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Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 739 records · Page 41Linked to original sources
PubMed1991

Inactivation of the retinoblastoma gene in a human lung carcinoma cell line detected by single-strand conformation polymorphism analysis of the polymerase chain reaction product of cDNA.

Combined use of a simple, sensitive method of DNA analysis of nucleotide substitutions, namely, single-strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP), and the reverse transcriptase reaction (RT) is an effective method for mRNA analysis. We used this RT-PCR-SSCP method to detect abnormal retinoblastoma (RB) gene transcripts in human tumor cell lines. Results showed the presence of two types of RB gene transcripts in a giant cell lung carcinoma cell line Lu65: a minor mRNA species with a base substitution that created a stop codon in the nucleotide sequence corresponding to exon 2 of the gene, and a major species of mRNA without the nucleotide sequence corresponding to that of exon 2. PCR-SSCP analysis of the genomic DNA also revealed that Lu65 cells contained the mutated RB allele, but not the normal allele. These results suggested that in Lu65 cells, both RB alleles were inactivated. The transcript without the exon 2 sequence, probably due to alternative splicing, was also found in all the other human cells examined, as a very minor species.

Base Sequence↗
PubMed1991

[A study of resistance to antiseptics of methicillin resistant Staphylococcus aureus (MRSA) in gastroenterological surgery].

Highly methicillin-resistant Staphylococcus aureus (H-MRSA, MIC greater than 100 micrograms/ml) was prevalent from 1986 in our institution. The failure of povidone-iodine to reduce the prevalence of MRSA led us to choose chlorhexidine-ethanol solution as an antiseptic, and then the isolation frequency of H-MRSA decreased significantly in 1988. When H-MRSA began to increase again recently, we studied the resistance to antiseptics of MRSA in order to investigate the cause of this re-increase. Common antiseptics were tested against 45 strains of H-MRSA and 22 strains of methicillin sensitive S. aureus (MSSA, MIC less than 12.5 micrograms/ml). Dilute preparations (1:100) of povidone-iodine and chlorhexidine-ethanol solution were more effective on H-MRSA than the other antiseptics. Though there was no significant difference between H-MRSA and MSSA in their sensitivity to povidone-iodine, the killing of H-MRSA strains was more delayed than the killing of MSSA strains in chlorhexidine. Even after a 120-second exposure, 13.3% of H-MRSA strains were resistant to chlorhexidine (more than 1000 colonies were recovered). These highly chlorhexidine-resistant strains have been isolated since 1987 when we chose chlorhexidine-ethanol solution as the antiseptic in our institution. Therefore we suspect that the acquirement of resistance to antiseptics by H-MRSA caused the re-increase of this strain.

Anti-Infective Agents, Local↗
PubMed1990

Primate's p53 inhibits SV40 DNA replication in vitro.

Previous reports indicated that rodent p53 inhibits simian virus 40 (SV40) DNA replication in vitro as well as in vivo while that from primate cells does not (1-4). Here we report the evidence that p53 of primate origin also inhibits SV40 DNA replication in vitro. p53-SV40 large tumor antigen (T antigen) complex purified from SV40 infected COS-1 cells had little replication activity and inhibited SV40 DNA replication in vitro. These results suggest that inhibition of SV40 DNA replication by p53 should be regarded as general property of the protein and does not determine the mode of species specific replication of SV40 DNA.

Animals↗
PubMed1990

Effects of intrathecal administration of thyrotropin releasing hormone and its analogue, DN1417, on plasma glucose and catecholamine levels in conscious rats.

Effects of intrathecal (i.t.) administration of TRH and the TRH analogue, DN1417, on plasma catecholamines and glucose levels were studied in conscious male rats. The i.t. administration of TRH (0.6 and 3 nmol) at the T8-10 vertebral level resulted in a dose-related increase in epinephrine (E), norepinephrine (NE), and glucose levels, which was suppressed by prior administration of the ganglionic blocker, hexamethonium (1.5 mg/100 g b. wt.). I.t. administration of TRH (3 nmol) caused small increases in plasma E and glucose at the C7-T1 vertebral level, but it did not change plasma E, NE and glucose levels at the sacral level. DN1417 (3 nmol) administered i.t. at the T8-10 or C7-T1 vertebral level had a more potent and long-lasting effect in stimulating the release of E than TRH. These findings suggest that TRH may act on sympathetic preganglionic neurons at the T7-10 spinal levels and stimulate the release of catecholamines from the adrenal medulla.

Animals↗
PubMed1990

DNA helicase and nucleoside-5'-triphosphatase activities of polyoma virus large tumor antigen.

Polyoma virus large tumor antigen (PyV T antigen) has been purified to near homogeneity by immunoaffinity column chromatography. We have detected DNA helicase and ATPase (nucleoside-5'-triphosphatase) activities in the purified PyV T antigen fraction and characterized these activities. The ATPase activity was stimulated about 2-fold by poly(dT), which was the most effective stimulator among the synthetic polynucleotides tested. Natural nucleic acids, such as calf thymus native and heat-denatured DNA, and single-stranded circular fd DNA were also effective, but the degree of stimulation was less than 1.5-fold. The basal and poly(dT)-stimulated ATPase activities showed similar preference for nucleoside 5'-triphosphates, requirement for divalent cations, and pH optima. The preference for nucleoside 5'-triphosphates was ATP, dATP greater than CTP, UTP much greater than GTP. The only difference observed between the two activities was salt sensitivity. The basal ATPase activity was resistant to KC1 up to 300 mM. In contrast, poly-(dT)-stimulated activity was reduced to the level of basal activity at 300 mM KC1. DNA helicase activity required divalent cations and was dependent on hydrolysis of ATP. The activity showed similar preference for nucleoside 5'-triphosphates, requirement for divalent cations, and pH optimum as the two ATPase activities, and the salt sensitivity of DNA helicase activity was similar to that of poly(dT)-stimulated ATPase activity. The helicase activity was inhibited competitively by the addition of single-stranded or double-stranded DNA, and a relatively high inhibitory activity was observed with poly [d(A-T)]. The PyV T antigen helicase was found to migrate in the 3' to 5' direction along the DNA strand to which the protein bound.

Adenosine Triphosphatases↗
PubMed1990

Isolation of temperature-sensitive cell cycle mutants from mouse FM3A cells. Characterization of mutants with special reference to DNA replication.

A large number of mutants that are temperature sensitive (ts) for growth have been isolated from mouse mammary carcinoma FM3A cells by an improved selection method consisting of cell synchronization and short exposures to restrictive temperature. The improved method increased the efficiency of isolating DNA ts mutants, which showed a rapid decrease in DNA-synthesizing ability after temperature shift-up. Sixteen mutants isolated by this and other methods were selected for this study. Flow microfluorometric analysis of these mutants cultured at a nonpermissive temperature (39 degrees C) for 16 h indicated that five clones were arrested in the G1 to S phase of the cell cycle, six clones were in the S to G2 phase, and two clones were arrested in the G2 phase. The remaining three clones exhibited 8C DNA content after incubation at 39 degrees C for 28 h, indicating defects in mitosis or cytokinesis. These mutants were classified into 11 complementation groups. All the mutants except for those arrested in the G2 phase and those exhibiting defects in mitosis or cytokinesis showed a rapid decrease in DNA synthesis after temperature shift-up without a decrease in RNA and protein synthesis. The polyomavirus DNA cell-free replication system, which consists of polyomavirus large tumor antigen and mouse cell extracts, was used for further characterization of these DNA ts mutants. Among these ts mutants, only the tsFT20 strain, which contains heat-labile DNA polymerase alpha, was unable to support the polyomavirus DNA replication. Analysis by DNA fiber autoradiography revealed that DNA chain elongation rates of these DNA ts mutants were not changed and that the initiation of DNA replication at the origin of replicons was impaired in the mutant cells.

Animals↗
PubMed1990

Superior vena cava syndrome as a complication of DDD pacemaker implantation.

A 75-year-old man was admitted to our hospital because of swelling of the face and neck 6 months after implantation of a two-chamber pacemaker. Digital subtraction angiography showed total occlusion of the superior vena cava vein and well-developed collateral channels. After thrombolytic therapy, facial swelling disappeared. Digital subtraction angiography performed after thrombolytic therapy revealed a recanalization of the superior vena cava.

Aged↗
PubMed1990

Microscopic incipient hepatocellular carcinoma found incidentally in a routine liver biopsy specimen.

A microscopic atypical focus suggestive of hepatocellular carcinoma is reported. The lesion, 0.3 mm in diameter, was found by chance in a liver biopsy specimen taken from a cirrhotic patient; it was characterized histologically by cytoplasmic basophilia, hypercellularity (high nucleus-to-cell ratio) and microacinar structures. The reticulin framework of the focus was relatively sparse compared with the surrounding noncancerous area. The focus had developed in a regenerative nodule apparently no different from other regenerative nodules of the cirrhosis and showed no accompanying preneoplastic lesion such as adenomatous hyperplasia. A thorough search for the primary lesion, including ultrasonographic imaging and superselective hepatic arteriography, demonstrated no mass lesion in the liver. Therefore, the lesion may have been an incipient de novo hepatocellular carcinoma, and this may be the first report of such a lesion discovered in a biopsy sample.

Adult↗
PubMed1990

Glycoconjugate histochemistry in the glycocalyx of guinea pig middle ear mucosa.

An attempt was made to determine the composition of oligosaccharide side chains in the apical cell surface glycocalices of the middle ear epithelium. This glycoconjugate is located on the innermost luminal surface, but its function is still unknown. The lectins evaluated included Triticum vulgare, Canavalia ensiformis, Maclura pomifera, Arachis hypogaea, Ricinus communis I (RCA-I), and Limax flavus. The staining results obtained with the six different lectin probes in the Lowicryl K4M-embedded guinea pig middle ear mucosa suggest that the glycocalyx contains beta-D-N-acetylglucosamine, sialic acid, and beta-D-galactose in the major carbohydrate moiety. The present study also indicates that a polarity exists on the cell surfaces in the distribution pattern of the carbohydrate component, especially those of beta-galactosyl residues, as revealed by RCA-I binding. This may imply functional separation of the epithelial cells.

Animals↗
PubMed1990

Hypoplastic left heart syndrome with premature closure of foramen ovale: report of an unusual type of totally anomalous pulmonary venous return.

We report on a case of hypoplastic left heart syndrome (HLHS), associated with premature closure of the foramen ovale and an unusual type of totally anomalous pulmonary venous return. The existence of an anomalous connection of the right upper pulmonary vein to the superior vena cava-right atrial (SVC-RA) junction and the existence of the anomalous intrapulmonary venous channel between right upper and lower pulmonary vein allowed all the pulmonary blood to drain into the SVC-RA junction, whereas she had only partially anomalous pulmonary venous connection. The several intrapulmonary venous channels helped to delay the progression of pulmonary venous obstruction. Chromosomal analysis revealed that the patient had XO Turner syndrome. We conclude that all infants with HLHS should be carefully evaluated for the existence of anomalous pulmonary venous return. Two-dimensional Doppler echocardiography is one of the most useful techniques for evaluating such anomalies.

Abnormalities, Multiple↗
PubMed1990

Use of bovine lung heparin to obviate anaphylactic shock caused by porcine gut heparin.

Intracardiac repair in a 7-year-old girl with tetralogy of Fallot was hampered because of an anaphylactic reaction with cardiopulmonary collapse caused by porcine gut heparin. This patient had an extremely rare case of hypersensitivity to porcine gut heparin but not to bovine lung heparin. Uneventful radical operation could be performed with the use of bovine lung heparin for systemic heparinization during cardiopulmonary bypass.

Anaphylaxis↗
PubMed1990

Inhibitory effects of synthetic histidine-rich peptides on haemagglutination by Bacteroides gingivalis 381.

The haemagglutinating activity of Bacteroides gingivalis 381 was significantly inhibited by the synthetic peptide, Asp-Ser-His-Ala-Lys-Arg-His-His-Gly-Tyr-Lys-Arg-Lys-Phe-His- Glu-Lys-His-His-Ser-His-Arg-Gly-Tyr. However, bradykinin potentiator C, which does not contain cationic amino acids such as L-histidine, L-arginine and L-lysine, had no inhibitory effect.

Amino Acid Sequence↗
PubMed1990

African swine fever virus: purification of capsomeres released by lipase.

The virus capsomeres of the outer and inner layers of capsids were effectively released simultaneously from purified virions by lipase digestion and were purified by a linear gradient ultracentrifugation. The capsid consisted of an array of double layers of uniformly arranged individual capsomeres where a lipid(s) served as a matrix in between the capsomeres.

African Swine Fever Virus↗
PubMed1990

Barrel rotation in rats induced by SMS 201-995: suppression by ceruletide.

Intracerebroventricular administration of SMS 201-995 (5 micrograms/rat), a somatostatin analogue, induced barrel rotation in rats. Pretreatment with ceruletide (40 micrograms/100 g b. wt., IP) 3 days or 7 days prior to the injection of SMS 201-995 significantly inhibited the response rate of barrel rotation induced by SMS 201-995, but not that induced by arginine-vasopressin (1 microgram/rat, ICV). The suppressive effect of ceruletide on barrel rotation could be partially countered by MK-329, a selective peripheral CCK (CCK-A) receptor antagonist. Desulfated cerulein did not affect the barrel rotation induced by SMS 201-995. These findings suggest that ceruletide specifically suppresses the barrel rotation evoked by SMS 201-995 in a long-lasting manner possibly acting through CCK-A receptor.

Amino Acid Sequence↗
PubMed1990

Purification and characterization from human parotid secretion of a peptide which inhibits hemagglutination of Bacteroides gingivalis 381.

A peptide from human parotid secretion which inhibited hemagglutination of Bacteroides gingivalis 381 was purified by ultrafiltration followed by DEAE-Sephadex A-25 column chromatography and by gel filtration on Sephadex G-25, and then by reversed-phase HPLC. The complete amino acid sequence of the peptide, determined by automated Edman degradation was as follows; Lys-Phe-His-Glu-Lys-His-His-Ser-His-Arg-Gly-Tyr. The peptide contained 12 residues and the charged amino acids predominated with 4 histidine, 2 lysine, 1 arginine and 1 glutamic acid residues, thus being a histidine-rich peptide. The peptide was an active inhibitor of the hemagglutinating activity of B. gingivalis. Specific binding of tritium-labeled peptide to B. gingivalis cells was demonstrated. These results suggest that the histidine-rich peptide may function as a binding domain for the hemagglutinins of B. gingivalis during agglutination.

Amino Acid Sequence↗
PubMed1990

Cytotoxicity of human eosinophil granule major basic protein to human nasal sinus mucosa in vitro.

The toxic effects of the human eosinophil granule major basic protein (MBP), reduced and alkylated, were studied on human nasal mucosa in vitro. With a microscope coupled with a television monitor (magnification x 2500) and videotape recorder, we investigated the effects of MBP on the mucosa and the ciliary activity of single cells. In nasal mucosal specimens from normal individuals, MBP, 5 mumol/L and 10 mumol/L, significantly inhibited (p less than 0.01) ciliary activity by 4 and 1 hours of exposure, respectively. At these same MBP concentrations, the mucosal surface profiles were altered by 4 hours of exposure, and ciliostasis was 75% to 100% complete by 9 and 6 hours, respectively. In a mucosal specimen from a patient with nasal allergy, 1 mumol/L of MBP significantly inhibited (p less than 0.01) ciliary activity by 1 hour; alteration of the mucosal surface profile appeared by 3 hours of exposure, and ciliostasis was 75% to 100% by 13 hours. Similar alterations of the mucosal surface profile were observed with specimens from a second patient with allergies; in contrast, 1 mumol/L of MPB had no effect on specimens from a nonallergic patient. These results indicate that MBP damages human upper respiratory epithelium, causing ciliostasis and alteration of the epithelial surface at concentrations likely achieved in vivo. Furthermore, the mucosal specimens from two allergic patients were damaged by concentrations of MBP that had no effect on mucosal specimens from a normal individual.

Blood Proteins↗