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Biomedical subjects

Y Goto

Publications and source records attributed to Y Goto.

At least 19 recordsLinked to original sources
PubMed1992

Segmental cytochrome c-oxidase deficiency in CPEO: teased muscle fiber analysis.

In an attempt to elucidate the pathogenesis of focal cytochrome c-oxidase (COX) deficiency in skeletal muscle from patients with chronic progressive external ophthalmoplegia (CPEO), we examined the longitudinal distribution of COX activity in single muscle fibers from 6 CPEO patients with muscle mitochondrial DNA (mtDNA) deletions. A new method for teasing single muscle fibers, recently developed in our laboratory, revealed fibers with COX-positive and -negative segments in all 6 patients. The borders between the enzyme-positive and -negative segments in these fibers were sharply delineated, so that the length of each COX-negative segments could be accurately measured. The proportion of the sum of the lengths of the enzyme-negative segments to the total length of the muscle fibers correlated well with the proportion of deleted mtDNA, suggesting that abnormal mitochondria harboring mutant mtDNA may be responsible for the focal loss of COX activity.

Adolescent↗
PubMed1992

Cardiac muscle fiber force versus length determined by a cardiac muscle crossbridge model.

A mathematical model incorporating Huxley's sliding filament crossbridge muscle model coupled with parallel and series elastic components was simulated to examine force-length relations under different external calcium concentrations. Several researchers have determined experimentally in both papillary muscle preparations and in situ heart experiments that the calcium concentration (or effective concentration from inotropic agents) will affect the strength and convexity of the cardiac muscle fiber force-length relations. Simulations were performed over a several-order-of-magnitude range of calcium concentrations in isometric contractions and these showed that the force-length curve convexity was changed. Simulation results demonstrated that increasing the stiffness in the model contractile element or series elasticity element did not change the force-length convexity. Increasing the series elasticity element stiffness did slightly change the shape of the force-length curve. The model predicts that the curve convexity changes as a result of the calcium-troponin interactions.

Calcium↗
PubMed1992

Similar oxygen cost of myocardial contractility between DPI 201-106 and epinephrine despite different subcellular mechanisms of action in dog hearts.

The effects of DPI 201-106 (a novel, cyclic AMP-independent positive inotropic agent with Ca(2+)-sensitizing and Na(+)-channel agonistic mechanisms) on myocardial mechanics and energetics were assessed in the excised cross-circulated dog left ventricle. In the first protocol, the relation between left ventricular oxygen consumption (VO2) and systolic pressure-volume area (PVA) was analyzed before and during administration of DPI 201-106. The reciprocal of the slope of the VO2-PVA relation has been shown to reflect the contractile efficiency, and the VO2-intercept consists of the oxygen cost of contractility-dependent excitation-contraction coupling and basal metabolism. DPI 201-106 increased Emax (contractility index) and elevated the VO2-PVA relation in a parallel manner, i.e., the VO2-intercept increased without a change in the slope. In the second protocol, the increase in the VO2-intercept of the VO2-PVA relation for a unit increase in Emax (i.e., oxygen cost of enhanced contractility) was compared between DPI 201-106 and epinephrine in a paired manner in each heart. Epinephrine significantly abbreviated the time to end systole, whereas DPI 201-106 did not, suggesting that the mechanism of inotropic action differed between the two drugs. However, the oxygen cost of enhanced contractility was the same between the two drugs in each heart. Therefore, DPI 201-106 did not alter the contractile efficiency nor spare the oxygen cost of enhanced contractility as compared to epinephrine under the present experimental conditions. This suggests that the Ca(2+)-sensitizing effect of DPI 201-106, if any, is too small to spare the oxygen cost of contractility in the blood-perfused, non-failing dog heart.

Animals↗
PubMed1992

A symptomatic female patient with Duchenne muscular dystrophy diagnosed by dystrophin-staining: a case report.

We report a case of symptomatic carrier of Duchenne muscular dystrophy (DMD) in a 14-year-old girl with no prior family history of DMD. She presented with chest pain, enlarged calf muscles, an elevated serum creatine kinase (CK), and decreased left ventricular function. Histological examination of skeletal muscle revealed myopathic changes and immunostaining with anti-dystrophin antiserum demonstrated a mosaic pattern which are compatible with the observations in carriers of DMD. Southern blots using the dystrophin cDNA revealed no evidence of a deletion within the DMD gene in the patient or in her mother. We found this observation interesting for two reasons: 1. Cardiomyopathy is rare in female DMD patients. 2. Immunostaining of a muscle biopsy with anti-dystrophin serum proved to be valuable in the diagnosed for symptomatic carriers of the dystrophin gene mutation.

Adolescent↗
PubMed1992

Human sera from varicella-zoster virus (VZV) infections cross-react with human T cell leukaemia virus type 1 (HTLV-1): common epitopes in VZV gene 22 protein and HTLV-1 p19 gag protein.

Twenty-nine of 100 sera from patients recently infected with varicella-zoster virus (VZV) were found to cross-react with human T cell leukaemia virus type 1 (HTLV-1) antigen in the particle agglutination (PA) assay using HTLV-1 antigen-coated gelatin particles. Anti-VZV IgM antibodies were shown to be responsible for this cross-reactivity. Western blot analysis revealed that PA-positive anti-VZV sera reacted with the HTLV-1 gag p19 protein in HTLV-1-infected cells and recombinant p19 protein produced in Escherichia coli. By using a truncated p19, the cross-reactive region was located to the C-terminal 17 amino acids of p19. One oligopeptide derived from the C terminus, PQIPPPYVEPT (amino acids 115 to 125), was capable of inhibiting PA, suggesting that this peptide carries the cross-reactive epitope. A homologous sequence was found in the VZV gene 22 protein by database analysis, and the oligopeptide TNIPPPLALLR (amino acids 1330 to 1340) had the ability to inhibit PA. These findings suggest that some IgM antibodies against the VZV gene 22 protein produced in the early phase of VZV infection are cross-reactive with the HTLV-1 gag p19 protein because they recognize an antigenic determinant containing an IPPP tetrapeptide.

Agglutination Tests↗
PubMed1992

Worldwide distribution of moyamoya disease.

Many cases of spontaneous occlusion of the circle of Willis (moyamoya disease) have been reported in Japan, but the worldwide distribution is unclear. The total number of cases in each country reported in the literature and complications were evaluated. A total of 1063 cases have occurred worldwide excluding Japan. Cases were observed most frequently in Asia and in people of non-Caucasian origin.

Global Health↗
PubMed1992

Changes in major phospholipids of mitochondria during postischemic reperfusion in rat brain.

Major mitochondrial phospholipids were examined in rat brain after 30 minutes of reperfusion following 30- or 60-minute periods of ischemia to examine their changes and explore their relationship to mitochondrial dysfunction during postischemic reperfusion. The amount of phospholipids and the percentage of polyunsaturated fatty acid chains, which tended to decrease during 30 minutes of ischemia, recovered after reperfusion. However, after ischemia lasting for 60 minutes, these parameters did not recover but decreased further, suggesting progressive disruption of phospholipids by phospholipase A2 after reperfusion. These changes were particularly notable in cardiolipin, which is contained specifically in mitochondria. The changes were also closely associated with mitochondrial respiration and respiratory enzyme (cytochrome c oxidase and F0F1-adenosine triphosphatase) activities, which have been known to correlate with the amount of cardiolipin. These results suggest that phospholipid metabolism in mitochondrial membranes is an important factor bearing on the integrity of energy metabolism during postischemic reperfusion.

Adenosine Triphosphatases↗
PubMed1992

A corrected transposition of the great arteries with situs inversus visceralis and cleft palate, but without other cardiac defects.

A 17-year-old female admitted for cleft palate surgery was referred for further evaluation of her cardiac condition. The patient had been diagnosed as dextrocardia at birth, without any cardiac murmurs. She has led a normal life. The apical impulse was felt at the fifth intercostal space at the right mid-clavicular line. The ECG and chest x-rays were strongly suggestive of corrected transposition of the great arteries (CTGA) with situs inversus visceralis. Findings of the two-dimensional and Dopplar echocardiograms showed CTGA with a mild morphologic tricuspid regurgitation without any other complicated cardiac anomalies. In the Japanese literature, 36 CTGA patients without associated cardiac defects have been reported. Of these, four patients revealed dextrocardia. To our knowledge, our patient is the first reported adult case without any cardiac defects, only minimal tricuspid regurgitation, situs inversus totalis and cleft palate.

Abnormalities, Multiple↗
PubMed1992

[A case of idiopathic interstitial pneumonia with cytomegalovirus infection].

A 67-year-old female was admitted to our hospital because of fever, dry cough, and exertional dyspnea. The findings of chest X-ray, transbronchial lung biopsy, and bronchoalveolar lavage were compatible with the diagnosis of idiopathic interstitial pneumonia. Prednisolone was administered and she felt better for a while. However, she developed severe dyspnea, and marked diffuse infiltrative shadows were observed on chest X-ray after 3 months of steroid therapy. In spite of pulse therapy with methylprednisolone, she died of severe respiratory failure. Complement fixation test and IgG antibody enzyme immunoassay for cytomegalovirus were positive, but there was no change the titers between admission and death. IgM antibody was negative. The lung findings at autopsy compatible with usual interstitial pneumonia and diffuse alveolar damage, moreover, cytomegalovirus infection was observed. We consider that recurrent cytomegalovirus pneumonia had been present due to secondary immunodeficiency caused by administration of steroid hormones.

Aged↗
PubMed1979

Liver ribonucleases from the bullfrog, Rana catesbeiana. Purification, properties and changes in activity during metamorphosis.

A major and three minor RNAases exhibiting activity at neutral pH were found in bullfrog liver homogenates. These RNAases were purified to electrophoretic homogeneity. Total purification was 1100 to 1600-fold, and the average recovery was 35%. The molecular weight estimated by gel filtration and SDS-urea-polyacrylamide gel electrophoresis was 12,000 for all the components. An antibody against the major RNAase (component B) reacted with the major RNAase to form a single precipitin line on double immunodiffusion and inhibited the activity of the major RNAase but did not cross-react with the other three components and bovine pancreatic RNAase A. Amino acid analyses revealed that the major RNAase differed markedly from the other three RNAase components in the contents of ten amino acid residues, whereas the minor RNAases were similar to each other. The major RNAase was contained in both frog and tadpole liver and its activity in the liver markedly increased at the metamorphic climax.

Amino Acids↗