fertilization rates.

Cell Separation↗
PubMed1992

Morphology of spermatozoa bound to the zona pellucida of human oocytes that failed to fertilize in vitro.

The morphology of spermatozoa bound to the zona pellucida (ZP) of 264 oocytes that had failed to fertilize in 58 in vitro fertilization procedures was studied by light microscopy. The percentage of spermatozoa with normal morphology bound to the ZP (mean 77, range 8-100) was significantly higher than in the insemination medium (mean 42, range 2-80). The abnormal spermatozoa bound to the ZP had small oval (47%), pyriform (46%), amorphous (5%) and tapering (2%) heads. Other abnormalities of morphology were not observed in ZP-bound spermatozoa. The mean rates of binding to the ZP of spermatozoa with normal morphology (44, 95% confidence limits 42-46, number bound/ZP/10(5)/ml inseminated) were much higher than for abnormal spermatozoa with small oval 6.5 (5.5-7.6), pyriform 5.9 (4.8-7.3), amorphous 1.0 (0.5-2.0) and tapering 2.5 (1.2-5.3) heads. The morphologically abnormal forms not found on the ZP were infrequent in the insemination medium (tail defects, large oval, round, pin and duplicate heads and cytoplasmic droplets) but upper 95% confidence limits for standardized binding ratios of less than 60% indicated that these were unlikely to bind to the zona with rates approaching those of normal spermatozoa (standardized binding ratio 180%). A large number of uniformly normal spermatozoa bound to the ZP when the percentage normal morphology in the insemination medium was greater than 40%. The proportions of abnormal spermatozoa in the insemination medium. Spermatozoon head dimensions were measured with a micrometer in samples from 14 patients. While there were no consistent changes in all samples, the means for head width and area were significantly larger and the ratio of the length to width was smaller for spermatozoa on the ZP than for those in the insemination medium. The head length and ratio of length to width of spermatozoa in samples with good morphology were significantly less than in samples with poor morphology. The percentage of spermatozoa with normal morphology, motility and the ratio of head length to width in the insemination medium were positively correlated with the percentage of spermatozoa with normal morphology bound to the ZP. Logistic regression analysis showed that the diagnosis of tubal infertility and the rate of binding of spermatozoa with normal morphology to the ZP were positively related to fertilization rates in vitro while the rate of binding of spermatozoa with pyriform heads was negatively related. In conclusion. human ZP are highly selective for spermatozoa with normal morphology. The frequency of binding of abnormal spermatozoa to the ZP was mainly dependent on semen quality.(ABSTRACT TRUNCATED AT 400 WORDS)

Female↗
PubMed1991

Horse and marmoset monkey sperm bind to the zona pellucida of salt-stored human oocytes.

The present study demonstrates that horse and marmoset monkey sperm can bind to the human zona of salt-stored oocytes that failed to fertilize in vitro. Marmoset monkey sperm are also able to penetrate the salt-stored human zona. In contrast, human sperm do not bind to the zona of either horse or marmoset monkey oocytes. These results suggest that human sperm binding to the zona pellucida is more strictly species-specific than it is for horse and marmoset monkey sperm. In contrast, horse and marmoset monkey sperm contain receptors recognized by the human zona.

Animals↗
PubMed1991

Variation of semen quality in normal men.

To examine the amount of variability in semen analysis results and whether there is any effect of season, 673 specimens provided by seven normal, healthy men (61-205 specimens/subject) over 72-324 weeks were assessed for sperm concentration, ejaculate volume, motility and motility index. Noticeable sample to sample variations were found. The largest proportion of the overall variance was due to within-subject differences, e.g., sperm concentration (54%), ejaculate volume (59%), percentage motility (96%) and motility index (74%). Although changes in semen-analysis results occurred over the year, no consistent trend was seen. No evidence was found to suggest that the differences were due to modifications of the methods employed by the laboratory, or to the change of season.

Adult↗
PubMed1991

Inhibition of human sperm-zona pellucida and sperm-oolemma binding by antisperm antibodies.

The results of this preliminary investigation suggest that antisperm antibodies interfere predominantly with sperm-zona pellucida binding. The observation of similar numbers of control (Ab-) and test (Ab+) sperm bound to the oolemma implies that the antibody-mediated inhibition of capacitation, acrosome reaction, or oolemma binding may not be major causes of failed fertilization with sperm autoimmunity. However, only seven patients were studied, and further investigation with larger numbers of subjects are required.

Autoantibodies↗
PubMed1990

Use of oocytes that failed to be fertilized in vitro to study human sperm-oocyte interactions: comparison of sperm-oolemma and sperm-zona pellucida binding, and relationship with results of IVF.

A test for human sperm binding to the oolemma was developed with oocytes that failed to be fertilized in vitro. The zonae pellucidae of the oocytes were removed under a dissecting microscope by brief exposure to dilute HCl (pH 2.5-3.0) in 0.9% NaCl. The zona-free oocytes (ZFOs) were incubated with a mixture of equal numbers of motile sperm from men to be tested and fertile donors. The sperm was differentially labelled with fluorescein or rhodamine and the results expressed as a ratio of the number of test to control sperm bound to several ZFOs in order to control for variability in the ability of the oolemma to bind sperm. The number of sperm bound to the oolemma increased with time and sperm concentration. The sperm-oolemma binding ratio determined for 32 patients undergoing in vitro fertilization (IVF) was significantly correlated with the sperm-zona pellucida (ZP) binding ratio but was not correlated with other sperm tests. The sperm-oolemma binding ratio was also related to the IVF rate, but this was not significant if the sperm-ZP binding ratio was included in the logistic regression model. Only four of the 32 patients had failure of fertilization in vitro. The human sperm-oolemma binding test may be useful for studying the interaction between gametes, but the test is unlikely to be as useful clinically as the sperm-ZP binding test for predicting fertilization in vitro.

Female↗
PubMed1990

Relationships between human sperm acrosin, acrosomes, morphology and fertilization in vitro.

Acrosin was measured in the semen used for sperm preparation for in-vitro fertilization (IVF) in 118 patients. Acrosin levels correlated with the proportion of spermatozoa with normal intact acrosomes determined with Pisum sativum agglutinin labelled with fluorescein. However, acrosin levels and the proportion of spermatozoa with normal intact acrosomes in semen were not significantly related to the fertilization rate in vitro. Only the percentage normal morphology and sperm concentration in the insemination medium were independently significantly related to the fertilization rate by logistic regression analysis. In patients with fewer than 30% of spermatozoa with normal morphology, although acrosin levels were not correlated with the fertilization rate, the proportion of spermatozoa with normal intact acrosomes in the insemination medium was the only significant factor in the logistic regression analysis. In conclusion, acrosin levels have no prognostic value for fertilization in vitro but the proportion of spermatozoa with normal intact acrosomes may be a useful clinical marker of fertilizing ability in men with poor sperm morphology.

Acrosin↗
PubMed1990

Human seminal clusterin (SP-40,40). Isolation and characterization.

Molecular cloning of the human complement inhibitor SP-40,40, has revealed strong homology to a major rat and ram Sertoli cell product, sulfated glycoprotein-2, known also as clusterin. This study reports the purification and characterization of human seminal clusterin. Two-dimensional gel electrophoresis revealed charge differences between clusterin purified from semen and the serum-derived material. Both preparations demonstrate comparable hemagglutination (clustering) activity and inhibition of C5b-6 initiated hemolysis. The average clusterin concentration in normal seminal plasma is considerably higher than that found in serum. Mean seminal plasma clusterin concentrations were significantly lower in azoospermia caused by obstruction or seminiferous tubule failure than with oligospermia or normospermia. Only men with vasal agenesis had undetectable seminal clusterin, suggesting that some of the seminal clusterin is produced by the seminal vesicles. Immunofluorescence of human spermatozoa revealed that clusterin was detected on 10% of spermatozoa, predominantly those that were immature or had abnormal morphology. A pilot study of 25 patients suggests that seminal clusterin concentration, together with sperm motility and morphology, is correlated with the fertilization rate in vitro. The function of seminal clusterin is unknown. Its extensive distribution in the male genital tract and its high concentration in seminal plasma suggests an important role in male fertility.

Animals↗
PubMed1990

Inducing the human acrosome reaction with a calcium ionophore A23187 decreases sperm-zona pellucida binding with oocytes that failed to fertilize in vitro.

The human acrosome reaction was induced with the calcium ionophore A23187 and the proportion of reacted spermatozoa was determined with fluorescein-labelled Pisum sativum agglutinin. Human oocytes that failed to fertilize in vitro were used to test binding of spermatozoa to the zona pellucida (ZP) and oolemma. Differential labelling of spermatozoa with fluorescein and rhodamine was used to control for variability in the oocytes. Spermatozoa labelled with one fluorochrome were treated with A23187 and mixed with equal numbers of motile untreated control spermatozoa labelled with the other fluorochrome. The mixture was incubated with zona-intact and zona-free oocytes for 4 h. The sperm-ZP binding ratio of test to control spermatozoa was significantly decreased with increasing proportions of acrosome reacted spermatozoa. In contrast, the sperm-oolemma binding ratio was significantly increased with A23187 treatment. This suggests that acrosome-reacted spermatozoa do not bind to the human ZP.

Acrosome↗
PubMed1989

Inadvertent pregnancies in oral contraceptive users.

Two hundred and nine inadvertent pregnancies in oral contraceptive users were studied to determine the associated factors. The percentage of Pill types also were compared with the market usage over the same period. We found that the classically-suggested cofactors, such as missed pills, late pills, drug ingestion, and gastrointestinal upsets were reported commonly. The triphasic Pills also were represented more frequently than would have been expected from their share of the market.

Adolescent↗
PubMed1989

Factors affecting fetal loss in induction of ovulation with gonadotropins: increased abortion rates related to hormonal profiles in conceptual cycles.

Thirty-six first-trimester abortions (9.7%), 16 second-trimester abortions (4.3%), 11 ectopic pregnancies (2.9%), and 10 stillbirths (2.7%) occurred in 373 conceptual cycles after gonadotropin induction of ovulation. Fetal wastage was higher in spontaneous pregnancies that occurred before therapy (54.3%, p less than 0.0001) and lower with subsequent spontaneous pregnancies (10.1%, p less than 0.05). Significant risk factors for overall fetal loss during induced ovulation were a continuous rise of estrogen excretion until ovulation (p less than 0.01) and previous abortion (p less than 0.05). For first-trimester abortion, the risk factor was continuous estrogen rise (p less than 0.01); for second-trimester abortion, the risk factors were a low luteal pregnanediol-to-estrogen excretion ratio (p less than 0.002), increased age at conception (p less than 0.02), and high baseline estrogen excretion (p less than 0.05). Multiple pregnancy was not significant. The continuous rising estrogen pattern may serve as a marker of abnormal oocyte maturation. We propose that future studies on infertility treatment should report on pregnancy outcome.

Abortion, Spontaneous↗
PubMed1989

A sperm-zona pellucida binding test and in vitro fertilization.

Sperm binding to the zona pellucida was studied in 106 in vitro fertilization (IVF) patients. Oocytes that failed to fertilize in vitro were inseminated with a mixture of equal numbers of test and fertile donor sperm differentially labeled with fluorescein or rhodamine to control for variability in the sperm-zona pellucida binding capacity of oocytes. The ratio of the number of test and control sperm bound to four to six zonae pellucidae was significantly correlated with sperm morphology, viability, motility, motility index, and normal intact acrosomes in semen. The sperm-zona pellucida binding ratio was the most significant factor related to IVF rates by logistic regression analysis. But the proportions of sperm with normal morphology and intact acrosomes in semen also were significant. In patients with less than 30% of sperm with normal morphology, there was a highly significant relationship between IVF rate and sperm-zona pellucida binding and a weaker relationship with sperm morphology. In conclusion, the sperm-zona pellucida binding ratio test is useful for predicting sperm fertilizing ability in vitro, particularly in men with poor sperm morphology.

Cell Survival↗