Amar Bahadur Singh

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Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength,(More)
Disruption of the cell-cell junction with concomitant changes in the expression of junctional proteins is a hallmark of cancer cell invasion and metastasis. The role of adherent junction proteins has been studied extensively in cancer, but the roles of tight junction (TJ) proteins are less well understood. Claudins are recently identified members of the(More)
The serine/threonine kinase Akt/protein kinase B and the pleiotropic transcription factor nuclear factor-kappaB [NF-kappaB (p50/p65)] play important roles in the control of cell proliferation, apoptosis, and oncogenesis. Previous studies from our laboratory have shown the constitutive activation of NF-kappaB in melanoma cells. However, the mechanism of this(More)
Tight junctions (TJs) are the most apical cell-cell junctions, and claudins, the recently identified TJ proteins, are critical for maintaining cell-cell adhesion in epithelial cell sheets. Based on their in vivo distribution and the results of overexpression studies, certain claudins, including claudin-1 and -4, are postulated to increase, whereas other(More)
Mammalian kidney expresses all of the members of the ErbB family of receptors and their respective ligands. Studies support a role for ErbB family receptor activation in kidney development and differentiation. Under physiologic conditions, EGFR activation appears to play an important role in the regulation of renal hemodynamics and electrolyte handling by(More)
We present evidence that the neurite out-growth stimulated by the binding of Thy-1 antibodies to PC12 cells is mediated by calcium influx through both N- and L-type calcium channels. PC12 cells cultured on a noncellular substratum in the presence of NGF, or on a cellular substratum in the absence of NGF, responded to soluble Thy-1 antibody by extending(More)
Tight junctions are the apical cell-cell adhesion that regulate paracellular permeability and are critical for epithelial cell polarity. Molecular architecture of tight junction has been studied extensively, which has confirmed that claudin family of proteins is integral component of tight junction. Loss of cell-cell adhesion is central to the cellular(More)
In the present study, we demonstrate that rat kidney contains caspase activity that was markedly inhibited by specific peptide inhibitors of caspases but not by inhibitors of Ser, Cys, Asp, or metalloproteinases. Using primers based on the nucleotide sequence of known members of Ced-3/interleukin-1 beta-converting enzyme (ICE) family from human origin, we(More)
BACKGROUND Overexpression of programmed death 1 (PD-1) receptor is thought to inhibit the effector T-cell response in human tuberculosis. However, the precise mechanism of such inhibition remains unclear. The present study addresses the role of PD-1 in dampening host T-cell function among patients with pulmonary tuberculosis. METHODS Expression of PD-1(More)
Claudin-2 is a unique member of the claudin family of transmembrane proteins, as its expression is restricted to the leaky epithelium in vivo and correlates with epithelial leakiness in vitro. However, recent evidence suggests potential functions of claudin-2 that are relevant to neoplastic transformation and growth. In accordance, here we report, on the(More)