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Human activities, especially industrial production, have aggravated the pollution of heavy metals in the environment, and especially after disrupting the food chain, such pollution can cause varying degrees of heavy metal poisoning in human beings. Studies have shown that exposure to heavy metals tends to upset the balance of the flora and further aggravate organ toxicity. Intestinal probiotics represented by Lactobacillus can actively adsorb heavy metal ions, promote their excretion, and reduce their induced oxidative stress injury and inflammatory response. Focusing on the chronic toxicity induced by long-term low-dose exposure to heavy metals, this article reviewed current pollution status of several common heavy metals (lead, cadmium, and mercury), analyzed the interaction between heavy metals, intestinal flora, and probiotics, and summarized proposed mechanisms of probiotics in mitigating chronic heavy metal toxicity, aiming to provide new ideas for effective prevention and treatment of organ toxicity induced by heavy metals.
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OBJECTIVE To investigate the effect of cadmium (Cd) exposure in vivo and in vitro on duodenal epithelial cells in mice and the mechanism. METHODS In vivo, C57BL/6 mice were ig administered with CdCI210 mg-kg" once per day for 30 d to establish a chronic cadmium poisoning model, or were ig administered with a single dose of CdCh 80 mg • kg-1 to establish an acute cadmium poisoning model before the survival status and survival rate of mice were observed. Duodenal epithelial cells of acute and chronic cadmium poisoning mice were isolated and cultured. The cells were identified as epithelial cells by E-cadherin immunofluorescence. Then, the content of cadmium ion in duodenal epithelial cells was detected by confocal laser microscopy. In vitro, duodenal epithelial cells of normal C57BL/6 mice were isolated and cultured, and incubated with CdCI2 2.5-100 pmol-L-1 for 24 h. CellTiter-Blue was used to detect cell viability. Subsequently, the duodenal epithelial cells of normal mice were incubated with CdCI215 Mmol • L-1 for 24 h, and cell cycle was detected by flow cytometry. Then, the duodenal epithelial cells of normal C57BL76 mice were incubated with CdCI230 Mmol-L'1 for 3-12 h and the expression of cleaved-caspase 3 was detected by Western blotting. RESULTS Compared with the control group, the activities of mice with chronic cadmium poisoning were all normal. The mice with acute cadmium poisoning showed depression, less food intake and death. At the 5th day of acute cadmium exposure, the survival rate of mice decreased to 40%. The content of cadmium ion in duodenal epithelial cells of acute and chronic cadmium poisoning mice increased significantly (F<0.01). Furthermore, CdCI2 inhibited the viability of duodenal epithelial cells cultured in vitro and the half inhibitory concentration (IC50) was (24.55±0.84) pmol-L-1. Compared with the control group, CdCI2 blocked the cell cycle of duodenal epithelial cells at Go/G, phase (P<0.05), and the expression of cleaved-caspase 3 in duodenal epithelial cells was significantly increased after CdCI2 treatment for 6, 9 and 12 h (P<0.05, P<0.01). CONCLUSION Cadmium that enters the body through the digestive tract can be absorbed by duodenal epithelial cells and cause damage to the cells. The mechanism of cadmium-induced damage may be related to cell cycle arrest and caspase 3-mediated apoptosis.
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OBJECTIVE: To analyze the epidemiological characteristics and predict epidemiological trends of occupational chemical poisoning,based on directly reported data during 2006-2015 in Guangdong Province. METHODS: The data of patients with occupational chemical poisoning reported from National Information Surveillance System for Occupational Disease and Occupational Health from 2006 to 2015 in Guangdong Province were collected. The epidemiological characteristics were retrospectively analyzed. The autoregressive integral moving average model( ARIMA model) was established and validated based on the number of the new onset cases and was used to predict the trends of occupational chemical poisoning from 2017 to 2020 in Guangdong Province. RESULTS: From 2006 to 2015,1 288 new cases of occupational chemical poisoning were reported in Guangdong Province,which accounted for 24. 4% of the total number of new cases of occupational diseases in the province( 5 283 cases). Among the new cases,the percentage of acute and chronic poisoning was 21. 7%( 279/1 288) and 78. 3%( 1 009/1 288). There was 74. 7%( 962/1 288) of organic solvent poisoning. Five kinds of new occupational chemical poisoning were found. Most of the new cases were male,accounting for 56. 7%( 729/1 288). They were mainly distributed and concentrated in Pearl River Delta Region,accounting for 95. 9%(1 235/1 288). Shenzhen,Dongguan and Guangzhou were the most three cities which had 425,325 and 209 cases respectively,all of them accounted for 74. 4%( 959/1 288). The new cases of poisoning mainly distributed in medium and small enterprises( 72. 0%),private economic enterprises( 50. 9%) and manufacturing industries(70. 5%). The number of occupational chemical poisoning diseases decreased first,and increased,and the proportion to the total number of occupational diseases in Guangdong Province showed a straight downward trend(P < 0. 01). The median age at diagnosis was 35 years old and the median work year at diagnosis was 2. 0 years,and both of them showed an increasing trend( P < 0. 01). CONCLUSION: Occupational chemical poisoning in Guangdong Province has certain characteristic of crowd aggregation and epidemic trends.
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OBJECTIVE: To analyze the clinical characteristics of atypical occupational chronic mercury poisoning cases and explore ways to avoid misdiagnosis. METHODS: The clinical data of 2 atypical occupational chronic mercury poisoning cases were retrospectively analyzed. RESULTS: The two cases were in the same instrument factory. They were engaged in the inspection and filling of thermometers, with a long history of occupational mercury exposure. The main clinical manifestations were the nervous system damage. In the two cases,one case showed severe pain in limbs and joints accompanied with neurasthenia syndrome, oral-gingivitis and increased urine mercury; while the other one showed Parkinson's syndrome-like involuntary tremor whenever at rest or activity accompanied with neurasthenic syndrome and increased urine mercury,without oral-gingivitis. The physical examination showed notable finger tremor,tongue tremor,and eyelid tremor,and one case had coarse tremor of upper limb. Both cases were diagnosed as occupational chronic mercury poisoning. CONCLUSION: The nervous system is the most common site of involvement of patients with occupational chronic mercury poisoning,whose clinical manifestations are diverse. Clinicians should raise awareness of mercury poisoning,consult medical history in detail and reduce misdiagnosis.
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OBJECTIVE: To evaluate the therapeutic effects between comprehensive therapy and routine therapy in treatment of occupational chronic n-hexane poisoning. METHODS: By randomized controlled trial,116 cases with occupational chronic n-hexane poisoning were divided into two groups: the control group( n = 58) and the treatment group( n = 58). Subjects in the control group were given vitamin B_(12) and vitamin B_1 for neural nutrition; and Danshen and deproteinized calf blood extractive injection for activating blood circulation to dissipate blood stasis. Subjects in the treatment group were treated with comprehensive treatment including traditional Chinese and Western medicine,which including mouse nerve growth factor,acupuncture,physical therapy( infraredtherapy,microwave irradiation therapy),Chinese medicine steamingwashing and comprehensive rehabilitation therapy for a period of 12 weeks in addition to the conventional treatment. The curative effect and adverse reactions of both groups were observed after 12 weeks,and the treatment results and hospital stay were followed up. RESULTS: Before treatment,no significant differences( P > 0. 05) were noted in both groups in scores of neurological symptoms,signs,activities of daily living and neurogenic damage indexes of electroneuromyography[including motor digital latency( MDL),motor nerve conduction velocity( MCV),sense nerve conduction velocity( SCV) of median nerve,ulnar nerve,sural nerve or common peroneal nerve; and the detection of lengthen MDL,shorten MCV and SCV]. After treatment,patients in both groups got better in terms of the above indicators( P < 0. 05),with larger extend of improvement noted in the treatment group than in the control group( P < 0. 05). No obvious adverse reactions were noted in the 2 groups. Hospital stay of patients in the treatment group was about 2 months shorter than that in the control group( P < 0. 05). CONCLUSION: The therapeutic effects of comprehensive therapy on occupational chronic n-hexane poisoning are obviously better than routine therapy,which is an effective and safe therapeutic method.
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Aim The chronic toxicity of tea polyphenols(TP) in dogs was observed. Methods 18 dogs were randomly divided into high, middle and low dose TP groups and one control group . When TP was given(po) by 650 mg?kg-1?d-1,65 mg?kg-1?d-1,6.5 mg?kg-1?d-1 respectively for 90 d and after TP was stopped for two weeks, the general conditions, ECG, blood routine, urine routine, serum lipids, blood sugar, coagulation time, and hepatic and kidney function were detected respectively. Results These mdices were not different from each other among the 4 groups before, during and after administration of TP . The level of serum total cholesterol was progressively decreased in TP groups. Conclusion TP has no toxic effect on dogs and can decrease the level of serum total cholesterol in normal dogs.