Measurement of static lung and thorax compliance in health and pulmonary diseases.
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Explore the source record for details and available documents.
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The aim of the present study was to define reference values for lung volumes and the lung transfer factor for carbon monoxide (TL,CO) for an adolescent population using thoracic volume index (TVI) and an index of pubertal stage in order to account for the variation in growth pattern between adolescents. TVI, pubertal stage by Tanner scale (PST), time since menarche, functional residual capacity measured using the helium-dilution technique, vital capacity, total lung capacity and TL,CO measured using a steady-state method were determined in 51 males (aged 13-20 yrs; PST T3-T5) and 52 females (aged 13-18 yrs; PST T2-T4; all but three had already undergone menarche). In male adolescents, height, weight, TVI, lung volumes and TL,CO increased with age. This was not the case in female adolescents. In males, the TVI was the independent variable that best correlated with pulmonary volumes. In females, height was the independent variable that best correlated with pulmonary volumes. In both sexes, the variable that best correlated with TL,CO was PST, associated with height in males. This cross-sectional study provides prediction equations for lung volumes and the lung transfer factor for carbon monoxide taking into account thoracic volume index and pubertal stage. It shows that, in adolescent males, lung and thoracic development occurs during and until the end of puberty. Conversely, in adolescent females, lung development is almost finished following menarche.
The purpose of the study was to evaluate the accuracy of magnetic resonance imaging (MRI) in detecting subclinical morphological changes caused by asbestos exposure. Conventional chest radiographs according to the International Labour Organisation (ILO) categories 0-11 and spirometric data were compared with MRI in 17 men with mean (+/-2SD) asbestos exposure time of 24.6+/-13.0 yrs. Mean age was 62.0+/-9.4 yrs. The inclusion criterion was an ILO score of 2 or more. Electrocardiographic registrations and antirespiratory movement artefact techniques were used in all MRI examinations to avoid movement artefacts. Mean ILO grading was found to be 7.7+/-3.8 on chest radiography and 9.8+/-2.0 with MRI (p=0.01). Five patients had a higher ILO stage as evaluated by MRI, but in nine patients the staging remained unchanged. MRI revealed mediastinal adenopathy in four patients. Forced expiratory volume in one second (expressed as a percentage of the predicted value) was negatively correlated with ILO score as assessed by MRI (r=-0.4, p=0.032). Magnetic resonance imaging seems to be more sensitive than conventional radiographs in detecting subclinical fibrosis as well as the extent of pleural asbestosis.
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The eyegone (eyg) gene is known to be involved in the development of the eye structures of Drosophila. We show that eyg and its related gene, twin of eyegone (toe), are also expressed in part of the anterior compartment of the adult mesothorax (notum). We report experiments concerning the role of these genes in the notum. In the absence of eyg function the anterior-central region does not develop, whereas ectopic activity of either eyg or toe induces the formation of the anterior-central pattern in the posterior or lateral region of the notum. These results demonstrate that eyg and toe play a role in the genetic subdivision of the notum, although the experiments indicate that eyg exerts the principal function. However, by itself the Eyg product cannot induce the formation of notum patterns; its thoracic function requires co-expression with the Iroquois (Iro) genes. We show that the restriction of eyg activity to the anterior-central region of the wing disc is achieved by the antagonistic regulatory activities of the Iro and pnr genes, which promote eyg expression, and those of the Hh and Dpp pathways, which act as repressors. We argue that eyg is a subordinate gene of the Iro genes, and that pnr mediates their thoracic patterning function. The activity of eyg gives rise to a new notum subdivision that acts upon the pre-extant one generated by the Iro genes and pnr. As a result the notum becomes subdivided into four distinct genetic domains.
In Drosophila, the morphological diversity is generated by the activation of different sets of active developmental regulatory genes in the different body subdomains. Here, we have investigated the role of the homothorax/extradenticle (hth/exd) gene pair in the elaboration of the pattern of the anterior mesothorax (notum). These two genes are active in the same regions and behave as a single functional unit. We find that their original uniform expression in the notum is downregulated during development and becomes restricted to two distinct, alpha and betasubdomains. This modulation appears to be important for the formation of distinct patterns in the two subdomains. The regulation of hth/exd expression is achieved by the combined repressing functions of the Pax gene eyegone (eyg) and of the Dpp pathway. hth/exd is repressed in the body regions where eyg is active and that also contain high levels of Dpp activity. We also present evidence for a molecular interaction between the Hth and the Eyg proteins that may be important for the patterning of the alpha subdomain.
A study of shaggy mutant clones on the notum reveals that a greater number of cells are diverted into the bristle pathway of differentiation and fewer cells remain to produce the epidermis, shaggy clones differentiate supernumerary microchaetae and macrochaetae but these are found in the correct spatial locations, e.g. clusters of macrochaetae are formed round the position of the extant macrochaetae. The shaggy mutant phenotype requires the functioning of the genes of the achaete-scute (AS-C) complex but a dosage study shows that it is unlikely that the AS-C is overexpressed in shaggy cells. Data are presented that argue, also, for a correct spatial expression of the AS-C in shaggy mutants. A study of clones doubly mutant for shaggy and different achaete and scute alleles is consistent with the hypothesis that the clusters of macrochaetae formed by shaggy represent the restricted spatial domains of expression of the AS-C. The results can be reconciled with the known role for the AS-C, in determining which bristle types differentiate where, and a role for shaggy in the cell interactions, within domains of the AS-C expression, leading to the definition of only one bristle mother cell.
In Drosophila the stereotyped arrangement of sensory bristles on the notum is determined by the tightly regulated control of transcription of the achaete-scute (ac-sc) genes which are expressed in small proneural clusters of cells at the sites of each future bristle. Expression relies on a series of discrete cis-regulatory elements present in the ac-sc gene complex that are the target of the transcriptional activators pannier (pnr) and the genes of the iroquois complex. Stereotyped bristle patterns are common among species of acalyptrate Schizophora such as Drosophila, and are thought to have derived from an ancestral pattern of four longitudinal rows extending the length of the scutum, through secondary loss of bristles. To investigate evolutionary changes in bristle patterns and ac-sc regulation by pnr, we have isolated homologues of these genes from Calliphora vicina, a species of calyptrate Schizophora separated from Drosophila by at least 100 million years. Calliphora vicina displays a pattern of four rows of bristles on the scutum resembling the postulated ancestral one. We find that sc in Calliphora is expressed in two longitudinal stripes on the medial scutum that prefigure the development of the rows of acrostichal and dorsocentral bristles. This result suggests that a stripe-like expression pattern of sc may be an ancestral feature and may have preceded the evolution of proneural clusters. The implications for the evolution of the cis-regulatory elements responsible for sc expression in the proneural clusters of Drosophila, and function of Pnr are discussed.
The innervation pattern of inhibitory motor neurones of the locust has been revealed by intracellular recording from their cell bodies in the meso- and metathoracic ganglion and simultaneous recording from muscle fibres in a middle, or in a hind leg. Three neurones in each ganglion, the common inhibitor (CI = CI1), the anterior inhibitor (AI = CI2), and the posterior inhibitor (PI = CI3) innervate several muscles in one leg and are thus common inhibitory neurones. Metathoracic CI innervates 13 muscles in one hind leg and mesothoracic CI innervates 12 muscles in one middle leg. The muscles are all in the proximal parts of the legs and move the coxa, the trochanter and the tibia. Metathoracic AI and PI innervate four muscles in the more distal parts of one hind leg that move the tibia, the tarsus and the unguis. None of these muscles is innervated by CI. Each inhibitor innervates muscles that have different and often antagonistic actions during movements of a leg. AI and PI receive many synaptic inputs in common and show similar patterns of spikes during imposed movements of a tibia. Tests fail, however, to reveal evidence for any electrical or synaptic coupling between them. A revised scheme of nomenclature for these inhibitory neurones is proposed.