The taxonomy of tapeworms belonging to the family Taeniidae has been controversial because of the paucity of adult phenotypic characters and the great plasticity of larvae in intermediate hosts. The ...family consists of the medically important two genera Echinococcus and Taenia, which are closely related to each other. Cladistic approaches using the molecular data of DNA and the numerical data of morphologic characters are clarifying phylogenetic relationships among the members of these genera. The nucleotide data of worldwide taeniid parasites accumulated in public DNA databases may provide a basis for the development of molecular diagnostic tools, and make it possible to identify the parasites, at least the human Taenia spp. by non-morphologists. Furthermore, the detection of intraspecific genetic variations prompts evolutionary and ecological studies to address fundamental questions of parasite distributional patterns. Here, we introduce the recent advances of taeniid phylogeny and its application to molecular diagnosis.
Purpose
In photon radiation therapy, computed tomography (CT) numbers are converted into values for mass density (MD) or relative electron density to water (RED). CT‐MD or CT‐RED calibration tables ...are relevant for human body dose calculation in an inhomogeneous medium. CT‐MD or CT‐RED calibration tables are influenced by patient imaging (CT scanner manufacturer, scanning parameters, and patient size), the calibration process (tissue‐equivalent phantom manufacturer, and selection of tissue‐equivalent material), differences between tissue‐equivalent materials and standard tissues, and the dose calculation algorithm applied; however, a CT number calibration audit has not been established. The purposes of this study were to develop a postal audit phantom, and to establish a CT number calibration audit process.
Methods
A conventional stoichiometric calibration conducts a least square fit of the relationships between the MD, material weight, and measured CT number, using two parameters. In this study, a new stoichiometric CT number calibration scheme has been empirically established, using three parameters to harmonize the calculated CT number with the measured CT number for air and lung tissue. In addition, the suitable material set and the minimal number of materials required for stoichiometric CT number calibration were determined. The MDs and elemental weights from the International Commission on Radiological Protection Publication 110 were used as standard tissue data, to generate the CT‐MD and CT‐RED calibration tables. A small‐sized, CT number calibration phantom was developed for a postal audit, and stoichiometric CT number calibration with the phantom was compared to the CT number calibration tables registered in the radiotherapy treatment planning systems (RTPSs) associated with five radiotherapy institutions.
Results
When a least square fit was performed for the stoichiometric CT number calibration with the three parameters, the calculated CT number showed better agreement with the measured CT number. We established stoichiometric CT number calibration using only two materials because the accuracy of the process was determined not by the number of used materials but by the number of elements contained. The stoichiometric CT number calibration was comparable to the tissue‐substitute calibration, with a dose difference less than 1%. An outline of the CT number calibration audit was demonstrated through a multi‐institutional study.
Conclusions
We established a new stoichiometric CT number calibration method for validating the CT number calibration tables registered in RTPSs. We also developed a CT number calibration phantom for a postal audit, which was verified by the performances of multiple CT scanners located at several institutions. The new stoichiometric CT number calibration has the advantages of being performed using only two materials, and decreasing the difference between the calculated and measured CT numbers for air and lung tissue. In the future, a postal CT number calibration audit might be achievable using a smaller phantom.
Anthropogenic ecosystem modification has affected over 80% of the global land cover. Interest in its effects on wildlife has been growing over the past several decades, specifically in regard to ...biodiversity and ecosystem function. Parasites are of particular interest, because they directly impact animal health, and can be transmitted to humans through the process of zoonosis. However, most studies so far tended to focus on only one or two parasites with few looking at the entire community, thereby limiting our understanding of the effects of ecosystem modification on parasitic organisms. In this study, we estimated the intestinal helminth diversity and species richness of the large Japanese field mouse (Apodemus speciosus), as well as the prevalence and abundance of each species in two modified ecosystems, a rural agricultural area and an urban park. We then compared them to a natural area to see how they have been altered. We found that diversity, prevalence, and abundance were all highly altered within both modified ecosystems, but generally to a greater degree within the urban park. However, there was great variation in the direction and degree of response of each helminth species, suggesting that generalized trends may be difficult to ascertain. Furthermore, it is important to analyze the entire helminth community, because interspecific interactions and the effect that ecosystem modification has on them may help determine what species persist.
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•Helminth community was compared between two modified ecosystems and a natural area.•Diversity, prevalence, and intensity were highly altered in modified ecosystems.•The response of each helminth species to ecosystem modification varied greatly.•Interaction between helminths may affect their response to eco-modification.
The genetic polymorphisms of
Echinococcus spp. in the eastern Tibetan Plateau and the Xinjiang Uyghur Autonomous Region were evaluated by DNA sequencing analyses of genes for mitochondrial cytochrome
...c oxidase subunit 1 (
cox1) and nuclear elongation factor-1 alpha (
ef1a). We collected 68 isolates of
Echinococcus granulosus sensu stricto (s.s.) from Xinjiang and 113 isolates of
E. granulosus s. s., 49 isolates of
Echinococcus multilocularis and 34 isolates of
Echinococcus shiquicus from the Tibetan Plateau. The results of molecular identification by mitochondrial and nuclear markers were identical, suggesting the infrequency of introgressive hybridization. A considerable intraspecific variation was detected in mitochondrial
cox1 sequences. The parsimonious network of
cox1 haplotypes showed star-like features in
E. granulosus s. s. and
E. multilocularis, but a divergent feature in
E. shiquicus. The
cox1 neutrality indexes computed by Tajima’s
D and Fu’s Fs tests showed high negative values in
E. granulosus s. s. and
E. multilocularis, indicating significant deviations from neutrality. In contrast, the low positive values of both tests were obtained in
E. shiquicus. These results suggest the following hypotheses: (i) recent founder effects arose in
E. granulosus and
E. multilocularis after introducing particular individuals into the endemic areas by anthropogenic movement or natural migration of host mammals, and (ii) the ancestor of
E. shiquicus was segregated into the Tibetan Plateau by colonising alpine mammals and its mitochondrial locus has evolved without bottleneck effects.
The aim of this study was to compare the quality of dynamic wave arc (DWA) and coplanar volumetric modulated arc therapy (co-VMAT) plans for the treatment of localized prostate cancer. The planning ...target volume (PTV)-rectum, a section of the PTV comprising the PTV minus that of the rectum, received 78 Gy in 39 fractions as the mean dose to the PTV-rectum. The DWA and co-VMAT plans were generated for each patient using the RayStation treatment planning system for the Vero4DRT system. The PTV-rectum dose (D
: the percent dose irradiating 95% of the volume), homogeneity index (HI), conformity index (CI), as well as doses to the bladder wall, rectum wall (V
Gy: the percent volume receiving 10-70 Gy), and bilateral femoral heads of the DWA and co-VMAT plans were compared. The output monitor unit (MU) and delivery time obtained for each set of plans were also investigated. In terms of target coverage, the DWA plans provided an average D
of 75.5 Gy, which was comparable to the co-VMAT-plan D
of 75.2 Gy (p < 0.05). The HI was significantly better with the DWA. As for the DWA plans, the bladder-wall volume receiving 10, 20, 30, and 40 Gy (V
) was significantly smaller than that of the co-VMAT plans, and the volume of the rectal wall receiving 10 Gy (V
) was significantly larger than that of the co-VMAT plans. The DWA plans yielded a reduced dose to the bilateral femoral heads compared with the co-VMAT plans (p < 0.05). The values of the CI and MU, and the delivery time exhibited no significant differences between the DWA and co-VMAT plans. The DWA plan is a feasible treatment option for prostate cancer radiotherapy.
A case of small bowel obstruction caused by Bolbosoma sp. infection is reported. A 27-year-old woman admitted with abdominal pain was diagnosed as small bowel obstruction. Laparoscopic surgery ...revealed induration in jejunum at ca. 120 cm distal to the ligament of Treiz, attributed to a band connecting the serosa to the ascending mesocolon. Resected band contained an acanthocephalan accompanying foreign body reaction with abscess formation. The parasite belonged to the genus Bolbosoma, of which identification was made by DNA sequence analysis. This is the eighth case of Bolbosoma infection in humans, and the first one causing an ileus.
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•Eighth human case of Bolbosoma infection.•First case causing ileus.•Identified based on DNA sequencing.
The cestode fauna of murid and cricetid rodents in Hokkaido, the northernmost island of Japan, was evaluated based on our parasite collection and a review of the literature. Adult and larval cestodes ...collected from Apodemus speciosus (Temminck, 1844), Myodes rufocanus (Sundevall, 1846), and Rattus norvegicus (Berkenhout, 1769) in Hokkaido were identified by both morphological and molecular diagnoses. A total of 10 species from 5 families were confirmed in our collection. Arostrilepis tenuicirrosa Makarikov, Gulyaev, and Kontrimavichus, 2011, Paranoplocephala kalelai (Tenora, Haukisalmi, and Henttonen, 1985), and Taenia crassiceps (Zeder, 1800) were recorded for the first time from Hokkaido. A comprehensive look at both the present and previous studies revealed that the cestode fauna of rodents in Japan consists of at least 30 species from 6 families. Among them, 23 species occur in Hokkaido. The species composition is strongly affected by the nearby Eurasian continent, suggesting parasite migrations with rodent hosts over land bridges between Hokkaido and Sakhalin and between Hokkaido and Honshu, the main island of Japan. A DNA barcoding system using sequences of nuclear 28S rDNA and mitochondrial cox1 allowed us to identify cestodes at species and genus levels, even in different developmental stages. The integration of morphological and molecular diagnoses is essential in cestode taxonomy to establish a common ground for biogeographical studies worldwide. The standardization of DNA barcoding is particularly of critical importance.
Lyme borreliosis (LB) is the most common vector‐borne disease in the Northern Hemisphere caused by spirochetes belonging to the Borrelia burgdorferi sensu lato (Bbsl) complex. Borrelia spirochetes ...circulate in obligatory transmission cycles between tick vectors and different vertebrate hosts. To successfully complete this complex transmission cycle, Bbsl encodes for an arsenal of proteins including the PFam54 protein family with known, or proposed, influences to reservoir host and/or vector adaptation. Even so, only fragmentary information is available regarding the naturally occurring level of variation in the PFam54 gene array especially in relation to Eurasian‐distributed species. Utilizing whole genome data from isolates (n = 141) originated from three major LB‐causing Borrelia species across Eurasia (B. afzelii, B. bavariensis, and B. garinii), we aimed to characterize the diversity of the PFam54 gene array in these isolates to facilitate understanding the evolution of PFam54 paralogs on an intra‐ and interspecies level. We found an extraordinarily high level of variation in the PFam54 gene array with 39 PFam54 paralogs belonging to 23 orthologous groups including five novel paralogs. Even so, the gene array appears to have remained fairly stable over the evolutionary history of the studied Borrelia species. Interestingly, genes outside Clade IV, which contains genes encoding for proteins associated with Borrelia pathogenesis, more frequently displayed signatures of diversifying selection between clades that differ in hypothesized vector or host species. This could suggest that non‐Clade IV paralogs play a more important role in host and/or vector adaptation than previously expected, which would require future lab‐based studies to validate.
Utilizing whole genome sequencing data for 141 Eurasian distributed Borrelia isolates, we show that the PFam54 gene array is highly variable among and within Borrelia species, including the absence of genes of known function during infection. Further analysis highlighted though that understudied paralogs most likely are important to completing the Borrelia life cycle, although with a yet unknown function, requiring further research. Taken together, the results display the importance of studying individual variation in Borrelia species from a population genetics perspective to provide novel hypotheses regarding Borrelia or vector‐borne pathogen evolution.
In the 1970’s and 1980’s, an unknown species of the genus Brachylaima (Trematoda: Brachylaimidae) had been recorded from the intestines of Rattus norvegicus and Apodemus speciosus in Hokkaido, Japan. ...The rodent fluke was characteristic in extending a bilateral vitellarium till the level of posterior margin of anterior testis and in keeping almost the same-sized spherical ovary and testes. In this study, the rodent fluke was rediscovered from A. speciosus, Apodemus argenteus, and Myodes rufocanus in Hokkaido. The resultant parasite collection enabled us to make a mitochondrial DNA (mtDNA) barcode for tracking its intermediate hosts. The metacercaria of the rodent fluke was detected frequently from the kidney of three species of land snails (Discus pauper, Succinea lauta, and Ainohelix editha). However, its sporocyst with cercariae was found only from the hepatopancreas of D. pauper, a fairly small snail. The wide-spectrum of the second intermediate host seems to increase the chance of transmitting the parasite to various mammals and birds. The use of indigenous land snails as the first and second intermediate hosts, the distinctiveness of the mtDNA sequence, and the characteristic morphology of all the developmental stages prompted us to propose Brachylaima asakawai sp. nov. for the rodent intestinal fluke in Hokkaido. The present field survey suggests that the life cycle of the new species is primarily dependent on a predator-prey relationship between rodents and D. pauper.
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•Brachylaima asakawai sp. nov. was described, together with ecological data.•Discus pauper acts as the first and second intermediate hosts, and voles and field mice serve as the definitive host.•The high variability of the parasite mtDNA indicates that the new species has evolved endemically in Hokkaido, Japan.
Abstract
We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MV X-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for ...lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D95%) to the PTV (1050 cGy × 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D99% doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D99% dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.
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