Benefits and risks of ventilator hyperinflation in mechanically ventilated intensive care patients: A systematic review and meta-analysis.

Objectives: Patients requiring mechanical ventilation in the intensive care unit (ICU) have diminished respiratory defences and are at high risk of respiratory compromise, leading to an increased risk of pulmonary infection and prolonged ventilation. Ventilator hyperinflation (VHI) is an airway clearance technique used by physiotherapists and is suggested to improve respiratory mechanics. The objective of this study was to review the evidence for the benefits and risks of VHI in intubated and mechanically ventilated patients in the ICU.

Perfusion decellularization of porcine esophagus: Study of two processing factors affecting the folded mucosal structure of the esophageal scaffold.

Acellular scaffolds from decellularized donor organs are showing promising clinical results in tissue and organ repair and regeneration. A successful decellularization process is determined by (a) its capability to decellularize complete organs of large animals, (b) retention of the extracellular matrix (ECM) structures and morphologies, and (c) minimal loss of ECM proteins. In this study, porcine esophagi were perfused in full thickness with 0.

Characterization, mechanical behavior and in vitro evaluation of a melt-drawn scaffold for esophageal tissue engineering.

Tubular esophageal scaffolds with fiber diameter ranging from 13.9±1.7μm to 65.

Regenerative medicine for oesophageal reconstruction after cancer treatment.

Removal of malignant tissue in patients with oesophageal cancer and replacement with autologous grafts from the stomach and colon can lead to problems. The need to reduce stenosis and anastomotic leakage after oesophagectomy is a high priority. Developments in tissue-engineering methods and cell-sheet technology have improved scaffold materials for oesophageal repair.

In vitro metal ion release and biocompatibility of amorphous Mg67Zn28Ca5 alloy with/without gelatin coating.

Amorphous zinc-rich Mg-Zn-Ca alloys have exhibited good tissue compatibility and low hydrogen evolution in vivo. However, suboptimal cell-surface interaction on magnesium alloy surface observed in vitro could lead to reduced integration with host tissue for regenerative purpose. This study aims to improve cell-surface interaction of amorphous Mg67Zn28Ca5 alloy by coating a gelatin layer by electrospinning.

Cryogenic electrospinning: proposed mechanism, process parameters and its use in engineering of bilayered tissue structures.

Background: Conventional electrospun scaffolds have very small pores, thus limiting cellular infiltration, tissue ingrowth and vascularization in tissue engineering applications. The cryogenic electrospinning process overcame the small pore size constraints found in conventional electrospun scaffolds.

Aim: The aim of this paper is to propose a mechanism for cryogenic electrospinning and how scaffold pore size can be controlled.

Repair of osteochondral defects with rehydrated freeze-dried oligo[poly(ethylene glycol) fumarate] hydrogels seeded with bone marrow mesenchymal stem cells in a porcine model.

Current surgical techniques for osteochondral injuries in young active patients are inadequate clinically. Novel strategies in tissue engineering are continuously explored in this area. Despite numerous animal studies that have shown encouraging results, very few large-scale clinical trials have been done to address this area of interest.

Continuous cell separation using dielectrophoresis through asymmetric and periodic microelectrode array.

The study presents a dielectrophoretic cell separation method via three-dimensional (3D) nonuniform electric fields generated by employing a periodic array of discrete but locally asymmetric triangular bottom microelectrodes and a continuous top electrode. Traversing through the microelectrodes, heterogeneous cells are electrically polarized to experience different strengths of positive dielectrophoretic forces, in response to the 3D nonuniform electric fields. The cells that experience stronger positive dielectrophoresis are streamed further in the perpendicular direction to the fluid flow, leaving the cells that experience weak positive dielectrophoresis, which continue to traverse the microelectrode array essentially along the laminar flow streamlines.

Oligo[poly(ethylene glycol)fumarate] hydrogel enhances osteochondral repair in porcine femoral condyle defects.

Background: Management of osteochondritis dissecans remains a challenge. Use of oligo[poly(ethylene glycol)fumarate] (OPF) hydrogel scaffold alone has been reported in osteochondral defect repair in small animal models. However, preclinical evaluation of usage of this scaffold alone as a treatment strategy is limited.

Esophageal tissue engineering: an in-depth review on scaffold design.

Treatment of esophageal cancer often requires surgical procedures that involve removal. The current approaches to restore esophageal continuity however, are known to have limitations which may not result in full functional recovery. In theory, using a tissue engineered esophagus developed from the patient's own cells to replace the removed esophageal segment can be the ideal method of reconstruction.

Cryogenic prototyping of chitosan scaffolds with controlled micro and macro architecture and their effect on in vivo neo-vascularization and cellular infiltration.

A major challenge in tissue engineering has been to develop scaffolds with controlled complex geometries, on both the macro- and micro-scale. One group of techniques, using rapid prototyping (RP) processes, has the capability to produce complex three-dimensional structures with good control over the size, geometry, and connectivity of the pores. In this article, a novel technique based on RP technology, that is, cryogenic prototyping (CP), that has the capability to fabricate scaffolds with controlled macro- and micro-structures, is presented.

Fabrication and in vitro and in vivo cell infiltration study of a bilayered cryogenic electrospun poly(D,L-lactide) scaffold.

Cryogenic electrospinning has previously been demonstrated for controlling the pore sizes of electrospun scaffolds, which has been impossible with traditional electrospinning processes. This article describes the application of the cryogenic technique to fabricate a bilayered electrospun poly(D,L-lactide) scaffold (BLES) in a single uninterrupted process. The resulting BLES consisted of a traditional electrospun (ES) fibrous layer with a dense pore area of 17 +/- 3 microm(2) adjacent to a cryogenic electrospun layer (CES) with a pore area of 3300 +/- 500 microm(2).

Dependence of alignment direction on magnitude of strain in esophageal smooth muscle cells.

The response of cells in vitro to mechanical forces has been the subject of much research using devices to exert controlled mechanical stimulation on cultured cells or isolated tissue. In this study, esophageal smooth muscle cells were seeded on flexible polyurethane membranes to form a confluent cell layer. The cells were then subjected to uniform cyclic stretch of varying magnitudes at a frequency of approximately five cycles per minute in a custom made mechatronic bioreactor, providing similar strains experienced in the in vivo mechanical environment of the esophagus.

Neuroglycopenia and adrenergic responses to hypoglycaemia: insights from a local epidemic of serendipitous massive overdose of glibenclamide.

Aims: Recently, an unlicensed aphrodisiac formulation originating from China known as 'Power 1 Walnut' penetrated the illicit markets of South East Asia including Singapore. Subsequent toxicological analyses revealed that each 'Power 1 Walnut' pill was illegally adulterated with two prescription drugs--sildenafil 1 mg (a PDE5 inhibitor) and glibenclamide 93-98 mg (a long-acting sulphonylurea). As the drug was peddled to numerous people, a local 'hypoglycaemia epidemic' ensued, of which a small cluster presented to our hospital with severe hypoglycaemia.

Effect of electrospun poly(D,L-lactide) fibrous scaffold with nanoporous surface on attachment of porcine esophageal epithelial cells and protein adsorption.

Electrospun scaffolds have been increasingly used in tissue engineering applications due to their size-scale similarities with native extracellular matrices. Their inherent fibrous features may be important in promoting cell attachment and proliferation on the scaffolds. In this study, we explore the technique of fabricating electrospun fibers with nano-sized porous surfaces and investigate their effects on the attachment of porcine esophageal epithelial cells (PEECs).

Adhesion dynamics of porcine esophageal fibroblasts on extracellular matrix protein-functionalized poly(lactic acid).

Effective attachment of esophageal cells on biomaterials is one important requirement in designing engineered esophagus substitute for esophageal cancer treatment. In this study, poly(lactic acid) (PLA) was subjected to surface modification by coupling extracellular matrix (ECM) proteins on its surface to promote cell adhesion. Two typical ECM proteins, collagen type I (COL) and fibronectin (FN), were immobilized on the PLA surface with the aid of glutaraldehyde as a cross linker between aminolyzed PLA and ECM proteins.

Three-dimensional finite element model of the two-layered oesophagus, including the effects of residual strains and buckling of mucosa.

This study was carried out to develop a two-layered finite element model of the oesophagus. The outer muscle and inner mucosal layer were constructed individually with different mechanical properties and zero-stress opening angles. With the model, two simulations were performed.

Finite element simulation of food transport through the esophageal body.

The peristaltic transport of swallowed material in the esophagus is a neuro-muscular function involving the nerve control, bolus-structure interaction, and structure-mechanics relationship of the tissue. In this study, a finite element model (FEM) was developed to simulate food transport through the esophagus. The FEM consists of three components, i.

Dual requirements of extracellular matrix protein and chitosan for inducing adhesion contact evolution of esophageal epithelia.

It has been recently shown that chitosan (CHI)/collagen prostheses induced epithelization at the esophagus site of animal model. However, little is known on the biophysical mechanisms of cell adhesion on CHI-based material pertaining to esophagus tissue engineering. In this study, the adhesion contact dynamics of porcine esophageal epithelial cells seeded on CHI surface is probed using confocal-reflectance interference contrast microscopy in conjunction with phase-contrast microscopy.

Silent uterine rupture in an unscarred uterus.

Objective: Uterine rupture is one of the most serious obstetric complications, with an increased risk of maternal and perinatal morbidity, and even mortality.

Case Report: A multiparous woman came to our labor room at 41 weeks of gestation for induction of labor due to being post-term and having a nonreactive nonstress test. She had no history of abdominal or gynecologic surgery.

Viscoelasticity of esophageal tissue and application of a QLV model.

The time-dependent mechanical properties of the porcine esophagus were investigated experimentally and theoretically. It was hypothesized that the viscoelasticity was quasilinear, i.e.

3D Mechanical properties of the layered esophagus: experiment and constitutive model.

The identification of a three dimensional constitutive model is useful for describing the complex mechanical behavior of a nonlinear and anisotropic biological tissue such as the esophagus. The inflation tests at the fixed axial extension of 1, 1.125, and 1.

Novel biophysical techniques for investigating long-term cell adhesion dynamics on biomaterial surfaces.

Cell adhesion on biomaterial surface is crucial for the regeneration and function of clinically viable cell and tissues. In turn, the cellular phenotypes, following the mechanochemical transduction of adherent cells on biomaterials, are directly correlated to the biophysical responses of cells. However, the lack of an integrated bio-analytical system for probing the cell-substrate interface poses significant obstacles to understanding the behavior of cells on biomaterial surface.

Esophageal epithelium regeneration on fibronectin grafted poly(L-lactide-co-caprolactone) (PLLC) nanofiber scaffold.

In order to mimic normal epithelium regeneration on synthetic scaffold in vitro, biodegradable elastic poly(l-lactide-co-caprolactone) (PLLC) was processed into nanofibrous scaffold using electrospinning technology. An adhesive protein, fibronectin (Fn), was grafted onto the scaffold fiber surface via a two-step reaction: polyester aminolysis followed by Fn coupling via glutaraldehyde. Tensile testing was performed to measure the effect of aminolysis on the scaffold mechanical properties.