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Biomedical subjects

Y Tsurumi

Publications and source records attributed to Y Tsurumi.

At least 19 recordsLinked to original sources
PubMed2006

Interacting molecule of AT1 receptor, ATRAP, is colocalized with AT1 receptor in the mouse renal tubules.

The renin-angiotensin system in the kidney plays a critical role in the regulation of renal hemodynamics and sodium handling through the activation of vascular, glomerular and tubular angiotensin II type 1 (AT1) receptor-mediated signaling. We previously cloned a molecule that specifically bound to the AT1 receptor and modulated AT1 receptor signaling in vitro, which we named ATRAP (for AT1 receptor-associated protein). The purpose of this study is to analyze the renal distribution of ATRAP and to examine whether ATRAP is co-expressed with the AT1 receptor in the mouse kidney. We performed in situ hybridization, Western blot analysis, and immunohistochemistry to investigate the expression of ATRAP mRNA and protein in the mouse kidney. The results of Western blot analysis revealed the ATRAP protein to be abundantly expressed in the kidney. Employing in situ hybridization and immunohistochemistry, we found that both ATRAP mRNA and the protein were widely distributed along the renal tubules from Bowman's capsules to the inner medullary collecting ducts. ATRAP mRNA was also detected in the glomeruli, vasculature, and interstitial cells. In all tubular cells, the ATRAP protein colocalized with the AT1 receptor. Finally, we found that the dietary salt depletion significantly decreased the renal expression of ATRAP as well as AT1 receptor. These findings show ATRAP to be abundantly and broadly distributed in nephron segments where the AT1 receptor is expressed. Furthermore, this is the first report demonstrating a substantial colocalization of ATRAP and AT1 receptor in vivo.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Chemical diversity in lipopeptide antifungal antibiotics.

In the course of screening for antifungal antibiotics, we have discovered a novel series of lipopeptide compounds structurally related to, but highly superior to, echinocandin B in terms of their water solubility due to the presence of a sulfate residue. These compounds, WF11899s, WF738s, WF14573s, WF16616 and WF22210, and their derivatives have diversity in their nuclear structures and acyl side chains. The producing strains were classified into two groups, the Coleomycetes group and the Hyphomycetes group. Compound FK463, a derivative of WF11899A, is currently in Phase 3 clinical development as a novel antifungal antibiotic.

Animals↗
PubMed2001

FR198248, a new anti-influenza agent isolated from Apsergillus terreus No 13830. I. Taxomony, fermentation, isolation, physico-chemical properties and biological activities.

A novel anti-influenza agent, FR198248, was isolated from the cultured broth of a fungal strain No.13830. The strain was identified as Aspergillus terreus from morphological characteristics. FR198248, a new type of hydroxyl benzaldehyde compound, showed antiinfluenza virus activity in Madin-Darby canine kidney (MDCK) cells in vitro. The mode of action of FR198248 against influenza virus A could be ascribed to an inhibitory effect on the stage of virus adsorption. Furthermore, FR198248 possessed potent in vivo anti-influenza activity in a murine model of respiratory tract infection.

Animals↗
PubMed2001

[Gene therapy for the treatment of hypertension].

Gene therapy for hypertension is very important for the next generation of antihypertensive drugs. Important question regarding vector-related limitations and suboptimal in vivo delivery systems will require expeditious attention for gene therapy to become a more widely applicable option in cardiovascular diseases including hypertension. However, the elucidation of molecular mechanisms of transcriptional activation of several important genes in the cardiovascular physiology enables us to develop clinical application of gene therapy for hypertension at the level of transcription factors. Recent studies showed that in vivo or ex vivo transfection of double-stranded oligodeoxynucleotides to block the binding of nuclear factors to specific cis-elements in the promoter regions of several genes resulted in inhibition of gene trans-activation and suppressed pathological changes in the cardiovascular system.

Angiotensinogen↗
PubMed2001

[Initial results and long-term outcome of percutaneous coronary intervention in patients with previous coronary artery bypass grafting].

OBJECTIVES: The incidence of percutaneous coronary intervention following bypass surgery(coronary artery bypass grafting: CABG) is not low, but the outcomes of patients requiring percutaneous coronary intervention after CABG are not well known. METHODS: From June 1970 to June 2000, 2,981 patients underwent CABG at our institute using 6,747 grafts including 2,875 saphenous vein graft(SVG), 3,042 internal thoracic artery(ITA), 706 gastro-epiploic artery(GEA), 122 radial artery(RA), and 2 others. Three hundred twenty-seven patients underwent subsequent percutaneous coronary intervention in 520 lesions(104 SVG, 97 ITA, 12 GEA, 8 RA, 299 native artery). The initial results and long-term outcome following percutaneous coronary intervention in these 520 consecutive procedures were evaluated retrospectively. RESULTS: Percutaneous coronary intervention to arterial grafts were performed mainly within the early post-operative period, whereas percutaneous coronary intervention to vein grafts had two periodic peaks in the early post-operative period and at 7 years after CABG. Procedural success rate of percutaneous coronary intervention was 90% for SVG, 81% for ITA, 58% for GEA, 88% for RA, and 87% for native arteries. Restenosis rate was 56% for SVG, 30% for ITA, 83% for GEA, 83% for RA, and 49% for native arteries. Cardiac events after percutaneous coronary intervention with previous CABG were greater in cases of ITA, followed by native arteries, SVG, GEA and RA(p = 0.0046). In the early post-operative period, there was no significant difference between ITA and SVG. In the chronic stage, the prognosis of cardiac events after PCI for SVG was worse than for ITA. CONCLUSIONS: Percutaneous coronary intervention after CABG requires strategic consideration based on target-specific initial results and long-term outcome.

Adult↗
PubMed2000

FR191512, a novel anti-influenza agent isolated from a fungus strain No.17415. I. Taxonomy, fermentation, isolation, physico-chemical properties and structure elucidation.

In the course of our screening for anti-influenza agents of microbial origin, FR191512 was isolated from the cultured broth of fungus strain No. 17415 as colorless powder. The structure of FR191512 was determined by several spectroscopic experiments as a novel polyphenolic compound. This compound showed potent antiviral activity against influenza A virus.

Antiviral Agents↗
PubMed2000

FR901469, a novel antifungal antibiotic from an unidentified fungus No.11243. II. In vitro and in vivo activities.

FR901469 is a water-soluble macrocyclic lipopeptidolactone (C71H116N14O23) that has inhibitory activity against 1,3-beta-glucan synthase and exhibits in vitro and in vivo antifungal activity against both Candida albicans and Aspergillus fumigatus. The MICs of FR901469 against Candida albicans FP633 and Aspergillus fumigatus FP1305 in a micro-broth dilution test were 0.63 and 0.16 microg/ml, respectively. FR901469 showed excellent efficacy by subcutaneous injection against both Candida albicans and Aspergillus fumigatus in a murine systemic infection mode, with ED50s of 0.32 and 0.2 mg/kg, respectively. This compound also showed potent anti-Pneumocystis activity in the nude mice model with experimental Pneumocystis pneumonia. The hemolytic activity of FR901469 towards mouse red blood cells, is about 30-fold weaker than that of amphotericin B.

Animals↗
PubMed1999

Clinical potential of intravascular ultrasound for physiological assessment of coronary stenosis: relationship between quantitative ultrasound tomography and pressure-derived fractional flow reserve.

BACKGROUND: Little is known regarding intravascular ultrasound (IVUS) criteria to determine the functional severity of coronary stenosis. Recently, fractional flow reserve (FFR) has emerged as a lesion-specific index of the functional severity of a coronary stenosis that is independent of systemic hemodynamic variability. The present study was undertaken to determine the IVUS parameters for the physiological severity of coronary stenosis. METHODS AND RESULTS: Fifty-one lesions in 42 patients were evaluated by means of quantitative coronary angiogram, IVUS, and intracoronary pressure measurements. The FFR was calculated as the ratio of the distal coronary pressure divided by the proximal coronary pressure under hyperemia. We considered a value of the FFR <0.75 as significant in determining inducible ischemia, according to the previous studies. The minimal luminal area (MLA) and the area stenosis were measured by IVUS. By regression analysis, the MLA showed a positive correlation with the FFR value (r(2)=0.62, P<0.0001). The area stenosis had a significant inverse correlation with the value of FFR (r(2)=0.60, P<0.0001). The IVUS thresholds that maximized the sensitivity and specificity were MLA <3.0 mm(2) (sensitivity, 83.0%; specificity, 92.3%) and area stenosis >0.6 (sensitivity, 92.0%; specificity, 88.5%). The combination of both criteria (MLA <3.0 mm(2) and area stenosis <0.6) without exception met a value of the FFR <0.75. CONCLUSIONS: Anatomic parameters obtained by IVUS showed a significant correlation to the FFR values. The present study demonstrated that the combination of the MLA and area stenosis measured by IVUS can be an anatomic predictor for the physiological impact of coronary epicardial stenosis.

Coronary Angiography↗
PubMed1999

Clinical and angiographic outcome of stenting following suboptimal results of percutaneous transluminal coronary angioplasty in small (<2.5 mm) coronary arteries.

The purpose of the present study was to evaluate the feasibility and efficacy of stenting following suboptimal percutaneous transluminal coronary angioplasty (PTCA) in angiographically small coronary arteries. The clinical and angiographic outcome of unplanned stenting in 33 patients with coronary arteries <2.5 mm in diameter was studied. Procedural success was achieved for 97.0% with a greater initial gain (1.79 +/- 0.60 vs. 1.34 +/- 0.58 mm, P < 0.05) and larger postprocedural minimal luminal diameter (2.19 +/- 0.43 vs. 1.57 +/- 0.57 mm, P < 0.001) than that in the size-matched elective PTCA patients. Trends toward a lower restenosis rate and a significant reduction in target lesion revascularization (7.1% vs. 41.9%, P < 0.01) were observed in the stented patients, suggesting the feasibility and efficacy of stenting following suboptimal PTCA in small coronary arteries. Cathet. Cardiovasc. Intervent. 47:269-276, 1999.

Aged↗
PubMed1999

[Significance of angiographic haziness at the distal stent edge: analysis by intravascular ultrasound and quantitative coronary angiography].

Haziness on coronary angiograms has been interpreted as thrombogenic morphologies such as dissection or thrombus. Haziness is often seen at distal sites following stent deployment. To clarify the pathophysiology of distal haziness of coronary stenting, we performed intravascular ultrasonography (3.5F, 30 MHz) after implantation of 48 Palmaz-Schatz stents in 45 patients. Haziness was defined visually as a reduction in contrast density or an indistinct vessel border. The luminal diameter and videodensitometry score were measured at the distal edge of the stent and distal adjacent segment by quantitative coronary angiography. Luminal diameter and lumen area were measured by intravascular ultrasound. The distal/in-stent ratio was calculated for each measurement to assess the magnitude of the vessel tapering and the reduction in contrast density. Haziness was found in 18 vessels. Qualitative intravascular ultrasound determined dissections (n = 5) and irregular shapes of the lumen compressed by heavy calcium (n = 3) in the hazy vessels. There were no specific morphologies in the other 10 cases. Distal/in-stent ratio of the videodensitometry score was significantly smaller in hazy vessels, but quantitative coronary angiography could not distinguish hazy arteries with dissection or calcium from arteries without specific morphologies. The distal/in-stent ratio of the lumen area (< 0.8) and lumen area at the distal segment (< 5 mm2) were markedly smaller in the 'hazy' group without specific morphologies. Dissection, heavy calcium, and luminal reduction can cause a hazy appearance at the distal stent edge. Quantitative coronary angiography could quantify the haziness, but could not distinguish the morphologies of the vessel wall. Only intravascular ultrasound could assess the pathophysiology of hazy vessels after coronary stenting.

Calcium↗
PubMed1998

Reduction of vein graft intimal hyperplasia and preservation of endothelium-dependent relaxation by topical vascular endothelial growth factor.

PURPOSE: Recent evidence suggests that vascular endothelial growth factor (VEGF), in addition to stimulating angiogenesis, also serves a repair/maintenance or survival function, modulating various aspects of endothelial cell function. This study was designed to examine the effect of VEGF pretreatment in a model of vein graft intimal hyperplasia. METHODS: Reversed jugular vein-to-common carotid artery interposition grafts were constructed in New Zealand White rabbits. White rabbits. Vein conduits were immersed in solution containing 500 micrograms rhVEGF165 or saline solution for 20 minutes before implantation. Twenty-eight days later the vein grafts and contralateral control jugular veins were harvested for either histologic or isometric tension studies. RESULTS: VEGF-treated vein grafts showed a 23% reduction in intimal area (0.76 +/- 0.07 mm2 vs 0.98 +/- 0.06 mm2; p = 0.028) and a 30% reduction in intimal thickness (62 +/- 6 microns vs 89 +/- 5 microns; p = 0.001) when compared with control grafts. After precontraction with norepinephrine, the maximal relaxation to acetylcholine (endothelium-dependent, receptor-mediated agonist) for control vein grafts was 0%, whereas for VEGF-treated vein grafts it was 25% +/- 9% (p < 0.05 vs control grafts). The maximal relaxation to the calcium ionophore A23187 (endothelium-dependent, receptor-independent agonist) was also greater in VEGF-treated grafts than in control grafts (172.3% +/- 19.4% vs 122.5% +/- 13.7%; p < 0.05). There was no difference in the response to sodium nitroprusside (endothelium-independent agonist) between the two groups. CONCLUSIONS: A single topical application of VEGF before implantation reduces intimal hyperplasia and improves endothelial function in a rabbit vein graft model. Further evaluation of this simple strategy to improve vein graft patency appears warranted.

Acetylcholine↗
PubMed1998

[Current approaches to restenosis after coronary interventions].

Restenosis after balloon coronary angioplasty (PTCA) is a major limitation of coronary intervention. Multicenter study performed in seven hospitals in Japan showed restenosis rate after PTCA steadily increased from 34% in 1985 to 45% in 1993. To overcome this problem, several new devices have been developed. Currently, directional coronary atherectomy, stent and Rotablator are regarded as promising approaches. After the publication of the results of two large studies that first demonstrated a favorable effect of stent restenosis, the number of stent implantation has dramatically increased. In 1995, the ratio of PTCA to stent implantation was 100:55 in above seven hospitals. The restenosis rate was lower in stent patients compared to PTCA (28% vs. 33%). Interestingly, the restenosis rate of PTCA has decreased after stent became available, which indicates the importance of case selection.

Angioplasty, Balloon, Coronary↗
PubMed1997

Treatment of acute limb ischemia by intramuscular injection of vascular endothelial growth factor gene.

BACKGROUND: Ischemic skeletal muscle has been shown to be advantageous for taking up and expressing genes transferred in the form of naked plasmid DNA. Therefore, acutely ischemic skeletal muscle may represent a potential target for IM gene therapy with naked DNA. Accordingly, we investigated the impact of IM injection of plasmid DNA encoding the secreted angiogenic growth factor, vascular endothelial growth factor (VEGF), on collateral vessel development in an animal model of acute hindlimb ischemia. METHODS AND RESULTS: After ligation of distal external iliac artery in New Zealand White rabbits, we directly injected 500 microg of phVEGF165 into the ischemic thigh muscles. At 30 days posttransfection, VEGF-transfected animals had more angiographically recognizable collateral vessels (angiographic score=0.72+/-0.06 versus 0.48+/-0.10; P<.01) as well as histologically assessed capillaries (248+/-37 versus 180+/-32/mm2, P<.01) compared to controls. Hemodynamic deficit was less severe in VEGF-transfected animals by calf systolic blood pressure ratio (0.80+/-0.09 versus 0.56+/-0.10, P<.01) and by flow to the ischemic limb measured with Doppler guidewire (resting flow=22+/-5 versus 14+/-4; P<.01; hyperemic flow=59+/-17 versus 39+/-12 mL/min; P<.05). Human VEGF mRNA was expressed in the transfected ischemic muscles as long as 14 days after gene transfer. Based on reporter plasmid expression, transfection efficiency was sixfold higher in ischemic muscles than in nonischemic control muscles. CONCLUSIONS: These results suggest the feasibility of employing direct IM transfer of naked VEGF plasmid DNA to optimize treatment of acute limb ischemia.

Acute Disease↗
PubMed1997

Histochemical staining following LacZ gene transfer underestimates transfection efficiency.

Analysis of LacZ gene expression is conventionally inferred from blue staining that results from exposure of the transfected cells or tissue to the substrate 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). Such histochemical staining reports not whether the gene product is present or absent, but where it is active. We investigated the hypothesis that identification of activity, as opposed to presence, of the enzyme underestimates gene expression following LacZ gene transfer. Under conditions optimized for in vitro histochemistry, up to 20% of cells stably transfected with nls-LacZ remained unstained by X-Gal. In contrast, immunostaining with a monoclonal or a polyclonal anti-beta-galactosidase (beta-Gal) antibody positively stained 99% of the cell nuclei. Following in vivo transfection of naked DNA encoding for nls-LacZ, X-Gal staining disclosed 2.7 +/- 1.7 positive nuclei per LacZ-transfected animal, or a transfection efficiency of 0.015%. In contrast, immunohistochemical staining disclosed 118 +/- 32.7 positive nuclei per transfected animal, yielding a transfection efficiency of 0.64% (p < 0.0001 versus X-Gal staining). Thus, 42.9 times more positive cells were detected by antibody than X-Gal staining. Finally, LacZ gene expression following intramuscular gene transfer with an adenoviral vector was observed in 7.6% of skeletal muscle cells assessed with X-Gal; anti-beta-Gal antibody identified 21.8% of cells as being successfully transfected (p < 0.0001). Thus, X-Gal histochemistry following gene transfer of constructs encoding LacZ may underestimate the anatomic extent of gene expression. The superior sensitivity of immunostaining suggests that anti-beta-Gal antibody represents the preferred analytical tool for light microscopic evaluation of LacZ gene transfer.

Adenoviridae↗
PubMed1997

Reciprocal relation between VEGF and NO in the regulation of endothelial integrity.

Balloon angioplasty disrupts the protective endothelial lining of the arterial wall, rendering arteries susceptible to thrombosis and intimal thickening. We show here that vascular endothelial growth factor (VEGF), an endothelial cell mitogen, is upregulated in medial smooth muscle cells of the arterial wall in response to balloon injury. Both protein kinase C (PKC) and tyrosine kinase pp60src mediate augmented VEGF expression. In contrast, nitric oxide (NO) donors inhibit PKC-induced VEGF upregulation by interfering with binding of the transcription factor activator protein-1 (AP-1) to the VEGF promoter. Inhibition of VEGF promoter activation suggests that NO secreted by a restored endothelium functions as the negative feedback mechanism that downregulates VEGF expression to basal levels. Administration of a neutralizing VEGF antibody impaired reendothelialization following balloon injury performed in vivo. These findings establish a reciprocal relation between VEGF and NO in the endogenous regulation of endothelial integrity following arterial injury.

Animals↗
PubMed1997

Arterial gene therapy: a molecular biological perspective for the treatment of arterial ischemia.

Since most cells do not naturally incorporate foreign DNA, strategies for arterial gene transfer have generally relied on agents designed to augment cellular DNA uptake such as liposomes, viral vectors, and protein conjugates. However, even when DNA has been successfully introduced into a cell, the likelihood of gene expression remains uncertain because the transgene has to escape lysosomal degradation, be transferred to the nucleus for transcription of mRNA, and be exported to the cytoplasm for translation and/or post-translation modification of the protein product. Transfection efficiency represents the final index of this regulatory sequence. The extent to which this compromises human gene therapy for cardiovascular disease depends in part on the presence or absence of a signal sequence permitting active secretion of the gene product. The implication of these issues is discussed with regard to restenosis and angiogenesis.

Animals↗
PubMed1996

Direct intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor augments collateral development and tissue perfusion.

BACKGROUND: Striated muscle has been shown to be capable of taking up and expressing foreign genes transferred in the form of naked plasmid DNA, although typically with a low level of gene expression. In the case of genes that encode secreted proteins, however, low transfection efficiency may not preclude bio-activity of the secreted gene product. Accordingly, we investigated the hypothesis that intramuscular (IM) gene therapy with naked plasmid DNA encoding vascular endothelial growth factor (VEGF) could augment collateral development and tissue perfusion in an animal model of hindlimb ischemia. METHODS AND RESULTS: Ten days after ischemia was induced in one rabbit hindlimb, 500 micrograms of phVEGF165, or the reporter gene LacZ, was injected IM into the ischemic hindlimb muscles. Thirty days later, angiographically recognizable collateral vessels and histologically identifiable capillaries were increased in VEGF transfectants compared with controls. This augmented vascularity improved perfusion to the ischemic limb, documented by a superior calf blood pressure ratio for phVEGF165 (0.85 +/- 0.05) versus controls (0.64 +/- 0.05, P < .01), improved blood flow in the ischemic limb (measured with an intra-arterial Doppler wire) at rest (phVEGF165 = 21.3 +/- 3.9 mL/min, control = 14.6 +/- 1.6 mL/min, P < .01) and after a vasodilator (phVEGF165 = 54.2 +/- 12.0 mL/min, control = 37.3 +/- 8.9 mL/min, P < .01) and increased microspheres in the adductor (phVEGF165 = 4.3 +/- 1.6 mL.min-1.100 g of tissue-1, control = 2.9 +/- 1.2 mL.min-1.100 g of tissue-1, P < .05) and gastrocnemius (phVEGF165 = 3.9 +/- 1.0 mL.min-1.100 g of tissue-1, control = 2.8 +/- 1.4 mL.min-1.100 g of tissue-1, P < .05) muscles of the ischemic limb. CONCLUSIONS: Ischemic skeletal muscle represents a promising target for gene therapy with naked plasmid DNA. IM transfection of genes encoding angiogenic cytokines, particularly those that are naturally secreted by intact cells, may constitute an alternative treatment strategy for patients with extensive peripheral vascular disease in whom the use of intravascular catheter-based gene transfer is compromised and/or prohibited.

Animals↗