Ventricle Of Heart Research Articles

Identification and Analysis of Hub Genes in Diabetic Cardiomyopathy: Potential Role of Cytochrome P450 1A1 in Mitochondrial Metabolism and STZ-Induced Myocardial Dysfunction.

Diabetic cardiomyopathy (DCM) is a primary cause of death in diabetic patients; however, its molecular mechanism is not yet clear, and there is no uniform standard for diagnosis. The aim of this study is to discover the pathogenesis and potential therapeutic targets of DCM through screening and analysis of differentially expressed genes (DEGs) in heart ventricles of DCM, and to testify the role of key hub genes in DCM-induced myocardial dysfunction. Datasets GSE4745 and GSE6880 were downloaded from the GEO database. The difference analysis, visual analysis, cluster analysis and enrichment analysis were performed by using R language, python scripts and bioinformatics software followed by the construction of protein-protein interaction (PPI) network to obtain hub genes. The DCM models were established by streptozocin (STZ) injection to the male mice. The cardiac function and the expressions of hub genes were examined by using echocardiography and real-time quantitative poly-merase chain reaction (RT-qPCR), followed by multiple statistical analyses. Bioinformatic results indicate that mitochondrial dysfunction, disturbed lipid metabolism and decreased collagen synthesis are the main causes of the DCM development. In particular, the hub gene Cyp1a1 that encodes Cytochrome P450 1A1 (CYP4501A1) enzyme has the highest connectivity in the interaction network, and is associated with mitochondrial homeostasis and energy metabolism. It plays a critical role in the oxidation of endogenous or exogenous substrates. Our RT-qPCR results confirmed that ventricular Cyp1a1 mRNA level was nearly 12-fold upregulated in DCM model compared to normal control, which was correlated with abnormal cardiac function in diabetic individuals. CYP4501A1 protein expression in mitochondria was also increased in diabetic hearts. However, we found no significant changes in collagen expressions in cardiac ventricles of mice with DCM. This study provided compact data support for understanding the pathogenesis of DCM. CYP4501A1 might be considered as a potential candidate targeting for DCM therapy. Follow-up animal and clinical verifications need to be further explored.

Age- and Hypertension-Related Changes in NOS/NO/sGC-Derived Vasoactive Control of Rat Thoracic Aortae.

This study was aimed at examining the role of the NOS/NO/sGC signaling pathway in the vasoactive control of the thoracic aorta (TA) from the early to late ontogenetic stages (7 weeks, 20 weeks, and 52 weeks old) of normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Systolic blood pressure (SBP) and heart rate (HR) were significantly increased in SHRs compared to age-matched WKYs, which was associated with left heart ventricle hypertrophy in all age groups of rats. The plasma urea level was increased in 20-week-old and 52-week-old SHRs compared with WKYs without increasing creatinine and uric acid. The total cholesterol levels were lower in 20-week-old and 52-week-old SHRs than in WKYs, but triglycerides were higher in 7-week-old SHRs. The fructosamine level was increased in 52-week-old SHRs compared with age-matched WKYs and unchanged in other age groups. Superoxide production was increased only in 7-week-old SHRs compared to age-matched WKYs. The endothelium-dependent relaxation (EDR) of the TA deteriorated in both rat strains during aging; however, endothelial dysfunction already occurred in 20-week-old SHRs and was even more enhanced in 52-week-old rats. Our results also demonstrated increased activity of NOS in 52-week-old WKYs. Moreover, 7-week-old and 52-week-old WKY rats displayed an enhanced residual EDR after L-NMMA (NOS inhibitor) incubation compared with 20-week-old rats. Our results showed that in 7-week-old SHRs, the residual EDR after L-NMMA incubation was increased compared to that in other age groups. The activity of NOS in the TA was comparable in 7-week-old and 20-week-old SHRs, but it was reduced in 52-week-old SHRs compared to younger SHRs and 52-week-old WKYs. Thus, it seems that, in contrast to SHRs, the NOS/NO system in WKYs is probably able to respond to age-related pathologies to maintain endothelial functions and thus optimal BP levels even in later periods of life.

Coronary Sinus Diameter as a Potential Marker of Right Ventricle Impairment.

The aim of this study was to assess the influence of the parameters of the coronary sinus (CS) on the parameters that describe the function of the right ventricle (RV), which were calculated using cardiac computed tomography. Methods: A CT scan of the heart was performed on 150 patients due to suspicion of coronary artery disease using a Siemens Somatom Force (2 × 192 × 0.6) and a syngo.via workstation. The “CT coronary” and in some cases the generic presets were used to measure the CS ostium in millimeters (mm). The functional measurements of right heart ventricles were examined using the “CT cardiac function” automatic function on a 256 × 256 matrix. Results: The average diameter of the CS ostium was 16.29 ± 4.37 mm. In the group with RV impairment, it was 16.56 ± 4.76, whereas in the group with normal values of the RV, it was 15.98 ± 3.88 mm, p = 0.4199. The average angle of the entrance of the CS into the right atrium was 107.25° ± 9.68°. In the group with an RV impairment, it was 105.91° ± 9.22°, while in the patients with normal values of the RV, it was 108.82° ± 10.04°; p = 0.0682. A multiple regression showed that end systolic volume (p = 0.0017) and stroke volume (p = 0.0144) are important predictors of the CS ostium. Conclusions: Some relationships were found between the CS and the selected parameters that describe the function of the RV. This may suggest a role for the CS as a right ventricular buffer, which could potentially be treated as a marker of an RV impairment.

Transcriptomic Signatures of End-Stage Human Dilated Cardiomyopathy Hearts with and without Left Ventricular Assist Device Support.

Left ventricular assist device (LVAD) use in patients with dilated cardiomyopathy (DCM) can lead to a differential response in the LV and right ventricle (RV), and RV failure remains the most common complication post-LVAD insertion. We assessed transcriptomic signatures in end-stage DCM, and evaluated changes in gene expression (mRNA) and regulation (microRNA/miRNA) following LVAD. LV and RV free-wall tissues were collected from end-stage DCM hearts with (n = 8) and without LVAD (n = 8). Non-failing control tissues were collected from donated hearts (n = 6). Gene expression (for mRNAs/miRNAs) was determined using microarrays. Our results demonstrate that immune response, oxygen homeostasis, and cellular physiological processes were the most enriched pathways among differentially expressed genes in both ventricles of end-stage DCM hearts. LV genes involved in circadian rhythm, muscle contraction, cellular hypertrophy, and extracellular matrix (ECM) remodelling were differentially expressed. In the RV, genes related to the apelin signalling pathway were affected. Following LVAD use, immune response genes improved in both ventricles; oxygen homeostasis and ECM remodelling genes improved in the LV and, four miRNAs normalized. We conclude that LVAD reduced the expression and induced additional transcriptomic changes of various mRNAs and miRNAs as an integral component of the reverse ventricular remodelling in a chamber-specific manner.

Engineering in-plane mechanics of electrospun polyurethane scaffolds for cardiovascular tissue applications

Effective cardiovascular tissue surrogates require high control of scaffold structural and mechanical features to match native tissue properties, which are dependent on tissue-specific mechanics, function heterogenicity, and morphology. Bridging scaffold processing variables with native tissue properties is recognized as a priority for advancing biomechanical performance of biomedical materials and, when translated to the clinical practice, their efficacy. Accordingly, this study selected electrospinning on a rotating cylindrical target as an apparatus of broad application and mapped the relationship between key processing variables and scaffold mechanics and structure. This information was combined with mechanical anisotropy ranges of interest for the three main categories of tissue surrogated in cardiovascular tissue engineering: heart valve leaflets, ventricle wall, and large diameter blood vessels. Specifically, three processing variables have been considered: the rotational velocity and the rastering velocity of the mandrel and the dry (single nozzle – polymer only) vs wet (double nozzle – polymer plus phosphate buffer saline solution) fabrication configuration. While the dry configuration is generally utilized to obtain micro-fiber based polymeric mats, the wet fabrication is representative of processing conditions utilized to incorporate cells, growth factors, or micro-particles within the fibrous scaffold matrix. Dry and wet processed electrospun mats were fabricated with tangential and rastering velocities within the 0.3–9.0 m/s and 0.16–8 cm/s range respectively. Biaxial mechanics, fiber network, and pore micro-architectures were measured for each combination of velocities and for each fabrication modality (dry and wet). Results allowed identification of the precise combination of rotational and rastering velocities, for both dry and wet conditions, that is able to recapitulate the native cardiovascular tissue anisotropy ratio. By adopting a simple and broadly utilized electrospinning layout, this study is meant to provide a repeatable and easy to access methodology to improve biomimicry of the in plane-mechanics of heart valve leaflets, ventricular wall, and large diameter blood vessels.

Comparison of left versus right ventricular contraction profile in failing and non-failing isolated human myocardium

The left ventricle (LV) and right ventricle (RV) of human heart demonstrate significant differences in embryology, form, and function. RV dysfunction may develop in association with LV dysfunction via multiple mechanisms. Conversely, RV pressure overload, as may occur with pulmonary hypertensive states, may compromise LV function. Our objective was to investigate the relationship of LV to RV contractile performance and examine the influence of heart failure (HF) on these relationships. Myocardial LV and RV trabeculae were dissected from non-failing (NF) and end-stage failing human hearts.

Molecular characterization of zoonotic anisakid Contracaecum spp. larvae in some fish species from Lake Nasser, Egypt

Infections with zoonotic anisakid nematode larvae Contracaecum spp. were detected in five fish species from Lake Nasser, Egypt: three tilapia species (Oreochromis niloticus, Sarotherodon galilaeus and Tilapia zillii) and two catfish species (Malapterurus electricus and Heterobranchus bidorsalis). Severely infected fish displayed general body emaciation and distended abdomen. The overall prevalence of infection was 30% (tilapia species 24.17% and catfish 41.67%). The larvae were morphologically identified as third stage larvae of Contracaecum. The internal transcribed spacer sequences of nuclear ribosomal DNA (ITS-1 and ITS-2) were used for molecular characterization, resulting in the submission of six new sequences to the GenBank database and confirming that the present larvae were members of the C. multipapillatum complex (C. multipapillatum and C. quadripapillatum). The phylogenetic analysis corroborated the molecular results and demonstrated Contracacum's polyphyletic nature. The larvae aggressively bore into the heart ventricle of tilapia species (Heartworm Disease), causing severe pathological changes such as myocardial fibre atrophy, interstitial haemorrhage, pericarditis with eosinophilic granular cells infiltration and intravascular thrombosis, and impairing heart function, whereas in catfish, the larvae encapsulated in the abdominal cavity and caused little harm. As a result, they are the causative agent of Heartworm Disease.

Cooling intact and demembranated trabeculae from rat heart releases myosin motors from their inhibited conformation.

Myosin filament-based regulation supplements actin filament-based regulation to control the strength and speed of contraction in heart muscle. In diastole, myosin motors form a folded helical array that inhibits actin interaction; during contraction, they are released from that array. A similar structural transition has been observed in mammalian skeletal muscle, in which cooling below physiological temperature has been shown to reproduce some of the structural features of the activation of myosin filaments during active contraction. Here, we used small-angle x-ray diffraction to characterize the structural changes in the myosin filaments associated with cooling of resting and relaxed trabeculae from the right ventricle of rat hearts from 39°C to 7°C. In intact quiescent trabeculae, cooling disrupted the folded helical conformation of the myosin motors and induced extension of the filament backbone, as observed in the transition from diastole to peak systolic force at 27°C. Demembranation of trabeculae in relaxing conditions induced expansion of the filament lattice, but the structure of the myosin filaments was mostly preserved at 39°C. Cooling of relaxed demembranated trabeculae induced changes in motor conformation and filament structure similar to those observed in intact quiescent trabeculae. Osmotic compression of the filament lattice to restore its spacing to that of intact trabeculae at 39°C stabilized the helical folded state against disruption by cooling. The myosin filament structure and motor conformation of intact trabeculae at 39°C were largely preserved in demembranated trabeculae at 27°C or above in the presence of Dextran, allowing the physiological mechanisms of myosin filament-based regulation to be studied in those conditions.

Morphology and specifics of morphometry of lungs and myocardium of heart ventricles of cattle, sheep and horses

Respiratory organs and cardiovascular system are interconnected and perform extremely vital functions of the organism, the main goals being performing gas exchange with the environment and emitting carbon dioxide produced in the organism into the environment. Therefore, we carried out comparative histo- and cytomorphometric evaluation of morphological structures of the heart and lungs of cattle, sheep and horses. Using complex methods of research, we determined specifics of microscopic structure and histometric parameters of parenchyma of the lungs and myocardium of the ventricles of the hearts of clinically healthy animals in species aspect – cattle, sheep and horses. The studies revealed that the histoarchitectonics of the studied animals were similar in structure, characteristic of other species of agricultural mammals, and distinct morphometric peculiarities of their histostructures. The study indicated that the respiratory zone of the lungs is most developed in horses. This parameter was lower in ruminants – cattle and sheep. Connective tissue septum of parenchyma of lungs was better expressed in cattle and sheep, and less in horses. At the same time, mean volume of lung alveoli in clinically healthy animals varied: being highest in horses – 699 ± 106 thou µm3, then cattle – 337 ± 43 thou µm3 and sheep – 158 ± 37 thou µm3. Such variation in histometric parameters of parenchyma of the lungs in experimental animals indicates adaptive specifics of the organism of animals in terms of living conditions. Therefore, the respiratory zone was most developed in the lungs of horses, animals that experience significant physical and physiological load on corresponding organs and systems. As a result of histometric studies of myocardium, we determined patterns of sizes of thickness of its cardiomyocytes and volume of their nuclei. We determined that in myocardium of the heart ventricles, in the same microscope field of view, cardiomyocytes of varying thicknesses occur. At the same time, thickness of cardiomyocytes, their mean volume of nuclei in the ventricle myocardium were expressed the most in cattle, then in horses and sheep, and their histometric parameters in myocardium of the left ventricle of the heart in the experimental animals were higher than in the right one. Therefore, thickness of cardiomyocytes of the left ventricle in cattle equaled 14.06 ± 0.41 µm, and volume of nuclei of cardiomyocytes respectively 124.55 ± 7.99 µm3. Similar changes in such parameters of histometry were found in sheep and horses. We attribute such varying histometric parameters of the thickness of cardiomyocytes and volume of their nuclei in myocardium of the left ventricle of the heart in experimental animals, compared with such parameters in the right ventricle, to the activities of the ventricles (the left one generally functions as a pump, right one – as a volumetric) and functional specifics of this myocardium tissue, which is capable of spontaneous rhythmic contractions, resulting in blood flow in the vessels: cardiomyocytes of the left ventricle carry greater load, promoting blood flow in vessels of greater (somatic) blood circulation, respectively cardiomyocytes of the right ventricle – less load, promoting blood flow in vessels of lesser (pulmonary) blood circulation.

Mast cells and basic fibroblast growth factor in physiological aging of rat heart and kidney

ABSTRACT Age-related morphological and physiological changes occur in cells, tissues and organs with high metabolic or mitotic activity; these changes decrease their regenerative capacity. One such change is interstitial fibrosis. Mast cells contain basic fibroblast growth factor and have been related to pro-fibrotic activity. We investigated the role of mast cells in physiological aging of the heart and kidney. We analyzed changes in mast cell number and compared the left and right heart ventricles and kidneys of 6- and 12-month-old Wistar rats. We also evaluated the immunohistochemical expression of basic fibroblast growth factor. Finally, we analyzed changes in the extent of interstitial fibrosis and in the glomerular sclerosis index as nonspecific markers of aging and correlated these parameters with of mast cells. Mast cells were visualized by toluidine blue staining and specific immunohistochemical expression of tryptase. The expression of basic fibroblast growth factor was assessed semiquantitatively. The extent of interstitial fibrosis was investigated using Mallory’s trichrome staining. Glomerular sclerosis was evaluated using periodic acid-Schiff staining. We found that the number of mast cells increased significantly in the older rats. We also found that the number of mast cells was greatest in the left ventricle followed by the right ventricle, then the kidney. The immunoreactivity of basic fibroblast growth factor also increased in older animals. Correlations between the number of mast cells and immunoreactivity of basic fibroblast growth factor, extent of interstitial fibrosis and glomerular sclerosis index demonstrated the association between mast cells and age-related tissue remodeling of the heart and kidney.

Roles of stretch-activated channels and NADPH oxidase 2 in the induction of twitch contraction by muscle stretching in rat ventricular muscle

Mechano-electric feedback means that muscle stretching causes depolarization of membrane potential. We investigated whether muscle stretching induces action potential and twitch contraction with a threshold of sarcomere length (SL) and what roles stretch-activated channels (SACs) and stretch-activated NADPH oxidase (X-ROS signaling) play in the induction. Trabeculae were obtained from the right ventricles of rat hearts. Force, SL, and [Ca2+]i were measured. Various degrees of stretching from the SL of 2.0μm were applied 0.5s after the last stimulus of the electrical train with 0.4-s intervals for 7.5s. The SLtwitch was defined as the minimal SL at which twitch contraction was induced by the stretching. Muscle stretching induced twitch contraction with a threshold of SL at 0.4-s stimulus intervals ([Ca2+]o = 0.7mmol/L). The SLtwitch was not changed by increasing the stimulus intervals and [Ca2+]o and by adding 1μmol/L isoproterenol. The SLtwitch was not changed by adding 10μmol/L Gd3+, 100μmol/L or 200μmol/L streptomycin, and 5μmol/L GsMTx4. The SLtwitch was not changed by adding 1μmol/L ryanodine and 3μmol/L diphenyleneiodonium chloride. In contrast, the SLtwitch was increased by elevating extracellular K+ from 5 to 10mmol/L and by adding the stretching during the refractory period of membrane potential. The addition of the stretching-induced twitch contraction more frequently induced arrhythmias. These results suggest that muscle stretching can induce twitch contraction with a threshold of SL and concern the occurrence of arrhythmias and that SACs and X-ROS signaling play no roles in the induction.

Vectorcardiographic Ventricular Gradient with Constituents, and Myocardial Action Potential Parameter Distribution

AbstractTheoretical grounds of integral vectors of ventricular depolarization and repolarization and their sum, i.e., the spatial ventricular gradient, have been studied. A systematic description and biophysical interpretation of these parameters are presented based on the distribution of cardiomyocyte action potential parameters in the inhomogeneous bidomain model of the myocardium. Recent medical studies have shown high efficiency and predictive value of the ventricular gradient, its constituents and related parameters, such as the angle between the con-stituents, the acceleration of repolarization, etc. Simple examples for a myocardial strip clarify the relationship between the action potential parameters and the resulting ventricular gradient. An explanation with graphic illustration is given for the very informative decartogram of repolarization acceleration. The results obtained here are useful in the modeling of vectorcardiograms for various pathological conditions of the heart ventricles and for various characteristics of the cardiomyocyte action potential, which determine its shape.

Construction of a mechanical model of the human heart left ventricle in the process of its contraction

A detailed analysis of previous works on modeling the left ventricle (LV) of the human heart, starting with mechanical models in the form of the simplest three-dimensional figures (cylinder, sphere, ellipsoid of rotation) and ending with models using real contours of the human heart obtained by ultrasound examination of the human heart. A way of constructing a mechanical LV model based on the processing of its dynamic images obtained using computer and magnetic resonance imaging was proposed. Digitization of these images was carried out using numerical methods developed to create a finite element model were implemented in the CMISS system, which allows the use of finite element analysis methods to solve various complex problems. To avoid the need to operate with huge arrays of numbers (up to 10 thousand numerical values at each time of the MRI study) characteristic points of the three-dimensional LV image were selected and spline interpolation of the model framework written in C++ using the Cmgui module was performed. To describe the work of the mechanical model of LV reduction, the main components of this process were identified: transverse compression, longitudinal contraction and twisting. To describe them, simple mathematical characteristics were used.

Comparison of Dosimetric Parameters of Three- Dimensional Conformal Radiotherapy and Intensity- Modulated Radiotherapy in Breast Cancer Patients Undergoing Adjuvant Radiotherapy after Modified Radical Mastectomy

Introduction Adjuvant radiotherapy has an important role in preventing locoregional recurrences. But radiation-induced late sequelae have become an important area of concern. The ideal postmastectomy radiotherapy technique is an area of controversy. The present study was designed to compare two widely practiced conformal techniques, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), in terms of dosimetry. Material and Methods A total of 50 postmodified radical mastectomy patients were selected and were randomized to treatment either by 3DCRT or IMRT technique. Two opposing tangential beams were used in 3DCRT plans whereas five to seven tangential beams were used for IMRT plans. The prescribed dose was 50 Gy in 25 fractions over 5 weeks. The dosimetric parameters were compared for planning target volume (PTV), lungs, heart, and left ventricle, opposite breast and esophagus. Results The dosimetric parameters of PTV in terms of D95%, D90%, D50%, and Dmean showed no significant difference among both techniques. The IMRT technique had significantly better mean values of Dnear-min/D98% (45.56 vs. 37.92 Gy; p = 0.01) and Dnear-max/D2% (51.47 vs. 53.65 Gy; p < 0.001). Also, conformity index (1.07 vs. 1.29; p = 0.004) and homogeneity index (0.22 vs. 0.46; p = 0.003) were significantly better in IMRT arm. The dosimetric parameters of ipsilateral lung were significantly higher in IMRT arm in terms of mean dose (19.92 vs. 14.69 Gy; p < 0.001) and low/medium dose regions (V5, V10, V13, V15, V20; p < 0.05). However, high-dose regions (V40) were significantly higher in 3DCRT arm (15.57 vs. 19.89 Gy; p = 0.02). In contralateral lung also, mean dose was significantly higher in IMRT technique (3.63 vs. 0.53 Gy; p < 0.0001) along with low-dose regions (V5, V10, V13, V15; p < 0.05) while V20 was comparable between both the arms. In left-sided patients, the heart dose favored 3DCRT technique in terms of mean dose (17.33 vs. 8.51 Gy; p = 0.003), low/medium dose regions (V5, V10, V20; p < 0.05), and doses to partial/whole volumes (D33, D67, D100). But the high-dose regions (V25, V30, V40) were comparable between both the arms. The dosimetry of left ventricle also showed significantly lesser values of mean dose and V5 in 3DCRT technique (p < 0.0001). The opposite breast also showed higher mean dose with IMRT technique (2.60 vs. 1.47 Gy; p = 0.009) along with higher V5 (11.60 vs. 3.83 Gy; p = 0.001). The dosimetric parameters of esophagus showed higher mean dose in IMRT technique (10.04 vs. 3.24 Gy; p < 0.0001) but the high-dose regions V35 and V50 were comparable between both the arms. Conclusion A clear advantage could not be demonstrated with any of the techniques. The IMRT technique led to more conformal and homogenous dose distribution with reduction in high-dose regions in ipsilateral lung while the 3DCRT technique showed lesser mean dose to organs at risk (OARs). The exposure of large volumes of OARs to low doses in IMRT technique may translate to increased long-term radiation-induced complications. The shortcomings of 3DCRT technique can be overcome by using multiple subfields within tangential fields.

Stingless bee propolis, metformin, and their combination alleviate diabetic cardiomyopathy

Background and aim: Stingless bee propolis, a resinous compound processed by mandibular secretion of stingless bees, is used for maintenance of hygiene and stability of beehives. Research on stingless bee propolis shows therapeutic properties attributed to polyphenols exhibiting antioxidative, antihyperglycemic and antiischemic effect. However, the cardioprotective effect of stingless bee propolis on diabetic cardiomyopathy is unknown. Methods: Adult male Sprague Dawley rats were randomised to five groups: normal group, diabetic group, diabetic given metformin (DM+M), diabetic given propolis (DM+P) and diabetic given combination therapy (DM+M+P) and treated for four weeks. Body weight, fasting blood glucose, food and water intake were taken weekly. At the end of experiment, biomarkers of oxidative damage were measured in serum and heart tissue. Antioxidants in heart tissue were quantified. Part of left ventricle of heart was processed for histological staining including Haematoxylin and Eosin (H&E) stain for myocyte size and Masson’s Trichrome (MT) stain for heart fibrosis and perivascular fibrosis. Results: Propolis alleviated features of diabetic cardiomyopathy such as myocyte hypertrophy, heart fibrosis and perivascular fibrosis associated with improvement in antioxidative status. Conclusion: This study reports beneficial effect of propolis and combination with metformin in alleviating histopathological feature of diabetic cardiomyopathy by modulating antioxidants, making propolis an emerging complementary therapy.

Approximation model for measuring the end diastolic volume of an artificial heart ventricle

Approximation model for measuring the end diastolic volume of an artificial heart ventricle

Proof of Concept: Comparative Accuracy of Semiautomated Vr Modeling for Volumetric Analysis of the Heart Ventricles

Proof of Concept: Comparative Accuracy of Semiautomated Vr Modeling for Volumetric Analysis of the Heart Ventricles

Subepicardial burn injuries in bullfrog heart induce electrocardiogram changes mimicking inferior wall myocardial infarction.

Using bullfrog hearts, we previously reproduced a ST segment elevation in electrocardiogram (ECG), mimicking human ischemic heart disease. In the present study, by inducing subepicardial burn injuries on the inferior part of the frog heart ventricle, we could reproduce typical ECG changes observed in human inferior wall myocardial infarction, such as the marked elevation of the ST segments in inferior limb leads (II, III, aVF) and their reciprocal depression in the opposite limb leads (I, aVL). Due to the decrease in Na+/K+-ATPase protein expression, the resting membrane potential of injured cardiomyocytes shifted toward depolarization. Such induced electrical difference between the injured and intact cardiomyocytes was thought to be responsible for the creation of “currents of injury” and the subsequent ST segment changes.

Aerobic scope is not maintained at low temperature and is associated with cardiac aerobic capacity in the three-spined stickleback Gasterosteus aculeatus.

Metabolic thermal plasticity is central to the survival of fishes in a changing environment. The eurythermal three-spined stickleback Gasterosteus aculeatus displays thermal plasticity at the cellular level with an increase in the activity of key metabolic enzymes in response to cold acclimation. Nonetheless, it is unknown if these changes are sufficient to completely compensate for the depressive effects of cold temperature on whole organismal metabolic rate (ṀO2 ). The authors hypothesized that as a cold-tolerant, eurythermal fish, absolute aerobic scope (AAS), the difference between the maximum metabolic rate (MMR) and standard metabolic rate (SMR), would be maintained in G. aculeatus following acclimation to a range of temperatures that span its habitat temperatures. To test this hypothesis, G. aculeatus were acclimated to 5, 12 and 20°C for 20-32 weeks, and SMR, MMR and aerobic scope (AS) were quantified at each acclimation temperature. The maximal activity of citrate synthase (CS), a marker enzyme of aerobic metabolism, was also quantified in heart ventricles to determine if cardiac aerobic capacity is associated with AS at these temperatures. SMR increased with acclimation temperature and was significantly different among all three temperature groups. MMR was similar between animals at 5 and 12°C and between animals at 12 and 20°C but was 2.6-fold lower in fish at 5°C compared with those at 20°C, resulting in a lower AAS in fish at 5°C compared with those at 12 and 20°C. Correlated with a higher AAS in animals acclimated to 12 and 20°C was a larger relative ventricular mass and higher CS activity per 100 g body mass compared with animals at 5°C. Together, the results indicate that despite their eurythermal nature, AS is not maintained at low temperature but is associated with cardiac aerobic metabolic capacity.

Difference in Thickness Between Right Ventricle and Left Ventricle of Adult Human Heart: A Cadaveric Study

Background: The left ventricle is longer and narrower than the right ventricle, extending from its base in the plane of the atrioventricular groove to the cardiac apex. The wall of the left ventricle is three times thicker (8-12 mm) than those of right ventricle. The wall of the right ventricle is relatively thin (3–5 mm), the ratio of the thickness of the two ventricular walls usually being 1:3. Hypertrophic cardiomyopathy is characterized by myocardial wall thickening, particularly a disproportionate thickening of the interventricular septum in comparison with the posterior wall. An athlete’s heart may physiologically hypertrophy but in a uniform fashion. The objective of the study is to determine the thickness of wall of right and left ventricle of adult human heart and ratio of thickness of right and left ventricle. Materials and Methods: Adult human hearts were procured from the specimens preserved in Anatomy Department of Jawaharlal Nehru Institute of Medical Sciences. A cross-sectional study was conducted on forty- four specimen of adult heart. The measurement of the right and left ventricular wall was done with digital vernier caliper. The measurements were done at three levels in both right and left ventricle: upper, middle and lower part. Result and Conclusion: The ratio of the thickness of the wall of right and left ventricle is well known as 1:3. However, in our study we found the ratio as 1:1.4. We found the thickness of the right ventricle thicker than the normal thickness reported in previous studies. We wish to continue the study with a larger sample size. KEY WORDS: Heart, Right ventricle, left ventricle, Thickness Ratio, Myocardium.