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Biomedical subjects

R Thompson

Publications and source records attributed to R Thompson.

At least 271 records · Page 15Linked to original sources
PubMed1985

Haemodynamic adaptation to exercise in asymptomatic patients with severe aortic regurgitation.

Thirty-six patients with severe aortic regurgitation and 10 normal subjects underwent radionuclide angiography to examine the cardiovascular adaptations to exercise. Patients were sub-divided into four groups based on the directional change of ejection fraction with exercise. Group A (15 patients) showed normal ejection fraction at rest and peak exercise (0.65 +/- 0.05 and 0.73 +/- 0.06 respectively). Group D (six patients) showed significant abnormalities in left ventricular function at rest with further deterioration during exercise (0.44 +/- 0.09 to 0.35 +/- 0.07 respectively). In patients with good left ventricular function left ventricular end-diastolic and end-systolic volume decreased progressively with exercise and at peak exercise end-systolic volume was within normal limits. In patients with poor left ventricular function both end-diastoic and end-systolic volume progressively increased with exercise. Both net and total stroke volume were significantly higher at rest in patients with normal left ventricular function but net stroke volume increased with exercise only in those with good myocardial function and was quantitatively similar to that seen in normal subjects. The severity of aortic regurgitation as judged by regurgitant fraction was reduced during exercise in all except four patients, by an average of 22% in all groups. The major factor determining increasing cardiac output with exercise was found to be the status of myocardial function. Although reduction in the severity of aortic regurgitation may favourably influence distribution of stroke volume in those with normal myocardial function, it failed to contribute significantly to increasing cardiac output in those with poor left ventricular function.

Adolescent↗
PubMed1985

Creative nursing: processive care and more?

The authors describe a crisis point which led them from considering a reorientation of the present BSc (Nursing) curriculum at the University of Cape Town, South Africa to undertaking a radical revision of the degree programme. While examining final year students they realized that the nurses' excellent personal qualities apparent in everyday relationships, were not being used in their professional practice on hospital wards. It is suggested that this is due partly to an educational programme which neglected what the students already had (common sense and logic) and what they already knew from life experience and from instinct and intuition. It is also supposed that when hospital wards are their first clinical learning areas, nurses divorce patients and disease from the 'real' world, from the essentials of daily living and from the components of an individualized lifestyle. A staged process of learning experience, to include looking after healthy, elderly and disabled individuals in homes and institutions--with minimal nurse supervision--before exposure to hospital life, is advocated. In its present form the nursing process is seen as limiting the creativity of nursing practice and the authors suggest that further development of this approach is necessary if nursing science is to be interpreted as an art. Finally, the authors outline an experimental curriculum which takes cognisance of their experiences and syllogistic reasoning, together with a brief description of the first few months of its implementation at the University of Cape Town.

Creativity↗
PubMed1985

Infants' affective responses in the strange situation: effects of prematurity and of quality of attachment.

20 full-term and 20 preterm infants and their mothers were videotaped in the Strange Situation, and the security of their attachment relationships was later determined. Each episode was subsequently divided into consecutive 15-sec intervals, during each of which ratings of facial expressions were performed. From these ratings several summary dimensions of affect were derived (e.g., affective peak and range during all episodes, latency and rise time for onset of distress during separation episodes, and recovery time during reunions). Term and preterm infants did not differ from one another in either the security of attachment or their affective expression and regulation. When groups were combined, patterns of affective expression were significantly different for infants classified as insecure-avoidant, insecure-ambivalent, and securely attached, as well as for group B1 + B2 infants compared to group B3 + B4 babies. The findings indicated that attachment-related affect may reflect an affect continuum that underlies certain mother- and stranger-directed behaviors in the Strange Situation, but that not all aspects of reunion behavior can be predicted by prior separation reactions.

Affect↗
PubMed1985

Magnetic resonance imaging of the interatrial septum and atrial septal defects.

Magnetic resonance images were obtained in six patients with known or suspected interatrial septal defects (ASD) and 33 subjects without congenital heart disease. Image planes were oriented to the long and short axes of the left ventricle and septum and provided reproducible display of pertinent anatomic landmarks. Of the images in 33 control subjects, three (9%) were falsely positive showing apparent ASD. ASDs were correctly identified and localized in all six patients (five secundum, one primum). Long-axis views provided excellent display of the location and diameter of defects. All were confirmed at cardiac catheterization and four at surgery with good agreement in measurement of defect size and location. All showed signs of right-sided volume overload. Five had previous echocardiography, which showed definite or suspected ASD in four.

Adult↗
PubMed1985

Magnetic resonance imaging of the heart using image planes oriented to cardiac axes: experience with 100 cases.

Electrocardiographically gated magnetic resonance images were acquired in 100 patients with a variety of cardiac diagnoses in planes oriented to intrinsic axes of the heart and aorta. The technique used combines patient positioning and alteration of magnetic gradient angle. Images in these planes appear to have advantages over conventional orthogonal images, both for display of cardiovascular anatomy and for evaluation of cardiac size and function.

Adolescent↗
PubMed1985

Rotavirus electrophoretypes in infantile gastro-enteritis. An epidemiological study.

From January first 1978 to September 30, 1981, 93 fecal samples from children hospitalized with a rotavirus gastro-enteritis were tested after RNA extraction and polyacrylamide gel electrophoresis. 14 electrophoretypes (TI--T14) were identified by this technique. They were studied in relation with epidemiological as well as clinical symptoms. No electrophoretype correlated well with age or living area. The electrophoretype T3 was found only in male infants and the electrophoretype T7 was 3 times more frequent in boys than in girls. The electrophoretype T4 was prevailing during the winter 1980-1981 and the electrophoretype T5 prevailed during the summer 1981. 19 infants were probably contaminated during their stay in the hospital, 9 of them with the electrophoretype T4 prevailing at that time. The prevalence of associated otitis and rash was significantly higher with the electrophoretype T3. The polyacrylamide gel electrophoresis technique appears to be a simple, and reliable epidemiological tool to evaluate rotavirus infection in communities.

Child, Preschool↗
PubMed1985

Angiographic contrast agent-induced acute hemolysis in a patient with hemoglobin SC disease.

Radiographic contrast media used for angiographic procedures are hyperosmolar and induce sickling in vitro of erythrocytes from patients with sickle cell disorders. We treated a 51-year-old black woman with hemoglobin SC disease, but without a history of painful crises, who developed severe intravascular hemolysis and pulmonary infiltrates following administration of a contrast agent for coronary angiography and ventriculography. This case emphasizes the potential for severe complications following administration of the currently available contrast agents to patients with sickle cell disease. We suggest that newer contrast agents with lower osmolality than the commonly used ones need to be carefully evaluated for radiologic studies in patients with sickle cell disease.

Anemia, Hemolytic↗
PubMed1985

The computed tomographic spectrum of cerebral cysticercosis.

A review of the disease cerebral cysticercosis is presented. The pathogenesis, symptomatology, diagnosis, and treatment of this disease is discussed with an emphasis on the role of computed tomography in the diagnosis of cerebral cysticercosis.

Adolescent↗
PubMed1985

Cardiac magnetic resonance imaging: the Massachusetts General Hospital experience.

The combination of gated cardiac imaging with the magnetic resonance parameters of flow void and tissue characterization forms the basis for a powerful noninvasive technique for imaging the cardiovascular system. Images constructed in planes orthogonal to the axis of the heart allow cardiac structures to be reproducibly detected in serial studies and measured. The data acquisition techniques used at Massachusetts General Hospital are presented, along with examples of their application in a variety of cardiac diseases. Future prospects are illustrated with flow-encoded images and with surface coil techniques.

Aorta↗
PubMed1984

The F plasmid origin of transfer: DNA sequence of wild-type and mutant origins and location of origin-specific nicks.

The DNA sequence of the F plasmid origin of conjugal DNA transfer, oriT , has been determined. The origin lies in an intercistronic region which contains several inverted repeat sequences and a long AT-rich tract. Introduction of a nick into one of the DNA strands in the oriT region precedes the initiation of conjugal DNA replication, and the position of the strand-specific nicks acquired by a lambda oriT genome upon propagation in Flac-carrying cells has been determined. The nicks were not uniquely positioned, rather there was a cluster of three major and up to 20 minor sites: the biological significance of this observation is not yet fully clear. Nine independent point mutations which inactivate oriT function have been sequenced and found to alter one or other of two nucleotide positions which lie 14 and 19 bp to one side of the rightmost (as drawn) major nick site. These key nucleotides may lie in a recognition sequence for the oriT endonuclease, since mutations at these sites prevent nicking at oriT .

Base Sequence↗
PubMed1984

A generalized learning deficit in albino rats with early median raphe or pontine reticular formation lesions.

Recent studies suggest that lesions of the median raphe or pontine reticular formation in adult rats are associated with a nonspecific (generalized) learning impairment. The present study showed that lesions in the region of the median raphe or pontine reticular formation in 21 day old rats likewise produced a nonspecific learning impairment, as evidence by significant deficits on a visual discrimination, nonvisual incline plane discrimination, 3-cul maze, and three simple spatial problems. The finding that relatively large lateral pontomesencephalic lesions did not lead to deficient learning of any of these tasks indicates that lesion locus rather than lesion size is responsible for the production of the learning deficits observed in this study.

Animals↗
PubMed1984

Cortical mechanisms underlying acquisition of latch-box problems in the white rat.

Adult rats, previously subjected to bilateral frontal, parietal, occipital, frontocingulate or posterior cingulate ablations, were required to learn two discrete latch-box tasks (sliding a barrel-bolt to the right and elevating a hook). Those groups showing significant learning impairments had lesions to either the frontal cortex or frontocingulate cortex. The data suggest that the neocortical focus for latch-box deficits lies rostral to Level 8 on the Lashley brain diagram, while the frontocingulate focus for latch-box deficits lies within the prelimbic area.

Animals↗
PubMed1984

Survey of human rotavirus propagation as studied by electrophoresis of genomic RNA.

Rotavirus RNA isolated from three different environmental sources during the winter of 1981-1982 was analyzed by polyacrylamide gel electrophoresis. Our results demonstrate the presence of novel RNA patterns, the coexistence of multiple electrophoretic patterns in rotavirus isolated from samples from a given ward, and that spread of a given electropherotype is limited.

Child↗
PubMed1984

Effect of season of birth and of hemicastration on the histology of the testis of 6-month-old lambs.

Season but not hemicastration affected the cellular composition of the testis. Despite similar weight, the testicular histology differed markedly with season of birth. The number of Leydig cells and of Sertoli cells was greater in summer- than in winter-born lambs by factors of 2 and 1.5 respectively. Similarly the number of spermatogonia and their rate of production increased substantially in summer-born lambs. The rate of spermatid production was affected by both hemicastration and season. Season of birth exerted more modifications to testicular histology than did hemicastration.

Animals↗
PubMed1984

Single-beam radiotherapy knife. A practical theoretical model.

A feasibility study reveals that a standard linear accelerator, with only slight modification, can function in a manner similar to Leksell's multiple cobalt radiation device. A high radiation dose can be delivered to a 1-cm or 0.5-cm volume target with insignificant radiation effect on the surrounding tissue.

Models, Biological↗
PubMed1984

Thalamic mechanisms underlying acquisition of latch-box problems in the white rat.

Acquisition of a bolt latch and/or hook latch was impaired in rats with mediodorsal, ventromedial, lateral, ventrolateral, midline or parafascicular thalamic lesions, but not in rats with anterior or ventrobasal thalamic lesions. The results suggest that the motor thalamus may extend to territories beyond the ventrolateral nucleus.

Animals↗