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Biomedical subjects

Y Iwamura

Publications and source records attributed to Y Iwamura.

At least 55 records · Page 3Linked to original sources
PubMed1991

Deletions and rearrangements of the retinoblastoma gene in hepatocellular carcinoma, insulinoma and some neurogenic tumors as found in a study of 121 tumors.

The retinoblastoma gene (Rb) is one of the tumor suppressor genes to have already been cloned. Deletions and inactivations of the gene have been widely observed in various types of human tumor. To study the generality of Rb alteration in human tumors, 121 cases of tumor DNAs were examined for abnormalities in the gene structure by blot hybridization. Deletions of both alleles were detected in hepatocellular carcinoma, insulinoma and neuroblastoma. Rearrangements and allelic deletions of the Rb gene were, moreover, observed in some brain tumors and hepatocellular carcinomas, respectively. All were surgically resected tumors. The observations suggest the inactivation of Rb through structural alterations sometimes to correlated with the development or progression of these types of human tumor.

Blotting, Southern↗
PubMed1990

Dynamic changes of DNA sequences in Schistosoma mansoni in the course of development.

Deletion and/or amplification of DNA sequences in Schistosoma mansoni were demonstrated by Southern blot analysis. Total cellular DNAs and genomic clones derived from S. mansoni miracidia, adult males and females were used as probes. Endonuclease BamHI-restricted DNAs from miracidia, adult males and females of both S. mansoni and S. japonicum were reacted to each probe. Hybridization with a total cellular DNA from S. mansoni miracidia as a probe showed elimination of signals in S. mansoni adults. On the other hand, blot analysis using a total cellular DNA from S. mansoni adult males as a probe revealed elimination of hybridization signals in S. mansoni miracidia. Hybridization with a clone SmE15 DNA from S. mansoni miracidia as a probe showed no signal in the DNAs from S. mansoni adults, indicating these sequences deleted in adults. Hybridization experiments using the probes SmF25 and SmM51 which are 1.3 and 2.2 kb fragments cloned from S. mansoni adult females and males respectively, demonstrated no signal to DNA from S. mansoni miracidia. Our data suggested the existence of stage-specific DNA sequences in S. mansoni. We propose a model for multiple-step rearrangement of DNA sequences in S. mansoni during the course of development.

Animals↗
PubMed1990

[Treatment of fulminant hepatitis with highly reliable artificial liver support and administration of interferon].

We treated 10 patients with viral fulminant hepatitis (FH) and subacute hepatitis (SH) by highly reliable artificial liver support (ALS), the combination of plasma exchange (PE) and hemodiafiltration (HDF) using polymethyl methacrylate (PMMA) membrane. All patients regained clear consciousness by the ALS. Even the patients with long term hepatic failure up to for 108 days were sustained in a favorable clinical condition. Five patients finally survived. Interferon was administered to one case with type B FH with positive HBeAg, four cases with NANB FH and SH who were assumed to have persistent viral replication. Two of them showed favorable clinical responses and definite liver regeneration was confirmed. The intensive liver support which can sustain patient with severe fulminant hepatic failure accompanied by the administration interferon is believed to be the most effective treatment for FH and SH especially caused by NANB virus in our country.

Acute Disease↗
PubMed1989

Integration and expression of murine retrovirus-related sequences in schistosomes.

Antibodies against the retrovirus envelope glycoprotein (gp70) of mouse xenotropic retrovirus, BALB virus 2 (Bv2) reacted with the adult worms of Schistosoma japonicum and S. mansoni. This reaction was completely inhibited after adsorption of the antibodies with virions of retrovirus. The reactive schistosome antigen was located in the subtegumental layer of the adult male fluke and in the vitelline gland of the adult female of S. japonicum and S. mansoni. Proteins extracted from both parasites were examined by immunoblot analysis. Anti-Bv2 gp70 antiserum reacted with those proteins from both schistosomes and the band patterns were different among sexes and species. Southern hybridization of the DNA extracted from adults of S. japonicum and S. mansoni demonstrated the presence of sequences homologous to the env gene of mouse ecotropic and xenotropic retroviruses. DNA sequences homologous to the gag and pol regions of the ecotropic murine leukaemia virus were also detected in the DNAs of schistosomes.

Animals↗
PubMed1989

Coamplification of the L-myc and N-myc oncogenes in a neuroblastoma cell line.

The L-myc, N-myc and c-myc genes are members of the myc oncogene family. In particular, L-myc is novel, and amplification of L-myc is still unknown except in small cell lung carcinoma. We examined L-myc amplification in 30 human neuroblastomas using Southern blot hybridization, and found that the L-myc gene was amplified approximately 5-fold in GOTO, a human neuroblastoma cell line. The N-myc gene was also amplified approximately 60-fold and furthermore, over-expression of L-myc and N-myc genes was observed in this cell line. In this report, we describe the coamplification of the myc gene family in the GOTO neuroblastoma cell line.

Blotting, Southern↗
PubMed1988

Synergistic interactions of interleukin 1, interferon-beta, and tumor necrosis factor in terminally differentiating a mouse myeloid leukemic cell line (M1). Evidence that interferon-beta is an autocrine differentiating factor.

The effect was investigated of combinations of cytokines known to be cytostatic for some tumor cells, namely interleukin 1 alpha (IL-1 alpha), interferon-beta (IFN-beta), and tumor necrosis factor (TNF), on the growth and differentiation of the mouse myeloid leukemic cell line, M1, cells. IL-1 alpha, IFN-beta, and TNF by themselves are antiproliferative for M1 cells. Treatment of cells with a mixture of any two of the three cytokines resulted in at least additive growth inhibition. None of these cytokines by themselves induced differentiation of M1 cells as assessed by increased expression of Fc receptors (FcR), stimulation of phagocytic activity and by morphologic criteria. However, as little as 1 U/ml IL-1 alpha in conjunction with IFN-beta or TNF increased FcR expression, phagocytic activity and morphologic changes in addition to inhibiting the growth of M1 cells. The combination of IFN-beta and TNF did not induce differentiation, although the growth of the cells was markedly inhibited. Both TNF and lipopolysaccharide (LPS) induced the in vitro production of IFN activity by M1 cells. Furthermore, the induction of differentiation of M1 cells by a combination of IL-1 alpha with either IFN-beta, TNF, or LPS was inhibited by antibody against mouse IFN-beta. Therefore, it appears that IFN-beta provides one of the two required signals for differentiation of M1 cells by these combinations of stimulants, the other being IL-1. Furthermore, the cytostatic effect of TNF by itself on M1 cells was also partly blocked by anti-IFN-beta antibody, suggesting that IFN-beta is also involved in the growth inhibitory effect of TNF for M1 cells. In contrast, the cytostatic effect of IL-1 on M1 cells was not blocked by anti-IFN-beta antibody. In conclusion, both the cytostatic and differentiative effect of TNF appear to be mediated by IFN-beta. Thus, the combination of IL-1 and IFN-beta or inducers of IFN-beta resulted in terminal differentiation of M1 cells. Northern blot analysis using cDNAs for murine IFN-beta1 or human IFN-beta2 showed an increased expression of mRNA for IFN-beta1 but not for IFN-beta2 by stimulation with TNF or LPS, strongly suggesting that IFN-beta 1 rather than IFN-beta 2 is responsible for TNF or LPS effects.

Animals↗
PubMed1988

TaqI polymorphism in the LDL receptor gene and a TaqI 1.5-kb band associated with familial hypercholesterolemia.

The low density lipoprotein (LDL) receptor gene was analyzed in 67 unrelated healthy Japanese and 38 members of six consecutive families with familial hypercholesterolemia (FH) by Southern blot hybridization with TaqI, an LDL receptor cDNA fragment containing exons 1 to 8 being used as a probe. A new TaqI RFLP at the LDL receptor locus was detected with allele frequencies of 0.67 and 0.33. The data obtained with smaller cDNA subfragment probes revealed that the TaqI RFLP site is located within 1.1 kb of the 5' side of the EcoRI site of exon 5. The TaqI RFLP was in linkage disequilibrium with the PstI RFLP but showed no significant linkage disequilibrium with the RFLPs for AvaII, ApaLI/I15, PvuII, NcoI, and ApaLI/3'. Among the seven RFLPs at the LDL receptor locus, the TaqI RFLP was the only useful genetic marker in one of the six families with FH. Furthermore, the association of an additional TaqI 1.5-kb band with a mutant LDL receptor gene was observed in another family with FH in which the proband was homozygous for all of the seven RFLPs. The data obtained with various restriction enzymes and smaller cDNA subfragments probes suggested that a minor change in nucleotide sequences in the region including exons 5 to 8 is present in the mutant gene. These data suggest that the TaqI RFLP is a useful genetic marker at the LDL receptor locus and that TaqI serves for the analysis of some mutant LDL receptor genes, when used with small LDL receptor cDNA probes.

DNA Restriction Enzymes↗
PubMed1986

Transforming potential of DNA of the human PLC/PRF/5 hepatoma cell line.

DNA of the human PLC/PRF/5 hepatoma cell line can induce the appearance of colonies on soft agar after transfection of BK-BK cells (BALB/c mouse kidney cells partially transformed by BK virus). Blot hybridization analyses indicate that the transformants contained the hepatitis B virus DNA sequence. This sequence disappeared during serial passage of transformants. The amplification and rearrangement of the integrated BK virus genome appears to be specifically associated with transformation.

Animals↗
PubMed1985

Deficits in manipulative behaviors induced by local injections of muscimol in the first somatosensory cortex of the conscious monkey.

Injection of muscimol (GABA agonist) in the finger region of area 2 of the alert monkey led to the striking yet reversible loss of finger coordination, thus disabling the monkey from picking up a small piece of food from a small hole or a funnel. Symptoms varied depending on sites of injection within the finger region. Neither weakness of hand or finger movements nor deficit in hand reach was observed.

Animals↗