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PubMed2001

UV radiation emitted by selected sources at work stands.

The paper presents the results of UV effective irradiance measurements at work stands for sources such as: welding arcs, gas blowpipes, exposure processes, printing machines and insecticide lamps. The irradiance measurements were performed using broad-band instruments with detector heads corrected to the Polish action spectra (erythematous and conjunctivitis). The obtained values of effective irradiance for the above sources ranged from 0.2 to 8,000 mW/m2. Safe exposure time corresponding to irradiance was calculated for the Polish threshold limit values. For welding processes the spectra of selected welding arcs are presented additionally. These spectra were measured using a fiber-optic spectrometer.

Environmental Monitoring↗
PubMed2003

[Relative risk of pneumoconiosis in welders in metallurgy].

The values of pneumoconiosis risk in welders calculated against the dust doses that induce this pathology do not show linear relationship. In the group of electrical welders, relative risk (RR) was found statistically significant at the doses of 251-500 g; 1001-1500 g and 5501-6000 g. In the group of semi-automatic welders, similar results were observed. Odd ratio, calculated at workposts of semi-automatic welding with CO2 shield, showed that, depending on the size of a daily dose of dust, statistically significant RR was found at the doses of 1.6-2.0; 2.1-2.5; and 2.6-3.0 mg/kg/day. In the group of electric welders, statistically significant RR was observed at the doses of 2.1-2.5; 6.1-6.5; and 9.1-9.5 mg/kg/day. This may suggest that welding dust at workposts of semi-automatic welding is more aggressive. The division of welders by their dates of birth showed that in the group of welders born by 1945, the mean age at which they developed pneumoconiosis was almost 50 +/- 0.4 years, and the mean duration of occupational exposure was 25 +/- 0.3 years. In the group of welders born after 1945, these values were 36 +/- 0.6 years and 12.8 +/- 0.2 years, respectively.

Adult↗
PubMed2003

[Follow-up examination of Danish stainless steel welders previously examined in 1987].

INTRODUCTION: A Danish cohort from 1987 consisting of 226 stainless steel welders and reference persons is part of the European Study Group on Cytogenetic Biomarkers and Health (ESCH). In ESCH increased cancer morbidity and mortality was significantly associated with high levels of chromosomal aberrations, measured in blood samples several years prior to cancer registration. The positive association was found in two cohorts from the Nordic countries and from Italy. MATERIAL AND METHODS: ESCH followed all registered cancer cases and control persons by questionnaires and interviews to obtain information about exposures in the period from the time of blood sampling for chromosomal aberration analysis to the time of cancer diagnosis. In Denmark the total cohort was included in the inquiry and the ESCH questions were supplemented with questions from the Danish National Work Environment Cohort Study 1990-95. RESULTS: Responses from one hundred and forty-four persons showed that seventy-four were employed at the same workplace place as in 1987. Differences in occupational exposures, such as more noise, heat and insufficient lighting and no differences in the self-rated health were found in comparison with the Danish National Work Environment Cohort Study as such and with the sample of metal workers. Only very few of the study persons knew the threshold limit value of welding fumes but a majority found that the working environment had improved during the past ten years. DISCUSSION: This study confirms hazardous exposures in stainless steel welding. The threshold limit value, however, has been lowered since 1987 suggesting there is less cancer risk today from stainless steel welding.

Air Pollutants, Occupational↗
PubMed2005

Accidental death resulting from acetylene cylinder impact.

Acetylene is an inflammable gas commonly used for welding in small-scale industries. We present a case of a 34-year-old male welder who died following injuries sustained from explosion of an acetylene gas-welding cylinder. In this case report, we discuss the circumstances leading to the explosion of the welding cylinder, the autopsy findings, and a brief review of the literature on deaths resulting from blasts of acetylene cylinders.

Accidents, Occupational↗
PubMed2006

[A case of hypersensitivity pneumonitis caused by zinc fume].

A 55-year-old man with a 3-year occupational history of welding was admitted for repeated episodes of fever, cough and dyspnea after inhalation of smoke while welding galvanized steel. A computed tomography (CT) showed diffuse centrilobular nodules, panlobular ground-glass opacity and interlobular septal thickening in both lung fields, and he suffered from hypoxemia (PaO2 = 55.3Torr) while breathing room air. Percentage of lymphocytes in bronchoalveolar lavage fluid increased, and lung biopsy specimens at thoracoscopy revealed lymphocytic alveolitis and organization in air spaces. His symptoms and signs disappeared spontaneously only when he ceased welding. Panlobular ground-glass opacity and interlobular septal thickening improved immediately with oral corticosteroids. Patch tests using metal series gave positive reactions to zinc. We diagnosed this case as hypersensitivity pneumonitis caused by zinc fumes.

Alveolitis, Extrinsic Allergic↗
PubMed1993

Occupational siderosis and welders' lung: a review.

Siderosis of the lung is generally assumed to be a benign condition, not associated with respiratory symptoms. A review of the literature suggests that this assumption may be incorrect, and that siderosis may lead both to symptomatic and functional changes. It is known that iron ore miners have a raised lung cancer mortality, but this has been attributed to smoking, or exposure to tars or radon. Mortality studies among iron workers (haematite miners, welders, iron foundry and steel workers) show, however, that an association exists between working with iron and death, both from lung cancer and other respiratory causes. A number of surveys have examined respiratory function and symptoms among welders. These indicate that welding is associated with obstructive airways disease. The effect of the welding fume on respiratory function and symptoms can be as great as that of smoking. Iron has also been shown to cause fibrosis in some cases. Small functional changes of restriction and loss of lung compliance are often due to iron alone. The fibrosis may be enhanced by associated silica exposure. A number of constituents of welding fume could, along with iron, contribute to pulmonary changes. The presence of siderosis may act as a good marker of exposure to fume and any resulting disability.

Adult↗
PubMed1999

Effects of temperature on tissue thermal injury and wound strength after photothermal wound closure.

BACKGROUND AND OBJECTIVES: Our goal was to determine the effect of temperature on the induction of tissue damage after laser-welded wound closure with and without albumin solder. STUDY DESIGN/MATERIALS AND METHODS: Multiple full-thickness skin incisions were made in a porcine model. Incisions were repaired by using a 1.32-microm laser at temperatures of 65 degrees C, 75 degrees C, 85 degrees C, or 95 degrees C with and without a 50% human albumin solder. The rate of apoptosis (programmed cell death) was quantified by counting the proportion of cells that stained positively for nuclear DNA fragmentation (nick end labeling). The distance that necrosis extended from the wound edge was also measured. The strength of the weld was measured with a tensiometer. RESULTS: For laser-welded repairs with solder, the amount of apoptosis at 65 degrees C and 75 degrees C was comparable to that of controls but became significantly elevated at 85 degrees C and 95 degrees C. The extent of necrosis was similar to that of controls at low temperature but also increased at 95 degrees C. Incisions repaired without solder showed increased necrosis compared with those repaired with solder at temperatures of 65 degrees C, 75 degrees C, and 95 degrees C at 0-0.5 mm from the incision. Wounds repaired at 85 degrees C and 95 degrees C showed more apoptosis in the absence of solder. The increased cell death at higher temperatures correlated with significantly decreased wound strengths at 3 days after repair in the solder group. A lower rate of cell death was observed in the solder group, which correlated with superior wound strength when compared with repairs without solder at days 0 (65-95 degrees C) and 3 (95 degrees C). CONCLUSION: Both apoptotic and necrotic cell death were used as quantitative measures of tissue injury and were accurate predictors of short-term wound strength. The addition of albumin solder decreased overall tissue injury. These results suggest that temperatures of 65-75 degrees C with solder provide the optimal conditions for maximizing acute wound strength and minimizing tissue injury.

Albumins↗
PubMed1999

Radiometric surface temperature measurements during dye-assisted laser skin closure: in vitro and in vivo results.

BACKGROUND AND OBJECTIVE: A thermal camera was used to measure surface temperatures during laser skin welding to provide feedback for optimization of the laser parameters. STUDY DESIGN/MATERIALS AND METHODS: Two-centimeter-long, full-thickness incisions were made in guinea pig skin in vitro and in vivo. India ink was applied to the incision edges, which were then mechanically apposed. Continuous-wave, 1.06-microm Nd:YAG laser radiation was scanned over the incisions, producing an effective pulse duration of approximately 100 msec. Cooling durations between scans of 1.6, 4.0, and 8.0 sec were studied in vitro. A 5-mm-diameter laser spot was used with the power kept constant at 10 W. Thermal images were obtained at 30 frames per second with a thermal camera detecting 3-5 microm radiation. Surface temperatures were recorded at 0, 1, and 6 mm from the center line of the incision. RESULTS/CONCLUSIONS: Cooling durations of 1.6 and 4.0 seconds in vitro resulted in temperatures at the weld site that remained above approximately 65 degrees C for prolonged periods of time. Cooling durations of 8.0 seconds were sufficient both in vitro and in vivo to prevent a significant rise in baseline temperatures at the weld site over time.

Animals↗
PubMed2000

Liver repair and hemorrhage control by using laser soldering of liquid albumin in a porcine model.

BACKGROUND AND OBJECTIVE: We evaluated laser soldering by using liquid albumin for welding liver injuries. Major liver trauma has a high mortality because of immediate exsanguination and a delayed morbidity from septicemia, peritonitis, biliary fistulae, and delayed secondary hemorrhage. STUDY DESIGN/MATERIALS AND METHODS: Eight laceration (6 x 2 cm) and eight nonanatomic resection injuries (raw surface, 6 x 2 cm) were repaired. An 805-nm laser was used to weld 50% liquid albumin-indocyanine green solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized and hepatic inflow occlusion was used for vascular control. All 16 soldering repairs were evaluated at 3 hours. RESULTS: All 16 laser mediated liver repairs had minimal blood loss as compared with the suture controls. No dehiscence, hemorrhage, or bile leakage was seen in any of the laser repairs after 3 hours. CONCLUSION: Laser fusion repair of the liver is a reliable technique to gain hemostasis on the raw surface as well as weld lacerations.

Albumins↗
PubMed2005

Potential occupational risks for neurodegenerative diseases.

BACKGROUND: Associations between occupations and neurodegenerative diseases (NDD) may be discernable in death certificate data. METHODS: Hypotheses generated from 1982 to 1991 study were tested in data from 22 states for the years 1992-1998. Specific occupations and exposures to pesticides, solvents, oxidative stressors, magnetic fields, and welding fumes were evaluated. RESULTS: About one third (26/87) of the occupations hypothesized with neurodegenerative associations had statistically significant elevated mortality odds ratios (MOR) for the same outcome. Occupations with the largest MORs were (a) for presenile dementia (PSD)-dentists, graders/sorters (non-agricultural), and clergy; (b) for Alzheimer's disease (AD)-bank tellers, clergy, aircraft mechanics, and hairdressers; (c) for Parkinson's disease (PD)-biological scientists, clergy, religious workers, and post-secondary teachers; and (d) for motor neuron disease (MND)-veterinarians, hairdressers, and graders and sorters (non-agricultural). Teachers had significantly elevated MORs for all four diseases, and hairdressers for three of the four. Non-horticultural farmers below age 65 had elevated PD (MOR = 2.23, 95% CI = 1.47-3.26), PSD (MOR = 2.22, 95% CI = 1.10-4.05), and AD (MOR = 1.76, 95% CI = 1.04-2.81). Sixty hertz magnetic fields exhibited significant exposure-response for AD and, below age 65, for PD (MOR = 1.87, 95% CI = 1.14-2.98) and MND (MOR = 1.63, 95% CI = 1.10-2.39). Welding had elevated PD mortality below age 65 (MOR = 1.77, 95% CI = 1.08-2.75). CONCLUSIONS: Support was observed for hypothesized excess neurodegenerative disease associated with a variety of occupations, 60 Hz magnetic fields and welding.

Adult↗
PubMed1993

Cancer in Illinois construction workers: a study.

A series of case-control studies using subjects from the Illinois State Cancer Registry have been conducted. Logistic regression was used to control for age and history of tobacco and alcohol use. Construction workers were consistently found to be younger than other subjects and to have used alcohol and tobacco more often. Significant positive associations between cancer of the stomach and welding (odds ratio [OR] = 2.11, 95% confidence interval [CI] = 1.09, 4.09), lung cancer and employment in the construction industry (OR = 1.18, 95% CI = 1.02, 1.26), and lung cancer and welding (OR = 1.68, 95% CI = 1.03, 2.76) were found. Significant negative associations between cancer of the colon and welding (OR = .54, 95% CI = .29, 1.00), cancer of the prostate and employment in the construction industry (OR = .76, 95% CI = .65, .89), cancer of the prostate and plumbing (OR = .44, 95% CI = .38, .50), cancer of the prostate and metal working (OR = .43, 95% CI = .19, .93), and bladder cancer and employment as an electrician (OR = .60, 95% CI = .36, 1.00) suggests that construction workers did not consistently experience excesses of cancers known to be associated with tobacco use, and an overall excess of sites not known to be related to tobacco use may have occurred.

Aged↗
PubMed1987

Large vessel sealing with the argon laser.

This study compared the histology, biochemistry, and tensile strength of laser-welded and sutured canine venotomies, arteriotomies, and arteriovenous fistulas. Twelve animals had bilateral femoral vessels studied, with one repair (control) closed with interrupted 6-0 polypropylene sutures, and the contralateral repair (experimental) welded with the argon laser. Specimens were examined at weekly intervals from 1 to 4 weeks (four animals for each type of repair), and were evaluated histologically by hematoxylin and eosin, elastin, and trichrome stains; biochemically by the formation of [3H]hydroxyproline as an index of collagen synthesis; and mechanically by tensile strength determinations. At removal, all experimental closures were patent without hematomas, aneurysms, or luminal dilatation. Histologic and biochemical examination and tensile strength determinations suggest that laser welding may be an alternative to sutures for repair of large-diameter venotomies, arteriotomies, and arteriovenous fistulas, as healing is comparable to that seen with suture repairs up to 4 weeks postoperatively.

Animals↗
PubMed2004

Albumin-genipin solder for laser tissue repair.

BACKGROUND: Laser tissue soldering (LTS) is an alternative technique to suturing for tissue repair that avoids foreign body reaction and provides immediate sealing of the wound. One of the major drawbacks of LTS, however, is the weak tensile strength of the solder welds when compared to sutures. In this study, a crosslinking agent of low cytotoxicity was investigated for its ability to enhance the bond strength of albumin solders with sheep intestine. STUDY DESIGN/MATERIALS AND METHODS: Solder strips were welded onto rectangular sections of sheep small intestine using a diode laser. The laser delivered in continuous mode a power of 170 +/- 10 mW at lambda = 808 nm, through a multimode optical fiber (core size = 200 microm) to achieve a dose of 10.8 +/- 0.5 J/mg. The solder thickness and surface area were kept constant throughout the experiment (thickness = 0.15 +/- 0.01 mm, area = 12 +/- 1.2 mm2). The solder was composed of 62% bovine serum albumin (BSA), 0.38% genipin, 0.25% indocyanin green dye (IG), and water. Tissue welding was also performed with a BSA solder without genipin, as a control group. The repaired tissue was tested for tensile strength by a calibrated tensiometer. Murine fibroblasts were also cultured in extracted media from heat-denatured genipin solder to assess cell growth inhibition in a 48 hours period. RESULTS: The tensile strength of the genipin solder was doubled that of the BSA solder (0.21 +/- 0.04 N and 0.11 +/- 0.04 N, respectively; P = 10(-15) unpaired t-test, N = 30). Media extracted from crosslinked genipin solder showed negligible toxicity to fibroblast cells under the culture conditions examined here. CONCLUSION: Addition of a chemical crosslinking agent, such as genipin, significantly increased the tensile strength of adhesive-tissue bonds. A proposed mechanism for this enhanced bond strength is the synergistic action of mechanical adhesion with chemical crosslinking by genipin.

Adhesives↗
PubMedDate not supplied

Investigation of corrosion and container integrity in metal food containers using scanning electron microscopy-X-ray microanalysis.

Scanning electron microscopy and x-ray microanalysis were used to investigate microleakage, two incidences of loss of coating integrity, filiform corrosion, and sulfide black corrosion in enamel-lined metal food containers. Microleakage developed in a canned cheese sauce at the side seam weld and was traced to a hot weld and a cold weld defect. An enamel-blistering problem developed in an aseptically processed milk-based product when the tinplate was heated above its melting point; the tin melted under the enamel coating, causing the blistering. An enamel-blistering problem, due to silicon contamination of the metal surface prior to enameling, developed on the bottom of a two-piece can that contained a chicken-based product. A sulfide black problem developed in canned clams, caused by scratches in the coating that were introduced during can manufacturing. A filiform corrosion problem developed on the outside of the easy score line of enameled tinplate lids with a light tin coating 0.08 microns thick.

Animals↗
PubMed1986

Cardiotoxic and bronchoconstrictor effects of industrial metal fumes containing barium.

For certain metal arc-welding and other metal processing operations, compounds of barium are used as flux components. Airborne fumes generated by welding with electrodes using barium fluoride or carbonate fluxes may contain 15-30% of barium in readily water-soluble form (Dare et al. 1984). Urine of welders inhaling such fumes was shown to contain elevated levels of barium ions (up to 234 micrograms/l). To assess the possible hazards of such exposure, the toxic potencies of fume samples, expressed in terms of their water-soluble barium ion contents, were compared with effects of solutions of barium salts in anaesthetised guinea-pigs. Dose-effect relationships were established and it was verified that acute toxic effects of inhaled aerosols or of intravenous bolus administration correlated with the barium contents of various forms of welding fumes. Bronchopulmonary reactivity to the barium was observed as marked increases in resistance to ventilatory air-flow, indicating bronchoconstriction. Simultaneously, marked pressor effects on blood pressure occurred. ECG abnormalities indicated myocardial hyperexcitability. Effects were modified by nifedipine and propranolol pretreatments.

Air Pollutants, Occupational↗
PubMed1991

CO2 and Nd:YAG laser systems in microsurgical venous anastomoses.

A comparative study was undertaken in 81 rats to investigate a CO2 and Nd:YAG laser system for laser-welded anastomosis of the femoral vein. Conventionally sutured anastomoses (CMSA) served as controls. Laser-welded anastomosis (LAMA) was easier and could be performed 30% faster than CMSA. Postoperative investigations included patency tests, postmortem examinations and light and electron microscopy. Aneurysms were not seen. Foreign-body reaction was more pronounced in CMSA. Patency rates for CO2-LAMA and CMSA were equal, whereas Nd:YAG-LAMA resulted in significantly higher rate of early postoperative thrombosis (P less than 0.01). Because of its physical properties, the CO2-laser system seems to be better suited for laser welding of delicate structures such as the rat femoral vein.

Anastomosis, Surgical↗
PubMed1983

Rare fracture of a total hip replacement.

Material fractures in the femoral part of total hip replacements, a late complication, are usually observed in the shaft. In our case, a fatigue fracture of the ball-neck weld occurred 8 1/2 years after implantation of the prosthesis because of insufficient weld depth. Additional negative factors proved to be varus implantation and overloading of the prosthesis due to obesity. The weld represented a point of low resistance. Even if major traumatic events are responsible for the fracture or loosening of an endoprosthesis, overloading (i.e., multiple "microtrauma") is also an important contributing factor.

Aged↗
PubMed1989

The effect of radiofrequency-generated thermal energy on the mechanical and histologic characteristics of the arterial wall in vivo: implications for radiofrequency angioplasty.

Abrupt reclosure of atherosclerotic vessels after percutaneous transluminal balloon angioplasty has been blamed on traumatic dissections and elastic recoil of the vessel wall. Thermal energy with compression produces fusion of separated arterial wall layers, and heat appears to alter the elastic recoil of the vessel wall. Radiofrequency (RF) thermal energy has been used to perform vascular anastomoses and thermal angioplasty. A simple in vivo experiment was designed to describe and quantitate vascular tissue weld strength produced by a range of RF thermal energy levels. Canine carotid arteries were compressed between a pair of modified bipolar forceps that applied RF energy, causing occlusive tissue welds between the apposed intimal surfaces. The strength of the welds was evaluated by measuring the perfusion pressure required to reopen the vessel lumen. A dosimetry range of 0 to 205 joules showed a typical dose-response curve for the relationship between energy applied and bond strength, plateauing at approximately 300 mm Hg. Light microscopy showed fusion of the inner surfaces of the vessel with preservation of vessel wall architecture. Additionally inflation of a bipolar RF balloon catheter in the normal canine carotid lumen produced an alteration of vessel profile angiographically and histologically. Results of these preliminary experiments suggest that balloon angioplasty with adjunctive RF thermal energy may have benefits in reducing the factors causing acute failure of conventional percutaneous transluminal balloon angioplasty.

Angiography↗