Meiotic chromosome abnormalities in fertile men: are they increasing?
Summary of "Meiotic chromosome abnormalities in fertile men: are they increasing?"
To determine the basal frequencies of meiotic chromosome abnormalities in fertile men.
Research university laboratory and clinical andrology service. PATIENT(S): Seventeen fertile donors undergoing vasectomy. INTERVENTION(S): Analysis of testicular biopsies. MAIN OUTCOME MEASURE(S): Meiotic chromosome abnormalities in metaphase I spermatocytes. RESULT(S): A total of 1,407 spermatocytes I was analyzed. The main meiotic abnormality was absence or low chiasma number of individual bivalents (23.4%), followed by structural (3.3%) and numerical (0.7%) abnormalities. Sex chromosomes and G-group chromosomes were the most commonly found as univalents at metaphase I. Statistically significant heterogeneity was found for meiotic abnormalities among fertile men, caused by interindividual variation in the level of dissociated sex chromosomes (ranging from 3.2% to 43.7%). The mean total percentage of meiotic abnormalities in spermatocytes I from fertile men was 27.4%, 1.7 times higher than those described a few decades ago in fertile and even in infertile men. CONCLUSION(S): Fertile men are a heterogeneous group for meiotic errors, with individuals showing percentages of meiotic abnormalities as high as 50%. From these findings, caution is recommended when using meiotic studies to diagnose and provide genetic counselling to patients consulting for infertility.
Departament de Biologia Cel.lular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.
This article was published in the following journal.
Name: Fertility and sterility
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20674909
- DOI: http://dx.doi.org/10.1016/j.fertnstert.2010.06.042
Medical and Biotech [MESH] Definitions
Protein kinase that drives both the mitotic and meiotic cycles in all eukaryotic organisms. In meiosis it induces immature oocytes to undergo meiotic maturation. In mitosis it has a role in the G2/M phase transition. Once activated by CYCLINS; MPF directly phosphorylates some of the proteins involved in nuclear envelope breakdown, chromosome condensation, spindle assembly, and the degradation of cyclins. The catalytic subunit of MPF is PROTEIN P34CDC2.
Sister Chromatid Exchange
An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.
The period in the MENSTRUAL CYCLE that is optimal for FERTILIZATION of the OVUM and yielding PREGNANCY. The duration of fertile period depends on the life span of male GAMETES within the female reproductive tract and the time of OVULATION. It usually begins a few days before ovulation and ends on the day of ovulation.
Meiotic Prophase I
The prophase of the first division of MEIOSIS (in which homologous CHROMOSOME SEGREGATION occurs). It is divided into five stages: leptonema, zygonema, PACHYNEMA, diplonema, and diakinesis.
Natural Family Planning Methods
A class of natural contraceptive methods in which SEXUAL ABSTINENCE is practiced a few days before and after the estimated day of ovulation, during the fertile phase. Methods for determining the fertile period or OVULATION DETECTION are based on various physiological indicators, such as circulating hormones, changes in cervical mucus (CERVIX MUCUS), and the basal body temperature.
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