Regulation of taurine transporter activity in cultured rat retinal ganglion cells and rat retinal Muller cells

Diabetic retinopathy is one of the most common complications of diabetes. The amino acid taurine is believed to play an antioxidant protective role in diabetic retinopathy through the scavenging of the reactive species. It is not well established whether taurine uptake is altered in retinal cells during diabetic conditions. Thus, the present study was designed to investigate the changes in taurine transport in cultures of rat retinal Muller cells and rat retinal ganglion cells under conditions associated with diabetes. Taurine was abundantly up taken by rat retinal Muller cells and rat retinal ganglion cells under normal glycemic condition. Taurine was actively transported to rat Muller cells and rat retinal ganglion cells in a Na + and CI - dependent manner. Taurine uptake further significantly elevated in both types of cells after the incubation with high glucose concentration. This effect could be attributed to the increase in osmolarity. Because nitric oxide [NO] is a molecule implicated in the pathogenesis of diabetes, we also determined the activity of the taurine transporter in cultured rat retinal Muller cells and rat retinal ganglion cells in the presence of the NO donors, SIN-1 and SNAP. Taurine uptake was elevated above control values after 24-h incubation with low concentration of NO donors. We finally investigated the ability of neurotoxic glutamate to change taurine transporter activity in both types of cells. Uptake of taurine was significantly increased in rat retinal ganglion cells when only incubated with high concentration of glutamate. Our data provide evidence that taurine transporter is present in cultured rat retinal ganglion and Muller cells and is regulated by hyperosmolarity. The data are relevant to diseases such as diabetes and neuronal degeneration where retinal cell volume may dramatically change

role of some biochemical markers in predicting bone metastases in breast cancer patients

The study aimed to assess serum levels of BALP, CA 15-3, TGF-beta 1 and PTHrP in female patients with the stages II and IV of breast cancer in order to evaluate the role of these substances in the development and pathogenesis of bone metastases. This study was performed on 66 female patients with breast cancer, 42 patients with stage II and 24 patients with stage IV breast cancer [12 with bone metastases and 12 with non bone metastases]. Twelve healthy women were used as a control group. Liver function tests, kidney function tests and bone metabolism markers [serum calcium, phosphorus and bone specific alkaline phosphatase levels] were determined. Urinary calcium/creatinine and phosphorus/creatinine ratios and the incidence of proteinuria were calculated. Serum CA 15-3, TGF-beta 1 and PTHrP levels were estimated by enzyme linked immunosorbent assay [ELISA]