Correlations between clinical motor scores and CMAP in patients with type 2 spinal muscular amyotrophy treated with nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of the anterior horn cells of the spinal cord. Nusinersen for the treatment of SMA has been covered by public healthcare in France since May 2017.

OBJECTIVE

Our aim was to investigate whether there is a correlation between clinical and compound motor action potential (CMAP) measurements in SMA patients treated with nusinersen after 3  years' follow-up.

METHOD

Motor skills were evaluated regularly between M0 and M36 using the Motor Function Measure (MFM) score. CMAP measurements were collected regularly between M0 and M22.

RESULTS

Data for 10 patients with SMA type 2 were collected and divided into two age groups (< 5 years and > 5 years). Motor function improved, but not significantly, regarding distal motor skills (D3) in both groups, and in axial and proximal motor function (D2) in the younger group. CMAP measurements improved in all patients. CMAP increased significantly for the median nerve, and this improvement correlated significantly with global MFM and with axial and proximal tone (D2).

CONCLUSION

Our study shows gain in distal motor function with nusinersen, especially in younger patients with SMA type 2. These results encourage the screening of SMA patients and treatment as early as possible. CMAP measurements of the median nerve show clear improvement in patients treated with nusinersen and could be performed as routine follow-up.

Is cardiac magnetic resonance of additional help in premature ventricular contraction work-up?

Background

Premature ventricular contractions (PVCs) are common in routine medical practice. PVCs are commonly asymptomatic but can also result in palpitations, dyspnea, presyncope or PVC-induced cardiomyopathy that may lead to sudden death. Cardiovascular magnetic resonance (CMR) provides morphological, functional, and tissue characterization in a single setting. CMR imaging proved to reliably identify fibrotic lesions and, hence, has developed into a valuable tool for etiological orientation in patients with PVCs.

Objectives

The aims of this study were: 1) to evaluate which ventricular arrythmia (VA) characteristics predicted CMR abnormalities and 2) the diagnostic yield and the impact in the management of CMR-based imaging versus non-CMR-based imaging in patients referred for PVCs.

Methods

This monocentric retrospective study was conducted in patients with PVCs referred for CMR imaging. Their baseline interview and characteristics, physical examination, surface electrocardiogram (ECG) analysis, ambulatory monitoring, echocardiography and treadmill exercise test data were collected when they were available. The CMR (1,5 T and 3.0 T) protocol included cine imaging and late gadolinium enhancement (LGE) using standard cardiac geometries.

Results

We analyzed 168 patients (65% males, mean age 54.2±16.8 years) referred to our center for PVCs over a two-year period. CMR reported abnormal findings in 73 patients (43.5%) with the diagnosis of structural heart disease (SHD) in 46 patients (27.4%). Left-ventricular late gadolinium-enhancement was documented in 43 patients with abnormal CMR. Using a multivariate analysis, age (p=0.026), sustained ventricular tachycardia (p=0.002) and presence of cardiomyopathy on echocardiography (p&lt;0.001) significantly predicted the presence of abnormal findings on CMR. Compared to non-CMR-based imaging, CMR had a diagnostic yield, by modifying the presumed diagnosis or by finding abnormalities requiring follow-up in 73 patients (43.5%).

Conclusions

Age, sustained ventricular tachycardia and presence of cardiomyopathy on echocardiography were the strongest predictors of positive CMR imaging results. Although echocardiography is generally used in first intention for the diagnosis of cardiomyopathy in patients with PVCs, this study showed that CMR-based imaging has a robust diagnostic yield in this indication.

Funding Acknowledgement

Type of funding sources: None.

Flagella-like beating of actin bundles driven by self-organized myosin waves

Wave-like beating of eukaryotic cilia and flagella-threadlike protrusions found in many cells and microorganisms-is a classic example of spontaneous mechanical oscillations in biology. This type of self-organized active matter raises the question of the coordination mechanism between molecular motor activity and cytoskeletal filament bending. Here we show that in the presence of myosin motors, polymerizing actin filaments self-assemble into polar bundles that exhibit wave-like beating. Importantly, filament beating is associated with myosin density waves initiated at twice the frequency of the actin-bending waves. A theoretical description based on curvature control of motor binding to the filaments and of motor activity explains our observations in a regime of high internal friction. Overall, our results indicate that the binding of myosin to actin depends on the actin bundle shape, providing a feedback mechanism between the myosin activity and filament deformations for the self-organization of large motor filament assemblies.

Unusual cause of obstructive shock following esophagectomy: a case report

Obstructive shock usually has an intrathoracic origin, such as pneumothorax, pericardial tamponade or pulmonary embolism. We report a case of hemo- dynamic shock in a 74-year-old patient four days after esophagectomy, just after the start of mechanical ventilation for bilateral pneumonia. The sudden onset of severe abdominal distension and the presence of air in the intra-abdominal drain suggested tension pneumoperitoneum, confirmed by radiography. No pneumothorax was associated. Urgent decompression was required to improve hemodynamics. Perforation of the gastrointestinal tract was ruled out. The cause was a bronchopleural fistula opened by mechanical ventilation. Rarely, cardiorespiratory failure may occur after tension pneumoperitoneum by reducing lung volume and cardiac preload, similar to obstructive shock from the usual intrathoracic causes or acting as an abdominal compartment syndrome (ACS). Its recognition and abdominal decompression are key steps in the patient’s recovery. Tension pneumoperitoneum related to mechanical ventilation and airway injury without associated pneumothorax is exceptional and, to our knowledge, has never been reported as a postoperative complication of esophagectomy.

Identification of TB space-time clusters and hotspots in Ouest département, Haiti, 2011-2016

BACKGROUND

Haiti has the highest incidence rate of TB in the Western Hemisphere, with an estimated 170 cases per 100,000 in 2019. Since 2010, control efforts have focused on targeted case-finding activities in urban areas, implementation of rapid molecular diagnostics at high-volume TB centers, and improved reporting. TB analyses are rarely focused on lower geographic units; thus, the major goal was to determine if there were focal areas of TB transmission from 2011 to 2016 at operational geographic levels useful for the National TB Control Program (PNLT).

METHODS

We created a geocoder to locate TB cases at the smallest geographic level. Kulldorff's space-time permutation scan, Anselin Moran's I, and Getis-Ord Gi* statistics were used to determine the spatial distribution and clusters of TB.

RESULTS

With 91% of cases linked using the geocoder, TB clusters were identified each year. Getis-Ord Gi* analysis revealed 14 distinct spatial clusters of high incidences in the Port-au-Prince metropolitan area. One hundred retrospective space-time clusters were detected.

CONCLUSION

Our study confirms the presence of TB hotspots in the Ouest département, with most clusters in the Port-au-Prince metropolitan area. Results will help the PNLT and its partners better design case-finding strategies for these areas.

Introducing new and repurposed TB drugs: the endTB experience

In 2015, the initiative Expand New Drug Markets for TB (endTB) began, with the objective of reducing barriers to access to the new and repurposed TB drugs. Here we describe the major implementation challenges encountered in 17 endTB countries. We provide insights on how national TB programmes and other stakeholders can scale-up the programmatic use of new and repurposed TB drugs, while building scientific evidence about their safety and efficacy. For any new drug or diagnostic, multiple market barriers can slow the pace of scale-up. During 2015-2019, endTB was successful in increasing the number of patients receiving new and repurposed TB drugs in 17 countries. The endTB experience has many lessons, which are relevant to country level introduction of new TB drugs, as well as non-TB drugs and diagnostics. For example: the importation of TB drugs is possible even in the absence of registration; emphasis on good clinical monitoring is more important than pharmacovigilance reporting; national guidelines and expert committees can both facilitate and hinder innovative practice; clinicians use new and repurposed TB drugs when they are available; data collection to generate scientific evidence requires financial and human resources; pilot projects can drive national scale-up.

Producing three-dimensional printed models of the hepatobiliary system from computed tomography imaging data

INTRODUCTION

Macroscopic anatomy has traditionally been taught using cadaveric material, lectures and a variety of additional resources including online modules and anatomical models. Traditional plastic models are effective educational tools yet they have significant drawbacks such as a lack of anatomical detail, a lack of texturisation and cost. Three-dimensional printed models stand to solve these problems and widen access to high-quality anatomical teaching. This paper outlines the use of three-dimensional multiplanar imaging (computed tomography) in the development of an accurate model of the hepatobiliary system.

MATERIALS AND METHODS

Computed tomography scans were used to construct a virtual three-dimensional model of the hepatobiliary system. This was printed locally as a full-size colour model. We give a complete account of the process and software used.

DISCUSSION

This study is among the first of a series in which we will document the newly formed Oxford Library of Anatomy. This series will provide the methodology for the production of three-dimensional models from computed tomography and magnetic resonance imaging scans, and the library will provide a complete collection of the most complex anatomical areas. We hope that these models will form an important adjunct in teaching anatomy to medical students and surgical trainees.

Feasibility of the single-incision subxiphoid approach for video-assisted thoracoscopic surgery in dogs

OBJECTIVES

To report early results of uniportal video-assisted thoracoscopic surgery in dogs using a single-incision subxiphoid approach.

MATERIALS AND METHODS

Retrospective study of 10 client-owned dogs with: pyothorax (n=5), pericardial effusion (n=2), bilateral pneumothorax (n=1), retained surgical swab (n=1), cranial mediastinal mass (n=1). With the dog in dorsal recumbency a 3-4 cm incision was made over the xiphoid process. After resection of the xiphoid process, a tunnel was created towards the pleura and open access maintained with an Alexis™ wound retractor. The pleural cavity was explored with a 10 mm 30° or 5 mm 0° telescope and straight laparoscopic instruments.

RESULTS

Median surgical time was 75 minutes. The SISA technique was performed successfully in five of 10 cases and allowed easy and adequate inspection of the intra-thoracic structures. One case was converted to lateral thoracotomy after laceration of the vena cava and one converted to median sternotomy because of adhesions. An additional port was placed in three cases to facilitate triangulation and surgical manipulation. No other intra-operative complications were encountered.

CLINICAL SIGNIFICANCE

In this initial report of uniportal thoracic approach in dogs, this technique allowed excellent access and treatment of mediastinal structures. Further cases are required to assess its suitability for pulmonary surgery.

Active cargo positioning in antiparallel transport networks

Cytoskeletal filaments assemble into dense parallel, antiparallel, or disordered networks, providing a complex environment for active cargo transport and positioning by molecular motors. The interplay between the network architecture and intrinsic motor properties clearly affects transport properties but remains poorly understood. Here, by using surface micropatterns of actin polymerization, we investigate stochastic transport properties of colloidal beads in antiparallel networks of overlapping actin filaments. We found that 200-nm beads coated with myosin Va motors displayed directed movements toward positions where the net polarity of the actin network vanished, accumulating there. The bead distribution was dictated by the spatial profiles of local bead velocity and diffusion coefficient, indicating that a diffusion-drift process was at work. Remarkably, beads coated with heavy-mero-myosin II motors showed a similar behavior. However, although velocity gradients were steeper with myosin II, the much larger bead diffusion observed with this motor resulted in less precise positioning. Our observations are well described by a 3-state model, in which active beads locally sense the net polarity of the network by frequently detaching from and reattaching to the filaments. A stochastic sequence of processive runs and diffusive searches results in a biased random walk. The precision of bead positioning is set by the gradient of net actin polarity in the network and by the run length of the cargo in an attached state. Our results unveiled physical rules for cargo transport and positioning in networks of mixed polarity.

Loss to follow-up among patients receiving anti-tuberculosis treatment, Haiti, 2011-2015

Setting: Tuberculosis (TB) treatment facilities in Haiti. Objective: To assess factors associated with loss to follow-up (LTFU) among patients receiving treatment for tuberculosis (TB) in Haiti. Design: We analyzed Haiti's national surveillance data for patients started on anti-tuberculosis treatment from 2011 to 2015 to determine factors associated with LTFU using multivariable logistic regression and describe LTFU in terms of subnational units to target future intervention strategies. We also conducted a survival analysis to estimate hazard ratios of factors associated with time to LTFU. Results: Of 81 490 TB cases reported, 7423 (9.1%) were LTFU during anti-tuberculosis treatment, increasing from 7.1% in 2011 to 10.3% in 2015. Six high-volume facilities had significantly higher rates of LTFU (14.3-31.9%) than the rest of the country, accounting for 18.8% of all TB cases reported, but 41.7% of all LTFU patients. Male sex, previous treatment history, and human immunodeficiency virus infection were associated with higher rates of LTFU. The median time to LTFU was 94 days. Conclusion: A small number of facilities accounted for disproportionately high rates of LTFU. These results identify characteristics of facilities and individuals leading to concentrated interventions to reduce LTFU and improve treatment success.

Downregulation of heat shock protein B8 decreases osteogenic differentiation potential of dental pulp stem cells during in vitro proliferation

OBJECTIVES

Tissue-derived stem cells, such as dental pulp stem cells (DPSCs), reduce differentiation capability during in vitro culture. We found that cultured DPSCs reduce expression of heat shock protein B8 (HspB8) and GIPC PDZ domain containing family member 2 (Gipc2). Our objectives were to evaluate the changes in DPSC composition during in vitro proliferation and to determine whether HspB8 and Gipc2 have function in differentiation potential of DPSCs.

MATERIALS AND METHODS

Different passages of rat DPSCs were evaluated for changes in CD90+ and/or CD271+ stem cells and changes in osteogenic potential. Real-time RT-PCR and immunostaining were conducted to determine expression of HspB8 and Gipc2. Expression of the genes in DPSCs was knocked down by siRNA, followed by osteogenic induction to evaluate the function of the genes.

RESULTS

About 90% of cells in the DPSC cultures were CD90+ and/or CD271+ cells without dramatic change during in vitro proliferation. The DPSCs at passages 3 to 5 (P3 to P5) possess strong osteogenic potential, but such potential was greatly reduced at later passages. Expression of HspB8 and Gipc2 was significantly reduced at P11 versus P3. Knock-down of HspB8 expression abolished osteogenic potential of the DPSCs, but knock-down of Gipc2 had no effect.

CONCLUSIONS

CD90+ and CD271+ cells are the major components of DPSCs in in vitro culture. High-level expression of HspB8 was critical for maintaining differentiation potential of DPSCs.

Strain-Gradient Position Mapping of Semiconductor Quantum Dots

We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35  nm down to ±1  nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.