Young Subject

A recent paper [130] has also indicated that this interaction occurs in elderly patients. This is especially important since most interaction studies are typically performed in young subjects, yet the elderly are more likely to be taking the drugs that undergo this inter-... 

Bone, R. A. et al. (2007a). Macular pigment, photopigments and melanin Distributions in young subjects determined by four-wavelength reflectometry. Vision Research 47 3259-3268. 

BMI 19.8-36.0 kg m-2) were studied. All transit variables were unaffected by gender. The older subjects had a slower mean colonic transit time of radiolabeled plastic particles than the young subjects (p < 0.05), while BMI affected the gastric emptying of fiber but not other gastrointestinal variables [22]. In a more recent study, comparison was made between cohorts of young and elderly males, but no age-related effect could be determined [23]. 

The main rout of excretion of the drug and its metabolites is the kidney with a half-life of 9-18 h in human. In contrast to human, animal models have a lower elimination half-life ranging from 0.6-9 h [78]. The elimination half-life of valproic acid and some metabolites was found to be much longer in the neonates (40-50 h) than adult subjects (9-18 h) [78,81]. One study reported no difference between the elimination half-life between elderly and young subjects (15.4 and 13.0 h, respectively) while other found an increase in for older patients (14.9 versus 7.2 h for young patients) [78,90], Insignificant amounts of valproic acid are found in breast milk, approximately 3% of maternal drug levels [84]. 

The so-called normal range of blood and serum vitamin levels is always derived from observations on healthy young subjects. How about a comparison with healthy old subjects, whose percentage in the population is steadily increasing Much may be learned about the cause of the decrease of physiological function and of the increased susceptibility to organic disease in old age, if the role of vitamins as parameter of these alterations were investigated with a view to preventive theory. 

Notivol R, Carrio I, Cano L, Estorch M, Vilardell F. Gastric emptying of solid and liquid meals in healthy young subjects. Scand J Gastroenterol 1984 19 1107-1113. 

Cohen RM, Gross M, Semple WE, Nordahl TE, Sunderland T. (1994). The metabolic brain pattern of young subjects given scopolamine. Exp Brain Res. 100(1) 133-43. 

Elderly Plasma levels of carvedilol average about 50% higher in the elderly compared with young subjects. With the exception of dizziness (8.8% in the elderly vs 6% in younger patients), there were no events for which the incidence in the elderly exceeded that in the younger population by more than 2%. 

Elderly Clearance of fluvoxamine is decreased by about 50% in elderly patients. A lower starting dose of paroxetine is recommended. Sertraline plasma clearance may be lower. In 2 pharmacokinetic studies, citalopram AUC was increased by 23% and 30%, respectively, in elderly subjects as compared with younger subjects, and its half-life was increased by 30% and 50%, respectively. In 2 pharmacokinetic studies, escitalopram half-life was increased by approximately 50% in elderly subjects as compared with young subjects and C ax was unchanged. 

Elderly Data from clinical trials in patients with Alzheimer disease indicated that galantamine concentrations are 30% to 40% higher than in healthy young subjects. 

Ofloxacin - Maximum serum concentrations are achieved 1 to 2 hours after an oral dose. Steady-state concentrations are achieved after 4 doses. Ofloxacin is widely distributed to body tissues and fluids. Elimination is mainly by renal excretion 4% to 8% is excreted in the feces. A longer plasma half-life of about 6.4 to 7.4 hours was observed in elderly subjects, compared with 4 to 5 hours for young subjects. Dosage adjustment is necessary for patients with impaired renal function (Ccr 50 mL/min or less). 

Stroke is a major public health challenge, not only for neuropharmacology, but for the society in general. Stroke causes physical and psychological suffering for patients and their family, increased hospitalization burden, and premature death. Every year, there are 500,000 new stroke victims in the United States, and as many in Europe. Stroke is the third leading cause of death and can occur in young subjects under 55 years of age (estimated incidence = 34/100,000), especially in men. In the United States... 

Turnheim K, Krivanek P, Oberbauer R. Pharmacokinetics and pharmacodynamics of allopurinol in elderly and young subjects. Br 1 Clin Pharmacol 199948 501-509. 

The MSLT has been utilized in many studies to examine the effects of sleep deprivation on daytime sleepiness. As described earlier, Carskadon and Dement (11) performed the first MSLT study to test the effects of two nights of sleep loss in six young subjects. The scores fell to about 1 min at 0600 on the first night of sleep loss and remained at similarly low values throughout the sleep loss period. After one night of recovery sleep the scores remained significantly below baseline levels, which were not achieved until after the second recovery night. 

Bautmans, I. and Mets, T. (2005) A fatigue resistance test for elderly persons based on grip strength reliability and comparison with healthy young subjects. Aging Clin Exp Res 17, 217-222. 

Figure 4. A scanning electron micrograph showing the replicas of lacunae and canalicuh in situ in mandibular bone from a young subject aged 22 years. The inset shows enlarged lacunae identified by a rectangle. This micrograph illustrates the interconnectivity of the connected cellular network (CCN). Copied from Atkinson and Hallsworth (1983).

Fit young subjects had no impairment of their exercise ability after temazepam or nitrazepam, although nitrazepam caused a subjective feeling of hangover (77). 

The potential interaction of paroxetine 20 mg/day and alprazolam 1 mg/day for 15 days on polysomnographic sleep and subjective sleep and awakening quality has been evaluated in a randomized, double-blind, doubledummy, placebo-controlled, repeated-dose, four-period, crossover study in 22 young subjects with no history of sleep disturbances (29). There were subjective withdrawal symptoms after abrupt discontinuation of alprazolam, including increased subjective sleep latency and reduced subjective sleep efficiency. 

After an oral dose of 500 mg given to 6 young subjects, peak plasma concentrations of 2.65 to 4.0 pg/ml (mean 3.4) were attained in about 2 hours higher concentrations were reported when a similar dose was given to 6 elderly subjects (E. J. Triggs et al., Eur. J. din. Pharmac., 1980, 18,195-198). 

In an attempt to separate the normal effects of age from those due to visible atheromatosis, Lansing (1954) collected human aortas which possessed an over-all minimum of atheromatous plaques. Little difficulty was experienced in selecting suitable tissue from young subjects but considerable selection was necessary for the older specimens. From this material atheroma-free sections were cut out and the adventitia and intima were stripped off. Elastin was isolated from the separated tissue and its... 

Also at risk of hemolysis are patients with glucose-6-phosphate dehydrogenase deficiency, in whom ascorbic acid can denature hemoglobin and reduce erythrocjde glutathione concentrations one such case proved fatal (18). This was further demonstrated by reports of hemolytic effects (19) in two young subjects with glucose-6-phosphate dehydrogenase deficiency hemolysis was induced by excessive intake of fizzy drinks fortified with ascorbic acid (20). 

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