Search PubMed⌕ Search

Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 163 records · Page 9Linked to original sources
PubMed1999

Distribution of osteopontin and calprotectin as matrix protein in calcium-containing stone.

We recently reported that osteopontin (OPN) and calprotectin (CPT) are present in the matrix of urinary calcium stones, and that OPN mRNA is expressed in the renal distal tubular cells. In the present study, we examined the immunohistochemical distributions of OPN and CPT in urinary stones. The stones used in this study were passed spontaneously from the upper urinary tract. One half of each of the stones was analyzed with an infrared spectrophotometer, and were shown to be comprised of calcium oxalate, calcium phosphate, uric acid and cystine. The other half of each stone was immersed in tetrasodium ethylenediamine-tetraacetate (EDTA) solution. The half-stones were embedded in paraffin and cut into 5-microm sections. The avidin-biotin-peroxidase complex technique was employed. A monoclonal antibody to human milk-derived OPN and a monoclonal antibody to human granulocyte-derived CPT were used as primary antibodies. The immunochemical study using the OPN and CPT antibodies showed positive staining of the matrix of the urinary calcium stones. The stones showed staining in two distinct zones: a core area was stained with randomly aggregated OPN and CPT, and peripheral layers were stained in concentric circles. On the basis of our observations, it is reasonable to presume that OPN and CPT play roles as the matrix in the structure of urinary calcium stones.

Animals↗
PubMed1999

Polychlorinated dibenzo-p-dioxins and related compounds: correlations of levels in human tissues and in blood.

We investigated PCDDs and related compounds levels in human tissue and blood obtained from the general population, and the correlation factor was calculated from the findings. None of the congeners in brain, muscle and lung were correlated except for 2,3,7,8-tetrachlorodibenzo-p-dioxin and octachlorodibenzo-p-dioxin in the brain (p < 0.05). In other tissues, all congeners had relatively good correlations to those in blood (r > 0.707). These congeners detected in blood were at high concentrations in the environment and human body. Therefore, we concluded that these congener levels in the blood might be useful for estimating these congener levels in human tissue.

Adult↗
PubMed1999

Effect of retinoic acid on osteopontin expression in rat clonal dental pulp cells.

We studied the effect of retinoic acid on osteopontin synthesis and the mRNA expression in rat clonal dental pulp cells, RPC-C2A. An immunoprecipitation assay clarified that retinoic acid caused an increase in phosphorylated osteopontin synthesis that was dose-dependent, and marked increases were observed at retinoic acid concentrations of 10(-6) to 10(-5) M (1.7-fold). A Northern blotting analysis revealed a similar pattern of increase in osteopontin mRNA expression of up to 6.2-fold of control levels. Because osteopontin has an important role in the mineralization process, these results suggest that retinoic acid regulates mineralization, which takes place in the pulp cavity, including reparative dentin formation.

Animals↗
PubMed1999

Putative involvement of a 49 kDa protein in microtubule assembly in vitro.

In higher plant cells, thus far only a few molecules have been inferred to be involved in microtubule organizing centers (MTOCs). Examination of a 49 kDa tobacco protein, homologous to a 51 kDa protein involved in sea urchin MTOCs, showed that it also accumulated at the putative MTOC sites in tobacco BY-2 cells. In this report, we show that the 49 kDa protein is likely to play a significant role in microtubule organization in vitro. We have established a system prepared from BY-2 cells, capable of organizing microtubules in vitro. The fraction, which was partially purified from homogenized miniprotoplasts (evacuolated protoplasts) by salt extraction and subsequent ion exchange chromatography, contained many particles of diameters about 1 micron after desalting by dialysis. When this fraction was incubated with purified porcine brain tubulin, microtubules were elongated radially from the particles and organized into structures similar to the asters observed in animal cells, and therefore also termed "asters" here. Since we could hardly detect BY-2 tubulin molecules in this fraction, the microtubules in "asters" seemed to be solely composed of the added porcine tubulin. Tubulin molecules were newly polymerized at the ends of the microtubules distal to the particles, and the elongation rate of microtubules was more similar to the reported rate of the plus-ends than that of the minus-ends in vitro. By fluorescence microscopy, the 49 kDa protein was shown to be located at the particles. Thus, its location at the centers of the "asters" suggests that the protein plays a role in microtubule organization in vitro.

Animals↗
PubMed1999

The study of heat stress in tomato fruits by NMR microimaging.

The ripening of the tomato fruit was delayed for several days (average 5 days) by a 1-day heat treatment at 42 degrees C. Ethylene production increased during the first 3 h, but, after 6 h inhibition was almost total in tomato fruit incubated at 42 degrees C. However, recovery of ethylene production was rapid if fruits were returned to a temperature of 25 degrees C after heating. In NMR microimaging, three imaging pulse sequences with different repetition and echo times at 42 degrees C were used to obtain the proton density (TR = 6000 ms, TE = 15 ms), the T1 weighted image (TR = 1000 ms, TE = 15 ms) and the T2-weighted image (TR = 6000 ms, TE = 120 ms). After 12 h heating, the water in locular tissues began to show shorter T1 and T2 values. Though the tomatos were returned to 25 degrees C and preserved one more day, the water having a shorter T2 value in locular tissues, did not change. These results show that tomato fruit do not fully recover from heating even after one day, although ethylene production is recovered almost immediately. For this reason, we suggest that some denaturation event inside the tomato, which goes on after the end of heating, is the cause of the delay in tomato ripening.

Carbon Dioxide↗
PubMed1999

Examination of the roots of paramolar tubercles with computed tomography: report of 3 cases.

Computed tomography was used to examine root anatomy in 3 cases of paramolar tubercles. The images clearly showed the structure of the paramolar tubercles, including their root canal morphology. The root of the paramolar tubercle was united with the distobuccal root in each case. Canals were observed in all tubercles and were connected with the canals in distobuccal roots at various levels. In one case, the imaging information was helpful for endodontic treatment. The clinical importance of knowledge of the root and canal anatomy of these paramolar tubercles is discussed.

Adult↗
PubMed1999

Stimulatory effects of phenytoin on osteoblastic differentiation of fetal rat calvaria cells in culture.

Phenytoin (diphenylhydantoin, DPH), an anticonvulsant drug for epileptic patients, has several adverse effects, including calvarial thickening and coarsening of the facial features, which occur with chronic DPH therapy. While previous studies have demonstrated that DPH has an anabolic action on bone cells in vivo and in vitro, the basis of these effects is not fully understood. In this study, the effect of DPH on osteoblastic differentiation of fetal rat calvaria (RC) cells in culture was investigated by measuring bone nodule (BN) formation, cell growth, alkaline phosphatase (ALPase) activity, collagen synthesis, and expression of osteocalcin (OC) and osteopontin (OP) mRNAs. Continuous treatment of RC cells with DPH for 18 days dose-dependently increased the mineralized BN number by 1.2-1.7-fold at concentrations of 12.5-200 micromol/L DPH. Cell growth was not affected at the same concentrations of DPH. ALPase activity was stimulated by DPH (1.1-1.9-fold) dose-dependently and was maintained at higher levels in DPH-treated cells throughout the experimental period. DPH increased mineralized and unmineralized BN formations both in the presence and the absence of 10(-8) mol/L dexamethasone (Dex). Expression of OC and OP mRNAs was markedly augmented by DPH on days 12-24 and on days 12-18, respectively. While control mRNA levels of OC and OP increased with time, the increases in DPH-treated cells were greater than those of the controls and the stimulatory effects were dose-dependent. Type I collagen was also influenced by DPH; mRNA level was enhanced and the percentage of collagen synthesized was increased significantly, by 200 micromol/L DPH. When DPH was added in three different culture stages, days 1-6 (growth), days 7-12 (matrix development), and days 13-18 (mineralization), BN formation was influenced primarily on days 1-6 and secondarily on days 7-12, but not on days 13-18, suggesting that DPH increased BN formation by enhancing not only the proportion of osteoprogenitor cells in the early stage but also the proportion of functional osteoblasts in the middle stage within mixed-cell populations. Moreover, such increases were detected in conditions of both Dex(+) and Dex(-). These findings demonstrate that DPH stimulates osteoblast-associated markers such as BNs, ALPase, OC, OP, and type I collagen by continuously affecting the stages of growth and matrix development in RC cells, and suggests that the stimulatory effects by DPH may possibly be induced independent of those by Dex.

Alkaline Phosphatase↗
PubMed1999

History of childhood sexual or physical abuse in Japanese patients with eating disorders: relationship with dissociation and impulsive behaviours.

BACKGROUND: Empirical data regarding prevalence of sexual and physical abuse histories in Japanese patients with eating disorders is lacking, in contrast to Western countries. This study investigated the prevalence of traumatic events in Japanese patients with eating disorders, and examined the relationship between such traumatic events and clinical features. METHODS: Subjects consisted of 33 patients with anorexia nervosa restricting type (RAN), 40 patients with anorexia nervosa binge eating/purging type (AN-BP), 63 patients with bulimia nervosa purging type (BN) and 99 healthy controls. All were female and diagnoses were based on DSM-IV. The Physical and Sexual Abuse Questionnaire (PSA), Eating Disorder Inventory (EDI) and Dissociation Experience Scale (DES) were administered to all of the subjects. RESULTS: Paradoxically, victims of minor sexual abuse committed by Chikan (a Japanese word indicating a person who commits minor sexual crimes) were more prevalent among controls than among patients with RAN, AN-BP or BN. However, physical punishment histories tended to be more prevalent among patients with AN-BP or BN than among RAN or controls. Only AN-BP and BN patients with physical punishment histories had twofold higher scores for DES and significantly more frequent histories of self-mutilation (67% v. 33%) compared with patients without such histories. CONCLUSION: An abuse history is not essential or a prerequisite to developing an eating disorder in Japan.

Adolescent↗
PubMed1999

Mumefural, citric acid derivative improving blood fluidity from fruit-juice concentrate of Japanese apricot (Prunus mume Sieb. et Zucc).

The effects of food components on blood fluidity were studied by in vitro assay using a dedicated microchannel instrument for model capillaries. We found that the fruit-juice concentrate of the Japanese apricot (Prunus mume Sieb. et Zucc), a traditional Japanese food, markedly improved the fluidity of human blood. Using HPLC, we isolated the active compounds and characterized them using UV, MS, IR, and NMR. They included a novel compound, 1-[5-(2-formylfuryl)methyl] dihydrogen 2-hydroxypropane-1,2, 3-tricarboxylate (mumefural), and a related compound, 5-hydroxymethyl-2-furfural (HMF). Mumefural markedly improved blood fluidity in all subjects, while HMF worked differently in different individuals. The flow rate of blood spiked with mumefural or HMF was compared to that of the two predominant organic acids in the fruit. Citric acid, malic acid, and furfuryl alcohol also improved fluidity in all subjects. The activity of P. mume is derived from not only artifacts produced during thermal processing, such as mumefural, but also from endogenous organic acids.

Beverages↗
PubMed1999

Extraction and identification of antioxidants in the roots of yacon (Smallanthus sonchifolius).

Yacon, Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson, Asteraceae, an important economic species grown for its juicy tuberous root, is potentially beneficial in the diet to diabetics. The antioxidative activity of yacon root was studied by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay. Antioxidants were extracted by methanol and isolated and purified by gel permeation chromatography and preparative reverse-phase HPLC. Two of the major antioxidants were identified as chlorogenic acid and tryptophan by NMR and mass spectrometry.

Antioxidants↗
PubMed1999

Plant cell biology through the window of the highly synchronized tobacco BY-2 cell line.

Synchronous cell systems are highly desirable for investigating various aspects of plant cell biology. However, to date, the tobacco BY-2 cell line is the only plant cell line which can be synchronized to high levels. A cell synchrony starting from S phase is obtained after release of BY-2 cells from aphidicolin treatment, while that from M phase is available after release from a sequential treatment of aphidicolin followed by propyzamide. A high level of synchrony is only attained by using rapidly growing tobacco BY-2 cells that propagate ca. 100-fold in a week. Reduced levels of synchrony result if the growth rate becomes lower. Technical notes for maintaining the high growth rate of the tobacco BY-2 cell are described. Using this highly synchronous system it has been possible to demonstrate the cell cycle-dependent oscillation of many genes, such as cyclins, and characterize their role during the cell cycle. Furthermore, this system has facilitated the structural and biochemical analysis of cell cycle specific events such as the development of the phragmoplast and the formation of cortical microtubules. Other potential uses of this highly synchronized cells are also described.

Cell Line↗
PubMed1999

Calprotectin in gingival crevicular fluid correlates with clinical and biochemical markers of periodontal disease.

Clinical and biochemical markers of periodontal disease have been used for precise objective diagnosis of periodontal inflammation. Interleukin 1beta (IL-1beta) and prostaglandin E2 (PGE2), inflammatory factors, levels in gingival crevicular fluid (GCF) of patients with periodontal disease are elevated and have been studied as biochemical markers. The levels of calprotectin, a leukocyte protein, in body fluids of patients with some inflammatory diseases are raised. Recently, we detected calprotectin in GCF and its concentrations in periodontal pockets were higher than those in healthy gingival crevices. In this study, we investigated the correlations between GCF calprotectin levels and clinical indicators (probing depth and bleeding on probing, BOP), and the IL-1beta or PGE2 levels in GCE Probing depth and BOP at 130 sites of 110 subjects with periodontal or other oral diseases were examined, then GCF samples were collected and their calprotectin, IL-1beta and PGE2 were determined by ELISA. The calprotectin level correlated positively with the probing depth and was significantly higher at BOP-positive than BOP-negative sites. There were significant, positive correlations between the calprotectin and IL-1beta or PGE2 concentrations. These results indicate that the calprotectin level in GCF correlates well with clinical and biochemical markers of periodontal disease and suggest that calprotectin may be useful for evaluating the extent of periodontal inflammation.

Adult↗
PubMed1999

Immunoglobulin motif DNA recognition and heterodimerization of the PEBP2/CBF Runt domain.

The polyomavirus enhancer binding protein 2 (PEBP2) or core binding factor (CBF) is a heterodimeric enhancer binding protein that is associated with genetic regulation of hematopoiesis and osteogenesis. Aberrant forms of PEBP2/CBF are implicated in the cause of the acute human leukemias and in a disorder of bone development known as cleidocranial dysplasia. The common denominator in the natural and mutant forms of this protein is a highly conserved domain of PEBP2/CBF alpha, termed the Runt domain (RD), which is responsible for both DNA binding and heterodimerization with the beta subunit of PEBP2/CBF. The three-dimensional structure of the RD bound to DNA has been determined to be an S-type immunoglobulin fold, establishing a structural relationship between the RD and the core DNA binding domains of NF-kappaB, NFAT1, p53 and the STAT proteins. NMR spectroscopy of a 43.6 kD RD-beta-DNA ternary complex identified the surface of the RD in contact with the beta subunit, suggesting a mechanism for the enhancement of RD DNA binding by beta. Analysis of leukemogenic mutants within the RD provides molecular insights into the role of this factor in leukemogenesis and cleidocranial dysplasia.

Cleidocranial Dysplasia↗
PubMed1999

Activation of cyclin D1-related kinase in human lung adenocarcinoma.

Cyclin D1 gene amplification is an important event in many cancers, but it is rarely found in non-small-cell lung cancer (NSCLC). This study was conducted in an attempt to clarify any other mechanisms related to cyclin D1 involvement in the malignant transformation of NSCLC, and we clearly showed for the first time that cyclin D1-related kinases are activated in NSCLC, especially in adenocarcinoma but not in squamous cell carcinoma. The results of this study strongly suggest that enhanced cyclin D1-related kinase activity could contribute to a progression of adenocarcinoma in NSCLC.

Adenocarcinoma↗
PubMed1999

Co-ordinate expression of the pre-T-cell receptor complex and a novel immature thymocyte-specific antigen, IMT-1, during thymocyte development.

Previously we described a monoclonal antibody (mAb) that reacted with a cell-surface antigen, immature thymocyte antigen-1 (IMT-1), which is expressed on thymocytes of late CD4- CD8- (double negative) to early CD4+ CD8+ (double positive) differentiation stages. In this study, we investigated the expression of IMT-1 on various cell lineages in thymus as well as in peripheral lymphoid organs. We found that IMT-1 is expressed on T-cell receptor (TCR)-betalo and TCR-deltalo thymocytes, but not on TCR-betahi, TCR-deltahi or natural killer (NK)1.1+ thymocytes, or on peripheral alpha beta or gamma delta T cells. We also investigated the kinetics of expression of IMT-1 during fetal thymocyte development and compared it with the expression of the pre-TCR complex, comprising CD3, pre-TCR-alpha (pTalpha) and TCR-beta. We found that expression of both was similar, starting at day 14.5 of gestation, peaking on day 16.5 and gradually decreasing thereafter. Furthermore, the expression of both IMT-1 and pTalpha was drastically reduced when DN thymocytes in recombination activating gene (RAG)-2-/- mice were challenged in vivo with anti-CD3 mAb. These results indicate that IMT-1 is expressed on not only immature thymocytes of alpha beta T-cell lineage but also on those of gamma delta T-cell lineage, and that the expression of IMT-1 and the pre-TCR complex is co-ordinately regulated during the alpha beta lineage thymocyte development.

Animals↗
PubMed1999

Detection of human papilloma virus type 56 in extragenital Bowen's disease.

A case of Bowen's disease arising on the medial part of the first metatarsal bone of an 81-year-old Japanese woman is described. Histopathologically, proliferation of atypical cells was found throughout the epidermis. Electronmicroscopy revealed virus particles 40-50 nm in diameter in the nuclei of tumour cells at the granular cells just on or below the horny layer. Positive bands were obtained by polymerase chain reaction using a consensus primer of human papilloma virus L1 portion. Sequencing analysis of the amplified DNA revealed the same base sequences and homology as human papilloma virus 56. To the best of our knowledge, this case is the first report in which human papilloma virus 56 was found in a case of extragenital Bowen's disease. We consider it important to understand that human papilloma virus 56, often found in cervical lesions, can be detected in extragenital Bowen's diseases.

Aged↗
PubMed1999

Phosphate as a limiting factor for the cell division of tobacco BY-2 cells.

The re-addition of phosphate to tobacco BY-2 cells deprived of phosphate for 3 d induced cells to semi-synchronously re-enter the cell cycle from a static state. Though the addition of auxin to auxin-starved tobacco BY-2 cells also induced cell division (Ishida et al. 1993), some major differences were observed between these two systems. BY-2 cells lost the ability to re-enter the cell cycle after prolonged periods of auxin deprivation, but in contrast retained this ability after longer periods in the absence of phosphate. By differential cDNA screening we identified a phosphate-induced gene phi-1. phi-1 was rapidly induced by the addition of phosphate with transcript levels starting to decrease by the start of DNA synthesis. phi-1 does not share any significant homology with any gene with known functions over its full length. However, the N-terminus shared some homology with plasma membrane ATPases suggesting that it may be involved in some process of phosphorylation. Immunolocalization of the phi-1 gene product revealed that it rapidly accumulated in the cytoplasm prior to the start of plastid and nuclear DNA synthesis. These results are discussed in relation to the role of phosphate in inducing plant cell division.

Amino Acid Sequence↗