53 research outputs found

    Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

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    The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. The large Japanese field mice (Apodemus speciosus) are rodents endemic to, and distributed throughout, Japan. This wild rodent live in and around the ex-evacuation zone on the ground surface and/or underground. In this study, we evaluated the effect of chronic radiation exposure associated with FDNPP accident on the testes of large Japanese field mice. Morphological analysis and electron-prove X-ray microanalysis (EPMA) was undertaken on the testes. Morphological analysis of testes based on H&E staining showed that the spermatogenesis was observed normally in the breeding season of wild mice in the heavily contaminated area. However, caesium (Cs) was not detected in all testes of wild mice from FDNPP ex-evacuation zone. In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, we could not detect radiation effects on the spermatogenesis and Cs in the examined large Japanese field mice testes following chronic radiation exposure associated with the FDNPP accident

    Intestinal Bacteria as Powerful Trapping Lifeforms for the Elimination of Radioactive Cesium

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    In March 2011, an accident at the Fukushima Daiichi Nuclear Power Plant led to major problems, including the release of radionuclides such as Cesium (Cs)-137 into the environment. Ever since this accident, Cs-137 in foods has become a serious problem. In this study, we determined the concentration of Cs-137 in the feces, urine, and ruminal contents of cattle and demonstrated the possibility of its elimination from the body by intestinal bacteria. The results revealed a high Cs-137 concentration in the feces; in fact, this concentration was higher than that in skeletal muscles and other samples from several animals. Furthermore, intestinal bacteria were able to trap Cs-137, showing an uptake ratio within the range of 38–81% in vitro. This uptake appeared to be mediated through the sodium–potassium (Na+-K+) ion pump in the bacterial cell membrane. This inference was drawn based on the fact that the uptake ratio of Cs-137 was decreased in media with high potassium concentration. In addition, it was demonstrated that intestinal bacteria hindered the trapping of Cs-137 by the animal. Cattle feces showed high concentration of Cs-137 and intestinal bacteria trapped Cs-137. This study is the first report showing that intestinal bacteria contribute to the elimination of Cs-137 from the body

    Purification of enzymatically inactive peptidylarginine deiminase type 6 from mouse ovary that reveals hexameric structure different from other dimeric isoforms

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    The murine peptidylarginine deiminase (PAD) has five isoforms encoded by different genes and partici- pates in a variety of cellular functions through the citrullination of target proteins. The crystal structure of human PAD4 with a dimeric form was previously solved because of the enzyme’s relevance to rheuma- toid arthritis. PAD6, abundant in mouse oocytes and eggs, is believed to take part in early events of embryogenesis, but its biochemical properties are little understood. Here we have purified and charac- terized a recombinant PAD6. A PAD6 cDNA was cloned from mouse ovary RNA and expressed in Escherichia coli through pET29 and pGEX vectors. When benzoyl-L-arginine ethyl ester was used as a substrate, no appreciable activity was detected with a cell homogenate under conditions where a human PAD4 cDNA caused significant activity. Both pro- teins were affinity-purified to near homogeneity. The circular dichroism spectra of PAD6 and human PAD4 were similar in the far ultraviolet region. On molecular sieving, PAD6 was eluted faster than human PAD4. The cross-linking of PAD6 with dime- thyl suberimidate clearly showed six bands on an sodium dodecyl sulfate-polyacrylamide gel. These results indicate that PAD6 can constitute a hexameric structure. The purified PAD6 still showed no enzy- matic activity. This unique structure and loss in enzymatic activity is strongly suggested to favor the formation of egg cytoplasmic sheets as the architectu- ral protein

    Automatic Determination of the Center of Macular Hole Using Optical Coherence Tomography En Face Images

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    To evaluate the automated determination of the center of an idiopathic macular hole (MH) by using swept-source optical coherence tomography (OCT) images with new macro-based algorithms in ImageJ and to compare the difference between the MH center measurements obtained automatically and manually. This cross-sectional study included 39 eyes of 39 elderly individuals (22 women, 17 men) with stage 3 and 4 MH. The MH center was automatically determined using the ImageJ macro. The foveal center was also manually identified by two masked examiners using horizontal and vertical serial B-scan OCT angiography images. The mean age was 68.8 ± 8.3 years. After adjusting for the effect of magnification, the mean distance between the MH center determined manually by Examiner 1 and that determined automatically was 15.5 ± 9.9 µm. The mean distance between the two manually determined measurements of the MH center was 20.3 ± 19.7 µm. These two mean distance values did not differ significantly (Welch t-test, p = 0.27) and was non-inferior (p < 0.0001). The automated ImageJ-based method for determining the MH center was comparable to manual methods. This study showed that automated measurements were non-inferior to manual measurements, and demonstrated a substitutable usefulness, at least for use in clinical practice

    Structure-Dependent Effects of Bisphosphonates on Inflammatory Responses in Cultured Neonatal Mouse Calvaria

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    Bisphosphonates (BPs) are classified into two groups, according to their side chain structures, as nitrogen-containing BPs (NBPs) and non-nitrogen-containing BPs (non-NBPs). In this study, we examined the effects of NBPs and non-NBPs on inflammatory responses, by quantifying the inflammatory mediators, prostaglandin E2 (PGE2) and nitric oxide (NO), in cultured neonatal mouse calvaria. All examined NBPs (pamidronate, alendronate, incadronate, risedronate, zoledronate) stimulated lipopolysaccharide (LPS)-induced PGE2 and NO production by upregulating COX-2 and iNOS mRNA expression, whereas non-NBPs (etidronate, clodronate, tiludronate) suppressed PGE2 and NO production, by downregulating gene expression. Additionally, [4-(methylthio) phenylthio] methane bisphosphonate (MPMBP), a novel non-NBP with an antioxidant methylthio phenylthio group in its side chain, exhibited the most potent anti-inflammatory activity among non-NBPs. Furthermore, results of immunohistochemistry showed that the nuclear translocation of NF-κB/p65 and tyrosine nitration of cytoplasmic protein were stimulated by zoledronate, while MPMBP inhibited these phenomena, by acting as a superoxide anion (O2−) scavenger. These findings indicate that MPMBP can act as an efficacious agent that causes fewer adverse effects in patients with inflammatory bone diseases, including periodontitis and rheumatoid arthritis
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