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Biomedical subjects

M Ohno

Publications and source records attributed to M Ohno.

At least 397 records · Page 22Linked to original sources
PubMed1991

[A case of diphenylhydantoin-induced pneumonitis].

A 60-year-old man had been administered diphenylhydantoin (DPH) for prevention of convulsive seizures following clipping of an aneurysm of the middle cerebral artery. About one month after the commencement of DPH administration, he developed cough and low grade fever. He was treated with various antibiotics, but his condition increasingly worsened. Chest X-ray film revealed bilateral interstitial processes throughout the entire lung fields. Transbronchial lung biopsy was performed and the obtained specimen showed histological findings compatible with drug-induced pneumonitis. Administration of DPH was stopped immediately and 50 mg/day of prednisolone was started. The patient's condition rapidly improved, and the abnormal shadows on chest X-ray film gradually diminished. The lymphocyte stimulation test by DPH was positive with a stimulation index of 282%.

Humans↗
PubMed1991

[A study on BrdU labelling index of gastric cancer using in vitro labelling method].

In order to reveal the effect of environmental factors to BromodeoxyUridine labelling index (BrdU L.I.) and its usefulness as clinicopathological information, 522 specimens obtained from 121 lesions of gastric cancer were studied. Five hundred twenty two specimens in which BrdU had been incorporated using an in vitro labelling method were divided into 3 groups according to their degree of necrosis and cell infiltration. The average L.I. of the specimens with no or slight necrosis was 23.3 +/- 8.7%, medium, 14.2 +/- 10.0%, and severe necrosis, 6.6 +/- 3.8%, with no or slight cell infiltration, 25.3 +/- 9.5%, medium, 21.0 +/- 7.1%, and severe cell infiltration, 21.2 +/- 6.1%, therefore L.I. correlated to necrosis and cell infiltration. Representative values for each lesion were adopted and compared using 3 methods. In method A, a representative value of the L.I. for each lesion was chosen using all biopsy specimens, method B using specimens without necrosis, and method C, specimens without necrosis and cell infiltration. L.I. correlated to stage and the lymphnode metastasis only using methods, B and C and more strictly using method C. Necrosis and cell infiltration should be considered in adopting a representative value of the L.I. for each lesion. Method C is considered to be a best among the three studied, and the L.I. of gastric cancer may be considered a clinicopathological marker.

Biopsy↗
PubMed1991

A cytogenetic study of spontaneous abortions with direct analysis of chorionic villi.

The karyotypes of 144 spontaneous abortuses were determined using direct chromosome preparations from chorionic villi. The frequency of chromosome abnormality was 69.4%, which is considerably higher than figures cited in most previous cytogenetic surveys using the conventional method of cell culturing. Autosomal trisomy was the predominant abnormality (64%), followed by polyploidy (9%), monosomy X (7%), structural rearrangements (6%), mosaicism (6%), double trisomy (4%), and double chromosome anomaly (3%). Direct preparations have advantages in that results can be obtained rapidly, the success rate of karyotyping is satisfactory, and maternal-cell contamination is minimal.

Abortion, Spontaneous↗
PubMed1991

[Clinical significance of specific IgG4 antibody in serum].

Specific IgG4 antibodies in sera were measured by ELISA in allergic patients who were diagnosed as susceptible to one or more allergens among mite, milk, soybean or egg white, and also in a non-allergic control group, and their diagnostic significance was investigated. The results obtained were as follows. 1. The level of specific IgG4 antibody was significantly higher in each allergic group than in the non-allergic group. 2. The positive rates in the specific IgG4 antibody determination were higher than those in RAST in the milk-, soybean- and egg white-allergic groups. 3. In each allergic group, the causative allergens were detected more accurately by measuring both specific IgG4 antibody and IgE antibody (RAST) than IgE alone. 4. The positive rates in the specific IgG4 antibody determination were higher than those in the skin test in each allergic group. 5. It was demonstrated that the combination of the skin test with specific IgG4 antibody measurement ensured a more accurate detection of causative allergens than the skin test alone. These results indicated that the measurement of the specific IgG4 antibody is a helpful method to detect the causative allergens in allergic patients.

Adolescent↗
PubMed1990

Stretch may enhance the release of endothelium-derived relaxing factor in rabbit aorta.

The effect of vascular stretch on the release of EDRF was studied by measuring tissue cGMP levels of rabbit. Aortic rings of rabbit were quick-frozen in liquid nitrogen during varying resting tensions, and cGMP contents were determined by radio-immunoassay. The tissue cGMP levels significantly elevated with the increase in resting tension in endothelium-intact rings, but not in endothelium-denuded rings. Deprivation of extracellular calcium abolished the stretch-induced elevation of tissue cGMP levels in endothelium-intact segments. These stretch-induced endothelium dependent tissue cGMP elevations were unaffected by Ca2+ channel blockers, nicardipine and diltiazem. Data suggest that vascular stretch may release EDRF via mechanism dependent on extracellular calcium, but probably not through voltage-dependent calcium channel.

Animals↗
PubMed1990

A nuclear cap binding protein from HeLa cells.

We have identified a cap binding protein in a HeLa nuclear extract using a gel mobility shift assay probed with capped RNA. Subcellular fractionation of HeLa cells revealed that the majority (about 70%) of the cap binding activity is present in the nuclear extract, about 20% is in the cytoplasmic S100 fraction, and almost none in the ribosome-high salt wash fraction, indicating that the protein in active form localizes mainly in the nuclei. Competition experiments with various cap analogues showed that the G(5')ppp(5')N-blocking structure as well as the methyl residue at the N7 position of the blocking guanosine is important for the binding of this protein, and that the trimethylguanosine cap structure which exists at the 5' termini of many snRNAs is not recognized by this protein. Immunoprecipitation experiments using various anti-snRNP antibodies suggested that this protein is partially associated with U2 snRNP. We purified this protein to near homogeneity from a HeLa nuclear extract by several chromatographic procedures including capped RNA-Sepharose chromatography. The purified protein shows molecular weight of 80 kilodaltons, as judged by SDS gel electrophoresis, and binds specifically to the cap structure.

Binding, Competitive↗
PubMed1990

Detection of antibodies to human T-lymphotropic virus type I by using synthetic peptides.

We describe an enzyme-linked immunosorbent assay (ELISA) for antibodies to HTLV-I using synthetic peptides corresponding to antigenic regions of HTLV-I structural protein. We observed that the peptides amino acid 100-119, 100-130, 131-160 and 295-314 of the gag protein, and 89-115, 175-199, 350-386 and 458-488 on the env protein correspond to the antigenic regions of HTLV-I structural protein. In particular, the peptide corresponding to amino acid 100-130 of the gag protein reacted with antibodies in all sera from HTLV-I carriers diagnosed by particle agglutination assay (PA) and indirect immunofluorescence assay (IF), but did not react with sera from healthy volunteers judged to be negative by PA and IF. Our results indicate that the ELISA using the peptide 100-130 of the gag protein can be used for donor screening of HTLV-I antibodies.

Amino Acid Sequence↗
PubMed1990

Specific inhibitory conformation of dipeptides for chymotrypsin.

Based on the analyzed conformation of a chymotrypsin inhibitor H-delta Phe-Phe-OMe, we have designed a series of diastereomeric phenylalanylphenylalanine methyl esters and derivatives as possible inhibitors. Among the peptides synthesized, H-D-Phe-L-Phe-OMe was found to be very resistant to chymotrypsin in spite of its L-Phe-OMe structure at the C-terminus. It inhibited the enzyme fairly strongly and competitively with Ki = 9.0 x 10(-5) M in the assay using Ac-Tyr-OEt as a substrate. The measurements of the NOEs in high-resolution 1H-NMR analyses indicated the presence of the hydrophobic core built by the intramolecular interaction between the D-Phe-phenyl and ester-methyl groups. It was suggested that this core interacts with the chymotrypsin S2 site (Trp215) and Phe2 with the S1 site. The backbone structure of this dipeptide was assumed to be in an inhibitory conformation that fits the active center of the enzyme.

Amino Acid Sequence↗
PubMed1990

MR imaging of wallerian degeneration in the human brain stem after ictus.

Magnetic resonance (MR) imaging of wallerian degeneration in the brain stem was studied in 30 hemiplegic patients within 12 months of ictus. As early as 25 days after the ictus, decreased signal intensities on proton-density(PD)-weighted images were observed in the brain stem ipsilaterally. This hypointensity gradually approached an isointense stage during 70-80 days after the ictus, abnormal intensities were not detected in any pulse sequence. We termed this phenomenon "Fogging effect of wallerian degeneration". In later stages, at least 81 days after the ictus, increased signal intensities on T2-weighted images, with or without decreased signal intensities on T1-weighted images, were observed in the brain stem, ipsilaterally. Finally, at least six months after the ictus, mild shrinkage of the ipsilateral brain stem was newly detected on the T1-weighted images. MR imaging has proven to be a sensitive diagnostic modality for evaluating wallerian degeneration in the brain stem.

Brain Stem↗
PubMed1990

Minaprine improves impairment of working memory induced by scopolamine and cerebral ischemia in rats.

Using a repeated acquisition procedure in a three-panel runway apparatus, the effects of minaprine on the impairment of working memory produced by scopolamine, ethylcholine aziridinium ion (AF64A) or cerebral ischemia were investigated in rats. Minaprine (3.2-32 mg/kg IP) as well as idebenone (10-100 mg/kg IP) and physostigmine (0.1-0.32 mg/kg IP) dose-dependently reduced the increase of errors (pushes made on the two incorrect panels located at each choice point) induced by 0.56 mg/kg IP scopolamine. Cerebral ischemia for 5 min caused a significant increase of errors in the runway task. Minaprine at 3.2 and 10 mg/kg administered IP immediately after blood recirculation and again 30 min before the runway test conducted 24 h after ischemia, significantly reduced increases in errors expected to occur after 5 min of ischemia. Physostigmine 0.1 mg/kg similarly attenuated the increase in errors in ischemic rats. However, minaprine at doses up to 32 mg/kg IP failed to reduce the increase of errors induced by AF64A 2.5 nmol injected into the dorsal hippocampus. These findings suggest that minaprine exerts an ameliorating effect on amnesia produced by scopolamine and cerebral ischemia, probably through mediation of its stimulant action on central cholinergic systems.

Animals↗
PubMed1990

Purification and amino acid sequence of basic protein I, a lysine-49-phospholipase A2 with low activity, from the venom of Trimeresurus flavoviridis (Habu snake).

A basic protein (pI 10.2), named basic protein I, was purified to homogeneity from the venom of Trimeresurus flavoviridis (Habu snake) after four chromatographic steps. The amino acid sequence of this protein was determined by sequencing the S-pyridylethylated derivative of the protein and its peptides produced by chemical (cyanogen bromide and formic acid) and enzymatic (chymotrypsin, Achromobacter protease I, and Staphylococcus aureus V8 protease) cleavages. The protein consisted of 122 amino acid residues and was similar in sequence to phospholipases A2 from the venoms of crotalid and viperid snakes. A most striking feature of this protein is that aspartic acid at the 49th position common in phospholipases A2 is replaced by lysine. When the protein acted on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphorylcholine, oleic acid was preferentially released, indicating that the protein has phospholipase A2 activity. Its molar activity toward 1,2-dilauroyl-sn-glycero-3-phosphorylcholine, however, was 1.5% that of T. flavoviridis phospholipase A2 isolated previously. The fact that both affinity to Ca2+ and reactivity to p-bromophenacyl bromide of basic protein I are approximately one order of magnitude lower than those of T. flavoviridis phospholipase A2 might explain the low activity of basic protein I.

Amino Acid Sequence↗
PubMed1990

Preliminary crystallographic study of phospholipase A2 from the venom of Trimeresurus flavoviridis (habu snake).

Crystallization and a preliminary crystallographic study of Trimeresurus flavoviridis (habu snake) phospholipase A2 (PLA2) were carried out. Although crystals were obtained from various solutions, crystals suitable for X-ray analysis could be obtained from polyethylene glycol solutions only when a repeated seeding technique was applied starting from twinned crystals. The crystal is monoclinic with space group P21, with a = 44.1, b = 55.7, c = 48.8 A, and beta = 92.4 degrees. An asymmetric unit contains a dimer consisting of two identical subunits made of 122 amino acids. The crystal reflects X-rays beyond 2.5 A. A Pt derivative gave a good isomorphous crystal.

Animals↗
PubMed1990

Purification and amino acid sequence of basic protein II, a lysine-49-phospholipase A2 with low activity, from Trimeresurus flavoviridis venom.

A basic protein (pI 10.3), named basic protein II, was purified to homogeneity from the venom of Trimeresurus flavoviridis (Habu snake) after four chromatographic steps. The amino acid sequence of this protein was determined by sequencing the S-pyridylethylated derivative and its peptides produced by chemical (cyanogen bromide) and enzymatic (chymotrypsin, clostripain, and Staphylococcus aureus V8 protease) cleavages. The protein consisted of 122 amino acid residues and was found to be identical in sequence to basic protein I from the same source except that Asp-58 of basic protein I is replaced by asparagine. Like basic protein I, the structural feature of basic protein II is that Tyr-28 and Asp-49 common in phospholipases A2 from snake venoms and mammalian pancreas are replaced by asparagine and lysine, respectively. Thus, basic protein II belongs to the category of lysine-49-phospholipase A2. The action of basic protein II on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphorylcholine released only oleic acid, indicating that it has phospholipase A2 activity. Its molar activity toward 1,2-dilauroyl-sn-glycero-3-phosphorylcholine, however, was only 1.7% of that of T. flavoviridis phospholipase A2 isolated previously. Affinity for Ca2+ and reactivity toward p-bromophenacyl bromide of basic protein II were 8 and 5.3 times, respectively, smaller than those of phospholipase A2 from the same source, substantiating the low phospholipase A2 activity of basic protein II.

Amino Acid Sequence↗
PubMed1990

Cloning and sequence analysis of cDNA for Trimeresurus flavoviridis phospholipase A2, and consequent revision of the amino acid sequence.

A cDNA clone of Trimeresurus flavoviridis phospholipase A2 was isolated from the venom gland cDNA library using DNA amplified by polymerase chain reaction with oligonucleotide primers corresponding to the N- and C-terminal sequences of this enzyme. The amino acid sequence deduced from the cDNA nucleotide sequence determined by the dideoxy termination method was found to be inconsistent in the segment comprising the 69th to 81st positions from that reported previously [Tanaka, S. et al. (1986) J. Biochem. 99, 281-289]. Reinvestigation of the amino acid sequence of the peptide covering the sequence in question showed that the amino acid sequence predicted from the nucleotide sequence is correct. The sequence contains Asn-Asn-Gly (positions 69-71) and it was found that the Asn-Gly bond easily undergoes alpha-beta transpeptidation when digested with Achromobacter protease I at pH 9.0 but not seriously at pH 6.8. It is likely that the transpeptidation reaction caused a failure in the previous sequence determination. The cDNA clone obtained was 597 base pairs long and contained an open reading frame of 414 base pairs coding for 138 amino acid residues. A typical signal peptide sequence (16 amino acid residues long), located at the N-terminal moiety of the deduced sequence, was immediately followed by a polypeptide which corresponds to the mature enzyme. Northern blot analysis showed a single transcript only in the poly(A)+ RNA fraction of the venom gland but not in those of many other organs tested.

Amino Acid Sequence↗
PubMed1990

Purification and characterization of a coagulant enzyme, okinaxobin I, from the venom of Trimeresurus okinavensis (Himehabu snake) which releases fibrinopeptide B.

A coagulant enzyme, named okinaxobin I, has been purified to homogeneity from the venom of Trimeresurus okinavensis (Himehabu) by chromatographies on Sephadex G-100 and CM-Toyopearl 650M columns. The enzyme was a monomer with a molecular weight of 37,000 and its isoelectric point was 5.4. The enzyme acted on fibrinogen to form fibrin clots with a specific activity of 77 NIH units/mg. Fibrinopeptide B was released at a rate much faster than fibrinopeptide A. The enzyme exhibited 2 to 3 times higher activity toward tosyl-L-arginine methyl ester and benzoyl-L-arginine p-nitroanilide than bovine thrombin. The esterase activity was strongly inhibited by diisopropylfluorophosphate and phenylmethanesulfonyl fluoride, and to a lesser extent by tosyl-L-lysine chloromethyl ketone, indicating that the enzyme is a serine protease like thrombin. The N-terminal sequence was highly homologous to those of coagulant enzymes from T. flavoviridis and Bothrops atrox, moojeni venoms which preferentially release fibrinopeptide A. In order to remove most, if not all, of the bonded carbohydrates, the enzyme was treated with anhydrous hydrogen fluoride (HF), thereby reducing the molecular weight to 30,000. The protein contained approximately 260 amino acid residues when computation was based on this value. The HF-treated enzyme retained about 50% of the clotting and esterolytic (TAME) activities and preferentially released fibrinopeptide B from fibrinogen. The carbohydrate moiety is not crucial for enzyme activity but might be necessary for eliciting full activity.

Amino Acid Sequence↗