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Zero Time (zero + time)
Selected AbstractsPost-prandial glucose excursions following four methods of bolus insulin administration in subjects with Type 1 diabetesDIABETIC MEDICINE, Issue 4 2002H. P. Chase Abstract Aims To determine if one method of short-acting insulin bolus administration is superior to other methods in managing a meal high in carbohydrates, calories and fat. Methods Nine subjects receiving continuous subcutaneous insulin infusion using insulin lispro (Humalog®) agreed to consume the same meal high in carbohydrates, calories and fat on four occasions 1 week apart. They received the same dose of bolus insulin on each of the four occasions randomly assigned and beginning 10 min prior to the meal as either a single bolus, two separate boluses of one-half the same total dose (the second after 90 min), the entire bolus given as a square-wave (over 2 h) or a dual-wave (70% as a bolus and 30% as a square-wave over 2 h). Blood glucose levels were measured at ,60 and ,30 min and at zero time, and then every half-hour for 6 h using the Hemacue® in the out-patient clinic. Results Changes in blood glucose values from fasting were the lowest after 90 and 120 min (P < 0.01) when the dual wave was administered. When the dual or square-wave methods of insulin administration were used, subjects had significantly lower glucose levels after 4 h in comparison with when the single or double boluses were used (P = 0.04). Conclusions We conclude that the dual wave provided the most effective method of insulin administration for this meal. The dual- and square-wave therapies resulted in lower glucose levels 4 h after the meal in comparison with the single and double-bolus treatments. [source] Monitoring of headspace volatiles in milk-cereal-based liquid infant foods during storageEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 12 2006Guadalupe García-Llatas Abstract The effect of storage (time and temperature) on the evolution of pentanal, hexanal, heptanal and pentane as volatile lipid oxidation products in two liquid ready-to-eat milk-cereal-based infant foods was studied. An SPME-GC method was used to this effect. Samples were stored for 9,months at 25, 30 and 37,°C and tested eight times during this period. Freshly produced infant foods contained pentanal, hexanal and heptanal (mean values: 10.71, 71.5 and 1.2,µg/kg, respectively), which decreased during the first 3,months of storage, although from the fourth month onwards no significant differences among storage times were found. Aldehyde content was inversely proportional to storage temperature. Pentane content was directly proportional to storage temperature and increased (19.9,µg/kg at zero time) over all months of storage up to 43.1,µg/kg. [source] Influence of endotoxin on the disposition kinetics and dosage regimens of oxytetracycline in calvesJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2003R. Kumar The influence of endotoxin on the disposition kinetics of oxytetracycline (OTC) (10 mg/kg) was investigated in five healthy ruminating male crossbred calves. The serum concentration-time data of OTC before and after endotoxin challenge were best described by a two-compartment open model. Repeated administration of Escherichia coli endotoxin (1 ,g/kg, i.v.) at an interval of 12 h up to 48 h produced a clear rise in the body temperature and an increase in the pulse and respiration rates. Endotoxin caused a significant reduction in mean transit time in tissue compartment (MTTT) (P , 0.05), mean residence time in the peripheral tissue compartment (MRTT) (P , 0.05), mean residence time in the body (MRTB) (P , 0.05), elimination half-life (t1/2,2) (P , 0.05) and distribution space in tissues (VT) (P , 0.01) and at steady-state (Vd(ss)) (P , 0.01). Endotoxin had no effect on the distribution clearance (ClD), systemic clearance (Cl) and distribution half-life of OTC, while the values of first order rate constant of transfer of drug from tissue to central compartment (K21) and the zero time intercept at terminal phase (C2) were significantly high. The drug dosage regimens to maintain serum OTC concentrations of 0.5, 1, 2, 4, 6 and 8 ,g/mL were also determined in febrile and clinically healthy animals. [source] The MRI-measured arterial input function resulting from a bolus injection of Gd-DTPA in a rat model of stroke slightly underestimates that of Gd-[14C]DTPA and marginally overestimates the blood-to-brain influx rate constant determined by Patlak plotsMAGNETIC RESONANCE IN MEDICINE, Issue 6 2010Tavarekere N. Nagaraja Abstract The hypothesis that the arterial input function (AIF) of gadolinium-diethylenetriaminepentaacetic acid injected by intravenous bolus and measured by the change in the T1 -relaxation rate (,R1; R1 = 1/T1) of superior sagittal sinus blood (AIF-I) approximates the AIF of 14C-labeled gadolinium-diethylenetriaminepentaacetic acid measured in arterial blood (reference AIF) was tested in a rat stroke model (n = 13). Contrary to the hypothesis, the initial part of the ,R1 -time curve was underestimated, and the area under the normalized curve for AIF-I was about 15% lower than that for the reference AIF. Hypothetical AIFs for gadolinium-diethylenetriaminepentaacetic acid were derived from the reference AIF values and averaged to obtain a cohort-averaged AIF. Influx rate constants (Ki) and proton distribution volumes at zero time (Vp + Vo) were estimated with Patlak plots of AIF-I, hypothetical AIFs, and cohort-averaged AIFs and tissue ,R1 data. For the regions of interest, the Kis estimated with AIF-I were slightly but not significantly higher than those obtained with hypothetical AIFs and cohort-averaged AIF. In contrast, Vp + Vo was significantly higher when calculated with AIF-I. Similar estimates of Ki and Vp + Vo were obtained with hypothetical AIFs and cohort-averaged AIF. In summary, AIF-I underestimated the reference AIF; this shortcoming had little effect on the Ki calculated by Patlak plot but produced a significant overestimation of Vp + Vo. Magn Reson Med 63:1502,1509, 2010. © 2010 Wiley-Liss, Inc. [source] Glycocalyx volume: a critical review of tracer dilution methods for its measurementMICROCIRCULATION, Issue 3 2009CHARLES. ABSTRACT A clinical measure of endothelial glycocalyx structure would have great potential importance, because lesions of the glycocalyx may be the first changes to occur in diabetes and in a wide range of vascular diseases. A method recently described by Nieuwdorp et al. for estimating the volume of the luminal glycocalyx of the entire human vascular system would seem to be the first attempt to develop a measure of this kind. It is based on the tracer dilution principle, and this review considers the principles and conditions that underlie this method and the extent to which the conditions appear to have been fulfilled in this case. Our analysis raises two questions about 1) the estimation of the concentration of the tracer (dextran 40) at zero time and 2) the estimation of plasma volume, both of which can be answered by changes in experimental protocol. A third question, concerning the partition coefficient of the tracer between plasma and the fluid within the glycocalyx, cannot be answered at the present time, and until it has been resolved, glycocalyx volume cannot be estimated from the dilution of a macromolecular tracer. [source] | ||||||||||