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T Takahara

Publications and source records attributed to T Takahara.

At least 19 recordsLinked to original sources
PubMed2003

Hepatocyte growth factor gene therapy accelerates regeneration in cirrhotic mouse livers after hepatectomy.

BACKGROUND: Impaired regeneration and dysfunction of the cirrhotic liver following partial hepatectomy (PHx) are the most serious risk factors for postoperative liver failure. AIMS: Using naked hepatocyte growth factor (HGF) plasmid by the electroporation (EP) in vivo method, we investigated HGF for its role and mechanism of proliferation and restoration of liver mass in cirrhotic mice following PHx. ANIMALS: Eight week old female mice were used. METHODS: HGF plasmid 50 micro g was injected intramuscularly and transferred by EP in vivo once a week for three weeks. After establishment of carbon tetrachloride induced cirrhosis, mice underwent PHx. The HGF treated group was given naked HGF plasmid four days before PHx, and additional HGF was given once a week until they were killed, while a control group was given only empty plasmid. Mice were killed 2, 4, 10, and 14 days after PHx. Morphological and functional restoration of the liver were examined, as well as activation of mitogen activated protein kinase (MAPK) and mRNA levels of HGF activator (HGFA). RESULTS: The HGF treated group demonstrated a continuous threefold increase in HGF levels in plasma. Therapy with HGF in cirrhotic PHx resulted in effective liver regeneration via restoration of HGFA and activation of MAPK p44/p42, accelerated normalisation of liver function, and increased collagen degradation. CONCLUSIONS: HGF gene therapy by in vivo EP may be useful for hepatic resection in cirrhotic livers by stimulating liver proliferative and collagenolytic capacities, as well as accelerating functional recovery.

Animals↗
PubMed2002

Attenuated acute liver injury in mice by naked hepatocyte growth factor gene transfer into skeletal muscle with electroporation.

BACKGROUND: Hepatocyte growth factor (HGF) plays an essential role in hepatic development and regeneration, and shows proliferative and antiapoptotic activity in hepatocytes. AIMS: To establish an effective new method for HGF gene transfer in vivo and to investigate its effects in acute experimental liver injury. ANIMALS: Eight week old female mice were used. METHODS: Rat HGF gene in a modified pKSCX plasmid was transferred to the tibialis anterior muscle by electroporation using a pulse generator. Four days later, plasma HGF concentrations were determined by enzyme linked immunosorbent assay every two days for three weeks. To confirm the efficacy of electroporation, a plasmid bearing green fluorescence protein (GFP) was transferred similarly. Four days after electroporation, carbon tetrachloride (CCl(4)) was administered to mice to induce acute liver injury. Plasma alanine aminotransferase (ALT) activity was measured. Hepatic apoptosis was assessed by Hoechst 33258 staining and the TUNEL method. RESULTS: Fluorescence microscopy showed strong green fluorescence where the GFP gene had been transferred into muscle. In mice given the HGF gene, HGF in plasma was increased up to fourfold from pretreatment amounts, peaking 6-9 days after electroporation and quickly decreasing within three weeks. Compared with the group without HGF transfer, the percentage of apoptotic hepatocytes after CCl(4) intoxication was significantly lower, as was ALT activity. In addition, ALT activity normalised more rapidly in the HGF gene transfer group. CONCLUSIONS: Naked DNA injection and transfer by electroporation efficiently brings about HGF expression in vivo, which can attenuate acute liver injury.

Alanine Transaminase↗
PubMed2001

Recombination hot spot of hepatitis B virus genome binds to members of the HMG domain protein family and the Y box binding protein family; implication of these proteins in genomic instability.

OBJECTIVE: Previously we hypothesized that the occurrence of hepatocellular carcinoma (HCC) is enhanced by genomic instability induced by the integrated hepatitis B virus (HBV) DNA. Using an in vitro recombination assay, we showed that a subgenomic fragment of HBV DNA designated 15AB (nt1855-1914) is indispensable for in vitro recombination, and also showed the existence of 15AB binding protein. On the assumption that the 15AB binding protein may be a candidate cellular recombinogenic protein which accelerates genomic instability and hepatocarcinogenesis, we tried to isolate it by southwestern screening. RESULTS AND CONCLUSION: We obtained several positive clones including mouse upstream binding factor (UBF) and DNA binding protein A (dbpA). UBF belongs to an HMG domain protein family and dbpA belongs to a Y box binding protein family. 15AB binding seemed to be mediated by the conserved DNA binding domains in these families, because other members in the families such as HMG1 and YB-1 also bound to 15AB. We report them here because several documents have already suggested the possible association of these families and DNA recombination.

Animals↗
PubMed2001

Antisense oligonucleotides specific to mutated K-ras genes inhibit invasiveness of human pancreatic cancer cell lines.

BACKGROUND/AIMS: Point mutations of the K-ras gene are detected in > 90% of human pancreatic cancers and may play an important role in tumorigenesis. However, correlations between mutant K-ras and the invasive activity of the tumor have remained unclarified. METHODS: 17-merphosphorothioate antisense oligonucleotides targeting K-ras point mutations were transfected into three kinds of human pancreatic cancer cell lines (MIAPaCa-2, PANC-1, and BxPC-3), and the invasive activity was investigated using an in vitro chemoinvasion assay. RESULTS: Antisense oligonucleotides strongly inhibited the invasive activity of the cell lines with mutant K-ras genes (MIAPaCa-2, PANC-1), but not in that with a wild-type K-ras (BxPC-3). CONCLUSION: Antisense oligonucleotides specific to mutated K-ras genes inhibited the invasiveness of human pancreatic cancer cell lines. Specific antisense therapy to the point mutation of K-ras might be a new anticancer strategy for pancreatic cancer.

Blotting, Western↗
PubMed2000

Heterogeneous Sp1 mRNAs in human HepG2 cells include a product of homotypic trans-splicing.

Sp1 is one of the well documented transcription factors, but the whole structure of human Sp1 has not been determined yet. In the present study, we isolated several cDNAs representing two forms of human Sp1 mRNA with different 5'-terminal structures in HepG2 cells. Isolation of a genomic clone established that one of the cDNAs represents the mRNA having consecutive alignment of exons, which allowed deducing the complete amino acid sequence for human Sp1. Another cDNA clone had a surprising structure that possessed an alignment of exons 3-2-3. Both reverse transcriptase-polymerase chain reaction and RNase protection assays confirmed accumulation of the two forms of Sp1 mRNA in HepG2 cells. Because Southern blot analysis suggested that exon 3 is of a single copy in the genome, the cDNA clone having the duplicated sequences for exon 3 appeared to reflect the trans-splicing between pre-mRNAs of human Sp1.

Amino Acid Sequence↗
PubMed2000

Thrombotic thrombocytopenia purpura caused by piperacillin successfully treated with plasma infusion.

An 81-year-old man was admitted to the hospital with a fever and loss of appetite. After treatment with piperacillin sodium (PIPC), the patient exhibited thrombocytopenia, hemorrhagic colitis, and drug-induced skin eruption. On the fifth day after PIPC induction, he further experienced neurological abnormalities, such as disorientation and confusion, renal dysfunction, and microangiopathic hemolytic anemia (MAHA). The patient was diagnosed with thrombotic thrombocytopenic purpura (TTP) on the basis of thrombocytopenia, MAHA, renal dysfunction, fever, and neurological abnormalities. Infusion of fresh-frozen plasma was initiated for treatment. His condition improved markedly after this treatment. It is rare for TTP to be accompanied with hemorrhagic colitis and skin eruption. These symptoms were induced by PIPC and were successfully treated with plasma infusion.

Aged↗
PubMed2000

Novel immunogenicity of Oka varicella vaccine vector expressing hepatitis B surface antigen.

Recombinant Oka (ROka) varicella vaccine expressing hepatitis B surface antigen (HBsAg) and subunit HBsAg vaccine (SHV) were used as primary and booster HBsAg vaccines in 3 combinations (SHV-SHV, SHV-ROka, and ROka-SHV) in guinea pigs. Immune responses to HBsAg and varicella-zoster virus gE:gI were evaluated. The 3 combinations induced similar levels of the lymphocyte proliferation response to HBsAg. Of the 3 combinations, SHV-SHV induced the strongest antibody response to an "a" loop of HBsAg and to the whole HBsAg. Its ratio of antibody titer to this loop versus HBsAg was significantly higher than that in SHV-ROka, suggesting the supplementary recognition of the conformational epitope of HBsAg in SHV-ROka. SHV-ROka induced delayed-type hypersensitivity (DTH) to the HBsAg and gE:gI produced in infected cells. Thus, ROka induced DTH to HBsAg and enhanced recognition of the conformational epitope. ROka varicella vaccine may serve as a novel vaccine vector to induce a Th1-type immune response.

Animals↗
PubMed1999

T1 Breast Cancer Associated with Von Recklinghausen's Neurofibromatosis.

A rare case of breast cancer associated with von Recklinghausen s neurofibromatosis is reported. This case and review of the literature illustrate the problems of clinical diagnosis. A 66-year-old woman who had undergone sigmoidectomy for sigmoid colon cancer two years previously, was admitted to the hospital because of a left breast skinretraction in October, 1998. The patient had von Recklinghausen fs disease (neurofibromatosis type 1). The TNM clinical staging was T1cN0M0. Modified radical mastectomy was performed. The histopathological diagnosis of the breast tumor was invasive ductal carcinoma and the skin tumor was neurofibroma. The pTNM pathological staging was pT1cN1aM0. Among patients similar to our case, almost all were staged higher than T2. This may be because multiple neurofibromas obscure breast mass at palpation, leading to delayed detection of the cancer. Systemic and careful exploration is essential for patients with von Recklinghausen's neurofibromatosis to detect breast cancer at an early stage.

Journal Article↗
PubMed1999

Functional B-cell response in intrahepatic lymphoid follicles in chronic hepatitis C.

Intrahepatic lymphoid follicle (ILF) formation is one of the most characteristic and commonly observed histological features in patients with chronic hepatitis C. However, little is known regarding whether follicles in the liver belong to functional lymphoid tissues, where B cells are activated, differentiated, and proliferated, or if the lymphocytes are merely infiltrated after recruitment from the secondary lymphoid organs. To ascertain this possibility, we examined the expression of markers for B-cell activation, differentiation, and proliferation in ILFs in patients with chronic hepatitis C using surgically resected specimens, and compared them with specimens of perihepatic lymph nodes by an immunohistochemical technique. Germinal center (GC) formation in the ILFs was frequently found in HCV-positive cases. The distribution of immunoglobulin M (IgM)-, IgD-, and IgG-positive cells and the expression patterns of Ki-67, CD23, or bcl-2 and bcl-6 gene products in the follicles with GC formation in the liver of patients with chronic hepatitis C were similar to those of lymph nodes, indicating that B cells are activated, proliferated, and differentiated in the ILFs with GC formation in patients with chronic hepatitis C. Oligoclonal expansion of B cells in the livers with ILFs was confirmed by an analysis of immunoglobulin heavy chain (IgH) gene rearrangement determined by polymerase chain reaction (PCR). These data strongly suggest that ILFs with GC formation, which are frequently found in patients with chronic hepatitis C, may functionally be the same as those found in lymph nodes with respect to B-cell expansion and maturation.

Adult↗
PubMed1999

Expression of matrix metalloproteinase-13 and tissue inhibitor of metalloproteinase-1 in acute liver injury.

BACKGROUND/AIMS: Matrix metalloproteinase-13, one of the principal neutral proteinases capable of cleaving native fibrillar collagens, is important in the degradation and remodeling of extracellular matrix. However, its precise expression in liver injury has not been characterized. We examined the kinetics of the expression of matrix metalloproteinase-13 and one of its specific inhibitors, tissue inhibitor of metalloproteinase-1, in acute liver injury in rats. METHODS: Acute liver injury was induced by administration of carbon tetrachloride or two different doses of D-galactosamine hydrochloride in Wistar rats. Hepatic matrix metalloproteinase-13 and tissue inhibitor of metalloproteinase-1 mRNA levels were then examined by Northern blotting. RESULTS: All rats survived after liver injury induced by carbon tetrachloride or low doses of D-galactosamine hydrochloride. However, rats died 5 days after induction of liver injury by high doses of D-galactosamine hydrochloride. In carbon tetrachloride-induced liver injury, matrix metalloproteinase-13 mRNA was transiently increased between 6 h and 1 day after injury. Tissue inhibitor of metalloproteinase-1 mRNA expression was increased between 6 h and 3 days after the peak of matrix metalloproteinase-13 expression. Similar patterns of matrix metalloproteinase-13 and tissue inhibitor of metalloproteinase-1 expression were observed in low-dose D-galactosamine hydrochloride-induced liver injury. In contrast, in high-dose D-galactosamine hydrochloride-induced liver injury, tissue inhibitor of metalloproteinase-1 expression peaked before matrix metalloproteinase-13 expression, which was increased 2 days after injury. Both mRNA levels continued to increase until death. CONCLUSIONS: Transient expression of matrix metalloproteinase-13, followed by that of tissue inhibitor of metalloproteinase-1, was observed during recovery from acute liver injury induced by carbon tetrachloride and low-dose D-galactosamine hydrochloride. In contrast, disordered expression of matrix metalloproteinase-13 was observed in fatal liver injury caused by high-dose D-galactosamine hydrochloride. These results indicate that matrix metalloproteinase13 plays an important role in the early phase of recovery from liver injury.

Animals↗
PubMed1999

Spatial distribution of tissue inhibitor of metalloproteinase-1 mRNA in chronic liver disease.

BACKGROUND/AIMS: Tissue inhibitor of metalloproteinase-1, a specific inhibitor of matrix metalloproteinases, plays an important role in the pathogenesis of fibrosis and tumor progression. However, the precise expression of tissue inhibitor of metalloproteinase-1 messenger RNA in human hepatic fibrosis has not yet been defined. We investigated the spatial distribution of tissue inhibitor of metalloproteinase-1 messenger RNA in chronic human liver disease. METHODS: Northern and in situ hybridization of probes to tissue inhibitor of metalloproteinase-1 messenger RNA were performed in specimens from 16 surgically resected human livers. Immunohistochemical staining of sections for tissue inhibitor of metalloproteinase-1 and immunoelectron microscopy were also performed. RESULTS: Northern hybridization demonstrated that expression of tissue inhibitor of metalloproteinase-1 messenger RNA was increased 3.9-fold in mild chronic hepatitis, 6.8-fold in moderate chronic hepatitis, and 6.4-fold in cirrhosis, compared with control liver. In situ hybridization showed the expression of tissue inhibitor of metalloproteinase-1 messenger RNA in spindle-shaped cells in the fibrous septa and lobules in chronic hepatitis and cirrhosis; these cells were immunohistochemically positive for a-smooth muscle actin. Immunoelectron microscopy revealed localization of tissue inhibitor of metalloproteinase-1 in between fibers, to the rough endoplasmic reticula of stellate cells located in the lobules and periportal areas, and to fibroblasts in the fibrous septa. These results indicate that tissue inhibitor of metalloproteinase-1 was produced mainly by stellate cells in the specimens of chronic liver diseases. CONCLUSIONS: Expression of tissue inhibitor of metalloproteinase-1 messenger RNA is increased in hepatic fibrosis and stellate cells are involved primarily in its expression.

Adult↗
PubMed1999

Increased expression of plasminogen activator and plasminogen activator inhibitor during liver fibrogenesis of rats: role of stellate cells.

BACKGROUND/AIMS: Plasminogen activators and plasminogen activator inhibitors are important regulators of the balance between the proteolytic and antiproteolytic activities that determine extracellular matrix turnover. We examined the expression of plasminogen activator-plasmin system components in experimental liver fibrosis of rats. METHODS: Liver fibrosis was produced in rats by injecting carbon tetrachloride for 6 to 12 weeks. Gene expression for plasminogen activator inhibitor-1 (PAI-1), urokinase and tissue plasminogen activators (uPA and tPA), urokinase plasminogen activator receptor (uPAR), and transforming growth factor-beta1 (TGF-beta1) was examined by Northern analysis. Western analysis was performed to detect protein expression of PAI-1, uPA and uPAR. An immunohistochemical study was performed to detect the localization of PAI-1. Additionally, primary cultured liver cells were examined by Northern and Western analyses for this protein with or without prior incubation with TGF-beta1. RESULTS: At 6 weeks, when fibrosis had occurred, uPA and uPAR mRNAs had increased 2.8-fold and 1.8-fold, respectively; PAI-1 and tPA mRNA levels were unchanged. At the cirrhotic stage (9 to 12 weeks), mRNA levels for PAI-1, uPA, uPAR and tPA were all increased. Western analysis also showed increased uPA and uPAR expressions in fibrotic liver, and increased PAI-1, uPA and uPAR expressions in cirrhotic liver. PAI-1 protein was also demonstrated immunohistochemically along sinusoids, vessels, and bile duct cells of normal and fibrotic liver. In liver cell cultures, Kupffer cells, hepatocytes, and especially stellate cells, expressed PAI-1. Expression was enhanced in stellate cells cultured from fibrotic or cirrhotic liver or stimulated in vitro with TGF-beta1. CONCLUSION: Though increased uPA and uPAR may act on matrix degradation in fibrotic liver, increased PAI-1 together with uPA, uPAR and tPA are associated with overall inhibition of matrix degradation in cirrhotic liver. Hepatic stellate cells are an important source of PAI-1 during liver fibrosis.

Animals↗
PubMed1999

An improved method for the purification of stellate cells from rat liver with dichloromethylene diphosphate (CL2MDP).

Hepatic perisinusoidal cell population consists of hepatic stellate cells, Kupffer cells, endothelial cells, and Pit cells. These cells are isolated by enzymic digestion and purified by density gradient centrifugation. With isolation of stellate cells, conventional method is unable to eliminate the contamination of Kupffer cells because the densities of these two cells are similar. We report here an improved method for isolation of highly purified hepatic stellate cells, using dichloromethylene diphosphate (CL2MDP), which has selective cytotoxicity of Kupffer cells. Three days after the single intravenous administration of liposome-encapsulated CL2MDP, the Kupffer cells disappeared almost completely from the liver. Following Percoll density gradient centrifugation, the purity of the hepatic stellate cells exceeded 98% without any contamination of the Kupffer cells. Kupffer cells are reported to affect the physiological functions of stellate cells. The availability of highly purified stellate cells will facilitate the investigation of their functions in primary culture.

Animals↗
PubMed1999

Adult T-cell leukemia/lymphoma in which the pathohistological diagnosis was identical to that of Ki-1 positive anaplastic large cell lymphoma.

A 65-year-old man developed severe lumbago and a loss of appetite two months before presentation. A computerized tomograph at admission revealed soft tissue masses destroying the Th12, L4 and L5 vertebral bones. We diagnosed the lesions to be metastatic bone tumors, but the primary focus could not be determined. Just after the irradiation treatment, abnormal lymphocytes were detected in the peripheral blood cells. Under the suspicion of adult T-cell leukemia/ lymphoma (ATL), we thus performed a lymph node biopsy. The specimens were histologically composed of Ki-1 positive anaplastic large cell lymphoma (ALCL). The lymphoma cells demonstrated a biclonal integration of HTLV-1 proviral DNA. After 6 cycles of chemotherapy, the patient has demonstrated a partial and favorable remission from ATL.

Aged↗
PubMed1999

[Time-resolved three-dimensional contrast-enhanced MR angiography of the carotid artery].

Contrast-enhanced MR angiography (ceMRA) allows practical carotid arteriography without venous enhancement. However, it requires some intricate preparation such as a test bolus of the contrast agent or determination of the tracking volume even in the automatic triggering Smartprep system. The purpose of this study was to obtain carotid ceMRA without any preparation by means of a repeated multiple ultrashort three-dimensional MRA sequence (e3d56), i.e., time-resolved MRA (trMRA). Twenty-three patients underwent sagittal trMRA using a 1.0-Tesla superconducting unit. Multiple projection angiograms are acquired in three contiguous phases with a time resolution of 6 seconds per slab, including 10 partitions, after a bolus injection of 10 ml of Gd-DTPA followed by 20 ml of saline at 2 ml/sec. In all patients, the signal from the arteries could be separated from that of the veins in at least one phase. Carotid trMRA with 6-sec temporal resolution is a reliable technique for selective arteriography, avoiding the necessity of timing the contrast agent bolus.

Adult↗
PubMed1999

Il-1, EGF, and HGF suppress the antiviral activity of interferon in primary monkey hepatic parenchymal cells.

The purpose of this study was to elucidate the mechanism behind low efficacy of interferon therapy to hepatitis C virus infected patients by using primary monkey hepatic parenchymal cells as a surrogate of primary human liver cells. The effects of various cytokines on the antiviral activity of IFNs in the monkey hepatic cells were studied to search for physiological inhibitors. Interleukin-1 alpha, EGF, and HGF showed suppressive effects on the antiviral activity of IFN-alpha, -beta in primary monkey hepatic cells when examined by the yield reduction method using vesicular stomatitis virus (VSV). In contrast, 50 ng/ml of TNF and IL-6 had no suppressive effect on the IFN-induced antiviral state in the hepatic cells.

Animals↗