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Biomedical subjects

M Walker

Publications and source records attributed to M Walker.

At least 523 records · Page 29Linked to original sources

Metabolic effects of adrenaline and noradrenaline in man: studies with somatostatin.

The metabolic responses to infusion of adrenaline (6 micrograms/min) and of noradrenaline (5 micrograms/min) for 120 minutes have each been studied in five normal males with and without concurrent somatostatin (250 micrograms/h). Adrenaline induced marked and sustained hyperglycaemia (maximal blood glucose at 75 min, 9.0 +/- 0.4 mmol/l) while noradrenaline induced only a mild and transient blood glucose rise. Blood lactate was elevated by adrenaline (2.57 +/- 0.47 mmol/l with adrenaline, 0.62 +/- 0.06 mmol/l with saline at 120 min, p less than 0.02). Pyruvate levels rose proportionately less so that the circulating lactate:pyruvate ratio was increased (16.6 +/- 1.3 with adrenaline, 11.4 +/- 0.9 with saline at 120 min, p less than 0.05). Lactate and pyruvate levels were unaffected by noradrenaline. Both catecholamines increased circulating non-esterified fatty acid (NEFA) and glycerol to peak at 30 min, while maximal 3-hydroxybutyrate concentrations were achieved at 50 min (0.26 +/- 0.07 mmol/l with adrenaline; 0.23 +/- 0.06 mmol/l with noradrenaline; 0.03 +/- 0.01 mol/l with saline, both p less than 0.05). Insulin levels were partially suppressed by noradrenaline, while a small rise in circulating insulin was observed with adrenaline which was also associated with a large rebound rise in insulin secretion on cessation of the infusion. Mild and transient hyperglucagonaemia was observed with adrenaline while stimulation of glucagon secretion was more sustained with noradrenaline. Somatostatin suppressed insulin, glucagon and growth hormone secretion and both magnified and prolonged the hyperglycaemic effect of adrenaline (maximal at 105 min, 11.3 +/- 0.5 mmol/l, p less than 0.01 versus adrenaline alone).(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗

Effects of compliance alteration on healing of a porous dacron prosthesis in the thoracic aorta of the dog.

In our study, the results reveal that a marked reduction in the compliance of an external-velour, weft-knit Dacron prosthesis did not impair healing of either the graft wall or of the anastomoses when these grafts were implanted in the upper part of the descending thoracic aorta of the dog for 56 days. These observations are clinically relevant, since they are important to the design of noncrimped fabric prostheses which are resistant to kink and compression when used for axillofemoral, femoropopliteal and femorotibial bypass. However, experimental studies of the influence of compliance disparity should be extended to such grafts implanted for several years.

Animals↗

Follow-up of subjects in prospective studies based in general practice.

In prospective studies of ischaemic heart disease, data on the incidence of morbidity as well as mortality are critical to the understanding of the natural history of disease. In the Regional Heart Study, 7,735 middle-aged men recruited from general practices in 24 towns in England, Wales and Scotland have been examined, and are being followed for morbidity and mortality for at least five years. This paper explains the methods used and the difficulties encountered in maintaining the flow of information on these subjects and, in particular, discusses the problems of removal and tracing. A network of enquiries, using Family Practitioner Committees, the NHS Central Register and the additional 500 doctors (to date) to whom subjects have transferred, has enabled contact to be maintained. In the first seven towns reviewed at five years from the initial examination, replies have been received from 98 per cent of the original sample still alive and living in Great Britain.

Adult↗

Vertebral osteomyelitis due to coccobacilli of the HB group.

Three cases of pyogenic vertebral osteomyelitis occurred in which unusual, fastidious, Gram negative coccobacilli belonging to the "HB" group were isolated. The organisms were Haemophilus aphrophilus in case 1, intermediate between H aphrophilus and Actinobacillus actinomycetemcomitans in case 2, and Eikenella corrodens in case 3. All HB bacteria are sensitive to a wide range of antibiotics.

Actinobacillus↗

Flow microfluorometry detects IgM autoantibody to oligodendrocytes in multiple sclerosis.

Freshly isolated canine oligodendrocytes were reacted by indirect membrane immunofluorescence with 44 sera from patients with multiple sclerosis (MS). Using analysis by flow microfluorometry (FMF), we found significant IgM antibody binding to the surfaces of oligodendrocytes in the MS sera. The fluorescence intensity of cell surface reactions for MS sera (F.I. greater than 40 = 37.2 +/- 21.34%) was significantly different (P less than 0.001) to that for 53 sera from normal subjects (10.0 +/- 8.97%), 15 sera from patients with Murray Valley encephalitis (6.18 +/- 5.3%), 22 with brain tumours (6.18 +/- 5.3%), 25 with SLE (13.42 +/- 11.65%), 7 with GBS (9.77 +/- 3.9%) and 7 miscellaneous neurological disorders (6.87 +/- 3.04%). Cell surface binding was restricted to oligodendrocytes and was absorbed out by oligodendrocytes but not by liver cells or kidney cells. Oligodendrocytes were identified by conventional histology, phase-contrast optics, electron microscopy (EM) and by cell surface reactions with anti-galactocerebroside, a specific immunocytological marker for oligodendrocytes. A cell sort of the single 0 degree FMF scatter peak followed by EM examination confirmed that the reactive cells consisted exclusively of oligodendrocytes. Viability of oligodendrocytes before and after the staining reactions, was greater than 80% as assessed by trypan blue and fluorescein diacetate exclusion. The possibility that immune reactions mediated by the surface-reactive antibody with readily accessible cell surface autoantigens in vivo may contribute to the loss of oligodendrocytes and demyelination in MS is raised.

Adolescent↗

Scintigraphy in the diagnosis and management of septic sacro-iliitis.

Septic sacro-iliitis is a rare, life-threatening condition. The diagnosis is difficult, both clinically and radiographically, resulting in increased morbidity and delay in treatment. Skeletal scintigraphy is a sensitive method of establishing the diagnosis and monitoring progress. The blood pool image of the bone scan is the most informative part of the investigation.

Adolescent↗

Effects of tap water lead, water hardness, alcohol, and cigarettes on blood lead concentrations.

A survey of middle-aged men in 24 British towns has found pronounced geographical variation in blood lead concentrations. Towns with the highest mean blood lead concentrations have soft water supplies and have the highest water lead concentrations. Individual blood lead can be considerably increased by raised household tap water lead concentrations. Mean blood lead is estimated to be 43% higher for men when the concentration of lead in first-draw domestic tap water is 100 micrograms/l compared with a zero concentration. Individual blood lead is also affected by alcohol consumption and cigarette smoking, such that on average these two life-style habits together contribute an estimated 17% to the blood concentration of lead in middle-aged men. Lead in water should be given greater priority in any national campaign to reduce lead exposure.

Adult↗

Necrotizing fasciitis: the Howard University Hospital experience.

All surgical cases from 1965 to 1980 and autopsy cases from 1974 to 1980 diagnosed at Howard University Hospital as necrotizing fasciitis (NF) were reviewed. Eight patient fulfilled the criteria for NF, which included (1) fascial necrosis, (2) spreading cellulitis with undermining of fascial planes, and (3) systemic toxicity as evidenced by altered mental state and hyperthermia. Bacteroides fragilis was commonly found in our most recent cases. Poor prognostic signs included (1) documented bacteremia, (2) preoperative hypotension (systolic blood pressure lower than 80 mmHg), and (3) hypocalcemia (serum calcium less than 7.0 mg/dL). Therapy consisted of wide debridement with systemic antibiotics and delayed skin grafting when needed.

Aged↗

The prevalence of dysuria in women in London.

A postal questionnaire was used in a survey of dysuria in women aged 20-54 years in four London general practices. Twenty per cent of all women reported dysuria in the previous year (recent dysuria) and half of these women suffered at least one further episode in the same year. The prevalence of recent dysuria showed a decline with increasing age, a small increase with increasing number of pregnancies, no social class effect and no difference with marital status. Frequent recent episodes were more likely in women whose first reported episode of dysuria occurred before the age of 20 years. The risk of dysuria occurring in any pregnancy was about 12 per cent, and a small group - about 6 per cent of those who had had more than one pregnancy - reported dysuria in every pregnancy. Comparison of the practice records of non-responders and responders suggested that the true prevalence of recent dysuria was over-estimated by about one third. The routine use of a few specific questions in clinical and epidemiological practice may help to identify those women at increased risk from urinary tract infection, particularly in pregnancy.

Adult↗

Effects of alcohol and smoking on blood lead in middle-aged British men.

A survey of middle-aged men in 24 British towns showed a strong association between blood lead concentrations, alcohol consumption, and cigarette smoking. The association with alcohol persisted after age, social class, body mass index, cigarette smoking, water lead concentrations, and the town of residence had been taken into account. There was an independent but less pronounced association between cigarette smoking and blood lead concentrations after adjustment for the other factors. The possible mechanisms include a decreased excretion of lead due to alcohol-induced hepatic dysfunction and an increased lead intake from cigarette smoking. These findings have implications for widespread measurement of blood lead concentrations in adults in the community and for all studies attempting to relate blood lead concentrations to environmental exposure.

Adult↗

Pathological correlation of CT ring in recurrent, previously treated gliomas.

The meaning of the enhancing ring commonly seen on computerized tomographic (CT) scans in patients with recurrent, treated glioblastoma has long been of concern. Does the ring represent radiation necrosis, pseudocapsule formation, compressed adjacent brain, or, in fact, a peripheral zone of viable tumor? We employed a multiple intratumoral biopsy technique at the time of reoperation to investigate this ring. Pathological evidence is presented documenting the content of the ring to the viable tumor. It is suggested that perhaps treatment failure may be determined on sequential CT examinations by comparing the volume and degree of contrast enhancement.

Brain Neoplasms↗

Heavy drinking and the need for power.

Heavy drinking was associated with high power needs but not with low activity inhibition. Heavily drinking women showed significantly lower power needs than heavily drinking men. It is suggested that heavy drinking may be associated with feelings of inadequacy in meeting sex-role expectations.

Adult↗

Total cholesterol, high density lipoprotein-cholesterol and triglycerides after a standardized high-fat meal.

Total cholesterol, high density lipoprotein (HDL)-cholesterol and triglycerides were measured fasting and at 20, 40, 60, 120 and 180 min after a high-fat meal in 22 healthy subjects. Both HDL-cholesterol and total cholesterol fell during the first 20 min after the meal whereas the mean triglyceride level increased during the observation period. In 8 of the subjects the maximum triglyceride level was reached before the end of the observation period and their fasting HDL-cholesterol level was significantly higher than in the rest of the subjects. The higher the fasting HDL-cholesterol concentration, the more rapidly the triglyceride levels returned towards initial values. The study supports the concept that the degradation rate of triglyceride-rich particles is dependent on the HDL-cholesterol level. It also suggests the use of non-fasting triglyceride values in addition to HDL-cholesterol as independent predictors in longitudinal studies for CHD.

Adolescent↗