Value of lying-down nystagmus in the lateralization of horizontal semicircular canal benign paroxysmal positional vertigo.

BACKGROUND: Horizontal canal benign paroxysmal positional vertigo is characterized by horizontal direction-changing nystagmus induced by lateral head turning in supine position. According to Ewald's second law, the direction of head turning that creates a stronger response represents the affected side in geotropic nystagmus and the healthy side in apogeotropic nystagmus. However, it may not always be possible to lateralize the involved ear only by comparing the intensity of the nystagmus. We studied the values of nystagmus induced by position change from sitting to supine in the lateralization of horizontal canal benign paroxysmal positional vertigo. METHODS: A retrospective study of 54 patients who had been diagnosed as having horizontal canal benign paroxysmal positional vertigo at the Dizziness Clinic of Seoul National University Bundang Hospital from May 2003 to February 2004 was performed. The directions of the nystagmus induced by lying down were compared with those determined by Ewald's second law. RESULTS: Of the 54 patients, 32 (20 apogeotropic and 12 geotropic) showed horizontal nystagmus induced by lying down. The nystagmus tended to be ipsilesional in apogeotropic patients (80%) and contralesional in their geotropic counterparts (75%). CONCLUSION: In horizontal canal benign paroxysmal positional vertigo, lying-down nystagmus mostly beats toward the involved ear in the apogeotropic type and directs to the healthy ear in the geotropic type. The direction of lying-down nystagmus may help lateralizing the involved ear in horizontal canal benign paroxysmal positional vertigo.     

What constitutes a true hyperdense middle cerebral artery sign?

OBJECTIVES: The 'hyperdense MCA sign' refers to an appearance of increased attenuation of the proximal middle cerebral artery (MCA) that is often associated with thrombosis of the M1 MCA segment and may be the only diagnostic feature on computed tomography early after ischaemic stroke. False positives are recognized, and correct recognition of this sign has, therefore, assumed greater importance with the advent of thrombolytic therapy for stroke. We sought to define objective criteria for hyperdensity of the MCA. METHODS: Brain computed tomographs obtained by a standard protocol in a neuroradiology department were analyzed by a single observer. All consecutive scans reported as exhibiting a hyperdense MCA were compared to controls reported as having normal scans. Ovoid regions of interest were placed over the vessels and cerebral cortices, and the attenuation in Hounsfield units (HU) measured. Absolute attenuation and ratios of one side to the other were compared. RESULTS: MCA attenuation was unrelated to age in cases (n = 18) and controls (n = 80). The mean MCA attenuation was greater in the affected MCA of cases as compared with controls [54.0 HU (99% confidence interval CI 46.7-61.2) vs. 41.3 HU (99% CI 39.7-43.0); p < 0.00001]. Cases were subdivided into true and false positives by the ratio of denser:less dense MCA (within or without the 95% prediction interval for controls). In all true positives, the MCA ratio was > 1.2. 9 of 10 true positives had acute ischaemic stroke; 1 patient had herpes simplex encephalitis, but had MCA attenuation within the 95% CI for controls. False positives had mature cerebral infarction or non-ischaemic pathologies. The ratio of MCA attenuation to adjacent cerebral cortex was significantly higher in both true and false positives than in controls. CONCLUSIONS: Hyperdense MCAs associated with acute ischaemic stroke can be distinguished from normal vessels and false positives by measurement of absolute attenuation of affected and normal vessels: an absolute density of >43 HU and a MCA ratio of >1.2 defined hyperdensity and excluded all other pathologies. Confirmation in other centres is required.     

Pharmacological effects of green tea on the gastrointestinal system

Green tea is rich in polyphenolic compounds, with catechins as its major component. Studies have shown that catechins possess diverse pharmacological properties that include anti-oxidative, anti-inflammatory, anti-carcinogenic, anti-arteriosclerotic and anti-bacterial effects. In the gastrointestinal tract, green tea was found to activate intracellular antioxidants, inhibit procarcinogen formation, suppress angiogenesis and cancer cell proliferation. Studies on the preventive effect of green tea in esophageal cancer have produced inconsistent results; however, inverse relationships of tea consumption with cancers of the stomach and colon have been widely reported. Green tea is effective to prevent dental caries and reduce cholesterols and lipids absorption in the gastrointestinal tract, thus benefits subjects with cardiovascular disorders. As tea catechins are well absorbed in the gastrointestinal tract and they interact synergistically in their disease-modifying actions, thus drinking unfractionated green tea is the most simple and beneficial way to prevent gastrointestinal disorders.     

Effects of antisense oligonucleotide-mediated depletion of tumor necrosis factor (TNF) receptor 1-associated death domain protein on TNF-induced gene expression

Tumor necrosis factor (TNF) receptor 1-associated death domain protein (TRADD) is an adaptor protein known to be involved in the TNF signaling pathway as well as signaling of other members of the TNF receptor superfamily, including DR3, DR6, p75(NTR), and the Epstein-Barr virus latent membrane protein 1. Current knowledge of the function of the adaptor protein has been derived from studies examining its over-expression in either wild-type or mutated forms. In this study, we analyzed the consequences of antisense oligonucleotide (ASO)-mediated depletion of endogenous TRADD on TNF induction of inflammation-related gene products, such as intercellular adhesion molecule-1, and associated kinase signaling pathways in human umbilical vein endothelial cells. A broader perspective of TRADD's role in TNF signaling was indicated by microarray gene expression analysis, where 20 of 24 genes that showed a 5-fold or greater increase in TNF-induced mRNA expression levels displayed a reduction in TNF-induced expression as a consequence of ASO-mediated knockdown of TRADD. Reduced activation of the nuclear factor-kappaB and c-Jun NH(2)-terminal kinase pathways, as measured by IkappaB-alpha protein levels and the extent of c-Jun phosphorylation, was also observed. These results indicate usage of antisense inhibitors of TRADD expression for modulating diseases associated with TRADD-dependent signal transduction pathways.     

30例感染性心内膜炎的临床分析

目的:探讨感染性心内膜炎(IE)的病因,致病微生物的变迁及抗生素的选择。方法:对1995年5月～2003年8月间住院的30例IE患者的临床资料进行回顾性分析。结果:风湿性心脏瓣膜病为其主要的基础心脏病变。链球菌在致病微生物中依然居首位,但凝固酶阴性葡萄球菌(CNS)等其它菌种逐渐增多,且对青霉素耐药发生率高,为临床诊治造成困难。结论:对于IE患者应尽可能早期明确诊断,早期选用有效的抗生素。CNS在IE的致病微生物中的地位有待进一步提高。