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Biomedical subjects

D A Koutras

Publications and source records attributed to D A Koutras.

At least 37 records · Page 2Linked to original sources

Mitral valve prolapse in autoimmune thyroid disease: an index of systemic autoimmunity?

A coexistence of mitral valve prolapse (MVP) with autoimmune thyroid disease (AITD) has been described, but there are not sufficient data to explain this association. The aim of the present study was to investigate the prevalence of MVP in patients with AITD and to evaluate whether any correlation between MVP and certain immunological parameters exists. M-mode, two-dimensional Doppler echocardiography was performed in 29 patients with Graves' disease (GD), 35 with Hashimoto's thyroiditis (HT), 20 with nonautoimmune goiter, and 30 normal controls. Serum samples were examined for antinuclear antibodies (ANA), antibodies against extractable nuclear antigen (ENA), antiphospholipid antibodies (aCL), rheumatoid factor (RF), thyroid autoantibodies (TAAb), immunoglobulins and C3, C4. Eight of 29 GD patients and 8 of 35 HT patients had MVP, while none of the control group and 2 of 20 of the simple goiter group had MVP (p < 0.05). ANA were detected at low titers in 5 of 8 in MVP(+) GD versus 3 of 21 in MVP(-) GD (p < 0.05). In the HT group the MVP(+) patients had a significantly higher incidence of ANA and ENA, 5 of 8 and 2 of 8 versus 5 of 27 and 0 of 27 of MVP(-) patients, respectively, p < 0.05. A statistically significant higher incidence of aCL was found in HT MVP(+) patients. (3/8) versus HT MVP(-) 1/27, p < 0.05. RF levels (immunoglobulin A [IgA]) were significantly higher in MVP(+) patients. The association of MVP with nonorgan-specific autoantibodies indicates that MVP may also be an autoimmune disease. It is possible that patients with AITD who also have MVP may be at an increased risk to develop systemic autoimmunity.

Adult↗

Experimental nephritis: one of the earliest publications on the subject by a pioneer of Neohippocratism.

From the beginning of the 20th century, cumulative experimental work has provided considerable evidence for the possible immune mechanisms by which certain diffuse glomerular diseases develop. The first classic well-documented studies are attributed to Masugi and his research team (1933), whose experimental model involved the induction of glomerulonephritis by the administration of antikidney sera. However, 23 years earlier, in 1910, Alexander Cawadias had published a monograph on the same subject, for which he was honored with the Medal of the Paris University School of Medicine. In his study, Cawadias concluded that the mechanism of experimental nephritis was multifactorial and that the progression and the aggravation of uremic disease was caused by the production of nephrotoxins and/or antibodies against renal tissue. Cawadias referred to 'a new colloid substance', a kind of autoantibody in the context of anaphylaxis; he can be credited with foreseeing the modern era of the autosensitivity and immunology of renal diseases. Although Cawadias is well-known as a pioneer of Neohippocratism, his contribution to experimental nephritis has not been amply appreciated; he merits better recognition as one of the pathfinders in the field of renal immunopathogenesis.

Animals↗

Fas ligand expression in thyroid carcinomas: a potential mechanism of immune evasion.

Fas ligand (FasL) induces apoptosis by cross-linking the Fas receptor and is expressed by cells of the immune system. Recently, FasL was found in malignant tumors, suggesting that it helps them escape immune surveillance by eliminating infiltrating lymphocytes. We investigated the presence of FasL immunohistochemically in 48 thyroid carcinomas and by Western blotting and RT-PCR in 5 thyroid carcinoma cell lines. We found that in contrast to normal thyroid tissue, FasL was highly expressed in all papillary, follicular, and Huerthle carcinomas. Medullary carcinomas lacked or had minimal FasL expression. In papillary carcinomas, high levels of expression correlated independently with aggressive histology and unfavorable clinical presentation. FasL was also present in all thyroid cell lines. Thyroid carcinoma cells killed Fas-sensitive targets in a FasL-dependent manner in a coculture experiment. Cross-linking of Fas induced apoptosis in thyroid carcinoma cells only in the presence of cycloheximide. We conclude that FasL is specifically expressed in thyroid carcinomas of follicular epithelial origin, may help them evade the immune system, and may have prognostic implications in papillary carcinoma, as it is associated with a more aggressive phenotype. Thyroid carcinoma cells avoid Fas-mediated suicide possibly by expressing an inhibitor of the Fas apoptotic pathway.

Adolescent↗

The predominant form of non-toxic goiter in Greece is now autoimmune thyroiditis.

Endemic non-toxic goiter (NTG) in Greece has been attributed primarily to iodine deficiency. Thirty years ago about 60% of the prepubertal boys and girls examined in endemic goiter regions presented with NTG and among them thyroid autoimmunity was rarely detected. Although iodine supplementation has corrected this deficiency during the past 30 years, new cases of NTG still appear. To evaluate the prevalence and type of NTG and the effect of iodine supplementation on them in Greece at present, we performed two cross-sectional clinical studies and a retrospective pathology one: (i) thyroid gland volume and urinary iodine excretion (UIE) were assessed in a representative sample of 1213 schoolchildren from previously endemic and non-endemic regions; (ii) serum thyroxine, tri-iodothyronine, TSH, thyroid autoantibodies (AAB) (anti-thyroid peroxidase and anti-thyroglobulin antibodies) and UIE (in 60 patients) were measured in 300 consecutive patients with NTG from Athens and Heraklion; and (iii) we compared the prevalence of autoimmunity among fine needle aspiration smears of benign thyroid pathologies performed by the same pathologist between 1985 and 1986 (975 cases) and between 1994 and 1995 (2702 cases). We found that 12. 5% of the schoolchildren examined in regions with a previous history of endemic goiter had NTG, whereas this percentage was only 1.7% in areas without such a history. In Athens (61.6%) and Heraklion (58. 5%) a substantial number of NTG patients were AAB positive and biochemically hypothyroid. UIE in Athens did not differ between patients with autoimmune goiter (ATG) and simple goiter. The prevalence of autoimmune stigmata in pathology smears has increased from 5.94% (years 1985-1986) to 13.91% (years 1994-1995) (P<0.05). We conclude that: (i) the persistence of endemic goiter in regional foci despite iodine deficiency correction suggests a possible role for a naturally occurring goitrogen; (ii) ATG is the predominant form of NTG in Greece nowadays; and (iii) the five-fold decrease in the prevalence of NTG during the past 30 years followed by the increase of ATG may support the relative character of the latter.

Autoantibodies↗

Thyroid disease associated with rheumatoid arthritis is not adequately screened with a sensitive chemiluminescence thyrotrophin assay.

The objective of this study was to screen for thyroidopathies in patients with rheumatoid arthritis (RA). Screening for thyroid disorders is advocated in patients with autoimmune diseases, and rheumatoid arthritis has been linked to thyroid autoimmune disorders, more particularly Hashimoto's thyroiditis and sometimes Graves' disease. We performed thyroid disease screening in 69 patients with RA free of medication for at least a 2 weeks period, not in remission, and in 65 patients with osteoarthritis (OA). The latter were studied as a control group of non-autoimmune arthritis patients. Basal levels of thyrotrophin (TSH) were measured using a sensitive chemiluminescence serum TSH assay. Serum antithyroperoxidase and antithyroglobulin (anti-Tg) autoantibodies were measured as well. If TSH values were found to be outside the normal limits, serum total thyroxine, total triiodothyronine (T3), resin T3 uptake, the free thyroxine index (FT4I) and free triiodothyronine index (FT3I) were evaluated. Rheumatoid arthritis patients exhibited statistically significant lower mean TSH values as compared to OA patients. However, RA patients with low TSH values did not have elevated FT4I. Previous use of corticosteroids in some of the RA patients may be responsible for these results. The autoantibodies levels did not differ between the two groups. We conclude that thyroid function screening with sensitive TSH assays is not sufficient for assessment of early stages of autoimmune thyroidopathies in patients with RA. Thyroid hormones should also be estimated.

Arthritis, Rheumatoid↗

Macrovascular disease of coronaries and cerebral arteries in streptozotocin-induced diabetic rats. A controlled, comparative study.

The aim of this study was to demonstrate the macrovascular disease in streptozotocin-induced diabetic rats and assess any possible differences between the histopatholological changes of the coronaries and cerebral arteries. Hearts and brains were obtained after 4 weeks (short-term experimental diabetes, 10 rats) and 12 weeks (long-term experimental diabetes, 10 rats) of streptozotocin injection. Sham injected, control rats were studied in parallel. Muscular-type arteries of 0.10-0.15 mm were examined and semiquantitatively classified either as normal, or slightly, or moderately, or severely thickened by light microscopy: While the arterial wall appeared normal in all sham-injected rats, a varying degree of hyperplasia of the muscular layer and deposition of fibrinoid material resulting in arterial stenosis was prominent in streptozotocin-injected rats. In the group of short-term diabetes there was a slight thickening of the cerebral arteries in the majority of the rats (8/10 rats), while thickening of the coronaries was moderate (9/10 rats). Further progression of arterial wall thickening in both cerebral and coronary arteries was observed in the long-term diabetic group. The mean severity of lesions was significantly higher in the coronaries than in cerebral arteries, both in the short-term (p < 0.0005) and long-term diabetes (p < 0.02). Moreover, by paired statistics within individual animals, we confirmed that wall thickening was significantly more severe in coronaries than cerebral arteries in both groups. These findings suggest an accelerated progress of macrovascular disease in the heart as compared to the brain in the streptozotocin-induced diabetic rat. Although histopathological changes in humans do not always mirror clinical severity, the differences in the macrovascular disease between heart and brain in experimental diabetes may be relevant to the higher relative risk of myocardial infarction compared to stroke for people with diabetes, as compared to people without diabetes.

Animals↗

Inhibitory action of oral thyrotropin-releasing hormone on the glucoregulatory response of the oral glucose tolerance test.

Thyrotropin-releasing hormone (TRH) has been found in the gastrointestinal tract, where it mainly exerts an inhibitory action. We used oral TRH, a stable and powerful formulation, to explore the glucoregulatory response of oral glucose tolerance test (OGTT) on obese patients with impaired glucose tolerance (IGT). Seven obese patients with IGT and eight controls were investigated. Three tests were performed on three separate days. On day 1, An oral TRH test: a 40 mg TRH tablet, was given. Blood samples for blood glucose (BG), proinsulin (PI), insulin (INS), C-peptide (CP), thyroxine (T4), triiodothyronine (T3), and thyrotropin (TSH) were collected every 30 minutes for 3 hours. On day 2, an OGTT with 75 g glucose was performed. On day 3, an oral TRH test was administered 30 minutes before the OGTT, and blood was collected every 30 minutes for 3 hours. Oral-TRH had no effect on basal BG and on pancreatic hormone secretion. Oral TRH, coupled with OGTT in both controls and obese patients, led to a significant inhibition of BG (p < 0.01), of CP (p < 0.001), and of INS (p < 0.001) during the first hour of administration, and afterward, there was only a very slight increase, compared with levels after only OGTT treatment. After OGTT, PI peaked at 90 minutes (9.4+/-3 ng/mL) in controls and at 60 minutes (12.7+/-2.5 ng/mL) in obese patients. TRH application prior to OGTT inhibited PI secretion for 90 minutes in controls, whereas in obese patients PI levels were decreased, not inhibited, during the OGTT. The mechanism of the inhibitory TRH action on OGTT-induced increase of BG and pancreatic hormone secretion is not clear. It could be due to inhibition of gastric motility, and on a paracrine effect that enhances secretion of somatostatin that then suppresses INS, CP, and possibly PI levels. The partial escape of PI from the TRH blockade in obese patients with IGT might indicate a diminished functioning capability of beta-cells and that TRH cannot affect the INS processing within the beta-cells in these patients.

Adult↗

Fas/Fas ligand up-regulation and Bcl-2 down-regulation may be significant in the pathogenesis of Hashimoto's thyroiditis.

Hashimoto's thyroiditis (HT) is an autoimmune disorder characterized by diffuse thyroid lymphocytic infiltration and follicle destruction. Cross-linking of the Fas receptor with its own ligand (FasL) triggers apoptosis in various systems, whereas the Bcl-2 protooncogene inhibits apoptotic cell death. The involvement of Fas, FasL, and Bcl-2 in the apoptotic process in HT was evaluated in 15 thyroid tissue samples from patients with HT stained for apoptosis and for Fas, FasL, and Bcl-2 protein expression. Eight samples from healthy thyroid tissue were used for comparison. Thyroid follicles in HT samples exhibited strong staining for Fas and FasL and a high percentage of apoptosis (30.3 +/- 14.5%, mean +/- SD), in contrast to normal control follicles that exhibited moderate Fas, minimal or no FasL, and hardly any apoptosis. Immunostaining for Bcl-2 was high in normal, and weak in involved, thyroid follicles. Infiltrating lymphocytes stained weakly for FasL and strongly for Bcl-2. We conclude that follicular cells in HT undergo apoptosis by concomitant up-regulation of FasL and Fas and down-regulation of Bcl-2 protein. The lymphocytes do not seem to be directly engaged in the process with their own FasL, but they may provide the appropriate cytokine milieu that, in turn, up-regulates Fas and/or FasL leading to apoptosis.

Adolescent↗

High serum cholesterol levels in persons with 'high-normal' TSH levels: should one extend the definition of subclinical hypothyroidism?

OBJECTIVE: The association between established hypothyroidism and high cholesterol levels is well known. The aim of the present study was to investigate the effect of thyroxine (T4) administration on cholesterol levels in hypercholesterolemic subjects with TSH levels within the normal range ('high-normal' TSH compared with 'low-normal' TSH). DESIGN AND METHODS: We determined TSH levels in 110 consecutive patients referred for hypercholesterolemia (serum cholesterol >7.5 mmol/l). Those with 'high-normal' TSH (2.0-4.0 microU/ml) as well as those with 'low-normal' TSH (0.40-1.99 microU/ml) were randomly assigned to receive either 25 or 50 microg T4 daily for two months. Thus, groups A and B (low-normal TSH) received 25 and 50 microg T4 respectively and groups C and D (high-normal TSH) received 25 and 50 microg T4 respectively. Serum T4, tri-iodothyronine (T3), TSH, free thyroxine index, resin T3 uptake and thyroid autoantibodies (ThAab) as well as total cholesterol, high and low density lipoprotein cholesterol (HDL, LDL), and triglycerides were determined before and at the end of the two-month treatment period. RESULTS: TSH levels were reduced in all groups. The most striking effect was observed in group D (TSH levels before: 2.77+/-0.55, after: 1.41+/-0.85 microU/ml, P < 0.01). Subjects in groups C and D had a higher probability of having positive ThAabs. A significant reduction in total cholesterol (P < 0.01) and LDL (P < 0.01) was observed after treatment only in group D. In those subjects in group D who were ThAab negative, there was no significant effect of thyroxine on cholesterol levels. CONCLUSIONS: Subjects with high-normal TSH levels combined with ThAabs may, in fact, have subclinical hypothyroidism presenting with elevated cholesterol levels. It is possible that these patients might benefit from thyroxine administration.

Adult↗

Disturbances of menstruation in thyroid disease.

Both hyper- and hypothyroidism may result in menstrual disturbances. In hyperthyroidism, amenorrhea was described as early as 1840 by von Basedow. The most common manifestation is simple oligomenorrhea (decreased menstrual flow). Anovulatory cycles are very common. Increased bleeding may occur, but is rare in hyperthyroidism. Nowadays hyperthyroidism is diagnosed earlier than it once was, and so the clinical picture is generally milder. So, menstrual disorders are less common than in previous series. In a recent paper, 21.5% of 214 patients had disturbances in their cycle, compared to 50% in some older series. In hypothyroidism, on the contrary, polymenorrhea (increased menstrual bleeding) is more common. Defects in hemostasis may contribute to this. Anovulation may be represent. Fertility is reduced in both hyper- and hypothyroidism, and the outcome of pregnancy is more often abnormal than in euthyroid women. It is of interest that in juvenile hypothyroidism precocious puberty has been described. This is probably due to a "spillover" effect of the glucoprotein hormones: TSH, which is markedly increased in hypothyroidism, has a small FSH- and LH-like effect. Galactorrhea may also be present in hypothyroidism, possibly because TSH, the hypophyseal TSH-releasing hormone, increases the secretion of both TSH and PRL.

Anovulation↗

Genetic screening for RET mutations in families with multiple endocrine neoplasia 2 syndromes.

Mutations in the RET proto-oncogene have recently been recognized to be responsible for the inherited multiple endocrine neoplasia type 2 syndrome. As expected, Greek patients with MEN2 and FMTC carry RET mutations similar to those of other ethnic groups. In those regions of the gene that were analyzed, mutations were detected in six out of six families with classical MEN2A, three out of five of the families with familial MTC, and one case with MEN2B. Presymptomatic screening using DNA analysis has now replaced calcitonin stimulation tests in the offspring of families where the mutation has been characterized. The use of these methods will improve the prognosis in MEN2 patients and will also reduce the psychological burden of risk for a potentially lethal disease on family members.

Drosophila Proteins↗

Endothelial dysfunction of conduit arteries in insulin-dependent diabetes mellitus without microalbuminuria.

OBJECTIVE: Previous studies have shown that endothelial dysfunction, an early sign of atherosclerosis, occurs in animal models of diabetes mellitus and in resistance vessels of patients with insulin-dependent diabetes. In the present study we examined whether young patients with insulin-dependent diabetes without microalbuminuria present abnormal endothelial function of large peripheral arteries. METHODS: Twenty-six patients with insulin-dependent diabetes without microalbuminuria were compared with 26 normal controls and 5 patients with insulin-dependent diabetes with microalbuminuria. Brachial artery diameter was measured at rest, during reactive hyperaemic flow (endothelium-dependent dilatation) and after sublingual isosorbide dinitrate (endothelium-independent dilatation). RESULTS: Baseline artery diameter and flow as well as the degree of reactive hyperaemia were similar in all groups compared to controls. Flow-mediated dilatation was lower in patients with diabetes without microalbuminuria (5.8 +/- 7 vs 11 +/- 7%. P = 0.01) as well as in patients with diabetes without microalbuminuria (0.75 +/- 2.5 vs 11 +/- 7%, P = 0.003); nitrate-induced dilatation was normal in patients without microalbuminuria and attenuated in patients with microalbuminuria. In the group of diabetes patients without microalbuminuria, those with disease duration > 10 years and HbAlc > 6% had the worse endothelial function. CONCLUSIONS: Our results demonstrate that endothelial dysfunction of conduit arteries can be detected in patients with insulin-dependent diabetes mellitus without microalbuminuria, probably contributing to the high prevalence of atherosclerosis in these patients.

Adolescent↗

Flow-mediated, endothelium-dependent vasodilation is impaired in subjects with hypothyroidism, borderline hypothyroidism, and high-normal serum thyrotropin (TSH) values.

Patients with hypothyroidism are considered to have an increased risk of developing atherosclerosis; because endothelial dysfunction is an early sign of atherosclerosis, we investigated whether endothelial dysfunction is present in patients with hypothyroidism. Thirty-five subjects with various TSH levels were investigated by high-resolution ultrasound imaging of the brachial artery to assess endothelial and smooth muscle responses. Flow-mediated, endothelium-dependent vasodilatation was significantly higher in subjects with TSH 0.4-2 microIU/mL (11.8 +/- 2.7%), compared with subjects with TSH 2.01-4 microIU/mL (6.8 +/- 2.9%), 4.01-10 microIU/mL (5.2 +/- 6.3%) and >10 microIU/mL (4.0 +/- 4.4%); TSH levels correlated inversely to endothelium-dependent dilatation. Thus, flow-mediated vasodilatation, a marker of endothelial function, is impaired not only in patients with mild hypothyroidism but also in subjects with "high-normal" serum TSH levels (ie, 2.01-4.0 microIU/mL) that may be characterized as possibly abnormal.

Adult↗

Hyperthyroidism in McCune-Albright syndrome with a review of thyroid abnormalities sixty years after the first report.

We present a patient with hyperthyroidism associated with McCune-Albright syndrome (MAS). MAS is a sporadic genetic disease characterized by polyostotic fibrous dysplasia, cafe au lait cutaneous spots and endocrinopathies (peripheral precocious puberty, thyroidopathies, acromegaly, etc.). It is caused by an activating mutation of the gene for the Gs alpha membrane-associated protein, which mediates the thyrotropin (TSH)-induced and other hormone-induced activation of adenylyl cyclase. A 13-month-old girl was diagnosed with MAS. Precocious puberty was treated initially with testolactone and later with oophorectomy. Subclinical hyperthyroidism was detected biochemically at birth, and 10 months later, it became clinically evident, albeit mild, with absence of goiter. A concomitant liver dysfunction precluded treatment with thionamides and she was sporadically treated with beta-blockers. The combination of increased free thyroxine (T4) and triiodothyronine (T3) with low plasma thyrotropin (TSH) levels in the absence of thyroid-stimulating autoantibodies persisted until the age of 6 years, when she was referred to our unit. Hyperthyroidism was then clinically evident with cardiac hyperactivity, and it was cured with administration of radioiodine (131I). Thyroid disease is the second most common endocrinopathy associated with MAS, and since 1936, 63 cases of thyroidopathies have been described, including 19 nodular (14 with and 5 without hyperthyroidism) and 23 diffuse (20 with and 3 without hyperthyroidism) goiters, and 18 cases of hyperthyroidism without goiter. The previously described somatic activating mutation of the gs alpha gene in the ovaries, the liver and the peripheral blood of our patient, in the absence of stigmata, autoimmunity might be incriminated for the secretory and mitotic activation of the thyroid gland. We suggest the treatment of choice of hyperthyroidism in MAS patients should be 131I administration because: (a) hyperthyroidism is very likely to recur after withdrawal of antithyroid medication; (b) the morbidity of these patients is elevated; (c) oophorectomized patients do not need to be advised to avoid procreation during the months after 131I administration; and (d) finally, even in the usual cases of hyperthyroidism in childhood, 131I treatment is becoming more popular worldwide.

Child↗

Simultaneous occurrence of a medullary and a papillary thyroid carcinoma in the same patient.

We present the case of a patient in whom we diagnosed two different thyroid carcinomas (one on each lobe) of distinct histologic type: one derived from the follicular cells (papillary) and one from the C cells (medullary). They were both diagnosed preoperatively by fine needle aspiration (FNA), and the diagnosis was confirmed with histologic examination. "Inappropriate" staining with neuroendocrine markers was observed in the papillary tumor. Analysis of tumor tissue for the RET oncogene mutations, commonly found in the MEN2 syndromes, was negative. This case supports the view of a common origin for these two tumor types.

Biopsy, Needle↗

Control of efficiency and results, and adverse effects of excess iodine administration on thyroid function.

The control of the efficiency and the results of iodisation programs can be done clinically, biochemically and by monitoring the side-effects. Clinical improvement (disappearance of all the manifestations of iodine deficiency disease) is the most important end-point. However, some manifestations may persist for life, and so clinical improvement may require a long time interval before becoming apparent. For this reason, biochemical control, especially the urinary iodine excretion, is the most important early sign of the success (or not) of the iodisation programs. Side-effects of iodine in general include: 1. Iodine-induced hyperthyroidism. An increase in toxic nodular goitre is probably transient and eventually its incidence is expected to decrease. However, an increased incidence of autoimmune Graves' disease is probably permanent. 2. Iodine-induced hypothyroidism. 3. Iodine-induced autoimmunity, both of the Hashimoto and of the Graves types. 4. An increase in the incidence of papillary cancers, probably with a decrease in the more aggressive types. In any case, the benefits of iodisation programs far outweigh the risks, provided they are implemented and monitored carefully.

Drug Overdose↗