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Biomedical subjects

Y Natori

Publications and source records attributed to Y Natori.

At least 109 records · Page 6Linked to original sources
PubMed1992

In vitro self-assembly of the S layer subunits from Clostridium difficile GAI 0714 into tetragonal arrays.

Regularly arrayed surface component (S layer) of Clostridium difficile strain GAI 0714 was isolated with 4 M guanidine hydrochloride from the cell wall of the organism, and examined for self-assembly in vitro. The S layer was composed of two different protein subunits with molecular weights of 32 kDa and 45 kDa. Optical diffraction analysis revealed that the morphological units of both native and self-assembled S layer were essentially identical and composed of a rhombus possessing each side of 8.1 nm and interior angle of 88 degrees. The self-assembly of S layer subunits were induced in the presence of divalent cations such as Ca2+ or Zn2+, but Ba2+ or monovalent cations including K+, Na+ and Li+ failed to induce self-assembly. These results suggest that Ca+2 or Zn+2 may act as bridges to link negatively charged surface subunits.

Bacterial Outer Membrane Proteins↗
PubMed1992

[Microsurgical anatomy of the region near the porus acusticus internus; arteries around the facial and acoustic nerves bundle].

The microsurgical anatomy of the cerebellopontine cistern around the porus acusticus was studied under the surgical microscope, using the heads of 20 cadavers. The relationships among the porus acusticus, facial and acoustic nerves, and neighboring arteries were noted carefully. The arteries were the meatal loop of the cerebellar artery, the internal auditory artery (I.A.A.), the subarcuate artery (S.A.), and the perforating artery (P. A.). The cerebellar arteries made the meatal loop and the arterial-nerve complex while they passed in front of the porus acusticus. Most of the cerebellar arteries were the main or rostral trunk of the AICA. The I.A.A. supplying the facial and acoustic nerves usually originated from the meatal segment of the cerebellar artery and ran into the anterior part of the porus acusticus to enter the internal auditory canal. The S. A. penetrating the subarcuate fossa made a common trunk with I. A. A. or branched from the cerebellosubarcuate artery. One recurrent P. A., a special type of the P. A., was usually present on each side. Since the artery ran between the nerve bundles of the facial and acoustic nerves, it could not be seen through the lateral suboccipital approach.

Arteries↗
PubMed1991

Management of syringomyelia associated with Chiari malformation: comparative study of syrinx size and symptoms by magnetic resonance imaging.

The authors reviewed the postoperative alteration of symptoms and syrinx size by magnetic resonance imaging (MRI) in 14 consecutive patients with syringomyelia associated with Chiari malformation. The patients were treated according to our treatment regimen and were divided into five groups according to operative modalities: (1) only foramen magnum decompression (D) for small syrinx; (2) D with ventriculoperitoneal (VP) shunt for small syrinx with hydrocephalus; (3) D with syringosubarachnoid (SS) shunt or (4) D with syringoperitoneal (SP) shunt for large syrinx; and (5) only VP shunt for syrinx with hydrocephalus and atlantoaxial dislocation, respectively. From the preoperative and postoperative sagittal MR images, the areas of the spinal cord and syrinx were measured by a digitizer and the syringo-cord (S-C) ratio was calculated. Out of 14 patients, 12 showed a reduction of syrinx size and a stabilization or improvement of symptoms after surgery. In the other two patients, the syrinx size did not change and their symptoms worsened. Magnetic resonance imaging follow-up showed that foramen magnum decompression without shunt is effective for patients with a small syrinx below 35% of the S-C ratio, and foramen magnum decompression with shunt was effective for patients with a large syrinx over 35% of the S-C ratio, but there was no significant difference between the SS and SP shunt group.

Adolescent↗
PubMed1991

Monoclonal-antibody-based enzyme-linked immunosorbent assay for HMG 2b nonhistone protein in chick liver.

Monoclonal antibodies were prepared against the high mobility group (HMG) protein 2b from chick liver chromatin and a monoclonal-antibody-based enzyme-linked immunosorbent assay (ELISA) was developed for chick HMG 2b. The sensitivity of the assay is about ten times that of the previously described radioimmunoassay and solid-phase enzyme immunoassay for HMG proteins. With the use of ELISA technique, the amount of HMG 2b (micrograms protein/mg DNA) in the livers of 1-day old and 70-day old chicks was found to be 2.56 +/- 0.4, and 1.20 +/- 0.2, respectively. The age-dependent change in the level of HMG proteins probably reflects changes in the functional state of chromatin during ageing.

Animals↗
PubMed1991

Effect of pyridoxine-deficiency on degradation of cytosolic aspartate aminotransferase in rat liver lysosomes.

Highly purified lysosomes were isolated from the livers of control and pyridoxine-deficient rats. The calculation of the lysosomal protein contents indicated that the livers of both groups of rats contain virtually the same amounts of the lysosomal proteins (12.0 and 13.0 mg lysosomal proteins/g liver proteins for the control and pyridoxine-deficient rats, respectively). The immunoblotting of the lysosomal proteins with anti-cytosolic aspartate aminotransferase (cAspAT) showed 46 kDa band, corresponding to the subunit molecular weight of cAspAT, as well as the bands representing degradative intermediates of cAspAT. The relative amounts of the immuno-reactive substances were estimated by scanning the immuno-stained bands and measuring the densitometric tracings. It was found that the lysosomes in the pyridoxine-deficient rat liver contain almost twice as much cAspAT and its degradative intermediates as those in the control rat liver. On the basis of these observations, it was concluded that the increased rate of degradation of cAspAT in the liver of the pyridoxine-deficient rats is brought about by the increased rate of sequestration of cAspAT into lysosomes.

Animals↗
PubMed1990

Immunochemical detection of 'platelet type' phospholipase A2 in the rat.

Polyclonal antibodies were raised against rat platelet phospholipase A2. One of them, designated as R377 was prepared by immunizing a rabbit with the intact enzyme. The other antibody, designated as R385, was prepared by immunizing with the enzyme treated with 2-mercaptoethanol. The antibody R377 bound to rat platelet phospholipase A2 almost exclusively, while the antibody R385 reacted not only with rat platelet phospholipase A2 but with the enzymes obtained from snake venom or mammalian pancreas. The antibody R377 bound to the non-reduced rat platelet phospholipase A2 bearing intact intramolecular disulfide bonds, but not to the reduced enzyme. In contrast, the antibody R385 reacted with both non-reduced and reduced enzymes. R377 may recognize the conformational structure of the enzyme. Both antibodies inhibited the enzyme activity. The antibody R377, but not R385, interfered with the interaction of the enzyme with heparin, which is one of the characteristic properties of rat platelet phospholipase A2. The antibody R377 reacted with phospholipases A2 of bone-marrow cells and of peritoneal exudated cells prepared from caseinate-treated rats, indicating that some myeloid cells other than platelets also contain 'platelet type' phospholipase A2. An immunochemical method for measurement of rat 'platelet type' phospholipase A2 was developed. The sensitivity of this method was 10 ng/ml of phospholipase A2 in the preparation. One of the advantages of the present immunochemical method is that the measurement was not affected by the presence of an endogenous inhibitor(s) of enzymatic activity.

Animals↗
PubMed1990

Effect of gastric distention on RNA synthesis in neonatal chick liver.

RNA synthesis in the nuclei of liver from newly hatched chicks was enhanced 1.25 fold at 10 min after intragastric administration of water. Differential inhibition of RNA synthesis by alpha-amanitin indicated that the enhancement mainly represented rRNA synthesis; the synthesis of mRNA and tRNA was scarcely affected. Enhanced RNA synthesis was accompanied by greater susceptibility of nuclei to digestion by micrococcal nuclease, indicating that the chromatin structure was modified. It was further shown that the "water effect" was mimicked by distention of the stomach by raising the pressure in the intragastric balloon. Since the prior administration of atropine abolished the "water effect", the enhancement of hepatic RNA synthesis may be mediated by hepatic nervous system.

Age Factors↗
PubMed1990

Magnetic resonance imaging of experimental rat brain tumors: histopathological evaluation.

Using RG-C6 glioma-transplanted rats, we studied precontrast and postcontrast magnetic resonance imaging, extravasation of Evans blue, and histology. In all rats, tumor was enhanced with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). The necrotic portion in the tumor, however, was not enhanced. Hemorrhage and hydrocephalus were clearly visualized on both the precontrast and postcontrast images. Blood-brain barrier-disrupted areas stained with Evans blue and areas enhanced with Gd-DTPA on magnetic resonance imaging were nearly consistent. It is suggested that the mechanism of brain tumor enhancement with Gd-DTPA on magnetic resonance imaging is simply related to the degree of alteration of the blood-brain barrier. The Gd-DTPA-enhanced magnetic resonance imaging, even with low magnetic field, is useful for the evaluation of size, shape, and location of experimental rat brain tumors.

Animals↗
PubMed1990

Genetic transformation of Lactobacillus casei by electroporation.

Lactobacillus casei IAM1045 was transformed with a plasmid pAM beta 1-1, a tra deleted derivative of pAM beta 1, by electroporation. Effective transformation was achieved in electroporation buffers of a wide range of pH values, and in all phases of cell growth tested, with highest frequency in the early log phase. Polyethylene glycol increased the transformation frequency, whereas divalent cations such as Mg2+, Ca2+ and Mn2+ at 0.25 mM decreased the frequency by 2 to 3 orders. Highly efficient transformation of approximately 10(-4)/viable cell was achieved under optimal conditions. A plasmid harboring the trpD, C, F, B and A genes from L casei RNL7 was introduced by electroporation into tryptophan auxotrophic L casei JCM1053. The resulting transformant was found to express the trp genes introduced.

Calcium↗
PubMed1990

Nucleotide sequences and genomic constitution of five tryptophan genes of Lactobacillus casei.

Five trp genes, trpD, trpC, trpF, trpB, and trpA, of Lactobacillus casei were cloned by transformation of tryptophan auxotrophic mutants of the respective trp genes in Escherichia coli. These trp genes appear to constitute an operon and are located in the above order in a segment of DNA of 6,468 base pairs. The entire nucleotide sequence of this DNA segment was determined. Five contiguous open reading frames in this segment can encode proteins consisting of 341, 260, 199, 406, and 266 amino acids, respectively, in the same direction. The amino acid sequences of these proteins exhibit 25.5-50.2% homology with the amino acid sequences of the corresponding trp enzymes of E. coli. Two trp genes, trpC and trpF, from L. casei can complement mutant alleles of the corresponding genes of E. coli. However, neither the trpA gene nor the trpB gene of L. casei can complement mutations in the E. coli trpA gene and the trpB gene, respectively, suggesting that the protein products of the L. casei and E. coli trpA and trpB genes, respectively, cannot form heterodimers of tryptophan synthetase with activity. Other features of the coding and flanking regions of the trp genes are also described.

Amino Acid Sequence↗
PubMed1990

[CA 19-9 in patients with benign pulmonary diseases].

Although serum CA 19-9 is considered to be a useful and specific tumor marker for pancreatic cancer, some patients with benign pulmonary diseases show elevated serum CA 19-9 levels. We measured serum CA 19-9 levels of 156 patients with benign pulmonary diseases (55 with asbestosis, 11 with bronchial asthma, 32 with bronchiectasis, 16 with idiopathic pulmonary fibrosis (IPF), 13 with healed pulmonary tuberculosis (HPT) and 29 other benign diseases). The percentage of patients with positive serum CA 19-9 was 42.3% (14.5% in asbestosis, 27.3% in bronchial asthma, 59.4% in bronchiectasis, 81.3% in IPF, 61.5% in HPT and 51.7% in others). In some patients, serum CA 19-9 levels were as high as those found in malignant gastrointestinal diseases. Serum CA 19-9 levels correlated well with disease activity. Immunohistochemically, CA 19-9 was expressed in mucous cells of the bronchial gland and surface of the bronchiolar surface epithelium cells in benign pulmonary disease. Gel filtration study suggested some difference in molecular weight between the serum CA 19-9 antigen of lung cancer and that of benign pulmonary diseases. It is suggested that serum CA 19-9 increases in the case of hyperplasia of the bronchiolar epithelium cells or the mucous cells of the bronchial gland. We conclude that benign pulmonary disease is one of the factors that affect serum CA 19-9 levels.

Aged↗
PubMed1990

[The effects of diclofenac sodium on thyroid function tests in vivo and in vitro].

In order to investigate the effects of the non-steroidal antiinflammatory drug, diclofenac sodium on thyroid function, 8 male and 2 female volunteers were given single dose of 50 mg diclofenac sodium. Ninety minutes after the administration of the drug, the concentrations of total T 3, total T 4 and free T 4 were decreased significantly, but the concentrations of free T 3 and the levels of T 3 uptake, % free T 3 and % free T 4 were increased. When diclofenac sodium was added to serum in vitro, the levels of free T 3, free T 4 and T 3 uptake were increased. These results showed that diclofenac sodium inhibited the binding of T 3 and T 4 competitively to the binding protein. The apparent decline in the concentrations of total T 3 and total T 4 after diclofenac sodium administration suggested that the drug altered distribution and metabolism of T 3 and T 4 mainly by increasing their free forms.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Nephritogenic glycoprotein. XIII. Isolation and its immunochemical characterization of the antigenic substance of membranous glomerulonephritis induced by a single injection of crude nephritogenoside in homologous animals.

Studies on the immunochemical characterization were made on the antigenic substance of membranous glomerulonephritis (MG) that is induced, in homologous animals, by a single footpad injection of rat crude nephritogenoside (CNG). In rats injected with rat CNG, typical MG with immunofluorescent granular pattern (immune complex type nephritis) was produced 3-4 months after the injection. Since CNG nephritis is a model which induces MG only in homologous animals, the development of MG in this model should be explained by antigen-autoantibody immune complex mechanism. Thus, the features of the antigenic substance contained in CNG was immunochemically investigated, utilizing the serum (autoantibody) of rats with MG as well as rabbit antiserum to rat tubular brush border antigen (FXIA) (heteroantibody). As a result, two different fractions (fr. 31 and fr. 36) were separated from the antigenic substance contained in CNG: that is, fr. 31 reacts only with rabbit antiserum to rat tubular brush border antigen (FXIA) (heteroantibody) but does not react with the serum (autoantibody) of rats with MG. Fr. 36 does not react with rabbit antiserum to FXIA (heteroantibody) and reacts only with the serum (autoantibody) of rats with MG (which was induced by a single footpad injection of CNG or soluble FXIA). These results suggest immunologically that fr. 36 is the main antigen responsible for the development of MG which is induced in homologous animals by a single footpad injection of CNG.

Animals↗
PubMed1988

Degradation of aspartate aminotransferase in rat liver lysosomes.

Highly purified lysosomes from the normal and leupeptin-treated rat livers were subjected to immunoblot analysis using antibodies against cytosolic and mitochondrial isozymes of aspartate aminotransferase (cAspAT and mAspAT). In the case of cAspAT (subunit M.W. = 46K), the leupeptin-treated lysosomes showed a major band of 46K and a minor band of 36K while normal lysosomes showed a major band of 36K and a minor band of 41K. In the case of mAspAT (subunit M.W. = 44K), the leupeptin-treated lysosomes showed a 44K band and the normal lysosomes showed a 40K band. These observations suggest that both cAspAT and mAspAT are sequestered into lysosomes with the original subunit molecular weights and are degraded in the lysosomes by way of sequential formation of relatively stable intermediates with distinct molecular weights.

Animals↗
PubMed1988

The structure of nephritogenoside. A nephritogenic glycopeptide with alpha-N-glycosidic linkage.

Nephritogenoside is a glycopeptide with the ability to induce chronic progressive glomerulonephritis (end stage kidney) in homologous animals, by a single footpad injection. This substance contains a novel carbohydrate-peptide linkage, i.e. the trisaccharide (3 glucose residues) chain is alpha-N-glycosidically linked to the polypeptide chain through the amido nitrogen of an asparagine residue at the N-terminal. It was found that the peptide portion of nephritogenoside is composed of twenty-one amino acids (Asn1-Pro-Leu-Phe-Gly5-Ile-Ala-Gly-Glu-Asp10-Gly-Pro-Thr-Gly-Pr o15-Ser-Gly-Ile- Val-Gly20-Gln21) and that the peptide portion has a repeated Gly-X-Y structure.

Amino Acid Sequence↗
PubMed1988

Characterization and promoter selectivity of Lactobacillus acidophilus RNA polymerase.

DNA-dependent RNA polymerase has been purified from gram-positive Lactobacillus acidophilus and found to be composed of 4 protein subunits, alpha, beta, beta', and sigma, with molecular weights of 40,000, 150,000, 135,000, and 45,000 kD, respectively, estimated on the basis of SDS-polyacrylamide gel electrophoresis. The purified enzyme exhibits optimal activity in the presence of Mn2+, while Mg2+ shows only a slight effect. The L. acidophilus enzyme transcribes several Escherichia coli promoters examined so far, such as promoters of trp operon, lacUV5, and bla P3 from pBR322, whereas it lacks the ability to recognize bla P1 and tet P2 promoters from pBR322. Thus, the specificity of L. acidophilus RNA polymerase in recognizing the promoters is somehow different from that of the E. coli enzyme. By means of an in vitro transcription assay system for L. acidophilus RNA polymerase, 2 promoters have been identified in the DNA of an L. acidophilus cryptic plasmid (pRNL5). These promoters possess nucleotide sequences in the -10 region similar to the consensus sequence for the E. coli promoters.

Animals↗