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Biomedical subjects

M Furukawa

Publications and source records attributed to M Furukawa.

At least 109 records · Page 6Linked to original sources
PubMed1999

Decrease in the prevalence of IL-4-producing CD4+ T cells in patients with advanced stage of primary biliary cirrhosis.

OBJECTIVE: To elucidate the precise immunological features in primary biliary cirrhosis (PBC), we examined the relative prevalence of CD4+ T cells in either symptomatic PBC (sPBC) or asymptomatic PBC patients (aPBC), and furthermore, these results were compared with their histological features. METHODS: Cytokine synthesis of peripheral blood mononuclear cells obtained from 24 PBC patients (9 sPBC and 15 aPBC) were examined by intracellular staining method. The relative prevalence of three distinct CD4+ T cells, gamma-interferon (IFN-gamma)-producing cells (Th1), interleukin-4 (IL-4)-producing cells (Th2), and the cells producing both IL-4 and IFN-gamma (Th0), was analyzed by FACScan and compared with those of closely age-matched healthy and disease controls. RESULTS: The results demonstrated that although a significant difference was not observed in the prevalence of Th1 or Th0, a remarkable difference was observed in the prevalence of Th2 (1.2+/-0.7 in sPBC, 4.1+/-1.3 in healthy subjects, 4.1+/-2.1 in aPBC, 3.4+/-1.3 in chronic hepatitis C, and 3.6+/-2.3 in cirrhosis secondary to CH-C; p < 0.05 for sPBC vs all others). Histological examination of these patients showed that all aPBC patients belonged to relatively early stage (stage I-II) and 7 of 8 sPBC patients belonged to late stage (stage III-IV). Thus, our results suggest that, mainly as a result of the decline of Th2, a predominance of Th1 may exist in advanced stage PBC. CONCLUSIONS: The present results demonstrated that a slight elevation of Th1 prevalence, as well as a significant decline of Th2 prevalence, was observed in peripheral blood of advanced stage PBC.

Adult↗
PubMed1999

Matrix metalloproteinase 9 expression is induced by Epstein-Barr virus latent membrane protein 1 C-terminal activation regions 1 and 2.

Nasopharyngeal carcinoma (NPC), which is closely associated with the Epstein-Barr virus (EBV), is a highly metastatic malignant tumor. An important activity in tumor invasion and metastasis is that of the 92-kDa type IV collagenase or gelatinase, matrix metalloproteinase 9 (MMP-9), which mediates the degradation of the basement membrane and extracellular matrix. The expression of MMP-9 has been shown to be enhanced by the EBV oncoprotein, latent membrane protein 1 (LMP-1). LMP-1, which is expressed in NPC, has two essential signaling domains within the carboxy terminus, termed C-terminal activation regions 1 (CTAR-1) and CTAR-2. This study reveals that either signaling domain can activate the MMP-9 promoter and induce MMP-9 activity; however, LMP-1 deletion mutants lacking either CTAR-1 or CTAR-2 had a decreased ability to induce MMP-9 expression. The deletion of both activation regions completely abolished the induction of MMP-9 activity, while the cotransfection of both the CTAR-1 and CTAR-2 deletion mutants restored MMP-9 activity to levels produced by wild-type LMP-1. The NF-kappaB and activator protein 1 (AP-1) binding sites in the MMP-9 promoter were essential for the activation of MMP-9 gene expression by both CTAR-1 and CTAR-2. The induction of MMP-9 expression by LMP-1 and both CTAR-1 and CTAR-2 mutants was blocked by the overexpression of IkappaB. The tumor necrosis factor receptor-associated factor (TRAF) pathway also contributed to the activation of the MMP-9 promoter as shown by the use of TRAF-2 and TRAF-3 dominant-negative constructs. These data indicate that the activation of both the NF-kappaB and AP-1 pathways by LMP-1, CTAR-1, and CTAR-2 is necessary for the activation of MMP-9 expression. In NPC, LMP-1 may contribute to invasiveness and metastasis through the induction of MMP-9 transcription and enzymatic activity.

Binding Sites↗
PubMed1999

Infection of human respiratory submucosal glands with rhinovirus: effects on cytokine and ICAM-1 production.

To further understand the early biochemical events that occur in infected surface epithelium, we developed for the first time a model in which a respiratory submucosal gland cell population can be infected with rhinovirus (RV). Viral infection was confirmed by demonstrating with PCR that viral titers in supernatants and lysates from infected cells increased with time. Infection by RV14 upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) mRNA, the major RV receptor, on submucosal gland cells, and it increased production of interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor in supernatants. Antibodies to ICAM-1 inhibited RV infection of submucosal gland cells and decreased the production of cytokines after RV infection. Both IL-1alpha and IL-1beta upregulated ICAM-1 mRNA expression and increased susceptibility to RV infection, whereas other cytokines failed to alter ICAM-1 mRNA expression. Furthermore, neutralizing antibodies to IL-1alpha and IL-1beta significantly decreased the viral titers in supernatants and ICAM-1 mRNA expression after RV infection, but a neutralizing antibody to tumor necrosis factor-alpha was without effect. These findings suggest that respiratory submucosal gland cells play an important role in the initial stages of inflammation and provide useful insights into the pathogenesis of RV infection.

Adult↗
PubMed1999

Effect of caffeine on ibuprofen-induced gastric mucosal damage in rats.

During investigations on the effect of caffeine on ibuprofen-induced gastric mucosal lesions in rats, we have found that caffeine (p.o.) inhibits the development of ibuprofen-induced gastric lesions in a dose-dependent manner (ED50 18.4 mg kg(-1)). To investigate this protective effect of caffeine, we have studied the effect of caffeine on HCl-ethanol-induced gastric mucosal lesions with or without indomethacin pretreatment. Caffeine inhibited the development of HCl-ethanol-induced gastric lesions with and without indomethacin pretreatment. These results indicate that caffeine did not act as a mild irritant but, on the contrary, had protective effects. We measured the gastric mucosal prostaglandin E2 (PGE2) concentrations and gastric mucosal blood flow, as representative protective factors for gastric mucosa. Caffeine did not affect the gastric mucosal PGE2 concentrations 4h after administration of ibuprofen. However, topical administration of caffeine resulted in an increase in gastric mucosal blood flow, as measured by laser Doppler flowmetry. We investigated the gastric acid secretion and gastric mucosal myeloperoxidase activity as representative aggressive factors for gastric mucosa. When caffeine was administered intraduodenally in pylorus-ligated rats, gastric acid secretion decreased in a dose-dependent manner, with an ED50 of 44.9 mg kg(-1). Caffeine decreased ibuprofen-induced gastric myeloperoxidase activity in a dose-dependent manner, with an ED50 of 9.1 mg kg(-1). These findings indicate that caffeine, at least in rats, may inhibit the development of acute gastric mucosal injury. The mechanisms underlying the protective actions of caffeine are unclear, but may be related in part to an increase in gastric mucosal blood flow and suppression of neutrophil activation.

Administration, Oral↗
PubMed1999

Topology effect for DNA structure of cisplatin: topological transformation of cisplatin-closed circular DNA adducts by DNA topoisomerase I.

The reaction of cis-Pt(NH3)2Cl2(cis-DDP)-closed circular DNA adducts with DNA topoisomerse I(topo I) were studied by electron microscopy. We identified unique topoisomers such as a singly-linked catenane (2(1)2), trefoil (3(1), and dimetric catenane (2(1)2), etc., by analysis with electron micrographs. These unique recombination products resulted from cis-DDP-intra-twisting looped DNA adducts by DNA topo I, and the products could be explained a new mechanism based on an odd-even number rule. Our results suggest a new model on the working mechanisms for DNA topology of cis-DDP which enhances the recombination of DNA. Based on our results, we propose the topological idea that the yields of a mini closed circular DNA and pseudo trefoil DNA, etc., can be expected by reaction of cis-DDP-DNA-histone complexes with DNA topo I in the body.

Antineoplastic Agents↗
PubMed1999

A three-month repeated oral administration study of a low viscosity grade of hydroxypropyl methylcellulose in rats.

The toxicity of the lowest viscosity grade of hydroxypropyl methylcellulose (HPMC) that is currently commercially available was investigated by means of a three-month repeated oral administration study in male and female Crj:CD (SD) IGS rats at doses of 505, 1,020 and 2,100 mg/kg/day. Body weights of males and females in the 2,100 mg/kg group were lower than those of the control group on and after day 28 of administration, but the differences were not statistically significant. The degree of suppression of body weight gain in males was higher than that in females. This tendency was similar to the results in other toxicity studies of HPMC that have been reported. Males in the 2,100 mg/kg group showed a tendency (not significant) for decreased food consumption and urine volume. Examinations of general signs, hematology, blood chemistry, ophthalmology, absolute and relative organ weights, autopsy and histopathology revealed only a few, apparently coincidental, statistically significant differences from the control, and no evidence of any dose-dependent changes was found. It was concluded that the lowest viscosity grade of HPMC showed extremely low toxicity under the conditions of this study, as has been found for higher viscosity grades.

Administration, Oral↗
PubMed1999

[Glutathione and cisplatin resistance in head and neck cancer].

UNLABELLED: Since glutathione is considered to be an important mediator of cancer cell resistance to cisplatin-based chemotherapy, we investigated glutathione in head and neck cancer by both laboratory and clinical investigations. MATERIALS AND METHODS: Intracellular glutathione concentration was measured in 7 different cell lines that originated from head and neck cancer and was correlated to their IC50 to cisplatin. Expression of gamma-glutamyl cysteine (gamma-GCS) mRNA was assessed by in situ hybridization and gamma-glutamyl transpeptidase (GGT) expression was assessed with immnunohistochemistry of 56 biopsy specimens from 51 clinical cases. Both these enzymes are important for maintenance of intracellular glutathione concentration. RESULTS: Intracellular glutathione concentration was strongly correlated with cisplatin IC50 (R2 = 0.814, P = 0.0012), suggesting that glutathione plays a major role in cisplatin resistance in head and neck cancer. High gamma-GCS expression was observed in 27 out of 47 specimens (57%), but the response rate to chemotherapy (63%) in the high expression group was not significantly different to the low expression group (P = 0.20). High GGT expression was observed in 32 out of 53 specimens (60%), but the response rate in the high GGT group was not significantly different to that of the GGT group. CONCLUSION: Although intracellular glutathione plays an important role in resistance to cisplatin in head and cancer cell lines, we failed to prove that two enzymes that contribute to the maintenance of intracellular glutathione concentration are predictive factors for the response to cisplatin-based chemotherapy. Since clinical cases are further complicated by interactions of the immune system, involvement of a variety of genes related to oncogenesis, and accompanying drugs such as 5FU, it is very difficult to determine a single factor to predict the response to cisplatin. More precise analysis is necessary to determine how head and neck cancer resists cisplatin.

Carcinoma, Squamous Cell↗
PubMed1999

Structural and functional analysis of the control region of the human DNA topoisomerase II alpha gene in drug-resistant cells.

We have previously shown that the DNA topoisomerase II alpha (topo II alpha) gene is down-regulated in VP16/VM26-resistant cells at the transcriptional level. To determine the DNA elements responsible for down-regulation, the transcriptional activities of luciferase reporter constructs containing various lengths of the promoter sequences were investigated by transient transfection of two resistant cell lines, KB/VP2 and KB/VM4. The transcriptional activities of the full-length promoter (-295 to +85) and of three deletion constructs (-197, -154 and -74 to +85) were significantly down-regulated in resistant cells. In contrast, the transcriptional activity of the minimal promoter (-20 to +85) in resistant cells was similar to that in parental KB cells. Furthermore, introduction of a mutation in ICE1 abolished the down-regulation of the topo II alpha promoter activity in drug-resistant cells. In vivo footprinting analysis of topo II alpha gene promoter revealed several specific protein-binding sites, a GC box, ICE1, ICE2 and ICE3. In vivo footprinting analysis also identified a cluster of hypersensitive sites. However, there was no marked difference in protein-binding sites between parental and resistant cells. To confirm our previous results, we have established the VP16-resistant cell lines T12-VP1 and T12-VP2 from T12 cells derived from human bladder cancer T24 cells stably transfected with the chloramphenicol acetyltransferase reporter gene driven by the topo II alpha gene promoter. The expression to topo II alpha was down-regulated in both cell lines. We also found that CAT gene expression was significantly decreased to one-fifth of that in T12 parental cells. These results suggest that the expression of the topo II alpha gene requires the binding of multiple factors to the core promoter and is down-regulated at the transcriptional level, probably through binding of a negative factor to ICE1 in drug-resistant cells.

Antigens, Neoplasm↗
PubMed1998

Isolation of a novel human canalicular multispecific organic anion transporter, cMOAT2/MRP3, and its expression in cisplatin-resistant cancer cells with decreased ATP-dependent drug transport.

The human multidrug resistance protein (MRP) gene encodes a membrane protein involved in the ATP-dependent transport of hydrophobic compounds. We previously isolated a canalicular multispecific organic anion transporter, cMOAT1/MRP2, that belongs to the ATP binding cassette (ABC) superfamily, which is specifically expressed in liver, and cMOAT1/MRP2 is responsible for the defects in hyperbilirubinemia II/Dubin-Johnson syndrome. In this study, we isolated a new cDNA of the ABC superfamily designated cMOAT2/MRP3 that is homologous to human MRP1 and cMOAT1/MRP2: cMOAT2/MRP3 is 56% identical to MRP1 and 45% identical to cMOAT1/MRP2, respectively. Fluorescence in situ hybridization demonstrated the chromosomal locus of this gene on chromosome 17q22. The human cMOAT2 cDNA hybridized to a 6.5-kb mRNA that was mainly expressed in liver and to a lesser extent in colon, small intestine, and prostate. The cMOAT2/MRP3 gene was not overexpressed in cisplatin-resistant cell lines with increased ATP-dependent transport of cisplatin over their parental counterparts derived from human head and neck cancer and human prostatic cancer cell lines. The human cMOAT2/MRP3, a novel member of the ABC superfamily, may function as a membrane transporter in liver, colon, and prostate.

Adenosine Triphosphate↗
PubMed1998

The role of an inverted CCAAT element in transcriptional activation of the human DNA topoisomerase IIalpha gene by heat shock.

Expression of the DNA topoisomerase IIalpha (topoIIalpha) gene is highly sensitive to various environmental stimuli including heat shock. The amount of topoIIalpha mRNA was increased 1.5-3-fold 6-24 h after exposure of T24 human urinary bladder cancer cells to heat shock stress at 43 degreesC for 1 h. The effect of heat shock on the transcriptional activity of the human topoIIalpha gene promoter was investigated by transient transfection of T24 cells with luciferase reporter plasmids containing various lengths of the promoter sequence. The transcriptional activity of the full-length promoter (nucleotides (nt) -295 to +85) and of three deletion constructs (nt -197 to +85, -154 to +85, and -74 to +85) was increased approximately 3-fold 24 h after heat shock stress. In contrast, the transcriptional activity of the minimal promoter (nt -20 to +85), which lacks the first inverted CCAAT element (ICE1), the GC box, and the heat shock element located between nt -74 and -21, was not increased by heat shock. Furthermore, the transcriptional activity of promoter constructs containing mutations in the GC box or heat shock element, but not that of a construct containing mutations in ICE1, was significantly increased by heat shock. Electrophoretic mobility shift assays revealed reduced binding of a nuclear factor to an oligonucleotide containing ICE1 when nuclear extracts were derived from cells cultured for 3-24 h after heat shock. No such change in factor binding was apparent with an oligonucleotide containing the heat shock element of the topoIIalpha gene promoter. Finally, in vivo footprint analysis of the topoIIalpha gene promoter revealed that two G residues of ICE1 that were protected in control cells became sensitive to dimethyl sulfate modification after heat shock. These results suggest that transcriptional activation of the topoIIalpha gene by heat shock requires the release of a negative regulatory factor from ICE1.

Antigens, Neoplasm↗
PubMed1998

The expression of matrix metalloproteinase 9 is enhanced by Epstein-Barr virus latent membrane protein 1.

Matrix metalloproteinases (MMPs) are frequently expressed in malignant tumor cells and are thought to play crucial roles in tumor invasion and metastasis. Here we report that expression of MMP9 is increased in Epstein-Barr virus (EBV)-infected type III latency lymphoma cell lines, but not in type I lines where latent viral gene expression is highly restricted. Type III cell lines express abundant EBV latent membrane protein 1 (LMP1), the principal EBV oncoprotein, as well as the other latency proteins including the transcriptional factor, EBV nuclear antigen 2, which is also required for cell immortalization. Transfection of an LMP1 expression plasmid in the C33A cell line increased MMP9 expression, whereas overexpression of EBV nuclear antigen 2 did not. Three motifs, homologous to the binding sites of NF-kappaB, SP-1, and AP-1 proteins, contribute to induction of the MMP9 promoter by 12-O-tetradecanoyl-phorbol-13-acetate and tumor necrosis factor alpha. Here we report that binding sites for NF-kappaB, SP-1, and AP-1 also contribute to induction of the MMP9 promoter by the viral protein, LMP1, mainly through the NF-kappaB and, to a lesser extent, the SP-1 and AP-1 sites. Moreover the AP-1 binding site is essential in that mutation of it abolished reporter gene induction by LMP1. The enhancement of MMP9 expression was blocked by cotransfection of an IkappaB expression plasmid. Thus in addition to its transforming properties, the oncoprotein LMP1 may contribute to invasiveness and metastasis of EBV-associated tumors such as nasopharyngeal carcinoma.

Binding Sites↗
PubMed1998

Retrograde transport of nerve growth factor from olfactory bulb to olfactory epithelium.

NGF is produced in the olfactory bulb and transported from the bulb to cholinergic neurons in the horizontal limb of the diagonal band. Although the expression of NGF receptors has been reported in olfactory epithelial cells, no correlation between NGF and olfactory epithelial cells has been found. This study aimed to define whether or not retrograde transport of NGF occurs in the olfactory neural system using the method of radioluminography. 125I-labeled NGF injected into the olfactory bulb was taken up and transported to the olfactory epithelium 18 h after injection. This finding suggests that bulbar NGF may act as a neurotrophic factor in olfactory epithelial cells.

Animals↗
PubMed1998

Substance P- and calcitonin gene-related peptide-containing nerve fibers in the nasal mucosa of chronically hypoxic rats.

The distribution of substance P-immunoreactive and calcitonin gene-related peptide-immunoreactive nerve fibers in the nasal mucosa was compared between normoxic and chronically hypoxic rats (10% O2 and 3.0-4.0% CO2 for 3 months). In the normoxic nasal mucosa, substance P- and calcitonin gene-related peptide-immunoreactive nerve fibers were found within and under the epithelium and around the glands and blood vessels in the lamina propria. These immunoreactive fibers have many varicosities. In the chronically hypoxic nasal mucosa, the relative density of intra- and subepithelial substance P-immunoreactive and calcitonin gene-related peptide-immunoreactive fibers and those in the lamina propria was higher than in normoxic mucosa. The length of substance P-positive fibers within the chronically hypoxic olfactory and respiratory epithelium was 1.66 and 2.45 times higher than within the normoxic epithelium, respectively. The length of calcitonin gene-related peptide-immunostained fibers within the chronically hypoxic olfactory and respiratory epithelium was 1.56 and 1.84 times higher, respectively. Because substance P and calcitonin gene-related peptide are the predominant signal peptides of primary sensory neurons, the increased number of these fibers may represent enhanced sensory mechanisms in the hypoxic nasal mucosa. In addition, considered together with the findings in chronically hypoxic tracheal mucosa, the increased density of intraepithelial fibers containing substance P and calcitonin gene-related peptide suggests that this is a predominant feature of hypoxic adaptation throughout the upper and lower respiratory tracts.

Animals↗
PubMed1998

Squamous cell carcinoma of the nasal septum with Wegener's granulomatosis treated with cyclophosphamide and corticosteroids.

Well differentiated squamous cell carcinoma of the nasal septum developed in a 55-year old man with Wegener's granulomatosis. It is suggested that the malignancy was induced by immunosuppressive state from an increased and prolonged use of cyclophosphamide and corticosteroids. Although the efficacy of the therapeutic concept using cyclophosphamide and corticosteroids is well established, there have been some few reports that cyclophosphamide could be implicated in the genesis of malignancies. The pathophysiology of Wegener's granulomatosis should be better understood, and effective and less toxic alternative protocol should be established.

Adrenal Cortex Hormones↗
PubMed1998

A2 adenosine receptors in Mongolian gerbil middle ear epithelium and their regulation of Cl- secretion.

The present study investigates the effects of adenosine and its analogues on Cl- secretion in primary cultures of gerbil middle ear epithelium. Short-circuit current (Isc), an index of transepithelial active transport, was measured on the same cells cultured on porous filters. Baseline Isc and transepithelial resistance were 27.0 +/- 0.7 microA cm-2 and 275 +/- 7 omega cm2, respectively (n = 178). Extracellular adenosine and its analogues elicited a sustained increase in Isc when added to apical or basolateral surfaces. Both the A2A selective agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamido adenosine and the A2A/A2B nonselective agonist 5'-(N-ethyl-carboxamido)adenosine (NECA) increased Isc, but NECA was more effective than CGS21680. A1 selective antagonist 8-cyclopentyl-1,3-dipropylxanthine did not reduce NECA-induced Isc. These results suggest the presence of both A2A and A2B receptors. NECA did not stimulate a rise in the intracellular Ca2+ concentration ([Ca2+]i) in single middle ear epithelial cells cultured on glass coverslips. Dibutyryl cAMP (dbcAMP) induced an initial transient increase in Isc followed by the sustained plateau. Addition of dbcAMP also caused a transient increase in [Ca2+]i. The protein kinase A inhibitor, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide, greatly reduced the increase in the Isc responses to NECA. 1,2-Bis-(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid-acetoxymethyl ester influenced neither the NECA-induced increase in Isc nor the dbcAMP-induced sustained phase of Isc, but greatly inhibited the dbcAMP-induced transient increase in Isc. Glibenclamide, a cystic fibrosis transmembrane conductance regulator (CFTR) channel inhibitor, reduced the NECA-induced Isc. These results indicate that extracellular adenosine and its analogues activate the cAMP-protein kinase A system, but not intracellular Ca(2+)-dependent mechanisms, leading to Cl- secretion, possibly through the CFTR Cl- channels in the cultured gerbil middle ear epithelium.

Adenosine↗
PubMed1998

Immunohistochemical localisation of regulatory neuropeptides in human circumvallate papillae.

The occurrence and distribution of neuropeptide-containing nerve fibres in the human circumvallate papillae were examined by the peroxidase-antiperoxidase immunolocalisation method using surgical specimens that had not been subjected to radiotherapy, and the abundance of neuropeptide-containing fibres was expressed as the percentage of total nerve fibres demonstrated by protein gene product (PGP) 9.5 immunoreactivity for a quantitative representation of these peptidergic fibres. Substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive (IR) nerve fibres were densely distributed in the connective tissue core of the circumvallate papillae, and some SP and CGRP-IR fibres were associated with the taste buds. A moderate number of vasoactive intestinal polypeptide (VIP)-IR fibres and a few galanin (GAL)-IR fibres were also seen in the connective tissue core and subepithelial layer. There were, however, no VIP-IR or GAL-IR fibres associated with the taste buds. Neuropeptide Y (NPY)-IR fibres were few and were associated with the blood vessels. Within the epithelium of the circumvallate papillae, no peptidergic fibres were found, although a number of PGP 9.5-IR fibres were detected. The abundance of SP, CGRP, VIP, and GAL-IR fibres expressed as the percentage of total PGP 9.5 IR fibres was 25.35+/-3.45%, 22.18+/-3.26%, 10.23+/-1.18%, and 4.12+/-1.05%, respectively. The percentage of NPY-IR fibres was below 3%. In a deeper layer of the papillae, a few VIP, GAL, and NPY-IR ganglion cells were found, and VIP immunoreactivity was detected in a few cells of the taste buds. There was no somatostatin, leucine enkephalin, or methionine enkephalin immunoreactivity in the circumvallate papillae. These results suggest that the dense SP and CGRP-IR fibres within the connective tissue core of the human circumvallate papillae may be involved in the deep sensation of the tongue.

Adult↗