Fixed 30 mCi (1110 MBq) 131I-iodine therapy in autonomously functioning nodules: Single toxic nodule as a predictive factor of success

Aims:

The aim of this study is to evaluate the efficacy of a fixed 30 mCi (1110 MBq) ¹³¹I-iodine dose for the treatment of hyperthyroidism due to uninodular or multinodular toxic goiter and identify predictors of success.

Materials and Methods:

Fifty-nine patients diagnosed with nonautoimmune toxic goiter were treated with a fixed 30 mCi dose of ¹³¹I-iodine and were followed at a tertiary service between 2000 and 2016. The therapy was considered successful if the patient reached euthyroidism or hypothyroidism without needing an extra ¹³¹I-iodine dose or antithyroid drugs for at least 1 year after the radioiodine therapy (RIT).

Results:

Patients with a single toxic nodule were younger at diagnosis (52 vs. 63 years; P = 0.007), presented a shorter disease duration until RIT (2 vs. 3.5 years; P = 0.007), smaller total thyroid volume (20 vs. 82 cm³; P = 0.044), and lower pre-RIT thyroid uptake (P = 0.043) than patients with multinodular goiter. No significant difference was seen with antithyroid drug use, thyroid-stimulating hormone and free thyroxine level, and follow-up after RIT. After RIT, 47 patients (79.66%) met the success criteria, and 12 (20.33%) remained hyperthyroid. Among the success group, 32 (68.08%) reached euthyroidism, while 31.92% developed hypothyroidism after 1 year. Patients with single toxic nodules who achieved success after RIT presented smaller nodules (2.8 vs. 5.75 cm; P = 0.043), while the pre-RIT thyroid uptake was higher among patients with multinodular toxic goiter who achieved success after RIT (5.5% vs. 1.5%; P = 0.007). A higher success rate was observed among patients with a single toxic nodule than those with a toxic multinodular goiter (92.3% vs. 55%; P = 0.001), and a single toxic nodule presentation was found to be an independent predictor of success (P = 0.009).

Conclusions:

The fixed 30 mCi ¹³¹I-iodine dose was particularly effective in the group of patients with single autonomously functioning nodule rather than the group with multiple nodules. A single toxic nodule was an independent predictor of treatment success.

The relationship between quality of life, cognition, and thyroid status in Graves' disease

PURPOSE

To assess quality of life (QoL) and cognitive function among Graves' disease (GD) patients with different thyroid status, with and without ophthalmopathy.

METHODS

This is a cross-sectional clinic-based study involving 154 patients with GD (81.27% were female, mean age 45.6 ± SD 11.2 years) and 54 (35.06%) had ophthalmopathy. Data were collected after an informed consent from all patients was obtained. All patients completed the 36-Item Short Form Health Survey and Mini-Mental State Examination. Patients with ophthalmopathy also completed the Graves' Orbitopathy Quality of Life Questionnaire.

RESULTS

Patients with hyperthyroidism presented a greater impairment in QoL when compared to euthyroidism group. A lower score in physical role functioning was found in both subgroups with active disease (hyperthyroidism and euthyroidism using thionamides). A lower score was also seen in visual function, only in patients with hyperthyroidism, without difference in appearance. No difference was found in cognition between patients. Younger ages at diagnosis, male sex, euthyroidism and absence of ophthalmopathy were factors associated with better QoL, as well as a shorter disease duration was associated with better recall, attention and calculation.

CONCLUSIONS

An impairment in QoL among patients with active GD was evidenced, even in those receiving thionamides and in euthyroidism. Ophthalmopathy was a factor associated with a poor QoL and no clear evidence of cognitive impairment was demonstrated.

Vitamin D in Hashimoto's thyroiditis and its relationship with thyroid function and inflammatory status

Several studies have shown the correlation between vitamin D [25(OH)D] deficiency and thyroid autoimmunity and reducing of thyroid autoantibodies in patients with normal levels of vitamin D combining with thyroid hormone replacement. However, other authors not agree with this association. It is still unclear whether the low 25(OH)D levels are the result of HT disease or a part of its cause. We studied 88 patients with HT regarding vitamin D status and thyroid autoimmunity markers as well as the relationship with cytokines produced by Th1, Th2, and Th17 cells compared with a control group of 71 euthyroid healthy subjects. The present study demonstrated that vitamin D concentrations were similar in patients HT and the control group. The reduction of free T4 levels was a predictor of vitamin D insufficiency for Hashimoto's thyroiditis, but not for the control group. Lower concentrations of TNF-α was a predictor of lower levels of vitamin D. Differences in the association between HT and vitamin D insufficiency remain unresolved in the literature. The thyroid hormone status would play a role in the maintenance of vitamin D sufficiency, and its immunomodulatory role would influence the presence of autoimmune thyroid disease. The positive correlation between free T4 and vitamin D concentrations suggests that adequate levothyroxine replacement in HT would be an essential factor in maintaining vitamin D at sufficient levels.

Barriers to insulin initiation in elderly patients with type 2 diabetes mellitus in Brazil

AIMS

We aimed to explore insulin initiation barriers in the Brazilian Type 2 Diabetes Mellitus (T2DM) elderly population, according to the physician's perspective, and suggest strategies to overcome them.

METHODS

A 45-questions survey addressing issues as clinical characteristics, barriers to insulinization, and treatment strategies in elderly patients with T2DM, was sent to six endocrinologists from different Brazilian locations. Thereafter, all the respondents participated in a panel discussion to validate their responses and collect additional relevant data.

RESULTS

Endocrinologists had at least 15 years of experience, with a mean of 63 elderly patients per month. Nearly 25% of the elderly patients were treated in the Brazilian public healthcare system (SUS, Unified Health System); only a quarter presented proper glycemic control. In contrast, 55% of the patients from private healthcare system presented adequate glycemic control. The main barriers for insulin initiation for patients, according to physicians' perspective, are side effects and negative perception over treatment (100%). For endocrinologists, main barriers were lack of time to guide patients and concern over side effects (83%). Therefore, specialists considered education for both healthcare professionals and patients as one of the most important strategies to circumvent the current scenario related insulin therapy among elderly patients in the country.

CONCLUSION

Insulin therapy remains underused due to several barriers, such as concern over side effects and negative perception. Educational measures for patients and HCPs could improve the current scenario.

Value of Apoptotic, Antiapoptotic, and Cell Proliferation Markers in the Treatment of Graves' Disease

To better understand the genesis of autoimmunity in Graves' disease (GD), it is essential to study the mechanism of apoptosis and cell proliferation in thyroid cells and intrathyroidal lymphocytic infiltrate of GD patients. Methods. A cross sectional, observational study performed by evaluating histopathological samples of thyroidectomy products from GD patients using immunohistochemistry. New histological sections were prepared for immunohistochemical analysis with markers of cell proliferation, antiproliferation, apoptosis, and antiapoptosis. Results. Patients with GD who underwent radioiodine therapy (RIT) had a lower lymphocytic expression level of p27Kip1, and those who took beta-blockers had higher expression levels of BID (BH3-interacting domain) and a lower Ki-67 expression level in thyrocytes than those who did not. The association of a shorter diagnostic time with a lower expression level of MCL-1 in thyroid cells suggests that the hyperthyroid state was related to a lower antiapoptotic effect on thyrocytes. In comparison to patients with GD not using antithyroid drugs (ATD), we found a lower expression level of BID in lymphocytes for those who used ATD. Conclusion. In GD, the hyperthyroid state was associated with a lower antiapoptotic effect on thyroid cells. RIT, beta-blockers, and thionamide act by stimulating apoptosis of thyrocytes by intrathyroidal lymphocytes.

Relationship of thyroid hormone levels and cardiovascular events in patients with type 2 diabetes

Alterations in thyroid hormone levels are found associated with inflammation in patients with non-thyroidal illness (NTIS) and are common in patients with type 2 diabetes mellitus (T2DM). Inflammation has also been linked with development of cardiovascular events (CVE) in T2DM. Our objective was to assess whether thyroid hormone abnormalities typical of NTIS in patients with T2DM are related to inflammation and CVE. This was a cross-sectional study of 140 subjects; 70 with T2DM and 70 as a control group paired by age, sex and body mass index (BMI). We recorded age, sex, BMI, waist/hip ratio, diabetes duration, HbA1c, CVE history, serum amyloid A (SAA), TSH, total (T) and free (F) T4 and T3, reverse T3 (rT3) and TT3/rT3 ratio. Patients with T2DM had lower levels of TT4 (p = 0.012), TT3 (p < 0.001), FT3 (p < 0.001) and TT3/rT3 (p = 0.002). They also showed higher FT4 (p < 0.001) and similar TSH levels (p = 0.627) compared to the control group. SAA levels correlated positively with rT3 (r = 0.45; p < 0.001) and inversely with TT3/rT3 (r = -0.38; p = 0.001). Patients with T2DM and history of CVE had higher rT3 (p = 0.006) and lower TT3/rT3 (p = 0.002), along with higher SAA levels (p = 0.002) than patients without this characteristic. Multiple logistic regression showed that factors independently associated with CVE were older age (OR = 1.159, 95 % CI 1.011-1.329), male sex (OR = 4.391, 95 % CI 1.081-17.829) and higher TT3/rT3 (OR = 0.993, 95 % CI 0.987-0.999). We have confirmed the presence of NTIS in T2DM. We also showed that thyroid hormone abnormalities are associated to inflammatory activity and to CVE in these patients.

Evidence-based clinical use of insulin premixtures

Brazil is expected to have 19.6 million patients with diabetes by the year 2030. A key concept in the treatment of type 2 diabetes mellitus (T2DM) is establishing individualized glycemic goals based on each patient's clinical characteristics, which impact the choice of antihyperglycemic therapy. Targets for glycemic control, including fasting blood glucose, postprandial blood glucose, and glycated hemoglobin (A1C), are often not reached solely with antihyperglycemic therapy, and insulin therapy is often required. Basal insulin is considered an initial strategy; however, premixed insulins are convenient and are equally or more effective, especially for patients who require both basal and prandial control but desire a more simplified strategy involving fewer daily injections than a basal-bolus regimen. Most physicians are reluctant to transition patients to insulin treatment due to inappropriate assumptions and insufficient information. We conducted a nonsystematic review in PubMed and identified the most relevant and recently published articles that compared the use of premixed insulin versus basal insulin analogues used alone or in combination with rapid-acting insulin analogues before meals in patients with T2DM. These studies suggest that premixed insulin analogues are equally or more effective in reducing A1C compared to basal insulin analogues alone in spite of the small increase in the risk of nonsevere hypoglycemic events and nonclinically significant weight gain. Premixed insulin analogues can be used in insulin-naïve patients, in patients already on basal insulin therapy, and those using basal-bolus therapy who are noncompliant with blood glucose self-monitoring and titration of multiple insulin doses. We additionally provide practical aspects related to titration for the specific premixed insulin analogue formulations commercially available in Brazil.

Atherogenic lipid profile of Brazilian near-term newborns

Cardiovascular disease is the primary cause of death in Brazil. Recent studies have shown that low birth weight and preterm birth are linked to a higher prevalence of cardiovascular disease. The aim of the present study was to compare the levels of lipids and apolipoproteins and atherogenic indexes between term and near-term newborn infants. A sample of umbilical cord blood was obtained from 135 newborns (66 males) divided into two groups: 25 near-term neonates (35-36.6 weeks of gestational age) and 110 term neonates (37-42 weeks of gestational age). The total cholesterol concentrations were higher in the near-term neonates than in the term group (94.04 +/- 8.02 vs 70.42 +/- 1.63 mg/dl, P < 0.01), due to an increase in the LDL-cholesterol fraction in the near-term group (57.76 +/- 6.39 vs 34.38 +/- 1.29 mg/dl, P < 0.001). The atherogenic indexes (total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol and apolipoprotein B/apolipoprotein A-I) were higher in the near-term group (P < 0.001, P < 0.001, and P < 0.05, respectively). The gestational age of the newborns was inversely correlated with total cholesterol and LDL-cholesterol, and also with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol indexes. These findings demonstrate that the lipid profile is worse in the group of near-term neonates compared with the term group. Future studies are needed to determine if this atherogenic profile in near-term neonates can affect body metabolism, increasing the risk for cardiovascular diseases in adult life.

Inverse relationship between cord blood adiponectin concentrations and the number of cigarettes smoked during pregnancy

BACKGROUND

Maternal smoking is linked with several neonatal metabolic disorders. Adiponectin is an adipose-specific hormone with anti-inflammatory and antiatherogenic properties.

AIM

The aim of this study was to evaluate the effect of maternal smoking on cord blood adiponectin concentrations.

METHODS

We evaluate the effect of maternal smoking on cord blood adiponectin concentrations comparing 14 full-term and seven preterm newborns born to mothers who smoked during pregnancy with 77 full-term and 10 preterm neonates born to non-smokers mothers.

RESULTS

Maternal smoking during pregnancy was significantly associated with decreased adiponectin levels of preterm newborns (p < 0.05).

CONCLUSIONS

Our findings also reveal a significant relationship between the reported number of cigarettes smoked during pregnancy and cord blood adiponectin concentrations (p = 0.01), suggesting that this association could have a causal relationship.

99mTc-sestamibi thyroid uptake in euthyroid individuals and in patients with autoimmune thyroid disease

PURPOSE

We investigated the biokinetics of (99m)Tc-sestamibi in the thyroid of euthyroid volunteers (EVs) and in patients with autoimmune thyroid diseases and determined the best time interval between (99m)Tc-sestamibi injection and calculation of uptake.

METHODS

Forty EVs, 30 patients with Graves' disease (GD), 15 patients with atrophic Hashimoto's thyroiditis (AHT) and 15 patients with hypertrophic Hashimoto's thyroiditis (HHT) underwent (99m)Tc-sestamibi thyroid scintigraphy. Dynamic images were acquired for 20 min, and static images were obtained 20 min, 60 min and 120 min post injection. Five-, 20-, 60- and 120-min uptake, time to maximal uptake (T(max)) and T(1/2) of tracer clearance were calculated. Thyroid hormones and antibodies were measured. (99m)Tc-pertechnetate uptake was investigated in GD patients.

RESULTS

T(max) was approximately 5 min in all four groups. The mean T(1/2) value for EVs was similar to the GD value and lower than the HHT and AHT values. The mean (+/-SD) 5-min uptake was 0.13% (+/-0.05%) for EVs. The 5-min uptake in GD was higher than that in EVs(P<0.001) and correlated with free thyroxine (r=0.54) and with (99m)Tc-pertechnetate uptake (r=0.68). Uptake in HHT was higher than that in AHT (P=0.0003) and EVs (P=0.002). Uptake in AHT was lower than uptake in EVs (P=0.0001).

CONCLUSION

Five minutes is the optimal time interval between (99m)Tc-sestamibi injection and calculation of thyroid uptake. Five-minute uptake differentiates euthyroid individuals from GD patients. There is a high correlation between (99m)Tc-sestamibi and (99m)Tc-pertechnetate uptake in GD. The reduced (99m)Tc-sestamibi uptake in AHT patients is probably due to glandular destruction and fibrosis. Inflammatory infiltrate and high mitochondrial density in thyrocytes possibly explain the increased uptake in GD and HHT.

Does maternal smoking influence leptin levels in term, appropriate-for-gestational-age newborns?

OBJECTIVES

Leptin, a hormone produced in adipose tissue and the placenta, is correlated with neonatal growth. The aim of this study was to investigate the effect of maternal smoking during pregnancy on cord blood leptin concentrations in term, appropriate-for-gestational-age infants.

METHODS

Two groups of term, appropriate-for-gestational-age newborns were selected: 19 infants of smoking mothers and 91 infants of non-smoking mothers. Neonatal anthropometric measurements were taken and leptin levels were measured by radioimmunoassay.

RESULTS

Leptin concentrations were similar (p=0.915) between the groups. Leptin levels correlated only with ponderal index (p < 0.01) and gestational age of the newborns (p < 0.05).

CONCLUSIONS

This study indicates that maternal smoking during pregnancy does not affect cord blood leptin levels in term, appropriate-for-gestational-age infants.

HLA-DRB1*04 and HLA-DQB1*03 association with the atrophic but not with the goitrous form of chronic autoimmune thyroiditis in a Brazilian population

Autoimmune chronic lymphocytic thyroiditis appears in two forms, goitrous and atrophic. The evidence available is not enough to prove that the goitrous precedes the atrophic form, but immunogenetic analysis suggests that they may be distinct entities. The distribution of HLA class II alleles DRB1* and DQB1* was verified in patients from the region of Campinas, São Paulo, Brazil with both forms of thyroiditis. Ninety-one patients with primary hypothyroidism through autoimmune thyroiditis were classified as goitrous - 54 patients, 42.27 +/- 11.72 years old, having had hypothyroidism for 8.57 +/- 6.63 years - or atrophic - 37 patients, 42.72 +/- 12.01 years old, hypothyroidism for 6.73 +/- 4.07 years. The distribution of class II alleles was determined, DRB1* and DQB1* were genotyped after purifying DNA blood samples using the DNAzol technique, and the low-resolution PCR-SSP system was utilized for determination of generic alleles. Chi-square and Fisher's exact test were utilized to compare the distribution frequency of HLA alleles and the significant p-values were subjected to Bonferroni correction. We have demonstrated that the DRB1*04 allele is associated with autoimmune thyroiditis, and that there are genotypic differences regarding the presentation forms with a strong association between DRB1*04 and DQB1*03 and the atrophic form only.

Sibutramine enhances insulin sensitivity ameliorating metabolic parameters in a double-blind, randomized, placebo-controlled trial

AIM

To assess the effect of sibutramine-assisted weight reduction program on insulin sensitivity and metabolic parameters in obese normal glucose tolerant individuals over a period of 24 weeks.

RESEARCH DESIGN AND METHODS

A double-blind, placebo-controlled, parallel, prospective clinical trial was carried out at our medical centre. Forty female normal glucose tolerant patients, body mass index: 34.3 +/- 2.9 kg/m2 and age: 41.1 +/- 9.9 (range: 19-58 years), were randomized to placebo or sibutramine, 10 mg once daily.

RESULTS

Seventeen patients from sibutramine group and 14 placebo had completed the study protocol. Significant weight change was seen in sibutramine (p < 0.01) (-5.6 kg or -6.1% vs. +0.9 kg or +1.1% in placebo). Insulin sensitivity enhanced in sibutramine group (Kitt: from 4.03 +/- 1.97 to 5.09 +/- 2.48%/min; p < 0.05). Homeostasis model assessment-IR (HOMA-IR) decreased from 7.8 +/- 6.9 to 5.6 +/- 4.5 (p < 0.05). HOMA-beta also decreased from 508 +/- 381 to 374 +/- 256 (p < 0.05). No changes were observed in the placebo control group regarding insulin sensitivity or secretion. Concomitant reductions were observed in the sibutramine group in lipid parameters (triglycerides and high-density lipoprotein-cholesterol), uric acid and gamma-glutamyl transferase (p < 0.05).

CONCLUSIONS

Sibutramine has demonstrated efficacy in reducing weight in non-diabetic women along with amelioration in insulin sensitivity and additional improvement in metabolic parameters.

The insulin tolerance test in morbidly obese patients undergoing bariatric surgery

OBJECTIVE

To assess the effect of massive weight loss in relation to insulin resistance and its correlation to changes in glycemic homeostasis and lipid profile in severely obese patients.

RESEARCH METHODS AND PROCEDURES

A prospective clinical intervention study was carried out with 31 morbidly obese women (body mass index: 54.2 +/- 8.8 kg/m(2)) divided into three groups according to their glucose tolerance test: 14 normal, 8 impaired glucose tolerance, and 9 type 2 diabetes. All subjects underwent an insulin tolerance test with intravenous bolus of 0.1 U insulin/kg body weight before silastic ring vertical gastroplasty Roux-en-Y gastric bypass surgery, and again at 2, 4, 6, and 12 months postoperatively. Fasting plasma glucose, hemoglobin A1c, and lipid profile were also evaluated.

RESULTS

A reduction of 68 +/- 15% in initial excess body weight was evident within 1 year. Along with weight loss, the following statistically significant changes were found: an increase in the insulin-sensitivity index (Kitt) and a decrease in fasting plasma glucose and hemoglobin A1c, most notably in the type 2 diabetes group. An overall improvement in lipid profile was observed in all three groups.

DISCUSSION

Bariatric surgery was an effective therapeutic approach for these obese patients because it reduced both weight and insulin resistance, along with improving metabolic parameters. Significant correlations were found between insulin resistance and metabolic improvements. Weight loss after bariatric surgery induced an improvement in metabolic fitness, related to the reduction in insulin resistance over a range of glucose tolerance statuses from normal to diabetic.

Serum leptin levels after bariatric surgery across a range of glucose tolerance from normal to diabetes

BACKGROUND

A longitudinal, clinical intervention study with bariatric surgery was done to investigate the relationship between leptin levels, BMI, and insulin during weight loss across a range of glucose tolerance from normal to diabetes.

METHODS

43 morbidly obese patients (BMI: 42-75 kg/m2) undergoing vertical banded gastroplasty Roux-en-Y gastric bypass (VBG-RGB), were divided into 3 groups: 21 normal (NGT), 12 impaired glucose tolerance (IGT) and 10 type 2 diabetes (DM). Leptin, insulin, glucose, lipids and uric acid were measured at baseline and 2, 4, 6, and 12 months following surgery.

RESULTS

BMI fell from 54.1 +/- 9.1 to 34.6 +/- 6.3 kg/m2, similarly in all groups. Leptin decreased from 73.9 +/- 8.7 to 16.9 +/- 10.2 ng/ml and was strongly correlated with BMI during 1-year follow-up (r = 0.78; p < 0.001). Linear univariate analysis for repeated evaluation showed a positive correlation between leptin and glucose, triglycerides, uric acid, and insulin. Multivariate regression analysis indicated that BMI was independently correlated with the decrease in leptin (p < 0.001), accounting for 66% of the variance in leptin levels during weight loss. These results were found in the NGT and IGT groups. In the DM group, a small additional influence in leptin levels was attributed to glucose decrease.

CONCLUSIONS

A strong link between leptin and BMI was found after surgery. BMI was the main determinant of the decrease of leptin. In these patients submitted to bariatric surgery, ranging from normal glucose tolerance to diabetes, changes in insulin levels and metabolic parameters, except for glucose in the DM group, did not appear to be correlated with changes in leptin levels.

Antithyroid drugs inhibit in vivo HLA-DR expression in thyroid follicular cells in Graves' disease

Antithyroid drugs have been reported to reduce the expression of HLA-DR in thyrocytes in Graves' disease, but only circumstantial evidence has been provided about their in vivo immunologic effects. This present study was designed to examine the in vivo immunologic effect of antithyroid drugs on thyroid follicular cells. The study was conducted on 25 patients who had Graves' disease in remission or in activity and who were or were not receiving treatment (7 in overt thyrotoxicosis, 6 patients in remission, and 12 patients under medication). HLA-DR expression in thyroid biopsies was verified by immunohistochemistry. The follicular cells of all patients in overt thyrotoxicosis expressed HLA-DR whereas those of patients in remission were negative for HLA-DR. HLA-DR was also not expressed in all patients under medication, but this did not correlate with the clinical evolution after thyroid drug withdrawal. In conclusion, antithyroid drugs inhibit follicular cell HLA-DR expression in Graves' disease, when thyrotoxicosis is controlled. This suggests that additional mechanisms not involving HLA-DR play a role in thyroid autoimmune disease.

Thyroid suppression test with L-thyroxine and [99mTc] pertechnetate

OBJECTIVE

The thyroid suppression test is still used in some centres as an adjunt in the diagnosis of autonomous functioning thyroid nodules. With the purpose of minimizing the disadvantages of the original T3 suppression test, we have evaluated the efficacy of a method using L-thyroxine as TSH suppression agent and [99 mTc] pertechnetate as radiopharmaceutical.

DESIGN

Open nonrandomized prospective study

MATERIALS AND METHODS

A control group of 15 normal volunteers (11 males, 4 females; 21-35 years, mean 26.4 years) and a patient group of 20 patients (18 females, 2 males; 27-83 years, mean 53.6 years) divided into 4 subgroups, were studied: 7 patients with autonomous functioning nontoxic nodules, 3 with autonomous functioning toxic nodules, 7 with Graves disease and 3 with nonautoimmune diffuse toxic goitre. Baseline thyroid uptake and imaging were begun 20 minutes after an intravenous injection of 370 MBq (10 mCi) of [99 mTc] pertechnetate. This was followed by a single daily intake of 2 microg/kg of L-thyroxine, for 10 days. Thyroid imaging and uptake were then repeated.

RESULTS

In the control group [99 mTc] pertechnetate uptake after L-thyroxine suppression had a mean reduction of 75.8 +/- 7.69% (58-87%) in comparison to the baseline level. All subjects were euthyroid by clinical and laboratory criteria and none complained of side-effects, despite significant suppression of TSH levels. In the patient group, thyroid uptake after suppression decreased in 10 patients (maximum reduction 39%), was unchanged in 2 patients and increased in the remaining 8 patients.

CONCLUSION

The method described was efficient for demonstration of autonomous thyroid tissue, since none of the patients showed significant reduction of thyroid uptake after L-thyroxine suppression compared with the control group. This test was as effective as the original T3 suppression test, but more convenient to the patient: no side-effects, ease of hormonal intake, low dosimetry and short stay in the nuclear medicine laboratory.

Relationship between HLA antigens and infectious agents in contributing towards the development of Graves' disease

Graves' disease (GD) is an autoimmune thyroid disorder which is associated with the human leucocyte antigens HLA-DR3 and DQA1* O501 in Caucasians. We have explored the possibility that some patients with certain HLA specificities develop anti-HLA antibodies which are correlated with environmental factors that may contribute to the development of GD. We studied 40 GD patients and 157 healthy individuals (controls). Serology was used to type HLA-A, -B, -Cw, and -DR antigens. The frequencies of these antigens in relation to lymphocytotoxic anti-HLA-A-B-Cw-DR antibodies and two environmental factors (Yersinia enterocolitica and Coxsackie B virus) were determined. The frequencies of HLA-B15, -B21 and DR3 antigens were increased, whereas HLA-DR5 antigen was decreased in GD patients. A significant association between HLA-DR3 antigen and lymphocytotoxic antibodies was observed, i.e., IgGs from GD patients were cytotoxic to HLA-DR3+ normal B cells. Following absorption with Yersinia enterocolitica or Coxsackie-B-virus, only Coxsackie-B virus completely inhibited the lymphocytotoxic reactions against HLA-DR3+ B cells. Besides confirming the association of HLA-DR3 with GD, this study also suggests the role of Coxsackie-reactive HLA-DR3 antibodies as contributing factors to the pathogenesis of the disease.

Total body zinc depletion and its relationship to the development of hyperprolactinemia in chronic renal insufficiency

Modulation of free plasma zinc levels has been implicated in the increase in plasma prolactin levels seen in patients with chronic renal insufficiency (CRI). The relative importance of this mechanism in comparison to others, however, has not been elucidated. Zinc equilibrium between plasma and red blood cells is partly dependent upon red blood cell carbonic anhydrase (CA). In the present paper, we have investigated the interrelationships among total plasma zinc, leukocyte zinc, prolactin, and erythrocyte CA in patients with CRI. Uremic patients were shown to have significantly increased levels of plasma prolactin and erythrocyte CA activity when compared to normal controls. Moreover, red blood cell CA total concentration and isoenzyme-I and-II levels, as well as plasma zinc were found to be significantly decreased in uremic patients in comparison to normal controls. In patients with CRI, a negative correlation was demonstrated between erythrocyte CA catalytic activity and plasma zinc, as well as between plasma zinc and plasma prolactin levels. Moreover, leukocyte zinc content, which is a reliable indicator of total body zinc stores, was found to be significantly decreased in uremic patients when compared to normal controls. A strong negative correlation between leukocyte zinc content and plasma prolactin levels was documented in CRI patients. Our results suggest that alterations in erythrocyte CA levels, enzymatic activity or isoenzyme profile are most probably mechanistically and etiologically unrelated to the high plasma prolactin levels in CRI patients. Contrariwise, depletion of total body zinc stores, rather than redistribution of this trace metal among extracellular compartments, may represent one of the major contributing mechanisms leading to uremic hyperprolactinemia.

Periodic remission in Cushing's disease with paradoxical dexamethasone response: an expression of periodic hormonogenesis

A patient with Cushing's disease due to a chromophobe adenoma was studied for 243 days before pituitary surgery and evidence for periodicity in cortisol steroid production was found with cycles occurring every 85.8 days (peak-to-peak length), associated with laboratory remissions and paradoxical response to dexamethasone. The autonomy of ACTH secretion was suggested by the nonresponsiveness to repeated lysine-vasopressin stimulation tests and lack of increase in urinary 170HCS following metyrapone. A distinct response of the hyperplastic glands (as demonstrated by percutaneous adrenal venography) was obtained on several B1-24 corticotropin stimulation. The patient's hypercortisolism disappeared following removal of the chromophobe adenoma through transphenoidal hypophysectomy.