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J Shou

Publications and source records attributed to J Shou.

At least 55 records · Page 3Linked to original sources

Interleukin 1 and its relationship to endotoxin tolerance.

Endotoxin (lipopolysaccharide [LPS])-induced cytokine release has been implicated in the pathogenesis of sepsis. Sublethal doses of LPS induce tolerance to a septic insult. This study evaluated pretreatment with interleukin 1 (IL-1) against an LPS challenge and examined its relationship to endotoxin tolerance. C3H/HeN mice (N = 100) were injected intraperitoneally with phosphate-buffered saline (control group), IL-1 (200 micrograms/kg), or LPS (1 mg/kg) for 3 days. On day 5, peritoneal macrophages were harvested and assayed for antimicrobial activity (superoxide anion production and Candida albicans phagocytosis). Serum cytokine levels and survival after an LPS challenge on day 5 were also assessed. Pretreatment with IL-1 or LPS significantly increased superoxide anion production, C albicans phagocytosis, and survival compared with pretreatment with phosphate-buffered solution. Interleukin 6 levels significantly decreased in the IL-1 and LPS groups. Peak levels of tumor necrosis factor significantly decreased only in the LPS group. Thus, pretreatment with IL-1 or low doses of LPS may exert protective effects by decreasing levels of interleukin 6 while increasing antimicrobial activity. Mice pretreated with IL-1 were protected from endotoxin despite elevated peak levels of tumor necrosis factor, suggesting a different mechanism for endotoxin tolerance than for tolerance to tumor necrosis factor.

Animals↗

Anti-neoplastic effects of interleukin-4.

Interleukin-4 (IL-4) is a cytokine, with potential anti-neoplastic effects. This study examined the effects of IL-4 on host anti-tumor responses in a murine model. C57/B16 mice (n = 40) were randomized to receive Lewis lung carcinoma (10(6) cells: right flank; sc) or saline, and sacrificed 10 days postinoculation for assessment of peritoneal macrophage (PMO) anti-tumor mechanisms [superoxide anion generation (O2-), tumor necrosis factor (TNF), and TNF-independent (P815) cytotoxicity], splenocyte mixed lymphocyte response (MLR) (Balb/c stimulator), and cytotoxic lymphocyte generation (CTL against P815). Cells were cultured +/- IL-4 (100 U/ml). In a second study, 20 mice received Lewis lung implants (sc) and were randomized on Day 21 to receive daily IL-4 (1000 U/mouse; ip) or saline. Tumor volumes and median survival were assessed. Tumor necrosis factor-independent cytotoxicity (O2-, MLR and CTL) was impaired in the tumor-bearing (TB) study group. Interleukin-4 administered to cultured cells from TB mice enhanced O2-, as well as MLR and CTL (P less than 0.01), and decreased TNF release but did not alter PM phi TNF-independent anti-tumor responses (P815). In vivo administration of IL-4 significantly decreased tumor growth (P less than 0.05) after 10 days of treatment and significantly prolonged median host survival (P less than 0.05). These findings indicate the therapeutic potential of IL-4 in the TB host which may function through downregulation of TNF production while potentiating certain T cell-dependent and independent anti-tumor immune mechanisms.

Animals↗

Enteral nutrition with supplemental arginine, RNA, and omega-3 fatty acids in patients after operation: immunologic, metabolic, and clinical outcome.

The individual nutrients arginine, RNA, and omega-3 fatty acids improve immune function, but prospective trials have not demonstrated their effects on clinical outcome. Patients (n = 85) who underwent operation for upper gastrointestinal malignancies were randomized to receive the supplemental diet or a standard enteral diet after surgery. Clinical patient characteristics were similar between the two groups. Mean caloric intakes (1421 vs 1285 kcal/day) were similar between groups. Mean nitrogen intakes (15.6 vs 9.0 gm/day) and nitrogen balances (-2.2 vs -6.6 gm/day) measured in the first 20 patients were significantly greater in the supplemented group than in the standard group (p = 0.05). In vitro lymphocyte mitogenesis was measured in the first 31 patients and was decreased on postoperative day 1 in both groups, but normal levels were regained only in the supplemented group. In the cohort of 77 eligible patients, infectious and wound complications occurred significantly less often (11% vs 37%) in the supplemented group than in the standard group (p = 0.02). Linear logistic models for infectious/wound complications with control for the amount of nitrogen suggested (p = 0.10) dietary treatment as the major factor. Mean length of stay in the hospital was significantly shorter (p = 0.01) for the supplemented group (15.8 +/- 5.1 days) than for the standard group (20.2 +/- 9.4 days). These results suggest that postoperative enteral nutrition with supplemental arginine, RNA, and omega-3 fatty acids instead of a standard enteral diet significantly improved immunologic, metabolic, and clinical outcomes in patients with upper gastrointestinal malignancies who were undergoing major elective surgery.

Aged↗

Effects of laparotomy on systemic macrophage function.

Surgical trauma induces immunosuppression that may adversely influence survival. This study examined the effect of laparotomy on two different macrophage populations, peritoneal macrophages (PM phi) and Kupffer cells. Female, 6- to 8-week old, CFW/C3H-HeN mice (n = 160) were randomly allocated to one of three study groups: control, ether anesthetic only, or ether anesthetic and laparotomy. On postoperative days 1 and 3, PM phis and Kupffer cells were harvested and assayed for superoxide anion production (O2-), percent macrophage phagocytosis of Candida albicans (CAP), percent C. albicans killed by macrophages (CAK), percent major histocompatibility complex (MHC)-class II antigen expression, and antigen presentation. Macrophages isolated on postoperative day 1 were also cocultured with 100 units/10(6) cells/ml interferon-gamma (IFN-gamma). Laparotomy significantly impaired microbicidal activity (O2-, percent CAP, and percent CAK) and antigen presentation on postoperative day 1. On postoperative day 3, O2- and antigen presentation were increased significantly (p less than 0.05) over control values, indicating a rebound phenomenon. Kupffer cell microbicidal function was unchanged on postoperative days 1 and 3. The initial immune impairment (PM phis: O2-, CAP, and CAK) was abrogated by IFN-gamma treatment. In immunosuppressed hosts after injury, administration of macrophage-activating factors such as IFN-gamma could be of therapeutic benefit.

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Impaired macrophage function in severe protein-energy malnutrition.

Protein-energy malnutrition induces immunosuppression that predisposes to sepsis, but the mechanisms are unclear. This study examines the role of the macrophage in host defense in the malnourished state. Swiss-Webster mice (N = 300) were randomly allocated to control (24% casein) or low-protein (2.5% casein) diets for 8 weeks. We studied the ability of two populations of macrophages, peritoneal macrophages, and Kupffer cells to produce superoxide anion after in vivo administration of endotoxin or mycobacterium (bacille Calmette-Guérin). Phorbol diester and Candida albicans were used as stimuli. In another group of mice, we evaluated the ability of interferon gamma to up-regulate superoxide anion release and Candida phagocytosis and killing. Mice under protein-energy malnutrition demonstrated decreased mean body weights, serum protein levels, and cell yields. Superoxide anion production in resident and activated (lipopolysaccharide, interferon gamma, bacille Calmette-Guérin infection) peritoneal macrophages was significantly reduced in the malnourished group. Candida phagocytosis and killing were also both depressed in malnourished mice. Kupffer cells failed to generate superoxide anion in all groups. We conclude that severe protein-energy malnutrition significantly impairs macrophage function, which could diminish response to acute and chronic septic challenges. Interferon gamma up regulated peritoneal macrophage and Kupffer cell microbicidal function, which suggests a therapeutic role for this lymphokine in the malnourished septic host.

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Low-dose interferon gamma renders neuroblastoma more susceptible to interleukin-2 immunotherapy.

Neuroblastoma remains a common and deadly childhood tumor, resistant to both surgical and chemo/radiotherapeutic intervention in its advanced stages. The role of immunotherapy in such cancers has yet to be defined. In previous work, we found that the addition of interferon gamma (IFN-gamma) to 3-day in vitro tissue cultures of the murine neuroblastoma C1300, led not only to the tumor's increased cell surface expression of the immunologically important major histocompatibility complex (MHC) class I antigen, but also to an increased susceptibility of such modified tumor to subsequent lymphokine activated killer (LAK) cell lysis. In this study, we sought to determine the in vivo applicability of these findings. Initial dose-response studies helped define a regimen of rIFN-gamma's administration that upregulated MHC class I without activating host natural killer (NK) activity. A/J mice bearing 7-day-old subcutaneous C1300 were randomized to receive daily morning injections of either 0, 25,000, 50,000, or 100,000 U of rIFN-gamma intraperitoneally for 6 days. Animals were killed at days 3, 6, and 9 after initiation of rIFN-gamma therapy, and tumors were excised, digested, and stained for both MHC class I and II expression. At the time of sacrifice, splenocytes from each animal were tested for NK cytotoxicity toward YAC (an NK-sensitive lymphoma) and C1300. These studies defined 3 days of therapy with 25,000 U as a "priming" dose that increased expression of class I with minimal impact on NK activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

Protein-calorie malnutrition impairs host defense against Candida albicans.

Protein-calorie malnutrition (PCM) impairs immune responsiveness predisposing to Candida albicans sepsis, but mechanisms are unclear. This study examined the effect of PCM on enteric-derived C. albicans intestinal translocation and the ability of in vivo interferon-gamma (IFN-gamma) to upregulate macrophage (MO) candidacidal mechanisms in PCM mice. Control (24% casein) and low protein (2.5%) diets were given for 4 weeks. Mice (n = 160) were fed C. albicans in their drinking water for 3 days and C. albicans translocation (mean colony-forming units (CFU)/g tissue +/- SEM) to the GI tract, liver, spleen, and kidney was assessed at 1 and 5 days following endotoxin challenge of 1, 5, and 10 mg/kg body wt. In a separate study (n = 100 mice), IFN-gamma (1000-10,000 U/day ip) vs saline was given for 3 days prior to harvesting peritoneal macrophages for assay of superoxide anion (O2-), percentage macrophage phagocytosis of C. albicans, and percentage killing of C. albicans. On Day 1, fungal translocation to the intestinal wall and systemic organs in the PCM group was significantly higher. On Day 5, mean CFU were significantly higher in the PCM group, indicating impaired organ clearance. Mean O2-, phagocytosis, and killing were significantly impaired in the PCM group (P less than 0.05), but IFN-gamma improved all functions. PCM significantly depressed host responses to C. albicans. IFN-gamma treatment enhanced candidacidal mechanisms, suggesting a therapeutic role in the malnourished host predisposed to C. albicans sepsis.

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Elemental diet alters macrophage function in mice.

Administration of a chemically defined liquid elemental diet (ED) induces spontaneous bacterial translocation to mesenteric lymph nodes (MLN) in animal models. The influence of this process on host immunity is unclear. This study evaluated the effects of ED on peritoneal macrophage (PM phi) antimicrobial functions. Conventional C57/BL6 mice and endotoxin-resistant C3H/HeJ mice (n = 60) were randomized to be pair-fed either an ED or regular chow diet (RD) for 14 days. Blood, spleen, liver, and MLN were cultured for bacteria. PM phi were harvested for: percentage Candida albicans (CA) phagocytosis, percentage killing of CA, PM phi superoxide anion (O2-) production, and TNF-dependent macrophage cytotoxicity. Enteral feeding of ED in conventional C57/BL6 mice caused significant bacterial translocation to MLN but not other organs. Significant impairment of CA killing by PM phi occurred in the ED group and was associated with reduced O2- production. Tumor necrosis factor (TNF)-dependent cytotoxicity of PM phi was also decreased. In endotoxin-resistant C3H/HeJ mice, bacterial translocation was not observed and PM phi antifungal functions remained similar in both RD and ED groups. Thus, enteral feeding of an elemental diet downregulates host oxidative and antimicrobial mechanisms and TNF-dependent cytotoxicity in conventional mice which may be secondary to elemental diet-induced bacterial translocation.

Animal Feed↗

Immunosuppressive mechanisms in protein-calorie malnutrition.

Protein-calorie malnutrition (PCM) induces immunosuppression leading to increased mortality rates. Impaired macrophage respiratory burst activity (superoxide anion [O2-] generation) occurs in PCM, but cellular mechanisms are unclear. The major pathway resulting in O2- production involves inositol lipid-dependent signal transduction. This study examined the effect of mild versus severe PCM on macrophage O2- generating signal transduction pathways specific for responses to Candida albicans. Mice (CFW/Swiss Webster: n = 300) were randomized to either control or low protein diets for 3 or 8 weeks. Peritoneal macrophages were harvested for O2- production, mannose-fucose receptor (MFR) expression, membrane phospholipid analysis, arachidonic acid (AA) content, prostaglandin E2 (PGE2) production, and protein kinase C levels. O2- release was impaired in both mild and severe PCM. MFR expression was also decreased at these time points. Inositol lipid content was significantly lower at the 8-week time point only, although PGE2 and AA were significantly higher in the low protein diet group at 3 weeks. Protein kinase C levels were unchanged by PCM. Thus, mild PCM significantly increases macrophage-PGE2 production secondary to increased AA phospholipid content, with subsequent inhibition of O2- and MFR expression. Severe PCM inhibits macrophage (O2-) through depletion of critical membrane phospholipid components with subsequent impairment in signal transduction.

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Transfusion-induced immunosuppression results in diminished host survival in a murine neuroblastoma model.

Perioperative blood transfusion has been associated with decreased survival in cancer patients. The immunologic consequences of H-2 incompatible blood transfusion as related to neoplasia are unclear. This report examined the effect of multiple allogeneic blood transfusions, compared to syngeneic transfusions and saline infusion, on cellular immunity, tumor growth, and host survival in a murine C1300 neuroblastoma model. A/J mice were randomized to receive two weekly transfusions of washed whole blood cells from C57 Bl/6 or A/J donors or saline. Animals transfused with allogeneic blood, compared to syngeneic transfusions or saline infusions, had a significantly diminished lymphocyte response to mitogen (P less than 0.001), reduced donor-specific (P less than 0.001) and third party alloantigen (P less than 0.01) MLR, and reduced cytotoxicity against a natural killer (NK) cell-sensitive target (P less than 0.001). These in vitro deficits in cellular immunity correlated with a significantly greater Day 21 tumor weight to total body weight ratio in the allogeneic group (0.33) compared with the syngeneic (0.25) and saline (0.28) groups P less than 0.05). Median host survival was reduced in the allogeneic group (24 days) compared with the syngeneic (30 days) and saline (31 days) groups. There were no significant differences in cellular immunity, tumor growth, or survival between syngeneic and saline control groups. Allogeneic blood transfusion had an adverse affect on NK and T-lymphocyte function which was associated with enhanced tumor growth and reduced survival in tumor-bearing mice.

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Immunologic effects of arginine supplementation in tumor-bearing and non-tumor-bearing hosts.

Supplemental dietary arginine has anti-tumor properties but the degree and mechanisms are unclear. In non-tumor-bearing CBA/J mice (n = 60), 1% arginine supplementation significantly enhanced thymic weight, spleen cell mitogenesis, and interferon-activated natural killer cell activity; no further enhancement was observed with 2% or 4% supplementation. Supplemental 1% arginine, when compared with 1.7% glycine, enhanced interferon-induced natural killer cell activity, lymphokine-activated killer cell generation, and macrophage cytotoxicity. In A/J mice (n = 420), bearing either a moderately immunogenic (C1300) or weakly immunogenic (TBJ) murine neuroblastoma, 1% arginine significantly (p less than 0.05) retarded tumor growth and prolonged median survival time compared with glycine or no supplementation. Dietary arginine enhanced T-cell function and significantly increased responsiveness to autologous C1300 tumor in a mixed lymphocyte tumor cell culture (MLTC). The immunomodulatory effects of arginine provide nutritional and immunologic support of the tumor-bearing host and may be helpful when given concommitant with immunotherapy.

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Effect of dietary protein and amino acids on immune function.

The normal immune system has local and systemic components which are influenced by a variety of alterations. Impaired host immunity is associated with neoplasia, protein calorie malnutrition, and the administration of immunosuppressive drugs. It is well accepted that protein calorie malnutrition impairs host immunity with particular detrimental effects on the T-cell system, resulting in increased opportunistic infection and increased morbidity and mortality in hospitalized patients. Individual nutrient substrates may also have a major influence on the immune system. Individual amino acids are often described as essential, based on requirements for optimal growth and maintenance of positive N balance. Arginine has been demonstrated to be essential to the traumatized host and may have tissue-specific properties which influence components of the immune system. Thus, arginine may be of value in clinical situations where the immune system is compromised. In a series of experiments in normal animals, arginine was demonstrated to enhance cellular immune mechanisms, in particular T-cell function. It also has a marked immunopreserving effect in the face of immunosuppression induced by protein malnutrition and increases in tumor burden. In postoperative surgical patients, arginine supplementation results in enhanced T-lymphocyte response and augmented T-helper cell numbers, with a rapid return to normal of T-cell function postoperatively compared with control patients. These data suggest that arginine supplementation may enhance or preserve immune function in high-risk surgical patients and theoretically improve the host's capacity to resist infection.

Amino Acids↗

Protein-calorie malnutrition inhibits antitumor response to interleukin-2 immunotherapy.

The efficacy of systemic interleukin-2 (IL-2) immunotherapy is dependent on a competent host immune response. This study demonstrated that protein-calorie malnutrition (PCM) inhibited the generation of an antitumor response to IL-2. A/J mice received an isocaloric diet of 2.5% or 24% casein 8 weeks before inoculation with C1300 neuroblastoma cells. Three weeks later lymphocytes from tumor-bearing mice were harvested for determination of cytotoxic T-lymphocyte generation and natural killer cell cytotoxicity. PCM produced a significant reduction in total body weight (p less than 0.001) and serum albumin concentration (p less than 0.001). PCM inhibited generation of cytotoxic T lymphocytes (p less than 0.001), T-lymphocyte response in mixed lymphocyte reaction (p less than 0.001), and in vitro activation of natural killer cell cytotoxicity with IL-2 (p less than 0.001). A second experiment was performed to evaluate whether the in vitro deficits in tumor-specific and natural immunity in the animal model of PCM would diminish the efficacy of systemic high-dose IL-2 (3 x 10(6) units/kg three times daily for 5 days). The mean percent inhibition of C1300 growth with IL-2 was only 15% in mice with PCM compared with 60% in well-nourished mice (p less than 0.01). Median host survival time was greater in well-nourished animals (55 days) compared with animals with PCM (39 days) that received IL-2 (p less than 0.05). These data suggest that nutritional status is a critically important variable in tumoricidal response to systemic IL-2.

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The influence of natural killer cells in neuroblastoma.

Human neuroblastoma (NRB) cell lines are markedly sensitive to natural killer (NK) cell lysis in vitro, but patients with NRBs have low or absent NK activity. This study evaluated the NK sensitivity of murine NRBs (C1300 and TBJ) in the regulation of NRB growth and determined the effects of recombinant (r) interferon gamma and recombinant interleukin 2 (rIL-2). Both basal (8% +/- 3% specific cytotoxicity) and induced (20% +/- 3%) NK lyses of C1300-NRB were observed. In vivo depletion of NK cells with anti-asialo GM-1 significantly enhanced growth of C1300-NRB and decreased survival. Treatment with r-interferon gamma or rIL-2 on days 1 through 3 after C1300-NRB inoculation significantly prolonged the mean tumor latency period, decreased the tumor growth rate, and enhanced in vitro NK killing of C1300-NRB and YAC-1. The effects of r-interferon gamma and IL-2 were abrogated by pretreatment with anti-asialo GM-1. These results demonstrated that NK cells form one important component of regulation of a murine NRB, but immunomodulation with potent lymphokines requires cooperation of more than one cell type.

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Immune and metabolic effects of arginine in the surgical patient.

Arginine enhances immune function and promotes nitrogen retention in animal models, but its immunomodulatory effects in surgical patients are unknown. This randomized, prospective trial evaluated the immune and metabolic effects of supplemental L-arginine (25 g/day, n = 16) or isonitrogenous L-glycine (43 g/day, n = 14) in 30 cancer patients undergoing major operation. Two groups of patients received either arginine or glycine for 7 days after surgery as a supplement to a graduated enteral diet. Nitrogen balance was measured daily, and immune parameters were determined both before and after surgery, on Days 1, 4, and 7. The T-lymphocyte response to concanavalin A (con A) and PHA and dual marker phenotype analysis of lymphocyte (CD2, CD4, CD4/DR, CD8, CD8/DR) and macrophage (M3/DR) subsets were determined. Mean age, degree of preoperative weight loss, disease stage, number of perioperative transfusions, and calorie and nitrogen intake were similar for the groups studied. Mean daily nitrogen balance (-2.3 g/day in the arginine group vs. -3.9 g/day in the glycine group) was not significantly different between the two groups, but positive mean nitrogen balance was achieved only in the arginine group between Days 5 and 7 after surgery. Supplemental arginine significantly enhanced the mean T-lymphocyte response (stimulation index) to con A from 45 +/- 26 on postoperative Day 1 to 72 +/- 47 and 87 +/- 49 on postoperative Days 4 and 7, compared with the values of 29 +/- 15, 27 +/- 20, and 33 +/- 34 in the glycine group at the same time points, respectively. Supplemental arginine increased mean CD4 phenotype (% T-cells) on postoperative Days 1 and 7 from 25 +/- 9 to 43 +/- 14, compared with the values of 30 +/- 14 and 29 +/- 13 in the glycine group (p less than 0.05). The beneficial effect of arginine on the immune system appeared distinct from its more moderate effect on nitrogen metabolism. As a nutrient substrate, arginine was nontoxic, and may benefit surgical patients who are at increased risk of infection.

Aged↗

Immunomodulatory mechanisms of arginine.

Dietary supplementation with the amino acid arginine augments T-lymphocyte activation in response to mitogens in clinical and experimental studies. In experimental models arginine enhances specific T cell antitumor immunity. The mechanism of these immunostimulatory effects of arginine on T cell function is unclear, and the scope and specificity of arginine's influence on other components of the effector immune response such as natural killer (NK) cells and macrophages are unknown. To evaluate the role of arginine in these responses, CBA/J mice (n = 100) were randomized to receive either 1% arginine supplementation or isonitrogenous (1.7%) glycine supplementation for at least 10 days. There was no significant differences in mean body weight between groups during feeding. Arginine supplementation significantly (p less than 0.05) enhanced cytotoxic T-lymphocyte development, poly IC-inducible NK activity, and the kinetics of interleukin-2 receptor expression on activated T cells. Basal- and endotoxin-induced macrophage interleukin-1 and superoxide production were not significantly influenced by supplemental arginine although macrophage cytotoxicity in response to gamma-interferon was augmented (p = 0.07). In subsequent in vitro studies we established that certain effects (NK, cytotoxic T-lymphocyte, and T cell activation) were reproducible after preincubation for 72 hours in pharmacologic levels of arginine. The data strongly suggest that arginine mediates a direct effect on components of the immune system, which results in enhanced production or use of lymphokines.

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Beneficial effect of enteral glycine in intestinal ischemia/reperfusion injury.

It has been shown in vitro that glycine can protect renal tubules and hepatocytes from hypoxic injury. Glycine also attenuates ischemic injury in transplanted livers. The present study investigated the effect of enteral glycine in a murine model of ischemia/reperfusion injury of the small intestine. Mice (n = 12 in each group) were randomized to receive two gastric gavages of either a 20% glycine (Gly) or 23% balanced amino acid (AA) solution with a 6-hour interval between each gavage. One hour after the second gavage, mice underwent superior mesenteric artery clamping for 20 minutes. The clamp was then released for reperfusion. Another group of mice (n = 8) underwent a sham operation and served as additional control animals. Six hours after ischemia/reperfusion, the mice were killed in order to assess the intestinal injury (intestinal protein content, mucosal disaccharidase activity, and intestinal histologic findings) and the systemic consequences (bacterial translocation, serum interleukin-6, and lung myeloperoxidase activity). A second set of mice (n = 55) underwent identical gavages and ischemia/reperfusion and they were followed for survival. Compared to AA, enteral glycine administered prior to intestinal ischemia/reperfusion injury significantly preserved mucosal indices and intestinal histology and decreased lung myeloperoxidase activity. Survival was also significantly increased in animals receiving glycine compared to AA control mice. These data suggest that enteral glycine supplementation may be beneficial in attenuating intestinal ischemia/reperfusion injury and its related systemic effects in this murine model.

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