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Biomedical subjects

M Demedts

Publications and source records attributed to M Demedts.

At least 199 records · Page 11Linked to original sources
PubMed1985

Human esophageal pressures and chest wall configuration in upright and head-down posture.

Pressures were measured at two levels in the esophagus in 14 young healthy subjects performing slow inspiratory and expiratory vital capacity (VC) maneuvers in upright and head-down posture (180 degrees body tilt). In both postures, a gravitational pressure gradient was found, which increased very slightly with decreasing lung volumes (0.006 cmH2O X % VC-1 X cm descent-1) except for upright expiratory curves above 60% VC. The expiratory pressure gradient tended to be larger in head-down than in upright posture; however, during inspiration the opposite was true. In both postures the pressure change between 100 and 20% VC was smaller in the uppermost zone, which is consistent with the smaller changes in alveolar expansion in this zone. Also, in seven of the subjects, changes in cross-sectional area of the middle and lower part of the rib cage (HRC and LRC) and of the abdomen (ABD) were measured by respiratory inductive plethysmography in upright and head-down posture. The ratio of HRC motion to LRC motion was constant throughout the VC and did not change with posture, yet the ratio of ABD motion to mean RC motion changed with overall volume and was also larger in head-down than in upright posture. In conclusion, the changes in esophageal pressure gradient during slow VC maneuvers in head-down vs. upright posture were not related to (and thus not caused by) changes in chest wall configuration.

Adult↗
PubMed1985

The inherited association of interstitial lung disease, hypocalciuric hypercalcemia, and defective granulocyte function.

The history and pulmonary histopathology of 3 siblings, presenting with the association of idiopathic interstitial lung disease, hypocalciuric hypercalcemia, and an intrinsic defect in granulocyte function are described. Prospective examination of 40 family members indicated that the 3 abnormalities are inherited according to an autosomal dominant pattern with, however, a variable penetration. Lung biopsies in the index cases revealed an interstitial infiltration of inflammatory cells and aggregates of conchoid bodies surrounded by multinucleated giant cells. Bronchoalveolar lavage was performed in 11 subjects and often showed an elevated cell recovery and abnormal cell distribution indicative of active alveolitis. In several subjects, multinucleated giant cells were found. The diffusing capacity (in percent predicted) showed a significant decrease with age, independent of smoking habits. The hypocalciuric hypercalcemia was unaffected by steroids or parathyroidectomy. It was not associated with abnormal levels of parathyroid hormone, calcitonin, 25-hydroxy-vitamin D3, 1,25-dihydroxy-vitamin D3, or angiotensin-converting enzyme.

Adult↗
PubMed1985

Cobalt-induced bronchial asthma in diamond polishers.

Three diamond workers had occupational asthma attributed to the inhalation of cobalt powder. The exposure originated from high speed polishing disks with an abrasive consisting of microdiamonds cemented in extra fine cobalt not alloyed to tungsten carbide. The bronchoconstriction progressed towards the end of working-days; it was especially pronounced in the absence of an adequate exhaust ventilation; and it could be accompanied by rhinitis and chest tightness. Cobalt inhalation challenge tests were positive in all three patients, and exposure to cobalt temporarily increased nonspecific hyperreactivity.

Adult↗
PubMed1985

Defective host defence mechanisms in a family with hypocalciuric hypercalcaemia and coexisting interstitial lung disease.

An extensive in vitro investigation of the host defence system was performed in 11 sibs of a large kindred with unexplained combination of familial hypocalciuric hypercalcaemia (FHH), interstitial lung disease and increased susceptibility to respiratory infections. The impairment of host defence mechanism was most likely related to granulocyte dysfunction. A severe myeloperoxidase deficiency was the most consistent granulocyte defect (P less than 0.001) and it was associated with a relatively diminished chemiluminescence (P less than 0.001). Moreover, a significantly diminished antistaphylococcal phagocytic (P less than 0.001) and killing (P less than 0.001) activity was found which in the absence of any opsonizing defect implicates an intrinsic granulocyte dysfunction. We found no abnormalities in number of B and T lymphocytes nor in the balance between helper and suppressor cells determined with monoclonal antibodies. Despite the recurrent infections no elevations of the immunoglobulin subclasses were found. The relationship between the inherited FHH, interstitial lung disease and susceptibility to respiratory infections remains obscure. It is, however, clear that impairment of the host defence might contribute to a decreased life expectancy in this family.

Adult↗
PubMed1984

Cobalt lung in diamond polishers.

Five diamond polishers with interstitial lung disease attributed to cobalt not alloyed to carbides of hard metals are described. The exposure originated from high-speed grinding tools with a polishing surface of microdiamonds cemented in very fine cobalt. Mineralogic analysis of lung tissue, lavage fluid, filtered air, and exhaust dust in the work environment revealed cobalt as the only toxic agent. Complaints consisted of work-related rhinitis, cough, chest tightness, dyspnea, anorexia, and weight loss, and were intensified in the absence of an adequate exhaust ventilation. Three subjects were in a rather subacute stage, as documented by open lung biopsy in 2 of them, and had a severe restrictive defect and markedly decreased diffusing capacity. Two patients presented a more chronic histologic pattern and had a less decreased diffusing capacity. Open lung biopsies showed in these 4 a fibrosing alveolitis, mainly of the centrilobular zones. In the former 2 patients, subacute lesions consisting of a mural mononuclear cell infiltrate, marked intra-alveolar desquamation, and multinucleated giant cells were found, whereas in the latter 2, centrilobular fibrosis with some microcyst formation was also already seen. Multiple multinucleated giant cells were present in the bronchoalveolar lavage fluid. Interruption of the exposure, with or without corticotherapy, caused a rapid regression of the complaints and a partial improvement of lung function.

Adolescent↗
PubMed1984

Spontaneous regression of lung metastases of adenoid cystic carcinoma.

Two patients with spontaneous regression of histologically confirmed lung metastases from a classic cribriform adenoid cystic carcinoma are presented. The first case was moribund when multiple small lung metastases were detected, but after a very strict diet, he presented progressive improvement in his general condition and regression of the metastases. In the second case, three large lung metastases and a subcutaneous metastasis regressed after several local recurrences of the primary tumor had been removed.

Adult↗
PubMed1984

Altered parathyroid set point to calcium in familial hypocalciuric hypercalcaemia.

Changes in calcium concentration were induced by an infusion of disodium-EDTA or calcium in 2 members of a family suffering from hypocalciuric hypercalcaemia ( FHH ) associated with interstitial lung disease. These changes in calcium demonstrated an inverse linear relationship with the changes in serum parathyroid hormone (PTH). Infusion of EDTA in control subjects and in patients with an adenoma or hyperplasia of the parathyroid glands also showed inverse relationships between calcium and PTH. The correlation between serum calcium and serum PTH was significant over the range observed during the induced hypo- and/or hypercalcaemia in controls and in patients with FHH or adenoma. The regressions were, however, shifted relative to each other: in comparison with controls, the FHH was displaced upwards and to the right, although not as far as the adenomas. These findings suggest the existence of an elevated set point for extracellular calcium (or calciostat ) in FHH .

Adenoma↗
PubMed1984

Alveolar T-cell subsets in pulmonary sarcoidosis. Correlation with disease activity and effect of steroid treatment.

Alveolar lymphocytes, obtained by bronchoalveolar lavage in 35 patients with sarcoidosis, were analyzed with monoclonal antibodies to lymphocyte subsets. Untreated patients had significantly higher percentages of Leu 3a (+) T helper-inducer cells (THI) and significantly lower Leu 2a (+) T cytotoxic-suppressor cells (TCS) within the alveolar lymphocyte population than did normal control subjects (p less than 0.002). The mean ratio of alveolar THI to TCS cells was 6.20 +/- 3.76 versus 1.44 +/- 0.54 in control subjects (p less than 0.002). Untreated patients had a percentual enrichment of THI cells among alveolar lymphocytes relative to blood (p less than 0.0002), whereas TCS cells in percent of lymphocytes were lower in alveolar lavage fluid than in blood (p less than 0.002). These shifts were not observed in the control subjects. Patients with high-intensity alveolitis (i.e., T cells constituted 28% or more of alveolar inflammatory cells) had significantly greater proportions of THI cells among alveolar lymphocytes than did those with low-intensity alveolitis (p less than 0.01). This percent of alveolar THI cells correlated positively with the number of lymphocytes and T cells in percent of alveolar cells (p less than 0.03), which both are indexes of disease activity. In untreated patients who were lavaged at least twice, a decrease in the THI/TCS ratio was found to accompany or precede radiologic and clinical improvement, but the initial THI/TCS ratio was not predictive of further evolution. Steroid treatment decreased the THI/TCS ratio with a marked increase in the proportion of TCS cells. These changes were independent of an effect on the number of alveolar lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Bronchoalveolar lavage in eosinophilic pneumonia before and during corticosteroid therapy.

In 5 untreated patients with eosinophilic pneumonia of unknown origin, bronchoalveolar lavage (BAL) fluid was characterized by a markedly increased number of eosinophils (mean +/- 1 SD:42 +/- 22% of effector cells), which reverted to normal during treatment with corticosteroids. These findings indicate that besides the classic patterns of increased lymphocytosis or polymorphonuclear leukocytosis, a predominantly eosinophilic pattern also may be present in the BAL fluid.

Adrenal Cortex Hormones↗
PubMed1984

Transdiaphragmatic, esophageal and gastric pressures during maximal static inspiratory and expiratory efforts in young subjects: effects of maneuver and sex.

Esophageal (Pes), gastric (Pga) and transdiaphragmatic (Pdi) pressures were measured in 6 young healthy men and 6 women during maximal static inspiratory and expiratory efforts. Interindividual variations were large for all pressures, but the measurements were highly reproducible within each subject. During maximal inspiratory efforts without instruction as to the type of breathing, Pga was often around zero whereas during standardized maximal inspiratory efforts (i.e. with protruded abdomen), Pdi and Pga increased significantly and Pes tended to be less negative. Thus, maximal strength of the diaphragm is only measured during standardized efforts. During maximal expiratory efforts Pes and Pga tended to be larger during spontaneous than during standardized maneuvers (i.e. with retracted abdomen), and to increase with lung volume. The clinical information obtained from Pdi, Pes and Pga during maximal inspiratory and expiratory efforts is probably not more specific than that from transrespiratory pressures (i.e. measurements at the mouth), except for standardized inspiratory efforts which may allow differentiation of intercostal-accessory and diaphragm-abdominal dysfunction.

Abdomen↗
PubMed1983

Regional gas distributions and single-breath washout curves in head-down position.

Regional distributions of inspired 133Xe and single-breath washout curves were compared in six young healthy subjects for the upright and the head-down positions. The regional distributions of volumes (at 0, 25, 50, and 75% vital capacity, VC) and of 133Xe boluses inhaled at residual volume (RV) were inverted in the head-down position, thus behaving as if they were determined by gravity acting via the weight of the lung rather than by thoracicoabdominal shape adaptations. Nevertheless no mirror image was obtained. The vertical differences in regional distribution of the 133Xe RV bolus and of the volumes at 25% VC were increased in the head-down position, whereas the vertical difference in volumes at RV was decreased, indicating enhanced air trapping and sequential ventilation at low volumes. This was attributed to the effect of the increased pulmonary blood volume in the head-down posture. Accordingly the size of phase IV on the washout curves with the SF6-bolus as well as with the N2-resident gas method was increased in the head-down position.

Adult↗
PubMed1983

Gravity dependence of phases III, IV, and V in single-breath washout curves.

The gravity dependence of phases III (IIIa and IIIb), IV, and V of simultaneously performed He-bolus and N2-resident gas single-breath washout curves was studied in different body positions by the technique of 180 degrees body inversion between inspiration and expiration. Phase IIIa was mainly determined by nongravitational factors. Phase IIIb was influenced by gravitational, as well as nongravitational, factors. The former were more important with the bolus method in both lateral decubitus positions and the latter with the N2 method in the prone and supine positions. Phases IV and V were mainly gravity dependent. The difference in gravity dependence between the He and N2 methods appeared to be correlated with the vertical interregional concentration gradients of both gases; indeed the vertical gradient was larger for the 133Xe bolus inhaled at residual volume (which is comparable to the He-bolus distribution) than for the 133Xe residual volume-to-total lung capacity ratio (which is comparable to the N2-resident gas distribution). The greater gravity dependence in the lateral decubitus positions than in the supine or prone postures was related to the larger vertical interregional concentration difference as well as to the more pronounced sequential ventilation in the former positions. Finally the negligible effect of gravity on phase IIIa, its moderate effect on phase IIIb, and its predominant effect on phases IV and V were in agreement with the increased sequential filling and emptying due to gravity near residual volume.

Adult↗