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Biomedical subjects

J Pabst

Publications and source records attributed to J Pabst.

At least 19 recordsLinked to original sources
PubMed1991

[Serological studies of the recent infections of Austrian horses with the equine arteritis virus].

944 serum samples of horses, collected in 1988 and 1989, were examined for the occurrence of antibodies against equine arteritis virus by a microneutralizations test. In 10.9% of all sera reactors could be found. The distribution of seropositive horses varied from 4.6% (Salzburg) to 15.7% (Lower Austria). From Tyrol and Vorarlberg no samples could be obtained. It was not possible, to correlate clinical symptoms (infertility, respiratory symptoms, fever and edema) with the infection. It is assumed, that the disease appears in Austria only in a clinical inapparent form.

Animals↗
PubMed1989

Digitoxin in patients with hepatorenal insufficiency after repeated oral administration.

Following chronic oral administration of digitoxin 0.1 mg day-1 the pharmacokinetics of this glycoside were studied in seven patients with hepatorenal insufficiency and were compared with those of seven healthy volunteers. Liver cirrhosis of the patients was confirmed by liver biopsy. Mean creatinine clearance of the healthy subjects was 129.7 +/- 3.3 ml min-1 (mean +/- SEM), that of the patients was 25.6 +/- 20.4 ml min-1. Mean antipyrine clearance (parameter of oxidative liver function) was 49.7 +/- 6.0 ml min-1 in the volunteers and 22.0 +/- 2.9 ml min-1 in the patients. Plasma protein binding of digitoxin (PPB) was 95.0 +/- 1.1% in the patients and 96.7 +/- 0.6% in the healthy subjects (n.s.). Total body clearance of digitoxin (Cltot) was 0.0728 +/- 0.0120 ml min-1 kg-1 in the patients and 0.0615 +/- 0.0027 ml min-1 kg-1 in normals (n.s.]. Mean steady state plasma levels (Css) of the patients were 18.3 +/- 4.7 ng ml-1 and 15.8 +/- 1.3 ng ml-1 in the normals (n.s.). Our data obtained from chronic oral administration do not indicate a reduced total body clearance of digitoxin in patients with hepatorenal insufficiency.

Administration, Oral↗
PubMed1987

Pharmacokinetics of bisoprolol during repeated oral administration to healthy volunteers and patients with kidney or liver disease.

The pharmacokinetics of bisoprolol were investigated following oral administration of 10mg once daily for 7 days in 8 healthy subjects, in 14 patients with different degrees of renal impairment and in 18 patients with liver disease. In healthy subjects peak and trough steady-state concentrations of 52 micrograms/L and 11 micrograms/L, respectively, an elimination half-life of 10.0 hours and total body clearance of 14.2 L/h were observed. 5.21 mg/24 hours of unchanged bisoprolol were recovered following urinary excretion during the dosage interval. In 11 patients with renal impairment (mean CLCR = 28 +/- 5 ml/min/1.72m2) half-life was prolonged to 18.5 hours, and peak and trough concentrations were 74 and 32 micrograms/L, respectively. Correspondingly, urinary excretion decreased to 3.35 mg/24 hours and total body clearance to 7.8 L/h. In uraemic patients (CLCR less than 5 ml/min/1.73m2) the total clearance of bisoprolol was 5.0 L/h and the elimination half-life was 24.2 hours. In patients with liver cirrhosis half-life increased to 13.5 hours, steady-state peak and trough concentrations increased to 62 and 22 micrograms/L, respectively, and total body clearance decreased to 10.8 L/h. The present study indicates that in patients with impairment of kidney or liver function accumulation of bisoprolol above a factor of 2 did not occur. However, in the terminal stages of insufficiency of kidney or liver function bisoprolol dosage should not exceed 10mg.

Adrenergic beta-Antagonists↗
PubMed1986

Interaction of bisoprolol with cimetidine and rifampicin.

In 6 healthy volunteers the pharmacokinetics of bisoprolol under steady-state conditions was investigated over three consecutive phases: over 7 days of 10 mg of bisoprolol once daily per os, 7 days of 10 mg of bisoprolol once daily plus 400 mg of cimetidine t.i.d. and 14 days of 10 mg of bisoprolol and 600 mg of rifampicin once daily with adequate intervals free of medication. After therapy with bisoprolol alone peak plasma levels (Cssmax) of the beta-blocker were 55.5 +/- 6.4 ng/ml (means +/- SEM), area under the plasma level-time curve (AUC tau) was 597 +/- 70 ng/ml.h, total body clearance (CL) 15.8 +/- 1.8 l/h and elimination half-lives (t1/2 beta) 10.1 +/- 1.2 h. Cimetidine did not cause any significant changes in the pharmacokinetics of bisoprolol. Co-administration of rifampicin resulted in a decrease in Cssmax (43.0 +/- 6.9 ng/ml), AUC tau (397 +/- 54 ng/ml X h) and t1/2 beta (6.2 +/- 0.4 h). Accordingly, total body clearance increased to 23.8 +/- 2.5 l/h (p less than 0.05). In conclusion bisoprolol showed a statistically significant but probably clinically not important interaction with the enzyme-inducing drug rifampicin, but not with the enzyme inhibitor cimetidine.

Adrenergic beta-Antagonists↗
PubMed1986

Bioavailability and elimination of digitoxin in patients with hepatorenal insufficiency.

Following administration of digitoxin, 1 mg intravenously, the pharmacokinetics of this glycoside were studied in eight healthy volunteers and in eight patients with hepatorenal insufficiency (mean creatinine clearance 19.6 +/- 2.9 ml/min; antipyrine clearance 25.6 +/- 3.2 ml/min; means +/- SEM). Liver cirrhosis of the patients was confirmed by liver biopsy. Plasma protein binding of digitoxin (means +/- SEM) was 95.1 +/- 0.7% in the patients and 95.6 +/- 1.2% in the volunteers (NS). Total body clearance of digitoxin was 0.0530 +/- 0.0040 ml/min/kg of body weight in the patients and 0.0547 +/- 0.0043 ml/min/kg of body weight in the healthy subjects (NS). When elimination half-lives of the patients and the volunteers were compared, there was also no significant difference (7.0 +/- 0.77 days in the patient group and 7.8 +/- 0.8 days in the volunteers). Our data concerning digitoxin kinetics in patients with hepatorenal insufficiency do not indicate an accumulation of the drug in these patients.

Adult↗
PubMed1986

Pharmacokinetics and metabolism of bisoprolol-14C in three animal species and in humans.

The pharmacokinetic properties of bisoprolol-14C were studied in Wistar rats, beagle dogs, and Cynomolgus monkeys. Bisoprolol is well absorbed in these species; independent of the route of administration (i.v. or p.o.), 70-90% of the 14C-dose was recovered in urine. Faecal excretion was approximately 20% in rats and less than 10% in dogs and monkeys. Rats excreted approximately 10% of the dose in bile after i.v. as well as after oral administration. The plasma half-life of the unchanged drug was approximately 1 h in rats, 3 h in monkeys, and 5 h in dogs. The bioavailability was 40-50% in monkeys, approximately 80% in dogs, and 10% in rats. Studies in rats have shown that the drug is rapidly taken up by the tissues. After i.v. administration, high levels of radioactivity were found in lung, kidneys, liver, adrenals, spleen, pancreas, and salivary glands. After oral administration, the highest concentration occurred in the liver and kidneys. With the exception of plasma and liver, unchanged bisoprolol was the major radioactive constituent in all tissues studied. Both the blood-brain and placental barriers were penetrated, but only to a small degree. No accumulation of radioactivity in tissues was observed after repeated dosing (1 mg/kg/day). The metabolism of bisoprolol was studied in the same three animal species and in humans. The major metabolites are the products of O-dealkylation and subsequent oxidation to the corresponding carboxylic acids. The amount of bisoprolol excreted unchanged in the urine is 50-60% of the dose in humans, 30-40% in dogs, and approximately 10% in rats and monkeys.

Absorption↗
PubMed1986

Concentration kinetics of propranolol, bisoprolol, and atenolol in humans assessed with chemical detection and a subtype-selective beta-adrenoceptor assay.

After oral administration of single doses of 240 mg of (+/-)propranolol (prop), 200 mg of (+/-)-atenolol (aten), and 100 mg of (+/-)-bisoprolol (biso) to six healthy male volunteers, the plasma concentration time profile was investigated. To measure total plasma concentrations of the parent racemic mixture of drug administered, a HPLC-assay of drug concentrations was used. To detect active metabolites and stereoselective pharmacokinetics of the racemates, plasma concentrations were also monitored by means of a subtype-selective receptor assay, using a beta 1-adrenoceptor preparation from rat salivary glands. It is shown that relevant amounts of active metabolites do not become apparent for either of the three drugs investigated. Furthermore, for neither of them can significant stereoselective elimination characteristics be seen. Monophasic elimination characteristics with t1/2 of 4.8 +/- 0.42 (prop), 6.87 +/- 0.46 (aten), and 9.19 +/- 0.38 h (biso) become apparent. The maximum concentrations observed after administration of the doses mentioned previously were 220 +/- 71 (prop), 904 +/- 104 (aten), and 445 +/- 32 (biso) (ng/ml plasma). One can conclude from comparison with the results from receptor-binding studies that the 100 mg dose of biso is five- to seven-fold more potent than the 200 mg dose of aten, with respect to antagonism versus beta 1-adrenoceptor-mediated effects.

Adrenergic beta-Antagonists↗
PubMed1986

Pharmacokinetics of bisoprolol and influence on serum thyroid hormones in hyperthyroid patients.

Nine hyperthyroid patients (FT4 greater than or equal to 20 ng/L; FT3 greater than or equal to 6 ng/L) were given 1 X 10 mg bisoprolol/day p.o. for a period of 7 days. Pharmacokinetic data were derived from measurements of plasma bisoprolol concentrations after the first dose and at steady state after 7 days treatment. The thyroid hormones FT4, FT3, and rT3 were determined in the serum before and after bisoprolol treatment. In addition, subjective and objective parameters of thyroid function were recorded during the course of the therapy. The maximum bisoprolol concentrations measured after the first dose and after 7 days were 54.3 +/- 2.1 and 70.3 +/- 3.8 ng/ml, respectively, the minimum concentrations being 9.6 +/- 1.0 ng/ml and 11.9 +/- 1.7 ng/ml, respectively. This yields an accumulation factor of 1.2. At steady state, the plasma elimination half-life of bisoprolol was 9.8 +/- 0.9 h. No significant changes in serum thyroid hormones were observed during bisoprolol treatment. There was, however, an improvement in the subjective and objective clinical symptoms of hyperthyroidism. In comparison with the findings in healthy volunteers, the pharmacokinetics of bisoprolol remained unaltered in mild to moderate hyperthyroid patients. After oral application of bisoprolol, only small variations in the plasma concentration were observed inter- and also intraindividually in the course of treatment. This finding reflects the high absolute bioavailability of bisoprolol.

Adrenergic beta-Antagonists↗
PubMed1986

Pharmacodynamic profile of bisoprolol, a new beta 1-selective adrenoceptor antagonist.

The pharmacodynamic profile of bisoprolol, a new beta 1-selective adrenoceptor antagonist, was investigated in four independent studies including 36 healthy male volunteers. Using the model of exercise-induced tachycardia (ET) the beta-adrenoceptor blocking properties of bisoprolol (2.5-40 mg) were examined in comparison to metoprolol (50 and 100 mg), propranolol (40 and 80 mg) and atenolol (50 and 100 mg). The maximal reduction of ET was achieved between 1 and 4 h following single oral administration. The dose-response relationship using individual maximal reduction of ET showed, on a molar basis, that bisoprolol is about 5, 7 and 10 times more effective than propranolol, atenolol and metoprolol, respectively. In the model of insulin-induced hypoglycaemia bisoprolol behaved as a beta 1-selective adrenoceptor antagonist. There was a good correlation (r = 0.94) between the log bisoprolol concentration and the reduction in exercise-induced tachycardia. Bisoprolol is a potent new cardioselective beta-adrenoceptor antagonist with a competitive action at beta 1-adrenoceptors.

Adrenergic beta-Antagonists↗
PubMed1982

Digitoxin accumulation.

1 Nine healthy volunteers received single 1 mg intravenous doses of digitoxin, following which serum digitoxin concentrations were measured at multiple points in time over the next 14 days. 2 Mean kinetic variables for digitoxin were: volume of distribution, 0.76 l/kg; elimination half-life, 8 days; total clearance, 0.049 ml min-1 kg-1. 3 After a drug-free interval of at least 4 months, subjects took 0.07 mg of oral digitoxin daily for 28 consecutive days. Serum digitoxin concentrations were measured during the period of dosage and in the 21 day post-dosage washout. 4 Digitoxin accumulation was slow, proceeding with a mean half-life (7.9 days) that was nearly identical to the single-dose half-life. However, the two were not significantly correlated. 5 Mean observed steady-state serum concentrations (15.4 ng/ml) also were nearly identical to those predicted from the single-dose study (15.3 ng/ml), but again the two were not significantly correlated. 6 Steady state is very slowly attained after initiation of maintenance therapy with digitoxin. The kinetic data suggest that a loading dose on the average should be 12 times the maintenance dose.

Adult↗
PubMed1981

Fluproquazone in the management of strains and sprains.

A double-blind randomized trial was carried out in 59 patient suffering from moderately severe to severe strains and sprains to compare the efficacy of 4-(p-fluorophenyl)-1-isopropyl-7-methyl-2(1H)-quinazolinone (fluproquazone) in the relief of pain. Patients received either 50 mg or 100 mg fluproquazone up to 6 times daily for 3 days. The results of subjective assessments showed that after 2 days pain had either completely resolved or markedly improved in all patients. Both treatments were equally effective in relieving both spontaneous pain and pain on movement after 1 and 2 days. No differences were found between the two groups in the patients' overall evaluation of treatment or physicians' assessment of therapeutic response. Both dosage were well tolerated during the short-term trial.

Adult↗
PubMed1979

Clinical pharmacology phase I of cefazedone, a new cephalosporin, in healthy volunteers. II. Pharmacokinetics in comparison with cefazolin.

In two consecutive cross-over studies, each involving 10 healthy volunteers, the pharmacokinetics of (6R,7R)-7-(2-[3,5-dichloro-4-oxo-1(4H)-pyridyl]-acetamindo)-3-([(5-methyl-1,3,4-thiadiazol-2-yl)-thio]methyl)-8-oxo-5-thia-1-azabicyclo[4,2,0]oct-2-ene-2-carboxylic acid (cefazedone, Refosporen) in comparison with cefazolin were investigated after single i.v. and i.m. administration. The doses were: i.v. cefazedone 500 mg and 1000 mg; cefazolin 1000 mg; i.m. cefazedone 500 mg, cefazolin 500 mg. The pharmacokinetic parameters were analysed by applying an open two-compartment model. The pharmacokinetics of cefazedone are nearly identical with those of cefazolin. In particular, it must be noted that cefazedone has a relatively long serum elimination half-life (1.64 +/- 0.23 h after i.v. and 1.85 +/- 0.51 h after i.m. administration) and that cefazedone exhibits, in comparison with cefazolin, a more favourable concentration ratio of central vs. peripheral (= tissue) compartment (1:2).

Adult↗