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Biomedical subjects

J F Murray

Publications and source records attributed to J F Murray.

At least 127 records · Page 7Linked to original sources
PubMed1983

Post-traumatic dystrophy of the extremities.

A series of 126 patients who had post-traumatic dystrophy of the hand and foot, with a follow-up of more than five years in most, is described. Nearly all had continuing symptoms and signs. An additional twenty-seven patients, with twenty-eight involved extremities, who were referred from various hospitals in Toronto were treated with one or more intravenous injections of a solution of lidocaine and corticosteroid followed by standard physical therapy. The results were satisfactory or better in twenty-one extremities and poor in seven. Of the twenty-one with a satisfactory result, eleven (six patients with involvement of the hand, bilateral in one, and four patients with involvement of the foot) had an excellent result while the other ten showed substantial improvement. The most important factor in predicting improvement with treatment was a short interval (less than six months) between the onset of dystrophy and the administration of therapy.

Aged↗
PubMed1983

Disposition of prothionamide in rats and armadillos.

A new method for the sensitive and selective measurement of prothionamide (PTH) and its S-oxide metabolite (PTHSO) in biological fluids was described. The limit of sensitivity was approximately 0.01 microgram of drug/ml of plasma. Endogenous materials, 2-propylisonicotinamide, ethionamide, dapsone, or monoacetyl dapsone did not interfere or contribute. Rats receiving PTH, intravenously or orally, showed a sexual dimorphism in the ability to oxidize PTH to PTHSO, with males exhibiting greater capacities for this conversion. Both sexes cleared the administered PTH more rapidly from the plasma than the metabolite, PTHSO. Following oral or intravenous administration of equimolar doses of PTHSO, both sexes exhibited an ability to reduce the administered PTHSO to PTH, with the female showing greater capacities for this conversion. Clearances after oral PTHSO administration were again more rapid for PTH than for PTHSO in both sexes. However, the total of PTH and PTHSO in the plasma during 8 hr following PTHSO administration was consistently less than following PTH dosing. Therefore, although PTHSO is retained longer than PTH after either PTH or PTHSO administration, giving PTHSO yielded less total active drug in the circulation. Comparison of plasma patterns of PTH and PTHSO in unfasted rats receiving one oral or eight daily oral doses of PTH did not indicate that PTH induces its own metabolism. Limited studies in armadillos receiving PTH and PTHSO intravenously led to the same general conclusions as those we derived from the rat studies regarding the disposition of PTH and PTHSO.

Animals↗
PubMed1983

Mutagenic activity of antileprosy drugs and their derivatives.

We tested the mutagenic activity of antileprosy drugs (clofazimine, ethionamide, prothionamide, prothionamide-S-oxide, rifampin, and dapsone and many of its derivatives) using the Ames Salmonella/microsome assay system. None of these, including N-acetylated and N-hydroxylated derivatives of dapsone, were found to be positive with or without metabolic activation of this test. However, the sulfoxide and sulfide analogs of dapsone were found to be mutagenic with metabolic activation. These two analogs could not be detected in pharmaceutical preparations of dapsone (less than 0.01%), nor could they be found (in either unconjugated or conjugated form) in urine from volunteers taking a single oral dose of 50 mg of dapsone or from patients receiving daily oral doses of 100 mg of dapsone. Also, urine concentrates from volunteers taking 50 mg of dapsone did not exhibit mutagenic activity in the Ames screen. These results indicate that patients receiving antileprosy therapy with clofazimine, dapsone, ethionamide, prothionamide, and/or rifampin are not being exposed to mutagenic (and thereby possible carcinogenic) drugs.

Clofazimine↗
PubMed1982

Leiomyoblastoma of the omentum. A case report.

Leiomyoblastoma is an uncommon tumour derived from smooth-muscle cells. A leiomyoblastoma presenting apparently as an omental tumour, as in the case presented, is exceptionally rare. Special mention is made of the value of the left decubitus position in computed tomography scanning for omental and mesenteric masses.

Angiography↗
PubMed1982

Uneven driving pressures and redistribution of intrapulmonary blood flow.

Pulmonary arterial pressure (Ppa) and airway pressure (Paw) change equally when Paw varies widely in normal lungs under zone 2 conditions. To evaluate the mechanism underlying the decrease in Ppa at a given Paw in edematous lungs, we measured the quantity of right-to-left shunting of blood (Qs/QT) with sulfur hexafluoride (SF6) using in situ perfused dog lungs from five control animals, five animals with bronchial occlusion, and eight animals with oleic acid-induced pulmonary edema. Under base-line conditions when positive end-expiratory pressure (PEEP) was increased from 5 to 15 cmH2O, Ppa increased because Paw was fully transmitted to Ppa. After bronchial occlusion at 5 cmH2O PEEP, observed QS/QT was less than predicted (P less than 0.01) on the basis of regional conductances, but at 15 cmH2O observed and predicted QS/QT did not differ (P greater than 0.5). In five of eight dogs with oleic acid-induced pulmonary edema. QS/QT increased when PEEP was increased. We conclude that pressure barriers that create nonuniform driving pressures cause a decrease in Ppa and a redistribution of blood flow.

Animals↗
PubMed1982

Effect of different levels of positive end-expiratory pressure on lung water content.

To compare the effects of 2-, 5-, and 10-cmH2O positive end-expiratory pressure (PEEP) on pulmonary extravascular water volume (PEWV), pulmonary blood volume (PBV), pulmonary dry weight (PDW), and distensibility, we separately ventilated perfused dogs' lungs in situ and produced pulmonary edema with oleic acid (0.06 ml/kg). Three groups were studied: I, PEEP, 5 cmH2O in both lung; II, PEEP, 2 cmH2O in one lung and 10 cmH2O in the other; and III, PEEP, same as II, but the chest was rotated to compensate for differences in heights. The PEWV and distensibility were less (P less than 0.05) in lungs exposed to 10-cmH2O than to either 2- or 5-cmH2O PEEP. After chest rotation, the difference between 10- and 2-cmH2O PEEP on PEWV was eliminated but that on distensibility was not. We conclude that 10-cmH2O PEEP 1) decreased water content because of lung volume-induced effects on intravascular hydrostatic pressure and 2) improved distensibility by recruitment of alveoli, irrespective of PEWV.

Animals↗
PubMed1982

Construction of a stabilometer capable of indicating the variability of non-level performance.

Construction and validation of a stabilometer as a measure of gross motor balance was achieved by using a stabilometer designed to provide a quantitative score sensitive to variability of performance in a non-horizontal position. Reliability was obtained through test-retest and by mechanically manipulating the instrument. Validity was indicated by content and construct validity techniques. Both reliability and validity were high, and the instrument was viewed as appropriate for measuring gross motor balance.

Humans↗
PubMed1981

Continuous positive-pressure ventilation does not alter ventricular pressure-volume relationship.

To determine whether alterations in the mechanical properties (i.e., stiffening) of the right and left ventricles contribute to the decrease in right and left ventricular end-diastolic volumes during continuous positive-pressure ventilation (CPPV), we studied six dogs anesthetized with chloralose urethane and ventilated with a volume ventilator. We varied ventricular volumes by withdrawing or infusing blood. Pressure-volume curves, constructed by plotting transmural ventricular end-diastolic pressures against ventricular end-diastolic volumes, did not change during CPPV (12 cmH2O positive end-expiratory pressure) compared to intermittent positive-pressure ventilation (IPPV, 0 cmH2O end-expiratory pressure). We conclude that decreased ventricular end-diastolic volumes during CPPV result primarily from a decrease in venous return. Alterations in the mechanical properties of the ventricles do not play a significant role in this response.

Animals↗
PubMed1981

Interactions between permeability and hydrostatic pressure in perfused dogs' lungs.

To evaluate interactions between increased permeability of the pulmonary vasculature and increased hydrostatic pressure on lung fluid flux, we measured water and blood contents of five equally thick slices of in situ perfused dogs' lungs that had been vertically suspended and, after experimental manipulations, rapidly frozen. Measurements were made under four sets of conditions (4 dogs each): 1) control; 2) increased left atrial pressure (Pla), 25 cmH2O relative to the bottom of the lung; 3) oleic acid; and 4) oleic acid and increased Pla. Significant interactions on lung water content were found between 1) oleic acid and increased Pla (P less than 0.005) and 2) oleic acid and height of the slice of lung (P less than 0.003). Blood content was significantly affected by interactions between 1) oleic acid and height of the lung slice (P less than 0.001) and 2) increased Pla and height of the lung slice (P less than 0.001). We conclude that there are significant interactions between increased permeability and hydrostatic pressure that affect regional lung water content and intrapulmonary distribution of blood.

Animals↗
PubMed1981

Assessment of alveolar-capillary membrane permeability of dogs by aerosolization.

We developed a method for measuring an index of alveolar-capillary membrane permeability (PI) by aerosolizing a mixture of 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) and 125I-antipyrine (I-AP) and injecting 111In-DTPA (In-DTPA). The I-AP was used to compute the quantity of Tc-DTPA delivered and the In-DTPA the quantity of Tc-DTPA in the body. The PI was the ratio of the uptake of Tc-DTPA per minute to the amount deposited at the end of aerosolization. In 14 anesthetized dogs we measured the volume of distribution of I-AP (0.54 +/- 0.034 l/kg body wt) and/or showed that the volumes of distribution of Tc-DTPA and In-DTPA were similar. We measured PI in four groups of dogs: control (n = 5), oleic acid (n = 5), hydrochloric acid (n = 6), and high left atrial pressure (n = 5). The PI increased significantly in both groups with acid-induced increased permeability compared with the control and high left atrial pressure groups, which did not differ from each other. We conclude that the aerosolization method is suitable for differentiating increased from normal permeability.

Aerosols↗
PubMed1981

Measurement of pulmonary tissue volume and blood flow in persons with normal and edematous lungs.

We measured pulmonary tissue volume (Vt) and pulmonary capillary blood flow (Qc) by a rebreathing method using two soluble gases, acetylene (C2H2) and dimethyl ether (DME), in 32 normal subjects and 14 patients who had had pulmonary edema. In 18 of the normal subjects, studies were performed at three or more different rebreathing volumes (VA). To normalize for differences in body size, results were expressed as the ratio of Vt or VA to predicted total lung capacity (TLC). We found that 1) changes in VA/TLC had a significant effect on Vt/TLC and Qc measured with both gases, 2) the range of normal values for Vt was best defined by expressing the relationship between Vt/TLC and VA/TLC, 3) using this approach, many patients with clinically mild or inapparent pulmonary edema had abnormal values of Vt, and 4) when comparing mean values of C2H2 and DME in 82 simultaneous measurements at constant VA/TLC, Vt was significantly higher in 87% (71/82) and Qc in 63% (52/82) of the paired tests.

Acetylene↗