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Biomedical subjects

M Demedts

Publications and source records attributed to M Demedts.

At least 235 records · Page 13Linked to original sources
PubMed1975

Inflection point on transpulmonary pressure-volume curves and closing volume.

In 20 healthy subjects and 18 patients with bronchial obstruction, closing volume (CV) on single-breath nitrogen washout curves and inflection point (IP) on transpulmonary pressure-volume curves were recorded simultaneously during slow expiratory vital capacity maneuvers. IP and CV did not occur at identical lung volumes, IP being systematically larger than CV for small CV values. This discrepancy could not be attributed to an esophageal or mediastinal artifact. It is suggested that, though CV and IP both express "airway closure," their sensitivity to closure may differ: CV underestimates closure because of a dead space effect; the latter may vary individually. On the other hand, IP may not reflect the true beginning of closure, particularly when it occurs at higher lung volumes.

Adult↗
PubMed1975

Horizontal gradient in ventilation distribution due to a localized chest wall abnormality.

Horizontal gradients in the distribution of ventilation and of regional vital capacities, as well as a reversed vertical, esophageal pressure gradient, were observed in a patient with a unilateral painful chest wall lesion. The distribution abnormalities disappeared after surgical treatment. These findings suggest that the interdependency between chest wall and lungs, and within the latter, between lobes, is an important factor determining the regional distribution of ventilation and the pleural pressure gradient in man.

Bronchial Fistula↗
PubMed1975

Diagnostic value of blood pool and transmission scan in cardiovascular and tissue pathology of the thoracic midline.

We reviewed 48 records of combined blood pool and transmission scans, performed in the last three years for mediastinal masses and cardiomegaly. The purpose was to investigate the diagnostic value of this radioisotopic examination, and in particular to compare it with the roentgenographic examination. The accuracy of both methods in visualizing mediastinal tumors or tissue pathology was very similar. The scintigraphic examination was superior for the diagnosis of cardiovascular pathology. False negative results occurred more frequently than false positives, especially in cases of tumors and aneurysms.

Blood↗
PubMedDate not supplied

Lung volume reduction surgery (LVRS) for emphysema: initial experience at the University Hospital Gasthuisberg. Leuven LVRS Group.

Emphysema is a disabling disease, for which there is no curative therapy available today. Lung transplantation offers a valuable option for a very selected number of patients, however, due to the enormous organ shortage, only few patients can be offered such a therapy. Recently there has been important resurgence of interest in lung volume reduction surgery and as a consequence, we have embarked in such a program since may 1997. We have now performed unilateral lung volume reduction surgery in 29 emphysema patients (25 on the right and 4 on the left side). Twenty-four patients were already discharged home. There has been no perioperative mortality. The mean hospital stay was 19.8 +/- 11.4 days (range, 8-47 d). Twenty patients of whom we already have follow-up data during 6 months (m) form the further basis of this report. Six weeks after the procedure the FEV1 increased from 0.82 +/- 0.28 L (28 +/- 8%) to 1.05 +/- 0.39 L, a mean increase of 28%. There was a further increase of the FEV1 to a maximum of 1.06 +/- 0.42 L at 6 m, a mean maximum increase of 29% (p = 0.0046, ANOVA). Similarly, the FVC increased from 2.80 +/- 1.10 L to 3.15 +/- 1.00 L, a mean increase of 12.5%. A further increase was also obtained at 6 m and was 19.6% (3.35 +/- 1.05 L, p = 0.014, ANOVA). The maximum decrease in RV was obtained at 3 m (from 5.91 +/- 1.37 L to 4.37 +/- 0.85 L (p = 0.0001, ANOVA), a mean decrease of 26%. The maximum TLC decrease was demonstrated at 3 m (from 8.71 +/- 1.71 L to 7.60 +/- 1.56 L (p = 0.002, ANOVA), a mean decrease of 12.8%. Afterwards there was again a gradual raise of the TLC. The six minute walking distance increased from 231 +/- 31 m to 272 +/- 34 m (p = NS) after pulmonary rehabilitation and to 416 +/- 77 m at 3 m and 415 +/- 18 m at 6 m (p = 0.0002, ANOVA) after the operation. The quality of life (measured with a standardized questionnaire, the Nottingham Health Profile) improved significantly in several domains (e.g. mobility, pain, energy, emotions and social) at 3 m postoperatively. There was one late death (at 6 m) due to an unknown cause. The actuarial survival rate was therefore 100% at 3 m and 95% at 12 m. In conclusion, unilateral thoracoscopic lung volume reduction surgery is a new and safe treatment modality for patients suffering from severe end-stage emphysema. The objective and subjective improvement is marked and the mortality is very low. Rigid selection criteria are, however, necessary to be able to guarantee an optimal result.

Actuarial Analysis↗
PubMedDate not supplied

Registration of interstitial lung diseases by 20 centres of respiratory medicine in Flanders.

We report the results of a prospective registration of the prevalence of interstitial lung diseases by 20 centres of respiratory medicine in Flanders from January 1992 till July 1996. The 20 centres registered a total of 362 cases. Sarcoidosis (31% with inclusion of stage I, or 22% without stage I), idiopathic pulmonary fibrosis (20%), hypersensitivity pneumonitis (13%) and unclassified forms of interstitial lung diseases (9%) were the most often diagnosed diseases. The mean age of the patients was 52 +/- 17 (SD) years, but ranged from 32 +/- 10 years in histiocytosis X to 70 +/- 13 years in drug induced interstitial lung diseases. The male to female ratio was 1.3 but ranged from 2.3 in interstitial lung diseases due to inhalation of inorganic materials to 0.8 in interstitial lung diseases due to connective tissue disease. The diagnosis was considered certain in 60%, probable in 30% and possible in 10%. In 50% of the cases the diagnosis was proven by biopsy and the most often used biopsy technique was transbronchiolo-alveolar biopsy (40% of biopsies) followed by open lung biopsy (32%). At diagnosis vital capacity was 82 +/- 22% pred. (ranging from 92 +/- 19% in sarcoidosis to 71 +/- 24% in idiopathic pulmonary fibrosis) and CO-diffusing capacity was 77 +/- 19% pred. (ranging from 77 +/- 19% in sarcoidosis to 41 +/- 13% in drug induced pneumonitis). The regional frequency of interstitial lung diseases in Flanders varied widely and was not proportional to the regional distribution of the 20 contributing centres. In conclusion this registration provides interesting information on the occurrence and presentation of the different forms of interstitial lung diseases, although it may still underestimate the real prevalence and incidence of interstitial lung diseases.

Adult↗
PubMedDate not supplied

[Minocycline-induced pulmonary infiltration and eosinophilia].

A 90-year old woman with pulmonary infiltrates and eosinophilia caused by minocycline is described. Until now, in the English, French and Dutch literature only some 35 cases are known. The prognosis is good, especially after treatment with corticosteroids. This doesn't legitimate, however, the use of minocycline without a clear indication. This case again stresses the need for a careful history taking, especially regarding the intake of medications (like minocycline), when one is confronted with a diagnostic problem of pulmonary infiltrates and eosinophilia.

Aged↗
PubMedDate not supplied

Decrease in gamma-glutamyltransferase activity in rat type II cells exposed in vitro to hyperoxia: effects of the 21-aminosteroid U-74389G.

Although the effect of hyperoxia on antioxidant enzymes is well known, the effect of subtoxic levels of hyperoxia on gamma-glutamyltransferase (gamma-GT), involved in the degradation and uptake of extracellular GSH for intracellular GSH synthesis, is unknown. The aim of the study was to investigate (1) the effects of in vitro hyperoxia on gamma-GT activity of type II cells and (2) the effects of the lazaroid U-74389G and N-acetylcysteine (NAC) on the hyperoxia-induced changes in gamma-GT and antioxidant enzyme activities. At 48 h after isolation, rat type II cells were exposed for 2 days to air, 60% O2 or 85% O2 with or without 30 microM U-74389G or 100 microM NAC. After the exposure, the cells were harvested and assayed for superoxide dismutase (SOD), glutathione peroxidase (GPx), gamma-GT activity, and GSH levels. In another series of experiments 85% O2-exposed cells, with or without U-74389G, were used for Northern blotting of gamma-GT mRNA. Exposure to 60% O2 decreased gamma-GT and GSH by -47 and -34%, respectively, while SOD and GPx activities remained unchanged. After 85% O2-exposure gamma-GT decreased by -55%, SOD and GPx increased by +55 and +87%, respectively, while GSH decreased by -35%. NAC treatment decreased gamma-GT activity by -42% in the air-exposed cells. After 60% O2, U-74389G led to significantly higher gamma-GT (+117%) and GSH (+26%) while NAC only led to higher GSH (+28%) compared to the oxygen-exposed cells not treated with NAC or U-74389G. After 85% O2 U-74389G increased gamma-GT, SOD, and GSH by +72, +58, and +68%, respectively, while NAC only increased SOD (+49%) and GSH (+26%) compared to the oxygen-exposed cells not treated with NAC or U-74389G. The 85% O2 exposure, with or without U-74389G, had no effect on gamma-GT mRNA levels. The results show that hyperoxia decreases rat type II cell gamma-GT activity in vitro. This effect was not related to an altered regulation at mRNA level and it was not associated with the hyperoxia-induced decrease in intracellular GSH, since restoration of the GSH levels by NAC did not restore gamma-GT activity. The lazaroid U-74389G with vitamin E-like properties effectively prevented the decrease in gamma-GT and GSH, so that direct inactivation of the membrane-bound gamma-GT by hyperoxia is the most likely mechanism.

Acetylcysteine↗
PubMedDate not supplied

Switch to non-CFC inhaled corticosteroids: a comparative efficacy study of HFA-BDP and CFC-BDP metered-dose inhalers.

Inhaled corticosteroids, such as beclomethasone dipropionate (BDP), recommended for the treatment of persistent, mild, moderate, or severe asthma, have traditionally been administered via chlorofluorocarbon (CFC) propellant. The imminent phasing out of CFCs from pharmaceutical preparations due to the Montreal Protocol means patients will have to switch to a CFC-free alternative. One such preparation is hydrofluoroalkane-BDP (HFA-BDP), a press-and-breathe metered-dose inhaler. This 8-week, open-label, multicentre study assessed asthma control in patients switching from CFC-BDP to HFA-BDP (QVAR). Patients with asthma, stabilised on 400-1600 micrograms/day CFC-BDP, were randomised to HFA-BDP (354 patients; 75%) at half their current daily dose of CFC-BDP, or to CFC-BDP (119 patients; 25%). HFA-BDP efficacy was found to be equivalent to that of CFC-BDP in that no statistically significant difference was observed between the two groups in the mean change from baseline in a.m. PEF (95% CI within +/- 11 l/min). No statistically significant differences were observed between the two groups for increased asthma symptoms or acute asthma episodes. We conclude that asthma control was maintained over 8 weeks, with few asthma exacerbations, in patients switching from previous CFC-BDP therapy to HFA-BDP at half the dose.

Adrenal Cortex Hormones↗