Correlation of 10-milliliter digital subtraction ventriculograms compared with standard cineangiograms

Left ventriculograms were obtained with the use of 10 ml of contrast media by passing fluoroscopic video images through a video image processor. The low concentration of dye in the left ventricle was enhanced by the technique of mask mode subtraction, and the images were postprocessed to increase visibility by manipulation of the gray scale and contrast levels. These digital subtraction angiograms were compared to standard cineangiograms by means of 40 ml of contrast media. Of 30 patients studied, six (20%) had runs of ventricular tachycardia during the cineangiogram and had to be excluded. In the remaining 24 patients, there was a good correlation between the two techniques for left ventricular end-diastolic volume (r = 0.77, end-systolic volume (r = 0.95), and ejection fraction (r = 0.97). Spatial resolution in the digital studies was adequate to appreciate wall motion abnormalities that were visualized on the cineangiograms. Left ventricular end-diastolic pressure (LVEDP) did not change after the 10 ml injection, but the mean LVEDP rose 6.0 mm Hg after the 40 ml cineangiograms (p < 0.01). Digital subtraction angiography can be used to obtain left ventriculograms with one-fourth the amount of contrast media and one-fourth the x-ray exposure compared to standard cineangiograms. This technology will permit multiple left ventriculograms to be obtained which, in turn, will allow intervention studies to be performed in the catheterization laboratory.     

Antagonism of the dopamine D1‐like receptor in mesocorticolimbic nuclei attenuates acute food deprivation‐induced reinstatement of heroin seeking in rats

The neurotransmitter dopamine (DA) plays a critical role in both priming‐and cue‐induced reinstatement of extinguished drug‐seeking behavior, but its role in stress‐induced reinstatement is less clear. Our laboratory has recently demonstrated that systemic administration of the DA D1‐like receptor antagonist, SCH 23390, attenuates acute food deprivation (FD) stress‐induced reinstatement. The current study was designed to elucidate the brain regions critical to the effect of SCH 23390 on FD stress‐induced reinstatement. Rats were trained to press a lever to self‐administer heroin (0.1 mg/kg/inf) over a period of 10 days. Following training, heroin was removed leading to an extinction of lever pressing. Next, rats were tested for reinstatement twice, under extinction conditions: once following 21–48 h FD; and once under sated conditions. Prior to testing, SCH 23390 was administered into the nucleus accumbens (NAc) shell (0.0, 0.3, 0.6 μg/side), NAc core (0.0, 0.3, 0.6 μg/side), dorsomedial prefrontal cortex (dmPFC; 0.0, 0.2, 2.0 μg/side), ventromedial prefrontal cortex (vmPFC; 0.0, 2.0 μg/side) or basolateral amygdala (BLA; 0.0, 1.0, 2.0 μg/side). An attenuation of FD‐induced reinstatement of heroin seeking was seen in rats injected with SCH 23390 into the NAc shell, dmPFC or BLA, but not into the NAc core or the vmPFC. These findings support the hypothesis that DA transmission through the DA D1‐like receptors plays a critical role in stress‐induced reinstatement of heroin seeking.     

Effects of surgery for obstructive sleep apnea on cognitive function and driving performance

Background

Obstructive sleep apnea (OSA) is associated with a significantly increased risk of motor vehicle accidents in addition to such cognitive impairments as attention and memory deficits. The aim of the study was to examine the effect of upper airway surgery for OSA on driving and cognitive function.

Methods

Adult patients who underwent surgery for OSA at a tertiary medical center in 2016–2019 were prospectively recruited. Patients were assessed before and 3–6 months after surgery with a self-report and neurocognitive battery and a driving simulation platform.

Results

The cohort included 32 patients of average age 46.9 ± 11.6 years. During the 3 years before treatment, 9 patients had been involved in road accidents and 18 were detained by police for traffic violations. After surgery, there was a significant decrease in the Epworth Sleepiness Scale (13.7 vs. 8.1, p 0.043) and a significant reduction in time to completion of the Color Trail Test (part 1: 21.4 vs 18.7 s, p = 0.049; part 2: 46.8 vs 40.5 s, p = 0.038). Improvements in divided attention and selective attention response times were noted on the advanced stages of the Useful Field of Vision Scale (p = 0.013, p = 0.054). Before surgery, patients showed a high tendency to drive over the speed limit and to cross the dividing line to the opposite lane on the simulation test. Nevertheless, all considered themselves good drivers. These tendencies decreased after treatment.

Conclusions

Surgery for OSA can significantly improve driving performance and cognitive function.

     

Regeneration in denervated toad (bufo viridis) gastrocnemius muscle and the promotion of the process by low energy laser irradiation

Background: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of “invasive” and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles. Methods: Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm²) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone. Results: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 ± 4% and 6 plusmn; 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 plusmn; 2% and 11 plusmn; 2%, respectively) in the control muscles. The young myofibres populated 34 plusmn; 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 ± 2%) in control denervated muscles. Conclusions: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are “recruited” and participate in the process of regeneration. © 1995 Wiley-Liss, Inc.     

Teacher–student neural coupling during teaching and learning

Human communication is remarkably versatile, enabling teachers to share highly abstracted and novel information with their students. What neural processes enable such transfer of information across brains during naturalistic teaching and learning? Here, a teacher was scanned in functional magnetic resonance imaging while giving an oral lecture with slides on a scientific topic followed by a review lecture. Students were then scanned while watching either the intact Lecture and Review (N = 20) or a temporally scrambled version of the lecture (N = 20). Using intersubject correlation, we observed widespread Teacher–Student neural coupling spanning sensory cortex and language regions along the superior temporal sulcus as well as higher-level regions including posterior medial cortex (PMC), superior parietal lobule, and dorsolateral and dorsomedial prefrontal cortex. Teacher–student alignment in higher-level areas was not observed when learning was disrupted by temporally scrambling the lecture. Moreover, teacher–student coupling in PMC was significantly correlated with learning: the more closely the student’s brain mirrored the teacher’s brain, the more the student improved their learning score. Together, these results suggest that the alignment of neural responses between teacher and students may reflect effective communication of complex information across brains in classroom settings.