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Biomedical subjects

Keigo Yasuda

Publications and source records attributed to Keigo Yasuda.

35 records · Page 2Linked to original sources
PubMed2003

Role of local 11 beta-hydroxysteroid dehydrogenase type 2 expression in determining the phenotype of adrenal adenomas.

It is not understood why some adrenal adenomas are nonfunctional and others with similar histopathology cause preclinical or overt Cushing's syndrome. Two isozymes of 11 beta-hydroxysteroid dehydrogenase, types 1 and 2 (HSD11B1 and HSD11B2), are known to modulate glucocorticoid levels in other tissues and might influence circulating levels of active and inactive glucocorticoids if they were expressed in adrenal adenomas. We determined levels of expression of these isozymes in normal adrenals and 61 adrenal adenomas by quantitative competitive RT-PCR and immunohistochemistry. There were no differences in HSD11B1 mRNA levels among adrenal tumor groups. HSD11B2 mRNA levels were high in nonfunctioning adenomas and preclinical Cushing's adenomas compared with levels in control adrenals or in adenomas causing overt Cushing's syndrome. HSD11B2 immunoreactivity was not detected in control adrenals, but was observed in more than half of these tumors. When nonfunctioning adenomas and those causing preclinical and overt Cushing's syndrome were considered as a single group, HSD11B2 mRNA levels were strongly correlated with the ratio of plasma cortisone to cortisol, and a simple model incorporating adrenal HSD11B2 expression and tumor size as variables could predict more than 50% of the interindividual variation in plasma cortisol levels (r(2) = 0.54; P < 0.0001). Adrenal HSD11B2 may regulate levels of active and inactive glucocorticoids in the systemic circulation under these conditions, presumably by acting in an autocrine or paracrine manner. Nonfunctioning adenomas and those causing preclinical and overt Cushing's syndrome may represent a continuum with clinical manifestations depending mainly on tumor size and HSD11B2 expression levels.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed2003

Micro-analytical identification, by NMR, of elevated steroid in urine of Cushing's syndrome patients.

We previously reported that the daily urinary unidentified ketosteroid glucuronide (US-G) level in patients with Cushing's syndrome was much higher than that in the healthy subjects. Furthermore, urine samples from patients with Cushing's syndrome, including those with pituitary adenoma and adrenal adenoma, yielded almost the same high excretion levels, despite the different sites of the adenomas. We extracted US obtained by hydrolysis of US-G in urine of patients with Cushing's syndrome, purified it, and analyzed its chemical structure. Molecular weight and molecular formula were analyzed by MS spectrometry, and the chemical structure was analyzed by NMR spectrometry, utilizing small quantities of refined US. The substance has a molecular weight of 304 Da, a molecular formula of C19H28O3, and its chemical structure is 3alpha,11beta-dihydroxyandrost-4-en-17-one.

17-Ketosteroids↗
PubMed2003

Decrease of beta-cells and increase of alpha-cells in a diabetic patient with mitochondrial DNA 3243 (A-->G) mutation.

We report here a case of a 53-year-old woman with mitochondrial 3243 (A-->G) mutation diabetes. Diabetes mellitus was diagnosed at 39 years of age. At 50 years of age, cardiomyopathy and hypothyroidism were noted. At 53 years of age, the patient was admitted to our hospital for treatment of necrotic ulceration of toes. However, she died of massive heart failure. Pathological examination at autopsy showed a decrease in size, number, and acidophilicity of islets in the pancreas. Immunohistochemical stain revealed a decrease in the beta-cell population to 20.5+/-9.2% and a relative increase in alpha-cell population to 48.6+/-11.5%.

Cardiomyopathy, Dilated↗
PubMed2002

Leptin and high glucose stimulate cell proliferation in MCF-7 human breast cancer cells: reciprocal involvement of PKC-alpha and PPAR expression.

Glucose concentration may be an important factor in breast cancer cell proliferation, and the prevalence of breast cancer is high in diabetic patients. Leptin may also be an important factor since plasma levels of leptin correlated with TNM staging for breast cancer patients. The effects of glucose and leptin on breast cancer cell proliferation were evaluated by examining cell doubling time, DNA synthesis, levels of cell cycle related proteins, protein kinase C (PKC) isozyme expression, and peroxisome proliferator-activated receptor (PPAR) subtypes were determined following glucose exposure at normal (5.5 mM) and high (25 mM) concentrations with/without leptin in MCF-7 human breast cancer cells. In MCF-7 cells, leptin and high glucose stimulated cell proliferation as demonstrated by the increases in DNA synthesis and expression of cdk2 and cyclin D1. PKC-alpha, PPARgamma, and PPARalpha protein levels were up-regulated following leptin and high glucose treatment in drug-sensitive MCF-7 cells. However, there was no significant effect of leptin and high glucose on cell proliferation, DNA synthesis, levels of cell cycle proteins, PKC isozymes, or PPAR subtypes in multidrug-resistant human breast cancer NCI/ADR-RES cells. These results suggested that hyperglycemia and hyperleptinemia increase breast cancer cell proliferation through accelerated cell cycle progression with up-regulation of cdk2 and cyclin D1 levels. This suggests the involvement of PKC-alpha, PPARalpha, and PPARgamma.

Breast Neoplasms↗
PubMed2002

Effect of 1 alpha,25-dihydroxy vitamin D3 and vitamin E on insulin-induced glucose uptake in rat adipocytes.

Vitamin E, an antioxidant, improves insulin sensitivity through the suppression of conventional PKC in vascular smooth muscle cells. It has been reported that vitamin E reduces platelet aggregation through the suppression of PKC alpha and beta (Diabetes 47 (1998) 1494). On the other hand, 1 alpha,25-dihydroxy vitamin D3 (1,25D3) activates conventional PKC and may subsequently cause insulin resistance. Against this background, we examined the effect of vitamin E and 1,25D3 on PKC beta and PKC zeta/lambda activities in vitro and 10 nM insulin-induced glucose uptake in rat adipocytes. In vitro PKC beta activity of adipocytes was slightly decreased by the addition of 1 microM vitamin E, but not PKC zeta/lambda activity. In contrast, a 10-1000 nM 1,25D3 dose responsively activated PKC beta activity of adipocytes (ED 50%, 10 nM), but not PKC zeta/lambda activity. Pretreatment with 1 microM vitamin E for 60 min did not improve the insulin-induced glucose uptake. On the other hand, pretreatment with a 10-1000 nM 1,25D3 dose responsively suppressed insulin-induced glucose uptake. Moreover, 1,25D3 increased membrane-associated PKC beta immunoreactivity for 60 min, but no additional increase in membrane-associated PKC beta immunoreactivity during treatment with insulin was observed. These results suggest that 1,25D3 reduces insulin-induced glucose uptake via activation of PKC beta, but not vitamin E in rat adipocytes.

Adipocytes↗
PubMed2002

Glycyrrhizic acid suppresses type 2 11 beta-hydroxysteroid dehydrogenase expression in vivo.

Licorice-derivatives such as glycyrrhizic acid (GA) competitively inhibit 11 beta-hydroxysteroid dehydrogenase(11 beta-HSD) type 2 (11-HSD2) enzymatic activity, and chronic clinical use often results in pseudoaldosteronism. Since the effect of GA on 11-HSD2 expression remains unknown, we undertook in vivo and in vitro studies. Male Wistar rats were given 30, 60 or 120 mg/kg of GA twice a day for 2 weeks. Plasma corticosterone was decreased in those given the 120 mg dose, while urinary corticosterone excretion was increased in those given the 30 and 60 mg doses but decreased in those given 120 mg GA. NAD(+)-dependent dehydrogenase activity in kidney microsomal fraction was decreased in animals receiving doses of 60 and 120 mg GA. The 11-HSD2 protein and mRNA levels were decreased in those given 120 mg GA. In contrast, in vitro studies using mouse kidney M1 cells revealed that 24h treatment with glycyrrhetinic acid did not affect the 11-HSD2 mRNA expression levels. Thus, in addition to its role as a competitive inhibitor of 11-HSD2, the chronic high dose of GA suppresses mRNA and protein expression of 11-HSD2 possibly via indirect mechanisms. These effects may explain the prolonged symptoms after cessation of GA administration in some pseudoaldosteronism patients.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2002

Inhibition of PKCbeta improves glucocorticoid-induced insulin resistance in rat adipocytes.

Pretreatment with glucocorticoids for 60 min depressed insulin-stimulated uptake of 2-[3H] deoxyglucose (2-DOG), an effect that neither cycloheximide, an inhibitor of protein synthesis, nor RU38486, a glucocorticoid receptor antagonist, could restore. Preincubation with conventional PKC inhibitors restored dexamethasone-induced insulin resistance. We also examined the dexamethasone-mediated inhibitory effect on insulin-induced 2-DOG uptake in adipocytes overexpressed with wild-type and dominant negative forms of PKCbeta. The dexamethasone-mediated inhibitory effect on insulin-induced 2-DOG uptake was abrogated in adipocytes overexpressed with dominant-negative PKCbeta. These results indicate that PKCbeta may play an important role in glucocorticoid-induced insulin resistance.

Adipocytes↗
PubMed2002

Transient Graves disease developing after surgery for Cushing disease.

A 49-year-old man, diagnosed as having Cushing disease in 1976 at the age of 26, underwent a Hardy operation 13 years after treatment with reserpine combined with pituitary radiation. In laboratory examinations before and 2 weeks after the successful surgery, the patient's serum thyroid hormones were found to be normal except for suppressed serum thyroid-stimulating hormone (TSH), and his serum anti-TSH receptor (TRAb) and anti-TSH receptor-stimulating antibodies (TSAb) were negative. Glucocorticoid supplemental treatment was withdrawn on the 15th day after surgery and was restarted on the 48th day, during which time there were no signs of an adrenal crisis. Sinus tachycardia, fine finger tremor, and enlarged thyroid gland, approximately the size of a thumb head, were observed on the 140th day after surgery. Thyrotoxicosis with increased serum TSAb and TRAb and high 24-h thyroid uptake of 123I was noted, indicating a diagnosis of Graves disease. No special treatment was prescribed, but his serum thyroid hormone levels started to decrease on the 140th day after the operation and returned to normal on the 520th day. Serum TRAb also spontaneously decreased, but the timing of the peak of serum TRAb was delayed 230 days from that of the thyroid hormones. This is the first reported case of Graves disease after successful surgery for Cushing disease. We presume that a latent autoimmune process in the thyroid, suppressed by hypercortisolism, developed into overt Graves disease after the abrupt reduction of plasma glucocorticoid levels induced by surgery.

Adult↗
PubMed2002

Severe graves ophthalmopathy accompanied by HTLV-1-associated uveitis (HAU) and anti-neutrophil cytoplasmic antibody-related vasculitis: a case report and a review of the literature of HAU with Graves disease.

A 50-year-old woman was admitted because of severe exophthalmos associated with Graves disease. She underwent methimazole (MMI) and methylprednisolone pulse therapy against exophthalmos. She noticed photophobia and blurred vision 3 weeks after the start of pulse therapy and she was diagnosed as having uveitis. Methylprednisolone pulse therapy was performed again for both exophthalmos and uveitis, followed by daily administration of 20 mg of prednisolone and instillation of betamethasone for 2 weeks and the uveitis was improved. Western blot analysis confirmed that human T lymphotropic virus type 1 (HTLV-1) antibody was present in her serum. Propylthiouracil was substituted for MMI and HTLV-1-associated uveitis (HAU) has not recurred. Six months after the beginning of administration of PTU, anti-neutrophil cytoplasmic antibody-related vasculitis developed in the patient. We review 43 cases of HAU with Graves disease, including the present case, in the literature. Only 2 of 27 cases (except unknown cases) (7.4%) had Graves ophthalmopathy. To the best of our knowledge, there has been no investigation of HAU and Graves ophthalmopathy.

Anti-Inflammatory Agents↗
PubMed2002

High glucose inhibits apoptosis in human coronary artery smooth muscle cells by increasing bcl-xL and bfl-1/A1.

Cardiovascular disease is a serious complication in diabetic patients. To elucidate the precise mechanisms of atherosclerosis in diabetic patients, the effects of high glucose concentration (25 mM) on apoptosis regulation and bcl-2 family protein expression in human coronary artery smooth muscle cells (CASMC) were examined. Treatment with a high level of glucose (25 mM) caused a significant decrease in apoptosis in CASMC compared with the same cells treated with a physiologically normal glucose concentration (5.5 mM) (23.9 +/- 2.4% vs. 16.5 +/- 1.8%; P < 0.01). With respect to apoptosis regulation, treatment of CASMC with high glucose concentration markedly increased mRNA expressions of bcl-xL and bfl-1/A1 compared with cells treated with normal glucose. High glucose induced phosphorylation of phosphatidylinositol 3-kinase (PI 3-K) and extracellular signal-regulated kinase (ERK)1/2 along with bcl-xL and bfl-1/A1 upregulation. These results suggest that high glucose suppresses apoptosis via upregulation of bcl-xL and bfl-1/A1 levels through PI 3-K and ERK1/2 pathways in CASMC. High glucose-induced increase in the expression of antiapoptotic proteins may be important in the development of atherosclerosis in diabetic patients.

Apoptosis↗
PubMed2002

Altered corticosteroid metabolism differentially affects pituitary corticotropin response.

To evaluate the effects of altered corticosteroid metabolism on the hypothalamic-pituitary-adrenal axis, we examined rats treated with glycyrrhizic acid (G rats) or rifampicin (R rats) for 7 days. The half-life of exogenously administered hydrocortisone as a substitute for corticosterone was longer in G rats and shorter in R rats, with no differences in basal plasma levels of ACTH or corticosterone. The ACTH responses to human corticotropin-releasing factor (CRF) or insulin-induced hypoglycemia were greater in G rats and tended to be smaller in R rats compared with those in the control rats, whereas the corticosterone response was similar. No difference was observed in the content and mRNA level of hypothalamic CRF among the groups. The number and mRNA level of CRF receptor and type 1 11 beta-hydroxysteroid dehydrogenase (11-HSD1) mRNA level in the pituitary were increased in G rats but not changed in R rats, suggesting that chronically increased intrapituitary corticosterone upregulates pituitary CRF receptor expression. In contrast, CRF mRNA levels in the pituitary were increased in R rats. Our data indicate novel mechanisms of corticosteroid metabolic modulation and the involvement of pituitary 11-HSD1 and CRF in glucocorticoid feedback physiology.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2002

Eutopic overexpression of vasopressin v1a receptor in adrenocorticotropin-independent macronodular adrenal hyperplasia.

Arginine vasopressin (AVP) stimulates cortisol secretion through its vascular type V(1a) receptor in the adrenal glands, in addition to stimulating ACTH secretion through pituitary V(3) receptor. Because hyper-response of plasma cortisol to vasopressin is documented in some patients with Cushing's syndrome due to adrenal adenoma (CS) or ACTH-independent macronodular adrenocortical hyperplasia (AIMAH), we analyzed the expression of V(1a), V(2), V(3) receptor and AVP mRNA in human adrenal tissues by quantitative competitive RT-PCR or real-time PCRs. V(1a) receptor mRNA levels (ratio against glyceraldehyde 3-phosphate dehydrogenase) were 0.378 +/- 0.143 (mean +/- SE) in preclinical CS (n = 5) and 0.630 +/- 0.072 in AIMAH (n = 4), which were significantly higher than those (0.046 +/- 0.012; n = 9) in control adrenals, whereas those in overt CS (0.143 +/- 0.048; n = 10) or aldosterone-producing adenomas (0.069 +/- 0.018; n = 12) were similar to control adrenals. Although ectopic expression of V(2) or V(3) receptor was detected in half of AIMAH cases, the absolute levels were low. Furthermore, V(1a) receptor mRNA levels in the adjacent adrenal glands (0.190 +/- 0.039, n = 9) of aldosterone-producing adenomas were higher than those in control adrenals and in the corresponding tumor portions (0.079 +/- 0.024). In contrast, there were no significant differences in AVP mRNA levels among these groups. These results suggest that eutopic V(1a) receptor overexpression is involved in the etiology of AIMAH and a subset of adrenal adenomas causing overt or preclinical Cushing's syndrome. Our results imply a possible association of V(1a) receptor expression with adrenal hyperplasia.

Adrenal Gland Diseases↗
PubMed2002

Variant of pre-clinical Cushing's syndrome: hypertension and hypokalemia associated with normoreninemic normoaldosteronism.

The case of a 48-year-old woman with a left adrenocortical adenoma and showing hypokalemia, hypertension and normoreninemic normoaldosteronism is reported. Basal plasma adrenocorticotrophic hormone (ACTH) and cortisol levels were within the reference ranges. The patient's plasma cortisol level decreased insufficiently at night, and was insufficiently decreased by nighttime administration of dexamethasone. She showed no Cushingnoid stigmata. Iodocholesterol scintigraphy revealed tumor-sided uptake alone. The plasma dehydroepiandrosterone-sulfate level was low-to-normal for her age. Metabolic alkalosis and increased potassium clearance after sodium thiosulfate loading were revealed. The plasma aldosterone level was within the normal range, but it was statistically higher than the range for patients with pre-clinical Cushing's syndrome. However, peripheral plasma renin activity (PRA) increased normally after the patient resumed an upright posture following furosemide administration. After adenomectomy the hypokalemia and hypertension were resolved, and the plasma ACTH, cortisol, and PRA remained within the reference ranges. The plasma aldosterone level decreased slightly, but also remained within the reference range after adenomectomy. Paradoxical hyperplasia in the non-neoplastic adrenal glomerulosa zone, which indicates primary aldosteronism, and slight atrophy of the non-neoplastic adrenal cortex, which indicates pre-clinical Cushing's syndrome, were demonstrated. These findings satisfied the criteria of pre-clinical Cushing's syndrome, but did not completely satisfy those of primary aldosteronism. However, the level of CYP11 B2 mRNA in the tumor was in the lower-limit of the range for adenomas associated with primary aldosteronism and was higher than the ranges for adenomas associated with pre-clinical Cushing's syndrome and overt Cushing's syndrome. Based on these results, this case was suspected to constitute a variant of pre-clinical Cushing's syndrome with slight hypersecretion of aldosterone.

Adenoma↗
PubMed2002

Effects of dietary treatment alone or diet with voglibose or glyburide on abdominal adipose tissue and metabolic abnormalities in patients with newly diagnosed type 2 diabetes.

UNLABELLED: OBJECTIVE; To examine the effects of diet and diet with voglibose or glyburide on abdominal adiposity and metabolic abnormalities in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 36 Japanese patients with newly diagnosed type 2 diabetes (50.8 +/- 8.6 years of age, BMI 24.5 +/- 3.5 kg/m(2)) and 273 normal control subjects were studied. The patients were treated for 3 months with diet alone (30 kcal/kg per day) (n = 15), diet with voglibose (n = 12), or diet with glyburide (n = 9). They underwent 75-g oral glucose tolerance testing, assessment of insulin sensitivity (SI), and acute insulin response (AIR) with intravenous glucose tolerance testing based on the minimal model, and measurement of abdominal visceral adipose tissue area (VAT) and subcutaneous adipose tissue area (SAT) by computed tomography before and after treatment. RESULTS: The diabetic patients had comparable SAT but larger VAT than the control subjects. With a mean weight loss of 2-3 kg, VAT and SAT were decreased similarly in all treatment groups. The VAT-to-SAT ratio was decreased only in the voglibose group. Glycemic control and serum lipid profiles were improved in all groups. Changes in glycemic control after diet were closely correlated with changes in VAT but not with changes in SAT. SI and AIR were unchanged in the diet group but were improved in the voglibose and glyburide groups. CONCLUSIONS: In Japanese patients with newly diagnosed type 2 diabetes who were relatively lean but had excess VAT, diet with or without voglibose or glyburide effectively reduced VAT. Decrease in VAT was closely associated with improvement of glycemic control with diet. Additional use of voglibose or low-dose glyburide had no detrimental effects on abdominal adiposity and had beneficial effects on SI and AIR.

Abdomen↗