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Biomedical subjects

B Bannwarth

Publications and source records attributed to B Bannwarth.

At least 109 records · Page 6Linked to original sources

Pharmacokinetics of famotidine in patients with cirrhosis and ascites.

The pharmacokinetics of famotidine has been investigated in ascitic cirrhotic patients. 10 decompensated cirrhotic patients were studied (9m, 1f), who had normal renal function, and six healthy control subjects (4m, 2f), matched for age, sex and weight. Each subject received on two occasions, at least four days apart, a single oral (40 mg) or intravenous dose (20 mg) of famotidine, at 21.00 h in a randomised manner. Serial blood samples were collected and famotidine in plasma was determined by a HPLC/UV method. Plasma data were subjected to non compartmental pharmacokinetic analysis. There were no statistically significant differences in pharmacokinetic parameters between the two groups after either the intravenous or oral administration of famotidine. The findings suggest that the dose of famotidine may not require any adjustment in ascitic patients without renal failure.

Administration, Oral↗

Effect of age on the disposition of sodium fluoride.

Sodium fluoride (NaF) is used in the treatment of axial osteoporosis and so is mostly given to old patients. Since its pharmacokinetics has not been studied in the elderly, the pharmacokinetics of an enteric-coated tablet containing 50 mg NaF has been investigated in 15 aged inpatients (aged 65 to 75 y) and 12 young healthy volunteers (aged 21 to 26 y). The serum AUC of fluoride was 1.7-time higher in older than in younger subjects. There was a strong inverse correlation between the AUC and either body surface area (BSA) or glomerular filtration rate (GFR), both of which were very much lower in the elderly. This concluded that if efficacy or safety are related to the bioavailability of fluoride, it may be valuable to adjust the dosage of fluoride accordingly to the GFR and BSA.

Adult↗

Plasma and cerebrospinal fluid concentrations of paracetamol after a single intravenous dose of propacetamol.

Since the antipyretic and probably the analgesic effects of paracetamol are, at least in part, centrally mediated, its plasma and cerebrospinal fluid (CSF) concentrations were measured in 43 patients with nerve-root compression pain. Each subject was given a short i.v. infusion of 2 g propacetamol, a prodrug which is hydrolysed to paracetamol within 7 min. Single blood and CSF samples were drawn concomitantly in each patient at intervals between 20 min and 12 h. Maximum CSF drug concentrations were observed at the 4th hour, subsequent concentrations exceeding those in plasma. The elimination half-life of paracetamol calculated from pooled data was shorter in plasma (2.4 h) than in CSF (3.2 h). The time-course of paracetamol in CSF may parallel that of analgesic effect.

Acetaminophen↗

[Mode of action of non-narcotic analgesics].

According to Lim's experiments, non-narcotic analgesics are usually considered as "peripherally" acting drugs. Conversely, most of these compounds were shown to easily cross the blood-brain barrier, and hence partly produce their effects by a central mechanism. The relative contribution of each site of action may vary from one drug to another. Aspirin-like drugs may act by inhibiting arachidonate cyclooxygenase in both the damaged tissues and the central nervous system. Finally, these drugs appear to be either selective, or dose-dependent, or nonspecific inhibitors of prostaglandin-synthetases.

Analgesics↗

Protein binding of indomethacin in human cerebrospinal fluid.

The binding of the non-steroidal anti-inflammatory drug indomethacin to proteins in human cerebrospinal fluid (CSF), drawn during lumbar puncture from 10 patients affected by lumbosciatica, was measured by equilibrium dialysis and spectrofluorimetry. Similar binding studies on human serum albumin solutions (0.5 and 1 g/L) were performed using the same techniques. The mean binding percentage of indomethacin determined by equilibrium dialysis was 40%. The results obtained by both techniques allowed us to conclude that the binding of indomethacin in CSF was essentially due to albumin.

Dialysis↗

Determination of 2-mercaptopropionylglycine and its metabolite, 2-mercaptopropionic acid, in plasma by ion-pair reversed-phase high-performance liquid chromatography with post-column derivatization.

A simple and fast high-performance liquid chromatographic method was developed for the simultaneous measurement of 2-mercaptopropionylglycine (Tiopronine) and its metabolite (2-mercaptopropionic acid) in human plasma after the administration of a pharmaceutical dosage form (Acadione). The sample treatment before high-performance liquid chromatographic analysis consisted of the reduction of the corresponding disulphides by tri-n-butylphosphine and protein precipitation with ethanol. Separation was achieved by ion-pair high-performance liquid chromatography on a reversed-phase column (LiChrospher RP 18e) with cetrimonium bromide as counter ion and detection by fluorimetry after post-column derivatization with a selective thiol reagent, i.e. pyrenemaleimide. The high frequency of the analyzed samples and validation results make the method suitable for pharmacokinetic studies, and this was demonstrated by the first results obtained after the administration of an oral dose of 500 mg of Tiopronine to two healthy subjects.

Chemical Precipitation↗

Auto-immune spondylodiscitis associated with collagen induced arthritis in rats: high field MRI findings.

The spinal involvement of the tail was studied in Wistar Furth rats immunized with bovine native type II collagen. Focal caudal autoimmune spondylodiscitis occurred 5 weeks after sensitization, as assessed histopathologically. High field Magnetic Resonance Imaging (MRI) was useful in depicting these caudal abnormalities that were related to juxta-diskal enthesitis. The occurrence of such inflammatory enthesopathies could serve as an experimental approach for physiopathological and therapeutical studies of spondylarthropathies.

Animals↗

Influence of muramyl dipeptide on established experimental arthritis in rats.

The effects of MDP, a potent inducer of cytokines, were studied in four batches of Wistar Furth rats with established experimental arthritis. Arthritic rats were given a daily sc injection of 10, 100, 200 or 400 micrograms MDP respectively. Muramyl dipeptide increased the severity of clinical events in a dose-dependent manner, with the exception of the 10 micrograms dose which was ineffective. The levels of anti-collagen antibodies were not however significantly enhanced by MDP. Radiological lesions and histological changes were maximal at high dosage regimens. Paradoxically, the acute phase reactive alpha 1 glycoprotein was little affected by MDP treatment.

Acetylmuramyl-Alanyl-Isoglutamine↗

Lack of adjuvanticity of human recombinant interleukin-1 beta in collagen induced arthritis in rats.

We investigated the influence of human recombinant interleukin-1 beta (hrIL-1 beta) on the time-course of collagen induced arthritis (CIA) when injected concomitantly with the arthritogenic emulsion. Three sensitizing procedures were compared. The control group received type II collagen only. The other groups differed by the adjunction of demonstrated (MDP) or potential (IL-1 beta) adjuvant. No adjuvant effect of IL-1 was observed as judged on clinical or radiological scores. On the contrary, MDP significantly worsened the lesions of the injected right hindpaw, and increased the incidence of CIA. Surprisingly, humoral response to type II collagen was decreased in the group receiving IL-1 beta. This might be explained by a non specific increase of antigen clearance.

Acetylmuramyl-Alanyl-Isoglutamine↗

Tenoxicam concentrations in synovium and joint cartilage in humans.

Tenoxicam is an NSAID of the oxicam group. Its distribution in articular tissues was investigated in 12 patients who required total arthroplasty of the hip. They were given tenoxicam 20 mg once daily for 8 to 30 days before surgery. Blood, synovium and cartilage samples were taken concurrently during surgery, about 14 hours after the last tenoxicam dose. The tissues were ground using a freeze grinder. Tenoxicam was assayed by HPLC. Tenoxicam concentrations averaged 6.21 +/- 3.81 micrograms/ml in plasma, 7.56 +/- 4.67 micrograms/g in synovium and 2.05 +/- 1.43 micrograms/g in cartilage. The individual synovium/cartilage ratios ranged from 1.9 to 9.7. Finally tenoxicam exhibited more affinity for its target organ (synovial tissue) than for joint cartilage.

Adult↗