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Biomedical subjects

N Nakata

Publications and source records attributed to N Nakata.

At least 19 recordsLinked to original sources
PubMed2006

Molecular cytogenetic analyses of hexaploid lines spontaneously appearing in octoploid Triticale.

Genome characterization of 14 hexaploid lines that spontaneously appeared in octoploid Triticales was carried out by sequential genomic in situ hybridization and fluorescence in situ hybridization, high molecular weight glutenin subunits and SSR marker analyses. All of the lines showed a chromosome constitution of complete A and B genomes, and a composite genome consisting of the chromosomes of D and R genomes. The composite genome of the 11 lines consisted of chromosomes 1R, 2D, 3R, 4R, 5R, 6R and 7R, that of the two lines were 1D, 2D, 3R, 4R, 5R, 6R and 7R, and that of one line was 1R, 2D, 3R, 4R, 5R, 6D and 7R. The incompatibility of the D and R genomes in common wheat genetic background, preferential retention of chromosome 2D and importance of these lines for the development of hexaploid Triticale are discussed in this report.

Chromosomes, Plant↗
PubMed2001

PC reporting system for radiologists: practical use under PACS environment.

To evaluate the practical usefulness of several types of the reporting system especially for radiologists, we have developed and employed several reporting systems. We categorized those reporting systems as follows (1) stand alone PC reporting system; (2) linked reporting system with PACS environment; (3) integrated three-dimensional (3D) imaging workstation (WS) with the intranet. We have evaluated the advantages and disadvantages of those three systems, and compared between the reporting system without PACS and network reporting system with PACS. Using linked reporting system with PACS, radiologists could easily reference both previous reports and archived diagnostic images, and also make their teaching files quickly. In conclusion, the reporting system under PACS environment is found to be practical and helpful for Japanese radiologists.

Humans↗
PubMed2001

Ultrasound virtual endoscopic imaging.

Volume data acquisition, three dimensional (3D) imaging, and multiplanar reformatting have become widely used for computed tomography (CT) and magnetic resonance imaging (MRI). As an extension of this technology, virtual endoscopic visualization of hollow organs has become a reality that is now finding its way into clinical CT practice. The same methods of computer processing as are used for CT and MRI can be applied to an ultrasound (US) volume image data set with the same potential output; namely, 3D, multiplanar, and virtual endoscopic images. The use of this image processing technology for US applications has lagged behind the CT and MRI applications, but considerable progress in applying these methods to US has occurred in recent years. As a result, US virtual endoscopic imaging now can be performed on a clinical basis by using standard US instruments and commercially available computer software. The use of newer US imaging methods, such as tissue harmonic and power Doppler imaging, has enhanced the potential for US virtual endoscopy. This article reviews the technology of US virtual endoscopy. In addition, our preliminary experience of using this method for abdominal and vascular diagnosis is described. Finally, we speculate on technical improvements and potential applications that are likely in the future.

Acoustics↗
PubMed2001

Multidrug resistant Mycobacterium leprae from patients with leprosy.

Sequences of the folP1, rpoB, and gyrA genes were analyzed for 88 isolates of Mycobacterium leprae from leprosy patients in Japan, Haiti, Indonesia, Pakistan, and the Philippines. Thirteen isolates (14.8%) showed representative mutations in more than two genes, suggesting the emergence of multidrug-resistant M. leprae.

Animals↗
PubMed2001

[Genome features of Mycobacterium leprae].

Recent studies have revealed that the Mycobacterium leprae genome contains many pseudogenes. This short review summarizes the structural features of the M. leprae genome and genes.

Base Sequence↗
PubMed2000

Molecular basis of clarithromycin-resistance in Mycobacterium avium intracellulare complex.

Nucleotide sequences of domain V and domain II regions of the 23S rRNA gene were determined in both in vitro-made mutants and clinical isolates of Mycobacterium avium and M. intracellulare conferring clarithromycin-resistance. All laboratory-made mutants showed high level resistance to clarithromycin (> 150 micrograms ml-1) and mutation at position 2058 (cognate with Escherichia coli base) in domain V region. In the clinical isolates, while the susceptible ones had no mutation in domain V, the resistant strains showed mutation at 2058 or 2059. Six isolates with low level of resistance exhibited no mutation in domain V. All strains tested had no mutation in domain II region. These results suggested that most of the resistance arose from the mutation in domain V of the 23S rRNA gene, but other unknown mechanisms evidently exist in mycobacteria.

Anti-Bacterial Agents↗
PubMed2000

Detection of QTLs for heading time and photoperiod response in wheat using a doubled-haploid population.

The genetic basis of heading time in wheat (Triticum aestivum L.) was investigated through the study of flowering under normal autumn sown field conditions as well as photoperiod responses under a controlled environment. Quantitative trait loci (QTLs) for these traits were mapped in a doubled-haploid (DH) population derived from a cross between the wheat cultivars 'Courtot' and 'Chinese Spring'. A molecular marker linkage map of this cross that was previously constructed based on 187 DH lines and 380 markers was used for QTL mapping. The genome was well covered (85%) except for chromosomes 1D and 4D, and a set of anchor loci regularly spaced over the genome (one marker each 15.5 cM) was chosen for marker regression analysis. The presence of a QTL was declared at a significance threshold of alpha = 0.005. The population was grown under field conditions in Clermont-Ferrand, France during two years (1994-1995), in Norwich, U.K. over one year (1998), and also under controlled environments in Norwich. For each trait, between 2 and 4 QTLs were identified with individual effects ranging between 6.3% and 44.4% of the total phenotypic variation. Two QTLs were detected that simultaneously affected heading time and photoperiod response. For heading time, these two QTLs were detected in more than one year. One QTL located on chromosome arm 2BS near the locus Xfbb121-2B, co-segregated with the gene Ppd-B1 known to be involved in photoperiod response. This chromosome region explained a large part of the variation (23.4-44.4% depending on the years or the traits). Another region located on chromosome arm 7BS between the loci Xfbb324-7B and Xfbb53-7B also had a strong effect (7.3-15.3%). This region may correspond to a QTL for earliness per se.

Chromosome Mapping↗
PubMed2000

Mycobacterium leprae typing by genomic diversity and global distribution of genotypes.

The genetic diversity and related global distribution of 51 Mycobacterium leprae isolates were studied. Isolates were obtained from leprosy patients from 12 geographically distinct regions of the world and two were obtained from nonhuman sources. Polymerase chain reaction (PCR) followed by DNA sequencing was performed targeting the rpoT gene of M. leprae. Isolates were classified into two groups based on the number of tandem repeats composed of 6 base pairs in the rpoT gene. Isolates from Japan (except Okinawa) and Korea belonged to one group, while those from Southeast Asian countries, Brazil, Haiti and Okinawa in Japan belonged to a second genotype. M. leprae obtained from two nonhuman sources (an armadillo and a mangabey monkey) revealed the latter genotype. These results demonstrate the genetic diversity of M. leprae and the related genotype-specific distribution in the world.

Bacterial Proteins↗
PubMed1999

Diaminodiphenylsulfone resistance of Mycobacterium leprae due to mutations in the dihydropteroate synthase gene.

The nucleotide sequence analysis of the dihydropteroate synthase (DHPS) gene of six diaminodiphenylsulfone-resistant Mycobacterium leprae strains revealed that the mutation was limited at highly conserved amino acid residues 53 or 55. Though the mutation at amino acid residue 55 or its homologous site has been reported in other bacteria, the mutation at residue 53 is the first case in bacteria. This is the first paper which links the mutations in DHPS and sulfonamide resistance in M. leprae. This finding is medically and socially relevant, since leprosy is still a big problem in certain regions.

Dapsone↗
PubMed1998

Breast masses: color Doppler, power Doppler, and spectral analysis findings.

PURPOSE: To determine the diagnostic efficacy of power Doppler sonography (PDS) with spectral analysis for breast diseases, we retrospectively compared PDS and color Doppler sonography (CDS) in patients with breast lesions. METHODS: One hundred thirty-eight women with palpable breast lesions were examined with PDS (65 women) and/or CDS (73 women). We calculated peak velocity, end-diastolic velocity, pulsatility index (PI), and resistance index (RI). RESULTS: On a 4-point subjective visual vascularity scale, PDS demonstrated higher vascularity than did CDS. Although smaller and more subtle vessels could be detected only with PDS, the PI and RI differed significantly between malignant and benign lesions when either PDS or CDS was used. However, logistic regression analysis showed that high PI and RI were associated with malignancy only when CDS was used. When PDS was used, PI was significantly higher in invasive ductal carcinomas with fibrous stroma and ill-defined margins (associated with a poor prognosis) than in invasive ductal carcinomas without fibrous stroma or with well-defined margins. CONCLUSIONS: Doppler spectral analysis of malignant breast lesions using PDS may contribute to the determination of prognosis.

Breast Neoplasms↗
PubMed1998

The possible role of interleukin (IL)-12 and interferon-gamma-inducing factor/IL-18 in protection against experimental Mycobacterium leprae infection in mice.

Cell-mediated immunity participates in host defense against mycobacterial infection. Both interleukin 12 (IL-12) and interferon-gamma-inducing factor (IGIF/IL-18), produced mainly by macrophages, play a critical role in expression of cell-mediated immunity. To investigate the role of IL-12 and IGIF/IL-18 in vivo, we examined cytokine profile, bacterial growth, and the potential benefit of cytokine therapy in susceptible and resistant mice infected with Mycobacterium leprae. The early expression of IL-12 p40 and IGIF/IL-18 at the site of inoculation was found in resistant mice 3-72 h after the infection, but not in susceptible mice. Both strains of mice did not show expression of IFN-gamma and IL-4. IL-12 administration resulted in a significant reduction of bacterial counts in mice with established M. leprae infection. The results imply that susceptible mice exhibit decreased expression of type 1 helper T (Th1) response without reciprocal increased Th2 response and show responsiveness to exogenous IL-12. IL-12 therapy may be a possible rationale for treatment of M. leprae infection.

Animals↗
PubMed1998

Comparison of effect of [D-Arg2,Sar4]-dermorphin (1-4) and morphine on mouse small intestinal transit and electrically evoked contraction of guinea pig ileum.

[D-Arg2,Sar4]-dermorphin (1-4) [DAS-DER (1-4)] was compared with morphine for the capacity to affect mouse gastrointestinal transit and electrically evoked contractions of the guinea pig ileum (GPI). A single subcutaneous injection with DAS-DER (1-4) and morphine dose-dependently inhibited gastrointestinal transit of charcoal in mice. DAS-DER (1-4) with ID50 of 0.053 mg/kg was 26 times more potent than morphine with ID50 of 1.38 mg/kg. The inhibitory effects of DAS-DER (1-4) and morphine were completely inhibited by pretreatment with 1 mg/kg naloxone, an opioid receptor antagonist. The GPI contraction was inhibited by DAS-DER (1-4) with an IC50 of 6.9 +/- 0.7 nM and morphine with an IC50 of 295.0 +/- 11.8 nM, respectively. These effects were also inhibited by preincubation with naloxone. Repeated subcutaneous injections of DAS-DER (1-4) and morphine to guinea pigs produced tolerance to the inhibitory effect on electrically evoked contractions of GPI. Moreover, a marked cross tolerance was seen in guinea pigs made tolerant to DAS-DER (1-4) or morphine. The present study indicates that pharmacological profiles of DAS-DER (1-4) as assayed by the gastrointestinal transit and stimulated contractions of the GPI were almost similar to that of morphine.

Analgesics, Opioid↗
PubMed1998

[Clinical usefulness of ultrasound (US) database and reporting system].

Our US database and reporting system is a relational database designed for US image-management and navigation through volumes of US images, ACR code, text and diagnostic reports. This program, running on a network of Unix servers and Macintosh clients, supports jukebox 5 inch optical disks for data storage. With simple keywords for ACR code, we can make a cross-reference and categorize US images of teaching files.

Data Display↗
PubMed1997

Decreased expression of cytokines that induce type 1 helper T cell/interferon-gamma responses in genetically susceptible mice infected with Mycobacterium avium.

Mycobacterium avium is an intracellular microorganism that infects and multiplies within macrophages. Cell-mediated immunity plays an important role in host defense. Two cytokines, interleukin 12 (IL-12) and interferon-gamma-inducing factor (IGIF), produced mainly by macrophages, are critical for the development of type 1 helper T (Th1) cell/interferon-gamma (IFN-gamma) responses and cell-mediated immunity. In this report, by using a mouse model of disseminated M. avium infection, we demonstrate that genetically susceptible BALB/c mice show decreased expression of IL-12 and IGIF in association with a diminished IFN-gamma/Th1 response. Conversely, resistant DBA/2 mice exhibited increased expression of IL-12, IGIF, and IFN-gamma. In both strains of infected mice, the level of IL-4/Th2 response was similar. These results suggest that decreased expression of IL-12 and IGIF leads to a diminished Th1 response without reciprocal enhanced Th2 responses in susceptible mice.

Animals↗
PubMed1997

Role of hippocampal serotonergic neurons in ischemic neuronal death.

To clarify the serotonergic mechanisms involved in the protection against ischemic neuronal damage, ZD-211 (citalopram HBr), a serotonin (5-hydroxytryptamine; 5-HT) re-uptake inhibitor, or buspirone, a 5-HT1A agonist, was locally administered into the hippocampus of gerbils. Additionally, to clarify the role of the 5-HT nervous system in the hippocampus during ischemic neuronal damage, animals were subjected to the local administration of 5,7-dihydroxytryptamine (5,7-DHT), a 5-HT neurotoxin, before ischemia challenge. Gerbils received intrahippocampal administration of ZD-211 (200 nmol/animal) or buspirone (20 nmol/animal) before 5-min ischemia. 5,7-DHT was intrahippocampally administered 7 days before a 2-min non-lethal ischemia challenge. In vehicle-treated animals subjected to 5 min of ischemia, almost all hippocampal CA1 pyramidal neurons were lost. The treatment with ZD-211 or buspirone showed a significant protective effect, and the number of neurons was significantly increased compared to vehicle-treated animals. Pretreatment with NAN-190, a 5-HT1A antagonist, completely abolished the protective effect of ZD-211 or buspirone. In the 5,7-DHT-treated animals, the number of neurons was significantly reduced following 2 min of ischemia compared to vehicle-treated animals in which this period of ischemia is non-lethal. Thus, intrahippocampal treatment with ZD-211 or buspirone can protect neuronal damage following transient ischemia in gerbils. These effects of ZD-211 and buspirone were mediated through the 5-HT1A receptor in the hippocampus. Furthermore, the destruction of the 5-HT nervous system in the hippocampus aggravated ischemic neuronal damage. Therefore, this study showed that the enhanced activity of the 5-HT nervous system in the hippocampus may protect against neuronal damage following cerebral ischemia.

5,7-Dihydroxytryptamine↗
PubMed1997

Nucleotide sequence of the Mycobacterium leprae katG region.

Synthetic oligonucleotide primers based on the DNA sequence data of the Escherichia coli, Mycobacterium tuberculosis, and Mycobacterium intracellulare katG genes encoding the heme-containing enzyme catalase-peroxidase were used to amplify and analyze the Mycobacterium leprae katG region by PCR. A 1.6-kb DNA fragment, which hybridized to an M. tuberculosis katG probe, was obtained from an M. leprae DNA template. Southern hybridization analysis with a probe derived from the PCR-amplified fragment showed that the M. leprae chromosome contains only one copy of the putative katG sequence in a 3.4-kb EcoRI-BamHI DNA segment. Although the nucleotide sequence of the katG region of M. leprae was approximately 70% identical to that of the M. tuberculosis katG gene, no open reading frame encoding a catalase-peroxidase was detectable in the whole sequence. Moreover, two DNA deletions of approximately 100 and 110 bp were found in the M. leprae katG region, and they seemed to be present in all seven M. leprae isolates tested. These results strongly suggest that M. leprae lacks a functional katG gene and catalase-peroxidase activity.

Bacterial Proteins↗
PubMed1997

[Multi-drug antiemetic treatment and effect of treatment duration of concurrent steroids--for complete control of chemotherapy-induced nausea/vomiting in gynecological cancer].

Antiemetic effect and safety of concurrent administration of ondansetron and other antiemetics (dexamethasone, domperidone and ethyl loflazepate), given for complete suppression of nausea/vomiting, were examined in 46 patients (109 courses) with gynecological cancer receiving single high-dose of cisplatin or carboplatin. As for the delayed emesis, antiemetic effect depending on the steroid treatment duration, given concurrently to ondansetron, was compared. The results were as follows; 1. In 78 courses, anticancer drugs were given concurrently to cisplatin or carboplatin only on Day 1. In the remaining 31 courses, those drugs were concurrently administered up to Day 6 at the longest. 2. Complete suppression (i.e., no onsets) rate of acute emesis was 64.2% (70/109 courses) for nausea, and 84.4% (92/109 courses) for vomiting. 3. When the complete suppression depending on duration of concomitant steroid was examined mainly in patients receiving CAP (cyclophosphamide, adriamycin and cisplatin), higher antiemetic effect, especially in nausea, was observed in those on concomitant steroids for 3 days compared to that for 1 day. 4. The food intake rate improved along with nausea symptoms. 5. No adverse event or laboratory abnormality due to the multi-antiemetic treatment was observed. Based on the above, the efficacy of the antiemetic treatment in this study was confirmed. In delayed emesis, concurrent steroids given for 3 days after chemotherapy were considered effective and were also regarded to improve food intake.

Administration, Oral↗