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Query: UNIPROT:P06889 (Mol)
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Microdeletions linked to deletion intervals 5 and 6 of the Y chromosome have been associated with male factor infertility. Members from at least two gene families lie in the region containing azoospermia factor (AZF), namely YRRM and DAZ. With the advent of intracytoplasmic sperm injection (ICSI), it is possible for men with severe male factor infertility to produce a child. The genetic consequences of such a procedure have been questioned. This report describes the first study of a population (32 couples) of infertile fathers and their sons born after ICSI. The objectives were firstly to determine the incidence and map location of Y chromosome microdeletions and to compare the frequencies with other population studies involving severe male factor infertility, and secondly to formulate a working hypothesis concerning developmental aetiology of Y chromosome microdeletions. The incidence of microdeletions in the ICSI population was shown to be 9.4% (within the range 9-18% reported for populations of severe male factor infertility patients). Microdeletions in two out of three affected father/son pairs mapped in the region between AZFb and AZFc and the third involved a large microdeletion in AZFb and AZFc. Of three affected father/son pairs, microdeletions were detected in the blood of one infertile propositus father and three babies. Assuming that the gonomes of the ICSI-derived babies are direct reflections of those of their fathers germ lines, it is possible that two of three infertile fathers were mosaic for intact Y and microdeleted Y chromosomes. In such cases, the developmental aetiology of the microdeletion may be due to a de-novo microdeletion arising as a post-zygotic mitotic error in the infertile propositus father, thus producing a mosaic individual who may or may not transmit the deletion to his ICSI-derived sons depending on the extent of primordial germ cell mosaicism. In one of three affected fathers, the microdeletion detected in his blood was also detected in his ICSI-derived son. In this case the de-novo event giving rise to the microdeletion may have occurred due to a post- (or pre-) meiotic error in the germ line of this father's normally fertile father (i.e. the ICSI-derived baby's grandfather).
Mol Hum Reprod 1996 Dec
PMID:The incidence and possible relevance of Y-linked microdeletions in babies born after intracytoplasmic sperm injection and their infertile fathers. 923 38

Successful intracytoplasmic sperm injection (ICSI) is dependent upon the competence of the oocyte to respond to the injection of a spermatozoon in the presence of calcium. This study determined if oocytes that failed to become fertilized (absence of any pronuclei) failed to undergo cytoplasmic activation, as ascertained by an electrophoretic shift in the zona pellucida (zona) protein, huZP2. Of 48 zonae individually analysed, 58% did not have a detectable huZP2 shift. Three patterns were observed. In seven patients, none of the unfertilized oocyte huZP2 shifted (16 out of 48); in two, all zonae exhibited a huZP2 shift (five out of 48); in eight, there was a mixture of shifted and unshifted (27 out of 48) in each case. There was no clear relationship between the presence of the huZP2 shift and maternal age, pregnancy outcome, male-factor infertility, or fertilization rate. However, in six couples diagnosed as having no detectable male-factor infertility, 73% (11 out of 15) of the zonae had unshifted huZP2, suggesting that an oocyte defect is involved in some cases of failed fertilization after ICSI. One likely cause for the absence of the huZP2 shift is a failure of cytoplasmic activation. Since oocytes were injected at metaphase II, we hypothesize that some oocytes that failed to fertilize have completed nuclear (meiotic) without cytoplasmic maturation.
Mol Hum Reprod 1996 Dec
PMID:Biochemical study of individual zonae from human oocytes that failed to undergo fertilization in intracytoplasmic sperm injection. 923 40

Women with recurrent abortion, primary unexplained infertility, and gestational trophoblastic neoplasia (GTN) manifest disordered human chorionic gonadotrophin (HCG) secretion. Mutations in the HCG beta/luteinizing hormone (LH) beta gene complex could cause aberrant HCG production in these disorders. The purpose of this study was to determine whether HCG beta gene deletions occur in women with recurrent abortion or primary unexplained infertility, and whether HCG beta gene duplications are present in women with GTN. DNA was extracted from 10 patients with unexplained recurrent abortion, 10 patients with unexplained primary infertility, 12 patients with GTN, three partners of women with GTN, and 30 controls. Southern blots were constructed and hybridized with DNA probes for HCG beta-5 and the LH beta gene. No gene deletions were identified in patients with recurrent abortion or primary unexplained infertility. Likewise, no gene duplications were identified in women with GTN. A previously described Mbol restriction fragment length polymorphism (RFLP) was identified in both patients and controls. A new Pstl RFLP was also characterized, but was present in patients and controls. Deletion/duplication mutations in the HCG beta/LH beta gene complex do not appear to be common causes of aberrant HCG production in humans with these disorders.
Mol Hum Reprod 1997 Apr
PMID:Human chorionic gonadotrophin-beta gene sequences in women with disorders of HCG production. 923 59

Because of its distinctive ability to act as a mitogen, a mitogen and a morphogen, hepatocyte growth factor/scatter factor (HGF/SF) has all the characteristics of a molecule able to function in regulatory networks of motility, such as the spermatogenic epithelium, and this through binding of its receptor p190MET (C-MET). In this study we report the expression of C-MET in the human seminiferous epithelium and on spermatozoa from men being treated for infertility and sperm donors. The presence of C-MET was demonstrated by immunochemistry on the cell membrane of spermatogonia, spermatocytes, spermatids and on spermatozoa, whereas Sertoli cells and Leydig cells did not show expression. Comparison of C-MET expression on spermatozoa of the 90% Percoll layer of subfertile patients and donors revealed clearly two distinct groups (unpaired t-test, P < 0.001), whereas comparison of C-MET expression on spermatozoa in the 47% Percoll layer was not significantly different between patients and donors. In addition, there was a significant inverse correlation between sperm concentration and the C-MET expression of spermatozoa in the 90% Percoll layer (r = -0.80, 95% confidence interval, -0.92 to -0.55; P < 0.0001), but not with the C-MET expression of spermatozoa in the 47% Percoll layer. In conclusion, the presence of C-MET was demonstrated in the seminiferous epithelium and on mature and immature spermatozoa, indicating a role for this growth factor receptor in the differentiation and/or migration that occurs during human spermatogenesis.
Mol Hum Reprod 1996 Jan
PMID:The receptor encoded by the human C-MET oncogene is expressed in testicular tissue and on human spermatozoa. 923 50

This study aimed to investigate the association between anomalies in sperm chromatin packaging, morphology and fertilization in patients undergoing routine in-vitro fertilization (IVF) or subzonal insemination (SUZI). Sperm chromatin packaging was assessed using chromomycin A3 (CMA3), a fluorochrome specific for guanine-cytosine rich sequences of DNA. One hundred to 150 sperm cells were assessed in 55 patients to compare sperm chromatin packaging and morphology to fertilization after IVF or SUZI. When the morphology and CMA3 fluorescence of individual spermatozoa was assessed, > 75% of the macrocephalic sperm fluoresced in all patients. In contrast, a mean of 37% of the spermatozoa with normal morphology fluoresced in IVF patients compared with 58% of the normal spermatozoa in male factor patients treated by SUZI. SUZI patients displaying a high fluorescence (> 70%) in their spermatozoa also had a significantly lower fertilization rate. Lower packaging quality in morphologically normal spermatozoa may represent a major limiting factor in the fertilizing ability of male factor patients. This study confirms that a high percentage of CMA3 positivity is present in certain forms of male factor infertility and that such a test may be used to distinguish separate populations in morphologically normal spermatozoa.
Mol Hum Reprod 1996 Mar
PMID:Chromatin packaging and morphology in ejaculated human spermatozoa: evidence of hidden anomalies in normal spermatozoa. 923 72

The introduction of the polymerase chain reaction (PCR) as a technique to selectively amplify and identify specific DNA and RNA sequences has revolutionized the field of molecular medicine. Application of these newly developed molecular techniques to the field of male infertility has made the delineation of subtle causes of infertility-an inapparent genital tract infection, immune system activation within the genital tract, mutations in sperm mitochondrial or chromosomal DNA, alterations in sperm components involved in receptor-ligand interactions, and production of sperm autoantibodies-all increasingly amenable to clinical analysis. Continued investigations at the molecular level of the causes of male infertility will also lead to novel treatment regimens as well as development of new methods of fertility regulation.
Mol Hum Reprod 1996 Mar
PMID:Molecular approaches to the diagnosis of male infertility. 923 79

The chain-breaking antioxidant alpha-tocopherol has not been reported to be present in mammalian spermatozoa, unlike other cell types where it contributes to cell integrity and function. Semen samples obtained from 36 male partners of infertile couples during infertility investigations were analysed for alpha-tocopherol content of seminal plasma and spermatozoa, and the superoxide dismutase and glutathione peroxidase activities of spermatozoa were determined concomitantly with routine semen analysis. A wide range of alpha-tocopherol concentrations was detected in human spermatozoa (85 +/- 51 ng/10(8) spermatozoa, range 10-245). The concentration of alpha-tocopherol in spermatozoa was not found to be significantly related to the concentration or the total amount of alpha-tocopherol in seminal plasma. The percentage of motile spermatozoa was significantly related to sperm alpha-tocopherol content (r = 0.84, P < 0.001). alpha-tocopherol concentration and superoxide dismutase and glutathione peroxidase activities of spermatozoa were significantly elevated when the semen samples contained < 10(6) leukocytes/ml (mean +/- SD, 94 +/- 53 compared with 54 +/- 29 ng/10(8) spermatozoa, P < 0.02, 1.15 +/- 0.41 compared with 0.77 +/- 0.30 IU/10(8) spermatozoa, P < 0.02 and 60 +/- 26 compared with 30 +/- 14 spermatozoa mlU/10(8) spermatozoa, P < 0.005 respectively). From these results, it is suggested that alpha-tocopherol might play a role in association with antioxidant enzymes, for preserving the functional competence of spermatozoa subjected to an oxidative attack.
Mol Hum Reprod 1996 Oct
PMID:alpha-Tocopherol in human spermatozoa and seminal plasma: relationships with motility, antioxidant enzymes and leukocytes. 923 91

Overall, approximately 11% of men attending infertility clinics suffer unexplained oligo- or azoospermia. Cytogenetic observations of loss of the distal portion of the Y chromosome long arm (Yq) were found to be associated with disrupted spermatogenesis. The existence of a gene locus involved in the regulation of spermatogenesis, the azoospermia factor (AZF), was thus postulated. It is suggested that microdeletions, or mutations, at the AZF locus could result in impaired spermatogenesis in chromosomally normal men. In order to test this hypothesis we have carried out Y chromosome genetic screening of 100 oligo- or azoospermic 46XY patients. We have also assessed phenotype/genotype relationships in those patients whose infertility has an underlying genetic aetiology. Patients were screened by polymerase chain reaction (PCR) with a set of Y chromosome-specific sequence tagged sites (STS) for submicroscopic deletions of their Y chromosome. Our results show that as many as 8% of cases of unexplained male infertility may have an underlying genetic aetiology related to microdeletions in two specific regions of the Y chromosome. Positive results from such a screen will be important when deciding the suitability of a patient for assisted conception schemes such as intracytoplasmic sperm injection.
Mol Hum Reprod 1996 Oct
PMID:Polymerase chain reaction screening for Y chromosome microdeletions: a first step towards the diagnosis of genetically-determined spermatogenic failure in men. 923 96

The purpose of the study was to analyse the frequency of sex-chromosome numerical abnormalities in human spermatozoa of infertile men by using a standardized experimental protocol of double target in-situ hybridization (ISH). The experiments were performed on decondensed sperm heads from 15 infertile patients (six cases of unexplained infertility and nine cases of severe oligoasthenoteratozoospermia). Three men of proven fertility were used as controls. The probes employed recognized the centromeric regions of human X chromosome and the long arm of the Y chromosome. In a smaller number of cases, additional experiments of double ISH were performed using centromeric probes for chromosomes 1 and 17. Signal detection was based on protocols of enzymatic cytochemical reactions. A total of 24,508, 24,679 and 42,285 cells were scored in the control, unexplained infertility and severe male factor groups of patients respectively. In all the patients in the ISH efficiency result was approximately 98%. In controls, unexplained infertility and severe male factor patients, the frequency of morphologically normal sperm cells carrying an abnormal chromosome constitution (XX or YY or XY or > 2 sex chromosomes signals) was 0.86, 0.75 and 1.35% respectively. The value of this last group of patients (severe male factor) was significantly higher than in the other two groups of patients (P < 0.008). The same findings were made using the autosomic probes. Our preliminary data support the possibility of an increased risk from paternal origin sex chromosome aneuploidies in children born after intracytoplasmic sperm injection (ICSI). Further investigations of the cytogenetic constitution of spermatozoa from severe male factor patients is warranted.
Mol Hum Reprod 1997 May
PMID:Comparison of gonosomal aneuploidy in spermatozoa of normal fertile men and those with severe male factor detected by in-situ hybridization. 923 28

In sperm cells, the majority of coenzyme Q10 (CoQ10) an energy promoting agent and antioxidant, is concentrated in the mitochondria of the midpiece, so that the energy for movement and all other energy-dependent processes in the sperm cell also depend on the availability of CoQ10. The reduced form of CoQ10-ubiquinol also acts as an antioxidant, preventing lipid peroxidation in sperm membranes. The objective of the study was to evaluate the effect of CoQ10 on sperm motility in vitro, after incubation with 38 samples of asthenospermic and normal motility sperm, and to evaluate the effect of CoQ10 administration in vivo in 17 patients with low fertilization rates after in vitro fertilization with intracytoplasmic sperm injection (ICSI) for male factor infertility. All 38 sperm samples from patients registered in our infertility clinic had normal concentrations and morphology. Of these, 16 patients had normal motility (mean 47.5%) and 22 patients were asthenospermic (mean motility 19.1%). Sperm samples were divided into four equal parts and incubated for 24 h in: HAM's medium alone, in HAM's medium with 1% DMSO and HAM's with 5 microM or 50 microM CoQ10. While no significant change in motility after incubation was observed in the samples with initial normal motility, a significant increase in motility was observed in the 50 microM CoQ10 subgroup of sperm from asthenospermic men, with a motility rate of 35.7 +/- 19.5%, as compared to 19.1 +/- 9.3% in the controls (P < 0.05). The 17 patients with low fertilization rates after ICSI were treated with oral CoQ10, 60 mg/day, for a mean of 103 days before the next ICSI treatment. No significant change was noted in most sperm parameters, but a significant improvement was noted in fertilization rates, from a mean of 10.3 +/- 10.5% in their previous cycles, to 26.3 +/- 22.8% after CoQ10 (P < 0.05). In conclusion, the administration of CoQ10 may result in improvement in sperm functions in selective patients. Further investigation into the mechanisms related to these effects is needed.
Mol Aspects Med 1997
PMID:The effect of coenzyme Q10 on sperm motility and function. 926 24


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