Stretching of porous poly (l-lactide-co-ε-caprolactone) membranes regulates the differentiation of mesenchymal stem cells

Background: Among a variety of biomaterials supporting cell growth for therapeutic applications, poly (l-lactide-co-ε-caprolactone) (PLCL) has been considered as one of the most attractive scaffolds for tissue engineering owing to its superior mechanical strength, biocompatibility, and processibility. Although extensive studies have been conducted on the relationship between the microstructure of polymeric materials and their mechanical properties, the use of the fine-tuned morphology and mechanical strength of PLCL membranes in stem cell differentiation has not yet been studied.Methods: PLCL membranes were crystallized in a combination of diverse solvent–nonsolvent mixtures, including methanol (MeOH), isopropanol (IPA), chloroform (CF), and distilled water (DW), with different solvent polarities. A PLCL membrane with high mechanical strength induced by limited pore formation was placed in a custom bioreactor mimicking the reproducible physiological microenvironment of the vascular system to promote the differentiation of mesenchymal stem cells (MSCs) into smooth muscle cells (SMCs).Results: We developed a simple, cost-effective method for fabricating porosity-controlled PLCL membranes based on the crystallization of copolymer chains in a combination of solvents and non-solvents. We confirmed that an increase in the ratio of the non-solvent increased the chain aggregation of PLCL by slow evaporation, leading to improved mechanical properties of the PLCL membrane. Furthermore, we demonstrated that the cyclic stretching of PLCL membranes induced MSC differentiation into SMCs within 10 days of culture.Conclusion: The combination of solvent and non-solvent casting for PLCL solidification can be used to fabricate mechanically durable polymer membranes for use as mechanosensitive scaffolds for stem cell differentiation

Actin cap associated focal adhesions and their distinct role in cellular mechanosensing

The ability for cells to sense and adapt to different physical microenvironments plays a critical role in development, immune responses, and cancer metastasis. Here we identify a small subset of focal adhesions that terminate fibers in the actin cap, a highly ordered filamentous actin structure that is anchored to the top of the nucleus by the LINC complexes; these differ from conventional focal adhesions in morphology, subcellular organization, movements, turnover dynamics, and response to biochemical stimuli. Actin cap associated focal adhesions (ACAFAs) dominate cell mechanosensing over a wide range of matrix stiffness, an ACAFA-specific function regulated by actomyosin contractility in the actin cap, while conventional focal adhesions are restrictively involved in mechanosensing for extremely soft substrates. These results establish the perinuclear actin cap and associated ACAFAs as major mediators of cellular mechanosensing and a critical element of the physical pathway that transduce mechanical cues all the way to the nucleus

Fast adaptation of activity sensing policies in mobile devices

Ministry of Education, Singapore under its Academic Research Funding Tier 2; Tier

Intramuscular Hemangioma Mimicking Myofascial Pain Syndrome : A Case Report

Intramuscular hemangioma, an infrequent but important cause of musculoskeletal pain, is often difficult to establish the diagnosis clinically. This report describes a case of a 32-yr-old woman who presented with severe left calf pain for 10 yr. Initial conservative treatments consisting of intramuscular electrical stimulation, herb medication, acupuncture, and intramuscular lidocaine injection under the diagnosis of myofascial pain syndrome in other facilities, failed to alleviate the symptoms. On physical examination, there was no motor weakness or sensory change. Conventional radiography of the leg revealed a soft tissue phlebolith. Conventional angiography study showed hemangioma. Intramuscular hemangioma within the soleus muscle was confirmed by magnetic resonance imaging. Following surgical excision of the hemangioma, the patient's symptom resolved completely. Intramuscular hemangioma is a rare cause of calf pain and should be considered in the differential diagnosis if a patient with muscle pain, particularly if associated with a soft tissue mass, fails to respond to conservative treatment

Diagnosis of Pure Ulnar Sensory Neuropathy Around the Hypothenar Area Using Orthodromic Inching Sensory Nerve Conduction Study: A Case Report

Ulnar neuropathy at the wrist is an uncommon disease and pure ulnar sensory neuropathy at the wrist is even rarer. It is difficult to diagnose pure ulnar sensory neuropathy at the wrist by conventional methods. We report a case of pure ulnar sensory neuropathy at the hypothenar area. The lesion was localized between 3 cm and 5 cm distal to pisiform using orthodromic inching test of ulnar sensory nerve to stimulate at three points around the hypothenar area. Ultrasonographic examination confirmed compression of superficial sensory branch of the ulnar nerve. Further, surgical exploration reconfirmed compression of the ulnar nerve. This case report demonstrates the utility of orthodromic ulnar sensory inching test

Biodegradable, flexible silicon nanomembrane-based NO x gas sensor system with record-high performance for transient environmental monitors and medical implants

Abstract: A novel transient electronics technology that is capable of completely dissolving or decomposing in certain conditions after a period of operation offers unprecedented opportunities for medical implants, environmental sensors, and other applications. Here, we describe a biodegradable, flexible silicon-based electronic system that detects NO species with a record-breaking sensitivity of 136 Rs (5 ppm, NO2) and 100-fold selectivity for NO species over other substances with a fast response (~30 s) and recovery (~60 s). The exceptional features primarily depend on not only materials, dimensions, and design layouts but also temperatures and electrical operations. Large-scale sensor arrays in a mechanically pliable configuration exhibit negligible deterioration in performance under various modes of applied loads, consistent with mechanics modeling. In vitro evaluations demonstrate the capability and stability of integrated NOx devices in severe wet environments for biomedical applications

Heart Transplantation in Pediatric Patients: Twelve-Year Experience of the Asan Medical Center

Heart transplantation is a standard treatment for end-stage heart disease. Pediatric heart transplantation, however, is not frequently performed due to the shortage of pediatric heart donors. This is the first report of pediatric heart transplantation in Korea. Our retrospective study included 37 patients younger than 18 yr of age who underwent heart transplantation at Asan Medical Center between August 1997 and April 2009. Preoperative diagnosis was either cardiomyopathy (n = 29, 78.3%) or congenital heart disease (n = 8, 22.7%). Mean follow up period was 56.9 ± 44.6 months. There were no early death, but 7 late deaths (7/37, 18.9%) due to rejection after 11, 15, 41 months (n = 3), infection after 5, 8, 10 months (n = 3), suspicious ventricular arrhythmia after 50 months (n = 1). There was no significant risk factor for survival. There were 25 rejections (25/37, 67.6%); less than grade II occurred in 17 patients (17/25, 68%) and more than grade II occurred in 8 patients (8/25, 32%). Actuarial 1, 5, and 10 yr survival was 88.6%, 76.8%, and 76.8%. Our midterm survival of pediatric heart transplantation showed excellent results. We hope this result could be an encouraging message to do more pediatric heart transplantation in Korean society