Homogentisic acid metabolism inhibits papillary thyroid carcinoma proliferation through ROS and p21-induced cell cycle arrest.

Thyroid cancer is one of the most common primary endocrine malignancies worldwide, and papillary thyroid carcinoma (PTC) is the predominant histological type observed therein. Although PTC has been studied extensively, our understanding of the altered metabolism and metabolic profile of PTC tumors is limited. We identified that the content of metabolite homogentisic acid (HGA) in PTC tissues was lower than that in adjacent non-cancerous tissues. We evaluated the potential of HGA as a novel molecular marker in the diagnosis of PTC tumors, as well as its ability to indicate the degree of malignancy. Studies have further shown that HGA contributes to reactive oxygen species (ROS) associated oxidative stress, leading to toxicity and inhibition of proliferation. In addition, HGA caused an increase in p21 expression levels in PTC cells and induced G1 arrest. Moreover, we found that the low HGA content in PTC tumors was due to the low expression levels of tyrosine aminotransferase (TAT) and p-hydroxyphenylpyruvate hydroxylase (HPD), which catalyze the conversion of tyrosine to HGA. The low expression levels of TAT and HPD are strongly associated with a higher probability of PTC tumor invasion and metastasis. Our study demonstrates that HGA could be used to diagnose PTC and provides mechanisms linking altered HGA levels to the biological behavior of PTC tumors.

Clinical characteristics, treatment and prognosis of angiocentric glioma.

Angiocentric glioma (AG) is a rare subtype of neuroepithelial tumor in children and young adults that commonly presents with seizures. To study the clinical characteristics, treatment and prognosis of patients with AG, the features of two cases of AG were described and 108 cases reported in the literature were assessed. The cases of the present study were two males aged 8 and 16 years, who mainly presented with seizures. MRI revealed superficial, non-enhanced lesions in the left temporal and right frontal lobe, respectively. The two patients underwent gross total resection (GTR) and remained seizure-free without neurological deficits after 3.5 and 2.5 years, respectively. Histopathological examination revealed that the tumors consisted of monomorphous cells that surrounded the blood vessels and neurons in the cerebral cortex, and formed concentric sleeves or pseudorosettes. Furthermore, immunostaining indicated that the diffuse infiltrative neoplastic cells were positive for glial fibrillary acidic protein and a dot-like pattern of epithelial membrane antigen was observed. AG mostly appeared similar to low-grade gliomas on MRI. GTR of the lesions was curative and radiation or chemotherapy were not required. AG typically has a favorable prognosis, with low mortality and incidence of disability.

The role of N-methyl-D-aspartate receptor in Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive disorder and memory dysfunction. This kind of cognitive impairment is closely related to synaptic plasticity, in which N-methyl-D-aspartate receptor (NMDAR), which is one of the glutamate receptors, plays a critical role. Therefore the present study was designed to investigate whether the cognitive impairment of AD rat model has relation to the change of NMDAR. The adult male rats were randomly divided into three groups: control, AD and AD+APV (the competitive but not selective blocker of NMDAR) groups. The synaptic plasticity was measured by recording long-term potentiation (LTP) and depression (LTD) in the perforant path (PP) to dentate gyrus (DG) of hippocampus. The spatial memory and reversal learning were examined by Morris water maze (MWM) test. Results showed that the spatial learning performance of MWM was significantly impaired in AD group compared to that of control group. Rats of APV group showed a higher LTP and better performance in spatial memory, but worse performance in reversal learning test and lower LTD than those of AD group. In conclusion, the high concentration of APV influenced LTD and enhanced LTP in AD rats through changing the proportion of NMDAR, which suggested that the change of NMDAR may participate in the pathogenesis of AD at the synaptic level.

[Efficacy and safety of rapamycin in treatment of children with epilepsy complicated with tuberous sclerosis].

OBJECTIVE: To evaluate the therapeutic effect and safety of rapamycin in treatment of children with tuberous sclerosis complex (TSC) complicated with epilepsy. METHOD: This was an open-label, prospective, self-controlled study. From Sep. 2011 to Sep. 2013, 52 patients with the diagnosis of tuberous sclerosis complicated with epilepsy receiving rapamycin treatment for at least 24 weeks were enrolled. RESULT: Of the 52 children, 34 were male and 18 female. The median age at onset of epilepsy was 4.8 months (4 days-49 months), the median age for treatment with rapamycin was 27 months (4.5-172.5 months). Ten children had a family history of TSC. In 24 children TSC gene detection was carried out, among whom TSC1 mutation was detected in 4 cases and TSC2 mutation in 20. Before rapamycin therapy, 59.62%, (31/52) patients took more than 3 antiepileptic drugs, of whom 10 cases even took more than 5 kinds of antiepileptic drugs. Fifty-two patients received rapamycin treatment for 24 weeks, seizure free rate was 25.00% (13 cases), the total effective rate was 73.08% (38 cases); 31 cases received treatment for 48 weeks, seizure free 6 cases, total effective 23 cases; 17 cases accepted treatment for 72 weeks, seizure free 5 cases, total effective 13 cases; 12 cases received treatment for 96 weeks, seizure free 3 cases, total effective 9 cases. With the decrease of seizure attacks, use of antiepileptic drug types were reduced simultaneously, they had a negative correlation. Before rapamycin therapy, the average frequency of seizures was 70.27 times/d, the number of antiepileptic drug kinds was 1.30. After 24, 48, 72, 96 weeks' treatment, the average seizure frequency was reduced to 1.94-2.80 times /d and the antiepileptic drugs were reduced to 0.83-0.97 kinds. On every visit during the follow-up, blood and urine routine tests, liver and kidney function test showed no abnormality in the 52 cases. The drug dosage was 1 mg/(m(2)×d), average 0.7 mg/d (0.35-1.20 mg/d). Blood concentrations of rapamycin remained below 10 µg/L (average 6.5 µg/L). The main side effect was oral ulcer which happened in 23.08% (12/52). The oral ulcer would disappeared 2-3 days later. 17.31% (9/52 cases) had upper respiratory infection. CONCLUSION: Rapamycin was effective in children with tuberous sclerosis and epilepsy with few adverse reactions. The daily dose of rapamycin for children patients is 1 mg/m(2), which has a certain effect on seizures and a good safety profile.