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Search Results: 1 - 10 of 79 matches for " Roopa Hebbandi Nanjundappa "
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CD154 and IL-2 Signaling of CD4+ T Cells Play a Critical Role in Multiple Phases of CD8+ CTL Responses Following Adenovirus Vaccination
Channakeshava Sokke Umeshappa, Roopa Hebbandi Nanjundappa, Yufeng Xie, Andrew Freywald, Yulin Deng, Hong Ma, Jim Xiang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0047004
Abstract: Adenoviral (AdV) vectors represent most commonly utilized viral vaccines in clinical studies. While the role of CD8+ cytotoxic T lymphocyte (CTL) responses in mediating AdV-induced protection is well understood, the involvement of CD4+ T cell-provided signals in the development of functional CD8+ CTL responses remain unclear. To explore CD4+ T helper signals required for AdVova-stimulated CTL responses, we established an adoptive transfer system by transferring CD4+ T cells derived from various knock out and transgenic mice into wild-type and/or CD4-deficient animals, followed by immunizing with recombinant ovalbumin (OVA)-expressing AdVova vector. Without CD4+ T help, both primary and memory CTL responses were greatly reduced in this model, and were associated with increased PD-1 expression. The provision of OVA-specific CD4+ T help in CD4+ T cell-deficient mice restored AdVova-induced primary CTL responses, and supported survival and recall responses of AdVova-stimulated memory CTLs. These effects were specifically mediated by CD4+ T cell-produced IL-2 and CD154 signals. Adoptive transfer of “helped” or “unhelped” effector and memory CTLs into na?ve CD4+ T cell-deficient or -sufficient mice also revealed an additional role for polyclonal CD4+ T cell environment in the survival of AdVova-stimulated CTLs, partially explaining the extension of CTL contraction phase. Finally, during recall responses, CD4+ T cell environment, particularly involving memory CD4+ T cells, greatly enhanced expansion of memory CTLs. Collectively, our data strongly suggest a critical role for CD4+ T help in multiple phases of AdV-stimulated CTL responses, and could partially explain certain failures in AdV-based immunization trials targeting malignant tumors and chronic diseases that are often associated with compromised CD4+ T cell population and function.
Th Cells Promote CTL Survival and Memory via Acquired pMHC-I and Endogenous IL-2 and CD40L Signaling and by Modulating Apoptosis-Controlling Pathways
Channakeshava Sokke Umeshappa, Yufeng Xie, Shulin Xu, Roopa Hebbandi Nanjundappa, Andrew Freywald, Yulin Deng, Hong Ma, Jim Xiang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064787
Abstract: Involvement of CD4+ helper T (Th) cells is crucial for CD8+ cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4+ Th’s signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4+ Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4+ T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2Kb/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4+ Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4+ Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4+ Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.
The Onset of Ferromagnetic Convection in a Micropolar Ferromagnetic Fluid Layer Heated from Below  [PDF]
C. E. Nanjundappa, I. S. Shivakumara, K. Srikumar
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2013, DOI: 10.4236/jemaa.2013.53020

The onset of ferromagnetic convection in a micropolar ferromagnetic fluid layer heated from below in the presence of a uniform applied vertical magnetic field has been investigated. The rigid-isothermal boundaries of the fluid layer are considered to be either paramagnetic or ferromagnetic and the eigenvalue problem is solved numerically using the Galerkin method. It is noted that the paramagnetic boundaries with large magnetic susceptibility χ delays the onset of ferromagnetic convection the most when compared to very low magnetic susceptibility as well as ferromagnetic boundaries. Increase in the value of magnetic parameter M1 and spin diffusion (couple stress) parameter N3 is to hasten, while increase in the value of coupling parameter N1 and micropolar heat conduction parameter N5 is to delay the onset of ferromagnetic convection. Further, increase in the value of M1, N1, N5 and χ as well as decrease in N3 is to diminish the size of convection cells.

Penetrative Bénard-Marangoni Convection in a Micropolar Ferrofluid Layer via Internal Heating and Submitted to a Robin Thermal Boundary Conditions  [PDF]
H. Nagarathnamma, A. Pavithra, C. E. Nanjundappa, S. P. Suma
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2018, DOI: 10.4236/jemaa.2018.105007
Abstract: Penetrative Bénard-Maranagoni convection in micropolar ferromagnetic fluid layer in the presence of a uniform vertical magnetic field has been investigated via internal heating model. The lower boundary is considered to be rigid at constant temperature, while the upper boundary free open to the atmosphere is flat and subject to a convective surface boundary condition. The resulting eigenvalue problem is solved numerically by Galerkin method. The stability of the system is found to be dependent on the dimensionless internal heat source strength Ns, magnetic parameter M1, the non-linearity of magnetization parameter M3, coupling parameter N1, spin diffusion parameter N3 and micropolar heat conduction parameter N5. The results show that the onset of ferroconvection is delayed with an increase in N1 and N5 but hastens the onset of ferroconvection with an increase in M1, M3, N3 and Ns. The dimension of ferroconvection cells increases when there is an increase in M3, N1, N5 and Ns and decrease in M1 and N3.
Stem cell therapy - Hype or hope? A review
Nadig Roopa
Journal of Conservative Dentistry , 2009,
Abstract: While the regeneration of a lost tissue is known to mankind for several years, it is only in the recent past that research on regenerative medicine/dentistry has gained momentum and eluded the dramatic yet scientific advancements in the field of molecular biology. The growing understanding of biological concepts in the regeneration of oral/dental tissues coupled with experiments on stem cells is likely to result in a paradigm shift in the therapeutic armamentarium of dental and oral diseases culminating in an intense search for "biological solutions to biological problems." Stem cells have been successfully isolated from variety of human tissues including orofacial tissues. Initial evidence from pioneering studies has documented the likely breakthrough that stem cells offer for various life-threatening diseases that have so far defeated modern medical care. The evidence gathered so far has propelled many elegant studies exploring the role of stem cells and their manifold dental applications. This review takes you on a sojourn of the origin of stem cells, their properties, characteristics, current research, and their potential applications. It also focuses on the various challenges and barriers that we have to surmount before translating laboratory results to successful clinical applications heralding the dawn of regenerative dentistry.
Study of Surface Instability of Kelvin-Helmholtz Type in a Fluid Layer Bounded above by a Porous Layer and below by a Rigid Surface  [PDF]
Nanjundappa Rudraiah, Krishna Basappa Chavaraddi, Inapura Siddagangaiah Shivakumara, Bangalore Mahadevaiah Shankar
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.16033
Abstract: The surface instability of Kelvin-Helmholtz type bounded above by a porous layer and below by a rigid surface is investigated using linear stability analysis. Here we adopt the theory based on electrohydrodynamic as well as Stokes and lubrication approximations. We replace the effect of boundary layer with Beavers and Joseph slip condition. Here we have studied the combined effect of electric and magnetic fields on Kelvin-Helmholtz instability (KHI) in a fluid layer bounded above by a porous layer and below by a rigid surface. The dispersion relation is obtained using suitable boundary and surface conditions and results are depicted graphically. Also the ratio Gm is numerically computed for different values of We and M given in the Table 1. From this it is clear that the combined effect of electric and magnetic fields with porous layer are more effective than the effect of compressibility in reducing the growth rate of RTI. Also, these results shows that with a proper choice of magnetic field it is possible to control the growth rate of Electrohydrody-namic KHI (EKHI) and hence can be restored the symmetry of IFE target.
A High Performance Binary Data Compression Technique Using Low Puncturing Turbo Codes
Chitra M,Roopa M
International Journal of Engineering and Advanced Technology , 2012,
Abstract: In this paper, we present a distributed coding technique for binary data compression. The performance of the proposed architecture is higher when compared with the existing techniques. The complexity of the traditional encoder is distributed to the decoder. Thus the proposed architecture can be used for the applications where the complexity of decoder can be more than that of an encoder.
Antiretrovirals: Need for an effective drug delivery
Devi Kusum,Pai Roopa
Indian Journal of Pharmaceutical Sciences , 2006,
Abstract: Human Immunodeficiency Virus (HIV) is a retrovirus that causes irreversible destruction of the immune system, leading to the occurrence of opportunistic infections and malignancies. During the last decade, even though attempts were being made to eradicate HIV, it was found that eradication of HIV is highly unlikely, and effective antiretroviral therapy is required on a long-term basis to maintain viral suppression and reduce disease progression. During this decade, effective therapies aimed at continued suppression of HIV replication and targeted at resting HIV reservoirs such as brain, lymphatic systems will be critical to prolong survival and renewing hopes for a cure. Currently available antiHIV drugs can be classified into three categories: nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors. Most of these drugs bear some significant drawbacks such as relatively short half-life, low bioavailability, poor permeability and undesirable side effects. Efforts have been made to design drug delivery systems for antiHIV agents to: a) reduce the dosing frequency, b) increase the bioavailability and decrease the degradation/metabolism in the gastrointestinal tract, c) improve the CNS penetration and inhibit the CNS efflux, and d) deliver them to the target cells selectively with minimal side effects. This article is an attempt to compile all major research work towards drug delivery for AIDS therapy and channel future attempts in the area of more effective controlled delivery of antiHIV agents.
Evaluation of a modified team based learning method for teaching general embryology to 1 st year medical graduate students
Shankar Nachiket,Roopa R
Indian Journal of Medical Sciences , 2009,
Abstract: Background and Aims: To encourage student participation in the learning process, the authors introduced a modified team based learning (TBL) method to cover two general embryology topics in the 1 st year MBBS curriculum. The aim of this study was to evaluate students′ perception of this method vis-à-vis the lecture method of teaching. Settings and Design: A questionnaire was used to survey and evaluate the perceptions of 1 st year MBBS students at the Department of Anatomy at our medical college in India. Materials and Methods: A total of eight classes were allotted to cover General Embryology. Six of these classes were conducted using the traditional didactic lecture method. Two topics were covered using the modified TBL method. Five teams of students were constituted, and each team was given handouts which contained basic factual material, four clinical case histories, and previous university exam questions from the topic. On the day of the session, these were discussed in the presence of the faculty facilitator. Students evaluated these sessions through a questionnaire. Results: A majority of students felt that the modified TBL sessions were better at fulfilling learning objectives (46 students, 85%), enabled better understanding (43 students, 79%), were more interesting (43 students, 81%), ensured greater student participation (51 students, 94%) and involved greater effort on the part of students (53 students, 98%), as compared to traditional teaching methods. Most of the students (43 students, 79%) opined that more such sessions should be organized in the future. Conclusions: Responses from students show that the modified TBL classes could be utilized judiciously along with the traditional didactic lectures for teaching embryology.
Unusual bilateral origins of the deep artery of thigh and associated variations
Shankar N,Roopa R
International Journal of Anatomical Variations , 2009,
Abstract: During routine dissection of a middle aged male cadaver, an unusual origin of the deep artery of thigh was observed bilaterally. It arose from the femoral artery less than 1 cm distal to the inguinal ligament. On both sides, its diameter was greater than that of the femoral artery. An unusually distal origin of the lateral circumflex femoral artery was observed bilaterally. An unnamed branch from the deep artery of thigh on the left side was seen coursing superolaterally towards the anterior superior iliac spine. The deep external pudendal artery arose from the medial circumflex femoral artery on either side. On the right side, the femoral nerve emerged in the femoral triangle by piercing the iliacus muscle. As the deep artery of thigh is often used in vascular reconstructive procedures and is frequently visualized by various radiological imaging techniques, anatomical variations of itself as well as its branches have significant clinical implications.
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