Articular cartilage injury poses a major challenge for both the patient and orthopaedician. Articular cartilage defects once formed do not regenerate spontaneously, rather replaced by fibrocartilage ...which is weaker in mechanical competence than the normal hyaline cartilage. Mesenchymal stem cells (MSCs) along with different growth factors and scaffolds are currently incorporated in tissue engineering to overcome the deficiencies associated with currently available surgical methods and to facilitate cartilage healing. MSCs, being readily available with a potential to differentiate into chondrocytes which are enhanced by the application of different growth factors, are considered for effective repair of articular cartilage after injury. However, therapeutic application of MSCs and growth factors for cartilage repair remains in its infancy, with no comparative clinical study to that of the other surgical techniques. The present review covers the role of MSCs, growth factors and scaffolds for the repair of articular cartilage injury.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The stem cells, owing to their special characteristics like self‐renewal, multiplication, homing, immunomodulation, anti‐inflammatory, and dedifferentiation are considered to carry an ...“all‐in‐one‐solution” for diverse clinical problems. However, the limited understanding of cellular physiology currently limits their definitive therapeutic use. Among various stem cell types, currently mesenchymal stem cells are extensively studied for dog clinical applications owing to their readily available sources, easy harvesting, and ability to differentiate both into mesodermal, as well as extramesodermal tissues. The isolated, culture expanded, and characterized cells have been applied both at preclinical as well as clinical settings in dogs with variable but mostly positive results. The results, though positive, are currently inconclusive and demands further intensive research on the properties and their dependence on the applications. Further, numerous clinical conditions of dog resemble to that of human counterparts and thus, if proved rewarding in the former may act as basis of therapy for the latter. The current review throws some light on dog mesenchymal stem cell properties and their potential therapeutic applications.
•Properties and sources of MSCs and their relevance to clinical application.•Isolation, culture and characterization of the cells.•Current limitations of the isolation protocols and variabilities in ...characterization markers.•Potential applications of the cells in clinical ailments and what is the current status.•What are the challenges ahead to meet the desired results?
The stem cells make the backbone of repair system in an individual, which is attributed to their special characteristic features like self-renewal, multiplication, homing, immuno-modulation and plasticity. Due to the limited control over the cellular processes, variability in results and small number of controlled clinical trials stem cell applications currently remain limited, however their potential and applicability in biological research and therapy cannot be overemphasized. Among various stem cell types, mesenchymal stem cells (MSCs) are extensively studied for clinical applications owing to their readily available sources, easy harvesting and culturing, and their ability to differentiate into numerous tissue cells, besides, minimal teratogenic potential. Sheep is one of the commonly used large animal models for humans. Sheep MSCs have been isolated, culture expanded and characterized similar to that of humans and utilized in various translational models for human medical applications. The current review throws light on sheep mesenchymal stem cell sources, characterization and potential therapeutic applications in perspective of human medicine. The information summarized in the manuscript has been taken mainly from authentic sources.
Summary
The study was undertaken to evaluate the feasibility of a simple, inexpensive model of circular external fixator (CEF) for use in large ruminants. A simple model of CEF frames consisting of ...four full rings (13–19 cm diameter, 4 cm wide and 4 mm thick with 18–24 holes) connected by threaded rods (8 mm diameter, 10–15 cm long) and nuts was developed using mild (low carbon) steel and were nickel‐plated. In the first phase of the study, three male cow calves were utilized to study the feasibility of application of the fixators in the metatarsus, tibia and radius, in reference of adaptation and tolerance by animals. In the second phase, the fixators were tested in osteotomized bones. Six bull calves of 1.5–2 years of age weighing about 200–250 kg were utilized for this purpose. After preparing the area for aseptic surgery, under xylazine (at 0.1 mg/kg, i.m.)‐ketamine (i.v. till effect) general anaesthesia, the test bone (metatarsus, radius and tibia in two animals each) was approached through the medial surface and an osteotomy was created with a saw and chisel at the mid‐diaphysis. The pre‐constructed 4‐ring CEF was mounted on the limb around the test bone in such a way that it formed a cylinder with the axis of the limb at the centre. Each ring was then fixed to the bone with a pair of beaded wires (316 SS) of 3.5 mm diameter. During the post‐operative period, the animals were observed for any change in behaviour, tolerance of the fixators, the weight bearing on the test limb, the status of the fixator, and the level of reduction of the osteotomy, alignment and healing at different intervals.
The fixation of CEF was easier in the metatarsus and radius than in the tibia. The inner ring diameters found adequate for metatarsus, radius and tibia were 13–15 cm, 15–17 cm and 17–19 cm, respectively. The fixators applied to different bones were well‐tolerated, and the animals could lay down, stand and walk freely with the fixator without any problems. All the animals showed good weight bearing in the immediate post‐operative period. Weight bearing, however, slightly reduced in the inflammatory period and showed improvement after about 4 weeks. Wire tract infection was seen in all the animals, which was more on proximal wire tracts on lateral aspect of limbs. Circular fixators were well‐tolerated by all the animals, and there was no breaking/bending of connecting rods, slotted bolts or the rings at any stage of observation. Slight bowing of some wires was noticed in cases of tibia and radius (in phase II) and bending of some wires was noticed from first week in two animals one each in radius and tibia. Bone fragments were well maintained until healing occurred (appearance of bridging periosteal callus) at 60–70 days. The functional results were good in all but one case of tibia, where a mal‐union was recorded. From this study, it can be concluded that CEF are well‐tolerated by large ruminants and can be used to treat long bone fractures. The fixator assembly using mild steel is sufficiently strong to maintain fracture fixation and is inexpensive. The simple design of the CEF appears to be sufficient to treat simple diaphyseal fractures of the metatarsus and radius. Improvement in the technique of fixation and design‐like coupling of linear and circular fixator components into hybrid constructs may help to provide greater rigidity in treating tibial and open long bone fractures.
Stem cell, a wonder cell, acts as a basic unit for an individual development in early prenatal life, andrepairs and regenerates the tissue and/ organ in post-natal life. The stem cell research ...although conducted extensively is still in its infancy for standardized therapeutics. Among various stem cells types, multi-potential mesenchymal stem cell (MSC) is mainly evaluated for therapeutic applications. These cells have been isolated from almost all the body organs/ tissues and fetal membranes and are culture expanded for higher concentrations. Like human, MSCs harvested from veterinary species are characterized on the basis of International Society for Cellular Therapy (ISCT). Extensive literature on their therapeutic applications in musculoskeletal and non-musculoskeletal systems evidences their potential utility under clinical settings. Currently, limited understanding in their hysiological mechanisms and availability of limited non-uniform in vivo studies restrict their definitive therapeutic applications. Lack of regulatory set up in India makes MSCs research in veterinary medicine a more complicated field. This review details the current status and possible ways to improve MSCs therapeutic applications in veterinary medicine, in general and in Indian system, in particular.
Information security and privacy are crucial in a modern-day communication system. Extensively used cryptography based security in communication prevent unauthorized decoding, but it does not ensure ...the concealment of information. However, covert communication provides secure transmission of secret information over the unsecured channel. This paper proposes the covert communication integrate into wavelet packet transform Orthogonal Frequency Division Multiplexing (OFDM) system. Bit Error Rate and Quality assessment of covert communication in conventional OFDM and proposed covert communication are evaluated. Also, the comparative performance evaluation of proposed covert communication under divergent digital modulation levels is presented. Experimental results reveal a significant improvement in BER for a given SNR with the proposed covert communication system.
Purpose The purpose of this study was to evaluate and compare the biomechanical properties of a unicortical button with an interference screw used for subpectoral biceps tenodesis. We also describe ...the anatomic dangers of bicortical button use in the subpectoral location. Methods Twenty-eight fresh-frozen human cadaveric shoulders with a mean age of 52 years were studied. The specimens were randomly divided into 4 experimental biceps tenodesis groups (n = 7): unicortical button, interference screw, bicortical suspensory button, and bicortical suspensory with interference screw (Arthrex, Naples, FL). Each tenodesis specimen was mounted on a mechanical testing machine, preloaded for 2 minutes at 5 N, cycled from 5 to 70 N for 500 cycles (1 Hz), and loaded to failure (1 mm/s). We determined the mode of failure and computed the ultimate load to failure, yield load, pullout stiffness, and displacement at peak load. Calculations of the distance between the axillary and radial nerves with respect to the bicortical buttons were also calculated in 6 specimens. Results There was no statistically significant difference ( P > .05) among groups in terms of age, ultimate load to failure, pullout stiffness, or displacement at peak load. Suture-tendon interface failure was the most commonly observed mode of failure. The axillary nerve was on average 7.8 mm from the bicortical button; however, in 6 specimens the nerve was less than 3 mm away. Conclusions The use of a unicortical button for subpectoral biceps tenodesis provides biomechanical properties similar to the use of an interference screw. In addition, the use of a bicortical button in this area of the proximal humerus puts the axillary nerve at risk. Clinical Relevance Using a unicortical button subpectoral biceps method may provide a surgeon with a safe and technically easy and reproducible technique while providing similar biomechanical properties to a known standard implant.
FSO or free space optics is a familiar name used in a wide array of applications in the area of telecommunications. Due to its features of low maintenance cost and deployment time, most of the ...applications consider FSO as the alternative solution for appropriately replacing fiber optics. In this work, we have designed 100 Gbps FSO system by combining mode division multiplexing (MDM) and optical code multiple access scheme (OCDMA). Ten channels, each carrying 10 Gbps data, are transported over 8 km FSO link by using MDM of two Laguerre Gaussian modes and random diagonal codes. Moreover, the performance of proposed MDM–OCDMA–FSO system is also investigated under atmospheric turbulences.
The present study evaluated healing potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) and BM-MSCs-conditioned medium (BM-MSCs-CM) for acute and subacute injuries in the rabbit ...peripheral nerve injury model. The regenerative capacity of MSCs was evaluated in 40 rabbits divided into eight groups, four groups each for acute and subacute injury models. BM-MSCs and BM-MSCS-CM were prepared by isolating allogenic bone marrow from the iliac crest. After inducing sciatic nerve crush injury, different treatments consisting of PBS, Laminin, BM-MSCs + laminin, and BM-MSCS-CM + laminin were used on the day of injury in the acute injury model and after ten days of crush injury in the subacute groups. The parameters studied included: pain, total neurological score, gastrocnemius muscle weight and volume ratio, histopathology of the sciatic nerve and gastrocnemius muscle, and scanning electron microscopy (SEM). Findings indicate that BM-MSCs and BM-MSCS-CM have augmented the regenerative capacity in acute and subacute injury groups with a slightly better improvement in the subacute groups than the animals in acute injury groups. Histopathology data revealed different levels of regenerative process undergoing in the nerve. Neurological observations, gastrocnemius muscle evaluation, muscle histopathology, and the SEM results depicted better healing in animals treated with BM-MSCs and BM-MSCS-CM. With this data, it could be concluded that BM-MSCs support the healing of injured peripheral nerves, and the BM-MSCS-CM does accelerate the healing of acute and subacute peripheral nerve injuries in rabbits. However, stem cell therapy may be indicated during the subacute phase for better results.
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•Local application of BM-MSCs in laminin gel enhances healing of acute and subacute peripheral nerve injuries in rabbits.•Stem cell conditioned medium supports the healing of acute and subacute peripheral nerve injuries in rabbits.•Therapeutic potential of stem cell conditioned medium is comparable to the BM-MSCs.•The subacute injuries respond better to the stem cell treatment than the acute injuries of peripheral nerves in rabbits.
The evolution in communication techniques has created wide threats for crucial information transfer through a communication channel. Covert communication with steganography is a skill of concealing ...secret information within cover object and hence shields the data theft over rapidly growing network. Recently, diverse steganography techniques using edge identification have been proposed in literature. Numerous methods however utilize certain pixels in the cover image for inserting edge information, resulting in significant deformation. The conventional edge detection method limits the deployment of edge detection in steganography as concealing the information would introduce some variations to the cover image. Hence inserting data in pixel areas recognized by existing conventional edge detection techniques like canny cannot ensure the recognition of the exact edge locations for the cover and stego images. In this paper, an Adaptive steganography method based on novel fuzzy edge identification is proposed. The method proposed is proficient of estimating the precise edge areas of a cover image and also ensures the exact edge location after embedding the secret message. Experimental results reveal that the technique has attained good imperceptibility compared to the Hayat Al-Dmour and Ahmed Al-Ani Edge XOR method in spatial domain.
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