The production by monocytes of interleukin-la (IL-la), interleukin-1lj# ), , and tumor necrosis factor alpha (TNFa) in intensive care unit (ICU) patients with sepsis syndrome (n = 23) or noninfectious shock (n = 6) is reported. Plasma cytokines, cell-associated cytokines within freshly isolated monocytes and LPS-induced in vitro cytokine production were assessed at admission and at regular intervals during ICU stay. TNFa and IL-6 were the most frequently detected circulating cytokines. Despite the fact that IL-la is the main cytokine found within monocytes upon in vitro activation of cells from healthy individuals, it was very rarely detected within freshly isolated monocytes from septic patients, and levels of cell-associated IL-1,@ were lower than those of TNFa. Cell-associated IL-1,6 and TNFa were not correlated with corresponding levels in plasma. Upon LPS stimulation, we observed a profound decrease of in vitro IL-la production by monocytes in all patients, and of IL-1if, IL-6, and TNFa in septic patients. This reduced LPS-induced production of cytokines was most pronounced in patients with gram-negative infections. Finally, monocytes from survival patients, but not from nonsurvival ones recovered their capacity to produce normal amounts of cytokines upon LPS stimulation. In conclusion, our data indicate an in vivo activation of circulating monocytes during sepsis as well as in noninfectious shock and suggest that complex regulatory mechanisms can downregulate the production of cytokines by monocytes during severe infections.

The current pathogenic theory of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis and ascites suggests that repeated episodes of bacterial translocation (BT) from intestinal lumen to mesenteric lymph nodes followed by systemic seeding are the key steps for the final development of infectious events. However, most of the episodes of systemic bacterial circulation remain undetected. Therefore, we investigated the hypothetical presence of bacteria in blood and/or ascitic fluid (AF) from patients with cirrhosis and sterile (culture negative) AF by means of bacterial DNA (bactDNA) detection and identification. Twenty-eight consecutively admitted patients with cirrhosis and presence of AF were included in the study. BactDNA was detected using a polymerase chain reaction (PCR)-based method. The corresponding bacteria were identified by nucleotide sequencing of purified PCR products. BactDNA was detected simultaneously in blood and AF in 9 patients (32.1%). DNA sequencing allowed the identification of Escherichia coli (n ‫؍‬ 7) and Staphylococcus aureus (n ‫؍‬ 2). In all cases, the similarity between the sequence found in AF and blood indicated that the bactDNA present in both locations originated from a single clone (single translocation event). Child-Pugh score and basic hemodynamic, clinical, endoscopic, and biochemical characteristics were similar among patients with or without the presence of bactDNA. In conclusion, we have detected bactDNA in serum and AF in 32% of all patients studied, and this likely represents single clone episodes of translocation and systemic seeding. E. coli is the most frequently identified bacteria. (HEPATOLOGY 2002;36:135-141.)

Spine surgery carries an inherent risk of damage to critical neural structures. Intraoperative neurophysiological monitoring (IONM) is frequently used to improve the safety of spine surgery by providing real-time assessment of neural structures at risk. Evidence-based guidelines for safe and efficacious use of IONM are lacking and its use is largely driven by surgeon preference and medicolegal issues. Due to this lack of standardization, the preoperative sign-in serves as a critical opportunity for 3-way discussion between the neurosurgeon, anesthesiologist, and neuromonitoring team regarding the necessity for and goals of IONM in the ensuing case. This analysis contains a review of commonly used IONM modalities including somatosensory evoked potentials, motor evoked potentials, spontaneous or free-running electromyography, triggered electromyography, and combined multimodal IONM. For each modality the methodology, interpretation, and reported sensitivity and specificity for neurological injury are addressed. This is followed by a discussion of important IONM-related issues to include in the preoperative checklist, including anesthetic protocol, warning criteria for possible neurological injury, and consideration of what steps to take in response to a positive alarm. The authors conclude with a cost-effectiveness analysis of IONM, and offer recommendations for IONM use during various forms of spine surgery, including both complex spine and minimally invasive procedures, as well as lower-risk spinal operations.

We tested the hypothesis that the presence of bacterial DNA (bactDNA) in ascitic fluid and serum is associated with decreased survival in patients with cirrhosis. In a prospective, multicenter study, we analyzed the clinical evolution of 156 patients with cirrhosis and ascites (first or recurrence) with lower than 250 polymorphonuclear cells (PMN)/ L, negative ascites bacteriological culture, and absence of other bacterial infections being admitted for evaluation of largevolume paracentesis, according to the presence of bactDNA at admission. Survival, causes of death, and successive hospital admissions were determined during a 12-month follow-up period. BactDNA was detected in 48 patients. The most prevalent identified bactDNA corresponded to Escherichia coli (n ‫؍‬ 32/48 patients, 66.6%). Patients were followed for 12 months after inclusion and in this period 34 patients died: 16 of 108 (15%) From the

Bacterial infections and severity of associated inflammatory reaction influence prognosis in patients with advanced cirrhosis. We compared the innate immune response to bacterial DNA (

Bacterial translocation is currently considered the main pathogenic mechanism leading to spontaneous bacterial peritonitis in patients with advanced cirrhosis and ascites. However, to the authors' knowledge there is no information regarding the characteristics of this process in humans. The goals of the current study were to pursue partially identified bacterial DNA in blood (what the authors consider molecular evidence of bacterial translocation) through its relative quantification in a 72-hour study period by using real-time polymerase chain reaction (PCR). A consecutive series of 17 patients with advanced cirrhosis and culture-negative, nonneutrocytic ascites were studied. Therapeutic paracentesis was performed at the time of admission, and blood samples were obtained at baseline and every 8 hours in a 3-day period. S pontaneous bacterial peritonitis (SBP) is a severe infection developing in patients with advanced cirrhosis, in the absence of any intraabdominal, surgically treatable source of infection. 1 It is considered to be the final consequence of repeated episodes of bacterial translocation (BT) from the intestinal lumen and eventual arrival of bacteria in the ascitic fluid (AF). However, the predisposition to develop a SBP episode is related to its intrinsic bactericidal properties. [2][3][4] BT is an incompletely understood process by which intestinal bacteria can cross the epithelial wall, thereby reaching mesenteric lymph nodes and other organs. 5 BT has been studied extensively in cirrhotic rats, 6,7 but for obvious reasons it is difficult to study its incidence in patients with cirrhosis. 8 We recently reported the presence of bacterial DNA (BactDNA) in blood and AF in roughly 40% of patients with cirrhosis and culture-negative, nonneutrocytic ascites 9 and, although more experimental work is needed to confirm our hypothesis, the data available to date may represent molecular evidence of BT. This method allows the study of BT in patients without clinical evidence of infection, thus becoming a useful tool with which to investigate the steps preceding a fully developed infection.To our knowledge, to date it is not known whether bacteria translocate as the result of a "single pulse" event or, conversely, bacteria continuously are crossing the intestinal wall, and what is the rate of bacterial clearance from the systemic circulation. Although we previously reported that Escherichia coli is the most prevalent bacteria found to cause episodes of BT at the time of admission, 9 we do not know whether this finding may be different in the following hours or days.Therefore, the objectives of the current investigation were to explore the temporal pattern of BactDNA clear-

Background and aims: Translocation of intestinal bacteria to ascitic fluid is probably the first step in the development of episodes of spontaneous bacterial peritonitis in patients with cirrhosis. We have recently reported the detection of bacterial DNA in blood and ascitic fluid from patients with advanced cirrhosis, what we consider as molecular evidence of bacterial translocation. Several studies have shown the immunogenic role of bacterial DNA in vitro, and we hypothesised that the presence of bacterial DNA could activate the type I immune response in peritoneal macrophages from these patients, leading to greater cytokine synthesis (interleukin (IL)-2 and IL-12, tumour necrosis factor a, and interferon c) and effector molecules such as nitric oxide. Methods: Peritoneal macrophages obtained from patients with cirrhosis and culture negative nonneutrocytic ascitic fluid were collected and characterised by flow cytometry. Inducible nitric oxide synthase, nitric oxide levels, and cytokine production were measured by immunoenzymometric assays in basal and harvested conditions according to the presence/absence of bacterial DNA. Results: The ability of peritoneal macrophages to synthesise nitric oxide and levels of all cytokines were significantly increased in patients with bacterial DNA. There was a positive correlation between inducible nitric oxide synthase and nitric oxide levels. Conclusions: The presence of bacterial DNA in patients with decompensated cirrhosis is associated with marked activation of peritoneal macrophages, as evidenced by nitric oxide synthesising ability, together with enhanced cytokine production.

We report our investigations of circulating interleukin (IL) 1 beta, IL 6 and tumor necrosis factor (TNF)-alpha, as well as cell-associated IL 1 alpha, IL 1 beta and TNF-alpha in plasma and monocytes of 21 patients with sepsis syndrome and 6 patients with non-septic shock. Longitudinal studies reveal that (a) the most frequent detectable plasma cytokines were TNF-alpha and IL 6, (b) the presence and the kinetics of circulating cytokines were independent of one other, (c) detectable levels of cytokines could be found for a long period of time, and (d) significantly higher levels of IL 6 were found for non-surviving patients. Because of the in vivo half-life of cytokines and of the existence of numerous specific high-affinity receptors, it is quite probable that detectable plasma cytokines represent the excess of produced mediators which have not been trapped by the target cells. TNF-alpha (410 +/- 65 pg/10(6) monocytes) and IL 1 beta (153 +/- 60 pg/10(6) monocytes) were frequently found associated to monocyte lysates (88% and 50%, respectively). Despite the fact that IL 1 alpha is the most abundant cytokine found associated to monocytes following in vitro activation, IL 1 alpha was rarely found in monocytes of intensive care unit patients (29%). No correlation was found to exist between the levels of plasma cytokines and cell-associated cytokines. Some patients had plasma TNF-alpha or IL 1 beta in the absence of the corresponding monocyte-associated cytokine. This observation suggests that cells other than monocytes can participate in the production of circulating cytokines. At the end of the longitudinal study (day 14 +/- 2), only 2/12 surviving patients still had plasma TNF-alpha, whereas 8/12 had monocyte-associated TNF-alpha. These results indicate that activation of monocytes still occurs in patients for whom no plasma cytokines can be detected. Thus, in addition to the measurement of plasma cytokine, measurement of cell-associated cytokine appears useful to assess cytokine production and monocyte activation in vivo.