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Biomedical subjects

H Ueda

Publications and source records attributed to H Ueda.

At least 469 records · Page 26Linked to original sources
PubMed1995

Synthesis and biological properties of substituted 1,4-dihydro-5-methyl-4-oxo-3-quinolinecarboxylic acids.

A series of substituted 1-cyclopropyl-6-fluoro-1, 4-dihydro-5-methyl-4-oxo-3-quinoline carboxylic acids was synthesized and tested for their in vitro and in vivo antibacterial activity. The introduction of a methyl group at the 5-position of quinoline nucleus enhanced characteristically the antibacterial activity against Gram-positive bacteria, including Streptococcus pneumoniae, which is a major pathogen in the respiratory tract infection, while retaining Gram-negative activity. Among them, 1-cyclopropyl-6-fluoro-1, 4-dihydro-5-methyl-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinolinecarboxyli c acid hydrochloride (grepafloxacin) exhibited potent in vitro antibacterial activity against Gram-positive bacteria such as Streptococcus pneumoniae and high in vivo efficacy on the experimental systemic infections caused by the Gram-positive and -negative bacteria tested. It also showed a high distribution to the lung and bronchoalveolar lavage fluid in comparison to reference drugs and is now undergoing clinical evaluation.

4-Quinolones↗
PubMed1995

Functional inactivation but not structural mutation of p53 causes liver cancer.

Structural mutations in the p53 gene are seen in virtually every form of human cancer. To determine whether such mutations are important for initiating tumorigenesis, we have been studying hepatocellular carcinoma, in which most cases are associated with chronic hepatitis B virus infections. Using a transgenic mouse model where expression of a single HBV gene product, the HBx protein, induces progressive changes in the liver, we show that tumour development correlates precisely with p53 binding to HBx in the cytoplasm and complete blockage of p53 entry into the nucleus. Analysis of tumour cell DNA shows no evidence for p53 mutation, except in advanced tumours where a small proportion of cells may have acquired specific base substitutions. Our results suggest that genetic changes in p53 are late events which may contribute to tumour progression.

Animals↗
PubMed1995

Correlation between the induction of a gene for delta 1-pyrroline-5-carboxylate synthetase and the accumulation of proline in Arabidopsis thaliana under osmotic stress.

The isolation and characterization is reported of a cDNA for delta 1-pyrroline-5-carboxylate (P5C) synthetase (cAtP5CS), an enzyme involved in the biosynthesis of proline, from a cDNA library prepared from a dehydrated rosette plant of Arabidopsis thaliana. Southern blot analysis suggested that only one copy of the corresponding gene (AtP5CS) is present in A. thaliana. The deduced amino acid sequence of the P5CS protein (AtP5CS) from A. thaliana exhibited 74% homology to that of the P5CS from Vigna aconitifolia. Northern blot analysis revealed that the gene for P5CS was induced by dehydration, high salt and treatment with ABA, while it was not induced by heat or cold treatment. Moreover, the simultaneous accumulation of proline was observed as a result of the former treatments in A. thaliana. A cDNA for P5C reductase (cAtP5CR) was also isolated from A. thaliana and Northern blot analysis was performed. The AtP5CR gene was not induced to a significant extent by dehydration or high-salt stress. These observations suggest that the AtP5CS gene plays a principal role in the biosynthesis of proline in A. thaliana under osmotic stress.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1995

Altered basal release and depressor effect of L-DOPA in the nucleus tractus solitarii of spontaneously hypertensive rats.

1. L-DOPA as a probable neurotransmitter of baroreceptor afferents functions as a tonic to mediate cardiodepressor control in the nucleus tractus solitarii (NTS). We attempted to clarify further whether a transmitter-like L-DOPA system is altered in NTS of adult spontaneously hypertensive rats (SHR). 2. By microdialysis of left NTS area, the basal L-DOPA release was lower in SHR than in Wistar-Kyoto (WKY) rats. This release was partially inhibited by tetrodotoxin (TTX, 1 mu mol/L) to a similar degree in both strains. TTX-sensitive L-DOPA release was lower in SHR than in WKY. 3. L-DOPA (10-300 ng) and L-glutamate (3-100 ng) microinjected into left NTS produced dose-dependent hypotension and bradycardia. No difference of responses to L-glutamate was seen in either strain. However, depressor but not bradycardic responses to L-DOPA at higher doses were slightly greater in SHR than in WKY. 4. In caudal dorsomedial medulla including NTS, tyrosine hydroxylase activity was increased in SHR compared to WKY, while there was no difference in either strain of L-aromatic amino acid decarboxylase activity. 5. Impaired tonic neuronal activity to release L-DOPA in NTS may be involved in the maintenance of hypertension in SHR. An increase in sensitivity of a recognition site for L-DOPA seems to occur as a compensatory mechanism for impairment of the neuronal activity.

Animals↗
PubMed1995

Altered basal release and pressor effect of L-DOPA in the rostral ventrolateral medulla of spontaneously hypertensive rats.

1. Transmitter-like L-DOPA functions as a tonic to produce postsynaptic cardiopressor responses in the rostral ventrolateral medulla (RVLM) of rats. We attempted to clarify whether a transmitter-like L-DOPA system is altered in the RVLM of spontaneously hypertensive rats (SHR) to maintain the hypertension. 2. By microdialysis of left RVLM area, the basal L-DOPA release was higher in SHR than in Wistar-Kyoto (WKY) rats. This release was partially inhibited by tetrodotoxin (TTX, 1 mu mol/L) to a similar degree in both strains. TTX-sensitive L-DOPA release was higher in SHR than in WKY. 3. L-DOPA (10-600 ng) and L-glutamate (10-300 ng) microinjected into left RVLM produced dose-dependent hypertension and tachycardia. Pressor but not tachycardiac responses to L-DOPA at lower doses were slightly greater in SHR than in WKY, whereas no difference to L-glutamate was observed in either strain. 4. In RVLM regions, there was no difference of tyrosine hydroxylase activity in SHR or WKY; however, L-aromatic amino acid decarboxylase activity was lower in SHR than in WKY. 5. Enhanced presynaptic neuronal L-DOPA release, including a decrease in decarboxylation and sensitization of postsynaptic pressor sites to L-DOPA in RVLM, may be involved in the maintenance of hypertension in SHR.

Animals↗
PubMed1995

Immunocytochemical study of dystrophin-related protein in the rat retina.

Dystrophin-related protein (DRP) has been reported to exist in the brain, but there are no reports describing its existence in the retina. In the present study, DRP localization was examined in rat retinas by immunohistochemistry in comparison to dystrophin localization. Rat retinas were fixed using paraformaldehyde and immunostained with one antidystrophin antibody and two anti-DPR antibodies. Dystrophin was observed in the outer plexiform layer, but DRP was recognized in ganglion cell layer and inner nuclear layer, but not in the outer plexiform layer. DRP has been thought to exist under the plasma membrane, but the present study clarified that DRP in the retina was localized throughout the perikaryon of the neuronal cells. These results suggest that DRP may play a distinct role from that of dystrophin in the rat retina.

Amino Acid Sequence↗
PubMed1995

Identification of a new susceptibility locus for insulin-dependent diabetes mellitus by ancestral haplotype congenic mapping.

The number and exact locations of the major histocompatibility complex (MHC)-linked diabetogenic genes (Idd-1) are unknown because of strong linkage disequilibrium within the MHC. By using a congenic NOD mouse strain that possesses a recombinant MHC from a diabetes-resistant sister strain, we have now shown that Idd-1 consists of at least two components, one in and one outside the class II A and E regions. A new susceptibility gene (Idd-16) was mapped to the < 11-centiMorgan segment of chromosome 17 adjacent to, but distinct from, previously known Idd-1 candidates, class II A, E, and Tap genes. The coding sequences and splicing donor and acceptor sequences of the Tnfa gene, a candidate gene for Idd-16, were identical in the NOD, CTS, and BALB/c alleles, ruling out amino acid changes in the TNF molecule as a determinant of insulin-dependent diabetes mellitus susceptibility. Our results not only map a new MHC-linked diabetogenic gene(s) but also suggest a new way to fine map disease susceptibility genes within a region where strong linkage disequilibrium exists.

Animals↗
PubMed1995

Soluble expression of a synthetic gene for human translation initiation factor 4E in Escherichia coli.

In order to obtain the active form of recombinant human initiation factor (eIF) 4E effectively, an artificial synthetic gene was cloned into an expression vector (pMAL-p2) and the soluble expression was attempted in Escherichia coli under the control of a tac promoter. Two expression systems were finally constructed as a fusion protein with maltose-binding protein, which contain a recognition sequence for the site specific protease alpha-thrombin and factor Xa, respectively. Most of the fusion protein was induced as a soluble form. The soluble human eIF-4E digested from the fusion protein showed binding specificity for the m7GTP affinity column.

Amino Acid Sequence↗
PubMed1995

Improvement of cisplatin toxicity and lethality by juzen-taiho-to in mice.

The effects of oral treatment with 1-, 5-, 10- and 20-fold the usual daily dose of Juzen-taiho-to on the nephrotoxicity, immunosuppression, hepatic toxicity and gastrointestinal toxicity caused by i.p. administration of 3.0 mg/kg cisplatin (CDDP) 9 times (on days 3, 4, 5, 6, 7, 8, 10, 11, and 12) were examined in ddY mice inoculated with sarcoma 180 (S-180) cells on day 1. The increase in blood urea nitrogen, serum creatinine, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminases and relative stomach weight and decrease in white blood cell count, platelet count, relative spleen and thymus weight, food intake and body weight caused by CDDP were inhibited to nearly the control levels without reducing the antitumor activity of CDDP against S-180 by the oral treatment with either 10-fold (1.7 g/kg) or 20-fold (3.4 g/kg) the usual daily dose of Juzen-taiho-to 12 times (on days 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, and 15). All the mice receiving 4.5, 6.0, 7.5, 9.0, and 12.0 mg/kg CDDP died by day 12, while treatment with 3.4 g/kg Juzen-taiho-to efficiently prolonged the survival time. These findings indicate that Juzen-taiho-to may provide protection against most clinical toxicity caused by CDDP, and Juzen-taiho-to may allow us to administer a much higher dose of CDDP in clinical therapy.

Animals↗
PubMed1995

Protective effect of juzen-taiho-to against carboplatin-induced toxic side effects in mice.

The effect of an oral treatment with the Kampo formulation Juzen-taiho-to on the toxicity caused by the intraperitoneal administration of 15 mg/kg carboplatin (CBDCA) 9 times (on days 3, 4, 5, 6, 7, 8, 10, 11 and 12) was examined in ddY mice, which were subcutaneously inoculated with sarcoma 180 (S-180) cells on day 1. White blood cell counts, platelet counts, bone marrow cell counts, relative spleen and thymus weight, food intake and body weight decreased significantly, to about 29%, 13%, 14%, 59%, 36%, 42% and 72% of the control levels, respectively, and serum glutamic-oxaloacetatic transaminase, serum glutamic-pyruvic transaminase and relative stomach weight increased significantly, to about 4, 6 and 3 times the control levels, respectively, by the treatment with CBDCA. However, the blood urea nitrogen and serum creatinine were only slightly increased compared to the control value. Co-treatment with 1.7 g/kg of a lyophilized water extract of Juzen-taiho-to once a day 12 times (on days 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14 and 15) prevented both the decreases and increases caused by CBDCA to near the control levels without reducing the antitumor activity of CBDCA against S-180. The inhibitory effect of Juzen-taiho-to against CBDCA-induced myelosuppression was similar to that against 3.0 mg/kg cisplatin (CDDP) 9 times, while CBDCA-induced myelosuppression was more serious in comparison with CDDP. Therefore, these findings indicate that Juzen-taiho-to could be an effective drug for protecting against the side effects induced by CBDCA in the clinic as well as by CDDP.

Animals↗
PubMed1995

[Gene expression of human eukaryotic initiation factor-4E for protein synthesis and study of its recognition mechanism of mRNA cap structure].

Being stimulated by the insights from model studies that (i) the intimate combination of hydrogen-bonding pairing and aromatic stacking interactions is important for the specific binding of guanine base by peptide and (ii) the pi-pi stacking force of Trp is significantly strengthened by the guanine N7-methylation (m7G), this research project was started, because (a) the mRNA cap structure is characterized by the existence of m7G and (b) an eukaryotic initiation factor-4E (eIF-4E), a protein which specifically recognizes the mRNA cap structure and opens the protein biosynthesis, contains 8 Trp residues irrespective of its relatively low molecular weight of about 25 kDa. In order to prepare the sufficient amount of sample for carrying out the analysis of the recognition mechanism of mRNA cap structure by eIF-4E at the atomic level, firstly, the expression of human eIF-4E gene in Escherichia coli was attempted. An artificial gene encoding for human eIF-4E was chemically synthesized and succeeded in the expression with two different forms, i.e., as a fusion protein with human growth hormone and a direct expression of soluble protein. The isolation of eIF-4E and its purification procedure using the m7GTP affinity chromatography were accomplished. It was shown by spectroscopic methods that the recombinant eIF-4E exhibits essentially the same tertiary structure as the native one and the binding ability with mRNA cap analog was identical with each other. In order to analyze the functional amino acid residues which are essential for specific recognition of mRNA cap structure, next a series of eIF-4E mutants were prepared by the site-directed mutagenesis, and His37, His200, Trp102 and Glu103 were suggested to be important for binding of mRNA cap structure, as judged from comparison of the binding abilities of respective mutants with a m7GTP affinity column. Since the crystals of recombinant eIF-4E-m7GTP complex suitable for X-ray crystallography are now in preparation, the detailed interaction mode between them will be opened in near future.

Amino Acid Sequence↗
PubMed1995

[Screening of phagocyte activators in plants; enhancement of TNF production by flavonoids].

The tumor necrosis factor (TNF) was first discovered as a substance that induced necrosis of transplanted tumors. Recently, TNF has been recognized as an important and endogenous mediator in host defense mechanisms. To prove the fact that plant foods contain substances which activate the host defense mechanisms, we first examined if the administration of flavonoids could induce TNF production in mice. Some selected flavonoids such as naringin, apiin, poncirin and rutin were shown to amplify TNF release from murine macrophages in vivo in response to OK-432 as a second stimulus. However, their aglycone forms were not effective. The differences in the saccharide-chain of flavonoids induced the variety of TNF production.

Animals↗
PubMed1995

A catechol 2,3-dioxygenase gene as a reporter.

A catechol 2,3-dioxygenase (C23O) gene of Pseudomonas aeruginosa was expressed under the Simian virus 40 or Rous sarcoma virus promoter in mammalian cells; it was found that the gene could be used as a reporter for the study of gene expression. The C23O gene was a more sensitive reporter than the generally used beta-galactosidase gene.

Amino Acid Sequence↗
PubMed1995

Insulin receptor gene polymorphism and hyperinsulinemia in hypertensive patients.

Although insulin resistance often occurs in association with hypertension, considerable variation is observed in the degree of insulin resistance among hypertensive patients. Since there is evidence of a genetic basis in the development of insulin resistance in hypertension, we analyzed the contribution of genetic factors to insulin resistance in hypertensive patients. Sixty-six Japanese hypertensive patients were studied. These patients were divided into two groups (hyperinsulinemia group and normoinsulinemia group) according to plasma insulin response during a 75-g oral glucose tolerance test (75g-OGTT). Insulin receptor gene (INSR) was studied for association with insulin resistance in hypertensive patients. A microsatellite polymorphism in intron-2 of the insulin receptor gene was analyzed by the polymerase chain reaction method. Five alleles were detected in the INSR microsatellite. The frequency of C/C genotype in the hyperinsulinemia group was significantly higher than that in the normoinsulinemia group (73% vs. 43%, p = 0.02). There was no difference in genotype frequency of INSR between hypertensive patients and control subjects. When the hypertensive patients were divided into two groups, the frequency of C/C genotype in the hyperinsulinemia group was significantly higher than that in the control group (73% vs. 45%, p = 0.014). There was no significant difference between the normoinsulinemia group and control group. These data suggest that the insulin receptor gene may contribute to insulin resistance in hypertensive patients with hyperinsulinemia.

Alleles↗
PubMed1995

Application of DNA fingerprinting with digoxigenated oligonucleotide probe (CAC)5 to analysis of the genetic variation within Taenia taeniaeformis.

DNA from T. taeniaeformis digested with the restriction endonuclease was hybridized with digoxigenated oligonucleotide probe (CAC)5. Metacestode and adult showed same clear multibanding patterns, which were characteristic of multilocus DNA fingerprinting. The fingerprinting patterns were quite different from those of the rodent hosts. Genetic variations in 4 laboratory-reared isolates of T. taeniaeformis, including 3 isolates which have been reported to be indistinguishable by infectivity, morphology and protein composition of metacestode, were investigated using this technique. Each of the 4 isolates exhibited isolate-specific fingerprinting patterns and were easily distinguished from one another, thus it was considered that (CAC)5 was a highly resolvable and informative probe for cestodes. However, it was also indicated that (CAC)5 was so sensitive that applying fingerprinting with (CAC)5 to taxonomical or phylogenetic analysis was limited where habitat of the host was restricted to the small area. In comparison to fingerprinting with 32P-labeled (CAC)5, fingerprinting with digoxigenated (CAC)5 represented more and sharper bands. It was considered that a digoxigenated probe was more useful for genetic analysis of cestodes.

Animals↗
PubMed1995

Angiotensin I-converting enzyme gene polymorphism is associated with myocardial infarction, but not with retinopathy or nephropathy, in NIDDM.

OBJECTIVE: To clarify the relationship between the angiotensin I-converting enzyme (ACE) gene polymorphism and diabetic micro- and macroangiopathy in patients with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: We examined 267 NIDDM patients with various stages of diabetic retinopathy, 61 patients with myocardial infarction (MI), and 136 patients without MI. An insertion/deletion polymorphism of the ACE gene was typed by polymerase chain reaction. RESULTS: Although no association was found between ACE gene polymorphism and diabetic retinopathy or nephropathy, this polymorphism was associated with MI in the patients with NIDDM. Homozygotes for the deletion polymorphism (DD genotype) were found more frequently in diabetic patients with MI (31.1%) than in diabetic patients without ischemic heart disease (16.9%), with a relative risk of 2.22 (95% confidence interval 1.11-4.46, P = 0.024). CONCLUSION: These data indicate that ACE gene polymorphism is associated with MI, but not with retinopathy or nephropathy, in patients with NIDDM and suggest that the ACE gene confers susceptibility to diabetic macroangiopathy but not to microangiopathy.

Alleles↗
PubMed1995

Carbohydrate cytochemistry of the endothelium lining the splenic blood vessels in the rat.

In the endothelial cells lining the rat splenic blood vessels, neutral carbohydrates were studied by means of combined periodic acid-thiocarbohydrazide-silver protein (PA-TCH-SP) and alpha-amylase digestion methods. In the endothelial cells lining the central and follicular arteries of the spleen, the neutral glycoconjugate-containing surface coat of the luminal plasma membrane and related pinocytotic invaginations and vesicles in the apical cytoplasm were strikingly distinguished, as compared with those in the cells lining the splenic sinuses. In contrast, cytoplasmic glycogen particles in the sinus endothelial cells were apparently larger in amount than those in the arteriolar endothelial cells. Such cytochemical variations of neutral carbohydrates with the arteriolar and venous vessels of the rat spleen were discussed with special reference to varying cytophysiological functions of the endothelial cells with the different segments of the splenic blood vessels.

Animals↗