Avicenna Journal of Medical Biotechnology
Year:2016 | Volume:8 | Issue:2|Papers Count:8

Alzheimer’s Disease (AD), the leading cause of dementia worldwide, is an irreversible progressive neurodegenerative disorder characterized by cognitive impairment and functional disability 1-3. Devastating nature of AD leads to serious social and economic impacts on the healthcare systems which implies the necessity of its proper management 1-3. It has been demonstrated that patients’ quality of life and their overall prognosis has a significant negative correlation with the severity of AD. Patients with severe AD need full-time care and assistance with some basic activities of daily living such as feeding and dressing in addition to severe deterioration in various domains of their cognitive functioning. Progress to a cure for AD has been hampered by the lack of information about the biology of the disease. The therapies currently approved for Alzheimer’s disease work by treating the patients’ symptoms, improving their cognitive and overall functions 4-8. Increasingly, however, experts are intent on slowing or halting the disease process, before it has ravaged patients’ brains. A lot of data is being generated on changes in imaging biomarkers before patients really become clinically significantly impaired. For example, there has been a lot of great work done in identifying patients early based on these biomarkers. The current therapeutic market is valued at $3 to $4 billion, shared among drugs that temporarily delay disease progression or address the symptoms but do not alter the underlying disease. Currently, medical biotechnology has brought new hopes in the treatment of Alzheimer's disease. For example one of the ongoing trials is related to bapineuzumab. Bapineuzumab is a monoclonal antibody (mAb) to target and clear b-amyloid. This vaccine is the first new drug aimed at slowing or even halting AD progression.

Diabetes Mellitus (DM) is a chronic heterogeneous disorder and oxidative stress is a key participant in the development and progression of it and its complications. Antioxidant status can affect vulnerability to oxidative damage, onset and progression of diabetes and diabetes complications. Superoxide dismutase 2 (SOD2) is one of the major antioxidant defense systems against free radicals. SOD2 is encoded by the nuclear SOD2 gene located on the human chromosome 6q25 and the Ala16Val polymorphism has been identified in exon 2 of the human SOD2 gene. Ala16Val (rs4880) is the most commonly studied SOD2 single nucleotide polymorphism (SNP) in SOD2 gene. This SNP changes the amino acid at position 16 from valine (Val) to alanine (Ala), which has been shown to cause a conformational change in the target sequence of manganese superoxide dismutase (MnSOD) and also affects MnSOD activity in mitochondria. Ala16Val SNP and changes in the activity of the SOD2 antioxidant enzyme have been associated with altered progression and risk of different diseases. Association of this SNP with diabetes and some of its complications have been studied in numerous studies. This review evaluated how rs4880, oxidative stress and antioxidant status are associated with diabetes and its complications although some aspects of this line still remain unclear.

Background: It seems that the success of vaccination for cancer immunotherapy such as Dendritic Cell (DC) based cancer vaccine is hindered through a powerful network of immune system suppressive elements in which regulatory T cell is the common factor. Foxp3 transcription factor is the most specific marker of regulatory T cells. In different studies, targeting an immune response against regulatory cells expressing Foxp3 and their removal have been assessed. As these previous studies could not efficiently conquer the suppressive effect of regulatory cells by their partial elimination, an attempt was made to search for constructing more effective vaccines against regulatory T cells by which to improve the effect of combined means of immunotherapy in cancer. In this study, a DNA vaccine and its respective protein were constructed in which Foxp3 fused to Fc(IgG) can be efficiently captured and processed by DC via receptor mediated endocytosis and presented to MHCII and I (cross priming).Methods: DNA construct containing fragment C (Fc) portion of IgG fused to Foxp3 was designed. DNA construct was transfected into HEK cells to investigate its expression through fluorescent microscopy and flow cytometry. Its specific expression was also assessed by western blot. For producing recombinant protein, FOXP3-Fc fusion construct was inserted into pET21a vector and consequently, Escherichia coli (E. coli) strain BL21 was selected as host cells. The expression of recombinant fusion protein was assayed by western blot analysis. Afterward, fusion protein was purified by SDS PAGE reverse staining.Results: The expression analysis of DNA construct by flow cytometry and fluorescent microscopy showed that this construct was successfully expressed in eukaryotic cells. Moreover, the Foxp3-Fc expression was confirmed by SDS-PAGE followed by western blot analysis. Additionally, the presence of fusion protein was shown by specific antibody after purification.Conclusion: Due to successful expression of Foxp3-Fc (IgG), it would be expected to develop vaccines in tumor therapies for removal of regulatory cells as a strategy for increasing the efficiency of other immunotherapy means.

Background: Traditional medicines with anti-diabetic effects are considered suitable supplements to treat diabetes. Among medicinal herbs, Stevia Rebaudiana Bertoni is famous for its sweet taste and beneficial effect in regulation of glucose. However, little is known about the exact mechanism of stevia in pancreatic tissue. Therefore, this study investigated the possible effects of stevia on pancreas in managing hyperglycemia seen in streptozotocin-induced Sprague-Dawley rats.Methods: Sprague-Dawley rats were divided into four groups including normo-glycemic, diabetic and two more diabetic groups in which, one was treated with aquatic extract of stevia (400 mg/kg) and the other with pioglitazone (10 mg/kg) for the period of 28 days. After completion of the experimental duration, rats were dissected; blood samples and pancreas were further used for detecting biochemical and histopathological changes. FBS, TG, cholestrol, HDL, LDL, ALT and AST levels were measured in sera. Moreover, MDA (malondialdehyde) level, catalase activity, levels of insulin and PPARg mRNA expression were also measured in pancreatic tissue.Results: Aquatic extract of stevia significantly reduced the FBS, triglycerides, MDA, ALT, AST levels and normalized catalase activity in treated rats compared with diabetic rats (p<0.05). In addition to this, stevia surprisingly, increased PPARg and insulin mRNA levels in treated rats (p<0.05). Furthermore, stevia compensated for the histopathological damage in diabetic rats.Conclusion: It is concluded that stevia acts on pancreatic tissue to elevate the insulin level and exerts beneficial anti-hyperglycemic effects through the PPARg-dependent mechanism and stevia’s antioxidant properties.

Background: Gold Nanoparticles (GNPs) are used in imaging and molecular diagnostic applications. As the development of a novel approach in the green synthesis of metal nanoparticles is of great importance and a necessity, a simple and safe method for the synthesis of GNPs using plant extracts of Zataria multiflora leaves was applied in this study and the results on GNPs’ anticancer activity against HeLa cells were reported.Methods: The GNPs were characterized by UV-visible spectroscopy, FTIR, TEM, DLS and Zeta-potential measurements. In addition, the cellular up-take of nanoparticles was investigated using Dark Field Microscopy (DFM). Induction of apoptosis by high dose of GNPs in HeLa cells was assessed by MTT assay, Acridin orange, DAPI staining, Annexin V/PI double-labeling flow cytometry and caspase activity assay.Results: UV-visible spectroscopy results showed a surface plasmon resonance band for GNPs at 530 nm. FTIR results demonstrated an interaction between plant extract and nanoparticles. TEM images revealed different shapes for GNPs and DLS results indicated that the GNPs range in size from 10 to 42 nm. The Zeta potential values of the synthesized GNPs were between 30 to 50 Mev, indicating the formation of stable particles. As evidenced by MTT assay, GNPs inhibit proliferation of HeLa cells in dose- dependent GNPs and cytotoxicity of GNPs in Bone Marrow Mesenchymal Stem Cell (BMSCs) was lower than cancerous cells. At nontoxic concentrations, the cellular up-take of the nanoparticles took place. Acridin orange and DAPI staining showed mor-phological changes in the cell’s nucleus due to apoptosis. Finally, caspase activity assay demonstrated HeLa cell’s apoptosis through caspase activation.Conclusion: The results showed that GNPs have the ability to induce apoptosis in HeLa cells.

Background: DNA isolation procedure can significantly influence the quantification of DNA by real time PCR specially when cell free DNA (cfDNA) is the subject. To assess the extraction efficiency, linearity of the extraction yield, presence of co-purified inhibitors and to avoid problems with fragment size relevant to cfDNA, development of appropriate External DNA Control (EDC) is challenging. Using non-human chimeric nucleotide sequences, an EDC was developed for standardization of qPCR for moni-toring stability of cfDNA concentration in blood samples over time.Methods: A DNA fragment of 167 bp chimeric sequence of parvovirus B19 and pBHA designated as EDC fragment was designed. To determine the impact of different factors during DNA extraction processing on quantification of cfDNA, blood samples were collected from normal subjects and divided into aliquots with and without specific treatment. In time intervals, the plasma samples were isolated. The amplicon of 167 bp EDC fragment in final concentration of 1.1 pg/ 500 ml was added to each plasma sample and total DNA was extracted by an in house method. Relative and absolute quantification real time PCR was performed to quantify both EDC fragment and cfDNA in extracted samples.Results: Comparison of real time PCR threshold cycle (Ct) for cfDNA fragment in tubes with and without specific treatment indicated a decrease in untreated tubes. In contrast, the threshold cycle was constant for EDC fragment in treated and untreated tubes, indicating the difference in Ct values of the cfDNA is because of specific treatments that were made on them.Conclusions: Spiking of DNA fragment size relevant to cfDNA into the plasma sample can be useful to minimize the bias due to sample preparation and extraction processing. Therefore, it is highly recommended that standard external DNA control be employed for the extraction and quantification of cfDNA for accurate data analysis.

Background: A simple and sensitive high performance liquid chromatography-elec-trospray ionization mass spectrometry method has been evaluated for the assignment of clonidine hydrochloride in human plasma.Methods: The mobile phase composed of acetonitrile-water 60:40 (v/v) and 0.2% for-mic acid 20 ml of sample was chromatographically analyzed using a repacked ZOR-BAX-XDB-ODS C18 column (2.1 mm´30 mm, 3.5m). Detection of analytes was achiev-ed by tandem mass spectrometry with Electrospray Ionization (ESI) interface in positive ion mode operated under the multiple-reaction monitoring mode (m/z 230.0 ®213). Sample pretreatment consisted of a one-step Protein Precipitation (PPT) with methanol and perchloric acid (HClO4) of 0.10 ml plasma.Results: Standard curve was linear (r=0.998) over the concentration range of 0.01-10.0 ng/ml and showed suitable accuracy and precision. The Limit of Quantification (LOQ) was 0.01 ng/ml. The mean (SD) Cmax, Tmax, AUCo-t and AUCo-¥ values after administration of the test and reference formulations, respectively, were in this manner: 6.16 (0.32) versus 6.21 (0.07) ng/ml, 30.12 (0.86) versus 30.13 (0.73) hr, 290.37 (1.13) versus 293.39 (1.22) ng/ml/hr, and 350.17 (1.98) versus 352.96 (1.67) ng/ml/hr. The mean (SD) t1/2 was 120.12 (1.90) hr for the test formulation and 120.96 (1.54) hr for the reference formulation. No statistical differences were showed for Cmax and the area under the plasma concentration-time curve for test and reference tablets.Conclusion: The method is rapid, simple, very steady and precise for the separation, assignment, pharmacokinetic and bioavailability evaluation of clonidine in healthy Iranian adult male volunteers.

Background: The pathogenesis of nontypeable Haemophilus influenzae (NTHi) begins with adhesion to the rhinopharyngeal mucosa. Almost 38-80% of NTHi clinical isolates produce proteins that belong to the High Molecular Weight (HMW) family of adhesins, which are believed to facilitate colonization.Methods: In the present study, the prevalence of hmwA, which encodes the HMW ad-hesin, was determined for a collection of 32 NTHi isolates. Restriction Fragment Length Polymorphism (RFLP) was performed to advance our understanding of hmwA binding sequence diversity.Results: The results demonstrated that hmwA was detected in 61% of NTHi isolates. According to RFLP, isolates were divided into three groups.Conclusion: Based on these observations, it is hypothesized that some strains of non-typeable Haemophilus influenzae infect some specific areas more than other parts.