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Biomedical subjects

K Yasui

Publications and source records attributed to K Yasui.

At least 307 records · Page 17Linked to original sources
PubMed1987

Genetic characterization of JC virus Tokyo-1 strain, a variant oncogenic in rodents.

The genome DNA of JC virus Tokyo-1 strain [JCV(Tokyo-1)], a variant oncogenic in rodents, was molecularly cloned directly from the brain of a Japanese patient with progressive multifocal leukoencephalopathy and from tissue culture, and the restriction enzyme cleavage pattern and regulatory sequences were determined. The restriction pattern of the cloned JCV(Tokyo-1) DNA was different from those of JCVs previously reported in the United States and Germany. Also, the arrangement of the regulatory sequence was unique to this strain. Thus JCV(Tokyo-1) can be classified as a new subtype. The relationship between the restriction pattern and the regulatory sequence of JCV(Tokyo-1), and its characteristic oncogenicity, is discussed.

Animals↗
PubMed1987

Analysis of immunity to infection with Salmonella typhimurium in outbred mice. II. Isolation and immunogenicity of the protective non-O antigenic component from ribosomal vaccine.

The active component in crude ribosomal fraction (CRF) of Salmonella typhimurium, capable of inducing protective antibody, was partially purified by two series of chromatography (Sephadex G-150 and DEAE-Sepharose CL6B) after sodium dodecyl sulphate (SDS)-treated CRF was precipitated with ammonium sulphate. The major active component was eluted by 0.4-0.45 M NaCl from DEAE-Sepharose CL6B, and its molecular weight was 43,000 as determined by SDS-polyacrylamide gel electrophoresis. Immunization with the fraction containing 43,000 component alone did not always confer protection on CF1 mice, but its administration together with either the purified transfer RNA (tRNA) or Freund's complete adjuvant (FCA) was much more effective against infection with S. typhimurium. Antibody to the fraction containing 43,000 component was not only free in serum but also associated with peritoneal cells. Macrophages that had been exposed to the antibody had enhanced anti-bacterial activity. Western blot analysis showed that 43,000 component did not react to antiserum to lipopolysaccharide (LPS), but to antiserum to CRF. The antibody elicited by non-O antigenic component and the cell-mediated resistance stimulated by the adjuvant effect of RNA together confer effective protection on CF1 mice.

Animals↗
PubMed1987

Analysis of immunity to infection with Salmonella typhimurium in outbred mice. I. Requirement of the antibody to non-O antigen for protection in mice that are not protected by the RNA-rich vaccine.

Two outbred mouse strains, ddY and CF1, were tested for their ability to be protected against infection with Salmonella typhimurium by several types of salmonella vaccines. These strains have the same levels of innate susceptibility to S. typhimurium, and also have the same capacity to develop delayed-type hypersensitivity (DTH) to salmonella antigens. Both the crude ribosomal fraction (CRF) and live-cell vaccines conferred acquired resistance on both strains, characterized by greater responses of T cells to salmonella antigens. Mice of the ddY strain were also protected by the purified transfer RNA (tRNA) vaccine, which was free of O antigens, but CF1 mice were not, despite the presence of T-cell reactivity with salmonella antigens. Neither strain was protected by the phenol-water-extracted lipopolysaccharide (LPS). The tRNA-immunized CF1 mice were protected by transfer of antiserum to CRF, but not by transfer of anti-LPS antibody. This antiserum to CRF, however, did not transfer acquired resistance into non-immune mice of either strain. These observations suggest that CF1 mice may require an antibody to another non-O antigen existing in CRF to develop acquired resistance, and that stimulation of the defence system by tRNA may be essential to the development of acquired resistance in CF1 mice.

Animals↗
PubMed1987

Origin of the medulloblastoma experimentally induced by human polyomavirus JC.

The origin of the medulloblastoma induced by JC virus (JCV) in golden hamsters was investigated by the in situ hybridization method. After inoculation of JCV into newborn hamsters, a few migrating cells in the cerebellar molecular layer as well as several cells in the internal granular layer hybridized with an antisense mRNA probe of JCV T-antigen on the 10th day. The number of cells positive for this probe decreased on the 15th and 20th days. Moreover, an incipient medulloblastoma consisting of many cells positive for T-antigen mRNA was noticed in the cerebellar internal granular layer 30 days after inoculation. About 6 months post inoculation, 95% of the animals had succumbed to medulloblastoma. Therefore, the origin of the medulloblastoma seemed to be the cells in the cerebellar external granular layer that were infected by JCV, that migrated normally through the molecular layer to the internal granular layer, and that began to proliferate to become medulloblastoma. When 5-day-old hamsters were inoculated, a few cells positive for T-antigen mRNA were detected in the cerebellum within a month. In the long-term observation, the ratio of medulloblastoma induction decreased as the age of the animals at inoculation increased. These results support the idea that JCV infects and transforms the cells in the cerebellar external granular layer, because this layer appears only transiently in newborn hamsters.

Animals↗
PubMed1987

[Left ventricular asynergy in patients with impending myocardial infarction: two-dimensional echocardiographic assessment].

To determine the clinical significance of regional left ventricular asynergy in patients with impending myocardial infarction, we recorded two-dimensional echocardiograms (2DE) serially and performed coronary angiography immediately after the hospital admission in nine patients with initial impending infarction and their last anginal attacks were within 48 hours. Left ventricular asynergy on the first 2DE was observed in six of nine patients during symptom-free periods (Group A: LV asynergy group). Five of the six patients had significant coronary artery lesions (greater than or equal to 75% stenosis) in at least one major coronary artery. Intracoronary filling defects were detected in four of the five patients. Another three patients without asynergy (Group B) had significant fixed stenosis. Coronary artery spasm was observed in two patients during coronary angiography, but no patient had intracoronary filling defects. Intracoronary nitroglycerin (0.1-0.3 mg) reduced the severity of coronary artery narrowing in two patients. In addition, urokinase (240,000-480,000 IU) via the corresponding vessel (PTCR) in the remaining seven patients resulted in reduction in the severity of coronary artery stenosis in four patients, but not in the remaining three patients. Left ventricular wall movement in the asynergy group improved rapidly and no asynergy was observed by the seventh hospital day in five of the six patients. Successful PTCR treatment resulted in improvement of left ventricular wall movement. No asynergy was found in the non-asynergy group throughout their hospitalizations. These findings indicated that abnormal left ventricular wall movement is found in patients with impending myocardial infarction, even during symptom-free periods, but the wall movement gradually improves. The 2DE observations are useful for estimating the clinical status and for planning precise therapy for impending myocardial infarction.

Adult↗
PubMed1986

Nucleotide sequence at the 3' end of Japanese encephalitis virus genomic RNA.

Japanese encephalitis (JE) virus genomic RNAs were purified from virions. Two hundred nucleotides at the 3' end of JE virus genomic RNA were directly sequenced by using reverse transcriptase. The nucleotide sequence at the 3' end of the viral RNA was conserved among four kinds of JE virus strains. The sequence has no AU-rich region that is present at the 3' termini of alphavirus RNAs. We also compared the nucleotide sequences at the 3' ends of RNAs from three different flaviviruses and found several common sequence elements. A secondary structure at the 3' end of JE virus genomic RNA was proposed that may be common among flavivirus genomic RNAs. Such structures and other common stretches of nucleotide sequences may be related to the biological properties of flaviviruses.

Base Sequence↗
PubMed1986

Method for analyzing outlines with an application to recent Japanese crania.

If the visual image and quantitative treatment of a form could be merged, the combination could become a powerful analytical method in morphology. A method is presented for creating an averaged outline. In this method, since the averaged outline is produced statistically, hypothesis testing can be performed on the visual image of the outlines. Intra- and intergroup variation of the outlines can then be assessed by taking allometry into account. This method is applied to the analysis of sexual differences in the midsagittal outline of recent (1880s-1920s) Japanese crania. The averaged outlines of both sexes showed subtle features that could not be detected by traditional measuring techniques. Because the roundness, flatness, or protrusion of specific aspects of the morphology are clearly apparent, sexual differences in this sample could be identified. Changes resulting from allometry did not seem to be present in either sex. The shape distance (DIR) introduced here matched well the visual impression derived from comparisons of the Japanese sample with a Jomon (Neolithic) male and the Broken Hill specimen.

Cephalometry↗
PubMed1986

Paradoxical elevations of plasma glucagon levels in patients after pancreatectomy or gastrectomy.

In twenty-five patients undergoing total pancreatectomy (TP), twenty distal gastrectomy (DG) and twenty healthy subjects, effects of oral glucose loading on the plasma glucagon (IRG) levels were determined. Plasma IRG levels were elevated after glucose loading in the TP and DG patients, but not in the healthy subjects. To clarify events related to the elevations in IRG, the plasma IRG components were analyzed by gel filtration in 6 of the TP patients, 5 of the DG patients and 4 of the controls. In the TP group, IRG3500 was not detectable either in the basal state or after glucose loading, while IRG9000 was markedly increased after glucose (p less than 0.002). In the DG group, IRG3500 was significantly suppressed after glucose (p less than 0.05), but IRG9000 was clearly increased (p less than 0.005). In the controls, IRG3500 was suppressed after glucose (p less than 0.05), however, IRG9000 was not detected throughout the examination. Thus, in patients with TP or DG, the essential cause of the high responses of plasma glucagon after oral glucose loading was the increase in IRG9000. Because the food passage route is much the same in TP and DG patients, the IRG9000 elevations are probably related to secretion in the digestive tract.

Adult↗
PubMed1986

Antigenic comparison of envelope protein E between Japanese encephalitis virus and some other flaviviruses using monoclonal antibodies.

The antigenic relationships between Japanese encephalitis (JE) virus and several other flaviviruses have been investigated using anti-JE virus monoclonal antibodies (MAbs). Seventeen MAbs directed against envelope protein E of JE virus were characterized and divided into eight MAb groups based on reactivity patterns in haemagglutination inhibition test, neutralization (N) test, ELISA and competitive binding assay with JE virus. The results suggest the existence of at least eight epitopes on the E protein of JE viruses. Analysis of cross-reactivity of the antibodies with several other flaviviruses indicated these findings JE virus, belonging to West Nile (WN) subgroup, is antigenically closely related to viruses in the same subgroup, i.e. Murray Valley encephalitis (MVE), WN and St. Louis encephalitis (SLE) viruses. Of these three viruses, JE virus has the closest relationship with MVE virus. WN virus is relatively close to JE virus, whereas SLE virus is the least closely related. Dengue viruses types 1 and 2, which belong to another subgroup of flaviviruses, show markedly less antigenic homology to JE virus. One of the critical N sites on the E protein showed JE virus specificity. Some cross-reactive antibodies which did not neutralize JE virus showed low but significant N activity against several other flaviviruses. Mixtures of several MAbs, which showed different reactivity patterns, potentiated the N activity against not only JE virus but also other members of the WN subgroup of flaviviruses, namely MVE, WN and SLE viruses.

Antibodies, Monoclonal↗
PubMed1986

[A randomized controlled trial of surgical adjuvant therapy with mitomycin C, 5-fluorouracil and OK-432 in patients with gastric cancer].

The effect of postoperative immunochemotherapy with mitomycin C (MMC), 5-fluorouracil (5-FU) and OK-432 was evaluated as an adjuvant therapy after curative resection for gastric cancer. Immediately after surgery, patients were randomly allocated to the following three treatments: (A) chemotherapy with MMC and 5-FU (32 cases); (B) chemoimmunotherapy with MMC, 5-FU and OK-432 (33 cases); and (C) surgery alone as control (34 cases). There were no significant differences in the background factors influencing survival time among the groups, and there was no dose-distribution of chemotherapeutic agents between groups A and B. While the differences were not statistically significant, the survival rate and disease-free interval of group B were better than those of groups A or C. Side effects such as gastroenteric disorder, leukopenia (less than 3,000/mm3), thrombocytopenia (less than 7 X 10(4)/mm3) and increase of serum transaminase level (GPT greater than or equal to 100 units) were less frequently observed in group B than in group A. The results of the present study seemed to indicate that chemoimmunotherapy with OK-432 may be effective for surgical adjuvant therapy.

Aged↗
PubMed1986

Cellular aspects of the longer-lasting immunity against mouse typhoid infection afforded by the live-cell and ribosomal vaccines.

In order to compare the potential of salmonella vaccines prepared from Salmonella typhimurium to provide the longer-lasting protection from the aspects of cell-mediated immunity, groups of mice were immunized with optimal doses of the following preparations: live cells, ribosome-rich extract, acetone-killed cells, and heat-killed cells. At various intervals post-immunization, mouse peritoneal macrophages and splenic T cells were tested for biological activities. The capacity of each vaccine to confer mouse protection against a lethal challenge with S. typhimurium correlated with the degree of macrophage activation engendered by each of them in the early stage of immunization. In the late stage of immunization, the level of mouse protection conferred by each vaccine was found to be based on the capacity of T cells to respond to salmonella antigens, which correlated with the degree of adoptive immunity by T cells. The live-cell and ribosomal vaccines were superior to killed-cell vaccines in inducing the cell-mediated protection. Thus, the longer-lasting immunity provided by the live-cell and ribosomal vaccines can be accounted for by the fact that T cells of mice immunized with both vaccines have the persistent reactivity to salmonella antigens.

Animals↗
PubMed1985

A focus assay method for Japanese encephalitis virus using complement and anti-virus serum.

A sensitive, quantitative, short-time, and reproducible focus assay for Japanese encephalitis (JE) virus is described. After 2 or 3 days of incubation, the infected cells were treated with anti-JE virus serum and complement, and subsequently stained with trypan blue; then clear foci were produced. This method made it easy to titrate the infectivities not only of all seven JE virus strains tested but also of West Nile (WN), Murray Valley encephalitis (MVE), and St. Louis encephalitis (SLE) viruses using hyperimmune anti-JE virus serum for the latter. Moreover, even cell lines which hardly formed plaques by the agar overlay method easily produced foci within 2 or 3 days by this method.

Animals↗
PubMed1985

Leukaemia cell mobility in childhood acute myeloid leukaemia based on the FAB classification.

Leukaemia cell mobility was evaluated by the agarose plate method in 20 children with acute myeloid leukaemia (AML) based on the FAB classification. M1 blasts from 3 patients did not show any migration, probably reflecting their cellular immaturity. Leukaemia cells from 3 of 8 patients with M2 AML showed random migration, but those from the remaining 5 did not have this ability. The results thus demonstrated the heterogeneity of M2 AML in the function as well as the morphology. The M3 leukaemia cells failed to migrate under agarose in 2 patients studied, implying that a certain cytoskeletal defect in the cells. In all of 2 M4, 2 M5A and 3 M5B AML patients, leukaemia cells showed active mobility. The random migration value (mean +/- SD) of M5A and M5B cells was 5.7 +/- 1.7 compared with that of normal monocytes of 4.0 +/- 0.4 (p less than 0.01), indicating the enhanced random migration of leukaemia monocytes. M4 and M5B leukaemia cells had chemotactic responsiveness to zymosan-activated serum comparable to that of normal monocytes, but M5A cells were different from them in lacking apparent chemotactic responsiveness to the factor. Lymphadenopathy and leucocytosis were more prominent in the patients whose leukaemia cells were capable of migration than in those not having such cells. Mobility of leukaemia cells probably reflects their cell lineage, cellular maturity and functional distortion during leukaemic transformation, and appears to be related to clinical features.

Adolescent↗