Biomedical subjects

W C Bevier

Publications and source records attributed to W C Bevier.

8 recordsLinked to original sources

PubMed1995

Fasting plasma glucose and glycosylated plasma protein at 24 to 28 weeks of gestation predict macrosomia in the general obstetric population.

The purpose of this study was to modify the traditional gestational diabetes screening process in order to provide a test that might more reliably detect those women at risk of delivering a macrosomic infant despite a negative test for gestational diabetes mellitus (GDM). Pregnant women (n = 160) were screened for GDM at 24 to 28 weeks' gestation using the traditional 50 g glucose challenge test (GCT). In addition, glycosylated hemoglobin, glycosylated serum protein, and glycosylated plasma protein (GPP) were analyzed from blood drawn at this same time. If the patient's challenge test was positive (140 mg/dL or higher), a 100 g oral glucose tolerance test (OGTT) was performed. Twenty-three women had a positive GCT (14.4%) and five (3.13%) were excluded from further study because they received treatment for gestational diabetes based on a positive OGTT. None of the GCT-negative or the GCT-positive-OGTT-negative patients received treatment. Gestational age at delivery, infant gender, and birthweight were retrieved from birth records. Although several correlations with infant birthweight were found, the fasting plasma glucose (FPG) and GPPs proved most significant. The FPG on the OGTT significantly correlated with infant birthweight (p < 0.001; r = 0.94). A value greater than 90 mg/dL proved to be 100% sensitive and 64% specific for infant birthweight more than 4000 g. The relationship of the GPP and subsequent infant birthweight was also significant (p < 0.001; r = 0.81). A GPP greater than 23% proved to be 100% sensitive in predicting birthweight above 4000 g (11 of 11 infants); however, the test had a 52% specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗

PubMed1995

Pancreatic disorders of pregnancy. Diagnosis, management, and outcome of gestational diabetes.

Gestational diabetes is one of the more common medical problems of pregnancy. This article reviews the literature regarding the diagnosis and treatment and the controversy that surrounds gestational diabetes. The need for stricter guidelines for diagnosis and treatment and the evidence supporting this need are presented. Long-term follow-up evaluation for women with gestational diabetes and for their children is discussed.

Diabetes, Gestational↗

PubMed1990

Systematic 24-hr behavioral observations of sleep and wakefulness in a skilled-care nursing facility.

Sleep patterns of aged, infirm, demented, chronically institutionalized residents of a skilled-care nursing facility were studied. The purpose of this naturalistic study was to describe sleep and wakefulness (S/W) within the limits afforded by brief behavioral observations and to examine homeostasis and diurnal rhythmicity of S/W as a function of psychoactive drug intake. Observers noted S/W every 15 min, 24 hr a day for 10 days in 24 Ss. Results indicated substantial individual variation in daytime hours. Daily and weekly variation within Ss was minimal. Sleep was least likely near sunset. Ss on psychoactive drugs showed dampened diurnal variation in S/W rhythms. In Ss not on such drugs, there was a suggestion of homeostasis of S/W between sleep during the morning and evening hours. Results are discussed methodologically (viability of approach), theoretically (age-related change in sleep), and practically (potential treatments).

Aged↗

PubMed1989

Relationship of body composition, muscle strength, and aerobic capacity to bone mineral density in older men and women.

We evaluated the relationship of body composition, maximal aerobic capacity (VO2max), and muscle strength to bone mineral density in 91 healthy men and women, age 61-84 years. Lean body mass was estimated from two independent measures of fat mass, bioelectrical impedance and skinfold thickness. VO2max was determined by treadmill ergometry with direct measurement of oxygen consumption. Grip and back strength were measured by isometric dynamometry. Mineral density of lumbar spine and midradius were measured by dual- and single-photon absorptiometry. Men had significantly greater lean mass, muscle strength, aerobic capacity, and bone density than women. In women, grip strength correlated with forearm and spine density (r = 0.37, r = 0.28, p less than 0.05). In men, grip strength correlated with forearm density (r = 0.47, p less than 0.05), and back strength was significantly correlated with both spine (r = 0.46, p less than 0.01) and forearm density (r = 0.46, p less than 0.01). In women, neither forearm nor spine density correlated significantly with aerobic capacity. In men, midradius density did not correlate significantly with oxygen consumption, but the simple correlation between spine density and VO2max was significant (r = 0.41, p less than 0.05). Back strength and VO2max were significantly related in men (r = 0.47, p less than 0.01). By stepwise multiple regression, back strength emerged as the most robust predictor of spine mineral, accounting for 19% of the variation in bone density. Addition of VO2max to the regression did not add significant predictive value. However, when VO2max was expressed per kilogram lean body mass, both back strength and VO2max contributed significantly to the prediction of spine density in men, and the coefficient of determination R2 increased to 0.30. We conclude that body mass and grip strength, but not aerobic capacity, significantly predict bone density in elderly women. In elderly men, back strength is a more robust predictor of axial bone density than traditional expressions of aerobic capacity, but VO2max per kilogram lean mass and back strength both make significant contributions to the prediction of spine mineral density. The applicability of these results to younger men and women is uncertain.

Aged↗

PubMed1987

Cardiovascular function during sleep of active older adults and the effects of exercise.

Cardiovascular function during sleep was studied in 14 (6 males, 8 females) healthy, active, older adults (57-70) years). Noninvasive measures of stroke volume (SV), heart rate (HR), cardiac output (CO), pre-ejection period (PEP), and left ventricular ejection time (LVET) were taken using impedance cardiography and computer-based "ensemble" averaging. Data were obtained from the last of three nights of normal sleep and on a night following an hour walk on a treadmill at 60% VO2 max. Cardiovascular measures revealed patterns during sleep which parallel those seen in younger subjects, i.e. a progressive decline in SV and CO, unaffected by EEG sleep stage. The trend was different for heart rate, which showed only an initial decline at sleep onset. No consistent trends were seen for LVET, whereas PEP declined to a low point 1.5 h after sleep onset. Following exercise, HR was slightly elevated during the first 3 h of sleep. In contrast, SV and CO were reduced during the period of sleep between 1 and 4 h after sleep onset; this difference was observed primarily in the women (N = 8). The results suggest that an acute increase in daily activity of older adults induces only minor changes in nocturnal cardiac function.

Aged↗

PubMed1985

Effects of exhaustive submaximal exercise on cardiovascular function during sleep.

The influence of an afternoon bout of exhaustive submaximal exercise on cardiovascular function and catecholamine excretion during sleep was examined in five female and four male subjects. Subjects walked on a treadmill for successive 50-min periods at 50, 60, and 70% maximal O2 consumption, separated by 10-min rest periods. Exercise terminated with volitional exhaustion. Following an adaptation night, electroencephalographic and impedance cardiographic measures were obtained during three successive nights of sleep, with exercise preceding night 3. Relative to the base-line night (night 2), exhaustive exercise resulted in a sustained elevation of heart rate and cardiac output throughout the entire night's sleep. The magnitude of these elevations was unaffected by sleep stage but decreased over the night. The typical pattern of circadian decline in cardiac output was unaltered. However, the decline in heart rate with sleep onset was greater on the exercise night. Changes in impedance dZ/dt and R-Z interval suggested an enhanced myocardial contractility during the first 3 h of sleep postexercise. Analysis of morning urine samples revealed that in seven of nine subjects norepinephrine excretion increased, epinephrine excretion decreased, and dopamine excretion was unchanged during sleep on the exercise night. It is suggested that these cardiac changes reflect a sustained increase in myocardial beta-receptor activity.

Adult↗

PubMed1984

Sleep interruption and exercise.

Five men and five women participated in a study comparing the effects of sleep interruption with and without the imposition of physical activity. Subjects were awakened following the second REM period and returned to sleep 1 h later. In the IS condition they sat up and read during this period; in the ISE condition they exercised for 50 min at 60% VO2max. Relative to undisturbed sleep (US), IS resulted in a substantially shortened third non-REM (NREM) period, increased eye movement (EM) duration and density in the third REM period, and increased slow-wave sleep (SWS) in the fourth NREM period. The loss of delta sleep in the shortened NREM period was compensated for by an increase in delta sleep in the fourth NREM period (r = -0.90). However, total SWS obtained after interruption was unchanged from US. The ISE condition induced increases in cardiac output and temperature during sleep. No consistent changes in SWS were observed relative to IS, but the duration of the third REM period was reduced as well as EM duration and density within that REM period. Since REM sleep propensity is typically highest during the metabolic nadir of early morning sleep, the suppression of tonic and phasic components of REM sleep after ISE was concluded to result from the exercise-induced increase of metabolism and body temperature during sleep.

Adult↗

PubMed1983

Nocturnal sleep, cardiovascular function, and adrenal activity following maximum-capacity exercise.

Eight subjects performed a treadmill test of their maximal aerobic capacity (VO2max) to determine whether exercise which is maximally stressful but relatively low in total energy expenditure may affect nocturnal sleep. The test was performed at 16.00 h on day 3 of the study, with day 1 as adaptation, day 2 as baseline and day 4 as a carryover night. Changes observed after exercise included a decrease in the duration of the first REM sleep period, an elevation of heart rate in the first 2 h of sleep, a reduction in norepinephrine excretion and an increased excretion of dopamine. Comparisons of sleep alterations in 4 subjects who exercised regularly (active group) with 4 subjects who took no regular exercise revealed differences in the first sleep cycle. Active subjects displayed an increased duration of SWS coupled with an increased latency to first REM onset. Non-active subjects, by contrast, displayed a shortened REM latency and duration of SWS. These results indicate that short-term maximum exercise may induce significant alteration of the temporal distribution of SWS with differences in response seen between regular exercisers and non-exercisers.

Adrenal Glands↗