سال:1396 | دوره: | شماره: |تعداد مقالات:9

Skin substitutes help skin repair and regeneration, and restore the efficient properties of skin in the time of acute burn injuries or other chronic skin lesions. They can act as permanent skin replacements or temporary wound covers, depending on their composition and design. Recent studies have overcome some obstacles, but till today no ideal skin substitute has been developed. The aim of this study is to introduce some commercially available and under development products and also to provide information about these substitutes and their limitations in order to use native-like skin substitute design and production. Currently the accessible skin substitutes have several limitations such as infection risk, reduced vascularization and lack of integration to host tissue. The absence of various cells which are responsible for temperature control and insulation, pigmentation, immune regulation and nerve supply is among the mentioned limitations. Further researches will be required to resolve different issues and suggest practical solutions toward a true skin substitute with excellent engraftment and durable viability. In addition, availability and awareness of these skin substitutes in developing countries is not adequate in spite of the number of cases requiring this kind of treatment, therefore, it is needed to develop indigenous economical technology to promote available treatments in hopes of achieving substitutes with higher quality and reasonable cost available to a greater percentage of patients.

Post-surgery infections and not effective integration represent a serious issue in the Titanium (Ti) based implants function for a long term stability. To reduce such issue various surface functionalization method including surface coating has been explored. Here we successfully coated Ti substrates with Graphene Oxide (GO), Chitosan (Cs), and nanocomposite of GO and Cs (GO/Cs) via spin coated method to evaluate the osteogenic properties of each coatings. Uncoated Ti substrates were used as control. Scanning electron microscopy was used to investigate the coating morphology. Surface roughness measurements were achieved from atomic force microscopy. To measure surface wettability, contact angels method was performed.Ti substrates coated with Cs (TiCs) and Cs/GO (TiCs/GO) showed the highest surface wettability compared to Ti substrates coated with GO (TiGO) and the control. The highest surface roughness was also observed in TiCs/GO. To test cellular attachment and proliferation the samples were exposed to human osteoblast-like MG63 cells after 2 hours, 4 hours, 6 hours, 1 day, 3 days, and 1 week. MTT [3-4, 5 dimethylthiazol- 2yl (2, 5diphenyl-2H-tetrazoliumbromide)] assay was performed to measure the percentage of cellular attachment and proliferation for each coatings. Cell adhesion and cell proliferation was most improved in TiCs followed by TiCs/GO. Corrosion resistance of the coatings was investigated using potentiodynamic polarization test in simulated body fluid. The result indicated that the nanocomposite coating could provide effective protection of Ti substrates from corrosion.

Staphylococcus aureus is one of the most important pathogens in hospital acquired infections. Annually, many people are infected with S. aureus in hospitals.Rapid detection of this bacterium is extremely helpful in preventing and managing this bacterium mediated diseases. Aptamers are powerful probes, which can be used as a target explorer in a wide range of diagnostic systems. To isolate a specific aptamer against S. aureus, a library of single-stranded DNA molecules was designed, and enriched through Cell-SELEX procedure. In the Cell-SELEX, the DNA library was exposed to the S. aureus bacterium in 8 reiterative quadruple rounds including: binding, separation, elution and amplification. After 8 rounds, the PCR product was cloned and sequenced. Cloned aptameric sequences were evaluated through enzyme-linked oligonucleotide assay (ELONA), and a sequence with the best outcomes was selected as ideal aptamer. Eight rounds of Cell-SELEX procedure led to isolation of a specific ssDNA aptamer against S. aureus and named as “STAPT” (conflation of STAphylococcus and APTamer). Using ELONA technique, the detection limit of this aptamer was determined as 4×103 CFU/ml.The aptamer “STAPT” showed the promising and potent abilities and features to be utilized as a bio-detection element likely in advanced detection systems. Although more extended researches are needed for this purpose.

Gasoline containing different chemical compounds especially aromatic compounds such as benzene, xylene, toluene and ethylbenzene which are the most dangerous compounds. Gas station workers have the highest potential for exposure to gasoline evaporation. Many studies have investigated the effect of gasoline vapors and cause of death in people working in gas stations. According to reports, the cause of death of these people is mainly due to cardiovascular disease, lung cancer, leukemia and other cancers in the world. With regard to the harmful effects of gasoline vapors on health and the importance of the relationship between the immune system and nervous, in this study we investigated alternations in gene expression pattern of the serotonin 5-Hydroxytryptamine 2A (5-HT2A) receptor and type A gammaaminobutyric acid (GABAA) receptor in peripheral blood mononuclear cells (PBMCs) of people working in gas stations, Tehran. For this purpose, The PBMCs were separated from whole blood of 30 gas station workers and 30 normal by Ficoll- hypaque. The total RNA was extracted and the cDNA was synthesized. This process was followed by Real-time PCR using specific primers for 5-HT2A and GABAA receptor mRNAs. Results have shown a significant increase (P=0.001) in relative gene expression of 5-HT2A receptor whereas relative expression of GABAA receptor was significantly decreased (P=0.004) in PBMC compared with normal control peoples. According to the role of the serotonin in asthma and due to the importance of the activity of this neurotransmitter through 5HT2A receptor which has a significant increase in patients with allergic asthma it can be concluded that workers in the gas station may be more susceptible to developing allergic asthma.On the other hand, low expression of GABAA receptor is associated with mental health problems such as depression, so it can also be concluded that people working at the gas station are more exposed to these health problems in comparison to normal people.

Valerenic acid (VA) as a sesquiterpene constituent responsible for medicinal properties is derived from valerian (Valeriana officinalis). It is well documented that the mutualistic basidiomycete Piriformospora indica substantially promotes secondary metabolites production. Nevertheless, our knowledge about the molecular mechanism involved is rudimentary. In this study, we aimed to find the effect of P. indica cell wall extract (CWE) in the modulation of the transcriptional rate of sesquiterpene synthase (Sesqui-TPS) genes involved in VA biosynthesis in the host plant, V. officinalis. For this purpose, relative expression of putative terpene syntheses (VoTPS1, VoTPS3 and VoTPS7) genes was quantified by quantitative realtime PCR in the roots of valerian plants inoculated by two concentrations of the extract (2 and 4 % v/v) prepared from the cell wall of P. indica for various time intervals. As well as, VA content of roots of V. officinalis was measured. According to the results, The 4% fungal CWE application produced more VA than 2% CWE treated plants at the exposure time of 72 h. Such enhancement was correlated with increased transcript expression of two sesquiterpene synthases (sesqui-TPSs) including VoTPS1 and VoTPS7 which provided intermediates probably serving in the VA-biosynthetic pathway, while different expression pattern of VoTPS3 showed that it probably has no influence on the biosynthesis of VA.Since the accumulation of VA is a dose (and time) dependent response at roots of V. officinalis, the present study suggests that the mechanism (s) responsible for the enhancement of VA could be related to the fungus-plant association.

Poppy (Papaver somniferum) is the most important commercial source of analgesic drugs and of compounds related to them. Because of the excellent medicinal properties of poppy, finding genotypes with changed alkaloid content through breeding or by producing transgenic plants in tissue culture has attracted great interest. The present research was conducted to optimize rooting in somatic embryos of transgenic poppy plants. Sensitivity of hypocotyl explants to the antibiotic paromomycin was first determined in kill-curve experiments. Transformation of the hypocotyl explants was carried out using the GV3101 strain of Agrobacterium tumefaciens having the vector with the NPT II gene. The explants were then transferred to MSbased medium containing the 2, 4-D plant growth regulator (PGR) at 1 mg/L, 10 mM MES, and paromomycinat 15 mg/L. After the somatic embryos were produced, a factorial experiment was conducted in the rooting stage with two factors including medium (MS and 1.2 MS) and PGR (500 mM IBA PGR and no PGR).Also, confirmation of derived transgenic plantlets was confirmed by PCR technique.Results of ANOVA and comparison of the means indicated the highest rooting percentage happened in the 1.2 MS medium containing the IBA.

Lemongrass (Cymbopogon olivieri) is highly cross-pollinated and fragrant herb plant. Because of so worthy essential oil components, it is widely used in cosmetics, food, and medicine industry. The C. olivieri leaves of 4 populations were sampled from South and Southeast Iran. Random amplified polymorphic DNA (RAPD) markers used to assess the population structure and genetic variation. In total, 32 polymorphic bands amplified from 11 effective chosen RAPD markers.Cluster analysis using UPGMA method divided the populations into 2 main groups.A high cophenetic correlation coefficient (r=0.90) was obtained. The pale yellow essential oils were used for GC-MS analysis. Pipertone, carrene, elemol, limonene, benzene, α-pinene, linalool, azulene and calarene were the components with the highest amount found in this study. The high genetic and phytochemical diversity among studied C. olivieri population was observed which could be applied in following breeding and gene bank conservation programs.

Bio-based polymers have attracted significant attentions because of their renewable nature which can be a substitute of petroleum-based polymers; moreover, such polymers do not pollute the environment due to their degradable nature. In this research, the poly lactic acid (PLA) and poly-3-hydroxybutyrate (PHB) blend, as biodegradable polymers, behavior was investigated. Different ratios of PLA/PHB blend were prepared using solution casting method in the presence of the pyromellitic anhydride (PMDA) as acompatibilizer. DSC results revealed that the PMDA presence caused to separation of a-helix crystals and b-plate in two polymers resulting in phase separation via altering the crystallinity rate. PMDA can control the crystallization phenomenon which affected the crystallization rate, percentage and crystal size. Low molecular interaction was observed using the XRD results of pure and blended samples. SEM images of samples with higher content of PLA illustrated the homogeneous dispersion of PHB. Ring opening reaction of PMDA resulted in increasing the acidic number of samples which indicated the weak interaction with active group of polymers. It was observed no shit in IR peaks which indicated the incompatibility of these two polymers. Results shed light on the PMDA behavior in PLA/PHB blend which PMDA in spite of controlling the crystallinity behavior of the blend, cannot improve the compatibility and mixing.

A feasible and fast method for Adult Hemoglobin (A-Hb) and Fetal Hemoglobin (F-Hb) study was developed by immobilization of Hb on gold-coated magnetic iron oxide nanoparticles (GMNPs).The prepared GMNPs composite nanoparticles with 60 nm diameter were used as a carrier for the immobilization of Hb. The A-Hb and F-Hb were physically attached to the GMNPs nanoparticles. The direct electrochemistry of F-Hb and A-Hb showed a quasi-reversible cyclic voltammogram corresponding to the Heme group with a formal potential of 314 and -334 mV in 0.1M PBS (pH 6.2), respectively. The apparent charge transfer rate constant (ks) and transfer coefficient (a) for electron transfer between the electrode surface and protein were calculated as 0.29/s and 0.1 for F-Hb and 0.21/s and 0.47 for A-Hb. The linear concentration rangesare17.3–225 and 7.4-53 mM for F-H band A-Hb biosensors for H2O2 detection. The lifetime of biosensor is more than 2 weeks.