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Biomedical subjects

A Itabashi

Publications and source records attributed to A Itabashi.

8 recordsLinked to original sources
PubMed1991

Effect of alpha 1-blockade on diminished forearm blood flow in diabetics.

An increased risk of atherosclerotic disease has been reported in patients with diabetes mellitus. The present study was therefore designed to determine forearm blood flow (FBF) in patients with essential hypertension or those with diabetes mellitus with or without hypertension. FBF determined by venous occlusion plethysmography decreased with age in controls as well as in patients with essential hypertension, whereas FBF in diabetics was significantly lower irrespective of age or blood pressure. As a result, vascular resistance was significantly higher in diabetics than in controls or patients with essential hypertension. Glycemic control in normotensive diabetics during 3 weeks significantly augmented a diminished FBF. alpha 1-Blockade by oral administration of 1 mg of prazosin also augmented the diminished FBF in diabetics, in association with a significant decrease in mean blood pressure and vascular resistance. These results suggest that FBF may be a simple and useful index for determining arterial and/or venous distensibility, and that alpha 1-blocker therapy, in addition to glycemic control, may be a first-line antihypertensive treatment for diabetics with associated hypertension.

Administration, Oral↗
PubMed1991

Effect of dietary calcium on serum BGP (osteocalcin).

The present study was designed to clarify the effects of dietary calcium (Ca) intake on serum BGP (osteocalcin) levels. Twelve women with a mean age of 21.2 years participated in the study. After one week of normal Ca intake (mean +/- SE, 535 +/- 2 mg/day), a low-Ca diet (163 +/- 1 mg/day) was given for one further week. Additional asparagine Ca (3 g as Ca/day) was also given to half of the subjects. Serum total and ionized Ca concentrations as well as BGP, PTH and 1,25(OH)2D3 were measured at the end of each period. Amounts of Ca and hydroxyproline excreted in urine were also determined. The plasma level of ionized Ca was significantly increased without any change in total Ca in either group. Low and high Ca intake decreased and increased urinary Ca excretion by 28% and 56%, respectively. Serum levels of BGP and 1,25(OH)2D3 were significantly augmented along with a transient increase in urinary hydroxyproline excretion after Ca deprivation. These results suggest that serum BGP is increased after one week of Ca restriction in healthy subjects.

Adult↗
PubMed1991

Salmon calcitonin induces pituitary tumor in rats.

Calcitonin is widely used in the treatment of post-menopausal osteoporosis. The present study was designed to investigate the effects of salmon calcitonin (SCT) on the incidence of the pituitary tumors in Sprague-Dawley (SD) rats. Subcutaneous injections of SCT at a dose of 160 IU/kg/day for 6 months reduced body weight and induced one pituitary hyperplasia and three pituitary adenomas in 4 of 5 animals, while 5 controls did not show any changes. Prolactin-positive cells were located at the periphery of the affected pituitaries adjacent to the prolactin-negative adenomas. In addition, serum concentrations of prolactin and TSH were lower than in the controls, although serum calcium or LH levels were not significantly different from the controls. Among 7 animals treated with SCT for 6 months followed by no medication for another 6 months, 5 adenomas were detected, one of which had invasive growth toward the adjacent tissue, whereas only one adenoma was found in 9 controls. These results suggest that SCT administration at a high dose may induce the formation of pituitary adenoma, or may accelerate the development of spontaneous pituitary adenomas, some of which show frequent mitotic figures and invasive growth into the surrounding tissue, possibly resulting in malignant transformation. This indicates the need for caution in considering whether calcitonin injections into patients with osteoporosis as well as Paget's disease may induce such pituitary tumors.

Adenoma↗
PubMed1991

Blood ketone bodies in NIDDM: relationship with diabetic control and endogenous insulin secretion.

To evaluate the relationship of blood ketone bodies with diabetic control and endogenous insulin secretion, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), fasting serum C-peptide (CPR), blood total ketone-bodies (TKB), blood acetoacetate (AcAc) and blood 3-hydroxybutyrate (3-OHB) were compared in 78 outpatients with non-insulin-dependent diabetes mellitus (NIDDM) treated with diet (n = 13), sulfonylurea (n = 52) and insulin (n = 13). TKB, AcAc and 3-OHB in patients treated with insulin were significantly higher than in patients treated with diet or sulfonylurea. In patients given diet therapy, log 3-OHB showed significant negative correlations with FPG, HbA1c and CPR. In patients treated with sulfonylurea, log 3-OHB showed significant positive correlations with FPG and HbA1c, but not with CPR. In patients treated with insulin, there were no correlations of log 3-OHB with FPG, HbA1c and CPR. For evaluation of the metabolic state in diabetes mellitus, measurement of blood ketone bodies is useful, and moreover necessary, in addition to diabetic control or determination of the endogenous insulin level.

3-Hydroxybutyric Acid↗
PubMed1990

Hyperreninemia due to increased renal renin synthesis in BioBreeding Worcester rats.

It is well known that diabetes mellitus is often associated with hypertension. We previously reported the unresponsiveness of renin release to volume depletion with impaired renal prostaglandin E2 synthesis in rats with streptozotocin-induced diabetes. However, we have found that BioBreeding Worcester rats, spontaneously susceptible to diabetes mellitus either before or after the onset of diabetes, showed a pronounced fourfold to ninefold increase in plasma renin activity in comparison with control Wistar rats. Furthermore, these rats developed mild hypertension as high as 134 mm Hg after the age of 90 days. The hyperreninemia responded to 1-week sodium loading or restriction; the blood pressure increased during sodium loading. Oral administration of captopril (30 mg/kg) for 1 week resulted in a large blood pressure decrease (-47.1 +/- 5.9 mm Hg, n = 10) in comparison with controls (-17.0 +/- 4.7 mm Hg, n = 12). Vascular response to angiotensin II was also attenuated. Plasma angiotensin II levels were 5.7-fold higher and associated with a 1.5-fold increase of plasma aldosterone concentration compared with control rats, whereas angiotensinogen-plasma concentrations were lower than in control rats. The renal renin content determined enzymatically or histochemically was more enhanced in BioBreeding Worcester rats than in control rats, but the renal renin messenger RNA levels did not differ. These results suggest that the strain-specific hyperreninemia in BioBreeding Worcester rats might be due to posttranscriptional abnormalities of renal renin synthesis. Further work is needed to elucidate the specific mechanism or mechanisms responsible.

Angiotensin II↗
PubMedDate not supplied

High glucose concentration suppresses mesangial laminin B2 gene expression.

To study the role of laminin in the rat mesangial cell attachment, cell adhesion to laminin-coated dishes was assayed by adding various amounts of a pentapeptide (YIGSR). YIGSR (20-100 micrograms/mL) inhibited the cell attachment to laminin-coated dishes. Mesangial laminin B2 messenger RNA (mRNA) levels were attenuated during exposure to 30 mM glucose or high osmolarity achieved by the addition of 25 mM choline chloride to 5 mM glucose (310 mOsm/kg H2O) for 3 hours. These results suggest that laminin, which may have a physiologic role in mesangial cell attachment, is produced in mesangial cells, and that the decrease of laminin B2 mRNA during hyperglycemia or exposure to high osmolarity may have some pathophysiologic significance in the development of diabetic nephropathy.

Amino Acid Sequence↗