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Biomedical subjects

Y Kawamura

Publications and source records attributed to Y Kawamura.

At least 19 recordsLinked to original sources
PubMed1992

Complete amino acid sequence of subunit e of rat liver mitochondrial H(+)-ATP synthase.

Subunit e of H(+)-ATP synthase from rat liver mitochondria was isolated from the purified enzyme by reverse-phase high-performance liquid chromatography. The amino acid sequence of the subunit was determined by automated Edman degradation of the whole protein and derived peptides. The nucleotide sequence of the import precursor of subunit e of rat liver H(+)-ATP synthase was determined from a recombinant cDNA clone isolated by screening a rat hepatoma cell line H4TG cDNA library with a probe DNA. The sequence was composed of 289 nucleotides including a coding region for the import precursor of subunit e and noncoding regions on the 5'- and 3'-sides. The possible import precursor of subunit e and its mature polypeptide deduced from the open reading frame consisted of 71 and 70 amino acid residues with molecular weights of 8254 and 8123, respectively. Subunit e is a basic hydrophilic protein with an isoelectric point of 9.78. The sequence of the rat subunit e is highly homologous with that of subunit e of bovine heart, but has no homology with any subunit of bacterial or chloroplast H(+)-ATP synthase. The function of subunit e is unknown. However, a homology search in the database of the National Biomedical Research Foundation revealed that residues 34-65 of subunit e are homologous with residues 90-117 of troponin T, and with residues 529-561 of h-caldesmon and residues 289-319 of l-caldesmon, which are the homologous sequences corresponding to the Ca(2+)-dependent tropomyosin-binding region of troponin T.

Amino Acid Sequence↗
PubMed1992

A simple, rapid method for purification of epsilon-subunit, coupling factor 6, subunit d, and subunit e from rat liver H(+)-ATP synthase and determination of the complete amino acid sequence of epsilon-subunit.

The rat liver mitochondrial epsilon-subunit, coupling factor 6, subunit d, and subunit e of H(+)-ATP synthase, which are all extra subunits with no counterparts in Escherichia coli, were purified by reverse-phase high performance liquid chromatography. The complete amino acid sequence of the rat epsilon-subunit was determined by automated Edman degradation of the whole protein and derived peptides. The protein contains 50 amino acids and has a molecular mass of 5635 kDa. It is a basic hydrophilic protein with an isoelectric point of 10.5. The sequence of the rat epsilon-subunit is highly homologous with that of the epsilon-subunit of bovine heart and slightly similar to those of the epsilon-subunit of the yeast and sweet potato mitochondria. However, it has no homology with any subunit of bacterial or chloroplast H(+)-ATP synthase.

Amino Acid Sequence↗
PubMed1992

cDNA cloning of rat proteasome subunit RC1, a homologue of RING10 located in the human MHC class II region.

The nucleotide sequence of a cDNA that encodes a new subunit, named RCl, of rat proteasomes (multicatalytic proteinase complexes) has been determined. The polypeptide predicted from the open reading frame consisted of 208 amino acid residues with a calculated molecular mass of 23, 130, which is consistent with the size obtained by electrophoretic analysis of purified RCl. The partial amino acid sequences of several fragments of RCl, obtained by protein chemical analyses, were found to be in excellent accordance with those deduced from the cDNA sequence. Surprisingly, the overall structure of RCl was found to be almost identical to that of recently isolated RING10, whose gene is located in the class II region of the human MHC gene cluster. This finding suggests that RCl is a homologue of human RING10, supporting the proposal that proteasomes are involved in the antigen processing pathway.

Amino Acid Sequence↗
PubMed1992

cDNA sequence and expression of a phosphoenolpyruvate carboxylase gene from soybean.

A full-length cDNA encoding a subunit of phosphoenolpyruvate carboxylase (PEPC) was isolated from a developing seed expression library of the C3 plant Glycine max. The corresponding mRNA is present at similar levels in leaf, stem, root and developing seed. Two potential start codons exist, and the activity of protein initiated from the first such codon could be subject to regulation by protein kinase. Sequence comparison shows a similar upstream start codon in the case of the Ppc2 gene from Mesembryanthemum crystallinum, previously assumed to lack the sequences necessary for phosphorylation. The soybean encoded protein tends to resemble other 'C3-type' PEPC proteins more closely than those implicated in C4 or crassulacean acid metabolism.

Amino Acid Sequence↗
PubMed1992

Hemoglobin Kansas found in a patient with polycythemia.

A 62-year-old woman, long suspected of having heart disease, was admitted to our hospital for thorough examination. Her hemoglobin level was 17.7 g/dl and her 2.3-DPG level was 8.90 microM/ml RBC. The patient proved to have polycythemia, hemoglobin Kansas, and diabetes mellitus. To our knowledge, this is the third case of hemoglobin Kansas in the world.

2,3-Diphosphoglycerate↗
PubMed1992

Chicken leg muscle alpha-connectin as studied by a monoclonal antibody to the 1200 kDa fragment.

Chicken leg gracilis muscle contained only alpha-connectin (ca 3000 kDa) without beta-connectin. When myofibrils were kept standing for 20 hr at 4 degrees C, alpha-connectin was degraded to beta-connectin (ca 2000 kDa) and 1200 kDa peptide. The latter was prepared from myofibrils and purified by gel filtration in the presence of SDS. A monoclonal antibody, alpha 7, to this 1200 kDa fragment was prepared. The antibody reacted with the 1200 kDa fragment and its mother molecule alpha-connectin, but not with beta-connectin. Immunoelectron microscopy using alpha 7, as well as other antibodies to chicken breast muscle beta-connectin, revealed that the 1200 kDa peptide covered the portion of alpha-connectin from the Z line to the N2 line region in the I band of chicken leg gracilis muscle sarcomeres. The results were in good agreement with those observed in rabbit skeletal muscle.

Animals↗
PubMed1992

Changes in plasma levels of thrombomodulin during haemodialysis.

We studied the changes in plasma levels of thrombomodulin (TM) known to be present on vascular endothelial cells and released into circulating blood following damage to endothelial cells, during haemodialysis in 49 patients with end-stage chronic glomerulonephritis maintained on haemodialysis. After a single haemodialysis, plasma levels of TM were significantly elevated from 38.4 +/- 13.8 ng/ml to 46.8 +/- 14.6 ng/ml (p less than 0.05). Plasma levels of TM before haemodialysis were significantly higher in the cases of long-term haemodialysis than in those of short-term haemodialysis (p less than 0.01). From these observations, increased plasma levels of TM may be due to decreased clearance of TM by renal insufficiency, or damage to endothelial cells induced by the recurrent haemodialysis. In those patients with a greater residual blood volume in a dialyser, the changes in plasma levels of thrombin-antithrombin III complex and TM during a single haemodialysis were significantly higher. From these findings, it was suggested that endothelial cell damage is more severe in patients with greater residual blood volume.

Adult↗
PubMed1992

Mannan-coated liposome delivery of gadolinium-diethylenetriaminepentaacetic acid, a contrast agent for use in magnetic resonance imaging.

Gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), a paramagnetic contrast agent for use in magnetic resonance imaging (MRI) was bound to stearylamine and incorporated into the liposomal membranes (Gd-DTPA liposomes). In addition, the Gd-DTPA liposomes were coated with mannan (cholesterol-aminoethylcarbamylmethyl mannan), a polysaccharide, to obtain the mannan-coated liposomes. An in vitro MRI study showed that the Gd-DTPA liposomes produced a greater intensity of contrast than did the Gd-DTPA solution with a reduced T1 relaxation time. Intravenous injection of the Gd-DTPA liposomes containing 153Gd or liposomes containing 153Gd or 14C-DTPA to mice showed an accumulation of Gd-DTPA primarily in the liver and lung. When the mannan-coated liposomes were administered, an increased uptake of Gd-DTPA by these tissues was demonstrated. The mannan-coated liposomes may enhance contrast of the liver in MRI at a lower dose of Gd-DTPA.

Animals↗
PubMed1992

The effect of intermittent coronary sinus occlusion on coronary sinus pressure dynamics and coronary arterial flow.

The effect of intermittent coronary sinus occlusion (ICSO) with a balloon-tipped catheter on coronary arterial flow and coronary sinus pressure (CSP) dynamics were studied in open-chest dogs. During coronary sinus occlusion (CSO), CSP gradually rose and finally reached a plateau, while left coronary arterial mean flow velocities decreased. After the release of CSO, CSP immediately returned to baseline values, and the flow velocities correspondingly increased over the baseline values (hyperemic response). The decrease in ratios of flow velocities during CSO were unrelated to the duration of CSO, whereas hyperemic responses were positively correlated with the CSO duration. In the repetitive application of CSO (ICSO), inadequately short duration of release period decreased the net volume of coronary arterial flow significantly. Moreover, hyperemic responses were abolished by maximal coronary vasodilation with intravenous adenosine, augmented by combination with coronary sinus retroperfusion and reduced by coronary arterial ischemia. These findings indicate the presence of a compensatory regulating mechanism in the coronary circulation during ICSO. We should attach much importance to this mechanism for the effectiveness of ICSO. To be accurate, the changes in coronary arterial flow as well as CSP dynamics should be considered when choosing adequate occlusion-release intervals of ICSO.

Adenosine↗
PubMed1992

Site of hypoxic pulmonary vasoconstriction in pulsatile perfused canine lung lobes.

To elucidate the site of hypoxic pulmonary vasoconstriction (HPV) in the dynamic lung, we studied the effect of alveolar hypoxia (0 approximately 4% O2) on excised canine lung lobes with pulsatile perfusion from artery to vein (antegrade perfusion: AP) or vein to artery (retrograde perfusion: RP), and compared responses to hypoxia with those to serotonin and histamine. In our preparation, increases in the pulmonary vascular resistance (R) resulted in a wide range of decreases in the flow wave amplitude at the lobar inflow site (FA). These decreases in FA reflected reductions in the compliance of the vasculature proximal to the main site of resistance. The FA/R ratios of serotonin were 2.29 in AP and 0.24 in RP indicating the predominant arterial constriction, those of histamine were 0.07 in AP and 1.24 in RP indicating the selective venous constriction. In contrast, the responses to hypoxia were 0.38 in AP and 0.42 in RP. These results suggest that HPV occurs not only on the arterial side but on the venous side in the dynamic lung, and the main site of HPV is located in the peripheral pulmonary vasculature, between muscular arteries and veins which are constricted by serotonin and histamine.

Animals↗
PubMed1992

Multiple liver abscesses secondary to Yersinia enterocolitica.

A 37-year-old male, a poorly-controlled insulin-dependent diabetic patient, was admitted to our hospital with complaints of high fever and confusion. Laboratory data showed hyperglycemia, positive inflammatory reaction and liver dysfunction. Blood culture demonstrated Yersinia enterocolitica. Liver CT scan showed multiple low density areas. These data were consistent with a diagnosis of liver abscess secondary to Yersinia enterocolitica. He died of disseminated intravascular coagulation; subsequent autopsy confirmed the clinical diagnosis. Liver abscess secondary to Yersinia enterocolitica with septicemia is rare, but has been reported in compromised hosts. In the mechanism of this disease, the alimentary tract has been suggested to be the port of entry in most cases.

Adult↗
PubMed1992

Cinatrins, a novel family of phospholipase A2 inhibitors. I. Taxonomy and fermentation of the producing culture; isolation and structures of cinatrins.

Cinatrins A, B, C1, C2 and C3, a family of phospholipase A2 inhibitors were isolated from the fermentation broth of Circinotrichum falcatisporum RF-641. They were found to be novel spiro-gamma-dilactones and gamma-lactones derived from 1,2,3,5-tetra or 1,2,3(or 1,2,4)-trihydroxypentadecane-1,2,3-tricarboxylic acids. Structures were elucidated by MS and NMR studies and chemical transformations. The structure of cinatrin C3 was confirmed by X-ray crystallographic analysis, and its absolute configuration was determined by comparison of the CD spectra with related compounds.

Chromatography↗
PubMed1992

Depudecin: a novel compound inducing the flat phenotype of NIH3T3 cells doubly transformed by ras- and src-oncogene, produced by Alternaria brassicicola.

A novel compound depudecin inducing the flat phenotype of ras- and src- transformed NIH3T3 cells at a concentration of 1 microgram/ml was isolated from the culture broth of Alternaria brassicicola. Based on its spectroscopic characteristics and X-ray crystallographic analysis of its bis-(1S)-(-)-camphanate, the structure of depudecin was determined to be (2R,3S,4S,5E,7S,8S,9R)-2,9- dihydroxy-3,4;7,8-diepoxy-undeca-5,10-diene.

3T3 Cells↗
PubMed1992

[A case of adult onset phosphoglucomutase deficiency].

A case of 38-year-old male with adult onset phosphoglucomutase (PGM) deficiency was reported. The patient was admitted at Kawamura Hospital (Gifu City) for evaluation of easy fatiguability and exercise-induced weakness of the extremities since he was 20 years old. Physical examination revealed moderate muscle weakness, wasting of extremities, bilateral clubbed fingers and hypoesthesia of distal portion of extremities. Fasting plasma glucose was low (58 mg/dl). Venous concentration of lactate failed to rise after an ischemic forearm exercise test. An epinephrine tolerance test revealed hyperglycemic response. Studies of anaerobic glycolysis in vitro using muscle homogenates with the substrate between glucose-1-phosphate and glucose-6-phosphate showed decreased lactate production. Direct assay of individual muscle glycolytic enzymes demonstrated reduction of PGM activity (15% of normal, n = 12). Biopsy study with PAS staining of quadriceps femoris muscle demonstrated small amount of deeply staining glycogen in subsarcolemmal area. Electron microscopic examination revealed muscle destruction with small amount of glycogen in subsarcolemmal and intermyofibrillar spaces. Sural nerve biopsy showed degeneration of myelinated and unmyelinated fibers but there was no apparent accumulation of glycogen. From the clinical, biochemical and histopathological evidences, the patient might be a rare case of adult onset PGM deficiency.

Adult↗
PubMed1992

Temporomandibular joint movement. Evaluation of protrusive splint therapy with GRASS MR imaging.

Ten temporomandibular joints (TMJs) of 5 healthy volunteers and 19 TMJs of internal derangements in 16 patients with splint therapy were examined with MR imaging. T1-weighted images were obtained only in the closed mouth position, and gradient recalled acquisition in steady state (GRASS) images were obtained in active opening and closing phases, allowing a pseudodynamic display of TMJ movement. All patients received protrusive splint treatment. The usefulness of MR imaging to assess the efficacy of splint therapy was evaluated. Corrected disk position with the splint in place was clearly demonstrated in 9 TMJs, corresponding with elimination of reciprocal clicking. Ten other TMJs of anterior disk displacement without reduction showed uncorrected disk position by the splint. This information could confirm the therapeutic efficacy, or suggest other treatment alternatives. GRASS MR imaging can provide accurate and physiologic information about disk function in initial and follow-up assessment of protrusive splint therapy.

Adolescent↗