Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 469 records · Page 26Linked to original sources

PubMed1993

Creatine kinase-MB protein mass is a better indicator for the assessment of acute myocardial infarction in the lower range of creatine kinase level.

The theoretical and clinical validity of immunochemiluminometric assay of creatine kinase (CK)-MB protein mass was assessed in patients with acute myocardial infarction and the results were compared with those of immunoinhibition assay of CK activity. Serial changes of both CK-MB protein mass and CK-MB activity were analyzed in 20 consecutive patients. In all 312 samples from 20 patients, protein mass and activity of CK-MB showed good correlation. The exponential fitting of the time-value curve of CK-MB protein mass showed a better correlation coefficient than that of CK-MB activity (0.97 +/- 0.02 vs 0.93 +/- 0.07, p < 0.05), indicating that the CK-MB level measured by the immunochemiluminometric assay was less scattered than that measured by the immunoinhibition method. This finding was most evident at lower CK-MB values (< 500 IU/l). The rate of disappearance from serum of CK-MB protein mass was faster than that of CK-MB activity (0.54 +/- 0.23 hr-1 vs 0.28 +/- 0.13 hr-1, p < 0.001). This may indicate that some amount of the CK-MB activity may be inactivated in the early phase of the release into the serum from the necrotic myocardium. Thus, the immunochemiluminometric assay of CK-MB protein mass has superiority in the diagnosis of acute myocardial infarction compared with the immunoinhibition method, especially when the measured CK-MB level is low. This feature may be useful to distinguish a small myocardial infarction from severe ischemia without myocardial necrosis.

Aged↗

PubMed1993

Expression of c-myc mRNA and protein in human endometrial carcinoma; simultaneous study of in situ hybridization and immunohistochemistry.

We examined the c-myc gene at both mRNA and protein levels in tumors of 10 endometrial carcinomas by simultaneous in situ hybridization and immunohistochemistry. Expression of c-myc mRNA was observed in all cases by in situ hybridization. Immunohistochemically, c-myc protein expression was also observed in all cases and immunoreactivity was recognized as nuclear staining. The site of c-myc protein expression was mostly consistent with that of c-myc mRNA expression. While there has been no clear correlation between the expression of c-myc mRNA and/or protein and prognostic parameters so far, this approach will contribute to an understanding of oncogene expression and its biological significance in human gynecological malignancies.

Endometrial Neoplasms↗

PubMed1993

IP3 receptor-mediated spatial and temporal Ca2+ signaling of the cell.

It is now revealed that "intracellular Ca2+ excitation" exists for the generation of spatial and temporal Ca2+ signals based on Ca2+ release from stores. It could be understood in analogy with electrical excitation in the cell surface, the plasma membrane. A local Ca2+ response is generated by the second messenger IP3 following agonist/receptor binding and PI turnover, corresponsing to the receptor potential or excitatory synaptic potential in neurons. The local Ca2+ response triggers a regenerative "intracellular Ca2+ spike" corresponding to the action potential. The regenerative process is the inherent property of the IP3R/Ca2+ release channel which is under positive and negative feedback controls by cytosolic and luminal Ca2+, like activation and inactivation of the voltage-gated Na+ channel. An intracellular Ca2+ spike can be induced artificially by local application of Ca2+, like induction of the action potential by a depolarizing pulse. The Ca2+ spike propagates as a spatial Ca2+ signal throughout the cell, as the action potential does. The excitation is followed by a refractory period. Repeated Ca2+ spikes are generated, depending on the magnitude of stimulus. Interval between Ca2+ spikes depends on the readiness of Ca2+ stores in terms of the sensitivity of the IP3R and extent of Ca2+ accumulation. The cycle of Ca2+ mobilization includes extracellular medium. The intracellular Ca2+ signals are thus frequency-encoded. The temporal pattern of transient Ca2+ pulses may be favorable for accomplishing cellular functions without the side effect of cell toxicity.

Animals↗

PubMed1993

[Prolonged diastolic stunning after unstable anginal attacks].

To evaluate the changes in the left ventricular diastolic filling dynamics after severe myocardial ischemia, serial pulsed Doppler examinations of mitral flow were performed in 10 patients with unstable angina. Peak early and late filling velocities (E and A), the ratio (E/A), the area E (Ei) and A (Ai) and the ratio (Ei/Ai) were measured one, 3, and 7 days and one month after the last ischemic episode. Seven of 10 patients were treated with percutaneous transluminal coronary angioplasty (PTCA), and the same indexes were obtained one, 3, and 7 days and one month after PTCA. E/A and Ei/Ai increased significantly on the 3rd and 7th days, however, no further increase was observed one month after the last ischemic episode and after PTCA. Left ventricular diastolic dysfunction induced by severe myocardial ischemia persisted for several days after the stabilization of myocardial ischemia. After the ischemic episodes were stabilized by administering pharmacological therapy, left ventricular diastolic dynamics were unchanged before and after PTCA. These results indicate that there may be diastolic myocardial stunning in patients with unstable angina.

Angina, Unstable↗

PubMed1993

A system for the continuous measurement of ankle joint moment in hemiplegic patients wearing ankle-foot orthoses.

Plastic ankle-foot orthoses (PAFOs) are now commonly used in clinical practice to supplement the gait disabilities of hemiplegic patients. However, few biomechanical investigation have been performed to analyze the corrective functions of PAFOs. In this paper, a measuring system was developed to assess the effect of dorsi/plantar flexibility of a PAFO on patient's gait. First, a mathematical model of gait with a PAFO was established so that the overall ankle joint moment can be separated into the muscle moment and the corrective moment generated by a PAFO. An experimental AFO, which simulates PAFOs, was specially designed and fabricated to continuously measure the corrective moment of the experimental AFO during gait. A device was also developed to continuously measure the overall ankle joint moment, so that the muscle moment can be estimated from the data obtained by the two devices. The measurement accuracy of the device was evaluated using gait data of eight healthy subjects who simulated hemiplegic gait. The range of the mean +/- 1 SD of the errors, calculated for the eight subjects, fell within +/- 5 Nm, which well compares with the error of commonly used comprehensive gait analysis systems.

Adult↗

PubMed1993

[A giant esophageal ulcer in a hemophiliac with HIV infection].

A 21-year-old man with hemophilia B and human immunodeficiency virus (HIV) infection was admitted with hematemesis and melena. After admission, esophagogram and endoscopy showed a single giant ulcer with ovoid shape and slightly irregular margins in the middle esophagus. Biopsy specimens of the esophageal ulcer showed non-specific granulation and etiology was unknown. Therapeutic trails of famotidine, sodium alginate, acyclovir, and amphotericin B did not result in favorable response. With a combination therapy of dexamethasone and sucralfate, the swallowing pain was rapidly disappeared with gradual improvement of the ulcer. To our knowledge, this is the first report of a giant esophageal ulcer in a HIV infected patient in Japan.

Administration, Oral↗

PubMed1993

Left ventricular filling measured by Doppler echocardiography during dynamic exercise in patients with myocardial infarction.

To assess left ventricular diastolic properties in response to dynamic exercise, mitral inflow velocity integrals were measured by pulsed-wave Doppler echocardiography in ten patients with myocardial infarction and in ten normal subjects, and simultaneous left ventricular pressure was obtained with micromanometry in the patients. Early filling velocity integrals were maintained in the patients during exercise. Late filling velocity integrals were not augmented during exercise in the patients, but were increased in the normal subjects. In the patients, there was an increase in mitral valve opening pressure, left ventricular end-diastolic pressure, and the time constant of left ventricular isovolumic pressure decay. The lowest diastolic pressure and the number of time constants that had elapsed before the lowest diastolic pressure remained unchanged. These results show that in patients with myocardial infarction, early filling is maintained by an increase in driving pressure during exercise, despite incomplete relaxation. Augmentation of late filling, seen in normal subjects, is impaired in patients with myocardial infarction, probably due to an increase in left ventricular stiffness.

Blood Flow Velocity↗

PubMed1993

[Clinical significance of urinary methylguanidine in non-dialyzed patients with chronic renal failure--prediction of progression rate of renal dysfunction].

To clarify a clinical significance of urinary methylguanidine (U-MG, micrograms/dl) in non-dialyzed patients with chronic renal failure, we measured U-MG, urinary creatinine (U-Cr, mg/dl) and serum creatinine (S-Cr, mg/dl), concurrently and continually in 36 out-patients whose S-Cr was over 4.0 mg/dl. Fresh urine sample was obtained and U-MG was measured by an enzymic method. S-Cr concentrations (mean +/- SD) at the initiation of dialysis therapy were comparable in non-diabetics and in diabetics, being 13.4 +/- 4.54mg/dl and 8.23 +/- 1.96mg/dl, respectively, with statistical significance (p < 0.01). U-MG/Cr (micrograms/mg. Cr) values were also different between them, being 9.28 +/- 4.97 in non-diabetics and 5.19 +/- 1.29 in diabetics, but with lesser statistical significance (p < 0.05) than S-Cr. U-MG/Cr correlated well with the terms till the initiation of dialysis therapy (r = 0.7189, p < 0.001), more significantly than S-Cr (r = 0.5506, p < 0.001) in parabolic regression analysis. U-MG/Cr were greatly varied among the 7 patients, although whose S-Cr was nearly the same level (6.0-6.9mg/dl). Most importantly, the tendency was found in these patients that the higher U-MG/Cr, the earlier the renal replacement therapy instituted. These results suggests that U-MG/Cr can be reliable parameter to predict the progression rate of renal failure and to help to know when renal replacement therapy should be instituted.

Adult↗

PubMed1992

Antibody to the inositol trisphosphate receptor blocks thimerosal-enhanced Ca(2+)-induced Ca2+ release and Ca2+ oscillations in hamster eggs.

The sulfhydryl reagent thimerosal enhanced the sensitivity of hamster eggs to injected inositol 1,4,5-trisphosphate (InsP3) or Ca2+ to generate regenerative Ca2+ release from intracellular pools. A monoclonal antibody (mAb) to the InsP3 receptor blocked both the InsP3-induced Ca2+ release (IICR) and Ca(2+)-induced Ca2+ release (CICR). The mAb also blocked Ca2+ oscillations induced by thimerosal. The results indicate that thimerosal enhances IICR sensitized by cytosolic Ca2+, but not CICR from InsP3-insensitive pools, and causes repetitive Ca2+ releases from InsP3-sensitive pools.

Animals↗

PubMed1992

Enduring suppression of hippocampal long-term potentiation following traumatic brain injury in rat.

This study investigated changes in synaptic responses (population spike and population EPSP) of CA1 pyramidal cells of the rat hippocampus to stimulation of the Schaffer collateral/commissural pathways 2-3 h after traumatic brain injury (TBI). TBI was induced by a fluid percussion pulse delivered to the parietal epidural space resulting in loss of righting responses for 4.90-8.98 min. Prior to tetanic stimulation, changes observed after the injury included: (1) decreases in population spikes threshold but not EPSP thresholds; (2) decreases in maximal amplitude of population spikes as well as EPSPs. TBI also suppressed long-term potentiation (LTP), as evidenced by reductions in post-tetanic increases in population spikes as well as EPSPs. Since LTP may reflect processes involved in memory formation, the observed suppression of LTP may be an electrophysiological correlate of enduring memory deficits previously demonstrated in the same injury model.

Animals↗

PubMed1992

Block of Ca2+ wave and Ca2+ oscillation by antibody to the inositol 1,4,5-trisphosphate receptor in fertilized hamster eggs.

The concentration of cytoplasmic free calcium (Ca2+) increases in various stimulated cells in a wave (Ca2+ wave) and in periodic transients (Ca2+ oscillations). These phenomena are explained by inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release (IICR) and Ca(2+)-induced Ca2+ release (CICR) from separate intracellular stores, but decisive evidence is lacking. A monoclonal antibody to the IP3 receptor inhibited both IICR and CICR upon injection of IP3 and Ca2+ into hamster eggs, respectively. The antibody completely blocked sperm-induced Ca2+ waves and Ca2+ oscillations. The results indicate that Ca2+ release in fertilized hamster eggs is mediated solely by the IP3 receptor, and Ca(2+)-sensitized IICR, but not CICR, generates Ca2+ waves and Ca2+ oscillations.

Animals↗

PubMed1992

Molecular basis for Glanzmann's thrombasthenia (GT) in a compound heterozygote with glycoprotein IIb gene: a proposal for the classification of GT based on the biosynthetic pathway of glycoprotein IIb-IIIa complex.

The genetic basis for Glanzmann's thrombasthenia (GT) was elucidated on a compound heterozygote with glycoprotein (GP)IIb gene: an opal mutation at the end of exon 17 (CGA----TGA) results in only a trace amount of GPIIb mRNA, and a splicing mutation at the acceptor site of exon 26 (CAG----GAG) causes an in-frame, exon skipping process from exon 25 to 27. This aberrant transcript encodes a single-chain polypeptide characterized by a 42-amino acid deletion, which includes the proteolytic cleavage site(s) and a unique, proline-rich region at the location corresponding to the carboxyl-terminal of the normal GPIIb alpha-chain. These characteristics are shared by a previously reported defective GPIIb molecule, which is neither assembled with GPIIIa nor transported to the cellular surface. Despite its normal transcription level, expression of the present defective GPIIb molecule was significantly decreased (approximately 6% of the control level). Because the precursor GPIIb molecule is assembled with GPIIIa in the endoplasmic reticulum (ER) and its processing, as well as stability, is dependent on the GPIIIa subunit, the defective GPIIb molecule may be rapidly degraded by the intrinsic quality control system of the ER due to its inability to form a stable heterodimer complex as a consequence of its misfolded structure. Although we did not confirm that the GPIIIa genes of this individual were normal, GPIIIa may be secondarily decreased (approximately 11% of control), because a large part of it could not be complexed, making it vulnerable to proteolysis. To elucidate the molecular basis for GT, we propose here a classification of GT based on the biosynthetic pathway of the GPIIb-IIIa complex.

Base Sequence↗

PubMed1992

Evidence that metalloendoproteases are involved in gamete fusion of Ciona intestinalis, ascidia.

The use of specific inhibitors and substrates of metalloendoproteases provides evidence that in many systems these enzymes are involved in membrane fusion events. In this study, we investigated whether metalloendoproteases are involved in Ciona sperm-egg fusion. In vitro fertilization assays with the metal chelator 1,10-phenanthroline, specific metalloendoprotease substrates, and the vital stain Hoechst 33342 suggested that a Zn(2+)-dependent metalloendoprotease(s) takes part in Ciona sperm-egg fusion. Furthermore, electrophysiological recordings showed that insemination carried out in the presence of either 1,10-phenanthroline or the substrate CBZ-Gly-Phe-NH2 fails to induce fertilization potential or any other change in membrane potential. These results support the hypothesis that in Ciona intestinalis, a metalloendoprotease(s) is functional in gamete fusion.

Animals↗

PubMed1992

Tissue distribution of monomeric glutathione peroxidase in broiler chicks.

It is known that there are two kinds of enzymes which show glutathione peroxidase activity, 'classical' glutathione peroxidase and glutathione S-transferase. Recently, a third enzyme was found, monomeric glutathione peroxidase, in broiler chick liver cytosolic fraction. To gain an insight into the possible physiological role of the monomeric glutathione peroxidase, the distribution of this enzyme in other broiler tissues was studied. The monomeric glutathione peroxidase was found in all tissues examined and in erythrocytes. The percentage of the total glutathione peroxidase activity accounted for by the monomeric enzyme ranged from 4 per cent in erythrocytes to 28 per cent in liver. Livers from three avian and two mammalian species contained the monomeric glutathione peroxidase. The contribution of the monomeric enzyme to total glutathione peroxidase activity with cumene hydroperoxide was high in poultry livers, while only trace monomeric glutathione peroxidase activity was found in mammalian livers. Chick monomeric glutathione peroxidase showed high activity toward phospholipid hydroperoxide. Thus, monomeric glutathione peroxidase might be an important enzyme in reducing membrane lipid hydroperoxides in birds.

Animals↗

PubMed1992

Expression of p53 in human esophageal carcinoma: an immunohistochemical study with correlation to proliferating cell nuclear antigen expression.

Immunolocalization of the nuclear protein p53 tumor suppressor gene product is considered to be one of the best methods of detecting a mutated form of p53. We have studied p53 immunohistochemically by using monoclonal antibody pAb1801 in 15 cases of esophageal squamous cell carcinoma. Immunoreactive p53 was observed in the nuclei of tumor cells in 4% paraformaldehyde-fixed, frozen sections (12 of 15) and paraffin-embedded sections (11 of 15), but not in routinely processed (10% formalin-fixed) specimens. p53 expression was closely correlated with the malignant phenotype, including dysplasia. p53 was not observed in histologically normal mucosa, except in three cases in which scattered immunoreactivity was observed in parabasal and basal cells. Immunostaining of ki67 and proliferating cellular nuclear antigen on adjacent tissue sections revealed that p53 expression was strongly correlated with ki67 and proliferating cellular nuclear antigen in carcinoma and dysplastic cells, but not in normal mucosa, suggesting involvement of the mutated form of p53 in the cell cycle of malignant cells. Immunohistochemical patterns of p53 were not related significantly to clinicopathologic parameters in the cases examined. Therefore, p53 expression was strongly associated with the proliferation of carcinoma cells but not with that of normal cells in esophageal carcinoma.

Aged↗

PubMed1992

The proliferative cell fraction in cytology specimens. A study of human esophageal carcinoma.

Immunostaining of cell cycle-related antigens, especially Ki-67, DNA polymerase alpha, and proliferating cell nuclear antigen, has become an important method to assess the proliferative activity of tumors. These three nuclear antigens were studied by immunohistochemical analysis of cytologic smears. These smears were obtained by scraping the cut surface of 10 cases of esophageal squamous cell carcinoma and were fixed and prepared by different methods. The results were compared with those of tissue sections to apply the immunocytochemical findings of these antigens to cytology specimens. Smears that were placed on Denhardt- or Neoprene-coated slides and subsequently fixed in 4% paraformaldehyde and methanol exhibited the best cell adherence to the slides, had minimal loss of antigenicity, and had good preservation of cell morphologic features for all three antigens examined. The percentage of positive tumor cells in the cytology smear was generally in good agreement with that in the tissue section. For these three antigens, proliferating cell nuclear antigen demonstrated a much higher percentage of positive cells than either Ki-67 or DNA polymerase alpha, in both the smears and the tissue sections. In summary, Ki-67, DNA polymerase alpha, and proliferating cell nuclear antigen can be immunolocalized successfully in cytology smears and may become another parameter to assess the proliferative activity of tumors in the field of diagnostic pathology.

Antigens, Neoplasm↗

PubMed1992

The in-vitro activity of RP 59500 against gram-positive cocci.

RP 59500 was more potent than erythromycin, josamycin, amoxycillin and ciprofloxacin, and as potent as vancomycin, against staphylococci and enterococci. Against streptococci, the activity of RP 59500 was very similar to that of amoxycillin, but was superior to that of erythromycin, josamycin, vancomycin or ciprofloxacin. Compared with the other antimicrobial agents tested, RP 59500 was the most active against erythromycin-resistant Gram-positive cocci.

Amoxicillin↗

PubMed1992

Treatment of Langerhans cell histiocytosis in children with etoposide.

Ten children with Langerhans cell histiocytosis (LCH) were treated with etoposide. For five patients, this was the initial diagnosis. The other five had failed to respond to previous therapies. Etoposide (100 mg/m2) was given intravenously twice a week for 4 weeks, followed by maintenance therapy every 2 to 4 weeks for 2 years. All 10 patients responded to etoposide, and 6 of them (60%) have been in complete remission for 3 to 36 months without any side effects. One patient relapsed with diabetes insipidus, one with a soft tissue mass, and two others developed multiple bone lesions. Chemotherapy with etoposide appears to be effective and safe for the treatment of children with systemic LCH.

Adolescent↗