A novel GalR2-specific peptide agonist

The galanin peptide family and its three receptors have with compelling evidence been implicated in several high-order physiological disorders. The co-localization with other neuromodulators and the distinct up-regulation during and after pathological disturbances has drawn attention to this neuropeptide family. In the current study we present data on receptor binding and functional response for a novel galanin receptor type 2 (GalR2) selective chimeric peptide, M1145 [(RG)₂-N-galanin(2-13)-VL-(P)₃-(AL)₂-A-amide]. The M1145 peptide shows more than 90-fold higher affinity for GalR2 over GalR1 and a 76-fold higher affinity over GalR3. Furthermore, the peptide yields an agonistic effect in vitro, seen as an increase in inositol phosphate (IP) accumulation, both in the absence or the presence of galanin. The peptide design with a N-terminal extension of galanin(2-13), prevails new insights in the assembly of novel subtype specific ligands for the galanin receptor family and opens new possibilities to apply the galanin system as a putative drug target.     

A novel metalloprotease from Vipera lebetina venom induces human endothelial cell apoptosis.

A novel endothelial cell apoptosis inducing metalloprotease (VLAIP) was found in the snake venom of Vipera lebetina. This metalloprotease is a heterodimeric glycoprotein with molecular mass of about 106 kDa. The protease hydrolyzes azocasein, fibrinogen and oxidized insulin B-chain. The enzyme readily hydrolyzes the Aalpha-chain and more slowly Bbeta-chain of fibrinogen. VLAIP does not cleave fibrin. The complete amino acid sequences of the two different monomers of VLAIP are deduced from the nucleotide sequences of cDNAs encoding these proteins. The full-length cDNA sequences of the VLAIP-A and VLAIP-B encode open reading frames of 616 and 614 amino acids that include signal peptide, propeptide and mature metalloproteinase with disintegrin-like and cysteine-rich domains. VLAIP belongs to the metalloprotease/disintegrin family of reprolysins and has high identity with the proteins that induce apoptosis of endothelial cells. Treatment of HUVEC cells with VLAIP induces changes in the attachment of cells to the substrate and causes cell death. We demonstrated that VLAIP inhibits endothelial cell adhesion to extracellular matrix proteins: fibrinogen, fibronectin, vitronectin, collagen I, and collagen IV. The induction of apoptosis by VLAIP was shown by means of a typical DNA fragmentation pattern of apoptotic cells as well as by monitoring phosphatidylserine externalization using annexin V-FITC staining and flow cytometric analysis.     

Necklace‐embedded electrocardiogram for the detection and diagnosis of atrial fibrillation

BackgroundAtrial fibrillation (AF) is the major cause of stroke since approximately 25% of all strokes are of cardioembolic‐origin. The detection and diagnosis of AF are often challenging due to the asymptomatic and intermittent nature of AF.HypothesisA wearable electrocardiogram (ECG)‐device could increase the likelihood of AF detection. The aim of this study was to evaluate the feasibility and reliability of a novel, consumer‐grade, single‐lead ECG recording device (Necklace‐ECG) for screening, identifying and diagnosing of AF both by a cardiologist and automated AF‐detection algorithms.MethodsA thirty‐second ECG was recorded with the Necklace‐ECG device from two positions; between the palms (palm) and between the palm and the chest (chest). Simultaneously registered 3‐lead ECGs (Holter) served as a golden standard for the final rhythm diagnosis. Two cardiologists interpreted independently in a blinded fashion the Necklace‐ECG recordings from 145 patients (66 AF and 79 sinus rhythm, SR). In addition, the Necklace‐ECG recordings were analyzed with an automatic AF detection algorithm.ResultsTwo cardiologists diagnosed the correct rhythm of the interpretable Necklace‐ECG with a mean sensitivity of 97.2% and 99.1% (palm and chest, respectively) and specificity of 100% and 98.5%. The automatic arrhythmia algorithm detected the correct rhythm with a sensitivity of 94.7% and 98.3% (palm and chest) and specificity of 100% of the interpretable measurements.ConclusionsThe novel Necklace‐ECG device is able to detect AF with high sensitivity and specificity as evaluated both by cardiologists and an automated AF‐detection algorithm. Thus, the wearable Necklace‐ECG is a new, promising method for AF screening. Clinical trial registration: Study was registered in the ClinicalTrials.gov database ({"type":"clinical-trial","attrs":{"text":"NCT03753139","term_id":"NCT03753139"}}NCT03753139).     

Endoscopic sclerosis of the cardia affects gastroesophageal reflux

Summary Gastroesophageal reflux disease remains a disorder of unknown etiology associated with abnormal function of the lower esophageal sphincter (LES) and other physiological co-factors of the pathologic reflux. Effective operations for reflux are designed to reinforce the anti-reflux barrier and alter the tendency towards abnormal reflux. We have postulated that the most important component of these procedures is the prevention of distraction of the lowermost components of the LES at the onset of a potential reflux episode. Distraction of the LES causes shortening of the effective sphincter mechanism and can initiate experimental reflux events. In this study we used endoscopic sclerosis of the submucosal space at the cardia as a means of reducing distraction of the cardia in the hope that this would reduce abnormal reflux events. Canine gastroesophageal reflux was induced by intravenous atropine and monitored by continuous esophageal pH monitoring. Sclerosis of the cardia prevented gastroesophageal reflux, without measurable effect on the LES pressure or length. Endoscopic sclerosis of the cardia may be a useful technique in the control of human gastroesophageal reflux.Presented at the International Congress on Surgical Endoscopy, Ultrasound, and Interventional Techniques, Berlin 1988     

Effect of vitamin B6 vitamers on platelet aggregation

The vitamers of vitamin B₆ inhibit platelet aggregation. However, their effect is weak when used separately. After the supplementation of one vitamer, the concentrations of the other ones also increase in plasma due to the interconversion of vitamin B₆ forms. It can be suggested that different vitamers in blood can interact with each other. The aim of this work was to test the effect of different vitamer combinations on platelet aggregation in vitro. Platelet aggregation was induced by ADP, collagen or arachidonic acid and measured photometrically in a Chronolog aggregometer. The inhibition of platelet aggregation by the pairwise combinations of the vitamers was significantly stronger than that of each vitamer separately. The combinations of three and four vitamers were yet more effective, inhibiting platelet aggregation at the concentration of 4 μM. Possible involvement of inhibitory prostaglandins in the effect of vitamin B₆ was studied. The inhibition of platelet aggregation by the vitamers could be prevented by the antagonist of prostacyclin receptors, CAY10441 while the antagonist of prostaglandin D₂ receptors, MK 0524 was ineffective. The results suggest that vitamin B₆ vitamers cause a synergistic inhibitory effect on platelet aggregation at concentrations that can be mediated by the activation of prostacyclin receptors with prostaglandin E₁.     

Conjugation of adenosine and hexa-(D-arginine) leads to a nanomolar bisubstrate-analog inhibitor of basophilic protein kinases

Conjugates of oligoarginine peptides with adenine, adenosine, adenosine-5'-carboxylic acid, and 5-isoquinolinesulfonic acid were synthesized and characterized as bisubstrate-analog inhibitors of cAMP-dependent protein kinase. Adenosine and adenine derivatives were connected to the N- or C-terminus of peptides containing four to six L- or D-arginine residues via a linker with a length that had been optimized in structure-activity studies. The orientation of the peptide chain strongly affected the activity of compounds incorporating D-arginines. The biligand inhibitor containing Hidaka's H9 isoquinolinesulfonamide connected to the L-peptide had 65 times higher potency than the corresponding adenosine-containing conjugate, while both types of the conjugate comprising D-peptides had similar low nanomolar activity. Two of the most active adenosine- and H9-peptide conjugates were tested in the panel of 52 different kinases. At 1 microM concentration, both compounds showed strong (more than 95%) inhibition of several basophilic AGC kinases, including pharmaceutically important kinases ROCK II and PKB/Akt.     

Counting calories in Drosophila diet restriction

The extension of life span by diet restriction in Drosophila has been argued to occur without limiting calories. Here we directly measure the calories assimilated by flies when maintained on full- and restricted-diets. We find that caloric intake is reduced on all diets that extend life span. Flies on low-yeast diet are long-lived and consume about half the calories of flies on high-yeast diets, regardless of the energetic content of the diet itself. Since caloric intake correlates with yeast concentration and thus with the intake of every metabolite in this dietary component, it is premature to conclude for Drosophila that calories do not explain extension of life span.