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Biomedical subjects

H Wendt

Publications and source records attributed to H Wendt.

At least 37 records · Page 2Linked to original sources
PubMed1984

The pharmacokinetics of fluocortolone and prednisolone after intravenous and oral administration.

The pharmacokinetics of fluocortolone and of prednisolone were examined following a single intravenous injection of 5 mg and oral administrations of 10 and 20 mg to five healthy male volunteers. After intravenous injection the plasma levels of fluocortolone decreased biexponentially with half-lives of 9 +/- 5 min and 1.3 +/- 0.3 h. Total plasma clearance of fluocortolone was calculated to be 7.0 +/- 1.5 ml/min/kg. Oral administrations of fluocortolone revealed maximum plasma levels of 86 +/- 12 ng/ml (10-mg dose) and 174 +/- 34 ng/ml (20-mg dose) after 1.4 +/- 0.2 h. Intravenously administered prednisolone was rapidly distributed (t 1/2 alpha = 5 +/- 3 min) but more slowly eliminated from plasma than fluocortolone (t1/2 beta = 3.1 +/- 0.8 h). Correspondingly a total plasma clearance of 2.2 +/- 0.2 ml/min/kg was calculated. Oral administrations revealed maximum prednisolone plasma levels of 172 +/- 25 ng/ml (10-mg dose) and 278 ng/ml (20-mg dose) after 1.6 +/- 0.7 h. The absolute bioavailability of both corticosteroids was higher than 80% and independent of both dose levels investigated.

Administration, Oral↗
PubMed1983

Regeneration of hemofiltrate by anodic oxidation of urea.

Urea can be oxidized electrochemically in a chloride solution to carbon dioxide, water, and nitrogen. The microkinetics of this hypochlorite-mediated urea oxidation are elucidated. Based on this kinetic information, the optimal conditions and construction principles for an electrochemical reactor are deduced. The construction of a cheap, disposable oxidation cell and necessary auxiliary equipment are described. In vitro data are reported for urea removal. A 36-L volume was used to simulate a 60-kg patient; 18 L was recirculated through a 0.12-m2 oxidation cell. Within 3 h, 35 g urea could be removed from the system. The technical and economic possibilities as well as safety requirements for hemofiltrate regeneration to a reinfusable substitution solution by anodic urea oxidation are discussed critically. Although the process does not appear to be economically practical for discontinuous hemofiltration, it might be desirable for continuous (24 h/day) treatment.

Blood↗
PubMed1983

Plasma levels of dehydroepiandrosterone and 17 beta-estradiol after intramuscular administration of Gynodian-Depot in 3 women.

Gynodian-Depot is well suited for treatment of the characteristic symptoms accompanying the menopause in women. The plasma levels of prasterone and 17 beta-estradiol after intramuscular injection of Gynodian-Depot in women were studied using a radioimmunological method. The maximum active ingredient concentrations were found in the plasma of the subjects only a few days after administration. The depot action lasted on an average 14 days (17 beta-estradiol) and 18 days (prasterone) after administration, respectively. Prasterone enanthate is completely hydrolysed into the free steroid and the fatty acid.

Adult↗
PubMed1982

Further studies of the effects of inhaled glucocorticoids on pituitary-adrenal function in healthy adults.

We compared the effects of increasing doses of beclomethasone dipropionate (BDP) and fluocortin butylester (FCB) on several indices of pituitary-adrenal function in healthy adult subjects. Significant depression of urinary free cortisol excretion and the response to metyrapone was seen only at the highest dose (1600 mg/day) of BDP. This depression was not reflected by frequent measurement of the serum cortisol concentration. FCB used well in excess of its presumed therapeutic dose range showed no evidence of any effect on pituitary-adrenal function. These results confirm that at high doses BDP causes pituitary adrenal suppression. Differences from studies showing reduced adrenal function in children on BDP doses of 400 to 800 mg/day probably reflect differences in the dose per kilogram of body weight. Since the use of FCB was not accompanied by any adverse side effects or evidence of reduced pituitary-adrenal function, it may be a variable alternative for asthmatics who require high doses of inhaled glucocorticoid.

Administration, Intranasal↗
PubMed1981

Radioimmunoassay of plasma lisuride in man following intravenous and oral administration of lisuride hydrogen maleate: effect on plasma prolactin level.

The development of a sensitive radioimmunoassay for the determination of lisuride in plasma is described. The antiserum against lisuride-4-hemisuccinate-BSA was raised in rabbits. Using this method the plasma levels of lisuride were monitored following one intravenous (25 microgram) and two oral (100 microgram and 300 microgram) doses of lisuride hydrogen maleate in three female and three male volunteers (intra-individual comparison). The plasma prolactin was also determined by radioimmunoassay. Following i. v. injection, the concentration of lisuride declined in three phases, with half-lives of 5 min, 25 min and 2 h. The total plasma clearance of 800 +/- 250 ml X min-1 was in the range of "plasma flow" through the liver. In agreement with the high rate of biotransformation, the bioavailability of lisuride administered orally was 10% +/- 7% of the 100-microgram dose, and 22% +/- 7% of the 300-microgram dose. The plasma prolactin was lowered to 3%-18% of its pretreatment value depending on the route of administration and the dose. The reduction appeared to be short-lived and to be directly dependent on the plasma concentration of lisuride. Following intravenous injection, the prolactin level declined after a so far unexplained lag-time of 0.5 h.

Administration, Oral↗
PubMed1981

Characterization of a new potent heparin. 7th communication: A comparative study of a new potent heparin in human after i.v. application.

The anticoagulant effect of a new potent heparin was compared with commercial heparin after a single i.v. application in human subjects. Determinations of thrombin time, whole-blood clotting time, activated partial thromboplastin time and plasma heparin levels using factor Xa inactivation assay were performed 5, 10, 15, 30 and 60 min after application. The new potent heparin was 1.5 to 2.0 times more effective than commercial heparin per mg dry weight depending upon the coagulation tests used and the length of observation period. In addition, determinations of biochemical and haematological parameters, 24 h after heparin application indicated no signs of any adverse effect.

Adult↗
PubMed1981

[Current and prospective questions in psychiatry].

In order to establish relations appropriate to therapy between pathogenesis and pathoplastics of psychic disturbances, the psychiatrist requires a general medical education overlapping on many marginal fields. Topically and prospectively, psychiatry is faced with, for example, the following tasks: development of new conceptions of genetics, interdisciplinary research of early cerebral damage, of the systemic factor of psychosis and the psychosocial releasing factor, cutting of the dwelling time at a hospital, community-supported treatment and after-care. Availability of specialised establishments for oligophrenia and socially endangered persons. Construction of socially integrated care systems. Institutional and personal equality with other special fields.

Brain Damage, Chronic↗
PubMed1980

Thermographic analysis of skin test reaction using AGA thermovision.

The course of infrared thermography including isothermograms on the skin surface was investigated considering blood flow, redness of the skin and permeability of blood vessel, in the following skin reactions: 1. Intracutaneous injection of histamine and histamine liberator compound 48/80 increased the heat radiation. Local application of antihistamine externa which decreased the development of the urticarial histamine reaction, increased the infrared radiation of the skin surface. Combined injection of histamine or histamine liberators with antihistamines in a sufficient dosis (1:1 respectively 4:1) diminished also the heat radiation in addition to the urticarial reaction. 2. The Pyrexal reaction of the skin with early erythema and later papule development shows an equivalent picture in the AGA Thermovision. The pretreatment shows an equivalent picture in the AGA Thermovision. The pretreatment of the skin with corticosteroid ointments shows a corresponding lowering of the erythema, of papule development as well as of heat radiation. The blanching of corticosteroids after occlusive dressing is difficult to recognize by the isotherms of AGA Thermovision. 3. Allergic reactions of the immediate type show, corresponding to the wheal eruption, a marked increased of heat radiation combined with a projection of the enlarged veins on the skin surface. 4. Allergic reactions of the delayed type are combined with a definite elevation of heat radiation of the skin. The area of a positive skin test with allergic eczematous reaction shows a distinct elevation of ann infrared radiation. Although the allergic skin area which was substantiated by a positive skin test was no longer visible, a distinct infrared radiation could be detected. Preventive treatment of the test area of skin patch-testing with corticosteroids inhibits the heat radiation even if the allergic eczematous reaction occurs faintly. The thermographic analysis of the different skin test reactions complied with the morphological aspects of the reaction.

Dermatitis, Atopic↗
PubMed1980

Differences and similarities among circadian characteristics of plasma renin activity in healthy young women in Japan and the United States.

A circadian rhythm of plasma activity (PRA) was demonstrated for both Japanese and North American women, the latter mostly Caucasians of mixed ethnic origin. The results were based on blood samples withdrawn at 4-hour intervals during a 24-hour span (in March 1978) from 20 subjects from Fukuoka (average age 20.4 +/- 0.1 years) and 16 subjects from Minneapolis (average age 20.2 +/- 0.4 years). The rhythms in the two populations showed similarities in some characteristics and differences in others. The timing of high values, i.e., of acrophases, objectively assessed by curve-fitting (and of corresponding 95 per cent confidence limits) was at 07(36) (05(00), 10(16) and 06(32) (03(00), 10(00) for Japan and USA, respectively. As objective measures of the extent of predictable rhythmic change mean amplitudes, in nanograms per milliliter per hour (ng/ml/hour), were similar (0.31 and 0.32); a statistically significant difference (P less than 0.05) was found in mean amplitudes expressed as percentage of the rhythm-adjusted average. Mean rhythm-adjusted average values (mesors) were lower in women from Japan than in those from the United States: (1.64 +/- 0.14 and 2.39 +/- 0.23 ng/ml/hour, respectively; P less than 0.01). A statistically significant difference in dietary salt, indicated by differences between the Japanese and North American women in the urinary excretion of sodium and chloride (P less than 0.05), almost certainly contributed to these results.

Adolescent↗
PubMed1980

Kinetics and biotransformation of lormetazepam. II. Radioimmunologic determinations in plasma and urine of young and elderly subjects: first-pass effect.

A specific and sensitive radioimmunoassay has been developed for a new benzodiazepine, lormetazepam. After intravenous injection, lormetazepam levels in plasma fell in three (alpha, beta, gamma) dispositional phases, two of them (alpha, beta) mainly reflecting different distribution processes. The terminal (gamma) phase correlated well with the rate of renal elimination of glucuronides. Oral doses were completely absorbed with widely varying absorption half-lifes (t1/2s) amounting to an average of 0.67 +/- 0.53 hr. Dose-dependent maximum plasma levels were reached in about 2 hr. Lormetazepam undergoes first-pass metabolism of about 20% of an oral dose. Total clearance was in the range of 200 ml/min. There was a trend toward slower terminal disposition phase in elderly subjects. In younger subjects, the terminal phase t1/2 was about 10 hr. Lormetazepam glucuronide peak plasma levels were reached by about 6 hr. Thereafter, the level fell in one (elimination) phase, with a t1/2 of 12 hr in young subjects and with a significantly (p < 0.05) different t1/2 of about 20 hr in the elderly. Renal clearance was calculated as about 30 to 40 ml and did not show an age-dependent difference. Recovery of lormetazepam glucuronide with urine amounted to 70% to 80% of the dose during 72 hr after intravenous injection in both age groups.

Adult↗
PubMed1980

Pharmacokinetics and pharmacodynamics of mepindolol sulphate.

Five clinically healthy, male volunteers were each given an intravenous dose of 1.19 mg of 2-methyl-14C-mepindolol sulphate, followed one week later by an oral dose of 20 mg. In addition, the effect of mepindolol sulphate was studied in 3 male test subjects after repeated oral administration for 8 days with a daily dose of 2 x 2.5 mg using the heart rate behaviour model during submaximum ergometer exercise. Synchronously with pharmacodynamics, pharmacokinetic data were also obtained after multiple dosing.

Administration, Oral↗
PubMed1980

Diflucortolone valerate (Nerisona): a comparative vasoconstriction test in artificially induced hyperemia of the skin.

In 20 healthy volunteers of both sexes the vasoconstrictive activity of diflucortolone valerate in two of its commercially available formulations (water-in-oil emulsion and pure fat base) was compared with that of four other substances: fluocinonide; betamethasone-17,21-dipropionate; hydrocortisone-17-butyrate; and clobetasol-17-propionate in corresponding galenical formulations. The visual assessment of vasoconstrictive activity after 10 hours revealed a statistically significant superiority of diflucortolone valerate in its fat base over the corresponding galenical formulations of fluocinonide, clobetasol-17-propionate, and hydrocortisone-17-butyrate. Diflucortolone valerate in a water-in-oil emulsion was statistically better after eight hours than the cream formulations of fluocinonide; clobetasol-17-propionate, and betamethasone-17,21-dipropionate.

Administration, Topical↗
PubMed1979

The pharmacokinetics and biotransformation of the new benzodiazepine lormetazepam in humans. I. Absorption, distribution, elimination and metabolism of lormetazepam-5-14C.

The pharmacokinetics and metabolism of the new benzodiazepine lormetazepam were investigated in five male volunteers using the 14C-labelled drug (position 5). Lormetazepam was administered intravenously and orally, at a dose of 0.2 and 2 mg respectively, to each of the test subjects. Measurements of total radioactivity showed that the drug was absorbed completely and eliminated almost exclusively by the renal route. Maximum plasma level of active ingredient and total radioactivity were observed about 2 hours and 5 hours following oral administration. As early as 30 min following oral administration, concentration of active ingredient amounted to 80% of the maximum values. After both treatments the terminal half-life of total radioactivity and lormetazepam glucuronide in plasma corresponded to the half-life of elimination in urine of about 13 hours. After enzymatic hydrolysis with beta-glucuronidase/arylsulphatase, an average of 90% of total radioactivity from various urine and plasma samples was extractable with ether. Extracts from plasma contained only unchanged drug, indicating free and conjugated lormetazepam as ingredients of total radioactivity. Extracts from urine could be separated into lormetazepam and its N-demethylation derivative lorazepam. The relative amount of excreted lorazepam conjugate was demonstrated to be time-dependent, probably due to enterohepatic circulation. Since less than 6% of the total dose was demethylated by both routes of administration, it can be assumed that lormetazepam is the active product.

Absorption↗
PubMed1979

Investigations of pharmacokinetics of ethinyloestradiol to specific consideration of a possible first-pass effect in women.

Ethinyloestradiol-3H was given intravenously and orally to four and three women, respectively, in a dose of 60 micrograms and 3 mg. To another three female volunteers, 100 micrograms of ethinyloestradiol was administered by both routes in succession. Drug concentration in plasma and total radioactivity in plasma, urine and faeces were measured for different periods of time. Intraindividual comparison of the area under the drug level vs. time curve after intravenous and oral administration of 100 micrograms showed that ethinyloestradiol is subject to an about 60% first-pass effect in women. The time course of ethinyloestradiol concentration in plasma can be described by a 3-compartment model after intravenous injection and by a 2-compartment model after oral administration, because an early disposition phase with a half-life of about 15 minutes only becomes visible after i.v. injection. On an average, the terminal half-life of unchanged ethinyloestradiol level and total radioactivity was calculated to be about 1 day. However, a high variability was found with this parameter as well as with the rate and degree of elimination in urine.

Absorption↗