Thyroidal effect of metformin treatment in patients with polycystic ovary syndrome.

OBJECTIVE: Metformin is widely used for the treatment of type 2 diabetes. Growing evidence supports the beneficial effects of metformin also in patients with polycystic ovary syndrome (PCOS). It was recently reported that metformin has a TSH-lowering effect in hypothyroid patients with diabetes being treated with metformin. DESIGN: Aim of this study was to evaluate the effect of metformin treatment on the thyroid hormone profile in patients with PCOS. PATIENTS AND MEASUREMENTS: Thirty-three patients with PCOS were specifically selected for being either treated with levothyroxine for a previous diagnosis of hypothyroidism (n = 7), untreated subclinically hypothyroid (n = 2) or euthyroid without levothyroxine treatment (n = 24) before the starting of metformin. The serum levels of TSH and FT(4) were measured before and after a 4-month period of metformin therapy. RESULTS: Thyroid function parameters did not change after starting metformin therapy in euthyroid patients with PCOS. In the 9 hypothyroid patients with PCOS, the basal median serum levels of TSH (3·2 mIU/l, range = 0·4-7·1 mIU/l) significantly (P < 0·05) decreased after a 4-month course of metformin treatment (1·7 mIU/l, range = 0·5-5·2 mIU/l). No significant change in the serum levels of FT4 was observed in these patients. The TSH-lowering effect of metformin was not related to the administered dose of the drug, which was similar in euthyroid as compared with hypothyroid patients with PCOS (1406 ± 589 vs 1322 ± 402 mg/day, respectively; NS). CONCLUSIONS: These results indicate that metformin treatment has a TSH-lowering effect in hypothyroid patients with PCOS, both treated with l-thyroxine and untreated

Complex network analysis of wind tunnel experiments on the passive scalar dispersion in a turbulent boundary layer

In this work, data of passive scalar plumes in a turbulent boundary layer are investigated. The experiments are performed in a&nbsp;wind tunnel where a passive scalar is injected through an L-shaped tube. Two source configurations&nbsp;are analysed for two different tube diameters. The passive scalar concentration is then measured at different distances from the source and wall-normal locations. By exploiting the recent advances of complex networks theory, the concentration time-series are mapped into networks, through the visibility algorithm. The resulting networks inherit the temporal features of the mapped time-series, revealing non-trivial information about the underlying transport process. This work represents an example of the great potentialities of the complex network approach for the analysis of turbulent transport and mixing.</p

Identification of patients at low-risk for thyroidectomy-related hypocalcemia by intraoperative quick PTH

BACKGROUND: Transient hypoparathyroidism is a frequent and challenging complication following total thyroidectomy. The aim of the study was to identify patients at risk of developing thyroidectomy-related hypocalcemia and symptoms by means of the intraoperative quick parathyroid hormone (PTH) assay. METHODS: Eighty-one patients undergoing total thyroidectomy were included in the study. Quick PTH levels were measured at induction of anaesthesia and 10 minutes after total thyroidectomy. A sample of 10 patients who underwent unilateral thyroid lobectomy was considered as a control group. The accuracy of intraoperative PTH decline in predicting postoperative hypoparathyroidism was analysed. RESULTS: After total thyroidectomy, 27 patients (33.3%) developed postoperative hypocalcemia. Symptoms were reported by 21 patients (25.9%). The mean percentage decline of intraoperative quick PTH was 81% in hypocalcemic compared with 39% in normocalcemic patients (P<0.001), and it was 83% in symptomatic compared with 42% in asymptomatic patients (P<0.001). Mean proportion decline of quick PTH after unilateral lobectomy was 20%, significantly lower than the 53% registered after total thyroidectomy (P=0.005). Analysis of variation of intraoperative quick PTH with the receiver operator characteristics (ROC) curve showed a 75.7% decline as the cut-off value predicting postoperative hypocalcemia with the highest accuracy (91.4%) (sensitivity: 81.5% specificity: 96.3% positive likelihood ratio: 22; negative likelihood ratio: 0.2). Regarding the prediction of postoperative symptoms, a 79.5% decline was the most accurate (92.6%) cut-off point (sensitivity: 76.2% specificity: 98.3% positive likelihood ratio: 46; negative likelihood ratio: 0.2). CONCLUSIONS: Quick PTH monitoring during total thyroidectomy is a useful means for identifying low-risk patients for postoperative hypoparathyroidism and candidates for early, safe discharge. Furthermore, it is an objective method complementary to the surgeon's judgement of the intraoperative function of parathyroid glands, which should be implanted in the event of a 75%-80% decline