A multicenter evaluation of sweat chloride concentration and variation in infants with cystic fibrosis.

Fifty-nineCF infants' sweat chloride concentrations were analyzed to answer the questions: What is the biological and analytical variation in sweat chloride concentrations collected from the 32 infants homozygous for the F508 deletion? Do sweat chloride concentrations change in the first year of life beyond the variance previously established for adults with similar CFTR mutations? The biological and analytical variation of the infants' sweat chloride concentration was similar to that seen in adult CF patients. While there was a statistically significant difference between sweat chloride concentration in early (89.8 mmol/L) and late (95.0 mmol/L) infancy, this change is not likely clinically significant. This suggests that sweat chloride concentrations in CF patients do not change in a meaningful way during the first year of life. Determining variability in infants with CF is the necessary first step for future design of clinical trials of CFTR modulators in younger patients.

Analytical and biological variation in repeated sweat chloride concentrations in clinical trials for CFTR modulator therapy.

BACKGROUND: Using sweat chloride as a biomarker for CFTR modifying drugs requires knowledge of analytical and biological variation. METHODS: 979 sweat chloride concentrations from 128 subjects enrolled in the placebo arm of 2 multicenter, investigational drug trials were analyzed to determine coefficients of variation (CV) as well as reference change value (RCV) and index of individuality (II). RESULTS: For these populations, calculated values for the two studies were: analytical variation (3.9, 4.1%); within-subject variation (4.4, 6.0%); between-subject variation (8.9, 7.0%); RCV (13.7, 17.0%) and II (0.7, 1.0). Sweat chloride variation was not affected by sex, collection site or sample weight; but was slightly affected by age in one of the two studies. CONCLUSION: Through determination of analytical as well as between- and within-subject variation, and with a larger sample size, our data allows improved estimates of the RCV and II, and can contribute to future trials of CFTR modulators and inform the design and interpretation of n of 1 trials in both research and clinical settings.

Advances in mast cell biology: new understanding of heterogeneity and function.

Mast cells are classically viewed as effector cells of IgE-mediated allergic diseases. However, over the last decade our understanding has been enriched about their roles in host defense, innate and adaptive immune responses, and in homeostatic responses, angiogenesis, wound healing, tissue remodeling, and immunoregulation. Despite impressive progress, there are large gaps in our understanding of their phenotypic heterogeneity, regulatory mechanisms involved, and functional significance. This review summarizes our knowledge of mast cells in innate and acquired immunity, allergic inflammation and tissue homeostasis, as well as some of the regulatory mechanisms that control mast cell development, phenotypic determination, and function, particularly in the context of mucosal surfaces.

Detection and characterization of a type IIA secretory phospholipase A2 inhibitory protein in human amniotic fluid.

Two types of phospholipase A2 (PLA2) inhibitory protein (PLIP-I, PLIP-II) were detected and isolated from human amniotic fluid by Sephacryl S300 gel filtration chromatography. The lower molecular weight-fraction (PLIP-II) was further purified by Sephadex G75 gel filtration and analyzed by SDS-PAGE. Its molecular weight was estimated to be approximately 18 kDa, and it was sensitive to heat treatment. Inhibition of phospholipase A2 (sPLA2 type IIA) by PLIP-II occurred in a dose-dependent manner (IC50 about 0.82/microm), and the effect was stronger on sPLA2 IIA than on pancreatic sPLA2 (IC50 about 3.11 microL). The ratio of the inhibitions of the sPLA2 IIA by PLIP-II remained consistent over an entire range of substrate concentrations. Furthermore, addition of excess Ca2+ at concentrations of up to 10 mm did not antagonize the inhibitory activity of PLIP-II.

Synthesis and biological acitivity of annulated pyrazoles as selective COX-2 inhibitors. I.

A series of disubstituted 4,5-polymethylenepyrazoles were synthesized and evaluated their inhibitory activities against COX-2. Some compounds showed strong (0.3 nM) inhibitory activity on COX-2 and were found somewhat selective (up to 16) on COX-2 over COX-1.

Pinusolide from the leaves of Biota orientalis as potent platelet activating factor antagonist.

We investigated the effect of a new PAF antagonist pinusolide, isolated from the leaves of Biota orientalis, on PAF-induced [3H]serotinin release from rabbit platelets, hypotension and vascular permeability. Pinusolide (IC50, about 5 x 10(-6) M) inhibited specifically [3H]serotinin release from rabbit platelets when stimulated with PAF (5 x 10(-8) M), but showed no effect when induced by ADP, collagen, and thrombin. It also inhibited PAF-induced hypotension in a dose-dependent manner in rats with no effect on the hypotension induced by acetylcholine, histamine and serotonin. The inhibitory effect of pinusolide on the PAF-induced vascular permeability is less specific than the induced hypotension. These results suggest that pinusolide may prove of therapeutic value in the treatment of hypotension and a molecular design of pinusolide analogues may provide the possibility of a new PAF specific antagonists.

A new class of COX-2 inhibitor, rutaecarpine from Evodia rutaecarpa.

OBJECTIVE AND DESIGN: We investigated the effect of a new class of COX-2 inhibitor, rutaecarpine, on the production of PGD2 in bone marrow derived mast cells (BMMC) and PGE2 in COX-2 transfected HEK293 cells. Inflammation was induced by lambda-carrageenan in male Splague-Dawley (SD) rats. MATERIAL: Rutaecarpine (8,13-Dihydroindolo[2',3':3,4]pyridol[2,1-b]quinazolin -5(7H)-one) was isolated from the fruits of Evodia rutaecarpa. BMMC were cultured with WEHI-3 conditioned medium. c-Kit ligand and IL-10 were obtained by their expression in baculovirus. METHODS: The generation of PGD2 and PGE2 were determined by their assay kit. COX-1 and COX-2 protein and mRNA expression was determined by BMMC in the presence of KL, LPS and IL-10. TREATMENT: Rutaecarpine and indomethacin dissolved in 0.1% carboxymethyl cellulose was administered intraperitoneally and, 1 h later, lambda-carrageenan solution was injected to right hind paw of rats. Paw volumes were measured using plethysmometer 5 h after lambda-carrageenan injection. RESULTS: Rutaecarpine inhibited COX-2 and COX-1 dependent phases of PGD2 generation in BMMC in a concentration-dependent manner with an IC50 of 0.28 microM and 8.7 microM, respectively. It inhibited COX-2-dependent conversion of exogenous arachidonic acid to PGE2 in a dose-dependent manner by the COX-2-transfected HEK293 cells. However, rutaecarpine inhibited neither PLA2 and COX-1 activity nor COX-2 protein and mRNA expression up to the concentration of 30 microM in BMMC, indicating that rutaecarpine directly inhibited COX-2 activity. Furthermore, rutaecarpine showed in vivo anti-inflammatory activity on rat lambda-carrageenan induced paw edema by intraperitoneal administration. CONCLUSION: Anti-inflammatory activity of Evodia rutaecarpa could be attributed at least in part by inhibition of COS-2.

Regulation of cyclooxygenase-2 and endogenous cytokine expression by bacterial lipopolysaccharide that acts in synergy with c-kit ligand and Fc epsilon receptor I crosslinking in cultured mast cells.

Emerging evidence has suggested the pivotal role of mast cells in a host defense against bacterial infection. In this paper, we report that bacterial lipopolysaccharide (LPS) is a potent enhancer of the cytokine- and IgE-dependent delayed responses of IL-3-dependent mouse bone marrow-derived cultured mast cells (BMMC). LPS, although showing minimal effects, significantly augmented the c-kit ligand (KL)- or IgE-dependent expression of cyclooxygenase (COX)-2 and the attendant delayed PGD2 generation, with IL-10 and IL-4 acting as potentiating and inhibitory cytokines, respectively. The COX-2-inducing activity of LPS was mimicked by exogenous IL-1 beta. Assessment of endogenous cytokine induction revealed that IL-1 beta expression was stimulated by either LPS or exogenous IL-1 beta. IL-6 expression occurred in parallel with COX-2 expression. IL-10 expression, which lagged behind COX-2 expression, depended on exogenous IL-10, but not on LPS and IL-1 beta. Thus, LPS and IL-1 beta exhibited similar biological activities in terms of COX-2 and endogenous cytokine expression. However, adding an antibody against the type I IL-1 receptor to BMMC, which abrogated the effects of IL-1 beta, failed to neutralize the effects of LPS. These results suggest that LPS activates BMMC through the signal transduction pathway shared with exogenous IL-1 beta, rather than exerting its action indirectly via the production of endogenous IL-1 beta.