The lipophilic cationic radiotracer 99m Tc-sestamibi, known to be concentrated within mitochondria, is widely used for myocardial perfusion and to a lesser extent for muscle metabolism imaging. However, the exact distribution pattern in skeletal muscle has not been yet studied in detail. The present study aims to investigate the 99m Tc-sestamibi uptake in rat skeletal muscle and myocardium in relation to their metabolic characteristics. 99m Tc-sestamibi was i.v. administered in twenty adult male Wistar rats and uptake, as percent of injected dose per tissue gram (%ID/g), in the myocardium, soleus, extensor digitorum longus and gastrocnemius muscles was assessed 2 h after the injection. Muscle uptake was also correlated with myocardial uptake, muscle weight and body weight. Skeletal muscle 99m Tc-sestamibi uptake was a small (9-16 %) fraction of that found in myocardium (1.71 ± 0.63 %ID/g). Among the three hindlimb muscles considered, the slow-oxidative soleus muscle showed the highest uptake (0.28 ± 0.16 %ID/g). Metabolically diverse parts of the gastrocnemius muscle showed different uptake. Skeletal muscle uptake was positively correlated with myocardial uptake and both were negatively correlated with tissue and body weight. Skeletal muscle and myocardium 99m Tc-sestamibi uptake is related to their metabolic profile. Myocardium, with an exceptional rich mitochondrial concentration, shows much higher 99m Tc-sestamibi uptake compared to skeletal muscles. Among muscles, uptake is dependent on their mitochondrial content. Evidence of matching exists between myocardial and muscle uptake, and both are size-dependent., G. Arsos ... [et al.]., and Obsahuje seznam literatury
Hypertension-induced myocardial metabolic, structural and electrophysiological remodeling deteriorates with aging and contributes to both heart failure and occurrence of malignant arrhythmias. It has been shown in clinical trials that n-3 polyunsaturated fatty acids (n-3 PUFA) reduce the incidence of cardiovascular diseases and sudden cardiac death. We investigated the cardioprotective effects of n-3 PUFA in aged spontaneously hypertensive rats (SHR) and possible cellular mechanisms involved. Male and female 14-month-old SHR were fed with n-3 PUFA (Vesteralens, Norway, 20 mg/day for two months) and compared with untreated SHR. Results showed that n-3 PUFA supplementation led to 1) significant decline of blood pressure; 2) suppression of inducible ventricular fibrillation (VF) by 57 % (male) and 67 % (female) , although the arrhythmogenic substrates, like fibrosis, hypertrophy and abnormal gap junctions distribution were not eliminated; 3) preservation of the cardiomyocytes and the inte grity of their junctions; 4) enhancement of energetic metabolism enzyme activity; 5) augmentation of capillary density associated with increased alkaline phosphatase and decreased dipeptidyl peptidase-4 (DPP4) activity and 6/ increase in gap junction channel connexin-43 expression. Thus, aged male as well as female SHR benefit from n-3 PUFA supplementation that results in decrease in VF susceptibility, partly due to an improvement of myocardial metabolic state, cardiomyocyte and cell-to-cell junctions integrity and Cx43 up-regulation., M. Mitašíková, S. Šmidová, A. Mascaliová, V. Knezl, K. Dlugošová, Ľ. Okruhlicová, P. Weismann, N. Tribulová., and Obsahuje bibliografii a bibliografické odkazy
Cíl: Seznámit čtenáře s provedením dobutaminového testu a SPECTu myokardu ve spolupráci s oddělením funkční diagnostiky. Metodika: Podmínky k vyšetřením vznikly v roce 1996, kdy bylo vybudováno detašované pracoviště KNM v prostorách interní kliniky v blízkosti laboratoří funkční diagnostiky (od roku 2012 součástí Kardiovaskulárního centra FNO). Pacienty indikované k vyšetření objednává odborný internista, kardiolog nebo kardiochirurg na oddělení funkční diagnostiky. Datum vyšetření je nahlášen na ambulanci detašovaného pracoviště KNM. V den vyšetření se pacient hlásí na KNM k zajištění žilního vstupu flexibilní kanylou. S dokumentací je předán na funkční diagnostické oddělení. Kardiolog určuje v průběhu dobutaminové infúze její rychlost. Při dosažení požadované tepové frekvence lékař KNM provede aplikaci RF (99mTc-MIBI, 99mTc-tetrofosmin). Po stabilizaci stavu je pacient předán na KNM, kde je proveden gated SPECT (single photon emission computed tomography) myokardu. V případě patologického nálezu při zátěžové studii je pacient zván k vyšetření za klidových podmínek s odstupem minimálně 24 hodin. Obě pracoviště si navzájem předávají závěrečné protokoly z vyšetření. Závěr: Pomocí nových nukleárně kardiologických softwarů lze automaticky kvantifikovat rozsah a závažnost perfuzních abnormalit. Dobutaminový test je nejrozšířenějším neinvazivním zátěžovým testem, je mnohem specifičtější pro výběr pacientů s indukovatelnou myokardiální ischémií. Obě vyšetřovací metody jsou v dnešní době komplementárními diagnostickými metodami při primodiagnostice ischemické choroby srdeční (ICHS), ve stratifikaci rizika, stanovení prognózy a dalšího terapeutického postupu u pacientů s již známou diagnózou ICHS. Provedení dobutaminového testu a SPECTu myokardu má pro pacienty zásadní přínos z hlediska jejich další léčby., x, Drahoslava Nováková, Jaroslav Šipula, Radoslava Drozdková, Otakar Kraft, Martin Havel, and Literatura
The myocardium examination by MR spectroscopy is very challenging due to movements caused by the cardiac rhythm and breathing. The aim of the study was to investigate the influence of breathing on the quantitative measurement of lipid/water ratios in different groups of volunteers and different measuring protocols. We examined the lipid content of myocardium at 3T using the proton single voxel spectroscopy. Three protocols (free breathing, breath hold and the use of respiratory navigator) controlled by ECG were used for t he examination of 42 adult volunteers including 14 free divers. Spectra were evaluated using jMRUI software. An average content of lipids in the healthy interventricular septum, gained by all protocols was equal to 0.6 %, which is in agreement with other p ublished data. Based on the quality of examinations and the highest technical success, the best protocol seems to be the one containing a respiratory navigator since it is more acceptable by patients. Based on our results and the literature data we can con clude that MR spectroscopy is able to distinguish patients from controls only if their myocardial lipid content is higher than 1.6 % (mean value of lipids plus two standard deviations)., M. Drobny, P. Sedeivy, M. Dezortova, D. Wagnerova, M. Hajek., and Obsahuje bibliografii
Cíl: Prospektivní sledování pacientů po prodělané akutní myokarditidě s cílem posoudit přínos a bezpečnosti pravidelného sledování pacientů pomocí magnetické rezonance (MR), laboratorních hodnot kardiospecifických enzymů a bicyklové ergometrie s ohledem na možné zkrácení doporučovaného přísného klidového režimu. Metodika: U 21 pacientů s diagnostikovanou akutní myokarditidou (včetně přítomnosti pozdního sycení - LGE při vstupní MR) byla v intervalu 1 a 6 měsíců provedena kontrolní MR, stanovení hladiny hypersenzitivního troponinu I (hs-Tn) a bicyklová ergometrie. Obrazová analýza byla zaměřena na vývoj rozsahu a intenzity LGE lézí v MR, výsledky byly porovnány s vývojem hs-Tn a výsledku bicyklové ergometrie po 1 měsíci. Výsledky: Předběžné výsledky studie prokázaly, že u všech pacientů byla prokázána regrese rozsahu i intenzity LGE při kontrolních vyšetřeních a zároveň nebyl prokázán rozvoj systolické dysfunkce levé komory srdeční u žádného pacienta. Tento vývoj korespondoval s vývojem průměrné hodnoty hs-Tn (z 9214,2 µg/1 na 25,4 µg/1). Při bicyklové ergometru nebyly prokázány závažné arytmie a všichni pacienti prokázali dobrou toleranci fyzické zátěže (minimálně 150 W). Závěr: Předběžné výsledky naší studie ukazují, že kombinace magnetické rezonance, hodnoty hs-Tn a bicyklové ergometrie je bezpečná a přínosná pro sledování pacientů po prodělané akutní myokarditidě. Důkladná analýza provedených výše uvedených vyšetření v delších intervalech je nezbytná pro možnou stratifikaci rizika u pacientů i s ohledem na délku doporučeného klidového režimu., Aim: Prospective study of patients following an acute myocarditis in order to assess the benefits and safety of regular monitoring using MRI, laboratory values of cardiac enzymes and exercise ECG. Methods: 21 patients with acute myocarditis (diagnosis including the presence of late gadolinium enhancement - LGE at acute MR) underwent in 1 and 6 months interval a follow-up MRI, level of hypersensitive tro-ponin I (hs-Tn) and the exercise ECG. Image analysis was focused on the development of LGE extent and intensity, results were compared with the development of hs-Tn and exercise ECG in 1 month follow-up. Results: Preliminary results of the study prove regression of the extent and intensity of LGE in all patients and normal left ventricular systolic function in all patients in 1 and 6 months follow-up. This trend corresponds with the development of the average value of hs-Tn (from 9214.2 µg/1 to 25.4 µg/1). During exercise ECG severe arrhythmia was not identified and all patients showed good tolerance of physical burden (at least 150 W). Conclusion: Preliminary results of our study indicate that the combination of MR, the value of hs-Tn and exercise ECG is safe and beneficial for follow-up of patients after acute myocarditis. A thorough analysis at longer intervals is necessary for possible risk stratification of patients with regard to the duration of recommended rest interval duration., Jakub Šedivý, Jan Baxa, Milan Hromádka, Táňa Matoušková, Richard Rokyta, Jiří Ferda, and Literatura
Although exposure to continuous light is associated with hypertension and modulates the outcome of ischemiareperfusion injury, less attention has been paid to its effects on cardiac morphology. We investigated whether 4-week exposure of experimental rats to continuous 24 h/day light can modify cardiac morphology, with focus on heart weight, fibrosis and collagen I/III ratio in correlation with NO-synthase expression. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light. After 4 weeks of treatment the absolute and the relative heart weights were determined and myocardial fibrosis and collagen type I/III ratio were evaluated using picrosirius red staining. Endothelial and inducible NO-synthase expression was detected immunohistochemically. The exposure of rats to continuous light resulted in an increase of body weight with proportionally increased heart weight. Myocardial fibrosis remained unaffected but collagen I/III ratio increased. Neither endothelial nor inducible NO-synthase expression was altered in light-exposed rats. We conclude that the loss of structural homogeneity of the myocardium in favor of collagen type I might increase myocardial stiffness and contribute to functional alterations after continuous light exposure., L'. Paulis, R. Važan, F. Šimko, O. Pecháňová, J. Styk, P. Babál, P. Janega., and Obsahuje bibliografii
Normal increase in hemodynamic load during early postnatal life is associated with heart growth and maturation of membrane structures that is accompanied by remodeling of membrane protein and lipid components. This review describes remodeling of phospholipids (PL) in rat myocardium during normal postnatal development and during accelerated cardiac growth induced by additional workload (aorta constriction, chronic hypoxia and hyperthyroidism) imposed on the heart early after birth. Normal physiological load after birth stimulates the development of membrane structures and synthesis of PL. While hyperthyroidism accelerates these processes, pressure overload has an inhibitory effect. These changes primarily influence the maturation of mitochondrial membranes as cardiolipin is one of the most affected PL species. The most sensitive part of PL structure in their remodeling process are PL acyl chains, particularly polyunsaturated fatty acids that are the key components determining the basic physicochemical properties of the membrane bilayer and thus the function of membrane-bound proteins and membrane-derived signaling lipid molecules. It is evident that PL remodeling may significantly influence both normal and pathological postnatal development of myocardium., F. Novák ... [et al.]., and Obsahuje seznam literatury