Effekte von Dopamin auf die zelluläre und humorale Immunantwort von Patienten mit Sepsis

Fabrication of a novel enzymatic electrochemical biosensor for determination of tyrosine in some food samples

In this work, fabrication of a novel and ultrasensitive electrochemical biosensor based on immobilization of tyrosine hydroxylase onto palladium-platinum bimetallic alloy nanoparticles/chitosan-1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide/graphene-multiwalled carbon nanotubes-IL/glassy carbon electrode for determination of L-tyrosine in some high tyrosine foods including cheese, egg and yogurt was reported. Immobilization of tyrosine hydroxylase onto the surface of the biosensor was performed by cross-linking tyrosine hydroxylase and chitosan through the addition of glutaraldehyde. Enzymatic biosensors employ the affinity and selectivity of catalytically active proteins towards their target molecules and here, the tyrosine hydroxylase selectively catalyzes the conversion of tyrosine to levodopa which can be oxidized at lower potentials than tyrosine. The modifications were characterized by electrochemical impedance spectroscopy, cyclic voltammetry, energy dispersive X-ray spectroscopic and scanning electron microscopy. Under optimal conditions, the biosensor detected tyrosine in concentration ranges of 0.01 × 10^-9 to 8.0 × 10^-9 mol L^-1 and 8.0 × 10^-9 to 160.0 × 10^-9 mol L^-1 with a limit of detection of 0.009 × 10^-9 mol L^-1. The biosensor was able to selective determination of tyrosine even in the presence of common interferents therefore, the biosensor was highly selective. The biosensor also showed good operational stability, antifouling properties, sensitivity, repeatability and reproducibility.

Biomarkers of inflammation in major vascular surgery: a prospective randomised trial

BACKGROUND

Surgery induces inflammation and pro-inflammatory cytokines are associated with post-operative complications. In cardiac surgery, it has been shown that volatile anaesthetics have cardioprotective properties. We explored whether sevoflurane affects the pro-inflammatory response favourably compared with total intravenous anaesthesia (TIVA) after surgery.

METHODS

We measured monocyte chemotactic protein 1 (MCP-1), matrix metalloproteinase 9 (MMP-9), C-reactive protein (CRP), vascular cell adhesion molecule 1 (VCAM-1), interleukin (IL)-6 and IL-8 perioperatively and evaluated if the anaesthetic regimen affected these mediators. Our hypothesis was that sevoflurane-based anaesthesia is associated with a reduced release of biomarkers of inflammation compared with TIVA with propofol/remifentanil.

RESULTS

In the total population, MCP-1, MMP-9, IL-6 and IL-8 increased 30 min after arrival intensive care unit, compared with before surgery (P < 0.001), whereas CRP and VCAM-1 transiently declined (P < 0.001). From 30 min after arrival intensive care unit to 1st post-operative day, MCP-1 and IL-6 levels declined (P < 0.001), CRP and VCAM-1 increased (P < 0.001), whereas MMP-9 and IL-8 were not significantly altered. Pre-operatively there were no significant differences in any variables between the two anaesthetic groups. Lower levels of MCP-1 and IL-8 (P < 0.001) and higher levels of IL-6 and MMP-9 (P = 0.003) were found in the sevoflurane group, compared with the TIVA group 30 min post-operatively. CRP and VCAM-1 levels did not differ. There were no significant differences between the two anaesthetic groups before surgery or at 1st post-operative day.

CONCLUSION

We found an inflammatory response during the observation period, which was modified by the anaesthetic regimen in the early phase. This short-lasting difference is probably too short to support a cardioprotective effect of sevoflurane compared with TIVA in open abdominal aortic surgery.