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Biomedical subjects

K Furuta

Publications and source records attributed to K Furuta.

At least 19 recordsLinked to original sources
PubMed2001

Expression of the lysosome-associated membrane proteins in myopathies with rimmed vacuoles.

Lysosome-associated membrane proteins (LAMPs) are structural glycoproteins located on the lysosomal membrane and are thought to have an important role in protein degradation. Increased lysosomal activity is associated with the formation of rimmed vacuoles, which are observed in various muscle disorders such as inclusion body myositis (IBM) and distal myopathy with rimmed vacuole (DMRV). In the present study, we examined LAMP-1 and LAMP-2 in biopsied muscle specimens from four cases of sporadic IBM and two of DMRV, as well as six of myopathies without rimmed vacuoles. In all cases of IBM and DMRV, immunohistochemistry showed accumulation of LAMPs in the rimmed vacuoles and the subsarcolemmal portion of the vacuolated fibers. Immunoreactivities of LAMPs in the vacuolated fibers were often associated with those of cathepsin D; however, cathepsin D was not expressed on some LAMP-positive fibers. Further, atrophic muscle fibers were sometimes positive for LAMPs expression. These findings were more prominent in LAMP-2 than in LAMP-1. Thus, LAMP-2 may play an important role in the increased protein degradation in diseased muscle fibers. The increased expression of LAMPs in the vacuolated muscle fibers may be associated with the formation of rimmed vacuoles in IBM and DMRV.

Adult↗
PubMed2001

Expression of lysosome-associated membrane proteins in human colorectal neoplasms and inflammatory diseases.

The lysosome-associated membrane proteins (LAMPs)-1 and -2 are major constituents of the lysosomal membrane. These molecules are known to be among the most glycosylated proteins of several types of cells and cancer cells, and their expression in cancer cells is marked by a distinct difference in the structures of the oligosaccharides as compared to nonmalignant cells. We analyzed by immunohistochemistry the intensity and distribution of LAMP-1 and LAMP-2 in 9 human colorectal cancer cases and in 16 control cases, including inflammatory diseases (diverticulitis, ulcerative colitis, and Crohn's disease). LAMP proteins were expressed more intensely in the epithelium of colorectal neoplasms than in normal mucosa (P < 0.05), and no significant differences were found between adenoma and cancer cells (P > 0.05) in the same tissue section. Further, in sites of inactive inflammatory diseases and nonneoplastic areas in cancer specimens, no significant increases in epithelial LAMP proteins were observed, even in the proliferative zone of the lower crypt epithelium. Northern blot analysis showed increased expression of LAMP-1 and LAMP-2A in two of three colorectal cancers examined and increased LAMP-2B in all three cancers. Our findings suggest that LAMPs are related to neoplastic progression, but there is no direct association between the expression of LAMP molecules and cell proliferation.

Adenocarcinoma↗
PubMed2001

Neurotrophic actions of novel compounds designed from cyclopentenone prostaglandins.

Previously we found that some cyclopentenone prostaglandin derivatives promoted neurite outgrowth from PC12 cells and dorsal root ganglia explants in the presence of nerve growth factor; and so we referred to them as neurite outgrowth-promoting prostaglandins (NEPPs). In this study, NEPPs protected HT22 cells against oxidative glutamate toxicity. NEPP6, one of the most effective promoters of neurite outgrowth in PC12 cells, protected the cells most potently among NEPPs 1--10. Several derivatives, NEPPs 11--19, were newly synthesized based on the chemical structure of NEPP6. NEPP11 had a more potent neuroprotective effect than NEPP6. NEPP11 also prevented the death of cortical neurons induced by various stimuli and reduced ischemic brain damage in mice. Biotinylated compounds of NEPPs were synthesized to investigate their cellular accumulation. NEPP6-biotin protected the cells and emitted potent signals from the cells. In contrast, biotinylated non-neuroprotective derivatives emitted much weaker signals. These results suggest that NEPPs are novel types of neurotrophic compounds characterized by their dual biological activities of promoting neurite outgrowth and preventing neuronal death and that their accumulation in the cells is closely associated with their neuroprotective actions.

Animals↗
PubMed2001

A mutation of the Wilson disease protein, ATP7B, is degraded in the proteasomes and forms protein aggregates.

BACKGROUND & AIMS: Wilson disease is a genetic disorder characterized by the accumulation of copper in the body as a result of a defect of copper excretion from hepatocytes. The intracellular localization of the Wilson disease gene product, ATP7B, was recently identified as the late endosomes. Various mutations have been documented in patients with Wilson disease. The clinical manifestations vary greatly among the patients; however, there is little information on the genotype-phenotype correlation. METHODS: We investigated the distribution of a common ATP7B mutant His1069Gln and a mutant Asp1270Ser by expressing the mutants tagged with green fluorescent protein in Huh7 and HEK293 cells. Intracellular organelles were visualized by fluorescence microscopy. RESULTS: Although the wild-type ATP7B and Asp1270Ser mutant localized in the late endosomes, His1069Gln mutant did not locate in the late endosomes and was degraded by the proteasomes in the cytoplasm. Furthermore, His1069Gln formed aggresomes composed of the degradates and intermediate filaments at the microtubule-organizing center. These aggresomes were similar to Mallory bodies on electron microscopy. CONCLUSIONS: The different protein properties of ATP7B mutants may explain the variety of clinical spectrums in patients with Wilson disease.

Acetylcysteine↗
PubMed2001

Antitumor activity, optimum administration method and pharmacokinetics of 13,14-dihydro-15-deoxy-deoxy-Delta7 -prostaglandin A1 methyl ester (TEI-9826) integrated in lipid microspheres (Lipo TEI-9826).

13,14-Dihydro-15-deoxy-Delta7-prostaglandin A1 methyl ester (TEI-9826), an antitumor prostaglandin analog, is a candidate for clinical trial. In the present study, we examined its biological stability in vitro, antitumor activity in vitro and in vivo, and pharmacokinetics. Although TEI-9826 was rapidly hydrolyzed to the carboxylic acid form (TOK-4528), TOK-4528 as well as Delta12-prostaglandin J2 (PGJ2) were found to be stable in rat, mouse and human serum in vitro. TEI-9826 exhibited nearly identical or greater potential antitumor activity compared to Delta12-PGJ2 and Delta7-PGA1 in vitro against Colon26 tumor cells. Further evaluation of TEI-9826 using the 38 human cancer cell lines panel and COMPARE analysis suggested that its mode of action is quite different from other anticancer agents that are currently used. TEI-9826 was integrated into lipid microspheres (Lipo TEI-9826) for dosing. Growth inhibition by Lipo TEI-9826 against Colon26 tumor inoculated s.c. in mice depended on administration route, i.e. at 80 mg/kg, no growth suppressive effect was observed for daily bolus i.v., but significant growth suppressive effect was observed for daily i.p., daily s.c. every other day s.c. and 4 times a day continuous (5 min) i.v. These tumor growth-suppressive effects were cytostatic and the tumor started to regrow at the end or a few days after the end of administration. The pharmacokinetic study suggested that maintaining the blood level of TEI-9826 and/or TOK-4528 was essential for their antitumor effects. These results show that continuous i.v. infusion might be the most suitable administration method of Lipo TEI-9826 for clinical trial.

Animals↗
PubMed2001

Gastrointestinal stromal tumor with a novel mutation of KIT proto-oncogene.

The majority of human gastrointestinal mesenchymal tumors are gastrointestinal stromal tumors (GISTs). Recent reports have shown the existence of gain-of-function mutations in the juxta-membrane domain of receptor tyrosine kinase (KIT) in GISTs. We present a 77-year-old woman with GIST diagnosed by positive immunostaining of cluster designation (CD) 34 and KIT. This case had a novel mutation at codon 576 located in the juxta-membrane domain of KIT. Our results indicate the importance of mutations in this KIT region and suggest the possibility of the existence of other types of mutations in this region in GISTs.

Aged↗
PubMed2001

[Evaluation of efficiency of ACD-CPR and STD-CPR; a multi-institutional study].

We compared the efficacy of ACD-CPR and STD-CPR based on 64 multi-institutional reports. No significant differences were observed in the rate of restoration of spontaneous circulation (ROSC) and in cardiopulmonary parameters during CPR using the two methods. There were 5 cases in which cardiopulmonary parameters improved after switching from STD-CPR to ACD-CPR and, eventually, in two of them spontaneous circulation was restored. In the ROSC cases of both groups, ETCO2 and values of SpO2, PaO2, and systolic BP at 30 minutes were higher than those of non-ROSC cases. ETCO2 never exceeded 20 mmHg in the non-ROSC cases, but it was higher in the ROSC cases. ACD-CPR is a good choice when trained persons are present or when extra hands are available to continue the CPR.

Adolescent↗
PubMed2000

Designed cyclopentenone prostaglandin derivatives as neurite outgrowth-promoting compounds for CAD cells, a rat catecholaminergic neuronal cell line of the central nervous system.

Here we reported the effects of neurite outgrowth-promoting prostaglandins (NEPP's) on neurons of the central nervous system (CNS). Serum deprivation promoted neurite outgrowth from CAD cells, a CNS-derived cathecholaminergic neuronal cell line. NEPP's (0.05-0.2 microM) accelerated the neurite outgrowth from CAD cells in serum-free medium but didn't in serum-containing medium. Through the study of structure-function relationship with the NEPP's 1-10, NEPP 10 (13,14-dihydro-15-epi-Delta(7)-prostaglandin A(1) (methyl ester) revealed the best compound, exhibiting potent neurite outgrowth-promoting activity with minimal cytotoxicity, suggesting that it is the best compound for drug development.

Animals↗
PubMed2000

Copper does not alter the intracellular distribution of ATP7B, a copper-transporting ATPase.

Wilson's disease is a genetic disorder characterized by the accumulation of copper in the body due to a defect of biliary copper excretion. However, the mechanism of biliary copper excretion has not been fully clarified. We examined the effect of copper on the intracellular localization of the Wilson disease gene product (ATP7B) and green fluorescent protein (GFP)-tagged ATP7B in a human hepatoma cell line (Huh7). The intracellular organelles were visualized by fluorescence microscopy. GFP-ATP7B colocalized with late endosome markers, but not with endoplasmic reticulum, Golgi, or lysosome markers in both the steady and copper-loaded states. ATP7B mainly localized at the perinuclear regions in both states. These results suggest that the main localization of ATP7B is in the late endosomes in both the steady and copper-loaded states. ATP7B seems to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes.

Adenosine Triphosphatases↗
PubMed2000

Role of ATP7B in biliary copper excretion in a human hepatoma cell line and normal rat hepatocytes.

BACKGROUND & AIMS: Wilson's disease is a genetic disorder characterized by the accumulation of copper in the body caused by a defect of biliary copper excretion. The Wilson's disease gene has been cloned; however, the precise localization of the gene product (ATP7B) and its role in biliary copper excretion have not been clarified. METHODS: We constructed a chimeric protein between green fluorescent protein (GFP) and ATP7B (GFP-ATP7B) and expressed it in a human hepatoma cell line (Huh7) and isolated rat hepatocytes. The Golgi apparatus, late endosomes, lysosomes, and bile canaliculus were visualized by fluorescence microscopy. Brefeldin A and nocodazole were used to redistribute the Golgi proteins. Bafilomycin A1 was used to analyze the association between GFP-ATP7B and the late endosomes. RESULTS: GFP-ATP7B colocalized with rhodamine-dextran and late endosome markers but not with the Golgi markers, lysosome markers, or a tight junction protein. Brefeldin A and nocodazole redistributed the Golgi proteins, but they did not affect the distribution of ATP7B. CONCLUSIONS: Although it is widely believed that ATP7B is located at the Golgi apparatus, its main localization is in late endosomes. ATP7B seems to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes.

Adaptor Protein Complex gamma Subunits↗
PubMed2000

Experimental study on liver regeneration after simultaneous partial hepatectomy and pancreatectomy.

In this study, we performed hepatectomy and pancreatectomy to assess the physiological contribution of the pancreas, especially in terms of endocrine function to hepatic regeneration. Group 1 Wistar rats underwent 70% hepatectomy and group 2 rats underwent 70% hepatectomy plus 50% pancreatectomy. The time course assessment of liver regeneration rates obtained by Fishback's formula demonstrated a difference in rates between the two groups as early as day 3 or day 7 after surgery. Since levels of both PCNA-positive cells and serum transforming growth factor-alpha (TGF-alpha) were significantly higher in the hepatectomy only group, we could prove the difference of liver regeneration between the two groups. We have concluded that pancreatectomy retards the liver regeneration initiation processes occurring from 24 h to 3 days after evisceration. Glucagon-insulin molar ratios most significantly differed between the two groups 3 days after evisceration in the present study. This result was due to increased glucagon level of group 2 at day 3 after evisceration. Our findings suggest that 50% partial pancreatectomy inhibits the rate of hepatic regeneration, thereby altering the supply of pancreatic hormones, especially glucagon.

Journal Article↗
PubMed2000

Facilitatory roles of novel compounds designed from cyclopentenone prostaglandins on neurite outgrowth-promoting activities of nerve growth factor.

Cyclopentenone prostaglandins (PGs) are known to arrest the cell cycle at the G(1) phase in vitro and to suppress tumor growth in vivo. However, their effects on neurons are unclear. Here, we report that some cyclopentenone PGs function as neurite outgrowth-promoting factors. They promoted neurite outgrowth from PC12 cells and from dorsal root ganglion explants but only in the presence of nerve growth factor (NGF). We refer to these PGs as neurite outgrowth-promoting PGs (NEPPs). Through study of the structure-function relationship of NEPP1-10 and related compounds, we found that the cross-conjugated dienone moiety of NEPPs was essential for promoting neurite outgrowth, and NEPP10 was concluded to be the best candidate for drug development. We also investigated the intracellular mechanism of the promotion by NEPPs and obtained evidence that immunoglobulin heavy chain binding protein/glucose-regulated protein 78 (BiP/GRP78) plays a role in the promotion, based on the following observations: Antisense nucleotides for BiP/GRP78 gene blocked the promotion of neurite outgrowth; BiP/GRP78 protein level increased in response to NEPPs; and overexpression of BiP/GRP78 protein by adenoviral gene transfer promoted the neurite outgrowth by NGF.

Adenoviridae↗
PubMed2000

Differences in the mineral contents between falx cerebri and tentorium cerebelli.

To elucidate age-related changes of the dura mater, the authors investigated age-related changes of mineral contents in the falx cerebri and the tentorium cerebelli by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 10 men and 15 women, ranging in age from 65 to 102 yr. The contents of calcium, phosphorus, and magnesium increased progressively with aging in the falx cerebri, whereas the contents of sulfur, iron, and zinc remained constant, being independent of age. In regard to the tentorium cerebelli, the contents of calcium, phosphorus, and magnesium seemed to increase progressively with aging, but the contents of sulfur, iron, and zinc hardly changed with aging. It was noteworthy that there were no significant relationships between the falx cerebri and the tentorium cerebelli in such element contents as calcium, phosphorus, magnesium, sulfur, iron, and zinc.

Aged↗
PubMed2000

The human multidrug resistance-associated protein (MRP) gene family: from biological function to drug molecular design.

The ATP-binding cassette transmembrane proteins play an important role in transport of drugs as well as of biologically active endogenous substances. The human multidrug resistance-associated protein (MRP) subfamily consists of at least six members, exhibiting a wide spectrum of biological functions. MRP1 operates as an ATP-dependent primary active transporter for substrates conjugated with glucuronide, sulfate or glutathione. Leukotriene C4 is an important endogenous substrate for MRP1. Glutathione serves as a cofactor in MRP1-mediated drug transport as well. Genes encoding both MRP1 and the catalytic subunit of gamma-glutamylcysteine synthetase (gamma-GCS) are coordinately regulated in cultured cancer cell lines as well as colorectal cancer tissues from colon cancer patients. The induction of MRP1 and gamma-GCS expression by oxidative stress varies among different cell lines, and p53 mutations are associated with elevated levels of induction. To modulate the transport function of MRP1, we have synthesized novel glutathione derivatives as photoreactive biochemical probes targeting the transporter protein. GIF-0019 restored the cellular sensitivity of MRP1-overexpressing drug-resistant cancer cells to anticancer prostaglandins in vitro, which was characterized by enhanced mRNA levels of the cyclin-dependent kinase inhibitor p21, suppressed c-myc expression and G1 arrest.

ATP-Binding Cassette Transporters↗
PubMed1999

[35S]S-[5-(4-benzoylphenyl)pentyl]glutathione: a versatile radioligand targeting GS-X pumps with the ability of photoaffinity labeling.

[35S]S-[5-(4-benzoylphenyl)pentyl]glutathione (GIF-0017) as a biochemical probe targeting the ATP-dependent organic anion transporters GS-X pumps was synthesized by the reaction of [35S]glutathione and excess 4-(5-bromo)pentylbenzophenone under alkaline conditions, with the radiochemical yield of 24-33% after HPLC purification. Photolysis of the mixture of [35S]GIF-0017 and plasma membrane vesicles prepared from the MRP1 cDNA-transfected LLC-PK1 cells resulted in radio-labeling of a 180-kDa membrane protein. Immunoprecipitation and western blotting using an anti-MRP1 monoclonal antibody confirmed that the [35S]GIF-0017-labeled protein was the MRPI/GS-X pump.

Animals↗
PubMed1999

Gene mutation of transforming growth factor beta1 type II receptor in hepatocellular carcinoma.

Alteration of transforming growth factor beta1 (TGF-beta1) type II receptor (RII) appears to cause unresponsiveness to TGF-beta1 in tumorigenic cells. Defect in the mononucleotide repeat sequence, i.e., poly A region of TGF-beta1RII gene has been reported to be related to replication error-positive cancer cells. We examined if there is any TGF-beta1RII mutation in a coding microsatellite in hepatocellular carcinoma (HCC). Genomic DNAs were extracted from formalin-fixed, paraffin-embedded liver tissues obtained at surgery or autopsy in 3 normal individuals and 96 patients with hepatitis C virus-induced chronic liver disease; 3 with chronic hepatitis, 20 with liver cirrhosis and 73 with HCC. The DNA was PCR-amplified at 2 segments of TGF-beta1RII: poly A region which includes the (A)10 microsatellite sequence, and poly GT region. PCR products were directly sequenced. DNA from normal and patients with chronic liver disease contained the 10 wild-type adenines but 3 cases with liver cirrhosis in whom there were only 9 adenines within poly A tract. This microdeletion of one A resulted in a frameshift and truncated a predicted length of amino acids. In HCC lesions, the same deletion was noted in 4 cases (25%) of well-differentiated type, 10 (40%) of moderately differentiated type, 18 (53%) of poorly differentiated type. None of the lesions had mutations within the GT region. Our findings indicate that one adenine deletion of poly A microsatellite tract within TGF-beta1RII is frequently detected in patients with HCC, and the mutation may cause the abrogation of the function of TGF-beta1RII gene.

Base Sequence↗