Five healthy young men exercised on an ergocycle for six 25-min periods separated by 5-min rest intervals in a warm dry environment (36 degrees C). After 1 h of exercise without fluid intake, the ...subjects continued to be dehydrated or were rehydrated either with water (W) or with isosmotic electrolyte carbohydrate solutions, either acidic (AISO) or close to neutrality (NISO). The average amount of the fluid ingested progressively every 10 min (120 ml) at 20 degrees C was calculated so as to compensate for 80% of the whole body water loss due to exercise in the heat. Dehydration associated with hyperosmotic hypovolaemia elicited large increases in heart rate (HR), and in rectal temperature (Tre), while no decrease was found in either whole body or local sweat rates. Rehydration with water significantly reduced the observed disturbances, except for plasma osmolality and Na+ concentration which were significantly lower than normal. With both AISO and NISO there was no plasma volume reduction and osmolality increase. Although a plasma volume expansion was induced by NISO ingestion, the cardiac cost was not improved, as reflected by the absence of a decrease in HR. With NISO, sweating was not enhanced and Tre tended to remain higher. It is concluded that efficient rehydration requires the avoidance of plasma volume expansion at the expense of interstitial and intracellular rehydration. During rehydration by oral ingestion of fluid, the pH of the drink may be an important factor; its effect remains unclear, however.
Pooled plasma from healthy volunteers was spiked with pure, synthetic chlorpromazine (CPZ), chlorpromazine sulfoxide (CPZSO), or chlorpromazine N-oxide (CPZNO), and then made alkaline with either ...sodium hydroxide or sodium carbonate. The samples were allowed to stand at room temperature for various timed intervals before extraction with organic solvent. It was found that CPZNO was reduced to CPZ in plasma made alkaline with sodium hydroxide, but not in protein-free buffer solution at high pH nor in plasma made alkaline with sodium carbonate. The reaction appears to take place through reducing equivalents generated by the action of sodium hydroxide on plasma proteins. Thus, apparent concentrations of CPZ in plasma from patients were elevated by as much as 343% when sodium hydroxide was used compared with concentrations in aliquots of the same plasma samples alkalinized with sodium carbonate. The amount of CPZ produced from CPZNO depends on the type of extraction procedure employed as well as on the quantity of sodium hydroxide added to the plasma. By contrast, no interconversion between CPZ and CPZSO or CPZNO and CPZSO was observed in plasma alkalinized and extracted under any of the conditions tested.
Previous studies have reported that mercury accumulates in cord blood during pregnancy. This study was carried out to determine where in cord blood the mercury accumulates, i.e., in cord ...erythrocytes, in cord plasma, or in both, and to determine whether the predominant form of mercury which accumulates is methyl or inorganic mercury. From our data it is clear that methyl mercury accumulates in cord erythrocytes: A total of 30% more methyl mercury was found in fetal erythrocytes than in maternal erythrocytes. Also correlation analysis of the methyl mercury levels in maternal and fetal erythrocytes showed a strong correlation (r = 0.87). In regard to inorganic mercury, the highest concentration was found in the placenta, suggesting a barrier role, but a significant correlation (r = 0.62) was also found between the maternal and fetal plasma levels of inorganic mercury. Moreover, the inorganic mercury concentration per gram of plasma was higher in fetal cord plasma than in maternal plasma. Overall, the relative levels of methyl and inorganic mercury reported here varied considerably in materrnal and fetal erythrocytes, plasma, and in the placenta, but all of the levels were low (<6 ng Hg/gm of tissue) and in agreement with Øtotal¿ mercury levels reported by others.
A new device, the Periotron 6000®, has been proposed to estimate small amounts of gingival crevicular fluid. In the present investigation, small volumes of four different liquids (saline, saliva, ...plasma, and crevicular fluid) collected with small capillaries have been delivered on to Periopaper® strips. The amounts of liquids on the strips were determined with the Periotron.
High correlations between the fluid volumes and the Periotron readings were found. A calibration curve of the measurements made with crevicular fluid with its 5% tolerance and confidence limits is given. The slope of linear regression found in our investigation was at 3.5 nl per unit, thus significantly below that described by the manufacturer (5 nl/unit). Taking into account this fact, the Periotron, however, is a very reliable device to study gingival crevicular fluid in clinical investigations.
Constant transmembrane pressure experiments were made by crossflow filtration to clarify sieving characteristics of microporous glass membranes for plasma fractionation. The distribution of pore ...diameters is more limited in the microporous glass membranes than in currently utilized synthetic polymer membranes. The filtration resistance of the concentration polarization layer is the dominant factor in plasma fractionation. Proteins are separated more sharply with a higher wall shear rate because of destruction of the concentration polarization layer formed on membrane surfaces. Plasma fractionation using a microporous glass membrane with a pore diameter of 15 nm may allow separation of albumin and IgG at higher wall shear rates. Cascade filtration techniques using microporous glass membranes with various pore diameters may be suitable for plasma fractionation.
Antibodies specific to chlorpromazine N-oxide (CPZNO) were produced in rabbits immunized with a hapten-bovine serum albumin conjugate, which was prepared by linking the 7-position of the ...phenothiazine ring of the metabolite to the protein via a 4-carbon bridge. An extraction radioimmunoassay (RIA) was developed using this antiserum and shown to have adequate sensitivity and specificity for determination of plasma concentrations of CPZNO in the presence of chlorpromazine (CPZ) and its major metabolites. It was used together with the previously developed RIAs for CPZ, chlorpromazine sulfoxide (CPZSO), and 7-hydroxychlorpromazine (7-OHCPZ) to study the pharmacokinetics of CPZ and these metabolites in five healthy volunteers after they received a single 50-mg oral dose of CPZ. It is interesting to note that peak plasma concentrations of CPZNO were considerably higher than CPZ, and the apparent elimination half-lives of this metabolite were shorter than those of CPZ.
Concentrations of selenium in whole blood, plasma, and leucocytes were determined in 16 patients with coeliac disease confirmed by biopsy and 32 controls. All the patients were clinically well and ...receiving gluten free diets. The concentrations of selenium were significantly lower in the leucocytes, blood, and plasma of patients compared with controls, probably indicating a decrease in the body content of selenium. A high incidence of malignancy in coeliac disease has been reported. As a protective role for selenium against cancer has been postulated, the importance of this unexpected observation of lowered tissue concentrations of selenium requires further investigation.
The results of this study have shown large interpatient variability in the disposition of M17 and M1 following a single oral dose of CsA in pretransplant end-stage renal disease patients. The ...differences in the distribution of M17 and M1 in WB and P at 37 degrees C has particular relevance in the interpretation of CsA therapeutic drug monitoring by nonspecific assays such as the RIA. Additional studies characterizing the disposition of M17 and M1 in WB and P separated at 37 degrees C following chronic CsA therapy will be needed to further understand the role of these metabolites in therapeutic drug monitoring of CsA. New analytical techniques or refinements in the present techniques will be required to identify and separate coeluting substances that are now being recognized with the present techniques.
PDF
