Biomedical subjects

M Satoh

Publications and source records attributed to M Satoh.

At least 631 records · Page 35Linked to original sources

PubMed1993

A vaccinia virus vector for efficiently introducing into hippocampal slices.

We have developed a novel technique using vaccinia virus for highly efficient introduction of foreign genes into viable cells of brain slice to study function of nervous system. Hippocampal slices of adult guinea pigs were infected with a vaccinia virus carrying a gene for beta-galactosidase (beta-gal) as a reporter gene. Expression of beta-galactosidase was first detected after 5 hours and reached maximum after 16 to 24 hours. Light microscopic observation revealed that beta-galactosidase was expressed uniformly in the CA1-CA3 pyramidal cell layer, granule cell layer of dentate gyrus and glial cells. Serial sections of infected slices showed that cells were uniformly infected throughout the thickness of the slice. Thus, the vaccinia virus system provides a convenient gene transfer tool for studying brain function in cultured slice system.

Animals↗

PubMed1993

Detection of capsaicin-evoked release of glutamate from spinal dorsal horn slices of rat with on-line monitoring system.

We examined whether capsaicin evokes the release of glutamate from unmyelinated primary afferent fibers, using a fluorometric on-line monitoring system, in which immobilized glutamate dehydrogenase column was connected to an in vitro superfusion system. In this system, an application of capsaicin (1 microM) resulted in an increased outflow of glutamate from dorsal horn slices in a tetrodotoxin-resistant manner, while capsaicin (3 microM) was without effect on ventral horn slices. This effect of capsaicin on the dorsal horn slices was in a concentration-dependent manner at 0.1-3 microM and the effect at 10 microM was not larger than that at 3 microM. The competitive capsaicin antagonist capsazepine significantly reduced the release of glutamate evoked by 1 microM capsaicin. Twice exposures of dorsal horn slices to capsaicin led a significant decrease in the release of glutamate evoked by the second capsaicin stimulation, indicating desensitization to capsaicin. Thus, using on-line monitoring system, we actually demonstrated that capsaicin induced the release of glutamate from the dorsal horn, probably from capsaicin-sensitive primary afferent terminals.

Animals↗

PubMed1993

Modulation of both cisplatin nephrotoxicity and drug resistance in murine bladder tumor by controlling metallothionein synthesis.

The role of metallothionein (MT) in cisplatin (cis-DDP) resistance and renal toxicity was investigated in C3H mice inoculated with mouse bladder tumor (MBT-2). C3H mice were inoculated s.c. with 1 x 10(6) MBT-2 cells/mouse on day 0. Mice were given injections of proparglyglycine (PPG) (500 mumol/kg s.c.) once a day for 3 days from day 7 to day 9 and with ZnSO4 (200 mumol/kg s.c.) once a day for 2 days from day 8 to day 9. cis-DDP (50 mumol/kg i.p.) was administered 10 days after MBT-2 cell inoculation. Since MT contents in the tumor and kidneys were significantly increased by administration of ZnSO4, both the antitumor activity of cis-DDP and its renal toxicity were reduced. However, coadministration of PPG reduced MT induction in tumor without affecting the level of renal MT. As a result, PPG could clearly overcome the MT-mediated cis-DDP resistance of tumors without compromising the protective effect exerted by renal MT on nephrotoxicity of the drug. It was suggested, therefore, that PPG may be a promising adjunct in cancer chemotherapy to overcome the drug resistance of tumors caused by the elevated level of MT.

Alkynes↗

PubMed1993

Expression of bone morphogenetic protein in human adenocarcinoma cell line.

A subclone termed as HSG-S8 was previously isolated from human salivary adenocarcinoma cell line, HSG, and proliferated in a serum-free culture. When HSG-S8 and parental HSG cells were transplanted into nude mice i.m. or s.c., both cells reproducibly induced adenocarcinoma. Furthermore, injection of HSG-S8 consistently induced formation of cartilage i.m. or bone s.c. in tumors, but did not parental HSG cells. The cytoplasm of HSG-S8 cells was specifically immunostained by anti-bone morphogenetic protein (BMP)-2 antibody. The conditioned medium of HSG-S8 cells contained a protein of M(r) 18,000 which specifically reacted with anti-BMP-2 protein antibody. Northern blot analysis also revealed that HSG-S8 cells expressed transcripts for BMP-2. On the other hand, parental HSG cells gave a very slightly positive signal only in Northern blot analysis. These results indicate that HSG-S8 cells synthesize and secrete BMP-2 protein, which is probably involved in the formation of cartilage and bone in the tumor tissues in nude mice.

Adenocarcinoma↗

PubMed1993

Establishment of apoptosis-inducing monoclonal antibody 2D1 and 2D1-resistant variants of human T cell lines.

A monoclonal antibody (mAb), 2D1(IgM), was identified for its anti-proliferative effect on human T leukemia cell line, SUP-T13. The cells bound with 2D1 showed DNA ladder patterns of oligonucleosomes, demonstrating apoptosis. Peripheral mononuclear cells activated by phytohemagglutinin or OKT3 induced expression of 2D1 antigen and were growth-inhibited by the antibodies. Among the cell lines tested, T cell lines tended to be growth-inhibited by the antibodies. Epstein-Barr virus-transformed B cells were reactive with 2D1, but were not growth-inhibited by the antibodies. We established stable 2D1-resistant variants LAC2D1R and JKT2D1R from the original SUP-T13 and Jurkat T cell lines, respectively. These variant cells demonstrated phenotypes identical to the original cells, including reactivity to 2D1 and expression of cytoplasmic Bc1-2 protein. The 2D1-resistant cells were as sensitive as the original cells to the other apoptosis-inducing stimuli, such as gamma-irradiation or calcium ionophore A23187. However, the 2D1-resistant variants were also insensitive to anti-Fas, another apoptosis-inducing mAb. Binding of 2D1 was blocked by anti-Fas mAb, suggesting that 2D1 reacts with an epitope of human Fas molecules. The present results demonstrate that a 2D1-reactive, but not 2D1-sensitive, population may exist in highly 2D1-sensitive human leukemia T cells and that pairs of 2D1-sensitive and 2D1-resistant cells are useful in the biochemical analysis of Fas-mediated apoptosis in human T cells.

Antibodies, Monoclonal↗

PubMed1993

In vitro DNA synthesis of mouse hepatocytes stimulated by tumor necrosis factor is inhibited by glucocorticoids and prostaglandin D2 but enhanced by retinoic acid.

We have recently shown that TNF is produced in liver rapidly after partial hepatectomy and that TNF can stimulate DNA synthesis of hepatocyte primary culture with its inhibition by interleukin 6 and transforming growth factor-beta, indicating a pivotal role of TNF and TNF-driven cytokine induction in liver regeneration. We here examined the effects of biological or inflammatory mediators of low molecular weight on the in vitro DNA synthesis of hepatocytes stimulated by TNF. Simultaneous addition of dexamethasone markedly suppressed the growth-stimulating action of TNF, maximally at 10(-7) M and effectively at about 10(-8) M. However, the growth-stimulating effect of EGF was not affected by dexamethasone at all. Physiological glucocorticoids, corticosterone, and hydrocortisone showed virtually the same effect, but other steroid hormones, beta-estradiol, or progesterone did not. Retinoic acid at 10(-7) M, however, enhanced TNF-stimulated hepatocyte DNA synthesis and even more effectively the growth response to EGF. PGD2 at 20 microM was markedly suppressive but PGE2 was not. The addition of indomethacin enhanced the hepatocyte in vitro growth by TNF and EGF at 2-20 microM. These results indicate that the growth of hepatocytes stimulated by TNF is up- and down-regulated by inflammatory mediators and hormones as well as cytokines and suggest the biological significance of TNF and TNF-driven inflammatory reactions in liver regeneration.

Animals↗

PubMed1993

Modulation of the phosphorylation of glucose-regulated protein, GRP78, by transformation and inhibition of glycosylation.

The phosphorylation of glucose-regulated protein, GRP78, is thought to be involved in the regulation of the binding function of GRP78 to immunoglobulin heavy chains. The phosphorylation of GRP78 proceeded faster in transformed cells than in normal cells, whereas the levels of GRP78 synthesis and accumulation were similar in both cells. Treatment of the cells with tunicamycin caused a rapid decrease in GRP78 phosphorylation within 2 to 4 h in both cell types prior to GRP78 induction. Following a longer period of tunicamycin treatment, GRP78 phosphorylation recovered gradually in parallel with the accumulation of newly synthesized GRP78. The half-life of GRP78 was over 24 h and similar in both normal and transformed cells either with or without tunicamycin treatment. In contrast, the half-life of phosphate groups incorporated into GRP78 was about 120 min in both types of cells in the absence of tunicamycin treatment. When the cells were treated with tunicamycin, the half-life of the phosphate groups was shortened (-30 min) only in transformed cells, while it remained at untreated control levels in normal cells. These results suggest that GRP78 phosphorylation is important in functional regulation, and that the cells may carry out particular requirements such as increasing or decreasing secretory proteins by modulating GRP78 phosphorylation rather than GRP78 synthesis.

3T3 Cells↗

PubMed1993

Histochemical demonstration of copper in LEC rat liver.

Livers of LEC rats were histochemically stained for copper according to the modified Timm's method, which includes trichloroacetic acid (TCA) treatment. TCA pretreatment was effective in removing zinc and iron, leaving as the major metal in the liver. Hepatocytes in 3-month-old rats were stained intensely by the modified Timm's method, both in frozen sections and in paraffin-embedded specimens. The centrilobular hepatocytes were usually stained, but positive cells were also randomly distributed in the hepatic lobes, showing a mosaic pattern. The staining was intensified in 8- compared to 3-month-old LEC rats. In contrast hepatocytes from LEA rats, the normal counterpart of LEC rats, were faintly stained for copper. Proliferating cholangioles found in older LEC rats were shown to lack copper deposition, and hepatocellular carcinoma showed less copper deposits than the hepatocytes surrounding the tumor. The copper staining was augmented in livers of LEC rats subjected to copper-loading, but was less intense in the livers treated with D-penicillamine. The staining intensity under the various experimental conditions showed good correlation with the copper concentration. Lysosomal deposition of copper in hepatocytes was demonstrated by electron microscopic analysis for copper. Thus the modified Timm's method was shown to produce valuable results in demonstrating copper in LEC rat livers, providing important information for an understanding of the mechanism of copper deposition and hepatic disease of the animal.

Animals↗

PubMed1993

Stable production of recombinant pro-urokinase by human lymphoblastoid Namalwa KJM-1 cells: host-cell dependency of the expressed-protein stability.

Human pro-urokinase (pro-UK) gene was engineered for expression in mammalian cells. The stability of recombinant pro-UKs produced by two kinds of cells, Chinese hamster ovary (CHO) and human lymphoblastoid Namalwa KJM-1 cells, were compared. The pro-UK expressed in CHO cells in serum-free medium was degraded by cysteine endopeptidase secreted by CHO cells. This endopeptidase was inhibited by p-chloromercuribenzonate (PCMB) and leupeptin more efficiently than by aprotinin. On the other hand, the pro-UK expressed in Namalwa KJM-1 cells was not degraded, resulting in the stable production of pro-UK at a rate of 2-3 micrograms/10(6) cells/day by use of a gene amplification method with dihydrofolate reductase (DHFR) in serum-free medium. Thus, Namalwa KJM-1 cells showed the desired characteristics as a host cell for the production of recombinant proteins. The stability of recombinant proteins in heterologous systems may vary depending on the host cells.

Amino Acid Sequence↗

PubMed1993

Murine monoclonal antibodies specific for conserved and non-conserved antigenic determinants of the human and murine Ku autoantigens.

The Ku autoantigen is a DNA binding factor consisting of 70 and approximately 80 kDa proteins (p70 and p80, respectively) which form a heterodimer. The p70/p80 dimer appears to be crucial for the function of a 350 kDa DNA-dependent protein kinase (DNA-PK) that phosphorylates certain transcription factors in vitro. Previous studies have suggested that Ku is abundant in primate cells, but undetectable in most non-primate cells. However, it is unclear if this reflects low abundance of Ku (and possibly DNA-PK activity) in non-primate cells, a lack of antibodies crossreactive with non-primate Ku proteins, or both. Ku was first identified with human autoimmune sera, but the suitability of these sera for studying the distribution, abundance and function of Ku is limited by the polyclonal immune response to Ku and the presence of contaminating autoantibodies in most patients' sera. In the present studies, we determined the specificities of murine anti-Ku monoclonal antibodies (mAbs) using cellular Ku as well as recombinant human and murine Ku antigens. Immunofluorescence studies confirmed previous observations that Ku is undetectable in most nonprimate cells. However, small amounts of Ku could be detected in MOPC-315, but not L-929, cells by immunoprecipitating with mAb 162. In addition, autoantibodies to Ku were identified in the sera of approximately 1/3 of MRL/lpr mice. The murine autoantibodies also immunoprecipitated a small amount of Ku (comparable to that seen with 162) from MOPC-315, but not L-929, cell lysates. Characterization of the mAb specificities by immunoblot analysis with Ku fusion proteins revealed that mAbs 111, S10B1, and N9C1 bound to distinct epitopes of human p80 (amino acids 610-705, 8-221, and 1-374, respectively). All three mAbs were unreactive with murine p80. MAbs N3H10 and S5C11 bound immediately adjacent to the DNA binding site of p70 (amino acids 506-541). Only N3H10 displayed comparable reactivity with human and murine p70 on immunoblots, but it immunoprecipitated murine Ku poorly. S5C11 crossreacted more weakly with murine p70 on immunoblots, whereas 162 was completely unreactive with human or murine Ku on immunoblots, despite immunoprecipitating Ku efficiently. Studies with mAbs N3H10 and 162 suggest that the level of Ku is considerably lower in nonprimate cells than cells of primate origin, and that L-929 cells express little or no Ku protein.(ABSTRACT TRUNCATED AT 400 WORDS)

3T3 Cells↗

PubMed1993

A case of Sjögren's syndrome complicating immune-mediated aplastic anaemia.

A 78-year-old Japanese woman with Sjögren's syndrome complicating immune-mediated aplastic anaemia is described. A diagnosis of aplastic anaemia was made from severe pancytopenia with hypoplastic marrow. Laboratory studies suggested an association of bone marrow suppressive T-lymphocytes with the pathogenesis of aplastic anaemia. Following the administration of mepithiostan and prednisolone, pancytopenia improved gradually. Two years after the onset of aplastic anaemia, Raynaud's phenomenon developed and examinations revealed the existence of keratoconjunctivitis sicca and anti-SSA/Ro and anti-SSB/La antibodies.

Aged↗

PubMed1993

Chronic destructive monoarthritis of the wrist in patients with anti-SSA/Ro antibodies: report of two cases.

Among 340 patients with rheumatic diseases, two cases of chronic destructive monoarthritis of the wrist with anti-SSA/Ro antibodies and rheumatoid factor, were observed for over three years. It is not clear whether these cases represent a specific subset of rheumatoid arthritis (RA) or whether they may progress to diffuse symmetrical destructive polyarthritis typical of RA. Long-term follow-up studies including analysis of autoantibodies will be needed to clarify the characteristics and course of chronic monoarthritis.

Antibodies, Antinuclear↗

PubMed1993

Marked thrombocytosis with chromosomal abnormalities in a patient with rheumatoid arthritis.

An 80 year-old Japanese woman with rheumatoid arthritis (RA), complicated with thrombocytosis is described. Mild to moderate thrombocytosis is commonly observed in patients with RA, but she had marked thrombocytosis of over 1000 x 10(3)/mm3 and monosomy 22 with marker chromosome. This case suggests that thrombocytosis unusual with disease activity of RA might occur, and that careful evaluation of the thrombocytosis is required.

Aged↗

PubMed1993

Benzodiazepine inverse agonists augment long-term potentiation in CA1 and CA3 of guinea pig hippocampal slices.

The effects of benzodiazepine inverse agonists on the long-term potentiation of synaptic transmission in hippocampal slices of the guinea pig were examined using an extracellular recording technique. Benzodiazepine inverse agonists, beta-carboline-3-carboxylate (beta-CCE), 2-phenylpyrazolo [4,3-c]quinolin-3(5H)-one (CGS-8216) and 2-[5-methylthien-3-yl]-2,5-dihydro-3H-pyrazolo [4,3-c]quinolin-3-one (S-135), augmented the magnitude of long-term potentiation induced by tetanic stimulation of input fibers in both the CA1 and the CA3 regions. beta-Carboline-3-carboxylate was more effective in augmenting long-term potentiation in CA1 than in CA3. Augmentation of long-term potentiation produced by beta-CCE was antagonized by concomitant application of flumazenil, a benzodiazepine receptor antagonist. Therefore, the enhancing action of benzodiazepine inverse agonists on long-term potentiation, which is suggested to be a specific action, mediated by the GABA/benzodiazepine receptor complex, might help to explain the mechanism of the memory-enhancing effects of benzodiazepine inverse agonists, observed in some in vivo behavioral paradigms.

Animals↗

PubMed1993

Linac-based small-field radiotherapy for brain tumors.

Small-field radiotherapy based on a 6-MeV linac and a conventional head mold is investigated as an alternative to radiosurgery with stereotactic frames. The system requires no additional device and allows fractionated treatment. The dose distributions obtained are comparable to those reported with a Gamma Unit. Overall positioning errors are within 2 mm. Using this approach, seven patients with brain tumors who could not have been treated otherwise, underwent fractionated radiotherapy with total accumulated doses ranging from 70 to 108 Gy. The treatment was tolerated well with no acute toxicity or adverse effect encountered during the follow-up period of 8-14 months. All of the patients remained free from disease progression in the treated volumes. Although the follow-up is brief, the preliminary results suggest that this is a simple and inexpensive but effective system for the treatment of small intracranial malignancies.

Brain Neoplasms↗

PubMed1993

In situ hybridization study of interleukin-1 beta mRNA induced by kainic acid in the rat brain.

The distribution patterns of interleukin-1 beta (IL-1 beta) mRNA in various brain regions of saline- and kainic acid-treated rats were examined using in situ hybridization technique. In normal rat brain, the signals of IL-1 beta mRNA were observed in the cerebellar Purkinje cells and in dispersed cells in the hypothalamus. In the case of the kainic acid treatment, IL-1 beta mRNA was intensely induced in the olfactory bulb, lateral septum, thalamus, hypothalamus, polymorphic layers of hippocampus, piriform cortex, amygdala, entorhinal cortex and cerebral cortex at 2 h after the injection of kainic acid. In the hypothalamic region, we observed the induction of IL-1 beta mRNA around the paraventricular hypothalamic nucleus, anterior hypothalamic area, dorsomedial and ventromedial hypothalamic nucleus, mammillary regions and arcuate nucleus. The signal of IL-1 beta mRNA was still expressed 4 h after treatment with kainic acid, less intensely than at 2 h, but above the control level. In these regions, IL-1 beta mRNA was expressed mainly in the glial cells, which were densely stained by Cresyl violet and did not contain glial fibrillary acidic protein. These results suggest that IL-1 beta is produced by a certain type of glial cells, maybe microglia, and might have regulatory functions in the central nervous system.

Animals↗

PubMed1993

Contractile responses and calcium movements induced by alpha 1-adrenoceptor stimulant, norepinephrine, in rabbit iris dilator muscle.

1. The mechanisms involved in contraction of rabbit iris dilator muscle induced by norepinephrine (NE) were studied. 2. The concentration-response curve of NE was not influenced by Ca2+ blockers in the normal physiological saline solution (PSS) and removal of Ca2+ from PSS. 3. In 0.01 mM EGTA containing Ca(2+)-free PSS, the NE-induced contraction was phasic, which was suppressed by TMB-8, cyclopiazonic acid, ionomycin and A23187 but still partly remained. 4. In 2 mM EGTA containing Ca(2+)-free PSS, NE increased the intracellular Ca2+ ([Ca2+]i) and muscle tension. Ryanodine abolished the increase in [Ca2+]i induced by NE but slightly inhibited the tension. 5. These results suggest that the NE-induced contraction of rabbit iris dilator in normal PSS is mainly due to the increase in the release of intracellularly sequestered Ca2+ and partly due to the Ca(2+)-independent processes.

Adrenergic alpha-Agonists↗

PubMed1993

Detection of Epstein-Barr virus DNA and EBV-determined nuclear antigen in angioimmunoblastic lymphadenopathy with dysproteinemia type T cell lymphoma.

Six cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like T cell lymphoma were analyzed by immunohistochemical staining, polymerase chain reaction (PCR) and Southern blot analysis. Five cases out of six showed gene rearrangements of the T cell receptor beta chain, indicating the existence of a clonal T cell proliferation. Epstein-Barr virus (EBV) DNA was detected in all six AILD type cases by PCR amplifying the sequence located in the internal repeat I, and confirmed by Southern blot hybridization, using a BamHI-W fragment as a probe. Detection of the EBV genome occurred more frequently as compared with other types of lymphoid disorders. Furthermore, EBV determined nuclear antigen (EBNA) was detected in UCHL-1 (CD45RO, pan-T cell marker) positive cells by immunostaining. These results suggest that a significant number of AILD type cases are T cell origin lymphomas and EBV infection may be relevant to the biological features of this type of lymphoma.

Adolescent↗