Usman Ahmed | Federal Urdu University of Arts, Science and Technology,Islamabad, Pakistan (original) (raw)
Papers by Usman Ahmed
Journal of Neurochemistry, 2005
Increased damage to proteins by glycation, oxidation and nitration has been implicated in neurona... more Increased damage to proteins by glycation, oxidation and nitration has been implicated in neuronal cell death leading to Alzheimer's disease (AD). Protein glycation, oxidation and nitration adducts are consequently formed. Quantitative screening of these adducts in CSF may provide a biochemical indicator for the diagnosis of AD. To assess this, we measured 11 glycation adducts, three oxidation adducts and a nitration adduct, determining both protein adduct residues and free adducts, in CSF samples of age-matched normal healthy subjects (n ¼ 18) and subjects with Alzheimer's disease (n ¼ 32). In CSF protein, the concentrations of 3-nitrotyrosine, N e -carboxymethyl-lysine, 3-deoxyglucosone-derived hydroimidazolone and N-formylkynurenine residues were increased in subjects with Alzheimer's disease. In CSF ultrafiltrate, the concentrations of 3-nitrotyrosine, methylglyoxal-derived hydroimidazolone and glyoxal-derived hydroimidazolone free adducts were also increased. The Mini-Mental State Examination (MMSE) score correlated negatively with 3-nitrotyrosine residue concentration (p < 0.05), and the negative correlation with fructosyl-lysine residues just failed to reach significance (p ¼ 0.052). Multiple linear regression gave a regression model of the MMSE score on 3-nitrotyrosine, fructosyl-lysine and N e -carboxyethyl-lysine residues with p-values of 0.021, 0.031 and 0.052, respectively. These findings indicate that protein glycation, oxidation and nitration adduct residues and free adducts were increased in the CSF of subjects with Alzheimer's disease. A combination of nitration and glycation adduct estimates of CSF may provide an indicator for the diagnosis of Alzheimer's disease.
Annals of The New York Academy of Sciences, 2008
Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreas... more Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreased angiogenesis. In this study, we investigated whether overexpression of glyoxalase 1 to decrease dicarbonyl glycation would prevent the angiogenesis deficit induced by hyperglycemia in vitro. Transfection of human microvascular endothelial cells resulted in a four-fold increase in glyoxalase 1 activity compared with controls. Incubation of human microvascular endothelial cells in model hyperglycemia produced a 32% decrease in formation of tube structures that was prevented by glyoxalase 1 overexpression. We conclude that increased protection against dicarbonyl glycation of endothelial cell protein protects hyperglycemia-induced angiogenesis deficit.
Annals of The New York Academy of Sciences, 2005
Journal of Neurochemistry, 2005
Increased damage to proteins by glycation, oxidation and nitration has been implicated in neurona... more Increased damage to proteins by glycation, oxidation and nitration has been implicated in neuronal cell death leading to Alzheimer's disease (AD). Protein glycation, oxidation and nitration adducts are consequently formed. Quantitative screening of these adducts in CSF may provide a biochemical indicator for the diagnosis of AD. To assess this, we measured 11 glycation adducts, three oxidation adducts and a nitration adduct, determining both protein adduct residues and free adducts, in CSF samples of age-matched normal healthy subjects (n ¼ 18) and subjects with Alzheimer's disease (n ¼ 32). In CSF protein, the concentrations of 3-nitrotyrosine, N e -carboxymethyl-lysine, 3-deoxyglucosone-derived hydroimidazolone and N-formylkynurenine residues were increased in subjects with Alzheimer's disease. In CSF ultrafiltrate, the concentrations of 3-nitrotyrosine, methylglyoxal-derived hydroimidazolone and glyoxal-derived hydroimidazolone free adducts were also increased. The Mini-Mental State Examination (MMSE) score correlated negatively with 3-nitrotyrosine residue concentration (p < 0.05), and the negative correlation with fructosyl-lysine residues just failed to reach significance (p ¼ 0.052). Multiple linear regression gave a regression model of the MMSE score on 3-nitrotyrosine, fructosyl-lysine and N e -carboxyethyl-lysine residues with p-values of 0.021, 0.031 and 0.052, respectively. These findings indicate that protein glycation, oxidation and nitration adduct residues and free adducts were increased in the CSF of subjects with Alzheimer's disease. A combination of nitration and glycation adduct estimates of CSF may provide an indicator for the diagnosis of Alzheimer's disease.
Annals of The New York Academy of Sciences, 2008
Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreas... more Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreased angiogenesis. In this study, we investigated whether overexpression of glyoxalase 1 to decrease dicarbonyl glycation would prevent the angiogenesis deficit induced by hyperglycemia in vitro. Transfection of human microvascular endothelial cells resulted in a four-fold increase in glyoxalase 1 activity compared with controls. Incubation of human microvascular endothelial cells in model hyperglycemia produced a 32% decrease in formation of tube structures that was prevented by glyoxalase 1 overexpression. We conclude that increased protection against dicarbonyl glycation of endothelial cell protein protects hyperglycemia-induced angiogenesis deficit.
Annals of The New York Academy of Sciences, 2005
Societyof Dept. Gas Petroleum of Research Engineers Energy Institute ... Methane Production Chara... more Societyof Dept. Gas Petroleum of Research Engineers Energy Institute ... Methane Production Characteristics for a Deeply Buried Coalbed Reservoir in the San Juan Basin ... Copyright 1984 Society of Petroleum Engineers of AIME This paper waa praaanted at the 1984 SPE/OOE/ ...
Tight gas formations bounded by formations that are not barriers to vertical fracture migration, ... more Tight gas formations bounded by formations that are not barriers to vertical fracture migration, are not amenable to &amp;#39;&amp;#39;successful&amp;#39;&amp;#39; large stimulation treatments by hydraulic fracturing as practiced today. The objective of this paper is to present the preliminary findings of a project sponsored by the Gas Research Institute of Chicago and conducted by Terra Tek, Inc. of Salt Lake City
Abstract Various techniques to partition a system into hardware and software blocks have been pro... more Abstract Various techniques to partition a system into hardware and software blocks have been proposed in the past. Most of these techniques use some form of control flow graphs (CFG) and employ optimization algorithms like simulated annealing or tabu search to ...
Hardware software co-synthesis involves determining the hardware and software architectures for a... more Hardware software co-synthesis involves determining the hardware and software architectures for an application. This process involves selection of processing elements, mapping application parts to those processing elements followed by scheduling. Various heuristic based co-synthesis algorithms have been proposed but many of them are limited by simple architecture and non-pipelined implementations. In this paper we present a new processor allocation and pipelined algorithm which can be used for hardware software co-synthesis. The algorithm iteratively selects processing elements based on performance improvement and then allocates tasks and creates pipeline stages. Task allocation and pipelining processes are interleaved which helps to remove redundant pipeline stages. The algorithm is also applied to an example task graph and results are discussed
Journal of Neurochemistry, 2005
Increased damage to proteins by glycation, oxidation and nitration has been implicated in neurona... more Increased damage to proteins by glycation, oxidation and nitration has been implicated in neuronal cell death leading to Alzheimer's disease (AD). Protein glycation, oxidation and nitration adducts are consequently formed. Quantitative screening of these adducts in CSF may provide a biochemical indicator for the diagnosis of AD. To assess this, we measured 11 glycation adducts, three oxidation adducts and a nitration adduct, determining both protein adduct residues and free adducts, in CSF samples of age-matched normal healthy subjects (n ¼ 18) and subjects with Alzheimer's disease (n ¼ 32). In CSF protein, the concentrations of 3-nitrotyrosine, N e -carboxymethyl-lysine, 3-deoxyglucosone-derived hydroimidazolone and N-formylkynurenine residues were increased in subjects with Alzheimer's disease. In CSF ultrafiltrate, the concentrations of 3-nitrotyrosine, methylglyoxal-derived hydroimidazolone and glyoxal-derived hydroimidazolone free adducts were also increased. The Mini-Mental State Examination (MMSE) score correlated negatively with 3-nitrotyrosine residue concentration (p < 0.05), and the negative correlation with fructosyl-lysine residues just failed to reach significance (p ¼ 0.052). Multiple linear regression gave a regression model of the MMSE score on 3-nitrotyrosine, fructosyl-lysine and N e -carboxyethyl-lysine residues with p-values of 0.021, 0.031 and 0.052, respectively. These findings indicate that protein glycation, oxidation and nitration adduct residues and free adducts were increased in the CSF of subjects with Alzheimer's disease. A combination of nitration and glycation adduct estimates of CSF may provide an indicator for the diagnosis of Alzheimer's disease.
Annals of The New York Academy of Sciences, 2008
Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreas... more Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreased angiogenesis. In this study, we investigated whether overexpression of glyoxalase 1 to decrease dicarbonyl glycation would prevent the angiogenesis deficit induced by hyperglycemia in vitro. Transfection of human microvascular endothelial cells resulted in a four-fold increase in glyoxalase 1 activity compared with controls. Incubation of human microvascular endothelial cells in model hyperglycemia produced a 32% decrease in formation of tube structures that was prevented by glyoxalase 1 overexpression. We conclude that increased protection against dicarbonyl glycation of endothelial cell protein protects hyperglycemia-induced angiogenesis deficit.
Annals of The New York Academy of Sciences, 2005
Journal of Neurochemistry, 2005
Increased damage to proteins by glycation, oxidation and nitration has been implicated in neurona... more Increased damage to proteins by glycation, oxidation and nitration has been implicated in neuronal cell death leading to Alzheimer's disease (AD). Protein glycation, oxidation and nitration adducts are consequently formed. Quantitative screening of these adducts in CSF may provide a biochemical indicator for the diagnosis of AD. To assess this, we measured 11 glycation adducts, three oxidation adducts and a nitration adduct, determining both protein adduct residues and free adducts, in CSF samples of age-matched normal healthy subjects (n ¼ 18) and subjects with Alzheimer's disease (n ¼ 32). In CSF protein, the concentrations of 3-nitrotyrosine, N e -carboxymethyl-lysine, 3-deoxyglucosone-derived hydroimidazolone and N-formylkynurenine residues were increased in subjects with Alzheimer's disease. In CSF ultrafiltrate, the concentrations of 3-nitrotyrosine, methylglyoxal-derived hydroimidazolone and glyoxal-derived hydroimidazolone free adducts were also increased. The Mini-Mental State Examination (MMSE) score correlated negatively with 3-nitrotyrosine residue concentration (p < 0.05), and the negative correlation with fructosyl-lysine residues just failed to reach significance (p ¼ 0.052). Multiple linear regression gave a regression model of the MMSE score on 3-nitrotyrosine, fructosyl-lysine and N e -carboxyethyl-lysine residues with p-values of 0.021, 0.031 and 0.052, respectively. These findings indicate that protein glycation, oxidation and nitration adduct residues and free adducts were increased in the CSF of subjects with Alzheimer's disease. A combination of nitration and glycation adduct estimates of CSF may provide an indicator for the diagnosis of Alzheimer's disease.
Annals of The New York Academy of Sciences, 2008
Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreas... more Dicarbonyl glycation of RGD and GFOGER sites in type IV collagen has been associated with decreased angiogenesis. In this study, we investigated whether overexpression of glyoxalase 1 to decrease dicarbonyl glycation would prevent the angiogenesis deficit induced by hyperglycemia in vitro. Transfection of human microvascular endothelial cells resulted in a four-fold increase in glyoxalase 1 activity compared with controls. Incubation of human microvascular endothelial cells in model hyperglycemia produced a 32% decrease in formation of tube structures that was prevented by glyoxalase 1 overexpression. We conclude that increased protection against dicarbonyl glycation of endothelial cell protein protects hyperglycemia-induced angiogenesis deficit.
Annals of The New York Academy of Sciences, 2005
Societyof Dept. Gas Petroleum of Research Engineers Energy Institute ... Methane Production Chara... more Societyof Dept. Gas Petroleum of Research Engineers Energy Institute ... Methane Production Characteristics for a Deeply Buried Coalbed Reservoir in the San Juan Basin ... Copyright 1984 Society of Petroleum Engineers of AIME This paper waa praaanted at the 1984 SPE/OOE/ ...
Tight gas formations bounded by formations that are not barriers to vertical fracture migration, ... more Tight gas formations bounded by formations that are not barriers to vertical fracture migration, are not amenable to &amp;#39;&amp;#39;successful&amp;#39;&amp;#39; large stimulation treatments by hydraulic fracturing as practiced today. The objective of this paper is to present the preliminary findings of a project sponsored by the Gas Research Institute of Chicago and conducted by Terra Tek, Inc. of Salt Lake City
Abstract Various techniques to partition a system into hardware and software blocks have been pro... more Abstract Various techniques to partition a system into hardware and software blocks have been proposed in the past. Most of these techniques use some form of control flow graphs (CFG) and employ optimization algorithms like simulated annealing or tabu search to ...
Hardware software co-synthesis involves determining the hardware and software architectures for a... more Hardware software co-synthesis involves determining the hardware and software architectures for an application. This process involves selection of processing elements, mapping application parts to those processing elements followed by scheduling. Various heuristic based co-synthesis algorithms have been proposed but many of them are limited by simple architecture and non-pipelined implementations. In this paper we present a new processor allocation and pipelined algorithm which can be used for hardware software co-synthesis. The algorithm iteratively selects processing elements based on performance improvement and then allocates tasks and creates pipeline stages. Task allocation and pipelining processes are interleaved which helps to remove redundant pipeline stages. The algorithm is also applied to an example task graph and results are discussed