[The relationships of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) inhalational dose and oxidative damage in foundry workers]

Objective: To investigate the potential dose-response relationship between PCDD/Fs inhalational exposure and oxidative damage to DNA and lipid in foundry workers. Methods: The participants were divided into three groups, including exposure group, administrator group and control group. The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in air environment were determined by isotope dilution high resolution capillary column gas chromatography/high resolution mass spectrometry (HRGC-HRMS). The inhalational dose of PCDD/Fs were evaluated by Houmen's model. Urinary 8-OHdG was analyzed by high performance liquid chromatography-electrochemical detector (HPLC-ECD). Urinary 8-iso-PGF2ɑ were determined by ELISA. Results: The PCDD/Fs environmental concentrations of three groups (pg·TEQ/m) were 0.21±0.08, 0.03±0.01, 0.0012±0.0007 (P<0.05) , respectively. The inhalational dose of exposure group (92.54 (32.90~264.49) fg·TEQ/kg·d) was 5.4 folds higher than the administrator group, and was 201 times more than control group. The levels of urinary 8-OHdG (nmol/L crea) of three groups were 3.25 (1.07~15.36) , 2.72 (0.75~16.07) , 2.17 (0.38~17.07) (P<0.05) and the levels of urinary 8-iso-PGF2ɑ (nmol/L crea) were 19.11 (9.33~76.50) , 20.95 (8.40~79.31) , 11.48 (4.85~37.80) (P<0.05) , respectively. The multiple linear regression analysis revealed that there were significantly increased trend for levels of urinary 8-OHdG and 8-iso-PGF2ɑ as PCDD/Fs exposure levels increased, after adjustment for age, sex, smoking statue, alcohol use and BMI (P<0.01). Conclusion: There was a dose-response relationship between PCDD/Fs inhalational exposure and oxidative damage in foundry workers.

[The analysis of adverse health effects of occupational hazards factors in one solid waste landfill]

OBJECTIVE

To determine occupational hazards in work sites of a large solid waste landfill and analyze their adverse health effects.

METHOD

The national standardized detection methods were used to determine dust concentration, harmful gas and physical factors in worksites. Routine physical examination, pulmonary function, hearing tests and nervous system test were performed in workers for 2 consecutive years. Urine lead, cadmium and mercury contents were detected. The comet assay was use to measure DNA damage in peripheral blood lymphocytes among workers.

RESULT

The main occupational hazard factors in this solid landfill are dust, harmful gas, high temperature and noise. The oxides, carbon monoxide, and noise and high temperatures in summer at some work sites exceeded the national occupational exposure limits. The prevalence of respiratory inflammation and rate of pulmonary function decrease among front-line workers and on-site technical managers are 21.2% and 11.5%, which are significantly higher than those among administrative staff (7.1% and 0) (P < 0.05). Nervous system abnormalities rate of front-line workers and on-site technical managers was 50.0%, which is significantly higher than that (26.7%) of administrative staff (P < 0.05). Because of long-term exposure to high intensity noice, hearing loss rate of bulldozer drivers was 10.3%. In addition, about 75% of workers with DNA damage in peripheral blood lymphocyte are front-line workers.

CONCLUSION

Adverse health effects from occupational hazards were observed among workers in this solid waste landfill.

[Smoking status or age impact on urinary 8-hydroxy-2'-deoxyguanosine in electrical and electronic equipment waste dismantling workers]

OBJECTIVE

To investigate the smoking or age impact on occupational workers in electrical and electronic equipment waste (e-waste) dismantling procedure, using 8-Hydroxy-2'-deoxyguanosine (8-OHdG) in the urine as a biomarker for oxidative damage to DNA.

METHODS

The pre-workshift and post-workshift urinary samples of 64 male workers in e-waste dismantling procedure were detected by solid-phase extraction-high performance liquid chromatography-electrochemical detector (SPE-HPLC-ECD). The data were statistically analyzed by two factors, age or smoking status.

RESULTS

The 8-OHdG levels in non-smokers' urines (n = 42) were higher than those in smokers' urines (n = 22). The levels in pre-workshift urines were detected at (8.25 +/- 4.23) micromol/mol creatinine in non-smokers, while the values were (5.44 +/- 1.18) micromol/mol in smokers. And, the levels in post-workshift were detected at (43.12 +/- 16.19) micromol/mol creatinine in non-smokers, while the values were (14.82 +/- 2.51) micromol/mol in smokers. The 8-OHdG levels in pre-workshift urines were not different between non-smokers and smokers (t = -0.81, P = 0.42), however after 1 day exposure, urinary 8-OHdG levels were significantly increased in non-smokers than those in smokers (t = - 2.33, P < 0.05). On the other hand, the subjects were divided into five groups according to their age. The 8-OHdG levels in pre-workshift urines were (1.86 +/- 0.66), (3.57 +/- 0.54), (8.12 +/- 4.10), (11.39 +/- 3.70) micromol/mol creatinine in < 20 years group (n = 6), 20 -years group (n = 22), 30 - years group ( n = 23), 40 - 49 years group (n = 11) respectively. No effect of age was found on the pre-workshift urinary 8-OHdG levels (F = 0.98, t = 0.41). However, it was found that the post-workshift urinary 8-OHdG levels increased along with the e-waste workers' age (F = 4.81, P = 0.03), and they were (4.19 +/- 2.85), (19.89 +/- 5.26), (28.89 +/- 14.61), (34.94 +/- 12.50) micromol/mol creatinine in < 20 years group, 20 - years group, 30 - years group, 40 - 49 years group respectively.

CONCLUSION

The urinary 8-OHdG levels in the e-waste dismantling workers might be inhibited by smoking status. The post-workshift urinary 8-OHdG levels increased along with the e-waste workers' age.

[Clinical value of 24-hour ambulatory electrocardiography in childhood myocarditis]

OBJECTIVE

To investigate the characteristics of 24-hr ambulatory electrocardiography (DCG) of children with myocarditis and to study the clinical value of DCG in the diagnosis of childhood myocarditis.

METHODS

24-hr DCG findings, including abnormal DCG rate, and number, grade and distribution of ventricular premature beat (PVC), as well as heart rate variability, from 59 children with myocarditis were retrospectively reviewed and compared with those detected in 41 children without heart disease.

RESULTS

86.4% of patients with myocarditis showed abnormal DCG, and compound arrhythmia was commonly seen, but only 46.3% showed abnormal DCG (P < 0.01) and single arrhythmia was predominant in the control group. The number and grade of PVC/24 hrs were not significantly different between the two groups. Compared with the control group, the average pattern PVC was predominant in the myocarditis group (84.6% vs 48.7%; P < 0.05). Monopeak pattern PVC was mostly seen (64.4%), followed by multiple-peak pattern (25.4%) and bi-peak pattern (8.4%) in the myocarditis group, which were significantly different from the control group: monopeak pattern 53.6%, bi-peak pattern 36.6% and multiple-peak pattern 7.3% (P < 0.01).

CONCLUSIONS

The 24-hr DCG characteristics of children with myocarditis are different from the normal controls, suggesting 24-hr DCG monitoring is useful to the diagnosis of childhood myocaditis.

Proton-NMR studies of the effects of ionic strength and pH on the hyperfine-shifted resonances and phenylalanine-82 environment of three species of mitochondrial ferricytochrome c

Ferricytochromes c from three species (horse, tuna, yeast) display sensitivity to variations in solution ionic strength or pH that is manifested in significant changes in the proton NMR spectra of these proteins. Irradiation of the heme 3-CH3 resonances in the proton NMR spectra of tuna, horse and yeast iso-1 ferricytochromes c is shown to give NOE connectivities to the phenyl ring protons of Phe82 as well as to the beta-CH2 protons of this residue. This method was used to probe selectively the Phe82 spin systems of the three cytochromes c under a variety of solution conditions. This phenylalanine residue has previously been shown to be invariant in all mitochondrial cytochromes c, located near the exposed heme edge in proximity to the heme 3-CH3, and may function as a mediator in electron transfer reactions [Louie, G. V., Pielak, G. J., Smith, M. & Brayer, G. D. (1988) Biochemistry 27, 7870-7876]. Ferricytochromes c from all three species undergo a small but specific structural rearrangement in the environment around the heme 3-CH3 group upon changing the solution conditions from low to high ionic strength. This structural change involves a decrease in the distance between the Phe82 beta-CH2 group and the heme 3-CH3 substituent. In addition, studies of the effect of pH on the 1H-NMR spectrum of yeast iso-1 ferricytochrome c show that the heme 3-CH3 proton resonance exhibits a pH-dependent shift with an apparent pK in the range of 6.0-7.0. The chemical shift change of the yeast iso-1 ferricytochrome c heme 3-CH3 resonance is not accompanied by an increase in the linewidth as previously described for horse ferricytochrome c [Burns, P. D. & La Mar, G. N. (1981) J. Biol. Chem. 256, 4934-4939]. These spectral changes are interpreted as arising from an ionization of His33 near the C-terminus. In general, the larger spectral changes observed for the resonances in the vicinity of the heme 3-CH3 group in yeast iso-1 ferricytochrome c with changes in solution conditions, relative to the tuna and horse proteins, suggest that the region around Phe82 is more open and that movement of the Phe82 residue is less constrained in yeast ferricytochrome c. Finally, it is demonstrated here that both the heme 8-CH3 and the 7 alpha-CH resonances of yeast ferricytochrome c titrate with p2H and exhibit apparent pK values of approximately 7.0. The titrating group responsible for these spectral changes is proposed to be His39.

Reversed island forearm fascial flap in hand surgery

We present a technique using a reversed island forearm fascial flap based on the distal portion of the radial artery and veins, with a skin graft on top, to repair a soft tissue defect of the hand. Good results were obtained in a total of 18 operations in 17 postburn cases. The operation can be completed in one stage even when it involves the excision of scar tissue, correction of the secondary deformities of deep structures, and repair of the soft tissue defect of the hand. The advantages and disadvantages of the method and key points of the technique are discussed.