Measurement of 2,4-toluene diisocyanate concentrations by different samplers.

The standard sampling methods for toluene diisocyanate (TDI) only collect total TDI without separating the aerosol and gas phases. There are few other samplers, such as the dual filter, triple filter and annular denuder systems (ADS), which are able to sample the aerosol and gas phases simultaneously. This field study was conducted at two workplaces to access the total 2,4-TDI and the gaseous and aerosol TDI concentrations by different samplers simultaneously. In addition to the standard sampling time of 15 min, sampling was done for 30 and 60 min to study the effect of sampling time on the measured 2,4-TDI concentrations. Test results at two workplaces show that gas-phase 2,4-TDI is the predominant species and the aerosol phase concentration is very small. The measurements using various samplers show that the sampling time influences the sampled TDI concentration considerably which may be due to reaction of TDI with water vapor and polyo in the sampling process. It is evident that as sampling time increases the TDI concentration decreases. Laboratory test was also conducted using pure gas-phase 2,4-TDI to confirm the sampling time effect on the measured concentrations found in the field study.

Exposure assessment of organic solvents for aircraft paint stripping and spraying workers.

The main objective of this study is to investigate the personal or area exposure of organic solvents during paint stripping and paint spraying. Three aircraft paint stripping/spraying workplaces in Taiwan were selected, and the Council of Labor Affairs and NIOSH recommended sampling/analytical methods used in this study. Activated charcoal tubes were used to investigate the personal and area exposure concentration of organic solvents in paint stripping and paint spraying operations. During aircraft paint stripping, experiment results show that methylene chloride personal exposure concentration at the ground area, 42.01+/-31.86 ppm, is higher than that at the working platform 4 M high above the ground, 20.41+/-11.43 ppm. Exposure concentration of methylene chloride in the initial paint stripping operation stage of every workplace is over the PEL (50 ppm) set by the Taiwan Council of Labor Affairs. Corrective actions are needed. During paint spraying, concentrations of all organic solvents were found to be below the PEL of OSHA.

Lack of expression of the Epstein-Barr Virus (EBV) gene products, EBERs, EBNA1, LMP1, and LMP2A, in breast cancer cells.

Epstein-Barr virus (EBV), a gamma herpesvirus, has been associated with a variety of human malignancies such as Burkitt's lymphoma, Hodgkin's lymphoma, NPC, and gastric cancer. A controversy regarding the association of EBV with breast cancers has recently been reported in the literature. These reports have mainly used the DNA detection techniques of polymerase chain reaction and Southern blot hybridization, with the inherent lacunae associated with these techniques for signal localization. Our group has studied EBV association with breast cancer by using in situ hybridization for detecting nonpolyadenylated EBV RNA (EBERs), along with using protein localization technique of immunohistochemistry, studying the EBV nuclear antigen 1 (EBNA1) and the latent membrane proteins (LMP1 and LMP2A). This is the first article analyzing the expression of LMP2A in breast cancer cells. In all of our 43 female breast cancer cases under study, we failed to detect expression of any of the EBV viral gene products tested.

Expression of Das-1 in primary lung adenocarcinomas represents reactivation of an oncofetal pulmonary antigen.

OBJECTIVE: The monoclonal antibody (mAb) designated as mAb Das-1 was generated against a colonic epithelial protein. It reacts with bronchiolar epithelium and submucosal glands and weakly with alveolar lining cells of fetal lung. Adult alveolar epithelium is, however, nonreactive for mAb Das-1. The present study was designed to evaluate the immunoexpression of Das-1 and to correlate it with the histomorphology of primary lung adenocarcinomas and intestinal metaplasia. METHODS: Eighty-four cases of primary lung adenocarcinomas were reviewed and categorized according to histologic grade and subtype. Immunohistochemical staining with mAb Das-1 was performed with normal colon as control. RESULTS: Expression of Das-1 in the submucosal bronchial glands also served as internal control. Strong and diffuse staining was seen in 33 of the 84 cases of adenocarcinomas (39%). CONCLUSIONS: Expression of Das-1 was seen in primary lung adenocarcinomas even though adult alveolar epithelium is negative. Staining with mAb Das-1 was seen regardless of the grade or histological subtype of the lung adenocarcinomas. As most primary lung adenocarcinomas are not of bronchial gland origin, expression of Das-1 represents activation of oncofetal antigens.

Effect of interferon-alpha on CD20 antigen expression of B-cell chronic lymphocytic leukemia.

Chimeric CD20 monoclonal antibody as alternative therapy in relapsed low-grade non-Hodgkin's lymphoma (NHL) has produced responses in nearly 50% of patients. Augmenting CD20 expression on tumor cells and/or inducing its expression may increase the cell kill and effectiveness of antibody therapy. Peripheral blood lymphocytes from 19 patients with B-cell chronic lymphocytic leukemia (B-CLL) were incubated in vitro in the presence of interferon-alpha (IFN-alpha) (500 U/ml and 1,000 U/ml) for 24 and 72 hours. The effect on CD20 expression was studied by flow cytometry. The differences in the percentage positivity, the mean fluorescence intensity (MFI), and the product of percentage positivity and MFI were used to assess upregulation. There was a significant upregulation of CD20 expression on B cells seen at both concentrations after 24-hour priming (p < 0.01). B-CLL cells cultured for 72 hours in the presence of IFN-alpha also showed upregulation of CD20 expression; however, the degree of upregulation was much lower than that seen at 24 hours. There was no statistically significant increase in CD20 antigen expression on normal lymphocytes following cytokine exposure. These results suggest that IFN-alpha priming may augment the effectiveness of antibody therapy by directly upregulating CD20 antigen expression in addition to its indirect action through effector cells of the host.

Tumor necrosis factor modulates CD 20 expression on cells from chronic lymphocytic leukemia: a new role for TNF alpha?

Tumor necrosis factor alpha (TNF alpha) is a pleiotropic cytokine that is constitutively produced by leukemic cells in B Chronic Lymphocytic Leukemia (B-CLL). It has been shown to have autocrine and paracrine functions in normal B cells and in B lymphoproliferative diseases. This study was conducted to determine the effect of TNF alpha (in vitro) on CD20 expression on cells from patients with B-CLL. Currently, anti-CD20 monoclonal antibody therapy is becoming a second line treatment in the management of B cell disorders like low-grade non-Hodgkin's lymphoma (NHL) and B-CLL. Our results demonstrate amply that very low doses of TNF alpha (0. 0125 ng/ml) can be used to significantly increase CD20 expression on cells from patients of B-CLL as evidenced by increases in both percentage positivity and mean fluorescence intensity. The upregulation is evident as early as 24 hours and is maintained for up to 72 hours. We propose that the upregulation is a direct result of in vitro differentiation stimulated by TNF alpha. The results presented can be exploited in the designing of priming protocols prior to antibody therapy and this is discussed.