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Y Ishikawa

Publications and source records attributed to Y Ishikawa.

At least 91 records · Page 5Linked to original sources
PubMed2001

Expression of renin-angiotensin system genes in immature and mature dendritic cells identified using human cDNA microarray.

Using a cDNA glass microarray, the expression of 1081 genes in immature and mature dendritic cells (DCs) of two different individuals has been studied. The upregulation of mRNA transcripts of genes encoding the transcription factor ZFM1, Mos proto-oncogene serine/threonine-protein kinase, B-cell-specific transcription factor, preB-cell growth stimulating factor, ets translocation variant 6, and epidermal growth-factor-like CRIPTO was for the first time detected in DCs. Using semiquantitative RT-PCR analysis the upregulation of the transforming growth factor-alpha, integrin alpha 6 and ZFM 1 transcription factor in mature DCs was confirmed in samples from four different individuals. On the other hand, the downregulation of renin-binding protein transcript was detected in mature DCs using a cDNA microarray. For the first time, the expression of renin-angiotensin system genes was evaluated during maturation of DCs in samples from four donors by semiquantitative RT-PCR. A possible role of the renin-angiotensin system in DCs is discussed.

Antigens, CD↗
PubMed2001

Expression, function, and clinical implications of the estrogen receptor beta in human lung cancers.

The higher frequency of human lung adenocarcinoma in females than in males, strongly suggests the involvement of gender dependent factors in the etiology of this disease. This is the first investigation of estrogen receptor (ER) beta in human lung. Immunohistochemical staining revealed ERbeta expression in normal lung and in atypical adenomatous hyperplasia (AAH), considered as a precancerous lesion for adenocarcinomas. Adenocarcinomas showed significantly higher expression of ERbeta than squamous cell carcinomas. On the contrary, ERalpha expression was not detected in all cases. The functional integrity of ERbeta such as the binding ability to estrogen responsive element (ERE) and transcriptional activity was confirmed using a human lung cancer cell line, RERF-LC-OK. Colony formation of this cell was significantly reduced in the presence of pure antiestrogen. We conclude that ERbeta, but not ERalpha, is present in lung tissues with an important physiological function in normal lung. Furthermore, ERbeta may play a role in growth and development of adenocarcinomas.

Adenocarcinoma↗
PubMed2001

Dipyrimidine-copper(II) dinitrate complexes showing magnetic interactions.

Crystals of Cu(II)(NO(3))(2)(pm)(3) (1), and two crystalline forms of Cu(II)(NO(3))(2)(H(2)O)(2)(pm)(2), (2) and (3), showed ferromagnetic, antiferromagnetic and paramagnetic interactions at extremely low temperatures, respectively. Crystal structure analyses revealed that the complexes were catena-dinitrato[mu-pyrimidine-kappaN(1):kappaN(3)]-(pyrimidine-N(1))copper(II), [Cu(NO(3))(2)(pm)(2)](n), catena-diaquadinitrato[mu-pyrimidine-kappaN(1):kappaN(3)]copper(II), [Cu(NO(3))(2)(H(2)O)(2)(pm)](n), and diaquadinitratodipyrimidinecopper(II), Cu(NO(3))(2)(H(2)O)(2)(pm)(2) for (1), (2) and (3), respectively. In (1) the Cu atom is coordinated by the two nitrates and N atoms of the non-bridging pyrimidine and bridging pyrimidine to form a one-dimensional coordination polymer. The complex is a five-coordinated square pyramid and can be regarded as a pseudo-seven-coordinated complex, since other short non-bonding Cu.O contacts are observed. In the crystals of (2) the pyrimidine bridges the Cu atoms to form a one-dimensional coordination chain. On the other hand, complex (3) is not a coordination polymer. It is important to form a coordination polymer for the appearance of the magnetic interactions. Types of coordination of the bridging organic moieties should also play an important role in magnetic properties. Magnetic measurements of (1) and (2) show that they are good examples of uniform S = 1/2 ferro- and antiferromagnetic Heisenberg chains with exchange parameters 2J/kB = +1.8 and -36 K, respectively.

Journal Article↗
PubMed2001

Changes in caveolin subtype protein expression in aging rat organs.

It is now accepted that caveolin plays a key role in signal transduction by directly binding to and regulating the function of molecules involved in transmembrane signaling, such as ras, suggesting that the amount of caveolin within cells may be an important factor in determining the cellular signaling. We investigated the ontogenic changes in the protein amount of caveolin subtypes, as well as ras protein expression in various organs (the heart, lungs, and muscles) obtained from aging rats (neonates, young and old adults). Our results demonstrated that caveolin protein expression changed ontogenically in a subtype-dependent manner. In lungs, for example, caveolin-1 expression changed in an opposite manner to caveolin-3 expression, while in the heart caveolin-1 and -3 changed in parallel. Ras expression showed an ontogenic increase in lungs and a decrease in muscles, which were both parallel to caveolin-1 expression. Our results suggest that the regulation of transmembrane signaling by caveolin may differ among developmental stages and caveolin subtypes.

Aging↗
PubMed2001

IL-6 up-regulates CNTF mRNA expression and enhances neurite regeneration.

Interleukin-6 (IL-6) is a neurotrophic cytokine, however, its direct effect on nerve regeneration has not been well characterized. We therefore examined the effect of IL-6 on neurite regeneration using the rat dorsal root ganglion. IL-6 significantly enhanced neurite regeneration from transected nerve terminals. We also examined the mRNA expression of IL-6 family cytokines and their receptors during the regeneration. The mRNA expressions of IL-6, IL-6 receptor, leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF) receptor alpha, and LIF receptor beta showed no significant differences by the addition of IL-6. In contrast, IL-6 enhanced the mRNA expression of gp130 and CNTF. In addition, CNTF significantly increased neurite regeneration when added exogenously. Our data suggest that IL-6 enhanced regeneration via up-regulating CNTF expression.

Animals↗
PubMed2001

Biological characterization and optical imaging of brain-derived neurotrophic factor-green fluorescent protein suggest an activity-dependent local release of brain-derived neurotrophic factor in neurites of cultured hippocampal neurons.

To visualize the release dynamics of the brain-derived neurotrophic factor (BDNF) involved in neural plasticity, we constructed a plasmid encoding green fluorescent protein (GFP) fused with BDNF. First, several biological studies confirmed that this fusion protein (BDNF-GFP) mimics the biological functions and the release kinetics of unfused (native) BDNF. Second, when BDNF-GFP was expressed in cultured hippocampal neurons, we observed that this protein formed striking clusters in the neurites of mature neurons and colocalized with the PSD-95 immunoreactivity. Such a clustered BDNF-GFP rapidly disappeared in response to depolarization with KCl, as revealed by confocal microscopic studies. These data suggest that BDNF is locally and rapidly released at synaptic sites in an activity-dependent manner. Optical studies using BDNF-GFP may provide important evidence regarding the participation of BDNF in synaptic plasticity.

Animals↗
PubMed2001

Characterization of the stromal protease(s) degrading the cross-linked products of the D1 protein generated by photoinhibition of photosystem II.

When photosystem (PS) II-enriched membranes are exposed to strong light, cross-linking of the intrinsic D1 protein with the surrounding polypeptides and degradation of the D1 protein take place. The cross-linking of the D1 protein with the alpha-subunit of cytochrome b(559) is suggested to be an early event of photoinduced damage to the D1 protein (Barbato et al., FEBS Lett. 309 (1992) 165-169). The relationship between the cross-linking and the degradation of the D1 protein, however, is not yet clear. In the present study, we show that the addition of stromal extract from chloroplasts degrades the 41 kDa cross-linked product of D1/cytochrome b(559) alpha-subunit and enhances the degradation of the D1 protein. Incubation of the preilluminated PS II-enriched membranes with the stromal extract at 25 degrees C causes the degradation of the cross-linked product by more than 70%. The activity of the stromal extract showed a pH optimum at 8.0, and was enhanced by the addition of ATP or GTP. Consistent with the nucleotide effect, this stromal activity was eliminated by the preincubation of the stromal extract with apyrase, which hydrolyzes nucleotides. Also, the stromal activity was nearly fully inhibited by a serine-type protease inhibitor, 3,4-dichloroisocoumarin, which suggests participation of a serine-type protease(s).

Apyrase↗
PubMed2001

The effect of myocardial bridging of the coronary artery on vasoactive agents and atherosclerosis localization.

The relationship between alterations in the immunohistochemical expression of three vasoactive agents [endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), and angiotensin-converting enzyme (ACE)] and the occurrence human atherosclerosis was investigated in relation to the myocardial bridge (MB) of the left anterior descending coronary artery (LAD), an anatomical site that experiences increased shear stress. Five millimetre cross-sections of LADs with MB from 22 autopsied cases were taken from the left coronary ostium to the cardiac apex and were immunohistochemically stained with antibodies against eNOS, ET-1, and ACE. The extent of atherosclerosis in each section was calculated using the atherosclerosis ratio (intimal cross-sectional area/medial cross-sectional area) determined by histomorphometry. The results were analysed according to their anatomical location relative to the MB, either proximal, beneath, or distal. The extent of atherosclerosis was significantly lower beneath the MB, compared with proximal and distal segments. The expression of eNOS, ET-1, and ACE was also significantly lower beneath the MB. The expression of these agents correlated significantly with the extent of atherosclerosis. Because nitric oxide, after its production by eNOS, is believed to be degraded by superoxide radicals, the effect of eNOS expression on atherosclerosis remains controversial. However, the present findings clearly indicate that the expression of ET-1 and ACE is directly related to the development of human coronary atherosclerosis in vivo through shear stress.

Adult↗
PubMed2001

Relationship between thallium-201 kinetics and proliferative activity assessed by monoclonal antibody MIB-1 in brain tumours.

To clarify the relationship between thallium-201 chloride kinetics and proliferative activity in brain tumours. a single-photon emission tomographic (SPET) study was performed and the results correlated with monoclonal antibody MIB-1 staining of the tumour tissue. 201T1 SPET was performed 10 min (early scan) and 2 h (delayed scan) after intravenous administration of 201TI (111 MBq) in 34 intra-axial tumours including 24 malignant tumours, and in 27 extra-axial tumours including one malignant tumour. Tumour 201T1 kinetic parameters [early and delayed uptake ratios (ER and DR, respectively), retention index (RI), and the ratio of tumour delayed activity to early activity (Td/Te)] were compared with tumour tissue MIB-1 labelling indices (MIB-1 LI) representative of tumour cell proliferative activity. In the intra-axial tumours, ER and DR and MIB-1 LI were significantly higher in the malignant tumours than in the benign tumours. ER and DR were significantly correlated with MIB-1 LI (P<0.01 and P<0.05, respectively), but RI and Td/Te were not. In the extra-axial benign tumours, ER was as high as that in the intra-axial malignant tumours, while MIB-1 LI was equal to that in the intra-axial benign tumours. There were no significant correlations between any 201T1 kinetic parameters and MIB-1 LI. This study indicates that 201T1 ER may be the most reliable parameter for predicting the proliferative activity of intra-axial tumours.

Adolescent↗
PubMed2001

Two mutations of the Gsalpha gene in two Japanese patients with sporadic pseudohypoparathyroidism type Ia.

Pseudohypoparathyroidism Ia (PHP-Ia), is an inherited disease with clinical hypoparathyroidism caused by parathyroid hormone resistance (PTH), and shows the phenotype of Albright hereditary osteodystrophy (AHO), including short stature, obesity, round face, brachydactyly, and subcutaneous ossification. This disease is caused by mutation that inactivates the alpha-subunit of Gs, the stimulatory regulator of adenylyl cyclase. Here, a novel frameshift mutation (delG at codon 88) in exon 4, and a missense mutation (R231H) in exon 9 of the Gsalpha gene were identified in two Japanese patients with sporadic PHP-Ia. Deletion of a G in exon 4 at codon 88 in the first patient produced a premature stop codon, resulting in the truncated protein. The second patient had a previously reported R231H mutation. Because this amino acid is located in a region, switch 2, that is thought to interact with the betagamma subunit of Gsalpha protein, this mutation may impair Gs protein function. We report here one novel Gsalpha mutation, and note that mutations in Japanese patients with PHP-Ia are probably heterogeneous.

Adult↗
PubMed2001

Accumulation of molecules involved in alpha1-adrenergic signal within caveolae: caveolin expression and the development of cardiac hypertrophy.

OBJECTIVE: Caveolin, a major protein component of caveolae, is now considered to be an inhibitor of cellular growth and proliferation. In this study, we examined the localization of the molecules involved in alpha1-adrenergic receptor signal relative to that of caveolin in the heart and the changes in caveolin expression during the development of hypertrophy in SHR. METHODS: We purified the caveolar protein fractions from rat cardiac tissues, H9C2 cells, and rat vascular smooth muscle cells. Using radioligand receptor binding assay and immunoblot analysis, we examined the distribution and the amount of alpha1-AR and caveolin. RESULTS: Caveolin-3, the alpha1-adrenergic receptor, Gq and PLC-beta subtypes (PLC-beta1, -beta3) were found exclusively in the caveolar fraction in the above tissues. Caveolin-3 were co-immunoprecipitated with alpha1-adrenergic receptor and Gq from the cardiac tissues. The amount of caveolin subtypes expression (caveolin-1 and -3) and the amount of the alpha1-adrenergic receptor were examined in the hearts of SHR and age-matched WKY (4- and 24-weeks-old). The amount of caveolin-3 expression was significantly smaller in SHR at 24-weeks-old than that in SHR at 4-weeks-old and that in WKY at 24-weeks-old. CONCLUSIONS: The molecules involved in alpha1-adrenergic signaling are confined to the same microdomain as caveolin. A decrease in caveolin-3 expression may play a role in the development of cardiac hypertrophy in SHR, presumably through de-regulating the inhibition of growth signal in the hearts of SHR in the hypertrophic stage.

Analysis of Variance↗