The objective of this study was to define the relationship between peroxyl radical-mediated cytot... more The objective of this study was to define the relationship between peroxyl radical-mediated cytotoxicity and lipid, protein and sulfhydryl oxidation using human erythrocytes as the target mammalian cell. We found that incubation of human erythrocytes with the peroxyl radical generator 2,2' azobis (2-amidinopropane) hydrochloride (AAPH) resulted in a time and dose-dependent increase in hemolysis such that at 50 mM AAPH maximum hemolysis was achieved at 120 min. Hemolysis was inhibited by hypoxia and by the addition of certain water soluble free radical scavengers such as 5-aminosalicylic acid (5-ASA), 4-ASA, N-acetyl-5-ASA and dimethyl thiourea. Peroxyl radical-mediated hemolysis did not appear to involve significant peroxidation of erythrocyte lipids nor did they enhance protein oxidation at times preceding hemolysis. Peroxyl radicals did however, significantly reduce by approximately 80% the intracellular levels of GSH and inhibit by approximately 90% erythrocyte Ca(2+)-Mg2+ ATPase activity at times preceding the hemolytic event. Our data as well as others suggest that extracellular oxidants promote the oxidation of intracellular compounds by interacting with certain redox active membrane components. Depletion of intracellular GSH stores using diamide did not result in hemolysis suggesting that oxidation of GSH alone does not promote hemolysis. Taken together, our data suggest that neither GSH oxidation, lipid peroxidation nor protein oxidation alone can account for peroxyl radical-mediated hemolysis. It remains to be determined whether free radical-mediated inactivation of Ca(2+)-Mg2+ ATPase is an important mechanism in this process.
This thesis focuses on twentieth-century poet Frank O\u27Hara and his relationship to painting an... more This thesis focuses on twentieth-century poet Frank O\u27Hara and his relationship to painting and painters in New York in the 1950s. An examination of the concept of ekphrasis functions as a theoretical frame and substantiation for the discussion of O\u27Hara\u27s life and poems. Painters Larry Rivers, Jane Freilicher, and Grace Hartigan had significant relationships with O\u27Hara, both personally and artistically. Michael Goldberg, Norman Bluhm, and Joe Brainard collaborated with him on several projects, each of which are discussed in terms of their combination of verbal and visual elements, of poet and painter working together or in tandem. Another example included in the exploration of O\u27Hara\u27s connection to visual expression is a series of Apollinaire-inspired calligrams. Each element of the discussion helps define the specific context in which O\u27Hara worked, functioning as an example himself of the significant link painting and poetry have historically shared
A 12‐year‐old, 25 kg, intact male St Bernard crossbreed was presented for treatment of a 538 mm u... more A 12‐year‐old, 25 kg, intact male St Bernard crossbreed was presented for treatment of a 538 mm ulcerated tumour on the dorsal tongue. Fine‐needle aspiration cytology revealed a plasmacytoma. The dog staged negative for evidence of local metastatic or systemic disease. Histopathology confirmed the diagnosis. Treatment with one 150 Gy dose of radiation delivered with strontium‐90 plesiotherapy was performed. Side effects were not noted and there was no visible evidence of tumour remaining at 2 months and 1 year after therapy.
The objective of this study was to define the relationship between peroxyl radical-mediated cytot... more The objective of this study was to define the relationship between peroxyl radical-mediated cytotoxicity and lipid, protein and sulfhydryl oxidation using human erythrocytes as the target mammalian cell. We found that incubation of human erythrocytes with the peroxyl radical generator 2,2' azobis (2-amidinopropane) hydrochloride (AAPH) resulted in a time and dose-dependent increase in hemolysis such that at 50 mM AAPH maximum hemolysis was achieved at 120 min. Hemolysis was inhibited by hypoxia and by the addition of certain water soluble free radical scavengers such as 5-aminosalicylic acid (5-ASA), 4-ASA, N-acetyl-5-ASA and dimethyl thiourea. Peroxyl radical-mediated hemolysis did not appear to involve significant peroxidation of erythrocyte lipids nor did they enhance protein oxidation at times preceding hemolysis. Peroxyl radicals did however, significantly reduce by approximately 80% the intracellular levels of GSH and inhibit by approximately 90% erythrocyte Ca(2+)-Mg2+ ATPase activity at times preceding the hemolytic event. Our data as well as others suggest that extracellular oxidants promote the oxidation of intracellular compounds by interacting with certain redox active membrane components. Depletion of intracellular GSH stores using diamide did not result in hemolysis suggesting that oxidation of GSH alone does not promote hemolysis. Taken together, our data suggest that neither GSH oxidation, lipid peroxidation nor protein oxidation alone can account for peroxyl radical-mediated hemolysis. It remains to be determined whether free radical-mediated inactivation of Ca(2+)-Mg2+ ATPase is an important mechanism in this process.
Background/Aims: We previously reported that patients with chronic kidney disease (CKD) receiving... more Background/Aims: We previously reported that patients with chronic kidney disease (CKD) receiving warfarin therapy and whose international normalized ratio increases to >3.0 may develop acute kidney injury (AKI) as a result of glomerular hemorrhage and formation of obstructive red blood cell (RBC) casts. We named this condition warfarin-related nephropathy (WRN). We also previously reported that acute excessive anticoagulation with brodifacoum (superwarfarin) induces AKI in 5/6 nephrectomy (5/6NE) rats. Limitations of the brodifacoum model precluded a careful assessment of dose-response relationships. Methods: Warfarin treatment was used in 5/6NE. Results: Herein we report that warfarin treatment of 5/6NE rats resulted in a dose-dependent increase in serum creatinine (SC). The increase in SC following warfarin treatment was greater at 3 and 19 weeks after the ablative surgery, than that observed 8 weeks after the ablative surgery. The SC increase was correlated with the prothromb...
Submarine Mass Movements and Their Consequences, 2011
The continental margin of the northern South China Sea is a NE-SW trending passive continental ma... more The continental margin of the northern South China Sea is a NE-SW trending passive continental margin. Mapping of the continental slope from short offset processed 3D seismic across the offshore Pearl River Mouth Basin shows the margin to be characterised by a canyoned morphology from 600 to 1,500 m water depth. Shallower than these depths the slope is undisturbed while at greater depths there is a return to a smooth base of slope morphology with broad runout channels reflecting mass transport deposition fed from the canyons. The canyons are typically ∼1 km wide and up to 20 km long, steep sided and asymmetric with a higher slope angle along their eastern margins. Comparatively, the western margins show increased evidence of slumping and slope failure. The intercanyon ridges exhibit arcuate slump features. Mapping of the base Pleistocene shows this slumping has resulted in removal of Quaternary sediment along the intercanyon ridges. Mass transport deposits are also identified along the lower slope. The erosion of these canyons is considered to be related to the internal waves generated from the strong Kuroshio Current crossing the shallow bathymetry of the Luzon Strait into the South China Sea resulting in internal waves interacting with the slope below 600 m. Understanding the dynamics of canyon systems such as these is essential for determining risk to deep sea exploration infrastructure.
The objective of this study was to define the relationship between peroxyl radical-mediated cytot... more The objective of this study was to define the relationship between peroxyl radical-mediated cytotoxicity and lipid, protein and sulfhydryl oxidation using human erythrocytes as the target mammalian cell. We found that incubation of human erythrocytes with the peroxyl radical generator 2,2' azobis (2-amidinopropane) hydrochloride (AAPH) resulted in a time and dose-dependent increase in hemolysis such that at 50 mM AAPH maximum hemolysis was achieved at 120 min. Hemolysis was inhibited by hypoxia and by the addition of certain water soluble free radical scavengers such as 5-aminosalicylic acid (5-ASA), 4-ASA, N-acetyl-5-ASA and dimethyl thiourea. Peroxyl radical-mediated hemolysis did not appear to involve significant peroxidation of erythrocyte lipids nor did they enhance protein oxidation at times preceding hemolysis. Peroxyl radicals did however, significantly reduce by approximately 80% the intracellular levels of GSH and inhibit by approximately 90% erythrocyte Ca(2+)-Mg2+ ATPase activity at times preceding the hemolytic event. Our data as well as others suggest that extracellular oxidants promote the oxidation of intracellular compounds by interacting with certain redox active membrane components. Depletion of intracellular GSH stores using diamide did not result in hemolysis suggesting that oxidation of GSH alone does not promote hemolysis. Taken together, our data suggest that neither GSH oxidation, lipid peroxidation nor protein oxidation alone can account for peroxyl radical-mediated hemolysis. It remains to be determined whether free radical-mediated inactivation of Ca(2+)-Mg2+ ATPase is an important mechanism in this process.
This thesis focuses on twentieth-century poet Frank O\u27Hara and his relationship to painting an... more This thesis focuses on twentieth-century poet Frank O\u27Hara and his relationship to painting and painters in New York in the 1950s. An examination of the concept of ekphrasis functions as a theoretical frame and substantiation for the discussion of O\u27Hara\u27s life and poems. Painters Larry Rivers, Jane Freilicher, and Grace Hartigan had significant relationships with O\u27Hara, both personally and artistically. Michael Goldberg, Norman Bluhm, and Joe Brainard collaborated with him on several projects, each of which are discussed in terms of their combination of verbal and visual elements, of poet and painter working together or in tandem. Another example included in the exploration of O\u27Hara\u27s connection to visual expression is a series of Apollinaire-inspired calligrams. Each element of the discussion helps define the specific context in which O\u27Hara worked, functioning as an example himself of the significant link painting and poetry have historically shared
A 12‐year‐old, 25 kg, intact male St Bernard crossbreed was presented for treatment of a 538 mm u... more A 12‐year‐old, 25 kg, intact male St Bernard crossbreed was presented for treatment of a 538 mm ulcerated tumour on the dorsal tongue. Fine‐needle aspiration cytology revealed a plasmacytoma. The dog staged negative for evidence of local metastatic or systemic disease. Histopathology confirmed the diagnosis. Treatment with one 150 Gy dose of radiation delivered with strontium‐90 plesiotherapy was performed. Side effects were not noted and there was no visible evidence of tumour remaining at 2 months and 1 year after therapy.
The objective of this study was to define the relationship between peroxyl radical-mediated cytot... more The objective of this study was to define the relationship between peroxyl radical-mediated cytotoxicity and lipid, protein and sulfhydryl oxidation using human erythrocytes as the target mammalian cell. We found that incubation of human erythrocytes with the peroxyl radical generator 2,2' azobis (2-amidinopropane) hydrochloride (AAPH) resulted in a time and dose-dependent increase in hemolysis such that at 50 mM AAPH maximum hemolysis was achieved at 120 min. Hemolysis was inhibited by hypoxia and by the addition of certain water soluble free radical scavengers such as 5-aminosalicylic acid (5-ASA), 4-ASA, N-acetyl-5-ASA and dimethyl thiourea. Peroxyl radical-mediated hemolysis did not appear to involve significant peroxidation of erythrocyte lipids nor did they enhance protein oxidation at times preceding hemolysis. Peroxyl radicals did however, significantly reduce by approximately 80% the intracellular levels of GSH and inhibit by approximately 90% erythrocyte Ca(2+)-Mg2+ ATPase activity at times preceding the hemolytic event. Our data as well as others suggest that extracellular oxidants promote the oxidation of intracellular compounds by interacting with certain redox active membrane components. Depletion of intracellular GSH stores using diamide did not result in hemolysis suggesting that oxidation of GSH alone does not promote hemolysis. Taken together, our data suggest that neither GSH oxidation, lipid peroxidation nor protein oxidation alone can account for peroxyl radical-mediated hemolysis. It remains to be determined whether free radical-mediated inactivation of Ca(2+)-Mg2+ ATPase is an important mechanism in this process.
Background/Aims: We previously reported that patients with chronic kidney disease (CKD) receiving... more Background/Aims: We previously reported that patients with chronic kidney disease (CKD) receiving warfarin therapy and whose international normalized ratio increases to >3.0 may develop acute kidney injury (AKI) as a result of glomerular hemorrhage and formation of obstructive red blood cell (RBC) casts. We named this condition warfarin-related nephropathy (WRN). We also previously reported that acute excessive anticoagulation with brodifacoum (superwarfarin) induces AKI in 5/6 nephrectomy (5/6NE) rats. Limitations of the brodifacoum model precluded a careful assessment of dose-response relationships. Methods: Warfarin treatment was used in 5/6NE. Results: Herein we report that warfarin treatment of 5/6NE rats resulted in a dose-dependent increase in serum creatinine (SC). The increase in SC following warfarin treatment was greater at 3 and 19 weeks after the ablative surgery, than that observed 8 weeks after the ablative surgery. The SC increase was correlated with the prothromb...
Submarine Mass Movements and Their Consequences, 2011
The continental margin of the northern South China Sea is a NE-SW trending passive continental ma... more The continental margin of the northern South China Sea is a NE-SW trending passive continental margin. Mapping of the continental slope from short offset processed 3D seismic across the offshore Pearl River Mouth Basin shows the margin to be characterised by a canyoned morphology from 600 to 1,500 m water depth. Shallower than these depths the slope is undisturbed while at greater depths there is a return to a smooth base of slope morphology with broad runout channels reflecting mass transport deposition fed from the canyons. The canyons are typically ∼1 km wide and up to 20 km long, steep sided and asymmetric with a higher slope angle along their eastern margins. Comparatively, the western margins show increased evidence of slumping and slope failure. The intercanyon ridges exhibit arcuate slump features. Mapping of the base Pleistocene shows this slumping has resulted in removal of Quaternary sediment along the intercanyon ridges. Mass transport deposits are also identified along the lower slope. The erosion of these canyons is considered to be related to the internal waves generated from the strong Kuroshio Current crossing the shallow bathymetry of the Luzon Strait into the South China Sea resulting in internal waves interacting with the slope below 600 m. Understanding the dynamics of canyon systems such as these is essential for determining risk to deep sea exploration infrastructure.
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