Hazards associated with blue light emitted during gas metal arc welding of mild steel using various shielding gases and currents.

Blue light emitted during arc welding is known to potentially cause photoretinopathy. To help prevent retinal injury, it is important to identify the hazards associated with various welding conditions. The present work conducted experiments involving gas metal arc welding of mild steel under various conditions, and measured the spectral radiance of the arcs. The effective radiance values, as used by the American Conference of Governmental Industrial Hygienists (ACGIH) to quantify exposure level of blue light, were subsequently calculated from the data. The resulting values were in the range of 5.0-118 W/cm2/sr, corresponding to hazardous levels according to ACGIH guidelines. The effective radiance was increased at higher welding currents and when pulsed currents were used rather than steady currents. The blue light hazard was also affected by the type of shielding gas employed. These data confirm that it is very hazardous to stare at arcs during gas metal arc welding of mild steel. As such, appropriate eye protection is necessary during arc welding, and directly staring at the arc should be avoided.

Clinical Features of Oral Multiple Primary Carcinomas Compared with Oral Single Primary Carcinoma.

BACKGROUND: Owing to the increase in the older population and the increased life span, the number of patients with oral multiple primary carcinomas will increase. Predicting the second and third carcinoma clinically is difficult, and the presence of second or third carcinomas is a factor that determines the prognosis of oral carcinoma. In this study, we examined the clinical features of oral multiple primary carcinomas treated in our department. METHODS: We retrospectively reviewed the medical records of patients with oral squamous cell carcinoma who underwent radical treatment at and were followed by the Department of Oral and Maxillofacial Surgery, Tottori University Hospital from January 2003 to October 2017. RESULTS: This study included 261 patients: 241 patients had oral single primary carcinoma and 20 patients had oral multiple primary carcinomas. Oral multiple primary carcinomas showed female predilection and occurred more frequently in the lower gingiva and significantly less frequently in the tongue (P < 0.01). Oral multiple primary carcinomas showed a significantly higher recurrence rate (P < 0.01). The 5-year overall survival of oral single primary carcinoma patients was 88.0% compared with 95% for oral multiple primary carcinomas, with no significant difference (log rank test, P = 0.54). However, the 15-year survival rate dropped to 28.1% in oral multiple primary carcinomas. The cumulative disease incidence rates of metachronous second primary carcinoma from first carcinoma at 5 years and 10 years were 3.45% and 5.36%, respectively. CONCLUSION: Oral multiple primary carcinomas rarely occur in the tongue. The 5-year survival rate showed no difference between single and multiple carcinoma patients, but over longer observation, the prognosis of multiple carcinoma was poor owing to a high recurrence rate. Because of the high recurrence rate and risk of further metachronous carcinoma in oral multiple primary carcinomas, longer-term follow-up is required.

Fume particle size distribution and fume generation rate during arc welding of cast iron.

This study measured the fume particle size distribution and fume generation rate during arc welding of cast iron and estimated the generation rate of respirable dust. In addition, the generation rate of particles with a diameter of 0.3 µm or less was estimated. In this experiment, three types of filler materials (mild steel wire, stainless steel wire, and mild steel covered electrodes) with main constituents of Fe or Fe-Cr-Ni, as proposed previously by the authors, were used. The welding methods were gas metal arc welding and shielded metal arc welding. The fumes measured in this research contained 73-91% respirable dust, and the fume generation rates were in the range of 1.96-12.2 mg/s. The results of this study were as follows: (i) the welding current affects the generation rate of respirable dust, and it is highly likely that the higher the fume generation rate, the more respirable dust is generated; (ii) the generation rates of respirable dust at low and high current were highest when mild steel covered electrodes and stainless steel wire was used, respectively; and (iii) the generation rate of particles with a diameter of 0.3 µm or less was highest when stainless steel wire is used.

Comprehensive analysis of hazard of ultraviolet radiation emitted during arc welding of cast iron.

OBJECTIVES: Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and skin erythema. The extent of the hazard of UVR varies depending on the welding process and conditions. Therefore, it is important to identify the levels of UVR present under different conditions. The purpose of this study was to investigate the degree of hazard of UVR emitted by the different types of arc welding of cast iron frequently used in industry. METHODS: In this study, we experimentally measured the UVR emitted during gas tungsten arc welding (GTAW), shielded metal arc welding (SMAW), and gas metal arc welding (GMAW) of cast iron. The degree of hazard of UVR was quantitatively evaluated in accordance with the guidelines of the American Conference of Governmental Industrial Hygienists. RESULTS: Effective irradiances measured in this study were in the range 0.045-2.2 mW/cm2 at a distance of 500 mm from the welding arc. The maximum allowable exposure times corresponding to these levels were only 1.4-67 s/day. CONCLUSIONS: UVR emitted during arc welding of cast iron has the following characteristics: (a) It is more hazardous at higher welding currents. (b) The magnitude of the hazard, which depends on the welding process, increases in the order of GMAW > SMAW > GTAW. (c) It is influenced by the filler material used; that is, the components contained in the filler material affect the hazard of UVR. The effect is Fe > Ni, Cr.

[A Case of Consciousness Disorder Induced by the Syndrome of Inappropriate Antidiuretic Hormone Secretion Following Cisplatin and 5-Fluorouracil Chemotherapy in a Patient with Tongue Cancer].

We herein report a case of a consciousness disorder that was induced by the syndrome of inappropriate antidiuretic hormone secretion following cisplatin (CDDP) and 5 -fluorouracil (5-FU) chemotherapy in a patient with tongue cancer. A 72- year-old woman complained of tongue pain and was admitted to our hospital for neoadjuvant chemotherapy, under a diagnosis of tongue squamous cell carcinoma (T4aN2bM0). She was treated with CDDP and 5-FU. On the second day after administration, she complained of nausea and anorexia, and on the third day, she showed impaired consciousness. Laboratory studies revealed that the patient had a serum sodium concentration 112mEq/L, and no dehydration was noted. The patient was diagnosed with SIADH, using the appropriate diagnostic criteria based on serum and urine hypoosmolality. We subsequently discontinued chemotherapy and initiated fluid restriction and sodium supplements. Two days after this treatment, her consciousness level improved, and on the fifth day of treatment, laboratory studies revealed a serum sodium level of 134mEq/ L.

Blue-Light Hazard From Gas Metal Arc Welding of Aluminum Alloys.

OBJECTIVES: The objective was to quantify the blue-light hazard from gas metal arc welding (GMAW) of aluminum alloys. The exposure level is expected to depend on the welding conditions. Therefore, it is important to identify the blue-light hazard under various welding conditions. METHODS: We experimentally conducted GMAW of aluminum alloys under various welding conditions and measured the spectral radiance of the arcs. The effective blue-light radiance, which the American Conference of Governmental Industrial Hygienists has defined to quantify the exposure level of blue light, was calculated from the measured spectral radiance. The maximum acceptable exposure duration per 10000 s for this effective blue-light radiance was calculated. RESULTS: The effective blue-light radiance measured in this study was in the range of 2.9-20.0 W cm-2·sr. The corresponding maximum acceptable exposure duration per 10000 s was only 5.0-34 s, so it is hazardous to view the welding arc. The effective blue-light radiance was higher at higher welding currents than at lower welding currents, when pulsed welding currents were used rather than steady welding currents, and when magnesium was included in the welding materials. CONCLUSIONS: It is very hazardous to view the arcs in GMAW of aluminum alloys. Welders and their helpers should use appropriate eye protection in arc-welding operations. They should also avoid direct light exposure when starting an arc-welding operation.

Hazard of ultraviolet radiation emitted in gas metal arc welding of mild steel.

OBJECTIVES: Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema in the workplace. The degree of hazard from UVR exposure depends on the welding method and conditions. Therefore, it is important to identify the UVR levels present under various conditions. METHODS: We experimentally evaluated the UVR levels emitted in gas metal arc welding (GMAW) of mild steel. We used both a pulsed welding current and a non-pulsed welding current. The shielding gases were 80% Ar + 20% CO2 and 100% CO2. The effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines was used to quantify the UVR hazard. RESULTS: The effective irradiance measured in this study was in the range of 0.51-12.9 mW/cm2 at a distance of 500 mm from the arc. The maximum allowable exposure times at these levels are only 0.23-5.9 s/day. CONCLUSIONS: The following conclusions were made regarding the degree of hazard from UVR exposure during the GMAW of mild steel: (1) It is more hazardous at higher welding currents than at lower welding currents. (2) At higher welding currents, it is more hazardous when 80% Ar + 20% CO2 is used as a shielding gas than when 100% CO2 is used. (3) It is more hazardous for pulsed welding currents than for non-pulsed welding currents. (4) It appears to be very hazardous when metal transfer is the spray type. This study demonstrates that unprotected exposure to UVR emitted by the GMAW of mild steel is quite hazardous.

Hazard of ultraviolet radiation emitted in gas tungsten arc welding of aluminum alloys.

Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema. The extent of the hazard of UVR varies depending on the welding method and conditions. Therefore, it is important to identify the levels of UVR that are present under various conditions. In this study, we experimentally evaluated the hazard of UVR emitted in gas tungsten arc welding (GTAW) of aluminum alloys. The degree of hazard of UVR is measured by the effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines. The effective irradiances measured in this study are in the range 0.10-0.91 mW/cm(2) at a distance of 500 mm from the welding arc. The maximum allowable exposure times corresponding to these levels are only 3.3-33 s/day. This demonstrates that unprotected exposure to UVR emitted by GTAW of aluminum alloys is quite hazardous in practice. In addition, we found the following properties of the hazard of UVR. (1) It is more hazardous at higher welding currents than at lower welding currents. (2) It is more hazardous when magnesium is included in the welding materials than when it is not. (3) The hazard depends on the direction of emission from the arc.

Diet supplementation with cholic acid promotes intestinal epithelial proliferation in rats exposed to γ-radiation.

Consumption of a high-fat diet increases some secondary bile acids (BAs) such as deoxycholic acid (DCA) in feces. DCA is derived from cholic acid (CA), a primary BA. We evaluated intestinal epithelial proliferation and BA metabolism in response to oral administration of cholic acid (CA) in rats to determine the influence of a CA diet on the responses of gut epithelia to γ-rays. WKAH/HkmSlc rats were divided into two dietary groups: control diet or CA-supplemented (2g/kg diet) diet. Some of the rats from each group were irradiated with γ-rays, and epithelial cell proliferation in the colon was analyzed histochemically. Unirradiated CA-fed rats had high levels of DCA and CA in the sera, as well as the presence of taurocholic acid in their feces. Significant increases were observed in both epithelial proliferation and the number of epithelial cells in the colon of the CA-fed rats, and this effect was observed at 8 weeks after γ-ray exposure. Furthermore, extracts from both cecal contents and sera of the unirradiated CA-fed rats promoted proliferation of IEC-6 cells. These results indicate that BAs in enterohepatic circulation promote proliferation and survival of the intestinal epithelium after receiving DNA damage.

Contribution of dipeptidyl peptidase IV to the severity of dextran sulfate sodium-induced colitis in the early phase.

Dipeptidyl peptidase IV (DPPIV) degrades some peptide hormones and cytokines, resulting in homeostatic modulation. However, the role of DPPIV in inflammatory bowel diseases remains controversial. To determine the role of DPPIV in colitis, we used F344/DuCrlCrlj (F344/Du) rats as a DPPIV-deficient model. The serum DPPIV activity was much lower in the F344/Du rats than in F344/Jcl rats which were used as a DPPIV-positive model. Interestingly, the disease activity index (DAI) was different in the early phase of 2% dextran sulfate sodium (DSS)-induced colitis, as judged by the mucosal myeloperoxidase activity, colonic weight, and cecal fermentation. Similarly, retarded DAI was apparent in the DPPIV-deficient rats with 1% DSS-induced colitis. These findings suggest that a low level of DPPIV activity contributed to maintaining intestinal homeostasis by suppressing the cleavage of cytokines and growth hormones in DSS-induced colitis, especially in the early phase of colitis and with moderate inflammation.

Cancer-associated fibroblasts and CD163-positive macrophages in oral squamous cell carcinoma: their clinicopathological and prognostic significance.

BACKGROUND: Stromal cells are believed to affect cancer invasion and metastasis. The purpose of this study was to evaluate the distribution of cancer-associated fibroblasts (CAFs) and the incidence of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC), focusing on clinicopathological factors and patient prognosis, as well as cancer invasion. METHODS: The study included 108 patients with OSCC. Anti-α-smooth muscle actin, CD68, and CD163 antibodies were used to identify CAFs and TAMs. CAFs were divided into 4 grades on the basis of staining intensity: negative (0), scanty (1), focal (2), and abundant (3). The most intensive areas of macrophage concentration in each tumor invasive stroma were also evaluated. RESULTS: The cancer specimens were divided into Grade 0/1, Grade 2, and Grade 3 on the basis of CAF grade. In addition, they were divided into low- and high-grade groups on the basis of the number of CD68-positive and CD163-positive macrophages. The latter were significantly increased in the Grade 2 CAF group compared to the Grade 0/1 group (P = 0.009). Kaplan-Meier and multivariate survival analyses revealed that Grade 2 CAFs (P = 0.003) and high CD163-positive macrophage levels (P = 0.007) significantly correlated with a poor outcome in patients with OSCC, and that a high CD163-positive macrophage level was a significant and an independent prognostic factor (P = 0.045). CONCLUSIONS: Cancer-associated fibroblasts and CD163-positive macrophages may be potential prognostic predictors of OSCC.

Zoledronic acid, a third-generation bisphosphonate, inhibits cellular growth and induces apoptosis in oral carcinoma cell lines.

Bisphosphonates (BPs) inhibit bone resorption by preventing osteoclast maturation and apoptosis induction. Recently, BPs have also been shown to have antitumor effects against various types of carcinomas in vitro and in vivo. In this study, we investigated the antitumor effect of zoledronic acid (ZOL), a third generation bisphosphonate, on proliferation, cell cycle and apoptosis of oral cancer cells. Direct antitumor effects of ZOL against four oral carcinoma cell lines (squamous cell carcinoma, HSC3, HSC4, SCCKN; salivary adenocarcinoma, HSY) were measured by WST assay. Apoptosis-related molecules were analyzed by Western blot analysis and cell cycle was analyzed by flow cytometry. ZOL had a dose-dependent antitumor effect in the four oral cancer cell lines. ZOL activated caspase-3, -8 and -9 and induced cellular apoptosis. Western blot analysis showed that ZOL increased cleaved anti-human poly(ADP-ribose) polymerase expression and decreased Bcl-2 and Bid expression. Treatment with ZOL increased the number of cells in apoptosis, sub G1 phase and S phase, and reduced the number of cells in the G0/G1 and G2/M phase in a concentration-dependent manner. ZOL inhibits cell proliferation and induces apoptosis of oral cancer cells in vitro. These findings suggest that ZOL might be beneficial in the treatment of oral carcinoma patients.

Novel rapid immunochromatographic test based on an enzyme immunoassay for detecting nucleocapsid antigen in SARS-associated coronavirus.

A novel severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been discovered. The detection of both antigens and antibodies in SARS-CoV from human specimens with suspected SARS plays an important role in preventing infection. We developed a novel rapid immunochromatographic test (RICT) based on the sandwich format enzyme immunoassay (EIA) with an all-in-one device for detecting the native nucleocapsid antigen (N-Ag) of SARS-CoV using monoclonal antibodies (MoAbs), which we produced by immunizing recombinant N-Ag to mice. RICT is a qualitative assay for respiratory aspirates and serum specimens. With this assay, a positive result can be judged subjectively by the appearance of a blue line on the device 15 min after the sample is applied. RICT with several pairs of MoAbs showed a high sensitivity for the detection of recombinant N-Ag as well as viral N-Ag of SARS-CoV. rSN122 and rSN21-2 were the best MoAbs for immobilized antibody and enzyme labeling, respectively. With regard to analytical sensitivity, RICT detected N-Ag at 31 pg/mL for recombinant N-Ag, and at 1.99 x 10(2) TCID(50)/mL for SARS-CoV. The specificity of RICT was 100% when 150 human sera and 50 nasopharyngeal aspirates (NSPs) were used. RICT based on an EIA using the rSN122/rSN21-2 pair is a sensitive, specific, and reliable rapid assay for detecting N-Ag in SARS-CoV treated with either heat or Triton X-100.

Thymosin-beta4 regulates motility and metastasis of malignant mouse fibrosarcoma cells.

We identified a thymosin-beta4 gene overexpression in malignant mouse fibrosarcoma cells (QRsP-30) that were derived from clonal weakly tumorigenic and nonmetastatic QR-32 cells by using a differential display method. Thymosin-beta4 is known as a 4.9-kd polypeptide that interacts with G-actin and functions as a major actin-sequestering protein in cells. All of the six malignant fibrosarcoma cell lines that have been independently converted from QR-32 cells expressed high levels of thymosin-beta4 mRNA and its expression in tumor cells was correlated with tumorigenicity and metastatic potential. Up-regulation of thymosin-beta4 in QR-32 cells (32-S) transfected with sense thymosin-beta4 cDNA converted the cells to develop tumors and formed numerous lung metastases in syngeneic C57BL/6 mice. In contrast, antisense thymosin-beta4 cDNA-transfected QRsP-30 (30-AS) cells reduced thymosin-beta4 expression, and significantly lost tumor formation and metastases to distant organs. Vector-alone transfected cells (32-V or 30-V cells) behaved like their parental cells. We observed that tumor cell motility, cell shape, and F-actin organization is regulated in proportion to the level of thymosin-beta4 expression. These findings indicate that thymosin-beta4 molecule regulates fibrosarcoma cell tumorigenicity and metastasis through actin-based cytoskeletal organization.