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Biomedical subjects

K Miyahara

Publications and source records attributed to K Miyahara.

At least 73 records · Page 4Linked to original sources
PubMed1998

Components of the ether-insoluble resin glycoside-like fraction from Cuscuta chinensis.

A trisaccharide and four new glycosidic acids, named cuscutic acids A-D, along with known organic acids, acetic acid, propionic acid, (2S)-2-methylbutyric acid, tiglic acid, (2R, 3 R)-nilic acid, (11S) convolvulinolic acid and (11S)-jalapinolic acid have been isolated from the alkaline hydrolysate of the ether-insoluble resin glycoside-like fraction of the seeds of Cuscuta chinensis. The compounds were characterized on the basis of chemical and physical data.

Carbohydrate Conformation↗
PubMed1998

Functional interaction of Isr1, a predicted protein kinase, with the Pkc1 pathway in Saccharomyces cerevisiae.

Staurosporine is a potent inhibitor of protein kinase C. To identify the genes that functionally interact with the Pkc1 pathway of the yeast Saccharomyces cerevisiae, we screened for the genes that cause induced staurosporine sensitivity when overexpressed from a galactose-inducible promoter. The novel gene ISR1 encodes a predicted protein kinase with the highest sequence similarity to mammalian Raf in the kinase domain. Drug sensitivity induced by ISR1 overexpression is specific to staurosporine. Although ISR1 disruption causes no obvious phenotype, it does exacerbate the phenotypes of a temperature-sensitive allele (stt1-1) of PKC1, but not of the mpk1 and bck1 mutants of the Mpk1 MAP kinase pathway. These results suggest that Isr1 functions in an event important for growth in a manner redundant with a Mpk1-independent branch of the Pkc1 signalling pathways.

Culture Media↗
PubMed1998

Differentiation between chondroma and squamous cell carcinoma: evaluation of subtraction image of MRI.

The image processing procedure has become widely applied as a visual aid in imaging diagnosis. The subtraction image of MRI obtained by digitally subtracting an unenhanced image from a contrast-enhanced image, depicted a discrete distribution of the contrast agent. Subtraction images in the clinical cases were compared. The subtraction image in a case of chondroma demonstrated a relatively uniform distribution of a contrast agent, with a well delineated neoplastic lesion. The subtraction image in a case of squamous cell carcinoma, the contrast agent was distributed heterogeneously in the carcinoma and well permeated into the muscle. Different patterns of subtraction image were obtained in the clinical cases of chondroma and squamous cell carcinoma in this study. The findings suggest the potential usefulness of the subtraction image for diagnosing the degree of malignancy.

Animals↗
PubMed1998

The contrecoup injury in a cat case of traffic accident: MRI findings.

The clinical application of MRI of a cat case of traffic accident was examined. On admission, the animal was unconscious and remained so for 2 days. Radiographs disclosed a fracture in the parietal bone. From the temporary unconscious status and the fracture, cerebral damage was suspected and an MRI examination was performed. The contrecoup injury in the cat case of traffic accident which could not be diagnosed by radiography was diagnosed by MRI examination.

Accidents, Traffic↗
PubMed1998

Isolated levocardia associated with absence of inferior vena cava, lobulated spleen and sick sinus syndrome. A case report.

We evaluated a 68-year-old male patient with isolated levocardia without intracardiac anomaly. The patient's condition was complicated by the absence of the inferior vena cava, a lobulated spleen and sick sinus syndrome. Isolated levocardia without intracardiac anomaly is very rare and only 25 cases of this disease have been reported, to our knowledge. In general, it is accepted that cardiac rhythm disorder is frequently observed in cases of isolated levocardia and/or absence of inferior vena cava. However, there are few cases of isolated levocardia without intracardiac anomaly complicated by the absence of the inferior vena cava, a lobulated spleen and apparent sick sinus syndrome.

Aged↗
PubMed1998

[A case of primary squamous cell lung cancer invading the wall of the distal aortic arch and the left subclavian artery: successful surgical management using ECC with selective cerebral perfusion].

A 37-year-old male was referred to our hospital with symptoms suggesting pneumonia. The preoperative diagnosis was primary lung cancer of the left upper lobe invading the distal aortic arch (DAA) (T4, stage IIIB). Complete resection was performed with associated resection of the pneumonectomy, DAA, and left subclavian artery. Dacron graft replacement was performed using ECC with selective cerebral perfusion. Histological examination revealed squamous cell carcinoma, n1 and negative surgical margins. We expect this patient to achieve long-term survival. We conclude that ECC with selective cerebral perfusion is both safe and effective for pulmonary surgery in cases with combined resection of the DAA.

Adult↗
PubMed1997

Mutational analysis of Yap1 protein, an AP-1-like transcriptional activator of Saccharomyces cerevisiae.

To define the essential amino acid residues of Yap1 in stress response, we generated yap1 mutations by in vitro mutagenesis, which cause defects in mediating resistance to the stress of H2O2, but not of CdCl2. Sequence analysis of the mutant yap1 genes revealed three point mutations and two truncation mutations near the carboxy-terminus. The truncation mutations resulted in hyperresistance to cadmium. Northern blot analysis of stress-induced levels of TRX2 and GSH1 mRNAs indicated that the ability of the mutant Yap1 protein to induce transcriptional activation of target genes correlates well with its ability to confer stress resistance. The carboxy-terminal domain of Yap1 appears to act negatively in cadmium resistance.

Aminoacyltransferases↗
PubMed1997

CMO I deficiency caused by a point mutation in exon 8 of the human CYP11B2 gene encoding steroid 18-hydroxylase (P450C18).

Corticosterone methyloxidase I (CMO I) deficiency is an autosomal recessive disorder of aldosterone biosynthesis. To determine further the molecular genetic basis of CMO I deficiency, a patient of Turkish origin that suffered from CMO I deficiency was studied. Nucleotide sequencing of the PCR-amplified exons from the genomic DNA of this patient revealed a single point mutation CTG (leucine) CCG (proline) at codon 461 in exon 8 of CYP11B2, which is involved in the putative heme binding site of steroid 18-hydroxylase (P450(C18)). The expression study using a cDNA introducing the point mutation revealed that the amino acid substitution totally abolishes the P450(C18)p3 enzyme activities required for conversion of 11-deoxycorticosterone to aldosterone, even though the mutant product was detected in the mitochondrial fraction of the transfected cells. These results suggest that this point mutation causes CMO I deficiency.

Aldosterone↗
PubMed1997

Atrial fibrillation activates platelets and coagulation in a time-dependent manner: a study in patients with paroxysmal atrial fibrillation.

OBJECTIVES: To determine whether atrial fibrillation (AF) alone affects the fibrinocoagulation system, we examined the relation between fibrinocoagulation activity and duration of AF in patients with paroxysmal AF (PAF). BACKGROUND: Patients with chronic AF are at higher risk for stroke and a hypercoagulative state. It is not clear whether this hypercoagulative state is attributable to AF alone or to the underlying disease. There are no reports on the fibrinocoagulation properties in PAF. METHODS: Fibrinocoagulation variables in 21 patients with PAF were measured during AF and 7 days after recovery of sinus rhythm. There were positive correlations between the duration of AF and beta-thromboglobulin, platelet factor 4, thrombin-antithrombin III complex and fibrinogen. These variables increased significantly 12 h after the occurrence of PAF; thus, patients were classified into two groups according to the duration of PAF: PAF-I group (< 12 h, n = 10), PAF-II group (> or = 12 h, n = 11). Nine age-matched, healthy subjects formed the control group. RESULTS: Levels of beta-thromboglobulin and platelet factor 4 were significantly higher (p < 0.001) by two-way repeated measures analysis of variance (ANOVA), and thrombin-antithrombin III complex and fibrinogen levels tended to be but were not significantly higher (p = 0.06, ANOVA), in the PAF-II group than in the PAF-I group. There were no significant differences between groups in activated partial thromboplastin time, D-dimer or plasmin inhibitor complex. CONCLUSIONS: These results indicate that AF itself enhances platelet aggregation and coagulation, which are influenced by the duration of AF. The acceleration of platelet activity and coagulability occurred 12 h after the occurrence of AF.

Analysis of Variance↗
PubMed1997

Blood cardioplegia infusion using a recirculation type circuit generates bradykinin in significant amounts during open heart surgery.

The single pass type (SP) of blood cardioplegia is commonly used in North America during open heart surgery. However the recirculation type (RC) of blood cardioplegia is still widely used in other areas including Japan. Infusion blood cardioplegia using the latter technique often decreases the perfusion pressure. To determine the cause for this, blood levels of bradykinin (BK) were measured in cardiopulmonary bypass (CPB) and the 2 types of blood cardioplegic circuits. As the BK levels in the RC cardioplegia (>3,000 pg/ml) rose, the perfusion pressure decreased abruptly with the increase of the BK levels in the CPB circuit. With SP cardioplegia, the BK level was not increased either during cardioplegia (p < 0.009) or CPB (p < 0.009), and the perfusion pressure was not decreased (p < 0.02). We concluded that the SP circuit is superior to the RC one because of the lesser production of BK and thus lesser fluctuation of perfusion pressure.

Aged↗
PubMed1997

Fruiting-inducing activity and antifungal properties of lipid components in members of Annelida.

Fruiting-inducing activity and antifungal properties of lipid components in the phylum Annelida were examined. Some amphoteric cerebrosides carrying a phosphocholine group showed fruiting-inducing activity on Schizophyllum commune, and one of them possessed activity comparable to that of Sch II, the most potent substance known. Furthermore, alkyl lysophosphatidylcholines were found to have an inhibitory effect on the growth of phytopathogenic fungi, Alternaria kikuchiana and Phomopsis mali. The relationship between structure and biological activities is discussed.

Alternaria↗
PubMed1997

Resin glycosides. XXV. Multifidins I and II, new jalapins, from the seed of Quamoclit x multifida.

Alkaline hydrolysis of the ether-soluble resin glycoside fraction of seeds of Quamoclit (Q.) x multifida, a hybrid between Q. pinnata and Q. coccinea, gave new glycosidic acids, multifidinic acids A and B, along with two known glycosidic acids, quamoclinic acid A and operculinic acid A, and three organic acids, (2S)-2-methylbutyric acid, n-decanoic acid and n-dodecanoic acid. Further, as major ether-soluble resin glycosides, new jalapins named multifidins I and II, were isolated accompanied by quamoclins I-IV, which were previously obtained from seeds of Q. pinnata. The structures of multifidins I and II, and multifidinic acids A and B have been determined on the basis of chemical and spectral data.

Butyrates↗
PubMed1997

Computed tomography and magnetic resonance findings in two dogs and a cat with intracranial lesions.

Two dogs and a cat with intracranial lesions were evaluated by both computed tomography (CT) and magnetic resonance (MR) imaging. In a dog with vestibular syndrome, better quality images of the medulla oblongata surrounded by thick bones were obtained by MR than by CT, on which the appearance of artifacts impeded the clear image of the area. In a dog with multiple brain metastases of lymphoma, contrast CT delineated lesions more clearly than MR, which was performed one week after CT. During that week dexamethasone which might affect the clarity of MR images of the lesion was administered to reduce brain edema. In a cat with meningeal syndrome of lymphocytic leukemia, only contrast MR imaging identified the width and site of the lesion. These results indicate that it is necessary to select either one of these imaging methods according to the type and site of lesions that are suspected in a particular case.

Animals↗
PubMed1997

[Successful emergency coronary artery bypass grafting in a patient with systemic lupus erythematosus under hemodialysis therapy].

A 38-year-old woman, who had been suffering from systemic lupus erythematosus (SLE) and receiving steroid therapy for the past 25 years, underwent a successful emergency coronary artery bypass grafting for unstable angina. She had also been treated with a 10-year period of hemodialysis therapy for chronic renal failure. Her coronary angiography revealed the heavily calcified ectatic right coronary artery with a thrombus formation in its proximal portion associated with severe stenosis in the proximal left coronary artery. The left internal thoracic artery was anastomosed to #7 and the saphenous vein to #3, respectively. Postoperative coronary angiography performed one month later revealed both grafts to be patent with no stenosis. Ischemic heart disease (IHD) is one of the major complication limiting the prognosis of the patient with SLE. We discuss the point related to cause of IHD and the surgical management.

Adult↗
PubMed1997

Pitfalls of intervention therapy in a patient with anomalous origin of the right coronary artery from the left sinus of Valsalva associated with organic stenosis.

A 64-year-old man visited our hospital with a complaint of exertional chest discomfort. Exercise electrocardiography revealed ST segment depression in the V4-V6 leads, and exercise thallium myocardial scintigraphy demonstrated myocardial ischemia in the area of the right coronary artery, suggesting effort angina. Diagnostic coronary angiography revealed an anomalous origin of the right coronary artery from the left sinus of Valsalva and 90% organic stenosis at the proximal portion. We performed percutaneous transluminal coronary angioplasty (PTCA), but repeat PTCA was required 3 months later because of restenosis. Follow-up angiography 1 year later showed regression of the stenotic lesion to less than 50% diameter compared with the data obtained 3 months after the second PTCA. However, exercise 99mtechnetium-tetrofosmin myocardial scintigraphy disclosed obvious myocardial ischemia in the inferior region. These results suggested that the myocardial ischemia in this particular patient was caused not only by the organic stenosis but also by the anatomic anomaly which might reduce coronary blood flow during exercise. Such patients should be followed up cautiously with much more sophisticated methodology.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Long-term late results of pericardiectomy for constrictive pericarditis].

Twenty-four cases of the constrictive pericarditis were operated on pericardiectomy from 1966 to 1990. One case died because of massive bleeding, LOS, and respiratory failure immediately after the operation. A long-term follow up study was performed up to 27 years (mean 13.1 years) in other cases. Ten cases died during the follow up period (cardiac: 6, non cardiac: 4). Five cases of the cardiac deaths had major complications: tabes dorsalis, chronic respiratory failure, pacemaker implantation, mitral regurgitation, emergency operation at high age (78 years old). The survival rates of 5, 10, and 15 years were 85%, 67%, and 58.2%, respectively (Kaplan-Meier). All of survival cases are now in NYHA I or II class in satisfactory. We concluded that pericardiectomy is a very effective treatment for constrictive pericarditis but a more careful follow up is required especially in cases complicated with other major problems because cardiac function is not so recovered as normal level after surgery due probably to readhesion and fibrotic changes of the myocardium.

Adult↗
PubMed1996

The involvement of the Saccharomyces cerevisiae multidrug resistance transporters Pdr5p and Snq2p in cation resistance.

The ATP-binding cassette superfamily proteins Pdr5p and Snq2p of Saccharomyces cerevisiae are implicated in multidrug resistance. Here, we show that these transporters are also involved in cation resistance. Null mutants of PDR5 and SNQ2 genes exhibit increased sensitivity to NaCl, LiCl and MnCl2. The mutant cells grown in the presence of high concentrations of these metal salts contain higher levels of the metals than wild-type cells. The expression of PDR5 and SNQ2 is induced by the metal salts. These results provide evidence that the yeast drug transporters contribute to cation resistance by regulating cellular cation homeostasis under ionic stress conditions.

ATP-Binding Cassette Transporters↗