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Biomedical subjects

K Shibata

Publications and source records attributed to K Shibata.

At least 451 records · Page 25Linked to original sources
PubMed1992

Hemichorea associated with ipsilateral chronic subdural hematoma--case report.

Left-sided hemichorea developed suddenly in a 73-year-old male. Computed tomography revealed a left subdural hematoma (SDH) and infarction in the right corona radiata and temporo-occipital region. Hemichorea subsided completely after removal of the SDH. Postoperative single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime revealed a global low-perfusion area in the right cerebral hemisphere. Right carotid angiography demonstrated severe stenosis of the trunk of the right middle cerebral artery. The cerebral blood flow in the right cerebral hemisphere had probably already decreased to nearly the critical level and was reduced further by the left SDH, inducing the left-sided hemichorea due to dysfunction of the right cerebral hemisphere. This case shows that when hemichorea ipsilateral to a SDH is present, it is important to ascertain whether there is a pre-existing ischemic lesion in the contralateral cerebral hemisphere, particularly in the basal ganglia, thalamus, or corona radiata.

Aged↗
PubMed1992

Differences in tyrosine phosphorylated proteins between cells expressing P210bcr/abl and P190bcr/abl.

We analysed differences between the populations of tyrosine phosphorylated proteins in two cell lines, K-562 and MR-87, which express two different bcr-abl fusion gene products, using both immunoprecipitation and Western blotting with an anti-phosphotyrosine antibody. K-562 cells preferentially expressed P210bcr/abl (P210), while MR-87 expressed P190bcr/abl (P190). Tyrosine phosphorylated proteins with a molecular mass of 150 kDa (p150) and 115 kDa (p110) were found in both K-562 and MR-87. A 36 kDa protein (p36) was tyrosine phosphorylated in vivo only in K-562 cells, while proteins with a molecular mass of 140 kDa (p140) and 62 kDa (p62) were found only in MR-87 cells. Moreover, several proteins in the detergent-insoluble cell fraction were differently tyrosine phosphorylated in vitro in K-562 and MR-87 lysates. These results suggest that P210 and P190 may have different substrates, and thus, different signal transduction pathways for cell proliferation, although the differential association of such cellular proteins with the two bcr/abl products remains to be clarified.

Fusion Proteins, bcr-abl↗
PubMed1992

Metabolic fate of nicotinamide in LEC rats.

Metabolic fates of nicotinamide in Wistar and LEC rats were compared. In Wistar rats (normal rats) nicotinamide was generally catabolized to N1-methyl-4-pyridone-3-carboxamide (4-Py) through N1-methylnicotinamide (MNA). But in LEC rats nicotinamide catabolism mainly stopped at MNA. Therefore, the excretion ratio of (N1-methyl-2-pyridone-5-carboxamide + 4-Py)/MNA, which is an index of amino acid adequacy, was much lower in the LEC rats than in the Wistar rats. This phenomenon was attributed to the fact that the 4-Py-forming MNA oxidase activity was much lower in the LEC rats than in the Wistar rats. The NAD contents in liver and blood were also lower in LEC rats than in Wistar rats. These results suggest that the ability to synthesize proteins such as 4-Py-forming MNA oxidase and dehydrogenases may be impaired in LEC rats.

Animals↗
PubMed1992

Alterations in thrombin-induced protein tyrosine phosphorylation of platelets from patients with chronic myelogenous leukemia.

Thrombin is known to stimulate platelet protein tyrosine kinase (PTK). We studied thrombin-induced tyrosine-specific protein phosphorylation in normal platelets and those from patients with chronic myelogenous leukemia (CML) and other myeloproliferative disorders (MPD) using immunoblotting with antiphosphotyrosine (anti-P-Tyr) antibody. In resting platelets, two major phosphotyrosyl (P-Tyr) proteins with molecular masses of 120 kDa (p120) and 60 kDa (p60) were consistently detected both in normal subjects and in CML and other MPD patients. In addition to these P-Tyr proteins, a 36 kDa protein (p36) was predominantly phosphorylated only in CML platelets, using antilipocortin II antibody, we identified this p36 protein as lipocortin. Thrombin enhanced the tyrosine phosphorylation of p120 and p60, not only in normal platelets, but also in CML platelets, although the response was more delayed and the duration was shorter in CML platelets than those in normal platelets. Interestingly, decreased thrombin-induced aggregation was associated with a transient stimulation of p36 phosphorylation in CML platelets. These results suggest that the tyrosine phosphorylation of p36, which was probably identical to lipocortin, inhibits thrombin-induced platelet aggregation through anti-phospholipase A2 (anti-PLA2) activity.

Annexins↗
PubMed1992

Osteogenesis of hydroxyapatite and tricalcium phosphate used as a bone substitute.

Hydroxyapatite (HA) and tricalcium phosphate (TCP) are useful for grafting and augmentation of bone tissue. In this study, conventional and histochemical transmission electron microscopy were used to study osteogenic events at the interface between the implanted materials and adjacent tissue from 1 to 4 weeks postoperatively. The microscopic results indicated that TCP was resorbed more rapidly than HA after implantation, with a notable breakdown of material and replacement by mesenchymal cells with ultrastructural features resembling osteoprogenitor cells and collagen up to 4 weeks postoperatively. Alkaline phosphatase and acid phosphatase reactivity in the tissues helped to identify and differentiate the histologic differences observed between HA and TCP.

Acid Phosphatase↗
PubMed1992

Prothrombin fragment F1 + 2 and thrombin-antithrombin III complex are useful markers of the hypercoagulable state in atrial fibrillation.

It is well known that atrial fibrillation (AF) is one of the most important diseases that predispose patients to thrombosis. We have attempted to identify patients with AF in the hypercoagulable state by measuring molecular markers such as thrombin-antithrombin III complex (TAT) and prothrombin fragment 1 + 2 (PTF) and determining the effect of antithrombotic therapy on these markers; 83 patients with AF were studied. Increased levels of plasma TAT and PTF were more frequently observed in patients with AF and associated mitral stenosis than in patients with AF alone. In cases of AF without mitral stenosis, plasma levels of TAT and PTF were significantly lower in those patients receiving antithrombotic agents (aspirin or warfarin) than in those receiving no antithrombotic agents. Furthermore, plasma levels of PTF were significantly lower in patients given warfarin than in those receiving aspirin. These results suggest that (1) patients with AF and mitral stenosis who are not given warfarin are in an extremely hypercoagulable state and (2) some patients with AF without mitral stenosis who are not given antithrombotic agents are also moderately hypercoagulable. In vivo activation of blood coagulation was more effectively controlled in patients receiving warfarin than in those taking aspirin.

Aged↗
PubMed1992

[A case of endoscopic laser polypectomy for endobronchial hamartoma].

A 70-year-old man was admitted to our hospital because of left-sided chest pain and dyspnea. Chest X-ray film showed a tumor in the left main bronchus and left pleural effusion. On bronchoscopy, a tumor which moved with respiration was observed in the left main bronchus. We successfully performed endoscopic laser polypectomy. Pathological examination revealed non-chondromatous hamartoma.

Aged↗
PubMed1992

[A case report of solitary bone cyst of rib detected from pathological fracture].

A case of solitary bone cyst of rib was reported. The patient was 28-year-old man who was admitted to our hospital complaining of chest pain caused by pathological fracture of the left 10th rib. Chest x-ray film revealed a solitary cystic lesion of the 10th rib. The tumor was removed by extrapleural rib partial resection and the histological examination confirmed the diagnosis of solitary bone cyst.

Adult↗
PubMed1992

[A successful treatment of coronary arteriovenous fistula with Symbas procedure].

A successful treatment of coronary arteriovenous fistula with intraoperative echocardiogram and Symbas procedure is presented. The patient, a 2-year-old male, had been suffering from concealed congestive heart failure from his birth. The cardiac catheterization and angiogram revealed coronary arteriovenous fistula from LAD to right ventricle with large coronary aneurysm. In the operation, no fistula vessels were noted on the cardiac surface. Then, the intraoperative echocardiography was performed, and the fistula pour into right ventricle with aneurysm was found in the myocardium. The fistula was closed with Symbas procedure, and excellent closure could be checked with the intraoperative echocardiogram, too. After this operation, he got well under anticoagulant treatment with "ticlopidine".

Arteriovenous Malformations↗
PubMed1992

[The significance of myelodysplasia in untreated patients with multiple myeloma].

Microscopic analysis of bone marrow smears from ten untreated patients with multiple myeloma (MM) revealed that seven patients had myelodysplastic changes. Of these, five patients had anemia alone while the other two had anemia and leucopenia. The myelodysplastic changes seen in MM were less extensive than those seen in myelodysplastic syndrome (MDS). Moreover, the dysplastic changes in MM were determined to be limited to two or three lineage cells. Dysplastic changes were observed even after clinical signs of MM had improved due to therapy. We consider that the myelodysplastic changes seen in MM can be attributed to MM itself, rather than to the coexistence of MDS and MM. Such findings suggest that the pathogenesis of MM involves a common stem cell which differentiates into multiple lineage cells.

Adult↗
PubMed1991

Presence of human immunoglobulin G anti serum pancreatic elastase 1 autoantibodies and their influence on elastase 1 radioimmunoassay.

Human immunoglobulin G (IgG) anti human pancreatic elastase 1 autoantibodies were detected in sera of patients with pancreatic disorders. The characteristics of these anti elastase 1 autoantibodies and their influence on radioimmunoassay (RIA) for elastase 1 were investigated. They were placed in the IgG class by the double antibody method, and most were assumed to be of a monoclonal type from their elution profiles in gel filtration analysis. The presence of autoantibodies in serum caused an increase in apparent elastase 1 values and a decrease in the recovery of elastase 1 exogenously added to the serum. These results suggest that elastase 1 immunoassay data for autoantibody positive sera can cause misjudgement of clinical stages of patients.

Autoantibodies↗
PubMed1991

High-performance liquid chromatographic determination of 3-hydroxykynurenine with fluorimetric detection; comparison of preovulatory phase and postovulatory phase urinary excretion.

A high-performance liquid chromatographic assay for 3-hydroxykynurenine in human urine is described. A fluorescent derivative of 3-hydroxykynurenine was prepared, based on the reaction of the compound with p-toluenesulphonyl chloride in a basic medium. The analytical method for the measurement of the fluorescent compound employed a Tosoh ODS 80 column eluted with 10 mM potassium dihydrogenphosphate (pH 4.5) and acetonitrile (3:2, v/v) and detection at an excitation wavelength of 375 nm (10 nm bandpass) and an emission wavelength of 455 nm (10 nm bandpass). The column temperature was maintained at 25 degrees C. The detection limit was 3 pmol (673 pg) at a signal-to-noise ratio of 5:1. The fluorescent derivative of 3-hydroxykynurenine was eluted at ca. 12.5 min. The technique was applied to the analysis of human urine. The total analysis time was ca. 15 min.

Adult↗
PubMed1991

Structural organization of the pigment cell-specific gene located at the brown locus in mouse. Its promoter activity and alternatively spliced transcript.

The pigment cell-specific gene, located at the brown (b) locus in mouse, has been cloned and characterized. Its gene product is required for the formation of black melanin rather than brown, although its exact function remains to be elucidated. We thus tentatively named it b-locus protein in this report. The b-locus protein gene is about 18 kilobase pairs long and organized into 8 exons and 7 introns. Functional analysis of its promoter region suggests that the nucleotide residues -38/154 is sufficient to direct the pigment cell-specific transcription in melanoma whole cell extracts. On the other hand, we were unable to detect its transcripts in HeLa whole cell extracts. Sequence comparison with the promoter region of the tyrosinase gene, another pigment cell-specific gene, reveals that two elements of the b-locus protein gene (-33/-24 and 18/28) are also conserved in the tyrosinase gene at equivalent positions, suggesting that these two elements may be involved in their pigment cell-specific transcription. Furthermore, we have cloned a cDNA, pMT3, coding for an isoform of b-locus protein from a cDNA library of mouse B16 melanoma cells. Sequence analysis of pMT3 reveals a deletion of 103 base pairs, which corresponds to the 5'-end of the exon 8 of the b-locus protein gene, indicating that pMT3 represents a mRNA species generated by alternative splicing. Since this deletion changes the reading frame and eliminates the transmembrane domain of b-locus protein, the pMT3-type mRNA may code for a soluble isoform. Such an isoform, consisting of 553 amino acids, differs only in its carboxyl terminus and is larger than b-locus protein by 16 amino acids. Using transient expression assays, we confirmed that such an isoform is able to react with anti-b-locus protein monoclonal antibody, TMH-1, suggesting that a b-locus protein isoform may have some function in pigmentation.

Amino Acid Sequence↗