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Biomedical subjects

F A Gaffney

Publications and source records attributed to F A Gaffney.

66 records · Page 4Linked to original sources
PubMed1981

Adaptation to peripheral muscle training.

Ten healthy subjects underwent a 6-week dynamic exercise program designed to put a high relative load on individual muscle groups while maintaining low central circulatory stress levels. This was done to test the hypothesis that such "peripheral" training could produce skeletal muscle adaptation at low levels of myocardial work. Such a program may be useful in rehabilitating patients whose myocardial disease prevents adequate levels of participation in the traditional types of large muscle training. Strength testing, muscle biopsies and both submaximal and maximal bicycle ergometry were done to assess the effects of "peripheral" training. Heart rate during the training sessions decreased progressively over the 6 weeks (p less than 0.001). Quadriceps strength increased (p less than 0.02) with training as did both quadriceps (p less than 0.03) and gastrocnemius (p less than 0.008) fiber areas. Fiber composition was unchanged. Succinic dehydrogenase concentrations were unchanged while phosphorylase activity decreased in both muscle groups (p less than 0.03). Submaximum and maximum bicycle ergometry results were unchanged with training. The data show that dynamic training of small groups of muscles sequentially can produce significant skeletal muscle adaptation with little central circulatory stress. The effects of "peripheral" training in cardiac patients remain to be determined.

Adaptation, Physiological↗
PubMed1981

Hemodynamic changes during whole body surface cooling and lower body negative pressure.

Six young healthy male subjects were studied to evaluate the use of whole body surface cooling (WBSC) as an antiorthostatic intervention. Previous studies in our laboratory have demonstrated the perfusion of an Apollo cooling garment with 16 degrees C water produced a significant increase in stroke volume and decrease in heart rate at rest and during lower body negative pressure (LBNP). However, optimal perfusion temperatures have not been determined. The present study examined the effects of WBSC using perfusion of water at a temperature of 10 degrees C. This perfusion temperature produced a greater decrease in mean skin temperature (Tsk) than water at 16 degrees C, -4 degrees C drop compared to -2 degrees C respectively. The hemodynamic effects were also more prominent with 10 degrees C water as shown by the increase in stroke volume of 11% at rest and of 35% during LBNP at -50 torr compared to control measurements at ambient temperature. Heart rates were lowered significantly (8 beats/min) and systolic arterial blood pressure was higher (8 torr). Cooling with 10 degrees C water produced a slight increase in muscle tone, reflected by a small but significant increase (+84 ml/min) in oxygen uptake. These data suggest that WBSC is an effective nonpharmacologic means of controlling preload and deserves further investigation as an antiorthostatic intervention.

Adult↗
PubMed1980

Severe pulmonary hypertension associated with macronodular (postnecrotic) cirrhosis and autoimmune phenomena.

The clinical and pathologic findings are reported in seven consecutive patients with progressive and fatal pulmonary hypertension which was not explained by predisposing cardiac or pulmonary diseases. Pulmonary arterial lesions consisted of atherosclerosis of the elastic pulmonary arteries, and medial hypertrophy and concentric laminar fibrosis of the muscular pulmonary arteries in seven patients, plexiform lesions in six patients and necrotizing vasculitis in one patient. Pulmonary emboli were not identified. Five patients had manifestations of autoimmune disease, including laboratory abnormalities (positive antinuclear antibody, positive latex agglutination for rheumatoid factor, hypergammaglobulinemia or antimitochondrial antibody) in four, necrotizing vasculitis in one, Raynaud's phenomenon in two and clinical evidence of multisystem collagen vascular disease in two. Five patients had liver disease which developed prior to or concomitant with the onset of pulmonary hypertension. At autopsy, one patient had prominent periportal fibrosis and four had macronodular (postnecrotic) cirrhosis (active in three and inactive in one). Four of these five patients with liver disease and pulmonary hypertension had evidence of autoimmune phenomena. The findings in the seven patients suggest an association between autoimmune disease, plexogenic pulmonary hypertension and liver disease of the chronic active hepatitis-postnecrotic cirrhosis type.

Adolescent↗
PubMed1980

Interactions between surface cooling and LBNP-induced central hypovolemia.

The interaction between whole body surface cooling (WBSC) and progressive lower body negative pressure (LBNP) to -50 torr was evaluated in nine healthy male volunteers, mean age 29 +/- 1.7 years. WBSC, accomplished by circulating 16 degrees C water through an Apollo cooling garment, produced a significant drop in mean skin temperature of 1.96 degrees C (p less than 0.001). Cardiac output (Q) was measured by the C2H2 rebreathing technique. Changes in leg volume (LgV) were monitored by a Whitney strain gauge. WBSC at rest produced a significant decrease in leg volume of 0.27 I (p less than 0.01). Heart rate decreased (-7 bpm, p less than 0.01) and systolic arterial blood pressure was increased (+6 torr, p less than 0.02). The hemodynamic effects of cooling were maintained throughout progressive levels of LBNP with consistently lower leg volumes and heart rates and higher stroke volumes and systolic pressure (p less than 0.01 for all measurements). The data suggest that WBSC produces a central displacement of cutaneous venous volume resulting in an increase in stroke volume.

Adult↗
PubMed1979

Autonomic dysfunction in women with mitral valve prolapse syndrome.

Autonomic cardiovascular regulation was evaluated in 35 women, 19 with mitral valve prolapse and 16 healthy controls. Heart rate responses to the diving reflex and to phenylephrine infusion were diminished in patients. Noninvasive measures of cardiac output, heart rate, blood pressure, forearm flow and leg volume during lower body negative pressure (LBNP) showed that patients had less lower extremity pooling of blood and had lower forearm conductance. Blood pressures during LBNP rose or remained unchanged despite decreases in cardiac output of 20--25%. These data indicate that mitral valve prolapse patients have an increased venous and arterial vasoconstrictor activity. Cardiac output at rest and echocardiographic indices of contractility were normal. Patients with a history of significant ventricular arrhythmias had higher heart rates and lower forward stroke volumes than the other patients or controls. The combined data demonstrate autonomic dysfunction in women with the mitral valve prolapse syndrome and suggest decreased parasympathetic, increased alpha- and normal beta-adrenergic tone and responsiveness.

Adult↗
PubMed1978

Thallium-201 myocardial perfusion studies in patients with the mitral valve prolapse syndrome.

To determine whether regional myocardial ischemia plays a role in patients with the mitral valve prolapse syndrome, we examined myocardial perfusion with exercise stress testing and thallium-201 myocardial scintigraphy. Twelve patients were studied, 11 women and one man aged 18 to 56 years, mean age 30 years. In all patients, mitral valve prolapse was documented by echocardiography or phonocardiography. Patients over 35 years of age underwent cardiac catheterization. Electrocardograms disclosed abnormalities during maximal exercise in eight of the 12 patients. In two patients, angina developed during exercise. Thallium-201 (201Tl) scintigrams were normal in the 11 patients with presumed or documented normal coronary arteries. One patient, in whom an apical defect was demonstrated on scintigraphy, had significant disease of the left main and left anterior descending coronary artery. Repeat testing after successful aortocoronary bypass grafting revealed improved exercise capacity and a normal 201Tl myocardial scintigram. The data indicate that patients with mitral valve prolapse alone do not have regional myocardial ischemia and that the presence of a defect on 201Tl myocardial scintigraphy following maximal stress testing would suggest the existence of concomitant coronary artery disease.

Adolescent↗
PubMedDate not supplied

Oxygen uptake and cardiovascular responses in control adults and acute myocardial infarction patients during bathing.

Physiological responses before, during, and after three types of baths were determined in 18 patients who were 5 to 17 days postinfarction and 22 control adults. In the patients, oxygen consumption (VO2) averaged 6, 7, and 7 ml/kg/min, peak heart rate 105, 108, and 112 beats per minute, and rate pressure product 115, 120, and 111 for basin, tub, and shower bathing, respectively. Oxygen consumption during bathing was less than 3 times resting levels. The patients had a significantly lower VO2 during bathing than the control subjects. The patients' peak heart rates were higher than anticipated for the level of exertion, and sometimes exceeded the target heart rates used in predischarge testing. Peak heart rate and occurrence of dysrhythmia did not differ significantly between the three types of baths. In the women patients, rate pressure product was significantly higher after tub bath than after basin bath or shower. The subjects had no cardiovascular symptoms during bathing, rated all three baths as light exertion, and disliked the basin bath. The data show that the physiologic costs of the three types of baths are similar, differences in responses to bathing seem more a function of subject variability than bath type, and many cardiac patients can take a tub bath or shower earlier in their hospitalization. However, more research is needed to predict patients likely to have an exaggerated response to bathing and to develop clear guidelines for bath method selection and progression.

Adult↗
PubMedDate not supplied

Body size, composition, and fitness in adolescents with elevated blood pressures.

Increased body size is often found in children with elevated blood pressures, but it is not clear whether this is a result of obesity or early maturity. Similarly, levels of activity and fitness have marked effects on blood pressure and body composition. To study these interrelated factors, we measured height, weight, and body composition (skinfold thickness and total body water) as well as heart rate, blood pressure, and oxygen consumption at rest and during exercise in 192 ninth grade boys and girls, 102 with persistently elevated blood pressures at or above the 95th percentile and 90 matched controls with blood pressures below the 50th percentile for the entire population of 10,641 Dallas County ninth graders tested. Differences in resting blood pressures also were present during maximal exercise and recovery periods. Boys with persistently elevated blood pressures were characterized by increased supine and recovery heart rates, normal fitness, excess size for age in the absence of obesity, and early maturation. Girls with persistently elevated blood pressures had increased heart rates, decreased fitness, and obesity.

Adolescent↗