Effect of Si3N4 Additive on Microstructure and Mechanical Properties of Ti(C,N)-Based Cermet Cutting Tools.

Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α-Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MPa.m1/2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets.

Alpha-Lipoic Acid Suppresses Extracellular Histone-Induced Release of the Infammatory Mediator Tumor Necrosis Factor-α by Macrophages.

BACKGROUND/AIMS: This study investigated signaling pathways via which extracellular histones induce the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) release from the macrophage cell line RAW 264.7 and the anti-inflammatory efficacy of the antioxidant alpha-lipoic acid (ALA). METHODS: ELISA and western blotting analyses were conducted to detect the release of TNF-α from histone-stimulated RAW 264.7 macrophages and the associated phospho-activation of MAPKs (ERK and p38) and NF-κB p65. The effects of ALA on the release of TNF-α and phospho-activation of the MAPKs and NF-κB p65 were studied. P < 0.05 was considered statistically significant. RESULTS: Extracellular histones dose-dependently induced TNF-α release from RAW 264.7 cells and increased the phosphorylation of p38, ERK, and NF-κB p65. TNF-α release was markedly suppressed by p38, ERK, and NF-kB inhibitors. ALA reduced histone-induced TNF-α release, ERK/p38 MAPK activation, and NF-kB activation without affecting macrophage viability. CONCLUSION: Histones induce TNF-α release from macrophages by activating the MAPK and NF-kB signaling pathways, while ALA suppresses this response by inhibiting ERK, p38 and NF-kB. These findings identify potentially critical inflammatory signaling pathways in sepsis and molecular targets for sepsis treatment.

Procalcitonin levels in patients with positive blood culture, positive body fluid culture, sepsis, and severe sepsis: a cross-sectional study.

BACKGROUND: Numerous investigations on procalcitonin (PCT) have been carried out, although few with large sample size. To deal with the complexity of sepsis, an understanding of PCT in heterogeneous clinical conditions is required. METHODS: Hospitalized patients aged 10-79 years were included in this retrospective and cross-sectional study. PCT tests were assayed within 2 days of blood culture. RESULTS: A total of 2952 cases (from 2538 patients) were enrolled in this study, including 440 cases in the 'positive BC' group, 123 cases in the 'positive body fluid culture' group, and 2389 cases in the 'negative all culture' group. Median PCT values were 4.53 ng/ml, 2.95 ng/ml, and 0.49 ng/ml, respectively. Median PCT values in the gram-negative BC group and gram-positive BC group, respectively, were 6.99 ng/ml and 2.96 ng/ml. Median PCT values in the 'positive hydrothorax culture' group, 'positive ascites culture' group, 'positive bile culture' group, and 'positive cerebrospinal fluid culture' group, respectively, were 1.39 ng/ml, 8.32 ng/ml, 5.98 ng/ml, and 0.46 ng/ml. In all, 357 cases were classified into the 'sepsis' group, 150 of them were classified into the 'severe sepsis' group. Median PCT values were 5.63 ng/ml and 11.06 ng/ml, respectively. CONCLUSIONS: PCT could be used in clinical algorithms to diagnose positive infections and sepsis. Different PCT levels could be related to different kinds of microbemia, different infection sites, and differing severity of sepsis.

[Intensive hemoperfusion and long-term hemofiltration for treatment of paraquat poisoning: a case report].

OBJECTIVE: A 20-year-old male patient was admitted in our department 14 h after paraquat poisoning at the dose of about 50 mL. The patient underwent intensive hemoperfusion for 2 h (3 times a day) for 9 consecutive days and received continuous renal replacement therapy (CRRT) in the mode of continuous veno-venous hemofiltration (CVVH) for 10 consecutive days in addition to routine medications. The biochemical indexes were monitored during the therapy. After the treatment, paraquat concentrations in the blood and urine were decreased, and the patient's urine volume (UV) increased, serum creatinine (Cr) level decreased, and the oxygenation index became normal. Dynamic CT scan showed no obvious pulmonary fibrosis. The patient was followed up for 6 months after discharge and no complaint of discomforts was reported. This case suggests that early intensive hemoperfusion and long-term CVVH may help improve the prognosis after paraquat poisoning.

Histones-mediated lymphocyte apoptosis during sepsis is dependent on p38 phosphorylation and mitochondrial permeability transition.

Lymphocyte apoptosis is one reason for immunoparalysis seen in sepsis, although the triggers are unknown. We hypothesized that molecules in plasma, which are up-regulated during sepsis, may be responsible for this. In this study, peripheral lymphocyte apoptosis caused by extracellular histones was confirmed both in mouse and human primary lymphocytes, in which histones induced lymphocyte apoptosis dose-dependently and time-dependently. To identify which intracellular signal pathways were activated, phosphorylation of various mitogen-activated protein kinases (MAPKs) were evaluated during this process, and p38 inhibitor (SB203580) was used to confirm the role of p38 in lymphocyte apoptosis induced by histones. To investigate the mitochondrial injury during these processes, we analyzed Bcl2 degradation and Rhodamine 123 to assess mitochondrial-membrane stability, via cyclosporin A as an inhibitor for mitochondrial permeability transition (MPT). Then, caspase 3 activation was also checked by western-blotting. We found that p38 phosphorylation, mitochondrial injury and caspase 3 activation occurred dose-dependently in histones-mediated lymphocyte apoptosis. We also observed that p38 inhibitor SB203580 decreased lymphocyte apoptotic ratio by 49% (P<0.05), and inhibition of MPT protected lymphocytes from apoptosis. Furthermore, to investigate whether histones are responsible for lymphocyte apoptosis, various concentrations of histone H4 neutralization antibodies were co-cultured with human primary lymphocytes and plasma from cecal ligation and puncture (CLP) mice or sham mice. The results showed that H4 neutralization antibody dose-dependently blocked lymphocyte apoptosis caused by septic plasma in vitro. These data demonstrate for the first time that extracellular histones, especially H4, play a vital role in lymphocyte apoptosis during sepsis which is dependent on p38 phosphorylation and mitochondrial permeability transition. Neutralizing H4 can inhibit lymphocyte apoptosis, indicating that it could be a potential target in clinical interventions for sepsis associated immunoparalysis.

[Fluid resuscitation strategy in septic shock following urinary infection with severe pulmonary capillary leakage].

OBJECTIVE: To characterize septic shock following urinary infection with severe pulmonary capillary leakage, and to evaluate the fluid therapy on treatment of hypovolemic shock and the role of transpulmonary thermodilution technique with pulse induced continuous cardiac output (PiCCO) monitoring. METHODS: A retrospective study was conducted. Eight patients surviving septic shock following urinary infection with severe pulmonary capillary leakage were enrolled, and all of them underwent PiCCO monitoring in the intensive care unit (ICU) when the diagnosis was established. The monitoring started at admission, and ended when shock was corrected or transferred from ICU. The clinical data including general end diastolic volume index (GEDVI), extravascular lung water index (EVLWI), input and output volume of fluid, net fluid balance, oxygenation index (PaO2/FiO2), the level of arterial blood lactic acid, and chest X ray were collected and analyzed retrospectively the characteristics of septic shock following urinary infection, and the role of PiCCO monitoring in fluid resuscitation. RESULTS: Septic shock following urinary infection occurred in a median of 4.5 days in 8 patients after renal and ureteric calculi lithotripsy, accompanied with severe pulmonary vessel effusion and hypoxemia in different degrees. The mean value of EVLWI was (22±7) ml/kg, and the PaO2/FiO2 (164±82) mm Hg at the time of admission to ICU. Conservative fluid resuscitation strategy was adopted in management of septic shock with severe pulmonary capillary leakage, the mean fluid input in 8 patients was (2412±1121) ml/d, and the net fluid balance -553 ml/d, and the central venous pressure (CVP) and GEDVI were maintained at levels of (9±3) mm Hg and (749±236) ml/m(2) respectively. Diuretics were administered to 6 patients and the mean dosage of fursemide was (264±133) mg. Norepinephrine and dobutamine infusion were given to 7 patients to maintain blood pressure at normal range for (4±1) days. Seven patients were mechanically ventilated, and the mean length of ventilation was (8±6) days. All of the 8 patients survived from septic shock after fluid resuscitation therapy, with the mean level of EVLWI decreased gradually to (11±3) ml/kg, and the lung effusion was absorbed significantly as shown in chest X ray. The mean length of ICU stay was (17±11) days. Pearson correlate analysis showed EVLWI was significantly correlated with PaO(2)/FiO(2) and the levels of artery blood serum lactate, with r -0.91 and 0.70 respectively (both P<0.05). CONCLUSIONS: Successful management of septic shock following urinary infection with severe pulmonary vascular leakage is based on accurate assessment of blood volume status, especially the degree of EVLWI, emphasis on prevention of EVLWI increase, and adoption of conservative fluid resuscitation strategies according to hemodynamic monitoring parameters. PiCCO monitoring is a useful tool in assessment of the blood volume status and management of fluid resuscitation in patients with urinary lithotripsy-associated septic shock complicated with severe pulmonary edema.

Synergistic inhibitory effects by the combination of gefitinib and genistein on NSCLC with acquired drug-resistance in vitro and in vivo.

In clinical practice, most patients with non small cell lung cancer (NSCLC) who respond to tyrosine kinase inhibitors eventually progress because of an acquired resistance mutation, T790M, in epidermal growth factor receptor (EGFR). Thus, it is important to identify a new drug to reduce resistance. The aim of this study was to test whether genistein combined with gefitinib is effective against NSCLC in a cell line carrying T790M, and to clarify the underlying mechanisms. The human lung cancer cell line H1975 was used as an in vitro and in vivo model. Cells were treated with gefitinib, genistein, or a combination at a range of concentrations. Cell proliferation was calculated to assess the anticancer effects of the compounds in vitro. Flow cytometry and Western blotting were employed to determine the inhibitory effects on proliferation and the induction of apoptosis. The in vivo effects of the compounds were examined using a xenografted nude mouse model for validation. Gefitinib together with genistein enhanced both growth inhibition and apoptosis; however, the greatest synergistic effect was observed at low concentrations. p-EGFR, p-Akt, and p-mTOR expressions in vitro were reduced more by the combined use of the drugs, whereas caspase-3 and PARP activities were increased. Significantly more tumor growth inhibition was detected following combination treatment in the in vivo model. These findings suggest that genistein enhanced the antitumor effects of gefitinib in a NSCLC cell line carrying the T790M mutation. This synergistic activity may be due to increased inhibition of the downstream molecular and pro-apoptotic effects of EGFR.

[Impact of transfusion of apoptotic and necrotic thymocytes on the survival of mice with sepsis].

OBJECTIVE: To investigate the effect of transfusion of apoptotic and necrotic thymocytes prior to sepsis on the survival rate of mice. METHODS: BALB/c mice are divided into 3 groups and received intravenous injection of PBS (control), apoptotic thymocytes, or necrotic thymocytes. Three days later, cecal ligation and puncture (CLP) were performed to induce sepsis in these mice, and their survival and organ damage were observed. RESULTS: The survival rates of mice in PBS group was 44.6% at the end of first week after CLP, and obvious lung and kidney damages were observed. A significant increase in the survival rate was found in apoptotic cell transfusion group (69.6%, P=0.012), with also lessened lung and kidney damages. The survival rate of mice in necrotic cell transfusion group was only 31.6% at 2 weeks, significantly lower than that in PBS group (P=0.035), and the lung and kidney damage was even more obvious. CONCLUSION: Transfusion of apoptotic thymocytes 3 days before induction of sepsis can reduce organ damage and improve the survival rate of mice, while necrotic cell transfusion produces the opposite effect.

[Differences in the response to sepsis between C57BL/6 and BALB/c mice].

OBJECTIVE: To compare the responses to sepsis between C57BL/6 and BALB/c mice. METHODS: Thirty C57BL/6 mice and 30 BALB/c mice were randomized into sham-operated group and sepsis group (n=15). Sepsis model was established by cecal ligation puncture (CLP) in the mice, and 6 h after the operation, 5 mice from each group were selected randomly for cytokine detection including IL-1beta, IL-2, IL-4, IL-5, IL-10, GM-CSF, IFN-gamma and TNF-alpha by Bio-plex. The other 10 mice in each group were used for survival analysis. RESULTS: The survival rates of BALB/c and C57BL/6 mice were both 100% in one week after the sham operation, but lowered to 10% and 50% in one week after CLP, respectively. The survival rate of C57BL/6 mice was significantly lower than that of BALB/c mice (P<0.05). After CLP, C57BL/6 mice showed significantly greater IL-4, TNF-alpha and IL-10 production than the sham-operated mice, but the concentrations of the 8 cytokines in BALB/c mice after CLP showed no significant increment. CONCLUSION: Compared with BALB/c mice, C57BL/6 strain mouse is more sensitive to sepsis.

[Effect of FK506 on cytokine secretion in whole blood].

OBJECTIVE: To investigate the effect of FK506 on cytokine secretions in whole blood from healthy individuals. METHODS: Blood samples collected from healthy volunteers were co-cultured with different concentrations of FK506 and stimulated with PMA and IONO. The concentrations of 8 cytokines including IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha, GM-CSF and G-CSF were detected by Bio-Plex suspension system. RESULTS: Compared with the control group, high-concentration FK506 (20 ng/ml) significantly inhibited the secretions of IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha, GM-CSF and G-CSF. At a moderate concentration (5 ng/ml), FK506 inhibited the secretion of GM-CSF significantly. CONCLUSION: FK506 effectively inhibits the secretion of proinflammatory cytokines including IL-6, IFN-gamma and TNF-alpha and also the secretion of IL-2, IL-12, IL-17, GM-CSF and G-CSF. FK506 might play the role of immunosuppression by inhibiting the production of these cytokines by the immune cells. Monitoring the levels of these cytokines might be a potential method for evaluating the adequacy of FK506 doses administered.

[Apoptosis induction of rhesus peripheral blood lymphocytes].

OBJECTIVE: To establish a method for inducing apoptosis of rhesus peripheral blood lymphocytes (PBLs). METHODS: Rhesus PBLs were irradiated with X-ray, (60)Co gamma-rays and ultraviolet (UVC254 nm), respectively, and the cell apoptosis was evaluated with flow cytometry using annexin-V staining and propidium iodide staining. RESULTS: X-ray and (60)Co gamma-ray irradiation induced only low apoptotic rates of the PBLs, and UVC resulted in the highest apoptotic rate of about 60%. UVC irradiation of the PBLs in RPMI supplemented with 10% heat-inactivated fetal calf serum for 60 min at a distance of 20 cm led to an early apoptotic rate of 58.85% and necrotic rate of 11.5%. The apoptotic rate of PBLs increased in a dose- and time-dependent fashion. CONCLUSION: For inducing apoptosis of the rhesus PBLs, UVC can be more effective than X-ray and (60)Co gamma-ray. The highest apoptotic rate can be achieved when the rhesus PBLs in RPMI supplemented with 10% heat-inactivated fetal calf serum are exposed to UVC for 60 min at the distance of 20 cm.