Background and Purpose-It is still controversial whether elevated plasma homocysteine and the C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene are risk factors for stroke. The aim of the present study was to investigate the association between the 2 factors and stroke in Chinese in a large case-control study. Methods-We recruited 1823 stroke patients (807 cerebral thrombosis, 513 lacunar infarction, 503 intracerebral hemorrhage) and 1832 controls. Total plasma homocysteine was determined by high-performance liquid chromatography. C677T polymorphism was genotyped by polymerase chain reaction and HinfI digestion. Results-Total plasma homocysteine levels were significantly higher in cases than controls (median, 14.7 versus 12.8 mol/L; PϽ0.001) and associated with an increased risk of 1.87-fold (95% confidence interval [CI], 1.58 to 2.22) for overall stroke, 1.72-fold (95% CI, 1.39 to 2.12) for cerebral thrombosis, 1.89-fold (95% CI, 1.50 to 2.40) for lacunar infarction, and 1.94-fold (95% CI, 1.48 to 2.55) for intracerebral hemorrhage. The C677T mutation of the MTHFR gene was positively correlated with plasma homocysteine levels in both controls (␤ϭ0.250, PϽ0.001) and cases (␤ϭ0.272, PϽ0.001) and more frequently in cases than in controls (47.0% versus 44.2%, Pϭ0.017). The TT genotype was associated with an increased risk for overall stroke (odds ratio, 1.27; 95% CI, 1.04 to 1.56) and thrombotic stroke (odds ratio, 1.37; 95% CI, 1.06 to 1.78). Conclusions-The C677T polymorphism of the MTHFR gene was associated with increased risk of cerebral thrombotic stroke in Chinese. Total plasma homocysteine was correlated with both ischemic and hemorrhagic stroke, suggesting potential initiation of homocysteine-lowering therapy in this population.

p63 is a recently identified homologue of the tumor suppressor gene TP53, which encodes multiple isotypes with transactivating, death-inducing and dominant-negative activities. p63 is expressed in basal cells of squamous epithelia and many kinds of tumors. To explore the penetrance of p63 in esophageal cancer, we analyzed p63 expression in squamous cell carcinomas, adjacent dysplasia and histologically normal mucosa of the esophagus by combination of immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the ⌬Np63 mRNA was easily detectable in all malignant and histologically normal tissues, whereas TAp63 presented extremely low or no expression. The p63 protein was highly expressed in 50 of 51 tumor tissues without significant difference in gender, age, stage and grade. Ten of 11 dysplasia exhibited strong p63 staining in all abnormal cells. Interestingly, p63 expression was observed in 96% (45/47) histologically normal epithelia adjacent to the cancerous tissues but only in 47% (14/30) mucosa far from tumors. Most of the epithelia far from tumors showed weaker staining than that adjacent to the cancerous tissues. In all the histologically normal epithelia with p63 expression, irrespective of the distance from the tumors, immunohistochemical reaction was restricted to the basal and suprabasal cell layers. Our data suggested that ⌬Np63 is the major isotype expressed in epithelia and tumors of the esophagus. Elevated expression of p63 is probably an early event in esophageal squamous cell carcinomas, which may play a significant role in the development of the disease.

Our previous work has suggested that traumatic noise activates Rho-GTPase pathways in cochlear outer hair cells (OHCs), resulting in cell death and noise-induced hearing loss (NIHL). In this study, we investigated Rho effectors, Rho-associated kinases (ROCKs), and the targets of ROCKs, the ezrin-radixin-moesin (ERM) proteins, in the regulation of the cochlear actin cytoskeleton using adult CBA/J mice under conditions of noise-induced temporary threshold shift (TTS) and permanent threshold shift (PTS) hearing loss, which result in changes to the F/G-actin ratio. The levels of cochlear ROCK2 and p-ERM decreased 1 h after either TTS- or PTS-noise exposure. In contrast, ROCK2 and p-ERM in OHCs decreased only after PTS-, not after TTS-noise exposure. Treatment with lysophosphatidic acid, an activator of the Rho pathway, resulted in significant reversal of the F/G-actin ratio changes caused by noise exposure and attenuated OHC death and NIHL. Conversely, the down-regulation of ROCK2 by pretreatment with ROCK2 siRNA reduced the expression of ROCK2 and p-ERM in OHCs, exacerbated TTS to PTS, and worsened OHC loss. Additionally, pretreatment with siRNA against radixin, an ERM protein, aggravated TTS to PTS. Our results indicate that a ROCK2-mediated ERM-phosphorylation signaling cascade modulates noise-induced hair cell loss and NIHL by targeting the cytoskeleton.

Lysophosphatidic acid (LPA) is a bioactive phospholipid with diverse functions mediated via G-protein-coupled receptors (GPCRs). In view of the elevated levels of LPA in acute myocardial infarction (MI) patients we have conducted studies aimed at identifying specific LPA receptor subtypes and signaling events that may mediate its actions in hypertrophic remodeling. Experiments were carried out in cultured neonatal rat cardiomyocytes (NRCMs) exposed to LPA and in a rat MI model. In NRCMs, LPA-induced hypertrophic growth was completely abrogated by DGPP, an LPA1/LPA3 antagonist. The LPA3 agonist OMPT, but not the LPA2 agonist dodecylphosphate, promoted hypertrophy as examined by 3[H]-Leucine incorporation, ANF-luciferase expression and cell area. In in vivo experiments, LPA1, LPA2 and LPA3 mRNA levels as well as LPA1 and LPA3 protein levels increased together with left ventricular remodeling (LVRM) after MI. In addition, LPA stimulated the phosphorylation of Akt and p65 protein and activated NF-kappaB-luciferase expression. Inhibitors of PI3K (wortmannin), mTOR (rapamycin), and NF-kappaB (PDTC or SN50) effectively prevented LPA-induced 3[H]-Leucine incorporation and ANF-luciferase expression. Furthermore, ERK inhibitors (U0126 and PD98059) suppressed LPA-stimulated activation of NF-kappaB and p65 phosphorylation whereas wortmannin showed no effect on NF-kappaB activation. Our findings indicate that LPA3 and/or LPA1 mediate LPA-induced hypertrophy of NRCMs and that LPA1 and LPA3 may be involved in LVRM of MI rats. Moreover, Akt and NF-kappaB signaling pathways independently implicate in LPA-stimulated myocardial hypertrophic growth.