Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera stokes)

Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells.     

Ewing’s肉瘤细胞X-射线照射后TNF-α和TGF-β mRNA表达的研究

 目的　研究Ewing’s肉瘤细胞系 (RM 82 )X 射线外照射后肿瘤坏死因子 (TNF α)和转化生长因子 (TGF β)mRNA表达水平的变化 ,探讨X 射线诱导内源性TNF α和TGF β产生的可能性及意义。 方法　应用实时荧光RT PCR ,检测接受不同剂量X 线照射 (2Gy ,5Gy ,10Gy ,2 0Gy ,30Gy ,4 0Gy)和受照后不同时间 (1h ,3h ,6h ,12h ,2 4h ,4 8h ,72h)。TNF α和TGF βmRNA表达水平的变化。 结果　RM 82细胞TNF αmRNA表达水平较外照射前显著升高。一方面受照后TNF αmRNA表达逐渐升高 ,照射剂量达 4 0Gy时TNF αmRNA表达水平达高峰 ,为正常对照组的 10 8倍 ;另一方面 ,照射后 3h后TNF αmRNA表达逐渐升高 ,6h达高峰 ,为正常对照组的 18倍。相反 ,TGF βmRNA表达水平X 射线照射前后无显著变化。结论　Ewing’s肉瘤细胞系 (RM 82 )接受X 线照射后TNF αmRNA表达明显升高 ,且呈现时间、剂量依赖性。放射治疗可诱导Ewing’s肉瘤细胞系 (RM 82...     

Synchronous coexpression of epidermal growth factor receptor and cyclooxygenase-2 in carcinomas of the uterine cervix: a potential predictor of poor survival.

PURPOSE: To evaluate the potential of the new prognostic information gained by analyzing the coexpression of epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) in cervical cancer patients. EXPERIMENTAL DESIGN: Sixty-eight patients with International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix, who underwent concurrent chemoradiotherapy between 1993 and 1996, were divided into the following four groups according to their immunoreactivities for EGFR and COX-2 in paraffin-embedded sections: (a). the EGFR-negative/COX-2-negative group (n = 11); (b). the EGFR-negative/COX-2-positive group (n = 8); (c). the EGFR-positive/COX-2-negative group (n = 27); and (d). the EGFR-positive/COX-2-positive group (n = 22). The clinical features, patterns of treatment failure, and survival data in the four groups were compared. RESULTS: Positive immunoreactivity for EGFR and COX-2 was observed in 49 of 68 (72%) and 19 of 68 (28%), respectively. However, no strong correlation was found between the levels of EGFR and COX-2 immunopositivity (R(2) = 0.05, P = 0.07). Patients in the EGFR-positive/COX-2-positive group had a higher likelihood of locoregional recurrence than those in the other three groups (P = 0.02). Of the patients in the four groups, patients positive for both oncoproteins were found to have the worst prognosis with an overall 5-year disease-free survival rate of 55% compared with 91% for the EGFR-negative/COX-2-negative patients, 88% for the EGFR-negative/COX-2-positive patients, and 69% for the EGFR-positive/COX-2-negative patients (P = 0.05, log-rank test). In addition, the synchronous coexpression of the EGFR and COX-2 oncoproteins was found to be an independent prognostic factor by univariate and multivariate analyses (relative risk = 4.0, P = 0.03). CONCLUSIONS: Given these observations, we conclude that the coexpression of EGFR and COX-2 immunoreactivity may be used as a potent molecular risk factor for predicting the poor survival of patients with the International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix.     

Phytosphingosine induces apoptotic cell death via caspase 8 activation and Bax translocation in human cancer cells.

PURPOSE: Sphingolipid metabolites, such as sphingosine and ceramide, are highly bioactive compounds and are involved in diverse cell processes, including cell-cell interaction, cell proliferation, differentiation, and apoptosis. However, the physiological roles of phytosphingosine are poorly understood. In this study, we report that phytosphingosine can potently induce apoptotic cell death in human cancer cells via caspase activation and caspase-independent cytochrome c release. EXPERIMENTAL DESIGN: Phytosphingosine-induced apoptosis was determined by Hoechst 33258 staining, flow cytometric analysis, and DNA fragmentation assay. Involvement of caspases was determined by immunoblot analysis and cell death detection assays after treatment with synthetic inhibitor z-Val-Ala-Asp-fluoromethyl ketone, z-DEVD-fmk, or z-IETD-fmk. Death receptor (DR) dependency was analyzed by examining expression of DRs (Fas, DR4, DR5, TNFR1, and R2), and interaction of Fas-associated death domain and caspase 8. Involvement of the mitochondria pathway was examined by monitoring of the mitochondria membrane potential, cytochrome c release, and Bax translocation. RESULTS: Phytosphingosine-treated cells displayed several features of apoptosis, including increase of sub-G(1) population, DNA fragmentation, and poly(ADP-ribose) polymerase cleavage. We observed that phytosphingosine cause activation of caspase 8 in a DR-independent fashion. Phytosphingosine also induced activation of caspase 9 and 3, loss of mitochondrial membrane potential, and the cytochrome c release from mitochondria. However, we failed to detect Bid cleavage. Moreover, caspase 8 inhibitor z-IETD-fmk did not affect phytosphingosine-induced cytochrome c release and caspase 9 activation, suggesting that phytosphingosine-induced cytochrome c release is caused by caspase 8-independent manner. Phytosphingosine induced mitochondrial translocation of Bax from the cytosol without changes in the protein levels of Bcl-2, Bcl-xL, and Bax. In addition, Bcl-2/Bax interaction was diminished after addition of phytosphingosine. CONCLUSION: These findings indicate that phytosphingosine induces apoptotic cell death in human cancer cells by direct activation of caspase 8, and by mitochondrial translocation of Bax and subsequent release of cytochrome c into cytoplasm, providing a potential mechanism for the anticancer activity of phytosphingosine.     

Erythromycin treatment for gastrointestinal dysmotility in preterm infants

To report our clinical experience on the use of oral erythromycin for the treatment of severe gastrointestinal dysmotility in preterm infants.

Methodology:

A case series study of seven preterm infants (six were very low birthweight) with severe intestinal dysmotility in a tertiary neonatal centre.

Results:

All responded favourably without adverse effects and tolerated full enteral feeding within 1–2 weeks of the commencement of the drug.

Conclusions:

As prolonged total parenteral nutrition carries significant risk of complications, this therapy could be considered in selected preterm infants who fail to establish enteral feeding after an extended period, and in whom an anatomically obstructive lesion of the gastrointestinal tract has been excluded. Meanwhile, we would caution against the widespread implementation of this therapeutic approach until formal evaluation by randomized controlled trials have established the exact role of erythromycin, or its analogues, in the treatment of intestinal dysmotility in preterm infants.     

Quantitative ultrastructure of physiologically identified premotoneuron terminals in the trigeminal motor nucleus in the cat

Little is known about the ultrastructure of synaptic boutons contacting trigeminal motoneurons. To address this issue, physiologically identified premotor neurons (n = 5) in the rostrodorsomedial part of the oral nucleus (Vo.r) were labeled by intracellular injections of horseradish peroxidase (HRP) in cats. The ultrastructure of 182 serially sectioned axon terminals from the five neurons was both qualitatively and quantitatively analyzed. In addition, the effects of the glycine antagonist strychnine, GABA(A) antagonist bicuculline, NMDA antagonist 2-amino-5-phosphonovalerate (APV), and non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on Vo.r-induced postsynaptic potentials in trigeminal motoneurons (n = 11) were examined to evaluate potential signaling substances of the premotor neurons. Labeled boutons made synaptic contacts with either jaw-closing or -opening motoneurons. All the boutons contained pleomorphic vesicles, and most formed a single symmetric synapse either on the somata or on primary dendrites. Morphometric analyses indicated that bouton volume, bouton surface area, apposed surface area, total active zone area, and mitochondrial volume were not different between boutons on jaw-closing and -opening motoneurons. Vesicle number and density, however, were higher for boutons on jaw-closing motoneurons. The five morphological parameters were positively correlated with bouton volume. Vesicle density was the exception, which tending to be negatively correlated. Intravenous infusion of strychnine or bicuculline suppressed Vo.r-induced inhibitory postsynaptic potentials (IPSPs) in jaw-closing motoneurons. Abolition of Vo. r-induced excitatory postsynaptic potentials in jaw-opening motoneurons with APV and CNQX unmasked IPSPs. The present results suggest that premotor neurons in the Vo.r are inhibitory and that positive correlations between the ultrastructural parameters associated with synaptic release and bouton size are applicable to the interneurons, as they are in primary afferents.     

Artery and vein separation using susceptibility-dependent phase in contrast-enhanced MRA

In magnetic resonance angiography, contrast agents are frequently used to help highlight arteries over background tissue. Unfortunately, enhancing veins hamper the visualization of arteries when data are collected over a long period of time after the arterial phase of the contrast agent. To overcome this problem, we have developed a novel imaging and postprocessing method that is capable of eliminating veins by utilizing the susceptibility difference between veins and surrounding tissue. This method was applied in the peripheral vasculature where the vessels are predominantly parallel to the main field and where the blood oxygen level-dependent effect is most pronounced. Results are presented for both long (15.8 msec) and short echo times (7.8 msec) and for sequential and centrally reordered acquisition schemes. The short echo scan approach appears to be the most promising, making it possible to obtain good suppression of the venous signal even when the timing is not perfect or when repeat scans are necessary.