Reduction of centrifugation force in discontinuous percoll gradients increases in vitro fertilization rates without reducing bovine sperm recovery.

The objective of this study was to determine the effect of different centrifugation forces in bovine sperm separation by discontinuous Percoll gradients for in vitro fertilization IVF. The semen samples from each bull were pooled or each bull were centrifuged separately and centrifuged in discontinuous Percoll gradients (30, 60 and 90%) at different forces: F1 (9000×g), F2 (6500×g), F3 (4500×g) and F4 (2200×g), according experiment. The sperm samples were evaluated to determine the concentration, motility, vigor, morphology, reactive oxygen species (ROS), integrity of the plasma membrane, lipid peroxidation, antioxidants and embryo development were also evaluated.

Preemptive kidney transplantation: experience in two centers.

Introduction: End-stage renal disease (ESRD) is a prevalent, important cause of death. Transplantation increases survival and improves the quality of life of patients with ESRD while long-term dialysis is related to poor outcomes even among patients who undergo subsequent transplantations.

Objectives: To compare the advantages of preemptive procedures with kidney transplants among patients on renal replacement therapy.