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At least 307 records · Page 17Linked to original sources
PubMed1991

Metabolism of carbamazepine: evidence of autoinduction in Chinese.

To investigate the autoinduction of carbamazepine (CBZ) metabolism in Chinese, eleven healthy male volunteers joined in this study. There were two phases of drug administration with a wash-out interval of one month, 400 mg CBZ was taken orally in single-dose phase, and 200 mg three times per day were given for seven days in multiple-dose phase. Plasma samples were obtained in series of time after the last dose of drug in each phase. CBZ concentrations were determined by a high pressure liquid chromatography method. A non-linear regression program was applied in a personal computer to estimate the pharmacokinetic parameters. The average CBZ half-lives in single- and multiple-dose phases were 50.1 +/- 12.1 (mean +/- SD) hours and 26.1 +/- 4.2 hours and the clearances were 16.4 +/- 3.3 ml/kg/h and 45.3 +/- 23.4 ml/kg/h respectively, both with significant differences (p less than 0.005). There is evidence to support the presumption of autoinduction in Chinese.

Adult↗
PubMed1991

Open-loop feedback control of serum bentazepam concentrations and Bayesian estimation in multiple dosage regimens in patients.

The time course of serum levels of bentazepam was studied in 10 patients receiving anxiolytic agent orally at a dose of 25 mg on multiple dosage regimens with dosage intervals of 8 and 12 h. Using the methods of "open-loop feedback control", no linear regression programs and Bayesian estimation, it was possible to establish the best estimates of the pharmacokinetic parameters corresponding to the single-compartment model for each patient from all their data relating to the serum levels obtained after the first dose and after multiple dosing with different regimens. The application of the Kruskal Wallis test showed that there were only statistical differences for the absorption constant, determined with and without Bayesian estimation. However, no statistically significant differences were found on comparing the experimentally obtained serum levels with the corresponding theoretical values calculated independently for each patient from the parameters established with and without Bayesian estimation. As population pharmacokinetic parameters of bentazepam, the following were established: Ka = 2.330 +/- 0.665 l/h; Vd = 1.209 +/- 0.546 l/Kg and Ke = 0.160 +/- 0.118 l/h, corresponding to a mean value for the elimination half-life of 4.33 h.

Administration, Oral↗
PubMed1991

A heuristic approach to nurse scheduling in hospital units with non-stationary, urgent demand, and a fixed staff size.

We present a practical approach to personnel scheduling problems arising in hospital units with demand that is of an urgent nature, cannot be backlogged, and is highly dependent on the time of day. A simple rounding heuristic is combined with a simulated annealing algorithm to obtain near-optimal solutions to large linear integer programming models of these personnel scheduling problems in a reasonable amount of time on a personal computer. The models are designed to complement the current state-of-the-art of commercially available hospital staff scheduling systems.

Algorithms↗
PubMed1991

[Analysis of the circadian rhythm of pain].

An electronic pulp tester was used to study the stimulus threshold in human teeth of 28 healthy volunteers for 1,5-4 days and the duration of local anaesthesia in 55 patients with caries. Rhythm analysis was performed with a non-linear fitting program on an IBM computer (PHARMFIT); in 21 out of the 28 volunteers significant daily rhythms in stimulus threshold could be detected. In the patients the maximum duration of local anaesthesia was after drug application at 2 p.m.

Adolescent↗
PubMed1991

[Demographic and economic trends in medical schemes--a time series analysis].

A time series analysis was performed on medical scheme statistics with the aim of determining current and future demographic and economic trends. This would enable one to reach a better perspective on the current and future financial dilemma presently experienced by medical schemes. Data for the period 1978-1986 was analysed on a computer, using the Statgraphics program. The linear trend projection method, based on the regression analysis technique was used. Real values were determined by deflating nominal values against the consumer price index with 1980 as base year. There are at present 253 medical schemes in operation. Approximately 16 per cent of the economically active population are members of medical schemes. White members increased by only 3.8 per cent during the period 1978-1986, in comparison to the 87.1 per cent by black members. The beneficiaries represent 19 per cent of the total population; black beneficiaries increased by 422.1 per cent, while Whites increased only fractionally by 0.73 per cent. Membership fees increased by an average of R8.08/member/month or R1.72/member/month in real terms. Ninety five per cent of the income of medical schemes was derived from membership fees. The average real growth rate of income was 8.4 per cent, while net assets increased by only 3 per cent. An average deficit of R11.02 million/year is estimated for the recommended reserve funds in real terms. The greatest proportion of benefits paid was for professional services (47.4 per cent) followed by medicine (26.3 per cent) and hospital services (19.8 per cent). The real growth rate for benefits paid was 8.6 per cent per year.(ABSTRACT TRUNCATED AT 250 WORDS)

Economics↗
PubMedDate not supplied

Quantitative multiresidue analyses for volatile organics in water and milk, using a fused silica open-tubular wide-bore capillary column and automated headspace gas chromatography.

A modified multiresidue capillary gas chromatographic (GC) procedure has been developed using automated headspace sampling and a wide-bore fused silica open-tubular (FSOT) capillary column for the determination of volatiles in water and milk. Compounds are quantitated by the method of standard additions. An IBM System 9000 computer with the CAPMC3 chromatographic applications package and a BASIC linear regression program are used for data reduction. Data are presented for solutions prepared by fortifying water and milk with volatile solvents such as acetone, methyl ethyl ketone, benzene, methylene chloride, and chloroform, which are commonly used in the manufacture of packaging materials and adhesives. The wide-bore FSOT capillary columns showed dramatically improved detection for certain compounds, compared with normal-bore capillary GC columns. Data presented for various chemicals demonstrate the improved limits of detection from the use of automated headspace gas chromatography with wide-bore capillary columns and flame ionization detection.

Animals↗
PubMedDate not supplied

[A low-frequency magnetic field and regeneration of bony tissue of the jaw: optimization of exposure parameters (experimental research)].

The optimal parameters of exposure to low-frequency magnetic field were chosen in experiments with 132 rats, using a simplex method of the extreme exposure. These parameters are as follows: 22 mT induction, length of exposure 20 min, pulse regimen. Exposure in such conditions provides the most effective influence of magnetic field on the reparative osteogenesis and mineralization processes and on the subsequent organic restructuring of the bone at the site of the mandibular standard defect.

Animals↗
PubMed1989

When are additive models valid for evaluating proposed research?

This paper is concerned with a comparison of two broad classes of mathematical models, additive and multiplicative, for selecting the best among a number of competing project proposals addressed to a defined research objective. The analysis is predicated on the view that, though additive models are widely utilized, they are theoretically inferior to multiplicative ones. In an effort to more clearly understand when the use of additive models might be acceptable despite their logical flaws, conditions are investigated under which they yield results that are essentially equivalent to those produced by multiplicative models.

Cost-Benefit Analysis↗
PubMed1989

Eating problems and nutritional status during hospital stay of patients with severe stroke.

Eating problems and nutritional status were studied in a consecutive series of patients who had had strokes. From this cohort, 32 subjects (mean age 73 years) with a hospital stay of 21 days or more are described. Eating problems were identified by direct participant observations of the patients' eating behavior, interviews on admission, inspections of the mouth, and discussions with the patients. Nutritional status was assessed by weight, triceps skinfold thickness (TSF), arm muscular circumference (AMC), plasma albumin, serum transferrin, and plasma prealbumin on admission and then weekly. Eating problems were identified in 27 patients. In a general linear hypothesis program, poor nutritional status 3 weeks after admission was found to be associated with (in decreasing order) low self-care performance, poor nutritional status on admission, male sex, intravenous energy-containing fluids, advanced age, paresis of the right arm, and eating problems. Factors other than eating problems seem to be important for undernutrition in patients with strokes during hospital stay.

Cerebrovascular Disorders↗
PubMed1977

Quantitative structure-activity relationships. V. A simple simple algorithm for Fujita-Ban and Free-Wilson analyses.

For quantitative structure-activity analyses a simple algorithm for the calculation of de novo group contributions by Fujita-Ban analysis is given. This algorithm corresponds in all details to a computer program for linear multiple regression analysis. However, the transformation of the original matrix to the normal equations matrix is easily achieved without a computer. The normal equations matrix can be solved with a modern desk calculator being equipped with a matrix ROM. Two examples are given to explain the algorithm; the calculation of all important statistical parameters is illustrated. As for quantitative structure-activity analyses this algorithm can be applied as well for the calculation of other additive parameters, such as pi from log P-values or omega from equilibrium constants.

Electronic Data Processing↗
PubMedDate not supplied

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Computers↗