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Biomedical subjects

Yasuhiko Iwamoto

Publications and source records attributed to Yasuhiko Iwamoto.

At least 19 recordsLinked to original sources
PubMed2006

Renoprotective effects of tea catechin in streptozotocin- induced diabetic rats.

Tea catechins, a class of flavonoids, are suggested to have biological effects, possibly mediated through their antioxidative properties. Recent data indicated that tea catechins suppressed proliferative changes in glomeruli and inhibited the development of glomerulosclerosis in partially nephrectomized rats. We thus sought to determine whether tea catechins may protect against renal dysfunction in streptozotocin-induced diabetic rats. Four groups of male Sprague-Dawley rats (n=11-15 per group), with and without streptozotocin-induced diabetes, were treated with and without catechins (5 mg/day) administered in the drinking water for 12 weeks. At the end of the treatment period, 24-hour urinary albumin excretion rate (AER), serum lipid peroxides as thiobarbituric acid reactive substrates (TBARS) and blood pressure were measured. Renal glomerular volume and interstitial fibrosis were assessed morphologically. Albuminuria developed progressively in untreated diabetic rats, resulting in a mean AER of 559+/-124 (mean+/-SE) versus 63+/-7 microg/day/100 g body weight in non-diabetic rats at 12 weeks (P<0.001). Catechin treatment significantly reduced AER to 287+/-56 microg/day/100 g body weight in diabetic rats (P=0.017 versus untreated diabetic rats). Increased interstitial fibrosis in the kidney, observed in untreated diabetic rats, was completely normalized with catechin treatment. Serum levels of TBARS and blood pressure were comparable among the four groups. In conclusion, administration of tea catechin retards the progression of functional and morphological changes in the kidney of streptozotocin-induced diabetic rats.

Animals↗
PubMed2006

Survey of dietary habits in obese patients with type 2 diabetes treated with either OHA or insulin injections in Japan.

A questionnaire survey on meal/snack intake and timing in obese patients with type 2 diabetes treated with either oral hypoglycemic agents (OHA) or insulin injections was performed in order to elucidate their dietary habits, using a method independent of the treating physician. The OHA and insulin groups recruited from all over Japan showed no differences in any factors except the duration of diabetes. Daily calorie intake was not correlated with gender, BMI, medication or HbA1c. However, calorie intake was the highest at dinner, followed by lunch and breakfast. Only for dinner was the calorie intake significantly higher for the OHA group than for the insulin group. Of the patients, 8.6, 4.2 and 1.3% skipped breakfast, lunch or dinner, respectively. However, there was no significant difference in the abstention ratio for the three meals or between the two treatment groups. It was remarkable that at least 90% or more reported the habitual ingestion of snacks. The snack time ranged from 6:00 a.m. to midnight. There was no marked difference in the proportion of patients having snacks between the two treatment groups. The outcomes such as deviations in calorie intake among the three meals, skipping meals and snacking in this survey may reflect the current dietary habits of obese patients with type 2 diabetes, especially under medical treatment.

Adult↗
PubMed2006

Development of an ELISA for esRAGE and its application to type 1 diabetic patients.

We recently identified a naturally occurring soluble form of RAGE (the receptor for advanced glycation endproducts, receptor for AGE) in cultured human vascular cells, and named it endogenous secretory RAGE (esRAGE). esRAGE is generated by alternative RNA splicing and is able to capture AGE, and exerts protection against AGE-induced endothelial cell injury. In the present study, the presence of esRAGE in human circulation was demonstrated for the first time, and a highly sensitive and specific sandwich ELISA system for esRAGE was developed to see whether esRAGE could be related to an individual resistance to the development of diabetic vascular complications. Sera from 47 type 1 diabetic subjects without clinical nephropathy (urinary albumin excretion <300mg/g creatinine) and 55 healthy controls were analyzed by the ELISA. Circulating esRAGE concentrations in diabetic patients with simple and proliferative retinopathy (0.09+/-0.02ng/mL, n=16 and 0.08+/-0.02ng/mL, n=8, respectively) were significantly lower than in those without retinopathy (0.13+/-0.06ng/mL, n=23). The results indicate that esRAGE can be a useful biomarker to indicate individual variations in susceptibility to diabetic retinopathy.

Antibodies, Monoclonal↗
PubMed2006

Vardenafil 20-mg demonstrated superior efficacy to 10-mg in Japanese men with diabetes mellitus suffering from erectile dysfunction.

AIM: Vardenafil is a highly selective and potent phosphodiesterase type-5 inhibitor for the treatment of erectile dysfunction (ED). The efficacy of vardenafil has been demonstrated in a broad range of ED populations, but has not yet been assessed in Japanese patients with diabetes mellitus (DM), although DM is frequently associated with difficult-to-treat ED. This is the first study to investigate whether high-dose vardenafil (20 mg) can demonstrate superior efficacy to the usual dose (10 mg) in this subpopulation in Japan. METHODS: The study was a randomized, placebo-controlled, double-blind, multi-centre, parallel group comparison 12-week study. Following 4 weeks observation period, 778 patients aged 26-64 years old with ED and DM (HbA1c >12% at screening was excluded) both of more than 3 years duration were randomly allocated to one of the three groups, vardenafil 10 mg, 20 mg, or placebo (randomization ratio 3:3:1). Erectile function (EF) domain score of the International Index of Erectile Function was estimated as the primary efficacy parameter. RESULTS: Vardenafil 10 and 20 mg both significantly improved the EF domain score from 13.6 and 13.9 at baseline to 21.8 and 22.9 at last observation carried forward (LOCF), respectively, compared to placebo (13.7 at baseline to 16.3 at LOCF; p<0.0001). In addition, vardenafil 20 mg demonstrated superior efficacy to 10 mg (p<0.05), and the difference was more evident in severe ED patients (baseline EF domain score <11). The safety profile was comparable between these two doses (drug-related adverse events: 6.6, 22.0 and 24.2% in placebo, vardenafil 10 mg, and 20 mg arms, respectively). The most common adverse events were hot flush, headache and nasal congestion, which were mild in intensity and transient, and are known to be common to PDE5 inhibitors. CONCLUSION: In Japanese men with DM and ED, vardenafil 10 mg and 20 mg were effective in improving erectile function with comparable safety profiles. Vardenafil 20 mg demonstrated superior efficacy compared with 10 mg, suggesting incremental clinical benefit in using the higher dose in this difficult-to-treat population.

Adult↗
PubMed2006

Oxidative stress-responsive transcription factor ATF3 potentially mediates diabetic angiopathy.

Previous results of our cDNA microarray analysis to look for genes whose expression level correlates well with in vitro tubulogenesis by NP31 endothelial cells revealed the transcription factor ATF3 known to be responsive to stress such as reactive oxygen species (ROS). Anti-ATF3 small interfering RNA gave an inhibitory influence on tube formation by NP31 cells expressing an activated form of the vascular endothelial growth factor receptor 1 (VEGFR-1) kinase. When expression of ATF3 was regulated under the control of tetracycline system in NP31 cells, they acquired the tubulogenic ability upon ATF3 induction. While ATF3 failed to induce expressions of VEGF and VEGFR, it regulated those of CDK2, CDK4, p8, plasminogen activator inhibitor 1, integrin alpha1, subunit and matrix metalloprotease MMP13. In H2O2-stimulated NP31 cells as well as endothelial cells of glomerulus and aorta of Otsuka-Long-Evans-Tokushima-Fatty diabetic model rats, concomitantly enhanced expressions of ATF3, PAI-1, and p8 were observed. Given the proposed hypothesis of the close linkage between diabetic angiopathy and ROS, those data suggest that ROS-associated diabetic complication may involve ATF3-mediated pathological angiogenesis.

Activating Transcription Factor 3↗
PubMed2006

Pulse pressure and chronic kidney disease in patients with type 2 diabetes.

To determine the association between both age and degree of albuminuria and pulse pressure in patients with type 2 diabetes, we conducted this study consisting of two cross-sectional observations. A total of 833 ambulatory and 107 hospitalized type 2 diabetic patients with serum creatinine <2.00 mg/dl were studied. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) were compared among ambulatory patients stratified according to the degree of albuminuria, as well as according to age at 10-year intervals. In the hospitalized patients, 24-h blood pressure was monitored, and 24-h SBP, DBP, and PP were correlated with aortic pulse wave velocity (PWV) and mean intima-media thickness (IMT) of the carotid arteries. In the ambulatory patients, SBP and PP were greater in patients with microalbuminuria and clinical albuminuria, as well as in the older groups, whereas DBP tended to be lower in the older age groups. Multiple regression analysis adjusted for covariates including age indicated that increased albuminuria was independently associated with greater PP (p < 0.001). In the hospitalized patients, stepwise increases were observed in SBP and PP (daytime, nighttime and overall 24-h), but not in DBP, in microalbuminuric and albuminuric patients. SBP and PP were positively and DBP was negatively associated with aortic PWV; however, no association was found with IMT. In conclusion, PP is closely associated with higher age, degree of albuminuria, and large artery stiffness in patients with type 2 diabetes.

Adult↗
PubMed2006

[A case of gastric cancer with abdominal wall invasion treated by weekly low-dose paclitaxel therapy].

Here we report a case of gastric cancer with diffuse abdominal wall invasion treated with weekly low-dose paclitaxel therapy. A 62-year-old male visited our hospital because of abdominal distention, prepubic tumor,and testicular hydrocele. Computed tomography revealed diffuse swelling of the abdominal wall and hydronephrosis of the right kidney. Upper gastrointestinal endoscopy demonstrated type 3' advanced gastric cancer. Pathological diagnosis of both gastric tumor and abdominal wall biopsy specimens was poorly-differentiated adenocarcinoma containing signet ring cell carcinoma. Low-dose paclitaxel (90 mg/body) was given once a week for 3 weeks. Abdominal wall swelling like cuirass disappeared after 2 courses of low-dose paclitaxel therapy. Nine repeated courses of this regimen have been given until now; the relapse of the abdominal wall invasion has not become apparent, and primary gastric lesion has been a stable disease. Diffuse abdominal wall invasion of gastric cancer like cuirass without ascites is a rare condition, and low-dose paclitaxel was very effective for this condition.

Abdominal Wall↗
PubMed2005

Genetic variations in the gene encoding TFAP2B are associated with type 2 diabetes mellitus.

To search a gene(s) conferring susceptibility to type 2 diabetes mellitus, we genotyped nearly 60,000 gene-based SNPs for Japanese patients and found evidence that the gene at chromosome 6p12 encoding transcription-factor-activating protein 2beta (TFAP2B) was a likely candidate in view of significant association of polymorphism in this gene with type 2 diabetes. Extensive analysis of this region identified that several variations within TFAP2B were significantly associated with type 2 diabetes [a variable number of tandem repeat locus: chi(2)=10.9, P=0.0009; odds ratio=1.57, 95% CI 1.20-2.06, intron 1+774 (G/T); chi(2)=11.6, P=0.0006; odds ratio=1.60, 95% CI 1.22-2.09, intron 1+2093 (A/C); chi(2)=12.2, P=0.0004; odds ratio=1.61, 95% CI 1.23-2.11]. The association of TFAP2B with type 2 diabetes was also observed in the UK population. These results suggest that TFAP2B might be a new candidate for conferring susceptibility to type 2 diabetes and contribute to the pathogenesis of type 2 diabetes.

Base Sequence↗
PubMed2005

Prevalence and risk factors for erectile dysfunction in Japanese diabetics.

We evaluated the prevalence and risk factors for erectile dysfunction (ED) and interest in ED treatment among Japanese men being treated for type 2 diabetes mellitus. Patients (40-79 years; n=1118) completed the 5-item version of the International Index of Erectile Function (IIEF-5), and questions related to interest in ED pharmacotherapy, subjective symptoms of diabetes, and general quality of life. A separate survey completed by physicians examined the relationships between age, diabetic treatments (insulin or oral), symptoms of diabetes (poor glycemic control, microangiopathy), complications of diabetes (hypertension, ischemic heart disease, cerebrovascular disease), and ED. The prevalence of ED in patients with diabetes was 90%, a rate double that of non-diabetic individuals. Multivariate analyses revealed that age, insulin therapy, microangiopathy, hypertension, history of cerebrovascular or cardiovascular disease, leg dysesthesia, dysuria, insomnia, and anorexia all represented significant risk factors for ED. Half of all respondents were interested (29%) or would consider pharmacotherapy for ED (21%). These findings suggest that ED is a significant problem in Japanese men with diabetes, and that specific risk factors increase the prevalence of ED. Furthermore, the survey results expose national attitudes toward treatment of ED.

Adult↗
PubMed2005

Genetic variants in the calpain-10 gene and the development of type 2 diabetes in the Japanese population.

Variation in the gene encoding the cysteine protease calpain-10 has been linked and associated with risk of type 2 diabetes. We have examined the effect of three polymorphisms in the calpain-10 gene (SNP-43, Indel-19, and SNP-63) on the development of type 2 diabetes in the Japanese population in a pooled analysis of 927 patients and 929 controls. We observed that SNP-43, Indel-19, and SNP-63 either individually or as a haplotype were not associated with altered risk of type 2 diabetes with the exception of the rare 111/221 haplogenotype (odds ratio (OR) =3.53, P=0.02). However, stratification based on the median age-at-diagnosis in the pooled study population (<50 and > or =50 years) revealed that allele 2 of Indel-19 and the 121 haplotype were associated with reduced risk in patients with later age-at-diagnosis (age-at-diagnosis > or =50 years OR=0.82 and 0.80, respectively; P=0.04 and 0.02). Thus, variation in the calpain-10 gene may affect risk of type 2 diabetes in Japanese, especially in older individuals.

Adult↗
PubMed2005

Chorea and Broca aphasia induced by diabetic ketoacidosis in a type 1 diabetic patient diagnosed as Moyamoya disease.

We here report one case of hemichorea and Broca aphasia occurred with diabetic ketoacidosis. A 20-year-old woman with type 1 diabetes mellitus had experienced diabetic ketoacidosis fourth time after the onset of diabetes. At the third ketoacidotic episode, the patient was admitted to our hospital for the first time to show hemichorea of the left extremities. Brain computed tomography (CT) demonstrated a high-density area in the right caudate head and low-density area in the right putamen. Magnetic resonance angiography (MRA) demonstrated a stenosis at the root of the bilateral middle and anterior cerebral arteries. The hemichorea disappeared within 3 days. At the fourth ketoacidotic episode, not hemichorea but unconsciousness was there for 2 days even after ketoacidosis disappeared. After the unconscious state, Broca aphasia was demonstrated for 15 days. The cerebral angiography showed a finding compatible to Moyamoya disease. These findings support that chorea and Broca aphasia induced by diabetic ketoacidosis was developed in addition to blood vessel abnormalities such as Moyamoya disease. We suggest that poorly controlled diabetic patients with hemichorea should undergo cerebral angiography.

Adult↗
PubMed2005

Genetic variations in the gene encoding ELMO1 are associated with susceptibility to diabetic nephropathy.

To search for a gene(s) conferring susceptibility to diabetic nephropathy (DN), we genotyped over 80,000 gene-based single nucleotide polymorphisms (SNPs) in Japanese patients and identified that the engulfment and cell motility 1 gene (ELMO1) was a likely candidate for conferring susceptibility to DN, in view of the significant association of an SNP in this gene with the disease (intron 18+9170, GG vs. GA+AA, chi(2) = 19.9, P = 0.000008; odds ratio 2.67, 95% CI 1.71-4.16). In situ hybridization (ISH) using the kidney of normal and diabetic mice revealed that ELMO1 expression was weakly detectable mainly in tubular and glomerular epithelial cells in normal mouse kidney and was clearly elevated in the kidney of diabetic mice. Subsequent in vitro analysis revealed that ELMO1 expression was elevated in cells cultured under high glucose conditions (25 mmol/l) compared with cells cultured under normal glucose conditions (5.5 mmol/l). Furthermore, we identified that the expression of extracellular matrix protein genes, such as type 1 collagen and fibronectin, were increased in cells that overexpress ELMO1, whereas the expression of matrix metalloproteinases was decreased. These results indicate that ELMO1 is a novel candidate gene that both confers susceptibility to DN and plays an important role in the development and progression of this disease.

Adaptor Proteins, Signal Transducing↗