The Effect of Hyperthermic Pretreatment in a Neonatal Rat Model of Hypoxic-ischemic Brain Injury

PURPOSE: Perinatal asphyxia is an important cause of neonatal mortality and subsequent lifelong neurodevelopmental handicaps. Although many treatment strategies have been tested, there is currently no clinically effective treatment to prevent or reduce the harmful effects of hypoxia and ischemia in humans. In the clinical setting, maternal hyperthermia induces adverse effects on the neonatal brain, but recent studies have shown that hyperthermic pretreatment (PT) plays some role in hypoxic-ischemic (HI) injuries of the developing brain. The present study investigated the effect of hyperthermic PT on HI brain injuries in newborn rats. METHODS: HI was produced in 7-day-old neonatal rats by unilateral common carotid artery ligation, followed by hypoxia with 8% oxygen at 38degrees C for 2 hours. Twenty-four hours before HI, one-half of the pups were exposed to a 40degrees C environment for 2 hours. The severity of the brain injury was assessed 7 days after the HI. RESULTS: Hyperthermic PT reduced the gross and histopathologic findings of brain injury from 64.7 to 31.2% (P<0.05). There were no differences in location and severity of injury between the pretreated and control brains. CONCLUSION: These findings indicate that hyperthermic PT provides neuroprotective benefits on HI in the developing brain. Also, these findings suggest maternal hyperthermia may have protective effect on perinatal HI brain injuries.

DNA methylation of TPEF gene in head and neck squamous cell carcinoma cell lines

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. The molecular mechanisms involved in the development and progression of these carcinomas are not well known. Abnormalities of genomic methylation patterns have been attributed a role in carcinogenesis and local de novo methylation at tumor suppressor loci was held to be involved in silencing of tumor suppressor genes. Using Ms APPCR, we previously isolated a hypermethylated fragment corresponded to the 5'end of TPEF gene from primary liver and lung cancer cells. To confirm the inactivation of TPEF gene by hypermethylation in HNSCC, we investigated correlation between methylation pattern and expression of TPEF in 10 HNSCC cell lines. In methylation analysis such as combined-bisulfite restriction analysis(COBRA) and bisulfite sequencing, only RPMI 2650 showed none methylated pattern and another 9 cell lines showed dense methylation. The TPEF gene expression level analysis using RT-PCR showed that these 9 cell lines had not or significantly low expression levels of TPEF as compared with RPMI 2650. In addition, the increase of TPEF reexpression by 5-AzaC as demethylating agent in 9 cell lines also indicated that TPEF expression was regulated by hypermethylation. These results of this study demonstrate that epigenetic silencing of TPEF gene by aberrant methylation could play an important role in HNSCC carcinogenesis.

Paraganglioma of Cauda Equina: A case report

The clinical and pathological features of a paraganglioma arising in the cauda equina is described and compared with previous reports. The right microscopic fetures were similar to those of paragangliomas from other sites, with a 'Zellballen' pattern of cells containing arzyrophil granules. Immunohistocytochemical stains for neurone specific enolase, S-100 protein, cytokeratin were positive, but stains for glial fibrillary acidic protein were negative. Electron microscopy showed densely staining membrane-bound granules, cilia like structures and fibros bodies in the cytoplasm. The last two features only occur in paragangliomas from this site. The pathological findings suggest that paragangliomas in this site arise from pre-existing paraganglia, possibly of the visceral autonomic group.