Biomedical subjects
Publications and source records attributed to R E Greene.
This note announces some theorems that show that the flat metric of euclidean space has no nearby nonflat complete metric with the property that its curvature keeps a sign and is "uniformly small" in a sense made precise here.
A simple measurement, the average interpleural distance (AID), which is obtained from three linear measurements, closely predicts true pneumothorax size as determined by radiographic thoracic gas volume measurement (mean variation -2.4 +/- 7.23 SD). The distribution of pneumothorax volume between the affected lung and the ipsilateral thoracic cage is variable and unpredictable. It was found that the average volume of pneumothorax that is accommodated by thoracic cage expansion (8%) is much less than previously reported. This appears to be the result of variable degrees of splinting and chest wall pain associated with pneumothorax.
To determine whether a correlation exists between pulmonary arterial (PA) pressure (Pa) and the distribution of pulmonary blood flow, this distribution was measured in four upright dogs in the control state and during intravenous infusions of epinephrine or prostaglandin F2 alpha. During suspension of respiration, 15 mCi of Xe-133 were injected intravenously, and perfusion and equilibration lung images were recorded with a scintillation camera. The procedure was performed several times on each dog, with and without pharmacological elevation of PA pressure by 5 to 50 cm H2O. For each scintigram, the relative blood flow per unit ventilated lung volume (F) was plotted against centimeters above the hilum (h). Pulmonary arterial pressure was derived from each curve, assuming the relation F = B(Pa - hD)2, where B = constant and D = specific gravity of blood. Calculated PA pressure correlated strongly (r = 0.83) with measured PA pressure, suggesting a possible means of noninvasive estimation of PA pressure.
Benign clear-cell tumor of the lung is a rare, distinctive, primary neoplasm with unique histologic and electron microscopic features which may resemble metastatic renal-cell carcinoma. This tumor typically presents as an asymptomatic, peripheral, sharply rounded mass in the lung. Clinical recognition can prevent an unnecessary search for a primary malignant source.
Left ventricular wall motion abnormalities, the extent and location of coronary artery stenoses, and the radiographic evidence of pulmonary venous hypertension were analyzed in a retrospective study of 40 patients who had surgically proven rupture of the interventricular septum after myocardial infarction. In 33 patients in whom chest films were available, interstitial or alveolar pulmonary edema was present in 78%, while left ventricular enlargement was present in 82%. Of 26 patients who had coronary angiography, complete occlusion of the right coronary artery, left anterior descending artery, or left circumflex artery was present in 92%, with few, if any, collateral vessels around the occlusion. The location of the rupture in the muscular septum was always in the region of akinesis or dyskinesis. Posterior defects were associated with posterobasal and diaphragmatic akinesis, and anterior defects with apical akinesis. Left ventricular aneurysms were adjacent to the septal rupture in 68%, and 74% had mitral regurgitation. The right ventricular diaphragmatic wall in posterior rupture was always akinetic, indicating right ventricular infarction. Thus ventricular septal defect after myocardial infarction (1) tends to occur with multiple coronary occlusions about which little collateral flow develops; (2) can accurately be localized anteriorly or posteriorly in the muscular septum by the location of the akinetic left ventricular wall segment; and (3) has an associated right ventricular infarct when rupture is posterior.
Tuberculous mycotic aneurysm has been reported with surprising frequency, especially in the aorta. Because the diagnosis can often be made on clinical and roentgenologic grounds, and because of the very poor prognosis if untreated and surgical curability if recognized, experience with three cases is reported. The aneurysm is generally of the false variety, representing a walled-off perforation of the aorta. Contiguous tuberculosis in the form of lymphadenitis or Pott abscess is generally responsible for the aortic involvement that results in the aneurysm. Miliary tuberculosis, which is often present, is probably a result rather than the cause.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.