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Abstract
Acquisition of cell type-specific properties in the nervous system is likely a process of sequential restriction in developmental potential. At least two classes of pluripotent stem cells, neuroepithelial (NEP) stem cells and EGF-dependent neurosphere stem cells, have been identified in distinct spatial and temporal domains. Pluripotent stem cells likely generate central nervous system (CNS) and peripheral nervous system (PNS) derivatives via the generation of intermediate lineage-restricted precursors that differ from each other and from multipotent stem cells. Neuronal precursors termed neuronal-restricted precursors (NRPs), multiple classes of glial precursors termed glial-restricted precursors (GRPs), oligodendrocyte-type 2 astrocytes (O2As), astrocyte precursor cells (APCs), and PNS precursors termed neural crest stem cells (NCSCs) have been identified. Multipotent stem cells and restricted precursor cells can be isolated from embryonic stem (ES) cell cultures providing a non-fetal source of such cells. Analysis in multiple species illustrates similarities between rat, mouse, and human cell differentiation raising the possibility that similar factors and markers may be used to isolate precursor cells from human tissue or ES cells. Anat Rec (New Anat): 257:137-143, 1999.
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Mujtaba T, Piper DR, Kalyani A, Groves AK, Lucero MT, Rao MS. Lineage-restricted neural precursors can be isolated from both the mouse neural tube and cultured ES cells. Dev Biol 1999; 214:113-27. [PMID: 10491261 DOI: 10.1006/dbio.1999.9418] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We have previously identified multipotent neuroepithelial (NEP) stem cells and lineage-restricted, self-renewing precursor cells termed NRPs (neuron-restricted precursors) and GRPs (glial-restricted precursors) present in the developing rat spinal cord (A. Kalyani, K. Hobson, and M. S. Rao, 1997, Dev. Biol. 186, 202-223; M. S. Rao and M. Mayer-Proschel, 1997, Dev. Biol. 188, 48-63; M. Mayer-Proschel, A. J. Kalyani, T. Mujtaba, and M. S. Rao, 1997, Neuron 19, 773-785). We now show that cells identical to rat NEPs, NRPs, and GRPs are present in mouse neural tubes and that immunoselection against cell surface markers E-NCAM and A2B5 can be used to isolate NRPs and GRPs, respectively. Restricted precursors similar to NRPs and GRPs can also be isolated from mouse embryonic stem cells (ES cells). ES cell-derived NRPs are E-NCAM immunoreactive, undergo self-renewal in defined medium, and differentiate into multiple neuronal phenotypes in mass culture. ES cells also generate A2B5-immunoreactive cells that are similar to E9 NEP-cell-derived GRPs and can differentiate into oligodendrocytes and astrocytes. Thus, lineage restricted precursors can be generated in vitro from cultured ES cells and these restricted precursors resemble those derived from mouse neural tubes. These results demonstrate the utility of using ES cells as a source of late embryonic precursor cells.
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78
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Zhu Y, Qi C, Jain S, Le Beau MM, Espinosa R, Atkins GB, Lazar MA, Yeldandi AV, Rao MS, Reddy JK. Amplification and overexpression of peroxisome proliferator-activated receptor binding protein (PBP/PPARBP) gene in breast cancer. Proc Natl Acad Sci U S A 1999; 96:10848-53. [PMID: 10485914 PMCID: PMC17971 DOI: 10.1073/pnas.96.19.10848] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peroxisome proliferator-activated receptor binding protein (PBP), a nuclear receptor coactivator, interacts with estrogen receptor alpha (ERalpha) in the absence of estrogen. This interaction was enhanced in the presence of estrogen but was reduced in the presence of antiestrogen, tamoxifen. Transfection of PBP in CV-1 cells resulted in enhancement of estrogen-dependent transcription, indicating that PBP serves as a coactivator in ER signaling. To examine whether overexpression of PBP plays a role in breast cancer because of its coactivator function in ER signaling, we determined the levels of PBP expression in breast tumors. High levels of PBP expression were detected in approximately 50% of primary breast cancers and breast cancer cell lines by ribonuclease protection analysis, in situ hybridization, and immunoperoxidase staining. Fluorescence in situ hybridization of human chromosomes revealed that the PBP gene is located on chromosome 17q12, a region that is amplified in some breast cancers. We found PBP gene amplification in approximately 24% (6/25) of breast tumors and approximately 30% (2/6) of breast cancer cell lines, implying that PBP gene overexpression can occur independent of gene amplification. This gene comprises 17 exons that, together, span >37 kilobases. The 5'-flanking region of 2.5 kilobase pairs inserted into a luciferase reporter vector revealed that the promoter activity in CV-1 cells increased by deletion of nucleotides from -2,500 to -273. The -273 to +1 region, which exhibited high promoter activity, contains a typical CCAT box and multiple cis-elements such as C/EBPbeta, YY1, c-Ets-1, AP1, AP2, and NFkappaB binding sites. These observations, in particular PBP gene amplification, suggest that PBP, by its ability to function as ERalpha coactivator, might play a role in mammary epithelial differentiation and in breast carcinogenesis.
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79
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Coombs GS, Rao MS, Olson AJ, Dawson PE, Madison EL. Revisiting catalysis by chymotrypsin family serine proteases using peptide substrates and inhibitors with unnatural main chains. J Biol Chem 1999; 274:24074-9. [PMID: 10446178 DOI: 10.1074/jbc.274.34.24074] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chymotrypsin family serine proteases play essential roles in key biological and pathological processes and are frequently targets of drug discovery efforts. This large enzyme family is also among the most advanced model systems for detailed studies of enzyme mechanism and structure/function relationships. Productive interactions between these enzymes and their substrates are widely believed to mimic the "canonical" interactions between serine proteases and "standard" inhibitors observed in numerous protease-inhibitor complexes. To test this central hypothesis we have synthesized and characterized a series of peptide analogs, based on model substrates and inhibitors of trypsin, that contain unnatural main chains. These results call into question a long accepted theory regarding the interaction of chymotrypsin family serine proteases with substrates and suggest that the canonical interactions observed between these enzymes and standard inhibitors may represent nonproductive rather than productive, substrate-like interactions.
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Abstract
Acquisition of cell type-specific properties in the nervous system is likely a process of sequential restriction in developmental potential. At least two classes of pluripotent stem cells, neuroepithelial (NEP) stem cells and EGF-dependent neurosphere stem cells, have been identified in distinct spatial and temporal domains. Pluripotent stem cells likely generate central nervous system (CNS) and peripheral nervous system (PNS) derivatives via the generation of intermediate lineage-restricted precursors that differ from each other and from multipotent stem cells. Neuronal precursors termed neuronal-restricted precursors (NRPs), multiple classes of glial precursors termed glial-restricted precursors (GRPs), oligodendrocyte-type 2 astrocytes (O2As), astrocyte precursor cells (APCs), and PNS precursors termed neural crest stem cells (NCSCs) have been identified. Multipotent stem cells and restricted precursor cells can be isolated from embryonic stem (ES) cell cultures providing a non-fetal source of such cells. Analysis in multiple species illustrates similarities between rat, mouse, and human cell differentiation raising the possibility that similar factors and markers may be used to isolate precursor cells from human tissue or ES cells. Anat Rec (New Anat): 257:137-143, 1999.
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81
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Rao MS, Pujari AK. A new neural network architecture with associative memory, pruning and order-sensitive learning. Int J Neural Syst 1999; 9:351-70. [PMID: 10586992 DOI: 10.1142/s0129065799000332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A new paradigm of neural network architecture is proposed that works as associative memory along with capabilities of pruning and order-sensitive learning. The network has a composite structure wherein each node of the network is a Hopfield network by itself. The Hopfield network employs an order-sensitive learning technique and converges to user-specified stable states without having any spurious states. This is based on geometrical structure of the network and of the energy function. The network is so designed that it allows pruning in binary order as it progressively carries out associative memory retrieval. The capacity of the network is 2n, where n is the number of basic nodes in the network. The capabilities of the network are demonstrated by experimenting on three different application areas, namely a Library Database, a Protein Structure Database and Natural Language Understanding.
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Kalyani AJ, Rao MS. Cell lineage in the developing neural tube. Biochem Cell Biol 1999; 76:1051-68. [PMID: 10392716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
Acquisition of cell type specific properties in the spinal cord is a process of sequential restriction in developmental potential. A multipotent stem cell of the nervous system, the neuroepithelial cell, generates central nervous system and peripheral nervous system derivatives via the generation of intermediate lineage restricted precursors that differ from each other and from neuroepithelial cells. Intermediate lineage restricted neuronal and glial precursors termed neuronal restricted precursors and glial restricted precursors, respectively, have been identified. Differentiation is influenced by extrinsic environmental signals that are stage and cell type specific. Analysis in multiple species illustrates similarities between chick, rat, mouse, and human cell differentiation. The utility of obtaining these precursor cell types for gene discovery, drug screening, and therapeutic applications is discussed.
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83
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Hashimoto T, Fujita T, Usuda N, Cook W, Qi C, Peters JM, Gonzalez FJ, Yeldandi AV, Rao MS, Reddy JK. Peroxisomal and mitochondrial fatty acid beta-oxidation in mice nullizygous for both peroxisome proliferator-activated receptor alpha and peroxisomal fatty acyl-CoA oxidase. Genotype correlation with fatty liver phenotype. J Biol Chem 1999; 274:19228-36. [PMID: 10383430 DOI: 10.1074/jbc.274.27.19228] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fatty acid beta-oxidation occurs in both mitochondria and peroxisomes. Long chain fatty acids are also metabolized by the cytochrome P450 CYP4A omega-oxidation enzymes to toxic dicarboxylic acids (DCAs) that serve as substrates for peroxisomal beta-oxidation. Synthetic peroxisome proliferators interact with peroxisome proliferator activated receptor alpha (PPARalpha) to transcriptionally activate genes that participate in peroxisomal, microsomal, and mitochondrial fatty acid oxidation. Mice lacking PPARalpha (PPARalpha-/-) fail to respond to the inductive effects of peroxisome proliferators, whereas those lacking fatty acyl-CoA oxidase (AOX-/-), the first enzyme of the peroxisomal beta-oxidation system, exhibit extensive microvesicular steatohepatitis, leading to hepatocellular regeneration and massive peroxisome proliferation, implying sustained activation of PPARalpha by natural ligands. We now report that mice nullizygous for both PPARalpha and AOX (PPARalpha-/- AOX-/-) failed to exhibit spontaneous peroxisome proliferation and induction of PPARalpha-regulated genes by biological ligands unmetabolized in the absence of AOX. In AOX-/- mice, the hyperactivity of PPARalpha enhances the severity of steatosis by inducing CYP4A family proteins that generate DCAs and since they are not metabolized in the absence of peroxisomal beta-oxidation, they damage mitochondria leading to steatosis. Blunting of microvesicular steatosis, which is restricted to few liver cells in periportal regions in PPARalpha-/- AOX-/- mice, suggests a role for PPARalpha-induced genes, especially members of CYP4A family, in determining the severity of steatosis in livers with defective peroxisomal beta-oxidation. In age-matched PPARalpha-/- mice, a decrease in constitutive mitochondrial beta-oxidation with intact constitutive peroxisomal beta-oxidation system contributes to large droplet fatty change that is restricted to centrilobular hepatocytes. These data define a critical role for both PPARalpha and AOX in hepatic lipid metabolism and in the pathogenesis of specific fatty liver phenotype.
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84
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Sudhagar K, Chandrasekar S, Rao MS, Ravichandran R. Effect of granulocyte macrophage colony stimulating factor on hepatitis-B vaccination in haemodialysis patients. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1999; 47:602-4. [PMID: 10999156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVES Haemodialysis patients often fail to respond to hepatitis B vaccination. There are various agents that can be used as vaccine adjuvant in chronic renal failure patients on haemodialysis. In this study, the adjuvant effect of granulocyte macrophage colony stimulating factor (GMCSF) is compared with that of control subjects. METHODS In this study, eight patients were started on 150 mcg of GMCSF subcutaneously 24 hours prior to intramuscular hepatitis B vaccination (20 mcg of genetically engineered vaccine at the same site). The antibody response to surface antigen (anti HBsAg) in these patients were compared with those of eight control subjects who received standard three doses of monthly 40 mcg of same hepatitis B vaccine. RESULTS In the control study, only two patients developed significant antibody response to surface antigen whereas seven of eight patients in GMCSF group developed significant antibody titres (> 10 IU/L). The sero-protection rate was 87.5% in GMCSF group and 25% in control group. CONCLUSION This study shows that GMCSF offers significantly better seroprotection against hepatitis B compared to standard dose of vaccination in patients with chronic renal failure on haemodialysis.
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85
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Qi C, Zhu Y, Pan J, Usuda N, Maeda N, Yeldandi AV, Rao MS, Hashimoto T, Reddy JK. Absence of spontaneous peroxisome proliferation in enoyl-CoA Hydratase/L-3-hydroxyacyl-CoA dehydrogenase-deficient mouse liver. Further support for the role of fatty acyl CoA oxidase in PPARalpha ligand metabolism. J Biol Chem 1999; 274:15775-80. [PMID: 10336479 DOI: 10.1074/jbc.274.22.15775] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxisomes contain a classical L-hydroxy-specific peroxisome proliferator-inducible beta-oxidation system and also a second noninducible D-hydroxy-specific beta-oxidation system. We previously generated mice lacking fatty acyl-CoA oxidase (AOX), the first enzyme of the L-hydroxy-specific classical beta-oxidation system; these AOX-/- mice exhibited sustained activation of peroxisome proliferator-activated receptor alpha (PPARalpha), resulting in profound spontaneous peroxisome proliferation in liver cells. These observations implied that AOX is responsible for the metabolic degradation of PPARalpha ligands. In this study, the function of enoyl-CoA hydratase/L-3-hydroxyacyl-CoA dehydrogenase (L-PBE), the second enzyme of this peroxisomal beta-oxidation system, was investigated by disrupting its gene. Mutant mice (L-PBE-/-) were viable and fertile and exhibited no detectable gross phenotypic defects. L-PBE-/- mice showed no hepatic steatosis and manifested no spontaneous peroxisome proliferation, unlike that encountered in livers of mice deficient in AOX. These results indicate that disruption of classical peroxisomal fatty acid beta-oxidation system distal to AOX step does not interfere with the inactivation of endogenous ligands of PPARalpha, further confirming that the AOX gene is indispensable for the physiological regulation of this receptor. The absence of appreciable changes in lipid metabolism also indicates that enoyl-CoAs, generated in the classical system in L-PBE-/- mice are diverted to D-hydroxy-specific system for metabolism by D-PBE. When challenged with a peroxisome proliferator, L-PBE-/- mice showed increases in the levels of hepatic mRNAs and proteins that are regulated by PPARalpha except for appreciable blunting of peroxisome proliferative response as compared with that observed in hepatocytes of wild type mice similarly treated. This blunting of peroxisome proliferative response is attributed to the absence of L-PBE protein in L-PBE-/- mouse liver, because all other proteins are induced essentially to the same extent in both wild type and L-PBE-/- mice.
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86
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Reddy NK, Raju PR, Kapoor S, Rao MS, Reddy RP, Sastry BK, Raju BS. Prospective observational study of primary angioplasty of the infarct-related artery for acute myocardial infarction. Indian Heart J 1999; 51:167-72. [PMID: 10407544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
Primary angioplasty has been shown to reduce rates of in-hospital mortality, recurrent ischaemia and infarction. However, the role of primary stenting and abciximab is presently undergoing evaluation. This study attempted to examine the feasibility, safety and outcomes of primary angioplasty in the treatment of acute myocardial infarction. Data in 100 patients who underwent primary angioplasty for evolving acute myocardial infarction was prospectively analysed to assess the safety and efficacy of various modalities. Twenty patients were in Killip class III and above. Multivessel (2 or more vessels) disease was noted in more than 52 cases. Procedural success was 99 percent; 86 patients received primary stenting, majority of them had Kalam-Raju stent implantation. Adjunct treatment included abciximab infusion in 22 and intra-aortic balloon pump support in 12. Overall mortality rate was six percent with a mortality of 2.2 percent in non-cardiogenic shock patients. Recurrent ischaemic events were noted in five, three of them had successful reperfusion with repeat angioplasty. None of the patients had emergency coronary artery bypass surgery. It is concluded that primary angioplasty is safe and effective with high procedural success. Recurrent ischaemic events are low, possibly due to routine use of stenting and selective use of abciximab.
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87
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Qi C, Zhu Y, Pan J, Yeldandi AV, Rao MS, Maeda N, Subbarao V, Pulikuri S, Hashimoto T, Reddy JK. Mouse steroid receptor coactivator-1 is not essential for peroxisome proliferator-activated receptor alpha-regulated gene expression. Proc Natl Acad Sci U S A 1999; 96:1585-90. [PMID: 9990068 PMCID: PMC15526 DOI: 10.1073/pnas.96.4.1585] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/1998] [Accepted: 12/15/1998] [Indexed: 01/22/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors, and it is assumed that the biological effects of these receptors depend on interactions with recently identified coactivators, including steroid receptor coactivator-1 (SRC-1). We assessed the in vivo function of SRC-1 on the PPARalpha-regulated gene expression in liver by generating mice in which the SRC-1 gene was inactivated by gene targeting. The homozygous (SRC-1(-/-)) mice were viable and fertile and exhibited no detectable gross phenotypic defects. When challenged with a PPARalpha ligand, such as ciprofibrate or Wy-14,643, the SRC-1(-/-) mice displayed typical pleiotropic responses, including hepatomegaly, peroxisome proliferation in hepatocytes, and increased mRNA and protein levels of genes that are regulated by PPARalpha. These alterations were indistinguishable from those exhibited by SRC-1(+/+) wild-type mice fed either ciprofibrate- or Wy-14, 643-containing diets. These results indicate that SRC-1 is not essential for PPARalpha-mediated transcriptional activation in vivo and suggest redundancy in nuclear receptor coactivators.
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88
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Kalyani AJ, Mujtaba T, Rao MS. Expression of EGF receptor and FGF receptor isoforms during neuroepithelial stem cell differentiation. JOURNAL OF NEUROBIOLOGY 1999; 38:207-24. [PMID: 10022567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
To characterize the role of epidermal growth factor (EGF) and fibroblast growth factor (FGF) in regulating neuroepithelial stem cells differentiation, we have examined the expression of FGF, EGF, and their receptors by neuroepithelial (NEP) cells and their derivatives. Our results indicate that undifferentiated NEP cells express a subset of FGF receptor (FGFR) isoforms, but do not express platelet-derived growth factor receptors (PDGFRs) or epidermal growth factor receptor (EGFR). The FGFR pattern of expression by differentiated neuron and glial cells differs from that found on NEP stem cells. FGFR-4 is uniquely expressed on NEP cells, while FGFR-1 is expressed by both NEP cells and neurons, and FGFR-2 is down-regulated during neuronal differentiation. FGFRs present on astrocytes and oligodendrocytes also represent a subset of those present on NEP cells. Expression of FGF and EGF by NEP cells and their progeny was also examined. NEP cells synthesize detectable levels of both FGF-1 and FGF-2, and EGF. FGF-1 and FGF-2 synthesis is likely to be biologically relevant, as cells grown at high density do not require exogenous FGF for their survival and cells grown in the presence of neutralizing antibodies to FGF show a reduction in cell survival and division. Thus, neuroepithelial cells synthesize and respond to FGF, but not to EGF, and are therefore distinct from other neural stem cells (neurospheres). The unique pattern of expression of FGF isoforms may serve to distinguish NEP cells from their more differentiated progeny.
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Abstract
In order to understand the structural basis of Factor Xa (FXa) specificity, structural complexes of FXa with its synthetic inhibitors are determined using a computational docking approach. The AutoDock suite of programs is used to determine the binding modes of the synthetic inhibitors such as 3- and 4-amidinobenzylphenyl ether (ABP), amidinophenyl pyruvic acid (APPA), diamidinobenzofuranyl ethene (DABE), and DX-9065a 2-(5'-amidino-2'-benzofuranyl)-3-(7'amidino-2'-napthyl)-propionic acid (ABAP) to FXa. The synthetic inhibitors docked in the present study are different in size, nature of linkage, and properties. Two sets of simulations were carried out for synthetic inhibitors docking to FXa. In the first set of simulations, no explicit water molecules were included. In the second set of simulations two explicit solvent molecules were considered. In all the computationally predicted synthetic inhibitor complexes of FXa, the specificity pocket residue Asp-189 is involved in hydrogen bonding with the bound inhibitor. The active site water molecule WAT522 is involved in hydrogen bonding with all the bound inhibitors. The computed energies clearly discriminate the high affinity from low affinity binders.
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90
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Abstract
We describe a ciliated hepatic foregut cyst that was clinically considered neoplastic because it was large, bilocular, and associated with a high serological level of carbohydrate antigen 19-9 (CA 19-9). Histologically, the wall of the cyst showed characteristic pseudopapillae lined by ciliated stratified columnar epithelium with interspersed goblet cells and underlying smooth muscle. The epithelium was strongly immunoreactive for CA 19-9. We therefore conclude that large size, multilocularity, and elevated CA 19-9 do not exclude ciliated hepatic foregut cysts from diagnostic consideration.
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91
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Lee JC, Greig A, Ravindranathan A, Parks TN, Rao MS. Molecular analysis of AMPA-specific receptors: subunit composition, editing, and calcium influx determination in small amounts of tissue. BRAIN RESEARCH. BRAIN RESEARCH PROTOCOLS 1998; 3:142-54. [PMID: 9813290 DOI: 10.1016/s1385-299x(98)00035-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glutamate activates three distinct classes of ionotropic receptors: AMPA, kainate and NMDA. AMPA receptors (AMPARs) are of particular importance as they mediate the majority of fast excitatory synaptic transmission and are implicated in a variety of neurological disorders [B. Bettler, C. Mulle, AMPA and kainate receptors, Neuropharmacology 34 (1995) 123-139]. Functional AMPARs are believed to be a heteromer comprising a combination of four closely related subunits, GluRs1-4 [B. Bettler, C. Mulle, AMPA and kainate receptors, Neuropharmacology 34 (1995) 123-139]. Diversity of AMPARs is obtained through multiple combinations of AMPAR subunits, by alternative splicing of subunits at the flip/flop and/or C-terminal sites, and by mRNA editing of a single amino acid at multiple sites [M. Hollmann, M. Hartley, S. Heinemann, Ca2+ permeability of KA-AMPA-gated glutamate receptor channel depends on subunit composition, Science 252 (1991) 851-853; B. Sommer, K. Keinanen, T.A. Verdoorn, W. Wisden, N. Burhashev, A. Herb, M. Kohler, T. Takagi, B. Sakmann, P.H. Seeburg, Flip and flop: a cell-specific functional switch in glutamate-operated channels in the CNS, Science 249 (1990) 1580-1585; B. Sommer, M. Kohler, R. Sprengel, P.H. Seeburg, RNA editing in brain controls a determinant of ion flow in glutamate-gated channels, Cell 67 (1991)]. The subunit combination, editing status, and splice variant expression have profound effects on channel kinetics and can serve as predictors of the channel's properties [M. Hollmann, M. Hartley, S. Heinemann, Ca2+ permeability of KA-AMPA-gated glutamate receptor channel depends on subunit composition, Science 252 (1991) 851-853; B. Sommer, K. Keinanen, T.A. Verdoorn, W. Wisden, N. Burhashev, A. Herb, M. Kohler, T. Takagi, B. Sakmann, P.H. Seeburg, Flip and flop: a cell-specific functional switch in glutamate-operated channels in the CNS, Science 249 (1990) 1580-1585; B. Sommer, M. Kohler, R. Sprengel, P.H. Seeburg, RNA editing in brain controls a determinant of ion flow in glutamate-gated channels, Cell 67 (1991)]. In this manuscript, we detail procedures for profiling AMPAR composition, namely: relative subunit ratios, expression of flip/flop isoforms, Q/R and R/G editing status, and Ca2+ permeability using small amounts of cDNA from identified cell populations.
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Kalyani AJ, Piper D, Mujtaba T, Lucero MT, Rao MS. Spinal cord neuronal precursors generate multiple neuronal phenotypes in culture. J Neurosci 1998; 18:7856-68. [PMID: 9742154 PMCID: PMC2966285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Neuronal restricted precursors (NRPs) () can generate multiple neurotransmitter phenotypes during maturation in culture. Undifferentiated E-NCAM+ (embryonic neural cell adhesion molecule) immunoreactive NRPs are mitotically active and electrically immature, and they express only a subset of neuronal markers. Fully mature cells are postmitotic, process-bearing cells that are neurofilament-M and synaptophysin immunoreactive, and they synthesize and respond to different subsets of neurotransmitter molecules. Mature neurons that synthesize and respond to glycine, glutamate, GABA, dopamine, and acetylcholine can be identified by immunocytochemistry, RT-PCR, and calcium imaging in mass cultures. Individual NRPs also generate heterogeneous progeny as assessed by neurotransmitter response and synthesis, demonstrating the multipotent nature of the precursor cells. Differentiation can be modulated by sonic hedgehog (Shh) and bone morphogenetic protein (BMP)-2/4 molecules. Shh acts as a mitogen and inhibits differentiation (including cholinergic differentiation). BMP-2 and BMP-4, in contrast, inhibit cell division and promote differentiation (including cholinergic differentiation). Thus, a single neuronal precursor cell can differentiate into multiple classes of neurons, and this differentiation can be modulated by environmental signals.
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Rao MS, Rao PS, Toth G, Balazs B, Duddeck H. A revised structure for crotaramosmin from crotolaria ramosissima. JOURNAL OF NATURAL PRODUCTS 1998; 61:1148-1149. [PMID: 9748387 DOI: 10.1021/np980043h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The structure of crotaramosmin has been reassigned to 1-(5-hydroxy-2, 2-dimethyl-2H-chromen-6-yl)-3-(4-hydroxyphenyl)-propanone (1) as determined by extensive NMR investigation.
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Jain S, Pulikuri S, Zhu Y, Qi C, Kanwar YS, Yeldandi AV, Rao MS, Reddy JK. Differential expression of the peroxisome proliferator-activated receptor gamma (PPARgamma) and its coactivators steroid receptor coactivator-1 and PPAR-binding protein PBP in the brown fat, urinary bladder, colon, and breast of the mouse. THE AMERICAN JOURNAL OF PATHOLOGY 1998; 153:349-54. [PMID: 9708794 PMCID: PMC1852994 DOI: 10.1016/s0002-9440(10)65577-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/02/1998] [Indexed: 11/19/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) regulate genes involved in lipid metabolism and adipocyte differentiation. Steroid receptor coactivator-1 (SRC-1) and PPAR-binding protein (PBP) interact with PPARgamma and act as coactivators to enhance ligand-dependent transcription. We report here that PPARgamma, SRC-1, and PBP are differentially expressed in the brown fat, transitional epithelium of the urinary bladder, colonic mucosa, and mammary epithelium of the adult mouse. PPARgamma and PBP are expressed in the transitional epithelium of urinary bladder and in brown adipose tissue, but not SRC-1. In the colonic mucosa, PPARgamma expression occurs throughout the villi, whereas the expression of both SRC-1 and PBP is confined mostly to the crypts. The expression of both SRC-1 and PBP is prominent in the breast epithelium of nonpregnant, pregnant, and lactating mice, whereas PPARgamma expression appeared prominent during lactation. During early embryonic development, PPARgamma, SRC-1, and PBP are differentially expressed, with only limited cell types displaying overlapping expression. PPARgamma and PBP expression overlapped in the brown fat and urogenital sinus at stage E15.5 of embryogenesis, whereas SRC-1 expression occurred mostly in neuroepithelium and cartilage between stages E9.5 and E13.5 of embryogenesis.
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Abstract
Cultured spinal cord neuroepithelial (NEP) cells can differentiate into neurons, oligodendrocytes and astrocytes and are morphologically and antigenically distinct from neural crest stem cells (NCSCs) that generate the PNS. NEP cells, however, can generate p75/nestin-immunoreactive cells that are morphologically and antigenically similar to previously characterized NCSCs. NEP-derived p75-immunoreactive cells differentiate into peripheral neurons, smooth muscle, and Schwann cells in mass and clonal culture. Clonal analysis of NEP cells demonstrates that a common NEP progenitor cell generated both CNS and PNS phenotypes. Differentiation into NCSCs was promoted by BMP-2/4 and differentiation did not require cells to divide, indicating that BMP played an instructive role in the differentiation process. Thus, individual NEP cells are multipotent and can differentiate into most major types of cell in the CNS and PNS and that PNS differentiation involves a transition from a NEP stem to another more limited, p75-immunoreactive, neural crest stem cell.
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96
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Fan CY, Pan J, Usuda N, Yeldandi AV, Rao MS, Reddy JK. Steatohepatitis, spontaneous peroxisome proliferation and liver tumors in mice lacking peroxisomal fatty acyl-CoA oxidase. Implications for peroxisome proliferator-activated receptor alpha natural ligand metabolism. J Biol Chem 1998; 273:15639-45. [PMID: 9624157 DOI: 10.1074/jbc.273.25.15639] [Citation(s) in RCA: 273] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Peroxisomal beta-oxidation system consists of four consecutive reactions to preferentially metabolize very long chain fatty acids. The first step of this system, catalyzed by acyl-CoA oxidase (AOX), converts fatty acyl-CoA to 2-trans-enoyl-CoA. Herein, we show that mice deficient in AOX exhibit steatohepatitis, increased hepatic H2O2 levels, and hepatocellular regeneration, leading to a complete reversal of fatty change by 6 to 8 months of age. The liver of AOX-/- mice with regenerated hepatocytes displays profound generalized spontaneous peroxisome proliferation and increased mRNA levels of genes that are regulated by peroxisome proliferator-activated receptor alpha (PPARalpha). Hepatic adenomas and carcinomas develop in AOX-/- mice by 15 months of age due to sustained activation of PPARalpha. These observations implicate acyl-CoA and other putative substrates for AOX, as biological ligands for PPARalpha; thus, a normal AOX gene is indispensable for the physiological regulation of PPARalpha.
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97
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Choksi SK, Rao MS. Comparison of two film holders for periapical radiography performed by dental students. MSDA JOURNAL : JOURNAL OF THE MARYLAND STATE DENTAL ASSOCIATION 1998; 39:23-6. [PMID: 9569872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A clinical study was done at Howard University, College of Dentistry, to compare the difference in the incidence of radiographic technique faults between two similar intraoral film-holding, beam-aligning, devices in a series of 1,248 radiographs. The primary difference between a conventional Extension Cone Paralleling (XCP-I) film holder and a modified, all-metal, Extension Cone Paralleling (XCP-II) film holder is the incorporation of a collimated rectangular x-ray-beam-restricting plate. This latter film holder possessed an indicator rod attached to the bite block and a metal shield to reduce primary and back-scattered radiation behind the film. In the oral diagnosis clinic, 78 dentulous patients were randomly selected and randomly divided into two groups of 39 patients. One of the two film holders was used separately for the two groups of patients, and a full mouth series of 16 periapical radiographs were made for each patient. The difference in the occurrence of total errors between the two instruments was not statistically significant. However, the conventional instrument was associated with significantly more errors in improper film positioning, while the modified device had significantly more errors in cone cutting (p < 0.01).
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98
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Rao MS, Noble M, Mayer-Pröschel M. A tripotential glial precursor cell is present in the developing spinal cord. Proc Natl Acad Sci U S A 1998; 95:3996-4001. [PMID: 9520481 PMCID: PMC19951 DOI: 10.1073/pnas.95.7.3996] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have isolated a tripotential glial precursor cell population from spinal cords of E13.5 rats. In vitro, these A2B5+E-NCAM- glial-restricted precursor (GRP) cells can undergo extensive self-renewal, and can differentiate into oligodendrocytes and two distinct astrocyte populations, but do not differentiate into neurons. The differentiation potential of GRP cells is retained through at least three cycles of expansion and recloning. Unlike oligodendrocyte-type 2 astrocyte progenitor cells, freshly isolated GRP cells do not respond to platelet-derived growth factor as a mitogen or survival factor, nor do GRP cells differentiate into oligodendrocytes--or even survive--when plated in mitogen-free chemically defined medium. Exposure to fetal calf serum induces GRP cells to differentiate into A2B5- fibroblast-like astrocytes, whereas growth in the presence of basic fibroblast growth factor and ciliary neurotrophic factor induces the generation of A2B5+ process-bearing astrocytes. The early appearance of GRP cells during spinal cord development suggests that they may represent the earliest GRP cell population.
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99
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Rao MS, Subbarao V. Sex differences in dehydroepiandrosterone-induced hepatocarcinogenesis in the rat. Cancer Lett 1998; 125:111-6. [PMID: 9566704 DOI: 10.1016/s0304-3835(97)00498-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Dehydroepiandrosterone (DHEA), a steroid secreted by the adrenal gland, is a peroxisome proliferator and a hepatocarcinogen. Previously, we have shown that 15-week-old male rats given DHEA in AIN-76 diet without vitamin E developed liver tumors. In the present study, we have examined the carcinogenic effect of DHEA in 5-6-week-old male rats and in intact and ovariectomized female rats. Rats were fed Purina chow containing DHEA at a concentration of 0.45% for 100 weeks and livers were evaluated for tumor incidence and multiplicity. In male rats the incidence of total tumors and hepatocellular carcinomas (HCC) was 94 and 81%, respectively, with 1.9 +/- 0.3 (mean +/- SD) tumors per liver. In intact and ovariectomized females the total tumor incidence was 46 and 60%, respectively. However, the incidence of HCC and the mean number of tumors were similar in both intact and ovariectomized groups. Phenotypically the neoplastic nodules and HCC in female rats were negative for gamma-glutamyltranspeptidase. The results of these studies further confirm that DHEA is a hepatocarcinogen in male and female rats. The possible reasons for the decreased incidence of liver tumors in females in relation to the peroxisome proliferative effect of DHEA is discussed.
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100
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Rao MS, Vaijyanath P, Taneja K, Dubey B, Manchanda SC, Venugopal P. Recurrent pseudoaneurysm of the left ventricle with subcutaneous herniation into the chest wall. A case report. Tex Heart Inst J 1998; 25:309-11. [PMID: 9885110 PMCID: PMC325579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Pseudoaneurysm of the left ventricle is rare, and recurrence is extremely rare. We report the case of a 62-year-old man who presented at our hospital with a painless pulsatile swelling in the left breast. He had undergone coronary artery bypass grafting and left-ventricular aneurysmectomy 14 years earlier. On investigation, the swelling was diagnosed to be a pseudoaneurysm of the left ventricle with subcutaneous herniation. The extreme rarity of this condition prompted us to report the case. The investigative techniques and the surgical strategy are discussed.
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