Establishment of Myocardial Strain Measurement Data in Pediatric Patients Without Structural Heart Disease: A Single Center Study.

Accurate assessment of LV systolic function remains a challenge, especially in the pediatric population. Myocardial strain measurement by 2D speckle tracking echocardiography (2DSTE) is a relatively new modality for assessment of regional and global myocardial wall motion. This study aims to establish the normative value among various pediatric age groups at a large pediatric tertiary care institution and to describe the challenges encountered in establishing such strain data. Transthoracic echocardiograms were acquired in 121 healthy children (age 0-21 years) and were retrospectively analyzed. The global longitudinal strain (GLS) was obtained by 2D speckle tracking using Philips Epiq7® and QLAB post processing software. The normative value for left ventricular GLS (%) obtained in our study was - 20.8 ± 2.3 (< 1 year); - 21.4 ± 2.2 (1-4 years); - 19.6 ± 2.4 (5-9 years); - 19.4 ± 2.6 (10-14 years); - 18.9 ± 3.0 (15-21 years). There was a statistically significant difference in GLS between the different age groups. The BMI (kg/m2) of assessed subjects were 14.6 ± 2.3 (< 1 year); 16.3 ± 1.5 (1-4 years); 16.7 ± 2.3 (5-9 years); 21.3 ± 4.6 (10-14 years); 23.9 ± 5.9 (15-21 years). There was no significant difference in GLS by gender or by BMI found in our study. We present our experience with establishment of normative values of 2DSTE in our pediatric echocardiography lab. This study shows that age is the major determinant of variation in peak GLS in healthy subjects, emphasizing the importance of establishment of normative data among various age groups in pediatrics.

Ethanol vapor self-administration in adult C57BL/6J male mice.

To determine if ethanol vapor is reinforcing, chambers with two nose-poke devices were used. First, C57BL/6J mice were trained to nose-poke at one (FR port) and then to hold a nose-poke for at least 1 s at the second (reward port) for 10% sucrose reinforcement. When mice held reward port nose-pokes for > or = 1 s on 95% of session trials, ethanol vapor (0.05%, w/v) or clean air replaced sucrose. In experiment 1, the FR requirement at the FR port was incremented from 1 to 8. Ethanol vapor (n=3) or clean air (n=3) was delivered for 1 s following a single nose-poke at the reward port after completing response requirements at the FR port. Nose-pokes at the FR port increased with increasing FR to maintain ethanol vapor intake, while clean air intake and its associated responding extinguished. In experiment 2, mice (n=4) controlled the duration of ethanol vapor delivery by providing vapor for as long as the mouse held a single poke in the reward port after completing response requirements at the FR port. Nose-pokes at the FR port increased with increasing FR to maintain ethanol vapor intake at the reward port. These findings indicate that ethanol vapor is reinforcing in adult C57BL/6J male mice.

Influence of cocaine self-administration on learning related to prefrontal cortex or hippocampus functioning in rats.

RATIONALE: Individuals who abuse cocaine have cognitive deficits, particularly in functions associated with the orbitofrontal cortex. It is not clear to what extent the impact of cocaine on cognitive functioning is related to its role as a behavioral reinforcer. A preclinical means to investigate this issue is to use a yoked-triad procedure in which sets of three animals either contingently self-administer cocaine or receive passive administration of cocaine or saline in a noncontingent manner. OBJECTIVE: Using this procedure, we assessed cocaine's effect on learning that requires a functionally intact prefrontal cortex (prelimbic or insular/orbital subregions) or hippocampus. METHODS: Rats self-administering 1-mg/kg unit doses of cocaine responded under a fixed-ratio 5, time-out 20-s schedule of drug delivery. Testing took place in a radial-arm maze within the first 30 min after 2-hr drug sessions ended, beginning after 2.5 months of cocaine or saline exposure. RESULTS: Rats self-administering cocaine earned 14-18 infusions on average throughout different phases of the study. In groupwise comparisons, learning in the visually guided delayed win-shift (prelimbic prefrontal cortex-related) and win-shift (hippocampus-related) tasks was not influenced by contingent or noncontingent cocaine exposure. Session latency, though, was shorter in both cocaine-exposed groups during the win-shift task. During the odor-guided delayed win-shift task (insular/orbital prefrontal cortex-related), learning was disrupted in rats self-administering cocaine, with no influence of noncontingent cocaine exposure. CONCLUSIONS: Based on these and previous findings, learning related to functioning of the insular/orbital prefrontal cortex and amygdala is the most consistently disrupted in cocaine-intoxicated rats after long-term drug exposure.