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Biomedical subjects

R Hall

Publications and source records attributed to R Hall.

At least 325 records · Page 18Linked to original sources
PubMed1985

Proteinuria in autoimmune thyroid disease.

We have investigated the prevalence of proteinuria in patients with Graves' disease and chronic autoimmune thyroiditis attending a routine thyroid clinic. Using the urine protein creatinine index, proteinuria was found in 29.8% of patients with autoimmune thyroid disease and in 9.5% of patients attending the same clinic but without these conditions. When patients with Graves' disease were treated with 131I, proteinuria measured by 24 h collections developed in 9 of 14 patients without pre-existing proteinuria and appeared to diminish in 4 patients in whom proteinuria had been present before treatment. The prevalence and fluctuation of proteinuria was independent of thyroglobulin and microsomal antibody levels. We were unable to confirm previous reports of a high prevalence of circulating immune complexes in autoimmune thyroid disease; complexes were detected in only 7.9% of patients and did not correlate with proteinuria. The causes of mild proteinuria in autoimmune thyroid disease are not apparent, but previous case reports suggesting that membranous glomerulonephritis is associated with Graves' disease, albeit rarely, indicate that immunological mechanisms may be implicated.

Adult↗
PubMed1985

The production and characterization of monoclonal antibodies to the human thyroid microsome.

By suitable immunization of mice and fusion of their spleen cells with a non-secretor mouse myeloma line, monoclonal antibodies have been produced which react with the human thyroid microsomal (M) antigen. These monoclonal antibodies showed no reactivity by enzyme-linked immunoassay with liver microsomes or thyroglobulin and their specificity was confirmed by immunolocalization studies, in which they showed the staining characteristics of human M antibodies. All four monoclonal antibodies tested were immunoglobulin M; three were cytotoxic to thyroid cell monolayers. The lack of cytotoxicity with the fourth monoclonal supports the concept that certain epitopes of the M antigen may be partially or completely absent at the thyroid cell surface. These monoclonal antibodies should permit further characterization of the thyroid M antigen in view of their absence of cross-reactivity with thyroglobulin.

Animals↗
PubMed1985

An enzyme-linked immunosorbent assay for the measurement of thyroglobulin in human serum using mouse monoclonal antibodies.

A robust, rapid, sensitive and specific enzyme-linked immunosorbent assay (ELISA), using an in-house immunoglobulin-A-sub-class mouse monoclonal human-thyroglobulin antibody (WNSM2), with a sensitivity of 1.51 pmol/l has been established for the measurement of thyroglobulin in serum. Standard curves in varying dilutions of human serum were similar to standard curves obtained in serum-free medium, thus demonstrating no significant cross-reactivity with any serum proteins other than thyroglobulin. Levels of serum thyroglobulin detected by ELISA correlated significantly (r = 0.93, P less than 0.001) with those from a standardized and well-characterized radioimmunoassay. The coefficients of variation within and between ELISA assays were 3.9 and 7.1% respectively. Thyroglobulin was detectable in 87% of 54 normal subjects who had no history of thyroid or autoimmune disease, the mean (+/- S.D.) for this group being 15 +/- 6.6 pmol/l with a range of 1.51-53 pmol/l. Using this assay, levels of thyroglobulin were shown to be significantly (P less than 0.002) increased in patients with untreated hyperthyroid Graves' disease compared with normal subjects.

Animals↗
PubMed1985

Experience in implementation of clinical guidelines: pre-operative chest radiography in non-cardiopulmonary surgery.

In 1983, the All-Wales Management Efficiency Group (All-Wales MEG) published a report on pre-operative chest radiography (POCR) and made recommendations about the use of POCR in district health authorities in Wales. The object of this paper is to describe experience within one Welsh authority, highlighting both perceived problems and the difficulties encountered in the implementation of these recommendations.

Hospitals↗
PubMed1985

The influence of lithium chloride on experimental autoimmune thyroid disease.

Lithium administration is known to be associated with the development of thyroid dysfunction; it also exerts an effect on the immune system. The effect of lithium on experimental autoimmune thyroid disease was studied in female August rats. Following immunization with rat thyroglobulin in Freund's complete adjuvant, lithium chloride was administered i.p. for 30 days to four groups at varying stages of the disease. Control animals received i.p. saline. Anti-thyroglobulin antibody levels (measured by ELISA) were significantly increased in rats given lithium immediately post-immunization (group B) compared to control animals (661 +/- 42 OD vs 448 +/- 68; mean +/- s.e., P less than 0.02). In contrast, animals which received lithium during the spontaneous resolution of the disease (group D) showed a significant fall in anti-TG antibody compared to controls (99 +/- 15 vs 27 +/- 15; P less than 0.001). Anti-TG antibody levels remained undetectable in animals which received lithium but were not immunized. The splenic T cell blastogenic response (as measured following phytohaemagglutinin stimulation) was significantly increased in rats receiving lithium prior to and during immunization (group A) (stimulation index 63.4 +/- 6.9 vs 10.2 +/- 2.4; P less than 0.001). Spontaneous cell proliferation of splenic lymphocytes was decreased in two lithium treated groups (group A P less than 0.005, group C P less than 0.05). There was no alteration in splenic weight or the degree of thyroid lymphocytic infiltration in any of the treated group. Lithium exerted both positive and negative influences on the immune system in rats immunized with thyroglobulin in adjuvant but did not induce autoantibody production in normal rats.

Animals↗
PubMed1985

Thyroid autoantigen-induced lymphocyte proliferation in Graves' disease and Hashimoto's thyroiditis.

Further progress in understanding T-cell interactions in autoimmune thyroid disease would be possible if T-cell lines and clones could be established. We have therefore examined peripheral blood lymphocyte proliferation in response to a variety of thyroid antigens in Graves' disease and Hashimoto's thyroiditis. A number of different culture conditions were used but in all cases the frequency and magnitude of positive responses were low, the maximum stimulation found for any individual culture with antigen being less than 4-fold above background proliferation. In addition we have examined the blastogenic response of Graves' lymphocytes from thyroid, cervical lymph node and thymus. Positive responses were again found but the stimulation produced by antigen was only 3-fold above background. These results are compatible with recent findings in experimental autoimmune thyroiditis and suggest either that very few antigen-specific T cells are involved in the autoimmune process or that antigen-specific cells exist which can suppress the proliferative response in vitro. It therefore seems unlikely that randomly collected peripheral blood T cells from patients with autoimmune thyroid disease can be sufficiently stimulated by thyroid autoantigens to establish lines or clones without additional manoeuvres such as fractionation into subsets.

Antigens↗
PubMed1985

The management of patients with acute myocardial infarction after successful reperfusion with streptokinase.

Intracoronary streptokinase administration has been an effective procedure for establishing reperfusion of an evolving myocardial infarction by lysing the thrombus that is usually responsible for the infarction. After reperfusion is accomplished, appropriate management of the patient must be planned to provide the best chance for assuring continued vessel patency, and appropriate management of the patient's residual coronary artery disease also must be considered. In selected patients, percutaneous transluminal coronary angioplasty of the residual coronary lesion has been performed successfully immediately following reperfusion with streptokinase. Early coronary artery bypass graft surgery has been performed with good results in other patients. The appropriate management of the patient with acute myocardial infarction is still evolving, and only with additional study and experience will the "best" approach in the management of these patients be defined.

Adult↗
PubMed1985

The influence of cyclosporin A on the induction of experimental autoimmune thyroid disease in the PVG/c rat.

Using an experimental model of autoimmune thyroid disease we have investigated the influence of cyclosporin A (CyA) on the induction of the disease and its potential ability to prevent disease development. PVG/c rats (n = 80) neonatally thymectomized (day 21) and thence sublethally irradiated were divided into eight groups and received either no CyA or oral CyA (10 mg/kg body weight) for varying periods prior to and during disease induction. Serial serum measurements of thyrotropin (TSH) by radioimmunoassay and anti-thyroglobulin autoantibody by enzyme linked immunosorbent assay showed a progressive rise in untreated animals. The rise in serum TSH levels from 349 +/- 15 ng/ml (mean +/- s.e., normal less than 400 ng/ml) at 7 weeks of age to 526 +/- 61 ng/ml at 11 weeks and 820 +/- 54 ng/ml at 15 weeks was not significantly different in animals treated with CyA for periods ranging from 24 h prior to thymectomy to 7 days post-thymectomy. In contrast animals treated for 28 days post-thymectomy showed significantly lower levels of TSH at both 11 weeks (391 +/- 26; P less than 0.02) and 15 weeks (587 +/- 37; P less than 0.005) as compared with untreated animals. Similar though less dramatic changes were seen in intermediate groups. Autoantibody levels in untreated animals rose from initially undetectable levels to 0.451 +/- 0.07 OD (mean +/- s.e.) at 11 weeks and 0.581 +/- 0.041 OD at 15 weeks. Animals treated for at least 4 weeks after thymectomy with CyA had significantly lower levels of antibody at both 11 weeks (0.213 +/- 0.01; P less than 0.001) and 15 weeks (0.337 +/- 0.03; P less than 0.001) of age. Intermediate groups ranged in antibody levels depending on the duration of CyA treatment. Thyroid gland weight (12.7 +/- 2.4 mg/100 g body weight, mean +/- s.e.) and histological grade of thyroiditis (1.8 +/- 0.4, mean +/- s.e.) in the animals treated with CyA for 4 weeks, assessed when the animals were killed at 15 weeks, were smaller and had less severe thyroiditis than untreated thymectomized and irradiated animals (23.8 +/- 2.8 mg/100 g, P less than 0.02 and 2.9 +/- 0.2, P less than 0.05) killed at the same time. CyA given for long enough during induction of experimentally-induced autoimmune thyroid disease delayed the onset of disease and reduced its severity but could not prevent it given over time courses ranging from 48 h prior to thymectomy to 4 weeks after.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Surgical treatment of pneumatosis coli.

This report is of five cases of primary pneumatosis coli, four of whom underwent five surgical resections. Follow-up was from nine months to ten years with one recurrence nine years after sigmoid colectomy. This experience indicates that primary pneumatosis coli is now more common than pneumatosis cystoides intestinales of the small bowel. We also feel that there is a place for surgical resection of symptomatic pneumatosis coli even in the absence of acute complications.

Adult↗
PubMed1984

Comparison between videotape and personal teaching as methods of communicating clinical skills to medical students.

The efficacy of video recording in transmitting clinical knowledge and skills to medical students was tested by recording on videotape demonstrations of physical examinations given by five clinicians to a randomly selected group of 12 students (personal group) from the first clinical year and then showing these recordings, under identical conditions, to 13 students from the same year (video group). The efficacy of both the personal and video mediums in terms of whether content was retained was tested by a questionnaire completed by all students at the end of the sessions and by a structured clinical assessment in which students were asked to demonstrate some of the same clinical tasks three weeks after the demonstration. In answering the questionnaire the video group obtained a mean (SD) score of 20.8 (7.0) (maximum possible score 40), which was not significantly different from the score achieved by the personal group (17.4 (7.7)). The video group was able to reproduce 44 (10)% of the total clinical steps demonstrated and the personal group 45 (14)%. Videotaped demonstrations can be as effective as personal teaching of clinical methods, and video should be developed as a medium for first line clinical teaching.

Clinical Competence↗
PubMed1984

The effects of long term growth hormone releasing factor (GRF 1-40) administration on growth hormone secretion and synthesis in vitro.

The ability of human pancreatic GH releasing factor 1-40 (hpGRF 1-40) to release GH has been studied in rat anterior pituitary cells in primary culture. Over 24 hours hpGRF (1-40) increased total (cell content and secretion) production 2-fold with an ED50 of 20 pM. Subsequent hpGRF (1-40) stimulation of GH release was not affected by pretreatment when the fall in stored GH was taken into account. In contrast LH responses to gonadotrophin releasing hormone (GnRH) were markedly desensitized after 24 hours GnRH pretreatment in the same experimental system and using the same analysis. hpGRF (1-40) responses were not desensitized when pretreatment was for 3, 12 or 24 hours. The data show that hpGRF (1-40) responses do not desensitize in our experimental conditions under which GnRH responses show marked desensitization.

Animals↗
PubMed1984

Enzyme-linked immunoassay of monoclonal and serum microsomal autoantibodies.

An automated enzyme-linked immunoassay for the detection of antibodies to human thyroid microsomes has been assessed. This assay correlated closely with the established commercial passive haemagglutination method. Variations in the purity of crude microsome preparations and the degree of thyroglobulin contamination make careful comparison of different preparations essential for meaningful interpretation of results, and attempts to circumvent these problems by further purification of microsome preparations using gel filtration are discussed. The application of this method for routine screening of serum samples is demonstrated using populations of normal subjects and patients with rheumatoid arthritis and anti-glomerular basement membrane disease. This assay has also permitted the establishment of murine hybrid myelomas secreting monoclonal antibodies to human thyroid microsomes.

Adult↗
PubMed1984

Methimazole and generation of oxygen radicals by monocytes: potential role in immunosuppression.

A study was conducted investigating the possibility that the immunosuppressive action of methimazole (the active metabolite of the antithyroid drug carbimazole) might be due to an effect on the production of oxygen radicals by monocytes. Techniques comprised measurement of luminol dependent chemoluminescence in monocytes and a spectrophotometric assay for production of hydrogen peroxide. The results showed definite inhibition of formation of oxygen radicals by resting and stimulated monocytes, which may explain the immunosuppressive action of the drug in Graves' disease. The findings also suggest that the formation of oxygen radicals and the initiation of the immune response may be closely related.

Cells, Cultured↗
PubMed1984

Analysis of T cell subsets in Graves' disease: alterations associated with carbimazole.

Conflicting data on subpopulations of peripheral blood lymphocytes in patients with autoimmune disease largely reflect variations in methods of study. An investigation was therefore conducted aimed at avoiding this difficulty. Serial samples of peripheral blood mononuclear cells from 42 patients with hyperthyroid Graves' disease were collected at monthly intervals before, during, and for 12 months after a six month course of carbimazole. Samples were stored in liquid nitrogen until completion of the study, when they were thawed and all samples from each patient analysed within the same assay using mouse monoclonal antibodies to human cell subsets and a fluorescence activated cell sorter. Proportions of cytotoxic/suppressor (OKT8) positive cells before treatment (mean 17.4 (SEM 0.8)%) were significantly lower (p less than 0.001) than those in normal controls (29.8 (1.9)%; n = 10) and returned to normal by the end of treatment. In contrast, the proportions of activated T cells (OKIa-OKM1) were significantly raised before treatment as compared with normal (14.4 (0.6)% versus 4.6 (0.8)%; p less than 0.001) and fell to normal by the end of treatment. Proportions of OKT3 and OKT4 positive T cells remained unchanged throughout treatment and in the succeeding 12 months. In patients who relapsed after treatment there was a rise in the proportion of activated T cells and a fall in OKT8 positive T cells, which returned towards normal with retreatment. The explanation for the alterations in numbers of circulating T cells remains to be determined but they may provide a means for predicting more accurately the outcome of Graves' disease after treatment with carbimazole.

Antibodies, Monoclonal↗