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991.
992.
The attribute(s) of soluble dietary fibers responsible for cholesterol lowering is currently uncertain. A series of experiments were conducted in which viscosity and fermentability was assessed independently for their effect on plasma and liver cholesterol concentration. Hamsters were divided into four dietary groups and fed diets containing 0.12% cholesterol and 5% fiber as high viscosity hydroxypropyl methylcellulose (HV-HPMC group), low viscosity hydroxypropyl methylcellulose (LV-HPMC group), high viscosity guar gum (HV-GG group) or low viscosity guar gum (LV-GG group). Hydroxypropyl methylcellulose is essentially nonfermentable, whereas guar gum is highly fermentable. Plasma cholesterol concentrations at 3, 6 and 11 wk and liver cholesterol concentrations at 6 and 11 wk were significantly lower in the HV-HPMC group relative to the LV-HPMC group (P < 0.05). Intestinal content viscosities of the LV-HPMC and HV-GG groups were similar; consequently, these two groups were compared to examine the independent effect of fermentation. Plasma and liver cholesterol were significantly lower in the HV-GG group compared with the LV-HPMC group at 6 wk (P < 0.05), but not at 3 or 11 wk. Hepatic sterol synthesis rates were not affected by any of the diets. This study shows that greater viscosity of intestinal contents is strongly associated with cholesterol reduction, but that the contribution of fiber fermentation remains uncertain. 相似文献
993.
994.
Z Hussein KJ Patterson JE Lamm JH Cavanaugh GR Granneman 《Canadian Metallurgical Quarterly》1993,14(5):389-399
The pharmacokinetics of intravenously administered valproic acid (VPA) were investigated in 16 healthy male volunteers in a single-dose, fasting, four-period, randomized, double-blind, placebo-controlled, parallel design study. Subjects were randomly assigned to be infused a single dose of sodium valproate equivalent to 1000 mg VPA or placebo over each of four different time periods. Valproate concentrations in plasma were determined using gas chromatography with flame ionization detection. The pharmacokinetic parameters were determined by both non-compartmental and model-dependent techniques. Analyses of variance (ANOVAs) were performed to detect any statistical differences among the regimens. Overall, the pharmacokinetic of valproate were similar after infusions of 5, 10, 30, and 60 min, with an average terminal-phase half-life of 15.9 h. There were modest differences in overall clearances among the regimens, with the 5 min infusion producing a mean area under the plasma concentration-time curve (AUC; 1877 micrograms.h ml-1) that was significantly (13 to 16 per cent) higher than the means for the longer infusions (1614-1656 micrograms.h ml-1). Differences in distribution were also noted as a function of infusion duration. The shortest duration produced a significantly smaller terminal volume of distribution (12.8 vs 14.2-15.1 l) and more rapid tissue equilibration. The alpha-phase rate constant declined from a mean of 5.1 h-1 after the 5 min infusion to a mean of 0.9 h-1 after the 60 min infusion. The distributional differences are almost certainly related to the saturable protein binding of valproate. However, the lower clearance after the 5 min infusion indicates that there may have also been partial saturation of one of the metabolic pathways of valproate during the distributive phase, and that the increase in fu was smaller than the decrease in CL'int, such that the product of fu.CL'int showed a net decrease. 相似文献
995.
996.
DW Loring AM Murro KJ Meador GP Lee CA Gratton ME Nichols BB Gallagher DW King JR Smith 《Canadian Metallurgical Quarterly》1993,43(9):1789-1793
We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate seizure localization in 20 patients with complex partial seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery. 相似文献
997.
KJ Radke 《Canadian Metallurgical Quarterly》1994,21(4):181-90; quiz 191-3
The effects of normal aging on the kidney are both structural and functional. Morphologic changes involve the renal blood vessels, glomeruli, tubules, and interstitium. Physiologic changes include alterations in renal plasma flow, glomerular filtration rate, filtration fraction, tubular transport, concentrating ability, acidification, the renal handling of electrolytes, and patterns of urine flow and electrolyte excretion. The structural and functional changes that occur in the senescent kidney, and the implications for nursing practice are discussed. 相似文献
998.
999.
Seasickness is the most prevalent form of motion sickness and is an operational problem during Space Shuttle Solid-fueled Rocket Booster (SRB) retrieval. Phenytoin has been shown to protect against motion sickness induced by Coriolis stress. We exposed SRB recovery personnel to off-vertical rotation and sea motion after phenytoin or placebo. Phenytoin blood levels of at least 9 micrograms/ml were protective against motion sickness at sea. No change in susceptibility to nitrogen narcosis was seen in divers in chamber tests at 460 KPa. Phenytoin was used during performance of critical and hazardous tasks during training and actual SRB recovery operations. Phenytoin is an effective operational countermeasure for motion sickness for selected SRB crewmembers. 相似文献
1000.
AIM: To examine the haemodynamic effects of intravenous magnesium sulphate on an animal model of neonatal pulmonary hypertension induced by hypoxia. METHODS: The cardiac index (Q), pulmonary arterial pressure (PAP), systemic arterial pressure (SAP), and pulmonary (PVRI) and systemic (SVRI) vascular resistance indices were measured in nine newborn piglets (including three controls). Pulmonary hypertension was induced by lowering the FIO2 to 0.12-0.14, after which there was a significant increase in PAP and PVRI (37% and 142%, respectively; p < 0.01) and a significant fall in SAP and Q (30% and 33%, respectively; p < 0.01). RESULTS: Magnesium sulphate was infused intravenously as four doses of 25 mg/kg, 15 minutes apart, which resulted in a significant mean (SD) increase in serum magnesium (0.83 (0.07) mmol/l to 1.82 (0.19) mmol/l; p < 0.01). After the initial dose SAP, SVRI, PAP and PVRI decreased, but not significantly. Each subsequent dose of (50, 75, 100 mg/kg) was accompanied by further significant reductions in these variables from control baseline (p < 0.05). The PVRI:SVRI ratio remained unchanged throughout. Inhaled nitric oxide (NO) 40 ppm was administered after the last dose of magnesium sulphate. The PVRI:SVRI significantly decreased (p < 0.05), indicating that reversible pulmonary hypertension remained after a maximum dose of magnesium sulphate. CONCLUSIONS: Unlike NO, magnesium sulphate is not a selective pulmonary vasodilator and may lead to deleterious effects on systemic pressures in critically ill newborns. 相似文献