Light ion source for proton∕deuteron production at CEA Saclay for the Spiral2 project.

The production of rare radioactive ion beam (RIB) far from the valley of stability is one of the final purposes of the Spiral2 facility in Caen. The RIB will be produced by impinging a deuteron beam onto a carbon sample to produce a high neutron flux, which will interact with a uranium target. The primary deuteron beam is produced by an ion source based on ECR plasma generation. The deuteron source and the low energy beam transport (LEBT) has been assembled and tested at CEA Saclay. Diagnostics from other laboratories were implemented on the LEBT in order to characterize the deuteron beam produced and compare it to the initial simulations. The ion source has been based on a SILHI-type source, which has demonstrated good performances in pulsed and continuous mode, and also a very good reliability on long term operation. The 5 mA of deuteron beam required at the RFQ entrance is extracted from the plasma source at the energy of 40 kV. After a brief description of the experimental set-up, this article reports on the first beam characterization experiments.

Classification of sleep-disordered breathing.

Increasing recognition of sleep-disordered breathing (SDB) and its morbidity have prompted reevaluation of techniques to identify respiratory events during sleep. The present study was designed to evaluate the utility of various metrics of SDB and to identify the optimal respiratory metric that objectively correlates to symptoms of excessive daytime somnolence (EDS). Metrics were derived from combinations of conventional apnea/hypopnea, flow limitation events (transient elevated upper airway resistance identified by characteristic flattening on the flow/time tracing, using a noninvasive nasal cannula technique), desaturation, and arousal. A total of 137 subjects underwent clinical evaluation and nocturnal polysomnogram. In 34 randomly selected subjects, the best metrics for discriminating between 13 subjects with no EDS/snoring and 21 patients with EDS and snoring were identified by receiver operator curve analysis. Of the metrics and cut points tested, a total respiratory disturbance index (RDI(Total), sum of apneas, hypopnea, and flow limitation events) of 18 events/h was found to have the best discriminant ability (100% sensitivity and 96% specificity). Prospective testing of this metric was then performed with the remaining 103 subjects (14 nonsnoring non-EDS, 21 snoring non-EDS, 68 snoring with EDS). Using this cutoff of 18 events/h, we obtained 71% sensitivity and 60% specificity for identifying subjects with EDS. We conclude that, in subjects with upper airway dysfunction, an index that incorporates all respiratory events provides the best quantitative physiological correlate to EDS.

[Auto-controlled continuous positive pressure in the titration and treatment of obstruction sleep disorders]. / Pression positive continue auto-pilotée dans la titration et le traitement des troubles respiratoires obstructifs du sommeil.

Self-adjusted Continuous Positive Airway Pressure or autoCPAP machines have been engineered to automatically adjust the pressure to maintain the upper airway patency. They can be used for titration or long-term home therapy. They have been developed to improve efficiency and compliance of CPAP treatment and the cost-effectiveness of titration and also to decrease the long waiting lists for manual titration. For the treatment, it is believed, but not demonstrated, that compliance may be increased by lowering the optimal pressure. Most machines are piloted by an algorithm based on detection of various combination of respiratory events such as apnoeas, hypopnoeas, snoring, inspiratory flow limitation or impedance. Several short-term studies have shown that autoCPAP reduces the indices of respiratory events and microarousals. In general, optimal CPAP determined automatically are identical or lower than evaluated manually by experienced technicians. However, the long-term benefits of auto-CPAP on compliance have not been determined and require further controlled clinical studies taking account not only compliance, but also sleep quality, quality of life, alertness and cognition for each autoCPAP. The cost-effectiveness of auto-titration versus conventional titration remains also to be established.

[Auto-CPAP in the titration and treatment of obstructive respiratory sleep disorders]. / Pression positive continue auto-pilotée dans la titration et le traitement des troubles respiratoires obstructifs du sommeil.

Self-adjusted Continuous Positive Airway Pressure or autoCPAP machines have been engineered to automatically adjust the pressure to maintain the upper airway patency. They can be used for titration or long-term home therapy. They have been developed to improve efficiency and compliance of CPAP treatment and the cost-effectiveness of titration and also to decrease the long waiting lists for manual titration. For the treatment, it is believed, but not demonstrated, that compliance may be increased by lowering the optimal pressure. Most machines are piloted by an algorithm based on detection of various combination of respiratory events such as apnoeas, hypopnoeas, snoring, inspiratory flow limitation or impedance. Several short-term studies have shown that autoCPAP reduces the indices of respiratory events and microarousals. In general, optimal CPAP determined automatically are identical or lower than evaluated manually by experienced technicians. However, the long-term benefits of auto-CPAP on compliance have not been determined and require further controlled clinical studies taking account not only compliance, but also sleep quality, quality of life, alertness and cognition for each autoCPAP. The cost-effectiveness of auto-titration versus conventional titration remains also to be established.

Relative occurrence of flow limitation and snoring during continuous positive airway pressure titration.

OBJECTIVES: To examine the relative temporal appearance of flow limitation and snoring during continuous positive airway pressure (CPAP) titration, compare their sensitivity as indicators of airway obstruction, and assess their relative utility as feedback variables for automatic titration of CPAP. DESIGN: Retrospective review of data. SETTING: University teaching hospital. PATIENTS: Fifty-three patients diagnosed as having obstructive sleep apnea or upper airway resistance syndrome undergoing CPAP titration. MEASUREMENTS AND RESULTS: We used a prototype automatic CPAP device that adjusts pressure in response to apnea, snoring, and/or flow limitation. The present study takes advantage of the frequent automatic decreases in pressure from a therapeutic level, as well as any technician-initiated decreases in pressure. We tabulated, for each pressure decrease of >0.4 cm H2O, the occurrences of snoring alone, flow limitation alone, or simultaneous appearance of both. Of 2,177 automatic pressure decreases, 64% resulted in flow limitation alone, 8% in snoring alone, and 22% in the simultaneous occurrence of both. Overall, 86% of decreases resulted in flow limitation alone or were simultaneous with snoring, whereas 30% of decreases resulted in snoring alone or were simultaneous with flow limitation. In 10 of 35 patients, snoring alone occurred in > 10% of the pressure decreases. In all but 5 of 133 manual pressure decreases, flow limitation developed at or above the pressure at which snoring developed. CONCLUSIONS: While detection of snoring occasionally provided additional information, overall flow limitation was the earliest indicator of obstruction during decreases in CPAP.

Detection of flow limitation with a nasal cannula/pressure transducer system.

We previously showed that upper airway resistance can be inferred from the inspiratory flow contour during continuous positive airway pressure (CPAP) titration in obstructive sleep apnea syndrome (OSAS). The present study examines whether similar information can be obtained from inspiratory flow measured by a nasal cannula/pressure transducer. Ten symptomatic patients (snoring, upper airway resistance syndrome [UARS], or OSAS) and four asymptomatic subjects underwent nocturnal polysomnography (NPSG) with monitoring of flow (nasal cannula) and respiratory driving pressure (esophageal or supraglottic catheter). For each breath the inspiratory flow signal was classified as normal, flattened, or intermediate by custom software. "Resistance" was calculated from peak inspiratory flow and pressure, and normalized to the resistance during quiet wakefulness. Resistance in all stages of sleep was increased for breaths with flattened (387 +/- 188%) or intermediate (292 +/- 163%) flow contour. In combination with apnea-hypopnea index (AHI), identification of "respiratory events," consisting of consecutive breaths with a flattened contour, allowed differentiation of symptomatic from asymptomatic subjects. Our data show that development of a plateau on the inspiratory flow signal from a nasal cannula identifies increased upper airway resistance and the presence of flow limitation. In patients with symptoms of excessive daytime somnolence and low AHI this may help diagnose the UARS and separate it from nonrespiratory causes of sleep fragmentation.

Effect of oxidant air pollutants on the respiratory system: insights from experimental animal research.

In the present paper, we have reviewed experimental animal studies on the effects of the two most important oxidant airborne pollutants, nitrogen dioxide and ozone, on the respiratory system. The toxic effects depend on concentration and length of exposure, and are generally similar for both oxidants, with ozone operative at lower concentrations. High doses of both oxidants cause death due to lung oedema. Exposure to sublethal levels causes functional alterations such as airflow limitation and airway hyperresponsiveness to bronchoconstrictor stimuli. These effects, which are generally reversible, are associated with epithelial injury, oedema and airway and parenchymal infiltration by inflammatory cells. Loss of cilia of airway epithelium and necrosis of type I alveolar epithelial cells are the most prominent consequences at the epithelial level. Inflammation is characterized by early neutrophilic infiltration, followed by an increased number of mononuclear cells, predominantly alveolar macrophages. After long-term exposure, whilst nitrogen dioxide causes predominantly emphysema, ozone produces mainly pulmonary fibrosis. Biochemical effects include lipid peroxidation, increased antioxidant metabolism, and alteration of enzyme activity. Nitrogen dioxide and ozone may also alter the immunological response and reduce the defence against infections, increasing the susceptibility of exposed animals to infections.

[Role of adhesion molecules in bronchial inflammation and bronchial hyperreactivity]. / Rôle des molécules d'adhésion dans l'inflammation bronchique et l'hyperréactivité bronchique.

Adhesion molecules are glycoproteins situated in the cell membrane. These molecules permit cells to integrate specifically with the specific cellular receptors or ligands and with the extracellular matrix during intra-tissular migration. Structurally, 4 large families can be distinguished: the immunoglobulin family, the integrins, the selectines, and finally the cadherines. The results of preliminary studies in man seem to confirm those obtained in vivo and in vitro in animals. The in vitro studies have shown that overall the inflammatory cells, such as the eosinophils as well as the endothelial and epithelial cells have many adhesion molecules, the regulation of which is dependent on many cytokinetic mediators, such as interleukin 1 beta (IA-1 beta), tumour necrosis factor (TNF alpha) and interleukin 4 (IL4). In man, it has been observed that there is a significant increase in TNF alpha in the bronchial mucosae of asthmatics. Together, the experimental studies have shown the crucial role of adhesion molecules in specific recruitment and their regulation by cytokines in the physiopathology of bronchial inflammation and hyper-reactivity that are characteristic of asthmatic disease.

Measurement of respiratory impedance by forced oscillation: comparison of the standard and head generator methods.

Physiological and clinical studies have shown that the standard method of measuring respiratory impedance by forced oscillation leads to less efficient control of the upper airway shunt effect than the head generator method. To test the effects of these two techniques in epidemiological studies, we compared, in a sample of 73 French agricultural workers, the values obtained with each method for five forced oscillation parameters: resistance, frequency dependence of resistance, inertance, compliance and resonant frequency. For these comparisons, subjects were classified according to four respiratory status factors: smoking status, cough, expectoration and airway obstruction assessed from the maximum expiratory flow volume curve. Logistic regression models using the set of four forced oscillation parameters (excluding resonant frequency, which is derived from compliance and inertance) were then used to analyse the ability of each method to classify the subjects in each group. Significant differences between the two methods were observed for the mean values obtained for all five parameters. However, when each parameter was considered separately, the correlations between the values for each method were significant. Each method possessed the necessary ability to separate subjects into our group classification, but the significant relationships were not always found for the same parameters. Finally, logistic regression models showed that the two methods led to almost the same classification of the subjects. According to our results, the standard method of applying forced oscillation at the mouth seems an acceptable device for measuring respiratory impedance for epidemiological purposes.

Sputum eosinophilia after asthmatic responses induced by isocyanates in sensitized subjects.

To assess the nature and the time-course of the cellular component of airway inflammation induced by isocyanates, we examined nine subjects with occupational asthma induced by toluene- or methylene diphenyl-diisocyanate (TDI, MDI) and four control subjects never exposed to isocyanates. Sputum was induced by inhalation of ultrasonically nebulized hypertonic saline (3-4% NaCl) before and 8, 24, 48 h after inhalation challenge with TDI or MDI. Expectorated samples were incubated with dithiothreitol, washed and cytocentrifuged. Differential cell counts were obtained on slides stained with May-Grünwald-Giemsa. Metachromatic cells (mast cells and basophils) were counted on slides stained with toluidine blue at pH 0.1. One occupational asthmatic exhibited a dual reaction to TDI, two exhibited a single early asthmatic reaction to MDI, six exhibited a late asthmatic reaction to TDI (n = 5) or MDI (n = 1), whereas no reactions were observed in control subjects after TDI challenge. In sensitized subjects eosinophils increased from a median value (interquartile range) of 5 (15)% before challenge to 29 (29)% (P = 0.014) and to 30 (31)% (P = 0.031) 8 and 24 h after TDI/MDI challenges, respectively. Sputum eosinophilia was observed both in early and late reactors and declined to near to baseline values 48 hr after challenge. Percentages of eosinophils in control subjects did not exceed 7% during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycotic aneurysm of the upper abdominal aorta ruptured into the stomach.

We report a case of primary aortogastric fistula with erosion of a mycotic aneurysm of the upper abdominal aorta into the stomach. The patient was successfully operated on with an in situ aortoaortic tube graft, incorporating the splanchnic vessels, and direct suture of the gastric erosion.