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The short cytoplasmic tail of mouse CD1d (mCD1d) is required for its endosomal localization, for the presentation of some glycolipid Ags, and for the development of Valpha14i NKT cells. This tail has a four-amino acid Tyr-containing motif, Tyr-Gln-Asp-Ile (YQDI), similar to those sequences known to be important for the interaction with adaptor protein complexes (AP) that mediate the endosomal localization of many different proteins. In fact, mCD1d has been shown previously to interact with the AP-3 adaptor complex. In the present study, we mutated each amino acid in the YQDI motif to determine the importance of the entire motif sequence in influencing mCD1d trafficking, its interaction with adaptors, and its intracellular localization. The results indicate that the Y, D, and I amino acids are significant functionally because mutations at each of these positions altered the intracellular distribution of mCD1d and reduced its ability to present glycosphingolipids to NKT cells. However, the three amino acids are not all acting in the same way because they differ with regard to how they influence the intracellular distribution of CD1d, its rate of internalization, and its ability to interact with the mu subunit of AP-3. Our results emphasize that multiple steps, including interactions with the adaptors AP-2 and AP-3, are required for normal trafficking of mCD1d and that these different steps are mediated by only a few cytoplasmic amino acids.

Background/aims: SU5416 is a potent inhibitor of receptor tyrosine kinases, including those of the vascular endothelial growth factor receptor, stem cell factor receptor, and platelet-derived growth factor receptor. Because of the overwhelming evidence favoring the role of aberrant hepatocyte growth factor (HGF)/Met signaling in the pathogenesis of various human cancers, various inhibitor strategies have been employed to therapeutically target this receptor., Methods: Cell proliferation was determined by incorporation of [(3)H] thymidine. Invasiveness was assayed in Boyden Chambers with 8 microm Matrigel coated filters. Phosphorylation of ERK1/2, Akt by HGF stimulation was detected by Western blotting., Results: We found that SU5416 inhibited motility scattering and the invasive activity of a hepatocellular carcinoma cell line HepG2 in vitro and growth in primary cultured hepatocytes induced by HGF. Consequently, tyrosine autophosphorylation of the c-met induced by HGF was inhibited in these cells by SU5416 in a dose-dependent manner. Furthermore, ERK1/2 and Akt phosphorylation, the signaling events down-stream of c-met activation were reduced. Moreover, SU5416 caused reversion in NIH3T3 fibroblasts transformed by the oncogenic form of the receptor, Tpr-Met., Conclusions: Inhibition of various solid tumors growth and metastasis by SU5416 may be partially attributed to blocking activation of the hepatocyte growth factor receptor.

Objective: To explore a simple speedy specific and sensitive method to detect specific IgM (sIgM) and IgG (sIgG) antibodies of hemorrhagic fever with renal syndrome (HFRS),and to study the therapeutic effects of integrated traditional Chinese and western medicine on HFRS., Methods: The serum of 559 patients with HFRS were tested with colloidal gold immuno-dot assay (CGIDA) for sIgM and sIgG antibodies and compared with enzyme linked immunosorbent assay (ELISA) or indirect fluorescent antibody test (IFAT). One hundred and one patients with HFRS were randomized into treatment group (n=50),treated with Kuhuang Injection, Shenmai Injection and Huangqi Liquid) and control group (n=51),treated with Ribarvirin and Ganlixin Injection)., Results: The positive rate of sIgM detected with CGIDA was 70.8% and the positive rate of sIgG detected with CGIDA was 87.5%. The days for fever decline, symptoms alleviation and sign relief between the treatment group and control group were similar (P>0.05). The days for recovery of kidney function in the control group was less than that in the treatment group (P<0.01). The rate of crossing shock stage in the treatment group was higher than that of the control group (P<0.01)., Conclusion: CGIDA was more simple, speedy, specific and sensitive than ELISA or IFAT in detecting the sIgM or sIgG antibodies in serum of patients with HFRS. Although the sensitivity of CGIDA was lower than that of ELISA the CGIDA had no false positive reaction the sensitivity of CGIDA was higher than that of IFAT on detecting IgG. The effect of the treatment group was similar to that of the control group. But the crossing shock stage rate in the treatment group was higher than that of the control group while the control group was better than the treatment group in recovering the kidney function.

The special physical state of the sphingolipid-enriched membranes with characteristic lipid composition, presently one of the most controversial foci in cell biology, provides the essential environment for the proteins inside to be involved in the related physiological processes. The role of gangliosides, an important component of the membranes, deserves attention. The present investigation using several biophysical techniques indicates that ganglioside GM(1) induces the phase separation in the sphingomyelin membrane with 5 mol% cholesterol and regulates the membrane structure. The results of differential scanning calorimetry show that a higher T(m), GM(1)-rich phase emerges behind the lower T(m), sphingomyelin-rich phase with the incorporation of GM(1) into the sphingomyelin/cholesterol bilayers; and the GM(1)-rich phase dominates the membrane when the proportion of GM(1) reaches about 20 mol%. Fluorescence quenching further shows that the separation of the two domains is independent of temperature, occurring both in the gel phase and in the liquid phase. Laser Raman spectroscopy and fluorescence polarization suggest that the order of hydrocarbon chains increases and membrane fluidity decreases with increase in GM(1) content. Use of the fluorescence probe merocyanine-540 and electron microscopy reveals that the insertion of GM(1) leads to an increase in the spatial density of the lipid headgroups and a decrease in the curvature of the sphingomyelin/cholesterol bilayers. In sums, both the hydrophilic sugar heads and the hydrophobic hydrocarbon chains of GM(1) contribute to the regulation of membrane architecture. We suggest that the convex curvature of ganglioside-enriched membrane could be involved in forming and maintaining the characteristic flask-shaped invagination of caveolae.

Addition of a small amount of ganglioside GM(1) to phosphatidylserine (PS) liposomes, a gradual increase of protein kinase C (PKC) activity was recorded up to about 2 mol% GM(1) where the maximal enzyme activity was obtained. Then the activity of PKC began to decline and even turned to be inhibited with the further increase of GM(1) content. It was also indicated that GM(1)/PS binary liposomes had the highest membrane fluidity and very low spatial density of lipid headgroups which was demonstrated in the MC-540 studies due to the interposition of GM(1) when the liposomes contained about 2 mol% GM(1). Besides, the liposomes containing about 2 mol% GM(1) provided a more hydrophobic environment for PKC than the liposomes containing less or more GM(1) which was indicated in the Acrylodan experiments. These factors commonly induced PKC to be stimulated maximally. Whether at the lower or higher GM(1) content, the membrane structure was not the most suitable to support the activity of PKC, which declined as a consequence.

Objective: To sum up the application experience of the sural nerve island flap pedicled with the collateral vessels., Methods: From 1997, the retrograde-flow sural nerve island flaps pedicled with collateral vessels were performed to repair the soft tissues defects of the shank in 3 cases, ankle in 3 cases and foot in 8 cases., Results: Twelve flaps were survived, one flap was partially necrosed and one flap was necrosed. Among them, 10 wounds healed by first intention, 3 cases were healed after changing dressing and the one necrosed flap was repaired by free flap transplantation. Nine cases were followed up for 3 to 21 months and had fine appearance and function. The flap texture was similar to normal skin, the sensation of flap partially recovered after 6 months., Conclusion: The flap has more reliable blood supply and great rotation arc, it is easy to resect with little injury. It is excellent for repairing the soft tissues defect in the anterior leg, ankle and proximal half of foot. It is more significant while the main blood vessels are damaged.

This paper reported an epidemiological investigation on human and animals infection of eperythrozoon in 1 provinces. The results showed that eperythrozoon infection appeared in human as well as in swines, sheep, cats, donkeis and chickens. Due to geographical variations, the infection rates showed a significant difference, both in human and animals. The infection rate was not associated with sex, age or occupation in human, but was associated with seasons in animals. High peak of infection rates in animals was in May, June, July and August.