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Biomedical subjects

P Rohdewald

Publications and source records attributed to P Rohdewald.

At least 73 records · Page 4Linked to original sources
PubMed1980

[Quantification of the attenuation of pain sensation through evoked potentials after the application of mild analgesics (author's transl)].

Evoked potentials resulting from stimulation of tooth pulp with rectangular impulses were chosen for the indication of the analgesic activity of mild analgesics. If the stimuli were perceived subjectively as equally painful, the amplitudes of the evoked potentials were intraindividually well reproducible. The results are reproducible within one day as well as on different days. According to the large interindividual variation in the amplitude of the evoked potentials, the percentual reduction of the amplitude was a better measure for the analgesic action than the absolute height of the signal. Interindividually, the latencies have shown clear differences whereas they were reproducible for the individuum. The curves for: 1. The percentual reduction of the evoked potentials 2. The diminuation of the subjective pain response 3. The increase in the sensitivity threshold after the application of the drug were principally similar. The results indicate, that the evoked potentials may represent a more sensitive measure of experimentally induced pain in subjective methods.

Acetaminophen↗
PubMedDate not supplied

Pharmacokinetics of prednisolone after high doses of prednisolone hemisuccinate.

Prednisolone in the form of its hemisuccinate was given intravenously in two different doses (1200 mg and 75 mg). Plasma levels of the ester and prednisolone were measured and pharmacokinetic parameters were calculated. The results indicate a dose-dependency in the pharmacokinetics of both hemisuccinate and the free alcohol. For the high dose 8 per cent of the administered ester was found unchanged in the urine indicating incomplete conversion of the pro-drug. Comparison with previous studies leads to the conclusion that prednisolone shows doubled non-linear pharmacokinetics with higher total body clearance in the medium dose range than in the low and high dose range. Volume of distribution changes accordingly, but overall elimination rate remains remarkably constant. Saliva levels of prednisolone were low and agree reasonably well with calculated plasma concentrations of free, non-protein-bound prednisolone. No prednisolone hemisuccinate was found in saliva.

Adult↗
PubMedDate not supplied

Pharmacokinetics of dexamethasone and its phosphate ester.

Dexamethasone in form of its phosphate was given intravenously in two different doses (1.5 mg kg-1 and 15 mg). Plasma levels of the ester and dexamethasone were measured and pharmacokinetic parameters were calculated. The results indicate no dose-dependency of the pharmacokinetic parameters in the investigated range for dexamethasone. Conversion from the prodrug to the active form was rapid; maximum dexamethasone plasma concentrations were reached after 10 min. The results were verified by dexamethasone level monitoring in patients after chronic dosing. Predicted and achieved steady state levels agreed well.

Adult↗
PubMedDate not supplied

Pharmacokinetics and dose linearity testing of methylprednisolone phosphate.

The pharmacokinetics of methylprednisolone and methylprednisolone phosphate were investigated after intravenous administration of methylprednisolone phosphate to six healthy subjects at seven different doses between 16 and 1000 mg. Plasma, urine, and saliva were analyzed for methylprednisolone and methylprednisolone phosphate. Furthermore, endogenous hydrocortisone was measured in plasma. No non-linearity in the total body clearance of methylprednisolone phosphate or methylprednisolone could be detected. The average elimination half-life for the prodrug was 3.7 min indicating rapid hydrolysis. After 15 min more than 90 per cent of the phosphate has been hydrolyzed. No prodrug could be detected in saliva; very little of the ester (average 0.9 per cent of the dose) was excreted unchanged into the urine. Methylprednisolone is formed rapidly. The total body clearance was 21 1h-1, the terminal half-life 2.8 h. In the post-distribution phase methylprednisolone levels in saliva went parallel to plasma levels. The mean saliva/plasma ratio was 0.22. An average of 5.2 per cent of the dose was eliminated into the urine in the form of methylprednisolone. Hydrocortisone suppression was dose-dependent. For doses above 125 mg hydrocortisone levels were significantly lowered after 24 h. For doses above 500 mg the suppression was still significant after 48 h. The results indicate a rapid and predictable in vivo conversion of methylprednisolone phosphate to its active form methylprednisolone.

Adolescent↗
PubMedDate not supplied

Dose-dependent pharmacokinetics of metabolites of dipyrone in saliva.

Metabolites of dipyrone have been determined in the saliva of 18 volunteers following the oral intake of 0.5 g, 1.0 g, 1.5 g, 2.0 g and 2.5 g dipyrone. High concentrations were measured for N-methyl-aminoantipyrine (MAA), the other analgetic active metabolite, 4-aminoantipyrine was found in minor quantities only. N-formyl-antipyrine was not present in the saliva of some volunteers after low doses but could be determined following the intake of doses from 1.5 g - 2.5 g in saliva of all volunteers. N-acetyl-antipyrine appears late in saliva, acetylation rates varied greatly interindividually. Concentrations of the metabolites in saliva mimic the respective non-protein bound fraction in plasma found by other authors.

Adult↗
PubMedDate not supplied

Venous ulcers: microcirculatory improvement and faster healing with local use of Pycnogenol.

Chronic venous insufficiency (CVI) causes a well-defined microangiopathy described as venous hypertensive microangiopathy (VHM) leading to venous ulcerations. VHM is mainly observed in the distal part of the leg, in the perimalleolar region. In VHM edema is the consequence of increased capillary pressure and reduced local clearance, and this affects local perfusion. The healing of venous ulcers is usually very slow. Many treatments are available, but there is still no standard. Oral Pycnogenol is effective in venous disease and particularly in controlling edema. The aim of this study was the evaluation of the local effects of Pycnogenol on ulcers healing associated with venous hypertension. The study lasted 6 weeks including 18 patients (16 completed the study) with venous ulcerations. The oral treatment with Pycnogenol was compared with a combination treatment including oral and local treatment. In subjects treated with the combination treatment (oral and local), venous ulcers healed better (there was a faster reduction in ulcerated area) in comparison with oral treatment only. According to this pilot study Pycnogenol appears to have an important role in local treatment of venous ulcers improving healing and signs/symptoms.

Administration, Cutaneous↗