Transforming Growth Factor Beta (TGF-β): Natural Curing Agents for Repair

yesThere are various techniques to enhance tissue regeneration via the application of growth factors to the site of regeneration to induce cells to proliferate, differentiate and regenerate. Generally, direct application of growth factors has little effect [1] because the growth factor diffuses out from the site of regeneration very quickly. This is a problem that can be solved by a controlled release of growth factor at the site of action over a long period of time by use of a bioabsorbable scaffold. Growth factors are protein based molecules in the body which are produced by cells and attach to the cell surface. Growth factors bind to membrane receptors, which in turn activate an intracellular signalling pathway. This will activate or inhibit a gene causing either an up regulation or down regulation of a gene product, which then alters the cells behaviour

Electrocardiography, ECG Interpretation and Applications

yesThe aim of this book is to be able to interpret Electrocardiograms avoiding all possible errors. The accuracy of the interpretation is of great importance but a true diagnosis is far more significant. This book focuses on the recognition and interpretation of arrhythmias, one of the most important clinical tools in medicine. The greatest degree of accuracy is achieved by familiarising with the normal ECG that enables the recognition of abnormal patterns to be made immediately. Firstly, it is necessary to acquaint the function of the heart and the electrical activity in order to broaden our understanding of how the ECG detects this electrical activity. It is essential to know the characteristic patterns of a normal ECG and to categorise a wide array of morphologic patterns along with determining abnormal ECG patterns to be diagnostic of particular pathological entities. A series of practical experiments have been carried out on various subjects using the BIOPAC system to record electrical signals of the heart. Subjects were asked to perform various tasks such as lying down, sitting, deep breathing and exercising to detect electrical signals in different conditions and eventually interpret the data. The ethical issue toward each subject is also too important, so it was necessary to let the subject know about any risk factors during experiment. For this purpose, a Volunteer Information Sheet was designed during this work for each subject to read and be aware of all the ethical issues. Also, another Patient Consent Form was designed to make sure that each volunteer fully understands the procedures. Volunteer Questionnaire is necessary to make sure volunteer that there is no problem, which can affect the experimental results. Finally, ECG results were interpreted using a systematic approach and the precise findings were correlated with the pathophysiology and clinical status of the patient. This book concludes with a thorough investigation into the essential techniques and skills required to accurately interpret an ECG, eliminating as many errors as possible

Cell engineering of human bone monolayers and the effect of growth factors and microcontact printed ECM proteins on wound healing. The role of ECM proteins, TGF¿-1, 2 and 3 and HCl/BSA in cellular adhesion, wound healing and imaging of the cell surface interface with the widefield surface plasmon microscope.

Bone repair is modulated by different stimuli. There is evidence that the Transforming Growth Factor-beta (TGF-¿) super-family of cytokines have significant effects on bone structure by regulating the replication and differentiation of chondrocytes, osteoblasts and osteoclasts. There is also significant evidence that interactions with extracellular matrix molecules also influence cell behaviour. This study aimed at determining the role of the TGF-¿s, Collagen type I, Fibronectin and Laminin in bone cell behaviour. To do this MG63 bone cells were used to examine cell adhesion and alignment to different micro-contact printed ECM protein patterns of different widths. The study also aimed at examining how TGF-¿1, 2 and 3 and their solvent and carrier (HCl and BSA, respectively) effected cell surface interactions, cell morphology, cell proliferation and integrin expression. Finally, this study also aimed at examining how the TGF-¿s and their solvent and carrier influenced wound closure in an in vitro wound closure model and how TGF-¿s influence ECM secretion and integrin expression. 5, 10, 25, 50 and 100¿m wide repeat gratings of Collagen type I, Fibronectin and Laminin patterns were stamp patterned onto glass slides and plated with MG63 cells at 50,000 cells per coverslip. Cells on the fibronectin pattern attached and elongated soon after seeding, but did not adhere readily to collagen and laminin and appeared more rounded until 18hrs after seeding. Cells aligned significantly well on the 50¿m and 100¿m wide fibronectin patterned coverslips with mean angles of alignment ~7.87¿ ¿ 3.06SD and 6.45¿ ¿ 5.08SD, respectively, compared to those with smaller width (p<0.001). In comparison, cells aligned less readily to the other two ECM proteins, showing optimal alignments of 9.66¿ ¿ 4.18SD and 14.36¿ ¿ 1.57SD to the 50¿m wide collagen and laminin patterns, respectively. Differences in cell length mirrored those of alignment, with cells acquiring the greatest length when showing the greatest degree of alignment. The results indicate that MG63 cells responded significantly better to 50 and 100¿m wide fibronectin patterns compared to those with smaller width (p<0.001) indicating that the cells may attach mostly via fibronectin specific integrins. Cell surface attachment was examined via a trypsinisation assay in which the time taken to trypsinise cells from the surface provided a means of assessing the strength of attachment. The results indicated that treatment with the solvent (HCl), TGF-¿1, 2 and 3 all decreased cell attachment, but this effect was significantly greater in the case of HCl and TGF-¿3 (p<0.001). However, there were significant differences in trypsinisation rates between HCl and TGF-¿3 (p<0.001). The wound healing response to the TGF-¿s and their solvent/carrier was also investigated in 300¿m ± 10-30¿m SD wide model wounds induced in fully confluent monolayers of MG63 bone cells. The results indicated that TGF-¿3 and HCl significantly enhance wound closure when compared against negative controls, TGF-¿1 and TGF-¿2 treatment (p<0.001). It was also found that TGF-¿1 and TGF-¿2 treatment significantly improved wound closure rate in comparison to the controls (p<0.001). Experiments were performed to determine if the HCl effects on wound closure were dose dependent. Cells were incubated with 20¿M, 40¿M, 80¿M and 160¿M concentrations of HCl prior to wounding and wound closure rates were recorded. Wound closure was dependent on HCl dose with the 80¿M and 160¿M concentrations inducing increases in wound closure rates that were both significantly greater than those induced by 20¿M, 40¿M and control treatments (p<0.001). However, there were significant differences in wound closure between the 80¿M and 160¿M treatment groups after 30hrs of treatment (p<0.001). The effect of different TGF-¿ isomers and their combinations on proliferation rate and cell length of human bone cells were also assessed. The results suggest that cell morphology changes were observed significantly more in cells treated with TGF-¿(2+3) and TGF-¿(1+3) (p<0.001). Any cell treated with TGF-¿1, TGF-¿(1+2) and TGF-¿(1+2+3) showed significantly less elongation compared to the control and other TGF-¿ isomers. In terms of proliferation rate, TGF-¿3 and TGF-¿(2+3) increased cell numbers more than TGF-¿1, TGF-¿2 and other combinations. TGF-¿1 and its combinations did not show significant proliferation and attachment compared to the control due to perhaps its inhibitory effect in contact with human bone cells. Immunostaining indicated that treatment with TGF-¿3 significantly promoted the secretion of collagen type I and anti-human fibronectin in addition to integrin (¿3 and ¿1) expression. Statistically TGF-¿3 and their combinations showed significant differences in number of cells stained for collagen type I, anti-human fibronectin, ¿3 and ¿1integrin. Any cell treated with TGF-¿1 or any combination with TGF-¿1 showed significantly lower cell number stained with the same proteins and integrins (p<0.001). Imaging with WSPR allowed observation of the focal contacts without the need for immunostaining. WSPR images revealed guided cells with high contrast band like structures at the border of cells distal to the edge of guidance cue to which they aligned and with less concentrically formed band like features across the cell body. It is believed that the high contrast features are associated with the formation of focal contacts on the edge of the cells distal to the edge of fibronectin patterns, which suggests that cell guidance is aided by a decrease in cell attachment along a guidance feature. The WSPR experiments also indicated that TGF-¿s influenced the distribution of focal contacts. In the case of TGF-¿1 treated cells the bright high contrast regions were intense but only arranged around the periphery of the cell. In TGF-¿2 and TGF-¿3 cells the bright contrast regions were weaker but again mostly localised around the periphery. These findings supported the earlier trypsinisation results

Impact of Packing and Processing Technique on Mechanical Properties of Acrylic Denture Base Materials

The fracture resistance of polymethylmethacrylate (PMMA) as the most popular denture base material is not satisfactory. Different factors can be involved in denture fracture. Among them, flexural fatigue and impact are the most common failure mechanisms of an acrylic denture base. It has been shown that there is a correlation between the static strength and fatigue life of composite resins. Therefore, the transverse strength of the denture base materials can be an important indicator of their service life. In order to improve the fracture resistance of PMMA, extensive studies have been carried out; however, only a few promising results were achieved, which are limited to some mechanical properties of PMMA at the cost of other properties. This study aimed at optimizing the packing and processing condition of heat-cured PMMA as a denture base resin in order to improve its biaxial flexural strength (BFS). The results showed that the plain type of resin with a powder/monomer ratio of 2.5:1 or less, packed conventionally and cured in a water bath for 2 h at 95 °C provides the highest BFS. Also, it was found that the performance of the dry heat processor is inconsistent with the number of flasks being loaded

Biomaterials for breast reconstruction: Promises, advances, and challenges

yesBreast reconstruction is the opportunity that provides the chance of having breast after undergoing surgical removal of the breast tissue due to cancer-related surgery. However, this varies on the stage of the cancer diagnosis and the procedure undertaken. There are many regenerative medicine methods that provide several initiatives and direct solutions to problems such as the development of “bioactive tissue,” which can regenerate adipose tissues with similar normal functions and structures. There have been several studies which have previously explored for the improvement of breast reconstruction including different variations of biomaterials, different fabrication and processing techniques, cells as well as growth factors which enable bioengineers and tissue engineers to reconstruct a suitable breast for patients with breast cancer. Many factors such as shape, proper volume, mechanical properties have been studies but very scattered with not adequate solutions for existing patients worldwide. This review article aims to cover recent advances in biomaterials, which can be used for reconstruction of breasts as well as looking at the various factors that might lead to individuals needing reconstruction and the materials that are available. The focus would be to look at the various biomaterials that are available to use for reconstruction, their properties, and their structural integrity

Development of a Basement Membrane Substitute Incorporated Into an Electrospun Scaffold for 3D Skin Tissue Engineering

yesA major challenge in the production of 3D tissue engineered skin is the recreation of the basement membrane region to promote secure attachment and yet segregation of keratinocytes from the dermal substitute impregnated with fibroblasts. We have previously shown that simple electrospun scaffolds provide fibres on which the cells attach, proliferate, and self-sort into epithelium and dermis. In a development of this in this study tri-layered scaffolds were then electrospun from poly L-lactic acid and poly hydroxybutyrate-co-hydroxyvalerate. In these a central layer of the scaffolds comprising nano-porous/nano-fibrous poly hydroxybutyrate-co-hydroxyvalerate fibres was interwoven into the bulk micro-porous poly L-lactic acid microfibers to mimic the basement membrane. Keratinocytes and fibroblasts seeded onto these scaffolds and cultured for 2 weeks showed that neither cell type was able to cross the central nano-porous barrier (shown by SEM, and fluorescence monitoring with CellTracker™) while the micro-fibrous poly L-lactic acid provided a scaffold on which keratinocytes could create an epithelium and fibroblasts could create a dermal substitute depositing collagen. Although cells did not penetrate this barrier the interaction of cells was still evident-essential for epithelial development

Effect of Transforming Growth Factor-β3 on mono and multilayer chondrocytes

Articular cartilage is an avascular and flexible connective tissue found in joints. It produces a cushioning effect at the joints and provides low friction to protect the ends of the bones from wear and tear/damage. It has poor repair capacity and any injury can result pain and loss of mobility. Transforming growth factor-beta (TGF-β), a cytokine superfamily, regulates cell function, including differentiation and proliferation. Although the function of the TGF-βs in various cell types has been investigated, their function in cartilage repair is as yet not fully understood. The effect of TGF-β3 in biological regulation of primary chondrocyte was investigated in this work. TGF-β3 provide fibroblastic morphology to chondrocytes and therefore overall reduction in cell proliferation was observed. The length of the cells supplemented with TGF-β3 were larger than the cells without TGF-β3 treatment. This was caused by the fibroblast like cells (dedifferentiated chondrocytes) which occupied larger areas compared to cells without TGF-β3 addition. The healing process of the model wound closure assay of chondrocyte multilayer was slowed down by TGF-β3, and this cytokine negatively affected the strength of chondrocyte adhesion to the cell culture surface

Effect of transforming growth factor-β on up/down regulation of integrin-β1 in primary chondrocyte culture

yesRegeneration of a damaged or non-functioning tissue requires adhesion of cells to their extracellular matrix (ECM). Thus the investigation of the level of synthesised cell adhesion molecules (CAMs) in cell culture systems play major roles in cell and tissue engineering. Adhesion of chondrocyte to a collagen type-II rich matrix, is dependent on cell adhesion molecules (CAMs) and integrins and cells adhere to ECM through integrins

Potential of electrospun nanofibers for biomedical and dental applications

YesElectrospinning is a versatile technique that has gained popularity for various biomedical applications in recent years. Electrospinning is being used for fabricating nanofibers for various biomedical and dental applications such as tooth regeneration, wound healing and prevention of dental caries. Electrospun materials have the benefits of unique properties for instance, high surface area to volume ratio, enhanced cellular interactions, protein absorption to facilitate binding sites for cell receptors. Extensive research has been conducted to explore the potential of electrospun nanofibers for repair and regeneration of various dental and oral tissues including dental pulp, dentin, periodontal tissues, oral mucosa and skeletal tissues. However, there are a few limitations of electrospinning hindering the progress of these materials to practical or clinical applications. In terms of biomaterials aspects, the better understanding of controlled fabrication, properties and functioning of electrospun materials is required to overcome the limitations. More in vivo studies are definitely required to evaluate the biocompatibility of electrospun scaffolds. Furthermore, mechanical properties of such scaffolds should be enhanced so that they resist mechanical stresses during tissue regeneration applications. The objective of this article is to review the current progress of electrospun nanofibers for biomedical and dental applications. In addition, various aspects of electrospun materials in relation to potential dental applications have been discussed

Fabrication of 3D hybrid scaffold by combination technique of electrospinning-like and freeze-drying to create mechanotransduction signals and mimic extracellular matrix function of skin

YesFabrication of extracellular matrix (ECM)-like scaffolds (in terms of structural-functional) is the main challenge in skin tissue engineering. Herein, inspired by macromolecular components of ECM, a novel hybrid scaffold suggested which includes silk/hyaluronan (SF/HA) bio-complex modified by PCP: [polyethylene glycol/chitosan/poly(ɛ-caprolactone)] copolymer containing collagen to differentiate human-adipose-derived stem cells into keratinocytes. In followed by, different weight ratios (wt%) of SF/HA (S1:100/0, S2:80/20, S3:50/50) were applied to study the role of SF/HA in the improvement of physicochemical and biological functions of scaffolds. Notably, the combination of electrospinning-like and freeze-drying methods was also utilized as a new method to create a coherent 3D-network. The results indicated this novel technique was led to ~8% improvement of the scaffold's ductility and ~17% decrease in mean pore diameter, compared to the freeze-drying method. Moreover, the increase of HA (>20wt%) increased porosity to 99%, however, higher tensile strength, modulus, and water absorption% were related to S2 (38.1, 0.32 MPa, 75.3%). More expression of keratinocytes along with growth pattern similar to skin was also observed on S2. This study showed control of HA content creates a microporous-environment with proper modulus and swelling%, although, the role of collagen/PCP as base biocomposite and fabrication technique was undeniable on the inductive signaling of cells. Such a scaffold can mimic skin properties and act as the growth factor through inducing keratinocytes differentiation