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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of induction of an acute-phase response and its mediators on the development of liver schizonts of the rodent malaria parasite Plasmodium berghei was investigated in Brown Norway rats. Subcutaneous injection of turpentine oil 24 h or 5 min before inoculation of sporozoites resulted in 80% and 35% reduction of schizont development, respectively. Turpentine oil induced high plasma levels of interleukin-6 (IL-6). Intraperitoneal administration of IL-1, IL-6 or both, significantly reduced liver schizont development. This reduction was also present if IL-6 had been administered 24 h after sporozoite inoculation. Inhibition induced by IL-1 could be prevented by simultaneous administration of polyclonal anti-IL-6. Administration of polyclonal anti-IL-6 without IL-1 resulted in a 40% increase of liver schizonts compared to control animals. We conclude that induction of an acute-phase response during experimental Plasmodium berghei infections in Brown Norway rats, strongly inhibits liver schizont development and that IL-6 is a key mediator in this process.
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PMID:Cytokines inhibit the development of liver schizonts of the malaria parasite Plasmodium berghei in vivo. 151 19

Endothelial monolayers were prepared from neonatal heart or liver tissue of Lewis (Le) rats. Cells in their first passage of culture were used to investigate the short-term (1 hr at 37 degrees) binding of 51Cr-labelled Le rat lymphocytes prepared from the mesenteric lymph node (MLN), peripheral lymph node (PLN) or Peyer's patches (PP) to those endothelia, or the activation by concanavalin A (Con A) or irradiated (Lewis x Brown Norway)F1 (LBNF1), of Le cells on the monolayers after 84 hr in culture. MLN and PP showed preferential binding to, and activation on, liver endothelium compared with heart endothelium (approximately twofold difference), while the converse was seen with PLN. No inhibition of binding was seen with antibodies to intracellular adhesion molecule-1 (ICAM-1) or lymphocyte function-associated antigen-1 (LFA-1). Preincubation of endothelial cells with plasma isolated from the portal or hepatic vein of normal adult mice (5% plasma, 37 degrees for 14 hr) caused a 1.5-2-fold stimulation of binding of MLN/PP to heart endothelium, which was inhibited (> or = 75%) by anti-ICAM-1 or anti-LFA-1, and a fourfold stimulation of binding to liver endothelium, which was not inhibited by these monoclonal antibodies (< or = 25% inhibition). In contrast, antibodies to tumour necrosis factor-alpha (TNF-alpha) or interleukin-6 (IL-6) caused inhibition of activation of liver endothelium (> or = 75%), while producing little affect on activation of heart endothelium. Similar results were seen when lymphocyte activation on endothelial cells rather than adhesion cells was investigated. Our data suggest a heterogeneity in lymphocyte-endothelial interactions, which is further regulated, under physiological conditions, by the liver.
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PMID:Hepatic regulation of lymphocyte adhesion to, and activation on, syngeneic endothelial monolayers. 782 67

Rejection continues to be a major cause of graft loss in small intestine transplantation (SIT). We have studied, by semiquantitative reverse transcriptase PCR (rtPCR), the intragraft expression of cytokines relevant to rejection in a rat model. Heterotopic SIT grafts were performed from Lewis x Brown Norway F1 donors into Lewis recipients. The isograft control was Lewis into Lewis. Five animals in each isograft and allograft group were sacrificed on POD 3, 5, 7, 8, 9, 10, 12, and 14. mRNA was isolated from portions of the terminal ileum and rtPCR performed to amplify message for interleukin-2 (IL-2), IL-2 receptor (IL-2R), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma). Semiquantitative analysis was performed using 32P radionuclide incorporation and scintillation counting. The results were expressed as percent activity compared with beta-actin. Histologic correlation with cytokine expression was made. On POD 3 after SIT there was no evidence of rejection by histology and all cytokines studied showed no difference between the isograft and the allograft. On POD 5 the first evidence of mild rejection was seen on histology and IL-6, IFN-gamma, TNF-alpha showed a significant up regulation in the allograft that persisted through POD 14. mRNA for IL-2 was not significantly upregulated until POD 7 and persisted until POD 14. IL-2R was constitutively expressed in both isograft and allograft and was not a reliable predictor of rejection. Histologic rejection was moderately severe by POD 7 and severe between POD 8 and 14 correlating with the increasing expression of IL-6, IFN-gamma, and TNF-alpha. In summary, we have shown that increasing expression of mRNA for IL-6, IFN-gamma, and TNF-alpha not only correlated with severity of rejection but that upregulation began early when histologic evidence of rejection first occurred.
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PMID:The correlation of intragraft cytokine expression with rejection in rat small intestine transplantation. 794 Jun 88

We investigated the development of exoerythrocytic forms (EEF) of Plasmodium berghei in livers of normal and macrophage-depleted Brown Norway rats. Macrophages were depleted by use of liposome-encapsulated dichloromethylene diphosphonate. Upon inoculation of sporozoites, macrophage-depleted rats had significantly larger numbers of EEF than untreated rats. We also investigated the effect of macrophage impairment by silica treatment on the development of EEF and confirmed that silica induces a significant reduction of EEF development. Intravenous administration of silica induced high levels of interleukin-6 in plasma within a few hours. The seemingly contradictory results for EEF development may be explained by our previous observation that interleukin-6 strongly inhibits sporozoite penetration and EEF development in vivo. We conclude that in experimental infections with sporozoites, Kupffer cells inhibit rather than enhance EEF development.
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PMID:Kupffer cell elimination enhances development of liver schizonts of Plasmodium berghei in rats. 838 4

The present study examined stressor interactions with genotype and light/dark cycle. Male Brown Norway (BN), Fischer 344 (F344), Lewis (from two different vendors: Lew/CR and Lew/H) and Sprague Dawley (SD) rats were exposed to footshock either in the early light or early dark circadian phase. Immediately after footshock, the spleen and whole blood proliferation to PHA and Con A was assessed. To provide endocrine indices of stress, serum was measured for corticosterone and interleukin-6 (IL-6). All rats showed significant increases in serum corticosterone and IL-6 following footshock either in the light or the dark. Rat strain differences were noted in the IL-6 response, while the corticosterone response was strong for all strains. The criterion for 'suppression' of lymphocyte proliferation was p < .05 (as determined by ANOVA) compared to non-shocked controls. Spleen: with the exception of BN rats, the other strains showed suppressed spleen cell proliferation to PHA and Con A both in the light and the dark. BN rats failed to show suppression of mitogenic activity to PHA when footshock was given in the light. Peripheral blood lymphocytes: suppression in Lew rats from either vendor, and in F344 and BN rats, did not vary with time of day nor with the type of mitogen tested. SD rats did not show suppression to PHA if shocked in the light. These results highlight the generality of stressor-induced mitogenic lymphocyte proliferation during the early diurnal and nocturnal periods of the day.
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PMID:Suppression of lymphocyte mitogenesis in different rat strains exposed to footshock during early diurnal and nocturnal time periods. 883 90

We studied the applicability of interleukin-6 Pseudomonas exotoxin fusion protein (IL-6PE4E) for treatment of acute myelocytic leukemia (AML). Leukemic cells from five out of 10 AML patients studied expressed IL-6 receptor (IL-6R) and proliferation in vitro was inhibited in four of these cases. The potential of this approach in vivo was tested in a pre-clinical model for AML; the Brown Norway acute myelocytic leukemia (BNML). To obtain IL-6R expression levels on BNML cells comparable to the numbers expressed on human AML, human IL-6R gene transfectants of the BNML sub-line LT12 (LT12/IL-6R) were generated. IL-6PE4E is cytotoxic in vitro to LT12/IL-6R expressing 1400 high affinity IL-6R per cell with 50% inhibition of DNA synthesis at 1 ng/ml. In vivo treatment of leukemic rats carrying LT12/IL-6R leukemia indicated that the maximal tolerated dose of IL-6PE4E was 275 +/- 25 microg/kg/day, when continuously administered for 7 days and resulted in a 90% reduction in leukemic cell load. At this dose level of IL-6PE4E no reduction of normal hemopoietic progenitors was seen in non-leukemic rats. At higher dose levels (350-1050 microg/kg/day) severe systemic toxicity was encountered. On the basis of these pre-clinical studies the feasibility of growth factor-toxins for selective in vivo targeting to AML cells is evaluated.
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PMID:Treatment of acute myelocytic leukemia with interleukin-6 Pseudomonas exotoxin fusion protein in a rat leukemia model. 889 84

Caloric restriction has been shown to alter a broad range of immunological end points in both experimental animals and humans. The objective of this study was to investigate the effect of short-term moderate feed restriction (25% reduction) on allergic immune responses in Brown Norway rats. After 3 weeks of acclimation to their feed regimens, rats were sensitized and 2 weeks later challenged with house dust mite (HDM) antigen via intratracheal instillation. Feed restriction resulted in lower levels of antigen-specific IgE in serum and reduced antigen specific lymphoproliferative activity in pulmonary lymph nodes. Feed restriction also attenuated pulmonary inflammation, as evidenced by lower levels of lactate dehydrogenase and total protein, decreased infiltration of neutrophils and eosinophils, and reduced secretion of pro-inflammatory cytokine tumor necrosis factor (TNF)-[alpha] in bronchoalveolar lavage fluid. In addition, feed restriction decreased TNF-[alpha] secretion in serum and decreased mRNA expression of TNF-[alpha] and interleukin-6 in pulmonary lymph nodes. We conclude that feed restriction strongly dampened the allergic immune responses to HDM in rats and that this attenuation was associated with decreased expression and secretion of pro-inflammatory cytokines.
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PMID:Attenuated allergic responses to house dust mite antigen in feed-restricted rats. 1113 91

We investigated whether caloric restriction (CR) improves physical performance in a rodent model of aging, and whether this effect is accompanied with a decrease in visceral adipose tissue production of proinflammatory cytokines. Body composition, standardized physical performance measures, as well as in vitro visceral adipose tissue cytokine secretion and circulating levels of an inflammatory marker were cross-sectionally assessed in ad libitum (AL)-fed and lifelong CR Fischer 344 x Brown Norway male rats aged 18, 24, and 29 months. Fat to lean mass ratio increased and physical performance declined with age in the AL rats. Compared to AL rats, CR rats had lower fat mass, fat to lean ratio, adipose tissue secretion of interleukin-6, and circulating levels of C-reactive protein, and higher physical performance scores. Therefore, CR may be an effective intervention for improving functional status into advanced age and is perhaps mediated via a reduction in adipose tissue-generated proinflammatory cytokine production.
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PMID:Lifelong caloric restriction and interleukin-6 secretion from adipose tissue: effects on physical performance decline in aged rats. 1792 19

White adipose tissue is recognized as both a site of energy storage and an endocrine organ that produces a myriad of endocrine factors called adipokines. Brown adipose tissue (BAT) is the main site of nonshivering thermogenesis in mammals. The amount and activity of brown adipocytes are associated with protection against obesity and associated metabolic alterations. These effects of BAT are traditionally attributed to its capacity for the oxidation of fatty acids and glucose to sustain thermogenesis. However, recent data suggest that the beneficial effects of BAT could involve a previously unrecognized endocrine role through the release of endocrine factors. Several signaling molecules with endocrine properties have been found to be released by brown fat, especially under conditions of thermogenic activation. Moreover, experimental BAT transplantation has been shown to improve glucose tolerance and insulin sensitivity mainly by influencing hepatic and cardiac function. It has been proposed that these effects are due to the release of endocrine factors by brown fat, such as insulin-like growth factor I, interleukin-6, or fibroblast growth factor-21. Further research is needed to determine whether brown fat plays an endocrine role and, if so, to comprehensively identify which endocrine factors are released by BAT. Such research may reveal novel clues for the observed association between brown adipocyte activity and a healthy metabolic profile, and it could also enlarge a current view of potential therapeutic tools for obesity and associated metabolic diseases.
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PMID:An endocrine role for brown adipose tissue? 2383 24

The effect of different dietary levels of selenium (Se) and vitamin E on egg production, the antioxidant status and the immune system response of hens was investigated in the current study. A total of 32 Lohman Brown hens were divided into four groups and were fed diets with 5% of soybean oil and two levels of Se (0.15 and 0.30 mg/kg) and vitamin E (30 and 60 mg/kg). During 10 weeks of experimental feeding, the body weights of hens and egg production were similar in all dietary treatments, but a higher Se content of diets contributed to a significant increase in egg weight. A higher vitamin E level significantly increased alpha-tocopherol concentrations (2.71 vs. 2.05 microg/mL, p = 0.001), superoxide dismutase (SOD) activity (43.3 vs. 39.9 U/mL, p = 0.049) and the ferric reducing ability of serum (FRAP) (123.0 vs. 105.7 micromol/L, p = 0.029). A higher Se content increased the concentrations of ascorbic acid (0.309 vs. 0.073 microg/L, p = 0.001), retinol (1.48 vs. 1.15 microg/mL, p = 0.001) and alpha-tocopherol (2.86 vs. 1.90 microg/mL, p = 0.001), the activity levels of catalase (3.40 vs. 2.98 U/L,p = 0.010) and SOD (43.4 vs. 30.8 U/mL, p = 0.040) as well as the total antioxidant status (TAS) of serum (0.38 vs. 0.28 mmol/L, p = 0.026). There were no significant differences in the concentrations of tumor necrosis factor-alpha (TNF-a) and interleukin-6 (IL-6) between treatments, while a higher vitamin E content of diets increased serum immunoglobulin A (IgA) concentrations (370.6 vs. 321.3 microg/mL, p = 0.026). Higher dietary levels of vitamin E and Se increased the serum concentrations of retinol (1.66 vs. 2.20 microg/mL, p = 0.013) and a-tocopherol (3.33 vs. 1.71, p = 0.014), but they had no effect on the other physiological parameters. It is recommended that the levels of both supplements, Se and vitamin E, be increased in laying hen diets as they have a beneficial effect on the serum concentrations of retinol and alpha-tocopherol.
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PMID:The effect of different dietary levels of vitamin E and selenium on antioxidant status and immunological markers in serum of laying hens. 2397 Dec 2


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