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Biomedical subjects

G W Somes

Publications and source records attributed to G W Somes.

At least 37 records · Page 2Linked to original sources
PubMed1993

Ambulatory blood pressure patterns in youth.

We examined the influence of sex, race, and age on ambulatory blood pressure (BP) patterns in youths. The subjects were 300 normotensive, healthy adolescents between the ages of 10 and 18 years, including 160 boys and 140 girls, of whom 149 were white and 151 were black. The data were divided into periods of activity (Period I: 8 AM to 10 PM) and inactivity (Period II: 10 PM to 8 AM). Boys had higher systolic BP during both Period I (117 +/- 11 nu 112 +/- 8 mm Hg; P < .05) and Period II (109 +/- 11 nu 106 +/- 10 mm Hg; P < .03). Blacks had higher systolic (108 +/- 10 nu 106 +/- 10 mm Hg; P < .01) and diastolic BP (63 +/- 8 nu 60 +/- 7 mm Hg; P < .003) during Period II. Interactions between race and age were found for both systolic (P < .005) and diastolic (P < .005) BP during Period II. Further analyses indicated associations between age and both systolic (beta = 1.16; P < .001) and diastolic (beta = 1.04; P < .0001) BP in black but not white subjects. An interaction was observed between sex and age for systolic BP during Period II (P < .005), with a relationship for boys (beta = 1.47; P < .001) but not for girls. These results suggest that the black adolescents showed a progressive increase in nocturnal BP with age, a pattern not observed in the white youths. This increased BP load may contribute to the early development of hypertension and BP-induced target organ damage in blacks.

Adolescent↗
PubMed1992

Long-term ictal monitoring with subdural strip electrodes: prognostic factors for selecting temporal lobectomy candidates.

Long-term electrocorticographic (ECoG) monitoring data from subdural strip electrodes are analyzed to determine factors associated with seizure-free outcome from anterior temporal lobectomy. A total of 89 consecutive patients with complex partial seizures, in whom long-term ictal video/scalp electroencephalographic monitoring was insufficient to localize their epileptogenic focus, were subsequently evaluated with long-term ictal ECoG monitoring using subdural strip electrodes. Each patient underwent anterior temporal lobectomy based on the ictal ECoG data and has been followed for at least 1 year. The following parameters were found to be statistically significant in predicting a seizure-free outcome: unilateral onset, electrical onset pattern beginning as fast spike trains, absence of frontal lobe background desynchronization at onset, and an interhemispheric propagation time of greater than 8 seconds. Electrocorticographic criteria that were not associated with seizure outcome included: right- versus left-sided onset, time from electrical to clinical ictal onset, focality of onset (number of strip electrode contacts involved), and stereotypical ECoG onset. When present, the interictal focus was concordant with the ictal focus in most patients (96%), but was falsely lateralizing in 4% of cases. It is suggested that these data should improve patient selection for temporal lobectomy when subdural strip monitoring is used during preoperative evaluation.

Adolescent↗
PubMed1991

Determining efficacy of monitoring devices: evaluating new technologies.

We point out the connection between electronic monitoring and repeated screening tests, and suggest a flexible and practical method to determine the efficacy of monitoring devices and new technologies. We point out the benefits of the Mantel-Haenszel estimator of an odds ratio for determining diagnostic test indices. From estimates of sensitivities and specificities, we produce receiver operating characteristic (ROC) curves to compare the performance of two or more monitoring devices in a clinical setting.

Algorithms↗
PubMed1991

Sodium excretion and racial differences in ambulatory blood pressure patterns.

The influence of Na+ excretion and race on casual blood pressure and ambulatory blood pressure patterns was examined in a biracial sample of healthy, normotensive children and adolescents (10-18 years; n = 140). The slopes relating 24-hour urinary Na+ excretion to systolic blood pressure were different for both black and white subjects for casual blood pressure (p less than 0.001) and blood pressure during sleep (p less than 0.03). For casual blood pressure, the slope was significant for black subjects (beta = 0.17; p less than 0.001) but not for white subjects. For blood pressure during sleep, the slope was again significant for black subjects (beta = 0.08; p less than 0.01) but not for white subjects. Na+ excretion was also related to awake levels of systolic blood pressure for black subjects (beta = 0.08, r = 0.36; p less than 0.01), although the slopes for both black and white subjects were not significantly different. Further analyses indicated the results were not due to racial differences in 24-hour urinary K+ excretion. However, plasma renin activity was marginally related to Na+ excretion in white subjects (r = 0.22; p less than 0.06) but not black subjects, a finding that is consistent with previous studies. Na+ excretion was not associated with diastolic blood pressure or heart rate in either group under any condition. The results of this study support research that has demonstrated a stronger relation between Na+ handling and casual blood pressure in black subjects and extend these findings to blood pressure while the subject is both awake and asleep.

Adolescent↗
PubMed1991

Ambulatory blood pressure patterns in children and adolescents: influence of renin-sodium profiles.

A renin-sodium nomogram for normotensive children and adolescents was developed at our institution. The ambulatory blood pressure patterns of subjects classified by the nomogram were then compared. A biracial sample of 159 children and adolescents were classified as having a low, intermediate, or high renin-sodium profile based on the relationship between their plasma renin activity and 24-hour urinary sodium excretion. Casual (106/58 vs 107/61 vs 106/62 mm Hg) and awake (116/69 vs 117/69 vs 116/70 mm Hg) blood pressure values were comparable among subjects with low, intermediate, and high renin-sodium profiles. Subjects with high renin-sodium profiles, however, had a smaller decline in systolic blood pressure with sleep than did subjects with low renin-sodium profiles (7 vs 11 mm Hg; P less than .04), and higher diastolic blood pressure readings during sleep than subjects with intermediate renin-sodium profiles (65 vs 62 mm Hg; P less than .05). Subjects with high renin-sodium profiles also had greater variance of diastolic blood pressure readings during sleep than either subjects with low renin-sodium profiles (P less than .01) or those with intermediate renin-sodium profiles (P less than .02). The blunted nocturnal decline and increased nocturnal variance of blood pressure among subjects with high renin-sodium profiles may be a marker or mechanism for the future development of essential hypertension.

Adolescent↗
PubMed1990

Coffee consumption and serum lipids: a randomized, crossover clinical trial.

PURPOSE: The purpose of this study was to determine the effect of consuming three or more cups of filter-brewed coffee per day on levels of serum lipids. SUBJECTS AND METHODS: A prospective, randomized crossover clinical trial was performed. Twenty-one healthy white male subjects completed the trial, and consumed an average of 3.6 cups of coffee a day. Data were evaluated by analysis of variance for repeated measures and t-test for paired means. RESULTS: No effect of coffee consumption on serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or apolipoprotein B was found. Diet, creamer use, and cigarette use as well as group assignment and time factors were controlled for in the analysis. CONCLUSION: We found no effect of moderate consumption of filter-brewed coffee on serum levels of atherogenic lipids. This study supports previous work that filtered coffee has no adverse effect on serum lipids. This has far-reaching implications given the widespread use of coffee and the current concern over coronary risk factors.

Adult↗
PubMed1990

Frequent handling in the neonatal intensive care unit and intraventricular hemorrhage.

The association between periventricular-intraventricular hemorrhage (PV-IVH) and frequent handling resulting from various neonatal intensive care procedures and routine interventions was evaluated in a prospective clinical study. Inborn premature babies with birth weight less than or equal to 1500 gm (n = 156) who did not have PV-IVH or who had grade 1 PV-IVH at less than or equal to 1 hour were randomly assigned to the reduced manipulation protocol (n = 62) or to standard care (n = 94). A bedside microcomputer-based data acquisition system was used to monitor the duration of rest or the number of interventions per day. Infants assigned to receive reduced manipulation spent a significantly higher percentage of time each day at rest than did those who received standard manipulation (p less than 0.006). However, the incidence of grades 2 to 4 PV-IVH did not differ significantly (30% in the study vs 37% in the standard manipulation group). When we analyzed the effect of manipulation in relation to risk of PV-IVH, while taking into account other perinatal variables, standard manipulation was not associated with increased risk of grades 2 to 4 PV-IVH. However, low birth weight, maternal smoking, general anesthesia, early grade 1 PV-IVH, low hematocrit, lowest arterial oxygen pressure within the first 6 hours of life, and large base deficit at 6 hours of age all increased the relative risk of grades 2 to 4 PV-IVH.

Cerebral Hemorrhage↗
PubMed1990

Mean arterial blood pressure changes in premature infants and those at risk for intraventricular hemorrhage.

Bedside microcomputer-derived, minute-to-minute mean arterial pressure (MAP) values during the first 48 hours of life were studied in 100 preterm babies with birth weight less than or equal to 1500 gm. In those babies (n = 72) with no periventricular-intraventricular hemorrhage (PV-IVH) or with grade 1 PV-IVH, the MAP values increased during the study period, with minute-to-minute variation and interval undulation. The MAP values in those with birth weight greater than 1000 gm were higher than in those of lower birth weight. Infants in whom grades 2 to 4 PV-IVH developed (n = 28) had consistently lower MAP values during the study period. Minute-to-minute variability, expressed as the average of the coefficients of variation at 15-minute intervals, did not differ between birth weight groups, nor did they differ between the PV-IVH group and their matched control subjects. However, those with PV-IVH spent a greater percentage of time, with a coefficient of variation greater than or equal to 13% or less than 3%, than their matched control subjects spent (p less than 0.005). This study provides reference data for MAP changes in premature babies. The observed MAP changes in those with PV-IVH lend support to a significant role for MAP alterations in the pathogenesis of PV-IVH.

Blood Pressure↗
PubMed1990

Aerobic fitness and the diurnal rhythm of blood pressure in adolescents.

We examined the effects of aerobic fitness and race on the diurnal rhythm of blood pressure of 175 healthy adolescents who performed a cycle ergometer maximal exercise test while oxygen consumption was measured. A median split of maximum oxygen consumption for boys and girls separately classified them as either "more-fit" or "less-fit" subjects. Ambulatory blood pressure recordings were also performed, and the data were analyzed for means while subjects were awake and asleep. Less-fit black boys had higher systolic pressures than more-fit black boys while awake (124 vs. 115 mm Hg; p less than 0.009) and asleep (117 vs. 108; p less than 0.001). Less-fit black boys also had higher systolic pressures than less-fit white boys while awake (114; p less than 0.002) and asleep (105; p less than 0.001), and they had higher systolic pressures than more-fit white boys while asleep (105; p less than 0.01). Less-fit black girls had higher systolic pressures than more-fit black girls while awake (116 vs. 109; p less than 0.004) and asleep (109 vs. 100; p less than 0.001). Less-fit black girls also had higher diastolic pressures than more-fit black girls while awake (71 vs. 66; p less than 0.002) and asleep (66 vs. 61; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

The accuracy of self-reports of physical activity.

This investigation determined the accuracy of self-reports of physical activity compared to observations obtained surreptitiously. Subjects were 44 adults engaged in 1 h of their preferred physical activity while actual activity levels were surreptitiously obtained and compared to immediate self-reported estimates of physical activity. Results indicated that subjects were moderately accurate in recalling their physical activity levels (R = 0.62) but underestimated sedentary activities and overestimated aerobic activities by over 300%. Males overestimated their activity relative to females, and obese subjects underestimated their activity levels compared to normal-weight subjects. Finally, a number of two-way interactions that moderated the accuracy of those subjects engaging in high chronic levels of physical activity were observed.

Adult↗
PubMed1989

Race and gender influence ambulatory blood pressure patterns of adolescents.

The purpose of this study was to examine ambulatory blood pressure and heart rate patterns in healthy, normotensive adolescents and to determine the influence of race and gender on these patterns. Ambulatory blood pressure recordings were performed on 199 adolescents; 42 were black males, 55 were white males, 65 were black females, and 37 were white females. The mean age (+/- SD) was 13 +/- 2 years. Blood pressure readings were obtained with an automatic, noninvasive recorder. Black adolescents and white adolescents had similar blood pressures while awake (116/69 vs. 116/69 mm Hg), with boys having higher levels of systolic blood pressure (118 vs. 114 mm Hg) and comparable levels of diastolic blood pressure (69 vs. 69 mm Hg) relative to girls. The patterns while the adolescents were asleep, however, were different. White boys (106 mm Hg), white girls (105 mm Hg), and black girls (105 mm Hg) had similar systolic blood pressures during sleep. Black boys (112 mm Hg), however, had significantly higher systolic blood pressures while asleep. Black adolescents, as a group, had significantly higher diastolic blood pressures than white adolescents while asleep (64 vs. 61 mm Hg). Changes in blood pressure from awake to asleep were not related to changes in heart rate. Results of this study indicate that both race and gender are important determinants of the diurnal pattern of blood pressure and heart rate in adolescents.

Adolescent↗
PubMed1986

Estrogens and progesterone during gestation in Dolichotis patagona.

During pregnancy, a progesterone-binding plasma protein is present and is similar in several respects to the binding protein reported in other hystricomorphs. These findings establish estradiol-17 beta as the predominant estrogen of pregnancy and that progesterone rises during pregnancy and does not decline until after parturition. Gestation length is 96 days. This study establishes similarities between the mara and its closest relative, the guinea pig.

Alpha-Globulins↗
PubMed1986

Excretory urography with iohexol: evaluation in children.

A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.

Adolescent↗
PubMed1986

Race and cardiovascular reactivity. A neglected relationship.

The magnitude of the cardiovascular response to stress has been implicated in the pathogenesis of cardiovascular disease. Psychological stress procedures have received increased usage as an alternative to expensive physical (exercise) stress procedures. In the present investigation, 213 healthy, black or white, male or female children between the ages of 6 and 18 years were exposed to the psychological stress of a video game. The video game challenge was administered by a black or a white experimenter and was played under three levels of increasing stress, 1) personal challenge, 2) experimenter's challenge, and 3) experimenter's challenge accompanied by a financial incentive, while blood pressure and heart rate were monitored. Results indicated that the video games provoked significant and incremental cardiovascular reactivity across the games. Black children demonstrated significantly greater reactivity than white children; the racial difference was more reliably observed for systolic and diastolic blood pressure than for heart rate. Furthermore, the race of the experimenter exerted a significant effect and often interacted with the race of the child, such that greater reactivity occurred in same-race pairings than in mixed-race pairings. These results suggest that reactivity is affected by an individual's race and social milieu and that reactivity may be one mechanism responsible for the greater prevalence of hypertension among blacks.

Adolescent↗
PubMed1984

Patient response to variations in denture techniques. Part VI: Mastication of peanuts and carrots.

This 5-year study was designed to determine if differences in masticatory ability existed among patients for whom dentures had been prepared with two different techniques. Patients were instructed to chew a given amount of a reliable test food for a certain number of strokes on each side of the mouth. After each trial the food was collected into a No. 8 mesh screen, washed, dried, and weighed. The percentage weight of food masticated per side per patient was recorded for each year. Results were combined for each group results and analyzed statistically. Statistical analysis of the two groups revealed changes in masticatory ability over the 5-year period. However, no significant statistical differences in masticatory ability existed between the two groups.

Arachis↗
PubMed1984

The influence of a supportive, problem-solving, group intervention on the health status of students with great recent life change.

A small randomized trial was conducted with college students to test the efficacy of a supportive, problem-solving group intervention for reducing morbidity following accumulation of numerous life changes. The two intervention groups reported declines in number of illness episodes and number of disability days over the two semesters of study; one of the intervention groups also reported a decrease in number of days on which illness was experienced. The control group did significantly worse on these measures than the intervention groups.

Clinical Trials as Topic↗