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Biomedical subjects

W G Wolfe

Publications and source records attributed to W G Wolfe.

At least 91 records · Page 5Linked to original sources
PubMed1980

Angiographic evaluation of chronic pulmonary embolism.

In some patients acute pulmonary emboli may fail to resolve normally, resulting in chronic pulmonary embolism. This may lead to pulmonary hypertension, respiratory insufficiency, cor pulmonale, and death. The angiographic evaluation in nine patients with chronic pulmonary embolism who underwent embolectomy is presented. Particular emphasis on the predictive value of selective bronchial arteriography in four of these patients is considered. In chronic pulmonary embolism, pulmonary arteries distal to obstructed areas may remain patent and be supplied by hypertrophied bronchial arteries. Since back-bleeding of arterial blood from the bronchial circulation at surgery may predict the success of embolectomy, preoperative bronchial arteriography may be useful for predicting potential surgical success.

Adult↗
PubMed1980

Pulmonary tuberculosis in children.

A major change has occurred in the incidence and management of pulmonary tuberculosis in patients of all ages. This review emphasizes the effectiveness of drug therapy and the declining role of surgical management of pulmonary tuberculosis in children. Surgical intervention was necessary in only two of 140 children (1.4%) with proved tuberculosis, one for a large tuberculoma and the other for refractory involvement of the chest wall. The remaining 138 children were treated successfully with anti-tuberculous drugs. Pulmonary tuberculosis in children is primarily a medical disease and only rarely is surgical intervention indicated.

Adolescent↗
PubMed1978

Popliteal artery aneurysms. Past and present.

Popliteal artery aneurysms have had an important historic role in the development of modern vascular surgery. Early methods of surgical therapy for these aneurysms are detailed in this report for a persepctive. Clinical aspects of surgical diagnosis and treatment of 35 popliteal artery aneurysms in 26 patients are also reviewed. Such aneurysms often present with varied symptoms and should be considered a treacherous disease entity since limb loss occurs in a considerable number of patients. Coexisting disease frequently complicates both the intraoperative and postoperative course of these patients. In this series of popliteal aneurysms, excision and venous autograft interposition offered the most successful operative therapy.

Aneurysm↗
PubMed1978

Hemodynamic effects of prolonged hyperoxia.

Experimental studies have consistently demonstrated the development of perivascular edema in the dog lung following prolonged exposure to 95% oxygen. This pathological change has been thought to result from capillary injury, but a direct effect secondary to left ventricular dysfunction has not yet been excluded. To evaluate the latter possibility, ten trained, awake dogs were prepared with monitoring of right and left atrial, systemic and pulmonary artery pressures, cardiac output, and mixed venous and arterial blood gases. Animals were exposed to an F1O2 greater than 0.95 for 48-70 hours. Radioactive 8-10 mu microspheres (141Ce, 51Cr, 85Sr, 46Sc) were injected into the left atrium at zero, six, 24, and 48 hours. PaO2 was 480 +/- 10 mm Hg during exposure, and the pulmonary shunt fraction increased from 11.3% to 16.9% (p less than 0.0001) during 70 hours. Left atrial pressure fell from 9 +/- 2 mm Hg to 3 +/- 3 mm Hg (p less than 0.0001), but cardiac output was constant at 2.7 +/- 0.1 l/min. Pulmonary arteriolar resistance increased from 183 +/- 20 dynes-sec-CM-5 to 791 +/- 30 at 70 hours (p less than 0.0001). Histologic sections of the lungs demonstrated the characteristic perivascular edema. Of particular interest was the fact that myocardial perfusion was significantly increased to all three layers of the ventricular wall at 24 and 48 hours. These data indicate that perivascular edema developing after exposure to high concentrations of oxygen is secondary to pulmonary capillary endothelial damage with no evidence that myocardial dysfunction occurs during this period.

Animals↗
PubMed1978

Reversible pulmonary oxygen toxicity in the primate.

In order to investigate the effects of high concentrations of oxygen on the lung, experiments were performed on 18 baboons exposed to a humidified environment of 95% oxygen for five days. Open lung biopsies for biochemical assay, histologic and electron microscopic analysis and measurement of tissue respiration were performed before and after oxygen exposure. Pulmonary function was evaluated by measurement of arterial blood gases, compliance, closing capacity (CC), functional residual capacity (FRC), total lung capacity (TLC), residual volume (RV) and vital capacity (VC) before and after exposure and then at seven and 14 days in the animals which recovered. Six baboons removed from the oxygen environment after 96--110 hours and exposed to room air died within three to 20 hours of profound hypoxemia (PaO2 40 +/- 6). The remaining 12 baboons were successfully weaned to room air over a three day period with a return of ABGs to control values (PaO2 89+/- 2). Electron microscopic analysis of alveolar membranes exposed to 120 hours of hyperoxia demonstrated endothelial cell swelling, interstitial alveolar membrane edema, and an increased predominance of Type II pneumocytes. Lung volume measurements showed significant decreases in TLC (25%), VC (34%), CC/TLC (28%) and dynamic compliance (47%). Biochemical studies indicated a shift toward anaerobic metabolism with a decrese in tissue oxygen consumption, reduced cytochrome oxidase activity, and increased lung lactic acid production. These changes were all found to be reversible in the 12 baboons slowly weaned back to room air.

Animals↗
PubMed1978

Social cues, cognitive style, error magnitude, and male performance on the Felt Figure Replacement Technique.

A series of studies was undertaken to determine possible factors contributing to low predictive utility for Felt Figure Replacement Technique (FFRT) scores from normal, adult males. It was first postulated that normal adult males, compared to normal adult females, are less sensitive to social cues present in the FFRT task. Twenty-six undergraduate males and the same number of undergraduate females were asked to replace both a) department store manikins, thought to be less abstract, and then b) felt figures. While task differences were obtained, these were not dependent on gender, nor did any overall gender differences occur for three types of replacement error. The second study involved 31 college males and 33 college females replacing both felt figures and a male and female confederate. It was assumed that differential attention to social cues would be more visible in this comparison. The general results were identical to the first study.

Cognition↗
PubMed1977

Heparin-coated shunts for lesions of the descending thoracic aorta. Experimental and clinical observations.

Heparin sodium-coated shunts are employed frequently to maintain trunk and lower extremity perfusion during temporary occlusion of the descending thoracic aorta. In the past five years, this shunt has been used in a series of 39 patients ranging in age from 19 to 72 years old, with 34 survivors (87%). The proximal end of the shunt was placed in the subclavian artery in 17 patients, the left ventricle in ten, and in the ascending or transverse aortic arch in 12. The distal end of the shunt was placed either in the lower thoracic aorta or in the femoral artery. For further evaluation of effectiveness, paired observations were made in dogs to determine the physiological consequences with the proximal end of the shunt inserted at two different sites. Although neither shunt decompressed the left ventricle fully, the subclavian-femoral shunt was significantly more effective than was the left ventricle-femoral artery bypass. If a choice exists for sites of insertion of the shunt, it appears that it should be placed distal to the aortic valve, since this position provides the least increase in systolic blood pressure and is associated with a lower demand for myocardial blood flow.

Adult↗
PubMed1977

Surgical management of chronic pulmonary embolism.

The clinical course of most patients with pulmonary embolism is one of gradual resolution with re-establishment of flow in the pulmonary arteries. In a small but definite group of patients, the emboli do not resolve and a state of chronic pulmonary embolism ensues. The primary thrombotic process in the systemic venous system may persist, and in some instances may be unrecognized. Such patients experience recurrent showers of emboli which may ultimately occlude a large part of the pulmonary arterial circulation with development of severe respiratory insufficiency. Six patients with this syndrome are described, and in each there was a history of dyspnea, cyanoiss, and exercise intolerance associated with a low arterial PO2, right ventricular hypertrophy, and pulmonary hypertension. Pulmonary scans and arteriograms demonstrated that more than half of the major pulmonary arteries were occluded and, in addition, smaller vessels were also obstructed. Pulmonary embolectomy was performed in each patient. Five of the 6 obtained a highly gratifying response, including relief of the dyspnea and cyanosis, an increase in arterial PO2, and a decrease in pulmonary arterial pressure. In each of the five in whom improvement occurred, the back-bleeding from the pulmonary artery at the time of embolectomy was quite good. In the sixth patient, the back-bleeding was very poor, and despite embolectomy, the vessel thrombosed postoperatively with no improvement in the patient's clinical course. Follow-up studies in these patients range up to 8 years with demonstration of continued patency of the pulmonary arteries as well as continued improvement in clinical symptoms and in the arterial PO2.

Adult↗
PubMed1977

The Felt Figure Replacement Technique as a personality assessment device: validity reconsidered.

Conclusions from an earlier study testing the validity of the Felt Figure Replacement Technique (FFRT) were questioned and three new measures of FFRT performance were developed. The reliability of these three measures, and the conventional measure of distance error, was checked using a sample of 54 female and 49 male undergraduates at Oregon State University. These subjects also completed an established personality inventory. Three of the four FFRT measures tested proved to be reliable, and it was found that models combining the three reliable FFRT measures could yield successful predictions on the personality dimensions for females but not for males; although males and females perform similarly on the FFRT. Both groups made the same kinds of errors relative to the standard placement. Also, males and females differ on only one of the three reliable FFRT measures. It was concluded that the FFRT may yet prove a valuable assessment approach, and the implications of these conclusions for personality assessment were discussed.

Journal Article↗
PubMed1977

Regional pulmonary function during experimental unilateral pneumothorax in the awake state.

This study examines changes in regional pulmonary function during unilateral pneumothorax, immediately after, and 2 hours following re-expansion in awake dogs. Respiratory rate, tidal volume, physiologic dead space, arterial blood gases, and pulmonary shunt fraction were determined at each stage. Cardiac output (thermodilution), vascular pressures, and regional ventilation and perfusion (133Xe scans) were also measured. Chest roentgenogram confirmed the presence of UP. Respiratory rate increased 124 percent (p less than 0.01) during UP while alveolar ventilation remained unchanged. Pulmonary shunt fraction rose 93 percent (p less than 0.01) during UP, causing PaO2 to fall from 86 to 51 mm. Hg (p less than 0.01). PaCO2, pH, and cardiac output were not altered by UP. UP caused a relative underventilation of the collapsed lung (V/Q = 0.73 (p less than 0.01)) and an overventilation of the contralateral lung (V/Q = 1.74) (p less than 0.01). Immediately after re-expansion of the collapsed lung, all the above changes reverted to the control values. All variables remained unchanged 2 hours following complete re-expansion.

Animals↗