Irregular Defects Research Articles

Effect of decellularized adipose tissue particle size and cell density on adipose-derived stem cell proliferation and adipogenic differentiation in composite methacrylated chondroitin sulphate hydrogels

An injectable composite scaffold incorporating decellularized adipose tissue (DAT) as a bioactive matrix within a hydrogel phase capable of in situ polymerization would be advantageous for adipose-derived stem cell (ASC) delivery in the filling of small or irregular soft tissue defects. Building on previous work, the current study investigates DAT milling methods and the effects of DAT particle size and cell seeding density on the response of human ASCs encapsulated in photo-cross-linkable methacrylated chondroitin sulphate (MCS)—DAT composite hydrogels. DAT particles were generated by milling lyophilized DAT and the particle size was controlled through the processing conditions with the goal of developing composite scaffolds with a tissue-specific 3D microenvironment tuned to enhance adipogenesis. ASC proliferation and adipogenic differentiation were assessed in vitro in scaffolds incorporating small (average diameter of 38 ± 6 μm) or large (average diameter of 278 ± 3 μm) DAT particles in comparison to MCS controls over a period of up to 21 d. Adipogenic differentiation was enhanced in the composites incorporating the smaller DAT particles and seeded at the higher density of 5 × 105 ASCs/scaffold, as measured by glycerol-3-phosphate dehydrogenase (GPDH) enzyme activity, semi-quantitative analysis of perilipin expression and oil red O staining of intracellular lipid accumulation. Overall, this study demonstrates that decellularized tissue particle size can impact stem cell differentiation through cell–cell and cell–matrix interactions, providing relevant insight towards the rational design of composite biomaterial scaffolds for adipose tissue engineering.

Effect of a new bioactive fibrous glassy scaffold on bone repair.

Researchers have investigated several therapeutic approaches to treat non-union fractures. Among these, bioactive glasses and glass ceramics have been widely used as grafts. This class of biomaterial has the ability to integrate with living bone. Nevertheless, bioglass and bioactive materials have been used mainly as powder and blocks, compromising the filling of irregular bone defects. Considering this matter, our research group has developed a new bioactive glass composition that can originate malleable fibers, which can offer a more suitable material to be used as bone graft substitutes. Thus, the aim of this study was to assess the morphological structure (via scanning electron microscope) of these fibers upon incubation in phosphate buffered saline (PBS) after 1, 7 and 14 days and, also, evaluate the in vivo tissue response to the new biomaterial using implantation in rat tibial defects. The histopathological, immunohistochemistry and biomechanical analyzes after 15, 30 and 60 days of implantation were performed to investigate the effects of the material on bone repair. The PBS incubation indicated that the fibers of the glassy scaffold degraded over time. The histological analysis revealed a progressive degradation of the material with increasing implantation time and also its substitution by granulation tissue and woven bone. Histomorphometry showed a higher amount of newly formed bone area in the control group (CG) compared to the biomaterial group (BG) 15 days post-surgery. After 30 and 60 days, CG and BG showed a similar amount of newly formed bone. The novel biomaterial enhanced the expression of RUNX-2 and RANK-L, and also improved the mechanical properties of the tibial callus at day 15 after surgery. These results indicated a promising use of the new biomaterial for bone engineering. However, further long-term studies should be carried out to provide additional information concerning the material degradation in the later stages and the bone regeneration induced by the fibrous material.

The Changes of Absorption and Catalytic Capacity on Reduced Graphene Oxide After Electron Beam Irradiation

As is well-known, porous nanomaterials have attracted increasing attention recently, and graphene-related materials (such as porous graphene) have been studied both experimentally and theoretically. Almost all researches are focused on nanoelectronics, supercapacitors, multifunctional membrances, bio-applications or others. Consequently, in order to understand the differences between porous graphene and normal graphene at adsorption and catalytic property, in this experiment, with the removal of metal ion (152 Eu(III) ) and organic matter (gallic acid) and reduction of 4-nitrophenol (4-NP) by NaBH 4 as model reactions, a systematic investigation into the adsorptive performance as well as catalytic activity of graphene with or without electron beam irradiation exposure had been carried out. As the results showed, compared with the reduction of pristine graphene oxidized (R-GO), the reduction of graphene oxidized with electron beam irradiation exposure (100 MGy, about 2 h, radiation graphene oxide (R-RGO)) had many irregular defects caused by lack of atoms; the adsorptive performance of the R-RGO increased for metals but decreased for organic matter. However, the adsorption rate of the R-RGO was lower for metals, but higher for organic matter than that of the R-GO. In addition, the results also showed that the R-RGO had a better catalytic capacity than the R-GO.

Staple-line recurrence arising 10years after functional end-to-end anastomosis for colon cancer: a case report.

We report a rare case of late staple-line recurrence arising 10 years after functional end-to-end anastomosis for splenic flexure colon cancer. An 80-year-old man, who underwent partial colectomy with functional end-to-end anastomosis for splenic flexure colon cancer 10 years earlier, presented with a chief complaint of anorexia. Complete blood count showed anemia, and the fecal occult blood test was positive. Lower gastrointestinal series showed an irregular defect of the splenic flexure, and colonoscopy showed an ulcerated tumor on the staple line of the primary surgery. Partial colectomy was performed, and the tumor was pathologically diagnosed as moderately differentiated tubular adenocarcinoma, resembling the pathology of primary colon cancer. This case suggests the importance of considering staple-line recurrence after functional end-to-end anastomosis for colon cancer even more than 5 years after primary surgery.

Three dimensional plotted extracellular matrix scaffolds using a rapid prototyping for tissue engineering application

Naturally derived biomaterials are rarely used in advanced rapid prototyping technology despite their superior biocompatibility. The main problem of natural material plotting is the high sensitivity of materials concentration and viscosity on the plotting nozzle. The aim of the current study was to develop a three dimensional (3D) plotting system capable of dispensing extracellular matrix (ECM)-c (ECM powder blended collagen) and manufacture various shapes of ECM-c scaffolds to apply for irregular defects. We had adapted a powder-based plotting approach to print the stable 3D construct using only cartilage derived ECM materials. This study successfully developed the plotting method for high viscous ECM-c material and showed the 3D plotted scaffolds with high interconnected pores as well as complex shape. Furthermore, cell culture results proved that plotted ECM-c scaffolds were able to provide a suitable environment for cell attachment, proliferation and chondrogenesis. This study shows the 3D printing feasibility of ECM natural material has demonstrated as a first time. We believe our results will offer a meaningful step toward the 3D scaffold printing based on natural ECM materials for future organ printing.

Surgical Treatment of a Chronic Brain Abscess and Growing Skull Fracture in a Dog

A 2-year-old female spayed Miniature Dachshund was presented for seizures and right prosencephalic signs. A multiloculated, ring-enhancing mass in the right cerebrum associated with dilation of the right lateral ventricle and brain herniation was seen on magnetic resonance imaging. An irregular calvarial defect with smoothly scalloped edges was seen overlying the mass on computed tomography. The mass was removed via craniectomy and was diagnosed as a chronic brain abscess caused byPeptostreptococcus anaerobius. The patient was maintained on antibiotics for 12 weeks. Follow-up MRI performed 14 weeks after surgery confirmed complete removal of the abscess as well as a contrast-enhancing collection of extra-axial material consistent with a chronic subdural hematoma. The neurologic abnormalities, including seizures, have improved in the 44 months since surgery. Brain abscesses in dogs can have an insidious clinical course prior to causing serious neurologic deterioration. Ventricular entrapment by an intracranial mass can contribute to acute neurologic decline. If surgically accessible, outcome following removal of a brain abscess can be excellent; aerobic and anaerobic bacterial culture should be performed in these cases. Subdural hematoma can occur following removal of a large intracranial mass. Growing skull fractures can occur in dogs but may not require specific surgical considerations.

Ectopic osteogenesis of an injectable nHAC/CSH loaded with blood-acquired mesenchymal progenitor cells in a nude mice model.

An injectable bone cement, nHAC/CSH, which consists of nano-hydroxyapatite/collagen (nHAC) and calcium sulphate hemihydrate (CaSO4.½H2O; CSH) was investigated as a tissue-engineered scaffold material with blood-acquired mesenchymal progenitor cells (BMPCs) as seeding cells. An in vitro study on the cytocompatability of nHAC/CSH and an in vivo study on the ectopic bone formation of nHAC/CSH loaded with dBMPCs were both conducted. The dBMPCs morphology, proliferation, differentiation and apoptosis assays were conducted using the direct contact and extract method. The cells tests exhibited normal growth and bioactive function in vitro. Studies in vivo showed that this injectable tissue engineered bone (ITB) formed bone structure in the heterotopic site of nude mice. These findings indicate that the ITB composed of nHAC/CSH and dBMPCs may represent a useful strategy for clinical reconstruction of irregular bone defects.

A bioactive “self-fitting” shape memory polymer scaffold with potential to treat cranio-maxillo facial bone defects

While tissue engineering is a promising alternative for treating critical-sized cranio-maxillofacial bone defects, improvements in scaffold design are needed. In particular, scaffolds that can precisely match the irregular boundaries of bone defects as well as exhibit an interconnected pore morphology and bioactivity would enhance tissue regeneration. In this study, a shape memory polymer (SMP) scaffold was developed exhibiting an open porous structure and the capacity to conformally “self-fit” into irregular defects. The SMP scaffold was prepared via photocrosslinking of poly(ε-caprolactone) (PCL) diacrylate using a SCPL method, which included a fused salt template. A bioactive polydopamine coating was applied to coat the pore walls. Following exposure to warm saline at T>Ttrans (Ttrans=Tm of PCL), the scaffold became malleable and could be pressed into an irregular model defect. Cooling caused the scaffold to lock in its temporary shape within the defect. The polydopamine coating did not alter the physical properties of the scaffold. However, polydopamine-coated scaffolds exhibited superior bioactivity (i.e. formation of hydroxyapatite in vitro), osteoblast adhesion, proliferation, osteogenic gene expression and extracellular matrix deposition.

Injectable polymerized high internal phase emulsions with rapid in situ curing.

Polymerized high internal phase emulsions (polyHIPEs) have been utilized in the creation of injectable scaffolds that cure in situ to fill irregular bone defects and potentially improve tissue healing. Previously, thermally initiated scaffolds required hours to cure, which diminished the potential for clinical translation. Here, a double-barrel syringe system for fabricating redox-initiated polyHIPEs with dramatically shortened cure times upon injection was demonstrated with three methacrylated macromers. The polyHIPE cure time, compressive properties, and pore architecture were investigated with respect to redox initiator chemistry and concentration. Increased concentrations of redox initiators reduced cure times from hours to minutes and increased the compressive modulus and strength without compromising the pore architecture. Additionally, storage of the uncured emulsion at reduced temperatures for 6 months was shown to have minimal effects on the resulting graft properties. These studies indicate that the uncured emulsions can be stored in the clinic until they are needed and then rapidly cured after injection to rigid, high-porosity scaffolds. In summary, we have improved upon current methods of generating injectable polyHIPE grafts to meet translational design goals of long storage times and rapid curing (<15 min) without sacrificing porosity or mechanical properties.

Knot Impingement After Rotator Cuff Repair: Is It Real?

The purpose of this study was to compare morphologic features of the acromion after 2 different repair methods (single-row [SR] repair with a minimum of 4 knots and suture-bridge [SB] repair with minimal knots) in medium to large rotator cuff tears. From May 2005 to July 2012, 1,693 rotator cuff repairs were performed, among them medium to large tears requiring more than 2 anchors for repair; those who had 6-month postoperative magnetic resonance imaging (MRI) scans were included (221 shoulders). They were divided into 2 groups; group A (SR repair) and group B (SB repair). Acromial morphologic characteristics were evaluated using MRI 6 months postoperatively. An acromial defect was defined as an irregular defect or erosion on the flat acromion. Clinical measurements were performed using the American Shoulder and Elbow Surgeons (ASES) score, Constant score, visual analogue scale (VAS) pain score, and range of motion (ROM). Erosion in the acromion was observed in 2 of 118 patients (1.7%) in group A and in 1 of 103 (1%) patients in group B. There was no statistically significant difference between the 2 groups (P = .796). A statistically significant improvement was observed in the clinical scores measured (P = .0043). ROM was not fully recovered to the preoperative level at 6 months postoperatively. Acromioplasty was performed in 2 of 3 patients with acromial erosion. There was acromial erosion in one patient in group A without performing subacromial decompression. Our study showed that there was no difference in acromial erosion in high-profile knots made by an SR compared with double-row (DR) SB low-profile repairs. Level III, retrospective comparative study.

Reconstruction of the Irregular Shape Defects Using the Free Polyfoliate Perforator Flaps

Reconstruction of the Irregular Shape Defects Using the Free Polyfoliate Perforator Flaps

Various Types of Niche Imaging by Sonohysterography

: Cesarean scar defects (CSD) or niche are the myometrial discontinuity at the previous cesarean section scar region. We aimed to depict various types of niche imaging by sonohysterography. Recently, the rate of cesarean section delivery has markedly risen around the world; therefore, women with cesarean scar defects are increased and present in up to 19% of women post cesarean section. The increase of repeat cesarean section has been associated with an increase in complications in subsequent pregnancies such as scar pregnancy with life threatening bleeding, uterus rupture, placenta accreta and its subtypes and prolonged postmenstrual spotting. The deeper the niche (or the thinner the overlying myometrium), the higher the risk for complications in a subsequent pregnancy. Various shapes of uterine cesarean scar defects (niche) in TVS and SHG include: thin linear defect, wedge shape defect, droplet defect, semicircular defect, rectangle defect, inclusion cyst defect, irregular defect, multiple defects. Although the ability of transvaginal ultrasound (TVUS) to detect cesarean scars remains unknown, its higher frequency and proximity to the pelvic organs has been used as a powerful tool for detecting the uterine scar of a previous cesarean section. Recently with the increasing use of sonohysterography (SHG) (transvaginal ultrasound with saline infusion) detection of scar defect has been enhanced frequently.

Graphene: One Material, Many Possibilities—Application Difficulties in Biological Systems

Energetic technologies, nanoelectronics, biomedicine including gene therapy, cell imaging or tissue engineering are only few from all possible applications for graphene, the thinnest known carbon configuration and a basic element for other more complicated, better discovered and widely used nanostructures such as graphite, fullerenes and carbon nanotubes. The number of researches concerning graphene applications is rising every day which proves the great interest in its unique structure and properties. Ideal pristine graphene sheet presents a flat membrane of unlimited size with no imperfections while in practice we get different flakes with irregular edges and structural defects which influence the reactivity. Nanomaterials from graphene family differ in size, shape, layer number, lateral dimension, surface chemistry and defect density causing the existence of graphene samples with various influence on biological systems. Whether graphene induces cellular stress and activates apoptosis, or on the contrary facilitates growth and differentiation of the cells depends on its structure, chemical modifications and the growth process. A certain number of in vitro studies has indicated cytotoxic effects of graphene while the other show that it is safe. The diversity of the samples and methods of the production make it impossible to establish clearly the biological impact of graphene.

Composite hydrogel scaffolds incorporating decellularized adipose tissue for soft tissue engineering with adipose-derived stem cells

An injectable tissue-engineered adipose substitute that could be used to deliver adipose-derived stem cells (ASCs), filling irregular defects and stimulating natural soft tissue regeneration, would have significant value in plastic and reconstructive surgery. With this focus, the primary aim of the current study was to characterize the response of human ASCs encapsulated within three-dimensional bioscaffolds incorporating decellularized adipose tissue (DAT) as a bioactive matrix within photo-cross-linkable methacrylated glycol chitosan (MGC) or methacrylated chondroitin sulphate (MCS) delivery vehicles. Stable MGC- and MCS-based composite scaffolds were fabricated containing up to 5 wt% cryomilled DAT through initiation with long-wavelength ultraviolet light. The encapsulation strategy allows for tuning of the 3-D microenvironment and provides an effective method of cell delivery with high seeding efficiency and uniformity, which could be adapted as a minimally-invasive in situ approach. Through in vitro cell culture studies, human ASCs were assessed over 14 days in terms of viability, glycerol-3-phosphate dehydrogenase (GPDH) enzyme activity, adipogenic gene expression and intracellular lipid accumulation. In all of the composites, the DAT functioned as a cell-supportive matrix that enhanced ASC viability, retention and adipogenesis within the gels. The choice of hydrogel also influenced the cell response, with significantly higher viability and adipogenic differentiation observed in the MCS composites containing 5 wt% DAT. In vivo analysis in a subcutaneous Wistar rat model at 1, 4 and 12 weeks showed superior implant integration and adipogenesis in the MCS-based composites, with allogenic ASCs promoting cell infiltration, angiogenesis and ultimately, fat formation.

Adult-onset leukoencephalopathy, brain calcifications and cysts: a case report

IntroductionLeukoencephalopathy, brain calcifications and cysts, known as Labrune syndrome, is a rare syndrome. The etiology is unknown; in some cases it is difficult to differentiate from Coats plus syndrome and diagnosed as cerebroretinal microangiopathy with calcifications and cysts. We present the case of a patient with adult leukoencephalopathy, brain calcifications and cysts and discuss recently described entities in view of the relevant literature.Case presentationA previously healthy 19-year-old Chinese man presented with weakness of his right limbs that rapidly worsened over a short interval. Computed tomography and magnetic resonance imaging showed numerous low-density cysts, calcifications, and abnormal signal change of white matter. A visual field examination showed irregular visual field defects in both eyes. A neuro-ophthalmologic examination did not find evidence of Coats retinopathy. A larger excisional biopsy was carried out and a diagnosis of leukoencephalopathy, brain calcifications and cysts was confirmed.ConclusionsWe present an example of adult-onset leukoencephalopathy, brain calcifications and cysts and have expanded the clinical spectrum of features associated with this syndrome. Previous reports have not, to the best of our knowledge, previously reported visual field defects. Based on the latest findings, we believe that leukoencephalopathy, brain calcifications and cysts and Coats plus syndrome are genetically distinct entities.

The Volumetric Clipping for Industrial Computerized Tomography Based on CUDA

The fast development of the Graphics Processing Unit’s progammability and parallel computing power provides new solutions for visualization technology. As the carrier of volume date, a cubic box is selected as the bounding box in the improved ray-casting algorithm, whose diagonal vertex coordinates are stored in boxMin and boxMax respectively. By adjusting the two parameters we can change the shape of the bounding box and then choose the interesting region of the object, a CUDA based interactive volumetric clipping tool is finally realised. By changing the shape of bounding box, the axial volumetric clipping and arbitrary cross-section clipping are important ways to help to get the object's internal information. Experiments show this method is simple, efficient and useful especially for the irregular shape defect. In addition, even for the larger volume of data, we can get a high quality, cross-sectional images on a fast speed.

Forces Association-Based Active Contour

A welded structure must be inspected to guarantee that the weld quality meets the design requirements to assure safety and reliability. However, X-ray image analyses and defect recognition with the computer vision techniques are very complex. Most difficulties lie in finding the small, irregular defects in poor contrast images which requires pre processing to image, extract, and classify features from strong background noise. This paper addresses the issue of designing methodology to extract defect from noisy background radiograph with image processing. Based on the use of actives contours this methodology seems to give good results Keywords—Welding, Radiography, Computer vision, Active contour.

Relative survivability of human osteoblasts is enhanced by 39 °C and ascorbic acid after exposure to photopolymerization ingredients

Photopolymerizable hydrogels offer great potential in cartilage tissue engineering due to their ability to conform to irregular defect shapes and be applied in a potentially minimally invasive manner. An important process requirement in the use of photopolymerizable hydrogels is the ability of the suspended cells to withstand low intensity ultraviolet light (UV) exposure (4-5mW/cm(2)) and photoinitiator concentrations. For cartilage integration with underlying subchondral bone tissue, robust localized osteoblast activity is necessary. Yet, while it is known that osteoblasts do not respond well to UV light, limited work has been conducted to improve their survivability. In this study, we evaluated the cellular cytotoxicity of five different human cell sources at different UV exposure times, with and without a commercially used photoinitiator. We were able to confirm that human osteoblasts were the least tolerant to varying UV exposure times in comparison to bone marrow stem cell, periodontal ligament cell, smooth muscle and endothelial cell lineages. Moreover osteoblasts cultured at 39°C did not deteriorate in terms of alkaline phosphatase expression or calcium deposition within the extracellular matrix (ECM), but did reduce cell proliferation. We believe however that the lower proliferation diminished osteoblast sensitivity to UV and the photoinitiator. In fact, the relative survivability of osteoblasts was found to be augmented by the combination of a biochemical factor and an elevated incubation temperature; specifically, the use of 50mg/l of the anti-oxidant, ascorbic acid significantly (P<0.05) increased the survivability of osteoblasts when cultured at 39°C. We conclude that ascorbic acid at an incubation temperature of 39°C can be included in in vitro protocols used to assess cartilage integration with bone ECM. Such inclusion will enhance conditions of the engineered tissue model system in recapitulating in vivo osteoblast activity.

Ventricular Septal Avulsion and Ventricular Septal Defect After Blunt Trauma

Traumatic ventricular septal defect is an uncommon complication of blunt chest trauma. We report a case of ventricular septal avulsion, associated with traumatic ventricular septal defect and the associated management concerns.

Study on the Cavity Defects of Low-Pressure Lost Foam Casting for Magnesium Alloy

Cavity defects of low-pressure lost foam casting (LP-LFC) for magnesium alloy were investigated by using ladder samples and claviform samples.The physical feature of typical cavity defects of LP-LFC for magnesium castings had been tested by optical microscopy and scanning electron microscopy. And the chemical constitution of cavity surface was also tseted by energy spectrometer. The result indicated that the cluster cavity defects were formed with the application of higher vacuum at the metal-mold interface, which caused the liquid-EPS residue in the castings. Some irregular shape cavity defects were caused by slag entrapment or coating slough. These cavity defects could be avoided through reducing pouring temperature, filling velocity and vacuum level, improving the permeability of coating.