[Co-occurrence of musculoskeletal disorders and influence factors among Chinese auto workers].

OBJECTIVE: To analyze the prevalence and risk factors of multiple musculoskeletal disorders (MSDs) in auto workers and the associations between MSDs at different sites. METHODS: A cross-sectional survey was conducted in 3998 workers, who were selected from a Chinese auto corporation by cluster random sampling, using the revised Nordic MSDs standard questionnaire; 3800 completed questionnaires were returned. Multinomial logistic regression analysis was performed to assess the risk factors for multiple MSDs. The logbinomial model was used to calculate the prevalence ratios (PRs) of MSDs at different sites and evaluate the associations between MSDs at different sites. RESULTS: Of the 3800 subjects, 2452 (64.5%) had MSDs at two or more sites, and 469 (12.3%) had MSDs at one site. The PRs varied from 1.5 to 6.7, with significant differences among different sites (P < 0.01). Relatively close associations were found between the MSDs at neck and shoulders, back and shoulders/waist, elbows and wrists/hands, waist and neck, wrists/hands and waist, hip and waist, knees and waist, and ankles/feet and elbows. The multinomial logistic regression analysis indicated that the highest risk factor for MSDs was poor posture, including often working in an uncomfortable posture, neck bending forward, and neck twisting (ORs = 3.39, 1.93, and 1.38), followed by labor organization, in which break between tasks could decrease the risk of MSDs at three or more sites to 31%, staff shortage, which could increase the risk of MSDs by 75%, and pushing and pulling heavy objects (> 20 kg) (OR = 1.76). CONCLUSION: Most auto workers with MSDs have multiple sites affected, and there are high associations between the MSDs at different sites. The major risk factors for multiple MSDs in auto workers include poor posture, labor organization, and heavy physical labor.

Safety evaluation of a canine hepatitis DNA vaccine.

DNA vaccines are a novel disease prevention methodology, however their safety has not been well described. We evaluated the safety and efficacy of the DNA vaccine pVAX1-CpG-Loop against infectious canine hepatitis. We demonstrated that pVAX1-CpG-Loop could not be recovered from tissues of vaccinated mice nor from F1 progeny and following vaccination there were no apparent changes in hematologic markers compared to unvaccinated controls. Most important, vaccinated mice were protected from viral challenge. The only detectable effects of the vaccination were elevated AST levels 4 weeks post vaccination and liver lymphocyte infiltration and hydropic degeneration which normalized 6 months later.

[Establishment of B16-HLA-MAGE-3 melanoma cell line coexpressing HLA-A 0201/K(b) and MAGE-3 and its role in tumor vaccine evaluation].

AIM: To establish a tumor model in HLA-A2.1 transgenic mice to examine the efficacy of MAGE-3 vaccine, a cell line coexpressing HLA-A 0201/K(b) and MAGE-3 is established. METHODS: B16-HLA-MAGE-3 melanoma was obtained by means of cotransfection of HLA-A 0201/K(b) and MAGE-3 to B16 melanoma. RT-PCR, FCM analysis and Western blot were used to detect the mRNA or protein of HLA-A 0201/K(b) or MAGE-3 expression in B16-HLA-MAGE-3. The ability of MAGE-3 antigen to be processed and presented in the B16-HLA-MAGE-3 cell line were observed by CTL activity detection and tumor challenge test. RESULTS: Transcription and protein expression of HLA-A 0201/H-2k(b) and MAGE-3 were demonstrated in B16-HLA-MAGE-3 cells. CTL activity of splenocytes in immunized mice against B16-HLA-MAGE-3 was detected and the growth of B16-HLA-MAGE-3 in immunized mice was also inhibited. CONCLUSION: MAGE-3 antigen is able to be processed and presented efficiently by B16-HLA-MAGE-3 melanoma cells and this cell can be employed to test HLA-A2 restricted epitope immunogenicity in the A2-transgenic mice.

[Cohort mortality study of workers in an automobile foundry factory].

OBJECTIVE: To understand the major causes of death in automobile foundry workers and investigate casting manipulations hazards to health. METHODS: A cohort study of 3529 foundry workers registered in one big automobile factory in Shiyan city of China was performed. Standardized mortality ratios (SMRs) were calculated for the main causes of death by using Chinese national mortality rates as reference. RESULTS: The cohort mortality was traced from 1980 to the end of 2005 with an accumulation of 84 999 person-years, revealed 265 deaths. The results of this study showed that the standardized mortality ratio for all subjects was 0.96 (95% CI: 0.85 approximately 1.08), which was very close to that expected on the basis of the China national mortality rates. The SMR increased with age, the SMR became greater than 1 in all groups of age 50 and higher. The results showed that malignant neoplasm (3.43%), accidents (1.16%), cerebro-vascular diseases (1.08%), cardio-vascular diseases (0.79%) were the first four illnesses that threatened workers' life span. Statistically significant mortality of malignant neoplasm (SMR = 7.87), accidents (SMR = 2.70), cardio-vascular diseases (SMR = 2.68) and digestive diseases (SMR = 2.79) were found in the foundry workers. The relative risk of malignant neoplasm for first line workers to assistant workers was 1.99 (P < 0.05). CONCLUSION: The occupational hazards in foundry factory have harmful impact on the workers' health and life span.

[Study on effects of anticancer and immunoregulation of Fuganchun 6 on hepatoma of mouse].

OBJECTIVE: To study the anticancerous effect of Fuganchun 6 (FGC-6) and its immunoregulatory effect on tumor-bearing mice. METHOD: The mice inoculated by H22 cells were divided into 5 groups: model group, 5-Fu group and FGC-6 in high dose, medium dose, and low dose groups. The normal mice were also observed. These mice were treated for 10 days. The weight of tumor mass and mouse were examined. The target-cell-killing activity of NK cells. The proliferation activity of lymphocyte and the production of IL-2 of murine splenocytes were detected respectively. The serum containing FGC-6 was prepared and its inhibition effect on H22 cells was examined by MTT assay and growth curve in vitro. RESULT: Growth of tumor was inhibited markedly by FGC-6 high dose. The inhibition of serum containing FGC-6 on the proliferation of H22 cells in vitro was observerd in a dose and time-dependent manner. The target-cell-killing activity of NK cells and the production of IL-2 of murine splenocytes of model group were lower than those of normal group (P < 0.05). When compared with model group, FGC-6 in high dose elevated the two indexes above-mentioned, and also enhanced the proliferation activity of lymphocyte markedly (P < 0.05). The production of IL-2 of murine splenocytes was also improved when treated by FGC-6 in medium dose (P < 0.05). CONCLUSION: FGC-6 can inhibite the growth of H22 cells markedly and also can strengthen the immunity of H22 transplanted mouse.

[Study on RAPD characteristics of five S180 clonal strains and on biological characteristics of passage cells from S180-S2D9].

OBJECTIVE: To study the random amplified polymorphic DNA (RAPD) characteristics of five S180, clonal cell strains with 23 primers and the biological characteristics of passage cells from S180-S2D9. METHODS: The DNA of 5 clone strains of S180 including S180-S2D9, S180-S2D7, S180-S1F11, S180-S1H10 and S180-S1B11, was amplified with RAPD-PCR using 23 single primers. The PCR products were resolved with electrophoresis on agarose gel. To analyze genomic DNA with RAPD, the cultured cells in vitro were treated with colchicine for 6 hours. Then, the chromosome numbers of 100 cells were examined under the microscope. The KM mice were injected intraperitoneally with 0.2 ml solution of S180-S2D9 cell, and the growth of ascitic fluid and the life span of the mice were observed. The cultured cells were fixed with 750 ml/L ethanol, and DNA analysis was made by Flow Cytometry. RESULTS: Three of the 23 single primers resulted in diversity between amplified products from different clonal strains. RAPD character of S180-S2D9 was analyzed by the 3 single primers; RAPD bands of the first generation, 25th generation, 50th generation and 75th generation showed no difference; ANOVA showed that the average numbers of chromosomes of four generations were of no significant difference (P>0.05). The ascites of the KM mice subjected to the intraperitoneal injection of first generation and 50th generation S180-S2D9 cells was bloody, and the survival days of mice were 13-23 d and 13-20 d respectively; ANOVA showed there was no significant difference between the first generation and 50th generation (P>0.05). DNA contents assayed by flow cytometry revealed that DNA corresponding content of the cells is individually 0.3890, 0.3542, 0.3575 and 0. 3984. These results imply that the S180-S2D9 passage cells have not been found to vary a lot. CONCLUSION: It is adaptable to give quality control to the clonal cell strains with RAPD.

[Preparation of monoclonal antibody against human c-erbB2 and identification of its specificity].

AIM: To prepare monoclonal antibody(mAb) against human c-erbB2 and identify its specificity. METHODS: The epitope of human c-erbB2 antigen was analyzed by using computer software and a immunodominant epitope at the carboxyl-terminal was selected. A peptide consisting of 13 amino acids was synthesized and coupled with keyholelimpet hemocyanin (KLH), and then it was used to immunize BLAB/c mice. The splenocytes of the immunized mice were fused with Sp2/0 cells routinely and the hybridoma cells were selected by HAT selected culture, indirect ELISA, and immunohistochemical staining, and cloned by limiting dilution. The specificity of the mAb was identified by cross-reaction test and blocking test. RESULTS: A hybridoma cell line SC8C1, stably secreting anti-c-erbB2 mAb was obtained. The mAb SC8C1 could react to breast cancer tissue expressing c-erbB2 molecule but did not react to other c-erbB2-negative cells. The mAb will lose the activity after being blocked with synthesized 13 peptide. CONCLUSION: A anti-c-erbB2 mAb SC8C1 is prepared successfully using synthesized 13 peptide as immunogen.

[Influence of exogenous RNA upon expression of mouse albumin gene and its sensitivity to DNase I].

Cultured mouse fibroblasts were treated with rabbit liver RNA. Rat liver RNA was injected into mouse prostates. Influence of exogenous RNA upon expression of mouse albumin gene was detected by immunohistochemical staining. Nucleuses of cultured mouse fibroblasts treated with different RNAs were isolated and digested with DNase I. Mouse albumin gene was amplified by PCR to detect levels of its digestion. It was found that exogenous RNAs could increase the sensitivity of mouse albumin gene to DNase I digestion and promote its expression.