Welding Work On The Workers' Neurobehavioral And Neurotransmitter

Ⅰ. Object and methodWelding is a main approach for professional workers exposed to manganese. Manganese is an essential trace element in the healthy body. It is the actived component and cofactor of much enzyme. It also can active some enzyme, and take part in many biochemical reactions. However, exposure to too much manganese can lead to manganese intoxication. Manganese intoxication mainly impairs nervous system, especially of extrapyramidal malfunction, and accompanys with psychic symptom.The toxicity of manganese has been known more than one hundred years, but we know only a little about primeval examination of neural toxicity of manganese and mechanism of its toxicity. Now, with the improvement of productive environment, most of developed countries and some developing countries including our country have controlled manganese intoxication on some degree. But the chronic effects that are leaded by the low level and long time exposure to manganese are becoming protrusive now increasingly. Behavioral index is a better index of detecting and reflecting subclinical impairment of central nervous system according to the level of the science at present. Neurobehavioral test has the advantage of simplicity and no wound and good sensitivity, now it is mostly used to detect the primeval impairment of the workers exposed to manganese. Because of difference among formations and conditions of the tests and explanations of examiners, the results of different researchers are often difficult to compare with. Since Baker developed computerized neurobehavioral evaluations system, the neurobehavioral test has become roboticized and normative and the result can be recorded and saved automatically, ant it improves the reliability and validity and comparison.The computerized neurobehavioral evaluations system (Chinese version, NES-C3), compiled by medical college of fudan university, is used in our study. It includes 21 subtests. We try to select 8 sensitive subtests to test. 91 manganese-exposed welding workers and 49 non-exposed workers are chosen as subjects. Each worker is tested by a professional person.The toxicity mechanism of manganese is not explicated completely today. The research try to explore the toxicity mechanism through the test of serum NE, ACHE, NOS and blood essential element of the welding workers. Draw 4ml blood from the vein of elbow, put 0.5ml blood into EP tubes with anticoagulant, use mixed acid to digest the blood, then the content of blood manganese, zinc, copper, iron, magnesium and calcium is determined by graphite stove atomic absorption method. The content of serum NE is determined by ELISA method. The activity of serum ACHE is determined by spectronmetric method. The activity of NOS isdetermined by NOS catalyzed L-Arg method.All the statistical analysis is done in SAS8.1 with the computer.II. Resultl.The welding workers changed significantly comparing with the control workers in digit symbol, simple visual reaction time, choice visual reaction time, pursuit aiming and tension, fatigue, vigor in POMS (P<0.05 or P<0.01).2. The content of NE and activity of ACHE in welding workers are much higher than that in the control (P<0.01).3. The contents of blood manganese and magnesium in welding workers are much higher than that in the control (P<0.01orP<0.05). The content of blood zinc in welding workers is much lower than that in the control (P<0.05). There is no significant difference in contents of blood copper, iron and calcium. The activity of NOS and iNOS in welding workers is much lower than that in the control (P<0.05).4. Multivariate analysis shows that neither of the employment duration and tested results is associated with the content of blood manganese (P>0.05).III. Conclusionl.The results of mood states, digit symbol, pursuit aiming, simple visual reaction time and choice visual reaction time testing are corresponding with traditional test by hand, and these subtests are sensitive. The difference is not significant about the subtests reflecting memory function. The reason is that the subtest reflecting memory function is less sensitive than other subtests, and it should be proved in future. From this study, we find that we can select some subtests to evaluate the effect of welding on central nervous system of workers.2.NE is a neurotransmitter. Some research shows that the content of NE in the cerebrum of the manganese-exposed rat increases at early stage. And our study also finds this difference of serum NE is significant between welding workers and the control. It finds that the welding can make NE change, and then neurobehavioral function is changed correspondingly.3.ACH is an important neurotransmitter in outer and center nervous system, and it plays a very important role in study and memory. ACHE can hydrolyze ACH, then make ACH lose activity. And our study finds the activity of ACHE in welding workers is much higher than that in the control. It proves that the welding can make the content of ACH decrease through ACHE, and then affects the study and memory.4.NO is a cellular message molecule, and it plays a very important role as the second message and neurotransmitter. The synthesis of NO is made by NOS catalyzing L-Arg. Thestudy finds that the bioactivity of serum NOS of welding workers is much lower than that in the control. Some research shows that manganese can make the essential element in the cerebrum change. And our study also finds the difference of essential element in the blood is significant between welding workers and the control. It finds that the welding can make NOS and the essential element change, and then neurobehavioral function is changed correspondingly.5.The content of blood manganese in welding workers is much higher than that in the control, but the content of blood manganese doesn't consider as the body burden of manganese.