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PubMed1991

Triggering of the vascular permeability reaction by activation of the Hageman factor-prekallikrein system by house dust mite proteinase.

A 30-kilodalton (kDa) proteinase from the house dust mite Dermatophagoides farinae (Df-proteinase) was recently purified (Takahashi et al. (1990) Int. Arch. Allergy Appl. Immunol. 91, 80-85). In this paper we detailed the biological activities of the Df-proteinase. The activation of the kinin cascade by Df-proteinase was examined in vitro by using purified guinea pig Hageman factor (HF), prekallikrein (PK) and high-molecular-weight kininogen (HMWK) and the effect of this proteinase on endogenous human plasma proteinase inhibitors (serpins) and alpha 2-macroglobulin was tested. In addition, enhancement of the vascular permeability reaction in guinea pig skin by Df-proteinase was examined in vivo. These experiments showed that Df-proteinase could activate all the steps of the kinin-generating cascade, i.e., HF, PK and HMWK, and that Df-proteinase retained proteolytic activity even in the presence of an excess amount of endogenous proteinase inhibitors in plasma. We also found that the marked enhancement of the vascular permeability reaction was induced by Df-proteinase via the activation of the kinin-generating cascade without the release of histamine. From these results, we conclude that the proteinase of the house dust mite, Df-proteinase, has the potential to generate bradykinin and that the presence of this proteinase in biological systems would exacerbate inflammatory reactions in some pathological conditions.

Animals↗
PubMed2004

Neuroprotection against ischemic/hypoxic brain damage: blockers of ionotropic glutamate receptor and voltage sensitive calcium channels.

The growing number of cellular and molecular pathways believed to be involved in mechanisms of ischemic cell death in the brain has spurred a similar growth in the number of potential neuroprotective modalities, the majority of which are pharmacological in nature. Preventing or minimizing the first few steps in the cascade of events leading to ischemic cell death would have a more profound effect on the postischemic outcome than intervention at later steps in that cascade. This logic is, of course, at the heart of the urgency in providing the stroke or cardiac arrest patient with the earliest possible neuroprotective treatment. For the purpose of assessing potential neuroprotective modalities, the use of a well-established cerebral hypoxic/ischemic model system is a prerequisite. In our studies, we have used two major approaches, in vitro and in vivo. We evaluated both agonists and antagonists of ionotropic glutamate receptor channels (IGRC) and their effects in exacerbating and attenuating, respectively, the posthypoxic/ischemic outcome. Other drugs were tested for their ability to block the L-type voltage-sensitive calcium channels (VSCC), which are responsible for calcium influx and overload upon hypoxia/ischemia. These two membrane protein entities, the IGRC and the VSCC, are believed to be involved in the early stages of the cellular cascade that leads to the demise of neurons posthypoxia/ischemia. Some of the drugs were also tested for possible interaction with each other searching for possible synergy. These and other published studies in the field are reviewed here.

Animals↗
PubMed2000

Protein kinase A mediates the modulation of the slow Ca(2+)-dependent K(+) current, I(sAHP), by the neuropeptides CRF, VIP, and CGRP in hippocampal pyramidal neurons.

We have studied modulation of the slow Ca(2+)-activated K(+) current (I(sAHP)) in CA1 hippocampal pyramidal neurons by three peptide transmitters: corticotropin releasing factor (CRF, also called corticotropin releasing hormone, CRH), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP). These peptides are known to be expressed in interneurons. Using whole cell voltage clamp in hippocampal slices from young rats, in the presence of tetrodotoxin (TTX, 0.5 microM) and tetraethylammonium (TEA, 5 mM), I(sAHP) was measured after a brief depolarizing voltage step eliciting inward Ca(2+) current. Each of the peptides CRF (100-250 nM), VIP (400 nM), and CGRP (1 microM) significantly reduced the amplitude of I(sAHP). Thus the I(sAHP) amplitude was reduced to 22% by 100 nM CRF, to 17% by 250 nM CRF, to 22% by 400 nM VIP, and to 40% by 1 microM CGRP. We found no consistent concomitant changes in the Ca(2+) current or in the time course of I(sAHP) for any of the three peptides, suggesting that the suppression of I(sAHP) was not secondary to a general suppression of Ca(2+) channel activity. Because each of these peptides is known to activate the cyclic AMP (cAMP) cascade in various cell types, and I(sAHP) is known to be suppressed by cAMP via the cAMP-dependent protein kinase (PKA), we tested whether the effects on I(sAHP) by CRF, VIP, and CGRP are mediated by PKA. Intracellular application of the PKA-inhibitor Rp-cAMPS significantly reduced the suppression of I(sAHP) by CRF, VIP, and CGRP. Thus with 1 mM Rp-cAMPS in the recording pipette, the average suppression of I(sAHP) was reduced from 78 to 26% for 100 nM CRF, from 83 to 32% for 250 nM CRF, from 78 to 30% for 400 nM VIP, and from 60 to 7% for 1 microM CGRP. We conclude that CRF, VIP, and CGRP suppress the slow Ca(2+)-activated K(+) current, I(sAHP), in CA1 hippocampal pyramidal neurons by activating the cAMP-dependent protein kinase, PKA. Together with the monoamine transmitters norepinephrine, serotonin, histamine, and dopamine, these peptide transmitters all converge on the cAMP cascade modulating I(sAHP).

Animals↗
PubMed2005

The role of Akt and mitogen-activated protein kinase systems in the protective effect of poly(ADP-ribose) polymerase inhibition in Langendorff perfused and in isoproterenol-damaged rat hearts.

Blocking poly(ADP-ribosyl)ation of nuclear proteins protects the heart from ischemia-reperfusion injury. In addition, activation of Akt and mitogen-activated protein kinase (MAPK) cascades also plays a pivotal role in the survival of cardiomyocytes during ischemia-reperfusion; however, the potential interplay between these pathways is yet to be elucidated. We therefore tested the hypothesis whether poly(ADP-ribose) polymerase (PARP) inhibition can modulate Akt and MAPK signaling of ischemic-reperfused rat hearts. A novel PARP inhibitor, L-2286 [2-[(2-piperidin-1-yletil)thio]quinazolin-4(3H)-one] was administered during ischemia-reperfusion in Langendorff perfused rat hearts and in isoproterenol-induced myocardial infarction. Thereafter, the cardiac energy metabolism, oxidative damage, and the phosphorylation state of Akt and MAPK cascades were monitored. L-2286 exerted significant protective effect against ischemia-reperfusion-induced myocardial injury in both experimental models. More importantly, L-2286 facilitated the ischemia-reperfusion-induced activation of Akt, extracellular signal-regulated kinase, and p38-MAPK in both isolated hearts and in vivo cardiac injury. By contrast, isoproterenol-induced rapid c-Jun N-termainal kinase activation was repressed by L-2286. Here, we provide evidence for the first time that PARP inhibition beneficially modulates the cardiac Akt and MAPK signaling in ex vivo and in vivo ischemia-reperfusion models. We therefore propose that this novel mechanism may contribute to the cardioprotective properties of PARP inhibitors.

Animals↗
PubMed2000

Changes in the uptake of antiretroviral therapy and survival in people with known duration of HIV infection in Europe: results from CASCADE.

OBJECTIVES: To estimate the times from HIV seroconversion to death, and to the initiation of therapy and the mean CD4 cell count at initiation. DESIGN AND METHODS: Using Kaplan-Meier methods, allowing for late entry, we analysed CASCADE (Concerted Action on SeroConversion to AIDS and Death in Europe) data from HIV-infected individuals with known dates of seroconversion. We tested the association of time to initiation of therapy and of survival with: exposure category, age, sex, presentation during acute infection and calendar year at risk (as time-dependent) in Cox proportional hazards models, stratifying by study. We estimated the mean CD4 cell count at the initiation of therapy using interval regression. RESULTS: Of 5893 seroconverters, 1613 (27.4%) died. The risk of death was 65% lower (95% CI = 57-72%) in 1997-99 compared to previous years. Being at risk in earlier calendar years, older age and a short interval between negative and positive test dates were associated with shorter survival. At the same time from seroconversion, people at risk in 1997-99, older individuals and people with a short test interval were more likely to initiate therapy. Injecting drug users (IDUs) were less likely to initiate therapy compared to those exposed through sex between men (RR = 0.79, 95% CI = 0.69-0.89). The mean CD4 cell count at therapy initiation was 205 cells/mL, which increased significantly over time. Although the earlier initiation of therapy was consistent with longer survival in the 1997-99 period, we found no evidence of this in other calendar periods. CONCLUSIONS: We found a significant and substantial reduction in the risk of death and a significant trend of earlier initiation of antiretroviral therapy (ART) in the 1997-99 period. Although IDUs were less likely to initiate therapy their overall survival did not appear to differ from others. The increasing tendency to initiate ART closer to seroconversion has unknown long-term consequences which require monitoring.

Adolescent↗
PubMed2000

Multi-element analysis by inductively coupled plasma optical emission spectrometry of airborne particulate matter collected with a low-pressure cascade impactor.

A method was developed for the elemental analysis of size segregated particles ranging from 0.03 to 10 microns. Sampling and analysis problems are discussed in this paper. Particles were collected with a Dekati low-pressure cascade impactor. PTFE filters coated with oleic acid were used as substrate. Particles were microwave digested in closed vessels. The optimum digestion mixture was composed of HNO3 (1 mL), HF (50 microL) and H2O (1 mL). The optimal power setting and digestion time were studied in order to achieve an efficient digestion. A ca. 35 min microwave digestion cycle at a 650 W maximum power allowed complete digestion of the samples. Special emphasis was placed on the pressure in the closed vessels to avoid sample losses. Solution samples were analysed by inductively coupled plasma optical emission spectrometry using an ultrasonic nebuliser for 18 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Sr, Ti, V, Zn). This procedure was tested with NIST Standard Reference Material 1648 Urban Particulate. Recoveries for certified elements ranged from 95 to 105% except for Al (90%). The influence of cascade impactor materials was investigated with 44 field samples. Strong artefacts due to contamination were shown for analysis at environmental concentrations of Al, Cr, Mn and Ni.

Air Pollutants↗
PubMed1995

Tissue factor promotes melanoma metastasis by a pathway independent of blood coagulation.

Several studies have established a link between blood coagulation and cancer, and more specifically between tissue factor (TF), a transmembrane protein involved in initiating blood coagulation, and tumor metastasis. In the study reported here, a murine model of human melanoma metastasis was used for two experiments. (i) The first experiment was designed to test the effect of varying the level of TF expression in human melanoma cells on their metastatic potential. Two matched sets of cloned human melanoma lines, one expressing a high level and the other a low level of the normal human TF molecule, were generated by retroviral-mediated transfections of a nonmetastatic parental line. The metastatic potential of the two sets of transfected lines was compared by injecting the tumor cells into the tail vein of severe combined immunodeficiency (SCID) mice and later examining the lungs and other tissues for tumor development. Metastatic tumors were detected in 86% of the mice injected with the high-TF lines and in 5% of the mice injected with the low-TF lines, indicating that a high TF level promotes metastasis of human melanoma in the SCID mouse model. This TF effect on metastasis occurs with i.v.-injected melanoma cells but does not occur with primary tumors formed from s.c.-injected melanoma cells, suggesting that TF acts at a late stage of metastasis, after tumor cells have escaped from the primary site and entered the blood. (ii) The second experiment was designed to analyze the mechanism by which TF promotes melanoma metastasis. The procedure involved testing the effect on metastasis of mutations in either the extracellular or cytoplasmic domains of the transmembrane TF molecule. The extracellular mutations introduced two amino acid substitutions that inhibited initiation by TF of the blood-coagulation cascade; the cytoplasmic mutation deleted most of the cytoplasmic domain without impairing the coagulation function of TF. Several human melanoma lines expressing high levels of either of the two mutant TF molecules were generated by retroviral-mediated transfection of the corresponding TF cDNA into the nonmetastatic parental melanoma line, and the metastatic potential of each transfected line was tested in the SCID mouse model. Metastases occurred in most mice injected with the melanoma lines expressing the extracellular TF mutant but were not detected in most mice injected with the melanoma lines expressing the cytoplasmic TF mutant. Results with the extracellular TF mutant indicate that the metastatic effect of TF in the SCID mouse model does not involve products of the coagulation cascade. Results with the cytoplasmic TF mutant indicate that the cytoplasmic domain of TF is important for the metastatic effect, suggesting that the TF could transduce a melanoma cell signal that promotes metastasis.

Animals↗
PubMed1996

Complement activation by C-reactive protein on the HEp-2 cell substrate.

The complement (C) activation by C-reactive protein (CRP) in acute-phase sera is routinely tested in our laboratory by means of an indirect immunofluorescence method (C3-IFT) on rat kidney sections. This C3-IFT assay is based on the binding of CRP to the renal tissue followed by the fixation of C4 and C3 components to distinct vessel-associated medullary structures as a result of CRP-mediated C activation in vitro. While the activation cascade leading to the deposition of C4 and C3 could previously be deduced experimentally, we were unable as yet to visualize CRP and the components of the C1 complex on kidney sections when testing patients' sera by indirect immunofluorescence. In an attempt to analyze the mechanisms of unexpectedly negative C3-IFT results (e.g. bacterial endocarditis) we employed monolayers of fixed HEp-2 cells which have previously been shown to be a suitable substrate for CRP binding. By incubating purified native CRP supplemented with normal human serum as a source of C we detected the C components Clq, Clr, Cls, C4 and C3 in the same speckled immunofluorescent pattern on HEp-2 cell nuclei as described characteristically for CRP binding. The serial activation steps from CRP up to C3 could also be followed on HEp-2 cells using C3-IFT-positive acute-phase sera. However, certain C3-IFT-negative acute-phase sera showed an arrest between Cls and C4 of the CRP-mediated C activation cascade. HEp-2 cells can thus be used to monitor the process of autologous C activation initiated by endogeneous CRP in patients' sera. In contrast to native CRP, urea-modified CRP (mCRP) did not bind to HEp-2 cell nuclei, but was detected in association with distinct filamentous cytoplasmic structures. Unlike its native counterpart, binding of mCRP was not followed by a deposition of C components.

Animals↗
PubMed1997

Prevention and suppression of autoimmune encephalomyelitis by EUK-8, a synthetic catalytic scavenger of oxygen-reactive metabolites.

Breakdown of T cell tolerance to self-myelin basic protein induces an autoimmune process that leads to demyelination of the central nervous system (CNS) in multiple sclerosis (MS) patients. While the autoimmune disease is initiated by antigen-specific autoreactive T cells, there is accumulating evidence that CNS injury is essentially mediated by CNS-infiltrating inflammatory cells. In addition, it is established that activated macrophages and polymorphonuclear cells contribute to tissue damage in several inflammatory diseases by releasing highly reactive oxygen metabolites. It was therefore possible that demyelination associated with MS results from oxidative injury caused by a cascade of oxygen reactive metabolites produced by CNS-infiltrating activated macrophages and other inflammatory cells. To address this question, we tested the effect of a synthetic catalytic scavenger of oxygen radicals, EUK-8, on experimental allergic encephalomyelitis (EAE) in mice, the animal model for MS in humans. We observed that repeated injection of EUK-8 starting at the time of EAE induction delayed the onset and markedly reduced the severity of the disease. Strikingly, all EUK-8-treated mice completely recovered after 40 days. In addition, we showed that posttreatment with EUK-8 4 days after EAE induction also resulted in a significant amelioration of EAE disease. These results indicate that oxygen metabolites secreted by inflammatory cells at the site of tissue destruction play a major role in the induction and presumably the perpetuation of the autoimmune disease. This study also suggests that treatment with oxygen metabolites scavengers may represent a novel and promising strategy to prevent the onset and to block the course of ongoing autoimmune encephalomyelitis and other inflammatory autoimmune diseases.

Animals↗
PubMed1990

Leukocyte inhibitory factor activates human neutrophils and macrophages to release leukotriene B4 and thromboxanes.

Recent evidence has proved that cytokines can stimulate the production of 5-lipoxygenase products. Leukotriene B4 (LTB4) is a major mediator of leukocyte activation in acute inflammatory reactions, which produce chemotaxis, lysosomal enzyme release, and cell aggregation. Leukocyte inhibitory factor (LIF) also causes biological responses related to inflammation, i.e., LIF directly induces specific granule secretion by polymorphonuclears (PMNs) and potentiates many formyl-methionyl-leucyl-phenylalanine (FMLPs) mediated responses. Since arachidonic acid products are important mediators of inflammation, we have studied the effects of LIF on the arachidonic acid cascade products LTB4 and thromboxane A2 (TxA2). Resuspended at a final concentration of greater than 95% polymorphonuclear PMNs were isolated and tested with some cytokines on the release of LTB4 and TxA2. Peripheral blood mononuclear cells were isolated and seeded in Petri dishes and incubated for 60 min. Adherent macrophages were used for the cytokine stimulation study. Both types of leukocytes were treated with LIF, interleukin 6 (IL 6), and granulocyte-monocyte colony stimulating factor (GM-CSF) at different concentrations, and test agents A23187 and FMLP. Radioimmunoassay for LTB4 and TxB2 was determined by the resulting supernatants. Treatment of PMNs and macrophages with LIF at different concentrations proved to generate significant increases in LTB4 and TxA2 production. This was compared with IL 6 and GM-CSF, which had no effects. In these experiments, TxA2 generations could not be attributed to platelet contamination of PMN suspensions. The quantity of platelet contamination was not sufficient to influence how much TxB2 was produced. The similarities of LIF to other arachidonate stimulating cytokines suggest a similar mode of action in producing hematologic changes typical of tissue injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcimycin↗
PubMed2002

Regulation of IL-13 synthesis in human lymphocytes: implications for asthma therapy.

1. IL-13 is an important mediator in inflammatory diseases such as asthma. IL-13 is mainly produced by T cells. However, signalling pathways leading to induction of this cytokine are not well-characterized. We analysed the regulation of IL-13 in human peripheral blood mononuclear cells and CD4(+) T cells. 2. Cyclosporine (CsA) and FK-506 inhibited IL-13 synthesis, when cells were stimulated by TPA/ionomycin. However, stimulation by alpha-CD3/alpha-CD28 led to an enhanced IL-13 synthesis. 3. NF-kappa B inhibitor N-tosyl-L-lysine chloromethylketone (TLCK) inhibited IL-13 synthesis more effectively after TPA/ionomycin stimulation. After alpha-CD3/alpha-CD28 stimulation, only 300 microM TLCK inhibited IL-13 synthesis. Dexamethasone inhibited IL-13 equally effective after alpha-CD3/alpha-CD28 and TPA/ionomycin stimulation. 4. p38 MAPK inhibitor SB203580 inhibited IL-13 synthesis only partially. MEK inhibitor U0126 inhibited TPA/ionomycin induced IL-13 synthesis very effectively, whereas alpha-CD3/alpha-CD28 stimulated IL-13 induction was resistant to this drug. 5. These results were confirmed in purified CD4(+) T cells. In difference to PBMCs alpha-CD3/alpha-CD28 stimulated IL-13 synthesis was effectively inhibited by CsA, FK-506 and U0126. 6. Therefore U0126 was tested in an animal model of allergic asthma. We could demonstrate for the first time that inhibition of the MEK - ERK cascade is a therapeutic option for asthma. Intraperitoneal administration of 10 mg kg(-1) U0126 reduced lung eosinophilia in ovalbumin-challenged Brown Norway rats by 44%. 7. These results demonstrate that different signalling pathways are involved in regulating IL-13 synthesis in primary human T cells. Characterizing highly potent inhibitors of IL-13 synthesis can be exploited to identify new drugs to treat immunological diseases such as asthma.

Animals↗
PubMed1999

A mitogen-activated protein kinase of the corn leaf pathogen Cochliobolus heterostrophus is involved in conidiation, appressorium formation, and pathogenicity: diverse roles for mitogen-activated protein kinase homologs in foliar pathogens.

Fungal pathogens perceive and respond to molecules from the plant, triggering pathogenic development. Transduction of these signals may use heterotrimeric G proteins, and it is thought that protein phosphorylation cascades are also important. We have isolated a mitogen-activated protein kinase homolog from the corn pathogen Cochliobolus heterostrophus to test its role as a component of the transduction pathways. The new gene, CHK1, has a deduced amino acid sequence 90% identical to Pmk1 of the rice blast fungus Magnaporthe grisea and 59% identical to Fus3 of Saccharomyces cerevisiae. A series of chk1 deletion mutants has poorly developed aerial hyphae, autolysis, and no conidia. No pseudothecia are formed when a cross between two Deltachk1 mutants is attempted. The ability of Deltachk1 mutants to infect corn plants is reduced severely. The growth pattern of hyphae on a glass surface is strikingly altered from that of the wild type, forming coils or loops, but no appressoria. This set of phenotypes overlaps only partially with that of pmk1 mutants, the homologous gene of the rice blast fungus. In particular, sexual and asexual sporulation both require Chk1 function in Cochliobolus heterostrophus, in contrast to Pmk1, but perhaps more similar to yeast, where Fus3 transmits the mating signal. Chk1 is required for efficient colonization of leaf tissue, which can be compared with filamentous invasive growth of yeast, modulated through another closely related mitogen-activated protein kinase, Kss1. Ubiquitous signaling elements thus are used in diverse ways in different plant pathogens, perhaps the result of coevolution of the transducers and their targets.

Amino Acid Sequence↗
PubMed2003

An ENSEMBLE machine learning approach for the prediction of all-alpha membrane proteins.

MOTIVATION: All-alpha membrane proteins constitute a functionally relevant subset of the whole proteome. Their content ranges from about 10 to 30% of the cell proteins, based on sequence comparison and specific predictive methods. Due to the paucity of membrane proteins solved with atomic resolution, the training/testing sets of predictive methods for protein topography and topology routinely include very few well-solved structures mixed with a hundred proteins known with low resolution. Moreover, available predictors fail in predicting recently crystallised membrane proteins (Chen et al., 2002). Presently the number of well-solved membrane proteins comprises some 59 chains of low sequence homology. It is therefore possible to train/test predictors only with the set of proteins known with atomic resolution and evaluate more thoroughly the performance of different methods. RESULTS: We implement a cascade-neural network (NN), two different hidden Markov models (HMM), and their ensemble (ENSEMBLE) as a new method. We train and test in cross validation the three methods and ENSEMBLE on the 59 well resolved membrane proteins. ENSEMBLE scores with a per-protein accuracy of 90% for topography and 71% for topology, outperforming the best single method of 7 and 5 percentage points, respectively. When tested on a low resolution set of 151 proteins, with no homology with the 59 proteins, the per-protein accuracy of ENSEMBLE is 76% for topography and 68% for topology. Our results also indicate that the performance of ENSEMBLE is higher than that of the best predictors presently available on the Web.

Algorithms↗
PubMed2006

Plasmodium falciparum-infected erythrocytes induce tissue factor expression in endothelial cells and support the assembly of multimolecular coagulation complexes.

BACKGROUND: Plasmodium falciparum malaria infects 300-500 million people every year, causing 1-2 million deaths annually. Evidence of a coagulation disorder, activation of endothelial cells (EC) and increase in inflammatory cytokines are often present in malaria. OBJECTIVES: We have asked whether interaction of parasitized red blood cells (pRBC) with EC induces tissue factor (TF) expression in vitro and in vivo. The role of phosphatidylserine-containing pRBC to support the assembly of blood coagulation complexes was also investigated. RESULTS: We demonstrate that mature forms of pRBC induce functional expression of TF by EC in vitro with productive assembly of the extrinsic Xnase complex and initiation of the coagulation cascade. Late-stage pRBC also support the prothrombinase and intrinsic Xnase complex formation in vitro, and may function as activated platelets in the amplification phase of the blood coagulation. Notably, post-mortem brain sections obtained from P. falciparum-infected children who died from cerebral malaria and other causes display a consistent staining for TF in the EC. CONCLUSIONS: These findings place TF expression by endothelium and the amplification of the coagulation cascade by pRBC and/or activated platelets as potentially critical steps in the pathogenesis of malaria. Furthermore, it may allow investigators to test other therapeutic alternatives targeting TF or modulators of EC function in the treatment of malaria and/or its complications.

Adolescent↗
PubMed2005

LPS-activated complement, not LPS per se, triggers the early release of PGE2 by Kupffer cells.

The intravenous injection of LPS rapidly evokes fever. We have hypothesized that its onset is mediated by prostaglandin (PG)E(2) quickly released by Kupffer cells (Kc). LPS, however, does not stimulate PGE(2) production by Kc as rapidly as it induces fever; but complement (C) activated by LPS could be the exciting agent. To test this hypothesis, we injected LPS (2 or 8 microg/kg) or cobra venom factor (CVF, an immediate activator of the C cascade that depletes its substrate, ultimately causing hypocomplementemia; 25 U/animal) into the portal vein of anesthetized guinea pigs and measured the appearance of PGE(2), TNF-alpha, IL-1beta, and IL-6 in the inferior vena cava (IVC) over the following 60 min. LPS (at both doses) and CVF induced similar rises in PGE(2) within the first 5 min after treatment; the rises in PGE(2) due to CVF returned to control in 15 min, whereas PGE(2) rises due to LPS increased further, then stabilized. LPS given 3 h after CVF to the same animals also elevated PGE(2), but after a 30- to 45-min delay. CVF per se did not alter basal PGE(2) and cytokine levels and their responses to LPS. These in vivo effects were substantiated by the in vitro responses of primary Kc from guinea pigs to C (0.116 U/ml) and LPS (200 ng/ml). These results indicate that LPS-activated C rather than LPS itself triggers the early release of PGE(2) by Kc.

Animals↗
PubMed2005

The IGF system: new developments relevant to pediatric practice.

In the 50 years since the initial report of the 'sulfation factor' or 'somatomedin'hypothesis, the IGF system has established itself as the primary mediator of both intrauterine and postnatal growth in mammals. IGF deficiency (IGFD) has emerged as an important clinical diagnosis: secondary IGFD results from insufficient production of GH and is characterized by postnatal growth failure; primary IGFD can result from abnormalities of the GH receptor or GH signaling cascade, or from mutations or deletions of the IGF-I gene. Monitoring IGF production during short-term IGF generation tests or during chronic GH therapy can provide a means for evaluating the efficacy and safety of GH treatment. IGF-I, either alone or in combination with IGF binding proteins, is the treatment of choice for primary IGFD and may have a role in treatment of idiopathic short stature when accompanied by decreased serum concentrations of IGF-I.

Child↗
PubMed2002

Antimetastatic drugs in prostate cancer.

Despite the benefits of local therapy with radical prostatectomy and radiation, many patients with prostate cancer require hormonal ablation. While chemotherapy has proven efficacy when the disease progresses to androgen-independent prostate cancer, patients ultimately succumb to the disease, thus the identification of other active therapies is needed. Future treatment modalities include molecular targeted therapies. Prostate cancer has been an ideal model to study the multiple steps required in the metastatic cascade. These steps have been utilized in the development of metastasis inhibitors. This review will present promising agents that have been tested preclinically or are undergoing clinical investigation for their abilities in preventing prostate cancer metastasis. Because prostate cancer metastasizes preferentially to the bone, special attention will be given to agents that interfere with this pattern of metastasis. Specifically, the efficacy of angiogenesis inhibitors, metalloproteinase inhibitors, inhibitors of prostate cancer cell- endothelial cell interactions, and bisphosphonates will be reported. In addition, the introduction of these novel agents has raised many questions as to the relevance and optimal utilization of current clinical trial designs. Issues regarding combination therapy with chemotherapy, optimal timing of treatment with metastatic inhibitors, and the need for surrogate endpoints for molecular targeted therapies will be discussed.

Angiogenesis Inhibitors↗
PubMedDate not supplied

[The molecular mechanisms of cerebral ischemia: the possible therapeutic interventions].

Therapeutic interventions for acute ischemic stroke have not yet been established in clinical practice. The recognition of an area of reduced blood flow in which neuronal death may be prevented has focused attention on treatments aiming at minimizing ischemic brain damage, if they are initiated within short time after occlusion. The combination of restoring blood flow and providing neuroprotection may be the most productive approach in human acute ischemic stroke, but this combined therapy requires testing through clinical trials. To gain insight into the molecular mechanisms of cerebral ischemia, this review examines the excito-toxic cascade, synthesis and role of nitric oxide and oxidants, gene regulation and possible neuroprotective therapeutic targets. As neuroprotectants, glutamate-antagonists, calcium-antagonists and free radical scavengers have been investigated. The role of nitric oxide is very complex, as it can be cytotoxic or cytoprotective in relation to sources, time of synthesis, and medium redox state. Animal gene studies suggest that nitric oxide produced by endothelial nitric oxide synthase may be advantageous, while nitric oxide produced by neuronal and inducible nitric oxide synthase disadvantageous. A treatment strategy could involve the use of selective inhibitors of different types of nitric oxide synthase. Cell death after cerebral ischemia occurs through the dual pathway of ischemic necrosis and apoptosis. Novel therapies may be directed at genes mediating either recovery or apoptosis. There are, as yet, no conclusive data concerning the safety and efficacy of neuroprotectants in humans. Differences between animal models and clinical conditions may justify the discrepancy between experimental data and clinical practice.

Animals↗