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Biomedical subjects

K Ohyama

Publications and source records attributed to K Ohyama.

At least 163 records · Page 9Linked to original sources
PubMed1990

Purification and characterization of anti-N lectin from Vicia unijuga leaves.

1. An anti-N lectin was extracted from Vicia unijuga leaves with phosphate-buffered saline (PBS). Purification of the lectin was achieved, after pretreatment of the PBS extract by ammonium sulfate fractionation and absorption with human M erythrocytes, by using a combination of conventional chromatographic techniques with asialoglycophorin AN-Sepharose CL-4B affinity chromatography. Purification steps were followed by increase of specific activity. 2. Homogeneity of the purified lectin was demonstrated by HPLC and SDS-PAGE. The purified lectin was a glycoprotein with 11.4% carbohydrate and relatively high percentages of serine, threonine and aspartic acid residues and had a Mw of 120,000 Da. 3. This lectin agglutinated human N and MN erythrocytes, but did not agglutinate M erythrocytes. Hemagglutination of the lectin was inhibited by glycophorin AN and N-active sialoglycopeptide released from human N erythrocytes by treatment with Pronase or trypsin. However, it was not inhibited by any of mono- and di-saccharides, ABH-active glycoproteins, glycophorin AM and M-active sialoglycopeptide liberated from human M erythrocytes by treatment with Pronase or trypsin.

Amino Acids↗
PubMed1990

Isolation and characterization of blood group N antigen precursor glycoproteins with Thomsen-Friedenreich (T) activity, N antigen precursor glycoproteins and T-active glycoproteins from cyst fluids of malignant ovarian clear cell carcinoma.

1. Two perchloric acid-soluble glycoprotein fractions from cyst fluids of 2 patients with ovarian clear cell carcinoma in malignant were subjected to a systematic affinity chromatography using Vicia unijuga lectin-Cellulofine column and Arachis hypogaea lectin-Cellulofine column and separated into four glycoproteins, blood group N antigen precursor glycoprotein with Thomsen-Friedenreich (T) activity, N antigen precursor glycoprotein, T-active glycoprotein and serologically inactive glycoprotein, respectively. 2. These serologically active glycoproteins isolated in yields of 0.3-3.3% of PASFs, were proved to be mucin-type glycoproteins with Mw of 509,000-2,772,000 Da and contained 33.9-81.7% carbohydrates.

Acetylgalactosamine↗
PubMed1990

Separation and biochemical characterization of blood group N antigen precursor glycoproteins with Thomsen-Friedenreich (T) activity, T-active glycoproteins and N antigen precursor glycoproteins from ascites of primary ovarian cancer patients.

1. Three perchloric acid-soluble fractions from ascites of three primary ovarian cancer patients were subjected to Sephacryl S-300 gel filtration, respectively, and three Fr. 1 which were eluted in the vicinity of void volume as minor fractions, were then separated by a systematic affinity chromatography using Vicia unijuga lectin-Sepharose CL-4B column and Arachis hypogaea lectin-Sepharose CL-4B column into three glycoproteins, blood group N antigen precursor glycoprotein with Thomsen-Friedenreich (T) activity, T-active glycoprotein and N antigen precursor glycoprotein, respectively. 2. These nine glycoproteins separated in yields of 0.1-1.3 mg per 100 ml of ascites, were demonstrated to be mucin-type glycoproteins with Mw of 1,791,000-4,921,000 and contained 33.8-56.1% carbohydrates.

Amino Acids↗
PubMed1990

Altered synthesis of renin in patients with insulin-dependent diabetes: plasma prorenin as a marker predicting the evolution of nephropathy.

Plasma active renin (PARC) and plasma total renin (PTRC) were measured in 72 patients with childhood-onset IDDM and 37 control subjects in the supine posture. The diabetic patients were divided into three groups: group A, 55 patients with normoalbuminuria; group B, 11 patients with microalbuminuria; and group C, 6 patients with overt proteinuria. The levels of PTRC were 125 +/- 51, 240 +/- 124 and 580 +/- 285 ng/l in groups A, B and C, respectively; all of which were significantly higher than 114 +/- 33 ng/l in the control subjects. On the other hand, the ratios of plasma active to total renin, ARC/TRC, were 18.1 +/- 12.5, 10.7 +/- 6.7, and 2.9 +/- 1.4% in groups A, B and C, respectively; all of which were in turn significantly lower than 24.8 +/- 8.7% in the control subjects. Among the diabetic groups, PTRC became higher and ARC/TRC became lower in conjunction with the degree of albuminuria. The acute increments of PARC and PTRC during a standing load test were subsequently observed in 7 patients of group A, 5 of group B, 4 of group C, 13 patients with non-diabetic glomerulonephritis, and 6 control subjects. The ratios of increments of PARC to that of PTRC, delta ARC/delta TRC, were 48.3 +/- 22.3, 35.1 +/- 10.4 and 8.4 +/- 8.1% in groups A, B, C, respectively; all of which were significantly lower than 84.2 +/- 48.6% in the control subjects. Patients with non-diabetic glomerulonephritis showed, to a lesser degree, low ratio of delta ARC/delta TRC (60.4 +/- 37.9%) in conjunction with higher level of PTRC (249 +/- 89 ng/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Plasma active and inactive renin concentrations in children.

Plasma active and inactive renin concentrations (PARC and PIRC) were measured by immunoradiometric assay. Age-related changes in PARC, PIRC and the ratio of PARC/PIRC were studied in 78 normal children, age 1 month to 15 years. The effects of upright position for 15 min were also investigated in 7 postmenarcheal girls. PARC and PIRC in infants were significantly higher than in older children and their ratio of PARC/PIRC was significantly lower than in prepubertal children. During puberty, PARC, PIRC and their ratio were higher in premenarcheal girls than in postmenarcheal girls. In the upright position, PARC, PIRC and the ratio were increased significantly. These finding suggest that: (1) the production of inactive renin is increased but the activation of renin may be lowered in infants; (2) the activation of renin is affected by the menstrual cycle, and (3) the production and activation of renin are increased during short term standing.

Adolescent↗
PubMed1990

[Some chemical and serological properties of perchloric acid-soluble glycoproteins separated from ascitic fluid of a patient with metastatic omentum tumor from ovarian cancer].

One mol perchloric acid-soluble fraction (PASF) obtained from ascitic fluid of a patient (blood group B) with metastatic omentum tumor from ovarian cancer was a glycoprotein fraction containing 35.4% carbohydrate and exhibited A, B and Thomsen-Friedenreich (T) activities. This fraction was separated into three fractions, Frs. 1-3, by a gel filtration with Bio-Gel A-1.5 m column. Among these fractions, Fr. 1 which was obtained in a 5.5% yield to PASF, was a glycoprotein fraction with a high molecular weight, 23.3% carbohydrate and A, B and T activities. Other minor fraction, Fr. 2, and the major fraction, Fr. 3, contained 43.2% and 43.9% carbohydrate, but did not show A, B and T activities, respectively.

ABO Blood-Group System↗
PubMed1990

[Separation of Thomsen-Friedenreich (T) antigen and N antigen precursor glycoproteins from perchloric acid-soluble fraction of cyst fluid of human ovarian clear cell carcinoma and their some chemical and serological properties].

One M perchloric acid-soluble fraction separated from cyst fluid of a patient (blood group AB) with ovarian clear cell carcinoma in malignant was subjected to Sephacryl S-200 gel filtration and Fraction 1 which was eluted at void volume, reacted with both of the lectins of Vicia unijuga and Arachis hypogaea. This fraction was then separated into 6 fractions (DEAE-Frs. 1-6) in a DEAE-Sephacel column chromatography. DEAE-Frs. 3-6 were sugar-rich glycoprotein fractions which contained galactose and N-acetylglucosamine in remarkably high percentages, respectively. Reactivities against various hemagglutinins of these four fractions suggest that DEAE-Fr. 3 is a Thomsen-Friedenreich (T) glycoprotein fraction with AB activity and weak N antigen precursor activity and DEAE-Fr. 4 is an N antigen precursor glycoprotein fraction with AB activity and weak T activity.

Adenocarcinoma↗
PubMed1990

[Changes in thyroid function during ACTH therapy in patients with infantile spasms].

Serum triiodothyronine (T3), free T3, thyroxine (T4) and free T4 levels were measured before and immediately after daily ACTH-Z therapy (0.01 mg/kg/day, 1-2 weeks) for patients with 9 cases of infantile spasms and one case of myoclonus epilepsy. In some of them, serum reverse T3 (rT3) and thyroxine binding globulin (TBG) levels were also measured. All patients became seizure free after ACTH-Z therapy. Before ACTH-Z therapy, all of the hormone levels were within normal limits. Serum T3 and free T3 levels were markedly decreased after daily ACTH-Z therapy, and serum T4, free T4 and TBG levels were moderately decreased after the therapy. 1-6 weeks after the daily treatment, all of these hormone levels returned to pretreatment levels. Serum rT3 levels did not change after ACTH-Z therapy. These results suggest that the effect of long-term daily ACTH-Z therapy is very critical to the immature brain, and conventional ACTH-Z therapy has to be reconsidered.

Adrenocorticotropic Hormone↗
PubMed1990

Extracellular matrix phenotype of rat mesangial cells in culture. Biosynthesis of collagen types I, III, IV, and V and a low molecular weight collagenous component and their regulation by dexamethasone.

Rat glomerular cells were cultured in vitro to evaluate their collagen phenotype. The enriched epithelial cell population that grew out from glomeruli in the initial stages of culture primarily synthesized type IV collagen. By 14 days, mesangial cell proliferation occurred with a coordinate change in collagen phenotype, after which time these cells mainly synthesized type I collagen and lesser amounts of types III, IV, and V collagens. In addition to the standard collagens, mesangial cells synthesized and accumulated in their extracellular matrix a small molecular weight collagenous protein that accounted for 16.6% of the total radioactivity incorporated into extracellular matrix proteins. This short-chain collagen, with an approximate molecular mass of 70,000 (70 kd), appears to be a unique product of mesangial cells. Collagen biosynthesis by the mesangial cells was down-regulated by dexamethasone in a time- and dose-dependent manner. Treatment with 10(-6) mol/L dexamethasone reduced synthesis of type I and type IV collagens by about 37% and 24%, respectively. Steady-state levels of the corresponding procollagen messenger RNAs were diminished in dexamethasone-treated mesangial cells. This effect of glucocorticoid was found to be specific because dexamethasone did not affect biosynthesis and secretion of noncollagenous proteins.

Animals↗
PubMed1989

Autoimmune sequence of streptococcal M protein shared with the intermediate filament protein, vimentin.

The crossreactivity of antibodies against a renal autoimmune epitope of Streptococcus pyogenes M protein with glomerular mesangial cells was investigated. The antibodies directed against the amino acid sequence Ile-Arg-Leu-Arg of the nephritogenic type 1 M protein reacted in a fibrillar pattern with mesangial cells cultured from isolated glomeruli. In Western blots of urea-extracted mesangial proteins, the antibodies reacted with a 56-kD protein. Monoclonal and polyclonal antibodies identified the 56-kD mesangial protein as vimentin. Two synthetic peptides of human vimentin containing the sequence Arg-Leu-Arg reacted with the autoimmune antibodies raised against a streptococcal M protein peptide. These results provide evidence that the intermediate filament protein vimentin shares autoimmune epitopes with streptococcal M protein.

Amino Acid Sequence↗
PubMed1989

Identification of a novel nifH-like (frxC) protein in chloroplasts of the liverwort Marchantia polymorpha.

The frxC gene, one of the unidentified open reading frames present in liverwort chloroplast DNA, shows significant homology with the nifH genes coding for the Fe protein, a component of the nitrogenase complex (Ohyama et al., 1986, Nature 322: 572-574). A truncated form of the frxC gene was designed to be over-expressed in Escherichia coli and an antibody against this protein was prepared using the purified product as an antigen. This antibody reacted with a protein in the soluble fraction of liverwort chloroplasts, which had an apparent molecular weight of 31,000, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in good agreement with a putative molecular weight of 31,945 deduced from the DNA sequence of the frxC gene. In a competitive inhibition experiment, the antigenicity of this protein was indicated to be similar to that of the over-expressed protein in E. coli. Therefore, we concluded that the frxC gene was expressed in liverwort chloroplasts and that its product existed in a soluble form. The molecular weight of the frxC protein was approximately 67,000, as estimated by gel filtration chromatography, indicating that the frxC protein may exist as a dimer of two identical polypeptides analogous to the Fe protein of nitrogenase. The results obtained from affinity chromatography supported the possibility that the frxC protein, which possesses a ATP-binding sequence in its N-terminal region that is conserved among various other ATP-binding proteins, has the ability to bind ATP.

Adenosine Triphosphate↗
PubMed1989

Type IV collagen synthesis by cultured mouse keratinocytes (Pam cells).

The collagens synthesized by Pam cells were biochemically characterized. The collagen in the cell layers was identified as type IV collagen by immunoprecipitation with type IV collagen specific antibody. The apparent molecular weights were 180 Kd and 175 Kd, which converted to major (160 Kd) and several minor smaller fragments with pepsin treatment. The ratios of 3-hydroxyproline/4-hydroxyproline and 4-hydroxyproline/proline in the 160 Kd polypeptide were 0.11 and 1.18, respectively. The result shows that Pam cells are able to produce type IV collagen whose biochemical characteristics are similar to those from other epithelial cells. In the kinetic study, the synthesis of type IV collagen reached its maximum level rapidly on the 1st day after seeding, suggesting that type IV collagen may play a role in cell attachment and proliferation.

Animals↗
PubMed1989

[Some chemical and serological properties of non-dialysable fractions of human seminal plasmas].

Some chemical and serological properties of water-soluble and undialysable fraction (WSF) and water-insoluble and undialysable fraction (WISF) of human seminal plasmas were studied. Both of the fractions contained proteins as the main components and also carbohydrates as minor components, and each fraction gave 9 bands which were stained with the Periodate-Schiff and/or Coomassie brilliant blue reagents on sodium dodecyl sulfate-polyacrylamide slub gel electrophoresis. WSF reacted with 17 of 19 hemagglutinins, whereas WISF reacted with 12 of them. Although WSF and WISF did not react with anti-M and -N sera respectively, both of the fractions reacted with the anti-N lectins of Vicia graminea and V. unijuga and also with Arachis hypogaea anti-T (Thomsen-Friedenreich) lectin. Perchloric acid-soluble fractions separated from a large number of human intact organ tissues and serum did not react with the above-mentioned 5 hemagglutinins. In double immuno-diffusion, both of the fractions interacted with rabbit anti-WSF serum to form 4 precipitation lines.

Antigen-Antibody Reactions↗
PubMed1989

Plasma active renin concentration in children.

In normal children aged one month to 16 years, the plasma active renin concentration (PARC) was measured with a renin immunoradiometricassay (IRMA) kit, and was compared with plasma renin activity (PRA). The IRMA for renin was found to be independent of the amount of renin substrate and not affected by the dilution of plasma samples, and was therefore proved to be a simple and reliable method. PRA measured in non-diluted plasma samples correlated well with PARC. In the age-related change, PARC in infants was significantly higher than that in older children. In infants, PARC was markedly higher in the crying state than that in the non-crying state. In normal children aged 7 to 11 years, PARC was significantly increased in the upright position compared to the supine position. These findings suggest that a hyperresponse of PARC to acute stress during blood sampling may cause an increase in active renin secretion in infants, and that stimulation by short-term standing may accelerate the activation of inactive renin or the release of active renin.

Adolescent↗
PubMed1989

[Changes in anterior pituitary function during ACTH therapy of patients with infantile spasms].

Serum cortisol, prolactin (PRL), TSH, GH, LH and FSH levels were measured before and immediately after daily ACTH-Z therapy (0.01 mg/kg/day, 1-2 weeks) for 5 patients with infantile spasms and one patient with myoclonus epilepsy. Total number of ACTH-Z therapy were 8 times, and all patients became seizure free after ACTH-Z therapy. In 6 occasions, TRH, LH-RH and insulin tolerance tests were performed before and after daily ACTH-Z therapy. Serum cortisol levels were significantly increased after daily ACTH-Z therapy but all other hormone levels were significantly decreased. In TRH and LH-RH tolerance tests, peak levels and increments of PRL, LH and FSH were significantly decreased after daily ACTH-Z therapy and those of TSH were mildly decreased. In one case insulin tolerance test revealed an adequate decrease of blood glucose before and after ACTH-Z therapy, and there was a poor GH response after ACTH-Z therapy. Daily ACTH-Z therapy was thought to suppress secretion of anterior pituitary hormones.

Child, Preschool↗
PubMed1988

A nicked group II intron and trans-splicing in liverwort, Marchantia polymorpha, chloroplasts.

The chloroplast gene rps12 for ribosomal protein S12 in a liverwort, Marchantia polymorpha, is split into three exons by two introns, one of which (intron 1) is discontinuous. Exon 1 of rps12 for the N-terminal portion of the S12 protein is far from exons 2 and 3 for the C-terminal portion on the opposite DNA strand. S1-nuclease protection analysis and Northern hybridization with RNA isolated from the liverwort chloroplasts showed that: (i) the exons 1 and 2-3 of the rps12 gene with the neighboring genes were transcribed separately, (ii) the trans-splicing of intron 1 occurred after the processing of two primary transcripts to two pre-mRNAs, and (iii) there was no particular order for the splicing of intron 1 (trans) and intron 2 (cis) in the rps12 gene. We propose a bimolecular interaction model for trans-splicing by assuming that intermolecular base pairings between two pre-mRNAs result in the formation of the structure typical of group II introns except for disruption in the loop III region. This structure could be constructed in intron 1 of tobacco rps12 gene.

Base Sequence↗
PubMed1988

Structure and organization of Marchantia polymorpha chloroplast genome. I. Cloning and gene identification.

We have determined the complete nucleotide sequence of chloroplast DNA from a liverwort, Marchantia polymorpha, using a clone bank of chloroplast DNA fragments. The circular genome consists of 121,024 base-pairs and includes two large inverted repeats (IRA and IRB, each 10,058 base-pairs), a large single-copy region (LSC, 81,095 base-pairs), and a small single-copy region (SSC, 19,813 base-pairs). The nucleotide sequence was analysed with a computer to deduce the entire gene organization, assuming the universal genetic code and the presence of introns in the coding sequences. We detected 136 possible genes. 103 gene products of which are related to known stable RNA or protein molecules. Stable RNA genes for four species of ribosomal RNA and 32 species of tRNA were located, although one of the tRNA genes may be defective. Twenty genes encoding polypeptides involved in photosynthesis and electron transport were identified by comparison with known chloroplast genes. Twenty-five open reading frames (ORFs) show structural similarities to Escherichia coli RNA polymerase subunits, 19 ribosomal proteins and two related proteins. Seven ORFs are comparable with human mitochondrial NADH dehydrogenase genes. A computer-aided homology search predicted possible chloroplast homologues of bacterial proteins; two ORFs for bacterial 4Fe-4S-type ferredoxin, two for distinct subunits of a protein-dependent transport system, one ORF for a component of nitrogenase, and one for an antenna protein of a light-harvesting complex. The other 33 ORFs, consisting of 29 to 2136 codons, remain to be identified, but some of them seem to be conserved in evolution. Detailed information on gene identification is presented in the accompanying papers. We postulated that there were 22 introns in 20 genes (8 tRNA genes and 12 ORFs), which may be classified into the groups I and II found in fungal mitochondrial genes. The structural gene for ribosomal protein S12 is trans-split on the opposite DNA strand. The universal genetic code was confirmed by the substitution pattern of simultaneous codons, and by possible codon recognition of the chloroplast-encoded tRNA molecules, assuming no importation of tRNA molecules from the cytoplasm. The nucleotide residue A or T is preferred at the third position of the codons (G+C, 11.9%) and in intergenic spacers (G+C, 19.5%), resulting in an overall G+C content that is low (28.8%) throughout the liverwort chloroplast genome. Possible gene expression signals such as promoters and terminators for transcription, predicted locations of gene products, and DNA replicative origins are discussed.

Base Sequence↗