Many lung disease processes are characterized by structural and functional heterogeneity that is not directly appreciable with traditional physiological measurements. Experimental methods and lung function modeling to study regional lung function are crucial for better understanding of disease mechanisms and for targeting treatment. Synchrotron radiation offers useful properties to this end: coherence, utilized in phase-contrast imaging, and high flux and a wide energy spectrum which allow the selection of very narrow energy bands of radiation, thus allowing imaging at very specific energies. K-edge subtraction imaging (KES) has thus been developed at synchrotrons for both human and small animal imaging. The unique properties of synchrotron radiation extend X-ray computed tomography (CT) capabilities to quantitatively assess lung morphology, and also to map regional lung ventilation, perfusion, inflammation and biomechanical properties, with microscopic spatial resolution. Four-dimensional imaging, allows the investigation of the dynamics of regional lung functional parameters simultaneously with structural deformation of the lung as a function of time. This review summarizes synchrotron radiation imaging methods and overviews examples of its application in the study of disease mechanisms in preclinical animal models, as well as the potential for clinical translation both through the knowledge gained using these techniques and transfer of imaging technology to laboratory X-ray sources. 相似文献
1. 1.In young pigs living at 35 or 10°C on a high or low energy intake, respiratory enzyme activities in longissimus dorsi muscle were greater both in the cold and on low intake. The elevated activities in the cold were unlikely to be related entirely to shivering since they were also found in muscle from the diaphragm.
2. 2.In a second study, pigs were kept close to thermal neutrality (26°C) on different levels of food intake and for different periods of time. For all animals, as body weight increased there was a decline in respiratory enzyme activity and the number of dark fibres in skeletal muscle. For those of the same weight, but different age and food intake, there was no difference in enzyme activity or number of dark fibres per unit area.
3. 3.At least part of the difference in respiratory enzyme activities related to energy intake must therefore be due to differences in body size. However, size is not the sole determinant of enzyme activity in skeletal muscle, since in animals of similar size those living at 10°C have greater enzyme activities than those at 35°C.
The respiratory system of chemolithoautotrophically-grown Alcaligenes latus contains a, b, and c type cytochromes. Two cytochrome oxidases were identified by their carbon monoxide difference spectra and their differing sensitivities to cyanide and carbon monoxide. The oxidases were cytochrome o and an a-type cytochrome. Ubiquinone was present in A. latus membranes and could be reduced by H2. The quinone analogue, 2-heptyl-4-hydroxy-quinoline-N-oxide (HQNO), was a strong inhibitor of the H2 oxidase reaction, but did not prevent the reduction of either ubiquinone or the cytochromes.Abbreviations HQNO
2-heptyl-4-hydroxy-quinoline-N-oxide
- TMPD
N,N,N,N-tetramethyl-p-phenylenediamine 相似文献
We developed a kinetic assay using a monolayer of differentiated respiratory epithelium in culture to assess bacterial adherence. Mean residence time of bacteria in the tissue culture chamber was estimated from a model-independent (moment) analysis of the rate of bacterial washout from perfused Rose chambers. Results with this method compared favorably with visual assessment of adherence and double radiolabel method with H. influenzae. Adherence was assessed with low inoculae of H. influenzae, P. cepacia and P. aeruginosa avoiding cytotoxic effects seen when large inoculae are added to eukaryotic cells. This method will provide a means of assessing adherence of pathogenic respiratory bacteria to their cellular target at low inoculae. 相似文献
We examined the effects of the recombinant human colony stimulating factors GM-CSF and G-CSF, cycloheximide (a protein synthesis inhibitor) and dihydrocytochalasin B (a microfilament disrupting agent) upon FMLP (N-formyl-methionyl-leucylphenylalanine)-stimulated O2− production by neutrophils. We confirmed a time dependent augmentation of O2− production following preincubation of neutrophils either alone or with colony stimulating factors. Furthermore, we found that GM-CSF, but not G-CSF, increased O2− production at some concentrations of the stimulus. Preincubation of neutrophils with cycloheximide in the absence of CSF caused a marked fall in O2−-production that was first evident at 2 hours. The fall in O2−-forming capacity caused by cycloheximide was much less pronounced if dihydrocytochalasin B was also included in the preincubation buffer. These findings suggest a previously unrecognized role for de novo protein synthesis in maintaining the ability of neutrophils to manufacture O2−, and support earlier studies indicating that the cycling of FMLP receptors between the cell membrane and an intracellular compartment is important in determining the magnitude of the respiratory burst in FMLP-stimulated neutrophils. 相似文献
Recently, we have shown that an untrained respiratory system does limit the endurance of submaximal exercise (64% peak oxygen consumption) in normal sedentary subjects. These subjects were able to increase breathing endurance by almost 300% and cycle endurance by 50% after isolated respiratory training. The aim of the present study was to find out if normal, endurance trained subjects would also benefit from respiratory training. Breathing and cycle endurance as well as maximal oxygen consumption (VO2max) and anaerobic threshold were measured in eight subjects. Subsequently, the subjects trained their respiratory muscles for 4 weeks by breathing 85-160 l.min-1 for 30 min daily. Otherwise they continued their habitual endurance training. After respiratory training, the performance tests made at the beginning of the study were repeated. Respiratory training increased breathing endurance from 6.1 (SD 1.8) min to about 40 min. Cycle endurance at the anaerobic threshold [77 (SD 6) %VO2max] was improved from 22.8 (SD 8.3) min to 31.5 (SD 12.6) min while VO2max and the anaerobic threshold remained essentially the same. Therefore, the endurance of respiratory muscles can be improved remarkably even in trained subjects. Respiratory muscle fatigue induced hyperventilation which limited cycle performance at the anaerobic threshold. After respiratory training, minute ventilation for a given exercise intensity was reduced and cycle performance at the anaerobic threshold was prolonged. These results would indicate the respiratory system to be an exercise limiting factor in normal, endurance trained subjects. 相似文献
Thiobacillus tepidarius (type strain) was grown in microaerophilic conditions, on tetrathionate, thiosulfate or crystalline So. The rates of tetrathionate, thiosulfate, elemental sulfur (So) and sulfite oxidation of the different cultures were measured respirometrically, using exponentially growing cells, with an oxygen electrode. Cells growing on the three different sulfur compounds retain thiosulfate-, tetrathionate, and So-oxidizing activities (SOA), but lack respiratory sulfite-oxidizing activity. The SOA for all the cultures was almost totally inhibited by 50 M myxothiazol, an inhibitor of the quinone-cytochrome b region, and by 10 M of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP). Tetrathionate- and thiosulfate-oxidizing activities were moderately and weakly inhibited by 50 M totally inhibited (>95%) all respiratory activities. This study suggests that electrons released by So oxidation enter the respiratory chain in the quinone-cytochrome b region.Abbreviation SOA
sulfur-oxidizing activity 相似文献
Summary The epithelium of the airways is rich in endocrine cells containing serotonin and/or a wide variety of regulatory peptides. These cells usually occur in clusters in the lungs but are also found scattered in the larynx and trachea. In the present study, endocrine cells in the airways of mouse, rat, hamster, guinea pig, pig, sheep and squirrel monkey were examined for the presence of serotonin, helodermin-like peptides and other regulatory peptides using immunocytochemistry and radioimmunoassay. In addition, we looked for the protein gene product 9.5 (PGP), which occurs in many peptide hormone-producing endocrine cells in the body. Both clustered and scattered endocrine cells in the airways were found to display coexistence of serotonin and peptides, such as a helodermin-like peptide, calcitonin and calcitonin gene-related peptide (CGRP). The PGP-immunoreactive cells were numerous and included elements containing serotonin and/or regulatory peptides. An additional PGP-immunoreactive endocrine cell population lacked serotonin and regulatory peptides. Helodermin-immunoreactive material was demonstrated in endocrine cells of the airways in the mouse and hamster but not in any of the other species studied. Serotonin was an endocrine cell constituent in all the species studied. Calcitonin and CGRP could be demonstrated by immunocytochemistry in the mouse, rat, and hamster, but not in the guinea pig, sheep, pig and monkey. In the hamster airways double immunostaining indicated that the helodermin-like peptide occurred in a subpopulation of the CGRP- and serotonin-containing cells. Most of the CGRP-containing cells stored serotonin; some of them also contained calcitonin. The chemical coding of these cells resembled that of the thyroid C cells. 相似文献