Publications by authors named "Hiroki Kawai"

73 Publications

Machine learning approach for discrimination of genotypes based on bright-field cellular images.

NPJ Syst Biol Appl 2021 07 21;7(1):31. Epub 2021 Jul 21.

Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, 135-0064, Japan.

Morphological profiling is a combination of established optical microscopes and cutting-edge machine vision technologies, which stacks up successful applications in high-throughput phenotyping. One major question is how much information can be extracted from an image to identify genetic differences between cells. While fluorescent microscopy images of specific organelles have been broadly used for single-cell profiling, the potential ability of bright-field (BF) microscopy images of label-free cells remains to be tested. Here, we examine whether single-gene perturbation can be discriminated based on BF images of label-free cells using a machine learning approach. We acquired hundreds of BF images of single-gene mutant cells, quantified single-cell profiles consisting of texture features of cellular regions, and constructed a machine learning model to discriminate mutant cells from wild-type cells. Interestingly, the mutants were successfully discriminated from the wild type (area under the receiver operating characteristic curve = 0.773). The features that contributed to the discrimination were identified, and they included those related to the morphology of structures that appeared within cellular regions. Furthermore, functionally close gene pairs showed similar feature profiles of the mutant cells. Our study reveals that single-gene mutant cells can be discriminated from wild-type cells based on BF images, suggesting the potential as a useful tool for mutant cell profiling.
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http://dx.doi.org/10.1038/s41540-021-00190-wDOI Listing
July 2021

Rituximab Was Effective for Treatment of Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Early Adolescence in Initially Suspected Dissociative Disorder.

Clin Neuropharmacol 2021 May-Jun 01;44(3):99-100

Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama.

Objectives: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an increasingly recognized etiology of psychiatric symptoms. Because patients with anti-NMDAR encephalitis frequently show aggression, mania, hallucination, depression, or delusion, they are initially diagnosed with schizophrenia or mood disorders. There is only 1 case report of an initially diagnosed dissociative disorder.

Methods: We obtained consent for the presentation and have not identified individuals for ethical reasons.

Results: We first report an adolescent female patient with anti-NMDAR encephalitis who was initially suspected of having dissociative disorder but was responsive to immunotherapies including rituximab. In this case, her symptoms and electroencephalogram findings were proportional to the antibody titer in the cerebrospinal fluid.

Conclusions: It is important to consider the possibility of autoimmune encephalitis and immunotherapy including rituximab in cases of not only acute psychosis but also dissociation.
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http://dx.doi.org/10.1097/WNF.0000000000000443DOI Listing
February 2021

Clinical evaluation of childhood cerebral adrenoleukodystrophy with balint's symptoms.

Brain Dev 2021 Mar 11;43(3):396-401. Epub 2020 Dec 11.

Division of Clinical Genetics, Gifu University Hospital, Gifu, Japan; Division of Genomics Research, Life Science Research Center, Gifu University, Gifu, Japan.

Background: Childhood cerebral adrenoleukodystrophy (CCALD) is the most common phenotype of adrenoleukodystrophy (ALD) and is characterized by the progression of intellectual, psychic, visual, and gait disturbances. Progression of this intractable disease can only be prevented by hematopoietic stem cell transplantation during the early stages of the disease. The aim of this study was to clinically evaluate children with CCALD who have visual symptoms to enable early diagnosis.

Methods: We enrolled 41 Japanese children with CCALD who had visual symptoms. We retrospectively analyzed age of onset, past medical history, initial symptoms, visual symptoms and findings on brain magnetic resonance imaging.

Results: The median age of disease onset was 7 years (range 5-10 years). The most common visual symptom was strabismus (n = 22). There was only one patient with the triad of symptoms of Balint's syndrome. Seventeen patients had incomplete Balint's syndrome and showed one or two of the triad of symptoms. Almost all patients with complete or incomplete Balint's syndrome showed bilateral parieto-occipital white matter lesions.

Conclusions: CCALD could develop into Balint's syndrome, especially the incomplete form. Therefore, CCALD should be considered when boys show new symptoms, including lack of eye contact or bumping into objects.
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http://dx.doi.org/10.1016/j.braindev.2020.11.010DOI Listing
March 2021

The Effect of GD1a Ganglioside-Expressing Bacterial Strains on Murine Norovirus Infectivity.

Molecules 2020 Sep 7;25(18). Epub 2020 Sep 7.

Department of Frontier Sciences for Advanced Environment, Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.

In this study, we investigated the impact of GD1a-expressing bacterial strains on the infectivity of murine norovirus (MNV). Eligible bacterial strains were screened from a sewage sample using flow cytometry, and their genetic sequences of 16S rRNA were determined. The enzyme-linked immunosorbent assay (ELISA) was employed to analyze the binding between bacteria and MNV particles, and the plaque assay was used to assess the effects of GD1a-positive and negative strains on MNV infectivity. The result from ELISA shows that MNV particles are able to bind to both GD1a-positive and negative bacterial strains, but the binding to the GD1a-positive strain is more significant. The infectivity assay result further shows that the MNV infectious titer declined with an increasing concentration of GD1a-positive bacteria. The addition of anti-GD1a antibody in the infectivity assay led to the recovery of the MNV infectious titer, further confirming that the binding between MNV particles and bacterial GD1a ganglioside compromises MNV infectivity. Our findings highlight the role indigenous bacteria may play in the lifecycle of waterborne enteric viruses as well as the potential of exploiting them for virus transmission intervention and water safety improvement.
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http://dx.doi.org/10.3390/molecules25184084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571017PMC
September 2020

Assessment of dysplasia in bone marrow smear with convolutional neural network.

Sci Rep 2020 09 7;10(1):14734. Epub 2020 Sep 7.

Department of Hemato-Oncology, International Medical Center, Saitama Medical University, Saitama, Japan.

In this study, we developed the world's first artificial intelligence (AI) system that assesses the dysplasia of blood cells on bone marrow smears and presents the result of AI prediction for one of the most representative dysplasia-decreased granules (DG). We photographed field images from the bone marrow smears from patients with myelodysplastic syndrome (MDS) or non-MDS diseases and cropped each cell using an originally developed cell detector. Two morphologists labelled each cell. The degree of dysplasia was evaluated on a four-point scale: 0-3 (e.g., neutrophil with severely decreased granules were labelled DG3). We then constructed the classifier from the dataset of labelled images. The detector and classifier were based on a deep neural network pre-trained with natural images. We obtained 1797 labelled images, and the morphologists determined 134 DGs (DG1: 46, DG2: 77, DG3: 11). Subsequently, we performed a five-fold cross-validation to evaluate the performance of the classifier. For DG1-3 labelled by morphologists, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 91.0%, 97.7%, 76.3%, 99.3%, and 97.2%, respectively. When DG1 was excluded in the process, the sensitivity, specificity, PPV, NPV, and accuracy were 85.2%, 98.9%, 80.6%, and 99.2% and 98.2%, respectively.
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http://dx.doi.org/10.1038/s41598-020-71752-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7477564PMC
September 2020

Mechanism of action of a T cell-dependent bispecific antibody as a breakthrough immunotherapy against refractory colorectal cancer with an oncogenic mutation.

Cancer Immunol Immunother 2021 Jan 14;70(1):177-188. Epub 2020 Jul 14.

Division of Developmental Therapeutics, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan.

T cell-dependent bispecific antibody (TDB)-induced T cell activation, which can eliminate tumor cells independent of MHC engagement, is expected to be a novel breakthrough immunotherapy against refractory cancer. However, the mechanism of action of TDBs has not been fully elucidated thus far. We focused on TDB-induced T cell-tumor cell contact as an important initial step in direct T cell-mediated tumor cell killing via transport of cytotoxic cell proteases (e.g., granzymes) with or without immunological synapse formation. Using an anti-EGFR/CD3 TDB, hEx3, we visualized and quantified T cell-tumor cell contact and demonstrated a correlation between the degree of cell contact and TDB efficacy. We also found that cytokines, including interferon-gamma (IFNγ) and tumor necrosis factor-alpha (TNFα) secreted by activated T cells, damaged tumor cells in a cell contact-independent manner. Moreover, therapeutic experiences clearly indicated that hEx3, unlike conventional anti-EGFR antibodies, was effective against colorectal cancer (CRC) cells with mutant KRAS, BRAF, or PIK3CA. In a pharmacokinetic analysis, T cells spread gradually in accordance with the hEx3 distribution within tumor tissue. Accordingly, we propose that TDBs should have four action steps: 1st, passive targeting via size-dependent tumor accumulation; 2nd, active targeting via specific binding to tumor cells; 3rd, T cell redirection toward tumor cells; and 4th, TDB-induced cell contact-dependent (direct) or -independent (indirect) tumor cell killing. Finally, our TDB hEx3 may be a promising reagent against refractory CRC with an oncogenic mutation associated with a poor prognosis.
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http://dx.doi.org/10.1007/s00262-020-02667-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7838078PMC
January 2021

Application of accelerated long-range corrected exchange functional [LC-DFT(2Gau)] to periodic boundary condition systems: CO adsorption on Cu(111) surface.

J Chem Phys 2020 Mar;152(10):104105

RIKEN Center for Computational Science, 7-1-26, Minatojima-Minami-Machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.

Several different types of density functional theory (DFT) exchange correlation functionals were applied to a periodic boundary condition (PBC) system [carbon monoxide (CO) adsorbed on Cu(111): CO/Cu(111)] and the differences in the results calculated using these functionals were compared. The exchange correlation functionals compared were those of Perdew-Burke-Ernzerhof (PBE) and those of long-range corrected density functional theory (LC-DFT), such as LC-ωPBE(2Gau) and LC-BLYP(2Gau). Solid state properties such as the partial density of states were calculated in order to elucidate the detailed adsorption mechanisms and back-bonding peculiar to the CO/Cu(111) system. In addition, our benchmark analysis of the correlations among the orbitals of CO and Cu metal using LC-DFT reasonably was in line with the experimentally observed adsorption site. The computation time was reasonable, and other numerical results were found to agree well with the experimental results and also with the theoretical results of other researchers. This suggests that the long-range Hartree-Fock exchange integral should be included to correctly predict the electronic nature of PBC systems.
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http://dx.doi.org/10.1063/1.5141919DOI Listing
March 2020

Anti-NMDA-receptor antibody in initial diagnosis of mood disorder.

Eur Neuropsychopharmacol 2019 09 26;29(9):1041-1050. Epub 2019 Jul 26.

Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.

Anti-NMDAR encephalitis is increasingly recognized as one etiology of psychiatric symptoms, but there is not enough evidence on patients with mood disorder. We assayed anti-NR1/NR2B IgG antibodies in serum and/or cerebrospinal fluid of 62 patients initially diagnosed with mood disorder by a cell-based assay. We also investigated the specific patient characteristics and psychotic symptoms. At first admission, the patients showed only psychiatric symptoms without typical neurological signs or abnormal examination findings. Four of the 62 patients had anti-NR1/NR2B IgG antibodies. The anti-NR1/NR2B IgG antibody-positive patients showed more super- or abnormal sensitivity (P = 0.00088), catatonia (P = 0.049), and more conceptual disorganization (P < 0.0001), hostility (P = 0.0010), suspiciousness (P < 0.0001), and less emotional withdrawal (P < 0.0001) and motor retardation (P < 0.0001) on the Brief Psychiatric Rating Scale than the antibody-negative patients. During the clinical course, anti-NR1/NR2B IgG antibody-positive patients showed more catatonia (P = 0.0042) and met Graus's criteria for diagnosis of anti-NMDAR encephalitis, but negative patients did not. Immunotherapy was effective for anti-NR1/NR2B IgG antibody-positive patients, and there was the weak relationship (R² = 0.318) between the anti-NR1/NR2B IgG antibody titer in the cerebrospinal fluid and the Brief Psychiatric Rating Scale score.
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http://dx.doi.org/10.1016/j.euroneuro.2019.07.137DOI Listing
September 2019

Anti-N-Methyl-D-Aspartate Receptor Encephalitis in Psychiatry.

Acta Med Okayama 2019 Jun;73(3):189-195

Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558,

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a recently-discovered autoimmune disorder in which antibodies target NMDAR in the brain. The number of reported cases of anti-NMDAR encephalitis has increased rapidly. Anti-NMDAR encephalitis can be mistakenly diagnosed as psychiatric disorders because many patients present with prominent psychiatric symptoms and visit psychiatric institutions first. Thus, psychiatrists should cultivate a better understanding of anti-NMDAR encephalitis. In this review, we present the mechanisms, epidemiology, symptoms and clinical course, diagnostic tests, treatment and outcomes of patients with anti-NMDAR encephalitis. Furthermore, we discuss the diversity of clinical spectra of anti-NMDAR encephalitis, and demonstrate a differential diagnosis of psychiatric disease from the perspective of psychiatry.
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http://dx.doi.org/10.18926/AMO/56860DOI Listing
June 2019

Specific interactions of rotavirus HAL1166 with Enterobacter cloacae SENG-6 and their contribution on rotavirus HAL1166 removal.

Water Sci Technol 2019 Jan;79(2):342-348

Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan E-mail: Department of Frontier Science for Advanced Environment, Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi 980-8579, Japan.

Contribution of specific interactions between human enteric viruses and wastewater suspended solids on human enteric virus removal by microfiltration was studied. A cross-flow microfiltration system was used with rotavirus HAL1166 and Enterobacter cloacae SENG-6 as the model virus and wastewater suspended solid. Cleavage of rotavirus HAL1166 protein VP4 by trypsin produces the VP8* subunit, which specifically interacts with histo-blood group antigen (HBGA). In the presence of Enterobacter cloacae SENG-6, the trypsin-treated rotavirus concentration reduced with time (R > 0.6) compared to the reduction of non-trypsin treated rotavirus. Calculation of the gel/cake layer deposited on the membrane, consisting of Enterobacter cloacae SENG-6 and either trypsin-treated or non-trypsin treated rotavirus HAL1166, revealed that the microflocs consisting of trypsin-treated rotavirus and Enterobacter cloacae SENG-6 have lower porosity and permeability, displaying higher resistance to virus passage through the membrane. The results provide evidence that specific wastewater suspended solids-human enteric virus interaction can contribute to increasing the removal of human enteric viruses by microfiltration.
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http://dx.doi.org/10.2166/wst.2019.050DOI Listing
January 2019

IMACEL: A cloud-based bioimage analysis platform for morphological analysis and image classification.

PLoS One 2019 22;14(2):e0212619. Epub 2019 Feb 22.

Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan.

Automated quantitative image analysis is essential for all fields of life science research. Although several software programs and algorithms have been developed for bioimage processing, an advanced knowledge of image processing techniques and high-performance computing resources are required to use them. Hence, we developed a cloud-based image analysis platform called IMACEL, which comprises morphological analysis and machine learning-based image classification. The unique click-based user interface of IMACEL's morphological analysis platform enables researchers with limited resources to evaluate particles rapidly and quantitatively without prior knowledge of image processing. Because all the image processing and machine learning algorithms are performed on high-performance virtual machines, users can access the same analytical environment from anywhere. A validation study of the morphological analysis and image classification of IMACEL was performed. The results indicate that this platform is an accessible and potentially powerful tool for the quantitative evaluation of bioimages that will lower the barriers to life science research.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212619PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6386377PMC
November 2019

Effects of the antipsychotics haloperidol, clozapine, and aripiprazole on the dendritic spine.

Eur Neuropsychopharmacol 2018 05 21;28(5):610-619. Epub 2018 Mar 21.

Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.

Three types of antipsychotics, typical (e.g. haloperidol), atypical (e.g. clozapine), and dopamine partial agonist (e.g. aripiprazole), are administered for treatment of schizophrenia. These antipsychotics have different efficacy and side-effect profiles. We investigated whether aripiprazole, clozapine, and haloperidol differentially regulate the dendritic spine through the AKT-GSK-3 beta cascade. Dissociated cortical neurons from Sprague-Dawley rats were prepared and cultured for 28 days. Aripiprazole, clozapine, or haloperidol was administered to the rat cortical neurons. The levels of PSD95 protein and AKT-GSK-3 beta cascade-related proteins were investigated by Western blot. The number of spines and PSD95 puncta were investigated by immunofluorescence cell staining. Aripiprazole (1 µM or 10 µM) and clozapine (1 µM) increased the levels of PSD95 protein, the number of spines, phosphorylated Akt Thr308 and Ser473, and phosphorylated GSK-3 beta Ser9. On the other hand, haloperidol (1 µM or 10 µM) or an inappropriate concentration of clozapine (10 µM) decreased them. A GSK inhibitor also increased the levels of PSD-95 protein and caused the same morphology. Aripiprazole, clozapine, and haloperidol differentially regulate the dendritic spine, and this effect may occur through the AKT-GSK-3 beta cascade. Selection and appropriate dose of these antipsychotics may be important for the protection of dendritic spines in patients with schizophrenia.
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http://dx.doi.org/10.1016/j.euroneuro.2018.03.004DOI Listing
May 2018

Stemness and anti-cancer drug resistance in ATP-binding cassette subfamily G member 2 highly expressed pancreatic cancer is induced in 3D culture conditions.

Cancer Sci 2018 Apr 25;109(4):1135-1146. Epub 2018 Mar 25.

Research Team for Geriatric Medicine (Vascular Medicine), Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.

The expression of ATP-binding cassette subfamily G member 2 (ABCG2) is related to tumorigenic cancer stem cells (CSC) in several cancers. However, the effects of ABCG2 on CSC-related malignant characteristics in pancreatic ductal adenocarcinoma (PDAC) are not well elucidated. In this study, we compared the characteristics of low (ABCG2-) and high (ABCG2+)-ABCG2-expressing PDAC cells after cell sorting. In adherent culture condition, human PDAC cells, PANC-1, contained approximately 10% ABCG2+ cell populations, and ABCG2+ cells displayed more and longer microvilli compared with ABCG2- cells. Unexpectedly, ABCG2+ cells did not show significant drug resistance against fluorouracil, gemcitabine and vincristine, and ABCG2- cells exhibited higher sphere formation ability and stemness marker expression than those of ABCG2+ cells. Cell growth and motility was greater in ABCG2- cells compared with ABCG2+ cells. In contrast, epithelial-mesenchymal transition ability between ABCG2- and ABCG2+ cells was comparable. In 3D culture conditions, spheres derived from ABCG2- cells generated a large number of ABCG2+ cells, and the expression levels of stemness markers in these spheres were higher than spheres from ABCG2+ cells. Furthermore, spheres containing large populations of ABCG2+ cells exhibited high resistance against anti-cancer drugs presumably depending on ABCG2. ABCG2+ cells in PDAC in adherent culture are not correlated with stemness and malignant behaviors, but ABCG2+ cells derived from ABCG2- cells after sphere formation have stemness characteristics and anti-cancer drug resistance. These findings suggest that ABCG2- cells generate ABCG2+ cells and the malignant potential of ABCG2+ cells in PDAC varies depending on their environments.
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http://dx.doi.org/10.1111/cas.13533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5891171PMC
April 2018

Area-Specific Regulation of Quiescent Neural Stem Cells by Notch3 in the Adult Mouse Subependymal Zone.

J Neurosci 2017 12 3;37(49):11867-11880. Epub 2017 Nov 3.

Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan,

In the adult mammalian brain, neural stem cells (NSCs) generate new neurons throughout the mammal's lifetime. The balance between quiescence and active cell division among NSCs is crucial in producing appropriate numbers of neurons while maintaining the stem cell pool for a long period. The Notch signaling pathway plays a central role in both maintaining quiescent NSCs (qNSCs) and promoting cell division of active NSCs (aNSCs), although no one knows how this pathway regulates these apparently opposite functions. Notch1 has been shown to promote proliferation of aNSCs without affecting qNSCs in the adult mouse subependymal zone (SEZ). In this study, we found that Notch3 is expressed to a higher extent in qNSCs than in aNSCs while Notch1 is preferentially expressed in aNSCs and transit-amplifying progenitors in the adult mouse SEZ. Furthermore, Notch3 is selectively expressed in the lateral and ventral walls of the SEZ. Knockdown of Notch3 in the lateral wall of the adult SEZ increased the division of NSCs. Moreover, deletion of the gene resulted in significant reduction of qNSCs specifically in the lateral and ventral walls, compared with the medial and dorsal walls, of the lateral ventricles. Notch3 deletion also reduced the number of qNSCs activated after antimitotic cytosine β-D-arabinofuranoside (Ara-C) treatment. Importantly, Notch3 deletion preferentially reduced specific subtypes of newborn neurons in the olfactory bulb derived from the lateral walls of the SEZ. These results indicate that Notch isoforms differentially control the quiescent and proliferative steps of adult SEZ NSCs in a domain-specific manner. In the adult mammalian brain, the subependymal zone (SEZ) of the lateral ventricles is the largest neurogenic niche, where neural stem cells (NSCs) generate neurons. In this study, we found that Notch3 plays an important role in the maintenance of quiescent NSCs (qNSCs), while Notch1 has been reported to act as a regulator of actively cycling NSCs. Furthermore, we found that Notch3 is specifically expressed in qNSCs located in the lateral and ventral walls of the lateral ventricles and regulates neuronal production of NSCs in a region-specific manner. Our results indicate that Notch3, by maintaining the quiescence of a subpopulation of NSCs, confers a region-specific heterogeneity among NSCs in the adult SEZ.
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http://dx.doi.org/10.1523/JNEUROSCI.0001-17.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6596834PMC
December 2017

Crabs grab strongly depending on mechanical advantages of pinching and disarticulation of chela.

J Morphol 2016 10 11;277(10):1259-72. Epub 2016 Jul 11.

Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Furocho, Chikusa-Ku, Nagoya, 466-8601, Japan.

A small morphological variation of an organ may cause a major change of its function in animal evolution. The function of decapod chela varies considerably among taxa, between sex, and even within an individual, but also retains a simple mechanism of motion. Therefore, the decapod chela is a suitable structure to study the evolutionary process of functional diversifications, although the relationship of form and function is inadequately understood, yet. We estimated the mechanical advantages of pinching and passive disarticulation resistance, and chela size relative to the carapace in 317 chelae of 168 decapod specimens, and compared these indices with the functions of each chela. Our study revealed that mechanical advantages of pinching efficiency and passive disarticulation resistance were greatest in shell-crushing chelae, followed by gripping and pinching chelae, whereas the chela size relative to the carapace was not related to differences among these functions. We also found that the chelae are designed to retain the ratio between depth and width of the proximal dactylus. In the evolutionary process of decapods, the diversifications of chela functions were accompanied by the diversifications of the mechanical advantages, and played an essential role in their ecological diversification. J. Morphol. 277:1259-1272, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jmor.20573DOI Listing
October 2016

Randomized phase II study of second-line chemotherapy with the best available 5-fluorouracil regimen versus weekly administration of paclitaxel in far advanced gastric cancer with severe peritoneal metastases refractory to 5-fluorouracil-containing regimens (JCOG0407).

Gastric Cancer 2016 Jul 19;19(3):902-10. Epub 2015 Sep 19.

Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Japan.

Background: This randomized phase II study compared weekly administration of paclitaxel (wPTX) with the best available 5-fluorouracil (5-FU) regimen as second-line treatment for advanced gastric cancer patients with severe peritoneal metastasis refractory to fluoropyrimidine.

Methods: In the best available 5-FU arm, continuous infusion of 5-FU (800 mg/m(2)/day, days 1-5, every 4 weeks) was given to patients with prior chemotherapy including bolus 5-FU, and methotrexate and 5-FU sequential bolus injection (methotrexate at 100 mg/m(2) followed by bolus 5-FU at 600 mg/m(2) with leucovorin, weekly) was given to those who had previously received continuous infusion of 5-FU or oral administration of fluoropyrimidine. In the wPTX arm, paclitaxel (80 mg/m(2)) was administered on days 1, 8, and 15, every 4 weeks. This study adopted a screening design (one-sided α = 30 %) with the primary end point of overall survival.

Results: One hundred patients were randomized to the 5-FU arm (n = 49) or the wPTX arm (n = 51). Although the median survival time was 7.7 months in both arms, the 2-year survival rates were 2.9 % in the 5-FU arm and 9.1 % in the wPTX arm [hazard ratio 0.89 (95 % confidence interval 0.57-1.38), one-sided p = 0.298}. The median progression-free survival was longer with wPTX than with 5-FU [3.7 months vs 2.4 months; hazard ratio 0.58 (95 % confidence interval 0.38-0.88), one-sided p = 0.005]. The incidences of grade 4 neutropenia, grade 3/4 febrile neutropenia, diarrhea, and treatment-related death were 6 %, 4 %, 10 %, and 2 %, respectively, in the 5-FU arm and 2 %, 0 %, 0 %, and 0 %, respectively, in the wPTX arm.

Conclusions: As second-line chemotherapy, wPTX appears feasible and promising. This regimen can be included in a test arm in future phase III trials for treatment of advanced gastric cancer with severe peritoneal metastasis.
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http://dx.doi.org/10.1007/s10120-015-0542-8DOI Listing
July 2016

No Dynamic Changes in Inflammation-related Microcirculatory Parameters in Developing Rats During Local Cortex Exposure to Microwaves.

In Vivo 2015 Sep-Oct;29(5):561-7

Japan EMF Information Center, Tokyo, Japan.

The biological effects of exposing the developing brain to radiofrequency electromagnetic fields (RF) are still unclear. Our experiments investigated whether three inflammation-related, microcirculatory parameters in juvenile and young adult rats were modified during local cortex exposure to RF under non-thermal conditions. The cortex tissue was locally exposed to 1457 MHz RF at an averaged specific absorption rate of 2.0 W/kg in the target area for 50 min and variations of pial venule parameter were measured directly in vivo. There was no significant difference in hemodynamics, plasma velocity or vessel diameter, between exposed and sham-exposed groups for either rat development stage. No increase related to RF exposure was found in leukocyte adhesion to endothelial cells in any microvessels observed. These findings suggest that RF is unlikely to initiate inflammatory responses, at least under these exposure conditions.
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June 2016

No Dynamic Changes in Blood-brain Barrier Permeability Occur in Developing Rats During Local Cortex Exposure to Microwaves.

In Vivo 2015 May-Jun;29(3):351-7

Japan EMF Information Center, Tokyo, Japan.

Little information is available about the effects of exposure to radiofrequency electromagnetic fields (RF) on cerebral microcirculation during rat developmental stages. We investigated whether the permeability of the blood-brain barrier (BBB) in juvenile and young adult rats was modified during local cortex exposure to RF under non-thermal conditions. The cortex tissue targeted was locally exposed to 1457 MHz RF at an average specific absorption rate of 2.0 W/kg in the target area for 50 min and permeability changes in the BBB of the pia mater were measured directly, using intravital fluorescence microscopy. There was no significant difference in extravasation of intravenously-injected dye between exposed and sham-exposed groups of either category of rats. No histological evidence of albumin leakage was found in any of the brains just after exposure, indicating that no traces of BBB disruption remained. These findings suggest that no dynamic changes occurred in BBB permeability of the rats at either of these developmental stages, even during local RF exposure at non-thermal levels.
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February 2016

Slowly dividing neural progenitors are an embryonic origin of adult neural stem cells.

Nat Neurosci 2015 May 30;18(5):657-65. Epub 2015 Mar 30.

Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.

The mechanism by which adult neural stem cells (NSCs) are established during development is unclear. In this study, analysis of cell cycle progression by examining retention of a histone 2B (H2B)-GFP fusion protein revealed that, in a subset of mouse embryonic neural progenitor cells (NPCs), the cell cycle slows between embryonic day (E) 13.5 and E15.5 while other embryonic NPCs continue to divide rapidly. By allowing H2B-GFP expressed at E9.5 to become diluted in dividing cells until the young adult stage, we determined that a majority of NSCs in the young adult subependymal zone (SEZ) originated from these slowly dividing embryonic NPCs. The cyclin-dependent kinase inhibitor p57 is highly expressed in this embryonic subpopulation, and the deletion of p57 impairs the emergence of adult NSCs. Our results suggest that a substantial fraction of adult SEZ NSCs is derived from a slowly dividing subpopulation of embryonic NPCs and identify p57 as a key factor in generating this embryonic origin of adult SEZ NSCs.
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http://dx.doi.org/10.1038/nn.3989DOI Listing
May 2015

The mechanism of slow hot-hole cooling in lead-iodide perovskite: first-principles calculation on carrier lifetime from electron-phonon interaction.

Nano Lett 2015 May 1;15(5):3103-8. Epub 2015 Apr 1.

†Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

We report on an analysis of hot-carrier lifetimes from electron-phonon interaction in lead iodide perovskites using first-principles calculations. Our calculations show that the holes in CsPbI3 have very long lifetimes in the valence band region situated 0.6 eV below the top of the valence band. On the other hand, no long lifetime is predicted in PbI3(-). These different results reflect the different electronic density of states (DOSs) in the valence bands, that is, a small DOS for the former structure while a sharp DOS peak for the latter structure. We propose a reduction of the relaxation paths in the small valence DOS as being the origin of the slow hot-hole cooling. Analyzing the generalized Eliashberg functions, we predict that different perovskite A-site cations do not have an impact on the carrier decay mechanism. The similarity between the DOS structures of CsPbI3 and CH3NH3PbI3 enables us to extend the description of the decay mechanism of fully inorganic CsPbI3 to its organic-inorganic counterpart, CH3NH3PbI3.
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http://dx.doi.org/10.1021/acs.nanolett.5b00109DOI Listing
May 2015

Multigenerational effects of whole body exposure to 2.14 GHz W-CDMA cellular phone signals on brain function in rats.

Bioelectromagnetics 2014 Oct 4;35(7):497-511. Epub 2014 Sep 4.

Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.

The present experimental study was carried out with rats to evaluate the effects of whole body exposure to 2.14 GHz band code division multiple access (W-CDMA) signals for 20 h a day, over three generations. The average specific absorption rate (SAR, in unit of W/kg) for dams was designed at three levels: high (<0.24 W/kg), low (<0.08 W/kg), and 0 (sham exposure). Pregnant mothers (4 rats/group) were exposed from gestational day (GD) 7 to weaning and then their offspring (F1 generation, 4 males and 4 females/dam, respectively) were continuously exposed until 6 weeks of age. The F1 females were mated with F1 males at 11 weeks old, and then starting from GD 7, they were exposed continuously to the electromagnetic field (EMF; one half of the F1 offspring was used for mating, that is, two of each sex per dam and 8 males and 8 females/group, except for all offspring for the functional development tests). This protocol was repeated in the same manner on pregnant F2 females and F3 pups; the latter were killed at 10 weeks of age. No abnormalities were observed in the mother rats (F0 , F1 , and F2 ) and in the offspring (F1 , F2 , and F3 ) in any biological parameters, including neurobehavioral function. Thus, it was concluded that under the experimental conditions applied, multigenerational whole body exposure to 2.14 GHz W-CDMA signals for 20 h/day did not cause any adverse effects on the F1 , F2 , and F3 offspring.
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http://dx.doi.org/10.1002/bem.21871DOI Listing
October 2014

Multi-wall effects on the thermal transport properties of nanotube structures.

Nanotechnology 2014 Jun 28;25(24):245703. Epub 2014 May 28.

Department of Chemical System Engineering, Graduate School of Engineering, the University of Tokyo, Tokyo 113-8656, Japan.

Understanding the role of inter-layer interactions in multi-walled carbon nanotubes is one of the challenges in the design of potential materials because of their large impact on the physical properties of carbon nanotubes. We focused on the thermal properties of double-walled carbon nanotubes (DWCNTs), which are promising materials due to their high durability and thermal efficiency. We investigated the thermal conductance of DWCNTs by using the nonequilibrium Green's function method, and found that the quadratic temperature dependence of the thermal conductance at low temperatures consisted of three regions with different tendencies. Based on analysis of the transmission coefficients and the distribution of the normal modes, the three nonuniform regions were attributed to the energy shifts of the normal modes at the low-energy region. We examined the mechanism of these energy shifts using the coupled vibration model with the parameters from our simulations, and elucidated the multi-wall effects on the thermal transport properties of the nanotube structures. The effects we found demonstrated the significance of tailoring thermal properties to obtain the desired applications.
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http://dx.doi.org/10.1088/0957-4484/25/24/245703DOI Listing
June 2014

[Multicenter surveillance of Pseudomonas aeruginosa strains for antimicrobials in Aichi prefecture in 2009].

Jpn J Antibiot 2013 Aug;66(4):211-25

We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance, the results should be reported by stratifying with patient status, and type of specimens that the strain was isolated from and that regional surveillance should be useful with such stratification to establish antibiograms for empirical antimicrobial choice.
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August 2013

Chirality dependence of quantum thermal transport in carbon nanotubes at low temperatures: a first-principles study.

J Chem Phys 2013 Jul;139(4):044711

Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.

We study the transport properties of single-walled carbon nanotubes (SWCNTs) using the nonequilibrium Green's function method based on first-principles calculations. We compared three SWCNTs with different chiralities (3, 3), (5, 0), and (4, 2), and found that the thermal conductance varies significantly with the chirality, especially at low temperatures. Such differences are attributed to the dependence on the chirality of the frequency of the lowest optical mode and phonon-phonon interaction with the semi-infinite leads. To obtain accurate low-vibrational frequencies, a force constant correction based on the Lagrange undetermined multiplier method was employed. The phonon-phonon interaction was analyzed in terms of the projection of the phonon coupling with the semi-infinite leads onto the normal modes of the center region. Our result indicates that high optical mode frequency and weak phonon coupling on the armchair (3, 3) SWCNT are the origin of the long quantized plateau found in the experimental thermal conductance.
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http://dx.doi.org/10.1063/1.4816476DOI Listing
July 2013

Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

Nat Commun 2013 ;4:1880

Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.

Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.
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http://dx.doi.org/10.1038/ncomms2895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675328PMC
December 2013

Coexpression of organic anion-transporting polypeptides 1B3 and multidrug-resistant proteins 2 increases the enhancement effect of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid on hepatocellular carcinoma in magnetic resonance imaging.

Hepatol Res 2014 Mar 7;44(3):327-37. Epub 2013 May 7.

Department of Gastroenterology, Nagoya City West Medical Center, Nagoya, Japan.

Aim: We aimed to elucidate the relationship between the contrast enhancement effect of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) on magnetic resonance imaging (MRI) of hepatocellular carcinomas (HCC) and the expressions of hepatocyte transporters (i.e. organic anion-transporting polypeptide [OATP]1B3, multidrug-resistant protein [MRP]2 and MRP3) and to clarify the characteristics of HCC with an MRI high-contrast enhancement effect.

Methods: We retrospectively examined the relationship between the relative enhancement ratio (RER) of HCC, absolute and relative immunohistochemical staining scores of hepatocyte transporters, and histological differentiation of 22 HCC from 21 patients who had undergone preoperative Gd-EOB-DTPA-enhanced MRI.

Results: RER had a significant correlation with OATP1B3 expression according to the absolute and relative scores (P = 0.016 vs 0.0006). The RER of HCC with high OATP1B3 and MRP2 expression levels was higher than that of HCC with low OATP1B3 or MRP2 expression levels (P = 0.0003). The RER of HCC with higher OATP1B3 rates was greater than that of HCC with lower OATP1B3 rates (P = 0.0005). HCC histological differentiation showed a significant correlation with OATP1B3 expression and RER (P = 0.023 vs 0.0095).

Conclusion: We found that coexpression of OATP1B3 and MRP2 influenced the high contrast enhancement of HCC on MRI.
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http://dx.doi.org/10.1111/hepr.12128DOI Listing
March 2014

Efficacy of docetaxel in patients with paclitaxel-resistant advanced gastric cancer.

Gan To Kagaku Ryoho 2012 Oct;39(10):1511-5

Dept.of Clinical Oncology, Aichi Cancer Center Hospital, Aichi, Japan.

Background: Although there appears to be incomplete cross-resistance between docetaxel and paclitaxel in several types of malignancies, to our best knowledge there have been no available data on this for advanced gastric cancer.

Methods: We retrospectively evaluated the efficacy and safety of docetaxel in patients with paclitaxel-resistant advanced gastric cancer. Docetaxel was administered at 50-60 mg/m2 every 3 weeks.

Results: Twenty-one patients were evaluated. All patients had received 2 or more previous chemotherapy regimens. Among the 12 patients with measurable lesions, apparent tumor shrinkage was seen in 1 patient for an overall response rate of 8. 3% and a disease control rate of 33. 3%. Median progression free survival and overall survival of all patients were 2. 6 months and 6. 7 months, respectively. There were no correlations between the progression free survival of docetaxel and the progression free survival of previous paclitaxel and between the progression free survival of docetaxel and taxane-free interval(Spearman's correlation coefficients of ρ=-0. 14 and ρ=-0. 02, respectively). Grade 3/4 neutropenia developed in 8 patients(38%)and Grade 3 febrile neutropenia in 1 patient(4. 8%).

Conclusions: Docetaxel showed modest activity in paclitaxel-resistant advanced gastric cancer patients, and no correlations between previous efficacy of paclitaxel or taxane-free interval were seen.
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October 2012

Efficacy of mosapride citrate with polyethylene glycol solution for colonoscopy preparation.

World J Gastroenterol 2012 May;18(20):2517-25

Department of Endoscopy, Aichi Cancer Center Hospital, Nagoya 464-8681, Japan.

Aim: To evaluate the efficacy and safety of adjunctive mosapride citrate for bowel preparation before colonoscopy.

Methods: We conducted a randomized, double-blind, placebo-controlled study with mosapride in addition to polyethylene glycol (PEG)-electrolyte solution. Of 250 patients undergoing colonoscopy, 124 were randomized to receive 2 L PEG plus 15 mg of mosapride citrate (mosapride group), and 126 received 2 L PEG plus placebo (placebo group). Patients completed a questionnaire reporting the acceptability and tolerability of the bowel preparation process. The efficacy of bowel preparation was assessed by colonoscopists using a 5-point scale based on Aronchick's criteria. The primary end point was optimal bowel preparation rates (scores of excellent/good/fair vs poor/inadequate).

Results: A total of 249 patients were included in the analysis. In the mosapride group, optimal bowel preparation rates were significantly higher in the left colon compared with the placebo group (78.2% vs 65.6%, P < 0.05), but not in the right colon (76.5% vs 66.4%, P = 0.08). After excluding patients with severe constipation, there was a significant difference in bowel preparation in both the left and right colon (82.4% vs 66.7%, 80.8% vs 67.5%, P < 0.05, P < 0.01). The incidence of adverse events was similar in both groups. Among the subgroup who had previous colonoscopy experience, a significantly higher number of patients in the mosapride group felt that the current preparation was easier compared with patients in the placebo group (34/72 patients vs 24/74 patients, P < 0.05).

Conclusion: Mosapride citrate may be an effective and safe adjunct to PEG-electrolyte solution that leads to improved quality of bowel preparation, especially in patients without severe constipation.
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http://dx.doi.org/10.3748/wjg.v18.i20.2517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3360450PMC
May 2012

Multicenter retrospective study of 132 patients with unresectable small bowel adenocarcinoma treated with chemotherapy.

Oncologist 2012 23;17(9):1163-70. Epub 2012 May 23.

Division of Gastrointestinal Oncology, Shizuoka Cancer Center, 1007 Shimonagakubo Nagaizumi-cho Sunto-gun, Shizuoka, Japan.

Background: No standard chemotherapy regimen has been established for unresectable or recurrent small bowel adenocarcinoma (SBA).

Methods: Clinical courses of 132 patients with unresectable or recurrent SBA who received chemotherapy at 41 institutions in Japan were reviewed retrospectively. Patients were classified into five groups according to first-line chemotherapy regimens: fluoropyrimidine monotherapy (group A), fluoropyrimidine-cisplatin (group B), fluoropyrimidine-oxaliplatin (group C), fluoropyrimidine-irinotecan (group D), and other regimens (group E).

Results: The number of patients in each group was as follows: groups A, 60 patients; group B, 17 patients; group C, 22 patients; group D, 11 patients; and group E, 22 patients. Median progression-free survival (PFS) times were as follows: group A, 5.4 months; group B, 3.8 months; group C, 8.2 months; group D, 5.6 months; and group E, 3.4 months. Median overall survival (OS) times were as follows: group A, 13.9 months; group B, 12.6 months; group C, 22.2 months; group D, 9.4 months; and group D, 8.1 months. Patients in group C achieved significantly longer PFS times and substantially (but not significantly) longer OS times than patients in group A. After adjusting for clinical background characteristics, fluoropyrimidine-oxaliplatin therapy was a significant positive prognostic factor for PFS and OS times.

Conclusion: The results suggest that fluoropyrimidine-oxaliplatin combination therapy is the most promising first-line chemotherapy regimen for unresectable or recurrent SBA.
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http://dx.doi.org/10.1634/theoncologist.2012-0079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3448409PMC
February 2013

Statistical determination of whole-body average SARs in a 2 GHz whole-body exposure system for unrestrained pregnant and newborn rats.

Phys Med Biol 2012 Jan 30;57(1):143-54. Epub 2011 Nov 30.

Department of Computer Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.

A 2 GHz whole-body exposure to rats over a multigeneration has been conducted as part of bio-effect research in Japan. In this study, the rats moved freely in the cage inside the exposure system. From observation of the activity of rats in the cage, we found that the rats do not stay in each position with uniform possibility. In order to determine the specific absorption rate (SAR) during the entire exposure period with high accuracy, we present a new approach to statistically determine the SAR level in an exposure system. First, we divided the rat cage in the exposure system into several small areas, and derived the fraction of time the rats spent in each small area based on the classification of the documentary photos of rat activity. Then, using the fraction of time spent in each small area as a weighting factor, we calculated the statistical characteristics of the whole-body average SAR for pregnant rats and young rats during the entire exposure period. As a result, this approach gave the statistical distribution as well as the corresponding mean value, median value and mode value for the whole-body SAR so that we can reasonably clarify the relationship between the exposure level and possible biological effect.
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http://dx.doi.org/10.1088/0031-9155/57/1/143DOI Listing
January 2012
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