Biomedical subjects

N K Chung

Publications and source records attributed to N K Chung.

4 recordsLinked to original sources

PubMed1999

Cytokine levels in patients with previous heatstroke under heat stress.

We attempted to determine whether persons susceptible to heatstroke produced higher serum concentrations of interleukin-6, tumor necrosis factor-alpha, and interleukin-10 when subjected to heat stress. Nine patients with previous heatstroke and 21 matched controls were subjected to a heat-stress test (at 32 degrees C, 67% humidity, 900 W/m2 solar radiation, and wind speed of 2.5 m/s) for 60 minutes and rested at 24 degrees C for another 60 minutes in full battle gear. During the heat-stress test, blood was drawn at intervals of 0, 30, 60, and 120 minutes, and serum lipopolysaccharide, interleukin-6, tumor necrosis factor-alpha, and interleukin-10 concentrations were measured. Patients with previous heatstroke had a higher mean core temperature (0.6 degree C; p < 0.05) and sweated less (0.3 liters; p < 0.05). During the heat-stress test, the lipopolysaccharide levels were not increased and there was no difference in the serum cytokine concentrations between patients with previous heatstroke and controls. However, patients with previous heatstroke had higher absolute serum cytokine concentrations and poorer thermoregulatory response to heat stress in terms of core temperature and sweat loss.

Adult↗

PubMed1997

Tests of consequence monotonicity in decision making under uncertainty.

Consequence monotonicity means that if 2 gambles differ only in 1 consequence, the one having the better consequence is preferred. This property has been sustained in direct comparisons but apparently fails for some gamble pairs when they are ordered in terms of judged monetary certainty equivalents. In Experiments 1 and 3 a judgment procedure was compared with 2 variants of a choice procedure. Slightly fewer nonmonotonicities were found in one of the choice procedures, and, overall, fewer violations occurred than in previous studies. Experiments 2 and 3 showed that the difference was not due to procedural or stimulus presentation differences. Experiment 4 tested a noise model that suggested that the observed violations were due primarily to noise in estimating certainty equivalents, and so, despite some proportion of observed violations, consequence monotonicity cannot be rejected in that case.

Adult↗

PubMed1996

Obesity and the occurrence of heat disorders.

Obesity is often associated with poor heat tolerance. This case-control study was to determine the effect of obesity measured by the Body Mass Index (BMI) on the occurrence of heat disorders. The subjects, 218 soldiers with heat disorders and 537 controls, were matched for age and sex. Obesity was defined as a BMI of greater than 27. The odds ratio for obese soldiers was 3.53; however, their rectal temperatures were not significantly higher at presentation for heat disorder. The Physical Employment Standard (PES) classifies soldiers into A, B, C, and E depending on medical history at the time of enlistment. Soldiers with PES status of A and B were at a marginally higher risk of heat disorders. Correcting for the effect of the PES status, the odds ratio for obese soldiers was 4.29. Therefore, obese soldiers training in a hot and humid environment are at an increased risk of heat disorders.

Adult↗

PubMed1991

Modeling transitions in latent stage-sequential processes: a substance use prevention example.

This article illustrates the use of latent transition analysis (LTA), a methodology for testing stage-sequential models of individual growth. LTA is an outgrowth of latent class theory and is a particular type of latent Markov model emphasizing the use of multiple manifest indicators. LTA is used to compare the fit of two models of early adolescent substance use onset and to assess the effects of a school-based substance use prevention program on Ss measured in 7th grade and again in 8th grade. Several interesting findings emerged. First, a model of substance use onset including both alcohol and tobacco use as possible starting points fit better than a model that included alcohol use as the only starting point. Second, Ss who had tried tobacco but not alcohol in in 7th grade seemed to be on an accelerated onset trajectory. Third, the normative education prevention program was generally successful, except for the students who had tried only tobacco in 7th grade.

Age Factors↗