Outcomes of transcutaneous nerve stimulation for migraine headaches: a systematic review and meta-analysis

Journal of Neurology - Implanted and transcutaneous nerve stimulators have shown promise as novel non-pharmacologic treatment for episodic and chronic migraines. The purpose of this study was to...     

Interlaced x-ray microplanar beams: a radiosurgery approach with clinical potential

Studies have shown that x-rays delivered as arrays of parallel microplanar beams (microbeams), 25- to 90-microm thick and spaced 100-300 microm on-center, respectively, spare normal tissues including the central nervous system (CNS) and preferentially damage tumors. However, such thin microbeams can only be produced by synchrotron sources and have other practical limitations to clinical implementation. To approach this problem, we first studied CNS tolerance to much thicker beams. Three of four rats whose spinal cords were exposed transaxially to four 400-Gy, 0.68-mm microbeams, spaced 4 mm, and all four rats irradiated to their brains with large, 170-Gy arrays of such beams spaced 1.36 mm, all observed for 7 months, showed no paralysis or behavioral changes. We then used an interlacing geometry in which two such arrays at a 90-degree angle produced the equivalent of a contiguous beam in the target volume only. By using this approach, we produced 90-, 120-, and 150-Gy 3.4 x 3.4 x 3.4 mm(3) exposures in the rat brain. MRIs performed 6 months later revealed focal damage within the target volume at the 120- and 150-Gy doses but no apparent damage elsewhere at 120 Gy. Monte Carlo calculations indicated a 30-microm dose falloff (80-20%) at the edge of the target, which is much less than the 2- to 5-mm value for conventional radiotherapy and radiosurgery. These findings strongly suggest potential application of interlaced microbeams to treat tumors or to ablate nontumorous abnormalities with minimal damage to surrounding normal tissue.     

One-Anastomosis Gastric Bypass Revision for Gastroesophageal Reflux Disease: Long Versus Short Biliopancreatic Limb Roux-en-Y Gastric Bypass

Purpose

One-anastomosis gastric bypass (OAGB) may be associated with refractory gastroesophageal reflux disease (GERD). The nature of this GERD remains unclear. This complication can be treated either with an additional enteroenterostomy without shortening of gastric pouch (long biliopancreatic limb Roux-en-Y gastric bypass (L-BPL-RYGB)) or revision to conventional short biliopancreatic limb Roux-en-Y gastric bypass (S-BPL-RYGB). The objective of this study is to compare the aforementioned procedures in terms of efficacy on GERD symptoms.

Materials and Methods

Retrospective analysis between October 2012 and June 2020.

Results

Fifty-two patients underwent OAGB revision to S-BPL-RYGB (n = 21) or L-BPL-RYGB (n = 31) secondary to GERD. Investigation with pH impedance prior to revision was performed in 15 patients showing biliary reflux (BR) in 7 (46.6%), acid reflux (AR) in 6 (40%), and no confirmation in 2. Patients with AR had a revision to S-BPL-RYGB, whereas patients with BR underwent L-BPL-RYGB. Among the patients without pH metry results (n = 37), S-BPL-RYGB was performed for associated disabling digestive disorders or nutritional deficiencies. GERD was treated in 68% of patients with L-BPL-RYGB versus 95% of patients after S-BPL-RYGB. Patients, whose decision for revisional procedure was based on the results of pH impedance testing, did not reveal refractory GERD.

Conclusion

L-BPL-RYGB seems appropriate in patients with BR, whereas conversion to S-BPL-RYGB should be preferred if AR is present.

Graphical Abstract

     

A more unified picture for the thermodynamics of nucleic acid duplex melting: A characterization by calorimetric and volumetric techniques

We use a combination of calorimetric and volumetric techniques to detect and to characterize the thermodynamic changes that accompany helix-to-coil transitions for five polymeric nucleic acid duplexes. Our calorimetric measurements reveal that melting of the duplexes is accompanied by positive changes in heat capacity (DeltaCP) of similar magnitude, with an average DeltaCP value of 64.6 +/- 21.4 cal deg-1 mol-1. When this heat capacity value is used to compare significantly different transition enthalpies (DeltaHo) at a common reference temperature, Tref, we find DeltaHTref for duplex melting to be far less dependent on duplex type, base composition, or base sequence than previously believed on the basis of the conventional assumption of a near-zero value for DeltaCP. Similarly, our densimetric and acoustic measurements reveal that, at a given temperature, all the AT- and AU-containing duplexes studied here melt with nearly the same volume and compressibility changes. In the aggregate, our results, in conjunction with literature data, suggest a more unified picture for the thermodynamics of nucleic acid duplex melting. Specifically, when compared at a common temperature, the apparent large differences present in the literature for the transition enthalpies of different duplexes become much more compressed, and the melting of all-AT- and all-AU-containing duplexes exhibits similar volume and compressibility changes despite differences in sequence and conformation. Thus, insofar as thermodynamic properties are concerned, when comparing duplexes, the temperature under consideration is as important as, if not more important than, the duplex type, the base composition, or the base sequence. This general behavior has significant implications for our basic understanding of the forces that stabilize nucleic acid duplexes. This behavior also is of practical significance in connection with the use of thermodynamic databases for designing probes and for assessing the affinity and specificity associated with hybridization-based protocols used in a wide range of sequencing, diagnostic, and therapeutic applications.     

Neuromuscular organization of the Ctenophore Pleurobrachia bachei

Ctenophores are descendants of one of the earliest branching metazoan lineage with enigmatic nervous systems. The lack of convenient neurogenic molecules and neurotransmitters suggests an extensive parallel evolution and independent origins of neurons and synapses. However, the field lags due to the lack of microanatomical data about the neuro-muscular systems in this group of animals. Here, using immunohistochemistry and scanning electron microscopy, we describe the organization of both muscular and nervous systems in the sea gooseberry, Pleurobrachia bachei, from North Pacific. The diffuse neural system of Pleurobrachia consists of two subsystems: the subepithelial neural network and the mesogleal net with about 5,000–7,000 neurons combined. Our data revealed the unexpected complexity of neuromuscular organization in this basal metazoan lineage. The anatomical diversity of cell types includes at least nine broad categories of neurons, five families of surface receptors and more than two dozen types of muscle cells as well as regional concentrations of neuronal elements to support ctenophore feeding, complex swimming, escape, and prey capture behaviors. In summary, we recognize more than 80 total morphological cell types. Thus, in terms of cell-type specification and diversity, ctenophores significantly exceed what we currently know about other prebilaterian groups (placozoan, sponges, and cnidarians), and some basal bilaterians.     

Detection of β-Herpesviruses in Polish Adult Cord Blood Stem Cell Recipients by Real-Time PCR: Single Centre Study

Umbilical cord blood transplantation (UCBT) is known to be associated with increased risk of infections, compared to bone marrow or peripheral blood stem cell transplantation. In viral diseases for which specific treatment is available, real-time PCR assays are reliable diagnostic tools for timely initiation of appropriate therapy and for rapid assessment of the efficacy of antiviral treatment strategies. A retrospective review of samples from a group of seven adult cord blood stem cell recipients was made. Serum samples taken up to 180 days after transplantation were examined with quantitative real-time PCR for measurement of viral load (CMV, HHV-6, and HHV-7). Cytomegalovirus (CMV) DNA was detected in samples taken from four patients (57%) in the period of 20–80 days after transplantation. Products of amplification of human herpesvirus 6 (HHV-6) DNA were found in samples taken between days 25 and 37 following UCBT from only one patient (14%). On the other hand, the majority of patients (n = 6, 86%) had HHV-7 DNA detected in the period 15–58 days after transplantation. Co-infection with HHV-7 was demonstrated at onset of all episodes of microbiologically confirmed CMV or HHV-6 infection. Our observations indicate that real-time PCR is not only useful for monitoring herpesviral infections in transplant recipients, but is also a powerful method for clarifying the relationships between the viral load and clinical symptoms. Further investigation with a much larger group of patients will be needed to confirm these observations and translate them into a clinical approach.     

Neural mechanisms underlying co-activation of functionally antagonistic motoneurons during a Clione feeding behavior

The ability of some neural networks to produce multiple motor patterns required during different behaviors is a well-documented phenomenon. We describe here a dramatic transition from coordinated inhibition between two functionally antagonistic groups of motoneurons to their co-activation in the feeding neural network of the predatory mollusk Clione limacina. To seize its prey, Clione uses specialized oral appendages, called buccal cones, which are controlled by two groups of motoneurons: cerebral A (Cr-A) neurons controlling buccal cone protraction and cerebral B (Cr-B) neurons controlling buccal cone retraction. When Cr-A neurons are active, Cr-B neurons usually receive strong inhibitory inputs that terminate their firing, which leads to the full protraction and elongation of the buccal cones. We have found, however, that the Cr-A and Cr-B motoneurons sometimes burst simultaneously without any traces of inhibition in the Cr-B motoneurons. This transformation of the neural network activity from inhibitory interactions to co-activation presumably occurs during the late "extraction" period of the feeding behavior when buccal cones become partially retracted and rhythmically active. The transition from the inhibitory interaction to co-activation is controlled by the activity of a single pair of cerebral interneurons (Cr-Aint interneurons), which are electrically coupled to the Cr-A neurons and monosynaptically inhibit Cr-B neurons. Normally, the Cr-Aint interneurons are active along with Cr-A motoneurons and inhibit Cr-B motoneurons. During a period of co-activation, however, these interneurons do not produce spikes, thus allowing Cr-A motoneuron activation without inhibition of the Cr-B motoneurons.