Search

Persistent airflow limitation (PAL) occurs in a subset of patients with asthma. Previous studies on PAL in asthma have included relatively small populations, mostly restricted to severe asthma, or have no included longitudinal data. The aim of this post-hoc analysis was to investigate the determinants, clinical implications, and outcome of PAL in patients with asthma who were included in the ATLANTIS study.

Although estimates of suboptimal adherence to oral corticosteroids in asthma range from 30% to 50%, no ideal method for measurement exists; the impact of poor adherence in severe asthma is likely to be particularly high.

Unlabelled Boxce:textbox-body/

Recently, we demonstrated that losartan reduced the aortic root dilatation rate (AoDR) in adults with Marfan syndrome (MFS); however, responsiveness was diverse. The aim was to determine the role of transforming growth factor-β (TGF-β) as therapeutic biomarker for effectiveness of losartan on AoDR. Baseline plasma TGF-β levels of 22 healthy controls and 99 MFS patients, and TGF-β levels after 1 month of losartan treatment in 42 MFS patients were measured. AoDR was assessed by magnetic resonance imaging at baseline and after 3 years of follow-up. Patients with MFS had higher TGF-β levels compared with healthy controls (121 pg/ml versus 54 pg/mL, p= 0.006). After 1 month of therapy, losartan normalised the TGF-β level in 15 patients (36%); the other 27 patients (64%) showed a significant increase of TGF-β. After 3 years of losartan therapy, patients with a decrease in TGF-β had significantly higher AoDR compared with patients with increased TGF-β (1.5 mm/3 years versus 0.5 mm/3 years, p= 0.04). Patients showing a decrease in TGF-β after losartan therapy had significantly elevated baseline TGF-β levels compared with patients with increased TGF-β (189 pg/ml versus 94 pg/ml, p= 0.05). Patients responding to losartan therapy with a reduction of the plasma TGF-β level had higher baseline TGF-β levels and a higher AoDR. Most likely, TGF-β levels may be considered to be a readout of the disease state of the aorta. We propose that increased angiotensin II is the initiator of aorta dilatation and is responsible for increased TGF-β levels in MFS. The concept of TGF-β as initiator of aortic dilatation in MFS patients should be nuanced.

We report on “safe” Coulomb excitation of neutron-rich 138,140,142Xe nuclei. The radioactive nuclei have been produced by ISOLDE at CERN and post-accelerated by the REX-ISOLDE facility. The γ-rays emitted by the decay of excited states have been detected by the MINIBALL array. Recent results are presented.

A new reagent, DPSgt, is described which has been designed to label cell surface proteins at 0 degree C. The reagent is easily made; it is water soluble and contains a reactive impermeant ester at one end, a tyrosine which can be radioiodinated at the other, and a disulphide in‐between. The label can be removed from cells by cleaving the disulphide linkage in it with glutathione at 0 degree C. When cells are warmed to 37 degrees C between labelling and reduction, labelled proteins which are endocytosed acquire resistance to reduction. This provides a simple way of measuring the endocytosis of surface proteins. The intracellular pools of transferrin and LDL receptors in K562 cells and fibroblasts have been estimated. The results indicate that intracellular receptors are in non‐reducing compartments, and that uptake of average cell surface (by non‐coated pit processes) in K562 cells is small.

ATP synthase, the assembly which makes ATP in mitochondria, chloroplasts and bacteria, uses transmembrane proton gradients generated by respiration or photosynthesis to drive the phosphorylation of ADP. Its membrane domain is joined by a slender stalk to a peripheral catalytic domain, F1‐ATPase. This domain is made of five subunits with stoichiometries of 3 alpha: 3 beta: 1 gamma: 1 delta: 1 epsilon, and in bovine mitochondria has a molecular mass of 371,000. We have determined the 3‐dimensional structure of bovine mitochondrial F1‐ATPase to 6.5 A resolution by X‐ray crystallography. It is an approximately spherical globule 110 A in diameter, on a 40 A stem which contains two alpha‐helices in a coiled‐coil. This stem is presumed to be part of the stalk that connects F1 with the membrane domain in the intact ATP synthase. A pit next to the stem penetrates approximately 35 A into the F1 particle. The stem and the pit are two examples of the many asymmetric features of the structure. The central element in the asymmetry is the longer of the two alpha‐helices in the stem, which extends for 90 A through the centre of the assembly and emerges on top into a dimple 15 A deep. Features with threefold and sixfold symmetry, presumed to be parts of homologous alpha and beta subunits, are arranged around the central rod and pit, but the overall structure is asymmetric. The central helix provides a possible mechanism for transmission of conformational changes induced by the proton gradient from the stalk to the catalytic sites of the enzyme.

Crystals of the F1-ATPase sector of the ATP synthase complex from bovine heart mitochondria have been grown from solutions containing polyethylene glycol 6000. The crystals diffract to 2·9 Å resolution on a laboratory X-ray source. They are orthorhombic and belong to the space group P212121. The unit cell axes are a= 285 Å, b= 108 Å, c= 140 Å. There is one molecule of F1-ATPase in the asymmetric unit.

A new procedure for the isolation of ATP synthase from bovine mitochondria has been developed, with the primary objective of producing enzyme suitable for crystallization trials. Proteins were extracted from mitochondrial membranes with dodecyl-beta-D-maltoside, and the ATP synthase was purified from the extract in the presence of the same detergent by a combination of ion-exchange and gel-filtration chromatography and ammonium sulphate precipitation. This simple and rapid procedure yields 20-30 mg of highly pure and monodisperse enzyme, evidently consisting of 14 different subunits, amongst them, in apparently stoichiometric amounts with the established subunits, subunit e, a recently discovered subunit of unknown function. The enzyme preparation has an oligomycin-sensitive ATP hydrolysis activity, and so the F1 domain is functionally associated with the membrane domain, F0. In contrast with the N-termini of some of the subunits of bovine mitochondrial F1-ATPase, those of the F1F0-ATP synthase are not degraded by proteolysis during the isolation procedure. This preparation therefore satisfies prerequisites for crystallization trials.

The following meanlives of levels in72Se have been measured using the recoildistance Doppler-shift method:?(2+, 862 keV)=3.1±0.6 ps,?(2+', 1317 keV)=12.5±2.6 ps,?(4+, 1638 keV)=1.2±0.3 ps and?(6+, 2469 keV)?0.7 ps. These meanlives yield sixB(E2) values which are discussed together with the known data of the depopulation of the excited 0+' state at 937 keV. Systematics of 0+' states in the mass region 70?A?100 show that the low excitation energy of the 0+' states is correlated with subshell closures. This suggests that the previous interpretation of the 0+' state in72Se as a rotational band head is questionable.

Polymorphonuclear leukocytes contain an oxidase system that can be activated to produce superoxide radicals and hydrogen peroxide. A nonmitochondrial b cytochrome, functioning in the generation of these oxygen species, has been purified to apparent homogeneity from human polymorphonuclear phagocytes. After solubilization of the cytochrome with Triton X-100, the cell extract was subsequently chromatographed on Blue Sepharose and Sephacryl S-300. The final preparation was maximally purified 170-fold with a specific content of 5.33 +/- 2.03 nmol mg-1 of protein (mean +/- S.D.; n = 7) and a yield of 21 +/- 13% (n = 5). The apparent molecular mass of the nondenatured cytochrome was estimated by gel filtration to be 235 kDa. Upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, a single polypeptide was found with a molecular mass of 127 kDa. From the pyridine hemochrome spectrum 1 protoheme IX/polypeptide was calculated. The light absorbance bands of the dithionite-reduced cytochrome were found to be at 558.5 (alpha), 529 (beta), and 426 nm (Soret), and that of the oxidized cytochrome at 413.5 nm. The difference absorbance coefficients are delta epsilon (426.5 - 440 nm) = 160.6 +/- 11 mM-1 cm-1 and delta epsilon (558.5 - 542 nm) = 29.3 +/- 2 mM-1 cm-1 (mean +/- S.D.; n = 5). Carbon monoxide binds to the cytochrome in a time-dependent fashion (maximum binding after 50-60 min). The midpoint potential of the solubilized nonpurified cytochrome is identical to the cytochrome in situ (Em7.0 = -218 +/- 7 mV (mean +/- S.D.; n = 5)). However, purified cytochrome b shows a significantly decreased midpoint potential, estimated at -407 +/- 18 mV (n = 4). The protein does not contain noncovalently bound FAD or FMN, and no spectral evidence was obtained for the presence of covalently bound flavin. Preliminary amino acid analysis of the cytochrome shows a high content of hydrophilic residues.

The sequences of the genes for the nine subunits of ATP synthase in the thermophilic cyanobacterium Synechococcus 6716 have been determined. The genes were identified by comparison of the encoded proteins with sequences of ATP synthase subunits in other species, and confirmed for subunits alpha, beta, delta and epsilon, by determining their N-terminal sequences. They are arranged at three separate loci. Six of them are in one cluster in the order a: c: b': b: delta: alpha, and those for the beta and epsilon subunits form a second and separate cluster. The gene for the gamma-subunit is at a third site. As in other bacteria, the gene for subunit a is immediately preceded by a gene coding for a small hydrophobic protein of unknown function, known as uncI in Escherichia coli. The gene orders in Synechococcus 6716 are related to the orders of ATP synthase genes in the plastid genomes of higher plants, and particularly of a red alga and a diatom. The sequences of the subunits are similar to those of chloroplast ATP synthase, the alpha, beta and c subunits being particularly well conserved. Differences in the primary structures of the Synechococcus 6716 and chloroplast gamma subunits probably underlie different mechanisms of activation of ATP synthase. The nucleotide sequences that are presented also contain 12 other open reading frames. One of them encodes a protein sequence related to the E. coli DNA repair enzyme, photolyase, and another codes for a protein that contains internal repeats related to sequences in the myosin heavy chain.

The static quadrupole moment of the first excited 2+ state in32S was determined by comparing, in coincidence with32S ions backscattered from60Ni, the gamma-ray yields of the 21+?01+ transitions in both nuclei for bombarding energies around 70MeV. Depending on the sign of the interference term for transitions via the second excited 2+ state in32S, the following two values were determined:Q2+=(-18±4)e·fm2 andQ2+=(-15±4)e·fm2.

In crude extracts of primary leaves from dark grown seedlings of Phaseolus vulgaris L., relatively high hydrolytic activity of chlorophyllase (chlorophyll-chlorophyllido-hydrolase, EC 3.1.1.14) was observed. When plants were exposed to continuous illumination, the enzyme activity in the extracts was doubled within 3 days and both chlorophyll a and b were synthesized. However, when exposed to periodic illumination (1 min light-59 min dark) the enzyme activity was doubled within 1 to 2 days and chlorophyll a was synthesized but the formation of chlorophyll b was suppressed. When plants were transferred from periodic illumination to continuous illumination chlorophyll b was synthesized but the activity of chlorophyllase declined. Chloramphenicol blocked the increase in enzyme activity independent of the light regimes, but cycloheximide inhibited the activity more effectively during growth in the light. The presence of chlorophyllase activity in the leaves is discussed in relation to the chlorophyll-proteins and the membranes known to be present in chloroplasts. It is suggested that the enzyme is synthesized on plastid ribosomes.

Neutrophilic granulocytes contain an oxidase system in their plasma membrane that can be activated to generate superoxide radicals and hydrogen peroxide. Cytochrome b, flavoprotein, and ubiquinone-50 have been proposed as components of this oxidase system. These components have been quantitated, but the results are obscured by different isolation procedures for plasma membranes from resting and activated neutrophils. This problem has now been avoided by the use of enucleated neutrophils (polymorphonuclear leukocyte cytoplasts), which are almost completely devoid of intracellular structures but contain an intact, activatable oxidase system (Roos, D., Voetman, A.A., and Meerhof, L.J. (1983) J. Cell Biol. 97, 368-377). Membranes of resting and phorbol myristate acetate-stimulated cytoplasts contain equal amounts of cytochrome b (4 pmol/milliunit of alkaline phosphatase) and also equal amounts of noncovalently bound FAD (2 pmol/milliunit of alkaline phosphatase). These findings refute the hypothesis that incorporation of cytochrome b and/or a flavoprotein into the plasma membrane constitutes the mechanism of activation of the oxidase system. Ubiquinone-50 is present neither in intact neutrophils nor in cytoplasts, excluding a role for this compound in the generation of bactericidal oxygen species by neutrophils.

Abstract.: We report on “safe” Coulomb excitation of neutron-rich 138,140,142Xe nuclei. The radioactive nuclei have been produced by ISOLDE at CERN and post-accelerated by the REX-ISOLDE facility. The γ-rays emitted by the decay of excited states have been detected by the MINIBALL array. Recent results are presented.

We report on ?safe? Coulomb excitation of neutron-rich 138,140,142Xe nuclei. The radioactive nuclei have been produced by ISOLDE at CERN and post-accelerated by the REX-ISOLDE facility. The ?-rays emitted by the decay of excited states have been detected by the MINIBALL array. Recent results are presented. ?