Electrodynamic droplet actuation for lab on a chip system

This work presents the development of electrowetting on dielectric and liquid dielectrophoresis as a platform for chemistry, biochemistry and biophysics. These techniques, typically performed on a single planar surface offer flexibility for interfacing with liquid handling instruments and performing biological experimentation with easy access for visualisation. Technology for manipulating and mixing small volumes of liquid in microfluidic devices is also crucially important in chemical and biological protocols and Lab on a Chip devices and systems. The electrodynamic techniques developed here have rapid droplet translation speeds and bring small droplets into contact where inertial dynamics achieve rapid mixing upon coalescence.In this work materials and fabrication processes for both electrowetting on dielectric and liquid dielectrophoresis technology have been developed and refined. The frequency, voltage and contact angle dependent behaviour of both techniques have been measured using two parallel coplanar electrodes. The frequency dependencies of electrowetting and dielectrophoretic liquid actuation indicate that these effects are high and low-frequency limits, respectively, of a complex set of forces. An electrowetting based particle mixer was developed using a custom made electrode array and the effect of varying voltage and frequency on droplet mixing was examined, with the highest efficiency mixing being achieved at 1 kHz and 110 V in about 0.55 seconds.A composite electrodynamic technique was used to develop a reliable method for the formation of artificial lipid bilayers within microfluidic platforms for measuring basic biophysical aspects of cell membranes, for biosensing and drug discovery applications. Formation of artificial bilayer lipid membranes (BLMs) was demonstrated at the interface of aqueous droplets submerged in an organic solvent-lipid phase using the liquid dielectrophoresis methods developed in this project to control the droplet movement and bring multiple droplets into contact without coalescence. This technique provides a flexible, reconfigurable method for forming, disassembling and reforming BLMs within a microsystem under simple electronic control. BLM formation was shown to be extremely reliable and the BLMs formed were stable (with lifetimes of up to 20 hours) and therefore were suitable for electrophysiological analysis. This system was used to assess whether nanoparticle-membrane contact leads to perturbation of the membrane structure. The conductance of artificial membranes was monitored following exposure to nanoparticles using this droplet BLM system. It was demonstrated that the presence of nanoparticles with diameters between 50 and 500 nm can damage protein-free membranes at particle concentrations in the femtomolar range. The effects of particle size and surface chemistry were also investigated. It was shown that a large number of nanoparticles can translocate across a membrane, even when the surface coverage is relatively low, indicating that nanoparticles can exhibit significant cytotoxic effects

Up regulation of long non-coding RNAs BACE1 and down regulation of LINC-PINT are associated with CRC clinicopathological characteristics

Background Long non-coding RNAs (LncRNAs) are known to have regulatory consequences for aberrant gene expression in cancers. The aim of this study was to evaluate the expression levels of long non-encoding RNAs, BACE1 (β-secretase1) and LINC-PINT (Long Intergenic Non-Protein Coding RNA, P53 Induced Transcript), in colorectal cancer (CRC) with clinicopathological parameters. Methods and results Bioinformatics analysis defining effectual signalling pathways Wnt. A total of 130 tissue samples (50 fresh CRC tissues with parallel adjacent normal tissues (ADJ) accompanied with 30 normal healthy control tissue samples) were collected from the Iranian population. mRNA expression analysis was performed via Real Time Q-PCR. Statistical analysis for comparing CRC expression levels with ADJ and normal healthy tissues were carried out using Kruskal–Wallis tests. The Receiver Operating Characteristic (ROC) curve was plotted for each LNC, separately. We discovered that PINT and BACE1 expression levels were decreased and increased respectively in CRC tumour samples compared with ADJ normal and healthy tissues. Clinicopathological parameter assessment revealed a significant relationship between PINT expression, tumour location, staging and distant metastasis (p < 0.009, p < 0.014, p < 0.008, respectively). Also, BACE1 over expression was significantly associated with tumour site (p < 0.009), metastasis (p < 0.017) and histological differentiation (p < 0.028) and staging (p < 0.017). Furthermore, ROC curve plotting showed LINC-PINT LNC-BACE1 may distinguish between early and late-stage of CRC, highlighting the value of both BACE1 and PINT as CRC progression biomarkers. Conclusion We investigated two LNCRNAs (PINT and BACE1) as potential CRC prognostic biomarkers, which are imperative for early and effective medical intervention in CRC. Expression levels of PINT and BACE1 in CRC tissue samples may serve to identify metastasis earlier, increasing patient survival rates and expediating clinical treatment options

Can Giardia Infection Impair the Diagnostic Level of Fecal Calprotectin in Patients with Inflammatory Bowel Disease? A Case Report

Inflammatory bowel disease (IBD) is attributed to complex conditions of gastrointestinal tract that is frequently reported all over the world. Fecal calprotectin evaluation is described as a primary tool to screen IBD patients. There are reports showing the confounding role of some microbial agents in diagnostic levels of calprotectin. A 32-yr-old woman with symptoms like IBD/IBS (irritable bowel syndrome); admitted to IBD Clinic of Behbood Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Jan 2017 for evaluation of the level of fecal calprotectin. In spite of high level of calprotectin, trophozoite of Giardia intestinalis was observed in direct examination of stool sample. Microbial pathogens can lead to false elevation of fecal calprotectin and misdiagnosis of gastrointestinal patients suspected to IBD

Prevalence of gluten-related disorders in Asia-Pacific region: a systematic review.

Background & Aims: The epidemiology of gluten-related disorders (GRDs) is still an open field to be explored. We conducted this systematic review based on the current epidemiology knowledge of GRDs, focusing on the changing prevalence of GRDs reported in the Asia-Pacific region.Methods: We searched Medline, PubMed, Scopus, Web of Science and Cochrane database with the following MeSH terms and keywords: celiac disease (CD), wheat allergy (WA), non-celiac gluten sensitivity (NCGS), dermatitis herpetiformis (DH) and gluten ataxia (GA) and the prevalence studies published from January 1991 to January 2018. Each article was cross-referenced with "Asia-Pacific region" and countries in this regionsuch as Australia, New Zealand, India, Pakistan, Turkey, Iran and others.Results: We included 66 studies, which reported the prevalence of GRDs in the Asia-Pacific region. Prevalence of celiac disease was 0.32%-1.41% in healthy children and 0.05%-1.22% in the adult population, while the prevalence in the high risk population was higher (0.6%-11.8%). Previous studies have shown a very low incidence of dermatitis herpetiformis (DH) (<0.001%) and gluten ataxia (GA) in this area. Few studies on NCGS outbreaks have been found in this area due to the lack of specific diagnostic biomarkers. Wheat allergy (WA), although uncommon in most Asian-Pacific countries, is the most common cause of anaphylaxis in this region.Conclusion: The results of this systematic review suggest the need to plan further proper epidemiological studies in order to understand the natural history of GRDs and to assess its burden on health systems

Up regulation of long non-coding RNAs BACE1 and down regulation of LINC-PINT are associated with CRC clinicopathological characteristics

Background Long non-coding RNAs (LncRNAs) are known to have regulatory consequences for aberrant gene expression in cancers. The aim of this study was to evaluate the expression levels of long non-encoding RNAs, BACE1 (β-secretase1) and LINC-PINT (Long Intergenic Non-Protein Coding RNA, P53 Induced Transcript), in colorectal cancer (CRC) with clinicopathological parameters. Methods and results Bioinformatics analysis defning efectual signalling pathways Wnt. A total of 130 tissue samples (50 fresh CRC tissues with parallel adjacent normal tissues (ADJ) accompanied with 30 normal healthy control tissue samples) were collected from the Iranian population. mRNA expression analysis was performed via Real Time Q-PCR. Statistical analysis for comparing CRC expression levels with ADJ and normal healthy tissues were carried out using Kruskal–Wallis tests. The Receiver Operating Characteristic (ROC) curve was plotted for each LNC, separately. We discovered that PINT and BACE1 expression levels were decreased and increased respectively in CRC tumour samples compared with ADJ normal and healthy tissues. Clinicopathological parameter assessment revealed a signifcant relationship between PINT expression, tumour location, staging and distant metastasis (p<0.009, p<0.014, p<0.008, respectively). Also, BACE1 over expression was signifcantly associated with tumour site (p<0.009), metastasis (p<0.017) and histological diferentiation (p<0.028) and staging (p<0.017). Furthermore, ROC curve plotting showed LINC-PINT LNC-BACE1 may distinguish between early and late-stage of CRC, highlighting the value of both BACE1 and PINT as CRC progression biomarkers. Conclusion We investigated two LNCRNAs (PINT and BACE1) as potential CRC prognostic biomarkers, which are imperative for early and efective medical intervention in CRC. Expression levels of PINT and BACE1 in CRC tissue samples may serve to identify metastasis earlier, increasing patient survival rates and expediating clinical treatment options

Urinary 8-Hydroxy-Deoxyguanosine as a Biomarker of Oxidative DNA Damage in Employees of Subway System

Exposure to air pollutants, steel dust or other occupational and environmental hazards as oxidative stress have adverse effects on subway workers' health. Oxidative stress generates an excessive amount of reactive oxygen species (ROS) and Oxygen Free Radicals during their work time in the tunnels. Once DNA is repaired, Urinary 8-hydroxy-deoxyguanosine (8-OHdG) is excreted in the urine. Therefore, urinary level of 8-OHdG can reflect the extent of oxidative DNA damage. The aim of this study was to document the oxidative stress caused by exposure to these hazards by measuring 8-OHdG in workers urine. We collected urine samples of 81 male subway workers after their working shift. The concentration of urinary 8-OHdG was measured by ELISA method. We used linear regression analysis to compare the level of urinary 8-OHdG as a biomarker of oxidative stress between workers in tunnels and other staff. The mean concentration of urinary 8-OHdG for workers in the tunnel was 58.05 (SD=28.83) ng/mg creatinine and for another staff was 54.16 (SD =26.98) ng/mg creatinine.  After adjustment for age, smoking, driving and a second job in a linear regression model, the concentration of 8-OHdG for the exposed group was significantly higher than unexposed group (P=0.038). These findings confirm that the concentration of urinary 8-OHdG for workers who work in tunnels was significantly higher than the other staff. Additional investigations should be performed to understand that which ones of occupational exposures are more important to cause oxidative stress

Silica nanoparticles permeabilize lipid bilayers

Potential toxic effects of synthetic nanoparticles are of great public concern. Presently, the impact of nanoparticles at a cellular level is assessed by adding nanoparticles to cell cultures and subsequent evaluation of particle uptake by confocal fluorescence microscopy and of cell viability by conventional (fluorescence) assays. Cytotoxic effects of nanoparticles have been reported but a correlation between nanoparticle properties (e.g. size, shape, surface chemistry) and cell viability remains elusive. However, cellular uptake of nanoparticles is almost universally observed. Membrane translocation of nanoparticles is generally considered to be an active process, requiring the presence of receptors that mediate encapsulation of the nanoparticles into an intracellular vesicle, from which the particles may or may not escape into the cytosol. Using electrophysiological methods we have demonstrated that spherical silica nanoparticles, under development for intracellular drug delivery, are able to permeabilize protein-free lipid bilayers as a function of size and surface charge. Single channel-like conductances, similar to those induced by membrane-disrupting ?-amyloid peptides, are observed for rigid sterol-containing bilayers. For more fluid bilayers of DOPC the conductance gradually increases until the bilayer disintegrates, which has also been observed for cytotoxic amyloid oligomers. The most disruptive nanospheres were shown by confocal fluorescence microscopy to accumulate at the bilayer surface, and we demonstrated that a fraction of these particles translocate across the lipid bilayer, suggesting that passive uptake of nanoparticles may contribute to cellular uptake. Our combined electrophysiology and fluorescence microscopy approach is experimentally straightforward and enables rapid systematic investigation of the interactions between nanoparticles and the lipid components of the cell membrane. These model studies will aid in the rational design of safe nanoparticles -for drug delivery and subcellular labeling- that traverse the plasma membrane without adverse effects on membrane integrity

Prevalence of Low Back Pain in Health Care Workers and Comparison with other Occupational Categories in Iran: A Systematic Review

Background: There are few research studies evaluating the significance of low back pain (LBP) in Iran, even though the majority of locally published surveys are written in the Persian language. In the present review study, we aimed at appraising published articles related to the burden of LBP and its divergence among different jobs. Methods: A comprehensive search was conducted in all accessible national and international electronic databases from 1948 to mid-2012. The international electronic databases were MEDLINE (PubMed), Web of Sciences, Google Scholar, Scopus, CINAHL, and the Iranian equivalents were SID, IRANDOC, IranMedex, and Magiran. The main search terms were musculoskeletal disorders, musculoskeletal symptoms, low back pain, back pain, and Iran. All keywords were searched electronically by three Boolean operators. The inclusion criteria were age ≥10 years, study focus on LBP prevalence, inclusion of both genders, and no limitation to the study design. A dedicated STROBE questionnaire was developed as a critical appraisal tool and the quality of the identified literature was examined according to the 5-point Linker scale. Articles scoring ≥3 on the Linker scale were appraised. Each literature was screened by four reviewers independently and possible disagreements were streamlined in a joint review meeting. The extracted data were entered into a dedicated table using Microsoft Office Excel program. Data were analyzed for homogeneity using the STATA software (version 11). Results: Of the 51 articles that were included in the present review study, 35 articles reported 1-year LBP with Nordic questionnaire and 3 articles reported point prevalence of LBP. The calculated global prevalence of 1-year LBP in workers was 25% and LBP was the most prevalent issue among health care workers. There was no association between the prevalence of LBP and job classification among workers. Conclusion: LBP is the most common issue among health care workers. It is recommended that future research should focus on this job category for investigating LBP prevalence. This allows parameters that increase the frequency of LBP to be assessed and subsequently permits the reduction or elimination of such factors