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Biomedical subjects

D Watson

Publications and source records attributed to D Watson.

At least 181 records · Page 10Linked to original sources
PubMed1988

Coronary awareness--evaluation of a week's campaign.

An intensive Healthy Heart week was organised in Halstead, Essex. Financed by a district health authority grant, the week involved intensive preparation by a multi-disciplinary working party, and a number of events, as well as a mass mailing. Although evaluation found some positive results, the overall conclusion was that the results did not justify the effort. However, support from the local community was felt to be valuable, and likely to be the most important lasting effect.

Attitude to Health↗
PubMed1988

Posttest probability calculation by weights. A simple form of Bayes' theorem.

This article reintroduces a different form of Bayes' theorem that allows calculation of posttest probabilities by adding quantities known as "weights." A weight combines information found in both a test's sensitivity and specificity. A single value can describe how a given test result changes the posttest probability of disease. The use of weights and this form of Bayes' theorem should allow more widespread understanding and use of probability theory in clinical practice.

Bayes Theorem↗
PubMed1987

Metabolism of the mutagen MeIQx in vivo: metabolite screening by liquid chromatography-thermospray mass spectrometry.

2-Amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx) is a potent mutagen found in cooked food. MeIQx and its isotopically labelled (13C, 15N2 and 14C) analogues were synthesised and used for metabolic studies in vivo. An equimolar mixture of MeIQx and its 13C, 15N2 stable isotope labelled analogue (containing tracer amounts of 14C-MeIQx) was given intraperitoneally to mice. Some 67% of the radioactivity was eliminated in urine and faeces within 24h. Four radiolabelled species were observed when urine was analysed by HPLC, corresponding to unchanged MeIQx and three more polar metabolites. Urine was analysed directly by HPLC-thermospray mass spectrometry. Four signals were observed containing the characteristic 1:1 isotopic doublet, corresponding to unchanged MeIQx, an MeIQx glucuronide, and two uncharacterized metabolites.

Animals↗
PubMed1987

Colchicine myopathy and neuropathy.

Although colchicine has been used for centuries, its neuromuscular toxicity in humans is largely unrecognized. In this report we describe a characteristic syndrome of myopathy and neuropathy and present 12 new cases of the condition. Colchicine myopathy may occur in patients with gout who take customary doses of the drug but who have elevated plasma drug levels because of altered renal function. It usually presents with proximal weakness and always presents with elevation of serum creatine kinase; both features remit within three to four weeks after the drug is discontinued. The accompanying axonal polyneuropathy is mild and resolves slowly. Electromyography of proximal muscles shows a myopathy that is marked by abnormal spontaneous activity. Because of these features, colchicine myoneuropathy is usually misdiagnosed initially, either as probable polymyositis or as uremic neuropathy. The myopathy is vacuolar, marked by accumulation of lysosomes and autophagic vacuoles unrelated to necrosis or to the mild denervation in distal muscles. The morphologic changes in muscle suggest that the pathogenesis involves disruption of a microtubule-dependent cytoskeletal network that interacts with lysosomes. Correct diagnosis may save patients with this disorder from inappropriate therapy.

Action Potentials↗
PubMed1987

Biomedical applications of thermospray liquid chromatography-mass spectrometry.

Thermospray liquid chromatography-mass spectrometry has been applied in the solution of a number of problems of biological and biomedical interest. These include the analysis of phenazines from the Gram negative bacterium Pseudomonas aeruginosa, steroids released by rat adrenals and eicosanoids generated by human inflammatory cells. The application of the technique to leukotrienes in blood is discussed. Isotopic labelling prior to analysis, to facilitate identification and structure elucidation is outlined with reference to the steroids.

Adrenal Cortex Hormones↗
PubMed1987

Review of intermittent dobutamine infusions for congestive cardiomyopathy.

Dobutamine is a potent inotropic agent traditionally used for treatment of acute cardiac decompensation of congestive heart failure (CHF). It acts primarily by increasing myocardial contractility and cardiac output. It has a rapid onset of action, a half-life of 2 minutes, and a duration of action of 10 minutes. Recently, the therapeutic effect of dobutamine was noted to be prolonged beyond the discontinuation of an infusion, persisting for 4-10 weeks after infusion of 48-72 hours. Because of this prolonged effect, dobutamine infusions were evaluated in outpatients with intractable CHF and were effective in improving their functional status. No effect on survival rates may be expected, but this form of therapy may improve the patient's lifestyle. Although several factors may limit the application of dobutamine infusion to outpatients, it offers an effective alternative to traditional therapy for select patients.

Dobutamine↗
PubMed1987

Diagnosis and treatment of intrapericardial teratoma.

Intrapericardial teratoma is a rare mediastinal tumor that originates from aberrant clusters of multipotential cells from three germinal layers. Previous reports have used the combination of cardiac angiography, CT scan, and echocardiogram to establish the diagnosis prior to surgery. We report a case of intrapericardial teratoma diagnosed noninvasively and removed surgically within the first three days of life. Furthermore, we compare the diagnostic accuracy of echocardiography and computerized tomography (CT), and discuss the superiority of noninvasive evaluation in the management of these critically ill infants.

Echocardiography↗
PubMed1987

Pyocyanin and 1-hydroxyphenazine produced by Pseudomonas aeruginosa inhibit the beating of human respiratory cilia in vitro.

Pseudomonas aeruginosa culture filtrates varied in their ability to slow human ciliary beat frequency (7-71%). This activity did not correlate with known virulence factors. However, a close correlation (r = 0.97) existed between ciliary slowing and pigment content. In a prolonged culture, the increase in activity correlated (r = 0.94) with pigment accumulation. Gel filtration of lyophilized filtrate yielded a single peak of activity corresponding to the pigment fraction. Pyocyanin extracted from an active strain, and 1-hydroxyphenazine were purified by high performance liquid chromatography, and characterized by ultraviolet absorbance spectra and mass spectrometry. Both slowed cilia in a dose-dependent manner, and were synthesized and shown to be indistinguishable from the biological compounds. Pyocyanin caused gradual onset of slowing and ultimate widespread ciliostasis with epithelial disruption. 1-hydroxyphenazine caused rapid onset of ciliary slowing associated with dyskinesia and ciliostasis. Pyocyanin assayed within filtrates accounted for a significant proportion of the bioactivity present.

Alginates↗
PubMed1987

Erythrocyte fatty acid profiles in patients with bronchogenic carcinoma.

The use of the erythrocyte stearic:oleic acid ratio in the diagnosis and prognosis of bronchogenic carcinoma has been assessed. Although there was a significant difference (P less than 0.02) in the erythrocyte stearic:oleic acid ratio between bronchogenic carcinoma patients and healthy adults, the large overlap observed in the two groups rendered the test unsuitable for the diagnosis of malignancy. Furthermore, there was no consistent rise in this ratio after surgical resection, indicating the test to be of little prognostic use. A new explanation for the lower stearic:oleic acid ratios in certain patients has been postulated.

Adult↗
PubMed1987

The integration of respiratory therapy into nursing: reorganization for improved productivity.

This article outlines a program, implemented by a 133-bed acute care facility, designed to provide more productive patient care delivery while maintaining the level of service delivered. This program required downsizing the respiratory therapy department, integrating a portion of its function into the nursing department, and reducing the annual salary budget by approximately $270,000 or 2 percent of total hospital salaries. The article describes the process and strategies that were used to implement this method of providing respiratory care to hospital patients.

Centralized Hospital Services↗
PubMed1986

Purification and structural analysis of pyocyanin and 1-hydroxyphenazine.

Pyocyanin and related members of the phenazine family are produced by Pseudomonas aeruginosa and have been associated with events of pathophysiological importance. Pyocyanin and its base hydrolysis product 1-hydroxyphenazine were purified to homogeneity by reverse-phase high-pressure liquid chromatography. Their mass spectrometric behaviour was examined with a view to evaluating the use of high-resolution chromatography/mass spectrometry in studying phenazine-mediated effects in man. The molecular mass of naturally derived pyocyanin was determined as 210 Da by thermospray liquid chromatography/mass spectrometry and confirmed by desorption electron-impact mass spectrometry. Mass spectrometric data could not be obtained by fast-atom bombardment or desorption chemical ionisation, techniques commonly used to determine molecular mass of polar or thermally labile species. The thermal lability of underivatised pyocyanin precluded analysis by gas chromatography/mass spectrometry. In contrast to pyocyanin, mass spectrometric data were readily obtained for 1-hydroxyphenazine, using direct probe analysis as well as with gas and liquid chromatography inlet systems.

Chromatography, Gas↗