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Gregory J Podgorski Mayank Bansal Nicholas S Flann 《Theoretical biology & medical modelling》2007,4(1):1-19
Background
A significant body of literature is devoted to modeling developmental mechanisms that create patterns within groups of initially equivalent embryonic cells. Although it is clear that these mechanisms do not function in isolation, the timing of and interactions between these mechanisms during embryogenesis is not well known. In this work, a computational approach was taken to understand how lateral inhibition, differential adhesion and programmed cell death can interact to create a mosaic pattern of biologically realistic primary and secondary cells, such as that formed by sensory (primary) and supporting (secondary) cells of the developing chick inner ear epithelium.Results
Four different models that interlaced cellular patterning mechanisms in a variety of ways were examined and their output compared to the mosaic of sensory and supporting cells that develops in the chick inner ear sensory epithelium. The results show that: 1) no single patterning mechanism can create a 2-dimensional mosaic pattern of the regularity seen in the chick inner ear; 2) cell death was essential to generate the most regular mosaics, even through extensive cell death has not been reported for the developing basilar papilla; 3) a model that includes an iterative loop of lateral inhibition, programmed cell death and cell rearrangements driven by differential adhesion created mosaics of primary and secondary cells that are more regular than the basilar papilla; 4) this same model was much more robust to changes in homo- and heterotypic cell-cell adhesive differences than models that considered either fewer patterning mechanisms or single rather than iterative use of each mechanism.Conclusion
Patterning the embryo requires collaboration between multiple mechanisms that operate iteratively. Interlacing these mechanisms into feedback loops not only refines the output patterns, but also increases the robustness of patterning to varying initial cell states. 相似文献44.
Latha Gunturu Manju Raman K. V. Lima John Milton Pattanayak Debasis Singh Ashok K. Chinnusamy Viswanathan Bansal Kailash C. Sambasiva Rao K. R. S. Mohapatra Trilochan 《Plant Cell, Tissue and Organ Culture》2019,137(1):173-179
Plant Cell, Tissue and Organ Culture (PCTOC) - Adventitious root (AR) culturing is an effective approach for obtaining bioactive compounds from the endangered plant species of Oplopanax elatus... 相似文献
45.
The present study was designed to demonstrate the involvement of immune response in experimental atherogenesis. The mitogenic stimulation of lymphocytes and NO production by macrophages in experimental atherogenesis were studied. Further, influence of selenium a potent antioxidant was also studied in the disease process. Three different treatment groups of rats undertaken for study were: group 1, control; group II, high fat diet (HFD) fed group and group III, HFD+Se supplemented group. Atherogenic conditions induced have already been explained earlier [Kang BPS et al. Gen Physiol Biophys, 17 (1998) 71]. Significant increase in 3H-thymidine incorporation was obtained in lymphocytes from HFD fed animals in both presence and absence of mitogen (Con-A). However, these values decreased in group III animals, which were supplemented with selenium. Similarly, NO levels with LPS+ and LPS- macrophages also found to be higher in HFD fed group and decreased in group III. These studies reveal the protective role of selenium in HFD-induced atherogenic process. 相似文献
46.
The effect of cholesterol in a liposomal Muc1 vaccine 总被引:1,自引:0,他引:1
Batenjany MM Boni LT Guo Y Neville ME Bansal S Robb RJ Popescu MC 《Biochimica et biophysica acta》2001,1514(2):280-290
A liposomal Muc1 mucin vaccine for treatment of adenocarcinomas was formulated by incorporating a synthetic Muc1 mucin-based lipopeptide and Lipid A into a DPPC/cholesterol bilayer. Vaccination of mice with the liposomal formulation produced a peptide-specific immune response dependent on the cholesterol content. The response occurred at a threshold of 20-23 mol% cholesterol, and was optimal at cholesterol levels of > or =30 mol%. To understand this cholesterol dependency, we studied the effect of cholesterol on the liposomal bilayer and surface properties. Freeze-fracture electron microscopy showed a unique surface texture that was codependent upon cholesterol (> or =20 mol%) and lipopeptide content. Fluorescence anisotropy measurements exhibited a significant decrease in the rotational motion of 1,6-diphenyl-1,3,5-hexatriene in formulations containing >20 mol% cholesterol and only in the presence of the lipopeptide. At 20 mol% cholesterol and with lipopeptide, DSC showed a significant increase in the main phase transition of the DPPC bilayers, while Raman spectroscopy indicated a more ordered arrangement of DPPC molecules compared to control liposomes containing DPPC/cholesterol alone. Taken together, the data suggest the presence of lipopeptide-rich microdomains at and above a threshold of 20 mol% cholesterol that may play a role in the induction of a peptide-specific immunological response. 相似文献
47.
Kumar D Bansal A Thomas P Sairam M Sharma SK Mongia SS Singh R Selvamurthy W 《International journal of biometeorology》1999,42(4):201-204
High altitude stress leads to lipid peroxidation and free radical formation which results in cell membrane damage in organs
and tissues, and associated mountain diseases. This paper discusses the changes in biochemical parameters and antibody response
on feeding glutamate to male albino Sprague Dawley rats under hypoxic stress. Exposure of rats to simulated hypoxia at 7576
m, for 6 h daily for 5 consecutive days, in an animal decompression chamber at 32±2° C resulted in an increase in plasma malondialdehyde
level with a concomitant decrease in blood glutathione (reduced) level. Supplementation of glutamate orally at an optimal
dose (27 mg/kg body weight) in male albino rats under hypoxia enhanced glutathione level and decreased malondialdehyde concentration
significantly. Glutamate feeding improved total plasma protein and glucose levels under hypoxia. The activities of serum glutamate
oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) and the urea level remained elevated on
glutamate supplementation under hypoxia. Glutamate supplementation increased the humoral response against sheep red blood
cells (antibody titre). These results indicate a possible utility of glutamate in the amelioration of hypoxia-induced oxidative
stress.
Received: 23 March 1998 / Accepted: 19 October 1998 相似文献
48.
Bansal P Mukherjee P Basu SK George A Bal V Rath S 《Journal of immunology (Baltimore, Md. : 1950)》1999,162(8):4430-4437
Pathways for loading exogenous protein-derived peptides on MHC class I are thought to be present mainly in monocyte-lineage cells and to involve phagocytosis- or macropinocytosis-mediated antigenic leakage into either cytosol or extracellular milieu to give peptide access to MHC class I. We show that maleylation of OVA enhanced its presentation to an OVA-specific MHC class I-restricted T cell line by both macrophages and B cells. This enhanced presentation involved uptake through receptors of scavenger receptor (SR)-like ligand specificity, was TAP-1-independent, and was inhibited by low levels (2 mM) of ammonium chloride. No peptide loading of bystander APCs by maleylated (maleyl) OVA-pulsed macrophages was detected. Demaleylated maleyl-OVA showed enhanced MHC class I-restricted presentation through receptor-mediated uptake and remained highly sensitive to 2 mM ammonium chloride. However, if receptor binding of maleyl-OVA was inhibited by maleylated BSA, the residual presentation was relatively resistant to 2 mM ammonium chloride. Maleyl-OVA directly introduced into the cytosol via osmotic lysis of pinosomes was poorly presented, confirming that receptor-mediated presentation of exogenous maleyl-OVA was unlikely to involve a cytosolic pathway. Demaleylated maleyl-OVA was well presented as a cytosolic Ag, consistent with the dependence of cytosolic processing on protein ubiquitination. Thus, receptor-specific delivery of exogenous protein Ags to APCs can result in enhanced MHC class I-restricted presentation, suggesting that the exogenous pathway of peptide loading for MHC class I may be a constitutive property dependent mainly on the quantity of Ag taken up by APCs. 相似文献
49.
Myelin-associated glycoprotein (MAG) has been implicated in inhibition of nerve regeneration in the CNS. This results from interactions between MAG and the Nogo receptor and gangliosides on the apposing axon, which generates intracellular inhibitory signals in the neuron. However, because myelin-axon signaling is bidirectional, we undertook an analysis of potential MAG-activated signaling in oligodendrocytes (OLs). In this study, we show that antibody cross-linking of MAG on the surface of OLs (to mimic axonal binding) leads to the redistribution of MAG into detergent (TX-100)-insoluble complexes, hyperphosphorylation of Fyn, dephosphorylation of serine and threonine residues in specific proteins, including lactate dehydrogenase and the beta subunit of the trimeric G-protein-complex, and cleavage of alpha-fodrin followed by a transient depolymerization of actin. We propose that these changes are part of a signaling cascade in OLs associated with MAG function as a mediator of axon-glial communication which might have implications for the mutual regulation of the formation and stability of axons and myelin. 相似文献
50.
Bansal SK Layloff T Bush ED Hamilton M Hankinson EA Landy JS Lowes S Nasr MM St Jean PA Shah VP 《AAPS PharmSciTech》2004,5(1):151-158
The purpose of the use of analytical instruments is to generate reliable data. Instrument qualification helps fulfill this
purpose. No authoritative guide exists that considers the risk of instrument failure and combines that risk with users' scientific
knowledge and ability to use the instrument to deliver reliable and consistent data. In the absence of such a guide, the qualification
of analytical instruments has become a subjective and often fruitless document-generating exercise.
Taking its cue from the new FDA initiative, “Pharmaceutical GMP's for the 21st Century,” an efficient, science- and risk-based
process for AIQ was discussed at a workshop on analytical instrument qualification. This report represents the distillate
of deliberations on the complicated issues associated with the various stages of analytical instrument qualification. It emphasizes
AIQ's place in the overall process of obtaining quality reliable data from analytical instruments and offers an efficient
process for its performance, one that focuses on scientific value rather than on producing documents. Implementing such a
process should remove ambiguous interpretations by various groups. 相似文献