Electromagnetic Fields ; Magnetic Fields ; Microwaves ; adverse effects ; Television

OBJECTIVETo investigate the interference effect of nicotinamide on UVA-induced melanin genesis and melanin transport in human skin melanocyte.

METHODSThe 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.

RESULTSMelanin 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.

CONCLUSIONNicotinamide 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.

Cells, Cultured ; Humans ; Melanins ; biosynthesis ; Melanocytes ; drug effects ; metabolism ; radiation effects ; Niacinamide ; pharmacology ; Ultraviolet Rays ; adverse effects

OBJECTIVESTo 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.

METHODSTwo 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.

RESULTSIntensity 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.

CONCLUSIONSIt 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.

Computers ; Electromagnetic Fields ; adverse effects ; Environmental Exposure ; adverse effects ; Equipment Safety ; Humans ; Occupational Exposure ; adverse effects ; Radiation Monitoring ; methods ; Risk Assessment

OBJECTIVETo investigate the interference effect of nicotinamide on UVA-induced cell proliferation in human skin melanocyte.

METHODSTo 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.

RESULTSAfter 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).

CONCLUSIONNicotinamide 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.

Cell Proliferation ; drug effects ; radiation effects ; Cells, Cultured ; Humans ; Melanocytes ; cytology ; Niacinamide ; pharmacology ; Skin ; cytology ; Ultraviolet Rays

OBJECTIVE: Using CO II sequences to identify common species of carrion-breeding flies and larvae. METHODS: flies and larvae were collected on the corpses of rats in Zhengzhou district, DNA was extracted, CO II sequences were amplified and sequenced. Clustalx and MEGA 4.0 software were used to analyze the gene sequences and to construct the phylogenetic trees. RESULTS: There was no significant gene difference between adults and larvae. COII gene sequences could be used to identify Boettcherisca peregrina, Aldrichina grahami and Lucilia illustris but they could not distinguish Lucilia cuprina from the Lucilia sericata because of their close evolutionary distance and single nucleotide polymorphisms in aldrichina grahami and Lucilia illustris populations were found. CONCLUSION CO II sequence of mtDNA in Zhengzhou district can be used effectively to identify some common species of carrion-breeding fly. The method is simple and accurate.
Animals ; Base Sequence ; China ; DNA Primers ; DNA, Mitochondrial/genetics* ; Diptera/genetics* ; Electron Transport Complex IV/genetics* ; Entomology ; Forensic Medicine/methods* ; Genes, Insect ; Larva/genetics* ; Phylogeny ; Polymerase Chain Reaction/methods* ; Rats ; Sequence Analysis, DNA ; Species Specificity

OBJECTIVETo investigate the use of dendritic cells derived from mice bone marrow to evaluate the cutaneous allergic reaction induced by chemical sensitizers.

METHODSDendritic 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.

RESULTSCD86 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.

CONCLUSIONChemical 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.

Animals ; B7-2 Antigen ; metabolism ; Cells, Cultured ; Dendritic Cells ; drug effects ; immunology ; metabolism ; Dinitrochlorobenzene ; pharmacology ; Interleukin-12 ; metabolism ; Interleukin-1beta ; metabolism ; Interleukin-6 ; metabolism ; Mice ; Mice, Inbred C57BL ; Nickel ; pharmacology ; Sodium Dodecyl Sulfate ; pharmacology

OBJECTIVETo investigate the effects of occupational lead exposure on the bone mineral density and the bone metabolism in exposed workers.

METHODSTwo 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).

RESULTSThe 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.

CONCLUSIONSThe occupational exposure to lead could cause the decrease of the bone mineral density, lead to the osteoporosis, and may affect the bone metabolism.

Adult ; Aged ; Biomarkers ; blood ; urine ; Bone Density ; drug effects ; Bone and Bones ; drug effects ; metabolism ; Case-Control Studies ; Female ; Humans ; Lead ; adverse effects ; blood ; urine ; Male ; Middle Aged ; Occupational Exposure ; adverse effects ; Osteoporosis ; chemically induced ; Young Adult

OBJECTIVETo study the low back pain(LBP) and its cause on female workers in flat-grained veneer wood industry.

METHODSBending posture was analyzed by observation and the prevalence of low back pain was investigated by physical examination and questionnaire among 299 female workers.

RESULTSThe 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].

CONCLUSIONBending 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.

Adult ; Female ; Humans ; Low Back Pain ; epidemiology ; etiology ; Occupational Diseases ; epidemiology ; etiology ; Posture ; Prevalence ; Risk Factors ; Surveys and Questionnaires ; Wood

OBJECTIVETo study the changes of serum total calcium (Ca) and inorganic phosphate (P) levels during children growth and related factors.

METHODSUsing a stratified-multi-steps-cluster sampling method, we selected 2,342 healthy children aged 10-18 years from urban and suburban areas of Beijing from September 2001 to December 2001 to test the levels of serum Ca and P. Their meal status was also surveyed to analyse the correlation of the leves of serum Ca and P with sex, age, height, weight, and diet on statistic basis.

RESULTSThe Ca levels of Beijing children were (2.39 +/- 0.12) mmol/L, which had a positive correlation with age, height, and weight (P < 0.01). The Ca levels of female children were somewhat higher than those of male [male, (2.38 +/- 0.12) mmol/L; female, (2.39 +/- 0.12) mmol/L; P < 0.05]. The Ca levels of urban children were significantly higher than those of suburban children [urban, (2.40 +/- 0.13) mmol/L; suburban, (2.37 +/- 0.10) mmol/L; P < 0.001]. The P levels of Beijing children were (1.39 +/- 0.18) mmol/L, which had a negative correlation with age, height, and weight (P < 0.01). The P levels of male children were significantly higher than those of female [male, (1.43 +/- 0.18) mmol/L; female, (1.36 +/- 0.17) mmol/L; P < 0.001]. The P levels of urban children were significant higher than those of suburban children [urban, (1.41 +/- 0.19) mmol/L; suburban, (1.38 +/- 0.16) mmol/L; P < 0.001]. The Ca levels of Beijing children had a negative correlation with P levels (r=-0.141, P < 0.01). [Ca] x [P] (mmol/L) of Beijing children were 3.32 +/- 0.44. The value of [Ca] x [P] reached peak by 3.45 +/- 0.46 when Beijing children were of 13-14 years old, and then the value declined with increasing age.

CONCLUSIONThe levels of serum Ca and P correlates with sex, age, growth, and diet. The level of serum Ca goes up while P goes down during the children growth.

Adolescent ; Age Factors ; Body Height ; Body Mass Index ; Body Weight ; Calcium ; blood ; Child ; Child Development ; Female ; Humans ; Male ; Phosphorus ; blood ; Reference Values ; Sampling Studies ; Sex Factors ; Urban Health

OBJECTIVETo analyze the relationship between body fat mass and distribution and cardiovascular function in the adult females of Heilongjiang province.

METHODSBased on the statistic variable random sampling principal, we selected 1903 healthy adult females with ages of 18 - 70 years old in Heilongjiang province to conduct the study. The height, body weight, waist, chest measurement and waist-hip ratio (WHR) were measured. Body components quota including fat weight, lean weight, percentage of body fat (PBF) were taken respectively; systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke index (SI), left cardiac work (LCW) and systemic vascular resistance (SVR) were determined.

RESULTSThe PBF and WHR increased with aging, and the PBF of those with ages of 18-, 30-, 40-, 50- and 60 - 70 year's old were (16.86 +/- 5.37)%, (18.43 +/- 4.89)%, (20.99 +/- 5.79)%, (23.47 +/- 5.74)% and (25.77 +/- 6.38)%, respectively (F = 154.46, P < 0.01); and the WHR were 0.77 +/- 0.05, 0.80 +/- 0.05, 0.83 +/- 0.05, 0.85 +/- 0.06 and 0.89 +/- 0.07, respectively (F = 229.84, P < 0.01). The HR, CO, CI, SBP, DBP and LCW were (75.45 +/- 0.35) bpm, (4.42 +/- 0.02) L/min, (2.78 +/- 0.01) L * min(-1) * m(-2), (114.94 +/- 0.40) mm Hg (1 mm Hg = 0.133 kPa), (64.90 +/- 0.28) mm Hg, (4.57 +/- 0.03) kg * m/m(2) respectively in normal PBF groups; whereas the HR, CO, CI, SBP, DBP and LCW in the PBF obesity groups were (77.42 +/- 0.88) bpm, (4.54 +/- 0.05) L/min, (2.88 +/- 0.03) L * min(-1) * m(-2), (120.55 +/- 1.00) mm Hg, (66.56 +/- 0.71) mm Hg and (4.86 +/- 0.07) kg * m/m(2), respectively, F values were 3.182, 9.173, 8.478, 13.497, 2.637, and 10.631, respectively (all P values < 0.05) after the adjustment of age, height and weight, PBF was positively correlated with HR, CO, CI, SI, SBP, DBP and LCW (r values were 0.06, 0.11, 0.10, 0.11 and 0.12, respectively, all P values < 0.05); WHR was positively correlated with CI, SI, SBP, DBP, LCW and SVR (r values were 0.14, 014, 0.19, 0.18, 0.10 and 0.12, respectively, all P values < 0.01) after the adjustment of age, height and weight.

CONCLUSIONPBF augmentation and abdominal obesity in females can result in cardiac dysfunction such as cardiac overload, CO increasing and blood pressure rising.

Adiposity ; Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group ; Blood Pressure ; Cardiac Output ; Female ; Heart Rate ; Humans ; Middle Aged ; Vascular Resistance ; Waist-Hip Ratio ; Young Adult