To estimate the effectiveness of pulsatility in end-organ microcirculation after cardiogenic shock, experimental studies using swine were done. Cardiogenic shock was produced in 14 pigs by ligating the left anterior descending branches so that mean aortic pressure dropped to 60% of the control value. After inducing shock, left atrial to ascending Ao bypass was initiated. A pneumatic pulsatile pump (Zeon Medical Inc, Tokyo, Japan) was used in seven pigs (Group P) and a centrifugal pump (BP-80, BioMedicus Inc, Minneapolis, MN) in seven (Group NP). In both groups, about half the usual cardiac output was supported for 3 hr, maintaining mean aortic pressure at approximately 100 mm Hg. The pulse pressure was 36.6 +/- 4.6 mm Hg in Group P, and 14.3 +/- 1.5 mm Hg in Group NP. Epicardial and endocardial regional flows recovered after assist in both groups. There were no significant differences between the two groups. However, liver tissue flow, renal cortex flow, and stomach mucous flow in Group P was significantly higher than those of Group NP after support (p < 0.05). In addition, arterial blood ketone ratio in Group P was 0.61 +/- 0.13 vs 0.39 +/- 0.06 in Group NP, a significant difference (p < 0.05). These results suggest that in uneven blood flow distribution of end organs after cardiogenic shock, pulsatility was effective in improving and maintaining function and microcirculation of end organs, preventing multiorgan failure.

Animals↗

PubMedDate not supplied

5-Hydroxytryptamine (5-HT)-induced depolarization in isolated abdominal vagus nerves in the rat: involvement of 5-HT3 and 5-HT4 receptors.

In this study, we developed an electrophysiological technique for the in vitro measurement of isolated abdominal vagus nerve depolarization in the rat. This technique was used to compare abdominal and cervical vagus nerve depolarization values. Both 5-HT and a selective 5-HT3 agonist, 2-CH3-5HT, caused a concentration-dependent depolarization in rat isolated abdominal vagus nerves in vitro. Isolated cervical vagus nerves also showed concentration-dependent depolarization, although the isolated cervical vagus nerve depolarization was approximately 60% of that of the isolated abdominal vagus nerves at similar concentration ranges of 5-HT and 2-CH3-5HT in vitro. In isolated abdominal vagus nerves, a selective 5-HT3 antagonist, granisetron, produced a concentration-dependent decrease, but reduced the maximal response of 5-HT-induced depolarization in vitro. In isolated abdominal vagus nerves, selective 5-HT4 antagonist, SB204070, produced parallel and concentration-dependent shifts to the right on the concentration-response curves to 5-HT in vitro. These findings suggest that this electrophysiological method for evaluating isolated abdominal vagus nerve depolarization is a useful technique for the estimation of 5-HT-induced depolarization.

Abdomen↗

PubMedDate not supplied

Neuroepithelial (colloid) cyst of the cerebellar vermis containing a xanthogranuloma.

A case of a neuroepithelial cyst of the cerebellar vermis is presented. The cyst contained a viscous fluid and a xanthogranulomatous nodule. The fluid showed high signal on T1- and low signal on T2-weighted MR images. The xanthogranuloma showed mixed intensities with partial contrast enhancement. The correlation of the cyst contents and MR signals is discussed.

Adult↗