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Biomedical subjects

G Franke

Publications and source records attributed to G Franke.

At least 55 records · Page 3Linked to original sources
PubMed1992

Bioavailability of metronidazole formulations (Vagimid).

The bioavailability of metronidazole (0.5 g) from Vagimid tablets and dragées were compared with tablets of a reference formulation in 12 male healthy volunteers (age 20-32 years, body weight 61-77 kg). Metronidazole and its two main oxidized metabolites in serum were determined quantitatively with an hplc method. Metronidazole from Vagimid tablets was absorbed more rapidly than from the reference but at the same extent of absorption. The pharmacokinetic profile of Vagimid dragées was similar to the behaviour of the reference but AUC of dragées was slightly but significantly lower. All elimination parameters of metronidazole as well as the formation of the two metabolites were not different after administration of the oral formulations.

Adult↗
PubMed1991

Drug oxidation and N-acetylation in rats pretreated with subtoxic doses of streptolysin O.

SLO in sublytic doses (100 HU/kg body wt) depressed the hepatic microsomal cytochrome P450 and aminopyrine-N-demethylase but increased significantly the cytosolic N-acetyltransferase after acute and subacute (5 days) pretreatment of male Wistar rats. Aniline hydroxylase was reduced after acute and unchanged after subacute pretreatment. The effects of SLO on the oxidative enzymes and drug N-acetylation might have been caused by the membranal and immunological properties of the toxin.

Aniline Hydroxylase↗
PubMed1991

Immunotherapy of murine visceral leishmaniasis with murine recombinant interferon-gamma and MTP-PE encapsulated in liposomes.

The efficiency of immunotherapy with murine recombinant interferon-gamma (rIFN-gamma) in mouse visceral leishmaniasis caused by Leishmania donovani was examined. To avoid the side effects encountered after the in vivo administration of high dosages of free IFN-gamma, this lymphokine and muramyltripeptide (MTP-PE) were encapsulated into multilamellar liposomes. We established that a combination of 5 X 10(3) U of IFN-gamma and 6 micrograms of MTP-PE, encapsulated in liposomes and given i.v. in C56BL/6 and BALB/c mice activates macrophages from spleen and liver in vivo to kill L. donovani in vitro. Neither empty liposomes nor the same concentration of free IFN-gamma and/or MTP-PE injected i.v. resulted in a leishmanicidal activity of these macrophage populations. For verification of these results in an in vivo infection model, susceptible mice were infected with L. donovani and were treated with IFN-gamma and MTP-PE encapsulated in multilamellar vesicles. Treatment consisted of multiple i.v. injections beginning 4 and 2 days before infection (prophylactic), either simultaneously with the infection or at various times of the exacerbation and remission phases of visceral leishmaniasis. These mouse strains treated with IFN-gamma and MTP-PE in liposomes had significantly fewer splenic parasites than untreated mice or control animals treated with free drugs or empty liposomes. The targetting of multilamellar vesicles to liver and spleen make them particularly suited for the delivery of macrophage-activating substances used for treatment of visceral L. donovani infection.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1991

N-acetylation and debrisoquine hydroxylation polymorphisms in patients with Gilbert's syndrome.

1. N-acetylation and debrisoquine hydroxylation phenotypes were determined in 54 patients with Gilbert's syndrome and in 247 (sulphamethazine) and 76 (debrisoquine) non-related healthy volunteers. 2. Forty (74.1%) of the patients and 135 (54.7%) of the healthy volunteers were slow acetylators (chi 2 = 6.87). In the patients, the cumulative urinary excretion of sulphamethazine up to 6 h (Ae(0,6)) was significantly lower. No differences in the frequency of debrisoquine poor metabolizers were observed: Gilbert's syndrome 5/54 (9.3%), healthy volunteers 5/76 (6.6%). The metabolic ratios were similar in both groups as well as the urinary recoveries of debrisoquine and its 4-hydroxy metabolite. 3. Gilbert's syndrome seems to be related in some way to N-acetylation but not to the debrisoquine hydroxylation polymorphism.

Acetylation↗
PubMed1991

N-acetylation and oxidative capacity in aged volunteers determined with sulfamethazine and antipyrine.

The elimination of antipyrine (AP 15 mg/kg) and sulfamethazine (SM 500 mg) was measured in healthy volunteers of rapid and slow acetylator phenotype. Nineteen males were 20-32 years of age, 11 males and 6 females between 62-86 years of age. Apparent volume of distribution of AP was reduced in advanced age independent of the acetylator status of the individuals. Total body clearance was significantly lower and half-time and mean residence time were higher only in slow but not in rapid acetylators. In the elderly of both phenotypes, the acetylation ratios of SM were significantly enhanced. Renal and metabolic clearance were decreased and AUC-values of SM and its acetylated metabolite were increased in slow but unchanged in rapid acetylators. Physiological peculiarities of distribution and renal excretion of SM and its acetylated metabolite in advanced age may have caused the contradictory results.

Acetylation↗
PubMed1991

Pharmacokinetics of almitrine in healthy volunteers and patients with essential hypertension.

Pharmacokinetic studies with the arterial chemoreceptor stimulant almitrine (100 mg per os) were performed in 12 healthy volunteers and 8 patients with essential hypertension stage I in order to evaluate the suitability of the drug for physiological tests. The parent compound was determined gas-chromatographically. Almitrine was absorbed with maximal serum levels after 1.8 +/- 0.4 h in healthy volunteers and 1.5 +/- 0.3 h in patients. The elimination proceeded biexponentially with terminal half-lives from 14.6 to 43.4 h in volunteers and 12.5-45.0 h in patients. Further characteristics were large distribution volumes (16.1 +/- 4.5 ml/g in healthy volunteers, 13.9 +/- 4.7 ml/g in patients) and large interindividual variations of all pharmacokinetic parameters by a factor of 2 to 6. Significant differences between healthy individuals and patients were not observed. The drug was well tolerated. The pharmacokinetic properties of almitrine should be included into its evaluation as a test compound.

Administration, Oral↗
PubMed1991

[Serum hyposomolarity, brain edema and the bulbar brain syndrome as complications in the course of severe cranio-cerebral injuries in children].

It is reported on a severe craniocerebral trauma in a child with a rarely occurring spontaneously induced serum hypoosmolality which led to brain edema combined with intracranial increase of pressure and bulbar brain syndrome. By means of bedside brain ventricle catheterization for liquor drainage following drill-hole trepanation, the complication could be controlled. Later the recovery was completed under supervision of the outpatient department. Pathophysiological metabolic peculiarities, especially osmolality, are discussed. The necessity of special and repeated controls of the metabolic characteristics osmolality, sodium and potassium in serum and urine as well as the water and sodium balance within 24 hours is emphasized.

Brain Edema↗
PubMed1990

N-acetylation and debrisoquine type oxidation polymorphism in Caucasians--with reference to age and sex.

Phenotypes of the N-acetylation and debrisoquine type oxidation polymorphism were determined with sulfamethazine and debrisoquine in 145 healthy volunteers (31-80 years, 64 males, 81 females) of a North-East German area. Seventeen (11.7%) were poor metabolizers of debrisoquine and 81 (55.9%) slow acetylators of sulfamethazine. No significant correlations between the frequencies of oxidation and acetylation phenotypes, age, and sex were found. Only a tendency of rapid acetylators to accumulate among individuals above 60 years was noticed. Parameters of phenotyping were not influenced by sex. With age, metabolic ratios of N-acetylation but not of oxidation phenotyping increased. The urinary excretion (0-8 hours) of debrisoquine, sulfamethazine and their metabolites was strikingly reduced in the elderly. Misclassifications of acetylation phenotyping cannot be excluded because of the age dependent kinetics of the test drug.

Acetylation↗
PubMed1990

Oxidation phenotyping with debrisoquine in Germany (East).

An hplc method is described which determines debrisoquine and its metabolite, 4-hydroxydebrisoquine, quantitatively after conversion of the guanidine moieties into the corresponding pyrimidines. Sensitivity, precision, and accuracy have been sufficient enough for the reliable hydroxylation phenotyping of 145 non-related healthy volunteers (64 males, 81 females, 31-80 years). 17 (11%) were poor metabolizers of debrisoquine (gene frequency: 34.2%).

Adult↗
PubMed1990

Tryptophan metabolic studies in patients with presenile cataracts.

In 43 patients with presenile cataracts an oral tryptophan loading test with 5 g L-tryptophan was performed and the 24-hour urinary excretion of kynurenine and xanthurenic acid was determined. 5 cases showed pathological deviations and an excretion pattern of tryptophan metabolites via kynurenine, similar as in vitamin B6-dependent xanthurenic aciduria.

Adolescent↗
PubMed1989

Mouse interferon-gamma in liposomes: pharmacokinetics, organ-distribution, and activation of spleen and liver macrophages in vivo.

Recombinant mouse interferon-gamma (IFN-gamma) was encapsulated into multilamellar vesicles and the proportion of encapsulated IFN-gamma determined by biological activity was 19%. The distribution of 125I-labeled IFN-gamma liposomes in C57BL/6 mice was analyzed. After an initial enrichment of liposomes in lung, more than 60% of total 125I-labeled IFN-gamma was accumulated in spleen and liver. Furthermore, it was observed if the encapsulation of IFN-gamma in liposomes prevented the rapid decay of IFN-gamma in serum of C57BL/6 mice after intravenous injection. We compared the serum decay curve of liposomal and free IFN-gamma, and showed that IFN-gamma encapsulated in liposomes has an elongated availability in the serum. In addition, we established that a combination of 10(2) U/ml IFN-gamma and 1 microgram/ml MTP-PE, encapsulated in liposomes, activates splenic and starch-elicited peritoneal macrophages in vitro synergistically to kill Leishmania donovani promastigotes. After intravenous injection of liposomal IFN-gamma (5 X 10(3) U) and muramyltripeptide (MTP-PE) (6 micrograms) in C57BL/6 mice, splenic and liver macrophages were activated in vivo to kill Leishmania species in vitro. Neither an injection of the same amount of free substances nor injection of empty liposomes resulted in an increased leishmanicidal activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1989

Experiences with a new corneal suction trephine.

The importance of exact trephining for successful keratoplasty is well known. We employ a new suction trephine, thus obtaining exact and sharp cutting margines which are examined by scanning electron microscopy (SEM). The first observed clinical results in 25 cases are good.

Cornea↗
PubMed1989

[The acetylator phenotype in patients with urinary bladder cancer].

In 53 patients suffering from bladder cancer the acelylization phenotype was examined. The frequency of slow acetylizers (70%) was significantly higher than in the control group. The more frequently occurrence of slow acetylizers in the group with professional pollutant exposition is an important reference to a higher bladder cancer morbidity in the case of carcinogen contact. A screening of the acetylization phenotype in professions with carcinogen contact may be important in the prophylaxis of bladder cancer.

Acetylation↗