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T Takamura

Publications and source records attributed to T Takamura.

At least 37 records · Page 2Linked to original sources
PubMed2000

Gln27Glu and Arg16Gly polymorphisms of the beta2-adrenergic receptor gene are not associated with obesity in Japanese men.

The beta2-adrenergic receptor (beta2AR), beta3AR, or uncoupling protein 1 (UCP1) may play a pathogenic role in obesity. In Swedish Caucasians, a polymorphism at codon 27 (Gln27Glu) of the beta2AR gene was shown to be associated with obesity, but no such association was shown for a polymorphism of codon 16 (Arg16Gly). Thus, we investigated whether these polymorphisms contribute to obesity in 210 Japanese men. The frequencies of the Gln27Glu and Arg16Gly polymorphisms were 0.05 and 0.48, respectively, and there was no association with obesity. A strong linkage disequilibrium between the Gln27Glu and Arg16Gly polymorphisms was shown, but there was no apparent additive effect on the clinical or metabolic characteristics. Our results suggest that the Gln27Glu and Arg16Gly polymorphisms of the beta2AR gene are not a major contributing factor to obesity in Japanese men.

Adult↗
PubMed2000

Plasma levels of vascular endothelial growth factor in patients with acromegaly.

Vascular endothelial growth factor (VEGF) is known to be linked to retinal ischemia-associated neovascularization. It was recently found that insulin-like growth factor-I (IGF-I) enhances VEGF gene expression. In this study we investigated whether plasma VEGF levels are increased in patients with acromegaly, a disease in which plasma IGF-I levels are elevated, and whether plasma VEGF levels are correlated with plasma IGF-I levels in these patients. We retrospectively analyzed plasma samples from 13 active acromegalic patients (7 males and 6 females) aged 33 to 66 years, with a mean age of 52.3+/-10.8 years. The results were compared with plasma VEGF levels in 16 age- and sex-matched, healthy subjects (9 males and 7 females) aged 22 to 66 years, with a mean age of 52.4+/-11.5 years. Plasma VEGF levels were not higher in the acromegalic patients than in the healthy subjects (253+/-61 vs. 197+/-30 pg/mL, P= 0.39). In 5 patients plasma VEGF levels were rather slightly increased after pituitary adenomectomy while one patient showed a reduced plasma VEGF level. In addition there was no correlation between plasma VEGF and GH or IGF-I levels. These data indicate that plasma VEGF levels are not increased in patients with acromegaly and that serum VEGF may play a less important role in the neovascularization in the carcinogenesis and/or disturbances of the cardiovascular system in patients with acromegaly.

Acromegaly↗
PubMed2000

Metabolism of 26,27-hexafluoro-1 alpha,25-dihydroxyvitamin D3 and 26,27-hexafluoro-1 alpha,23(S)25-trihydroxyvitamin D3 in ROS17/2.8 cells transfected with a plasmid expressing CYP24.

1. To clarify the possibility that the metabolism of 26,27-hexafluoro-1 alpha,25-dihydroxyvitamin D3 [F6-1,25(OH)2D3] to 26,27-hexafluoro-1 alpha,23(S),25-trihydroxyvitamin D3 [F6-1,23,25(OH)3D3 and that of F6-1,23,25(OH)3D3 to 26,27-hexafluoro-23-oxo-1 alpha,25-dihydroxyvitamin D3 [F6-23-oxo-1,25(OH)2D3] are catalysed by 25-hydroxyvitamin D3 24-hydroxylase (CYP24), ROS17/2.8 cells transfected with a plasmid expressing CYP24 [pSVL-CYP24(+)] and a corresponding blank plasmid [pSLV-CYP24R(-)] were used. 2. Incubation of [1 beta-3H]-F6-1,25(OH)2D3 for 2 and 5 days with ROS17/2.8 cells transfected with pSVL-CYP24(+) generated a metabolite that co-migrated with authentic F6-1,23,25(OH)3D3 in both normal phase and reversed-phase HPLC systems. 3. Incubation of [1 beta-3H]-F6-1,23,25(OH)3D3 for 5 days with pSVL-CYP24(+)- transfected ROS 17/2.8 cells generated a metabolite that co-migrated with authentic F6-23-oxo-1,25(OH)2D3. In contrast, the metabolites F6-1,23,25(OH)3D3 or F6-23-oxo-1,25(OH)2D3 were not generated in the cells transfected with pSVL-CYP24R(-). 4. The results indicate that CYP24 catalyses the conversion of F6-1,25(OH)2D3 to F6-1,23,25(OH)3D3 and that of F6-1,23,25(OH)3D3 to F6-23-oxo-1,25(OH)2D3.

Animals↗
PubMed2000

Cerivastatin improves survival of mice with lipopolysaccharide-induced sepsis.

Development of severe sepsis is thought to result from the overproduction of cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), and nitric oxide. Recently, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, which are antihypercholesterolemic agents, have been reported to inhibit lipopolysaccharide (LPS)-induced production of cytokines and nitric oxide in vitro. In this study, we tested these effects in vivo. After LPS administration (15 mg/kg i.p.) to CD-1 mice, serum levels of both TNF-alpha and IL-1beta transiently increased, and peaked at 2 h. After the peak responses of TNF-alpha and IL-1beta, serum levels of nitrite and nitrate increased until at least 8 h. Pretreatment of the mice with cerivastatin (20 mg/kg i.p. 12 and 1 h before LPS injection) reduced serum levels of TNF-alpha and IL-1beta at 2 h, and nitrite and nitrate at 8 h, by 93, 60, and 44%, respectively. In this model of sepsis, cerivastatin significantly (P =.016) improved the rate of 7-day survival from 26.7 to 73.3%. These results cast new light on the usefulness of cerivastatin in preventing severe sepsis.

Animals↗
PubMed1999

Angiotensin II receptor blockade limits kidney injury in two-kidney, one-clip Goldblatt hypertensive rats with special reference to phenotypic changes.

Recent evidence indicates that tubulointerstitial injury plays an important role in hypertensive kidney injury and that phenotypic changes contribute to this pathology. Moreover, angiotensin II is known to be actively involved in the pathogenesis of progressive kidney injury induced by hypertension. The present study was undertaken to see the effect of a newly developed angiotensin II type I receptor (AT1 receptor) antagonist on hypertension-induced kidney injury and to determine the contribution of phenotypic changes to morphologic alterations. Two-kidney, one-clip (2K1C), Goldblatt hypertensive rats (n = 27) were made by clipping the left renal artery. These animals were orally administered 57G709 (a selective non-peptide AT1 receptor antagonist)(10 mg/kg/day), captopril (20 mg/kg/day), or vehicle alone for 23 days beginning 4 weeks after clipping. In the non-clipped kidney of vehicle-treated 2K1 C rats, marked tubulointerstitial injury as well as glomerular sclerosis and/or hyalinosis was found in association with phenotypic changes, as shown by the neoexpression of vimentin in periglomeruli, perivascular walls, distal tubuli, and injured interstitium. Renin expression was markedly suppressed in the non-clipped kidneys of vehicle-treated 2K1C rats as compared with renin expression in normotensive control kidneys of sham-operated rats. Both 57G709 and captopril markedly ameliorated hypertensive kidney injury as reflected by the glomerular sclerosing index and by the tubulointerstitial index as determined by the point-counting method, and this improvement was accompanied by a significant decrease in blood pressure, urinary protein excretion, kidney/body weight ratio, and heart/body weight ratio. In addition, the vimentin neoexpression mentioned above was also suppressed with an inhibition of angiotensin II. These results suggest that in 2K1C Goldblatt hypertensive kidney injury, the AT1 receptor antagonist 57G709 exerts a potent renal protective effect associated with the inhibition of phenotypic changes.

Angiotensin Receptor Antagonists↗
PubMed1999

Phenotypic characterization of the beta3-adrenergic receptor mutation and the uncoupling protein 1 polymorphism in Japanese men.

The Trp64Arg mutation of the beta3-adrenergic receptor (beta3AR) gene and A to G polymorphism of the uncoupling protein 1 (UCP1) gene are reported to be associated with weight gain, and both have been shown to have an additive effect on weight gain in Caucasians. Racial differences have also been noted in the beta3AR mutation; however, the effect of UCP1 polymorphism on body weight is not obvious in the Japanese. Thus, we investigated the association of genetic variations in beta3AR and UCP1 genes and the additive effects of these two genes in 214 Japanese men. The frequency of the Trp64Arg allele was 0.19, and serum triglyceride was significantly higher in Arg64 homozygotes versus Trp64 homozygotes. The frequency of the G allele was 0.51, and the body mass index (BMI) was significantly higher in subjects with the G allele (GG homozygotes and AG heterozygotes) versus those without it (AA homozygotes). The beta3AR mutation and UCP1 polymorphism were not found to have additive effects, and they were not related to glucose tolerance patterns and insulin resistance. Our results suggest that the beta3AR mutation is associated with hypertriglyceridemia and the UCP1 polymorphism may be a weak contributing factor to obesity in Japanese men.

Adult↗
PubMed1999

Variation of the fatty acid binding protein 2 gene is not associated with obesity and insulin resistance in Japanese subjects.

An alanine to threonine substitution at codon 54 of the fatty acid binding protein 2 (FABP2) gene has been associated with insulin resistance in Pima Indians and with obesity in aboriginal Canadians. We investigated whether this polymorphism contributes to obesity and insulin resistance in 258 Japanese subjects. Thirty-six subjects (13.9%) were homozygous for the Thr54 allele, 106 (41.1%) were heterozygous for the Ala54/Thr54 allele, and 116 (45.0%) were homozygous for the Ala54 allele. The frequency of the Thr54 allele was 0.34 and did not differ significantly between men and women. The incidence of non-insulin-dependent diabetes mellitus (NIDDM) was not different among the three genotypes. The variation at codon 54 of the FABP2 gene was not associated with obesity, hypertension, dyslipidemia, hyperuricemia, or hyperinsulinemia. These results suggest that the polymorphism at codon 54 of the FABP2 gene is not a major contributing factor to obesity and insulin resistance in Japanese subjects.

Adult↗
PubMed1999

Pioglitazone prevents mice from multiple low-dose streptozotocin-induced insulitis and diabetes.

Macrophage infiltration into pancreatic islets is thought to be an initial event inducing insulitis in the development of type 1 diabetes. Thiazolidinedione is a direct ligand for peroxisome proliferator-activated receptor-gamma, recently reported to inhibit macrophage activation, including cytokine production and type 2 nitric oxide synthase expression. We investigated the effect of pioglitazone, a thiazolidinedione compound, on the development of multiple low-dose streptozotocin (MLDS)-induced autoimmune diabetes in mice. CD-1 mice intraperitoneally injected with five daily sub-diabetogenic doses (30 or 40 mg/kg body weight) of streptozotocin developed mononuclear cell infiltration in and around islets, followed by hyperglycemia. Oral administration of pioglitazone (0.01% food admixture) from 7 days before the first streptozotocin injection prevented or delayed the development of diabetes induced by MLDS. Histologically, pioglitazone blocked the infiltration of mononuclear cells into islets in MLDS mice. Peritoneal macrophages from MLDS mice at day-7 produced significantly large amount of nitric oxide compared with those from control mice. Such activation of peritoneal macrophages was not observed in pioglitazone-treated MLDS mice. These findings suggest that pioglitazone blocks the autoimmune process in the development of MLDS diabetes, partly by inhibiting the macrophage activation.

Administration, Oral↗
PubMed1999

Adrenal insufficiency due to metastatic hepatocellular carcinoma.

A 73-year-old man with general malaise and nausea following a common cold diagnosed by a local physician was found to have multiple hepatocellular carcinomas with enlarged bilateral adrenal glands, combined with adrenal insufficiency. Hydrocortisone replacement improved the symptoms and laboratory findings. Autopsy findings revealed that each adrenal gland was completely replaced by the tumor measuring 11 cm in diameter, and no adrenal tissue was recognized. Histologically, the adrenal tumors, as well as the liver tumors, were moderately differentiated Edmondson type II hepatocellular carcinomas. This is a second report of adrenal insufficiency due to hepatocellular carcinoma as a primary site of metastatic adrenal tumor.

Adrenal Gland Neoplasms↗
PubMed1999

[Effects of gadobenate dimeglumine on MRI of mouse liver metastasis model constructed by orthotopic transplantation of highly metastatic murine colon carcinoma (C38-OT7): comparison with gadopentetate dimeglumine].

Twelve mice with metastatic liver tumors were divided into two groups of six, with one group administered contrast medium at 0.1 mmol/kg, and the other at 0.2 mmol/kg. Contrast medium, gadobenate dimeglumine (GD) or gadopentetate dimeglumine (GP), was administered at 0.1 or 0.2 mmol/kg via the tail vein to each animal in each group. Using a Signa Horizon 1.5-Tesla MRI unit, spin-echo transverse and coronal T1-weighted sections were obtained every 15 minutes until 2 hours after administration. The numbers of liver tumors detected on films were counted before and after the administration of contrast medium, and the liver/tumor contrast-to-noise ratio (CNR) was calculated. After the completion of MRI, livers were removed, and the number of metastatic nodules on the liver surface were counted as the number of tumors. Liver/tumor CNR rose after administration in both of the GD groups. In the GP group, liver/tumor CNR remained almost constant throughout the observation period. Relative to the number of tumors detected at optical microscopy, approximately 80% and 100% of tumors were detected at MRI after the administration of GD at 0.1 and 0.2 mmol/kg, respectively. On the other hand, approximately similar numbers of tumors were detected at MRI before and after the administration of GP. These results suggest that GD administered by intravenous injection was transported promptly to the liver, increased liver/tumor CNR, and enhanced detection performance for metastatic liver tumor.

Animals↗
PubMed1998

Transgenic mice overexpressing type 2 nitric-oxide synthase in pancreatic beta cells develop insulin-dependent diabetes without insulitis.

We generated transgenic mice carrying the mouse type 2 nitric-oxide synthase (NOS2) cDNA under the control of the insulin promoter. Western and immunohistochemical analyses revealed that NOS2 was expressed abundantly in transgenic islets but not in control islets. When islets were isolated and cultured, high levels of nitrite were released from the transgenic islets. In transgenic mice, the beta cell mass was markedly reduced without the infiltration of macrophages or lymphocytes, and extensive DNA strand breaks were detected in the islets by in situ nick translation. All the transgenic mice developed hypoinsulinemic diabetes by 4 weeks of age, and treatment with an inhibitor of NOS2, aminoguanidine (200 mg/kg body weight every 12 h), prevented or delayed the development of diabetes. The present study shows that the production of nitric oxide by beta cell NOS2 plays an essential role in the beta cell degeneration.

Animals↗
PubMed1998

Elevated serum levels of soluble vascular cell adhesion molecule-1 in NIDDM patients with proliferative diabetic retinopathy.

We studied 68 Japanese NIDDM patients (38 men and 30 women), aged 56.9+/-1.2 years (range 33-75 years), with a BMI of 23.1+/-0.5 kg/m2 without hypertension, dyslipidemia, and diabetic macroangiopathy for evaluating the relationship between serum soluble vascular cell adhesion molecule-1 (sVCAM-1) levels and the severity of diabetic retinopathy. Fundus examination was performed by an ophthalmologist using an ophthalmoscope, and the findings were graded as: (1) no signs of diabetic retinopathy (NDR), (2) background diabetic retinopathy (BDR), or (3) proliferative diabetic retinopathy (PDR). Serum sVCAM-1 levels were measured in duplicate by enzyme-linked immunosorbent assay using the soluble VCAM-1 KIT (R&D Systems Ltd., Ablingdon, Oxfordshire, UK). There was no difference in serum sVCAM-1 levels between patients with BDR (n = 17) and patients with NDR (n = 40) (1035.3+/-104.4 and 978.8+/-48.9 ng/ml, respectively, P = 0.8), but patients with PDR (n = 11) showed a significant increase of serum sVCAM-1 levels compared with patients with NDR (1281.8+/-166.3 and 978.8+/-48.9 ng/ml, respectively, P = 0.02). Although serum sVCAM-1 levels were correlated, not only with age but also with the known diabetic duration (r = 0.39, P = 0.001, and r = 0.40, P = 0.0007, respectively), age-adjusted sVCAM-1 levels were still significantly higher in the PDR group than in the NDR group. In contrast. serum sVCAM-1 levels were not related to the presence of diabetic nephropathy or HbA1c levels. Our results suggest that sVCAM-1 might be implicated in the development of the diabetic retinopathy, and measurement of serum sVCAM-1 levels in NIDDM patients maybe clinically useful for assessing the severity and possibly the activity of diabetic retinopathy.

Adult↗