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Biomedical subjects

J F Murray

Publications and source records attributed to J F Murray.

At least 145 records · Page 8Linked to original sources
PubMed1981

Dapsone in saliva and plasma of man.

Concentrations of dapsone (DDS) and its metabolite, monoacetyl dapsone (MADDS) were measured in plasma and saliva samples collected concurrently from volunteers receiving a 50-mg oral dose of DDS. A liquid chromatographic technique was employed to separate the compounds from each other and from endogenous materials. Fluorescence detection provided limited sensitivities to 0.1 ng/ml of sample. Saliva levels of DDS were consistently 15-20% of the plasma levels of DDS during the study period, which ranged from 4 to 48 h. Decay rates for DDS from saliva and plasma were nearly identical. In 4-hour samples of plasma subjected to equilibrium dialysis, we found amounts of DDS in the dialysates nearly identical to levels found in saliva collected at that time. Saliva levels of MADDS ranged from 0.8 to 2.6% of their plasma levels at all times. Decay rates of MADDS from the two fluids were nearly identical and saliva levels of MADDS in 4-hour samples were nearly identical to levels found in paired plasma dialysates. Nevertheless, levels of MADDS were so low that a reliable definition of the subjects' acetylator phenotype from levels of MADDS in saliva only was impossible.

Acetylation↗
PubMed1980

The activity-set hypothesis for warm-up decrement in a movement balance task.

This study investigated the activity-set hypothesis in reducing warm-up decrement. With regard to the hypothesis, it is predicted that warm-up decrement, which is a temporary loss of skill performance following rest, could be reduced if an appropriate reinstating activity were engaged in just prior to the resumption of practice. Seventy-five subjects were given twenty 20-sec tests on the stabilo-meter (criterion task), and then either (a) rested, (b) rested and then performed on interpolated "activity-set" task, or (c) rested and then performed an interpolated "activation" task. All subjects, after receiving one of the three conditions were then retested on the stabilometer for an additional six trials. An analysis of planned comparisons showed that the activity-set interpolated task was effective in reducing warm-up decrement and that activation was not a factor.

Journal Article↗
PubMed1980

Rapidly fatal lymphangioma-like Kaposi's sarcoma.

A 34-year-old black South African male was treated for lymphangioma-like clinical Kaposi's sarcoma. The disease followed a rapidly fatal course and was characterized by unexplained recurrent pleural effusions and severe refractory anaemia due to the presence of dilated vascular channels in the bone marrow. Definitive diagnosis was only made at autopsy. Lymphangiomatous changes in the skin without spindle cell formation caused diagnostic difficulties.

Adult↗
PubMed1980

Effects of oleic acid-induced pulmonary edema on lung mechanics.

In 25 rabbits anesthetized with pentobarbital sodium and paralyzed with succinylcholine chloride, we investigated the contributions of four factors that might cause the decreased static lung compliance found in oleic acid-induced pulmonary edema: 1) foam, 2) accumulation of fluid in the interstitial spaces, 3) loss of ventilatable units secondary to alveolar flooding, and 4) increased surface tension. Pulmonary edema, reflected by a 115% increase in mean post-mortem extravascular bloodless lung water content, decreased compliance 47% and tripled alveolar-arterial PO2 difference. Removing foam by degassing did not affect compliance measurements. Filling the lungs with saline caused similar changes in control and edematous animals. Because the 38% decrease in functional residual capacity was largely attributable to water accumulation, we concluded that loss of ventilatable units accounted for virtually all the decreased static lung compliance. The role of increased surface tension could not be determined directly but was considered relatively less important.

Animals↗
PubMed1980

Continuous positive-pressure ventilation decreases right and left ventricular end-diastolic volumes in the dog.

We investigated the mechanism(s) responsible for the decreased cardiac output during continuous positive-pressure ventilation (CPPV). Seven dogs were anesthetized with chloralose-urethane, intubated, and ventilated using a volume ventilator. We measured heart rate, stroke volume, and the determinants of stroke volume: left and right ventricular end-diastolic volumes, isovolumic and ejection phase indices of myocardial contractility, and pulmonary and systemic arterial pressures. Myocardial blood flow was estimated using radioactive microspheres. Variables were measured during a control period of intermittent positive-pressure ventilation (IPPV), 8-20 minutes after the initiation of CPPV using 12 cm H2O positive end-expiratory pressure (PEEP), and 8-20 minutes after the removal of PEEP. CPPV decreased cardiac output but did not affect total or regional myocardial blood flow or the ratio of subendocardial to subepicardial blood flow. Isovolumic and ejection phase indices of myocardial cointractility, heart rate, and systemic arterial pressure did not change during CPPV. Right and left ventricular end-diastolic and end-systolic volumes decreased markedly during CPPV. We conclude that CPPV decreases cardiac output in accordance with Starling's law by decreasing preload.

Animals↗
PubMed1979

The value of edema fluid protein measurement in patients with pulmonary edema.

Alveolar fluid and plasma proteins were analyzed in 24 patients with florid pulmonary edema, in 21 of whom pulmonary capillary wedge pressure (Pcw) was also measured. In all patients with Pcw less than 20 mm Hg, the edema fluid to plasma protein ratio exceeded 0.6; the mean edema fluid to plasma protein ratio in the four patients with cardiogenic edema (increased Pcw) was 0.46. In the 21 patients in whom full data were available, the net intravascular filtration force (Pcw - plasma colloid osmotic pressure) was less than -4 mm Hg, the value at which (according to others) pulmonary edema should occur, in only 10. When the interstitial colloid osmotic pressure, approximated by the osmotic pressure of edema fluid protein, was added, the net filtration force became positive in 17 of 21 patients. Comparison of the protein concentrations of edema fluid and plasma aids in the diagnostic separation of increased permeability from high hydrostatic pressure edema and adds to our understanding of the relative osmotic and hydrostatic forces that contribute to pulmonary edema when the alveolar-capillary membrane is damaged.

Adolescent↗
PubMed1979

Proficiency testing in immunohematology in Ontario, Canada, 1975-1977.

Since April 1975 the proficiency of laboratories in Ontario that perform immunohematology tests has been assessed. While the majority of test samples have required only ABO and Rh(D) typing, others have posed problems. The error rate in uncomplicated ABO typing was 1.3/1,000 in 17,479 tests and that in straightforward Rh(D) grouping, 6.6/1,000 in 17,757 tests. False-negative (36/1,000) and false-positive (1.4/1,000) direct antiglobulin tests occurred. Errors in detection of strong alloantibodies (e.g., anti-D) were 19.7, 10.2 and 5.1/1,000 in three test samples. A2B or A2 cells with anti-A1 in serum were sent out in two surveys; error rates in ABO interpretation were 189 and 52/1,000, respectively. Laboratories also experienced difficulty in interpreting the Rh(D) type of cells with positive antiglobulin tests. These surveys have had several effects: (1) laboratories with poor performance have been identified, (2) patterns of practice have been influenced, (3) areas of ignorance have been identified, and (4) a stimulus has been provided for continuing education in immunohematology.

ABO Blood-Group System↗
PubMed1979

Measurement of pulmonary edema in intact dogs by transthoracic gamma-ray attenuation.

We evaluated the attenuation of the 122 keV gamma ray of cobalt-57 across the thorax of anesthetized dogs as a method for following the time course of lung water changes in acute pulmonary edema induced by either increased microvascular permeability or increased microvascular hydrostatic pressure. The gamma rays traversed the thorax centered on the seventh rib laterally where the lung mass in the beam path was greatest. Calibration measurements in isolated lung lobes demonstrated the high sensitivity and inherent accuracy of the method over a wide range of lung water contents. In control dogs reproducibility averaged +/-3%. Increased permeability edema led to large rapid increases in the transthoracic gamma ray attenuation (TGA), while increased pressure caused an immediate, modest increase in TGA (vascular congestion) followed by a slow further increase over 2 h. There was a fairly good correlation between the increase in extravascular lung water and the change in TGA. The method is simple, safe, and noninvasive and appears to be useful for following the time course of lung water accumulation in generalized lung edema in anesthetized animals.

Animals↗
PubMed1979

Evaluation of transthoracic electrical impedance in the diagnosis of pulmonary edema.

To evaluate the clinical usefulness of measuring transthoracic electrical impedance in patients with pulmonary edema, we studied 27 normal subjects and 33 patients. In normal subjects, impedance increased when body position changed from supine to standing (p less than 0.01) and when lung volume increased from residual volume to total lung capacity (p less than 0.01). Impedance values vari7 omega) when measured hourly without removing the electrodes. In only five of 11 patients with clinically severe pulmonary edema and five of eight with radiologically severe pulmonary edema were impedance values outside the normal range. Changes in impedance values correlated with changes in clinical and radiographic indexes of pulmonary edema. We conclude that (1) single measurements of impedance are useless in diagnosing pulmonary edema, and (2) impedance changes as predicted as pulmonary edema increases and decreases, and these changes are readily detected by simpler methods of evaluation.

Adult↗
PubMed1978

Hyperpyrexia of uncertain origin.

Hyperpyrexia occurring in a 27-year-old woman undergoing eye surgery is described. The cause, although open to doubt, appeared to be a thyroid storm.

Adult↗
PubMed1978

Effects of lung inflation on pulmonary arterial pressure in dogs with pulmonary edema.

The effects of lung inflation from positive airway pressure (Paw) on pulmonary arterial pressure (Ppa) and the slope deltaPpa/deltaPaw were studied in normal dogs and dogs with pulmonary edema. Under base-line zone 2 conditions with the lungs perfused at constant flow (100 ml/kg per min) and vascular pressures measured relative to pleural (atmospheric) pressure, the slope deltaPpa/deltaPaw was nearly one (at Paw greater than or equal to 5 cmH2O). Pulmonary edema from high capillary pressure and oleic acid caused deltaPpa/deltaPaw and Ppa to decrease at high lung volumes and Ppa to increase at low lung volumes. These changes were not simulated by vasoactive drugs (adenosine and norepinephrine) but were reproduced by instilling dextran into the lungs and, in part, by occluding the right intermediate bronchus. In pulmonary edema the increased Ppa at low lung volumes is caused by the effects of decreases in the caliber of extra-alveolar vessels, by trapped air or liquid raising alveolar pressure, or by both; the decreased deltaPpa/deltaPaw and Ppa at high volumes is caused mainly by nonuniform distribution of driving pressures and blood flow.

Adenosine↗
PubMed1977

Transmetacarpal amputation of the index finger: a clinical assessment of hand strength and complications.

A clinical study of hand strength and complications in 41 patients with a transmetacarpal amputation of the index finger found that the average prehension strength was reduced by 20% and stability of grip by almost 50%. Tendon transfers or other operative modifications did not affect the results. The most disabling complication, hyperesthesia, or painful sensitivity to light touch, in the thumb--long-finger web was present in 59% of patients and interfered with hand function in 37%.

Adolescent↗