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Biomedical subjects

C H Muller

Publications and source records attributed to C H Muller.

At least 19 recordsLinked to original sources
PubMed1992

Purification and characterization of a human follicular fluid lipid transfer protein that stimulates human sperm capacitation.

Identification of the mechanisms responsible for sperm capacitation has been an active area of research for nearly four decades. Changes in the lipid composition of the sperm membrane is one of the biochemical events that occurs during sperm capacitation. We have been studying physiological effectors of some of these changes and have identified lipid transfer activity in fractions of human follicular fluid that stimulates sperm penetration of zona-free hamster oocytes. We report here the purification of a lipid transfer protein by sequential chromatography from human follicular fluid. This protein was purified greater than 20,000-fold for lipid transfer activity and greater than 28,000-fold for sperm penetration-inducing activity. This 64,000 molecular weight protein has a pI of approximately 5.0 and shares physicochemical characteristics with the plasma lipid transfer protein, LTP-I. Antibodies to LTP-I also recognize this protein and depletion of LTP-I from human follicular fluid by immunoaffinity chromatography renders the follicular fluid incapable of stimulating sperm penetration. We conclude that purified LTP-I is able to stimulate human sperm capacitation and that LTP-I is a molecule responsible for this stimulation in follicular fluid.

Antibodies, Monoclonal↗
PubMed1990

Relationship of bacteriologic characteristics to semen indices in men attending an infertility clinic.

Bacteria can be isolated from most seminal fluid samples, but the significance of these microorganisms is uncertain because most men lack symptoms associated with bacterial infection of the reproductive tract. We obtained semen samples from 37 men attending a Special Infertility Clinic and assessed the relationship between seminal fluid microorganisms and seminal fluid analysis including sperm motility, morphology, and concentration; the numbers of polymorphonuclear leukocytes and other white blood cells; and the hamster zona-free oocyte sperm penetration assay. Aerobic and/or anaerobic bacteria were recovered from 36 of the 37 samples. One hundred eighty-eight isolates (113 aerobes, 74 anaerobes, and one yeast) were recovered, with a mean of 5.2 isolates per semen specimen. The microorganisms recovered from the samples included: coagulase-negative staphylococci (89%), viridans streptococci (65%), diphtheroids (86%), Peptostreptococcus sp (62%), Bacteroides sp (27%), Gardnerella vaginalis (19%), Lactobacillus sp (16%), Actinomyces sp (16%), Enterococcus (11%), and Veillonella (11%). Other microorganisms including group B streptococcus, Hemophilus, Escherichia coli, Mobiluncus, and Clostridium were each recovered from fewer than 10% of the specimens. When the microbiology of seminal fluid specimens with or without polymorphonuclear leukocytes was compared, the presence of polymorphonuclear leukocytes in the semen was not associated with the isolation of staphylococci (33 versus 25%), viridans streptococci (33 versus 28%), Bacteroides sp (17 versus 37%), or Peptostreptococcus (31 versus 33%) (P greater than .05 for each comparison). The proportion of semen samples yielding bacterial isolates was similar after categorization by normal motility (more than 60%), pyospermia (six or more leukocytes per 100 sperm), sperm concentration, morphology, and a normal sperm penetration assay (11% or more).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The clinical relevance of sex selection techniques.

Clinical and laboratory attempts to alter the sex ratio require more complete and thorough study. Improved identification of Y-bearing sperm through chromosome evaluation rather than by F-body identification is critical to provide a more precise definition. The tentative conclusions stated below are based on an assessment of literature from which it is generally difficult to draw conclusions: 1. The timing of intercourse in relation to ovulation and subsequent fertilization appears to influence the sex ratio. More females are conceived when coitus occurs relatively close to ovulation, and more males are conceived when the sperm or egg is in the reproductive tract for a relatively longer time before conception. The influence of coital timing on the sex ratio is overall quite subtle and is not a practical method to alter the sex ratio for individual couples. 2. The use of ovulation-inducing medications slightly favors female offspring. A decrease in sex ratio of 5% to 10% has been shown in multiple studies. 3. Artificial insemination with fresh donor or homologous spermatozoa results in more male births with a reported 7% to 10% increase in the sex ratio. It appears that ovulation induction combined with artificial insemination cancels the respective influences of each on the sex ratio. 4. Sperm separation techniques using albumin (for selection of Y-bearing sperm) or Sephadex column filtration (for selection of X-bearing sperm) are the only techniques that have been reported to alter the sex ratio to a degree that is clinically relevant. Although clinical birth data are just beginning to accumulate, these methods appear to have a 70% to 80% success for selection of assumed Y-bearing sperm and a 75% to 80% success for selection of assumed X-bearing sperm. The validity of these results will remain questionable until fully detailed accounts are published and successfully repeated. Free-flow electrophoresis appears to achieve significant separation; however, the depressed postprocedure spermatozoa motility presently limits the usefulness of this procedure. 5. There is a potential to combine clinical and laboratory methods to maximize the efficiency of sex selection for interested couples. Modern methods to identify ovulation (e.g., urinary LH kits, ultrasonography) may help the timing of coitus for sex selection. Clomiphene citrate may enhance female sex preselection when Sephadex column filtration is also employed. 6. The priority of sex preselection in terms of medical, social, and demographic consideration remains to be determined. The avoidance of sex-linked genetic disorders is a reasonable and desirable goal.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Separation↗
PubMed1988

Identification of a protein in the fibrous sheath of the sperm flagellum.

The fibrous sheath is a unique cytoskeletal component in the principal-piece segment of the mammalian sperm flagellum. Monoclonal antibody ATC was shown by indirect immunofluorescence (IIF) to bind to the principal piece of the flagellum of permeabilized mouse, rat, and hamster sperm, but not to that region of guinea pig, rabbit, or human sperm. IIF on isolated fibrous sheaths confirmed that the antigen was present in the fibrous sheath of mouse, rat, and hamster sperm. On Western blots of mouse spermatozoa, ATC identified a relatively insoluble major antigen with an apparent molecular weight of 67,000 (Mr 67,000). Hamster sperm fibrous sheaths contain an antigen of Mr 66,000, while rat sperm fibrous sheaths contain an antigen of Mr 65,500. The antigen was first detected in late spermatids, as determined by immunohistochemical procedures on sections of mouse, rat, and hamster testis. The antigen was not detected on Western blots of mouse brain, kidney, liver, or thymus. These results indicate that ATC recognizes a protein integral to the fibrous sheath of the principal piece of sperm detected by immunohistochemistry late in spermiogenesis that is probably restricted to the male germ cell line.

Animals↗
PubMed1988

Sperm penetration assay and subsequent pregnancy: a prospective study of 74 infertile men.

Seventy-four men of infertile couples, for whom a female infertility factor had been excluded, were followed for up to three years after semen analyses that included the sperm penetration assay, an in vitro test of sperm function. At 156 weeks after a normal sperm penetration assay, the cumulative pregnancy rate was 68%, versus only 27% when an abnormal assay was noted. Cumulative pregnancy percents at one year varied significantly (P less than .02) according to the magnitude of the assay result (0%, 1-10%, 11-15%, 16% or greater). However, differences between 0% versus 1-10%, and 11-15% versus 16% or greater, were not statistically significant. Only one of 14 men effected conception after an assay result of 0%. These findings were little altered when analysis of the sperm penetration assay was restricted to men with normal sperm concentration (20 X 10(6) sperm mL-1 or greater) and motility (60% or greater). The presence of pyospermia (six or more white blood cells per 100 spermatozoa) was associated with continued infertility, but neither abnormal sperm concentration nor motility were associated significantly with lower cumulative pregnancy percents. When performed for infertile men according to standard protocol, the sperm penetration assay enhances prediction of future pregnancy.

Adult↗
PubMed1987

The use of sperm penetration assay in evaluation of men with varicocele.

In order to study the ability of the sperm penetration assay (SPA) to correctly classify the fertility status of men, we prospectively examined the results of the SPA performed on the semen of three groups of men of known fertility status. The groups included 67 normal men without varicoceles whose wives were pregnant (VARN), 51 men with a palpable varicocele whose wives were pregnant (VARF), and 30 infertile men with varicoceles (VARI). Two SPAs were done on each subject. Ninety-seven percent of the VARIs showed less than 15% penetration on a single test, and 91% showed less than 15% on both tests. On a single test 61% of the VARNs and 68% of the VARFs were less than 15%. If 0 penetration were used as the criteria of infertility, then 40% of the VARIs, 27% of the VARFs, and 12% of the VARNs would be classified as being infertile. These data suggest that the SPA cannot independently define male fertility status and should be used in conjunction with the standard semen analysis and clinical evaluation of the couple to assess male fertility potential.

Female↗
PubMed1987

Human sperm penetration assay as an indicator of sperm function in human in vitro fertilization.

Performance of spermatozoa in a hamster oocyte/human sperm penetration assay (SPA) was correlated with the results of in vitro fertilization (IVF). Forty-two patients underwent 50 IVF cycles. SPA scores were obtained before IVF cycles (screening SPA, n = 30) and, where practical, on the semen sample used for IVF (IVF SPA, n = 26). Screening SPA score did not correlate to IVF result, fertilization and cleavage rates were similar between normal (n = 17) and low (n = 13) SPA groups, pregnancy rates were 35 and 46%, respectively. In addition, SPA score at the time of IVF did not correlate with IVF result. Pregnancy rates were 33% for the normal group (n = 16) and 30% for the low SPA group (n = 10). Overall, the low SPA group (n = 16) exhibited a 78% fertilization rate and a 38% pregnancy rate, which was not different from the normal SPA group: 76 and 29%, respectively. The results of this study indicate that SPA score is a poor indicator of sperm function in IVF.

Adult↗
PubMed1986

Operative recovery of vasal sperm from anejaculatory men: preliminary report.

Sperm showing good motility and function, as demonstrated by the in vitro sperm penetration assay using hamster ova, were collected from the vas deferens of 3 men with ejaculatory failure. The collection procedure may be repeated over multiple ovulatory cycles. The sperm may be used to attempt artificial insemination or in vitro fertilization.

Adult↗
PubMed1985

Immunodissection of sperm surface modifications during epididymal maturation.

Mammalian spermatozoa undergo changes in morphology, composition, and function during transit through the epididymis. These changes correlate with acquisition by sperm of the ability to fertilize ova. It has been found that sperm from the cauda epididymidis, but not those from the caput epididymidis, are able to bind to the zona pellucida. This would imply a modification in sperm surface characteristics. Biochemical and immunological studies have demonstrated changes in sperm surface composition during epididymal maturation. These changes involve addition of epididymal secretory products to the sperm surface, loss or alteration of existing sperm surface molecules, and possibly the unmasking of preexisting molecules or epitopes. Several laboratories have studied the epididymal secretory proteins in the rat, but a consensus has not been reached on the identification, characterization, source, and sperm surface association of these proteins. Monoclonal antibodies are beginning to be used to characterize sperm surface components and sperm maturation antigens. They are proving to be valuable tools for the dissection of epididymal maturation when used in conjunction with biochemical and physiological approaches.

Animals↗
PubMed1985

Relationship of hamster ovum sperm penetration assay to seminal fluid analyses in the evaluation of infertile couples.

The males of 279 infertile couples were evaluated with hamster ovum sperm penetration assay (SPA) and seminal fluid analysis. The mean SPA score for the total population was 23.0% penetration with a range of 0-97%. Twenty five percent of the patients demonstrated scores within the abnormal range (0-10%), and 15% were in the "equivocal" range (11-14%). Comparing each individual with the total population using linear regression analysis, it was noted that sperm concentration, percent motility, and percent oval forms varied directly with the SPA, and the slopes of the relationships are positive and statistically significant (p less than 0.0001, 0.002, and 0.0001, respectively). The relationship between SPA and volume is not statistically significant (p greater than or equal to 0.354). To determine whether the SPA could be utilized to establish appropriate normal parameters for various components of SFA, these were analyzed in 169 men who had SPAs of greater than or equal to 15%. Although most SFA values fell within the normal range for this group, there were several exceptions, particularly with respect to percent motility and the presence of leukocytes in the semen. Comparing the percentage of males with abnormal SPA in groups of couples with or without a demonstrable abnormality affecting fertility in the wife, no statistically significant differences could be found. The value of the SPA and SFA in investigating males of infertile couples is discussed.

Adult↗
PubMed1982

Epididymal secretion of a mouse sperm surface component recognized by a monoclonal antibody.

We have generated a monoclonal antibody directed against an antigenic determinant appearing on the surface of mouse sperm tails during passage through the epididymis (a determinant that we now term sperm maturation antigen number four [SMA 4]). The present study demonstrates that sperm retained in the ductuli efferentes following ligation do not acquire the antigen, suggesting that its appearance is not due to changes intrinsic to the sperm, but that the epididymal environment is required. To examine the role of the epididymis in the appearance of this antigen, sections of unfixed frozen or fixed, paraffin embedded tissue from different regions of the male reproductive tract have been studied by indirect immunofluorescence. Results indicate that the antigen is a secretory product of the epididymal epithelium, produced in a short segment of the distal caput epididymidis. Ligation experiments show that absence of sperm or testicular fluid from the epididymis does not affect production of this antigen. Examination of prepubertal mice indicates that antigen production is age dependent, production beginning in the epididymis in mice between 2 and 4 weeks of age. Indirect immunofluorescence analysis of sections of a variety of tissues and organs shows that the antigen is restricted to sperm and to epithelial cells of the male reproductive tract. Finally, experiments comparing the antibody-induced agglutinability of sperm from the caput epididymidis to that of sperm from the cauda epididymidis gives further evidence that the antigen resides on the sperm surface.U

Agglutination↗