We describe the results of a survey of the UV absorption properties of the Boroson & Green sample of AGN, which extends from the Seyfert (MV ≃ −21) to the luminous quasar (MV ≃ −27) level. The survey is based mostly on HST archival data available for > ∼ 1/2 of the 87 sample objects. Our main result is that soft X-ray weak quasars (SXWQs, 10 AGN with αox ≤ −2) show the strongest UV absorption a...

Mitochondrial ATP production is vital for meeting cellular energy demand at rest and during periods of high ATP turnover. We hypothesized that high-intensity interval training (HIT) would increase ATP flux in resting muscle (VPi→ATP) in response to a single bout of exercise, whereas changes in the capacity for oxidative ATP production (Vmax) would require repeated bouts. Eight untrained men (27...

The regulation of plasma membrane L-arginine transport activity was investigated in differentiated and undifferentiated states of the human intestinal cell line, Caco-2. The sodium-independent, leucine-insensitive uptake of L-arginine measured in this study has been assigned by us previously to system y+ in Caco-2 cells. Treatment of cells with serum-free media containing epidermal growth facto...

High speed oscilloscopic recordings (4000 mm/sec) of left ventricular pressure (micromanometer) and its first derivative were used to calculate contractile element velocity (Vce) during the isovolumic period of auxotonic beats in anesthetized dogs. At 0.5-2.0 msec intervals of isovolumic systole, Vce was derived as (dP/dt)/kP, where k = 24 cm(-1). Plots of Vce and P yielded inverse curves from ...

The metabolism of nortriptyline was studied in vitro using cDNA-expressed human cytochrome P450 isozymes 1A2, 3A4, 2C19, and 2D6, CYP2D6 was the sole isozyme mediating hydroxylation of nortriptyline, the quantitatively most important metabolic pathway, and only (E)-10-OH-nortriptyline was formed. CYP2D6, 2C19, and 1A2, mentioned in decreasing order of significance, mediated the demethylation re...

To investigate the effects of intermittent heavy exercise (HE) on sarcoplasmic reticulum (SR) maximal Ca2+-ATPase activity (Vmax) and Ca2+ uptake, a continuous two-stage standardized cycling test was performed before and after HE by untrained men [peak aerobic power (Vo -->Vo2 peak) = 42.9 +/- 2.7 ml. kg-1 x min-1]. The HE consisted of 16 bouts of cycling performed for 6 min each hour at 90% Vo...

The effect of electrostatic screening of fixed negative charges on uncoupled mitochondrial electron transport was investigated with substrates with different charge and different sites of donation of electrons to the electron-transport chain of Jerusalem-artichoke (Helianthus tuberosus L.) mitochondria. Duroquinol (neutral substrate) was oxidized with a pH optimum of 7.6-7.8. The addition of ca...

The objective of this study was to evaluate the toxicokinetics and metabolism of pseudocumene after inhalation exposure. Male Wistar rats were exposed to pseudocumene vapors at nominal concentrations of 25,100 or 250 ppm in the dynamic inhalation chambers for 6 h. Blood samples were collected during (between 1st and 6th h) and after exposure (betwen 6th min and 6th h). Blood concentrations of p...

OBJECTIVE Left ventricle (LV) transmural gradient in mitochondrial respiration has been recently reported. However, to date, the physiological mechanisms involved in the lower endocardium mitochondrial respiration chain capacity still remain to be determined. Since, nitric oxide (NO) synthase expression in the heart has spatial heterogeneity and might impair mitochondrial function, we investiga...