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Biomedical subjects

R Brown

Publications and source records attributed to R Brown.

At least 739 records · Page 41Linked to original sources
PubMed1981

A negative serological relationship between cases of grass sickness in Scotland and Clostridium perfringens type A enterotoxin.

In an attempt to compare the equine grass sickness as reported in Europe with that described in the Republic of Colombia, sera from horses experiencing grass sickness in Scotland were used in neutralisation tests with Clostridium perfringens type A enterotoxin. The sera, from acute and chronic cases of the disease, failed to neutralise either crude or partially-purified enterotoxin. Neither were precipitin lines formed when the sera were treated against the toxin in immunoelectrophoresis. These results suggest that grass sickness in Europe and the equine disease in Colombia have a different aetiology.

Animals↗
PubMed1981

Diaphragm electrical activity during negative lower torso pressure in quadriplegic men.

We recorded the diaphragm electromyogram (EMG) of quadriplegic men before and during exposure of the lower torso to continuous negative pressure, which caused shortening of the inspiratory muscles by expanding the respiratory system by one tidal volume. The moving-time-averaged diaphragm EMG was larger during expansion of the respiratory system. When we repeated the experiment with subjects who breathed through a mouthpiece, we found qualitatively similar EMG changes and little or no change in tidal volume or end-tidal CO2 partial pressure. When the pressure was applied or removed rapidly, changes in EMG occurred within one or two breaths. Because end-tidal CO2 partial pressure did not increase, and because the response was rapid, we suggest that the response results from proprioceptive, rather than chemoreceptive, reflexes. As most of these men had complete spinal lesions at C6 or C7 the afferent pathways are likely to be vagal or phrenic.

Adult↗
PubMed1981

The effects of large negative intrathoracic pressure on left ventricular function in patients with coronary artery disease.

Using first-pass radionuclide ventriculography, we evaluated the effects of decreases in intrathoracic pressure (Mueller maneuver [M] to -20 to -30 cm H2O) in 14 patients with five patients without coronary artery disease (CAD) and in 12 normal control subjects. In the patients with CAD, control ejection fraction was 0.53 +/- 0.06 (SEM) and control heart rate was 83 +/- 6 beats/min. These did not change during M. In the patients with CAD, control ejection fraction was 0.37 +/- 0.03 and heart rate was 82 +/- 7 beats/min. During M, heart rate did not change, but ejection fraction decreased to 0.33 +/- 0.33 (p less than 0.01). Examination of regional wall motion abnormalities showed akinesis of at least one myocardial segment in nine of 14 patients with CAD, but in none of the patients without CAD, nor in any of the 12 previously studied normal subjects (retrospectively analyzed). These data are consistent with the hypothesis that the Mueller maneuver acts to increase afterload placed on the left ventricle. Furthermore, in patients with CAD, the Mueller maneuver may have induced localized myocardial ischemia or unmasked areas of preexisting marginal function.

Aged↗
PubMed1981

Normal immunoregulation of in vitro antibody secretion in autoimmune thyroid disease.

Defective suppressor cell function may be a causative factor in autoimmune disease in animals and man. In autoimmune thyroid disease, decreased suppressor cell activity could, under appropriate conditions, account for excess production of thyroid autoantibodies. We evaluated suppressor cell function in patients with Graves' disease and Hashimoto's thyroiditis and in normal controls. The method used is based on the principle that immunoglobulin synthesis by pokeweed mitogen (PWM)-stimulated lymphocytes is inhibited by Concanavalin A (Con A) stimulation of suppressor T cells. We studied suppressor cell control of polyclonal immunoglobulin G (IgG) and the thyroid-specific autoantibody, antimicrosomal antibody. PWM-stimulated IgG secretion (mean +/- SD) by lymphocytes from patients with Graves' disease (2797 +/- 718 ng/ml) and Hashimoto's thyroiditis (2201 +/- 423 ng/ml) did not differ from normal subjects (2431 +/- 485 ng/ml). The addition of Con A to PWM-stimulated lymphocytes suppressed IgG production in all three groups: Graves', 475 +/- 137 ng/ml; Hashimoto's, 507 +/- 74 ng/ml; and normal subjects, 460 +/- 156 ng/ml. The degree of suppression by the disease groups did not differ from the normal controls. Antimicrosomal antibody was detected in the concentrated, PWM-stimulated culture media of two of four Hashimoto's lymphocytes, three of five Graves' lymphocytes, and none of nine normal controls. Con A induced marked suppression of this organ-specific antibody in all cases. We conclude that Con A-stimulated lymphocytes from patients with Hashimoto's thyroiditis and Graves' disease can suppress antimicrosomal antibody and polyclonal IgG synthesis. These findings do not support the postulate of a generalized defect of suppressor cell function in these thyroid disorders.

Adult↗
PubMed1980

A comparative study of the ototoxicity of gentamicin and gentamicin C1.

Dose-response experiments comparing the ototoxic liability of the aminoglycoside antibiotics gentamicin sulfate and gentamicin C1 sulfate were conducted on guinea pigs. Measures of cochlear electrophysiology, histology, and the pharmacokinetic disposition of the drugs in the plasma and perilymph were made. Electrophysiological and histological measures indicated that gentamicin is more ototoxic than is gentamicin C1.

Animals↗
PubMed1980

Laser therapy of rheumatoid arthritis.

Thirty people with classical or definite rheumatoid arthritis received laser exposure to a Q-switch neodymium laser that operated at 1.06 micrometer with an output of 15 joules/cm2 for 30 nsec. One hand was lased at the proximal interphalangeal (PIP) and metacarpal phalangeal (MCP) joints, whereas the other hand was sham lased. The patient, physician, and occupational therapy evaluators did not know which hand was being lased. Twenty-one patients noted improvement of both their MCP and PIP joints of both hands during laser therapy. Twenty-seven noted improvement of their PIP joints and 26 noted improvement of the MCP joints during therapy. Heat, erythema, pain, swelling, and tenderness all improved with time in both hands, but the lased hand had more significant improvement in erythema and pain. There was also significant improvement in grasp and tip pressure on the lased side. The level of circulating immune complexes as measured by platelet aggregation decreased during lasing. The improvement may be related to laser exposure. The exact role that laser radiation has upon rheumatoid arthritis and its mechanism of action remain to be elucidated.

Adult↗
PubMed1980

Assignment to chromosome 16 of a gene necessary for the expression of human mitochondrial glutamate oxaloacetate transaminase (aspartate aminotransferase) (E.C. 2.6.1.1.).

A gene necessary for the expression of human mitochondrial glutamate oxaloacetate transaminase (GOT-2) has been assigned to chromosome 16 on the basis of an immunochemical analysis of human-mouse somatic cell hybrids. Mitochondrial GOT cosegregates with adenine phosphoribosyl transferase (E.C. 2.4.2.7.).

Adenine Phosphoribosyltransferase↗
PubMed1980

Spontaneous cure of infected left atrial myxoma following embolization.

A patient with prolonged duration, bacterial infection, and echocardiographic disappearance of an atrial myxoma following embolization is discussed. Following aortic saddle embolus, all echocardiographic manifestations of the patient's left atrial myxoma disappeared. Previous cases of infected atrial myxomas are reviewed. The necessity of early surgical intervention, despite active infection, is discussed.

Embolism↗
PubMed1980

Renal function in critically ill postoperative patients: sequential assessment of creatinine osmolar and free water clearance.

Sequential assessment of renal function in 50 critically ill postoperative patients was done by simultaneous determinants of osmolar, free water, creatinine and sodium clearances, and fractional excretion of sodium. The traumatic and nontraumatic critically ill surgical patients had a characteristic pattern of creatinine clearance (Ccr) which was age related. This was manifested in the trauma patient by Ccr which were initially greater than expected (140-190 ml/min.1.73 M2). In the uncomplicated postoperative patients, a positive correlation was found between increased cardiac index and the indexed glomerular filtration rate. Decreases in free water clearance and Ccr were useful in predicting the onset of renal failure before the development of the oliguric state. The authors conclude that frequent assessment of those renal functions which are most adversely affected by accidental or surgical trauma is most appropriately monitored by serial measurement of creatinine and free water clearance.

Acute Kidney Injury↗
PubMed1980

A scheme for the identification of clinical isolates of Gram-negative anaerobic bacilli by conventional bacteriological tests.

More than 1000 strains of gram-negative anaerobic bacilli, including reference strains, clinical isolates, and members of the normal flora of the mouth, lower gastro-intestinal tract and vagina of healthy human subjects, were studied by conventional bacteriological methods and by gas-liquid chromatographic analysis of metabolic products in a series of investigations. A short combined set of tests with particular discriminant value was selected, and a scheme for the identification of the species and subspecies encountered in the diagnostic bacteriological laboratory was based upon our composite results. The tests are: antibiotic-disk resistance tests with neomycin 1000 micrograms, kanamycin 1000 micrograms, penicillin 2 units and rifampicin 15 micrograms per disk; tolerance tests with sodium taurocholate, Victoria blue 4R and gentian violet; and tests for pigment production, indole production, aesculin hydrolysis and the fermentation of glucose, lactose, sucrose, rhamnose, trehalose, mannitol and xylose. Gram-negative anaerobic bacilli are divided into four groups: (1) the fragilis group with nine species, which include the five subgroups previously classified as subspecies of B. fragilis; (2) the melaninogenicus-oralis group, which includes the three saccharolytic subspecies (ss.) of B. melaninogenicus--ss. melaninogenicus, ss. intermedius and ss. levii--and four non-pigmented species; (3) the asaccharolytic group, which comprises B. asaccharolyticus (formerly B. melaninogenicus ss. asaccharolyticus), B. corrodens and other non-pigmented non-saccharolytic strains, and (4) the fusobacteria.

Anti-Bacterial Agents↗
PubMed1980

Campylobacter enteritis in Chelmsford.

During one year, out of 1829 faecal specimens examined at the Chelmsford Public Health Laboratory, campylobacters were isolated from 109 (6%), 21 of the positive cultures were from hospital in-patients and 3 were from hospital staff. The remaining 85 isolates were from specimens sent in by general practitioners. The authors' figures show a marked season variation with most of the infections occurring from June to September. The highest incidence (36%) was in the 20 to 30 age group, 99% of patients had diarrhoea, usually watery, occasionally explosive, and 9% had visible blood in their stools. Eighteen per cent. of patients had abdominal pain, 5 of the 21 hospital in-patients underwent abdominal surgery. Fifty-nine faecal specimens were examined microscopically and 30 of these had blood and pus cells or pus cells alone. Three patients had rectal biopsies showing a nonspecific colitis, 11 patients had recently been abroad.

Adolescent↗