Two techniques for the preparation of cell-scaffold constructs suitable for sinus augmentation: steps into clinical application.

The objective of this clinical trial was the analysis of 2 methods for engineering of autologous bone grafts for maxillary sinus augmentation with secondary implant placement. Group 1 (8 patients, 12 sinuses): cells of mandibular periosteum were cultured in a good manufacturing practice laboratory (2 weeks) with autologous serum and then transferred onto a collagen matrix. After another week, these composites were transplanted into the sinuses. In group 2A (2 patients, 3 sinuses), cells of maxillary bone were cultivated with autologous serum for 2 weeks, seeded onto natural bone mineral (NBM, diameter [Ø] = 8 mm) blocks, and cultivated for another 1.5 months. These composites were transplanted into the sinuses. Group 2B (control, 3 patients, 5 sinuses) received NBM blocks alone. In the course of implant placement 6 (group 1) and 8 (group 2) months later, core biopsy were taken. Clinical follow-up period was 1 to 2.5 years in group 1 and approximately 7 years in groups 2A and 2B. New vital bone was found in all cases at median densities of 38\% (n = 12) in group 1, 32\% in group 2A (n = 3), and 25\% in group 2B (n = 5). Differences between group 1 and 2B as well as 2A and 2B were statistically significant ( p = 0.025). No adverse effects were seen. All methods described were capable of creating new bone tissue with sufficient stability for successful implant placement

Novel multiple sclerosis susceptibility loci implicated in epigenetic regulation.

We conducted a genome-wide association study (GWAS) on multiple sclerosis (MS) susceptibility in German cohorts with 4888 cases and 10,395 controls. In addition to associations within the major histocompatibility complex (MHC) region, 15 non-MHC loci reached genome-wide significance. Four of these loci are novel MS susceptibility loci. They map to the genes L3MBTL3, MAZ, ERG, and SHMT1. The lead variant at SHMT1 was replicated in an independent Sardinian cohort. Products of the genes L3MBTL3, MAZ, and ERG play important roles in immune cell regulation. SHMT1 encodes a serine hydroxymethyltransferase catalyzing the transfer of a carbon unit to the folate cycle. This reaction is required for regulation of methylation homeostasis, which is important for establishment and maintenance of epigenetic signatures. Our GWAS approach in a defined population with limited genetic substructure detected associations not found in larger, more heterogeneous cohorts, thus providing new clues regarding MS pathogenesis

A genetic investigation of sex bias in the prevalence of attention-deficit/hyperactivity disorder

Background Attention-deficit/hyperactivity disorder (ADHD) shows substantial heritability and is 2-7 times more common in males than females. We examined two putative genetic mechanisms underlying this sex bias: sex-specific heterogeneity and higher burden of risk in female cases. Methods We analyzed genome-wide autosomal common variants from the Psychiatric Genomics Consortium and iPSYCH Project (20,183 cases, 35,191 controls) and Swedish populationregister data (N=77,905 cases, N=1,874,637 population controls). Results Genetic correlation analyses using two methods suggested near complete sharing of common variant effects across sexes, with rg estimates close to 1. Analyses of population data, however, indicated that females with ADHD may be at especially high risk of certain comorbid developmental conditions (i.e. autism spectrum disorder and congenital malformations), potentially indicating some clinical and etiological heterogeneity. Polygenic risk score (PRS) analysis did not support a higher burden of ADHD common risk variants in female cases (OR=1.02 [0.98-1.06], p=0.28). In contrast, epidemiological sibling analyses revealed that the siblings of females with ADHD are at higher familial risk of ADHD than siblings of affected males (OR=1.14, [95% CI: 1.11-1.18], p=1.5E-15). Conclusions Overall, this study supports a greater familial burden of risk in females with ADHD and some clinical and etiological heterogeneity, based on epidemiological analyses. However, molecular genetic analyses suggest that autosomal common variants largely do not explain the sex bias in ADHD prevalence

Simulated surgical workshops enhance medical school students’ preparation for clinical rotation

BackgroundA major focus of the medical school curriculum is to ensure medical students are well prepared prior to entering clinical rotations, which includes the compulsory surgical rotation.AimsThe objective of this research was to design and formally evaluate a set of real-life surgical workshops aimed at better preparing medical students for their clinical rotation in surgery. These workshops would be incorporated into the pre-clinical medical school curriculum.MethodDedicated surgical workshops were introduced into the preclinical component of the Bachelor of Medicine/Bachelor of Surgery (MBBS) program at our University in 2009. These workshops encompassed training in the clinical skills needed in the perioperative and wider hospital setting. A survey comprising of eight to nine ranked questions (utilising a five-point Likert Scale) as well as three short answer questions was administered to the medical students after they completed their compulsory surgical clinical rotation.ResultsThe overall response rate to the survey evaluating the surgical workshops was 79% (123/155). The mean of the ranked questions ranged from 4.05 to 4.89 which indicated that the students found the workshops useful. When evaluating the short answer questions (via topic coding), additional information was provided that supported and explained the survey findings and also included suggestions for improvements.ConclusionThe findings of the medical student survey demonstrated the value of incorporating dedicated preparatory surgical workshops in the medical school pre-clinical curriculum. However, further research is warranted to determine if this inclusion translated into improved student performance during the clinical surgical rotation

Nanospiderwebs:Artificial 3D Extracellular Matrix from Nanofibers by Novel Clinical Grade Electrospinning for Stem Cell Delivery

Novel clinical grade electrospinning methods could provide three-dimensional (3D) nanostructured biomaterials comprising of synthetic or natural biopolymer nanofibers. Such advanced materials could potentially mimic the natural extracellular matrix (ECM) accurately and may provide superior niche-like spaces on the subcellular scale for optimal stem-cell attachment and individual cell homing in regenerative therapies. The goal of this study was to design several novel "nanofibrous extracellular matrices" (NF-ECMs) with a natural mesh-like 3D architecture through a unique needle-free multi-jet electrospinning method in highly controlled manner to comply with good manufacturing practices (GMP) for the production of advanced healthcare materials for regenerative medicine, and to test cellular behavior of human mesenchymal stem cells (HMSCs) on these. Biopolymers manufactured as 3D NF-ECM meshes under clinical grade GMP-like conditions show higher intrinsic cytobiocompatibility with superior cell integration and proliferation if compared to their 2D counterparts or a clinically-approved collagen membrane.No Full Tex

Proliferation assessment of primary human mesenchymal stem cells on collagen membranes for guided bone regeneration

Abstract PURPOSE: Human mesenchymal stem cells (hMSCs) hold the potential for bone regeneration because of their self-renewing and multipotent character. The goal of this study was to evaluate the influence of collagen membranes on the proliferation of hMSCs derived from bone marrow. A special focus was set on short-term eluates derived from collagen membranes, as volatile toxic materials washed out from these membranes may influence cell behavior during the short time course of oral surgery. MATERIALS AND METHODS: The proliferation of hMSCs seeded directly on a collagen membrane (BioGide) was evaluated quantitatively using the cell proliferation reagent WST-1 (4-3-[4-iodophenyl]-2-[4-nitrophenyl]-2H-[5-tetrazolio]-1, 3--benzol-disulfonate) and qualitatively by scanning electron microscopy. Two standard biocompatibility tests, namely the lactate dehydrogenase and MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazoliumbromide) tests, were performed using hMSCs cultivated in eluates from membranes incubated for 10 minutes, 1 hour, or 24 hours in serum-free cell culture medium. The data were analyzed statistically. RESULTS: Scanning electron microscopy showed large numbers of hMSCs with well-spread morphology on the collagen membranes after 7 days of culture. The WST test revealed significantly better proliferation of hMSCs on collagen membranes after 4 days of culture compared to cells cultured on a cover glass. Cytotoxicity levels were low, peaking in short-term eluates and decreasing with longer incubation times. CONCLUSION: Porcine collagen membranes showed good biocompatibility in vitro for hMSCs. If maximum cell proliferation rates are required, a prewash of membranes prior to application may be useful.No Full Tex

Comparison of in vitro biocompatibility of NanoBone^® and BioOss^® for human osteoblasts

Introduction: Scaffolds for bone tissue engineering seeded with the patient's own cells might be used as a preferable method to repair bone defects in the future. With the emerging new technologies of nanostructure design, new synthetic biomaterials are appearing on the market. Such scaffolds must be tested in vitro for their biocompatibility before clinical application. However, the choice between a natural or a synthetic biomaterial might be challenging for the doctor and the patient. In this study, we compared the biocompatibility of a synthetic bone substitute, NanoBoneto the widely used natural bovine bone replacement material BioOss Material and methods: The in vitro behaviour of human osteoblasts on both materials was investigated. Cell performance was determined using scanning electron microscopy (SEM), cell vitality staining and four biocompatibility tests (LDH, MTT, WST, BrdU). Results: We found that both materials showed low cytotoxicity and good biocompatibility. The MTT proliferation test was superior for Nanobone Discussion: Both scaffolds caused only little damage to human osteoblasts and justify their clinical application. However, NanoBoneas able to support and promote proliferation of human osteoblasts slightly better than BioOssn our chosen test set-up. The results may guide doctors and patients when being challenged with the choice between a natural or a synthetic biomaterial. Further experiments are necessary to determine the comparison of biocompatibility in vivo.No Full Tex

Mass production of nanofibrous extracellular matrix with controlled 3D morphology for large-scale soft tissue regeneration

Aim: Biomaterials that mimic the nanofibrous architecture of the natural extracellular matrix (ECM) are in the focus for stem cell hosting or delivery in tissue engineering of multilayered soft tissues such as skin, mucosa, or retina. Synthetic nanofibers for such ECM are usually produced by single-syringe electrospinning with only one needle-jet at very low production rates of 0.005-0.008?g筩n(-1). The aim of this study was to utilize a novel industrial needle-free multijet electrospinning device with the potential for mass production of nanofibrous ECM (NF-ECM) exhibiting a controlled three-dimensional (3D) morphology for large-scale applications such as large area skin regeneration in patients with burns. Methods: The novel NanoSpider頎S200, an industrial apparatus originally designed for electrospinning of nanofibrous textile meshes, was used to fabricate 3D NF-ECMs of the following synthetic and natural biopolymers: collagen, gelatin, poly(caprolactone) (PCL), and poly(l-lactide-co-glycolide) (PLGA). Different concentrations of Gelatin polymer solution were electrospun under varying processing conditions, namely speed of spinning electrode rotation (u) and electric field intensity (E) by altering applied voltage (v) or the distance between electrodes (h) to achieve homogeneous desirable 3D morphology. Nanofiber diameters were assessed by scanning electron microscopy (SEM). Biocompatibility was tested by WST-1 (water-soluble tetrazolium salt) proliferation assay of seeded human mesenchymal stem cells (HMSCs). Biological performance of HMSCs on 3D PLGA NF-ECM was compared to two-dimensional (2D) PLGA film controls via SEM and confocal microscopy. Western blotting addressed the expression of surface adhesion proteins; focal adhesion kinase (FAK), phosphorylated FAK (pY397), a-tubulin, paxillin, vinculin. and integrin subunits; a5, av, and ߱ proteins. Results: Large-scale mass production of NF-ECM membranes with a highly homogenous nanofiber morphology and 3D architecture could be produced with an extremely high production rate of 0.394ᰮ013?g筩n(-1)筨-1) when compared to standard procedures. This was achieved by electrospinning a 20% (wt)/(v) gelatin solution, in an electric field intensity of 0.381?kV筭(-1). The nanofibers possessed diameters of around 180ᴰ?nm with 28% deviation. HSMCs proliferation was significantly improved on NF-ECMs derived from collagen, gelatin, and PLGA when compared to PCL or flat coverglass controls (p<0.01). PLGA NF-ECM in 3D nanofibrous architecture possessed significantly superior biocompatibility when compared to flat 2D PLGA film (p<0.05). Furthermore, on 3D PLGA NF-ECMs, HSMCs expressed a higher amount of a-tubulin and paxillin compared to the HMSCs cultured on a 2D PLGA film (p<0.05). HMSCs exhibited a complex multifaceted morphology on all NF-ECMs, where cells appeared to be integrated into the 3D NF-ECMs niches with complex cell filopodia extending into to all directions. In contrast, HMSCs on flat 2D films of the same materials or on coverglass displayed a simple flattened, monolayered structure. Conclusion: Needle-free multijet electrospinning can be used to mass produce artificial ECMs with intrinsic biocompatibility and desirable integration of stem cells for large-scale applications.No Full Tex