Biomedical subjects

C Hens

Publications and source records attributed to C Hens.

4 recordsLinked to original sources

PubMed1998

[Requirements for product quality of theophylline sustained-release preparations].

In consideration of the narrow therapeutic range and the pharmacology of theophylline (CAS 58-55-9), the pharmaceutic quality of sustained release theophylline preparations should be monitored carefully. During the last few years, the following pharmacokinetic study programme was established as quality criterion to verify the safety and predictability of theophylline concentration-time profiles: bioequivalence from batch to batch, lack of relevant food interaction, lack of relevant gastrointestinal pH or surfactant effects on absorption, pharmacokinetic profile following once-a-day and twice-a-day application, and pharmacokinetics in high-clearance patients. Smooth, predictable and safe concentration-time profiles can be guaranteed exclusively for preparations which fulfill all these quality criteria. Only such high quality formulations allow to reduce or even avoid therapeutic drug monitoring and can be considered as safe and effective drugs for the chronic treatment of asthma.

Anti-Asthmatic Agents↗

PubMed1998

[The anti-inflammatory action of an oral sustained-release theophylline preparation. Results of a clinical pilot study with low dosages].

A pilot study in 14 patients with mild asthma was performed to study the anti-inflammatory efficacy of theophylline (CAS 58-55-9). At the start, during and at the end of a 3 months' treatment with oral sustained release theophylline and during 1 week thereafter, the influence on airway hyperreactivity and ECP (eosinophil cationic protein) serum levels was investigated. Airway responsiveness was expressed as the cumulative provocative dose of methacholine necessary to decrease FEV1 by 20% (PD20-FEV1). Data of 8 patients were suitable for evaluation. At a mean predose serum concentration of 6.5 mg/l, theophylline increased the mean PD20-FEV1 for methacholine from 151 micrograms (at start) to 332 micrograms (at the end of medication), and reduced the mean ECP serum concentration from 34.6 to 24.5 micrograms/l. Up to 1 week after theophylline treatment, the improvement of airway hyperreactivity compared to the baseline was maintained, whereas ECP-serum levels tended to increase. Thus, theophylline markedly attenuated airway hyperreactivity in patients with bronchial asthma at "subtherapeutic" serum theophylline concentrations as well as ECP serum concentrations, suggesting the anti-inflammatory efficacy of theophylline. These observations may have therapeutic implications in the treatment of patients with mild asthma. A slight improvement of lung function and dyspnoea, and a reduction of additional beta 2-bronchodilator use was also observed. Two patients only complained of slight nausea, tremor and restlessness.

Adult↗

PubMed1990

[Does COPD affect bone mineral content?].

In a retrospective study, 85 COPD patients not treated with steroids, and 78 who received steroid therapy, were compared with a control group of normal subjects (n = 126) matched for age and sex. The determination of the bone mineral content (BMC) was carried out with the aid of two-photon absorption measurement performed in the region of the lumbar spine L2-4 and of the neck of the femur. With respect to the distribution of the bone mineral content as a function of sex and pulmonary function reduction, the following results were obtained: 1. There are significant differences between men and women. The BMC is generally lower in women. 2. Significant differences are to be found between the normal subject group and the steroid-free group on the one hand, and the steroid-treated group on the other. The group receiving steroid treatment has appreciably lower BMC values. 3. There are statistically significant correlations between the severity of airway obstruction and the decrease in BMC both in steroid-treated and steroid-free patients.

Aged↗

PubMed1986

Radionuclides in detecting active granuloma formation. Gallium-67 scintigraphy and histopathology with autoradiographic findings.

Granuloma formation studies were performed on lungs of guinea pigs sensitized with FCA over 2 to 17 months. Prolonged time of sensitization revealed more granulomatous pulmonary tissue. An intravenous booster of FCA in the animals that had been sensitized for 3 months yielded enhanced granuloma formation within 5 days. The histopathology of these lungs was comparable with that seen in lungs of animals after 17 months of sensitization without booster. Enhanced local proliferation of macrophages, measured by [3H]thymidine incorporation and autoradiography, was seen in the lungs of the animals that had received boosters. Moreover, 67Ga scintigraphy was strongly positive in these animals. Scintigraphy of cell suspensions of pulmonary tissue from these animals showed that 67Ga was predominantly taken up (quantitatively as well as qualitatively) by the alveolar macrophages. Cell suspensions of sarcoidosis patients, prepared in the same way, showed only a low level of 67Ga uptake, one comparable to that of the pulmonary cell suspensions of the sensitized animals that had not received boosters. It is suggested that a negative scintigraphy in patients with chronic pulmonary granulomatous disorders could be (partly) explained by the absence of activated macrophages.

Animals↗