Early development and gravitropic response of lateral roots in Arabidopsis thaliana.

Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.

Short term effect of recombinant tissue plasminogen activator in patients with hemodynamically stable acute pulmonary embolism: results of a meta-analysis involving 464 patients.

UNLABELLED: By considering studies where a mixing of patients with and without shock, with or without invasive procedure, treated with various thrombolytic agents through different ways of infusion, have been included, current meta-analyses on thrombolysis efficacy in Pulmonary embolism (PE) are of limited value. Modern management of PE includes the use of both non-invasive diagnostic methods and intravenous rt-PA as thrombolytic agent. METHODS: We performed a meta-analysis of all randomized trials comparing rt-PA with heparin in patients with hemodynamically stable pulmonary embolism. Only the events clearly identified as related with the venous thromboembolic disease or with the treatment were considered. RESULTS: Five studies involving 464 patients were included. The pooled estimate from all the trials revealed a non-statistically significant reduction in death related to PE or pulmonary recurrence for rt-PA compared with heparin (3.5% versus 4.6%; RR 0.97, 95% CI 0.38 to 2.51, P for heterogeneity among the studies=0.73). Compared with heparin, rt-PA was not associated with a significant increase in major bleeding (4.9% versus 4.6%; RR 0.94, 95% CI 0.39 to 2.27). Similar results were found when only studies including patients with echocardiographic evidence of right ventricular dysfunction were considered. CONCLUSION: Neither mortality due to pulmonary embolism nor objective pulmonary embolism recurrence are decreased by rt-PA compared with heparin in patients with hemodynamically stable pulmonary embolism. No benefit is suggested in studies including patients with right ventricular dysfunction alone.

Evaluation of colonisation of peripheral venous catheters inserted by prehospital emergency service teams (SMUR) in France.

There are no data in the literature on colonisation of peripheral venous catheters (PVCs) inserted by French prehospital emergency and resuscitation service teams (SMUR). In a descriptive and prospective study we evaluated colonisation of PVCs inserted and managed solely by a SMUR team. A total of 171 PVCs were analysed. Bacteriological results were positive for seven catheters (4.09%/threshold=10(2)cfu/mL). Our analyses of the characteristics of patients and interventions show a significantly higher number of elderly patients among those colonised (P=0.02) with less satisfactory venous access (P=0.006) and smaller catheter bores (P=0.009). No differences were seen regarding the other evaluation criteria: gender, aetiology, site of intervention, number and site of venepuncture procedures, blood pressure and duration of catheterisation. The absolute value of colonisation seen in our study appears consistent with those reported in the literature, but no comparisons are possible due to widely divergent catheterisation times between published work (days) and our own data (minutes). Our results suggest a reassessment of current recommendations of routine changeover of these catheters, with the attendant discomfort for patients and cost in terms of time and money. We recommend a randomised study comparing catheter colonisation levels associated with routine catheter replacement with targeted replacement based on risk factors.

Impact of restricting fluoroquinolone prescription on bacterial resistance in an intensive care unit.

The purpose of this study was to assess the effect of reducing prescription of fluoroquinolones in an intensive care unit (ICU) upon bacterial resistance, particularly as regards Pseudomonas aeruginosa. For six months between January 2001 and June 2001, administration of fluoroquinolones was kept to a minimum. A bacteriological screening of patients was performed to assess the incidence of fluoroquinolone-resistant bacteria. There was a 75.8% restriction in prescriptions of fluoroquinolones. There was no significant change in bacterial ecology between the periods preceding (12 months) and following (12 months) restriction. There was a significant recovery of sensitivity of P. aeruginosa to ciprofloxacin (P

The oxygenation variations related to prone positioning during mechanical ventilation: a clinical comparison between ARDS and non-ARDS hypoxemic patients.

OBJECTIVES: To compare, in clinical practice, the oxygenation variations related to prone positioning (PP) during mechanical ventilation in ARDS and non-ARDS hypoxemic patients. DESIGN AND SETTING: Prospective observational study of data on consecutive patients treated with the same protocol in the intensive care unit (ICU) of a university hospital. PATIENTS: From May 1996 to December 1998, 226 PP periods without adjunction of nitric oxide (NO) inhalation and/or almitrine bismesylate infusion, performed in 59 mechanically ventilated hypoxemic patients (arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) ratio <300 mmHg) with no evidence of left ventricular failure, were included in this study. MEASUREMENTS: Arterial blood gas was measured before the PP, at 1 h from the beginning of the PP, at the end of the PP and 1 h after returning to the supine position. RESULTS: We analyzed 136 PP periods in 34 non-ARDS patients (60.2%) and 90 in 25 ARDS patients. The PP was repeated and the duration of the PP periods was: 10.6+/-0.22 h. The PP during the mechanical ventilation appeared to be safe and well tolerated. A PaO2/FIO2 ratio improvement at the end of the PP period, occurred for 196 periods (86.7%) with a mean PaO2/FIO2 ratio increase of +46.4+/-0.03% at the end of the PP periods compared to the baseline supine value. The PaO2/FIO2 ratio variations at 1 h after the start of the PP, at the end of the PP period and at 1 h after the return to supine were not different in ARDS or non-ARDS hypoxemic patients. The PaO2/FIO2 ratio improvement appeared to be more intense and more rapid in ARDS patients. CONCLUSIONS: In about 90% of periods, PP improved the PaO2/FIO2 ratio in patients with ARDS as well as in hypoxemic patients with non-ARDS. Studies are necessary to determine the impact of PP on survival and the mechanical ventilation duration in ARDS or non-ARDS hypoxemic patients.

[Rapid diagnosis of the type of meningitis (bacterial or viral) by the assay of serum procalcitonin]. / Diagnostic rapide du type de méningite (bactérienne ou virale) par le dosage de la procalcitonine sérique.

OBJECTIVE: It has been shown that serum procalcitonin (PCT) can be used to differentiate bacterial from viral meningitis in children in all cases. The aim of this study was to demonstrate the interest of PCT in the management of suspected meningitis in adults. PATIENTS AND METHODS: We conducted a prospective study including 179 consecutive patients admitted to the emergency department for suspected meningitis. All samples were taken at patient admission. The discriminant potential between bacterial and viral meningitis was studied for cerebrospinal fluid parameters (cytology, protein, glucose, lactate) and serum parameters (C reactive protein, PCT). RESULTS: Thirty-two patients had bacterial meningitis, 90 had viral meningitis and meningitis was ruled out in 57. Among all studied parameters, the most discriminant for distinguishing between bacterial and viral meningitis in 100% of the cases proved to be serum procalcitonin with a threshold value of 0.93 ng/ml. CONCLUSION: Serum procalcitonin is an interesting parameter in the emergency department for management of meningitis suspicion in adults.