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Biomedical subjects

M Brown

Publications and source records attributed to M Brown.

At least 577 records · Page 32Linked to original sources
PubMed1987

Improving survival in patients with cirrhosis undergoing major abdominal operations.

Fifty-one patients with cirrhosis underwent 65 major abdominal procedures, with an 8% mortality and a 28% complication rate. Preoperative and perioperative management was comparable to that rendered patients with cirrhosis undergoing portosystemic shunting procedures. Emergency operation, persistent coagulation defects (prothrombin time and partial thromboplastin time prolonged greater than 2 s), blood loss greater than 4 U, and exploration of the common bile duct were factors associated with increased mortality. Major surgical procedures can be safely performed in critically ill patients with cirrhosis with intensive preoperative care and with minimizing intraoperative blood loss.

Abdomen↗
PubMed1987

Reduced response of cerebral blood flow to hypercapnia: restoration by extracranial-intracranial bypass.

Cerebral blood flow, estimated by the xenon clearance technique, has been used to study eight patients before and after extracranial-intracranial (EC-IC) bypass surgery. Response of cerebral blood flow to hypercapnia was also measured to estimate cerebral reactivity, an indicator of cerebral vasodilator reserve capacity. Measurements in all patients were repeated 3 months after surgery. Resting cerebral blood flow was not increased by the operation but cerebral reactivity in the ipsilateral hemisphere was significantly increased in all patients (P = 0.002). Reactivity also increased in the contralateral hemisphere in six of the eight patients (P = 0.065). The response of cerebral blood flow to hypercapnia may prove useful in the selection of symptomatic patients with carotid occlusions or inaccessible stenoses for revascularization by EC-IC bypass.

Aged↗
PubMed1987

The use of venovenous extracorporeal membrane oxygenation in sheep receiving severe smoke inhalation injury.

Smoke inhalation injury now represents the most frequent cause of death in burn patients, and accounts for 20-80 per cent of overall mortality. We have studied the use of extracorporeal membrane oxygenation (ECMO) to support sheep which have received lethal pulmonary smoke damage. The animals (n = 19) received inhalation injury induced by insufflation with smoke derived from burning cotton delivered with a bee smoker. The treatment group, those placed on ECMO at the time of injury (n=6), were systemically heparinized and placed on a venovenous perfusion circuit consisting of a roller pump, membrane oxygenator and heat exchanger. Blood flow rate in the circuit approximated 20-25 per cent of cardiac output. The animals remained on partial venovenous bypass until the termination of the experiment 96 h after injury. All animals in the treatment group survived. The control sheep (n = 7) received inhalation injury alone and had a 100 per cent mortality (P = 0.0015 ECMO vs. control). Ventilatory management of treatment and control groups followed an identical protocol. We have also studied a third group (n = 6) composed of animals receiving inhalation injury with systemic heparinization but not ECMO. This group had a 66 per cent mortality at 96 h. These studies suggest that partial venovenous ECMO may be a valuable form of adjunctive treatment in severe inhalation injury.

Animals↗
PubMed1987

Change in fibre size, not number, in ageing skeletal muscle.

Skeletal muscle fibre loss and other changes were evaluated in 25 female rats aged 6-24 months. Soleus (SOL) and extensor digitorum longus (EDL) muscles were removed bilaterally. Left SOL and EDL muscles were digested in nitric acid, then, using a dissecting microscope, total fibre numbers for each muscle were obtained. Right muscles were frozen, sectioned and stained with ATPase and alkaline phosphatase to assess fibre-type distribution and capillary number. No significant change in total fibre number was seen with age in either muscle. Atrophy was common after age 12 months but was not found consistently. No reduction in capillary number was observed, even among atrophic fibres. Results suggest that atrophy and not fibre loss, per se, occurs with ageing and that atrophy is not due to capillary loss.

Aging↗
PubMed1987

Effect of pulsed short wave diathermy on skeletal muscle injury in rabbits.

The purpose of this study was to determine whether short wave diathermy (SWD) would enhance healing of a skeletal muscle injury. Thirty-two rabbits were divided into the following four groups: Experimental Group 1 (n = 8), which was given SWD twice daily for 8 consecutive days; Control Group 1 (n = 8), which was followed for 8 days but not given treatment; Experimental Group 2 (n = 8), which was given SWD twice daily for 16 consecutive days; and Control Group 2 (n = 8), which was followed for 16 days but not given treatment. The muscle injury was induced by giving all 32 rabbits three local injections of a myotoxic drug into the right gastrocnemius muscle. After the 8 or 16 days, all muscles were removed, then embedded in paraffin or frozen, sectioned, stained with adenosine triphosphatase or hematoxylin and eosin and examined with a light microscope. No statistically significant differences in the degree of muscle healing were found between the animals in Experimental Group 1 and Control Group 1 and those in Experimental Group 2 and Control Group 2. A trend toward faster resolution of the muscle injury was observed among those rabbits in Experimental Group 2 as compared with those rabbits in Control Group 2. Further study is required to determine whether SWD can be more effective for enhancing recovery from skeletal muscle injury.

Animals↗
PubMed1987

Effects of high voltage stimulation on cutaneous wound healing in rabbits.

The primary purpose of this study was to determine whether high voltage stimulation (HVS) enhances wound healing. Forty female rabbits were assigned to experimental or control groups and followed for four or seven days. We classified the groups as Exp4, Con4, Exp7, and Con7, respectively. Each animal was anesthetized, and a full-thickness incision, 3.5-cm long, was made on its back. After 24 hours, Exp4 and Exp7 rabbits received HVS with a negative polarity for two hours twice daily. Although tensile-strength values were 36% higher for Exp4 rabbits than for Con4 rabbits, no significant differences in tensile strength or percentage of wound closure existed between the two groups. After seven days, Con7 rabbits had a higher percentage of wound closure and significantly greater tensile-strength measures than Exp7 rabbits. Histologic examination of the wounds did not provide clear-cut evidence of differences between the experimental and control groups. Results suggest that 1) HVS did not significantly improve wound healing for Exp4 rabbits and 2) HVS as given, may have hampered the healing process for Exp7 rabbits.

Animals↗
PubMed1987

Clinical reliability of manual muscle testing. Middle trapezius and gluteus medius muscles.

The purposes of this study were to develop a protocol to examine the reliability of manual muscle testing in a clinical setting and to use that protocol to assess the interrater reliability of manually testing the strength of the middle trapezius and gluteus medius muscles. One hundred ten patients with various diagnoses participated as subjects, and 11 physical therapists participated as examiners in this study. The results showed that interrater reliability for right and left middle trapezius and gluteus medius muscles was low. The percentage of therapists obtaining a rating of the same grade or within one third of a grade ranged from 50% to 60% for the four muscles. This study indicates that using manual muscle testing to make accurate clinical assessments of patient status is of questionable value.

Adolescent↗
PubMed1987

An immunohistochemical study of fibronectin in human osteoarthritic and disease free articular cartilage.

Fibronectin is a minor component of cartilage connective tissue matrix, which is reported to accumulate in increased amounts in osteoarthritis. The presence of raised levels of fibronectin in human osteoarthritic cartilage by immunoperoxidase localisation is confirmed. Residual femoral head articular cartilage from 17 patients with osteoarthritis contained variable but substantial amounts of fibronectin. This was localised mainly in a band within the matrix of the surface zone. No significant deposits of fibronectin were found in this or any other area of the normal specimens. Intracellular fibronectin was identified in some cells of the surface zone, indicating that it was, in part, synthesised locally. The presence and distribution of locally produced fibronectin in osteoarthritic cartilage suggest that its synthesis is a response by chondrocytes to changes in the cartilage matrix.

Aged↗
PubMed1987

Delineation of myocardial oxygen utilization with carbon-11-labeled acetate.

Although positron-emission tomography (PET) with labeled fatty acid delineates infarct size and permits qualitative assessment of fatty acid utilization, quantification of oxidative metabolism is limited by complex alterations in the pattern of utilization of fatty acid during ischemia and reperfusion. Because metabolism of acetate by myocardium is less complex than that of glucose or palmitate, we characterized kinetics of utilization of radiolabeled acetate in 37 isolated rabbit hearts perfused with modified Krebs-Henseleit buffer and performed a pilot tomographic study in man. Results of initial experiments with carbon-14-labeled acetate (14C-acetate) indicated that the steady-state extraction fraction of acetate averaged 61.5 +/- 4.0% in control hearts (n = 4), 93.6 +/- 0.9% in hearts rendered ischemic (n = 4), and 54.8 +/- 4.0% in hearts reperfused after 60 min of ischemia (n = 3). Oxidation of 14C-acetate, assessed from the rate of efflux of 14CO2 in the venous effluent, correlated closely with the rate of oxygen consumption under diverse metabolic conditions (r = .97, p less than .001). In addition, no significant differences were observed between rates of efflux of total 14C in all chemical species (reflecting total clearance of tracer from myocardium) and efflux of 14CO2. Clearance of 11C-acetate, measured externally with gamma probes in normal and ischemic myocardium, correlated closely with clearance of 14C-acetate measured directly in the effluent (r = .99, p less than .001) and with overall myocardial oxygen consumption (r = .95, p less than .001). Accumulation and clearance of 11C-acetate from human myocardium with PET demonstrated kinetics comparable to those seen with radiolabeled acetate in vitro. Thus externally detectable clearance of 11C-acetate provides a quantitative index of myocardial oxidative metabolism despite variation in the patterns of intermediary metabolism that confounds interpretation of results with conventionally used tracers such as glucose and fatty acid.

Acetates↗
PubMed1987

Low back pain in Paget's disease of bone.

Clinical and laboratory evaluation with bone scan, radiography, and computed tomography were performed on 25 patients with severe Paget's disease of bone and low back pain. Back pain was classified as caused by Paget's disease in only three patients. The remaining 22 patients had coexistent Paget's disease and osteoarthritis. There was difficulty separating the cause of back pain in those patients with coexistent Paget's disease and osteoarthritis, even when the diseases were present at different levels of the spine. The pathogenesis of Paget's disease appears to precipitate osteoarthritis and several low back syndromes. Suppressive therapy with disodium etidronate (EHDP) for Paget's disease was of benefit in eight of 22 patients (36%) with identifiable osteoarthritis. It is suggested that EHDP and perhaps other suppressive agents for Paget's disease receive limited use in patients with back pain unless a defined pagetic lesion appears related to the clinical syndrome in the absence of identifiable osteoarthritis.

Back Pain↗
PubMed1987

Unhandicapping the disabled: what is possible?

Activity pattern data from a matched sample of 22 able-bodied and 22 spinal cord injured (SCI) men were used to determine the relationship between handicapping conditions (poor access to transportation, low income) and disability. Most subjects were highly educated, earned good incomes, and could be characterized as having adequate resources to achieve a good standard of living. Activity Pattern Indicators reveal that this high-resource SCI group allocated time in a pattern very similar to that of the high-resource, nondisabled group. Significantly less time was spent in active recreation and household tasks. Although the overall time allocation pattern was similar, the groups differed in the tempo of activity entry. The average member of the SCI group switched from one activity to another 20% less often. The findings are discussed in terms of the need for further research and the implications of these findings and of the general approach for a public policy regarding reducing external handicapping conditions. The conclusion is reached that adequate access to resources decreases the impact of impairment in SCI.

Activities of Daily Living↗
PubMed1987

Impact of impairment on activity patterns of children.

The effects of impairment on children's patterns of daily activity were studied. Activity Pattern Indicator diary data were used to document typical daily activities of 239 children with disabilities (mostly spina bifida and cerebral palsy) and 519 nondisabled children. Activities of the two groups were compared using analysis of covariance techniques. The daily life of children with disabilities had less variety and a slower tempo, with more time being spent in dependent activities, quiet recreation, and personal care, and with less participation in social engagements, active recreation, household tasks, and activities away from home. Their activities were, however, more often associated with concurrent social input. Although statistically significant differences in activity were found, the size of differences were minor to moderate, except for indicators of dependence. Age was the covariate most strongly affecting activity. Results indicate similar developmental patterns for the two groups, but children with disabilities had less involvement with education and increased TV viewing with increasing age.

Activities of Daily Living↗
PubMed1987

Significance of thyroid dysfunction in human cardiac allograft procurement.

Twenty-two potential cardiac allograft donors had evaluation of thyroid function performed just prior to cardiectomy. Despite statistically significant abnormal thyroid function, no correlation to graft function or failure was observable. Multiple myocardial microinfarcts, undetected at the time of donor selection were detected in two hearts that were abandoned prior to transplantation and possibly another heart that failed as an allograft in a heart-lung transplant recipient.

Adolescent↗