Effects of PLGA nanofibrous scaffolds structure on nerve cell directional proliferation and morphology

Electrospinning has been recognized as an efficient technique for the fabrication of neural tissue engineering scaffolds. Many approaches have been developed on material optimization, electrospinning techniques, and physical properties of scaffolds to produce a suitable scaffold for tissue engineering aspects. In this study, structural properties of scaffolds were promoted by controlling the speed of fiber collection without any post-processing. PLGA scaffolds, in two significantly different solution concentrations, were fabricated by the electrospinning process to produce scaffolds with the optimum nerve cell growth in a desired direction. The minimum, intermediate and maximum rate of fiber collection (0.4, 2.4, 4.8 m/s) formed Random, Aligned and Drown-aligned fibers, with various porosities and hydrophilicities. The scaffolds were characterized by fiber diameter, porosity, water contact angle and morphology. Human nerve cells were cultured on fiber substrates for seven days to study the effects of different scaffold structures on cell morphology and proliferation, simultaneously. The results of MTT assay, the morphology of cells and scaffold characterization recommend that the best structure to promote cell direction, morphology and proliferation is accessible in an optimized hydrophilicity and porosity of scaffolds, which was obtained at the collector linear speed of 2.4 m/s.     

Matrix-fibril morphology development of polypropylene/poly(butylenes terephthalate) blend fibers at different zones of melt spinning process and its relation to mechanical properties

Different shapes of dispersed phase such as sphere, laminar and fibrillar can form in the matrix phase of polymer blends. Production of blend fibers in melt spinning process can result more effective in fibrillar phase morphology formation than in other processes. In this research, the matrix-fibril morphology development during the melt spinning of polypropylene/poly(butylenes terephthalate) was studied. The shapes of blend dispersed phase collected from different zones of the melt spinning line were evaluated by scanning electron micrographs (SEM) and rheological mechanical spectra (RMS). The results showed that fibrillar shape could not be created in the PP/PBT blend fiber samples exited from the spinneret orifice (gravity spun fibers) at low contents (5 percent) of the PBT dispersed phase. However, a complete fibrillar structure was formed in all the as-spun PP/PBT blend fiber samples (melt drawn). The rheological evaluations confirmed a network structure resulting from fibril formation for the samples with high contents (20–40 %) of the PBT dispersed phase and the formation of spherical shape with low contents (5–10 %) of the PBT dispersed phase in matrix of the blend fibers. It was observed that the flow fields of processing zones and blend ratio, in producing the blend fibers, have intensive effects on morphological variations; besides there was a strong relation between the mechanical and morphological properties.     

Effects of Some Organic Nitrogen Sources and Antibiotics on Callus Growth of Indica Rice Cultivars

A factorial experiment based on a completely randomized design with three replicates was conducted to evaluate effects of sixteen different mixtures of organic nitrogen sources and antibiotics which were supplemented to an Murashige and Skoog (MS) medium containing 4 mg L^?1 2,4-Dichlorophenoxyacetic acid (2,4-D), 0.4 mg L^?1 benzyl-aminopurine (BAP), 30 g L^?1 sucrose, 8 g L^?1 Agar-agar on fresh weight and dry weight (assessed after three days of drying at 70°C) of calli and in vitro callogenesis from scutellum of four indigenous Iranian Indica rice (Oryza sativa L.) cultivars, including ‘Hashemi’, ‘Gerdeh’, ‘Hasani’, and ‘Gharib’. It was found that proline at 2.8 g L^?1 is the most effective source of organic nitrogen in enhancing growth, whereas asparagine at 0.75 g L^?1 inhibited the calli growth. Hygromycin at 50 mg L^?1, with slight differences between the cultivars, could effectively stunt the growth of untransformed calli. Mixture of cefotaxime (250 mg L^?1) and vancomycin (250 mg L^?1) did not have any significant effects on calli growth, although this treatment was slightly phytotoxic.     

Identification of Sequence Variation in the Apolipoprotein A2 Gene and Their Relationship with Serum High-Density Lipoprotein Cholesterol Levels

Background:

Apolipoprotein A2 (APOA2) is the second major apolipoprotein of the high-density lipoprotein cholesterol (HDL-C). The study aim was to identify APOA2 gene variation in individuals within two extreme tails of HDL-C levels and its relationship with HDL-C level.

Methods:

This cross-sectional survey was conducted on participants from Tehran Glucose and Lipid Study (TLGS) at Research Institute for Endocrine Sciences, Tehran, Iran from April 2012 to February 2013. In total, 79 individuals with extreme low HDL-C levels (≤5^th percentile for age and gender) and 63 individuals with extreme high HDL-C levels (≥95^th percentile for age and gender) were selected. Variants were identified using DNA amplification and direct sequencing.

Results:

Screen of all exons and the core promoter region of APOA2 gene identified nine single nucleotide substitutions and one microsatellite; five of which were known and four were new variants. Of these nine variants, two were common tag single nucleotide polymorphisms (SNPs) and seven were rare SNPs. Both exonic substitutions were missense mutations and caused an amino acid change. There was a significant association between the new missense mutation (variant Chr.1:16119226, Ala98Pro) and HDL-C level.

Conclusion:

None of two common tag SNPs of rs6413453 and rs5082 contributes to the HDL-C trait in Iranian population, but a new missense mutation in APOA2 in our population has a significant association with HDL-C.     

Pre- and post-McDonald cerclage cervical length, width and funneling rate and their association with duration of pregnancy

Changes of cervical ultrasonographic physical parameters and their association with outcome of cerclage have not been fully elucidated. This study aimed at evaluating association between ultrasonographic physical cervical shapes before and after McDonald cerclage with the length of pregnancy. Cervical length, width and funneling rate were assessed by transvaginal ultrasonography before and after the procedure. Mean pre-cerclage cervical length, width and funneling rate were 29.28 +/- 5.54, 19.92 +/- 10.30 mm and 12.90 +/- 18.87%, respectively. The mean post-cerclage cervical length, diameter and funneling rate were 31.68 +/- 4.21, 9.78 +/- 13.86 and 4.32 +/- 10.89%, respectively (p < 0.001 for all pre- and post-cerclage changes). The mean post-cerclage duration of pregnancy was 19.78 +/- 5.94 weeks. There were significant direct correlations between the pre-and post-cerclage cervical lengths with pregnancy duration (r = 0.24, p = 0.04 and r = 0.44, p < 0.001, respectively). There were significant indirect correlations between the pre- and post-cerclage funneling rate with pregnancy duration (r = -0.30, p = 0.01 and r = -0.20, p = 0.01, respectively). Similar correlations were not significant for the cervical widths. This study showed that the pre- and post-cerclage ultrasonographically determined cervical length and funneling are good predictors of pregnancy duration.     

Impact of ABCB1 Gene Polymorphisms and Smoking on the Susceptibility Risk of Chronic Myeloid Leukemia and Cytogenetic Response

Background:IM, a strong and selective TKI, has been approved as the front line of treatment in CML patients. In spite of satisfactory results of imatinib in the treatment of patients with CML, patients with treatment failure or suboptimal response developed resistance that might be because of pharmacogenetic variants. This study attempted to evaluate the influence of ABCB1 gene polymorphisms and smoking on CML risk and resistance to imatinib. Methods: ABCB1 (c.1236C>T, c.3435C>T) polymorphisms were genotyped in 98 CML patients and 100 sex- and age-matched healthy subjects by PCR-RFLP method, followed by sequencing. The patients were evaluated for cytogenetic response by the standard chromosome banding analysis in regular intervals. Results:Our results showed that c.1236CC genotype was significantly associated with imatinib resistance (OR = 3.94; p = 0.038). Analysis of the joint of SNP-smoking combination showed that smokers with c.1236TT/CT and c.1236CC genotypes had the increased risk of CML (OR = 6.04; p = 0.00 and OR = 4.95, p = 0.005) and treatment failure (OR = 5.36, p = 0.001 and OR = 15.7, p = 0.002), respectively. Smokers with c.3435TT/CT and c.3435CC genotypes also displayed the elevated risk of CML development (OR = 6.01, p = 0 and OR = 4.36, p = 0.011) and IM resistance (OR = 5.61, p = 0.001 and OR = 13.58, p = 0.002), respectively. Conclusion:Our findings suggest that c.1236CC genotype has clinical importance in the prediction of treatment outcome with IM, and smoking could have a synergistic role in CML risk and IM resistance. Key Words: ATP binding cassette transporter subfamily B, Imatinib mesylate, Smoking     

Application of machine-learning models for diagnosing health hazard of nitrate toxicity in shallow aquifers

There is a growing concern about health hazards linked to nitrate (NO₃) toxicity in groundwater due to overuse of nitrogen fertilizers in rice production systems of northern Iran. Simple-cost-effective methods for quick and reliable prediction of NO₃ contamination in groundwater of such agricultural systems can ensure sustainable rural development. Using 10-year time series data, the capability of adaptive neuro-fuzzy inference system (ANFIS) and support vector machine (SVM) models as well as six geostatistical models was assessed for predicting NO₃ concentration in groundwater and its noncarcinogenic health risk. The dataset comprised 9360 water samples representing 26 different wells monitored for 10 years. The best predictions were found by SVM models which decreased prediction errors by 42–73 % compared with other models. However, using well locations and sampling date as input parameters led to the best performance of SVM model for predicting NO₃ with RMSE = 4.75–8.19 mg l^?1 and MBE = 3.3–5.2 mg l^?1. ANFIS models ranked next with RMSE = 8.19–25.1 mg l^?1 and MBE = 5.2–13.2 mg l^?1 while geostatistical models led to the worst results. The created raster maps with SVM models showed that NO₃ concentration in 38–97 % of the study area usually exceeded the human-affected limit of 13 mg l^?1 during different seasons. Generally, risk probability went beyond 90 % except for winter when groundwater quality was safe from nitrate viewpoint. Noncarcinogenic risk exceeded the unity in about 1.13 and 6.82 % of the study area in spring and summer, respectively, indicating that long-term use of groundwater poses a significant health risk to local resident. Based on the results, SVM models were suitable tools to identify nitrate-polluted regions in the study area. Also, paddy fields were the principal source of nitrate contamination of groundwater mainly due to unmanaged agricultural activities emphasizing the importance of proper management of paddy fields since a considerable land in the world is devoted to rice cultivation.     

Dyeing behavior of polyacrylonitrile nanofibers: Physicochemical parameters of dyeing with basic dye in comparison with regular polyacrylonitrile fibers

Polyacrylonitrile nanofibers were produced using the electrospinning method and dyed with a basic dye alongside regular polyacrylonitrile fibers. In order to investigate the effect of high surface area to volume ratio of nanofibers on their adsorption behavior in comparison with regular fibers, the dyeing conditions for both types of fibers were kept just the same. Physiochemical parameters of dyeing such as adsorption isotherm, standard affinity, enthalpy change, rate of dyeing constant, diffusion coefficient, and activation energy of diffusion were investigated for both types of fibers. The results showed that the adsorption process can be well described with the Langmuir adsorption isotherm for both types of fibers whereas the standard affinity of dye to nanofibers was higher than regular fibers and the higher negative values of enthalpy changes were obtained for regular fibers. The nanofibers rate of dyeing was faster than regular fibers with higher amounts of diffusion coefficients and lower amounts of activation energy of diffusion. This study also revealed that in spite of the approximately same amount of dye exhaustion for both types of fibers, the color strength of regular fibers was noticeably higher than nanofibers.     

Nitrogen loss and its health risk in paddy fields under different drainage managements

Subsurface drainage is a prerequisite for year-round crop production in a large area of northern Iran^, s paddy fields. Minimizing environmental and health issues related to nitrogen (N) losses through subsurface drainage systems provides suitable condition for sustainable agriculture in these fields. A field study was conducted to evaluate nitrogen loss and its health risk in the conventional and subsurface-drained paddy fields. Ammonium, nitrate, and total N concentrations of subsurface drainage effluents, surface runoff, and leachates were monitored during three successive rice-canola-rice growing seasons from July 2011 to August 2012. Different components of N balance and health risk of nitrate leaching to groundwater were also investigated. Ammonium in drainage effluents collected during the experimental period ranged from approximately zero to 1.72 mg L^?1, while nitrate fluctuated from 0.5 to 28.6 mg L^?1. Average nitrate concentration in leachates of subsurface-drained area was 7.7–81.4 % higher than that in subsurface drainage effluents, while it was 126.8 % higher than that in surface runoff for the conventional field. Subsurface drainage provided a better utilization of soil N through providing winter cropping and reduced the potential for non-carcinogenic risks of nitrate leaching to groundwater. The results are encouraging for producers engaged in rice-canola production in the study area with respect to the environment and human health quality.