Search PubMed⌕ Search

Biomedical subjects

Y Inagaki

Publications and source records attributed to Y Inagaki.

At least 37 records · Page 2Linked to original sources
PubMed2002

Dilazep hydrochloride, an antiplatelet drug, prevents progression of diabetic nephropathy in Otsuka Long-Evans Tokushima fatty rats.

Diabetic nephropathy is a leading cause of end-stage renal disease in industrialized countries. Although the mechanisms for the development and progression of diabetic nephropathy are not fully understood, platelet activation may participate in its pathogenesis by promoting microthrombus formation. In this study, we investigated the effects of dilazep hydrochloride, an antiplatelet agent, on the development and progression of diabetic nephropathy in Otsuka Long-Evans Tokushima fatty (OLETF) rats, a type 2 diabetes mellitus animal model. Administration of dilazep hydrochloride significantly reduced the increase of urinary protein excretions and N-acetyl-beta-D-glucosaminidase (NAG) activity in OLETF rats. Furthermore, dilazep hydrochloride treatment prevented glomerulosclerosis and tubular atrophy and reduced positive staining for type IV collagen in the glomeruli of diabetic rats. These results indicate that platelet activation plays a dominant role in the development and progression of diabetic nephropathy. Our study suggests that dilazep hydrochloride is a valuable new drug for the treatment of diabetic patients with nephropathy.

Acetylglucosaminidase↗
PubMed2002

Up-regulation of vascular endothelial growth factor and down-regulation of pigment epithelium-derived factor messenger ribonucleic acid levels in leptin-exposed cultured retinal pericytes.

Leptin, a circulating hormone secreted mainly from adipose tissues, is involved in the control of body weight. Recently, leptin was found to be an angiogenic factor and its vitreous levels were shown to be elevated in patients with angiogenic eye diseases such as proliferative diabetic retinopathy. However, the role of leptin in diabetic retinopathy is not fully understood. Since pericyte loss and dysfunction have been considered to be one of the characteristic changes of the early phases of diabetic retinopathy, we investigated the effects of leptin on the growth and function of bovine cultured retinal pericytes. Although it did not affect cell growth, leptin significantly up-regulated pericyte messenger ribonucleic acid levels of an endogenous angiogenic stimulator, vascular endothelial growth factor (VEGF). Leptin was also found to significantly inhibit gene expression of pigment epithelium-derived factor (PEDF), the most potent angiogenesis inhibitor in the mammalian eye, in pericytes. The present study suggests that leptin might elicit angiogenesis through VEGF induction as well as PEDF suppression in pericytes and could thus be involved in the development and progression of diabetic retinopathy, especially in obese insulin-resistant patients.

Animals↗
PubMed2002

Pigment epithelium-derived factor Met72Thr polymorphism in patients with diabetic microangiopathy.

Pigment epithelium-derived factor (PEDF) has recently been shown to be the most potent inhibitor of angiogenesis in the mammalian eye. We, along with others, have very recently found that loss of PEDF is involved in the development and progression of diabetic retinopathy. However, there are no studies on the allelic effects of PEDF gene polymorphism in diabetic retinopathy. In this study, we investigated whether a functional amino acid change, a methionine to threonine polymorphism (Met72Thr polymorphism) of the PEDF gene, is associated with microangiopathy in 143 patients with diabetes. We found that there were no significant associations between PEDF Met72Thr gene polymorphism and diabetic microangiopathy. These observations suggest that these genetic variants might not be involved in the mechanism of diabetic microangiopathy in patients with diabetes.

Adult↗
PubMed2001

Genomic organization and transcription units of the human acyl-CoA synthetase 3 gene.

Acyl-CoA synthetases (ACSs) play an essential role in fatty acid metabolism. ACS3 is an arachidonate-preferring enzyme expressed in a wide range of human tissues including brain, heart, placenta, prostate, skeletal muscle, testis and thymus. As an initial step to understanding the transcriptional regulation of the human ACS3 gene, we analyzed the genomic organization and transcription units of the human ACS3 gene. Sequence analysis of genomic clones demonstrates that the human ACS3 gene spans at least 80.6 kb and contains 17 exons. The human ACS3 gene was mapped between the sequence-tagged site markers D2S360 and WI-21901. Sequence inspection of the 5'-flanking region revealed potential DNA elements including CCAAT, AP-1, Oct-1, GATAs, SRY, CdxA, Nkx-2.5, c-Myb, HSF2, NF-AT, AP-2, NF-Y, and p300. A minimal promoter region required for the expression of the human ACS3 gene in melanoma G361 cells was determined.

5' Flanking Region↗
PubMed2001

Exon/intron organization and transcription units of the human acyl-CoA synthetase 4 gene.

Acyl-CoA synthetase 4 (ACS4) is an arachidonate-preferring isozyme of ACS family predominantly expressed in steroidogenic tissues. Isolation and characterization of genomic clones encoding human ACS4 revealed that the genomic organization of the gene. The human ACS4 gene spans approximately 90 kb and consists of 16 exons. Sequence inspection of the 5'-flanking region revealed potential DNA elements including GATAs, p300, AP-4, SRY, CREB and MyoD. A minimal promoter region required for the expression of ACS4 in HeLa S3 cells was determined. The human ACS4 gene was mapped between the STS markers, WI-17685 and CHLC.GATA81B07 on Xq22-23 region.

Amino Acid Sequence↗
PubMed2001

Critical contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to apoptosis of human CD4+ T cells in HIV-1-infected hu-PBL-NOD-SCID mice.

Apoptosis is a key for CD4+ T cell destruction in HIV-1-infected patients. In this study, human peripheral blood lymphocyte (PBL)-transplanted nonobese diabetic (NOD)-severe combined immunodeficient (SCID) (hu-PBL-NOD-SCID) mice were used to examine in vivo apoptosis after HIV-1 infection. As the hu-PBL-NOD-SCID mouse model allowed us to see extensive infection with HIV-1 and to analyze apoptosis in human cells in combination with immunohistological methods, we were able to quantify the number of apoptotic cells with HIV-1 infection. As demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), massive apoptosis was predominantly observed in virus-uninfected CD4+ T cells in the spleens of HIV-1-infected mice. A combination of TUNEL and immunostaining for death-inducing tumor necrosis factor (TNF) family molecules indicated that the apoptotic cells were frequently found in conjugation with TNF-related apoptosis-inducing ligand (TRAIL)-expressing CD3+CD4+ human T cells. Administration of a neutralizing anti-TRAIL mAb in HIV-1-infected mice markedly inhibited the development of CD4+ T cell apoptosis. These results suggest that a large number of HIV-1-uninfected CD4+ T cells undergo TRAIL-mediated apoptosis in HIV-infected lymphoid organs.

Animals↗
PubMed2001

Class I release factors in ciliates with variant genetic codes.

In eukaryotes with the universal genetic code a single class I release factor (eRF1) most probably recognizes all stop codons (UAA, UAG and UGA) and is essential for termination of nascent peptide synthesis. It is well established that stop codons have been reassigned to amino acid codons at least three times among ciliates. The codon specificities of ciliate eRF1s must have been modified to accommodate the variant codes. In this study we have amplified, cloned and sequenced eRF1 genes of two hypotrichous ciliates, Oxytricha trifallax (UAA and UAG for Gln) and Euplotes aediculatus (UGA for Cys). We also sequenced/identified three protist and two archaeal class I RF genes to enlarge the database of eRF1/aRF1s with the universal code. Extensive comparisons between universal code eRF1s and those of Oxytricha, Euplotes, and Tetrahymena which represent three lineages that acquired variant codes independently, provide important clues to identify stop codon-binding regions in eRF1. Domain 1 in the five ciliate eRF1s, particularly the TASNIKS heptapeptide and its adjacent region, differs significantly from domain 1 in universal code eRF1s. This observation suggests that domain 1 contains the codon recognition site, but that the mechanism of eRF1 codon recognition may be more complex than proposed by Nakamura et al. or Knight and Landweber.

Amino Acid Sequence↗
PubMed2001

Interaction between GC box binding factors and Smad proteins modulates cell lineage-specific alpha 2(I) collagen gene transcription.

Type I collagen is produced predominantly in mesenchymal cells, but molecular mechanisms responsible for cell type-specific expression are virtually unknown. During fibrogenic process in the liver, activated hepatic stellate cells (HSC) are the main producers of type I collagen, whereas parenchymal hepatocytes produce little, if any, of this protein. We have previously reported that Sp1 and an interacting unknown factor(s) bind to the -313 to -255 sequence of the alpha2(I) collagen gene (COL1A2) and play essential roles for basal and TGF-beta-stimulated transcription in skin fibroblasts and HSC. Recently, Smad3 has been shown to bind to this region, and its interaction with Sp1 has been implicated in TGF-beta-elicited COL1A2 stimulation. The present study demonstrates predominant binding of Sp3 rather than Sp1 to this regulatory element in parenchymal hepatocytes. In these cells, this region did not exhibit strong enhancer activity or mediate the effect of TGF-beta. Transfection of HSC with an Sp3 expression plasmid abolished the COL1A2 response to TGF-beta, whereas overexpression of Sp1 in hepatocytes increased basal COL1A2 transcription and conferred TGF-beta responsiveness. Functional and physical interactions between Sp1 and Smad3, but not between Sp3 and Smad3, were demonstrated using the bacterial GAL4 system and immunoprecipitation-Western blot analyses. These results indicate that cell lineage-specific interactions between GC box binding factors and Smad protein(s) may account, at least in part, for differential COL1A2 transcription and TGF-beta responsiveness in HSC and parenchymal hepatocytes.

Animals↗
PubMed2001

Constitutive phosphorylation and nuclear localization of Smad3 are correlated with increased collagen gene transcription in activated hepatic stellate cells.

Hepatic stellate cells (HSC) are the main producers of type I collagen in fibrotic liver, and transforming growth factor-beta (TGF-beta) plays critical roles in stimulating collagen gene expression in the cells mainly at the level of transcription. We have previously identified an upstream sequence of alpha2(I) collagen gene (COL1A2) that is essential for its basal and TGF-beta-stimulated transcription in skin fibroblasts and HSC. We designated this region the TGF-beta-responsive element (TbRE). Recently Smad3, an intracellular mediator of TGF-beta signal transduction, has been shown to bind to the TbRE and stimulate COL1A2 transcription when overexpressed in skin fibroblasts. In the present study, we demonstrate increased transcription of COL1A2 and plasminogen activator inhibitor-1 (PAI-1) genes and low response to TGF-beta in an activated HSC clone derived from a cirrhotic liver. Western blot analyses indicated constitutive phosphorylation of Smad3 in the cells. Immunofluorescence studies revealed that, in contrast to Smad2 that translocated from the cytoplasm to the nucleus upon TGF-beta treatment, Smad3 and Smad4 were present in the nucleus irrespective of ligand stimulation. Increased COL1A2 and PAI-1 gene transcription in the cells was not affected by overexpression of inhibitory Smad7. Altogether, the results correlate abnormality in TGF-beta/Smad signaling with pathologically accelerated collagen gene transcription in activated HSC.

Animals↗
PubMed2001

Interferon-associated retinopathy in a uniform regimen of natural interferon-alpha therapy for chronic hepatitis C.

BACKGROUND/AIMS: The development of retinal lesions induced by a uniform regimen of interferon-alpha therapy for chronic hepatitis C was prospectively investigated. METHODS: Eighty-one patients received 6 mega units of natural interferon-alpha intramuscularly daily for 2 weeks and then 3 times a week for 22 weeks. The total dose of interferon-alpha administered was uniformly 478 mega units per patient. Two expert ophthalmologists prospectively examined the patients for retinal lesions before, during and after the therapy. RESULTS: Retinopathy was not found in comparison groups or any of the patients before treatment. In total 34.6% (28/81) of the patients showed cotton-wool spots or minor retinal hemorrhage, or both lesions, during therapy, but these lesions were reversed during or after interferon therapy. The occurrence rates of cotton-wool spots alone, retinal hemorrhage alone and both lesions were 13.6% (11/81), 6.2% (5/81), and 14.8% (12/81), respectively. The appearance of retinopathy did not correlate with patients' background including viral loads and response to the therapy, but was more frequently found in older patients and patients with hypertension and/or diabetes mellitus; disappearance of retinopathy was more prolonged than in patients without these complications. Almost all the lesions appeared 2-4 months after the start of the therapy, and the severity of the lesions did not differ between patients with and without hypertension and/or diabetes mellitus. CONCLUSION: Although it is not clear if interferon-associated retinopathy occurs in a dose-dependent manner, the present study shows a standard pattern of the occurrence of retinopathy in patients with chronic hepatitis C receiving a uniform dosage of natural interferon-alpha.

Age Distribution↗
PubMed2001

A prescriptive exercise program for health maintenance.

The aim of this study was to design a prescriptive exercise program for people of various age and fitness basing on the popular in Japan Radio Physical Fitness Exercise, a program based on an experimental approach. The evaluation indices used in the experiment were heart rate (HR), oxygen consumption, and electrical activity of the rectus femoris, latissimus dorsi, and trapezius muscles, which measured during various motion elements of the program performed at various rate. The results of this study enable to calculate equations for predicting HR during exercise from relative metabolic rate (RMR). The data on HR, RMR, and myoelectric potential presented in this study may be a basis for designing individual exercise programs for elderly people.

Adult↗
PubMed2001

Genes encoding the vacuolar Na+/H+ exchanger and flower coloration.

Vacuolar pH plays an important role in flower coloration: an increase in the vacuolar pH causes blueing of flower color. In the Japanese morning glory (Ipomoea nil or Pharbitis nil), a shift from reddish-purple buds to blue open flowers correlates with an increase in the vacuolar pH. We describe details of the characterization of a mutant that carries a recessive mutation in the Purple (Pr) gene encoding a vacuolar Na+/H+ exchanger termed InNHX1. The genome of I. nil carries one copy of the Pr (or InNHX1) gene and its pseudogene, and it showed functional complementation to the yeast nhx1 mutation. The mutant of I. nil, called purple (pr), showed a partial increase in the vacuolar pH during flower-opening and its reddish-purple buds change into purple open flowers. The vacuolar pH in the purple open flowers of the mutant was significantly lower than that in the blue open flowers. The InNHX1 gene is most abundantly expressed in the petals at around 12 h before flower-opening, accompanying the increase in the vacuolar pH for the blue flower coloration. No such massive expression was observed in the petunia flowers. Since the NHX1 genes that promote the transport of Na+ into the vacuoles have been regarded to be involved in salt tolerance by accumulating Na+ in the vacuoles, we can add a new biological role for blue flower coloration in the Japanese morning glory by the vacuolar alkalization.

Biological Transport↗
PubMed2001

Hypoglycemic effect of a hot-water extract from defatted sesame (Sesamum indicum L.) seed on the blood glucose level in genetically diabetic KK-Ay mice.

Genetically diabetic (type II) KK-Ay mice, male and 5 weeks of age, were divided into one group of 12 mice that were fed on a basal (BAS) diet and three groups of 6 mice each that were fed on the test diets for 4 weeks. Each test diet contained 4.0% of the hot-water extract (HES) from defatted sesame (Sesamum indicum L.) seed, 1.4% of the water eluent fraction (WFH) of HES or 0.7% of the methanol eluent fraction (MFH) of HES from a glass column packed with HP-20 resin. At the end of the feeding period, the BAS group was divided into the MAL and MALH groups which were respectively force-fed with 1 ml per mouse of a 20% maltose solution in water with or without 4.0% HES. The plasma glucose concentration and amount of urinary excreted glucose were lower from the HES and MFH diets than from the BAS and WFH diets. The levels of plasma glucose and serum insulin were lower in the MALH group than in the MAL group. These results indicate that HES and MFH had a reductive effect on the plasma glucose concentration of KK-Ay mice, and this effect is suggested to have been caused by the delayed glucose absorption.

Age Factors↗
PubMed2001

[Efficacy of simultaneous bolus injection of lidocaine with propofol on pain caused by propofol injection].

To investigate the effect of simultaneous bolus injection of 2% lidocaine 2 ml on preventing the pain on propofol injection, 80 patients were randomly assigned to one of four study groups; Group I received simultaneous bolus injection of 2% lidocaine 2 ml with infusion of propofol; Group II received bolus injection of saline 2 ml, 10 s before the start of infusion of propofol-lidocaine mixture; Groups III and IV received bolus injections of lidocaine and saline, separately 10 s before starting propofol infusion. Incidence of propofol-induced pain was significantly more frequent (P < 0.001) in Group IV (70%) than in the other groups (20% each). Number of patients who were satisfied with this anesthetic induction and requested for the same induction method in the next anesthesia was significantly larger in the groups receiving lidocaine (P < 0.05). Simultaneous bolus injection of lidocaine with propofol showed a similar clinical efficacy compared with both preadministration and premixing of lidocaine in preventing the propofol-induced pain.

Adult↗
PubMed2000

Synergistic cooperation between Sp1 and Smad3/Smad4 mediates transforming growth factor beta1 stimulation of alpha 2(I)-collagen (COL1A2) transcription.

Transforming growth factor-beta1 (TGFbeta) is a strong activator of extracellular matrix accumulation. TGFbeta stimulates the gene coding for human alpha2(I)-collagen (COL1A2) by inducing binding of an Sp1-containing complex to an upstream promoter element (TGFbeta responsive element or TbRE) that contains a CAGA box. Here we report that the CAGA box of the TbRE is the binding site of the Smad3/Smad4 complex, and that the binding of the complex is required for TGFbeta-induced COL1A2 up-regulation. Recombinant Smad3 and Smad4 bind in vitro to the CAGA box of COL1A2; TGFbeta treatment of cultured fibroblasts induces Smad3/Smad4 binding to the TbRE; transient overexpression of Smad3 and Smad4 in fibroblasts transactivates TbRE-driven transcription; and COL1A2 gene up-regulation by TGFbeta is abolished in cells stably transfected with plasmids that express dominant negative forms of Smad3 or Smad4. In Sp1-deficient Drosophila Schneider cells, there was cooperative synergy between Smad3/Smad4 and Sp1 at the TbRE site. The analysis also emphasized the requirement of both Sp1- and Smad-binding sites for optimal promoter transactivation. In cells stably transfected with a plasmid expressing a dominant negative form of Sp1, the synergy was shown to be promoter-specific and dependent on the binding of Sp1 to the TbRE. Interestingly, overexpression of dominant negative Sp1 was found to block the antagonistic signal of tumor necrosis factor-alpha on COL1A2 transcription, as well. These results provide the first linkage between the Smad3 and Smad4 proteins and TGFbeta stimulation of type I collagen biosynthesis.

3T3 Cells↗