Home  About us  Contact
 

Sperm Defects (sperm + defect)

Distribution by Scientific Domains
Medical Sciences71%

Selected Abstracts

Sperm defects in mice lacking a functional Niemann,Pick C1 protein,

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006
Jun Fan
Abstract The Niemann,Pick C1 (NPC1) gene encodes for a multiple membrane spanning protein, which regulates the trafficking of low-density lipoprotein-mediated endocytosed cholesterol. Mutation of the human NPC1 gene causes Niemann,Pick type C (NPC) disease. The Npc1NIH mice, a model of human NPC disease, bear a spontaneous mutation of the Npc1 gene, and are infertile. In this study, we have performed sperm analysis to search for the cause of male infertility in the Npc1NIH mouse. The number of cauda sperms in Npc1,/, mice was decreased roughly three-and-half-fold of that in wild-type mice. The decreased sperm number in Npc1,/, mice is due, at least in part, to partial arrest of spermatogenesis in the testes, as revealed by histological analysis. Compared to wild-type sperm, Npc1,/, sperm displayed a high frequency of morphological abnormalities, including tailless heads and aberrant heads. In the in vitro fertilization (IVF) assay using cumulus-intact eggs, Npc1,/, sperm failed to produce two-cell embryos. In the IVF assay where zona-free eggs were used, Npc1,/, sperm bound normally but could not fuse with the egg. Further analysis indicated that Npc1,/, sperms are drastically impaired in the binding to the egg zona pellucida, only 14% of the level of wild-type sperm. Moreover, on Npc1,/, cauda sperm, one-third of the total cyritestin protein was not proteolytically processed, while fertilin , was processed normally. Taken together, these results demonstrate that there are multiple defects in sperms from mice lacking a functional NPC1 protein, and these observed sperm defects may result in sterility. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source]

Sperm morphology and aneuploidies: defects of supposed genetic origin

ANDROLOGIA, Issue 6 2006
G. Collodel
Summary As individuals with genetic sperm defects are intracytoplasmic sperm injection candidates, the study of the chromosomal constitution of their spermatozoa is of great interest. This study is a review of the current literature concerning fluorescence in situ hybridisation studies in spermatozoa with genetic sperm defect as ,round head', ,dysplasia of fibrous sheath' (DFS), ,primary ciliary dyskinesia' (PCD), the ,detached tail' and the ,absence of fibrous sheath'. Regarding sperm head defects, elevated XY disomy and diplodies were detected. Genetic defects affecting the sperm tail seemed to have a different correlation with chromosome meiotic segregation. Only chromosome 18, among the autosomes, was studied and the percentage of frequency of disomy was generally within the normal range. In the more frequently studied defect, DFS, the alterations in gonosome disomy and diploidy were recorded by different groups. Regarding PCD defects, elevated frequencies of disomy of sex chromosomes and diploidy were observed, whereas the absence of the fibrous sheath and the detached tail did not show any meiotic disturbance. The problem of genetic sperm defects should be seriously considered when these sperm are used for assisted reproduction, owing to the high risk of transmission of chromosomal imbalance and of mutations that could cause genetic sperm defects in offspring. [source]

Morphological sperm defects analyzed by light microscopy and transmission electron microscopy and their correlation with sperm motility

INTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2010
Vincenzo Visco
Objectives: To compare sperm defects as assessed by light microscopy (LM) and transmission electron microscopy (TEM), and to correlate them with sperm motility. Methods: A cohort of 40 male partners of infertile couples was selected. Group 1 (n = 31) included subjects with motility >5 and <50%, group 2 (n = 9) included those with motility <5% and the control group consisted of 10 normospermic subjects. Semen analysis of morphological parameters was carried out by LM and TEM. Results: A linear correlation between LM and TEM regarding head defects and excess residual cytoplasm (r = 0.87 and 0.90) was found, whereas there was a poor correlation between tail and midpiece anomalies (r = 0.46 and 0.21). No significant variations were detected by LM and TEM regarding sperm head defects and excess residual cytoplasm, whereas TEM showed a significantly greater percentage of tail and midpiece alterations compared with LM in groups 1 and 2, as well as controls (P < 0.05). The microtubular pattern ,<9 + 2' represented the most frequent axonemal morphological alteration. Conclusions: TEM might represent an additional diagnostic tool in the presence of severe sperm hypomotility or absence of motility. [source]

Sperm defects in mice lacking a functional Niemann,Pick C1 protein,

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006
Jun Fan
Abstract The Niemann,Pick C1 (NPC1) gene encodes for a multiple membrane spanning protein, which regulates the trafficking of low-density lipoprotein-mediated endocytosed cholesterol. Mutation of the human NPC1 gene causes Niemann,Pick type C (NPC) disease. The Npc1NIH mice, a model of human NPC disease, bear a spontaneous mutation of the Npc1 gene, and are infertile. In this study, we have performed sperm analysis to search for the cause of male infertility in the Npc1NIH mouse. The number of cauda sperms in Npc1,/, mice was decreased roughly three-and-half-fold of that in wild-type mice. The decreased sperm number in Npc1,/, mice is due, at least in part, to partial arrest of spermatogenesis in the testes, as revealed by histological analysis. Compared to wild-type sperm, Npc1,/, sperm displayed a high frequency of morphological abnormalities, including tailless heads and aberrant heads. In the in vitro fertilization (IVF) assay using cumulus-intact eggs, Npc1,/, sperm failed to produce two-cell embryos. In the IVF assay where zona-free eggs were used, Npc1,/, sperm bound normally but could not fuse with the egg. Further analysis indicated that Npc1,/, sperms are drastically impaired in the binding to the egg zona pellucida, only 14% of the level of wild-type sperm. Moreover, on Npc1,/, cauda sperm, one-third of the total cyritestin protein was not proteolytically processed, while fertilin , was processed normally. Taken together, these results demonstrate that there are multiple defects in sperms from mice lacking a functional NPC1 protein, and these observed sperm defects may result in sterility. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source]

Immunoexpression of Aromatase in Immature and Adult Males of the European Bison (Bison bonasus, Linnaeus 1758)

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2010
I Kopera
Contents Based on recent literature dealing with the role of oestrogens in the male gonad, attempts were undertaken to reveal the site of aromatization within the testis of the European bison (Bison bonasus). Testes were collected from culled animals living in free-ranging populations in Bialowieza Forest, Poland (nine males aged 8 months to 10 years). Moreover, to check for any alterations in the expression of testicular aromatase between American bison (Bison bison) and European bison, testes from one adult 10-year-old individual were also chosen for this study. For immunohistochemistry, 4% formaldehyde fixative was used. Both qualitative and quantitative evaluations of immunohistochemical staining were performed. Leydig cells, Sertoli cells and germ cells exhibited a positive immunoreaction for aromatase in testes of immature and sexually mature bison. A marked increase in aromatase expression was observed in three adult European individuals with impaired spermatogenesis. Consistent with recent data and those of our own, it might be suggested that the strong expression of aromatase negatively affects spermatogenic function in bison testes and may serve as a possible explanation of specific sperm defects observed in European bison bulls. On the contrary, one cannot exclude that differences in the aromatase immunoexpression levels are attributed to the homozygosity, the cause of frequent disease in European bison. [source]

Sperm morphology and aneuploidies: defects of supposed genetic origin

ANDROLOGIA, Issue 6 2006
G. Collodel
Summary As individuals with genetic sperm defects are intracytoplasmic sperm injection candidates, the study of the chromosomal constitution of their spermatozoa is of great interest. This study is a review of the current literature concerning fluorescence in situ hybridisation studies in spermatozoa with genetic sperm defect as ,round head', ,dysplasia of fibrous sheath' (DFS), ,primary ciliary dyskinesia' (PCD), the ,detached tail' and the ,absence of fibrous sheath'. Regarding sperm head defects, elevated XY disomy and diplodies were detected. Genetic defects affecting the sperm tail seemed to have a different correlation with chromosome meiotic segregation. Only chromosome 18, among the autosomes, was studied and the percentage of frequency of disomy was generally within the normal range. In the more frequently studied defect, DFS, the alterations in gonosome disomy and diploidy were recorded by different groups. Regarding PCD defects, elevated frequencies of disomy of sex chromosomes and diploidy were observed, whereas the absence of the fibrous sheath and the detached tail did not show any meiotic disturbance. The problem of genetic sperm defects should be seriously considered when these sperm are used for assisted reproduction, owing to the high risk of transmission of chromosomal imbalance and of mutations that could cause genetic sperm defects in offspring. [source]