Application Of Ringer Solution Research Articles

Effects of hydroxyethyl starch and cell-free hemoglobin on microcirculation, tissue oxygenation, and survival in severe acute porcine pancreatitis: results of a randomized experimental trial.

Severe acute pancreatitis is a life-threatening disease with a high mortality; so far, no causal treatment is known. The aim of this study was to evaluate the therapeutic potential of hydroxyethyl starch (HES) and cell-free hemoglobin in an experimental model. Thirty-nine pigs were randomly assigned into 3 groups. Severe acute pancreatitis was induced by intraductal injection of glycodeoxycholic acid in combination with intravenous administration of cerulein. All animals were kept in isovolemic conditions by application of Ringer solution, 10% HES, or cell-free hemoglobin. The pancreatic microcirculation was evaluated over 8 hours. Thereafter, the animals were observed for 6 days followed by killing of the animals and histopathologic examination. The administration of HES and cell-free hemoglobin led to improved microcirculation and tissue oxygenation compared with the Ringer's group. Consequently, the histopathologic damage was reduced (5.5 [3-8.5] vs 9.5 [7.5-11]; P < 0.001). In addition, the mean survival was significantly longer at 121 hours (95% confidence interval, 102-139) versus the Ringer group's 57 hours (95% confidence interval, 32-82; P < 0.001). The administration of HES and cell-free hemoglobin can improve microcirculation in severe acute porcine pancreatitis, with consequent reduction in histopathologic damage and mortality. Therefore, this might represent an interesting therapeutic option in the treatment of severe acute pancreatitis.

Optical responses evoked by cerebellar surface stimulation in vivo using Neutral Red

The pH sensitive dye, Neutral Red, was used with optical imaging techniques to map intracellular pH shifts elicited by cortical surface stimulation of the rat cerebellum. In the in vivo rat cerebellar cortex stained with Neutral Red, a brief stimulus train (three stimuli at 33 Hz) evoked a longitudinal beam of increased fluorescence (acidic shift) running parallel to the long axis of the folium within 100 ms of stimulation onset. A 5–10 s stimulus train (5–20 Hz) produced a biphasic optical response consisting of a beam of increased fluorescence (acidic shift) which returned to baseline in approximately 60 s, followed by a beam of decreased fluorescence (alkaline shift) for up to 120 s. A close spatial correspondence was observed between electrophysiological and optical maps of the response to surface stimulation. Application of acetazolamide enhanced the optical signals, acetabenzolamide-phenoxyethene had no effect, and the glutamate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, decreased the optical signals. Increased fluorescence was produced by superfusion of the cerebellar cortex with acidic Ringer solutions and a decrease in fluorescence by basic solutions. These fluorescence changes also occurred in the presence of several ion channel/receptor blockers. Increased fluorescence resulted from superfusion with Ringer solution containing sodium propionate and decreased fluorescence with the transition from 5% carbon dioxide to nominally carbon dioxide-free Ringer solution. Recovery from acid loading with ammonium chloride was prevented by amiloride, an inhibitor of the Na +/H + transporter. Application of Ringer solution with high potassium concentration produced an increase in fluorescence but only a decrease in fluorescence was detected when neuronal blockers were present, an effect consistent with a glial contribution. This decrease in fluorescence was blocked by adding barium. No epifluorescent optical signals were obtained from unstained preparations or preparations stained with cell-permeant fluorescence markers, suggesting little contribution from activity-dependent volume changes and other intrinsic signals. These results demonstrate that the Neutral Red optical signals evoked by cerebellar surface stimulation are primarily pH based and include a significant component related to intracellular pH shifts. The large amplitudes of these optical signals are particularly useful for mapping neuronal activity. Furthermore, this technique provides a novel tool for the study of pH changes in vivo at both high spatial and temporal resolution.

Cochlear effects of locally applied inhibitors

The round window has been used as a route for introducing ototoxic substances into the inner car in order to bypass barriers between the systemic circulation and the inner car. We have used this method to locally administer sodium, potassium‐ATPase inhibitors and chloride transport inhibitors to the inner ear of the chinchilla. Drugs dissolved in Ringer solution were applied on the round window membrane. Endocochlear potential (EP) was recorded from the basal turn using the round window approach. The EP was not altered following application of Ringer solution as a control. Following application of ouabain (10 mM), the EP steadily declined. After vanadate (10 mM), the EP initially increased, and subsequently declined. Sanguinarine did not alter the EP. The loop diuretics furosemide and piretanide caused a marked decline in the EP after local application. However, the stilbene derivative DIDS did not alter the EP after topical application. These findings raise questions about whether the loop diuretics have any effect on chloride transport in the cochlea and makes it appear unlikely that active chloride transport contributes to the normal EP. [Work supported by NIH and Deafness Research Foundation.]