Effects of different light on the ethology and melatonin secretion in depressive rats / 中国职业医学

OBJECTIVE: To observe the impact of energy saving light,incandescent light and circadian light on the ethology of depressive rats and explore its possible mechanism on affecting the secretion of melatonin. METHODS: Thirty rats aged 6weeks were randomly selected from 40 specific pathogen free health female SD rats after they adapted to the living environment,depressive rat models were established in the rats by bilateral ovariectomy combined with isolated living and chronic unpredictable mild stress stimulation at the age of 11-14 weeks. Then these 30 ovariectomized rats were randomly divided into 3 intervention groups,including an energy saving light group,an incandescent light group and a circadian light group,with 10 rats in each group. The rats in these 3 groups were given specific experimental light intervention for 3 weeks respectively at the age of 17 weeks. The other 10 rats were raised in conventional environment as the control group. Their body weights were measured at the age of 17,19,20 and 21 weeks. The ethology tests were carried out by sucrose preference test and the open-field test at the age of 7,14 and 20 weeks respectively. The melatonin levels in peripheral blood of 7 time points from 19: 30 to 8: 30 were measured in the rats at age of 21 weeks. One rat in each group at every time point was randomly selected for examination. RESULTS: At the age of 17 weeks before light-intervention,the body weights of rats in 4 groups showed no significant difference( P > 0. 05). After light-intervention,at the age of 17-20 weeks,the body weights of rats in 3 intervention groups were gradually increased with the increase of age( P < 0. 05).There was no significant difference between body weights of rats at the age of 21 weeks and those at the age of 20 weeks in each group( P > 0. 05). At age of 7 weeks,no significant differences were found in sucrose consumption and standing scores among these 4 groups( P > 0. 05). After the depressive models were established,at the age of 14 weeks before light-intervention,in rats of these 3 intervention groups,the sucrose consumption and standing scores were lower than those of the control group( P < 0. 05),and there was no significant difference found in the above 2 indexes among these 3intervention groups( P > 0. 05). At the age of 20 weeks after light-intervention,the sucrose consumption and standing scores were not significantly different from each other among the 4 groups( P > 0. 05). The peak levels of melatonin in the peripheral blood of rats in these 3 intervention groups were higher than that in the control group. The peak levels onsets of melatonin in peripheral blood of rats in the circadian light group and the energy saving light group were earlier or 2 hours delayed compared to that of control group,while it was similar between the incandescent light group and control group.CONCLUSION: The circadian light,the energy saving light and the incandescent light are similarly effective in improving the behaviors of depressive rats. The circadian light can delay the onset of peak level of melatonin in peripheral blood.

Characteristics of infrasound and its influence on workers in working environment of certain thermoelectricity works and department / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the characteristics of infrasound and its effects on the workers at power plants.</p><p><b>METHODS</b>The audible noise and infrasound in three thermoelectricity plants were measured and by using Symptom Checklist 90 (SCL-90), the subjective sensation, and the physiological indices were compared between exposed workers and controls.</p><p><b>RESULTS</b>The infrasound levels were different at different measure sites of the three thermoelectricity works ranging from 40 to 98 dB. There was still 40 approximately 80 dB infrasound even when the soot blower stopped running. Different apparatus produced different infrasound levels with the highest ranging from 62 to 115 dB. A single frequency (16 Hz) infrasound was produced in certain department during working hour with sound pressure levels of 110 to 120 dB, but the audible noise sound pressure level was less than 70 dB. There was no significant difference in the indices representing vision fatigue and neurobehaviour function between exposed workers and controls. Workers at certain department experienced evident subjective sensation of neurobehavioral dysfunction, and the scores of somatization, depression, hostility, phobic anxiety, and psychotism in the SCL-90 were significantly higher in the exposed group than in the control and the norm in China (P < 0.05).</p><p><b>CONCLUSION</b>Infrasound is ubiquitous in the working environment, but usually, the noise levels are less than 120 dB. In some special production department, there is persistent infrasound above 110 to 120 dB. No obvious health effects are found among those who are exposed to infrasound below 100 dB. However, the workers who are chronically exposed to infrasound above 110 to 120 dB present notable subjective sensation of autonomic neurobehavioral dysfunction, and their psychological health status is not as good as those in the control and those in the domestic normal pattern.</p>

Investigation on mental health of residents living in a mineral area in Hubei province / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effect of mining operations on the mental health of residents living in a mining area in Hubei province.</p><p><b>METHODS</b>Villagers (n = 93) living in the mining area were compared with a control group of residents (n = 101) in mental health status, and knowledge of environment and health. The mental health status of villagers was assessed using the Symptom Checklist 90 (SCL-90), State-Trait Anxiety Inventory (STAI); The knowledge of environment and health was evaluated using a self-designed questionnaire. The urine and hair samples were collected from some subjects. The lead, cadmium, arsenic, copper and zinc contents were detected as well as the total protein, NAG, d-ALA in the urine.</p><p><b>RESULTS</b>The occurrence rate of lead, cadmium, arsenic exposure symptoms was significantly higher in the exposed group than in the control group. The urine cadmium, the hair cadmium, the hair arsenic and hair lead were significantly higher in the exposed group than in the control group (P < 0.05). The positive symptom detection rate of SCL-90 in the exposed group was 8.60% compared with 0.99% of the control group. For the SCL-90, the total scale, somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, paranoid ideation, psychoticism, other symptom in the exposed groups were significantly higher than those in the control group (P < 0.05), indicating the status of the psychological hygiene of the exposed group was worse than the control group. The total S-AI (anxiety) score and the sex-specific value in the exposed group were higher than the control group (P < 0.05, P < 0.01), which showed that the anxiety of the exposed group was more evident. The total T-AI score and the sex-specific value in women of the exposed group were significantly higher than the control group (P < 0.01), showing that the anxiety were more significant in the exposed group, especially the women of the exposed group.</p><p><b>CONCLUSION</b>The mental health status of the residents who living in a mining area is affected and they have a higher S-AI and T-AI scale than those living a non-mining area.</p>

Effects of infrasound on activities of 3beta hydroxysteroid dehydrogenase and acid phosphatase of polygonal cells in adrenal cortex zona fasciculate in mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the biological effects of infrasound on the polygonal cells in adrenal cortex zona fasciculation in mice.</p><p><b>METHODS</b>The biological effects of infrasound on the activities of 3beta hydroxysteroid dehydrogenase (3-betaHSDH) and acid phosphatase(ACP) of the polygonal cells in adrenal cortex zona fasciculate were observed when exposure to 8 and 16 Hz infrasound at 80, 90, 100, 110, 120 and 130 dB for 1 day, 7 days and 14 days or 14 days after the exposure.</p><p><b>RESULTS</b>When exposure to 8 Hz infrasound, the enzyme activities of 3-betaHSDH increase as the sound pressure levels increase. Only when the sound pressure levels reach 130 dB, the enzyme activities began to decrease exceptionally. When exposure to 16 Hz, 80 dB infrasound, no significant difference between the treatment and control group in the activities of 3-betaHSDH could be observed, but the injury of the polygonal cells had appeared. When exposure to 16 Hz, 100 dB infrasound, the activities of 3-betaHSDH started to increase. The cell injury still existed. When exposed to 16 Hz, 120 dB infrasound, the local tissue damage represented. Fourteen days after the mice exposure to 8 Hz, 90 dB and 130 dB infrasound for 14 days continuously, the local tissue injury of the adrenal cortex zona fasciculation began to recover at certain extent, but the higher the exposure sound pressure level, the poorer the tissue recovery.</p><p><b>CONCLUSION</b>The biological effects of infrasound on the polygonal cells in adrenal cortex zona fasciculation response to the frequency of the infrasound are found at certain action strength range, but this characteristic usually is covered by the severe tissue injury. When exposure to infrasound is stopped for a period of time, the local tissue injury of the adrenal cortex zona fasciculation could recovers at certain extent, but the higher the exposure sound pressure level, the more poorer the tissue recovery.</p>

Study on the psychosocial status and related factors in three universities during severe acute respiratory syndrome epidemic in Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the psychosocial status and related factors among university students during severe acute respiratory syndrome (SARS) epidemic in Beijing.</p><p><b>METHODS</b>By means of stratified cluster sampling, symptom checklist-90 (SCL-90) and questionnaire on general information were applied among 6800 students in three universities in Beijing.</p><p><b>RESULTS</b>There were 6280 valid questionnaires gathered. In order to control and prevent SARS, strict management was conducted in three universities which providing various social supports. Out of the 6280 students, 460 had SCL-90 positive symptoms with a rate of 7.3%. Risk factors of SCL-90 positive symptom were found as follows: major in arts (OR = 2.00), misconception on the control and prevention of SARS (OR = 1.91), considering measures non-effective (OR = 2.25), and do not believe that SARS can be under control (OR = 3.57). Protective factors of SCL-90 positive symptom would include as: being female (OR = 0.77), being graduate students (OR = 0.38), and being not much influenced on study and daily life during the period of strict management (OR = 0.54).</p><p><b>CONCLUSION</b>Psychosocial status of students was influenced by their knowledge and attitude on SARS. Various social supports might keep the university students to having a healthy psychosocial status.</p>