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At least 307 records · Page 17Linked to original sources
PubMed1993

The contribution of individual variables to Hotelling's T2, Wilks' lambda, and R2.

We examine the effect of each variable on the following statistics: the one-sample and two-sample Hotelling's T2, Wilks' lambda for multivariate analysis of variance, and R2 in multiple regression. For T2, the net effect of each variable is an increase in the multivariate statistic, and the particular factors determining the amount of increase are (i) the multiple correlation of the variable with all other variables, and (ii) how well the variable's contribution to falsifying the hypothesis can be linearly predicted from the other variables. The effect of each predictor variable on R2 is similar to the effect of each variable on T2. For Wilks' lambda, each variable induces a decrease, due to (i) the F for that variable alone, and (ii) the change in multiple correlation from within-sample to total-sample.

Analysis of Variance↗
PubMedDate not supplied

Maximum expiratory flow-volume curves in children: changes with growth and individual variability.

Environmental factors may affect the lungs of children by retarding growth of ventilatory capacity. To detect retarded growth, we recorded maximum expiratory flow-volume (MEFV) curves in boys and girls aged 8-14 years observing the normal patterns of growth. The accuracy with which deviations from the normal patterns of growth may be measured was also determined. Expiratory flow rates and timed expiratory volumes were less reproducible in the same child than was forced vital capacity. At all ages the shape of girls' MEFV curves was different from that of boys curves in that girls had greater maximum expiratory flow rates (Vmax.) when differences in forced vital capacity (FVC) had been taken into account. The ratio of Vmax. 50% FVC to FVC decreased in both boys and girls as they grew older. The rates of growth of the MEFV curve measurements and estimates of their reproducibility were used to calculate minimum sample sizes required to detect retarded growth of ventilatory capacity. To detect a change of 10% in the normal growth rate in Vmax. 50% FVC between ages 8 and 14 years, nearly 2,000 children would need to be studied annually. Smaller samples could be used if changes in FVC growth rates were of primary concern.

Adolescent↗
PubMed1995

[Individual variability in the number of stem cells in mammalian tissues].

The distribution of animal groups (3--4 control or gamma-irradiated mice per group) were obtained when analysing published data on the mean number of the CFUs in the femoral bone marrow or stem cells of small intestinal crypt. Almost 50% of such groups have the mean number less than the geometric mean. The mean value for the group of animals deviation from the expected geometric mean for all animal population for more than 2.5 times, both for the larger values and for the smaller, was about 5% in such groups for the marrow CFUs and 20% for intestinal stem cells. The percentage of mice, that died from acute radiation sickness after acute irradiation, was related with the parameter D(0), that characterized the CFUs survivability on the exponential part of the survivability curve. The negative correlation (r = -0.83) was determined between the mean value of the small intestine crypt stem cells and the ability of intestinal stem cells to the radiation damage reparation, evaluated through the parameter D(q) of the stem enterocyte survival curve for this animal groups.

Acute Disease↗
PubMed1996

[Individual variability of pharmacokinetic parameters of amikacin in the elderly: retrospective studies].

UNLABELLED: In previous works, we have shown: i) good parameter predictive performances of the USC*PACK Clinical Programs for amikacin therapy in the elderly, ii) no significant difference generally detected between estimated parameter values at days 7 and 14 after the beginning of therapy, iii) assurance of neither accumulation nor toxicity during therapy up to 14 days or more, in our conditions. The objectives of this study were to explore which elements best explained differences found in the pharmacokinetic parameters (PK) of the elderly patients, who had received several courses of amikacin therapy. METHODS: patients' pharmacokinetic data and their medical records were retrospectively analyzed. Only patients who received amikacin therapy with at least a 2-month washout between their courses were studied. Two parameterizations of the 1-compartment PK model were used: one without covariates: Kel-Vol, where Kel = elimination rate constant and Vol = distribution volume, and another including covariates: Ks-Vs, with: Kel = Ks. CCr + Ki, where: Ks = renal fraction of Kel, Ki - non renal elimination, CCr = estimated creatinine clearance, and Vs = Vol/W, where Vs = distribution volume per kg and W = weight. RESULTS: 14 patients, 3 men and 11 women, fulfilled the criteria (4 of them satisfied the condition with 3 courses). They were 66 to 89 years old, their mean weight was 53.86 +/- 11.03 kg (46-71.5), their CCr averaged: 55.45 +/- 17.16 mL/min (14.84-96.27). CONCLUSION: Among patients exhibiting changes (67%) in PK parameters between different courses of therapy, 42% could have the variability related to covariate (W, CCr) changes; in the others 58% the residual variability could be explained by different factors: severity of infection, immune system deficiency and/or particularly parenteral nutrition. Based on these result, we suggest including septic choc and parenteral nutrition as covariates during amikacin adaptive control.

Age Factors↗
PubMed1997

[Individual variability in the topography of the thoracic duct and its significance for the treatment of chylothorax by a video endosurgical method].

A possibility for clipping the ends of the damaged thoracic duct in chylothorax treatment by video endosurgical method was supported by the experiment performed in 10 dogs and topographoanatomical study carried out in 158 corpses of adults. The correlation found allows to forecast the possible position of thoracic region of the thoracic duct both by the thoracic cage shape and topography of the adjacent large anatomic elements.

Adult↗
PubMed1998

Systematic biopsy-based staging of prostate cancer: scientific background, individual variables, combination of parameters, and current integrative models.

Staging of the prostate cancer remains the mainstay of treatment decisions and prognostication. Multiple staging tests, which are currently available, fail to provide optimal staging accuracy in the management of prostate cancer. Systemic biopsy can provide useful data regarding bilaterality, Gleason grade, cancer map, perineural infiltration, tumor volume, percentage cancer and microvessel density. We have reviewed existing literature on systematic biopsy in this review. We have further discussed the role of neural network technology in integrating this information.

Biopsy↗