Search PubMed⌕ Search

Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 289 records · Page 16Linked to original sources
PubMed1996

Screening of antipsychotic drugs by wide-bore capillary gas chromatography with nitrogen phosphorus detection--detection levels in plasma.

The detection levels of 12 antipsychotic drugs as ascertained from drug screening were examined in order to use the screening results effectively for treatment of patients or medico-legal examinations in cases of poisoning. Wide-bore capillary gas chromatography with nitrogen phosphorus detection was used for the analysis. The detection limits of drugs in plasma using 3 extraction procedures, single-solvent, 3-step solvent and solid-phase extractions were 50-100 ng/ml, 10-200 ng/ml and 5-50 ng/ml, respectively. The detection limits were compared with blood levels previously reported in the literature. Only 4 drugs were detected at the therapeutic level, thioridazine, floropipamide, sultopride and oxypertine using the single-solvent extraction procedure. Using the 3-step solvent extraction procedure, chlorpromazine, levomepromazine and zotepine in addition to the above 4 drugs were detected. Using the solid-phase extraction procedure, 8 of 12 drugs were able to be detected at the therapeutic level, with the exception of perphenazine, haloperidol, bromperidol and nemonapride. These data were proved to be useful for a rapid forensic diagnosis.

Antipsychotic Agents↗
PubMed1996

Optic sharp edge or convexity: comparison of effects on posterior capsular opacification.

Posterior capsular opacification was evaluated in 46 eyes with an implanted sharp-edged biconvex (BC) lens, 108 eyes with the sharp-edged convex-plano (CP) lens, 160 eyes with the round-edged BC lens and 58 eyes with the round-edged CP lens. In each eye, the intraocular lens had been fixed in the sac after continuous circular capsulorrhexis, with the optic edge completely enclosed by the anterior capsule. Two years postoperatively, the posterior capsules of these eyes were photographed and the degree of opacification was classified as Grade 1 (clear) to Grade 4 (severely opacified). In the sharp-edged BC group, 91% of the eyes were Grade 1; 4% Grade 2; 2% Grade 3; 2% Grade 4. In the sharp-edged CP group, the corresponding percentages were 83, 7, 4, and 6; for the round-edged BC group: 18, 27, 24, and 31; and for the round-edged CP group: 34, 17, 28, and 21. These findings suggest that the most significant factor in prevention of posterior capsular opacification is the sharpness of the optic edge. We believe that the sharp optic edge creates higher pressure on the posterior capsule and acts as a barrier to lens epithelial cell migration.

Aged↗
PubMed1995

Regulation of the mouse histone H2A.X gene promoter by the transcription factor E2F and CCAAT binding protein.

We have molecularly cloned the genomic gene encoding the mouse histone variant H2A.X and characterized the promoter. The promoter region of the H2A.X gene was characterized by chloramphenicol acetyltransferase analysis using Balb/c 3T3 cells. Maximal promoter activity was found in the construct containing up to -282 base pairs H2A.X upstream region. Within this region, we found two sequences regulating the promoter activation; one was an E2F site and another was a CCAAT box. These sequences were also required for the DNA/protein binding activities. Thus, these activities corresponded to the promoter activities, implying that the promoter activity H2A.X gene was controlled by both the transcription factor E2F and H1TF2 through the E2F and CCAAT element. The CCAAT box binding activity was constitutive when cell cycle was progressed by release from G1 arrest, but transiently transfected chloramphenicol acetyltransferase activity slightly increased when cells entered S phase. Similarly, the level of the smallest form of E2F (free E2F) became higher when cells reentered the cell cycle, indicating that the free E2F was one capable of inducing the promoter activation. Thus, the free E2F and CCAAT DNA binding activity correlated with regulation of the promoter activity.

3T3 Cells↗
PubMed1995

Identification of auxin-responsive elements of parB and their expression in apices of shoot and root.

Detailed analysis of transgenic tobaccos containing a series of chimeric parB promoter/beta-glucuronidase (GUS) gene constructs allowed us to define two auxin-responsive elements (AREs) of 48 bp and 95 bp (positions -210 to -163 and -374 to -280) in the parB promoter. The two AREs responded independently to physiological concentrations of auxin. Gel retardation assays revealed binding of nuclear protein(s) to the sequence conserved between ARE I and ARE II. The auxin responsiveness of the parB promoter did not mediate the pathway through the as-1 element and transcription factor ASF-1. AREs I and II were responsive to auxin at physiological concentrations, whereas as-1 responded only to higher concentrations of auxin which may be interpreted as stress, though as-1 had been reported to be a minimal ARE [Liu, X. & Lam, E. (1994) J. Biol. Chem. 269, 668-675]. Histochemical staining of transgenic tobacco that contained a parB promoter/GUS construct demonstrated the expression of GUS activity in the shoot apex as well as in the root tips, suggesting the involvement of parB expression in meristematic activity or differentiation. The drastic change in auxin responsiveness in the transgenic plants between the 6th and 10th day after imbibition of seeds implies the development or the activation of auxin signal transduction systems during plant development.

Bacterial Proteins↗
PubMed1995

Immunogold studies on peroxisomes: review of the localization of specific proteins in vertebrate peroxisomes.

Peroxisomes, since their discovery as microbodies, have been studied mostly independently by electron microscopists and biochemists. The fine structure has been studied by electron microscopy, and the compositional enzymes and proteins by protein biochemistry. Electron microscopic histochemistry has been used to try to clarify the relationship between the fine structure and its constituents. The immunogold technique, a combination of electron microscopy and protein biochemistry, for the first time resolved this problem due to the high sensitivity and resolution power of the staining and the high reliability of the technique. The present paper reviews the way in which the immunogold techniques, especially the protein A-gold technique, revealed the localization of various enzymes or proteins in peroxisomes or peroxisomal subcompartments, and discusses why this technique should be employed in peroxisome research.

Animals↗
PubMed1995

Regulation of osteopontin expression in osteoblasts.

Osteopontin (OPN) is a prominent bone matrix protein that is synthesized by osteoblastic cells. To elucidate the function of OPN in bone we studied the regulated expression of the rat OPN protein during bone formation in vivo and in vitro. OPN mRNA is expressed by preosteoblastic cells early in bone formation, but the highest expression is observed in mature osteoblasts at sites of bone remodelling. A low-phosphorylated, 55-kDa form of OPN is produced by the preosteoblastic cells, whereas osteoblasts produce a highly phosphorylated, 44-kDa protein; the two forms of OPN corresponding to pp69 and pp62 in transformed rat cells. The synthesis of the 55-kDa OPN correlates with the formation of a 'cement' matrix that is synthesized prior to bone deposition, whereas the 44-kDa OPN synthesized by osteoblasts associates rapidly with hydroxyapatite, possibly regulating crystal growth, and may also provide a substratum for osteoclast attachment. Expression of OPN mRNA is upregulated by growth and differentiation factors (PDGF, EGF, TGF-beta and BMP-7/OP-1) and by mechanical stress, which promote bone formation, as well as by osteotropic hormones (retinoic acid and vitamin D3), which can promote bone resorption and remodelling. However, OPN mRNA is down-regulated by bisphosphonates, which abrogate bone resorption. Regulation of OPN expression is, therefore, consistent with a multiplicity of functions for OPN that involve specific structural motifs in both the synthesis and resorption of bone.

Amino Acid Sequence↗
PubMed1995

Physical mapping of the retinoid X receptor B gene in mouse and human.

Retinoid X receptors (RXRs) are zinc finger-containing nuclear transcription factors. They belong to the nuclear receptor superfamily that contains retinoid receptors, vitamin D receptors, thyroid hormone receptors, and steroid hormone receptors as well as the so-called orphan receptors. We previously mapped all three RXR genes on mouse chromosomes, using a panel of Mus spretus-Mus musculus interspecific backcross mice: Namely, the RXRA-gene (Rxra) on Chr 2 near the centromere, the RXRB gene (Rxrb) on Chr 17 in the H2 region, and the RXRG gene (Rxrg) on distal Chr 1. Using cosmid clones that cover the major histocompatibility complex (MHC) region, we determined the precise physical map positions of the gene encoding mouse and human RXRB, respectively. The mouse gene (Rxrb) maps between H2-Ke4 and H2-Ke5: namely, immediately telomeric to H2-Ke4 which encodes a histidine-rich transmembrane protein, and 12 kilobases centromeric to H2-Ke5 which is expressed in lymphoid tissues. Rxrb and H2-Ke4 are transcribed into opposite directions from a CpG-rich promoter of about 250 base pairs. This gene organization is well conserved also in the human genome at the HLA-DP subregion of Chr 6p, underscoring the strong conservation of the gene organization in the MHC region between the two mammals.

Animals↗
PubMed1995

Expression of the auxin-regulated parA gene in transgenic tobacco and nuclear localization of its gene products.

An auxin-regulated gene, parA, comprises a gene family consisting of a handful genes which respond to various signals. Although Droog et al. (Plant Mol. Biol, 1993, 21, 965-972) postulated that the parA-related genes belong to the family of a cytoplasmic enzyme, glutathione S-transferase (GST), we detected a low level of GST activity in the parA products, whose value was below 1/30 of that of parB products encoding tobacco (Nicotiana tabacum L.) GST. Immunofluorescence studies using an antibody against parA protein revealed that the subcellular location of parA protein is the nucleus in cultured tobacco mesophyll protoplasts, while conventional GSTs' including the parB product were primarily located in the cytoplasm. Confocal laser scanning microscopy of tobacco BY-2 cells showed that the parA product was confined to the nucleus, but was excluded from the nucleolus. In addition, exon/intron organization of the parA family was appreciably different from that of conventional GSTs including parB. Furthermore, the parA protein is much more similar to a 24-kDa protein of Escherichia coli that is reported to bind to RNA polymerase. These different characteristics of parA compared with to the conventional GSTs, indicate that parA protein would have distinct functions, such as involvement in transcription, rather than functioning as a conventional GST. Transgenic tobacco plants that carried the parA promoter fused to a beta-glucuronidase gene were used to show that the parA gene is tissue-specific and also under developmental control.

Amino Acid Sequence↗
PubMed1995

Nosocomial propagation of multiresistant Staphylococcus aureus: an analysis using biotyping and drug sensitivity.

We performed an epidemiologic study of multi-resistant Staphylococcus aureus in our hospital. We combined bacteriologic biotyping and sensitivity to 19 drugs to conduct an environmental investigation. We assumed that complete matching in two or more strains denoted nosocomial propagation. A total of 667 isolates were recovered from a total of 144 patients. In a general surgical ward, 19 (52.8%) out of 36 patients developed an infection. The number of strains for every biotype and the combined susceptibility tended to show negative correlation (r = -0.376) before and after 1990, when an isolation policy was initiated. A similar regression analysis disclosed that between the general surgical ward and other wards the number of strains tended to show a positive association (r = 0.349). Thus, the isolation system employed in the general surgical ward may have arrested the persistence of intraward strains but permitted the interward travel of strains. In conclusion, an analysis of the propagation of multiresistant S. aureus using biotyping and drug sensitivity was found to be an effective method for evaluating the most appropriate measures to counter the endemic spread of this microbe.

Anti-Bacterial Agents↗
PubMed1995

Limited value of interictal brain perfusion SPECT for detection of epileptic foci: high resolution SPECT studies in comparison with FDG-PET.

Accurate localization of epileptic foci is important for pre-surgical evaluation of patients with medically intractable epilepsy, and F-18 FDG PET has been proved to be a valuable method for this purpose. To examine the clinical value with interictal brain perfusion SPECT, we performed brain perfusion SPECT of Tc-99m HMPAO by means of a high resolution SPECT camera, and compared the results with F-18 FDG PET images and MRI in 10 patients with medically intractable epilepsy. In 9 of 10 patients (90%), FDG PET images showed focal hypo-metabolism in the area corresponding with the results of electroencephalography (EEG). SPECT images, however, demonstrated hypo-perfused lesions which corresponded with hypo-metabolic lesions on FDG PET images in only 6 cases (60%). Although MRI showed abnormal findings in 8 cases, the lesions were not directly related to epileptic foci in 2 cases. In conclusion, FDG PET is a valuable tool for accurate localization of epileptic foci. Brain perfusion SPECT, however, may not always be paralleled to metabolism visualized on FDG PET images.

Adolescent↗
PubMed1995

Identification of osteopontin in human dental calculus matrix.

Osteopontin is a prominent non-collagenous component of bone matrix, although it is expressed in several other tissues. Recently, osteopontin was reported to be involved in urinary stone formation and atherosclerotic lesions of the aorta, suggesting that it may be a key protein associated with these types of pathological mineralization. In this study, whether or not human dental calculus contains osteopontin was investigated by immunoblotting and immunohistochemical analyses. After extraction of calculus proteins with EDTA and separation of the proteins by electrophoresis, immunoblotting analysis revealed the presence of osteopontin. Two forms of osteopontin appeared at 61 and 68 kDa on 10% polyacrylamide gel and the proteins were digested with thrombin, a highly specific protease. Moreover, immunohistochemical analysis revealed that osteopontin was localized in dental calculus adherent to tooth roots. These findings indicate that osteopontin is, in fact, present in human dental calculus and may be involved in calculus formation as the stone matrix.

Dental Calculus↗
PubMed1995

[125I]iomazenil binding in the brains of spontaneously epileptic rats: an ex vivo quantitative autoradiographic study.

Central benzodiazepine receptor binding was studied in spontaneously epileptic rats (SER) and in their parent strain. Kyoto-Wistar (KW) rats, by ex vivo quantitative autoradiography with [125I]iomazenil. Thirteen-week-old SER developed tonic and absence-like seizures following mild stimulation by tapping at 5 min before injection of the radioligand. When compared with age-matched KW rats, a significant 76% elevation of radioactivity was observed in the SER hippocampus, while there was no difference in hippocampal blood flow obtained using [125I]N-isopropyl-p-iodoamphetamine. Since benzodiazepine receptors act to enhance inhibitory GABA transmission, this finding suggests a possible mechanism for seizure-induced enhancement of inhibition.

Animals↗
PubMed1995

Reliability and validity of the Japanese version of the Yale-Brown Obsessive-Compulsive Scale.

The reliability and validity of the Japanese version of the Yale-Brown Obsessive-Compulsive Scale (JY-BOCS) were determined by 20 raters for 12 Japanese patients with obsessive compulsive disorder at four institutions. Interrater reliability for the total JY-BOCS score was excellent, and the intraclass correlation coefficient was high (ICC = 0.960). Internal consistency was also excellent (Cronbach's alpha = 0.889). Concurrent and discriminant validity of the JY-BOCS was examined by comparing the scores on the JY-BOCS with those on the Maudsley Obsessional Compulsive Inventory (MOCI) and scales for depression and anxiety. A slight correlation was found between scores on the JY-BOCS and MOCI, but no significant correlations were found between scores on the JY-BOCS and those on scales for depression or anxiety.

Adult↗
PubMed1995

Successful autologous bone marrow transplant for relapsed Ki-1 lymphoma.

We report on a 16 year old girl with relapsed Ki-1 lymphoma and a very poor prognosis. The initial manifestation was multiple bone metastases and lymphadenopathy. The patient achieved remission with modified adriamycin, bleomycin, vincristine, daunomycine therapy. However, 14 months after the completion of therapy, relapse occurred in a new cervical lymph node on the left side. After preparation with chemotherapy and total lymphoid irradiation (TLI) the patient underwent autologous bone marrow transplantation (A-BMT). Ki-1 lymphoma shows clinically diverse symptoms, but hematopoietic stem cell transplantation should be performed in relapsed cases. It may be effective to give TLI followed by A-BMT for patients such as ours who have lymph node involvement without bone marrow metastasis.

Adolescent↗