Novel chiral calix[4]arenes by direct asymmetric epoxidation reaction.

We report the first asymmetric synthesis of trans optically active (+) C 2 1,3-bisarylepoxide of calix[4]arene in excellent chemical yield and >99% ee, and its enantiospecific conversion to the corresponding bis-dioxolane.

The effect of shear stress on the basolateral membrane potential of proximal convoluted tubule of the rat kidney.

As consequence of glomerular filtration the viscosity of blood flowing through the efferent arteriole increases. Recently, we found that shear stress modulates proximal bicarbonate reabsorption and nitric oxide (NO.) was the chemical mediator of this effect.

Modifications of the pituitary-thyroid axis induced by hypobaric hypoxia.

The effects of simulated altitude induced by a decompression chamber upon the blood levels of thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3), measured by radioimmunoassay, were studied in male Wistar rats. When blood was extracted during the first 15 minutes after the rats were removed from the chamber and analysed, it was found that TSH levels decreased at 380 mmHg during 24 hours and sometimes at 440 mmHg during 24 hours, but this did not happen when the exposure lasted a week. Likewise, serum levels of T4 and T3 decreased at 440 mmHg during 24 hours, but they did not decrease using the same exposure during a week.