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Toru Kita

Publications and source records attributed to Toru Kita.

154 records · Page 9Linked to original sources
PubMed2002

Junctional adhesion molecules and interendothelial junctions.

Similar to epithelia, endothelial cells are linked to each other via intercellular junctional complexes including gap junctions, adherens junctions and tight junctions. While polarized epithelial cells show a high degree of spatial sorting of junctional complexes, endothelia organize their junctions randomly. For this reason the nature of endothelial contacts may be highly adaptable to the need of permeability and leukocyte transmigration. For instance, high endothelial venules (HEVs) in lymphoid organs, where lymphocytes continuously exit the bloodstream, generally show more leaky contacts than brain with its impermeable blood-brain barrier. We recently identified an Ig superfamily molecule named JAM-2 which is specifically expressed in junctions of lymphatic endothelial cells and HEVs. We showed that JAM-2 belongs to the novel CTX molecular family and we now cloned the human equivalent of JAM-2. The presence of JAM-2 at sites of constitutive lymphocyte circulation argues for a role of this molecule in facilitating transmigration. This is supported by the increased transmigration in vitro across endothelial cells overexpressing JAM-2 at intercellular contacts.

Amino Acid Sequence↗
PubMed2002

Mouse model of cerebral aneurysm: experimental induction by renal hypertension and local hemodynamic changes.

BACKGROUND AND PURPOSE: Rupture of cerebral aneurysm (CA) is the major cause of subarachnoid hemorrhage. Molecular mechanisms of this disease, however, remain unknown. To make possible genetic analysis of CA formation with genetically altered mice, we have successfully established a mouse model of saccular CA that recapitulates the essential features of human saccular CA. METHODS: In C57black/6 male mice, various stages of CAs were experimentally induced at the right anterior cerebral artery-olfactory artery bifurcations by ligations of left common carotid arteries and posterior branches of bilateral renal arteries with high salt diet. Both light and electron microscopic studies were performed with the longitudinal sections of anterior cerebral artery-olfactory artery bifurcations. RESULTS: In the treated group, various aneurysmal changes were detected in 14 of 18 mice. On the other hand, in the control group, no aneurysmal changes were found in 15 mice. In microscopic studies, aneurysmal changes were shown to include mainly fragmentation of internal elastic lamina, thinning of the smooth muscle cell layer, and degeneration of adventitial tissue, which were very similar to critical changes in human saccular CA. CONCLUSIONS: This mouse model of CA will be useful for studying the effects of complex determinants on CA formation and makes it possible to understand the pathogenesis of CA at the molecular level.

Animals↗
PubMed2002

Essential role of Gas6 for glomerular injury in nephrotoxic nephritis.

Growth-arrest specific gene 6 (Gas6) is a vitamin K-dependent growth factor for mesangial and epithelial cells. To investigate whether Gas6 is essential for progressive glomerular injury, we constructed Gas6(-/-) mice and examined the role of Gas6 in accelerated nephrotoxic nephritis (NTN), a model of progressive glomerulonephritis. We found less mortality and proteinuria in Gas6(-/-) mice than in wild-type mice following injection of nephrotoxic serum. Glomerular cell proliferation, glomerular sclerosis, crescent formation, and deposition of fibrin/fibrinogen in glomeruli were also reduced in Gas6(-/-) mice. Furthermore, administering Gas6(-/-) mice recombinant wild-type Gas6, but not Gas6 lacking a previously characterized N-terminal gamma-carboxyl group, induced massive proteinuria, glomerular cell proliferation, and glomerulosclerosis, comparable to responses seen in wild-type mice. These data indicate that Gas6 induces glomerular cell proliferation in NTN and suggest that this factor contributes to glomerular injury and the progression of chronic nephritis.

Animals↗
PubMed2002

Large scale cohort study of the relationship between serum cholesterol concentration and coronary events with low-dose simvastatin therapy in Japanese patients with hypercholesterolemia.

Hyperlipidemia is a well-established risk factor for primary coronary heart disease (CHD). Although simvastatin is known to lower serum lipid concentrations, the protective effect of such lipid-lowering therapy against primary CHD has not been established in Japanese patients with hypercholesterolemia. The Japan Lipid Intervention Trial was a 6-year, nationwide cohort study of 47,294 patients treated with open-labeled simvastatin (5-10 mg/day) and monitored by physicians under standard clinical conditions. The aim of the study was to determine the relationship between the occurrence of CHD and the serum lipid concentrations during low-dose simvastatin treatment. Simvastatin reduced serum concentrations of total cholesterol (TC), low-density lipoprotein- cholesterol (LDL-C) and triglyceride (TG), by 18.4%, 26.8% and 16.1% on average, respectively, during the treatment period. The risk of coronary events was higher when the average TC concentration was > or =240 mg/dl and the average LDL-C concentration was > or =160 mg/dl. The incidence of coronary events increased in the patients with TG concentration > or =300 mg/dl compared with patients with TG concentration <150 mg/dl. The high-density lipoprotein cholesterol (HDL-C) inversely correlated with the risk of coronary events. The J-curve association was observed between average TC or LDL-C concentrations and total mortality. Malignancy was the most prevalent cause of death. The health of patients should be monitored closely when there is a remarkable decrease in TC and LDL-C concentrations with low-dose statin. A reasonable strategy to prevent coronary events in Japanese hypercholesterolemic patients without prior CHD under low-dose statin treatment might be regulating the serum lipid concentrations to at least <240 mg/dl for TC, <160 mg/dl for LDL-C, <300 mg/dl for TG, and >40 mg/dl for HDL-C.

Adult↗
PubMed2002

Large scale cohort study of the relationship between serum cholesterol concentration and coronary events with low-dose simvastatin therapy in Japanese patients with hypercholesterolemia and coronary heart disease: secondary prevention cohort study of the Japan Lipid Intervention Trial (J-LIT).

Hyperlipidemia is primarily implicated in the progression of coronary heart disease (CHD) and its treatment is essential for patients with a history of CHD. Statins such as simvastatin, the lipid-lowering agents, are well-known for their ability to normalize patient's serum lipid levels. The Japan Lipid Intervention Trial study of simvastatin is the first nationwide investigation of the relationship between serum lipid levels and the development of CHD in Japanese patients with hypercholesterolemia. Of 5,127 patients, exclusively with a history of documented CHD at enrollment, 4,673 were treated with open-labeled simvastatin at an initial dose of 5-10 mg/day and were monitored for 6 years. The risk of coronary events tended to be higher in patients with a serum total cholesterol (TC) > or =240 mg/dl compared with total cholesterol <240 mg/dl. The concentration of low-density lipoprotein cholesterol (LDL-C) positively correlated and that of high-density lipoprotein cholesterol (HDL-C) inversely correlated with the risk of CHD. Each 10 mg/dl decrease in LDL-C and each 10 mg/dl increase in HDL-C concentration reduced the risk of CHD by 8.0% (95% confidence interval 3.8-12.0) and 28.3% (95% CI 13.9-40.3), respectively. A reasonable therapeutic strategy to reduce CHD progression in patients with prior CHD under low-dose statin treatment might be regulating the serum LDL-C concentration to at least <120 mg/dl and HDL-C >40 mg/dl, respectively.

Adult↗
PubMed2002

[Complete remission of minimal change nephrotic syndrome with type 2 diabetes mellitus treated by microemulsion formulation of cyclosporin and fluvastatin].

A microemulsion formulation of cyclosporin (Neoral) has been developed to overcome the problems of poor and variable absorption of cyclosporin. Neoral is a potent immunosuppressive agent that is highly bound in the plasma. It has been proposed that low-density lipoprotein (LDL) delivers cyclosporin (CsA) to T-lymphocytes via the LDL receptor pathway, where it produces its therapeutic effects. Herein, we report a case of minimal change nephrotic syndrome with type 2 diabetes mellitus treated by Neoral and fluvastatin. A 65-year-old male with a 10-year history of type 2 diabetes mellitus suddenly developed nephrotic syndrome. The potential causative drugs, such as NSAIDs and antibiotics, had not been administered. The laboratory findings were as follows: proteinuria 23 g/day, serum albumin 1.9 g/dl, total cholesterol 629 mg/dl, LDL-Cho 1,930 mg/dl. Renal biopsy was normal on light microscopy, and immunofluorescence demonstrated no staining. Due to the risk of deterioration of diabetes by administering prednisolone, he was given Neoral at 2.0 mg/kg/day. He was also given fluvastatin (40 mg/day) for hyperlipidemia after the renal biopsy. At four weeks after the start of Neoral and fluvastatin, his nephrosis continued, but his LDL-Cho and total cholesterol decreased. At six weeks after treatment, proteinuria gradually reduced. At eight weeks after treatment, the proteinuria had disappeared. Nephrotic syndrome is often associated with abnormal lipid metabolism, and many patients with nephrotic syndrome show high levels of LDL-Cho. It has been reported recently that LDL apheresis is effective against nephrotic syndrome. However, in the present case, it can be speculated that the improvement of hyperlipidemia by fluvastatin probably augmented the effect of Neoral, presumably through the increased cellular uptake of Neoral. This suggests that fluvastatin may be considered as the treatment of choice for the disturbed lipoprotein profile in patients with nephrotic syndrome.

Anticholesteremic Agents↗
PubMed2002

[Hyperlipidemia and atherosclerosis].

One of the critical events in the early stage of atherosclerosis is the focal accumulation of lipid-laden foam cells derived from macrophages. In various cholesterol-fed animal models of atherosclerosis, it was found that localized attachment of circulating monocytes to arterial endothelial cells appears to precede the formation of foam cells. It has been suggested that monocyte recruitment into early lesions is depend upon the endothelial adhesiveness for monocytes and lymphocytes. In vivo and in vitro experiments have identified molecules, such as ICAM-1, VCAM-1 and P-selecin, those can support the adhesion of monocytes and lymphocytes. Moreover oxidized LDL, lysophosphatidylcholine and oxidized fatty acids induce the expression of not only these adhesion molecules but also scavenger receptors, such as CD-36, SR-A and LOX-1. Recently we isolated and characterized the novel receptors for oxidized LDL, named LOX-1 and SR-PSOX. The expression of LOX-1 is found on endothelial cells, smooth muscle cells and macrophages. Whereas SR-PSOX expresses on macrophages. We address in this paper on the significance of hyperlipidemia, especially oxidized LDL and its receptors in terms of atherosclerosis.

Animals↗
PubMedDate not supplied

Depression in Japanese community-dwelling elderly--prevalence and association with ADL and QOL.

This cross-sectional study examined the prevalence of screening-based depression and compared the scores of activities of daily living (ADL) and quality of life (QOL) between community-dwelling elderly subjects with and without depression in Japan. Elderly subjects aged 65 or older living in four rural towns participated in 2000 or 2001 (n = 5363, female 58.3%, mean (S.D.) age 74.6 (7.0) years). Depressive symptoms were assessed using a 15-item Geriatric Depression Scale (GDS-15) and ADL, higher functions, and medical and social histories were assessed by self-report questionnaires. For assessing subjective QOL, a 100 mm visual analogue scale was used. One thousand seven hundred ninety-eight participants (33.5%, range, 32.3-34.6%) had suggestive depression using cutoff 5/6 of GDS-15. Subjects with depression revealed significantly lower scores for ADL and QOL than those without depression. Prevalence of screening-based depression was similar in the four different rural Japanese towns. However, the reported prevalence of depression varies enormously in different country. Primary physicians and caregivers should pay more attention to depression in the community-dwelling elderly population, especially below the threshold of major depression as minor depression or dysthymia.

Activities of Daily Living↗