Cerebellar binding of avian pancreatic polypeptide

Studies were carried out to determine the regional central nervous system and species specificity of the previously observed [125I]iodoavian pancreatic polypeptide ( [125I]iodo-APP) specific binding to chick brain membranes. The avian species examined were chicken, pigeon, duck, quail, chukar, and pheasant. In all species, the vast majority (greater than 90%) of APP binding was localized to the area of the cerebellum; other brain regions specifically bound small amounts of APP. Cerebellar hemisphere (folia) regions may have greater specific binding capacities than deep cerebellar nuclei, although all avian cerebellar preparations exhibited affinities for APP on the order of 10(-10) M and binding capacities from approximately 0.2-1.5 pmol/mg protein for the high affinity sites. The measured affinity for binding of APP to these cerebellar binding sites is consistent with normal plasma concentrations (3-6 ng/ml) of APP in all Aves examined. Mammalian (rat and beef) brain membranes, regardless of topographical region, showed low specific binding of [125I]iodo-APP and [125I]iodobovine PP. Preliminary experiments indicate that APP is neither contained in nor released from avian central nervous system synaptosomal elements.     

Influence of vasostatins, the chromogranin A-derived peptides, on the working heart of the eel (Anguilla anguilla): negative inotropy and mechanism of action

We have studied the effects of exogenous human recombinant Vasostatin-1 (VS-1), Vasostatin-2 (VS-2) and the human Chromogranin A (CGA) 7-57 synthetic peptides on the mechanical performance of the isolated and perfused working eel (Anguilla anguilla) heart. Under basal conditions, the three peptides decreased stroke volume (SV) and stroke work (SW), thus exerting negative inotropism. The VS-1-mediated negative inotropism was abolished by exposure to inhibitors of either Gi/o protein (pertussis toxin; PTx) or M1 muscarinic receptors (Pirenzepine) or calcium (Lantanum and Diltiazem) and potassium (Ba2+, 4-aminopyridine, tetraethylammonium, glibenclamide) channels, while it required an intact endocardial endothelium (EE). Using NG-monomethyl-L-arginine (L-NMMA) as an inhibitor of nitric oxide (NO) synthase (NOS), and hemoglobin as a NO scavenger, we demonstrated the obligatory role of NO signaling in mediating the vasostatin response. Pretreatment with either a specific inhibitor of soluble guanylate cyclase (GC) 1H-(1,2,4)oxadiazolo-(4,3-a)quinoxalin-1-one (ODQ), or the inhibitor of the cGMP-activated protein kinase (PKG) KT5823, abolished the VS-1-mediated inotropism, indicating the cGMP-PKG component as a crucial target of NO signaling. Of note, VS-1 was effective in counteracting the adrenergic (Isoproterenol and Phenylephrine)-mediated positive inotropism. These findings provide the first evidence that vasostatins exert cardiotropic action in fish, thus suggesting their long evolutionary history as well as their species-specific mechanisms of action.     

Artificial intelligence in gastroenterology: A state-of-the-art review

The development of artificial intelligence (AI) has increased dramatically in the last 20 years, with clinical applications progressively being explored for most of the medical specialties. The field of gastroenterology and hepatology, substantially reliant on vast amounts of imaging studies, is not an exception. The clinical applications of AI systems in this field include the identification of premalignant or malignant lesions (e.g., identification of dysplasia or esophageal adenocarcinoma in Barrett’s esophagus, pancreatic malignancies), detection of lesions (e.g., polyp identification and classification, small-bowel bleeding lesion on capsule endoscopy, pancreatic cystic lesions), development of objective scoring systems for risk stratification, predicting disease prognosis or treatment response [e.g., determining survival in patients post-resection of hepatocellular carcinoma), determining which patients with inflammatory bowel disease (IBD) will benefit from biologic therapy], or evaluation of metrics such as bowel preparation score or quality of endoscopic examination. The objective of this comprehensive review is to analyze the available AI-related studies pertaining to the entirety of the gastrointestinal tract, including the upper, middle and lower tracts; IBD; the hepatobiliary system; and the pancreas, discussing the findings and clinical applications, as well as outlining the current limitations and future directions in this field.     

Effect of L-Carnitine on Ethanol and Acetate Plasma Levels after Oral Administration of Ethanol in Humans

In a randomized double-blind, cross-over experiment, 0.5 g/kg of ethanol in the form of white wine and 3 g of L-carnitine by intravenous infusion were administered to 15 healthy volunteers. Ethanol and acetate plasma levels and the urine concentrations of acetylcarnitine were determined. Administration of ethanol induced a significant increase of both plasma ethanol and acetate, lasting 6-8 hr. The concomitant administration of carnitine resulted in a significant decrease of plasma acetate, whereas plasma ethanol levels remained unmodified. Urinary acetylcarnitine content significantly increased following administration of ethanol plus carnitine, but not when L-carnitine alone was administered. The resulting conclusion is that administered L-carnitine might trap excess acetyls derived both from free acetate, formed by ethanol oxidation, and from acetyl coenzyme A, accumulated as a result of the ethanol-induced decrease in the Krebs cycle flux.     

Predictors and Clinical Impact of Prosthesis-Patient Mismatch After Self-Expandable TAVR in Small Annuli

ObjectivesThe aim of this study was to define predictors of prosthesis-patient mismatch (PPM) and its impact on mortality after transcatheter aortic valve replacement (TAVR) with self-expandable valves (SEVs) in patients with small annuli.BackgroundTAVR seems to reduce the risk for PPM compared with surgical aortic valve replacement, especially in patients with small aortic annuli. Nevertheless, predictors and impact of PPM in this population have not been clarified yet.MethodsPredictors of PPM and all-cause mortality were investigated using multivariable logistic regression analysis from the cohort of the TAVI-SMALL (International Multicenter Registry to Evaluate the Performance of Self-Expandable Valves in Small Aortic Annuli) registry, which included patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm² on computed tomography) treated with transcatheter SEVs: 445 patients with (n = 129) and without (n = 316) PPM were enrolled.ResultsIntra-annular valves conferred increased risk for PPM (odds ratio [OR]: 2.36; 95% confidence interval [CI]: 1.16 to 4.81), while post-dilation (OR: 0.46; 95% CI: 0.25–0.84) and valve oversizing (OR: 0.53; 95% CI: 0.28–1.00) seemed to protect against PPM occurrence. At a median follow-up of 354 days, patients with severe PPM, but not those with moderate PPM, had a higher all-cause mortality rate compared with those without PPM (log-rank p = 0.008). Multivariable Cox regression confirmed severe PPM as an independent predictor of all-cause mortality (hazard ratio: 4.27; 95% CI: 1.34 to 13.6).ConclusionsAmong patients with aortic stenosis and small aortic annuli undergoing transcatheter SEV implantation, use of intra-annular valves yielded higher risk for PPM; conversely, post-dilation and valve oversizing protected against PPM occurrence. Severe PPM was independently associated with all-cause mortality.     

Amyloidosis and pleural disease

Pleural involvement with systemic amyloidosis has been reported rarely in the literature. Diagnosis of this entity by percutaneous needle biopsy of the pleura has been described only in two prior case reports. We describe five patients in whom the diagnosis of pleural amyloidosis was established by Cope needle biopsy during evaluation of pleural effusions of indeterminate cause. Three patients presented with a history suggestive of multiorgan disease and a pleural biopsy performed despite a transudative effusion demonstrated amyloid infiltration of the pleura, obviating the need for other organ biopsies. We conclude that in patients with pleural effusions, if history suggests multiorgan involvement and there is suspicion for amyloidosis, then a closed pleural biopsy with special stains for amyloid should be performed even if the effusions are transudative. This may be the diagnostic procedure of choice in such patients.     

Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.