[A meta-analysis of the relationship between overtime work and neck musculoskeletal disorders in Chinese occupational population].

Objective: To systematically evaluate the effect of overtime work on neck musculoskeletal disorders of occupational population in China. Methods: In August 2023, the literatures on the relationship between overtime work and neck musculoskeletal disorders were searched in China National Knowledge Infrasture (CNKI), WanFang Database, Chinese Science & Technology Journal Database (VIP), China Biomedical Literature Service System (SinoMed) and PubMed. The search scope was Chinese and English literatures published before June 30, 2023. The Quality of literature studies was evaluated using the Agency for Healthcare Research and Quality (AHRQ) cross-sectional study quality evaluation criteria. The Stata 15.0 software was used to calculate combined OR values, and subgroup analysis and meta regression were used to explore the sources of heterogeneity. Results: A total of 32 literatures were included, all of which were in Chinese, with a total sample size of 36003 people, and the literature quality scores were 5-7 points. Heterogeneity test showed that there was no heterogeneity between the literatures (I(2)=20.3%, P=0.156), so fixed effect model was selected to calculate the combined OR value. The combined OR value of overtime work on neck musculoskeletal disorders was 1.51 (95%CI: 1.42-1.60, P<0.001). Subgroup analysis showed that the combined OR of occupational population <35 years old group was higher than that in the ≥35 years old group (P<0.05). But there were no significant differences in the combined OR values in the subgroups classified by average years of service, male proportion, type of OR values, sample size and industry classification (P>0.05) . Conclusion: Overtime work is a risk factor for neck musculoskeletal disorders in Chinese occupational population. Working hours should be rationally arranged to reduce the prevalence of neck musculoskeletal disorders.

[Effects of individual factors and labor organization on neck pain in auto assembler].

Objective: To investigate the influence of individual factors and labor organization on the prevalence of neck pain (hereinafter referred to as neck pain) in automotive assemblers, and to provide a basis for enterprises to optimize neck pain interventions. Methods: A cluster random sampling method was taken in January 2021, at an automobile manufacturing plant in Shiyan, 656 assemblers with ≥1.0 years of service were selected, the "Musculoskeletal Disorder Questionnaire" was used to investigate the incidence and influencing factors of neck pain. Pearson χ(2) test or trend χ(2) test was used to compare the data rates. The influencing factors of neck pain were analyzed by multivariate logistic regression. Results: The prevalence rate of neck pain (hereinafter referred to as the prevalence rate of neck pain) of automobile assemblers within one year was 53.94% (342/634) . The prevalence of neck pain in women was higher than that in men (69.1% vs 48.6%, P<0.01) . The prevalence of neck pain was related to length of service, self-assessment of fatigue, working hours per week, working in the same workshop, rest days per shift, and accumulated rest time per shift (P<0.05) . Multivariate logistic regression analysis showed that the risk of neck pain in women was 2.434 times higher than that in men; The risk of neck pain increased by 18.9% for each hour of work per week; Rest during work was a protective factor for neck pain. The number of rest per shift increased and the risk of neck pain decreased (r=0.405, 0.311, 0.302, 95%CI=0.205~0.803, 0.169~0.572, 0.142~0.642, P<0.05) . Conclusion: The annual prevalence of neck pain was higher in automobile assemblers. Enterprises should fully consider the influencing factors such as gender, working hours per week and the number of breaks when arranging production.

[Influencing factors of no seeking medical treatment among pneumoconiosis patients].

Objective: To study the causes and influencing factors of no seeking medical treatment among pneumoconiosis patients. Methods: Using stratified sampling method and typical survey method, we carried out the questionnaire survey in nine provinces in China including the east, the medium and the western region using a questionnaire on the seeking medical behavior pf pneumoconiosis patients and the influencing factors. The subjects include occupational pneumoconiosis cases and clinically diagnosed cases and the response rate is 94.3 percent. The data was entered twice with epidate3.1 and error detection and statistical analysis was completed with SPSS 20.0. Chi-square test was used for univariate analysis, and multivariate logistic regression was used for multivariate analysis. Results: One thousand and thirty-seven subjects were investigated with average age 55.9±11.2 years. Seventy percent of them were silicosis and 21.9 percent were coal worker's pneumoconiosis with 67.5 percent of them residing permanently in the countryside, and 37.9 percent of their education background were primary school culture and 33.1 percent of them had junior high school culture. Thirty two point six percent of respondents had no personal income with a median monthly income of 1 200 yuan. Four hundred and thirty four of subjects hadn't seek medical treatment since they got the pneumoconiosis accounting for 41.9 percent with three hundred and thirty seven of them hospitalized directly. The reasons of no seeking medical treatment for the respondents mainly include the self-induction symptoms lighter, the high cost of treatment and cannot claiming the payment of the medical expenses, buying drugs in drugstore, thinking that no medicine can cure pneumoconiosis or no effect, complex procedures, too far away from medical institutions, no unaccompanied, needing a long time or no time, communication disorders, etc. accounting for 44.4 percent, 24.6 percent, 10.9 percent, 9.1 percent, 6.9 percent, 4.4percent, 3.2 percent, 2.9 percent, 1.9 percent, 1.5 percent, respectively. The results of multivariate analysis showed the main characteristics of subjects with restrictions to the outpatient health service utilization are as follows: demographic sociological indicators such as registered permanent residence area is western (OR(western)=2.18, 95%CI:1.38-3.43) , more than seventy five years old (OR(over 75)=6.82, 95%CI:2.04-22.9) , unemployment, temporary or permanent employment (OR (unemployment)=1.90, 95%CI:1.17-3.08; OR(temporary employment)=3.11, 95%CI:1.57-6.14; OR(permanent employment)=2.10, 95%CI:1.18-3.74) , self-rated health score of 50 or above (OR(self-rated-70)=2.04, 95%CI:1.18-3.51; OR(self-rated-90)=3.00, 95%CI:1.97-5.37; OR(self-rated 90)=2.95, 95%CI:1.74-8.07) ; with increase to the outpatient health service utilization are breath with difficulty (OR=0.57, 95%CI:0.41-0.78) , emphysema (OR=0.48, 95%CI:0.26-0.90) , hospitalized with pneumo-coniosis (OR=0.12, 95%CI:0.07-0.20) . Conclusion: Pneumoconiosis patients no covered by injury insurance should be orderly included in the basic medical security system, and be given the medical treatment actively; It should be strengthened the health management for the pneumoconiosis patients and correctly guided the utilization of medical services.

Physico-chemical properties of recombinant desulphatohirudin.

Physico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies.

Kinetic studies of plasminogen activation by epithelial tissue plasminogen activator.

Initial-rate kinetic studies of the activation of plasminogen by epithelial activator were performed in the absence and in the presence of fibrinogen and CNBr-digested fibrinogen, under assay conditions similar to those described by Hoylaerts et al. (J Biol Chem, 257, 2912, 1982). In the purified system, and in the absence of any stimulator, Lys-plasminogen is more readily activated than Glu-plasminogen, with catalytic rate constants of 0.01 s-1 and 0.0034 s-1 and Michaelis constants of 1.2 microM respectively. With Glu-plasminogen, double reciprocal plots deviated from linearity at low concentrations of plasminogen, in agreement with the findings reported for melanoma activator. In the presence of fibrinogen, activation rates for both Lys and Glu-plasminogen were increased. (kcat = 0.017 and 0.041 s-1 and km = 1.4 and 41 microM, respectively). In the presence of CNBr-fragments of fibrinogen, the Michaelis constant is lowered for both forms of plasminogen, (km = 0.3 microM) thus indicating high affinity and efficient activation of plasminogen on fibrin clot. Comparison of the kinetic data with those reported for melanoma activator suggest that even though the values of the kinetic constants are different, epithelial activator has a similar mechanism of action for the activation of plasminogen as the melanoma enzyme.

In vitro studies on the fibrinolytic, thrombolytic and fibrinogenolytic properties of a tissue plasminogen activator from guinea pig keratocytes.

The fibrinolytic and thrombolytic properties of a tissue plasminogen activator (tPA) purified from the conditioned medium of an established guinea pig keratocyte (GPK) cell line were investigated in in vitro systems and compared with urokinase. Using the fibrin clot lysis assay, GPK activator appears to be similar to human melanoma tPA and not to human urokinase. GPK activator also caused negligible fibrinogen breakdown, when incubated with human plasma at 37 degrees C over 23 hr. Urokinase on the other hand caused significant fibrinogenolysis, under similar conditions. Comparison of the lysis of plasma clots by GPK activator and human urokinase have shown that GPK activator was a much more effective fibrinolytic agent than urokinase, especially at lower concentrations (less than 50 IU/ml). Studies on the thrombolytic effect of GPK activator on the lysis of aged and cross-linked whole human blood clots and plasma clots hanging in artificially circulating human plasma suggest that GPK activator can lyse both these types of clots equally well. The lysis is dose dependent, attaining complete lysis within 3-6 hr with the concentration of GPK activator in the range of 1-5 micrograms/ml plasma. It is concluded that GPK activator has a higher fibrinolytic and thrombolytic activity and lower fibrinogenolytic activity than urokinase.