The oxygen tension (PO2) in the renal cortex and outer renal medulla in 26 rats was studied by use of oxygen microelectrodes before and after injection of x-ray contrast media (CM). The CM, iopromide, ioxaglate and iotrolan were administrated intravenously in iodine equivalent doses (1,600 mg iodine/kg body wt). Ringer's solution was used as the control. In the outer medulla, all three CM induced a decrease in PO2: iopromide (N = 6) from 30 +/- 3 to 18 +/- 4 mm Hg; ioxaglate (N = 7) from 32 +/- 6 to 15 +/- 4 mm Hg; and iotrolan (N = 6) from 36 +/- 3 to 14 +/- 4 mm Hg. All these decreases were significant. After the injection of Ringer's (N = 7) there was an increase from 34 +/- 3 to 35 +/- 3 mm Hg. In the cortex a slight decrease was noted for injection of CM, but this was significant only after injection of iotrolan. All tested contrast media decrease PO2 in the outer renal medulla, which may partly explain contrast medium-induced acute renal failure.

Hemodynamic factors may play a role in the development of acute renal failure following administration of contrast media (CM). In this study the effect of intravenous injection of contrast media and mannitol on red blood cell velocity (VRBC) and red blood cell aggregation in renal medullary vessels was studied in 58 rats. Renal medullary blood flow was investigated by a cross-correlation technique and by a visual aggregation score. The CM, namely diatrizoate, iopromide, iohexol, ioxaglate, iotrolan, were given in iodine equivalent doses (1600 mg/kg body wt). Mannitol (950 mOsm/liter) and Ringer's solution were used as controls. The same vessels were studied 30 minutes before and 30 minutes after injections. VRBC decreased significantly after injection of diatrizoate, iopromide, iohexol, iotrolan and mannitol. Ringer's solution and ioxaglate did not significantly alter medullary blood flow, while iotrolan and mannitol caused the largest decreases in VRBC. All CM and mannitol caused both red cell aggregation and cessation of blood flow. The decrease in blood flow and increase in red blood cell aggregation after injection of CM and mannitol may partly explain the occurrence of contrast medium-induced acute renal failure.

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Tortuosity of an artery can disturb fluid mechanics and cause flow separation, which might in turn promote atherogenesis. This study discusses theoretically several quantitative measures of arterial tortuosity and curvature in two dimensions and tests them with computations from digitized femoral arteriograms. When reproducibility, sensitivity to scaling and computational procedure, and agreement between the measures were all taken into account, the total curvature and distance factor were considered the most suitable measures. Significant correlations were found between tortuosity and atherosclerosis measures, but the interpretation of this finding is not straightforward.

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The aim of the Probucol Quantitative Regression Swedish Trial (PQRST) (n = 303) was to investigate whether probucol (0.5 g BID) added to diet and cholestyramine (8 g BID) could retard progression or induce regression of femoral atherosclerosis in hypercholesterolemic (> 6.86 mmol/L) subjects. Probucol did not induce regression over the 3-year trial period as estimated by change in lumen volume on quantitative arteriography of a 20-cm segment of the femoral artery. In this report we studied in a representative subgroup (n = 72) whether the reduction in HDL concentrations induced by probucol could explain the failure of the drug to be effective. We analyzed the effects of treatment on HDL particle size subclasses. Probucol lowered the relative level of HDL2b, comprising the largest HDL particles, by 53% and the protein concentration of HDL2b by 67%. The protein reduction in HDL was mainly confined to the apolipoprotein A-I moiety. The change in lumen volume correlated significantly with change in HDL, ie, HDL cholesterol (r = .34, P < .01), HDL2 cholesterol (r = .37, P < .01), HDL2b protein (r = .44, P < .001), and the relative HDL2b value (r = .51, P < .001). The corresponding values for relative HDL2b, distribution calculated on the active (n = 35) and placebo (n = 37) groups separately were also significant (r = .39 and .32, respectively; both P < .05). The correlation between drug-induced change in the relative HDL2b concentration and change in atherosclerosis was independent of the alteration in triglyceride concentration and could not be explained by treatment interaction.(ABSTRACT TRUNCATED AT 250 WORDS)

The PTB-suction prosthesis has been studied by a roentgenological technique. There is complete contact between the skin of the stump and the plastic inner surface of the socket. The movement of the stump in the socket is minimal. The displacement of the skeletal stump is reduced to half in the PTB-suction prosthesis, compared with the strap-suspended PTB prosthesis. As a result, the stability between stump and socket is increased, provided that the stump is sufficiently long. Skin sores are avoided. The prosthesis, when adequately fitted, guarantees a good circulation within the stump and a cosmetically favourable fit with a feeling of walking with "a normal leg".

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