Genetics of serum dehydroepiandrosterone sulfate and its relationship to insulin in a population-based cohort of twin subjects

Previous studies have shown a significant effect of insulin administration on serum dehydroepiandrosterone sulfate (DHEA-S) concentration and its metabolic rate, with evidence for the effect in men, but not in women. This could lead to differences in the sources of variation in serum DHEA-S between men and women and in its covariation with insulin concentration. This study aimed to test whether these hypotheses were supported in a sample of healthy adult twins. Serum DHEA-S (n = 2287) and plasma insulin (n = 2436) were measured in samples from adult male and female twins recruited through the Australian Twin Registry. Models of genetic and environmental sources of variation and covariation were tested against the data. DHEA-S showed substantial genetic effects in both men and women after adjustment for covariates, including sex, age, body mass index, and time since the last meal. There was no significant phenotypic or genetic correlation between DHEA-S and insulin in either men or women. Despite the experimental evidence for insulin infusion producing a reduction in serum DHEA-S and some effect of meals on the observed DHEA-S concentration, there were no associations between insulin and DHEA-S at the population level. Variations in DHEA-S are due to age, sex, obesity, and substantial polygenic genetic influences.     

Reye's syndrome associated with acute myocarditis and fatal circulatory failure.

We describe an eight-month-old infant who had an unusually fulminant and fatal course of Reye's syndrome. The patient died 36 hours after admission because of irreversible circulatory failure not associated with clinical symptoms of increased intracranial pressure or cerebral herniation. Autopsy revealed the pathognomonic fatty degeneration of the liver and heart of Reye's syndrome, but the brain was normal. In addition, a marked inflammatory infiltration of the myocardium was also observed, which indicated that acute myocarditis had been the preceding underlying disease. This case report emphasizes the fact that the viral prodrome preceding Reye's syndrome may not be as benign as often observed with influenza and varicella. Acute myocarditis and Reye's syndrome are also a combination which may result in fatal cardiovascular collapse.     

Probing the low-frequency vibrational modes of viruses with Raman scattering--bacteriophage M13 in water

Raman spectroscopy is used to study low-wave-number (相似文献   

Ontogeny of arousal.

Ontogeny of arousal data constitute a vital supplement to the sparse literature on spontaneous neuronal activity. These data demonstrate that measurable infant spontaneous arousals (SAs) with an inherent oscillatory entrainment occur six times more in active sleep than in quiet sleep of the same duration and are identifiable as a human neurobiologic function. These SAs are not significantly associated with race or ethnicity, gender, total hours spent sleeping, percent time spent in active or quiet sleep, preterm status, history of a life-threatening event, having had a sibling who died of sudden infant death syndrome (SIDS), or having had a mother who smoked during this pregnancy. As measurable neurophysiologic events, SAs establish parameters for research at molecular and molar levels focusing on several critical areas: (1) the neuronal control of SA related to neurotransmitters, (2) as a significant antecedent factor in clinical cardiorespiratory events occurring in infants at high epidemiologic risk for SIDS; (3) as a regulatory biologic factor underlying temperament and executive cognitive functioning, and (4) morbidity and mortality effects possibly related to therapeutic interventions that alter SA levels.     

Pharmacokinetics of the trimethoprim-sulphamethoxazole combination in the elderly.

The pharmacokinetics of a co-trimoxazole preparation (Bactrim Forte) containing trimethoprim (TMP) 160 mg and sulphamethoxazole (SMZ) 800 mg were determined in six young adults (29.3 +/- 4.4 s.d. years) and six elderly people (78.6 +/- 6.6 s.d. years). Following oral administration of a single dose, the pharmacokinetic parameters of SMZ and its N4-acetylated metabolite (N4SMZ) were similar in both groups. However Cmax of TMP was greater (2.06 +/- 0.29 s.d. vs 1.57 +/- 0.32 s.d. mg l-1; P less than 0.01) and its area under the curve was larger (34.30 +/- 6.98 s.d. vs 23.87 +/- 3.82 s.d. mg l-1 h; P less than 0.001) in elderly people than in younger subjects. Total clearance (CL/F) of TMP normalized to body weight was not significantly different in the two groups. There was no significant difference in serum protein binding of TMP and SMZ between the two groups. Urinary excretion of TMP, SMZ and N4SMZ was reduced by about 50% in the elderly compared to the young subjects. Renal clearance of TMP was significantly lower in the elderly group (19 +/- 10 s.d. vs 55 +/- 14 s.d. ml h-1 kg-1; P less than 0.001). Renal clearance of SMZ was not significantly different in the two groups. A study of plasma concentrations of TMP, SMZ and N4SMZ during continuous dosing in seven elderly patients treated for urinary or respiratory infections showed that steady state was reached after 3 days of treatment and that plasma drug concentrations were about two to three times higher than those observed after a single dose.     

Relationships among the level of response to alcohol and the number of alcoholic relatives in predicting alcohol-related outcomes

BACKGROUND: The low level of response (LR) to alcohol is related to a family history (FH) of alcohol use disorders (AUDs), and each predicts alcohol-related outcomes. Few studies have evaluated the interrelationships between the number of alcoholic relatives, LR, and a range of alcohol-related outcomes. This study tests the hypotheses that there will be an inverse relationship between LR and FH and that LR will be a better predictor of the maximum quantity of alcohol consumed. METHODS: Data were extracted from personal interviews with 376 males from 20 years of follow-up in the San Diego Prospective Study. Level of response had been established at about age 20 through alcohol challenges in this population, about half of whom had at least one alcoholic relative. Face-to-face follow-ups with both the subjects and additional informants were carried out 10, 15, and 20 years later. These analyses used correlations and regressions to evaluate the relationship between the 2 major predictors (FH and LR) and 5 alcohol-related outcomes over 20 years of follow-up. RESULTS: As predicted, the alcohol challenge-based LR correlated significantly with the number of alcoholic relatives (up to -0.17 for subjects with clearly high and low LR scores). Each of the 2 predictors correlated with the 5 outcomes, including the maximum quantity of alcohol consumed since original testing, maximum frequency, nondiagnostic alcohol-related problems, the number of 11 DSM-IV (Fourth Diagnostic and Statistical Manual of Mental Disorders) abuse and dependence items, and having developed alcohol abuse or dependence. In hierarchical regression analyses, LR contributed significantly to the prediction of all 5 outcomes, even when considered in the context of FH, with only LR predicting drinking quantity and frequency, but both items adding to the prediction of alcohol-related problems and diagnoses. These results were not affected by the intensity of usual drinking when LR had been measured at age 20. CONCLUSIONS: Both FH and LR contributed to a range of alcohol-related outcomes, with LR alone significantly predicting maximum quantity and frequency in regression analyses.     

Effect of navigation direction on the dual-task of counting backward during blind navigation

Blind navigation towards a remembered target is associated with large direction errors when executed with a side stepping walking pattern. To investigate whether sideways navigation requires higher attention resource than forward navigation, a dual-task paradigm of backward counting during blind navigation was used. The objectives were to determine the effect of this dual-task on navigation errors, gait velocity and the rate of backward counting and to establish whether this effect is larger during sideways than forward navigation. A group of 17 subjects participated. The primary task was to navigate without vision towards previously seen targets located on the floor 8m away in four directions (ahead, behind, to the right or left) and to stop at the place the target was presumed to be. Forward, backward and side stepping gait patterns were used to reach corresponding targets. The secondary task was to count backwards in steps of three. The dual-task was to perform blind navigation while counting backwards. The rate of backward counting was significantly decreased in the dual-task relative to a controlled sitting condition (p<0.05), but this reduction was similar among navigation directions. Navigation errors were not changed between navigation only and dual-task. Gait velocity was significantly slower in the dual-task than in navigation only (p<0.05). This suggests that counting backward while navigating without vision towards a remembered target exceeded the subjects' attention capacity. However, sideways navigation did not seem to require more attention than forward navigation, even though navigation was much less precise in sideways than forward navigation.