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Biomedical subjects

K Dohi

Publications and source records attributed to K Dohi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Effects of JTV-519, a novel anti-ischaemic drug, on the delayed rectifier K+ current in guinea-pig ventricular myocytes.

We studied the effects of a newly synthesized anti-ischaemic agent, 4-[3-(4-benzylpiperidin-1-yl) propionyl]-7-methoxy-2, 3, 4, 5-tetrahydro-1, 4-benzothiazepine monohydrochloride (JTV-519) on the delayed rectifier potassium current (IK), using guinea-pig ventricular myocytes and whole-cell voltage-clamp techniques, under blockade of the L-type calcium current (ICa,L) by D600 (1 microM) or nitrendipine (5 microM). The IK in guinea-pig ventricular cells consists of two different components; the rapidly activating, E4031-sensitive component (IKr) and the slowly activating E4031-resistant component (IKs). Under steady-state conditions, JTV-519 (1 and 5 microM) did not change the amplitude of IKs remaining after blockade of IKr with 5 microM E4031. The effect of JTV-519 on IKr was assessed using short (50 ms) pulses which evoked a tail current that was sensitive to E4031 but not to chromanol 293B, a specific blocker of IKs. JTV-519 suppressed the IKr with a half-maximal inhibitory concentration of 1.2 microM. Selective inhibition of IKr by this agent was confirmed by using the "envelope of tails" test. These results suggest that the blockade of IKr may underlie the prolongation of action potential duration in ventricular muscle and QT-intervals alleged to occur in animal as well as human hearts.

Action Potentials↗
PubMed2000

Association of Chlamydia pneumoniae infection with diabetic nephropathy.

We evaluated the association of Chlamydia pneumoniae (CP) infection with progression of diabetic nephropathy. Type 2 diabetic patients (60) were divided into two groups, those with incipient nephropathy and those with advanced nephropathy, based on the severity of diffuse glomerular lesions using Gellman's criteria. Type 2 (34) diabetic patients without nephropathy (normoalbuminuria) and 59 nondiabetics served as control groups. Serum IgG-antibody against CP was measured using ELISA. CP antibody was detected in 45.8% of nondiabetic controls, in 47.1% of diabetic patients without nephropathy, in 52.6% of diabetic patients with incipient nephropathy, and 78% of diabetic patients with advanced nephropathy. There was 4.22-fold increase in the risk of advanced nephropathy associated with the presence of CP antibody. Our findings indicate an association between chronic CP infection and advanced diabetic nephropathy.

Aged↗
PubMed2000

Serum IgA levels in patients with diabetic nephropathy and IgA nephropathy superimposed on diabetes mellitus.

The aim of this study was to examine the relationship between serum immunoglobulin A (IgA) levels and diabetic nephropathy in patients with type 2 diabetes mellitus, and to describe the role of IgA nephropathy superimposed on diabetes mellitus. A total of 127 type 2 diabetic patients were studied. Of these diabetics, 74 had no proteinuria, 35 had diabetic glomerulosclerosis confirmed by renal biopsy, 13 had superimposed IgA nephropathy, and five had superimposed non-IgA nephropathy. We also studied 93 non-diabetic patients with IgA nephropathy, 24 non-diabetic patients with non-IgA nephropathy, and 38 non-diabetic controls. Serum IgA levels were significantly higher in IgA nephropathy patients (350+/-130 mg/dl) than in non-diabetic controls (228+/-56 mg/dl) and diabetics without proteinuria (268+/-104 mg/dl). Serum IgA levels were also significantly higher in diabetics with superimposed IgA nephropathy (470+/-208 mg/dl) than in non-diabetic controls, non-IgA nephropathy patients (270+/-133 mg/dl), diabetics without proteinuria, diabetic glomerulosclerosis alone (302+/-126 mg/dl), and diabetics with superimposed non-IgA nephropathy (248+/-137 mg/dl). The prevalence of high serum IgA levels was significantly higher in diabetics with superimposed IgA nephropathy (76.9%) than in diabetic glomerulosclerosis alone (31.4%) and diabetics with superimposed non-IgA nephropathy (25.0%). In conclusion, our findings indicate that high serum IgA level is a sign of the existence of IgA nephropathy superimposed on diabetes mellitus.

Adult↗
PubMed2000

Reduced early diastolic inflow velocities in the antero-posterior transverse direction in the left ventricle of patients with dilated cardiomyopathy.

UNLABELLED: In patients with dilated cardiomyopathy (DCM), the left ventricular (LV) inflow jet is narrow and has a high pressure gradient. A pulsed Doppler restrictive transmitral flow pattern is a characteristic feature of severe left ventricular disease. However, Doppler flow analysis is limited by the angle between the blood flow jet and the ultrasonic beam. In this study we used gated magnetic resonance imaging (MRI) to investigate the inflow velocity in the LV transverse directions during early diastole in patients with DCM. METHODS: We studied 10 patients with DCM (mean age: 47 y). Ten age-matched healthy volunteers were also examined. Gradient echo images of the LV were obtained. Left ventricular short axis phase contrast images were obtained at the level of the mitral valve tip and 1 cm inside the LV. Long axis images were also obtained. Through-plane peak velocities at peak early diastolic filling were measured along the LV long axis, antero-posterior short axis, and right-left short axis. Blood velocity was measured in 50 ms blocks. RESULTS: Early diastolic inflow velocity along the long axis, especially at the center of the LV, was well preserved in DCM. However, the inflow velocity in the antero-posterior transverse direction of the LV (i.e., in the direction of mitral valve excursion) was significantly reduced in DCM. CONCLUSIONS: Early diastolic inflow velocity in the antero-posterior transverse direction of the LV is reduced in patients with DCM indicating that the vector component of the forces acting in the antero-posterior transverse direction of the LV may be decreased in patients with DCM during early diastolic filling.

Adult↗
PubMed2000

Effect of the 21-aminosteroid on nuclear factor-kappa B activation of Kupffer cells in endotoxin shock.

BACKGROUND: The 21-aminosteroid (U-74389G) is a nonglucocorticoid steroid that was synthesized to inhibit lipid peroxidation without the glucocorticoid activity. We recently demonstrated that the 21-aminosteroid administered to endotoxin shock mice reduces liver injury and improves the survival rate of mice through inhibition of nuclear factor-kappa B activation in the liver. The study was undertaken to determine whether the 21-aminosteroid could suppress pro-inflammatory gene up-regulation through inhibition of nuclear factor-kappa B activation in Kupffer cells. METHODS: Kupffer cells were isolated from rats by collagenase perfusion followed by pronase digestion. After a lipopolysaccharide addition, each assay was performed for tumor necrosis factor-alpha, interleukin-6, tumor necrosis factor-alpha messenger RNA, nuclear factor-kappa B, and I kappa B proteins. RESULTS: After the lipopolysaccharide addition, Kupffer cells released both tumor necrosis factor-alpha and interleukin-6. The 21-aminosteroid treatment suppressed the release of tumor necrosis factor-alpha in a dose-dependent manner. The 21-aminosteroid also inhibited the increase of tumor necrosis factor-alpha messenger RNA expression and nuclear factor-kappa B activation in Kupffer cells 1 hour and 30 minutes, respectively, after lipopolysaccharide addition. Furthermore, the 21-aminosteroid treatment suppressed the degradation of I kappa B proteins in lipopolysaccharide-stimulated Kupffer cells. CONCLUSIONS: These results suggest that the 21-aminosteroid inhibits release of the tumor necrosis factor-alpha and interleukin-6 from lipopolysaccharide-stimulated Kupffer cells by inhibiting nuclear factor-kappa B activation. This is accomplished by inhibiting I kappa B degradation in endotoxin shock and this may prove useful for the treatment of endotoxin shock.

Animals↗
PubMed2000

The negative inotropic effect of beta3-adrenoceptor stimulation in the beating guinea pig heart.

Although beta3-adrenoceptors (ARs) have been extensively characterized in brown and white adipocytes, their actions in the beating heart are unclear. We examined the effects of a beta3-AR agonist, BRL37344, on cardiac function and calcium transients in Langendorff-perfused guinea pig hearts by simultaneously measuring left ventricular (LV) pressure and Ca2+-dependent indo-1 fluorescence. BRL37344 induced a dose-dependent negative inotropic effect at concentrations from 10(-11) to 10(-8) M. Maximally, LV developed pressure decreased to 80+/-2%, +dP/dt to 81+/-2%. and -dP/dt to 81+/-3% of their respective control values (p < 0.01). The amplitude of the Ca2+ transient also decreased (to 92+/-3% of the control level; p < 0.01). The BRL37344 dose-response curve was not altered by nadolol (10(-5) M), a potent beta1- and beta2-AR antagonist, but completely suppressed by bupranolol (10(-6) M), a potent beta1-, beta2- and beta3-AR antagonist. To assess the potential role of a nitric oxide synthase (NOS) pathway, we determined whether the NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), modified the contractile response to BRL37344. L-NAME (10(-7) and 10(-4) M) attenuated the negative inotropic effects on LV developed pressure by 35 and 50%, suggesting that beta3-AR stimulation induces a negative inotropic effect on guinea pig hearts partly through a decrease in the Ca2+ transient and partly by the NOS pathway.

Adrenergic beta-Agonists↗
PubMed2000

Effects of exercise and alkalosis on serum insulin-like growth factor I and IGF-binding protein-3.

This investigation examines the effects of orally induced alkalosis on serum IGF-I and IGFBP3 concentrations in response to an acute 90-s bout of high intensity cycle exercise. Ten healthy, active men, ages 24.60 +/- 4.90 years, participated in a randomized, double-blind, counterbalanced trial order with a cross-over design. Subjects ingested an experimental bicarbonate solution or a placebo solution. Blood was sampled at baseline; pre-exercise; and 0, 5, 10, and 30 min postexercise. The pH between groups for pre-exercise and postexercise time points differed significantly (p < or = .05) in the experimental condition (from 7.42 +/- 0.01 to 7.35 +/- 0.02) versus the placebo condition (from 7.36 +/- 0.01 to 7.25 +/- 0.03). Increases in IGF-I over resting conditions occurred with placebo conditions at 5 and 10 min postexercise and in the experimental condition at 5 min postexercise. Concentrations of IGFBP3 were elevated above baseline at IP in both experimental and placebo conditions.

Adolescent↗
PubMed2000

Adrenomedullin gene transcription is decreased in peripheral blood mononuclear cells of patients with IgA nephropathy.

We measured mRNA levels of adrenomedullin (AM), C-type natriuretic peptide (CNP), vascular endothelial growth factor (VEGF), interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) in peripheral blood mononuclear cells (PBMC) of patients with IgA nephropathy. To evaluate these mRNA levels, we employed a real-time quantitative PCR method which was performed using a hybridization probe labeled with two fluorescence dyes. This strategy was found to afford the standard curves with a high correlation, suggesting that this method is useful for evaluations of mRNA levels. By this method, levels of AM, CNP, VEGF, IL-1beta and IL-6 mRNA in PBMC of 49 IgA nephropathy patients and 35 healthy volunteers were evaluated. Among the mRNAs examined, AM mRNA levels were significantly lower in severe-grade than in mild-grade IgA nephropathy patients. Furthermore, AM mRNA levels correlated with CNP mRNA levels in PBMC of patients with IgA nephropathy, and each peptide generated from these mRNAs has antiproliferative effects on mesangial cells. These data indicate that gene expression of AM in PBMC is regulated according to the pathophysiological states of IgA nephropathy and that decreased AM production may contribute to the progression of IgA nephropathy.

Adrenomedullin↗
PubMed2000

Primary focal segmental glomerulosclerosis: clinical course, predictors of renal outcome and treatment.

Primary focal segmental glomerulosclerosis (FSGS) is the representative of refractory nephrotic syndrome in both adults and children. We review the clinical course and predictors of renal outcome in adult FSGS. Patients resistant to treatment frequently develop end-stage renal disease (ESRD), whereas patients achieving a remission show an excellent outcome. The renal survival rate in Japanese patients is 68.7% in 10 years and 31.4% in 20 years, indicating a better prognosis compared with the previous studies. When clinical and histological features at presentation have been evaluated by multivariate analysis, serum creatinine concentrations (>1.5 mg/dl) and the presence of tubulo-interstitial lesions (>20%) are significant positive predictors of progression to ESRD. We also discuss treatment for adult FSGS, with emphasis on intensive and prolonged therapy.

Adult↗
PubMed2000

Catastrophic antiphospholipid antibody syndrome in systemic lupus erythematosus: an autopsy case report of a young woman.

Catastrophic antiphospholipid syndrome (CAPS) is a severe variant of antiphospholipid syndrome (APS) characterized by disseminated microangiopathy that results in multiorgan failure. CAPS mainly occurs in association with systemic lupus erythematosus (SLE). Clinically, CAPS mimics disseminated SLE vasculitis, intravascular coagulation (DIC), and particularly thrombotic thrombocytopenic purpura (TTP). We describe an autopsy case of young woman with CAPS in SLE, which is difficult to differentiate from TTP secondary to SLE.

Adult↗