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Biomedical subjects

M Demedts

Publications and source records attributed to M Demedts.

At least 109 records · Page 6Linked to original sources
PubMed1994

Transcarinal needle aspiration biopsy in the staging of lung cancer.

Lung cancer without distant metastasis often requires an invasive surgical procedure to document inoperability. In order to determine how often puncture biopsy was a valid substitute for a surgical procedure, we investigated the performance of endoscopic staging by means of transcarinal needle aspiration biopsy during rigid bronchoscopy. Eighty lung cancer patients with subcarinal lymph nodes visible on computed tomography (CT) scan were studied. Specimens were of histological quality (i.e. lymph node tissue) in 59 out of 80 (74%) patients, and showed malignant invasion of this lymph node tissue in 43 cases. Specimens of cytological quality (i.e. lymph node cells) were obtained in 13 out of 80 (16%) patients, and showed malignancy in 7 cases. Therefore, adequate evaluation of the subcarinal lymph nodes was possible in 72 out of 80 (90%) patients. In 50 of these 72, malignant mediastinal spread was proven, and further invasive surgical staging could be avoided. Subgroup analysis showed that this outcome tended to be more likely in patients with abnormal endoscopic appearance of the main carina, with locally extensive tumours, and with nonsquamous histology. These results indicate that transbronchial needle aspiration biopsy of subcarinal lymph nodes can be a valuable alternative to more invasive surgical staging in patients selected by CT scan.

Adult↗
PubMed1994

Completely reversible respiratory insufficiency with persisting ultrastructural ciliary abnormalities.

A male nonsmoker, born in 1946, suffered from hypersecretory bronchitis and recurrent upper and lower respiratory tract infections since adolescence. In 1983 he developed pulmonary insufficiency. In 1984, some months after daily occupational exposure to printing inks and glues, forced expiratory volume in one second (FEV1) was 1.1 l (28% pred) and arterial oxygen tension (PaO2) 44 mmHg (5.9 kPa). Open lung biopsy showed a centri-acinar bronchiolitis-alveolitis suggestive of an airborne toxic pathology. Ultrastructural examination of the bronchial mucosa revealed microtubular abnormalities in about 10% of the cilia. Treatment consisted of stopping work from December 1985, oral corticosteroids until 1988, bronchodilators on a regular basis and intermittent antibiotics (1 week/month). The evolution was remarkable because: 1) from a severe pulmonary insufficiency, refractory to bronchodilators and corticosteroids for several years, lung function slowly improved to supernormal values, without residual functional signs of small airways disease; and 2) a repeat ultrastructural nasal mucosa examination in 1992 still showed persisting microtubular abnormalities in about 10% of the cilia, which disappeared on sequential monolayer-suspension culture, thus indicating secondary ciliary abnormalities.

Bronchi↗
PubMed1994

Lung function, CT-scan and X-ray in upper airway obstruction due to thyroid goitre.

The purpose of this study was to assess the clinical reliability and to compare routine lung function tests (maximal flows and resistance) and radiological images (computed tomography (CT)-scan and X-ray) in upper airway obstruction. We, therefore, performed these examinations prospectively in 28 female patients (aged 68 +/- 13 yrs) with a goitre and without pulmonary disorders. Lung function measurements consisted of maximum expiratory and inspiratory flow-volume curves and of airway resistance. CT-scans and X-rays were performed during apnoea at functional residual capacity (FRC). Peak expiratory flow was 3.6 +/- 1.3 l.s-1 (i.e. 62 +/- 21% predicted); airway resistance was 0.38 +/- 0.14 kPa (i.e. 149 +/- 58% pred); and specific conductance was 1.0 +/- 0.3 kPa (i.e. 70 +/- 24% pred). Almost all lung function tests were significantly correlated with each other. On CT-scan the tracheal cross-sectional area at the zone of tracheal narrowing could be evaluated in 26 patients and was 58 +/- 17% (CT1/2) of the control area 2 cm above the carina (CT2). On X-ray the sagittal and coronal tracheal diameters at the zone of narrowing could only be measured in 16 subjects and were 60 +/- 17% (X-dia1/2) of the diameter at the control level. CT1/2 and X-dia1/2 were significantly correlated to each other. No correlation was found between the lung function tests and the radiological indices except airway resistance and CT2. Routine lung function and CT-scan do not provide comparable information on the degree of airway obstruction due to a goitre.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Acute pulmonary oedema in patients with primary pulmonary hypertension and normal pulmonary capillary wedge pressure.

Acute pulmonary oedema with normal pulmonary capillary wedge pressure, occurred in 2 patients with primary pulmonary hypertension, probably due to venoocclusive diseases. In both cases an increase in cardiac output induced by vasodilator therapy with a calcium antagonist or a viral infection with fever lead to an increase in hydrostatic pulmonary capillary pressure which was not identical to the pulmonary capillary wedge pressure.

Acute Disease↗
PubMed1993

Bleeding varices due to portal hypertension in sarcoidosis. Favorable effect of propranolol and prednisone.

A 58-year-old white man had bleeding varices in the gastric fundus due to portal hypertension attributable to histologically proven hepatic sarcoid involvement with a giant splenomegaly and with an angiographically demonstrated significant flow toward the liver. Treatment with corticosteroids and beta-blockade (30 mg propranolol daily) resulted in no rebleeding for over one year follow-up.

Drug Therapy, Combination↗
PubMed1993

Differences in CT density between dependent and nondependent portions of the lung: influence of lung volume.

OBJECTIVE: Lung tissue, blood, and air determine the physical density of the lung and hence the attenuation measured on CT scans. These components are not homogeneously distributed throughout the lungs, and their relative proportion changes continuously during respiration. The objective of this study was to measure densities in various areas of the normal lung with CT and to examine the influences of gravity and of the degree of lung inflation on these densities. SUBJECTS AND METHODS: The subjects in the study were six healthy male volunteers. CT scans were obtained at the level of the aortic arch and 2 cm above the expiratory level of the diaphragm with the subjects supine and then with them prone. Scans were obtained at lung volumes of 10%, 50%, and 90% vital capacity by using a respiratory gating device connected to the CT scanner. The overall density of the lungs at these two levels and the densities in the dependent (posterior in supine, and anterior in prone body position) and nondependent (anterior in supine and posterior in prone body position) areas were measured by using a semiautomatic evaluation algorithm. RESULTS: Changes in lung volume caused the same changes in lung density in the right and left lungs and in the upper and lower parts of the lungs. For both body positions (supine and prone), the difference between lung density at 10% vital capacity and that at 90% vital capacity was significantly larger (p < .05) in the dependent parts of the lung than in the nondependent parts. In both positions, differences in density between dependent and nondependent regions were significantly (p < .05) greater at 10% vital capacity than at 90% vital capacity, and the differences became small when the volume of the lung was near total lung capacity. CONCLUSION: Changes in lung volume have different effects on changes in lung density in dependent and nondependent parts of the lung. The largest changes in lung density occur in the dependent regions. The difference in density between dependent and nondependent lung regions is smallest for lung volumes near total lung capacity. These findings may be useful as a baseline for interpreting CT measurements of regional lung density in suspected cases of lung disease, which would alter the physical density of lung tissue. Our results also suggest that measurements near total lung capacity should be included.

Adult↗
PubMed1993

Tuberculosis of the adrenal glands: diagnosis by CT-guided fine needle biopsy.

Bilateral adrenal masses were found in a 64-year-old man with pulmonary tuberculosis and a pulmonary mass lesion suspicious for carcinoma. CT-guided fine needle biopsy of the left adrenal gland revealed tuberculosis. Adrenal metastases were thus excluded and probably Addison's disease, considered to be a potential complication of adrenal tuberculosis, could be prevented.

Adrenal Gland Diseases↗
PubMed1993

Total respiratory impedance and early emphysema.

It can be postulated that patients in early stages of pulmonary emphysema have normal values of total respiratory resistance and reactance. The purpose of this study was to investigate whether pulmonary emphysema, detected functionally by a decrease of the single breath diffusing capacity (DLCO) by at least 25% of predicted, and an increase of the static lung compliance (CLst) by at least 50% of predicted, can be accompanied by normal values of respiratory resistance (Rrs) and reactance (Xrs), measured between 2 and 24 Hz by the forced oscillation technique. In a prospective study, we determined CLst in 26 patients, who had been selected on the basis of normal values of Rrs and Xrs, and a DLCO of less than 75% of predicted. In 17 of these patients, CLst was more than 150% of predicted. Since there were only minor abnormalities on routine lung function tests and chest X-ray, it is likely that these patients presented early emphysema. In the nine other patients, CLst was within normal limits: four suffered from interstitial lung disease; the remaining five were probably in a preliminary stage of early emphysema. In conclusion, early emphysema should systematically be considered as the first diagnosis in patients with normal values of Rrs and Xrs, and a decrease of DLCO. Onset of interstitial lung disease is a possible alternative.

Female↗
PubMed1992

The role of thiol oxidation in Cobalt(II)-induced toxicity in hamster lung.

Exposure of lung tissue to Co(II) ions both in vivo and in vitro results in toxicity, a relatively early event of which is the oxidation of cellular glutathione. In this study we have attempted to delineate the relationship between this oxidation of glutathione and the subsequent development of cellular dysfunction. Simultaneous incubation with H2O2 potentiated Co(II)-induced increases in both levels of oxidized glutathione (GSSG) and the activity of the pentose phosphate pathway in hamster lung slices. This effect was initially synergistic and, thereafter, both parameters were maintained at significantly greater levels than with either treatment alone throughout the incubation period until the onset of detectable cellular dysfunction. When dysfunction occurred, however, it was not quantitatively increased by the co-treatment over that occurring with CoCl2 alone. Similarly, pretreatment of slices with the glutathione reductase inhibitor 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) potentiated the Co(II)-induced increase in levels of GSSG. However, this effect was again not associated with an enhancement of cell dysfunction. Since the Co(II)-induced cell damage appeared not to be related directly to the oxidation of glutathione, the quantitative significance of the latter was investigated by comparison with the known oxidant tert-butyl hydroperoxide (t-BOOH). At a concentration of 100 microM, t-BOOH caused an increase in the concentration of GSSG in BCNU-pretreated lung slices which was comparable to that after treatment with Co(II)/H2O2 or CO(II)/BCNU. None of these treatments resulted in a loss of protein thiols. Furthermore, in contrast to Co(II), t-BOOH/BCNU treatment did not result in impaired cell functions. However, at a t-BOOH concentration of 250 microM, t-BOOH/BCNU treatment caused a significantly greater increase in the level of GSSG than that caused by the previous treatments and was associated with both a loss of protein thiols and increased cell dysfunction. We have concluded from these data that under our experimental conditions, Co(II)-induced cell dysfunction is not a consequence of oxidation of cellular glutathione. The reason for this appears to be that the extent of glutathione oxidation by Co(II) even at a concentration which induces cell dysfunction is not of sufficient magnitude to result in the oxidation of protein thiol groups, an event which is likely to constitute the critical consequence of glutathione oxidation in the toxic process.

Animals↗
PubMed1992

Lung injury induced by paraquat, hyperoxia and cobalt chloride: effects of ambroxol.

The effects of the surfactant stimulating drug ambroxol were studied in rats given paraquat (PQ, 15 mg/kg, s.c.), intratracheal cobalt chloride (CoCl2, 2.5 or 1.25 mg Co/kg) or exposed for 2 days to oxygen (greater than 95% O2). Ambroxol (50 mg/kg, i.p., twice daily) was given as a pretreatment for 4 days, or up to 7 days following pneumotoxic administration. Besides body weight evolution and lethality, various pulmonary indices were measured 2 days (O2) or 3 days (PQ and CoCl2) and 7 days after pneumotoxic treatment: wet and dry lung weight, total cell count, distribution of inflammatory cells and lactate dehydrogenase in bronchoalveolar lavage fluid, and histological damage assessed by a semiquantitative injury score. Neither form of ambroxol treatment prevented the toxicity of any of the pneumotoxic agents. The use of a combination of different indices of lung damage showed that different pneumotoxic agents may cause quite distinctive patterns of injury.

Ambroxol↗
PubMed1992

Relationship between axial motion and volume displacement of the diaphragm during VC maneuvers.

During semistatic inspiratory and expiratory vital capacity (VC) maneuvers, axial motion of the diaphragm was measured by lateral fluoroscopy and was compared with diaphragmatic volume displacement. Axial motion was measured at the anterior, middle, and posterior parts of the diaphragm, and the mean of these measurements was used. The volume displacement was calculated in two ways: first, from respiratory inductive plethysmograph-(Respitrace) derived cross-sectional area changes of rib cage and abdomen (Vdi,RIP) by means of a theoretical analysis described by Mead and Loring (J. Appl. Physiol. 53: 750-755, 1982) and, second, from fluoroscopically measured changes in position and anteroposterior surface of the diaphragm (Vdi,F). A very good linear relationship was found between Vdi,RIP and Vdi,F during inspiration as well as expiration (r greater than 0.95), indicating that the analysis of Mead and Loring was valid in the conditions of the present study. The diaphragmatic volume displacement (active or passive) accounted for 50-60% of VC. A very good linear relationship was also found between mean axial motion and volume displacement of the diaphragm measured with both methods during inspiration and expiration (r greater than 0.98). Our data suggest that, over the VC range, diaphragmatic displacement functionally can be represented by a pistonlike model, although topographically and anatomically it does not behave as a piston.

Adult↗
PubMed1992

Ventilatory effects of acetazolamide in cats during hypoxemia.

In normoxemic cats, acetazolamide (ACTZ) has been shown to cause a large rise in ventilation (VE) but a decrease in peripheral chemoreceptor activity. The relative contribution of the peripheral chemoreceptors to ventilation is higher during hypoxemia than during normoxemia. Therefore, what are the effects of ACTZ during steady-state hypoxemia? The aims of this study in anesthetized cats were 1) to study the effect of ACTZ (50 mg/kg iv) on mean hypoxemic [arterial PO2 (PaO2) approximately 6 kPa] ventilation and 2) to study the effect of ACTZ on the isocapnic hypoxic ventilatory response. In the first study, in six cats with an inspiratory CO2 fraction of 0, ACTZ led to an insignificant rise in mean VE of 119 ml.min-1.kg-1 after 1 h. In five other cats maintained at an inspiratory CO2 fraction of 0.015, ACTZ resulted in a significantly larger response in VE (268 and 373 ml.min-1.kg-1 after 1 and 2 h, respectively). In the second study, before infusion in five cats, an isocapnic fall in mean PaO2 from 13 to 4.7 kPa led to a significant rise in mean VE of 385 ml.min-1.kg-1; 1 h later, the response (at the same mean alveolar PCO2) was reduced to an insignificant rise of 38 ml.min-1.kg-1. Before infusion four other cats showed a significant rise in mean VE of 390 ml.min-1.kg-1 when mean PaO2 was lowered isocapnically from 12.4 to 6.8 kPa; 2 h after infusion, an isocapnic fall in mean PaO2 from 13.9 to 7.2 kPa led to an insignificant rise of 112 ml.min-1.kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗
PubMed1992

Survey of cobalt exposure and respiratory health in diamond polishers.

This cross-sectional study was undertaken after the discovery of cobalt-related fibrosing alveolitis and bronchial asthma in diamond polishers occupationally exposed to cobalt. A total of 194 workers from 10 diamond polishing workshops and 59 workers from three other workshops from the diamond industry (control subjects) were studied; a questionnaire was administered and spirometry was performed. Cobalt exposure was assessed by environmental air sampling using both area and personal sampling and by measuring urinary cobalt concentration. When considered on a workshop basis, these environmental and biologic indices of exposure correlated well with each other. These measurements led to the definition of three cobalt exposure categories: a no exposure group, a low exposure group, and a high exposure group. The high exposure was, however, still below the present threshold limit value for cobalt (50 micrograms/m3). Spirometry showed that indices of ventilatory function (FVC and FEV1) were significantly (p less than 0.05) lower in the group with the highest exposure to cobalt. These differences were not due to differences in smoking habits. The results were confirmed when the data were analyzed by covariance analysis of lung function indices against smoking status, taking mean cobalt exposure in each workshop as a covariate, and when the data were analyzed by multiple regression analysis. This analysis showed that cobalt exposure correlated with decreased pulmonary function. Our results suggest that, during diamond polishing, exposure to cobalt at levels below the current threshold limit value is associated, on a group basis, with measurable effects on lung function parameters. The relationship between these cross-sectional epidemiologic findings and the occurrence of overt lung disease in diamond polishers remains to be established.

Air Pollutants, Occupational↗
PubMed1992

Four-stage tuberculin testing in elderly subjects induces age-dependent progressive boosting.

We administered four sequential tuberculin skin tests (5 TU, PPD) with intervals of one week to 223 subjects older than 65 years of age to evaluate whether elderly subjects demonstrated progressive boosting. Indurations of at least 10 mm with increases of at least 6 mm (over the previous test) were considered significant reactions, and these were found in 29 percent of the subjects after test 1, in 43 percent after test 2, in 53 percent after test 3, and in 57 percent after test 4 (p less than 0.05), ie, only about 50 percent of all the positives were detected after the first test. The percentage of positive reactors was inversely related to age (p less than 0.001), yet this age-dependent difference decreased with increasing number of tests. For the 65- to 74-year-old age group, 44 percent reacted positively after the first test and after three tests almost a plateau of 65 to 70 percent positive reactors was reached, suggesting that a minority only of about 30 to 35 percent of these geriatric patients might have outlived their bacilli or were never infected. For the 75- to 84-year-old age group, 24 percent reacted after the first test and 55 percent reacted after the fourth one. For the older than 85-year-old age group, 19 percent positive reactors were found after the first test and 46 percent were found after the fourth test, without clear-cut leveling off toward a plateau value, suggesting that additional tests would induce further boosting. Mean diameters of positive reactions were 15 to 24 mm, and were mostly at least 12 mm larger than in the previous tests. These data support the hypothesis that the negative tuberculin reaction, which is often found in elderly subjects, is mainly due to the failing immune response to tuberculin antigen that can be restored progressively by repeated administrations. These findings, furthermore, emphasize that especially in elderly, care should be taken not to interpret a boosting reaction as a conversion and especially that neither a two-step testing as recommended by the ATS and CDC (Am Rev Respir Dis 1990; 142:723-35) nor even a four-step testing may suffice to detect all positives in this type of population.

Aged↗
PubMed1992

Measurement of lung density by means of quantitative CT scanning. A study of correlations with pulmonary function tests.

In recent years, much attention has been given to the role of CT in detecting and quantitating pulmonary emphysema. We measured CT lung density in 45 patients undergoing a diagnostic work-up and compared this with pulmonary function tests. The CT lung densities measured with the sector method and with the whole lung method were very highly correlated with each other (r = 0.96, p less than 0.001), and measurements at TLC systematically gave a lower density than those at FRC (p less than 0.001). Also, CT density measurements at TLC and even more so at FRC correlated well with pulmonary function indices of airway obstruction and of hyperinflation, but not with indices that are considered more specific for emphysema (single breath DCO, static lung compliance) We conclude that CT lung-density gives a good reflection of the degree of hyperinflation, ie, enlargement of distal airways, but is not sensitive to detect whether or not this is associated with emphysema.

Female↗
PubMed1992

Pleuropulmonary changes during treatment of Parkinson's disease with a long-acting ergot derivative, cabergoline.

A patient with Parkinson's disease, initially treated with bromocriptine and subsequently with cabergoline, developed progressive pleuropulmonary abnormalities during the latter therapy. These lesions even worsened for some weeks after interruption of cabergoline, which may possibly be related to the prolonged action of this drug. Thus cabergoline may cause similar pleuropulmonary abnormalities to bromocriptine.

Bromocriptine↗