Pyruvate remediation of cell stress and genotoxicity induced by haloacetic acid drinking water disinfection by‐products

Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by‐products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA‐mediated inhibition of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration‐dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) >> chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA‐induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the S_N2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. Environ. Mol. Mutagen. 54:629–637, 2013. © 2013 Wiley Periodicals, Inc.     

Diffuse Ependymal Dysembryoplastic Neuroepithelial Tumor Causing Spinal Drop Metastases: A Case Report

Dysembryoplastic neuroepithelial tumors (DNETs) arise mostly in the supratentorial cerebral cortex. A very rare case of intraventricular DNET with diffuse ependymal involvement, which causes spinal drop metastasis, is presented.     

Various tumors in the nasal vestibule

Various types of diseases can involve the nasal vestibule. Diagnosis and treatment of a nasal vestibular mass is often challenging due to the anatomical features of the nasal vestibule. Here, we present four cases with nasal vestibular masses. Two cases were diagnosed as squamous papillomas. The others were a trichofolliculoma and pseudoepitheliomatous hyperplasia with hyperkeratosis. Our aim was to discuss the characteristics of each disease and the considerations thought to be necessary for diagnosis and treatment of nasal vestibular tumors from these cases and the related literature.     

Inhibition of STAT3 signaling and induction of SHP1 mediate antiangiogenic and antitumor activities of ergosterol peroxide in U266 multiple myeloma cells

Background  

Ergosterol peroxide (EP) derived from edible mushroom has been shown to exert anti-tumor activity in several cancer cells. In the present study, anti-angiogenic activity of EP was investigated with the underlying molecular mechanisms in human multiple myeloma U266 cells.     

Body Fat Assessment Method Using CT Images with Separation Mask Algorithm

In recent years, the number of obese population in Korea has been growing up along with the economic development, environmental factors, and the change in life style. Considering the growth of obese population and the adverse effect of obesity on health, it is getting more important to prevent and diagnose the obesity with the quantitative measurement of body fat that has become an important indicator for obesity. In this study, we proposed a procedure for the automated fat assessment from computed tomography (CT) data using image processing technique. The proposed method was applied to a single-CT image as well as CT-volume data, and results were correlated to those of dual-energy X-ray absorptiometry (DEXA) that is known as the reliable method for evaluating body fat. Using single-CT images, correlation coefficients between DEXA and the automated assessment and DEXA and the manual assessment were 0.038 and 0.058, respectively (P > 0.05). Hence, there was no significant correlation between three methods using the proposed method with single-CT images. On the other hand, in case of CT-volume data, the above correlation coefficients were increased to 0.826, 0.812, and 0.805, respectively (P < 0.01). Thus, DEXA and the proposed methods with CT-volume data showed highly significant correlation with each other. The results suggest that the proposed automated assessment using CT-volume data is a reliable method for the evaluation of body fat. It is expected that the clinical application of the proposed procedure will be helpful to reduce the time for the quantitative evaluation of patient’s body fat.     

Effects of strobe light stimulation on postnatal developing rat retina

The nature and intensity of visual stimuli have changed in recent years because of television and other dynamic light sources. Although light stimuli accompanied by contrast and strength changes are thought to have an influence on visual system development, little information is available on the effects of dynamic light stimuli such as a strobe light on visual system development. Thus, this study was designed to evaluate changes caused by dynamic light stimuli during retinal development. This study used 80 Sprague-Dawley rats. From eye opening (postnatal day 14), half of the rats were maintained on a daily 12-h light/dark cycle (control group) and the remaining animals were raised under a 12-h strobe light (2 Hz)/dark cycle (strobe light-reared group). Morphological analyses and electroretinogram (ERG) were performed at postnatal weeks 3, 4, 6, 8, and 10. Among retinal neurons, tyrosine hydroxylase-immunoreactive (TH-IR, dopaminergic amacrine cells) cells showed marked plastic changes, such as variations in numbers and soma sizes. In whole-mount preparations at 6, 8, and 10 weeks, type I TH-IR cells showed a decreased number and larger somata, while type II TH-IR cells showed an increased number in strobe-reared animals. Functional assessment by scotopic ERG showed that a-wave and b-wave amplitudes increased at 6 and 8 weeks in strobe-reared animals. These results show that exposure to a strobe light during development causes changes in TH-IR cell number and morphology, leading to a disturbance in normal visual functions.