Age, creatinine and ejection fraction (ACEF) score: a simple risk-stratified method for infective endocarditis.

BACKGROUND: Older age, renal dysfunction and low left ventricular ejection fraction are accepted predictors of poor outcome in patients with infective endocarditis (IE). This study aimed to investigate the prognostic significance of the age, creatinine and ejection fraction (ACEF) score in IE. METHODS: The study involved 1019 IE patients, who were classified into three groups according to the tertiles of ACEF score: low ACEF (<0.6, n = 379), medium ACEF (0.6-0.8, n = 259) and high ACEF (>0.8, n = 381). The ACEF score was calculated as follows: age (years)/ejection fraction (%)+1 (if serum creatinine value was >2 mg/dL). The relationship between ACEF score and adverse events was analyzed. RESULTS: In-hospital mortality was 8.2%, which increased with the increase of ACEF score (4.2% vs. 5.0% vs. 14.4% for the low-, medium- and high-ACEF groups, respectively; P < 0.001). ACEF score had a good discriminative ability for predicting in-hospital death [areas under the curve (AUC), 0.706, P < 0.001]. The predictive value of ACEF score in surgical treatment was significantly higher than in conservative treatment for predicting in-hospital death (AUC, 0.812 vs. 0.625; P = 0.001). Multivariable analysis revealed that ACEF score was independently associated with in-hospital mortality (adjusted odds ratio, 2.82; P < 0.001) and long-term mortality (adjusted hazard ratio, 2.51; P < 0.001). CONCLUSION: ACEF was an independent predictor for in-hospital and long-term mortality in IE patients, and it could be considered as a useful tool for risk stratification. ACEF score was more suitable for surgical patients in terms of assessing the risk of in-hospital mortality.

Effect of early intrajejunal nutrition on pancreatic pathological features and gut barrier function in dogs with acute pancreatitis.

BACKGROUND: In patients with major trauma and burns, total enteral nutrition (TEN) significantly decreases the acute phase response and incidence of septic complications when compared with total parenteral nutrition (TPN). Traditionally, it was believed that early intrajejunal nutrition (EIN) in severe acute pancreatitis (SAP) may exacerbate the clinical pathological features, lead to recurrence of symptoms and delay complications. OBJECTIVE: To compare the effect of EIN vs TPN on the pancreatic pathological features and gut barrier function in dogs with acute pancreatitis (AP). METHODS: Fifteen dogs (surviving over 7 days, the death rate being 32%, 7/22) were divided into parenteral nutrition (PN) group (n=7) and EIN group (n=8). SAP model was induced by injecting 1 ml/kg of combined solution of 2.5% sodium taurocholate and 8000-10000 BAEE units trypsin/ml into the pancreas via the pancreatic duct. Nutrients were delivered to the EIN group by catheter via a jejunostomy feeding 24 h postoperatively. The two groups were isocaloric and isonitrogenous. Systemic blood samples were obtained before and 1, 4, 7 d following AP, and cultured by aerobic as well as anaerobic bacterial growth. Systemic plasma and portal vein endotoxin levels were quantified by the chromogenic limulus amebocyte lysate (LAL) technique. Portal vein blood and specimens of tissue from mesenteriolum and mesocolon lymph nodes, lung, pulmonary portal lymph nodes and pancreas were adopted before the experiment was finished. Aliquots of the homogenata were cultured as blood mentioned above. Serum glucose, calcium, amylase and lysosomal enzymes were determined. All dogs were injected with 50 microCi (125)I-BSA 4 h at the 7th day before being sacrificed. The (125)I-BSA indexes of the pancreas/muscle and pancreas/blood were measured, and pancreatitic pathological scores (PPSs) of the different partial pancreas were observed. The content of mucosa protein, DNA and the villi, the thickness of mucosa and the whole bowel wall of the ileum and transverse colon were measured. RESULTS: The study showed that serum glucose in the PN group was higher than in the EIN group after SAP 3 d; the levels of systemic plasma endotoxin and the magnitude of bacterial translocation to the portal and systemic blood and distant organ reduced significantly in the EIN group P<0.01. There were no differences between the two groups in the data of serum calcium, amylase and lysosomal enzymes, P>0.05; the (125)I-BSA index of pancreas/muscle and pancreas/blood, and PPS of the head, body, tail and total pancreas did not reach significant difference between the two groups, P>0.05. The contents of protein and DNA, the height of villi, the thickness of mucosa and the whole bowel wall of the ileum and transverse colon in the EIN group were higher than that in the PN group,P <0.01. CONCLUSION: Our results suggested that EIN was safe and effective to be adopted by intrajejunal delivery of nutrients in SAP dogs, did not make SAP clinical pathological features deteriorate, and decreased the occurrence rate of endotoxin and gut bacterial translocation.

[Determination of ciprofloxacin in urine using terbium ion as fluorescent probe].

Factors effecting the fluorescence characteristics of the reaction CPFX-Tb were studied thoroughly. The effect of the experimental conditions on the fluorescence intensity was defined. In the pH 6.0 media, CPFX-Tb complex fluorescence system can emit intrinsic fluorescence of Tb. The excitation and emission wavelengths are 328 nm and 545 nm. The linear range is 1.0 x 10(-8)-1.0 x 10(-6) mol.L-1. The regression equation is F = 1.57 + 4.87 x 10(8) c, r = 0.9999 with the detection limit of 5.0 x 10(-9) mol.L-1. It has been satisfactory for the determination of trace ciprofloxacin in urine by using terbium ion as fluorescent probe.

Biological effects of electric shock and heat denaturation and oxidation of molecules, membranes, and cellular functions.

Direct exposure of cells in suspension to intense electric pulses is known to produce damages to cell membranes and supramolecular organizations of cells, and denaturation of macromolecules, much like injuries and tears seen in electric trauma patients. Thus, the system has been used as a laboratory model for investigating the biochemical basis of electric injury. An intense electric pulse can produce two major effects on cells--one caused by the field, or the electric potential, and the other by current, or the electric energy. The field-induced transmembrane potential can produce electro-conformational changes of ion channels and ion pumps and, when the potential exceeds the dielectric strength of the cell membrane (approximately 500 mV for a pulse width of a few ms), electro-conformational damages and electroporations of membrane proteins and lipid bilayers. These events lead to passage of electric current through the membrane-porated cells and to heating of cell membranes and cytoplasmic contents. The subsequent denaturation of cell membranes and cytoplasmic macromolecules brings about many complex biochemical reactions, including oxidation of proteins and lipids. The combined effects may cripple the cells beyond repair. This communication will focus on the thermal effects of electric shock. After a brief review of the current state of knowledge on thermal denaturation of soluble enzymes and muscle proteins, this paper will describe experiments on the thermal denaturation of cellular components and functions, such as nucleosomes, and the electron transport chain and ATP synthetic enzymes of the mitochondrial inner membranes. Data will show that lipid peroxidation and the subsequent loss of the energy-transducing ability of the cells may occur even at moderate temperatures between 40 degrees C and 45 degrees C. However, lipid peroxidation may be prevented with reducing reagents such as mercaptoethanol, dithiothreitol, and ascorbic acid. Reactivation of denatured cellular proteins and functions may also be possible and a strategy for doing so is discussed.

Least activation path for protein folding: investigation of staphylococcal nuclease folding by stopped-flow circular dichroism.

Is the pathway of protein folding determined by the relative stability of folding intermediates, or by the relative height of the activation barriers leading to these intermediates? This is a fundamental question for resolving the Levinthal paradox, which stated that protein folding by a random search mechanism would require a time too long to be plausible. To answer this question, we have studied the guanidinium chloride (GdmCl)-induced folding/unfolding of staphylococcal nuclease [(SNase, formerly EC 3.1.4.7; now called microbial nuclease or endonuclease, EC 3.1.31.1] by stopped-flow circular dichroism (CD) and differential scanning microcalorimetry (DSC). The data show that while the equilibrium transition is a quasi-two-state process, kinetics in the 2-ms to 500-s time range are triphasic. Data support the sequential mechanism for SNase folding: U3 <--> U2 <--> U1 <--> N0, where U1, U2, and U3 are substates of the unfolded protein and N0 is the native state. Analysis of the relative population of the U1, U2, and U3 species in 2.0 M GdmCl gives delta-G values for the U3 --> U2 reaction of +0.1 kcal/mol and for the U2 --> U1 reaction of -0.49 kcal/mol. The delta-G value for the U1 --> N0 reaction is calculated to be -4.5 kcal/mol from DSC data. The activation energy, enthalpy, and entropy for each kinetic step are also determined. These results allow us to make the following four conclusions. (i) Although the U1, U2, and U3 states are nearly isoenergetic, no random walk occurs among them during the folding. The pathway of folding is unique and sequential. In other words, the relative stability of the folding intermediates does not dictate the folding pathway. Instead, the folding is a descent toward the global free-energy minimum of the native state via the least activation path in the vast energy landscape. Barrier avoidance leads the way, and barrier height limits the rate. Thus, the Levinthal paradox is not applicable to the protein-folding problem. (ii) The main folding reaction (U1 --> N0), in which the peptide chain acquires most of its free energy (via van der Waals' contacts, hydrogen bonding, and electrostatic interactions), is a highly concerted process. These energy-acquiring events take place in a single kinetic phase. (iii) U1 appears to be a compact unfolded species; the rate of conversion of U2 to U1 depends on the viscosity of solution. (iv) All four relaxation times reported here depend on GdmCl concentrations: it is likely that none involve the cis/trans isomerization of prolines. Finally, a mechanism is presented in which formation of sheet-like chain conformations and a hydrophobic condensation event precede the main-chain folding reaction.