Metformin Reduces Bleomycin-induced Pulmonary Fibrosis in Mice

Metformin has anti-inflammatory and anti-fibrotic effects. We investigated whether metformin has an inhibitory effect on bleomycin (BLM)-induced pulmonary fibrosis in a murine model. A total of 62 mice were divided into 5 groups: control, metformin (100 mg/kg), BLM, and BLM with metformin (50 mg/kg or 100 mg/kg). Metformin was administered to the mice orally once a day from day 1. We sacrificed half of the mice on day 10 and collected the bronchoalveolar lavage fluid (BALF) from their left lungs. The remaining mice were sacrificed and analyzed on day 21. The right lungs were harvested for histological analyses. The messenger RNA (mRNA) levels of epithelial-mesenchymal transition markers were determined via analysis of the harvested lungs on day 21. The mice treated with BLM and metformin (50 mg/kg or 100 mg/kg) showed significantly lower levels of inflammatory cells in the BALF compared with the BLM-only mice on days 10 and 21. The histological examination revealed that the metformin treatment led to a greater reduction in inflammation than the treatment with BLM alone. The mRNA levels of collagen, collagen-1, procollagen, fibronectin, and transforming growth factor-β in the metformin-treated mice were lower than those in the BLM-only mice on day 21, although statistical significance was observed only in the case of procollagen due to the small number of live mice in the BLM-only group. Additionally, treatment with metformin reduced fibrosis to a greater extent than treatment with BLM alone. Metformin suppresses the inflammatory and fibrotic processes of BLM-induced pulmonary fibrosis in a murine model.

The Relationship Between Amalgam Tooth Fillings and Concentration of Blood Mercury in Elementary School Students in Korea / 대한산업의학회지

OBJECTIVES: The adverse health effects of mercury in dental amalgam have not yet been clarified. This study was conducted to examine the effects of dental amalgam on the concentration of blood mercury in Korean children. METHODS: A total of 1,275 students were enrolled in the elementary school in Seoul, Incheon, and Daegu. The number and location of dental amalgam filling of teeth were ascertained by oral examination. Dietary habits-including frequency of seafood intake-and other demographic factors were obtained from the children's parents. The concentration of blood mercury was measured by an atomic absorption spectrophotometer to which a hydride generator was installed. RESULTS: The geometric mean of blood mercury concentration was 1.91 microg/L. It was found that elementary school students in Seoul and the 4th grade elementary school students have the lowest concentration of blood mercury among the study groups. Both linear and secondary linear increase of the concentration of blood mercury, depending on the number of dental amalgam fillings, were statistically significant (p-trend < 0.01, p-quadratic < 0.01). As a result of multiple regression analysis on the blood mercury concentration of elementary school students, the regression coefficient (beta) of a dental amalgam filling was found to be 0.027 (standard error = 0.014, p = 0.048). CONCLUSIONS: In children, the dental amalgam fillings were significantly contribute to the concentration of blood mercury. To accurately assess the effect of dental amalgam on the concentration of body mercury, further studies using the concentration of urine mercury are needed.

Assessment of Acquired Color Vision Impairment in Inhalant Abusers / 대한산업의학회지

OBJECTIVES: This study was conducted in order to evaluate the effects of inhalants on color vision impairment. METHODS: The inhalation group consisted of 81 neurotoxic chemical substance abusers at Bugok National Hospital and Institute of Forensic Psychiatry, Ministry of Justice. The control group consisted of 41 employees of Bugok National Hospital. The Lanthony D-15 desaturated hue test was administered to both groups. For the qualitative analysis, we classified the results by the morphological characteristics of color vision impairment. For the quantitative analysis, we calculated the total color distance score (TCDS) and the color confusion index (CCI) and determined that the individual was abnormal if the TCDS was over 65.0 or the CCI was over 1.25. RESULTS: The TCDS of the inhalation group was 75.58+/-21.07 and the CCI was 1.34+/-0.37 in the right eye, and 75.47+/-23.63 and 1.34+/-0.42, respectively in the left eye. These results are higher than those found for the control group. In regards to the TCDS, 50 (61.8%) of the abusers in the inhalation group had color vision impairment in the right eye and 48 (59.2%) had impairment in the left eye. 11 (26.8%) of the employees in the control group had color vision impairment in the right eye and 13 (31.7%) had impairment in the left eye. In regards to the CCI, 38 (46.9%) of the abusers in the inhalation group had color vision impairment in the right eye and 35 (43.2%) had impairment in the left eye. 4 (9.8%) of the employees in the control group had color vision impairment in the right eye and 7 (17.0%) had impairment in the left eye. The results of multiple logistic regression analysis for acquired color vision impairment showed that the inhalation period (OR=1.20, 95% CI: 1.03~1.40) was the significant variable. CONCLUSIONS: These findings indicate that the inhalation of neurotoxic substances may impair the color vision, and the period inhaled with neurotoxic substances is significant variable affecting on the acquired color vision impairment.

Relation between Cyclooxygenase-2 and Polo-like Kinase-1 in Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: Elevated expression of cyclooxygenase-2 (COX-2) and Polo-like kinase-1 (PLK-1) is observed in a wide variety of cancers. Augmented expression of COX-2 and enhanced production of prostaglandin E2 (PGE2) are associated with increased tumor cell survival and malignancy; COX-2 has been implicated in the control of human non-small cell lung carcinoma (NSCLC) cell growth. PLK-1 siRNA induced the cell death of lung cancer cells and the systemic administration of PLK-1 siRNA/atelocollagen complex inhibited the growth of lung cancer in a liver metastatic murine model. COX-2 and PLK-1 are involved in proliferation and in cell cycle regulation, and there is a significant correlation between their interaction in prostate carcinoma. METHODS: In this study, we investigated the pattern of COX-2 and PLK-1 expression in NSCLC, after treatment with IL-1beta, COX-2 inhibitor and PLK-1 siRNA. RESULTS: Expression of PLK-1 was decreased in A549 COX-2 sense cells, and was increased in A549 COX-2 anti-sense cells. Knock out of PLK-1 expression by PLK-1 siRNA augmented COX-2 expression in A549 and NCl-H157 cells. When A549 and NCI-H157 cells were treated with COX-2 inhibitor on a dose-dependent basis, PLK-1 and COX-2 were reduced. However, when the expression of COX-2 was induced by IL-1beta, the production of PLK-1 decreased. CONCLUSION: These results demonstrate that COX-2 and PLK-1 are regulated and inhibited by each other in NSCLC, and suggest that these proteins have a reverse relationship in NSCLC.