The isolated stomach of rats was vascularly perfused to measure the secretion of gastrin, somatos... more The isolated stomach of rats was vascularly perfused to measure the secretion of gastrin, somatostatin (SLI) and bombesin-like immunoreactivity (BLI). The gastric lumen was perfused with saline pH 7 or pH 2, and electrical vagal stimulation was performed with 1 ms, 10 V and 2, 5 or 10 Hz, respectively. Atropine was added in concentrations of 10(-9) or 10(-7) M to evaluate the role of cholinergic mechanisms. In control experiments, vagal stimulation during luminal pH 2 elicited a significant increase of BLI secretion only at 10 Hz but not at 2 and 5 Hz. Somatostatin release was inhibited independent of the stimulation frequency employed. Gastrin secretion at 2 Hz was twice the secretion rates observed at 5 and 10 Hz, respectively. At luminal pH 7 BLI rose significantly at 5 and 10 Hz. SLI secretion was decreased by all frequencies. Gastrin secretion at 2 and 5 Hz was twice as high as during stimulation with 10 Hz. Atropine at doses of 10(-9), 10(-8), 10(-7) and 10(-6) M had no effect...
NATO Science for Peace and Security Series A: Chemistry and Biology, 2009
Sulfur mustard (SM) is a strong vesicant and a bifunctional alkylating agent targeting mainly nuc... more Sulfur mustard (SM) is a strong vesicant and a bifunctional alkylating agent targeting mainly nuclear DNA. By introducing several modifications, mostly in guanine and adenine, it severely damages the DNA, and consequently the cell. Because of its bifunctionality, it also creates crosslinks between guanine bases of the same or a different strand (17% of total alkylation). The high capability of
The chemical warfare agent sulfur mustard (SM) is a strong alkylating agent that leads to erythem... more The chemical warfare agent sulfur mustard (SM) is a strong alkylating agent that leads to erythema and ulceration of the human skin several hours after exposure. Although SM has been intensively investigated, the cellular mechanisms leading to cell damage remain unclear. Apoptosis, necrosis and direct cell damage are discussed. In this study we investigated apoptotic cell death in pulmonary A549 cells exposed to SM (30-1000 microM, 30 min). 24 h after SM exposure DNA breaks were stained with the TUNEL method. Additionally, A549 cells were lysed and cellular protein was transferred to SDS page and blotted. Whole PARP as well as PARP cleavage into the p89 fragment, an indicator of apoptosis, were detected by specific antibodies. SM concentration dependent increase in TUNEL positive cells and PARP cleavage showed that SM is an inducer of apoptosis. It has been previously suggested that AChE is activated during apoptotic processes and may be involved in apoptosis regulation. Therefore, ...
Sulfur mustard (SM; bis(2-chloroethyl)sulphide; HD) is a blister inducing agent causing DNA damag... more Sulfur mustard (SM; bis(2-chloroethyl)sulphide; HD) is a blister inducing agent causing DNA damage and subsequently, cell death, mostly by apoptosis in basal keratinocytes. Despite intensive investigations on the cellular mechanism, there are, as of now, no causal therapeutics to prevent or antagonize SM-related damage to cells and tissues. In order to develop treatment strategies against vesication, it is important to distinguish apoptosis from necrosis in SM treated human keratinocytes. DNA fragmentation is a hallmark of apoptosis and regulated by a cascade of enzymes (endonucleases, DNase I, NUC 18), which finally cut the chromatin into specific formations of 180-200 base pairs, the nucleosomes. A feasible way to monitor apoptosis is the detection of nucleosomes by means of the Cell Death Detection ELISA(plus) (CDDE). In contrast, during necrosis DNA fragmentation is at random and delivers larger fragments, which therefore are significantly less in number and predominantly occur in cell culture supernatant. To monitor necrosis, we measured the release of intracellular adenylate kinase (AK) into cell culture supernatant by means of the ToxiLight Bioluminescence Assay (TL). With combination of the Cell Death Detection ELISA(plus) and the ToxiLight Bioluminescence Assay, we acquired more comprehensive information on cell survival and mechanisms of cell death, following an SM exposure. To validate the assay we tested common apoptosis- and necrosis-inducing agents like SM 300 microM for 30 min, Lewisite (L) 60 microM for 5 min and Triton X-100 0.1%. The results show that it is possible to differentiate between the two modes of cell death and to quantify their extent. This assay is highly effective in quantifying apoptosis and necrosis caused by cytotoxic agents and in estimating protective effects of potential active pharmaceutical ingredients.
Whilst the acute effects of sulfur mustard have been relatively well characterised, the chronic e... more Whilst the acute effects of sulfur mustard have been relatively well characterised, the chronic effects of short term but significant exposures are still evolving. The approximately 30,000 Iranian victims of CW exposure from the 1980 to 1988 Iran-Iraq war who are currently being followed form a key population who are now 20 years post-exposure. The key chronic findings in this population reflect the common acute effects of sulfur mustard, and are related to the skin, eye and respiratory system. Excluding pruritus, skin changes appear to settle. Eye symptoms are slowly progressive, however a severe, rapid onset form of keratitis is seen to develop in a number of patients after a latent period of 15-20 years. The respiratory tract also shows progressive deterioration, with bronchiolitis obliterans now being considered the main pathological feature of "mustard lung". In addition, there are other potential effects of sulfur mustard exposure which become evident only in the longer term and which are being investigated, including the development of cancer, immunological and neuropsychiatric changes, and reproductive effects. Finally, a chronic effect of sulfur mustard exposure that is now becoming apparent is the wider long-term social and economic effects of these illnesses on individuals and their families.
Sulfur mustard (SM) is a strong alkylating agent, which produces subepidermal blisters, erythema ... more Sulfur mustard (SM) is a strong alkylating agent, which produces subepidermal blisters, erythema and inflammation after skin contact. Despite the well-described SM-induced gross and histopathological changes, the exact underlying molecular mechanisms of these events are still a matter of research. As part of an international effort to elucidate the components of cellular signal transduction pathways, a large body of data has been accumulated in the last decade of SM research, revealing deeper insight into SM-induced inflammation, DNA damage response, cell death signaling, and wound healing. SM potentially alkylates nearly every constituent of the cell, leading to impaired cellular functions. However, SM-induced DNA alkylation has been identified as a major trigger of apoptosis. This includes monofunctional SM-DNA adducts as well as DNA crosslinks. As a consequence, DNA replication is blocked, which leads to cell cycle arrest and DNA single and double strand breaks. The SM-induced DNA damage results in poly(ADP-ribose) polymerase (PARP) activation. High SM concentrations induce PARP overactivation, thus depleting cellular NAD(+) and ATP levels, which in consequence results in necrotic cell death. Mild PARP activation does not disturb cellular energy levels and allows apoptotic cell death or recovery to occur. SM-induced apoptosis has been linked both to the extrinsic (death receptor, Fas) and intrinsic (mitochondrial) pathway. Additionally, SM upregulates many inflammatory mediators including interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha) and others. Recently, several investigators linked NF-kappaB activation to this inflammatory response. This review briefly summarizes the skin toxicity of SM, its proposed toxicodynamic actions and strategies for the development of improved medical therapy.
The isolated stomach of rats was vascularly perfused to measure the secretion of gastrin, somatos... more The isolated stomach of rats was vascularly perfused to measure the secretion of gastrin, somatostatin (SLI) and bombesin-like immunoreactivity (BLI). The gastric lumen was perfused with saline pH 7 or pH 2, and electrical vagal stimulation was performed with 1 ms, 10 V and 2, 5 or 10 Hz, respectively. Atropine was added in concentrations of 10(-9) or 10(-7) M to evaluate the role of cholinergic mechanisms. In control experiments, vagal stimulation during luminal pH 2 elicited a significant increase of BLI secretion only at 10 Hz but not at 2 and 5 Hz. Somatostatin release was inhibited independent of the stimulation frequency employed. Gastrin secretion at 2 Hz was twice the secretion rates observed at 5 and 10 Hz, respectively. At luminal pH 7 BLI rose significantly at 5 and 10 Hz. SLI secretion was decreased by all frequencies. Gastrin secretion at 2 and 5 Hz was twice as high as during stimulation with 10 Hz. Atropine at doses of 10(-9), 10(-8), 10(-7) and 10(-6) M had no effect...
NATO Science for Peace and Security Series A: Chemistry and Biology, 2009
Sulfur mustard (SM) is a strong vesicant and a bifunctional alkylating agent targeting mainly nuc... more Sulfur mustard (SM) is a strong vesicant and a bifunctional alkylating agent targeting mainly nuclear DNA. By introducing several modifications, mostly in guanine and adenine, it severely damages the DNA, and consequently the cell. Because of its bifunctionality, it also creates crosslinks between guanine bases of the same or a different strand (17% of total alkylation). The high capability of
The chemical warfare agent sulfur mustard (SM) is a strong alkylating agent that leads to erythem... more The chemical warfare agent sulfur mustard (SM) is a strong alkylating agent that leads to erythema and ulceration of the human skin several hours after exposure. Although SM has been intensively investigated, the cellular mechanisms leading to cell damage remain unclear. Apoptosis, necrosis and direct cell damage are discussed. In this study we investigated apoptotic cell death in pulmonary A549 cells exposed to SM (30-1000 microM, 30 min). 24 h after SM exposure DNA breaks were stained with the TUNEL method. Additionally, A549 cells were lysed and cellular protein was transferred to SDS page and blotted. Whole PARP as well as PARP cleavage into the p89 fragment, an indicator of apoptosis, were detected by specific antibodies. SM concentration dependent increase in TUNEL positive cells and PARP cleavage showed that SM is an inducer of apoptosis. It has been previously suggested that AChE is activated during apoptotic processes and may be involved in apoptosis regulation. Therefore, ...
Sulfur mustard (SM; bis(2-chloroethyl)sulphide; HD) is a blister inducing agent causing DNA damag... more Sulfur mustard (SM; bis(2-chloroethyl)sulphide; HD) is a blister inducing agent causing DNA damage and subsequently, cell death, mostly by apoptosis in basal keratinocytes. Despite intensive investigations on the cellular mechanism, there are, as of now, no causal therapeutics to prevent or antagonize SM-related damage to cells and tissues. In order to develop treatment strategies against vesication, it is important to distinguish apoptosis from necrosis in SM treated human keratinocytes. DNA fragmentation is a hallmark of apoptosis and regulated by a cascade of enzymes (endonucleases, DNase I, NUC 18), which finally cut the chromatin into specific formations of 180-200 base pairs, the nucleosomes. A feasible way to monitor apoptosis is the detection of nucleosomes by means of the Cell Death Detection ELISA(plus) (CDDE). In contrast, during necrosis DNA fragmentation is at random and delivers larger fragments, which therefore are significantly less in number and predominantly occur in cell culture supernatant. To monitor necrosis, we measured the release of intracellular adenylate kinase (AK) into cell culture supernatant by means of the ToxiLight Bioluminescence Assay (TL). With combination of the Cell Death Detection ELISA(plus) and the ToxiLight Bioluminescence Assay, we acquired more comprehensive information on cell survival and mechanisms of cell death, following an SM exposure. To validate the assay we tested common apoptosis- and necrosis-inducing agents like SM 300 microM for 30 min, Lewisite (L) 60 microM for 5 min and Triton X-100 0.1%. The results show that it is possible to differentiate between the two modes of cell death and to quantify their extent. This assay is highly effective in quantifying apoptosis and necrosis caused by cytotoxic agents and in estimating protective effects of potential active pharmaceutical ingredients.
Whilst the acute effects of sulfur mustard have been relatively well characterised, the chronic e... more Whilst the acute effects of sulfur mustard have been relatively well characterised, the chronic effects of short term but significant exposures are still evolving. The approximately 30,000 Iranian victims of CW exposure from the 1980 to 1988 Iran-Iraq war who are currently being followed form a key population who are now 20 years post-exposure. The key chronic findings in this population reflect the common acute effects of sulfur mustard, and are related to the skin, eye and respiratory system. Excluding pruritus, skin changes appear to settle. Eye symptoms are slowly progressive, however a severe, rapid onset form of keratitis is seen to develop in a number of patients after a latent period of 15-20 years. The respiratory tract also shows progressive deterioration, with bronchiolitis obliterans now being considered the main pathological feature of "mustard lung". In addition, there are other potential effects of sulfur mustard exposure which become evident only in the longer term and which are being investigated, including the development of cancer, immunological and neuropsychiatric changes, and reproductive effects. Finally, a chronic effect of sulfur mustard exposure that is now becoming apparent is the wider long-term social and economic effects of these illnesses on individuals and their families.
Sulfur mustard (SM) is a strong alkylating agent, which produces subepidermal blisters, erythema ... more Sulfur mustard (SM) is a strong alkylating agent, which produces subepidermal blisters, erythema and inflammation after skin contact. Despite the well-described SM-induced gross and histopathological changes, the exact underlying molecular mechanisms of these events are still a matter of research. As part of an international effort to elucidate the components of cellular signal transduction pathways, a large body of data has been accumulated in the last decade of SM research, revealing deeper insight into SM-induced inflammation, DNA damage response, cell death signaling, and wound healing. SM potentially alkylates nearly every constituent of the cell, leading to impaired cellular functions. However, SM-induced DNA alkylation has been identified as a major trigger of apoptosis. This includes monofunctional SM-DNA adducts as well as DNA crosslinks. As a consequence, DNA replication is blocked, which leads to cell cycle arrest and DNA single and double strand breaks. The SM-induced DNA damage results in poly(ADP-ribose) polymerase (PARP) activation. High SM concentrations induce PARP overactivation, thus depleting cellular NAD(+) and ATP levels, which in consequence results in necrotic cell death. Mild PARP activation does not disturb cellular energy levels and allows apoptotic cell death or recovery to occur. SM-induced apoptosis has been linked both to the extrinsic (death receptor, Fas) and intrinsic (mitochondrial) pathway. Additionally, SM upregulates many inflammatory mediators including interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha) and others. Recently, several investigators linked NF-kappaB activation to this inflammatory response. This review briefly summarizes the skin toxicity of SM, its proposed toxicodynamic actions and strategies for the development of improved medical therapy.
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