PubMed · 1777078
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D Chadwick. 1991. Gabapentin.. https://pubmed.ncbi.nlm.nih.gov/1777078/
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BACKGROUND: Oral leukotriene receptor antagonists have been shown to have efficacy in chronic asthma. OBJECTIVE: To compare the clinical benefit of montelukast, a once-daily oral leukotriene receptor antagonist; placebo; and inhaled beclomethasone. DESIGN: Randomized, double-blind, double-dummy, placebo-controlled, parallel-group, 12-week study. SETTING: 36 sites worldwide. PATIENTS: 895 patients 15 to 85 years of age with chronic asthma and an FEV1 50% to 85% of predicted. INTERVENTIONS: Montelukast, 10 mg once daily at bedtime; inhaled beclomethasone, 200 microg twice daily, administered with a spacer device; or placebo. MEASUREMENTS: Primary end points were daytime asthma symptom score and FEV1. Secondary end points were peak expiratory flow rates in the morning and evening, as-needed beta-agonist use, nocturnal awakenings, asthma-specific quality of life, and worsening asthma episodes. RESULTS: Over the 12-week treatment period, the average percentage change from baseline in FEV1 was 13.1% with beclomethasone, 7.4% with montelukast, and 0.7% with placebo (P < 0.001 for each active treatment compared with placebo; P < 0.01 for beclomethasone compared with montelukast). The average change from baseline in daytime symptom score was -0.62 for beclomethasone, -0.41 for montelukast, and -0.17 for placebo (P < 0.001 for each active treatment compared with placebo; P < 0.01 for beclomethasone compared with montelukast). Each agent improved peak expiratory flow rates and quality of life, reduced nocturnal awakenings and asthma attacks, increased the number of asthma-control days, and decreased the number of days with asthma exacerbations (P < 0.001 for each active treatment compared with placebo for each end point; P < 0.01 for beclomethasone compared with montelukast for each end point). Although beclomethasone had a greater mean clinical benefit than montelukast, montelukast had a faster onset of action and a greater initial effect. The two agents caused similar decreases in peripheral blood eosinophil counts (P < 0.05 for each agent compared with placebo). Both agents had tolerability profiles similar to that of placebo over the 12-week study. CONCLUSIONS: Although beclomethasone had a larger mean effect than montelukast, both drugs provided clinical benefit to patients with chronic asthma. This finding is consistent with the use of these agents as controller medications for chronic asthma.
Under a variety of conditions, the permeability of the inner mitochondrial membrane to small solutes can be nonselectively increased. A classic mitochondrial permeability transition (MPT) was originally identified based on its dependence on matrix Ca2+ and its extreme sensitivity to cyclosporin A (CsA). It is now clear, however, that several additional and distinct processes can also produce increases in mitochondrial permeability. Both mitochondrial signal peptides (P. M. Sokolove and K. W. Kinnally, 1996, Arch. Biochem. Biophys. 336, 69-76) and butylated hydroxytoluene (BHT) (P. M. Sokolove and L. M. Haley, 1996, J. Bioenerg. Biomembr. 28, 199-206), for example, induce permeability increases that are relatively CsA insensitive and that persist in the presence of EGTA. Inorganic phosphate (Pi) appears to play a key role in each of these permeability increases. High (>1 mM) Pi levels facilitate the classic MPT, while Pi concentrations below 1 mM stimulate the permeability increase induced by signal peptides and inhibit that triggered by BHT. The effect of high Pi concentrations can most probably be explained by exchange of the anion for matrix ADP and the resulting alleviation of ADP-mediated inhibition of the MPT (R. G. Lapidus and P. M. Sokolove, 1994, J. Biol. Chem. 269, 18931-18936). In the experiments reported here, the mechanisms underlying the effects of low Pi concentrations on mitochondrial permeability were investigated, by monitoring mitochondrial volume, with the following results: (1) A hitherto unrecognized ability of Pi (<1 mM) to increase the lag preceding induction of the classic MPT by diamide, phenylarsine oxide, and t-butylhydroperoxide was identified. (2) Data were obtained suggesting that all of the effects of low Pi concentration, stimulation of signal peptide-induced swelling, blockade of BHT-induced swelling, and delay of the classic MPT, can be attributed to the capacity of the anion to complex Ca2+ in the mitochondrial matrix. (3) Differences in the responses of these three systems for enhancing mitochondrial permeability to experimental manipulation indicate that matrix Ca2+ plays more than one role in the regulation of mitochondrial permeability. An additional important finding is the observation that failure of EGTA to alter a mitochondrial process need not mean that the process is Ca2+ independent. In a multicompartment system, absence of EGTA action may instead reflect failure of the chelator to gain access to regulatory Ca2+.
The polyketide antibiotic TA is synthesized by the Gram negative bacterium Myxococcus xanthus in a multi-step process in which a unique glycine-derived molecule is used as a starter unit and elongated through the condensation of 11 acetate molecules by polyketide synthases (PKSs). Analysis of a 7.2 kb DNA fragment, encoding the protein that carries out the first condensation step, revealed that the fragment constitutes a single open reading frame, referred to as Ta1, which lacks the 5' and 3' ends and displays two regions of similarity to other proteins. The first 1020 amino acid residues at the N terminus of the polypeptide are similar to sequences of the large family of enzymes encoding peptide synthetases. They are followed by a second region displaying a high degree of similarity to type I PKS genes. The genetic analysis of this open reading frame is compatible with the proposed chemical structure of TA. The data indicate that the genes encoding TA have a modular gene organization, typical of a type I PKS system. The unusual feature of Ta1 is that the first PKS module of TA resides on the same polypeptide as the peptide synthetase functional unit.