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Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 631 records · Page 35Linked to original sources
PubMed1993

[Immunohistological investigation of the histological origin and differentiation of pleomorphic adenoma of the parotid gland].

Immunohistological expressions of the cytokeratin (CK) subclass, vimentin, glial fibral antigen protein (GFAP), alpha-smooth muscle actin, and S-100 protein were investigated in pleomorphic adenoma of the parotid gland. In addition, the correlation between immunohistological findings in the normal parotid gland and those in pleomorphic adenoma was examined. Vimentin, S-100 protein, and GFAP, which were not detected in the normal parotid gland, were observed in pleomorphic adenoma. Only CK-1, which was not detected in the normal parotid gland, was expressed intensely in squamous metaplastic lesions of pleomorphic adenoma. All other CK detected in pleomorphic adenoma were also expressed in the normal parotid gland. Therefore, the expression of vimentin, S-100 protein, GFAP, and CK-1 in pleomorphic adenoma is related to oncogenesis. Since most types of CK expression were observed in solid pleomorphic adenoma lesions and all types of CK expression detected in other lesions were included, cellular differentiation between solid and nonsolid lesions was elucidated. According to the pattern of CK subclass expression, the following sequence of differentiation was suggested; solid lesion-->myxoid lesion-->chondroid lesion, solid lesion-->tubular lesion, solid lesion-->myoepithelioid lesion, and solid lesion-->squamous metaplastic lesion. In normal parotid glands, satellite cells around the ductal cells showed all types of CK subclass expression detected in myoepithelial cells, acinus cells, and ductal cells. Since the types and patterns of CK expression in solid lesions of pleomorphic adenoma are the same as those in satellite cells in the normal parotid gland, pleomorphic adenoma seems to originate from satellite cells. If satellite cells in the normal parotid gland are considered to be so-called reserve cells in the bicellular theory, the origin and cellular differentiation of pleomorphic adenoma can be explained in relation to CK subclass expression.

Actins↗
PubMed1993

[Further study of Schellong testing in 152 young females].

Orthostatic dysregulation (OD) generally implies a systemic condition indicating poor circulatory function resulting from autonomic imbalance, which usually appears in a rather young population at or around puberty, predominantly in females. This condition can be recognized from the results of a questionnaire which has been proposed and prepared by the Pediatric OD Study Group of Japan as diagnostic criteria for OD. Schellong testing has also been developed as a screening method to determine OD or orthostatic hypotension. We carried out a survey and analyzed data collected with the questionnaire and Schellong test results among 152 young normal females ranging in age from 18 to 21 years in order to obtain the actual prevalence of OD in these subjects. Among 152 young normal females, 39 (25.7%) were confirmed to have OD based on the questionnaire. Although orthostatic dizziness was relatively common in this series of young females, regardless of the presence or absence of OD (90/152, 59.2%), this symptom, which is listed as one of the 5 major items on the questionnaire, was much more prevalent in subjects with OD (37/39, 94.9%). Similar prevalence patterns for fatigability or unexplained tiredness were also found in subjects with OD (28/39, 71.8%) when compared with total subjects (55/152, 36.2%). As for the positive rate of the Schellong test, subjects with and without OD showed 33.3% and 31.3%, respectively, and this difference was not statistically significant. There was, however, a highly significant difference in the fall in systolic pressure during the Schellong test procedure between subjects without OD and 10 subjects with OD in whom orthostatic dizziness frequently occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Differences of booklet administration from the computer form of MINI personality inventory].

The computer and booklet versions of MINI personality inventories, which contained 250 items, shortened and revised version of MMPI-1, were administered to 81 university students simultaneously. The results of t-test (corresponding sample) showed the significant difference for the raw scores of D, Pd, and Si. The booklet administered MINI gave slightly higher scores than the computerized MINI, however, the correlation analyses showed the salient coefficients between both versions. The analyses of response frequencies for each item showed no significant difference. Results suggested that the slight change in norms was needed for booklet version, because the MINI was standardized by computer form.

Adult↗
PubMed1993

[Co-inactivation of the p53 and RB genes in human hepato cellular carcinoma].

Aberrations of the p53 gene were observed in high frequency in HCCs in China, Mozambique and Japan. Most of the mutations were G to T transversions in codon 249 of the p53 gene in HCCs in China and Mozambique, where aflatoxin B1 was a risk factor. These findings strongly suggest that aflatoxin B1 induced this type of mutations. On the other hand, in Japanese HCCs, no mutation was observed in codon 249, indicating a different cause of HCC development. Pathological analyses revealed that p53 mutations were detected only in advanced HCCs and not in early HCCs. In addition, aberrations of the RB gene were observed in only tumors carrying mutated p53 gene. These results indicate the involvement of at least two tumor suppressor genes in a late stage of hepatocarcinogenesis. Possible mechanisms of HCC formation are discussed.

Aflatoxin B1↗
PubMed1993

[A surgical case of cor triatriatum].

A case report of a variant type of cor triatriatum was presented. The patient was critically ill when she was admitted to our hospital. An emergent operation was performed under the cardio-pulmonary bypass. The right atrium was incised, then the interatrial septum was incised. Inspection revealed an abnormal membrane in the left atrium. All the pulmonary veins were drained into the accessory chamber. The left atrial appendage was also connected with the accessory chamber. The membrane was not including the mitral valve tissue. It was resected completely. Postoperative course was uneventful.

Cardiopulmonary Bypass↗
PubMed1993

[A case report: partial anomalous pulmonary venous return of the left lung communicating with the left atrium through the aberrant vein].

A rare case with partial anomalous pulmonary venous return was presented. The left superior pulmonary vein was drained into the left innominate vein via a common vertical vein and it also communicated with the left atrium via a small aberrant vein. All the other pulmonary veins were normally drained into the left atrium. The surgical repair was performed through the midline sternotomy. The junction of the vertical vein and the left innominate vein was ligated with slight elevation of the pressure in the left pulmonary vein. Under the cardiopulmonary bypass, the secundum atrial septal defect was closed by direct sutures. The postoperative course was uneventful and there was no pulmonary congestion in the left upper lung field.

Child↗
PubMed1993

Characterization of C3a anaphylatoxin receptor on guinea-pig macrophages.

We have characterized a C3a receptor on guinea-pig macrophages by 125I-C3a binding and functional responses. Scatchard analysis applied to the 125I-C3a binding to guinea-pig macrophages revealed the existence of two receptor classes; a high-affinity class with approximately 0.63 x 10(5) binding sites/cell with a Kd = 2.7 nM, and a relatively low-affinity class with approximately 1.2 x 10(5) binding sites/cell with a Kd = 51 nM. The binding of C3a to macrophages was totally blocked when there was an excess of C3a. C3a triggered a transient intracellular Ca2+ ([Ca2+]i) mobilization in macrophages, which was accompanied by homologous desensitization. C3a was also capable of generating O2- from macrophages. The C3a-induced Ca2+ response and O2- generation were not detected in the pertussis toxin-treated macrophages, suggesting that G proteins are coupled with the C3a receptors of macrophages. Although the C3a-induced O2- generation was inhibited by staurosporine, it was more resistant to staurosporine than phorbol 12-myristate-13-acetate (PMA)-induced O2- generation, suggesting that a protein kinase distinct from protein kinase C may be associated with the C3a receptor.

Animals↗
PubMed1993

[Problems in DNA ploidy analysis using flow cytometry--influences from contaminant mononuclear cells].

The present study was undertaken to examine the influences of excessive contamination by lymphocytes on the flow cytometric analysis of DNA ploidy of head and neck cancers. Although lymphocytes which contaminate test cells can serve as an internal control (2C), an excess of these lymphocytes can mask the aneuploid peak of cancers. This tendency was particularly prevalent in well-differentiated squamous cell carcinoma. In some cases, most of the cells isolated from tumor-positive HE-stained tissue samples were lymphocytes. This is probably because lymphocytes are likely to survive the cell-isolating procedure, whereas keratocytes are likely to be destroyed during it. If samples excessively contaminated by lymphocytes are subjected to flow cytometry, the aneuploid peak of cancer cells is low relative to the 2C peak, possibly causing an erroneous judgment of diploid. Cytofluorometry, in which a smear of test cells is observed directly to quantify the DNA of cancer cells alone, was useful in detecting lymphocyte-masked aneuploid cells.

Carcinoma, Squamous Cell↗
PubMed1993

[Surgical treatment of unroofed coronary sinus].

We have experienced four cases of unroofed coronary sinus. Three cases were partial forms and one case was a complete form. Two of them were successfully diagnosed before operation. Surgical viewpoints were discussed. In the absence of LSVC, the coronary sinus defect may be simply closed. In the cases with PLSVC, several types of repair were discussed. It has been reported that this defect is usually associated with simple or complex cardiac malformations, including tricuspid atresia or tetralogy of Fallot. In our case with TA, oversight of this anomaly before and during operation resulted in the urgent reoperation. A surgeon should always keep in mind this anomaly, even if the coronary sinus is not large.

Adolescent↗
PubMed1992

[MR imaging of degenerative lumbar disc disease emphasizing on signal intensity changes in vertebral body].

Magnetic resonance imaging was performed in 400 patients with degenerative disc disease. Signal changes and their sites in the vertebral body were classified and referred to narrowing of the intervertebral disc space. MR findings were compared with those of plain roentgenograms of the lumbar spine. Signal changes in the vertebral body were noted in 83 cases (102 vertebral bodies). Low-intensity abnormality on both T1- and T2-weighted images (WI) was the most common finding, and was most frequently seen at the end plate and/or the angle. These changes were correlated with narrowing of the disc space and osteosclerosis on the plain roentgenogram of the lumbar spine. Signal changes occasionally occurred in the inner region of the vertebral body, and these lesions tended to show a high-intensity abnormality on T1-WI. We conclude that signal changes in degenerative disc disease are not specific, but are sometimes difficult to distinguish from the signal changes in other conditions such as spinal tumor or bone marrow disorder.

Humans↗
PubMed1992

Ornithine decarboxylase is degraded by the 26S proteasome without ubiquitination.

Ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis, is the most rapidly turned over mammalian enzyme. We have shown that its degradation is accelerated by ODC antizyme, an inhibitory protein induced by polyamines. This is a new type of enzyme regulation and may be a model for selective protein degradation. Here we report the identification of the protease responsible for ODC degradation. Using a cell-free degradation system, we demonstrate that immunodepletion of proteasomes from cell extracts causes almost complete loss of ATP- and antizyme-dependent degradation of ODC. In addition, purified 26S proteasome complex, but not the 20S proteasome, catalyses ODC degradation in the absence of ubiquitin. These results strongly suggest that the 26S proteasome, widely viewed as specific for ubiquitin-conjugated proteins, is the main enzyme responsible for ODC degradation. The 26S proteasome may therefore have a second role in ubiquitin-independent proteolysis.

Adenosine Triphosphate↗
PubMed1992

Structural requirements for duodenal permeability of heparin-diamine complexes.

We have compared the physico-chemical behaviors alone and in the presence of a synthetic bilayer membrane, in aqueous solution and the bioavailability after intraduodenal administration to rabbits, of the two heparin diamine salts ITF-300 and ITF-331 with those of the heparin-amine salt ITF-1175. The three salts have similar structures but different characteristics of compounds tend to form aggregates in solution, but at different critical concentrations. The compounds induce fusion of single-walled vesicles of a synthetic peptide lipid into multi-walled lamellae. The minimal concentrations of the compounds required for the formation of such lamellae differ. This behavior in solution explains the differences in absorption in the animal model. This makes it possible to correlate enhanced heparin bioavailability with the structural nature of the diamine counter-ions used to prepare heparin salts.

Animals↗
PubMed1992

Measurement of plasma membrane potential in isolated rat hepatocytes using the lipophilic cation, tetraphenylphosphonium: correction of probe intracellular binding and mitochondrial accumulation.

The lipophilic cation tetraphenylphosphonium (TPP+) has been extensively utilized as the probe for the membrane potential (Vm) in various cells. For application to mammalian cells, however, two serious problems require resolution: (1), correction of TPP+ binding to intracellular constituents and (2), estimation of the considerable TPP+ accumulation in mitochondria. We propose here a simple corrective method for the TPP+ binding and its accumulation. TPP+ distribution is assumed as: (1), two compartments (a cytosolic and a mitochondrial space); (2), a proportional relationship between TPP+ bound amount and its unbound concentration in each compartment. We theoretically derived the simple equation: Vm = - RT/F ln(C/Mphys ratio/C/Mabol ratio) where R, T and F have their usual thermodynamic significance. Here, the C/M ratio is defined as the ratio of TPP+ concentration of apparent intracellular to extracellular space. The suffixes phys and abol, respectively, mean the physiological and solely Vm-abolished conditions. This equation was checked with hepatocytes, because estimating hepatocytes Vm with TPP+ distribution is not considered possible because of the relatively high mitochondrial content. The selective Vm abolition was achieved by permeabilization with 20 microM of amphotericin B. The Vm value was, thus, estimated to be -38.6 +/- 0.3 mV, compatible with those obtained with microelectrodes in other laboratories. Vm in hepatocytes is composed of transmembrane K+ diffusion potential (-20.6 +/- 0.3 mV) and electrogenic Na+/K(+)-ATPase (-19.6 +/- 0.4 mV). Addition of rheogenic L-alanine caused a transient but significant depolarization (from control to -34 +/- 0.3 mV). These results taken together indicate that hepatocyte Vm can be accurately determined with the present simple method, so that it may possibly be applicable to the evaluation of Vm in other mammalian cells.

Amphotericin B↗
PubMed1992

Biological role of an arginine residue present in a histidine-rich peptide which inhibits hemagglutination of Porphyromonas gingivalis.

Inhibitory effects of synthetic fragments in histatin 8, having the sequence Lys-Phe-His-Glu-Lys-His-His-Ser-His-Arg-Gly-Tyr, on hemagglutination by Porphyromonas gingivalis 381 were examined. The hemagglutinating activity was reduced much more by the peptide Lys-His-His-Ser-His-Arg-Gly-Tyr than by the peptides Lys-His-His-Ser-His and/or Lys-Phe-His-Glu-Lys. These results suggest that the arginine residue may have an important role in the inhibition of hemagglutination by P. gingivalis.

Amino Acid Sequence↗
PubMed1992

Aberrations of the p53 tumor suppressor gene in human non-small cell carcinomas of the lung.

Aberrations of the p53 gene in 115 surgical specimens of non-small cell carcinomas of the lung were examined by single-strand conformation polymorphism analysis of polymerase chain reaction products. Structural abnormalities of the p53 gene were observed in 60 tumors (52%), i.e., 8 of 14 large cell carcinomas, 24 of 58 adenocarcinomas, 25 of 37 squamous cell carcinomas, and 3 of 6 adenosquamous carcinomas. Direct sequencing of abnormal DNA fragments revealed 45 single-base substitutions, 9 deletions or insertion of a short nucleotide sequence, and 3 two-base substitutions in 57 tumors. In the other 3 tumors, loss of one of the p53 alleles was observed, with no mutation in the other allele. Allelic loss of the p53 gene was observed in 14 of 43 informative cases (33%), and in 11 of the 14 cases the remaining allele was mutated. The aberrations of the p53 gene were not limited to a particular histological type or clinical stage. Their high frequency suggests that they were involved in the genesis of non-small cell carcinomas of the lung. The mutation frequency (46%) of the p53 gene in tumors carrying mutated ras genes was essentially the same as the overall frequency in lung cancers, suggesting that accumulation of mutations in these two genes in a tumor is a random phenomenon.

Base Sequence↗
PubMed1992

Destabilization of ornithine decarboxylase by transfected antizyme gene expression in hepatoma tissue culture cells.

The degradation of ornithine decarboxylase (ODC) is stimulated by polyamines in a protein synthesis-dependent manner. It has been suggested that antizyme, an ODC-inhibiting protein induced by polyamines, is involved in the process of polyamine-stimulated ODC decay. In this study, we investigated the direct effect of antizyme on ODC decay in hepatoma tissue culture (HTC) cells. A truncated rat antizyme cDNA, Z1, was inserted into an expression vector at a site under the control of a glucocorticoid-inducible promoter and transfected into HTC cells. In the transfected cells dexamethasone increased the amount of Z1 mRNA and induced active antizyme in the absence of exogenous polyamines. When dexamethasone was added to cells with a high level of ODC, rapid decays of ODC activity and protein were elicited after a lag time. Cycloheximide abolished the effect of dexamethasone. These effects of dexamethasone were not observed in control HTC cells transfected with the chloramphenicol acetyltransferase gene. This study indicated that, once induced, antizyme stimulated ODC degradation independently of polyamines and strongly supported our previous hypothesis that the ODC decay-accelerating action of polyamines is mediated by antizyme.

Animals↗