Basal and high potassium-stimulated release of endogenous amino acids was measured using brain dialysis in the hippocampus of urethane-anesthetized seizure-resistant (SR) and seizure-susceptible (SS) rats. Moreover, the tissue level of amino acids was determined in the hippocampus, sensorimotor cortex, cerebellum and corpus striatum. The basal extracellular concentration of amino acids did not differ between SR and SS rats. However, aspartate release was higher, and taurine and phosphoethanolamine release was lower in SS rats during stimulation with 100 mM K+. Several strain differences were observed with regard to regional tissue levels of amino acids. Aspartate was significantly elevated in the hippocampus, cortex and cerebellum of SS animals, and the catecholamine precursor tyrosine was diminished in all regions examined. Other disparities included a depressed gamma-aminobutyrate concentration in the hippocampus and cortex, slightly increased levels of phosphoethanolamine in the cerebellum and minor decreases in striatal and cortical taurine. Glutamate, glutamine, serine and alanine concentrations were not significantly altered in any brain area of the SS rat. The results confirm and extend previous findings on abnormalities in aspartate, taurine and phosphoethanolamine regulation in this model. In addition, decreased availability of tyrosine may provide a partial explanation for the well-documented deficiency in cerebral norepinephrine in the SS strain.

Amino Acids↗

PubMedDate not supplied

Does long-term exposure to gel-filled silicone implants increase the risk of relapse after breast cancer?

BACKGROUND: An increased risk of cancer and autoimmune diseases associated with gel-filled silicone implants, debated by FDA experts since 1991, has given rise to a profusion of literature on the subject. However, such effects have not been adequately investigated in patients with breast cancer. In a previous report we compared 146 breast cancer patients with gel-filled silicone implants for breast reconstruction to 146 control patients in whom no reconstruction had been performed. The observed results were reassuring, as the evolution of the disease after 10 years was better in the reconstruction group than in the control group. We now report the end results of this study with a median follow-up of 13 years after the breast reconstruction (range, 10-20 years). METHOD: The relative risks of detrimental events were estimated with Cox's Proportional Hazards Model, with stratification according to age at diagnosis. RESULTS: The risks of locoregional recurrences and distant metastasis were significantly lower in the BR group than in the control group. The risks of death, of a second breast cancer and of a second primary cancer at a site other than the breast were not significantly different between the two groups of patients. CONCLUSION: Long-term follow-up of patients exposed to gel-filled silicone implants confirms the absence of detrimental effects after breast cancer. The power of our study is, however, below that required to detect a very slight increase in the risks studied.

Adult↗