Fast measurements of average flow velocity by Low-Field ¹H NMR

In this paper, we describe a method for measuring the average flow velocity of a sample by means of Nuclear Magnetic Resonance. This method is based on the Carr-Purcell-Meiboom-Gill (CPMG) sequence and does not require the application of any additional static or pulsed magnetic field gradients to the background magnetic field. The technique is based on analyzing the early-time behavior of the echo amplitudes of the CPMG sequence. Measurements of average flow velocity of water are presented. The experimental results show a linear relationship between the slope/y-intercept ratio of a linear fit of the first echoes in the CPMG sequence, and the average flow velocity of the flowing fluid. The proposed method can be implemented in low-cost Low-Field NMR spectrometers allowing a continuous monitoring of the average velocity of a fluid in almost real-time, even if the flow velocity changes rapidly.

Alteration of the renal regulatory hormonal pattern during experimental obstructive jaundice

OBJECTIVE

The alteration of hormones regulating sodium and water status is related to renal failure in obstructive jaundice (OJ).

EXPERIMENTAL DESIGN

OJ was induced by common bile duct ligation. Samples were obtained from the control (SO) and OJ groups at 24 and 72 hours, and at 7 days. Different parameters related to biliary obstruction, liver and renal injury, and vasoactive mediators such as renin, aldosterone, endothelin-1 (ET-1) and prostaglandin E2 (PGE2) were studied.

RESULTS

Bile duct ligation caused an increase in total bilirubin (p < 0.001) and alkaline phosphatase (AP) (p < 0.001). The SO and OJ groups had the same values for diuresis, renin, and creatinine clearance at 24 h. However, animals with OJ had a lower sodium concentration in urine than SO animals (p < 0.01), as well as an increase in aldosterone levels (p < 0.03). ANP levels were moderately increased during OJ but did not reach statistical significance when compared to the SO group. In contrast, OJ animals showed a rise in serum ET-1 concentration (p < 0.001) and increased PGE2 in urine (p < 0.001).

CONCLUSIONS

Biliary obstruction induced an increase in ET-1 release and PGE2 urine excretion. These hormones might play a role during the renal complications associated with renal disturbances that occur during OJ.

Effect of red wine on oxidative stress and hypercholesterolemia induced by feeding a high-cholesterol diet in rat

The effect of red wine on oxidative stress and hypercholesterolemia induced by feeding a high-cholesterol diet (supplemented with 1.65% of cholesterol (w/w) for 4 weeks) to female Wistar rats was examined. When red wine was simultaneously supplemented to high-cholesterol diet, total cholesterol, triglycerides, atherogenic index and lipid peroxidation products significantly decreased compared with the high-cholesterol diet alone, while GSH content and antioxidative enzymes activities were enhanced. In the hypercholesterolemic rat the excretion of fecal bile acids, as well as their plasma and hepatic concentrations were increased significantly. Administration of red wine enhanced these values, indicating an increase in the cholesterol degradation. These results suggest that red wine may have a protective effect against oxidative stress, hypercholesterolemia and atherogenic index induced by high-cholesterol diet.