Contractile Patterns Research Articles

777: Hypothyroidism treatment modify uterine contractility pattern in vitro

777: Hypothyroidism treatment modify uterine contractility pattern in vitro

Patterns in Space: Coordinating Adhesion and Actomyosin Contractility at E-cadherin Junctions

Cadherin adhesion receptors are fundamental determinants of tissue organization in health and disease. Increasingly, we have come to appreciate that classical cadherins exert their biological actions through active cooperation with the contractile actin cytoskeleton. Rather than being passive resistors of detachment forces, cadherins can regulate the assembly and mechanics of the contractile apparatus itself. Moreover, coordinate spatial patterning of adhesion and contractility is emerging as a determinant of morphogenesis. Here we review recent developments in cadherins and actin cytoskeleton cooperativity, by focusing on E-cadherin adhesive patterning in the epithelia. Next, we discuss the underlying principles of cellular rearrangement during Drosophila germband extension and epithelial cell extrusion, as models of how planar and apical-lateral patterns of contractility organizes tissue architecture.

Intracellular Acidification Alters Myogenic Responsiveness and Vasomotion of Mouse Middle Cerebral Arteries

Intracellular pH (pHi) in the vascular wall modulates agonist-induced vasocontractile and vasorelaxant responses in mesenteric arteries, whereas effects on myogenic tone have been unsettled. We studied the role of Na(+),HCO3(-) cotransporter NBCn1 in mouse isolated middle cerebral arteries and the influence of pHi disturbances on myogenic tone. Na(+),HCO3(-) cotransport was abolished in arteries from NBCn1 knockout mice and steady-state pHi ∼0.3 units reduced compared with wild-type mice. Myogenic tone development was low under control conditions but increased on treatment with the NO-synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME). This effect of L-NAME was smaller in arteries from NBCn1 knockout than wild-type mice. Myogenic tone with L-NAME present was significantly lower in arteries from NBCn1 knockout than wild-type mice and was abolished by rho-kinase inhibitor Y-27632. The arteries displayed vasomotion, and this rhythmic contractile pattern was also attenuated in arteries from NBCn1 knockout mice. No differences in membrane potential or intracellular [Ca(2+)] were seen between arteries from NBCn1 knockout and wild-type mice. We propose that NO production and rho-kinase-dependent Ca(2+) sensitivity are reduced at low pHi in pressurized mouse middle cerebral arteries. This likely impedes the ability to adjust to changes in perfusion pressure and regulate cerebral blood flow.

Comparative Evaluation of 25µg and 50µg of travaginal Misoprostol for Induction of Labor


 Introduction: To compare the efficacy and safety of 25g vs. 50g of intravaginal (Posterior fornix) misoprostol for induction of labor in 100 patient from Jan 2012 to Dec 2012 at Lumbini Medical College.
 
 Methods: One hundred pregnant lady requiring induction were randomly assigned to receive either 25 g (group A=50) or 50 g (group B=50) of intra vaginal misoprostol every 4 hrs till adequate contractions were achieved or maximum dose of 150 g was used.
 
 Results: The onset of contraction was earlier in group B in 34 cases as compared to group A, where only 25 cases had earlier contraction ( P> 0.05). 38 cases (76%) in Group B and 35 cases (70%) in Group A delivered vaginally. Induction to delivery interval was shorter(<12hrs) in group B in 15 cases and in 10 cases in group A. Mean dose of Misoprostol (94micrograms) for successful induction in group B was high compared to Group A (75.5 microgram). Requirement for oxytocin infusion was higher in group A, 26% vs. 15%. Abnormal contractility pattern was seen in B group 24% cases compared to 14% cases in Group A. APGAR score < 7 at 1 min was seen in 26% neonates in Group B and in only 10% neonates in Group A. Ruptured uterus did not occur in any group.
 
 Conclusion: 50 g dose of misoprostol is more efficacious than 25 g dose as seen in our study. However it appears to be less safe both for mother and baby due to the high incidence of tachysystole, hyperstimulation and intrauterine passage of meconium.

Marked changes in right ventricular contractile pattern after cardiothoracic surgery: Implications for post-surgical assessment of right ventricular function

Longitudinal shortening accounts for the majority of right ventricular (RV) contraction in normal hearts. This finding accounts for the correlation between longitudinal measures of RV contraction such as tricuspid annular plane systolic excursion (TAPSE) and global RV function. We hypothesized that, after cardiac surgery, there are major differences in the RV contractile pattern relative to normal hearts. We retrospectively studied 2 cardiac surgical cohorts who underwent cardiopulmonary bypass (CPB) with pericardial incision (OHT, n = 54; CABG, n = 23) and compared them with a lung transplant cohort (n = 25). We compared TAPSE, RV fractional area change (RVFAC) and relative change in RV transverse and longitudinal area in the surgical cohorts with data from normal subjects (n = 84). RVFAC was lower in the surgical groups compared with the normal group, yet still in the normal range (37% to 42% vs 47%; p < 0.01). TAPSE was markedly lower in OHT (15 ± 3 mm) and CABG (16 ± 4 mm) than in normal (26 ± 4 mm) subjects (p < 0.01), as was the relative contribution of longitudinal area change (OHT group 51 ± 11%, CABG group 54 ± 13%, normal group 78 ± 14%; p < 0.01). The ratio of TAPSE to RVFAC was markedly lower in CABG (40 ± 14 mm/%FAC) and OHT (37 ± 10 mm/%FAC) patients than in normal (56 ± 14 mm/%FAC) subjects (p < 0.001). However, OLT patients had a higher TAPSE (18 ± 3 mm) than OHT (15 ± 3 mm) and CABG (16 ± 4 mm) patients (p < 0.01) and a higher relative contribution of longitudinal area change: OLT 67 ± 10%; OHT 51 ± 11%; and CABG 54 ± 13% (p < 0.01). After cardiac surgery, the RV contractile pattern changes, with a relative loss of longitudinal shortening and gain in transverse shortening despite normal global RV function. These findings have major implications for quantitative assessment of RV function after cardiac surgery, suggesting that global measures of RV function assessment may be preferred in this setting and that lower normative ranges should be used when measurement of RV function is performed with longitudinal methods.

Contractile behavior of the uterine lymphatic vessels

While various lymphatic vessels networks are shown to adapt their contractility to changes in wall stretch and wall shear stress, until now, little is known on physiological characteristics of uterine lymphatic vessels (LV) in both the non‐pregnant and pregnant uterus. In this study we for the first time performed detailed evaluation of the contractile characteristics of the collecting uterine LV from ~250 g female non‐pregnant Sprague‐Dawley rats. Changes in lymphatic diameter were recorded with their subsequent analysis and calculation of the lymphatic pump indices of isolated, cannulated and pressurized rat uterine LV at different ranges of pressure and imposed flow in control conditions and after L‐NAME application. We found, that pressure stimulates contractility of rat uterine LV with contraction amplitude and pumping maximum at 1 cm H2O, while contraction frequency is almost stretch‐insensitive. NO had only a minor involvement in this regulation. These vessels also demonstrated a minor imposed‐flow/ wall shear stress‐dependent inhibition of tone, contraction amplitude and pump flow, but not contraction frequency. L‐NAME did not eliminate this flow/shear dependency, but induced flow‐independent shifts of all parameters of contractility of these vessels. In summary, our preliminary data show that uterine LV possesses unique contractile patterns different from other regional LV. NIH RO1 HL‐070308

Presentation, Diagnosis, and Management of Achalasia

Presentation, Diagnosis, and Management of Achalasia

Partial Recovery of Peristalsis After Myotomy for Achalasia

Although successful treatment of achalasia depends on alleviating the obstruction at the esophagogastric junction, the postintervention contractile and pressurization pattern may also play a role in outcome. To determine whether myotomy that alleviates the esophagogastric junction outflow obstruction in achalasia might improve peristalsis. Retrospective study from August 1, 2004, through January 30, 2012. Two tertiary care hospitals in Chicago and Lyon. We included 30 patients (18 male; mean age [range], 43 [17-78] years), of whom 8 had type 1 (26.6%), 17 had type 2 (56.7%), and 5 (16.7%) had type 3 achalasia according to the Chicago classification. Esophageal high-resolution manometry before and after laparoscopic or endoscopic myotomy. The integrity of peristalsis, characterized as intact, weak contractions; frequent failed peristalsis; or premature contractions. Although peristaltic fragments were evident only in patients with type 3 achalasia before treatment, intact, weak, or frequent failed peristalsis was encountered in 5 patients with type 1 (63%), 8 with type 2 (47%), and 4 with type 3 (80%) achalasia after myotomy. One patient with type 3 achalasia had distal esophageal spasm after treatment. In patients with a postmyotomy integrated relaxation pressure of less than 15 mm Hg, only 10 (40%) had persistent absent peristalsis. Panesophageal pressurization disappeared after myotomy in 16 of 19 patients. In the 5 patients with postmyotomy integrated relaxation pressure of more than 15 mm Hg, 4 had weak peristalsis and 1 had absent peristalsis. Reduction or normalization of the esophagogastric junction relaxation pressure achieved by myotomy in achalasia is associated with partial recovery of peristalsis in some patients, suggesting that the disease process progresses from the esophagogastric junction to the esophageal body. Whether the return of peristalsis is predictive of an improved therapeutic outcome requires further study.

Classification of normal and abnormal colonic motility based on cross‐correlations of pancolonic manometry data

Manual analysis of data acquired from manometric studies of colonic motility is laborious, subject to laboratory bias and not specific enough to differentiate all patients from control subjects. Utilizing a cross-correlation technique, we have developed an automated analysis technique that can reliably differentiate the motor patterns of patients with slow transit constipation (STC) from those recorded in healthy controls. Pancolonic manometric data were recorded from 17 patients with STC and 14 healthy controls. The automated analysis involved calculation of an indicator value derived from cross-correlations calculated between adjacent recording sites in a manometric trace. The automated technique was conducted on blinded real data sets (observed) and then to determine the likelihood of positive indicator values occurring by chance, the channel number within each individual data set were randomized (expected) and reanalyzed. In controls, the observed indicator value (3.2 ± 1.4) was significantly greater than that predicted by chance (0.8 ± 1.5; P < 0.0001). In patients, the observed indicator value (-2.7 ± 1.8) did not differ from that predicted by chance (-3.5 ± 1.6; P = 0.1). The indicator value for controls differed significantly from that of patients (P < 0.0001), with all individual patients falling outside of the range of indicator values for controls. Automated analysis of colonic manometry data using cross-correlation separated all patients from controls. This automated technique indicates that the contractile motor patterns in STC patients differ from those recorded in healthy controls. The analytical technique may represent a means for defining subtypes of constipation.

Non-genomic effects of progesterone on Rho kinase II in rat gastric smooth muscle cells

Various studies have shown that pregnancy is associated with gastrointestinal complaints that might result from disturbance of the normal contractile pattern of smooth muscle. Progesterone is an important steroid hormone, which plays a crucial role in female pregnancy. Progesterone affects muscle cells by genomic mechanisms, through nuclear receptors, and non-genomic mechanisms, through unidentified pathways. Non-genomic actions were defined as those occurring within 10 min of progesterone exposure. The aim of the present study was to investigate the non-genomic effect of progesterone on Rho kinase II activity in gastric smooth muscle. Single smooth muscle cells of the stomach obtained from Sprague Dawley rats were used. Dispersed gastric smooth muscle cells were treated with progesterone or acetylcholine (ACh) separately. Cells designated for progesterone treatment were incubated with 1 μM progesterone for 10 min. Rho kinase II expression and both basal and ACh-induced Rho kinase II activity were measured via specifically designed enzyme-linked immunosorbent assay (ELISA) and activity assay kits respectively in both control and progesterone-treated groups. Progesterone inhibited the ACh-induced, but not the basal, Rho kinase II activity in dispersed gastric smooth muscle cells without affecting its expression level. This study suggested that progesterone can rapidly affect the contractile activity of isolated gastric smooth muscle cells in rats via inhibition of the Rho kinase II pathway.

Rho‐kinase mediates diphosphorylation of myosin regulatory light chain in cultured uterine, but not vascular smooth muscle cells

Phosphorylation of myosin regulatory light chain (RLC) triggers contraction in smooth muscle myocytes. Dephosphorylation of phosphorylated RLC (pRLC) is mediated by myosin RLC phosphatase (MLCP), which is negatively regulated by rho-associated kinase (ROK). We have compared basal and stimulated concentrations of pRLC in myocytes from human coronary artery (hVM), which has a tonic contractile pattern to myocytes from human uterus (hUM), which has a phasic contractile pattern. Our studies reveal fundamental differences between hVM and hUM regarding the mechanisms regulating phosphorylation RLC. Whereas hVM responded to stimulation by phosphorylation of RLC at S19, hUM responded by forming diphosphorylated RLC (at T18 and S19; ppRLC), which, compared to pRLC, causes two to threefold greater activation of myosin ATPase that provides energy to power the contraction. Importantly, the conversion of pRLC to ppRLC is mediated by ROK. In hUM, MLCP has high activity for ppRLC and this is inhibited by ROK through phosphorylation of the substrate targeting subunit (MYPT1) at T853. Inhibitors of ROK significantly reduce contractility in both hVM and hUM. We demonstrated that inhibition of ppRLC in phasic myocytes (hUM) is 100-fold more sensitive to ROK inhibitors than is pRLC in tonic myocytes (hVM). We speculate that these differences in phosphorylation of RLC might reflect evolution of different contractile patterns to perform distinct physiological functions. Furthermore, our data suggest that low concentrations of ROK inhibitors might inhibit uterine contractions with minimal effects on vascular tone, thus posing a novel strategy for prevention or treatment of conditions such as preterm birth.

Pheochromocytoma-induced reverse tako-tsubo with rapid recovery of left ventricular function

Pheochromocytoma is a rare, catecholamine-secreting tumor of neuroendocrine cells. It has been documented to present atypically as myocardial ischemia, arrhythmias, or congestive heart failure. We present the case of a patient who had transient cardiomyopathy with hypokinesia of the basal portions of the left ventricle and hyperkinesia of the apex triggered by a pheochromocytoma crisis similar to that of tako-tsubo cardiomyopathy, but with an inverse left ventricular contractile pattern ('inverted tako-tsubo').

Marked Changes in Right Ventricular Contractile Pattern After Cardiac Surgery May Be Secondary to Pericardial Incision: Implications for the Post-Surgical Assessment of Right Ventricular Function

Marked Changes in Right Ventricular Contractile Pattern After Cardiac Surgery May Be Secondary to Pericardial Incision: Implications for the Post-Surgical Assessment of Right Ventricular Function

The role of echocardiography in the assessment of right ventricular systolic function in patients with transposition of the great arteries and atrial redirection

Although dysfunction of the systemic right ventricle (RV) in patients with complete transposition of the great arteries (TGA) after atrial redirection by Mustard or Senning procedures is well recognized, there are few data on systemic RV geometry and function. Echocardiography is a widely available imaging technique that is particularly suitable for clinical follow-up because of its non-invasive nature, low cost and lack of ionizing radiation. To examine the feasibility and variability of transthoracic echocardiography variables in the assessment of the systemic RV. Multivariable transthoracic echocardiographic analysis, including assessment of global function variables (RV ejection fraction [RVEF; Simpson's method], RV fractional shortening [RVFS] and dP/dt), longitudinal function variables (tricuspid annular plane systolic excursion [TAPSE], peak systolic velocity at the junction of the RV free wall and the tricuspid annulus, assessed with pulsed tissue Doppler imaging [S' TDI]), tricuspid regurgitation and asynchrony, was performed in 35 consecutive patients with TGA after atrial redirection. Functional variables were compared with magnetic resonance imaging (MRI). Inter- and intraobserver echocardiographic analysis variability was assessed in ten randomly selected cases. Global and longitudinal function variables were not correlated with RVEF calculated by MRI, except for S' TDI, which was weakly correlated (P = 0.02, r = 0.37). Asynchrony assessment was feasible in all patients. Inter- and intraobserver echocardiographic analysis variability was high for RVEF, RVFS and dP/dt (> 10%), and low for TAPSE and S' TDI (5%). Owing to geometric changes, presumed contractility pattern shift and retrosternal position, conventional echocardiographic variables are not relevant for RV function assessment. Assessment of asynchrony and tricuspid regurgitation is easily feasible in routine practice and highly reproducible. Echocardiography does not permit complete assessment of the systemic RV after atrial redirection but is fully complementary with MRI and should not be abandoned. Future improvements in transducers and dedicated software should permit major improvements in the near future.

Contractile and Electrophysiologic Characterization of Optimized Self-Organizing Engineered Heart Tissue

Engineered heart tissue (EHT) is being developed for clinical implantation in heart failure or congenital heart disease and therefore requires a comprehensive functional characterization and scale-up of EHT. Here we explored the effects of scale-up of self-organizing EHT and present detailed electrophysiologic and contractile functional characterization. Fibers from EHT were generated from self-organizing neonatal rat cardiac cells (0.5×10(6) to 3×10(6)/fiber) on fibrin. We characterized contractile patterns and measured contractile function using a force transducer, and assessed force-length relationship, maximal force generation, and rate of force generation. Action potential and conduction velocity of EHT were measured with optical mapping, and transcript levels of myosin heavy chain beta were measured by reverse transcriptase-polymerase chain reaction. Increasing the cell number per construct resulted in an increase in fiber volume. The force-length relationship was negatively impacted by increasing cell number. Maximal force generation and rate of force generation were also abrogated with increasing cell number. This decrease was not likely attributable to a selective expansion of noncontractile cells as myosin heavy chain beta levels were stable. Irregular contractile behavior was more prevalent in constructs with more cells. Engineered heart tissue (1×10(6)/construct) had an action potential duration of 140.2 milliseconds and a conduction velocity of 23.2 cm/s. Engineered heart tissue displays physiologically relevant features shared with native myocardium. Engineered heart tissue scale-up by increasing cell number abrogates contractile function, possibly as a result of suboptimal cardiomyocyte performance in the absence of vasculature. Finally, conduction velocity approaches that of native myocardium without any electrical or mechanical conditioning, suggesting that the self-organizing method may be superior to other rigid scaffold-based EHT.

Refining the criterion for an abnormal Integrated Relaxation Pressure in esophageal pressure topography based on the pattern of esophageal contractility using a classification and regression tree model

The Integrated Relaxation Pressure (IRP) is the esophageal pressure topography (EPT) metric used for assessing the adequacy of esophagogastric junction (EGJ) relaxation in the Chicago Classification of motility disorders. However, because the IRP value is also influenced by distal esophageal contractility, we hypothesized that its normal limits should vary with different patterns of contractility. Five hundred and twenty two selected EPT studies were used to compare the accuracy of alternative analysis paradigms to that of a motility expert (the 'gold standard'). Chicago Classification metrics were scored manually and used as inputs for MATLAB™ programs that utilized either strict algorithm-based interpretation (fixed abnormal IRP threshold of 15 mmHg) or a classification and regression tree (CART) model that selected variable IRP thresholds depending on the associated esophageal contractility. The sensitivity of the CART model for achalasia (93%) was better than that of the algorithm-based approach (85%) on account of using variable IRP thresholds that ranged from a low value of >10 mmHg to distinguish type I achalasia from absent peristalsis to a high value of >17 mmHg to distinguish type III achalasia from distal esophageal spasm. Additionally, type II achalasia was diagnosed solely by panesophageal pressurization without the IRP entering the algorithm. Automated interpretation of EPT studies more closely mimics that of a motility expert when IRP thresholds for impaired EGJ relaxation are adjusted depending on the pattern of associated esophageal contractility. The range of IRP cutoffs suggested by the CART model ranged from 10 to 17 mmHg.

ST-elevation during surgery in a young male: who would bet on inverted takotsubo syndrome?

We report the case of a 21-year old man active smoker, admitted to hospital for acute scrotal pain suspicious of testicular torsion. He underwent an emergency surgical exploration complicated by extreme sinus bradycardia (~20 bpm), successfully treated with atropine; neither epinephrine nor any other adrenergic agent was administered. After restoring the normal heart rate the ECG revealed an ST-segment elevation in the anterolateral leads. Transthoracic echocardiography showed reduced left ventricular ejection fraction (LVEF; 40%) due to diffuse severe hypokinesis except for the apex that appeared hyperkinetic. Emergency coronary angiography revealed normal coronary arteries (Fig. 1, Video 1). Left ventriculography showed akinesia of the mid and basal segments with concomitant hyperkinesis of the apex, resembling to the contractile pattern of apical sparing takotsubo cardiomyopathy (TTC) (Fig. 1, Video 2–3). Troponin peak was 31.60 ng/ml (upper limit of normal 1.20 ng/ml). We diagnosed inverted type of TTC occurred in a young male triggered by a physical stress. Patient was treated with Beta-blockers and ACE Inhibitors. At discharge five days later, the patient was asymptomatic and the ECG was unremarkable. Echocardiography disclosed improved LVEF (55%) but residual hypokinesis of the mid segments. At 2-weeks

Sa1355 Improving the Integrated Relaxation Pressure Cutoff Value for the Diagnosis of Achalasia Using a Classification and Regression Tree Model

Background: The Integrated Relaxation Pressure (IRP) is a fundamental measurement utilized in Esophageal Pressure Topography (EPT) to assess the pressure dynamics through the esophagogastric junction (EGJ) during swallowing. Data from control subjects suggest that a cutoff of 15 mmHg is a reliable upper limit of normal in the context of propagating peristalsis. Given the interdependence of the IRP and intrabolus pressure during bolus transit, we hypothesized that this value may need to be adjusted when peristalsis is weak, absent or spastic. The aim of this study was to define optimal IRP cutoff values for diagnosing achalasia subtypes using a classification and regression (CART) model. Methods: EPT studies from 522 consecutive patients were studied (10 supine water swallows). Mean IRP values and EPT swallow patterns from each study based on Chicago Classification criteria were used as inputs to train and test a classification and regression tree (CART) model with a MATLABTM program. CART model diagnoses were compared to those of an expert blinded reviewer (JEP). Results: The diagnoses of the 522 patients were: 110 normal, 110 weak peristalsis, 72 frequent failed peristalsis, 28 absent peristalsis, 11 distal esophageal spasm (DES), 11 rapid contractions, 32 hypertensive peristalsis, 21 jackhammer/hypercontractile esophagus, 71 achalasia (type I, II, or III) and 56 EGJ outflow obstruction. The CART model achieved 94% agreement with the expert. The optimal IRP cutoff values varied based on contractile pattern. In the context of absent peristalsis, a cutoff value of ≥ 10 mmHg best distinguished type I achalasia from absent peristalsis. Additionally, a cutoff value of ≥17 mmHg best distinguished type III achalasia from DES while an IRP value of ≥15 was predictive of achalasia when contractile activity was associated with panesophageal pressurization (type II achalasia). The optimal IRP threshold for defining EGJ outflow obstruction was ≥ 15 mmHg. Overall, the accuracy using the CART model for achalasia was 96 % compared to 87% using the standard criterion of a single cutoff value of ≥ 15 mmHg. Conclusion: Applying a CART model, the optimal IRP cutoff value for diagnosing achalasia is modified depending on the associated distal esophageal contractility. The optimal IRP threshold for distinguishing type I achalasia from absent peristalsis is reduced to ≥10 mmHg due to the low intrabolus pressure associated with absent peristalsis. The optimal IRP threshold for distinguishing type III achalasia from DES is increased secondary to the effect of reduced latency on shortening the deglutitive relaxation window to less than 4.5 seconds. Patients with DES may have IRP values that are slightly higher than the standard 15 mmHg threshold, however, the values are usually less than 17 mmHg and associated with a normal nadir EGJ relaxation pressure.

A potential role for differential contractility in early brain development and evolution

Differences in brain structure between species have long fascinated evolutionary biologists. Understanding how these differences arise requires knowing how they are generated in the embryo. Growing evidence in the field of evolutionary developmental biology (evo-devo) suggests that morphological differences between species result largely from changes in the spatiotemporal regulation of gene expression during development. Corresponding changes in functional cellular behaviors (morphogenetic mechanisms) are only beginning to be explored, however. Here we show that spatiotemporal patterns of tissue contractility are sufficient to explain differences in morphology of the early embryonic brain between disparate species. We found that enhancing cytoskeletal contraction in the embryonic chick brain with calyculin A alters the distribution of contractile proteins on the apical side of the neuroepithelium and changes relatively round cross-sections of the tubular brain into shapes resembling triangles, diamonds, and narrow slits. These perturbed shapes, as well as overall brain morphology, are remarkably similar to those of corresponding sections normally found in species such as zebrafish and Xenopus laevis (frog). Tissue staining revealed relatively strong concentration of F-actin at vertices of hyper-contracted cross-sections, and a finite element model shows that local contraction in these regions can convert circular sections into the observed shapes. Another model suggests that these variations in contractility depend on the initial geometry of the brain tube, as localized contraction may be needed to open the initially closed lumen in normal zebrafish and Xenopus brains, whereas this contractile machinery is not necessary in chick brains, which are already open when first created. We conclude that interspecies differences in cytoskeletal contraction may play a larger role in generating differences in morphology, and at much earlier developmental stages, in the brain than previously appreciated. This study is a step toward uncovering the underlying morphomechanical mechanisms that regulate how neural phenotypic differences arise between species.

Takotsubo cardiomyopathy associated with hypoglycemia: inverted takotsubo contractile pattern

Classic takotsubo cardiomyopathy (TCM) is characterized by transient dysfunction of the apical portion of the left ventricle with hyperkinesis of the other parts of the heart wall. Recently, wall motion abnormalities in parts other than in the apical portion of the heart have been reported. Inverted TCM is one form of these anomalies. In this form, the basal segments rather than the apical part of the heart are akinetic/dyskinetic, and the apex is hyperdynamic. Emotional or physical stress is known to trigger TCM, leading some authors to call TCM stress-induced cardiomyopathy (SC). Hypoglycemia is regarded as one of the physical stresses that cause TCM/SC. We present a case of inverted TCM/SC with hypoglycemia. In this case, a 60-year-old woman was brought to our hospital with loss of consciousness caused by hypoglycemia. Initially, the echocardiography revealed an inverted takotsubo contractile pattern. The patient was stabilized with continuous intravenous fluids and a glucose injection, whereas the echocardiography on day 4 showed an almost normal contractile pattern. Among the case reports regarding hypoglycemia as a preceding stressor of TCM/SC, a case of inverted TCM/SC with hypoglycemia is rare. Hypoglycemia is a relatively common case in emergency department; however wall motion abnormalities are not usually expected in hypoglycemic patients. Thus, undiagnosed self-limited TCM/SC cases are possible among hypoglycemic patients. TCM/SC is reported to be a cause of torsade de pointes, which can be fatal. This might warrant an echocardiogram for hypoglycemic patients so as not to overlook TCM/SC in the emergency department.