Relation between lean body mass and thyroid volume in competition rowers before and during intensive physical training.

OBJECTIVE: Lean body mass is a better determinant of thyroid size than body weight as demonstrated in a previous crosssectional study. We now evaluated if intra-individual changes in body composition and especially changes in lean body mass, due to physical training, could give rise to changes in thyroid volume. SUBJECTS AND METHODS: We investigated 17 freshmen (group 1) before and after six months of competition rowing; controls (group II) were 19 senior rowers, already participating in a training program for more than 2 years. RESULTS: In group I body weight (BW; p < 0.01), lean body mass (LBM; p < 0.05), fat weight (FW; p < 0.05), body mass index (BMI; p < 0.01) and thyroid volume (TV; p = 0.08) all decreased; in group II body composition and thyroid volume did not change at all during the 6 months observation period. Whereas serum TSH and T3 did not change, free thyroxine (FT4) concentrations increased slightly in both groups (p < 0.01), presumably caused by the combination of exercise and insufficient energy intake. Taking together all subjects, baseline TV was directly related to BW (r = 0.35, p<0.05), to LBM (r=0.40, p<0.05) and to BMI (r=0.43, p < 0.01) but not to FW (r = - 0.06, NS). The decrease in thyroid volume was related to the decrease in LBM (r = 0.32, p = 0.05), in BW (r = 0.49, p < 0.005), in FW (r = 0.42, p = 0.01) and in BMI (r = 0.53, p = 0.001). CONCLUSIONS: After a six-month period of intensive physical training, changes in thyroid volume correlate directly with changes in body composition.

A randomized trial comparing levothyroxine with radioactive iodine in the treatment of sporadic nontoxic goiter.

A randomized clinical trial was performed in consecutive patients with sporadic nontoxic nodular goiter to compare efficacy and side effects of iodine-131 ((131)I) therapy with suppressive levothyroxine (L-thyroxine) treatment. Sixty-four patients were randomized after stratification for sex and menopausal age to receive (131)I (4.44 MBq/g thyroid; group A) or suppressive L-thyroxine treatment aiming at TSH values between 0.01 and 0.1 mU/L (group B). The main outcome measurements after 2 yr were goiter size by ultrasound, serum thyroid function tests, markers of bone turnover, and bone mineral density (BMD). Fifty-seven patients completed the trial. Goiter size was reduced after 2 yr by 44% in group A and by 1% in group B (P< 0.001). Nonresponders (goiter reduction <13%) were 1 of 29 patients in group A and 16 of 28 patients in group B (P = 0.00001). In responders, goiter reduction in group A (46%) was greater than in group B (22%; P< 0.005). In group A, 45% of patients developed hypothyroidism. In group B, 10 patients experienced thyrotoxic symptoms, requiring discontinuation of treatment in 2 (in 1 because of atrial fibrillation). Markers of bone formation and bone resorption increased significantly in group B, related to a mean decrease of 3.6% of BMD at the lumbar spine after 2 yr (from 1.09 +/- 0.22 to 1.05 +/- 0.23 g/cm(2); P< 0.001), both in pre- and postmenopausal women. No changes in BMD were observed in group A. In conclusion, (131)I therapy is more effective and better tolerated than L-thyroxine treatment in patients with sporadic nontoxic goiter. Suppressive L-thyroxine treatment results in significant bone loss.

Determinants of longterm outcome of radioiodine therapy of sporadic non-toxic goitre.

OBJECTIVE: Radioiodine treatment is effective in reducing the size of sporadic nontoxic goitre, albeit at the expense of a high incidence of postradiation hypothyroidism. The decrease in goitre size, however, is not observed in all subjects, and little is known about recurrent goitre growth after 131I therapy. The aim of the present study was to evaluate which factors determine the longterm outcome of 131I treatment in patients with sporadic nontoxic nodular goitre, in terms of changes in both thyroid size and thyroid function. STUDY DESIGN: Retrospective follow-up study. PATIENTS: Fifty patients with sporadic nontoxic nodular goitre were evaluated who had been treated in our institution with 131I (mean dose 4.4 MBq/g thyroid) in the period 1988-95. Nine patients received a second dose of 131I and one a third. Median follow-up time was 41 months (range 24-115). MEASUREMENTS: Thyroid function was assesed by TSH and FT4 index, and thyroid volume by ultrasound in 46 patients, by scintiscan using the Himanka formula in three and by CT-scan in one. The response to treatment was defined as a decrease in thyroid volume of greater than 13% (i.e. the mean + 2SD of the coefficient of variation of volume measurements), and recurrent goitre as an increase in thyroid volume greater than 13% after an initial response. RESULTS: Goitre size decreased from a median value of 82 ml (range 17-325) to 37 ml (range 6-204) two years after 131I treatment, a median reduction of 49%. The decrease in goitre size was directly related to the dose of 131I (r = 0.50, P = 0.0003) and indirectly to baseline goitre size (r = - 0.35, P = 0.006). Seven patients (14%) were nonresponders, and four (8%) experienced recurrent goitre growth after 3-5 years. These 11 patients (22%) when compared to the remaining 39 responders (78%) had larger goitres with more often a dominant nodule, and had received a lower 131I dose. The efficacy of a second dose of 131I (median reduction in goitre size 37%) was comparable to the first dose. Hypothyroidism occurred in 24 patients (48%), mostly in the first two years after treatment; 11 had overt and 13 subclinical hypothyroidism. Kaplan Meier statistics indicated a probability of 58% for developing hypothyroidism after 8 years. Hypothyroid patients had a smaller initial goitre size and a higher prevalence of TPO antibodies and a family history of thyroid disease than the patients who remained euthyroid; the 131I dose did not differ between the two groups. CONCLUSIONS: The size of sporadic nontoxic goitres is reduced on average by 50% after a single dose of 4.77 MBq 131I/g thyroid. Independent determinants of the relative decrease in thyroid volume are administered 131I dose and initial goitre size. Nonresponders (14%) and those with late recurrence of goitre growth (8%) have larger goitres and more often dominant nodules than responders. Determinants of postradioiodine hypothyroidism (cumulative risk 58% after 8 years) are the presence of TPO antibodies, a family history of thyroid disease and a relatively small goitre. The implications of these findings are that the efficacy of a given 131I dose can be enhanced when administered at an earlier stage when the goitre is still smaller, albeit at the expense of an increased risk for developing hypothyroidism.

Ultrasonographic versus scintigraphic measurement of thyroid volume in patients referred for 131I therapy.

The activity of 131I to be administered as therapy to patients with thyroid disease is usually calculated from 24 h radioiodine uptake and thyroid volume. The aim of the present study was to compare thyroid volume, measured by scintigraphy and ultrasonography, to evaluate the impact of these methods on the calculated 131I dose. Forty patients (20 with diffuse toxic goiter and 20 with multinodular toxic or nontoxic goiter) were investigated. On the same day, thyroid volume was measured by ultrasonography (using transverse scans at 5 mm intervals) and by scintigraphy, using either the ellipsoid formula (SC-E: [symbol: see text]/6 x height x width x depth) or the Himanka formula (SC-H: 0.33 x (planimetric surface in pixels)3/2). With ultrasonography, the size of diffuse goiters was smaller than that of nodular goiters (median values and range: 18 ml (11-46) and 50 ml (14-198) respectively, P < 0.001). Both scintigraphic methods, however, failed to demonstrate a significant difference between diffuse and nodular goiter size. In patients with diffuse goiter, thyroid volume measured by SC-E did not differ from that measured by ultrasonography, whereas thyroid size was overestimated by 53% using the Himanka formula. In contrast, in patients with nodular goiter, thyroid volume measured by SC-H did not differ from that measured by ultrasonography, whereas the ellipsoid formula underestimated thyroid size by 48%. The overestimation of diffuse goiter size by the Himanka formula resulted in a relatively modest median excess of 96 MBq (range -118 to +248 MBq) of the calculated 131I dose. The underestimation of nodular goiter size by the ellipsoid formula resulted in a calculated dose that was 278 MBq lower (range -1624 to +141 MBq). The median calculated 131I dose based on the Himanka formula was not different from that based on ultrasound, but large differences in calculated 131I dose (up to 1280 MBq) were found in individual cases. In conclusion, thyroid volume can be assessed with accuracy by scintigraphy using the ellipsoid formula in patients with diffuse goiter. Wide differences, however, are observed in the size of nodular goiters measured by scintigraphy and ultrasonography.

Lean body mass as a determinant of thyroid size.

OBJECTIVE: Males have a larger thyroid gland than females, and this has been related to the difference in body weight. In view of the different body composition of men and women, we hypothesized that lean body mass is a better determinant of thyroid volume than body weight. DESIGN: A cross-sectional study in an area not deficient in iodine. SUBJECTS: 44 non-obese healthy adults (group I, 21 men, 23 women with equal distribution of sexes in age groups between 21 and 70 years) and 20 adults with marked obesity (group II, 8 men, 12 women, BMI > 30 kg/m2) were studied. None used medication and all had normal thyroid function tests. MEASUREMENTS: Thyroid volume was measured by ultrasonography, and lean body mass with a body impedance analyser. RESULTS: The thyroid volume in men was larger than in women in both groups; it was also larger in the obese than in the non-obese subjects. In the nonobese subjects, thyroid volume was related both to body weight (r = 0.42, P < 0.005) and to lean body mass (r = 0.55, P = 0.0001). In the obese subjects, thyroid volume was no longer related to body weight (r = 0.23, NS) but was still correlated with lean body mass (r = 0.54, P = 0.01). Taking both groups together, the correlation between thyroid volume and lean body mass (r = 0.64, P < 0.001) was stronger than between thyroid volume and body weight (r = 0.50, P < 0.001). Thyroid volume was also related to body length (group I, r = 0.42, P < 0.005; group II, r = 0.54, P = 0.01), but to body-surface area only in the non-obese subjects (group I, r = 0.45, P < 0.01; group II, r = 0.38, NS). The larger thyroid size in the obese was associated with slightly but significantly higher TSH and lower free T4 serum concentrations as compared to the non-obese subjects. CONCLUSIONS: In healthy adults, lean body mass rather than body weight explains the differences in thyroid volume between males and females and between obese and non-obese subjects. Lean body mass appears to be a major determinant of thyroid size.

Identification and isolation of the indole-3-pyruvate decarboxylase gene from Azospirillum brasilense Sp7: sequencing and functional analysis of the gene locus.

The root-associated bacterium Azospirillum brasilense Sp7 produces the growth-stimulating phytohormone indole-3-acetic acid (= IAA) via the indole-3-pyruvate pathway. The DNA region containing ipdC, the structural gene for indole-3-pyruvate decarboxylase, was identified in a cosmid gene library of strain Sp7 by hybridization and has been sequenced. Upstream of the gene, two other ORF homologous to gltX and cysS were sequenced that are transcribed in the opposite direction. A functional analysis of the cloned ipdC region has been performed. To test the expression of the gene, a lacZ-Km cartridge was introduced into the gene. By this construct, tryptophan-dependent stimulation of gene expression in A. brasilense Sp7 was observed. Evidences for the existence of another copy of the ipdC gene in the Azospirillum genome are also reported.

Reduction in goiter size by 131I therapy in patients with non-toxic multinodular goiter.

A retrospective follow-up study of 131I treatment was performed in 10 females (median age 48 years, range 40-74 years) with non-toxic multinodular goiter. The median dose of 131I given was 20 mCi (range 14-65 mCi). Thyroid volume was measured by ultrasonography. The median follow-up period was 26 months (range 12-68 months). Nine patients had a reduction of goiter size: thyroid volume decreased from 88 +/- 14.9 ml (mean +/- SEM) to 49 +/- 10.9 ml 1 year after 131I treatment. The relative decrease of goiter size was 48% after 1 year (N = 9) and 59% after 2 years (N = 5). One patient did not respond and was referred for operation. Side effects were mild spontaneously resolving radiation thyroiditis in one patient and subclinical hypothroidism in four patients. In conclusion, 131I treatment of non-toxic goiter is an effective treatment at the expense of post-radiation (subclinical) hypothyroidism.

The clinical importance of routine measurement of liver enzymes, total protein and albumin in a general medicine outpatient clinic: a prospective study.

UNLABELLED: The objective was to study the usefulness of routine measurement of liver enzymes (ASAT, ALAT, alkaline phosphatase, gamma-GT), and total protein (TP) and albumin (Alb) in a general medicine outpatient clinic. A prospective study was made of consecutive patients who were classified according to whether or not an indication for the tests was present. All six tests were measured in all patients. Physicians were kept unaware of the results of tests in patients with no indication for ordering the test. The setting was a general internal medicine outpatient clinic in a 850-bed teaching hospital which serves as a referral clinic for general practitioners. There were 615 consecutive patients who were all new referrals to the outpatient clinic. The results of all patients with no indication for the test but who had abnormal results were presented to a panel of three experienced internists who decided whether the results had any clinical importance. Repeat measurements of the tests or follow-up results were obtained in all these patients. Seventy-eight of 320 patients in whom no indication for the test for liver enzymes existed had abnormal results. In only six of these (1.9%) were the abnormalities of clinical significance. In 56 of 449 patients in whom no indications were present for TP and Alb measurement the results were abnormal. In only 2 (0.4%) was this clinically important. CONCLUSION: the routine measurement of these six tests in general medicine outpatient clinics should be abandoned because of the low yield.