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Biomedical subjects

W Rupp

Publications and source records attributed to W Rupp.

At least 19 recordsLinked to original sources

[Herpes simplex-associated exacerbation of Crohn's disease. Successful treatment with acyclovir].

Seven years ago, a now 25-year-old man was found to have Crohn's disease of the terminal ileum as well as of the transverse and sigmoid colon. Despite treatment with both corticosteroids and mesalazine the disease progressed and led to almost complete stenosis of the lumen of the sigmoid colon so that surgical intervention was planned. But because immunohistological examination of the small and large intestinal mucosa had demonstrated herpes simplex virus (HSV I + II) DNA, additional treatment with acyclovir appeared worth-while. The morphological and clinical findings indeed changed decisively, obviating surgery. If a virus infection is found to be a pathogenetic co-factor in a case of Crohn's disease, a therapeutic trial with a suitable antiviral agent seems reasonable.

Acyclovir

[Thymus hyperplasia in patients with malignant testicular tumors].

Follow-up serial computed tomographic scans of 124 patients treated for testicular cancer with either radiotherapy or retroperitoneal lymphadenectomy alone or in combination with chemotherapy were evaluated. Thymic enlargement occurred three to 20 months after initiation of treatment in 15 of the 124 patients. Thymic enlargement could histopathologically be demonstrated in seven patients as true hyperplasia. One of these seven patients however had evidence of metastatic disease with thymic infiltration by a malignant teratoma. Thus it may be impossible to distinguish benign thymus hyperplasia from tumor-infiltration on the basis of ct information alone and sternotomy may be required. No severe defect of cellular immunity could be found. There is no specific constellation of lymphocytic markers in peripheral blood which could indicate true thymic hyperplasia.

Adult

Rectal pseudotumor due to Chlamydia trachomatis in a male homosexual.

Chlamydia trachomatis causes a wide spectrum of human genital infections including lymphogranuloma venereum. We describe an unusual case of Chlamydia trachomatis proctitis in a homosexual man presenting with a large, solid tumor in the distal rectum, which was treated successfully by long-term oral doxycycline therapy.

Adult

[Aorto-esophageal fistula in arteria lusoria].

A 29 year old patient with artificial respiration because of a severe trauma was fed by tube. 23 days after his admission to a hospital an uncontrollable bleeding arised out of the oesophagus. The autopsy revealed an aortic-oesophageal fistula, caused by the feeding tube, which owing to the (unrecognised) arteria lusoria had lead to a pressure sore of the oesophagus.

Adult

Penbutolol: pharmacokinetics, effect on exercise tachycardia, and in vitro inhibition of radioligand binding.

The pharmacokinetics of penbutolol 40 mg, its reduction in exercise-induced tachycardia, and the in vitro inhibition of radioligand binding to beta-adrenoceptors by plasma have been investigated in 7 healthy volunteers. The peak penbutolol concentration of 285 ng/ml was observed 1.2 h after administration, and the maximum of 4'-OH-penbutolol of 4.76 ng/ml was found after 1.64 h. Penbutolol was detected for up to 48 h, and 4'-OH-penbutolol dropped below the limit of detection after about 10 h. The terminal plasma concentration of penbutolol declined with an average half-life of 19 h. The maximum reduction in exercise-induced tachycardia was 33 beats/min 2.6 h after taking penbutolol. There was still a significant reduction of about 7 beats/min after 48 h. This effect could be adequately explained by the concentration-time course of penbutolol in combination with Clark's model of the concentration-effect relationship. Antagonist activity in plasma caused 91% inhibition of radioligand binding in vitro to beta 2-adrenoceptors on rat reticulocyte membranes 1.6 h after intake of penbutolol. By 48 h after intake, radioligand binding was still significantly inhibited (23%). The in vitro inhibition of radioligand binding by plasma showed a linear correlation with the reduction in exercise-induced tachycardia for all phases of the workload. The time course of the reduction in heart rate was completely explained by the in vitro inhibition of radioligand binding. However, it was not possible to explain the in vitro inhibition of radioligand binding by the concentration-time course of penbutolol using a simple competition model, although both variables were based on the same sampling site. When the in vitro inhibition of radioligand binding was plotted against the penbutolol concentration at the same sampling times (with both variables transformed to multiples of the apparent inhibition constant) the discrepancy became even more apparent as time-related counterclockwise hysteresis. None of the known metabolites of penbutolol can explain the discrepancy between the penbutolol concentration and the inhibition of radioligand binding in vitro. It appears that an other active metabolite is formed, which contributes to the effect in vitro and in vivo and so can explain the observed discrepancy.

Adrenergic beta-Antagonists

Antitumor activity of imidazolium-bisimidazole-tetrachlororuthenate (III). A representative of a new class of inorganic antitumor agents.

The antitumor activity of imidazolium-bisimidazole-tetrachlororuthenate (III) against the P388 leukemia and against the B16 melanoma was investigated. The test compound showed high activity against these tumor models. The tumor inhibiting effect was in the range or better than the effects of the compounds cyclophosphamide, cisplatin, or 5-fluorouracil, which were tested as positive controls. The effective substance is a new, water soluble, anionic, nitrogen-heterocyclic coordinated, ruthenium species, exhibiting antitumor activity.

Animals

[Galenic and clinico-pharmacologic studies of prednicarbate (Hoe 777)].

The corticoid prednicarbate (test name: Hoe 777) is derived from prednisolone having no halogenic groups (chemical name: prednisolone-17-ethyl carbonate-21-propionate). Because of the specific physical and chemical properties of prednicarbate, galenic research strove to optimize the vehicle. Further development was only performed on those drug-containing bases showing especially good drug release (granting the most favorable action) in a) the vasoconstriction test and b) the UV erythema test practiced on volunteers with healthy skin. Exemplarily dealing with the special preparations predicarbate cream, ointment, and greasy ointment, we give some details of studies on drug dosage, vehicle selection, and the optimum water/lipid ratio.

Administration, Topical

[Effect of forskolin eyedrops on intraocular pressure in healthy males].

Suspensions of Forskolin in concentrations of 0.3; 0.6; and 1.0% decreased effectively the intraocular pressure of healthy subjects when instillated in the conjunctival sac. The suspensions were compared with placebo in double blind studies. The maximum effect was reached 3 hours after application of the 0.3% (22.8%) and 0.6% (27.8%) suspensions and 4 hours after the 1.0% (26.5%) suspension. The higher concentrations decreased the intraocular pressure to the same extent as the lowest concentration but the effect lasted longer: 4 hours after instillation of the 0.3% suspension, 5 hours after instillation of the 0.6% suspension and 7 hours after the 1.0% suspension. The suspensions were well tolerated. Subjective sensations like burning, itching and augmentated lacrimation were observed only in a minor amount and for a short period of time.

Adult

Kinetics of UV-erythema in normal subjects.

In the expanding field of clinical dermatopharmacology we standardized an erythema model for testing drugs with effects on UV-induced inflammation in normal male Caucasian subjects. Using a light source with fibre-optic transmission and precise radiation characteristics, some of the shortcomings of conventional UV-application could be overcome. The radiation geometry during the various experiments was kept constant by a tube, permitting a defined area of exposure. Up to eight skin areas of the backs of normal volunteers were radiated with 86.2% UV-A and 13.8% UV-B. After exclusion of hyporeactive and hyperreactive subjects a good intrasubject reproducibility was obtained repeatedly over at least 3 months. According to the definition of bioavailability, our method allows the measurement of the rate and extent of UV-induced erythema. This model has been used for testing topical steroids, non-steroidal antiphlogistics in a variety of pharmaceutical formulations.

Dose-Response Relationship, Radiation

[Pharmacokinetics and biotransformation of the antimycotic drug ciclopiroxolamine in animals and man after topical and systemic administration].

1. Following the dermal application of the carbon-14 labelled broad spectrum antimycotic 6-cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone, 2-aminoethanol salt (ciclopiroxolamine, Hoe 296, Batrafen) in the form of a 1% aqueous cream to healthy human dorsal skin (penetration time: 6 h; occlusive dressing for 5 h), percutaneous absorption accounted on average for 1.3% of the dose applied. Excretion occurred via the kidney, with biological half-lives of 1.7 h. As can be seen from penetration studies of cadaverous skin, the horny layer contained the highest concentrations, with values of 2300-4500 microgram/cm3. The levels determined in the corium were still above the minimum inhibitory concentrations. These concentrations were already obtained at the first test stage (1.5 h after application) and did not change virtually at all over the longer penetration period. According to studies using histoautoradiography, ciclopirox can penetrate the skin via the epidermis and the hair follicles. When ciclopirox-14C-olamine aqueous cream was spread on the surface of fingernails, the radioactive-labelled compound penetrated right through the nail. The percutaneous absorption in dogs was higher, at 5-15% of the dose, than it was in humans. 2. After vaginal application (1 mg/kg) of ciclopirox-14C-olamine in the form of a 1% aqueous cream to bitches, between 42 and 97% of the dose (depending on the animal) was recovered in the urine and faeces, the remainder having penetrated into the tampon used to close the vagina. 3. Ciclopirox is excreted by dogs and man in the urine, primarily as a glucuronide. In humans another glucuronide with properties similar to those of the original substance was detected. Two conjugated, relatively non-polar metabolites were also present in small amounts. The metabolite patterns after oral and dermal application were similar. The binding of ciclopirox to serum proteins in humans was 96 +/- 2% in a concentration range of 0.01-11.0 microgram/ml. 4. Placental transfer was low in the rats studied. Though there was good absorption by the mother animal, the radioactivity in the foetal tissues was always lower than that of the maternal blood.

Administration, Oral

[Adequate and inadequate trials in "clinical" pharmacology].

Our definition, based on 14 years of practical experience, is as follows: In clinical pharmacology, a procedure is adequate if it can be used in normal subjects in a non-invasive way and if it generates relevant information concerning pharmacotherapy in patients. Six examples are discussed in detail; the variable body weight may cause wide variations, for example, in absorption characteristics; unhomogeneous groups of subjects are likely to lead to poorly reproducible results. Body position and food intake (individual eating habits) may disguise drug effects by creating additional "noise". By titrating the heart rate during work load on the ergometer in order to achieve and maintain a target rate, individual differences in physical fitness and skill can be eliminated. Orthostatic regulation of cardiovascular variables may be impaired without concomitant psychic lability. The latter indicates predisposition to placebo responses, e.g. in studies using the standardized tourniquet pain model and mild analgesics. In normal subjects computer analysis of cerebral biosignals in combination with psychometric and behavioural tests usually gives more reliable information as compared to the patient pretreated with different drugs.

Body Weight

Some aspects of the clinical pharmacology of furosemide.

Earlier data on kinetics and dynamics of furosemide given to normal humans are reviewed and the role of different assay methods for the calculation of kinetic variables is emphasized. Adequate timing of serum samples may help to solve the "tail problem", i.e. the increasing loss of precision in the vicinity of the limit of detection. New aspects are reported from studies with a pellet-dosage form of furosemide. Initial peak diuresis is reduced and the duration of action is prolonged. Clinical results in hypertensive patients are in agreement with the data achieved in normal subjects.

Diuresis

Standardized mental stress in healthy volunteers induced by delayed auditory feedback (DAF).

Using delayed auditory feedback (delay 0.175 s) a standardized form of mental stress was investigated in 8 healthy male volunteers. After a resting period and a period of undelayed reading, the volunteers were exposed for 5 min to the DAF stress. During the DAF period heart rate increased by 10% and systolic and diastolic blood pressure increased by 9% and 18%, respectively. As a measure of acute sympathetic activation, plasma concentrations of norepinephrine and epinephrine rose by 68% and 49%, respectively. The activity od dopamine-beta-hydroxylase in plasma was increased by 25%. From these results it can be concluded that the DAF procedure provides a suitable method for inducing a standardized mental stress in normal subjects, which can be measured as changes in biochemical and cardiovascular variables.

Acoustic Stimulation

Pharmacokinetics of single and multiple doses of clobazam in humans.

1. The pharmacokinetics of clobazam and its biotransformation product N-desmethylclobazam were investigated after single and multiple doses in normal subjects. 2. The relevant physicochemical properties of clobazam were measured and are presented. Different assay methods (radiochemical, fluorimetric and gas chromatographic) were applied and the results correlated. 3. After single doses the pharmacokinetic profile of clobazam includes time to peak levels 1--4 h after dosing, peak levels increasing linearly with the logarithm of dose, and terminal half-lives of about 18 hours. At least 87% of an oral dose is absorbed, as indicated by urinary recovery of labelled material. 4. In multiple-dose studies unchanged clobazam levelled off at minimum steady-state concentrations within one week of dosing. During 28 d of medication N-desmethylclobazam accumulated to near steady-state levels about eight times higher than those of the unchanged compound. 5. No pharmacokinetic interactions were discovered between clobazam and the antidepressant nomifensine.

Anti-Anxiety Agents