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Biomedical subjects

A Hart

Publications and source records attributed to A Hart.

At least 109 records · Page 6Linked to original sources
PubMed1981

Improved diagnosis of neural tube defects: measurement of concanavalin A-reactive variants of AFP in amniotic fluid.

The proportion of alphafetoprotein (AFP) not reacting with Concanavalin A(Con A) was determined by crossed line affinity immunoelectrophoresis (CLAIE) in amniotic fluid obtained from 16 pregnancies with open neural tube defects and other fetal abnormalities, and 25 pregnancies with normal outcome. The percentage of Con A non-reactive AFP was significantly lower in the presence of open neural tube defects (less than 3.9%, n = 13) compared with that in normal pregnancy (range 6.4-25.2%, n = 25). In this retrospective analysis, 2 pregnancies affected by open neural tube defect escaped diagnosis on the basis of an ambiguous total AFP estimation (+2SD less than x less than +5SD) in the amniotic fluid. These observations suggest that the elimination of false diagnose based on total AFP levels may be possible, if supplementary analysis by CLAIE is performed.

Amniotic Fluid↗
PubMed1981

Clinical significance of intraoperative flow measurement during bovine heterograft AV fistulae formation.

Between July 1977 and July 1979, 85 new upper arm bovine grafts were constructed and were followed up to June 1980. We divided the patients into 3 groups on the basis of the rate of blood flow through the graft. In group I, whose rate was less than 500 ml/min, the graft had a short life span. The group whose blood flow rate was higher than 1000 ml/min had a high incidence of complications, such as "steal" syndromes and congestive heart failure. Best results were achieved with a blood flow rate between 500 ml/min and 1000 ml/min.

Arm↗
PubMed1980

Training: five stars for the White Hart.

It is important that NHS staff should be aware of the service offered by the training and studies centre at Harrogate, writes Alex Hart, the centre's principal. Housed in the White Hart, a Georgian style building which was originally a hotel, it has a small staff and a distinctive method of operation.

Education, Continuing↗
PubMed1977

Catecholamine-induced muscle weakness.

Infusions of epinephrine or levarterenol bitartrate into a rabbit nerve-muscle preparation decreased the force of the evoked twitch of anterior tibial and gastrocnemius-soleus muscles. The adverse effect of the catecholamines was not directly on skeletal muscle. The alpha-receptor blocking drug phenoxybenzamine hydrochloride prevented the adverse effect of the catecholamines if it was given prior to catecholamine infusions and unmasked a weak augmentation of twitch tension. Taken with the finding of abnormal accumulation of catecholamine in human dystrophic muscles, the production of an experimental myopathy resembling human dystrophy by the monoamine oxidase inhibitor pargyline hydrochloride, and the finding of excessive levels of catecholamines in the tissues and urine of dystrophic animals, these experiments support the hypothesis that catecholamines could play a pathogenetic role in some dystrophic diseases of muscle.

Action Potentials↗
PubMed1977

Functional status of patients with large ventricular septal defect and pulmonary vascular disease 6 to 16 years after surgical closure of their defect in childhood.

We have reviewed 27 patients now 6 to 16 years after closure of a ventricular septal defect at 3 to 12 years of age associated with pulmonary hypertension with a view to assessing their quality of life, respiratory function, and exercise performance. All the patients led normal unrestricted lives. Their subjective lack of symptoms was, in general, confirmed by the results obtained from assessment of lung function tests and two-stage exercise testing in 19 volunteers. Abnormal ventilation in relation to work load was noted in 5 patients and a slightly low exercise cardiac output in 6. Although the patients led normal lives and had a satisfactory response to exercise, measurement of pulmonary artery pressure showed striking pulmonary hypertension on effort. Despite the satisfactory progress of these patients their more long-term future must be one of conjecture and their residual pulmonary hypertension, indicative of residual pulmonary obstruction, must lend weight to arguments for earlier closure of ventricular septal defect before 1 to 2 years of age when changes in the pulmonary vascular bed may be reversed after closure of the defect.

Adolescent↗
PubMed1977

Stroke: incidence and risk factors.

The incidence of stroke was estimated prospectively in a total population of 2,502 persons over age 65 who resided in homes for the aged. The incidence in persons born in Asian and African countries was close to that in persons born in European countries. No sex differential was found in either ethnic group, and there was no significant increase in the incidence of stroke with advancing age in either sex. In the European population, prior heart disease was the strongest risk-increasing factor, ranking ahead of hypertension. Diabetes mellitus was not associated with a higher risk of stroke among the women; the findings for the men were inconclusive. In the Afro-Asian population, the risk of stroke was related to heart disease and diabetes mellitus but was not associated with blood pressure. Total serum cholesterol or relative weight was not associated with stroke in either group. The early establishment of programs for the control of hypertension and stroke appears most desirable.

Age Factors↗
PubMed1976

The initial manifestations of acute myocardinal infarction.

A review of 132 consecutive patients 65 years of age and older who had a myocardial infarction showed that two-thirds of them experienced pain at onset. Pain was the only symptom leading to bedside diagnosis in one-fourth of the patients. Pain at onset combined with sudden or increased dyspnea was present in one-fifth of the patients and pain associated with other symptoms in one-sixth. Dyspnea unaccompanied by pain heralded onset of infarction in one-fifth of the patients, and in almost 7 percent, onset was marked only by other symptoms. Cerebral symptoms dominated onset in one-tenth of the patients. Preexisting coronary heart disease, hypertension, or diabetes was not predictive of painless infarction. To avoid pitfalls and facilitate bedside diagnosis of infarction, physicians should be aware of the different clinical presentations of painless infarction in the aged, which occurred in over one-third of the patients in this cohort. They also should suspect the possibility of myocardial infarction in any patient in whom symptoms are not clear, even when they are mild and unobtrusive. Questioning of the elderly patient, his family, or others around him as early as possible after the onset of an acute attack is likely to elicit a history of pain, which may lead to the correct diagnosis.

Acute Disease↗
PubMed1975

The degradation of paracetamol (4-hydroxyacetanilide) and other substituted acetanilides by a Penicillium species.

A mould which was isolated from a solution of paracetamol was identified as a Penicillium species and was found to possess the ability to utilise a series of substituted acetanilides, including paracetamol (4-hydroxyacetanilide), phenacetin (4-ethoxyacetanilide) and metacetamol (3-hydroxyacetanilide) as sole carbon sources for growth. Studies with washed-cell suspensions indicated that growth of the Penicillium isolate in the presence of paracetamol induced the respective enzyme systems for the degradation of this compound. Manometric studies measuring oxygen uptake rates, indicated that the mould was capable of degrading paracetamol to acetate and 4-aminophenol. Acetate was further metabolised whilst 4-aminophenol accumulated in the growth medium and was subsequently i-entified by UV spectroscopy and thin-layer chromatography. Similar experiments with phenacetin indicated metabolism by the mould to acetate and 4-ethoxyaniline which was isolated and identified by subsequent analysis of the growth medium. However, unlike 4-aminophenol and 4-ethoxyaniline, the degradation product (3-aminophenol) from metacetamol metabolism was further degraded by the mould.

Acetaminophen↗
PubMed1975

Bioavailability and dissolution of different formulations of oxytetracycline preparations.

1 The concentration of oxytetracycline in plasma was studied by microbiological assay after oral administration of five different preparations of the antibiotic. None of these preparations had been studied previously. 2 There was a statistically significant correlation between the time required for 50% dissolution at pH 2 and biological availability, as assessed by the peak plasma level or the area under the plasma concentration-time curve. 3 The mean bioavailability of oxytetracycline was greatest with preparations of the hydrochloride, and with film-coated tablets of the dihydrate. In contrast, sugar-coated tablets of oxytetracycline dihydrate were associated with poorer dissolution characteristics and reduced biological availability.

Biological Availability↗