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Biomedical subjects

P A Barrett

Publications and source records attributed to P A Barrett.

At least 19 recordsLinked to original sources
PubMed1999

Dental technician education and training--a survey.

As the Dental Auxiliaries Review Group report continues in the consultation stage, the dentist needs to keep up-to-date on all aspects of auxiliary career developments. Dental technician education and training has changed radically during the past 25 years as shown by three surveys--the latest carried out during 1998 and reported in this paper. As leader of the dental team, the dentist needs to be aware of these changes in order to make an informed contribution to the debate.

Dental Technicians↗
PubMed1997

Summary oral reflective analysis: a method for interview data analysis in feminist qualitative research.

This article explores an innovative approach to qualitative data analysis called Summary Oral Reflective Analysis (SORA). The method preserves the richness and contextuality of in-depth interview data within a broader feminist philosophical perspective. This multidisciplinary approach was developed in two individual research programs within a cooperative, collaborative arrangement. It represents a creative response to perceived deficiencies in the pragmatics of qualitative data analysis where the maintenance of data contextuality is critical.

Data Interpretation, Statistical↗
PubMed1995

Improving patient quality of life with feedback to physicians about functional status.

OBJECTIVE: To improve functional status among primary care patients. INTERVENTION: 1) Computer-generated feedback to physicians about the patient's functional status, the patient's self-reported "chief complaint," and problem-specific resource and management suggestions; and 2) two brief interactive educational sessions for physicians. DESIGN: Randomized controlled trial. SETTING: University primary care clinic. PARTICIPANTS: All 73 internal medicine house officers and 557 of their new primary care patients. MEASURES: 1) Change in patient functional status from enrollment until six months later, using the Functional Status Questionnaire (FSQ); 2) management plans and additional information about functional status abstracted from the medical record; and 3) physician attitude about whether internists should address functional status problems. RESULTS: Emotional well-being scores improved significantly for the patients of the experimental group physicians compared with those of the control group physicians (p < 0.03). Limitations in social activities indicated as "due to health" decreased among the elderly (> or = 70 years of age) individuals in the experimental group compared with the control group (p < 0.03). The experimental group physicians diagnosed more symptoms of stress or anxiety than did the control group physicians (p < 0.001) and took more actions recommended by the feedback form (p < 0.02). CONCLUSIONS: Computer-generated feedback of functional status screening results accompanied by resource and management suggestions can increase physician diagnoses of impaired emotional well-being, can influence physician management of functional status problems, and can assist physicians in improving emotional well-being and social functioning among their patients.

Activities of Daily Living↗
PubMed1989

Acquired tracheomegaly in adults as a complication of diffuse pulmonary fibrosis.

We studied the chest radiographs of 34 consecutive patients with diffuse pulmonary fibrosis to determine the presence of tracheomegaly and to follow its progression with time. Patients had been identified by a computer search of medical records. We measured the internal transverse diameter of the trachea 2 cm above the top of the aortic arch on erect posteroanterior chest radiographs. Transverse diameters greater than 25 mm in men and 21 mm in women were considered indicative of tracheomegaly. Pulmonary-function tests, available in 30 of the 34 patients, showed restrictive lung disease. The transverse tracheal measurements were compared with the cause of fibrosis, severity of restriction, duration of illness, and other clinical variables. Tracheomegaly was present in 10 (29%) of the patients, including four with fibrosing alveolitis, four with sarcoidosis, and two with chronic progressive histoplasmosis. In seven of these patients, serial radiographs showed that the tracheal dilatation had progressed with time. Nine of 24 patients without tracheomegaly also had progressive increase in transverse tracheal diameter over time. Of the 10 patients with tracheomegaly, pulmonary-function tests were available in eight and showed moderate restrictive lung disease in six and severe restrictive lung disease in two. The duration of illness was 3-6 months in two patients, 10-22 years in five patients, and not recorded in three patients. Chronic cough and repeated respiratory infections were slightly more common in those patients with tracheomegaly than in those without. These data suggest that tracheomegaly develops as a complication of diffuse pulmonary fibrosis in patients who have at least moderate restrictive lung disease and prolonged illness, and it may have some association with chronic cough and repeated respiratory infection.

Adult↗
PubMed1987

Diagnosis of inferior myocardial infarction in the presence of left anterior hemiblock.

Inferior myocardial infarction results in Q waves in the inferior leads of the electrocardiogram (ECG). Left anterior hemiblock results in initial r waves in these leads. Thus the diagnosis of one in the presence of the other is difficult. It has been reported that inferior infarction can be diagnosed in the presence of left anterior hemiblock when there is a q wave or q equivalent in lead II, and that part of the inferior wall must be spared, to result in the initial r waves of left anterior hemiblock in leads III and aVF. We examined these concepts in 18 patients with such an ECG, by means of resting myocardial perfusion (thallium-201) scintigraphy. In 15 there were defects in the inferior left ventricular wall consistent with inferior infarction. In all of these patients there was sparing of part of the inferior wall: in nine, sparing of the posterior part, and in six, sparing of the anterior part. We conclude that in apparently isolated left anterior hemiblock, a q wave or q equivalent in lead II is an important sign, indicating the likelihood of associated inferior infarction.

Diagnosis, Differential↗
PubMed1986

Intrathoracic platelet accumulation in the guinea-pig induced by intravenous administration of arachidonic acid--effect of cyclooxygenase and thromboxane synthetase inhibitors.

Intravenous administration of arachidonic acid to guinea-pigs caused a dose-related, rapid accumulation of 51Cr-labelled platelets in the thorax. Inhibitors of cyclooxygenase inhibited the platelet accumulation, induced by arachidonic acid (30 mg/kg), at doses which did not alter the thoracic blood volume (as measured by 131I-labelled human albumin). Thromboxane synthetase inhibitors had different effects on platelet accumulation depending on the dose. CGS 12970 (3 mg/kg) and N(1-carboxyheptyl) imidazole (100 mg/kg) reduced platelet accumulation. High doses of CGS 12970 and CGS 13080 caused an apparent enhancement of platelet accumulation which was associated with pooling of blood in the thorax, as measured by either 131I-labelled human albumin or 51Cr-labelled erythrocytes. This increase in thoracic blood volume was abolished if the guinea-pigs were also pretreated with diclofenac (1 mg/kg) in addition to the thromboxane synthetase inhibitor. Increases in thoracic blood volume were also obtained following infusions of PGI2 but not PGD2 or PGE2.

Animals↗
PubMed1984

Inhibition by heparin of platelet accumulation in vivo.

In vivo platelet aggregation has been studied using a novel, minimally invasive technique. No aggregatory effects of heparin were observed on normal circulating platelets nor was there enhancement of aggregation of platelets during activation by intravenous injection of ADP, collagen, PAF acether or thrombin. On the contrary, high doses of heparin were found to inhibit platelet accumulation induced by ADP, collagen or PAF-acether. Inhibition of these responses necessitated doses of heparin in excess of those required for anti-coagulant effects. The present experiments do not establish a mechanism for such inhibition. Extension to other species, including man, is needed before attributing clinical relevance to the present observations.

Animals↗
PubMed1983

Shortening of platelet survival by induced hypercholesterolaemia in rabbits and its prolongation by anagrelide.

Induction of atherosclerosis in rabbits by feeding a cholesterol enriched diet reduced the platelet half-life in male rabbits from 37.0 +/- 4.1 hr to 30.1 +/- 3.9 hr (mean +/- S.D. p less than or equal to 0.01). Platelets from these animals exhibited increased sensitivity to arachidonic acid but decreased sensitivity to ADP. No significant change was found in aggregation to collagen or thrombin, or in the production of thomboxane B2 induced by collagen. The reduced platelet survival was dependent upon the recipient animal and not the platelet donor. Platelets from cholesterol-fed animals survived normally in normal animals, whereas platelets from normal animals in cholesterol-fed animals had a reduced platelet survival even compared to platelets from cholesterol-fed animals. This might suggest that some functional change had occurred in the cholesterol platelet in response to its altered environment. Anagrelide (1 mg/kg/day) normalised shortened platelet survival in both male and female rabbits fed the high cholesterol diet.

Animals↗
PubMed1982

The efficacy of a novel compound, (e)-1-(4'-bromo-4-biphenylyl)-1-(4-chlorophenyl)-3-dimethylaminoprop-1-ene against Trypanosoma cruzi in mice.

The biological properties of a novel compound 353C with high activity against Trypanosoma cruzi, are described. The compound was about 10 times and 20 times more effective than either benznidazole or nifurtimox respectively, in producing radical cure in mice. 353C has a long half-life and showed anti-trypanosomal properties when given to mice at weekly intervals.

Animals↗
PubMed1982

A second zone of compensation during atrial premature stimulation: evidence for decremental conduction in the sinoatrial junction.

125 consecutive patients with premature atrial stimulation were studied. Three demonstrated sinus node return cycles that were fully compensatory following premature atrial stimuli delivered early in diastole. This second zone of compensation was unaccompanied by significant alterations in the post-return cycle lengths or in P-wave morphology of the return cycle. To account for the occurrence of a complete compensatory pause following very early premature atrial depolarizations, we consider the possibility that retrograde conduction of the early atrial premature depolarization (APD) in the sinoatrial junction was delayed for a sufficient length of time to allow the sinus node to depolarize spontaneously on schedule. Collision between the APD and sinus beat would then occur despite the marked prematurity of the APD. Thus, the early APD had encountered the relative refractory period of the sinoatrial junction, suggesting that decremental conduction takes place within the sinoatrial region in man. These findings imply that there is the potential for reentry in the region of the human sinoatrial junction.

Aged↗
PubMed1981

Amrinone--a new inotropic agent in chronic resistant congestive cardiac failure.

A patient with severe cardiac failure due to idiopathic congestive cardiomyopathy resistant to conventional therapy, responded to amrinone, a new non-glycosidic non-catecholamine positive inotropic agent. Amrinone produced significant haemodynamic improvement during both intravenous and oral administration. Thrombocytopaenia, however, was induced, necessitating cessation of the drug. Amrinone is a promising, orally effective inotropic agent for patients with refractory congestive cardiac failure, but is limited to its tendency to cause thrombocytopaenia.

Administration, Oral↗
PubMed1981

Diagnosis of old anterior myocardial infarction in emphysema with poor R wave progression in anterior chest leads.

The electrocardiograms of patients with emphysema may suggest associated old anterior myocardial infarction. Sixteen patients with the physiological characteristics of emphysema were studied, who also showed poor R wave progression in the anterior chest leads, so that RV3 was less than or equal to 4 mm. A thallium-201 cardiac scan consistent with previous anterior (septal) myocardial infarction was present in seven patients. In these patients there was no significant increase in RV3 amplitude when recorded one interspace below the conventional site. In the nine patients with a thallium-201 cardiac scan negative for old anterior myocardial infarction, RV3 amplitude increased from 2.2 +/- 0.4 mm to 6.4 +/- 1.2 mm. Patients with or without associated old anterior myocardial infarction could be better diagnosed by consideration of RV3 amplitude as recorded from one interspace lower, as compared with conventional electrode placement. All five patients with RV3 (lower interspace) less than 2 mm had associated anterior infarction, and all seven patients with RV3 (lower interspace) greater than 3 mm did not. This simple manoeuvre is recommended in patients with emphysema and an electrocardiogram suggestive of old anterior myocardial infarction.

Adult↗
PubMed1981

Electrophysiological factors of left bundle-branch block.

Left bundle-branch block is rarely an isolated disorder of conduction, additional disorders being found in 29 of 30 patients studied by intracardiac stimulation techniques. These included disorders of sinus node function (prolonged maximum sinus node recovery time (corrected) in 23%, prolonged sinuatrial conduction time in three of eight patients), atrioventricular node function (prolonged AH interval in 33%, prolonged effective and functional refractory periods in 37% and 74%, respectively), "His bundle to right bundle branch" conduction (prolonged HV interval in 53%), and ventriculoatrial conduction (absent in 62%). It is postulated that at least half of the cases of left bundle-branch block were incomplete, even though the duration of the QRS complex exceeded 120 ms, because of (further) leftward deviation of the mean frontal QRS axis with sufficiently premature atrial extrastimuli. Block may be complete or incomplete in left bundle-branch block with left axis deviation of -30 degrees or more on the standard electrocardiogram.

Adult↗
PubMed1980

The electrophysiologic effects of intravenous lidocaine in the Wolff-Parkinson-White syndrome.

Twelve patients with the Wolff-Parkinson-White syndrome underwent electrophysiologic study, before and after the bolus intravenous administration of lidocaine, 1 mg./kg. There was no significant increase in the effective refractory period of the anterograde AV node pathway, the anterograde or retrograde accessory pathway, or the atrial or ventricular muscle; intravenous bolus administration of lidocaine is unlikely to terminate the re-entry tachycardias, or decrease the rate of the ventricular response in atrial fibrillation, in the WPW syndrome. There was no significant increase in the anterograde or retrograde AV conduction times; bolus administration of lidocaine is unlikely to decrease the rates of the re-entry tachycardias. In addition, lidocaine failed to alter significantly features related to tachycardia initiation. Except in isolated, unpredictable cases, intravenous bolus administration of lidocaine is not likely to be of benefit in the supraventricular tachyarrhythmias of the WPW syndrome.

Adolescent↗