Expression of orexin-A (hypocretin-A) in the hypothalamus after traumatic brain injury: A postmortem evaluation.

Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity. The key component of TBI pathophysiology is traumatic axonal injury (TAI), commonly referred to as diffuse axonal injury (DAI). Coma is a serious complication which can occur following traumatic brain injury (TBI). Recently, studies have shown that the central orexinergic/ hypocretinergic system exhibit prominent arousal promoting actions. Therefore, the purpose of this study is to investigate by immunohistochemistry the expression of beta-amyloid precursor protein (ß-APP) in white matter of parasagittal region, corpus callosum and brainstem and the expression of orexin-A (ORXA) in the hypothalamus after traumatic brain injury. RESULTS: DAI was found in 26 (53.06%) cases, assessed with ß-APP immunohistochemical staining in parasagittal white matter, corpus callosum and brainstem. Orexin-A immunoreactivity in hypothalamus was completely absent in 5 (10.2%) of the cases; moderate reduction of ORXA was observed in 9 (18.4%) of the cases; and severe reduction was observed in 7 (14.3%) of the cases. A statistically significant correlation was found between ß-APP immunostaining in white matter, corpus callosum and brainstem in relation to survival time (p < 0.002, p < 0.003 and p < 0.005 respectively). A statistically positive correlation was noted between ORX-A immunoreactivity in hypothalamus to survival time (p < 0.003). An inverse correlation was noted between the expression of ß-APP in the regions of brain studied to the expression of ORX-A in the hypothalamus of the cases studied (p < 0.005). CONCLUSIONS: The present study demonstrated by immunohistochemistry that reduction of orexin-A neurons in the hypothalamus, involved in coma status and arousal, enhanced the immunoexpression of ß-APP in parasagital white matter, corpus callosum and brainstem.

Thyroid Gland as a Target of Secondary Malignancies - an Autopsy Study and Review Data.

AIM: Secondary malignancies of the thyroid gland are rarely diagnosed but their incidence at autopsy is not uncommon. MATERIALS AND METHODS: To investigate the clinicopathological features of patients with metastatic tumours of the thyroid gland, we reviewed autopsy records and pathological features of 36 cases with thyroidal secondary tumours from 266 cases of malignant neoplasias (excluding cases of primary thyroid cancer), over a 16-year period. RESULTS: There were 19 men and 17 women in the study, ranging in age from 37 to 95 years (mean 70.4 years). The incidence of metastasis in thyroid gland was 0.9% in all autopsy cases, and 13.53% of the malignant tumours. The majority were carcinomas of epithelial origin. The lung was the most common primary tumour site (33.3%), followed by the breast (8.33%) and the kidney (8.33%). The most common non-epithelial malignancy was lymphoma, followed by leukaemia (total of both 25%). As for the microscopic morphological observations, diffuse infiltration pattern of tumour cells was noted in 63.89% of the cases, the formation of nodules in 33.33% of the cases and contiguous invasion in 2.79% of the cases. There were 35.71% cases of metastases associated with multinodular goitre and 28.57% cases associated with papillary microcarcinoma. CONCLUSION: Our study indicates that thyroid secondary malignancies are not infrequent and may constitute a diagnostic problem. Lung cancer is the most common neoplasm that metastasizes to the thyroid gland in north-western Greek population.