Intestinal morphometry and bile acid-induced mucosal injury in chronic experimental renal failure

To examine whether the intestinal mucosa in uremia is more prone to injury, we studied acute intestinal mucosal injury in rats with experimental chronic renal failure (RF) and sham-operated and starved control animals. Intestinal injury was produced by perfusing intestinal segments in vivo with 5 mmol/L chenodeoxycholic acid. Histologic specimens were then taken from the proximal and distal perfused and unperfused intestinal segments. Quantitative morphometry was done with computerized image analysis, and samples of the unperfused intestine were assayed for protein and DNA content. Chronic RF did not significantly affect the functional or morphologic injury caused by chenodeoxycholic acid. However, it was noted that RF rats had consistently taller villi and deeper crypts in all the samples studied. The protein content and the ratio of DNA to protein was similar among the three groups. The mechanism of the increase in villus height and crypt depth in the RF rats was not related to increases in tissue water content or to alterations in protein or DNA content, and the mechanism thus remains unexplained. This study clearly demonstrates, however, that the intestinal mucosa of rats with chronic renal insufficiency is not more susceptible to mucosal injury by bile acids than is the mucosa of appropriate control animals.

Effects of concentration of local anaesthetic drugs in extradural block

An increase in the concentration of bupivacaine from 0.5% to 0.75% and etidocaine from 1.0% to 1.5% for extradural block resulted in a more rapid onset of sensory analgesia and motor blockade, a greater frequency of adequate analgesia,a greater depth of motor block and a longer duration of sensory analgesia and motor blockade. An increase in the concentration of prilocaine from 2% to 3% failed to reveal any significant advantage. The use of the more concentrated solutions of bupivacaine and etidocaine would appear to afford significant clinical advantages in extradural anaesthesia for surgery.

Rapid determination of minimum inhibitory concentrations of antimicrobial agents by regression analysis of light scattering data

A novel, rapid, automated method for determining the minimum inhibitory concentrations of antimicrobial drugs within ranges acceptable for therapeutic application is described and validated in this report. By employing a simple modification of the Autobac photometer currently in use and in optically clear, modified Mueller-Hinton broth, the method utilizes forward light scattering data measured in the presence of two concentrations of the antimicrobial agent to compute the minimum inhibitory concentrations. Empirically derived regression equations which simultaneously use scattering data from two drug concentrations are employed in this computation, rather than simple breakpoint analysis in which the light scattering measured in the presence of each drug concentration is referred to a threshold level. The minimum inhibitory concentrations obtained with this new method were highly reproducible and, as shown by side by side comparisons were in excellent agreement with the minimum inhibitory cencentrations obtained with the International Collaborative Study broth dilution method.