Acetylcholine (ACh) is the neurotransmitter of the parasympathetic nervous system that modulates cardiac function, and its high concentrations may induce atrial fibrillation. We compared the ACh action on the mechanical function of single cardiomyocytes from the left atria (LA) and the right atria (RA). We exposed single rat LA and RA cardiomyocytes to 1, 10, and 100 µM ACh for 10–15 min and measured the parameters of sarcomere shortening–relengthening and cytosolic calcium ([Ca2+]i) transients during cell contractions. We also studied the effects of ACh on cardiac myosin function using an in vitro motility assay and analyzed the phosphorylation level of sarcomeric proteins. In LA cardiomyocytes, ACh decreased the time to peak sarcomere shortening, time to 50% relengthening, and time to peak [Ca2+]i transients. In RA cardiomyocytes, ACh affected the time of shortening and relengthening only at 10 µM. In the in vitro motility assay, ACh reduced to a greater extent the sliding velocity of F-actin over myosin from LA cardiomyocytes, which was accompanied by a more pronounced decrease in phosphorylation of the myosin regulatory light chain (RLC) in LA cardiomyocytes than in RA cardiomyocytes. Our findings indicate that ACh plays an important role in modulating the contractile function of LA and RA, provoking more pronounced changes in the time course of sarcomere shortening–relengthening and the kinetics of actin–myosin interaction in LA cardiomyocytes.

Ascites occurs in about 60 % of patients with cirrhosis within 10 years of diagnosis. Laparocentesis is the preferred first-line therapy in patients with cirrhosis and massive tense ascites, allowing more than 5–6 liters of ascitic fluid to be removed at one time. The search for informative prognostic factors and the development of a method for predicting unfavorable outcomes of repeated laparocenteses in patients with ascites are relevant to timely refer this contingent of patients to perform TIPS.The purpose of the study was to develop and evaluate the diagnostic significance of a model for determining the probability of unfavorable outcomes of laparocentesis in patients with ascites on the background of liver cirrhosis.The results of treatment of 99 patients with the ascitic syndrome associated with intrahepatic portal hypertension were studied. The multiple regression analysis using the binary response logit model was carried out to calculate the prediction models. The analysis of the treatment results of patients with liver cirrhosis and ascites by the laparocentesis method revealed a number of factors that influence the onset of an unfavorable outcome. 2 models with the inclusion of initial variables are the most promising for forecasting. Model A includes: patient weight, serum-ascites total protein gradient, hyponatremia; model B: MELD-Na score, serum-ascitic total protein gradient, patient weight. The developed prediction method is highly informative, effective, easily applicable, and can be widely used in clinical practice.The ability to predict an unfavorable outcome in patients with portal hypertension and ascites after laparocentesis allows for a personalized approach in the process of timely selection of more effective, but also more expensive treatment methods, such as TIPS, which will help us to increase the therapy effectiveness and the survival of this cohort of patients.

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Purpose. To study magnesium status of patients having paroxysmal atrial fibrillation (AF) based on the use of an integrated clinical and laboratory approach. Methods. A prospective cohort study included 58 patients of the cardiology department of New Hospital Medical Association. The main group consisted of 32 patients having frequently recurring paroxysmal AF, the control group consisted of 26 patients without paroxysmal rhythm disturbance. The clinical status, Holter ECG monitoring data, the test results for magnesium deficiency (MD) clinical evidence, laboratory evidence of calcium, magnesium in blood plasma and formed elements, magnesium in whole blood, free fatty acids (FFA) and osmolality in blood plasma were assessed. Results. The score obtained when assessing MD clinical evidence was significantly higher in the main group patients compared with the control group (16.5 (11÷21) vs. 13 (8÷15), p<0.001). A statistically significant magnesium decrease in whole blood was revealed in patients having paroxysmal AF (0.54 (0.46÷0.60) vs. 0.61 (0.59÷0.64), p<0.001) and inside formed elements (0.68 (0.53÷1.07) vs. 1.31 (1.07÷1.44), p<0.001), which reflected changes in their magnesium status to a greater extent than the measured plasma cation concentrations. A close correlation between magnesium content in formed elements (intracellularly) and AF paroxysms frequency (Spearman’s rank correlation -0.51, p<0.001) was established. A violation of calcium to magnesium ratio in blood plasma (2.6 (2.5÷2.9) vs. 3.0 (2.8÷3.1), p=0.004) and intracellularly (4.85 (2.62÷9.3) vs. 1.85 (1.57÷2.07), p<0.001) was revealed in patients having AF. It has been shown that complex forming interactions with free fatty acids may affect intracellular calcium and magnesium content.

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