Improved objective Bayesian estimator for a PLP model hierarchically represented subject to competing risks under minimal repair regime.

In this paper, we propose a hierarchical statistical model for a single repairable system subject to several failure modes (competing risks). The paper describes how complex engineered systems may be modelled hierarchically by use of Bayesian methods. It is also assumed that repairs are minimal and each failure mode has a power-law intensity. Our proposed model generalizes another one already presented in the literature and continues the study initiated by us in another published paper. Some properties of the new model are discussed. We conduct statistical inference under an objective Bayesian framework. A simulation study is carried out to investigate the efficiency of the proposed methods. Finally, our methodology is illustrated by two practical situations currently addressed in a project under development arising from a partnership between Petrobras and six research institutes.

Randomized trial to evaluate azithromycin's effects on serum and upper airway IL-8 levels and recurrent wheezing in infants with respiratory syncytial virus bronchiolitis.

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis in infancy is a major risk factor for recurrent wheezing and asthma. Because azithromycin attenuated neutrophilic airway inflammation in a murine viral bronchiolitis model, demonstration of similar effects in human subjects might provide a strategy for the prevention of postbronchiolitis recurrent wheezing. OBJECTIVES: We sought to investigate whether azithromycin treatment during RSV bronchiolitis reduces serum and nasal lavage IL-8 levels and the occurrence of postbronchiolitis recurrent wheezing. METHOD: We performed a randomized, double-masked, placebo-controlled proof-of-concept trial in 40 otherwise healthy infants hospitalized with RSV bronchiolitis who were treated with azithromycin or placebo for 14 days. IL-8 levels were measured in nasal lavage fluid and serum on randomization, day 8, and day 15 (nasal lavage only). The occurrence of wheezing episodes was assessed monthly over the ensuing 50 weeks. RESULTS: Compared with placebo, azithromycin treatment did not reduce serum IL-8 levels at day 8 (P = .6) but resulted in a greater decrease in nasal lavage fluid IL-8 levels by day 15 (P = .03). Twenty-two percent of azithromycin-treated participants experienced at least 3 wheezing episodes compared with 50% of participants in the placebo group (P = .07). Azithromycin treatment resulted in prolonged time to the third wheezing episode (P = .048) and in fewer days with respiratory symptoms over the subsequent year in comparison with placebo (36.7 vs 70.1 days, P = .01). CONCLUSION: In this proof-of-concept study azithromycin treatment during RSV bronchiolitis reduced upper airway IL-8 levels, prolonged the time to the third wheezing episode, and reduced overall respiratory morbidity over the subsequent year.

Attachment of carbohydrates to methoxyaryl moieties leads to highly selective inhibitors of the cancer associated carbonic anhydrase isoforms IX and XII.

The transmembrane isoforms of carbonic anhydrase (hCA IX and XII) have been shown to be linked to carcinogenesis and their inhibition to arrest primary tumor and metastases growth. In this paper, we present a new class of C-glycosides incorporating the methoxyaryl moiety, that was designed to selectively target and inhibit the extracellular domains of the cancer-relevant CA isozymes. The glycosides have been prepared by aldol reaction of glycosyl ketones with the appropriate aromatic aldehydes. We also present the inhibition profile of our new glycomimetics, against four isozymes of carbonic anhydrase comprising hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (tumor associated isozymes). In this study, per-O-acetylated glycoside 4, 6 and deprotected compounds 7, 9, 10 and 12 were identified as potent and highly selective inhibitors of hCA IX and XII. These results confirm that attaching carbohydrate moieties to CA methoxyaryl pharmacophore improves and enhances its inhibitory activity. These CA inhibitors have developmental potential to selectively target cancer cells, leading to cell death.

Sources of methodological variability in phase angles from respiratory inductance plethysmography in preterm infants.

RATIONALE: Better phenotypic descriptions are needed for chronic lung disease among surviving premature infants. OBJECTIVES: The purpose of this study was to evaluate the potential usefulness of respiratory inductance plethysmography in characterizing respiratory system mechanics in preterm infants at 32 weeks postmenstrual age. METHODS: Respiratory inductance plethysmography was used to obtain the phase angle, Φ, to describe rib cage and abdominal dyssynchrony in 65 infants born between 23 and 28 weeks gestation, all of whom were studied at 32 weeks postmenstrual age. Up to 60 breaths were evaluated for each subject. Sources of intrasubject variability in Φ arising from our methods were explored using mechanical models and by evaluating interobserver agreement. MEASUREMENTS AND MAIN RESULTS: The mean Φ from infants ranged from 5.8-162.9°, with intrasubject coefficients of variation ranging from 11-123%. On the basis of the mechanical model studies, respiratory inductance plethysmography recording and analysis software added <2.3% to the intrasubject variability in Φ. Potential inconsistencies in breaths selected could have contributed 8.1%, on average, to the total variability. The recording sessions captured 22.8 ± 9.1 minutes of quiet sleep, and enough breaths were counted to adequately characterize the range of Φ in the session. CONCLUSION: Φ is quite variable during even short recording sessions among preterm infants sleeping quietly. The intrasubject variability described herein arises from the instability of the rib cage and abdominal phase relationship, not from the recording and analytical methods used. Despite the variability, Φ measurements allowed the majority (80%) of infants to be reliably categorized as having relatively synchronous or dyssynchronous breathing. Respiratory inductance plethysmography is easy to use and should prove useful in quantifying respiratory mechanics in multicenter studies of preterm infants.

Inhibition of the ß-carbonic anhydrases from Mycobacterium tuberculosis with C-cinnamoyl glycosides: identification of the first inhibitor with anti-mycobacterial activity.

A small series of C-cinnamoyl glycoside containing the phenol moiety was tested for the inhibition of the three Mycobacterium tuberculosis ß-carbonic anhydrases (CAs, EC 4.2.1.1) with activities in the low micromolar range detected. The compounds were also tested for the inhibition of growth of M. tuberculosis H(37)Rv strain, leading to the identification of (E)-1-(2',3',4',6'-tetra-O-acetyl-ß-D-glucopyranosyl)-4-(3-hydroxyphenyl)but-3-en-2-one (1) as the first carbonic anhydrase inhibitor with anti-tubercular activity.

Synthesis of C-cinnamoyl glycosides and their inhibitory activity against mammalian carbonic anhydrases.

A small series of C-cinnamoyl glycosides incorporating the phenol moiety has been prepared by reaction of glycosyl ketones with the appropriate benzaldehydes. Glycosides were tested for the inhibition of twelve mammalian isoforms of carbonic anhydrase. This is the first study in which α-CAs have been investigated for their interaction with C-glycosides, a novel carbohydrate scaffold in the design of carbonic anhydrase inhibitors. The C-cinnamoyl glycosides were generally effective CA inhibitors, with inhibition constants in the low micromolar range against CA I, II, IV, VA, VB, VI, VII, IX, XII, XIII, XIV and ineffective inhibitors of CA III. These results confirm that attaching carbohydrate moieties to CA phenol pharmacophore improves its inhibitory activity.

Conformational behavior of peracetylated ß-D-mannopyranosyl methanesulfonamide: implications for the mechanism of sulfonamidoglycosylation of carbohydrate derivatives.

The conformational behavior of 2,3,4,6-tetra-O-acetyl-ß-D-mannopyranosyl methanesulfonamide has been investigated from a combined theoretical and experimental point of view. The study of the conformational space of the glycosyl sulfonamide revealed that the ß anomer is thermodynamically more stable than the α one. This fact suggests that the synthesis reaction could take place mainly under thermodynamic control as the main experimental product is the ß-anomeric form of the sulfonamide. Several intramolecular hydrogen bonds were found in the stable conformers of the N-mannopyranosyl sulfonamide under study. A relationship was found to exist between them and the relative stability of the conformers. A detailed analysis of geometrical parameters shed light into the nature of the solid state structure of the novel 2,3,4,6-tetra-O-acetyl-ß-D-mannopyranosyl methanesulfonamide in terms of exo- and endo-anomeric effects and antiperiplanar relationships. NBO calculations confirmed those findings. Calculated (1)H and (13)C NMR chemical shifts support previous findings concerning configuration and conformation assignments of the title sulfonamide. Finally, an explanation of the stereochemical outcome of sulfonamidoglycosylations, was given in terms of exo- and endo-anomeric effects and steric factors.

N-ß-glycosyl sulfamides are selective inhibitors of the cancer associated carbonic anhydrase isoforms IX and XII.

The transmembrane isoforms of carbonic anhydrase (CA IX and XII) have been shown to be linked to carcinogenesis and their inhibition to arrest primary tumor and metastases growth. In this Letter, we present a series of peracetylated and deprotected N-ß-glycosyl sulfamides that were tested for the inhibition of 4 carbonic anhydrase isoforms: the cytosolic hCA I and hCA II and transmembrane tumor-associated IX and XII. Compounds 1-4 and 6-8 selectively target cancer-associated CAs (IX and XII) with K(I)s in the low nanomolar range.