martin valenzuela | Pontificia Universidad Catolica del Peru (original) (raw)
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Digestive Diseases and Sciences, 1994
Gastric emptying of a solid meal and of 10 indigestible radiopaque solids was measured with scint... more Gastric emptying of a solid meal and of 10 indigestible radiopaque solids was measured with scintigraphic and radiological techniques in 50 healthy volunteers (controls), 41 patients with insulin-dependent diabetes mellitus, and 50 patients with functional dyspepsia. Gastroparesis was found in 51% of our diabetic patients and 74% of our patients with dyspepsia. The values ofT lag,T 1/2 and the percentage of isotope remaining in the stomach at 105 min were 14.9 min, 59.4 min and 25.3% in control subjects; 21.4 min, 88.1 min, and 46.9% in diabetic patients (P<0.05 vs the control group); and 23.2 min, 114.6 min, and 58.7% in dyspeptic patients (P<0.05 vs the control group). Whereas all healthy volunteers emptied all 10 indigestible solids in less than 4 hr, only 51% and 32% of diabetics and dyspeptics, respectively, achieved this emptying time (P<0.01). Their respective values ofT 1/2 were 81 min, 212 min, and 203 min (P<0.01 for diabetics and dyspeptics vs controls). We found no correlation between the findings for gastric emptying of digestible and indigestible solids. We conclude that gastroparesis affecting digestive and interdigestive motility is present in a high percentage of diabetics and functional dyspeptics and that conscientious evaluation of gastroparesis in both groups requires studies designed specifically to characterize each type of motility.
Journal of Cellular Biochemistry, 2005
3-nitrotyrosine (NO 2 -Tyr) is thought to be a specific marker of cell injury during oxidative da... more 3-nitrotyrosine (NO 2 -Tyr) is thought to be a specific marker of cell injury during oxidative damage. We have evaluated the role of poly(ADP-ribose)polymerase-1 (PARP-1) in protein nitration after treatment of immortalized fibroblasts parp-1þ/þ and parp-1À/À with the alkylating agent 2 0 -methyl-2 0 -nitroso-urea (MNU). Both cell lines showed increased iNOS expression following MNU treatment in parallel with a selective induction of tyrosine nitration of different proteins. PARP-1 deficient cells displayed a delayed iNOS accumulation, reduced number of nitrated proteins, and a lower global nitrotyrosine ''footprint.'' We have identified the mitochondrial compartment as the major site of oxidative stress during DNA damage, being MnSOD one of the NO 2 -Tyr-modified proteins, but not in parp-1À/À cells. These results suggest that NO-derived injury can be modulated by proteins involved in the response to genotoxic damage, such as PARP-1, and may account for the limited oxidative injury in parp-1 knockout mice during carcinogenesis and inflammation.
Digestive Diseases and Sciences, 1994
Gastric emptying of a solid meal and of 10 indigestible radiopaque solids was measured with scint... more Gastric emptying of a solid meal and of 10 indigestible radiopaque solids was measured with scintigraphic and radiological techniques in 50 healthy volunteers (controls), 41 patients with insulin-dependent diabetes mellitus, and 50 patients with functional dyspepsia. Gastroparesis was found in 51% of our diabetic patients and 74% of our patients with dyspepsia. The values ofT lag,T 1/2 and the percentage of isotope remaining in the stomach at 105 min were 14.9 min, 59.4 min and 25.3% in control subjects; 21.4 min, 88.1 min, and 46.9% in diabetic patients (P<0.05 vs the control group); and 23.2 min, 114.6 min, and 58.7% in dyspeptic patients (P<0.05 vs the control group). Whereas all healthy volunteers emptied all 10 indigestible solids in less than 4 hr, only 51% and 32% of diabetics and dyspeptics, respectively, achieved this emptying time (P<0.01). Their respective values ofT 1/2 were 81 min, 212 min, and 203 min (P<0.01 for diabetics and dyspeptics vs controls). We found no correlation between the findings for gastric emptying of digestible and indigestible solids. We conclude that gastroparesis affecting digestive and interdigestive motility is present in a high percentage of diabetics and functional dyspeptics and that conscientious evaluation of gastroparesis in both groups requires studies designed specifically to characterize each type of motility.
Journal of Cellular Biochemistry, 2005
3-nitrotyrosine (NO 2 -Tyr) is thought to be a specific marker of cell injury during oxidative da... more 3-nitrotyrosine (NO 2 -Tyr) is thought to be a specific marker of cell injury during oxidative damage. We have evaluated the role of poly(ADP-ribose)polymerase-1 (PARP-1) in protein nitration after treatment of immortalized fibroblasts parp-1þ/þ and parp-1À/À with the alkylating agent 2 0 -methyl-2 0 -nitroso-urea (MNU). Both cell lines showed increased iNOS expression following MNU treatment in parallel with a selective induction of tyrosine nitration of different proteins. PARP-1 deficient cells displayed a delayed iNOS accumulation, reduced number of nitrated proteins, and a lower global nitrotyrosine ''footprint.'' We have identified the mitochondrial compartment as the major site of oxidative stress during DNA damage, being MnSOD one of the NO 2 -Tyr-modified proteins, but not in parp-1À/À cells. These results suggest that NO-derived injury can be modulated by proteins involved in the response to genotoxic damage, such as PARP-1, and may account for the limited oxidative injury in parp-1 knockout mice during carcinogenesis and inflammation.