Biomedical subjects

R Sakamaki

Publications and source records attributed to R Sakamaki.

3 recordsLinked to original sources

PubMed1996

Decrease of serum ascorbic acid concentrations in patients with diabetic macroangiopathy.

The relationship between serum ascorbic acid (AA) and diabetic macroangiopathy was studied. Fifty-six patients with noninsulin-dependent diabetes mellitus were examined, together with 20 healthy controls matched for age against the diabetes patients. Aortic pulse wave velocity (PWV) was taken as an index of the severity of atherosclerosis. The level of serum AA in diabetic patients was significantly lower than that of the controls. Among the diabetic groups, those with elevated PWV levels by age demonstrated a significant drop in AA. No significant differences were seen in the level of serum dehydroascorbic acid (DHAA) between patients and controls, nor were there any significant differences among patient groups. The concentration of serum AA was inversely related to the risk factors of atherosclerosis, such as body mass index, Apo B/ Apo A-I ratio, thiobarbituric acid-reactive substances (TBARS), and microalbumin in urine. It was inferred from these findings that the depletion of serum AA was apparent in diabetics with advanced atherosclerosis.

Adult↗

PubMed1994

Hyperlipidemia in streptozocin-diabetic hamsters as a model for human insulin-deficient diabetes: comparison to streptozocin-diabetic rats.

Characteristics of the lipoprotein profile and metabolism of triglyceride-rich lipoproteins in diabetic hamsters were investigated to assess their suitability as a model for human diabetic hyperlipidemia. Diabetes was induced in the hamsters by intraperitoneal injection of streptozocin (30 mg/kg) for 3 days and compared with the results in streptozocin-diabetic rats (50 mg/kg intravenously). Similar degrees of hyperglycemia and hypoinsulinemia were observed 8 to 10 days after the final streptozocin injection in both groups. Fasting plasma lipid concentrations were about 2.5 times greater in hamsters than in rats. Plasma cholesterol was principally associated with high-density lipoprotein (HDL) in both rodents, although the distribution in very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) was significantly greater in hamsters (44%) than in rats (13%). Diabetes increased the concentrations of triglyceride, cholesterol, and phospholipid 5.6- to 7.8-fold in hamsters, whereas it increased them only 1.3- to 1.6-fold in rats. Diabetic hamsters have a plasma lipoprotein profile similar to that of diabetic man, ie, triglyceride-rich lipoproteins are increased and HDL cholesterol is decreased. The concentration of HDL cholesterol was inversely correlated with the severity of hypertriglyceridemia (r = .76, P < .005). This combination of events does not occur in diabetic rats. Hamsters had a low level of apoprotein B-48-containing triglyceride-rich lipoproteins, although diabetes increased the estimated concentration by fourfold. In rats apoprotein B-48 is the predominant form, but diabetes did not alter the relative proportion of apoprotein B isoforms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Existence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols in lipoproteins from diabetic patients and normal subjects.

We report evidence for the presence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols (cholesterol 7-hydroperoxides, Ch 7 alpha-OOH and Ch 7 beta-OOH, respectively) in human plasma lipoproteins in vivo, which had been reported to be markers of aging in rat skin. A comparative study was carried out focusing on the detection of Ch 7-OOHs in plasma lipoproteins from diabetic patients whose plasma has been suggested to be under high oxidative stress. Blood samples were collected from healthy volunteers (control) and diabetics with and without hypercholesterolemia. Ch 7-OOHs were isolated from low and high density lipoproteins (LDL and HDL, respectively) in the plasma of these subjects, identified, and determined by high-performance liquid chromatography with a chemiluminescence detector. The percent detection of Ch 7-OOHs in LDL from diabetics without hypercholesterolemia was similar to that in the control group. However, it was significantly higher in diabetics with hypercholesterolemia than in those without hypercholesterolemia. The percent detection of Ch 7-OOHs in HDL from diabetics without hypercholesterolemia was higher than both that in LDL from the same group and that in HDL from the control group.

Adult↗