Modeling of body tissues for Monte Carlo simulation of radiotherapy treatments planned with conventional x-ray CT systems

In the conventional procedure for accurate Monte Carlo simulation of radiotherapy, a CT number given to each pixel of a patient image is directly converted to mass density and elemental composition using their respective functions that have been calibrated speci cally for the relevant x-ray CT system. We propose an alternative approach that is a conversion in two steps: the rst from CT number to density and the second from density to composition. Based on the latest compilation of standard tissues for reference adult male and female phantoms, we sorted the standard tissues into groups by mass density and de ned the representative tissues by averaging the material properties per group. With these representative tissues, we formulated polyline relations between mass density and each of the following; electron density, stopping-power ratio and elemental densities. We also revised a procedure of stoichiometric calibration for CT-number conversion and demonstrated the two-step conversion method for a theoretically emulated CT system with hypothetical 80 keV photons. For the standard tissues, high correlation was generally observed between mass density and the other densities excluding those of C and O for the light spongiosa tissues between 1.0 g cm−3 and 1.1 g cm−3 occupying 1% of the human body mass. The polylines tted to the dominant tissues were generally consistent with similar formulations in the literature. The two-step conversion procedure was demonstrated to be practical and will potentially facilitate Monte Carlo simulation for treatment planning and for retrospective analysis of treatment plans with little impact on the management of planning CT systems

Cystic echinococcosis : Future perspectives of molecular epidemiology

Human cystic echinococcosis (CE) has been considered to be caused predominantly by Echinococcus granulosus sensu stricto (the dog-sheep strain). Molecular approaches' on CE, however, have revealed that human cases are also commonly caused by another species, Echinococcus canadensis. All indices for classification and standardization of CE pathology including available images, epidemiology, diagnostics and treatment are currently based largely on a mixture of infections which include at least E. granulosus s.s. and E. canadensis. Involvement of other species of Echinococcus in CE including E. ortleppi or otherwise cryptic diversity demonstrated recently in Africa requires further elucidation. Molecular identification of the causative species in CE cases is essential for better understanding of pathogenesis and disease. This article stresses the importance of molecular species identification of human CE as a foundation for re-evaluation of evidence-based epidemiology. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

Estimation of organ doses and effective doses in image－guided respiration-gated radiotherapy.

13301甲第4301号博士（保健学）金沢大学博士論文要旨Abstract 以下に掲載：Radiation Protection Dosimetry Epub ahead of print pp.1-9 2015. Oxford University Press. 共著者：Minoru Nakao, Satoshi Obara, Kuniaki Nabatame, Keiichi Akahane, Shigeru Sanada, Toshiyuki Shira

Quantitative environmental DNA metabarcoding shows high potential as a novel approach to quantitatively assess fish community

水に含まれる環境DNAから「どんな魚」が「どれだけいるか」を同時に推定 --定量的な魚類群集モニタリングを容易に実現--. 京都大学プレスリリース. 2023-01-20.The simultaneous conservation of species richness and evenness is important to effectively reduce biodiversity loss and keep ecosystem health. Environmental DNA (eDNA) metabarcoding has been used as a powerful tool for identifying community composition, but it does not necessarily provide quantitative information due to several methodological limitations. Thus, the quantification of eDNA through metabarcoding is an important frontier of eDNA-based biomonitoring. Particularly, the qMiSeq approach has recently been developed as a quantitative metabarcoding method and has attracted much attention due to its usefulness. The aim here was to evaluate the performance of the qMiSeq approach as a quantitative monitoring tool for fish communities by comparing the quantified eDNA concentrations with the results of fish capture surveys. The eDNA water sampling and the capture surveys using the electrical shocker were conducted at a total of 21 sites in four rivers in Japan. As a result, we found significant positive relationships between the eDNA concentrations of each species quantified by qMiSeq and both the abundance and biomass of each captured taxon at each site. Furthermore, for seven out of eleven taxa, a significant positive relationship was observed between quantified DNA concentrations by sample and the abundance and/or biomass. In total, our results demonstrated that eDNA metabarcoding with the qMiSeq approach is a suitable and useful tool for quantitative monitoring of fish communities. Due to the simplicity of the eDNA analysis, the eDNA metabarcoding with qMiSeq approach would promote further growth of quantitative monitoring of biodiversity

Echinococcus felidis in hippopotamus, South Africa

Hydatid cysts of Echinococcus felidis are described from the hippopotamus (Hippopotamus amphibius) from Mpumalanga Province, South Africa. Among six hippopotami investigated, hepatic hydatids were found in three. The identification was based on mitochondrial and nuclear DNA sequences. In addition, the rostellar hook morphology was analysed. This is the first morphological description of the metacestode of E. felidis, and the first molecularly confirmed report of the intermediate host of E. felidis in South Africa. The definitive host of E. felidis in South Africa is the lion (Panthera leo).Peer reviewe

Rapid diagnosis of lyme disease: Flagellin gene-based nested polymerase chain reaction for identification of causative Borrelia species

AbstractObjective: Each of Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii has characteristic restriction sites in its flagellin gene. The authors focused on this gene and developed a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for rapid diagnosis of Lyme disease.Methods: External and internal primer sets were designed for nested PCR to amplify an approximately 580 by fragment of the flagellin gene that includes species-specific restriction sites. DNA extracted from tissue samples of mice and humans were used as templates for PCR. The amplicons obtained were digested with HapII, HhaI, CelII HincII, or Ddel endonuclease.Results: In mice experimentally infected with each of B. burgdorferi sensu stricto, B. garinii, and B. afzelii, borrelial DNA was detected irrespective of differences in the causative species. However, RFLP of the amplicons was able to identify the species. Skin biopsy samples from 11 Japanese patients with erythema migrans were subjected to both PCR and culture tests. Borrelial infections were detected in seven cases (64%) by PCR and eight cases (73%) by culture. All PCR-positive samples were also positive by culture. The causative species in human infections was easily identified as B. garinii by RFLP analysis of the amplicons.Conclusion: The nested PCR-RFLP system appears to be an easy and reliable diagnostic tool for the detection and species identification of borreliae in human cutaneous biopsies

Cryptic diversity in hymenolepidid tapeworms infecting humans

An adult hymenolepidid tapeworm was recovered from a 52-year-old Tibetan woman during a routine epidemiological survey for human taeniasis/cysticercosis in Sichuan, China. Phylogenetic analyses based on sequences of nuclear 28S ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 showed that the human isolate is distinct from Hymenolepis diminuta and Hymenolepis nana, the common parasites causing human hymenolepiasis. Proglottids of the human isolate were unfortunately unsuitable for morphological identification. However, the resultant phylogeny demonstrated the human isolate to be a sister species to Hymenolepis hibernia from Apodemus mice in Eurasia. The present data clearly indicate that hymenolepidid tapeworms causing human infections are not restricted to only H. diminuta and H. nana.Peer reviewe

Echinococcus vogeli Infection in a Hunter, French Guiana

Echinococcus vogeli infection in a hunter from the rain forest of French Guiana was confirmed by imaging and mitochondrial DNA sequence analysis. Serologic examination showed typical patterns for both alveolar and cystic echinococcosis. Polycystic echinococcis caused by E. vogeli may be an emerging parasitic disease in Central and South America

Description and life-cycle of Taenia lynciscapreoli sp n. (Cestoda, Cyclophyllidea)

A new species of tapeworm, Taenia lynciscapreoli sp. n. (Cestoda, Cyclophyllidea), is described from the Eurasian lynx (Lynx lynx), the main definitive host, and the roe deer (Capreolus capreolus and C. pygargus), the main intermediate hosts, from Finland and Russia (Siberia and the Russian Far East). The new species was found once also in the wolf (Canis lupus) and the Eurasian elk/moose (Alces alces), representing accidental definitive and intermediate hosts, respectively. The conspecificity of adult specimens and metacestodes of T. lynciscapreoli sp. n. in various host species and regions, and their distinction from related species of Taenia, was confirmed by partial nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 gene. Morphologically, T. lynciscapreoli sp. n. can be separated unambiguously from all other species of Taenia by the shape of its large rostellar hooks, particularly the characteristically short, wide and strongly curved blade. If the large rostellar hooks are missing, T. lynciscapreoli may be separated from related species by a combination of morphological features of mature proglottids. It is suggested that T. lynciscapreoli has been present in published materials concerning the tapeworms of L. lynx and L. pardinus in Europe, but has been misidentified as Taenia pisiformis (Bloch, 1780). Taenia lynciscapreoli sp. n. has not been found in lynx outside the range of roe deer, suggesting a transmission pathway based on a specific predator-prey relationship. The present study applies a novel, simple approach to compare qualitative interspecific differences in the shape of rostellar hooks.Peer reviewe