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T Okamoto

Publications and source records attributed to T Okamoto.

At least 109 records · Page 6Linked to original sources
PubMed2001

Efficient and cancer-selective gene transfer to hepatocellular carcinoma in a rat using adenovirus vector with iodized oil esters.

Gene therapy for cancer requires efficient, selective gene transfer to cancer cells. In gene therapy for hepatocellular carcinoma (HCC), gene transfer is efficient for small tumors, but not for large tumors. The delivery of anticancer agents and of iodized oil esters as embolic agents through tumor-feeding arteries is known as transarterial embolization. We speculate that genes may be efficiently and selectively transferred for HCC using iodized oil esters because these esters may remain together with a genetic vector within HCC selectively. Hence, we have studied the effect of iodized oil esters on adenovirus vector-mediated gene transfer for HCC in vivo. A rat model of HCC induced with diethylnitrosamine and phenobarbital was injected with either AxCALacZ, which expresses the beta-galactosidase of Escherichia coli, or AxCALacZ and iodized oil esters into the hepatic artery. Histological comparisons revealed that the beta-galactosidase expression in the rats with HCC injected with AxCALacZ and iodized oil esters was greater (P<.0001) in small tumors (P=.0046) and large tumors (P=.0023), and more selective (P=.0229) than in only AxCALacZ-injected rats. These results suggest that iodized oil esters are injected into hepatic artery together with adenovirus vector, and that genes may be efficiently and cancer-selectively transferred to HCC.

Adenoviridae↗
PubMed2001

Development of new assays and improved procedures for the purification of recombinant human chymase.

Chymase mediates a major alternative way of angiotensin II production from angiotensin I beside angiotensin converting enzyme in the final step of the renin-angiotensin system. This enzyme is also involved in other physio-pathological processes such as angiogenesis, atherosclerosis and inflammation. Several purification attempts of natural or recombinant chymase were reported in the literature. Most of these reports were not successful in obtaining the recombinant enzyme in a highly active form and in large quantity. In the present study, we describe a facile route for the purification of the human recombinant chymase. Chymase being produced as inactive prochymase, to be cathepsin C-activated, newly raised anti-chymase Ig were used to follow the purification. In order to complete the available tools for the search of chymase inhibitors, we developed and assessed a new 96-well plate based assay for the measurement of enzyme activity, as well as a low throughput, HPLC-based one. The assays used an original derivative of angiotensin I, or the native hormone. Chymase was produced in CHO cells and appropriately matured. The amount of enzyme obtained at the end of the process is compatible with the medium-throughput screening (up to 10,000 points per day), about 800 microg x L(-1) of culture medium with a specific activity of 6.16 mmol of angiotensin I cleaved per minute per mg of protein. All the biological and technical tools are now available for the discovery of new classes of chymase inhibitors.

Animals↗
PubMed2001

Effects of different types of K+ channel modulators on the spontaneous myogenic contraction of guinea-pig urinary bladder smooth muscle.

In the present study, effects of different types of K+ channel modulators on the spontaneous rhythmic contractile activity were examined in guinea-pig urinary bladder smooth muscle (UBSM). Guinea-pig UBSM exhibited myogenic rhythmic contraction in the presence of atropine (1 microM), phentolamine (1 microM), propranolol (1 microM), suramin (10 microM) and tetrodotoxin (1 microM). Nisoldipine (100 nM) or diltiazem (10 microM) substantially diminished UBSM contractile activity. Nisoldipine-resistant component of UBSM rhythmic contraction was further inhibited by gadolinium (200 microM). Iberiotoxin (50 nM), a selective blocker of large-conductance, voltage-gated Ca2+-activated K+ (K(Ca)) (BK) channel, dramatically increased both contraction amplitude and frequency whereas NS-1619 (30 microM), which increases BK channel activity, decreased them. Apamin (100 nM), a selective blocker of small-conductance, K(Ca) (SK) channel, increased contraction amplitude but decreased frequency. A blocker of voltage-gated K+ (Kv) channel, 4-aminopyridine (100 microM), significantly increased contraction frequency. E-4031, a blocker of a novel inwardly rectifying K+ channel, i.e. the human ether-a-go-go-related gene (HERG) K+ channel, significantly increased contraction amplitude. Glibenclamide (1-10 microM) (K(ATP) channel blocker) and Ba2+ (10 microM) (conventional K(ir) channel blocker) did not exhibit conspicuous effects on spontaneous contractile activity of UBSM. These findings imply that two types of K(Ca) (BK and SK) channels have prominent roles as negative feedback elements to limit extracellular Ca2+ influx-mediated guinea-pig UBSM contraction by regulating both amplitude and frequency. It was also suggested that both non-K(Ca) type of K+ (Kv and HERG-like K+) channels may contribute to the regulation of UBSM myogenic rhythmic contraction.

4-Aminopyridine↗
PubMed2001

Killer T-cell induction in patients with blastic natural killer cell lymphoma/leukaemia: implications for successful treatment and possible therapeutic strategies.

A rare form of putative natural killer (NK) cell lymphoma called blastic NK cell lymphoma appears to be clinicopathologically distinctive in showing a homogenous lymphoblast, variable expression of CD2, CD4, CD56 and TdT, negative for surface CD3, T-cell receptor antigen, CD16, CD34 and lack of association with Epstein-Barr virus (EBV). We report two patients with blastic NK cell lymphoma and describe the interesting clinical studies. The patients presented with cutaneous plaques. Both patients had adenopathy, and one had marrow involvement at presentation. Unlike in many NK and NK-like T-cell disorders, azurophilic cytoplasmic granules were absent. They expressed intermediate density CD45. In addition, the cells were positive for HLA-DR, CD2, CD4, CD56 and TdT, and negative for EBV transcripts. In spite of the advanced clinical stage, complete remission was achieved by conventional chemotherapy. After interleukin 2 expansion of tumour-infiltrating bone marrow and lymph node cells from the patients, cytotoxic T-cell lines with rearranged T-cell receptor genes were established. They showed specific killing activity against autologous tumour cells in an MHC-restricted fashion, with possible implications for treatment. In addition, upon cessation of maintenance chemotherapy, one patient developed overt leukaemia with blasts expressing CD33 antigens, suggesting a continuous spectrum of blastic NK cell lymphoma to myeloid/NK cell precursor acute leukaemia.

Aged↗
PubMed2001

Photocatalytic deposition of a gold nanoparticle onto the top of a SiN cantilever tip.

We propose a new technique for depositing a gold nanoparticle onto the tip of a dielectric support. We employed the photocatalytic effect of titanium dioxide for the deposition. When the titanium dioxide immersed in a solution including gold ions is subject to optical exposure, the excited electrons in the conduction band reduce gold ions into gold metal. Illumination by an evanescent wave generated with a total reflection configuration limits the deposition region to the very tip. In experiments we obtained 100-300 nm gold particles on SiN cantilever tips for atomic force microscopes. The contrast of evanescent interference fringes measured by a near-field scanning optical microscope with this gold nanoparticle probe has proved to be higher than that with a non-deposited SiN probe by a factor of 1.5.

Journal Article↗
PubMed2001

Experimental evaluation of the V-point heparin-bonding system applied to a dense-membrane artificial lung during 24-hour extracorporeal circulation in beagles.

Heparin was covalently bonded to a hollow-fiber dense-membrane artificial lung and circuit using a silane coupling agent and polyethyleneimine as a spacer. This study investigated whether the novel artificial lung could sustain prolonged extracorporeal lung assist (ECLA) by venoarterial bypass in beagles using minimal anticoagulants. We maintained ECLA for 24 h in 3 groups of minimal systemic heparinization, heparinization with the new anticoagulant nafamostat mesilate, and without any systemic anticoagulant. The results were assessed from the functional performance of the artificial lung and by macroscopic and microscopic examination after the experiments. Artificial lung function, hemodynamics, hemogram, and platelet aggregation activity were well maintained in all groups. There was no plasma leakage from the artificial lung. Although several clots were observed in stagnant areas of the artificial lungs and circuits, there was no clot formation inside the artificial lung in any group. This highly biocompatible, heparin-bonded dense-membrane artificial lung performed well and safely during prolonged ECLA with blood clotting times less than 120 s.

Animals↗
PubMed2001

Increased levels of vascular endothelial growth factor and advanced glycation end products in aqueous humor of patients with diabetic retinopathy.

Clinical studies have shown a relationship between diabetic retinopathy and vascular endothelial growth factor (VEGF) levels in ocular fluid. Advanced glycation end products (AGEs) have been implicated in diabetes complications, including diabetic retinopathy. Nepsilon-(carboxymethyl) lysine (CML) is a glycoxidation product that may be a marker of oxidative stress. In this study, we used enzyme-linked immunosorbent assays to determine the levels of VEGF, non-CML AGE and CML in the aqueous humor and serum of 82 Japanese patients with type 2 diabetes and 60 non-diabetic subjects. VEGF, non-CML AGE, and CML concentrations in aqueous humor and serum were then compared with the severity of diabetic retinopathy. Immunohistochemical detection analysis of non-CML AGE and CML was also performed using retinal tissues from patients with progressive diabetic retinopathy. Aqueous levels of VEGF, non-CML AGE and CML increased along with the progression of diabetic retinopathy compared to age-matched controls. After coagulation therapy, the VEGF, non-CML AGE, and CML levels were significantly reduced. Immunostaining showed diffuse co-localization of non-CML AGE and CML around microvessels and in the glial cells of proliferative membranes from patients with progressive diabetic retinopathy. These findings suggest that glycation and glycoxidation reactions (or oxidation, as revealed by CML) may contribute to both the onset and progression of diabetic retinopathy.

Aged↗
PubMed2001

Laparoscopic ultrasonography for resection of insulinomas.

BACKGROUND: There have been few reports on the use of laparoscopic ultrasonography as an aid for the resection of insulinomas. In this study, we review our experience with laparoscopic ultrasonography for the intraoperative localization and resection of insulinomas. METHODS: We attempted laparoscopic resection of insulinomas in 7 patients (median age, 50 years) during a 4-year period. Preoperative imaging showed that 1 of the insulinomas was located in the head of the pancreas, 2 were located in the body, and 4 were located in the tail. RESULTS: We identified the insulinomas in all 7 patients with laparoscopic ultrasonography. In 6 of the patients, the insulinomas were laparoscopically resectable, either by enucleation (4 patients) or by resection of the pancreatic tail (2 patients). Conversion to laparotomy was necessary for the insulinomas in the head of the pancreas because they were close to the portal vein and the major pancreatic duct. All patients showed improvement in their hypoglycemia after the operations. Minor leakage of pancreatic juice occurred in 4 patients, and this was resolved with conservative treatment. CONCLUSIONS: Laparoscopic ultrasonography is useful for the intraoperative localization of insulinomas. Laparoscopy is a safe and feasible technique for resecting insulinomas located in the body or tail of the pancreas.

Adult↗
PubMed2001

Isolation of a putative receptor for KDEL-tailed cysteine proteinase (SH-EP) from cotyledons of Vigna mungo seedlings.

SH-EP is the major papain-type proteinase expressed in cotyledons of germinated Vigna mungo seeds. The proteinase possesses a KDEL sequence at the C-terminus although the mature form of SH-EP is localized in vacuoles. It has also been shown that the proform of SH-EP is accumulated at the edge or middle region of the endoplasmic reticulum, and the accumulated proSH-EP is directly transported to vacuoles via the KDEL-tailed cysteine proteinase-accumulating vesicle, KV. In this study, to address the transport machinery of proSH-EP through KV, putative receptor for proSH-EP was isolated from membrane proteins of cotyledons of V. mungo seedlings using a proSH-EP-immobilized column. The deduced amino acid sequence from cDNA to the protein revealed that the putative receptor for proSH-EP is a member of vacuolar sorting receptor, VSR, that is known to be localized in the Golgi-complex and/or clathrin coated vesicle. We carried out subcellular fractionation of cotyledon cells and subsequently conducted SDS-PAGE/immunoblotting and immunocytochemistry with anti-V. mungo VSR (VmVSR) or SH-EP antibody. The results showed that VmVSR is co-localized in the fraction of the gradient in which KV existed.

Amino Acid Sequence↗
PubMed2001

Involvement of gibberellins in expression of a cysteine proteinase (SH-EP) in cotyledons of Vigna mungo seedlings.

The expression of a papain-type proteinase, designated SH-EP, in cotyledons of Vigna mungo seedlings has been shown to require some factors in the embryonic axes. Gibberellin A1 (GA(1)) and GA(20) were identified by GC-MS in embryonic axes of V. mungo seedlings. The level of accumulation of SH-EP in cotyledons of V. mungo seedlings was greatly reduced by treatment of the seeds with uniconazole-P, an inhibitor for GA biosynthesis. The reduced level of accumulation of SH-EP in cotyledons by uniconazole-P was recovered by exogenous application of GA(1) and GA(20) to the seedlings.

Cotyledon↗
PubMed2001

Enhanced vascular permeability in solid tumor involving peroxynitrite and matrix metalloproteinases.

Peroxynitrite (ONOO(-)), which is generated from nitric oxide (NO) and superoxide anion (O(2)(.-)) under pathological conditions, plays an important role in pathophysiological processes. Activation of matrix metalloproteinases (MMPs) contributes to tumor angiogenesis and metastasis. NO mediates the enhanced vascular permeability and retention (EPR) effect in solid tumors, and ONOO(-)activates proMMP to MMP in vitro. In this study, we examined the role of ONOO(-)in the EPR effect in solid tumors and normal tissues as related to MMP activation. Authentic ONOO(-), at 50 nmol or higher concentrations, induced the enhanced vascular permeability in normal dorsal skin of mice. ONOO(-)scavengers ebselen and uric acid significantly suppressed the EPR effect in mouse sarcoma 180 (S-180) tumors. Indirect evidence for formation of ONOO(-)in S-180 and mouse colon adenocarcinoma (C-38) tumors included strong immunostaining for nitrotyrosine in the tumor tissue, predominantly surrounding the tumor vessels. MMP inhibitor BE16627B (66.6 mg / kg i.v., given 2 times) or SI-27 (10 mg / kg i.p., given 2 times) significantly suppressed the ONOO(-)-induced EPR effect in S-180 tumors and in normal skin. Soybean trypsin inhibitor (Kunitz type), broad-spectrum proteinase inhibitor ovomacroglobulin, and bradykinin receptor antagonist HOE 140 also significantly suppressed the ONOO(-)-induced EPR effect in normal skin tissues. These data suggest that ONOO(-)may be involved in and promote the EPR effect in tumors, which could be mediated partly through activation of MMPs and a subsequent proteinase cascade to generate potent vasoactive mediators such as bradykinin.

Adenocarcinoma↗
PubMed2001

Lunate plasty for Kienböck's disease: use of a pedicled vascularised radial bone graft combined with shortening of the capitate and radius.

We treated eight patients with Kienböck's disease (two patients each with stage 1, 2, 3a and 3b disease by Lichtman's classification) by removing a pedicled, vascularised bone segment from the dorsal aspect of the distal radius and engrafting it into the lunate. Additional shortening of the radius was performed in patients with the ulna-minus or null variant. Shortening of the capitate and capito-hamate fusion were also performed in patients with stage 3 disease. All patients were relieved of their wrist pain at rest and during movement, and the mean grip strength increased from 37% of that in the contralateral hand before surgery to 80% after surgery. The mean post-operative range of motion in the affected wrist was 92% of that in the opposite wrist in patients with stage 1 and 2 disease, and 53% in patients with stage 3 disease. Post-operative assessment revealed that four patients had excellent results, three had good results, and one had a fair result.

Adult↗
PubMed2001

Hepatectomy using the coagulating shears type of ultrasonically activated scalpel.

Since the ultrasonically activated scalpel (UAS) incorporates multiple functions, we have used it for hepatectomies. The present study discusses the noteworthy points and problems of use, and shows initial results. Intraoperative ultrasonography is an important tool for comprehending the positional relationship between the plane of division and the main blood vessels. It allows initial adjustment of coagulation and cutting effects according to the rigidity of the liver parenchyma by means of variable ultrasound levels and exchangeable blade tips, and offers good visibility of the cut surface in deep sites as long as adequate tension on the tissue and an upper position for the blade are maintained. 30 patients underwent hepatectomies using the UAS. The amount of blood loss for lobectomy was significantly less than that for partial lobectomy in normal livers in addition to a significant difference between normal and damaged livers in each group according to the extent of resection. There were no serious complications seen in all cases during the operation. The incidence of positive bile leakage was high. It is recommended that bile leakage testing be carried out as thoroughly as possible. There were 3 postoperative bile fistulas and 1 postoperative hemorrhage. In conclusion, although a dramatic improvement in blood loss and shortened operating time could not be obtained in all procedures, the safety and usefulness were demonstrated in lobectomy. The UAS can be considered as a surgical device that can contribute to the efficiency of hepatectomy, depending on the indications selected.

Blood Loss, Surgical↗
PubMed2001

Resistance to multiple agent chemotherapy including cisplatin after chronic low-dose oral etoposide administration in gestational choriocarcinoma.

Most patients with gestational trophoblastic disease in whom single-agent or even combination chemotherapy has failed can be cured with salvage chemotherapy including etoposide or platinum-based regimens. Here we report a rare case of uterine choriocarcinoma following a molar evacuation that seemed to develop during chronic low-dose oral administration of etoposide for approximately 16 months. Although the patient was expected to have a good chance of cure using combination chemotherapy, the lesion was resistant to multiple-agent chemotherapy including cisplatin.

Administration, Oral↗
PubMed2001

Expression of nm23-H1 in hydatidiform mole and its relationship with the development of postmolar disease.

The aim of the present study was to investigate the expression of nm23-H1 in human placenta, hydatidiform mole and choriocarcinoma cells. Nm23-H1 protein was localized in the cytotrophoblast, but not in the syncytiotrophoblast. In the hydatidiform mole cases with subsequent spontaneous remission, nm23-H1 mRNA levels were significantly lower than those in first-trimester placentas. However, its levels were elevated in the hydatidiform mole cases that progressed to persistent gestational trophoblastic disease and were comparable to those of first-trimester placentas, and they were further elevated in choriocarcinoma cells. The present data suggest an association of nm23-H1 for the proliferation activity of trophoblast, and its increased expression may influence the development of persistent trophoblastic disease.

Blotting, Northern↗
PubMed2001

Expression of matrix metalloproteinases in pigs with hyperoxia-induced acute lung injury.

The aim of this study was to determine the role of matrix metalloproteinases (MMPs) in the pathogenesis of acute lung injury induced by hyperoxia. Twenty-three pigs were exposed in sealed cages to >80% oxygen (for 24-120 h) or room air. Correlation between MMP-2/MMP-9 activity, measured by gelatin zymography in bronchoalveolar lavage fluid (BALF), and the histological findings and pathological parameters were examined in detail. Sources of these MMPs in the hyperoxic lung were analysed by immunohistochemistry. The histological progression of acute lung injury in this model ranged from the early exudative to the early proliferative phase of diffuse alveolar damage (DAD). MMP-2 and -9 activities were elevated under prolonged hyperoxic exposure. MMP-9 activity correlated significantly with the oxygen tension in arterial blood/inspiratory oxygen fraction, the lung wet-to-dry weight ratio, and the number of neutrophils in BALF, whereas MMP-2 activity did not correlate at all with these factors. MMP-9 activity correlated more closely with the pathological findings of DAD than did MMP-2 activity. Strong MMP-9 expression was observed in neutrophils, alveolar macrophages as well as alveolar lining epithelial cells. These results suggest that matrix metalloproteinase. which may derive from neutrophils recruited into airspaces, plays an important role in the pathogenesis of hyperoxic diffuse alveolar damage

Animals↗
PubMed2001

Erythromycin attenuates an experimental model of chronic bronchiolitis via augmenting monocyte chemoattractant protein-1.

The mechanisms underlying the therapeutic efficacy of erythromycin (EM) in diffuse panbronchiolitis (DPB) was investigated. For this purpose, an experimental rabbit model of DPB induced by Pseudomonas aeruginosa inoculation was employed. Daily administration of EM (3 mg x kg x day(-1)) led to an increase in the number of macrophages in bronchoalveolar lavage fluid (BALF) at an early phase, while reducing the size of granulomatous lesions at the late phase without affecting the number of viable bacteria recovered from the infected lung. Reverse transcriptase polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and immunohistochemical studies showed that monocyte chemoattractant protein (MCP)-1 was produced in both BALF and infected lung. EM treatment resulted in a significant increase in the level of MCP-1 in BALF, while reducing that of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-8. EM also increased MCP-1 messenger ribonucleic acid (mRNA) and protein expression in the infected lung. MCP-1 blockade abolished the protective effect of EM, as neutralization of MCP-1 with anti-MCP-1 antibodies reduced the EM-induced increase in the number of macrophages in BALF, and augmented size of the granulomatous lesions, as compared to control. The results of the present study suggest that erythromycin attenuates the pulmonary granuloma formation, at least in part, by increasing the production of monocyte chemoattractant protein-1.

Animals↗