Search PubMed⌕ Search

Biomedical subjects

G Hamilton

Publications and source records attributed to G Hamilton.

At least 217 records · Page 12Linked to original sources
PubMed1990

A comparison of verapamil and nifedipine on quality of life.

1. Aspects of quality of life (symptoms, psychological well-being and activity) were evaluated by self-administered questionnaires in a 4 month randomised double-blind trial of titrated doses of verapamil slow release (n = 41) compared with nifedipine retard (n = 40). An untreated diastolic blood pressure of 95-115 mm Hg was required for inclusion in the trial. 2. The mean age in both groups was 55 years. A significant difference between the two drugs was found in the average reporting of symptoms with an increase on nifedipine (P less than 0.01). The reporting of swollen ankles and flushing (P less than 0.05) increased on nifedipine, and nocturia (P less than 0.05) increased on verapamil. Measures of psychiatric morbidity tended to improve on verapamil and deteriorate on nifedipine. Only the change in cognitive function was significant between the drugs, being worse on nifedipine (P = 0.05). 3. There was no difference between the two groups in the fall in diastolic blood pressure (average 18 mm Hg on nifedipine and 17 mm Hg on verapamil). There was a significantly greater fall in systolic blood pressure on nifedipine (23 mm Hg) compared with verapamil (13 mm Hg) (P less than 0.01). 4. The two drugs differed in their effects on measures of quality of life. The improvements in symptomatic complaints and psychological well-being on verapamil may have been due to inclusion in a trial, although we cannot exclude the possibility of a drug effect. Conversely the increase in symptoms and self-assessed cognitive impairment on nifedipine were considered to be side-effects of the drug.

Adult↗
PubMed1990

Office design.

Explore the source record for details and available documents.

Dental Offices↗
PubMed1989

A comparison of sclerotherapy with staple transection of the esophagus for the emergency control of bleeding from esophageal varices.

We compared two procedures for the emergency treatment of bleeding esophageal varices in patients who did not respond to blood transfusion and vasoactive drugs. We randomly assigned 101 patients with cirrhosis of the liver and bleeding esophageal varices to undergo either emergency sclerotherapy (n = 50) or staple transection of the esophagus (n = 51). Four patients assigned to sclerotherapy and 12 assigned to staple transection did not actually undergo those procedures, but all analyses were made on an intention-to-treat basis. Total mortality did not differ significantly between the two groups; the relative risk of death for staple transection as compared with sclerotherapy was 0.88 (95 percent confidence interval, 0.51 to 1.54). Mortality at six weeks was 44 percent among those assigned to sclerotherapy and 35 percent among those assigned to staple transection. Complication rates were similar for the two groups. An interval of five days without bleeding was achieved in 88 percent of those assigned to staple transection and in 62 percent of those assigned to sclerotherapy after a single injection (P less than 0.01) and 82 percent after three injections. In only 2 of the 11 patients who received a third sclerotherapy injection was bleeding controlled for more than five days, and 9 died. We conclude that staple transection of the esophagus is as safe as sclerotherapy for the emergency treatment of bleeding esophageal varices and that it is more effective than a single sclerotherapy procedure. We currently recommend surgery after two injection treatments have failed.

Adolescent↗
PubMed1989

Variceal hemorrhage.

Explore the source record for details and available documents.

Esophageal and Gastric Varices↗
PubMed1989

Ewing's-sarcoma-associated HBA-71 tumor antigen represents a new differentiation marker of human thymocytes.

The monoclonal HBA-71 antibody recognizes a new human tumor-associated antigen of Ewing's sarcoma and peripheral neuroectodermal tumors, which is also expressed in some normal tissues, including thymus, islets of Langerhans, ependyme, adenohypophysis, Sertoli/Leydig and granulosa cells. Besides a tumor-specific reciprocal chromosomal translocation t (11:22), the expression of the HBA-71 antigen is the only marker which can be used for reliable differential diagnosis of these rare malignancies of childhood and adolescence among other small round cell tumors. The HBA-71 antigen is further characterized here by ultrastructural, functional and cell-matrix interaction studies. In immunohistochemical staining the HBA-71 reacted with the cell surface of human cortical thymocytes. The HBA-71 antigen was also found to be localized at the cell-surface glycocalyx of tumor cells using immunogold staining and electron microscopy. A panel of additional monoclonal antibodies with reactivity patterns similar to those of the HBA-71 antibody was obtained by immunization of mice with ES cell lines and boostering with thymocytes. The HBA-71 antibody triggers proliferation of thymocytes and to a lesser extent also stimulates peripheral mononuclear blood cells. Antibody-induced thymocyte cultures exhibit the phenotype of immature, CD3low thymocytes with uniform and stable expression of the HBA-71 antigen. In contrast to the thymocytes the HBA-71 antibody has an inhibitory effect on the continuous growth of the HBA-71+ tumor cell lines. The HBA-71 antigen may be involved in the regulation of growth of the positive normal and malignant tissues. Positive modulation of the antigen expression was induced in Ewing's sarcoma cell lines in response to insulin, insulin-like growth factor I (IGF-I) and by interaction of the cells with the extracellular matrix.

Animals↗
PubMed1989

Expression of a new human THY-1 related antigen in Ewing's sarcoma and peripheral neuroectodermal tumors.

Ewing's sarcoma (ES), peripheral neuroectodermal tumor (PNET) and Askin's tumor of the chest wall share a reciprocal chromosomal translocation between the long arms of chromosomes 11 and 22 (q23-24; q12). In the absence of other distinguishing features this specific translocation is regarded as marker of a common and neuroectodermal origin for these rare tumors. A monoclonal antibody (HBA-71) developed in our laboratory has been found to recognize an unique ES and PNET associated antigen, which is also expressed in some normal tissues, including thymus, bone marrow, islets of Langerhans, ependyma and adenohypophysis. It is shown in this study that this HBA-71 antigen is closely related to the murine THY-1 antigens, major cell surface glycoproteins of thymocytes and brain in mice and rat. Both antigens have similar molecular ratios (18,000), amino acid compositions and sensitivity to tryptic digestion, show high cell surface expression, and binding of the appropriate antibodies to HBA-71 antigen triggers proliferation in thymocytes. The HBA-71 epitope may represent a primitive neuroectodermal marker of ES/PNET, or its expression may be directly linked to the reciprocal translocation invariably associated with HBA-71-positive ES and PNET tumors, which maps to the same region of chromosome 11 (q23-24) as the human Thy-1 gene.

Amino Acids↗
PubMed1989

Response of skin photoplethysmography, laser Doppler flowmetry and transcutaneous oxygen tensiometry to stenosis-induced reductions in limb blood flow.

Photoplethysmography (PPG), transcutaneous oxygen tensiometry (TCpO2) and laser Doppler flowmetry (LDF) were used to measure changes in perfusion of the distal lower limb of the pig, in response to a stenosis created in the external iliac artery. The severity of stenosis was quantitated by the ratio of peak systolic distal pressure to peak systolic proximal pressure (distal systolic pressure index, DSPI). PPG and LDF were immediately responsive to changes in perfusion pressure while TCpO2 responded much more slowly. PPG dropped precipitously in response to even a small reduction in perfusion pressure, reaching zero at a DSPI of approximately 0.3. TCpO2 was insensitive to the presence of a mild stenosis (DSPI greater than 0.6), but was highly sensitive in the range 0.6 greater than DSPI greater than 0.3. At lower DSPI values, TCpO2 also became zero, due in part to electrode consumption of oxygen. LDF readings were sensitive to changes in blood flow throughout the entire range of stenosis, down to the point of total occlusion, although changes were not significant at DSPI values greater than 0.6. Because LDF measures not only nutritional blood flow, but flow in AV shunts and subdermal plexuses as well, high LDF readings could erroneously suggest tissue viability and good healing potential. Resting levels of TCpO2 and LDF can be used to follow the progress of peripheral vascular disease, and used complementarily, in many cases, to evaluate the severity of flow impairment.

Animals↗
PubMed1989

Two-dimensional Doppler echocardiographic flow imaging--exploration of clinical impact and problems.

Recent advances in electronic engineering have allowed Doppler echocardiography to be presented in the form of a real-time two-dimensional image. The resulting image of blood flow has been described as a 'non-invasive angiogram', but the analogy with angiography should not be pushed too far since the technical determinants of these images are entirely different. Nevertheless, the colour flow map does allow rapid and direct exclusion, detection and quantitation of regurgitant and stenotic lesions, and semi-quantitative assessment of valvular regurgitation and shunts. To achieve optimum results, it is necessary to standardise recording procedure, to take account of patient variables which influence the image appearance and quality and to be aware of the possibility of artefact. As for all investigations, results which are not coherent with other echocardiographic data, with other investigations and with the clinical assessment should be subjected to particular scrutiny with the possibility of false diagnosis in mind.

Echocardiography, Doppler↗
PubMed1989

[Selective effect of personality markers and psychosocial stress on T lymphocyte subpopulations].

Measurements were made of cellular immune system parameters in a group of healthy medical students. On the basis of psychosocial stress encountered during a five-day topic-centered self-awareness course, we investigated modulation in immunity in relation to personality characteristics. 6 days before the beginning of the seminar personality profiles were drawn and blood samples taken. Further immunological measurements were made on day four of the seminar and three weeks after its conclusion. On the fourth day of the seminar we observed throughout the group higher lymphocyte and suppressor/cytotoxic T lymphocyte counts in comparison with counts one week earlier, and likewise a heightened responsiveness to PHA- and IL-2 stimulation. The T lymphocyte counts had dropped. In subjects with a higher need for succorance/nurturance, the depression of the immune system was manifested in a drop in the helper/inducer T lymphocyte counts, and in the more achievement- and order-oriented subjects in a downregulation as observed by higher suppressor/cytotoxic T lymphocyte counts. Our results show that under psychosocial stress, healthy people experience on the one hand an activation of the immune system, and on the other hand an immunodepression bearing a specific relation to personality characteristics.

Adult↗
PubMed1989

Atherosclerotic renovascular disease causing renal impairment--a case for treatment.

Renovascular disease is a potentially curable cause of renal failure. In a prospective survey over an eighteen month period atherosclerotic renal artery disease was the cause of renal failure in 14% of patients over the age of fifty years accepted for renal replacement therapy at this hospital. Ten patients were found to be suffering from atherosclerotic renovascular disease causing renal failure but in only one was treatment able to reverse renal failure. The major problem with this group of patients is the widespread nature of their disease affecting many other organs. Significant morbidity is associated with their investigation. Although potentially curable, atherosclerotic renovascular disease is a frequent cause of renal failure in patients over the age of fifty years but is also difficult to treat.

Aged↗