WorldWideScience

Sample records for nitrite ameliorates dextran

  1. Hypertonic Saline Dextran Ameliorates Organ Damage in Beagle Hemorrhagic Shock.

    Directory of Open Access Journals (Sweden)

    Jing-xiang Zhao

    Full Text Available The goal of this study was to investigate the effect of hypertonic saline with 6% Dextran-70 (HSD resuscitation on organ damage and the resuscitation efficiency of the combination of HSD and lactated ringers (LR in a model of hemorrhage shock in dogs.Beagles were bled to hold their mean arterial pressure (MAP at 50 ± 5 mmHg for 1 h. After hemorrhage, beagles were divided into three groups (n = 7 to receive pre-hospital resuscitation for 1 h (R1: HSD (4 ml/kg, LR (40 ml/kg, and HSD+LR (a combination of 4 ml/kg HSD and 40 ml/kg LR. Next, LR was transfused into all groups as in-hospital resuscitation (R2. After two hours of observation (R3, autologous blood was transfused. Hemodynamic responses and systemic oxygenation were measured at predetermined phases. Three days after resuscitation, the animals were sacrificed and tissues including kidney, lung, liver and intestinal were obtained for pathological analysis.Although the initial resuscitation with HSD was shown to be faster than LR with regard to an ascending MAP, the HSD group showed a similar hemodynamic performance compared to the LR group throughout the experiment. Compared with the LR group, the systemic oxygenation performance in the HSD group was similar but showed a lower venous-to-arterial CO2 gradient (Pv-aCO2 at R3 (p < 0.05. Additionally, the histology score of the kidneys, lungs and liver were significantly lower in the HSD group than in the LR group (p < 0.05. The HSD+LR group showed a superior hemodynamic response but higher extravascular lung water (EVLW and lower arterial oxygen tension (PaO2 than the other groups (p < 0.05. The HSD+LR group showed a marginally improved systemic oxygenation performance and lower histology score than other groups.Resuscitation after hemorrhagic shock with a bolus of HSD showed a similar hemodynamic response compared with LR at ten times the volume of HSD, but HSD showed superior efficacy in organ protection. Our findings suggest that

  2. Dietary nitrite ameliorates renal injury in L-NAME-induced hypertensive rats.

    Science.gov (United States)

    Tsuchiya, Koichiro; Tomita, Shuhei; Ishizawa, Keisuke; Abe, Shinji; Ikeda, Yasumasa; Kihira, Yoshitaka; Tamaki, Toshiaki

    2010-02-15

    Nitric oxide (NO) has numerous important functions in the kidney, and long-term blockage of nitric oxide synthases in rats by L-NAME results in severe hypertension and progressive kidney damage. On the other hand, NO production seems to be low in patients with chronic kidney disease (CKD), and NO deficiency may play a role in CKD progression. In this review, we summarized the mechanisms of amelioration of renal injury induced by L-NAME treated rats by treatment of nitrite. First, we demonstrate whether orally-administrated nitrite-derived NO can shift to the circulation. When 3mg/kg body weight Na(15)NO(2) was orally administered to rats, an apparent EPR signal derived from Hb(15)NO (A(z)=23.4 gauss) appeared in the blood, indicating that orally ingested nitrite can be a source of NO in vivo. Next, in order to clarify the capacity of nitrite to prevent renal disease, we administered low-dose nitrite (LDN: 0.1mg of sodium nitrite in 1L of drinking water), medium-dose nitrite (MDN: 1mg sodium nitrite/L, which corresponds to the amount of nitrite ingested by vegetarians), or high-dose nitrite (HDN: 10mg sodium nitrite/L) to rats simultaneously with L-NAME (1 g l-NAME/L) for 8 weeks, then examined the blood NO level as a hemoglobin-NO adduct (iron-nitrosyl-hemoglobin) using electron paramagnetic resonance spectroscopy, urinary protein excretion, and renal histological changes at the end of the experiment. It was found that oral administration of MDN and HDN but not LDN increased the blood iron-nitrosyl-hemoglobin concentration to the normal level, ameliorated the L-NAME-induced proteinuria, and reduced renal histological damage. The findings demonstrate that chronic administration of a mid-level dietary dose of nitrite restores the circulating iron-nitrosyl-hemoglobin levels reduced by L-NAME and that maintenance of the circulating iron-nitrosyl-hemoglobin level in a controlled range protects against L-NAME-induced renal injury. Taking these findings together, we

  3. Exploring the ameliorative potential of Punica granatum in dextran sulfate sodium induced ulcerative colitis in mice.

    Science.gov (United States)

    Singh, Kavinder; Jaggi, Amteshwar Singh; Singh, Nirmal

    2009-11-01

    The present study was designed to investigate the ameliorative potential of Punica granatum in dextran sulfate sodium (DSS) induced ulcerative colitis. DSS (2%) was administered orally in drinking water for 7 days to induce ulcerative colitis. The extent and severity of ulceration was analysed macroscopically, histopathologically and using a disease activity index. Myeloperoxidase (MPO), a specific marker of inflammation; histamine, a marker of mast cell degranulation; superoxide anion generation and, lipid peroxides were analysed. Administration of DSS resulted in a significant development of ulceration in the colon along with a rise in histamine, MPO activity and oxidative stress. Treatment with Punica granatum extract and its ellagic acid rich fraction (100 mg/kg and 200 mg/kg p.o.) significantly attenuated DSS-induced colonic inflammation along with attenuation of histamine, MPO and oxidative stress. The antiulcerative effect of Punica granatum extract and its ellagic acid rich fraction were comparable to sulphasalazine (100 mg/kg, p.o.) and sodium cromoglycate (40 mg/kg i.p). It is concluded that Punica granatum has a potential for ameliorating DSS-induced colitis and its ellagic acid rich fraction may be responsible for this effect. Further, the antiulcerative effects may be attributed to mast cell stabilizing, antiinflammatory and antioxidant actions.

  4. Acute, Sub-lethal Cyanide Poisoning in Mice is Ameliorated by Nitrite Alone: Complications Arising from Concomitant Administration of Nitrite and Thiosulfate as an Antidotal Combination

    Science.gov (United States)

    Cambal, Leah K.; Swanson, Megan R.; Yuan, Quan; Weitz, Andrew C.; Li, Hui-Hua; Pitt, Bruce R.; Pearce, Linda L.; Peterson, Jim

    2011-01-01

    Sodium nitrite alone is shown to ameliorate sub-lethal cyanide toxicity in mice when given from ~1 hour before until 20 minutes after the toxic dose as demonstrated by the recovery of righting ability. An optimum dose (12 mg/kg) was determined to significantly relieve cyanide toxicity (5.0 mg/kg) when administered to mice intraperitoneally. Nitrite so administered was shown to rapidly produce NO in the bloodsteam as judged by the dose dependent appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. It is argued that antagonism of cyanide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity rather than the methemoglobin-forming action of nitrite. Concomitant addition of sodium thiosulfate to nitrite-treated blood resulted in the detection of sulfidomethemoblobin by EPR spectroscopy. Sulfide is a product of thiosulfate hydrolysis and, like cyanide, is known to be a potent inhibitor of cytochrome c oxidase; the effects of the two inhibitors being essentially additive under standard assay conditions, rather than dominated by either one. The findings afford a plausible explanation for an observed detrimental effect in mice associated with the use of the standard nitrite-thiosulfate combination therapy at sub-lethal levels of cyanide intoxication. PMID:21534623

  5. Dietary protocatechuic acid ameliorates dextran sulphate sodium-induced ulcerative colitis and hepatotoxicity in rats.

    Science.gov (United States)

    Farombi, Ebenezer O; Adedara, Isaac A; Awoyemi, Omolola V; Njoku, Chinonye R; Micah, Gabriel O; Esogwa, Cynthia U; Owumi, Solomon E; Olopade, James O

    2016-02-01

    The present study investigated the antioxidant and anti-inflammatory effects of dietary protocatechuic acid (PCA), a simple hydrophilic phenolic compound commonly found in many edible vegetables, on dextran sulphate sodium (DSS)-induced ulcerative colitis and its associated hepatotoxicity in rats. PCA was administered orally at 10 mg kg(-1) to dextran sulphate sodium exposed rats for five days. The result revealed that administration of PCA significantly (p rats. Furthermore, PCA prevented the increase in the plasma levels of pro-inflammatory cytokines, markers of liver toxicity and markedly suppressed the DSS-mediated elevation in colonic nitric oxide concentration and myeloperoxidase activity in the treated rats. Administration of PCA significantly protected against colonic and hepatic oxidative damage by increasing the antioxidant status and concomitantly decreased hydrogen peroxide and lipid peroxidation levels in the DSS-treated rats. Moreover, histological examinations confirmed PCA chemoprotection against colon and liver damage. Immunohistochemical analysis showed that PCA significantly inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression in the colon of DSS-treated rats. In conclusion, the effective chemoprotective role of PCA in colitis and the associated hepatotoxicity is related to its intrinsic anti-inflammatory and anti-oxidative properties.

  6. Glycyrrhetic Acid Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Vivo

    Directory of Open Access Journals (Sweden)

    Yong-Deok Jeon

    2016-04-01

    Full Text Available Glycyrrhizae Radix (GR is a Korean traditional herb medicine that is widely used in clinical health care. Glycyrrhetic acid (GA is an aglycone saponin extracted from GR that has anti-inflammatory, anti-cancer, and anti-viral effects. However, the anti-inflammatory effects of GA in colitis have not been reported. This study investigated the role of GA on ulcerative colitis in a dextran sulfate sodium (DSS-induced mouse colitis model. DSS-treated mice displayed weight loss and shortened colon length compared with control mice. Mice administered GA showed less weight loss and longer colon length than the DSS-treated group. Interleukin (IL-6, IL-1β, and tumor necrosis factor-alpha were decreased by GA treatment. GA treatment also reduced DSS-induced microscopic damage to colon tissue. GA regulates the phosphorylation of transcription factors including nuclear factor-kappa B (NF-κB and IκB alpha, and regulates the expression of cycloxygenase-2 and prostaglandin E2. GA thus showed beneficial effects in a mouse model of colitis, implicating GA might be a useful herb-derived medicine in the treatment of ulcerative colitis.

  7. Thymoquinone ameliorates testicular tissue inflammation induced by chronic administration of oral sodium nitrite.

    Science.gov (United States)

    Alyoussef, A; Al-Gayyar, M M H

    2016-06-01

    Although sodium nitrite has been widely used as food preservative, building bases of scientific evidence about nitrite continues to oppose the general safety in human health. Moreover, thymoquinone (TQ) has therapeutic potential as antioxidant, anti-inflammatory, antibacterial and anticancer. Therefore, we investigated the effects of both sodium nitrite and TQ on testicular tissues of rats. Forty adult male Sprague Dawley rats were used. They received either 80 mg kg(-1) sodium nitrite or 50 mg kg(-1) TQ daily for twelve weeks. Serum testosterone was measured. Testis were weighed and the testicular tissue homogenates were used for measurements of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-4, IL-6, IL10, caspase-3, caspase-8 and caspase-9. Sodium nitrite resulted in significant reduction in serum testosterone concentration and elevation in testis weight and Gonado-Somatic Index. We found significant reduction in testicular tissues levels of IL-4 and IL-10 associated with elevated levels of TNF-α, IL-1β, IL-6, caspase-3, caspase-8 and caspase-9. In conclusion, chronic oral sodium nitrite induced changes in the weight of rat testis accompanied by elevation in the testicular tissue level of oxidative stress markers and inflammatory cytokines. TQ attenuated sodium nitrite-induced testicular tissue damage through blocking oxidative stress, restoration of normal inflammatory cytokines balance and blocking of apoptosis.

  8. Kefir treatment ameliorates dextran sulfate sodium-induced colitis in rats

    Science.gov (United States)

    Senol, Altug; Isler, Mehmet; Sutcu, Recep; Akin, Mete; Cakir, Ebru; Ceyhan, Betul M; Kockar, M Cem

    2015-01-01

    AIM: To investigate the preventive effect of kefir on colitis induced with dextran sulfate sodium (DSS) in rats. METHODS: Twenty-four male Wistar-albino rats were randomized into four groups: normal control, kefir-control, colitis, and kefir-colitis groups. Rats in the normal and kefir-control groups were administered tap water as drinking water for 14 d. Rats in the colitis and kefir-colitis groups were administered a 3% DSS solution as drinking water for 8-14 d to induce colitis. Rats in the kefir-control and kefir-colitis groups were administered 5 mL kefir once a day for 14 d while rats in the normal control and colitis group were administered an identical volume of the placebo (skim milk) using an orogastric feeding tube. Clinical colitis was evaluated with reference to the disease activity index (DAI), based on daily weight loss, stool consistency, and presence of bleeding in feces. Rats were sacrificed on the 15th day, blood specimens were collected, and colon tissues were rapidly removed. Levels of myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, interleukin (IL)-10, malondialdehyde, and inducible nitric oxide synthase (iNOS) were measured in colon tissue. RESULTS: The DAI was lower in the kefir-colitis group than in the colitis group (on the 3rd and 5th days of colitis induction; P colitis group between days 2 and 6 of colitis induction when compared to the normal control and kefir-control groups. The DAI was statistically higher only on the 6th day in the kefir-colitis group when compared to that in the normal control groups. Increased colon weight and decreased colon length were observed in colitis-induced rats. Mean colon length in the colitis group was significantly shorter than that of the kefir-control group. Kefir treatment significantly decreased histologic colitis scores (P colitis group was significantly higher than in the kefir-control group (P colitis-induced TNF-α increase (P colitis group were significantly higher than those in the

  9. Tanshinone IIA ameliorates dextran sulfate sodium-induced inflammatory bowel disease via the pregnane X receptor

    Directory of Open Access Journals (Sweden)

    Zhang X

    2015-12-01

    , Crohn’s disease, tanshinone IIA, pregnane X receptor, inflammatory bowel disease, dextran sodium sulfate

  10. Kefir treatment ameliorates dextran sulfate sodium-induced colitis in rats.

    Science.gov (United States)

    Senol, Altug; Isler, Mehmet; Sutcu, Recep; Akin, Mete; Cakir, Ebru; Ceyhan, Betul M; Kockar, M Cem

    2015-12-14

    To investigate the preventive effect of kefir on colitis induced with dextran sulfate sodium (DSS) in rats. Twenty-four male Wistar-albino rats were randomized into four groups: normal control, kefir-control, colitis, and kefir-colitis groups. Rats in the normal and kefir-control groups were administered tap water as drinking water for 14 d. Rats in the colitis and kefir-colitis groups were administered a 3% DSS solution as drinking water for 8-14 d to induce colitis. Rats in the kefir-control and kefir-colitis groups were administered 5 mL kefir once a day for 14 d while rats in the normal control and colitis group were administered an identical volume of the placebo (skim milk) using an orogastric feeding tube. Clinical colitis was evaluated with reference to the disease activity index (DAI), based on daily weight loss, stool consistency, and presence of bleeding in feces. Rats were sacrificed on the 15(th) day, blood specimens were collected, and colon tissues were rapidly removed. Levels of myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, interleukin (IL)-10, malondialdehyde, and inducible nitric oxide synthase (iNOS) were measured in colon tissue. The DAI was lower in the kefir-colitis group than in the colitis group (on the 3(rd) and 5(th) days of colitis induction; P kefir-control groups. The DAI was statistically higher only on the 6(th) day in the kefir-colitis group when compared to that in the normal control groups. Increased colon weight and decreased colon length were observed in colitis-induced rats. Mean colon length in the colitis group was significantly shorter than that of the kefir-control group. Kefir treatment significantly decreased histologic colitis scores (P kefir-control group (P Kefir treatment significantly reduced the DSS colitis-induced TNF-α increase (P kefir-colitis groups (P Kefir reduces the clinical DAI and histologic colitis scores in a DSS-induced colitis model, possibly via reduction of MPO, TNF-α, and iNOS levels.

  11. Neutralization of complement component C5 ameliorates the development of dextran sulfate sodium (DSS)-colitis in mice

    Science.gov (United States)

    Aomatsu, Tomoki; Imaeda, Hirotsugu; Takahashi, Kenichiro; Fujimoto, Takehide; Kasumi, Eiji; Ban, Hiromitsu; Bamba, Shigeki; Yoden, Atsushi; Tamai, Hiroshi; Fujiyama, Yoshihide; Andoh, Akira

    2013-01-01

    The complement system is a potent effector of innate immunity. To elucidate the pathophysiological role of the complement system in inflammatory bowel disease, we evaluated the effects of anti-C5 antibodies on the development of dextran sulfate sodium-induced colitis in mice. Dextran sulfate sodium-colitis was induced in BALB/c mice with intraperitoneal administrations of anti-C5 antibodies (1 µg/body) every 48 h. Tissue samples were evaluated by standard histological procedures. The mucosal mRNA expression of the inflammatory cytokines was analyzed by real-time PCR. Body weight loss in the mice was completely blocked by the administration of anti-C5 antibody. The disease activity index was significantly lower in the anti-C5 antibody-treated mice than the dextran sulfate sodium mice. The colonic weight/length ratio, histological colitis score and mucosal myeloperoxidase activity were significantly lower in the anti-C5 antibody-treated mice than the dextran sodium sulfate mice. The administration of the anti-C5 antibody significantly reduced the mucosal expression of mRNAs for tumor necrosis factor-α, interleukin-1β and interleukin-6. In conclusion, the complement system plays a role in the development of dextran sodium sulfate-induced experimental colitis. PMID:23341701

  12. Orally administered lactoperoxidase ameliorates dextran sulfate sodium-induced colitis in mice by up-regulating colonic interleukin-10 and maintaining peripheral regulatory T cells.

    Science.gov (United States)

    Shin, Kouichirou; Horigome, Ayako; Yamauchi, Koji; Yaeshima, Tomoko; Iwatsuki, Keiji

    2009-11-01

    We previously demonstrated orally administered bovine lactoperoxidase (LPO) ameliorated dextran sulfate sodium-induced colitis in mice. Here, we examine the mechanism of action of LPO. Three days after colitis induction, expression of interferon-gamma mRNA in colonic tissue was significantly decreased in mice administered LPO; while mRNA expression of interleukin (IL)-10 and regulatory T cell (Treg) marker, Foxp3, were significantly increased. The proportion of CD4+CD25+ Tregs in peripheral CD4+ T cells was also significantly elevated when LPO was administered. Nine days after colitis induction, the severity of colitis symptoms, including body weight loss and colon shortening, was reduced and expression of IL-10 mRNA was increased in mice administered LPO. The proportion of CD4+CD25+ Tregs in peripheral leukocytes was also significantly elevated when LPO was administered. These results suggest LPO ameliorates colitis by up-regulating colonic anti-inflammatory cytokines and maintaining peripheral regulatory T cells.

  13. Luteolin ameliorates dextran sulfate sodium-induced colitis in mice possibly through activation of the Nrf2 signaling pathway.

    Science.gov (United States)

    Li, Yue; Shen, Lei; Luo, Hesheng

    2016-11-01

    Luteolin has a reputation for being a safe and effective natural antioxidant that has strong radical scavenging and cell protective properties. The role of oxidative stress in inflammatory bowel disease (IBD) has been well established and is increasingly highlighted. Thus, we studied the protective effect of luteolin administration in a mouse model of experimental colitis. Experimental acute colitis was induced by administering 3% dextran sulfate sodium (DSS) in the drinking water of mice for 7days. The disease activity index (DAI); colon length; histological assessment; mRNA levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), heme oxygenase-1 (HO-1), and NADP(H): quinone oxidoreductase 1 (NQO-1); protein expression of Nrf2 and inducible nitric oxide synthase (iNOS); colon malondialdehyde (MDA) levels; and the activity levels of colonic superoxide dismutase (SOD) and catalase (CAT) were examined. Luteolin (20 and 50mg/kg) significantly attenuated the DAI, colon shortening and histological damage. In addition, luteolin administration effectively decreased the expression of inflammatory mediators, such as iNOS, TNF-α and IL-6. Luteolin also decreased the colonic content of MDA. The activities of colonic SOD and CAT and the levels of Nrf2 and its downstream targets, HO-1 and NQO1, were elevated by luteolin treatment. These observations indicate that luteolin may suppress experimental colitis through the Nrf2 signaling pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Ultraviolet A eye irradiation ameliorates colon carcinoma induced by azoxymethane and dextran sodium sulfate through β-endorphin and methionine-enkephalin.

    Science.gov (United States)

    Hiramoto, Keiichi; Yokoyama, Satoshi; Yamate, Yurika

    2017-03-01

    We previously reported that ultraviolet (UV) A eye irradiation reduces the ulcerative colitis induced by dextran sodium sulfate (DSS). This study examined the effects of UVA on colon carcinoma induced by azoxymethane (AOM) and DSS. We irradiated the eyes of ICR mice with UVA at a dose of 110 kJ/m(2) using an FL20SBLB-A lamp for the experimental period. In mice treated with these drugs, the symptom of colon carcinoma was reduced by UVA eye irradiation. The levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in the blood were increased in AOM + DSS-treated mice; however, those levels were reduced by UVA eye irradiation. The expression of β-endorphin, methionine-enkephalin (OGF), μ-opioid receptor, and opioid growth factor receptor (OGFR) of the colon was increased in the AOM + DSS-treated mice, and these levels were increased further following UVA eye irradiation. When β-endorphin inhibitor was administered, the ameliorative effect of UVA eye irradiation was reduced, and the effect of eye irradiation disappeared entirely following the administration of naltrexone (inhibitor of both opioid receptor and OGFR). These results suggested that UVA eye irradiation exerts major effects on AOM + DSS-induced colon carcinoma. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Sarcodon aspratus Extract Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mouse Colon and Mesenteric Lymph Nodes.

    Science.gov (United States)

    Chung, Min-Yu; Hwang, Jin-Taek; Kim, Jin Hee; Shon, Dong-Hwa; Kim, Hyun-Ku

    2016-05-01

    Mushrooms have been previously investigated for their immune-modulating and anti-inflammatory properties. We examined whether the anti-inflammatory properties of Sarcodon aspratus ethanol extract (SAE) could elicit protective effects against dextran sulfate sodium (DSS)-induced colitis in vivo. Male C57/BL6 mice were randomly assigned to 1 of 4 treatment groups: control (CON; n = 8), DSS-treated (DSS; n = 9), DSS+SAE at 50 mg/kg BW (SAE50; n = 8), and DSS+SAE at 200 mg/kg BW groups (SAE200; n = 9). DSS treatment induced significant weight loss, which was significantly recovered by SAE200. Although SAE did not affect DSS-mediated reductions in colon length, it improved diarrhea and rectal bleeding induced by DSS. SAE at 200 mg/kg BW significantly attenuated IL-6 and enhanced IL-10 expression in mesenteric lymph nodes (MLN), and significantly reduced IL-6 levels in splenocytes. SAE200 also significantly attenuated DSS-induced increase in IL-6 and IL-1β, and reductions in IL-10 in colon tissue. High levels of SAE were also observed to significantly decrease inflammatory COX-2 expression that was upregulated by DSS in mice colon. These findings may have relevance for novel therapeutic strategies to mitigate inflammatory bowel disease-relevant inflammatory responses, via the direct and indirect anti-inflammatory activity of SAE. We also found that SAE harbors significant quantities of total fiber and β-glucan, suggesting a possible role for these components in protection against DSS-mediated colitis.

  16. Calcitriol analog ZK191784 ameliorates acute and chronic dextran sodium sulfate-induced colitis by modulation of intestinal dendritic cell numbers and phenotype

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the effects of ZK1916784, a low calcemic analog of calcitriol on intestinal inflammation.METHODS: Acute and chronic colitis was induced by dextran sodium sulfate (DSS) according to standard procedures. Mice were treated intraperitoneally with ZK1916784 or placebo and colonic inflammation was evaluated. Cytokine production by mesenterial lymph node (MLN) cells was measured by ELISA.Immunohistochemistry was performed to detect intestinal dendritic cells (DCs) within the colonic tissue,and the effect of the calcitriol analog on DCs was investigated.RESULTS: Treatment with ZK191784 resulted in significant amelioration of disease with a reduced histological score in acute and chronic intestinal inflammation. In animals with acute DSS colitis, down-regulation of colonic inflammation was associated with a dramatic reduction in the secretion of the proinflammatory cytokine interferon (IFN)-γ and a significant increase in intereleukin (IL)-10 by MLN cells.Similarly, in chronic colitis, IL-10 expression in colonic tissue increased 1.4-fold when mice were treated with ZK191784, whereas expression of the Th1-specific transcription factor T-beta decreased by 81.6%. Lower numbers of infiltrating activated CD11c+ DCs were found in the colon in ZK191784-treated mice with acute DSS colitis, and secretion of proinflammatory cytokines by primary mucosal DCs was inhibited in the presence of the calcitriol analog.CONCLUSION: The calcitriol analog ZK191784 demonstrated significant anti-inflammatory properties in experimental colitis that were at least partially mediated by the immunosuppressive effects of the derivate on mucosal DCs.

  17. Gingko biloba extract (Ginaton) ameliorates dextran sulfate sodium (DSS)-induced acute experimental colitis in mice via reducing IL-6/STAT3 and IL-23/IL-17.

    Science.gov (United States)

    Sun, Yan; Lin, Lian-Jie; Lin, Yan; Sang, Li-Xuan; Jiang, Min; Zheng, Chang-Qing

    2015-01-01

    This study explored the underlying mechanism of Gingko biloba extract (Ginaton) on dextran sulfate sodium (DSS)-induced acute experimental colitis in mice. 40 male C57BL/6 mice were randomly divided into four groups: normal control group, Ginaton group, Ginaton treatment group, and DSS group. After 7 days administration, mice were sacrificed and colons were collected for H-E staining, immunohistochemistry, real-time PCR and Western blot. By observing clinical disease activity and histological damage, we assessed the effect of Ginaton on DSS-induced acute experimental colitis in mice and observed the effect of Ginaton on normal mice. We also explored the specific mechanism of Ginaton on DSS-induced acute experimental colitis in mice through examining the expression of inflammatory related mediators (gp130, STAT3, p-STAT3, ROR-γt) and cytokines (IL-6, IL-17, IL-23). Ginaton-treated DSS mice showed significant improvement over untreated DSS mice. Specifically, Ginaton improved clinical disease activity (DAI score, weight closs, colon shortening, and bloody stool) and histological damage, and reduced the expression of inflammatory-related mediators (p-STAT3, gp130, ROR-γt) and cytokines (IL-6, IL-17, IL-23). In addition, clinical disease activity, histological damage, the expression of inflammatory related mediators (STAT3, p-STAT3, gp130, ROR-t) and cytokines (IL-6, IL-17, IL-23) in mice of Ginaton group were similar to normal control group. In conclusion, Ginaton ameliorates DSS-induced acute experimental colitis in mice by reducing IL-17 production, which is at least partly involved in inhibiting IL-6/STAT3 signaling pathway and IL-23/IL-17 axis. Moreover, Ginaton itself does not cause inflammatory change in normal mice. These results support that Ginaton can be as a potential clinical treatment for ulcerative colitis (UC).

  18. Nitrite Therapy Ameliorates Myocardial Dysfunction via H2S and Nuclear Factor-Erythroid 2-Related Factor 2 (Nrf2)-Dependent Signaling in Chronic Heart Failure.

    Science.gov (United States)

    Donnarumma, Erminia; Bhushan, Shashi; Bradley, Jessica M; Otsuka, Hiroyuki; Donnelly, Erinn L; Lefer, David J; Islam, Kazi N

    2016-07-29

    Bioavailability of nitric oxide (NO) and hydrogen sulfide (H2S) is reduced in heart failure (HF). Recent studies suggest cross-talk between NO and H2S signaling. We previously reported that sodium nitrite (NaNO2) ameliorates myocardial ischemia-reperfusion injury and HF. Nuclear factor-erythroid-2-related factor 2 (Nrf2) regulates the antioxidant proteins expression and is upregulated by H2S. We examined the NaNO2 effects on endogenous H2S bioavailability and Nrf2 activation in mice subjected to ischemia-induced chronic heart failure (CHF). Mice underwent 60 minutes of left coronary artery occlusion and 4 weeks of reperfusion. NaNO2 (165 μg/kgic) or vehicle was administered at reperfusion and then in drinking water (100 mg/L) for 4 weeks. Left ventricular (LV), ejection fraction (EF), LV end diastolic (LVEDD) and systolic dimensions (LVESD) were determined at baseline and at 4 weeks of reperfusion. Myocardial tissue was analyzed for oxidative stress and respective gene/protein-related assays. We found that NaNO2 therapy preserved LVEF, LVEDD and LVSD at 4 weeks during ischemia-induced HF. Myocardial malondialdehyde and protein carbonyl content were significantly reduced in NaNO2-treated mice as compared to vehicle, suggesting a reduction in oxidative stress. NaNO2 therapy markedly increased expression of Cu,Zn-superoxide dismutase, catalase, and glutathione peroxidase during 4 weeks of reperfusion. Furthermore, NaNO2 upregulated the activity of Nrf2, as well as H2S-producing enzymes, and ultimately increased H2S bioavailability in ischemia-induced CHF in mice as compared with vehicle. Our results demonstrate that NaNO2 therapy significantly improves LV function via increasing H2S bioavailability, Nrf2 activation, and antioxidant defenses. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  19. Hydroalcoholic Extract from Inflorescences of Achyrocline satureioides (Compositae) Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice by Attenuation in the Production of Inflammatory Cytokines and Oxidative Mediators

    Science.gov (United States)

    da Silva, Luisa Mota; Farias, Jaime Antonio Machado; Boeing, Thaise; Somensi, Lincon Bordignon; Beber, Ana Paula; Cury, Benhur Judah

    2016-01-01

    Achyrocline satureioides is a South American herb used to treat inflammatory and gastrointestinal diseases. This study evaluated intestinal anti-inflammatory effects of the hydroalcoholic extract of inflorescences of satureioides (HEAS) in dextran sulfate sodium (DSS) induced colitis in mice. Mice were orally treated with vehicle, 5-aminosalicylic acid (100 mg/kg), or HEAS (1–100 mg/kg). Clinical signs of colitis and colonic histopathological parameters were evaluated, along with the determination of levels of reduced glutathione and lipid hydroperoxide (LOOH), the superoxide dismutase (SOD), and myeloperoxidase (MPO) activity in colon. The colonic content of cytokines (TNF, IL-4, IL-6, and IL-10) was measured. Additionally, the effects of the extract on nitric oxide (NO) release by lipopolysaccharide (LPS) stimulated macrophages and diphenylpicrylhydrazyl levels were determined. Mucin levels and SOD activity, as well as the LOOH, MPO, TNF, and IL-6 accumulation in colon tissues, were normalized by the HEAS administration. In addition, the extract elicited an increase in IL-4 and IL-10 levels in colon. NO release by macrophages was inhibited by HEAS and its scavenger activity was confirmed. Together these results suggest that preparations obtained from inflorescences from A. satureioides could be used in treatment for IBD. Besides, this work corroborates the popular use of A. satureioides in inflammatory disorders. PMID:27847525

  20. Hydroalcoholic Extract from Inflorescences of Achyrocline satureioides (Compositae Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice by Attenuation in the Production of Inflammatory Cytokines and Oxidative Mediators

    Directory of Open Access Journals (Sweden)

    Luisa Mota da Silva

    2016-01-01

    Full Text Available Achyrocline satureioides is a South American herb used to treat inflammatory and gastrointestinal diseases. This study evaluated intestinal anti-inflammatory effects of the hydroalcoholic extract of inflorescences of satureioides (HEAS in dextran sulfate sodium (DSS induced colitis in mice. Mice were orally treated with vehicle, 5-aminosalicylic acid (100 mg/kg, or HEAS (1–100 mg/kg. Clinical signs of colitis and colonic histopathological parameters were evaluated, along with the determination of levels of reduced glutathione and lipid hydroperoxide (LOOH, the superoxide dismutase (SOD, and myeloperoxidase (MPO activity in colon. The colonic content of cytokines (TNF, IL-4, IL-6, and IL-10 was measured. Additionally, the effects of the extract on nitric oxide (NO release by lipopolysaccharide (LPS stimulated macrophages and diphenylpicrylhydrazyl levels were determined. Mucin levels and SOD activity, as well as the LOOH, MPO, TNF, and IL-6 accumulation in colon tissues, were normalized by the HEAS administration. In addition, the extract elicited an increase in IL-4 and IL-10 levels in colon. NO release by macrophages was inhibited by HEAS and its scavenger activity was confirmed. Together these results suggest that preparations obtained from inflorescences from A. satureioides could be used in treatment for IBD. Besides, this work corroborates the popular use of A. satureioides in inflammatory disorders.

  1. Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester, a polymeric colon-specific prodrug releasing 5-aminosalicylic acid and benzocaine, ameliorates TNBS-induced rat colitis.

    Science.gov (United States)

    Nam, Joon; Kim, Wooseong; Lee, Sunyoung; Jeong, Seongkeun; Yoo, Jin-Wook; Kim, Min-Soo; Jung, Yunjin

    2016-01-01

    Local anesthetics have beneficial effects on colitis. Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester (Dex-5-ESA), designed as a polymeric colon-specific prodrug liberating 5-ASA and benzocaine in the large intestine, was prepared and its therapeutic activity against colitis was evaluated using a TNBS-induced rat colitis model. Dex-5-ESA liberated 5-ASA and benzocaine in the cecal contents while (bio)chemically stable in the small intestinal contents and mucosa. Oral administration of Dex-5-ESA (equivalent to 10 mg 5-ASA/kg, twice a day) alleviated colonic injury and reduced MPO activity in the inflamed colon. In parallel, pro-inflammatory mediators, COX-2, iNOS and CINC-3, elevated by TNBS-induced colitis, were substantially diminished in the inflamed colon. Dex-5-ESA was much more effective for the treatment of colitis than 5-(4-ethoxycarbonylphenylazo)salicylic acid (5-ESA) that may not deliver benzocaine to the large intestine. Our data suggest that Dex-5-ESA is a polymeric colon-specific prodrug, liberating 5-ASA and benzocaine in the target site (large intestine), probably exerting anti-colitic effects by combined action of 5-ASA and benzocaine.

  2. Genetic deletion of Klf4 in the mouse intestinal epithelium ameliorates dextran sodium sulfate-induced colitis by modulating the NF-κB pathway inflammatory response.

    Science.gov (United States)

    Ghaleb, Amr M; Laroui, Hamed; Merlin, Didier; Yang, Vincent W

    2014-05-01

    Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor expressed in the differentiated epithelial cells lining of the intestine. Under physiological conditions, KLF4 inhibits cell proliferation. Conversely, KLF4 mediates proinflammatory signaling in macrophages and its overexpression in the esophageal epithelium activates cytokines, leading to inflammation-mediated esophageal squamous cell cancer formation in mice. Here, we tested whether KLF4 has a proinflammatory activity in experimental colitis in mice. Villin-Cre;Klf4 mice with intestine-specific Klf4 deletion (Klf4) and control mice with floxed Klf4 gene (Klf4) were treated or not with 3% dextran sodium sulfate (DSS) for 7 days to induce colitis. Additionally, WT mice were administered or not, nanoparticles loaded with scrambled or Klf4-siRNA, and concomitantly given DSS. Compared with DSS-treated Klf4 mice, DSS-treated Klf4 mice were significantly less sensitive to DSS-induced colitis. DSS treatment of Klf4 mice induced Klf4 expression in the crypt zone of the colonic epithelium. DSS-treated Klf4 mice had increased proliferation relative to DSS-treated control mice. DSS treatment induced NF-κB signaling pathway in Klf4 mice colon but not Klf4 mice. Additionally, WT mice given DSS and nanoparticle/Klf4-siRNA were less sensitive to colitis and had reduced Klf4 expression and while maintaining the proliferative response in the colonic epithelium. Our results indicate that Klf4 is an important mediator of DSS-induced colonic inflammation by modulating NF-κB signaling pathway and could be involved in the pathogenesis and/or propagation of inflammatory bowel disease. Thus, Klf4 may represent a novel therapeutic target in inflammatory bowel disease.

  3. Fermented Pueraria Lobata extract ameliorates dextran sulfate sodium-induced colitis by reducing pro-inflammatory cytokines and recovering intestinal barrier function

    Science.gov (United States)

    Choi, Seungho; Woo, Jong-Kyu; Jang, Yeong-Su; Kang, Ju-Hee; Jang, Jung-Eun; Yi, Tae-Hoo; Park, Sang-Yong; Kim, Sun-Yeou; Yoon, Yeo-Sung

    2016-01-01

    Inflammatory bowel disease is a chronic inflammatory disorder occurring in the gastrointestinal track. However, the efficacy of current therapeutic strategies has been limited and accompanied by side effects. In order to eliminate the limitations, herbal medicines have recently been developed for treatment of IBD. Peuraria Lobata (Peuraria L.) is one of the traditional herbal medicines that have anti-inflammatory effects. Bioavailability of Peuraria L., which is rich in isoflavones, is lower than that of their fermented forms. In this study, we generated fermented Peuraria L. extracts (fPue) and investigated the role of fPue in inflammation and intestinal barrier function in vitro and in vivo. As the mice or intestinal epithelial cells were treated with DSS/fPue, mRNA expression of pro-inflammatory cytokines was reduced and the architecture and expression of tight junction proteins were recovered, compared to the DSS-treated group. In summary, fPue treatment resulted in amelioration of DSS-induced inflammation in the colon, and the disrupted intestinal barrier was recovered as the expression and architecture of tight junction proteins were retrieved. These results suggest that use of fPue could be a new therapeutic strategy for treatment of IBD. PMID:27729931

  4. Iron Dextran Injection

    Science.gov (United States)

    ... allergic to iron dextran injection; any other iron injections such as ferric carboxymaltose (Injectafer), ferumoxytol (Feraheme), iron sucrose (Venofer), or sodium ferric gluconate (Ferrlecit);any other ...

  5. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  6. Dextran-modified iron oxide nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ji(r)í Hradil; Alexander Pisarev; Michal Babi(c); Daniel Horák

    2007-01-01

    Dextran-modified iron oxide nanoparticles were prepared by precipitation of Fe(Ⅱ) and Fe(Ⅲ) salts with ammonium hydroxide by two methods.Iron oxide was precipitated either in the presence of dextran solution, or the dextran solution was added after precipitation. In the second method,the iron oxide particle size and size distribution could be controlled depending on the concentration of dextran in the solution. The nanoparticles were characterized by size-exclusion chromatography, transmission electron microscopy and dynamic light scattering. Optimal conditions for preparation of stable iron oxide colloid particles were determined. The dextran/iron oxide ratio 0-0.16 used in precipitation of iron salts can be recommended for synthesis of nanoparticles suitable for biomedical applications, as the colloid does not contain excess dextran and does not coagulate.

  7. ADVANCED TECHNOLOGY WASTEWATER TREATMENT OF NITRITE IONS

    Directory of Open Access Journals (Sweden)

    E.G. Morozov

    2012-06-01

    Full Text Available The main reason for high concentration of nitrite ions in water is the existence of sources of industrial and agricultural pollution. Contamination of drinking water, juices, wine and other liquids of nitrite ions as a result of improper use of nitrogen fertilizers has an adverse effect on living organism, because under the influence of enzymes nitrite ions in living organisms form high carcinogenic nitrosamines, and the interaction of nitrite ions from blood hemoglobin causes such toxicity that leads to disease cyanosis [1]. Therefore removal of nitrite ions from water has received increased attention. The paper discusses an innovative wastewater treatment technology from the nitrite ion with hypochlorite produced during electrolysis.

  8. ADVANCED TECHNOLOGY WASTEWATER TREATMENT OF NITRITE IONS

    OpenAIRE

    E. G. Morozov; V.M. Nikol`skii; T.V. Saprunova; A.A. Yakovlev

    2012-01-01

    The main reason for high concentration of nitrite ions in water is the existence of sources of industrial and agricultural pollution. Contamination of drinking water, juices, wine and other liquids of nitrite ions as a result of improper use of nitrogen fertilizers has an adverse effect on living organism, because under the influence of enzymes nitrite ions in living organisms form high carcinogenic nitrosamines, and the interaction of nitrite ions from blood hemoglobin causes such toxicity t...

  9. 21 CFR 172.175 - Sodium nitrite.

    Science.gov (United States)

    2010-04-01

    ... Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite. 172.175 Section 172.175 Food and... preservative and color fixative, with sodium nitrate, in meat-curing preparations for the home curing of...

  10. Factors that Interfere in Dextran Production By Sugarcane Contaminating Microorganisms

    Directory of Open Access Journals (Sweden)

    Maria Celia Oliveira Hauly

    2002-01-01

    Full Text Available Dextrans are polysaccharides produced by microorganisms, specially bacterias from the Leuconostoc genus. Dextrans have a high molecular weigh and most of the glycosidic bonds are a(1®6. For the sugar manufacture, dextran is a problem which changes the quality of sugar and the industry efficiency. Dextrans are synthesized when the sugarcane is spoiled before the harvest period, through the sugarcane fissures, which permit the penetration of microorganisms that deteriorate the sugarcane. This work aims at improving the sugar quality and the industry efficiency by isolating dextran producing microorganisms, comparing the time of burning with the infection index and the dextran concentration in the sugarcane juice. Dextran producing microorganisms were isolated from sugarcane juice during the 97/98; 99/00 and 2001 harvests. The isolated strains were maintained in MRS agar at the temperature of 4°C. The fermentation was carried out in MRS broth for 72 hours at 28°C with 180 rpm. Dextran was analyzed by spectrophotometry at 485 nm. Only three isolated strains showed good dextran production. The average of dextran production in MRS broth was 390 mg%. It was observed that a burning period above 72 hours increases the sugarcane contamination and causes high dextran production, and consequently the reduction of the industry efficiency of the sugar factory.

  11. Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

    Science.gov (United States)

    Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

    2017-08-01

    Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

  12. Dextran: A promising macromolecular drug carrier

    Directory of Open Access Journals (Sweden)

    Dhaneshwar Suneela

    2006-01-01

    Full Text Available Over the past three decades intensive efforts have been made to design novel systems able to deliver the drug more effectively to the target site. The ongoing intense search for novel and innovative drug delivery systems is predominantly a consequence of the well-established fact that the conventional dosage forms are not sufficiently effective in conveying the drug compound to its site of action and once in the target area, in releasing the active agent over a desired period of time. The potential use of macromolecular prodrugs as a means of achieving targeted drug delivery has attracted considerable interest in recent years. Macromolecules such as antibodies, lipoproteins, lectins, proteins, polypeptides, polysaccharides, natural as well as synthetic polymers offer potential applicabilities as high molecular weight carriers for various therapeutically active compounds. Dextrans serve as one of the most promising macromolecular carrier candidates for a wide variety of therapeutic agents due to their excellent physico-chemical properties and physiological acceptance. The present contribution attempts to review various features of the dextran carrier like its source, structural and physico-chemical characteristics, pharmacokinetic fate and its applications as macromolecular carrier with special emphasis on dextran prodrugs.

  13. Dietary Nitrite: from menace to marvel

    Directory of Open Access Journals (Sweden)

    Nathan S. Bryan

    2016-11-01

    Full Text Available The health benefits of nitrite are now indisputable when administered in a clinical setting for specific diseases. Currently, most published reports identify the production of nitric oxide (NO as the mechanism of action for nitrite. Basic science, in addition to clinical studies, demonstrate that nitrite and/or nitrate cannot restore NO homeostasis as an endothelium independent source of NO that may be a redundant system for endogenous NO production. Nitrate must first be reduced to nitrite by oral commensal bacteria; nitrite can then be further reduced to NO along the physiological oxygen gradient. But despite decades of rigorous research on sodium nitrate’s safety and efficacy as a curing agent, sodium nitrite is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite which are being developed as novel therapies for conditions associated with nitric oxide insufficiency. Thus, this review will highlight the fundamental biochemistry of nitrite in human physiology and provide evidence that nitrite be considered an essential nutrient. Foods or diets enriched with nitrite can have profound positive health benefits.

  14. Antagonism of Acute Sulfide Poisoning in Mice by Nitrite Anion without Methemoglobinemia.

    Science.gov (United States)

    Cronican, Andrea A; Frawley, Kristin L; Ahmed, Humza; Pearce, Linda L; Peterson, Jim

    2015-07-20

    There are currently no FDA-approved antidotes for H2S/sulfide intoxication. Sodium nitrite, if given prophylactically to Swiss Webster mice, was shown to be highly protective against the acute toxic effects of sodium hydrosulfide (∼LD40 dose) with both agents administered by intraperitoneal injections. However, sodium nitrite administered after the toxicant dose did not detectably ameliorate sulfide toxicity in this fast-delivery, single-shot experimental paradigm. Nitrite anion was shown to rapidly produce NO in the bloodstream, as judged by the appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin, together amounting to less than 5% of the total hemoglobin present. Sulfide-intoxicated mice were neither helped by the supplemental administration of 100% oxygen nor were there any detrimental effects. Compared to cyanide-intoxicated mice, animals surviving sulfide intoxication exhibited very short knockdown times (if any) and full recovery was extremely fast (∼15 min) irrespective of whether sodium nitrite was administered. Behavioral experiments testing the ability of mice to maintain balance on a rotating cylinder showed no motor impairment up to 24 h post sulfide exposure. It is argued that antagonism of sulfide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity of nitrite rather than formation of methemoglobin.

  15. Isolation and Identification of Nitrite- oxidizing Bacteria

    Institute of Scientific and Technical Information of China (English)

    Yulong; CHEN; Wenyong; TAN; Da; YANG

    2015-01-01

    In order to select the strain that can degrade nitrite,we use the screening plate with nitrite as the sole nitrogen source to select the strain with ability to degrade nitrite,and get a strain with nitrite degrading capacity from the silt of shrimp farming pond in Hepu City,Guangxi Zhuang Autonomous Region. By identifying the strain from colony morphology,physiological and biochemical characteristics and 16 S r RNA sequence,we finally get a bacteria strain that can degrade nitrite,and this strain can grow well on the culture medium with nitrite concentration of 2 g / L. Based on morphology,nitrogen source requirements and evolutionary tree analysis of the above 16 S r RNA sequence,it is found that this strain belongs to Pannonibacter phragmitetus. According to the screening location,it is named HPPP007 strain.

  16. Fucoidan Extracts Ameliorate Acute Colitis.

    Science.gov (United States)

    Lean, Qi Ying; Eri, Rajaraman D; Fitton, J Helen; Patel, Rahul P; Gueven, Nuri

    2015-01-01

    Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn's disease, are an important cause of morbidity and impact significantly on quality of life. Overall, current treatments do not sustain a long-term clinical remission and are associated with adverse effects, which highlight the need for new treatment options. Fucoidans are complex sulphated, fucose-rich polysaccharides, found in edible brown algae and are described as having multiple bioactivities including potent anti-inflammatory effects. Therefore, the therapeutic potential of two different fucoidan preparations, fucoidan-polyphenol complex (Maritech Synergy) and depyrogenated fucoidan (DPF) was evaluated in the dextran sulphate sodium (DSS) mouse model of acute colitis. Mice were treated once daily over 7 days with fucoidans via oral (Synergy or DPF) or intraperitoneal administration (DPF). Signs and severity of colitis were monitored daily before colons and spleens were collected for macroscopic evaluation, cytokine measurements and histology. Orally administered Synergy and DPF, but not intraperitoneal DPF treatment, significantly ameliorated symptoms of colitis based on retention of body weight, as well as reduced diarrhoea and faecal blood loss, compared to the untreated colitis group. Colon and spleen weight in mice treated with oral fucoidan was also significantly lower, indicating reduced inflammation and oedema. Histological examination of untreated colitis mice confirmed a massive loss of crypt architecture and goblet cells, infiltration of immune cells and oedema, while all aspects of this pathology were alleviated by oral fucoidan. Importantly, in this model, the macroscopic changes induced by oral fucoidan correlated significantly with substantially decreased production of at least 15 pro-inflammatory cytokines by the colon tissue. Overall, oral fucoidan preparations significantly reduce the inflammatory pathology associated with DSS-induced colitis and could therefore represent

  17. 21 CFR 573.700 - Sodium nitrite.

    Science.gov (United States)

    2010-04-01

    ... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and fish in accordance with the following prescribed conditions: (a) It is used or intended for use alone as a preservative and color fixative in canned pet food containing fish, meat, and fish and...

  18. Dextran-based microspheres as controlled delivery systems for proteins

    NARCIS (Netherlands)

    Vlugt-Wensink, K.D.F.

    2007-01-01

    Dextran-based microspheres as controlled delivery systems for proteins Dextran based microspheres are investigated as controlled delivery system for proteins. Microspheres were prepared by polymerization of dex-HEMA in an aqueous two-phase system of dex-HEMA and PEG. Protein loaded microspheres are

  19. Orally delivered β-glucans aggravate dextran sulfate sodium (DSS)-induced intestinal inflammation.

    Science.gov (United States)

    Heinsbroek, Sigrid E M; Williams, David L; Welting, Olaf; Meijer, Sybren L; Gordon, Siamon; de Jonge, Wouter J

    2015-12-01

    β-Glucans have beneficial health effects due to their immune modulatory properties. Oral administration of β-glucans affects tumour growth, microbial infection, sepsis, and wound healing. We hypothesized that pre-treatment with orally delivered soluble and particulate β-glucans could ameliorate the development of aggravate dextran sulfate sodium (DSS) induced intestinal inflammation. To study this, mice were orally pre-treated with β-glucans for 14 days. We tested curdlan (a particulate β-(1,3)-glucan), glucan phosphate (a soluble β-(1,3)-glucan), and zymosan (a particle made from Saccharomyces cerevisiae, which contains around 55% β-glucans). Weight loss, colon weight, and feces score did not differ between β-glucan and vehicle treated groups. However, histology scores indicated that β-glucan-treated mice had increased inflammation at a microscopic level suggesting that β-glucan treatment worsened intestinal inflammation. Furthermore, curdlan and zymosan treatment led to increased colonic levels of inflammatory cytokines and chemokines, compared to vehicle. Glucan phosphate treatment did not significantly affect cytokine and chemokine levels. These data suggest that particulate and soluble β-glucans differentially affect the intestinal immune responses. However, no significant differences in other clinical colitis scores between soluble and particulate β-glucans were found in this study. In summary, β-glucans aggravate the course of dextran sulfate sodium (DSS)-induced intestinal inflammation at the level of the mucosa.

  20. PREPARATION AND ADSORBABILITY OF DEXTRAN MICROSPHERES WITH UNIFORM DIAMETER

    Institute of Scientific and Technical Information of China (English)

    Ri-sheng Yao; Wen-xia Gao; Jing Sun; Ya-hua You

    2005-01-01

    The method of preparing uniform dextran microspheres with a narrow diameter distribution was introduced and the adsorbability of these microspheres was evaluated. The microspheres were prepared in W/O microemulsion using 0.5% dextran solution as the aqueous phase and n-hexane as the oil phase. Characteristics of the prepared dextran microspheres were examined with laser light blocking technique, optical microscope and ultraviolet spectrometer. The results show that the prepared dextran microspheres have uniform morphology and narrow diameter distribution, nearly 92% of them having a diameter of 56.6 μm. In vitro evaluation of adsorbability, wet dextran microspheres have good adsorption of 98.32 mg/g of model drug methylene blue in 20.86 mg/L methylene blue solution at 25℃. The adsorption of dried dextran microspheres under the same condition is 132.15 mg/g, which is even higher. And the adsorbability of dextran microspheres has significant relationship with the concentration of methylene blue and temperature. The adsorbability is better at lower temperature and higher concentration of methylene blue.

  1. Nanoparticles of hydrophobically modified dextrans as potential drug carrier systems.

    Science.gov (United States)

    Aumelas, A; Serrero, A; Durand, A; Dellacherie, E; Leonard, M

    2007-09-01

    Nanoparticles combining a hydrophobically modified dextran core and a polysaccharide surface coverage were elaborated. Their suitability for applications like drug delivery was evaluated. The selected polysaccharide, dextran, was chemically modified by the covalent attachment of hydrocarbon groups (aliphatic or aromatic) via the formation of ether links. According to the extent of modification, either water-soluble or water-insoluble dextran derivatives were obtained. The latter exhibited solubility in organic solvents like tetrahydrofuran or dichloromethane saturated with water. Water-soluble dextran derivatives were used as polymeric surfactants for the control of nanoparticles surface characteristics. Nanoparticles were prepared either by o/w emulsion or solvent-diffusion methods. The size and surface properties of dextran nanoparticles were correlated to processing conditions. The stability of colloidal suspensions was examined as a function of ionic strength and related to the particle surface characteristics. The redispersability of freeze-dried suspensions without the addition of cryoprotectant was demonstrated. Finally, the degradability of modified dextrans was compared to that of starting dextran, after enzymatic hydrolysis in the presence of dextranase.

  2. Oat β-glucan ameliorates dextran sulfate sodium (DSS)-induced ulcerative colitis in mice.

    Science.gov (United States)

    Liu, Bo; Lin, Qinlu; Yang, Tao; Zeng, Linna; Shi, Limin; Chen, Yaya; Luo, Feijun

    2015-11-01

    Ulcerative colitis is a major inflammatory bowel disease (IBD), characterized by inflammation within the gastrointestinal tract through chronic or relapsing immune system activation. The aim of this study is to investigate the potential protective effect of oat β-glucan (βG) against colitis induced by DSS in mice. Eighty mice were randomly divided into the control group (no DSS, no βG), DSS group (DSS only), DSS + L-βG group (DSS plus 500 mg per kg βG), and DSS + H-βG group (DSS plus 1000 mg per kg βG). Compared with the DSS group, administration of βG significantly reduced clinical symptoms with less weight loss, diarrhea and shortening of the colon, the severity of colitis was significantly inhibited as evidenced by the reduced disease activity index (DAI) and degree of histological damage in colon. Moreover, treatment with βG not only decreased myeloperoxidase activity (MPO), and nitric oxide (NO) and malondialdehyde (MDA) levels, but also inhibited mRNA and protein expression of pro-inflammatory factors such as TNF-α, IL-1β, IL-6 and iNOS. This suggests that oat βG in diet might exhibit an anti-inflammatory function against colitis through inhibition of expression of pro-inflammatory factors.

  3. Nitrite complexes of uranium and thorium.

    Science.gov (United States)

    Dulong, Florian; Pouessel, Jacky; Thuéry, Pierre; Berthet, Jean-Claude; Ephritikhine, Michel; Cantat, Thibault

    2013-03-25

    The first examples of inorganic nitrite complexes of the natural actinides are described, including the structures of the homoleptic thorium(IV) [PPh(4)](2)[Th(NO(2))(6)] and the uranyl(VI) [PPh(4)](2)[UO(2)(NO(2))(4)] complexes; the nitrite ligand can adopt two different coordination modes in the coordination sphere of the uranyl ion and is unstable towards reduction.

  4. Biodegradable nanoparticles made from polylactide-grafted dextran copolymers.

    Science.gov (United States)

    Nouvel, C; Raynaud, J; Marie, E; Dellacherie, E; Six, J-L; Durand, A

    2009-02-15

    Polysaccharide-covered polyester nanoparticles were prepared using the emulsion/solvent evaporation process. The core of the nanoparticles was made either of PLA or of a blend of polylactide and polylactide-grafted dextran copolymer in various proportions. The surface of the nanoparticles was covered by dextran chains via the use of water-soluble polylactide-grafted dextrans as polymeric stabilizers during the emulsification step. The characteristics of the nanoparticles (size, surface coverage, thickness of superficial layer, colloidal stability) were correlated to the structural parameters (length and number of polylactide grafts) of the copolymers as well as to their surface active properties. The complete biodegradability of the nanoparticles was evaluated by considering the rate of hydrolysis of polylactide grafts in phosphate buffer and the rate of enzymatic degradation of dextran backbone by dextranase.

  5. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA)

    OpenAIRE

    Susann Neiser; Koskenkorva, Taija S.; Katrin Schwarz; Maria Wilhelm; Susanna Burckhardt

    2016-01-01

    Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various int...

  6. Dextran sulfate inhibits acute Toxoplama gondii infection in pigs

    OpenAIRE

    2016-01-01

    Background Toxoplasma gondii is a highly prevalent protozoan that can infect all warm-blooded animals, including humans. Its definitive hosts are Felidae and its intermediate hosts include various other mammals and birds, including pigs. It is found in the meat of livestock which is a major source of human infection. Hence the control of toxoplasmosis in pigs is important for public health. We previously showed that dextran sulfate (DS), especially DS10 (dextran sulfate MW 10 kDa), is effecti...

  7. Nitrate decreases xanthine oxidoreductase-mediated nitrite reductase activity and attenuates vascular and blood pressure responses to nitrite

    Directory of Open Access Journals (Sweden)

    Célio Damacena-Angelis

    2017-08-01

    Full Text Available Nitrite and nitrate restore deficient endogenous nitric oxide (NO production as they are converted back to NO, and therefore complement the classic enzymatic NO synthesis. Circulating nitrate and nitrite must cross membrane barriers to produce their effects and increased nitrate concentrations may attenuate the nitrite influx into cells, decreasing NO generation from nitrite. Moreover, xanthine oxidoreductase (XOR mediates NO formation from nitrite and nitrate. However, no study has examined whether nitrate attenuates XOR-mediated NO generation from nitrite. We hypothesized that nitrate attenuates the vascular and blood pressure responses to nitrite either by interfering with nitrite influx into vascular tissue, or by competing with nitrite for XOR, thus inhibiting XOR-mediated NO generation. We used two independent vascular function assays in rats (aortic ring preparations and isolated mesenteric arterial bed perfusion to examine the effects of sodium nitrate on the concentration-dependent responses to sodium nitrite. Both assays showed that nitrate attenuated the vascular responses to nitrite. Conversely, the aortic responses to the NO donor DETANONOate were not affected by sodium nitrate. Further confirming these results, we found that nitrate attenuated the acute blood pressure lowering effects of increasing doses of nitrite infused intravenously in freely moving rats. The possibility that nitrate could compete with nitrite and decrease nitrite influx into cells was tested by measuring the accumulation of nitrogen-15-labeled nitrite (15N-nitrite by aortic rings using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS. Nitrate exerted no effect on aortic accumulation of 15N-nitrite. Next, we used chemiluminescence-based NO detection to examine whether nitrate attenuates XOR-mediated nitrite reductase activity. Nitrate significantly shifted the Michaelis Menten saturation curve to the right, with a 3-fold increase in

  8. pH dependence of copper geometry, reduction potential, and nitrite affinity in nitrite reductase.

    NARCIS (Netherlands)

    Jacobson, F.; Pistorius, A.M.A.; Farkas, D.; Grip, W.J. de; Hansson, O.; Sjolin, L.; Neutze, R.

    2007-01-01

    Many properties of copper-containing nitrite reductase are pH-dependent, such as gene expression, enzyme activity, and substrate affinity. Here we use x-ray diffraction to investigate the structural basis for the pH dependence of activity and nitrite affinity by examining the type 2 copper site and

  9. Sensing nitrite through a pseudoazurin-nitrite reductase electron transfer relay

    NARCIS (Netherlands)

    Astier, Y; Canters, GW; Davis, JJ; Hill, HAO; Verbeet, MP; Wijma, HJ

    2005-01-01

    Nitrite is converted to nitric oxide by haem or copper-containing enzymes in denitrifying bacteria during the process of denitrification. In designing an efficient biosensor, this enzymic turnover must be quantitatively assessed. The enzyme nitrite reductase from Alcaligenes faecalis contains a redo

  10. Immobilized carboxymethylated dextran coatings for enhanced ELISA.

    Science.gov (United States)

    Liberelle, Benoît; Merzouki, Abderrazzak; De Crescenzo, Gregory

    2013-03-29

    We here report the development of a new generation of enzyme-linked immunosorbent assay (ELISA) that takes advantage of a low-fouling carboxymethylated dextran (CMD) layer chemically grafted on ELISA wells. In our approach, the overnight capture antibody adsorption step found in classical ELISA was replaced by a covalent attachment step to the CMD layer completed in 15 min. As a model, the potential of our approach was highlighted using commercially available anti-human epidermal growth factor (EGF) antibodies to quantify EGF present in various samples. Of interest, the grafted CMD layer was found to be as efficient as the commonly used bovine serum albumine (BSA) to reduce non-specific adsorption, thus eliminating the need of a time-consuming BSA blocking step normally required in classical ELISA. Our results demonstrated similar specificity, affinity, and intra- and inter-assay variations regardless of the diluent used in the assay (BSA-based diluent or protein-free buffer solution) when compared to standard ELISA. Finally, accuracy and precision of the CMD-based ELISA were verified by a spike and recovery test. Dilutions of recombinant human EGF in serum from healthy human volunteers showed almost-perfect linearity and mean recovery rates ranging between 90 and 110%.

  11. Spectroscopic study of copper(II) complexes with carboxymethyl dextran and dextran sulfate

    Science.gov (United States)

    Glišić, S.; Nikolić, G.; Cakić, M.; Trutić, N.

    2015-07-01

    The copper(II) ion complexes with carboxymethyl dextran (CMD) and dextran sulfate (DS) were studied by different methods. Content of copper was determined by atomic absorption spectroscopy. It was found that copper : ligand mole ratio (Cu : CMD) is 1 : 2, and Cu : DS is 1 : 1 by mole ratio method. Spectrophotometric parameters of synthesized compounds are characteristic for Cu(II) ion in octahedral ( O h ) coordination. Analyzing of FTIR spectra in ν(C=O) vibration region has showed that -COOH group acts as bidentate ligand, while the compounds of Cu(II) with DS copper ions are in the region of four oxygen atoms of two adjacent sulfo groups. The presence of crystalline water was determined by isotopic substitution of H2O molecules with D2O molecules. Comparison of spectra recorded at room (RT) and liquid nitrogen temperature (LNT) has enabled detection bands of water molecules libration indicating that they are coordinated complementing coordination sphere of Cu(II) ions to six. The complexes are of Cu(II) · (CMD)2 · (H2O)2 or Cu(II) · DS · (H2O)2 type. The similarities of the γ(C-H) range in a part of FTIR spectra indicate that there is no difference in the conformation of the 4 C 1 glucopyranose (Glc) unit CMD and DS synthesized Cu(II) complexes.

  12. Hypoxia tolerance, nitric oxide, and nitrite

    DEFF Research Database (Denmark)

    Fago, Angela; Jensen, Frank Bo

    2015-01-01

    Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia ...... of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals....... survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance...

  13. Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

    Directory of Open Access Journals (Sweden)

    Sirada Srihirun

    Full Text Available BACKGROUND: Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated. METHODOLOGY/FINDING: Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes. CONCLUSION: Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

  14. Chemically modified field effect transistors with nitrite or fluoride selectivity

    NARCIS (Netherlands)

    Antonisse, Martijn M.G.; Snellink-Ruël, Bianca H.M.; Engbersen, Johan F.J.; Reinhoudt, David N.

    1998-01-01

    Polysiloxanes with different types of polar substituents are excellent membrane materials for nitrite and fluoride selective chemically modified field effect transistors (CHEMFETs). Nitrite selectivity has been introduced by incorporation of a cobalt porphyrin into the membrane; fluoride selectivity

  15. Chemically modified field effect transistors with nitrite or fluoride selectivity

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Ruel, Bianca H.M.; Engbersen, Johannes F.J.; Reinhoudt, David

    1998-01-01

    Polysiloxanes with different types of polar substituents are excellent membrane materials for nitrite and fluoride selective chemically modified field effect transistors (CHEMFETs). Nitrite selectivity has been introduced by incorporation of a cobalt porphyrin into the membrane; fluoride selectivity

  16. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Neiser, Susann; Koskenkorva, Taija S; Schwarz, Katrin; Wilhelm, Maria; Burckhardt, Susanna

    2016-07-21

    Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3) and an enzyme-linked immunosorbent assay (ELISA) were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000) does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the mechanisms that may

  17. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA

    Directory of Open Access Journals (Sweden)

    Susann Neiser

    2016-07-01

    Full Text Available Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR, the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3 and an enzyme-linked immunosorbent assay (ELISA were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000 does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the

  18. Nitrite disrupts multiple physiological functions in aquatic animals

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2003-01-01

    nitrite-induced vasodilation (possibly via nitric oxide generated from nitrite) that is countered by increased cardiac pumping to re-establish blood pressure. Nitrite can form and/or mimic nitric oxide and thereby interfere with processes regulated by this local hormone. Steroid hormone synthesis may...... species and in some cases also within species. Rainbow trout fall into two groups with regard to susceptibility and physiological response. These two groups are not related to sex but show significant different nitrite uptake rates....

  19. New Collagen-Dextran-Zinc Oxide Composites for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Georgeta Păunica-Panea

    2016-01-01

    Full Text Available The goal of this paper was the design, development, and characterization of some new composites, based on collagen and dextran as natural polymers and zinc oxide as antimicrobial, to be used in wound healing. Collagen hydrogels with various concentrations of dextran and zinc oxide were investigated in terms of rheological analysis. The spongious composites, obtained by freeze-drying of hydrogels, were evaluated by morphology (SEM, water uptake, and biological (enzymatic biodegradation analysis. All the results were strongly influenced by the nature and concentration of composite components. Based on the performances of the hydrogels, stationary rheometry, porous structure, morphology, and biological behavior, the antimicrobial spongious composite based on collagen and dextran with 50% ZnO were the most promising for future applications in wound dressing and a biomaterial with high potential in skin regeneration.

  20. Nitrite maxima in the Northern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sankaranarayanan, V.N.; DeSousa, S.N.; Fondekar, S.P.

    There are 2 nitrite maxima in the Northern Arabian Sea, one at the thermocline depth and the other at depths between 300 and 500 m. The 2nd maximum is more prominent in the northeastern part of the Arabian Sea. The 1st maximum is associated...

  1. SPECTROPHOTOMETRIC DETERMINATION OF NITRITE BY ITS ...

    African Journals Online (AJOL)

    Preferred Customer

    The main sources of nitrite ion in unpolluted surface waters are the processes of organic matter mineralization and .... H2SO4 solution 3 M were transferred into a quartz cell. ..... Cai, X.; Li, P.; Zhao, Z. Fenxi Huaxue 1987, 15, 971. 7. Davis, J.

  2. Nitrite oxidation in the Namibian oxygen minimum zone.

    Science.gov (United States)

    Füssel, Jessika; Lam, Phyllis; Lavik, Gaute; Jensen, Marlene M; Holtappels, Moritz; Günter, Marcel; Kuypers, Marcel M M

    2012-06-01

    Nitrite oxidation is the second step of nitrification. It is the primary source of oceanic nitrate, the predominant form of bioavailable nitrogen in the ocean. Despite its obvious importance, nitrite oxidation has rarely been investigated in marine settings. We determined nitrite oxidation rates directly in (15)N-incubation experiments and compared the rates with those of nitrate reduction to nitrite, ammonia oxidation, anammox, denitrification, as well as dissimilatory nitrate/nitrite reduction to ammonium in the Namibian oxygen minimum zone (OMZ). Nitrite oxidation (≤372 nM NO(2)(-) d(-1)) was detected throughout the OMZ even when in situ oxygen concentrations were low to non-detectable. Nitrite oxidation rates often exceeded ammonia oxidation rates, whereas nitrate reduction served as an alternative and significant source of nitrite. Nitrite oxidation and anammox co-occurred in these oxygen-deficient waters, suggesting that nitrite-oxidizing bacteria (NOB) likely compete with anammox bacteria for nitrite when substrate availability became low. Among all of the known NOB genera targeted via catalyzed reporter deposition fluorescence in situ hybridization, only Nitrospina and Nitrococcus were detectable in the Namibian OMZ samples investigated. These NOB were abundant throughout the OMZ and contributed up to ~9% of total microbial community. Our combined results reveal that a considerable fraction of the recently recycled nitrogen or reduced NO(3)(-) was re-oxidized back to NO(3)(-) via nitrite oxidation, instead of being lost from the system through the anammox or denitrification pathways.

  3. Generation of nitric oxide from nitrite by carbonic anhydrase:

    DEFF Research Database (Denmark)

    Aamand, Rasmus; Dalsgaard, Thomas; Jensen, Frank Bo;

    2009-01-01

    bicarbonate and nitrite, we hypothesized that CA uses nitrite as a substrate to produce the potent vasodilator nitric oxide (NO) to increase local blood flow to metabolically active tissues. Here we show that CA readily reacts with nitrite to generate NO, particularly at low pH, and that the NO produced...

  4. A comparison of analytic procedures for measurement of fractional dextran clearances

    NARCIS (Netherlands)

    Hemmelder, MH; de Jong, PE; de Zeeuw, D

    1998-01-01

    Fractional dextran clearances have been extensively used to study glomerular size selectivity. We report on an analysis of different laboratory procedures involved in measuring fractional dextran clearances. The deproteinization of plasma samples by 20% trichloroacetic acid (TCA) revealed a protein

  5. Biodistribution of ~(99)Tc~m Labelled Dextran Conjugates for Sentinel Lymph Node Detection

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Mannosylated dextran conjugates showed high receptor affinity to the receptors on the surface of macrophages in the lymph node. 99Tcm labelled mannosylated dextran conjugates could be used for sentinel lymph node (SLN) detection. In this paper,

  6. A comparison of analytic procedures for measurement of fractional dextran clearances

    NARCIS (Netherlands)

    Hemmelder, MH; de Jong, PE; de Zeeuw, D

    1998-01-01

    Fractional dextran clearances have been extensively used to study glomerular size selectivity. We report on an analysis of different laboratory procedures involved in measuring fractional dextran clearances. The deproteinization of plasma samples by 20% trichloroacetic acid (TCA) revealed a protein

  7. Structural and biocompatibility properties of dextran from Weissella cibaria JAG8 as food additive.

    Science.gov (United States)

    Tingirikari, Jagan Mohan Rao; Kothari, Damini; Shukla, Rishikesh; Goyal, Arun

    2014-09-01

    Dextran produced from Weissella cibaria JAG8 was purified and characterized. The molecular mass of dextran as determined by the gel filtration and copper bicinchoninate method was approximately, 800 kDa. Monosaccharide analysis revealed that the polysaccharide comprised only glucose units. Dynamic light scattering study confirmed the mono-disperse nature of dextran with hydrodynamic radius of 900 nm. Surface morphology study of dextran by scanning electron microscopy showed the porous web like structure. Cytotoxicity studies on human cervical cancer (HeLa) cell line showed non-toxic and biocompatible nature of dextran. The relative browning for dextran from W. cibaria JAG8 was similar to commercial prebiotic Nutraflora P-95 and 3-fold lower than Raftilose P-95. Synthesis of dextran by dextransucrase treated, sucrose-supplemented skimmed milk revealed the promising potential of dextran as a food additive.

  8. Bioavailability of ketoprofen from orally administered ketoprofen-dextran ester prodrugs in the pig

    DEFF Research Database (Denmark)

    Larsen, C.; Jensen, Bodil Hamborg; Olesen, H. P.

    1991-01-01

    The bioavailability of ketoprofen after oral administration of aqueous solutions of various ketoprofen-dextran ester prodrugs in pigs was assessed. Conjugates derived from dextran fractions in the molecular weight range 10,000-500,000 were employed. Compared to the administration of an oral......-dextran esters. Thus, the present study adds support to a more versatile application of the dextran ester prodrug approach to providing selective colon delivery of drugs possessing a carboxylic acid functional group....

  9. Adult respiratory distress syndrome complicating intravenous infusion of low-molecular weight dextran.

    Science.gov (United States)

    Taylor, M A; DiBlasi, S L; Bender, R M; Santoian, E C; Cha, S D; Dennis, C A

    1994-07-01

    Respiratory failure is one of the most uncommon and serious adverse drug reactions. Low-molecular-weight-dextran (Dextran-40) is a useful adjunctive anti-platelet agent in the setting of coronary angioplasty and intracoronary stent placement. We report the occurrence of the adult respiratory distress syndrome following intravenous infusion of Dextran-40.

  10. More complications in patients with septic shock treated with dextran compared with crystalloids

    DEFF Research Database (Denmark)

    Rasmussen, Anders Mølgaard; Jakobsen, Rasmus; Strøm, Thomas;

    2015-01-01

    of patients admitted to our intensive care unit with septic shock and treated with dextran-70 in the period from 1 January 2009 to 31 December 2009. The controls were included from 1 March 2012 to 28 February 2013 when dextran-70 was replaced with crystalloids. RESULTS: There were 91 patients in the dextran...

  11. Removal of methyl violet dye by adsorption onto N-benzyltriazole derivatized dextran

    DEFF Research Database (Denmark)

    Cho, Eunae; Tahir, Muhammad Nazir; Kim, Hwanhee

    2015-01-01

    In this work, N-benzyltriazole derivatized dextran was evaluated for its potential as a novel carbohydrate-based adsorbent for the removal of methyl violet dye from water. The modified dextran was synthesized by a click reaction of pentynyl dextran and benzyl azide, and the structure...

  12. Dextran-modified iron oxide nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Jií; Hradil

    2007-01-01

    [1]Anger,S.,Caldwell,K.,Mehnert,W.,& Muller,R.(1999).Coating of nanoparticles:Analysis of adsorption using sedimentation field-flow fractionation(SdFFF).Proceedings of International Symposium of Controlled Release of Bioactivated Materials,26,599-600.[2]Bonnemain,B.(1998).Superparamagnetic agents in magnetic resonance imaging:Physicochemical characteristics and clinical applications-A review.Journal of Drug Targeting,6(3),167-174.[3]Bootz,A.,Vogel,V.,Schubert,D.,& Kreuter,J.(2004).Comparison of scanning electron microscopy,dynamic light scattering and analytical ultracentrifugation for the sizing of poly(butyl cyanoacrylate) nanoparticles.European Journal of Pharmaceutics and Biopharmaceutics,57(2),369-375.[4]Browarzik,D.(1997).Continuous kinetics of dextran degradation.Journal of Macromolecular Science Pure and Applied Chemistry,34(3),397-404.[5]Cabasso,I.,& Yuan,Y.(1996).Nanoparticles in polymer and polymer dendrimers.In J.Fendler & I.Dekany (Eds.),NATO ASI Series.Part 18Nanoparticles in Solids and Solutions (pp.131-153).[6]Chastellain,M.,Petri,A.,& Hofmann,H.(2004).Particle size investigation of a multistep synthesis of PVA coated superparamagnetic nanoparticles.Journal of Colloid Interface Science,278(2),353-360.[7]Chmela,E.,Tijssen,R.,Blom,M.T.,Gardeniers,H.J.G.E.,& van den Berg,A.(2002).A chip system for size separation of macromolecules and particles by hydrodynamic chromatography.Analytical Chemistry,74(14),3470-3475.[8]Confer,D.R.,& Logan,B.E.(1997).Molecular weight distribution of hydrolysis product during the biodegradation of model macromolecules in suspended and biofilm cultures.Ⅱ:Dextran and dextrin.Water Research,31(9),2137-2145.[9]Griffiths,C.H.,O'Horo,M.P.,& Smith,T.W.(1979).The structure,magnetic characterization and oxidation of colloidal iron dispersions.Journal of Applied Physics,50(11),7108-7115.[10]Gupta,A.K.,& Gupta,M.(2005).Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications.Biomaterials,26

  13. Microbial dextran-hydrolyzing enzymes: fundamentals and applications.

    Science.gov (United States)

    Khalikova, Elvira; Susi, Petri; Korpela, Timo

    2005-06-01

    Dextran is a chemically and physically complex polymer, breakdown of which is carried out by a variety of endo- and exodextranases. Enzymes in many groups can be classified as dextranases according to function: such enzymes include dextranhydrolases, glucodextranases, exoisomaltohydrolases, exoisomaltotriohydrases, and branched-dextran exo-1,2-alpha-glucosidases. Cycloisomalto-oligosaccharide glucanotransferase does not formally belong to the dextranases even though its side reaction produces hydrolyzed dextrans. A new classification system for glycosylhydrolases and glycosyltransferases, which is based on amino acid sequence similarities, divides the dextranases into five families. However, this classification is still incomplete since sequence information is missing for many of the enzymes that have been biochemically characterized as dextranases. Dextran-degrading enzymes have been isolated from a wide range of microorganisms. The major characteristics of these enzymes, the methods for analyzing their activities and biological roles, analysis of primary sequence data, and three-dimensional structures of dextranases have been dealt with in this review. Dextranases are promising for future use in various scientific and biotechnological applications.

  14. 21 CFR 520.1182 - Iron dextran suspension.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Iron dextran suspension. 520.1182 Section 520.1182 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... dose dispenser. (2) Indications for use. For the prevention of iron deficiency anemia in baby pigs. (3...

  15. The investigation of Co(II-dextran complexes

    Directory of Open Access Journals (Sweden)

    Mitić Žarko J.

    2007-01-01

    Full Text Available Co(II ion complex compounds were synthesized with reduced dextran (RD in alkali solutions using CoCl2, 6H2O and isolated in the solid state. UV-VIS spectrophotometric investigations of Co(II complexes with reduced dextran showed that the complexation of Co(II ions begins at pH over 7. The formation of Co(II ion complexes with dextran monomer units was observed at pH 7-13. With increase in solution pH the light absorption maximum of complex solutions shifts to longer wavelengths (bat-hochromic shift compared with [Co(H2O6]2+ ion. Dextran complexes with Co(II ion are formed by the displacement of water molecules from the coordination sphere of cobalt by the OH ligand groups. The spectrophotometric parameters of the investigated complexes are characteristic of a Co(II ion in octahedral or distorted octahedral coordination with O ligand atoms.

  16. Dextran fractional clearance studies in acute dengue infection.

    Directory of Open Access Journals (Sweden)

    Julie Nguyen-Pouplin

    2011-08-01

    Full Text Available BACKGROUND: Although increased capillary permeability is the major clinical feature associated with severe dengue infections the mechanisms underlying this phenomenon remain unclear. Dextran clearance methodology has been used to investigate the molecular sieving properties of the microvasculature in clinical situations associated with altered permeability, including during pregnancy and in various renal disorders. In order to better understand the characteristics of the vascular leak associated with dengue we undertook formal dextran clearance studies in Vietnamese dengue patients and healthy volunteers. METHODOLOGY/PRINCIPAL FINDINGS: We carried out serial clearance studies in 15 young adult males with acute dengue and evidence of vascular leakage a during the phase of maximal leakage and b one and three months later, as well as in 16 healthy control subjects. Interestingly we found no difference in the clearance profiles of neutral dextran solutions among the dengue patients at any time-point or in comparison to the healthy volunteers. CONCLUSIONS/SIGNIFICANCE: The surface glycocalyx layer, a fibre-matrix of proteoglycans, glycosaminoglycans, and plasma proteins, forms a complex with the underlying endothelial cells to regulate plasma volume within circumscribed limits. It is likely that during dengue infections loss of plasma proteins from this layer alters the permeability characteristics of the complex; physical and/or electrostatic interactions between the dextran molecules and the glycocalyx structure may temporarily restore normal function, rendering the technique unsuitable for assessing permeability in these patients. The implications for resuscitation of patients with dengue shock syndrome (DSS are potentially important. It is possible that continuous low-dose infusions of dextran may help to stabilize the permeability barrier in patients with profound or refractory shock, reducing the need for repeated boluses, limiting the total

  17. Hypoxia tolerance, nitric oxide, and nitrite

    DEFF Research Database (Denmark)

    Fago, Angela; Jensen, Frank Bo

    2015-01-01

    Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia...... survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance...

  18. Comparative analysis of nitrite uptake and hemoglobin-nitrite reactions in erythrocytes: sorting out uptake mechanisms and oxygenation dependencies

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Rohde, Sabina

    2010-01-01

    Nitrite uptake into red blood cells (RBCs) precedes its intracellular reactions with hemoglobin (Hb) that forms nitric oxide (NO) during hypoxia. We investigated the uptake of nitrite and its reactions with Hb at different oxygen saturations (So2), using RBCs with (carp and rabbit) and without...... (hagfish and lamprey) anion exchanger-1 (AE1) in the membrane, with the aim to unravel the mechanisms and oxygenation dependencies of nitrite transport. Added nitrite rapidly diffused into the RBCs until equilibrium. The distribution ratio of nitrite across the membrane agreed with that expected from HNO2...... diffusion and AE1-mediated facilitated NO2- diffusion. Participation of HNO2 diffusion was emphasized by rapid transmembrane nitrite equilibration also in the natural AE1 knockouts. Following the equilibration, nitrite was consumed by reacting with Hb, which created a continued inward diffusion controlled...

  19. Myristica fragrans seed extract protects against dextran sulfate sodium-induced colitis in mice.

    Science.gov (United States)

    Kim, Hyojung; Bu, Youngmin; Lee, Beom-Joon; Bae, Jinhyun; Park, Sujin; Kim, Jinsung; Lee, Kyungjin; Cha, Jae-Myung; Ryu, Bongha; Ko, Seok-Jae; Han, Gajin; Min, Byungil; Park, Jae-Woo

    2013-10-01

    Nutmeg (seed of Myristica fragrans [MF]) is one of the most commonly used spices in the world and also a well-known herb for the treatment of various intestinal diseases, including colitis in traditional Korean medicine. The purpose of the current study was to investigate whether water extract of MF (MFE) can protect against dextran sulfate sodium (DSS) induced colitis in a mouse model. Colitis was induced by 5% DSS in balb/c mice. MFE (100, 300 or 1000 mg/kg) was orally administered to the mice twice a day for 7 days. Body weight, colon length, clinical score, and histological score were assessed to determine the effects on colitis. Proinflammatory cytokines (interferon-γ, tumor necrosis factor-α, interleukin [IL]-1β, and IL-6) were measured to investigate the mechanisms of action. MFE dose dependently inhibited the colon shortening and histological damage to the colon. However, it did not prevent weight loss. MFE also inhibited proinflammatory cytokines. The current results suggest that MFE ameliorates DSS-induced colitis in mice by inhibiting inflammatory cytokines. Further investigation, including the exact mechanisms is needed.

  20. Effects of ulinastatin in experimental colitis induced by dextran sulfate sodium in rats

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: Ulinastatin has been reported to be beneficial for maintenance of steroid-refractory inflammatory bowel disease (IBD), but the mechanism underlying remains uncertain. Leukocyte recruitment to inflammatory site plays an important role in the pathogenesis of IBD, analysis of leukocyte and endothelium interaction may provide new avenues for treatment of IBD. In this study, we evaluated the efficacy of Ulinastatin in dextran sulfate sodium (DSS) induced colitis rat model using intravital video microscopy. METHODS: Rats were given drinking water containing 3.5% (W/V) DSS for 10 days then 1% for 14 days. DSS induced colitis rats were treated Ulinastatin 3 000 unit*kg-1*d-1 via intraperitoneum during 1% DSS feeding. Controls received distilled water for 24 days. Body weight was determined for all groups. Colitis severity was assessed using histological scoring systems by H&E sections. Intravital microscopic techniques were used to quantitate leukocyte adhesion (LA), leukocyte emigration (LE) and venular protein leakage (VPL) in rat mesentery. RESULTS: DSS induced loss of body weight, whereas Ulinastatin-treated rat showed a significant increase in body weight. Histological analysis revealed improvement of colitis such as leukocyte infiltration, loss of goblet cells, transmural edema. DSS intake elicited increase in LA, LE, and VPL compared to control group. Ulinstatin significantly reversed the increase in LA, LE, and VPL induced by DSS. CONCLUSION: Administration of Ulinastatin effectively ameliorates experimental colitis by interfering with leukocyte recruitment, and may become a potential candidate for control of inflammation of IBD.

  1. Nitric oxide formation from nitrite in zebrafish

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2007-01-01

    nitrite levels for variable time periods, and changes in blood nitrosylhemoglobin (HbNO), methemoglobin (metHb), oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) were evaluated by spectral deconvolution. Blood HbNO (a biomarker of internal NO production) was low in controls, increased......, and the possibility that excess NO may inhibit mitochondrial respiration, whole animal routine oxygen consumption was not depressed....

  2. Nitrite in feed: From Animal health to human health

    Energy Technology Data Exchange (ETDEWEB)

    Cockburn, Andrew [Institute for Research on Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE17RU (United Kingdom); Brambilla, Gianfranco [Istituto Superiore di Sanità, Toxicological chemistry unit, Viale Regina Elena 299, 00161 Rome (Italy); Fernández, Maria-Luisa [Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ministerio de Ciencia e Innovación, Carretera de la Coruña, 28040 Madrid (Spain); Arcella, Davide [Unit on Data Collection and Exposure, European Food Safety Authority, Largo N. Palli 5/A43100 Parma (Italy); Bordajandi, Luisa R. [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy); Cottrill, Bruce [Policy Delivery Group, Animal Health and Welfare, ADAS, Wolverhampton (United Kingdom); Peteghem, Carlos van [University of Gent, Harelbekestraat 72, 9000 Gent (Belgium); Dorne, Jean-Lou, E-mail: jean-lou.dorne@efsa.europa.eu [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy)

    2013-08-01

    Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3 mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  3. Nitrite isotopes as tracers of marine N cycle processes

    Science.gov (United States)

    Casciotti, Karen L.

    2016-11-01

    Nitrite (NO2-) is a key intermediate in the marine nitrogen (N) cycle. It is produced and consumed throughout the ocean by the dominant processes driving the distribution, availability and speciation of N. However, the accumulation of nitrite is typically confined to depths near the base of the sunlit euphotic zone and in oxygen-deficient zones. These features are known as the primary and secondary nitrite maximum (PNM and SNM), respectively. The processes controlling nitrite accumulation in these features are not fully understood, but are thought to depend on the microbial community composition and its response to environmental conditions. A variety of approaches have been applied to understanding these features since their discovery, with the stable N and oxygen (O) isotope measurements of nitrite being added to this toolkit most recently. Large variations in nitrite N isotope ratios (15N/14N) and dramatic depletions in 15N contrast with more consistent nitrite O isotope ratios (18O/16O) in the SNM. These signals provide unique information about the mechanisms of nitrite consumption in the SNM. By contrast, nitrite in the PNM shows less variation in 15N/14N, but variations in 18O/16O that provide insight into the mechanisms and rates of N cycling there. This review presents a synthesis of nitrite isotope measurements in the marine environment, highlighting the insights that have been gained from these measurements. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  4. Biomass Industrial Effluent Effect on Carbohydrates, Aminoacids, Nitrite and Nitrite Enzyme Activities of Arachis hypogaea L

    Institute of Scientific and Technical Information of China (English)

    PC Nagajyoti; N Dinakarc; S Suresh; Y Udaykiran; C Suresh; T N V K V Prasad; T Damodharam

    2009-01-01

    The objectives of the present investigations are to see the effects of biomass power plant effluent on the carbohydrates, aminoacids, nitrite and nitrite enzyme activitiesand proline of Arachis hypogaea L. vat TCGS 320 under controlled pot culture methods. Plants were cultivated with 25, 50, 75 and 100% of the effluent and a control without the effluent. The treatment of the crop with 25% of the effluent has shown stimulatory effect on all the biochemical parameters studied. Carbohydrates, starch, aminoacids, protein, nitrate and nitrite reductase enzymatic activities have increased in 10, 15, 20 DAS (days after sowing). In 25 and 30 DAS all biochemical parameters have decreased, due to environmental factors (rainfall, temperature, humidity, etc.). The present investigation clearly indicated that the biomass power plant effluent has stimulatory effect on all the biochemical contents at lower concentration, and at higher concentration they have deleterious effects.

  5. Methaemoglobinaemia due to amyl nitrite inhalation: a case report.

    Science.gov (United States)

    Machabert, R; Testud, F; Descotes, J

    1994-05-01

    Methaemoglobinaemia is a potential toxic effect of aliphatic nitrites which are increasingly abused by male homosexuals and drug addicts because of marked vasodilating properties ('poppers'). In most instances, severe complications were described following the ingestion of large quantities of amyl, butyl or isobutyl nitrites. A deficiency in NADH-dependent haemoglobin reductase in some patients has been noted. This is the first report of symptomatic methaemoglobinaemia following the inhalation of amyl nitrite.

  6. Size-controlled nanoassemblies based on cyclodextrin-modified dextrans.

    Science.gov (United States)

    Wintgens, Véronique; Nielsen, Thorbjørn Terndrup; Larsen, Kim Lambertsen; Amiel, Catherine

    2011-09-09

    Nanoassemblies formed by host/guest interactions between two polymers in aqueous media are studied. Two types of polymers with the same dextran backbone are modified with adamantyl or βCD groups. The sizes of the spontaneously formed nanoassemblies depend on the βCD:Ada ratio and on the total concentration and composition of the mixtures. The results can be rationalized by assuming a core/shell structure of the nanoassemblies, the core resulting from associative phase separation of the two polymers and being stabilized by an external shell made of Ada-grafted dextran and containing ions adsorbed from the solution. Hydrophobic compounds such as benzophenone can be incorporated efficiently without inducing changes in properties of the nanoassemblies.

  7. Effect of Molecular Weight and Molar Ratio of Dextran on Self-Assembly of Dextran Stearate Polymeric Micelles as Nanocarriers for Etoposide

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2012-01-01

    Full Text Available Amphiphilic polymer surfactants are composed of hydrophilic and hydrophobic polymers and are widely used in targeted drug delivery. The purpose of this study was the evaluation of the effect of molecular weight and molar ratio of dextran on physicochemical properties of dextran stearate polymeric micelles. Dextran stearate was synthesized by acylation of dextran with stearoyl chloride. Etoposide loaded polymeric micelles were prepared by dialysis method. The resulting micelles were evaluated for particle size, zeta potential, critical micelle concentration (CMC, drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of micelles were studied in CT-26 colorectal carcinoma cell line. Molecular weight and molar ratio of dextran-stearate were impressive on zeta potential, CMC, drug loading capacity, and release efficiency. Unlike polymer molecular weight, molar ratio of stearate had a significant effect on cytotoxicity and particle size of etoposide loaded micelles. Although molecular weight of dextran had no significant effect on cytotoxicity of micelles on CT-26 cells, it had drastic attributes for stability of polymeric micelles. Consequently, both variables of molecular weight of dextran and molar ratio of stearate should be taken into account to have a stable and effective micelle of dextran-stearate.

  8. Unraveling the origin of the nitrite-mediated hypoxic vasodilation

    DEFF Research Database (Denmark)

    Fago, Angela; Dalsgaard, T.; Simonsen, U.

    2007-01-01

    Circulating nitrite has recently emerged as an important physiological metabolite that contributes to increase vasodilation during tissue hypoxia. Using a wire myograph, we have investigated how the nitrite-dependent vasodilation in rat aortic rings is controlled by oxygen tension, norepinephrine...... are sufficient to induce NO-mediated vasodilation independently of the nitrite reductase activities here investigated. These results further indicate that the vasoactive effect of nitrite is intrinsic to the vessel and may be due to S-nitrosothiols formed within the arterial smooth muscle....

  9. A novel nitrite biosensor based on conductometric electrode modified with cytochrome c nitrite reductase composite membrane.

    Science.gov (United States)

    Zhang, Zhiqiang; Xia, Siqing; Leonard, Didier; Jaffrezic-Renault, Nicole; Zhang, Jiao; Bessueille, François; Goepfert, Yves; Wang, Xuejiang; Chen, Ling; Zhu, Zhiliang; Zhao, Jianfu; Almeida, M Gabriela; Silveira, Célia M

    2009-02-15

    A conductometric biosensor for nitrite detection was developed using cytochrome c nitrite reductase (ccNiR) extracted from Desulfovibrio desulfuricans ATCC 27774 cells immobilized on a planar interdigitated electrode by cross-linking with saturated glutaraldehyde (GA) vapour in the presence of bovine serum albumin, methyl viologen (MV), Nafion, and glycerol. The configuration parameters for this biosensor, including the enzyme concentration, ccNiR/BSA ratio, MV concentration, and Nafion concentration, were optimized. Various experimental parameters, such as sodium dithionite added, working buffer solution, and temperature, were investigated with regard to their effect on the conductance response of the biosensor to nitrite. Under the optimum conditions at room temperature (about 25 degrees C), the conductometric biosensor showed a fast response to nitrite (about 10s) with a linear range of 0.2-120 microM, a sensitivity of 0.194 microS/microM [NO(2)(-)], and a detection limit of 0.05 microM. The biosensor also showed satisfactory reproducibility (relative standard deviation of 6%, n=5). The apparent Michaelis-Menten constant (K(M,app)) was 338 microM. When stored in potassium phosphate buffer (100mM, pH 7.6) at 4 degrees C, the biosensor showed good stability over 1 month. No obvious interference from other ionic species familiar in natural waters was detected. The application experiments show that the biosensor is suitable for use in real water samples.

  10. Origin, causes and effects of increased nitrite concentrations in aquatic environments

    NARCIS (Netherlands)

    Philips, S.; Laanbroek, H.J.; Verstraete, W.

    2002-01-01

    Literature frequently mentions increased nitrite concentrations along with its inhibitory effect towards bacteria and aquatic life. Nitrite accumulation has been studied for decades, and although numerous causal factors have already been commented on in literature, the mechanism of nitrite

  11. Garlic oil as a modulating agent for oxidative stress and neurotoxicity induced by sodium nitrite in male albino rats.

    Science.gov (United States)

    Hassan, Hanaa A; Hafez, Hani S; Zeghebar, Fawzia E

    2010-07-01

    In the present study, we investigated the neurobiochemical alterations and oxidative stress induced by food preservative; sodium nitrite (NaNO2) as well as the role of the garlic oil in amelioration of the neurotoxicity in male albino rats. Serum and brain homogenates of the rats received NaNO2 (80 mg/kg body weight) for 3 months exhibited significant decrease in acetylcholine esterase (AChE) activity as well as the levels of phospholipids, total protein and the endogenous antioxidant system (glutathione; GSH and superoxide dismutase; SOD). In contrast, lactic dehydrogenase (LDH) activity, brain thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) levels were significantly increased. On the other hand, the oral administration of garlic oil (5 ml/kg body weight) daily for 3 months significantly improved the neurobiochemical disorders and inhibited the oxidative stress induced by NaNO2 ingestion. So, this study reveals the neural toxic effects of NaNO2 by exerting oxidative stress and retrograde the endogenous antioxidant system. However, garlic oil has a promising role in attenuating the obtained hazard effects of sodium nitrite by its high antioxidant properties which may eventually be related with the preservation of SOD activity and primary mitochondrial role against nitrite-induced neurotoxicity in rats.

  12. A method for synthesis and functionalization of ultrasmall superparamagnetic covalent carriers based on maghemite and dextran

    Energy Technology Data Exchange (ETDEWEB)

    Mornet, Stephane [Institut de Chimie de la Matiere Condensee de Bordeaux, CNRS UPR 9048, Universite Bordeaux-1, 87 avenue du Dr Albert Schweitzer, F-33608 Pessac, Cedex (France); Portier, Josik [Institut de Chimie de la Matiere Condensee de Bordeaux, CNRS UPR 9048, Universite Bordeaux-1, 87 avenue du Dr Albert Schweitzer, F-33608 Pessac, Cedex (France); Duguet, Etienne [Institut de Chimie de la Matiere Condensee de Bordeaux, CNRS UPR 9048, Universite Bordeaux-1, 87 avenue du Dr Albert Schweitzer, F-33608 Pessac, Cedex (France)]. E-mail: duguet@icmcb.u-bordeaux1.fr

    2005-05-15

    A new generation of susceptibility contrast agents for MRI and based on maghemite cores covalently bonded to dextran stabilizing macromolecules was investigated. The multistep preparation of these versatile ultrasmall superparamagnetic iron oxides (VUSPIO) consisted of colloidal maghemite synthesis, surface modification by aminopropylsilane groups, and coupling of partially oxidized dextran via Schiff's bases and secondary amine bonds. The dextran corona might be easily derivatized, e.g. by PEGylation.

  13. The role of nitrite in nitric oxide homeostasis

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2009-01-01

    -tolerant species. Nitrite-induced vasodilation is well documented, and many studies support a role of erythrocyte/hemoglobin-derived NO. Vasodilation can, however, also originate from nitrite reduction within the vessel wall, and at present there is no consensus regarding the relative importance of competing...

  14. Bidirectional catalysis by copper-containing nitrite reductase

    NARCIS (Netherlands)

    Wijma, HJ; Canters, GW; de Vries, S; Verbeet, MP

    2004-01-01

    The copper-containing nitrite reductase from Alcaligenes faecalis S-6 was found to catalyze the oxidation of nitric oxide to nitrite, the reverse of its physiological reaction. Thermodynamic and kinetic constants with the physiological electron donor pseudoazurin were determined for both directions

  15. Nitrate and nitrite in biology, nutrition and therapeutics

    NARCIS (Netherlands)

    Lundberg, J.O.; van Faassen, E.E.H.; Gladwin, M.T.; Ahluwalia, A.; Benjamin, N.

    2009-01-01

    Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia.

  16. The Impact of Nitrite on Aerobic Growth of Paracoccus denitrificans PD1222

    OpenAIRE

    Hartop, Katherine

    2014-01-01

    The effect of nitrite stress induced in Paracoccus denitrificans PD1222 was examined using additions of sodium nitrite to an aerobic bacterial culture. Nitrite generates a strong stress response in P. denitrificans, causing growth inhibition. This is dependent on both the concentration of nitrite present and the pH. The pH dependent effect of nitrite growth inhibition is likely a result of nitrite and free nitrous acid (FNA; pKa = 3.16) and subsequent reactive nitrogen oxides, ...

  17. Cellular interactions of lauric acid and dextran-coated magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Pallab [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Giri, Jyotsnendu [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Mumbai 400076 (India); Banerjee, Rinti [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Bellare, Jayesh [School of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai 400076 (India); Bahadur, Dhirendra [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Mumbai 400076 (India)]. E-mail: dhirenb@iitb.ac.in

    2007-04-15

    In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.

  18. Cellular interactions of lauric acid and dextran-coated magnetite nanoparticles

    Science.gov (United States)

    Pradhan, Pallab; Giri, Jyotsnendu; Banerjee, Rinti; Bellare, Jayesh; Bahadur, Dhirendra

    2007-04-01

    In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.

  19. Preparation of dextran immunological magnetic nanoparticles and their application to combined targeting carrier

    Institute of Scientific and Technical Information of China (English)

    李民勤; 徐慧显; 左榘; 姬昂; 何炳林; 庞雁; 黄建英; 牛瑞芳

    1996-01-01

    Superparamagnetic dextran nanoparticles were prepared by coprecipitation. Effects of concentration of dextran, amount of ironic salts, stirring speed, concentration of ammonium hydroxide and mole ratio of Fe3+/Fe2+ on the effective diameter of dextran magnetic nanopartides (DMNP) were studied. Dextran immunological magnetic nanoparticles (DIMNP) were formed by the reaction of the monoclonal anti-human mammary cancer antibody with DMNP oxidized by sodium periodate, and the properties of magnetic susceptibility, shape and retention of antibody activity were investigated. The in vitro cancer antigen binding ability of DIMNP was demonstrated by radioimmunoassay, and the in vivo magnetic localization and antibody targeting ability of radiolabeled DIMNP were studied.

  20. Determination of NO chemical affinities of benzyl nitrite in acetonitrile

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Xiaoqing ZHU; Jinpei CHENG

    2008-01-01

    There is an increasing interest in the study of NO chemical affinities of organic nitrites, for the bio-logical and physiological effects of organic nitrites seem to be due to their ability to release NO. In this paper, NO chemical affinities of ten substituted benzyl nitrites were determined by titration calorimetry combined with a ther-modynamic cycle in acetonitrile solution. The results show that ΔHhet(O-NO)s of benzyl nitrites are substan-tially larger than the corresponding ΔHhomo(O-NO)s, suggesting that these O-nitroso compounds much more easily release NO radicals by the O-NO bond homolytic cleavage. It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.

  1. Spectrophotometric determination of nitrite using salbutamol sulfate as a reagent

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Y.K.; Bhatt, P.N.

    1988-01-01

    A simple spectrophotometric method for the trace determination of nitrite (NO/sub 2//sup /minus//) is described. Nitrite is reacted with Salbutamol sulfate in acidic medium which gives a yellow color in alkaline medium (less than or equal to pH 7) and can be determined in the presence of several cations and anions. Beer's law is obeyed in the range of 1.8 to 27.6 ppm of nitrite with the molar absorptivity 1.8 /times/ 10/sup 3/ 1 /times/ mole /sup /minus/1/ /times/ cm/sup /minus/1/ at 410 nm. The proposed method can also be utilized for the determination of nitrate (NO/sub 3//sup /minus//) after its reduction to nitrite. The method has been applied for the determination of various samples containing traces of nitrite.

  2. EPR spectroscopy of nitrite complexes of methemoglobin.

    Science.gov (United States)

    Schwab, David E; Stamler, Jonathan S; Singel, David J

    2010-07-19

    The chemical interplay of nitrogen oxides (NO's) with hemoglobin (Hb) has attracted considerable recent attention because of its potential significance in the mechanism of NO-related vasoactivity regulated by Hb. An important theme of this interplay-redox coupling in adducts of heme iron and NO's-has sparked renewed interest in fundamental studies of FeNO(x) coordination complexes. In this Article, we report combined UV-vis and comprehensive electron paramagnetic resonance (EPR) spectroscopic studies that address intriguing questions raised in recent studies of the structure and affinity of the nitrite ligand in complexes with Fe(III) in methemoglobin (metHb). EPR spectra of metHb/NO(2)(-) are found to exhibit a characteristic doubling in their sharper spectral features. Comparative EPR measurements at X- and S-band frequencies, and in D(2)O versus H(2)O, argue against the assignment of this splitting as hyperfine structure. Correlated changes in the EPR spectra with pH enable complete assignment of the spectrum as deriving from the overlap of two low-spin species with g values of 3.018, 2.122, 1.45 and 2.870, 2.304, 1.45 (values for samples at 20 K and pH 7.4 in phosphate-buffered saline). These g values are typical of g values found for other heme proteins with N-coordinated ligands in the binding pocket and are thus suggestive of N-nitro versus O-nitrito coordination. The positions and shapes of the spectral lines vary only slightly with temperature until motional averaging ensues at approximately 150 K. The pattern of motional averaging in the variable-temperature EPR spectra and EPR studies of Fe(III)NO(2)(-)/Fe(II)NO hybrids suggest that one of two species is present in both of the alpha and beta subunits, while the other is exclusive to the beta subunit. Our results also reconfirm that the affinity of nitrite for metHb is of millimolar magnitude, thereby making a direct role for nitrite in physiological hypoxic vasodilation difficult to justify.

  3. Purification and characterization of assimilatory nitrite reductase from Candida utilis.

    Science.gov (United States)

    Sengupta, S; Shaila, M S; Rao, G R

    1996-07-01

    Nitrate assimilation in many plants, algae, yeasts and bacteria is mediated by two enzymes, nitrate reductase (EC 1.6.6.2) and nitrite reductase (EC 1.7.7.1). They catalyse the stepwise reduction of nitrate to nitrite and nitrite to ammonia respectively. The nitrite reductase from an industrially important yeast, Candida utilis, has been purified to homogeneity. Purified nitrite reductase is a heterodimer and the molecular masses of the two subunits are 58 and 66 kDa. The native enzyme exhibits a molecular mass of 126 kDa as analysed by gel filtration. The identify of the two subunits of nitrite reductase was confirmed by immunoblotting using antibody for Cucurbita pepo leaf nitrite reductase. The presence of two different sized transcripts coding for the two subunits was confirmed by (a) in vitro translation of mRNA from nitrate-induced C. utilis followed by immunoprecipitation of the in vitro translated products with heterologous nitrite reductase antibody and (b) Northern-blot analysis. The 66 kDa subunit is acidic in nature which is probably due to its phosphorylated status. The enzyme is stable over a range of temperatures. Both subunits can catalyse nitrite reduction, and the reconstituted enzyme, at a higher protein concentration, shows an activity similar to that of the purified enzyme. Each of these subunits has been shown to contain a few unique peptides in addition to a large number of common peptides. Reduced Methyl Viologen has been found to be as effective an electron donor as NADPH in the catalytic process, a phenomenon not commonly seen for nitrite reductases from other systems.

  4. Bifidobacterium breve attenuates murine dextran sodium sulfate-induced colitis and increases regulatory T cell responses.

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    Full Text Available While some probiotics have shown beneficial effects on preventing or treating colitis development, others have shown no effects. In this study, we have assessed the immunomodulating effects of two probiotic strains, Lactobacillus rhamnosus (L. rhamnosus and Bifidobacterium breve (B. breve on T cell polarization in vitro, using human peripheral blood mononuclear cells (PBMC, and in vivo, using murine dextran sodium sulfate (DSS colitis model. With respect to the latter, the mRNA expression of T cell subset-associated transcription factors and cytokines in the colon was measured and the T helper type (Th 17 and regulatory T cell (Treg subsets were determined in the Peyer's patches. Both L. rhamnosus and B. breve incubations in vitro reduced Th17 and increased Th2 cell subsets in human PBMCs. In addition, B. breve incubation was also able to reduce Th1 and increase Treg cell subsets in contrast to L. rhamnosus. In vivo intervention with B. breve, but not L. rhamnosus, significantly attenuated the severity of DSS-induced colitis. In DSS-treated C57BL/6 mice, intervention with B. breve increased the expression of mRNA encoding for Th2- and Treg-associated cytokines in the distal colon. In addition, intervention with B. breve led to increases of Treg and decreases of Th17 cell subsets in Peyer's patches of DSS-treated mice. B. breve modulates T cell polarization towards Th2 and Treg cell-associated responses in vitro and in vivo. In vivo B. breve intervention ameliorates DSS-induced colitis symptoms and this protective effect may mediated by its effects on the T-cell composition.

  5. Balsalazine decreases intestinal mucosal permeability of dextran sulfate sodium-induced colitis in mice

    Institute of Scientific and Technical Information of China (English)

    Xiao-chang LIU; Qiao MEI; Jian-ming XU; Jing HU

    2009-01-01

    Aim:To investigate the effect of balsalazine treatment on intestinal mucosal permeability in dextran sulfate sodium (DSS)-induced colitis and to determine the mechanism of the balsalazine-induced changes.Methods:Experimental colitis was induced in C57BL/6J mice by the administration of 5% DSS.Balsalazine was administered intragastrically at doses of 42,141,and 423 mg/kg.The disease activity index (DAI) score was evaluated and colon tissue was collected for the assessment of histological changes.The amount of malondialdehyde (MDA) in the colon was determined,along with the activity of myeloperoxidase (MPO),superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).Mucosa from the small intestine was collected to determine the levels of tumor necrosis factor (TNF)-α and interferon (IFN)-Y.The mucosa was ultrastructurally examined with transmission electron microscopy and intestinal permeability was assayed using Evans blue.Results:Balsalazine was found to reduce the DAI score and the histological index (HI) score,decrease the MDA content and the activity of MPO,and increase the activity of SOD and GSH-Px in colitis mice.At the same time,balsalazine ameliorated microvillus and tight junction structure,resulting in a decrease in the amount of Evans blue permeating into the intestinal wall and the levels of TNF-α and IFN-Y in colitis mice.Conclusion:In colitis mice,the anti-colitis effect of balsalazine results in a decrease in intestinal mucosal permeability.The mechanism of this effect is partly associated with balsalazine's antioxidative and anti-inflammatory effects.

  6. Anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium-induced colitis of rats

    Institute of Scientific and Technical Information of China (English)

    Ping Zheng; Feng-Li Niu; Wen-Zhong Liu; Yao Shi; Lun-Gen Lu

    2005-01-01

    AIM: To investigate the anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium (DSS)-induced colitis of rats.METHODS: Acute colitis was induced by giving 2% DSS orally in drinking water for 8 d. Twenty-six male rats were randomized into oxymatrine-treated group (group A, 10rats), DSS control (group B, 10 rats) and normal control (group C, 6 rats). The rats in group A were injected from d 1 to 11 and drank 2% DSS solution from d 4 to 11.The rats in group B were treated with 0.9% saline in an equal volume as group A and drank 2% DSS solution from d 4 to 11. The rats in group C were treated with 0.9% saline as group B from d 1 to 11 and drank water normally. Diarrhea and bloody stool as well as colonic histology were observed. The levels of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by ELISA, and nuclear factor-κB (NF-κB)activity and the expression of inter-cellular adhesion molecule-1 (ICAM-1) in colonic mucosa were detected by immunohistochernistry method.RESULTS: Compared with DSS control group, the inflammatory symptoms and histological damages of colonic mucosa in oxymatrine-treated group were significantly improved, the serum levels of TNF-α, IL-6, and the expression of NF-κB, ICAM-1 in colonic mucosa were significantly reduced.CONCLUSION: The fact that oxymatrine can reduce the serum levels of TNF-α, IL-6, and the expression of NF-κB and ICAM-1 in colonic mucosa in DSS-induced colitis of rats indicates that oxymatrine may ameliorate the colonic inflammation and thus alleviate diarrhea and bloody stool.

  7. Immobilization of Lipase by Covalent Binding on Crosslinked Ally Dextran

    Institute of Scientific and Technical Information of China (English)

    WangChen; SongGuoqiang; 等

    1998-01-01

    Lipase was immobilized by covalent binding on crosslinked allyl dextran using SESA as coupling agent.It is shown that this immobilization approach is an efficient one for lipase.The activity of the immobilized lipase can reach to 300-450U/g(dry weight).It exhibits good temperature stability,can retain 88% activity after being incubated at 70℃ for 2h.Special effects will be expected from our immobilized lipase in its applications in organic media due to the nature of the support.

  8. Impact of mitochondria on nitrite metabolism in HL-1 cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Peter eDungel

    2013-05-01

    Full Text Available Apart from ATP synthesis mitochondria have many other functions, one being nitrite reductase activity. NO released from nitrite has been shown to protect the heart from ischemia/reperfusion injury in a cGMP-dependent manner. However, the exact impact of mitochondria on the release of NO from nitrite in cardiomyocytes is not completely understood. Besides mitochondria, a number of non-mitochondrial metalloproteins have been suggested to facilitate this process. The aim of this study was to investigate the impact of mitochondria on the bioactivation of nitrite in HL-1 cardiomyocytes.The levels of nitrosyl complexes of hemoglobin (NO-Hb and cGMP levels were measured by electron spin resonance spectroscopy and enzyme immunoassay. In addition the formation of free NO was determined by confocal microscopy as well as intracellular nitrite and S-nitrosothiols by chemoluminescence analysis. NO was released from nitrite in cell culture in an oxygen dependent manner. Application of specific inhibitors of the respiratory chain, p450, NO synthases and xanthine oxidoreductase showed that all four enzymatic systems are involved in the release of NO, but more than 50% of NO is released via the mitochondrial pathway. Only NO released by mitochondria activated cGMP synthesis. Cardiomyocytes co-cultured with red blood cells (RBC competed with RBC for nitrite, but free NO was detected only in HL-1 cells suggesting that RBC are not a source of NO in this model. Apart from activation of cGMP synthesis, NO formed in HL-1 cells diffused out of the cells and formed NO-Hb complexes. In addition nitrite was converted by HL-1 cells to S-nitrosyl complexes. In HL-1 cardiomyocytes, several enzymatic systems are involved in nitrite reduction to NO but only the mitochondrial pathway of NO release activates cGMP synthesis. Our data suggest that this pathway may be a key regulator of myocardial contractility especially under hypoxic conditions.

  9. Control factors of partial nitritation for landfill leachate treatment

    Institute of Scientific and Technical Information of China (English)

    LIANG Zhu; LIU Jun-xin

    2007-01-01

    Anaerobic ammonium oxidation (ANAMMOX) technology has potential technical superiority and economical efficiency for the nitrogen removal from landfill leachate, which contains high-strength ammonium nitrogen (NH4+-N) and refractory organics. To complete the ANAMMOX process, a preceding partial nitritation step to produce the appropriate ratio of nitrite/ammonium is a key stage. The objective of this study was to determine the optimal conditions to acquire constant partial nitritation for landfill leachate treatment, and a bench scale fixed bed bio-film reactor was used in this study to investigate the effects of the running factors on the partial nitritation. The results showed that both the dissolved oxygen (DO) concentration and the ammonium volumetric loading rate (Nv) had effects on the partial nitritation. In the controlling conditions with a temperature of 30±1℃, Nv of 0.2-1.0 kg NH4+-N/(m3·d), and DO concentration of 0.8-2.3 mg/L, the steady partial nitritation was achieved as follows: more than 94% partial nitritation efficiency (nitrite as the main product), 60%-74% NH4+-N removal efficiency, and NO2--N/NH4+-N ratio (concentration ratio) of 1.0-1.4 in the effluent.The impact of temperature was related to Nv at certain DO concentration, and the temperature range of 25-30℃ was suitable for treating high strength ammonium leachate. Ammonium-oxidizing bacteria (AOB) could be acclimated to higher FA (free ammonium) in the range of 122-224 mg/L. According to the denaturing gradient gel electrophoresis analysis result of the bio-film in the reactor, there were 25 kinds of 16S rRNA gene fragments, which indicated that abundant microbial communities existed in the bio-film, although high concentrations of ammonium and FA may inhibit the growth of the nitrite-oxidizing bacteria (NOB) and other microorganisms in the reactor.

  10. [Cardiovascular effect of solcoseryl with low molecular dextran in normal late pregnancy].

    Science.gov (United States)

    Schwarz, R; Retzke, U; Wilken, H P

    1977-01-01

    By means of quantitative sphygmometry and the unbloody recording of arterial blood pressure the hemodynamic effect of an infusion of Solcoseryl in combination with low molecular dextrane on the maternal cardiovascular system in 9 normotensive healthy late pregnant women is examined. Solcoseryl causes no improvement of the cardiovascular effects known for low molecular dextrane.

  11. Development of monoclonal antibody-based sandwich ELISA for detection of dextran.

    Science.gov (United States)

    Wang, Sheng-Yu; Li, Zhe; Wang, Xian-Jiang; Lv, Sha; Yang, Yun; Zeng, Lian-Qiang; Luo, Fang-Hong; Yan, Jiang-Hua; Liang, Da-Feng

    2014-10-01

    Dextran as anti-nutritional factor is usually a result of bacteria activity and has associated serial problems during the process stream in the sugar industry and in medical therapy. A sensitive method is expected to detect dextran quantitatively. Here we generated four monoclonal antibodies (MAbs) against dextran using dextran T40 conjugated with bovine serum albumin (BSA) as immunogen in our lab following hybridoma protocol. Through pairwise, an MAb named D24 was determined to be conjugated with horseradish peroxidase (HRP) and was used in the establishment of a sensitive sandwich enzyme-linked immunosorbent assay (ELISA) method for determination of dextran, in which MAb D9 was chosen as a capture antibody. The detection limit and working scope of the developed sandwich ELISA method were 3.9 ng/mL and 7.8-500 ng/mL with a correlation coefficient of 0.9909. In addition, the cross-reaction assay demonstrated that the method possessed high specificity with no significant cross-reaction with dextran-related substances, and the recovery rate ranged from 96.35 to 102.00%, with coefficient of variation ranging from 1.58 to 6.94%. These results indicated that we developed a detection system of MAb-based sandwich ELISA to measure dextran and this system should be a potential tool to determine dextran levels.

  12. Mechanisms of the ultrasound-mediated intracellular delivery of liposomes and dextrans.

    Science.gov (United States)

    Afadzi, Mercy; Strand, Sabina P; Nilssen, Esben A; Måsøy, Svein-Erik; Johansen, Tonni F; Hansen, Rune; Angelsen, Bjørn A; de L Davies, Catharina

    2013-01-01

    The mechanism involved in the ultrasoundenhanced intracellular delivery of fluorescein-isothiocyanate (FITC)-dextran (molecular weight 4 to 2000 kDa) and liposomes containing doxorubicin (Dox) was studied using HeLa cells and an ultrasound transducer at 300 kHz, varying the acoustic power. The cellular uptake and cell viability were measured using flow cytometry and confocal microscopy. The role of endocytosis was investigated by inhibiting clathrin- and caveolae-mediated endocytosis, as well as macropinocytosis. Microbubbles were found to be required during ultrasound treatment to obtain enhanced cellular uptake. The percentage of cells internalizing Dox and dextran increased with increasing mechanical index. Confocal images and flow cytometric analysis indicated that the liposomes were disrupted extracellularly and that released Dox was taken up by the cells. The percentage of cells internalizing dextran was independent of the molecular weight of dextrans, but the amount of the small 4-kDa dextran molecules internalized per cell was higher than for the other dextrans. The inhibition of endocytosis during ultrasound exposure resulted in a significant decrease in cellular uptake of dextrans. Therefore, the improved uptake of Dox and dextrans may be a result of both sonoporation and endocytosis.

  13. Mussel-inspired modification of dextran for protein-resistant coatings of titanium oxide.

    Science.gov (United States)

    Park, Jae Yoon; Kim, Jee Seon; Nam, Yoon Sung

    2013-09-12

    Surface modification of inorganic materials to prevent non-specific protein adsorption is critically important for developing a biocompatible materials' platform for medical implantation, diagnostics, and therapeutics. Here we report mussel-inspired chemical modification of dextran for anti-fouling coatings of metal oxide. Catechols are conjugated to dextran via a carbamate ester linkage, producing catechol-grafted dextran with a grafting density of 7.3 mol.%. Titanium dioxide (TiO₂) is coated with the catechol-grafted dextran, and the anti-fouling effect of dextran coatings is examined by using the adsorption of human serum albumin. The mussel-inspired dextran coatings show excellent resistance to non-specific protein adsorption: the adsorption equilibrium constant (K) is 0.69 Lg(-1) for dextran-coated TiO₂ while that for pristine TiO₂ surface is 3.53 Lg(-1). This study suggests that catechol-grafted dextran is a promising material for effective anti-fouling coatings of implantable inorganic materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. The effect of hypertonic saline dextran solutions on hypoxic pulmonary vasoconstriction in anaesthetised piglets.

    Science.gov (United States)

    Bellezza, M; Kerbaul, F; Roussel, L; Imbert, M; Guidon, C

    2002-10-01

    Hypoxic pulmonary vasoconstriction (HPV) is a regulatory mechanism by which blood is diverted from poorly ventilated to better ventilated areas of the lung. The aim of the present study was to assess the extent to which hypertonic saline dextran and dextran solutions modify the magnitude of HPV during isovolumic haemodilution in intact acutely instrumented piglets. Eighteen large white piglets were anesthetised and assigned to two groups. Mean pulmonary arterial pressure (PAP) and cardiac output (Q), systemic arterial pressure and left arterial pressure (LAP) were measured. A decrease in Q was obtained by reducing venous return. This enabled measurement of transpulmonary pressures (mean PAP minus LAP) at four levels of Q in hyperoxia (inspiratory oxygen fraction (FiO2)=0.4) then in hypoxia (Fi,O2=0.1) in the two groups before blood soustraction (10 mL x kg(-1)) and after loading with sodium chloride (NaCl) 7.5% and dextran 6% or with dextran 6% alone. Dextran alone led to a decrease in mean PAP-LAP/Q values, and NaCl with dextran was associated with a significant shift of mean PAP-LAP/Q plots to higher pressures in hypoxia. Hypertonic saline dextran solution, as replacement fluid in isovolaemic haemodilution increased the magnitude of hypoxic pulmonary vasoconstriction, whereas dextran solution reduced it.

  15. In situ production and analysis of Weissella confusa dextran in wheat sourdough.

    Science.gov (United States)

    Katina, Kati; Maina, Ndegwa Henry; Juvonen, Riikka; Flander, Laura; Johansson, Liisa; Virkki, Liisa; Tenkanen, Maija; Laitila, Arja

    2009-10-01

    Several lactic acid bacteria belonging to the genera Leuconostoc, Lactobacillus, and Weissella have been introduced to wheat sourdough baking for in situ production of exopolysaccharides. This is considered a novel method for improving the shelf-life, volume and nutritional value of bread without additives. However, in situ production of exopolysaccharides during sourdough fermentation is challenged by simultaneous acidification due to metabolic activities of the bacteria, which may significantly diminish the positive technological impact of exopolysaccharides. In this study, the growth, activity and in situ production of dextran by Weissella confusa VTT E-90392 in wheat sourdoughs were investigated. Furthermore, the influence of dextran-enriched sourdoughs, at the addition level of 43%, on the subsequent bread quality was established. W. confusa efficiently produced dextran from the added sucrose in wheat sourdough without strong acid production. A new specific enzyme-assisted method for in situ analysis of dextran in sourdoughs was developed. With this method, we could for the first time proof significant (11-16 g/kg DW) production of polymeric dextran in sourdoughs. Concomitant formation of shorter isomaltooligosaccharides by W. confusa was also detected. The produced dextran significantly increased the viscosity of the sourdoughs. Application of dextran-enriched sourdoughs in bread baking provided mildly acidic wheat bread with improved volume (up to 10%) and crumb softness (25-40%) during 6 days of storage. Hence, W. confusa is a promising new strain for efficient in situ production of dextrans and isomaltooligosaccharides in sourdoughs without strong acidification.

  16. Dextran vesicular carriers for dual encapsulation of hydrophilic and hydrophobic molecules and delivery into cells.

    Science.gov (United States)

    Pramod, P S; Takamura, Kathryn; Chaphekar, Sonali; Balasubramanian, Nagaraj; Jayakannan, M

    2012-11-12

    Dextran vesicular nanoscaffolds were developed based on polysaccharide and renewable resource alkyl tail for dual encapsulation of hydrophilic and hydrophobic molecules (or drugs) and delivery into cells. The roles of the hydrophobic segments on the molecular self-organization of dextran backbone into vesicles or nanoparticles were investigated in detail. Dextran vesicles were found to be a unique dual carrier in which water-soluble molecules (like Rhodamine-B, Rh-B) and polyaromatic anticancer drug (camptothecin, CPT) were selectively encapsulated in the hydrophilic core and hydrophobic layer, respectively. The dextran vesicles were capable of protecting the plasma-sensitive CPT lactone pharmacophore against the hydrolysis by 10× better than the CPT alone in PBS. The aliphatic ester linkage connecting the hydrophobic tail with dextran was found to be cleaved by esterase under physiological conditions for fast releasing of CPT or Rh-B. Cytotoxicity of the dextran vesicle and its drug conjugate were tested on mouse embryonic fibroblast cells (MEFs) using MTT assay. The dextran vesicular scaffold was found to be nontoxic to living cells. CPT loaded vesicles were found to be 2.5-fold more effective in killing fibroblasts compared to that of CPT alone in PBS. Confocal microscopic images confirmed that both Rh-B and CPT loaded vesicles to be taken up by fibroblasts compared to CPT alone, showing a distinctly perinuclear localization in cells. The custom designed dextran vesicular provides new research opportunities for dual loading and delivering of hydrophilic and hydrophobic drug molecules.

  17. Injectable dextran hydrogels fabricated by metal-free click chemistry for cartilage tissue engineering.

    Science.gov (United States)

    Wang, Xiaoyu; Li, Zihan; Shi, Ting; Zhao, Peng; An, Kangkang; Lin, Chao; Liu, Hongwei

    2017-04-01

    Injectable dextran-based hydrogels were prepared for the first time by bioorthogonal click chemistry for cartilage tissue engineering. Click-crosslinked injectable hydrogels based on cyto-compatible dextran (Mw=10kDa) were successfully fabricated under physiological conditions by metal-free alkyne-azide cycloaddition (click) reaction between azadibenzocyclooctyne-modified dextran (Dex-ADIBO) and azide-modified dextran (Dex-N3). Gelation time of these dextran hydrogels could be regulated in the range of approximately 1.1 to 10.2min, depending on the polymer concentrations (5% or 10%) and ADIBO substitution degree (DS, 5 or 10) of Dex-ADIBO. Rheological analysis indicated that the dextran hydrogels were elastic and had storage moduli from 2.1 to 6.0kPa with increasing DS of ADIBO from 5 to 10. The in vitro tests revealed that the dextran hydrogel crosslinked from Dex-ADIBO DS 10 and Dex-N3 DS 10 at a polymer concentration of 10% could support high viability of individual rabbit chondrocytes and the chondrocyte spheroids encapsulated in the hydrogel over 21days. Individual chondrocytes and chondrocyte spheroids in the hydrogel could produce cartilage matrices such as collagen and glycosaminoglycans. However, the chondrocyte spheroids produced a higher content of matrices than individual chondrocytes. This study indicates that metal-free click chemistry is effective to produce injectable dextran hydrogels for cartilage tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Modeling the Impact of Ingoing Sodium Nitrite, Sodium Ascorbate, and Residual Nitrite Concentrations on Growth Parameters of Listeria monocytogenes in Cooked, Cured Pork Sausage.

    Science.gov (United States)

    King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Seman, Dennis L; Sindelar, Jeffrey J

    2016-02-01

    Sodium nitrite has been identified as a key antimicrobial ingredient to control pathogens in ready-to-eat (RTE) meat and poultry products, including Listeria monocytogenes. This study was designed to more clearly elucidate the relationship between chemical factors (ingoing nitrite, ascorbate, and residual nitrite) and L. monocytogenes growth in RTE meats. Treatments of cooked, cured pork sausage (65% moisture, 1.8% salt, pH 6.6, and water activity 0.98) were based on response surface methodology with ingoing nitrite and ascorbate concentrations as the two main factors. Concentrations of nitrite and ascorbate, including star points, ranged from 0 to 352 and 0 to 643 ppm, respectively. At one of two time points after manufacturing (days 0 and 28), half of each treatment was surface inoculated to target 3 log CFU/g of a five-strain L. monocytogenes cocktail, vacuum packaged, and stored at 7°C for up to 4 weeks. Growth of L. monocytogenes was measured twice per week, and enumerations were used to estimate lag time and growth rates for each treatment. Residual nitrite concentrations were measured on days 0, 4, 7, 14, 21, and 28, and nitrite depletion rate was estimated by using first-order kinetics. The response surface methodology was used to model L. monocytogenes lag time and growth rate based on ingoing nitrite, ascorbate, and the residual nitrite remaining at the point of inoculation. Modeling results showed that lag time was impacted by residual nitrite concentration remaining at inoculation, as well as the squared term of ingoing nitrite, whereas growth rate was affected by ingoing nitrite concentration but not by the remaining residual nitrite at the point of inoculation. Residual nitrite depletion rate was dependent upon ingoing nitrite concentration and was only slightly affected by ascorbate concentration. This study confirmed that ingoing nitrite concentration influences L. monocytogenes growth in RTE products, yet residual nitrite concentration contributes

  19. Terpene and dextran renewable resources for the synthesis of amphiphilic biopolymers.

    Science.gov (United States)

    Alvès, Marie-Hélène; Sfeir, Huda; Tranchant, Jean-François; Gombart, Emilie; Sagorin, Gilles; Caillol, Sylvain; Billon, Laurent; Save, Maud

    2014-01-13

    The present work shows the synthesis of amphiphilic polymers based on the hydrophilic dextran and the hydrophobic terpenes as renewable resources. The first step concerns the synthesis of functional terpene molecules by thiol-ene addition chemistry involving amino or carboxylic acid thiols and dihydromyrcenol terpene. The terpene-modified polysaccharides were subsequently synthesized by coupling the functional terpenes with dextran. A reductive amination step produced terpene end-modified dextran with 94% of functionalization, while the esterification step produced three terpene-grafted dextrans with a number of terpene units per dextran of 1, 5, and 10. The amphiphilic renewable grafted polymers were tested as emulsifiers for the stabilization of liquid miniemulsion of terpene droplets dispersed in an aqueous phase. The average hydrodynamic diameter of the stable droplets was observed at about 330 nm.

  20. Generation of nitric oxide from nitrite by carbonic anhydrase

    DEFF Research Database (Denmark)

    Aamand, Rasmus; Dalsgaard, Thomas; Jensen, Frank B;

    2009-01-01

    In catalyzing the reversible hydration of CO2 to bicarbonate and protons, the ubiquitous enzyme carbonic anhydrase (CA) plays a crucial role in CO2 transport, in acid-base balance, and in linking local acidosis to O2 unloading from hemoglobin. Considering the structural similarity between...... in the reaction induces vasodilation in aortic rings. This reaction occurs under normoxic and hypoxic conditions and in various tissues at physiological levels of CA and nitrite. Furthermore, two specific inhibitors of the CO2 hydration, dorzolamide and acetazolamide, increase the CA-catalyzed production...... of vasoactive NO from nitrite. This enhancing effect may explain the known vasodilating effects of these drugs and indicates that CO2 and nitrite bind differently to the enzyme active site. Kinetic analyses show a higher reaction rate at high pH, suggesting that anionic nitrite participates more effectively...

  1. [Spectrophotofluorimetric determination of trace nitrite with safranine T].

    Science.gov (United States)

    Dong, Cun-zhi; Wu, Wei-dong

    2003-02-01

    A new fluorescence quenching method has been developed to determine nitrite in water samples. The method is based on the diazo-reaction between nitrite ion and safranine T in hydrochloric acid medium. The fluorescence intensity was measured at excitation and emission wavelengths of 525.0 and 556.0 nm, respectively. The optimum experimental conditions have been confirmed and the concentration of hydrochloric acid was 0.096 mol.L-1; the reaction time was 10 min. Under the selected conditions, the relationship was obtained between the fluorescence intensity and nitrite concentration in the range 4-200 x 10(-9) g.mL-1 NO2-. The detection limit was 4 x 10(-9) g.mL-1 NO2-. The method was applied to determine trace nitrite in water samples. The mechanism involved in the reaction was discussed.

  2. Performance of denitrifying microbial fuel cell with biocathode over nitrite

    Directory of Open Access Journals (Sweden)

    Zhao eHuimin

    2016-03-01

    Full Text Available Microbial fuel cell (MFC with nitrite as an electron acceptor in cathode provided a new technology for nitrogen removal and electricity production simultaneously. The influences of influent nitrite concentration and external resistance on the performance of denitrifying MFC were investigated. The optimal effectiveness were obtained with the maximum total nitrogen (TN removal rate of 54.80±0.01 g m-3 d-1. It would be rather desirable for the TN removal than electricity generation at lower external resistance. Denaturing gradient gel electrophoresis suggested that Proteobacteria was the predominant phylum, accounting for 35.72%. Thiobacillus and Afipia might benefit to nitrite removal. The presence of nitrifying Devosia indicated that nitrite was oxidized to nitrate via a biochemical mechanism in the cathode. Ignavibacterium and Anaerolineaceae was found in the cathode as a heterotrophic bacterium with sodium acetate as substrate, which illustrated that sodium acetate in anode was likely permeated through proton exchange membrane to the cathode .

  3. Mobile Nitrite Wastewater Treatment System (NWTS) User Data Package

    Science.gov (United States)

    1997-09-01

    NAVAL FACILITIES ENGINEERING SERVICE CENTER Port Hueneme, California 93043-4370 USER DATA PACKAGE UDP-2003-ENV MOBILE NITRITE WASTEWATER TREATMENT ...TITLE AND SUBTITLE MOBILE NITRITE WASTEWATER TREATMENT SYSTEMS (NWTS) USER DATA PACKAGE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...SYSTEM (NWTS) USER DATA PACKAGE by T. Richard Lee, Ph.D R. T. Kudo Joseph McGillian* *Naval Surface Warfare Center Cardcrock Division Pmladclpma, PA

  4. A Review of Nitrate and Nitrite Toxicity in Foods

    Directory of Open Access Journals (Sweden)

    Mir-Jamal Hosseini

    2016-03-01

    Full Text Available Agricultural advancement and population growth have prompted increases in food supplies, and higher crop yields have been made possible through the application of fertilizers. Large quantities of livestock and poultry on farms, along with the accumulation of biomass and agricultural residues, can cause contamination of ground water resources and other water sanitation concerns in both developing and developed countries. Nitrate is mainly used as a fertilizer in agriculture, and because of its high solubility in water, it can create biological problems in the environment. High usage of nitrite in the food industry as a preservative, flavor enhancer, antioxidant, and color stabilizing agent can cause human exposure to this toxic compound. Nitrite is 10 times as toxic as nitrate in humans. Nitrate is converted to nitrite and nitrosamine compounds in the human stomach, which can lead to bladder cancer. In this review, sources of nitrate and nitrite exposure were investigated. Furthermore, the review evaluates standard levels of nitrate and nitrite in different foods, and acceptable daily doses of these compounds in various countries. Finally, we discuss valid methods of nitrate and nitrite identification and removal in foods.

  5. Mutagenicity of some alkyl nitrites used as recreational drugs

    Energy Technology Data Exchange (ETDEWEB)

    Dunkel, V.C.; Cameron, T.P. (National Institute of Health, Bethesda (USA)); Rogers-Back, A.M.; Lawlor, T.E.; Harbell, J.W. (Microbiological Associates Inc., Rockville, MD (USA))

    1989-01-01

    When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK {plus minus} and Salmonell typhimurium mutagenicity assays. One chemical, n-amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n-butyl, isobutyl, iso-amyl, sec-butyl, and n-propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.

  6. 3-hydroxyflavone-bovine serum albumin interaction in Dextran medium

    Directory of Open Access Journals (Sweden)

    Voicescu Mariana

    2015-01-01

    Full Text Available Spectroscopic analysis of a bioactive flavonol, 3-Hydroxyflavone (3-HF, in systems based on Dextran 70 (Dx70 (an important bio-relevant polysacharide and Bovine Serum Albumin (BSA (a carrier protein, have been studied by fluorescence and circular dichroism. Changes produced by different concentrations of Dx70 on the fluorescent characteristics of 3-HF, and on the excited - state intramolecular proton transfer (ESIPT process were studied. The influence of 3-HF binding and of Dx70 on the secondary structure of BSA were investigated by circular dichroism spectroscopy. The influence of temperature (30-80°C range on the intrinsic Tryptophan fluorescence in 3-HF/BSA/Dx70 systems, was investigated. The results are discussed with relevance to 3-HF as a sensitive fluorescence probe for exploring flavone-protein interaction in plasma expander media and also for its biological evaluation.

  7. Dextran sulfate sodium (DSS)-induced colitis in mice.

    Science.gov (United States)

    Chassaing, Benoit; Aitken, Jesse D; Malleshappa, Madhu; Vijay-Kumar, Matam

    2014-02-04

    Inflammatory bowel diseases (IBD), mainly comprising ulcerative colitis and Crohn's Disease, are complex and multifactorial diseases with unknown etiology. For the past 20 years, to study human IBD mechanistically, a number of murine models of colitis have been developed. These models are indispensable tools to decipher underlying mechanisms of IBD pathogenesis as well as to evaluate a number of potential therapeutics. Among various chemically induced colitis models, the dextran sulfate sodium (DSS)-induced colitis model is widely used because of its simplicity and many similarities with human ulcerative colitis. This model has both advantages and disadvantages that must be considered when employed. This protocol describes the DSS-induced colitis model, focusing on details and factors that could affect DSS-induced pathology.

  8. Chitosan/dextran multilayer microcapsules for polyphenol co-delivery

    Energy Technology Data Exchange (ETDEWEB)

    Paini, Marco, E-mail: marco.paini@unige.it [Department of Civil, Chemical and Environmental Engineering, University of Genoa, via Opera Pia 15, 16145 Genoa (Italy); Research Center for Biologically Inspired Engineering in Vascular Medicine and Longevity (BELONG), Via Montallegro 1, 16145 Genoa (Italy); Aliakbarian, Bahar; Casazza, Alessandro A.; Perego, Patrizia [Department of Civil, Chemical and Environmental Engineering, University of Genoa, via Opera Pia 15, 16145 Genoa (Italy); Research Center for Biologically Inspired Engineering in Vascular Medicine and Longevity (BELONG), Via Montallegro 1, 16145 Genoa (Italy); Ruggiero, Carmelina; Pastorino, Laura [Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genoa, Via Opera Pia 13, 16145 Genoa (Italy)

    2015-01-01

    Polysaccharide-based nanostructured polymeric microcapsules were fabricated by the electrostatic layer-by-layer self-assembly technique and used to encapsulate mixtures of four different polyphenols in order to achieve their controlled release. The real-time fabrication of the dextran/chitosan multilayer was monitored by quartz crystal microbalance with dissipation monitoring, and the morphology of the nanostructured polymeric capsules was characterized by scanning electron microscopy. The polyphenol encapsulation was obtained by reversible permeability variation of the capsule shell in ethanol:water mixtures. The loading efficiency in different water:ethanol mixtures and the release rate in acidic conditions were characterized by UV spectroscopy and HPLC. The higher loading efficiency was obtained with an ethanol:water 35:65 phenolic solution, equal to 42.0 ± 0.6%, with a total release of 11.5 ± 0.7 mg of total polyphenols per 11.3 μL of microcapsules after 240 min of incubation in acidic environment. The results suggest that polysaccharide-based capsules can be successfully used to encapsulate and release low water-soluble molecules, such as polyphenols. - Highlights: • Chitosan/dextran nanocapsules were made by layer-by-layer self-assembly technique. • Different ethanol:water mixtures of four polyphenols were encapsulated. • An encapsulation efficiency of 42.0 ± 0.6% was obtained using ethanol:water 35:65. • Release profiles in acidic environment were monitored by UV spectroscopy and HPLC. • Nanocapsules had shown a complete release after 60 min in acidic environment.

  9. Tanshinone IIA Protects against Dextran Sulfate Sodium- (DSS-) Induced Colitis in Mice by Modulation of Neutrophil Infiltration and Activation.

    Science.gov (United States)

    Liu, Xiaowei; He, Haiyue; Huang, Tingting; Lei, Zhen; Liu, Fuquan; An, Guangyu; Wen, Tao

    2016-01-01

    Neutrophils play a critical role in the initiation and maintenance of intestinal inflammation. However, conventional neutrophil-targeted therapies can impair normal host defense. Tanshinone IIA has been recently revealed to act directly on neutrophils. Hence, we aimed at investigating whether Tanshinone IIA can protect against experimental colitis through modulation of neutrophils. We induced colitis in C57BL/6 mice by giving 3% dextran sulfate sodium (DSS) orally, and meanwhile, we treated mice daily with Tanshinone IIA intraperitoneally. The severity of colitis was evaluated by calculating disease activity index (DAI) and histological parameters. Neutrophil infiltration and activation in the colons of mice were measured. Moreover, whether Tanshinone IIA has direct effects on neutrophil migration and activation was determined in vitro. Our data showed that Tanshinone IIA significantly ameliorated the severity of DSS-induced colitis in mice, evidenced by the reduced DAI and improved colonic inflammation. In addition, Tanshinone IIA decreased neutrophil infiltration of intestinal mucosa and activation and reduced colonic inflammatory cytokines in DSS-treated mice. Furthermore, Tanshinone IIA was demonstrated to significantly suppress neutrophil migration and activation. These results provide compelling evidence that Tanshinone IIA has a therapeutic potential for alleviating inflammatory colitis in mice, which is possibly mediated by the immunomodulation of neutrophils.

  10. Dextran Microsphere Hepatic Artery Embolization for Hepatoma: Pathological Assessment of Its Efficacy in Resected Cases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To evaluate the therapeutic effect and the mechanism of dextran microsphere hepatic artery embolization for hepatoma. Methods Partial hepatectomy was performed in 11 patients with hepatoma pretreated with dextran microsphere hepatic artery embolization. All specimens were for histopathologic studies in order to observe the destiny of dextran microspheres and necrotic degree of the tumor. Results complete necrosis of the tumor was found in seven cases and incomplete necrosis of the tumor in the rest 4. Tumors in the later were near to areas rich in arterial collateral anastomoses. The extent of tumor necrosis was unrelated to the presence and thickness of tumor capsule and capsular invasions. Dextran microspheres could cause permanent embolization of distal arterioles. The microspheres were very biocompatible and cause little foreign body reaction. No inflammatory changes were seen both inside and outside of the embolized artery 191 days after embolization. Dextran microspheres were not absorbed and the vessel recanalization was also not seen. Dextran microsphere was not found in portal veins. Conclusion Some hepatomas distant from the collateral circulation of arteries could be cured with dextran microsphere hepatic artery embolization alone.

  11. Functional food applications of dextran from Weissella cibaria RBA12 from pummelo (Citrus maxima).

    Science.gov (United States)

    Baruah, Rwivoo; Maina, Ndegwa H; Katina, Kati; Juvonen, Riikka; Goyal, Arun

    2017-02-02

    Weissella cibaria RBA12 isolated from pummelo from Northeast India produces a dextran composed of 97% α-(1→6) linkages in the main chain and 3% α-(1→3) branched linkages. The in vitro prebiotic activity of dextran-RBA12 was explored. Dextran-RBA12 displayed enhanced growth of probiotic Bifidobacterium and Lactobacillus spp., and controlled growth of non-probiotic enteric bacteria. Dextran-RBA12 showed superior resistance to physiological barriers with a maximum hydrolysis of 0.51%, 0.31% and 0.24% by artificial gastric juice, α-amylase and intestinal fluid, respectively, whereas compared to maximum hydrolysis of 25.23%, 19.13% and 6%, respectively after 5h of incubation shown by commercial prebiotic inulin. The production of dextran from Weissella cibaria RBA12 in sourdough prepared from whole wheat flour, wheat bran and rye bran showed the highest dextran of 3.26±0.12% d.w. in rye bran. The overall study summarized that dextran-RBA12 can be used as a prebiotic and also can be easily produced in sourdough. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Effect of Dry Red Grape Pomace as a Nitrite Substitute on the Microbiological and Physicochemical Properties and Residual Nitrite of Dry-cured Sausage

    Directory of Open Access Journals (Sweden)

    Fatemeh Riazi

    2016-07-01

    Full Text Available Background and Objectives: Sodium nitrite and potassium nitrite have been traditionally used for inhibition of Clostridium botulinum and also as an agent to stabilize the color of meat products; however, usage of these additives at high levels could lead to toxicity and cancer originating from the formation of nitrosamines. Nowadays, application of natural preservatives in order to reduce the nitrite content in meat products is increasing. Thus, we used dry red grape pomace (DRGP as a natural alternative to sodium nitrite. Materials and Methods: The effect of two levels of DRGP (1 and 2% on the proximate composition, microbial counts, pH values and residual nitrite level of the samples formulated with two levels of sodium nitrite (30 and 60 mg/kg, as well as the comparison of these sausages with the blank (nitrite-free  and control (full nitrite added samples on the 1rst, 10th, 20th and 30th days of storage at 3-5 °C were evaluated. Results: The results showed that all chemical compositions were in the ranges reported by other researchers, and nitrite was very effective in preventing the microbial growth. Also about 50 % of the ingoing nitrite could be analyzed in the samples after processing. Moreover, the residual nitrite level declined both during the storage of sausage and after the addition of DRGP. Conclusions: The use of DRGP in combination with nitrite for sausages was more effective in keeping the quality and safety of the refrigerated consumer products as indicated by the lower nitrite levels, microbial count and similar composition as compared to the samples treated with nitrite and without nitrite. Keywords: Dry red grape pomace (DRGP, Sausage, Nitrite, Microbial count

  13. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation.

    Science.gov (United States)

    Merino, Leonardo; Darnerud, Per Ola; Toldrá, Fidel; Ilbäck, Nils-Gunnar

    2016-01-01

    The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products.

  14. Nitrite reduction mechanism on a Pd surface.

    Science.gov (United States)

    Shin, Hyeyoung; Jung, Sungyoon; Bae, Sungjun; Lee, Woojin; Kim, Hyungjun

    2014-11-04

    Nitrate (NO3-) is one of the most harmful contaminants in the groundwater, and it causes various health problems. Bimetallic catalysts, usually palladium (Pd) coupled with secondary metallic catalyst, are found to properly treat nitrate-containing wastewaters; however, the selectivity toward N2 production over ammonia (NH3) production still requires further improvement. Because the N2 selectivity is determined at the nitrite (NO2-) reduction step on the Pd surface, which occurs after NO3- is decomposed into NO2- on the secondary metallic catalyst, we here performed density functional theory (DFT) calculations and experiments to investigate the NO2- reduction pathway on the Pd surface activated by hydrogen. Based on extensive DFT calculations on the relative energetics among ∼100 possible intermediates, we found that NO2- is easily reduced to NO* on the Pd surface, followed by either sequential hydrogenation steps to yield NH3 or a decomposition step to N* and O* (an adsorbate on Pd is denoted using an asterisk). Based on the calculated high migration barrier of N*, we further discussed that the direct combination of two N* to yield N2 is kinetically less favorable than the combination of a highly mobile H* with N* to yield NH3. Instead, the reduction of NO2- in the vicinity of the N* can yield N2O* that can be preferentially transformed into N2 via diverse reaction pathways. Our DFT results suggest that enhancing the likelihood of N* encountering NO2- in the solution phase before combination with surface H* is important for maximizing the N2 selectivity. This is further supported by our experiments on NO2- reduction by Pd/TiO2, showing that both a decreased H2 flow rate and an increased NO2- concentration increased the N2 selectivity (78.6-93.6% and 57.8-90.9%, respectively).

  15. Uncertainties in the use of periodate oxidation for determination of dextran structure.

    Science.gov (United States)

    Leonard, G J

    1975-05-01

    A glucan of high molecular weight isolated from stale sugar-cane, and previously shown to have a marked effect on sucrose crystallisation processes-1, is a relatively linear dextran. Approximately 96-97% of its D-glucose residues are involved in (1 yields 6)-alpha-D linkages and constitute the linear backbone of the polymer. The remaining 3-4% of D-glucose residues form branch-points by (1 yields 3)-alpha-D linkages. The periodate-oxidation technique, which has been extensively used by other workers to determine dextran structure, gave erroneous results when applied to the dextran from stale sugar-cane.

  16. Magnetic resonance study of the transmembrane nitrite diffusion.

    Science.gov (United States)

    Samouilov, A; Woldman, Ya Yu; Zweier, J L; Khramtsov, V V

    2007-05-01

    Nitrite (NO(2)-), being a product of metabolism of both nitric oxide (NO(*)) and nitrate (NO(3)-), can accumulate in tissues and regenerate NO() by several mechanisms. The effect of NO(2)- on ischemia/reperfusion injury was also reported. Nevertheless, the mechanisms of intracellular NO(2)- accumulation are poorly understood. We suggested significant role of nitrite penetration through biological membranes in the form of undissociated nitrous acid (HNO(2)). This hypothesis has been tested using large unilamellar phosphatidylcholine liposomes and several spectroscopic techniques. HNO(2) transport across the phospholipid bilayer of liposomes facilitates proton transfer resulting in intraliposomal acidification, which was measured using pH-sensitive probes. NO(2)(-)-mediated intraliposomal acidification was confirmed by EPR spectroscopy using membrane-impermeable pH-sensitive nitroxide, AMC (2,2,5,5-tetramethyl-1-yloxy-2,5-dihydro-1H-imidazol-3-ium-4-yl)-aminomethanesulfonic acid (pK 5.25), and by (31)P NMR spectroscopy using inorganic phosphate (pK 6.9). Nitrite accumulates inside liposomes in concentration exceeding its concentration in the bulk solution, when initial transmembrane pH gradient (alkaline inside) is applied. Intraliposomal accumulation of NO(2)- was observed by direct measurement using chemiluminescence technique. Perfusion of isolated rat hearts with buffer containing 4 microM NO(2)- was performed. The nitrite concentrations in the effluent and in the tissue, measured after 1 min perfusion, were close, supporting fast penetration of the nitrite through the tissue. Measurements of the nitrite/nitrate showed that total concentration of NO(x) in myocardium increased from initial 7.8 to 24.7 microM after nitrite perfusion. Physiological significance of passive transmembrane transport of NO(2)- and its coupling with intraliposomal acidification are discussed.

  17. Increased Salivary Nitrite and Nitrate Excretion in Rats with Cirrhosis.

    Science.gov (United States)

    Mahmoodi, Somayeh; Rahmatollahi, Mahdieh; Shahsavari, Fatemeh; Shafaroodi, Hamed; Grayesh-Nejad, Siyavash; Dehpour, Ahmad R

    2015-11-01

    Increased nitric oxide (NO) formation is mechanistically linked to pathophysiology of the extrahepatic complications of cirrhosis. NO is formed by either enzymatic or non-enzymatic pathways. Enzymatic production is catalyzed by NO synthase (NOS) while entero-salivary circulation of nitrate and nitrite is linked to non-enzymatic formation of NO under acidic pH in the stomach. There is no data on salivary excretion of nitrate and nitrite in cirrhosis. This study was aimed to investigate salivary levels of nitrate and nitrite in a rat model of biliary cirrhosis. Cirrhosis was induced by bile duct ligation (BDL). Four weeks after the operation, submandibular ducts of anesthetized BDL and control rats were cannulated with polyethylene microtube for saliva collection. Assessment of pH, nitrite and nitrate levels was performed in our research. We also investigated NOS expression by real time RT-PCR to estimate eNOS, nNOS and iNOS mRNA levels in the submandibular glands. Salivary pH was significantly lower in BDL rats in comparison to control animals. We also observed a statistically significant increase in salivary levels of nitrite as well as nitrate in BDL rats while there was no elevation in the mRNA expression of nNOS, eNOS, and iNOS in submandibular glands of cirrhotic groups. This indicates that an increased salivary level of nitrite/nitrate is less likely to be linked to increased enzymatic production of NO in the salivary epithelium. It appears that nitrate/nitrite can be transported from the blood stream by submandibular glands and excreted into saliva as entero-salivary circulation, and this mechanism may have been exaggerated during cirrhosis.

  18. In vivo evidence of hepato- and reno-protective effect of garlic oil against sodium nitrite-induced oxidative stress.

    Science.gov (United States)

    Hassan, Hanaa A; El-Agmy, Sherif M; Gaur, Rajiv L; Fernando, Augusta; Raj, Madhwa Hg; Ouhtit, Allal

    2009-01-01

    Sodium nitrite (NaNO2), a food color fixative and preservative, contributes to carcinogenesis. We investigated the protective role of garlic oil against NaNO2-induced abnormalities in metabolic biochemical parameters and oxidative status in male albino rats. NaNO2 treatment for a period of three months induced a significant increase in serum levels of glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, urea and creatinine as well as hepatic AST and ALT. However, significant decrease was recorded in liver ALP activity, glycogen content, and renal urea and creatinine levels. In parallel, a significant increase in lipid peroxidation, and a decrease in glutathione content and catalase activity were observed in the liver and the kidney. However, garlic oil supplementation showed a remarkable amelioration of these abnormalities. Our data indicate that garlic is a phytoantioxidant with powerful chemopreventive properties against chemically-induced oxidative stress.

  19. In vivo evidence of hepato- and reno-protective effect of garlic oil against sodium nitrite-induced oxidative stress

    Directory of Open Access Journals (Sweden)

    Hanaa A Hassan, Sherif M El-Agmy, Rajiv L Gaur, Augusta Fernando, Madhwa HG Raj, Allal Ouhtit

    2009-01-01

    Full Text Available Sodium nitrite (NaNO2, a food color fixative and preservative, contributes to carcinogenesis. We investigated the protective role of garlic oil against NaNO2-induced abnormalities in metabolic biochemical parameters and oxidative status in male albino rats. NaNO2 treatment for a period of three months induced a significant increase in serum levels of glucose, aspartate aminotransferase (AST, alanine aminotransferase (ALT, alkaline phosphatase (ALP, bilirubin, urea and creatinine as well as hepatic AST and ALT. However, significant decrease was recorded in liver ALP activity, glycogen content, and renal urea and creatinine levels. In parallel, a significant increase in lipid peroxidation, and a decrease in glutathione content and catalase activity were observed in the liver and the kidney. However, garlic oil supplementation showed a remarkable amelioration of these abnormalities. Our data indicate that garlic is a phytoantioxidant with powerful chemopreventive properties against chemically-induced oxidative stress.

  20. Anti-inflammatory and anti-oxidant activities of olmesartan medoxomil ameliorate experimental colitis in rats

    Energy Technology Data Exchange (ETDEWEB)

    Nagib, Marwa M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Misr International University, Cairo (Egypt); Tadros, Mariane G., E-mail: mirogeogo@yahoo.com [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt); ELSayed, Moushira I. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Misr International University, Cairo (Egypt); Khalifa, Amani E. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)

    2013-08-15

    Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) driven through altered immune responses with production of proinflammatory cytokines. Many therapies are used, but side effects and loss of response limit long-term effectiveness. New therapeutic strategies are thus needed for patients who don't respond to current treatments. Recently, there is suggested involvement of the proinflammatory hormone angiotensin II in inflammatory bowel disease. The aim of this study was to investigate the possible role of olmesartan medoxomil (OLM-M), an angiotensin II receptor blocker in ameliorating ulcerative colitis. Colitis was induced in male Wistar rats by administration of 5% dextran sodium sulphate (DSS) in drinking water for 5 days. OLM-M (1, 3 and 10 mg/kg) was administered orally during 21 days prior to the induction of colitis, and for 5 days after. Sulfasalazine (500 mg/kg) was used as reference drug. All animals were tested for changes in colon length, disease activity index (DAI) and microscopic damage. Colon tissue concentration/activity of tumor necrosis alpha (TNF-α), myeloperoxidase (MPO), prostaglandin E2 (PGE2), reduced glutathione (GSH) and malondialdehyde (MDA) were assessed. Results showed that the OLM-M dose-dependently ameliorated the colonic histopathological and biochemical injuries, an effect that is comparable or even better than that of the standard sulfasalazine. These results suggest that olmesartan medoxomil may be effective in the treatment of UC through its anti-inflammatory and antioxidant effects. - Highlights: • Olmesartan medoximil reduced dextran sodium sulphate- induced colitis. • Mechanism involved anti-inflammatory and antioxidant effects dose- dependently. • It suppressed malondialdehyde and restored reduced glutathione levels. • It reduced inflammatory markers levels and histological changes.

  1. cis-Urocanic acid attenuates acute dextran sodium sulphate-induced intestinal inflammation.

    Directory of Open Access Journals (Sweden)

    Eric Albert

    Full Text Available On exposure to sunlight, urocanic acid (UCA in the skin is converted from trans to the cis form and distributed systemically where it confers systemic immunosuppression. The aim of this study was to determine if administration of cis-UCA would be effective in attenuating colitis and the possible role of IL-10. Colitis was induced in 129/SvEv mice by administering 5% dextran sodium sulfate (DSS for 7 days in drinking water. During this period mice received daily subcutaneously injections of cis-UCA or vehicle. To examine a role for IL-10, 129/SvEv IL-10(-/- mice were injected for 24 days with cis-UCA or vehicle. Clinical disease was assessed by measurement of body weight, stool consistency, and presence of blood. At sacrifice, colonic tissue was collected for histology and measurement of myeloperoxidase and cytokines. Splenocytes were analyzed for CD4+CD25+FoxP3+ T-regulatory cells via flow cytometry. Murine bone-marrow derived antigen-presenting cells were treated with lipopolysaccharide (LPS ± UCA and cytokine secretion measured. Our results demonstrated that cis-UCA at a dose of 50 µg was effective in ameliorating DSS-induced colitis as evidenced by reduced weight loss and attenuated changes in colon weight/length. This protection was associated with reduced colonic expression of CXCL1, an increased expression of IL-17A and a significant preservation of splenic CD4+CD25+FoxP3+ T-regulatory cells. cis-UCA decreased LPS induced CXCL1, but not TNFα secretion, from antigen-presenting cells in vitro. UCA reduced colonic levels of IFNγ in IL-10(-/- mice but did not attenuate colitis. In conclusion, this study demonstrates that cis-urocanic acid is effective in reducing the severity of colitis in a chemically-induced mouse model, indicating that pathways induced by ultraviolet radiation to the skin can influence distal sites of inflammation. This provides further evidence for a possible role for sunlight exposure in modulating inflammatory

  2. Development of an optical redox chemical sensor for nitrite determination

    Directory of Open Access Journals (Sweden)

    Saadat Rastegarzadeh

    2012-01-01

    Full Text Available An optical chemical sensor for the determination of nitrite based on incorporating methyltrioctylammonium chloride as an anionic exchanger on the triacetylcellulose polymer has been reported. The response of the sensor is based on the redox reaction between nitrite in aqueous solution and iodide adsorbed on sensing membrane using anion exchange phenomena. The sensing membrane reversibly responses to nitrite ion over the range of 6.52×10-6 - 8.70×10-5 mol L-1 with a detection limit of 6.05×10-7 mol L-1 (0.03 µg mL-1 and response time of 6 min. The relative standard deviation for eight replicate measurements of 8.70×10-6 and 4.34×10-5 mol L-1 of nitrite was 4.4 and 2.5 %, respectively. The sensor was successfully applied for determination of nitrite in food, saliva and water samples.

  3. Sodium nitrite: the "cure" for nitric oxide insufficiency.

    Science.gov (United States)

    Parthasarathy, Deepa K; Bryan, Nathan S

    2012-11-01

    This process of "curing" food is a long practice that dates back thousands of years long before refrigeration or food safety regulations. Today food safety and mass manufacturing are dependent upon safe and effective means to cure and preserve foods including meats. Nitrite remains the most effective curing agent to prevent food spoilage and bacterial contamination. Despite decades of rigorous research on its safety and efficacy as a curing agent, it is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite that is currently being developed as novel therapies for conditions associated with nitric oxide (NO) insufficiency. Much of the same biochemistry that has been understood for decades in the meat industry has been rediscovered in human physiology. This review will highlight the fundamental biochemistry of nitrite in human physiology and highlight the risk benefit evaluation surrounding nitrite in food and meat products. Foods or diets enriched with nitrite can have profound positive health benefits.

  4. Phase-transition and aggregation characteristics of a thermoresponsive dextran derivative in aqueous solutions.

    Science.gov (United States)

    Shi, Huan-Ying; Zhang, Li-Ming

    2006-10-16

    Grafting of poly(N-vinylcaprolactam) side chains onto a hydrophilic dextran backbone was found to provide the dextran with new, thermoresponsive properties in aqueous solutions. Depending on its solution concentration, the resulting dextran derivative could exhibit a temperature-induced phase-transition and critical transition temperature (T(c)). Different anions and cations of added salts, including five potassium salts and five alkali-metal chlorides, were observed to influence the T(c) value of its aqueous solution. Except for potassium iodide, all added salts were found to lower the T(c) value. The addition of the surfactant, cationic cetyltrimethylammonium bromide or anionic sodium dodecyl sulfate, resulted in an increase of the T(c) value. With the help of the Coomassie Brilliant Blue dye as a polarity probe, the formation of hydrophobic aggregates above the T(c) was revealed for this new dextran derivative in aqueous solution.

  5. Crystallization and preliminary X-ray analysis of Streptococcus mutans dextran glucosidase

    Energy Technology Data Exchange (ETDEWEB)

    Saburi, Wataru; Hondoh, Hironori, E-mail: hondoh@abs.agr.hokudai.ac.jp [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan); Unno, Hideaki [Faculty of Engineering, Nagasaki University, Bunkyo-machi, Nagasaki 852-8521 (Japan); Okuyama, Masayuki; Mori, Haruhide [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan); Nakada, Toshitaka [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Matsuura, Yoshiki [Institute for Protein Research, Osaka University, Suita, Osaka 565-0871 (Japan); Kimura, Atsuo [Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589 (Japan)

    2007-09-01

    Dextran glucosidase from S. mutans was crystallized using the hanging-drop vapour-diffusion method. The crystals diffracted to 2.2 Å resolution. Dextran glucosidase from Streptococcus mutans is an exo-hydrolase that acts on the nonreducing terminal α-1,6-glucosidic linkage of oligosaccharides and dextran with a high degree of transglucosylation. Based on amino-acid sequence similarity, this enzyme is classified into glycoside hydrolase family 13. Recombinant dextran glucosidase was purified and crystallized by the hanging-drop vapour-diffusion technique using polyethylene glycol 6000 as a precipitant. The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 72.72, b = 86.47, c = 104.30 Å. A native data set was collected to 2.2 Å resolution from a single crystal.

  6. Inhibitory effect of substituted dextrans on MCF7 human breast cancer cell growth in vitro.

    Science.gov (United States)

    Morere, J F; Letourneur, D; Planchon, P; Avramoglou, T; Jozefonvicz, J; Israel, L; Crepin, M

    1992-12-01

    Substituted dextrans can reproduce some of the properties of heparin and can thus be used to alter cellular growth. We studied the effect of heparin (H108), dextran (D), carboxymethylbenzylamide dextran (CMDB) and carboxymethylbenzylamide sulfonate dextran (CMDBS) on the growth of human mammary cells of the MCF7 tumor line. The cells were cultured in minimum Eagle's medium containing 2% fetal calf serum without biopolymer, or with increasing concentrations of H108, D, CMDB or CMDBS. Growth curves were accurately based on cell counting using a Coulter counter. Cell distribution in the various phases of the cycle was analyzed by flow cytometry. Dose-dependent growth inhibitory effects (400-4000 micrograms/ml) were observed. The effect on MCF7 tumor cells was most apparent with CMDBS. The percentage of cells in the S phase decreased with preferential blocking in the G0/G1 phase. Pre-clinical studies can be anticipated as there is an absence of in vivo toxicity.

  7. Probing Conformational Change of Bovine Serum Albumin–Dextran Conjugates under Controlled Dry Heating

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Shuqin; Li, Yunqi; Zhao, Qin; Li, Ji; Xia, Qiuyang; Zhang, Xiaoming; Huang, Qingrong (Rutgers); (Chinese Aca. Sci.); (Jiangnan)

    2015-04-29

    The time-dependent conformational change of bovine serum album (BSA) during Maillard reaction with dextran under controlled dry heating has been studied by small-angle X-ray scattering, fluorescence spectroscopy, dynamic light scattering, and circular dichroism analysis. Through the research on the radii of gyration (Rg), intrinsic fluorescence, and secondary structure, conjugates with dextran coating were found to inhibit BSA aggregation and preserve the secondary structure of native BSA against long-time heat treatment during Maillard reaction. The results suggested that the hydrophilic dextran was conjugated to the compact protein surface and enclosed it and more dextran chains were attached to BSA with the increase of the heating time. The study presented here will be beneficial to the understanding of the conformational evolution of BSA molecules during the dry-heating Maillard reaction and to the control of the protein–polysaccharide conjugate structure.

  8. Dextran and 5-aminosalicylic acid (5-ASA) conjugates: synthesis, characterisation and enzymic hydrolysis.

    Science.gov (United States)

    Ahmad, Shavej; Tester, Richard F; Corbett, Alistair; Karkalas, John

    2006-11-27

    Mesalamine (5-aminosalicylic acid) is the drug of choice for the treatment of Crohn's disease. A scheme for the synthesis of 5-aminosalicylic acid (5-ASA) conjugates of dextrans was developed with a focus on Crohn's disease applications. Dextrans were oxidised using sodium periodate (NaIO(4)), where the aldehyde groups formed were coupled with the alpha-amino (-NH(2)) group of 5-ASA. The resulting imine bonds were unstable in water and were consequently reduced to secondary amine groups. The effects of different aspects of the conjugation reaction were studied. These included the following: the molecular weight of the dextrans, the molar proportion of NaIO(4) to the dextrans (for periodate oxidation), the pH of the conjugation solutions, the ratio 5-ASA to oxidised polysaccharide and the relationship between the degree of conjugation and the amount of enzyme hydrolysis. Conjugates incubated in HCl were stable in 0.5 and 1.0M HCl, but they underwent degradation in 2.0 and 4.0M HCl. Dextrans (MW 20,000) with various degrees of oxidation (12%, 26%, 46%, 65%, 90% and 93%) were also prepared. Each oxidised dextran sample was conjugated with 5-ASA, and the product was quantified by high-performance liquid chromatography (HPLC). Dextrans with a maximum degree of oxidation (93%) unsurprisingly gave maximum conjugation of 5-ASA (49.1mg per 100mg of product) but were resistant to dextranase hydrolysis. Less oxidised dextrans (12%) conjugated proportionally less 5-ASA (15.1mg per 100mg of product) but were successfully hydrolysed by dextranase, suggesting their potential applications for the treatment of Crohn's disease in the distal ileum and proximal colon.

  9. Hydrogen sulfide poisoning: an antidotal role for sodium nitrite?

    Science.gov (United States)

    Hall, A H; Rumack, B H

    1997-06-01

    In 2 separate incidents, 6 patients were poisoned with hydrogen sulfide (H2S) in sewer gas. In the first incident, mixing acid- and sodium hydroxide-based drain cleaners in a confined space resulted in 4 poisonings and 2 deaths. Three would-be rescuers were seriously poisoned and 1 died. Two survivors had neurological sequelae. Sodium nitrite appeared to have some clinical efficacy in 1 case. The second incident involved 2 patients working on a pump in a sewage pond. A patient lying on a raft close to the pond surface was seriously poisoned; sodium nitrite was clinically efficacious and this patient survived without developing neurological sequelae. Sodium nitrite deserves further clinical study as a potential H2S antidote.

  10. Immobilization of nitrite oxidizing bacteria using biopolymeric chitosan media

    Institute of Scientific and Technical Information of China (English)

    Pranee Lertsutthiwong; Duangcheewan Boonpuak; Wiboonluk Pungrasmi; Sorawit Powtongsook

    2013-01-01

    The effects of chitosan characteristics including the degree of deacetylation,molecular weight,particle size,pH pretreatment and immobilization time on the immobilization of nitrite-oxidizing bacteria (NOB) on biopolymeric chitosan were investigated.Nitrite removal efficiency of immobilized NOB depended on the degree of deacetylation,particle size,pH pretreatment on the surface of chitosan and immobilization time.Scanning electron microscope characterization illustrated that the number of NOB cells attached to the surface of chitosan increased with an increment of immobilization time.The optimal condition for NOB immobilization on chitosan was achieved during a 24-hr immobilization period using chitosan with the degree of deacetylation larger than 80% and various particle size ranges between 1-5 mm at pH 6.5.In general,the NOB immobilized on chitosan flakes has a high potential to remove excess nitrite from wastewater and aquaculture systems.

  11. Diaphragmatic, thoracic and limb motor effects of amyl nitrite inhalation.

    Science.gov (United States)

    Macefield, G; Nail, B S

    1985-11-01

    In the pentobarbitone/urethane anaesthetized rabbit and pentobarbitone anaesthetized cat intratracheal inhalation of amyl nitrite, a non-specific smooth muscle relaxant, caused a vagally dependent depression of patellar reflex and spontaneous (thermal shivering and external intercostal inspiratory) motor activities. A prolonged vagally-independent potentiation succeeded the initial inhibition. The potentiation of intercostal activity may account for the increase in tidal volume produced by amyl nitrite after vagotomy. The patellar reflex potentiation survived thoracolumbar spinal transection but could not be attributed to a direct facilitation of neuromuscular or muscular events. A correlation existed between the relative dependence of fusimotor support of a muscle and its susceptibility to the inhibitory and subsequent facilitatory affects of amyl nitrite inhalation. The diaphragm and interchondral muscles, essentially independent of the autogenetic facilitation provided by muscle spindles, demonstrated neither of these effects. Conversely, the intercostal muscles depend greatly on such facilitation, as do the pectoral and limb muscles during thermal shivering.

  12. Cell-repellant dextran coatings of porous titania using mussel adhesion chemistry.

    Science.gov (United States)

    Park, Jae Yoon; Yeom, Jihyeon; Kim, Jee Seon; Lee, Mihyun; Lee, Haeshin; Nam, Yoon Sung

    2013-11-01

    The resistance of bioceramics against non-specific adsorption of serum proteins is critical for a wide range of biomedical applications. Some polysaccharides serve as natural protein-resistant molecules in extracellular matrices; however, the stable adhesion of polysaccharides to ceramic biomaterials in an aqueous solution is very challenging because chemical linkages at organic/inorganic interfaces are susceptible to hydrolytic degradation. Here, a catechol-grafted dextran, which strongly binds to titania (TiO2 ) in an aqueous milieu to effectively suppress cell adhesion through anti-fouling activity against non-specific protein adsorption, is introduced. Catechol is conjugated approximately to 6.7 mol% of glucose units of dextran via a carbamate ester linkage, corresponding to roughly three catechols per dextran chain having an average molecular weight of 6 kDa. Multivalent interactions of catechols with a titanium atom, enabled by the graft-type structure, provide a very stable coating of dextran on this inorganic surface. The adhesion of HeLa cells on the dextran-coated titania surface is reduced by 2.4-fold compared to that on a pristine titania surface. These results suggest that the graft-type incorporation of a small number of catechol moieties along a dextran backbone is an effective means of producing a stable anti-fouling interface on inorganic biomaterials in an aqueous environment.

  13. An efficient acetylation of dextran using in situ activated acetic anhydride with iodine

    Directory of Open Access Journals (Sweden)

    MUHAMMAD A. HUSSAIN

    2010-02-01

    Full Text Available A facile, efficient, cost-effective and solvent-free acetylation method has been developed for the acetylation of dextran. Dextran acetates were successfully synthesized using different molar ratios of acetic anhydride in the presence of iodine as a catalyst without the use of any solvent. The reactions were realized at 50 °C for 3 h under stirring and nitrogen. This efficient method yielded highly pure and organosoluble dextran esters. The reaction appears highly effective for obtaining higher degrees of substitution (DS with great efficiency. Under solvent-free conditions, dextran triacetates were efficiently synthesized. It was also observed that the molar ratio can easily control the DS of pendant groups onto the polymer backbone. Hence, a range of products with varying DS were successfully designed, purified and characterized. Covalent attachment of the pendant groups onto the polymer backbone was verified by spectroscopic techniques. Thermogravimetric analysis indicated that the obtained dextran esters were thermally as stable as dextran. The DS of the pendant groups onto the polymer backbone was calculated using standard acid base titration after saponification. Furthermore, all products were thoroughly characterized by thermal analysis (TG and DTG, and FTIR and 1H-NMR spectroscopic analysis.

  14. Water Kefir grain as a source of potent dextran producing lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Davidović Slađana Z.

    2015-01-01

    Full Text Available Water kefir is abeverage fermented by a microbial consortium captured in kefir grains. The kefir grains matrix is composed of polysaccharide, primarily dextran, whichis produced by members of the microbial consortium. In this study, we have isolated lactic acid bacteria (LAB from non-commercial water kefir grains (from Belgrade, Serbia and screened for dextran production. Among twelve Lisolates threeproduced slime colonies on modified MRS (mMRS agar containing sucrose instead of glucoseand were presumed to produce dextran. Three LABwere identified based on morphological, physiological and biochemical characteristics and 16S rRNA sequencing as Leuconostoc mesenteroides(strains T1 and T3 and Lactobacillus hilgardii (strain T5. The isolated strains were able to synthesize a substantial amount of dextran in mMRS broth containing 5% sucrose. Maximal yields (11.56, 18.00 and 18.46 g/l were obtained after 16h, 20h and 32h for T1, T3 and T5, respectively. Optimal temperature for dextran production was 23oC for two Leuconostoc mesenteroides strains and 30oC for Lactobacillus hilgardii strain. The produced dextrans were identified based on paper chromatography while the main structure characteristics of purified dextranwere observed by FT-IR spectroscopy. Our study shows that water kefir grains are a natural source of potent dextranproducing LAB. [Projekat Ministarstva nauke Republike Srbije, br. TR 31035

  15. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    Science.gov (United States)

    Siposova, Katarina; Pospiskova, Kristyna; Bednarikova, Zuzana; Safarik, Ivo; Safarikova, Mirka; Kubovcikova, Martina; Kopcansky, Peter; Gazova, Zuzana

    2017-04-01

    Protein transformation from its soluble state into amyloid aggregates is associated with amyloid-related diseases. Amyloid deposits of insulin fibrils have been found in the sites of subcutaneous insulin application in patients with prolonged diabetes. Using atomic force microscopy and ThT fluorescence assay we have investigated the interference of insulin amyloid aggregation with superparamagnetic Fe3O4-based nanoparticles (SPIONs) coated with dextran (DEX); molecular mass of dextran was equal to 15-20, 40 or 70 kDa. The obtained data indicate that all three types of dextran coated nanoparticles (NP-FeDEXs) are able to inhibit insulin fibrillization and to destroy amyloid fibrils. The extent of anti-amyloid activities depends on the properties of NP-FeDEXs, mainly on the size of nanoparticles which is determined by molecular mass of dextran molecules. The most effective inhibiting activity was observed for the smallest nanoparticles coated with 15-20 kDa dextran. Contrary, the highest destroying activity was observed for the largest NP-FeDEX (70 kDa dextran).

  16. Dietary nitrite improves insulin signaling through GLUT4 translocation.

    Science.gov (United States)

    Jiang, Hong; Torregrossa, Ashley C; Potts, Amy; Pierini, Dan; Aranke, Mayank; Garg, Harsha K; Bryan, Nathan S

    2014-02-01

    Diabetes mellitus type 2 is a syndrome of disordered metabolism with inappropriate hyperglycemia owing to a reduction in the biological effectiveness of insulin. Type 2 diabetes is associated with an impaired nitric oxide (NO) pathway that probably serves as the key link between metabolic disorders and cardiovascular disease. Insulin-mediated translocation of GLUT4 involves the PI3K/Akt kinase signal cascade that results in activation of endothelial NO synthase (eNOS). eNOS is dysfunctional during diabetes. We hypothesize that loss of eNOS-derived NO terminates the signaling cascade and therefore cannot activate GLUT4 translocation and that dietary nitrite may repair this pathway. In this study, we administered 50mg/L sodium nitrite to db/db diabetic mice for 4 weeks. After 4 weeks treatment, the db/db mice experienced less weight gain, improved fasting glucose levels, and reduced insulin levels. Cell culture experiments using CHO-HIRc-myc-GLUT4eGFP cell lines stably expressing insulin receptor and myc-GLUT4eGFP protein, as well as L6 skeletal muscle cells stably expressing rat GLUT4 with a Myc epitope (L6-GLUT4myc), showed that NO, nitrite, and GSNO stimulate GLUT4 translocation independent of insulin, which is inhibited by NEM. Collectively our data suggest that nitrite improves insulin signaling through restoration of NO-dependent nitrosation of GLUT4 signaling translocation. These data suggest that NO-mediated nitrosation of GLUT4 by nitrite or other nitrosating agents is necessary and sufficient for GLUT4 translocation in target tissue. Description of this pathway may justify a high-nitrate/nitrite diet along with the glycemic index to provide a safe and nutritional regimen for the management and treatment of diabetes.

  17. Nebulization of the acidified sodium nitrite formulation attenuates acute hypoxic pulmonary vasoconstriction

    Directory of Open Access Journals (Sweden)

    Surber Mark W

    2010-06-01

    Full Text Available Abstract Background Generalized hypoxic pulmonary vasoconstriction (HPV occurring during exposure to hypoxia is a detrimental process resulting in an increase in lung vascular resistance. Nebulization of sodium nitrite has been shown to inhibit HPV. The aim of this project was to investigate and compare the effects of nebulization of nitrite and different formulations of acidified sodium nitrite on acute HPV. Methods Ex vivo isolated rabbit lungs perfused with erythrocytes in Krebs-Henseleit buffer (adjusted to 10% hematocrit and in vivo anesthetized catheterized rabbits were challenged with periods of hypoxic ventilation alternating with periods of normoxic ventilation. After baseline hypoxic challenges, vehicle, sodium nitrite or acidified sodium nitrite was delivered via nebulization. In the ex vivo model, pulmonary arterial pressure and nitric oxide concentrations in exhaled gas were monitored. Nitrite and nitrite/nitrate were measured in samples of perfusion buffer. Pulmonary arterial pressure, systemic arterial pressure, cardiac output and blood gases were monitored in the in vivo model. Results In the ex vivo model, nitrite nebulization attenuated HPV and increased nitric oxide concentrations in exhaled gas and nitrite concentrations in the perfusate. The acidified forms of sodium nitrite induced higher levels of nitric oxide in exhaled gas and had longer vasodilating effects compared to nitrite alone. All nitrite formulations increased concentrations of circulating nitrite to the same degree. In the in vivo model, inhaled nitrite inhibited HPV, while pulmonary arterial pressure, cardiac output and blood gases were not affected. All nitrite formulations had similar potency to inhibit HPV. The tested concentration of appeared tolerable. Conclusion Nitrite alone and in acidified forms effectively and similarly attenuates HPV. However, acidified nitrite formulations induce a more pronounced increase in nitric oxide exhalation.

  18. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    Science.gov (United States)

    Neubauer, H; Götz, F

    1996-04-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conservation, whereas nitrite reductase seems to be a cytosolic enzyme involved in NADH reoxidation. Syntheses of both enzymes are inhibited by oxygen and induced to greater or lesser degrees by nitrate or nitrite, respectively. In whole cells, nitrite reduction is inhibited by nitrate and also by high concentrations of nitrite (> or = 10 mM). Nitrite did not influence nitrate reduction. Two possible mechanisms for the inhibition of nitrite reduction by nitrate that are not mutually exclusive are discussed. (i) Competition for NADH nitrate reductase is expected to oxidize the bulk of the NADH because of its higher specific activity. (ii) The high rate of nitrate reduction could lead to an internal accumulation of nitrite, possibly the result of a less efficient nitrite reduction or export. So far, we have no evidence for the presence of other dissimilatory or assimilatory nitrate or nitrite reductases in S. carnosus.

  19. Bioreducible carboxymethyl dextran nanoparticles for tumor-targeted drug delivery.

    Science.gov (United States)

    Thambi, Thavasyappan; You, Dong Gil; Han, Hwa Seung; Deepagan, V G; Jeon, Sang Min; Suh, Yung Doug; Choi, Ki Young; Kim, Kwangmeyung; Kwon, Ick Chan; Yi, Gi-Ra; Lee, Jun Young; Lee, Doo Sung; Park, Jae Hyung

    2014-11-01

    Bioreducible carboxymethyl dextran (CMD) derivatives are synthesized by the chemical modification of CMD with lithocholic acid (LCA) through a disulfide linkage. The hydrophobic nature of LCA allows the conjugates (CMD-SS-LCAs) to form self-assembled nanoparticles in aqueous conditions. Depending on the degree of LCA substitution, the particle diameters range from 163 to 242 nm. Doxorubicin (DOX), chosen as a model anticancer drug, is effectively encapsulated into the nanoparticles with high loading efficiency (>70%). In vitro optical imaging tests reveal that the fluorescence signal of DOX quenched in the bioreducible nanoparticles is highly recovered in the presence of glutathione (GSH), a tripeptide capable of reducing disulfide bonds in the intracellular compartments. Bioreducible nanoparticles rapidly release DOX when they are incubated with 10 mm GSH, whereas the drug release is greatly retarded in physiological buffer (pH 7.4). DOX-loaded bioreducible nanoparticles exhibit higher toxicity to SCC7 cancer cells than DOX-loaded nanoparticles without the disulfide bond. Confocal laser scanning microscopy observation demonstrate that bioreducible nanoparticles can effectively deliver DOX into the nuclei of SCC7 cells. In vivo biodistribution study indicates that Cy5.5-labeled CMD-SS-LCAs selectively accumulate at tumor sites after systemic administration into tumor-bearing mice. Notably, DOX-loaded bioreducible nanoparticles exhibit higher antitumor efficacy than reduction-insensitive control nanoparticles. Overall, it is evident that bioreducible CMD-SS-LCA nanoparticles are useful as a drug carrier for cancer therapy.

  20. Covalent immobilization of Enterococcus faecalis Esawy dextransucrase and dextran synthesis.

    Science.gov (United States)

    Hashem, Amal M; Gamal, Amira A; Hassan, Mohamed E; Hassanein, Naziha M; Esawy, Mona A

    2016-01-01

    Enterococcus faecalis Esawy dextransucrase was immobilized in Fe(3+)-cross-linked alginate/carboxymethyl cellulose (AC) beads. The gel beads were modified with polyethylenimine (PEI) followed by glutaraldehyde (GA) to form Fe(3+) (ACPG) beads. Fe(3+) (ACPG) was characterized using FTIR and DSC techniques. GA activated beads showed new two peaks. The first was at 1,717 cm(-1) which refers to (CO) group of a free aldehyde end of glutaraldehyde, and another peak was at 1,660 cm(-1) referring to (CN) group. The immobilization process improved the optimum temperature from 35 to 45°C. The immobilized enzyme showed its optimum activity in wide pH range (4.5-5.4) compared to pH 5.4 in case of free form. Also, the immobilization process improved the thermal and pH enzyme stability to great extent. Reusability test proved that the enzyme activity retained 60% after 15 batch reactions. Immobilized enzyme was applied successfully in the synthesis of oligosaccharides and different molecular weights of dextran.

  1. Biotinylated dextran amine anterograde tracing of the canine corticospinal tract

    Institute of Scientific and Technical Information of China (English)

    Xiao Han; Guangming Lv; Huiqun Wu; Dafeng Ji; Zhou Sun; Yaofu Li; Lemin Tang

    2012-01-01

    In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.

  2. Agaricus bisporus attenuates dextran sulfate sodium-induced colitis.

    Science.gov (United States)

    Um, Min Young; Park, Jae Ho; Gwon, So Young; Ahn, Jiyun; Jung, Chang Hwa; Ha, Tae Youl

    2014-12-01

    Agaricus bisporus (white button mushroom, WBM) is widely consumed in most countries and is reported to have anti-inflammatory and antioxidant activities. However, little is known regarding its effects in dextran sulfate sodium (DSS)-induced colitis, which are related to dysfunction of intestinal immunity. The aim of the present study was to investigate the effects of WBMs in an animal model of DSS-induced colitis. Male, 4-week-old ICR mice (n=10 per group) were fed a normal diet with or without 10% WBM for 4 weeks, and colitis was induced by 3% DSS in drinking water for 7 days. WBMs prevented DSS-induced shortening of colon length (P=.033) and diminished diarrhea (P=.049) and gross bleeding (P=.001), resulting in a decreased disease activity index. Results of histological analysis showed that WBMs suppressed mucosal damage. In addition, WBMs attenuated the DSS-induced increase in myeloperoxidase activity (P=.012) and upregulation of proinflammatory cytokine tumor necrosis factor-α (P=.020) in the colon segment. Taken together, these findings suggest a possible role for the WBM as an immunomodulator that can prevent and/or treat ulcerative colitis.

  3. [Protonation of nitrite is an obligatory stage in the generation of nitric oxide from nitrite in biological systems].

    Science.gov (United States)

    Mikoian, V D; Kubrina, L N; Khachatrian, G N; Vanin, A F

    2006-01-01

    The yield of nitric oxide from 1 mM sodium nitrite differs 200 times when the process was initiated by 10 mM sodium dithionite in the solution of 5 or 150 mM HEPES-buffer (pH 7.4). Dithionite acted both as a strong reductant and an agent that induced a local acidification of solutions without notable change in pH value. The amount of nitric oxide was estimated by the EPR method by measuring the incorporation of nitric oxide to water-soluble complexes of Fe with N-methyl-D-glucamine dithiocarbamate (MGD), which led to the formation of EPR-detectable mononitrosyl iron complexes with MGD (MNIC-MGD). Ten seconds after dithionite addition, the concentration of MNIC - MGD complexes reached 2 microM in 5 mM HEPES-buffer in contrast to 0.01 microM in 150 mM HEPES-buffer. The difference was suggested to be due to a higher life-time of zones with decreased pH values in a weaker weak buffer solution. The life-time was high enough to ensure the protonation of a part of nitrite. The resulting nitrous acid was decomposed to form nitric oxide. The difference in the formation of nitric oxide from nitrite was also observed in weak and strong buffer solutions in the presence of hemoglobin (0.3 mM) or serum albumin (0.5 mM). However, the ratios of nitric oxide yields in weak and strong buffer did not exceed 3-4 times. The increase in the formation of nitric oxide from nitrite was characteristic for the solutions containing both proteins. Large amounts of nitric oxide formed from nitrite was observed in mouse liver preparation subjected to freezing-thawing procedure followed by incubation in 150 mM HEPES-buffer (pH 7.4) and addition of dithionite. The proposition was made that the presence of zones with low pH value in cells and tissues can ensure the predominant operation of the acid mechanism formation of nitric oxide from nitrite. The contribution of the formation of nitric oxide from nitrite catalyzing with heme-containing proteins nitrite reductases can be minor one under these

  4. Effect of the kinetics of ammonium and nitrite oxidation on nitritation success or failure for different biofilm reactor geometries

    DEFF Research Database (Denmark)

    Lackner, Susanne; Smets, Barth F.

    2012-01-01

    The effect of biokinetics on nitritation was investigated in two biofilm geometries, the Membrane Aerated Biofilm Reactor (MABR) and a conventional biofilm system. A 1D biofilm model was used and evaluated by global sensitivity analysis using the variance based Sobol method. The main focus...... strongly depends on the chosen kinetic parameters of AOB and NOB. The maximum specific growth rates (μmax,AOB and μmax,NOB) had the strongest impact on nitritation efficiency (NE). In comparison, the counter-diffusion geometry yielded more parameter combinations (27.5%) that resulted in high NE than the co...

  5. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking

    DEFF Research Database (Denmark)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K

    2016-01-01

    , whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry...

  6. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    OpenAIRE

    Neubauer, H.; Götz, F

    1996-01-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conserva...

  7. Color Developing Capacity of Plasma-treated Water as a Source of Nitrite for Meat Curing

    OpenAIRE

    2015-01-01

    The interaction of plasma with liquid generates nitrogen species including nitrite (NO− 2). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate ...

  8. Theoretical study on reaction mechanisms of nitrite reduction by copper nitrite complexes: toward understanding and controlling possible mechanisms of copper nitrite reductase.

    Science.gov (United States)

    Maekawa, Shintaro; Matsui, Toru; Hirao, Kimihiko; Shigeta, Yasuteru

    2015-04-30

    Using density functional theory, we studied denitrification reaction mechanisms of copper adducts of tris(pyrazolyl)methane and hydrotris(pyrazolyl)borate models of a copper nitrite reductase (Cu-NiR), and herein propose several possible reaction pathways, including some parts that have never been examined previously. Because electron and proton transfer reactions participate in the enzymatic cycles of Cu-NiR, the Gibbs energy of a proton in solution, G(H(+)), and the redox potential, Eredox, of the model Cu-NiR are also evaluated. Although the pathway where a nitrite is provided as HNO2 is energetically preferable, a well-known reaction pathway passing through the resting state with an active site occupied by a water molecule where nitrite is provided as NO2(-) is the main recognized pathway under normal conditions. These features do not change whether the electron transfer occurs before production of NO or not. However, our results suggest that the pathway involving HNO2 might become dominant under low pH conditions in conjunction with experimental results.

  9. Dextran: Influence of Molecular Weight in Antioxidant Properties and Immunomodulatory Potential

    Directory of Open Access Journals (Sweden)

    Vinicius C. Soeiro

    2016-08-01

    Full Text Available Dextrans (α-d-glucans extracted from Leuconostoc mesenteroides, with molecular weights (MW of 10 (D10, 40 (D40 and 147 (D147 kDa, were evaluated as antioxidant, anticoagulant and immunomodulatory drugs for the first time. None presented anticoagulant activity. As for the antioxidant and immunomodulatory tests, a specific test showed an increase in the dextran activity that was proportional to the increase in molecular weight. In a different assay, however, activity decreased or showed no correlation to the MW. As an example, the reducing power assay showed that D147 was twice as potent as other dextrans. On the other hand, all three samples showed similar activity (50% when it came to scavenging the OH radical, whereas only the D10 sample showed sharp activity (50% when it came to scavenging the superoxide ion. D40 was the single dextran that presented with immunomodulatory features since it stimulated the proliferation (~50% of murine macrophages (RAW 264.7 and decreased the release of nitric oxide (~40% by the cells, both in the absence and presence of lipopolysaccharides (LPS. In addition, D40 showed a greater scavenging activity (50% for the hydrogen peroxide, which caused it to also be the more potent dextran when it came to inhibiting lipid peroxidation (70%. These points toward dextrans with a 40 kDa weight as being ideal for antioxidant and immunomodulatory use. However, future studies with the D40 and other similarly 40 kDa dextrans are underway to confirm this hypothesis.

  10. Nitrite enhances liver graft protection against cold ischemia ...

    African Journals Online (AJOL)

    Amani Cherif-Sayadi

    2017-03-30

    Mar 30, 2017 ... Introduction: Nitrite has been found to protect liver graft from cold preservation injury. However, ..... Relevance of epidermal growth factor to improve stea- totic liver ... [19] Li H, Sun -J-J, Chen G-Y, et al. Carnosic acid nanoparti ...

  11. Serum nitrite levels in Sri Lankan patients with leptospirosis

    Institute of Scientific and Technical Information of China (English)

    Rohini I Gunaratna; Shiroma M Handunnetti; MRC Bulathsinghalage; Pranitha Somaratne; Ananda Jayanaga; HJ de Silva; Senaka Rajapakse

    2012-01-01

    Objective:To determine whether blood nitrite levels are elevated in patients with leptospirosis. Methods: Male patients fulfilling clinical and epidemiological criteria for a diagnosis of leptospirosis were recruited. Those with MAT titre of≥400 together with those seroconverting to a titer of≥200 were included in the analysis. Serum nitrite levels were measured in these patients and age, sex matched healthy controls. Results:Patients from 3 hospitals (n=75) were screened during a 3 month period from 28th June to 3rd September 2009, of whom 20 were eligible for the study. Serum nitrite levels were found to be significantly higher in patients with acute leptospirosis [n=20, (0.359±0.229)μM] compared to controls [(n=13,(0.216±0.051)μM] (P=0.014). A significant correlation was also observed between the MAT titre and the day of illness (r = 0.547; P<0.0001). Conclusions: Serum nitrite levels are higher in patients with acute leptospirosis compared to age and sex matched controls. No correlation could be assessed with severity of illness, as sample size was inadequate to determine this.

  12. Evaluation of nitrate and nitrite destruction/separation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1997-08-29

    This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

  13. Electrochemical removal of nitrite in simulated aquaculture wastewater

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... African Journal of Biotechnology Vol. 10(73), pp. ... wastewater can also be treated efficiently for the removal of nitrite in both batch and continuous scales ... the aquaculture industry's rapid growth and is now regarded as the ...

  14. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.

    Science.gov (United States)

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-03-09

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.

  15. The intramolecular electron transfer between copper sites of nitrite reductase

    DEFF Research Database (Denmark)

    Farver, O; Eady, R R; Abraham, Z H

    1998-01-01

    The intramolecular electron transfer (ET) between the type 1 Cu(I) and the type 2 Cu(II) sites of Alcaligenes xylosoxidans dissimilatory nitrite reductase (AxNiR) has been studied in order to compare it with the analogous process taking place in ascorbate oxidase (AO). This internal process...

  16. Aedes aegypti salivary gland extract ameliorates experimental inflammatory bowel disease.

    Science.gov (United States)

    Sales-Campos, Helioswilton; de Souza, Patricia Reis; Basso, Paulo José; Ramos, Anderson Daniel; Nardini, Viviani; Chica, Javier Emílio Lazo; Capurro, Margareth Lara; Sá-Nunes, Anderson; de Barros Cardoso, Cristina Ribeiro

    2015-05-01

    Current therapies for inflammatory bowel disease (IBD) are not totally effective, resulting in persistent and recurrent disease for many patients. Mosquito saliva contains immunomodulatory molecules and therein could represent a novel therapy for IBD. Here, we demonstrated the therapeutic activity of salivary gland extract (SGE) of Aedes aegypti on dextran sulfate sodium (DSS)-induced colitis. For this purpose, C57BL/6 male mice were exposed to 3% DSS in drinking water and treated with SGE at early (days 3-5) or late (days 5-8) time points, followed by euthanasia on days 6 and 9, respectively, for sample collection. The results showed an improvement in clinical disease outcome and postmortem scores after SGE treatment, accompanied by the systemic reduction in peripheral blood lymphocytes, with no impact on bone marrow and mesenteric lymph nodes cellularity or macrophages toxicity. Moreover, a local diminishment of IFN-γ, TNF-α, IL-1β and IL-5 cytokines together with a reduction in the inflammatory area were observed in the colon of SGE-treated mice. Strikingly, early treatment with SGE led to mice protection from a late DSS re-challenging, as observed by decreased clinical and postmortem scores, besides reduced circulating lymphocytes, indicating that the mosquito saliva may present components able to prevent disease relapse. Indeed, high performance liquid chromatography (HPLC) experiments pointed to a major SGE pool fraction (F3) able to ameliorate disease signs. In conclusion, SGE and its components might represent a source of important immunomodulatory molecules with promising therapeutic activity for IBD.

  17. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Science.gov (United States)

    2010-04-01

    ... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.177 Sodium nitrite used in processing smoked chub. The food additive sodium nitrite may be safely used in combination with salt (NaCl) to aid in... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite used in processing smoked chub....

  18. Neurotoxicity induced by alkyl nitrites: Impairment in learning/memory and motor coordination.

    Science.gov (United States)

    Cha, Hye Jin; Kim, Yun Ji; Jeon, Seo Young; Kim, Young-Hoon; Shin, Jisoon; Yun, Jaesuk; Han, Kyoungmoon; Park, Hye-Kyung; Kim, Hyung Soo

    2016-04-21

    Although alkyl nitrites are used as recreational drugs, there is only little research data regarding their effects on the central nervous system including their neurotoxicity. This study investigated the neurotoxicity of three representative alkyl nitrites (isobutyl nitrite, isoamyl nitrite, and butyl nitrite), and whether it affected learning/memory function and motor coordination in rodents. Morris water maze test was performed in mice after administrating the mice with varying doses of the substances in two different injection schedules of memory acquisition and memory retention. A rota-rod test was then performed in rats. All tested alkyl nitrites lowered the rodents' capacity for learning and memory, as assessed by both the acquisition and retention tests. The results of the rota-rod test showed that isobutyl nitrite in particular impaired motor coordination in chronically treated rats. The mice chronically injected with isoamyl nitrite also showed impaired function, while butyl nitrite had no significant effect. The results of the water maze test suggest that alkyl nitrites may impair learning and memory. Additionally, isoamyl nitrite affected the rodents' motor coordination ability. Collectively, our findings suggest that alkyl nitrites may induce neurotoxicity, especially on the aspect of learning and memory function.

  19. The redox interplay between nitrite and nitric oxide: From the gut to the brain

    Directory of Open Access Journals (Sweden)

    Cassilda Pereira

    2013-01-01

    We here discuss the implications of the redox conversion of nitrite to ·NO in the gut, how nitrite-derived ·NO may signal from the digestive to the central nervous system, influencing brain function, as well as a putative ascorbate-driven nitrite/NO pathway occurring in the brain.

  20. Growth inhibition of human melanoma tumor cells by the combination of sodium phenylacetate (NaPA) and substituted dextrans and one NaPA-dextran conjugate.

    Science.gov (United States)

    Gervelas, C; Avramoglou, T; Crépin, M; Jozefonvicz, J

    2002-01-01

    We have studied the cytostatic effects of sodium phenylacetate (NaPA) in association with several substituted dextrans on human tumor melanoma 1205LU cells. We show that NaPA alone inhibits the growth of these cells (IC50 = 3.9 mM) while a weak inhibitory effect appears at a concentration of 37 microM (10 microg/ml) for a dextran methyl carboxylate benzylamide (LS17-DMCB). The precursors of LS17-DMCB [T40 Dextran and carboxymethyl dextran (LS17-DMC)] did not affect the growth of 1205LU cells. To potentiate the inhibitory activity of NaPA at low concentrations (below 5.6 mM), we have tested NaPA and LS17-DMCB in physical mixture (association) or linked together covalently (this conjugate is termed 'LS17-NaPaC'). We have observed an increase of the 1205LU cell growth inhibition effect with NaPA in association (IC50 1.8 mM). For a concentration of 5 mM of NaPA (free in the case of association or linked in the case of conjugate), the association with dextran derivative exhibits a 4.6-fold higher efficacy than with NaPA alone (9 versus 41% surviving fraction), while the conjugate is 1.3-fold smaller (52% growth inhibition). By performing isobologram analysis of the IC50 data, we have shown a synergistic effect for a particular molar ratio of NaPA and LS17-DMCB (NaPA:LS17-DMCB = 0.35).

  1. Correlation between UV-VIS spectra and the structure of Cu(II) complexes with hydrogenated dextran in alkaline solutions

    OpenAIRE

    Nikolić Goran S.; Cakić Milorad D.; Mitić Žarko J.; Nikolić Ružica S.; Ilić Ljubomir A.

    2005-01-01

    UV-VIS spectrophotometric investigations of Cu(II) complexes with hydroge-nated dextran showed that the complexation of Cu(II)-ions began at pH > 7. The formation of Cu(II) complexes with dextran monomer units was observed at pH 7-12. With further increase in solution pH > 12, the Cu(II)-dextran complex decomposed to Cu(OH)42~-ions and dextran. With increasing solution pH the absorption maximum of complex solutions increased and shifted to shorter wavelength (hypsochromic shift) compare...

  2. Urinary nitrite excretion after prophylactic intravenous immunoglobulin in premature infants.

    Science.gov (United States)

    Ozkan, H; Uzuner, N; Oren, H; Cabuk, N; Işlekel, H

    2000-02-01

    To investigate the correlation between the prophylactic administration of intravenous immunoglobulin (IVIG) to preterm infants and urinary nitrite levels, which can be utilized as an index of endogenous nitric oxide (NO) formation, and to determine if NO formation plays a role in both therapeutic and adverse effects of IVIG. 28 healthy preterm infants were included in this prospective study. They had a mean gestational age of 29.4 +/- 2.2 weeks and weight of 1,387 +/- 371 g. Prophylactic IVIG infusion at a dose of 0.5 g/kg/day was administered when they were 3-10 days old. Urine samples of the neonates were obtained for analysis on days 1, 2 and 3 after IVIG administration as well as 1 day before. Urinary nitrite levels obtained in the subjects were normalized for urinary creatinine concentrations. The mean urinary nitrite levels were: 2.77 +/- 1.66 micromol/mmol creatinine before IVIG administration; 4.33 +/- 3.88 micromol/mmol creatinine on the 1st day of IVIG; 3.77 +/- 2.73 micromol/mmol creatinine on the 2nd day, and 3.64 +/- 3.28 micromol/mmol creatinine on the 3rd day. There was a significant increase in urinary nitrite levels between before and after IVIG administration. There was no statistical difference in urinary nitrate levels between days 1, 2 and 3 after IVIG administration. We demonstrated that urinary nitrite excretion is significantly elevated in preterm infants after prophylactic IVIG administration and this result suggests that endogenous NO formation may play an important role in both the therapeutic and adverse effects of IVIG. Copyright 2000 S. Karger AG, Basel

  3. Nitrogen removal via nitrite from municipal landfill leachate

    Institute of Scientific and Technical Information of China (English)

    WU Lina; PENG Chengyao; ZHANG Shujun; PENG Yongzhen

    2009-01-01

    A system consisting of a two-stage up-flow anaerobic sludge blanket (UASB),an anoxic/aerobic (A/O) reactor and a sequencing batch reactor (SBR),was used to treat landfill leachate.During operation,denitrification and methanogenesis took place simultaneously in the first stage UASB (UASB1),and the effluent chemical oxygen demand (COD) was further removed in the second stage UASB (UASB2).Then the denitrification of nitrite and nitrate in the returned sludge by using the residual COD was accomplished in the A/O reactor,and ammonia was removed via nitrite in it.Last but not least,the residual ammonia was removed in SBR as well as nitrite and nitrate which were produced by nitrification.A system consisting of a two-stage UASB and an A/O reactor was used to achieve the stable short-cut nitrification in the first stage (60 d).The effluent of stage one was treated by SBR in the second stage (60 d).The results over 120 d were as follows: when the total nitrogen (TN) concentration of influent leachate was about 2500 mg/L and the ammonia nitrogen concentration was about 2000 mg/L,the short-cut nitrification with 85%-90% nitrite accumulation was achieved stably in the A/O reactor.The TN and ammonia nitrogen removal efficiencies of the system were 98% and 97%,respectively.The residual ammonia,nitrite and nitrate which were produced by nitrification in the A/O reactor could be washed out almost completely in SBR.The TN and ammonia nitrogen concentrations of final effluent were about 39 mg/L and 12 mg/L,respectively.

  4. Effects of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as end product

    Institute of Scientific and Technical Information of China (English)

    YU De-shuang; PENG Yong-zhen; ZHANG Kui

    2004-01-01

    The effect of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as the end productwas studied by using a SBR. Experimental results indicated that the growth of nitrobacteria was inhibited and veryhigh levels of nitrite accumulation at different salinities were achieved under the conditions of 25-28 ℃, pH 7.5-8.0, and the influent ammonia nitrogen of 40-70 mg/L when seawater flow used to flush toilet was less than 35%(salinity 12393 mg/L, Cl- 6778 mg/L) of total domestic wastewater flow, which is mainly ascribed to much highchlorine concentration of seawater. Results showed that high seawater salinity is available for short-range nitrificationto nitrite as the end product. When the seawater flow used to flush toilet accounting for above 70% of the totaldomestic wastewater flow, the removal efficiency of ammonia was still above 80% despite the removal of organicsdeclined obviously(less than 60% ). It was found that the effect of seawater salinity on the removal of organics wasnegative rather than positive one as shown for ammonia removal.

  5. Achieving nitrogen removal via nitrite in a pilot-scale continuous pre-denitrification plant.

    Science.gov (United States)

    Ma, Yong; Peng, Yongzhen; Wang, Shuying; Yuan, Zhiguo; Wang, Xiaolian

    2009-02-01

    Nitrogen removal via nitrite (the nitrite pathway) is beneficial for carbon-limited biological wastewater treatment plants. However, partial nitrification to nitrite has proven difficult in continuous processes treating domestic wastewater. The nitrite pathway is achieved in this study in a pilot-scale continuous pre-denitrification plant (V=300 L) treating domestic wastewater by controlling the dissolved oxygen (DO) concentration at 0.4-0.7 mg/L. It is demonstrated that the nitrite pathway could be repeatedly and reliably achieved, with over 95% of the oxidized nitrogen compounds at the end of the aerobic zone being nitrite. The nitrite pathway improved the total nitrogen (TN) removal by about 20% in comparison to the nitrate pathway, and also reduced aeration costs by 24%. FISH analysis showed that the nitrite oxidizing bacteria (NOB) population gradually reduced at low DO levels, and reached negligible levels when stable nitrite pathway was established. It is hypothesized that NOB was washed out due to its relatively lower affinity with oxygen. A lag phase was observed in the establishment of the nitrite pathway. Several sludge ages were required for the onset of the nitrite pathway after the application of low DO levels. However, nitrite accumulation increased rapidly after that. A similar lag phase was observed for the upset of the nitrite pathway when a DO concentration of 2-3 mg/L was applied. The nitrite pathway negatively impacted on the sludge settleability. A strong correlation between the sludge volume index and the degree of nitrite accumulation was observed.

  6. Preparation of hydroxypropyl cyclosophoraose/dextran microspheres for the controlled release of ciprofloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Benel; Jeong, Da Ham; Joo, Sang Woo; Choi, Jae Min; Jung, Seung Ho; Cho, Eun Na [Center for Biotechnology Research in UBITA (CBRU), Konkuk University, Seoul (Korea, Republic of); Lee, Jae Yung [Dept. Biological Science, Mokpo National University, Mokpo (Korea, Republic of); Park, Se Yeon [Dept. Applied Chemistry, Dongduk Women' s University, Seoul (Korea, Republic of)

    2016-12-15

    Hydroxypropyl cyclosophoraose/dextran (HPCys/dextran) microspheres were prepared using an emulsion polymerization method for use as drug carriers to achieve the controlled release of a poorly water-soluble antibacterial drug, ciprofloxacin (CFX). Cyclosophoraoses are cyclic (1 → 2)-β-d-glucans isolated from the Rhizobium species. Characteristics of HPCys/dextran microspheres were investigated using Fourier transform infrared analysis, solid-state 13C nuclear magnetic resonance spectroscopy, and field emission scanning electron microscopy. The amount of CFX released from these microspheres at pH 7.4 (intestinal phase pH) was about two times higher than that released at pH 1.2 (gastric phase pH). Furthermore, HPCys/dextran microspheres did not show any toxicity in human embryonic kidney cells. We propose that HPCys/dextran microspheres could be used as an effective pH-dependent release system for poorly water-soluble drugs such as CFX.

  7. Antiviral activity of derivatized dextrans on HIV-1 infection of primary macrophages and blood lymphocytes.

    Science.gov (United States)

    Seddiki, N; Mbemba, E; Letourneur, D; Ylisastigui, L; Benjouad, A; Saffar, L; Gluckman, J C; Jozefonvicz, J; Gattegno, L

    1997-11-28

    The present study demonstrates at the molecular level that dextran derivatives carboxymethyl dextran benzylamine (CMDB) and carboxymethyl dextran benzylamine sulfonate (CMDBS), characterized by a statistical distribution of anionic carboxylic groups, hydrophobic benzylamide units, and/or sulfonate moieties, interact with HIV-1 LAI gp120 and V3 consensus clades B domain. Only limited interaction was observed with carboxy-methyl dextran (CMD) or dextran (D) under the same conditions. CMDBS and CMDB (1 microM) strongly inhibited HIV-1 infection of primary macrophages and primary CD4+ lymphocytes by macrophage-tropic and T lymphocyte-tropic strains, respectively, while D or CMD had more limited effects on M-tropic infection of primary macrophages and exert no inhibitory effect on M- or T-tropic infection of primary lymphocytes. CMDBS and CMDB (1 microM) had limited but significant effect on oligomerized soluble recombinant gp120 binding to primary macrophages while they clearly inhibit (> 50%) such binding to primary lymphocytes. In conclusion, the inhibitory effect of CMDB and the CMDBS, is observed for HIV M- and T-tropic strain infections of primary lymphocytes and macrophages which indicates that these compounds interfere with steps of HIV replicative cycle which neither depend on the virus nor on the cell.

  8. Induction heating studies of dextran coated MgFe2O4 nanoparticles for magnetic hyperthermia.

    Science.gov (United States)

    Khot, V M; Salunkhe, A B; Thorat, N D; Ningthoujam, R S; Pawar, S H

    2013-01-28

    MgFe(2)O(4) nanoparticles with sizes around 20 nm have been prepared by a combustion method and functionalized with dextran for their possible applications in magnetic particle hyperthermia. The induction heating study of these nanoparticles at different magnetic field amplitudes, from 6.7 kA m(-1) to 26.7 kA m(-1), showed self-heating temperature rise up to 50.25 °C and 73.32 °C (at 5 mg mL(-1) and 10 mg mL(-1) concentrations in water respectively) which was primarily thought to be due to hysteresis losses activated by an AC magnetic field. The dextran coated nanoparticles showed a maximum specific absorption rate (SAR) of about 85.57 W g(-1) at 26.7 kA m(-1) (265 kHz). Dextran coated nanoparticles at concentrations below 1.8 mg mL(-1) exhibit good viability above 86% on mice fibroblast L929 cells. The results suggest that combustion synthesized MgFe(2)O(4) nanoparticles coated with dextran can be used as potential heating agents in magnetic particle hyperthermia. Uncoated and dextran coated samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TG-DTA) and zeta potential-DLS studies.

  9. Effect of dextran 500 on radial migration of erythrocytes in postcapillary venules at low flow rates.

    Science.gov (United States)

    Kim, Sangho; Ong, Peng Kai; Johnson, Paul C

    2009-06-01

    Recently, we reported that collision efficiency (fraction of total collisions that result in the formation of aggregates) between red blood cells was an important factor in the formation of aggregates in postcapillary venules. In the present study, we focus on how high molecular weight dextran influences the overall radial migration trend of red blood cells in the postcapillary venule along a longitudinal distance of 50 microm from the bifurcation which would in turn affect collision behavior of these cells. A radial migration index, which defines the extent of radial migration of individual cells relative to the vessel center, was found to have a larger magnitude after infusion of dextran (1.9 +/- 2.73) compared to that before dextran infusion (1.48 +/- 3.89). This implied that dextran-induced aggregation might provide an external force to actively move cells towards the centerline of the vessel, which could contribute to the greater number of red blood cells participating in collision (16% increase) and aggregate formation. Further analysis of the collision behavior of individual red blood cells revealed that collision frequencies of individual cells decreased from a wide range (1 to 14) to a narrow range (1 to 5) after dextran treatment, indicating the alteration of collision behavior of red blood cells by the presence of aggregates along the flow stream.

  10. Fusion and infection of influenza and Sendai viruses as modulated by dextran sulfate: a comparative study.

    Science.gov (United States)

    Ramalho-Santos, J; de Lima, M C

    2001-06-01

    We have directly compared the effect of two types of dextran sulfate with distinct molecular weights (500 kDa and 5 kDa) on the fusion activity and infectivity of both Sendai and influenza viruses, two lipid-enveloped viruses that differ in their routes of entry into target cells. To correlate membrane merging and infectivity MDCK cells were used as targets for the viruses in both approaches. In either case pronounced inhibition of virus-cell interactions by dextran sulfate was only observed at low pH, even though Sendai virus fuses maximally at pH 7.4. Although membrane merging could not be fully abolished, the inhibitory effect was always greater when the higher molecular weight dextran sulfate was used. The presence of this residual fusion activity, that could not be reduced even with high concentrations of agent, suggests that a limited number of binding sites for dextran sulfate may exist on the viral envelopes. The compounds also inhibited fusion of bound virions, and all results could be reproduced using erythrocyte ghosts as target membranes in the fusion assay, instead of MDCK cells. In agreement with these observations only the infectivity of influenza virus (which requires a low pH-dependent step to enter target cells) was affected by dextran sulfate, again the higher molecular weight compound showing a more pronounced inhibitory effect.

  11. Protective effect of isoquercitrin against acute dextran sulfate sodium-induced rat colitis depends on the severity of tissue damage.

    Science.gov (United States)

    Cibiček, Norbert; Roubalová, Lenka; Vrba, Jiří; Zatloukalová, Martina; Ehrmann, Jiří; Zapletalová, Jana; Večeřa, Rostislav; Křen, Vladimír; Ulrichová, Jitka

    2016-12-01

    Isoquercitrin (quercetin-3-O-β-d-glucopyranoside) is a flavonoid that exhibited antioxidant and anti-inflammatory activities in a number of in vitro and in vivo studies. Experimental evidence from rodent models of inflammatory bowel disease is, however, lacking. This study was designed to examine whether isoquercitrin effectively and dose-dependently attenuates acute dextran sulfate sodium (DSS)-induced rat colitis. Wistar rats were divided into negative control group (exposed to vehicle only), positive control group (DSS-induced colitis plus vehicle), low isoquercitrin group (DSS pretreated with isoquercitrin 1mg/kg/day) and high isoquercitrin group (DSS with isoquercitrin 10mg/kg/day). Isoquercitrin was administered daily for 14days, and during the last 7days rats drank DSS solution. The effect of isoquercitrin on DSS-induced colitis was assessed clinically (e.g. disease activity index), biochemically (tissue myeloperoxidase activity, local cyclooxygenase-2 expression), using histology (standard hematoxylin-eosin-based histomorphometry, immunohistochemical detection of inducible nitric oxide synthase) and hematology (blood count). Isoquercitrin dose-dependently ameliorated whole colon shortening and mitigated DSS-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase in the descending segment of the organ. However, when different parts of colon were assessed histomorphometrically, the results did not globally support the protective role of this flavonoid. Tissue healing trends observable in the descending colon were not apparent in the rectum, where histological damage was most severe. We surmise that isoquercitrin may be effective in the prevention of acute colitis. Besides being dose-dependent, the potency of orally administered isoquercitrin may depend on the severity of tissue damage and/or on the site of its action. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o

  12. Effect of dextran and dextran sulfate on the structural and rheological properties of model acid milk gels.

    Science.gov (United States)

    Pachekrepapol, U; Horne, D S; Lucey, J A

    2015-05-01

    Various types of polysaccharides are widely used in cultured dairy products. However, the interaction mechanisms, between milk proteins and these polysaccharides, are not entirely clear. To explore the interactions between uncharged and charged polysaccharides and the caseins, we used a model acid-milk-gel system, which allowed acidification to occur separately from gelation. The effect of adding uncharged dextran (DX; molecular weight ~2.0×10(6) Da) and negatively charged dextran sulfate (DS; molecular weight ~1.4×10(6) Da) to model acid milk gels was studied. Two concentrations (0.075 and 0.5%, wt/wt) of DX or DS were added to cold milk (~0°C) that had been acidified to pH values 4.4, 4.6, 4.8, or 4.9. Acidified milks containing DX or DS were then quiescently heated at the rate of 0.5°C/min to 30°C, which induced gelation, and gels were then held at 30°C for 17 h to facilitate gel development. Dynamic small-amplitude-oscillation rheology and large-deformation (shear) tests were performed. Microstructure of gels was examined by fluorescence microscopy. Gels made with a high concentration of DX gelled at a lower temperature, but after 17 h at 30°C, these gels exhibited lower storage moduli and lower yield-stress values. At pH 4.8 or 4.9 (pH values greater than the isoelectric point of caseins), addition of 0.5% DS to acidified milk resulted in lower gelation temperature. At pH 4.4 (pH values less than the isoelectric point of caseins), addition of 0.5% DS to acidified milk resulted in gels with very high stiffness values. Gels made at pH 4.8 or 4.9 with both concentrations of DS had much lower stiffness and yield-stress values than control gels. Microstructural analysis indicated that gels made at pH 4.4 with the addition of 0.5% DX exhibited large protein strands and pores, whereas gels made with 0.075% DX or the control gels had a finer protein matrix. At higher pH values (>4.4), gels made with 0.5% DX had a finer structure. At all pH values, gels made

  13. Model-based evaluation on the conversion ratio of ammonium to nitrite in a nitritation process for ammonium-rich wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-ming; YANG Qi; ZENG Guang-ming; A. Cornelius; K. H. Rosenwinkel; S. Kunst; D. Weichgrebe

    2004-01-01

    Modeling for nitritation process was discussed and analyzed quantlitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.

  14. Mangiferin ameliorates the intestinal inflammatory response and the impaired gastrointestinal motility in mouse model of postoperative ileus.

    Science.gov (United States)

    Morais, Talita Cavalcante; Arruda, Bruno Rodrigues; de Sousa Magalhães, Hebert; Trevisan, Maria Teresa Salles; de Araújo Viana, Daniel; Rao, Vietla Satyanarayana; Santos, Flavia Almeida

    2015-05-01

    Our previous study has shown that mangiferin (MGF), a glucosylxanthone from Mangifera indica, exerts gastrointestinal prokinetic action involving a cholinergic mechanism. Postoperative ileus (POI) is a temporary disturbance in gastrointestinal motility following surgery, and intestinal inflammatory response plays a critical role in the pathogenesis of POI. The present study investigated to know whether MGF having anti-inflammatory and prokinetic actions can ameliorate the intestinal inflammation and impaired gastrointestinal transit seen in the mouse model of POI. Experimental POI was induced in adult male Swiss mice by standardized small intestinal manipulation (IM). Twenty-four hours later, gastrointestinal transit was assessed by charcoal transport. MGF was administered orally 1 h before the measurement of GIT. To evaluate the inflammatory response, plasma levels of proinflammatory cytokines TNF-α, IL-1β, IL-6, and chemokine MCP-1, and the myeloperoxidase activity, nitrate/nitrite level, and histological changes of ileum were determined in mice treated or not with MGF. Experimental POI in mice was characterized by decreased gastrointestinal transit and marked intestinal and systemic inflammatory response. MGF treatment led to recovery of the delayed intestinal transit induced by IM. MGF in ileum significantly inhibited the myeloperoxidase activity, a marker of neutrophil infiltration, and nitrate/nitrite level and reduced the plasma levels of TNF-α, IL-1β, IL-6, and MCP-1 as well. MGF treatment ameliorates the intestinal inflammatory response and the impaired gastrointestinal motility in the mouse model of POI.

  15. Renal carbonic anhydrases are involved in the reabsorption of endogenous nitrite.

    Science.gov (United States)

    Chobanyan-Jürgens, Kristine; Schwarz, Alexandra; Böhmer, Anke; Beckmann, Bibiana; Gutzki, Frank-Mathias; Michaelsen, Jan T; Stichtenoth, Dirk O; Tsikas, Dimitrios

    2012-02-15

    Nitrite (ONO(-)) exerts nitric oxide (NO)-related biological actions and its concentration in the circulation may be of particular importance. Nitrite is excreted in the urine. Hence, the kidney may play an important role in nitrite/NO homeostasis in the vasculature. We investigated a possible involvement of renal carbonic anhydrases (CAs) in endogenous nitrite reabsorption in the proximal tubule. The potent CA inhibitor acetazolamide was administered orally to six healthy volunteers (5 mg/kg) and nitrite was measured in spot urine samples before and after administration. Acetazolamide increased abruptly nitrite excretion in the urine, strongly suggesting that renal CAs are involved in nitrite reabsorption in healthy humans. Additional in vitro experiments support our hypothesis that nitrite reacts with CO(2), analogous to the reaction of peroxynitrite (ONOO(-)) with CO(2), to form acid-labile nitrito carbonate [ONOC(O)O(-)]. We assume that this reaction is catalyzed by CAs and that nitrito carbonate represents the nitrite form that is actively transported into the kidney. The significance of nitrite reabsorption in the kidney and the underlying mechanisms, notably a direct involvement of CAs in the reaction between nitrite and CO(2), remain to be elucidated.

  16. Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

    Science.gov (United States)

    Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

    2015-01-01

    The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Experimental study of nitrite accumulation in predenitrification biological nitrogen removal process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effect of dissolved oxygen (DO) concentration on nitrite accumulation was investigated in a pilot-scale pre-denitrification process at room temperature for 100 days.In the first 10 days,due to the instability of the system,the DO concentration fluctuated between 1.0 and 2.0 mg/L.In the next 14 days,the DO concentration was kept at 0.5 mg/L and nitrite accumulation occurred,with the average nitrite accumulation rate at 91%.From the 25th day,the DO concentration was increased to 2.0 mg/L to destroy the nitrite accumulation,but nitrite accumulation rate was still as high as 90%.From the 38th day the nitrite accumulation rate decreased to 15%-30% linearly.From the 50th day,DO concentration was decreased to 0.5 mg/L to resume nitrite accumulation.Until the 83rd day the nitrite accumulation rate began to increase to 80%.Dissolved oxygen was the main cause of nitrite accumulation,taking into account other factors such as pH,free ammonia concentration,temperature,and sludge retention time.Because of the different affinity for oxygen between nitrite oxidizing bacteria and ammonia oxidizing bacteria when DO concentration was kept at 0.5 rag/L,nitrite accumulation occurred.

  18. Coagulation competence for predicting perioperative hemorrhage in patients treated with lactated Ringer's vs. Dextran

    DEFF Research Database (Denmark)

    Rasmussen, Kirsten C; Højskov, Michael; Johansson, Per Ingemar

    2015-01-01

    BACKGROUND: Perioperative hemorrhage may depend on coagulation competence and this study evaluated the influence of coagulation competence on blood loss during cystectomy due to bladder cancer. METHODS: Forty patients undergoing radical cystectomy were included in a randomized controlled trial...... to receive either lactated Ringer's solution or Dextran 70 (Macrodex ®) that affects coagulation competence. RESULTS: By thrombelastography evaluated coagulation competence, Dextran 70 reduced "maximal amplitude" (MA) by 25 % versus a 1 % reduction with the administration of lactated Ringer's solution (P ....001). Blinded evaluation of the blood loss was similar in the two groups of patients - 2339 ml with the use of Dextran 70 and 1822 ml in the lactated Ringer's group (P = 0.27). Yet, the blood loss was related to the reduction in MA (r = -0.427, P = 0.008) and by multiple regression analysis independently...

  19. Morphological alterations of exogenous surfactant inhibited by meconium can be prevented by dextran

    Directory of Open Access Journals (Sweden)

    Stichtenoth Guido

    2006-06-01

    Full Text Available Abstract Background Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM and stereology allows the differentiation of active (large aggregates = LA and inactive (small aggregates = SA subtypes. Methods To determine the in vitro effects of meconium and dextran addition on the morphology of a modified porcine natural surfactant (Curosurf, Curosurf samples were either incubated alone or together with meconium or with meconium and dextran, fixed and processed for TEM. Volume fractions of surfactant subtypes [lamellar body-like forms (LBL, multilamellar vesicles (MV, unilamellar vesicles (UV] were determined stereologically. Results All preparations contained LBL and MV (corresponding to LA as well as UV (corresponding to SA. The volume fraction of UV increased with addition of meconium and decreased with further addition of dextran. Correspondingly, the UV/(LBL+MV ratio (resembling the SA/LA ratio increased when meconium was added and decreased when dextran was added to the surfactant-meconium mixture. Conclusion Meconium causes alterations in the ultrastructural composition of Curosurf that can be visualized and analyzed by TEM and stereology. These alterations resemble an increase in the SA/LA ratio and are paralleled by an increase in minimum surface tension. Dextran prevents these effects and may therefore be a useful additive to exogenous surfactant preparations to preserve their structural and functional integrity, thereby improving their resistance to inactivation.

  20. Synthesis and Characterization of Graft Copolymer of Dextran and 2-Acrylamido-2-methylpropane Sulphonic Acid

    Directory of Open Access Journals (Sweden)

    Venkanna Azmeera

    2012-01-01

    Full Text Available A novel biodegradable graft copolymer of dextran (Dx and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS was synthesized by grafting poly-AMPS chains onto dextran backbone by free radical polymerization using ceric ammonium nitrate (CAN as an initiator. Different amounts of AMPS were used to synthesize four different grades of graft copolymers with different side chain lengths. These grafted polymers were characterized by elemental analysis, FTIR, 1HNMR, rheological technique, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and X-ray diffractometry (XRD. They exhibited efficient flocculation performance in kaolin suspension.

  1. Camomile autofermentation in polyethylene glycol/dextran two-phase system

    Directory of Open Access Journals (Sweden)

    Đaković Sanja D.

    2008-01-01

    Full Text Available The objective of this study was the investigation of the extractive bioconversion of apigenin-7-O-β-glucoside in camomile ligulate flowers into apigenin by autofermentation in polyethylene glycol 6000/dextran 200000 two-phase system. In 22.5% polyethylene glycol/14% dextran aqueous two-phase system the obtained yield of apigenin in the top phase was 96.5%. In the presence of plant material that partiotioned to the interphase, the yield of apigenin in the top phase was 3.5 times higher in comparison to the model system.

  2. Rye bran as fermentation matrix boosts in situ dextran production by Weissella confusa compared to wheat bran.

    Science.gov (United States)

    Kajala, Ilkka; Mäkelä, Jari; Coda, Rossana; Shukla, Shraddha; Shi, Qiao; Maina, Ndegwa Henry; Juvonen, Riikka; Ekholm, Päivi; Goyal, Arun; Tenkanen, Maija; Katina, Kati

    2016-04-01

    The consumption of fiber-rich foods such as cereal bran is highly recommended due to its beneficial health effects. Pre-fermentation of bran with lactic acid bacteria can be used to improve the otherwise impaired flavor and textural qualities of bran-rich products. These positive effects are attributed to enzymatic modification of bran components and the production of functional metabolites like organic acids and exopolysaccharides such as dextrans. The aim of this study was to investigate dextran production in wheat and rye bran by fermentation with two Weissella confusa strains. Bran raw materials were analyzed for their chemical compositions and mineral content. Microbial growth and acidification kinetics were determined from the fermentations. Both strains produced more dextran in rye bran in which the fermentation-induced acidification was slower and the acidification lag phase longer than in wheat bran. Higher dextran production in rye bran is expected to be due to the longer period of optimal pH for dextran synthesis during fermentation. The starch content of wheat bran was higher, which may promote isomaltooligosaccharide formation at the expense of dextran production. W. confusa Cab3 produced slightly higher amounts of dextran than W. confusa VTT E-90392 in all raw materials. Fermentation with W. confusa Cab3 also resulted in lower residual fructose content which has technological relevance. The results indicate that wheat and particularly rye bran are promising matrices for producing technologically significant amounts of dextran, which facilitates the use of nutritionally valuable raw bran in food applications.

  3. Cerebrospinal fluid nitrite/nitrate levels in neurologic diseases.

    Science.gov (United States)

    Milstien, S; Sakai, N; Brew, B J; Krieger, C; Vickers, J H; Saito, K; Heyes, M P

    1994-09-01

    Nitric oxide has been proposed to mediate cytotoxic effects in inflammatory diseases. To investigate the possibility that overproduction of nitric oxide might play a role in the neuropathology of inflammatory and noninflammatory neurological diseases, we compared levels of the markers of nitric oxide, nitrite plus nitrate, in the CSF of controls with those in patients with various neurologic diseases, including Huntington's and Alzheimer's disease, amyotrophic lateral sclerosis, and HIV infection. We found that there were no significant increases in the CSF levels of these nitric oxide metabolites, even in patients infected with HIV or in monkeys infected with poliovirus, both of which have significantly elevated levels of the neurotoxin quinolinic acid and the marker of macrophage activation, neopterin. However, CSF quinolinic acid, neopterin, and nitrite/nitrate levels were significantly increased in a small group of patients with bacterial and viral meningitis.

  4. PENELITIAN TOKSISITAS AKUT NATRIUM NITRIT PADA HEWAN UJI TIKUS

    Directory of Open Access Journals (Sweden)

    Sri Endreswari

    2012-10-01

    Full Text Available The acute toxicity study of sodium nitrite in the period of observation for 14 days has been carried out on adult male and female rats. The substance was administered orally iu the form of solution in distilled water. Each animal was observed carefully for six hours after administration, continued twice daily for 1.4 days, those including general appearance, body weight changes, signs of toxicity mortality and gross pathology finding. The signs of toxicity were tremor, ataxia and convulsion; mortalities were occurred in about two hours after administration. Some animal recovered after two - four hours. The LD50 in male mice was 121 (86,6-169,4 mg/kg b.w., in female was 116 (86-155.4 mg/kg b.w. Based on the LD50 value, sodium nitrite is classified as moderately toxic substances.

  5. Activation of Human Complement System by Dextran-Coated Iron Oxide Nanoparticles Is Not Affected by Dextran/Fe Ratio, Hydroxyl Modifications, and Crosslinking

    DEFF Research Database (Denmark)

    Wang, Guankui; Chen, Fangfang; Banda, Nirmal K

    2016-01-01

    While having tremendous potential as therapeutic and imaging tools, the clinical use of engineered nanoparticles has been associated with serious safety concerns. Activation of the complement cascade and the release of proinflammatory factors C3a and C5a may contribute to infusion-related reactions......, whereas opsonization with C3 fragments promotes rapid recognition and clearance of nanomaterials by mononuclear phagocytes. We used dextran-coated superparamagnetic iron oxide nanoparticles (SPIO), which are potent activators of the complement system, to study the role of nanoparticle surface chemistry...... in inciting complement in human serum. Using complement inhibitors and measuring levels of fluid phase markers (sC5b-9, C5a, and Bb), we found that the majority of human complement activation by SPIO is through the alternative pathways (AP). SPIO prepared with high dextran/iron ratio showed some complement...

  6. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    Science.gov (United States)

    Balk, Melike; Laverman, Anniet M; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  7. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  8. Novel magnetic nanoparticles coated by benzene- and β-cyclodextrin-bearing dextran, and the sorption of polycyclic aromatic hydrocarbon.

    Science.gov (United States)

    Cho, Eunae; Tahir, Muhammad Nazir; Choi, Jae Min; Kim, Hwanhee; Yu, Jae-Hyuk; Jung, Seunho

    2015-11-20

    We present the synthesis of novel magnetic nanoparticles functionalized by benzene- and β-cyclodextrin-derivatized dextran. The grafting strategy was based on the [alkynyl-iron] cluster in the modified dextrans, which were prepared by click reaction from alkyne-modified dextran and benzyl azide or mono-6-O-deoxy-monoazido β-cyclodextrin. Characterization was then carried out by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. Using the developed magnetic nanoparticles, the potential for removing polycyclic aromatic hydrocarbons such as phenanthrene and pyrene by sorption onto the nanomaterials was assessed. In the sorption, pi-stacking interactions of the benzene-derivatized dextran and host-guest chemistry of the β-cyclodextrin-derivatized dextran were considered to be significant. Furthermore, the polysaccharide derivative-coated magnetic adsorbents could be recovered by an external magnet for reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Effects of Liposomal Compositions with Oxidized Dextrans on Functional Activity of U937 Macrophage-Like Cells In Vitro.

    Science.gov (United States)

    Kozhin, P M; Chechushkov, A V; Zaitseva, N S; Lemza, A E; Men'shchikova, E B; Troitskii, A V; Shkurupy, V A

    2015-11-01

    We studied the effects of liposomal pharmaceutical compositions with oxidized dextrans on functional activity of U937 monocyte/macrophage-like cells. Liposomes in the emulsion contained oxidized dextran with a molecular weights of 40 kDa or 70 kDa or isonicotinic acid hydrazide (INAH) conjugated with oxidized dextran (40 kDa). Cell viability was evaluated by MTT test; mitochondrial transmembrane potential and production of superoxide anion and H2O2 were studied by fluorescent methods. The studied compositions exhibited no cytotoxic effect and even improved cell viability and mitochondrial respiration. Liposomes with oxidized 40 kDa dextran, including those with INAH-conjugated dextran, inhibited production of superoxide anion, but increased H2O2 generation.

  10. Simple methods to decrease sodium and nitrite contents in hams

    Directory of Open Access Journals (Sweden)

    Talia Franco-Avila

    2015-07-01

    Full Text Available Introduction: Ham is a product highly consumed by society; however it contains some elements that make it a non-recommended food. Thus, it has been attempted to eliminate or reduce those components.Material and Methods: Content of sodium, nitrites, peroxides and total coliforms were compared after processes of Washing (W and Simple Cooking (SC in turkey and pork ham in a cross-sectional analytical experimental study. Furthermore, sensory acceptance of thesamples through an acceptance test of five points was evaluated. One-way ANOVA with post hoc Bonferroni were used to assess the mean difference between groups. The value of p≤0.05 was considered statistically significant.Results: Both processes reduced the amount of sodium in both types of ham in statistically significant way (p≤0.001. The major percentage of reduction was presented with SC: 73.4% for turkey ham and 63.5% for pork ham. Likewise, the higher percentage of nitrite reduction was 50.6% in pork ham with SC technique (p≤0.05. Peroxide index decreased with both techniques in both hams without statistical significance. Total coliforms count was kept constant in all samples. Higher sensory acceptance of W concerning SC in all sensory characteristics was observed.Conclusions: W and SC techniques reduce sodium, nitrite and peroxide index without affecting the sanitation of hams. Furthermore, W is accepted in all sensory categories. We recommend using W technique before consumption of the product.

  11. Intramolecular electron transfer in Pseudomonas aeruginosa cd(1) nitrite reductase

    DEFF Research Database (Denmark)

    Farver, Ole; Brunori, Maurizio; Cutruzzolà, Francesca

    2009-01-01

    nitrite reductase has been determined in both fully oxidized and reduced states. Intramolecular electron transfer (ET), between c and d(1) hemes is an essential step in the catalytic cycle. In earlier studies of the Pseudomonas stutzeri enzyme, we observed that a marked negative cooperativity......The cd(1) nitrite reductases, which catalyze the reduction of nitrite to nitric oxide, are homodimers of 60 kDa subunits, each containing one heme-c and one heme-d(1). Heme-c is the electron entry site, whereas heme-d(1) constitutes the catalytic center. The 3D structure of Pseudomonas aeruginosa......-controlled bimolecular process, followed by unimolecular electron equilibration between the c and d(1) hemes (k(ET) = 4.3 s(-1) and K = 1.4 at 298 K, pH 7.0). In the case of the mutant, the latter ET rate was faster by almost one order of magnitude. Moreover, the internal ET rate dropped (by approximately 30-fold...

  12. The structure of liquid alkali nitrates and nitrites

    Energy Technology Data Exchange (ETDEWEB)

    Wilding, Martin C.; Wilson, Mark; Ribeiro, Mauro; Benmore, Chris J.; Weber, J K; Alderman, Oliver; Tamalonis, Anthony; Parise, J. B.

    2017-08-28

    High energy X-ray diffraction has been combined with containerless techniques to determine the structure of a series of alkali and ammonium nitrate and nitrite liquids. The systems have been modelled using molecular dynamics simulation which allows for the flexibility of, and movement of charge within, the molecular anions. The model reproduces the experimentally-determined scattering functions in both the low-and high-Q regimes reflecting the inter-and intra-molecular length-scales. For ammonium nitrate the best fit to the diffraction data is obtained by assuming the NH4+ cation to have a radius closer to that for Cs+ rather than a smaller cation such as Rb+ as often previously assumed. The alkali nitrites show an emergent length scale, attributed to the nitrogen-nitrogen spatial correlations, that depends on both temperature and the identity of the alkali cation. The corresponding nitrates show a more subtle effect in the nitrogen-nitrogen correlations. As a result, the nature of this N-N length-scale appears different for the respective nitrites and nitrates.

  13. Black ginseng extract ameliorates hypercholesterolemia in rats

    Directory of Open Access Journals (Sweden)

    Evelyn Saba

    2016-04-01

    Conclusion: Administration of BG extracts to Sprague Dawley rats fed with high-cholesterol diet ameliorated hypercholesterolemia, which was mediated via modulation of cholesterol-metabolizing marker genes. This data throw a light on BG's cardioprotective effects.

  14. Dietary amelioration of Helicobacter infection.

    Science.gov (United States)

    Fahey, Jed W; Stephenson, Katherine K; Wallace, Alison J

    2015-06-01

    We review herein the basis for using dietary components to treat and/or prevent Helicobacter pylori infection, with emphasis on (a) work reported in the last decade, (b) dietary components for which there is mechanism-based plausibility, and (c) components for which clinical results on H pylori amelioration are available. There is evidence that a diet-based treatment may reduce the levels and/or the virulence of H pylori colonization without completely eradicating the organism in treated individuals. This concept was endorsed a decade ago by the participants in a small international consensus conference held in Honolulu, Hawaii, USA, and interest in such a diet-based approach has increased dramatically since then. This approach is attractive in terms of cost, treatment, tolerability, and cultural acceptability. This review, therefore, highlights specific foods, food components, and food products, grouped as follows: bee products (eg, honey and propolis); probiotics; dairy products; vegetables; fruits; oils; essential oils; and herbs, spices, and other plants. A discussion of the small number of clinical studies that are available is supplemented by supportive in vitro and animal studies. This very large body of in vitro and preclinical evidence must now be followed up with rationally designed, unambiguous human trials. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Dietary Amelioration of Helicobacter Infection

    Science.gov (United States)

    Fahey, Jed W.; Stephenson, Katherine K.; Wallace, Alison J.

    2015-01-01

    We review herein the basis for using dietary components to treat and/or prevent Helicobacter pylori infection, with emphasis on: (a) work reported in the last decade, (b) dietary components for which there is mechanism-based plausibility, and (c) components for which clinical results on H. pylori amelioration are available. There is evidence that a diet-based treatment may reduce the levels and/or the virulence of H. pylori colonization without completely eradicating the organism in treated individuals. This concept was endorsed a decade ago by the participants in a small international consensus conference held in Honolulu, Hawaii, USA, and interest in such a diet-based approach has increased dramatically since then. This approach is attractive in terms of cost, treatment, tolerability and cultural acceptability. This review therefore highlights specific foods, food components, and food products, grouped as follows: bee products (e.g. honey and propolis), probiotics, dairy products, vegetables, fruits, oils, essential oils, and herbs, spices and other plants. A discussion of the small number of clinical studies that are available is supplemented by supportive in vitro and animal studies. This very large body of in vitro and pre-clinical evidence must now be followed up with rationally designed, unambiguous human trials. PMID:25799054

  16. The Hepatoprotective Effect of Sodium Nitrite on Cold Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Wei Li

    2012-01-01

    Full Text Available Liver ischemia-reperfusion injury is a major cause of primary graft non-function or initial function failure post-transplantation. In this study, we examined the effects of sodium nitrite supplementation on liver IRI in either Lactated Ringer's (LR solution or University of Wisconsin (UW solution. The syngeneic recipients of liver grafts were also treated with or without nitrite by intra-peritoneal injection. Liver AST and LDH release were significantly reduced in both nitrite-supplemented LR and UW preservation solutions compared to their controls. The protective effect of nitrite was more efficacious with longer cold preservation times. Liver histological examination demonstrated better preserved morphology and architecture with nitrite treatment. Hepatocellular apoptosis was significantly reduced in the nitrite-treated livers compared their controls. Moreover, liver grafts with extended cold preservation time of 12 to 24 hours demonstrated improved liver tissue histology and function post-reperfusion with either the nitrite-supplemented preservation solution or in nitrite-treated recipients. Interestingly, combined treatment of both the liver graft and recipient did not confer protection. Thus, nitrite treatment affords significant protection from cold ischemic and reperfusion injury to donor livers and improves liver graft acute function post-transplantation. The results from this study further support the potential for nitrite therapy to mitigate ischemia-reperfusion injury in solid organ transplantation.

  17. The metabolic impact of extracellular nitrite on aerobic metabolism of Paracoccus denitrificans.

    Science.gov (United States)

    Hartop, K R; Sullivan, M J; Giannopoulos, G; Gates, A J; Bond, P L; Yuan, Z; Clarke, T A; Rowley, G; Richardson, D J

    2017-02-07

    Nitrite, in equilibrium with free nitrous acid (FNA), can inhibit both aerobic and anaerobic growth of microbial communities through bactericidal activities that have considerable potential for control of microbial growth in a range of water systems. There has been much focus on the effect of nitrite/FNA on anaerobic metabolism and so, to enhance understanding of the metabolic impact of nitrite/FNA on aerobic metabolism, a study was undertaken with a model denitrifying bacterium Paracoccus denitrificans PD1222. Extracellular nitrite inhibits aerobic growth of P. denitrificans in a pH-dependent manner that is likely to be a result of both nitrite and free nitrous acid (pKa = 3.25) and subsequent reactive nitrogen oxides generated from the intracellular passage of FNA into P. denitrificans. Increased expression of a gene encoding a flavohemoglobin protein (Fhp) (Pden_1689) was observed in response to extracellular nitrite. Construction and analysis of a deletion mutant established Fhp to be involved in endowing nitrite/FNA resistance at high extracellular nitrite concentrations. Global transcriptional analysis confirmed nitrite-dependent expression of fhp and indicated that P. denitrificans expressed a number of stress response systems associated with protein, DNA and lipid repair. It is therefore suggested that nitrite causes a pH-dependent stress response that is due to the production of associated reactive nitrogen species, such as nitric oxide from the internalisation of FNA.

  18. Efficient fabrication of high-capacity immobilized metal ion affinity chromatographic media: The role of the dextran-grafting process and its manipulation.

    Science.gov (United States)

    Zhao, Lan; Zhang, Jingfei; Huang, Yongdong; Li, Qiang; Zhang, Rongyue; Zhu, Kai; Suo, Jia; Su, Zhiguo; Zhang, Zhigang; Ma, Guanghui

    2016-03-01

    Novel high-capacity Ni(2+) immobilized metal ion affinity chromatographic media were prepared through the dextran-grafting process. Dextran was grafted to an allyl-activated agarose-based matrix followed by functionalization for the immobilized metal ion affinity chromatographic media. With elaborate regulation of the allylation degree, dextran was completely or partly grafted to agarose microspheres, namely, completely dextran-grafted agarose microspheres and partly dextran-grafted ones, respectively. Confocal laser scanning microscope results demonstrated that a good adjustment of dextran-grafting degree was achieved, and dextran was distributed uniformly in whole completely dextran-grafted microspheres, while just distributed around the outside of the partly dextran-grafted ones. Flow hydrodynamic properties were improved greatly after the dextran-grafting process, and the flow velocity increased by about 30% compared with that of a commercial chromatographic medium (Ni Sepharose FF). A significant improvement of protein binding performance was also achieved by the dextran-grafting process, and partly dextran-grafted Ni(2+) chelating medium had a maximum binding capacity for His-tagged lactate dehydrogenase about 2.5 times higher than that of Ni Sepharose FF. The results indicated that this novel chromatographic medium is promising for applications in high-efficiency and large-scale protein purification.

  19. Doenjang prepared with mixed starter cultures attenuates azoxymethane and dextran sulfate sodium-induced colitis-associated colon carcinogenesis in mice

    Directory of Open Access Journals (Sweden)

    Ji-Kang Jeong

    2014-01-01

    Full Text Available Backgrounds: Doenjang is traditional Korean fermented soybean paste and widely known for its various health benefits including anticancer effect. In this study, we manufactured doenjang with the grain-type meju using probiotic mixed starter cultures of Aspegillus oryzae, Bacillus subtilis-SKm, and Lactococcus lactis-GAm to improve the qualities and beneficial properties of doenjang. Materials and Methods: The inhibitory effects of the doenjang prepared with the grain-type meju using mixed starter cultures were investigated in azoxymethane (AOM and dextran sulfate sodium (DSS-induced colon carcinogenesis mice model. AOM and DSS colon carcinogenesis was induced in female C57BL/6 mice, and doenjang was orally administered for 4 weeks. Body weight, colon length, and colon weight of mice were determined, and colonic tissues were histologically evaluated. The serum levels of proinflammatory cytokines as well as the expression of inflammation- and apoptosis-related genes in colonic tissue were also analyzed. Results: Administration of the doenjang using probiotic mixed starter cultures ameliorated the symptoms of colon cancer, and reduced the incidence of neoplasia, and reduced the levels of serum proinflammatory cytokines such as interleukin-6, and tumor necrosis factor-α and inducible nitric oxide synthase and cycloooxygenase-2 expression levels in colonic tissue. In addition, it increased Bax and reduced Bcl-2 expression levels and increased p21 and p53 expression in the colonic tissues. Conclusion: These findings indicate that the doenjang attenuated colon carcinogenesis induced by AOM and DSS by ameliorating the symptoms of colon cancer, reducing the occurrence of neoplasia, regulating proinflammatory cytokine levels, and controlling the expressions of inflammation- and apoptosis-related genes in the colonic tissue.

  20. Intestinal anti-inflammatory activity of apigenin K in two rat colitis models induced by trinitrobenzenesulfonic acid and dextran sulphate sodium.

    Science.gov (United States)

    Mascaraque, Cristina; González, Raquel; Suárez, María Dolores; Zarzuelo, Antonio; Sánchez de Medina, Fermín; Martínez-Augustin, Olga

    2015-02-28

    Flavonoids are polyphenolic compounds that are widespread in nature, and consumed as part of the human diet in significant amounts. The aim of the present study was to test the intestinal anti-inflammatory activity of apigenin K, a soluble form of apigenin, in two models of rat colitis, namely the trinitrobenzenesulfonic acid (TNBS) model and the dextran sulphate sodium (DSS) model. Apigenin K (1, 3 and 10 mg/kg; by the oral route; n 4-6 per group) was administered as a pre-treatment to rats with TNBS and DSS colitis, and colonic status was checked by macroscopic and biochemical examination. Apigenin K pre-treatment resulted in the amelioration of morphological signs and biochemical markers in the TNBS model. The results demonstrated a reduction in the inflamed area, as well as lower values of score and colonic weight:length ratio compared with the TNBS group. Myeloperoxidase (MPO) activity was reduced by 30 % (Papigenin K pre-treatment ameliorated morphological signs and biochemical markers in the DSS model. Thus, macroscopic damage was significantly reduced and the colonic weight:length ratio was lowered by approximately 10 %, while colonic MPO and alkaline phosphatase activities were decreased by 35 and 21 %, respectively (PApigenin K pre-treatment also tended to normalise the expression of a number of colonic inflammatory markers (e.g. TNF-α, transforming growth factor-β, IL-6, intercellular adhesion molecule 1 or chemokine (C-C motif) ligand 2). In conclusion, apigenin K is found to have anti-inflammatory effects in two preclinical models of inflammatory bowel disease.

  1. Leg amputation following intramuscular injection of iron dextran in a 32 year old woman

    Directory of Open Access Journals (Sweden)

    Gloria Shalviri

    2015-10-01

    Full Text Available To inform healthcare professionals of a rare serious reaction leading to leg amputation following intramuscular injection of iron dextran and report comments for preventing such reactions.A case of leg amputation following intramuscular injection of iron dextran reported to Iranian Pharmacovigilance Center was reviewed. Patient and reaction data was collected by assessing the reported yellow card, patient chart review and interviewing with patient and physicians. World Health Organization definition for serious reactions was used to determine the seriousness of the reaction. Naranjo algorithm was used to determine probability scale. The probability of the reaction was determined based on questionnaire of Schumock et al. The studied case is classified as a rare and serious but preventable reaction induced by intramuscular injection of iron dextran in a 32 year old woman. The probability of the reaction is appeared to be “probable” based on Naranjo algorithm. It seems that Iron dextran could cause serious and life threatening adverse effects. It is necessary for healthcare professionals to be informed of such rare but serious reaction in order to apply preventive actions.

  2. Stability of ketoprofen-dextran ester prodrugs in homogenates of various segments of pig GI tract

    DEFF Research Database (Denmark)

    Larsen, C.; Jensen, Bodil Hamborg; Olesen, H. P.

    1991-01-01

    Initial velocities of ketoprofen formation from ketoprofen-dextran ester prodrugs incubated in homogenates of various segments of the pig GI-tract were determined. Enzyme-mediated drug release was found in caecum and colon homogenates with their contents, whereas release rates in the stomach...

  3. Study on Thermosensitive Micellization of Dextran-g-PNIPAAm in Aqueous Solutions

    Institute of Scientific and Technical Information of China (English)

    Dan ZHAO; Li Qun WANG; Ke Hua TU; Song Wei TAN

    2006-01-01

    The thermosensitive micellization of dextran-g-PNIPAAm in aqueous solutions has been investigated by fluorescence spectroscopy, dynamic light scattering and transmission electron microscope. The formed polymeric micelles showed different diameters of about 20 nm or 100nm, when the solution temperature was below or above the phase transition temperature.

  4. Phase separation of aqueous mixtures of poly(ethylene oxide) and dextran

    NARCIS (Netherlands)

    Edelman, M.W.; Linden, van der E.; Tromp, R.H.

    2003-01-01

    Abstract: The phase behavior of aqueous mixtures of poly(ethylene oxide) (PEO) and dextran is studied as a function of the polymer concentration, the PEO molar mass, and temperature. The molar mass distributions of the two polymers in the coexisting phases are measured. From the temperature dependen

  5. Chitosan-dextran sulfate hydrogels as a potential carrier for probiotics

    DEFF Research Database (Denmark)

    Yucel Falco, Cigdem; Falkman, Peter; Risbo, Jens

    2017-01-01

    Physical and chemical (crosslinked with genipin) hydrogels based on chitosan and dextran sulfate were developed and characterized as novel bio-materials suitable for probiotic encapsulation. The swelling of the hydrogels was dependent on the composition and weakly influenced by the pH of the media...

  6. Synthesis and characterization of Schiff base contained dextran microgels in water-in-oil inverse microemulsion.

    Science.gov (United States)

    Su, Hongying; Jia, Qingming; Shan, Shaoyun

    2016-11-05

    Polysaccharide-based microgels with high water content, excellent biocompatibility and controllable particle size have been widely studied as ideal candidates for drug release and delivery. In this study, microgels based on dextran were developed via the Schiff base formation between aldehyded dextran and ethylenediamine in a water-in-oil (W/O) microemulsion. Particle size of the resulted microgel was controllable between 800 and 1100nm by modulating the amount of the employed co-surfactants (Span 80/Tween 80). Furthermore, fluoresceins (e.g., aminofluorescein) and drugs (e.g., doxorubicin) with free amino groups can be conjugated onto the network of the dextran-based microgel via Schiff base linkages. Since the Schiff base linkages are degradable via hydrolysis and their stability decreases with the environmental pH decreases, the resulted Schiff bases contained microgel showed a pH dependent degradation profile. These results indicated that the pH-sensitive microgel based on dextran could be used as promising drug delivery systems for biomedical applications.

  7. 77 FR 50121 - Hospira, Inc.; Withdrawal of Approval of a New Drug Application for DEXTRAN 70

    Science.gov (United States)

    2012-08-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Hospira, Inc.; Withdrawal of Approval of a New Drug... Drug Administration (FDA) is withdrawing approval of a new drug application (NDA) for DEXTRAN 70...

  8. Self-assembling microsphere-based dextran hydrogels for pharmaceutical applications

    NARCIS (Netherlands)

    Van Tomme, S.R.

    2007-01-01

    In this thesis novel self-assembling hydrogels, based on physical interactions between dextran microgels, potentially suitable for controlled drug delivery and tissue engineering, are presented. Two different approaches to self-assemble the hydrogels were investigated: ionic interactions and hydroph

  9. Practical Use of Nitrite and Basis for Dosage in the Manufacture of Meat Products

    DEFF Research Database (Denmark)

    Adler-Nissen, Jens; Ekgreen, Maria Helbo; Risum, Jørgen

    The use of nitrite (NaNO2) in the manufacture of salted (cured) meat products has a long tradition in the industry, dating back to the early twentieth century. Nitrite serves several technological purposes, primarily by the formation of a stable red colour in the meat and the inhibition....... Nitrite also has a desirable anti-oxidant activity and contributes to the formation of pleasant flavours. A systematic literature review on the function and use of nitrite in meat leads to a tentative first conclusion that if the level of nitrite added to meat products is sufficient to protect against...... number of experiments were conducted in Denmark in collaboration with the Danish meat manufacturing industry in 1981-1983. Wiltshire bacon and certain canned products largely for export were not investigated in this study, however. The adverse effects of nitrite can mainly be ascribed to the risk...

  10. The effect of environmental hypercapnia and size on nitrite toxicity in the striped catfish (Pangasianodon hypophthalmus)

    DEFF Research Database (Denmark)

    Hvas, Malthe; Damsgaard, Christian; Gam, Le Thi Hong

    2016-01-01

    Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl- for uptake at the branchial HCO3-/Cl- exchanger...... in the initial phase of acid-base compensation. Overall, longer term environmental hypercapnia does not protect against nitrite uptake in P. hypophthalmus, but instead enhances it. In addition, we observed a significant size effect in nitrite accumulation, where large fish attained plasma [nitrite] above...... the ambient concentration, while small fish did not. Small P. hypophthalmus instead had significantly higher plasma [nitrate], and haemoglobin concentrations, revealing greater capacity for detoxifying nitrite by oxidising it to nitrate....

  11. Nitrites and nitrates in the human diet: Carcinogens or beneficial hypotensive agents?

    Science.gov (United States)

    Butler, Anthony

    2015-06-05

    The presence of nitrite in the human diet was thought to constitute a hazard as secondary nitrosamines are known to cause gastric cancers. Recent publications on the physiology of serum nitrite have been consulted. Nitrite is added to some foodstuffs as an antibotulinum agent. The epidemiological evidence that nitrite causes gastric ulcers is weak. On the other hand, evidence that the presence of nitrite in serum lowers blood pressure is strong. This allows us to explain why a Tang dynasty treatment for angina, given in a Dunhuang medical manuscript, can be successful. The presence of nitrite in food is free of danger and a diet high in nitrate is beneficial to the health. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Hydroxyethyl starch as a substitute for dextran 40 for thawing peripheral blood progenitor cell products.

    Science.gov (United States)

    Zhu, Fenlu; Heditke, Sarah; Kurtzberg, Joanne; Waters-Pick, Barbara; Hari, Parameswaran; Margolis, David A; Keever-Taylor, Carolyn A

    2015-12-01

    Removing DMSO post-thaw results in: reduced infusion reactions, improved recovery and stability of viable CD34+ cells. Validated methods use 5%-8.3% Dextran 40 with 2.5%-4.2% HSA for this purpose. Recent shortages of clinical grade Dextran require identification of suitable alternatives. PBPC were used to compare a standard 2X wash medium of 5 parts 10% Dextran 40 in saline (DEX) with 1 part 25% HSA (8.3% DEX/ 4.2% HSA) with Hydroxyethyl Starch (HES)-based solutions. Cells in replicate bags were diluted with an equal volume of wash solution, equilibrated 5 minutes, the bag filled with wash medium, pelleted and the supernatant expressed. Bags were restored to the frozen volume in wash medium and tested by single platform flow cytometry and CFU. Total viability, viable TNC, MNC, and CD34+ cell recovery, and CD34+ cell viability were compared immediately post-thaw and after 90 minutes. 5.2% HES/4.2% HSA did not differ from our standard in CD34 recovery or viability. Due to concerns that high concentrations of HES could affect renal function we tested 0.6% HES/2.5% HSA resulting in significantly poorer CD34 recovery and viability. Results improved using 2.4% HES/4.2% HSA and when 0.6% HES/4.2%HSA was used no significant differences were seen. CFU assays confirmed no differences between the standard dextran arm and HES at 2.4% or 0.6% so long as HSA was at 4.2%. We conclude that HES from 0.6% to 5.2% with 4.2% HSA is a suitable substitute for Dextran 40 as a reconstitution/washing medium for PBPC products. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  13. Long-Term Effects of Bone Marrow-Derived Mesenchymal Stem Cells in Dextran Sulfate Sodium-Induced Murine Chronic Colitis.

    Science.gov (United States)

    Lee, Hyun Jung; Oh, Sun-Hee; Jang, Hui Won; Kwon, Ji-Hee; Lee, Kyoung Jin; Kim, Chung Hee; Park, Soo Jung; Hong, Sung Pil; Cheon, Jae Hee; Kim, Tae Il; Kim, Won Ho

    2016-05-23

    Bone marrow-derived mesenchymal stem cells (BM-MSCs) have shown beneficial effects in experimental colitis models, but the underlying mechanisms are not fully understood. We investigated the long-term effects of BM-MSCs, particularly in mice with chronic colitis. Chronic colitis was induced by administering 3% dextran sulfate sodium (DSS) in a series of three cycles. BMMSCs were injected intravenously into DSS-treated mice three times during the first cycle. On day 33, the therapeutic effects were evaluated with clinicopathologic profiles and histological scoring. Inflammatory mediators were measured with real-time polymerase chain reaction. Systemic infusion of BM-MSCs ameliorated the severity of colitis, and body weight restoration was significantly promoted in the BMMSC- treated mice. In addition, BM-MSC treatment showed a sustained beneficial effect throughout the three cycles. Microscopic examination revealed that the mice treated with BM-MSCs had fewer inflammatory infiltrates, a lesser extent of inflammation, and less crypt structure damage compared with mice with DSS-induced colitis. Anti-inflammatory cytokine levels of interleukin-10 were significantly increased in the inflamed colons of BM-MSC-treated mice compared with DSS-induced colitis mice. Systemic infusion of BM-MSCs at the onset of disease exerted preventive and rapid recovery effects, with long-term immunosuppressive action in mice with repeated DSS-induced chronic colitis.

  14. Cynanchum wilfordii Polysaccharides Suppress Dextran Sulfate Sodium-Induced Acute Colitis in Mice and the Production of Inflammatory Mediators from Macrophages

    Directory of Open Access Journals (Sweden)

    Chang-Won Cho

    2017-01-01

    Full Text Available We recently reported the immune-enhancing effects of a high-molecular-weight fraction (HMF of CW in macrophages and immunosuppressed mice, and this effect was attributed to a crude polysaccharide. As polysaccharides may also have anti-inflammatory functions, we investigated the anti-inflammatory effects and related molecular mechanisms of a crude polysaccharide (HMFO obtained from HMF of CW in mice with dextran sulfate sodium- (DSS- induced colitis and in lipopolysaccharide-induced RAW 264.7 macrophages. HMFO ameliorated the pathological characteristics of colitis and significantly reduced production of proinflammatory cytokines in the serum. Histological analysis indicated that HMFO improved the signs of histological damage such as abnormal crypts, crypt loss, and inflammatory cell infiltration induced by DSS. In addition, HMFO inhibited iNOS and COX-2 protein expression, as well as phosphorylated NF-κB p65 levels in the colon tissue of mice with DSS-induced colitis. In macrophages, HMFO inhibited several cytokines and enzymes involved in inflammation such as prostaglandin E2, nitric oxide, tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 by attenuating nuclear factor-κB (NF-κB and mitogen-activated protein kinases. HMFO attenuated inflammation both in vitro and in vivo, primarily by inhibiting NF-κB activation. Our findings indicate that HMFO is a promising remedy for treating inflammatory bowel diseases, such as colitis.

  15. High impact of in situ dextran coating on biocompatibility, stability and magnetic properties of iron oxide nanoparticles.

    Science.gov (United States)

    Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

    2017-06-01

    Biocompatible ferrofluids based on dextran coated iron oxide nanoparticles were fabricated by conventional co-precipitation method. The experimental results show that the presence of dextran in reaction medium not only causes to the appearance of superparamagnetic behavior but also results in significant suppression in saturation magnetization of dextran coated samples. These results can be attributed to size reduction originated from the role of dextran as a surfactant. Moreover, weight ratio of dextran to magnetic nanoparticles has a remarkable influence on size and magnetic properties of nanoparticles, so that the sample prepared with a higher weight ratio of dextran to nanoparticles has the smaller size and saturation magnetization compare with the other samples. In addition, the ferrofluids containing such nanoparticles have an excellent stability at physiological pH for several months. Furthermore, the biocompatibility studies reveal that surface modification of nanoparticles by dextran dramatically decreases the cytotoxicity of bare nanoparticles and consequently improves their potential application for diagnostic and therapeutic purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Derivatization of Dextran for Multiply Charged Ion Formation and Electrospray Ionization Time-of-Flight Mass Spectrometric Analysis

    Science.gov (United States)

    Tapia, Jesus B.; Hibbard, Hailey A. J.; Reynolds, Melissa M.

    2017-10-01

    We present the use of a simple, one-pot derivatization to allow the polysaccharide dextran to carry multiple positive charges, shifting its molecular weight distribution to a lower m/ z range. We performed this derivatization because molecular weight measurements of polysaccharides by mass spectrometry are challenging because of their lack of readily ionizable groups. The absence of ionizable groups limits proton abstraction and suppresses proton adduction during the ionization process, producing mass spectra with predominantly singly charged metal adduct ions, thereby limiting the detection of large polysaccharides. To address this challenge, we derivatized dextran T1 (approximately 1 kDa) by attaching ethylenediamine, giving dextran readily ionizable, terminal amine functional groups. The attached ethylenediamine groups facilitated proton adduction during the ionization process in positive ion mode. Using the low molecular weight dextran T1, we tracked the number of ethylenediamine attachments by measuring the mass shift from underivatized to derivatized dextran T1. Using electrospray ionization time-of-flight mass spectrometry, we observed derivatized dextran chains ranging from two to nine glucose residues with between one and four attachments/charges. Our success in shifting derivatized dextran T1 toward the low m/ z range suggests potential for this derivatization as a viable route for analysis of high molecular weight polysaccharides using electrospray ionization time-of-flight mass spectrometry. [Figure not available: see fulltext.

  17. Modelling nitrite dynamics and associated feedback processes in the Benguela oxygen minimum zone

    Science.gov (United States)

    Mashifane, T. B.; Vichi, M.; Waldron, H. N.; Machu, E.; Garçonc, V.

    2016-08-01

    Understanding nitrite dynamics in oxygen minimum zones (OMZs) is a challenge as it represents an intermediary nitrogen species with a short turnover time. Nitrite is also reduced to nitrogen in OMZs, preventing its accumulation. This creates difficulties in detecting nitrite with colorimetric methods as concentrations may occur below detection limits in some regions. Nitrite concentrations are key to understanding intermediate nitrogen processes and their implication for nitrogen loss in OMZs. A coupled physical-biogeochemical model is applied in the Benguela OMZ to study nitrite dynamics and its associated feedback processes. Simulated results show occurrence of primary and secondary nitrite maxima in the Benguela shelf waters. The primary nitrite maxima in the Benguela are attributed to nitrification and nitrate assimilation as they occur in association with the nitracline. Secondary nitrite maxima accumulate in the Angola-Benguela Front (ABF) OMZ and are attributed to denitrification. The secondary nitrite maxima are consumed by anaerobic ammonium oxidation (anammox) off Walvis Bay. Nitrite maxima are restricted to the shelf off Walvis Bay and advected offshore in the ABF region. Interchanges between the poleward South Atlantic Central Water (SACW) and the equatorward, well-aerated Eastern South Atlantic Central Water (ESACW) drive the seasonality of nitrogen processes in the Benguela. Subsequent nitrite reduction in the Benguela OMZ leads to nitrous oxide production, with high concentrations occurring in the ABF region as a result of nitrification and denitrification. Off Walvis Bay, nitrous oxide production is low since nitrite is consumed by anammox. Nitrous oxide production occurs in thermocline, intermediate and deeper water masses in the ABF region. High N fluxes in the Benguela are attributed to nitrification as compared to anammox and denitrification. Results from this study demonstrate the role of intermediate nitrogen species in nitrogen feedback

  18. Measurement of nitrite reductase in leaf tissue of Vigna mungo : A new method.

    Science.gov (United States)

    Srivastava, R C; Bose, B; Mukerji, D; Mathur, S N; Srivastava, H S

    1979-12-01

    The enzyme nitrite reductase (EC 1.6.6.4) is generally assayed in terms of disappearance of nitrite from the assay medium. We describe a technique which allowed estimation of the enzyme level in leaf tissues of Vigna mungo (L). Hepper in terms of the release of the product (NH3) of the enzyme reaction. The technique is offered as an alternative, possibly more convenient method for assay of nitrite reductase in plant tissue in vivo.

  19. Nitrate reduction to nitrite, nitric oxide and ammonia by gut bacteria under physiological conditions.

    Science.gov (United States)

    Tiso, Mauro; Schechter, Alan N

    2015-01-01

    The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO) and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in which the microbiome

  20. Nitrogen removal and electricity production at a double-chamber microbial fuel cell with cathode nitrite denitrification.

    Science.gov (United States)

    Yu, Yangyang; Zhao, Jianqiang; Wang, Sha; Zhao, Huimin; Ding, Xiaoqian; Gao, Kun

    2017-02-17

    Double-chamber microbial fuel cell was applied to investigate the performance of the electricity production and nitrite denitrification through feeding nitrite into the cathode. Factors influencing denitrification performance and power production, such as external resistance, influent nitrite concentration and Nitrite Oxygen Bacteria inhibitors, were studied. The results show that when the concentration of nitrite nitrogen and external resistance were 100 mg L(-1) and 10 Ω, respectively, the nitrite denitrification reached the best state. The NaN3 can inhibit nitrite oxidation effectively; meanwhile, the nitrite denitrification with N2O as the final products was largely improved. The [Formula: see text] was reduced to [Formula: see text], causing the cathode denitrification coulombic efficiency to exceed 100%. In chemoautotrophic bio-nitrification, microorganisms may utilize H2O to oxidize nitrite under anaerobic conditions. Proteobacteria might play a major role in the process of denitrification in MFC.

  1. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  2. Nitrite toxicity of Litopenaeus vannamei in water containing low concentrations of sea salt or mixed salts

    Science.gov (United States)

    Sowers, A.; Young, S.P.; Isely, J.J.; Browdy, C.L.; Tomasso, J.R.

    2004-01-01

    The uptake, depuration and toxicity of environmental nitrite was characterized in Litopenaeus vannamei exposed in water containing low concentrations of artificial sea salt or mixed salts. In 2 g/L artificial sea salts, nitrite was concentrated in the hemolymph in a dose-dependent and rapid manner (steady-state in about 2 d). When exposed to nitrite in 2 g/L artificial sea salts for 4 d and then moved to a similar environment without added nitrite, complete depuration occurred within a day. Increasing salinity up to 10 g/L decreased uptake of environmental nitrite. Nitrite uptake in environments containing 2 g/L mixed salts (combination of sodium, potassium, calcium and magnesium chlorides) was similar to or lower than rates in 2 g/L artificial sea salt. Toxicity was inversely related to total dissolved salt and chloride concentrations and was highest in 2 g/L artificial sea salt (96-h medial lethal concentration = 8.4 mg/L nitrite-N). Animals that molted during the experiments did not appear to be more susceptible to nitrite than animals that did not molt. The shallow slope of the curve describing the relationship between toxicity and salinity suggests that management of nitrite toxicity in low-salinity shrimp ponds by addition of more salts may not be practical. ?? Copyright by the World Aquaculture Society 2004.

  3. Role of blood and vascular smooth muscle in the vasoactivity of nitrite.

    Science.gov (United States)

    Liu, Taiming; Schroeder, Hobe J; Barcelo, Lisa; Bragg, Shannon L; Terry, Michael H; Wilson, Sean M; Power, Gordon G; Blood, Arlin B

    2014-10-01

    Recent evidence from humans and rats indicates that nitrite is a vasodilator under hypoxic conditions by reacting with metal-containing proteins to produce nitric oxide (NO). We tested the hypothesis that near-physiological concentrations of nitrite would produce vasodilation in a hypoxia- and concentration-dependent manner in the hind limb of sheep. Anesthetized sheep were instrumented to measure arterial blood pressure and femoral blood flows continuously in both hind limbs. Nitrite was infused into one femoral artery to raise the nitrite concentration in the femoral vein by 10 to 15-fold while the sheep breathed 50%, 14% or 12% oxygen in inspired air. In contrast to reports in humans and rats, the nitrite infusion had no measurable effect on mean femoral blood flows or vascular conductances, regardless of inspired O2 levels. In vitro experiments showed no significant difference in the release of NO from nitrite in sheep and human red blood cells. Further experiments demonstrated nitrite is converted to NO in rat artery homogenates faster than sheep arteries, and that this source of NO production is attenuated in the presence of a heme oxidizer. Finally, western blots indicate that concentrations of the heme-containing protein cytoglobin, but not myoglobin, are markedly lower in sheep arteries compared with rats. Overall, the results demonstrate that nitrite is not a physiological vasodilator in sheep. This is likely due to a lack of conversion of nitrite to NO within the vascular smooth muscle, perhaps due to deficient amounts of the heme-containing protein cytoglobin.

  4. Role of Nitrite in Processed Meat Products and its Degradation during their Storage

    Directory of Open Access Journals (Sweden)

    ILIRJANA BOCI

    2014-06-01

    Full Text Available This paper represents the analytical data of nitrite level obtained from the experimental work done on meat processed samples taken from a meat processing plant in Tirana. There has been a long debate and health concern about the nitrite content in meat products. Nitrite is added to e.g. sausages, and hams and other meat products to preserve these products and keep them free from dangerous bacteria. Among the aims are preventing botulism, a dangerous food poison. But also it’s important to use the smallest possible amount of nitrite as a preservative because nitrite in meat can also form nitrosamines, which can damage the health. That’s why the role of nitrite in processed meat and its recommended level conform to new EC Regulations are given in the introduction part of this paper. It is important that the nitrite level be monitored during all the processing steps up to the end consumers. This makes the objective of this paper. It gives the analytical data on nitrite level on meat processed samples taken and tested during their storage and ripening period of time. Different kinds of meat products are taken and tested to evaluate the influence of various parameters (storage time, time until to the end consumers, various kinds of packing in the degradation rate of ingoing nitrite.

  5. METHOD FOR NITRATE DETERMINATION IN WATER IN THE PRESENCE OF NITRITE

    Directory of Open Access Journals (Sweden)

    Maria Sandu

    2014-12-01

    Full Text Available The study relates to determination of nitrate in presence of nitrite in water and can be used in the quality monitoring of natural water (surface and groundwater, drinking water, water from fish farms and public aquaria where autonomous filters is used. The nature and quantity of reagents used have insignificant impact on natural waters and sewages. According to the investigation, the method includes the removal of nitrite from the solution/water with sulfaminic acid, the nitrate ion reduction to nitrite using a reducing mixture that contains Na2SO4 and zinc dust in ratio of 100:5 and determining the nitrite with the Griess reagent.

  6. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  7. Microbial competition among anammox bacteria in nitrite-limited bioreactors

    KAUST Repository

    Zhang, Lei

    2017-08-26

    Phylogenetically diverse anammox bacteria have been detected in most of anoxic natural and engineered ecosystems and thus regarded as key players in the global nitrogen cycle. However, ecological niche differentiation of anammox bacteria remains unresolved despite its ecological and practical importance. In this study, the microbial competitions for a common substrate (nitrite) among three anammox species (i.e. “Candidatus Brocadia sinica”, “Candidatus Jettenia caeni” and “Candidatus Kuenenia stuttgartiensis”) were systematically investigated in nitrite-limited gel-immobilized column reactors (GICR) and membrane bioreactors (MBRs) under different nitrogen loading rates (NLRs). 16 S rRNA gene-based population dynamics revealed that “Ca. J. caeni” could proliferate only at low NLRs, whereas “Ca. B. sinica” outcompeted other two species at higher NLRs in both types of reactors. Furthermore, FISH analysis revealed that “Ca. J. caeni” was mainly present as spherical microclusters at the inner part (low NO2− environment), whereas “Ca. B. sinica” was present throughout the gel beads and granules. This spatial distribution supports the outcomes of the competition experiments. However, the successful competition of “Ca. J. caeni” at low NLR could not be explained with the Monod model probably due to inaccuracy of kinetic parameters such as half saturation constant (Ks) for nitrite and a difference in the maintenance rate (m). In addition, the growth of “Ca. K. stuttgartiensis” could not be observed in any experimental conditions, suggesting possible unknown factor(s) is missing. Taken together, NLR was one of factors determining ecological niche differentiation of “Ca. B. sinica” and “Ca. J. caeni”.

  8. Low concentrations of human neutrophil peptide ameliorate experimental murine colitis.

    Science.gov (United States)

    Maeda, Takuro; Sakiyama, Toshio; Kanmura, Shuji; Hashimoto, Shinichi; Ibusuki, Kazunari; Tanoue, Shiroh; Komaki, Yuga; Arima, Shiho; Nasu, Yuichiro; Sasaki, Fumisato; Taguchi, Hiroki; Numata, Masatsugu; Uto, Hirofumi; Tsubouchi, Hirohito; Ido, Akio

    2016-12-01

    Human neutrophil peptides (HNPs) not only have antimicrobial properties, but also exert multiple immunomodulatory effects depending on the concentration used. We have previously demonstrated that the intraperitoneal administration of high-dose HNP-1 (100 µg/day) aggravates murine dextran sulfate sodium (DSS)-induced colitis, suggesting a potential pro-inflammatory role for HNPs at high concentrations. However, the role of low physiological concentrations of HNPs in the intestinal tract remains largely unknown. The aim of this study was to examine the effects of low concentrations of HNPs on intestinal inflammation. We first examined the effects of the mild transgenic overexpression of HNP-1 in DSS-induced colitis. HNP-1 transgenic mice have plasma HNP-1 levels similar to the physiological concentrations in human plasma. Compared to wild-type mice treated with DSS, HNP-1 transgenic mice treated with DSS had significantly lower clinical and histological scores, and lower colonic mRNA levels of pro-inflammatory cytokines, including interleukin (IL)-1β and tumor necrosis factor (TNF)-α. We then injected low-dose HNP-1 (5 µg/day) or phosphate-buffered saline (PBS) intraperitoneally into C57BL/6N and BALB/c mice administered DSS. The HNP-1-treated mice exhibited significantly milder colitis with reduced expression levels of pro-inflammatory cytokines compared with the PBS-treated mice. Finally, we examined the in vitro effects of HNP-1 on the expression of cytokines associated with macrophage activation. Low physiological concentrations of HNP-1 did not significantly affect the expression levels of IL-1β, TNF-α, IL-6 or IL-10 in colonic lamina propria mononuclear cells activated with heat-killed Escherichia coli, suggesting that the anti-inflammatory effects of HNP-1 on murine colitis may not be exerted by direct action on intestinal macrophages. Collectively, our data demonstrated a biphasic dose-dependent effect of HNP-1 on DSS-induced colitis: an

  9. Novel magnetic nanoparticles coated by benzene- and β-cyclodextrin-bearing dextran, and the sorption of polycyclic aromatic hydrocarbon

    DEFF Research Database (Denmark)

    Cho, Eunae; Tahir, Muhammad Nazir; Min Choi, Jae

    2015-01-01

    We present the synthesis of novel magnetic nanoparticles functionalized by benzene- and β-cyclodextrin-derivatized dextran. The grafting strategy was based on the [alkynyl-iron] cluster in the modified dextrans, which were prepared by click reaction from alkyne-modified dextran and benzyl azide...... or mono-6-O-deoxy-monoazido β-cyclodextrin. Characterization was then carried out by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. Using the developed magnetic nanoparticles...... to be significant. Furthermore, the polysaccharide derivative-coated magnetic adsorbents could be recovered by an external magnet for reuse....

  10. Plecanatide and dolcanatide, novel guanylate cyclase-C agonists, ameliorate gastrointestinal inflammation in experimental models of murine colitis

    Institute of Scientific and Technical Information of China (English)

    Kunwar; Shailubhai; Vaseem; Palejwala; Krishna; Priya; Arjunan; Sayali; Saykhedkar; Bradley; Nefsky; John; A; Foss; Stephen; Comiskey; Gary; S; Jacob; Scott; E; Plevy

    2015-01-01

    AIM: To evaluate the effect of orally administeredplecanatide or dolcanatide, analogs of uroguanylin, on amelioration of colitis in murine models.METHODS: The cyclic guanosine monophosphate(cG MP) stimulatory potency of plecanatide and dolcanatide was measured using a human colon carcinoma T84 cellbased assay. For animal studies all test agents were formulated in phosphate buffered saline. Sulfasalazine or 5-amino salicylic acid(5-ASA) served as positive controls. Effect of oral treatment with test agents on amelioration of acute colitis induced either by dextran sulfate sodium(DSS) in drinking water or by rectal instillation of trinitrobenzene sulfonic(TNBS) acid, was examined in BALB/c and/or BDF1 mice. Additionally, the effect of orally administered plecanatide on the spontaneous colitis in T-cell receptor alpha knockout(TCRα-/-) mice was also examined. Amelioration of colitis was assessed by monitoring severity of colitis, disease activity index and by histopathology. Frozen colon tissues were used to measure myeloperoxidase activity.RESULTS: Plecanatide and dolcanatide are structurally related analogs of uroguanylin, which is an endogenous ligand of guanylate cyclase-C(GC-C). As expected from the agonists of GC-C, both plecanatide and dolcanatide exhibited potent cG MP-stimulatory activity in T84 cells. Once-daily treatment by oral gavage with either of these analogs(0.05-0.5 mg/kg) ameliorated colitis in both DSS and TNBS-induced models of acute colitis, as assessed by body weight, reduction in colitis severity(P < 0.05) and disease activity index(P < 0.05). Amelioration of colitis by either of the drug candidates was comparable to that achieved by orally administered sulfasalazine or 5-ASA. Plecanatide also effectively ameliorated colitis in TCRα-/- mice, a model of spontaneous colitis. As dolcanatide exhibited higher resistance to proteolysis in simulated gastric and intestinal juices, it was selected for further studies. CONCLUSION: This is the first

  11. The effect of environmental hypercapnia and size on nitrite toxicity in the striped catfish (Pangasianodon hypophthalmus).

    Science.gov (United States)

    Hvas, Malthe; Damsgaard, Christian; Gam, Le Thi Hong; Huong, Do Thi Thanh; Jensen, Frank B; Bayley, Mark

    2016-07-01

    Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl(-) for uptake at the branchial HCO3(-)/Cl(-) exchanger, causing a drastic reduction in the blood oxygen carrying capacity through the formation of methaemoglobin and nitrosylhaemoglobin. Environmental hypercapnia induces a respiratory acidosis where the branchial HCO3(-)/Cl(-) exchange activity is reduced in order to retain HCO3(-) for pH recovery, which should lead to a reduced nitrite uptake. To assess the effect of hypercapnia on nitrite uptake, fish were cannulated in the dorsal aorta, allowing repeated blood sampling for measurements of haemoglobin derivatives, plasma ions and acid-base status during exposure to 0.9mM nitrite alone and in combination with acute and 48h acclimated hypercapnia over a period of 72h. Nitrite uptake was initially reduced during the hypercapnia-induced acidosis, but after pH recovery the situation was reversed, resulting in higher plasma nitrite concentrations and lower functional haemoglobin levels that eventually caused mortality. This suggests that branchial HCO3(-)/Cl(-) exchange activity is reduced only during the initial acid-base compensation, but subsequently increases with the greater availability of internal HCO3(-) counter-ions as pH is compensated. The data further suggest that branchial Na(+)/H(+) exchange plays a significant role in the initial phase of acid-base compensation. Overall, longer term environmental hypercapnia does not protect against nitrite uptake in P. hypophthalmus, but instead enhances it. In addition, we observed a significant size effect in nitrite accumulation, where large fish attained plasma [nitrite] above the ambient concentration, while small fish did not. Small P. hypophthalmus instead had significantly higher plasma [nitrate], and haemoglobin

  12. Excessive nitrite affects zebrafish valvulogenesis through yielding too much NO signaling.

    Directory of Open Access Journals (Sweden)

    Junbo Li

    Full Text Available Sodium nitrite, a common food additive, exists widely not only in the environment but also in our body. Excessive nitrite causes toxicological effects on human health; however, whether it affects vertebrate heart valve development remains unknown. In vertebrates, developmental defects of cardiac valves usually lead to congenital heart disease. To understand the toxic effects of nitrite on valvulogenesis, we exposed zebrafish embryos with different concentrations of sodium nitrite. Our results showed that sodium nitrite caused developmental defects of zebrafish heart dose dependently. It affected zebrafish heart development starting from 36 hpf (hour post fertilization when heart initiates looping process. Comprehensive analysis on the embryos at 24 hpf and 48 hpf showed that excessive nitrite did not affect blood circulation, vascular network, myocardium and endocardium development. But development of endocardial cells in atrioventricular canal (AVC of the embryos at 48 hpf was disrupted by too much nitrite, leading to defective formation of primitive valve leaflets at 76 hpf. Consistently, excessive nitrite diminished expressions of valve progenitor markers including bmp4, has2, vcana and notch1b at 48 hpf. Furthermore, 3', 5'-cyclic guanosine monophosphate (cGMP, downstream of nitric oxide (NO signaling, was increased its level significantly in the embryos exposed with excessive nitrite and microinjection of soluble guanylate cyclase inhibitor ODQ (1H-[1], [2], [4]Oxadiazolo[4,3-a] quinoxalin-1-one, an antagonist of NO signaling, into nitrite-exposed embryos could partly rescue the cardiac valve malformation. Taken together, our results show that excessive nitrite affects early valve leaflet formation by producing too much NO signaling.

  13. Acrylic microspheres-based optosensor for visual detection of nitrite.

    Science.gov (United States)

    Noor, Nur Syarmim Mohamed; Tan, Ling Ling; Heng, Lee Yook; Chong, Kwok Feng; Tajuddin, Saiful Nizam

    2016-09-15

    A new optosensor for visual quantitation of nitrite (NO2(-)) ion has been fabricated by physically immobilizing Safranine O (SO) reagent onto a self-adhesive poly(n-butyl acrylate) [poly(nBA)] microspheres matrix, which was synthesized via facile microemulsion UV lithography technique. Evaluation and optimization of the optical NO2(-) ion sensor was performed with a fiber optic reflectance spectrophotometer. Scanning electron micrograph showed well-shaped and smooth spherical morphology of the poly(nBA) microspheres with a narrow particles size distribution from 0.6 μm up to 1.8 μm. The uniform size distribution of the acrylic microspheres promoted homogeneity of the immobilized SO reagent molecules on the microspheres' surfaces, thereby enhanced the sensing response reproducibility (<5% RSD) with a linear range obtained from 10 to 100 ppm NO2(-) ion. The micro-sized acrylic immobilization matrix demonstrated no significant barrier for diffusion of reactant and product, and served as a good solid state ion transport medium for reflectometric nitrite determination in food samples.

  14. STRESS INDUCED NITROGEN DIFFUSION IN NITRITED CoCr ALLOY

    Directory of Open Access Journals (Sweden)

    AKVILĖ PETRAITIENĖ

    2015-03-01

    Full Text Available In the present study the nitrogen transport mechanism in plasma nitrited CoCr alloy at moderate temperature ( 400ºC is explained by non-Fickian diffusion model. This mechanism is considered by stress induced diffusion model. The model involves diffusion of nitrogen induced by internal stresses created during nitriding process. The model considers the diffusion of nitrogen in the presence of  internal stresses gradient induced by penetrating nitrogen as the next driving force of diffusion after concentration gradient. This model is commonly used for analysis of stainless steel nitriding, however, in this work it is shown that the same nitrogen penetration mechanism takes place in CoCr alloy. For mathematical description of stress induced diffusion process the equation of baro-diffusion is used which involves concentration dependant baro-diffusion concentration. For calculation of stress gradient it is assumed that stress depth profile linearly relates with nitrogen concentration depth profile. The fitting is done using experimental curves of nitrogen depth profiles for medical grade CoCr alloy (ISO 5831-12 nitrited at 400 ºC temperature. The experimental curves are taken from literature. The nitriding duration was 2h, 6h, 20h. Calculated nitrogen depth profiles in CoCr alloy are in good agreement with experimental nitrogen depth profiles.  The diffusion coefficient D is found from fitting of experimental data.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5711

  15. Sugar-driven prebiotic synthesis of ammonia from nitrite.

    Science.gov (United States)

    Weber, Arthur L

    2010-06-01

    Reaction of 3-5 carbon sugars, glycolaldehyde, and alpha-ketoaldehydes with nitrite under mild anaerobic aqueous conditions yielded ammonia, an essential substrate for the synthesis of nitrogen-containing molecules during abiogenesis. Under the same conditions, ammonia synthesis was not driven by formaldehyde, glyoxylate, 2-deoxyribose, and glucose, a result indicating that the reduction process requires an organic reductant containing either an accessible alpha-hydroxycarbonyl group or an alpha-dicarbonyl group. Small amounts of aqueous Fe(+3) catalyzed the sugar-driven synthesis of ammonia. The glyceraldehyde concentration dependence of ammonia synthesis, and control studies of ammonia's reaction with glyceraldehyde, indicated that ammonia formation is accompanied by incorporation of part of the synthesized ammonia into sugar-derived organic products. The ability of sugars to drive the synthesis of ammonia is considered important to abiogenesis because it provides a way to generate photochemically unstable ammonia at sites of sugar-based origin-of-life processes from nitrite, a plausible prebiotic nitrogen species.

  16. Addition of nitrite enhances the electrochemical defluorination of 2-fluoroaniline.

    Science.gov (United States)

    Feng, Huajun; Liang, Yuxiang; Guo, Kun; Long, Yuyang; Cong, Yanqing; Shen, Dongsheng

    2015-12-30

    This study introduces a novel approach that uses the interaction of pollutants with added nitrite to produce diazonium salts, which cause in situ self-assembly of the pollutants on carbon electrodes, to improve their 2-fluoroaniline (2-FA) defluorination and removal performance. The 2-FA degradation performance, electrode properties, electrochemical properties and degradation pathway were investigated. The reactor containing NO2(-) achieved a 2-FA removal efficiency of 90.1% and a defluorination efficiency of 38% within 48 h, 1.4 and 2.3 times higher than the corresponding results achieved without NO2(-), respectively. The residual NO2(-) was less than 0.5mg/L in the reactor containing added NO2(-), which would not cause serious secondary pollution. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results proved that the carbon anode surface was successfully modified with benzene polymer, and electrochemical tests confirmed that the electrochemical activity of the modified anode was enhanced significantly. The C-F bond was weakened by the effect of the positive charge of the benzenediazonium groups, and the high electrochemical activity of the carbon anode enhanced the electrochemical performance of the system to accelerate defluorination. Thus, the present electrical method involving nitrite nitrogen is very promising for the treatment of wastewater containing fluoroaniline compounds.

  17. Formation of nanoparticles by cooperative inclusion between (S-camptothecin-modified dextrans and β-cyclodextrin polymers

    Directory of Open Access Journals (Sweden)

    Thorbjørn Terndrup Nielsen

    2015-01-01

    Full Text Available Novel (S-camptothecin–dextran polymers were obtained by “click” grafting of azide-modified (S-camptothecin and alkyne-modified dextrans. Two series based on 10 kDa and 70 kDa dextrans were prepared with a degree of substitution of (S-camptothecin between 3.1 and 10.2%. The binding properties with β-cyclodextrin and β-cyclodextrin polymers were measured by isothermal titration calorimetry and fluorescence spectroscopy, showing no binding with β-cyclodextrin but high binding with β-cyclodextrin polymers. In aqueous solution nanoparticles were formed from association between the (S-camptothecin–dextran polymers and the β-cyclodextrin polymers.

  18. Method 353.4 Determination of Nitrate and Nitrite in Estuarine and Coastal Waters by Gas Segmented Continuous Flow Colorimetric Analysis

    Science.gov (United States)

    This method provides a procedure for determining nitrate and nitrite concentrations in estuarine and coastal waters. Nitrate is reduced to nitrite by cadmium,1-3 and the resulting nitrite determined by formation of an azo dye.4-6

  19. The effects of synthesis method on the physical and chemical properties of dextran coated iron oxide nanoparticles.

    Science.gov (United States)

    Hauser, Anastasia K; Mathias, Ronita; Anderson, Kimberly W; Hilt, J Zach

    2015-06-15

    Iron oxide nanoparticles coated with dextran were synthesized via four variations on the co-precipitation method. The methods ranged from in situ formation of the nanoparticles within the dextran solution to the adsorption of dextran to the nanoparticle surface following nucleation and extensive washing. The timing of the addition of dextran into the reaction mixture was found to greatly influence the physical and chemical properties of the magnetic nanoparticles. Batches of dextran coated iron oxide nanoparticles were synthesized by each method in triplicate, and the nanoparticles were further crosslinked with epichlorohydrin. The properties of the nanoparticles such as size, percentage of dextran coating, stability in solution, crystallinity, and magnetic properties were evaluated. The simultaneous semi-two-step method injected the reducing agent and the dextran solution into the reaction vessel at the same time. This method resulted in the greatest batch-to-batch reproducibility of nanoparticle properties and the least variation in nanoparticles synthesized in the same batch. The two-step method resulted in the greatest variation of the characteristics examined between batches. The one-step method was synthesized with both five grams and one gram of dextran to investigate the effects of solution viscosity on the resulting nanoparticle characteristics. The one-step method with five grams of dextran resulted in nanoparticles with significantly smaller crystal sizes (5.4 ± 1.9 nm) and lower specific adsorption rate (SAR) values (138.4 ± 13.6 W/g) in an alternating magnetic field (58 kA/m, 292 kHz). However, this method resulted in nanoparticles that were very stable in PBS over 12 hours, which is most likely due to the greater dextran coating (60.0 ± 2.7 weight percent). For comparison, the simultaneous semi-two-step method generated nanoparticles 179.2 ± 18.3 nm in diameter (crystal size 12.1 ± 0.2 nm) containing 18.3 ± 1.2 weight percent dextran with a SAR

  20. ANTIOXIDANTS AMELIORATION OF ARSENICAL-INDUCED EFFECTS IN VIVO

    Science.gov (United States)

    Antioxidant amelioration of arsenical-induced effects in vivo. ES Hunter and EH Rogers. Reproductive Toxicology Division, NHEERL, US EPA, RTP, NC. Antioxidants have been reported to ameliorate the effects of many developmental toxicants. We tested the hypothesis that oxi...

  1. Stability and in vitro DNA packaging of bacteriophages: effects of dextrans, sugars, and polyols

    Energy Technology Data Exchange (ETDEWEB)

    Serwer, P. (The Univ. of Texas Health Science Center, San Antonio); Masker, W.E.; Allen, J.L.

    1983-02-01

    Attempts were made to increase the efficiency of infectious particle formation during the in vitro assembly of bacteriophage T7 from procapsids and DNA. It was found that dextrans and some smaller, related compounds (sucrose and sorbitol) increase this efficiency by a factor of 8 to 50. Dextrans also inhibited elevated temperature-induced emptying of DNA from bacteriophages T7, P22, and T4, suggesting that the stimulation of assembly is caused, at least in part, by the stabilization of packaged DNA in capsids. The data indicated that the sugars and polyols can slow DNA emptying from bacteriophages at elevated temperature whether they permeate the bacteriophage capsid or not. In contrast, the data suggested that permeation of some particle, probably a capsid, results in inhibition of in vitro T7 assembly.

  2. Hemodynamic and regional blood flow distribution responses to dextran, hydralazine, isoproterenol and amrinone during experimental cardiac tamponade

    Energy Technology Data Exchange (ETDEWEB)

    Millard, R.W.; Fowler, N.O.; Gabel, M.

    1983-06-01

    Four different interventions were examined in dogs with cardiac tamponade. Infusion of 216 to 288 ml saline solution into the pericardium reduced cardiac output from 3.5 +/- 0.3 to 1.7 +/- 0.2 liters/min as systemic vascular resistance increased from 4,110 +/- 281 to 6,370 +/- 424 dynes . s . cm-5. Left ventricular epicardial and endocardial blood flows were 178 +/- 13 and 220 +/- 12 ml/min per 100 g, respectively, and decreased to 72 +/- 14 and 78 +/- 11 ml/min per 100 g with tamponade. Reductions of 25 to 65% occurred in visceral and brain blood flows and in a composite brain sample. Cardiac output during tamponade was significantly increased by isoproterenol, 0.5 microgram/kg per min intravenously; hydralazine, 40 mg intravenously; dextran infusion or combined hydralazine and dextran, but not by amrinone. Total systemic vascular resistance was reduced by all interventions. Left ventricular epicardial flow was increased by isoproterenol, hydralazine and the hydralazine-dextran combination. Endocardial flow was increased by amrinone and the combination of hydralazine and dextran. Right ventricular myocardial blood flow increased with all interventions except dextran. Kidney cortical and composite brain blood flows were increased by both dextran alone and by the hydralazine-dextran combinations. Blood flow to small intestine was increased by all interventions as was that to large intestine by all except amrinone and hydralazine. Liver blood flow response was variable. The most pronounced hemodynamic and tissue perfusion improvements during cardiac tamponade were effected by combined vasodilation-blood volume expansion with a hydralazine-dextran combination. Isoproterenol had as dramatic an effect but it was short-lived. Amrinone was the least effective intervention.

  3. Capillary Zone Electrophoresis Investigation of Interactions between Granulocyte-colony Stimulating Factor and Dextran Sulfate / Carrageenan Oligosaccharide

    Institute of Scientific and Technical Information of China (English)

    Ai Ye LIANG; Yu Guang DU; Ke Yi WANG; Bing Cheng LIN

    2005-01-01

    The interactions between granulocyte-colony stimulating factor (G-CSF) and dextran sulfate / κ-carrageenan oligosa1ccharide were studied by capillary zone electrophoresis. Dextran sulfate could strongly interact with G-CSF and the complex was detected. The binding constant and stoichiometry were determined to be 1.2x106 (mol/L)-1 and 3:1, respectively. However, the interaction between κ-carrageenan oligosaccharide and G-CSF was not found.

  4. Allosteric control of internal electron transfer in cytochrome cd1 nitrite reductase

    DEFF Research Database (Denmark)

    Farver, Ole; Kroneck, Peter M H; Zumft, Walter G

    2003-01-01

    Cytochrome cd1 nitrite reductase is a bifunctional multiheme enzyme catalyzing the one-electron reduction of nitrite to nitric oxide and the four-electron reduction of dioxygen to water. Kinetics and thermodynamics of the internal electron transfer process in the Pseudomonas stutzeri enzyme have...

  5. Sodium nitrite protects against kidney injury induced by brain death and improves post-transplant function.

    Science.gov (United States)

    Kelpke, Stacey S; Chen, Bo; Bradley, Kelley M; Teng, Xinjun; Chumley, Phillip; Brandon, Angela; Yancey, Brett; Moore, Brandon; Head, Hughston; Viera, Liliana; Thompson, John A; Crossman, David K; Bray, Molly S; Eckhoff, Devin E; Agarwal, Anupam; Patel, Rakesh P

    2012-08-01

    Renal injury induced by brain death is characterized by ischemia and inflammation, and limiting it is a therapeutic goal that could improve outcomes in kidney transplantation. Brain death resulted in decreased circulating nitrite levels and increased infiltrating inflammatory cell infiltration into the kidney. Since nitrite stimulates nitric oxide signaling in ischemic tissues, we tested whether nitrite therapy was beneficial in a rat model of brain death followed by kidney transplantation. Nitrite, administered over 2 h of brain death, blunted the increased inflammation without affecting brain death-induced alterations in hemodynamics. Kidneys were transplanted after 2 h of brain death and renal function followed over 7 days. Allografts collected from nitrite-treated brain-dead rats showed significant improvement in function over the first 2 to 4 days after transplantation compared with untreated brain-dead animals. Gene microarray analysis after 2 h of brain death without or with nitrite therapy showed that the latter significantly altered the expression of about 400 genes. Ingenuity Pathway Analysis indicated that multiple signaling pathways were affected by nitrite, including those related to hypoxia, transcription, and genes related to humoral immune responses. Thus, nitrite therapy attenuates brain death-induced renal injury by regulating responses to ischemia and inflammation, ultimately leading to better post-transplant kidney function.

  6. Electrochemical detection of nitrite based on the polythionine/carbon nanotube modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chunyan, E-mail: dengchunyan@csu.edu.cn [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); College of Pharmaceutical Science, Central South University, Changsha 410083 (China); Chen, Jinzhuo [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); Nie, Zhou [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Yang, Minghui, E-mail: yangminghui@csu.edu.cn [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); Si, Shihui [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China)

    2012-09-30

    In this paper, thionine was electro-polymerized onto the surface of carbon nanotube (CNT)-modified glassy carbon (GC) to fabricate the polythionine (PTH)/CNT/GC electrode. It was found that the electro-reduction current of nitrite was enhanced greatly at the PTH/CNT/GC electrode. It may be demonstrated that PTH was used as a mediator for electrocatalytic reduction of nitrite, and CNTs as an excellent nanomaterial can improve the electron transfer between the electrode and nitrite. Therefore, based on the synergic effect of PTH and CNTs, the PTH/CNT/GC electrode was employed to detect nitrite, and the high sensitivity of 5.81 {mu}A mM{sup -1}, and the detection limit of 1.4 Multiplication-Sign 10{sup -6} M were obtained. Besides, the modified electrode showed an inherent stability, fast response time, and good anti-interference ability. These suggested that the PTH/CNT/GC electrode was favorable and reliable for the detection of nitrite. - Highlights: Black-Right-Pointing-Pointer Polythionine (PTH) was used as a mediator for electrocatalytic reduction of nitrite. Black-Right-Pointing-Pointer Carbon nanotubes (CNTs) improve electron transfer between the electrode and nitrite. Black-Right-Pointing-Pointer The PTH/CNT/glassy carbon electrode showed excellent nitrite detection performance.

  7. Green Alternatives to Nitrates and Nitrites in Meat-based Products-A Review.

    Science.gov (United States)

    Gassara, Fatma; Kouassi, Anne Patricia; Brar, Satinder Kaur; Belkacemi, Khaled

    2016-10-02

    Several food additives are added in food for their preservation to maintain the freshness of food (antioxidants) or to slow down or stop the growth of microorganisms (preservative agents). Nitrites and nitrates are used as preservative agents in meat. Nitrites give a smoked taste, a pinkish color in the meat and protect the consumers against the risk of bacterial deterioration. Their addition is however very limited as, in high dose, it can have risks on human health and the environment. Nitrites may also combine with secondary or tertiary amines to form N-nitroso derivatives. Certain N-nitroso compounds have been shown to produce cancers in a wide range of laboratory animals. Thus, alternatives of nitrates and nitrites are the object of numerous research studies. Alternatives, such as the addition of vitamins, fruits, chemicals products, natural products containing nitrite or spices, which have similar properties of nitrites, are in evaluation. In fact, spices are considered to have several organoleptic and anti-microbial properties which would be interesting to study. Several spices and combinations of spices are being progressively evaluated. This review discusses the sources of nitrites and nitrates, their use as additives in food products, their physicochemical properties, their negatives effects and the use of alternatives of nitrites and nitrates in preserving meat products.

  8. Nitrite in processed meat products in Khartoum, Sudan and dietary intake

    NARCIS (Netherlands)

    Adam, Aziza Hussein Bakheit; Mustafa, Nazik Eltayeb Musa; Rietjens, Ivonne M.C.M.

    2016-01-01

    Nitrite intake from locally processed meat in Khartoum, Sudan was estimated and compared to established safety levels. For this purpose, 90 locally processed meat samples were collected randomly from retail outlets and analysed for nitrite levels according to the British standard 1992 protocol and 3

  9. Autotrophic denitrification for nitrate and nitrite removal using sulfur-limestone

    Institute of Scientific and Technical Information of China (English)

    Weili Zhou; Yeiue Sun; Bingtao Wu; Yue Zhang; Min Huang; Toshiaki Miyanaga; Zhenjia Zhang

    2011-01-01

    Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70 and 100 mg N/L was tested.When treating the low concentration of nitrate- or nitrite-contaminated water (10,40 mg N/L),a high removal rate of about 90% was achieved at the hydraulic retention time (HRT) of 3 hr and temperature of 20-25℃.At the same HRT,50% of the nitrate or nitrite could be removed even at the low temperature of 5-10℃.For the higher concentration nitrate and nitrite (70,100 mg N/L),longer HRT was required.The batch test indicated that influent concentration,HRT and temperature are important factors affecting the denitrification efficiency.Molecular analysis implied that nitrate and nitrite were denitrified into nitrogen by the same microorganisms.The sequential two-stepreactions from nitrate to nitrite and from nitrite to the next-step product might have taken place in the same cell during the autotrophic denitrification process.

  10. In situ ATR-IR study of nitrite hydrogenation over Pd/Al2O3.

    NARCIS (Netherlands)

    Ebbesen, S.D.; Mojet, Barbara; Lefferts, Leonardus

    2008-01-01

    The mechanism of nitrite hydrogenation over a Pd/Al2O3 catalyst layer deposited on a ZnSe internal reflection element was investigated in water using attenuated total reflection infrared spectroscopy. Nitrite hydrogenates to NO(ads), NH2(ads), and NH+4 on the palladium surface. Hydrogenation of

  11. Haematological and ion regulatory effects of nitrite in the air-breathing snakehead fish Channa striata

    DEFF Research Database (Denmark)

    Lefevre, Sjannie; Jensen, Frank Bo; Huong, Do T.T.;

    2012-01-01

    The tolerance and effects of nitrite on ion balance and haematology were investigated in the striped snakehead, Channa striata Bloch 1793, which is an air-breathing fish with reduced gills of importance for aquaculture in South East Asia. C. striata was nitrite tolerant with a 96 h LC50 of 4.7 m...

  12. 77 FR 71006 - Sodium Nitrite Injection and Sodium Thiosulfate Injection Drug Products Labeled for the Treatment...

    Science.gov (United States)

    2012-11-28

    ... HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-N-1134 Sodium Nitrite Injection and Sodium Thiosulfate Injection Drug Products Labeled for the Treatment of Cyanide Poisoning; Enforcement... products containing sodium nitrite labeled for the treatment of cyanide poisoning and unapproved...

  13. Protection of Steel Corrosion in Concrete Members by the Combination of Galvanic Anode and Nitrite Penetration

    OpenAIRE

    Minobu Aoyama; Shinichi Miyazato; Mitsunori Kawamura

    2014-01-01

    Chloride induced-corrosion of steel bars in concrete can make cracks and exfoliation in near-surface regions in reinforced concrete structures. In this paper, we described the basic concept and practice of steel bars corrosion protection method by the combination of galvanic anode (zinc wire) and the penetration of nitrite ions from mortar layers containing a large amount of lithium nitrite.

  14. THE DECOMPOSITION OF DIETHYL PEROXIDE IN THE PRESENCE OF NITRIC OXIDE AND ETHYL NITRITE

    Science.gov (United States)

    substantial amounts. Studies were made of the reactions of ethoxyl radicals (produced by the decomposition of diethyl peroxide at 181 deg C) with ethyl nitrite...and NO. The reaction rate between the ethoxyl radicals and NO was much greater than that between the radicals the nitrite.

  15. Red wine-dependent reduction of nitrite to nitric oxide in the stomach.

    Science.gov (United States)

    Gago, Bruno; Lundberg, Jon O; Barbosa, Rui M; Laranjinha, João

    2007-11-01

    Nitrite may be a source for nitric oxide (*NO), particularly in highly acidic environments, such as the stomach. Diet products contribute also with reductants that dramatically increase the production of *NO from nitrite. Red wine has been attributed health promoting properties largely on basis of the reductive antioxidant properties of its polyphenolic fraction. We show in vitro that wine, wine anthocyanin fraction and wine catechol (caffeic acid) dose- and pH-dependently promote the formation of *NO when mixed with nitrite, as measured electrochemically. The production of *NO promoted by wine from nitrite was substantiated in vivo in healthy volunteers by measuring *NO in the air expelled from the stomach, following consumption of wine, as measured by chemiluminescence. Mechanistically, the reaction involves the univalent reduction of nitrite, as suggested by the formation of *NO and by the appearance of EPR spectra assigned to wine phenolic radicals. Ascorbic and caffeic acids cooperate in the reduction of nitrite to *NO. Moreover, reduction of nitrite is critically dependent on the phenolic structure and nitro-derivatives of phenols are also formed, as suggested by caffeic acid UV spectral modifications. The reduction of nitrite may reveal previously unrecognized physiologic effects of red wine in connection with *NO bioactivity.

  16. Automated simultaneous monitoring of nitrate and nitrite in surface water by sequential injection analysis.

    Science.gov (United States)

    Legnerová, Zlatuse; Solich, Petr; Sklenárová, Hana; Satínský, Dalibor; Karlícek, Rolf

    2002-06-01

    A fully automated procedure based on Sequential Injection Analysis (SIA) methodology for simultaneous monitoring of nitrate and nitrite in surface water samples is described. Nitrite was determined directly using the Griess diazo-coupling reaction and the formed azo dye was measured at 540 nm in the flow cell of the fibre-optic spectrophotometer. Nitrate zone was passed through a reducing mini-column containing copperised-cadmium. After the reduction of nitrate into nitrite the sample was aspirated by flow reversal to the holding coil, treated with the reagent and finally passed through the flow cell. The calibration curve was linear over the range 0.05-1.00 mg N l(-1) of nitrite and 0.50-50.00 mg N l(-1) of nitrate; correlation coefficients were 0.9993 and 0.9988 for nitrite and nitrate, respectively. Detection limits were 0.015 and 0.10 mg N l(-1) for nitrite and nitrate, respectively. The relative standard deviation (RSD) values (n = 3) were 1.10% and 1.32% for nitrite and nitrate, respectively. The total time of one measuring cycle was 250 s, thus the sample throughput was about 14 h(-1). Nitrate and nitrite were determined in the real samples of surface water, and the results have been compared with those obtained by two other flow methods; flow injection analysis based on the same reactions and isotachophoretic determination used in a routine environmental control laboratory.

  17. Low nitrous oxide production in intermittent-feed high performance nitritating reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

    was converted to nitrite, with the average total net N2O production of 2.1 ± 0.7% of the ammonium oxidized. Operation with intermittent feeding appears an effective optimization approach to mitigate N2O emissions from nitritating systems. Net N2O production rates transiently increased with a rise in pH after...

  18. Reducing the Oxidation Level of Dextran Aldehyde in a Chitosan/Dextran-Based Surgical Hydrogel Increases Biocompatibility and Decreases Antimicrobial Efficacy.

    Science.gov (United States)

    Chan, Maggie; Brooks, Heather J L; Moratti, Stephen C; Hanton, Lyall R; Cabral, Jaydee D

    2015-06-16

    A highly oxidized form of a chitosan/dextran-based hydrogel (CD-100) containing 80% oxidized dextran aldehyde (DA-100) was developed as a post-operative aid, and found to significantly prevent adhesion formation in endoscopic sinus surgery (ESS). However, the CD-100 hydrogel showed moderate in vitro cytotoxicity to mammalian cell lines, with the DA-100 found to be the cytotoxic component. In order to extend the use of the hydrogel to abdominal surgeries, reformulation using a lower oxidized DA (DA-25) was pursued. The aim of the present study was to compare the antimicrobial efficacy, in vitro biocompatibility and wound healing capacity of the highly oxidized CD-100 hydrogel with the CD-25 hydrogel. Antimicrobial studies were performed against a range of clinically relevant abdominal microorganisms using the micro-broth dilution method. Biocompatibility testing using human dermal fibroblasts was assessed via a tetrazolium reduction assay (MTT) and a wound healing model. In contrast to the original DA-100 formulation, DA-25 was found to be non-cytotoxic, and showed no overall impairment of cell migration, with wound closure occurring at 72 h. However, the lower oxidation level negatively affected the antimicrobial efficacy of the hydrogel (CD-25). Although the CD-25 hydrogel's antimicrobial efficacy and anti-fibroblast activity is decreased when compared to the original CD-100 hydrogel formulation, previous in vivo studies show that the CD-25 hydrogel remains an effective, biocompatible barrier agent in the prevention of postoperative adhesions.

  19. Reducing the Oxidation Level of Dextran Aldehyde in a Chitosan/Dextran-Based Surgical Hydrogel Increases Biocompatibility and Decreases Antimicrobial Efficacy

    Directory of Open Access Journals (Sweden)

    Maggie Chan

    2015-06-01

    Full Text Available A highly oxidized form of a chitosan/dextran-based hydrogel (CD-100 containing 80% oxidized dextran aldehyde (DA-100 was developed as a post-operative aid, and found to significantly prevent adhesion formation in endoscopic sinus surgery (ESS. However, the CD-100 hydrogel showed moderate in vitro cytotoxicity to mammalian cell lines, with the DA-100 found to be the cytotoxic component. In order to extend the use of the hydrogel to abdominal surgeries, reformulation using a lower oxidized DA (DA-25 was pursued. The aim of the present study was to compare the antimicrobial efficacy, in vitro biocompatibility and wound healing capacity of the highly oxidized CD-100 hydrogel with the CD-25 hydrogel. Antimicrobial studies were performed against a range of clinically relevant abdominal microorganisms using the micro-broth dilution method. Biocompatibility testing using human dermal fibroblasts was assessed via a tetrazolium reduction assay (MTT and a wound healing model. In contrast to the original DA-100 formulation, DA-25 was found to be non-cytotoxic, and showed no overall impairment of cell migration, with wound closure occurring at 72 h. However, the lower oxidation level negatively affected the antimicrobial efficacy of the hydrogel (CD-25. Although the CD-25 hydrogel’s antimicrobial efficacy and anti-fibroblast activity is decreased when compared to the original CD-100 hydrogel formulation, previous in vivo studies show that the CD-25 hydrogel remains an effective, biocompatible barrier agent in the prevention of postoperative adhesions.

  20. Measurements of nitrite production and nitrite-producing organisms in and around the primary nitrite maximum in the central California Current

    Directory of Open Access Journals (Sweden)

    A. E. Santoro

    2013-03-01

    Full Text Available Nitrite (NO2– is a substrate for both oxidative and reductive microbial metabolism. NO2– accumulates at the base of the euphotic zone in oxygenated, stratified open ocean water columns, forming a feature known as the primary nitrite maximum (PNM. Potential pathways of NO2– production include the oxidation of ammonia (NH3 by ammonia-oxidizing bacteria or archaea and assimilatory nitrate (NO3– reduction by phytoplankton or heterotrophic bacteria. Measurements of NH3 oxidation and NO3– reduction to NO2– were conducted at two stations in the central California Current in the eastern North Pacific to determine the relative contributions of these processes to NO2– production in the PNM. Sensitive (−1, high-resolution measurements of [NH4+] and [NO2–] indicated a persistent NH4+ maximum overlying the PNM at every station, with concentrations as high as 1.5 μmol L−1. Within and just below the PNM, NH3 oxidation was the dominant NO2– producing process with rates of NH3 oxidation of up to 50 nmol L−1 d−1, coinciding with high abundances of ammonia-oxidizing archaea. Though little NO2– production from NO3– was detected, potentially nitrate-reducing phytoplankton (photosynthetic picoeukaryotes, Synechococcus, and Prochlorococcus were present at the depth of the PNM. Rates of NO2– production from NO3– were highest within the upper mixed layer (4.6 nmol L−1 d−1 but were either below detection limits or 10 times lower than NH3 oxidation rates around the PNM. One-dimensional modeling of water column NO2– profiles supported direct rate measurements of a net biological sink for NO2– just below the PNM. Residence time estimates of NO2– within the PNM were similar at the mesotrophic and oligotrophic stations and ranged from 150–205 d. Our results suggest the PNM is a dynamic, rather than relict, feature with a source term dominated by ammonia oxidation.

  1. Magnetic investigation of zero-field-cooled dextran-coated magnetite-based magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Morais, P.C. [Universidade de Brasilia, Instituto de Fisica, Fisica Aplicada, C.P. 004455, Campus Universitario, Brasilia-DF 70919 970 (Brazil)]. E-mail: pcmor@unb.br; Santos, J.G. [Universidade de Brasilia, Instituto de Fisica, Fisica Aplicada, C.P. 004455, Campus Universitario, Brasilia-DF 70919 970 (Brazil); Silveira, L.B. [Universidade de Brasilia, Instituto de Fisica, Fisica Aplicada, C.P. 004455, Campus Universitario, Brasilia-DF 70919 970 (Brazil); Nunes, W.C. [Universidade Federal doRio de Janeiro, Instituto de Fisica, 21945-970, Rio de Janeiro-RJ (Brazil); Sinnecker, J.P. [Universidade Federal doRio de Janeiro, Instituto de Fisica, 21945-970, Rio de Janeiro-RJ (Brazil); Novak, M.A. [Universidade Federal doRio de Janeiro, Instituto de Fisica, 21945-970, Rio de Janeiro-RJ (Brazil)

    2005-03-15

    In this study, we investigate the temperature dependence of the zero-field-cooled magnetization of a quasi-monodisperse dextran-coated magnetite-based magnetic fluid. The well-defined maximum in the magnetization versus temperature curve and its downshift with the applied external field is explained by a simple model considering thermally activated dynamics of the nanoparticles magnetic moment and the temperature dependence of the saturation magnetization.

  2. Preclinical and Clinical In Vitro In Vivo Correlation of an hGH Dextran Microsphere Formulation

    OpenAIRE

    2007-01-01

    Purpose To investigate the in vitro in vivo correlation of a sustained release formulation for human growth hormone (hGH) based on hydroxyethyl methacrylated dextran (dex-HEMA) microspheres in Pit-1 deficient Snell dwarf mice and in healthy human volunteers. Materials and Methods A hGH-loaded microsphere formulation was developed and tested in Snell dwarf mice (pharmacodynamic study) and in healthy human volunteers (pharmacokinetic study). Results Single subcutaneous administration of the mic...

  3. Dextran X 500. sup(99m)Tc in abdominal lymphoscintillation

    Energy Technology Data Exchange (ETDEWEB)

    Ceriani, J.; Caneda, G.; Rozados, I. (Hospital Ramos Mejia, Buenos Aires (Argentina). Div. Medicina Nuclear); Arguelles, M.G.; Canellas, C.O.; Mitta, A.E.A. (Comision Nacional de Energia Atomica, Buenos Aires (Argentina))

    1984-01-01

    The preparation of Dextran X 500 sup(99m)Tc, its control and biological behaviour in animals are described. Its use in the study of lymphatic system in human beings is also indicated. This method is of easy preparation and of great stability, both in vitro and in vivo, and besides it can be used in lymphoscintillation as well as for the study of blood pool.

  4. Fabrication and characterization of ultrathin dextran layers: Time dependent nanostructure in aqueous environments revealed by OWLS.

    Science.gov (United States)

    Saftics, Andras; Kurunczi, Sándor; Szekrényes, Zsolt; Kamarás, Katalin; Khánh, Nguyen Quoc; Sulyok, Attila; Bősze, Szilvia; Horvath, Robert

    2016-10-01

    Surface coatings of the polysaccharide dextran and its derivatives are key ingredients especially in label-free biosensors for the suppression of non-specific binding and for receptor immobilization. Nevertheless, the nanostructure of these ultrathin coatings and its tailoring by the variation of the preparation conditions have not been profoundly characterized and understood. In this work carboxymethylated dextran (CMD) was prepared and used for fabricating ultrathin surface coatings. A grafting method based on covalent coupling to aminosilane- and epoxysilane-functionalized surfaces was applied to obtain thin CMD layers. The carboxyl moiety of the CMD was coupled to the aminated surface by EDC-NHS reagents, while CMD coupling through epoxysilane molecules was performed without any additional reagents. The surface analysis following the grafting procedures consisted of X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared spectroscopy (ATR-IR), spectroscopic ellipsometry, atomic force microscopy (AFM) and optical waveguide lightmode spectroscopy (OWLS). The XPS and AFM measurements showed that the grafting resulted in a very thin dextran layer of a few nanometers. The OWLS method allowed devising the structure of the interfacial dextran layers by the evaluation of the optogeometrical parameters. The alteration in the nanostructure of the CMD layer with the chemical composition of the silane coverage and the pH of the grafting solution was revealed by in situ OWLS, specifically, lain down chains were found to be prevalent on the surface under neutral and basic conditions on epoxysilylated surfaces. The developed methodologies allowed to design and fabricate nanometer scale CMD layers with well-controlled surface structure, which are very difficult to characterize in aqueous environments using present instrumentations and highly hydrated surface layers.

  5. Safety and efficacy of iron sucrose in patients sensitive to iron dextran: North American clinical trial.

    Science.gov (United States)

    Van Wyck, D B; Cavallo, G; Spinowitz, B S; Adhikarla, R; Gagnon, S; Charytan, C; Levin, N

    2000-07-01

    Sensitivity to iron dextran is a potent obstacle to maintaining optimum iron status in patients with dialysis-associated anemia. As part of the North American clinical trials for iron sucrose injection, we examined the effect of intravenous (IV) iron sucrose in 23 hemodialysis patients with documented sensitivity to iron dextran, ongoing epoetin alfa therapy, and below-target-range hemoglobin (Hgb) levels (iron dextran were judged to be mild (n = 16; group A) or severe (n = 7; group B). We prospectively examined adverse events and vital signs after administering 100 mg of IV iron sucrose in each of 10 consecutive dialysis treatment sessions and compared results with those recorded in each of three consecutive dialysis sessions without iron treatment. We administered iron sucrose by IV push over 5 minutes to group A patients and by IV push over 5 minutes or IV infusion over 15 to 30 minutes to group B patients. We did not administer a test dose. Results showed no serious adverse drug reactions after a total of 223 doses of iron sucrose (184 doses by IV push, 39 doses by IV infusion). Intradialytic blood pressure changes after IV iron sucrose injection did not differ from those recorded during dialysis sessions without treatment. An increase in values for Hgb, hematocrit, transferrin saturation, and ferritin, coupled with no significant change in epoetin dose and a decrease in total iron-binding capacity, confirmed the efficacy of iron sucrose injection in managing anemia. We conclude that iron sucrose injection is safe and effective in the management of anemia in patients sensitive to iron dextran and can be administered without a test dose by IV push or infusion.

  6. Effects of orally administered bovine lactoperoxidase on dextran sulfate sodium-induced colitis in mice.

    Science.gov (United States)

    Shin, Kouichirou; Horigome, Ayako; Yamauchi, Koji; Takase, Mitsunori; Yaeshima, Tomoko; Iwatsuki, Keiji

    2008-07-01

    The effect of lactoperoxidase (LPO) on dextran sulfate sodium-induced colitis was examined in mice. After 9 d of colitis induction, weight loss, colon shortening, and the histological score were significantly suppressed in mice orally administered LPO (62.5 mg/body/d) as compared to a group administered bovine serum albumin. These results suggest that LPO exhibits anti-inflammatory effects in the gastrointestinal tract.

  7. Correlation between UV-VIS spectra and the structure of Cu(II complexes with hydrogenated dextran in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Nikolić Goran S.

    2005-01-01

    Full Text Available UV-VIS spectrophotometric investigations of Cu(II complexes with hydroge-nated dextran showed that the complexation of Cu(II-ions began at pH > 7. The formation of Cu(II complexes with dextran monomer units was observed at pH 7-12. With further increase in solution pH > 12, the Cu(II-dextran complex decomposed to Cu(OH42~-ions and dextran. With increasing solution pH the absorption maximum of complex solutions increased and shifted to shorter wavelength (hypsochromic shift compared with uncomplexed Cu(II. The UV spectra displayed bathochromic shifts. The changes of UV-VIS spectra with increasing in solution pH confirmed the formation of different kinds of complex species. The correlation between the results of UV-VIS spectrophotometry and the central metal ionligand coordination predicted that the copper binding within the complex depended on the pH and participation H2O molecules. Dextran complexes with Cu(II were formed by the displacement of water molecules from the coordination sphere of copper by OH groups. The analysis indicated that the Cu(II center was coordinated to two glucopyranose units of dextran. The spectrophotometric parameters of the investigated complexes were characteristic of a Cu(II-ion in a square-planar or tetragon ally distorted octahedral coordination.

  8. The use of atmospheric pressure plasma-treated water as a source of nitrite for emulsion-type sausage.

    Science.gov (United States)

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; In Yong, Hae; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

    2015-10-01

    We investigated the possible use of atmospheric pressure plasma-treated water (PTW) as a nitrite source in curing process. Emulsion-type sausages were manufactured with PTW, celery powder containing nitrite, and synthetic sodium nitrite at a concentration of nitrite ion 70mgkg(-1). In terms of sausage quality, there were no noticeable effects of PTW on the total aerobic bacterial counts, color, and peroxide values of sausages compared with those of celery powder and sodium nitrite throughout 28days of storage at 4°C. Sausage with added PTW had lower concentrations of residual nitrite compared to those of added celery powder and sodium nitrite during the storage period (Psausages were not different, whereas the sausage with added celery powder received the lowest scores in taste and acceptability. From the results, it is concluded that PTW can be used as a nitrite source equivalent to a natural curing agent.

  9. Effect of sodium ascorbate and sodium nitrite on protein and lipid oxidation in dry fermented sausages.

    Science.gov (United States)

    Berardo, A; De Maere, H; Stavropoulou, D A; Rysman, T; Leroy, F; De Smet, S

    2016-11-01

    The effects of sodium nitrite and ascorbate on lipid and protein oxidation were studied during the ripening process of dry fermented sausages. Samples were taken at day 0, 2, 8, 14, 21 and 28 of ripening to assess lipid (malondialdehyde) and protein (carbonyls and sulfhydryl groups) oxidation. Sodium ascorbate and nitrite were separately able to reduce the formation of malondialdehyde. Their combined addition resulted in higher amounts of carbonyl compounds compared to their separate addition or the treatment without any of both compounds. Moreover, sodium nitrite limited the formation of γ-glutamic semialdehyde whereas sodium ascorbate showed a pro-oxidant effect. A loss of thiol groups was observed during ripening, which was not affected by the use of sodium ascorbate nor sodium nitrite. In conclusion, sodium nitrite and ascorbate affected protein and lipid oxidation in different manners. The possible pro-oxidant effect of their combined addition on carbonyl formation might influence the technological and sensory properties of these products.

  10. Effect of anaerobic digestion on the high rate of nitritation, treating piggery wastewater

    Institute of Scientific and Technical Information of China (English)

    Jiyeol Im; Kyungik Gil

    2011-01-01

    The amount of piggery wastewater as domestic livestock is increasing.The volume of piggery wastewater produced is less than the volume of other wastewaters,but piggery wastewater has a heavy impact on wastewater streams due to an extremely high concentration of nitrogen and COD.In this study,laboratory reactors were operated using piggery wastewater and the effluent of anaerobic digester from piggery wastewater plants.The purpose of this study was to induce the nitritation process,which is an economically advantageous nitrogen removal method that converts ammonium nitrogen into nitrite.The results showed that the effluent of anaerobic digester from piggery wastewater was more efficient than raw piggery wastewater in terms of inducing nitritation.It can be deduced that nitritation is largely affected by an organic fraction of piggery wastewater.It can also be concluded that a small amount of biodegradable organic matter in piggery wastewater is efficient in inducing nitritation.

  11. Electrochemical Single‐Molecule AFM of the Redox Metalloenzyme Copper Nitrite Reductase in Action

    DEFF Research Database (Denmark)

    Hao, Xian; Zhang, Jingdong; Christensen, Hans Erik Mølager

    2012-01-01

    We studied the electrochemical behavior of the redox metalloenzyme copper nitrite reductase (CNiR, Achromobacter xylosoxidans) immobilized on a Au(111)‐electrode surface modified by a self‐assembled cysteamine molecular monolayer (SAM) using a combination of cyclic voltammetry and electrochemically......‐controlled atomic force microscopy (in situ AFM). The enzyme showed no voltammetric signals in the absence of nitrite substrate, whereas a strong reductive electrocatalytic signal appeared in the presence of nitrite. Such a pattern is common in protein film and monolayer voltammetry and points to conformational...... in the presence of nitrite. No change in size was observed in the absence of nitrite over the same potential range. The enzyme size variation is suggested to offer clues to the broadly observed substrate triggering in metalloenzyme monolayer voltammetry....

  12. Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters.

    Science.gov (United States)

    Bristow, Laura A; Dalsgaard, Tage; Tiano, Laura; Mills, Daniel B; Bertagnolli, Anthony D; Wright, Jody J; Hallam, Steven J; Ulloa, Osvaldo; Canfield, Donald E; Revsbech, Niels Peter; Thamdrup, Bo

    2016-09-20

    A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O2) sensitivity of these processes down to the O2 concentrations present in the OMZ core (Michaelis-Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss.

  13. Differential inhibition of polymorphonuclear leukocyte recruitment in vivo by dextran sulphate and fucoidan

    Directory of Open Access Journals (Sweden)

    N. Van Osselaer

    1996-01-01

    Full Text Available The selectin-mediated rolling of leukocytes along the endothelial cells is a prerequisite step followed by firm adhesion and extravasation into the inflamed tissue. This initial contact can be suppressed by sulphated polysaccharides. We have studied the effect of sulphated polysaccharides on the ultimate polymorphonuclear leukocyte (PMN recruitment and plasma leakage in rabbit skin in response to intradermal injection of various inflammatory mediators. PMN infiltration evoked by various PMN chemoattractants (FMLP, C5a desArg, LTB4 and IL-8 was significantly inhibited after intravenous injection of dextran sulphate (25 mg/kg, heparin (2 × 90 mg/kg or fucoidan (1 mg/kg. PMN-dependent plasma leakage was equally well reduced by the different sulphated polymers. Vascular permeability induced by histamine or thrombin acting via a PMN-independent mechanism was not reduced. Fucoidan was the only polysaccharide able to suppress IL-1-induced PMN infiltration for 60–70%. Local administration of dextran sulphate had no effect on PMN-dependent plasma leakage. Differential inhibition of PMN recruitment was determined after injection of dextran sulphate or fucoidan depending on the type of insult. Therefore, these results suggest that different adhesion pathways are utilized during PMN recruitment in vivo in response to chemoattractants and IL-1.

  14. Magnetic retardance and magnetic heating in dextran-citrate coated ferrofluids

    Directory of Open Access Journals (Sweden)

    Jing-Fung Lin

    2017-02-01

    Full Text Available The Fe3O4 magnetic nanoparticles (MNPs coated by citrate and dextran prepared by the co-precipitation method was described. Influence induced by the mass variation of coating dextran was investigated. Magneto-optical birefringence of biocompatible dextran-citrate (DC coated ferrofluids (FFs was obtained by the Stokes polarimeter. Next, uniform design method was used to find the DC coated FF with high retardance and low dichroism. Retardance of the optimized A9 sample with 1 g/ml was measured as 56.7898° (dichroism was 0.3716 under 64.5 mT. Further, magnetic heating effect in alternating magnetic field was investigated. When the concentrations of A9 were of 2 mg/ml and 50 mg/ml, under the external alternating magnetic field with applied apparent current of 210 A, after heating 5 s the temperature of the DC coated FFs was greater than 47 °C, respectively, reached the requirements for the magnetic inductive heating treatment of cancer tumor. The potential of DC coated FFs in hyperthermia was highly evaluated.

  15. Hybridization chain reaction amplification for highly sensitive fluorescence detection of DNA with dextran coated microarrays.

    Science.gov (United States)

    Chao, Jie; Li, Zhenhua; Li, Jing; Peng, Hongzhen; Su, Shao; Li, Qian; Zhu, Changfeng; Zuo, Xiaolei; Song, Shiping; Wang, Lianhui; Wang, Lihua

    2016-07-15

    Microarrays of biomolecules hold great promise in the fields of genomics, proteomics, and clinical assays on account of their remarkably parallel and high-throughput assay capability. However, the fluorescence detection used in most conventional DNA microarrays is still limited by sensitivity. In this study, we have demonstrated a novel universal and highly sensitive platform for fluorescent detection of sequence specific DNA at the femtomolar level by combining dextran-coated microarrays with hybridization chain reaction (HCR) signal amplification. Three-dimensional dextran matrix was covalently coated on glass surface as the scaffold to immobilize DNA recognition probes to increase the surface binding capacity and accessibility. DNA nanowire tentacles were formed on the matrix surface for efficient signal amplification by capturing multiple fluorescent molecules in a highly ordered way. By quantifying microscopic fluorescent signals, the synergetic effects of dextran and HCR greatly improved sensitivity of DNA microarrays, with a detection limit of 10fM (1×10(5) molecules). This detection assay could recognize one-base mismatch with fluorescence signals dropped down to ~20%. This cost-effective microarray platform also worked well with samples in serum and thus shows great potential for clinical diagnosis.

  16. DNA replication by a possible continuous--discontinuous mechanism in homogenates of Physarum polycephalum containing dextran

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, E.N.

    1975-01-01

    Nuclear DNA synthesis in homogenates of Physarum is greatly stimulated by the presence of dextran in the homogenizing medium. In this cell-free system, the DNA precursor is incorporated approximately equally into two classes of DNA intermediates. One of these is similar in size to that observed previously in the intact organism, i.e., its sedimentation rate in alkaline sucrose density gradients increases, presumably by chain elongation, as the organism progresses through the S phase. The other class (approx. 10S) is similar to ''Okazaki'' fragments. Thus, nuclear DNA synthesis in homogenates of Physarum may occur by a continuous-discontinuous mechanism. Substantial DNA-synthetic activity is obtained by the addition of dextran to dextran-free homogenates. Maximal activity in this system requires the presence of both the nuclear and post-nuclear supernatant fractions. It is possible that a partial separation and recombination of a DNA polymerase and the endogenous template is effected by this procedure. (auth)

  17. Prevent Effects of Lactobacillus Fermentum HY01 on Dextran Sulfate Sodium-Induced Colitis in Mice

    Science.gov (United States)

    Chen, Xiaoyong; Zhao, Xin; Wang, Hongwei; Yang, Zelin; Li, Jian; Suo, Huayi

    2017-01-01

    The aim of this study is to assess the preventive effects of Lactobacillus fermentum HY01 (LF-HY01) to dextran sulfate sodium induced-colitis. We observed the ratio of colon weight to its length, colon pathological changes, and the concentrations of pro-inflammatory factors (IFN-γ, IL-12, TNFα, and IL-6) in serum. We also took account of the protein levels of IκBα, NF-κB p65, iNOS, and COX-2, and we measured the best effects of different doses of Lactobacillus fermentum HY01 (low dose group was 109 CFU/kg·bw, high dose group was 1010 CFU/kg·bw) on dextran sulfate sodium-induced colitis mice. The results were remarkable, suggesting that Lactobacillus fermentum HY01 had significant preventive effects in dextran sulfate sodium induced-colitis; simultaneously, the high dose group showed the best results among other groups. It can effectively alleviate the shortened colon length, reduce the ratio of colon weight to its length, reduce edema, inflammatory cells infiltration, and colon mucosa injury, and play an important role in the down-regulation of concentrations of pro-inflammatory factors (IFN-γ, IL-12, TNFα, and IL-6). Above all, Lactobacillus fermentum HY01 shows promising prevention for IκBα degradation, inhibition of NF-κB p65 phosphorylation cascades, and decreases the protein levels of iNOS and COX-2 as well. PMID:28587089

  18. Dextran-coated superparamagnetic amorphous Fe–Co nanoalloy for magnetic resonance imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    An, Lu; Yu, Yanrong; Li, Xuejian; Liu, Wei [The Key Laboratory of Resource Chemistry of Ministry of Education and Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Yang, Hong, E-mail: yanghong@shnu.edu.cn [The Key Laboratory of Resource Chemistry of Ministry of Education and Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Wu, Dongmei [Shanghai Key Laboratory of Magnetic Resonance, Department of Physics, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Yang, Shiping, E-mail: shipingy@shnu.edu.cn [The Key Laboratory of Resource Chemistry of Ministry of Education and Shanghai Key Laboratory of Rare Earth Functional Materials, Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2014-01-01

    Graphical abstract: A dextran-coated Fe–Co nanoalloy was developed serving as a sensitive contrast agent for magnetic resonance imaging applications. - Highlights: • Amorphous Fe–Co nanoalloy was prepared via wet chemical reduction approach. • The Fe–Co nanoalloy is water-soluble, stable, and biocompatible. • The Fe–Co nanoalloy is superparamagnetic. • The Fe–Co nanoalloy exhibits T{sub 2}-weighted MR enhancement both in vitro and in vivo. - Abstract: For magnetic resonance imaging applications, a facile approach for water-soluble dextran coated amorphous Fe–Co nanoalloy was developed. The as-synthesized nanoalloy had a diameter of 9 nm with a narrow size distribution and showed superparamagnetic property with a saturated magnetization (Ms) of 25 emu/g. In vitro cytotoxicity test revealed that it was biocompatible at a concentration below 120 μg/mL. It can be uptaken by HeLa cells effectively and resulted in the obvious T{sub 2} effect after internalization. Biodistribution studies in conjunction with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) confirmed that Fe–Co nanoalloy was preferentially accumulated in lung and spleen after intravenous injection for 4 h. In vivo MRI, dextran-coated Fe–Co nanoalloy can serve as a sensitive contrast agent for MR imaging, especially in the spleen, so we believe that it maybe hold great promise for diagnosis of splenic disease by appropriately functionalizing their surface.

  19. Highly Selective Photothermal Therapy by a Phenoxylated-Dextran-Functionalized Smart Carbon Nanotube Platform.

    Science.gov (United States)

    Han, Seungmin; Kwon, Taeyun; Um, Jo-Eun; Haam, Seungjoo; Kim, Woo-Jae

    2016-05-01

    Near-infrared (NIR) photothermal therapy using biocompatible single-walled carbon nanotubes (SWNTs) is advantageous because as-produced SWNTs, without additional size control, both efficiently absorb NIR light and demonstrate high photothermal conversion efficiency. In addition, covalent attachment of receptor molecules to SWNTs can be used to specifically target infected cells. However, this technique interrupts SWNT optical properties and inevitably lowers photothermal conversion efficiency and thus remains major hurdle for SWNT applications. This paper presents a smart-targeting photothermal therapy platform for inflammatory disease using newly developed phenoxylated-dextran-functionalized SWNTs. Phenoxylated dextran is biocompatible and efficiently suspends SWNTs by noncovalent π-π stacking, thereby minimizing SWNT bundle formations and maintaining original SWNT optical properties. Furthermore, it selectively targets inflammatory macrophages by scavenger-receptor binding without any additional receptor molecules; therefore, its preparation is a simple one-step process. Herein, it is experimentally demonstrated that phenoxylated dextran-SWNTs (pD-SWNTs) are also biocompatible, selectively penetrate inflammatory macrophages over normal cells, and exhibit high photothermal conversion efficiency. Consequently, NIR laser-triggered macrophage treatment can be achieved with high accuracy by pD-SWNT without damaging receptor-free cells. These smart targeting materials can be a novel photothermal agent candidate for inflammatory disease.

  20. Magnetic field dependence of the diffusion of single dextran molecules within a hydrogel containing magnetite nanoparticles.

    Science.gov (United States)

    Al-Baradi, Ateyyah M; Mykhaylyk, Oleksandr O; Blythe, Harry J; Geoghegan, Mark

    2011-03-07

    We consider the effect of applied magnetic fields on the diffusion of single dextran molecules labeled with fluorescein isothiocyanate within a ferrogel [a composite of magnetite nanoparticles in a poly(methacrylic acid) hydrogel] using fluorescence correlation spectroscopy. We show that the mesh size of the ferrogel is controlled by the applied magnetic field, B, and scales as exp(-(4)√ξ(3)B(2)/2μ(0)k(B)T), where ξ is a correlation length, μ(0) the magnetic constant, k(B) the Boltzmann constant, and T is the absolute temperature. The diffusion coefficient of the dextran can be modeled with a simple Stokes-Einstein law, containing the same scaling behavior with magnetic field as the swelling of the hydrogel. Furthermore, the magnetic field-dependent release of dextran from the hydrogel is also controlled by the same relationship. The samples were characterized by small angle x-ray scattering (SAXS) and magnetometry experiments. Magnetic hysteresis loops from these ferrogels and zero field cooled∕field cooled measurements reveal single domain ferromagnetic behavior at room temperature with a similar coercivity for both as-prepared and fully swollen ferrogels, and for increasing magnetic nanoparticle concentration. SAXS experiments, such as the hysteresis loops, show that magnetite does not aggregate in these gels.

  1. New shell crosslinked micelles from dextran with hydrophobic end groups and their interaction with bioactive molecules.

    Science.gov (United States)

    Mocanu, Georgeta; Nichifor, Marieta; Stanciu, Magdalena C

    2015-03-30

    Micelles formed in aqueous solution by dextran with hydrophobic (alkyl) end-groups were stabilized through divinyl sulfone crosslinking of the dextran shell. The efficacy of the crosslinking reaction was influenced by the divinyl sulfone amount, the pH and micelle concentration. Crosslinked micelles with a moderate crosslinking degree were further functionalized by attachment of 10 and 17 moles% N-(2-hydroxypropyl)-N,N-dimethyl-N-benzylammonium chloride groups along the dextran chain. The size and shape of both crosslinked micelles and their cationic derivatives were analyzed by DLS and TEM. The prepared micelles were able to bind anionic diclofenac (60-370 mg/g), hydrophobic anionic indometacin (70-120 mg/g), and hydrophobic alpha-tocopherol (170-220 mg/g) or ergocalciferol (90-110 mg/g) by hydrophobic or/and electrostatic forces. The release experiments and the antioxidant activity of bound alpha-tocopherol highlighted the potential of the new nano-sized micelles mainly as carriers for prolonged and controlled delivery of hydrophobic drugs.

  2. [Indirect articular lymphography using Tc 99m-labeled Dextran in animals].

    Science.gov (United States)

    Albuquerque, M; Pedroso de Lima, J; Cardoso, A; Mendes, F; Pires, J; Canha, N; Branco, R

    1990-01-01

    Looking for a standardization of the articular lymphoscintigraphy, an experimental research was conducted on 14 dogs injected in the ankle, with 2.5 mCi of 99m Tc-labeled dextran (P.M. = 70,000). Good scintigraphic images of the lymphatic system have been obtained. After having collected blood samples during the experimentation as well as aliquots of organs and of tissues, after the necropsy of the animal, it was verified that the 99m Tc-labeled dextran was useful for quantitative studies of the articular lymphatic drainage. The activities attained, in the drainage lymph nodes of injected articulation, are 152 times superior to those obtained in the kidney and one gramma of popliteal ganglion was 8929 times more active than one gramma of blood. The dextran 70,000, widely used in our clinical routine, can be injected to the human being, without any risk, and it may be the tracer which permits studies of the articular lymphatic drainage and the usage of the lymphoscintigraphy, already in expansion in many other Medicine branches, in the articular studies, nowadays.

  3. Topical application of glycyrrhizin preparation ameliorates experimentally induced colitis in rats

    Institute of Scientific and Technical Information of China (English)

    Tomohiro Kudo; Shinichi Okamura; Yajing Zhang; Takashige Masuo; Masatomo Mori

    2011-01-01

    AIM: To examine the efficacy of glycyrrhizin preparation (GL-p) in the treatment of a rat model of ulcerative colitis (UC). METHODS: Experimental colitis was induced by oral administration of dextran sodium sulfate. Rats with colitis were intrarectally administered GL-p or saline. The extent of colitis was evaluated based on body weight gain,colon wet weight,and macroscopic damage score. The expression levels of pro-inflammatory cytokines and chemokines in the inflamed mucosa were measured by cytokine antibody array analysis. The effect of GL-p on myeloperoxidase (MPO) activity in the inflamed mucosa and purified enzyme was assayed. RESULTS: GL-p treatment significantly ameliorated the extent of colitis compared to sham treatment with saline. Cytokine antibody array analysis showed that GL-p treatment significantly decreased the expression levels of pro-inflammatory cytokines and chemokines,including interleukin (IL)-1β,IL-6,tumor necrosis factor-α,cytokine-induced neutrophil chemoattractant-2,and monocyte chemoattractant protein-1 in the inflamed mucosa. Furthermore,GL-p inhibited the oxidative activity of mucosal and purified MPO. CONCLUSION: GL-p enema has a therapeutic effect on experimental colitis in rats and may be useful in the treatment of UC.

  4. Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

    Science.gov (United States)

    Totzeck, Matthias; Hendgen-Cotta, Ulrike B; Kelm, Malte; Rassaf, Tienush

    2014-01-01

    The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

  5. Antimicrobial effect of acidified nitrate and nitrite on six common oral pathogens in vitro

    Institute of Scientific and Technical Information of China (English)

    XIA Deng-sheng; LIU Yin; ZHANG Chun-mei; YANG Sheng-hui; WANG Song-lin

    2006-01-01

    Background Salivary nitrate is positively correlated with plasma nitrate and its level is 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3-5 times those in serum in physiological conditions respectively in our previous study. The biological functions of high salivary nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions.Methods Six common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid medium. Sodium nitrate or sodium nitrite was added to the medium to final concentrations of 0, 0.5, 1, 2, and 10 mmol/L. All of the microorganisms were incubated for 24 to 48 hours. The optical densities (OD) of cell suspensions were determined and the cultures were transferred to solid nutrient broth medium to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens.Results Nitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens.Conclusion Nitrite, at a concentration equal to that in human saliva, is both cytocidal and cytostatic to six principal oral pathogens in vitro, whereas nitrate at a similar

  6. Estimation of nitrite in source-separated nitrified urine with UV spectrophotometry.

    Science.gov (United States)

    Mašić, Alma; Santos, Ana T L; Etter, Bastian; Udert, Kai M; Villez, Kris

    2015-11-15

    Monitoring of nitrite is essential for an immediate response and prevention of irreversible failure of decentralized biological urine nitrification reactors. Although a few sensors are available for nitrite measurement, none of them are suitable for applications in which both nitrite and nitrate are present in very high concentrations. Such is the case in collected source-separated urine, stabilized by nitrification for long-term storage. Ultraviolet (UV) spectrophotometry in combination with chemometrics is a promising option for monitoring of nitrite. In this study, an immersible in situ UV sensor is investigated for the first time so to establish a relationship between UV absorbance spectra and nitrite concentrations in nitrified urine. The study focuses on the effects of suspended particles and saturation on the absorbance spectra and the chemometric model performance. Detailed analysis indicates that suspended particles in nitrified urine have a negligible effect on nitrite estimation, concluding that sample filtration is not necessary as pretreatment. In contrast, saturation due to very high concentrations affects the model performance severely, suggesting dilution as an essential sample preparation step. However, this can also be mitigated by simple removal of the saturated, lower end of the UV absorbance spectra, and extraction of information from the secondary, weaker nitrite absorbance peak. This approach allows for estimation of nitrite with a simple chemometric model and without sample dilution. These results are promising for a practical application of the UV sensor as an in situ nitrite measurement in a urine nitrification reactor given the exceptional quality of the nitrite estimates in comparison to previous studies.

  7. Characterization of nitrite degradation by Lactobacillus casei subsp. rhamnosus LCR 6013.

    Directory of Open Access Journals (Sweden)

    Dong-mei Liu

    Full Text Available Nitrites are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. The nitrite degradation capacity of Lactobacillus casei subsp. rhamnosus LCR 6013 was investigated in pickle fermentation. After LCR 6013 fermentation for 120 h at 37°C, the nitrite concentration in the fermentation system was significantly lower than that in the control sample without the LCR 6013 strain. The effects of NaCl and Vc on nitrite degradation by LCR 6013 in the De Man, Rogosa and Sharpe (MRS medium were also investigated. The highest nitrite degradations, 9.29 mg/L and 9.89 mg/L, were observed when NaCl and Vc concentrations were 0.75% and 0.02%, respectively in the MRS medium, which was significantly higher than the control group (p ≤ 0.01. Electron capture/gas chromatography and indophenol blue staining were used to study the nitrite degradation pathway of LCR 6013. The nitrite degradation products contained N2O, but no NH4(+. The LCR 6013 strain completely degraded all NaNO2 (50.00 mg/L after 16 h of fermentation. The enzyme activity of NiR in the periplasmic space was 2.5 times of that in the cytoplasm. Our results demonstrated that L. casei subsp. rhamnosus LCR 6013 can effectively degrade nitrites in both the pickle fermentation system and in MRS medium by NiR. Nitrites are degraded by the LCR 6013 strain, likely via the nitrate respiration pathway (NO2(->NO->N2O->N2, rather than the aammonium formation pathway (dissimilatory nitrate reduction to ammonium, DNRA, because the degradation products contain N2O, but not NH4(+.

  8. Intake assessment of the food additives nitrite (E 249 and E 250) and nitrate (E 251 and E 252)

    NARCIS (Netherlands)

    Sprong RC; Niekerk EM; Beukers MH; VVH; V&Z

    2017-01-01

    Nitrate and nitrite are authorised as preservatives in certain food products, such as salami, ham (nitrite) and cheese (nitrate). They prevent food spoilage and protect the consumer against food-borne pathogens. Next to that, nitrate and nitrite play a role in food colour retention and contribute to

  9. 78 FR 69646 - Sodium Nitrite From the People's Republic of China: Final Results of the Expedited First Sunset...

    Science.gov (United States)

    2013-11-20

    ... International Trade Administration Sodium Nitrite From the People's Republic of China: Final Results of the... countervailing duty (``CVD'') order on sodium nitrite from the People's Republic of China (``PRC'') would be... sodium nitrite from the PRC, pursuant to section 751(c) of the Tariff Act of 1930, as amended (``the...

  10. 78 FR 69368 - Sodium Nitrite From Germany and the People's Republic of China: Final Results of the Expedited...

    Science.gov (United States)

    2013-11-19

    ... International Trade Administration Sodium Nitrite From Germany and the People's Republic of China: Final Results... reviews of the antidumping duty (``AD'') orders on sodium nitrite from Germany and the People's Republic... nitrite from Germany and the PRC.\\1\\ On July 1, 2013, the Department published the notice of initiation...

  11. 78 FR 68474 - Sodium Nitrite From China And Germany; Scheduling of Expedited Five-Year Reviews Concerning the...

    Science.gov (United States)

    2013-11-14

    ... COMMISSION Sodium Nitrite From China And Germany; Scheduling of Expedited Five-Year Reviews Concerning the... on Sodium Nitrite From Germany AGENCY: United States International Trade Commission. ACTION: Notice... duty order on sodium nitrite from Germany would be likely to lead to continuation or recurrence...

  12. Fluorescence tomographic imaging of sentinel lymph node using near-infrared emitting bioreducible dextran nanogels

    Directory of Open Access Journals (Sweden)

    Li J

    2014-12-01

    Full Text Available Jiejing Li,1* Beiqi Jiang,1* Chao Lin,2 Zhigang Zhuang1 1Department of Breast Surgery, Shanghai First Maternity and Infant Hospital, 2The Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Tongji University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Sentinel lymph node (SLN mapping is a critical procedure for SLN biopsy and its diagnosis as tumor metastasis in clinical practice. However, SLN mapping agents used in the clinic frequently cause side effects and complications in the patients. Here, we report the development of a near-infrared (NIR emitting polymeric nanogel with hydrodynamic diameter of ~28 nm – which is the optimal size for SLN uptake – for noninvasive fluorescence mapping of SLN in a mouse. This polymeric nanogel was obtained by coupling Cy7, an NIR dye, to the self-assembled nanogel from disulfide-linked dextran-deoxycholic acid conjugate with the dextran of 10 kDa, denoted as Dex–Cy7. Fluorescence imaging analysis showed that Dex–Cy7 nanogels had an enhanced photostability when compared to Cy7 alone. After intradermal injection of Dex–Cy7 nanogel into the front paw of a mouse, the nanogels were able to migrate into the mouse’s axillary lymph node, exhibiting longer retention time and higher fluorescence intensity in the node when compared to Cy7 alone. An immunohistofluorescence assay revealed that the nanogels were localized in the central region of lymph node and that the uptake was largely by the macrophages. In vitro and in vivo toxicity results indicated that the dextran-based nanogels were of low cytotoxicity at a polymer concentration up to 1,000 µg/mL and harmless to normal liver and kidney organs in mice at an intravenous dose of 1.25 mg/kg. The results of this study suggest that NIR-emitting polymeric nanogels based on bioreducible dextran-deoxycholic acid conjugates show high potential as fluorescence

  13. Nitrite attenuated hypochlorous acid-mediated heme degradation in hemoglobin.

    Science.gov (United States)

    Lu, Naihao; Li, Jiayu; Ren, Xiaoming; Tian, Rong; Peng, Yi-Yuan

    2015-08-05

    Hypochlorous acid (HOCl) is elevated in many inflammatory diseases and causes the accumulation of free iron. Through the Fenton reaction, free iron has the ability to generate free radicals and subsequently is toxic. Recent studies have demonstrated that HOCl participates in heme destruction of hemoglobin (Hb) and free iron release. In this study, it was showed that nitrite (NO2(-)) could prevent HOCl-mediated Hb heme destruction and free iron release. Also, NO2(-) prevented HOCl-mediated loss of Hb peroxidase activity. After the NO2(-)/HOCl treatment, Tyr 42 in α-chain was found to be nitrated in Hb, attenuating the electron transferring abilities of phenolic compounds. The protective effects of NO2(-) on HOCl-induced heme destruction were attributed to its reduction of ferryl Hb and/or direct scavenging of HOCl. Therefore, NO2(-) could show protective effects in some inflammatory diseases by preventing HOCl-mediated heme destruction of hemoproteins and free iron release.

  14. Addition of nitrite enhances the electrochemical defluorination of 2-fluoroaniline

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Huajun [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China); Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012 (China); Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Liang, Yuxiang [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China); Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012 (China); Guo, Kun [Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Long, Yuyang [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China); Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012 (China); Cong, Yanqing, E-mail: yqcong@hotmail.com [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China); Shen, Dongsheng [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China); Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012 (China)

    2015-12-30

    Highlights: • A method for improving defluorination performance by in situ self-assembly of pollutants was developed. • The mechanisms of 2-FA modification and defluorination are discussed. • Positively-charged diazonium salt is used to weaken the C–F bond. - Abstract: This study introduces a novel approach that uses the interaction of pollutants with added nitrite to produce diazonium salts, which cause in situ self-assembly of the pollutants on carbon electrodes, to improve their 2-fluoroaniline (2-FA) defluorination and removal performance. The 2-FA degradation performance, electrode properties, electrochemical properties and degradation pathway were investigated. The reactor containing NO{sub 2}{sup −} achieved a 2-FA removal efficiency of 90.1% and a defluorination efficiency of 38% within 48 h, 1.4 and 2.3 times higher than the corresponding results achieved without NO{sub 2}{sup −}, respectively. The residual NO{sub 2}{sup −} was less than 0.5 mg/L in the reactor containing added NO{sub 2}{sup −}, which would not cause serious secondary pollution. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results proved that the carbon anode surface was successfully modified with benzene polymer, and electrochemical tests confirmed that the electrochemical activity of the modified anode was enhanced significantly. The C–F bond was weakened by the effect of the positive charge of the benzenediazonium groups, and the high electrochemical activity of the carbon anode enhanced the electrochemical performance of the system to accelerate defluorination. Thus, the present electrical method involving nitrite nitrogen is very promising for the treatment of wastewater containing fluoroaniline compounds.

  15. Internalization of Staphylococcus aureus in Lymphocytes Induces Oxidative Stress and DNA Fragmentation: Possible Ameliorative Role of Nanoconjugated Vancomycin

    Directory of Open Access Journals (Sweden)

    Subhankari Prasad Chakraborty

    2011-01-01

    Full Text Available Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA and vancomycin-resistant Staphylococcus aureus (VRSA infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5×106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.

  16. Erratum to ;Coastal water column ammonium and nitrite oxidation are decoupled in summer;

    Science.gov (United States)

    Heiss, Elise M.; Fulweiler, Robinson W.

    2017-07-01

    Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen, light, and temperature. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with temperature, light and pH. Multivariate regression analysis revealed that surface (20 m) rates were regulated by temperature, light, and [H+] (i.e. pH). In addition, surface (oxygen all played a role in predicting deep (>20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

  17. Seasonal Cycle Analysis of the Nitrate Nitrogen and Nitrite Nitrogen in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    Shi Qiang; Chen Jianglin; Li Chongde

    2002-01-01

    During 1985~1987, the concentration of nitrate nitrogen was higher in the Laizhou Bay and the Bohai Bay while that of nitrite nitrogen was higher in the Liaodong Bay and the Bohai Bay. The concentration of nitrate nitrogen was highest in winter and lowest in summer while that of nitrite nitrogen was highest in autumn and lowest in spring. The seasonal variation of the concentration of nitrate nitrogen was maximum in the Laizhou Bay and the Bohai Bay while that of the concentration of nitrite nitrogen was maximum in the Liaodong Bay. There was a great difference in the concentration of nitrate nitrogen between the surface and the bottom in autumn and in the concentration of nitrite nitrogen between the surface and the bottom in summer. The main reason for the seasonal variations of the concentration of nitrate nitrogen and nitrite nitrogen was the marine biochemical process. The nitrate nitrogen and nitrite nitrogen in the Bohai Sea basically maintained a quasi-equilibrium state seasonal cycle. The quasi-equilibrium state seasonal cycle of nitrate nitrogen and nitrite nitrogen at the bottom was stable while that at the surface was liable to variations caused by other factors.

  18. Inhibition of nitrite-induced toxicity in channel catfish by calcium chloride and sodium chloride

    Science.gov (United States)

    Tommasso J.R., Wright; Simco, B.A.; Davis, K.B.

    1980-01-01

    Environmental chloride has been shown to inhibit methemoglobin formation in fish, thereby offering a protective effect against nitrite toxicity. Channel catfish (Ictalurus punctatus) were simultaneously exposed to various environmental nitrite and chloride levels (as either CaCl2 or NaCl) in dechlorinated tap water (40 mg/L total hardness, 47 mg/L alkalinity, 4 mg/L chloride, pH = 6.9-7.1, and temperature 21-24°C). Methemoglobin levels in fish simultaneously exposed to 2.5 mg/L nitrite and up to 30 mg/L chloride as either CaCl2 or NaCl were similar but significantly lower than in unprotected fish. Exposure to 10 mg/L nitrite and 60 mg/L chloride resulted in methemoglobin levels similar to those of the controls; most unprotected fish died. Fish exposed to 10 mg/L nitrite had significantly lower methemoglobin levels when protected with 15.0 mg/L chloride as CaCl2 than with NaCl. Fish exposed to nitrite in the presence of 60 mg/L chloride (as either CaCl2 or NaCl) had similar 24-h LC50 values that were significantly elevated above those obtained in the absence of chloride. Calcium had little effect on tolerance to nitrite toxicity in channel catfish in contrast to its large effect reported in steelhead trout (Salmo gairdneri).

  19. Coastal water column ammonium and nitrite oxidation are decoupled in summer

    Science.gov (United States)

    Heiss, Elise M.; Fulweiler, Robinson W.

    2016-09-01

    Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen and light. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with light and pH. Multivariate regression analysis revealed that while both surface (20 m) ammonium oxidation rates were most strongly predicted by depth and light, surface rates were also regulated by salinity and deep rates by temperature. Surface (20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

  20. The protective potential of Yucca schidigera (Sarsaponin 30) against nitrite-induced oxidative stress in rats.

    Science.gov (United States)

    Cigerci, I Hakki; Fidan, A Fatih; Konuk, Muhsin; Yuksel, Hayati; Kucukkurt, Ismail; Eryavuz, Abdullah; Sozbilir, Nalan Baysu

    2009-07-01

    The present study was designed to determine the protective effects of Yucca schidigera (Ys) against oxidative damage induced by acute nitrite intoxication as well as the histopathological evaluation of Ys in rats. The rats were divided into three groups each containing 12 rats: control (C); nitrite intoxication (N); Ys + nitrite intoxication (NY). C and N groups were fed standard rat feed (SRF). The NY group was fed SRF + 100 ppm Ys powder for 4 weeks. Acute nitrite intoxication was induced by subcutaneous (s.c.) administration of sodium nitrite (60 mg/kg) 1 day after the feeding period. Fifty minutes after sodium nitrite administration, blood samples and tissues including lung, liver, and kidney were collected for clinical biochemistry and histopathological investigations. Ys treatment was found to decrease methemoglobin, blood and tissue malondialdehyde, and tissue nitric oxide concentrations, and to increase the glutathione in blood and various tissues. However, plasma nitric oxide, total antioxidant activity, beta-carotene, and vitamin A did not differ between N and NY groups. While the N group rats showed distinct pathology in various tissues (compared with controls), the NY group had similar lung and liver pathology to the control. Only moderate or mild hemorrhage and hyperemia were seen in kidneys of NY group rats. Consequently, the natural compounds found in Ys, such as polyphenols, steroidal saponins, and other phytonutrients, could be used to substantially protect the organism from nitrite-induced oxidative damage and its complications.

  1. Phospatidylserine or ganglioside--which of anionic lipids determines the effect of cationic dextran on lipid membrane?

    Science.gov (United States)

    Hąc-Wydro, Katarzyna; Wydro, Paweł; Cetnar, Andrzej; Włodarczyk, Grzegorz

    2015-02-01

    In this work the influence of cationic polymer, namely diethylaminoethyl DEAE-dextran on model lipid membranes was investigated. This polymer is of a wide application as a biomaterial and a drug carrier and its cytotoxicity toward various cancer cells was also confirmed. It was suggested that anticancer effect of cationic dextran is connected with the binding of the polymer to the negatively charged sialic acid residues overexpressed in cancer membrane. This fact encouraged us to perform the studies aimed at verifying whether the effect of cationic DEAE-dextran on membrane is determined only by the presence of the negatively charged lipid in the system or the kind of anionic lipid is also important. To reach this goal systematic investigations on the effect of dextran on various one-component lipid monolayers and multicomponent hepatoma cell model membranes differing in the level and the kind of anionic lipids (phosphatidylserine, sialic acid-containing ganglioside GM3 or their mixture) were done. As evidenced the results the effect of DEAE-dextran on the model system is determined by anionic lipid-polymer electrostatic interactions. However, the magnitude of the effect of cationic polymer is strongly dependent on the kind of anionic lipid in the model system. Namely, the packing and ordering of the mixtures containing ganglioside GM3 were more affected by DEAE-dextran than phosphatidylserine-containing monolayers. Although the experiments were done on model systems and therefore further studies are highly needed, the collected data may indicate that ganglioside may be important in the differentiation of the effect of cationic dextran on membranes.

  2. Transpulmonary plasma ET-1 and nitrite differences in high altitude pulmonary hypertension.

    Science.gov (United States)

    Berger, Marc M; Dehnert, Christoph; Bailey, Damian M; Luks, Andrew M; Menold, Elmar; Castell, Christian; Schendler, Guido; Faoro, Vitalie; Mairbäurl, Heimo; Bärtsch, Peter; Swenson, Erik R

    2009-01-01

    Berger, Marc M., Christoph Dehnert, Damian M. Bailey, Andrew M. Luks, Elmar Menold, Christian Castell, Guido Schendler, Vitalie Faoro, Heimo Mairbäurl, Peter Bärtsch, and Eric R. Swenson. Transpulmonary plasma ET-1 and nitrite differences in high altitude pulmonary hypertension. High Alt. Med. Biol. 10:17-24, 2009.- Thirty-four mountaineers were studied at low (110 m) and high altitude (4559 m) to evaluate if increased pulmonary artery systolic pressure (PASP) at high altitude is associated with increased pulmonary endothelin-1 (ET-1) availability and alterations in nitrite metabolism across the lung. Blood samples were obtained using central venous and radial artery catheters for plasma ET-1 and nitrite. Pulmonary blood flow was measured by inert gas rebreathing to calculate transpulmonary exchange of plasma ET-1 and nitrite, and PASP was assessed by transthoracic Doppler echocardiography. After ascent to high altitude, PASP increased from 23 +/- 4 to 39 +/- 10 mmHg. Arterial and central venous plasma ET-1 increased, while plasma nitrite did not change significantly. At low altitude there was a transpulmonary loss of plasma ET-1, but a transpulmonary gain at high altitude. In contrast was a transpulmonary gain of plasma nitrite at low altitude and a transpulmonary loss at high altitude. PASP positively correlated with a transpulmonary gain of plasma ET-1 and negatively correlated with a transpulmonary loss of plasma nitrite. These results suggest that a transpulmonary gain of plasma ET- 1 is associated with higher PASP at high altitude. Transpulmonary loss of plasma nitrite indicates either less pulmonary nitric oxide (NO) production, which contributes to higher PASP, or increased NO bioavailability arising from nitrite reduction, which may oppose ET-1-mediated vasoconstriction.

  3. Nitric oxide generation from heme/copper assembly mediated nitrite reductase activity.

    Science.gov (United States)

    Hematian, Shabnam; Siegler, Maxime A; Karlin, Kenneth D

    2014-06-01

    Nitric oxide (NO) as a cellular signaling molecule and vasodilator regulates a range of physiological and pathological processes. Nitrite (NO2 (-)) is recycled in vivo to generate nitric oxide, particularly in physiologic hypoxia and ischemia. The cytochrome c oxidase binuclear heme a 3/CuB active site is one entity known to be responsible for conversion of cellular nitrite to nitric oxide. We recently reported that a partially reduced heme/copper assembly reduces nitrite ion, producing nitric oxide; the heme serves as the reductant and the cupric ion provides a Lewis acid interaction with nitrite, facilitating nitrite (N-O) bond cleavage (Hematian et al., J. Am. Chem. Soc. 134:18912-18915, 2012). To further investigate this nitrite reductase chemistry, copper(II)-nitrito complexes with tridentate and tetradentate ligands were used in this study, where either O,O'-bidentate or O-unidentate modes of nitrite binding to the cupric center are present. To study the role of the reducing ability of the ferrous heme center, two different tetraarylporphyrinate-iron(II) complexes, one with electron-donating para-methoxy peripheral substituents and the other with electron-withdrawing 2,6-difluorophenyl substituents, were used. The results show that differing modes of nitrite coordination to the copper(II) ion lead to differing kinetic behavior. Here, also, the ferrous heme is in all cases the source of the reducing equivalent required to convert nitrite to nitric oxide, but the reduction ability of the heme center does not play a key role in the observed overall reaction rate. On the basis of our observations, reaction mechanisms are proposed and discussed in terms of heme/copper heterobinuclear structures.

  4. Haematological and ion regulatory effects of nitrite in the air-breathing snakehead fish Channa striata.

    Science.gov (United States)

    Lefevre, Sjannie; Jensen, Frank B; Huong, Do T T; Wang, Tobias; Phuong, Nguyen T; Bayley, Mark

    2012-08-15

    The tolerance and effects of nitrite on ion balance and haematology were investigated in the striped snakehead, Channa striata Bloch 1793, which is an air-breathing fish with reduced gills of importance for aquaculture in South East Asia. C. striata was nitrite tolerant with a 96 h LC50 of 4.7 mM. Effects of sub-lethal exposures to nitrite (0mM, 1.4mM, and 3.0mM) were determined during a 7-day exposure period. Plasma nitrite increased, but the internal concentration remained well below ambient levels. Extracellular nitrate rose by several mM, indicating that a large proportion of the nitrite taken up was converted to nitrate. Nitrite reacted with erythrocyte haemoglobin (Hb) causing methaemoglobin (metHb) to increase to 30% and nitrosylhaemoglobin (HbNO) to increase to 10% of total Hb. Both metHb and HbNO stabilised after 4 days, and functional Hb levels accordingly never fell below 60% of total Hb. Haematocrit and total Hb were unaffected by nitrite. Although the effects of nitrite exposure seemed minor in terms of plasma nitrite and metHb increases, ion balance was strongly affected. In the high exposure group, total osmolality decreased from 320 mOsm to 260 mOsm, and plasma sodium from 150 mM to 120 mM, while plasma chloride fell from 105 mM to 60mM and plasma bicarbonate rose from 12 mM in controls to 20mM in exposed fish. The extreme changes in ion balance in C. striata are different from the response reported in other fish, and further studies are needed to investigate the mechanism behind the observed changes in regulation.

  5. Multiple metabolisms constrain the anaerobic nitrite budget in the Eastern Tropical South Pacific

    Science.gov (United States)

    Babbin, Andrew R.; Peters, Brian D.; Mordy, Calvin W.; Widner, Brittany; Casciotti, Karen L.; Ward, Bess B.

    2017-02-01

    The Eastern Tropical South Pacific is one of the three major oxygen deficient zones (ODZs) in the global ocean and is responsible for approximately one third of marine water column nitrogen loss. It is the best studied of the ODZs and, like the others, features a broad nitrite maximum across the low oxygen layer. How the microbial processes that produce and consume nitrite in anoxic waters interact to sustain this feature is unknown. Here we used 15N-tracer experiments to disentangle five of the biologically mediated processes that control the nitrite pool, including a high-resolution profile of nitrogen loss rates. Nitrate reduction to nitrite likely depended on organic matter fluxes, but the organic matter did not drive detectable rates of denitrification to N2. However, multiple lines of evidence show that denitrification is important in shaping the biogeochemistry of this ODZ. Significant rates of anaerobic nitrite oxidation at the ODZ boundaries were also measured. Iodate was a potential oxidant that could support part of this nitrite consumption pathway. We additionally observed N2 production from labeled cyanate and postulate that anammox bacteria have the ability to harness cyanate as another form of reduced nitrogen rather than relying solely on ammonification of complex organic matter. The balance of the five anaerobic rates measured—anammox, denitrification, nitrate reduction, nitrite oxidation, and dissimilatory nitrite reduction to ammonium—is sufficient to reproduce broadly the observed nitrite and nitrate profiles in a simple one-dimensional model but requires an additional source of reduced nitrogen to the deeper ODZ to avoid ammonium overconsumption.

  6. Calcium ameliorates diarrhea in immune compromised children

    OpenAIRE

    Cheng, Sam X.; Bai, Harrison X.; Gonzalez-Peralta, Regino; Mistry, Pramod K.; Gorelick, Fred S.

    2013-01-01

    Treatment of infectious diarrheas remains a challenge, particularly in immunocompromised patients in whom infections usually persist and resultant diarrhea is often severe and protracted. Children with infectious diarrhea who become dehydrated are normally treated with oral or intravenous rehydration therapy. Although rehydration therapy can replace the loss of fluid, it does not ameliorate diarrhea. Thus, over the past decades, there has been continuous effort to search for ways to safely st...

  7. Solubilities of sodium nitrate, sodium nitrite, and sodium aluminate in simulated nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, D.A.; Herting, D.L.

    1984-09-01

    Solubilities were determined for sodium nitrate, sodium nitrite, and sodium aluminate in synthetic nuclear waste liquor. Solubilities were determined as a function of temperature and solution composition (concentrations of sodium hydroxide, sodium nitrate, sodium nitrite, and sodium aluminate). Temperature had the greatest effect on the solubilities of sodium nitrate and sodium nitrite and a somewhat lesser effect on sodium aluminate solubility. Hydroxide had a great effect on the solubilities of all three salts. Other solution components had minor effects. 2 references, 8 figures, 11 tables.

  8. Popping and snorting volatile nitrites: a current fad for getting high.

    Science.gov (United States)

    Sigell, L T; Kapp, F T; Fusaro, G A; Nelson, E D; Falck, R S

    1978-10-01

    In certain social circles a variety of volatile nitrites are being used extensively to expand creativity, stimulate music appreciation, promote a sense of abandon in dancing, and intensify sexual experience. Soon after amyl nitrite (the prototype of this group) became a prescription drug, legally produced substitutes appeared and were sold as room odorizers. Analyses of eight of these substitutes showed them to contain isomers of butyl or amyl alcohol and a corresponding nitrite. The authors describe the context of use of these products and their desired and adverse effects.

  9. Stress Corrosion Cracking of an Austenitic Stainless Steel in Nitrite-Containing Chloride Solutions

    Directory of Open Access Journals (Sweden)

    R. K. Singh Raman

    2014-12-01

    Full Text Available This article describes the susceptibility of 316L stainless steel to stress corrosion cracking (SCC in a nitrite-containing chloride solution. Slow strain rate testing (SSRT in 30 wt. % MgCl2 solution established SCC susceptibility, as evidenced by post-SSRT fractography. Addition of nitrite to the chloride solution, which is reported to have inhibitive influence on corrosion of stainless steels, was found to increase SCC susceptibility. The susceptibility was also found to increase with nitrite concentration. This behaviour is explained on the basis of the passivation and pitting characteristics of 316L steel in chloride solution.

  10. A carbon nanotube/polyvanillin composite film as an electrocatalyst for the electrochemical oxidation of nitrite and its application as a nitrite sensor

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Dongyun [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China); Hu Chengguo [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China)], E-mail: cghu@whu.edu.cn; Peng Yanfen [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China); Hu Shengshui [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China)], E-mail: sshu@whu.edu.cn

    2009-08-30

    We report a simple method for the stable dispersion of multi-walled carbon nanotubes (MWNTs) in water by vanillin and controllable surface addition onto carbon fiber microelectrodes (CFE) via electropolymerization. We have characterized these polyvanillin-carbon nanotube (PVN-MWNT) composite films with techniques including scanning electron microscopy (SEM), infrared spectroscopy (IR) and voltammetry. These investigations showed that the films have a uniform porous nanostructure with a large surface area. This PVN-MWNT composite-modified CFE (PVN-MWNT/CFE) exhibited a sensitive response to the electrochemical oxidation of nitrite. Under optimal working conditions, the oxidation peak current of nitrite linearly increased with its concentration in the range of 0.2 {mu}M-3.1 mM, with the system exhibiting a lower detection limit of 50 nM (S/N = 3). We successfully applied the PVN-MWNT/CFE system to the determination of nitrite from lake water. The efficient recovery of nitrite indicated that this electrode was able to detect nitrite in real samples.

  11. The Effect of Influent Characteristics and Operational Conditions over the Performance and Microbial Community Structure of Partial Nitritation Reactors

    Directory of Open Access Journals (Sweden)

    Alejandro Rodriguez-Sanchez

    2014-06-01

    Full Text Available Nitrogen is a main contaminant of wastewater worldwide. Novel processes for nitrogen removal have been developed over the last several decades. One of these is the partial nitritation process. This process includes the oxidation of ammonium to nitrite without the generation of nitrate. The partial nitritation process has several advantages over traditional nitrification-denitrification processes for nitrogen removal from wastewaters. In addition, partial nitritation is required for anammox elimination of nitrogen from wastewater. Partial nitritation is affected by operational conditions and substances present in the influent, such as quinolone antibiotics. In this review, the impact that several operational conditions, such as temperature, pH, dissolved oxygen concentration, hydraulic retention time and solids retention time, have over the partial nitritation process is covered. The effect of quinolone antibiotics and other emerging contaminants are discussed. Finally, future perspectives for the partial nitritation process are commented upon.

  12. Effect of Initial nitrite concentration on growth of spirulina platensis; Supirurina no zoshoku ni oyobosu ashosan ion shonodo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Y.; Obata, E.; Kuga, Y.; Ando, K. [Muroran Inst. of Tech., Hokkaido (Japan). Dept. of Applied Chemistry; Yamada, S.

    2000-09-10

    The effect of the initial nitrite concentration on the growth of S. platensis was experimentally investigated using the medium added to the sodium nitrite of 0.0-1.6 kg{center_dot}m{sup -3}. When the initial nitrite concentration is smaller than 0.8 kg{center_dot}m{sup -3}, the growth rate is greater than that without nitrite. The specific growth rate had the maximum value and is approximately 1.3 times that of a standard medium when the range of the initial nitrite concentration is 0.3-0.4 kg{center_dot}m{sup -3}. When the initial nitrite concentration is greater than 0.8 kg{center_dot}m{sup -3}, the growth rate was smaller than that of a standard medium due to nitrite inhibition. (author)

  13. Scale up of dextran production from a mutant of Pediococcus pentosaceus (SPAm using optimized medium in a bioreactor

    Directory of Open Access Journals (Sweden)

    Seema Patel

    2011-12-01

    Full Text Available The mutant of Pediococcus pentosaceus (SPAm produced earlier by UV-mutagenesis exhibiting higher dextransucrase activity as compared to wild-type was used. The generated mutant SPAm gave 12.2 mg/ml, a 20% higher dextran than wild-type. Response surface methodology was carried out for further enhancement of dextran production. To enhance dextran production by the mutant SPAm, Plackett-Burman Design and a 2² full factorial Central Composite Design was employed. After response optimization, the optimum concentration of sucrose and yeast extract was 5.115% (w/v and 0.635% (w/v, respectively. The experimental values of dextran 36.0 mg/ml at flask level and 35.0 mg/ml at bioreactor level were in good agreement with the predicted value of 40.8 mg/ml. The increase in dextran production by the mutant SPAm using the optimized medium was 3 fold higher as compared to unoptimized medium.

  14. Omega 3 fatty acids supplementation has an ameliorative effect in experimental ulcerative colitis despite increased colonic neutrophil infiltration.

    Science.gov (United States)

    Varnalidis, Ioannis; Ioannidis, Orestis; Karamanavi, Elisavet; Ampas, Zafeiris; Poutahidis, Theofilos; Taitzoglou, Ioannis; Paraskevas, George; Botsios, Dimitrios

    2011-10-01

    omega 3 polyunsaturated fatty acids have anti-inflammatory properties and can be beneficial in the treatment of inflammatory diseases, such as ulcerative colitis. Dextran sodium sulphate (DSS) colitis in rats appears to mimic nearly all of the morphological characteristics and lesion distributions of ulcerative colitis. The purpose of the current study was to investigate the efficacy of omega 3 fatty acids in the treatment of experimental ulcerative colitis. thirty-six Wistar rats were randomly assigned to group A or group B receiving 5% dextran sulfate sodium (DSS) in their drinking water for eight days. For the next eight days post-DSS, group A animals received tap-water, and group B animals were fed a nutritional solution containing high levels of omega 3 polyunsaturated fatty acids (ProSure®, Abbott Laboratories, Zwolle, Netherlands) once per day, administrated with a orogastric feeding tube. animals fed an omega 3 rich diet exhibited a statistically significant increase in hematocrit and hemoglobin levels, compared to animals drinking tap water, and a trend towards histopathological and clinical improvement, with the administration of omega 3 fatty acids ameliorating epithelial erosion by day 8 post-DSS, but no statistically significant difference was observed between group A and group B animals at 4 or 8 days post-DSS. Also, a statistically significant increase in neutrophil infiltration was observed, as depicted by myelohyperoxidase activity. our findings support a positive role of omega 3 polyunsaturated fatty acids supplementation in an experimental model of ulcerative colitis despite the increased colonic neutrophil infiltration. Further studies are needed in order to investigate the role of increased neutrophils in colonic mucosa.

  15. Addition of Berberine to 5-Aminosalicylic Acid for Treatment of Dextran Sulfate Sodium-Induced Chronic Colitis in C57BL/6 Mice.

    Science.gov (United States)

    Li, Yan-hong; Zhang, Man; Xiao, Hai-tao; Fu, Hai-bo; Ho, Alan; Lin, Cheng-yuan; Huang, Yu; Lin, Ge; Bian, Zhao-xiang

    2015-01-01

    Ulcerative colitis (UC) is a common chronic remitting disease but without satisfactory treatment. Alternative medicine berberine has received massive attention for its potential in UC treatment. Conventional therapies with the addition of berberine are becoming attractive as novel therapies in UC. In the present study, we investigated the preclinical activity of a conventional oral 5-aminosalicylic acid (5-ASA) therapy plus berberine in experimental colitis. A subclinical dose of 5-ASA (200 mg/kg/day) alone or 5-ASA plus berberine (20 mg/kg/day) was orally administered for 30 days to C57BL/6 mice with colitis induced by three cycles of 2% dextran sulfate sodium (DSS). The disease severity, inflammatory responses, drug accumulation and potential toxicity of colitis mice were examined. The results showed that comparing to 5-ASA alone, 5-ASA plus berberine more potently ameliorated DSS-induced disease severity, colon shortening, and colon histological injury. Further, the up-regulation in mRNA level of colonic TNF-α as well as NFκB and JAK2 phosphorylation caused by DSS were more pronouncedly reversed in animals treated with the combination therapy than those treated with 5-ASA alone. Moreover, the addition of berberine to 5-ASA more significantly inhibited lymphocyte TNF-α secretion of DSS mice than 5-ASA alone. In the meanwhile, no extra drug accumulation or potential toxicity to major organs of colitis mice was observed with this combination treatment. In summary, our studies provide preclinical rationale for the addition of berberine to 5-ASA as a promising therapeutic strategy in clinic by reducing dose of standard therapy.

  16. The effects of a TGR5 agonist and a dipeptidyl peptidase IV inhibitor on dextran sulfate sodium-induced colitis in mice.

    Science.gov (United States)

    Sakanaka, Taisuke; Inoue, Takuya; Yorifuji, Naoki; Iguchi, Munetaka; Fujiwara, Kaori; Narabayashi, Ken; Kakimoto, Kazuki; Nouda, Sadaharu; Okada, Toshihiko; Kuramoto, Takanori; Ishida, Kumi; Abe, Yosuke; Takeuchi, Toshihisa; Umegaki, Eiji; Akiba, Yasutada; Kaunitz, Jonathan D; Higuchi, Kazuhide

    2015-03-01

    Luminal nutrients stimulate enteroendocrine L cells to release gut hormones, including intestinotrophic glucagon-like peptide-2 (GLP-2). Because L cells express the bile acid receptor TGR5 and dipeptidyl peptidase-IV (DPPIV) rapidly degrades GLPs, we hypothesized that luminal TGR5 activation may attenuate intestinal injury via GLP-2 release, which is enhanced by DPPIV inhibition. Intestinal injury was induced in mice by administration of dextran sulfate sodium (DSS) in drinking water (free access to water containing 5% DSS for 7 days). The selective TGR5 agonist betulinic acid (BTA) and the DPPIV inhibitor sitagliptin phosphate monohydrate (STG) were administered orally for 7 days. Male C57BL/6 mice (6-7 weeks old) were divided into five groups: normal control group, disease control group, BTA low group (drinking water containing 15 mg/L BTA), BTA high group (50 mg/L BTA), and BTA high + STG (3 mg/kg, i.g.) group. The selective TGR5 agonist BTA dose-dependently suppressed disease activity index and mRNA expression of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in the colon. Nevertheless, STG administration had little additive effect on BTA-induced protection. Fibroblast activation protein mRNA expression, but not expression of other DPP family members, was increased in the colon of DSS-treated mice with increased mucosal DPPIV. Co-administration of the selective GLP-2 antagonist GLP-2 (3-33) reversed the effect of BTA. The selective TGR5 agonist BTA ameliorated DSS-induced colitis in mice via the GLP-2 pathway with no effect of DPPIV inhibition, suggesting that other DPP enzymatic activity is involved in GLP-2 degradation. © 2015 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  17. The Anti-Inflammatory Effect and Intestinal Barrier Protection of HU210 Differentially Depend on TLR4 Signaling in Dextran Sulfate Sodium-Induced Murine Colitis.

    Science.gov (United States)

    Lin, Sisi; Li, Yongyu; Shen, Li; Zhang, Ruiqin; Yang, Lizhi; Li, Min; Li, Kun; Fichna, Jakub

    2017-02-01

    Ulcerative colitis (UC) is strongly associated with inflammation and intestinal barrier disorder. The nonselective cannabinoid receptor agonist HU210 has been shown to ameliorate inflamed colon in colitis, but its effects on intestinal barrier function and extraintestinal inflammation are unclear. To investigate the effects and the underlying mechanism of HU210 action on the UC in relation to a role of TLR4 and MAP kinase signaling. Wild-type (WT) and TLR4 knockout (Tlr4 (-/-)) mice were exposed to 4% dextran sulfate sodium (DSS) for 7 days. The effects of HU210 on inflammation and intestinal barrier were explored. Upon DSS challenge, mice suffered from bloody stool, colon shortening, intestinal mucosa edema, pro-inflammatory cytokine increase and intestinal barrier destruction with goblet cell depletion, increased intestinal microflora accompanied with elevated plasma lipopolysaccharide, reduced mRNA expression of the intestinal tight junction proteins, and abnormal ratio of CD4(+)/CD8(+) T cells in the intestinal Peyer's patches. Pro-inflammatory cytokines in the plasma and the lung, as well as pulmonary myeloperoxidase activity, indicators of extraintestinal inflammation were increased. Protein expression of p38α and pp38 was up-regulated in the colon of WT mice. Tlr4 (-/-) mice showed milder colitis. HU210 reversed the intestinal barrier changes in both strains of mice, but alleviated inflammation only in WT mice. Our study indicates that in experimental colitis, HU210 displays a protective effect on the intestinal barrier function independently of the TLR4 signaling pathway; however, in the extraintestinal tissues, the anti-inflammatory action seems through affecting TLR4-mediated p38 mitogen-activated protein kinase pathway.

  18. Ginsenoside Metabolite Compound K Promotes Recovery of Dextran Sulfate Sodium-Induced Colitis and Inhibits Inflammatory Responses by Suppressing NF-κB Activation

    Science.gov (United States)

    Li, Juan; Zhong, Wei; Wang, Weiwei; Hu, Shaoping; Yuan, Jiahui; Zhang, Bing; Hu, Tianhui; Song, Gang

    2014-01-01

    Phytogenic compounds with anti-oxidant and anti-inflammatory properties, such as ginsenoside metabolite compound K (CK) or berberine (BBR), are currently discussed as promising complementary agents in the prevention and treatment of cancer and inflammation. The latest study showed that ginsenoside Rb1 and its metabolites could inhibit TNBS-induced colitis injury. However, the functional mechanisms of anti-inflammation effects of ginsenoside, particularly its metabolite CK are still not clear. Here, using dextran sulfate sodium (DSS)-induced colitis in mice, clinical parameters, intestinal integrity, pro-inflammatory cytokines production, and signaling pathways in colonic tissues were determined. In mild and sever colitis mice, CK and BBR (as a positive agent) alleviated colitis histopathology injury, ameliorated myeloperoxidase (MPO) activity, reduced pro-inflammatory cytokines production, such as, IL-6, IL-1β, TNF-α, and increased anti-inflammatory cytokine IL-10 production in both mice colon tissues and blood. Nevertheless, the results revealed that CK and BBR inhibited NF-κB p65 nuclear translocation, downregulated p-IκBα and upregulated IκBα, indicating that CK, as well as BBR, suppressed the activation of the NF-κB pathway in the progression of colitis with immunofluorescence, immunohistochemical and western blotting analysis. Furthermore, CK inhibited pro-inflammatory cytokines production in LPS-activated macrophages via down-regulation of NF-κB signaling pathway. Taken together, our results not only reveal that CK promotes the recovery of the progression of colitis and inhibits the inflammatory responses by suppressing NF-κB activation, but also suggest that CK downregulates intestinal inflammation through regulating the activation of macrophages and pro-inflammatory cytokines production. PMID:24504372

  19. LONG-LIVED BONE MARROW PLASMA CELLS DURING IMMUNE RESPONSE TO ALPHA (1→3 DEXTRAN

    Directory of Open Access Journals (Sweden)

    I. N. Chernyshova

    2015-01-01

    Full Text Available Production kinetics and some functional properties of long-lived marrow plasma cells were studied in mice immunized with T-independent type 2 antigens. Alpha (1→3 dextran was used as an antigen for immunization. The mice were immunized by dextran, and the numbers of IgM antibody producing cells were determined by ELISPOT method. The cell phenotype was determined by cytofluorimetric technique. In the area of normal bone marrow lymphocytes ~4% of T and ~85% of B cells were detected. About 35% of the cells expressed a plasmocyte marker (CD138; 3% were CD138+IgM+, and about 6% of the lymphocytes were double-positive for CD138+IgA+. Among spleen lymphocytes, 50% of T and 47% of B cells were detected. About 1.5% lymphocytes were CD138+, and 0.5% were positive for CD138 and IgM. Time kinetics of antibody-producing cells in bone marrow and spleen was different. In spleen populations, the peak amounts of antibody-secreting cells have been shown on the day 4; the process abated by the day 28. Vice versa, the numbers of the antibody-producing cells in bone marrow started to increase on the day 4. The process reached its maximum on day 14, and after 28th day became stationary. The in vitro experiments have shown that supplementation of bone marrow cells from immune mice with dextran did not influence their functional activity. It was previously shown for cells responding to T-dependent antigens only. A specific marker for the long-lived plasma cells is still unknown. However, these cells possess a common CD138 marker specific for all plasma cells. A method for isolation of bone marrow CD138+ cells was developed. The CD138+ cells were of 87-97% purity, being enriched in long-lived bone marrow cells, and produced monospecific antibodies. 

  20. Aldehyded Dextran and ε-Poly(L-lysine Hydrogel as Nonviral Gene Carrier

    Directory of Open Access Journals (Sweden)

    Yumiko Togo

    2013-01-01

    Full Text Available Background. The expression term of the gene transfected in cells needs to belong enough inorder to make a gene therapy clinically effective. The controlled release of the transfected gene can be utilized. The new biodegradable hydrogel material created by 20 w/w% aldehyded dextran and 10 w/w% ε-poly(L-lysine (ald-dex/PLL was developed. We examined whether it could be as a nonviral carrier of the gene transfer. Methods. A plasmid (Lac-Z was mixed with ald-dex/PLL. An in vitro study was performed to assess the expression of Lac-Z with X-gal stain after gene transfer into the cultured 293 cells and bone marrow cells. As a control group, PLL was used as a cationic polymer. Results. We confirmed that the transfection efficiency of the ald-dex/PLL had a higher transfection efficiency than PLL in 293 cells (plasmid of 2 μg: ald-dex/PLL 1.1%, PLL 0.23%, plasmid of 16 μg: ald-dex/PLL 1.23%, PLL 0.48%. In bone marrow cells, we confirmed the expression of Lac-Z by changing the quantity of aldehyded dextran. In the groups using ald-dextran of the quantity of 1/4 and 1/12 of PLL, their transfection efficiency was 0.43% and 0.41%, respectively. Conclusions. This study suggested a potential of using ald-dex/PLL as a non-carrier for gene transfer.

  1. Phase Transition and Micellization of Temperature Responsive Dextran-graft-poly (N-isopropylacrylamide) Polymers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Phase behavior and micellization of dextran-graft-poly (N-isopropylacrylamide) (PNIPAAm) polymers in aqueous solution are investigated in this paper using DSC and AFM methods. It is found that with the increase of grafting (G%) of the copolymers the endothermic enthalpy during the phase transition increases significantly and the transition temperature decreases slightly. The phase transition behavior of the copolymers is scanning rate dependent. Micelles are formed whenever the solution temperature is raised above the LCST of the copolymers. It is proposed that by using this thermal responsive property of the copolymers, drugs could be incorporated into the micelles without employing any organic solvent.

  2. Effect of Arctium lappa L.in the dextran sulfate sodium colitis mouse model

    Institute of Scientific and Technical Information of China (English)

    Tzou-Chi; Huang; Shinn-Shyong; Tsai

    2010-01-01

    AIM:To analyze the possible protective role of Arctium lappa L.(AL)in a murine model of ulcerative colitis(UC).METHODS:BALB/c mice were administered 100 mg/kg AL powder orally each day.After 7 d,colitis was induced by administration of dextran sulfate sodium(DSS)(5% W/V)in drinking water for a further 8 consecutive days.Diarrhea and bloody stools as well as colonic histology were observed.The level of interleukin-6(IL-6)and tu-mor necrosis factor-α(TNF-α)in colonic sections were detected by immunohistochemi...

  3. Selective fluorescent detection of aspartic acid and glutamic acid employing dansyl hydrazine dextran conjugate.

    Science.gov (United States)

    Nasomphan, Weerachai; Tangboriboonrat, Pramuan; Tanapongpipat, Sutipa; Smanmoo, Srung

    2014-01-01

    Highly water soluble polymer (DD) was prepared and evaluated for its fluorescence response towards various amino acids. The polymer consists of dansyl hydrazine unit conjugated into dextran template. The conjugation enhances higher water solubility of dansyl hydrazine moiety. Of screened amino acids, DD exhibited selective fluorescence quenching in the presence of aspartic acid (Asp) and glutamic acid (Glu). A plot of fluorescence intensity change of DD against the concentration of corresponding amino acids gave a good linear relationship in the range of 1 × 10(-4) M to 25 × 10(-3) M. This establishes DD as a potential polymeric sensor for selective sensing of Asp and Glu.

  4. Dextran Sulfate Sodium (DSS)-Induced Acute Colitis in the Rat.

    Science.gov (United States)

    Martin, Jérôme C; Bériou, Gaëlle; Josien, Régis

    2016-01-01

    Inflammatory bowel diseases (IBDs) are complex multifactorial disease thought to result from inappropriate immune responses to the gut microbiota, in genetically susceptible individuals, under the influence of environmental factors. Among the different animal models developed to help in understanding IBDs pathophysiological mechanisms as well as to achieve pharmacological preclinical studies, the dextran sulfate sodium (DSS)-induced colitis model is the most widely used because of its simplicity, cost-effectiveness, and similarity with human IBDs. This section provides with a detailed protocol that we validated in our laboratory to perform DSS-induced acute colitis in the Sprague-Dawley (SPD) rat.

  5. β-Cyclodextrin-dextran polymers for the solubilization of poorly soluble drugs

    DEFF Research Database (Denmark)

    Di Cagno, Massimiliano; Nielsen, Thorbjørn Terndrup; Lambertsen Larsen, Kim

    2014-01-01

    NMR and isothermal titration calorimetry. Moreover, thermodynamic parameters of the complexation reaction between β-CD units and drug molecules in terms of molar enthalpy of complexation, equilibrium constant, and stability of the β-CD units/drug molecules complexes were also measured. For evaluation...... of solubilization efficiencies, phase-solubility diagrams where made employing two poorly soluble model drugs, one dissociating (ibuprofen, IBP) and one pH independent (hydrocortisone, HC). Thermodynamic results demonstrated that the presence of the dextran-back bone structure improves complexation efficiency...

  6. Measurement of nitrite and nitrate in saliva of children with different caries activity

    National Research Council Canada - National Science Library

    Ghasempour, Maryam; Qujeq, Durdi; Rabiee, Maryam; Hamzeh, Mahtab

    2014-01-01

    .... Nitrate is a natural compound found in fruits and vegetables and when secreted in saliva, is reduced to nitrite through bacterial respiration and subsequently reduced to nitric oxide in acidic condition...

  7. Nitrite-induced enhancement of toxicity of phenanthrene in fish and its implications for coastal waters

    Digital Repository Service at National Institute of Oceanography (India)

    Shailaja, M.S.; Rodrigues, A.

    and phenanthrene, a polycyclic aromatic hydrocarbon. Analyses of different biomarkers in the treated fish indicated significant increase in the metabolism of phenanthrene as a result of exposure to nitrite. For example, the activity of the biotransformation enzyme...

  8. Nitrite Biosensing via Selective Enzymes—A Long but Promising Route

    Directory of Open Access Journals (Sweden)

    M. Gabriela Almeida

    2010-12-01

    Full Text Available The last decades have witnessed a steady increase of the social and political awareness for the need of monitoring and controlling environmental and industrial processes. In the case of nitrite ion, due to its potential toxicity for human health, the European Union has recently implemented a number of rules to restrict its level in drinking waters and food products. Although several analytical protocols have been proposed for nitrite quantification, none of them enable a reliable and quick analysis of complex samples. An alternative approach relies on the construction of biosensing devices using stable enzymes, with both high activity and specificity for nitrite. In this paper we review the current state-of-the-art in the field of electrochemical and optical biosensors using nitrite reducing enzymes as biorecognition elements and discuss the opportunities and challenges in this emerging market.

  9. Nitrification expanded: discovery, physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi

    National Research Council Canada - National Science Library

    Sorokin, Dimitry Y; Lücker, Sebastian; Vejmelkova, Dana; Kostrikina, Nadezhda A; Kleerebezem, Robbert; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; Le Paslier, Denis; Muyzer, Gerard; Wagner, Michael; van Loosdrecht, Mark C M; Daims, Holger

    2012-01-01

    Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, a major process of the biogeochemical nitrogen cycle, but the recognized diversity of this guild is surprisingly low and only two bacterial phyla contain known NOB...

  10. Expanded metabolic versatility of ubiquitous nitrite-oxidizing bacteria from the genus Nitrospira

    DEFF Research Database (Denmark)

    Koch, Hanna; Lücker, Sebastian; Albertsen, Mads

    2015-01-01

    Nitrospira are a diverse group of nitrite-oxidizing bacteria and among the environmentally most widespread nitrifiers. However, they remain scarcely studied and mostly uncultured. Based on genomic and experimental data from Nitrospira moscoviensis representing the ubiquitous Nitrospira lineage II...

  11. Controls of nitrite oxidation in ammonia-removing biological air filters

    DEFF Research Database (Denmark)

    Juhler, Susanne; Ottosen, Lars Ditlev Mørck; Nielsen, Lars Peter

    2008-01-01

    In biological air filters ammonia is removed due to the action of Ammonia Oxidizing Bacteria (AOB) resulting in nitrite accumulation exceeding 100 mM. Among filters treating exhaust air from pig facilities successful establishment of Nitrite Oxidizing Bacteria (NOB) sometimes occurs, resulting...... in accumulation of nitrate rather than nitrite and a significant decline in pH. As a consequence, ammonia is removed more efficiently, but heterotrophic oxidation of odorous compounds might be inhibited.  To identify the controlling mechanisms of nitrite oxidation, full-scale biological air filters were...... investigated applying a broad in situ approach. Bacterial distribution and chemical gradients were examined at both a macro scale from filter inlet towards outlet and on a micro scale within the intact biofilm, applying Fluorescence in situ Hybridization (FISH), electrochemical microsensors, and chemical...

  12. Harvesting biohydrogen from cellobiose from sulfide or nitrite-containing wastewaters using Clostridium sp. R1.

    Science.gov (United States)

    Ho, Kuo-Ling; Lee, Duu-Jong

    2011-09-01

    Harvesting biohydrogen from inhibiting wastewaters is of practical interest since the toxicity of compounds in a wastewater stream commonly prevents the bioenergy content being recovered. The isolated Clostridium sp. R1 is utilized to degrade cellobiose in sulfide or nitrite-containing medium for biohydrogen production. The strain can effectively degrade cellobiose free of severe inhibitory effects at up to 200 mgl(-1) sulfide or to 5 mgl(-1) nitrite, yielding hydrogen at >2.0 mol H2 mol(-1) cellobiose. Principal metabolites of cellobiose fermentation are acetate and butyrate, with the concentration of the former increases with increasing sulfide and nitrite concentrations. The isolated strain can yield hydrogen from cellobiose in sulfide-laden wastewaters. However, the present of nitrite significantly limit the efficiency of the biohydrogen harvesting process.

  13. Nitrogen polishing in a fully anoxic anammox MBBR treating mainstream nitritation-denitritation effluent.

    Science.gov (United States)

    Regmi, Pusker; Holgate, Becky; Miller, Mark W; Park, Hongkeun; Chandran, Kartik; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2016-03-01

    As nitrogen discharge limits are becoming more stringent, short-cut nitrogen systems and tertiary nitrogen polishing steps are gaining popularity. For partial nitritation or nitritation-denitritation systems, anaerobic ammonia oxidation (anammox) polishing may be feasible to remove residual ammonia and nitrite from the effluent. Nitrogen polishing of mainstream nitritation-denitritation system effluent via anammox was studied at 25°C in a fully anoxic moving bed bioreactor (MBBR) (V = 0.45 m(3) ) over 385 days. Unlike other anammox based processes, a very fast startup of anammox MBBR was demonstrated, despite nitrite limited feeding conditions (influent nitrite = 0.7 ± 0.59 mgN/L, ammonia = 6.13 ± 2.86 mgN/L, nitrate = 3.41 ± 1.92 mgN/L). The nitrogen removal performance was very stable within a wide range of nitrogen inputs. Anammox bacteria (AMX) activity up to 1 gN/m(2) /d was observed which is comparable to other biofilm-based systems. It is generally believed that nitrate production limits nitrogen removal through AMX metabolism. However, in this study, anammox MBBR demonstrated ammonia, nitrite, and nitrate removal at limited chemical oxygen demand (COD) availability. AMX and heterotrophs contributed to 0.68 ± 0.17 and 0.32 ± 0.17 of TIN removal, respectively. It was speculated that nitrogen removal might be aided by denitratation which could be due to heterotrophs or the recently discovered ability for AMX to use short-chain fatty acids to reduce nitrate to nitrite. This study demonstrates the feasibility of anammox nitrogen polishing in an MBBR is possible for nitritation-denitration systems.

  14. Analysis of responses to glyceryl trinitrate and sodium nitrite in the intact chest rat.

    Science.gov (United States)

    Nossaman, Bobby D; Pankey, Edward A; Badejo, Adeleke R; Casey, David B; Uppu, Satvika; Murthy, Subramanyam N; Kadowitz, Philip J

    2012-05-15

    Responses to glyceryl trinitrate/nitroglycerin (GTN), S-nitrosoglutathione (GSNO), and sodium nitrite were compared in the intact chest rat. The iv injections of GTN, sodium nitrite, and GSNO produced dose-dependent decreases in pulmonary and systemic arterial pressures. In as much as cardiac output was not reduced, the decreases in pulmonary and systemic arterial pressures indicate that GTN, sodium nitrite, and GSNO have significant vasodilator activity in the pulmonary and systemic vascular beds in the rat. Responses to GTN were attenuated by cyanamide, but not allopurinol, whereas responses to nitrite formed by the metabolism of GTN were attenuated by allopurinol and cyanamide. The results with allopurinol and cyanamide suggest that only mitochondrial aldehyde dehydrogenase is involved in the bioactivation of GTN, sodium nitrite, and GSNO, whereas both pathways are involved in the bioactivation of nitrite anion in the intact rat. The comparison of vasodilator activity indicates that GSNO and GTN are more than 1000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures in the rat. Following administration of 1H-[1,2,4]-oxadizaolo[4,3-]quinoxaline-1-one (ODQ), responses to GTN were significantly attenuated, indicating that responses are mediated by the activation of soluble guanylyl cyclase. These data suggest that the reduction of nitrite to nitric oxide formed from the metabolism of GTN, cannot account for the vasodilator activity of GTN in the intact rat and that another mechanism; perhaps the formation of an S-NO, may mediate the vasodilator response to GTN in this species.

  15. Mechanism of nitrite oxidation by eosinophil peroxidase: implications for oxidant production and nitration by eosinophils.

    Science.gov (United States)

    van Dalen, Christine J; Winterbourn, Christine C; Kettle, Anthony J

    2006-03-15

    Eosinophil peroxidase is a haem enzyme of eosinophils that is implicated in oxidative tissue injury in asthma. It uses hydrogen peroxide to oxidize thiocyanate and bromide to their respective hypohalous acids. Nitrite is also a substrate for eosinophil peroxidase. We have investigated the mechanisms by which the enzyme oxidizes nitrite. Nitrite was very effective at inhibiting hypothiocyanous acid ('cyanosulphenic acid') and hypobromous acid production. Spectral studies showed that nitrite reduced the enzyme to its compound II form, which is a redox intermediate containing Fe(IV) in the haem active site. Compound II does not oxidize thiocyanate or bromide. These results demonstrate that nitrite is readily oxidized by compound I, which contains Fe(V) at the active site. However, it reacts more slowly with compound II. The observed rate constant for reduction of compound II by nitrite was determined to be 5.6x10(3) M(-1) x s(-1). Eosinophils were at least 4-fold more effective at promoting nitration of a heptapeptide than neutrophils. This result is explained by our finding that nitrite reacts 10-fold faster with compound II of eosinophil peroxidase than with the analogous redox intermediate of myeloperoxidase. Nitration by eosinophils was increased 3-fold by superoxide dismutase, which indicates that superoxide interferes with nitration. We propose that at sites of eosinophilic inflammation, low concentrations of nitrite will retard oxidant production by eosinophil peroxidase, whereas at higher concentrations nitrogen dioxide will be a major oxidant formed by these cells. The efficiency of protein nitration will be decreased by the diffusion-controlled reaction of superoxide with nitrogen dioxide.

  16. Expanded metabolic versatility of ubiquitous nitrite-oxidizing bacteria from the genus Nitrospira

    OpenAIRE

    Koch, Hanna; Lücker, Sebastian; Albertsen, Mads; Kitzinger, Katharina; Herbold, Craig; Spieck, Eva; Nielsen, Per Halkjaer; Wagner, Michael; Daims, Holger

    2015-01-01

    Nitrification, the sequential aerobic oxidation of ammonia via nitrite to nitrate, is a key process of the biogeochemical nitrogen cycle and catalyzed by two aerobic microbial guilds (nitrifiers): ammonia oxidizers and nitrite-oxidizing bacteria (NOB). NOB are generally considered as metabolically restricted and dependent on ammonia oxidizers. Here, we report that, surprisingly, key NOB of many ecosystems (Nitrospira) convert urea, an important ammonia source in nature, to ammonia and CO2. Th...

  17. Color compensation in nitrite-reduced meat batters incorporating paprika or tomato paste.

    Science.gov (United States)

    Bázan-Lugo, Eduardo; García-Martínez, Ignacio; Alfaro-Rodríguez, Rosa Hayde; Totosaus, Alfonso

    2012-06-01

    Nitrite is a key ingredient the manufacture of meat products, forming a stable pink color characteristic of cured products, retarding the development of rancidity and off-odors and flavors during storage, and preventing microbial growth. The negative aspects of nitrite and the demands for healthy foods result in the need to reduce nitrite in cured meat products. Paprika or tomato has been employed as natural pigments in meat products. The objective of this work was to determine the effect of incorporating paprika powder or tomato paste on the texture, rancidity and instrumental and sensory color compensation in nitrite-reduced meat batters. Addition of tomato paste improved moisture content, resulting in harder but less cohesive samples as compared to control and paprika-containing meat batters. Color characteristics of reduced nitrite samples obtained higher a* red coloration (8.9 for paprika and 7.7-8.0 for tomato paste), as compared to control samples (5.65). Instrumental color was low in control samples, with high values for tomato paste and paprika samples. Nonetheless, tomato paste used to compensate color in nitrite-reduced meat batters was ranked closer to the control sample in sensory evaluation. Color characteristics-instrumental and sensory-in these kinds of meat products were enhanced by the addition of 2.5-3.0% of tomato paste, presenting results close to the non-reduced nitrite control. Similarly, antioxidant components of tomato paste or paprika reduced lipid oxidation. Nitrite reduction from 150 to 100 ppm could be achieved employing tomato paste as a natural pigment to improve color and texture. Copyright © 2011 Society of Chemical Industry.

  18. Conversion of nitrite to nitric oxide at zinc via S-nitrosothiols.

    Science.gov (United States)

    Cardenas, Allan Jay P; Abelman, Rebecca; Warren, Timothy H

    2014-01-07

    Nitrite is an important reservoir of nitric oxide activity in the plasma and cells. Using a biomimetic model, we demonstrate the conversion of zinc-bound nitrite in the tris(pyrazolyl)borate complex (iPr2)TpZn(NO2) to the corresponding S-nitrosothiol RSNO and zinc thiolate (iPr2)TpZn-SR via reaction with thiols H-SR. Decomposition of the S-nitrosothiol formed releases nitric oxide gas.

  19. Effect of Nitrite/Nitrate concentrations on Corrosivity of Washed Precipitate

    Energy Technology Data Exchange (ETDEWEB)

    Congdon, J.W.

    2001-03-28

    Cyclic polarization scans were performed using A-537 carbon steel in simulated washed precipitate solutions of various nitrite and nitrate concentrations. The results of this study indicate that nitrate is an aggressive anion in washed precipitate. Furthermore, a quantitative linear log-log relationship between the minimum effective nitrite concentration and the nitrate concentration was established for washed precipitate with other ions at their average compositions.

  20. ASPECTS CONCERNING NITRATE AND NITRITE POLLUTION OF GROUNDWATERS

    Directory of Open Access Journals (Sweden)

    A. UNGUREANU

    2011-03-01

    Full Text Available Aspects concerning nitrate and nitrite pollution of groundwaters. Water is a basic natural resource for the good functioning of all thebiological processes in nature. It is very important for life and for the developmentof human activities. The quality of the ground water has begun to degrade moreand more, as a result of the physical, chemical and bacteriological changes.Nitrogen compounds pollution of the underground has increased lately. This hasbeen caused by the excessive and irrational use of nitrogen derived fertilizers, bythe wrong storage of the dejections resulted from zootechnical processes and byother chemical substances discharged into water. Samples were collected fromdifferent wells in order to check whether the well water was drinkable. The resultof the test revealed the existence of high concentrations of nitrates as well asvalues exceeding normal microbiological parameters. The value recorded in thetown of Segarcea, the county of Dolj, showed extremely high concentrations ofnitrates of the drinking water in the wells. Thus, Segarcea is the town with thegreatest number of contaminated wells in the country.

  1. Nitrite attenuated peroxynitrite and hypochlorite generation in activated neutrophils.

    Science.gov (United States)

    Ren, Xiaoming; Ding, Yun; Lu, Naihao

    2016-03-15

    Oxidative stress is usually considered as an important factor to the pathogenesis of various diseases. Peroxynitrite (ONOO(-)) and hypochlorite (OCl(-)) are formed in immune cells as a part of the innate host defense system, but excessive reactive oxygen species generation can cause progressive inflammation and tissue damage. It has been proven that through mediating nitric oxide (NO) homeostasis, inorganic nitrite (NO2(-)) shows organ-protective effects on oxidative stress and inflammation. However, the effects of NO2(-) on the function of immune cells were still not clear. The potential role of NO2(-) in modulating ONOO(-) and OCl(-) generation in neutrophil cells was investigated in this study. As an immune cell activator, lipopolysaccharide (LPS) increased both ONOO(-) and OCl(-) production in neutrophils, which was significantly attenuated by NO2(-). NO2(-) reduced superoxide (O2(·-)) generation via a NO-dependent mechanism and increased NO formation in activated neutrophils, suggesting a crucial role of O2(·-) in NO2(-)-mediated reduction of ONOO(-). Moreover, the reduced effect of NO2(-) on OCl(-) production was attributed to that NO2(-) reduced H2O2 production in activated neutrophils without influencing the release of myeloperoxidase (MPO), thus limiting OCl(-) production by MPO/H2O2 system. Therefore, NO2(-) attenuates ONOO(-) and OCl(-) formation in activated neutrophils, opening a new direction to modulate the inflammatory response.

  2. Structure and antioxidant activity of soy protein isolate-dextran conjugates obtained by TiO2 photocatalysis.

    Science.gov (United States)

    Jin, Bei; Zhou, Xiaosong; Li, Bing; Chen, Caiyan; Zhang, Xiaosa; Chen, Siqiao

    2015-01-01

    The aim of this study was to investigate the structural characteristics and antioxidant activities of soy protein isolate- (SPI-) dextran conjugates obtained by TiO2 photocatalysis treatment. Results revealed that the UV-vis absorption and the fluorescence intensity increased as the photocatalytic power increased (P photocatalysis. Moreover, significant changes of secondary structure occurred in SPI-dextran conjugates. The α-helix, β-sheet, β-turns, and random coil were changed from approximately 10.6%, 37.9%, 12.9%, and 38.6% to 3.8%, 10.4%, 17.7%, and 68.8%, respectively, after treatment at photocatalytic power of 1000 W. In addition, SPI-dextran conjugates obtained by TiO2 photocatalysis treatment exhibited high hydroxyl radical scavenging activity and possessed increased reducing power. All data indicated that TiO2 photocatalysis was an efficient method for promoting protein-polysaccharide copolymerisation.

  3. Use of gamma radiation on control of Clostridium botulinum in mortadella formulated with different nitrite levels

    Science.gov (United States)

    Dutra, Monalisa Pereira; Aleixo, Glécia de Cássia; Ramos, Alcinéia de Lemos Souza; Silva, Maurício Henriques Louzada; Pereira, Marcio Tadeu; Piccoli, Roberta Hilsdorf; Ramos, Eduardo Mendes

    2016-02-01

    This study investigated the effects of applying different doses of gamma radiation (0, 10 and 20 kGy) on Clostridium botulinum spores (107 spores/g) inoculated into mortadellas with different nitrite contents (0, 150 and 300 ppm). We also evaluated the order of application of heat (cooking) and irradiation processing. The products were evaluated for survival of C. botulinum, pH, water activity (Aw), redox potential (Eh) and residual nitrite content. In the non-irradiated raw batters, almost all spores could be recovered when no nitrite was added and only half was recovered with the addition of 150 ppm of nitrite. The use of 150 ppm of nitrite was able to inhibit the germination or growth of C. botulinum in non-irradiated cooked mortadellas after 48 h of processing. However, after 30 days of chilling storage (4 °C), it was possible to recover 105 UFC/g of this microorganism. The gamma irradiation (>10 kGy) had a positive effect on the inactivation of C. botulinum in mortadellas, independent of the sodium nitrite level used and the cooking/irradiation processing order.

  4. Effect of dissolved oxygen concentration on nitrite accumulation in nitrifying sequencing batch reactor.

    Science.gov (United States)

    Sánchez, Omar; Bernet, Nicolas; Delgenès, Jean-Philippe

    2007-08-01

    A mathematical model based on Activated Sludge Model No. 3 (International Water Association, London) and laboratory-scale experiments were used to investigate ammonia conversion by nitrification in a sequencing batch reactor (SBR). The purpose of the study was to assess the effect of dissolved oxygen concentration on nitrite accumulation in the SBR. As the dissolved oxygen concentration in the SBR depends on the balance between oxygen consumption and oxygen transfer rates, ammonium conversion was measured for different air flowrate values to obtain different dissolved oxygen concentration profiles during the cycle. The ammonia concentration in the feeding medium was 500 mg ammonium as nitrogen (N-NH4(+))/L, and the maximum nitrite concentration achieved during a cycle was approximately 50 mg nitrite as nitrogen (N-NO2)/L. The air flow supplied to the reactor was identified as a suitable parameter to control nitrite accumulation in the SBR. This identification was carried out based on experimental results and simulation with a calibrated model. At a low value of the volumetric mass-transfer coefficient (kLa), the maximum nitrite concentration achieved during a cycle depends strongly on k(L)a, whereas, at a high value of k(L)a, the maximum nitrite concentration was practically independent of kL(a).

  5. Optimization of fermentation media for nitrite oxidizing bacteria using sequential statistical design.

    Science.gov (United States)

    Ren, Jie; Lin, Wei-Tie; Shen, Yan-Jing; Wang, Ju-Fang; Luo, Xiao-Chun; Xie, Ming-Quan

    2008-11-01

    The sequential statistical experimental design (Plackett-Burman, factorial, response surface and steepest ascent experiment) was applied to optimize the culture medium of nitrite oxidizing bacteria for improving the nitrite oxidizing rate. Estimated optimum medium composition of the nitrite oxidizing rate was as follows: NaHCO3, 1.86gl(-1); NaNO2, 2.04gl(-1); Na2CO3, 0.2gl(-1); NaCl, 0.2gl(-1); KH2PO4, 0.1gl(-1); MgSO4 x7H2O, 0.1gl(-1); and FeSO4 x 7H2O, 0.01gl(-1). The nitrite oxidizing rate was increased by 48.0% and reached a maximum at 859.5+/-8.4mgNO2-N/gMLSS.d as compared to 580.7+/-25.8mgNO2-N/gMLSS x d. In the field trial, 50L of nitrite oxidizing bacteria concentrate (1.99gVSS/L) with 850mgNO2-N/gMLSS x d were added to 0.6ha of the aquaculture water. Nitrite level in all treated ponds remained very low compared to the steady increase observed in all of the control ponds during 7 days.

  6. A Family Clustered Nitrite Intoxication Investigation in Gaoxin District, Suzhou, China, 2013.

    Directory of Open Access Journals (Sweden)

    Ruiping Wang

    2013-12-01

    Full Text Available In April, 2013, a Suzhou Hospital reported a nitrite intoxication patient in coma as well as 2 family members with the similar symptom 5 days ahead. We investigated the event to identify the cause, source and possible pollution ways of the contamination.We defined case as any person living in YSHY community who has cyanosis and with at least one of the following symptoms: dizziness, headache, fatigue, tachycardia, drowsiness, nausea, vomiting, abdominal pain or diar-rhea during April 15 to April 25, 2013. We searched for case by interviewing community residents and reviewing clinics' medical records; information was then retrospectively collected on the patient's food history, cooking procedures and food sources.We identified 3 nitrite intoxication cases, 1 male and 2 female from a family. The interval time between dinner and onset was < 1 hour. Retrospective survey showed 'sugar stir and mix asparagus' on April 17 and 'scrambled asparagus' on April 21 were suspected foods. Both suspected dishes had 'sugar' added, sourced from a clean-up of a neighboring rental house. Nitrite was detected in a vomitus sample, the 'sugar' and two leftover food samples.This family clustered nitrite intoxication was induced by using unidentified nitrite as sugar to cook dishes. We recommend sodium nitrite should be dyed with bright colors to avoid mistaking it for plain salt or sugar, health departments strengthen food hygiene propaganda to improve people's recognition of food safety, and to alert them the dangerous of eating unidentified or unknown source food.

  7. Effect of lycopene on serum nitrite-nitrate levels in diabetic rats

    Directory of Open Access Journals (Sweden)

    Sevim Ç Yegin

    2015-01-01

    Full Text Available The effect of lycopene on serum nitrate-nitrite levels was investigated in diabetic rats. In this investigation, 28 Wistar rats were divided into 4 groups, each of seven rats. These groups were control group, diabetes group, diabetes-lycopene group and lycopene group. The concentration of nitrite and nitrate was detected at high levels in diabetes group, diabetes-lycopene group and lycopene group as compared with the control group (P<0.05. Especially, the increase in the levels of nitrate in diabetes group and lycopene group was statistically significant when compared with diabetes-lycopene group and control group (P<0.05. In addition, we also determined the proportion of nitrite/nitrate for nitric oxide radical formation. Therefore, it is important to investigate the recovery and stability of nitrite and nitrate in samples. As a result of this study, it was observed that the amounts of nitrate and nitrite increased due to oxidative stress in diabetes and also application of antioxidant lycopene caused an increase in the amounts of nitrate and nitrite levels.

  8. Enhanced activity and selectivity of carbon nanofiber supported Pd catalysts for nitrite reduction.

    Science.gov (United States)

    Shuai, Danmeng; Choe, Jong Kwon; Shapley, John R; Werth, Charles J

    2012-03-06

    Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). Results show that nitrite reduction activity increases by 3.1-fold and selectivity decreases by 8.0-fold, with decreasing Pd nanoparticle size from 1.4 to 9.6 nm. Both activity and selectivity are not significantly influenced by Pd interior versus exterior CNF loading. Consequently, turnover frequencies (TOFs) among all CNF catalysts are similar, suggesting nitrite reduction is not sensitive to Pd location on CNFs nor Pd structure. CNF-based catalysts compare favorably to conventional Pd catalysts (i.e., Pd on activated carbon or alumina) with respect to nitrite reduction activity and selectivity, and they maintain activity over multiple reduction cycles. Hence, our results suggest new insights that an optimum Pd nanoparticle size on CNFs balances faster kinetics with lower ammonia production, that catalysts can be tailored at the nanoscale to improve catalytic performance for nitrite, and that CNFs hold promise as highly effective catalyst supports in drinking water treatment.

  9. Consistent antioxidant and antihypertensive effects of oral sodium nitrite in DOCA-salt hypertension

    Directory of Open Access Journals (Sweden)

    Jefferson H. Amaral

    2015-08-01

    Full Text Available Hypertension is a common disease that includes oxidative stress as a major feature, and oxidative stress impairs physiological nitric oxide (NO activity promoting cardiovascular pathophysiological mechanisms. While inorganic nitrite and nitrate are now recognized as relevant sources of NO after their bioactivation by enzymatic and non-enzymatic pathways, thus lowering blood pressure, mounting evidence suggests that sodium nitrite also exerts antioxidant effects. Here we show for the first time that sodium nitrite exerts consistent systemic and vascular antioxidant and antihypertensive effects in the deoxycorticosterone-salt (DOCA-salt hypertension model. This is particularly important because increased oxidative stress plays a major role in the DOCA-salt hypertension model, which is less dependent on activation of the renin-angiotensin system than other hypertension models. Indeed, antihypertensive effects of oral nitrite were associated with increased plasma nitrite and nitrate concentrations, and completely blunted hypertension-induced increases in plasma 8-isoprostane and lipid peroxide levels, in vascular reactive oxygen species, in vascular NADPH oxidase activity, and in vascular xanthine oxidoreductase activity. Together, these findings provide evidence that the oral administration of sodium nitrite consistently decreases the blood pressure in association with major antioxidant effects in experimental hypertension.

  10. Numerical modeling of nitrogen removal processes in biofilters with simultaneous nitritation and anammox.

    Science.gov (United States)

    Shi, Shun; Tao, Wendong

    2013-01-01

    This study developed a simple numerical model for nitrogen removal in biofilters, which was designed to enhance simultaneous nitritation and anaerobic ammonium oxidation (anammox). It is the first attempt to simulate anammox together with two-step nitrification in natural treatment systems, which may have different kinetic parameters and temperature effects from conventional bioreactors. Prediction accuracy was improved by adjusting kinetic coefficients over the startup period of the biofilters. The maximum rates of nitritation and nitrite oxidation increased linearly over time during the startup period. Simulations confirmed successful enhancement of simultaneous nitritation and anammox (SNA) in the biofilters, with anammox contributing 35% of ammonium removal. Effluent ammonium concentration was affected by influent ammonium concentration and the maximum nitritation rate, and was insensitive to the maximum nitrite oxidation rate and anammox substrate factor. Ammonium removal via SNA was likely limited by biomass of aerobic ammonia oxidizing bacteria in the biofilters. The developed model is a promising tool for studying the dynamics of nitrogen removal processes including SNA in natural treatment systems.

  11. A family cluster of nitrite poisoning, Suzhou City, Jiangsu Province, China, 2013

    Directory of Open Access Journals (Sweden)

    Ruiping Wang

    2013-07-01

    Full Text Available Background: In April 2013, a hospital in Suzhou City notified authorities of a patient with nitrite poisoning with two other family members who had similar toxic symptoms five days prior. We investigated the event to identify the cause, source and possible route of contamination. Methods: A case was defined as any person living in the Yang Shan Hua Yuan community who had been diagnosed with cyanoderma and food poisoning symptoms from 15 to 25 April 2013. Active case finding was conducted by interviewing community residents and reviewing medical records from local clinics; information was then retrospectively collected on the patient’s food history, cooking procedures and food sources. Results: We identified three nitrite poisoning cases, one male and two females, from the same family. The time between dinner and onset of illness was less than an a hour. A retrospective survey showed that a substance presumed to be sugar mixed with asparagus on 17 April and with stir-fried asparagus on 21 April wasthe suspected contaminant. The presumed sugar came from a clean-up of a neighbouring rental house. Nitrite was detected in a vomitus sample, the sugar substance and two leftover food samples. Conclusion: This family cluster of nitrite poisoning resulted from the mistaken use of nitrite as sugar to cook dishes. We recommend that sodium nitrite be dyed a bright colour to prevent such a mistake and that health departments strengthen food hygiene education to alert people about the danger of eating unidentified food from an unknown source.

  12. Production of cured meat color in nitrite-free Harbin red sausage by Lactobacillus fermentum fermentation.

    Science.gov (United States)

    Zhang, Xue; Kong, Baohua; Xiong, Youling L

    2007-12-01

    Lactobacillus fermentum was substituted for nitrite to produce cured pink color in a Chinese-style sausage. Treatments included inoculations (10(4), 10(6), and 10(8)CFU/g meat) followed by fermentation at 30°C for 8h and then at 4°C for 16h. Control sausage (with sodium nitrite, 60mg/kg meat) was cured at 4°C for 24h without L. fermentum. The UV-Vis spectra of pigment extract from L. fermentum-treated sausage were identical to that of nitrosylmyoglobin (NO-Mb) formed in nitrite-treated control. The NO-Mb concentration and the colorimetric a(∗) value of sausage treated with 10(8)CFU/g meat of L. fermentum essentially replicated those in nitrite-cured meat. Free amino acid content in sausage treated with L. fermentum was greater and the pH slightly lower compared with the nitrite-cured control sample. This study showed that L. fermentum has the potential to substitute for nitrite in the sausage production.

  13. Spectrophotometric determination of nitrite in soil and water using cefixime and central composite design

    Science.gov (United States)

    Shariati-Rad, Masoud; Irandoust, Mohsen; Mohammadi, Shabnam

    2015-10-01

    The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360 nm which Beer's Law is obeyed over the concentration range 0.02-15.00 mg L-1 of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3 × 10-3 mg L-1 was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1 × 103 (L mol-1 cm-1) and lower than 10%, respectively.

  14. Therapeutic effects of inorganic nitrate and nitrite in cardiovascular and metabolic diseases.

    Science.gov (United States)

    Omar, S A; Webb, A J; Lundberg, J O; Weitzberg, E

    2016-04-01

    Nitric oxide (NO) is generated endogenously by NO synthases to regulate a number of physiological processes including cardiovascular and metabolic functions. A decrease in the production and bioavailability of NO is a hallmark of many major chronic diseases including hypertension, ischaemia-reperfusion injury, atherosclerosis and diabetes. This NO deficiency is mainly caused by dysfunctional NO synthases and increased scavenging of NO by the formation of reactive oxygen species. Inorganic nitrate and nitrite are emerging as substrates for in vivo NO synthase-independent formation of NO bioactivity. These anions are oxidation products of endogenous NO generation and are also present in the diet, with green leafy vegetables having a high nitrate content. The effects of nitrate and nitrite are diverse and include vasodilatation, improved endothelial function, enhanced mitochondrial efficiency and reduced generation of reactive oxygen species. Administration of nitrate or nitrite in animal models of cardiovascular disease shows promising results, and clinical trials are currently ongoing to investigate the therapeutic potential of nitrate and nitrite in hypertension, pulmonary hypertension, peripheral artery disease and myocardial infarction. In addition, the nutritional aspects of the nitrate-nitrite-NO pathway are interesting as diets suggested to protect against cardiovascular disease, such as the Mediterranean diet, are especially high in nitrate. Here, we discuss the potential therapeutic opportunities for nitrate and nitrite in prevention and treatment of cardiovascular and metabolic diseases.

  15. Enhanced Activity and Selectivity of Carbon Nanofiber Supported Pd Catalysts for Nitrite Reduction

    KAUST Repository

    Shuai, Danmeng

    2012-03-06

    Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). Results show that nitrite reduction activity increases by 3.1-fold and selectivity decreases by 8.0-fold, with decreasing Pd nanoparticle size from 1.4 to 9.6 nm. Both activity and selectivity are not significantly influenced by Pd interior versus exterior CNF loading. Consequently, turnover frequencies (TOFs) among all CNF catalysts are similar, suggesting nitrite reduction is not sensitive to Pd location on CNFs nor Pd structure. CNF-based catalysts compare favorably to conventional Pd catalysts (i.e., Pd on activated carbon or alumina) with respect to nitrite reduction activity and selectivity, and they maintain activity over multiple reduction cycles. Hence, our results suggest new insights that an optimum Pd nanoparticle size on CNFs balances faster kinetics with lower ammonia production, that catalysts can be tailored at the nanoscale to improve catalytic performance for nitrite, and that CNFs hold promise as highly effective catalyst supports in drinking water treatment. © 2012 American Chemical Society.

  16. Reactions of ferrous neuroglobin and cytoglobin with nitrite under anaerobic conditions

    DEFF Research Database (Denmark)

    Petersen, Morten Gjerning; Dewilde, Sylvia; Fago, Angela

    2008-01-01

    Recent evidence suggests that the reaction of nitrite with deoxygenated hemoglobin and myoglobin contributes to the generation of nitric oxide and S-nitrosothiols in vivo under conditions of low oxygen availability. We have investigated whether ferrous neuroglobin and cytoglobin, the two hexacoor......Recent evidence suggests that the reaction of nitrite with deoxygenated hemoglobin and myoglobin contributes to the generation of nitric oxide and S-nitrosothiols in vivo under conditions of low oxygen availability. We have investigated whether ferrous neuroglobin and cytoglobin, the two...... hexacoordinate globins from vertebrates expressed in brain and in a variety of tissues, respectively, also react with nitrite under anaerobic conditions. Using absorption spectroscopy, we find that ferrous neuroglobin and nitrite react with a second-order rate constant similar to that of myoglobin, whereas...... the ferrous heme of cytoglobin does not react with nitrite. Deconvolution of absorbance spectra shows that, in the course of the reaction of neuroglobin with nitrite, ferric Fe(III) heme is generated in excess of nitrosyl Fe(II)-NO heme as due to the low affinity of ferrous neuroglobin for nitric oxide...

  17. Energetic Consequences of nitrite stress in Desulfovibrio vulgarisHildenborough, inferred from global transcriptional analysis

    Energy Technology Data Exchange (ETDEWEB)

    He, Qiang; Huang, Katherine H.; He, Zhili; Alm, Eric J.; Fields,Matthew W.; Hazen, Terry C.; Arkin, Adam P.; Wall, Judy D.; Zhou, Jizhong

    2005-11-03

    Many of the proteins that are candidates for bioenergetic pathways involved with sulfate respiration in Desulfovibrio spp. have been studied, but complete pathways and overall cell physiology remain to be resolved for many environmentally relevant conditions. In order to understand the metabolism of these microorganisms under adverse environmental conditions for improved bioremediation efforts, Desulfovibrio vulgaris Hildenborough was used as a model organism to study stress response to nitrite, an important intermediate in the nitrogen cycle. Previous physiological studies demonstrated that growth was inhibited by nitrite and that nitrite reduction was observed to be the primary mechanism of detoxification. Global transcriptional profiling with whole-genome microarrays revealed coordinated cascades of responses to nitrite in pathways of energy metabolism, nitrogen metabolism, oxidative stress response, and iron homeostasis. In agreement with previous observations, nitrite-stressed cells showed a decrease in the expression of genes encoding sulfate reduction functions in addition to respiratory oxidative phosphorylation and ATP synthase activity. Consequently, the stressed cells had decreased expression of the genes encoding ATP-dependent amino acid transporters and proteins involved in translation. Other genes up-regulated in response to nitrite include the genes in the Fur regulon, which is suggested to be involved in iron homeostasis, and genes in the Per regulon, which is predicted to be responsible for oxidative stress response.

  18. Performance and microbial ecology of a nitritation sequencing batch reactor treating high-strength ammonia wastewater

    Science.gov (United States)

    Chen, Wenjing; Dai, Xiaohu; Cao, Dawen; Wang, Sha; Hu, Xiaona; Liu, Wenru; Yang, Dianhai

    2016-01-01

    The partial nitrification (PN) performance and the microbial community variations were evaluated in a sequencing batch reactor (SBR) for 172 days, with the stepwise elevation of ammonium concentration. Free ammonia (FA) and low dissolved oxygen inhibition of nitrite-oxidized bacteria (NOB) were used to achieve nitritation in the SBR. During the 172 days operation, the nitrogen loading rate of the SBR was finally raised to 3.6 kg N/m3/d corresponding the influent ammonium of 1500 mg/L, with the ammonium removal efficiency and nitrite accumulation rate were 94.12% and 83.54%, respectively, indicating that the syntrophic inhibition of FA and low dissolved oxygen contributed substantially to the stable nitrite accumulation. The results of the 16S rRNA high-throughput sequencing revealed that Nitrospira, the only nitrite-oxidizing bacteria in the system, were successively inhibited and eliminated, and the SBR reactor was dominated finally by Nitrosomonas, the ammonium-oxidizing bacteria, which had a relative abundance of 83%, indicating that the Nitrosomonas played the primary roles on the establishment and maintaining of nitritation. Followed by Nitrosomonas, Anaerolineae (7.02%) and Saprospira (1.86%) were the other mainly genera in the biomass. PMID:27762325

  19. Ficoll and dextran vs. globular proteins as probes for testing glomerular permselectivity: effects of molecular size, shape, charge, and deformability.

    Science.gov (United States)

    Venturoli, Daniele; Rippe, Bengt

    2005-04-01

    Polydisperse mixtures of dextran or Ficoll have been frequently used as molecular probes for studies of glomerular permselectivity because they are largely inert and not processed (reabsorbed) by the proximal tubules. However, dextrans are linear, flexible molecules, which apparently are hyperpermeable across the glomerular barrier. By contrast, the Ficoll molecule is almost spherical. Still, there is ample evidence that Ficoll fractional clearances (sieving coefficients) across the glomerular capillary wall (GCW) are markedly higher than those for neutral globular proteins of an equivalent in vitro Stokes-Einstein (SE) radius. Physical data, obtained by "crowding" experiments or measurements of intrinsic viscosity, suggest that the Ficoll molecule exhibits a rather open, deformable structure and thus deviates from an ideally hard sphere. This is also indicated from the relationship between (log) in vitro SE radius and (log) molecular weight (MW). Whereas globular proteins seem to behave in a way similar to hydrated hard spheres, polydisperse dextran and Ficoll exhibit in vitro SE radii that are much larger than those for compact spherical molecules of equivalent MW. For dextran, this can be partially explained by a high-molecular-size asymmetry. However, for Ficoll the explanation may be that the Ficoll molecule is more flexible (deformable) than are globular proteins. An increased compressibility of Ficoll and an increased deformability and size asymmetry for dextran may be the explanation for the fact that the permeability of the GCW is significantly higher when assessed using polysaccharides such as Ficoll or dextran compared with that obtained using globular proteins as molecular size probes. We suggest that molecular deformability, besides molecular size, shape, and charge, plays a crucial role in determining the glomerular permeability to molecules of different species.

  20. The Effects of Physicochemical Factors and Cell Density on Nitrite Transformation in a Lipid-Rich Chlorella.

    Science.gov (United States)

    Liang, Fang; Du, Kui; Wen, Xiaobin; Luo, Liming; Geng, Yahong; Li, Yeguang

    2015-12-28

    To understand the effects of physicochemical factors on nitrite transformation by microalgae, a lipid-rich Chlorella with high nitrite tolerance was cultured with 8 mmol/l sodium nitrite as sole nitrogen source under different conditions. The results showed that nitrite transformation was mainly dependent on the metabolic activities of algal cells rather than oxidation of nitrite by dissolved oxygen. Light intensity, temperature, pH, NaHCO3 concentrations, and initial cell densities had significant effects on the rate of nitrite transformation. Single-factor experiments revealed that the optimum conditions for nitrite transformation were light intensity: 300 μmol/m(2); temperature: 30°C; pH: 7-8; NaHCO3 concentration: 2.0 g/l; and initial cell density: 0.15 g/l; and the highest nitrite transformation rate of 1.36 mmol/l/d was achieved. There was a positive correlation between nitrite transformation rate and the growth of Chlorella. The relationship between nitrite transformation rate (mg/l/d) and biomass productivity (g/l/d) could be described by the regression equation y = 61.3x (R(2) = 0.9665), meaning that 61.3 mg N element was assimilated by 1.0 g dry biomass on average, which indicated that the nitrite transformation is a process of consuming nitrite as nitrogen source by Chlorella. The results demonstrated that the Chlorella suspension was able to assimilate nitrite efficiently, which implied the feasibility of using flue gas for mass production of Chlorella without preliminary removal of NOX.

  1. Involvement of lymphocytes in dextran sulfate sodium-induced experimental colitis

    Institute of Scientific and Technical Information of China (English)

    Tae Woon Kim; Jae Nam Seo; Young Ho Suh; Hyo Jin Park; Ju Hyun Kim; Ji Young Kim; Kwon Tk Oh

    2006-01-01

    AIM: To investigate the roles of lymphocytes in the development of dextran sulfate sodium-induced colitis.METHODS: Using various doses of dextran sulfate sodium (DSS), we induced colitis in wild-type B6control and Rag-1 knockout (H-2b haplotype) mice,and evaluated the colitis in terms of symptomatic and histologic parameters, such as weight loss, survival,severity of diarrhea, shortage of colon length and histological changes. Symptomatic parameters were checked daily and histological changes were scored.RESULTS: Although development of colitis in Rag-1knockout mice treated with high dose (5%) of DSS was comparable to that in B6 control mice, colitis progression was much more tolerable in Rag-1 knockout mice compared to than in B6 mice treated with low dose (1.5%)DSS. Symptomatic parameters as well as histopathologic changes were improved in Rag-1 knockout mice.CONCLUSION: These results indicate that the presence of lymphocytes contributes to colitis progression at low dose of DSS stimulation. Lymphocytes may play roles as an aggravating factor in DSS-induced colitis.

  2. Synthesis, Characterization, and Toxicity Evaluation of Dextran-Coated Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mihaela Balas

    2017-02-01

    Full Text Available We report the synthesis of dextran-coated iron oxide magnetic nanoparticles (DIO-NPs with spherical shape and uniform size distribution as well as their accumulation and toxic effects on Jurkat cells up to 72 h. The characterization of dextran-coated maghemite nanoparticles was done by X-ray diffraction and dynamic light scattering analyses, transmission electron microscopy imaging, attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, magnetic hysteresis, and relaxometry measurements. The quantification of DIO-NPs intracellular uptake showed a progressive accumulation of iron as a function of time and dose accompanied by additional lysosome formation and an increasing darkening exhibited by a magnetic resonance imaging (MRI scanner. The cytotoxicity assays revealed a decrease of cell viability and a loss of membrane integrity in a time- and dose-dependent manner. Exposure to DIO-NPs determined an increase in reactive oxygen species level up to 72 h. In the first two days of exposure, the level of reduced glutathione decreased and the amount of malondyaldehyde increased, but at the end of the experiment, their concentrations returned to control values. These nanoparticles could be used as contrast agents for MRI but several parameters concerning their interaction with the cells should be taken into consideration for a safe utilization.

  3. Effectiveness of composition based on oxidized dextran in the treatment of grade IIIB skin burns.

    Science.gov (United States)

    Shkurupy, V A; Karpov, M A; Troitskii, A V; Arkhipov, S A; Neshchadim, D V

    2015-03-01

    Grade IIIB skin burns were treated with a composition based on oxidized dextran with a molecular weight of 40 kDa (oxidation of 7% glucose residues). On day 32 after burn infliction and from the start of the treatment, the area of skin defect in rats was 30% less than in the group without treatment and by 2.3 times less than in rats treated with panthenol. In rats treated with dextran-based composition or panthenol, the eschar was absent on day 21 after the start of the treatment; by day 32, we found cells of surface epithelium, hair follicles, and sebaceous glands above the scar tissue that were absent in untreated animals; in rats treated with the composition, their number was higher by 2.5 times than in animals treated with panthenol. Treatment with the composition increased volume density (by 2.5 times) and numerical density (by more than 3 times) of blood vessels in the wound and reduced signs of inflammation and fibroplastic activity of fibroblasts in comparison with the corresponding parameters in untreated animals or animals treated with panthenol.

  4. One-pot synthesis of dextran decorated reduced graphene oxide nanoparticles for targeted photo-chemotherapy.

    Science.gov (United States)

    Hu, Yanfang; He, Liang; Ding, Jianxun; Sun, Diankui; Chen, Li; Chen, Xuesi

    2016-06-25

    Graphene-based nanocarriers show great potential in photo-chemotherapy, however, to prepare desired reduced graphene oxide (rGO) nanoparticles in a facile way is still a challenge. Herein, a novel strategy has been presented to prepare rGO nanoparticle using dextran (Dex) as a reducing agent. In this strategy, Dex was directly conjugated on rGO by hydrogen bond and then self-assemble to form rGO/Dex nanoparticles. After decorated by dextran, rGO-based nanoparticles not only show excellent biocompatibility but also can load anticancer drug for photo-chemotherapy. The data of fourier transform infrared (FT-IR) analysis, Raman spectrum analysis, thermos-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), the transmission electron microscope (TEM) image and dynamic light scattering (DLS) measurements powerfully proved that the stable rGO-based nanoparticles with desired nanosize have been successfully prepared. To verify the photo-chemotherapy, anticancer drug, doxorubicin (DOX), has been loaded on rGO/Dex nanoparticles (rGO/DOX/Dex). And RGD, a kind of oligopeptide which can improve the intracellular uptake by αvβ3 recognition, also has been introduced (rGO/DOX/RDex). Compared with single chemotherapy, rGO/DOX/Dex and rGO/DOX/RDex combining the local specific chemotherapy and external near-infrared (NIR) photo-thermal therapy show higher therapeutic efficacy, endowing the desired rGO-based nanoparticle with great potential for cancer treatments.

  5. Silane-dextran chemistry on lateral flow polymer chips for immunoassays.

    Science.gov (United States)

    Jönsson, Christina; Aronsson, Magnus; Rundström, Gerd; Pettersson, Christer; Mendel-Hartvig, Ib; Bakker, Jimmy; Martinsson, Erik; Liedberg, Bo; MacCraith, Brian; Ohman, Ove; Melin, Jonas

    2008-07-01

    The prognosis for patients suffering from cardiovascular and many other diseases can be substantially improved if diagnosed at an early stage. High performance diagnostic testing using disposable microfluidic chips can provide a platform for realizing this vision. Amic AB (Uppsala, Sweden) has developed a new microfluidic test chip for sandwich immunoassays fabricated by injection molding of the cycloolefin-copolymer Zeonor. A highly ordered array of micropillars within the fluidic chip distributes the sample solution by capillary action. Since wetting of the pillar array surface is the only driving force for liquid distribution precise control of the surface chemistry is crucial. In this work we demonstrate a novel protocol for surface hydrophilization and antibody immobilization on cycloolefin-copolymer test chips, based on direct silanisation of the thermoplastic substrate. Dextran is subsequently covalently coupled to amino groups, thus providing a coating with a low contact angle suitable for antibody immobilization. The contact angle of dextran coated chips is stable for at least two months, which enables production of large batches that can be stored for extended periods of time. We demonstrate the utility of the presented platform and surface chemistry in a C-reactive protein assay with a detection limit of 2.6 ng ml(-1), a dynamic range of 10(2) and a coefficient of variance of 15%.

  6. Persistent post-dural-puncture headache treated with epidural infusion of dextran.

    Science.gov (United States)

    Aldrete, J A

    1994-05-01

    A retrospective review was done on medical records of 13 patients with persistent post-dural-puncture headaches after one or more epidural blood patches. Headache occurred in nine patients with post-laminectomy syndrome after "wet taps" while performing epidural blocks. In two patients post-dural-puncture headache appeared after long term implanted intrathecal catheters were removed. In two other cases headache developed after spinal anesthesia. Treatment included bed rest, intravenous hydration and at least one epidural blood patch; three patients were given 60 milliliters of epidural saline, without success. Eight epidural catheters were inserted through the lumbar access and five through the caudal approach. Initially, a bolus of 20 milliliters of dextran-40 was given followed by an infusion of 3 mL/hr, until 12 hours after the head pain and any other related symptoms subsided. In all patients the headache disappeared within 20 hours after initiating therapy (9.55 mean hours, SD +/- 0.79). In five patients headache ceased in less than five hours. Nausea and photo-phobia subsided earlier. Patients with post-dural-puncture headache resistant to other treatments, including at least one epidural blood patch, were successfully treated by a bolus followed by continuous epidural infusion of dextran-40.

  7. Characterization of glucansucrase and dextran from Weissella sp. TN610 with potential as safe food additives.

    Science.gov (United States)

    Bejar, Wacim; Gabriel, Valérie; Amari, Myriam; Morel, Sandrine; Mezghani, Monia; Maguin, Emmanuelle; Fontagné-Faucher, Catherine; Bejar, Samir; Chouayekh, Hichem

    2013-01-01

    Pear-derived Weissella sp. TN610 produced extracellular glycosyltransferase activity responsible for the synthesis of soluble exopolysaccharide from sucrose. Acid and dextranase-catalyzed hydrolysis revealed that the synthesized polymer was a glucan. According to (1)H and (13)C NMR analysis, the glucan produced by TN610 was a linear dextran made of 96% α-(1→6) and 4% α-(1→3) linkages. Zymogram analysis confirmed the presence of a unique glucansucrase of approximately 180 kDa in the cell-free supernatant from TN610. The crude enzyme, optimally active at 37°C and pH 5, has promising potential for application as a food additive since it catalyzes dextran synthesis in sucrose-supplemented milk, allowing its solidification. A 4257-bp product corresponding to the mature glucansucrase gene was amplified by PCR from TN610. It encoded a polypeptide of 1418 residues having a calculated molecular mass of 156.089 kDa and exhibiting 96% and 95% identity with glucansucrases from Lactobacillus fermentum Kg3 and Weissella cibaria CMU, respectively.

  8. Inhibited growth of Pseudomonas aeruginosa by dextran- and polyacrylic acid-coated ceria nanoparticles

    Directory of Open Access Journals (Sweden)

    Wang Q

    2013-08-01

    Full Text Available Qi Wang,1 J Manuel Perez,2 Thomas J Webster1,3 1Bioengineering Program, College of Engineering, Northeastern University, Boston, MA, USA; 2Nanoscience Technology Center, University of Central Florida, Orlando, FL, USA; 3Department of Chemical Engineering, College of Engineering, Northeastern University, Boston, MA, USA Abstract: Ceria (CeO2 nanoparticles have been widely studied for numerous applications, but only a few recent studies have investigated their potential applications in medicine. Moreover, there have been almost no studies focusing on their possible antibacterial properties, despite the fact that such nanoparticles may reduce reactive oxygen species. In this study, we coated CeO2 nanoparticles with dextran or polyacrylic acid (PAA because of their enhanced biocompatibility properties, minimized toxicity, and reduced clearance by the immune system. For the first time, the coated CeO2 nanoparticles were tested in bacterial assays involving Pseudomonas aeruginosa, one of the most significant bacteria responsible for infecting numerous medical devices. The results showed that CeO2 nanoparticles with either coating significantly inhibited the growth of Pseudomonas aeruginosa, by up to 55.14%, after 24 hours compared with controls (no particles. The inhibition of bacterial growth was concentration dependent. In summary, this study revealed, for the first time, that the characterized dextran- and PAA-coated CeO2 nanoparticles could be potential novel materials for numerous antibacterial applications. Keywords: antibacterial, biomedical applications

  9. Fabrication of aptamer decorated dextran coated nano-graphene oxide for targeted drug delivery.

    Science.gov (United States)

    Alibolandi, Mona; Mohammadi, Marzieh; Taghdisi, Seyed Mohammad; Ramezani, Mohammad; Abnous, Khalil

    2017-01-02

    In the current study, dextran (DEX) was covalently conjugated to the surface of nano-GO sheets, making stable biocompatible dextran coated GO (GO-DEX). The prepared GO-DEX was nontoxic to 4T1 mammary carcinoma cell line at concentrations up to 300μg/mL. AS1411 aptamer, a ssDNA aptamer which can improve the intracellular uptake by nucleolin recognition, also has been introduced to hydroxyl groups of DEX in GO-DEX to produce GO-DEX-Apt. Moreover, curcumin (CUR), a natural polyphenol, found in the rhizomes of Curcuma longa (turmeric) which shows antineoplastic effects, was loaded onto the GO-DEX and GO-DEX-Apt via π-π stacking interactions with a high loading capacity (∼29wt%). The GO-DEX-Apt-CUR could efficiently enter into 4T1 and MCF-7 nucleolin over-expressed cancer cells confirmed by fluorescence microscope and flowcytometry, and it also showed significantly higher cytotoxicity. These types of targeted nanoscale drug delivery vehicles on the basis of DEX coated GO may find potential application in cancer chemotherapy.

  10. Synthesis, characterization and antimicrobial activity of dextran sulphate stabilized silver nanoparticles

    Science.gov (United States)

    Cakić, Milorad; Glišić, Slobodan; Nikolić, Goran; Nikolić, Goran M.; Cakić, Katarina; Cvetinov, Miroslav

    2016-04-01

    Dextran sulphate stabilized silver nanoparticles (AgNPs - DS) were synthesized from aqueous solution of silver nitrate (AgNO3) and dextran sulphate sodium salt (DS). The characterization of AgNPs - DS was performed by ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and antimicrobial activity. The formation of AgNPs - DS was monitored by colour changes of the reaction mixture from yellowish to brown and by measuring the surface plasmon resonance absorption peak in UV-VIS spectra at 420 nm. The SEM analysis was used for size and shape determination of AgNPs - DS. The presence of elemental silver and its crystalline structure in AgNPs - DS were confirmed by EDX and XRD analyses. The possible functional groups of DS responsible for the reduction and stabilization of AgNPs were determinated by FTIR spectroscopy. The AgNPs - DS showed strong antibacterial activity against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 11778, Bacillus luteus in haus strain, Bacillus subtilis ATTC 6633, Listeria monocytogenes ATCC 15313, Escherichia coli ATTC 25922, Pseudomonas aeruginosa ATTC 27853, Klebsiella pneumoniae ATTC 700603, Proteus vulgaris ATTC 8427, and antifungal activity against Candida albicans ATTC 2091.

  11. Cyclodextrin/dextran based hydrogels prepared by cross-linking with sodium trimetaphosphate.

    Science.gov (United States)

    Wintgens, Véronique; Lorthioir, Cédric; Dubot, Pierre; Sébille, Bernard; Amiel, Catherine

    2015-11-01

    Novel βCD-based hydrogels have been synthesized using sodium trimetaphosphate (STMP) as non-toxic reagent. Straightforward mixing of βCD with dextran and STMP in basic aqueous media led to hydrogels incorporating dextran chains, phosphate groups and βCD units. The hydrogels have been characterized by swelling measurements, XPS and (31)P NMR. The swelling ratio was correlated to the content in phosphated groups, which give a polyelectrolyte character to these hydrogels. The significant rise of the swelling ratio with the βCD content increase has been attributed to a decrease of the number of phosphate-based crosslinks, the βCD units playing the role of dangling ends in the tridimensional network. Their loading capacity and their release properties have been investigated for methylene blue and benzophenone in order to demonstrate their potentiality for drug delivery. Through different interaction mechanisms, electrostatic and inclusion complex interactions, these compounds are loaded with different efficiencies. The release involves deswelling, diffusion mechanisms and partition equilibrium.

  12. Rapid microwave-assisted synthesis of dextran-coated iron oxide nanoparticles for magnetic resonance imaging

    Science.gov (United States)

    Osborne, Elizabeth A.; Atkins, Tonya M.; Gilbert, Dustin A.; Kauzlarich, Susan M.; Liu, Kai; Louie, Angelique Y.

    2012-06-01

    Currently, magnetic iron oxide nanoparticles are the only nanosized magnetic resonance imaging (MRI) contrast agents approved for clinical use, yet commercial manufacturing of these agents has been limited or discontinued. Though there is still widespread demand for these particles both for clinical use and research, they are difficult to obtain commercially, and complicated syntheses make in-house preparation unfeasible for most biological research labs or clinics. To make commercial production viable and increase accessibility of these products, it is crucial to develop simple, rapid and reproducible preparations of biocompatible iron oxide nanoparticles. Here, we report a rapid, straightforward microwave-assisted synthesis of superparamagnetic dextran-coated iron oxide nanoparticles. The nanoparticles were produced in two hydrodynamic sizes with differing core morphologies by varying the synthetic method as either a two-step or single-step process. A striking benefit of these methods is the ability to obtain swift and consistent results without the necessity for air-, pH- or temperature-sensitive techniques; therefore, reaction times and complex manufacturing processes are greatly reduced as compared to conventional synthetic methods. This is a great benefit for cost-effective translation to commercial production. The nanoparticles are found to be superparamagnetic and exhibit properties consistent for use in MRI. In addition, the dextran coating imparts the water solubility and biocompatibility necessary for in vivo utilization.

  13. Aponecrotic, antiangiogenic and antiproliferative effects of a novel dextran derivative on breast cancer growth in vitro and in vivo

    OpenAIRE

    Benedetto, Mélanie Di; Starzec, Anna; Colombo, Bruno M; Briane, Dominique; Perret, Gérard Y; Kraemer, Michel; Crépin, Michel

    2002-01-01

    1 Since the sodium phenylacetate (NaPa) was reported to enhance the inhibitory effect of carboxymethyl benzylamide dextran (CMDB) on the breast cancer growth, we performed the esterification of CMDB with NaPa to obtain a new drug carrying the characteristics of these two components. A new molecule, phenylacetate carboxymethyl benzylamide dextran, was named NaPaC.We investigated in vitro and in vivo the effects of NaPaC on MCF-7ras cell growth as well as its apoptotic and antiangiogenic effect...

  14. A comparative biocompatibility study of micropheres based on crosslinked dextran or poly(lactic-co-glycolic)acid after subcutaneous injection in rats

    NARCIS (Netherlands)

    Cadee, JA; Brouwer, LA; den Otter, W; Hennink, WE; van Luyn, MJA

    2001-01-01

    Microspheres based on methacrylated dextran (dex-MA), dextran derivatized with lactate-hydroxyethyl methacrylate (dex-lactate-HEMA) or derivatized with HEMA (dex-HEMA) were prepared. The microspheres were injected subcutaneously in rats and the effect of the particle size and network characteristics

  15. Protein-polysaccharide interactions: The determination of the osmotic second virial coefficients in aqueous solutions of ß-lactoglobulin and dextran

    NARCIS (Netherlands)

    Schaink, H.M.; Smit, J.A.M.

    2007-01-01

    Solutions containing dextran and solutions containing mixtures of dextran +ß-lactoglobulin are studied by membrane osmometry. The low concentration range of these solutions is considered. From the measured osmotic pressures the virial coefficients are obtained. These are analyzed using the osmotic

  16. Evaluation of changes in serum chemistry in association with feed withdrawal or high dose oral gavage with Dextran Sodium Sulfate (DSS) induced gut leakage in broiler chickens

    Science.gov (United States)

    Dextran sodium sulfate (DSS) has been shown to be effective at inducing enteric inflammation in broiler chickens, resulting in increased leakage of orally administered fluorescein isothiocyanate dextran to circulation. In a previous study, two doses of DSS (0.45g/dose) administered as oral gavage re...

  17. A comparative biocompatibility study of micropheres based on crosslinked dextran or poly(lactic-co-glycolic)acid after subcutaneous injection in rats

    NARCIS (Netherlands)

    Cadee, JA; Brouwer, LA; den Otter, W; Hennink, WE; van Luyn, MJA

    2001-01-01

    Microspheres based on methacrylated dextran (dex-MA), dextran derivatized with lactate-hydroxyethyl methacrylate (dex-lactate-HEMA) or derivatized with HEMA (dex-HEMA) were prepared. The microspheres were injected subcutaneously in rats and the effect of the particle size and network characteristics

  18. Protein-polysaccharide interactions: The determination of the osmotic second virial coefficients in aqueous solutions of ß-lactoglobulin and dextran

    NARCIS (Netherlands)

    Schaink, H.M.; Smit, J.A.M.

    2007-01-01

    Solutions containing dextran and solutions containing mixtures of dextran +ß-lactoglobulin are studied by membrane osmometry. The low concentration range of these solutions is considered. From the measured osmotic pressures the virial coefficients are obtained. These are analyzed using the osmotic v

  19. Nitrite consumption and associated isotope changes during a river flood event

    Science.gov (United States)

    Jacob, Juliane; Sanders, Tina; Dähnke, Kirstin

    2016-10-01

    In oceans, estuaries, and rivers, nitrification is an important nitrate source, and stable isotopes of nitrate are often used to investigate recycling processes (e.g. remineralisation, nitrification) in the water column. Nitrification is a two-step process, where ammonia is oxidised via nitrite to nitrate. Nitrite usually does not accumulate in natural environments, which makes it difficult to study the single isotope effect of ammonia oxidation or nitrite oxidation in natural systems. However, during an exceptional flood in the Elbe River in June 2013, we found a unique co-occurrence of ammonium, nitrite, and nitrate in the water column, returning towards normal summer conditions within 1 week. Over the course of the flood, we analysed the evolution of δ15N-NH4+ and δ15N-NO2- in the Elbe River. In concert with changes in suspended particulate matter (SPM) and δ15N SPM, as well as nitrate concentration, δ15N-NO3- and δ18O-NO3-, we calculated apparent isotope effects during net nitrite and nitrate consumption. During the flood event, > 97 % of total reactive nitrogen was nitrate, which was leached from the catchment area and appeared to be subject to assimilation. Ammonium and nitrite concentrations increased to 3.4 and 4.4 µmol L-1, respectively, likely due to remineralisation, nitrification, and denitrification in the water column. δ15N-NH4+ values increased up to 12 ‰, and δ15N-NO2- ranged from -8.0 to -14.2 ‰. Based on this, we calculated an apparent isotope effect 15ɛ of -10.0 ± 0.1 ‰ during net nitrite consumption, as well as an isotope effect 15ɛ of -4.0 ± 0.1 ‰ and 18ɛ of -5.3 ± 0.1 ‰ during net nitrate consumption. On the basis of the observed nitrite isotope changes, we evaluated different nitrite uptake processes in a simple box model. We found that a regime of combined riparian denitrification and 22 to 36 % nitrification fits best with measured data for the nitrite concentration decrease and isotope increase.

  20. Action of arginine for protection of ulcerative colitis by dextran sodium sulphate (DSS); Acao da arginina na protecao da colite ulcerativa induzida por sulfato de sodio dextrano

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Maria Emilia Rabelo

    2016-10-01

    Recent studies have demonstrated the benefits of immunomodulators, such as arginine, in the regulation of inflammatory responses and trophism of the intestinal mucosa. The aim of this study was to evaluate the possible mechanisms action of arginine (pretreatment or treatment) in experimental model of ulcerative colitis induced by dextran sodium sulfate (DSS). C57BL/6 mice were randomized into 5 groups: Control group (C): standard diet and water; Arginine group (ARG): diet supplementation with arginine and water; Colitis group (COL): standard diet and DSS solution; Pretreated group (PT): diet supplementation with arginine before and during colitis induction; Treated group (T): diet supplementation with arginine during colitis induction. Colitis was induced by administration of 1.5% DSS for 5 days. After this, all the mice were euthanized and blood, organs and intestinal fluid were collected for carrying out analyzes. Parameters such as intestinal permeability (IP), bacterial translocation (BT), histological analysis (histological score, morphometric analysis, collagen and mucins stain), nitrate and nitrite, cytokines and chemokines, secretory immunoglobulin A (sIgA), inflammatory infiltrate and oxidative stress were performed. The ARG group did not show difference compared to group C in the investigated parameters (C vs ARG: p> 0.05). The COL group showed increased IP (C vs COL: p < 0.05) and BT (C vs COL: p <0.05). In the histological analysis, the COL group showed severe inflammation and reduction the crypts length. In addition, in the group COL observed increase infiltration of eosinophils, neutrophils and macrophages in the colon, increase cytokine IL-17 and chemokine KC in serum and oxidative stress in the colon (COL vs C: p <0.05). In the arginine-supplemented groups (PT and T) was observed decrease IP and BT to blood, liver and lung (PT and T vs Col: p <0.05). Histological analysis showed that the arginine (PT and T) preserved the intestinal mucosa and crypts

  1. Cacao polyphenols ameliorate autoimmune myocarditis in mice.

    Science.gov (United States)

    Zempo, Hirofumi; Suzuki, Jun-ichi; Watanabe, Ryo; Wakayama, Kouji; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Komuro, Issei; Isobe, Mitsuaki

    2016-04-01

    Myocarditis is a clinically severe disease; however, no effective treatment has been established. The aim of this study was to determine whether cacao bean (Theobroma cacao) polyphenols ameliorate autoimmune myocarditis. We used an experimental autoimmune myocarditis (EAM) model in Balb/c mice. Mice with induced EAM were treated with a cacao polyphenol extract (CPE, n=12) or vehicle (n=12). On day 21, hearts were harvested and analyzed. Elevated heart weight to body weight and fibrotic area ratios as well as high cardiac cell infiltration were observed in the vehicle-treated EAM mice. However, these increases were significantly suppressed in the CPE-treated mice. Reverse transcriptase-PCR revealed that mRNA expressions of interleukin (Il)-1β, Il-6, E-selectin, vascular cell adhesion molecule-1 and collagen type 1 were lower in the CPE group compared with the vehicle group. The mRNA expressions of nicotinamide adenine dinucleotide phosphate-oxidase (Nox)2 and Nox4 were increased in the vehicle-treated EAM hearts, although CPE treatment did not significantly suppress the transcription levels. However, compared with vehicle treatment of EAM hearts, CPE treatment significantly suppressed hydrogen peroxide concentrations. Cardiac myeloperoxidase activity, the intensity of dihydroethidium staining and the phosphorylation of nuclear factor-κB p65 were also lower in the CPE group compared with the vehicle group. Our data suggest that CPE ameliorates EAM in mice. CPE is a promising dietary supplement to suppress cardiovascular inflammation and oxidative stress.

  2. Acetylcholinesterase inhibition ameliorates deficits in motivational drive

    Directory of Open Access Journals (Sweden)

    Martinowich Keri

    2012-03-01

    Full Text Available Abstract Background Apathy is frequently observed in numerous neurological disorders, including Alzheimer's and Parkinson's, as well as neuropsychiatric disorders including schizophrenia. Apathy is defined as a lack of motivation characterized by diminished goal-oriented behavior and self-initiated activity. This study evaluated a chronic restraint stress (CRS protocol in modeling apathetic behavior, and determined whether administration of an anticholinesterase had utility in attenuating CRS-induced phenotypes. Methods We assessed behavior as well as regional neuronal activity patterns using FosB immunohistochemistry after exposure to CRS for 6 h/d for a minimum of 21 d. Based on our FosB findings and recent clinical trials, we administered an anticholinesterase to evaluate attenuation of CRS-induced phenotypes. Results CRS resulted in behaviors that reflect motivational loss and diminished emotional responsiveness. CRS-exposed mice showed differences in FosB accumulation, including changes in the cholinergic basal forebrain system. Facilitating cholinergic signaling ameliorated CRS-induced deficits in initiation and motivational drive and rescued immediate early gene activation in the medial septum and nucleus accumbens. Conclusions Some CRS protocols may be useful for studying deficits in motivation and apathetic behavior. Amelioration of CRS-induced behaviors with an anticholinesterase supports a role for the cholinergic system in remediation of deficits in motivational drive.

  3. Safety and feasibility of long-term intravenous sodium nitrite infusion in healthy volunteers.

    Directory of Open Access Journals (Sweden)

    Ryszard M Pluta

    Full Text Available BACKGROUND: Infusion of sodium nitrite could provide sustained therapeutic concentrations of nitric oxide (NO for the treatment of a variety of vascular disorders. The study was developed to determine the safety and feasibility of prolonged sodium nitrite infusion. METHODOLOGY: Healthy volunteers, aged 21 to 60 years old, were candidates for the study performed at the National Institutes of Health (NIH; protocol 05-N-0075 between July 2007 and August 2008. All subjects provided written consent to participate. Twelve subjects (5 males, 7 females; mean age, 38.8±9.2 years (range, 21-56 years were intravenously infused with increasing doses of sodium nitrite for 48 hours (starting dose at 4.2 µg/kg/hr; maximal dose of 533.8 µg/kg/hr. Clinical, physiologic and laboratory data before, during and after infusion were analyzed. FINDINGS: The maximal tolerated dose for intravenous infusion of sodium nitrite was 267 µg/kg/hr. Dose limiting toxicity occurred at 446 µg/kg/hr. Toxicity included a transient asymptomatic decrease of mean arterial blood pressure (more than 15 mmHg and/or an asymptomatic increase of methemoglobin level above 5%. Nitrite, nitrate, S-nitrosothiols concentrations in plasma and whole blood increased in all subjects and returned to preinfusion baseline values within 12 hours after cessation of the infusion. The mean half-life of nitrite estimated at maximal tolerated dose was 45.3 minutes for plasma and 51.4 minutes for whole blood. CONCLUSION: Sodium nitrite can be safely infused intravenously at defined concentrations for prolonged intervals. These results should be valuable for developing studies to investigate new NO treatment paradigms for a variety of clinical disorders, including cerebral vasospasm after subarachnoid hemorrhage, and ischemia of the heart, liver, kidney and brain, as well as organ transplants, blood-brain barrier modulation and pulmonary hypertension. CLINICAL TRIAL REGISTRATION INFORMATION: http

  4. Crystal Structures of the Nitrite and Nitric Oxide Complexes of Horse Heart Myoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Copeland,D.; Soares, A.; West, A.; Richter-Addo, G.

    2006-01-01

    Nitrite is an important species in the global nitrogen cycle, and the nitrite reductase enzymes convert nitrite to nitric oxide (NO). Recently, it has been shown that hemoglobin and myoglobin catalyze the reduction of nitrite to NO under hypoxic conditions. We have determined the 1.20 Angstroms resolution crystal structure of the nitrite adduct of ferric horse heart myoglobin (hh Mb). The ligand is bound to iron in the nitrito form, and the complex is formulated as Mb{sup III}(ONO{sup -}). The Fe-ONO bond length is 1.94 Angstroms, and the O-N-O angle is 113 degrees. In addition, the nitrite ligand is stabilized by hydrogen bonding with the distal His64 residue. We have also determined the 1.30 Angstroms resolution crystal structures of hh Mb{sup II}NO. When hh Mb{sup II}NO is prepared from the reaction of metMb{sup III} with nitrite/dithionite, the FeNO angle is 144 degrees with a Fe-NO bond length of 1.87 Angstroms. However, when prepared from the reaction of NO with reduced Mb{sup II}, the FeNO angle is 120 degrees with a Fe-NO bond length of 2.13 Angstroms. This difference in FeNO conformations as a function of preparative method is reproducible, and suggests a role of the distal pocket in hh Mb{sup II}NO in stabilizing local FeNO conformational minima.

  5. The capacity of red blood cells to reduce nitrite determines nitric oxide generation under hypoxic conditions.

    Directory of Open Access Journals (Sweden)

    Marcel H Fens

    Full Text Available Nitric oxide (NO is a key regulator of vascular tone. Endothelial nitric oxide synthase (eNOS is responsible for NO generation under normoxic conditions. Under hypoxia however, eNOS is inactive and red blood cells (RBC provide an alternative NO generation pathway from nitrite to regulate hypoxic vasodilation. While nitrite reductase activity of hemoglobin is well acknowledged, little is known about generation of NO by intact RBC with physiological hemoglobin concentrations. We aimed to develop and apply a new approach to provide insights in the ability of RBC to convert nitrite into NO under hypoxic conditions. We established a novel experimental setup to evaluate nitrite uptake and the release of NO from RBC into the gas-phase under different conditions. NO measurements were similar to well-established clinical measurements of exhaled NO. Nitrite uptake was rapid, and after an initial lag phase NO release from RBC was constant in time under hypoxic conditions. The presence of oxygen greatly reduced NO release, whereas inhibition of eNOS and xanthine oxidoreductase (XOR did not affect NO release. A decreased pH increased NO release under hypoxic conditions. Hypothermia lowered NO release, while hyperthermia increased NO release. Whereas fetal hemoglobin did not alter NO release compared to adult hemoglobin, sickle RBC showed an increased ability to release NO. Under all conditions nitrite uptake by RBC was similar. This study shows that nitrite uptake into RBC is rapid and release of NO into the gas-phase continues for prolonged periods of time under hypoxic conditions. Changes in the RBC environment such as pH, temperature or hemoglobin type, affect NO release.

  6. The capacity of red blood cells to reduce nitrite determines nitric oxide generation under hypoxic conditions.

    Science.gov (United States)

    Fens, Marcel H; Larkin, Sandra K; Oronsky, Bryan; Scicinski, Jan; Morris, Claudia R; Kuypers, Frans A

    2014-01-01

    Nitric oxide (NO) is a key regulator of vascular tone. Endothelial nitric oxide synthase (eNOS) is responsible for NO generation under normoxic conditions. Under hypoxia however, eNOS is inactive and red blood cells (RBC) provide an alternative NO generation pathway from nitrite to regulate hypoxic vasodilation. While nitrite reductase activity of hemoglobin is well acknowledged, little is known about generation of NO by intact RBC with physiological hemoglobin concentrations. We aimed to develop and apply a new approach to provide insights in the ability of RBC to convert nitrite into NO under hypoxic conditions. We established a novel experimental setup to evaluate nitrite uptake and the release of NO from RBC into the gas-phase under different conditions. NO measurements were similar to well-established clinical measurements of exhaled NO. Nitrite uptake was rapid, and after an initial lag phase NO release from RBC was constant in time under hypoxic conditions. The presence of oxygen greatly reduced NO release, whereas inhibition of eNOS and xanthine oxidoreductase (XOR) did not affect NO release. A decreased pH increased NO release under hypoxic conditions. Hypothermia lowered NO release, while hyperthermia increased NO release. Whereas fetal hemoglobin did not alter NO release compared to adult hemoglobin, sickle RBC showed an increased ability to release NO. Under all conditions nitrite uptake by RBC was similar. This study shows that nitrite uptake into RBC is rapid and release of NO into the gas-phase continues for prolonged periods of time under hypoxic conditions. Changes in the RBC environment such as pH, temperature or hemoglobin type, affect NO release.

  7. TERRA E SUA ASSOCIAÇÃO COM FERRO DEXTRAN NO DESEMPENHO DE LEITÕES EM ALEITAMENTO LAND AND ITS ASSOCIATION WITH IRON DEXTRAN IN THE PERFORMANCE OF PIGLETS

    Directory of Open Access Journals (Sweden)

    Sergito de Souza Cavalcanti

    2007-09-01

    Full Text Available

    Na central de Suínos de Goiás, no município de Senador Canedo, foi realizada esta pesquisa, onde se utilizou leitegada de quinze porcas Large White com a finalidade de se verificar o efeito da terra e de sua associação com ferro dextran no desempenho de leitões, aos 21 e 36 dias da idade. Os tratamentos utilizados foram os seguintes: T1 - 100 mg do ferro dextran via intramuscular no terceiro dia de vida dos leitões; T2 -50 mg de ferro dextran via intramuscular no terceiro dia de vida dos leitões mais 1,0 Kg de terra/dia do terceiro ao trigésimo quinto dia; T3 - 2,0 kg de terra/dia do terceiro ao trigésimo quinto dia de vida dos leitões. Observadas as condições em que foi realizado o experimento, conclui-se que: 1 a substituição de 50 mg de ferro dextran por 1,0 kg de terra/dia, do terceiro ao trigésimo quinto dia de vida dos leitões é tão eficiente quanto 100 mg de ferro dextran injetável intramuscularmente ao terceiro dia de vida; 2 o uso de 2,0 kg de terra diariamente do terceiro ao trigésimo quinto dia de vida dos leitões teve um desempenho inferior aos demais tratamentos.

    This research was developed in the Central Pig Farm in the county of Senador Canedo in Goiás State. Litters from 15 Large White sows were used to investigate the effect of feeding ground and its association with iron dextran to piglets from the third day of age. The evaluation of the effects of the treatments in the development of the piglets was done at 21 and 35 days of age. The treatments were as follow: T1 - 100 mg of iron dextran, via intramuscular, at the third day of age; T2 - 50 mg of iron dextran, via intramuscular, at the third day of age in association with 1.0 kg of ground, fed daily from the third to the 35th day of age; T3 - 2.0 kg of ground, daily, from the third to the 35th day of age. After observing

  8. Normoxic cyclic GMP-independent oxidative signaling by nitrite enhances airway epithelial cell proliferation and wound healing.

    Science.gov (United States)

    Wang, Ling; Frizzell, Sheila A; Zhao, Xuejun; Gladwin, Mark T

    2012-05-15

    The airway epithelium provides important barrier and host defense functions. Recent studies reveal that nitrite is an endocrine reservoir of nitric oxide (NO) bioactivity that is converted to NO by enzymatic reductases along the physiological oxygen gradient. Nitrite signaling has been described as NO dependent activation mediated by reactions with deoxygenated redox active hemoproteins, such as hemoglobin, myoglobin, neuroglobin, xanthine oxidoreductase (XO) and NO synthase at low pH and oxygen tension. However, nitrite can also be readily oxidized to nitrogen dioxide (NO(2)·) via heme peroxidase reactions, suggesting the existence of alternative oxidative signaling pathways for nitrite under normoxic conditions. In the present study, we examined normoxic signaling effects of sodium nitrite on airway epithelial cell wound healing. In an in vitro scratch injury model under normoxia, we exposed cultured monolayers of human airway epithelial cells to various concentrations of sodium nitrite and compared responses to NO donor. We found sodium nitrite potently enhanced airway epithelium wound healing at physiological concentrations (from 1 μM). The effect of nitrite was blocked by the NO and NO(2)· scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO). Interestingly, nitrite treatment did not increase cyclic guanosine monophosphate (cGMP) levels under these normoxic conditions, even in the presence of a phosphodiesterase 5 inhibitor, suggesting cGMP independent signaling. Consistent with an oxidative signaling pathway requiring hydrogen peroxide (H(2)O(2))/heme-peroxidase/NO(2)· signaling, the effects of nitrite were potentiated by superoxide dismutase (SOD) and low concentration H(2)O(2), whereas inhibited completely by catalase, followed by downstream extracellular-signal-regulated kinase (ERK) 1/2 activation. Our data represent the first description of normoxic nitrite signaling on lung epithelial cell proliferation and wound

  9. Use of lysozyme from chicken egg white as a nitrite replacer in an Italian-type chicken sausage

    OpenAIRE

    Nalaka Sandun Abeyrathne; Ishani A.H.M.E.Herath; Jayasinghe J. M. Priyanath; Ahn, Dong U.

    2015-01-01

    Background: Sodium or potassium nitrite is widely used as a curing agent in sausages and other cured meat products. Nitrite has strong antimicrobial and antioxidant effects and generates cured meat color. Nitrite, however, can react with secondary or tertiary amines in meat to form carcinogenic, teratogenic and mutagenic N-nitroso compounds. Several findings have been suggested that high consumption of processed meat may increase the risk of cancer, and emphasized that dietary nitrosamines ar...

  10. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334 ameliorates murine colitis

    Directory of Open Access Journals (Sweden)

    Gupta R

    2014-01-01

    Full Text Available Ram Gupta,1 Anita R Chaudhary,2 Binita N Shah,1 Avinash V Jadhav,3 Shitalkumar P Zambad,1 Ramesh Chandra Gupta,4 Shailesh Deshpande,4 Vijay Chauthaiwale,4 Chaitanya Dutt4 1Department of Pharmacology, 2Cellular and Molecular Biology, 3Preclinical Safety Evaluation, 4Discovery, Torrent Research Centre, Torrent Pharmaceuticals Ltd, Gandhinagar, Gujarat, India Background and aim: Mucosal healing in inflammatory bowel disease (IBD can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods: The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn's disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results: TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion: Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor

  11. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334) ameliorates murine colitis

    Science.gov (United States)

    Gupta, Ram; Chaudhary, Anita R; Shah, Binita N; Jadhav, Avinash V; Zambad, Shitalkumar P; Gupta, Ramesh Chandra; Deshpande, Shailesh; Chauthaiwale, Vijay; Dutt, Chaitanya

    2014-01-01

    Background and aim Mucosal healing in inflammatory bowel disease (IBD) can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF) has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn’s disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor ameliorates IBD in disease models. These findings highlight the potential of TRC160334 for its clinical application in the treatment of IBD. PMID:24493931

  12. Orally Administered Enoxaparin Ameliorates Acute Colitis by Reducing Macrophage-Associated Inflammatory Responses

    Science.gov (United States)

    Lean, Qi Ying; Eri, Rajaraman D.; Randall-Demllo, Sarron; Sohal, Sukhwinder Singh; Stewart, Niall; Peterson, Gregory M.; Gueven, Nuri; Patel, Rahul P.

    2015-01-01

    Inflammatory bowel diseases, such as ulcerative colitis, cause significant morbidity and decreased quality of life. The currently available treatments are not effective in all patients, can be expensive and have potential to cause severe side effects. This prompts the need for new treatment modalities. Enoxaparin, a widely used antithrombotic agent, is reported to possess anti-inflammatory properties and therefore we evaluated its therapeutic potential in a mouse model of colitis. Acute colitis was induced in male C57BL/6 mice by administration of dextran sulfate sodium (DSS). Mice were treated once daily with enoxaparin via oral or intraperitoneal administration and monitored for colitis activities. On termination (day 8), colons were collected for macroscopic evaluation and cytokine measurement, and processed for histology and immunohistochemistry. Oral but not intraperitoneal administration of enoxaparin significantly ameliorated DSS-induced colitis. Oral enoxaparin-treated mice retained their body weight and displayed less diarrhea and fecal blood loss compared to the untreated colitis group. Colon weight in enoxaparin-treated mice was significantly lower, indicating reduced inflammation and edema. Histological examination of untreated colitis mice showed a massive loss of crypt architecture and goblet cells, infiltration of immune cells and the presence of edema, while all aspects of this pathology were alleviated by oral enoxaparin. Reduced number of macrophages in the colon of oral enoxaparin-treated mice was accompanied by decreased levels of pro-inflammatory cytokines. Oral enoxaparin significantly reduces the inflammatory pathology associated with DSS-induced colitis in mice and could therefore represent a novel therapeutic option for the management of ulcerative colitis. PMID:26218284

  13. The antiprotozoal drug pentamidine ameliorates experimentally induced acute colitis in mice

    Directory of Open Access Journals (Sweden)

    Esposito Giuseppe

    2012-12-01

    Full Text Available Abstract Background Intestinal inflammation is partly driven by enteroglial-derived S100B protein. The antiprotozoal drug pentamidine directly blocks S100B activity. We aimed to investigate the effect of pentamidine on intestinal inflammation using an animal model of dextran sodium sulphate (DSS-induced acute colitis. Methods Mice were divided into: control group, colitis group (4% DSS for four days and two pentamidine-treated colitis groups (0.8 mg/kg and 4 mg/kg. Anti-inflammatory effect of pentamidine was assessed in colonic tissue by evaluating the disease activity index and the severity of histological changes. Colonic tissue were also used to evaluate cyclooxigenase-2, inducible nitric oxide synthase, S100B, glial fibrillary acidic protein, phosphorylated-p38 MAPkinase, p50, p65 protein expression, malondyaldheyde production, mieloperoxidase activity, and macrophage infiltration. Nitric oxide, prostaglandin E2, interleukin-1 beta, tumor necrosis factor alpha, and S100B levels were detected in plasma samples. Parallel measurements were performed in vitro on dissected mucosa and longitudinal muscle myenteric plexus (LMMP preparations after challenge with LPS + DSS or exogenous S100B protein in the presence or absence of pentamidine. Results Pentamidine treatment significantly ameliorated the severity of acute colitis in mice, as showed by macroscopic evaluation and histological/biochemical assays in colonic tissues and in plasma. Pentamidine effect on inflammatory mediators was almost completely abrogated in dissected mucosa but not in LMMP. Conclusions Pentamidine exerts a marked anti-inflammatory effect in a mice model of acute colitis, likely targeting S100B activity. Pentamidine might be an innovative molecule to broaden pharmacological tools against colitis.

  14. The formation of magnetic carboxymethyl-dextrane-coated iron-oxide nanoparticles using precipitation from an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Gyergyek, Sašo, E-mail: saso.gyergyek@ijs.si [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Primc, Darinka [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Plantan, Ivan [Lek Pharmaceuticals d.d., Mengeš (Slovenia)

    2015-03-01

    The formation of spinel iron-oxide nanoparticles during the co-precipitation of Fe{sup 3+}/Fe{sup 2+} ions from an aqueous solution in the presence of carboxymethyldextrane (CMD) was studied. To follow the formation of the nanoparticles, a mixture of the Fe ions, CMD and ammonia was heated to different temperatures, while the samples were taken, quenched in liquid nitrogen, freeze-dried and characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD) and magnetometry. The CMD plays a role in the reactions of the Fe ions' precipitation by partially immobilizing the Fe{sup 3+} ions into a complex. At room temperature, the amorphous material is precipitated. Then, above approximately 30 °C, the spinel nanoparticles form inside the amorphous matrix, and at approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles. The CMD bonded to the nanoparticles' surfaces hinders the mass transport and thus prevents their growth. - Highlights: • The carboxymethyl-dextrane coated iron-oxide nanoparticles were synthesized. • The carboxymethyl-dextrane significantly modifies formation of the spinel nanoparticles. • The spinel nanoparticles are formed inside the amorphous matrix. • At approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles.

  15. Synthesis of silver nanoparticles in the presence of diethylaminoethyl-dextran hydrochloride polymer and their SERS activity

    Science.gov (United States)

    Mikac, L.; Jurkin, T.; Štefanić, G.; Ivanda, Mile; Gotić, Marijan

    2017-09-01

    The silver nanoparticles (AgNPs) were synthesized upon γ-irradiation of AgNO3 precursor suspensions in the presence of diethylaminoethyl-dextran hydrochloride (DEAE-dextran) cationic polymer as a stabilizer. The dose rate of γ-irradiation was 32 kGy h-1, and absorbed doses were 30 and 60 kGy. The γ-irradiation of the precursor suspension at acidic or neutral pH conditions produced predominantly the silver(I) chloride (AgCl) particles, because of the poor solubility of AgCl already present in the precursor suspension. The origin of AgCl in the precursor suspension was due to the presence of chloride ions in DEAE-dextran hydrochloride polymer. The addition of ammonia to the precursor suspension dissolved the AgCl precipitate, and the γ-irradiation of such colourless suspension at alkali pH produced a stable aqueous suspension with rather uniform spherical AgNPs of approximately 30 nm in size. The size of AgNPs was controlled by varying the AgNO3/DEAE-dextran concentration in the suspensions. The surface-enhanced Raman scattering (SERS) activities of synthesized AgNPs were examined using organic molecules rhodamine 6G, pyridine and 4-mercaptobenzoic acid (4-MBA). The NaBH4 was used as SERS aggregation agent. The SERS results have shown that in the presence of synthesized AgNPs, it was possible to detect low concentration of tested compounds.

  16. Histology of a novel injectable filler (polymethylmethacrylate and cross-linked dextran in hydroxypropyl methylcellulose) in a rat model.

    Science.gov (United States)

    Lee, Young Bok; Park, Sae Mi; Song, Eun Jong; Park, Jun-Gyu; Cho, Kyoung-Oh; Kim, Jin Wou; Yu, Dong Soo

    2014-08-01

    A novel injectable filler of polymethylmethacrylate (PMMA) and cross-linked dextran in hydroxypropyl methylcellulose was introduced in the commercial filler market. For soft tissue augmentation, safety and biocompatibility should be evaluated and the stability at the implantation site should be assessed using histologic evaluation. In order to evaluate the biocompatibility of the novel soft tissue filler, PMMA and cross-linked dextran in hydroxypropyl methylcellulose was subdermally injected into the skin of Sprague-Dawley Rats. Histologic evaluation was performed at 13 weeks and 12 months after the injection. Inflammatory cell infiltration, neovascularization, and fibrosis were scored according to defined grading systems. The mean score of the histologic evaluation was 5.7 and 3.9 at 13 weeks and 12 months, respectively. At 12 months after injection, the PMMA and cross-linked dextran in hydroxypropyl methylcellulose appeared to be kept in place through fine fibrous capsules. The mixture of PMMA and cross-linked dextran in hydroxypropyl methylcellulose can be safely applied for soft tissue augmentation with longevity of greater than 12 months.

  17. Physicochemical stability and in vitro bioaccessibility of ß-carotene nanoemulsions stabilized with whey protein-dextran conjugates

    Science.gov (United States)

    In this study, ß-carotene (BC)-loaded nanoemulsions encapsulated with native whey protein isolate (WPI) and WPI-dextran (DT, 5 kDa, 20 kDa, and 70 kDa) conjugates were prepared and the effects of glycosylation with various molecular weight DTs on the physicochemical property, lipolysis, and BC bioac...

  18. Dextran-graft-linear poly(ethylene imine)s for gene delivery: importance of the linking strategy.

    Science.gov (United States)

    Ochrimenko, Sofia; Vollrath, Antje; Tauhardt, Lutz; Kempe, Kristian; Schubert, Stephanie; Schubert, Ulrich S; Fischer, Dagmar

    2014-11-26

    Low molar mass linear poly(ethylene imine)s (lPEI) were grafted onto dextran via different synthesis routes aiming at the elucidation of structure-property relationships of dextran-graft-linear poly(ethylene imine) (dex-g-lPEI) conjugates for gene delivery applications. Beside the molar mass of well-defined lPEIs and the linker unit, also the amount of lPEI in the polymeric vectors was varied. The synthesized dextran modifications were characterized regarding their chemical structure and showed enhanced complexation and stabilization of DNA against enzymatic degradation. The transfection efficiency of dex-g-lPEIs was increased compared to unmodified lPEI and revealed a dependency of the used linking strategy. All complexes of DNA and dex-g-lPEIs were found to be nontoxic, but the synthesis route showed a strong influence on the aggregation of red blood cells. In conclusion, the linking strategy of lPEI to dextran has a significant impact on the physicochemical characteristics of DNA/polymer complexes, the biocompatibility as well as the transfection efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Diffusion of dextran probes in a self-assembled fibrous gel composed of two-dimensional arborols.

    Science.gov (United States)

    Sun, Jirun; Lyles, Bethany F; Yu, Keunok Han; Weddell, Jaime; Pople, John; Hetzer, Max; De Kee, Daniel; Russo, Paul S

    2008-01-10

    Two-dimensional arborols are bolaform amphiphiles in which a central, hydrophobic spacer separates twin hydrophilic ends. Under appropriate conditions, these relatively small molecules assemble into very long fibers; subsequently, the system gels if the arborol concentration is sufficiently high. The diffusion of linear or slightly branched dextran probes in 3 and 6% arborol gels, as determined by fluorescence photobleaching recovery, resembles that of dextrans in water, suggesting a highly open network structure. Melting the gels produces almost no change in diffusion of the dextran probes. Small-angle X-ray scattering (SAXS) of wet arborol gels at different concentrations and temperatures reveals the diameter of the repeating unit of the fibers to be 8.26+/-0.68 nm. This dimension, which is independent of concentration and temperature, exceeds the length of a single arborol molecule by about a factor of 3. Rheological investigation identifies the linear response regime of the gels and permits an examination of the weak correlation between dextran probe diffusion and gel viscoelasticity.

  20. Treatment outcome of additional dextran to corticosteroid therapy on sudden deafness: propensity score-matched cohort analysis.

    Science.gov (United States)

    Wang, Chi-Te; Chou, Hsu-Wen; Fang, Kai-Min; Lai, Mei-Shu; Cheng, Po-Wen

    2012-12-01

    This study aimed to investigate whether adding low-molecular-weight dextran to oral steroids in patients with idiopathic sudden sensorineural hearing loss resulted in better hearing outcomes than those in patients receiving oral corticosteroids alone. Historical cohort study. Tertiary teaching hospital. The authors reviewed the clinical records of 166 patients with idiopathic sudden sensorineural hearing loss. Therapeutic effectiveness was measured by the gain of pure-tone averages and 4 categories of hearing outcome (complete recovery, marked recovery, mild improvement, or no improvement). To manage potential confounding factors associated with treatment allocation, the authors matched the subjects from each group according to the propensity score (ie, the predicted probability that they would receive a specific treatment). The authors identified 50 pairs of propensity score-matched subjects (n = 100) without significant difference of all clinical factors (P > .05). Subsequent analyses demonstrated that the average hearing gain in subjects receiving additional dextran to oral steroid was 31.7 ± 21.5 dB, which did not differ from 33.0 ± 21.8 dB in subjects receiving steroids alone (P = .76). Difference of hearing outcomes between the 2 groups was also nonsignificant (P = .92). Matching propensity scores successfully balanced the heterogeneity between the dextran and steroid groups. Analytical results demonstrated that adding low-molecular-weight dextran to oral corticosteroids was not associated with greater hearing gain or better hearing outcome in idiopathic sudden sensorineural hearing loss.

  1. Structure and Antioxidant Activity of Soy Protein Isolate-Dextran Conjugates Obtained by TiO2 Photocatalysis

    Directory of Open Access Journals (Sweden)

    Bei Jin

    2015-01-01

    Full Text Available The aim of this study was to investigate the structural characteristics and antioxidant activities of soy protein isolate- (SPI- dextran conjugates obtained by TiO2 photocatalysis treatment. Results revealed that the UV-vis absorption and the fluorescence intensity increased as the photocatalytic power increased (P<0.05. Higher photocatalytic power could promote the extent of glycation and the formation of high molecular weight SPI-dextran conjugates, which were evidenced by free amino group content and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE analysis. The Fourier transform infrared (FT-IR spectra suggested that the amide I, II, and III bands of SPI were altered by the glycation induced by TiO2 photocatalysis. Moreover, significant changes of secondary structure occurred in SPI-dextran conjugates. The α-helix, β-sheet, β-turns, and random coil were changed from approximately 10.6%, 37.9%, 12.9%, and 38.6% to 3.8%, 10.4%, 17.7%, and 68.8%, respectively, after treatment at photocatalytic power of 1000 W. In addition, SPI-dextran conjugates obtained by TiO2 photocatalysis treatment exhibited high hydroxyl radical scavenging activity and possessed increased reducing power. All data indicated that TiO2 photocatalysis was an efficient method for promoting protein-polysaccharide copolymerisation.

  2. Norisoboldine ameliorates DSS-induced ulcerative colitis in mice through induction of regulatory T cells in colons.

    Science.gov (United States)

    Lv, Qi; Qiao, Si-miao; Xia, Ying; Shi, Can; Xia, Yu-feng; Chou, Gui-xin; Wang, Zheng-tao; Dai, Yue; Wei, Zhi-feng

    2015-12-01

    Norisoboldine (NOR), the main active constituent of Radix Linderae, was previously demonstrated to ameliorate collagen-induced arthritis in rats through regulating the imbalance of T cells in intestines, which implied its therapeutic potential in inflammatory bowel disease. Here, we investigated the effect of NOR on ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) in mice. Results showed that NOR (20, 40mg/kg) markedly reduced the symptoms of colitis, the levels of IL-1β and TNF-α, and the activation of ERK, p38 MAPK and NF-κB-p65. NOR only slightly decreased the levels of IFN-γ and IL-17A in mouse colons, but it dramatically increased the level of IL-10 at both protein and mRNA grades. Consistently, NOR increased the number of CD4(+)CD25(+)Foxp3(+) Treg cells more obviously than it decreased that of CD4(+)IL-17(+) Th17 cells in mesenteric lymph nodes (MLNs) and colonic lamina proprias (LPs) of colitis mice, and promoted the expression of Foxp3 mRNA in colon tissues. It could facilitate the in vitro differentiation of Treg cells from naive T cells and promote the phosphorylations of Smad2/3 in colon tissues of colitis mice. On the other hand, NOR did not affect the expressions of homing receptors CCR9 and α4β7 in SPs, and homing ligands CCL25 and Madcam-1 in MLNs and colonic LPs, suggesting that the increase of Treg cells in colons by NOR was not due to gut homing. In conclusion, NOR can ameliorate DSS-induced UC in mice, and the mechanisms involve reduction of pro-inflammatory cytokines and selective induction of Treg cells in colons.

  3. Protein tyrosine phosphatase 1B deficiency ameliorates murine experimental colitis via the expansion of myeloid-derived suppressor cells.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available Protein tyrosine phosphatase 1B (PTP1B is a key molecule in modulating low-degree inflammatory conditions such as diabetes. The role of PTP1B in other chronic inflammations, however, remains unknown. Here, we report that PTP1B deficiency ameliorates Dextran Sulfate Sodium (DSS-induced murine experimental colitis via expanding CD11b(+Gr-1(+ myeloid-derived suppressor cells (MDSCs. Employing DSS-induced murine experimental colitis as inflammatory animal model, we found that, compared with wild-type littermates, PTP1B-null mice demonstrated greater resistance to DSS-induced colitis, as reflected by slower weight-loss, greater survival rates and decreased PMN and macrophage infiltration into the colon. The evidence collectively also demonstrated that the resistance of PTP1B-null mice to DSS-induced colitis is based on the expansion of MDSCs. First, PTP1B-null mice exhibited a greater frequency of MDSCs in the bone marrow (BM, peripheral blood and spleen when compared with wild-type littermates. Second, PTP1B levels in BM leukocytes were significantly decreased after cells were induced into MDSCs by IL-6 and GM-CSF, and the MDSC induction occurred more rapidly in PTP1B-null mice than in wild-type littermates, suggesting PTP1B as a negative regulator of MDSCs. Third, the adoptive transfer of MDSCs into mice with DSS-colitis significantly attenuated colitis, which accompanies with a decreased serum IL-17 level. Finally, PTP1B deficiency increased the frequency of MDSCs from BM cells likely through enhancing the activities of signal transducer and activator of transcription 3 (STAT3 and Janus kinase 2 (JAK2. In conclusion, our study provides the first evidences that PTP1B deficiency ameliorates murine experimental colitis via expanding MDSCs.

  4. Suspected nitrite poisoning in pigs caused by Capsella bursa-pastoris (L. Medik. ('herderstassie', shepherd's purse : case report

    Directory of Open Access Journals (Sweden)

    W.J. Wiese

    2001-07-01

    Full Text Available Nitrite poisoning in pigs was suspected when 4 of 18 pigs died in a piggery near Ellisras in the Northern Province. The pigs showed typical brownish discolouration of the blood at autopsy. It was established that they ingested vegetable tops and weeds from the adjacent garden as part of their daily ration. Of the available plants, only Capsella bursa-pastoris contained nitrites. The drinking water and some of the other plants tested positive for nitrates but not for nitrites. This is the first report of suspected nitrite poisoning in pigs caused by Capsella bursa-pastoris.

  5. Mitochondrial aldehyde dehydrogenase mediates vasodilator responses of glyceryl trinitrate and sodium nitrite in the pulmonary vascular bed of the rat.

    Science.gov (United States)

    Badejo, Adeleke M; Hodnette, Chris; Dhaliwal, Jasdeep S; Casey, David B; Pankey, Edward; Murthy, Subramanyam N; Nossaman, Bobby D; Hyman, Albert L; Kadowitz, Philip J

    2010-09-01

    It has been reported that mitochondrial aldehyde dehydrogenase (ALDH2) catalyzes the formation of glyceryl dinitrate and inorganic nitrite from glyceryl trinitrate (GTN), leading to an increase in cGMP and vasodilation in the coronary and systemic vascular beds. However, the role of nitric oxide (NO) formed from nitrite in mediating the response to GTN in the pulmonary vascular bed is uncertain. The purpose of the present study was to determine if nitrite plays a role in mediating vasodilator responses to GTN. In this study, intravenous injections of GTN and sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure under baseline and elevated tone conditions and decreases in systemic arterial pressure in response to GTN and sodium nitrite were attenuated by cyanamide, an ALDH2 inhibitor, whereas responses to the NO donor, sodium nitroprusside (SNP), were not altered. The decreases in pulmonary and systemic arterial pressure in response to GTN and SNP were not altered by allopurinol, an inhibitor of xanthine oxidoreductase, whereas responses to sodium nitrite were attenuated. GTN was approximately 1,000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures. These results suggest that ALDH2 plays an important role in the bioactivation of GTN and nitrite in the pulmonary and systemic vascular beds and that the reduction of nitrite to vasoactive NO does not play an important role in mediating vasodilator responses to GTN in the intact chest rat.

  6. Influence of nitrite accumulation on "Candidatus Accumulibacter" population structure and enhanced biological phosphorus removal from municipal wastewater.

    Science.gov (United States)

    Zeng, Wei; Li, Boxiao; Wang, Xiangdong; Bai, Xinlong; Peng, Yongzhen

    2016-02-01

    A modified University of Cape Town (MUCT) process was used to treat real municipal wastewater with low carbon to nitrogen ratio (C/N). To our knowledge, this is the first study where the influence of nitrite accumulation on "Candidatus Accumulibacter" clade-level population structure was investigated during nitritation establishment and destruction. Real time quantitative PCR assays were conducted using the polyphosphate kinase 1 gene (ppk1) as a genetic marker. Abundances of total "Candidatus Accumulibacter", the relative distributions and population structure of the five "Candidatus Accumulibacter" clades were characterized. Under complete nitrification, clade I using nitrate as electron acceptor was below 5% of total "Candidatus Accumulibacter". When the reactor was transformed into nitritation, clade I gradually disappeared. Clade IID using nitrite as electron acceptor for denitrifying phosphorus (P) removal was always the dominant "Candidatus Accumulibacter" throughout the operational period. This clade was above 90% on average in total "Candidatus Accumulibacter", even up to nearly 100%, which was associated with good performance of denitrifying P removal via nitrite pathway. The nitrite concentrations affected the abundance of clade IID. The P removal was mainly completed by anoxic P uptake of about 88%. The P removal efficiency clearly had a positive correlation with the nitrite accumulation ratio. Under nitritation, the P removal efficiency was 30% higher than that under complete nitrification, suggesting that nitrite was appropriate as electron acceptor for denitrifying P removal when treating carbon-limited wastewater. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Further studies on the effect of nitrogen dioxide on mast cells: The effect of the metabolite, nitrite

    Energy Technology Data Exchange (ETDEWEB)

    Fujimaki, Hidekazu (National Institute for Environmental Studies, Onogawa (Japan)); Ozawa, Masashi (The Jikei Univ. School of Medicine, Tokyo (Japan)); Bissonnette, E.; Befus, A.D. (Univ. of Calgary, Alberta (Canada))

    1993-05-01

    To evaluate the relationship between atmospheric nitrogen dioxide exposure and the development of allergic diseases, the effects of nitrite as a chemical product of inhaled nitrogen dioxide on mast cell functions were investigated. We have studied nitride-induced histamine release from two functionally distinct mast cell populations, namely peritoneal mast cells (PMC) and intestinal mucosal mast cells (IMMC) of Nippostrongylus brasiliensis-infected rats. High concentrations of nitrite alone (10, 20, and 50 mM) induced histamine release from IMMC, but not from PMC. Moreover, histamine release from PMC and IMMC stimulated with sensitizing antigen was significantly enhanced by pretreatment with 50 mM nitrite or nitrate. No differences in histamine release from nitrite-treated and control PMC were seen below 1 mM. To investigate the effect of nitrite on tumor cell cytotoxic activity, PMC were incubated with various concentrations of nitrite. Pretreatment with 5 and 50 mM nitrite markedly depressed tumor necrosis factor (TNF)-[alpha]-dependent natural cytotoxicity of PMC for the tumor target WEHI-164. Thus, high concentrations of nitrite enhanced mast cell histamine release, but depressed TNF-[alpha]-dependent cytotoxicity. However, low concentrations of nitrite (<1 mM) that would normally be produced by short-term atmospheric exposure to nitrogen dioxide may have no significant effects on mast cell functions. 27 refs., 3 figs., 1 tab.

  8. Study of Cobalt(III) Corrole as the Neutral Ionophore for Nitrite and Nitrate Detection via Polymeric Membrane Electrodes.

    Science.gov (United States)

    Yang, Si; Meyerhoff, Mark E

    2013-12-01

    Cobalt(III) 5, 10, 15-tris(4-tert-butylphenyl) corrole was synthesized and incorporated into plasticized poly(vinyl chloride) membranes and studied as a neutral carrier ionophore via potentiometry. This cobalt(III) complex has binding affinity to nitrite, and the resulting membrane electrode yields reversible and Nernstian response toward nitrite. Enhanced nitrite selectivity is observed over other anions, including lipophilic anions such as thiocyanate and perchlorate when an appropriate amount of lipophilic cationic sites are added to the membrane phase. Detection limit to nitrite is ca. 5 µM. Using tributylphosphate as the plasticizer with the cobalt(III) corrole species yields electrodes with enhanced nitrate selectivity.

  9. Use of Coffee Pulp and Minerals for Natural Soil Ameliorant

    Directory of Open Access Journals (Sweden)

    Pujiyanto Pujiyanto

    2007-05-01

    Full Text Available In coffee plantation, solid waste of coffee pulp is usually collected as heap nearby processing facilities for several months prior being used as compost. The practice is leading to the formation of odor and liquid which contaminate the environment. Experiments to evaluate the effect of natural soil ameliorant derived from coffee pulp and minerals were conducted at The Indonesian Coffee and Cocoa Research Institute in Jember, East Java. The experiments were intended to optimize the use of coffee pulp to support farming sustainability and minimize negative impacts of solid waste disposal originated from coffee cherry processing. Prior to applications, coffee pulp was hulled to organic paste. The paste was then mixed with 10% minerals (b/b. Composition of the minerals was 50% zeolite and 50% rock phosphate powder. The ameliorant was characterized for their physical and chemical properties. Agronomic tests were conducted on coffee and cocoa seedling. The experiments were arranged according to Randomized Completely Design with 2 factors, consisted of natural ameliorant and inorganic fertilizer respectively. Natural ameliorant derived from coffee pulp was applied at 6 levels: 0, 30, 60, 90, 120 and 150 g dry ameliorant/seedling of 3 kg soil, equivalent to 0, 1, 2, 3, 4 and 5% (b/b of ameliorant respectively. Inorganic fertilizer was applied at 2 levels: 0 and 2 g fertilizer/application of N-P-K compound fertilizer of 15-15-15 respectively. The inorganic fertilizer was applied 4 times during nursery of coffee and cocoa. The result of the experiment indicated that coffee pulp may be used as natural soil ameliorant. Composition of ameliorant of 90% coffee pulp and 10% of minerals has good physical and chemical characteristics for soil amelioration. The composition has high water holding capacity; cations exchange capacity, organic carbon and phosphorus contents which are favorable to increase soil capacity to support plant growth. Application of

  10. A novel fiber optic spectrophotometric determination of nitrite using Safranin O and cloud point extraction.

    Science.gov (United States)

    Filik, Hayati; Giray, Derya; Ceylan, Burak; Apak, Reşat

    2011-09-30

    A novel fiber optic spectrophotometric method for nitrite determination in different samples is suggested, based on the reaction of nitrite with Safranin O in acidic medium to form a diazo-safranin, which is subsequently coupled with pyrogallol in alkaline medium to form a highly stable, red azo dye, followed by cloud point extraction (CPE) using a mixed micelle of a nonionic surfactant, Triton X-114, with an anionic surfactant, sodium dodecyl sulphate (SDS). The reaction and extraction conditions (e.g., acidity for diazotization and alkalinity for pyrogallol coupling, and other reagent concentrations, time, and tolerance to other ions) were optimized. Linearity was obeyed in a concentration range up to 230 μg L(-1), and the detection limit of the method is 0.5 μg L(-1) of nitrite ion. The molar absorptivity for nitrite of the Safranin-diazonium salt (ɛ(610 nm) =4 × 10(3) L mol(-1)cm(-1)) existing in literature was greatly enhanced by pyrogallol coupling and CPE enrichment (ɛ(592 nm)=1.39 × 10(5) L mol(-1)cm(-1)). The method was applied to the determination of nitrite in tap water, lake water and milk samples with an optimal preconcentration factor of 20.

  11. A genetic screen reveals a periplasmic copper chaperone required for nitrite reductase activity in pathogenic Neisseria.

    Science.gov (United States)

    Jen, Freda E-C; Djoko, Karrera Y; Bent, Stephen J; Day, Christopher J; McEwan, Alastair G; Jennings, Michael P

    2015-09-01

    Under conditions of low oxygen availability, Neisseria meningitidis and Neisseria gonorrhoeae are able to respire via a partial denitrification pathway in which nitrite is converted to nitrous oxide. In this process, nitrite reductase (AniA), a copper (Cu)-containing protein converts nitrite to NO, and this product is converted to nitrous oxide by nitric oxide reductase (NorB). NorB also confers protection against toxic NO, and so we devised a conditional lethal screen, using a norB mutant, to identify mutants that were resistant to nitrite-dependent killing. After random-deletion mutagenesis of N. meningitidis, this genetic screen identified a gene encoding a Cu chaperone that is essential for AniA function, AccA. Purified AccA binds one Cu (I) ion and also possesses a second binding site for Cu (II). This novel periplasmic Cu chaperone (AccA) appears to be essential for provision of Cu ions to AniA of pathogenic Neisseria to generate an active nitrite reductase. Apart from the Neisseria genus, AccA is distributed across a wide range of environmental Proteobacteria species. © FASEB.

  12. Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jacob W.; Lam, Royce K.; Saykally, Richard J., E-mail: saykally@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Shih, Orion [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Rizzuto, Anthony M. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Prendergast, David [The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-08-28

    Nitrate and nitrite ions are of considerable interest, both for their widespread use in commercial and research contexts and because of their central role in the global nitrogen cycle. The chemistry of atmospheric aerosols, wherein nitrate is abundant, has been found to depend on the interfacial behavior of ionic species. The interfacial behavior of ions is determined largely by their hydration properties; consequently, the study of the hydration and interfacial behavior of nitrate and nitrite comprises a significant field of study. In this work, we describe the study of aqueous solutions of sodium nitrate and nitrite via X-ray absorption spectroscopy (XAS), interpreted in light of first-principles density functional theory electronic structure calculations. Experimental and calculated spectra of the nitrogen K-edge XA spectra of bulk solutions exhibit a large 3.7 eV shift between the XA spectra of nitrate and nitrite resulting from greater stabilization of the nitrogen 1s energy level in nitrate. A similar shift is not observed in the oxygen K-edge XA spectra of NO{sub 3}{sup −} and NO{sub 2}{sup −}. The hydration properties of nitrate and nitrite are found to be similar, with both anions exhibiting a similar propensity towards ion pairing.

  13. A sensitive fluorimetric method for determination of trace amounts of nitrite based on luminescence energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lun, E-mail: wanglun@mail.ahnu.edu.c [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Chen Jingguo; Chen Hongqi; Zhou Cailing; Ling Bo; Fu Jie [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2011-01-15

    An efficient luminescence energy transfer (LET) system based on terbium(III)-sodium hexametaphosphate (Tb/SHMP) chelates as donor and 4-((4-(2-aminoethylamino)naphthalen-1-yl)diazenyl)benzenesulfonic acid dihydrochloride (ANDBS) as acceptor was developed for sensitive determination of trace nitrite. Stable and strong fluorescence Tb/SHMP chelates were prepared in aqueous solution. Based on Griess Reaction, ANDBS was generated by the quantitative reaction of nitrite, sulfanilamide and N-(1-naphtyl)-ethylenediamine dihydrochloride (N1NED). The degree of the overlap was effective for LET between the emission spectrum of Tb/SHMP chelates and the absorption spectrum of ANDBS. Based on the luminescence intensity quenching of Tb/SHMP chelates in proportion to the trace amounts of nitrite, a new assay for the selective and sensitive determination of nitrite was developed. Under the optimum conditions, the linear calibration graph was obtained with a linear range of 0.00040-0.20 {mu}g mL{sup -1} (R=0.99657). The detection limit of NO{sub 2}{sup -} was 0.00010 {mu}g mL{sup -1} (R=0.99657). The method was applied successfully to the determination of nitrite for synthetic samples.

  14. Microbial mediated iron redox cycling in Fe (hydr)oxides for nitrite removal.

    Science.gov (United States)

    Lu, Yongsheng; Xu, Lu; Shu, Weikang; Zhou, Jizhi; Chen, Xueping; Xu, Yunfeng; Qian, Guangren

    2017-01-01

    Nitrite, at an environmentally relevant concentration, was significantly reduced with iron (hydr)oxides mediated by Shewanella oneidensis MR-1. The average nitrite removal rates of 1.28±0.08 and 0.65±0.02(mgL(-1))h(-1) were achieved with ferrihydrite and magnetite, respectively. The results showed that nitrite removal was able to undergo multiple redox cycles with iron (hydr)oxides mediated by Shewanella oneidensis MR-1. During the bioreduction of the following cycles, biogenic Fe(II) was subsequently chemically oxidized to Fe(III), which is associated with nitrite reduction. There was 11.18±1.26mgL(-1) of NH4(+)-N generated in the process of redox cycling of ferrihydrite. Additionally, results obtained by using X-ray diffraction showed that ferrihydrite and magnetite remained mainly stable in the system. This study indicated that redox cycling of Fe in iron (hydr)oxides was a potential process associated with NO2(-)-N removal from solution, and reduced most nitrite abiotically to gaseous nitrogen species.

  15. Spectrofluorimetric determination of trace nitrite with o-phenylenediamine enhanced by hydroxypropyl-β-cyclodextrin

    Science.gov (United States)

    Guo, Yu-Xian; Zhang, Qing-Feng; Shangguang, Xincheng; Zhen, Guodong

    2013-01-01

    A simple and sensitive spectrofluorimetric method was developed for the determination of nitrite in environmental and food samples. The method was based on the selective reaction of o-phenylenediamine with nitrite in acidic medium to form benzotriazole, which exhibited strong fluorescence at 568 nm with excitation at 420 nm in alkaline medium. The detection limit and sensitivity of the proposed method were improved by hydroxypropyl-β-cyclodextrin through complexation. The linear calibration range for nitrite was 0.04-0.8 μg mL-1 with a detection limit of 13.6 ng mL-1 (S/N = 3.29). The relative standard deviation for ten determinations of 0.1 and 0.4 μg mL-1 nitrite were 1.38% and 2.01%, respectively. Twenty-eight coexistent ions were examined, and no serious interference for most of ions was observed. The proposed method was successfully applied for the determination of nitrite in the water, sausage and soil samples with recoveries of 95.5-108.5%. The results were in good agreement with the recommended AOAC method.

  16. Effects of nitrite on phosphate uptake in anaerobic-oxic process

    Institute of Scientific and Technical Information of China (English)

    LI Jie; XIONG Biyong; ZHANG Shude; YANG Hong; ZHANG Jie

    2007-01-01

    An anaerobic-oxic(A/O)biological phosphorus removal reactor was operated to study the effect of nitrite on phosphate uptake.The phosphorus uptake profile was determined under different operating conditions.The results indicated that in addition to oxygen and nitrate(DPBNa,nitrate denitrifying phosphorus removal),to some extent,nitrite could also serve as an electron acceptor to achieve nitrite denitrifying phosphorus removal(DPBNi).The quantity and rate of phosphorus uptake of DPBNi,however,were evidently lower than that of DPBNa.The experiment results revealed that nitrite would bring toxic action to phosphate accumulating organisms(PAOs)when NO2- -N≥93]7 mg/L.The nitrite existing in the anoxic reactor made no difference to the quantity and rate of denitrifying phosphorus removal,but it could reduce the consumption of nitrate.Moreover,the data showed that the aerobic phosphate uptake of DPBNi was lower than that of anaerobic phosphorus-released sludge in a traditional A/O process.However,there was not much difference between these two kinds of sludge in terms of the total phosphorus uptake quantity and the effluent quality.

  17. Nitrite accumulation during denitrification depends on the carbon quality and quantity in wastewater treatment with biofilters.

    Science.gov (United States)

    Rocher, Vincent; Laverman, Anniet M; Gasperi, Johnny; Azimi, Sam; Guérin, Sabrina; Mottelet, Stéphane; Villières, Thierry; Pauss, André

    2015-07-01

    This study aims to understand the mechanisms of nitrite appearance during wastewater denitrification by biofilters, focusing on the role of the carbon source. Experiments were carried out at lab-scale (batch tests) and full-scale plant (Parisian plant, capacities of 240,000 m(3) day(-1)). Results showed that the nature of the carbon source affects nitrite accumulation rates. This accumulation is low, 0.05 to 0.10 g N-NO2(-) per g N-NO3(-) eliminated, for alcohols such as methanol, ethanol, or glycerol. The utilization of glycerol leads to fungal development causing clogging of the biofilters. This fungal growth and consequent clogging exclude this carbon source, with little nitrite accumulation, as carbon source for denitrification. Whatever the carbon source, the C/N ratio in the biofilter plays a major role in the appearance of residual nitrite; an optimal C/N ratio from 3.0 to 3.2 allows a complete denitrification without any nitrite accumulation.

  18. Laboratory study on factors influencing nitrogen removal in marble chip biofilters incorporating nitritation and anammox.

    Science.gov (United States)

    Tao, Wendong; Wen, Jianfeng; Norton, Christopher

    2011-01-01

    It remains challenging to integrate nitritation and anammox in ecologically engineered treatment systems such as passive biofilters that are packed with natural materials and have low energy inputs. This study explored the factors influencing nitritation-anammox through parallel operation of two laboratory-scale biofilters packed with large and small marble chips respectively. Clean marble chips (mainly CaCO3) had an alkalinity dissolution rate of 130 mg CaCO3/kg marble d when water pH approached 6.5. Marble chips effectively increased water pH and provided sufficient alkalinity to support nitritation-anammox in the biofilters. Ammonium and total nitrogen removal decreased by 47 and 26%, respectively, when nutrients were not amended to influent. An influent nitrite concentration above 8.9 mg N/L could inhibit anammox in thin biofilms of biofilters. Nitritation-anammox was enhanced with a hydraulic retention time of 2 d relative to 7 d, likely due to enhanced air entrainment. Size of marble chips rarely made a significant difference in nitrogen removal, possibly due to sufficient surface area available for bacterial attachment and alkalinity dissolution.

  19. Near-fatal methemoglobinemia after recreational inhalation of amyl nitrite aerosolized with a compressed gas blower.

    Science.gov (United States)

    Lin, Chih-Hao; Fang, Cheng-Chung; Lee, Chien-Chang; Ko, Patrick Chow-In; Chen, Wen-Jone

    2005-11-01

    Adverse effects associated with recreational inhalation of nitrites are usually mild and rarely life-threatening. We report a rare case of near-fatal methemoglobinemia after inhalation of amyl nitrite after aerosolizing the liquid using a compressed gas blower designed to clean photographic equipment that employed hydrofluoroalkane-134a as a propellant. A 31-year-old previously healthy male became dyspneic and fainted soon after the recreational inhalation of amyl nitrite aerosolized using a compressed gas blower. He was brought to the emergency department with severe cyanotic appearance and profound shock. Oxygen saturation was 82%, unresponsive to oxygen supply. His methemoglobin blood level was 52.2%. After 100 mg of methylene blue (2 mg/kg body weight) was administered intravenously, he recovered consciousness, and dyspnea and cyanosis subsided gradually. This case illustrates the extraordinary hazard of the use of a compressed gas blower in the recreational inhalation of nitrites. Prompt recognition and rapid antidotal treatment may adequately correct near-fatal overdose associated with recreational use of amyl nitrite.

  20. Long-term nitritation performance of ammonium-rich landfill leachate☆

    Institute of Scientific and Technical Information of China (English)

    Hongwei Sun; Xintao L; Yongzhen Peng; Shuying Wang; Juan Ma

    2015-01-01

    This study presents a biological system combined upflow anaerobic sludge bed (UASB) with sequencing batch reactor (SBR) to treat ammonium-rich landfill leachate. The start-up and operation of the nitritation at low temperatures were investigated. The synergetic interaction of free ammonia (FA) inhibition on nitrite-oxidizing bacteria (NOB) and process control was used to achieve nitritation in the SBR. It is demonstrated that nitritation was successful y started up in the SBR at low temperatures (14.0 °C–18.2 °C) by using FA inhibition coupled with process control, and then was maintained for 482 days at normal/low temperature. Although ammonia-oxidizing bacteria (AOB) and NOB co-existed within bacterial clusters in the SBR sludge, AOB were confirmed to be dominant nitrifying population species by scanning electron microscopic (SEM) observation and fluorescence in situ hybridization (FISH) analysis. This confirmation not only emphasized that cultivating the appropriate bacteria is essential for achieving stable nitritation performance, but it also revealed that NOB activity was strongly inhibited by FA rather than being eliminated altogether from the system.

  1. A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples

    Directory of Open Access Journals (Sweden)

    Cherian Tom

    2006-01-01

    Full Text Available A selective and rapid spectrophotometric method for the determination of nitrite is presented. It is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. The method obeys Beer's law in the concentration range of 0.5-16 µg mL-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 µg mL-1 of nitrite with ethylcyanoacetate. The molar absorptivity and Sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 X 10(4 L mol-1cm-1, 0.98 X 10-2 µg cm-2 and 1.21 X 10(4 L mol-1 cm-1, 0.98 X 10-2 µg cm-2 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The method was successfully applied to the determination of nitrite in various water samples and soil samples.

  2. Molecular characterization of Lactobacillus plantarum DMDL 9010, a strain with efficient nitrite degradation capacity.

    Science.gov (United States)

    Fei, Yong-tao; Liu, Dong-mei; Luo, Tong-hui; Chen, Gu; Wu, Hui; Li, Li; Yu, Yi-gang

    2014-01-01

    Nitrites commonly found in food, especially in fermented vegetables, are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. A Lactobacillus strain (Lactobacillus sp. DMDL 9010) was previously isolated from fermented vegetables by our group, and is not yet fully characterized. A number of phenotypical and genotypical approaches were employed to characterize Lactobacillus sp. DMDL 9010. Its nitrite degradation capacity was compared with four other Lactobacillus strains, including Lactobacillus casei subsp. rhamnosus 719, Lactobacillus delbrueckii subsp. bulgaricu 1.83, Streptococcus thermophilus 1.204, and lactobacillus plantarum 8140, on MRS medium. Compared to these four Lactobacillus strains, Lactobacillus sp. DMDL 9010 had a significantly higher nitrite degradation capacity (PLactobacillus sp. DMDL 9010 was identified as either Lactobacillus plantarum or Lactobacillus pentosus. To further identify this strain, the flanking regions (922 bp and 806 bp upstream and downstream, respectively) of the L-lactate dehydrogenase 1 (L-ldh1) gene were amplified and sequenced. Lactobacillus sp. DMDL 9010 had 98.92 and 76.98% sequence identity in the upstream region with L. plantarum WCFS1 and L. pentosus IG1, respectively, suggesting that Lactobacillu sp. DMDL 9010 is an L. plantarum strain. It was therefore named L. plantarum DMDL 9010. Our study provides a platform for genetic engineering of L. plantarum DMDL 9010, in order to further improve its nitrite degradation capacity.

  3. Nitrite is a positive modulator of the Frank-Starling response in the vertebrate heart.

    Science.gov (United States)

    Angelone, Tommaso; Gattuso, Alfonsina; Imbrogno, Sandra; Mazza, Rosa; Tota, Bruno

    2012-06-01

    Evidence from both mammalian and nonmammalian vertebrates indicates that intracardiac nitric oxide (NO) facilitates myocardial relaxation, ventricular diastolic distensibility, and, consequently, the Frank-Starling response, i.e., the preload-induced increase of cardiac output. Since nitrite ion (NO(2)(-)), the major storage pool of bioactive NO, recently emerged as a cardioprotective endogenous modulator, we explored its influence on the Frank-Starling response in eel, frog, and rat hearts, used as paradigms of fish, amphibians, and mammals, respectively. We demonstrated that, like NO, exogenous nitrite improves the Frank-Starling response in all species, as indicated by an increase of stroke volume and stroke work (eel and frog) and of left ventricular (LV) pressure and LVdP/dt max (rat), used as indexes of inotropism. Unlike in frog and rat, in eel, the positive influence of nitrite appeared to be dependent on NO synthase inhibition. In all species, the effect was sensitive to NO scavengers, independent on nitroxyl anion, and mediated by a cGMP/PKG-dependent pathway. Moreover, the nitrite treatment increased S-nitrosylation of lower-molecular-weight proteins in cytosolic and membrane fractions. These results suggest that nitrite acts as a physiological source of NO, modulating through different species-specific mechanisms, the stretch-induced intrinsic regulation of the vertebrate heart.

  4. Acetalated dextran is a chemically and biologically tunable material for particulate immunotherapy.

    Science.gov (United States)

    Broaders, Kyle E; Cohen, Joel A; Beaudette, Tristan T; Bachelder, Eric M; Fréchet, Jean M J

    2009-04-07

    Materials that combine facile synthesis, simple tuning of degradation rate, processability, and biocompatibility are in high demand for use in biomedical applications. We report on acetalated dextran, a biocompatible material that can be formed into microparticles with degradation rates that are tunable over 2 orders of magnitude depending on the degree and type of acetal modification. Varying the degradation rate produces particles that perform better than poly(lactic-co-glycolic acid) and iron oxide, two commonly studied materials used for particulate immunotherapy, in major histocompatibility complex class I (MHC I) and MHC II presentation assays. Modulating the material properties leads to antigen presentation on MHC I via pathways that are dependent or independent of the transporter associated with antigen processing. To the best of our knowledge, this is the only example of a material that can be tuned to operate on different immunological pathways while maximizing immunological presentation.

  5. Sodium arsenite reduces severity of dextran sulfate sodium-induced ulcerative colitis in rats

    Institute of Scientific and Technical Information of China (English)

    Joshua J. MALAGO; Hortensia NONDOLI

    2008-01-01

    The histopathological features and the associated clinical findings of ulcerative colitis (UC) are due to persistent inflammatory response in the colon mucosa. Interventions that suppress this response benefit UC patients. We tested whether sodium arsenite (SA) benefits rats with dextran sulfate sodium (DSS)-colitis. The DSS-colitis was induced by 5% DSS in drinking water. SA (10 mg/kg; intraperitoneally) was given 8 h before DSS treatment and then every 48 h for 3 cycles of 7,14 or 21 d. At the end of each cycle rats were sacrificed and colon sections processed for histological examination. DSS induced diarrhea, loose stools, hemoccult positive stools, gross bleeding, loss of body weight, loss of epithelium, crypt damage, depletion of goblet cells and infiltration of inflammatory cells. The severity of these changes increased ir the order of Cycles 1,2 and 3. Treatment of rats with SA significantly reduced this severity and improved the weight gain.

  6. Concentration dependent effects of dextran on the physical properties of acid milk gels.

    Science.gov (United States)

    Mende, Susann; Peter, Michaela; Bartels, Karin; Dong, Tingting; Rohm, Harald; Jaros, Doris

    2013-11-06

    The effect of dextran from Leuconostoc mesenteroides (DEX500), added to milk prior to acidification with glucono-δ-lactone (GDL) or Streptococcus thermophilus DSM20259, was studied with respect to polysaccharide concentration. The incorporation of 5-30 g/kg DEX500 significantly affected gelation behavior. Increasing DEX500 concentrations resulted in a linear increase of gel stiffness (GDL gels: R(2)=0.96; microbial acidification: R(2)=0.94; Pgels without polysaccharide. The respective stirred gels depicted a significant reduction in syneresis, which decreased from 30.4% (0 g/kg DEX500) to 22.0% (30 g/kg DEX500) for chemically acidified gels after 1 d of storage. Physical characteristics of DEX500 in aqueous solution were helpful to explain its behavior in the complex system milk.

  7. Impaired skin barrier function in mice with colon carcinoma induced by azoxymethane and dextran sodium sulfate.

    Science.gov (United States)

    Yokoyama, Satoshi; Hiramoto, Keiichi; Koyama, Mayu; Ooi, Kazuya

    2015-01-01

    We have previously reported that impaired skin barrier function was induced by small intestinal injury in mice. Therefore, we postulated that other intestinal diseases might also influence skin barrier function. In this study, we evaluated the skin barrier function of hairless mice with colon carcinoma that was induced by azoxymethane (AOM) and dextran sodium sulfate (DSS). In mice treated with these drugs, we observed elevated transepidermal water loss and reduced skin hydration levels, compared to those in the control mice. In addition, plasma nitrogen di/trioxide (NO2(-)/NO3(-)) levels were significantly elevated, and expression of type I collagen was significantly reduced in the treated mice, compared to those in control. These results suggest that impaired skin barrier function occurs in mice when colon carcinoma is present.

  8. Microstructured dextran hydrogels for burst-free sustained release of PEGylated protein drugs.

    Science.gov (United States)

    Bae, Ki Hyun; Lee, Fan; Xu, Keming; Keng, Choong Tat; Tan, Sue Yee; Tan, Yee Joo; Chen, Qingfeng; Kurisawa, Motoichi

    2015-09-01

    Hydrogels have gained significant attention as ideal delivery vehicles for protein drugs. However, the use of hydrogels for protein delivery has been restricted because their porous structures inevitably cause a premature leakage of encapsulated proteins. Here, we report a simple yet effective approach to regulate the protein release kinetics of hydrogels through the creation of microstructures, which serve as a reservoir, releasing their payloads in a controlled manner. Microstructured dextran hydrogels enable burst-free sustained release of PEGylated interferon over 3 months without compromising its bioactivity. These hydrogels substantially extend the circulation half-life of PEGylated interferon, allowing for less frequent dosing in a humanized mouse model of hepatitis C. The present approach opens up possibilities for the development of sustained protein delivery systems for a broad range of pharmaceutical and biomedical applications.

  9. Protein adsorption and transport in dextran-modified ion-exchange media. II. Intraparticle uptake and column breakthrough.

    Science.gov (United States)

    Bowes, Brian D; Lenhoff, Abraham M

    2011-07-22

    Protein transport behavior was compared for the traditional SP Sepharose Fast Flow and the dextran-modified SP Sepharose XL and Capto S resins. Examination of the dynamic binding capacities (DBCs) revealed a fundamental difference in the balance between transport and equilibrium capacity limitations when comparing the two resin classes, as reflected by differences in the locations of the maximum DBCs as a function of salt. In order to quantitatively compare transport behavior, confocal microscopy and batch uptake experiments were used to obtain estimates of intraparticle protein diffusivities. For the traditional particle, such diffusivity estimates could be used to predict column breakthrough behavior accurately. However, for the dextran-modified media, neither the pore- nor the homogeneous-diffusion model was adequate, as experimental dynamic binding capacities were consistently lower than predicted. In examining the shapes of breakthrough curves, it was apparent that the model predictions failed to capture two features observed for the dextran-modified media, but never seen for the traditional resin. Comparison of estimated effective pore diffusivities from confocal microscopy and batch uptake experiments revealed a discrepancy that led to the hypothesis that protein uptake in the dextran-modified resins could occur with a shrinking-core-like sharp uptake front, but with incomplete saturation. The reason for the incomplete saturation is speculated to be that protein initially fills the dextran layer with inefficient packing, but can rearrange over time to accommodate more protein. A conceptual model was developed to account for the partial shrinking-core uptake to test whether the physical intuition led to predictions consistent with experimental behavior. The model could correctly reproduce the two unique features of the breakthrough curves and, in sample applications, parameters found from the fit of one breakthrough curve could be used to adequately match

  10. Higher fecal bile acid hydrophobicity is associated with exacerbation of dextran sodium sulfate colitis in mice.

    Science.gov (United States)

    Stenman, Lotta K; Holma, Reetta; Forsgård, Richard; Gylling, Helena; Korpela, Riitta

    2013-11-01

    Increased luminal bile acid hydrophobicity is associated with cytotoxicity and has been suggested to contribute to gut barrier dysfunction. The aim of this study was to compare 2 high-fat diets and a low-fat diet as to whether they modify fecal bile acid profile and hydrophobicity and/or susceptibility to dextran sodium sulfate (DSS) colitis in C57Bl/6J mice. Control and DSS-Control groups received a low-fat control diet [5.5% of total energy (E%) soy oil, 4.5 E% lard], and the DSS-Lard (5.5 E% soy oil, 54.5 E% lard) and DSS-Fish oil (5.5 E% soy oil, 27.2 E% lard and 27.2% menhaden oil) groups received high-fat diets. Feces for bile acid analysis were collected after 3-wk feeding, followed by induction of dextran DSS colitis (2 d 5% DSS in drinking water + 2 d tap water). Fecal bile acid hydrophobicity was elevated 76% in the lard group (P = 0.051) and 122% in the fish oil group (P = 0.001) compared with control, indicating potentially increased cytotoxicity. DSS caused severe colitis symptoms, evaluated as rectal bleeding, whereas all the controls were symptom free. The median symptom scores were: DSS-Control, 2.3 (IQR = 0.6, 3.0); DSS-Lard, 0.3 (IQR = 0, 2.3); and DSS-Fish oil, 2.4 (IQR = 1.9, 2.8). The only differences were DSS-Control vs. control (P fecal bile acid hydrophobicity (Spearman's ρ = 0.43; P = 0.028) and fecal deoxycholic acid concentration (Spearman's ρ = 0.39; P = 0.048). These results suggest that luminal bile acid modification, induced by altered dietary fat composition, may alter susceptibility to DSS colitis.

  11. Dextran coated bismuth-iron oxide nanohybrid contrast agents for computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Naha, Pratap C; Zaki, Ajlan Al; Hecht, Elizabeth; Chorny, Michael; Chhour, Peter; Blankemeyer, Eric; Yates, Douglas M; Witschey, Walter R T; Litt, Harold I; Tsourkas, Andrew; Cormode, David P

    2014-12-14

    Bismuth nanoparticles have been proposed as a novel CT contrast agent, however few syntheses of biocompatible bismuth nanoparticles have been achieved. We herein report the synthesis of composite bismuth-iron oxide nanoparticles (BION) that are based on a clinically approved, dextran-coated iron oxide formulation; the particles have the advantage of acting as contrast agents for both CT and MRI. BION were synthesized and characterized using various analytical methods. BION CT phantom images revealed that the X-ray attenuation of the different formulations was dependent upon the amount of bismuth present in the nanoparticle, while T2-weighted MRI contrast decreased with increasing bismuth content. No cytotoxicity was observed in Hep G2 and BJ5ta cells after 24 hours incubation with BION. The above properties, as well as the yield of synthesis and bismuth inclusion efficiency, led us to select the Bi-30 formulation for in vivo experiments, performed in mice using a micro-CT and a 9.4 T MRI system. X-ray contrast was observed in the heart and blood vessels over a 2 hour period, indicating that Bi-30 has a prolonged circulation half-life. Considerable signal loss in T2-weighted MR images was observed in the liver compared to pre-injection scans. Evaluation of the biodistribution of Bi-30 revealed that bismuth is excreted via the urine, with significant concentrations found in the kidneys and urine. In vitro experiments confirmed the degradability of Bi-30. In summary, dextran coated BION are biocompatible, biodegradable, possess strong X-ray attenuation properties and also can be used as T2-weighted MR contrast agents.

  12. Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the effect of Scutellariae Radix extract (SRE) on ulcerative colitis (UC) in rats induced by dextran-sulfate sodium (DSS).METHODS: Colitis was induced in male Sprague-Dawley (SD) rats (170-180 g) by 4% dextran sulfate sodium (DSS, wt/v; MW 54000) in drinking water for 8 d. The treated rats received 4% DSS and SRE orally (100 mg/kg per day). Control rats received either tap water or SRE only. Macroscopic assessment which included body weight changes, fecal occult blood and stool consistency were determined daily. At the appointed time, the rats were sacrificed and the entire colons were removed. The colon length and the myeloperoxidase (MPO) activity were measured. The severity of colitis was graded by morphological and histological assessments. The ion transport activity of the colonic mucosa was assessed by electrophysiological technique. RESULTS: Rats treated with oral administration of 4% DSS regularly developed clinical and macroscopic signs of colitis. Treatment with SRE relieved the symptoms, including the reduction in body weight, shortening and ulceration of the colon. Administration of SRE also significantly reduced the histological damage induced by DSS. Moreover, the Isc responses of the colonic mucosa to forskolin were suppressed after the induction of colitis. The stimulated ion transport activity of DSS-rats treated with SRE displayed significant improvement in the secretory responsiveness.CONCLUSION: SRE was effective in treating acute DSS -induced ulcerative colitis, as gauged by reduced clinical disease, improved macroscopic and histological damage scores, and enhanced recovery of normal colonic secretory function.

  13. Over-Expression of CD200 Protects Mice from Dextran Sodium Sulfate Induced Colitis

    Science.gov (United States)

    Chen, Zhiqi; Yu, Kai; Zhu, Fang; Gorczynski, Reginald

    2016-01-01

    Background and aim CD200:CD200 receptor (CD200R) interactions lead to potent immunosuppression and inhibition of autoimmune inflammation. We investigated the effect of "knockout"of CD200 or CD200R, or over-expression of CD200, on susceptibility to dextran sodium sulfate (DSS)—induced colitis, a mouse model of inflammatory bowel disease (IBD). Methods Acute or chronic colitis was induced by administration of dextran sodium sulfate (DSS) in four groups of age-matched C57BL/6 female mice: (1) CD200-transgenic mice (CD200tg); (2) wild-type (WT) mice; (3) CD200 receptor 1-deficient (CD200R1KO) mice; and (4) CD200-deficient (CD200KO) mice. The extent of colitis was determined using a histological scoring system. Colon tissues were collected for quantitative RT-PCR and Immunohistochemical staining. Supernatants from colonic explant cultures and mononuclear cells isolated from colonic tissue were used for ELISA. Results CD200KO and CD200R1KO mice showed greater sensitivity to acute colitis than WT mice, with accelerated loss of body weight, significantly higher histological scores, more severe infiltration of macrophages, neutrophils and CD3+ cells, and greater expression of macrophage-derived inflammatory cytokines, whose production was inhibited in vitro (in WT/CD200KO mouse cells) by CD200. In contrast, CD200tg mice showed less sensitivity to DSS compared with WT mice, with attenuation of all of the features seen in other groups. In a chronic colitis model, greater infiltration of Foxp3+ regulatory T (Treg) cells was seen in the colon of CD200tg mice compared to WT mice, and anti-CD25 mAb given to these mice attenuated protection. Conclusions The CD200:CD200R axis plays an immunoregulatory role in control of DSS induced colitis in mice. PMID:26841120

  14. Preparation and characterisation of Dextran-70 hydrogel for controlled release of praziquantel

    Directory of Open Access Journals (Sweden)

    Flávio dos Santos Campos

    2013-03-01

    Full Text Available A hydrogel was developed from 70 kDa dextran (DEX-70 and praziquantel (PZQ incorporated as a model drug. Biopharmaceutical properties, such as solubility and dissolution rate, were analysed in the design of the hydrogel. Furthermore, the hydrogel was also characterized by IR spectroscopy and DSC. Tests of the swelling rate showed that the hydrogel swelled slowly, albeit faster than the rate for the free polymer. In dissolution tests, the hydrogel released the drug slowly and continuously. This slow release was similar to that observed in the swelling tests and resulted in controlled release of the drug. Thus, this dextran is a suitable polymer for the development of hydrogels as vehicles for the controlled release of drugs.Um hidrogel foi desenvolvido a partir de dextrano 70 kDa (DEX-70 e praziquantel incorporado (PZQ como fármaco modelo. Propriedades biofarmacêuticas, como solubilidade e velocidade de dissolução, foram analisadas no desenvolvimento do hidrogel. Além disso, o hidrogel também foi caracterizado por espectroscopia na região do infravermelho e calorimetria diferencial exploratória (DSC. Testes da taxa de intumescimento mostraram que o hidrogel intumesce lentamente, embora tenha sido mais rápido do que a taxa do polímero livre. Nos testes de dissolução, o hidrogel liberou o fármaco lenta e continuamente. Esta liberação lenta foi semelhante a observada nos testes de intumescimento e resultou em uma liberação controlada do fármaco. Assim, o dextrano 70 kDa é um polímero adequado para o desenvolvimento de hidrogéis como veículos para a liberação controlada de fármacos.

  15. Papillomavirus microbicidal activities of high-molecular-weight cellulose sulfate, dextran sulfate, and polystyrene sulfonate.

    Science.gov (United States)

    Christensen, N D; Reed, C A; Culp, T D; Hermonat, P L; Howett, M K; Anderson, R A; Zaneveld, L J

    2001-12-01

    The high-molecular-weight sulfated or sulfonated polysaccharides or polymers cellulose sulfate, dextran sulfate, and polystyrene sulfonate were tested for microbicidal activity against bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 11 (HPV-11) and type 40 (HPV-40). In vitro assays included the BPV-1-induced focus-forming assay and transient infection of human A431 cells with HPVs. The compounds were tested for microbicidal activity directly by preincubation with virus prior to addition to cell cultures and indirectly by addition of virus to compound-treated cells and to virus-coated cells to test inactivation of the virus after virus-cell binding. The data indicated that all three compounds showed direct microbicidal activity with 50% effective concentrations between 10 to 100 microg/ml. These concentrations were nontoxic to cell cultures for both assays. When a clone of C127 cells was tested for microbicidal activity, approximately 10-fold-less compound was required to achieve a 50% reduction in BPV-1-induced foci than for the uncloned parental C127 cells. Pretreatment of cells with compound prior to addition of virus also demonstrated strong microbicidal activity with dextran sulfate and polystyrene sulfonate, but cellulose sulfate required several orders of magnitude more compound for virus inactivation. Polystyrene sulfonate prevented subsequent infection of HPV-11 after virus-cell binding, and this inactivation was observed up to 4 h after addition of virus. These data indicate that the polysulfated and polysulfonated compounds may be useful nontoxic microbicidal compounds that are active against a variety of sexually transmitted disease agents including papillomaviruses.

  16. Ameliorated GA approach for base station planning

    Science.gov (United States)

    Wang, Andong; Sun, Hongyue; Wu, Xiaomin

    2011-10-01

    In this paper, we aim at locating base station (BS) rationally to satisfy the most customs by using the least BSs. An ameliorated GA is proposed to search for the optimum solution. In the algorithm, we mesh the area to be planned according to least overlap length derived from coverage radius, bring into isometric grid encoding method to represent BS distribution as well as its number and develop select, crossover and mutation operators to serve our unique necessity. We also construct our comprehensive object function after synthesizing coverage ratio, overlap ratio, population and geographical conditions. Finally, after importing an electronic map of the area to be planned, a recommended strategy draft would be exported correspondingly. We eventually import HongKong, China to simulate and yield a satisfactory solution.

  17. A natural flavonoid glucoside icariin inhibits Th1 and Th17 cell differentiation and ameliorates experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Shen, Ruile; Deng, Wenjing; Li, Chun; Zeng, Guangwei

    2015-02-01

    Multiple sclerosis (MS) is an autoimmune disease that is characterized by recurrent episodes of T cell-mediated immune attack on central nervous system (CNS) myelin, leading to axon damage and progressive disability. Icariin, a natural flavonoid glucoside isolated from plants in the Epimedium family, has been proved to have various pharmacological activities. However, the effect of icariin on experimental autoimmune encephalomyelitis (EAE) has never been investigated. In our current study, we found that icariin treatment leads to alleviated inflammatory infiltration and reduced blood-brain barrier leakage (BBB) of the paracellular tracer (FITC-dextran) in EAE. Mice that received icariin-treated T cells also displayed lower EAE scores and better clinical recovery from EAE. Icariin administration suppresses the frequencies of Th1 and Th17 cells in the splenocytes and lymph node cells. Icariin-treated mice also show lower frequency of Th17 cells in CNS mononuclear cells. The effect of icariin on Th1 and Th17 cell differentiation may be mediated via modulation of dendritic cells (DCs). Furthermore, icariin suppresses the proliferation of T cells and the differentiation of Th1 and Th17 cells in vitro. In conclusion, icariin ameliorates EAE and this was associated with suppressed Th1 and Th17 cell differentiation. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Eggshell membrane powder ameliorates intestinal inflammation by facilitating the restitution of epithelial injury and alleviating microbial dysbiosis

    Science.gov (United States)

    Jia, Huijuan; Hanate, Manaka; Aw, Wanping; Itoh, Hideomi; Saito, Kenji; Kobayashi, Shoko; Hachimura, Satoshi; Fukuda, Shinji; Tomita, Masaru; Hasebe, Yukio; Kato, Hisanori

    2017-01-01

    Gut microbiota is an essential factor in the shaping of intestinal immune system development and driving inflammation in inflammatory bowel disease (IBD). We report the effects and microbe-host interactions underlying an intervention using fine powder of eggshell membrane (ESM) against IBD. ESM attenuated lipopolysaccharide-induced inflammatory cytokine production and promoted the Caco-2 cell proliferation by up-regulating growth factors in vitro. In a murine model of dextran sodium sulphate-induced colitis, ESM significantly suppressed the disease activity index and colon shortening. These effects were associated with significant ameliorations of gene expressions of inflammatory mediators, intestinal epithelial cell proliferation, restitution-related factors and antimicrobial peptides. Multifaceted integrated omics analyses revealed improved levels of energy metabolism-related genes, proteins and metabolites. Concomitantly, cecal metagenomic information established an essential role of ESM in improving dysbiosis characterized by increasing the diversity of bacteria and decreasing absolute numbers of pathogenic bacteria such as Enterobacteriaceae and E. coli, as well as in the regulation of the expansion of Th17 cells by suppressing the overgrowth of segmented filamentous bacteria. Such modulations have functional effects on the host; i.e., repairing the epithelium, regulating energy requirements and eventually alleviating mucosal inflammation. These findings are first insights into ESM’s modulation of microbiota and IBD suppression, providing new perspectives on the prevention/treatment of IBD. PMID:28272447

  19. Colonic gene silencing using siRNA-loaded calcium phosphate/PLGA nanoparticles ameliorates intestinal inflammation in vivo.

    Science.gov (United States)

    Frede, Annika; Neuhaus, Bernhard; Klopfleisch, Robert; Walker, Catherine; Buer, Jan; Müller, Werner; Epple, Matthias; Westendorf, Astrid M

    2016-01-28

    Cytokines and chemokines are predominant players in the progression of inflammatory bowel diseases. While systemic neutralization of these players with antibodies works well in some patients, serious contraindications and side effects have been reported. Therefore, the local interference of cytokine signaling mediated by siRNA-loaded nanoparticles might be a promising new therapeutic approach. In this study, we produced multi-shell nanoparticles consisting of a calcium phosphate (CaP) core coated with siRNA directed against pro-inflammatory mediators, encapsulated into poly(d,l-lactide-co-glycolide acid) (PLGA), and coated with a final outer layer of polyethyleneimine (PEI), for the local therapeutic treatment of colonic inflammation. In cell culture, siRNA-loaded CaP/PLGA nanoparticles exhibited a rapid cellular uptake, almost no toxicity, and an excellent in vitro gene silencing efficiency. Importantly, intrarectal application of these nanoparticles loaded with siRNA directed against TNF-α, KC or IP-10 to mice suffering from dextran sulfate sodium (DSS)-induced colonic inflammation led to a significant decrease of the target genes in colonic biopsies and mesenteric lymph nodes which was accompanied with a distinct amelioration of intestinal inflammation. Thus, this study provides evidence that the specific and local modulation of the inflammatory response by CaP/PLGA nanoparticle-mediated siRNA delivery could be a promising approach for the treatment of intestinal inflammation.

  20. Eggshell membrane powder ameliorates intestinal inflammation by facilitating the restitution of epithelial injury and alleviating microbial dysbiosis.

    Science.gov (United States)

    Jia, Huijuan; Hanate, Manaka; Aw, Wanping; Itoh, Hideomi; Saito, Kenji; Kobayashi, Shoko; Hachimura, Satoshi; Fukuda, Shinji; Tomita, Masaru; Hasebe, Yukio; Kato, Hisanori

    2017-03-08

    Gut microbiota is an essential factor in the shaping of intestinal immune system development and driving inflammation in inflammatory bowel disease (IBD). We report the effects and microbe-host interactions underlying an intervention using fine powder of eggshell membrane (ESM) against IBD. ESM attenuated lipopolysaccharide-induced inflammatory cytokine production and promoted the Caco-2 cell proliferation by up-regulating growth factors in vitro. In a murine model of dextran sodium sulphate-induced colitis, ESM significantly suppressed the disease activity index and colon shortening. These effects were associated with significant ameliorations of gene expressions of inflammatory mediators, intestinal epithelial cell proliferation, restitution-related factors and antimicrobial peptides. Multifaceted integrated omics analyses revealed improved levels of energy metabolism-related genes, proteins and metabolites. Concomitantly, cecal metagenomic information established an essential role of ESM in improving dysbiosis characterized by increasing the diversity of bacteria and decreasing absolute numbers of pathogenic bacteria such as Enterobacteriaceae and E. coli, as well as in the regulation of the expansion of Th17 cells by suppressing the overgrowth of segmented filamentous bacteria. Such modulations have functional effects on the host; i.e., repairing the epithelium, regulating energy requirements and eventually alleviating mucosal inflammation. These findings are first insights into ESM's modulation of microbiota and IBD suppression, providing new perspectives on the prevention/treatment of IBD.

  1. In vivo cleavage rate of a dextran-bound magnetic resonance imaging contrast agent: preparation and intravascular pharmacokinetic characteristics in the rabbit.

    Science.gov (United States)

    Hals, Petter Arnt; Sontum, Per Christian; Holtz, Eckart; Klaveness, Jo; Rongved, Pål

    2013-02-01

    Earlier described dextran-based contrast agents for magnetic resonance imaging (MRI) comprising the gadolinium chelate diethylenetriamine pentaacetic acid (GdDTPA, 1) have shown significantly shorter in vivo contrast duration in rat than what would be expected from the initial average molecular weight (Mw) of the dextran fraction (71.4 kD). To investigate this further, four dextran fractions with given initial average molecular weight (Mw) of 10.4, 41.0, 71.4 and 580 kD were used as starting material to prepare products 2-5 where one of the carboxylic acid functionalities in GdDTPA was used as a direct covalent ester linker to hydroxyl groups in dextrans. A fifth derivative (6) was an amide-ester bound β-alanine-DTPAGd conjugate with dextran having Mw 71.4 kD. The reference compound GdDTPA (1) and gadoliniumlabelled dextran derivatives 2-6 were injected intravenously in rabbits. Pharmacokinetic parameters showed that when GdDTPA is ester-bound directly to dextran hydroxyls, the cleavage rates of 2-5 were only moderately dependent on the molecular weights of the dextrans, having blood pool half-lives comparable to the low-molecular reference compound (t 1/2,β 0.3 - 0.5 hrs.). Presence of a β-alanine spacer in 6 prolonged the plasma half-life t 1/2,β to 6.9 hours, rendering a blood residence time suitable for blood pool slow release of GdDTPA. Biological cleavage regenerates the clinically acceptable carrier dextran and the β-alanine derivative of GdDTPA, pointing at a clinically acceptable product class for blood-pool contrast in MRI.

  2. Survey the effects of dietary sodium nitrite on the histological changes of the aortic artery in the adult male rats

    Directory of Open Access Journals (Sweden)

    Saeaid Khatamsaz

    2016-05-01

    Full Text Available Background: Because of high consumption of nitrite in processed (fast foods and high level of nitrite in water, soil and ecosystem, nitrite can endanger humans health. In this study the effects of sodium nitrite on aorta was examined in adult male rats. Materials and Methods : In the present study, 30 Wistar adult male rats were randomly divided into three groups of 10, including; control group. First experimental group that received low dose of sodium nitrite (175 mg/kg.bw, second experimental group that received high dose of sodium nitrite (350 mg/kg.bw. They were examined for 60 days. The rats got sodium nitrite through drinking water. At the end of the experiment the rats were taken to the anesthesia jar and based on ether principles, they anesthetized with ether and their blood samples were collected from their hearts. Then their aorta were extracted from their bodies and the tissue sections were prepared for testing tissue changes. Features such as histological features of aorta (morphometric and morphologic features were analyzed. The samples were stained with masson trichrome and Hematoxylin- Eosin methods. The internal media layer was measured with Image tool software. Then the amount of nitrite oxide in their blood were tested. At the end results were analyzed by 17 version of SPSS software and ANOVA test was run. Results: The results of this study showed that thickness of medial layer in two experimental group that received low and high dose of sodium nitrite compared with the control group decreased (p 0.05, and the group that received of high dose of sodium nitrite showed irregular and non- uniform state in aortic media layer. Conclusion: The finding of this study indicated that consumption of sodium nitrite in long term can induce damage in artries tissue.

  3. INCREASED CONCENTRATION OF NITRITE IN SYNOVIAL FLUID AND SERUM SAMPLES IN STEROID INDUCED FEMORAL HEAD NECROSIS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    To investigate the role of nitric oxide (NO) in steroid-induced femoral head necrosis, NO production was measured indirectly as nitrite in serum and synovial fluid samples from patients with steroid-induced femoral head necrosis together with serum samples from healthy volunteers matched for age and sex. The results showed that:① serum nitrite concentration in patients with femoral head necrosis were significantly lower than that in controls (P<0.001); ② nitrite level of synovial fluid was markedly higher than that of serum. In addition, there was a positive correlation between them (r=0.378,P<0.05). We reach the conclusion:① NO is synthesized by synovium and chondrocytes; ② the decreased NO concentration in serum suggests a protective role in steroid-induced femoral head necrosis.

  4. Evaluation of leukocyte esterase and nitrite strip tests to detect spontaneous bacterial peritonitis in cirrhotic patients

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the diagnostic efficacy of leukocyte esterase and nitrite reagent strips for bedside diagnosis of spontaneous bacterial peritonitis (SBP).METHODS: A total of 63 consecutive patients with cirrhotic ascites (38 male, 25 female) tested between April 2005 and July 2006 were included in the study. Bedside reagent strip testing was performed on ascitic fluid and the results compared to manual cell counting and ascitic fluid culture. SBP was defined as having a olymorphonuclear ascites count of ≥ 250/mm3.RESULTS: Fifteen samples showed SBP. The sensitivity,specificity, positive and negative predictive values of the leukocyte esterase reagent strips were; 93%, 100%, 100%, and 98%, respectively. The sensitivity,specificity, positive and negative predictive value of the nitrite reagent strips were 13%, 93%, 40%, and 77%, respectively. The combination of leukocyte esterase and nitrite reagents strips did not yield statistically significant effects on diagnostic accuracy. CONCLUSION: Leukocyte esterase reagent strips may provide a rapid, bedside diagnostic test for SBP.

  5. Directed Molecular Evolution of Nitrite Oxido-reductase by DNA-shuffling

    Institute of Scientific and Technical Information of China (English)

    JUN-WEN LI; JIN-LAI ZHENG; XIN-WEI WANG; MIN JIN; FU-HUAN CHAO

    2007-01-01

    Objective To develtop directly molecular evolution of nitrite oxido-reductase using DNA-shuffling technique because nitrobacteria grow extremely slow and are unable to nitrify effectively inorganic nitrogen in wastewater treatment. Methods The norB gene coding the nitrite oxido-reductase in nitrobacteria was cloned and sequenced. Then, directed molecular evolution of nitrite oxido-reductase was developed by DNA-shuffling of 15 norB genes from different nitrobacteria. Results After DNA-shuffling with sexual PCR and staggered extension process PCR, the sequence was different from its parental DNA fragments and the homology ranged from 98% to 99%. The maximum nitrification rate of the modified bacterium of X16 by modified bacterium had the same characteristics of its parental bacteria of E. coli and could grow rapidly in normal cultures.Conclusion DNA-shuffling was successfully used to engineer E. coli, which had norB gene and could degrade inorganic nitrogen effectively.

  6. Hemodynamic responses and serum nitrite concentration during uncontrolled hemorrhagic shock in normotensive and hypertensive rats.

    Science.gov (United States)

    Khazaei, Majid; Barmaki, Babak; Nasimi, Ali

    2012-09-01

    We evaluated the effect of hypertension on hemodynamic responses and serum nitrite concentrations in normotensive (NT) and deoxycorticosteron acetate (DOCA)-Salt hypertensive (HT) rats. Uncontrolled hemorrhagic shock was induced in NT and HT rats (n=7 each) by preliminary bleed of 25 ml/kg followed by a 75% tail amputation. The mean arterial pressure (MAP), heart rate and serum nitrite were measured pre-hemorrhage and during hemorrhage. Changes in time-averaged MAP after hemorrhage were significantly greater in HT group than NT. After resuscitation, the HT rats failed to restore MAP to baseline level. Serum nitrite level in both groups was significantly increased during shock period. Survival rate of HT animals was lower than NT group, although it was not statistically significant. Marked reduction of MAP and less improvement after resuscitation suggested the less adaptation of cardiovascular system in HT animals which may interfere with management of these subjects during uncontrolled hemorrhagic shock.

  7. Intramolecular electron transfer in cytochrome cd(1) nitrite reductase from Pseudomonas stutzeri; kinetics and thermodynamics

    DEFF Research Database (Denmark)

    Farver, Ole; Kroneck, Peter M H; Zumft, Walter G

    2002-01-01

    , internal electron transfer between these sites is an inherent element in the catalytic cycle of this enzyme. We have investigated the internal electron transfer reaction employing pulse radiolytically produced N-methyl nicotinamide radicals as reductant which reacts solely with the heme-c in an essentially...... diffusion controlled process. Following this initial step, the reduction equivalent is equilibrating between the c and d(1) heme sites in a unimolecular process (k=23 s(-1), 298 K, pH 7.0) and an equilibrium constant of 1.0. The temperature dependence of this internal electron transfer process has been......Cytochrome cd(1) nitrite reductase from Pseudomonas stutzeri catalyzes the one electron reduction of nitrite to nitric oxide. It is a homodimer, each monomer containing one heme-c and one heme-d(1), the former being the electron uptake site while the latter is the nitrite reduction site. Hence...

  8. Role of nitrite in regulation of fetal cephalic circulation in sheep.

    Science.gov (United States)

    Truong, Giang T; Schröder, Hobe J; Liu, Taiming; Zhang, Meijuan; Kanda, Eriko; Bragg, Shannon; Power, Gordon G; Blood, Arlin B

    2014-04-15

    Nitrite has been postulated to provide a reservoir for conversion to nitric oxide (NO), especially in tissues with reduced oxygen levels as in the fetus. Nitrite would thus provide local vasodilatation and restore a balance between oxygen supply and need, a putative mechanism of importance especially in the brain. The current experiments test the hypothesis that exogenous nitrite acts as a vasodilator in the cephalic vasculature of the intact, near term fetal sheep. Fetuses were first instrumented to measure arterial blood pressure and carotid artery blood flow and then studied 4-5 days later while in utero without anaesthesia. Initially l-nitro-arginine (LNNA) was given to block endogenous NO production. Carotid resistance to flow increased 2-fold from 0.54 ± 0.01 (SEM) to 1.20 ± 0.08 mmHg min ml(-1) (in 13 fetuses, P fetal sheep.

  9. Effect of wall growth on the kinetic modeling of nitrite oxidation in a CSTR.

    Science.gov (United States)

    Dokianakis, Spiros N; Kornaros, Michael; Lyberatos, Gerasimos

    2006-03-05

    A simple kinetic model was developed for describing nitrite oxidation by autotrophic aerobic nitrifiers in a continuous stirred tank reactor (CSTR), in which mixed (suspended and attached) growth conditions prevail. The CSTR system was operated under conditions of constant nitrite feed concentration and varying volumetric flow rates. Experimental data from steady-state conditions in the CSTR system and from batch experiments were used for the determination of the model's kinetic parameters. Model predictions were verified against experimental data obtained under transient operating conditions, when volumetric flow rate and nitrite feed concentration disturbances were imposed on the CSTR. The presented kinetic modeling procedure is quite simple and general and therefore can also be applied to other mixed growth biological systems.

  10. Photoperiodic stress on nitrite production by splenic macrophages in fresh-water snake Natrix piscator

    Directory of Open Access Journals (Sweden)

    Tripathi Manish Kumar

    2012-05-01

    Full Text Available Changes in day length enhance or suppress component of immune function in individuals of several species. The purpose of the present experiment was to study the role of photoperiodic manipulation on the nitric oxide production by splenic macrophages in the fresh-water snake, Natrix piscator. To study effect of photoperiod, animals were subjected to 24 hour continuous light and continuous dark for 30 days. Animals kept in natural day length served as control. At termination of experiments, animals were sacrificed, and spleen was excised. Macrophages were incubated for 24 hours and nitric oxide production was measured by measuring the nitrite concentration. Nitrite production was significantly decreased to the cultures obtained from the animals kept under continuous light. No change in nitrite concentration was found in animals kept under continuous dark, when compared to the animals kept under natural day length. The possible role of decreased melatonin synthesis in light is suggested to decrease the nitric oxide production.

  11. p-CMB-dextran T 10. A useful tool in evaluating the functional importance of superficial SH-groups in rat adipocytes.

    Science.gov (United States)

    Simon, B; Kather, H

    1975-05-01

    A large SH-blocking reagent p-CMB-dextran T 10 (MW about 10,000) was applied to isolated rat adipocytes. This compound possesses the same reactivity towards SH-groups as uncoupled p-CMB. P-CMB-Dextran T 10 did not influence the basal glucose uptake in contrast to uncoupled p-CMB. The results are discussed with respect to the usefulness of p-CMB-dextran T 10 in evaluating the role of superficial SH-groups in various membrane functions.

  12. [Presence of nitrates and nitrites in baker's products and in certain other flour products].

    Science.gov (United States)

    Nabrzyski, M; Gajewska, R; Ganowiak, Z

    1990-01-01

    The results of the study demonstrated that the content of nitrates and nitrites in various baker's products varied from 0.96 (in wheat rolls and baguettes) to 44.07 mg KO3/kg in pumpernickel bread. In wholemeal bread, village bread, tourist bread, rye brown bread and Graham bread the content of these compounds was from 1.46 to 27.10 mg KNO3/kg. The mean content of nitrites in these bread sorts was 1.76 mg NaNo2/kg, range 0.10-4.40 mg NaNo2/kg. In white wheat flours (Wrocław flour, cake flour and Poznań flour) the content of nitrates ranged from 1.10 to 19.08 mg KNO3/kg, and in the dishes produced from them in household was from 0.50 to 16.33 mg KNO3/kg. The content of nitrites in these flours was in the range from 0.00 to 4.16 mg NaNo2/kg, and in the products prepared from them it was from 0.00 to 1.60 mg NaNO2/kg. Eleven types were tested also of popular biscuits, wafers, gingerbread and hard cakes in which the content of nitrates was from 3.66 to 17.72 mg/kg, and that of nitrites was from 0.00 to 8.80 mg NaNo2/kg. Considering the average consumption of these products per one person in the seashore region and the mean values of nitrates and nitrites it was calculated that they provided daily about 3.9 mg KNO3 and 0.4 NaNo2, that is about 1.8% of nitrates and 7.7% of nitrites consumed by adults in daily food ration.

  13. Researches concerning nitrates and nitrites accumulation in carrots, along of the vegetation stages

    Directory of Open Access Journals (Sweden)

    Monica NEGREA

    2008-05-01

    Full Text Available The presented paper deals with the determination of nitrates and nitrites content in carrots, in different vegetation stages of the carrot culture. High nitrates and nitrites concentration in vegetables is mainly due to excessive nitrogen content in the soil system, thus deteriorating the nutritional and hygienic values of products and complicating the processing and storage. The determination was tested on carrot samples assayed from an experimental field set up near Timisoara. In experimental field, to the carrot culture was administrated different doses of fertilizers (NPK and the samples for analysis were assayed in different phases of vegetation. The obtained results indicated that the highest level of nitrate in carrots was found to the variant b3 (N150P90K90 in experimental field, who was above maximum limit allowed (LMA. Maximum limit allowed for nitrates in carrots, in accordance with ORDER No. 293/640/2001-1/2002 regarding security and quality conditions for vegetables and fresh fruits for human consumption is 400 ppm. For all other samples of carrots the nitrates level was below of LMA. The nitrite content grows in case of fertilizer administration during the whole vegetation stages of the plant. In variant N150P90K90 the nitrite content was above (LMA in carrot samples in all stages of vegetation. The nitrite content in carrots should not exceed 1-2 ppm. Nitrate and nitrite content in carrots was done with the help of High Performance Liquid Chromatography (HPLC in the Laboratory for the Measurement of Residues of the Department of Agro-techniques of the U.S.A-V.M.B in Timisoara.

  14. Investigation of the photocatalytic effect of zinc oxide nanoparticles in the presence of nitrite

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Min; Abbood, Hayder A. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China); Zhu, Zhening [National Center for Nanoscience and Technology, No.11 ZhongGuanCun BeiYiTiao Road, Beijing 100190 (China); Li, Hailing [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China); Gao, Zhonghong, E-mail: zhgao144@mail.hust.edu.cn [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China)

    2013-01-15

    Highlights: ► Nitrite enhanced the photo-damage by ZnO nanoparticles to BSA and HaCaT cells. ► Protein nitration was induced by nitrite in photo-damaged BSA and HaCaT cells. ► The effects of photo-damage on BSA were affected by various factors. ► 50-nm ZnO induced more apoptosis than 90-nm ZnO in HaCaT cells. -- Abstract: Zinc oxide nanoparticles are widely used in sunscreen products because of their chemical stability and capability of blocking harmful ultraviolet rays. However, zinc oxide nanoparticles can also generate reactive species under ultraviolet irradiation. Because nitrite can form reactive nitrogen species under oxidative stress and because it exists in perspiration and cosmetics, we studied the effects of nitrites on the photocatalytic damage of zinc oxide nanoparticles (50 nm and 90 nm) to bovine serum albumin and human keratinocyte cells under ultraviolet irradiation (365 nm and 254 nm). The results indicate that nitrite plays an enhancing role in photocatalytic damage by breaking amino acid residues and promoting protein oxidation and nitration. The concentrations of zinc oxide and nitrite, the irradiation light and duration, and the pH of the medium are important factors influencing this photocatalytic damage. Size effects of ZnO nanoparticles on bovine serum albumin and keratinocyte cells are different. It is speculated that the extent of photo-damage is partially dependent on the aggregation of zinc oxide. These findings may be valuable for understanding potential risks of applying zinc oxide nanoparticle-containing sunscreens to human skin under sunlight exposure.

  15. Electrochemical Determination of Food Preservative Nitrite with Gold Nanoparticles/p-Aminothiophenol-Modified Gold Electrode

    Directory of Open Access Journals (Sweden)

    Ayşem Üzer

    2016-08-01

    Full Text Available Due to the negative impact of nitrate and nitrite on human health, their presence exceeding acceptable levels is not desired in foodstuffs. Thus, nitrite determination at low concentrations is a major challenge in electroanalytical chemistry, which can be achieved by fast, cheap, and safe electrochemical sensors. In this work, the working electrode (Au was functionalized with p-aminothiophenol (p-ATP and modified with gold nanoparticles (Au-NPs to manufacture the final (Au/p-ATP-Aunano electrode in a two-step procedure. In the first step, p-ATP was electropolymerized on the electrode surface to obtain a polyaminothiophenol (PATP coating. In the second step, Au/p-ATP-Aunano working electrode was prepared by coating the surface with the use of HAuCl4 solution and cyclic voltammetry. Determination of aqueous nitrite samples was performed with the proposed electrode (Au/p-ATP-Aunano using square wave voltammetry (SWV in pH 4 buffer medium. Characteristic peak potential of nitrite samples was 0.76 V, and linear calibration curves of current intensity versus concentration was linear in the range of 0.5–50 mg·L−1 nitrite with a limit of detection (LOD of 0.12 mg·L−1. Alternatively, nitrite in sausage samples could be colorimetrically determined with high sensitivity by means of p-ATP‒modified gold nanoparticles (AuNPs and naphthylethylene diamine as coupling agents for azo-dye formation due to enhanced charge-transfer interactions with the AuNPs surface. The slopes of the calibration lines in pure NO2− solution and in sausage sample solution, to which different concentrations of NO2− standards were added, were not significantly different from each other, confirming the robustness and interference tolerance of the method. The proposed voltammetric sensing method was validated against the colorimetric nanosensing method in sausage samples.

  16. Electrochemical Determination of Food Preservative Nitrite with Gold Nanoparticles/p-Aminothiophenol-Modified Gold Electrode.

    Science.gov (United States)

    Üzer, Ayşem; Sağlam, Şener; Can, Ziya; Erçağ, Erol; Apak, Reşat

    2016-08-02

    Due to the negative impact of nitrate and nitrite on human health, their presence exceeding acceptable levels is not desired in foodstuffs. Thus, nitrite determination at low concentrations is a major challenge in electroanalytical chemistry, which can be achieved by fast, cheap, and safe electrochemical sensors. In this work, the working electrode (Au) was functionalized with p-aminothiophenol (p-ATP) and modified with gold nanoparticles (Au-NPs) to manufacture the final (Au/p-ATP-Aunano) electrode in a two-step procedure. In the first step, p-ATP was electropolymerized on the electrode surface to obtain a polyaminothiophenol (PATP) coating. In the second step, Au/p-ATP-Aunano working electrode was prepared by coating the surface with the use of HAuCl₄ solution and cyclic voltammetry. Determination of aqueous nitrite samples was performed with the proposed electrode (Au/p-ATP-Aunano) using square wave voltammetry (SWV) in pH 4 buffer medium. Characteristic peak potential of nitrite samples was 0.76 V, and linear calibration curves of current intensity versus concentration was linear in the range of 0.5-50 mg·L(-1) nitrite with a limit of detection (LOD) of 0.12 mg·L(-1). Alternatively, nitrite in sausage samples could be colorimetrically determined with high sensitivity by means of p-ATP‒modified gold nanoparticles (AuNPs) and naphthylethylene diamine as coupling agents for azo-dye formation due to enhanced charge-transfer interactions with the AuNPs surface. The slopes of the calibration lines in pure NO₂(-) solution and in sausage sample solution, to which different concentrations of NO₂(-) standards were added, were not significantly different from each other, confirming the robustness and interference tolerance of the method. The proposed voltammetric sensing method was validated against the colorimetric nanosensing method in sausage samples.

  17. Electrochemical Determination of Food Preservative Nitrite with Gold Nanoparticles/p-Aminothiophenol-Modified Gold Electrode

    Science.gov (United States)

    Üzer, Ayşem; Sağlam, Şener; Can, Ziya; Erçağ, Erol; Apak, Reşat

    2016-01-01

    Due to the negative impact of nitrate and nitrite on human health, their presence exceeding acceptable levels is not desired in foodstuffs. Thus, nitrite determination at low concentrations is a major challenge in electroanalytical chemistry, which can be achieved by fast, cheap, and safe electrochemical sensors. In this work, the working electrode (Au) was functionalized with p-aminothiophenol (p-ATP) and modified with gold nanoparticles (Au-NPs) to manufacture the final (Au/p-ATP-Aunano) electrode in a two-step procedure. In the first step, p-ATP was electropolymerized on the electrode surface to obtain a polyaminothiophenol (PATP) coating. In the second step, Au/p-ATP-Aunano working electrode was prepared by coating the surface with the use of HAuCl4 solution and cyclic voltammetry. Determination of aqueous nitrite samples was performed with the proposed electrode (Au/p-ATP-Aunano) using square wave voltammetry (SWV) in pH 4 buffer medium. Characteristic peak potential of nitrite samples was 0.76 V, and linear calibration curves of current intensity versus concentration was linear in the range of 0.5–50 mg·L−1 nitrite with a limit of detection (LOD) of 0.12 mg·L−1. Alternatively, nitrite in sausage samples could be colorimetrically determined with high sensitivity by means of p-ATP‒modified gold nanoparticles (AuNPs) and naphthylethylene diamine as coupling agents for azo-dye formation due to enhanced charge-transfer interactions with the AuNPs surface. The slopes of the calibration lines in pure NO2− solution and in sausage sample solution, to which different concentrations of NO2− standards were added, were not significantly different from each other, confirming the robustness and interference tolerance of the method. The proposed voltammetric sensing method was validated against the colorimetric nanosensing method in sausage samples. PMID:27490543

  18. Investigation of Ammonium and Nitrite Removal by Zeolite Material Synthesized on Red Mud Base

    Directory of Open Access Journals (Sweden)

    Pham Thi Mai Huong

    2017-07-01

    Full Text Available The zeolite with the unit formula of Na8(Al6Si6O24S.4H2O was synthesized directly on red mud base with addition of single silicon (signed as RH-ZeO-Si and both silicon and aluminum portions (signed as RM-ZeO-SiAl to original Tan Rai (Vietnam red mud. The structure of the zeolite was studied by X-Ray difration and FT-IR absorption spectra. The synthesized materials were studied on their adsorption ability of ammonium and nitrite ions. The results showed that, the adsorption of ammonium cation was mostly allowing ion-exchange mechanism and the zeolite crystaline forms played predominantly role besids minor one of single metal oxides. For nitrite anions, it is otherwise, the adsorption mechanism was mostly leant to electrostatic attraction between nitrite anions and electropositive effect of the hematite surface in light acidic condition. The adsorption isotherms of all ammonium and nitrite ions on both synthesized materials were nearly conformable with Freundlich model than Langmuir model. Those showed that, both materials have unhomogeneous adsorption surface. The maximum adsorption capacity of ammonium and nitrite on RM-ZeO-Si was 5.71 mg/g and 2.73 mg/g respectively, and on RM-ZeO-SiAl was 5.61 mg/g and 3.12 mg/g respectively. The initial test of competitive ions influencing on adsorption ability showed that, for all cases the competition of cations to ammonium ion was more significance than those of anions to nitrite ion in the same conditions.

  19. On the optimum conditions for the reduction of nitrate to nitrite by cadmium.

    Science.gov (United States)

    Nydahl, F

    1976-05-01

    The variables of direct importance in the reduction of nitrate to nitrite by a metallic reductant such as cadmium used in a reductor column are discussed with special reference to the determination of nitrate as nitrite in very dilute solutions, e.g., natural waters. As a result of these considerations the effect of flow-rate (expressed as bed-volumes min ), pH, temperature, chloride concentration and various types of reductor cadmium on the yield of nitrite is investigated. The effect of dissolved oxygen in the sample solution on pH and cadmium concentration in the reduced solution is demonstrated. At constant pH a maximum yield of nitrite is obtained at a certain flow-rate, which is explained as the result of a rapid formation and simultaneously proceeding slow reduction of nitrite. With increasing pH this maximum is shifted to lower flow-rates, and grows broader whilst the yield at maximum approaches 100%; at pH 9.5 a yield of 99.9 +/- 0.1% is obtained. The temperature has little effect on the reduction rate in the interval 20-30 degrees but at 10 degrees the reduction is noticeably slower. Chloride ions have a strongly retarding effect on the reduction rate but the yield at maximum is not affected. Electrolytically precipitated cadmium, filings of pure cadmium or amalgamated pure cadmium all give practically the same yield at maximum though some differences in reduction rate are observed. Impure cadmium or copper-cadmium and silver-cadmium, owing to the formation of galvanic cells with higher reducing power, give a high reduction rate, which also applies to nitrite, causing a poorer yield at maximum. The practical consequences of the results are thoroughly discussed.

  20. Co-treatment with conjugated linoleic acid and nitrite protects against myocardial infarction

    Directory of Open Access Journals (Sweden)

    Natia Qipshidze-Kelm

    2014-01-01

    Full Text Available According to the CDC, the most common type of heart disease is coronary artery disease, which commonly leads to myocardial infarction (MI. Therapeutic approaches to lessen the resulting cardiovascular injury associated with MI are limited. Recently, MicroRNAs (miRNAs have been shown to act as negative regulators of gene expression by inhibiting mRNA translation and/or stimulating mRNA degradation. A single miRNA can modulate physiological or disease phenotypes by regulating whole functional systems. Importantly, miRNAs can regulate cardiac function, thereby modulating heart muscle contraction, heart growth and morphogenesis. MicroRNA-499 (miRNA-499 is a cardiac-specific miRNA that when elevated causes cardiomyocyte hypertrophy, in turn preventing cardiac dysfunction during MI. Previous studies revealed that combination treatment with conjugated linoleic acid (cLA and nitrite preserved cardiovascular function in mice. Therefore, it was hypothesized that cLA and nitrite may regulate miRNA-499, thus providing cardiac protection during MI. To test this hypothesis, 12-week old mice were treated with cLA (10 mg/kg/d-via osmotic mini-pump or cLA and nitrite (50 ppm-drinking water 3 days prior to MI (ligation of the left anterior descending artery. Echocardiography and pressure–volume (PV-loop analysis revealed that cLA and nitrite-treated MI mice had improved heart function (10 days following MI compared to untreated MI mice. Treatment with cLA and nitrite significantly induced levels of miRNA-499 compared to untreated MI mice. In addition, treatment with cLA and nitrite abolished MI-induced protein expression of p53 and dynamin-related protein-1 (DRP-1. Moreover, the antioxidant enzyme expression of heme oxygenase-1 (HO-1 was elevated in MI mice treated with cLA and nitrite compared to untreated MI mice. Confocal imaging on heart tissue confirmed expression the levels of HO-1 and p53. Taken together, these results suggest that therapeutic

  1. Modeling pitting corrosion of iron exposed to alkaline solutions containing nitrate and nitrite

    Science.gov (United States)

    Chen, Lifeng

    2001-07-01

    Pitting corrosion could be extremely serious for dilute high-level radioactive waste stored or processed in carbon steel tanks at the Savannah River Site. In these solutions, nitrate is an aggressive ion with respect to pitting of carbon steel while nitrite can be used as an inhibitor. Excessive additions of nitrite increase the risk of generating unstable nitrogen compounds during waste processing, and insufficient additions of nitrite could increase the risk of corrosion-induced failure. Thus there are strong incentives to obtain a fundamental understanding of the role of nitrite in pitting corrosion prevention with these solution chemistries. In this dissertation, both a 1-D and a 2-D model are used to study the pitting mechanism as a function of nitrite/nitrate ratios. The 1-D model used BAND(J) to test a reaction mechanism for the passivation behavior by comparing the predicted Open Circuit Potential (OCP) with OCP data from experiments at different NO2-/NO3- ratio. The model predictions are compared with Cyclic Potentiodynamic Polarization (CPP) experiments. A 2-D model was developed for the propagation of a pit in iron by writing subroutines for finite element software of GAMBIT and FIDAP. Geometrically distributed anodic and cathodic reactions are assumed. The results show three partial explanations describing the inhibition influence of nitrite to iron corrosion: the competing reduction reaction of nitrate to nitrite, the formation of Fe(OH)+, and the function of the porous film. The current distributions and the effect of porosity of the film on pH are also explained. The calculation results also show that rate of pit growth decreases as the pit diameter increases until it reaches a constant value. The profile of the local current density on the pit wall is parabolic for small pits and it changes to a linear distribution for large pits. The model predicts that addition of nitrite will decrease the production of ferrous ions and those can prevent iron from

  2. Comparative Behaviour of Nitrite and Nitrate for the Protection of Rebar Corrosion

    Science.gov (United States)

    Ahmad, Altaf; Kumar, Anil

    2016-10-01

    Corrosion of rebar steel due to environmental causes has been studied through various approaches, and among the protection techniques use of inhibitors has gained encouragement. Nitrites and nitrates of sodium have gained sufficient scientific coverage. Recently, nitrites and nitrates of calcium have been verified in some studies, which, however, needs further experimentation through different angles. Simple polarization technique has been utilized in the present study to compare inhibitive efficiency of these salts of sodium and calcium, which indicate that calcium salts are more efficient.

  3. Nitrate and nitrite contents in Cuban cheese of the Gouda type.

    Science.gov (United States)

    García Rocaé, M O; del Pozo, E; Izquierdo, L; Fontaine, M

    1983-01-01

    The nitrate and nitrite contents in cheese of the Gouda type, produced by the Milk Complex of Havanna, were investigated and compared with those found in 5 types of imported cheese consumed in Cuba. No significant differences were found in the mean value (mean) of NaNO3, whereas in the mean value (mean) of NaNO2 differences were found when comparing all cheeses against each other. From these results it is inferred that the consumption of Gouda type cheese does not represent an important contribution to the daily intake of nitrates and nitrites, precursors in the synthesis of cancerogenic N-nitroso compounds.

  4. Enhancement of Nitrite Reduction Kinetics on Electrospun Pd-Carbon Nanomaterial Catalysts for Water Purification.

    Science.gov (United States)

    Ye, Tao; Durkin, David P; Hu, Maocong; Wang, Xianqin; Banek, Nathan A; Wagner, Michael J; Shuai, Danmeng

    2016-07-20

    We report a facile synthesis method for carbon nanofiber (CNF) supported Pd catalysts via one-pot electrospinning and their application for nitrite hydrogenation. A mixture of Pd acetylacetonate (Pd(acac)2), polyacrylonitrile (PAN), and nonfunctionalized multiwalled carbon nanotubes (MWCNTs) was electrospun and thermally treated to produce Pd/CNF-MWCNT catalysts. The addition of MWCNTs with a mass loading of 1.0-2.5 wt % (to PAN) significantly improved nitrite reduction activity compared to the catalyst without MWCNT addition. The results of CO chemisorption confirmed that the addition of MWCNTs increased Pd exposure on CNFs and hence improved catalytic activity.

  5. Reductive cleavage of nitrite to form terminal uranium mono-oxo complexes.

    Science.gov (United States)

    Lewis, Andrew J; Carroll, Patrick J; Schelter, Eric J

    2013-01-09

    Uranium terminal mono-oxo complexes are prepared with a unique activation of nitrite following reductive cleavage of an N-O bond with loss of nitric oxide. The thermodynamic driving force of U═O bond formation differentiates this reactivity from known mechanisms of nitrite reduction, which are typically mediated by proton transfer. Mechanistic details are explored by DFT supporting a simple homolytic cleavage pathway from a κ(1)-ONO bound intermediate. Complexes of the formula U(VI)OX[N(SiMe(3))(2)](3) are formed providing a trigonal bipyramidal framework into which ligands trans to the U═O bond may be installed.

  6. Iron-Doped Titania Nanoparticles for the Photocatalytic Oxidative Degradation of Nitrite

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0. 5 %. The increase in photoactivity is probably due to the higher adsorption and the inhibition of electron-hole recombination. The photocatalytic oxidation reaction of nitrite over the Fe-doped TiO2 catalyst follows zero-order kinetics, which is different from that over pure TiO2. The reaction rate decreases linearly with the increase of the pH of the solution.

  7. Evaluation of the nitrite and leukocyte esterase activity tests for the diagnosis of acute symptomatic urinary tract infection in men.

    NARCIS (Netherlands)

    Koeijers, J.J.; Kessels, A.G.H.; Nys, S.; Bartelds, A.; Donker, G.; Stobberingh, E.; Verbon, A.

    2007-01-01

    For 422 male patients with symptoms indicative of a urinary tract infection, nitrite and leukocyte esterase activity dipstick test results were compared with results of culture of urine samples. The positive predictive value of a positive nitrite test result was 96%. Addition of results of the leuko

  8. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    Science.gov (United States)

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO₂-N/L, aerobic P-uptake and oxidation of intercellular poly-β-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO₂-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite.

  9. Evaluation of the nitrite and leukocyte esterase activity tests for the diagnosis of acute symptomatic urinary tract infection in men.

    NARCIS (Netherlands)

    Koeijers, J.J.; Kessels, A.G.H.; Nys, S.; Bartelds, A.; Donker, G.; Stobberingh, E.; Verbon, A.

    2007-01-01

    For 422 male patients with symptoms indicative of a urinary tract infection, nitrite and leukocyte esterase activity dipstick test results were compared with results of culture of urine samples. The positive predictive value of a positive nitrite test result was 96%. Addition of results of the

  10. Aldehyde-Selective Wacker-Type Oxidation of Unbiased Alkenes Enabled by a Nitrite Co-Catalyst

    KAUST Repository

    Wickens, Zachary K.

    2013-09-13

    Breaking the rules: Reversal of the high Markovnikov selectivity of Wacker-type oxidations was accomplished using a nitrite co-catalyst. Unbiased aliphatic alkenes can be oxidized with high yield and aldehyde selectivity, and several functional groups are tolerated. 18O-labeling experiments indicate that the aldehydic O atom is derived from the nitrite salt.

  11. Detection of nitrate/nitrite bioavailability in wastewater using a luxCDABE-based Klebsiella oxytoca bioluminescent bioreporter.

    Science.gov (United States)

    Abd-El-Haleem, Desouky; Ripp, Steven; Zaki, Sahar; Sayler, Gary S

    2007-08-01

    In the present study, we have constructed a bioluminescent bioreporter for the assessment of nitrate/nitrite bioavailability in wastewater. Specifically, an approximately 500-bp DNA fragment containing a nitrate/nitrite-activated nasR-like promoter (regulating expression of genes encoding nitrite reductase in the genus Klebsiella) was fused upstream of the Vibrio fischeri luxCDABE gene cassette in a modified mini-Tn5 vector. Characterization of this strain, designated W6-1, yielded dose-dependent increased bioluminescence coincident with increased nitrate, nitrite, and ammonium added to the growth medium from 1 to 11 ppm. Bioluminescence in response to nitrogen species addition was light dependent up to 10, 7, and 8 ppm with nitrate, nitrite, and ammonium, respectively. This response was linear in the range from 1 to 8 ppm for nitrate (R2 = 0.98), 1 to 6 ppm for nitrite (R2 = 0.99), and 1 to 7 ppm for ammonium (R2 = 0.99). A significant bioluminescent response was also recorded when strain W6-1 was incubated with slurries from aged, nitrate/nitrite contaminated wastewater. Thus, bioreporter strain W6-1 can be used to elucidate factors that constrain the use of nitrate/nitrite in wastewaters.

  12. Dramatic increase of nitrite levels in hearts of anoxia-exposed crucian carp supporting a role in cardioprotection

    DEFF Research Database (Denmark)

    Sandvik, Guro K.; Nilsson, Göran E.; Jensen, Frank Bo

    2012-01-01

    Nitrite (NO2-) functions as an important nitric oxide (NO) donor under hypoxic conditions.Both nitrite and NO have been found to protect the mammalian heart and other tissues against ischemia(anoxia)-reoxygenation injury by interacting with mitochondrial electron transport complexes and limiting ...

  13. Photolysis of n-butyl nitrite and isoamyl nitrite at 355 nm: A time-resolved Fourier transform infrared emission spectroscopy and ab initio study

    CERN Document Server

    Ji, Min; Zhang, Qun; Chen, Yang

    2009-01-01

    We report on the photodissociation dynamics study of n-butyl nitrite (n-C_4H_9ONO) and isoamyl nitrite ((CH_3)_2C_3H_5ONO) by means of time-resolved Fourier transform infrared (TR-FTIR) emission spectroscopy. The obtained TR-FTIR emission spectra of the nascent NO fragments produced in the 355-nm laser photolysis of the two alkyl nitrite species showed an almost identical rotational temperature and vibrational distributions of NO. In addition, a close resemblance between the two species was also found in the measured temporal profiles of the IR emission of NO and the recorded UV absorption spectra. The experimental results are consistent with our ab initio calculations using the time-dependent density functional theory at the B3LYP/6-311G(d,p) level, which indicate that the substitution of one of the two {gamma}-H atoms in n-C_4H_9ONO with a methyl group to form (CH_3)_2C_3H_5ONO has only a minor effect on the photodissociation dynamics of the two molecules.

  14. Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Tsai, S C; ElSohly, M A; Dubrovsky, T; Twarowska, B; Towt, J; Salamone, S J

    1998-10-01

    The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even

  15. De novo biofilm community assembly from tap water source communities favors Nitrotoga over Nitrospira under elevated nitrite surface loading

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen;

    -through biofilm system to continuous immigration from a tap water metacommunity while applying different nitrite surface loading rates. After 63 days of operation, we extracted biofilms and analyzed the community composition via Illumina MiSeq targeting the 16S rRNA gene. Previous studies have shown......Four main processes are considered to drive microbial community assembly: selection, drift, dispersal and speciation. These processes occur simultaneously, but the extent to which each process contributes to community assembly is unclear in natural communities. We exposed a high-throughput flow...... that Nitrospira is the dominant nitrite oxidizing genus in low nitrite environments. Hence, we postulated that by elevating the nitrite surface loading we would select for NOB with lower nitrite affinity than Nitrospira. We observed different dominant NOB species under different loading rates. While...

  16. Comparison of endogenous metabolism during long-term anaerobic starvation of nitrite/nitrate cultivated denitrifying phosphorus removal sludges.

    Science.gov (United States)

    Wang, Yayi; Zhou, Shuai; Wang, Hong; Ye, Liu; Qin, Jian; Lin, Ximao

    2015-01-01

    Denitrifying phosphorus removal (DPR) by denitrifying phosphorus-accumulating organisms (DPAOs) is a promising approach for reducing energy and carbon usage. However, influent fluctuations or interruptions frequently expose the DPAOs biomass to starvation conditions, reducing biomass activity and amount, and ultimately degrading the performance of DPR. Therefore, a better understanding of the endogenous metabolism and recovery ability of DPAOs is urgently required. In the present study, anaerobic starvation (12 days) and recovery were investigated in nitrite- and nitrate-cultivated DPAOs at 20 ± 1 °C. The cell decay rates in nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were 0.008 day⁻¹ and 0.007 day⁻¹, respectively, being 64% and 68% lower than those of nitrate-DPAOs sludges. Nitrite-DPAOs sludges also recovered more rapidly than nitrate-DPAOs sludge after 12 days of starvation. The maintenance energy of nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were approximately 31% and 34% lower, respectively, than those of nitrate-DPAOs sludges. Glycogen and polyphosphate (poly-P) sequentially served as the main maintenance energy sources in both nitrite-and nitrate-DPAOs sludges. However, the transformation pathway of the intracellular polymers during starvation differed between them. Nitrate-DPAOs sludge used extracellular polymeric substances (EPS) (mainly polysaccharides) as an additional maintenance energy source during the first 3 days of starvation. During this phase, EPS appeared to contribute to 19-27% of the ATP production in nitrate-DPAOs, but considerably less to the cell maintenance of nitrite-DPAOs. The high resistance of nitrite-DPAOs to starvation might be attributable to frequent short-term starvation and exposure to toxic substances such as nitrite/free nitrous acids in the parent nitrite-fed reactor. The strong resistance of nitrite-DPAOs sludge to anaerobic starvation may be exploited in P removal

  17. Achieving the nitrite pathway using FA inhibition and process control in UASB-SBR system removing nitrogen from landfill leachate

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An up-flow sludge blanket(UASB) and sequencing batch reactor(SBR) system was introduced to remove organics and nitrogen from landfill leachate.The synergetic effect of free ammonia(FA) inhibition and process control was used to achieve the nitrite pathway in the SBR.In previous research,inhibition of FA on nitrite oxidizing bacteria(NOB) activity has been revealed and the process control parameters(DO,ORP and pH) exactly indicate the end-point of nitritation.The method was implemented in the SBR achieving stable nitrogen removal via the nitrite pathway from landfill leachate.The degree of nitrite accumulation during the nitritation was monitored along with the simultaneous and advanced removal of organics and nitrogen in the UASB-SBR system.The nitrifying bacteria community was quantitatively analyzed by fluorescence in situ hybridization(FISH) techniques.Batch tests were carried out to investigate the denitritation kinetics of microbial bacteria in the SBR.Experimental results showed that the nitrite pathway could be repeatedly and reliably achieved by synergetic effect of FA inhibition and process control.FISH analysis showed the dominant nitrifying bacteria were ammonia-oxidizing β-Proteobacteria. Relationship between nitrite concentration and nitrite reduction rate followed the Monod-type equation.The maximum specific nitrite utilization rate(k) and half-velocity constant(Ks) were calculated as 0.44 gN gVSS-1d-1and 15.8 mg L-1,respectively.

  18. Comparison effects of dietary iron dextran and bacterial-iron supplementation on growth performance, fecal microbial flora, and blood profiles in sows and their litters.

    Science.gov (United States)

    Zhao, Pinyao; Upadhaya, Santi Devi; Li, Jian; Kim, Inho

    2015-11-01

    This study was conducted to compare effects of dietary administration of iron dextran and bacterial-iron on growth performance, fecal microbial flora, and blood profiles in sows and their litters. A total of 20 multiparous sows (Landrace × Yorkshire) were randomly allotted into two treatments: (i) ID (basal diet, piglets were injected with iron dextran); (ii) BR (basal diet + bacterial-iron; bacterial-iron was given to sows, piglets were not injected with iron dextran). There were five replicates per treatment with two sows per replicate. No differences were observed on sow and piglet growth performance, fecal microbial flora as well as sow blood profiles between ID and BR treatments. In piglets, blood iron, red blood cell and hemoglobin concentrations in ID treatment were higher (P growth performance in lactating sows and piglets, but iron dextran injection has higher blood iron, white blood cell, red blood cell and hemoglobin concentrations in piglets.

  19. Amelioration of cisplatin-induced nephrotoxicity by statins

    Directory of Open Access Journals (Sweden)

    Rajesh A Maheshwari

    2013-01-01

    Conclusions: This finding suggests that simvastatin and rosuvastatin may have a protective effect against cisplatin-induced kidney damage via amelioration of lipid peroxidation as well as due to improvement of renal function, and lipid-lowering effects.

  20. Intraventricular infusion of hyperosmolar dextran induces hydrocephalus: a novel animal model of hydrocephalus

    Directory of Open Access Journals (Sweden)

    Krishnamurthy Satish

    2009-12-01

    Full Text Available Abstract Background Popular circulation theory of hydrocephalus assumes that the brain is impermeable to cerebrospinal fluid (CSF, and is therefore incapable of absorbing the CSF accumulating within the ventricles. However, the brain parenchyma is permeable to water due to the presence of specific ion channels as well as aquaporin channels. Thus, the movement of water into and out of the ventricles may be determined by the osmotic load of the CSF. If osmotic load determines the aqueous content of CSF in this manner, it is reasonable to hypothesize that hydrocephalus may be precipitated by pathologies and/or insults that produce sustained elevations of osmotic content within the ventricles. Methods We investigated this hypothesis by manipulating the osmotic content of CSF and assaying the development of hydrocephalus in the rat brain. This was achieved by continuously infusing artificial CSF (negative control; group I, fibroblast growth factor (FGF2 solution (positive control; group II and hyperosmotic dextran solutions (10 KD and 40 KD as experimental solutions: groups III and IV for 12 days at 0.5 μL/h. The osmolality of the fluid infused was 307, 664, 337 and 328 mOsm/L in Groups I, II, III and IV, respectively. Magnetic resonance imaging (MRI was used to evaluate the ventricular volumes. Analysis of variance (ANOVA with pairwise group comparisons was done to assess the differences in ventricular volumes among the four groups. Results Group I had no hydrocephalus. Group