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Biomedical subjects

T Katsube

Publications and source records attributed to T Katsube.

At least 73 records · Page 4Linked to original sources
PubMed1993

Human fetal-to-adult globin gene switching in transgenic mice: persistent expression of the G gamma-globin gene in the Japanese HPFH.

We linked a 3.3 kb fragment containing the human gamma-globin gene together with a 5.5 kb fragment containing the human beta-globin gene. This construct was introduced into the germ line of mice. Analysis of the resulting transgenic mice showed that expression of the human gamma- and beta-globin genes were regulated as that of the mouse embryonic and adult globin genes and human gamma-to-beta globin switching was reconstructed in the mice. By replacing the gamma-globin gene in the construct with modified counterparts, this transgenic mouse system enables us to analyze cis-acting elements essential for erythroid-specific and developmental stage-specific expression of the test gene under the condition in which human beta-globin gene expression is regulated. In this system expression of the G gamma-globin gene bearing the point mutation found in a Japanese patient of hereditary persistence of fetal hemoglobin (HPFH) (1) persisted at a equivalent level to beta-globin expression in fetal and adult mice.

Aging↗
PubMed1993

Establishment and characterization of an erythropoietin-dependent subline, UT-7/Epo, derived from human leukemia cell line, UT-7.

UT-7 is a human leukemic cell line capable of growing in interleukin-3 (IL-3), granulocyte/macrophage colony-stimulating factor (GM-CSF), or erythropoietin (Epo) (Komatsu et al, Cancer Res 51:341, 1991). To study the effect of Epo on proliferation and differentiation of UT-7, we maintained the UT-7 cell culture for more than 6 months in the presence of Epo. As a result, a subline, UT-7/Epo, was established. The growth of UT-7/Epo could be supported by Epo but not by GM-CSF or IL-3. UT-7/Epo showed a greater level of heme content and ratio of benzidine-positive staining cells than did UT-7. Butyric acid promoted the synthesis of hemoglobin in UT-7/Epo, but not UT-7. Further, the mRNA concentrations of the c-myb oncogene and GM-CSF receptor beta-subunit were decreased substantially in UT-7/Epo cells. These findings showed that UT-7/Epo cells had progressed further in erythroid development than UT-7 cells, and suggested that long-term culture in Epo had promoted this differentiation. Whereas availability of the Epo receptor (Epo-R) for binding of Epo was reduced in UT-7/Epo cells compared with UT-7 cells, the Epo-R showed a similar affinity for Epo. This observation suggested that change(s) in postreceptor signaling step might be involved in the establishment and maintenance of the UT-7/Epo phenotype.

Butyrates↗
PubMed1993

The presence of a common antigen between human gastric cancer cells and OK-432.

Twenty two surgical specimens of gastric cancer resected after administration of OK-432 for the skin reaction test were examined to determine whether the cancer cells had the same antigens as OK-432, a product of hemolytic streptococcus cells. When the tissues were stained by the PAP method with anti-Su streptococcus antibody used as the primary antibodies, the common antigens were demonstrated in 10 (45.5%) of the 22. The presence or absence of the common antigens was independent of the degree of skin reaction to OK-432, and the relations of the common antigens to other host responses were not clear in this study. This is the first report for the presence of such common antigens between human gastric cancer and OK-432.

Adult↗
PubMed1993

Exploring the active site in UDP-glucose pyrophosphorylase by affinity labelling and site-directed mutagenesis.

UDP-glucose pyrophosphorylase catalyses the reversible uridylyl transfer from UDP-glucose to MgPPi, forming glucose 1-phosphate and MgUTP. We have identified, by using uridine di- and tri-phosphopyridoxals, five lysyl residues located at or near the UDP-glucose-binding site. Another reactive analogue, pyridoxal diphosphoglucose, also modified the same set of lysyl residues. Based on the amounts of labels incorporated into each lysyl residue, we have provided a hypothetical model for possible locations of the five lysyl residues around the substrates bound to the enzyme. This model was consistent with the results of the mutagenesis studies. Lys367 is essential for the catalysis, whereas Lys263 may participate in the binding of PPi and/or glucose 1-phosphate in the binary complex. On the other hand, the results of affinity labelling with pyridoxal 5'-diphosphate suggest the role of Lys329 in the direct interaction with PPi in the enzyme-UDP-glucose complex.

Affinity Labels↗
PubMed1992

A single amino acid substitution (Met786----Val) in the steroid-binding domain of human androgen receptor leads to complete androgen insensitivity syndrome.

Androgen receptors (ARs) in two Japanese siblings with complete androgen insensitivity syndrome were characterized, and their molecular bases were investigated. Androgen binding was undetectable in cultured pubic skin fibroblasts from the patients by whole cell assay. Sequence analysis of exons B-H, which encode the DNA- and steroid-binding domains, of the AR gene from these patients using polymerase chain reaction revealed a single nucleotide substitution in exon F, resulting in an amino acid change at 786 from methionine (ATG) to valine (GTG) within the steroid-binding domain of AR. Reconstruction of this mutation by site-directed mutagenesis into human AR cDNA followed by expression in COS-1 cells led to production of the same amount and the same molecular mass of immunodetectable AR protein as those found with expression of the normal human AR cDNA. However, in contrast to wild-type AR expressed in COS-1 cells, the mutant AR showed markedly low affinity of androgen binding by whole cell assay. These results suggest that androgen resistance in these patients is due to the point mutation in the steroid-binding domain of the AR.

Adult↗
PubMed1991

Expression in Escherichia coli of UDP-glucose pyrophosphorylase cDNA from potato tuber and functional assessment of the five lysyl residues located at the substrate-binding site.

The entire structural gene for potato tuber UDP-glucose pyrophosphorylase has been amplified from its cDNA by the polymerase chain reaction and inserted into the expression plasmid pTV118-N downstream from the lac promoter. Escherichia coli JM105 cells carrying thus constructed plasmid produced the enzyme to a level of about 5% of the total soluble protein upon induction with isopropyl beta-D-thiogalactopyranoside. The recombinant enzyme purified to homogeneity in two column chromatographic steps was structurally and catalytically identical with the enzyme purified from potato tuber except for the absence of an N-terminal-blocking acetyl group. To examine functional roles of the five lysyl residues that had been identified by affinity labeling studies to be located at or near the active site of the enzyme [Kazuta, Y., Omura, Y., Tagaya, M., Nakano, K., & Fukui, T. (1991) Biochemistry (preceding paper in this issue)], they were replaced individually by glutamine via site-directed mutagenesis. The Lys-367----Gln mutant enzyme was almost completely inactive, and the Lys-263----Gln mutant enzyme had significantly decreased Vmax values with perturbed Km values for pyrophosphate and alpha-D-glucose 1-phosphate. Lys-329----Gln also exhibited increased Km values for these substrates but exhibited Vmax values similar to those of the wild-type enzyme. The two mutant enzymes Lys-409----Gln and Lys-410----Gln showed catalytic properties almost identical with those of the wild-type enzyme. Thus, among the five lysyl residues, Lys-367 is essential for catalytic activity of the enzyme and Lys-263 and Lys-329 may participate in binding of pyrophosphate and/or alpha-D-glucose 1-phosphate.

Amino Acid Sequence↗
PubMed1991

Exonic point mutations in NADH-cytochrome B5 reductase genes of homozygotes for hereditary methemoglobinemia, types I and III: putative mechanisms of tissue-dependent enzyme deficiency.

We analyzed the NADH-cytochrome b5 reductase gene of hereditary methemoglobinemia type I and type III, by using PCR-related techniques. The mutation in type I is a guanine-to-adenine substitution in codon 57 of exon 3 of the NADH-cytochrome b5 reductase gene, and the sense of this codon is changed from arginine to glutamine. In type III the mutation is a thymine-to-cytosine transition in codon 148 of exon 5, causing leucine-to-proline replacement in type III. The former mutation abolishes the MspI recognition site. Homozygosity for the former mutation in a patient with type I was confirmed by restriction analysis of PCR-amplified fragments and by dot blot hybridization of amplified products with allele-specific oligonucleotide probes. The latter mutation generates a recognition site for MspI. Amplification of exon 5 by PCR followed by digestion with MspI revealed homozygosity for this mutation in patients with type-III. Putative mechanisms of tissue-dependent enzyme defects in hereditary methemoglobinemia are discussed.

Adult↗
PubMed1990

UDP-glucose pyrophosphorylase from potato tuber: cDNA cloning and sequencing.

We have isolated a cDNA encoding UDP-glucose pyrophosphorylase from a cDNA library of immature potato tuber using oligonucleotide probes synthesized on the basis of partial amino acid sequences of the enzyme. The cDNA clone contained a 1,758-base-pair insert including the complete message for UDP-glucose pyrophosphorylase with 1,431 base pairs. The amino acid sequence of the enzyme inferred from the nucleotide sequence consists of 477 amino acid residues. All the partial amino acid sequences determined protein-chemically [Nakano et al. (1989) J. Biochem. 106, 528-532] confirmed the primary structure of the enzyme. An N-terminal-blocked peptide was isolated from the proteolytic digest of the enzyme protein, and the blocking group was deduced to be an acetyl group by fast atom bombardment-mass spectrometry. On the basis of the predicted amino acid sequence (477 residues minus the N-terminal Met plus an acetyl group), the molecular weight of the enzyme monomer is calculated to be 51,783, which agrees well with the value determined by polyacrylamide gel electrophoresis. In the cDNA structure, the open-reading frame is preceded by a 125-base-pair noncoding region, which contains a sequence being homologous with the consensus sequence for plant genes, and is followed by a 174-base-pair noncoding sequence including a polyadenylation signal. Amino acid sequence comparisons revealed that the potato UDP-glucose pyrophosphorylase is homologous to the enzyme from slime mold, Dictyostelium discoideum, but not to ADP-glucose pyrophosphorylases from rice seed and Escherichia coli.

Amino Acid Sequence↗
PubMed1990

Molecular heterogeneity of beta-thalassaemia in the Japanese: identification of two novel mutations.

Five unrelated Japanese beta-thalassaemia genes, from one homozygote and four heterozygotes, have been systematically characterized using DNA polymorphism analysis, polymerase chain reaction, dot-blot hybridization and direct sequencing of amplified genomic DNA. Four different molecular defects were observed on three different beta-globin gene frameworks. One of these, the A----G mutation in the TATA box, a previously described mutation, was detected by dot-blot hybridization in one homozygote and one heterozygote with the beta-globin gene of framework 2. The second mutation is a C----T substitution at position 654 of IVS-2, the mutation commonly found in Chinese, which was associated with the framework 1 gene. Another two mutations, both associated with framework 3 genes, are novel ones; an amber mutation in codon 90 (GAG to TAG) and a frameshift (+G) insertion in codon 54, both of which cause a beta 0-thalassaemia phenotype by premature termination of the beta-globin chain synthesis.

Adult↗
PubMed1990

Abnormally distributed branches of the retinal vessels, enlarged macular arteries and long cilioretinal arteries.

We examined fundus photographs of 3,506 eyes and noted uncommon retinal vessel patterns in the temporal quadrants of the posterior fundus. Of 1,753 subjects, 20 patients (21 eyes) had unusual retinal vessel patterns. Seven eyes had an abnormally distributed branch of the inferotemporal artery; 8 eyes had an enlarged macular artery. Of these 20 patients, 1 had visual complaints associated with the unusual vascular patterns.

Adult↗
PubMed1988

Leber's miliary aneurysms in a 63-year-old woman: concurrence of regression and active lesions.

We examined a 63-year-old woman with retinal telangiectasia, aneurysms, a ring of fatty exudate, and pigmented chorioretinal atrophic lesions in the right eye. Leber's miliary aneurysm was diagnosed, although this disorder is known to have a high incidence mainly in young boys. The pigmented chorioretinal scars appear to be sequelae of spontaneously regressing retinal lesions.

Aneurysm↗
PubMed1987

Self-rating depression scales correlated with regional cerebral blood flow in normal volunteers.

In order to investigate possible influences of satisfaction with life on regional cerebral blood flow (rCBF), we studied the relationship between the self-rating depression scale and rCBF in normal middle-aged volunteers. A significant inverse correlation between SDS scores and the rCBF was observed. This result was independent of the influences of risk factors for stroke and age. Our findings suggest that satisfaction in daily life is important in maintaining active levels of brain metabolism.

Adult↗
PubMed1985

Long-term effect of cilostazol on cerebral blood flow in chronic cerebral infarction.

The effect of the oral administration of a new vasodilator, cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy]-3,4-dihydro-2(1H)-quinolinone, OPC-13013) on cerebral circulation in chronic cerebral infarction was studied by the 133Xenon inhalation method. Mean regional cerebral blood flow (rCBF) was increased in 6 out of 14 cases after 2 weeks of treatment. Hemispheric rCBF was significantly increased in both the affected and non-affected sides (10.8 and 13.4%, respectively) (p less than 0.05) without causing a change in blood pressure.

Aged↗
PubMed1984

Dysautoregulation of the cerebral circulation in primary systemic amyloidosis.

A case of primary systemic amyloidosis associated with marked dysautoregulation of the cerebral circulation in response to hypotension is reported. The major amyloid protein was immunoglobulin A lambda type. An autonomic nerve function test showed severe and extensive disturbances of the autonomic nervous system. The cerebrovascular reactivity to 5% CO2 inhalation was spared. To our knowledge, this is the first case to demonstrate that amyloid peripheral autonomic neuropathy can be accompanied by dysautoregulation of the cerebral circulation.

Amyloidosis↗