Scholastic ability versus attitude, time, and performance on programmed instruction.
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Aptitude↗
Biomedical subjects
W R Clarke
Publications and source records attributed to W R Clarke.
Villous adenoma with hypokalemia.
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Adenoma↗
A longitudinal view of blood pressure during childhood: the Muscatine Study.
Four thousand three hundred and thirteen children beginning at five to fourteen years of age have been examined on three to six occasions in Muscatine, Iowa, on alternate years. To compare blood pressures throughout the period of observation each value was expressed as a percentile rank. For each subject the average percentile rank (level), the trend in rank and the variability over time were calculated. Values for height, weight, relative weight and triceps skinfold thickness measurements were expressed in the same fashion. There is a relationship between average rank of blood pressure and average rank of body size as well as between trend of blood pressure and trend of body size percentiles. These observations indicate the importance of relative rate of growth in the establishment of the rank order of blood pressure during childhood.
Adolescent↗
The transitional circulation: physiology and anesthetic implications.
Over the past decade, several aspects of the physiology of the transitional circulation have been elucidated. The transitional circulation may be viewed as a process divided into four phases. The concept of these phases underscores the fact that the normal transitional circulation should be viewed as an orderly process and not a single event. Within these phases, several mechanisms seem to be involved in the control of pulmonary vascular resistance (PVR). Yet even these mechanisms do not completely explain the process of the normal transition, and very little is understood about why the transition occasionally fails. No doubt other as yet undescribed mechanisms also play a role. Much work remains to be done in the study of the normal and abnormal transitional circulation. The profound hypoxia that characterizes infants with failed transitional circulation from any cause is due to a persistently high PVR, causing right-to-left shunting at the ductal and foramental levels. Clinical care of these infants is based on efforts to simultaneously decrease PVR and increase systemic vascular resistance (SVR). Appropriate measures include the use of supplemental oxygen, hyperventilation, alkalinization, and sedation to decrease PVR and intravenous (IV) fluids and pressors to increase SVR. The rapidly fluctuating nature of the physiologic processes that cause failure of the transitional circulation must be kept in mind when caring for these infants, both during initial stabilization in the delivery room and while administering anesthesia for surgical repair of congenital defects.
Anesthesia, General↗
Lead exposure among workers renovating a previously deleaded bridge: comparison of trades, work tasks.
Airborne and surface lead exposures were evaluated for construction trade groups at a previously deleaded bridge renovation site in the midwestern United States. Although all lead-based paint should have been removed, old layers of leaded paint were still present on some sections of the bridge. Ironworkers performing metal torch cutting had the highest exposures (188 microg/m3), followed by workers engaged in clean-up operations and paint removal (p < 0.001). Respirators were most frequently worn by workers with the greatest lead exposures; however, laborers performing clean-up operations had exposures to lead dust of 43 microg/m3 and often wore no respiratory protection. Wipe samples revealed that almost all contractor vehicles were contaminated with lead. Heavy equipment operators with low airborne lead exposure had the highest levels of surface contamination in personal vehicles (3,600 microg/m2). Laborers cleaning structural steel with compressed air and ironworkers exposed to lead fumes from cutting had the highest concentrations of lead dust on clothing (mean 4,766 microg/m2). Handwashing facilities were provided, but were infrequently used. No separate clothes changing facility was available at the site. The potential for "take-home" contamination was high, even though this site was thought to be relatively free of lead. Construction contractors and their workers need to be aware that previous deleading of a site may not preclude exposure to significant amounts of lead.
Air Pollutants, Occupational↗
Self-reported postwar injuries among Gulf War veterans.
OBJECTIVE: From September 1995 to May 1996, the authors conducted a telephone survey of Iowa military personnel who had served in the regular military or activated National Guard or Reserve during the Gulf War period. To assess the association between military service in a combat zone and subsequent traumatic injury requiring medical consultation, the authors analyzed veterans' interview responses. METHODS: Using data from the larger survey, the authors compared rates of self-reported postwar injuries requiring medical consultation in a sample of Iowa Gulf War veterans to the rates in a sample of Iowa military personnel who served at the same time, but not in the Persian Gulf. RESULTS: Of 3695 veterans, 605 (16%) reported a traumatic injury in the previous three months requiring medical consultation. Self-reported injuries were associated with service in the Persian Gulf (odds ratio 1.26; 95% confidence interval 1.02, 1.55). CONCLUSION: This finding is consistent with the results of earlier studies of traumatic injury mortality rates among war veterans.
Adult↗
Left ventricular hypertrophy in children with blood pressures in the upper quintile of the distribution. The Muscatine Study.
From echocardiography measurements of left heart dimensions, cardiac output was estimated in 264 school children whose systolic blood pressure persisted in the lowest, middle, or highest quintile of the distribution for their age and sex. Children with blood pressure in the upper quintile were taller, heavier, and more obese. Echocardiographically determined left ventricular wall mass, corrected for body size, was significantly greater in these children than those in the lower quintiles of blood pressure. These children displayed a continuum of cardiac output. Those with the highest cardiac output in the upper blood pressure quintile had the greatest left ventricular wall mass.
Adolescent↗
The cardiovascular responses to exercise in children across the blood pressure distribution. The Muscatine study.
Children with elevated systolic blood pressure have a wide range of cardiac output. To better understand the mechanisms regulating resting and exercise blood pressure, we investigated the cardiovascular responses to both dynamic and isometric exercise in 264 children who were selected from the low, middle, and upper quintile of the distribution of blood pressure of an entire school population. We sought to identify patterns of response to exercise that correlated with both resting cardiac output and resting blood pressure. During isometric exercise, systolic pressure adjusted for age and body size increased in all groups. The low group's mean pressure remained significantly lower than the high group's pressure throughout the entire exercise period. Body size adjusted group systolic and diastolic blood pressure level differences exist during dynamic exercise. The product of the systolic blood pressure times the heart rate, in the high blood pressure group, was significantly higher throughout dynamic exercise than in the other two groups. Elevated resting resistance is correlated with elevated resistance during isometric exercise and elevated diastolic blood pressure during dynamic exercise. Cardiac index had a significant negative correlation to age (r = -0.58) at all levels of blood pressure. This observation, in children, lends some support to the concept of the evolution from a hyperkinetic circulation in early childhood to a circulation with lower cardiac output and more elevated systemic vascular resistance at an older age.
Adolescent↗
Potentially serious drug interactions secondary to high-dose diltiazem used in the treatment of pulmonary hypertension.
Two patients had potentially serious drug interactions (phenytoin, digoxin) that were probably attributable to changes in pharmacokinetics and pharmacodynamics caused by high-dose calcium channel blocker therapy (diltiazem) in the treatment of pulmonary hypertension. Even in the approved normal dosages for the treatment of angina and hypertension, calcium channel blockers are known to cause significant changes in the metabolism of other drugs. Currently, no data exist on the effects of the very high dosages of these drugs, administered to patients with pulmonary hypertension, on the metabolism and clearance of other agents, although, based on our experience and literature reports, recommendations for monitoring therapy can be made.
Adolescent↗
Obesity in childhood: the Muscatine Study.
Beginning in 1971 children in grades kindergarten through the 12th grade were examined on alternate years until 1992 in Muscatine, Iowa, in these examinations the following variables were assessed: height, weight, skinfold thickness, lipids, lipoproteins, smoking behaviors, as well other variables. In order to lend relevance to risk factors in childhood a number strategies have been used. These include: 1) Examination of familial aggregation and mortality; 2) Segregation analysis of genetic mechanisms; 3) Relationship of obesity in childhood to other established risk factors; 4) Examination of the relationship of childhood obesity to the development of coronary artery calcification as assessed by electron beam computed tomography. In these studies we have shown that obese children's siblings, mothers, fathers, aunts and uncles have significant greater body mass indices than leaner children. Children who are obese have significantly higher systolic and diastolic blood pressure, higher plasma triglycerides and lower HDL-cholesterol levels. The first and second degree relatives of obese hypertensive children have a higher mortality rate from cardiovascular disease than leaner children's relatives. From complex segregation analyses about 35% of the population of Muscatine appear to carry a gene for obesity and 6% appear homozygous. Over the past decade we have observed that the children in Muscatine, Iowa have become more obese than previously. Our longitudinal observations indicate that obesity acquired in childhood is predictive of adult obesity and is also predictive of the development of coronary artery calcification. Thus obesity in childhood is not only an important risk factor in children but also a growing public health problem for children and adolescents.
Adolescent↗