جستجوی مقالات مرتبط با کلیدواژه "poly (a:u)" در نشریات گروه "پزشکی"

Peripheral nerve injury (PNI) is a critical clinical issue primarily caused by trauma. Tissue engineering approaches using nanofiber scaffolds have been extensively explored to improve material quality and create an environment resembling the natural extracellular matrix (ECM). 

In this study, we employed electrospinning technique to fabricate a composite scaffold comprising poly(ɛ-caprolactone) (PCL) and collagen (Col) loaded with all-trans retinoic acid (RA), a neural patterning and signaling chemical known to promote nerve regeneration. 

The synthesized nanofiber scaffold exhibited a diameter of 391±79 nm and a tensile strength of 250±13 MPa, providing sufficient support for native peripheral nerve regeneration. The inclusion of Col enhanced the scaffold’s hydrophilic behavior (contact angle: 43±6°), ensuring stability in an aqueous solution. Moreover, the results demonstrated the proliferation and adhesion of nerve cells on the scaffold, aligning with the directions of the warp and weft of the nanofiber mat. Importantly, the scaffolds demonstrated non-toxicity, making them a promising substitute for the native ECM for enhanced cell attachment and proliferation. Finally, immune-histochemistry analyses further confirmed that the scaffolds supported the release and growth of neurites, promoting cell differentiation toward nerve repair. 

The RA-loaded scaffolds demonstrated the enhanced biocompatibility, supported neurite growth, and showed potential as a capable candidate for nerve regeneration.

Nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroid analgesics are recommended to alleviate or reduce pain. Regrettably, many of these drugs may induce bleeding, dyspepsia, cardiac complications, renal issues, and various short- or longterm adverse effects. Consequently, there has been an escalation in the endeavor to develop natural anti-inflammatory medications, driven by the growing number of individuals seeking natural therapies to manage their pain. The polyherbal formulations (Yoyo and Dr. Iguedo Goko bitters) have not assessed their antioxidant and anti-inflammatory activities; hence, this study “in vitro antioxidant and anti-inflammatory activities of selected polyherbal formulations sold in Nigeria.”

The evaluation of antioxidant activity was performed using three assays: 2,2-diphenyl- 1-picrylhydrazyl (DPPH) radicals, hydrogen peroxide (H2O2) scavenging activity, and ferric reducing antioxidant power. In vitro, anti-inflammatory efficacy was investigated using the human red blood cell (HRBC) membrane stabilization technique.

The DPPH radical scavenging ability result was observed; the IC50 value of Yoyo bitters (40.63 ± 0.90 % at 250 μg/mL) was highest, while Dr. Goko bitters (3.26 ± 0.21% at 50 μg/mL) was lowest. Meanwhile, the positive control (ascorbic acid) had an IC50 value of 93.54 ± 0.57% at 250 μg/mL. The ferric-reducing antioxidant power of the samples was highest in Dr. Goko bitters, 1.96 ± 0.02 % at 250 μg/mL, and lowest in Dr. Goko and Yoyo bitters, 0.46 ± 0.01% at 100 and 50 μg/mL, respectively. The hydrogen peroxide free radical scavenging activity of the samples was highest in Yoyo bitters, 58.0.3 ± 0.60 % at 250 μg/mL, and lowest in Dr. Goko bitters, 7.28 ± 0.02 % at 50 μg/mL. The anti-inflammatory findings indicate that Yoyo bitters exhibited the highest percentage protection (89.46 ± 6.11%) at a concentration of 1000 μg/ mL, while the lowest percentage protection (26.62 ± 1.13%) was observed at a concentration of 200 μg/mL. The reference standard diclofenac sodium has a percentage of 90.46 ± 1.44 at a concentration of 1000 μg/mL. Meanwhile, the poly-herbal formulations had the highest and lowest total phenolic concentrations in Yoyo bitters (97.52 ± 1.43 mg GAE/g at 250 μg/mL), and Dr. Goko bitters (47.3 ± 1.44 mg GAE/g at 50 μg/mL), respectively.

The findings suggest that the formulations might not have effective antioxidant and anti-inflammatory activities when compared with the reference standard drugs (ascorbic acid and diclofenac sodium), respectively.

 Hemorrhage control and anti-infection play a crucial role in promoting wound healing in trauma-related injuries.

 This study aimed to prepare nanoparticles with dual functions of hemostasis and antibacterial properties.

 The dual-functional nanoparticles (CDCA-PLL NPs) were developed using a self-assembly method based on the electrostatic forces between Poly-L-lysine (PLL) and Chenodeoxycholic acid (CDCA). The physicochemical properties, hemostatic properties, and antibacterial activities were investigated.

 The prepared nanoparticles displayed a spherical structure, exhibiting a high drug loading capacity, encapsulation efficiency, and good stability. The CDCA-PLL NPs could reduce the hemolysis caused by PLL and promote the proliferation of human fibroblasts, indicating excellent biosafety. Moreover, CDCA-PLL NPs demonstrated a shorter in vivo hemostasis time and reduced blood loss in mouse tail vein hemorrhage, femoral vein hemorrhage, femoral artery hemorrhage, and liver hemorrhage models. Also, CDCA-PLL NPs showed excellent antibacterial efficacy against E. coli and S. aureus.

 CDCA-PLL NPs have great potential to be extensively applied as a hemostatic and antibacterial agent in various clinical conditions.

The objective of this research was to explore how the addition of boron nitride (BN) nanoparticles in the concentrations of 1% and 1.5% w/w affect the impact strength and surface roughness of heat-cured poly methyl methacrylate resin (PMMA).

Sixty specimens were made from heat-cured acrylic resin and then divided into control, 1%, and 1.5% w/w BN groups. The impact strength and surface roughness were investigated. One-way ANOVA and Tukey’s post hoc test were used for data analysis.

Statistically significant difference is found among the three study groups regarding impact strength (P=0.011) and surface roughness test (P < 0.001). The post hoc test showed significant differences for all multiple comparisons for the surface roughness test (P < 0.001). Yet, multiple comparisons for the impact strength test revealed only a significant difference between the 1.5% BN and control groups (P= 0.005).

The addition of boron BN into PMMA improves impact strength with 1.5% concentration; while adversely increase the surface roughness.

This study aimed to find out how exposure to gaseous ozone affected heat-cured acrylic resin’s transverse and impact strengths.

Sixty samples of heat-cured acrylic resin were prepared and divided into three subgroups, control, microwave radiation (positive control), and gaseous ozone. Transverse strength and impact strength were evaluated using testing machines. At a level of significance of 5%, data were assessed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test.

Transverse strength analysis showed a significant difference among groups (P < 0.001). Post hoc test revealed significant differences between all multiple groups (P < 0.001). Impact strength analysis results showed a non-significant difference among groups (P= 0.13).

Within the limits of this research, it is possible to conclude that gaseous ozone exposure improves the transverse strength of heat-cure acrylic resin.

Microbial accumulation is still a significant problem with removable acrylic appliances. This study aimed to assess the antimicrobial properties of a self-cured acrylic resin containing curcumin nanoparticles (CNPs).

This in vitro study used 48 acrylic discs containing 0.5%, 1%, and 2% CNPs. The antimicrobial properties of the discs against Streptococcus mutans, Streptococcus sanguinis, Lactobacillus acidophilus, and Candida albicans were evaluated using disc agar diffusion (DAD), eluted component, and biofilm inhibition tests. The growth inhibition zones were measured, and the colonies were counted after 1, 3, and 7 days.

DAD test showed that none of the curcumin nanoparticle concentrations caused growth inhibition zones for any microorganisms. All the concentrations were effective against all four microorganisms in the biofilm inhibition test except 0.5% for L. acidophilus. In the eluted component test, solutions containing 2% concentration had maximum growth inhibition of all the groups at all time intervals. An increase in curcumin nanoparticle concentration from 0.5% to 1% was effective only against C. albicans.

Generally, CNPs in all concentrations were effective against the biofilms of all four microorganisms assessed in this study. Therefore, incorporating 2% CNPs into acrylic resin seems suitable for clinical use.

The B18R protein encoded by the Vaccinia virus decoys Type 1 interferons and inhibits the activity of several type I IFN members. In vitro transcription protocols benefit from this molecule’s involvement in enhancing cell viability by inhibiting interferon signal transduction. As a result of their immunomodulatory properties and potential to regenerate, mesenchymal stromal cells (MSCs) are increasingly considered an alternative treatment for a wide range of immune disorders. In this study, we investigated the modification of expression of several genes involved in immune-related pathways after preconditioning MSCs with two immune stimuli, including poly(I:C) and LPS. 

ASCs were isolated and primed with B18R, and after exposure to poly(I:C) and LPS, the expression of the same sets of genes as in the previous experiment was evaluated. Following total RNA isolation from primed cells and cDNA preparation, real-time quantitative PCR was performed for several immunomodulatory and immune-related genes, including IDO1, TDO2, COX-2, TGF-β1, TNF-α, IL-1β, IL-6, TLR3, TLR4, and MCP-1. 

Pretreatment of MSCs with poly(I:C) and LPS significantly increased the expression of all mentioned genes, while upon the B18R challenge followed by poly(I:C) and LPS treatment, they were down-regulated. Finally, it was observed that the relative expression level of IFN-β has significantly decreased in MSCs+B18R+poly(I:C) and LPS in comparison with these groups without B18R.

The data indicated that the presence of B18R prevents the overexpression of several immune-related genes, which are overexpressed in the in vitro inflammatory environment.

Henna plant (Lawsonia inermis L.) has unique properties and has long been used as an herbal remedy. In this study, polyvinyl alcohol (PVA) nanofibers containing henna extract in two different concentrations were studied to prepare a wound dressing using electrospinning. PVA polymer nanofibers using henna extract with two different concentrations of 3% and 6% were prepared by the electrospinning method. Human fibroblasts were cultured on these fibers and the mechanical and survival properties of the cells, as well as the antibacterial properties of henna were compared and evaluated. The results showed that by using of henna extract in PVA nanofibers, cell viability was significantly reduced (P≤0.05). However, the ability of nanofibers to water uptake and mechanical properties of fibers significantly increased with increasing concentrations of henna extract (P≤0.05). Nanofiber wound dressing with antibacterial properties of henna extract provides relatively fast and rapid wound healing ability. The resulting fibers are encouraging candidates for the development of improved bandaging materials.

Poly(ethylene oxide) (PEO) is the most common polymer used in commercial abuse-deterrent tablets. Due to its vulnerability to high-temperature manipulation, we investigated abuse-deterrent capability and the toxicity of this polymer upon thermal treatments at 80°C and 180°C for 1 hour.

Tablets (200 mg PEO and 300 mg Avicel®) were directly compressed under 2000 lb. The thermally manipulated PEOs were evaluated for their viscosity, crushability, structural changes, and cell toxicity.

Our findings showed that 180°C-treated tablets underwent some degrees of oxidative degradation with profound toxicity in both mesenchymal stem cells and MG63 cells. The 180°C-treated tablets exhibited almost no resistance against crushing and were prone to abuse. While thermal processing of PEO at around its melting temperature is a common approach to enhance crush resistance of its dosage forms, thermal manipulation at close to the PEO’s oxidation temperature can lead to structural changes, dramatic loss of crush and extraction resistance, and significant cell toxicity.

Similar to the low molecular weight PEO, when thermally manipulated at its thermo-oxidative temperature, the high molecular weight PEO loses its deterrence performance and causes severe cell toxicity.

 As a widely used therapeutic protein, recombinant human erythropoietin (rhEPO) is currently one of the most effective biopharmaceuticals on the market for the treatment of anemia in patients with chronic renal disease. Increasing in vivo rhEPO half-life and its bioactivity is a significant challenge. It was hypothesized that the application of self-assembly PEGylation retaining activity, named supramolecular (SPRA) technology, could prolong the protein half-life without a significant loss of bioactivity.

 This study aimed to assess the stability of rhEPO during synthetic reactions, including the conjugation with adamantane and the formation of the SPRA complex. To do this, the secondary structure of the protein was also evaluated.

 FTIR, ATR-FTIR, Far-UV-CD, and SDS-PAGE methods were employed. Thermal stability studies of SPRA-rhEPO complex and rhEPO were investigated at 37°C for ten days using a nanodrop spectrophotometer.

 The secondary structure of lyophilized rhEPO, AD-rhEPO, and rhEPO (pH 8) was compared to rhEPO. Results showed that the secondary structure of the protein was unaffected by lyophilization, pH change, and the formation of covalent bonds in conjugation reaction. SPRA-rhEPO complex was also stable for seven days in phosphate buffer (pH 7.4) at 37°C.

 It was concluded that the stability of rhEPO could increase by complexation using SPRA technology.

Many countries are presently concerned about providing a safe vaccine with minimal side-effects against COVID 19. Here, we aimed to develop a multiepitope vaccine by utilization of spike, envelope, nucleocapsid and membrane proteins of SARS-CoV-2 virus.

Online servers were employed for forecasting the most robust B-cell, T-cell and IFN-γ epitopes to stimulate the immune system. Then the top selected epitopes alongside the sequence of Heparin-Binding Hemagglutinin Adhesin (HBHA) protein were applied to design a novel multiepitope vaccine, bioinformatically. The physicochemical characteristics and the protein structures of the proposed vaccine were defined using online tools. The docking process between Toll-like Receptor 4/Myeloid Differentiation Factor 2 (TLR4/MD2 receptor) and the designed recombinant structure was also investigated.

The designed construct had -0.210 GRAVY and 36.39 instability indices which make it theoretically stable. The designed construct was predicted to be soluble and non-allergenic. The approximate half-life of the proposed structure was computed 30 hours in mammalian reticulocytes and more than 10 hours in Escherichia coli. In its tertiary structure, 93% of the residues were in the core region and had a score of 52.73 for 3D verification and -5.55 for Z-score. Protein-protein docking of HBHA and TLR4/MD2 receptor was successful with the lowest energy of -1310.6 kcal/mol.

The bioinformatics evaluations indicate that the designed structure is stable and immunogenic for development of a protein-based subunit vaccine against COVID-19.

One of the main challenges in protein-based vaccines is the poor immunogenicity of antigens, which can be solved by the use of adjuvants. Advax is a novel microparticle polysaccharide adjuvant that in combination with antigens can induce both cellular and humoral immunity based on the intrinsic features of the antigen. It has been shown that poly(I:C) can be a suitable adjuvant for the PfMSP-142-based malaria vaccine. Advax is a suitable co-adjuvant for poly(I:C) to increase its half-life and reduce dose-dependent toxicity. To investigate whether advax alone or advax /poly(I:C) combination can enhance the immunogenicity with increased parasite inhibitory anti-PfMSP-142 antibodies in comparison to poly(I:C). Mice groups were inoculated with rPfMSP-142 alone or formulated in poly(I:C), poly(I:C)/advax, or advax. Then, humoral and cellular immune responses, the ratio of Th1/Th2 and growth inhibitory activity of induced antibodies were analyzed. Poly(I:C)/advax formulated PfMSP-142 induced higher levels of anti-PfMSP-142 IgG, IgG2a, and IgG2b antibodies relative to poly(I:C)-formulated PfMSP-142. The maximum ratio of IFN-γ/IL-4 (50.13) and gG2a/IgG1 (2.65), was induced in mice received advax-formulated PfMSP-142. Besides, poly(I:C)/advax formulated PfMSP-142 induced a higher ratio of IFN-γ/IL-4 (25.33) and IgG2a/IgG1 (1.89) when compared withpoly(I:C) alone. Strong growth inhibitory activity was observed inantibodies induced in mice receivedpoly(I:C)/advax-formulated PfMSP-142. These findings indicate that advax is a favorable adjuvant to be combined with poly(I:C), and this combination of adjuvants could induce Th1 immune responses and growthinhibitory antibodies against rPfMSP-142.

This study was designed to fabricate a suitable permanent scaffold for the normal aligned myotube formation and improve the process of myogenic differentiation of selected stem cells.

In this experimental study, an engineered scaffold composed of decellularized human amniotic membrane (DHAM) and electrospun fibers of poly(ε-caprolactone) (PCL) was fabricated and characterized. PCL nanofibers were superimposed on DHAM (PCL-DHAM) in two different patterns, including randomized fibers (Random) and aligned fibers (Aligned). Adipose derived stem cells (ADSCs) were isolated from adult Wistar rats and cultured on designed scaffold and induced to myotube differentiation. Using an MTT assay, the vitality of cells was determined. Then, myogenic cell differentiation was assessed using scan electron microscopy (SEM), immunofluorescence assay, and reverse transcription-polymerase chain reaction (RT-PCR).

The mechanical properties of engineered PCL-DHAM composite improved significantly compared to DHAM as a control. The engineered PCL-DHAM promoted cell growth and high expression of myosin, Mhc2 and myogenin and thus enhanced the myotube formation.

These findings revealed that bio-composite membrane prepared from PCL nanofibers and DHAM, may represent a promising biomaterial as a desirable scaffold for applying in the bioengineered muscle repair.

Nanoparticles are used mainly for the transmission of the therapeutic molecules (like drugs, proteins, or DNA) to the organ/tissue of human body. Polymeric nanoparticles are mostly applied for therapeutic effectiveness in cancer therapy. The micro environment of tumor tissues in vessels can assist nanoparticles in achieving their anticipated accumulation. Poly (lactic acid)(PLA) is a novel green polymer with natural sources (like sweet potato and sugar cane). PLA is a linear aliphatic which has great sustainability, renewability and compostability. PLA has popper mechanical, thermal and barrier properties. This biomaterial is thermoplastic polyester with biocompatibility, non-toxicity and biodegradability. Various forms of PLA nanoparticles are synthetized for biomedical applications like cancer treatments and wound healing process. This review article introduces the various structures of polylactic acid nanoparticles used to deliver anticancer drugs. Furthermore, the investigational approaches that are considered for using PLA nanoparticles in treatment of different types of cancers will be reported briefly.

 Composite restoration failures may occur because of different factors. In these situations, the repair of a composite restoration has many advantages over replacement such as saving time, lower cost, and lower risk of excessive removal of sound tooth structure and subsequent pulp exposure.

The purpose of this in vitro study was to evaluate the effects of two surface treatments on shear bond strength (SBS) of new composite to old composite.

In this in vitro study ,60 composite discs were fabricated using a plexiglass mold measuring 4 mm in thickness and 7 mm in diameter, and were randomly divided into three groups (n=20). In group 1, the bonding procedure was done with no modification. After roughening of one surface in all remaining samples, chloroform (CHCl3) was applied on the surface of samples in group 2 and phosphoric acid 35% was applied on the surface of the samples in group 3. PermaSeal was then applied in all samples and new composites were bonded to the surface. The samples were stored in distilled water for one week and were then subjected to 500 thermal cycles and shear bond strength between two layers of composite and mode of failures were evaluated.

The lowest and the highest SBS values of repair composite to old composite were noted in groups 3 and 1, respectively and this difference was statistically significant (p < 0.05).The difference between groups 1 and 2 was not significantly different (p = 0.197). The mode of failure was mixed in all samples of groups 2 and 3 and cohesive in group 1.

After grinding, the surface treatment with phosphoric acid did not increase the SBS of new composite to old composite, while chloroform increased the SBS almost to the level of the baseline in control group.

Activation of hepatic stellate cells (HSCs) is an important driver of liver fibrosis, which is a health problem of global concern, and there is no effective solution for it at the present. Senescent activated HSCs are preferentially killed by natural killer cells (NK cells) to promote the regression of hepatic fibrosis.

The purpose of this study was to investigate the effect of polyinosinic-polycytidylic acid (poly I:C) on HSCs’ senescence, a trigger for NK cell-induced cytotoxicity.

The senescence of HSCs was assessed by western blot, qRT-PCR, and flow cytometry, and NK cell cytotoxicity was assessed in a co-culture of NK cells with poly I:C-treated HSCs by measuring CD107a expression.

The expression of p16, p21, SA--gal, MICA/MICB, and ULBP2 increased in poly I:C-treated HSCs, rendering them significantly susceptible to NK cell cytotoxicity.

Poly I:C induces cellular senescence in HSCs and triggersNKcellimmunosurveillance, suggesting that the role of poly I:C in HSC senescence may promote fibrosis regression.

In this study, the magnetic 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) – poly (4-vinylpyridine) (P4VP) was synthesized and characterized. Removal of Molybdenum (Mo) from aqueous solutions using prepared material as nanosorbent was investigated. The magnetic P4VP was prepared by copolymerization of P4VP with TMSPMA. The prepared adsorbent was characterized by various techniques including the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The batch adsorption technique was applied and the effect of several important parameters such as pH of the aqueous solution, adsorbent dose, initial Mo(VI) concentration, contact time, and temperature was evaluated. Desorption behavior of Mo(VI) and the effect of foreign ions (Cd2+, Ca2+, Co2+, Fe3+, Ba2+ and Pt4+) in real samples were also investigated. Co (II) and Pt (IV) had a greater impact on the adsorption process than other foreign ions. The maximum capacity for Mo(VI) adsorption on the prepared adsorbent was 4.87 mg/g, which was obtained at a temperature of 40°C with an initial concentration of 10 mg/L of Mo(VI). The adsorption isotherms were best fitted with the Weber Van Vliet isotherm model. The kinetic data were fitted well with the pseudo-second-order equation with a high correlation coefficient (R2 > 0.99). Based on the negative standard Gibbs free energy change (ΔG° < 0) and the positive standard enthalpy change (ΔH° > 0), it was found that the adsorption was an endothermic and a spontaneous process in nature