Biomedical subjects
K D Burman
Publications and source records attributed to K D Burman.
Thyrocyte specific killer cell activity is decreased in patients with thyroid carcinoma.
Natural killer cells (NK) are important in immune surveillance, and they have found to be decreased in the serum of patients with various types of malignancies. In patients with thyroid carcinoma, we investigated NK activity of peripheral lymphocytes directed against either a standard tumor cell target, K562, or against the clinically relevant target cell, the thyrocyte. Although NK-cell activity was normal when directed against K562 cell targets, NK-cell activity was reduced when labeled thyrocytes were used as target cells. At effector to target cell ratios of 100:1 and 20:1, there was 43 +/- 3% (n = 7) and 29 +/- 3% (n = 7) lyses of thyrocytes using normal lymphocytes, and 17 +/- 4% (n = 5) and 13 +/- 2% (n = 3) using lymphocytes from patients with thyroid carcinoma. These findings suggest that NK-cells have distinct subpopulations and that immune surveillance against specific thyrocyte target cells may be important in thyroid cancer.
Demonstration by immunoblotting of heterogeneity in the autoantibody response directed against fat cells in Graves' disease.
Guinea pig fat cell membranes (FCM) have been widely used in preference to thyroid membranes as a source of TSH receptors to investigate TSH receptor antibodies in Graves' disease, because FCM are ostensibly free of other thyroid antigens. However, by FCM immunoblotting we have found: 8 of 10 normal sera bound to determinants at 38 and 190 kDa; 17 other determinants were recognised by 60% of Graves' or Hashimoto sera and by 20% of normal sera; three determinants at 65-90 kDa were recognised by 5 of 13 Graves' but by none of the normal or Hashimoto sera; and none of the determinants recognised appeared to be related to the TSH receptor.
Intrinsic abnormality of thyroid cells from a patient with a Brobdingnagian goiter.
Thyrocytes from normal and goitrous portions of the thyroid gland from a patient with an enormous (635 gm) goiter were cultured in media, and their relative abilities to uptake thymidine, synthesize DNA, and secrete Tg and T4 were assessed. Tg, T4 and the ratio Tg/T4 in media at 72 h were 120 micrograms/dl, 1.6 micrograms/dl and 75 for normal cells, and 410 micrograms/dl and 273 for goitrous cells. DNA synthesis was 30-100% greater in goitrous than normal cells over a period of 72 h indicating abnormally high rates of cell division and growth, but their thymidine uptake was only 20% of that in normal cells. TSH elicited stimulation of thymidine uptake and DNA synthesis both in goitrous and in normal cells, but to a lesser extent in goitrous cells. No evidence of growth stimulating autoantibody activity was detected in the patient's serum. These data indicate that although the ability of goitrous cells to uptake thymidine was impaired, their DNA synthesis was more active than normal thyroid, which may have led to disordered cell growth as evidenced by the enormous goiter size in this patient. Although goitrous cells secreted more than three times as much Tg into media compared to normal, media T4 levels were similar, indicating an increased synthesis yet low iodination of Tg in goitrous cells. There does not appear to be any support for TGSI mediation of the goiter in this patient, but rather, the goiter may have been due to an intrinsic alteration in DNA synthesis resulting in vigorous cell growth.
Heterogeneity of thyroid autoantigens identified by immunoblotting.
Autoimmune thyroid disease in man is commonly associated with autoantibodies against thyroglobulin, microsomes, and the TSH receptor, and the character and specificity of these antithyroid antibodies have been extensively utilized in investigating these conditions. In the present study we have asked whether other thyroid-related antigens exist, against which autoantibodies may be directed. A crude thyroid extract was separated by polyacrylamide gel electrophoresis followed by immunoblotting with serum obtained from patients with Graves' disease or Hashimoto's thyroiditis. Antibodies in sera from patients with Graves' disease and Hashimoto's thyroiditis reacted with many antigenic determinants in immunoblots of the thyroid membrane preparation (2000g supernatant). These determinants were disease specific in that sera from normals and patients with Addison's disease and rheumatoid arthritis did not react, but there was no difference between the patterns of reactivity with Graves' disease or Hashimoto's thyroiditis sera. Thyroglobulin produced two predominant bands of reactivity at 320 and 200 kDa, whereas purified microsomal antigen produced a triplet of bands around 105 kDa, when these preparations were reacted with appropriate autoimmune sera. Nonetheless, some sera produced additional bands with the microsomal antigen blots, indicating that some of the antigens which were detected using crude thyroid membrane remained in the microsome preparation to produce multiple antibody binding reactivities. We were unable to inhibit any of the antibody binding with TSH. Purification of individual thyroid antigens on the basis of their molecular weights should standardize current antibody assays and permit more detailed evaluation of the cellular immune responses in Graves' disease and Hashimoto's thyroiditis.
Angiotensin-converting enzyme activity decreases during fasting.
UNLABELLED: Serum angiotensin-converting enzyme (ACE) activity varies directly with thyroid hormone levels in states of altered thyroid function. Because T3 levels decrease during fasting, ACE activity was examined to ascertain if it was reduced in this low T3 condition. Eighteen obese euthyroid subjects were hospitalized and placed on a weight-maintaining diet for 4 days. Nine subjects (Group 1) underwent a fast (50 kcal/day) for 8 days. Nine (Group 2) subjects received T3 (5 micrograms q 3 h) during an identical fast. Weight loss was identical in both groups (-4.4 kg). Serum T3 fell in Group 1 from 104 +/- 8 to 50 +/- 4 ng/d/(p less than .05) but was unchanged in Group 2 (114 +/- 11 ng/dl fed vs. 120 +/- 14 ng/dl fasted). Blood pressures fell significantly in Group 1 (mean systolic: 112----104 mmHg; diastolic: 71----65 mmHg, p less than 0.05), but not in Group 2 subjects. ACE activity fell progressively in Group 1 subjects during fasting (14.4 +/- 1.6 U/ml fed vs. 12.8 +/- 1.4 U/ml fasted p less than 0.05). ACE activity was not decreased significantly early in the fast in patients given T3, but by late fast (days 6-8) was reduced to the same degree as in Group 1 subjects. Glucose and insulin levels fell similarly in both groups. CONCLUSIONS: (1) ACE activity is reduced during starvation. This effect is not mediated by T3. (2) Blood pressure reduction during fasting may result from the low T3 levels, but not from decreased ACE activity. Interpretation of serum ACE activity must be viewed in the context of a patient's diet.
Iodide administration enhances thyrotrophin responsiveness to thyrotrophin-releasing hormone during fasting: evidence for normal pituitary feedback regulation.
Short-term fasting in humans is associated with diminished delta TSH to TRH. The purposes of the present study were to reassess basal TSH levels and TRH responsiveness during fasting utilizing a sensitive radioimmunoassay (RIA: sensitivity 0.3 microU/ml; normal range 0.66-2.98 microU/ml) and to determine if normal feedback regulation is maintained during the fasting state. Eight control subjects (C) and six iodide-treated (I) subjects (262 mg/d) were studied in the fed state and on day 10 of fasting. T3, T4, and TSH were measured by RIA, and free T4 and free T3 by equilibrium dialysis. Basal serum TSH levels in the control group were 2.0 +/- 0.3 microU/ml (mean +/- SEM) in the fed state and increased to 14.7 +/- 3.5 microU/ml 20 min after TRH administration. The fasting basal TSH level of 1.6 +/- 0.3 microU/ml was significantly decreased (P less than 0.01) compared to control, as was the level of 8.8 +/- 2.3 microU/ml (P less than 0.01) obtained 20 min after TRH. In the iodide-treated group the basal TSH level was 1.4 +/- 0.2 microU/ml during feeding which increased (P less than 0.025) to 2.9 +/- 0.7 microU/ml during fasting; the TSH value 20 min after TRH was 12.6 +/- 2.5 microU/ml while feeding and 17.3 +/- 2.9 microU/ml while fasting. Free and total T3 decreased during fasting in both groups. Total T4 was unchanged between the fed and fasted periods in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Antibodies to porcine eye muscle in patients with Graves' ophthalmopathy: identification of serum immunoglobulins directed against unique determinants by immunoblotting and enzyme-linked immunosorbent assay.
The immunological mechanisms involved in Graves' ophthalmopathy are not known. To explore the pathophysiology of this disorder, we used an enzyme-linked immunosorbent assay to detect antibodies that bound to the 100,000 X g sediment fraction of porcine eye muscle. Serum from patients with Graves' ophthalmopathy had enhanced immunoglobulin binding to porcine eye muscle compared to serum from control subjects (P less than 0.0001); however, several individual normal serum samples also had elevated binding activity. Incubation of serum from some Graves' patients with skeletal muscle or liver tissue resulted in reduction in immunoglobulin binding to porcine eye muscle. Thyroglobulin and TSH reduced binding only at high concentrations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed some obvious differences in protein bands between porcine eye muscle and skeletal muscle. Serum from many normal subjects and patients with autoimmune thyroid disease formed bands with skeletal muscle protein fractions on immunoblotting, and no specific bands were found using serum from Graves' ophthalmopathy patients. Immunoblots of Graves' patients' serum after reaction with either porcine skeletal or eye muscle showed no reactivity with thyroglobulin (200K and 320K) or thyroid microsomal antigen (105K). Instead, immunoblots of eye muscle and serum from Graves' patients, with or without eye disease, showed two bands at 64K and 73K, which were shared by serum from normal subjects. In addition, several unique eye muscle determinants were detected in serum from 6 of 13 Graves' disease patients analyzed. These unique bands usually had mol wt of less than 50K, and 5 of the 6 patients whose serum reacted with these determinants had significant ophthalmopathy. Our findings support the presence of potential antigenic differences between eye muscle and skeletal muscle accounting for the immunological specificity of eye muscle as a target in Graves' ophthalmopathy.
Remission rates with antithyroid drug therapy: continuing influence of iodine intake?
We retrospectively reviewed the therapeutic efficacy of antithyroid drugs for Graves disease. Sixty-nine patients were divided into three categories according to their response: 28 (40.6%) were unable to achieve a remission; 6 (8.7%) achieved a remission and subsequently had a relapse; and 35 (50.7%) were able to sustain a remission. The mean duration for sustained remissions was 33 months. Our earlier review of outcome of antithyroid therapy showed markedly reduced remission rates, which appeared to be related to increases in dietary iodine intake. Although the greater percentage of patients entering remission today is in marked contrast to the 1973 report, average dietary iodine content has been decreasing. A continuing role for antithyroid drugs should be maintained as an option in the management of Graves disease. Daily dietary iodine intake may influence the anticipated remission rate after antithyroid drug therapy.
Persistent thyroid autoimmunity after subacute thyroiditis.
Subacute (de Quervain's) thyroiditis (SAT) is accompanied by temporary abnormalities in thyroid function and, in a minority of patients, by transient thyroglobulin and thyroid microsome autoantibody formation. In this report we have examined the sera of patients with SAT for the presence of multiple thyroid autoantibodies using qualitative immunoblotting (Western blotting). For this purpose we used a crude thyroid extract (2,000 g supernatant) as a source of antigen, in order to identify antibodies reacting with a wide range of potential autoantibodies. Eight of the 9 patients tested had autoantibodies which reacted with between 2-18 antigenic determinants (molecular weights 177-10 kd) present in the thyroid antigen preparation. None of the sera reacted with thyroglobulin or thyroid microsomes. The majority of these autoantibodies were directed against antigens which were absent from liver membrane preparations. Furthermore there was no diminution in the levels of these autoantibodies over a period of up to 39 months after the onset of SAT. The prolonged presence of these novel thyroid autoantibodies may explain the recent findings of subtle thyroid defects, such as altered gland iodine content, long after apparent clinical resolution of SAT. The accumulated evidence for a viral aetiology in this condition suggests that these sequelae may be due to a virally-induced autoimmune response.
The role of T lymphocytes in autoimmune thyroid disease.
Abnormalities in cellular mechanisms of immunoregulation are important factors in the initiation and/or propagation of autoimmune thyroid disease and Graves' ophthalmopathy. The primary immunologic lesion, however, remains elusive despite increasingly sophisticated investigations in the areas of antigen presentation and subsequent T-cell responses. Emphasis on functional evaluations of relevant cell populations and advances in lymphokine analysis, interpretation of DR antigen expression, and T-cell cloning offer promise for our future understanding of this complex process.
c-myc expression in the thyroid. I: Normal, adenomatous, and cancerous thyroid tissue.
Recent investigations have suggested that myc oncogene expression may be important in the development or progression of thyroid tumors. The purposes of the present study were to assess cellular (c)-myc expression in thyroid adenomas (n = 5), as well as in thyroid cancer (n = 4) and in normal thyrocytes (n = 7). Total RNA was prepared by extraction with guanididium thiocyanate and ultracentrifugation through a CsCl2 cushion. 30 micrograms total RNA was size fractionated on a 1% (w/v) agarose/formaldehyde gel and transferred to nylon membranes. These membranes were hybridized to a 32P-labelled third exon c-myc DNA. Following hybridization, blots were washed under high stringency and subjected to autoradiography; radioautographic bands were assessed visually or were quantitated by scanning densitometry. Nodular tissue had approximately the same degree of expression of the 2.4 Kb c-myc message as the surrounding normal tissue from the same gland (0.66 +/- 0.09 vs. 1.0 +/- 0.26, respectively); normal thyrocytes were capable in every instance of expressing the 2.4 Kb c-myc message. Thyroid cancer tissue expressed this message (0.91 +/- 0.17) but only at a level comparable to normal tissue. No other bands of hybridization were detected in any samples. We conclude that c-myc oncogene expression is comparable in normal thyrocytes and in thyroid nodules or thyroid cancer samples. These findings support a role for c-myc in both normal and neoplastic thyrocyte growth.
c-myc expression in the thyroid. II: Thyrocytes and peripheral and intrathyroidal lymphocytes from patients with autoimmune thyroid disease.
Enhanced oncogene expression observed in lymphocytes from patients with systemic lupus erythematosus has suggested the importance of studying oncogene expression and regulation in the cellular events of autoimmune thyroid diseases (AITD). The present study examines oncogene expression in peripheral and intrathyroidal lymphocytes from patients with Hashimoto's disease (HD) and Graves' disease (GD). Intrathyroidal lymphocytes from a patient with primary thyroid lymphoma were also examined. Lymphocytes were isolated by Ficoll-Hypaque gradients, and total RNA was prepared by extraction with guanididium thiocyanate and ultracentrifugation through a cesium chloride cushion. RNA concentrations were determined by O.D. readings at 260/280 nm and each sample subjected to gel electrophoresis with ethidium bromide staining to assure the integrity of the RNA. 30 micrograms total RNA was size fractionated on a 1% (w/v) agarose/formaldehyde gel and transferred to nylon membranes. These membranes were hybridized with nick-translated 32P labelled c-myc DNA (exon III), washed at high stringency and subjected to autoradiography. Specific bands were quantitated by scanning densitometry. Five RNA samples from GD thyroids had 2.4 Kb bands corresponding to c-myc with a mean O.D. (+/- SD) of 0.76 +/- 0.23, whereas 7 from normal thyroid glands had mean O.D. of 1.0 +/- 0.26. Peripheral lymphocytes from 7 GD patients had a mean O.D. of 1.41 +/- 0.25, 4 HD patients had a mean O.D. of 1.05 +/- 0.10 and 2 normal patients had a mean O.D. of 1.4 +/- 0.14. The readings for a sample obtained from intrathyroidal lymphocytes of a patient with HD and thyroid lymphoma were 1.0 and 1.4, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Lithium-associated thyrotoxicosis.
Primary hypothyroidism developed in a 57-year-old woman treated for eight years with lithium carbonate for manic-depressive illness, and nine months later she became thyrotoxic. Although autoimmune disease appeared to be responsible, lithium was suspected to play a contributory role in both phases of her illness. This is the first reported case of hyperthyroidism following hypothyroidism in a lithium-treated patient. The 24 reported cases of lithium-associated thyrotoxicosis and the possible mechanisms that may explain this poorly understood phenomenon are also reviewed.
The production and characterization of thyroid-derived T-cell lines in Graves' disease and Hashimoto's thyroiditis.
Although the thyroid gland itself is a major site of the autoimmune response, the study of T-cell function in autoimmune thyroid disease has usually relied on peripheral blood as a source of cells. In this study, we have established thyroid-derived T-cell lines from six patients with Graves' disease and one patient with Hashimoto's thyroiditis by culturing the thyroid lymphocytes on an autologous thyroid follicular cell monolayer in the presence of exogenous interleukin 2 (IL-2). These T-cell lines have allowed in vitro investigation of thyroid-derived T-cell function, an approach which was previously limited by the number of lymphocytes obtained from the gland. The lines were predominantly OKT3, OKT4, and HLA-DR positive but showed heterogeneous proliferative responses. Some lines gave autologous or allogeneic mixed lymphocyte reactions but other did not. Only one of the seven lines responded well to the thyroid antigens thyroglobulin and microsomes presented by autologous monocytes. However, six of the lines proliferated in the presence of live but not dead autologous thyroid follicular cells, particularly when interferon-gamma (IFN-gamma) was added. This treatment has been shown to enhance HLA-DR and -DQ antigen expression by thyroid follicular cells in vitro. Furthermore, the proliferation induced by IFN-gamma-treated thyroid follicular cells was increased when thyroglobulin was also added. Together these results support the hypothesis that the expression of Ia antigens such as HLA-DR by thyroid follicular cells in autoimmune thyroid disease may be important in enhancing the autoimmune response, conferring on these cells the ability to present thyroid autoantigens to T cells. The use of thyroid-derived T-cell lines should permit a more detailed evaluation of the disordered immuno-regulation in Graves' disease and Hashimoto's thyroiditis than has been possible previously.
Alterations in the hypothalamic-pituitary-thyroid axis after prolonged residence in Antarctica.
The human population which lives and works in polar environments has been increasing steadily over the last 15 years. Very little is known about how these residents adjust to their environment. Cold adaptation in man is a poorly understood phenomenon. Euthermic mammals maintain body temperature during cold exposure via non-shivering thermogenesis, a process which is hormonally mediated. We studied prospectively the response of the hypothalamic-pituitary-thyroid axis in 17 euthyroid men before, during and after assignment to duty in the Antarctic. Serum total and free T4 levels fell slightly but not significantly after very prolonged Antarctic residence. Serum total and free T3 decreased significantly from basal levels of 170 +/- 3 ng/dl and 388 +/- 19 pg/dl to 155 +/- 5 ng/dl and 319 +/- 14 pg/dl respectively after Antarctic duty. Serum T3 levels increased after 42 weeks of polar living, the end of the observation period, but the change did not attain statistical significance. The integrated TSH response to TRH administration increased by 50% to 734 +/- 58 microIU.min/ml over warm climate basal response levels of 456 +/- 33 microIU.min/ml by the end of the study. The daily circadian rhythm of serum cortisol was maintained throughout the study period. The alterations in thyroid hormones which we describe, are apparently related to the chronic cold exposure which our subjects experienced in this polar environment.
Killer cell activity and antibody-dependent cell-mediated cytotoxicity are normal in Hashimoto's disease.
Antibody-dependent cell-mediated cytotoxicity (ADCC) is the process by which antibodies interact with killer cells to effect cell lysis, whereas natural killing (NK) refers to the ability of peripheral blood killer cells to lyse target cells in the absence of specific antibody. The purpose of the present study was to determine if either NK cells or ADCC might play a role in the development of Hashimoto's thyroiditis (HD) by testing the ability of killer cells to cause lysis of K562 erythroleukemia tumor cells and human thyrocytes in the presence and absence of serum from normal and HD patients. Using K562 target cells, NK activity was 70 +/- 4% (mean +/- SEM) for HD effector cells and 66 +/- 5% for normal effector cells at an effector to target ratio of 100:1. Similarly, with thyrocytes as targets, effector cells from HD patients (38 +/- 3%) and normal subjects (34 +/- 5%) caused comparable lysis (at an effector to target ratio of 100:1). Using K562 target cells, ADCC was 35% when effector cells from HD or normal subjects were coincubated with either normal or HD sera. Using thyrocyte target cells, lysis was about 25-30%, but, again, no differences were found between HD and normal effector cells or serum. There was a significant correlation between lysis for K562 and thyrocyte target cells, but there was no significant correlation between the titer of serum antithyroid microsomal antibodies and specific lysis. Intrathyroidal lymphocytes and peripheral lymphocytes from one patient with HD caused comparable lysis of labeled thyrocyte targets, as did normal peripheral lymphocytes. We conclude that ADCC and NK activities in peripheral lymphocytes were normal in HD patients and, therefore, may not have a primary role in mediating thyrocyte destruction in Hashimoto's thyroiditis.
L-thyroxine dosage: a reevaluation of therapy with contemporary preparations.
Traditional L-thyroxine dosing formulas may overestimate the thyroid hormone requirement in patients treated with contemporary L-thyroxine preparations. We did clinical and laboratory assessments of 41 patients treated in successive periods with Levothroid (Armour Pharmaceuticals, Kankakee, Illinois) and Synthroid (Flint Division, Travenol Laboratories, Morton Grove, Illinois), obtaining 87 sets of data. Clinical subgroups were defined on the basis of the thyrotrophin response to thyrotrophin-releasing hormone. Normal responses were seen in 9 of 14 (64%) patients taking 100 micrograms/d and were associated with an average replacement dosage of 127 micrograms/d (1.7 micrograms/kg body weight). Nine of twenty-eight (32%) serum thyroxine values in the "physiologically replaced" group were elevated. Forty-three of fifty-four (80%) patients ingesting 125 micrograms or more had blunted responses (thyroxine "overreplaced"), averaging a daily dosage of 154 micrograms (2.14 micrograms/kg X d). No significant difference was found between Levothroid and Synthroid in predicting clinical group assignment. Guidelines for currently available L-thyroxine preparations should be revised and the recommended dosage reduced.