An assay was developed for simultaneous kinetic analysis of the activities of the bifunctional plant enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase [EC 4.1.1.39]. [1-(14)C,5-(3)H]Ribulose 1,5-bisphosphate (RuBP) was used as the labeled substrate. Tritium enrichment of the doubly labeled 3-phosphoglycerate (3-PGA) product, common to both enzyme activities, may be used to calculate V(c)/V...

To assess whether preload-adjusted maximal power (PAMP), which is calculated as W(max)/V (where W(max) is maximal power and V(ed) is end-diastolic volume with beta = 2) is an index of right ventricular (RV) contractility, we measured RV pressure (P) and volume (V) and pulmonary artery pressure and flow in 10 dogs at baseline and after inotropic stimulation. PAMP was derived from steady-state da...

Reflex, mechanical and histochemical adaptations of the soleus muscle following 3 weeks of hindlimb suspension (HS) were measured in the rat. HS transformed the soleus muscle fibre type composition from predominantly slow, type I, to approximately equal proportions of fast, type II and slow fibres. Consistent with this transformation was an increase in the maximum shortening velocity, V(max), a...

Assume that A is a bounded selfadjoint operator in a Hilbert space H. Then, the variational principle max v |(Au, v)| (Av, v) = (Au, u) (*) holds if and only if A ≥ 0, that is, if (Av, v) ≥ 0 for all v ∈ H. We define the left-hand side in (*) to be zero if (Av, v) = 0. As an application of this principle it is proved that C = max v∈L2(S) | ∫ S vdt| ∫ S ∫ S v(t)v(s)dsdt 4π|s−t| , (**) where L(S)...

To determine whether a 4-a-side handball (HB) game is an appropriate aerobic stimulus to reach and potentially enhance maximal oxygen uptake (V O(2)max), and whether heart rate (HR) is a valid index of V O(2) during a handball game. Nine skilled players (21.0+/-2.9 yr) underwent a graded maximal aerobic test (GT) where V O(2)max and HR-V O(2) relationship were determined. V O(2), HR and blood l...

The main nonhormonal mechanism for controlling inorganic phosphate (P(i)) homeostasis is renal adaptation of the proximal tubular P(i) transport rate to changes in dietary phosphate content. Opossum kidney (OK) cell line is an in vitro renal model that maintains the ability of renal adaptation to the extracellular P(i) concentration. We have studied how two competitive inhibitors of P(i) transp...

The maximum standardized uptake value (SUV(max)) varies among positron emission tomography-integrated computed tomography (PET/CT) centers in the staging of non-small cell lung cancer. We evaluated the ratio of the optimum SUV(max) cut-off for the lymph nodes to the median SUV(max) of the primary tumor (ratioSUV(max)) to determine SUV(max) variations between PET/CT scanners. The previously desc...

The purpose of this study was to examine differences in resting, submaximal, and maximal (V˙o 2 max) oxygen consumption (V˙o 2) in African-American ( n = 44) and Caucasian ( n = 31) prepubertal children aged 5-10 yr. RestingV˙o 2 was measured via indirect calorimetry in the fasted state. SubmaximalV˙o 2 andV˙o 2 max were determined during an all out, progressive treadmill exercise test appropri...

OBJECTIVE To evaluate the accuracy and diagnostic usefulness of a disposable flowmeter consisting of a plastic funnel with a spout divided into three chambers. MATERIALS AND METHODS Men with lower urinary tract symptoms (LUTS) voided sequentially into a standard flowmeter and the funnel device recording maximum flow rate (Q(max)) and voided volume (V(void)). The device was precalibrated such ...

We sought to describe cerebrovascular responses to incremental exercise and test the hypothesis that changes in cerebral oxygenation influence maximal performance. Eleven men cycled in three conditions: 1) sea level (SL); 2) acute hypoxia [AH; hypobaric chamber, inspired Po(2) (Pi(O(2))) 86 Torr]; and 3) chronic hypoxia [CH; 4,300 m, Pi(O(2)) 86 Torr]. At maximal work rate (W(max)), fraction of...