Triage body temperature and its influence on patients with acute myocardial infarction.

BACKGROUND: Fever can occur after acute myocardial infarction (MI). The influence of body temperature (BT) after hospital arrival on patients with acute MI has rarely been investigated. METHODS: Patients who were diagnosed with acute MI in the emergency department (ED) of a tertiary teaching hospital between 1 January 2020 and 31 December 2020 were enrolled. Based on the tympanic temperature obtained at the ED triage, patients were categorized into normothermic (35.5°C-37.5°C), hypothermic (< 35.5°C), or hyperthermic (> 37.5°C) groups. The primary outcome was in-hospital cardiac arrest (IHCA), while the secondary outcomes were adverse events. Statistical significance was set at p < 0.05. RESULTS: There were 440 enrollees; significant differences were found among the normothermic (n = 369, 83.9%), hypothermic (n = 27, 6.1%), and hyperthermic (n = 44, 10.0%) groups in the triage respiratory rate (median [IQR]) (20.0 [4.0] cycles/min versus 20.0 [4.0] versus 20.0 [7.5], p = 0.009), triage heart rate (88.0 [29.0] beats/min versus 82.0 [28.0] versus 102.5 [30.5], p < 0.001), presence of ST-elevation MI (42.0% versus 66.7% versus 31.8%, p = 0.014), need for cardiac catheterization (87.3% versus 85.2% versus 72.7%, p = 0.034), initial troponin T level (165.9 [565.2] ng/L versus 49.1 [202.0] versus 318.8 [2002.0], p = 0.002), peak troponin T level (343.8 [1405.9] ng/L versus 218.7 [2318.2] versus 832.0 [2640.8], p = 0.003), length of ICU stay (2.0 [3.0] days versus 3.0 [8.0] versus 3.0 [9.5], p = 0.006), length of hospital stay (4.0 [4.5] days versus 6.0 [15.0] versus 10.5 [10.8], p < 0.001), and infection during hospitalization (19.8% versus 29.6% versus 63.6%, p < 0.001) but not in IHCA (7.6% versus 14.8% versus 11.4%, p = 0.323) or any adverse events (50.9% versus 48.1% versus 63.6%, p = 0.258). Multivariable analysis showed no significant association of triage BT with IHCA or any major complication. CONCLUSION: Triage BT did not show a significant association with IHCA or adverse events in patients with acute MI. However, triage BT could be associated with different clinical presentations and should warrant further investigation.

Adequacy of care during interfacility transfer in Taiwan: A pilot study.

BACKGROUND/PURPOSE: Interfacility transfer (IFT) in Asian communities is seldom discussed. We aimed to describe the characteristics of IFT in Taiwan and to explore the adequacy of care during transfer. METHODS: A retrospective, cross-sectional, descriptive study was conducted using standardized, paper-based interfacility ambulance transfer records between 1 January 2018 and 31 January 2018 from Tainan City, Taiwan. The mode of patient care needed was classified as advanced life support (ALS) or basic life support (BLS) cares based on clinical conditions. ALS providers were defined as physicians and EMT-Paramedics, while BLS providers were defined as nurse practitioners, nurses, EMT-1s and EMT-2s. RESULTS: Of the 377 (227 [60.2%] were >65 years old; 219 [58.1%] were male) IFTs enrolled in the final analysis, 210 (55.7%) patients met the ALS transfer criteria, with poor consciousness (n = 158), tachypnea (n = 17), tachycardia (n = 5), bradycardia (n = 7), hypertension (n = 12), hypotension (n = 13), hypoxia (n = 4), endotracheal intubation (n = 18), a tracheostomy (n = 25), a precipitous labor (n = 1), and after resuscitation for out-of-hospital cardiac arrest (n = 10) or in-hospital cardiac arrest (n = 3). None of the patients who required ALS care had adequate ambulance staffing. Of the 167 BLS IFTs, 9 (5.4%) patients deteriorated and required ALS care during transportation, which included worsened consciousness (n = 2), tachycardia (n = 1), hypertension (n = 2), hypotension (n = 1), and hypoxia (n = 3). The rates of deterioration during BLS-transferals from the emergency departments, general wards, nursing facilities, and unknown areas were 4.8%, 4.7%, 7.7%, and 7.1%, respectively (p = 0.93). CONCLUSION: The patient care during IFT in Taiwan is inadequate currently and should warrant attention.

Predictive performances of ALS and BLS termination of resuscitation rules in out-of-hospital cardiac arrest for different resuscitation protocols.

BACKGROUND: Resuscitation guidance has advanced; however, the predictive performance of the termination of resuscitation (TOR) rule has not been validated for different resuscitation protocols published by the American Heart Association (AHA). METHODS: A retrospective study validating the basic life support (BLS) and advanced life support (ALS) TOR rules was conducted using an Utstein-style database in Tainan city, Taiwan. Adult patients with nontraumatic out-of-hospital cardiac arrests from January 1, 2015, to December 31, 2015, (using the AHA 2010 resuscitation protocol) and from January 1, 2020, to December 31, 2020, (using the AHA 2015 resuscitation protocol) were included. The characteristics of rule performance were calculated, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value. RESULTS: Among 1260 eligible OHCA patients in 2015, 757 met the BLS TOR rule and 124 met the ALS TOR rule. The specificity and PPV for predicting unfavorable neurological outcomes were 61.1% and 99.0%, respectively, for the BLS TOR rule and 93.8% and 99.2%, respectively, for the ALS TOR rule. A total of 970 OHCA patients were enrolled in 2020, of whom 438 met the BLS TOR rule and 104 met the ALS TOR rule. The specificity and PPV for predicting unfavorable neurological outcomes were 85.7% and 100%, respectively, for the BLS TOR rule and 99.5% and 100%, respectively, for the ALS TOR rule. CONCLUSIONS: Both the BLS and ALS TOR rules performed better when using the 2015 AHA resuscitation protocols compared to the 2010 protocols, with increased PPVs and decreased false-positive rates in predicting survival to discharge and good neurological outcomes at discharge. The BLS and ALS TOR rules can perform differently while the resuscitation protocols are updated. As the concepts and practices of resuscitation progress, the BLS and ALS TOR rules should be evaluated and validated accordingly.

Electrolyte abnormalities and laboratory findings in patients with out-of-hospital cardiac arrest who have kidney disease.

PURPOSES: Although electrolyte abnormalities have been generally considered the major cause of out-of-hospital cardiac arrest (OHCA) in patients with kidney disease (KD), this association has never been prospectively validated. METHODS: A prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2009. The study sample consisted of consecutively admitted patients with nontraumatic OHCA. Based on the estimated glomerular filtration rate (eGFR, unit: milliliters per minute per 1.73 m(2)), the enrollees were divided into 3 groups: group A (normal kidney function or mild KD; eGFR, 60.0), group B (moderate KD; eGFR between 15.0 and 59.9), and group C (severe KD; eGFR<15.0 or on dialysis). The laboratory findings of the groups were compared. Two-tailed P values less than .005 were considered significant. RESULTS: Two hundred thirty-four enrollees (137 were male) were divided into 3 groups: group A (n = 51; 21.8%), group B (n = 128; 54.7%), and group C (n = 55; 23.5%). Compared with the other 2 groups, group C presented significantly higher serum potassium and magnesium and lower pH and hemoglobin level (all P < .005). After stratifications of the significant variables, a post hoc analysis revealed that group C presented significantly higher incidences of hypermagnesemia (Mg >2.5 mmol/L) and severe hyperkalemia (K >6.5 mmol/L) (both P < .005) than the other 2 groups. The odds ratios of the incidence of severe hyperkalemia in group C was 3.37 (95% confidence intervals, 1.46-7.77) compared with group A (50.9% vs 23.5%, P < .005). CONCLUSIONS: Severe hyperkalemia is common in patients with OHCA who have severe KD and should be considered during resuscitation for these patients.

Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests.

PURPOSES: Outcome prediction for out-of-hospital cardiac arrest (OHCA) is of medical, ethical, and socioeconomic importance. We hypothesized that blood ammonia may reflect tissue hypoxia in OHCA patients and conducted this study to evaluate the prognostic value of ammonia for the return of spontaneous circulation (ROSC). METHODS: This prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2008. The subjects consisted of OHCA patients who were sent to the emergency department (ED). The primary outcome was ROSC. The prognostic values were calculated for ammonia levels and the partial pressure of ammonia (pNH(3)), and the results were depicted as a receiver operating characteristics curve with an area under the curve. RESULTS: Among 119 patients enrolled in this study, 28 patients (23.5%) achieved ROSC. Ammonia levels and pNH(3) in the non-ROSC group were significantly higher than those in the ROSC group (167.0 µmol/L vs 80.0 µmol/L, P < .05; 2.61 × 10(-5) vs 1.67 × 10(-5) mm Hg, P < .05, respectively). The predictive capacity of area under the curve for ammonia and pNH(3) for non-ROSC was 0.85 (95% confidence interval, 0.75-0.95) and 0.73 (95% confidence interval, 0.61-0.84), respectively. The multivariate analysis confirmed that ammonia and pNH(3) are independent predictors of non-ROSC. The prognostic value of ammonia was better than that of pNH(3). The cutoff level for ammonia of 84 µmol/L was 94.5% sensitive and 75.0% specific for predicting non-ROSC with a diagnostic accuracy of 89.9%. CONCLUSIONS: Hyperammonemia on ED arrival is independently predictive of non-ROSC for OHCA patients. The findings may offer useful information for clinical management.

Challenges of Using Instant Communication Technology in the Emergency Department during the COVID-19 Pandemic: A Focus Group Study.

A record outbreak of community-spread COVID-19 started on 10 May 2021, in Taiwan. In response to the COVID-19 pandemic, care facilities have adopted various protocols using instant communication technology (ICT) to provide remote yet timely healthcare while ensuring staff safety. The challenges of patient evaluation in the emergency department (ED) using ICT are seldom discussed in the literature. The objective of this study was to investigate the factors influencing the utility of ICT for patient assessment in emergency settings during the pandemic. The patient flow protocol and the ED layout were modified and regionalized into different areas according to the patient's risk of COVID-19 infection. Nine iPads were stationed in different zones to aid in virtual patient assessment and communication between medical personnel. A focus group study was performed to assess and analyze the utility of the ICT module in the ED. Eight emergency physicians participated in the study. Of them, four (50%) had been directly involved in the development of the ICT module in the study hospital. Three main themes that influenced the application of the ICT module were identified: setting, hardware, and software. The setting theme included six factors: patient evaluation, subspecialty consultation, patient privacy and comfortableness, sanitation, cost, and patient acceptability. The hardware theme included six factors: internet connection, power, quality of image and voice, public or personal mode, portable or fixed mode, and maintenance. The software theme included six factors: platform choices, security, ICT accounts, interview modes, video/voice recording, and time limitation. Future studies should focus on quantifying module feasibility, user satisfaction, and protocol adjustment for different settings.

Cell apoptosis induced by a synthetic carbazole compound LCY-2-CHO is mediated through activation of caspase and mitochondrial pathways.

The mechanisms involved in the apoptotic effect of LCY-2-CHO [9-(2-chlorobenzyl)-9H-carbazole-3-carbaldehyde], a synthetic carbazole derivative identified as an anti-inflammatory compound, were studied. Cell cycle analysis by propidium iodide staining in human THP-1 monocytic leukemia cells showed the ability of LCY-2-CHO to increase cell population in sub-G1 stage with time- and concentration-dependent manners. LCY-2-CHO-mediated cell death was also demonstrated by DNA laddering and was not related to the release of lactate dehydrogenase. Apoptosis in THP-1 cells induced by LCY-2-CHO was accompanied by the Bid cleavage, collapse of mitochondrial transmembrane potential, the release of cytochrome c and the activation of caspase-3. The apoptotic effect of LCY-2-CHO was diminished by the presence of zVEID-fmk (caspase-6 inhibitor), zIETD-fmk (caspase-8 inhibitor), and zVAD-fmk (non-selective caspase inhibitor), but was not altered by several antioxidants, and cathepsin inhibitor. The Bid cleavage and loss of mitochondrial transmembrane potential, but not the cytochrome c release, were reversed by zIETD-fmk. Comparing the cell selectivity of LCY-2-CHO, we found T-cell acute lymphoblastic CEM leukemia cells were sensitive to 1 microM LCY-2-CHO, acute myeloid leukemia HL-60 cells underwent apoptosis at 10 microM, while adherent cancer cells, such as PC3, HT29 and MCF-7, were resistant to 30 microM LCY-2-CHO within 24-h incubation. Taken together in the present study, we demonstrated LCY-2-CHO might be apoptotic for malignant hematopoietic cells but not anchorage-dependent cells. This action is mediated by an intrinsic caspase-dependent apoptotic event involving mitochondria.

PKA-dependent activation of PKC, p38 MAPK and IKK in macrophage: implication in the induction of inducible nitric oxide synthase and interleukin-6 by dibutyryl cAMP.

In this study, we examined the signal transduction of dibutyryl cyclic adenosine monophosphate (dBcAMP) to stimulate the release of nitric oxide (NO) and interleukin-6 (IL-6) from J774 macrophages. These actions of dBcAMP were diminished by the presence of the inhibitors of protein kinase A (PKA), protein kinase C (PKC), p38 MAPK and nuclear factor-kappa B (NF-kappaB). In contrast, Go 6976 and PD98059 had no significant effects. Consistently, dBcAMP caused membrane translocation of PKCbetaII, delta, mu, lambda and zeta isoforms, and increased atypical protein kinase C (aPKC) and p38 MAPK activities. The nuclear translocation and DNA-binding study revealed that dBcAMP stimulated NF-kappaB, activator protein-1 (AP-1), and CAAT/enhancer-binding protein (c/EBPbeta). Via PKA, PKC and p38 MAPK-dependent signals, dBcAMP also induced inhibitory subunit of NF-kappaB (IkappaB) degradation, IkappaB kinase (IKK) activation, nuclear translocation of NF-kappaB subunit p65 and its association with the CREB-binding protein (CBP). These results illustrate that PKA activation in macrophages is able to stimulate PKC and p38 MAPK, which lead to IKK-dependent NF-kappaB activation and contribute to the induction of inducible nitric oxide synthase (iNOS) and IL-6 genes.

Inhibition of cytokine-induced JAK-STAT signalling pathways by an endonuclease inhibitor aurintricarboxylic acid.

1. Inducible nitric oxide (iNOS) is thought to involve in host defence and tissue damage in inflammatory loci. In previous study, we have found that the endonuclease inhibitor aurintricarboxylic acid (ATA) can protect macrophages from cell death induced by bacterial lipopolysaccharide. This action is through the interruption with signalling pathways for NF-kappa B and AP-1 activation, and thus iNOS expression. In this study we have addressed the effects of ATA on JAK-STAT signalling pathways. 2. In murine RAW 264.7 macrophages, IFN-gamma-mediated NO production and iNOS expression were concentration-dependently reduced by the presence of 3-100 micro M ATA. 3. IFN-gamma-induced STAT1 activation, as assessed from its tyrosine phosphorylation, nuclear translocation, binding to specific DNA response element and evoked IRF-1 reporter gene assay, were concomitantly inhibited by ATA. However, ATA did not alter IFN-gamma binding to RAW 264.7 cells. 4. The activities of JAK1 and JAK2, the upstream kinases essential for STAT1 signalling in response to IFN-gamma, were also reduced by ATA. 5. Moreover, IL-4, IL-10, GM-CSF and M-CSF elicited tyrosine phosphorylation of STAT3, STAT5 and/or STAT6 in macrophages were diminished by the presence of ATA. 6. Taken together, we conclude that ATA can interfere JAK-STAT signalling pathways in response to cytokines. This action contributes to the inhibition of IFN-gamma-induced iNOS expression.

Computational study of estrogen receptor-alpha antagonist with three-dimensional quantitative structure-activity relationship, support vector regression, and linear regression methods.

Human estrogen receptor (ER) isoforms, ERα and ERß, have long been an important focus in the field of biology. To better understand the structural features associated with the binding of ERα ligands to ERα and modulate their function, several QSAR models, including CoMFA, CoMSIA, SVR, and LR methods, have been employed to predict the inhibitory activity of 68 raloxifene derivatives. In the SVR and LR modeling, 11 descriptors were selected through feature ranking and sequential feature addition/deletion to generate equations to predict the inhibitory activity toward ERα. Among four descriptors that constantly appear in various generated equations, two agree with CoMFA and CoMSIA steric fields and another two can be correlated to a calculated electrostatic potential of ERα.

Differential regulation of interleukin-8 gene transcription by death receptor 3 (DR3) and type I TNF receptor (TNFRI).

TL1A induces interleukin-8 (IL-8) secretion in human peripheral blood monocyte-derived macrophage in a dose- and time-dependent manner. Overexpression of its cognate receptor DR3 can induce a higher amount of IL-8 protein secretion than that induced by TNFRI even though both receptors activate IL-8 gene transcription in a similar fashion. The underlying mechanism for the regulation of the IL-8 gene transcription by DR3 has not been investigated yet. Here, we used HEK293 cells as a model system to dissect the possible signaling components that are involved in the regulation of DR3-mediated IL-8 gene expression. Although both DR3 and TNFRI activated TRAF2 and NF-kappaB to induce IL-8 gene transcription, the kinase cascades that transduce signals for DR3- and TNFRI-induced IL-8 gene transcription are different. The axis TAK1/ASK1-MKK4/MKK7-JNK2 is responsible for DR3-mediated IL-8 gene expression whereas the axis ASK1-MKK4-JNK1/JNK2/p38MAPK is the choice for TNFRI-mediated activation of IL-8 gene expression. This indicates that the downstream signaling pathways of DR3 and TNFRI for IL-8 secretion are divergent even though both receptors contain death-domain and induce IL-8 secretion via TRAF2.

Proteasome inhibitors induce peroxisome proliferator-activated receptor transactivation through RXR accumulation and a protein kinase C-dependent pathway.

Peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of nuclear hormone receptors, forms a heterodimeric DNA binding complex with retinoid X receptor (RXR) and serves as a transcriptional regulator of gene expression. In this study, using luciferase assay of a reporter gene containing PPAR response element (PPRE), we found PPRE transactivity was additively induced by PPAR gamma activator (15dPGJ2) and RXR activator (9-cis retinoic acid, 9-cis RA). Proteasome inhibitors MG132 and MG262 also stimulate PPRE transactivity in a concentration-dependent manner, and this effect is synergistic to 15dPGJ2 and 9-cis RA. PKC activation by 12-myristate 13-acetate (PMA) and ingenol 3,20-dibenzoate (IDB) also led to an increased PPRE activation, and this action was additive to PPAR gamma activators and 9-cis RA, but not to proteasome inhibitors. Results indicate that the PPAR gamma enhancing effect of proteasome inhibitors was attributed to redox-sensitive PKC activation. Western blot analysis showed that the protein level of RXR alpha, but not PPAR gamma, RXR beta, or PKC isoforms, was accumulated in the presence of proteasome inhibitors. Taken together, we conclude that proteasome inhibitors can upregulate PPRE activity through RXR alpha accumulation and a PKC-dependent pathway. The former is due to inhibition of RXR alpha degradation through ubiquitin-dependent proteasome system, while the latter is mediated by reactive oxygen species (ROS) production.

Proinflammatory effects of LIGHT through HVEM and LTbetaR interactions in cultured human umbilical vein endothelial cells.

Members of the tumor necrosis factor (TNF) receptor (TNFR) superfamily are known to be potent mediators of immune responses. LIGHT is a member of the TNF superfamily, and its receptors have been identified as lymphotoxin beta receptor (LTbetaR), herpes virus entry mediator (HVEM), and decoy receptor 3 (DcR3). LIGHT can induce either cell death and/or NF-kappaB activation via its interaction with LTbetaR and/or HVEM. In this study, we investigated the effects of LIGHT in human umbilical vein endothelial cells (HUVECs). We demonstrated that both LTbetaR and HVEM, but not DcR3, are present in HUVECs, and LIGHT can induce the secretion of chemokines (IL-8 and GRO-alpha), cell surface expression of adhesion molecules (ICAM-1 and VCAM-1), PGI2 release, and COX-2 expression. However, the LIGHT mutein, LIGHT-R228E, which has been shown to exhibit binding specificity to LTbetaR, could not induce the secretion of GRO-alpha, PGI2, or the expression of COX-2. These results indicate that both LTbetaR and HVEM can discriminatively mediate the expression of different genes in HUVECs, and suggest that LIGHT is a proinflammatory cytokine.

Mechanism of LIGHT/interferon-gamma-induced cell death in HT-29 cells.

LIGHT is a member of tumor necrosis factor (TNF) superfamily, and previous studies have indicated that in the presence of interferon-gamma (IFN-gamma), LIGHT through LTbetaR signaling can induce cell death with features unlike classic apoptosis. In present study, we investigated the mechanism of LIGHT/IFN-gamma-induced cell death in HT-29 cells, where the cell death was profoundly induced when sub-toxic concentrations of LIGHT and IFN-gamma were co-treated. LIGHT/IFN-gamma-induced cell death was accompanied by DNA fragmentation and slight LDH release. This effect was not affected by caspase, JNK nor cathepsin B inhibitors, but was partially prevented by p38 mitogen-activated protein kinase (MAPK) and poly (ADP-ribose) polymerase (PARP) inhibitors, and abolished by aurintricarboxylic acid (ATA), which is an inhibitor of endonuclease and STATs signaling of IFN-gamma. Immunobloting reveals that LIGHT/IFN-gamma could induce p38 MAPK activity, Bak and Fas expression, but down-regulate Mcl-1. Besides, LIGHT/IFN-gamma could not activate caspase-3 and -9, but decreased mitochondrial membrane potential. Although LIGHT could not affect IFN-gamma-induced STAT1 phosphorylation and transactivation activity, which was required for the sensitization of cell death, survival NF-kappaB signaling of LIGHT was inhibited by IFN-gamma. These data suggest that co-presence of LIGHT and IFN-gamma can induce an integrated interaction in signaling pathways, which lead to mitochondrial dysfunction and mix-type cell death, not involving caspase activation.

Lymphotoxin beta receptor induces interleukin 8 gene expression via NF-kappaB and AP-1 activation.

The human lymphotoxin beta receptor (LTbetaR), a member of the tumor necrosis factor (TNF) receptor superfamily, is essential for not only the development and organization of secondary lymphoid tissues, but also for chemokine release. Even though LTbetaR was shown to recruit TNF-receptor-associated factor (TRAF) 2, 3, and 5, and to induce cell apoptosis or NF-kappaB activation, however, the downstream signaling leading to chemokine expression is not illustrated yet. In this study, we find that overexpression of LTbetaR in HEK293 cells increases IL-8 promoter activity and leads to IL-8 release. LTbetaR-induced IL-8 gene expression requires NF-kappaB (-80 to -71) and AP-1 (-126 to -12) binding sites located in IL-8 promoter, and NF-kappaB is more crucial than AP-1 for IL-8 gene expression. Reporter assay with dominant-negative mutants of TRAFs reveals that TRAF2, 3, and 5, as well as the downstream signal molecules NIK, IKKalpha, and IKKbeta, are involved in IL-8 gene expression. LTbetaR-mediated IL-8 response was inhibited by the dominant-negative mutants of ASK1, MKK4, MKK7, and JNK, but not by those of MEKK1, TAK1, MEK, ERK, and p38 MAPK. This suggests that IL-8 induction by LTbetaR is via TRAFs-elicited signaling pathways, including NIK/IKK-dependent NF-kappaB activation and ASK/MKK/JNK-dependent AP-1 activation.

Inhibition of IFN-gamma-mediated inducible nitric oxide synthase induction by the peroxisome proliferator-activated receptor gamma agonist, 15-deoxy-delta 12,14-prostaglandin J2, involves inhibition of the upstream Janus kinase/STAT1 signaling pathway.

Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands have been reported to exert anti-inflammatory activities in macrophages by competition for transcriptional coactivators with some transcriptional factors, including NF-kappaB. In the present study the influence of PPARgamma activators on IFN-gamma-elicited macrophage stimulation and signaling cascades was investigated. The results show that IFN-gamma-induced inducible NO synthase (iNOS) gene transcription, iNOS protein induction, and NO production are more sensitive to inhibition by 15-deoxy-Delta(12,14)-prostaglandin J(2) (15dPGJ(2)) than by the other two PPARgamma agonists, GW1929 and ciglitazone. Delayed addition of 15dPGJ(2) for 2 h resulted in reduced inhibition, suggesting action by 15dPGJ(2) on the upstream signaling cascades. Immunoblotting, DNA binding, and reporter gene assays consistently revealed the inhibitory ability of 15dPGJ(2), but not GW1929 or ciglitazone, on IFN-gamma-elicited signaling cascades, including tyrosine phosphorylation of Janus tyrosine protein kinase 2 and STAT1, DNA binding, and IFN regulatory factor-1 trans-activation of STAT1. These effects of 15dPGJ(2) were not abrogated by the PPARgamma antagonist, bisphenol A diglycidyl ether, indicating the PPARgamma-independent actions. 15dPGJ(2) also attenuated IL-6-induced tyrosine phosphorylation of STAT1 and STAT3 in Hep3B hepatoma cells. Consistent with the inhibitory effect of reactive oxygen species on STAT1 signaling, STAT1 inhibition by 15dPGJ(2) was abrogated by N-acetylcysteine, glutathione, superoxide dismutase, and catalase. Furthermore, 15dPGJ(2)-induced inhibition of STAT1 phosphorylation and NO production still occurred in the presence of peroxovanadate, ruling out the action mechanism of 15dPGJ(2) on tyrosine phosphatase. Taken together, for the first time in this study we demonstrate that 15dPGJ(2) can inhibit cytokine-stimulated Janus kinase 2-STAT signaling through a PPARgamma-independent, reactive oxygen species-dependent mechanism. These data provide a novel molecular mechanism of iNOS inhibition by 15dPGJ(2) and confirm its physiological role in anti-inflammation.

Silymarin protects dopaminergic neurons against lipopolysaccharide-induced neurotoxicity by inhibiting microglia activation.

An inflammatory response in the central nervous system mediated by activation of microglia is a key event in the early stages of the development of neurodegenerative diseases. Silymarin is a polyphenolic flavanoid derived from milk thistle that has anti-inflammatory, cytoprotective and anticarcinogenic effects. In this study, we first investigated the neuroprotective effect of silymarin against lipopolysaccharide (LPS)-induced neurotoxicity in mesencephalic mixed neuron-glia cultures. The results showed that silymarin significantly inhibited the LPS-induced activation of microglia and the production of inflammatory mediators, such as tumour necrosis factor-alpha and nitric oxide (NO), and reduced the damage to dopaminergic neurons. Therefore, the inhibitory mechanisms of silymarin on microglia activation were studied further. The production of inducible nitric oxide synthase (iNOS) was studied in LPS-stimulated BV-2 cells as a model of microglia activation. Silymarin significantly reduced the LPS-induced nitrite, iNOS mRNA and protein levels in a dose-dependent manner. Moreover, LPS could induce the activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase but not extracellular signal-regulated kinase. The LPS-induced production of NO was inhibited by the selective p38 MAPK inhibitor SB203580. These results indicated that the p38 MAPK signalling pathway was involved in the LPS-induced NO production. However, the activation of p38 MAPK was not inhibited by silymarin. Nevertheless, silymarin could effectively reduce LPS-induced superoxide generation and nuclear factor kappaB (NF-kappaB) activation. It suggests that the inhibitory effect of silymarin on microglia activation is mediated through the inhibition of NF-kappaB activation.