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PubMed1993

[Experimental study on the skin by laser-assisted anastomosis].

Incisions in 35 rats were performed on the back bilaterally. Both incisions were sutured by hand with threads at equal interval. One of the incisions immediately welded by laser after suture, the others as follow. When 24 hours after suture, the stitches of the laser welded incisions were removed. The maximal strength force and histology of the bilateral incisions were measured and examined respectively at 1, 3, 7 and 14 days after the operation. The results showed: there was obviously significant differences of the strength force within 3 days between the two incisions. There was slightly inflammatory reactions, no scar and ideal healing in laser welded incisions.

Animals↗
PubMed1989

Lung function of welders of zinc-coated mild steel: cross-sectional analysis and changes over five consecutive work shifts.

Spirometric lung-function measurements were conducted 5 days before and after the work shift of 11 welders of zinc-coated steel, ten nonwelders who were indirectly exposed to welding fumes, and 17 controls. The exposure to dust and zinc of all participants was monitored personally using PAS-6 samplers. Geometric mean concentrations for welders were 0.91 mg/m3 (dust) and 34.0 micrograms/m3 (zinc). Cross-sectional analysis of Monday morning values showed no differences in lung-function parameters between groups. However, the number of years the participants were engaged in welding was of borderline statistical significance and correlated negatively with values of FEV1 and FEV1/FVC. Changes in lung function over a work shift or a working week were not related to the exposure level.

Adult↗
PubMed2006

Progressive motor syndrome in a welder with pallidal T1 hyperintensity on MRI: A two-year follow-up.

Chronic exposure to manganese (Mn) fume during welding may lead to mainly extrapyramidal syndrome that is resistant to treatment. We present a 32-year-old patient who developed severe postural instability, Parkinsonism, dystonia, and pyramidal signs in the 10th year of welding. The neurological condition of the patient worsened markedly in the following 3 years, resulting in severe disability rendering him to be assisted in all his daily activities and he did not benefit from any dopaminergic agent. T1 sequences of the MRI of the brain showed pallidal hyperintensity symmetrically. Welders in our country often protect their eyes but ignore to use tools that protect them from inhalation of the fume. Since chronic Mn toxicity may cause serious disability and irreversible neurological disturbances, we strongly believe that it is necessary to inform welders and their employers about this potential hazard.

Adult↗
PubMed1999

Neurobehavioral and respiratory findings in jet engine repair workers: A comparison of exposed and unexposed volunteers.

Workers repairing jet engines had respiratory, rheumatic, and neurobehavioral symptoms. They had welded and ground stainless steel parts using hard metal tools and cleaned metal with chlorinated and fluorinated organic solvents. We compared 154 workers and 112 unexposed subjects, all volunteers of similar ages and with similar educational levels, for abnormalities on chest radiographs, spirometric measurements, and questionnaires. Also appraised were performance of reaction time, balance, blink reflex latency, color discrimination, Culture Fair, vocabulary, slotted pegboard, trail making A and B, profile of mood states (POMS), and frequencies of 35 symptoms. Compared to unexposed subjects, workers had significantly more respiratory symptoms but no differences in pulmonary function. They had significantly prolonged simple and choice reaction time (P<0.0001), and abnormal balance with eyes open and eyes closed (P<0. 0001), and abnormal color discrimination. Blink reflex latency was abnormal in both exposed workers and in local unexposed compared to other reference groups. Focus of the inquiry on lung disease helped ensure that for neurobehavioral tests confounding factors were minimal and known biases were small. We tentatively attribute the neurobehavioral impairments and increased symptom frequencies to chlorinated solvent exposure. Excessive respiratory symptoms are attributed to welding stainless steel combined with cigarette smoking. Specifically, manganese exposure may have affected the respiratory and the central nervous systems.

Adult↗
PubMed1987

Occupational chronic exposure to metals. I. Chromium exposure of stainless steel welders--biological monitoring.

External and internal chromate exposure of 103 stainless steel welders who were using manual metal are welding (MMA), metal inert gas welding (MIG) and both methods, were measured by ambient and biological monitoring. At the working places the maximum chromium trioxide concentrations were 80 micrograms/m3. The median values were 4 micrograms/m3 (MMA) and 10 micrograms/m3 (MIG). The median chromium concentrations in erythrocytes, plasma and urine of all welders were less than 0.60, 9.00 and 32.50 micrograms/l. For biological monitoring purposes, chromium levels in erythrocytes and simultaneously in plasma seem to be suitable parameters. According to our results, chromium levels in plasma and urine in the order of 10 and 40 micrograms/l seem to correspond to an external exposure of 100 micrograms chromium trioxide per cubic metre, the technical guiding concentration (TRK-value). Chromium concentrations in erythrocytes greater than 0.60 micrograms/l indicate an external chromate exposure greater than the TRK-value.

Adult↗
PubMed1992

Erythrocyte antioxidant system and serum ceruloplasmin levels in welders.

The erythrocyte antioxidant system (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione) and serum ceruloplasmin were studied in workers chronically exposed to welding fumes and gases, which are thought to be oxidant pollutants. Fifty-four healthy men using two electric arc welding processes (manual metal arc on stainless steel and mild steel, and metal inert gas on mild steel) were studied. The possible effects of cigarette smoking were also considered. The erythrocyte antioxidant system was in the normal range for all welders. Serum ceruloplasmin was significantly enhanced only in smoking welders and higher in manual metal arc than in metal inert gas welders, suggesting that the increase is related to the severity of the oxidant threat, which is more stressful for the workers using the manual metal arc technique because of the presence of stainless steel particles in the fumes. Although cigarette smoking alone did not increase serum ceruloplasmin levels, it affected the response to oxidant stress in welders.

Adult↗
PubMed1988

Decreased serum ceruloplasmin concentration in aluminum welders exposed to ozone.

During an epidemiological survey on arc welders, serum copper and ceruloplasmin were determined in two groups of workers. One group consisted of aluminum welders who were divided into two groups: 13 welders working inside aluminum tanks (confined atmosphere) and 8 welders engaged in the production of vans for dump trucks (nonconfined atmosphere). The reference group consisted of 26 workers of the same plant who were not exposed to welding fumes. Ozone, the major pollutant in aluminum arc welding, was thought to be the principal factor in the significant decrease (P less than 0.01) of mean ceruloplasmin in confined welders. This decrease in the level of ceruloplasmin was still within the reference values and was not linked to age or to tobacco consumption. We found a linear relationship between ceruloplasmin concentration and the cumulated worktime along the week. This effect could be a sign in the serum of a lung reaction against oxidant activity in this type occupational exposure.

Adult↗
PubMed1995

A new technology for direct restorative alloys.

OBJECTIVES: The purpose of this study was to develop a new technology for preparing mercury-free metallic dental restorative materials. METHODS: The novel approach relies on the cold welding of surface treated silver particles. At ambient temperature, intermetallic compound formation takes place spontaneously at the silver-tin interface. The ability of a loose powder to consolidate at ambient temperature under moderate pressure and within a short time duration was investigated for various mixtures of elemental silver, tin, and pre-alloyed silver-coated powders. Surface treatment aimed at removing silver surface oxide layers is done with a dilute acid. The compressive and the transverse rupture strengths of several of the consolidated powder mixtures were determined. RESULTS: Cold-welding of surface-treated powder particles takes place across the silver-silver interface and is promoted by exposure to a mild acid. Powder mixtures containing approximately 50% silver powder, 40% silver-coated silver-tin intermetallic compound particles, and a small silver-tin fraction deposited from an aqueous solution display very good condensability, depending on the amount of silver-silver interface area available. The attained rupture strength values (200 Mpa) were higher than those of amalgams; the compressive strengths (120 MPa) and hardness values (100 KHN), however, were lower than those found for amalgams. SIGNIFICANCE: Mercury-free silver-tin powder mixtures can be processed for use as metallic composite dental restorative materials.

Analysis of Variance↗
PubMed2006

Parkinsonism due to manganism in a welder: neurological and neuropsychological sequelae.

A 33-year-old welder with 3 years of exposure to manganese (Mn) bearing welding fumes was seen by neurologists for cognitive and motor complaints. He exhibited signs and symptoms of Parkinson's disease, including tremor, bradykinesia, gait disturbance and cogwheel rigidity. However, he was young and had significant inattention and forgetfulness, had found levodopa unhelpful and moved with a cock-walk gait, all of which suggested manganism. His serum and urine levels of Mn were, in fact, elevated, and his brain MRI had increased T1-weighted signal intensities in the basal ganglia bilaterally (globus pallidus) consistent with Mn deposition. Two years later, he underwent comprehensive neuropsychological testing. Clinical history indicated a mild tremor and emotional dysfunction with irritability, anxiety, and depression with psychotic features. He showed deficits in cognitive flexibility, information processing and speed, and greatly reduced motor speed, which are consistent with a fronto-subcortical process. These findings support a diagnosis of early onset parkinsonism from welding.

Adult↗
PubMed2006

A retrospective cohort study of Parkinson's disease in Korean shipbuilders.

OBJECTIVE: We performed a retrospective cohort study in South Korea to clarify the role of occupational exposure, especially to welding, in the etiology of Parkinson's disease (PD). METHODS: We constructed a database of subjects classified into an exposure group (blue-collar workers) and a non-exposure group (white-collar workers) in two shipbuilding companies. Jobs of blue-collar workers were categorized into the first group of welding, the second group of fitting, grinding and finishing, cutting, and the other group. To determine new cases of PD during the follow-up period (1992-2003), we used the physician billing claims database of the National Health Insurance Corporation. For the detected PD patients in the physician billing claims database, a neurologist in our research team confirmed the appropriateness of each diagnosis by reviewing medical charts. Based on the review, we confirmed the numbers of new cases of PD and calculated the relative risk (RR) and the 95% confidence intervals (CI) by Cox regression analysis. RESULTS: In a backward selection procedure, 'age' was a significant independent variable but exposure was not. Furthermore, the RR in welders (high exposure group) was also insignificant and less than that in others (very low exposure group). CONCLUSION: This longitudinal study of shipbuilding workers supports our previous case-control studies suggesting that exposure to manganese does not increase the risk of PD.

Age of Onset↗
PubMedDate not supplied

Semen quality of Indian welders occupationally exposed to nickel and chromium.

The semen quality of 57 workers from a welding plant in South India and 57 controls was monitored. Blood nickel and chromium concentrations were determined by ICP-MS. Analysis of semen samples was performed in accordance with World Health Organization criteria. The blood level of nickel and chromium for the 28 exposed workers was 123.3 +/- 35.2 and 131.0 +/- 52.6 microg/l, resepctively, which was significantly higher than the 16.7 +/- 5.8 and 17.4 +/- 8.9 microg/l for the control group (n=27). Sperm concentrations of exposed workers were 14.5 +/- 24.0 millions/ml and those of the control group were 62.8 +/- 43.7 millions/ml. Rapid linear sperm motility was decreased in exposed workers compared to controls. There was a significant positive correlation between the percentage of tail defects and blood nickel concentration in exposed workers. The sperm concentration showed a negative correlation with blood chromium content in workers. More abnormal characteristics were found in the semen of exposed workers. Semen abnormalities correlated with the number of years of exposure to welding fumes containing nickel and chromium.

Adult↗
PubMedDate not supplied

Assessment of risk of lung cancer for welders.

Certain welding fumes contain significant amounts of chromium, manganese, and nickel, and trace amounts of arsenic and lead. These metals exhibit mutagenicity in one or more in vitro bioassays, and several are strongly suspected human carcinogens, albeit in unknown forms. It might, therefore, be expected that welders experience an excess risk of respiratory tract cancer because of their occupation. A survey of the world literature has disclosed 22 epidemiological studies of cancer incidence among welders, 16 of which yield a total of 586 cases of lung cancer observed, based on approximately 600,000 man-years at risk; a risk ratio of less than unity was excluded within 95% confidence limits for 5 of these studies. A risk ratio of 1.3 was not excluded in any study. Although there may be many possible origins to the excess risk, if welders of stainless steels suffer an "equivalent lung cancer risk" to that of chromate workers because of their equivalent chromium (VI) exposure, then a resulting three-fold risk ratio for 10% of all welders engaged in stainless steel welding would account for the total over-incidence experienced by the entire occupational group.

Adult↗
PubMedDate not supplied

Thoracic magnetic dust content, occupational exposure, and respiratory status of shipyard welders.

The net thoracic magnetic moment of 58 highly exposed nonsmoking shipyard welders and 13 unexposed nonsmoking electricians was measured with an alternating current susceptibility bridge. The welding cohort exhibits a thorax magnetic moment, which on the average is less diamagnetic than that of the controls. This shift is consistent with a median lung burden of 110 mg Fe3O4, or 220 mg of the welding fumes characteristic for shipyard exposures. Among welders with 5+ yr of exposure, there is a slight but statistically significant correlation (r = 0.49) (p less than .0001) between inferred lung burden and lifetime occupational exposure. Although chronic bronchitis incidence and average lung function parameter values of the welders are different from those of the nonexposed cohort, respiratory status does not correlate further with either self-reported exposure or measured lung retention.

Adult↗
PubMed1994

Chronic interstitial lung disease in a welder of galvanized steel.

A 32-year-old man who took pride in his skill and speed as a welder suffered two relatively brief intense exposures (three months each) to welding fumes under relatively confined space conditions. He developed shortness of breath within 18 months of beginning work, with severe impairment of his diffusion capacity. This remains some months later despite discontinuing his welding activities.

Adult↗
PubMed1991

Lung cancer in mild steel welders.

To investigate lung cancer risk, the authors conducted a historical cohort mortality study of 4,459 mild steel welders who had been employed at three midwestern plants which manufactured heavy equipment. Follow-up began in the mid-1950s and extended through 1988. All welders had at least 2 years welding experience (average duration, 8.5 years). This cohort had no occupational exposure to asbestos or stainless steel fumes (containing nickel and chromium), two potential confounders in previous welders studies. A comparison population of 4,286 nonwelders, all with at least 2 years employment at the same plants, was also studied. Nonwelders had never been welders and were allowed to have no more than 90 days employment as a painter, foundryman, or machinist. Sampling data collected from 1974-1987 indicated that welders were exposed to 6-7 mg/m3 of total particulate and 3-4 mg/m3 of iron oxide, while nonwelders had negligible exposures to welding fumes. When compared with the United States population, both welders and nonwelders had elevated rates for lung cancer (standardized mortality ratios (SMRs): welders, SMR = 1.07; nonwelders, SMR = 1.17), but neither SMR was significantly elevated. Limited smoking data based on a 1985 survey indicated that both welders and nonwelders smoked more than the United States population, possibly accounting for part of their elevated lung cancer rates. There was no trend of increased risk for welders with increased duration of exposure. The only other cause of death significantly elevated was emphysema among welders. Nonmalignant respiratory disease was not elevated for welders (SMR = 0.96). When welders were compared with nonwelders directly for lung cancer, the rate ratio was 0.90.

Cause of Death↗
PubMed1997

Socioeconomic status and lung cancer incidence in men in The Netherlands: is there a role for occupational exposure?

STUDY OBJECTIVE: To evaluate the influence of occupational exposure to carcinogens in explaining the association between socioeconomic status and lung cancer. DESIGN: A prospective cohort study. Data on diet, other lifestyle factors, sociodemographic characteristics and job history were collected by means of a self administered questionnaire. Follow up for incident cancer was established by record linkage with a national pathology register and with regional cancer registries. SETTING: Population originating from 204 municipalities in The Netherlands. PARTICIPANTS: These comprised 58 279 men aged 55-69 years in September 1986. After 4.3 years of follow up there were 470 microscopically confirmed incident lung cancer cases with complete data on dietary habits and job history. MEASUREMENTS AND MAIN RESULTS: Estimation of occupational exposure to asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes was carried out by two experts, using information on job history from the baseline questionnaire. Socioeconomic status was measured by means of highest attained level of education and two indicators based on occupation. In the initial multivariate analyses of socioeconomic status and lung cancer, adjustment was made for age, smoking habits, intake of vitamin C, beta-carotene and retinol, and history of chronic obstructive pulmonary disease or asthma. Additional adjustment for occupational exposure to the four carcinogens mentioned above did not change the inverse association between the level of education and lung cancer risk (initial model: RR highest/lowest level of education = 0.53; 95% CI 0.34, 0.82; additional model: RR highest/lowest level of education = 0.53; 95% CI 0.34, 0.84). Nor was the association between the two occupation based indicators of socioeconomic status and lung cancer risk influenced by occupational exposure to carcinogens. The effect of occupational exposure on the association between the level of education and lung cancer risk did not differ between ex-smokers and current smokers. CONCLUSIONS: Occupational exposure to asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes could not explain the inverse association between socioeconomic status and lung cancer risk. More research which explicitly addresses possible explanations for the association between socioeconomic status and lung cancer risk is needed.

Aged↗
PubMed1988

Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops.

The incidence of cancer in 12,693 shipyard and machine shop male workers (1689 welders, 4308 platers, 6003 machinists, 693 pipe fitters) employed for at least one year between 1945 and 1960 was investigated in a retrospective cohort study. The welders had welded only mild steel and had not been exposed to hexavalent chromium containing fume. The follow up was 99.7% complete and the total number of person-years was 304,682. The incidence of cancer in 1953-81 was ascertained through the Finnish Cancer Registry. The observed numbers of cases of cancer were compared with the expected numbers based on regional urban rates. The smoking habits of the cohort were surveyed with a postal questionnaire sent to a sample of 961 workers. The smoking habits of the cohorts were similar and smoking was not more common than among the general population. The total number of cases of cancer was 611 (exp 629) among the shipyard workers and 376 (exp 388) among the machine shop workers. The incidence of lung cancer was increased among the shipyard workers (obs 227, exp 192). This excess was observed in all the worker groups and was most evident for the pipe fitters and platers. Among the machine shop workers, the incidence of lung cancer was lower than expected with the exception of the welders who had a slightly raised risk of lung cancer (obs 14, exp 10). The incidence of laryngeal cancer was slightly raised among the shipyard workers (obs 24, exp 20) but not in the machine shop workers. No excess risk was observed among the welders. The incidence of cancer of the prostate was increased among the machine shop workers (obs 39, exp 31) but not in the shipyard workers. The excess was statistically significant for the welders. No pronounced excess could be found for other types of cancer. Analysis by the duration or exposure showed that the excess of lung cancer in the shipyard workers was most evident during the last period of observation (1972-81). No other trends were obvious and the slight excess of lung cancer observed among the welders did not increase with increasing follow up time. No excess risk for mesothelioma was found. The small excess of lung cancer in welders could be due to chance. The fact that only a small and statistically insignificant excess of lung cancer could be found among this group of heavily exposed welders suggest that if the risk of lung cancer was associated with welding this risk must nowadays be low and probably too low to be unequivocally detected in most epidemiological studies.

Finland↗