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Biomedical subjects

H Matthys

Publications and source records attributed to H Matthys.

At least 91 records · Page 5Linked to original sources
PubMed1994

Modulatory role of protein kinase C on the signal transduction pathway utilized by platelet-activating factor in eosinophil activation.

To determine the role of protein kinase C (PKC) in the signal transduction in eosinophil pathways, we have assessed the effects of the phorbol ester phorbol 12-acetate 13-myristate (PMA) on guinea pig peritoneal eosinophils challenged with platelet-activating factor (PAF). Pretreatment with PMA completely inhibited the PAF-induced release of eosinophil peroxidase (EPO) and superoxide anions and the rise in intracellular Ca2+ concentration ([Ca2+]i), with IC50s of 2 to 10 nM. This inhibition was reversed when the cells were preincubated with the PKC inhibitor staurosporine for 5 min before the addition of PMA. Staurosporine also inhibited PAF-induced EPO release but not the rise in [Ca2+]i. The inactive ester 4 alpha-phorbol 12,13-didecanoate had no inhibitory effect on eosinophil activation. Finally, PMA inhibited the binding of the PAF antagonist [3H]WEB 2086 to intact eosinophils. Taken together, these data suggest that PKC may have a physiologic role in regulating PAF-induced eosinophil responses through expression of PAF receptors on the cell surface.

Alkaloids↗
PubMed1994

Pulmonary immune cells in health and disease: the eosinophil leucocyte (Part II).

The second part of this review on eosinophils focuses on biological cell functions and surveys the various deleterious mechanisms involved in the eosinophil-dominated inflammatory reaction. It discusses the possible pathogenic role of eosinophils in several eosinophil-related diseases, such as parasitic infections, interstitial lung disorders and bronchial diseases, such as parasitic infections, interstitial lung disorders and bronchial diseases, graft rejection, vasculitic granulomatous disorders, pleural effusion, and bronchogenic tumours. The final section of the article highlights the possible recent pharmacological and future therapeutic approaches in modifying eosinophil recruitment and function.

Eosinophils↗
PubMed1994

[Cell biology and function of eosinophilic granulocytes in immunologic inflammation].

In recent years, increasing evidence has accumulated to suggest that the eosinophil represents a potent cytotoxic effector cell which plays a key role in the pathogenesis of pulmonary diseases as well as other human disorders. Beside contributing to antiparasitic host defense, eosinophils can prove detrimental to a number of host organs and tissues via release of their preformed basic proteins as well as de novo generated lipid mediators or oxygen radicals. Eosinophil effector functions are stimulated by certain lipid mediators and cytokines released by other cells in the course of active disease. In addition to their effector functions, eosinophils may have other functions in immune responses. Synthesis and expression of class II proteins of the major histocompatibility complex (MHC) may enable eosinophils to serve as antigen-presenting cells, i.e. to the antigens that appear at mucosal surfaces. In addition to collaborative interactions with lymphocytes, CD4-expressing eosinophils may elaborate cytokines that can effect cells within their tissue milieu. In conclusion, the evolving understanding of eosinophils indicates that eosinophils may not only serve as end-stage effector cells but also interact cooperatively with other cellular tissue elements in related diseases.

Asthma↗
PubMed1994

Accuracy of nine commercially available pulse oximeters in monitoring patients with chronic respiratory insufficiency.

9 pulse oximeters (BIOX-III, Nellcor 250, Jaeger CNS, Micro2), Pulsox-8, Oxycount, PulsOXImeter, PalcoLabs and Pulsox-7) were studied in 90 COPD patients. The transcutaneus oxygen saturation (SaO2%) was compared with arterial oxygen saturation calculated simultaneously with drawn blood samples (AVL-995). The measurement of error distribution and the cumulative distribution function (CDF) of measurement errors allows ranking of the pulse oximeters, which can be divided in 3 groups. We conclude that the accuracy of the tested nine pulse oximeter does not enable precise absolute measurements, specially at lower oxygen saturation ranges.

Airway Obstruction↗
PubMed1993

Comparison of sputum-ECP levels in bronchial asthma and chronic bronchitis.

Eosinophil cationic protein (ECP) is a cationic protein secreted by eosinophils with toxic properties for the respiratory epithelium. Sputum-ECP levels have been shown to correlate inversely with airflow obstruction in asthma. In the present study we investigated whether ECP concentrations are different between asthmatic patients and patients with chronic bronchitis. Sputum-ECP concentrations from seven patients with bronchial asthma and seven patients with chronic bronchitis matched for FEV1 were compared (FEV1 Asthma: 66.1 +/- 29.0% of predicted; FEV1 Chronic Bronchitis: 65.2 +/- 33.3% of predicted; p = n.s.). Furthermore, sputum-ECP levels in 4 asthmatic patients with severe airflow obstruction and in 1 patient with chronic bronchitis were measured before and after initiation of a 7-day oral therapy with methylprednisolone 20 mg BID. Changes in sputum-ECP values were compared with changes in FEV1 in these 5 patients. Sputum-ECP levels and pulmonary function were measured as previously described (Am Rev Respir Dis 1992: 145: 604). Sputum-ECP levels from asthmatics were significantly elevated compared with patients with chronic bronchitis: asthma: 893.4 +/- 346.2 micrograms/l per g sputum; chronic bronchitis: 30.0 +/- 8.5 micrograms/l per g sputum (p = 0.002). The degree of airway obstruction correlated with the sputum-ECP levels in asthmatic (r = 0.76, p = 0.05), but not in the patients with chronic bronchitis (r = 0.24, p = n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

A new aerosol device for bronchial provocation tests.

A special new device for diagnostic (bronchoprovocation) and therapeutic aerosol application is described. It consists of a high quality nebulizer system combined with a 10-liter storage bag which serves as an aerosol 'conditioner' (saturated ambient temperature and pressure conditions) and as a holding chamber to increase the respirable aerosol fraction and hence pulmonary deposition (Pari Provocation Test I). It allows ten times better standardized pulmonary aerosol deposition compared with the generally used nebulizers for calculation of dose-response curves especially for asthma provocation and dilatation tests. If slow inspiratory vital capacity maneuvers are used, pulmonary deposition of about 100 mg aerosol is achieved in children and adults. This device is especially important when exact dosing (also for therapeutic reasons) is required in the expanding field of topical and systemic aerosol application to or via the lung.

Aerosols↗
PubMed1993

Platelet-activating factor-induced human eosinophil activation. Generation and release of cyclo-oxygenase metabolites in human blood eosinophils from asthmatics.

The spontaneous and stimulated generation of fatty acid cyclo-oxygenase pathway-derived products of arachidonic acid from highly purified (91.6 +/- 1.3%, n = 23) human blood eosinophils obtained from asthmatics were examined using combined gas chromatography/mass spectrometry. Under resting conditions, eosinophils spontaneously generated 0.24 +/- 0.10 pg prostaglandin E2 (PGE2), 0.51 +/- 0.20 prostaglandin D2 (PGD2), 0.35 +/- 0.10 pg prostaglandin F2 alpha (PGF2 alpha) and 8.5 +/- 2.2 pg thromboxane B2 (TXB2), the stable metabolite of TXA2 per 10(6) cells. In contrast, 6-keto-prostaglandin F1 alpha and 9 alpha,11 beta-prostaglandin F2 were not detectable. Stimulation of eosinophils with platelet-activating factor (PAF) for 5 min induced a two- to sixfold increase in the biosynthesis of prostanoids. More than 95% of the generated prostanoids were released into the surrounding medium. The response to PAF was inhibited by the PAF receptor antagonist WEB 2086 (1 microM). The fatty acid cyclo-oxygenase inhibitor, ibuprofen, abolished both the spontaneous and PAF-stimulated generation of prostanoids by eosinophils. LTB4, PMA and calcimycin also produced an increase in prostanoid production, whereas lyso-PAF, the PAF precursor and metabolite, failed to induce prostanoid generation over basal production. In conclusion, the results demonstrate that PAF potently activates human eosinophils to generate and release several fatty acid cyclo-oxygenase metabolites of the arachidonic acid pathway, with TXB2 being the most abundant. These data are in agreement with previous observations suggesting that PAF may be an important stimulus for prostanoid release by the eosinophil in allergic diseases such as asthma.

Asthma↗
PubMed1993

[Clinical experience with the Apnea Check System in screening for sleep apnea].

We examined 17 patients (3 female, 14 male) of 40 to 60 years of age suspected of suffering from sleep apnoea (SA) according to anamnesis and pulse oximetry, using the apnoea check system (AC) and by polysomnography (PS). AC measures the flow at the mouth and nose by means of thermistors and records the apnoea number, maximal duration of apnoea, and mean duration of apnoea (A mean). The PS-measured values: apnoea index (AI), maximal duration of apnoea (A max) and mean duration of apnoea (A mean) were taken to be equal to 100% and the AC-measured values were referred to these. AI (AC) was 76-577% of AI (PS). In 3 patients, AI (AC) was smaller than AI (PS), whereas in 14 patients it was greater. A max (AC) was 83-390% of A max (PS). In 11 patients A max (AC) was greater than A max (PS) and in 6 patients it was smaller. A mean (AC) was 56-223% of A mean (PS). In 9 patients A mean (AC) was greater and in 8 patients smaller than A mean (PS). PS had in 15 patients an AI > 10, in 2 patients < 10. In all patients, AC had an AI > 10. AC enabled identification of all patients suffering from sleep apnoea, and hence it appears to be suitable for screening. Further measurements in patients with AI < 10 will be necessary to examine the specificity.

Adult↗
PubMed1992

A prospective trial using salivary-theophylline levels to guide asthma therapy.

In three prospectively designed studies, first saliva (SA) samples were collected simultaneously with serum (SE) from 86 children who received slow-release theophylline (Th) b.i.d. for treatment of bronchial asthma. SA was collected with a standardized sampling procedure. Regression analysis revealed a close correlation between SE and SA-Th levels (r = 0.959; SE = 1.87 x SA + 0.05) and yielded a "therapeutic SA-Th range" of 5.8 to 10.7 mg/L. In 16 children the diurnal variation was then assessed by measuring 6 SA-Th levels within 24 hr, using the same sampling method. At 0, 9, and 24 hr SE-Th levels were also measured. The levels of SE-Th and SA-Th were again closely correlated (0.914 less than or equal to r less than or equal to 0.949) and both remained constant over the 24-hr period. In the third prospective trial only SA levels were used to monitor Th therapy in 50 asthmatic children. Seven days after starting therapy SA-Th levels were measured and then the Th dose was increased weekly until SA-Th levels above 5.8 mg/L were reached. The following day SE and SA samples were collected simultaneously and their Th levels compared. In 36 of the 47 children who completed the study therapeutic SE-Th levels (greater than or equal to 10 and less than or equal to 20 mg/L) were measured; in one patient it was greater than or equal to 20 mg/L, in 6 it was between 8.0 and 10 mg/L, and only 4 had SE levels less than 8.0 mg/L.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Morphology and density features of eosinophil leukocytes in eosinophilic pneumonia. A case report.

We compared the morphological characteristics and density properties of eosinophil leukocytes obtained from the blood and bronchoalveolar lavage fluid of a 29-year-old patient with chronic eosinophil pneumonia during exacerbation. The lavage eosinophils were significantly increased in size when compared with blood cells (surface area: 208 +/- 12 microns 2 versus 161 +/- 13 microns 2). Moreover, eosinophils contained slightly more granules (23.4 versus 20.7 per cell surface area), but no difference was found when the number was corrected for cell size. Electron microscopy revealed a loss of granule contents in eosinophils from both blood and bronchoalveolar lavage. Finally, 61% of the lavage eosinophils were hypodense (with a density less than 1.085 g/ml), whereas 96.3% of the blood cells were normodense. In conclusion, our data demonstrate that in chronic eosinophil pneumonia, eosinophils obtained from bronchoalveolar lavage and blood show differences in both their morphology and density, suggesting that eosinophils during migration into the lung may become activated.

Adult↗