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T Hiraoka

Publications and source records attributed to T Hiraoka.

At least 19 recordsLinked to original sources
PubMed2006

Investigation of new cytogenetic biomarkers specific to high-LET radiation using in vivo and in vitro exposed human lymphocytes.

PURPOSE: To find detectable cytogenetic biomarkers that can offer information about the radiation quality of in vivo exposure retrospectively. MATERIALS AND METHODS: Chromosome-type aberrations of peripheral lymphocytes of uterine cancer patients that received internal gamma- and external X-ray therapy or carbon beam therapy and of victims severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan were analysed. Data obtained from in vitro irradiation experiments using 60Co gamma-rays and 10 MeV neutrons were compared with the in vivo exposure data. RESULTS: The ratio of acentric rings to dicentric chromosomes (termed RaD ratio) and that of excess fragments to dicentrics (termed EfD ratio) showed significant (p < 0.05) differences between the two groups of cancer patients, and these ratios for accidental victims were in between the values of the two groups of cancer patients. The in vitro studies using doses equivalent to 1 - 3 Gy of gamma-rays have confirmed that the EfD ratios were increased with the high LET (linear energy transfer) and RaD ratios decreased. CONCLUSION: The present data show that the RaD and EfD ratios can be used as cytogenetic biomarkers of exposure to high-LET radiation at least within a few years of exposure.

Aged↗
PubMed2006

Retention and removal of a new viscous dispersive ophthalmic viscosurgical device during cataract surgery in animal eyes.

AIMS: To assess the retention and removal properties of a new viscous dispersive ophthalmic viscosurgical device (OVD), DisCoVisc, in comparison with those of cohesive (Provisc), dispersive (Viscoat), and viscoadaptive (Healon5) OVDs. METHODS: In 20 porcine eyes, cataract surgery was simulated using one of the four OVDs which were stained with fluorescein for better visualisation. Three parameters were measured. Firstly, the presence/absence of OVDs in the chamber at the completion of phacoemulsification was recorded. Secondly, the time until the OVDs were completely removed from the anterior chamber using the phaco needle was measured. Thirdly, after intraocular lens (IOL) implantation, the time needed to completely remove the OVDs from the chamber with irrigation/aspiration tip was recorded. RESULTS: At the completion of phacoemulsification, the OVDs retained in 0% (0/5) for Provisc, 80% (4/5) for Healon5, 100% (5/5) for DisCoVisc, and 100% (5/5) for Viscoat. The retention of OVDs during phacoemulsification was greatest with Viscoat followed by, in descending order, DisCoVisc, Healon5, and Provisc. The removal of OVDs after IOL implantation took longest with Viscoat followed by Healon5, DisCoVisc, and Provisc. CONCLUSION: The viscous dispersive DisCoVisc showed excellent retention during phacoemulsification, while its removal after IOL implantation was very easy. When compared with the viscoadaptive Healon5, DisCoVisc was retained better in the chamber and was easier to remove. These features of DisCoVisc should be highly advantageous when considering covering the entire cataract surgery procedure with a single OVD.

Animals↗
PubMed2005

A new method using F-waves to measure muscle fiber conduction velocity (MFCV).

OBJECTIVE: First, to propose a new technique for measuring muscle fiber conduction velocity (MFCV). Second, to ascertain the validation of the new method that uses F-waves (F-MFCV) in healthy volunteers. Third, to examine the relationship between F-MFCV and motor nerve conduction velocity (MCV) in the same subjects. SUBJECTS AND METHODS: F-waves reflecting single motor units were recorded with a multi-channel surface electrode array and weak electrical stimulation to the median or ulnar nerves in 21 healthy volunteers. F-MFCVs of the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) were calculated from the F-wave peak latency in each channel. MFCV during minimal voluntary contraction (V-MFVC) was measured in the same muscles. RESULTS: There was no significant difference between F-MFCV and V-MFCV in the muscles tested The mean F-MFCV value was similar to recently reported MFCV values generated by minimal voluntary contraction. No significant differences were found between the APB and ADM F-MFCVs, whereas the MCV of the ulnar nerve was faster than that of the median nerve. CONCLUSION: The MFCV in a single motor unit could be measured with a multi-channel surface electrode array by recording F-waves induced by weak stimulation. Since V-MFCV generated by minimal voluntary contraction is explained by the size principle, V-MFCV reflects small and slow conducting motor unit. There was no significant difference between F-MFCV and V-MFCV. It seemed that F-MFCV also reflected small motor unit. The reason for the lack of difference in the F-MFCVs of the ADM and APB is considered to be a relatively slow F-MFCV. Moreover, MCV reflected the speed of the fastest nerve fiber, whereas F-MFCV did not.

Action Potentials↗
PubMed2002

[Report on the 13th European Congress of Radiology (ECR): Comparison of primary proton beams and secondary charged-particles].

PURPOSE: In the proton radiotherapy, primary proton beams contribute to the absorbed dose and the share of secondary charged-particles is small. The purpose is to discuss about the ratio of average dose of primary proton beams and secondary charged-particles. METHODS: We performed the dosimetry of 70 MeV proton beams in water using ionization chamber. The ratio of average dose for secondary charged-particles in some range shifter was calculated by the dose ratio of primary and scatter. To exclude the influence of lateral secondary charged-particles, the ratio of average dose for secondary charged-particles was extrapolated to zero field size of each. RESULTS: The ratio of average dose for secondary charged-particles was extrapolated to zero field size by the bi-exponential fit. The ratio of average dose for longitudinal secondary charged-particles for zero fields at each depth is almost the same; the different at the shallow depth is decreased. CONCLUSIONS: The secondary charged-particles from collimator is affected by the dose of shallow depth. The influence of lateral secondary charged-particles in water phantom was excluded with the extrapolation method for zero field size in each depth.

Alpha Particles↗
PubMed2001

Transient interhemispheric neuronal synchrony correlates with object recognition.

Object recognition might be achieved by the recreation of a meaningful internal image from visual fragments. This recreation might be achieved by neuronal synchronization that has been proposed as a solution for the perceptual binding problem. In this study, we evaluated synchronization between the occipitotemporal regions bilaterally using electroencephalograms during several visual recognition tasks. Conscious recognition of familiar objects spanning the visual midline induced transient interhemispheric electroencephalographic coherence in the alpha band, which did not occur with meaningless objects or with passive viewing. Moreover, there was no interhemispheric coherence when midline objects were not recognized as meaningful or when familiar objects were presented in one visual hemifield. These data suggest a close link between site-specific interregional synchronization and object recognition.

Adult↗
PubMed2001

Loss of alveolar basement membrane type IV collagen alpha3, alpha4, and alpha5 chains in bronchioloalveolar carcinoma of the lung.

Type IV collagen, the major component of basement membrane (BM), is composed of six genetically distinct alpha(IV) chains. This study investigated for the first time the expression of these six alpha(IV) chains immunohistochemically, using alpha(IV) chain-specific monoclonal antibodies, in normal lung and in small (less than 2 cm in diameter) adenocarcinoma of the lung with a bronchioloalveolar growth pattern at the periphery. Small adenocarcinomas were histopathologically classified into three subtypes: bronchioloalveolar carcinoma (BAC) without collapse, BAC with collapse, and adenocarcinoma with bronchioloalveolar features. In normal lung, alveolar BM was composed of alpha1(IV)/alpha2(IV) chains and alpha3(IV)/alpha4(IV)/alpha5(IV) chains. In non-collapsed areas of BAC, alveolar BM was composed of linear alpha1(IV)/alpha2(IV) chains and discontinuous alpha3(IV)/alpha4(IV)/alpha5(IV) chains. In collapsed areas of BAC, alveolar BM was composed of linear and thick alpha1(IV)/alpha2(IV) chains only, because of the complete loss of alpha3(IV)/alpha4(IV)/alpha5(IV) chains. In invasive areas of adenocarcinoma with bronchioloalveolar features, alpha1(IV)/alpha2(IV) chains around the cancer cell nests were disrupted, in addition to the complete loss of alpha3(IV)/alpha4(IV)/alpha5(IV) chains. In conclusion, during the process of stromal invasion of lung adenocarcinoma, type IV collagen of alveolar BM is remodelled from the complete type, composed of alpha1(IV)/alpha2(IV)/alpha3(IV)/alpha4(IV)/alpha5(IV) chains, to the incomplete type, composed of only alpha1(IV)/alpha2(IV) chains, before the disruption of alpha1(IV)/alpha2(IV) chains. These findings may help to clarify the molecular mechanisms of cancer invasion.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2001

Lymphatic spreading pattern of intrahepatic cholangiocarcinoma.

BACKGROUND: There have been very few reports on the pattern of lymphatic spread of intrahepatic cholangiocarcinoma. This pattern was elucidated to help define the rational extent of radical lymph node dissection. METHODS: Thirty-nine consecutive patients who underwent hepatectomy with radical lymph node dissection were reviewed retrospectively. RESULTS: Lymph node metastases were detected in 24 of the 39 patients (62%). The metastatic nodes were found in the hepatoduodenal ligament, along the common hepatic artery, around the abdominal aorta, on the posterior surface of the pancreas head, along the left gastric artery, along the superior mesenteric artery, around the celiac artery, along the lesser curvature of the stomach, and around the cardia. The nodal involvements along the left gastric artery, along the lesser curvature, or around the cardia were recognized only in the left peripheral and hilar types of cholangiocarcinoma, while all other sites included both the left or right peripheral type and the hilar type cholangiocarcinoma. CONCLUSIONS: Intrahepatic cholangiocarcinomas, irrespective of their intrahepatic location, mainly spread to the nodes in the hepatoduodenal ligament, then to the para-aortic nodes, retropancreatic nodes, or common hepatic artery nodes. In addition to these spreading routes, the left peripheral type or hilar type of cholangiocarcinoma tends to spread along the left gastric nodes through the lesser curvature.

Adult↗
PubMed2001

Apoptotic cells of an epithelial cell line, AsPC-1, release monocyte chemotactic S19 ribosomal protein dimer.

A pancreatic carcinoma cell line, AsPC-1, underwent apoptosis in vitro when heat-treated for 60 min at 43 degrees C. Apoptotic AsPC-1 cells liberated a monocyte chemotactic factor into the culture supernatant 24 to 30 h after the heat-treatment. This factor was immunologically identified as the cross-linked homodimer of S19 ribosomal protein (RP S19), since the majority of the chemotactic activity was absorbed by both anti--RP S19 rabbit antibodies and an anti--isopeptide bond monoclonal antibody immobilized on agarose beads. Intracellular transglutaminase activity increased during the apoptotic process, reaching the peak strength between 18 and 24 h after the heat-treatment. A recombinant RP S19 acquired the monocyte chemotactic capacity when incubated with the apoptotic cell extract obtained at the 18th hour. The chemotactic activity acquirement as well as the transglutaminase activity were blocked by treatment of the extract with anti--type II transglutaminase rabbit antibodies. When the recombinant RP S19 was treated with an authentic type II transglutaminase, the dimerization of RP S19 concomitant with the generation of the monocyte chemotactic activity was observed. Peptide-map analyses involving amino acid sequencing demonstrated that the inter-molecular isopeptide bond was heterogeneous: Gln12 or Gln137 and Lys29 or Lys122 were cross-linked. Site-directed mutagenic analysis indicated that the cross-linking of Gln137, but not other residues such as Gln12, Lys29, and Lys122, was essential for expression of the chemotactic activity.

Amino Acid Sequence↗
PubMed2001

An operated case of lung cancer with pleural plaques: its asbestos bodies, fiber analysis and asbestos exposure.

This case was a 79-year-old man with pleural plaques, which had been pointed out in the left lung field on chest X-ray six years ago. A new shadow in the right chest appeared in 1999 and was closely examined. Cytological class IV carcinoma was detected in his lung tissue obtained by broncho-fiberscope. Lobectomy of the right upper lobe was performed, and calcified pleural plaques were found on the chest wall. The clinical diagnosis was poorly differentiated squamous cell carcinoma, T1N0M0. In World War II when he was 26 years old, he had worked as a boiler man on a battle cruiser for one year. The amount of asbestos bodies (AB) was 3,348 per gram dry lung tissue. The cores of AB and asbestos fibers were examined and showed that amosite was the most prevalent and crocidolite, tremolite and chrysotile were present in that order. After leaving the navy, he had worked as a farmer throughout his life, suggesting that he had never contacted asbestos occupationally after being a boiler man. It is strongly suggested that he had been exposed to asbestos during his work as a boiler man and that produced pleural plaques and lung cancer 50 years' later.

Aged↗
PubMed2001

[The alternative or simultaneous excretion of different species of mycobacteria in atypical mycobacteriosis--15 cases in 7 years].

Five hundreds and five cases of Mycobacterium tuberculosis infection admitted to our hospital during 7 years from 1993 to 1999. Numbers of newly diagnosed cases were 390, of which 329 (84.4%) were bacilli positive with sputum examination on admission. The recurrent cases were 115, of which 55 (47.8%) were bacilli positive cases. During the same period, mycobacteria other than tuberculosis (atypical mycobacteria) were detected in the sputum of other 121 cases. The 63 (52.1%) out of these 121 cases were diagnosed as atypical mycobacteriosis (AM) due to repetitive detection of bacilli with fulfilled the criteria according to the Japanese Mycobacteriosis Research Group of the National Chest Hospitals. The ratio of 63 AM cases to 329 bacilli positive TB cases was 19.1%, but it range from 8.2% to 31.3% year by year. In these 63 AM cases, 9 (14.3%) cases excreted AM bacilli simultaneously or alternately with TB bacilli. The other 15 (23.8%) cases excreted different AM bacilli simultaneously or alternately. The changes or combinations with M. avium and M. intracellulare were most frequently observed (in 12 cases). The manners of changes and combinations with different species were described in detail.

Humans↗
PubMed2000

NE-dlg, a mammalian homolog of Drosophila dlg tumor suppressor, induces growth suppression and impairment of cell adhesion: possible involvement of down-regulation of beta-catenin by NE-dlg expression.

Membrane-associated guanylate kinases (MAGUKs) are known to function as scaffolds for forming multiprotein complexes at the synaptic junctions of neuronal cells and at sites of epithelial cell-cell contact. In Drosophila, mutations of the lethal (1)-discs large (dlg) gene, which encodes a MAGUK protein, leads to post-synaptic structure defects in neuronal cells and neoplastic overgrowth of epithelial cells. We previously showed that NE-dlg (neuronal and endocrine dlg), a human homolog of the dlg, plays a crucial role in formation of synaptic structure in human neuronal cells. Here we demonstrate that NE-dlg, similar to Drosophila dlg, is involved in regulation of cell cycle progression and adhesive ability of non-neuronal cells. Overexpression of NE-dlg in proliferating cells including various cancer cell lines induced growth suppression and impairment of cell adhesive ability. Furthermore, NE-dlg overexpression caused the down-regulation of beta-catenin in cancer cells regardless of mutations in the APC (adenomatous polyposis coli) gene. The PDZ domains of NE-dlg were found to be essential for the growth suppression, loss of adhesive property and down-regulation of beta-catenin. We propose that NE-dlg regulates the cell growth and adhesive ability by controlling the level of beta-catenin through an APC-independent pathway. Inactivation of NE-dlg may therefore contribute to development and/or progression of human neoplasms.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Incorporation of artificial receptors into a protein/peptide surface: a strategy for on/off type of switching of semisynthetic enzymes.

Recent developments in new bioorganic methodologies have greatly facilitated the site-specific incorporation of non-natural amino acids into the protein framework. It is now desirable for chemists to explore promising concepts based on chemistry for regulation and extension of functions of naturally occurring enzymes using non-natural molecules, in order to promote the new trends in protein/enzyme engineering. This article demonstrates that the concepts of host-guest (or supramolecular) chemistry, which have been developed over the last few decades, provide powerful tools for the artificial control of the functions of native proteins and enzymes.

Amino Acid Sequence↗
PubMed2000

Growth-promoting effects of ecdysteroids and juvenile hormone on in vitro development of the larval endoparasitoid, Venturia canescens (Hymenoptera: Ichneumonidae).

We previously reported that lipophorin, fetal bovine serum (FBS), and 20-hydroxyecdysone (20-HE) are essential for the development of the larval endoparasitoid Venturia canescens larvae in vitro. The present study was undertaken to determine the optimal concentrations of those three substances in the MGM-450 medium, and to examine the hormonal effects of ecdysteroids and juvenile hormone (JH) on the development of the parasitoid larvae in vitro. When the culture was started with embryos at the post-germband stage, concentrations of 3 mg/ml of lipophorin and 20% of FBS were most suitable for the development of the parasitoid. The growth-promoting effect of 20-HE increased in a concentration-dependent manner and peaked at a concentration of 1 &mgr;g/ml. Excess concentration led to malformations of the larvae. Three other ecdysteroids, ecdysone, 2-deoxy-20-hydroxyecdysone, and polypodine B had the same effect, although their activity was lower than that of 20-HE. Cholesterol had no effect; most larvae failed to develop. When the medium was supplemented with JH, the duration of the developmental period was significantly shortened, but this hormone was not found to be essential.

Journal Article↗
PubMed2000

Lipophorin as a yolk protein precursor in the mosquito, Aedes aegypti.

We examined expression of the lipophorin (Lp) gene, lipophorin (Lp) synthesis and secretion in the mosquito fat body, as well as dynamic changes in levels of this lipoprotein in the hemolymph and ovaries, during the first vitellogenic cycle of females of the yellow fever mosquito, Aedes aegypti. Lipophorin was purified by potassium bromide (KBr) density gradient ultracentrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Polyclonal antibodies were produced against individual Lp apoproteins, apolipoprotein-I (apoLp-I) and apolipoprotein-II (apoLp-II), with molecular weights of 240 and 75 kDa, respectively. We report here that in the mosquito A. aegypti, Lp was synthesized by the fat body, with a low level of the Lp gene expression and protein synthesis being maintained in pre- and postvitellogenic females. Following a blood meal, the Lp gene expression and protein synthesis were significantly upregulated. Our findings showed that the fat body levels of Lp mRNA and the rate of Lp secretion by this tissue reached their maximum at 18 h post-blood meal (PMB). 20-Hydroxyecdysone was responsible for an increase in the Lp gene expression and Lp protein synthesis in the mosquito fat body. Finally, the immunocytochemical localization of Lp showed that in vitellogenic female mosquitoes, this protein was accumulated by developing oocytes where it was deposited in yolk granules.

Aedes↗
PubMed2000

Intraductal papillary tumors of the pancreas. Histopathologic correlation of MR cholangiopancreatography findings.

PURPOSE: To evaluate MR cholangiopancreatography (MRCP) findings of intraductal papillary tumors of the pancreas and correlate them with histopathology. MATERIAL AND METHODS: Seventeen patients with intraductal papillary tumor of the pancreas underwent MRCP before surgery. MRCP findings were correlated to histopathology with regard to the presence of septa and excrescent nodules in the cystic lesion, communication between the cystic lesion and the main pancreatic duct (MPD), degree of dilatation of MPD, and dilatation of the common bile duct (CBD). RESULTS: MRCP demonstrated septa in 17 cases (100%), excrescent nodules in 8 cases (47.1%), communication between the intraductal papillary tumor and the MPD in 14 cases (82.3%), dilatation of MPD over 50% in 6 cases (35.3%), and dilatation of CBD in 3 cases (17.6%). These findings showed excellent correlation with histopathology. The septum on MRCP corresponded with a layer of connective tissue with pancreatic duct epithelium. Excrescent nodules in the carcinomas consisted not only of malignant cells, but also of dysplasia and adenoma. Excrescent nodules in adenomas were consistent not only with minimal papillary growth of adenoma, but also with proliferation of fibrosis, and hematoma and organized fibrin with minimal fibrosis. Pancreatic tissue was affected by chronic pancreatitis in all cases. Cases with dilatation of CBD on MRCP were due to microscopic invasion by the carcinoma. CONCLUSION: MRCP appearances of intraductal papillary tumors are well correlated with the findings at histopathology.

Adenocarcinoma, Papillary↗
PubMed2000

Aspects of fast-ion dosimetry.

A first step in the dosimetry of fast-ion beams is the determination of accurate Bragg (ionization) functions. Bragg functions for several substances have been measured and calculated for 3480 MeV carbon ions. In the measurements, the ions first traverse an absorber in which the energy is reduced to either 1900 or 1200 MeV, then a "range gauge" followed by a thin ionization chamber. Functions are calculated with an analytical method using convolutions of straggling functions. This approach gives results without the stochastic variations implicit in Monte Carlo methods. The comparison of measured and calculated functions shows how reliable the calculations are. An important part of the calculations is the determination of the total range of the ions. The range can be determined from the Bragg function. The measured range is given by the sum of the thickness of the absorber and the residual range measured with the range gauge. For water, the range is about 150 mm, and the precision of the measurements is +/-0.05 mm. Because the ion energy at the surface of the absorber fluctuates with time, measurements with water are used to define this energy. Thus the ranges (or average stopping powers) in absorbers are obtained relative to those in water. Measured ranges R(m) are compared with ranges R(0) calculated with a current version of the Bethe theory. For light absorbers (atomic number Z < 20), differences between R(m) and R(0) are less than +/-0.3 mm; for Z > 20 differences are between 0 and +/-0.6 mm. This agreement between calculated and measured ranges confirms the value I = 80 eV for water measured earlier for protons. The ionization by nuclear fragments is obtained from the difference between measured and calculated ionization functions, and has little influence on the ranges of the primary ions.

Electrons↗
PubMed1999

A human homolog of Drosophila warts tumor suppressor, h-warts, localized to mitotic apparatus and specifically phosphorylated during mitosis.

We identified a human homolog of Drosophila warts tumor suppressor gene, termed h-warts, which was mapped at chromosome 6q24-25.1. The h-warts protein has a serine/threonine kinase domain and is localized to centrosomes in interphase cells. However, it becomes localized to the mitotic apparatus, including spindle pole bodies, mitotic spindle, and midbody, in a highly dynamic manner during mitosis. Furthermore, h-warts is specifically phosphorylated in cells at mitotic phase, most likely by Cdc2 kinase. These findings suggest that h-warts functions as a component of the mitotic apparatus and is involved in proper progression of mitosis.

Amino Acid Sequence↗