Two- and three-dimensional transthoracic echocardiographic assessment of superior vena cava, crista terminalis, and right atrial appendage using the right parasternal approach.

BACKGROUND: The noninvasive assessment of superior vena cava (SVC), crista terminalis (CT), and the right atrial appendage (RAA) has clinical implications in determining the right atrium (RA) pressure in adult patients in whom the inferior vena cava cannot be imaged, in planning electrophysiological procedures and for evaluation of thrombi in RA/RAA. It is difficult to image these structures using standard two-dimensional transthoracic echocardiography (2DTTE), but the right parasternal approach has shown promise in the very few studies published so far. AIM: The aim of this study was to show the feasibility of this approach and its usefulness in qualitative and quantitative assessments of these structures by both 2D and three (3D) TTE in patients with and without known cardiac pathologies. MATERIAL AND METHODS: The study consisted of 38 adult patients, 17 of whom had cardiac pathologies (Group 1) while the remainder (Group 2) had no evidence of heart disease clinically or by echocardiography. RESULTS AND CONCLUSION: Both SVC and RAA could be imaged by 2DTTE and 3DTTE in 53% of 40 patients (two separate groups of 20 consecutive patients) studied demonstrating the technical feasibility of this approach. SVC size and collapsibility, CT and RAA size, and RAA fractional shortening were evaluated in both groups by both 2D and 3DTTE. 3DTTE provided incremental value over 2DTTE by its ability to view en face the SVC in short axis and the base of RAA and RAA volumes resulting in more comprehensive assessment of their size and function.

The mGluR5 antagonist fenobam induces analgesic conditioned place preference in mice with spared nerve injury.

Antagonists of metabotropic glutamate receptors (mGluRs) have the potential to act as analgesic drugs that may help alleviate chronic pain. This study was done to look at the possible rewarding properties of the mGluR5 antagonist, fenobam, in a cognitive assay. Analgesic conditioned place preference (aCPP) was used to examine the effects of fenobam (30 mg/kg) and the prototypical mGluR5 antagonist, MPEP, and these effects were compared to those of a drug with known analgesic properties, morphine (10 mg/kg). In each experiment, one group of mice received spared nerve injury (SNI) surgery to model chronic pain; the other group received a control sham surgery. Both fenobam and MPEP induced preference in the SNI mice, such that SNI mice spent significantly more time in the mGluR5 antagonist-paired chamber compared to a vehicle-paired chamber. No such preference developed for sham mice. Morphine induced preference in male and female mice in both the SNI and sham groups. The results showed that fenobam and MPEP likely reduced on-going distress in the SNI mice, causing them to prefer the chamber paired with the drug compared to the vehicle-paired chamber. Since sham animals did not prefer the drug-paired chamber, these data demonstrate that mGluR5 antagonism is non-rewarding in the absence of pain-like injury.