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Biomedical subjects

M Hamaguchi

Publications and source records attributed to M Hamaguchi.

At least 199 records · Page 11Linked to original sources
PubMed1989

[Treatment with sulbactam/cefoperazone of severe infections in patients with hematological disorders].

Infectious episodes in 90 patients with hematological disorders were treated with sulbactam/cefoperazone (SBT/CPZ), a new combination drug of a potent beta-lactamase inhibitor, sodium sulbactam, and a third generation cephalosporin, sodium cefoperazone. Clinical responses to the SBT/CPZ regimen were excellent in 23 cases, good in 30 cases, fair in 11 cases, and poor in 26 cases. The overall efficacy rate (percentage of cases showing excellent or good responses) was 58.9%. Efficacy rates classified according to different infections were: 80% in documented sepsis, 57.6% in suspected sepsis, 61.1% in pneumonia and 50% in other infections. One episode of side effect was encountered with redness and itching of skin. Hepatic disorders were observed in 3 cases. These adverse reactions, however, were not serious. These results indicate that SBT/CPZ has a high therapeutic efficacy to severe infections in patients with hematological disorders.

Adolescent↗
PubMed1988

A novel viral oncogene with structural similarity to phospholipase C.

Numerous oncogenes have been isolated from acutely transforming retroviruses. To date, the products of these viral oncogenes have been protein kinases, nuclear proteins, growth factors, or GTP-binding proteins. We have cloned the previously uncharacterized avian sarcoma virus CT10 and sequenced its genome. This virus encodes a protein, p47gag-crk, that has blocks of sequence similarity to the amino-terminal, non-catalytic region of the non-receptor class of tyrosine kinases. In addition, the structure of p47gag-crk has striking similarity to a 180-amino acid region of bovine brain phospholipase C. Biochemical data suggest that p47gag-crk activates one or several endogenous tyrosine kinases.

Amino Acid Sequence↗
PubMed1988

Structural features unique to each of the three antigenic sites on the hemagglutinin-neuraminidase protein of Newcastle disease virus.

Antigenic variants of D26 strain of Newcastle disease virus (NDV) were selected with monoclonal antibodies directed to the three nonoverlapping antigenic sites on the hemagglutinin-neuraminidase (HN) protein, and their HN genes were sequenced to identify the amino acids important for the integrity of each site. Seven variants for site I, which is immunodominant and conserved among NDV strains, had a change of glutamic acid at position 347, mostly to lysine, and in a single case, to glycine. In the second group of two variants for site IV, a change of asparagine to aspartic acid was found at position 481. This resulted in elimination of the oligosaccharide attached to this asparagine residue of the parental virus. Together with the finding that the site IV was destroyed by treatment with endoglycosidase F, it was suggested that the oligosaccharide is important for maintaining the structure of site IV. The oligosaccharide appeared to contribute to exposing a nearby determinant by conferring hydrophilicity on it. A variant for site II had also a nonconservative mutation resulting in the change of glutamic acid to valine at position 495. The site I recognized by antibodies which inhibit neuraminidase activity with a small substrate neuraminlactose was located closer to the predicted sialic acid-binding site than to the other sites recognized by antibodies lacking the enzyme-inhibiting capacity. The sequence of the parental virus HN gene revealed that the HNo precursor for the HN protein is an extra-long protein whose C terminus is elongated by 45 amino acids, compared with the usual HN protein sequenced in parallel.

Amino Acid Sequence↗
PubMed1988

One liver for two: an experimental study in primates.

The need for liver grafts is critical in countries where brain death is not accepted as a legal criterion for organ retrieval. This experimental study was conducted with nonhuman primates in order to evaluate the feasibility of liver transplantation using a living donor. An original technique was employed to remove the left part of the liver from the donor: transection of the parenchyma was done while the blood flow was kept to the left part of the liver. In the recipients, the graft was placed heterotopically. No blood transfusions were administered to donors or recipients. In spite of a few failures, due to consequences of intraoperative bleeding, several donor operations using this original technique were successful, in the immediate postoperative period as well as several months later. Among the recipients, the large number of early failures suggests that the heterotopic position is probably not the appropriate one and that orthotopic transplantation should be preferred.

Animals↗
PubMed1988

Phosphorylation of cellular proteins in Rous sarcoma virus-infected cells: analysis by use of anti-phosphotyrosine antibodies.

The protein substrates for the tyrosine protein kinases in cells transformed by avian sarcoma viruses were analyzed by gel electrophoresis in combination with immunoblotting or immunoprecipitation by antibodies against phosphotyrosine. We found that greater than 90% of phosphotyrosine-containing cellular proteins can be immunoprecipitated by these antibodies. The level of phosphotyrosine-containing cellular proteins detectable by this method markedly increased upon transformation with Rous sarcoma virus, and more than 20 distinct bands of such proteins were found in lysates of Rous sarcoma virus-transformed cells. Most of these phosphotyrosine-containing proteins had not been identified by other methods, and their presence appeared to correlate with morphological transformation in cells infected with various Rous sarcoma virus mutants and Y73, PRCII, and Fujinami sarcoma viruses. However, considerably different patterns were obtained with cells infected with nontransforming Rous sarcoma virus mutants that encode nonmyristylated src kinases, indicating that most substrates that correlate with transformation can only be recognized by p60v-src associated with the plasma membrane.

Animals↗
PubMed1988

Carrier detection in Japanese hemophilia A by use of three intragenic and two extragenic factor VIII DNA probes: a study of 24 kindreds.

The three factor VIII intragenic restriction fragment length polymorphisms (RFLPs), Bcll, Xbal, and Bgll and the two extragenic RFLPs, Bglll/DX13 and Taql/St14, were analyzed in 60 normal Japanese subjects and 24 families with hemophilia A. The allele frequencies were determined and the extent of linkage disequilibrium among the polymorphisms was assessed. In contrast to intragenic RFLPs of the factor IX gene, intragenic and extragenic RFLPs of the factor VIII gene in Japanese were similar to those observed in whites. As in whites, marked linkage disequilibrium severely compromised the value of the Bgll RFLP. The combination of the Bcll, Xbal, and Taql/St14 RFLPs gave 100% carrier detection in the hemophilia A families analyzed.

Asian People↗
PubMed1987

Detection of polycistronic transcripts in Newcastle disease virus infected cells and identification of their sequence content.

The synthesis of six to seven polycistronic transcripts of Newcastle disease virus (NDV) in BHK cells was detected by Northern hybridization using cDNA clones generated by reverse transcription of five NDV mRNAs. Within the molecular weight range resolved by the gel electrophoresis system employed, four of the transcripts were suggested to be distronic, containing sequences of two genes, NP-P, P-M, M-F0 and F0-HN, respectively. In addition, tricistronic molecules of M-F0-HN and possibly of NP-P-M as well as P-M-F0 appeared to develop, although they were very low in amount. These data suggest a gene order of NP-P-M-F0-HN on the NDV genome. The polycistronic as well as monocistronic transcripts were generated with an almost constant proportion in amount throughout the virus replication. Further, at least several of them were also generated under the conditions where only the primary transcription was allowed by inhibiting de novo protein synthesis. Therefore, it appears likely that there is no distinct temporal control in NDV genome expression.

Amino Acid Sequence↗
PubMed1987

Structural comparison of the cleavage-activation site of the fusion glycoprotein between virulent and avirulent strains of Newcastle disease virus.

The nucleotide sequence of the mRNA encoding the fusion (F0) protein of a virulent strain of Newcastle disease virus was determined. A single open reading frame in the sequence encodes a protein of 553 amino acids with a calculated molecular weight of 59058. The amino acid sequence predicted several structural features involving the fusion-inducing hydrophobic stretch (residues 117-142) and the cleavage-activation site (residues 112-116) to generate the disulfide-linked F1 and F2 subunits. The cleavage-activation site as well as a part of the fusion-inducing sequence were compared among a series of virulent and avirulent strains by the chain-termination method using a synthetic oligonucleotide primer. It was found that without exception, the cleavage-activation site of virulent strains consisted of two dibasic residues with an intervening glutamine, Arg-Arg-Gln-Arg-Arg, whereas the corresponding region of avirulent strains was made of a sequence with single basic residues scattered among uncharged residues, Gly-LysArg-Gln-GlySer-Arg. On the basis of these observations and the previous results showing a strict correlation between the pathogenicity and the cleavability of the fusion protein of NDV (Y. Nagai, H-D. Klenk, and R. Rott, Virology, 72, 494-508, 1976), we propose the importance of the dibasic residues for efficient proteolytic activation of the fusion protein and for the pantropic property of NDV. Some strains were found to have Leu-Ile-Gly as the N-terminus of F1, whereas others contained Phe-Ile-Gly, indicating that Phe-X-Gly is not always conserved at F1 N-terminus of paramyxovirus.

Amino Acid Sequence↗
PubMed1987

Antigenic characterization of the internal proteins of Newcastle disease virus by monoclonal antibodies.

We have prepared and characterized monoclonal antibodies against the three internal structural proteins, M, P and NP, of Newcastle disease virus. At least two non-overlapping antigenic sites were delineated on the M protein, four on the P, and two on the NP by competitive binding assay. One of the two non-overlapping antigenic sites on the M protein was found to be a cluster of at least three distinct epitopes. Enhancement of antibody binding by the binding of a second antibody was observed with the M protein. The reactivity of these monoclonal antibodies with heterologous strains was studied by enzyme-linked immunosorbent assay. The results indicated that there are both highly conserved antigenic sites and those subject to remarkable change on both M and P proteins. On the other hand, NP appeared to be antigenically more stable.

Antibodies, Monoclonal↗
PubMed1987

Abdominal aortic aneurysm complicated with chronic disseminated intravascular coagulopathy: a case of surgical treatment.

This article reports a case of an infrarenal abdominal aortic aneurysm complicated with chronic disseminated intravascular coagulopathy (DIC). The patient was a 68-year-old man; bleeding of 20 months' duration was reported. Physical examination indicated a pulsating mass in the abdomen. The diagnosis of DIC was made on the basis of standard coagulation studies. Indium 111-labeled platelet scintigraphy demonstrated an increased accumulation of radioactivity over the aneurysm. After preoperative control of the bleeding tendency was obtained by continuous intravenous infusion of gabexate mesilate (FOY), the aneurysm was successfully replaced with a prosthetic graft. Gabexate mesilate therapy is useful for DIC as is heparin therapy. If surgical intervention is required for an abdominal aortic aneurysm with concomitant DIC, preoperative control of bleeding with gabexate mesilate or heparin is recommended to lessen operative bleeding.

Aged↗
PubMed1987

Association of p60src with Triton X-100-resistant cellular structure correlates with morphological transformation.

More than 70% of wild-type Rous sarcoma virus p60v-src was found to be associated with a cellular structure resistant to nonionic detergent extraction that consists primarily of cytoskeletal proteins. On the other hand, nontransforming src proteins, including cellular p60c-src, nonmyristoylated forms, and those inactive in protein kinase, were found in the fraction solubilized by the detergent extraction. p60c-src was detergent-soluble even in transformed cells, suggesting that the association of p60v-src is not a result of cell transformation. Analyses with a variety of Rous sarcoma virus mutants showed a good correlation between the degree of association with the detergent-resistant structure and the extent of cell transformation caused by mutant src proteins, suggesting that this association may be significant for the process of cell transformation by Rous sarcoma virus.

Animals↗
PubMed1986

Studies on the adaptation of mumps virus to chick embryo.

About 15 serial passages of wild type mumps virus (Sasazaki strain) in the amnion sac of chick embryo (CE) yielded a CE-adapted strain which was poorly replicative and did not form plaques in Vero cells where the wild strain grew well. In the course of this limited replication of the CE-adapted strain in Vero cells, we have analysed the viral protein and RNA synthesis. It was found that protein synthesis took place very efficiently at least early in infection by 12 h. The subsequent rate of synthesis remained, however, at a low level without showing the progressively increasing synthesis observed with the wild strain. Furthermore, 50S genomic RNA was synthesized early in the limited infection, but the subsequent synthesis was markedly suppressed. In addition, the other virus-specific RNA species could not be detected throughout. Thus the amplified RNA synthesis observed in the permissive CE cells and in the wild strain-infection of Vero cells seemed not to occur in the limited replication. Neither interferon nor DI (defective interfering) RNA was involved in the limited virus growth. When Vero cells were infected with the wild strain 6 to 8 h before inoculation of CE-adapted strain, growth restriction was overcome and the yield of the latter virus was greatly enhanced by a factor more than 10(3). These results suggest that through adaptation to CE, mumps virus may be altered in such a way that there is a restriction, probably at a step (s) involved in amplification of the viral RNA synthesis in Vero cells and that the restriction may be overcome by the simultaneous genome expression of the prototype wild strain.

Animals↗
PubMed1986

Inhibition of the assembly of Newcastle disease virus by monensin.

Monensin inhibits the intracellular transport of the glycoproteins of Newcastle disease virus between cis and trans Golgi stacks of infected BHK cells, as evidenced by its effect upon their post-translational modifications such as fatty acid acylation, glycosylation and proteolytic cleavage. Thus the drug has markedly altered the subcellular distribution of the glycoproteins so that they accumulate in the internal smooth membranes but are virtually absent in the plasma membrane. These glycoproteins that accumulated in intracellular membranes have a cytoplasmic domain susceptible to protease digestion and thus are transmembranous. Under such conditions, the behavior of M protein, which plays a crucial role in virus assembly (Y. Nagai et al., 1976, Virology 69, 523-538), has been analyzed. It has been found that the M protein can neither associate with the internal membranes nor bind to the plasma membrane. Thus no virus budding has been observed, either at the plasma membranes or at internal membranes. These results substantiate the view that the interaction between M and glycoproteins is of great importance for virus assembly and suggest further that this interaction is possibly only when the glycoproteins have been incorporated into the plasma membrane.

Animals↗