We have examined the mechanisms of cell death induced by cisplatin in primary cultures of mouse proximal tubular cells. High concentrations of cisplatin (800 microM) led to necrotic cell death over a few hours. Much lower concentrations of cisplatin (8 microM) led to apoptosis, which caused loss of the cell monolayer over several days. Necrosis was characterized by a cytosolic swelling and early loss of plasma membrane integrity. In contrast, early features of cells undergoing apoptosis included cell shrinkage and loss of attachment to the monolayers. Nuclear chromatin became condensed and fragmented in apoptosing cells. These features were absent in necrotic cells. DNA electrophoresis of cells exposed to 800 microM cisplatin yielded a "smear" pattern, due to random DNA degradation. In contrast, the DNA of apoptosing cells demonstrated a "ladder" pattern resulting from internucleosomal DNA cleavage. Antioxidants delayed cisplatin-induced apoptosis but not necrosis. Thus the mechanism of cell death induced by cisplatin is concentration dependent. Reactive oxygen species play a role in mediating apoptosis but not necrosis induced by cisplatin.

We have examined the role of reactive oxygen species (ROS) in apoptosis induced by growth factor deprivation in primary cultures of mouse proximal tubular (MPT) cells. When confluent monolayers of MPT cells are deprived of all growth factors, the cells die by apoptosis over a 10- and 14-day period. Both epidermal growth factor (EGF) and high-dose insulin directly inhibit apoptosis of MPT cells deprived of growth factors. Growth factor deprivation results in an increase in the cellular levels of superoxide anion while apoptosis of MPT cells induced by growth factor withdrawal is inhibited by a number of antioxidants and scavengers of ROS. Growth factor deprivation also results in activation of caspase activity, which is inhibited by EGF and high-dose insulin as well as by the ROS scavengers and antioxidants that inhibit apoptosis. The cell-permeant caspase inhibitor, z-Val-Ala-Asp-CH2F (zVAD-fmk), prevents the increase in caspase activity and markedly inhibits apoptosis induced by growth factor deprivation. However, zVAD-fmk had no effect on the increased levels of superoxide associated with growth factor deprivation. Thus we provide novel evidence that ROS play an important role in mediating apoptosis associated with growth factor deprivation. ROS appear to act upstream of caspases in the apoptotic pathway. We hypothesize that oxidant stress, induced by growth factor withdrawal, represents a signaling mechanism for the default pathway of apoptosis.

Lysophosphatidic acid (LPA) is the smallest and structurally simplest of all glycerophospholipids. LPA is a normal constituent of serum and binds with high affinity to albumin while retaining its biological activity. The effects of LPA are pleiotropic and range from mitogenesis to stress fiber formation. In this report, we demonstrate two novel functions for LPA. LPA acts as a survival factor to inhibit apoptosis of primary cultures of mouse renal proximal tubular (MPT) cells. LPA also acts as a potent mitogen for MPT cells. The ability of LPA to act as both a survival factor and a mitogen is mediated by the lipid kinase phosphatidylinositol 3-kinase (PI3K), since these activities were completely blocked by wortmannin or LY-294002, two structurally dissimilar inhibitors of PI3K. The identification of LPA as a proliferative and anti-apoptotic factor suggests a potential role for this lipid mediator during the injury and/or recovery phases following tubular damage.

The chemoradiation therapy protocol is an alternative primary treatment modality for invasive urethral carcinoma. It enables an unprecedented potential for organ preservation.

A growing body of evidence suggests a genetic basis for the development of urogenital prolapse and stress incontinence. Candidate genes have been identified that may result in alteration of the normal metabolism of various structural proteins which may ultimately predispose some women to both urogenital prolapse and stress incontinence. Further research into the genetic basis of these conditions may provide a comprehensive understanding of the biological basis of these disorders.

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We demonstrate improved surgical outcome for ELRP with RUVA in regard to operative time, analgesic use, length of stay, leak rate, and complication rate. Long-term follow-up will determine whether a difference exists in disease recurrence, continence, and erectile function.

Laparoscopic radical prostatectomy has evolved over the last decade to become a common treatment for clinically localized prostate cancer at specialized institutions. During that time, various technical modifications have been pioneered by groups throughout the world. We present our technique of transperitoneal laparoscopic radical prostatectomy through a descending approach. We believe that the transperitoneal approach affords better visual landmarks, a larger operative space, and a stable pneumoperitoneum. Our technique employs a five-trocar approach to the prostate. All dissection and suturing is performed intracorporeally. The perioperative morbidity and short-term efficacy are similar to those of the open procedure.