Archives of Advances in Biosciences

Micropipettes or piston pipettes are used to make most volume measurements in fields such as health, chemistry, biology, pharmacy and genetics. Laboratories must ensure that results obtained using these instruments are reliable; therefore, it is necessary to calibrate micropipettes. Before the start of the calibration process, we must check the precision of measurements. The objective of this work is to compare several methods for calculating the precision of three kinds of micropipettes according to the reference value in ISO 8655-6. The medical tests will not have accurate results, if the volume of the liquid doesn’t transfer precisely by micropipettes. Thus, the physician might potentially face problems in the disease diagnosis and its control. In the NCCLS EP5-A2, there is a method to specify and assess the precision of micropipettes by using CV (Coefficient of Variation). Also there are other methods to estimate and test the CV theory, in the formal statistics texts which could be applied to assess the micropipettes precision. In this research we evaluate the precision of lab micropipettes. Three brands of micropipettes, A, B and C are assigned to measure the distilled water mass by using accurate scale which is accurate up to 10^-6 to measure 50-gram weights. The experimental environment is a metrology lab which is approved by Iran Standard and Industrial Researches Organization. A technician sampled at the beginning of the experiment and then after 2 hours, the same technician repeated the sampling. Overall, each micropipette is used to measure 40 times with 10-repeat times for single measurement in 28 work days. Common statistical methods are used to estimate and test the CV. Point estimation of CV for micropipettes A, B and C were 0.50%, 0.64% and 1.56%, respectively. Furthermore, the upper limit of 95% confidence bounds for these three micropipettes using the exact method were 0.53%, 0.69% and 1.65%, respectively. Micropipette A met the ISO 8655-6 standard level, but micropipettes B and C did not. On average, measurement errors in micropipettes B and C were respectively 30% and 3.11 times more than micropipette A. By using the approach of CLS EP5-A2 and confidence interval for CV, precision of the three micropipettes were compared. Only one of them met the ISO 8655-6 standard level, but the others failed.

Since esophagus cancer is among the most fatal cancers all over the world and our country has the most frequent number of patients, identification of squamous cell carcinoma associated proteins would be essential. Finding molecular markers for recognition of the disease could be beneficial for efficient and early treatment of the disease. As protein expression in cancerous cells is different from normal ones, identification of protein expression pattern could be helpful for recognition of the disease. Proteomics is a novel method for recognition of protein collection in a specific tissue. In this method 2D gel electrophoresis is performed to separate all proteins, and then spot analysis will be done through mass spectrometry and bioinformatics software would help in the recognition of proteins. In comparison to normal tissue in cancerous cells, we would have up-regulation, down-regulation, appearance or disappearance of a specific protein. So, protein extraction was performed from healthy and cancerous mucosal tissue of esophagus and all peptides were separated through 2D gel electrophoresis. After spot analysis, proteins with different expression were identified with mass spectrometry and bioinformatics. In comparison to normal tissue, 14 proteins were found to over expressed or have no expression in tumors.  The main objective of this study is that proteomics is an ideal method to find the molecular basis of squamous cell carcinoma in esophageal cancer.

AITP mostly occur in children accompanied by variable clinical sings including petechiae, purpura, ecchymosis and severe bleeding. This study has determined and characterized the anti-platelet glycoproteins in children with ITP. The aim of this study was to determinate anti-platelet glycoproteins (GPs) using MAIPA method. During 18 months 38 children with clinical signs of AITP were studied in Mofid children hospital. To determine anti-platelet antibodies by ELISA technique, washed O negative platelets were used as a source of platelet antigens. MAIPA method was used to detect antibodies against individual platelet membrane glycoprotein. The anti-platelet antibodies level above mean+ 3SD of control group was assumed as positive. The results indicated that the platelet count ranges was between 2×109/L and 95×109/L. 63.5 % out of 38 patients were anti-platelet antibodies positive with ELISA method. The correlation between the above patients with anti-platelet antibody positive and clinical signs was 0.4. Results for determination of antibody against platelet GPIIb/IIIa, GPIb/IX and GPIa/IIa using MAIPA method were 44%, 51% and 25% respectively. In conclusion the preference of MAIPA method is the detection of very small amount of antibody. Since MAIPA is the specific method for the detection of antibody against glycoprotein antigens, it has the advantage of differentiating immune and non-immune thrombocytopenia.

A thin layer of poly methylen green (PMG) was covered on glassy carbon (GC) electrode surface by electrochemical polymerization method. In the next step by dropping a suspension of carboxylic acid functionalized carbon nano-tubes on the PMG/GC electrode a layer of CNTs was coated on the electrode. Thereafter, to immobilize the enzyme on electrode surface, three layers of PMG, alcohol dehydrogenase and PMG were added to the modified electrode, respectively. The Fourier transform infrared, scanning electron microscopy and cyclic voltammetry measurements clearly confirmed the successful immobilization of enzyme on the GC electrode.

Thermo-sensitive hydrogels were prepared by graft copolymerization of chitosan and N-Isopropylacrylamide via gamma radiation. Characterization of hydrogels such as ¹³C-NMR, DSC analysis and swelling test and cell assessments for harvesting living cell sheet were investigated. ¹³C-NMR and DSC analysis showed chitosan and NIPAAm monomer were grafted via gamma radiation successfully. Swelling ratio and curves results administrated hydrophilicity / hydrophobicity of hydrogel that this property is due to presence of PNIPAAm in different temperatures. The hydrogel was tested for harvesting epithelial cells after carrying out cell culture at 37 °C and incubating the confluent cells at 4°C for spontaneous detachment of cell sheet from hydrogel surface without enzyme treatment. Cell viability assay results and microscopic observations demonstrated that cells could attach to the hydrogel surface and maintain high viability and proliferation ability. Cell detachment efficiency from the hydrogel was high. These unique properties of the hydrogel would make it a promising support for epithelial cell grafting especially cornea regeneration.

Investigation of the web impact factor and analysis of the web links belong to webometric studies. A high impact factor, accompanied by more frequent links to a particular website, can indicate greater influence and better accessibility of that particular site. In this regard, bearing in mind the significance of medical universities' web sites for education and research, the current study compared and analyzed their impact factors, their web links and web pages, using AltaVista search engine. The investigation included different ranks of medical universities, commonly referred to as type 1, type 2 and type 3 universities in Iran. The median was used as a measure of central tendency of the scores. The search engines of AltaVista were adopted on 26 February 2010 to collect the data. According to the results, in terms of indexed pages, Shahid Baheshti of type 1, Guilan of type 2, and Shahrekord of type 3 universities had the best records. Regarding web links, medical universities of Iran, Kermanshah and Lorestan, from type 1, type 2 and type 3 universities had the best records and, in terms of impact factor, universities of Ahvaz (type 1), Zahedan (type 2), and Fessa (type 3) manifested the greatest influence. As the results imply, the universities are expected to pay more attention to webometric issues; they are also recommended to allocate more budget to enhance their web pages.

We analyzed in vitro expansion and differentiation of T progenitor cells from umbilical cord blood in the absence of thymic epithelium. The expansion setup is performed in the presence of SCF, IL-7 , and IL -2 with autologous serum .Using CBMCs as initial source , we compared the growth kinetics of several cell populations in either whole CBMC or  CD34+ -enriched-, as well as in CD3CD4CD8-depleted expansion assays by FACS analysis. After 11 days of culture, cell increase values were about 7 fold for CD3+, 6 fold for CD3+CD4+, 7 fold for CD3+CD8+, 4fold for CD3+CD56, 6fold for CD56+, and 0.2 fold for CD34+. We characterized the developmental state of these cell populations by RT –PCR analysis of the lymphoid differentiation markers RAG-1 and pre T-Alpha. In all samples , transcripts of both markers could be detected from day 0 though day 11, however , in case of pre – T-Alpha,  nested PCR  was always required , indicating lower expression . These findings; therefore, demonstrate that T-cell differentiation events (as opposed to mere expansion) do occur in stroma cell free expansion assays.

A balance between excitatory and inhibitory neurotransmissions in brain is an essential factor for the proper function of the brain. The amino acid gamma-aminobutyric-acid (GABA) is considered as the major inhibitory neurotransmitter in brain. Thus, GABAergic neurons play a key role in regulating behavior. Previous data have revealed the complex subunit structural design for GABA_A receptor channel, in which a pentameric assembly resulting from 5 of at least 21 subunits, grouped in the eight classes alpha (α1-6), beta (β1-4), gamma (γ1-4), delta, pi (π), epsilon (ε), theta (θ) and rho (ρ1-3) permits an immense number of putative receptor isoforms. GABA_ARs are highly diversed in the central nervous system in which this diversity may be related to some mental disorders. Any alteration in expression of the GABA_A receptor genes causes neurophysiological and functional consequences that might be associated with neurological disorders. Some neuropsychiatric disorders, such as anxiety, epilepsy and sleep disorders, are effectively treated with therapeutic agents that act on the GABA_A receptor. In this article, the contribution of GABA_A receptor deficits to central nervous system disorders, in particular anxiety disorders, epilepsy, schizophrenia and insomnia, will be reviewed. The better understanding of GABA and its receptors may help us to find novel therapeutic agents for treatment of mental disorder in future research.