Methods of sperm DNA extraction for genetic and epigenetic studies.

High quality DNA extractions developed for mammalian somatic cells are ineffective for sperm, due mainly to the high degree of nuclear compaction in sperm. The highly specialized nuclear proteins in sperm create a chromatin structure that is at least six times denser than histone bound DNA. Unlike somatic cells, sperm DNA is highly compacted by the replacement of histones with sperm-specific low molecular weight proteins called protamines.

The clinical utility of the protamine 1/protamine 2 ratio in sperm.

During spermiogenesis, human sperm undergo a dramatic reorganization of the chromatin in which canonical histones are replaced by two types of protamines, protamine 1 (P1) and protamine (P2). P1 and P2 are expressed approximately at a 1:1 ratio in healthy men. Alteration of this ratio is associated with male infertility.

Association of aromatase (TTTAn) repeat polymorphism length and the relationship between obesity and decreased sperm concentration.

Background: Obesity in men is associated with low sperm count, however, this finding is inconsistent. Here, we describe length of the short tandem repeat aromatase (CYP19A1) polymorphism and its relationship to increased weight and sperm count.

Methods: A cohort of 215 men was recruited from the community and BMI, hormone levels and sperm parameters were determined at enrollment.

The marmoset and cotton rat as animal models for the study of sperm chromatin packaging.

In the human, canonical histones are largely replaced by protamine 1 (P1) and protamine 2 (P2) during late spermatogenesis. Recent studies have demonstrated that abnormal replacement of the histones is associated with severe male infertility and has profound implications for early embryogenesis. In this review the hispid cotton rat and the common marmoset are evaluated as animal models for the study of chromatin packaging in sperm.

Analysis of the meiotic recombination gene REC8 for sequence variations in a population with severe male factor infertility.

Proper regulation of meiosis is essential for normal spermatogenesis and abnormalities may be associated with infertility, as shown in both animal knockout studies and studies identifying anomalies in key proteins, such as SCP3 and MLH1. Disruptions of meiosis are associated with azoospermia or severe oligozoospermia, and may increase the incidence of sperm aneuploidy in some men. Based on its function and animal studies, REC8, a key component of the meiotic cohesion complex, has been identified as a candidate male infertility gene.

Novel UBE2B-associated polymorphisms in an azoospermic/oligozoospermic population.

Aim: To assess whether abnormalities exist in the UBE2B gene in a population of infertile human males, and to establish biologic plausibility of any discovered mutations.

Methods: We carried out polymerase chain reaction (PCR) amplification and sequence analysis of the 5'-untranslated region and six exons of the UBE2B gene, including flanking intronic regions, in a group of fertile and infertile men. Following the identification of a putative promoter region that contained single or dual triplet deletions within a 10-CGG repeat island, we evaluated the binding affinity of these identified polymorphisms as compared to the wild-type sequence to transcription factor SP1 using a DNA-protein gel shift assay.

Sequence analysis of the X-linked USP26 gene in severe male factor infertility patients and fertile controls.

The 1090C>T,L364F variant of the ubiquitin protease 26 (USP26) gene does not appear to be related to male infertility. Mutations of the USP26 gene do not appear to be a common cause of idiopathic azoospermia or severe oligozoospermia.

Comparative analysis of follicle morphology and oocyte diameter in four mammalian species (mouse, hamster, pig, and human).

Background: Laboratory animals are commonly used for evaluating the physiological properties of the mammalian ovarian follicle and the enclosed oocyte. The use of different species to determine the morphological relationship between the follicle and oocyte has led to a recognizable pattern of follicular stages, but differences in follicle size, oocyte diameter and granulosa cell proliferation are not consistent across the different species. In an effort to better understand how these differences are expressed across multiple species, this investigation evaluates oocyte and follicle diameters and granulosa cell proliferation in the mouse, hamster, pig, and human.

Comparison of chromatin assays for DNA fragmentation evaluation in human sperm.

Sperm chromatin integrity is vital for successful pregnancy and transmission of genetic material to the offspring. We evaluated chromatin integrity in sperm from 60 infertile men and 7 fertile donors comparing the sperm chromatin structure assay (SCSA), TdT-mediated-dUTP nick end labeling (TUNEL), the sperm chromatin dispersion (SCD) test, and acridine orange staining technique (AOT). The TUNEL and SCD assays showed a strong relationship with the SCSA (r > .

Primordial and pre-antral follicles are not commonly observed in IVF aspirates.

Background: Follicular fluid recovered from IVF patients has been proposed to be a valuable source of pre-antral and primary follicles for patient therapy and research. We evaluated the recovery of immature follicles in follicular fluid from 54 patients undergoing IVF using several techniques.

Methods: Fluid from each patient underwent several methods of follicle recovery including: filtration through a cell strainer, Ficoll-Paque density gradient, isolate density gradient, histological slide preparation, and enzymatic digestion with collagenase and DNase.