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Biomedical subjects

M Yamauchi

Publications and source records attributed to M Yamauchi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Hepatocyte-targeted in vivo gene expression by intravenous injection of plasmid DNA complexed with synthetic multi-functional gene delivery system.

To achieve hepatocyte-targeted in vivo gene expression, a carrier that controls both the tissue and intracellular distribution of DNA was designed and synthesized. A cationic polymer, poly(L-ornithine) (pOrn), was modified first with galactose, then with a fusigenic peptide (mHA2) to obtain Gal-pOrn-mHA2. When applied with Gal-pOrn-mHA2 to asialoglycoprotein receptor-positive cells, fluorescein-labeled DNA showed a diffuse profile, suggesting the release of DNA from endosomes and/or lysosomes by the carrier. Then the biodistribution and gene expression after intravenous injection of DNA complexes (10 microg DNA per mouse) were examined. After injection of [32P]DNA/Gal-pOrn-mHA2, about 60% of the radioactivity was recovered in the liver, mostly in parenchymal cells. A large amount (81 ng/g tissue) of transgene product (luciferase) was detected in the liver of mice injected with DNA/Gal-pOm-mHA2, which was 280-fold greater than that obtained with DNA/DOTMA:Chol liposomes (50 microg DNA). Prior administration of galactosylated albumin reduced the gene expression to 1/100, indicating the asialoglycoprotein receptor-mediated gene transfer in liver parenchymal cells, ie hepatocytes. The luciferase activity in hepatocytes contributed more than 95% of the total activity in all the tissues examined. Thus, hepatocyte-targeted in vivo gene expression was achieved by the intravenous injection of DNA complex with the multifunctional gene carrier.

Animals↗
PubMed2000

Coexistence of psoriasis and linear IgA bullous dermatosis.

Linear IgA bullous dermatosis (LABD) is characterized by IgA autoantibodies against components of the basement membrane zone (BMZ). A 97-kDa protein is one of the major autoantigens associated with this disease. We report a 68-year-old man who developed LABD after a 3-year history of psoriasis and in the context of active hepatitis C virus infection. He had been treated with cyclosporin for psoriasis for about 9 months. Histologically, there was a subepidermal blister containing neutrophils and eosinophils with lymphocytes infiltrating predominantly in the dermis. Direct immunofluorescent staining showed linear IgA deposition at the BMZ. The patient's IgA autoantibodies bound exclusively to the epidermal side of 1 mol/L salt-split normal human skin. Immunoblot analysis identified a 97-kDa autoantigen in epidermal extracts. This appears to be the first case of LABD with IgA autoantibodies against a 97-kDa autoantigen, associated with psoriasis and hepatitis C virus infection.

Aged↗
PubMed2000

Genomic structure and chromosomal localization of the human hepatocyte growth factor activator inhibitor type 1 and 2 genes.

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are recently discovered Kunitz-type serine protease inhibitors which can be purified and cloned from human stomach cancer cell line MKN45 as specific inhibitors against hepatocyte growth factor activator (HGFA). HAI-2 was identical with the protein originally reported as placental bikunin. Both proteins contain two Kunitz inhibitor domains (KDs), of which the first domain (KD1) is mainly responsible for the inhibitory activity against HGFA, and are expressed ubiquitously in various tissues. In this study, we cloned the genes coding for these two structurally similar proteins by screening of human genomic bacterial artificial chromosome (BAC) library and their genomic structures were compared. HAI-1 and -2 genes consist of 11 and 8 exons spanning 12 kbp and 12.5 kbp, respectively. Three exons were inserted between KD1 and KD2 of each gene, of which the middle one was the low-density lipoprotein (LDL) receptor-like domain (HAI-1) and the testis specific exon (HAI-2). Apparently homologous regions between HAI-1 and -2 were not found in 5'-flanking region and neither TATA nor CAAT box was present. The genes were mapped to chromosome 15q15 (HAI-1) and 19q13.11 (HAI-2). These results suggested that although HAI-1 and -2 genes might be derived from same ancestor gene, they acquired distinctive in vivo roles during their evolution.

Amino Acid Sequence↗
PubMed2000

Nicorandil stimulates release of adenyl purines from porcine coronary artery.

1. To clarify the mechanism of the cardioprotective effect of nicorandil (2-nicotinamidoethyl-nitrate ester), the effects of nicorandil and nitric oxide (NO) donors on the release of ATP, ADP, AMP and adenosine from arterial segments and cultured endothelial cells of the porcine coronary artery were examined. 2. Nicorandil significantly increased the release of total adenyl purines from arterial segments and from cultured endothelial cells. 3. Cromakalim, an ATP-sensitive K+ channel opener, did not affect the release of total adenyl purines from coronary artery segments. 4. s-Nitroso-N-acetyl-D,L-penicillamine and isosorbide dinitrate, NO donors, significantly increased the release of total adenyl purines from coronary artery segments. 5. These results demonstrate that nicorandil stimulates ATP release from the coronary artery by acting not as an ATP-sensitive K+ channel opener, but as a nitrate, thus suggesting the cardioprotective properties of nicorandil.

Adenine Nucleotides↗
PubMed2000

Genetic polymorphisms of interleukin-1beta in association with the development of alcoholic liver disease in Japanese patients.

OBJECTIVE: Cytokine interleukin-1beta plays a central role in the inflammation process. Serum levels of IL-1beta are elevated in patients with alcoholic liver disease (ALD), especially in those with cirrhosis and alcoholic hepatitis. Recently, the presence of genetic polymorphisms of this cytokine was confirmed. The aim of this study was to determine whether IL-1beta polymorphisms are associated with the development of ALD. METHODS: We examined the frequency of two polymorphisms in the IL-1beta gene located in promoter -511 and exon 5 +3953 locus by restriction fragment length polymorphisms in 142 male patients with ALD, 30 heavy drinkers without ALD, and 218 healthy controls. RESULTS: The carriers of -511 IL-1beta allele 2 were present significantly more often in patients with alcoholic cirrhosis than in those with noncirrhotic ALD (p = 0.026), heavy drinkers without ALD (p = 0.001), and healthy controls (p = 0.032). The frequencies of allele 2 and heterozygotes of +3953 polymorphism were both significantly higher in heavy drinkers without ALD than in patients with ALD (allele, p = 0.030; genotype, p = 0.027) and healthy controls (allele, p = 0.047; genotype, p = 0.043). The haplotype, IL-1beta -511 allele 2/+3953 allele 1 was associated with the development of alcoholic cirrhosis (p < 0.05). CONCLUSIONS: These results suggest that IL-1beta polymorphisms may be related to the development of ALD in Japanese alcoholics.

Adult↗
PubMed2000

Unique enamel phenotype associated with amelogenin gene (AMELX) codon 41 point mutation.

Different mutations in the amelogenin gene (AMELX) result in the markedly different enamel phenotypes that are collectively known as amelogenesis imperfecta (AI). We hypothesize that unique phenotypes result from specific genetic mutations. The purpose of this study was to characterize the enamel compositional and structural features associated with a specific AMELX mutation in three families with X-linked AI. We performed mutational analysis by amplifying AMELX exons and sequencing the products. Permanent and primary affected (N = 6) and normal (N = 3) teeth were collected and examined by light, scanning, and transmission electron microscopy. Enamel proteins were evaluated by immunolocalization of amelogenin and amino acid analysis. AI-affected individuals all shared a common AMELX point mutation (C to A change at codon 41). The dental phenotypic findings were remarkably consistent in all affected individuals. The AI enamel was opaque, with numerous prism defects or holes encompassing the entire prism width. Affected crystallites appeared more radiolucent and morphologically less uniform, compared with that of normal enamel. Immunogold labeling with anti-amelogenin antibodies localized amelogenin to the crystallites but not to the inter-crystalline spaces. No immunogold labeling was seen in normal enamel. There was an increased and amelogenin-like protein content in AI enamel (0.95%) compared with normal enamel (0.13%). We conclude that this codon 41 C to A missense point mutation, in a highly conserved region of the AMELX gene, results in a remarkably consistent phenotype.

Amelogenesis Imperfecta↗
PubMed2000

A novel minisatellite repeat expansion identified at FRA16B in a Japanese carrier.

Previously, the allelic expansion of a 33-bp AT-rich minisatellite repeat has been reported to cause FRA16B, a distamycin A-inducible fragile site. Here, we identified a novel 35-bp minisatellite repeat at FRA16B in a Japanese carrier. The nucleotide sequence of the 35-bp minisatellite was highly AT-rich and nearly identical to the 33-bp one but with insertion of two nucleotides, thymine and adenine. The copy number of the AT-rich minisatellite was 21 in total in the carrier, while only a few copies of the 33-bp minisatellite were present in a non-carrier Japanese subject. These results suggest that the molecular mechanism involved in the allelic expansion of the minisatellite repeat in FRA16B recognizes both minisatellites, the 33-bp one and the 35-bp one, as an amplicon. These observations were different from the ones at folate-sensitive fragile sites, where the CCG triplet repeat was commonly involved in the allelic expansion. Although a slight reduction in AT content (95% > 90%) in the region of minisatellite expansion in the carrier subject was observed, both AT-content and length of the highly AT-rich region seem to play important roles in the cytogenetic expression of the distamycin A-inducible fragile site. In another normal subject, without fragile site expression, allelic expansion involving the 33-bp minisatellite was observed, and the length of the AT-rich DNA region was increased up to approximately 1000 bp. Since the length of the AT-rich minisatellite region was increased up to approximately 1,100-bp in the carrier subject, the threshold length for the cytogenetic expression of the AT-rich DNA region may be between about 1,000-bp and 1,100-bp.

Asian People↗
PubMed2000

Cementum-forming cells are phenotypically distinct from bone-forming cells.

Normal human cementum-derived cells (HCDCs), expanded in vitro, formed mineralized matrix when attached to a ceramic carrier and transplanted subcutaneously into immunodeficient mice. The mineralized matrix elaborated by transplanted HCDC exhibited several features identical to cementum in situ and was significantly different from bone deposited by similarly transplanted human bone marrow stromal cells (BMSCs). No bone marrow formation and very few or no tartrate-resistant acid phosphatase (TRAP)-positive cells (osteoclasts and osteoclastic precursors) were found in HCDC transplants. In contrast, in BMSC transplants both hematopoiesis and TRAP-positive cells were routinely observed. Furthermore, compared with BMSC-derived matrix, HCDC-derived matrix was less cellular, numerous empty lacunae were present, and fewer cells were found on the cementum matrix/ceramic carrier interface. The organization of collagen fibers in HCDC-derived matrix, as visualized by using the Picrosirus red staining method, was similar to cementum, with typical unorganized bundles of collagen fibers. In contrast, bone matrix elaborated by transplanted BMSC had lamellar structure, identical to mature bone in situ. Finally, cementocytes embedded in the cementum-like matrix were immunopositive for fibromodulin and lumican, whereas osteocytes within the bonelike matrix were negative. This pattern is consistent with the cementum and bone in situ, respectively. These results indicate that human cementum cells are phenotypically distinct from bone cells and provide further validation of the combined in vitro/in vivo model of human cementogenesis recently developed in our laboratory.

Adolescent↗
PubMed2000

In vitro apatite induction by phosphophoryn immobilized on modified collagen fibrils.

Noncollagenous phosphoproteins that interact with type I collagen are thought to nucleate the mineral phase to collagen network of mineralized tissues. Previously, we found that phosphophoryn cross-linked to type I collagen was an effective nucleator of apatite. Here, we investigated the potential role of collagen telopeptide structure on this nucleation. We used pepsin and sodium borohydride (NaBH4) to modify the telopeptide region and reducible cross-links in the collagen fibrils and determined the effect on mineral induction by phosphophoryn cross-linked to it. The amount of phosphophoryn cross-linked to NaBH4-reduced collagen fibrils was higher than that to intact (unmodified) collagen fibrils. However, the amount of phosphophoryn cross-linked to collagen that lacked the telopeptides (atelocollagen) was 25% of that cross-linked to intact collagen fibrils. Each preparation was incubated at 37 degrees C in metastable calcium phosphate solutions that did not spontaneously precipitate. Apatite was induced by phosphophoryn cross-linked to intact collagen fibrils at 15.0 h whereas phosphophoryn cross-linked to reduced collagen fibrils induced apatite formation after 10.9 h. Enough phosphophoryn was cross-linked to atelocollagen to induce mineral formation, but it did not. The failure of the phosphophoryn-atelocollagen complex to nucleate mineral might have been caused by a cross-linking pattern in the helical portion of the collagen molecule that did not promote the growth of the calcium-phosphate clusters into nuclei. The present study indicates that the telopeptide domains of type I collagen play a role in the interaction with phosphophoryn, which is critical for the nucleation process.

Animals↗
PubMed2000

Effects of saiko-ka-ryukotsu-borei-to on spontaneous locomotor activity in mice. Oriental Medicine Research Group.

The effects of the Japanese Kampo (herbal) medicine, Saiko-ka-ryukotsu-borei-to, on spontaneous locomotor activity were studied in mice. Saiko-ka-ryukotsu-borei-to (60 mg, 150 mg and 300 mg/kg/day) was administered for 14 consecutive days in the drinking water and spontaneous locomotor activity was measured for 60 min by a photocell ambulometer. Saiko-ka-ryukotsu-borei-to (60 mg/kg/day) significantly increased the total activity count on the 11th day after the start of administration when compared to vehicle control, whereas failed to significantly affect the activity on the 2nd, 5th, 8th and 14th days. A similar significant increase was also found with a higher dose (150 mg/kg/day) on the 8th day after the start of administration. However, the highest dose (300 mg/kg/day) did not significantly affect locomotor activity throughout the experimental period. We have previously reported that Saiko-ka-ryukotsu-borei-to, at a dose of 60 mg/kg/day, enhances escape attempts assessed by water-wheel rotations in a mouse model of despair, particularly on the 8th, 11th and 14th days after the start of chronic treatment. However, at higher doses (150 and 300 mg/kg/day), Saiko-ka-ryukotsu-borei-to decreases the escaped attempts on the 5th and 8th days after the treatment. It is therefore concluded that the previously reported changes in escape attempts of mice are not associated with the changes in their spontaneous locomotor activity.

Administration, Oral↗
PubMed2000

Ethanol patch test: a simple method for identifying the effectiveness of cyanamide in alcoholics.

BACKGROUND: To identify the pharmacological effectiveness of cyanamide, 144 alcoholics treated with cyanamide were subjected to a test that used an acetaldehyde dehydrogenase (ALDH) inhibitor, the ethanol patch test, which is considered to be a good indicator of ALDH2 phenotype. METHODS: We placed 100 microl of 70% ethanol on a lint pad and, as a control, placed the same volume of distilled water on a second pad. The ethanol patch test was performed on 144 alcoholics more than 2 weeks after abstinence from alcohol before and after treatment with cyanamide for 1 week. The dose of cyanamide was increased up to 150 mg until the patch test yielded a positive result. RESULTS: In the ethanol patch test, 36 alcoholics (25.0%) gave a positive result before treatment with cyanamide and might have been ALDH2(1)/2(2) heterozygotes. Among 108 alcoholics who were not positive, the distribution of the cyanamide dose that yielded a positive ethanol patch test result was 30 mg in 42 cases (38.9%), 50 mg in 33 cases (30.6%), 70 mg in 5 cases (4.6%), 100 mg in 6 cases (5.6%), and 150 mg in 2 cases (1.9%). Prevalence of liver cirrhosis was significantly higher in alcoholics who showed a positive ethanol patch test result at doses of less than 50 mg cyanamide than those at doses more than 70 mg (p = 0.029). The prevalence of adverse effects was significantly higher in alcoholics who showed a positive ethanol patch test result at doses of more than 70 mg than at doses of less than 50 mg cyanamide (p = 0.002). CONCLUSIONS: The ethanol patch test is a useful method for identifying pharmacological effectiveness of cyanamide and may reduce the prevalence of side effects in cyanamide-treated alcoholics.

Adult↗
PubMed2000

Bone biochemistry in rat femoral diaphysis after space flight.

The aim of this experiment was to identify the location of the biochemical changes associated with depressed mineralization during space flight. We carried out biochemical analysis of 4 sections of the femoral diaphyses from 107 day old male rats flown aboard Cosmos 2044 Biosatellite for 16 days. Control femurs were preflight, vivarium, synchronous for feed, cage and temperature exposure, and a flight simulation model. Distal sections in both the flight and synchronous femurs showed mineral deficits associated with reduced levels of the reducible cross-link product of type I collagen, dehydro-dihydroxylysinonorleucine (deH-DHLNL) (p<.05). Unloaded bones in the ground based flight simulation model showed changes in cross-links similar to flight and synchronous controls, but were not associated with the mineral deficit. Mean values of elements measured in each section of all groups revealed significant associations (p<.005) between the non-collagenous protein, osteocalcin and calcium (r=0.774), phosphorus (r=-.624) and deH-DHLNL/deH-HLNL (r=.883). The ratio of the nonreducible cross-link, pyridinoline, to its lysl analogue, deoxypyridinoline, was consistently lower in the distal than proximal sections of the groups tested. None of the changes during space flight were unique to flight bone. The most significant and extensive changes in bone composition, i.e. mineral deficits associated with changes in both osteocalcin and reducible cross-links, were located in the distal section of the diaphysis of the femur.

Amino Acids↗
PubMed1999

The natriuretic peptide clearance receptor locally modulates the physiological effects of the natriuretic peptide system.

Natriuretic peptides (NPs), mainly produced in heart [atrial (ANP) and B-type (BNP)], brain (CNP), and kidney (urodilatin), decrease blood pressure and increase salt excretion. These functions are mediated by natriuretic peptide receptors A and B (NPRA and NPRB) having cytoplasmic guanylyl cyclase domains that are stimulated when the receptors bind ligand. A more abundantly expressed receptor (NPRC or C-type) has a short cytoplasmic domain without guanylyl cyclase activity. NPRC is thought to act as a clearance receptor, although it may have additional functions. To test how NPRC affects the cardiovascular and renal systems, we inactivated its gene (Npr3) in mice by homologous recombination. The half life of [125I]ANP in the circulation of homozygotes lacking NPRC is two-thirds longer than in the wild type, although plasma levels of ANP and BNP in heterozygotes and homozygotes are close to the wild type. Heterozygotes and homozygotes have a progressively reduced ability to concentrate urine, exhibit mild diuresis, and tend to be blood volume depleted. Blood pressure in the homozygotes is 8 mmHg (1 mmHg = 133 Pa) below normal. These results are consistent with the sole cardiovascular/renal function of NPRC being to clear natriuretic peptides, thereby modulating local effects of the natriuretic peptide system. Unexpectedly, Npr3 -/- homozygotes have skeletal deformities associated with a considerable increase in bone turnover. The phenotype is consistent with the bone function of NPRC being to clear locally synthesized CNP and modulate its effects. We conclude that NPRC modulates the availability of the natriuretic peptides at their target organs, thereby allowing the activity of the natriuretic peptide system to be tailored to specific local needs.

Animals↗
PubMed1999

Structural studies on sugar chains of carbohydrate-deficient transferrin from patients with alcoholic liver disease using lectin affinity electrophoresis.

It is well-known that microheterogeneity of human serum transferrin observed in alcoholics manifests as sialic acid-deficient transferrin isoforms, otherwise known as carbohydrate-deficient transferrin (CDT). A recent study demonstrated that serum CDT lacked one or both of the entire carbohydrate chains but the investigation required several troublesome procedures. The aim of the present study was to confirm the sugar chain structures of serum transferrin, and of serum CDT in particular, from patients with alcoholic liver disease (ALD) using conventional lectin affinity electrophoresis which might be useful in the clinical setting. The serum CDT obtained from ALD-patients was partially purified using an anion exchanger. Serum transferrin and the partially purified serum CDT were investigated by concanavalin A (Con A)- and Datura stramonium agglutinin (DSA)-affinity electrophoresis followed by antibody-affinity blotting and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with Western blotting. By Con A-affinity electrophoresis, serum CDT was separated into weakly reactive and nonreactive transferrins which showed slower electrophoretic mobilities than those from the healthy controls. Moreover, nearly all of the serum CDT was nonreactive with DSA. On SDS-PAGE, the molecular masses of serum CDT were estimated to be approximately 75 and 72 kDa, which corresponded to those of partially and completely deglycosylated transferrin obtained from the healthy controls (78 kDa), respectively. In conclusion, these results indicated that the sugar chain structures of serum CDT from patients with ALD show not merely a loss of terminal sialic acids, but also the absence of asparagine-N-linked oligosaccharides.

Antibody Affinity↗
PubMed1999

Quantitative and qualitative hemispheric asymmetry for processing Japanese kana.

Native Japanese speakers identified three-letter kana stimuli presented to the left visual field and right hemisphere (LVF/RH), to the right visual field and left hemisphere (RVF/LH), or to both visual fields and hemispheres simultaneously (BILATERAL trials). There were fewer errors on RVF/LH and BILATERAL trials than on LVF/RH trials. Qualitative analysis of error patterns indicated that there were many fewer errors of first-letter identification than of last-letter identification, suggesting top-to-bottom scanning of the kana characters. In contrast to similar studies presenting nonword letter trigrams to native English speakers, qualitative error patterns were identical for the three visual field conditions. Taken together with the results of earlier studies, the results of the present experiment indicate that the ubiquitous RVF/LH advantage reflects a left-hemisphere superiority for phonetic processing that generalizes across specific languages. At the same time, qualitative aspects of hemispheric asymmetry differ from one language to the next and may depend on such things as the way in which individual characters map onto the pronunciation of words and nonwords.

Brain↗
PubMed1999

Persistence of bone collagen cross-links in skeletons of the Nuraghi population living in Sardinia 1500-1200 B.C.

Bone collagen has a specific molecular ultrastructure which can be proved by birefringence. This protein, forming the main organic component of bone tissue, is known to survive millennia in paleontological bones and teeth. Birefringence of bone collagen obtained from the skeletons of the Nuraghi population living in Sardinia c-ca 1500 years B.C. was found previously by the use of polarizing microscopy [1]. In this paper, using high pressure liquid chromatography (HPLC) techniques, we show the existence of bone collagen cross-links preserved in Nuraghi skeletons after more than 3000 years.

Amino Acids↗