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Biomedical subjects

M Demedts

Publications and source records attributed to M Demedts.

At least 181 records · Page 10Linked to original sources
PubMed1987

D-penicillamine therapy and interstitial lung disease in scleroderma. A long-term followup study.

Sequential lung function tests were performed on 17 scleroderma patients who were treated with D-penicillamine (DP) (total of 66 treatment years) and on 10 control scleroderma patients who were not treated or were treated with low-dose prednisone (total of 25 treatment years). Cusum plots showed significant differences between the 2 groups in their cumulative changes in carbon monoxide diffusing capacity (DLCO) (P less than 0.005) and in DLCO/lung volume (P less than 0.02). The end value of the DLCO was greater than 10% lower than the initial value in 3 of the 17 DP-treated patients versus 5 of the 10 control patients (P less than 0.01, Fisher's exact probability test); in 3 DP-treated patients and 8 control patients (P less than 0.003, Fisher's exact probability test), the end value of the DLCO/lung volume was greater than 10% lower than the initial value. We conclude that DP has a beneficial effect on interstitial lung disease in patients with scleroderma.

Carbon Monoxide↗
PubMed1987

Adult linear IgA bullous dermatosis with bronchial involvement.

A 54-year-old man is described, suffering from adult linear IgA bullous dermatosis with involvement of the bronchial mucosa. The main respiratory symptoms were recurring haemoptysis, episodic narrowing of the airways and persistent non-specific bronchial hyperreactivity. On CT scan the trachea had a saber-sheath shape with tracheal ring calcification. Endoscopically the tracheo-bronchial mucosa was diffusely purpuric and hyperaemic and also showed pale elevated plaques, bullous lesions and ulceration. Histological examination of biopsies of skin and nasal and tracheo-bronchial mucosa showed subepithelial blister formation associated with an accumulation of polymorphonuclear cells at the epithelial-subepithelial junction, and linear IgA deposits on direct immunofluorescence.

Bronchi↗
PubMed1987

Effects of acute hyperinflation on chest wall mechanics in dogs.

We studied chest wall mechanics at functional residual capacity (FRC) and near total lung capacity (TLC) in 14 supine anesthetized and vagotomized dogs. During breathing near TLC compared with FRC, tidal volume decreased (674 +/- 542 vs. 68 +/- 83 ml; P less than 0.025). Both inspiratory changes in gastric pressure (4.5 +/- 2.5 vs. -0.2 +/- 2.0 cmH2O; P less than 0.005) and changes in abdominal cross-sectional area (25 +/- 17 vs. -1.0 +/- 4.2%; P less than 0.001) markedly decreased; they were both often negative during inspiration near TLC. Parasternal intercostal shortening decreased (-3.0 +/- 3.7 vs. -2.0 +/- 2.7%), whereas diaphragmatic shortening decreased slightly more in both costal and crural parts (costal -8.4 +/- 2.9 vs. -4.3 +/- 4.1%, crural -22.8 +/- 13.2 vs. -10.0 +/- 7.5%; P less than 0.05). As a result, the ratio of parasternal to diaphragm shortening increased near TLC (0.176 +/- 0.135 vs. 0.396 +/- 0.340; P less than 0.05). Electromyographic (EMG) activity in the parasternals slightly decreased near TLC, whereas the EMG activity in the costal and crural parts of the diaphragm slightly increased. We conclude that 1) the mechanical outcome of diaphragmatic contraction near TLC is markedly reduced, and 2) the mechanical outcome of parasternal intercostal contraction near TLC is clearly less affected.

Abdomen↗
PubMed1987

Once-daily dosing of a new ultrasustained-release theophylline preparation.

Theophylline plasma levels and profiles were evaluated in patients with chronic obstructive pulmonary disease during once-daily dosing of an ultrasustained-release theophylline preparation (Theo-1; capsules filled with microgranules containing 400 mg anhydrous theophylline). In a first study, 6 patients received a single morning dose of 800 mg (a) in the fasting state, and (b) with a protein-fat-rich breakfast in a random order, and the systemic theophylline availability was evaluated for 48 h. No significant differences were found either in Cmax (a: 7.0 +/- 3.2 micrograms/ml; b: 7.6 +/- 2.6 micrograms/ml), or in Tmax (a: 11.7 +/- 6.1 h; b: 10.2 +/- 3.6 h). Elimination half-life was in a 11.4 +/- 4.4 h and in b 12.9 +/- 4.8 h (p less than 0.05). In a second study, the steady-state theophylline levels were measured during a 24-hour dosage interval on day 8 after intake of 800 mg at 8 a.m. in 16 patients and at 8 p.m. in 11 patients. Plateau-shaped plasma concentration-time curves were obtained, with small fluctuations between the peak (Cmax) and trough (Cmin) levels: [100(Cmax-Cmin)/Cmin] was 83 +/- 40% after morning dose, and 54 +/- 26% after evening dose (p less than 0.05). Cmax was 12 +/- 5 and 11 +/- 4 micrograms/ml, respectively (NS). Tmax was 9 +/- 3 and 11 +/- 3 h, respectively (NS). The FDA fluctuation for the 37 patients was 48 +/- 20%. In a third study, the dose-plasma concentration relationship was evaluated in steady state in 6 patients receiving 400, 800 and 1,200 mg for 3 days each. The trough plasma concentrations were 2.6 +/- 0.9, 6.2 +/- 2.1 and 10.2 +/- 3.1 micrograms/ml, respectively. Six hours after drug intake the plasma levels were 5.0 +/- 1.6, 10.6 +/- 2.5 and 15.4 +/- 4.2 micrograms/ml, respectively; and 12 h after drug intake, 4.9 +/- 1.4, 11.6 +/- 2.4 and 14.5 +/- 3.7 micrograms/ml, respectively. In conclusion, we found in these studies that with once-daily dosing of the ultrasustained-release preparation Theo-1, plateau-shaped 24-hour theophylline plasma levels could be achieved. The relationship between daily dosage and theophylline plasma levels was linear intraindividually but showed an important interindividual variation. No consistent interference by food intake was found and no serious side effects occurred within therapeutic plasma levels.

Aged↗
PubMed1987

Total respiratory resistance and reactance in patients with upper airway obstruction.

In 18 patients with upper airway obstruction, we measured dynamic lung volumes, maximal flows, airway resistance (Raw), and total respiratory resistance (Rrs) and reactance (Xrs) at various frequencies by means of a forced oscillation method. Patients were classified according to the site and the type of the obstruction. The values of Raw, Rrs and Xrs were tightly correlated and reflected the overall importance of the obstruction. In comparison with patients with chronic obstructive pulmonary disease the values of Rrs tend to be higher and to be influenced more by support of the cheeks during the measurement. These differences are not diagnostic, however.

Airway Resistance↗
PubMed1987

Hypocapnic hyperventilation versus isocapnic hyperventilation with ambient air or with dry air in asthmatics.

The effects of three types of hyperventilation challenge tests (free hypocapnic, ambient air; controlled isocapnic, ambient air; controlled isocapnic, dry air), on FEV1 and on Raw were compared in 12 asymptomatic asthmatics. Controlled isocapnic hyperventilation of dry air as well as of ambient air caused bronchoconstriction lasting for more than 8 min, but the degree of bronchoconstriction was significantly greater with the former. Free hypocapnic hyperventilation of ambient air caused peak bronchoconstriction after 1 min, followed by a steady functional improvement; the values after 1 min were similar to those following isocapnic dry air hyperventilation, and values after 8 and 15 min were similar to those following isocapnic ambient air hyperventilation. The changes in Raw induced by the three types of hyperventilation were not influenced by a preceding full inspiration. In the eight subjects in whom the lung function had returned to within 10% of control after 30 min, identical duplicate hyperventilation challenge tests performed at that time demonstrated a significant, partial refractoriness for all tests. Thus the simple, free hypocapnic, hyperventilation test with ambient air was found to be as reliable as the more sophisticated controlled isocapnic tests.

Adult↗
PubMed1987

Combined asthma and alveolitis induced by cobalt in a diamond polisher.

A diamond polisher presented with a history of dyspnea, chest tightness, chills and weight loss related to exposure to diamond cobalt disks at work. Pulmonary function showed slightly reduced lung volumes, low normal diffusing capacity and a moderate bronchial hyperresponsiveness to histamine. Chest X-ray and cell count in bronchoalveolar lavage fluid were normal. After 3 months of non-exposure, a bronchial cobalt challenge test caused an immediate decrease in specific airway conductance and in vital capacity (VC) but not in FEV1/VC. After 6 h, chills, fever, tachycardia and crackles appeared along with moderate reductions in lung volumes. After 24 h, the bronchoalveolar lavage fluid showed 43% granulocytes, and there was a marked increase in bronchial hyperresponsiveness to histamine. These changes are interpreted as combined asthma and alveolitis induced by cobalt.

Alveolitis, Extrinsic Allergic↗
PubMed1986

Scintigraphic evaluation of shape of lung and chest in upright and head-down posture.

We determined the configuration of lungs and chest in six healthy young subjects using anteroposterior and lateral technetium-99m-labeled scintigraphic images obtained in upright and in 90 degree head-down posture at 0, 25, 50, 75, and 100% vital capacity (VC). The lung shape was evaluated from curves relating vertical height vs. cumulative volume of 20 apicodiaphragmatic lung zones of equal height. S-shaped curves were obtained, which, after size normalization, were largely independent of volume or posture (P greater than 0.1). However, the apical zones tended to become relatively wider and the diaphragmatic zones relatively smaller with increasing volume, especially between 0 and 25% VC in upright posture and 0-50% VC in head-down posture. Changing posture from upright to head-down also tended to slightly widen the apical zones and to narrow the diaphragmatic zones, which is in line with a greater intrathoracic penetration of the diaphragm/abdomen. The shape of the chest was evaluated from the ratio of the transverse-thoracic and anteroposterior distances over height. These ratios did not clearly change with posture (P greater than or equal to 0.05) but increased by approximately 30% with decreasing volume (P less than 0.01). The fact that these shape changes of the chest were not accompanied by similar changes in lung shape can be explained mainly by widening of the mediastinum when volume decreases. In conclusion, the shape of the lung and chest are similar in head-down and upright humans, in contrast to the reversal of the apicodiaphragmatic differences in alveolar expansion and in transpulmonary pressure.

Adult↗
PubMed1986

Effect of rib cage and abdominal restriction on total respiratory resistance and reactance.

In 14 healthy male subjects we studied the effects of rib cage and abdominal strapping on lung volumes, airway resistance (Raw), and total respiratory resistance (Rrs) and reactance (Xrs). Rib cage, as well as abdominal, strapping caused a significant decrease in vital capacity (respectively, -36 and -34%), total lung capacity (TLC) (-31 and -27%), functional residual capacity (FRC) (-28 and -28%), and expiratory reserve volume (-40 and -48%) and an increase in specific airway conductance (+24 and +30%) and in maximal expiratory flow at 50% of control TLC (+47 and +42%). The decrease of residual volume (RV) was significant (-12%) with rib cage strapping only. Abdominal strapping resulted in a minor overall increase in Rrs, whereas rib cage strapping produced a more marked increase at low frequencies; thus a frequency dependence of Rrs was induced. A similar pattern, but with lower absolute values, of Rrs was obtained by thoracic strapping when the subject was breathing at control FRC. Xrs was decreased, especially at low frequencies, with abdominal strapping and even more with thoracic strapping; thus the resonant frequency of the respiratory system was shifted toward higher frequencies. Partitioning Rrs and Xrs into resistance and reactance of lungs and chest wall demonstrated that the different effects of chest wall and abdominal strapping on Rrs and Xrs reflect changes mainly of chest wall mechanics.

Abdomen↗
PubMed1986

Relationship between diaphragm length and abdominal dimensions.

We examined the relationship between changes in abdominal cross-sectional area, measured by respiratory inductive plethysmography, and changes in length in the costal and crural parts of the diaphragm, measured by sonomicrometry, in nine supine, anesthetized dogs. During passive inflation, both parts of the diaphragm shortened and abdominal cross-sectional area increased. During passive deflation, both parts of the diaphragm lengthened and abdominal cross-sectional area decreased. We subsequently used the relationship between costal and crural diaphragmatic length, respectively, and abdominal cross-sectional area during passive inflation-deflation to predict the length changes in the costal and crural diaphragm during quiet breathing before and after bilateral phrenicotomy. In the intact animal the inspiratory shortening in the crural diaphragm was almost invariably greater than predicted from the relationship during passive inflation. During inspiration after phrenicotomy the crural diaphragm invariably lengthened, whereas the costal diaphragm often shortened. In general there was a good correlation between the measured and predicted length change for the crural diaphragm (r = 0.72 before and 0.79 after phrenicotomy) and a poor one for the costal diaphragm (r = 0.05 before and 0.19 after phrenicotomy).

Abdomen↗
PubMed1986

Influence of common cold and of parenteral administration of influenza virus antigens on bronchoalveolar lavage cells.

We investigated in a pilot study on healthy young subjects whether a common cold or a vaccination with influenza virus antigens within 10 days influenced the number and subsets of inflammatory cells in the bronchoalveolar lavage (BAL) fluid. The total number of BAL-cells was about doubled in the common cold group, yet no consistent changes in overall cell distribution was found. Among BAL-lymphocytes the ratio of helper-inducer over suppressor-cytotoxic lymphocytes (THI/TCS) tended to be increased in both groups, due to a lower percentage of TCS-cells, which was significant in the vaccination group only. In the blood, on the contrary, the THI/TCS ratio was significantly decreased in both groups due to a drop in THI-cells; in addition, the proportions of E-Rosette (+) T-cells and of activated (Ia+) T-cells were slightly increased. In conclusion, only minor changes in inflammatory BAL-cells were observed, which, however, may interfere with the effects of other diseases.

Adult↗
PubMed1986

Rounded atelectasis of the lung: diagnosis on conventional radiology and CT.

Rounded atelectasis is a radiological diagnosis and has to be differentiated from other mass-like opacities in the dorso (basal) part of the chest. Differential diagnosis must first be made with malignant pleural and pulmonary tumors. Specific radiological features such as irregular pleural thickening and the "comet-tail" sign help to make the diagnosis and to avoid unnecessary surgery. CT may be very helpful but frontal or sagittal conventional tomography will often be more diagnostic.

Female↗
PubMed1985

Coexistence of hypocalciuric hypercalcaemia and interstitial lung disease in a family: a cross-sectional study.

In a prospective investigation, a large kindred (twenty-one subjects) with unexplained association of familial hypocalciuric hypercalcaemia and idiopathic interstitial lung disease was studied. Serum calcium was increased in fifteen patients (the youngest being 7 years old) and was associated with hypo- or normocalciuria. The abnormalities were not age-dependent. The serum concentrations of parathyroid hormone, 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3 and calcitonin were normal. In twelve patients the diffusing capacity (DLCO) and/or DLCO per unit lung volume was less than 75% predicted. This was often accompanied by a vital capacity of less than 80% predicted, and increased Tiffeneau index, and a reticulo-micronodular pattern with high diaphragm on chest X-ray. The decrease in DLCO was more pronounced in older non-smoking as well as smoking subjects (P less than 0.02) suggesting a progressing interstitial disease with age. The fibrosing alveolitis, which had been confirmed by open lung biopsy in three subjects, could not be attributed to sarcoidosis, collagen-vascular disease, or exogenous causes. The disturbances in the calcium homeostasis and in the diffusing capacity of the lung coexisted in seven of the twenty-one patients. Apparently, both abnormalities were inherited following an autosomal-dominant pattern but with a different penetration in each person, and seemed not be causally related to each other.

Adolescent↗