Analysis of leukocyte and sperm telomere length in oligozoospermic men

Telomere length is considered one of the most relevant biological markers of genomic stability since it protects DNA from impairment and also ensures chromosome alignment during DNA replication. The negative impact of telomere shortening on sperm quality has been suggested as an important indicator of male infertility. Therefore, we aimed to assess leucocyte and sperm telomere length (LTL&STL), as well as sperm parameters, DNA damage and protamine deficiency in men with oligozoospermia as compared to fertile men. Our results demonstrated a significant reduction in sperm parameters (concentration, motility, morphology), LTL & STL and a significant increase in sperm DNA damage and protamine deficiency in oligozoospermic men compared with fertile individuals. These outcomes revealed that low sperm concentration in men is possibly a sign of impaired meiotic and/or meiotic division during the spermatogenesis process. It is not only associated with proper chromatin packaging but also with telomere length as a key player in the process of mitosis and meiosis, assisting in chromosomal alignment, pairing, synapsis and crossing over during spermatogenesis.     

A systematic review of barriers in access to renal transplantation among African Americans in the United States

BACKGROUND: African-American patients with end-stage renal disease are less likely than white patients to undergo renal transplantation. The development of strategies to address this disparity requires an evidence-based understanding of the barriers that impede access to renal transplantation among African Americans in the United States. METHODS: In September 2005, we searched MEDLINE, EMBASE, and CENTRAL for articles that identified the barriers that impeded African Americans' access to renal transplantation. Two reviewers independently extracted relevant data from the included studies. Barriers were broadly divided under two categories: (i) patient-related barriers; and (ii) healthcare-related barriers. RESULTS: We obtained 76 potentially relevant articles of which 11 studies were included in the final review. Several patient-related barriers--personal and cultural beliefs about transplantation, lower socioeconomic status and levels of education, and healthcare-related barriers--physician perception about survival of African Americans post-transplantation, inadequate transplant work-up despite being referred, and HLA-mismatching were identified at different stages of the transplantation process. Personal and cultural beliefs of African-American patients were consistently identified as patient-related barriers among several studies. Physicians' perception about post-transplantation survival of African Americans was the most commonly identified healthcare-related barrier. CONCLUSIONS: A wide spectrum of patient-related barriers including their personal and cultural beliefs about transplantation and several healthcare-related barriers at different stages of the transplant process impedes access to renal transplantation among African Americans in the United States. A multisectoral approach focusing on these barriers needs to be evaluated to reduce disparities in renal transplantation in the United States.     

Comparison of cross-sectional renal function measurements in African Americans with hypertensive nephrosclerosis and of primary formulas to estimate glomerular filtration rate

Renal function measurements were obtained in 1,703 African Americans with presumed hypertensive nephrosclerosis who were screened for entry into the African-American Study of Hypertension and Kidney Disease (AASK). We examined the effect of race on relationships involving renal variables by comparing African Americans enrolled into the AASK with non-African Americans enrolled into the Modification of Diet in Renal Disease (MDRD) study. We examined the effect of gender on renal variables by comparing African American men and women. We compared various methods for estimating glomerular filtration rate (GFR) with iodine 125-labeled (¹²⁵I)-iothalamate GFR. AASK data were also used to derive a new formula for estimating GFR in African Americans. After adjusting for age, sex, and baseline GFR, African American patients on the AASK study were heavier and had larger body surface areas and body mass indices than either MDRD African Americans or non-African Americans. African Americans had greater serum creatinine levels and urinary creatinine excretions for any given level of GFR. Mean GFR was greater in African American men than African American women (59.7 versus 51.7 mL/min/1.73 m²), although serum creatinine levels were also greater in men (1.91 versus 1.73 mg/dL). Seventy-eight percent of women with serum creatinine levels between 1.2 and 1.5 mg/dL had GFRs less than 65 mL/min/1.73 m². For African Americans in the AASK, GFR was overestimated by the 24-hour creatinine clearance and underestimated by the Cockcroft-Gault formula. A prediction formula developed in the MDRD study more accurately predicted GFR in AASK patients than these measurements. AASK data were also used to derive a new five-term formula for estimating GFR that was slightly more accurate in the African Americans in the AASK than the MDRD formula (median percentage of error, 12.4% for the MDRD formula versus 12.1% for the AASK formula). Important differences exist in renal variables between African Americans and non-African Americans and between African American men and African American women. Formulas using demographic data and readily measured serum values estimate ¹²⁵I-iothalamate GFR. © 2001 by the National Kidney Foundation, Inc.