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Biomedical subjects

H Ohi

Publications and source records attributed to H Ohi.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of in vitro ovarian cancer cell invasion by modulation of urokinase-type plasminogen activator and cathepsin B.

HOC-I ovarian cancer cells express the single-chain form of the urokinase-type plasminogen activator (uPA) and cathepsin B (cath B) on their cell surface. The significance of the expression of cell surface uPA/cath B activity to the invasive potential was examined by preincubating with uPA/cath B-modulating agents in in vitro invasion assay. The anti-uPA monoclonal antibody 394 effectively inhibited invasion in a dose-dependent manner. On the contrary, anti-cath B antibody did not affect the invasive potential of the cells. E-64, a specific inhibitor for cysteine proteases, blocked invasion as effectively as monoclonal antibody 394. The data reveal that the uPA and cysteine proteases contribute significantly to the invasive capacity of the cells. We suggest that the cysteine proteases facilitate the action of uPA, possibly by activating proenzyme uPA produced by cancer cells. Evidence for the role of a cathepsin-uPA activation cascade in HOC-I cell invasion is provided.

Cathepsin B↗
PubMed1992

A new form of cytochrome P-450 responsible for mutagenic activation of 2-amino-3-methylimidazo[4,5-f]quinoline in human livers.

Antibodies to P-450IA2 strongly inhibited the mutagenic activation of 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole acetate but not aflatoxin B1 in human liver microsomes. The anti-rat P-450IA2 antibodies were capable of recognizing two proteins which show different mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of human liver microsomes. A new form of cytochrome P-450 (designated P-450-HM4) cross-reactive with anti-rat P-450IA2 antibodies showing that the smaller molecular weight was purified from human liver microsomes by means of the fast-performance liquid chromatography system. The molecular weight of P-450-HM4 was estimated to be 49,000, which was apparently different from that of P-450PA (human P-450IA2). The antibodies to P-450-HM4 did not cross-react with P-450PA (human P-450IA2) but inhibited to various extents the mutagenic activation of IQ in microsomes from human livers. In addition, P-450-HM4 showed significant mutagen-producing activity from IQ in a reconstituted system. Together with these and other results reported previously, it is concluded that at least two forms of cytochrome P-450 [P-450-HM4 and P-450PA (human P-450IA2)] are involved in the mutagenic activation of IQ in human liver.

Antibodies↗
PubMed1992

Toxicological significance of dog liver cytochrome P-450: examination with the enzyme expressed in Saccharomyces cerevisiae using recombinant expression plasmid.

A complementary DNA (cDNA) coding for a form of beagle dog cytochrome P-450 (Dah1), which is the orthologue to the CYP1A1 cDNA of rat, mouse and human, was inserted between the alcohol dehydrogenase (ADH) promoter and terminator regions of the yeast expression vector pAAH5. On introduction of the resulting recombinant plasmid pDC-1, Saccharomyces cerevisiae strain AH22 cells synthesized up to 1.5 x 10(5) molecules per cell of cytochrome P-450 protein (P-450(Dah1)). The carbon monoxide-bound reduced form of P-450(Dah1) showed an absorption peak at 447 nm and specific content of P-450(Dah1) was about 0.1 nmole P-450 per mg of microsomal protein. P-450(Dah1) cross-reacted with antibodies to rat P-448-H (CYP1A2) and dog P-450-D2 (CYP1A2). P-450(Dah1) activated 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) most efficiently in the umu test and exhibited a high activity of aryl hydrocarbon hydroxylase toward benzo[a]pyrene.

Animals↗
PubMed1992

Accelerated decay of the cell bound C4b2a complex by serum of patients with membranoproliferative glomerulonephritis and acute poststreptococcal glomerulonephritis.

Serum from patients with membranoproliferative glomerulonephritis (MPGN) and acute poststreptococcal glomerulonephritis (APSGN) accelerated the decay of the cell bound C4b2a (C42) and C4b hemolytic activity relative to pooled normal human serum (pNHS) after 5 min incubation at 30 degrees C in EDTA-GVB. The accelerated decay of the C42 hemolytic activity was heat stable (56 degrees C 30 min) and was inhibited by monoclonal antibody against human C4 binding protein (MoAb:C4BP) or C4 binding protein (C4BP) depleted serum. C4 nephritic factor (C4NeF) was employed to stabilize the labile classical pathway C3 convertase C42 complex. Serum from patients with MPGN and APSGN reduced the C4NeF stabilizing activity. Sera from 32 of 46 patients with MPGN and all of 7 patients with APSGN reduced the C42 hemolytic activity relative to 50 normal human serum (NHS) after 5 min incubation at 30 degrees C in EDTA-GVB, and there was no relationship with the serum concentration of C4BP. In vivo, accelerated decay of C42 convertase might interfere with the clearing and processing mechanism of circulating immune complexes (IC) by reducing deposition of C3b on the IC lattice.

Acute Disease↗
PubMed1992

Characterization and clinical evaluation of tumor-associated antigen CA54/61 identified by monoclonal antibodies MA54 and MA61 in epithelial ovarian cancer.

Monoclonal antibodies (moABs) MA54 and MA61, directed toward the O-linked mucin-type glycoprotein, have been established and showed highly specific reactivity with human ovarian cancer. Fetal intestinal and colonic mucosal cells expressed this antigen and meconium staining was also frequently positive. To investigate the characteristic of an epitopic carbohydrate recognized by these moABs, the reactivity of each moAB with meconium extract was monitored by solid-phase enzyme-linked immunosorbent assay with mono-, di-, and oligosaccharides. MA54 and MA61 react with meconium extract and the reactivities of these moABs are neuraminidase sensitive. Ovine submaxillary mucin had a strong inhibitory activity toward the reaction between meconium extract and MA54 as well as MA61, suggesting that these moABs recognize NeuAc 2-6GalNAc epitope in meconium. The second aim of this study is to investigate the possible application of moABs to diagnose ovarian cancer and to compare these levels with those of the CA125 antigen. While serum CA54/61 antigen levels were elevated in 44.4% of ovarian cancer cases and serum CA125 antigen levels were elevated in 86.7% of the same population, the use of both assays indicated a sensitivity of detection of 97.8% (44 of 45 patients) in the population studied.

Antibodies, Monoclonal↗
PubMed1992

Significance of C3 nephritic factor (C3NeF) in non-hypocomplementaemic serum with membranoproliferative glomerulonephritis (MPGN).

C3NeF is an autoantibody of C3 convertase (C3bBb) and is often detected in the serum of hypocomplementaemic MPGN patients. Serum samples from 104 non-hypocomplementaemic MPGN patients (C3NeF) were studied. C3NeF, which cannot activate the alternative pathway, was found in the sera of 6 patients. We examined the C3NeF in purified IgG from five of the non-hypocomplementaemic serum samples (non-hypo C3NeF) and four hypocomplementaemic serum samples (hypocomplementaemic C3NeF) to determine why C3NeF does not induce C3 splitting and hypocomplementaemia. Purified IgG from non-hypo C3NeF stabilized EAC4b3bBb cells in a manner similar to IgG from hypocomplementaemic C3NeF in EDTA gelatin veronal buffer. However, the non-hypo C3NeF IgG did not stabilize C3 convertase (EAC4b3bBb cells) in the presence of control proteins (factors H and I), whereas the hypocomplementaemic C3NeF IgG did. The C3NeF in the hypocomplementaemic serum displayed two characteristics: (i) inhibition of intrinsic decay of Ce convertase (C3bBb); and (ii) inhibition of extrinsic decay by factors H and I. Although the C3NeF in the non-hypocomplementaemic sera did inhibit the intrinsic decay in a manner similar to the hypocomplementaemic C3NeF IgG, it did not inhibit the extrinsic decay. Due to the different characteristics of hypocomplementaemic C3NeF and non-hypo C3NeF in the serum samples, the non-hypo C3NeF did not activate C3. Therefore, we conclude that C3NeF exhibits a heterogeneity which is very important in relation to the pathogenesis of MPGN.

Complement C3 Nephritic Factor↗
PubMed1992

Effects of oxygen concentration on the metabolism of anisole homologues by rat liver microsomes.

1. The effects of oxygen concentration were studied on the metabolic pathways of anisole homologues (anisole, phenetole and isopropoxybenzene) catalysed by liver microsomes from phenobarbital-treated rats. 2. With increase of oxygen concentration, the rate of anisole o-hydroxylation reached a plateau at about 35 microM O2, while the rates of O-demethylation and aromatic p-hydroxylation were still increasing at 223 microM O2 (air). 3. The rates of all three metabolic reactions of phenetole reached plateau levels at about 80 microM O2. 4. The rates of all three metabolic reactions of iso-propoxybenzene were still increasing as 223 microM O2 (air). 5. The ratio of aromatic p-hydroxylation or O-dealkylation to aromatic o-hydroxylation decreased in anisole metabolism, and showed no uniform change in phenetole and isopropoxybenzene metabolism with decreasing oxygen concentration. 6. The ratio of aromatic p-hydroxylation to O-dealkylation was essentially constant over the range of oxygen concentration studied in anisole and phenetole metabolism, while in iso-propoxybenzene metabolism the ratio was different between higher and lower oxygen concentrations than 60 microM. 7. This series of compounds with increasing chain length did not show homologous changes in rates of product formation or O2 dependent of product formation.

Animals↗
PubMed1992

[A new method for diagnosis of amniotic fluid embolism by means of monoclonal antibody TKH-2 that recognizes mucin-type glycoprotein, a component in meconium].

Five monoclonal antibodies (moABs TKH-2, MA54, MA61, B72.3, and CC49), directed toward the O-linked mucin-type glycoprotein, showed signs of specific reactivity with human meconium. The reactivity of these moABs with meconium extract was examined by solid-phase ELISA with different native and sialidase-treated glycoproteins. All moABs react with meconium extract, whereas the reactivities of TKH-2, MA54, and MA61 are sialidase sensitive and the reactivity of TKH-2 with meconium extract was only inhibited by ovine submaxillary mucin (OSM), indicating that TKH-2 is the most sensitive and specific antibody clearly directed to the sialyl Tn antigen in meconium. The possible application of TKH-2 to diagnose amniotic fluid embolism (AFE) has been prelimiarily investigated. We demonstrated that the concentration of sialyl Tn antigen in the serum of patients with AFE was significantly increased, indicating that meconium was released into the maternal circulation. Our method for detecting sialyl Tn antigen in the serum of AFE patients is a direct way to demonstrate the release of meconium into the maternal circulation, and is a simple, rapid, non-invasive and sensitive method for the diagnosis of AFE.

Amniotic Fluid↗
PubMed1992

[Suprasellar arachnoid cyst associated with precocious puberty: report of an operated case and review of the literature].

The pathogenesis remains unknown in the majority of patients with precocious puberty, and yet infrequently such causative cerebral lesions as hypothalamic hamartomas are associated with sexual precocity. We reported a rare case of suprasellar arachnoid cyst in an infant presenting with precocious puberty, which eventually disappeared after a cyst-peritoneal shunt. It was believed that the mass effect of the arachnoid cyst upon the hypothalamus was, at least in part, responsible for development of precocious puberty. The role of surgical decompression of the cyst was also discussed. A one-year-old girl was admitted to the hospital for evaluation of genital bleeding which had persisted on and off for two months. The height, 80cm, and the weight, 12.4kg, exceeded by far the two standard deviations from the mean level of the normal population. In addition she had the development of breast tissue as classified Tanner's Stage II, and both pubic and axillary hair. The bone age by skeletal survey of the hand was rated as 3 years. Endocrinological examination showed that serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and estradiol had increased for her age, to levels equivalent to those for females at puberty. An LH-RH test revealed an excessive LH reaction. There were no definite neurological deficits. CT and MRI demonstrated the presence of a large arachnoid cyst involving the suprasellar region as well as the right middle and posterior fossa. After the patient underwent a cyst-peritoneal shunt, the cyst decreased in size and such symptoms as genital bleeding and breast growth disappeared. Serum levels of her LH and FSH also significantly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachnoid Cysts↗
PubMed1992

Six-base deletion occurring in messages of human cytochrome P-450 in the CYP2C subfamily results in reduction of tolbutamide hydroxylase activity.

We isolated and expressed a clone, hPA6, possibly corresponding to the CYP2C9 cDNA. Compared with the other CYP2C9 cDNA clones, hPA6 showed a 6-nucleotide deletion near its middle. From the same cDNA library, we could also isolate another cDNA clone, named hPA22, which retained the 6 bases. For clarification of the effect of the 2-amino acid deletion resulting from the 6-base deletion on enzymatic activities, both clones were expressed in yeast. The expressed enzymes showed tolbutamide hydroxylase activities, and these activities were inhibited by antibodies against P-450-HM2, a probable CYP2C9. The activity of the enzyme encoded by hPA6 was lower than that encoded by hPA22; thus the 2-amino acid deletion in the CYP2C9 reduced the enzymatic activity.

Amino Acid Sequence↗
PubMed1992

Use of synthetic H disaccharides as acceptors for detecting activities of UDP-GalNAc:Fuc alpha 1-->2Gal beta-R alpha 1-->3-N-acetylgalactosaminyltransferase in plasma samples from blood group A subgroups.

Concentrations of blood group A-specified alpha(1-->3)-N-acetylgalactosaminyltransferase (A enzyme) were measured in human plasma of blood groups A1, A2, and A3 by using chemically synthesized H disaccharides and H type 1 and type 2 trisaccharides attached to hydrophobic aglycones as acceptors. When the trisaccharides were used as acceptors, enzyme activities were reduced in samples from A2 and A3. However, the H disaccharides were shown to be good acceptors even for enzymes from A2 and A3, and no significant difference in enzyme concentration was detected in any of the plasma tested.

ABO Blood-Group System↗
PubMed1991

Secretory expression of the human serum albumin gene in the yeast, Saccharomyces cerevisiae.

We have fused a cDNA gene encoding mature human serum albumin (HSA) to several secretory leader-encoding sequences. The hybrid genes were cloned into an episomal vector under the control of several yeast promoters and then introduced into yeast cells. The GAL1 promoter in combination with either the native HSA pre-sequence or a modified HSA pre-sequence gave the highest production of immunoreactive HSA, 90 mg/liter being reached in a shake flask culture. The invertase pre-sequence, the mating factor alpha 1 prepro-sequence, and the modified HSA pre-sequence directed accurate processing. In contrast, the chicken lysozyme pre-sequence and the native HSA pre-sequence directed incorrect processing. Episomal vectors were unstable within the host cells under non-selective culture conditions. To improve the plasmid stability, the hybrid genes were incorporated into an integrative vector. Transformants carrying multicopies of the plasmid integrated at the LEU2 locus stably secreted HSA. The highest yield of 65 mg/liter in a shake flask culture was obtained with the combination of the yeast glyceraldehyde-3-phosphate dehydrogenase promoter and the modified HSA pre-sequence. By constructing transformed strains containing multicopies of plasmids integrated at both the chromosome LEU2 and HIS4 loci, we have obtained a stable strain that continuously secretes as much as 85 mg HSA per liter of culture medium.

Amino Acid Sequence↗
PubMed1991

Prevention by urinastatin of cis-diamminedichloroplatinum-induced nephrotoxicity in rabbits: comparison of urinary enzyme excretions and morphological alterations by electron microscopy.

Acute nephrotoxicity was produced by 3 mg/kg intramuscular administrations of cis-diamminedichloroplatinum (CDDP) in rabbits. Urinary enzyme excretions of arylamidase and gamma-glutamyl transpeptidase, and morphological alterations by electron microscopy were used as endpoints to quantitate the severity of nephrotoxicity. The preventive effect of urinastatin (US), a trypsin inhibitor, on CDDP-induced nephrotoxicity was evaluated. The alteration of urinary enzyme excretions did not parallel the severity of renal morphological changes. In proximal tubular cells, the morphological alterations consisting of nuclear irregularity, brush border disruption, and lysosomal membrane destruction were observed. In contrast, in rabbits treated concurrently with CDDP and 10,000 unit/kg of US, CDDP-induced morphological changes observed in rabbits without US were completely absent. The differences in urinary enzyme excretions and morphological alterations between US-treated rabbits and the US-nontreated group were enough to fully account for the drastic protective effect of US against CDDP nephrotoxicity.

Animals↗
PubMed1991

Formation of an antibacterial metabolite from a new macrolide compound 23-O-benzyl-5-mycaminosyl-tylonolide (TMC-101), by a hepatic microsomal drug-metabolizing enzyme system.

Upon incubation of 23-O-benzyl-5-mycaminosyl-tylonolide (TMC-101) with liver microsomes in the presence of an nicotinamide adenine dinucleotide phosphate-generating system, at least four metabolites were formed: two of them were also formed by an enzyme(s) in rat serum. One of the metabolites formed by liver microsomes possessed antibacterial activity comparable to TMC-101 as examined by bioautography using Micrococcus luteus ATCC 9341 as a tester strain. Incubation of TMC-101 with rat serum degraded most of the parent compound and did not form the active metabolite. The capacity of liver microsomes to produce the active metabolite was increased by pretreatment of rats with 3-methylcholanthrene, phenobarbital and polychlorinated biphenyl. The metabolite with the antibacterial activity was estimated not to be formed by the N-demethylation of TMC-101, and was chemically unstable.

Animals↗
PubMed1991

[Multiple aspergillus brain abscess complicated with systemic lupus erythematosus--case report].

A 15-year-old female was hospitalized for the treatment of systemic lupus erythematosus complicated with nephritis. She improved with administration of steroid hormones and an immunosuppressant, plasma exchange, and dialysis. However, a lung abscess developed 6 months after admission, and multiple brain abscesses appeared 2 months after the onset of the lung abscess. The lung abscess faded with oral administration of fluocytosine and intravenous administration of miconazole, but the brain abscesses enlarged. Intrathecal administration of miconazole was not effective. Therefore, the abscess in the right frontal lobe was surgically removed and an Ommaya's reservoir was placed in the anterior horn of the right lateral ventricle. Aspergillus was identified in the removed abscess. Subsequently, miconazole was administered intraventricularly through the Ommaya's reservoir 10 mg daily for 1 month. The abscesses in the left parietal lobe gradually diminished. One year later, she complained of right hypesthesia again. Computed tomography scan revealed enlargement of the abscess. Miconazole was administered intravenously and intraventricularly for 1 month. Second craniotomy was performed 16 months after the first surgery and the abscess was completely removed. She was discharged with mild hypesthesia of the right leg. It is concluded that intraventricular administration of miconazole through an Ommaya's reservoir is an effective therapy for central nervous system aspergillosis.

Adolescent↗
PubMed1991

[Chronic subdural hematoma associated with primary thrombocythemia; report of an operated case, using plateletpheresis].

Primary thrombocythemia is a chronic proliferative disorder of the bone marrow in which either thrombotic or paradoxically hemorrhagic symptoms or both may occur due to the pathological increase in the number of platelets. The mechanism of hemorrhagic diathesis in this disorder is not fully defined. We presented a rare case of primary thrombocythemia developing chronic subdural hematoma which was surgically managed with the use of plateletpheresis. It was believed that plateletpheresis was useful in controlling hemorrhagic complications during surgery associated with primary thrombocythemia. A 62-year-old man was admitted to the hospital for evaluation of motor weakness on the right side. The patient had no episode of head trauma. CT scan demonstrated the presence of subdural hematoma in the left frontotemporal region with significant ventricular shift and deformity. No definite abnormalities were disclosed on laboratory examination except for the hemogram in which platelet count was extremely elevated and read 109 x 10(4)/mm3. Examination of bone marrow smears disclosed an abnormal increase in megakaryocytes. Despite the increase in the number of the platelets, other coagulation studies gave normal results. Prior to surgery plateletpheresis was attempted in hopes of reducing the number of peripheral platelets and eventually avoiding the risk of hemorrhagic complications during surgery. As a result surgery for aspiration of the hematoma was successfully performed. The postoperative course remained uneventful as the patient continuously underwent two courses of plateletpheresis and chemotherapy. The patient was discharged with no neurological deficits and the peripheral platelets remained reduced in number at 50 x 10(4)/mm3 two months after discharge.

Chronic Disease↗