Genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food

AbstractHere, we conducted in vitro genotoxicity tests to evaluate the genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food. Styrene oligomers were extracted with acetone and the extract was subjected to the Ames test (OECD test guideline No. 471) and the in vitro chromosomal aberration test (OECD test guideline No. 473) under good laboratory practice conditions. The concentrations of styrene dimers and trimers in the concentrated extract were 540 and 13,431 ppm, respectively. Extraction with acetone provided markedly higher concentrations of styrene oligomers compared with extraction with 50% ethanol aqueous solution, which is the food simulant currently recommended for use in safety assessments of polystyrene by both the United States Food and Drug Administration and the European Food Safety Authority. And these high concentrations of styrene dimers and trimers were utilized for the evaluation of genotoxicity in vitro. Ames tests using five bacterial tester strains were negative both in the presence or absence of metabolic activation. The in vitro chromosomal aberration test using Chinese hamster lung cells (CHL/IU) was also negative. Together, these results suggest that the risk of the genotoxicity of styrene oligomers that migrate from polystyrene food packaging into food is very low

ダイチョウ ジョウヒ サイボウ ニ ハツゲン スル NADPH oxidase1 Nox1 ノ ブンシ トクセイ

NADPH oxidase 1 (Nox1) is an isozyme of gp91-phox predominantly expressed in the human colon. In this study, we have established primary cultures of guinea pig large intestinal epithelial cells (LIEC). A great majority of the cultured cells (>90%) was surface mucous cells containing periodic acid-Schiff reaction-positive granules. Vimentin-positive fibroblasts were <1%, and macrophages were not contaminated. LIEC spontaneously produced superoxide anion (O2 －) at about 160 nmol/mg protein/h. O2 －-dependent formation of blue formazan particles from nitroblue tetrazolium was observed only on surface of mucous-producing cells, and these cells expressed Nox1 protein at plasma membrane and in the cytoplasm. They expressed p67-phox, p22-phox, and rac1, but not gp91-phox, p47-phox, p40-phox, and rac 2. Immunohistochemistry showed that Nox1, p 67-phox, and p 22-phox were predominantly expressed in surface mucous cells of human and guinea pig colonic mucosa. Human colon cancer cell lines (Caco2, T84, and HT29 cells) expressed Nox1, p22-phox, and rac1, but not the other NADPH components. These cells secreted O2 － at <5 nmol/mg protein/h. Caco2 cells possessed Toll-like receptor 5, and flagellin (FliC) from Salmonella enteritidis phosphorylated transforming growth factor-β-activated kinase 1 (TAK1) and TAK1-binding protein 1, and significantly up-regulated O2 － production. These results suggest that Nox1 expressed in colonic epithelial cells may regulate interactions between pathogenic bacteria and epithelial cells for host defense

Signaling pathway for phagocyte priming upon encounter with apoptotic cells

The phagocytic elimination of cells undergoing apoptosis is an evolutionarily conserved innate immune mechanism for eliminating unnecessary cells. Previous studies showed an increase in the level of engulfment receptors in phagocytes after the phagocytosis of apoptotic cells, which leads to the enhancement of their phagocytic activity. However, precise mechanisms underlying this phenomenon require further clarification. We found that the pre-incubation of a Drosophila phagocyte cell line with the fragments of apoptotic cells enhanced the subsequent phagocytosis of apoptotic cells, accompanied by an augmented expression of the engulfment receptors Draper and integrin αPS3. The DNA-binding activity of the transcription repressor Tailless was transiently raised in those phagocytes, depending on two partially overlapping signal-transduction pathways for the induction of phagocytosis as well as the occurrence of engulfment. The RNAi knockdown of tailless in phagocytes abrogated the enhancement of both phagocytosis and engulfment receptor expression. Furthermore, the hemocytespecific RNAi of tailless reduced apoptotic cell clearance in Drosophila embryos. Taken together, we propose the following mechanism for the activation of Drosophila phagocytes after an encounter with apoptotic cells: two partially overlapping signal-transduction pathways for phagocytosis are initiated; transcription repressor Tailless is activated; expression of engulfment receptors is stimulated; and phagocytic activity is enhanced. This phenomenon most likely ensures the phagocytic elimination of apoptotic cells by stimulated phagocytes and is thus considered as a mechanism to prime phagocytes in innate immunity. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.Embargo Period 12 month

Quantitative and Qualitative Urinary Cellular Patterns Correlate with Progression of Murine Glomerulonephritis

The kidney is a nonregenerative organ composed of numerous functional nephrons and collecting ducts (CDs). Glomerular and tubulointerstitial damages decrease the number of functional nephrons and cause anatomical and physiological alterations resulting in renal dysfunction. It has recently been reported that nephron constituent cells are dropped into the urine in several pathological conditions associated with renal functional deterioration. We investigated the quantitative and qualitative urinary cellular patterns in a murine glomerulonephritis model and elucidated the correlation between cellular patterns and renal pathology

Medical and nursing interventions influence a caregiver’s willingness to continue home hemodialysis: a multicenter cross-sectional survey

Abstract Background In Japan, home hemodialysis (HHD) has several benefits, including a favorable prognosis, enhanced quality of life (QOL) of patients, and cost-effectiveness. However, the caregiver’s burden in assisting patients on HHD is significant, which influences their decision to continue HHD. This study focused on the relationship between medical and nursing interventions, caregiver resolve to continue HHD, and caregiver quality of life, aiming to create support strategies for caregivers. Methods A multicenter cross-sectional survey was conducted on caregivers of patients on HHD from 150 HHD facilities in Japan. The caregiver’s intent to continue HHD was assessed using a four-tier response scale that evaluated aspects such as caregiver–healthcare provider meetings, caregiver breaks, treatment discussions, difficulty in HHD initiation, and post-initiation medical support. Caregiver QOL was evaluated using the Short-form Health Survey, eight domains (SF-8). Statistical analysis involved χ-squared tests, independent t-tests, and propensity score matching. Results The study achieved a caregiver participation rate of 55.6%. Results indicated that caregivers who were inclined to continue HHD were significantly more likely to receive respite outpatient dialysis and had a better understanding of HHD mechanics as explained by healthcare professionals; however, propensity score matching revealed limited generalizability. There was no significant difference in the SF-8 scores before and after propensity score matching among the groups. Conclusions This study highlights that there are a small number of caregivers who have little motivation to continue HHD and emphasizes the crucial role of support from healthcare professionals. Comprehensive support, including respite dialysis and detailed HHD information, may affect HHD sustainability

Effects of the lateral growth rate on wood quality of Gmelina arborea from 3.5-, 7- and 12-year-old plantations

• Awareness of the shortage of fossil resources leads to an increasing demand for woody biomass. We investigated the feasibility of using fast-growing Gmelina arborea wood for material production. Gmelina arborea wood samples were collected from trees of varying cambium ages in Indonesia, from 3.5-, 7- and 12-year-old plantations. • The lateral growth rate and the cambium age did not significantly affect the longitudinal released strain of the growth stress, xylem density, or microfibril angle at the outermost surface of the secondary xylem at any sampling site. However, fiber length in the 3.5-year-old plantation tended to be shorter in smaller diameter trees, whereas in larger diameter trees it was almost the same as that in trees from the 7- and 12-year-old plantations. This suggests that smaller diameter trees in the 3.5-year-old plantation had not yet produced mature wood. • Xylem qualities had already reached values appropriate for harvesting, except in the smaller diameter trees from the 3.5-year-old plantation. This indicates that the larger diameter trees had already matured, regardless of their cambium age. These results suggest that the next step is to develop silvicultural treatments to increase the lateral growth rate during the early growing stage, in order to produce as much mature wood as possible, as quickly as possible.Effet du taux radial de croissance sur la qualité du bois de Gmelina arborea provenant de plantations de 3,5, 7 et 12 ans. • La prise de conscience de la raréfaction des ressources fossiles conduit à une demande croissante de biomasse ligneuse. Dans ce contexte nous avons examiné la faisabilité d'utiliser une essence à croissance rapide Gmelina arborea pour la production de bois matériau$.$Nous avons collecté en Indonésie des échantillons de bois dans des arbres provenant de plantations de 3,5, 7 et 12 ans. • Pour tous les sites, le taux de croissance radiale et l'âge cambial n'affectent pas les déformations résiduelles longitudinales des contraintes de croissance, la densité du xylème ou l'angle des microfibrilles de la périphérie du xylème secondaire. Cependant pour les petits arbres de la plantation de 3,5 ans, les fibres sont plus courtes tandis que pour les gros arbres les fibres ont une longueur comparable à celle des arbres des plantations de 7 et 12 ans. Cela suggère que les petits arbres de la plantation de 3,5 ans ne produisent pas encore du bois mature. • Les qualités du xylème ont facilement atteint des valeurs justifiant l'exploitation exception faite des petits arbres de la plantation de 3,5 ans. Cela indique que les gros arbres sont déjà matures indépendamment de leur âge. Ces résultats suggèrent que l'étape suivante est le développement de traitements sylvicoles visant à augmenter le taux de croissance radiale durant le stade initial de croissance, dans le but de produire le plus rapidement possible le plus de bois adulte