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.

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.

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.