| Background Severe sepsis was defined by evidence of infection accompanied by systemic inflammatory response syndrome (SIRS) and in addition at least one acute organ dysfunction remote from the site of infection. It is the leading cause of death in intensive care unit patients. The incidence of sepsis continues to increase and despite use of highly effective anti-microbic chemotherapy and powerful supportive treatment, the mortality rate for patients with the sepsis syndrome remains high. It has recently been discovered that lipopolysaccharide(LPS) of gram-negative bacteria plays a pivotal role in the genesis of sepsis. Lipopolysaccharide binding protein (LBP) and its receptor CD14 are known to play important roles in the pathway leading to the sepsis caused by LPS. CD14 is present in a soluble form (sCD14) in blood and in a membrane-bound form(mCD14) on the surface of monocytes,macrophages and polymorphonuclear leukocytes. LBP can catalytically transfer raonomeric LPS from LPS aggregates onto mCD14 or sCD14 molecules and thus greatly enhance CD14-mediated response to LPS. In addition, like LBP, sCD14 also facilitates the transfer of LPS to HDL, resulting in the neutralization of LPS. Several abroad studies have reported that significantly increased LBP and sCD14 serum levels in patients with sepsis have some correlation with severity and prognostic parameters in sepsis.Objective The primary objective of the present study was to investigate the changes of serum LBP and sCD14 levels in the patients with severe sepsis. Secondary objectives were to assess the relationship between LBP or sCD14 levels and severity, and prognostic parameters in sepsis.Methods Severe sepsis was defined according to the American College Of Chest Physician/Society Of Critical Care Medicine Consensus Conference (ACCP/SCCM) in 1991. Forty-one patients(age range 31-81 years, median 59. 9 16.4 years,28 men, 13 women), who fulfilled the diagnostic criteria. At study entry each patient's history and physical were recorded. Scores for the Acute Physiology and Chronic Health Evaluation (APACHE II) were determined with the use of a specific intensive care database. Routine laboratory parameters such as blood routine and arterial blood gas and renal and liver function parameters were determined at days 0,1.2and5. Survivors or dead patients were assessed during a follow-up of as long as 28 days. Procalcitonin (PCT) and LPS were tested at study entry with 24h of onset of severe sepsis. Blood samples of 2ml were obtained at study entry with24h of onset of severe sepsis (day 0) and at day 1,2 and 5 from arterial line. Samples were collected in plastic tubes. Serum was prepared, following coagulation , by centrifugation at 2000 g at room temperature for 20 min?aliquoted and stored in plastic tube at -20 until assayed A control group was comprised of 20 healthy persons (age range 29-80 years, medain 62.9 ± 14.6 years, 12 men, 8 women) who take part in physical at a same period out-patient. There was no significantly difference of sex and years between study group and control group(P>0. 05). In the control group, only 1 sample was collected, stored at the same way. Serum concentration of LBP and sCD14 were measured by enzyme linked immuno-sorbent assay(ELlSA). The ELISAtest kits were produced by HyCult biotechnology company. Automatic rinsing/aspiration equipment extra vials of washing buffer was produced by the United States 620- RAD company, model 1575. Automatic spectrophotometer was from the German Humareader. The detection limit for the LBP and sCD14 was Ing/ml and 2ng/ml respectively. Plasma PCT concentrations were measured using an immunoassay with a sandwich technique and a chemiluminescent detection system, according to the manufacturers protocal (LumiTest). The sensitivity of analysis was approximately 0. Ing/ml. Endotoxin were measured using azo-display test with limulus reagent and synthetic ground substance of limulus.Results A total of 41 patients were included in the study. The infections included pneumonia...
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