Heat acclimation: role of norepinephrine in the anterior hypothalamus

The hypothesis that anterior hypothalamic (AH) sensitivity to norepinephrine (NE) is altered by chronic exercise in the heat was tested in male Sprague-Dawley rats. Treadmill exercise 6 days/wk for 3 wk at 21 m/min was performed at 23 degrees C (control; C) or at 35 degrees C (heat acclimated; HA), progressing from 20 to 50 min/day in 2 wk. Time for core temperature (Tco) to rise from 39.5 to 40.5 degrees C during a heat-tolerance test after conditioning increased (P less than 0.05) in the HA group. To test for a change in AH sensitivity, the change in Tco to 2-, 5-, 10-, 20-, and 40-micrograms doses of NE injected bilaterally into the AH was determined after conditioning. Dose-response regression lines showed that exercise in the heat increased the slope and shifted the Tco-NE dose relation to the left. In a separate series of experiments on 6 sedentary(s), 10 C, and 10 HA animals, the amounts of NE, dopamine, and 3,4-dihydroxyphenylglycol (DOPEG) were determined by high-pressure liquid chromatography in the AH, median preoptic area (PO), cortex, and cerebellum after 9 wk of conditioning. Results showed that in the PO there was a significant increase in NE and DOPEG in the HA vs. C group and a trend of increasing NE from the S to C to HA groups. The data indicate that exercise in the heat increases NE-induced peripheral heat-dissipating capacity and increases catecholamine storage in the PO.     

Chromatography And Biological Stains V. Isolation And Spectral Analysis Of The Orange Fat-Staining Component Of Sudan Iii

A sample of the orange fat-staining compound present in commercial Sudan III was isolated and purified by chromatographic methods. This material showed the presence of no other contaminating colored compounds when analyzed by paper chromatographic methods. Spectrographic analysis in the visible and ultra-violet ranges shows a strong absorption maximum at 481 mμ, a shoulder at approximately 425 mμ, and a weak absorption maximum at 315 mμ.     

Characterization of RNA transcripts and virally coded proteins synthesized in mouse fibroblasts transfected with hepatitis B DNA: HBeAg synthesis in HBcAg-negative cells with active core-antigen genes

A line of mouse cells expressing hepatitis B virus (HBV) surface and ‘e’ antigens identical in their physico-chemical properties to antigens from patients infected with HBV was isolated after transfection of 3T3 ceils with cloned HBV DNA. The studies reported here indicate that the ceils contain uninterrupted copies of the entire HBV genome which are unmethylated on CCGG sites and have no gross deletions or rearrangements. The entire core region is transcribed into polyadenylated RNAs large enough to serve as messengers for production of viral core antigen (HBcAg) yet no HBcAg can be detected. This suggests that the ceils produce a primary translation product copied from the HBcAg messenger which either cannot assume the proper configuration for display of HBcAg determinants or is rapidly converted to HBeAg by proteolysis.     

Synthesis and anti-ulcer activity of 16-phenoxy analogues of (+)-11-deoxyprostaglandin E1

( )-11-Deoxy-16-phenoxy-17,18,19,20-tetranor-prostaglandin E₁ is a highly potent and selective anti-ulcer agent. Analogues of this compound have been synthesized and structure-activity relationships are reported.     

Radiation chemistry of high-energy carbon, neon, and argon ions: hydroxyl radical yields

Chemical yields of H2O2 have been measured from aerated aqueous solutions of bromide and of formate irradiated at various pHs and solute concentrations with high-energy ions from the Berkeley Bevalac. Hydroxyl radical yields have been deduced from these data as a function of beam penetration into the solutions. By taking fragmentation of the primary ions into account, estimates of the instantaneous Gi OH values for the primary beams as a function of their energy have been made.