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Biomedical subjects

G W Sybrecht

Publications and source records attributed to G W Sybrecht.

At least 73 records · Page 4Linked to original sources
PubMed1993

The muscarinic M1-receptor-selective antagonist, telenzepine, had no bronchodilatory effects in COPD patients.

In a double-blind, placebo-controlled, randomized, cross-over trial, we studied the effects of the muscarinic M1-receptor-selective antagonist (+/-)-telenzepine (3 mg orally at 6 p.m. for 5 days) in 21 patients with chronic obstructive pulmonary disease (COPD). At enrollment all patients showed at least a 50% decrease in airway resistance (Raw) after inhalation of 400 micrograms fenoterol or 200 micrograms oxitropium bromide. Telenzepine did not have a significant effect on forced expiratory volume in one second (FEV1) or forced vital capacity (FVC). Also, no significant changes could be detected in daily spirometric profiles or Raw. The results indicate that short-term treatment with the M1-selective antagonist, telenzepine, does not improve airway function in COPD patients, at least after administration by the oral route.

Airway Resistance↗
PubMed1991

Endoscopic ultrasonography of the mediastinum in the diagnosis of bronchial carcinoma.

Thoracic computed tomography (CT) is an essential component in the preoperative staging of bronchial carcinomas as is mediastinoscopy (MSC) in cases of mediastinal lymphoma. It is known that endoscopic ultrasonography (EUS), as a new diagnostic procedure, can predict lymph-node involvement in cases of tumors in the upper gastrointestinal tract with an 80% probability. In a prospective study, we examined whether EUS could be used to ascertain the presence of mediastinal lymph nodes in cases of bronchial carcinoma. Since 1990, therefore, 32 patients with operable non-small-cell bronchial carcinoma have been examined with an Olympus-Aloka EU-M2 or EU-M3 (frequency 7.5 and 12 MHz) in addition to routine diagnostics. The graded cross-sections of lymph-node dissections obtained during subsequent surgery served as evidence as to the true or false prognosis of the lymph-node status. Endoscopic ultrasonography identifies the presence and estimates the size of subcarinal, tracheobronchial, paraortal and paraesophageal lymph nodes better than computed tomography. Lymph nodes lying behind organs containing air (pretracheal lymph nodes) cannot be identified by ultrasonography. Lymph-node involvement was correctly identified by EUS in 72% of the cases, and the specificity was 86%. The poor sensitivity, at 67%, is explained by the high proportion (37%) of patients with anthracosilicosis, as the latter produces the same echo pattern as malignant infiltration. In 47% of all the cases, CT showed enlarged mediastinal lymph nodes which were not actually infiltrated in 67%. Of these lymph nodes, 33% could be classified as definitely free of metastases on the strength of their echo pattern, the rest were inflamed or really infiltrated by metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchial Neoplasms↗
PubMed1991

Individualization of theophylline dosage: a Bayesian method evaluated in patients with once-daily dosing.

A Bayesian drug dosing program was prospectively evaluated in 16 hospitalized patients with obstructive respiratory disease treated with a novel sustained-release preparation Euphylong. Theophylline was given as a single evening dose. By means of the Bayesian method, the early morning peak was predicted from a steady-state theophylline serum level determined at 8:00 a.m. The prediction errors were in all cases within a clinically acceptable range (mean prediction error +/- standard deviation: -0.2 +/- 1.3 mg/L). The results were compared with predictions based on steady state theophylline serum levels at 8:00 p.m. The prediction errors observed were on average greater than the prediction errors based on the serum levels at 8:00 a.m. (-0.6 +/- 2.5 mg/L). These findings suggest that the Bayesian method is useful for dosage predictions in patients treated once a day with Euphylong.

Adult↗
PubMed1990

Management of chronic airway obstruction: theophylline--is it still necessary?

Theophylline is a second-line drug for the symptomatic treatment of obstructive pulmonary diseases. It appears to be of particular value in the treatment of the more severe cases of airway obstruction. The likelihood of a therapeutic benefit and the safety of drug therapy can be increased markedly by an individually optimized theophylline therapy, that is, individual dosage and time of dosing, and monitoring the serum concentrations.

Airway Resistance↗
PubMed1990

[Characterization of platelet-activating factor (PAF)-receptors in neutrophilic and eosinophilic granulocytes].

It has recently been shown that the triazolodiazepine WEB 2086 inhibits the platelet-activating factor (PAF)-induced platelet aggregation, bronchoconstriction (J. Pharmacol. Exp. Therap. 1987; 241:974) and microvascular leakage (Br. J. Pharm. 1987; in press) in guinea pigs. In the present study we have determined the PAF antagonistic properties of WEB 2086 in human neutrophil and eosinophil leukocytes. In addition, we have characterized [3H] WEB 2086 as a radioligand in direct binding experiments with these cell types. PAF increased the beta-glucuronidase release from neutrophils with an EC50 of 138 nM. WEB 2086 caused a concentration-dependent inhibition of this PAF effect with an inhibition constant (Ki) of 11.9 nM. Binding of [3H] WEB 2086 to neutrophils was specific, reversible and saturable with a dissociation constant (KD) of 18.9 nM and a maximal number of binding sites of 40000 sites per cell. The characteristics of the binding sites were identical to those of PAF receptors. In human eosinophils PAF induced an increase in lucigenin-enhanced chemiluminescence with an EC50 of 2.5 nM. WEB 2086 competitively inhibited this response with a Ki of 16.4 nM. [3H] WEB 2086 bound to eosinophils with a KD of 18.5 nM, which is in good agreement with the Ki from the functional studies. Our results show that WEB 2086 is a potent and specific antagonist of PAF in human neutrophils and eosinophils. Also, [3H] WEB 2086 appears to be a suitable antagonist radioligand for labelling of PAF receptors in these inflammatory cells. WEB 2086 should be of value in further elucidation of the role of endogenous PAF in asthma through activation of inflammatory cells recruited to the lung.

Azepines↗
PubMed1990

[Indications for artificial ventilation in status asthmaticus, adult respiratory distress syndrome and pneumonia].

Mechanical ventilation is indicated in acute respiratory failure, especially in so-called pump failure as occurs in status asthmaticus, pneumonia and ARDS due to respiratory muscle fatigue. Using clinical parameters (inspiratory paradox, respiratory alternans), together with blood gas analysis and chest X-ray morphology, the indication can be established on a rational basis. The aims of therapy are tissue oxygenation and cure of the underlying disease which has led to respiratory failure. By adapting ventilator settings to the respiratory mechanics of the individual patient, complication due to barotrauma can be avoided. Respiratory muscle rest can be assessed by monitoring tracheal pressure time curves. Unconventional methods using very small t idal volumes and very high frequency so far have no clearcut indications, as they are still investigational.

Asthma↗
PubMed1990

First-time treatment with steroids in bronchial asthma: comparison of the effects of inhaled beclomethasone and of oral prednisone on airway function, bronchial reactivity and hypothalamic-pituitary-adrenal axis.

In a double-blind cross-over study of 12 asthmatic patients the effects of 1,000 micrograms.day-1 beclomethasone dipropionate (BDP) on airway function, bronchial reactivity and hypothalamic-pituitary-adrenal (HPA) axis have been compared to those of 15 mg.day-1 oral prednisone (PRD). None of the patients had ever received corticosteroids before. Fourteen days treatment with either of both steroids improved airway function, both subjectively and objectively. Both steroids slightly reduced the responsiveness to histamine. PRD suppressed the corticotrophin-releasing factor (CRF) stimulated cortisol release more than BDP did, whereas there was no significant change in adrenocorticotrophic hormone (ACTH) release. The results indicate that short-term treatment with 1,000 micrograms.day-1 BDP reduces bronchial hyperreactivity (BHR) in asthmatic patients, whilst having subtle effects on HPA axis.

Administration, Inhalation↗
PubMed1990

[Dose titration with Euphylong following prior determination of serum concentration in the steady state].

Euphylong is a theophylline preparation with new galenic slow-release design (micropellets in a capsule), developed for daily single-dose administration in the evening. It has been shown that the majority of patients with bronchial asthma, chronic obstructive bronchitis or emphysema who receive a single evening dose of Euphylong have a theophylline serum concentration that remains within the therapeutic range for 24 hours when the theophylline serum concentration measured at 8 a.m. under steady-state conditions is found to lie within the therapeutic range.

Adult↗
PubMed1990

[The histamine provocation test: are 1 second capacity and specific conductance competing or complementary measurement values?].

We tested criteria for the decision, whether a provocation challenge with histamine is positive. The combination of spirometry and bodyplethysmography by the condition sGaw less than or equal to 0.04 x PC-FEV overcomes the contradictions due to conventional criteria as PC-FEV greater than or equal to 20% or PC-sGaw greater than or equal to 50%.

Airway Obstruction↗