Antidiabetic activity of white skinned sweet potato (Ipomoea batatas L.) in obese Zucker fatty rats.

Antidiabetic effects of white skinned sweet potato (Ipomoea batatas L.) (WSSP) and troglitazone, an insulin sensitizer, were investigated. Hyperinsulinemia in Zucker fatty rats was reduced by 23%, 26%, 60% and 50%, respectively, 3, 4, 6 and 8 weeks after starting the oral administration of WSSP. Similar results were obtained with troglitazone. In the glucose tolerance test after 7 weeks of treatment, increases in blood glucose levels after glucose loading were inhibited by the administration of WSSP. Glucose tolerance was also improved. Blood triacylglyceride (TG) and free fatty acid (FFA) lactate levels were lowered by the oral administration of WSSP. Similar effects on blood insulin, lipid and lactate levels were observed after the administration of troglitazone. Body weight gain increased in the troglitazone group, but not in the WSSP group, compared to the control group. In histological examinations of the pancreas of Zucker fatty rats, remarkable regranulation of pancreatic islet B-cells was observed in the WSSP and troglitazone groups after 8 weeks of treatment. These results suggest that WSSP shows remarkable antidiabetic activity and improves the abnormality of glucose and lipid metabolism by reducing insulin resistance.

Enhanced depressor effect of centrally administered high-calcium solution in salt-loaded experimental hypertension.

The depressor effect by oral calcium supplementation is known to be more pronounced in salt-dependent than in renin-dependent hypertension. This study was conducted to investigate the role of central calcium on two different pathophysiologic subtypes of experimental hypertension; (a) salt-dependent, deoxycorticosterone acetate-salt hypertensive rats (DOCA), and (b) renin-dependent, 2-kidney, 1 clip (2-K, 1C) hypertensive rats. In DOCA (n = 10), high-calcium solution (Ca+2, 65.2 mM, 10 microl) given centrally (i.c.v.) elicited a marked decrease in mean blood pressure (MBP; 170 +/- 4 to 138 +/- 5 mm Hg, p < 0.01) with a decrease in heart rate (HR; 390 +/- 18 to 344 +/- 17 beats/min, p < 0.05) lasting for 40 min. In 2-K, 1C (n = 10), high-Ca2+ i.c.v. showed a lesser decrease in MBP (178 +/- 4 to 171 +/- 5 mm Hg) and HR (419 +/- 10 to 395 +/- 12 beats/min) with shorter duration (for 20 min) than in DOCA. This significant depressor and bradycardic response to Ca2+ i.c.v. observed in DOCA was dose dependent at Ca2+ concentrations between 65.2 and 130.4 mM. In DOCA, high Ca2+ i.c.v. reduced the plasma noradrenaline (Nad) concentration significantly (479 +/- 81 to 319 +/- 62 pg/ml, p < 0.05). These results suggest that central Ca2+ plays a more important role in regulating sympathetic nerve activity and BP in salt-dependent than in renin-dependent experimental hypertension.

Double-contrast barium enema study with computed radiography: assessment in detection of colorectal polyps.

Feasibility and diagnostic performance of digital radiography in gastrointestinal imaging have not been fully investigated. We performed double-contrast barium enema study with computed radiography (CR-DCBE) on a routine basis, and the efficacy of this system for detection of colorectal polyps was investigated. The files of 76 patients, who had undergone both CR-DCBE and colonoscopy, were reviewed by two observers who were blinded to the colonoscopic findings. The radiation dose of CR-DCBE was reduced to 50% of conventional film-screen system. By using colonoscopic findings as a reference, the sensitivity and positive predictive value for colorectal polyps were 66% to 71% and 32% to 41%, respectively. There was no significant interobserver difference. The use of postprocessing with gray-scale reversal and edge enhancement did not significantly improve the results. The sensitivity for polyps smaller than 1 cm was comparable with published data of conventional film-screen systems. Our preliminary results show that CR-DCBE has an acceptable sensitivity for detection of colorectal polyps. It is suggested that the use of CR is a promising approach to digital gastrointestinal radiography.