Thermogenic response and leptin levels rise after recovery of the euthyroid state

OBJECTIVE

The aims of the study were to compare: a) the thermogenic responses in subclinical hypothyroidism (SH) and euthyroid state; b) the relationship between thermogenic response and leptin level.

METHODS

Thirty women diagnosed with SH (mean age 39.9+/-4.1 yr; body mass index 23.2+/-2.5 kg/m(2)) were enrolled in the study. Thyroid function tests, leptin, and lipid profiles were measured during SH and after stable euthyroidism was recovered. Thermogenic response was measured by Water Immersion Calorimetry during SH and after the euthyroid state was attained.

RESULTS

The mean level of thermogenic response was found to be 1.45+/-0.43 kcal/kg*h in women with SH. It changed to 1.54+/-0.77 kcal/kg*h (p=0.01) in the euthyroid state; the change was statistically significant. Mean level of leptin was found to be 7.22+/-2.6 ng/ml in SH; and 15.8+/-8.0 ng/ml in the euthyroid state. There was a positive correlation between leptin and free T(3) (r=0.460, p=0.009) levels in SH. There were positive correlations between leptin level and fat mass in SH (r=0.820, p=0.01) and in the euthyroid state (r=0.700, p=0.03).

CONCLUSIONS

No correlations were found between thermogenic response and leptin levels in SH and in the euthyroid state. Thermogenic response and leptin levels rose after the euthyroid state was recovered.

The prevalence of RET/PTC mutations in papillary thyroid cancers in Turkish population and its relation between tumor histopathology and prognostic factors

OBJECTIVE

In recent years, thyroid cancer has been at the forefront of molecular pathology as a result of the consequences of the Chernobyl disaster and the recognition of the role of RET/PTC rearrangements in papillary thyroid carcinomas (PTCs). Correlation of RET/PTC expression with clinical outcome is controversial. This study aims to identify the prevalence of RET/PTC oncogene expression in Turkey, and to investigate the correlation between RET/PTC oncogene expression and the known prognostic factors of PTC in 101 patients.

METHODS

The RET rearrangements were examined by means of reverse transcriptase-polymerase chain reaction analysis, with primers flanking the chimeric region. Statistical evaluation was performed by using Independent samples t-test, One-sample Chi-square test and Pearson Chi-square or Fisher's Exact Test.

RESULTS

RET/PTC was determined positive in 67(66.3%) of totally 101 patients (p<0.001). RET/PTC1 in 32(31.7%), RET/PTC3 in 21(20.8%), RET/PTC1+RET/PTC3 both in 10(9.9%) patients were found to be positive. There was RET/PTC2 positiveness in two patients, RET/PTC2,3 positiveness in one patient, and RET/PTC1,2,3 positiveness in one patient. No statistical difference was found between RET/PTC1 and RET/PTC3. None of genetico-clinical analyses showed any significant association between RET/PTC expression and the clinical and pathological features of the cancers.

CONCLUSION

While this prevalence of the RET/PTC is less than RET/PTC frequency seen after Chernobyl in Belarus, its prevalence in our region is also high (66.3%). As a result, no significant correlation was found in between prognosis and RET/PTC frequency.

Fas/Fas ligand gene polymorphism in patients with papillary thyroid cancer in the Turkish population

OBJECTIVE

Fas ligand (FasL) is an apoptotic agent and a member of tumor necrosis factor (TNF) family. FasL exists in cytotoxic T lymphocyte (CTL) and natural killer (NK) cells, and it is increased in tumor cell membrane. On the contrary, CTL and NK are bound to Fas on the surfaces of cell membrane; this triggers apoptosis in cytotoxic cells and leads to their death. This system plays an important role in eliminating viral infections and cancer cells. Malfunction of this system results in the development and spread of the malignancy. This study aims at evaluating the influence of Fas and FasL gene polymorphism in papillary thyroid cancer (PTC) in the Turkish population.

RESEARCH DESIGN AND METHODS

Forty-five patients with PTC and 100 healthy controls were included in this study. The diagnosis of PTC was confirmed by histopathologic examination after surgery. The evaluation of genotype for Fas 670 A/G and FasL 843 C/T gene polymorphism was performed using the PCR-restriction fragment length polymorphism (RFLP) method.

RESULTS

The evaluation of Fas/FasL genotype and gene allele frequency did not show statistically significant differences between the patient and control group (p>0.05). In addition, the univariate analysis did not reveal a statistically significant relationship between the size of the nodule and the Fas/FasL gene polymorphism in patients with PTC.

CONCLUSIONS

As in other types of malignancy, genetic factors in the pathogenesis of PTC may also show changes in different populations. Fas/FasL gene polymorphysms are possible that different mechanisms function in apoptosis balance in PTC development.

Power Doppler US patterns of vascularity and spectral Doppler US parameters in predicting malignancy in thyroid nodules

AIM

The purpose of this study was to determine whether spectral Doppler ultrasound (US) parameters, including resistive index (RI) and maximal systolic velocity (MSV), or vascular pattern can be used to distinguish malignant from benign thyroid nodules.

MATERIALS AND METHODS

We prospectively examined 169 thyroid nodules in 134 patients undergoing sonographically guided fine-needle aspiration biopsy (FNAB). Vascularity as determined by power Doppler US imaging was defined as absent, perinodular alone, or intranodular. For each nodule, the RI and MSV values were recorded as the average of the recordings obtained. Results of the FNAB and surgical pathological examination, if available, were used as a proof of final diagnosis to categorize all nodules as benign or malignant.

RESULTS

Seven nodules were excluded from study because of non-diagnostic FNAB results due to hypocellular or insufficient cytological material. Of the remaining nodules, nine were malignant (all confirmed at surgery) and 153 were benign. Of the 145 nodules with intranodular vascularity, nine (6.2%) were malignant and the remaining 136 (93.8%) were benign. The malignant nodules had a mean RI of 0.60 on intranodular and 0.58 on perinodular arteries. These values were not significantly higher than those associated with benign nodules (RI=0.57 and RI=0.56, respectively). Malignant nodules had a mean MSV of 20.4cm/s on intranodular and 35.3cm/s on perinodular arteries that were also not significantly different from those associated with benign nodules (p>0.05).

CONCLUSION

The results of this study indicate that Doppler US characteristics including vascular pattern, RI and MSV are not useful parameters for distinguishing malignant from benign thyroid nodules. Therefore, Doppler US characteristics including vascular pattern, RI and MSV values of thyroid nodules can not be used as a diagnostic method to determine which nodules should undergo FNAB.