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Biomedical subjects

D Hughes

Publications and source records attributed to D Hughes.

At least 307 records · Page 17Linked to original sources
PubMed1982

Secondary myogenesis of normal muscle produces abnormal myotubes.

The extensor digitorum longus muscles of 2-, 4-, and 12-week-old 129-ReJ mice were subjected to homotopic, whole-muscle transplantation. Subsequent to myofiber necrosis and phagocytosis, a new population of myotubes was produced. The three-dimensional cytoarchitecture of these newly formed myotubes was determined in spaced, serial, ultrathin sections. Myotubes, which for long distances along their length appeared to be separate and discrete, were found to branch and recombine, forming a complex syncytium.

Aging↗
PubMed1982

A comparison of two procedures to elicit verbal auxiliary and copula in normal kindergarten children.

Fourteen normal kindergarten children, all of whom spontaneously used verbal auxiliary and copular forms of BE (VACs) were studied. Two cloze procedures were designed to elicit all three forms of present tense VACs in uncontractible sentence positions. The syntactic elicitation (SE) procedure required the children to observe a syntactic constraint within a descriptive response; the emphatic elicitation (EE) procedure required observation of a stress constraint within a role-playing response. Personal pronouns were used as sentence subjects in both procedures. Results indicated that both procedures were effective in eliciting VACs approximately 75% of the time. The SE procedure was more effective than the EE procedure overall. The procedures did not differ in their ability to elicit auxiliary and copular forms. The effects of subject pronoun person and singular vs. plural verb form are discussed. The procedures have implications for supplementing spontaneous language samples in assessing expressive language.

Child↗
PubMed1982

The immediate effect of sodium cromoglycate on the airway.

The authors compared the bronchodilator effect of nebulized solutions of sodium cromoglycate (SCG), salbutamol, and saline (placebo) in 10 asthmatic children, measuring peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced expiratory flow from 25% to 75% of the forced vital capacity (FEF25%-75%) before and every five minutes to a maximum of 20 minutes after each aerosol. SCG produced significant bronchodilation compared with saline as measured by PEF. This effect was not seen with FEV1 or FEF25%-75%. Salbutamol had a more immediate effect and produced a greater degree of bronchodilation than SCG. When an immediate bronchodilator effect is required SCG is not recommended.

Airway Obstruction↗
PubMed1981

Yersinia enterocolitica in raw goat's milk.

Biochemical and serological data are presented for 35 isolates of Yersinia enterocolitica from raw goat's milk produced in New South Wales, Australia. Strains resembled biotype I or 2, but the majority (25 of 35) fermented rhamnose and some showed other atypical reactions.

Animals↗
PubMed1981

Right ventricular performance in essential hypertension after beta-blockade.

Recent studies indicate that right ventricular performance is impaired even in uncomplicated systemic hypertension. Because of widespread use of beta-blockade in essentially hypertension, it is possible that such treatment often further depresses right ventricular contractility. To test this premise, and to evaluate the changes induced by different beta-adrenoceptor blocking agents on the contractility of right ventricular myocardium, 20 patients with essential hypertension were divided into two groups on a double-blind randomised basis, and maintained on oral oxprenolol or propranolol for five weeks. Cardiac catheterisation and right ventricular cineangiography were performed at the beginning and again at the end of the five week period. Right ventricular end-diastolic volume index did not change significantly in either group. In contrast, right ventricular end-systolic volume index increased, and right ventricular ejection fraction significantly decreased after chronic beta-blockade. Cardiac index decreased in both groups, but these changes were not statistically significant. When the intergroup differences were compared for all measured indices none of the changes between the two groups was statistically significant. Despite its intrinsic sympathomimetic activity, oxprenolol therefore impairs right ventricular performance to an extent nearly equal to that of propranolol. Moreover, right ventricular contractility is clearly diminished after the institution of beta-blockade in hypertensive patients--an effect that has until now been thought to be limited to the left side of the heart. Great caution must therefore be exercised when beta-blockade is initiated in patients with severely abnormal right ventricular function, because frank right ventricular decompensation may result.

Clinical Trials as Topic↗
PubMed1980

Medical student selection: a tentative attempt to establish a code of practice.

Each year medical schools in the United Kingdom select about 3800 entrants from about 12 000 applicants. The problem of selection is thus substantial, but the objectives, policies, and practices of different medical schools differ sharply and details of the procedures used are rarely made clear. There is no reliable or up-to-date information available for schools, careers of advisers, and prospective candidates to keep abreast of these practices and policies and of changes made to them. A code of practice for medical student selection might be helpful and would not only facilitate discussion about the appropriateness and fairness of the widely differing practices but make it easier to evaluate the procedures used. Such a code should list the academic and personal requirements for the school, state any quotas for types of entrants, and describe the selection procedures.

Education, Medical, Undergraduate↗
PubMed1980

Use of nondifferentiable optimization in a health care problem.

Those who study health care systems (HSC) seek to model the features of health care systems of societies that are common to different countries, so as to assist those who plan health services. The mathematicians interested in nondifferentiable optimization (NDO) seek to extend the classical optimization techniques to functions that have "non-smooth" regions where no unique gradient can be defined. This article reports how a health resource allocation model was solved by minimizing a function with points of nondifferentiability. It describes how an example of the model arose in the joint strategic planning of health and personal social services in a county in England with a population of about one million. It also formulates the model as a problem of NDO. Ways to obtain numerical solutions are reviewed, and the solution of the example by NDO is compared to another method based on linear approximation.

Aged↗
PubMed1980

Antihypertensive and hemodynamic effects of oxprenolol versus propranolol.

Oxprenolol is an experimental beta adrenergic blocker with intrinsic sympathomimetic activity. To compare the effects of long-term administration of oxprenolol on hypertension and hemodynamics with the effects of propranolol, 20 patients with essential hypertension were divided in a double-blind random manner into two 10-patient groups and given placebo for 2 wk, followed by equipotent doses of oxprenolol or propranolol for 5 wk and by placebo for another 2 wk. Right heart cardiac catheterization was performed at the beginning and at the end of the 5-wk beta blockade. Heart rates and blood pressures fell markedly with both agents, although standing heart rate was lowered more by propranolol than by oxprenolol. Plasma renin activity was much lower after beta blockade with either drug. There was no correlation between decreases in blood pressure and renin activity. Although during the stress of repeat cardiac catheterization heart rates remained significantly lower than control, the intra-arterial pressures were not altered significantly by oxprenolol or propranolol, nor was there significant change in pulmonary pressure, vascular resistance, or cardiac output. Thus oxprenolol closely parallels the effects of propranolol in essential hypertension. The negative chronotropic action of both drugs is more marked than their antihypertensive activity.

Adult↗
PubMed1980

Linoleic acid therapy in severe experimental allergic encephalomyelitis in the guinea-pig: suppression by continuous treatment.

The effect of oral linoleic acid (LA) treatment on experimental allergic encephalomyelitis (EAE) in guinea-pigs in three trials of differing disease intensity has been investigated. The efficacy of LA treatment was linked to the severity of the disease being suppressed. The trial with the greatest disease severity showed no beneficial effect. The other two trials with less severe disease showed a marked therapeutic response to LA, but only when treatment was started before immunization and given continuously. This was apparent in both clinical and histopathological responses. These results support an immunoregulatory mechanism for LA treatment in EAE and by analogy in multiple sclerosis.

Animals↗
PubMed1979

Prognostic value of a persistently positive technetium-99m stannous pyrophosphate myocardial scintigram after myocardial infarction.

Technetium-99m stannous pyrophosphate myocardial scintigrams were obtained in 138 clinically stable patients 32.7 +/- 47.3 weeks (range 6 to 260) after acute myocardial infarction. Of the 138 patients, 74 (54 percent) had a persistently positive scintigram. Patients with such a scintigram were more likely to have severe angina pectoris, compensated congestive heart failure, anterior location of acute myocardial infarction, Q waves and S-T segment elevation in the electrocardiograms, cardiomegaly, left ventricular dyssynergy (dyskinesia or global dyssynergy), and an ejection fraction of less than 50 percent. During a follow-up period of 11.6 +/- 6.9 months after scintigraphy, 42 percent of the patients with a persistently positive scintigram had either a cardiac death, a nonfatal myocardial infarction, unstable angina pectoris or decompensated congestive heart failure compared with 13 percent of the patients with a negative scintigram (P less than 0.001). Of the 14 patients with cardiac death, 13 (93 percent) had a persistently positive scintigram. A persistently positive scintigram not only was the best single predictor of cardiac death and combined end points, but also added significantly to the predictive ability of the other clinical variables, including age, location of acute myocardial infarct, clinical status, electrocardiographic findings, and chest X-ray findings. It is concluded that technetium-99m stannous pyrophosphate myocardial scintigraphy has prognostic value in patients after acute myocardial infarction.

Adult↗
PubMed1979

Multiple sclerosis-associated agent. Failure of MS brain and serum to depress the polymorph count in normal mice and mice inoculated with cells containing C/type particles.

The groups that originally reported and confirmed the demonstration of a multiple sclerosis associated agent (MSAA) are now, along with others, unable to reproduce this effect. In view of this confusion and the potential importance of this work for multiple sclerosis (MS) we have done a strict double-blind trial using larger groups of mice (10) and counting more cells (900) than in previous reports to offset the high variability of mouse polymorphonuclear neutrophil (PMN) counts. Sera from 5 active MS patients and 4 normal subjects were tested in mice, half of which had previously been injected with PAM line cells (containing C-type particles and subject to reduced cell yield when cultured with MS brain extract). No significant PMN depression was found in either MS or normals on any basis of comparison. However, a significant depression was seen following PAM cell injection irrespective of serum origin. Higher counting accuracy did not reduce PMN variability. A single MS brain specimen was also without effect. consequently we have been unable to confirm the existence of an MSAA as defined by PMN depression in mice.

Animals↗