Dentin sialoprotein and phosphoprotein induce neutrophil recruitment: a mechanism dependent on IL-1beta, TNF-beta, and CXC chemokines

Dentin is a reservoir of several potentially active molecules, and dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) are the two major non-collagenous proteins. It has been established that dentin molecules are released as a consequence of osteoclast action during the resorption process. Along with osteoclasts, inflammatory cells seem to play an important role at sites of root resorption. Although the role of dentin molecules in dentinogenesis is well known, their role in pathological processes associated with dentin matrix dissolution is unclear. Recent studies have suggested that dentin components may function as chemotactic and activator signals for inflammatory cells at these sites. Herein we present evidence that demineralized dentin crude extract, DSP, and DPP induced doseand time-dependent neutrophil migration into the peritoneal cavity of mice and that this activity was inhibited by dexamethasone, but not by indomethacin or MK886. The blockade of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) receptors inhibited neutrophil accumulation. The neutrophil migration was also diminished in the absence of the chemokines cytokine-induced neutrophil chemoattractant (KC) and macrophage inflammatory protein-2 (MIP-2), but not in the absence of macrophage inflammatory protein-1alpha (MIP-1alpha). These results demonstrate that dentin induces neutrophil migration via the synthesis of IL-1beta, TNF-alpha, and chemokines and they suggest that dentin matrix proteins may have an active role in inflammatory cell recruitment during pathological processes associated with dentin and bone matrix dissolution.

Natural product inhibitors of ovarian neoplasia

The present work constitutes a review of the literature on natural products with potential antitumor activity against ovarian neoplasias. The review refers to five plant extracts and sixty-nine compounds isolated from higher plants and microorganisms, which are classified in appropriate chemical groups and model tested, and cites their activity. Some aspects of recent research with natural products directed to ward producing drugs which are inhibitors of ovarian neoplasia are discussed.

Leukotriene B(4) induces nitric oxide synthesis in Trypanosoma cruzi-infected murine macrophages and mediates resistance to infection

The production of nitric oxide (NO) by gamma interferon (IFN-gamma)-activated macrophages is a major effector mechanism during experimental Trypanosoma cruzi infection. In addition to IFN-gamma, chemoattractant molecules, such as platelet-activating factor (PAF) and CC chemokines, may also activate macrophages to induce NO and mediate the killing of T. cruzi in an NO-dependent manner. Here we investigated the ability of leukotriene B(4) (LTB(4)) to induce the production of NO by macrophages infected with T. cruzi in vitro and whether NO mediated LTB(4)-induced parasite killing. The activation of T. cruzi-infected but not naive murine peritoneal macrophages with LTB(4) induced the time- and concentration-dependent production of NO. In addition, low concentrations of LTB(4) acted in synergy with IFN-gamma to induce NO production. The NO produced mediated LTB(4)-induced microbicidal activity in macrophages, as demonstrated by the inhibitory effects of an inducible NO synthase inhibitor. LTB(4)-induced NO production and parasite killing were LTB(4) receptor dependent and were partially blocked by a PAF receptor antagonist. LTB(4) also induced significant tumor necrosis factor alpha (TNF-alpha) production, and blockade of TNF-alpha suppressed LTB(4)-induced NO release and parasite killing. A blockade of LTB(4) or PAF receptors partially inhibited IFN-gamma-induced NO and TNF-alpha production but not parasite killing. Finally, daily treatment of infected mice with CP-105,696 was accompanied by a significantly higher level of blood parasitemia, but not lethality, than that seen in vehicle-treated animals. In conclusion, our results suggest a role for LTB(4) during experimental T. cruzi infection. Chemoattractant molecules such as LTB(4) not only may play a major role in leukocyte migration into sites of inflammation in vivo but also, in the event of an infection, may play a relevant role in the activation of recruited leukocytes to kill the invading microorganism in an NO-dependent manner.

Involvement of NO in the failure of neutrophil migration in sepsis induced by Staphylococcus aureus

1. Sepsis induced by S. aureus was used to investigate whether neutrophil migration failure to infectious focus correlates with lethality in Gram-positive bacteria-induced sepsis in mice. 2. By contrast with the sub-lethal (SL-group), the lethal (L-group) intraperitoneal inoculum of S. aureus caused failure of neutrophil migration (92% reduction), high CFU in the exudate, bacteremia and impairment of in vitro neutrophil chemotactic activity. 3. Pre-treatments of L-group with adequate doses of aminoguanidine prevented the neutrophil migration failure and improved the survival of the animals (pre-treated: 43%; untreated: 0% survival). Thus, the impairment of neutrophil migration in the L-group appears to be mediated by nitric oxide (NO). 4. The injection of S. aureus SL-inoculum in iNOS deficient (-/-) or aminoguanidine-treated wild-type mice (pre- and post-treatment), which did not present neutrophil migration failure, paradoxically caused severe peritonitis and high mortality. This fact is explainable by the lack of NO dependent microbicidal activity in migrated neutrophils. 5. In conclusion, although the NO microbicidal mechanism is active in neutrophils, the failure of their migration to the infectious focus may be responsible for the severity and outcome of sepsis.

The Cancer Informatics Infrastructure (CII): an architecture for translating clinical research into patient care

Today, the clinical trial process remains slow and paper-based. The creation of a Cancer Informatics Infrastructure (CII) can provide the architectural base across the continuum of cancer research and cancer care. Recommendations of a Long Range Planning Committee identified near-term activities for the Office of Informatics at the National Cancer Institute (NCI). These include participating in national standards development; fostering oncology-related terminology and standards, e.g., Common Data Elements (CDEs); and leveraging mainstream informatics and Internet technologies, using the successful Internet model that focuses on facilitating stakeholder participation, sponsoring the CII rather than subsidizing it, and providing a test bed as well as an infrastructure. Diffusion tactics include extending the CII concept beyond its "early adopters" to the wider community through recommendations for the near-term and development of a major document defining next-phase activities.

Tumour necrosis factor-alpha and leukotriene B(4) mediate the neutrophil migration in immune inflammation

1. We investigated the mediators responsible for neutrophil migration induced by ovalbumin (OVA) in immunized mice and the mechanisms involved in their release. 2. OVA administration promoted dose- and time-dependent neutrophil migration in immunized, but not in non-immunized mice, which was mediated by leukotriene B(4) (LTB(4)) and tumour necrosis factor (TNF)alpha, since it was inhibited by LTB(4) synthesis inhibitor (MK 886) or by LTB(4) receptor antagonist (CP 105,696), by dexamethasone and by antiserum to TNFalpha (82, 85, 63 and 87%, respectively). Confirming TNFalpha involvement, OVA challenge in immunized p55 TNF receptor deficient mice (p55(-/-)) did not promote neutrophil migration (control: 2.90 +/- 0.68; p55(-/-): 0.92+/-0.23 x 10(6) neutrophils cavity(-1)). 3. OVA-stimulated peritoneal cells from immunized mice released a neutrophil chemotactic factor which mimicked, in naive mice, neutrophil migration induced by OVA. 4. Supernatant chemotactic activity is due to TNFalpha and LTB(4), since its release was inhibited by MK 886 (93%) and dexamethasone (90%), and significant amounts of these mediators were detected. 5. TNFalpha and LTB(4) released by OVA challenge seem to act through a sequential mechanism, since MK 886 inhibited (88%) neutrophil migration induced by TNFalpha. Moreover, peritoneal cells stimulated with TNFalpha released LTB(4). 6. CD(4)(+) T cells are responsible for TNFalpha release, because the depletion of this subset prevented the release of TNFalpha (control: 400 +/- 25; immunized: 670 +/- 40; CD(4)(+) depleted: 435 +/- 18 pg ml(-1)). 7. In conclusion, neutrophil migration induced by OVA depends on TNFalpha released by CD(4)(+) cells, which acts through an LTB(4)-dependent mechanism.

KM(+), a lectin from Artocarpus integrifolia, induces IL-12 p40 production by macrophages and switches from type 2 to type 1 cell-mediated immunity against Leishmania major antigens, resulting in BALB/c mice resistance to infection

The outcome and severity of some diseases correlate with the dominance of either the T helper 1 (Th1) or Th2 immune response, which is stimulated by IL-12 or IL-4, respectively. In the present study we demonstrate that gamma interferon (IFN-gamma) secretion by murine spleen cells stimulated with KM(+), a mannose-binding lectin from Artocarpus integrifolia, is due to IL-12 induction, because (1) macrophages from several sources (including cell lines) produced IL-12 p40 in response to KM(+), and (2) lectin-free supernatants from J774 cell line cultures stimulated with KM(+) induced the secretion of IFN-gamma by spleen cell cultures, an effect blocked by the supernatant pretreatment with anti-IL-12 antibody. The known pattern of susceptibility of BALB/c mice to infection with Leishmania major, attributed to high levels of IL-4 production leading to a Th2 nonprotective immune response, was modified by administration of KM(+). Draining lymph node cells from these immunized BALB/c mice (in contrast to cells from animals immunized only with soluble leishmanial antigen [SLA]) secreted high levels of IFN-gamma and low levels of IL-4, which characterized a Th1 rather than a Th2 response pattern. The footpad thickness of BALB/c mice immunized with SLA plus KM(+) and challenged with L. major was similar to that of uninfected mice. This beneficial effect against leishmanial infection was blocked by pretreatment of these mice with anti-IL-12 antibody. These observations indicate that KM(+) induces IL-12 p40 in vivo and has a protective effect against L. major infection.

Fas-FasL interaction modulates nitric oxide production in Trypanosoma cruzi-infected mice

During acute Trypanosoma cruzi infection in mice, many leucocytes undergo apoptosis. Although apoptosis has been ascribed to increased levels of nitric oxide (NO) and Fas-FasL interaction, the importance of this phenomenon in modulating the host response against T. cruzi is unknown. Herein, the role of NO- and Fas-FasL-induced apoptosis in modulating the immune response to T. cruzi was evaluated using mice deficient in Fas expression (MRL/MpJ-Fas lpr) and inducible nitric oxide synthase (iNOS) knockout mice (iNOS-/-). The results showed that besides decreasing apoptosis induction after infection, impairment of the Fas-FasL interaction resulted in decreased NO production, as a consequence of enhanced T helper 2 (Th2) cytokine production. Differently, blockage of NO-induced apoptosis resulted in uncontrolled cytokine production, rather than a biased Th2 cytokine pattern. Together, these results suggested that Fas and FasL-induced apoptosis could be implied in modulation of the immune response against T. cruzi by interfering with cytokine and NO production during the acute phase of the infection.

Modulation of chemokine production and inflammatory responses in interferon-gamma- and tumor necrosis factor-R1-deficient mice during Trypanosoma cruzi infection

Infection with Trypanosoma cruzi causes a strong inflammatory reaction at the inoculation site and, later, in the myocardium. The present study investigates the role of cytokines as modulators of T. cruzi-induced chemokine expression in vivo and in vitro. In macrophage cultures, although the stimulation with interferon (IFN)-gamma increases the expression of IP-10, it blocks KC expression. Tumor necrosis factor (TNF)-alpha, on the other hand, potentiates KC, IP-10, macrophage inflammatory protein-1alpha, and JE/monocyte chemotatic protein-1 expression. Interleukin-10 and transforming growth factor-beta inhibited almost all chemokines tested. The role of IFN-gamma and TNF-alpha in chemokine modulation during infection was investigated in T. cruzi-infected IFN-gamma-deficient (GKO) or TNF-R1/p55-deficient (p55-/-) mice. The expression of chemokines detected in the inoculation site correlated with the infiltrating cell type observed. Although GKO mice had a delayed and intense neutrophilic infiltrate correlating with the expression of KC and macrophage inflammatory protein-2, none of the above was observed in p55-/- mice. The detection of infiltrating T cells, Mig, and IP-10 in the myocardium was observed in wild-type and p55-/-, but not in GKO mice. Together, these results suggest that the regulatory roles of IFN-gamma and TNF-alpha on chemokine expression may play a crucial role in the modulation of the inflammatory response during T. cruzi infection and mediate resistance to infection.

Trypanosoma cruzi-infected cardiomyocytes produce chemokines and cytokines that trigger potent nitric oxide-dependent trypanocidal activity

BACKGROUND

The pathogenesis of myocarditis that occurs in Trypanosoma cruzi-infected mice is still poorly understood. Therefore, it is important to know the mediators that trigger leukocyte migration to the heart as well as the cellular source of these possible mediators. In this study, we investigated (1) NO synthase (NOS) induction, (2) NO synthesis, (3) trypanocidal activity, and (4) chemokine and cytokine mRNA expression by isolated cardiomyocytes infected with T cruzi.

METHODS AND RESULTS

Mouse cardiomyocytes were isolated, infected with T cruzi, and evaluated for induction of inducible NOS (iNOS), nitrite production, trypanocidal activity, and cytokine and chemokine mRNA expression. We found that T cruzi-infected murine embryonic cardiomyocytes produced nitrite and expressed mRNAs for the chemokines chemokine growth-related oncogene, monokine induced by interferon-gamma, macrophage inflammatory protein-2, interferon-gamma-inducible protein, RANTES, and monocyte chemotactic protein, for iNOS, and for the cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Separate addition of IL-1beta, interferon-gamma, TNF-alpha or monocyte chemotactic protein, macrophage inflammatory protein-2, and interferon-gamma-inducible protein, to cultured cardiomyocytes resulted in NO production but low trypanocidal activity. However, simultaneous addition of IL-1beta, interferon-gamma, and TNF-alpha or the chemokines to cultures resulted in the induction of iNOS, high levels of nitrite, and a marked trypanocidal activity. The iNOS/L-arginine pathway mediated the latter activity, inasmuch as it was inhibited by treatment with N:(G)-monomethyl-L-arginine.

CONCLUSIONS

These results indicate that iNOS activation and the proinflammatory cytokines and chemokines produced by cardiomyocytes are likely to control parasite growth and cell influx, thus contributing to the pathogenesis of chagasic cardiomyopathy seen in T cruzi-infected mice.

Kinetics of cytokine gene expression in experimental chagasic cardiomyopathy: tissue parasitism and endogenous IFN-gamma as important determinants of chemokine mRNA expression during infection with Trypanosoma cruzi

We investigated the kinetics of parasite replication, leukocyte migration, and cytokine/chemokine mRNA expression in the heart tissue from animals infected with the Colombiana strain of Trypanosoma cruzi. Cardiac tissue parasitism was noticeable at 15 days, peaked around 30 days and was dramatically reduced at 120 days postinfection (p.i.). Kinetic studies showed that the inflammatory infiltrate was dominated by the presence of alphabetaT CD3(+ )CD4(+ )CD8(-), alphabetaT CD3(+ )CD4(-)CD8(+ )lymphocytes and macrophages. The mRNA expression of the monokines IL-1beta and IL-12(p40) was elevated at 15 days p.i. and controlled at later time points. In contrast, TNF-alpha mRNA was expressed throughout the infection. Interestingly, we found that at 15 and 30 days p.i. cytokine expression was dominated by the presence of IFN-gamma mRNA, whereas at 60 days or later time points the balance of type 1 and type 2 cytokines was switched in favor of IL-4 and IL-10 mRNAs. The chemokine mRNAs encoding JE, MIP-1alpha, MIP-1beta, KC, and MIP-2 were all mainly expressed at 15 and/or 30 days p.i. and diminished thereafter. In contrast, the expression of RANTES, MIG and IP-10 mRNAs was augmented at 15 days p.i. and persisted at high levels up to 120 days p.i. Taken together, our results indicate that regulation of IFN-gamma and chemokine expression, associated with decreased tissue parasitism, may be largely responsible for the control of inflammation and immunopathology observed in the cardiac tissue of animals infected with T. cruzi.

Nitric oxide is involved in the lesions of the peripheral autonomic neurons observed in the acute phase of experimental Trypanosoma cruzi infection

Our aim was to investigate the possible involvement of nitric oxide (NO) in peripheral denervation during the acute phase of murine experimental Trypanosoma cruzi infection. Wistar male rats were infected with the Y strain of T. cruzi. One group of animals was also treated with the NO synthase inhibitor N-nitro-l-arginine. A group of uninfected animals was the control. At the 18th day of infection the animals were sacrificed. Quantification of neurons in the colon and heart and tissue parasitism in the heart was performed. Serum concentration of nitrate was measured and a histochemical technique for assessing NADPH-diaphorase activity in the colon was also performed. The infected animals presented a statistically significant decrease in the number of peripheral neurons in the colon and heart and a 2-fold increase in serum NO(3) concentration compared with controls. The animals treated with N-nitro-l-arginine showed almost an absence of NO(3) concentration in the serum and did not show loss of neurons compared with controls. These treated animals displayed a 15-fold increase in tissue parasitism compared with nontreated infected animals. The NADPH-diaphorase activity was much more intense in the muscle layers of the colon of the infected animals than in those of the controls. Taken together, these data suggest that NO is involved in the peripheral denervation observed in the acute phase of experimental T. cruzi infection.

beta-Chemokines enhance parasite uptake and promote nitric oxide-dependent microbiostatic activity in murine inflammatory macrophages infected with Trypanosoma cruzi

In the present study, we describe the ability of Trypanosoma cruzi trypomastigotes to stimulate the synthesis of beta-chemokines by macrophages. In vivo infection with T. cruzi led to MIP-1alpha, RANTES, and JE/MCP1 mRNA expression by cells from peritoneal inflammatory exudate. In addition, in vitro infection with T. cruzi resulted in expression of beta-chemokine MIP-1alpha, MIP-1beta, RANTES, and JE mRNA by macrophages. The expression of the beta-chemokine MIP-1alpha, MIP-1beta, RANTES, and JE proteins by murine macrophages cultured with trypomastigote forms of T. cruzi was confirmed by immunocytochemistry. Interestingly, macrophage infection with T. cruzi also resulted in NO production, which we found to be mediated mainly by beta-chemokines. Hence, treatment with anti-beta-chemokine-specific neutralizing antibodies partially inhibited NO release by macrophages incubated with T. cruzi parasites. Further, the addition of the exogenous beta-chemokines MIP-1alpha, MIP-1beta, RANTES, and JE/MCP-1 induced an increased T. cruzi uptake, leading to enhanced NO production and control of parasite replication in a dose-dependent manner. L-NMMA, a specific inhibitor of the L-arginine-NO pathway, caused a decrease in NO production and parasite killing when added to cultures of macrophages stimulated with beta-chemokines. Among the beta-chemokines tested, JE was more potent in inhibiting parasite growth, although it was much less efficient than gamma interferon (IFN-gamma). Nevertheless, JE potentiates parasite killing by macrophages incubated with low doses of IFN-gamma. Together, these results suggest that in addition to their chemotactic activity, murine beta-chemokines may also contribute to enhancing parasite uptake and promoting control of parasite replication in macrophages and may play a role in resistance to T. cruzi infection.

Gamma interferon modulates CD95 (Fas) and CD95 ligand (Fas-L) expression and nitric oxide-induced apoptosis during the acute phase of Trypanosoma cruzi infection: a possible role in immune response control

We have previously shown that splenocytes from mice acutely infected with Trypanosoma cruzi exhibit high levels of nitric oxide (NO)-mediated apoptosis. In the present study, we used the gamma interferon (IFN-gamma)-knockout (IFN-gamma(-/-)) mice to investigate the role of IFN-gamma in modulating apoptosis induction and host protection during T. cruzi infection in mice. IFN-gamma(-/-) mice were highly susceptible to infection and exhibited significant reduction of NO production and apoptosis levels in splenocytes but normal lymphoproliferative response compared to the infected wild-type (WT) mice. Furthermore, IFN-gamma modulates an enhancement of Fas and Fas-L expression after infection, since the infected IFN-gamma(-/-) mice showed significantly lower levels of Fas and Fas-L expression. The addition of recombinant murine IFN-gamma to spleen cells cultures from infected IFN-gamma(-/-) mice increased apoptosis levels, Fas expression, and NO production. In the presence of IFN-gamma and absence of NO, although Fas expression was maintained, apoptosis levels were significantly reduced but still higher than those found in splenocytes from uninfected mice, suggesting that Fas-Fas-L interaction could also play a role in apoptosis induction in T. cruzi-infected mice. Moreover, in vivo, the treatment of infected WT mice with the inducible nitric oxide synthase inhibitor aminoguanidine also led to decreased NO and apoptosis levels but not Fas expression, suggesting that IFN-gamma modulates apoptosis induction by two independent and distinct mechanisms: induction of NO production and of Fas and Fas-L expression. We suggest that besides being of crucial importance in mediating resistance to experimental T. cruzi infection, IFN-gamma could participate in the immune response control through apoptosis modulation.

The adjuvant effect of jacalin on the mouse humoral immune response to trinitrophenyl and Trypanosoma cruzi

We have evaluated the adjuvant action of jacalin, a lectin obtained from seeds of Artocarpus integrifolia, on humoral immune response against the trinitrophenyl (TNP) hapten when conjugated to it and to Trypanosoma cruzi. The protective effect of parasite-specific antibodies generated in mice immunized with epimastigote forms of T. cruzi plus jacalin was also evaluated by determining the parasitemia levels of animals after infection with 1000 trypomastigote forms. Immunization of mice with trinitrophenylated jacalin (TNP-JAC) in saline resulted in an antibody response to the TNP hapten that was eight and 16 times higher than that found in mice immunized with TNP-human gamma globulin (TNP-HGG) or TNP-bovine serum albumin (TNP-BSA), respectively. In addition, immunization with either a lysate or viable epimastigote forms of T. cruzi in the presence of jacalin resulted in a marked increase in the levels of anti-T. cruzi antibodies. The protective action of antibodies against acute infection by T. cruzi was evident when mice were immunized with 1.0 x 10(5) epimastigotes plus jacalin. These animals had a significantly lower parasitemia than those immunized with epimastigotes alone. In contrast, mice immunized with 1.0 x 10(6) epimastigotes developed very low levels of parasitemia, regardless of the presence of jacalin. These data suggest that jacalin is a potent adjuvant in the humoral response to TNP and T. cruzi, and that the protective action of the T. cruzi-specific antibodies depends on the number of parasites used in the immunization protocol.

Platelet-activating factor induces nitric oxide synthesis in Trypanosoma cruzi-infected macrophages and mediates resistance to parasite infection in mice

Trypanosoma cruzi replicates in nucleated cells and is susceptible to being killed by gamma interferon-activated macrophages through a mechanism dependent upon NO biosynthesis. In the present study, the role of platelet-activating factor (PAF) in the induction of NO synthesis and in the activation of the trypanocidal activity of macrophages was investigated. In vitro, PAF induced NO secretion by T. cruzi-infected macrophages and the secreted NO inhibited intracellular parasite growth. The addition of a PAF antagonist, WEB 2170, inhibited both NO biosynthesis and trypanocidal activity. The inducible NO synthase/L-arginine pathway mediated trypanocidal activity, since it was inhibited by treatment with L-N-monomethyl arginine (L-NMMA), an L-arginine analog. PAF-mediated NO production in infected macrophages appears to be dependent on tumor necrosis alpha (TNF-alpha) production, since the addition of a neutralizing anti-TNF-alpha monoclonal antibody mAb inhibited NO synthesis. To test the role of PAF in mediating resistance or susceptibility to T. cruzi infection, infected mice were treated with WEB 2170, a PAF antagonist. These animals had higher parasitemia and earlier mortality than did vehicle-treated mice. Taken together, our results suggest that PAF belongs to a group of mediators that coordinate the mechanisms of resistance to infections with intracellular parasites.

[Cerebral ischemic infarction in newborn infants. Diagnosis using pulsed and color Doppler imaging]

In newborn infant, cerebral infarction is often difficult to distinguish from cerebral hemorrhage, both pathologies being moreover frequently associated. We report a left anterior stroke in a fullterm newborn who had seizures on the third day of life. Ultrasound scanning showed a hyperechogenic zone in the territory of the left anterior cerebral artery. Pulsed and color Doppler imaging showed a decreased blood flow velocity in comparison to the opposite side, thus enabling the diagnosis.

Successive tick infestations selectively promote a T-helper 2 cytokine profile in mice

Several studies have revealed that T lymphocytes and cytokines play a crucial role in determining the outcome of parasitic infections in terms of protective immunity. In this study we found that Rhipicephalus sanguineus tick saliva stimulates transforming growth factor-beta (TGF-beta), and reduces interleukin-12 (IL-12) secretion by cells from normal C3H/HeJ mice. Moreover, murine lymph node cells harvested 6 days after the fourth infestation with ticks presented an 82.4% decrease in their proliferative response to concanavalin A (Con A) compared with the response of control cells. In addition, lymph node cells cultured in the presence of Con A showed a T-helper 2-type (Th2-type) cytokine profile, represented by augmented IL-4 and IL-10 and TGF-beta. On the other hand, the IL-2, interferon-gamma (IFN-gamma) and IL-12 synthesis was significantly inhibited. These results indicate that ticks may modulate the host's immune response through saliva injection. Considering that C3H/HeJ mice develop no protective immunity to R. sanguineus infestation, our results suggest that tick-induced Th2-type cytokines and a decreased proliferative response probably lead the host to a susceptible state to both tick and tick-transmitted pathogens.

Tool support for authoring eligibility criteria for cancer trials

A critical component of authoring new clinical trial protocols is assembling a set of eligibility criteria for patient enrollment. We found that clinical protocols in three different cancer domains can be categorized according to a set of clinical states that describe various clinical scenarios for that domain. Classifying protocols in this manner revealed similarities among the eligibility criteria and permitted some standardization of criteria based on clinical state. We have developed an eligibility criteria authoring tool which uses a standard set of eligibility criteria and a diagram of the clinical states to present the relevant eligibility criteria to the protocol author. We demonstrate our ideas with phase-3 protocols from breast cancer, prostate cancer, and non-small cell lung cancer. Based on measurements of redundancy and percentage coverage of criteria included in our tool, we conclude that our model reduces redundancy in the number of criteria needed to author multiple protocols, and it allows some eligibility criteria to be authored automatically based on the clinical state of interest for a protocol.

Nitric oxide-induced apoptotic cell death in the acute phase of Trypanosoma cruzi infection in mice

Production of gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) in Trypanosoma cruzi-infected mice results in the activation of inducible nitric oxide synthase (iNOS) and in elevated nitric oxide (NO) synthesis, which is important for the macrophage trypanocidal activity. However, NO has been shown to be involved in suppression of host immunity. In the present investigation, we studied the role of NO in inducing apoptosis in cells from BALB/c mice acutely infected by T. cruzi. Splenocytes from infected mice had a reduced cell viability and elevated levels of spontaneous apoptosis after 48 h in culture. Inhibition of NO production by the addition of the L-arginine analog NG-monomethyl-L-arginine (L-NMMA), or of monoclonal antibodies (mAbs) to IFN-gamma or TNF-alpha spleen cells, partially restored cell viability and caused a decrease in the levels of apoptosis in splenocytes from infected animals. Spleen cells from T. cruzi-infected mice had an apoptosis-specific pattern of internucleosomal DNA fragmentation which was most marked at the ninth day after infection when the plasma NO levels and parasitemia were increased. Treatment of infected mice with L-NMMA, anti-TNF-alpha, or anti-IFN-gamma mAbs caused reduction of both NO production and the amount of apoptotic cells, suggesting that NO plays a direct role in the induction of apoptosis in vivo. Taken together, these data support the hypothesis that, as well as modulating immunosuppression, NO produced by IFN-gamma and TNF-alpha activated macrophages plays a role in apoptosis induction during the acute phase of experimental T. cruzi infection.

Saliva of Rhipicephalus sanguineus tick impairs T cell proliferation and IFN-gamma-induced macrophage microbicidal activity

In this study, we investigated tick saliva effects on T cell proliferation, antigen presentation and IFN-gamma-induced macrophage activation, events which are associated with host immune defense mechanisms. Mice repeatedly infested with Rhipicephalus sanguineus ticks, similarly to dogs, did not develop resistance to further infestations. We determined that R. sanguineus tick saliva inhibited, in a dose-dependent manner, both Con-A and specific antigen-induced splenic T cell proliferation. Tick saliva diluted twenty times (64 microg/ml) inhibited Con-A-induced and antigen-specific T cell proliferation in 83% and 69%, respectively. In addition, the inhibition of cell proliferation correlated with a decrease in IL-2 production. Microconcentrator fractionated saliva was tested on a Con-A-induced cell proliferation assay, and showed that one fraction between 3 and 10 kDa and another smaller than 3 kDa can be responsible for the inhibition of T cell proliferation. Although saliva inhibited cell proliferation, it did not impair antigen presentation. Tick saliva further abrogated the killing of intracellular forms of Trypanosoma cruzi by IFN-gamma-activated macrophages. Moreover, saliva-induced macrophage inhibition of IFN-gamma-induced-trypanocidal activity was paralleled with 69% less nitric oxide (NO) production. Finally, tick saliva doubled the production of IL-10 and reduced 84.6% production of IFN-gamma by splenocytes cultured with T. cruzi, suggesting that decreased macrophage NO production may be due to a saliva-induced cytokine imbalance, leading to decreased NO synthase activity. Together, these data indicate that tick saliva can modulate host immune response, thus, contributing to its feeding success and favoring the transmission of tick-borne pathogens.

A morphometric study of maternal smoking on apoptosis in the syncytiotrophoblast

OBJECTIVES

To study syncytiotrophoblast apoptosis in the placenta of smoking and non-smoking pregnant women.

METHODS

Twelve neonates, pregnancies and placentas were available for study. Eight mothers smoked during pregnancy and the remaining four were non-smokers used as control subjects. The main outcome measure was the apoptotic syncytiotrophoblast index for each group. Apoptosis was detected by immunohistochemistry using the TUNEL method and quantitatively measured using a Merz grid. The apoptotic syncytiotrophoblast index was calculated as the ratio of mean apoptotic labeling to percent terminal villus area using high-power field microscopy.

RESULTS

Significant differences in apoptotic syncytiotrophoblast index were observed between the control group (15.06+/-3.72) and the smoker group (1.66+/-1.74) (P < 0.0001, Mann-Whitney test), but no differences were detected in clinical or morphometric data between groups.

CONCLUSIONS

The human placental syncytiotrophoblast undergoes apoptosis and this process is associated with inhibition of apoptosis by the smoking habit. The same way as the presence of trophoblast apoptosis is associated with modifications of the maternal-fetal exchange, the inhibitory effect of the smoking habit on syncytiotrophoblast could be responsible for the poor prognosis of pregnancy in the presence of maternal smoking.