Navegando por Palavras-chave "tumor necrosis factor-alpha"

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    Effect of cyclosporin A on nitric oxide production in cultured LLC-PK1 cells
    (Marcel Dekker Inc, 2001-01-01) Lima, R.; Serone, A. P.; Schor, N.; Higa, EMS; Universidade Federal de São Paulo (UNIFESP)
    The effect of Cyclosporin A on nitric oxide production was studied in cultured LLC- PK1 cells. for this purpose the cells were incubated with vehicle (olive oil, 10 mug/ml in DMSO), Cyclosporin A (CsA, 10 mug/ml), tumor necrosis factor (TNF-alpha, 150 U/ml) + interferon (IFN-gamma, 500 U/ml) to upregulate NOS synthesis, and therefore, NO production (used as a positive control), or CsA + TNF-alpha + IFN-gamma. After 72 hours the culture medium was collected and nitrite was determined by the Griess method. the results were normalized to the protein harvested from these cells as measured by the Lowry method. Viability was determined by the exclusion of the fluorescent dyes (acridine orange and ethidium bromide). Intracellular calcium was measured spectrophotometrically using the fluorescent calcium indicator fura-2 AM. in CsA treated cells, the nitrite (pmoles/mg of protein) was decreased when compared to control (12.8 +/- 0.5 vs. 18.3 +/- 0.6; p < 0.05; both n = 8). TNF- + IFN-gamma increased the nitrite synthesis (52.0 +/- 0.2; p < 0.05 vs. control; n = 6). This effect was decreased significantly by the simultaneous treatment with CsA (38.8 +/- 0.3; p < 0.05; n = 6). Cell viability in CsA group was decreased when compared to the cdntrol (84.7 +/- 0.2% vs. 93.6 +/- 0,1%; p < 0.05: both n = 10). TNF- +/- IFN-gamma had no effect on viability (93.0 +/- 0.3%; n = 10). However, when combined with CsA, viability was decreased relative to the control (85.0 +/- 0.2%; p < 0.05; n = 10). Acute (1 h) or chronic (72 h) treatment of LLC- PK1 cells with CsA had no effect on basal calcium levels.Our results demonstrate a reduced level of nitric oxide production in LLC- PK1 cells treated with CsA. There was no effect of the drug on intracellular calcium levels, however CsA treatment did reduce cellular viability. We suggest that, in part, the decreased levels of NO production are a secondary consequence of direct cell damage. However, CsA may also be exerting direct effects on NO synthesis through its interactions with both iNOS and cNOS. These results also provide a dual mechanism of action for CsA induced nephrotoxicity, that is, direct cell damage and interference with the NO system within the nephron.
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    Injury switches melatonin production source from endocrine (pineal) to paracrine (phagocytes) - melatonin in human colostrum and colostrum phagocytes
    (Blackwell Publishing, 2006-09-01) Pontes, Gerlandia N.; Cardoso, Elaine C.; Carneiro-Sampaio, Magda M. S.; Markus, Regina P.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    A large number of data show that melatonin has immunomodulatory properties and is produced by immunocompetent cells; also, some evidence suggests a 'feedback' of the activated immune system on the pineal gland. in this paper, we studied immune-pineal interactions in colostrum obtained from healthy puerperae and mothers with mastitis taking into account that, (a) melatonin levels in milk reflects pineal activity and (b) colostrum quiescent mononuclear and polymorphonuclear phagocytes from healthy mothers in culture are adequate for evaluating the ability of immunocompetent cells to produce melatonin. Here we compared the diurnal and nocturnal melatonin levels in colostrum from healthy puerperae and mothers with mastitis; this is a unique noninvasive model for determining pineal activity in the proinflammatory phase of a defense response. in addition, we determined the 'in vitro' production of melatonin by colostrum immunocompetent cells stimulated by enteropathogenic Escherichia coli or zymosan. Suppression of nocturnal melatonin rise in mothers with mastitis was highly correlated with increased tumor necrosis factor-alpha (TNF-alpha) secretion. This result, interpreted taking into account the presence of the transcription factor nuclear factor kappa B in pineal gland, suggest that the proinflammatory cytokine can inhibit nocturnal pineal melatonin production. On the other hand, stimulated, but not quiescent, immunocompetent cells secreted in the colostrum produced melatonin in vitro. in addition, this production ceases after bacteria killing. These results suggest that during the response to an injury the production of melatonin can be transiently shifted from an endocrine (pineal) to a paracrine (immunocompetent cells) source.
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    Lower cytokine secretion ex vivo by natural killer T cells in HIV-infected individuals is associated with higher CD161 expression
    (Lippincott Williams & Wilkins, 2009-09-24) Snyder-Cappione, Jennifer E.; Loo, Christopher P.; Carvalho, Karina I. [UNIFESP]; Kuylenstierna, Carlotta; Deeks, Steven G.; Hecht, Frederick M.; Rosenberg, Michael G.; Sandberg, Johan K.; Kallas, Esper Georges [UNIFESP]; Nixon, Douglas F.; Univ Calif San Francisco; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Karolinska Univ Hosp; San Francisco Gen Hosp; Albert Einstein Coll Med
    Objective: Natural killer T (NKT) cells are efficiently targeted by HIV and severely reduced in numbers in the circulation of infected individuals. the functional capacity of the remaining NKT cells in HIV-infected individuals is poorly characterized. This study measured NKT cell cytokine production directly ex vivo and compared these responses with both the disease status and NKT subset distribution of individual patients.Methods: NKT cell frequencies, subsets, and ex-vivo effector functions were measured in the peripheral blood mononuclear cells of HIV-infected patients and healthy controls by flow cytometry. We measured cytokines from NKT cells after stimulation with either a-galactosyl ceramide-loaded CD1d dimers (DimerX-alpha GalCer) or phorbol myristate acetate and ionomycin.Results: the frequencies of NKT cells secreting interferon-gamma and tumor necrosis factor-alpha were significantly lower in HIV-infected patients than healthy controls after DimerX-alpha GalCer treatment, but responses were similar after treatment with phorbol myristate acetate and ionomycin. the magnitude of the interferon-gamma response to DimerX-alpha GalCer correlated inversely with the number of years of infection. Both interferon-gamma and tumor necrosis factor-alpha production in response to DimerX-alpha GalCer correlated inversely with CD161 expression.Conclusion: the ex-vivo Th1 responses of circulating NKT cells to CD1d-glycolipid complexes are impaired in HIV-infected patients. NKT cell functions may be progressively lost over time in HIV infection, and CD161 is implicated in the regulation of NKT cell responsiveness. (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins
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    Pineal melatonin and the innate immune response: the TNF-alpha increase after cesarean section suppresses nocturnal melatonin production
    (Blackwell Publishing, 2007-11-01) Pontes, Gerlandia N.; Cardoso, Elaine C.; Carneiro-Sampaio, Magda M. S.; Markus, Regina P. [UNIFESP]; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The nocturnal surge of melatonin is the endocrine expression of the circadian system and is essential for organizing the timing of various endogenous processes. Previous works suggest that, in the beginning of a defense response, the increase in circulating tumor necrosis factor-alpha (TNF-alpha) leads to a transient block of nocturnal melatonin production and promotes a disruption of internal time organization. in the present paper, the concentration of melatonin and cytokines [TNF-alpha, interferon-gamma (IFN-gamma), interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12] in the colostrum (postdelivery day 3) and in the milk (postdelivery days 10, 15, 20 and 30) obtained at midday and midnight from mothers who gave birth by vaginal or cesarean section were compared. the nocturnal melatonin surge observed 3 days after vaginal delivery was absent after cesarean section. IL-12 presented no daily variation in either case, while daily variations in IFN-gamma, IL-10, IL-4 and IL-5 were observed after vaginal delivery and cesarean section. On the other hand, the increase in TNF-alpha after cesarean section resulted in suppression of the nocturnal melatonin surge. Daily variation of IL-2 was only observed after recovery of the nocturnal melatonin surge, 30 days after cesarean section. the present paper supports the hypothesis of a cross-talk between the pineal gland and the immune system, which could represent a putative immune-pineal axis.