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Biomedical subjects

Kenji Hamaoka

Publications and source records attributed to Kenji Hamaoka.

At least 19 recordsLinked to original sources
PubMed2007

A randomized prospective study on the use of 2 g-IVIG or 1 g-IVIG as therapy for Kawasaki disease.

A single, 2 g/kg dose of immune globulin (IG), denoted 2 g-intravenous (IV)IG, has become a standard regimen for treating Kawasaki disease (KD) because of its highly preventive effect on coronary arterial lesions (CAL). However, IG is obtained from blood specimens, a drawback to many patients, and is also very expensive. This randomized prospective study reported here was carried out with the aim of developing a treatment regimen that would reduce the total dose of IG. The study tested two protocols (A: 2 g-IVIG; B: 1 g-IVIG) that included the strategy of administering additional IVIG to IVIG-resistant patients based on the criteria we described previously. In protocol A, an additional 2 g-IVIG was administered only once; in protocol B, the first additional IVIG was 1 g-IVIG and the second was 2 g-IVIG. One hundred and nine patients who were admitted before the seventh day of illness and had no CAL at the time of admission were enrolled in the study (protocol A: 54 patients; B: 55 patients). In the protocol A group, 7.4% (4/54) of the patients received 4 g/kg IG. In protocol B, 41.8% (23/55) were treated only with 1 g/kg IG, and 10.9% (6/55) received 4 g/kg IG. No significant differences were observed between the patients of the two subgroups receiving 4 g/kg IG in each protocol group. Discriminate analysis also suggested that 52.4% of the patients in the protocol A group could be treated only with 1 g/kg IG. On the other hand, no significant difference was observed in the incidence of aneurysms between patients in the protocol A group (1/54) and those in the protocol B group (4/55). Our protocol based on 1 g-IVIG, including additional IVIG, was assessed to be an effective treatment and to provide a considerably useful means to reduce the total dose of IG.

Child↗
PubMed2006

MMP-2 inhibition reduces renal macrophage infiltration with increased fibrosis in UUO.

We examined the role of matrix metalloproteinase-2 (MMP-2) in renal fibrosis and its effect on interstitial macrophage infiltration in a mouse model of unilateral ureteral obstruction (UUO). TISAM, a selective inhibitor of MMP-2, was administered during early stage (day -2 to 4; protocol A) and late stage (day 7 to 13; protocol B) after UUO. Treatment with TISAM accelerated fibrosis both at day 5 (A) and at day 14 (B). The degree of macrophage infiltration was decreased by the treatment with TISAM at day 14, but not at day 5. In vitro macrophage migration assay showed a greater migration to renal tissue of control UUO kidney (day 14) than to TISAM-treated kidney, which was suppressed by preincubating macrophages with RGDS, a fibronectin degradation peptide. These results suggest that MMP-2 acts to accelerate macrophage infiltration in the late stage of UUO, possibly by degrading extracellular matrix components.

Animals↗
PubMed2006

How does G-CSF act on the kidney during acute tubular injury?

Recent findings in stem cell research have demonstrated multi-lineage plasticity of bone marrow cells, and also the contribution of hematopoietic bone marrow stem cells to the regeneration of injured organs including the kidney. These findings suggested the possibility of the use of granulocyte colony-stimulating factor (G-CSF) as a therapeutic option to regenerate injured organs. Recently, several studies regarding the effect of G-CSF on renal function have been reported in mouse models of acute renal failure. This series of experiments provided potentially important information regarding the treatment of patients with renal injury. This review summarizes the possible actions of G-CSF on the kidney, especially during acute tubular injury caused by toxic or ischemic insults.

Acute Kidney Injury↗
PubMed2006

Characteristics of brachial-ankle pulse wave velocity in Japanese children.

BACKGROUND: Measurement of pulse wave velocity (PWV) is a useful approach for evaluating the severity of atherosclerosis in adults, and, in particular, the measurement of brachial-ankle PWV (baPWV) has been commonly reported as a simple and practicable method. We attempted to investigate how baPWV in healthy children changes with age and gender, in order to assess baPWV in children with risk factors for the early progression of systemic atherosclerosis. METHODS: We measured baPWV in 970 healthy Japanese children (500 boys and 470 girls), and set up the normal baPWV values of children on the basis of age and gender. We also performed linear regression analysis and step-wise multiple regression analysis for evaluating its correlation with baPWV and independent variables for baPWV in children. RESULTS: The values of baPWV in children were higher in boys than in girls, and baPWV increased with age in both genders. Age, blood pressure and heart rate (HR) were significant determinants of baPWV in both male and female subjects, while the obesity index had no correlation with baPWV. CONCLUSION: On the basis of these results, we suggest that baPWV in children is largely influenced by age and gender, and that baPWV gradually increased with age in both genders.

Adolescent↗
PubMed2006

Renal function and cardiac angiography.

OBJECTIVE: To study the effect of non-ionic contrast medium on renal function in children with cardiovascular disease. METHODS: Analysis of renal function in 98 children with cardiovascular disease before and after the use of Iopamidol, Iohexol, and Ioversol was done for angiography. Serum creatinine (s-Cre), urinary N-acetyl-beta-D-glucosaminase (u-NAG), urinary beta 2-microglobulin (u-BMG), and urinary alpha 1-microglobulin (u-AMG) levels were evaluated. RESULTS: Although s-Cre levels remained unchanged, u-NAG/Cre, u-AMG/Cre and u-BMG/Cre significantly increased 12 hours after angiography. Levels of u-NAG/Cre, u-BMG/Cre, and u-AMG/Cre after angiography were significantly higher in neonates and infants (age< 12-months, n=32) than in children (age>1-year, n=61), in patients with more than 5 ml/kg of contrast medium (n=25) than in those with less than 5 ml/kg (n=70) and in cyanotic patients (n=13) than in non-cyanotic (n=80) patients. CONCLUSION: Transient renal tubular dysfunction occurred in all of these three non-ionic contrast mediums. Although renal tubular function was intact on a long-term basis, one should be careful of contrast medium-induced nephropathy, especially in neonates and infants, in patients receiving more than 5 ml/kg of contrast mediums in total, and in patients with cyanotic heart disease in using non-ionic contrast mediums.

Adolescent↗
PubMed2005

C1q nephropathy with asymptomatic urine abnormalities.

We found four cases of C1q nephropathy (C1qN) among a total of 193 pediatric series of first renal biopsies. Among them, 94 biopsies were performed because of asymptomatic urine abnormalities detected by school urinary screening program in Japan; three cases out of these 94 biopsies (3.2%) met the criteria of C1qN. One case out of the remaining 99 biopsies with symptomatic renal diseases (1%) also met the criteria of C1qN. Three cases with asymptomatic onset presenting with mild proteinuria with or without hematuria equally showed histologic features of membranoproliferative glomerulonephritis and showed improvements in urinalysis without corticosteroid treatment. Our data suggest that membranoproliferative glomerulonephritis may be a common histological feature of asymptomatic pediatric C1qN in Japan and that this type of glomerulopathy may follow a relatively good clinical course without steroid therapy.

Adolescent↗
PubMed2005

Adoptive transfer of macrophages ameliorates renal fibrosis in mice.

We performed adoptive transfer of bone marrow-derived (BM) macrophages following pharmacological depletion of leukocytes in a mouse model of unilateral ureteral obstruction (UUO). Treatment with cyclophosphamide (CPM) caused marked decrease in the numbers of F4/80-positive interstitial macrophages as well as in peripheral blood leukocyte counts, and adoptive transfer of BM macrophages to CPM-treated mice resulted in significant increase in the numbers of interstitial macrophages both at day 5 and at day 14 after UUO. At day 5 after UUO, no significant change was observed in the degree of renal interstitial fibrosis either by treatment with CPM or with CPM+macrophage. However, at day 14 after UUO, treatment with CPM caused significant increase in the degree of interstitial fibrosis, and adoptive macrophage transfer to these mice attenuated this enhancement in renal fibrosis. Our result suggests the role of infiltrating macrophages on facilitating tissue repair at late stage of UUO.

Adoptive Transfer↗
PubMed2005

Long-term changes in coronary artery aneurysms in patients with Kawasaki disease: comparison of therapeutic regimens.

BACKGROUND: There are few studies of the therapeutic regimens for the prevention of stenotic transformation of aneurysms in Kawasaki disease (KD). The aim of this study was to assess the prophylactic effect of combined therapy in the acute stage and convalescent- to chronic-stage against the formation of stenotic lesions. METHODS AND RESULTS: In 85 patients, 103 giant aneurysms (ANl), 46 medium-sized aneurysms (ANm), and 13 small aneurysms (ANs) were analyzed. With respect to therapy in the acute stage, no localized stenosis of ANl in the left coronary artery was noted in patients who received high-dose gamma globulin therapy (G). For ANm, the group (G) showed a significantly higher regression rate than the aspirin group and steroids group. Furthermore, no coronary artery occlusion/recanalization of ANl occurred with the prophylactic regimen of aspirin and warfarin {aw}. Prophylaxis {aw} and the prophylactic regimen of aspirin alone {a} significantly lowered the incidence compared with either the prophylactic regimen of warfarin {w} or no prophylaxis {n}. However, no significant differences were noted between prophylaxis {w} and {n}. CONCLUSIONS: High-dose gamma globulin therapy in the acute stage of KD is the first choice for the prevention of stenotic transformation. Prophylaxis {aw} is recommended for ANl.

Acute Disease↗
PubMed2005

Rapidly progressive IgA nephropathy.

A 14-year-old boy presented with macroscopic hematuria and a rapid deterioration in renal function. Percutaneous renal biopsy demonstrated severe crescentic IgA nephropathy (IgAN) with extensive (88%) glomerular crescent formation. After started intravenous administration of high-dose pulse methylprednisolone, severe nausea and general malaise accompanied by a rapid increase in Blood Urea Nitrogen (BUN) and serum creatinine levels appeared, however, the renal function ameliorated rapidly and fully recovered by following oral administration of corticosteroid. The clinical presentation of our case seems to be very remarkable compared to previously reported cases of rapidly progressive IgAN.

Adolescent↗
PubMed2004

Effect of hematopoietic cytokines on renal function in cisplatin-induced ARF in mice.

In this study, the effect of hematopoietic cytokines, i.e., granulocyte-colony stimulating factor (G-CSF), stem cell factor (SCF), and granulocyte-macrophage-colony stimulating factor (GM-CSF), on renal function was studied in cisplatin-induced acute renal failure in mice. Treatment with G-CSF significantly ameliorated both BUN and serum creatinine increase induced by cisplatin administration with concomitant alleviation in the degree of necrotic change, enhancement in DNA synthesis, and decrease in apoptosis of renal tubular cells. There was no significant change observed among these parameters following treatment with SCF or with GM-CSF. Serum hepatocyte growth factor level was significantly lower in mice treated with cisplatin and G-CSF compared with that in those treated with cisplatin only. In conclusion, G-CSF, but not SCF or GM-CSF, acts to accelerate regeneration and prevent apoptosis of renal tubular epithelial cells and leads to reduced renal injury in cisplatin-induced acute renal failure in mice.

Acute Kidney Injury↗
PubMed2004

Possible synergic effect of angiotensin-I converting enzyme gene insertion/deletion polymorphism and angiotensin-II type-1 receptor 1166A/C gene polymorphism on ischemic heart disease in patients with Kawasaki disease.

ACE I/D and AT1R 1166A/C polymorphisms are considered to comprise individual risk factors for the development of coronary disease. We sought to demonstrate that the ACE I/D and AT1R 1166A/C polymorphisms affect coronary artery stenosis in patients with Kawasaki disease (KD). We examined 147 healthy controls and 281 Japanese children with KD. The patients were further divided into group N (n = 246, no ischemia) and group I (n = 35, severe coronary artery stenosis with myocardial ischemia), and we studied the genotype of ACE I/D and AT1R 1166A/C polymorphisms. We also examined ACE activity in patients with acute KD. We did not detect any prevalent genotypes of the ACE and AT1R polymorphisms between controls and KD patients. However, the prevalence of the D allele in the ACE polymorphism and of the C allele in the AT1R polymorphism tended to be higher in group I than in group N (odds ratios, 2.00 and 2.32, respectively). In addition, the presence of the D and/or C alleles significantly increased the relative risk of developing myocardial ischemia (odds ratio, 2.71; p = 0.038). During the convalescent phase of KD, ACE activity was increased despite significant attenuation during the acute phase. These results suggested that the renin-angiotensin system is associated with the formation of severe coronary artery stenosis and myocardial ischemia.

Acute Disease↗
PubMed2004

Coronary artery obstruction due to membranous ridge of the right sinus valsalva associated with Tetralogy of Fallot: syncope mimics anoxic spell.

We report an infant with Tetralogy of Fallot who had suffered from repetitive attacks of syncope without obvious cyanosis. Careful observation by means of echocardiography and angiography revealed that the attacks resulted from acute coronary artery obstruction due to membranous ridge covering the sinus Valsalva. Surgical resection of the abnormal ridge and repair of Tetralogy of Fallot successfully improved the patient's symptoms. Syncope in children should be extensively investigated to exclude obstruction of the coronary arteries.

Abnormalities, Multiple↗