Characterization of transgenic pigs that express human decay accelerating factor and cell membrane-tethered human tissue factor pathway inhibitor.

The expression of human complement regulatory proteins (hCRP; hDAF, hCD59, and hMCP) in pig tissues has been suggested as one of strategies to overcome the hyperacute rejection (HAR) in pig-to-human transplantation. Expression of human tissue factor pathway inhibitor (hTFPI) in porcine endothelial cells has been suggested as a remedy to overcome microvascular thrombosis. To investigate the effects of these combined transgenes, we established transformed pig cells expressing human decay accelerating factor (hDAF) under the control of enhancer promoter (5'LTR-PCMVIE), and the fusion protein (hTFPI/hCD4) consisting of the functional domains (K1 and K2) of hTFPI and membrane-tethering domains (D3 and D4) of hCD4 under the control of PCMVIE. Transgenic pigs were generated with the transformed porcine cells through somatic cell nuclear transfer (SCNT) technology. Analysis of quantitative PCR and real-time quantitative RT-PCR showed that four copies of hDAF were integrated and 391 copies of hDAF mRNA expressed in the cells of the transgenic pig. The enhancing activity of 5'LTR was approximately 2 fold compared to CMVIE promoter only. The cell viability test showed that more than 80% of ear cells were viable in the presence of 50% human serum. The chromogenic substrate assay and immunocytochemical staining with tail cells showed that the TFPI activity of fusion protein was observed on the cell membrane. The membrane localization of hDAF and hTFPI proteins was observed by immunocytochemical staining, and the expression of transgenes in heart and liver tissues was also confirmed by immunohistochemistry.

Effects of combined expression of human complement regulatory proteins and H-transferase on the inhibition of complement-mediated cytolysis in porcine embryonic fibroblasts.

The expression of human complement regulatory proteins (CRP) and H-transferase (HT) in porcine cells is one of the strategies for suppression of hyperacute rejection (HAR) of xenotransplants in human recipients. In this study, we investigated the inhibitory effect of combined expression of human complement regulators and HT on human serum-mediated cytolysis in porcine embryonic fibroblasts. For the combinated expression of human CRPs in transformed pig cells, cDNAs of human DAF, MCP, and CD59 were cloned into the same insertional plasmid under the control of pCMV IE and LTR. The double combination of CRPs, hDAF-hMCP, and hMCP-hCD59 survived over 50% in the presence of 50% human serum, compared to the control. Moreover, the cell viability was increased more than 65% and 80% in the combination of human DAF-CD59 and DAF-MCP-CD59, respectively. In addition, the combination of HT gene to hDAF-hCD59 vector increased the viability close to 80%, similar to the triple combination of CRPs. These observations suggest that the combined expression of human CRPs and HT in the same insertional vector may be more effective in protecting porcine cells from human complement-mediated cytolysis.

Antioxidative effects of 7-hydroxy-3-methoxy-cadalene extracted from Zelkova serrata on 4-(methylinitros amino)-1-(3-pyridyl)-1-butanone-induced oxidative stress in A/J mice.

Effects of 7-hydroxy-3-methoxy-cadalene (cadalene) extracted from Zelkova serrata on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced oxidative stress were examined using A/J mice. NNK (65 microg/ml water) was orally administered to 20 mice for 7 weeks, followed by free feeding of a commercial diet, not containing cadalene, for 2 weeks. The control group was maintained without NNK and cadalene administration, and treatment groups with NNK and cadalene (6.25, 25, 100 mg/kg feed) feeding for 25 weeks. The glutathione concentration of cadalene-treated (65 microg/ml water) group was significantly higher than that of the group treated only with NNK (p < 0.05). The results of our study strongly indicate that cadalene exerts antioxidative effect on NNK-induced lung tumorigenesis in A/J mice.

Reduction of hexavalent chromium collected on PVC filters.

Chromium exists at various valences, including elemental, trivalent, and hexavalent chromium, and undergoes reduction-oxidation reactions in the environment. Since hexavalent chromium is known as a human carcinogen, it is most important to evaluate the oxidation-reduction characteristics of the hexavalent chromium species. Although hexavalent chromium can be reduced to trivalent state, the detailed information on this in workplace environments is limited. The purpose of this study was to investigate hexavalent chromium reduction in time in various conditions. A pilot chrome plating operation was prepared and operated in a laboratory for this study. There was evidence that the hexavalent chromium was reduced by time after mist generation. The percentage ratio (with 95% confidence intervals in parentheses) of hexavalent chromium to total chromium was almost 100% (99.1 approximately 102.3) immediately after mist generation, and was reduced to 87.4% (84.8 approximately 89.9) at 1 hour and 81.0% (78.3 approximately 83.5) at 2 hours, respectively. Another test indicated that hexavalent chromium collected on PVC filters was also reduced by time after sampling. Hexavalent chromium was reduced to 90.8% (88.2 approximately 93.3) at 2 hours after sampling. It also was found that hexavalent chromium was reduced during storage in air. It is recommended that air samples of hexavalent chromium be protected against reduction during storage.

Analysis of some metabolites of organic solvents in urine by high-performance liquid chromatography with beta-cyclodextrin.

Chromatographic separation of the metabolites derived from toluene, ethylbenzene, styrene and xylene was carried out on untreated urine samples from factory workers. The elution sequence was as follows: phenylglyoxilic acid, 3-hydroxy-2-butanone, hippuric acid, o-methylhippuric acid, p-methylhippuric acid, m-methylhippuric acid, p-cresol, m-cresol and o-cresol. The stability constants (K(G)) of cresol and methylhippuric acid derivatives were evaluated. The capacity factor (k'), selectivity factor (alpha) and resolution (Rs) are described with a variety of mobile phases containing beta-cyclodextrin (beta-CD). The optimum concentration ratio of ethanol-water-acetic acid-beta-CD was determined to be 20:80:0.3:1.4%. Under these conditions, k' values of the five metabolites were 2

Quality control for industrial hygiene laboratories.

In the Republic of Korea a quality control programme has been introduced for industrial hygiene laboratories responsible for monitoring chemicals in working environments. Its development is outlined below.

Patch test responses to rockwool of different diameters evaluated by cutaneous blood flow measurement.

Rockwool is a man-made mineral fiber used mainly for insulation, which can cause mechanical skin irritation. This study was performed to evaluate the irritant potential of rockwools of different diameters and to compare the change of blood flow, measured by laser Doppler flowmetry, at different patch test occlusion times with rockwools. Rockwool A (mean diameter 4.20 +/- 1.96 mu) was more irritating than rockwool B (mean diameter 3.20 +/- 1.5 mu). The difference was more clearly observed in a 48-h patch test than in an 8-h or 24-h test. We concluded that laser Doppler blood flow measurement was a useful experimental tool for the evaluation of irritant patch test responses to mechanical irritants like rockwool, and that 48 h or more of occlusion time was necessary to produce irritant patch test responses to certain types of rockwool.

A comparison of iron oxide fume inside and outside of welding helmets.

A study was conducted to compare the iron oxide fume concentrations inside and outside the helmets of welders. Airborne iron oxide fume concentrations were determined simultaneously at four body locations--the left front shoulder, right front shoulder, front chest, and inside the helmet--during welders' normal activity. Results indicate that the fume concentrations at the actual breathing zone inside helmets are reduced to 36%-71% of concentrations outside the helmets, depending on the type of welding and employees' postures.

Worker exposure to asbestos during removal of sprayed material and renovation activity in buildings containing sprayed material.

Contents and types of asbestos in fireproofing insulation materials sprayed on ceilings of 127 buildings throughout the U.S. were studied. Asbestos was found to be present in more than 50% of the buildings and chrysotile was the main component identified. Frequency distribution of airborne fiber concentrations was lognormal. During renovation activities by various workers, including sheet-metal workers, carpenters and electricians, average fiber concentrations at workers' breathing zones were less than 2 fibers/cc, but exceeded 0.1 fibers/cc. During removal of sprayed materials, workers were exposed to extremely high concentrations (average 16.4 fibers/cc) when dry methods were used. When wet methods were used during removal, the airborne fiber concentrations were sharply reduced to less than 2 fibers/cc.