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Biomedical subjects

T Horiuchi

Publications and source records attributed to T Horiuchi.

At least 271 records · Page 15Linked to original sources
PubMed1995

IL-4 stimulates the growth of chronic myelomonocytic leukemia cells (CMMoL) once leukemic transformation has occurred.

We have investigated the effects of interleukin-4 (IL-4) on the proliferation of chronic myelomonocytic leukemia (CMMoL) cells in the chronic and leukemic transformation phases in vitro. CMMoL cells formed colonies spontaneously in both phases. IL-4 suppressed the spontaneous growth in the chronic phase, but on the other hand, stimulated colony formation in the leukemic transformation phase. Anti-IL-6 antibody inhibited spontaneous colony formation in both phases. CMMoL cells in both phases produced high levels of IL-6, compared with those produced by acute myelogenous leukemia (AML) cells showing myelomonocytic differentiation and normal monocytes. IL-4 suppressed the IL-6 production by CMMoL cells in both phases. None of anti-IL-6, anti-macrophage colony-stimulating factor (M-CSF), anti-granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-tumor necrosis factor-alpha (TNF-alpha) and anti-IL-1-beta antibodies inhibited IL-4-stimulated colony formation. These results suggest that IL-4 directly stimulates the growth of CMMoL cells once leukemic transformation has occurred and that the therapeutic use of IL-4 for CMMoL should be viewed with caution, especially in the leukemic transformation phase.

Aged↗
PubMed1995

[The metabolic mode of circulating parathyroid hormone].

The circulating immunoreactive parathyroid hormone (PTH) exists in more than one form in plasma. These immunoreactive forms of PTH consists of intact hormone (large molecular weights) and lower molecular weight hormonal fragments from both the carboxyterminal and aminoterminal portions of PTH molecules. The most of the secreted intact PTH is cleaved or degraded in kidney and liver with forming C-terminal PTH. A little amounts of PTH are metabolized in bone or in other tissues bearing PTH/PTHrP receptor. This chapter reviews the mode of PTH metabolism in the peripheral tissues.

Animals↗
PubMed1995

[CD5-negative B-cell chronic lymphocytic leukemia (B-CLL) associated with massive splenomegaly and without lymphadenopathy].

A 39-year-old male was referred to our hospital in June, 1993, because of leukocytosis. Physical examinations showed massive splenomegaly without any lymphadenopathy. The white blood cell count was 13,800/microliters with 87% morphologically mature lymphocytes. Bone marrow aspirate revealed hypercellularity with 67% lymphocytes morphologically similar to peripheral lymphocytes. The lymphocytes displayed monoclonal rearrangements of immunoglobulin genes and the phenotype of CD5-CD19+CD20+ CD21+ and Smlg+. Splenectomy was effective against neutropenia and thromboytopenia. The clinical and laboratory findings of this case were unusual compared to those of typical B-CLL in massive splenomegaly, no lymphadenopathy and CD5-phenotype, suggesting the heterogeneity of B-CLL.

Adult↗
PubMed1995

[Pulmonary involvement in immunoblastic lymphadenopathy: case reports and review of literature published in Japan].

To investigate pulmonary involvement in immunoblastic lymphadenopathy (IBL), we report five cases of IBL and 21 other reports from the literature published in Japan. Three of the present patients had respiratory symptoms and showed hypoxemia on admission. Radiographic findings in the present cases showed bilateral mediastinal and hilar lymphadenopathy (LA: 4/5), pleural effusion (PE: 5/5), interstitial shadow (Int S: 1/5), alveolar shadow (A1S: 2/5), and atelectasis (1/5). In the present cases and those previously reported in Japan, the following radiographic findings were observed; LA (56%), PE (40%), Int S (52%), and A1S (24%). Atelectasis was reported only in the present cases. The nine patients with Int S consisted of four with interstitial pneumonia and five with bronchopneumonia. Four of five patients with bronchopneumonia had an opportunistic infection (three had pneumocystis carinii and one had cytomegalovirus). Among the five patients with A1S, two had interstitial pneumonia and the others had bronchopneumonia. Pulmonary involvement was frequently seen in patients with IBL, and may be an important determinant of the outcome of the disease.

Aged↗
PubMed1994

Heterologous expression of the cytochrome P450cam hydroxylase operon and the repressor gene of Pseudomonas putida in Escherichia coli.

The cytochrome P450cam hydroxylase operon (camDCAB) of Pseudomonas putida is negatively regulated by a repressor, CamR, which also represses its own gene. The expression in P. putida of both camR and camDCAB is derepressed in the presence of D-camphor. We examined the expression in Escherichia coli of camR and camDCAB by monitoring the enzyme activity of the camD gene product. In the presence or absence of D-camphor in the cell culture, the expression in E. coli of camD was significant and constitutive, suggesting no expression of camR. This lack of expression was confirmed by monitoring the beta-galactosidase activity of camR-lacZ translational fusions. However, S1 nuclease mapping revealed that synthesis of camR mRNA in E. coli was significant and constitutive, as observed in the case of camDCAB mRNA. Thus, it is likely that the expression of camR in E. coli is limited at the translational level.

Camphor↗
PubMed1994

Significant contribution of arginine-112 and its positive charge of Pseudomonas putida cytochrome P-450cam in the electron transport from putidaredoxin.

Cytochrome P-450cam of Pseudomonas putida is a prototype of various eukaryotic cytochrome P-450 molecules. Arg-112 located on the surface of this protein is highly conserved among various other cytochromes P-450. In this study, we constructed mutant genes for P-450cam in which Arg-112 was replaced by Gln or Glu, expressed them in Escherichia coli and purified the mutant proteins. Their enzymic activities were analyzed in the reconstituted system to determine the function of Arg-112. Kd values for d-camphor of Arg112-Gln and Arg112-Glu were much the same as those of the wild-type enzyme, whereas Kd values for the oxidized form of putidaredoxin, which is an acidic protein and is the redox partner of P-450cam, were 240 and 530 microM, respectively. These values are 8 and 19 times larger than that of the wild-type enzyme (28 microM), thereby indicating lower affinities of the mutant enzymes for the oxidized putidaredoxin. Reaction rate constants for reduction by the reduced form of putidaredoxin, measured using the stopped flow method, were 45.5, 9.0 x 10(-3) and 9.0 x 10(-4) s-1 for the wild type, Arg112-Gln and Arg112-Glu, respectively. Thus, Arg-112 of P-450cam plays an important role in the interaction with putidaredoxin and in the high efficiency of the electron transfer; the positive charge of the residue seeming to contribute to the process. The yields in Escherichia coli, the heme contents in the purified fractions and heat stability of the mutant proteins were lower than those of the wild type enzyme, suggesting that Arg-112 of P-450cam is also important for stability of P-450cam.

Arginine↗
PubMed1994

Difference in response to colony-stimulating factors and involvement of protein kinase C signal transduction system in three subclones from the ME-1 cell line and two sublines.

We previously established a cell line from a patient with acute myelomonocytic leukemia with eosinophilia (M4E0), ME-1. ME-1 cells are responsive to colony-stimulating factors (CSFs) such as interleukin-3 (IL-3), IL-4, and granulocyte-macrophage CSF (GM-CSF), and exhibit monocyte-macrophage differentiation. We isolated three subclones, ME-F1 from ME-1, and ME-F2 and ME-F3 from two sublines of ME-1. These subclones had different morphologic, cytochemical, phenotypic, and cytogenetic features. They represented different monocytic-lineage differentiation stages and exhibited different responses to IL-3, GM-CSF, and especially IL-4. IL-3, GM-CSF, and IL-4 enhanced proliferation and differentiation to macrophage-like cells in the ME-F1 subclone. However, they enhanced only proliferation of ME-F2 cells and only differentiation to macrophage-like cells in the ME-F3 subclone. To elucidate possible differences in signal transduction mechanisms in ME-F1, ME-F2, and ME-F3 cells following stimulation by CSFs, we studied the effects of IL-3 and IL-4 on protein kinase C (PKC) activity. Both IL-3 and IL-4 induced a rapid, transient decrease of cytosolic PKC in ME-F1 cells, but did not affect PKC activity in ME-F2 and ME-F3 cells. The PKC inhibitors, 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine (H-7) and calphostin C inhibited IL-3-induced enhancement of proliferation and differentiation of ME-F1 cells, but did not inhibit enhancement of proliferation of ME-F2 cells and differentiation of ME-F3 cells. Our data suggest that PKC-dependent signal transduction is considerably related to IL-3-induced proliferation and differentiation of ME-F1 cells. In addition, it was demonstrated that the two subclones, ME-F2 and ME-F3, lost one of the two responses of ME-F1 cells to CSFs, either proliferation or differentiation, and simultaneously lost PKC-dependent response to CSFs.

Cell Differentiation↗
PubMed1994

Occurrence of a P450 showing high homology to yeast lanosterol 14-demethylase (P450(14DM)) in the rat liver.

The rat liver cDNA library in lambda gt11 was screened with the antisera against rat liver lanosterol 14 alpha-demethylase (P450(14DM)), and one clone (pRT-9) was isolated. The open reading frame of pRT-9 cDNA showed high homology to yeast P450(14DM) (48.9% in nucleotides and 37.7% in amino acids). Homology of the heme-binding region of pRT-9 protein to that of yeast P450(14DM) was 80%. Three additional regions showing more than 60% homology were identified and one of them was assignable as the distal helix. These findings suggest that pRT-9 protein is P450(14DM) and P450(14DMs) of rat and yeast may be orthologous. This is the first evidence suggesting the occurrence of orthologous P450 in widely diverged species.

Amino Acid Sequence↗
PubMed1994

Monoclonal proliferation of double-negative (CD4-CD8-) T-cells bearing T-cell receptor-alpha beta followed by subsequent development of Hodgkin's disease.

Expression of CD4 or CD8 on the cell surface is an important guide for discriminating the immunologic functions of T-cells. However, a minor T-cell subset lacking both CD4 and CD8 molecules but bearing the usual form of T-cell receptor (TCR)-alpha beta (CD4-CD8-TCR-alpha beta+ T-cells) has recently been found not only in mice but also in humans, and the clinical relevance of this newly defined subpopulation to human diseases is now of considerable interest. The authors present a patient in whom CD4-CD8-TCR-alpha beta+ T-cells showed monoclonal proliferation in the peripheral blood for more than 3 years, then disappeared spontaneously, followed by subsequent development of Hodgkin's disease. The pathologic roles of double-negative T-cell proliferation in this case are discussed from the viewpoint of premalignancy in lymphoproliferative diseases.

Angiolymphoid Hyperplasia with Eosinophilia↗
PubMed1994

Analysis of NF1 gene mutations in neurofibromatosis type 1 patients in Japan.

Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders and is characterized by abnormalities in multiple tissues derived from the neural crest. Here, we report two novel deletion mutations of the NF1 gene from two out of 25 unrelated Japanese NF1 patients. These mutations were detected using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis. Sequencing analysis revealed a 4 base pair (bp) deletion at 5679 (5679delACTG) in exon 30 in one patient and a single bp deletion at 5949 (5949delA) in exon 32 in the other patient. Both of these mutations resulted in frameshifts, followed by premature terminations of the mutant allele. Because only a few large rearrangements of the NF1 gene have been reported in NF1 patients, it is likely that subtle mutations such as these are common.

Amino Acid Sequence↗
PubMed1994

Up-regulation of tissue factor mRNA in human umbilical vein endothelial cells by calmodulin inhibitor W7.

Tissue factor (TF) is an integral membrane glycoprotein that serves as a cofactor for the blood coagulation factor VIIa. The induction of TF synthesis and activity on the surface of endothelial cell membrane is initiated by lipopolysaccharide (LPS), phorbol 12-myristate 13-O-acetate (PMA), and inflammatory factors such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF alpha). Treatment of cells with 1 micrograms/ml LPS induced an 8.7-fold increase in total TF activity compared with nontreated cells. Co-incubation with 1 micrograms/ml LPS and 30 microM W7, a potent calmodulin inhibitor, resulted an additional 2.0 fold increase in total TF activity. A similar tendency was observed after treatment with either TNF alpha plus W7, or IL-1 beta plus W7. The effect of W7 appeared to be synergistic since incubation with 30 microM W7 alone increased TF activity levels to only 1.5-fold that of control cells. Northern blot analysis showed that W7 and LPS-treated endothelial cells expressed about three times higher levels of TF mRNA compared to LPS-treated cells. Treatment with W7 and LPS resulted in a slow but large calcium influx into endothelial cells. This result suggest that the contribution of W7 may be dependent mainly on calcium influx by unknown mechanisms rather than direct inhibition of calmodulin, because calcium ionophore treatment also showed a synergistic effect on TF mRNA and activity expression.

Calcimycin↗
PubMed1994

Putative functions of phenylalanine-350 of Pseudomonas putida cytochrome P-450cam.

Cytochrome P-450cam hydroxylates d-camphor, using molecular oxygen and reducing equivalents transferred via putidaredoxin. We constructed mutant genes in which Phe-350 of P-450cam was replaced by Leu, Tyr, or His by site-directed mutagenesis, expressed them in Escherichia coli, purified the mutant proteins, and compared their enzymic properties with those of the wild type P-450cam. NADH oxidation rate of the Tyr mutant in the reconstituted system with putidaredoxin and putidaredoxin reductase was similar to that of the wild type enzyme, while the Leu mutant and the His mutant showed 67% and 17% activity of that of the wild type, respectively. The affinities of these mutant proteins for camphor and the oxidized form of putidaredoxin were much the same as those of the wild type protein. Rate constants for the reduction reaction of P-450cam by reduced putidaredoxin, a physiological electron donor for P-450cam, of Tyr and His mutants were much the same as that of the wild type enzyme, whereas the Leu mutant showed approx. half that of the wild type. Thus, the aromatic ring of Phe-350 of P-450cam probably contributes to enhancing efficiency of the electron transfer yet does not seem to be essential for the reaction.

Base Sequence↗
PubMed1994

Expression of insulin-like growth factor II by a gastric carcinoma associated with hypoglycaemia.

A gastric cancer with liver metastases was associated with low morning levels of plasma glucose (24 mg/dl), insulin (< 2.5 microU/ml) and growth hormone (0.23 ng/ml). Primary and metastatic tumour tissue stained positively with anti-insulin-like growth factor II (IGF-II) monoclonal antibody. Western immunoblot analysis revealed a high molecular weight IGF-II in the serum: 15 kDa (normal: 7.5 kDa). Postmortem reverse transcription polymerase chain reaction on mRNA from both sites revealed 471 base pairs size cDNA encoding prepro-IGF-II. These results suggest that the gastric carcinoma encoded, expressed, and secreted IGF-II, probably causing the extrapancreatic tumour hypoglycaemia.

Aged↗
PubMed1994

Nonsense mutations at Arg-1947 in two cases of familial neurofibromatosis type 1 in Japanese.

We report two familial cases of NF1 presenting as C to T transitions changing an Arg-1947 codon to a stop codon. In one of the two families, cosegregation of the mutation with NF1 was demonstrated, indicating this mutation causes the disease in this family. As the same mutation at Arg-1947 has been reported previously in three cases of unrelated Caucasians (two are sporadic; the origin of the other is not reported), the codon at Arg-1947 (CGA) in the NF1 gene is considered to be a hotspot common among different ethnic groups and also among familial and sporadic cases.

Adult↗
PubMed1994

Penetration by bull spermatozoa into the zona pellucida of dead bovine oocytes recovered from frozen-thawed ovaries.

The present study was carried out to determine if the zona pellucida of dead bovine oocytes obtained from ovaries stored at -196 degrees C could be used to assess penetrability of capacitated bull spermatozoa. Follicular oocytes were recovered from bovine ovaries which were frozen slowly in a box containing dry ice, plunged into liquid nitrogen, and thawed at 37 degrees C. The dead oocytes were inseminated with various concentrations of spermatozoa preincubated for 0 to 4 h. Sperm penetration rates of the dead oocytes were significantly altered by sperm concentration and preincubation time. Dead and living oocytes matured in vitro (control) gave similar patterns of penetrability based on sperm preincubation time. When sperm concentration was increased, the rate of multiple sperm penetration into the dead oocytes also increased significantly, but the rate of penetration into living oocytes did not alter significantly. All dead oocytes from ovaries stored at -196 degrees C for 1 d to 3 mo were penetrated at similar rates by spermatozoa preincubated for 1-h. Thus, we conclude that dead follicular oocytes recovered from frozen ovaries are useful for the assessment of sperm capacitation and/or the acrosome reaction in cattle.

Journal Article↗
PubMed1994

Effects of cycloheximide on chromatin condensations and germinal vesicle breakdown (GVBD) of cumulus-enclosed and denuded oocytes in cattle.

To determine if newly synthesized protein is imperative for the resumption of meiosis in bovine follicular oocytes collected from small antral follicles, cumulus-enclosed and denuded oocytes were cultured in TCM-199 both with and without various concentrations of the protein synthesis inhibitor, cycloheximide. After 11 h of culture in inhibitor-free medium, all oocytes had undergone germinal vesicle breakdown (GVBD). However, when concentrations of more than 1.0 mug/ml cycloheximide were added to the medium, the meiotic resumption of bovine oocytes was completely blocked. This inhibitory effect of cycloheximide was fully reversible after removal of the inhibitor from maturation media. Germinal vesicle breakdown following removal of cycloheximide occurred twice as fast as in the control medium. Nevertheless, when oocytes were arrested at the germinal vesicle (GV) stage by cycloheximide, a significantly higher proportion of chromatin condensation (40 to 57%) was observed in denuded oocytes than in cumulus-enclosed oocytes (11 to 22%). Thus the cycloheximide treatment could not prevent the chromatin condensation in only denuded oocytes. We conclude that protein synthesis is a prerequisite for GVBD in bovine follicular oocytes and that cumulus cells are responsible for the complementary regulation of the chromatin condensation at the GV stage, regardless of protein synthesis in the oocytes.

Journal Article↗
PubMed1994

Nucleotide sequence of the gene encoding a repressor for the cytochrome P-450cam hydroxylase operon on the Pseudomonas putida CAM plasmid.

The camR gene of Pseudomonas putida encodes a repressor which regulates expression of the cytochrome P-450cam hydroxylase operon (camDCAB). We determined the nucleotide sequence of 1134 continuous base pairs, including the camR gene. When comparing the amino acid sequence deduced from the open reading frame of the gene sequence with that of amino-terminal five residues of the cam repressor, purified from Pseudomonas putida, we found that the camR gene encodes a protein of 186 amino acids, with a molecular mass of 20.4 kDa. The start codon for the cam repressor is the rare initiation codon GTG. The cam repressor predicted from the camR sequence contained a region similar to that seen in other DNA-binding proteins.

Amino Acid Sequence↗