Striking difference between alkane and olefin metathesis using the well-defined precursor [Si–O–WMe5]: indirect evidence in favour of a bifunctional catalyst W alkylidene–hydride

Metathesis of linear alkanes versus olefins using supported multifunctional catalyst gives a very striking different distribution of metathesis products.

Non specific pattern of lung function in a respiratory physiology unit: causes and prevalence: results of an observational cross-sectional and longitudinal study

Background

ATS/ERS Task Force has highlighted that special attention must be paid when FEV₁ and FVC are concomitantly decreased (<5^th percentile) and the FEV₁/FVC ratio is normal (>5^th percentile) because a possible cause of this non specific pattern (NSP) is collapse of small airways with normal TLC measured by body plethysmography (>5^th percentile). Our objectives were to determine the main lung diseases associated with this pattern recorded prospectively in a lung function testing (LFT) unit, the prevalence of this pattern in our LFT and among the diseases identified, and its development.

Methods

Observational study of routinely collected data selected from our Clinical Database Warehouse.

Results

The prevalence of NSP was 841/12 775 tests (6.6%, 95% CI: 6.2 to 7.0%). NSP was mainly associated with seven lung diseases: asthma (prevalence of NSP among asthmatics: 12.6%), COPD/emphysema (prevalence 8.6%), bronchiectasis (12.8%), sarcoidosis (10.7%), interstitial pneumonia (4.0%), pulmonary hypertension (8.9%) and bilateral lung transplantation for cystic fibrosis (36.0%). LFT measurements were described in 185 patients with NSP and indisputable nonoverlapping causes. A moderate defect (FEV₁: 66 ± 9% predicted) with mild lung hyperinflation (FRC: 111 ± 27%, RV: 131 ± 33% predicted: suggesting distal airway obstruction) was evidenced whatever the underlying cause. A long term stability of NSP was evidenced in 130/185 patients (70% 95% CI: 64 to 77%).

Conclusions

NSP is observed in asthma, COPD/emphysema, bronchiectasis, sarcoidosis, pulmonary hypertension, interstitial pneumonia and after bilateral lung transplantation and remains stable in the majority of patients.

Prevalence of overestimation or underestimation of the functional capacity using MRC score as compared to 6-minute walk test in patients with cardio-respiratory disorders

OBJECTIVES

The first objective of our study was to assess whether patients diagnosed with cardio-respiratory disorders report overestimation or underestimation on recall (Medical Research Council (MRC) dyspnea scale) of their true functional capacity (walked distance during a 6-minute walk test (6MWT)). The second objective was to assess whether the measurement of breathlessness at the end of a 6MWT (Borg score) may help to identify dyspneic patients on recall.

METHODS

The 6MWTs of 746 patients aged from 40 to 80 years who were diagnosed with either chronic obstructive pulmonary disease (COPD, n = 355), diffuse parenchymal lung disease (n = 140), pulmonary vascular diseases (n = 188) or congestive heart failure (n = 63) were selected from a prospective Clinical Database Warehouse.

RESULTS

The percentage of patients who overestimated (MRC ≤ 2 with distance < lower limit of normal (LLN), 61/746, 8%; 95% confidence interval (CI): 6 to 10%) or underestimated (MRC > 2 with distance ≥LLN, 121/746, 16%; 95%CI: 14 to 19%) on recall their capacity was elevated. The overestimation seemed related to self-limitation, while the underestimation seemed related to patients who "work through" their breathing discomfort. These two latter groups of patients were mainly diagnosed with COPD. A Borg dyspnea score >3 (upper limit of normal) at the end of the 6MWT had 84% specificity for the prediction of a MRC score >1.

CONCLUSION

Almost one fourth of patients suffering from cardio-pulmonary disorders overestimate or underestimate on recall their true functional capacity. An elevated Borg dyspnea score at the end of the 6MWT has a good specificity to predict dyspnea on recall.

Direct observation of supported W bis-methylidene from supported W-methyl/methylidyne species

Direct observation of supported W bis-methylidene from supported W methyl/methylidyne species.

Cross-sectional assessment of the roles of comorbidities in resting and activity-related dyspnea in severely obese women

OBJECTIVES

Obesity has been associated with a lesser degree of asthma control that may be biased by other comorbidities. The objectives of this cross-sectional study were to describe resting and activity-related dyspnea complaints according to the presence of obesity-related comorbidities (asymptomatic airway hyperresponsiveness (AHR), asthma, gastroesophageal reflux disease (GERD) and sleep-disordered breathing (SDB)). We hypothesized that obese women can exhibit both resting and activity-related dyspnea, independently of the presence of asthma.

METHODS

Severely obese (body mass index (BMI) > 35 kg m(-2)) women prospectively underwent description of resting and activity-related dyspnea (verbal descriptors and Medical Research Council (MRC) scale), pulmonary function testing (spirometry, absolute lung volumes, and methacholine challenge test), oesogastro-duodenal fibroscopy, and overnight polygraphy. Thirty healthy lean women without airway hyperresponsiveness were enrolled.

RESULTS

Resting dyspnea complaints were significantly more prevalent in obesity (prevalence 41%) than in healthy lean women (prevalence 3%). Chest tightness and the need for deep inspirations were independently associated with both asthma and GERD while wheezing and cough were related to asthma only in obese women. Activity-related dyspnea was very prevalent (MRC score > 1, 75%), associated with obesity, with the exception of wheezing on exertion due to asthma. Asymptomatic AHR and SDB did not affect dyspneic complaints.

CONCLUSIONS

In severely obese women referred for bariatric surgery, resting dyspnea complaints are observed in association with asthma or GERD, while activity-related dyspnea was mainly related to obesity only. Consequently, asthma does not explain all respiratory complaints of obese women.

Relationships between respiratory and airway resistances and activity-related dyspnea in patients with chronic obstructive pulmonary disease

Background

The aims of the study were: (1) to compare numerical parameters of specific airway resistance (total, sRaw_tot, effective, sRaw_eff and at 0.5 L · s⁻¹, sRaw_0.5) and indices obtained from the forced oscillation technique (FOT: resistance extrapolated at 0 Hz [Rrs_{0 Hz}], mean resistance [Rrs_mean], and resistance/frequency slope [Rrs_slope]) and (2) to assess their relationships with dyspnea in chronic obstructive pulmonary disease (COPD).

Methods

A specific statistical approach, principal component analysis that also allows graphic representation of all correlations between functional parameters was used. A total of 108 patients (mean ± SD age: 65 ± 9 years, 31 women; GOLD stages: I, 14; II, 47; III, 39 and IV, 8) underwent spirometry, body plethysmography, FOT, and Medical Research Council (MRC) scale assessments.

Results

Principal component analysis determined that the functional parameters were described by three independent dimensions (airway caliber, lung volumes and their combination, specific resistance) and that resistance parameters of the two techniques were not equivalent, obviously. Correlative analyses further showed that Raw_tot and Raw_eff (and their specific resistances) can be considered as equivalent and correlated with indices that are considered to explore peripheral airways (residual volume (RV), RV/ total lung capacity (TLC), Rrs_slope), while Rrs_mean and Raw_0.5 explored more central airways. Only specific resistances taking into account the specific resistance loop area (sRaw_tot and sRaw_eff) and Rrs_slope were statistically linked to dyspnea.

Conclusion

Parameters obtained from both body plethysmography and FOT can explore peripheral airways, and some of these parameters (sRaw_tot, sRaw_eff, and Rrs_slope) are linked to activity-related dyspnea in moderate to severe COPD patients.

Cardiac valve papillary fibro-elastoma: a report on three different clinical cases

Cardiac papillary fibro-elastoma is a rare benign endocardial tumour predominantly affecting the aortic and mitral valves. We report three cases with different clinical presentations, and discuss the diagnostic and therapeutic strategies.

Nitric oxide evaluation in upper and lower respiratory tracts in nasal polyposis

BACKGROUND

A decrease in nasal nitric oxide (NO) and an increase in exhaled NO have been demonstrated in patients with nasal polyposis (NP).

OBJECTIVES

The aims were to evaluate the flux of NO from the three compartments of the respiratory tract, namely, upper nasal, lower conducting and distal airways, and to search for relationships between NO parameters and indexes of upper and lower disease activity (bronchial reactivity and obstruction). The effect of medical treatment of polyposis was also evaluated.

METHODS

Seventy patients with polyposis were recruited. At baseline, pulmonary function tests (spirometry, plethysmography, bronchomotor response to deep inspiration using forced oscillation measurement of resistance of respiratory system, methacholine challenge, multiple flow rates of exhaled NO and nasal NO measurements) were performed together with an assessment of polyposis [clinical, endoscopic and computed tomography (CT) scores].

RESULTS

Statistical relationships were demonstrated between nasal NO flux and severity scores (clinical: rho=-0.31, P=0.015; endoscopic: rho=-0.57, P<0.0001; CT: rho=-0.46, P=0.0005), and between alveolar NO concentration and distal airflow limitation (FEF(25-75), rho=-0.32, P=0.011). Thirty-six patients were assessed after 11 [7-13] (median [interquartile]) months of medical treatment, demonstrating an improvement in clinical and endoscopic scores, an increase in nasal NO flux, a decrease in NO flux from conducting airways, an improvement in the mild airflow limitation (forced expiratory volume in 1 s, FEF(25-75), even in non-asthmatic patients) and a decrease in the bronchoconstrictor effect of deep inspiration.

CONCLUSIONS

The medical treatment of NP improves both airway reactivity and obstruction, whatever the presence of asthma, suggesting a functional link between upper and lower airway functions.

[Potential importance of antileukotrienes in the treatment of asthma and other inflammatory diseases: apropos of a new pharmacological class]

OBJECTIVES

Among the mediators involved in the asthma bronchoconstriction and inflammation mechanisms, there is now substantial evidence that the sulfidopeptide leukotrienes (LTs) are important. Antagonists of their receptors and inhibitors of their synthesis have been developed.

IMPORTANT POINTS

Antagonists of LTs, as well as inhibitors of their synthesis, reduce the LTs actions: bronchoconstriction, bronchial hyperresponsiveness, hypersecretion and inflammation. They produce an acute bronchodilating effect in mild asthma, reduce the hyperresponsiveness responses due to allergens, aspirin and cold and dry air, and also cutaneous and gastrointestinal reactions. Oral administrations tested during 4 or 6 weeks diminish the use of the beta-agonists, decrease the asthma symptom scores and other inflammatory signs.

PERSPECTIVES AND PROJECTS

More studies for longer periods, double blind trials and comparisons with classical treatments will be necessary to define the real place of LTs antagonists in the treatment of asthma. So their efficacy has to be confirmed as well as their good tolerance profile (particularly for hepatic functions).

CONCLUSION

Antagonists of receptors and synthesis inhibitors of LTs have known a recent and important development. They constitute a new therapeutic class: further studies are needed to better define the place of these new drugs in the treatment of asthma and other inflammatory diseases.

Effect of temafloxacin on the pharmacokinetics of theophylline

A number of fluoroquinolones have been shown to interact adversely with theophylline. We studied the influence of coadministration of temafloxacin, a new fluoroquinolone antimicrobial agent, on steady-state theophylline pharmacokinetics. Twelve healthy subjects (8 males, 4 females; average age and weight 34 years and 62 kg, respectively) were given oral controlled-release theophylline in an individualized dosage to achieve a target plasma level of 10 mg/L. Once steady state was achieved, temafloxacin 600 mg given orally twice daily was concomitantly administered for 4-5 days. Serial blood samples were collected before and during simultaneous temafloxacin administration and plasma assayed for theophylline using a high-performance liquid chromatography technique. Theophylline pharmacokinetic parameters were determined noncompartmentally, and results of single and combined administration were compared. Theophylline plasma concentrations did not differ significantly with temafloxacin coadministration, and similar area-under-the-curve (AUC) values were observed. Theophylline oral clearance increased from 2.67 +/- 1.01 L/hour to 2.69 +/- 0.93 L/hour, when given alone and with temafloxacin, respectively (p = 0.92). Only 2 of 12 subjects showed an appreciable decrease in clearance when theophylline and temafloxacin were administered together, while 2 subjects demonstrated increases greater than 15% and 8 showed no change. We conclude that temafloxacin does not interact significantly with theophylline and that these agents can be safely administered together.