The MEK-ERK signaling pathway promotes maintenance of cardiac chamber identity

Ventricular and atrial cardiac chambers have unique structural and contractile characteristics that underlie their distinct functions. The maintenance of chamber-specific features requires active reinforcement, even in differentiated cardiomyocytes. Previous studies in zebrafish have shown that sustained FGF signaling acts upstream of Nkx factors to maintain ventricular identity, but the rest of this maintenance pathway remains unclear. Here, we show that MEK1/2-ERK1/2 signaling acts downstream of FGF and upstream of Nkx factors to promote ventricular maintenance. Inhibition of MEK signaling, like inhibition of FGF signaling, results in ectopic atrial gene expression and reduced ventricular gene expression in ventricular cardiomyocytes. FGF and MEK signaling both influence ventricular maintenance over a similar timeframe, when phosphorylated ERK (pERK) is present in the myocardium. However, the role of FGF-MEK activity appears to be context-dependent: some ventricular regions are more sensitive than others to inhibition of FGF-MEK signaling. Additionally, in the atrium, although endogenous pERK does not induce ventricular traits, heightened MEK signaling can provoke ectopic ventricular gene expression. Together, our data reveal chamber-specific roles of MEK-ERK signaling in the maintenance of ventricular and atrial identities.

How I do it: endoscopic evacuation of intraventricular lesions using a flexible endoscope in combination with an angiographic catheter

BACKGROUND

In intraventricular surgery using a flexible endoscope, the lesion is usually aspirated via the working channel. However, the surgical view during aspiration is extremely poor because the objective lens is located adjacent to the working channel.

METHOD

To address this issue, we developed a novel surgical procedure using an angiographic catheter. In this procedure, the catheter is inserted into the working channel, and the lesion is aspirated through the catheter. Besides, continuous intraventricular irrigation is performed via the gap between the catheter and the working channel.

CONCLUSION

This procedure maintains a clear view during surgery and reduces complications.

A novel pulsed field ablation system using linear and spiral ablation catheters can create large and durable endocardial and epicardial ventricular lesions in vivo

BACKGROUND

We investigated the preclinical safety and efficacy of ventricular pulsed field ablation (PFA) using a family of novel, 6-/8-Fr, linear, and spiral PFA/mapping catheters (CRC EP, Inc).

METHODS

QRS-gated, bipolar PFA (>2.0 kV) was performed in 10 healthy swine. Altogether, 20 endocardial and epicardial right and left ventricular applications were delivered. The catheters were inserted through an 8.5-Fr steerable introducer. The intensity of skeletal muscle activation was quantified using an accelerometer. Lesions were assessed by pre- versus post-PFA electrogram analysis, pacing threshold, 3D voltage mapping, necropsy, and histology. The swine rete mirabile, liver and kidneys were examined for embolic events.

RESULTS

All applications were single-shot (56 ± 18 s) without catheter repositioning. Minimal microbubbling was observed without significant skeletal muscle stimulation (mean acceleration 0.05 m/s2) or ventricular tachyarrhythmias. There was significant reduction in post- versus pre-PFA electrogram amplitude (0.5 ± 0.2 mV versus 3.2 ± 0.9 mV, P < 0.001) with a marked increase in pacing threshold (>20 mA versus 7.5 ± 2.9 mA, P < 0.001). All lesions were large and durable up to 28 days, measuring 32 ± 5 mm (length), 27 ± 8 mm (width), and 8 ± 3 mm (depth) using the spiral catheters and 43 ± 1 mm (length), 7 ± 1 mm (width), and 8 ± 1 mm (depth) using the linear catheters. Despite higher waveform voltages and prolonged applications, no thermal effects were detected at necropsy/histology. Moreover, gross and microscopic examinations revealed no evidence of thromboembolism, vascular or collateral injury.

CONCLUSIONS

A novel, QRS-gated PFA system using linear and spiral PFA catheters is capable of creating large and durable ventricular lesions in vivo without significant microbubbling, ventricular arrhythmias or thromboembolism.

Poor Accuracy of Manually Derived Head Computed Tomography Parameters in Predicting Intracranial Hypertension After Nontraumatic Intracranial Hemorrhage

BACKGROUND

The utility of head computed tomography (CT) in predicting elevated intracranial pressure (ICP) is known to be limited in traumatic brain injury; however, few data exist in patients with spontaneous intracranial hemorrhage.

METHODS

We conducted a retrospective review of prospectively collected data in patients with nontraumatic intracranial hemorrhage (subarachnoid hemorrhage [SAH] or intraparenchymal hemorrhage [IPH]) who underwent external ventricular drain (EVD) placement. Head CT scans performed immediately prior to EVD placement were quantitatively reviewed for features suggestive of elevated ICP, including temporal horn diameter, bicaudate index, basal cistern effacement, midline shift, and global cerebral edema. The modified Fisher score (mFS), intraventricular hemorrhage score, and IPH volume were also measured, as applicable. We calculated the accuracy, positive predictive value (PPV), and negative predictive value (NPV) of these radiographic features for the coprimary outcomes of elevated ICP (> 20 mm Hg) at the time of EVD placement and at any time during the hospital stay. Multivariable backward stepwise logistic regression analysis was performed to identify significant radiographic factors associated with elevated ICP.

RESULTS

Of 608 patients with intracranial hemorrhages enrolled during the study time frame, 243 (40%) received an EVD and 165 (n = 107 SAH, n = 58 IPH) had a preplacement head CT scan available for rating. Elevated opening pressure and elevated ICP during hospitalization were recorded in 48 of 152 (29%) and 103 of 165 (62%), respectively. The presence of ≥ 1 radiographic feature had only 32% accuracy for identifying elevated opening pressure (PPV 30%, NPV 58%, area under the curve [AUC] 0.537, 95% asymptotic confidence interval [CI] 0.436-0.637, P = 0.466) and 59% accuracy for predicting elevated ICP during hospitalization (PPV 63%, NPV 40%, AUC 0.514, 95% asymptotic CI 0.391-0.638, P = 0.820). There was no significant association between the number of radiographic features and ICP elevation. Head CT scans without any features suggestive of elevated ICP occurred in 25 of 165 (15%) patients. However, 10 of 25 (40%) of these patients had elevated opening pressure, and 15 of 25 (60%) had elevated ICP during their hospital stay. In multivariable models, mFS (adjusted odds ratio [aOR] 1.36, 95% CI 1.10-1.68) and global cerebral edema (aOR 2.93, 95% CI 1.27-6.75) were significantly associated with elevated ICP; however, their accuracies were only 69% and 60%, respectively. All other individual radiographic features had accuracies between 38 and 58% for identifying intracranial hypertension.

CONCLUSIONS

More than 50% of patients with spontaneous intracranial hemorrhage without radiographic features suggestive of elevated ICP actually had ICP > 20 mm Hg during EVD placement or their hospital stay. Morphological head CT findings were only 32% and 59% accurate in identifying elevated opening pressure and ICP elevation during hospitalization, respectively.

Significant difference in cardiac ventricular dimensions when measured using two different standard methods

Cardiac ventricular dimensions measured at postmortem examination are used to assess whether there is hypertrophy of the heart chambers. However, there is no clear consensus on where these measurements should be taken. Some have proposed this should be measured at the mid-ventricular level, but others advocate it should be measured at a set distance (e.g. 20 mm) from the base of the heart. Twenty consecutive adult hearts were examined and showed the ventricular dimensions were significantly higher (mean: 5-15 mm, p < 0.01) when measured at a level 20 mm from the base of the heart compared to the mid-ventricular level. Of clinical significance is that in slightly less than half the cases, normal ventricular dimensions at mid ventricle level fell within the criteria considered pathological (> 40 mm) when measured at 20 mm from the base of the heart. In terms of actual ventricular dimensions, only the left ventricle diameter measured at 20 mm from the base of the heart correlated significantly (albeit moderately) with heart weight, suggesting it can be a predictor for cardiac hypertrophy.

Comparative analysis of the cardiac structure and transcriptome of scallop and snail, perspectives on heart chamber evolution

The evolution of a two-chambered heart, with an atrium and a ventricle, has improved heart function in both deuterostomes (vertebrates) and some protostomes (invertebrates). Although studies have examined the unique structure and function of these two chambers, molecular comparisons are few and limited to vertebrates. Here, we focus on the two-chambered protostome heart of the mollusks, offering data that may provide a better understanding of heart evolution. Specifically, we asked if the atrium and ventricle differ at the molecular level in the mollusk heart. To do so, we examined two very different species, the giant African land snail (Lissachatina fulica) and the relatively small, aquatic yesso scallop (Mizuhopecten yessoensis), with the assumption that if they exhibited commonality these similarities would likely reflect those across the phylum. We found that, although the hearts of these two species differed histologically, their cardiac gene function enrichments were similar, as revealed by transcriptomic analysis. Furthermore, the atrium and ventricle in each species had distinct gene function clusters, suggesting an evolutionary differentiation of cardiac chambers in mollusks. Finally, to explore the relationship between vertebrate and invertebrate two-chambered hearts, we compared our transcriptomic data with published data from the zebrafish, a well-studied vertebrate model with a two-chambered heart. Our analysis indicated a functional similarity of ventricular genes between the mollusks and the zebrafish, suggesting that the ventricle was differentiated to achieve the same functions in invertebrates and vertebrates. As the first such study on protostomes, our findings offered initial insights into how the two-chambered heart arose, including a possible understanding of its occurrence in both protostomes and deuterostomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00202-0.

Morphology of papillary muscles in the ventricles of heart - a review and meta-analysis

OBJECTIVE

To review the morphology of papillary muscles in both the ventricles of heart.

METHODS

The articles were collected from databases such as MEDLINE etc. using Google as the search engine. Keywords used were papillary muscle morphology, papillary muscle dimensions, papillary muscle blood supply, papillary muscle histology, papillary muscle development and papillary muscle biomechanical properties. Studies were included if they assessed the aforesaid features of papillary muscles. Thirty-four studies were included in the review. Meta-analysis was done for number of right and left ventricular papillary muscles and dimensions of right ventricular papillary muscles. The data obtained from these studies was synthesized, pooled and all analyses were performed using R Statistical Software (v4.1.2; R Core Team 2021) with R package meta version 5.5-0.

RESULTS

Marked difference existed between papillary muscles of right and left ventricles. In right ventricle, one anterior (76%), one posterior (38%) and one septal (30%) papillary muscle were most common. In left ventricle, one anterior (46%) and two posterior papillary muscles (26%) were most common. In both the ventricles, commonly observed gross appearances of papillary muscles were conical and flat-topped. Papillary muscles were lengthier in left ventricle than right ventricle. Anterior papillary muscle was 1.36cm long, 1.36cm broad and 0.64cm thick in right ventricle. It was the largest in both right and left ventricles.

CONCLUSION

The morphology and measurements of papillary muscles vary significantly. Thorough knowledge of these variations will help surgeons to determine appropriate surgical repair procedures for the valve and subvalvular apparatus.

Electrophysiological heterogeneity in large populations of rabbit ventricular cardiomyocytes

AIMS

Cardiac electrophysiological heterogeneity includes: (i) regional differences in action potential (AP) waveform, (ii) AP waveform differences in cells isolated from a single region, (iii) variability of the contribution of individual ion currents in cells with similar AP durations (APDs). The aim of this study is to assess intra-regional AP waveform differences, to quantify the contribution of specific ion channels to the APD via drug responses and to generate a population of mathematical models to investigate the mechanisms underlying heterogeneity in rabbit ventricular cells.

METHODS AND RESULTS

APD in ∼50 isolated cells from subregions of the LV free wall of rabbit hearts were measured using a voltage-sensitive dye. When stimulated at 2 Hz, average APD90 value in cells from the basal epicardial region was 254 ± 25 ms (mean ± standard deviation) in 17 hearts with a mean interquartile range (IQR) of 53 ± 17 ms. Endo-epicardial and apical-basal APD90 differences accounted for ∼10% of the IQR value. Highly variable changes in APD occurred after IK(r) or ICa(L) block that included a sub-population of cells (HR) with an exaggerated (hyper) response to IK(r) inhibition. A set of 4471 AP models matching the experimental APD90 distribution was generated from a larger population of models created by random variation of the maximum conductances (Gmax) of 8 key ion channels/exchangers/pumps. This set reproduced the pattern of cell-specific responses to ICa(L) and IK(r) block, including the HR sub-population. The models exhibited a wide range of Gmax values with constrained relationships linking ICa(L) with IK(r), ICl, INCX, and INaK.

CONCLUSION

Modelling the measured range of inter-cell APDs required a larger range of key Gmax values indicating that ventricular tissue has considerable inter-cell variation in channel/pump/exchanger activity. AP morphology is retained by relationships linking specific ionic conductances. These interrelationships are necessary for stable repolarization despite large inter-cell variation of individual conductances and this explains the variable sensitivity to ion channel block.

Zebrafish heart regeneration after coronary dysfunction-induced cardiac damage

Over the past 20 years, various zebrafish injury models demonstrated efficient heart regeneration after cardiac tissue loss. However, no established coronary vessel injury methods exist in the zebrafish model, despite coronary endothelial dysfunction occurring in most patients with acute coronary syndrome. This is due to difficulties performing surgery on small coronary vessels and a lack of genetic tools to precisely manipulate coronary cells in zebrafish. We determined that the Notch ligand gene deltaC regulatory sequences drive gene expression in zebrafish coronary endothelial cells, enabling us to overcome these obstacles. We created a deltaC fluorescent reporter line and visualized robust coronary growth during heart development and regeneration. Importantly, this reporter facilitated the visualization of coronary growth without an endocardial background. Moreover, we visualized robust coronary growth on the surface of juvenile hearts and regrowth in the wounded area of adult hearts ex vivo. With this approach, we observed growth inhibition by reported vascular growth antagonists of the VEGF, EGF and Notch signaling pathways. Furthermore, we established a coronary genetic ablation system and observed that severe coronary endothelial cell loss resulted in fish death, whereas fish survived mild coronary cell loss. Coronary cell depletion triggered regenerative responses, which resulted in the restoration of damaged cardiac tissues within several weeks. Overall, our work demonstrated the efficacy of using deltaC regulatory elements for high-resolution visualization of the coronary endothelium; screening small molecules for coronary growth effects; and revealed complete recovery in adult zebrafish after coronary-induced heart damage.

Ionic currents underlying different patterns of electrical activity in working cardiac myocytes of mammals and non-mammalian vertebrates

The orderly contraction of the vertebrate heart is determined by generation and propagation of cardiac action potentials (APs). APs are generated by the integrated activity of time- and voltage-dependent ionic channels which carry inward Na⁺ and Ca²⁺ currents, and outward K⁺ currents. This review compares atrial and ventricular APs and underlying ion currents between different taxa of vertebrates. We have collected literature data and attempted to find common electrophysiological features for two or more vertebrate groups, show differences between taxa and cardiac chambers, and indicate gaps in the existing data. Although electrical excitability of the heart in all vertebrates is based on the same superfamily of channels, there is a vast variability of AP waveforms between atrial and ventricular myocytes, between different species of the same vertebrate class and between endothermic and ectothermic animals. The wide variability of AP shapes is related to species-specific differences in animal size, heart rate, stage of ontogenetic development, excitation-contraction coupling, temperature and oxygen availability. Some of the differences between taxa are related to evolutionary development of genomes, which appear e.g. in the expression of different Na⁺ and K⁺ channel orthologues in cardiomyocytes of vertebrates. There is a wonderful variability of AP shapes and underlying ion currents with which electrical excitability of vertebrate heart can be generated depending on the intrinsic and extrinsic conditions of animal body. This multitude of ionic mechanisms provides excellent material for studying how the function of the vertebrate heart can adapt or acclimate to prevailing physiological and environmental conditions.

Adrenergic prolongation of action potential duration in rainbow trout myocardium via inhibition of the delayed rectifier potassium current, IKr

Catecholamines mediate the 'fight or flight' response in a wide variety of vertebrates. The endogenous catecholamine adrenaline increases heart rate and contractile strength to raise cardiac output. The increase in contractile force is driven in large part by an increase in myocyte Ca²⁺ influx on the L-type Ca current (I_CaL) during the cardiac action potential (AP). Here, we report a K⁺- based mechanism that prolongs AP duration (APD) in fish hearts following adrenergic stimulation. We show that adrenergic stimulation inhibits the delayed rectifier K⁺ current (I_Kr) in rainbow trout (Oncorhynchus mykiss) cardiomyocytes. This slows repolarization and prolongs APD which may contribute to positive inotropy following adrenergic stimulation in fish hearts. The endogenous ligand, adrenaline (1 μM), which activates both α- and β-ARs reduced maximal I_Kr tail current to 61.4 ± 3.9% of control in atrial and ventricular myocytes resulting in an APD prolongation of ~20% at both 50 and 90% repolarization. This effect was reproduced by the α-specific adrenergic agonist, phenylephrine (1 μM), but not the β-specific adrenergic agonist isoproterenol (1 μM). Adrenaline (1 μM) in the presence of β₁ and β₂-blockers (1 μM atenolol and 1 μM ICI-118551, respectively) also inhibited I_Kr. Thus, I_Kr suppression following α-adrenergic stimulation leads to APD prolongation in the rainbow trout heart. This is the first time this mechanism has been identified in fish and may act in unison with the well-known enhancement of I_CaL following adrenergic stimulation to prolong APD and increase cardiac inotropy.

Ventriculocholecystal Shunt as a Salvage Procedure in Shunt Dependent Hydrocephalic Children with Compromised Peritoneal Cavity

Multiple shunt revisions are a formidable challenge in neurosurgery, as the surgeon faces progressive difficulties in finding suitable distal sites for implantation. Gallbladder offers an alternative safe implantation site of distal catheter in case of repeated peritoneal failures. We describe two such cases done in our institute in this brief report. One case has long term functioning shunt, whist other had complications. Relevant literature is also briefly reviewed here.

Comparative and Functional Anatomy of the Ectothermic Sauropsid Heart

The heart development, form, and functional specializations of chelonians, squamates, crocodilians, and birds characterize how diverse structure and specializations arise from similar foundations. This review aims to summarize the morphologic diversity of sauropsid hearts and present it in an integrative functional and phylogenetic context. Besides the detailed morphologic descriptions, the integrative view of function, evolution, and development will aid understanding of the surprising diversity of sauropsid hearts. This integrated perspective is a foundation that strengthens appreciation that the sauropsid hearts are the outcome of biological evolution; disease often is linked to arising mismatch between adaptations and modern environments.

Moving silicone oil particles in the ventricle: a case report and updated review

Background

The movement of intraventricular silicone oil observed in the supine position is extremely rare. Herein, we describe a patient who presented with dynamically moving silicone oil particles in the ventricle when changing position and provide an updated review of this phenomenon.

Case presentation

We report a case of a 70-year-old woman who presented with intraventricular hyperdensities that were occasionally found on brain computed tomography (CT). Initial nonenhanced brain CT demonstrated nondependent hyperdensities in the bilateral anterior horns of the lateral ventricles, the third ventricle, and the right suprasellar cistern, mimicking an intraventricular hemorrhage. Further brain magnetic resonance imaging (MRI) in the supine position revealed abnormal signals in the bilateral anterior horns of the lateral ventricles, the posterior horn of the right lateral ventricle, the third ventricle, the right suprasellar cistern, and the bilateral eyeballs, with isosignal intensities surrounded by low-signal chemical shift artifacts on T₁-weighted imaging and variable signals (hypo- or hyperintensity) on T₂-weighted imaging. The lesion in the anterior horn of the right ventricle largely moved to the posterior horn of the ipsilateral ventricle. The final craniocervical CT angiography showed that the lesion in the posterior horn had moved back to the anterior horn of the right lateral ventricle. These features were consistent with intraventricular silicone oil migration. The final spinal MRI did not demonstrate a migration of silicone oil into the spinal subarachnoid space.

Discussion and conclusions

This case report describes a dynamic process of silicone oil displacement in the supine position and provides a comprehensive imaging presentation. The moving pattern and a characteristic chemical shift artifact on MRI are key to the diagnosis and may help prevent unnecessary examinations or intervention.

Quantitative brain MRI morphology in severe and attenuated forms of mucopolysaccharidosis type I

OBJECTIVE

To assess our hypothesis that brain macrostructure is different in individuals with mucopolysaccharidosis type I (MPS I) and healthy controls (HC), we conducted a comprehensive multicenter study using a uniform quantitative magnetic resonance imaging (qMRI) protocol, with analyses that account for the effects of disease phenotype, age, and cognition.

METHODS

Brain MRIs in 23 individuals with attenuated (MPS IA) and 38 with severe MPS I (MPS IH), aged 4-25 years, enrolled under the study protocol NCT01870375, were compared to 98 healthy controls.

RESULTS

Cortical and subcortical gray matter, white matter, corpus callosum, ventricular and choroid plexus volumes in MPS I significantly differed from HC. Thicker cortex, lower white matter and corpus callosum volumes were already present at the youngest MPS I participants aged 4-5 years. Age-related differences were observed in both MPS I groups, but most markedly in MPS IH, particularly in cortical gray matter metrics. IQ scores were inversely associated with ventricular volume in both MPS I groups and were positively associated with cortical thickness only in MPS IA.

CONCLUSIONS

Quantitatively-derived MRI measures distinguished MPS I participants from HC as well as severe from attenuated forms. Age-related neurodevelopmental trajectories in both MPS I forms differed from HC. The extent to which brain structure is altered by disease, potentially spared by treatment, and how it relates to neurocognitive dysfunction needs further exploration.

FRESH 3D Bioprinting a Ventricle-like Cardiac Construct Using Human Stem Cell-Derived Cardiomyocytes

Here we describe a method to engineer a contractile ventricle-like chamber composed of human stem cell-derived cardiomyocytes using freeform reversible embedding of suspended hydrogels (FRESH) 3D bioprinting. To do this, we print a support structure using a collagen type I ink and a cellular component using a high-density cell ink supplemented with fibrinogen. The gelation of the collagen and the fibrinogen into fibrin is initiated by pH change and enzymatic crosslinking, respectively. Fabrication of the ventricle-like chamber is completed in three distinct phases: (i) materials preparation, (ii) bioprinting, and (iii) tissue maturation. In this protocol, we describe the method to print the construct from a high-density cell ink composed of human stem cell-derived cardiomyocytes and primary fibroblasts (~300 × 10⁶ cells/mL) using our open-source dual-extruder bioprinter. Additional details are provided on FRESH support preparation, bioink preparation, dual-extruder needle alignment, print parameter selection, and post-processing. This protocol can also be adapted by altering the 3D model design, cell concentration, or cell type to FRESH 3D bioprint other cardiac tissue constructs.

The effects of cumulative antipsychotic dose on brain structures in patients with schizophrenia: Observational study of multiple CT scans over a long-term clinical course

Multiple lines of evidence indicate that antipsychotic agents could affect brain structures of schizophrenia patients. However, the effect of antipsychotic dosage or type on brain structure is uncertain. The present study retrospectively analyzed brain computed tomography (CT) images from a psychiatric hospital to examine the relationship between cumulative dose of antipsychotics and brain volume reduction in schizophrenia patients. A total of 43 patients with repeated relapse episode of psychosis were included and CT scans that were performed an average of 3.2 times per patient during nearly 13 years of follow-up were analyzed. The results revealed significant positive relationships of expansion of cerebrospinal fluid space with cumulative dosage of all antipsychotics and that of typical antipsychotics. Patients treated with antipsychotics including typical antipsychotics exhibited a greater volume reduction compared to patients treated with only atypical antipsychotics. The present study was one of the longest longitudinal studies examining the effects of antipsychotics on brain volume in schizophrenia patients. These results suggest a relation between cumulative lifetime antipsychotic dosage and progressive brain volume reduction in patients with schizophrenia. However, the effects of specific agent on brain structure are still uncertain, and more detailed analysis is needed.

Design and Production of Heart Chamber-Specific AAV9 Vectors

Adeno-associated virus serotype 9 (AAV9) is often used in heart research involving gene delivery due to its cardiotropism, high transduction efficiency, and little to no pathogenicity, making it highly applicable for gene manipulation, in vivo. However, current AAV9 technology is limited by the lack of strains that can selectively express and elucidate gene function in an atrial- and ventricular-specific manner. In fact, study of gene function in cardiac atria has been limited due to the lack of an appropriate tool to study atrial gene expression in vivo, hindering progress in the study of atrial-specific diseases such as atrial fibrillation, the most common cardiac arrhythmia in the USA.This chapter describes the method for the design and production of such chamber-specific AAV9 vectors, with the use of Nppa and Myl2 promoters to enhance atrial- and ventricular-specific expression. While several gene promoter candidates were considered and tested, Nppa and Myl2 were selected for use here because of their clearly defined regulatory elements that confer cardiac chamber-specific expression. Accordingly, Nppa (-425/+25) and Myl2 (-226/+36) promoter fragments are inserted into AAV9 vectors. The atrial- and ventricular-specific expression conferred by these new recombinant AAV9 was confirmed in a double-fluorescent Cre-dependent reporter mouse model. At only 450 and 262 base pairs of Nppa and Myl2 promoters, respectively, these AAV9 that drive chamber-specific AAV9 transgene expression address two major limitations of AAV9 technology, i.e., achieving chamber-specificity while maximizing space in the AAV genome for insertion of larger transgenes.

Infant Ross-Konno, Endocardial Fibroelastosis Resection and Mitral Valve Repair

Optimal management of critical aortic stenosis (AS) in infants depends on the left ventricle's (LV's) ability to maintain adequate output. Determining feasibility of biventricular repair may be difficult, particularly in those with mitral disease, endocardial fibroelastosis (EFE), multi-level obstruction, and uncertain physiologic capacity. We report a case of a three-month-old with critical AS, severely reduced LV function, EFE, and moderate mitral regurgitation (MR), who underwent a Ross-Konno procedure with concomitant EFE resection and mitral valve repair. Although the technical sequence is challenging, definitive surgery completely relieved multi-level obstruction and MR with markedly improved LV function.

Exercise-induced irregular right heart flow dynamics in adolescents and young adults born preterm

BACKGROUND

Preterm birth has been linked to an elevated risk of heart failure and cardiopulmonary disease later in life. With improved neonatal care and survival, most infants born preterm are now reaching adulthood. In this study, we used 4D flow cardiovascular magnetic resonance (CMR) coupled with an exercise challenge to assess the impact of preterm birth on right heart flow dynamics in otherwise healthy adolescents and young adults who were born preterm.

METHODS

Eleven young adults and 17 adolescents born preterm (< 32 weeks of gestation and < 1500 g birth weight) were compared to 11 young adult and 18 adolescent age-matched controls born at term. Stroke volume, cardiac output, and flow in the main pulmonary artery were quantified with 4D flow CMR. Kinetic energy and vorticity were measured in the right ventricle. All parameters were measured at rest and during exercise at a power corresponding to 70% VO2max for each subject. Multivariate linear regression was used to perform age-adjusted term-preterm comparisons.

RESULTS

With exercise, stroke volume increased 10 ± 21% in term controls and decreased 4 ± 18% in preterm born subjects (p = 0.007). This resulted in significantly reduced capacity to increase cardiac output in response to exercise stress for the preterm group (58 ± 26% increase in controls, 36 ± 27% increase in preterm, p = 0.004). Elevated kinetic energy (KEterm = 71 ± 22 nJ, KEpreterm = 87 ± 38 nJ, p = 0.03) and vorticity (ωterm = 79 ± 16 s-1, ωpreterm = 94 ± 32 s-1, p = 0.01) during diastole in the right ventricle (RV) suggested altered RV flow dynamics in the preterm subjects. Streamline visualizations showed altered structure to the diastolic filling vortices in those born preterm.

CONCLUSIONS

For the participants examined here, preterm birth appeared to result in altered right-heart flow dynamics as early as adolescence, especially during diastole. Future studies should evaluate whether the altered dynamics identified here evolves into cardiopulmonary disease later in life. Trial registration None.

N-methyl-D-aspartate receptor antibody and the choroid plexus in schizophrenia patients with tardive dyskinesia

BACKGROUND

Immune disturbance has been postulated to be one of the mechanisms underlying the pathogenesis of tardive dyskinesia (TD). Recently, the role of autoimmune abnormality in TD has been increasingly recognized. Autoantibodies against neuronal N-methyl-D-aspartate receptor (NMDAR) may be cross-reactive in the brain in neuropsychiatric disorders, and the choroid plexus (CP) is a crucial immune barrier in the central nervous system (CNS). We supposed that NMDAR antibodies might underlie the pathophysiological process of TD through the mediation of CP.

METHODS

Serum NMDAR antibody levels were assessed by enzyme-linked immunosorbent assay, CP and ventricle volumes were assessed by magnetic resonance imaging in schizophrenia patients with TD (n = 61), without TD (NTD, n = 61), and in healthy controls (n = 74). Psychopathology and TD severity were assessed by the Positive and Negative Syndrome Scale and Abnormal Involuntary Movement Scale (AIMS).

RESULTS

NMDAR antibody levels were significantly higher, CP volumes were larger in the TD group than in the NTD group (p = 0.022; p = 0.019, respectively). In the TD group, higher NMDAR antibody level was correlated with larger CP volume (β = 0.406, p = 0.002). An elevated NMDAR antibody level and enlarged CP volume were correlated with orofacial AIMS score (β = 0.331, p = 0.011; β = 0.459, p = 3.34 × 10^-4, respectively). In a mediation model, the effect of NMDAR antibody level on the orofacial AIMS score was mediated by the CP volume (indirect effect: β = 0.08, 95% confidence interval = 0.002-0.225; direct effect: β = 0.14, p = 0.154).

CONCLUSIONS

Our findings highlight a potential NMDAR antibody-associated mechanism in orofacial TD, which may be mediated by increased CP volume.

Cerebrospinal fluid may flow out from the brain through the frontal skull base and choroid plexus: a gold colloid and cadaverine injection study in mouse fetus

PURPOSE

It has been commonly accepted for a long time that the cerebrospinal fluid (CSF) drains into arachnoid granulations from the subarachnoid space to the dural venous sinus unidirectionally. However, recently, periventricular capillaries and lymphatic concepts have been introduced. The CSF moves along the perivascular space and drains into the capillary vessels or meningeal lymphatic tissues. CSF is involved in removing brain waste out of the brain. In this study, we investigated the outflow mechanism of substances in the CSF from the brain.

METHODS

We investigated the movement of CSF by injection of gold colloid conjugates (2, 40, and 200 nm) into the lateral ventricles of mouse fetuses and evaluated the deposition by silver stain with tissue transparency and electron microcopy. Cadaverine was also injected into the lateral ventricle to determine its movement tract.

RESULTS

The gold particle deposition was mainly observed in the frontal skull base. Electron microscopic study showed that the gold particle deposition was observed on the choroid plexus and ependyma in the lateral ventricle and also red blood cells in the heart and liver. Two-nanometer particles were exclusively observed in the liver. Cadaverine injection study demonstrated that cadaverine was observed at the extracranial frontal skull base, choroid plexus, ependymal surface, and perivascular area in the brain white matter.

CONCLUSION

The particles in the CSF were shown to move from the brain to the frontal skull base and also into the blood stream through the choroid plexus in the fetus. The outflow of particles in the CSF may be regulated by molecular size. This new information will contribute to the prevention of brain degeneration due to brain waste deposition.

Effect of atrial artificial electrical stimulation on depolarization and repolarization and hemodynamics of the heart ventricle in rainbow trout Oncorhynchus mykiss

The spatial-temporal organization of the activation, repolarization and hemodynamics of the heart ventricle in rainbow trout, Oncorhynchus mykiss, adapted to a temperature of 5-7 °C, were studied from the normal sinus rhythm (21.6 ± 4.9 bpm) to the highest possible heart rhythm (HR) (60 bpm), during which deterioration of the contractile activity of the myocardium occurred. Regardless of the HR, the main pattern of excitation of the heart ventricle was the movement of the depolarization wave from the dorsal areas of the base in the base-apical and ventral directions with the capture of the entire thickness of the walls, with a slight difference in the time of activation of the subendocardium compared to the subepicardium. The increase in HR above the sinus rhythm caused significant shortening of local repolarization durations in all areas and layers (endocardial, intramural and subepicardial) of the heart ventricle. Changes in local durations of repolarization led to an increase in the heterogeneity of repolarization of the ventricular myocardium; as a result, a deterioration of its contractility was observed. In relation to the sinus rhythm, the maximal systolic pressure in the heart ventricle decreased, the diastolic and end-diastolic pressure increased, and the maximum rates of pressure rise and fall decreased. In rainbow trout adapted to a temperature of 5-7 °C at sinus rhythm, the pumping function of the heart was probably within the upper limit of the physiological norm, and a further increase in the heart rate led to a decline in myocardial contractility.

Endocardial ventricular pulsed field ablation: a proof-of-concept preclinical evaluation

Aims

Pulsed field ablation (PFA) is a novel, non-thermal modality that selectively ablates myocardium with ultra-short electrical impulses while sparing collateral tissues. In a proof-of-concept study, the safety and feasibility of ventricular PFA were assessed using a prototype steerable, endocardial catheter.

Methods and results

Under general anaesthesia, the left and right ventricles of four healthy swine were ablated using the 12-Fr deflectable PFA catheter and a deflectable sheath guided by electroanatomic mapping. Using the study catheter, electrograms were recorded for each site and pre-ablation and post-ablation pacing thresholds (at 2.0 ms pulse width) were recorded in two of four animals. After euthanasia at 35.5 days, the hearts were submitted for histology. The PFA applications (n = 39) resulted in significant electrogram reduction without ventricular arrhythmias. In ablation sites where it was measured, the pacing thresholds increased by >16.8 mA in the right ventricle (3 sites) and >16.1 mA in the left ventricle (7 sites), with non-capture at maximum amplitude (20 mA) observable in 8 of 10 sites. Gross measurements, available for 28 of 30 ablation sites, revealed average lesion dimensions to be 6.5 ± 1.7 mm deep by 22.6 ± 4.1 mm wide, with a maximum depth and width of 9.4 mm and 28.6 mm, respectively. In the PFA lesions, fibrous tissue homogeneously replaced myocytes with a narrow zone of surrounding myocytolysis and no overlying thrombus. When present, nerve fascicles and vasculature were preserved within surrounding fibrosis.

Conclusion

We demonstrate that endocardial PFA can be focally delivered using this prototype catheter to create homogeneous, myocardium-specific lesions.

Endoscopic resection of a low-grade ependymoma of the pineal region

Background

Full endoscopic resection of solid brain tumors represents a challenge for neurosurgeons. This can be achieved with modern technology and advanced surgical tools.

Case Description

A 23-years-old male was referred to our unit with raised intracranial pressure. Head computed tomography and magnetic resonance imaging (MRI) revealed obstructive hydrocephalus and a third ventricle lesion. Endoscopic third ventriculostomy and biopsy were performed, a left frontal external ventricular drain was left in place. A second-look surgery for endoscopic removal was planned. Decision to proceed with an endoscopic removal was supported by the following characteristics found during the first surgery: tumor exophytic, soft texture, scarce vascularity, and low-grade appearance. A rescue strategy for microscopic resection via transcallosal approach was decided. A straight trajectory to the tumor was planned with navigation. A further anterior left frontal burr-hole was performed, and the ventricular system was entered via the left frontal horn. Resection was carried out alternating laser for hemostasis and cutting, endoscopic ultrasonic aspirator, and endoscopic forceps for piecemeal resection. Laser hemostasis and cutting (1 Watt power at tip, continuous wave mode) were useful at the ventricular wall-tumor interface. Relevant landmarks guided the approach and the resection (foramen of Monro, mammillary bodies, aqueduct, pineal and suprapineal recess, and posterior commissure). The surgery was carried uneventfully. Histopathology confirmed a lowgrade ependymoma. Post-operative MRI showed residual tumor within the lower aqueduct. At 3 years follow-up, residual tumor is stable.

Conclusion

In selected cases, endoscopic resection for third ventricular tumors is feasible and safe, and represents a valid alternative to microsurgical approaches.

Study of correlation between 2D echocardiographic assessment of right ventricle and outcome of acute heart failure patients

Background

Hospital length of stay (LOS) is a key determinant of heart failure hospitalization costs and performance of medical care quality. Right ventricular (RV) dysfunction predicted poor outcome in patients with acute heart failure (AHF).

Aim

To study the effect of right ventricular function on length of hospital stay as a predictor in patients with acute heart failure.

Methods

A prospective cohort study was conducted in Cardiology Care Units (CCUs) in Zagazig University Hospital and Shark El Madina Hospital from September 2019 to February 2020, we included in this study 99 patients admitted with AHF. Clinical data and baseline RV function assessed by tricuspid annular plane systolic excursion (TAPSE) and S' velocity were collected. Clinical comorbidities including worsening renal function (WRF) were monitored during hospitalization. The primary outcome was hospital LOS.

Results

There was statistically significant correlation between WRF, right ventricular systolic dysfunction identified by TAPSE<16 mm and S' <9.5 cm/s and poor outcome in patients with acute heart failure including prolonged LOS.

Conclusion

Right ventricular (RV) systolic dysfunction as assessed by TAPSE and S' velocity and diastolic dysfunction were independent predictors of longer LOS in AHF patients. WRF had high prevalence among patients with AHF and associated with poor outcome in AHF patients and prolonged LOS.

Isolation and culture of adult murine cardiac atrial and ventricular fibroblasts and myofibroblasts

Cardiac fibroblasts play a critical role in extracellular matrix homeostasis, wound healing, and cardiac interstitial fibrosis: the latter being a pathophysiological response to a chronic increase in afterload. Using a standard protocol to isolate cardiac fibroblasts and maintain them in their quiescent phenotype in vitro will enable a better understanding of cardiac fibroblast biology and their role in the response to profibrotic stimuli. Here, we describe an enzymatic method for isolating cardiac fibroblasts. The resulting cells are maintained on either a collagen-coated hydrogel-bound polystyrene (compliant) substrate or standard polystyrene culture dishes (non-compliant) to obtain quiescent fibroblasts and activated fibroblasts (myofibroblasts), respectively. Fibroblasts maintained on a non-compliant substrate developed a myofibroblast phenotype, in which the αSMA immunoreactivity was markedly elevated and incorporated into the stress fibers. In contrast, ventricular and atrial fibroblasts retain their quiescent phenotype for up to 3 passages when maintained on a compliant substrate. Hence, the methodology described herein provides a simple and reproducible way to isolate adult murine atrial and ventricular cardiac fibroblasts from a single animal and, by selecting a substrate with the appropriate compliance, examine the mediators of fibroblast activation or inactivation.

Retinoic acid signaling restricts the size of the first heart field within the anterior lateral plate mesoderm

Retinoic acid (RA) signaling is required to restrict heart size through limiting the posterior boundary of the vertebrate cardiac progenitor field within the anterior lateral plate mesoderm (ALPM). However, we still do not fully understand how different cardiac progenitor populations that contribute to the developing heart, including earlier-differentiating first heart field (FHF), later-differentiating second heart field (SHF), and neural crest-derived progenitors, are each affected in RA-deficient embryos. Here, we quantified the number of cardiac progenitors and differentiating cardiomyocytes (CMs) in RA-deficient zebrafish embryos. While Nkx2.5+ cells were increased overall in the nascent hearts of RA-deficient embryos, unexpectedly, we found that the major effect within this population was a significant expansion in the number of differentiating FHF CMs. In contrast to the expansion of the FHF, there was a progressive decrease in SHF progenitors at the arterial pole as the heart tube elongated. Temporal differentiation assays and immunostaining in RA-deficient embryos showed that the outflow tracts (OFTs) of the hearts were significantly smaller, containing fewer differentiated SHF-derived ventricular CMs and a complete absence of SHF-derived smooth muscle at later stages. At the venous pole of the heart, pacemaker cells of the sinoatrial node also failed to differentiate in RA-deficient embryos. Interestingly, genetic lineage tracing showed that the number of neural-crest derived CMs was not altered within the enlarged hearts of RA-deficient zebrafish embryos. Altogether, our data show that the enlarged hearts in RA-deficient zebrafish embryos are comprised of an expansion in earlier differentiating FHF-derived CMs coupled with a progressive depletion of the SHF, suggesting RA signaling determines the relative ratios of earlier- and later-differentiation cardiac progenitors within an expanded cardiac progenitor pool.

Diagnosis and Therapeutic Management of Ventricular Gangliogliomas: An Illustrated Review

BACKGROUND

Gangliogliomas (GGs) are extremely rare benign neoplasms frequently located within the temporal lobe that usually present with seizures. GGs growing predominantly within the ventricular system (VGGs) are even more infrequent, so definite conclusions concerning their diagnosis and therapeutic management are lacking.

METHODS

A retrospective review of case reports of VGGs was performed from the introduction of modern imaging techniques, including 4 new illustrative cases treated in our department.

RESULTS

Thirty-four cases were collected. Ages ranged from 10 to 71 years (mean, 26.62 years), and 55.9% were male. Most patients developed symptoms related to high intracranial pressure. The lateral ventricles were predominantly involved (58.8%). Obstructive hydrocephalus was observed in 54.5% of patients. Cystic degeneration and calcification were frequently observed. Surgical treatment was carried out in all cases. Morbidity and mortality were 17.6% and 2.9%, respectively. Gross total tumor resection was achieved in 64.5% of patients. Four patients experienced tumor dissemination along the neural axis. More than 90% of patients maintained a good functional status at last follow-up.

CONCLUSIONS

Despite their low incidence, a diagnosis of VGGs should be considered in young male adults who progressively develop intracranial hypertension, caused by a ventricular mass showing signs of cystic degeneration and calcification. Maximal and safe surgical resection represents the gold standard for the treatment of symptomatic VGGs, although total removal is frequently precluded by difficulties in defining appropriate tumor boundaries. Adjuvant radiotherapy should be considered if an incomplete resection was carried out, especially in World Health Organization grade III neoplasms.

Assessing Pressure-Volume Relationship in Developing Heart of Zebrafish In-Vivo

During embryogenesis, the developing heart transforms from a linear peristaltic tube into a multi-chambered pulsatile pump with blood flow-regulating valves. In this work, we report how hemodynamic parameters evolve during the heart's development, leading to its rhythmic pumping and blood flow regulation as a functioning organ. We measured the time course of intra-ventricular pressure from zebrafish embryos at 3, 4, and 5 days post fertilization (dpf) using the servo null method. We also measured the ventricular volume and monitored the opening/closing activity of the AV and VB valves using 4D selective plane illumination microscopy (SPIM). Our results revealed significant increases in peak systolic pressure, stroke volume and work, cardiac output, and power generation, and a total peripheral resistance decrease from zebrafish at 4, 5 dpf versus 3 dpf. These data illustrate that the early-stage zebrafish heart's increasing efficiency is synchronous with the expected changes in valve development, chamber morphology and increasing vascular network complexity. Such physiological measurements in tractable laboratory model organisms are critical for understanding how gene variants may affect phenotype. As the zebrafish emerges as a leading biomedical model organism, the ability to effectively measure its physiology is critical to its translational relevance.

Left and right ventricular longitudinal strains are associated with poor outcome in COVID-19: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to assess whether ventricular longitudinal strain can be used as a prognostication tool in patients with coronavirus disease 2019 (COVID-19).

METHODS

Systematic literature searches of PubMed, Embase, and EuropePMC databases were performed on 16 November 2020. Left ventricular global longitudinal strain (LV-GLS) refers to LV contraction measurement using the speckle tracking-based method refers to the mean of strain values of the RV free wall (three segments) measured using echocardiography. The main outcome was poor outcome, defined as a composite of mortality and severe COVID-19.

RESULTS

Seven studies comprising of 612 patients were included in meta-analysis. Six studies have mortality as their outcome, and 1 study has severity as their outcome. Patients with poor outcome have lower LV-GLS (SMD 1.15 (0.57, 1.72), p < 0.001; I2 70.4%). Each 1% decrease in LV-GLS was associated with 1.4x increased risk of poor outcome (OR 1.37 (1.12, 1.67), p = 0.002; I2 48.8%). Patients with poor outcome have lower RV-LS (SMD 1.18 (0.91, 1.45), p < 0.001; I2 0%). Each 1% decrease in RV-LS was associated with 1.3x increased risk of poor outcome (OR 1.25 (1.15, 1.35), p < 0.001; I2 11.8%). Subgroup analysis showed that for every 1% decrease in LV-GLS and RV-LS is increased mortality with OR of 1.30 (1.12, 1.50) and OR of 1.24 (1.14, 1.35), respectively.

CONCLUSION

This study shows that lower LV-GLS and RV-LS measurements were associated with poor outcome in patients with COVID-19.

TRIAL REGISTRATION

PROSPERO CRD42020221144.

Increase in Ventricle Size and the Evolution of White Matter Changes on Serial Imaging in Critically Ill Patients with COVID-19

BACKGROUND

Evolution of brain magnetic resonance imaging (MRI) findings in critically ill patients with coronavirus disease 2019 (COVID-19) is unknown.

METHODS

We retrospectively reviewed 4530 critically ill patients with COVID-19 admitted to three tertiary care hospitals in New York City from March 1 to June 30, 2020 to identify patients who had more than one brain MRI. We reviewed the initial and final MRI for each patient to (1) measure the percent change in the bicaudate index and third ventricular diameter and (2) evaluate changes in the presence and severity of white matter changes.

RESULTS

Twenty-one patients had two MRIs separated by a median of 22 [Interquartile range (IQR) 14-30] days. Ventricle size increased for 15 patients (71%) between scans [median bicaudate index 0.16 (IQR 0.126-0.181) initially and 0.167 (IQR 0.138-0.203) on final imaging (p < 0.001); median third ventricular diameter 6.9 mm (IQR 5.4-10.3) initially and 7.2 mm (IQR 6.4-10.8) on final imaging (p < 0.001)]. Every patient had white matter changes on the initial and final MRI; between images, they worsened for seven patients (33%) and improved for three (14%).

CONCLUSIONS

On serial imaging of critically ill patients with COVID-19, ventricle size frequently increased over several weeks. White matter changes were often unchanged, but in some cases they worsened or improved, demonstrating there is likely a spectrum of pathophysiological processes responsible for these changes.

Effects of hypoxic acclimation on contractile properties of the spongy and compact ventricular myocardium of steelhead trout (Oncorhynchus mykiss)

The trout ventricle has an outer compact layer supplied with well-oxygenated arterial blood from the coronary circulation, and an inner spongy myocardium supplied with oxygen poor venous blood. It was hypothesized that: (1) the spongy myocardium of steelhead trout (Oncorhynchus mykiss), given its routine exposure to low partial pressures of oxygen (PO₂), would be better able to maintain contractile performance (work) when exposed to acute hypoxia (100 to 10% air saturation) relative to the compact myocardium, and would show little benefit from hypoxic acclimation; and (2) the compact myocardium from hypoxia-acclimated (40% air saturation) fish would be better able to maintain work during acute exposure to hypoxia relative to normoxia-acclimated individuals. Consistent with our expectations, when PO₂ was acutely lowered, net work from the compact myocardium of normoxia-acclimated fish declined more (by ~ 73%) than the spongy myocardium (~ 50%), and more than the compact myocardium of hypoxia-acclimated fish (~ 55%), and hypoxic acclimation did not benefit the spongy myocardium in the face of reduced PO₂. Further, while hypoxic acclimation resulted in a 25% (but not significant) decrease in net work of the spongy myocardium, the performance of the compact myocardium almost doubled. This research suggests that, in contrast to the spongy myocardium, performance of the compact myocardium is improved by hypoxic acclimation; and supports previous research suggesting that the decreased contractile performance of the myocardium upon exposure to lowered PO₂ may be adaptive and mediated by mechanisms within the muscle itself.

Neuroimaging diagnosis of intraventricular Central neurocytoma

OBJECTIVE

To study the CT and MRI imaging manifestations of central and intraventricular central neurocytoma in the ventricle.

METHODS

In this paper, 39 patients with central nervous cell tumour treated in our hospital from August 2015 to June 2018 were selected. All patients were performed plain CT scans using GE Highspeed CT; GE signa Twin speed 1.5 T superconducting magnet Resonance scanners were used to perform MRI plain scans on all patients. Observe the specific location, size, and morphology of tumours in the supra- and sub-ventricular ventricles of 39 central nervous cell tumour patients, and compare the performance of CT examination with the performance of MRI examination.

RESULTS

Of the 39 patients with central neurocytoma, 13 were in the right lateral ventricle, 9 were in the left lateral ventricle, 11 patients had tumours in both lateral ventricles, and 6 patients had bilateral ventricles and bilateral ventricles. There were tumours in the third ventricle; 39 patients had an average tumour size of 52 mm; 36 patients had irregular lobes, and 3 patients had blurred tumour boundaries; some tumours had different degrees of calcification.

CONCLUSIONS

The location and characteristics of the imaging manifestations of central nervous cell tumours are typical. Both CT scans and MRI scans can effectively detect central neuroblastomas, and MRI imaging examinations can effectively improve the diagnosis accuracy of tumour is better than that of CT.

Relationship between oxygen consumption and neuronal activity in a defined neural circuit

BACKGROUND

Neuronal computations related to sensory and motor activity along with the maintenance of spike discharge, synaptic transmission, and associated housekeeping are energetically demanding. The most efficient metabolic process to provide large amounts of energy equivalents is oxidative phosphorylation and thus dependent on O2 consumption. Therefore, O2 levels in the brain are a critical parameter that influences neuronal function. Measurements of O2 consumption have been used to estimate the cost of neuronal activity; however, exploring these metabolic relationships in vivo and under defined experimental conditions has been limited by technical challenges.

RESULTS

We used isolated preparations of Xenopus laevis tadpoles to perform a quantitative analysis of O2 levels in the brain under in vivo-like conditions. We measured O2 concentrations in the hindbrain in relation to the spike discharge of the superior oblique eye muscle-innervating trochlear nerve as proxy for central nervous activity. In air-saturated bath Ringer solution, O2 levels in the fourth ventricle and adjacent, functionally intact hindbrain were close to zero. Inhibition of mitochondrial activity with potassium cyanide or fixation of the tissue with ethanol raised the ventricular O2 concentration to bath levels, indicating that the brain tissue consumed the available O2. Gradually increasing oxygenation of the Ringer solution caused a concurrent increase of ventricular O2 concentrations. Blocking spike discharge with the local anesthetics tricaine methanesulfonate diminished the O2 consumption by ~ 50%, illustrating the substantial O2 amount related to neuronal activity. In contrast, episodes of spontaneous trochlear nerve spike bursts were accompanied by transient increases of the O2 consumption with parameters that correlated with burst magnitude and duration.

CONCLUSIONS

Controlled experimental manipulations of both the O2 level as well as the neuronal activity under in vivo-like conditions allowed to quantitatively relate spike discharge magnitudes in a particular neuronal circuitry with the O2 consumption in this area. Moreover, the possibility to distinctly manipulate various functional parameters will yield more insight in the coupling between metabolic and neuronal activity. Thus, apart from providing quantitative empiric evidence for the link between physiologically relevant spontaneous spike discharge in the brain and O2-dependent metabolism, isolated amphibian preparations are promising model systems to further dissociate the O2 dynamics in relation to neuronal computations.

Telovelar surgical approach

Surgical access to lesions in the fourth ventricle may be achieved utilizing transvermian or transtelovelar trajectories. We performed a search of the PubMed database for studies describing the microsurgical details and evaluating the clinical utility of the telovelar surgical approach. The telovelar approach has proven to be a safe, effective, and versatile alternative to the transvermian approach. The operative strategy utilizes midline suboccipital craniotomy without or with C1 laminectomy, followed by cerebellar hemispheric and tonsillar retraction, and wide durotomy. Access is generously provided to the fourth ventricle from calamus scriptorius to Sylvian aqueduct and foramen Luschkae bilaterally. Anatomic dissection studies evaluating and comparing the relative benefits of the operative exposure offered by these approaches have demonstrated improved access to the lateral recess gained by the telovelar trajectory and facilitated exposure of rostral reaches of the fourth ventricle by the vermian trajectory. In general, operative exposure may be significantly improved with tonsillar retraction or resection, bilateral telovelar opening, and performing C1 laminectomy in order to improve access to the rostral fourth ventricle, which may be variably combined depending on location of pathology. Cerebellar mutism, a high incidence of which occurs with vermian approaches, is not commonly observed with use of the telovelar trajectory, though injury to the dentate nuclei may precipitate this syndrome. Deficits incurred with the vermian approach may include cerebellar mutism, dysequilibrium, truncal ataxia, posterior fossa syndrome, cranial nucleopathies and nerve palsies, and vascular injury to the posterior inferior cerebellar artery. The telovelar surgical approach has proven a safe and useful alternative to the transvermian trajectory. A significantly lower incidence of cerebellar mutism and cerebellogenic deficits represents the principal advantage of the telovelar approach. Further studies are necessary in order to prospectively evaluate and compare extents of resection, morbidity, and mortality utilizing the telovelar versus vermian approaches for microsurgically resecting fourth ventricular tumors.

Histological study on the heart ventricle of Egyptian bovines (Bos aegyptiacus)

Background:

The heart ventricles have thicker walls than atrium as they pump blood through blood vessels into all body organs.

Aim:

This study aimed to describe the histological changes of the heart ventricles in Egyptian bovine (Bos aegyptiacus) with special reference to Purkinje fibers.

Methods:

A total of 10 male Egyptian bovines of 1–10 years old were divided into three groups according to age; immature, mature, and adult animals.

Results:

The histological sections from all examined animals’ groups revealed three different layers of the wall of both right and left ventricles; endocardium, myocardium, and epicardium. The endocardium was lined with endothelium and filled with fibrous connective tissue. The endocardium of adult bovine was the thickest. Purkinje fibers appeared of pale cytoplasm with few myofibrils. They were present in the deep layer of the endocardium and in the myocardium. The size of Purkinje fibers and the amount of their myofibrils appeared to be increased with advanced age. Bundles of cardiac muscles were the main constituent of the myocardium. The myocardial bundles were separated by fine connective tissue in immature animals that showed an increased amount in the adult animals. The hypereosinophilic cardiac muscle cells were observed in the ventricles of both mature and adult animals suggesting hypercontraction during rigor mortis. An external layer of the ventricles was the epicardium which consisted of connective tissue and covered with mesothelium.

Conclusion:

Overall, this study revealed histological changes in the wall of the ventricle and Purkinje fibers of Egyptian bovines (B. aegyptiacus) in relation to age. Additionally, the hypereosinophilia of the cardiac muscle cells was recorded in the ventricles of mature and adult bovines.

Temporal Horn Choroid Plexus Papilloma Presenting with Seizures in Adulthood: Clinical Case Report and Review of the Literature

BACKGROUND

Choroid plexus papillomas (CPPs) are benign World Health Organization grade I tumors that comprise 2%-4% of all brain tumors among children and less than 1% of brain tumors in adults. Most adult cases occur in the fourth ventricle, with only 1 previous report describing an adult patient with a temporal horn CPP.

CASE DESCRIPTION

We report a rare case of a temporal horn CPP presenting in an adult with seizures. We performed a minimally invasive subtemporal approach for gross total resection of the lesion.

CONCLUSIONS

CPP presenting in the temporal horn is rare among adults. We discuss the surgical nuances of the subtemporal approach for resection and review the literature regarding adult presentation of CPP and the treatment strategies for adult CPP.

Identification of optimal reference genes for transcriptomic analyses in normal and diseased human heart

Aims

Quantitative real-time RT-PCR (RT-qPCR) has become the method of choice for mRNA quantification, but requires an accurate normalization based on the use of reference genes showing invariant expression across various pathological conditions. Only few data exist on appropriate reference genes for the human heart. The objective of this study was to determine a set of suitable reference genes in human atrial and ventricular tissues, from right and left cavities in control and in cardiac diseases.

Methods and results

We assessed the expression of 16 reference genes (ACTB, B2M, GAPDH, GUSB, HMBS, HPRT1, IPO8, PGK1, POLR2A, PPIA, RPLP0, TBP, TFRC, UBC, YWHAZ, 18S) in tissues from: right and left ventricles from healthy controls and heart failure (HF) patients; right-atrial tissue from patients in sinus rhythm with (SRd) or without (SRnd) atrial dilatation, patients with paroxysmal (pAF) or chronic (cAF) atrial fibrillation or with HF; and left-atrial tissue from patients in SR or cAF. Consensual analysis (by geNorm and Normfinder algorithms, BestKeeper software tool and comparative delta-Ct method) of the variability scores obtained for each reference gene expression shows that the most stably expressed genes are: GAPDH, GUSB, IPO8, POLR2A, and YWHAZ when comparing either right and left ventricle or ventricle from healthy controls and HF patients; GAPDH, IPO8, POLR2A, PPIA, and RPLP0 when comparing either right and left atrium or right atria from all pathological groups. ACTB, TBP, TFRC, and 18S genes were identified as the least stable.

Conclusions

The overall most stable reference genes across different heart cavities and disease conditions were GAPDH, IPO8, POLR2A and PPIA. YWHAZ or GUSB could be added to this set for some specific experiments. This study should provide useful guidelines for reference gene selection in RT-qPCR studies in human heart.

Knockout of adenylyl cyclase isoform 5 or 6 differentially modifies the β1-adrenoceptor-mediated inotropic response

Although only β₂-adrenergic receptors (βAR) dually couple with stimulatory G protein (G_s) and inhibitory G protein (G_i), inactivation of G_i enhances both β₁AR and β₂AR responsiveness. We hypothesize that G_i restrains spontaneous adenylyl cyclase (AC) activity independent of receptor activation. Subcellular localization of the AC5/6 subtypes varies contributing to the compartmentation of βAR signaling. The primary objectives were to determine: (1) if β₁AR-mediated inotropic responses were dependent upon either AC5 or AC6; (2) if intrinsic G_i inhibition is AC subtype selective and (3) the role of phosphodiesterases (PDE) 3/4 to regulate β₁AR responsiveness. β₁AR-mediated increases in contractile force and cAMP accumulation in cardiomyocytes were measured from wild type, AC5 and AC6 knockout (KO) mice, with or without pertussis toxin (PTX) pretreatment to inactivate G_i and/or after selective inhibition of PDEs 3/4. Noradrenaline potency at β₁ARs was increased in AC6 KO. PDE4 inhibition increased noradrenaline potency in wild type and AC5 KO, but not AC6 KO. PTX increased noradrenaline potency only in wild type but increased the maximal β₁AR response in all mouse strains. PDE3 inhibition increased noradrenaline potency only in AC5 KO that was treated prior with PTX. β₁AR-evoked cAMP accumulation was increased more by PDE4 inhibition than PDE3 inhibition in wild type and AC5 KO that was amplified by G_i inhibition. These data indicate that β₁AR-mediated inotropic responses are not dependent upon either AC5 or AC6 alone. Inactivation of G_i enhanced β₁AR-mediated inotropic responses despite not coupling to G_i, consistent with G_i exerting a tonic receptor independent inhibition upon AC5/6. PDE4 seems the primary regulator of β₁AR signaling through AC6 in wild type. AC6 KO results in a reorganization of β₁AR compartmentation characterized by signaling through AC5 regulated by G_i, PDE3 and PDE4 that maintains normal contractile function.

Mesencephalic origin of the inferior lobe in zebrafish

BACKGROUND

Although the overall brain organization is shared in vertebrates, there are significant differences within subregions among different groups, notably between Sarcopterygii (lobe-finned fish) and Actinopterygii (ray-finned fish). Recent comparative studies focusing on the ventricular morphology have revealed a large diversity of the hypothalamus. Here, we study the development of the inferior lobe (IL), a prominent structure forming a bump on the ventral surface of the teleost brain. Based on its position, IL has been thought to be part of the hypothalamus (therefore forebrain).

RESULTS

Taking advantage of genetic lineage-tracing techniques in zebrafish, we reveal that cells originating from her5-expressing progenitors in the midbrain-hindbrain boundary (MHB) participate in the formation of a large part of the IL. 3D visualization demonstrated how IL develops in relation to the ventricular system. We found that IL is constituted by two developmental components: the periventricular zone of hypothalamic origin and the external zone of mesencephalic origin. The mesencephalic external zone grows progressively until adulthood by adding new cells throughout development.

CONCLUSION

Our results disprove a homology between the IL and the mammalian lateral hypothalamus. We suggest that the IL is likely to be involved in multimodal sensory integration rather than feeding motivation. The teleost brain is not a simpler version of the mammalian brain, and our study highlights the evolutionary plasticity of the brain which gives rise to novel structures.

[Prevalence of the proximal aortic root dilatation and it relationship with left ventricular remodelling among South-Kivu Congolese patients: A cross sectional study]

AIM

Studies of the influence of aortic root remodelling on the left ventricle are scarce in sub Saharan Africa even though this region has got high prevalence of arterial hypertension which is positively related to sinuses of Valsalva diameter. The present work aims to determine the frequency of the proximal aortic root enlargement and to evaluate its association with the left ventricle structure and function respectively among Congolese patients.

METHOD

Four hundreds and three (403) patients who realised transthoracic cardiac echography were recruited. The association between the proximal aortic root diameter and the left ventricular echocardiographic parameters was modelised in a multiple linear regression using the Stepwise method.

RESULTS

Among the 403 patients, 69.4% were hypertensive. A multivariate linear regression analysis showed correlations between the proximal aortic root diameter and the left ventricular mass (β=1.12; P=0.01), the left ventricular diastolic diameter (β=0.26, P=0.001) and the E/A ratio (β=-0.02; P<0.0001) respectively. The independent predictor of the proximal aortic root diameter were age (β=0.06, P=0.0006), duration of arterial hypertension (β=0.11, P=0.002) and diastolic blood pressure (β=0.03; P=0.02). The frequency of the proximal aortic root dilatation was 3.5%.

CONCLUSION

These results infancies the importance of including the proximal aortic root dilatation as specific infra clinic risk factor among Congolese.

Outcomes of Left Ventricular Function According to Treatment Response for a Patent Ductus Arteriosus in Preterm Infants

Background

To evaluate the outcomes of left ventricular (LV) function according to treatment response for a hemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants.

Methods

Echocardiograms of 21 preterm infants born at gestational age < 31 weeks obtained at term-equivalent age were retrospectively studied. Among preterm infants with a hsPDA, 9 underwent ligation after failure of pharmacological closure (ligation group) and 6 experienced successful pharmacological closure (medication group). Six preterm infants without hsPDA (no-hsPDA group) were studied as controls. LV peak longitudinal systolic strain (ε) of each infant was retrospectively obtained from echocardiograms using velocity vector imaging, along with neonatal outcomes.

Results

Pharmacological closures were attempted at postnatal day 2-3. In the ligation group, the median postnatal age at ligation was 20 days. In the ligation group, LV peak longitudinal systolic ε was significantly decreased at term-equivalent age compared to the other groups. Between the medication and no-hsPDA groups, LV peak longitudinal systolic ε did not differ significantly. Among the neonatal outcomes, infants who experienced necrotizing enterocolitis (NEC) showed significantly decreased LV peak longitudinal systolic ε compared to the infants who did not experience NEC .

Conclusion

We speculate that in preterm infants with an hsPDA, in cases of medical treatment failure, early PDA ligation at less than 20 days of postnatal age would be beneficial for preserving LV systolic function.

Voltage dependence of the Ca2+ transient in endocardial and epicardial myocytes from the left ventricle of Goto-Kakizaki type 2 diabetic rats

Diabetes mellitus is a major global health disorder and, currently, over 450 million people have diabetes with 90% suffering from type 2 diabetes. Left untreated, diabetes may lead to cardiovascular diseases which are a leading cause of death in diabetic patients. Calcium is the trigger and regulator of cardiac muscle contraction and derangement in cellular Ca²⁺ homeostasis, which can result in heart failure and sudden cardiac death. It is of paramount importance to investigate the regional involvement of Ca²⁺ in diabetes-induced cardiomyopathy. Therefore, the aim of this study was to investigate the voltage dependence of the Ca²⁺ transients in endocardial (ENDO) and epicardial (EPI) myocytes from the left ventricle of the Goto-Kakizaki (GK) rats, an experimental model of type 2 diabetes mellitus. Simultaneous measurement of L-type Ca²⁺ currents and Ca²⁺ transients was performed by whole-cell patch clamp techniques. GK rats displayed significantly increased heart weight, heart weight/body weight ratio, and non-fasting and fasting blood glucose compared to controls (CON). Although the voltage dependence of L-type Ca²⁺ current was unaltered, the voltage dependence of the Ca²⁺ transients was reduced to similar extents in EPI-GK and ENDO-GK compared to EPI-CON and ENDO-CON myocytes. TPK L-type Ca²⁺ current and Ca²⁺ transient were unaltered. THALF decay of L-type Ca²⁺ current was unaltered; however, THALF decay of the Ca²⁺ transient was shortened in ENDO and EPI myocytes from GK compared to CON rat hearts. In conclusion, the amplitude of L-type Ca²⁺ current was unaltered; however, the voltage dependence of the Ca²⁺ transient was reduced to similar extents in EPI and ENDO myocytes from GK rats compared to their respective controls, suggesting the possibility of dysfunctional sarcoplasmic reticulum Ca²⁺ transport in the GK diabetic rat hearts.

Proteomic analysis of cardiac ventricles: baso-apical differences

The heart is characterized by a remarkable degree of heterogeneity. Since different cardiac pathologies affect different cardiac regions, it is important to understand molecular mechanisms by which these parts respond to pathological stimuli. In addition to already described left ventricular (LV)/right ventricular (RV) and transmural differences, possible baso-apical heterogeneity has to be taken into consideration. The aim of our study has been, therefore, to compare proteomes in the apical and basal parts of the rat RV and LV. Two-dimensional electrophoresis was used for the proteomic analysis. The major result of this study has revealed for the first time significant baso-apical differences in concentration of several proteins, both in the LV and RV. As far as the LV is concerned, five proteins had higher concentration in the apical compared to basal part of the ventricle. Three of them are mitochondrial and belong to the "metabolism and energy pathways" (myofibrillar creatine kinase M-type, L-lactate dehydrogenase, dihydrolipoamide dehydrogenase). Myosin light chain 3 is a contractile protein and HSP60 belongs to heat shock proteins. In the RV, higher concentration in the apical part was observed in two mitochondrial proteins (creatine kinase S-type and proton pumping NADH:ubiquinone oxidoreductase). The described changes were more pronounced in the LV, which is subjected to higher workload. However, in both chambers was the concentration of proteins markedly higher in the apical than that in basal part, which corresponds to the higher energetic demand and contractile activity of these segments of both ventricles.

Survival of Ventricular and Periventricular High-Grade Gliomas: A Surveillance, Epidemiology, and End Results Program-Based Study

BACKGROUND

Aggressiveness of surgical resection for periventricular/ventricular high-grade gliomas (HGGs) is determined by operative risks and assumed effectiveness of radiation therapy (RT) on residual tumor. We aimed to clarify the impact of surgery and postoperative RT on patient survival in a population-based study.

METHODS

This population-based study used the Surveillance, Epidemiology, and End Results (SEER) database. Patients with ventricular malignant tumors were screened for HGGs. In accordance with the World Health Organization (WHO) 2016 classification, we included cases with "diffuse astrocytic and oligodendroglial tumors," "other astrocytic tumors," "ependymal tumors," and "other gliomas". Tumor grading followed definitions established by the WHO with supplementation from SEER classifications. Only grades III and IV were included. Individual factors were assessed by hazard ratio (HR) from multivariable survival analysis using accelerated failure time (AFT) regression.

RESULTS

We included 353 patients after application of inclusion and exclusion criteria. The mean patient age was 38.77 ± 24.95 years, and the cohort was 61.5% male. Overall median survival was 12 months, with notable improvement over the last 3 decades. In a multivariate AFT model, older age (per 10-year increase, HR, 1.19; P < 0.001) was the sole nontreatment variable found to predict survival, whereas postoperative RT had a significant survival benefit (HR, 0.50; P < 0.001). No tumor characteristic (e.g., size, extent of invasion) predicted prognosis. Interestingly, neither partial resection nor TR/GTR was associated with improved outcome.

CONCLUSIONS

The prognosis of ventricular HGGs is poor, with worse prognosis in older patients. We found no evidence to support aggressive surgical resection. Postoperative chemoradiation should be administered; however, the benefit of modification of the protocol for chemoradiation specifically for ventricular HGGs remains unknown and warrants further investigation.

Quantification of Cell-Surface Glucose Transporters in the Heart Using a Biotinylated Photolabeling Assay

The biotinylated photolabeling assay enables quantification of cell-surface glucose transporters (GLUTs). This technique has been successfully applied to quantify the cell-surface GLUT protein content in striated muscles and adipose tissue, as a means to evaluate GLUT trafficking. Here, we describe the detailed method of quantifying the cell-surface content of several GLUT isoforms (1, 4, 8, and 12) in isolated cardiac myocytes, as well as in the intact perfused atria and ventricle.

Transcatheter Mitral Valve Implantation in Open Heart Surgery: An Off-Label Technique

Extensive mitral annulus calcifications are considered a contraindication for valve surgery. We describe the case of a 76-year-old female with severe mitral and aortic stenosis associated with extensive calcifications of the heart. The patient underwent an open mitroaortic valve replacement using transcatheter aortic valve implantation with an Edwards SAPIEN XT valve (Edwards Lifesciences Corp., Irvine, CA, USA) in the mitral position. The aortic valve was replaced using a stentless valve prosthesis (LivaNova SOLO; LivaNova PLC, London, UK). Postoperative echocardiography showed that the prosthetic valve was in the correct position and there were no paravalvular leaks. A bailout open transcatheter valve implantation can be considered a safe and effective option in selected cases with an extensively calcified mitral valve.