جستجوی مقالات مرتبط با کلیدواژه "ترمیم" در نشریات گروه "پزشکی"

Degenerative joint disease, especially osteoarthritis (OA), is a global disease characterized by the destruction of articular cartilage, and subchondral bone. It is estimated that about 250 million people currently suffer from cartilage defects. So far, no definite and standard treatment method for OA has been reported. Recently, cell-based therapeutic techniques have been considered one of the best therapeutic strategies for the long-term treatment of articular cartilage diseases. However, many challenges include the large scale of cells required, thus the cell-free approaches are novel tools for cartilage defect treatment. For instance, extracellular vesicles (EVs) secreted by various cells such as MSCs are in charge of the therapeutic effects of stem cells. Therefore, recently EVs have advanced as powerful cell-free transfer tools, due to their high physicochemical strength and biocompatibility.

This study is a review study that summarizes the preclinical and clinical studies that used EV-derived from different cell sources and investigates their effectiveness in treating cartilaginous tissue lesions. Current studies used small or large animal models with experimental critical size defects in knee articular cartilage to examine the effectiveness of EVs derived from MSCs. The EVs were isolated from cell sources such as adipose-derived MSCs, Bone marrow-derived MSCs, or transgenic cells. In addition, EV isolation techniques as a main challenge in studies using EVs to treat OA, specifically described in the current study. We also showed EVs isolated from each cell have unique features such as anti-inflammatory, differentiation, and therapeutic properties. We explain recent studies that use EVs as a drug carrier such as small molecules, and microRNA bioactive factors. In addition, the isolation techniques of EVs and their characterization are other challenges that we explain.

Recent studies have shown that EVs isolated from different sources inhibit the progression of OA. Also, the results of some studies indicate the ability of EVs to repair injured cartilage. Many studies showed that in critical size defects of cartilage, the use of EVs needs scaffolds. Several studies have investigated the challenges of EV release and the required EV dose based on the size of the lesion. EVs are rapidly emerging as novel therapeutic approaches for treating cartilage lesions and OA. Despite many advances in cell therapy and promising results reported in numerous disease models, the use of cells especially genetically modified cells has limitations in regenerative medicine. It is worth noting that the use of EVs derived from stem cells or transgenic cells has no harm to the human body. As a result, therapeutic EVs have been introduced as a new therapeutic approach that does not have the same potential risks as cells.

Despite the positive results of EV in the treatment of cartilaginous lesions, it appears that the EV therapeutic barrier requires further testing in larger animal models before clinical trials. For instance, the regeneration of critical-size lesions requires the use of EVs incorporated by suitable scaffolds under dynamic conditions. Therefore, the fundamental questions to be considered are: How to use EVs as a nanoparticle instead of stem cells in combination with tissue engineering methods? What are the biological properties of EVs? What doses of EVs have the mechanistic potential for the treatment of different sizes of cartilage lesions and how EVs are stable in lesions? What is the role of EVs in the homeostasis and pathogenesis of junctions?

Indirect Pulp Cap (IPC) is a treatment that preserves pulp vitality. This study aimed to investigate the success rate of indirect pulp cap therapy as a conservative treatment for deep carious lesions in permanent teeth.

In this cross-sectional study, among the patients for whom IPC treatment was performed in 2015, 100 patients were randomly selected. Vital pulp tests (thermal, cold and electrical test) and pre-apical tests (percussion, tactility and chewing) were performed for the target tooth and control teeth. The tooth was examined radiographically and the signs of success or failure of treatment were examined, also.

Of the 100 patients who received IPC, 91 had signs of a successful treatment after 4 years, and only 9 had failed. In other words, the success rate of the treatment was 91% and the failure rate of treatment was 9%.

According to the results of this study, IPC is an appropriate treatment for teeth with deep caries in both sexes and all ages, the type of the material used to seal the pulp and the restorative material used for dental restoration does not affect the success rate. But the most important factors are to apply the indirect pulp treatment carefully, avoiding bacterial contamination, and to seal the teeth with a hermetic restoration.

Selenium is a trace element and its nanoparticle has antimicrobial activity and due to their low toxicity and excellent biological performance, it has many biological applications in tissue engineering. The aim of this study was to investigate the effect of selenium nanoparticles on stem cell interaction on rat decellularized sciatic nerve scaffolds.

In this laboratory study, the effect of selenium nanoparticles on stem cell interaction on rat decellularized sciatic nerve scaffold, scaffolds were prepared using Sondell decellularizaton method and stored in PBS solution containing antibiotics. Biomechanical and histological evaluations of scaffolds were examined using the light microscope. In the next step, adipose stem cells were seeded on the scaffold and the viability of the cells on the scaffold in the presence of selenium nanoparticles were measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Data were analyzed by one-way analysis of variance and Tukey's post hoc test.

The tensile test showed that after decellularization, extracellular matrix components such as collagen, laminin, and elastin were retained in the scaffold. Also, DNA content was significantly reduced in the scaffold group (p<0.01). The results of MTT test showed that selenium nanoparticles had no toxicity on stem cells cultured on the scaffold.

The biocompatibility of scaffolds and the viability of stem cells treated with selenium nanoparticles were not significantly different from the control group. Therefore, it can be evaluated as a reinforcing factor to increase the efficiency of scaffolds for the use in regeneration of the nerve lesions.

Wound healing is a complicated process involving the proliferation of the epithelial cells, deposition of granulation tissue as well as recruitment of inflammatory cells. It also is a hot topic of research for trauma, orthopedics and general surgery studies. There are many forms of cells involved in this process. This study aimed to design a tissue-engineered wound dressing consisting of chitosan fibers containing silver ion bioactive nanoparticles for wound healing.

The present study is an experimental study that was conducted in the research laboratory of the Department of Biology of Mohaghegh Ardabili University from April to November 2019. All experiments of this study have been performed under the ethical guideline of Helsinki and in accordance with the Ethics Committee of the Mohaghegh Ardabili University of Ardabil (Iran). The wound dressing of nanofibers was prepared by the sol-gel method. Cytotoxicity was assessed by MTT assay. Then the antimicrobial properties of nanofibers were determined by the disk diffusion method. SEM and AFM images were obtained from nanofibers. Finally, nanofibers were analyzed by the FTRI method.

Results of the prepared tissue-engineered wound dressing consisting of chitosan fibers containing silver ion-doped bioactive nanoparticles showed that cytotoxicity was at an appropriate level. The nanofibers prepared with 2% silver nanoparticles produced a 10 mm inhibition zone against Staphylococcus aureus and a 9 mm inhibition zone against Escherichia coli. Therefore, the best percentage of scaffolds in the present study was 2%. Also, results of the SEM micrographs and AFM image analysis of the scaffolds showed that the nanofibers had good roughness and a proper structure for cell seeding and attachments. Besides that, FTIR analysis also showed that the prepared nanofibers had standard bonds.

Chitosan-Silver nanoparticles scaffold have antimicrobial activity on Gram-negative and positive bacteria. The results of the toxicity test also showed that it did not have much toxicity on the cultured cells. Therefore, it can be considered for therapeutic applications, such as wound dressing.

Mesenchymal stem cells (MSCs) have been identified as an attractive source for cell therapy of damaged tissues. The multipotential differentiation capability, easy accessibility, low immunogenicity and significant role in wound healing physiology have led to the widespread use of these cells for wound healing. In this review study, the role of mesenchymal stem cells in repair of skin wounds is discussed .

This review was written based on findings from a search of the PubMed and Google Scholar databases between 1990 and 2020.

Mesenchymal stem cells have important roles at all stages of wound healing. These cells migrate to the site of skin damage and not only differentiate into the skin cells but also through paracrine signalling inhibit the immune and inflammatory responses, induce proliferation and differentiation of resident progenitor cells and result in angiogenesis, epithelialization and granule tissue formation. In the regeneration and maturation phase, the MSCs reduce scar formation and wound contraction and increase collagen expression and wound tensile strength. These cells alter their function based on the biomolecular properties of the lesion site, and create a wound-healing rather than fibrotic microenvironment .

Todays, significant advances have been made in the delivery of MSCs into healing wounds. These cells are delivered via intravenous or intradermal injection, or delivered with scaffolds, as a fibrin polymer spray or with hydrogels. In addition, the extracellular vesicles and conditioned medium of MSCs alone are effective. Future studies could lead to more effective strategies for the use of mesenchymal stem cells in wound healing . Received

Caries is one of the most common infectious diseases in childhood, the treatment of which in children varies according to the extent of the lesion and the childchr('39')s behavior. Among the various treatments, the use of prefabricated metal crowns or (SSC) is extending rapidly. Therefore, in the present study, we examined the applications of these crowns and their advantages and disadvantages. The data used in this review was extracted from articles searched in web pages such as Scopus, PubMed and google scholar. After reviewing the abstracts, the full text of the articles related to the topic was reviewed. Due to the high prevalence of caries in deciduous teeth and the prevention of complications due to premature loss of deciduous teeth, nowadays the use of stainless steel crowns that have high durability and longevity is very widespread. Most clinical articles have recommended the use of these crowns due to their efficiency and cost-effectiveness.

Today, resin composites are one of the most commonly used materials in restorative dentistry. However, failure in resin treatments is also common due to its chemical nature and its high talent for decay recurrence. According to conservative approaches, "conservative" treatments are more likely to be considered than "Replacement" of damaged remedies. The purpose of this study was to compare different surface preparation methods on composite surfaces to achieve the highest bond strength between the old and new composites after accelerated aging. First, composite cylinders with a diameter of 6 and a height of 5 mm were prepared using an incremental technique and a microhybrid resin composite. The specimens were stored in distilled water for 6 months at 37°C and then the surfaces of all aged compsites were roughened using diamond milling followed by phosphoric acid etching. The specimens were randomly subjected into five groups. Group 1: GC Composite Primer. Group 2: Universal bonding containing silane (Kuraray). Group 3: Self etching adhesive (SE bond; Kuraray) Group 4: silane (Ivoclar Vivadent) + Second bottle of SE bond bonding system (Kuraray). Group 5: control group with no treatment. Then, 5 mm incremental of new composite (similar to the aged composite with different color) were placed on the surfaces of specimens, sectioned, and thermocycled for 3000 cycles for the microtensile bond strength evaluation. The specimens were evaluated using a stereomicroscope after failure. Data were analyzed by one-way ANOVA and Post Hoc Tukey test. The specimens in which silane and SE bond were used showed the highest mean microtensile bond strength and those treated by universal bond showed the least bond strength which were significantly different (P=0.02). All samples had cohesive failure patterns in all groups and the percentage of failures in old and new composites did not differ significantly (P=0.69). : Based on the results, all surface preparations used in this study could provide an appropriate bond strength for repair of old composite restorations. Also, the microtensile bond strength between the old and new composites was higher than the cohesive strength of resin composite itself. However, the mean microtensile bond strength value for the group treated by universal bond was significantly lower than those treated by silane and hydrophobic containing bonding system.

Tissue engineering is a developing multidisciplinary and interdisciplinary field involving the use of bioartificial implants for tissue remodeling with the target for repair and enhancing tissue or organ function. Acellular nerve has been used in experimental models as a peripheral nerve substitute. The purpose of the present study was to evaluate the mechanical and histological characteristics of acellular nerve scaffolds compared to the fresh nerve for application in environmental nerve repair.
This experimental study was conducted in Ferdowsi University of Mashhad Regeneration Research Laboratory, Mashhad, Iran, from May 2017 to October 2018. In this study for preparing the scaffold. The rats were sacrificed by intraperitoneal anesthesia with 10 % Chloral Hydrate solution. Then sciatic nerve fragments of the rats were removed above the nerve branching site and after cleansing of the tissues were decellularized by Sondell method, briefly nerves were treated with a series of detergent baths consisting of distilled water for 8 h, Triton X-100 for 12 h, and sodium deoxycholate for 24 hours according to the Sondell protocol. All acellularization steps were performed at room temperature. Then decellularized scaffolds were evaluated histologically and mechanically.
The results of tissue evaluations showed that decellularization of scaffolds were done completely, this was demonstrated by hematoxylin and eosin staining and DAPI staining. Also the specialized tissue evaluations by picro-fuchsin staining and evaluation the scaffolds by scanning electron microscopy (SEM) micrographs showed that the collagen and elastin strands are relatively preserved in the extracellular matrix in comparison with control groups. As well as mechanical examination of scaffolds in tensile test showed that extracellular matrix of scaffolds was relatively preserved the main components of tissue compared to control group and scaffolds have good mechanical resistance quality for use in tissue engineering.
The results of the present study showed that decellularized scaffolds that prepared with Sondell decellularization method by preserving the main components of the tissue can be a good platform for investigating cellular behaviors.

 During cavity preparation, smear layer is created that this layer should be removed with irrigators. Leakage may be decrease after irrigation. The aim of this study was to evaluate the leakage after irrigation by chlorhexidine 2%, sodium hypochlorite 2.5% and water in glass ionomer class V restorations.  In this experimental-in vitro study, the class V restoration preparation was prepared in the standard cervical portion of buccal accept in 51 human premolar teeth. The samples were divided to 3 groups due to type of irrigants. Group 1: sodium hypochlorite 2.5% was applied in cavity for 30 seconds. Group2: chlorhexidine 2% was applied in cavity for 30 seconds. Then, all cavities were washed for 10 seconds in order to remove agents and their extra waters. Group3: only washed with water. The cavities were filled by Glass ionomer reinforced composite resins. After 1000 thermal cycles of 5-55 °c, the microleakage of samples, was evaluated with dye penetration and data was analyzed statistically with chi-square.  The microleakage of enamel were 94.1% in water irrigant, 41.2% in chlorhexidine 2%, 17.6% in sodium hypochlorite 2.5% (p<0.001) and for dentin, in water, chlorhexidine 2% and sodium hypochlorite 2.5% were 88.2%, 70.6% and 17.6% respectively. (p<0.001)

Peripheral nervous system has an innate regenerative ability, and in severe injuries leading to nerve destruction, repair does not occur spontaneously and medical intervention is required. In this regard, dexamethasone is one of useful drugs prescribed for neurological recovery after spinal cord injury. The objective of the present study was to assess the effect of dexamethasone on functional recovery and histological changes following sciatic nerve transect and regeneration with the acellular scaffolds in male Wistar rats. Fifty male Wistar rats were randomly divided into five groups of 10. The groups included: negative control group(left sciatic nerve was transecte), sham-operated group) surgical procedure without the nerve transect ), and experimental groups 1 and 2 (sciatic nerve was transected and regenerated with acellular nerve scaffold) treated with 1 and 2 mg/kg of dexamethasone, respectively. Experimental group 3 (sciatic nerve was transected and regenerated with acellular nerve scaffold) was injected with vehicle. Then, 1 cm of left sciatic nerve was exposed and replaced with a piece of scaffold. Behavioral, electrophysiological, and morphological alterations were evaluated during the experiment. Findings: with dexamethasone in comparison with the control group (P < 0.05). Analysis of gastrocnemius muscle mass in groups treated with dexamethasone in comparison with negative control group showed that muscle atrophy was reduced; also the dexamethasone-treated group presented significantly greater nerve fiber, axon diameter, and myelin sheath thickness (P < 0.05). Discussion & Conclusions: The results showed that the administration of dexamethasone after sciatic nerve transects and grafting the acellular scaffold increased motor function in a rat animal model.

This study was performed to investigate the distribution of stress in indirect resin restorations of class II MOD cavities for obtaining the optimum wall angle and also the effect of axiopulpal angle bevel using 3D finite element analysis (FEA).
Material & A three-dimensional model of normal mandibular first molar and three class II cavity models with different wall angles were created. Also, all models were examined with axiopulpal angle bevel. The vertical occlusal force of 100 N was applied. The characteristics of all materials were defined as isotropic and elastic and, with the aid of a linear analysis; the distribution of stress and the maximum stress created in each model were obtained in mega-Pascal scale. T test was used for statistical of data.
The maximum stress in the simulated normal tooth was 24.63 MPa. Distribution of stress indicates the accumulation of pressure in the center and the furcal region of the first molar, as well as the cusps in the occlusal region. In beveled model of 95-degree angle, maximum stress was 24.90 MPa with a decrease of 0.05 maximum stress compared to the non-beveled model. In the cutting angle of 97.5, the maximum stress was 24.85 in the no-bevel model to the maximum stress of 24.80 in the model compared with axiopulpal angle bevel, which showed achieved a decrease of 0.05 in the maximum stress. At the cutting angle of 100, the maximum stress of 25.30 was in the no-beveled model comparing to maximum stress of 25.20 in the model with axiopulpal angle bevel, which showed red action of MPA.
Considering the limitations of such software studies, it seems that according to the results, the best treatment result is at angle of 97.5. Axiopulpal angle bevel reduces the maximum stress in the restoration and reduces the chance of failure

Introduction & Burns are usually considered as the most violent trauma. Wound healing is a complex process that is usually associated with various growth and biological factors. During the process of wound healing, the dressing used for restoration and repairing tissues of the dermis and epidermis of wound. Medicinal plants provide initial treatment compared to synthetic materials are inexpensive, safe and natural can be a source of useful and effective in the treatment of burns. The aim of this study was to evaluate the effects of Adib Derm on the healing of full- thickness second degree burn wound in Rat.
In this experimental study which was performed in the animal lab of the Hazrat Fatemeh Hospital in Tehran, 24 adult male rats with an approximate weight of 250- 300 grams, with deep burns of 2 cm 4×2 dimensions were prepared and divided into 2 groups of 12. We used Adib derm (Adib exir pharmaceutical company - Iranian scholar) in first group and Vaseline gas in the second group (control) to dressing every day until healing is complete and the wound healing process by shooting as every 7 days with Image J, ver. 1.45, (NIH, Maryland, USA) was monitored. On 14 and 28 to determine the amount of collagen and inflammatory cells were sent for pathological sample from burn wounds.
The results showed that during days 7 to 21 in each group reduced wound size (P According to the results of the present study, the effect of this ointment on the recovery of burn wounds was not as much as we expected. Thus, it is suggested that further studies perform with a larger sample size and with the change in the method of dressing and superficial burns.

The positive effect of mesenchymal stem cells in healing of various types of tissue damage such as burn has been reported. The therapeutic potential effects of mesenchymal stem cells influenced by certain agonists from their surface called Toll like receptor (TLR) can be modified into proinflammatory and anti-inflamation phenotypes. It is believed that modification of phenotypes of mesenchymal stem cells can affect their therapeutic function. Therefore, the aim of this study was to assess the influence of Poly(I:C) (TLR3 agonist) versus LPS (TLR4 agonist) in stimulating mesenchymal stem cells and alteration of the therapeutic potential of these cells for the treatment of third-degree skin burns in mice which was performed at institute of Bio-technology, Urmia University, Urmia, Iran.
Total 36 male mice aged 7-8 weeks with 25-30 gr average weights were selected. Based on burn standard method, a stainless-metal rod was heated to 100 in boiling water and burn wounds of 9 second duration were created on each mouse. Within an hour of burn induction, the mice were randomly assigned to four groups, control group with daily application of silver sulfadiazine gel, treatment 1 was treated by receiving subcutaneously 106 unstimulated mesenchymal cells, treatment 2 was treated by receiving subcutaneously 106 lipopolysaccharide (LPS)-stimulated mesenchymal cells, treatment3 was treated by receiving subcutaneously 106 Poly (I:C)-stimulated mesenchymal cells. Biopsies were taken from wounds and some normal tissues around it on days 7, 14 and 21 after burn induction. All samples were examined histopathologically by Hematoxilin-Eosin and masson trichrome stains in terms of thickness of the granulation tissue, tissue repair process, array of granulation tissue and deposition of collagen fibers in the repairing area. Checking normality test was processed using SPSS 18.0 Software (SPSS Inc, Chicago, IL, USA) and data then were analyzed using one-way ANOVA, Tukey and post hoc test.
Thickness of the granulation tissue on day 7 differed significantly between the control group and treatment 1 (P Increased therapeutic potential of LPS -stimulated mesenchymal stem cells versus reduced therapeutic potential of Poly (I:C)-stimulated mesenchymal stem cells can be as a result of attaining the proinflammatory versus anti-inflammatory phenotype in mesenchymal stem cells in response to the respective agonists, respectively.

Aims: Following the peripheral nervous system trauma, prescribing anti-inflammatory agents is one of the strategies to control the damage and promoting the recovery process. The aim of this study was to investigate the effects of methylprednisolone on improvement of motor function and tissue changes following sciatic nerve transection and repairing by decellularized scaffolds transplantation in rats.
In this experimental study, 50 adult male Wistar rats were randomly divided into 5 groups of 10; negative control group (receiving no medication with transection of the sciatic nerve), sham group (nerve-mediated surgery with solvent drug), experimental groups 1 and 2 (transection of the sciatic nerve and scaffold transplantation with 1- and 30mg/kg of methylprednisolone intraperitoneally) and experimental group 3 (transection of the sciatic nerve and scaffold transplantation with solvent drug). Behavioral, electrophysiological and tissue tests were performed during the experiment. Data were analyzed by SPSS 16 software and using one-way ANOVA and Tukey's post hoc tests.
Findings: the rate of repair and improvement of motor function was increased significantly in the treated groups with methylprednisolone compared to the control group (p The prescription of methylprednisolone increases the amount of motor improvement and tissue repair after the sciatic nerve transection and the decellularized scaffold transplantation. Recovery of the motor and tissue functions at high dose of methylprednisolone is better than low dose.

The success of root canal treated teeth with periapical lesions was addressed in several studies. However, in some cases, such as traumatic occlusion, these lesions may remain stable. On the other hand, the effect of traumatic occlusion in development of pulp and periapical diseases is not known thoroughly.
Case Report: The article reports the remaining of periapical lesion after appropriate endodontic treatment and surgery in a 17-year-old patient. However, the patient symptoms improved after removal of premature contacts and periapical lesion healed.
Elimination of premature contacts during treatment can be one of the influential factors in treatment outcomes.