Preconditioning hippocampal slices with hypothermia promotes rapid tolerance to hypoxic depolarization and swelling: Mediation by erythropoietin.

We suggested previously that hippocampal slices were protected from hypoxic depolarization and swelling by preincubating them at room temperature (Kreisman et al., 2000). We postulated that hypothermic preconditioning induced tolerance in our slices, which protected against hypoxic depolarization and swelling. Control hippocampal slices were incubated at 34-35 °C for two hours and the response to 10 min of severe hypoxia was compared to slices which were preconditioned for two hours at room temperature (22-23 °C) prior to warming to 34-35 °C. Recordings of the extracellular DC potential provided an index of tissue depolarization and changes in tissue light transmittance provided an index of swelling. Hypothermic preconditioning significantly reduced hypoxia-induced swelling, particularly in CA3 and the dentate inner blade. Since erythropoietin (EPO) had been shown to mediate hypoxic preconditioning, we tested whether EPO also mediated hypothermic preconditioning in our slices. Recombinant rat EPO (1-10 micromolar) mitigated hypoxia-induced swelling and depolarization in dentate inner blade of unconditioned slices in a dose-dependent manner. We also blocked the protective effects of hypothermic preconditioning on hypoxic depolarization and swelling in the inner blade of the dentate gyrus by administering soluble EPO receptor in the bath and treating slices with wortmannin to block phosphorylation of PI3 kinase, a critical step in the activation of the downstream neuroprotectant, Akt. These results suggest that EPO mediates tolerance to hypoxic depolarization and swelling induced by hypothermic preconditioning. They also emphasize that various preincubation protocols used in experiments with hippocampal slices may differentially affect basal electrophysiological and metabolic properties of those slices.

A Whole Blood Assay for AR-V7 and ARv567es in Patients with Prostate Cancer.

PURPOSE: Most prostate cancer mortality can be attributed to metastatic castration resistant prostate cancer, an advanced stage that remains incurable despite recent advances. The AR (androgen receptor) signaling axis remains active in castration resistant prostate cancer. Recent studies suggest that expression of the AR-V (AR splice variant) AR-V7 may underlie resistance to abiraterone and enzalutamide. However, controversy exists over the optimal assay. Our objective was to develop a fast and sensitive assay for AR-Vs in patients. MATERIALS AND METHODS: Two approaches were assessed in this study. The first approach was based on depletion of leukocytes and the second one used RNA purified directly from whole blood preserved in PAXgene® tubes. Transcript expression was analyzed by quantitative reverse transcription-polymerase chain reaction. RESULTS: Through a side-by-side comparison we found that the whole blood approach was suitable to detect AR-Vs. The specificity of the assay was corroborated in a cancer-free cohort. Using the PAXgene assay samples from a cohort of 46 patients with castration resistant prostate cancer were analyzed. Overall, AR-V7 and ARv567es were detected in 67.53% and 29.87% of samples, respectively. Statistical analysis revealed a strong association of AR-V positivity with a history of second line hormonal therapies. CONCLUSIONS: To our knowledge this is the first study to demonstrate that PAXgene preserved whole blood can be used to obtain clinically relevant information regarding the expression of 2 AR-Vs. These data on a castration resistant prostate cancer cohort support a role for AR-Vs in resistance to therapies targeting the AR ligand-binding domain.

Alternative Digit Ratios and Their Relationship to Prostate Cancer.

BACKGROUND: The ratio of the second to the fourth digits (2D:4D) has been linked to prenatal androgen exposure and prostate cancer (PCa). The use of alternative finger ratios has been shown to be a greater indicator of sexual dimorphism when compared with the traditional 2D:4D ratio. This study aimed to assess the relationship between alternative digit ratios, racial demographics, and clinical/pathologic parameters associated with PCa. MATERIALS AND METHODS: Digital finger length measurements were made from scanned images of hands from patients with PCa. Race, age, family history, history of metastasis, and Gleason score at diagnosis were assessed in a cross-sectional clinic-based study. Demographic and clinical parameters were analyzed with respect to various alternative finger length ratios. RESULTS: Hand measurements were obtained in 354 white and 98 African-American patients with PCa. African-American men were more likely to have a smaller 2D:3D (P < .0001) and 2D:4D digit ratio (P < .0001) in both hands. Larger right (R)3D:5D (P = .0005), R4D:5D (P = .0014), and R2T:2D (P = .0501) digit ratios were present in African-Americans compared with whites. In exploratory analyses, African-American men with a smaller left (L)2T:2D ratio were younger at the time of PCa diagnosis (P = .0125). No relationship was found between the various digit ratios and Gleason score, the presence of metastatic disease, or family history. CONCLUSION: Various alternative finger length ratios show strong differences between African-American and white men in this study. The potential relationship between the 2T:2D ratio and age at diagnosis in African-Americans needs additional verification.