Both ritonavir and indinavir were readily metabolized by human intestinal microsomes. Comparison of the patterns of metabolites in incubations with enterocyte microsomes and expressed cytochrome P450 (CYP) isozymes and immunoinhibition and chemical inhibition studies showed the essential role of the CYP3A subfamily in the metabolism of both protease inhibitors by the small intestine. Ritonavir ...

We have performed a detailed V/Vmax test for a sample of the Canada-France Redshift Survey (CFRS) for the purpose of examining whether the comoving number density of field galaxies changes significantly at redshifts of z < 1. Taking into account the luminosity evolution of galaxies which depends on their morphological type through different history of star formation, we obtain 〈V/Vmax〉 ≈ 0.5 in...

We have studied maturational changes in the kinetics of the proximal tubule Na+/H+ antiporter. Microvillus membrane vesicles were prepared from renal cortex of fetal and newborn lambs. Amiloride-sensitive uptake of 22Na+ by these vesicles was measured and Woolf-Augustinsson-Hofstee plots were used to determine the Michaelis constant (Km) and rate of maximal uptake (Vmax). Initial studies of fet...

This study aimed to determine the time-dependent effects of diaphragmatic inactivity on its maximum shortening velocity (Vmax) and the Muscle Atrophy F-box (MAF-box, atrogin-1) gene expression during controlled mechanical ventilation (CMV). Twenty-four New Zealand White rabbits were grouped into 1 day, 2 days and 3 days of CMV and controls in equal numbers. The in vitro isotonic contractile pro...

We measured the response to breathing a mixture of 80% helium and 20% oxygen (He) during a maximum expiratory flow-volume (MEFV) maneuver in 66 nonsmokers and 48 smokers, aged 17-67. All of the subjects studied had (forced expiratory volume in 1 s/forced vital capacity [FEV(1.0)/FVC]) x 100 of greater than 70%. While the flow rates of the smokers were within +/-2 SD of those of the nonsmokers a...

Maximal velocity (Vmax) is a well established biomarker for the assessment of tissue redox status. There is scarce evidence, though, that it does not probably reflect sufficiently in vivo tissue redox profile. Instead, the Michaelis constant (Km) could more adequately image tissue oxidative stress and, thus, be a more physiologically relevant redox biomarker. Therefore, the aim of the present s...

We compared the effects of lidocaine, 2 X 10(-5) M, on transmembrane resting and action potentials of Purkinje fibers on the endocardial surface of 24- to 72-hour-old myocardial infarcts in dogs with its actions and subendocardial Purkinje fibers in normal hearts. At both proximal (near the tip of the papillary muscle) and distal (toward the apex) recording sites in noninfarcted hearts, lidocai...

Different myosin isoenzymes of pig and human atrium and ventricle and rat ventricle were characterized by two approaches: pyrophosphate polyacrylamide gel electrophoresis (PP-PAGE) and analysis of the myosin P light chains by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). We further investigated the relation between atrial and ventricular myosin isoenzymes of human, pig, and rat,...

Undoubtedly, the DLVO theory has been and it is still very useful for explaining the stability of colloidal dispersions. This theory was independently developed by Derjaguin and Landau [1] and by Verwey and Overbeek [2] in the forties. According to this theory, the total interaction potential (VT) between two colloidal particles is the sum of the repulsive electrostatic interaction energy (VE) ...

Variegate porphyria (VP) is characterized by photocutaneous lesions and acute neuropsychiatric attacks. Decreased protoporphyrinogen oxidase activity results in accumulation of protoporphyrin (ogen) IX and coproporphyrin (ogen) III. During acute attacks delta-aminolevulinic acid and porphobilinogen also increase, suggesting that porphobilinogen deaminase (PBG-D) may be rate limiting. We have ex...