Subjects, healthy variability

While the absorption of adrenaline from a subcutaneous injection in healthy subjects is variable (and sometimes very slow) absorption from an inhaled dose is rapid and reliable (16). The main adverse effect from the inhaled route, for example in a dose of 3-4.5 mg, is gastrointestinal discomfort, with nausea and sometimes vomiting this seems to be a local effect since it does not occur with injections. However, both forms produce mild tremor and palpitation in some individuals. 

The above examples of PCA applications deal with a two-way data analysis (subjects and variables). A three-way PCA (subjects, variables, and conditions) has shown that trace metal concentrations can be used to classify healthy and diseased blue crabs [72]. 

Colonic residence time is considerably longer than in other parts of the GIT, and it is also more variable. The transit time can be as short as several hours to as long as 50 60 hours. Transit along the colon is characterized by abrupt movement and long periods of stasis. In one study of 49 healthy subjects the average colonic residence time was 35 hours with the following times associated with different regions 11 hours in the... 

The ratio, [Li ]/[Li+ut], in human erythrocytes ranges from 0.2-0.9, illustrating a large inter-individual variability however this ratio is relatively constant over long periods of time for individuals and there is evidence that this phenomena is under genetic control [62]. Higher ratios have been reported in patients with affective illnesses compared to healthy subjects [63] and in females compared to males [64]. There have been attempts to correlate the higher Li+ ratio to a better clinical response of patients to Li+ therapy [65]. 

Balogh, A., Harder, S., Vollandt, R. and Staib, A.H. (1992) Intra-individual variability of caffeine elimination in healthy subjects. International Journal of Clinical Pharmacology, Therapy, and Toxicology, 30 (10), 383—387. 

In addition to the greater risk in patients, results in patients are frequently confounded by the effects of disease, concomitant medication, age and other variables. By contrast, healthy subjects are much more homogeneous and subjects are studied under standardised conditions. It is sometimes argued that healthy volunteers are not representative of the patient population and therefore that the studies are of less... 

To reveal the cognition-enhancing potential of the S-HTj antagonists, studies in age-related memory impairment have been carried out with psy-chiatrically healthy subjects impaired with scopolamine and patients with dementia. In a randomized double-blind, double-dummy, four-way crossover study in a small number of subjects, each psychiatrically healthy male subject received placebo, scopolamine [0.4 mg im], scopolamine plus alosetron [10 J,g iv], or alosetron [250 Jg] [Preston 1994 Preston et al. 1991). Assessments of verbal and spatial memory, sedation, and sustained attention were performed before and after treatment. The main results from the study were that scopolamine induced robust deficits on all primary variables measured, the reduction in verbal and spatial memories being attenuated by 10- Jg and 250- Jg doses of alosetron, respectively. No effects on the sedation or on changes in attention were noted. 

Our study group consisted of 167 individuals, of whom 99 were healthy women controls and 68 breast cancer cases. The experimental group was comprised of women who had been diagnosed with breast cancer at the Department of Medical Oncology, Mersin University, Turkey. Controls were selected by taking age and sex variable into consideration. Genomic DNA from breast cancer patients and control subjects was analyzed by PCR-RFLP. 

Hamilton, M.J., Smith, P.R., and Peck, A.W., Effects of bupropion, nomifensine and dexamphetamine on performance, subjective feelings, autonomic variables and electroencephalogram in healthy volunteers, Br J. Clin. Pharmacol., 15, 367, 1983. 

Fig. 12.4 Pharmacokinetic-pharmacodynamic model ofthethrombopoietic effects of a thrombopoietin analogue (PEG-rHuMGDF) in healthy volunteers. The intrinsic longevity of platelets (A), nonlinear random destruction of platelets (p), and the intra-subject variability...

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