Showing papers by "Rama Shanker Verma published in 2009"

Humanized immunotoxins: A new generation of immunotoxins for targeted cancer therapy

Abstract: Chemotherapy, radiation, and surgery are the conventional treatment modalities for cancer. The success achieved with these approaches has been limited due to several factors like chemoresistance to drugs, non-specificity leading to peripheral toxicity, and non-resectable tumors. To combat these problems, the concept of targeted therapy using immunotoxins was developed. Immunotoxins are chimeric proteins with a cell-selective ligand chemically linked or genetically fused to a toxin moiety and can target cancer cells overexpressing tumor-associated antigens, membrane receptors, or carbohydrate antigens. Ligands for these receptors or monoclonal antibodies or single chain variable fragments directed against these antigens are fused with bacterial or plant toxins and are made use of as immunotoxins. Pseudomonas exotoxin, anthrax toxin, and diphtheria toxin are the commonly used bacterial toxins. Ricin, saporin, gelonin, and poke weed antiviral protein are the plant toxins utilized in immunotoxin constructs. Several such fusion proteins are in clinical trials, and denileukin difitox is a FDA-approved fusion protein. In spite of the promise shown by bacterial- and plant toxin-based chimeric proteins, their clinical application is hampered by several factors like immunogenicity of the toxin moiety and non-specific toxicity leading to vascular leak syndrome. In order to overcome these problems, a novel generation of immunotoxins in which the cytotoxic moiety is an endogenous protein of human origin like proapoptotic protein or RNase has been developed. This review summarizes the advances in this new class of fusion protein and the future directions to be explored.

Molecular Analysis of Coagulase Gene Polymorphism in Clinical Isolates of Methicilin Resistant Staphylococcus aureus by Restriction Fragment Length Polymorphism Based Genotyping

Abstract: Problem statement: To investigate coagulase gene variants through Res triction Fragment Length Polymorphism (RFLP) amongst clinical isolates of Methicillin-Resistant Staphylococcus Aureus (MRSA) collected from Chennai based hospitals. Approach: A total of 85 MRSA clinical isolates collected from various clinical sources were studie d for the molecular typing purpose. To perform coagulase gene typing, the repeated units encoding hypervariable regions of the Staphylococcus aureus coagulase gene were amplified by the PCR followed by AluI and HaeIII restriction enzyme digestion of the PCR product and analyzed for RFLP. Results: Cluster analysis performed with Un-weighted Pair Grouping Using Arithmetic Mean Analysis (UPGMA) at >80% similarity level classified all strains into 31 and 21 genotypes based upon AluI an d HaeIII RFLP patterns respectively. AluI RFLP patterns gave a high discriminatory index and prove d to be better than that of HaeIII in typing of MRSA strains. Conclusion: Method investigated in this study, proved to be qu ick, reliable and useful for typing large number of MRSA strains from various clinical isolates with high fidelity. Grouping of strains based on RFLP patterns of both enzymes, improved the discriminatory index. Finally, using this methodology group of epidemiological strains can be typed reliably and effectively using both enzymes. Significance and impact of the study: This efficient and reliable typing procedure is beneficial to develop efficient infection control m easures in hospitals for staphylococcal infection. This typing procedure could be used to analyze large number of strains with in a short period of time and thus useful for epidemiological investigations.

Use of Electronic Information Resources: A Case Study of Thapar University

Abstract: This paper is an attempt to study the issues like use of electronic information resources, its impact on the collection of print and electronic journals its awareness among the users, and the places where the users are accessing these resources. A survey was conducted in the academic year 2006-07 at the Thapar University, Patiala. A total number of 504 users from the undergraduate, postgraduate, research scholar and faculty members were selected and their response was obtained with the help of questionnaire. The findings show that users from all these categories were using e-resources; the awareness about e-resources encourages users to use such resources to the maximum; and the users are using computer centre and hostels more for accessing the information. The impact of e-resources was visible from the decrease in number of printed journals in comparison to the increase in number of electronic journals. The use of e-journals has increased manifold. The printed material is being quickly replaced by the electronic resources. http://dx.doi.org/10.14429/djlit.29.243

Use and impact of electronic journals in the Indian Institute of Technology, Delhi, India

Abstract: Purpose – This paper aims to describe the use of electronic resources and services provided at the central library of Indian Institute of Technology, Delhi. The paper is focused to know who these electronic information services users are, how often they use the services and the place where the information is accessed. Also, the users are asked to give their preferences between an electronic and print journal format.Design/methodology/approach – The questionnaire method is used for collecting the data from the users (i.e. undergraduate, postgraduate, research scholar and faculty), categories‐wise.Findings – It has been found that usage of e‐journals is increasing; this is due to awareness among the users about the library e‐resources and services. Owing to an easy access available at various places in the institute, users are accessing these resources at hostels and departments more as compared to the library. The users coming to library have decreased.Originality/value – The present paper will help other ...

Antibacterial and antioxidant activity of methanol extract of Evolvulus nummularius.

Abstract: Objective : To evaluate the antibacterial and antioxidant activity of methanol extract of Evolvulus nummularius (L) L. Materials and Methods : Disc diffusion and broth serial dilution tests were used to determine the antibacterial activity of the methanol extract against two Gram-positive bacterial strains (Bacillus subtilus NCIM 2718, Staphylococcus aureus ATCC 25923) and three Gram-negative bacterial strains (Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 70063 and Escherichia coli ATCC 25922). The methanol extract was subjected to preliminary phytochemical analysis. Free radical scavenging activity of the methanol extract at different concentrations was determined with 2, 2-diphenyl-1picrylhydrazyl (DPPH). Results : The susceptible organisms to the methanol extract were Escherichia coli (MIC=12.50 mg/ml) and Bacillus subtilus (MIC=3.125 mg/ml) and the most resistant strains were Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. The methanol extracts exhibited radical scavenging activity with IC50 of 350 μg/ml. Conclusion : The results from the study show that methanol extract of E.nummularius has antibacterial activity. The antioxidant activity may be attributed to the presence of tannins, flavonoids and triterpenoids in the methanol extract. The antibacterial and antioxidant activity exhibited by the methanol extract can be corroborated to the usage of this plant in Indian folk medicine.

Tumor cell imaging using the intrinsic emission from PAMAM dendrimer: a case study with HeLa cells

Abstract: HeLa 229 cells were treated with methotrexate (MTX) and doxorubicin (DOX), utilizing fourth generation (G4), amine terminated poly(amidoamine) {PAMAM} dendrimer as the drug carrier. In vitro kinetic studies of the release of both MTX and DOX in presence and absence of G4, amine terminated PAMAM dendrimers suggest that controlled drug release can be achieved in presence of the dendrimers. The cytotoxicity studies indicated improved cell death by dendrimer-drug combination, compared to the control experiments with dendrimer or drug alone at identical experimental conditions. Furthermore, HeLa 229 cells were imaged for the first time utilizing the intrinsic emission from the PAMAM dendrimers and drugs, without incorporating any conventional fluorophores. Experimental results collectively suggest that the decreased rate of drug efflux in presence of relatively large sized PAMAM dendrimers generates high local concentration of the dendrimer-drug combination inside the cell, which renders an easy way to image cell lines utilizing the intrinsic emission properties of PAMAM dendrimer and encapsulated drug molecule.

A multiplex PCR technique to characterize human bone marrow derived mesenchymal stem cells.

Abstract: Human mesenchymal stem cells (MSCs), with capacity to differentiate into adipocytes, osteoblasts and chondrocytes, offer potential for the development of novel treatments. A critical question in MSCs biology is whether this cell population possesses a relatively uniform differentiation capability or is comprised of distinct subsets of progenitors committed to differentiate in particular pathways. To quantify the changes during growth of MSCs, we analyzed the mesenchymal phenotype and differentiation ability using a multi-marker PCR with six primer sets specific for CD73, CD90, CD105, CD166, CD45 and β-actin allowing a gel-based differential detection of the PCR products. To determine degree of variability of MSCs populations in terms of proliferation, cell proliferation assays were performed on expanded MSCs up to the sixth passage. At each passage, the osteogenic and adipogenic differentiation potentials of MSCs were verified by culture in inductive media. RT-PCR and cytochemical analysis revealed that, despite the loss of multipotentiality during expansion, certain markers remain expressed, indicating that these markers are unlikely to be reflective of the MSC’s true ‘stem cell’ nature. Our results suggest that decrease in the expression of MSCs specific markers correlates with down-regulation of proliferation ability and differentiation efficiency of MSCs.

Differential Usage of the Transport Systems for Folic acid and Methotrexate in Normal Human T-Lymphocytes and Leukemic Cells

Abstract: Methotrexate (MTX) has been used as an effective anti-cancer drug for a long time. Conceptually, it is accepted that MTX and folic acid are transported by folate receptors (FRs) in cancerous cells, but the exact mechanism of MTX uptake in human leukemia is unknown. The objective of this study was to investigate different transport systems for FA and MTX, and to delineate their uptake mechanism in MOLT4, K562, Hut78 leukemia cells and normal human T cells. In MOLT4, uptake of MTX was higher than FA, similar to that of K562, Hut78 and normal T cells. In MOLT4 cells, MTX uptake was maximum at pH 7.4 whereas FA uptake was maximum at pH 4.5. Uptake of FA and MTX was significantly inhibited by anions, suggesting anion-dependent transport system. FA uptake was found to be energy dependent whereas MTX uptake was energy independent. RT-PCR and immunofluorescence results demonstrated the presence of reduced folate carrier as well as proton coupled folate transporter and absence of FR in MOLT4 and normal T cells. These data suggest the existence of two separate and independent carrier-mediated transport systems for the uptake of FA and MTX in normal and leukemic human T cells.

Nanobiotechnology: Application of Nanotechnology in Therapeutics and Diagnosis

Abstract: Nanobiotechnology is a recently coined term describing the convergence of the two existing but distant worlds of engineering and molecular biology. Nanobiotechnology is the interface between nanotechnology and biology. This is a combination of three words: NANO is tiny, BIO is living things, and TECHNOLOGY is about tools. It is an emerging area of scientific and technological advancement. Nanobiotechnology refers to the ability to create and manipulate biological and biochemical materials, devices, and systems at atomic and molecular levels (billionth of a meter). Thus, it is an integration of physical sciences, molecular engineering, biology, chemistry, and biotechnology, and holds considerable promise of advances in pharmaceuticals and health care. Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior, indispensable in many areas of human activity, and above all a tiny tool to learn about liv...