High-resolution manometry and impedance-pH/manometry: valuable tools in clinical and investigational esophagology

Both high-resolution manometry (HRM) and impedance-pH/manometry monitoring have established themselves as research tools and both are now emerging in the clinical arena. Solid-state HRM capable of simultaneously monitoring the entire pressure profile from the pharynx to the stomach along with pressure topography plotting represents an evolution in esophageal manometry. Two strengths of HRM with pressure topography plots compared with conventional manometric recordings are (1) accurately delineating and tracking the movement of functionally defined contractile elements of the esophagus and its sphincters, and (2) easily distinguishing between luminal pressurization attributable to spastic contractions and that resultant from a trapped bolus in a dysfunctional esophagus. Making these distinctions objectifies the identification of achalasia, distal esophageal spasm, functional obstruction, and subtypes thereof. Ambulatory intraluminal impedance pH monitoring has opened our eyes to the trafficking of much more than acid reflux through the esophageal lumen. It is clear that acid reflux as identified by a conventional pH electrode represents only a subset of reflux events with many more reflux episodes being composed of less acidic and gaseous mixtures. This has prompted many investigations into the genesis of refractory reflux symptoms. However, with both technologies, the challenge has been to make sense of the vastly expanded datasets. At the very least, HRM is a major technological tweak on conventional manometry, and impedance pH monitoring yields information above and beyond that gained from conventional pH monitoring studies. Ultimately, however, both technologies will be strengthened as outcome studies evaluating their utilization become available.     

Superficial vascular anatomy of the medial prefrontal cortex: an anatomical study

Background

Superficial vascular anatomy of the medial prefrontal cortex, which is exposed after craniotomy for the anterior interhemispheric approach, has received little attention in the anatomy literature. This study focuses on the precise vascular anatomy of the medial part of the prefrontal cortex and provides more detailed information for surgery.

Methods

Five adult cadaveric heads were used in this study. After a bifrontal craniotomy, the dura was opened and the superficial vascular structures of the medial prefrontal cortex were exposed in 10 hemispheres. The CS was used as a landmark, and the location and the course of the medial cortical vessels were recorded. The variations were noted and photographed.

Results

There are 4 major superficial veins and 3 arteries on the medial prefrontal cortex, which are important during the surgery. Anterior frontal vein, MFV, PFV, and frontopolar veins drain the superficial part of the medial prefrontal cortex to the SSS. The frontomarginal artery and cortical branches of the frontopolar and callosomarginal arteries supply this region. One great BV on each hemisphere poses risk during the opening of the dura of the prefrontal cortex. All of the veins drain to the SSS.

Conclusions

The surface of the medial prefrontal cortex has a rich and complex vascular network and represents the first obstacle for surgery. The upper part of the medial prefrontal cortex seems safer than the lower part; the CS is a reliable and crucial landmark in planning and performing surgery in this region.     

Continuous enriched environment improves learning and memory in adult NMRI mice through theta burst-related-LTP independent mechanisms but is not efficient in advanced aged animals

Introduction

Effects of 3-month continuous environmental enrichment (EE) on cognitive abilities and on theta burst-related synaptic plasticity of CA1 hippocampal neuronal networks have been assessed in 6- and 20-month old NMRI female mice.

Results

EE decreased anxiety-like behavior and improved learning and memory performances in adult but not in aged mice. Electrophysiological results in CA1 hippocampal slices showed that basal synaptic transmission was not affected by EE in adult mice whereas it was partially improved in aged animals, even though not sufficient to rescue the decrease related to aging. Besides, no effect of EE on N-methyl-d-aspartate receptor activation and theta-burst-induced long-term potentiation was found in adult or aged animals.

Discussion

These results indicate that continuous EE is able to improve cognitive abilities in adult NMRI female mice, that does not correlate with changes in theta burst-related synaptic plasticity within neuronal networks. In addition, the lack of effects in aged animals suggests the existence of a critical delay for the beneficial effects of EE on cognitive aging.     

Reduced serine racemase expression contributes to age-related deficits in hippocampal cognitive function

To gain insight into the contribution of d-serine to impaired cognitive aging, we compared the metabolic pathway and content of the amino acid as well as d-serine-dependent synaptic transmission and plasticity in the hippocampus of young and old rats of the Wistar and Lou/C/Jall strains. Wistar rats display cognitive impairments with aging that are not found in the latter strain, which is therefore considered a model of healthy aging. Both mRNA and protein levels of serine racemase, the d-serine synthesizing enzyme, were decreased in the hippocampus but not in the cerebral cortex or cerebellum of aged Wistar rats, whereas the expression of d-amino acid oxidase, which degrades the amino acid, was not affected. Consequently, hippocampal levels of endogenous d-serine were significantly lower. In contrast, serine racemase expression and d-serine levels were not altered in the hippocampus of aged Lou/C/Jall rats. Ex vivo electrophysiological recordings in hippocampal slices showed a marked reduction in N-methyl-d-aspartate-receptor (NMDA-R)-mediated synaptic potentials and theta-burst-induced long-term potentiation (LTP) in the CA1 area of aged Wistar rats, which were restored by exogenous d-serine. In contrast, NMDA-R activation, LTP induction and responses to d-serine were not altered in aged Lou/C/Jall rats.These results further strengthen the notion that the serine racemase-dependent pathway is a prime target of hippocampus-dependent cognitive deficits with aging. Understanding the processes that specifically affect serine racemase during aging could thus provide key insights into the treatment of memory deficits in the elderly.     

A novel intermittent mechanical compression device for stasis prevention in the lower limbs during limited mobility situations

INTRODUCTION: Intermittent pneumatic mechanical compression is commonly applied to obviate venous stasis in patients with increased risk of thromboembolism. Aviafit is a small battery-operated intermittent compression device using a patented mechanical, non-pneumatic technology. Our objective was to examine its ability to prevent venous stasis. MATERIALS AND METHODS: Doppler ultrasonography was used to determine venous hemodynamics of 22 healthy volunteers in both legs, before applying the Aviafit to one randomly selected leg, upon device activation and after 30 min. Each measurement provided values for peak flow velocity (PFV) and total volume flow (TVF). RESULTS: The PFV values were significantly higher in the treated leg upon activation of the Aviafit and at 30 min, compared to the baseline value and to the PFV of the untreated leg at the corresponding time points (p<0.001 for each). The TVF increased in the treated leg from baseline of 48 ml/min to 56 ml/min at T0, and then gradually decreased, similar to the untreated leg. At T30, 64% of the treated legs had a higher TVF than their untreated counterparts. CONCLUSIONS: The lightweight, battery-operated and user-friendly Aviafit can provide the same hemodynamic benefits as larger conventional intermittent pneumatic compression devices. Its potential advantages for prophylaxis of thromboembolism and increased compliance in rehabilitation and homecare, and for use during long periods of immobility such as during flights, are evident.