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Biomedical subjects

J Myers

Publications and source records attributed to J Myers.

At least 199 records · Page 11Linked to original sources
PubMed1987

Perceived exertion and gas exchange after calcium and beta-blockade in atrial fibrillation.

Nine male patients (mean age 65 yr) with chronic atrial fibrillation underwent maximal exercise testing during placebo, beta-adrenergic (celiprolol, 600 mg), or calcium (diltiazem, 30 or 60 mg four times daily) channel blockade. The results were analyzed to determine which factors most closely related to ratings of perceived exertion (RPE) during exercise. Heart rate (HR), blood pressure (BP), oxygen uptake (VO2), minute ventilation (VE), and carbon dioxide production (VCO2) were evaluated at rest, 3.0 mph/0% grade, the gas exchange anaerobic threshold (ATge), 80% of placebo maximal O2 uptake, and maximal exercise. Both beta-adrenergic and calcium channel blockade significantly reduced heart rate and systolic blood pressure relative to placebo; these effects were more profound during beta-adrenergic blockade and as exercise progressed. Correlation coefficients and estimates of slope were derived for changes in RPE during exercise vs. changes in HR, VO2, VE, and VCO2 during the three treatments (r = 0.76 to 0.92, P less than 0.001). Although RPE was significantly correlated with HR during placebo and diltiazem therapy (r = 0.45, P less than 0.01), this was not the case during beta-adrenergic blockade (r = 0.31, NS). Slope of the regression lines between RPE and VO2, VE, and VCO2 did not differ between the three treatments. Slope of the regression lines between RPE and HR differed only during calcium channel blockade. Because the presence of atrial fibrillation and beta-adrenergic blockade altered the associations between RPE, VO2, and HR, these results suggest that VE is more closely related to RPE than the other parameters.

Adrenergic beta-Antagonists↗
PubMed1987

Adinazolam--a new antidepressant: findings of a placebo-controlled, double-blind study in outpatients with major depression.

Adinazolam mesylate, a new triazolobenzodiazepine with antidepressant properties, was significantly superior to placebo based on the following efficacy measures: number of subjects who completed the study; number of subjects whose total score on the 21-item Hamilton Rating Scale for Depression (HAM-D) decreased by 50% or more; and number of subjects who reported that the drug helped them. Mean scores on three HAM-D clusters (anxiety/somatization, sleep disturbance, and an endogenomorphic cluster) also showed significant differences in favor of adinazolam. Side effects were generally mild and transient; however, a seizure of moderate intensity occurred during rapid tapering of adinazolam from 90 to 40 mg/day. There were no significant anticholinergic effects, and no mania or hypomania was reported in any subject. No consistently significant differences were observed between subjects whose primary diagnosis was major depression and those with a diagnosis of bipolar II depression.

Adult↗
PubMed1986

Computer analysis of exercise-induced changes in QRS duration in patients with angina pectoris and in normal subjects.

Exercise-induced changes in QRS duration were assessed in 25 normal subjects and in 17 patients with stable ischemic heart disease. None had bundle branch block or were taking medications, and all patients had angina pectoris induced during the test. QRS duration and ST60 amplitude were measured by computer during rest while standing, at a heart rate of 100 to 110 bpm during exercise, at peak heart rate for the angina patients (mean of 127 bpm), and at the corresponding matched heart rate and peak heart rate for the normals (mean of 174 bpm). As heart rate increased, the patients showed significant ST60 depression. In normal subjects, the QRS duration tended to increase initially but at the matched heart rate level and at peak heart rate it decreased significantly compared to rest (p less than 0.01). The QRS duration in the angina patients increased significantly at the heart rate level of 100 to 110 bpm (p less than 0.05). Of the eight patients who reached a peak heart rate above 127 bpm, six (75%) during that period further increased QRS duration compared to three (12%) of the 25 normal subjects (p less than 0.001). We conclude that a consistent increase in QRS duration during exercise, although subtle, may be a marker of ischemia and consequently a potential diagnostic tool.

Adult↗
PubMed1986

Treatment of stages I and II Hodgkin's disease with three different therapeutic modalities.

Since 1969, 184 previously untreated and evaluable adult patients with Hodgkin's disease, staged as I (43) or II (141), have been treated. Eighty patients were part of the National Hodgkin's Disease Study, randomly assigned to receive radiotherapy to either an involved (39) or extended field (41). In a subsequent single-arm study, 104 patients were treated with involved-field radiotherapy preceded and followed by three cycles of MOPP chemotherapy. Median durations of follow-up have been 172, 172, and 92 months, for the involved-field radiotherapy, extended-field radiotherapy, and MOPP plus involved-field radiotherapy treatment groups, respectively. Although significant differences among the three treatment groups were observed with respect to disease-free survival (p less than 0.001), only the group of patients treated with involved-field radiotherapy had a statistically significant decline in overall survival as compared with the two other treatment groups (p less than 0.001). Moreover, patients who underwent clinical staging and were treated with MOPP plus involved-field radiotherapy had significantly prolonged disease-free survival compared with those who underwent surgical staging and were treated with extended-field radiotherapy (p less than 0.001). One of the patients who received MOPP plus involved-field radiotherapy had subsequent development of acute monocytic leukemia, and another had refractory anemia with excess blasts. One instance of diffuse poorly differentiated lymphocytic lymphoma was also observed. Acute monocytic leukemia developed in another patient treated with involved-field radiotherapy. The rates of amenorrhea in the group treated with MOPP plus involved-field radio-therapy were 9.6 percent and 78.5 percent for female patients younger and older than 30 years of age, respectively. Despite the universal azoospermia ensuing after MOPP plus involved-field radiotherapy, in three patients whose sperm counts were checked sequentially for 26 to 53 months after treatment, evidence of spermatogenesis was observed. Three patients with remission of Hodgkin's disease after involved-field (two) and extended-field (one) radiotherapy died from cardiovascular disease that could only be attributed to the prior radiotherapy. Although further follow-up evaluation will be required to determine the impact of the three different treatment modalities on survival and long-term toxicity, MOPP plus involved-field radiotherapy appears to be superior to involved-field or extended-field radiotherapy alone in achieving prolonged disease-free survival without significant leukemogenic potential.

Adult↗
PubMed1986

Modelling the incidence of childhood diarrhea.

Diarrheal disease is a primary cause of childhood mortality and morbidity in developing countries. Significant reduction depends on the identification of high-risk households which can be targetted for proven-effective interventions, such as oral rehydration therapy. This paper describes the development of a household risk assessment model in the context of an on-going diarrheal disease control in Grenada. Contingency and logit analyses of household survey data are used to identify easily observed markers of high-risk households. A three-variable logit model gives accurate predictions of self-reported diarrhea, showing that the approach can be used to develop an effective and efficient risk assessment tool.

Child↗
PubMed1986

A comparison of patient acuity and nursing resource use.

An analysis of patient records in four different DRG categories estimated direct nursing care requirements. The evaluation of these results showed a great range in direct hours of nursing care, as well as resultant cost of nursing care within and among the DRG categories. Nursing resource use is widely fluctuating based on acuity levels, length of stay, and DRG category. Thus, it was concluded the variables inherent in a model to predict cost rely on determinants of the functional needs of the individual patient.

Aged↗
PubMed1986

Copper, zinc, and iron in normal and leukemic lymphocytes from children.

Copper, zinc, and iron were quantitated in the serum and lymphoid cells of the peripheral blood of healthy children and children with acute lymphocytic leukemia. Copper and iron concentrations in serum and cells were significantly higher and zinc concentration in the cells significantly lower in leukemic patients than in healthy donors, whereas the increase of zinc in the serum was not significant. The concentration of all minerals was higher in T-cell enriched preparations. There was a significant correlation between copper and iron and between copper and zinc, but not between iron and zinc in normal and leukemic lymphocytes. No correlation was demonstrated among the three minerals in the serum. There were no significant differences associated with ethnicity, age, sex, type of leukemia, or number of leukemic cells. However, a group of five children with non-B-, non-T-cell acute lymphocytic leukemia, nonreactive skin tests, and low serum immunoglobulins had high concentrations of copper and iron and low concentration of zinc in their leukemic cells. Since copper, zinc, and iron are associated with lymphocyte maturation and regulation of immune function, these new data will provide a tool for the study of the relationship between changes in concentrations of these metals and the modification of the immune response often present in hematologic cancers.

Child↗
PubMed1986

Umbilical blood pressures and utero-placental blood flow in spontaneously hypertensive rats.

Some substrains of spontaneously hypertensive rats (SHR) are hypertensive at birth, suggesting the possibility of pre-natal hypertension. Fetal haemodynamics are sensitive to utero-placental blood flow changes. Thus, we used micropuncture to measure umbilical vein blood pressure (BP) in SHR and Wistar-Kyoto rats (WKY) at 18 and 20 days post-conception. We determined utero-placental blood flow (UPBF) at 17 and 20 days post-conception by the microsphere method. Results showed that SHR fetuses were hypertensive only at 20 days. Fetal heart:body weight ratio was higher in SHR, decreased with age and was not associated with BP or heart rate. Utero-placental weight was not affected by either age or strain. However, utero-placental blood flow was low in SHR at 20 days. Thus, in SHR pre-natal hypertension occurs between 18 and 20 days post-conception; pre-natal hypertension is associated with low utero-placental blood flow.

Animals↗
PubMed1986

Australian National Health and Medical Research Council dietary salt study in mild hypertension.

Two-hundred-and-twelve untreated subjects (mean age 52.3 +/- 0.8 years; 181 males and 31 females) with a diastolic blood pressure between 90 and 100 mmHg were recruited to the study. Subjects were seen fortnightly and, after 4 pre-diet visits, were randomized into a normal diet group (A, 55 subjects), a high-potassium diet group (B, 52 subjects receiving greater than 100 mmol K+/day) a reduced-sodium diet group (C, 52 subjects receiving 50-75 mmol Na+/day) or a high-potassium and low-sodium diet group (D, 53 subjects receiving same Na+ and K+ as groups B and C). Two-hundred subjects completed the diet phase of 12 weeks. Urine sodium fell to 86 +/- 7 mmol/day in group C and 73 +/- 6 mmol/day in group D, while daily potassium excretion rose to 96 +/- 5 mmol in group B and 87 +/- 4 mmol in group C. Systolic and diastolic blood pressure fell by 3.8 +/- 1.0 and 1.6 +/- 0.6 mmHg respectively in the normal diet group. The falls in systolic and diastolic blood pressures (mmHg) in the diet phase were 7.7 +/- 1.1 and 4.7 +/- 0.7 (B), 8.9 +/- 1.0 and 5.8 +/- 0.6 (C) and 7.9 +/- 0.9 and 4.2 +/- 0.7 (D). These falls were all greater than those in the control group on an intention-to-treat analysis (P less than 0.005) but did not differ from each other. Factorial analysis confirmed that the falls in pressure attributable to the low-sodium diet and high-potassium diet were not additive.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1985

Can patients with coronary artery disease receiving beta blockers obtain a training effect?

Fifty-nine male volunteers with stable coronary artery disease underwent 1 year of supervised exercise and were compared with 69 similar control patients. Both groups underwent exercise tests initially and at 1 year to determine maximal oxygen uptake. Initial and 1-year tests were performed with patients off all cardiac medications including beta blockers. Although patients had been randomized to exercise intervention, administration of beta blockers was at the prerogative of their physicians. Thirty-seven percent of the trained group and 39% of the control group were taking beta blockers during the year of study. Regardless of whether or not beta blockers were administered, patients in the exercise intervention group had a significant increase in aerobic capacity and improvement in the other hemodynamic markers of training compared with control subjects. Of the trained patients, those on beta blockers were able to comply with the exercise regimen as well as those not taking beta blockers.

Adrenergic beta-Antagonists↗
PubMed1985

Spatial R wave amplitude changes during exercise: relation with left ventricular ischemia and function.

Thirty patients who exhibited increased and 65 patients decreased spatial R wave amplitude during exercise testing were compared for left ventricular function and ischemic variables. Spatial R wave amplitude was derived from the three-dimensional Frank X, Y, Z leads using computerized methods. All patients had stable coronary artery disease and they were classified into two groups: one that attained a higher (n = 48) and one a lower (n = 47) median value of maximal heart rate during exercise (161 beats/min). Within these two groups, patients with increasing or decreasing spatial R wave amplitude during exercise were analyzed for differences in oxygen consumption, exercise-induced changes in spatial R wave amplitude, ST segment depression laterally (ST60, lead X), ST displacement spatially, left ventricular ejection fraction at rest, change in left ventricular ejection fraction with exercise and thallium-201 ischemia during exercise. Significant differences were demonstrated only in exercise-induced spatial R wave amplitude changes (p less than 0.0001). There was no significant correlation between exercise-induced change in heart rate and change in spatial R wave amplitude in either the group with increasing or the group with decreasing spatial R wave amplitude. It is concluded that changes in spatial R wave amplitude during exercise are not related to ischemic electrocardiographic or thallium-201 imaging changes or to left ventricular ejection fraction determined at rest or during exercise.

Coronary Disease↗
PubMed1985

A respiratory epidemiologic survey of grain mill workers in Cape Town, South Africa.

Exposure to grain dust may induce acute and chronic respiratory, nasal, and ocular symptoms. The prevalence of respiratory symptoms, atopic status, and lung function changes, as measured by pulmonary function tests (PFT) over the week in 582 grain mill workers and 153 control subjects not exposed to grain dust were studied in Cape Town. Atopic status, smoking habits, and baseline PFT did not differ significantly between grain workers and control subjects. Grain workers showed significant deterioration in lung function values over the week, with forced expiratory volume in one second declining on average by 4.8% compared with an increase of 3.3% in control subjects (p less than 0.001). Forced expiratory flow during the middle half of the forced vital capacity declined by 14.8% in grain workers and by 0.8% in control subjects (p less than 0.0001). Grain workers had significantly higher prevalences than did control subjects of regular cough (46 versus 30%), expectoration (35 versus 17%), wheeze (25 versus 11%), and watery eyes (25 versus 10%) (p less than 0.01 for all). These symptoms were not related to the duration of employment. A dose-response relationship, independent of smoking habits, was demonstrated between reported dust exposure and symptoms as well as between dust exposure and PFT. These results have important implications for the grain mill industry in South Africa where there is insufficient legislation and worker compensation.

Adult↗
PubMed1984

Predicting oxygen uptake from treadmill testing in normal subjects and coronary artery disease patients.

In order to evaluate the clinical practice of estimating oxygen uptake from treadmill time, patients with coronary heart disease and normal subjects had their oxygen uptake measured during treadmill testing. Continuous expired gas analysis was performed in order to see if the gas exchange anaerobic threshold could explain the difference between measured and estimated oxygen uptake. Below the gas exchange anaerobic threshold, normal subjects and patients had similar oxygen uptakes for a given workload. However, at workloads above this threshold, patients had approximately 1 MET lower oxygen uptake than normal subjects. Regression equations relating treadmill time to oxygen uptake are specific to groups of patients or individuals due to differences in anaerobic threshold. In addition, the use of standard workloads to predict aerobic capacity depends on the rate at which oxygen uptake obtains a steady state value. These findings must be considered in clinical practice when attempting to estimate aerobic capacity from treadmill testing.

Coronary Disease↗
PubMed1984

Treatment of advanced Hodgkin's disease with chemotherapy and irradiation. Controlled trial of two versus three alternating, potentially non-cross-resistant drug combinations.

From January 1979 to June 1983, 71 evaluable, previously untreated patients with advanced Hodgkin's disease completed a randomized trial of two or three potentially non-cross-resistant drug combinations and low-dose radiotherapy to initially involved nodal regions (2,000 to 3,000 rads). All patients received nine cycles of alternating chemotherapy regimens and radiotherapy between cycles 6 and 7. Thirty-four patients received three combinations: lomustine, melphalan, vindesine (CAD), MOPP, and doxorubicin, bleomycin, vinblastine (ABV). The complete remission rate was 82 percent, partial remission rate 12 percent, and progression rate 6 percent. There were two relapses from complete remission and three deaths. Thirty-seven patients received MOPP and ABV plus dacarbazine (D). The complete remission rate was 78 percent, partial remission rate 16 percent, and progression rate 6 percent, with three relapses from complete remission and five deaths. Myelosuppression was more frequent with CAD/MOPP/ABV/radiotherapy, and nausea and vomiting with MOPP/ABVD/radiotherapy. The results for both are among the best reported, and CAD/MOPP/ABV/radiotherapy was more acceptable to patients.

Adolescent↗
PubMed1984

A randomized trail of the effects of 1 year of exercise training on computer-measured ST segment displacement in patients with coronary artery disease.

As part of a randomized trial of the effects of 1 year of exercise training on patients with stable coronary artery disease, 48 patients who exercised and 59 control patients had computerized exercise electrocardiography performed initially and 1 year later. The patients who had exercise training as an intervention had a 9% increase in measured maximal oxygen consumption and significant decreases in heart rate at rest and during submaximal exercise. ST segment displacement was analyzed 60 ms after the end of the QRS complex in the three-dimensional X, Y and Z leads and utilizing the spatial amplitude derived from them. Statistical analysis by t testing yielded no significant differences between the groups except for less ST segment displacement at a matched work load, but this could be explained by a lowered heart rate. Analysis of variance yielded some minor differences within clinical subgroups, particularly in the spatial analysis. Obvious changes in exercise-induced ST segment depression could not be demonstrated in this heterogeneous group of selected volunteers with coronary artery disease secondary to an exercise program.

Adult↗