AIM: To investigate the effect of ascorbic acid (AA) dietary supplementation on myenteric neurons and epithelial cell proliferation of the jejunum of adult rats with chronic diabetes mellitus. METHODS: Thirty rats at ...AIM: To investigate the effect of ascorbic acid (AA) dietary supplementation on myenteric neurons and epithelial cell proliferation of the jejunum of adult rats with chronic diabetes mellitus. METHODS: Thirty rats at 90 d of age were divided into three groups: Non-diabetic, diabetic and diabetic treated with AA (DA) (1 g/L). After 120 d of treatment with AA the animals were killed. The myenteric neurons were stained for myosin-V and analyzed quantitatively in an area of 11.2 mm2/animal. We further measured the cellular area of 500 neurons per group. We also determined the metaphasic index (MI) of the jejunum mucosa layer of about 2500 cells in the intestinal crypts, as well as the dimensions of 30 villi and 30 crypts/animal. The data area was analyzed using the Olympus BX40 microscope. RESULTS: There was an increase of 14% in the neuronal density (792.6 ± 46.52 vs 680.6 ± 30.27) and 4.4% in the cellular area (303.4 ± 5.19 vs 291.1 ± 6.0) respectively of the diabetic group treated with AA when compared to control diabetic animals. There were no signifi cant differences in MI parameters, villi height or crypt depths among the groups.CONCLUSION: Supplementation with AA in the diabetic animal promoted moderate neuroprotection. There was no observation of alteration of the cellular proliferation of the jejunum mucosa layer of rats with chronic diabetes mellitus with or without supplementation with AA.展开更多
AIM;Oxidative stress participates in the cell carcinogenesis by inducing DNA mutations.Our aim was to assess whether ascorbic acid,an antioxidant,could have a role in preventing ROS(Reactive Oxygen Species)generation ...AIM;Oxidative stress participates in the cell carcinogenesis by inducing DNA mutations.Our aim was to assess whether ascorbic acid,an antioxidant,could have a role in preventing ROS(Reactive Oxygen Species)generation in experimental gastric carcinoma in a rat model. METHODS:Experimental gastric cancer was induced in twelve Wistar male rats(weighting 250-350 g)by profound duodeno-gastric reflux throught split gastrojenunostomy.The rats were allocated to the following groups:Group Ⅰ(n=6) was the control;Group Ⅱ(n=6)which was mantained with daily intake of tape water with Vitamin C(30 mg/Kg).After 6 or 12 months,samples of gastric tumor or non tumor mucosa were taken from the anastomosis of both groups. Oxidative stress was measured by superoxide quantification through lucigenin-amplified chemiluminescence base and by staining with Nitrobluetetrazolium.The histopathologic confirmation of adenocarcinoma was made by eosin- hemathoxilin method. RESULTS:The intestinal type of gastric adenocarcinoma was microscopically identified in all animals of group Ⅰ whereas only 3 rats of group Ⅱ showed an adenocarcinoma without macroscopic evidence of them.The cancers were located in the anastomosis in all cases.Basal luminescence from tumor gastric tissue generated 38.4±6.8 count per minute/mg/×10~6(mean±SD)and 14.9±4.0 count per minute/mg/×10~6,respectively,in group Ⅰ and Ⅱ animals(P <0.05).The Nitrobluetetrazolium method showed intense staining in tumor tissues but not in non neoplasic mucosa. CONCLUSION:Experimental gastric tumors seem to produce more reactive oxygen species than non neoplasic gastric tissue.The reduction of oxidative stress and gastric tumor incidence in rats were induced by the intake of ascorbic acid.Therefore,it may have a role in the prevention of gastric carcinoma. Oliveira CPMS Kassab P Lopasso FP Souza HP Janiszewski M Laurindo FRM Iriya K Laudanna AA.Protective effect of ascorbic acid in experimental gastric cancer:reduction of oxidative stress.World J Gastroenterol 2003;9(3):446-448 http://www.wjgnet.com/1007-9327/9/446.htm展开更多
Different amounts of vitamin C were added to diets fed to juveniles （2.5＋0.15 g） of sea cucumber Apostichopus japonicus （Selenka） in an attempt to reduce the stress response of specimens exposed to nitrite stress...Different amounts of vitamin C were added to diets fed to juveniles （2.5＋0.15 g） of sea cucumber Apostichopus japonicus （Selenka） in an attempt to reduce the stress response of specimens exposed to nitrite stress. A commercial feed was used as the control diet and three experimental diets were made by supplementing 1 000, 1 500, or 2 000 mg vitamin C/kg diet to control diet separately in a 45-day experiment. Sea cucumbers were exposed to three different levels （0.5, 1.0, and 1.5 mg/L） of nitrite stress for 4, 8, and 12 h at four time intervals （0, 15, 30, and 45 d）. Growth of the animals was recorded during the experiment. Reactive oxygen species （ROS） （i.e. hydroxyl free radical （-OH）, malondialdehyde （MDA） and total antioxidant capacity （T-AOC）） and antioxidant enzyme activities （i.e., superoxide dismutase （SOD） and eatalase （CAT）） were measured. Response surface methodology （RSM） was used to analyze the effect of multiple factors on ROS indices and enzyme activities. Weight gain （WG） and special growth rate （SGR） of vitamin C supplementation groups were significantly higher than those of control group （P〈0.05）. The levels of-OH and MDA increased under exposure time extending and nitrite concentration increasing, whereas T-AOC level decreased. SOD and CAT activities increased at 4 h and 8 h and decreased at 12 h. During the days in which the animal consumed experimental diets, the levels of-OH and MDA decreased and that of T-AOC increased. This result suggests that diets containing vitamin C could reduce the nitrite stress response in the animals and increase their antioxidant capacity. The multifactor regression equation of growth performance, ROS indices, and duration of feeding results suggest that vitamin C supplementation of 1 400-2 000 mg/kg diet for 29-35 days could reduce effectively the effects of nitrite exposure.展开更多
The synthesis and catalytic properties of copper nanoparticles（Cunps） were reported using L-ascorbic acid as reducing and capping agent in aqueous medium. The effect of different concentrations of L-ascorbic acid on...The synthesis and catalytic properties of copper nanoparticles（Cunps） were reported using L-ascorbic acid as reducing and capping agent in aqueous medium. The effect of different concentrations of L-ascorbic acid on the particle size of Cunps was investigated. The synthesized Cunps were characterized by UV-Visible spectrophotometer, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and Fourier transform infrared（FTIR） spectrophotometer. The result indicates that the size of copper nanoparticles decreases with the increase in concentration of L-ascorbic acid. L-Ascorbic acid plays an important role to protect the copper nanoparticles from oxidation and agglomeration which helps nanoparticles to get better stability for the application. The synthesized Cunps show excellent catalytic activity in the oxidation of serine（Ser） by peroxomonosulphate（PMS）. The catalytic activity of Cunps increases with the decrease in size of Cunps. The Cunps are expected to be suitable alternative and play an imperative role in the fields of catalysis and environmental remediation.展开更多
Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphi...Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphite （Na2S205） salt concentration （0%-2%） on vitamin C content, hardness （texture）, microbial count and color intensity of green pepper （Capsicum sinensis） during canning. Blanching, processing time and sodium metabisulphite （Na2S205） salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant （P 〈 0.05） interactions were noted between all the factors with high regression coefficients （78.7%-97.0%）. Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were： blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.展开更多
The tight junction disorder plays an important role in the pathological process of many chronic diseases, and is becoming a major concern for the clinical application of metal drugs, i.e. anti-diabetic vanadium compou...The tight junction disorder plays an important role in the pathological process of many chronic diseases, and is becoming a major concern for the clinical application of metal drugs, i.e. anti-diabetic vanadium compounds. The development of novel tight junction protecting agents has thus been a major research focus. Since oxidative stress is the primary cause for vanadium toxicity, the present work tested the protective effects of zinc gluconate （Zn2＋） alone and when combined with vitamin C （VC） on the vanadium compound （VO（acac）z.）-mediated paracellular leakage of MDCK cells. The experimental results showed that VO（acac）2_ treatment significantly increased the paracellular permeability of MDCK monolayer. Zn2＋ alone showed no protective effects and VC ameliorated tight junction leakage of MDCK cells when given in the basal chamber. Interestingly, unilateral treatment with the combination of Zn2＋ and VC effectively prevented the increase of paracellular permeability. In addition, the combination of zinc and VC down-regulated the levels of reactive oxygen species in both the control and VO（acac）2-treated MDCK cells and caused the elevation of intracellular Ca2＋; both effects were beneficial for the maintenance of integrity of intercellular tight junction. Our results provided a simple but very effective method of preventing the metal toxicity for clinical aoNication of anti-diabetic vanadium compounds.展开更多
基金Supported by Funds from CNPq,No. 133834/2003-4Fundao Araucária, No. 023
文摘AIM: To investigate the effect of ascorbic acid (AA) dietary supplementation on myenteric neurons and epithelial cell proliferation of the jejunum of adult rats with chronic diabetes mellitus. METHODS: Thirty rats at 90 d of age were divided into three groups: Non-diabetic, diabetic and diabetic treated with AA (DA) (1 g/L). After 120 d of treatment with AA the animals were killed. The myenteric neurons were stained for myosin-V and analyzed quantitatively in an area of 11.2 mm2/animal. We further measured the cellular area of 500 neurons per group. We also determined the metaphasic index (MI) of the jejunum mucosa layer of about 2500 cells in the intestinal crypts, as well as the dimensions of 30 villi and 30 crypts/animal. The data area was analyzed using the Olympus BX40 microscope. RESULTS: There was an increase of 14% in the neuronal density (792.6 ± 46.52 vs 680.6 ± 30.27) and 4.4% in the cellular area (303.4 ± 5.19 vs 291.1 ± 6.0) respectively of the diabetic group treated with AA when compared to control diabetic animals. There were no signifi cant differences in MI parameters, villi height or crypt depths among the groups.CONCLUSION: Supplementation with AA in the diabetic animal promoted moderate neuroprotection. There was no observation of alteration of the cellular proliferation of the jejunum mucosa layer of rats with chronic diabetes mellitus with or without supplementation with AA.
文摘AIM;Oxidative stress participates in the cell carcinogenesis by inducing DNA mutations.Our aim was to assess whether ascorbic acid,an antioxidant,could have a role in preventing ROS(Reactive Oxygen Species)generation in experimental gastric carcinoma in a rat model. METHODS:Experimental gastric cancer was induced in twelve Wistar male rats(weighting 250-350 g)by profound duodeno-gastric reflux throught split gastrojenunostomy.The rats were allocated to the following groups:Group Ⅰ(n=6) was the control;Group Ⅱ(n=6)which was mantained with daily intake of tape water with Vitamin C(30 mg/Kg).After 6 or 12 months,samples of gastric tumor or non tumor mucosa were taken from the anastomosis of both groups. Oxidative stress was measured by superoxide quantification through lucigenin-amplified chemiluminescence base and by staining with Nitrobluetetrazolium.The histopathologic confirmation of adenocarcinoma was made by eosin- hemathoxilin method. RESULTS:The intestinal type of gastric adenocarcinoma was microscopically identified in all animals of group Ⅰ whereas only 3 rats of group Ⅱ showed an adenocarcinoma without macroscopic evidence of them.The cancers were located in the anastomosis in all cases.Basal luminescence from tumor gastric tissue generated 38.4±6.8 count per minute/mg/×10~6(mean±SD)and 14.9±4.0 count per minute/mg/×10~6,respectively,in group Ⅰ and Ⅱ animals(P <0.05).The Nitrobluetetrazolium method showed intense staining in tumor tissues but not in non neoplasic mucosa. CONCLUSION:Experimental gastric tumors seem to produce more reactive oxygen species than non neoplasic gastric tissue.The reduction of oxidative stress and gastric tumor incidence in rats were induced by the intake of ascorbic acid.Therefore,it may have a role in the prevention of gastric carcinoma. Oliveira CPMS Kassab P Lopasso FP Souza HP Janiszewski M Laurindo FRM Iriya K Laudanna AA.Protective effect of ascorbic acid in experimental gastric cancer:reduction of oxidative stress.World J Gastroenterol 2003;9(3):446-448 http://www.wjgnet.com/1007-9327/9/446.htm
基金Supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences(No.KZCX2-EWQ215)
文摘Different amounts of vitamin C were added to diets fed to juveniles （2.5＋0.15 g） of sea cucumber Apostichopus japonicus （Selenka） in an attempt to reduce the stress response of specimens exposed to nitrite stress. A commercial feed was used as the control diet and three experimental diets were made by supplementing 1 000, 1 500, or 2 000 mg vitamin C/kg diet to control diet separately in a 45-day experiment. Sea cucumbers were exposed to three different levels （0.5, 1.0, and 1.5 mg/L） of nitrite stress for 4, 8, and 12 h at four time intervals （0, 15, 30, and 45 d）. Growth of the animals was recorded during the experiment. Reactive oxygen species （ROS） （i.e. hydroxyl free radical （-OH）, malondialdehyde （MDA） and total antioxidant capacity （T-AOC）） and antioxidant enzyme activities （i.e., superoxide dismutase （SOD） and eatalase （CAT）） were measured. Response surface methodology （RSM） was used to analyze the effect of multiple factors on ROS indices and enzyme activities. Weight gain （WG） and special growth rate （SGR） of vitamin C supplementation groups were significantly higher than those of control group （P〈0.05）. The levels of-OH and MDA increased under exposure time extending and nitrite concentration increasing, whereas T-AOC level decreased. SOD and CAT activities increased at 4 h and 8 h and decreased at 12 h. During the days in which the animal consumed experimental diets, the levels of-OH and MDA decreased and that of T-AOC increased. This result suggests that diets containing vitamin C could reduce the nitrite stress response in the animals and increase their antioxidant capacity. The multifactor regression equation of growth performance, ROS indices, and duration of feeding results suggest that vitamin C supplementation of 1 400-2 000 mg/kg diet for 29-35 days could reduce effectively the effects of nitrite exposure.
文摘The synthesis and catalytic properties of copper nanoparticles（Cunps） were reported using L-ascorbic acid as reducing and capping agent in aqueous medium. The effect of different concentrations of L-ascorbic acid on the particle size of Cunps was investigated. The synthesized Cunps were characterized by UV-Visible spectrophotometer, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and Fourier transform infrared（FTIR） spectrophotometer. The result indicates that the size of copper nanoparticles decreases with the increase in concentration of L-ascorbic acid. L-Ascorbic acid plays an important role to protect the copper nanoparticles from oxidation and agglomeration which helps nanoparticles to get better stability for the application. The synthesized Cunps show excellent catalytic activity in the oxidation of serine（Ser） by peroxomonosulphate（PMS）. The catalytic activity of Cunps increases with the decrease in size of Cunps. The Cunps are expected to be suitable alternative and play an imperative role in the fields of catalysis and environmental remediation.
文摘Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphite （Na2S205） salt concentration （0%-2%） on vitamin C content, hardness （texture）, microbial count and color intensity of green pepper （Capsicum sinensis） during canning. Blanching, processing time and sodium metabisulphite （Na2S205） salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant （P 〈 0.05） interactions were noted between all the factors with high regression coefficients （78.7%-97.0%）. Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were： blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.
基金National Natural Science Foundation of China(Grant No.21271012)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20090001110068)
文摘The tight junction disorder plays an important role in the pathological process of many chronic diseases, and is becoming a major concern for the clinical application of metal drugs, i.e. anti-diabetic vanadium compounds. The development of novel tight junction protecting agents has thus been a major research focus. Since oxidative stress is the primary cause for vanadium toxicity, the present work tested the protective effects of zinc gluconate （Zn2＋） alone and when combined with vitamin C （VC） on the vanadium compound （VO（acac）z.）-mediated paracellular leakage of MDCK cells. The experimental results showed that VO（acac）2_ treatment significantly increased the paracellular permeability of MDCK monolayer. Zn2＋ alone showed no protective effects and VC ameliorated tight junction leakage of MDCK cells when given in the basal chamber. Interestingly, unilateral treatment with the combination of Zn2＋ and VC effectively prevented the increase of paracellular permeability. In addition, the combination of zinc and VC down-regulated the levels of reactive oxygen species in both the control and VO（acac）2-treated MDCK cells and caused the elevation of intracellular Ca2＋; both effects were beneficial for the maintenance of integrity of intercellular tight junction. Our results provided a simple but very effective method of preventing the metal toxicity for clinical aoNication of anti-diabetic vanadium compounds.
