Antonis Polymeris

Heterophilic antibodies causing falsely high serum calcitonin values

Heterophilic antibodies (HA) may interfere in some immunoassays, causing falsely high hormone values, of wich practitioners should be aware when measuring calcitonin (CT) used as tumor marker for medullary thyroid carcinoma (MTC). We studied four patients with thyroid nodules, three of whom underwent surgical neck exploration, after an erroneous diagnosis of MTC because of falsely high serum CT eventually proved to be due to HA. One patient had a lingual thyroid, two autoimmune thyroiditis and the fourth a colloid goiter. The minimal incremental CT response to calcium infusion raised our suspicion of possible false high CT values due to HA. There was no linearity of the CT values obtained by testing serial dilutions of the sera in the CT assay, which employs two monoclonal mouse anti-CT antibodies. Addition of normal mouse gamma globulin eliminated the interference by HA in the sera of two patients. Serum assayed in a polyclonal radioimmunoassay using goat anti-CT antibodies gave normal CT values. Finally, incubation of the sera in Heterophilic Blocking Tubes® (HBT) eliminated the false CT immunoreactivity. A spontaneous change of the CT serum concentrations was noticed in three patients over several months, apparently due to changing titles of HA. We suggest that, in patients a) whose CT response to calcium or pentagastrin infusion is minimal despite high basal CT values, b) with autoimmune thyroiditis and c) in whom an unexpected change in serum CT concentrations occurs, the possibility of spuriously high CT values because of circulating HA should be considered.

Effect of an Oral Glucose Load on PTH, 250HD3, Calcium, and Phosphorus Homeostasis in Postmenopausal Women

Introduction. Previous studies particularly in children and neonates have shown that serum calcium declines and parathyroid hormone (PTH) rises during an oral glucose load. However, there is not a general agreement in this regard. This study was carried out to evaluate the effects of an oral glucose load on calcium and phosphorus homeostasis in postmenopausal women along with serum insulin, PTH, and 250HD3 changes. Patients and methods. After an overnight fasting, an oral glucose tolerance test was performed in 50 postmenopausal women; and glucose, insulin, PTH, and D3 were measured at baseline and every 30 min during the 2 hours of the test. Results. Serum glucose and insulin increased as expected and reached their peak values at 60 and 90 min, respectively. PTH and phosphorus decreased significantly and the maximum decline was observed at 30 and 120 min after glucose load (p < 0.0001), respectively. Serum calcium, magnesium, and D3 levels showed no significant changes at any time measured. Serum PTH values had a significant negative correlation with glucose and insulin values (p = 0.026 and p = 0.031, respectively). Serum D3 also correlated negatively with glucose (p = 0.002). Conclusion. Our study shows that an oral glucose load induced hyperglycemia/hyperinsulinemia promotes a significant decline in serum PTH and phosphorus levels without changes in calcium or 250HD3 in postmenopausal women.

Changes in risk factors and Tumor Node Metastasis stage of sporadic medullary thyroid carcinoma over 41 years, before and after the routine measurements of serum calcitonin

The measurement of serum calcitonin (CT) in all thyroid nodules for the detection of medullary thyroid carcinoma (MTC) is controversial. We compare several prognostic factors, Tumor Node Metastasis (TNM) stage, and survival in sporadic MTC patients operated on before and after the use of routine measurements of serum CT in combination with thyroid ultrasonography (US). Thirty-seven patients had been operated on between 1969 and 1989 (group I), before the use of routine measurements of serum CT and the routine use of thyroid US, and 39 (group II) had been operated on between 1990 and 2009, after the introduction of routine use of serum CT and thyroid US. There were no between-group differences concerning age and sex. Group I had larger tumors at the time of operation (P < .001) and higher postoperative serum CT levels (P < .001). Cervical lymph node and distant metastases were found more frequently in group I in comparison with group II. The cases with TNM stage I were significantly higher in group II than in group I, in contrast with the cases with TNM stage IV that were significantly higher in group I. Univariate analysis revealed a significantly higher 15-year survival rate in group II than in group I (P = .002). The postoperative CT levels were positively correlated with tumor size (P < .001). During the last 2 decades, the diagnosis of sporadic MTC at an earlier stage has been made possible by the routine use of serum CT in combination with thyroid US. The significant increase of the 15-year survival rate shows better outcome in these patients.

Bone mineral density and bone metabolism in hemodialysis patients: Correlation with PTH, 25OHD3 and leptin

BACKGROUND Bone metabolism disorders in hemodialysed patients (HD) involve several humoral factors, of which PTH plays the central role. Leptin is usually found increased in renal failure and its link with bone metabolism has not been elucidated. We investigated the BMD and bone metabolism in association with serum PTH, 25OHD3 and leptin in HD patients. METHODS We measured bone alkaline phosphatase (bSAP), cross linked N telopeptide of type 1 collagen (NTx), PTH, 25OHD3 and leptin in 37 HD patients. We also evaluated BMI and BMD in lumbar spine (LS) and in femoral neck (FN) by DXA. Statistical evaluations were based on simple regression analysis. RESULTS 1) Osteopenia was found in 32,1% in LS and 50% in FN and osteoporosis in 14.3% and 21.4% of our patients, respectively. LS or FN Z score was not related to HD duration. 2) Bone markers, PTH, phosphorus and leptin levels were increased. 3) 25OHD3 was low and was not related to NTx, bSAP or PTH. 4) PTH correlated with bone markers and Z score in LS and FN. 5) Leptin had no correlation with bone markers or Z score (except BMI). CONCLUSIONS In our hemodialysed patients bone metabolism markers were increased in relation with high serum PTH levels. The observed high serum leptin was not associated with bone metabolism. Additionally the duration of hemodialysis did not appear to affect bone density.

The pluses and minuses of bariatric surgery for morbid obesity: An endocrinological perspective.

Obesity both in adults and children has emerged as a worldwide epidemic. Obesity is associated with an increased risk of a number of comorbidities including type 2 diabetes mellitus, hypertension, dyslipidemia, obstructive sleep apnea, certain types of cancer, degenerative joint disease, non-alcoholic fatty liver disease, reflux esophagitis, stroke, coronary heart disease, venous stasis ulcers, cholelithiasis, erectile dysfunction and polycystic ovary syndrome. It is now generally accepted that bariatric surgery procedures induce long-term weight loss and offer resolution or dramatic improvement in numerous comorbidities of obesity, including type 2 diabetes mellitus, hypertension and dyslipidemia. These effects mainly arise from endocrine changes resulting from the gastrointestinal surgical procedures. The aim of this short review was to evaluate the pros and cons of bariatric surgery for morbid obesity seen from the perspective of a practicing endocrinologist.

An Average Body Circumference Can Be a Substitute for Body Mass Index in Women

Introduction. Significant correlations between BMI and some body circumferences have been previously reported. In this study we investigated if the average of the sum of eight body circumferences can be a substitute for BMI. Patients and Methods. BMI and eight body circumferences (neck, waist, hip, arm, forearm, wrist, thigh, and ankle) were measured in 193 apparently healthy women aged 20–83, and within a wide range of BMI. Women with BMI ≤ 24.9 were designated as normal, with BMI 25–29.9 as overweight and with BMI ≥ 30 as obese. The relationship of the average body circumference (ABC) of the sum of the eight circumferences, and of each individual circumference with BMI, was evaluated. Results. ABC had the strongest correlation with BMI (r = 0.95, P < 0.001) among all the circumferences tested. Hip circumference had the strongest correlation with BMI (r = 0.89, P < 0.001) among the circumferences of individual body sites. Receiver-Operator Characteristic analysis showed that women with ABC > 44.0 cm could be recognized as having BMI ≥ 25 with sensitivity 90.2% and specificity 88.5%, while women with ABC > 47.1 cm could be diagnosed as having BMI ≥ 30 with sensitivity 92.2% and specificity 91.5%. Conclusion. An average body circumference strongly correlated with BMI in women and can serve as a surrogate of BMI.