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T Okamoto

Publications and source records attributed to T Okamoto.

At least 37 records · Page 2Linked to original sources
PubMed2003

Pathology of sporotrichosis in 10 cats in Rio de Janeiro.

Ten cats with sporotrichosis were examined clinically and pathologically. They were in very poor general condition, and had widespread ulcerated cutaneous lesions and respiratory signs. Gross internal abnormalities were found only in the lungs and lymph nodes. Histologically, an inflammatory infiltrate and yeast-like structures were observed in the skin, lungs, liver and lymph nodes. The spleen was congested and contained fungal elements. No microscopical changes were observed in the pancreas, kidneys and heart. Sporothix schenckii was isolated from all the skin samples and nasal swabs obtained in vivo, and from all the samples of lung, liver, spleen, lymph nodes, heart and kidney taken postmortem.

Animals↗
PubMed2003

Pigment epithelium-derived factor prevents advanced glycation end products-induced monocyte chemoattractant protein-1 production in microvascular endothelial cells by suppressing intracellular reactive oxygen species generation.

AIMS/HYPOTHESIS: Monocytes and macrophages accumulate in the lesion of the diabetic retina, which are most likely involved in the progression of diabetic retinopathy. The levels of monocyte chemoattractant protein-1 (MCP-1) in vitreous fluids were associated with the severity of proliferative diabetic retinopathy. Recently, pigment epithelium-derived factor has been shown to be involved in the pathogenesis of proliferative diabetic retinopathy. However, a role of pigment epithelium-derived factor in monocyte recruitments in diabetic retinopathy remains to be elucidated. In this study, we investigated effects of purified pigment epithelium-derived factor on AGE-induced reactive oxygen species generation, MCP-1 mRNA up-regulation and protein production in human cultured microvascular endothelial cells. METHODS: The intracellular formation of reactive oxygen species was measured using the fluorescent probe CM-H(2)DCFDA. MCP-1 gene expression was analysed in quantitative reverse transcription-polymerase chain reaction. Monocyte chemoattractant protein-1 production by microvascular endothelial cells was measured with an ELISA system. RESULTS: AGE increased intracellular reactive oxygen species generation in microvascular endothelial cells. Pigment epithelium-derived factor inhibited the AGE-induced reactive oxygen species generation in a dose-dependent manner. An anti-oxidant, N-acetylcysteine, or pigment epithelium-derived factor completely prevented the AGE-induced up-regulation of MCP-1 mRNA contents as well as protein production in microvascular endothelial cells. CONCLUSIONS/INTERPRETATIONS: Pigment epithelium-derived factor inhibits the AGE-induced reactive oxygen species generation and the subsequent increase in MCP-1 production in microvascular endothelial cells. Our study suggests that substitution of pigment epithelium-derived factor could prevent the progression of diabetic retinopathy by attenuating the deleterious effects of AGE.

Cells, Cultured↗
PubMed2003

Can we identify novel angiogenesis inhibitors from cultured embryonic cells?

The first vascular structures in embryos are formed by vasculogensis, the de novo formation of blood vessels from angioblasts. However, angiogenesis, the sprouting of capillaries from pre-existing blood vessels, are also involved in the development of embryonic vascular system in certain organs, such as the kidney or the brain. These facts led us to speculate that embryonic tissues could produce potent angiogenesis inhibitors as well to refine the primitive vascular development. In the present study, we found that two different types of cultured human embryonic cells, 293T and WI-38, produced soluble factors that completely inhibited angiogenic effects of vascular endothelial growth factor on microvascular endothelial cells. Since angiogenesis is related to various pathological states, including tumor growth and metastasis and diabetic retinopathy, to identify novel potent angiogenesis inhibitors from cultured embryonic cells by differential display techniques or DNA microarray technology might be a valuable strategy to develop a novel therapeutic approach.

Angiogenesis Inhibitors↗
PubMed2003

Polymorphisms of sorbitol dehydrogenase (SDH) gene and susceptibility to diabetic retinopathy.

The polyol pathway consists of two enzymes aldose reductase (AR) and sorbitol dehydrogenase (SDH); the former is the first enzyme in the polyol pathway, that catalyzes the reduction of glucose to sorbitol, the latter is the second one, that converts sorbitol to fructose using by NAD(+) as a cofactor. We along with others have recently found that SDH activity, the second step in the polyol pathway, might make a greater contribution to the etiology of diabetic retinopathy than does the first step involving AR. In this paper, we propose a novel hypothesis that polymorphisms of SDH gene may be correlated with SDH gene expression levels in diabetic retinas, thus being a valuable genetic marker for diabetic retinopathy.

Aldehyde Reductase↗
PubMed2003

Endothelial damage caused by cytomegalovirus and human herpesvirus-6.

Infection with cytomegalovirus (CMV) or human herpesvirus-6 (HHV-6) may have a role in vascular endothelial damage after bone marrow transplantation (BMT). In total, 41 patients who underwent BMT were classified into four groups (12, 10, 7, and 12 patients who were infected with both CMV and HHV-6, CMV alone, HHV-6, and neither virus, respectively). Levels of thrombomodulin, plasminogen activator inhibitor-1, and cyclic GMP were 7.5+/-1.7 FU/ml, 76.4+/-24.1 ng/ml, and 9.51+/-1.1 pmol/ml, respectively, in the patients with both viruses, while the respective values were 2.9+/-0.67 FU/ml, 33.8+/-8.09 ng/ml, and 2.90+/-1.4 pmol/ml in patients infected with CMV alone, 4.8+/-0.96 FU/ml, 47.7+/-9.21 ng/ml, and 5.48+/-0.55 pmol/ml in patients with HHV-6 alone, and 1.6+/-0.39, 17.5+/-7.88 ng/ml, and 0.45+/-0.3 in those with neither virus. All three markers were significantly higher in the three groups with at least one virus than in the uninfected patients (P<0.05), and were also higher in patients with HHV-6 alone than in those with CMV alone (P<0.05). These results suggest that infection by CMV or HHV-6 causes vascular endothelial injury, with HHV-6 having a stronger effect than CMV, and combined infection having a stronger effect than either virus alone. Such viral infection may be a cause of thrombotic microangiopathy after BMT.

Acyclovir↗
PubMed2003

Influence of Helicobacter pylori on platelets after bone marrow transplantation from unrelated donors.

This study was performed to clarify the influence of Helicobacter pylori on the platelet count in patients undergoing bone marrow transplantation (BMT) from unrelated donors. Of 23 consecutive patients undergoing BMT from unrelated donors, the H. pylori antibody test did not change from before conditioning until recovery of the platelet count in 15 patients. These patients were classified into H. pylori antibody-positive (n=8) and -negative (n=7) groups. In the H. pylori antibody-positive group, the platelet count exceeded 20 x 10(9)/l significantly faster after BMT, than in the H. pylori antibody-negative group. When myelosuppression was most severe, the interleukin-6 (IL-6) level was significantly higher in the positive group than in the negative group (67.0+/-10.6 vs 9.9+/-2.4 pg/ml, P<0.05). In addition, the thrombopoietin level was significantly lower in the positive group than in the negative (510.1+/-313.9 vs 3209.1+/-2006.7 pg/ml, P<0.01). These data suggest that H. pylori infection accelerates recovery of the platelet count after BMT from unrelated donors, possibly by stimulating IL-6 production.

Adult↗
PubMed2003

Prognostic value of cyclic GMP in patients undergoing allogeneic bone marrow transplantation after conditioning with total body irradiation.

This study was performed to investigate whether measurement of cyclic GMP (cGMP), a marker for nitric oxide production, before and after allogeneic bone marrow transplantation (BMT) with total body irradiation (TBI) conditioning was of prognostic value. cGMP levels were monitored in 23 consecutive patients who received TBI as conditioning for BMT, and were compared with the outcome. cGMP became positive during the aplastic phase after BMT in 12 patients. In nine of these 12 patients, cGMP level decreased during the recovery phase. Eight of the nine patients survived, one dying after relapse. In three other patients, the cGMP level continued to increase even during the recovery phase and they died of severe complications. cGMP became positive on day 0 of BMT and during the leukocyte recovery phase after BMT in two and seven of the 23 patients, respectively. Subsequently, all patients died of severe complications. The two patients who were negative for cGMP both before and after BMT survived without complications. These results suggest that monitoring cGMP from early after BMT may be useful for predicting outcome and that it may be a useful prognostic marker.

Adolescent↗
PubMed2003

Immature dendritic cell/tumor cell fusions induce potent antitumour immunity.

BACKGROUND: Maturation of dendritic cells (DCs) is important to induce antigen-specific antitumour immunity in cancer immunotherapy with antigen-loaded DCs. However, DCs from tumour-bearing hosts are immature and functionally defective for antigen presentation. We examined whether DCs from tumour-bearing mice could be an effective part of a DC/tumour cell fusion vaccine. MATERIALS AND METHODS: Dendritic cells from healthy (DC-Hs) or MC38 tumour-bearing mice (DC-TBs) were examined for endocytotic capacity of FITC-labelled dextran, antigen-presenting capacity in allogeneic mixed leucocyte reaction (allo-MLR) and expression of I-Ab, CD80, and CD86. Fusion cells (FCs) of DC-Hs or DC-TBs and MC38 cells (FC-Hs or FC-TBs) were generated by treatment with polyethylene glycol (PEG). Mice vaccinated with FC-Hs or FC-TBs were studied for cytolytic activity of splenocytes and suppressive activity against established MC38 pulmonary metastases. RESULTS: Dendritic cell-TBs showed higher endocytotic capacity and lower antigen-presenting capacity than did DC-Hs, results indicating that DC-TBs are more immature and functionally defective for antigen presentation than are DC-Hs. Expression of surface molecules, however, was almost same between DC-Hs and DC-TBs. Splenocytes from mice immunized with FC-Hs or FC-TBs induced the same high cytolytic activity against MC38 cells. Vaccination of mice with FC-Hs or FC-TBs resulted in the same significant suppressive effect against established pulmonary metastases of MC38. CONCLUSION: Dendritic cells from tumour-bearing mice, despite being functionally defective, are effective vehicles for immunotherapy using DC/tumour cell fusion vaccines.

Animals↗
PubMed2003

Numerical studies of optical switching and optical bistability phenomena of nano- or meso-size spheres.

We propose the use of numerical calculations of the optical response of nonlinear Kerr-spheres, modifying the Mie theory. As a numerical example, we use a CuCl sphere coated with a Kerr-nonlinear sphere, taking into account the excitation of the Z3-exciton. The results clearly show that optical bistable and/or optical switching devices can be realized on a nano- and meso-size scale when the real part of the dielectric constant of CuCl is negative.

Journal Article↗
PubMed2003

Optical switching due to whispering gallery modes in dielectric microspheres coated by a Kerr material.

We numerically evaluated the optical responses of a nonlinear microsphere put on prisms, i.e. in prism-coupling geometry where the incident light excites the WGM through near-field coupling. As numerical calculations, we employed the finite-difference time-domain method taking into account Kerr nonlinearity. The sphere was coated by a Kerr material with 160 nm thick. The third-order nonlinear susceptibility of the Kerr material chi(3) was assumed to be 7 x 10(-14)[m(2) V(-2)]. The diameter of the sphere was assumed to be 1 micro m. The numerical results have shown that the control and/or the signal lights can induce the optical switching-like variation in the reflectance. Such a nonlinear response of the sphere has been interpreted by the variation in the dielectric constant of the sphere due to a Kerr nonlinearity.

Journal Article↗
PubMed2003

Impairments and prognostic factors for survival in patients with idiopathic pulmonary fibrosis.

The aim of the present study was to evaluate exercise limiting factors using cardiopulmonary exercise testing (CPET) in patients with idiopathic pulmonary fibrosis (IPF), and to investigate whether these parameters are related to survival after CPET. We evaluated 41 patients with IPF (mean 68.2 years, 27 male) who performed CPET. The exercise capacity in patients with IPF was limited more strongly by gas exchange and/or ventilatory impairments, compared with cardiac impairment. Using univariate analysis, the severity of exercise-induced hypoxemia (EIH) evaluated by deltaPaO2/deltaVO2 (PaO2-slope), oxygen uptake at maximum exercise, oxygen pulse at maximum exercise, ventilatory equivalent for carbon dioxide at maximum exercise and age were significantly related to the survival rate. Interestingly, the PaO2-slope was most closely correlated with the survival rate using multiple analysis with a stepwise evaluation. Nevertheless, PaO2 at rest and at maximum exercise were not factors influencing survival. In patients with IPF, CPET can simultaneously evaluate the ability of both the cardiovascular and respiratory systems, and should be available so that parameters can be derived to make the necessary prognostic estimations, with the most useful parameter being the degree of EIH as represented by the PaO2-slope.

Aged↗
PubMed2003

Haematogenous spread of Sporothrix schenckii in cats with naturally acquired sporotrichosis.

The recovery of Sporothrix schenckii from blood samples is rare, and the diagnosis of systemic sporotrichosis is usually made at necropsy. In this report, S schenckii was isolated from two or more internal organs of nine necropsied cats with naturally acquired sporotrichosis. Haematogenous spread was demonstrated in vivo by the isolation of S schenckii from the peripheral blood of 17 (n = 49, 34.4 per cent) cats. Feline leukaemia virus (FeLV) was not detected, and co-infection with feline immunodeficiency virus (FIV), observed in nine cases (n = 43, 20.9 per cent), apparently did not affect the isolation of S schenckii from peripheral blood or from the internal organs.

Animals↗
PubMed2003

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion.

BACKGROUND: In recent years, there has been an increasing number of cases of early gastric cancer (T1, NX) with intramucosal invasion, which are untreatable by surgical or endoscopic mucosal resection (EMR) because of their high risk. Currently, no adequate treatment is available for such patients. AIM: The main objective of this study was to evaluate whether argon plasma coagulation (APC) is an effective and safe modality for treating early gastric cancer untreatable by surgical resection or EMR. METHODS: The study group comprised 20 men and seven women diagnosed with gastric cancer with intramucosal invasion who were considered poor candidates for surgical resection or EMR due to risk factors such as severe cardiac failure or thrombocytopenia. Irradiation conditions for APC treatment were determined using swine gastric mucosa. We used an argon gas flow of 2 l/min at a power setting of 60 W and a maximum irradiation time of 15 s/cm(2). The follow up period of the 27 patients ranged from 18 to 49 months (median 30 months). RESULTS: All lesions were irradiated easily, including areas anatomically difficult for EMR such as the gastric cardia or the posterior wall of the upper gastric body. In 26 of 27 patients (96%) there was no evidence of recurrence during the follow up period (median 30 months). One patient showed recurrence six months after the treatment but was successfully retreated. No serious complications were found in any of the 27 patients but three patients (11%) experienced a feeling of abdominal fullness. INTERPRETATION: APC is a safe and effective modality for treatment of early gastric cancer with intramucosal invasion untreatable by surgical resection or EMR. However, further observations are necessary to determine the long term prognosis of patients undergoing this treatment.

Adenocarcinoma↗
PubMed2003

Angiotensin II-type 1 receptor interaction upregulates vascular endothelial growth factor messenger RNA levels in retinal pericytes through intracellular reactive oxygen species generation.

The renin-angiotensin system has been implicated in the development and progression of atherosclerosis, thereby contributing to adverse cardiovascular events. However, its role in diabetic retinopathy remains to be elucidated. Since pericyte loss and dysfunction have been considered as one of the characteristic changes of the early phase of diabetic retinopathy, we investigated the effects of angiotensin II (Ang II) on the growth and function of bovine cultured retinal pericytes. Ang II stimulated intracellular reactive oxygen species (ROS) generation in pericytes in a dose-dependent manner. Telmisartan, a newly developed Ang II type 1 receptor antagonist, completely inhibited ROS generation in pericytes induced by Ang II. Ang II decreased DNA synthesis in pericytes, which was significantly prevented by an antioxidant N-acetylcysteine. Furthermore, telmisartan or N-acetylcysteine were found to completely inhibit the Ang II-induced upregulation of vascular endothelial growth factor messenger RNA levels in pericytes. The present results suggest that Ang II-type 1 receptor interaction could induce pericyte loss and dysfunction through intracellular ROS generation, thus being involved in the development and progression of diabetic retinopathy.

Acetylcysteine↗
PubMed2003

[Pulmonary thromboembolism after videothoracoscopic excision of a mediastinal tumor; report of a case].

We experienced a case of pulmonary thromboembolism after videothoracoscopic excision of a mediastinal tumor. A 57-year-old woman underwent videothoracoscopic excision of an upper mediastinal tumor, which was pathologically diagnosed as neurilemmoma. On the first postoperative day, she suddenly suffered from fatigue and blood-gas analysis showed hypoxemia. No abnormal shadow was seen on chest X-ray. Lung perfusion scintigram showed multiple embolism. She was treated with anticoagulants and recovered well. We should pay attention to the possibility of pulmonary thromboembolism after video-assisted thoracic surgery as well as thoracotomy, especially when patients have risk factors for pulmonary thromboembolism.

Anticoagulants↗
PubMed2003

Angiotensin II stimulates platelet-derived growth factor-B gene expression in cultured retinal pericytes through intracellular reactive oxygen species generation.

Platelet-derived growth factor-BB (PDGF-BB) is a potent mitogen and chemoattractant for microvascular endothelial cells and glial cells in the retina and is thus involved in the development of proliferative diabetic retinopathy. However, relatively little is known about the regulation of PDGF-B gene expression in retinal cells. In this study, we cloned partial complementary DNAs (cDNAs) encoding bovine PDGF-B and examined the effects of angiotensin II (Ang II), which is also implicated in the pathogenesis of diabetic retinopathy, on PDGF-B gene expression in bovine cultured retinal pericytes. Ang II was found to up-regulate PDGF-B messenger RNA (mRNA) levels in bovine retinal pericytes. Telmisartan, a newly developed Ang II type 1 receptor antagonist, or an antioxidant N-acetylcysteine significantly inhibited PDGF-B gene induction in Ang II-exposed pericytes. The present results suggest that Ang II-type 1 receptor interaction could stimulate PDGF-B gene expression in cultured retinal pericytes through intracellular reactive oxygen species generation and could thus be involved in the progression of diabetic retinopathy.

Acetylcysteine↗