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Biomedical subjects

J F Walker

Publications and source records attributed to J F Walker.

At least 37 records · Page 2Linked to original sources
PubMed1995

The effect of body fat distribution on pulmonary function tests.

Although the influence of obesity on pulmonary function tests has been examined, the role of body fat distribution has received limited attention. Pulmonary studies of patients severely affected by upper body obesity suggest they have more severely compromised lung volumes than obese patients with lower body obesity. We examined 42 healthy but normal or mildly obese men to determine if body fat distribution influences pulmonary function tests. Multiple measures of adiposity showed a significant inverse relationship with both spirometry and static lung volumes. However, the biceps skinfold thickness had the strongest inverse relationship with total lung capacity (TLC) compared to other anthropometric measures. The waist-to-hip ratio (WHR) demonstrated a significant inverse relationship with static lung volumes only when controlling for cigarette smoking. However, comparing pulmonary function tests between patients with a WHR less than 0.950 (lower body fat distribution) and subjects with a WHR of 0.950 or greater (upper body fat distribution) revealed that FVC, FEV1, and TLC were significantly lower in the patients with upper body fat distribution. Stepwise multiple regression analysis was done using all anthropometric variables and age which generated predictive equations that included the biceps skinfold thickness for residual volume (RV) and TLC. This suggests that upper body fat distribution may be associated with a modest impairment of lung volumes in normal and mildly obese men. Until the findings of this study can be applied to a larger, ethnically and anthropometrically diverse population, and to women, we believe caution is warranted when standard equations are used to predict pulmonary function tests in an anthropometrically diverse population.

Adipose Tissue↗
PubMed1994

Bioremediation of petroleum hydrocarbons in soil column lysimeters from Kwajalein island.

Soil column studies were used to evaluate petroleum hydrocarbon (PHC) remediation in soils from Kwajalein Atoll. Treatments included controls, and combinations of water, air, nutrients, and bioaugmentation with indigenous microbes (W, A, N, and M, respectively). Microbial colony forming units (CFU) decreased in the control columns and in treatments without air. Treatments including W+A+N and W+A+N+ exhibited increased CFU. One third of the PHC was removed by water and another third was removed by W+A+N and W+A+N+M treatments. Bioaugmentation with indigenous PHC degraders did not enhance bioremediation. Potential for bioremediation was demonstrated by air, water, and nutrient amendments.

Air↗
PubMed1994

Effect of caffeine and/or cigarette smoking on resting energy expenditure.

The thermic effect of cigarette smoking is dampened by the thermic effect of a meal, but potentiated by the thermic effect of exercise. The impact of the combined influences of caffeine and cigarette smoking is unknown. We examined the 3-h thermic response to smoking four 0.8 mg nicotine cigarettes, ingesting 200 mg of caffeine, or both, in ten fasted healthy men. Smoking four 0.8 mg nicotine cigarettes increased resting energy expenditure (REE) by 3.3% over a 3 h measurement period. Consumption of 200 mg of caffeine in the fasted condition increased REE of the smokers by 4.8% over 3 hours. Smoking four 0.8 mg cigarettes and ingesting 200 mg of caffeine significantly increased REE by 7.5% during the 3 h measurement period. At times early in the observation period, the combined thermic effect of cigarettes and caffeine was more than additive, but the effect was short-lived. A control group of nonsmokers was studied comparing REE following placebo or 200 mg of caffeine. Caffeine increased REE in the non-smoking controls 6.7%. This was not significantly different from results obtained on smokers. Fasted and non-smoking (baseline) REE was similar in smokers and non-smoking control subjects. It was concluded that the effects of caffeine on REE are additive.

Adolescent↗
PubMed1993

Body fatness and smoking history predict the thermic effect of smoking in fasted men.

Epidemiological studies suggest that body composition and smoking history are related to degree of weight gain following smoking cessation. We hypothesized that body composition and smoking history affect the thermic effect of smoking (TES), which in turn would influence weight gain. Forty males ranging in age from 20 to 70 years smoked two cigarettes (0.8 mg nicotine yield) in 20 minutes, after which resting energy expenditure (REE) was measured during the next hour. The average change in REE (delta REE) was 4.97% (P < 0.0001), with a range of -2% to +14%. delta REE was greater than 1% in 35 subjects, less than 1% in three subjects, and reduced in two subjects. Body fatness was negatively correlated with delta REE (r = -0.68, r2 = 0.46). Multiple regression analysis indicated that body fatness (%) and pack-year history of smoking strongly predict delta REE (R = 0.82, R2 = 0.68; delta REE = 11.090-0.296 x %FAT-0.037 x pack-year). It was concluded that body fatness and smoking history substantially influence the thermic effect of smoking. In addition, this finding helps explain the wide range in TES which has been reported among subjects in many previous studies.

Adipose Tissue↗
PubMed1992

Articulation rate in 3- and 5-year-old children.

The major purposes of this study were to provide normative data on articulation rate in preschool children and to examine the influence on articulation rate of age, gender, context, and utterance length. The subjects were twenty 3-year-old children and twenty 5-year-old children, equally balanced for gender. Durational measures of utterances were analyzed in syllables and phones per second in both spontaneous and imitated speech contexts. The articulation rate of the 5-year-old subjects was significantly faster than that of the 3-year-olds. Spontaneous speech was significantly faster and more variable than imitated speech. Some gender differences were found. Measures in syllables per second and phones per second, although not always yielding identical results, were found to be highly correlated.

Age Factors↗
PubMed1991

Long-term safety and efficacy profile of simvastatin.

Simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, has been administered to approximately 2,400 patients with primary hypercholesterolemia with a mean follow-up of 1 year in controlled clinical studies and their open extensions. Approximately 10% of this population received simvastatin for a period of greater than or equal to 2 years. The population on whom this safety analysis is based had a mean age of 50 years; 62% were men and approximately 27% had preexisting coronary artery disease. Simvastatin was titrated to the maximal daily dose of 40 mg each evening in 56% of the study population (last recorded dose). The most frequently reported drug-related clinical adverse experiences were constipation (2.5%), abdominal pain (2.2%), flatulence (2.0%) and headaches (1%). Persistent elevations of serum transaminase levels greater than 3 times the upper limit of normal were observed in only 1% of this cohort with only 0.1% of the total population requiring discontinuation of therapy. There were no clinically apparent episodes of hepatitis. Discontinuation of therapy due to myopathy was extremely rare (0.08%). Only minimal increases in the frequency of lens opacities (1%) were observed from baseline to the last lens examination during follow-up, consistent with the expected increase in lens opacity development due to normal aging. Patients who were greater than or equal to 65 years old had a clinical and laboratory safety profile comparable to the nonelderly population.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

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