OBJECTIVE: To investigate the effects of long-term levothyroxine (LT4) suppressive therapy on the heart and the effects of beta-blockade on cardiac functions. DESIGN: Twelve female patients receiving LT4, selected from a group of patients with TSH levels of 0.1-0.4 microU/ml, were evaluated. The control group consisted of 11 healthy subjects and 12 patients with TSH levels <0.05 microU/ml. METHODS: Cardiac evaluation consisted of a 12-lead electrocardiogram and an echocardiographic study. Left ventricular mass index (LVMI), isovolumetric relaxation time (IVR), left ventricular end systolic (LVESD) and diastolic diameters, early (VE) and late (VA) diastolic flow velocities and fractional shortening were evaluated. Exercise capacity was assessed with a bicycle ergometer. Both work load and maximal exercise time were measured. Atenolol was given to the patient group at a dosage of 50 mg/day for 3 months and evaluations were repeated. RESULTS: On basal evaluations, LVMI (96+/-17 vs 78+/-21 g/m(2)) and IVR (101+/-9 vs 91+/-4 ms) were found to be increased in the patients taking LT4 (P<0.01). LVESD was also lower than controls (P<0.05). A decrease in VE and an increase in VA were also observed in the patients (P<0.01). IVR decreased after atenolol (92+/-10 vs 101+/-9 ms, P<0.05). LVMI decreased and VE and VA improved but did not reach statistical significance after beta-blockade. Baseline work load and maximal exercise duration were significantly lower in the patients and improvements were observed after atenolol treatment. CONCLUSIONS: These results indicated that cardiac dysfunction may occur even when TSH is suppressed to 0.1-0.4 microU/ml with LT4. beta-blockade improved the cardiac functions.
S Gullu, F Altuntas, I Dincer, C Erol and N Kamel
R Emral, M Bastemir, S Gullu and G Erdogan
OBJECTIVE: The Chernobyl accident caused widespread effects across Europe and huge areas were radiocontaminated. The major impact of the accident on human health was a sharp increase in childhood thyroid carcinoma and autoimmune thyroid diseases in exposed populations. The thyroidal effects of the Chernobyl accident have been investigated in most European countries, except Turkey. The aim of the current study was therefore to determine the thyroidal consequences of the Chernobyl nuclear power station accident in a selected Turkish population. DESIGN: This study was designed as a sectional, area study, between October 2000 and March 2001, in two different regions of Turkey. According to the data of the Turkish Atomic Energy Authority, the eastern part of the Black Sea region was the most radiocontaminated area in Turkey at the time of Chernobyl accident, while Middle Anatolia was not seriously affected. Thus, Rize city, which is located in the eastern Black Sea region, served as a study area, and 970 adolescents, living in this region, comprised our study group (group R). On the other hand, Beypazari, which is located in Middle Anatolia, was chosen as the control region, and 710 adolescents living in this location were enrolled into the study as controls (group B). METHODS: During the study, thyroid ultrasounds were performed in all subjects and thyroid volumes were calculated. World Health Organization and International Council for Control of Iodine Deficiency Disorders criteria were used for the determination of goiter. Thyroid fine-needle aspiration biopsy with ultrasound guidance was performed when a nodule was detected. Blood samples for thyroid function tests and thyroid autoantibodies, and urine samples for urinary iodine excretion were collected from all subjects. RESULTS: Thyroid function tests were similar in both groups, but thyroid volumes were found to be higher in group B (13.93+/-5.04 vs 17.66+/-5.58 ml; P<0.001). The prevalence of goiter was found to be 28.25% in group R and 61.95% in group B (P<0.001). Thyroid nodules were determined in 6.28% of subjects in group R and 4.22% of subjects in group B (P=0.065). No malignant lesions were found in either of the regions. Although the percentage of autoantibody-positive subjects did not differ between groups (21.25% in group R vs 18.72% in group B), the mean anti-thyroglobulin level was found to be higher in group R (63.25+/-378.60 vs 51.97+/-333.32 IU/ml; P<0.001) and the mean anti-thyroid peroxidase level was higher in group B (24.14+/-219.09 vs 48.82+/-568.50 IU/ml; P<0.001). The iodine status of the selected regions was found to be significantly different (median urinary iodine excretion was 131 microg/l in Rize and 54 microg/l in Beypazari). CONCLUSIONS: Although there was a slight increase in nodule prevalence and thyroid antibody-positive subjects in the study group, it is hard to conclude that Turkey was affected by the Chernobyl accident. These results, at least the significant differences with regard to the prevalence of goiters between groups, may reflect the different iodine status of the selected regions.
S Gullu, H Keles, T Delibasi, V Tonyukuk, N Kamel and G Erdogan
OBJECTIVE: The aim was to evaluate the validity of current remission criteria in acromegaly, a random GH level of <2.5 microg/l, a glucose-suppressed GH level of <1 microg/l and a normal IGF-I level. DESIGN: In forty-one patients treated for acromegaly (23 males and 18 females, 20-69 years) and 94 healthy subjects (50 males and 44 females, 20-78 years), basal GH and IGF-I levels and nadir GH levels after 75 g oral glucose were evaluated in decade blocks; these were assayed by sensitive immunoradiometric assays. RESULTS: Basal GH levels varied widely from 0.022 to 10.4 in healthy subjects and were >2.5 microg/l in 19%. The mean post-glucose GH nadir was 0.067+/-0.009 microg/l (range 0.003-0.4 microg/l) and the upper limit of the GH nadir was 0.26 microg/l (means+2 S.D.) in healthy subjects. Thirty-five patients with acromegaly had high-for-age IGF-I levels in relation to our healthy subjects. In this group, 15 (42.9%) patients had basal GH levels of <2.5 microg/l, 14 (40%) patients had nadir GH levels of <1 microg/l, and three (8.6%) patients had GH suppression to <0.26 microg/l which was defined as normal GH suppression in our healthy subjects. Only six patients with acromegaly had normal-for-age IGF-I levels and all of these patients had basal GH levels of <2.5 microg/l and all but one had nadir GH levels of <0.26 microg/l. CONCLUSIONS: A basal or random GH level of <2.5 microg/l is not a reliable criterion for remission in acromegaly and the currently accepted normal upper limit of 1 microg/l for post-glucose GH suppression is too high. Post-glucose nadir GH levels, measured with sensitive assays, can be <1.0 microg/l in 40% and basal GH levels can be <2.5 microg/l in 43% of the active acromegalic patients. IGF-I levels appeared to correlate better with a nadir GH cut-off of 0.26 microg/l rather than 1 microg/l in the determination of disease activity.