[Relationship between mRNA expression of MnSOD and manganese neurotoxicity].

OBJECTIVE: To investigate the relationship between mRNA expression of manganese superoxide dismutase (MnSOD) and manganese neurotoxicity. METHODS: Thirty-one patients with occupational chronic manganese poisoning (case group), as well as 31 controls exposed to the same condition (control group), were included in the study. Whole blood RNA was extracted, and the mRNA expression of MnSOD was measured by RT-PCR; the two groups were compared in terms of the mRNA expression of MnSOD. PC12 cells were treated with 0, 100, 200, 400, 600, 800, and 1000 ümol/L MnCl2 for l, 2, 3, and 4 d; the cell viability was determined by MTT assay, and the mRNA expression of MnSOD was measured by RT-PCR. RESULTS: The case group had significantly lower mRNA expression of MnSOD than the control group (0.390 ± 0.080 vs 0.582 ± 0.219, P < 0.05). MnCl2 had a toxic effect on PC12 cells; the concentration of MnCl2 was positively correlated with the toxic effect but negatively correlated with the mRNA expression of MnSOD. CONCLUSION: MnSOD mRNA may be involved in the manganese-induced damage of nerve cells. It is hypothesized that high mRNA expression of MnSOD may play an inhibitory effect on manganese neurotoxicity.

[Experimental study on the therapeutic effect of C-phycocyanin against pulmonary fibrosis induced by paraquat in rats].

OBJECTIVE: To investigate the therapeutic effect of C-phycocyanin (C-PC) from Spirulina platensis on paraquat (PQ)-induced pulmonary fibrosis in rats. METHODS: A total of 90 healthy Wistar rats were randomly and equally divided into normal control group, model group (PQ group), and C-PC treatment group (C-PC group). Each rat in the PQ group and C-PC group were orally administered with a single dose of PQ (50 mg/kg) to establish a rat model of PQ poisoning. Then, the rats in the normal control group and PQ group were orally given saline solution (1 ml/100 g) every day, and the rats in the C-PC group were orally given C-PC (50 mg/kg) every day. Six rats were randomly selected from each group on days 1, 3, 7, 14, and 28. The inferior lobe of each rat's right lung was homogenized for the measurement of hydroxyproline (HYP) and maleic dialdehyde (MDA) levels and superoxide dismutase (SOD) activity. Parts of each rat's left lung were subject to HE staining and Masson staining for pathological observation, and the expression of transforming growth factor-ß(1) (TGF-ß(1)), nuclear factor-kappa B p65 (NF-κB p65), and tumor necrosis factor-α (TNF-α) in lung tissue was measured by immunohistochemistry. RESULTS: The HYP levels on days 1, 3, 7, 14, and 28 and MDA levels on days 14 and 28 were significantly lower in the C-PC group than in the PQ group (P < 0.05, P < 0.01). The SOD activity was significantly higher in the C-PC group than in the PQ group on days 1, 7, 14, and 28 (P < 0.05, P < 0.01). The protein content of TGF-ß(1) and the activities of NF-κB p65 and TNF-α in the PQ group and C-PC group were significantly higher than those in the normal control group, while the indices in the C-PC group were significantly lower than those in the PQ group (P < 0.05, P < 0.01). The pathological observation showed that C-PC could alleviate pulmonary alveolitis and fibrosis in rats with PQ poisoning. CONCLUSION: C-PC can significantly inhibit PQ-induced pulmonary alveolitis and fibrosis in rats.

[Relationship between MnSOD polymorphisms and susceptibility of chronic poisoning exposed to manganism occupationally].

OBJECTIVE: To study the relationship between polymorphisms of MnSOD and the susceptibility of chronic poisoning exposed to manganism occupationally. METHODS: In a study of case-control, genotypes were determined by PCR-RFLP in 164 patients with chronic occupational mangamism poisoning and 328 controls with age- and sex-matched for MnSOD 9Ala-Val. RESULTS: There was a significant difference in the frequency of MnSOD 9Ala-Val at V locus mutant allele between cases and controls (χ(2) = 15.225, P < 0.01, 95%CI = 1.43 ∼ 3.00). Individuals with the genotype VV had a 1.30 of risk increase of occupational chronic manganism poisoning compared with the the genotype AV or AA (OR = 2.30, 95%CI = 1.52 ∼ 3.49, P < 0.05). CONCLUSION: The MnSOD polymorphisms may be related with the susceptibility to chronic occupational manganism poisoning, the risk of chronic occupational manganism poisoning increases in carriers with genotype VV at MnSOD 9Ala-Val locus.

[Clinical trial on standard treatment of acute organophosphorus poisoning].

OBJECTIVE: To explore the norms of treatment of acute organophosphorus pesticide poisoning (AOPP), and observe the curative effect. METHODS: On basis of the pre-research, the norms of treatment of AOPP were summarized, and a multi-center clinical trial was performed in 6 hospitals selected from high incidence of AOPP in Shandong Province. RESULTS: 422 patients of AOPP in 6 hospitals in observation period were treated and observed by the norms of treatment. Among them, the proportion of oral poisoning was 97.16%, middle and severe degree were 87.44%. Compared with themselves 2 years ago before standard treatment, the curative effect of the norms of treatment for AOPP was much better than before. The mortality rate of AOPP declined from 9.87% to 1.66% (Chi2 = 27.92, P < 0.01), that was much better than the average therapeutic effect level of all our province in the same period (the mortality rate: 8.92%) (Chi2 = 26.05, P < 0.01). The average amount of atropine [(37.54 +/- 17.76) mg], dropped greatly [(1280.70 +/- 69.22) mg] (U = 439.22, P < 0.01).The usage of atropine by continuous intravenous injection with venous pump was better than ordinary intravenous injection. The mean dosage of pralidoxime chloride increased twice than the previous (U = 19.48, P < 0.01). There was no drug poisoning. CONCLUSION: The standard treatment of AOPP is urgently needed in our country, especially in rural area. By this trial, the satisfactory effect of the norms of treatment for AOPP summarized is observed and it reduces the fatality rate remarkably.

[Follow-up study on psychic and neuropathic delayed effects of acute organophosphorus pesticides poisoning].

OBJECTIVE: To study the delayed effect on neuropsychopathy and its related factors after acute organophosphorus pesticides poisoning (AOPP). METHODS: Two hundred and fifty-seven cases of AOPP in the observation period were chosen to follow-up 2 months later from the 4 county hospitals in Shandong Province where the incidence of organophosphorus pesticide poisoning is high. RESULTS: Nine cases of organophosphate induced delayed polyneuropathy (OPIDP) were found and the incidence rate was 3.5%. The occurrence of OPIDP were related to the need for emergent artificial respiration, and the degree of poisoning, and the kinds of organophosphorus pesticides (Ops). The positive rate of symptoms of peripheral nerves, central nerves and psychogeny except auditory and visual hallucination after poisoning was significantly higher than that before (P < 0.05). The patient's situation of health, economy and work became statistically worse (P < 0.05). CONCLUSION: We found some had delayed effects on neuropsychopathy after AOPP which could debase the patient's life quality. The control measure should be administered as early as possible.