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H Uchida

Publications and source records attributed to H Uchida.

At least 181 records · Page 10Linked to original sources
PubMed1997

Interindividual variation in cytogenetic response to X-ray and colchicine measured with the cytokinesis-block micronucleus assay.

Interindividual variation in cytogenetic response to two different types of micronucleus (MN) inducer, X-rays (a clastogen) and colchicine (a spindle poison), was investigated in the peripheral blood lymphocytes of normal healthy donors by the cytokinesis-block MN method. The data for 124 donors between the ages of 19 and 80 years showed that the histogram of individual frequency of X-ray (2 Gy)-induced micronucleated cells followed the normal distribution (Shapiro Wilks W-test) with a significant interindividual variance (ANOVA, p < 0.001). This was, however, not the case for colchicine (0.03 microgram/ml)-induced micronucleated cells. Instead, a skewed distribution illustrating interindividual variation was evident (ANOVA, p < 0.001). Statistical analysis of the effect of age and sex on MN incidence by using the Kruskal-Wallis test indicated that age affected the baseline and colchicine-induced MN incidences strongly but not the X-ray-induced MN incidence. There was no effect of sex on the incidence of micronuclei induced by either agent. In order to avoid any possible effect of age on the MN index, data for young subjects aged less than 30 years old were analyzed separately. The results of this analysis again showed significant interindividual variations in baseline, X-ray-induced, and colchicine-induced micronucleated cell rates. Results of the correlation-coefficient analysis showed that neither X-ray-induced MN incidence nor colchicine-induced MN incidence was related to baseline MN incidence. No correlation between X-ray-induced and colchicine-induced MN incidences was also found by this analysis. These results suggest that interindividual variance in chromosomal response to mutagens in normal populations may be a real phenomenon, as is interindividual variance in baseline MN frequency, and that individual susceptibilities to the two different types of micronucleus inducers (X-ray and colchicine) are unrelated, and the baseline MN level is not of predictive value for the susceptibilities.

Adult↗
PubMed1997

Phosphodiester amidates of unsaturated nucleoside analogues: synthesis and anti-HIV activity.

The effect of introduction of a lipophilic phosphodiester amidate moiety on the HIV activity of inactive unsaturated nucleoside analogues was investigated. Phosphodiester alaninates 5a, 5b, and 6 derived from unsaturated nucleoside analogues 3b, 3c, and 4a were synthesized and investigated as inhibitors of cytopathic effect and replication of HIV-1 in ATH-8 cells. Compound 5a is an inhibitor of HIV-1 whereas analogue 6 is inactive with cytotoxicity appearing above 10 microM and 5b is both inactive and nontoxic. Alkaline or enzymic hydrolysis of 5a gave phosphomonoester alaninate 14, a putative product of intracellular metabolism. Compound 14 as well as adenallene derivative 15c were devoid of anti-HIV activity, and they also failed to inhibit HIV reverse transcriptase. A new regioselective method for preparation of (Z)-4-(benzoyloxy)-1-hydroxy-2-butene, 7, a key intermediate for the synthesis of unsaturated nucleoside analogues of cis configuration such as 3a, 3b, and 3c, is also described.

Animals↗
PubMed1997

Secretion of authentic 20-kDa human growth hormone (20K hGH) in Escherichia coli and properties of the purified product.

Using Bacillus amyloliquefaciens neutral protease gene (npr), we have constructed a secretion system of 20-kDA human growth hormone (20K hGH) in E. coli. The secretion-signal region from npr was modified inserting a fragment coding a 2Lys-5Leu cluster. In this system we found that co-expression of glutathione reductase remarkably increased accumulation level of 20K hGH in periplasm and confirmed that secreted 20K hGH was correctly processed. The recombinant 20K hGH was highly purified and subjected to analyses of physicochemical properties and biological activities which are still unclear and controversial due to difficulty in preparing the sample with authentic structure. The secreted recombinant product had authentic disulfide linkages and showed molecular weight of 20,270.5 +/- 3.7 (theoretical value, 20,269.9). The results suggest that the recombinant 20K hGH is a full agonist on rat growth promotion and lipolysis stimulation in isolated rat adipose tissues. In particular, the lipolysis-stimulating activity of 20K hGH was distinct as compared with that of 22K hGH under physiological concentration. Cell proliferation activity via prolactin-receptor in Nb-2 lymphoma was obviously low as compared with that of 22K hGH.

Amino Acid Sequence↗
PubMed1997

AML1A and AML1B can transactivate the human IL-3 promoter.

The AML1 gene encodes several transcription factors, including AML1A and AML1B, which bind to DNA via a TGT/cGGT consensus sequence that is found in several promoters, including the human IL-3 promoter. We performed cotransfection experiments in T cells, and demonstrated that although AML1A lacks a putative transactivation domain, it can transactivate the IL-3 promoter nearly as effectively as AML1B, a known activator. A consensus AML1 binding site (TGTGGT), located in the previously identified DNase I footprint region A of the human IL-3 promoter (extending from bp -165 to -128), and a sequence similar to the consensus binding site (TGTGGG), located in footprint region B (bp -55 to -42), specifically bind AML1 proteins in gel shift assays. The affinity for the TGTGGG sequence was much less than that for the TGTGGT sequence, and mutating the TGTGGG sequence did not alter the IL-3 promoter activity, whereas mutation of the consensus binding site decreased the basal promoter activity and nearly eliminated transactivation by AML1A and AML1B. The AML1/ETO fusion protein, generated by the t(8;21) translocation, repressed IL-3 promoter activity, although the AML1 portion of AML1/ETO (amino acids 1-177) lacked transcriptional regulatory activity and did not bind to DNA in vitro. The 60- to 177-amino acid portion of AML1 readily bound DNA, suggesting that the first 59 amino acids may function as an inhibitory domain for DNA binding. Demonstration of the transactivation by AML1A and localization of a putative inhibitory binding domain suggest additional complexity within this family of transcription factors.

Amino Acid Sequence↗
PubMed1997

Cyclic thrombocytopenia in a patient treated with cyclosporine for refractory idiopathic thrombocytopenic purpura.

Cyclic thrombocytopenia (CT) is a rare disorder with cyclic changes of the platelet counts. Though the pathogenesis of this disorder has not been clarified, recent reports suggest that periodic destruction and/or ineffective production of platelets may be important causes of the disease. We report a case of a patient with refractory idiopathic thrombocytopenic purpura (ITP) in whom CT developed after cyclosporine A (CyA) therapy. There was an inverse relation between platelet counts and the serum levels of platelet-associated immunoglobulin G (PAIgG). The ploidy of bone marrow megakaryocytes also had an inverse relation with platelet counts. When the platelet count was low, the ploidy of megakaryocytes increased (P < 0.01). The number and area of bone marrow megakaryocytes were unrelated to platelet counts. These results indicate the possibility of platelet destruction caused by immunological mechanisms in CT. Cyclosporine A could have certain but fluctuating regulatory effects against antibody production for circulating platelets, which could lead to cyclic changes of the platelet counts. This case also suggests that CyA can be effective in severe refractory ITP. Regulatory mechanisms of platelet production and destruction and appropriate doses of CyA should be further studied in autoimmune-mediated thrombocytopenias.

Adult↗
PubMed1997

A nonspecific colonic ulcer occurring after hepatectomy: report of a case.

We herein report the case of a 53-year-old man with a nonspecific acute colonic ulcer whose liver function deteriorated after he had undergone hepatectomy. He was referred to our hospital for a hepatoma caused by hepatitis B virus and a right hemihepatectomy was performed. His liver function was poor after the operation, and minor complications such as pleural effusion and biliary fistula developed. A large amount of melena was seen 29 days after the hepatectomy and he developed hemorrhagic shock. Superior mesenteric arteriography revealed pooling of blood in both the hepatic flexure of the ascending colon and the cecum. An emergency right hemicolectomy was performed. There was a 5 x 1-mm ulcer 18 cm distal to the ileocecal valve. Numerous erosions were observed to be scattered throughout the colonic mucosa. The patient recovered slowly and was discharged 6 months after the hepatectomy. This is the first report of an acute colonic ulcer that could have been caused by liver dysfunction.

Carcinoma, Hepatocellular↗
PubMed1997

Stability of microcystins from cyanobacteria--IV. Effect of chlorination on decomposition.

Microcystins, the cyclic heptapeptide toxins produced by cyanobacteria such as Microcystis, show tumor-promoting activity through inhibition of protein phosphatases 1 and 2A. They potentially threaten human health, and are increasing the world-wide interest in the health risk associated with cyanobacterial toxins. In this study, the effect of chlorination on the decomposition of microcystins-LR and -RR was examined. The toxins were easily decomposed by chlorination with sodium hypochlorite, and the decomposition depended on the free chlorine dose. In this operation, many reaction products were formed, one of which was determined to be dihydroxymicrocystin formed through the chloronium ion at the conjugated diene of Adda [3-amino-9-methoxy-10-phenyl-2,6,8-trimethyl-deca-4(E), 6(E)-dienoic acid], followed by hydrolysis. Other products may be its stereoisomers and/or regioismers. No noxious products were detected from the chlorination process of microcystin-LR. Although these results suggested that chlorination at an adequate chlorine dose is very effective for the removal of microcystin in raw water, preoxidation of the cell itself with chlorine must be avoided, because it frequently causes toxin release from algae and produce trihalomethanes during water treatment.

Animals↗
PubMed1997

Analysis of oil components and hydrocarbon-utilizing microorganisms during laboratory-scale bioremediation of oil-contaminated soil of Kuwait.

A huge amount of oil-contaminated soil remains unremediated in the Kuwait desert. The contaminated oil has the potentiality to cause pollution of underground water and to effect the health of people in the neighborhood. We have been studying bioremediation of Kuwait oil-contaminated soil. Chemical analyses of biodegraded compounds and isolation of petroleum hydrocarbon-decomposing microorganisms were carried out. From the chemical analyses, it was revealed that the decomposed compounds were mainly saturated fractions from alumina column chromatography and that the aromatic fractions were not decomposed well. Isolation of bacteria was carried out for eight kinds of hydrocarbons which are components of crude petroleum (n-hexadecane, 2,6,10,14-tetramethylpentadecane, 1,4-diisopropylbenzene, naphthalene, 1-methylnaphthalene, phenanthrene, anthracene, and perylene). Many of the n-hexadecane- and 2,6,10,14-tetramethylpentadecane-decomposing bacteria were isolated, but aromatic compound-decomposing bacteria were not enriched. It was concluded that the slow decomposition of aromatic compounds was due to the low population of aromatic compound-decomposing bacteria in the Kuwait desert soil.

Bacteria↗
PubMed1997

HIV-1 protease does not play a critical role in the early stages of HIV-1 infection.

We asked whether human immunodeficiency virus type 1 (HIV-1) protease plays a major role in the early stages of infection (i.e. from viral entry to reverse transcription) by using various protease inhibitors (saquinavir, ritonavir, and KNI-272). When assessed in the two-day multinuclear activation of a galactosidase indicator (MAGI) assay, involving a single cycle of HIV-1 replication, all protease inhibitors failed to block infection of HeLa-CD4-LTR-beta-gal cells by HIV-1, while reverse transcriptase (RT) inhibitors (AZT and ddI) completely blocked the infection. Moreover, when HIV-1 proviral DNA synthesis was examined by polymerase chain reaction in HeLa-CD4-LTR-beta-gal cells exposed to HIV-1 and cultured in the presence of protease inhibitors, a significant amount of proviral DNA was detected, while no proviral DNA synthesis was detected when the cells were cultured in the presence of RT inhibitors. Protease inhibitors also failed to block chloramphenicol acetyltransferase (CAT) expression in HLCD4-CAT cells exposed to HIV-1, while RT inhibitors completely suppressed CAT expression. These results strongly suggest, contrary to a previous report by Nagy et al. (1994), that HIV-1 protease does not play a major role in the early stages of infection.

Chloramphenicol O-Acetyltransferase↗
PubMed1997

Hyporesponsiveness of inflamed human gingival fibroblasts from patients with chronic periodontal diseases against cell surface components of Porphyromonas gingivalis.

Inflamed human gingival fibroblasts (HGF) of patients with chronic periodontal diseases have less active interleukin-8 (IL-8) production compared with normal HGF of volunteers with healthy gingival tissues, after stimulation with Porphyromonas gingivalis surface components such as fimbriae, lipopolysaccharide (LPS) and its lipid A, but not LPS or lipid A from other bacterial species. A decrease in number of specific binding sites for P. gingivalis fimbrial molecules in inflamed HGF is also observed by Scatchard plot analysis. A short exposure (6 h) to P. gingivalis LPS resulted in significant potentiation of the LPS-dependent IL-8 production in normal HGF, whereas a long exposure (48 h) to the LPS significantly reduced IL-8 production. Tyrosine phosphorylation of proteins of 127 kDa and 186 kDa in inflamed HGF stimulated with P. gingivalis fimbriae or its LPS was observed by immunoblotting, and these two phosphoproteins were termed tolerance-induced protein, TIP. Protein bands of 45 kDa which bound to radioiodinated P. gingivalis fimbriae in the presence and absence of fetal bovine serum (FBS), and major 73-kDa and minor 30-kDa and 45-kDa bands which bound to radioiodinated P. gingivalis LPS in the presence of FBS in normal and inflamed HGF were observed by using photocrosslinking. These findings suggest that the hyporesponsiveness of HGF induced by a prolonged exposure to P. gingivalis may emerge because of HGF damage or result from host defense in chronic periodontal lesions.

Adult↗
PubMed1997

Probing interactions between viral DNA and human immunodeficiency virus type 1 integrase using dinucleotides.

Retroviral integrases are essential for viral replication and represent an attractive chemotherapeutic target. In the current study, we demonstrated the activity of micromolar concentrations of dinucleotides against human immunodeficiency virus type 1 (HIV-1), HIV type 2 (HIV-2), simian immunodeficiency virus, and feline immunodeficiency virus integrases. The structure-activity relationship indicates that 5'-phosphorylation enhances potency and that phosphodiester and sugar modifications affect the inhibition of HIV-1 integrase. Base sequence selectivity was observed: pAC, pAT, and pCT were the most potent inhibitors, whereas pAA, pGA, and pGC showed low activity at 100 microM. The inhibition by pAC is consistent with the interaction of the enzyme with the 5' end of the noncleaved strand (5'-AC-3'). The linear and cyclic dinucleotides released by the 3'-processing reaction did not affect enzymatic activity at physiological concentrations. An increase in the length to trinucleotides or tetranucleotides enhanced potency by only 2-3-fold, suggesting that two neighboring bases may be sufficient for significant interactions. Inhibition of a truncated (50-212) integrase mutant and global inhibition of all nucleophiles in the 3'-processing reaction suggest that dinucleotides bind in the catalytic core. All of the active dinucleotides inhibited enzyme/DNA binding in their respective IC50 range. Although the dinucleotides tested showed no antiviral activity, these observations demonstrate the usefulness of dinucleotides in elucidating enzyme mechanisms and as potential ligands for cocrystallization and as lead structures for development of antivirals.

Animals↗
PubMed1997

MR cholangiopancreatography and MR urography: improved enhancement with a negative oral contrast agent.

At magnetic resonance (MR) cholangiopancreatography and MR urography with an oral negative contrast agent, low signal intensity was produced in phantoms. In 20 patients suspected of having biliary tract and pancreatic diseases and in 20 healthy volunteers, the signal intensity in the gastrointestinal tract was almost completely eliminated with the negative contrast agent. Differences in image quality between pre- and postcontrast images were statistically significant.

Administration, Oral↗
PubMed1997

Pancreatitis: evaluation with MR cholangiopancreatography in children.

PURPOSE: To determine the usefulness of magnetic resonance (MR) cholangiopancreatography in assessing the cause of pancreatitis in children. MATERIALS AND METHODS: Twenty healthy volunteers (aged 2-11 years) and 10 patients with acute pancreatitis (aged 3-12 years) who underwent MR cholangiopancreatography between December 1993 and February 1996 were studied retrospectively. The rate of visualization of the common bile duct and main pancreatic duct with MR cholangiopancreatography was assessed in the volunteer group. Depiction of pancreaticobiliary disease at MR cholangiopancreatography was assessed in the patient group. RESULTS: MR cholangiopancreatography clearly showed the common bile duct in 20 of 20 volunteers (100%) and the main pancreatic duct in 13 of 20 volunteers (65%). MR cholangiopancreatography depicted a dilated common bile duct in six of 10 patients (60%) and an abnormal arrangement of the pancreaticobiliary duct in five of the six patients (83%) in whom this structural abnormality was proved at surgery. In the four patients without structural abnormality, MR cholangiopancreatography depicted a pseudocyst in one patient who had traumatic pancreatitis; the other three patients had normal findings. In one of these three patients, familial pancreatitis was considered to be the underlying disorder, and in the other two patients no cause was identified. CONCLUSION: MR cholangiopancreatography may be helpful in diagnosing the cause of pancreatitis in children, especially in those with an abnormal pancreaticobiliary ductal junction.

Acute Disease↗
PubMed1997

Expression of LH-alpha and -beta subunit mRNAs in the rat placenta.

Gonadotropic activity is present in the placenta of various mammals including humans. Human and equine chorionic gonadotropin (CG) are well characterized and known to be glycoprotein hormones, as are pituitary LH, TSH and FSH. In the rat, however, the placental gonadotropin molecule has not been identified, and in fact the existence of CG in the rodent is still controversial. In the present study, the placental expression of mRNA for CG-like molecules was investigated by PCR with mixed primers designed for the CG-beta subunit based on the amino acid sequences common to the rat LH-beta, human LH-beta, equine LH-beta and human CG-beta subunits and for the alpha subunit designed from the rat LH-alpha subunit. PCR with mRNA extracted from the placenta (day 10 of pregnancy) amplified several bands including cDNA identical to part of rat LH-alpha and -beta. Furthermore, expression of these genes was confirmed in the placenta on days 10, 12, 14, 16, 18 and 20 of pregnancy by PCR with another set of primers specific to rat LH-alpha and -beta and by Southern hybridization with 32P-labeled cDNAs for LH-alpha and -beta. The specific bands for these subunit mRNAs were amplified in the placenta, as well as in the positive control i.e. the anterior pituitary gland, but were not detected in other tissues including decidual tissue, liver, spleen, intestine, brain and kidney. Expression of the mRNAs was observed in both the junctional and labyrinth zones of the placental tissue. The rat choriocarcinoma cell line Rcho-1 also expressed LH-alpha but not LH-beta regardless of the stage of differentiation in vitro. Here we show the expression of LH-alpha and -beta mRNAs in the rat placenta.

Amino Acid Sequence↗
PubMed1997

Intrathecal oxygen concentration as a new indicator of spinal cord ischemia.

A number of approaches have been put forward to monitor spinal cord ischemia during thoracic and thoracoabdominal aortic occlusion. However, none of these can ultimately prevent devastating complications which result from ischemic spinal cord injury. A direct measurement of the oxygen content of the spinal cord may accurately indicate the perfusion state, but in practice it is impractical. We surmised that intrathecal and/ or epidural oxygen concentration(I-pO2 and E-pO2, respectively) accurately reflect oxygen content in the spinal cord. So, we examined whether or not I-pO2 and/or E-pO2 correlated with the spinal cord pO2 (S-pO2) in dogs. In nine mongrel dogs, a model of graded spinal cord ischemia was developed by stepwise alternation of the level of aortic occlusion with an intraaortic balloon catheter. I-pO2, E-pO2 and S-pO2 were measured with a mass spectrometer. Our results show that, both I-pO2 and E-pO2 significantly correlated with S-pO2. I-pO2 correlated with S-pO2 better than E-pO2 did. Therefore, I-pO2 can be used as a new indicator for spinal cord ischemia, and I-pO2 monitoring would be useful to prevent paraplegia associated with thoracic aortic surgery.

Animals↗
PubMed1997

Effects of spaceflight on enzyme activities and ultrastructure of fast-type skeletal muscles of rats.

The activity of succinate dehydrogenase in the medial gastrocnemius muscles of rats was significantly increased following a 2-week spaceflight (p < 0.05). That of phosphofructokinase in plantaris muscles was lowered after the flight (p < 0.05). The overall activities of both enzymes were effectively maintained during the flight. No structural alterations in the mitochondria or other organelles were observed in response to spaceflight. However, disordering of myofilament and central nucleus were often seen in the fast muscle during recovery after landing, but not immediately after landing. These observations indicate that spaceflight increases susceptibility to sarcomere damage and metabolic activity in a specific muscle during reloading.

Animals↗