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Biomedical subjects

F W James

Publications and source records attributed to F W James.

At least 19 recordsLinked to original sources
PubMed1999

Sex and race differences in cardiovascular disease risk factor changes in schoolchildren, 1975-1990: the Princeton School Study.

OBJECTIVES: This study was done to assess changes in obesity and risk factors for cardiovascular disease (CVD) in Black and White children from 1975 through 1990. METHODS: A cross-sectional study of body composition and CVD risk factors conducted in a school district as part of the Lipid Research Clinics (LRC) Program Prevalence Study (1973-1975) was compared with a later study (1989-1990) conducted in the same school district, which remained demographically stable. The studies included 1456 third- and fifth-grade students and 300 LRC subjects within the same age ranges. RESULTS: Students in the 1989-1990 study had a significantly higher mean body mass index (BMI), total blood cholesterol concentration, and systolic and diastolic blood pressures and marginally higher resting heart rates than those in the earlier study. The prevalence of obesity increased from 12.5% to 25.3%, and of hypercholesterolemia from 8.0% to 14.8%. Black females had the largest increase in BMI and resting heart rate and the highest prevalence of elevated total cholesterol in the 1989-1990 study. CONCLUSIONS: The results of this study suggest a secular trend toward increased obesity in children and portend the potential development of a public health problem that could reverse the recent decline in morbidity from CVD.

Adolescent↗
PubMed1990

[Cycloergometric exercise test in normal children: comparison of an Italian and a North American population].

The need for a more complete protocol for bicycle ergometer exercise testing in children in our country, induced the Authors to apply the F.W. James protocol to healthy Italian children and then compare the results with a study on a similar american sample population. A total of 102 children, 67 males and 35 females, age range 4.4 - 17 years (mean 10.3 yrs), were examined following the F.W. James protocol. The Authors report the anthropometric and ergometric data obtained, the comparison with James' results and the linear correlation coefficients. Normal reference data were obtained. There were no significant differences between the results obtained from the Italian and American groups, and the correlation coefficients were satisfactory. The results will enable us to benefit from a simple and complete protocol which can be applied to healthy and sick children alike in our country.

Adolescent↗
PubMed1989

Azelastine effects on electrical and mechanical activities of guinea pig papillary muscles.

The effects of azelastine, a new anti-asthmatic drug under clinical investigation, were studied on both normal fast action potentials (APs) and slow APs using conventional microelectrode techniques in guinea pig papillary muscles (superfused with oxygenated Tyrode solution at 37 degrees C). Slow APs were induced by either 10(-7) M isoproterenol, 10(-5) M histamine, db-cAMP (3 mM) or 10 mM TEA, in the presence of 25 mM [K]o to voltage inactive the fast Na+ channels. At 10(-5) M, azelastine depressed the maximum rate of rise (+Vmax) of the slow APs and the force of contraction. At 3 X 10(-5) M, azelastine further reduced +Vmax and the amplitude of the slow APs; complete abolishing of slow APs and contractions occurred at 10(-4) M. Upon washout of the drug, automaticity appeared. In the presence of 10(-4) M azelastine, increasing the [Ca]o concentration from 1.8 to 3.6 and 5.4 mM caused partial recovery of the slow APs and contractions. The fast APs were also depressed by azelastine. At 10(-5) and 3 X 10(-5) M, azelastine reduced +Vmax and the AP duration at 50% repolarization (APD50) of the fast APs. Complete block of the fast APs and suppression of contractions were observed after 30 min at 10(-4) M azelastine. After 3-5 h of washout, excitability recovered; however, +Vmax was depressed and APD90 was prolonged. It is concluded that azelastine inhibits the slow Ca2+ channels and the fast Na+ channels. The slow recovery suggests that the drug may accumulate inside the cells, and exert a prolonged inhibitory effect on contraction.

Action Potentials↗
PubMed1989

Hemodynamic response to exercise in patients with sickle cell anemia.

In order to evaluate potential electrocardiographic (ECG) correlates of ST-segment depression during exercise in patients with sickle cell anemia (SS), 43 subjects, aged 5-23 years, underwent submaximal exercise testing. Eight (19%) had ST-segment depression on the exercise ECG during submaximal exercise. These eight patients had significantly lower hemoglobin levels than the 35 subjects without evidence of ST-segment depression. These eight subjects also had significantly higher peak blood pressures and peak heart rates than the 35 subjects without ST-segment depression. The product of peak heart rate and peak systolic blood pressure, the maximal double product, is a correlate of myocardial oxygen consumption and was significantly higher in the patients with ST-segment depression than in the patients without ST-segment depression. These results indicate that patients with SS and evidence of exercise-induced ST-segment depression may have decreased myocardial oxygen supply due to low hemoglobin levels and increased myocardial oxygen demand (elevated double products) when compared to subjects with SS who do not have exercise-induced ST-segment depression.

Adolescent↗
PubMed1989

Blood pressure and cardiac output during exercise: a longitudinal study of children undergoing repair of coarctation.

Data were examined from 21 children who underwent graded exercise studies prior to and within 5 years after repair of coarctation. A control group of 10 normal children was also studied longitudinally on two occasions. The exercise was performed on an upright bicycle ergometer using a continuous graded exercise protocol. Parameters measured were heart rate, systolic and diastolic blood pressure at rest, and these pressures at the maximal voluntary exercise level. In addition, a subset of patients and controls had measurement of cardiac output by a modified acetylene rebreathing technique. Results indicate that coarctation patients had significant elevation of systolic and diastolic blood pressures at rest (p less than 0.001 for both) and with exercise (p less than 0.02 for both) prior to surgery. The group mean values for systolic and diastolic blood pressure did not differ from control values after surgery; however, some individuals continued to have hypertension at rest when compared to population-based norms. Heart rate, cardiac index, and stroke volume index did not differ from those of control subjects either at rest or during exercise before or after surgery. In conclusion, a group of coarctation patients studied longitudinally demonstrated marked improvement in both systolic and diastolic hypertension after surgery. The findings of normal cardiac output and stroke volume indices may have implications for the etiology of postoperative hypertension.

Aortic Coarctation↗
PubMed1989

Cardiac performance in children with pectus excavatum.

Fourteen children with pectus excavatum and 14 normal control patients underwent graded exercise testing using a cycle ergometer and the James protocol. All the subjects were preoperative. The children were exercised to exhaustion during the test. The pectus and control groups were broken down into subgroups consisting of subjects less than or equal to 10 years of age and subjects greater than or equal to 11 years of age (pectus and controls less than or equal to 10 years old, PI and CI, respectively; pectus and controls greater than or equal to 11 years old, PII and CII, respectively). Maximal workload, oxygen consumption, cardiac output, and stroke volume were not significantly different when comparing the total groups or when each of the respective subgroups were compared. However, maximal diastolic BP was significantly elevated when the entire pectus and control groups were compared. When the subgroups were compared, maximal diastolic BP was elevated only in the older pectus patients (PII) and remained so until five minutes after exercise. Additionally, left ventricular systolic time intervals were measured immediately after exercise in all the children. The ratio of preejection period to left ventricular ejection time (P/L) was significantly shortened in the total pectus group. When the subgroups were compared, the P/L ratio was significantly decreased only in the older patients. Also, the preejection period (PEP) was significantly shortened in the older pectus patients. It appears that children with pectus excavatum have a normal exercise tolerance and oxygen transport. However, older pectus children develop an increased diastolic BP and a shortened P/L and PEP in response to exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Comparison of the cardiac output and stroke volume response to upright exercise in children with valvular and subvalvular aortic stenosis.

Cardiac output and stroke volume were evaluated in 17 children (mean age 11.5 +/- 3 years) with discrete, membranous subvalvular (Group I, n = 7) and valvular (Group II, n = 10) aortic stenosis during submaximal and maximal (greater than 75% predicted maximal oxygen consumption) upright cycle ergometry. Patients with valvular aortic stenosis were further subdivided on the basis of their aortic valve gradient at rest determined by cardiac catheterization (Group IIA, gradient less than 40 mm Hg; Group IIB, gradient greater than or equal to 40 mm Hg). These patients were matched with 17 control subjects on the basis of age, sex, height and intensity of exercise during maximal exertion. Cardiac and stroke indexes were determined by the acetylene rebreathing method at each exercise level. Stroke volume index in Group I was significantly greater at rest when compared with that in control subjects (69 +/- 13 versus 53 +/- 11 ml/m2, alpha = 0.01, p less than 0.05) and that in patients in Group II (69 +/- 13 versus 47 +/- 12 ml/m2, alpha = 0.01, p less than 0.05). Patients with subvalvular aortic stenosis were unable to increase their stroke volume index from rest to submaximal exercise and also decreased their stroke volume index at maximal exercise levels. In contrast, patients with mild valvular aortic stenosis (Group IIA) displayed a normal exercise response. Patients with severe valvular aortic stenosis (Group IIB) had a blunted stroke volume response at rest and at each level of exercise, as well as signs of myocardial ischemia (ST segment depression) during maximal exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

A histologic study of laser-induced transmyocardial channels.

Carbon dioxide lasers are reported to provide ischemic myocardium direct access to blood within the ventricular cavity by inducing transmyocardial channels which maintain patency in long-term experiments. We have histologically examined the natural history of channels produced with this technique and compared them with transmyocardial channels created by needle puncture. Immediately after application of the laser, four concentric zones vaporization, carbonization, fixation, and transition could be distinguished along the transmyocardial path. Needle puncture channels were fully occluded within 48 hr, whereas laser-induced channels maintained partial patency for a 2-week period, after which they also became occluded. It appears likely that the instantaneous vaporization produced by the laser may delay the release of factors which mediate the healing process, but occlusion of channels was universal in this study. It remains to be determined whether or not variables such as wattage, beam diameter, or tissue temperature influence long-term channel patency.

Animals↗
PubMed1987

Correlates of resting and maximal exercise systolic blood pressure after repair of coarctation of the aorta: a multivariable analysis.

Repair of coarctation of the aorta may not prevent the subsequent development of elevated systemic blood pressure at rest or with exercise. The correlates of late postoperative resting systolic blood pressure and maximal exercise systolic blood pressure levels were investigated in a retrospective study of 42 patients who had graded exercise tests after correction of coarctation of the aorta. The independent variables studied included height, weight, body surface area, age at surgery, age at exercise testing, the time interval between surgery and exercise testing, the highest systolic blood pressure prior to surgery, gradient across the coarctation at preoperative catheterization, and the residual postoperative gradient across the coarctation. The same combination of independent variables provided the best regression model for explanation of the variance of both postoperative resting and maximal exercise systolic blood pressure. The models included height, highest preoperative systolic blood pressure, and residual gradient. None of the other variables added significant explanatory ability to either model. These findings suggest that the preoperative level of systolic blood pressure may be the best determinant of timing the corrective surgery. It may be possible to defer the operation, as long as blood pressure remains normal, until an age when repair is less likely to result in recurrent coarctation.

Adolescent↗
PubMed1985

Concomitant psychological and cardiac improvement during successful treatment of anorexia nervosa.

A patient with anorexia nervosa in whom concurrent nutritional, psychological, and cardiovascular assessments were obtained sequentially during successful treatment is presented. At the time of diagnosis, severe multisystem dysfunction was present including depression, low self-esteem, hypotension, bradycardia, exercise intolerance, and abnormalities of systolic and diastolic cardiac function. Treatment resulted in weight gain and increased skinfold thickness and arm circumference. There were concomitant improvements in the psychometric indices of depression and self-esteem as well as decreased anorectic tendencies. During her recovery, working capacity increased and diastolic function improved. However, echocardiographic evidence of impaired systolic function persisted. Despite the apparent treatment success in this patient, this report suggests a potential need for further studies to determine the extent, if any, of long-term cardiac sequelae.

Adolescent↗
PubMed1984

Maximal exercise in children with aortic regurgitation: an adjunct to noninvasive assessment of disease severity.

Twenty-five asymptomatic children with chronic aortic regurgitation were evaluated by graded bicycle exercise testing and standard resting M-mode echocardiogram. These results were compared to those of 35 normal controls matched for age and body surface area. Twenty-one patients underwent cardiac catheterization to rule out associated lesions. Patients fell into two groups based upon the left ventricular end-diastolic volume per body surface area (LVEDVI): group I (n = 10) had LVEDVI less than or equal to 2 SD from the mean of normal; group II (n = 15) had LVEDVI greater than or equal to 4 SD from the mean of normal. All had normal shortening fraction and velocity of circumferential fiber shortening. At maximal exercise, patients in group I were found to have no significant differences from normals in maximal workload, total work, percent maximal oxygen consumption, heart rate, blood pressure, or ST segment depression. However, patients in group II had blunted mean maximal exercise heart rate (p less than 0.001), systolic hypertension (p less than 0.05), and increased frequency and maximal amplitude of ST depression (p less than 0.01, p less than 0.001, respectively) compared to normal controls. Within group II the mean maximal amplitude of ST depression was significantly related to increasing LVEDVI (r = 0.53, p less than 0.05). The mean maximal exercise heart rate, systolic blood pressure, and maximal amplitude of ST segment depression were significantly related to LVEDVI for patient groups and normal controls together (r = -0.384, p less than 0.01; r = 0.28, p less than 0.05; r = 0.70, p less than 0.001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Aortic valve replacement in childhood: evaluation of left ventricular function by electrocardiography, echocardiography and graded exercise testing.

Preoperative and postoperative left ventricular (LV) performance was evaluated noninvasively in 15 children who survived aortic valve replacement (AVR). The noninvasive evaluation included electrocardiography, M-mode echocardiography, and graded exercise testing. Clinically, there was dramatic improvement postoperatively: All but 2 patients were asymptomatic. No conduction defects or arrhythmias were detected preoperatively; however, in the late postoperative period there was a variety of intraventricular conduction abnormalities, myocardial infarctions, and ventricular or supraventricular arrhythmias. On M-mode echocardiography, children with aortic stenosis continued to have increased LV mass postoperatively. Shortening fraction and left-sided systolic time intervals returned to normal. The children with aortic regurgitation also had persistently abnormal LV mass on echocardiography postoperatively. Exercise data indicated no improvement in working capacity after AVR. Also, 9 children (63%) continued to have ST-segment depression with maximal exercise. These data indicate that AVR does not result in a return to normal of myocardial performance in children with severe aortic valve disease.

Adolescent↗
PubMed1982

Exercise electrocardiogram, blood pressure, and working capacity in young patients with valvular or discrete subvalvular aortic stenosis.

Electrocardiographic changes, blood pressure, and working capacity (total work) were recorded during an upright cycle exercise test in 65 children and young adults (mean age 12 years) with valvular or discrete subvalvular aortic stenosis. All patients had cardiac catheterization, but none had surgical treatment. Controls consisted of 164 normal subjects (mean age 15 years). In the patients, the intervals between the exercise test and cardiac catheterization were 1 month or less in 66%, 2 to 12 months in 28%, and 12 to 24 months in 6%. The patients were classified by resting left ventricular to aortic peak systolic pressure gradient into Groups I (gradient less than 30 mm Hg), II (30 to 49 mm Hg), III (50 to 69 mm Hg), and IV (70 mm Hg or greater). The mean frequency and magnitude of exercise-induced S-T depression were greater in the patients than in the control subjects (p less than 0.005) and increased with increasing obstruction in the patients. Mean total work and peak exercise systolic pressure were significantly decreased in the patients with a left ventricular to aortic systolic gradient of 30 mm Hg or greater as compared with the control subjects (p less than 0.03). An exercise profile consisting of S-T depression of 2 mm or more, and markedly decreased total work and systolic blood pressure were characteristic of the 19 patients (Group IV) with a resting left ventricular to aortic systolic gradient of 70 mm Hg or greater. At least 2 or more components of this exercise profile occurred in 11 (24%) of the 46 patients with a resting left ventricular to aortic systolic gradient less than 70 mm Hg. This study demonstrates that exercise testing reveals serious abnormalities in patients otherwise classified as having trivial or moderate obstruction, and that a properly performed exercise study can be done at minimal risk to the patient.

Adolescent↗