Foodborne botulism, a forgotten yet life-threatening disease: a case report

OBJECTIVE

Botulism is a very rare disease in Switzerland, with less than one case per year, an incidence of 0.01 cases for 100,000 inhabitants. Indeed, over the past ten years, 9 cases have been reported to Public Health registry. Foodborne botulism (FB) is caused by ingestion of preformed botulinum neurotoxin. Characteristic features should be rapidly recognized, and prompt treatment should be administered to avoid further progression towards respiratory failure and death.

CASE REPORT

We report the case of a patient who developed gastrointestinal symptoms just after a sandwich consumption followed by rapidly progressive cranial nerve impairment, truncal muscle weakness in a descending pattern and respiratory failure requiring mechanical ventilation. The diagnosis of foodborne botulism was delayed due to differential diagnosis considerations. Specific antitoxin therapy was administered immediately after firm clinical conviction of botulism, without waiting for serologic results that later confirmed the diagnosis. As expected, muscle weakness recovery was slow, with persistent chronic deficits nine years later.

CONCLUSIONS

This case highlights differential diagnosis issues of botulism. These include acute neuromuscular disorders such as myasthenia gravis, Guillain-Barré syndrome, or tick-borne encephalitis. The importance of careful medical history and repeated clinical evaluation to avoid misdiagnosis can be lifesaving. Our case highlights the typical warning signs.

SRChing for the substrates of Src

By the mid 1980's, it was clear that the transforming activity of oncogenic Src was linked to the activity of its tyrosine kinase domain and attention turned to identifying substrates, the putative next level of control in the pathway to transformation. Among the first to recognize the potential of phosphotyrosine-specific antibodies, Parsons and colleagues launched a risky shotgun-based approach that led ultimately to the cDNA cloning and functional characterization of many of today's best-known Src substrates (for example, p85-Cortactin, p110-AFAP1, p130Cas, p125FAK and p120-catenin). Two decades and over 6000 citations later, the original goals of the project may be seen as secondary to the enormous impact of these protein substrates in many areas of biology. At the request of the editors, this review is not restricted to the current status of the substrates, but reflects also on the anatomy of the project itself and some of the challenges and decisions encountered along the way.

[Pulmonary metastatic calcification]

INTRODUCTION

The lung is the organ most frequently involved by metastatic calcification. This condition is probably under-diagnosed, the patients usually being asymptomatic. This article summarizes the current knowledge concerning pulmonary metastatic calcification.

BACKGROUND

The pathogenesis of pulmonary metastatic calcification is not well known, but it involves phosphate-calcium balance, renal function and pH. The most frequently encountered aetiologies are hyperparathyroidism, neoplastic bony lesions, and renal failure. The definitive diagnosis is achieved by histology, radiological examinations being insensitive. The clinical manifestations are various and can include a pulmonary restrictive syndrome, diffusion abnormalities, hypoxaemia and respiratory failure. The latter can be severe and influence the prognosis adversely: 19 cases of fatal pulmonary metastatic calcification have been reported. The treatment is aetiological and symptomatic.

VIEWPOINT

The prognostic factors for a poor outcome of this potentially lethal condition remain to be determined. The management of asymptomatic patients is also uncertain.

CONCLUSIONS

Pulmonary metastatic calcification is a rare condition of complex pathogenesis. The clinical manifestations are varied, ranging from asymptomatic to severe, even fatal.

Thymoma, immunodeficiency, and herpes simplex virus infections

Hypogammaglobulinemia develops in 3 to 6% of patients with thymoma and this association is commonly referred to as thymoma with immunodeficiency (formerly Good syndrome). Recurrent infections with encapsulated bacteria and opportunistic infections associated with disorders of both humoral and cell mediated immunity frequently occur in this rare primary, adult-onset immunodeficiency. We report a case of thymoma with immunodeficiency complicated by disseminated herpes simplex virus (HSV) infection and review five additional cases of HSV-related infections reported since 1966 in patients presenting with thymoma with immunodeficiency. Patients presented with epiglottitis, keratitis, recurrent genital herpes, ulcerative dermatitis, and acute hepatitis. Four of the six cases had a fatal outcome, two of which were directly attributable to HSV infection. Since the risk of invasive opportunistic infections is high and the presentation atypical, lymphocyte count and total serum immunoglobulin should be measured regularly in all patients presenting with thymoma with immunodeficiency.

Status epilepticus: An independent outcome predictor after cerebral anoxia

BACKGROUND

Prognosis of status epilepticus (SE) depends on its cause, but there is uncertainty as to whether SE represents an independent outcome predictor for a given etiology. Cerebral anoxia is a relatively homogenous severe encephalopathy. Postanoxic SE is associated to a nearly 100% mortality in this setting; however, it is still unclear whether this is a severity marker of the underlying encephalopathy, or an independent factor influencing outcome. The goal of this study was to assess if postanoxic SE is independently associated with mortality after cerebral anoxia.

METHODS

This was a retrospective observation of consecutive comatose survivors of cardiac arrest, including subjects treated with hypothermia. On the subgroup with EEG recordings in the first hospitalization days, univariate and multivariate analyses were applied to potential determinants of in-hospital mortality, and included the following variables: age, gender, type and length of cardiac arrest, occurrence of circulatory shock, presence of therapeutic hypothermia, and electrographic SE.

RESULTS

Out of 166 postanoxic patients, 107 (64%) had an EEG (median latency from admission, 2 days); in this group, therapeutic hypothermia was administered in 59%. Death occurred in 71 (67%) patients. Postanoxic SE was associated with mortality regardless of type of acute cardiac rhythm and administration of hypothermic treatment.

CONCLUSION

In this hospital-based cohort, postanoxic status epilepticus (SE) seems to be independently related to death in cardiac arrest survivors, suggesting that SE might determine a bad prognosis for a given etiology. Confirmation of these results in a prospective assessment is needed.

[Merging of two intensive care units: preliminary observations]

The merging of two intensive care units is a time of profound change, and constitutes a risk of mishaps. We report some aspects of such a project in our institution. The evaluation of various indicators reflecting the activity, patient's hospital pathways, mortality, as well as the use of specific techniques, has shown that no particular problem was observed during the first 9 months. Improvements in performance or productivity have not been demonstrated so far. The follow-up will permit to demonstrate long-term benefits. We believe that these observations may be of interest for other departmental or hospital reorganisations.

[Spirituality in critical care]

Taking care of a critically-ill patient is of high complexity level, as it includes bio-pschosocial and cultural aspects. Until recently, physicians have paid little attention to spirituality, although it constitutes the essential of human being. Spiritual need may reveal to be of utmost importance and has influence on bio-psycho-social aspects for a patient experiencing severe disease with threatening outcome and near death. A physician may transfer the problem to a specialist, a chaplain, or may personally be able to assess this need. To put a bio-psycho-social-spiritual model of care into practice, health care givers including chaplains should set up a team work. Their educational programs should include spirituality care training. Swiss intensivists should acquire the competency to take care of their patients in a holistic manner.

Cefepime versus imipenem-cilastatin for treatment of nosocomial pneumonia in intensive care unit patients: a multicenter, evaluator-blind, prospective, randomized study

In a randomized, evaluator-blind, multicenter trial, we compared cefepime (2 g three times a day) with imipenem-cilastatin (500 mg four times a day) for the treatment of nosocomial pneumonia in 281 intensive care unit patients from 13 centers in six European countries. Of 209 patients eligible for per-protocol analysis of efficacy, favorable clinical responses were achieved in 76 of 108 (70%) patients treated with cefepime and 75 of 101 (74%) patients treated with imipenem-cilastatin. The 95% confidence interval (CI) for the difference between these response rates (-16 to 8%) failed to exclude the predefined lower limit for noninferiority of -15%. In addition, therapy of pneumonia caused by an organism producing an extended-spectrum beta-lactamase (ESBL) failed in 4 of 13 patients in the cefepime group but in none of 10 patients in the imipenem group. However, the clinical efficacies of both treatments appeared to be similar in a secondary intent-to-treat analysis (95% CI for difference, -9 to 14%) and a multivariate analysis (95% CI for odds ratio, 0.47 to 1.75). Furthermore, the all-cause 30-day mortality rates were 28 of 108 (26%) patients in the cefepime group and 19 of 101 (19%) patients in the imipenem group (P = 0.25). Rates of documented or presumed microbiological eradication of the causative organism were similar with cefepime (61%) and imipenem-cilastatin (54%) (95% CI, -23 to 8%). Primary or secondary resistance of Pseudomonas aeruginosa was detected in 19% of the patients treated with cefepime and 44% of the patients treated with imipenem-cilastatin (P = 0.05). Adverse events were reported in 71 of 138 (51%) and 62 of 141 (44%) patients eligible for safety analysis in the cefepime and imipenem groups, respectively (P = 0.23). Although the primary end point for this study does not exclude the possibility that cefepime was inferior to imipenem, some secondary analyses showed that the two regimens had comparable clinical and microbiological efficacies. Cefepime appeared to be less active against organisms producing an ESBL, but primary and secondary resistance to imipenem was more common for P. aeruginosa. Selection of a single agent for therapy of nosocomial pneumonia should be guided by local resistance patterns.

Pharmacokinetics and dosage adaptation of meropenem during continuous venovenous hemodiafiltration in critically ill patients

Meropenem, a carbapenem broad-spectrum antibiotic, is regularly used in patients undergoing continuous venovenous hemodiafiltration (CVVHDF). Its disposition was studied over one dosage interval in 15 patients under CVVHDF on a steady regimen of 500 or 1000 mg every 8 to 12 hours. Meropenem levels were measured in plasma and filtrate-dialysate by high-performance liquid chromatography (HPLC) with UV detection. The mean CVVHDF flow rates were 7.1 +/- 0.9 L/h for blood (mean +/- SD), 0.5 +/- 0.3 L/h for predilution solution, 1.2 +/- 0.3 L/h for countercurrent dialysate, and 1.8 +/- 0.5 L/h for the total filtrate-dialysate. The pharmacokinetic analysis was based both on a noncompartmental approach and on a four-compartment modeling. The mean (coefficient of variation [CV]) total body clearance, volume of distribution at steady state, and mean residence time were, respectively, 5.0 L/h (46%), 14.3 L (29%), and 4.8 h (36%). The hemodiafiltration clearances calculated from plasma data alone and plasma with filtrate-dialysate data were 1.2 L/h (26%) and 1.6 L/h (39%), respectively. The compartmental model was used to optimize the therapeutic schedule of meropenem, considering reference minimal inhibitory concentration (MIC) of sensitive strains (4 mg/L). The results indicate that two different therapeutic schedules of meropenem are equally applicable to patients receiving CVVHD: either 750 mg tid or 1500 bid.

Intrapericardial urokinase irrigation and systemic corticosteroids: an alternative to pericardectomy for persistent fibrino-purulent pericarditis

A 39-year-old man was admitted for upper abdominal pain and shortness of breath. The chest roentgenogram demonstrated cardiomegaly and left lower lobe atelectasis. Echocardiography showed circumferential pericardial effusion with signs of cardiac tamponade. Pericardial biopsy and fluid analysis were consistent with fibrino-purulent pericarditis. Despite broad-spectrum antibiotics, percutaneous and subsequently surgical drainage, pericardial effusion and tamponade recurred. We report successful treatment of a non-resolving fibrino-purulent pericardial effusion by combined intrapericardial irrigation of fibrinolytics and systemic corticosteroids administration as an alternative to pericardectomy.

Determination of meropenem in plasma and filtrate-dialysate from patients under continuous veno-venous haemodiafiltration by SPE-LC

Meropenem, a carbapenem antibiotic displaying a broad spectrum of antibacterial activity, is administered in Medical Intensive Care Unit to critically ill patients undergoing continuous veno-venous haemodiafiltration (CVVHDF). However, there are limited data available to substantial rational dosing decisions in this condition. In an attempt to refine our knowledge and propose a rationally designed dosage regimen, we have developed a HPLC method to determine meropenem after solid-phase extraction (SPE) of plasma and dialysate fluids obtained from patients under CVVHDF. The assay comprises the simultaneous measurement of meropenem's open-ring metabolite UK-1a, whose fate has never been studied in CVVHDF patients. The clean-up procedure involved a SPE on C18 cartridge. Matrix components were eliminated with phosphate buffer pH 7.4 followed by 15:85 MeOH-phosphate buffer pH 7.4. Meropenem and UK-1a were subsequently desorbed with MeOH. The eluates were evaporated under nitrogen at room temperature (RT) and reconstituted in phosphate buffer pH 7.4. Separation was performed at RT on a Nucleosil 100-5 microm C18 AB cartridge column (125 x 4 mm I.D.) equipped with a guard column (8 x 4 mm I.D.) with UV-DAD detection set at 208 nm. The mobile phase was 1 ml min(-1), using a step-wise gradient elution program: %MeOH/0.005 M tetrabutylammonium chloride pH 7.4; 10/90-50/50 in 27 min. Over the range of 5-100 microg ml(-1), the regression coefficient of the calibration curves (plasma and dialysate) were >0.998. The absolute extraction recoveries of meropenem and UK-1a in plasma and filtrate-dialysate were stable and ranged from 88-93 to 72-77% for meropenem, and from 95-104 to 75-82% for UK-1a. In plasma and filtrate-dialysate, respectively, the mean intra-assay precision was 4.1 and 2.6% for meropenem and 4.2 and 3.7% for UK-1a. The inter-assay variability was 2.8 and 3.6% for meropenem and 2.3 and 2.8% for UK-1a. The accuracy was satisfactory for both meropenem and UK-1a with deviation never exceeding 9.0% of the nominal concentrations. The stability of meropenem, studied in biological samples left at RT and at +4 degrees C, was satisfactory with < 5% degradation after 1.5 h in blood but reached 22% in filtrate-dialysate samples stored at RT for 8 h, precluding accurate measurements of meropenem excreted unchanged in the filtrate-dialysate left at RT during the CVVHDF procedure. The method reported here enables accurate measurements of meropenem in critically ill patients under CVVHDF, making dosage individualisation possible in such patients. The levels of the metabolite UK-1a encountered in this population of patients were higher than those observed in healthy volunteers but was similar to those observed in patients with renal impairment under hemodialysis.

The protein tyrosine phosphatase-PEST is implicated in the negative regulation of epidermal growth factor on PRL signaling in mammary epithelial cells

Treatment of HC11 mammary epithelial cells with the lactogenic hormone PRL promotes differentiation and induction of milk protein gene expression via stimulation of the Janus kinase (JAK)/signal transducer and activator of transcription pathway. We have previously shown that autocrine activation of epidermal growth factor (EGF) receptor interferes with normal PRL-induced differentiation. Here we show that PRL activation of JAK2 was dramatically reduced in HC11 cells pretreated with EGF, demonstrating that the target of EGF receptor activation is JAK2 kinase. Using an in-gel protein tyrosine phosphatase (PTP) assay, we observed that the activity of a 125-kDa PTP was up-regulated in HC11 cells in response to EGF. A specific antiserum was used to demonstrate that the 125-kDa PTP was PTP-PEST and to show that EGF treatment of HC11 cells led to an increase in the level of PTP-PEST. In intact HC11 cells, PTP-PEST was constitutively associated with JAK2, and in response to EGF treatment there was an increased level of PTP-PEST in JAK2 complexes. An in vitro phosphatase assay, using PRL-activated JAK2 as the substrate and lysates from HC11 cells as the source of PTP-PEST, revealed that JAK2 could serve as a PTP-PEST substrate. However, in intact cells the regulation of JAK2 by PTP-PEST was complex, since transient overexpression of PTP-PEST had a negligible effect on PRL-induced JAK2 activation. EGF's negative influence on JAK2 activity was blocked by actinomycin D treatment of HC11 cells, suggesting that EGF induced a protein that mediated the effects of PTP-PEST on JAK2. In support of this model, PTP-PEST-containing lysates from EGF-treated HC11 cells dephosphorylated JAK2 to a greater extent than lysates prepared from control cells.

Multiple stimuli induce tyrosine phosphorylation of the Crk-binding sites of paxillin

Paxillin is a focal-adhesion-associated, tyrosine-phosphorylated protein. In cells transformed by the src, crk or BCR-Abl oncogenes, the phosphotyrosine content of paxillin is elevated. In normal cells paxillin functions in signalling following integrin-dependent cell adhesion or exposure to a number of stimuli, including growth factors and neuropeptides. These stimuli induce tyrosine phosphorylation of paxillin, regulating the association of Src homology 2 domain-containing signalling molecules with paxillin. There are multiple sites of tyrosine phosphorylation on paxillin. To elucidate the role of paxillin in transducing signals in response to various stimuli, it is essential to identify all of the sites of phosphorylation on paxillin and to define which residues are phosphorylated in response to distinct stimuli. We describe two new sites of tyrosine phosphorylation on paxillin, residues at positions 40 and 88. Using paxillin variants with phenylalanine substitutions at phosphorylation sites and phospho-specific paxillin antibodies, tyrosine phosphorylation of paxillin in response to distinct stimuli was examined. The results demonstrate that Tyr(31) and Tyr(118), which are binding sites for Crk, are major sites of tyrosine phosphorylation following cell adhesion or stimulation with platelet-derived growth factor or angiotensin II. Thus multiple stimuli may elicit similar signalling events downstream of paxillin.

Paxillin: a focal adhesion-associated adaptor protein

Paxillin is a focal adhesion-associated, phosphotyrosine-containing protein that may play a role in several signaling pathways. Paxillin contains a number of motifs that mediate protein-protein interactions, including LD motifs, LIM domains, an SH3 domain-binding site and SH2 domain-binding sites. These motifs serve as docking sites for cytoskeletal proteins, tyrosine kinases, serine/threonine kinases, GTPase activating proteins and other adaptor proteins that recruit additional enzymes into complex with paxillin. Thus paxillin itself serves as a docking protein to recruit signaling molecules to a specific cellular compartment, the focal adhesions, and/or to recruit specific combinations of signaling molecules into a complex to coordinate downstream signaling. The biological function of paxillin coordinated signaling is likely to regulate cell spreading and motility.

Protective effects of hypercapnic acidosis on ventilator-induced lung injury

To investigate whether respiratory acidosis modulates ventilator-induced lung injury (VILI), we perfused (constant flow) 21 isolated sets of normal rabbit lungs, ventilated them for 20 min (pressure controlled ventilation [PCV] = 15 cm H(2)O) (Baseline) with an inspired CO(2) fraction adjusted for the partial pressure of CO(2) in the perfusate (PCO(2) approximately equal to 40 mm Hg), and then randomized them into three groups. Group A (control: n = 7) was ventilated with PCV = 15 cm H(2)O for three consecutive 20-min periods (T1, T2, T3). In Group B (high PCV/normocapnia; n = 7), PCV was given at 20 (T1), 25 (T2), and 30 (T3) cm H(2)O. The targeted PCO(2) was 40 mm Hg in Groups A and B. Group C (high PCV/hypercapnia; n = 7) was ventilated in the same way as Group B, but the targeted PCO(2) was approximately equal to 70 to 100 mm Hg. The changes (from Baseline to T3) in weight gain (Delta WG: g) and in the ultrafiltration coefficient (Delta K(f) = gr/min/ cm H(2)O/100g) and the protein and hemoglobin concentrations in bronchoalveolar lavage fluid (BALF) were used to assess injury. Group B experienced a significantly greater Delta WG (14.85 +/- 5.49 [mean +/- SEM] g) and Delta K(f) (1.40 +/- 0.49 g/min/cm H(2)O/100 g) than did either Group A (Delta WG = 0.70 +/- 0.43; Delta K(f) = 0.01 +/- 0.03) or Group C (Delta WG = 5.27 +/- 2.03 g; Delta K(f) = 0.25 +/- 0.12 g/min/cm H(2)O/ 100 g). BALF protein and hemoglobin concentrations (g/L) were higher in Group B (11.98 +/- 3.78 g/L and 1.82 +/- 0.40 g/L, respectively) than in Group A (2.92 +/- 0.75 g/L and 0.38 +/- 0.15 g/L) or Group C (5.71 +/- 1.88 g/L and 1.19 +/- 0.32 g/L). We conclude that respiratory acidosis decreases the severity of VILI in this model.

Biochemical signals and biological responses elicited by the focal adhesion kinase

The focal adhesion kinase, FAK, is an important component of an integrin-dependent signaling pathway, which functions to transmit signals from the extracellular matrix into the cytoplasm. FAK is an essential gene product, since the fak-/- mouse exhibits embryonic lethality. A number of important biological processes, including cell motility and cell survival, are controlled by integrin-dependent signals and FAK has been implicated in regulating these processes. This review will focus upon recent findings providing insight into the mechanisms by which FAK transmits biochemical signals and elicits biological effects.

Inhibition of the catalytic activity of cell adhesion kinase beta by protein-tyrosine phosphatase-PEST-mediated dephosphorylation

Protein-tyrosine phosphatase (PTP)-PEST is a cytoplasmic tyrosine phosphatase that can bind and dephosphorylate the focal adhesion-associated proteins p130(CAS) and paxillin. Focal adhesion kinase (FAK) and cell adhesion kinase beta (CAKbeta)/PYK2/CADTK/RAFTK are protein-tyrosine kinases that can colocalize with, bind to, and induce tyrosine phosphorylation of p130(CAS) and paxillin. Thus, we considered the possibility that these kinases might be substrates for PTP-PEST. Using a combination of substrate-trapping assays and overexpression of PTP-PEST in mammalian cells, CAKbeta was found to be a substrate for PTP-PEST. Both the major autophosphorylation site of CAKbeta (Tyr(402)) and activation loop tyrosine residues, Tyr(579) and Tyr(580), were targeted for dephosphorylation by PTP-PEST. Dephosphorylation of CAKbeta by PTP-PEST dramatically inhibited CAKbeta kinase activity. In contrast, FAK was a poor substrate for PTP-PEST, and treatment with PTP-PEST had no effect on FAK kinase activity. Tyrosine phosphorylation of paxillin, which is greatly enhanced by CAKbeta overexpression, was dramatically reduced upon coexpression of PTP-PEST. Finally, endogenous PTP-PEST and endogenous CAKbeta were found to localize to similar cellular compartments in epithelial and smooth muscle cells. These results suggest that CAKbeta is a substrate of PTP-PEST and that FAK is a poor PTP-PEST substrate. Further, PTP-PEST can negatively regulate CAKbeta signaling by inhibiting the catalytic activity of the kinase.

CD14 expression on monocytes and TNF alpha production in patients with septic shock, cardiogenic shock or bacterial pneumonia

OBJECTIVES

In patients with septic shock, circulating monocytes become refractory to stimulation with microbial products. Whether this hyporesponsive state is induced by infection or is related to shock is unknown. To address this question, we measured TNF alpha production by monocytes or by whole blood obtained from healthy volunteers (controls), from patients with septic shock, from patients with severe infection (bacterial pneumonia) without shock, and from patients with cardiogenic shock without infection.

MEASUREMENTS

The numbers of circulating monocytes, of CD14+ monocytes, and the expression of monocyte CD14 and the LPS receptor, were assessed by flow cytometry. Monocytes or whole blood were stimulated with lipopolysaccharide endotoxin (LPS), heat-killed Escherichia coli or Staphylococcus aureus, and TNF alpha production was measured by bioassay.

RESULTS

The number of circulating monocytes, of CD14+ monocytes, and the monocyte CD14 expression were significantly lower in patients with septic shock than in controls, in patients with bacterial pneumonia or in those with cardiogenic shock (p < 0.001). Monocytes or whole blood of patients with septic shock exhibited a profound deficiency of TNF alpha production in response to all stimuli (p < 0.05 compared to controls). Whole blood of patients with cardiogenic shock also exhibited this defect (p < 0.05 compared to controls), although to a lesser extent, despite normal monocyte counts and normal CD14 expression.

CONCLUSIONS

Unlike patients with bacterial pneumonia, patients with septic or cardiogenic shock display profoundly defective TNF alpha production in response to a broad range of infectious stimuli. Thus, down-regulation of cytokine production appears to occur in patients with systemic, but not localised, albeit severe, infections and also in patients with non-infectious circulatory failure. Whilst depletion of monocytes and reduced monocyte CD14 expression are likely to be critical components of the hyporesponsiveness observed in patients with septic shock, other as yet unidentified factors are at work in this group and in patients with cardiogenic shock.

CD14 expression on monocytes and TNF alpha production in patients with septic shock, cardiogenic shock or bacterial pneumonia

OBJECTIVES

In patients with septic shock, circulating monocytes become refractory to stimulation with microbial products. Whether this hyporesponsive state is induced by infection or is related to shock is unknown. To address this question, we measured TNF alpha production by monocytes or by whole blood obtained from healthy volunteers (controls), from patients with septic shock, from patients with severe infection (bacterial pneumonia) without shock, and from patients with cardiogenic shock without infection.

MEASUREMENTS

The numbers of circulating monocytes, of CD14+ monocytes, and the expression of monocyte CD14 and the LPS receptor, were assessed by flow cytometry. Monocytes or whole blood were stimulated with lipopolysaccharide endotoxin (LPS), heat-killed Escherichia coli or Staphylococcus aureus, and TNF alpha production was measured by bioassay.

RESULTS

The number of circulating monocytes, of CD14+ monocytes, and the monocyte CD14 expression were significantly lower in patients with septic shock than in controls, in patients with bacterial pneumonia or in those with cardiogenic shock (p < 0.001). Monocytes or whole blood of patients with septic shock exhibited a profound deficiency of TNF alpha production in response to all stimuli (p < 0.05 compared to controls). Whole blood of patients with cardiogenic shock also exhibited this defect (p < 0.05 compared to controls), although to a lesser extent, despite normal monocyte counts and normal CD14 expression.

CONCLUSIONS

Unlike patients with bacterial pneumonia, patients with septic or cardiogenic shock display profoundly defective TNF alpha production in response to a broad range of infectious stimuli. Thus, down-regulation of cytokine production appears to occur in patients with systemic, but not localised, albeit severe, infections and also in patients with non-infectious circulatory failure. Whilst depletion of monocytes and reduced monocyte CD14 expression are likely to be critical components of the hyporesponsiveness observed in patients with septic shock, other as yet unidentified factors are at work in this group and in patients with cardiogenic shock.

[Endocarditis due to HACEK bacteria. A case report of endocarditis due to Kingella kingae]

Endocarditis is a common disease in hospital practice. Identification of the microorganism responsible for the valvular damage is essential to establish the prognosis and to determine the optimal antibiotic treatment. In some cases of endocarditis the diagnosis is laborious, especially when the responsible microorganism is difficult to detect using standard culture techniques. Here we report a case of native aortic valve endocarditis due to Kingella kingae, a Gram negative organism of the HACEK group. In addition we review 6 other cases of endocarditis caused by organism belonging to this group, treated in our hospital between 1983 and 1999. Epidemiological studies show that less than 5% of all cases of endocarditis are caused by organisms of the HACEK group. The diagnosis is often delayed because their slow growth on a standard culture medium. We describe clinical and microbiological characteristics of this group of endocarditis.

Use of botulinum toxin type A to avoid tracheal intubation or tracheostomy in severe paradoxical vocal cord movement

Paradoxical vocal cord movement (PVCM) is characterized by paradoxical adduction of the vocal cords during inspiration and/or expiration. Patients with severe forms of PVCM can present with acute dyspnea. In this article, we describe a patient with severe PVCM who had required tracheal intubation or tracheostomy at multiple occasions and who presented with acute hypercapnic respiratory failure. Using sedation and intralaryngeal injection of botulinum toxin type A, we could avoid more invasive intervention. Our observation shows that botulinum toxin type A should be considered in the acute care setting for severe PVCM.

Paxillin binding is not the sole determinant of focal adhesion localization or dominant-negative activity of focal adhesion kinase/focal adhesion kinase-related nonkinase

The carboxy-terminal 150 residues of the focal adhesion kinase (FAK) comprise the focal adhesion-targeting sequence, which is responsible for its subcellular localization. The mechanism of focal adhesion targeting has not been fully elucidated. We describe a mutational analysis of the focal adhesion-targeting sequence of FAK to further examine the mechanism of focal adhesion targeting and explore additional functions encoded by the carboxy-terminus of FAK. The results demonstrate that paxillin binding is dispensable for focal adhesion targeting of FAK. Cell adhesion-dependent tyrosine phosphorylation strictly correlated with the ability of mutants to target to focal adhesions. Focal adhesion targeting was also a requirement for maximal FAK-dependent tyrosine phosphorylation of paxillin and FAK-related nonkinase (FRNK)-dependent inhibition of endogenous FAK function. However, there were additional requirements for these latter functions because we identified mutants that target to focal adhesions, yet are defective for the induction of paxillin phosphorylation or the dominant-negative function of FRNK. Furthermore, the paxillin-binding activity of FRNK mutants did not correlate with their ability to inhibit FAK, suggesting that FRNK has other targets in addition to paxillin.

Tissue oxygenation and hemodynamic response to NO synthase inhibition in septic shock

The objective of the study was to evaluate the tissue oxygenation and hemodynamic effects of NOS inhibition in clinical severe septic shock. Eight patients with septic shock refractory to volume loading and high level of adrenergic support were prospectively enrolled in the study. Increasing doses of NOS inhibitors [N(G)-nitro-L-arginine-methyl ester (L-NAME) or N(G)-monomethyl-L-arginine (L-NMMA)] were administered as i.v. bolus until a peak effect = 10 mmHg on mean blood pressure was obtained or until side effects occurred. If deemed clinically appropriate, a continuous infusion of L-NAME was instituted and adrenergic support weaning attempted. The bolus administration of NOS inhibitors transiently increased mean blood pressure by 10 mm Hg in all patients. Seven out of eight patients received an L-NAME infusion, associated over 24 h with a progressive decline in cardiac index (P < 0.001) and an increase in systemic vascular resistance (P < 0.01). Partial or total adrenergic support weaning was rapidly possible in 6/8 patients. Oxygen transport decreased (P < 0.001), but oxygen consumption remained unchanged in those patients in whom it could be measured by indirect calorimetry (5/8). Blood lactate and the difference between tonometric gastric and arterial PCO2 remained unchanged. There were 4/8 ICU survivors. We conclude that nitric oxide synthase inhibition in severe septic shock was followed with a progressive correction of the vasoplegic hemodynamic disturbances with finally normalization of cardiac output and systemic vascular resistances without any demonstrable deterioration in tissue oxygenation.

Permissive hypercapnia impairs pulmonary gas exchange in the acute respiratory distress syndrome

Current recommendations for mechanical ventilation in the acute respiratory distress syndrome (ARDS) include the use of small tidal volumes (VT), even at the cost of respiratory acidosis. We evaluated the effects of this permissive hypercapnia on pulmonary gas exchange with the multiple inert gas elimination technique (MIGET) in eight patients with ARDS. After making baseline measurements, we induced permissive hypercapnia by reducing VT from 10 +/- 2 ml/kg to 6 +/- 1 ml/kg (mean +/- SEM) at constant positive end-expiratory pressure. After restoration of initial VT, we infused dobutamine to increase cardiac output (Q) by the same amount as with hypercapnia. Permissive hypercapnia increased Q by an average of 1.4 L. min(-)(1). m(2), decreased arterial oxygen tension from 109 +/- 10 mm Hg to 92 +/- 11 mm Hg (p < 0.05), markedly increased true shunt (Q S/Q T), from 32 +/- 6% to 48 +/- 5% (p < 0.0001), and had no effect on the dispersion of VA/Q.VA/Q. On reinstatement of baseline V T with maintenance of a high Q, Q S/Q T remained increased, to 38 +/- 6% (p < 0.05), and Pa(O(2 ))remained decreased, to 93 +/- 4 mm Hg (p < 0. 05). These results agreed with effects of changes in VT and Q predicted by the mathematical lung model of the MIGET. We conclude that permissive hypercapnia increases pulmonary shunt, and that deterioration in gas exchange is explained by the combined effects of increased Q and decreased alveolar ventilation.

[Carbon monoxide poisoning in children: never trivialize]

The risks linked to tissular hypoxemia after carbon monoxide (CO) poisoning are well known. Unawareness of CO exposure and of its complex pathophysiology may delay appropriate treatment and lead to long term neuropsychological sequelae. We report two cases of children treated in our institution and review the main issues regarding the optimal management. A high index of suspicion for carbon monoxide poisoning when dealing with an unclear neurological clinical presentation is mandatory. Classical therapy with normobaric 100% oxygen has to be instaured immediately. Hyperbaric oxygen therapy must be considered when anamnestic symptoms or clinical signs suggest neurological involvement even when carboxyhemoglobin values are low or already normalized.

The noncatalytic domain of protein-tyrosine phosphatase-PEST targets paxillin for dephosphorylation in vivo

The noncatalytic domain of protein-tyrosine phosphatase (PTP)-PEST contains a binding site for the focal adhesion-associated protein paxillin. This binding site has been narrowed to a 52-residue sequence that is composed of two nonoverlapping, weak paxillin binding sites. The PTP-PEST binding site on paxillin has been mapped to the two carboxyl-terminal LIM (lin11, isl-1, and mec-3) domains. Transient expression of PTP-PEST reduced tyrosine phosphorylation of p130(cas), as anticipated. A PTP-PEST mutant defective for binding p130(cas) does not cause a reduction in its tyrosine phosphorylation in vivo. Expression of PTP-PEST also caused a reduction of phosphotyrosine on paxillin. Expression of mutants of PTP-PEST with deletions in the paxillin-binding site did not associate with paxillin in vivo and failed to cause a reduction in the phosphotyrosine content of paxillin. These results demonstrate that paxillin can serve as a PTP-PEST substrate in vivo and support the model that a noncatalytic domain interaction recruits paxillin to PTP-PEST to facilitate its dephosphorylation.

The role of focal adhesion kinase binding in the regulation of tyrosine phosphorylation of paxillin

Focal adhesion kinase (FAK) and paxillin are focal adhesion-associated, phosphotyrosine-containing proteins that physically interact. A previous study has demonstrated that paxillin contains two binding sites for FAK. We have further characterized these two binding sites and have demonstrated that the binding affinity of the carboxyl-terminal domain of FAK is the same for each of the two binding sites. The presence of both binding sites increases the affinity for FAK by 5-10-fold. A conserved paxillin sequence called the LD motif has been implicated in FAK binding. We show that mutations in the LD motifs in both FAK-binding sites are required to dramatically impair FAK binding in vitro. A paxillin mutant containing point mutations in both FAK-binding sites was characterized. The mutant exhibited reduced levels of phosphotyrosine relative to wild type paxillin in subconfluent cells growing in culture, following cell adhesion to fibronectin and in src-transformed fibroblasts. These results suggest that paxillin must bind FAK for maximal phosphorylation in response to cell adhesion and that FAK may function to direct tyrosine phosphorylation of paxillin in the process of transformation by the src oncogene.

Clinical and radiologic features of pulmonary edema

Pulmonary edema may be classified as increased hydrostatic pressure edema, permeability edema with diffuse alveolar damage (DAD), permeability edema without DAD, or mixed edema. Pulmonary edema has variable manifestations. Postobstructive pulmonary edema typically manifests radiologically as septal lines, peribronchial cuffing, and, in more severe cases, central alveolar edema. Pulmonary edema with chronic pulmonary embolism manifests as sharply demarcated areas of increased ground-glass attenuation. Pulmonary edema with veno-occlusive disease manifests as large pulmonary arteries, diffuse interstitial edema with numerous Kerley lines, peribronchial cuffing, and a dilated right ventricle. Stage 1 near drowning pulmonary edema manifests as Kerley lines, peribronchial cuffing, and patchy, perihilar alveolar areas of airspace consolidation; stage 2 and 3 lesions are radiologically nonspecific. Pulmonary edema following administration of cytokines demonstrates bilateral, symmetric interstitial edema with thickened septal lines. High-altitude pulmonary edema usually manifests as central interstitial edema associated with peribronchial cuffing, ill-defined vessels, and patchy airspace consolidation. Neurogenic pulmonary edema manifests as bilateral, rather homogeneous airspace consolidations that predominate at the apices in about 50% of cases. Reperfusion pulmonary edema usually demonstrates heterogeneous airspace consolidations that predominate in the areas distal to the recanalized vessels. Postreduction pulmonary edema manifests as mild airspace consolidation involving the ipsilateral lung, whereas pulmonary edema due to air embolism initially demonstrates interstitial edema followed by bilateral, peripheral alveolar areas of increased opacity that predominate at the lung bases. Familiarity with the spectrum of radiologic findings in pulmonary edema from various causes will often help narrow the differential diagnosis.

Complex formation with focal adhesion kinase: A mechanism to regulate activity and subcellular localization of Src kinases

Tyrosine phosphorylation of focal adhesion kinase (FAK) creates a high-affinity binding site for the src homology 2 domain of the Src family of tyrosine kinases. Assembly of a complex between FAK and Src kinases may serve to regulate the subcellular localization and the enzymatic activity of members of the Src family of kinases. We show that simultaneous overexpression of FAK and pp60(c-src) or p59(fyn) results in the enhancement of the tyrosine phosphorylation of a limited number of cellular substrates, including paxillin. Under these conditions, tyrosine phosphorylation of paxillin is largely cell adhesion dependent. FAK mutants defective for Src binding or focal adhesion targeting fail to cooperate with pp60(c-src) or p59(fyn) to induce paxillin phosphorylation, whereas catalytically defective FAK mutants can direct paxillin phosphorylation. The negative regulatory site of pp60(c-src) is hypophosphorylated when in complex with FAK, and coexpression with FAK leads to a redistribution of pp60(c-src) from a diffuse cellular location to focal adhesions. A FAK mutant defective for Src binding does not effectively induce the translocation of pp60(c-src) to focal adhesions. These results suggest that association with FAK can alter the localization of Src kinases and that FAK functions to direct phosphorylation of cellular substrates by recruitment of Src kinases.

Focal adhesion targeting: the critical determinant of FAK regulation and substrate phosphorylation

The focal adhesion kinase (FAK) is discretely localized to focal adhesions via its C-terminal focal adhesion-targeting (FAT) sequence. FAK is regulated by integrin-dependent cell adhesion and can regulate tyrosine phosphorylation of downstream substrates, like paxillin. By the use of a mutational strategy, the regions of FAK that are required for cell adhesion-dependent regulation and for inducing tyrosine phosphorylation of paxillin were determined. The results show that the FAT sequence was the single region of FAK that was required for each function. Furthermore, the FAT sequence of FAK was replaced with a focal adhesion-targeting sequence from vinculin, and the resulting chimera exhibited cell adhesion-dependent tyrosine phosphorylation and could induce paxillin phosphorylation like wild-type FAK. These results suggest that subcellular localization is the major determinant of FAK function.

Successful implementation of guidelines for encouraging the use of beta blockers in patients after acute myocardial infarction

PURPOSE

To assess whether implementation of guidelines increases the prescription of drugs, particularly beta blockers, recommended for secondary prevention after acute myocardial infarction.

SUBJECTS AND METHODS

Prescription patterns among 355 patients discharged from a public teaching hospital after recovery from myocardial infarction were prospectively monitored in a before-after trial. The implementation strategies included educational interventions (large group meetings), placement of guidelines in patients' records, and bimonthly general reminders sent to physicians.

RESULTS

Beta blockers were prescribed in 93 (38%) of 243 survivors of acute myocardial infarction before guideline implementation (12-month control period), as compared with 71 (63%) of 112 patients (P <0.001) after their implementation (6-month period). During the entire study period, the prescription of beta blockers at a neighboring public teaching hospital, used as a comparison, was unchanged. After adjusting for potential confounders, implementation of the guidelines remained significantly associated with prescription of beta blockers at discharge [odds ratio (OR) = 10; 95% confidence interval (CI), 3.2 to 33; P <0.001]. Other independent predictors of prescription of beta blockers were previous coronary artery bypass grafting (OR = 8.7; 95% CI, 2.5 to 31; P = 0.001), hypertension (OR = 2.5; 95% CI, 1.4 to 4.5; P = 0.003), age per 10-year increase (OR = 0.82; 95% CI, 0.67 to 0.99; P = 0.04), secular trend in prescription patterns expressed in months (OR = 0.9; 95% CI, 0.8 to 1.0; P = 0.02), a left ventricular ejection fraction < or = 40% (OR = 0.2; 95% CI, 0.1 to 0.4; P <0.001), the presence of atrioventricular block (OR = 0.1; 95% CI, 0.02 to 0.7; P = 0.02), and concomitant prescription of digoxin (OR = 0.2; 95% CI, 0.05 to 0.8; P = 0.02) or calcium antagonists (OR = 0.06; 95% CI, 0.01 to 0.3; P = 0.001).

CONCLUSION

When appropriately developed and implemented by local experts, literature-based guidelines may be effective in modifying use of recommended drugs for secondary prevention of coronary artery disease, such as prescription of beta blockers.

NCAM stimulates the Ras-MAPK pathway and CREB phosphorylation in neuronal cells

The neural cell adhesion molecule NCAM plays an important role in axonal growth, learning, and memory. A signaling pathway has been elucidated in which clustering of the NCAM140 isoform in the neural plasma membrane stimulated the activating phosphorylation of mitogen-activated protein kinases (MAPKs) and the transcription factor cyclic AMP response-element binding protein (CREB). NCAM clustering transiently induced dual phosphorylation (activation) of the MAPKs ERK1 and ERK2 (extracellular signal-regulated kinases) by a pathway regulated by the focal adhesion kinase p125fak, p59fyn, Ras, and MAPK kinase. CREB phosphorylation at serine 133 induced by NCAM was dependent in part on an intact MAPK pathway. c-Jun N-terminal kinase, which is associated with apoptosis and cellular stress, was not activated by NCAM. Inhibition of the MAPK pathway in rat cerebellar neuron cultures selectively reduced NCAM-stimulated neurite outgrowth. These results define an NCAM signal transduction mechanism with the potential for modulating the expression of genes needed for axonal growth, survival, and synaptic plasticity.

[Therapeutic use of N-acetylcysteine in acute lung diseases]

Oxidants play a key role in disease processes, particularly in the detrimental mechanisms leading to tissue damage in certain forms of acute lung injury. A number of mediators contribute to the pathologic response in ARDS, SIRS or hyperoxia-induced pulmonary damage. One of the most important detrimental factors is the generation and activation of highly reactive oxygen species which are leading factors implicated in the process of tissue damage. N-acetylcysteine (NAC) is a free radical scavenger and might access the endothelial cell thus increasing intracellular glutathione (GSH) stores. Different studies have demonstrated that NAC might be a promising compound either for the prevention or the treatment of acute lung damages such as ARDS. However, the true beneficial effect so far reported in several clinical and experimental studies contrasts with some contradictory and intriguing aspects, probably because the significance of a direct in vivo antioxidative effect of this compound remains to be established in humans. Thus, the mode of action of NAC may not be the same in different pathologies and clinical situations. More research into the mechanisms of action of this unique xenobiotic substance may offer a clue for elucidating these controversies.

Confirmatory platelet-activating factor receptor antagonist trial in patients with severe gram-negative bacterial sepsis: a phase III, randomized, double-blind, placebo-controlled, multicenter trial. BN 52021 Sepsis Investigator Group

OBJECTIVE

To determine the efficacy and safety of using natural platelet-activating factor receptor antagonist (PAFra), BN 52021, to treat patients with severe Gram-negative bacterial sepsis.

DESIGN

A prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial.

SETTING

Fifty-nine academic medical center intensive care units in Europe.

PATIENTS

Six hundred nine patients with severe sepsis, suspected to be related to Gram-negative bacterial infection, who received PAFra or placebo.

INTERVENTIONS

Patients were randomized to receive either a dose of PAFra (120 mg iv) every 12 hrs over a 4-day period or placebo over a 4-day period.

MEASUREMENTS AND MAIN RESULTS

The patients were well matched at study entry for severity of illness and for risk factors known to influence the outcome of sepsis. Among all randomized patients, the 28-day, all-cause mortality rate was 49% (152/308) in the placebo group, and 47% (140/300) in the PAFra group (p=.50). When analyzed on the basis of the previously defined target population, the 28-day, all-cause mortality rate was 50% (115/232) in the placebo group and 44% (94/212) in the PAFra group, yielding a 12% reduction in mortality rate (p=.29). In patients with documented infection involving other organisms, there was no difference between treated and placebo groups. When the outcomes of organ dysfunctions were examined in the overall population and in the documented Gram-negative bacterial infection population, the number of patients who resolved hepatic dysfunction tended to be higher in the treated group than in the placebo group (p=.06). The number of adverse events reported were not different between the two groups.

CONCLUSIONS

A 4-day administration of the studied PAFra (BN 52021) failed to demonstrate a statistically significant reduction in the mortality rate of patients with severe sepsis suspected to be related to Gram-negative bacterial infection. If PAFra treatment has any therapeutic activity in severe Gram-negative bacterial sepsis, the incremental benefits are small and will be difficult to demonstrate in a patient population as defined by this clinical trial.

Direct association of protein-tyrosine phosphatase PTP-PEST with paxillin

Tyrosine phosphorylation of focal adhesion-associated proteins may be involved in the regulation of the cytoskeleton and in the control of signals for growth and survival. The focal adhesion kinase (FAK) functions in regulating tyrosine phosphorylation of several of these proteins, including paxillin, tensin, and p130(cas). Protein- tyrosine phosphatases, the counterparts of protein-tyrosine kinases, also presumably regulate phosphorylation of these proteins. We have tested the hypothesis that FAK intimately associates with a protein-tyrosine phosphatase. Protein-tyrosine phosphatase activity associated with the recombinant C-terminal domain of FAK in vitro and could be coimmunoprecipitated with both FAK and paxillin from lysates of chicken embryo cells. However, the interaction with FAK appeared to be indirect and mediated via paxillin. The protein-tyrosine phosphatase was subsequently identified as protein-tyrosine phosphatase-PEST, a nonreceptor protein-tyrosine phosphatase. The C-terminal noncatalytic domain of protein-tyrosine phosphatase-PEST directly bound to paxillin in vitro. The association of both a protein-tyrosine kinase and a protein-tyrosine phosphatase with paxillin suggests that paxillin may play a critical role in the regulation of the phosphotyrosine content of proteins in focal adhesions.

Epidemiology, diagnosis and treatment of systemic Candida infection in surgical patients under intensive care

The incidence of systemic Candida infections in patients requiring intensive care has increased substantially in recent years as a result of a combination of factors. More patients with severe underlying disease or immunosuppression from anti-neoplastic or anti-rejection chemotherapy and at risk from fungal infection are now admitted to the ICU. Improvements in supportive medical and surgical care have led to many patients who would previously have died as a result of trauma or disease surviving to receive intensive care. Moreover, some therapeutic interventions used in the ICU, most notably broad-spectrum antibiotics and intravascular catheters, are also associated with increased risks of candidiasis. Systemic Candida infections are associated with a high morbidity and mortality, but remain difficult to diagnose and ICU staff need to be acutely aware of this often insidious pathogen. A number of studies have identified risk factors for systemic Candida infection which may be used to identify those at highest risk. Such patients may be potential candidates for early, presumptive therapy. Here we review the epidemiology, pathogenesis, morbidity and mortality of systemic Candida infections in the ICU setting, and examine predisposing risk factors. Antifungal treatment, including the use of amphotericin B, flucytosine and fluconazole, and the roles of early presumptive therapy and prophylaxis, is also reviewed.

Extreme hypercapnia is not a long-term prognostic factor after near-fatal asthma: a 12-year follow-up study

QUESTION OF THE STUDY

Some patients experiencing near-fatal asthma present with extreme hypercapnia (PaCO2 > or = 100 mm Hg), whereas others do not. The influence of this factor on short- and long-term outcome and quality of life in these patients is still unknown.

PATIENTS AND METHODS

A series of 39 consecutive patients who had had an episode of near-fatal asthma between 1978 and 1992 were followed up. Long-term outcome and quality of life of the 12 patients who had experienced extreme hypercapnia were compared with those of the 27 patients who had not.

RESULTS

Four patients died, but only 1 from asthma. Three patients were lost to follow-up. The remaining 32 patients had a median observation period of 12.7 years. The hypercapnic patients did not significantly differ from the others in past asthma history, subsequent hospitalizations, medication needs, pulmonary function tests, quality of life and impairment/disability. In the event of subsequent near-fatal asthma attacks, they tended to present with hypercapnia levels similar to those observed during the first episode.

DISCUSSION

Extreme hypercapnia in near-fatal asthma tended to recur, but is not an aggravating long-term prognostic factor. Targeted surveillance of these high-risk patients should make it possible to reduce relapses and death rates from asthma.

SH2- and SH3-mediated interactions between focal adhesion kinase and Src

Intramolecular SH2 and SH3 interactions mediate enzymatic repression of the Src kinases. One mechanism of activation is disruption of these interactions by the formation of higher affinity SH2 and SH3 interactions with specific ligands. We show that a consensus Src SH3-binding site residing upstream of the Src SH2-binding site in FAK can function as a ligand for the Src SH3 domain. Surface plasmon resonance experiments indicate that a FAK peptide containing both the Src SH2- and SH3-binding sites exhibits increased affinity for Src. Furthermore, the presence of both sites in vitro more potently activates c-Src. A FAK mutant (FAKPro-2) with substitutions destroying the SH3-binding site shows reduced binding to Src in vivo. This mutation also reduces Src-dependent tyrosine phosphorylation on the mutant itself and downstream substrates, such as paxillin. These observations suggest that an SH3-mediated interaction between Src-like kinases and FAK may be important for complex formation and downstream signaling in vivo.

Nonselective versus selective inhibition of inducible nitric oxide synthase in experimental endotoxic shock

The effects of two nitric oxide synthase (NOS) inhibitors with different isoform selectivity were compared in a murine model of endotoxemia. Mice challenged with 70 mg/kg intraperitoneal (ip) lipopolysaccharide (LPS) were treated 6 h after LPS with either NG-gamma-L-arginine methyl ester (L-NAME, nonselective NOS inhibitor, 10-60 mg/kg), L-canavanine (selective inhibitor of inducible NOS, 50-300 mg/kg), or saline (0.2 mL) given ip. In a subset of mice, plasma concentrations of nitrate (NO breakdown product), lipase (pancreas injury), lactate dehydrogenase, and transaminases (liver injury) were measured 16 h after LPS. Although both inhibitors reduced plasma nitrate, they produced contrasting effects on survival and organ injury. L-NAME enhanced liver damage and tended to accelerate the time of death, while L-canavanine significantly reduced mortality and had no deleterious effects in terms of organ damage. These results indicate that nonselective NOS inhibitors are detrimental in endotoxic shock and support the potential usefulness of selective inducible NOS inhibitors in this setting.

Treatment with N-acetylcysteine during acute respiratory distress syndrome: a randomized, double-blind, placebo-controlled clinical study

PURPOSE

Intravenous N-acetylcysteine (NAC) has been reported to improve systemic oxygenation and reduce the need for ventilatory support in patients with an acute lung injury. In the more serious form, namely established adult respiratory distress syndrome (ARDS) (PaO2/FIO2 < or = 200 mm Hg), we tested the hypothesis that treatment with intravenous NAC may be beneficial.

MATERIALS AND METHODS

Respiratory dysfunction was graded daily according to the need for mechanical ventilation and FIO2 and to the evolution of the lung injury score (LIS) and the PaO2/FIO2 ratio in 42 patients with established ARDS receiving either NAC 190 mg/kg/day or placebo as a continuous intravenous infusion over the first 3 days of their clinical course.

RESULTS

NAC and placebo groups (22 and 20 patients, respectively) were comparable for demographic characteristics, ARDS categories, severity of illness (simplified acute physiology score [SAPS II]) LIS and PaO2/FIO2 ratio. Mortality rate was 32% for the NAC and 25% for the placebo group (difference not significant). At admission (day 1), 91% of patients in the NAC and 95% in the placebo group required ventilatory support; at days 2, 3, 5, and 7 after admission, the percentage of patients receiving ventilatory support was not significantly reduced for both groups in comparison with day 1. Moreover, there were no differences between the two groups at the same observation days. In both groups, the FIO2 was significantly lower and the PaO2/FIO2 ratio was significantly higher than the initial values during the evolution (FiO2 at day 3, P < .01 for NAC and P < .05 for placebo; PaO2/FIO2 at day 3: P < .01 for NAC and P < .02 for placebo), but this improvement was similar for both groups and, moreover, the between-group comparison was never significantly different at the various collection days. The LIS decreased significantly in NAC group between days 1 and 3 (2.23 +/- 0.62 v 1.76 +/- 0.17; P < .05), whereas no changes were observed in the placebo group; at day 5, there was a significant difference between the two groups (1.53 +/- 0.21 for the NAC v 2.15 +/- 0.19 for the placebo group; P < .05). In the prevalent sepsis category (10 patients in the NAC and 9 in the placebo group), the mortality rate, the need of ventilatory support, the intensive care unit stay, and the PaO2/FIO2 evolution did not differ significantly in both subgroups.

CONCLUSIONS

In this relatively small group of patients presenting with an established ARDS subsequent to a variety of underlying diseases, intravenous NAC treatment during 72 hours neither improved systemic oxygenation nor reduced the need for ventilatory support.

Differential signaling by the focal adhesion kinase and cell adhesion kinase beta

pp125(FAK) and CAKbeta/Pyk2/CadTK/RAFTK are related protein-tyrosine kinases. It is therefore of interest whether CAKbeta shares some of the properties of pp125(FAK). Using recombinant glutathione S-transferase fusion proteins, we show that the C-terminal domains of both proteins bind paxillin in vitro. The C-terminal domain of CAKbeta was engineered to be autonomously expressed in chicken embryo cells and, like pp125(FAK) and p41/43(FRNK) (the C-terminal noncatalytic domain of pp125(FAK)), was found to localize to cellular focal adhesions. In contrast, full-length CAKbeta was generally found diffusely distributed throughout the cell, although a fraction of the cells exhibited focal adhesion localization. Vanadate treatment of pp125(FAK)- and CAKbeta-overexpressing CE cells induced a dramatic increase in the phosphotyrosine content of a common set of proteins including tensin, paxillin, and p130(Cas), but some of these substrates, particularly p130(Cas), appeared to be differentially phosphorylated by pp125(FAK) and CAKbeta. Levels of tyrosine phosphorylation were higher in CAKbeta-overexpressing cells, and additional phosphotyrosine-containing species were specifically immunoprecipitated. In addition, vanadate treatment of CE cells overexpressing CAKbeta, but not pp125(FAK) overexpressors, induced a profound morphological change, which could be a consequence of the observed differences in substrate phosphorylation.