Pcv-aCO2 and procalcitonin levels for the early diagnosis of bloodstream infections caused by gram-negative bacteria.

BACKGROUND: The central venous-to-arterial carbon dioxide difference (Pcv-aCO2) is a biomarker for tissue perfusion, but the diagnostic value of Pcv-aCO2 in bacteria bloodstream infections (BSI) caused by gram-negative (GN) bacteria remains unclear. This study evaluated the expression levels and diagnostic value of Pcv-aCO2 and procalcitonin (PCT) in the early stages of GN bacteria BSI. METHODS: Patients with BSI admitted to the intensive care unit at Guangdong Provincial People's Hospital between August 2014 and August 2017 were enrolled. Pcv-aCO2 and PCT levels were evaluated in GN and gram-positive (GP) bacteria BSI patients. RESULTS: A total of 132 patients with BSI were enrolled. The Pcv-aCO2 (8.32 ± 3.59 vs 4.35 ± 2.24 mmHg p = 0.001) and PCT (30.62 ± 34.51 vs 4.92 ± 6.13 ng/ml p = 0.001) levels were significantly higher in the GN group than in the GP group. In the diagnosis of GN bacteria BSI, the area under the receiver operating characteristic curve (AUROC) for Pcv-aCO2 was 0.823 (95% confidence interval (CI): 0.746-0.900). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 71.90%, 88.00%, 74.07% and 78.21%, respectively. The AUROC for PCT was 0.818 (95% CI: 0.745-0.890). The sensitivity, specificity, PPV and NPV were 57.90%, 94.67%, 71.93% and 74.67%, respectively. CONCLUSIONS: Pcv-aCO2 and PCT have similar and high diagnostic value for the early diagnosis of BSI caused by GN bacteria.

N-acetylcysteine and allopurinol confer synergy in attenuating myocardial ischemia injury via restoring HIF-1α/HO-1 signaling in diabetic rats.

OBJECTIVES: To determine whether or not the antioxidants N-acetylcysteine (NAC) and allopurinol (ALP) confer synergistic cardioprotection against myocardial ischemia/reperfusion (MI/R) injury by stabilizing hypoxia inducible factor 1α (HIF-1α)/heme oxygenase 1 (HO-1) signaling in diabetic myocardium. METHODS: Control or diabetic [streptozotocin (STZ)-induced] Sprague Dawley rats received vehicle or NAC, ALP or their combination for four weeks starting one week after STZ injection. The animals were then subjected to thirty minutes of coronary artery occlusion followed by two hours reperfusion in the absence or presence of the selective HO-1 inhibitor, tin protoporphyrin-IX (SnPP-IX) or the HIF-1α inhibitor 2-Methoxyestradiol (2ME2). Cardiomyocytes exposed to high glucose were subjected to hypoxia/re-oxygenation in the presence or absence of HIF-1α and HO-1 achieved by gene knock-down with related siRNAs. RESULTS: Myocardial and plasma levels of 15-F2t-isoprostane, an index of oxidative stress, were significantly increased in diabetic rats while cardiac HO-1 protein and activity were reduced; this was accompanied with reduced cardiac protein levels of HIF-1α, and increased post-ischemic myocardial infarct size and cellular injury. NAC and ALP given alone and in particular their combination normalized cardiac levels of HO-1 and HIF-1α protein expression and prevented the increase in 15-F2t-isoprostane, resulting in significantly attenuated post-ischemic myocardial infarction. NAC and ALP also attenuated high glucose-induced post-hypoxic cardiomyocyte death in vitro. However, all the above protective effects of NAC and ALP were cancelled either by inhibition of HO-1 or HIF-1α with SnPP-IX and 2ME2 in vivo or by HO-1 or HIF-1α gene knock-down in vitro. CONCLUSION: NAC and ALP confer synergistic cardioprotection in diabetes via restoration of cardiac HIF-1α and HO-1 signaling.

A simple modification results in greater success in the model of coronary artery ligation and myocardial ischemia in mice.

Mouse models of myocardial ischemic preconditioning (IPC) and ischemic postconditioning (IPD) have proven to be very useful models of cardiovascular diseases. In 2010, Gao described a novel procedure without the aid of mechanical ventilation. However, the technique of heart externalization could not be applied to mouse models of IPC or IPD due to the limited time frame of the technique. We proposed a modified simple and safe method using lung recruitment and short-term ventilation to perform the procedure in mice with IPC or IPD. The mice were randomly divided into 4 groups: the modified groups, M-IPC and M-IPD, and the conventional groups, C-IPC and C-IPD. In the 2 modified groups, the mice were removed from the ventilator and allowed to resume breathing spontaneously upon completion of the lung recruitment and the rapid closure of the thorax. Our study demonstrated that the postoperative recovery time was significantly reduced for the modified groups compared with the 2 conventional groups. Moreover, the inflammatory damages were attenuated by the modified method compared with the conventional method. In addition, the modified method significantly increased the survival rates of mice with IPC or IPD. The modified method improved the survival rates of mouse models of myocardial ischemia.

Endothelial nitric oxide synthase enhancer for protection of endothelial function from asymmetric dimethylarginine-induced injury in human internal thoracic artery.

OBJECTIVES: Endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine is a cardiovascular risk factor that is elevated in patients with coronary artery disease. We hypothesized that novel endothelial nitric oxide synthase enhancer AVE3085 might improve the endothelial function altered by asymmetric dimethylarginine in the human internal thoracic artery. METHODS: Cumulative concentration-relaxation curves to acetylcholine (-11 to -5 log mol/L) were established in left internal thoracic artery rings (n = 65) from 27 patients undergoing coronary artery bypass grafting in precontraction induced by U46619 (-8 log mol/L) in the absence or presence of asymmetric dimethylarginine (100 µmol/L) or AVE3085 (30 µmol/L). Protein expressions of endothelial nitric oxide synthase and levels of superoxide anion production were detected. RESULTS: Maximal relaxation induced by acetylcholine was significantly attenuated by asymmetric dimethylarginine (12.7% ± 2.3% vs 35.3% ± 5.0% in control; P < .05) and significantly restored by AVE3085 (23.4% ± 2.8%; P < .05). AVE3085 also markedly restored endothelial nitric oxide synthase expression (0.29 ± 0.008; P = .012) reduced by asymmetric dimethylarginine (0.05 ± 0.04 vs 0.36 ± 0.03 in control; P = .014). Increased superoxide anion production by asymmetric dimethylarginine (2.97 ± 0.25 vs 0.51 ± 0.10 relative light units/[s/mg] in control; P < .05) was inhibited by AVE3805 (0.62 ± 0.104 relative light units/[s/mg]; P < .05). CONCLUSIONS: AVE3085 may restore endothelium-dependent relaxation reduced by asymmetric dimethylarginine through upregulation of endothelial nitric oxide synthase expression and inhibition of production of superoxide anion in human internal thoracic artery. These findings provide new insights into endothelial protection of coronary bypass grafting vessels to improve long-term patency of grafts.

Remote ischaemic preconditioning reduces myocardial injury in patients undergoing heart valve surgery: randomised controlled trial.

OBJECTIVE: To determine whether remote ischaemic preconditioning (RIPC) is cardioprotective in patients undergoing heart valve replacement. DESIGN: Single-blinded, randomised controlled trial. SETTING: Tertiary referral hospital in China. PATIENTS: Adult patients (31-72 years) undergoing mitral valve, aortic valve or tricuspid valve surgery. INTERVENTIONS: Patients were randomised to either the RIPC (n=38) or control (n=35) group. After induction of anaesthesia, patients in the RIPC group underwent three 5 min cycles of right upper limb ischaemia, induced by an automated cuff-inflator placed on the upper arm and inflated to 200 mm Hg. Each cycle was interrupted by a 5 min period of reperfusion during which time the cuff was deflated. The control group had only a deflated cuff placed on the upper arm for 30 min. MAIN OUTCOME MEASURES: Serum troponin I concentration was measured before surgery and at 6, 12, 24, 48, and 72 h postoperatively. The cardiac function of all patients was followed postoperatively. RESULTS: Troponin I concentration was reduced in the RIPC group (398.7±179.3 µg/l) compared with the control group (708.4±242.5 µg/l). Mean difference was 309.7±50.8 (95% CI 210.1 to 409.3, p<0.0001). A greater improvement in postsurgical cardiac function was noted in the RIPC group than in the control group. CONCLUSIONS: These data indicate that RIPC reduces myocardial injury and improves cardiac function in patients undergoing heart valve surgery. TRIAL REGISTRATION NUMBER: NCT01175681.

[Construction, expression and functional characterization of single chain variable fragments (scFv) against human CD33 antigen].

AIM: To construct and express the single chain variable fragments (scFv) gene against human CD33 antigen, and characterize its bioactivity. METHODS: The genes encoding the light and heavy chain variable regions were cloned by RT-PCR from a murine hybridoma cell line, which could produce monoclonal antibody(mAb) against human CD33 antigen. Then the light and heavy chain variable regions were fused together by a short peptide linker containing 15 amino acid (Gly(4)Ser)(3) using splice-overlap extensive PCR. The recombinant anti-CD33 scFv was subcloned into the expression vector pET28a(+) and expressed in E.coli Rosetta after induction by IPTG. RESULTS: SDS-PAGE and Western blot analysis showed that the recombinant anti-CD33 scFv gene was expressed in the form of inclusion body in E.coli Rosetta, and the purified fusion protein was obtained after a series of purification steps including cell lysis, inclusion body solubilization, Ni(2+) metal affinity chromatography and protein refolding. Flow cytometry(FCM) analysis showed that the scFv could react with human CD33 antigen. CONCLUSION: Recombinant anti-CD33 scFv gene has been successfully constructed and expressed in E.coli Rosetta, which could provide foundation for the future target therapy to the myeloid leukemia.

Production of a monoclonal antibody against SARS-CoV spike protein with single intrasplenic immunization of plasmid DNA.

Severe acute respiratory syndrome (SARS) is a highly infectious disease caused by a novel coronavirus (SARS-CoV). Specific monoclonal antibodies (mAbs) against the SARS-CoV are vital for early diagnosis and pathological studies of SARS. Direct intrasplenic inoculation of plasmid DNA encoding antigen is an effective and fast approach to generate specific mAb when the protein antigen is difficult to prepare or dangerous in use. In this study, we selected one fragment of SARS-CoV spike protein (S1-(3)) as antigenic determinant by immunoinformatics. Single intrasplenic immunization of plasmid DNA encoding S1-(3) induced anti-spike protein antibodies. We established one hybridoma cell line secreting specific mAb and evaluated this mAb with murine leukemia virus pseudotyped with SARS-CoV spike protein (MLV/SARS-CoV). The mAb could recognize the spike protein on the MLV/SARS-CoV-infected Vero E6 cells albeit with no neutralizing effect on the infectivity of the pseudotype virus. Our results show that a single-shot intrasplenic DNA immunization is efficient for the production of specific mAb against SARS spike protein, and a linear epitope of the spike protein is recognized in this study.