Association of catechol-O-methyltransferase gene polymorphisms with schizophrenia and negative symptoms in a Chinese population

The gene encoding Catechol-O-methyltransferase (COMT), a dopamine catabolic enzyme, has been associated inconsistently with schizophrenia in spite of consistent evidence for dopaminergic dysfunction in the prefrontal cortex (PFC) of schizophrenia. Since one contribution to this inconsistency might be genetic heterogeneity, this study investigated whether the COMT gene was associated with the development and symptoms of schizophrenia in relatively genetically homogeneous Chinese schizophrenic patients. We analyzed two polymorphisms (rs740603 and rs4818) of the COMT gene in a case-control study of 604 Han Chinese (284 patients and 320 controls). The patients' psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). We found no significant differences in the rs740603 and rs4818 genotype and allele distributions between the patient and control groups. Quantitative trait analysis by the UNPHASED program showed that the rs740603 and rs740603(G)-rs4818(G) haplotypes were associated with negative symptoms in the schizophrenic patients, particularly among female patients. Thus, the COMT gene polymorphisms may not contribute to the susceptibility to schizophrenia, but may contribute to the negative symptoms of schizophrenia among Han Chinese.     

Different multiple regeneration capacities of motor and sensory axons in peripheral nerve

Abstract After peripheral nerve injury, axons often project sprouts from the node of Ranvier proximal to the damage site. It is well known that one parent axon can sprout and maintain several regenerating axons. If enough endoneurial tubes in the distal stump are present for the regenerating axons to grow along, then the number of mature myelinated nerve fibers in the distal stump will be greater than the number in the proximal stump. "Multiple regeneration" is used to describe this phenomenon in the peripheral nerve. According to previous studies, a prominent nerve containing many axons can be repaired by the multiple regenerating axons sprouting from another nerve that contains fewer axons. Most peripheral nerves contain a mixture of myelinated motor and sensory axons as well as unmyelinated sensory and autonomic axons. In this study, a multiple regeneration animal model was developed by bridging the proximal common peroneal nerve with the distal common peroneal nerve and the tibial nerve. Differences in the multiple regeneration ratio of motor and sensory nerves were evaluated using histomorphometry one month after ablating the dorsal root ganglion (DRGs) and ventral roots, respectively. The results suggest that the motor nerves have a significantly larger multiple regeneration ratio than the sensory nerves at two different time points.     

The experimental study of absorbable chitin conduit for bridging peripheral nerve defect with nerve fasciculu in rats

To investigate the possibility of constructing artificial peripheral nerves using de-acetyl chitin conduit, the sciatic nerves defect model was built at left legs in SD rats. They were divided into 3 groups randomly: group A: nerve graft in situ (n = 12, gap distance 10 mm); group B: biological chitin conduit bridging the peripheral nerve defect (n = 12, gap distance 10 mm); group C: biological chitin conduit bridging the peripheral nerve defect with nerve fibers in conduits (n = 12, gap distance 10 mm). Electrophysiological examination, histological examination and re-myelinated axons counting were applied after 6th and 12th week after operation, respectively. Regenerated nerve fibers were seen in the distal nerve segments of all three groups. The nerve conduction velocity and the re-myelinated axons counting of group A were better than that of group C at both 6th and 12th week time points (p < 0.05). The nerve conduction velocity and the re-myelinated axons counting of group C were better than that of group B at both 6th and 12th week time points (p < 0.05). The repair effects of chitin conduit with nerve fibers in conduit bridging peripheral nerve defect (10 mm) were better than that of simple conduit bridging group, and that of group A (nerve graft group) was better than that of group C.     

Intranasal immunization with autolysin (LytA) in mice model induced protection against five prevalent <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> serotypes in China

In order to evaluate immunogenicity and protective efficacy of LytA from Streptococcus pneumoniae, we subcloned the full-length lytA-encoded autolysin (LytA) from 5 major pathogenic serotype isolates in China and obtained purified rLytA. Bioinformatics analysis showed that sequences of LytA were highly conserved in all strains we used in this work, and western blot analysis demonstrated that rLytAs from heterogeneous serotypes were cross-recognized by serum of mice infected with 23F strain SH137. Mice were intranasally immunized with purified rLytA, and serum anti-rLytA IgG, IgA and secretory IgA were elicited. More importantly, rLytA intranasal-immunized mice showed a significantly higher survival rate and lower bacterial carriage in response to infection by Streptococcus pneumoniae. The fact that mice immunized with rLytA from strain SH137 also had a higher survival rate after intraperitoneal injection of other four serotype strains of living S. pneumoniae suggested that it possessed cross-protection effect. Our study revealed that intranasal immunization with rLytA may protect mice against mucosal and systemic pneumococcal infection; hence, it was an attractive vaccine candidate.     

移植骨髓间充质干细胞肝癌大鼠细胞凋亡及炎症因子的动态变化

BACKGROUND:Bone marrow mesenchymal stem cell transplantation has not been thoroughly reported on its effects on apoptosis in hepatoma carcinoma cells and inflammatory factor level. OBJECTIVE:To investigate the effect of rat bone marrow mesenchymal stem cells on dynamic change of inflammatory factors and cell apoptosis during hepatocarcinogenesis. METHODS:Sixty healthy Sprague-Dawley rats were divided randomly into healthy group (n=30), control group (n=30) and transplantation group (n=30). Healthy group was given ordinary feed and normal water, while other groups were given diethylnitrosamine solution in drinking water to induce liver cancer models. Then, rats in the transplantation group were subjected to bone marrow mesenchymal stem cell transplantation via the tail vein. Two weeks after cell transplantation, CXCL5, interleukin-8 and interleukin-6 levels were tested by ELISA, mRNA level of hepatocyte nuclear factor 1α detected by RT-PCR, expression of Bcl-2 and Bax in liver tissue measured by immunohistochemical method, and liver cancer cell apoptosis index detected by TUNEL technique. RESULTS AND CONCLUSION:After modeling, the expressions of CXCL5, interleukin-8 and interleukin-6 in the control group were significantly higher than those in the healthy group (P < 0.05), while these indexes were reduced significantly after bone marrow mesenchymal stem cell transplantation (P < 0.05) and close to the normal levels (P > 0.05). Bone marrow mesenchymal stem cell transplantation significantly up-regulated the mRNA level of hepatocyte nuclear factor 1α in the liver tissue that was decreased obviously after modeling (P < 0.05). In addition, the expression of Bcl-2 was reduced, while the expression of Bax and the apoptosis index increased significantly in the transplantation group compared with the control group (P < 0.05). These findings indicate that bone marrow mesenchymal stem cell transplantation contributes to hepatocyte differentiation and regeneration in liver cancer rats by reducing serum inflammatory factor levels and promoting apoptosis in hepatoma carcinoma cells.     

Collagen scaffolds modified with CNTF and bFGF promote facial nerve regeneration in minipigs

Most experiments of peripheral nerve repair after injury have been conducted in the rodent model but the translation of findings from rodent studies to clinical practice is needed partly because the nerve regeneration must occur over much longer distances in humans than in rodents. The reconstruction of long distance nerve injuries still represents a great challenge to surgeons who is engaged in peripheral nerve surgery. Here we used the functional nerve conduit (collagen scaffolds incorporated with neurocytokines CNTF and bFGF) to bridge a 35 mm long facial nerve gap in minipig models. At 6 months after surgery, electrophysiology assessment and histological examination were conducted to evaluate the regeneration of peripheral facial nerves. Based on functional and histological observations, the results indicated that the functional collagen scaffolds promoted nerve reconstruction. The number and arrangement of regenerated nerve fibers, myelination, and nerve function reconstruction was better in the CNTF + bFGF conduit group than the single factor CNTF or bFGF conduit group. The functional composite conduit, which exhibited favorable mechanical properties, may promote facial nerve regeneration in minipigs effectively.     

Kinetics of Memory B Cell and Plasma Cell Responses in the Mice Immunized with Plague Vaccines

In our previous studies, we found that plague vaccines can induce long‐term antibody response, but no significant antibody boost was observed when the immunized mice were challenged with virulent Yersinia pestis. However, a booster vaccination of subunit vaccine on week 3 after primary immunization elicited a significantly higher antibody titre than a single dose, whereas no significant antibody titre difference was observed between a single dose and two doses of EV76 vaccination. To address these issues, in this study, we first investigated the kinetics of memory B cells and plasma cells in the mice immunized with EV76 or F1 protein by flow cytometry and then determined antibody titre in five groups of mice immunized with various vaccination strategy. The results showed that memory B cells dropped to a low level at day 56 after primary immunization. In contrast, plasma cells were maintained for more than 98 days. The group with primary immunization of EV76 and booster of F1 antigen developed a higher antibody titre than the group with immunization of F1 antigen and booster of EV76. This result supports a hypothesis that an excess of antigens can neutralize pre‐existing antibodies, and then the redundant antigen induces antibody boost. Taken together, a boost of antibody titre after revaccination may be dependent on the existence of memory B cells and an excess of antigen vaccination. In addition, this study showed an ideal immunization strategy that involves first immunization with a live attenuated vaccine, such as EV76, and then with a subunit vaccine.     

Study on In Vitro Anti-Tumor Activity of Bidens Bipinnata L. Extract

We studied the in vitro anti-tumor activity of Bidens Bipinnata L. extract. MTT assay was used to investigate the inhibitory effect of different concentrations of the extracts on human hepatocellular carcinoma (HepG2) cell lines and human cervical carcinoma (Hela) cell lines, and the IC₅₀ values were calculated. The Bidens Bipinnata L. extract had different degrees of inhibitory effects on these two cells, and when exposure time was 48 h, the inhibition rate reached its peak, with IC₅₀ values of 14.80 µg/mL and 13.50 µg/mL respectively. The Bidens Bipinnata L. extract had a good inhibitory effect on human HepG2 cell lines and Hela cell lines, and thus has certain development prospects.