PubMed Health⌕ Search

Biomedical subjects

E Frankus

Publications and source records attributed to E Frankus.

At least 19 recordsLinked to original sources
PubMed1998

Pharmacokinetics of tramadol and bioavailability of enteral tramadol formulations. 2nd communication: drops with ethanol.

The pharmacokinetics and the absolute bioavailability of tramadol hydrochloride (CAS 36282-47-0) after oral administration of Tramal drops (with ethanol) were determined in a balanced cross-over study in 8 (4 male and 4 female) volunteers in comparison with the intravenous injection. Each fasting volunteer received two single doses of 100 mg tramadol-HCl, one by oral (1 ml of drops) and one by intravenous route (2 ml of a solution for injection). The formulations were administered in the morning; the washout period was one week. Serum and urine concentrations of tramadol-HCl were determined by gas chromatography-mass spectrometry and gas chromatography, respectively, and the pharmacokinetic evaluation was carried out model-dependently. Only the extent of bioavailability and the renal clearance were calculated model-independently. The extent of the absolute bioavailability (F) of tramadol after oral administration of the drops, based on AUC data, was 66.3% (point estimate; n = 8) with a 95% confidence interval of 58.1-75.6% (ANOVAlog). The areas under the serum concentration curves of tramadol-HCl calculated by curve fitting (AUC), which agreed very well with the model-independently determined areas (AUC), were 2390 +/- 712 h.ng/ml (p.o.) and 3490 +/- 510 h.ng/ml (i.v.) (mean +/- SD; n = 8). After oral administration the means of the serum concentration peaks were 308 +/- 89 ng/ml (cmax) and 1.20 +/- 0.39 h (tmax), the half-life of absorption was 0.34 +/- 0.18 h (t1/2,ka) and the lag time 0.23 +/- 0.01 h (t0). The biological half-life in the terminal phase (t1/2,beta) was 5.5 +/- 0.9 h and agreed well with the value of 5.2 +/- 0.8 h determined after i.v. injection. There were large differences between the volunteers in the distribution rate. For the slower distribution half-life (t1/2,alpha) mean values of 1.2 +/- 0.7 h (p.o.; n = 6) and 1.9 +/- 0.7 h (i.v.; n = 6) were obtained. The values determined after i.v. injection for the total distribution volume and the total and renal clearance were 216 +/- 21 l (Vd,beta), 487 +/- 71 ml/min (Cltot) and 77 +/- 20 ml/min (Clren), respectively. These results show that after administration of the drops (with ethanol) the active ingredient tramadol is rapidly absorbed and that the extent of the absolute bioavailability is about the same as after oral administration of tramadol capsules.

Administration, Oral↗
PubMed1996

Thalidomide derivatives and the immune system. 6. Effects of two derivatives with no obvious teratogenic potency on the pattern of integrins and other surface receptors on blood cells of marmosets.

The two thalidomide (Thd) derivatives beta-EM12 and phthalimidophthalimide (Phtpht), which exhibit no obvious teratogenicity, were tested for their ability to induce changes in the pattern of lymphocyte subpopulations, and especially changes in integrin receptors, in marmosets (Callithrix jacchus). Previously, Thd and its highly teratogenic derivative alpha-EM12 had been found to alter the expression of adhesion molecules, such as CD2 (LFA-2) or CD11a/CD18 (LFA-1). None of these typical effects on adhesion receptors were observed following administration of the relatively high daily doses of 50 mg/kg body wt beta-EM12 and Phtpht. Nevertheless, there were some minor effects, such as alterations in the receptor density on peripheral blood mononuclear cells, which were often contrary to the effects induced by Thd. Mainly affected were: CD8 cells, B cells bearing the CD54 receptor and CD4 cells bearing the CD56 (NCAM) surface marker. We observed an increase in the receptor density of CD11c (p150,95) on monocytes with Phtpht but not with beta-EM12. The inability of the two substances with no obvious teratogenic potential to typically modify beta 2-integrin receptors on white blood cells at comparatively high doses is consistent with our hypothesis, that the teratogenicity of Thd may also be linked to alterations in the expression of adhesion molecules.

Animals↗
PubMed1994

Embryotoxic effects of thalidomide derivatives in the non-human primate Callithrix jacchus. 5. Lack of teratogenic effects of phthalimidophthalmide.

The teratogenic potency of the thalidomide (Thd) derivative phthalimidophthalimide (Phtpht) was assessed in the common marmoset (Callithrix jacchus), by oral administration of the relatively high daily dose of 50 mg Phtpht/kg body wt, during the susceptible period (days 48-61 of pregnancy). Since in this species daily doses of only 100 micrograms/kg body wt of the Thd derivative EM12 already induce typical gross structural abnormalities in nearly 100% of the fetuses, investigations with a small number of these New World monkeys allow a rough estimation of the teratogenic potency of Thd-type substances. Macroscopic inspection and skeletal evaluation of ten fetuses gave no indication of dysmorphogenesis following treatment with Phtpht. We conclude that Phtpht has little, if any, Thd-type teratogenic potency in this non-human primate.

Animals↗
PubMed1985

Chemical, enzymological and pharmacological equivalence of urokinases isolated from genetically transformed bacteria and human urine.

Low molecular weight urokinase (LUK), which was prepared from E. coli containing a plasmid coding for human pro-urokinase, has an amino acid sequence identical to that of LUK isolated from human urine (uLUK) but lacks the carbohydrate side chain at Asn 144 of the B chain. This chemical difference results in an altered mobility in SDS polyacrylamide gel electrophoresis and an apparently increased specific activity of the E. coli-derived product (cLUK) in diffusion-limited test systems (fibrin agar plate tests). Comparative enzymological investigations in homogeneous phases reveal that the active centers and the substrate recognition sites of cLUK and uLUK are congruent. No significant difference between the enzymes was detectable in the following parameters: Michaelis constants and maximum velocities with the synthetic substrate S-2444; activation rates of human and porcine plasminogen; specificity for ten chromogenic substrates; inhibition constants for the competitive inhibitor benzamidine; inhibition by placental urokinase inhibitor and polyclonal antibodies. Further, cLUK and uLUK dissolved fibrin clots prepared from human plasma in vitro with essentially identical velocities. Both, cLUK and uLUK efficiently lysed injected emboli in rabbits and prevented renal fibrin deposition and death due to endotoxin infusion in rats. It is concluded that cLUK, despite the lack of the carbohydrate side chain, is functionally identical and pharmacologically equivalent to uLUK.

Amino Acid Sequence↗
PubMed1983

Designing prostacyclin analogues.

A series of prostacyclin analogues were synthesized and investigated for influence on blood pressure in rats, in vivo inhibition of platelet aggregation in rats, and in vitro inhibition of platelet aggregation in human platelet-rich plasma. The common feature of the analogues described is a replacement of C1-C4 of prostacyclin by a carboxyphenylene residue. The following structure-activity relationships were obtained. Only the meta-carboxyphenylene derivatives yield substantial prostacyclin activity. The 2,3,4-trinor-1,5-inter-m-phenylene prostacyclin analogues in contrast to the natural prototype are reasonably stable against hydrolysis of the enolether bond. The corresponding 2,3,4-trinor-1,5-inter-m-phenylene analogues of carbaprostacyclin have a somewhat lower specific activity but are superior in stability at acid pH values. With regard to the stereoisomerism at the delta 5 double bond, the Z-isomers of the oxa-cyclic prostacyclin series and the E-isomers of the carba-cyclic prostacyclin series are substantially more active than their counterparts. As with natural prostacyclin, the OH group at C15 has to be present in S-configuration. The "wrong" isomers do not inhibit prostacyclin-dependent effects. Resistance against 15-hydroxyprostaglandin dehydrogenase is achieved by substitutions at or near C15. Optimum specific activity combined with resistance against all known prostaglandin-activating enzymes is observed in prostacyclin and carbaprostacyclin analogues, in which the terminal n-pentyl residue is replaced by cyclohexyl. Duration of action, i.e. lowering of blood pressure in anaesthesized rats and inhibition of platelet aggregation in anaesthesized rats, was investigated with selected analogues in order to check the consequences of chemical and metabolic stabilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1982

Comparison of standard immunosuppression with adjuvant antilymphoblast globulin in primary cadaver kidney transplant survival.

Adjuvant, prophylactic, antilymphoblast globulin and standard immunosuppression have produced comparable long-term cadaver kidney graft survivals at separate institutions. A comparison was made of 35 primary cadaver kidney grafts into recipients treated with prophylactic, adjuvant antilymphoblast globulin to 55 recipients of primary cadaver kidney grafts treated with standard immunosuppression. Antilymphoblast globulin delayed early rejection episodes (P under 0.05), making early post-transplant management simpler. There were no significant differences between the two groups with respect to graft losses due to rejection at any interval beyond one month.

Antilymphocyte Serum↗
PubMed1982

The complete amino acid sequence of low molecular mass urokinase from human urine.

The sequence of all 253 amino acids of the heavy (B-) chain of human urinary urokinase was determined. The fragmentation strategy employed included cyanogen bromide cleavage of S-carboxymethylated B-chain at Met and/or Trp residues, cleavage of acid-labile Asp-Pro bonds, and the use of the specific endoproteinases Lys-C and Arg-C for generation of overlapping fragments. For sequence determination automated solid- or liquid-phase techniques of Edman degradation were used. The amino acid sequence obtained substantiates the serine protease character of the B-chain of urokinase: a considerable homology with other serine proteinases, especially with the B-chain of human plasmin, was proved. The pertinent active site amino acids were localized: His-46, Asp-97, and Ser-198. A carbohydrate side chain, containing at least 4 glucosamine and 2 galactosamine residues, was demonstrated to be fixed at asparagine in position 144. The sequence data presented, together with the sequence of the second (A1-) chain of low molecular mass urokinase which was reported by us in an earlier communication, complete the knowledge of the whole primary structure of an active form of human urinary urokinase.

Amino Acid Sequence↗
PubMed1982

The primary structure of high molecular mass urokinase from human urine. The complete amino acid sequence of the A chain.

The complete sequence of 157 amino acids of the light (A) chain of high molecular mass urokinase from human urine was determined. The fragmentation strategy included cyanogen bromide cleavage of the S-carboxymethylated A chain at the methionine and/or tryptophan residues and use of the specific endoproteinase Lys-C. For sequence determination automated solid- or liquid-phase techniques of Edman degradation were used. C-terminal amino acids of the A chain were determined by consecutive treatment with carboxypeptidase A and B. The amino acid sequence obtained revealed a significant homology to peptide chains of other serine proteinases. Accordingly, the sequence of the A chain can be divided into three domains: 1) The growth factor domain with homologies to murine epidermal growth factor and a particular sequence of bovine clotting factor X, 2) The "kringle" domain with homologies to "kringle" structures, e.g. in plasminogen, and 3) the connecting peptide domain containing the A1 chain of low molecular mass urokinase. Together with the amino acid sequence of the B chain, which was presented by us in an earlier communication, the sequence data presented complete the primary structure of high molecular mass urokinase from human urine.

Amino Acid Sequence↗
PubMed1982

The metabolic fate of supidimide in the rat.

The absorption, metabolism and excretion of 3-(2,3-dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-2-oxopiperidine (supidimide) in the rat are investigated. Following oral administration of 35S-labelled supidimide (12.5 and 25 mg/kg), the radioactivity is rapidly absorbed and excreted almost quantitatively within 72 h. 85% of the radioactivity administered is recovered from urine. In the faeces a further 14% is found predominantly resulting from biliary excretion. Excretion rates of urinary radioactivity show a 2-phase course with half-lives of 2.6 h and 10 h. Unchanged supidimide is eliminated with a half-life of 2.1 h. A total of 10 metabolites are identified in urine, faeces or in vitro systems and quantified. Identification of the metabolites is achieved by co-crystallization or co-chromatography with synthetic reference compounds, chemical analysis, mass spectrometry or combinations of these techniques. The pattern of metabolites observed in vivo and in vitro studies reveal that supidimide is primarily oxidized in the piperidone moiety of the molecule by the microsomal drug metabolizing system. Largely spontaneous hydrolysis of preexisting or newly formed carbonamide bonds gives rise to the variety of metabolic products. Hydrolysis of the sulfonamide bond and oxidation of the benzene moiety are not detectable. Only after subchronic treatment with an elevated dosage of supidimide (greater than or equal to 150 mg/kg) is a reversible induction of cytochrome P-450 observed.

Animals↗
PubMed1981

Comparative teratological investigation of compounds structurally and pharmacologically related to thalidomide.

Compounds differing from thalidomide in either the phthalimide or the 2,6-dioxopiperidine moiety of the molecule were synthetized and tested for teratogenic potency in White New Zealand rabbits. Both the 2,6-dioxopiperidine and 2-oxopiperidine derivatives of phthalimide and phthalimidine were found to be highly teratogenic. A somewhat higher teratogenic potential appeared to be associated with the 2,6-dioxopiperidine derivatives. The most potent teratogen investigated was clearly 3-(1,3-dihydro-1-oxo2H-isoindol-2-yl)-2,6-dioxopiperidine (EM12). Compounds in which the phthalimide ring was replaced by 2,3-dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol, did not induce any embryopathic effect differing from control data. No consistent correlation between teratogenic activity and sedative properties of the compounds was detected. The results are discussed in respect to current views of the molecular mechanism leading to thalidomide embryopathy.

Animals↗
PubMed1981

[Biotransformation of tramadol in man and animal (author's transl)].

Following p.o. administration of 14C-labelled rac.-1-(e)-(m-methoxyphenyl)-2-(e)-dimethylaminomethyl-cyclohexan-1-(a)-ol hydrochloride (tramadol hydrochloride, CG 315, Tramal) to mice, hamsters, rats, guinea pigs, rabbits, dogs and man the metabolic pathways were investigated and the results compared. After synthesis of the reference substances the metabolites were identified by co-chromatography using both TLC (thin-layer chromatography) and HPLC (high-performance liquid chromatography) methods, by co-crystallization and by gas chromatography-mass spectrometry. In all species the main metabolic pathways are N- and O-demethylation (phase I reactions) and conjugation of O-demethylated compounds (phase II reactions). 11 metabolites are known, 5 arising by phase I reactions (M1 to M5) and 6 by phase II reactions (glucuronides and sulfates of M1, M4 and M5). The 5 phase I metabolites are mono-O-demethyl-tramadol (M1), mono-N-demethyl-tramadol (M2), di-N-demethyl-tramadol (M3), tri-N,O-demethyl-tramadol (M4) and di-N,O-demethyl-tramadol (M5). The biotransformation scheme of tramadol is qualitatively identical in man, dog, rabbit, guinea pig, rat, hamster and mouse. In all species M1 and M1-conjugates, M5 and M5-conjugates and M2 are the main metabolites, whereas M3, M4 and M4-conjugates were only formed in minor quantities. Following p.o. administration to man and animals 14C-tramadol are rapidly and almost completely absorbed. The unchanged drug and metabolites are mainly excreted via kidneys. The cumulative renal excretion of total radioactivity accounts for approximately 90% in man and varies from 86 to 100% in mouse, hamster, rat, guinea pig, rabbit and dog; the residual of the applied radioactivity appears in the feces. Apparently tramadol is metabolized much more rapidly in animals than in man. For that reason there are appreciable differences between man and animals in the amount of tramadol excreted unchanged in the urine (about 30% and 1% of the p.o. dose, respectively). After incubation with beta-glucuronidase and arylsulfatase at least 81% of the excreted radioactivity could be extracted from the urine of man animals (with the exception of the guinea pig and the rabbit). In man all extractable metabolites were identified.

Animals↗
PubMed1978

[Studies on chemical structure and analgetic activity of phenyl substituted aminomethylcyclohexanoles (author's transl)].

Phenyl substituted aminomethylcycloalkanole derivatives were synthetized and tested for analgetic activity. Substances with a high ratio between acute toxicity and analgetic efficacy were selected for further investigations. Structure-activity relationships of this group were evaluated and compared with those of morphine and morphine-like 4-phenylpiperidino derivatives. The basic structural requirement for the new compounds is a cycloalkane ring with a phenyl group and a dimethylaminomethyl residue in ortho-position. The analgetic activity is improved if the aromatic ring is substituted with an oxygen containing group in meta-position. In contrast to classical narcotic analgesics the analgetic efficacy is not lost in derivatives bearing a hydrogen substituent at the central carbon atom.

Analgesics↗
PubMed1978

[On separation of isomeres, structural elucidation and pharmacological characterization of 1-(m-methoxyphenyl)-2-(dimethylaminomethyl)-cyclohexan-1-ol (author's transl)].

1-(m-Methoxyphenyl)-2-(dimethylaminomethyl)-cyclohexan-1-ol (L 201) was split into the cis- and trans-isomers and the conformations of the two isomers were determined by 13C-NMR-spectroscopy. Molecule models showed that both conformeres were similar to the geometrical structure of morphine. The adaptation of the morphine structure was better with the more active trans-isomer than with the cis-isomer. Tramadol, the trans-isomer, was separated into its optical antipodes. When tested for analgesia in the electro-stimulation test with mice, all compounds showed analgetic activity. The trans-isomer was more active than the cis-isomer and the (+)-form of the trans-isomer was more active than the (--)-form. Given by s.c. route, the (+)-transisomer E 382 was 1/3 as active as morphine. However, the Straub-tail reaction and the withdrawal jumping tests yielded more favourable results with L 201 and tramadol than with E 382.

Analgesics↗