Interaction of pAsa5 and pAsa8 Plasmids in Aeromonas salmonicida subsp. salmonicida.

The plasmid known as pAsa5 is present in Aeromonas salmonicida subsp. salmonicida, a fish pathogen. The pAsa5 plasmid carries genes that are essential for the bacterium's virulence. Recombination events are known to occur in pAsa5, resulting in the loss of certain segments or the acquisition of additional genetic elements. For example, the transposon carried by the large pAsa8 plasmid was found to be inserted into the pAsa5 plasmid in the SHY16-3432 strain, enabling the addition of antibiotic resistance genes to this plasmid, which does not normally possess any. In this study, we present the isolation of additional strains carrying pAsa8. Further analyses of these strains revealed that a fusion between pAsa5 and the complete version of pAsa8 is possible. The pAsa8 transposon insertion in pAsa5 seen in the SHY16-3432 strain appears to be an aberrant event compared to the fusion of the two full-length plasmids. A 22-nucleotide sequence, present in both plasmids, serves as the site for the fusion of the two plasmids. Moreover, it is possible to introduce pAsa8 through conjugation into naive strains of A. salmonicida subsp. salmonicida and once the plasmid is within a new strain, the fusion with pAsa5 is detectable. This study reveals a previously unexplored aspect of pAsa5 plasmid biology, highlighting an additional risk for the spread of antibiotic resistance genes in A. salmonicida subsp. salmonicida.

People undertaking pulmonary rehabilitation are willing and able to provide accurate data via a remote pulse oximetry system: a multicentre observational study.

QUESTIONS: Can people referred to pulmonary rehabilitation easily learn to use a system for remote transmission of oximetry data? Do they consider remote transmission of oximetry data to be satisfactory? Are the transmitted data valid compared with locally stored data? DESIGN: Multicentre, prospective, observational study. PARTICIPANTS: One hundred and five adults with chronic respiratory disease who were referred to pulmonary rehabilitation. INTERVENTION: At an initial session, participants were taught to record and transmit their oximetry data to a remote server. At subsequent testing session(s), participants were requested to independently activate and use the oximetry monitoring system for a period of exercise on a cycle ergometer, until autonomy with the system was demonstrated. A subgroup of five participants undertook five 45-minute training sessions to generate a dataset to assess whether the transmitted data were valid compared with the locally stored data. OUTCOME MEASURES: Outcome measures included the number of sessions needed to become autonomous, participant satisfaction with the system, and measures of the validity of the transmitted data. RESULTS: Participants became autonomous quickly: 86% at the first testing session and 100% within three testing sessions. At least 98% of participants agreed that the system was easy to use and they would be willing to use it throughout pulmonary rehabilitation. The system transmitted usable data from 98% (95% CI 96 to 100) of sessions and introduced minimal artefact. Mean absolute differences were 0.365 beats/minute for heart rate and 0.133% for oxyhaemoglobin saturation. For heart rate, exact agreement was 72% (SD 9) and similar agreement (within 3 beats/minute) was 99% (SD 1). For oxyhaemoglobin saturation, exact agreement was 87% (SD 3) and similar agreement (within 3%) was 100% (SD 0). CONCLUSION: The telemonitoring system used in this study was sufficiently valid and acceptable for use in at-home pulmonary rehabilitation by people with chronic respiratory disease. STUDY REGISTRATION: ClinicalTrials.gov NCT03295474 and NCT03004716 (subgroup study).

Home-based Neuromuscular Electrical Stimulation as an Add-on to Pulmonary Rehabilitation Does Not Provide Further Benefits in Patients With Chronic Obstructive Pulmonary Disease: A Multicenter Randomized Trial.

OBJECTIVE: To assess the additional effect of a home-based neuromuscular electrical stimulation (NMES) program as an add-on to pulmonary rehabilitation (PR), on functional capacity in subjects with chronic obstructive pulmonary disease (COPD). DESIGN: Single-blind, multicenter randomized trial. SETTING: Three PR centers. PARTICIPANTS: Subjects with severe to very severe COPD (N=73; median forced expiratory volume in 1 second, 1L (25th-75th percentile, 0.8-1.4L) referred for PR. Twenty-two subjects discontinued the study, but only 1 dropout was related to the intervention (leg discomfort). INTERVENTION: Subjects were randomly assigned to either PR plus quadricipital home-based NMES (35Hz, 30min, 5 time per week) or PR without NMES for 8 weeks. MAIN OUTCOME MEASURE: The 6-minute walk test (6MWT) was used to assess functional capacity. RESULTS: Eighty-two percent of the scheduled NMES sessions were performed. In the whole sample, there were significant increases in the distance walked during the 6MWT (P<.01), peak oxygen consumption (P=.02), maximal workload (P<.01), modified Medical Research Council dyspnea scale (P<.01), and Saint George's Respiratory Questionnaire total score (P=.01). There was no significant difference in the magnitude of change for any outcome between groups. CONCLUSIONS: Home-based NMES as an add-on to PR did not result in further improvements in subjects with severe to very severe COPD; moreover, it may have been a burden for some patients.

Exercise testing in patients with diaphragm paresis.

PURPOSE: Diaphragm paresis (DP) is characterized by abnormalities of respiratory muscle function. However, the impact of DP on exercise capacity is not well known. This study was performed to assess exercise tolerance in patients with DP and to determine whether inspiratory muscle function was related to exercise capacity, ventilatory pattern and cardiovascular function during exercise. METHODS: This retrospective study included patients with DP who underwent both diaphragmatic force measurements, and cardiopulmonary exercise testing (CPET). RESULTS: Fourteen patients were included. Dyspnea was the main symptom limiting exertion (86%). Exercise capacity was slightly reduced (median VO2peak: 80% [74.5%-90.5%]), mostly due to ventilatory limitation. Diaphragm and overall inspiratory muscle function were correlated with exercise ventilation. Moreover, overall inspiratory muscle function was related with oxygen consumption (r=0.61) and maximal workload (r=0.68). CONCLUSIONS: DP decreases aerobic capacity due to ventilatory limitation. Diaphragm function is correlated with exercise ventilation whereas overall inspiratory muscle function is correlated with both exercise capacity and ventilation suggesting the importance of the accessory inspiratory muscles during exercise for patients with DP. Further larger prospective studies are needed to confirm these results.

Six-minute Stepper Test to Set Pulmonary Rehabilitation Intensity in Patients with COPD - A Retrospective Study.

Pulmonary rehabilitation (PR) improves outcomes in patients with chronic obstructive pulmonary disease (COPD). Optimal assessment includes cardiopulmonary exercise testing (CPET), but consultations are limited. Field tests could be used to individualize PR instead of CPET. The six-minute stepper test (6MST) is easy to set up and its sensitivity and reproducibility have previously been reported in patients with COPD. The aim of this study was to develop a prediction equation to set intensity in patients attending PR, based on the 6MST. The following relationships were analyzed: mean heart rate (HR) during the first (HR1-3) and last (HR4-6) 3 minutes of the 6MST and HR at the ventilatory threshold (HRvt) from CPET; step count at the end of the 6MST and workload at the Ventilatory threshold (VT) (Wvt); and forced expiratory volume in 1 second and step count during the 6MST. This retrospective study included patients with COPD referred for PR who underwent CPET, pulmonary function evaluations and the 6MST. Twenty-four patients were included. Prediction equations were HRvt = 0.7887 × HR1-3 + 20.83 and HRvt = 0.6180 × HR4-6 + 30.77. There was a strong correlation between HR1-3 and HR4-6 and HRvt (r = 0.69, p < 0.001 and r = 0.57, p < 0.01 respectively). A significant correlation was also found between step count and LogWvt (r = 0.63, p < 0.01). The prediction equation was LogWvt = 0.001722 × step count + 1.248. The 6MST could be used to individualize aerobic training in patients with COPD. Further prospective studies are needed to confirm these results.

Early-Phase Recovery of Cardiorespiratory Measurements after Maximal Cardiopulmonary Exercise Testing in Patients with Chronic Obstructive Pulmonary Disease.

Background. This study investigated respiratory gas exchanges and heart rate (HR) kinetics during early-phase recovery after a maximal cardiopulmonary exercise test (CPET) in patients with chronic obstructive pulmonary disease (COPD) grouped according to airflow limitation. Methods. Thirty control individuals (control group: CG) and 81 COPD patients (45 with "mild" or "moderate" airflow limitation, COPDI-II, versus 36 with "severe" or "very severe" COPD, COPDIII-IV) performed a maximal CPET. The first 3 min of recovery kinetics was investigated for oxygen uptake ([Formula: see text]O2), minute ventilation ([Formula: see text]), respiratory equivalence, and HR. The time for [Formula: see text]O2 to reach 25% (T1/4[Formula: see text]O2) of peak value was also determined and compared. Results. The [Formula: see text]O2, [Formula: see text], and HR recovery kinetics were significantly slower in both COPD groups than CG (p < 0.05). Moreover, COPDIII-IV group had significantly higher [Formula: see text]O2 and [Formula: see text] during recovery than COPDI-II group (p < 0.05). T1/4[Formula: see text]O2 significantly differed between groups (p < 0.01; 58 ± 18 s in CG, 79 ± 26 s in COPDI-II group, and 121 ± 34 s in COPDIII-IV) and was significantly correlated with forced expiratory volume in one second in COPD patients (p < 0.001, r = 0.53) and with peak power output (p < 0.001, r = 0.59). Conclusion. The COPD groups showed slower kinetics in the early recovery period than CG, and the kinetics varied with severity of airflow obstruction.

Physiologic assessment before video thoracoscopic resection for lung cancer in patients with abnormal pulmonary function.

BACKGROUND: Impaired respiratory function may prevent curative surgery for patients with non-small cell lung cancer (NSCLC). Video-assisted thoracoscopic surgery (VATS) reduces postoperative morbility-mortality and could change preoperative assessment practices and therapeutic decisions. We evaluated the relation between preoperative pulmonary function tests and the occurrence of postoperative complications after VATS pulmonary resection in patients with abnormal pulmonary function. METHODS: We included 106 consecutive patients with ≤80% predicted value of presurgical expiratory volume in one second (FEV1) and/or diffusing capacity of carbon monoxide (DLCO) and who underwent VATS pulmonary resection for NSCLC from a prospective surgical database. RESULTS: Patients (64±9.5 years) had lobectomy (n=91), segmentectomy (n=7), bilobectomy (n=4), or pneumonectomy (n=4). FEV1 and DLCO preoperative averages were 68%±21% and 60%±18%. Operative mortality was 1.89%. Only FEV1 was predictive of postoperative complications [odds ratio (OR), 0.96; 95% confidence interval (CI), 0.926-0.991, P=0.016], but there was no determinable threshold. Twenty-five patients underwent incremental exercise testing. Desaturations during exercise (OR, 0.462; 95% CI, 0.191-0.878, P=0.039) and heart rate (HR) response (OR, 0.953; 95% CI, 0.895-0.993, P=0.05) were associated with postoperative complications. CONCLUSIONS: FEV1 but not DLCO was a significant predictor of pulmonary complications after VATS pulmonary resection despite a low rate of severe morbidity. Incremental exercise testing seems more discriminating. Further investigation is required in a larger patient population to change current pre-operative threshold in a new era of minimally invasive surgery.

Postpneumonectomy Compression of the Mitral Annulus: Rare Vascular Complication in Sportive Patient.

Numerous postpneumonectomy complications exist. We present a rare clinical case of postpneumonectomy exertional dyspnea revealing compression of the mitral annulus by the descending aorta. The patient was 42-year-old former smoker with pulmonary emphysema. He has been operated on, in 2012 (i.e., right pneumonectomy). Before the surgery, the patient was a recreational runner. However, after some months, it was difficult for the patient to resume running. Cardiopulmonary exercise testing indicated moderate exercise intolerance with important oxygen desaturation. More interestingly, a decrease of low oxygen pulse was noticed from the first ventilatory threshold with no electrical modification on the electrocardiogram. This decrease was indicative of a decline in stroke volume. The thoracic scan revealed a right pneumonectomy pocket with a liquid abnormal content. Moreover, the mediastinum had shifted toward the pneumonectomy space and the left lung was distended and emphysematous. Echocardiography revealed a major change in the mediastinal anatomy. The mitral annulus was observed to be compressed by the rear wall of the descending aorta. The diagnosis of postpneumonectomy syndrome or platypnea-orthodeoxia syndrome was ruled out in this patient. Mitral annular compression by the descending aorta is rare complication, which must be researched in patients with postpneumonectomy exertional dyspnea.

Determinants of exercise capacity in cystic fibrosis patients with mild-to-moderate lung disease.

BACKGROUND: Adult patients with cystic fibrosis (CF) frequently have reduced exercise tolerance, which is multifactorial but mainly due to bronchial obstruction. The aim of this retrospective analysis was to determine the mechanisms responsible for exercise intolerance in patients with mild-to-moderate or severe disease. METHODS: Cardiopulmonary exercise testing with blood gas analysis at peak exercise was performed in 102 patients aged 28 ± 11 years: 48 patients had severe lung disease (FEV1 < 50%, group 1) and 54 had mild-to-moderate lung disease (FEV1 ≥ 50%, group 2). VO2 peak was measured and correlated with clinical, biological, and functional parameters. RESULTS: VO2 peak for all patients was 25 ± 9 mL/kg/min (65 ± 21% of the predicted value) and was < 84% of predicted in 82% of patients (100% of group 1, 65% of group 2). VO2 peak was correlated with body mass index, C-reactive protein, FEV1, FVC, RV, DLCO, VE/VCO2 peak, VD/VT, PaO2, PaCO2, P(A-a)O2, and breathing reserve. In multivariate analysis, FEV1 and overall hyperventilation during exercise were independent determinants of exercise capacity (R(2) = 0.67). FEV1 was the major significant predictor of VO2 peak impairment in group 1, accounting for 31% of VO2 peak alteration, whereas excessive overall hyperventilation (reduced or absent breathing reserve and VE/VCO2) accounted for 41% of VO2 alteration in group 2. CONCLUSION: Exercise limitation in adult patients with CF is largely dependent on FEV1 in patients with severe lung disease and on the magnitude of the ventilatory response to exercise in patients with mild-to-moderate lung disease.

Pavlovian-conditioned alcohol-seeking behavior in rats is invigorated by the interaction between discrete and contextual alcohol cues: implications for relapse.

INTRODUCTION: Drug craving can be independently stimulated by cues that are directly associated with drug intake (discrete drug cues), as well as by environmental contexts in which drug use occurs (contextual drug cues). We tested the hypothesis that the context in which a discrete alcohol-predictive cue is experienced can influence how robustly that cue stimulates alcohol-seeking behavior. METHODS: Male, Long-Evans rats received Pavlovian discrimination training (PDT) sessions in which one conditioned stimulus (CS+; 16 trials/session) was paired with ethanol (0.2 mL/CS+) and a second stimulus (CS-; 16 trials/session) was not. PDT occurred in a specific context, and entries into a fluid port where ethanol was delivered were measured during each CS. Next, rats were acclimated to an alternate (nonalcohol) context where cues and ethanol were withheld. Responses to the nonextinguished CS+ and CS- were then tested without ethanol in the alcohol-associated PDT context, the nonalcohol context or a third, novel context. RESULTS: Across PDT the CS+ elicited more port entries than the CS-, indicative of Pavlovian discrimination learning. At test, the CS+ elicited more port entries than the CS- in all three contexts: however, alcohol seeking driven by the CS+ was more robust in the alcohol-associated context. In a separate experiment, extinguishing the context-alcohol association did not influence subsequent CS+ responding but reduced alcohol seeking during non-CS+ intervals during a spontaneous recovery test. CONCLUSION: These results indicate that alcohol-seeking behavior driven by a discrete Pavlovian alcohol cue is strongly invigorated by an alcohol context, and suggest that contexts may function as excitatory Pavlovian conditioned stimuli that directly trigger alcohol-seeking behavior.

Multimodal nutritional rehabilitation improves clinical outcomes of malnourished patients with chronic respiratory failure: a randomised controlled trial.

BACKGROUND: In chronic respiratory failure (CRF), body composition strongly predicts survival. METHODS: A prospective randomised controlled trial was undertaken in malnourished patients with CRF to evaluate the effects of 3 months of home rehabilitation on body functioning and composition. 122 patients with CRF on long-term oxygen therapy and/or non-invasive ventilation (mean (SD) age 66 (10) years, 91 men) were included from eight respiratory units; 62 were assigned to home health education (controls) and 60 to multimodal nutritional rehabilitation combining health education, oral nutritional supplements, exercise and oral testosterone for 90 days. The primary endpoint was exercise tolerance assessed by the 6-min walking test (6MWT). Secondary endpoints were body composition, quality of life after 3 months and 15-month survival. RESULTS: Mean (SD) baseline arterial oxygen tension was 7.7 (1.2) kPa, forced expiratory volume in 1 s 31 (13)% predicted, body mass index (BMI) 21.5 (3.9) kg/m2 and fat-free mass index (FFMI) 15.5 (2.4) kg/m2. The intervention had no significant effect on 6MWT. Improvements (treatment effect) were seen in BMI (+0.56 kg/m2, 95% CI 0.18 to 0.95, p=0.004), FFMI (+0.60 kg/m2, 95% CI 0.15 to 1.05, p=0.01), haemoglobin (+9.1 g/l, 95% CI 2.5 to 15.7, p=0.008), peak workload (+7.2 W, 95% CI 3.7 to 10.6, p<0.001), quadriceps isometric force (+28.3 N, 95% CI 7.2 to 49.3, p=0.009), endurance time (+5.9 min, 95% CI 3.1 to 8.8, p<0.001) and, in women, Chronic Respiratory Questionnaire (+16.5 units, 95% CI 5.3 to 27.7, p=0.006). In a multivariate Cox analysis, only rehabilitation in a per-protocol analysis predicted survival (HR 0.27, 95% CI 0.07 to 0.95, p=0.042). CONCLUSIONS: Multimodal nutritional rehabilitation aimed at improving body composition increased exercise tolerance, quality of life in women and survival in compliant patients, supporting its incorporation in the treatment of malnourished patients with CRF. Clinical Trial number NCT00230984.

Effects of chronic aspirations on breathing pattern and ventilatory drive in vagatomized rats.

The aim of this study was to test the hypothesis that aspirations induced by unilateral vagotomy destabilise ventilatory pattern during swallowing. The study was carried out on 15 Wistar rats (2-3 months, 290-350 g) using whole-body plethysmography and video recordings, before and after unilateral vagotomy. The rats were given water ad libitum via a baby bottle fitted with a nipple. The experiment was continued until rest ventilation and swallowing periods were identified on the video recordings. Following the sectioning of the right vagus nerve, all the rats presented bronchial aspirations and unilateral vocal cord paralysis in the aperture position. After the vagotomy there were no changes at rest of the ventilatory variables compared to healthy controls. In healthy animals during swallowing, we observed a decrease in total ventilatory time (TTOT), a decrease in inspiratory time (TI) (p < 0.001), a decrease in expiratory time (TE) (p < 0.001), no change in tidal volume (VT) and an increase in mean inspiratory time (VT/TI) (p < 0.001) compared to the rest period. Animals with chronic aspiration presented during swallowing an increase in TTOT (p < 0.001), TI (p < 0.01), and TE (p < 0.001), no change in VT and a decrease of VT/TI (p < 0.001) and a modification of ventilatory pattern. In conclusion, our results confirmed that swallowing modifies ventilation in healthy animals and that chronic aspiration decreases ventilatory drive and modifies ventilatory pattern during swallowing.

Diaphragmatic effects of selective resection of the upper phrenic nerve root in dogs.

The aim of this study was to evaluate the effects on the diaphragm of upper phrenic nerve root resections in dogs. During laryngeal reinnervation, selective resections of the upper phrenic nerve root (C5) were performed unilaterally (right side, n=7; Group A) and bilaterally (n=6; Group B) and compared to non denervated animals (n=5). After 8 months, a diaphragmatic evaluation was performed: X-ray, EMG, transdiaphragmatic pressure (Pdi) after ipsi- and bilateral tetanic stimulation of the phrenic nerves and a bilateral histological study of five hemidiaphragmatic regions. EMG alterations were significantly more severe in Group B than in Group A, for the left (p<0.05) and right hemidiaphragms (p<0.01). No differences in the X-rays were noted between the three groups. The Pdi of the three groups after occlusion and phrenic nerve stimulations (unilateral and bilateral) were not statistically different. Histological data demonstrated that there were no differences in fibre irregularity, predominant fibre type or fibrosis between the three groups. Macroscopic and microscopic atrophy, which was mainly present on the anterior regions of the hemidiaphragms, was significantly higher in Group B than in Group A and undenervated dogs (p<0.05). In conclusion, resection of the upper phrenic nerve root of one phrenic nerve (right side) have limited effect on the diaphragm in dogs. However, resection of the upper phrenic nerve root on both sides resulted in a significant effect on the EMGs and histology of the entire diaphragm without any significant consequences on transdiaphragmatic pressure.

Spontaneous recovery of diaphragmatic strength in unilateral diaphragmatic paralysis.

The aim of the present study was to evaluate diaphragmatic strength in patients with unilateral diaphragmatic paralysis and to determine whether patients with recent diaphragm paralysis develop lower inspiratory pressure than patients with longstanding diaphragmatic paralysis. Twenty patients (16 men and 4 women, 62+/-12 years) and six control subjects were included (4 men and 2 women, 53+/-15 years) in the study. Esophageal pressure during sharp sniff (Pes,sniff), bilateral cervical phrenic nerve magnetic stimulation (Pes,cms) and unilateral phrenic nerve stimulation (Pes,ums) (in nine patients) were measured. Sixteen patients presented right diaphragmatic paralysis and four, left diaphragmatic paralysis. Pes,sniff was higher in control subjects than in patients with diaphragmatic paralysis (respectively 110+/-22 cmH2O and 82+/-24 cmH2O, P<0.05). There was no difference in Pes,cms between patients with diaphragmatic paralysis and control subjects (14+/-7 cmH2O vs. 16+/-4 cmH2O; ns). Pes,ums after stimulation of the affected phrenic nerve was less than 4 cmH2O, was 8+/-2 cmH2O after stimulation of the intact phrenic nerve and was correlated to Pes,cms (R=0.87, P<0.01). There was a positive correlation between Pes,cms, Pes,ums of the intact hemidiaphragm, Pes,sniff and the time from the onset of symptoms and the diaphragmatic explorations (respectively R=0.86, P<0.0001; R=0.72, P<0.05; R=0.48, P<0.05). In conclusion, diaphragmatic strength after unilateral diaphragmatic paralysis seems to improve with time.