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Biomedical subjects

J Tanaka

Publications and source records attributed to J Tanaka.

At least 325 records · Page 18Linked to original sources
PubMed1996

Selective activation of the proto-oncogene c-jun promoter by the transforming protein v-Rel.

The transcription factor v-Rel is a transforming protein of the reticuloendotheliosis virus. We found that v-Rel activates the promoter of the proto-oncogene c-jun. Two elements in the c-jun promoter were required for the activation by v-Rel. One was a kB-site (v-Rel binding site), and the other was a c-jun promoter region between -52 and +148 (c-jun promoter (-52/+148)). Two promoters with the kB-site(s), those of human immunodeficiency virus (HIV) and SV40, were not activated by v-Rel, but their kB-sites were activated when introduced upstream of the c-jun promoter (-52/+148). Thus, the c-jun promoter (-52/+148) had information for the selective activation of the c-jun promoter by v-Rel. v-Rel bound to the c-jun kB-site with the higher affinity than c-Rel, thereby activating the c-jun promoter more efficiently than c-Rel. Moreover, the activity of v-Rel mutants upon the c-jun promoter correlates with their transforming activity. Thus, the c-jun promoter activation by v-Rel may play a role in the transformation caused by v-Rel.

Amino Acid Sequence↗
PubMed1996

Continuous HGF supply from HGF-expressing fibroblasts transplanted into spleen prevents CCl4-induced acute liver injury in rats.

Hepatocyte growth factor (HGF), first identified as a potent mitogen for mature hepatocytes, has been reported to have various activities. We investigated protective effect of continuous HGF supply on carbon tetrachloride (CCl4)-induced acute liver injury in rats. We transfected immortalized but not tumorigenic rat fibroblasts (Rat-1) with an expression plasmid containing the human HGF cDNA and established several cell lines expressing HGF. The biological activity of HGF produced by these cell lines was confirmed by its mitogenic effect on rat hepatocytes in vitro. Either one of the high-HGF-producer cell lines or parental Rat-1 cell line was transplanted into a syngenic rat spleen. Twelve days after transplantation, each rat was intraperitoneally injected with CCl4 and sacrificed 48 h after CCl4 injection. In rats with continuous HGF supply significantly lower serum glutamic-pyruvic transaminase (GPT) level was observed compared to its marked elevation in control rats and the degree of hepatocyte damage was slight on histological analysis. These results indicate that continuous HGF supply effectively inhibits CCl4-induced acute liver injury and may suggest the possibility that this system would be useful on various liver diseases.

Alanine Transaminase↗
PubMed1996

Pathomechanism of cerebral hypoplasia in experimental toxoplasmosis in murine fetuses.

In order to elucidate the pathological mechanism of cerebral hypoplasia in congenital toxoplasmosis, fetal toxoplasmosis was induced by intraperitoneal injection of Toxoplasma gondii into five pregnant mice on embryonal Day 5 (E5). The maternal and fetal brains were examined histologically and immunohistochemically; six fetuses were examined on E16 and 21 on E18. T. gondii organisms were immunohistochemically detected in the maternal brains, placentas and the ventricular zone of the fetal cerebrum. In none of the fetal brains was any gross deformity observed, except for cerebral hypoplasia. On E16 and E18, the cerebral cortices were seen to consist of immature laminations, and the cells had less cytoplasm and rounder hyperchromatic nuclei than those in the control mice. The cerebral walls and the cortical layers, except in the ventricular zone, were thinner than in the controls (P < 0.01 in each case). On E18, the proliferating cell nuclear antigen immunolabeling index was higher, and the cytoplasm of more cells in the cortical plate was immunoreactive with anti-beta-tubulin antibody compared with control mice. Using an in situ end-labeling technique, apoptotic cells were not observed in the cortices in mice of both groups. It is suggested that the cerebral hypoplasia following Toxoplasma infection is related to delayed maturation.

Animals↗
PubMed1996

Microinjection of intact MAP-4 and fragments induces changes of the cytoskeleton in PtK2 cells.

The molecular cloning and sequencing of microtubule-associated protein (MAP)-4 identified microtubule-binding repeats near the C-terminus and a projection domain near the N-terminus. Although it is well known that MAP-4 stimulates the assembly of and stabilizes microtubules (MT) in vitro, the function of MAP-4 in vivo is still unclear. In this study, we examined the function of MAP-4 in the cytoskeleton both in vitro and in vivo. Intact MAP-4 was prepared from bovine adrenal cortex, and the truncated fragments of the N- and the C-terminal halves (named NR and PA4 fragments, respectively) were expressed in Escherichia coli and isolated. In vitro studies demonstrated that in a solution containing a physiological concentration of NaCl, intact MAP-4 and the PA4 fragment were bound to MT, but not to F-actin. The NR fragment was not bound to MT or to F-actin. We also examined the MT changes in PtK2 cells after they had been microinjected with intact MAP-4 and the truncated fragments of PA4 and NR. The injection of intact MAP-4 or PA4 into the cells induced an increase in the number of cytoplasmic MT, as well as MT bundling. The NR fragment did not affect the MT array. Injected MAP-4 and PA4 were associated with the increased MT. In addition, injection with MAP-4 and PA4 stabilized MT in relation to treatment with the MT-disrupting drug, nocodazole. These results indicated that intact MAP-4 and the PA4 fragment promoted MT assembly and stabilized MT, by binding to MT, in vivo as well as in vitro. Further, the injection of the PA4 fragment induced an increase in stress fibers. However, these proteins did not show any association with the stress fibers. Our results suggest that there is an indirect effect of MAP-4 on stress fibers rather than a direct interaction between MAP-4 and stress fibers.

Actins↗
PubMed1996

Effects of GM-CSF and ordinary supplements on the ramification of microglia in culture: a morphometrical study.

Microglia transform from ameboid to ramified cells during development and display an ameboid appearance again under certain pathological conditions. Some cytokines produced by astrocytes may be responsible for the microglial transformation. In the present study, we compared the effects of cytokines, granulocyte/macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), and interleukin-3 (IL-3) on the morphology of rat cultured microglia. For quantitative evaluation, we employed "transformation index" as calculated by (perimeter of cell)2/4 pi (cell area). GM-CSF facilitated the ramification of cultured rat microglia, which was effectively induced in a serum-free medium. However, M-CSF and IL-3 did not induce the ramification. A certain serum adhesion protein (possibly vitronectin) as well as other high molecular weight substances in fetal calf serum inhibited the GM-CSF-induced microglial ramification. Among ordinary supplements for a chemically defined medium, progesterone, insulin, and a high concentration of glucose suppressed the ramification. These findings suggest that GM-CSF may be involved in microglial ramification and that many kinds of supplements that are added to culture media profoundly affect the morphology of microglial cells.

Animals↗
PubMed1996

IL-8/NAP-1 is the major T-cell chemoattractant in synovial tissues of rheumatoid arthritis.

T-cell infiltration into synovium is a crucial process for rheumatoid arthritis (RA). To investigate the mechanism of T-cell infiltration, we studied T-cell attracting activity in synovial tissue extracts of RA or osteoarthritis (OA) whose synovium lacks T-cell accumulation. RA extracts attracted twofold more T cells than OA extracts. By gel filtration column chromatography the activity of RA extracts was separated into two peaks; one was eluted at the 67-kDa region and the other was at the 12-kDa region, while the latter was absent in OA extracts. The activity eluted at the 12-kDa region was absorbed mostly by an antibody against IL-8/NAP-1, a potent T-cell chemotactic factor. IL-8/NAP-1 concentrations in RA extracts were much higher than those in OA extracts and correlated to T-cell attracting activity eluted at the 12-kDa region. The checkerboard analysis revealed that the 67-kDa activity was chemokinetic but not chemotactic. These results suggest that IL-8/NAP-1 is the major T-cell chemoattractant in RA-synovium.

Aged↗
PubMed1996

Microglial ramification requires nondiffusible factors derived from astrocytes.

It is generally accepted that process-bearing microglial cells origina te from ameboid macrophage-like mesodermal cells. This transformation, often called ramification, accompanies down regulation of macrophage-like properties, but the mechanisms involved in ramification have not been clarified. We investigated factors to promote ramification in culture. Isolated ameboid microglial cells were seeded on living or paraformaldehyde-fixed astrocyte monolayers. About 80% of the cells ramified on the fixed astrocytes in astrocyte-conditioned medium as well as on the living astrocytes. In fresh culture medium, 50% of the cells on the fixed astrocytes ramified. On the other hand, ameboid cells rarely ramified on noncoated glass coverslips even in the conditioned medium. Ameboid cells cultured on extracellular matrices dervied from astrocytes ramified more than on those coated with plasma fibronectin or collagen type I. A synthetic peptide containing Arg-Gly-Asp sequence or a tyrosine kinase inhibitor genistein partially reversed the ramification induced on the fixed astrocyte monolayers. These results show that some nondiffusible factors derived from astrocytes are essential for microglial ramification. A part of the nondiffusible factors are present in the extracellular matrices, and the effects might be mediated by integrins. Some diffusible factors secreted by astrocytes seem to promote ramification, if the nondiffusible factors are present. The experiments using the fixed astrocyte monolayers may be useful to identify the diffusible factors responsibile for ramification.

Amino Acid Sequence↗
PubMed1996

Laparoscopically assisted resection of the lower rectum.

We report a new laparoscopic approach to the resection of the lower rectum which has been successfully used in the treatment of a patient with a small rectal carcinoid tumor. Under general anesthesia a pneumo-peritoneum was established with CO2 gas insufflation and the rectum was mobilized from the sacrum including division of the lateral ligaments under the direct view of the laparoscope. The bowel was divided between the sigmoid colon and the rectum using an endoscopic linear stapler, and the rectum was everted through the anal canal. The lower rectum was transected extracorporeally using a linear stapler and the rectal stump was then returned to the anatomical position. An anvil of a circular stapling device into the oral colon stump through a small skin incision on the left lower abdomen was introduced and the shaft of the device through the rectal stump via anus was inserted. The device was then re-approximated under laparoscopic view and fired. Our procedure described here is applicable to the lower rectal lesion as a minimally invasive, safe, and useful therapeutic tool.

Carcinoid Tumor↗
PubMed1996

Effects of cholecystokinin and carbachol on membrane fluidity in pancreatic acini.

The effects of pancreatic secretagogues on the membrane fluidity of pancreatic acini were investigated using 1-[4-(trimethylammonium)phenyl]-6-phenyl-1,3,5-hexatriene iodide as a probe. Two kinds of pancreatic secretagogues, one category of which induces acute pancreatitis (cholecystokinin and carbachol) and another which does not induce acute pancreatitis (bombesin, CCK-JMV-180, and secretin), as well as lecithin were used to investigate the effect of changes in membrane fluidity of acini. Our study revealed that the membrane fluidity of the pancreatic acini was unaffected by a physiological dose (10(-11) M) of cholecystokinin. However, stimulation with a supramaximal dose of cholecystokinin (10(-8) M) increased membrane fluidity markedly within 20 min. Membrane fluidity increased dose-dependently with increasing CCK stimulation. A supramaximal dose of cholecystokinin also induced bleb formation and increased LDH release. These phenomena were blocked by simultaneous incubation with CR1505 (Loxiglumide), a potent antagonist of peripheral cholecystokinin receptors. A supramaximal dose of carbachol (10(-3) M) also induced increases in the membrane fluidity. Pancreatic secretagogues that do not induce acute pancreatitis did not induce alterations in membrane fluidity. Lecithin increased both membrane fluidity and LDH release. These observations suggest that this increase in membrane fluidity of the pancreatic acini may be related to membrane alteration and to functional damage of the acini. These observations [correction of observation] can serve as a window to detect the development of acute pancreatitis at an early stage.

Animals↗
PubMed1996

Visualization of protein kinase activities in single cells by antibodies against phosphorylated vimentin and GFAP.

Vimentin and glial fibrillary acidic protein (GFAP) are intermediate filament proteins expressed in the cytoplasm of various types of cells. The head domains of these proteins are phosphorylated by various protein kinases. Site- and phosphorylation-specific antibodies which recognize a phosphorylated serine/threonine residue in the head domains and its flanking sequence provide a useful tool to monitor and visualize protein kinase activities in single cells.

Amino Acid Sequence↗
PubMed1996

Transformation of severe aplastic anemia into acute myeloblastic leukemia with monosomy 7.

A cytogenetically normal man with severe aplastic anemia was treated with granulocyte colonystimulating factor (G-CSF), erythropoietin (EPO), cyclosporin A, anti-thymocyte globulin, and interleukin-6 (IL-6), which resulted in a gradual improvement in his neutrophil count and hemoglobin level. After 2 years of the therapy, monosomy 7 was detected during cytogenetic analysis of his bone marrow, which evolved during a period of 5 months into acute myeloblastic leukemia. An in vitro proliferation assay of cytokine responses showed that leukemic blasts were sensitive only to G-CSF, and not to EPO or IL-6. Although allogeneic bone marrow transplantation from an HLA-matched unrelated donor was carried out in the non-remission stage, the patient died of systemic fungal infection on day 25, without any evidence of hematological engraftment. As long-term use of cytokines and immunomo-suppressants in patients with severe aplastic anemia may induce or hasten the onset of a malignant transformation, careful attention must be paid to clonal evolution. Due to the poor prognosis of secondary myelodysplasia and leukemia, allogeneic bone marrow transplantation for such patients must be carried out early in the course of the disease.

Adult↗
PubMed1996

HLA-DR antigen and interleukin-2 receptor expression on primary-cultured human hepatic macrophages in relation to liver cirrhosis and hepatitis virus infection.

We analyzed primary-cultured human hepatic macrophages (HHMphi) from 12 patients with non-cirrhotic and cirrhotic livers for cell surface expression of HLA-DR antigen and interleukin-2 receptor (IL-2R). Compared to the relatively abundant HLA-DR antigen, IL-2R expression was generally low. No significant difference was observed between HLA-DR antigen expression nor IL-2 receptor expression. HHMphi from patients with serum hepatitis viral markers, however, expressed significantly more HLA-DR antigen than did HHMphi of patients without viral markers, which suggest a possible role of HHMphi as antigen-presenting cells (APC) in viral hepatitis. This direct, quantitative measurement of cell surface molecule expression on hepatic macrophages of human may provide an important clue to the pathophysiology of human liver disorders.

Aged↗
PubMed1996

Ultrasound biomicroscopic study of ciliary body thickness after topical application of pharmacologic agents.

PURPOSE: To examine the changes in ciliary body thickness after topical application of pilocarpine, cyclopentolate hydrochloride, and PhXA41, a prostaglandin F2alpha analog. METHOD: We used high-frequency Humphrey UBM840 ultrasound biomicroscope to examine 36 healthy young Japanese subjects. RESULTS: The mean ciliary body thickness increased from 0.67 +/- 0.07 mm to 0.073 +/- 0.08 mm (P < .01) after application of 2% pilocarpine; 1% cyclopentolate hydrochloride and 0.005% PhXA41 decreased the mean ciliary body thickness from 0.75 +/- 0.07 mm to 0.69 +/- 0.05 mm (P < .05) and from 0.78 +/- 0.06 mm to 0.75 +/- 0.06 mm (P < .01), respectively. CONCLUSIONS: Our ultrasound study clearly indicates that pilocarpine increased comparative thickness of the ciliary body by 8.3%, whereas PhXA41 decreased comparative thickness by 3.3% in a manner similar to cyclopentolate hydrochloride.

Administration, Topical↗
PubMed1996

Identification of carcinoembryonic antigen mRNA in circulating peripheral blood of pancreatic carcinoma and gastric carcinoma patients.

To detect adenocarcinoma cells in the circulating peripheral blood, we "analyzed the presence of carcinoembryonic antigen (CEA) mRNA in the peripheral blood obtained from patients with pancreatic carcinoma (PC) or with gastric carcinoma (GC) and also, as controls, from pancreatitis or gastritis patients without carcinomas, a gastric lymphoma patient and four healthy volunteers. Because of the small number of carcinoma cells expected in the peripheral blood, the analysis was performed by the reverse transcription followed by an original two-step polymerase chain reaction. By this sensitive method, 3 of 9 PC patients and 2 of 9 GC patients were positive for CEA mRNA. Except for 1 highly advanced PC patient, 3 of 4 CEA mRNA-positive patients developed recurrence after curative resection or liver metastasis after palliative operation within 9 months after the analysis. None of the control patients was positive for CEA mRNA in the peripheral blood. The results suggest that our sensitive RT-PCR method for detecting CEA mRNA in the peripheral blood is practically useful to find the hematogenous spreading of adenocarcinoma cells.

Aged↗
PubMed1996

Relationship of substance P and gliosis in medulla oblongata in neonatal sudden infant death syndrome.

Substance P and glial fibrillary acidic protein (GFAP) immunohistochemistry was applied to the medulla of neonatal infants who died of sudden infant death syndrome (SIDS). A quantitative analysis of cells demonstrating immunoreactivity to GFAP and substance P in 15 neonatal SIDS cases revealed increased GFAP immunoreactivity in the reticular formation, the dorsal vagal nucleus, and the solitary nucleus and an increase in substance P immunoreactivity in the spinal trigeminal nucleus and the solitary nucleus as compared with that in age-matched controls. GFAP immunopositivity suggests astrogliosis which implies a pathologic insult to neurons in the area of astrogliosis. The failure of neurons in these sites to show enhanced substance P immunopositivity may indirectly indicate altered neurons. Further study of prenatal events may be of importance in clarifying the pathogenesis of neonatal SIDS.

Chi-Square Distribution↗
PubMed1996

A hydrophilic peptide comprising 18 amino acid residues of the prosaposin sequence has neurotrophic activity in vitro and in vivo.

Prosaposin, a 517-amino-acid glycoprotein, not only acts as the precursor of saposin A, B, C, and D but also possesses neurotrophic activity to rescue hippocampal CA1 neurons from ischemic damage in vivo and to promote neurite extension of neuroblastoma cells in vitro. Recently, the trophic activity of prosaposin on human neuroblastoma cells has been shown to reside in the NH2-terminal hydrophilic sequence (LIDNNRTEEILY) of the human saposin C. Here we show that prosaposin, saposin C, and a peptide comprising the 18-amino-acid sequence (18-mer peptide; LSELIINNATEELLIKGL) located in the NH2-terminal hydrophilic sequence of the rat saposin C-domain promoted survival and neurite outgrowth of cultured rat hippocampal neurons in a dose-dependent manner. Moreover, infusion for 7 days of the 18-mer peptide into the lateral ventricle of gerbils, starting either 2 h before or immediately after 3 min of forebrain ischemia, protected ischemia-induced learning disability and hippocampal CA1 neuronal loss. Thus, we ascribe the in vitro and in vivo trophic actions of prosaposin on hippocampal neurons to the linear 18-mer sequence and raise the possibility that this peptide can be used as an agent for the treatment of forebrain ischemic damage.

Amino Acid Sequence↗
PubMed1996

Chemical mediators released by primary-cultured human hepatic macrophages in patients with and without cirrhosis: a study in tumor-bearing patients.

To elucidate the possible role of chemical mediators in modulating the host-defense activity of patients with cirrhosis, primary-cultured human hepatic macrophages (HHMphi) were obtained from cirrhotic and noncirrhotic patients who received liver resections because of the presence of malignant liver tumors. The cirrhotic and noncirrhotic groups consisted of patients with similar malignancies: noncirrhotic patients had normal liver function and normal liver histology for nontumorous portions. The cultured HHMphi were analyzed for their ability to release chemical mediators with specific activities in the host defense system. Dose-dependent increases in superoxide release, interleukin-1 (IL-1) release, and, within a relatively narrow range, prostaglandin-E2 (PGE2) release were observed in opsonized zymosan (oz)-stimulated HHMphi derived from both cirrhotic and noncirrhotic patients. The release of O2- and PGE2 from HHMphi derived from cirrhotic patients was significantly less than HHMphi derived from noncirrhotic patients, whereas the release of IL-1 was significantly greater. Although, because of the limited sample availability, only tumor-bearing patients were studied, the mediator-releasing ability of HHMphi derived from cirrhotic patients was significantly different from the ability of HHMphi derived from noncirrhotic patients with similar malignancies. This phenomenon may be related to altered host defenses in patients with cirrhosis.

Adjuvants, Immunologic↗