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Biomedical subjects

T Miyata

Publications and source records attributed to T Miyata.

At least 631 records · Page 35Linked to original sources
PubMed1986

The amino acid sequence of the procoagulant- and prothrombin-binding domain isolated from staphylocoagulase.

The primary structure of the procoagulant- and prothrombin-binding domains, the 43- and 30-kDa fragments previously isolated from staphylocoagulase, has been determined by sequencing peptides derived from various chemical (CNBr and 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine) and enzymatic (trypsin and alpha-chymotrypsin) cleavages. Carboxypeptidase Y was also used to deduce the COOH-terminal sequence. The 43-kDa fragment contained 324 amino acids and had a calculated molecular weight of 38,098. It included the entire structure of the 30-kDa fragment located in the COOH-terminal portion (positions 126-324). The 43-kDa fragment had an unusual amino acid composition based on the sequence, in which the sum of Asp (28 residues), Asn (22), Glu (35), Gln (9), and Lys (52) residues accounted for more than 45% of the total. In addition, the frequent occurrence of repetitions of the various kinds of dipeptides was found along the whole sequence. Structural comparison of the NH2-terminal portion of the 43-kDa fragment of staphylocoagulase with that of streptokinase did not reveal any obvious sequence homologies. There was also no sequence homology with that of trypsin, alpha-chymotrypsin, and elastase.

Amino Acid Sequence↗
PubMed1986

A simple method to heparinize biological materials.

A new method was developed inducing antithrombogenicity to biologic materials. A basic protein, protamine, was used to increase heparin binding to collagenous materials. Protamine sulfate solution was poured into a collagen-rich material (porcine ureter). The protamine adsorbed to the collagen was then cross-linked to the material by glutaraldehyde. The collagen-protamine complex was then interacted with a heparin solution to ionically bind heparin to the material. The amount and the distribution of the bound heparin can be controlled by changing the protamine fixation to the material. A heparinized porcine ureter as a vascular substitute showed excellent antithrombogenicity in experimental animal studies. This method is expected to be used as method for developing antithrombogenic artificial organs, and as a method for the development of antiadhesive membranes.

Animals↗
PubMed1986

Plasma endotoxin levels and functions of peripheral granulocytes in surgical patients with respiratory distress syndrome.

Plasma endotoxin levels and granulocyte functions (chemiluminescence and chemotaxis) were determined in fifty-two patients with postoperative sepsis. Seventeen had concurrent respiratory distress syndrome (RDS group) and the remaining thirty-five were free of the syndrome (non-RDS group). The plasma endotoxin concentrations were higher in the RDS group than in the non-RDS group (p less than 0.001). All nine patients with particularly high levels (greater than 80 pg) belonged to the RDS group. We noted a positive correlation in chemiluminescence (p less than 0.001, r = 0.67) and a negative correlation in chemotactic activity (p less than 0.001, r = 0.69). To determine whether endotoxin alters normal granulocyte functions in vitro, healthy granulocytes were treated by the endotoxin (E. coli 0111:B4). There was an increase in chemiluminescence and a decrease in chemotactic activity, as observed in vivo. Furthermore, normal granulocytes chemiluminescence was increased by pretreatment of RDS plasma showing high endotoxin levels in vitro (n = 4, p less than 0.05). Thus, endotoxin in the plasma probably plays an important role in marked changes in peripheral granulocyte functions in patients with respiratory distress syndrome.

Adult↗
PubMed1986

Torsion of the gallbladder.

A 77-year-old Japanese woman with torsion of the gallbladder was surgically treated. Perhaps because of its rarity, the diagnosis is seldom made clinically, the condition generally being recognized only at laparotomy. Discussed herein are the possibility of preoperative diagnosis of this condition and the usefulness of ultrasonotomography.

Aged↗
PubMed1986

Pipecolic acid enhancement of GABA response in single neurons of rat brain.

Using unit recording and microelectrophoresis, influence of pipecolic acid (PA), a major metabolite of lysine in the brain, on GABA and glycine responses was studied in the cerebral cortical and hippocampal pyramidal neurons of rats. With small currents, PA had no effect on the single neuron activities but enhanced GABA response without affecting glycine response. The finding provides a new evidence that PA may have a connection with central GABA system.

Action Potentials↗
PubMed1986

Two types of coagulogen mRNAs found in horseshoe crab (Tachypleus tridentatus) hemocytes: molecular cloning and nucleotide sequences.

The complete cDNA sequence coding for the coagulogen present in the horseshoe crab (Tachypleus tridentatus) hemocytes was determined. Clones carrying cDNA fragments for coagulogen were isolated from a cDNA library of the hemocyte mRNA using synthetic oligodeoxyribonucleotides as probes. The nucleotide sequence analyses of the cloned cDNAs revealed that the hemocyte coagulogen consists of 175 amino acids with 20 amino acids in a presegment, and that there are two types of mRNAs for coagulogen. The two mRNAs exhibited three nucleotide substitutions, two of which were in their protein-coding regions, resulting in two amino acid replacements. Subsequently, two molecular species of coagulogen, named coagulogens type I and type II, were identified by tryptic peptide mapping of the mature proteins isolated from the hemocyte lysate. These results suggest that the two types of coagulogens are first synthesized as preproteins and are incorporated into the granules that are abundantly present in the hemocytes with liberation of the signal peptides.

Amino Acid Sequence↗
PubMed1986

Complete amino acid sequence of NADH-cytochrome b5 reductase purified from human erythrocytes.

The complete amino acid sequence of soluble NADH-cytochrome b5 reductase purified from human erythrocytes was determined. The enzyme, which contained 8 methionine residues, was cleaved by cyanogen bromide. The resulting nine peptides were separated by gel filtration and purified further by high-performance liquid chromatography. The purified peptides were sequenced by automated Edman degradation. Three large CNBr peptides, residues 1-101, 109-151, and 169-231, were further fragmented with trypsin, Staphylococcus aureus V8 protease or a lysyl endopeptidase of Achromobacter lyticus. The peptides obtained from the tryptic digest of citraconylated FAD-depleted apoprotein completed the alignments of the other peptides. The enzyme was composed of 275 amino acid residues. The 4 functionally important cysteine residues were located in the COOH-terminal portion. The molecular weight of the protein was calculated to be 31,260 without FAD. A prediction of the secondary structure was made by the method of Chou and Fasman. The protein was hydrophilic as a whole (43% polarity), but some regions were rich in hydrophobic residues. From the sequence homology of this enzyme with the pyridine nucleotide-binding sites of other flavoproteins, three candidates for the FAD and NADH-binding domains were suggested.

Amino Acid Sequence↗
PubMed1986

Isolation and amino acid sequence of a peptide containing an epoxide-reactive residue from the thermolysin-digest of Scytalidium lignicolum acid protease B.

Scytalidium lignicolum acid protease B, a pepstatin-insensitive acid protease, was modified by 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) with the concomitant loss of its enzyme activity, and an EPNP-labeled peptide was isolated from the thermolysin-digest of the modified enzyme by HPLC. The amino acid sequence of the peptide was determined to be Ile-Leu-Glu-Thr-Gly, which corresponds to the sequence of residue Nos. 51-55 of the enzyme. The results of treatment of the labeled peptide with hydroxylamine suggested that the EPNP moiety is ester-linked to Glu53 of the enzyme. The amino acid sequence around Glu53 of the acid protease B showed high homology with those around the active site Asp residues of calf chymosin and porcine pepsin. These results show that it is highly possible that Glu53 of the acid protease B is one of the amino acid residues involved in its catalytic activity.

Amino Acid Sequence↗
PubMed1986

Difference in enzymatic properties between "staphylothrombin" and free alpha-thrombin.

Bacterial protein, staphylocoagulase, binds stoichiometrically to human prothrombin resulting in a coagulant complex, staphylothrombin. The enzymatic properties of staphylothrombin differ from those of alpha-thrombin in their substrate specificities toward natural and synthetic substrates, in addition to their interaction with protease inhibitors. In order to obtain information about the region of staphylocoagulase that interacts with human prothrombin, staphylocoagulase was cleaved by alpha-chymotrypsin. This limited alpha-chymotryptic cleavage of staphylocoagulase yielded three large fragments, fragments of 43, 30, and 20 kDa. The 43-kDa fragment exhibited a high affinity for human prothrombin (Kd = 1.7 nM), which is comparable to the affinity observed using intact staphylocoagulase (Kd = 0.46 nM). A complex of the 43-kDa fragment and prothrombin possessed both clotting and amidase activities essentially identical to those observed in a complex of intact staphylocoagulase and prothrombin. The 30-kDa fragment exhibited weaker affinity for prothrombin (Kd = 120 nM). While a complex of this fragment and prothrombin did not exhibit clotting activity, it nonetheless possessed a weak amidase activity. The 20-kDa fragment was found only to bind to prothrombin. The NH2-terminal sequence analyses of these fragments revealed that the 43-kDa fragment constitutes the NH2-terminal portion of staphylocoagulase, and contains the 30-kDa and 20-kDa fragments. It is therefore concluded that the functional region of staphylocoagulase for binding and activation of prothrombin is localized in the NH2-terminal region of the intact protein. The 43-kDa fragment contains 324 amino acids with a molecular weight of 38,098. The 43-kDa fragment has an unusual amino acid composition based on the sequence, in which the sum of Asp (28 residues), Asn (22), Glu (35), Gln (9), and Lys (52) residues accounts for more than 45% of the total residues. A comparison of the amino acid sequence of the 43-kDa fragment with that of streptokinase did not reveal any obvious sequence homology. There was also no sequence homology with those of trypsin, alpha-chymotrypsin, and elastase.

Binding Sites↗
PubMed1986

Nucleotide sequence of human endogenous retrovirus genome related to the mouse mammary tumor virus genome.

We determined the complete nucleotide sequence of the human endogenous retrovirus genome HERV-K10 isolated as the sequence homologous to the Syrian hamster intracisternal A-particle (type A retrovirus) genome. HERV-K10 is 9,179 base pairs long with long terminal repeats of 968 base pairs at both ends; a sequence 290 base pairs long, however, was found to be deleted. It was concluded that a composite genome having the 290-base-pair fragment is the prototype HERV-K provirus gag (666 codons), protease (334 codons), pol (937 codons), and env (618 codons) genes. The size of the protease gene product of HERV-K is essentially the same as that of A- and D-type oncoviruses but nearly twice that of other retroviruses. A comparison of the deduced amino acid sequences encoded by the pol region showed HERV-K to be closely related to types A and D retroviruses and even more so to type B retrovirus. It was noted that the env gene product of HERV-K structurally resembles the mouse mammary tumor virus (type B retrovirus) env protein, and the possible expression of the HERV-K env gene in human breast cancer cells is discussed.

Amino Acid Sequence↗
PubMed1986

[Effects of ambroxol on pulmonary surfactant--analysis of the fatty acid composition of phosphatidylcholine in the sputum and normal respiratory tract fluid in rabbits].

The mechanism of action of secretagogic expectorants (ex., ambroxol) has not been clarified. Recently, attention has been directed to the relationship of their action to pulmonary surfactants. In the present study, the fatty acid (FA) composition of phosphatidylcholine (PC), which is the main physiological surfactant, was investigated using sputum, respiratory tract fluid, mucin-like substance, lung washings and lung tissue of rabbits. Effects of ambroxol (20 mg/kg, i.s.) on several parameters such as output volume, FA contents of PC, protein content and viscosity of respiratory tract fluid of rabbits were also investigated. In respiratory tract fluid, lung washings and mucin-like substance of rabbits, saturated FA, especially C16:0, were predominant components of PC; while in sputum and lung tissue of rabbits and respiratory tract fluid of hens, unsaturated FA, especially C18:1 and C18:2, were more predominant components in comparison with those in the above specimens. Ambroxol significantly increased the contents of C16:0, saturated FA and total FA of PC, and it also increased protein content with an increase in the viscosity of respiratory tract fluid. These results suggest that in the respiratory tract fluid of rabbits, PCs are pulmonary surfactants, and the increasing secretion of pulmonary surfactant is likely to be involved in the expectorant action of ambroxol.

Ambroxol↗
PubMed1986

A kindred of familial combined hyperlipidemia (FCHL) with proband showing type V hyperlipoproteinemia.

A case of familial hyperlipidemia incidentally found through a 16 year-old high school girl with type V hyperlipoproteinemia and abdominal bouts consistent with this type of hyperlipemia is reported for the first time in Japan. The laboratory findings of the plasma of her father revealed typical hyperlipoproteinemia of type IIa. Nineteen of her 26 kindred were investigated. Type V was seen only in the proband, type IIa in father, paternal grandmother, two paternal aunts, and two paternal cousins, type IV in three paternal cousins. The serum apolipoprotein (apo A-I, A-II, B, C-II, C-III, and E) concentrations were determined by the single radial immunodiffusion technique. The apolipoprotein concentrations were not different from those of normolipidemic control subjects except for apo B, which was higher in the hyperlipidemic members, and apo C-II, C-III, and E, which were higher in the proband.

Adolescent↗