Biomedical subjects

S Morikawa

Publications and source records attributed to S Morikawa.

At least 181 records · Page 10Linked to original sources

PubMed1991

Observation of rat hind limb skeletal muscle during arterial occlusion and reperfusion by 31P MRS and 1H MRI.

31P NMR spectra and 1H MR T1- and T2-weighted spin-echo images were concurrently observed in rat hind limb during arterial occlusion and following reperfusion. With arterial occlusion, phosphocreatine level decreased and inorganic phosphate (Pi) level increased in 31P NMR spectra. Intracellular pH's dropped as a function of time. Beta-ATP started to decrease in three hours. In six hours after the occlusion, any peaks other than Pi were scarcely detected. The signal intensities in the 1H MR images increased homogeneously in both T1- and T2-weighted conditions, but the changes were more profound with T2-weighted images. After the release of the arterial occlusion, the 31P NMR spectra recovered to the preischemic state in several hours. The 1H MR images during reperfusion showed characteristic heterogenous pattern. The signal intensities in the anterior tibial muscle and the gastrocnemius muscle remained high in T1-weighted condition and the intensities further increased in T2-weighted condition, while those in other parts returned to the preischemic level. These changes were found to be irreversible even 12 hr after the release. The high signal intensities suggested the increase of water in the extracellular compartment induced by so-called reperfusion injury. Multinuclear analysis using in vivo NMR was valuable to consecutively detect time-dependent and location-specific response in skeletal muscle during ischemia and reperfusion.

Adenosine Triphosphate↗

PubMed1991

Regulation of lymphocyte blastogenesis and antibody production by soluble factor released by a human B-lymphoblastoid cell line.

Yam 1B, a human B lymphoblastoid cell line, spontaneously produced an immunoregulatory factor, which suppresses blastogenesis and antibody formation by human lymphocytes. The Yam 1B cells, which were derived from the peripheral blood of an adult T-cell leukemia patient, have been established and maintained in our laboratory since 1985. This cell line expressed mature B-cell surface antigens including surface immunoglobulin M (IgM), CD23, and HLA-DR; had cytoplasmic IgM; and secreted small amounts of IgM in the culture supernatants. Yam 1B was positive for Epstein-Barr virus-associated antigen (EBNA) but negative for adult T-cell-associated antigen (ATLA). The serum-free Yam 1B culture supernatants (SN) inhibited the expression of transferrin R, but neither the expression of interleukin 2 (IL-2) R(CD25) nor the production of IL-2 in the lymphocytes stimulated with phytohemagglutin. Yam 1B SN also inhibited DNA synthesis by human T and B lymphocytes and immunoglobulin generation by normal B cells as well as by Epstein-Barr virus-transformed human B lymphoblastoid cell lines. The inhibitory activity of Yam 1B SN was inactivated at 56 degrees C and at pH 10 but was relatively stable at pH 2. It was abrogated by digestion with pronase and was partially stable by digestion with trypsin. Fractions collected from a Sephacryl S-300 gel filtration column (Pharmacia Fine Chemicals, Uppsala, Sweden) were found to have a peak of inhibitory activity of cell proliferation associated with molecules of apparent MWr of 43,000 to 67,000. The inhibitory activity of Yam 1B SN was not blocked by the anti-transforming growth factor beta antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗

PubMed1991

17D yellow fever vaccine virus envelope protein expressed by recombinant baculovirus is antigenically indistinguishable from authentic viral protein.

We have constructed a recombinant baculovirus containing cloned DNA encoding the membrane and envelope (E) proteins of 17D yellow fever vaccine virus. Spodoptera frugiperda cells infected with this recombinant baculovirus produced a 66K protein which corresponded to the estimated size of the protein encoded by the cloned inserted DNA, and a 54K protein with the same molecular size as that of the authentic 17D yellow fever virus E protein. This recombinant 54K protein was labile, producing E protein-specific breakdown products (45K to 36K). Indirect immunofluorescence, using a panel of E protein-specific monoclonal antibodies, showed that the recombinant protein was presented both inside as well as on the surface of cells and was antigenically indistinguishable from the E protein of 17D yellow fever vaccine virus.

Animals↗

PubMed1991

The role of CD45RA on human B-cell function: anti-CD45RA antibody (anti-2H4) inhibits the activation of resting B cells and antibody production of activated B cells independently in humans.

Anti-CD45RA antibody defined by anti-2H4 monoclonal antibody has been reported to split CD4+T cells into two distinct subpopulations. CD45RA antigen is present on the surface of virtually more than 95% B lymphocytes in the purified tonsillar B-cell preparations. We examined the role of CD45RA antigen on human B-cell function using this antibody. The addition to anti-2H4 to tonsillar B cells inhibited the proliferative response induced by Staphylococcus aureus Cowan strain I(SAC) in a dose-dependent manner. Kinetic analysis indicated that anti-2H4 exerted its inhibitory effect when added within the first 24 h of culture initiation during a 72-h culture period. Anti-2H4 inhibited the transferrin receptor expression without interfering with the expression of the IL-2 receptor on SAC-stimulated B cells in a short-term culture. Anti-2H4 blocked the progress of SAC-stimulated B cells from the G1 to S phase of the cell cycle. These events suggested that anti-CD45RA MoAb inhibited the proliferative response by directly acting on B cells in the G1 phase. In addition, anti-CD45RA antibody also had a suppressive effect on early phase of B-cell differentiation. This effect appeared to be independent of its suppressive effect on proliferation, because anti-CD45RA did not inhibit the proliferative response of preactivated B cells with lymphokines. These studies suggested that the restricted epitope recognized by anti-2H4 antibody may be directly involved in regulatory function on B cells.

Antibodies, Monoclonal↗

PubMed1991

Analysis of common epitopes on gag proteins of HIV-1, HIV-2 and SIV[AGM] using monoclonal antibodies against HIV-1.

Five monoclonal antibodies (MoAbs) to gag proteins of HIV-1 were prepared in mice. Western blot analyses showed that three clones recognized p24 and the other two p17. Among the three MoAbs recognizing p24, all recognized two of three strains of HIV-2. The spectra of reactions to SIV[AGM] of these MoAbs against p24 were different from one to another; K3-24 recognized all four strains of SIV[AGM], L6-24 three of them, and K5-24 none of them. Of the two MoAbs recognizing p17, K7-17 recognized two of the three strains of HIV-2 but not any SIV[AGM] strain, and the other clone, L14-17 recognized none of analogous proteins of HIV-2 nor of SIV[AGM]. These results demonstrate that the gag proteins of HIV-2 and SIV[AGM] share some common epitopes with those of HIV-1 which are heterogenic in some degree among the different isolates.

Animals↗

PubMed1991

Dye-sensitized photooxidation of neutral protease from Bacillus subtilis var. amylosacchariticus: assignment of histidine residue oxidized.

The neutral protease of Bacillus subtilis var. amylosacchariticus was photooxidized in the presence of methylene blue, by which treatment the enzyme was rapidly inactivated. The inactive enzyme was digested with endoproteinase Asp-N, the resultant peptides were separated by HPLC, and their amino acid sequences were compared with those obtained from the unmodified enzyme. Of four peptides that contained histidine residues, only the recovery of one peptide was found to be decreased by the photooxidation with the appearance of a new peptide. Comparisons of amino acid compositions and sequences between these two peptides showed that the latter peptide lacked His228 of the former one, indicating that His228 was photooxidized. This result suggests that His228 is involved in the catalytic reaction of the neutral protease or interaction with substrates.

Amino Acid Sequence↗

PubMed1991

Chemical modification of neutral protease from Bacillus subtilis var. amylosacchariticus: assignment of tyrosyl residues iodinated.

The neutral protease of Bacillus subtilis var. amylosacchariticus (B. amylosacchariticus) was iodinated with a 25-fold molar excess of iodine at pH 9.4 for 3 min at 0 degree C, by which treatment the proteolytic activity toward casein was markedly reduced, while the hydrolytic activity toward an N-blocked peptide substrate was rather increased. The modified enzyme was digested with Staphylococcus aureus V8 protease at pH 8.0 and the amino acid sequences of resultant peptides were compared with those obtained from the native enzyme. One of the peptides was found to have an amino acid sequence of Thr-Ala-Asn-Leu-Ile-Tyr-Glu, which corresponds to residue Nos. 153-159 of the enzyme, where Tyr-158 was identified to be mono-iodotyrosine. The other two peptides were those containing Tyr-21 which was mono- and di-iodinated, respectively. Referring to nitration experiments on the neutral protease and the active site structure of thermolysin, it was concluded that the iodination of Tyr-158 is mainly responsible for the activity changes of B. amylosacchariticus neutral protease.

Amino Acid Sequence↗

PubMed1991

The role of CD45 in the activation, proliferation and differentiation of human B lymphocytes.

We examined the role of CD45 antigen in human B cell function, using the anti-CD45 antibody, T29/33. The addition of T29/33 to B cells inhibited the proliferative response induced by various polyclonal B cell activators in a dose-dependent manner at concentrations of 0.01 to 10 micrograms/ml. Kinetic analysis indicated that T29/33 exerted its inhibitory effect when added within the first 24 h of culture initiation during a 72-h culture period, but had little effect when added at 48 h. Pre-treatment of high-density B cells with T29/33 antibody for 48 h showed a marked inhibitory effect on the proliferative response of these B cells when they were subsequently stimulated with SAC. Antibody to CD45 appeared to block the G0(G1) to S phase transition in the cell cycle analysis by propidium iodide staining. T29/33 antibody suppressed the RNA and DNA synthesis induced by SAC stimulation in B cells. These data suggested that small resting B cells were sensitive to anti-CD45-induced suppression. T29/33 antibody also suppressed immunoglobulin synthesis in B cells, independently of its suppressive effect on proliferation. These results indicated that CD45 antigen defined by T29/33 is involved in the activation, proliferation, and differentiation signals of human B lymphocytes.

Antigens, CD↗

PubMed1991

Biological function of recombinant IL-6 expressed in a baculovirus system.

The cDNA of human interleukin-6 (IL-6) was cloned into baculovirus DNA. Insect cells (Spodoptera frugiperda cells) infected with the recombinant baculovirus secreted a large amount of 22K protein into the culture medium. This culture fluid contained high biological activity of growth stimulation of a mouse myeloid cell line (MH-60). The IL-6 was purified by a one-step procedure employing immunoaffinity chromatography of monoclonal antibody to IL-6. The specific activities (BSF-2 reference units/mg protein) of the original culture medium and the purified material from the one-step purification were 0.3-1 x 10(6) and greater than 2 x 10(7), respectively. The highly purified IL-6 could not induce an antiviral state in human diploid fibroblast (FS-4) cells.

Amino Acid Sequence↗

PubMed1991

Induction of non-MHC-restricted cytotoxicity in a patient with pure red cell aplasia: functional relevance to antigen-specific cytotoxic T cells.

A functional analysis of an expanded T-cell subpopulation was studied in a patient with pure red cell aplasia who had no evidence of malignancy. In the time of an aggravation of the anemia, an expanded population of large granular lymphocytes (LGL) with T-cell receptor (TCR) alpha beta +CD3+CD8+ phenotype was noted, which reverted to normal with remission. These T cells displayed a polyclonal pattern in DNA analysis. Functionally, the T cells, with suppressor/cytotoxic phenotype exhibited normal capabilities for transducing the signals of the proliferative response, and of interleukin-2R (IL-2R) expression and IL-2 production via the TCR-CD3 complex structure. While they suppressed erythroid colony formation in vitro, neither non-major histocompatibility complex-restricted cytotoxic activity, cytotoxic T-cell activity, nor suppressive activity for immunoglobulin synthesis by B cells was detected. Pretreatment by anti-CD3 or anti-T-cell receptor antibody generated cytotoxicity for FcR+ target cells in the patient cells, but no such augmentation was found with other monoclonal antibodies of FcR- target cells. These findings indicated that the expanded T cells are functionally relevant to antigen-specific cytotoxic T lymphocytes.

Adult↗

PubMed1990

Truncoumbilical bypass of the portal vein in radical resection of biliary tract tumour involving the hepatic duct confluence.

Before combined resection of the right hepatic lobe and the hepatoduodenal ligament, an autogenous external iliac vein was interposed between the root of the portal vein trunk and the umbilical portion of the vein in four patients with biliary tract tumour. The left hepatic arterial pathway was preserved, except in one case in whom resection of this artery was followed by reconstruction. This procedure allowed successful and safe extended right hepatic lobe resection and combined en bloc resection of the hepatoduodenal ligament while preserving hepatic blood perfusion.

Adenoma, Bile Duct↗

PubMed1990

Identification and nucleotide sequence of the gene encoding a surface antigen induced by vaccinia virus.

The gene encoding the specific antigen (S antigen) induced on the surface of vaccinia virus-infected cells was mapped on the viral genome by the construction of recombinant viruses. The S gene is located in the 1.5-kbp XbaI-AccII fragment between 11.1 and 12.6 kbp from the right end of the viral genome. Nucleotide sequencing of the fragment revealed an open reading frame (ORF) of 351 codons capable of producing a polypeptide with a molecular weight (MW) of 40,701 Da. Mapping of the S mRNA by primer extension indicates the presence of the transcription initiation site that precedes the translation initiation codon by 14 nucleotides. The region preceding the S mRNA start site is extremely A/T-rich and has sequence similarity with other early genes. The signal for termination of transcription of the early genes, TTTTTAT, is included near the end of the ORF. The deduced amino acid sequence contains a typical membrane signal characterized by a hydrophobic region in the N-terminus. An early polypeptide with a MW of 40 kDa, in agreement with the size predicted from the ORF, was synthesized by cell-free translation of the mRNA selected by hybridization to a plasmid containing the region of the ORF.

Amino Acid Sequence↗

PubMed1990

Functional analysis of clonally expanded CD8, TCR gamma delta T cells in a patient with chronic T-gamma lymphoproliferative disease.

Leukemic cells from a patient with T-gamma lymphocytosis were found to have the surface phenotype, CD3+, CD4-, CD8+, Leu19+, TCR delta 1+, WT31-. The clonal nature of the TCR gamma delta T cell proliferation was documented by flow cytometry and Southern blot analysis. Morphologically, they were large to medium-sized mature lymphocytes with cytoplasmic granules. Functionally, the cells revealed strong cytotoxic activities against NK-sensitive target cells, but had neither killer T cell activity nor suppressive activity on PWM-driven immunoglobulin synthesis by B cells. Interestingly, both suppressive and cytotoxic T cell activities were recovered with the depletion of CD8+ T cells. These studies may suggest some functions of the CD8+ population of human TCR gamma delta T cells in a normal immune system.

Aged↗

PubMed1990

Characterization of baculovirus-expressed Rift Valley fever virus glycoproteins synthesized in insect cells.

A cDNA corresponding to the complete coding region of the M RNA of the M12 mutant of Rift Valley fever virus (RVFV) strain ZH548 (K. Takehara, M-K. Min, J.K. Battles, K. Sugiyama, V.C. Emery, J.M. Dalrymple, and D.H.L. Bishop, Virology, 169, 452-457, 1989) has been inserted into the baculovirus transfer vector pAcYM1. By comparison with the parent RVFV, the M RNA of the M12 mutant has a new small open reading frame (ORF1) upstream of the one that initiates the precursor of the viral glycoproteins (ORF2, gene order: NS(M)-G2-G1). A derivative of the M12 cDNA was prepared from which most of the upstream sequences (including a polyT tract and ORF1) were removed. Other cDNA constructs were made from this derivative, constructs in which most of the G1 sequences were also removed, or most of the NS(M) coding sequences, or all of the NS(M) and most of G2 coding sequences. Each RVFV M cDNA construct was inserted into a pAcYM1 transfer vector and recombinant baculoviruses were produced (RVM1-5). The derived viruses were employed to study the expression and properties of the RVFV glycoproteins in Spodoptera frugiperda insect cells. For each recombinant virus evidence was obtained which indicated that the RVFV glycoproteins were produced and processed in the insect cells. Although four of the recombinants gave low expression levels of the RVFV glycoproteins, for the vector that made only the G1 product, the expression level was significantly higher. Immunofluorescence analyses established that the RVFV glycoproteins were present both at intracellular locations and on the surface of the recombinant baculovirus infected insect cells.

Animals↗

PubMed1990

Shorter size of transmembrane glycoprotein of an HIV-1 isolate.

An HIV-1 strain carrying a shorter form of the transmembrane glycoprotein (TM) with a mobility of 32 kD, named KB-1, was isolated from a Japanese male hemophiliac by coculture of his peripheral blood mononuclear cells (PBMCs) with MT-2 cells and adaption to TALL-1 cells. Another HIV-1 strain, named KB-2, was isolated from his seropositive spouse by coculture of her PBMCs with MT-2 cells. The KB-2 strain carried a TM of ordinary size, with a mobility of 41 kD. The KB-1 strain carrying a truncated form of the TM could replicate in MT-2, MT-4, TALL-1 and MOLT-4 cells. The KB-1 strain is a useful HIV-1 isolate for investigating the function of the cytoplasmic domain of the TM and the significance of the presence of an in-frame stop codon in HIV env gene.

Blotting, Western↗

PubMed1990

Inhibitory effect of novel 1-deoxynojirimycin derivatives on HIV-1 replication.

The effect of 11 derivatives of 1-deoxynojirimycin (DNM) on the replication of HIV-1 was studied. Compared with DNM, seven of them showed remarkable inhibition of HIV-1-induced syncytium formation at significantly low concentrations which were not cytotoxic. Two derivatives were found to markedly reduce the infectious virus yields from cell lines chronically infected with HIV. Analysis of HIV-1 envelope glycoproteins showed that the derivatives induced modification of the processing of not only gp120/160 but also the transmembrane glycoprotein gp41. The modification of the processing of the transmembrane glycoprotein gp41 might play an important role in the inhibition of virus replication at a step after the binding of gp120 to CD4. The enhanced anti-HIV activity of DNM derivatives reported here could increase the possibility of non-toxic therapeutic intervention in HIV infections.

1-Deoxynojirimycin↗

PubMed1990

Expression of leukocyte common antigen (CD45) on various human leukemia/lymphoma cell lines.

CD45 antigen (leukocyte common antigen), a unique and ubiquitous membrane glycoprotein with a molecular mass of about 200 kDa, is expressed on almost all hematopoietic cells except for mature erythrocytes. However, the biological function of this glycoprotein still remains to be resolved. In order to clarify the role of CD45 antigen in hematopoietic cell differentiation and function, its expression on human leukemia/lymphoma cell lines was studied by membrane immunofluorescence. Thirty-eight established cell lines were analyzed using T29/33, a monoclonal antibody (MoAb) that recognizes the common epitopes of this glycoprotein molecule. Conventional cell marker studies were also carried out on these cell lines to compare their CD45 expression. It was shown that CD45 expression varies among B-lineage cells depending on cell differentiation, in contrast to its stable expression on leukemic T cell (6/6, positive) and myeloid (5/5, positive) lineage cell lines. On the other hand, only two out of six histiomonocytoid lineage cell lines were positive. Human T cell leukemia/lymphoma virus type I (HTLV-I)-associated T cell lines derived from peripheral blood leukocytes of patients with adult T cell leukemia/lymphoma (ALT/L) in Japan did not express CD45 on their cell surface. Taken together, these observations suggest that CD45 has a functional role in hematopoietic cell activation and differentiation.

Adult↗

PubMed1990

[Study of the fine structure of human deciduous dentin with dentinogenesis imperfecta, with special reference to the mantle dentin].

A lower deciduous incioer exhibiting dentinogenesis imperfecta (D.I) obtained from a 6-year-old boy with osteogenesis imperfecta (Shields' Type I) was examined by means of light microscopy (LM), scanning electron microscopy (SEM), and X-ray microanalysis (XMA). With LM, the dentin displayed a sparse and irregular tubular pattern near the dentino-enamel junction (DEJ) and only few or no tubular structures in the area corresponding to the circumpulpal dentin. Between these two areas, cleft-like structures were characteristically noted. Structural irregularities in the dentinal tubules were also shown with SEM observation. XMA demonstrated that the distribution of both Ca and P in the dentin of DI teeth was apparently lower than that in the normal deciduous incisor used as a control. Specifically, an area along EDJ at a distance of 25-35 microns, corresponding to the mantle dentin, revealed extremely low or no distribution of the both elements. From the present observation, it is suggested that the generic disorder mainly involved in the primary odontoblasts and consequently results in the disturbance of calcification, especially that mediated by the matrix vesicles, and shortening of the cell life. After the death of these cells, the cells originate in, from the undifferentiated pulp cells may participate in the deposition of another irregular dentin.

Calcium↗