In vitro evaluation of cutaneous allergic reaction induced by chemicals using dendritic cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the use of dendritic cells derived from mice bone marrow to evaluate the cutaneous allergic reaction induced by chemical sensitizers.</p><p><b>METHODS</b>Dendritic cells derived from mice bone marrow were cultured and administrated with 2, 4-dinitrochlorobenzene (DNCB), nickel sulfate (NiSO4), sodium dodecyl sulfate (SDS) and hexyl cinnamic aldehyde (HCA), respectively. Cell membrane molecule CD86 and extracellular IL-1 beta, IL-6 and IL-12 were detected after 0, 1, 6, 12, 24, 36, 48 hour's administration, respectively.</p><p><b>RESULTS</b>CD86 expression reached the highest level after exposure to DNCB for 48 h, and increased by about 279% compared with the control (P < 0.05), while it was lower than that of control after administrated with NiSO4 and HCA for 1 h and 6 h, and SDS for 36 h, respectively (P < 0.05). Extracellular IL-1 beta increased greatly after exposure to NiSO4 just for 1 h, with the maximum at 48 h (298 pg/ml, P < 0.05), and after exposure to HCA for 6 h, with maximum at 48 h (84 pg/ml, P < 0.05). However, it didn't fluctuate significantly after administrated with DNCB and SDS respectively, compared with the control. Extracellular IL-6 increased significantly after exposure to NiSO4 for 1 h, with the maximum at 24 h (2152 pg/ml, P < 0.05). After exposure to HCA, extracellular IL-6 reached the maximum at 1 h (1403 pg/ml), and then it was decreased quickly, but still higher than the control (P < 0.05), while it didn't change significantly after treatment with DNCB and SDS, compared with the control (P > 0.05). Extracellular IL-12 was not detected out among all the groups.</p><p><b>CONCLUSION</b>Chemical sensitizer DNCB could induce the high expression of CD86 on DC membrane, and NiSO4 and HCA could induce DC to release IL-1 beta and IL-6. However, the irritant SDS had no such effect.</p>

Effects of occupational lead exposure on bone mineral density and bone metabolism in workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of occupational lead exposure on the bone mineral density and the bone metabolism in exposed workers.</p><p><b>METHODS</b>Two hundred and ninety-eight lead-exposed workers in a storage battery plant in Shanghai were selected as the exposed subjects while eighty-one healthy officers in the plant who were not occupationally exposed to lead were treated as the control. The blood lead (BPb) and the urinary lead (UPb) were used as the exposure biomarkers while the Z score, the urinary hydroxyproline (HYP) the serum alkaline phosphatase (ALP) the serum alkaline phosphatase bone isoenzyme BALP and the serum osteocalcin BGP were used as the effect biomarkers for the bone effect caused by the lead. Bone mineral density (BMD) was measured by the single-photon absorptiometry (SPA-4).</p><p><b>RESULTS</b>The BPb, UPb, HYP, ALP, BALP in the occupational lead exposure group were higher than those in the control group with significantly statistical difference in male (P < 0.01). The levels of BGP in the exposure group was higher than that in the control group without significantly statistical difference (P > 0.05). The BMD in the exposure group was lower than that in the control group without significantly statistical difference (P > 0.05). The BMD was significantly decreased in the groups of the UPb 10 approximately microg/g Cr level compared with the 0 approximately microg/g Cr group with the significant difference (P < 0.01). In males, the BMD was significantly decreased in the group of the BPb 300 approximately microg/L level compared with the 0 approximately microg/L group with the significant difference (P < 0.01). The levels of HYP, ALP, BALP, BGP in the UPb 20 approximately microg/g Cr group were significantly higher than those in the UPb 0 approximately microg/g Cr group (P < 0.05). The levels of HYP, ALP, BALP, BGP in the BPb 300 approximately microg/L group were significantly higher than those in the BPb 0 approximately microg/L group (P < 0.05). The prevalence of both osteoporosis and the abnormal bone metabolisms indexes would increase significantly with the increase of the lead exposure (P < 0.01) with the linear correlation (P < 0.01). But the prevalence of higher BGP had no significant correlation with UPb (P > 0.05). BMDs were calculated using BMDS Version 1.3.2 software and BMDLs were also determined. The BMDLs of BPb and UPb for lead-induced osteoporosis were higher than those representing the change of bone metabolism induced by lead.</p><p><b>CONCLUSIONS</b>The occupational exposure to lead could cause the decrease of the bone mineral density, lead to the osteoporosis, and may affect the bone metabolism.</p>

Intervention of nicotinamide on skin melanin genesis after UVA exposed / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the interference effect of nicotinamide on UVA-induced melanin genesis and melanin transport in human skin melanocyte.</p><p><b>METHODS</b>The optimum UVA dose expected to cause cell proliferation: 0.2 J/cm(2), nicotinamide was added immediately after the 0.2 J/cm(2) UVA exposure and the melanin content, cell cycles, cell apoptosis and mRNA express level were measured respectively.</p><p><b>RESULTS</b>Melanin content in melanocytes was increased significantly after exposed to 0.2 J/cm(2) UVA. Melanin content in melanocytes was decreased after treatment with 10.0 mmol/ml nicotinamide following UVA exposure, but the cell cycles and the cell apoptosis rate were not significantly altered. mRNA express levels of TYR, TRP-1 were modulated by nicotinamide.</p><p><b>CONCLUSION</b>Nicotinamide has more effect on decreasing melanin genesis after UVA exposure, nicotinamide also plays a role in modulating the mRNA express of TYR, TRP-1 gene. It is possible to consider nicotinamide as an efficient and safe sun screen to provide a certain level of protection for UVA exposed skin.</p>

Low back pain prevalence of female workers in flat-grained veneer wood industry / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the low back pain(LBP) and its cause on female workers in flat-grained veneer wood industry.</p><p><b>METHODS</b>Bending posture was analyzed by observation and the prevalence of low back pain was investigated by physical examination and questionnaire among 299 female workers.</p><p><b>RESULTS</b>The prevalence of fatigue compliant in selecting, remending and sticking workers was 68.8%, 66.7% and 59.0%, respectively, which mainly involved in the part of low back. The prevalence of low back pain in selection (53.8%) and remending (58.7%) workers was higher than that in sticking workers (30.1%), which was in accordance with the tenderness between L4/L5 or L5/L6 and on the psoas major. Posture analysis indicated that the biggest bending range of selecting and remending workers (80 degrees ) was larger than that of sticking workers (60 degrees ), as well as the daily bending times[(4396+/-817), (1696+/-286), (1094+/-476)] and the time they kept bending[(6.5+/-0.6), (6.2+/-1.3), 4.5+/-0.9) h].</p><p><b>CONCLUSION</b>Bending posture is common among female workers especially those who work in selecting and remending and might be the major causes for the high prevalence of LBP in flat-grained veneer wood industry.</p>

The intervention of nicotinamide on skin melanocyte's cell proliferation after UVA (365 nm) exposed / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the interference effect of nicotinamide on UVA-induced cell proliferation in human skin melanocyte.</p><p><b>METHODS</b>To apply the optimum UVA dose expected to cause cell proliferation: 0.2 cm2, nicotinamide was added after the 0.2 cm2 UVA exposure immediately or 48 h later, then the rate of cell proliferation, calcium concentration and the activities of Na+-K+, Ca2+-ATP enzymes of melanocytes were measured respectively.</p><p><b>RESULTS</b>After treatment with 1.000 mg/ml nicotinamide following UVA exposure, the rate of cell proliferation was decreased significantly 24 hours later. Treatment with 0.125 mg/ml nicotinamide 48 hours after UVA exposure also significantly inhibited the cell proliferation; 1.25 mg/ml nicotinamide increased calcium concentration in cells; 0.250 mg/ml nicotinamide increased the activities of Na+-K+, Ca2+-ATP enzymes in melanocytes (P < 0.05).</p><p><b>CONCLUSION</b>Nicotinamide has more obvious effect on inhibiting melanocyte's proliferation if added immediately following UVA exposure. Our discovery indicated that nicotinamide may affect the melanocyte through modulating the calcium concentration. It is possible to consider nicotinamide as an efficient and safe sun screen to provide a certain level of protection for UVA exposed skin.</p>

Assessment of exposure to extremely low frequency magnetic field emitted from monitors / 中华预防医学杂志

<p><b>OBJECTIVES</b>To investigate intensity of extremely low frequency magnetic field (ELFMF) emitted from cathode-ray tubes (CRT) of monitors in various directions and to find ways to avoid its influence.</p><p><b>METHODS</b>Two hundred CRT monitors and 10 monitors with liquid-crystal display (LCD) were selected. Their ELFMF was detected for three times in front of the monitor at an interval of every 5 cm from 0 cm to 50 cm, as well as at various directions from the monitor.</p><p><b>RESULTS</b>Intensity of ELFMF significantly attenuated at regular operating position (30 - 40 cm) from 0 cm to 50 cm in front of both 38 cm and 43 cm CRT monitors (P < 0.05). Intensity exceeded 0.4 microT both within 15 cm and 10 cm in front of 38 cm and 43 cm monitors. The highest intensity was found at the upright top position of both kinds of monitors, 9.54 microT for 38 cm monitor and 6.38 microT for 43 cm one, respectively.</p><p><b>CONCLUSIONS</b>It is suggested to keep away from monitor screen as possible when operating a computer, to reduce unnecessary operation in front of a monitor screen, and to shorten operating time. To avoid more hazards from interactive interference between computers, it is necessary to increase distance between monitors.</p>