Nitric oxide production by human peripheral blood mononuclear cells.

INTRODUCTION: There are conflicting data on the ability of human mononuclear cells to produce nitric oxide (NO). We investigated nitric oxide production from peripheral blood mononuclear cells (PBMs) by using a new sensitive fluorescent indicator. MATERIALS AND METHODS: PBMs from healthy volunteers were collected, plated in 96-well microplates, and loaded with the fluorescent nitric oxide probe, 4,5-diaminofluorescein diacetate (DAF-2DA). Experiments were performed in normal control and endotoxin-stimulated PBMs, with and without exogenous L-arginine. The exogenous nitric oxide donor S-nitroso-N-acetyl-penicillamine (SNAP) was used as a positive control. Fluorescence intensity was measured with a fluorescence microplate reader. RESULTS: Nitric oxide production by human PBMs can be demonstrated by the use of the fluorescent indicator, DAF-2DA, in both control and endotoxin-stimulated conditions. Nitric oxide production was independent of the concentration of exogenous L-arginine. The addition of endotoxin did not change nitric oxide production. PBMs treated with SNAP showed a concentration dependent increase in fluorescence. Nitric oxide production over 5 hours was constant and identical in both control and stimulated groups. CONCLUSION: This fluorescent indicator technique is useful for the study of NO production by human PBMs. Nitric oxide production by PBMs was independent of exogenous L-arginine concentration and was not affected by endotoxin

Predicted Factors of Prolonged Postoperative ICU Admission More Than Four Days: Thai Tertiary University Hospital

Objective: To identify the risk factors associated with prolonged intensive care unit admission (≥4 days) and mortalityinpostoperative surgicalpatients. Methods: A retrospective, case-control study was conductedin527patients admittedtopostoperative intensive care units during a 1-year period. Fifteen factors were included in univariate and only significant factors were includedin multivariate analyses. Results: Twenty one percent of all admissions had prolonged length-of-stay. From multivariate analysis, predictedriskfactorswereemergencysurgery(OR 2.9,p=0.001, CI1.6-5.2); remainedintubation(OR 2.6,p=0.007, CI 1.3-5.4), unplanned ICU admission (OR 2.1, p=0.03, CI 1.1-4.2); SAPS II score >52 (OR 4.8, p<0.001, CI 2.5-9.2),SAPSII score>64 (OR 6.1, p<0.001, CI 2.7-13.8) and inotrope infusion in ICU (OR 4.5, p<0.001, CI 2.5-8) which were associated with prolonged ICU admission. Factors associated with ICU mortality (10.06%) were; ASA physical status >3 (OR 8.2, p=0.003, CI 2-32.9), ICU readmission (OR 3.9, p=0.007, CI 1.5-10.8), inotrope infusion inICU (OR 3, p=0.006, CI1.4-6.7), renal replacement therapy (OR 3.2, p=0.007, CI 1.3-8.2), SAPSII score52-63(OR 3.6,p=0.018, CI1.2-6.8),SAPSII score>64(OR 3.9,p=0.006, CI1.4-9) andcirrhosis (OR 4.9,p=0.04, CI1.1-21). Conclusion: ASA physicalstatus>3andSAPSIIscore>52 wereindependentpredictivefactorsofbothprolonged intensive careunit admissionand mortality

Performance of diamino fluorophores for the localization of sources and targets of nitric oxide

An emergent approach to the detection of nitric oxide (NO) in tissues relies on the use of fluorescence probes that are activated by products of NO autoxidation. Here we explore the performance of the widely used NO probe 4,5-diaminofluorescein diacetate (DAF-2 DA) for the localization of sources of NO in rat aortic tissue, either from endogenous NO synthesis or from chemically or photolytically released NO from targets of nitrosation/nitrosylation. Of importance toward understanding the performance of this probe in tissues is the finding that, with incubation conditions commonly used in the literature (10 microM DAF-2 DA), intracellular DAF-2 accumulates to concentrations that approach the millimolar range. Whereas such high probe concentrations do not interfere with NO release or signaling, they help to clarify why DAF-2 nitrosation is possible in the presence of endogenous nitrosation scavengers (e.g., ascorbate and glutathione). The gain attained with such elevated concentrations is, however, mitigated by associated high levels of background autofluorescence from the probe. This, together with tissue autofluorescence, limits the sensitivity of the probe to low-micromolar levels of accumulated DAF-2 triazole (DAF-2 T), the activated form of the probe, which is higher than the concentrations of most endogenous nitrosation/nitrosylation products found in tissues. We further show that the compartmentalization of DAF-2 around elastic fibers further limits its potential to characterize the site of NO production at the subcellular level. Moreover, we find that reaction of DAF-2 with HgCl(2) and other commonly employed reagents is associated with spectral changes that may be misinterpreted as NO signals. Finally, UV illumination can lead to high levels of nitrosating species that interfere with NO detection from enzymatic sources. These findings indicate that while DAF-2 may still represent an important tool for the localization of NO synthesis, provided important pitfalls and limitations are taken into consideration, it is not suited for the detection of basally generated nitrosation/nitrosylation products

Candida bloodstream infections in intensive care units: analysis of the extended prevalence of infection in intensive care unit study

To provide a global, up-to-date picture of the prevalence, treatment, and outcomes of Candida bloodstream infections in intensive care unit patients and compare Candida with bacterial bloodstream infection. DESIGN: A retrospective analysis of the Extended Prevalence of Infection in the ICU Study (EPIC II). Demographic, physiological, infection-related and therapeutic data were collected. Patients were grouped as having Candida, Gram-positive, Gram-negative, and combined Candida/bacterial bloodstream infection. Outcome data were assessed at intensive care unit and hospital discharge. SETTING: EPIC II included 1265 intensive care units in 76 countries. PATIENTS: Patients in participating intensive care units on study day. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of the 14,414 patients in EPIC II, 99 patients had Candida bloodstream infections for a prevalence of 6.9 per 1000 patients. Sixty-one patients had candidemia alone and 38 patients had combined bloodstream infections. Candida albicans (n = 70) was the predominant species. Primary therapy included monotherapy with fluconazole (n = 39), caspofungin (n = 16), and a polyene-based product (n = 12). Combination therapy was infrequently used (n = 10). Compared with patients with Gram-positive (n = 420) and Gram-negative (n = 264) bloodstream infections, patients with candidemia were more likely to have solid tumors (p < .05) and appeared to have been in an intensive care unit longer (14 days [range, 5-25 days], 8 days [range, 3-20 days], and 10 days [range, 2-23 days], respectively), but this difference was not statistically significant. Severity of illness and organ dysfunction scores were similar between groups. Patients with Candida bloodstream infections, compared with patients with Gram-positive and Gram-negative bloodstream infections, had the greatest crude intensive care unit mortality rates (42.6%, 25.3%, and 29.1%, respectively) and longer intensive care unit lengths of stay (median [interquartile range]) (33 days [18-44], 20 days [9-43], and 21 days [8-46], respectively); however, these differences were not statistically significant. CONCLUSION: Candidemia remains a significant problem in intensive care units patients. In the EPIC II population, Candida albicans was the most common organism and fluconazole remained the predominant antifungal agent used. Candida bloodstream infections are associated with high intensive care unit and hospital mortality rates and resource use