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T Nakajima

Publications and source records attributed to T Nakajima.

At least 163 records · Page 9Linked to original sources
PubMed2001

The binocular accommodative response in uncorrected ametropia.

PURPOSE: To measure the changes in astigmatism and in the degree of anisometropia when ametropes respond to accommodative stimulation. METHODS: The accommodative responses of ametropes were binocularly measured with an improved photorefractometer (PR-1100), which objectively measured binocular refraction in all meridians simultaneously, when a visual fixation target was shown in natural space at 5 and 0.5 m. RESULTS: (1) Changes of astigmatism and anisometropia occur during binocular accommodation. (2) Changes of astigmatism mainly result from lag of accommodation in the horizontal meridian. (3) Changes of anisometropia result from the effort to focus. (4) The interaction of both eyes is suggested as the cause of the changes of astigmatism and anisometropia with accommodation. (5) In the majority of strong anisometropes (nonoverlapping group in this paper), the magnitude of anisometropia decreases (approaching isometropia) with accommodation. CONCLUSION: Changes in astigmatism and anisometropia can occur during accommodation, and these interactions of both eyes with accommodation may contribute to the development and maintenance of binocular function.

Accommodation, Ocular↗
PubMed2001

Aberrant expression of pRb, p16, p14ARF, MDM2, p21 and p53 in squamous cell carcinomas of lung.

Expression of cell cycle regulatory proteins in both the RB and p53 pathways was investigated in 50 cases of squamous cell carcinoma (SCC) of the lung using immunohistochemical techniques. Abnormality of pRb and p16 expression was seen at the frequencies of 16% and 78%, respectively, and appeared to be in a reciprocal relationship. On the other hand, strong and diffuse p53 immunoreactivity was seen in 60% of SCCs. MDM2 and p14ARF expressions were each observed in about half of the cases of SCC and were not significantly associated with strong p53 immunoreactivity. Statistical analysis revealed that p14ARF expression was significantly correlated with both p16 and MDM2 expression. Moreover, strong p53 expression was not correlated with the expression of p21. In comparing clinicopathological status with the immunohistochemical results, lack of p16 immunoreactivity was observed in the elderly group (over 65 years) as compared with the younger group (less than 65 years). Strong p53 expression was frequently observed in higher stages of SCC, with the developing tumor located in the central field of the lung. Similarly, the frequency of p14ARF expression was high in centrally developed SCC, but low in SCC developed in the periphery. These results suggest that disruption of the RB and p53 pathways is a frequent event in SCC, and that abnormal expression of p16 and p53 plays a more critical role than that of pRB, p14ARF and MDM2 in the development of SCC of the lung.

Age Factors↗
PubMed2001

Dual roles of RNA helicase A in CREB-dependent transcription.

RNA helicase A (RHA) is a member of an ATPase/DNA and RNA helicase family and is a homologue of Drosophila maleless protein (MLE), which regulates X-linked gene expression. RHA is also a component of holo-RNA polymerase II (Pol II) complexes and recruits Pol II to the CREB binding protein (CBP). The ATPase and/or helicase activity of RHA is required for CREB-dependent transcription. To further understand the role of RHA on gene expression, we have identified a 50-amino-acid transactivation domain that interacts with Pol II and termed it the minimal transactivation domain (MTAD). The protein sequence of this region contains six hydrophobic residues and is unique to RHA homologues and well conserved. A mutant with this region deleted from full-length RHA decreased transcriptional activity in CREB-dependent transcription. In addition, mutational analyses revealed that several tryptophan residues in MTAD are important for the interaction with Pol II and transactivation. These mutants had ATP binding and ATPase activities comparable to those of wild-type RHA. A mutant lacking ATP binding activity was still able to interact with Pol II. In CREB-dependent transcription, the transcriptional activity of each of these mutants was less than that of wild-type RHA. The activity of the double mutant lacking both functions was significantly lower than that of each mutant alone, and the double mutant had a dominant negative effect. These results suggest that RHA could independently regulate CREB-dependent transcription either through recruitment of Pol II or by ATP-dependent mechanisms.

Adenosine Triphosphatases↗
PubMed2001

Use of human recombinant DNase I expressed in COS-7 cells as an immunogen to produce a specific anti-DNase I antibody.

To obtain human deoxyribonuclease I (DNase I) as an immunogen, we have developed a procedure that is more useful and effective than the conventional procedure, which uses human urine as a starting material. In the new procedure, we culture COS-7 cells transfected with expression vector carrying human DNase I cDNA, and then purify the enzyme from the culture medium. The enzyme can be easily isolated to apparent homogeneity by passage through only three chromatography columns. The rabbit antiserum that we used against the recombinant DNase I was not inferior to that used against DNase I from human urine, in terms of both its ability to discriminate DNase I phenotypes and its ability to neutralize enzyme activity. Therefore, our procedure may be useful for producing an antibody specific for human DNase I.

Animals↗
PubMed2001

Regulation of surface FcepsilonRI expression on human eosinophils by IL-4 and IgE.

BACKGROUND: Recent studies have demonstrated that eosinophils from allergic patients express low levels of FcepsilonRI on their surface, but the regulatory mechanisms of eosinophil surface FcepsilonRI expression are not fully understood. We investigated whether IL-4 and IgE, which are reported to regulate surface FcepsilonRI expression on human mast cells, are able to affect surface FcepsilonRI expression in normal human eosinophils. METHODS: Eosinophils purified from peripheral blood were cultured with IL-5 and with or without IL-4 and/or IgE, and surface FcepsilonRI expression was analyzed by flow cytometry using an anti-FcepsilonRI mAb, CRA-1. RESULTS: Apparent FcepsilonRI expression (approximately 1% of mast cell FcepsilonRI levels) was observed in eosinophils cultured with both IL-4 and IgE. A combination of IL-4 (>or=1 ng/ml) and IgE (>or= 0.5 microg/ml) was necessary for the maximal induction of surface FcepsilonRI expression. In the presence of IL-4 and IgE, eosinophils cultured for 2 days demonstrated low but statistically significant levels of surface FcepsilonRI, which reached a plateau after 7 days of culture. However, cross-linkage of surface FcepsilonRI molecules by CRA-1 or anti-IgE did not induce any eosinophil activation. CONCLUSIONS: IL-4 and IgE can affect the levels of surface FcepsilonRI on normal human eosinophils. FcepsilonRI expression on eosinophils may be regulated by a mechanism similar to that in mast cells.

Cells, Cultured↗
PubMed2001

Human mast cell transcriptome project.

After draft reading of the human genome sequence, systemic analysis of the transcriptome (the whole transcripts present in a cell) is progressing especially in commonly available cell types. Until recently, human mast cells were not commonly available. We have succeeded to generate a substantial number of human mast cells from umbilical cord blood and from adult peripheral blood progenitors. Then, we have examined messenger RNA selectively transcribed in these mast cells using high-density oligonucleotide probe arrays. Many unexpected but important transcripts were selectively expressed in human mast cells. We discuss the results obtained from transcriptome screening by introducing our data regarding mast-cell-specific genes.

Blood Cells↗
PubMed2001

Identification of N-terminal autodigestion target site in subtilisin ALP I.

Autodigestion of subtilisin ALP I (ALP I), secreted from the alkalophilic Bacillus sp. NKS-21 and its predicted amino acid sequence having about 60% identity with other alkaline subtilisins, was examined under alkaline conditions. At the alkaline pH of 12, ALP I was rapidly degraded, and almost no breakdown products were detectable. However, by incubating ALP I at 5 degrees C for an extended time, a couple of specific peptides (26.7 kDa and 25.6 kDa) were accumulated. Each of them was purified and amino acid sequences of these fragments were found. Both peptides appeared to start at Gly-19 of the mature sequence of ALP I.

Amino Acid Sequence↗
PubMed2001

Characterization of recombinant yeast exo-beta-1,3-glucanase (Exg 1p) expressed in Escherichia coli cells.

Yeast exo-beta-1,3-glucanase gene (EXG1) was expressed in Escherichia coli and the recombinant enzyme (Exg1p) was characterized. The recombinant Exglp had an apparent molecular mass of 45 kDa by SDS-PAGE and the enzyme has a broad specificity for beta-1,3-linkages as well as beta-1,6-linkages, and also for other beta-glucosidic linked substrates, such as cellobiose and pNPG. Kinetic analyses indicate that the enzyme prefers small substrates such as laminaribiose, gentiobiose, and pNPG rather than polysaccharide substrates, such as laminaran or pustulan. With a high concentration of laminaribiose, the enzyme catalyzed transglucosidation forming laminarioligosaccharides. The enzyme was strongly inhibited with high concentrations of laminaran.

Culture Media↗
PubMed2001

Enhancement of endothelial nitric oxide production by chenodeoxycholic acids in patients with hepatobiliary diseases.

The purpose of this study was to clarify whether physiological concentrations of bile acids could affect endothelial nitric oxide production. We investigated the relationships between clinical concentrations of individual bile acids observed in patients with hepatobiliary diseases and endothelial nitric oxide production induced by each bile acid. Fifteen serum bile acids were measured using high-performance liquid chromatography combined with enzymatic fluorometry in 8 patients with liver cirrhosis, obstructive jaundice, and 8 healthy subjects. The effects of individual bile acids on nitric oxide production were examined in human umbilical endothelial cells by measuring the concentration of NO2- in the cultured medium. NO release in the blood was also determined by measuring the NO2-/NO3- concentration in these patients. In patients with hepatobiliary diseases, the plasma concentrations of chenodeoxycholic acid, ursodeoxycholic acid and cholic acid (free acid, taurine and glycine conjugates) were markedly elevated. Incubation of cells with chenodeoxycholic acid and deoxycholic acid (free acid, taurine and glycine conjugates) enhanced NO2- production in a concentration-dependent manner, while cholic acid (free and its conjugates) did not. The effects of individual bile acids on nitric oxide production were additive. Patients with liver cirrhosis and obstructive jaundice had higher plasma levels of NO2-/NO3- levels than the control subjects. These results suggest that increased plasma concentrations of chenodeoxycholic acid (free, taurine and glycine conjugates) in patients with hepatobiliary diseases may induce endothelial nitric oxide production. Thus, nitric oxide production induced by bile acids may be involved in the pathogenesis of circulatory abnormalities in patients with liver diseases.

Aged↗
PubMed2001

Familial adult onset primary alveolar hypoventilation syndrome.

A 41-year-old man fell into type II respiratory failure after catching a cold, and became dependent on a respirator. Chest radiography showed no abnormalities and the hyperventilation test showed improved arterial blood gas findings. His sleep study showed marked nocturnal desaturation due to hypopnea and apnea with a decrease of thoracic and abdominal movement during sleep. Therefore, we diagnosed him as primary alveolar hypoventilation syndrome (PAH). Seven years previously, his 2-year elder sister had suffered from similar respiratory failure during her second pregnancy and had been diagnosed as PAH. While myopathy was suspected in both cases, attenuation of muscle strength was slight and it appeared not to be the main cause of alveolar hypoventilation. Since medication was not effective in each case, they underwent non-invasive positive pressure ventilation (NIPPV). While sustained mild hypercapnia remained during the daytime, it improved their respiratory failure. To our knowledge, this is the first study of familial adult onset PAH.

Adult↗
PubMed2001

NFkappaB2 (p52) promoter activation via Notch signaling pathway in rheumatoid synoviocytes.

Rheumatoid synoviocytes produce inflammatory cytokines and exhibit strong proliferation activity, which cause severe cartilage destruction in the joints. Previously, we reported that NFkappaB, a transcriptional factor that activated by mitogenic signals, was activated in rheumatoid synoviocytes. In addition, we revealed that Notch-1, the transcriptional factor that is involved in the developmental stages, was abnormally activated in rheumatoid synoviocytes. In this study, as one of the roles of Notch-1 for the chronic inflammation in RA, we examined its implication to NFkappaB2 activation in rheumatoid synoviocytes. Western blotting analysis showed that NFkappaB2 expression was elevated in rheumatoid synoviocytes compared with patients with osteoarthritis studied as control. We then analyzed NFkappaB2 binding activity to the promoter and revealed that kappaB binding complexes to the NFkappaB2 promoter was elevated in rheumatoid synoviocytes. We analyzed implication of Notch-1 signaling pathway on NFkappaB2 activation, and found that Notch-1 made a complex with recombination binding protein Jkappa (RBPJkappa), a repressor for NFkappaB2 promoter, and blocked binding of RBPJkappa to the promoter. These results indicated that as one of the mechanisms for nuclear translocated Notch-1, complex formation with RBPJkappa induces blocking of the NFkappaB2 promoter suppression, which might cause NFkappaB2 promoter activation.

Arthritis, Rheumatoid↗
PubMed2001

Effects of interaction between parvovirus minute virus of mice NS1 and coactivator CBP on NS1- and p53-transactivation.

The non-structural protein NS1, encoded by the parvovirus minute virus of mice (MVM), is a potent regulator of viral gene expression in addition to prominent roles in viral replication and cytopathic effects associated with parvoviral infection. Although NS1 involves the modulation of viral and cellular transcription, the primary activation mechanism of MVM NS1 remains unclear. In the present study, we show here that the coactivator CREB binding protein, CBP, could potentiate NS1-mediated transcription as measured on the P38 promoter, which drives expression of the MVM capsid genes. NS1 bound to the two related cysteine-histidine-rich regions of CBP, referred to as C/H1 and C/H3, the former of which has an antagonistic function to CBP upon the NS1-transactivation. Furthermore, NS1 inhibited the synergistic transactivation by CBP and p53. These findings suggested that CBP as a transcriptional coactivator is required for NS1-mediated viral and cellular transcription in parvovirus-infected cells, resulting in cell proliferation and differentiation to achieve its lytic cycle.

3T3 Cells↗
PubMed2001

Dimerization of small GTPase Rab5.

Rab proteins are small GTPases, localized to distinct cellular compartments, regulating specific steps of intracellular membrane trafficking. One member of the Rab family, Rab5, consists of three isoforms, Rab5a, Rab5b, and Rab5c, which have been shown to play an important role in early events of endocytosis. Using the yeast two-hybrid system, we have identified several cytosolic proteins that interact with the Rab5b Q79L (decreasing intrinsic and GTPase-activating protein-stimulated GTPase activities). Surprisingly, most positive clones were Rab5b or Rab5c, indicating that Rab5 could dimerize among extra-isoforms in the yeast two-hybrid system. In vitro and in vivo chemical cross-linking assays demonstrated that lipid-unmodified wild-type Rab5b purified from Escherichia coli, wild-type Rab5b, or a dominant active form Rab5b Q79L expressed in human 293T cells dimerized. Furthermore, the same assays using a Rab5b R81A substitution mutant showed that the Arg81 in the Switch II region [the second GTP/GDP binding motif (residues 74-93)] was essential for Rab5b dimerization. These results suggest that Rab5 isoforms can be dimerized depending upon the GTP-bound conformation, but independent upon a lipid modification.

Amino Acid Sequence↗
PubMed2001

Expression of bone formation-related molecules in a newly established protein-independent osteosarcoma.

Protein-independent cells are useful for analysis of proteins that are produced by the cells themselves without any consideration of exogenous proteins. This experimental protein-independent tumor system provides new biology of the autonomous nature of neoplastic cells during their evolution. We established a Dunn protein-free osteosarcoma (DPF) cell line, which was derived from parental fetal calf serum (FCS)-dependent murine Dunn osteosarcoma (DOS) cells. The DPF cells grew in a chemically defined protein-free medium at the high seeding density of 1x10(4) cells/well of a 96-well-plate with a similar doubling time to that of cells growing in the presence of FCS, while the cells did not grow at a density lower than 1x10(3)/well. Furthermore, addition of conditioned medium stimulated the growth in a dose-dependent manner. In contrast, DOS did not grow in the protein-free condition at all. Morphological examination revealed that DPF cells exhibited a more round shape than DOS cells. RT-PCR analysis exhibited the augmentation of the RNA message of bone morphogenetic protein-4 (BMP-4) and osteocalcin in DPF cells. Enhanced expression of BMP-4 protein was also demonstrated by immunoblot analysis. Furthermore, alkaline phosphatase (ALP) activity was higher in DPF cells, indicating that bone-formation related molecules may be overexpressed in protein-independent osteosarcoma cells. These results suggest that putative growth factors may play a role in the DPF cell growth in an autocrine fashion, and the acquisition of autonomous growth independent of exogenous proteins may be coupled to the osteogenic differentiation.

Alkaline Phosphatase↗
PubMed2001

[A case report of allergic fungal sinusitis caused by Penicillium sp. and Cladosporium sp].

We report a case of allergic fungal sinusitis (AFS) caused by Penicillium sp. and Cladosporium sp. in a 57-year-old man satisfying the following diagnostic criteria: (1) chronic rhinosinusitis revealed by computed tomographic scan, (2) Japanese cedar pollinosis for 3 years, (3) positivity for Penicillium sp. and Cladosporium sp. by a skin test, (4) increased immunoglobulin E (IgE) specific to these fungi, (5) increased total IgE, (6) nasal polyps with severe eosinophilic invasion, (7) allergic mucin revealed by histopathological examination, (8) fungal hyphae revealed by histopathological examination and (9) detection of Penicillium sp. and Cladosporium sp. revealed by fungi culture. The patient was treated by endoscopic sinus surgery. Four weeks after surgery, nasal polyps recurred, but his condition was improved by oral administration of steroids and nebulizer treatment with steroids and fluconazole. Total IgE, specific IgE and eosinophil count in the peripheral blood decreased, apparently reflecting this improvement. After obtaining the patient's consent, we conducted an allergen provocation test, which is as highly diagnostic as a skin test, to test for an antigen causing type I hypersensitivity. The immediate phase response was positive, indicating that type I hypersensitivity intermediated by IgE was involved in AFS.

Cladosporium↗
PubMed2001

[Possible pathogenesis of rheumatoid arthritis].

Rheumatoid fibroblast-like synoviocytes characteristically proliferate in an anchorage-independent manner, and are deeply implicated in cartilage destruction. Our previous results showed that rheumatoid synoviocytes expressed Fas ligand and were induced apoptosis by anti-Fas antibody treatment. In addition, several transcriptional factors, such as NF kappa B and AP-1 significantly activated in rheumatoid synoviocytes. We are now clarifying the pathogenesis of RA with the method, yeast two-hybrid system as 'post genome' strategy. We recently found that several factors that related with cell differentiation highly expressed in rheumatoid synoviocytes. In this report we discuss possible pathogenesis of RA based on our recent data and application to the therapy tool against RA.

Apoptosis↗