Publications by authors named "Sujatha Radhakrishnan"

Dementia is a condition in which cognitive ability deteriorates beyond what can be anticipated with natural ageing. Characteristically it is recurring and deteriorates gradually with time affecting a person's ability to remember, think logically, to move about, to learn, and to speak just to name a few. A decline in a person's ability to control emotions or to be social can result in demotivation which can severely affect the brain's ability to perform optimally.

View Article and Find Full Text PDF

MicroRNA-mediated regulation of gene expression appears to be involved in a variety of cellular processes, including development, differentiation, proliferation, and apoptosis. Mir-146a is thought to be involved in the regulation of the innate immune response, and its expression is increased in tissues associated with chronic inflammation. Among the predicted gene targets for mir-146a, the chemokine CCL8/MCP-2 is a ligand for the CCR5 chemokine receptor and a potent inhibitor of CD4/CCR5-mediated HIV-1 entry and replication.

View Article and Find Full Text PDF

BAG3, a member of the BAG co-chaperones family, is expressed in several cell types subjected to stressful conditions, such as exposure to high temperature, heavy metals, drugs. Furthermore, it is constitutively expressed in some tumors. Among the biological activities of the protein, there is apoptosis downmodulation; this appears to be exerted through BAG3 interaction with the heat shock protein (Hsp) 70, that influences cell apoptosis at several levels.

View Article and Find Full Text PDF

Progressive multifocal leukoencephalopathy (PML) is a fatal demyelinating disease of the central nervous system resulting from the productive infection of oligodendrocytes by the opportunistic polyomavirus JC virus (JCV). Apoptosis is a host defense mechanism to dispose of damaged cells; however, certain viruses have the ability to deregulate apoptotic pathways to complete their life cycles. One such pathway involves survivin, a member of the inhibitor of apoptosis family, which is abundantly expressed during development in proliferating tissues but should be absent in normal, terminally differentiated cells.

View Article and Find Full Text PDF

Progressive multifocal leukoencephalopathy (PML) is a fatal demyelinating disorder of the CNS caused by infection of glial cells with the polyomavirus, JCV. Here we report that genomic stability and DNA repair are significantly dysregulated by JCV infection of human astrocytes. Metaphase spreads exhibited increased ploidy correlating with duration of infection.

View Article and Find Full Text PDF

The human polyomavirus JC virus (JCV) is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), which is commonly seen in AIDS patients. The bicistronic viral RNA, which is transcribed at the late phase of infection, is responsible for expressing the viral capsid proteins and a small regulatory protein, agnoprotein. Immunohistochemical analysis of brain tissue from subjects with AIDS/PML revealed colocalization of the human immunodeficiency virus type 1 (HIV-1) transactivator, Tat, and JCV agnoprotein in nucleus and cytoplasm of "bizarre" astrocytes.

View Article and Find Full Text PDF

A synthetic cell binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was compared to open flap debridement (DEBR) in human periodontal osseous defects. Following initial preparation procedures, two osseous defects per patient were treated randomly with one of the two procedures after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 months clinical and radiographic assessments for soft tissue and hard tissue were performed for documentation and finalization of treatment.

View Article and Find Full Text PDF

The human polyomavirus, JC virus (JCV), encodes two regulatory proteins at the early (T antigen) and the late (agnoprotein) phases of viral infection whose activities are important for the production of the viral capsid proteins and the dysregulation of several host factors and their functions. For this study, we designed and utilized an RNA interference strategy via small interfering RNAs (siRNAs) that targeted the expression of T antigen and agnoprotein in human astrocytic cells. The treatment of cells with specific siRNA oligonucleotides targeting a conserved region of T antigen, nucleotides (nt) 4256 to 4276 (Mad-1 strain), caused a >50% decline in the level of T antigen and in its transcriptional activity upon the viral capsid genes as well as a significant reduction in viral DNA replication in infected cells.

View Article and Find Full Text PDF

Cell-type-specific transcription of the JC virus (JCV) promoter in glial cells initiates a series of events leading to viral replication in the brain and the development of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in patients with neurologic complications due to infection with human immunodeficiency virus type 1. Here we employed an in vitro infection of primary cultures of human astrocytes to compare the transcriptional profile of cellular genes after JCV infection by using an oligonucleotide-based microarray of 12600 genes. Transcription of nearly 355 genes was enhanced and expression of 130 genes was decreased to various degrees.

View Article and Find Full Text PDF

Background: GB virus C/hepatitis G virus (GBV-C/HGV) and TT virus (TTV) have been widely reported in patients with high parenteral risk such as haemodialysis and renal transplant recipients. The occurrence of these agents in association with hepatitis B virus (HBV) and hepatitis C virus (HCV), in Indian renal transplant recipients, is yet unreported.

Study Design: Molecular and serological markers of GBV-C/HGV and TTV were examined in addition to those for HBV, HCV and hepatitis D virus (HDV) in a selected group of seventy renal transplant recipients.

View Article and Find Full Text PDF

Background: Genotyping of the hepatitis C virus (HCV) and assessment of viral load is important for designing therapeutic strategies and region specific diagnostic assays.

Objectives: To determine the distribution of HCV genotypes among patients attending a tertiary care hospital in south India, and to correlate this with viral load.

Study Design: Ninety HCV RNA positive patients were recruited for the study.

View Article and Find Full Text PDF

Background: The association of GBV-C/HGV in patients at high risk of parenteral infection and those with chronic liver disease in southern India is unknown.

Objectives: To study the occurrence of GBV-C/HGV in three patient groups attending a tertiary care centre in Vellore and identify the prevailing genotype(s).

Study Design: Two hundred and twenty-seven individuals were studied using an RT-PCR assay with primers specific for the 5'NCR and the NS5a-coding regions.

View Article and Find Full Text PDF

The late region of the human neurotropic JC virus encodes a 71 amino acid protein, named Agnoprotein, whose biological function remains elusive. Here we demonstrate that in the absence of other viral proteins, expression of Agnoprotein can inhibit cell growth by deregulating cell progression through the cell cycle stages. Cells with constitutive expression of Agnoprotein were largely accumulated at the G2/M stage and that decline in the activity of cyclins A and B is observed in these cells.

View Article and Find Full Text PDF

Background: The human neurotropic polyomavirus, JCV, contains an open reading frame within the late region of the viral genome that encodes a 71-amino-acid protein, agnoprotein. Because accumulating evidence supports an association between JCV infection and human brain tumors, including medulloblastomas, we assessed the presence of JCV Agno gene sequences and the expression of agnoprotein in a series of 20 well-characterized medulloblastomas.

Methods: Formalin-fixed, paraffin-embedded tumor tissue samples were used for Agno gene amplification and for immunohistochemical analysis.

View Article and Find Full Text PDF