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Biomedical subjects

H Miyata

Publications and source records attributed to H Miyata.

At least 415 records · Page 23Linked to original sources
PubMed1981

Amphoteric charge distribution at the enzymatic site of 1,N6-ethenoadenosine triphosphate-binding heavy meromyosin determined by dynamic fluorescence quenching.

The features of the charge distribution in the vicinity of the ATP-binding site of heavy meromyosin (HMM) were investigated by the technique of dynamic fluorescence quenching. Instead of ATP, 1,N6-ethenoadenosine triphosphate (epsilon-ATP), a fluorescent derivative of ATP, was attached to the ATP-binding site in the presence of an ATP-regenerating system. The I- ion and acrylamide were used as negative- and zero-charged quenchers. In addition to these quenchers, we used the TI+ ion, which has recently been found to be a highly efficient quencher with positive charge, and to be generally applicable to fluorescence-labeled proteins. The Stern-Volmer quenching constants of TI+ and I- for epsilon-ATP bound to HMM both decreased with increasing ionic strength of the solvent. This result means that there is an electrostatic attractive force between the fluorophore ad both TI+ and I-. On the other hand, the Stern-Volmer quenching constant of acrylamide was not significantly affected by a change in ionic strength. This result confirms that no significant change in protein conformation in the vicinity of the epsilon-ATP-binding site of HMM occurs with change in ionic strength. In order to interpret these results, we propose a model in which a positive charge is located on one side of the epsilon-adenine ring and a negative charge is located on the opposite side. The negative charge is attributed to the phosphate group in epsilon-ATP and positive one is probably attributable to a lysyl residue in the polypeptide chain of HMM.

Adenosine Triphosphate↗
PubMed1981

Transient remission of juvenile rheumatoid arthritis after measles.

A 4-year-old Japanese girl with systemic juvenile rheumatoid arthritis had an attack of measles. On the day following the first signs of measles she became afebrile and free of joint pain even though aspirin therapy was discontinued. The remission lasted for 10 days. It appears that the measles virus infection may have been responsible for the brief remission in this patient. The observation of a remission of juvenile rheumatoid arthritis after measles is extremely rare.

Arthritis, Juvenile↗
PubMed1981

Dynamic characteristics of the otolithic oculomotor system.

Vertical eye tracking test, up-down test, and running test in the dark and light were carried out to obtain Bode plots of transfer function of the opto-oculomotor, otolithic oculomotor, and opto-otolithic oculomotor systems. 1. The gain and phase of the opto-oculomotor system obtained from the vertical eye tracking test were flat in a frequency range of 0.3 to 1.0 Hz. 2. During the up-down test in the dark, the gain of the otolithic oculomotor system linearly increased at the rate of 20 dB/decade with an increase of frequency from 0.7 to 5 Hz. 3. During the up-down test in the light, the gain and phase were flat in a frequency range of 0.3 to 2.5 Hz. 4. The transfer function calculated with vertical head acceleration as input and vertical eye movement as output in the running test in the dark was similar to that in the light. The gain linearly decreased at the rate of 40 dB/decade with increase of frequency from 0.3 to 3.0 Hz. During running, eye displacement is almost in proportion to the head displacement in both dark and light. In daily, active movement such as running, eye movement proportional to head displacement appears without collaborative action of the opto-oculomotor system. 5. All five patients with bilateral loss of labyrinthine excitability exhibited a similar opto-oculomotor response to that of normal subjects. Three of the five patients did not show any eye movement corresponding to head movement in the up-down test in the dark. However, two patients showed a periodic eye movement in the same test, indicating dispersion of the gain and phase values. 6. These patients exhibited a rhythmic eye movement corresponding to head movement in the running test in the dark and light. However, values of gain and phase obtained in both tests were cultured. The variations in gain obtained from the running test in the light were observed in frequency ranges above and below 1 Hz.

Adult↗
PubMed1981

Plasma factor XIII levels in children with renal disease.

Plasma levels of coagulation factor XIII determined quantitatively were found to have a tendency to be decreased in more severely affected cases of acute poststreptococcal glomerulonephritis and Henoch-Schönlein nephritis, and found to be decreased in patients with rapidly progressive glomerulonephritis and chronic renal failure in comparison with normal controls. It seems that the degree of decrease in factor XIII reflects the intensity of glomerular damage. In contrast, the patients with the nephrotic syndrome showed significant elevation of plasma factor XIII levels and it was closely correlated with the increase in serum triglycerides. The elevation of factor XIII levels in the nephrotic syndrome is suggested to be mainly attributed to enhanced protein synthesis in connection with urinary loss of proteins.

Adolescent↗
PubMed1981

Hemoglobin Miyashiro (beta 23[B5] val substituting for gly) an electrophoretically silent variant discovered by the isopropanol test.

A new unstable hemoglobin was discovered in a Japanese boy without any signs of hemolytic disease during screening of patients by the isopropanol test. The abnormal hemoglobin was found in three generations. This slightly unstable hemoglobin could not be separated from Hb A by electrophoresis. All carriers showed an increased whole blood oxygen affinity. Structural studies demonstrated a previously unreported amino acid substitution, beta 23[B5] valine substituting for glycine. This new unstable variant has been named Hb Miyashiro.

Adolescent↗
PubMed1981

Human hepatocellular carcinoma and putative precancerous disorders: their enzyme histochemical study.

An enzyme histochemical study was performed to investigate abnormal enzyme activity in human hepatocellular carcinoma (HCC) and, by application of these staining reactions to noncancerous liver disorders, to clarify the true nature of putative percancerous lesions. The enzyme activity of hepatocytes in cirrhotic livers, hepatitis B virus (HBV)-positive cells, and dysplastic liver cells was investigated. Although the tumor cells in HCC gave an intensively positive reaction for gamma-glutamyl transpeptidase activity at the cytoplasm and the whole-cell membrane, they were essentially deficient in glucose-6-phosphatase, alkaline phosphatase, acid phosphatase, and nonspecific esterase activities. Cirrhotic liver showed loss of the orderly zonal difference of enzyme activity that is present in normal liver. However, a pattern of enzyme deviation similar to that of HCC was not recognized anywhere. Neither HBV-positive hepatocytes nor dysplastic liver cells were shown enzymatically to be direct precusors of HCC.

Acid Phosphatase↗
PubMed1981

Alterations of host resistance to Listeria monocytogenes in tumour-bearing mice and the effect of Corynebacterium parvum.

In tumour (fibrosarcoma)-inoculated mice, alterations of host resistance to Listeria monocytogenes following tumour growth were examined. Non-immune macrophage-mediated antibacterial resistance was severely suppressed up to day 4 or so after tumour inoculation, but was enhanced thereafter. On the other hand, T cell-mediated immune resistance retained the control level up to day 7 or so, but was suppressed thereafter. Suppression of macrophage-mediated antibacterial resistance was not observed if the tumour-bearing mice had been pretreated with Corynebacterium parvum. Moreover, this suppression of macrophage-mediated resistance was attributable to the presence of a serum factor that interferes with the function of free macrophages but not with that of resident macrophages. The ability of this serum factor to suppress macrophage-mediated antibacterial resistance, however, was not reduced by C. parvum administration.

Animals↗
PubMed1980

Lysis of growing fissin-yeast cells induced by aculeacin A, a new antifungal antibiotic.

Cells of Schizosaccharomyces pombe grown in the presence of aculeacin A, a peptide antibiotic, were lysed resulting the death of cells. Under high osmolarity, the cellular lysis induced by aculeacin A was considerably reduced. The use of synchronous-culture systems distinguished cell elongation from cell division revealed that the sites of aculeacin A-induced lysis on the fission yeast were the end(s) and the cell plate region, corresponded to the regions of the cell wall synthesis. Aculeacin A-resistant survivors exhibited morphological alterations which were swollen at one or both ends of the cell and appeared drumstick or dumbbel like; the wall of the bulge region was observed to be stained with a fluorescent brightner, as well as that of the cell plate region. These effects of aculeacin A are discussed as compared with effects of 2-deoxy-D-glucose.

Antifungal Agents↗
PubMed1980

Liver lipids in Letterer-Siwe disease.

A case of Letterer-Siwe disease in a thirteen-month-old girl with markedly swollen gums, an enlarged liver, and seborrhoic skin eruptions is reported. She died from pyopneumothorax in spite of treatment with prednisolone and vinblastine. Analysis of hepatic lipids showed that there was remarkable increase in free fatty acid, which is not seen in normal human liver. Cholesterol ester was also accumulated in the liver tissue. However, the concentrations of phospholipids and glycerides were low and lysophospholipid was found. It is assumed that there was increased intracellular lipolysis in the proliferating reticuloendothelial cells.

Cholesterol Esters↗
PubMed1980

A 6-year-old boy having hepatocellular carcinoma associated with hepatitis B surface antigenemia.

Hepatocellular carcinoma associated with hepatitis B virus (HBV) infection occurring in a boy who was 6 years 2 months old is reported. The patient is thought to have been infected with HBV by exchange blood transfusion (horizontal infection) in the neonatal period. Jaundice appeared eight months after birth. He was subsequently treated and follow-up with a diagnosis of hepatitis B surface (HBs) antigen (Ag)-positive chronic persistent hepatitis. His mother and other family members were HBsAg-negative. Postmortem examination revealed a multinodular growth of hepatocellular carcinoma of trabecular and solid pattern, mainly of the right lobe, complicated with mild fibrosis of the liver. Numerous HBsAg-positive hepatocytes demonstrated by orcein staining and the indirect immunoperoxidase method were present in the noncancerous area. This hepatocellular carcinoma is considered to have occurred within six years two months after HBV infection and not to have been associated with liver cirrhosis. The present case may be valuable for assessing the oncogenic properties of HBV and the incubation period of HBV infection before it develops into hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1980

Autoimmune haemolytic anaemia in an asymptomatic carrier of hepatitis B virus.

A patient with 'warm type' autoimmune haemolytic anaemia (AIHA) was also an asymptomatic carrier of hepatitis B virus (HBV). Although the direct antiglobulin test became negative after the anaemia had recovered spontaneously, antigenaemia of HBV persisted and the serum transaminase level remained normal or borderline. AIHA has not previously been described in association with the asymptomatic carrier state of HBV.

Anemia, Hemolytic, Autoimmune↗
PubMed1980

Characteristics of resistance to Listeria monocytogenes enhanced by Corynebacterium parvum in mice.

In mice pre-treated with Corynebacterium parvum, Listeria monocytogenes was cleared rapidly from the blood and bacterial growth in the liver and spleen was inhibited effectively during the early phase of infection. This enhanced resistance could be transferred with peritoneal exudate cells (PEC) but not with non-adherent spleen cells. In spite of earlier elimination of bacteria, pre-treated mice developed lower levels of delayed-type hypersensitivity (DTH) to bacteria than untreated immune control mice, but the control levels of DTH could be reached by increasing the challenge dose of bacteria in C. parvum-pre-treated mice. Additionally, C. parvum did not inhibit the expression of antibacterial immunity when immune mice were rechallenged. It appeared that the active suppression of the T-cell mediated immune response by C. parvum-activated macrophages was not seen during the course of L. monocytogenes infection, and that the lower levels of DTH seen in mice pre-treated with C. parvum were attributable to an insufficient antigenic stimulus following the accelerated elimination of bacteria by non-specifically activated macrophages during the early phase of infection.

Animals↗