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Kent Doi

Publications and source records attributed to Kent Doi.

11 recordsLinked to original sources
PubMed2006

Efficacy of darbepoetin in doxorubicin-induced cardiorenal injury in rats.

This study was intended to elucidate the efficacy of an erythropoietin analog in cardiorenal dysfunction syndrome using a rodent model. Cardiorenal dysfunction was induced using doxorubicin hydrochloride (DXR). Lower doses (3 microg/kg) and higher doses (30 microg/kg) of darbepoetin alfa (DA) were used for intervention. Blood examinations for creatinine, blood urea nitrogen, iron, and hemoglobin were performed until 11 weeks after starting DA administration. Urine collection was performed 10 weeks after starting DA, and protein, iron, and N-acetyl-beta-D-glucosaminidase levels and antioxidation capacity of DA were determined. The dry left ventricular heart weight was measured, when the animals were sacrificed 11 weeks after starting DA administration. Histological analyses were performed for interstitial fibrotic changes and iron deposition in the kidney. Administration of DA markedly improved anemia to the normal control level and significantly alleviated DXR-induced increases of creatinine, blood urea nitrogen, renal interstitial fibrosis, renal iron deposition, and dry left ventricular weight, but serum and urinary iron and urinary protein and N-acetyl-beta-D-glucosaminidase levels were unchanged. The urinary total radical-trapping antioxidant capacity was improved to the normal control level in DA-treated animals. DA reduced the DXR-induced cardiorenal injury. This improvement was achieved, when anemia was corrected to the normal control level.

Acetylglucosaminidase↗
PubMed2006

Functional polymorphisms in the vascular endothelial growth factor gene are associated with development of end-stage renal disease in males.

This study elucidates the genetic role of vascular endothelial growth factor (VEGF) as a predisposing factor for progression of chronic kidney disease. Single-nucleotide polymorphisms were genotyped and haplotype structures were determined in the 3' untranslated region (UTR) of VEGF gene, and the distribution of each haplotype in male patients with ESRD (n=101) and healthy male control subjects (n=189) was examined. The 936C/T and 1451C/T polymorphisms in the 3' UTR were in nearly absolute linkage disequilibrium, and haplotype analysis demonstrated that they were the primary responsible single-nucleotide polymorphisms. The distribution of the 936CC-1451CC genotype was significantly more frequent among patients with ESRD than among the age-matched healthy control subjects. In addition to case-control association study, the 936CC-1451CC genotype was also associated with significantly higher plasma VEGF levels in healthy individuals, but a significant association was found only in males, not in females. We also examined the effect of the 936C-1451C haplotype on mRNA stability. Consistent with the results of plasma VEGF levels, mRNA carrying 936C-1451C haplotype showed higher stability. The 936CC-1451CC genotype in the 3' UTR showed not only susceptibility for ESRD but also higher plasma VEGF levels and mRNA stability, indicating the contribution of VEGF to chronic kidney disease progression, especially in males.

Adult↗
PubMed2006

Attenuation of folic acid-induced renal inflammatory injury in platelet-activating factor receptor-deficient mice.

Platelet-activating factor (PAF), a potent lipid mediator with various biological activities, plays an important role in inflammation by recruiting leukocytes. In this study we used platelet-activating factor receptor (PAFR)-deficient mice to elucidate the role of PAF in inflammatory renal injury induced by folic acid administration. PAFR-deficient mice showed significant amelioration of renal dysfunction and pathological findings such as acute tubular damage with neutrophil infiltration, lipid peroxidation observed with antibody to 4-hydroxy-2-hexenal (day 2), and interstitial fibrosis with macrophage infiltration associated with expression of monocyte chemoattractant protein-1 and tumor necrosis factor-alpha in the kidney (day 14). Acute tubular damage was attenuated by neutrophil depletion using a monoclonal antibody (RB6-8C5), demonstrating the contribution of neutrophils to acute phase injury. Macrophage infiltration was also decreased when treatment with a PAF antagonist (WEB2086) was started after acute phase. In vitro chemotaxis assay using a Boyden chamber demonstrated that PAF exhibits a strong chemotactic activity for macrophages. These results indicate that PAF is involved in pathogenesis of folic acid-induced renal injury by activating neutrophils in acute phase and macrophages in chronic interstitial fibrosis. Inhibiting the PAF pathway might be therapeutic to kidney injury from inflammatory cells.

Animals↗
PubMed2005

Haplotype analysis of NAD(P)H oxidase p22 phox polymorphisms in end-stage renal disease.

NAD(P)H oxidase is one of the most important sources of reactive oxygen species and has been demonstrated to be upregulated by angiotensin II in the kidney. Given the effect of angiotensin-converting enzyme inhibitors on the progression of both diabetic and non-diabetic renal disease, we hypothesized that the polymorphisms of NAD(P)H oxidase are associated with development of end-stage renal disease (ESRD). We examined five polymorphisms in the CYBA gene encoding the p22 phox component of NAD(P)H oxidase, including 242C/T and 640A/G polymorphisms in 467 ESRD patients and 490 healthy individuals. The T allele of the 242C/T polymorphism showed a protective effect against ESRD only in the nondiabetic (non-DM) group (P = 0.0095), and haplotype estimation revealed that the frequency of 242C-640A was higher in the non-DM group (46.7%) than in the control group (39.7%). The CC-AA genotype was still significantly associated with ESRD without diabetes after adjusting for confounding factors (P = 0.035). In contrast, there was no difference between the DM group and the control group. In conclusion, we identified a risk haplotype for nondiabetic ESRD in the CYBA gene using haplotype analysis. Haplotype analysis proved useful for elucidating the genetic contribution of NAD(P)H oxidase p22 phox to ESRD.

Adult↗
PubMed2005

Pulse total-hemoglobinometer provides accurate noninvasive monitoring.

OBJECTIVE: Rapid noninvasive measurement of total hemoglobin would be extremely useful for various clinical situations. This study determined the clinical accuracy and utility for a pulse total-hemoglobinometer using four wavelengths: 660 nm (reduced hemoglobin), 805 nm (isosbestic point), 940 nm (oxygenated hemoglobin), and 1300 nm (water density). DESIGN: Clinical trial. SETTING: University school of medicine. PATIENTS: Patients were 122 individuals (age, 18-82 yrs; 49.4 +/- 16.0 yrs [mean +/- SD]), including 71 healthy volunteers, 24 patients undergoing surgery, and 27 patients undergoing hemodialysis. INTERVENTIONS: The hemoglobinometer probe, which simultaneously indicated peripheral oxygen saturation, pulse rate, and hemoglobin, was placed on the fingertip similarly to a regular pulse oximeter. The hemoglobin values were compared with those obtained by the co-oximeter or the sodium lauryl sulfate-methemoglobin method. Those hemoglobin values were assigned to either the training set or the validation set for statistical evaluation. MEASUREMENTS AND MAIN RESULTS: Multiple regression analysis including the ratio of the pulsatile optical density (phi(ij)) derived from the four wavelengths and other factors demonstrated that the mean value of the normalized pulse wave obtained from the photodiode at 805 nm (DC805) and the ratios of DC940 and DC1300 (DC940/DC1300) were the pivotal factors in the hemoglobinometer's increased accuracy in the clinically useful range. The coefficient of determination between both methods was r2 = .81 (p < .0001) in the training set and r2 = .75 (p < .0001) in the validation set. When the cutoff value of anemia was set at 10 g/dL, and anemia was defined as <10 g/dL, the respective sensitivity and specificity of hemoglobinometer values to detect anemia in intraoperative patients were 84.3% and 84.6% (n = 20). CONCLUSIONS: The data demonstrated the necessity for consideration of light scattering in red blood cells for pulse-spectrophotometric hemoglobin measurement. This was accomplished with additional factors, such as DC805 and DC940/DC1300. With these improvements, the pulse hemoglobinometer provided noninvasive, clinically acceptable measurement of hemoglobin. The pulse hemoglobinometer is a versatile tool that might be useful for routine health checkups of neonates and young children, intraoperative monitoring of bleeding, and emergency care.

Adult↗
PubMed2004

High-throughput single nucleotide polymorphism typing by fluorescent single-strand conformation polymorphism analysis with capillary electrophoresis.

In this study, we performed high-throughput and precise single nucleotide polymorphism (SNP) typing by fluorescent capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) analysis. A system composed of a multicapillary DNA analyzer, a newly developed sieving matrix, four different colors of fluorescent labels, and a multiplex polymerase chain reaction (PCR) enabled low-cost and highly reliable SNP typing. Moreover, this system enabled the estimation of SNP allele frequencies using pooled DNA samples, which should be beneficial for large-scale association studies. Thus, fluorescent CE-SSCP analysis is a useful method for large-scale SNP typing.

DNA Fingerprinting↗
PubMed2004

Radical scavenger edaravone developed for clinical use ameliorates ischemia/reperfusion injury in rat kidney.

BACKGROUND: Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a potent scavenger of free radicals and has the antioxidant ability to inhibit lipid peroxidation. Its protective effect on brain ischemia has been shown. This study aimed to elucidate its possible therapeutic effects on renal oxidative stress in a rat ischemia/reperfusion model. METHODS: Ischemic acute renal failure was induced by 45-minute clamp of the left renal artery followed by administration of edaravone. Renal function and pathologic findings were examined. The generation of free radicals was observed by the fluorogenic probe, dichlorodihydrofluorescein (CM-H(2)DCFDA), and lipid peroxidation was observed by immunochemical staining and Western analysis of 4-hydroxy-2-hexenal (HHE). The ability of edaravone to reduce in vitro oxidative stress was investigated using cultured human renal tubular cells (HKC-8) and the cell viability assay with Alamar blue. RESULTS: Edaravone attenuated renal function and pathologic findings significantly. The protective effect of edaravone showed the dose-response was at the same level as that of dimethylthiourea. In addition, edaravone significantly reduced the generation of free radicals in the tubular cells indicated by CM-H(2)DCFDA. Immunochemical staining and Western analysis of HHE showed significant suppression of lipid peroxidation in edaravone-treated kidney. In HKC-8 cells loaded with CM-H(2)DCFDA, a marked elevation of fluorescence was observed after exposure to hydrogen peroxide (0.5 mmol/L, for 1 hour), which was reduced by edaravone. The cell viability assay with Alamar blue also showed the protective effect of edaravone. CONCLUSION: Edaravone ameliorates renal ischemia/reperfusion injury by scavenging free radicals produced in renal tubular cells and inhibiting lipid peroxidation.

Animals↗
PubMed2002

Successfully treated "accelerated" renovascular hypertension with intravascular stenting.

A 76-year-old man developed progressive renal dysfunction with refractory hypertension. Bilateral renal artery stenosis due to atherosclerosis was revealed. Both the hypertension and renal dysfunction were improved by percutaneous transluminal renal angioplasty with stenting. Based on the rapidly progressive elevation of plasma renin activity and the improvement of both renal dysfunction and hypertension after stenting, this was considered a case of "accelerated" renovascular hypertension. There have been an increasing number of patients with bilateral renal artery stenosis due to atherosclerosis. The present case reminds us that a rapid progression of renal dysfunction suggests, in addition to besides rapidly progressive glomerulonephritis with crescent formation, bilateral renal artery stenosis, the incidence of which is on the rise. In the present case, angioplasty with stenting was effective for blood pressure control and preservation of renal function.

Aged↗