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Biomedical subjects

M Hatanaka

Publications and source records attributed to M Hatanaka.

At least 253 records · Page 14Linked to original sources
PubMed1988

Processing of gag precursor polyprotein of human T-cell leukemia virus type I by virus-encoded protease.

The biological activity encoded in the putative protease gene (pro) of human T-cell leukemia virus type I was investigated by using a vaccinia virus expression vector. The 53-kilodalton gag precursor polyprotein was processed into the mature p19, p24, and p15 gag proteins when the gag and protease-coding sequence was expressed under the control of a vaccinia virus promoter, suggesting that the protease may be synthesized through the mechanism of ribosomal frame shifting. The processing defect of a protease mutant could be complemented by cointroduction of a wild-type construct into the cell, demonstrating that the pro gene encodes the biologically active protease molecules which are capable of processing the gag precursor polyprotein in vivo in trans. A study involving the use of a variety of mutants constructed in vitro revealed that the protease consists of a nonessential carboxy-terminal region and a part essential for its activity, including the putative catalytic residue, aspartic acid. Furthermore, a cluster of adenine residues positioned at the overlapping region between the gag and pro genes was shown to be involved in the ribosomal frameshifting event for the synthesis of protease. To mimic the formation of the 76-kilodalton gag-pro precursor polyprotein formed by ribosomal slipping, the coding frames of the gag and pro gene were adjusted. The processing of the gag-pro precursor polyprotein depended on an intact protease gene, implying that a cis-acting function of human T-cell leukemia virus type I protease may be necessary to trigger the initial cleavage event that leads to the release of protease from the precursor protein.

Amino Acid Sequence↗
PubMed1988

Effects and virulences of recombinant vaccinia viruses derived from attenuated strains that express the human T-cell leukemia virus type I envelope gene.

We constructed recombinant vaccinia viruses (RVVs) that expressed human T-cell leukemia virus type I (HTLV-I) envelope glycoproteins by using attenuated vaccinia viruses (VVs) which have much lower neurovirulence than the WR strain that is extensively used as a vector. The RVV produced from the LC16mO strain, one of the attenuated VVs, elicited a high titer of anti-HTLV-I antibody in rabbits and protected them against HTLV-I infection. The env gene was inserted into the VV hemagglutinin gene. The resultant inactivation of the hemagglutinin gene led to the attenuation of VVs, but the extent of their attenuation depended on the VV strain. The propagation of LC16mO and its RVV in rabbit brain was poorer than that of LO-1, a cloned derivative of Lister strain, and its RVV, although LC16mO replicated in other organs better than did LO-1. Taken together, these results suggest that LC16mO is a good candidate as a vector for vaccination of humans.

Animals↗
PubMed1988

Phenotypic conversion of T lymphoblastic lymphoma to acute biphenotypic leukemia composed of lymphoblasts and myeloblasts. Molecular genetic evidence of the same clonal origin.

Acute biphenotypic leukemia composed of lymphoblasts and myeloblasts developed in a patient with T lymphoblastic lymphoma (T-LBL) who had an anterior mediastinal mass. A novel myeloid cell line, termed TK-1, has been established from his peripheral blood after the leukemic conversion. The identical rearranged pattern of T cell receptor gamma-chain gene was observed among the DNAs derived from lymph node cells in the lymphoma phase, the myeloid cell line TK-1, and the subclones with different karyotypes (TK-1B and TK-1D), which showed that myeloid cells had been derived from the T-LBL of the same patient. This finding demonstrates that phenotypic conversion occurs in the clonally propagating tumor cells and suggests that some hematopoietic cells retain the capacity to adopt either lineage.

Acute Disease↗
PubMed1988

Distribution and expression of calpastatin in human hematopoietic system cells.

Thirteen cell lines of the human hematopoietic system were tested for expression of calpastatin at three different levels (mRNA, product and activity). The amount of calpastatin product and its inhibitory activity varied markedly depending upon cell types or human T-cell leukemia virus type I infection, although there were difference in the expression at the transcriptional level. Cell lines with high content of calpastatin comprised T-cell lineage infected by human T-cell leukemia virus type I, B-cell line and myelocytic leukemia cell lines. Non-infected T-cell lines and null cell line revealed themselves as poor in both calpastatin products and inhibitor activities. Two different molecular forms of calpastatin were observed: a 102-kDa form in T- and B-cell lines and a 94-kDa form in one of myelocytic cells. Three mRNA species of calpastatin (3.8, 3.0 and 2.5 kb) were identified in human hematopoietic system cells.

Calcium-Binding Proteins↗
PubMed1988

Endoscopic diagnosis of lymphangioma of the small intestine.

In three patients with lymphangioma of the small intestine, the preoperative diagnosis of lymphangioma was made by endoscopy with biopsy and radiology. A typical endoscopic finding was an elevated polypoid tumor, yellowish-white to tan. The surface was smooth, often with white specks, and could be impressed by touching lightly with biopsy forceps. Endoscopic examination revealed satellite lesions not detected radiologically. Lymphangioma has heretofore been successfully diagnosed preoperatively by endoscopy in the duodenum. This report of accurate preoperative diagnoses of lymphangioma in the small intestine, other than the duodenum, using endoscopy, may be the first to be documented.

Aged↗
PubMed1988

Ultrasonic real time guidance for subclavian venipuncture.

To minimize the complications arising from the subclavian venipuncture, ultrasonically (2-D Doppler) guided puncture was tried upon ten patients. Venipuncture was successful in nine patients whose subclavian vein was visualized by 2-D Doppler. In one patient, the subclavian vein had shifted cephalad, so the subclavian venipuncture was abandoned. Ultrasonically guided venipuncture is thought to be safer and a more sure method for subclavian venipuncture.

Catheterization, Central Venous↗
PubMed1987

All four internally repetitive domains of pig calpastatin possess inhibitory activities against calpains I and II.

Complementary DNA portions coding for each domain (domain L and internally repetitive domains, domains 1-4, each composed of approximately 140 amino acid residues) of pig calpastatin were subcloned into E. coli plasmids to express the respective portions of the proteinase inhibitor gene in bacteria. Cell extracts of E. coli harboring recombinant plasmids were assayed for calpain inhibition. All four internally repetitive domains showed inhibitory activities, essentially similar to one another, against calpains I and II. No inhibition was observed in the case of the N-terminal non-homologous domain (domain L). These results support our previous conclusion that the repetitive region is a functional unit of the proteinase inhibitor.

Amino Acid Sequence↗
PubMed1987

Expression of the c-myc gene in human gastrointestinal malignancies.

We have examined the level of the c-myc transcript in 6 esophageal, 16 gastric, 19 colorectal and 1 anal cancer tissue samples; these included four lymph nodes and six hepatic metastases obtained surgically. The esophageal cancer tissues were without an increase of the c-myc transcript, some of the gastric cancer samples showed a two to three fold increase and most of the colorectal and the one anal cancer samples showed a two to ten fold increase when compared with a normal mucosal layer. Therefore, the level of the c-myc transcript in human gastrointestinal malignancies shows organ dependency. Local, lymphatic, and hepatic metastases showed little difference in the level of c-myc mRNA from that of the primary tumor.

Actins↗
PubMed1987

Effect of actinomycin D on DNA replication and c-myc expression during rat liver regeneration.

In an attempt to elucidate the mechanisms that control the hepatic DNA replication, effect of low doses of actinomycin D on DNA synthesis and c-myc expression during the early stage of liver regeneration was investigated. Small amounts of actinomycin D, in amounts that had no effect on the rate of RNA synthesis in normal rats, were multiple injected at 0, 2 and 4 hours after partial hepatectomy. DNA synthesis and c-myc expression in these rats were compared with those in untreated rats. Hepatic DNA synthesis in the treated rats was delayed about 4 to 6 hours in comparison with control rats. In contrast, time course of c-myc expression in inhibitor treated rats was very similar to that in control rats.

Animals↗
PubMed1987

Repetitive region of calpastatin is a functional unit of the proteinase inhibitor.

A cDNA portion coding for one of the repetitive regions of pig heart calpastatin (107 kDa) was subcloned into E. coli plasmid pUC119 to express the portion of the proteinase inhibitor gene in bacteria. The expressed protein was a chimaeric protein whose calpastatin segment (130 amino acid residues) was fused with an amino-terminus portion (7 amino acid residues) of beta-galactosidase. The chimaeric protein could inhibit proteolytic activity of calpain (Ca2+-dependent cysteine proteinase), and maintained properties of the authentic calpastatin concerning inhibition specificity and heat stability. These findings led us to conclude that the repetitive region is a functional unit of the proteinase inhibitor.

Amino Acid Sequence↗
PubMed1987

Immunoglobulin heavy chain gene diversification in the long-term bone marrow culture of normal mice and mice with severe combined immunodeficiency.

The change of immunoglobulin heavy (H) chain gene configuration during the differentiation of B cells from their early precursors was investigated in long-term cultures of bone marrow cells (LTBC). Hemopoietic stem cells are maintained in LTBC described by Dexter et al. (J. Cell. Physiol. 1977. 91: 335; LTBC-D), which supports the differentiation of myeloid lineage cells but not B lineage cells. By simply shifting the culture condition to that devised by Whitlock and Witte (Proc. Natl. Acad. Sci. USA 1982. 79: 3608; LTBC-B) to support the development of B lineage cells, surface IgM-bearing (sIgM+) B cells became detectable by the 2nd week after the shift and the number quickly increased thereafter, while the number of polymorphonuclear cells and granulocyte-macrophage colony-forming cell (CFU-c) decreased rapidly. H chain gene configuration of the developing cells in the culture was examined by Southern blot analysis of Eco RI-digested DNA with a JH probe. Whereas rearranged JH gene configuration was not detectable in the DNA from LTBC-D cells, it first appeared 2 weeks after the shift, and the level of the rearrangement rapidly increased thereafter as the intensity of JH band of germ-line configuration decreased. Almost all the cells in the culture had undergone H chain gene rearrangement in both chromosomes by the 6th week after the shift. During 2 to 4 weeks after the shift, a cluster of bands spanning around 4.5-5.5 kb appeared dominant among the rearranged configurations of JH gene and then it decreased in intensity as the pattern of JH band became a more homogeneous smear. The distribution of rearranged JH bands observed during 3-4 weeks after the shift was strikingly similar to that observed in normal spleen B cells. By semi-quantitative analysis of the intensity of JH and DSP2 bands remaining in germ-line configuration, it was found that the loss of germ-line JH band was far more rapid than that of germ-line DSP2 bands in the developing B cells in vitro. This result is consistent with the conclusion obtained in B cell tumor lines that D to J assembly occurred first and was followed by V to DJ assembly in this culture system. Taken together, it is likely that the process of H chain gene diversification in this culture system may represent the actual process during B cell differentiation in vivo. Differentiative capacity of bone marrow stem cells from mouse with severe combined immunodeficiency (SCID) was also analyzed in the same culture system.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Effect of the recombinant vaccinia viruses that express HTLV-I envelope gene on HTLV-I infection.

The human T-lymphotropic virus type I (HTLV-I) is etiologically linked to adult T-cell leukemia (ATL). To develop a vaccine against ATL, we constructed recombinant vaccinia viruses containing the envelope gene of HTLV-I in the vaccinia virus hemagglutinin (HA) gene, a new site where foreign genes can be inserted. A single inoculation of the recombinant virus induced antibodies to the env proteins of HTLV-I in rabbits and had a protective effect against HTLV-I infection.

Animals↗
PubMed1987

2-Mercaptoethanol acts at the restricted stage of interleukin-2 dependent lymphocyte proliferation.

An interleukin-2 (IL-2) dependent murine cell line (TN-9) which could be grown continuously with the crude culture supernatant of concanavaline A-stimulated rat or mouse spleen cells could not synthesize DNA in the culture medium supplemented with partially purified or recombinant IL-2. The cell growth was restored by adding another factor obtained from the same crude culture supernatant. This factor, physicochemically inseparable from serum albumin, was also obtained from the culture medium added with 2-mercaptoethanol (2-ME) and incubated at 37 degrees C for 24 hr without the cells. By the experiments using semi-synchronized cell population, it was demonstrated that 2-ME or 2-ME carrying protein acted at the restricted process(es) of cell proliferation which occurred between IL-2-acting stage and the initiation of DNA synthesis.

Animals↗
PubMed1987

Reciprocal effects of epidermal growth factor and transforming growth factor beta on the anchorage-dependent and -independent growth of A431 epidermoid carcinoma cells.

The effects of epidermal growth factor (EGF) and transforming growth factor beta (TGF beta) on the growth of A431 epidermoid carcinoma cells were studied. Whereas the monolayer growth of A431 cells was inhibited by EGF, it was stimulated by TGF beta. Contrary to the effects on the monolayer growth, EGF stimulated the soft agar growth of A431 cells. The stimulatory effects of TGF beta on the anchorage-dependent growth were antagonized by EGF and those of EGF on anchorage-independent growth were antagonized by TGF beta. These results suggest that both factors not only convey the proliferative signals to A431 cells but also induce phenotypic changes, resulting in a preference for either anchorage-dependent or anchorage-independent growth. Moreover, as the stimulatory effects of EGF on the soft agar growth of A431 cells paralleled its reported stimulatory effects on their in vivo growth, it is also suggested that in vivo responses of cells to certain growth factors may correlate better with their responses in soft agar culture than with those in monolayer culture.

Agar↗
PubMed1987

Quantitative analysis of cytotoxicity induced by HTLV-I carrying cells against a human lymphoblastoid cell line, Molt-4.

Co-cultivation of HTLV-I carrying cells and virus-free lymphoid cells resulted in the cytopathic effect and cytotoxicity of the latter cells. Microscopically, these phenomena were observed as early as 2 h as the appearance of multinuclear giant cells and ballooning cells with striking resemblance with cytopathic changes induced by HTLV-III. When the cytopathic effect and cytotoxicity of the target cells by HTLV-I carrying cells were assayed by 51Cr-release assay system, these phenomena were quantitatively analysed and the cytotoxic activity was observed generally in HTLV-I positive cells. Virally induced cytotoxicity was inhibited by plasma of adult T-cell leukemia (ATL) patients specifically. Cytotoxic activity of HTLV-I positive cell lines was correlated with HTLV-I antigen expression of them. HTLV-I negative cell lines did not express cytotoxicity significantly.

Cell Line↗
PubMed1987

Construction of a new plasmid vector that can express cloned cDNA in all translational reading frames.

Construction of a bacterial expression vector, pSI4001, is described. The vector contains the lac promoter-operator and three sets of ribosome-binding sites (RBSs) tandemly arranged in all possible reading frames. cDNA can be directly cloned downstream from these translational start points in the fixed and proper orientation by using the method of Okayama and Berg [Mol. Cell. Biol. 3 (1982) 280-289]. The open reading frame of any cDNA inserted may be automatically aligned in phase with either of the three ATG start codons, thus enabling its expression with a maximum theoretical probability of unity. Fusion with the lacZ gene (coding for beta-galactosidase) has shown that at least two of the three translation initiation sites exhibit high expression capacities and the remaining one can also function at a lower but significant rate. We used the vector to construct a bovine pituitary cDNA library, from which clones coding for prolactin were detected by immunological screening with an efficiency as high as two in three clones. The construction with triple RBSs should also provide a unique experimental model to study the regulation of overlapping translations.

Animals↗
PubMed1987

Expression of a provirus of human T cell leukaemia virus type I by DNA transfection.

We isolated the full length provirus of human T cell leukaemia virus type I (HTLV-I) from MT-2, a lymphoid cell line producing HTLV-I. In three non-lymphoid cell lines (COS7, human osteosarcoma HOS cells, and HeLa) this provirus expressed a trans-acting activity after co-transfection with a recombinant plasmid carrying a bacterial chloramphenicol acetyltransferase gene under the control of a long terminal repeat of HTLV-I provirus. The trans-acting protein p40 was detected by immunoprecipitation in transfected HOS cells. Structural proteins of HTLV-I, the gag and env products, were also formed and processed in the same manner as observed in MT-2 cells. In transfected HeLa cells, the p40 protein was mainly localized in the nucleus, while other structural proteins were detected in the cytoplasm and/or the membrane by indirect immunofluorescence. Syncytium formation was observed in HeLa cells after transfection. These results demonstrated that non-lymphoid cells could produce the major proteins of HTLV-I after DNA transfection of the cloned provirus.

Antigens, Viral↗