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Biomedical subjects

S Pfeifer

Publications and source records attributed to S Pfeifer.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Biotransformation and pharmacokinetics of AWD 26-06, 8-chloro- 5,10-dihydro-5-[bis(2-hydroxyethyl)aminoacetyl]-11H-dibenzo[b,c] [1,4]diazepin-11-one hydrochloride, in the rat].

Following p.o. and i.v. application of the 14C-labelled AWD 26-06 (6 mg/kg b.w.) with anticholinergic activity, blood levels (-24 h) and excretion (urine, feces-72 h; bile-7 h) were studied in Wistar rats. Intestinal absorption amounted to 30% of the dose administered in water solution. Elimination half-lives in blood were 0.6 h and (after Cmax 3-4 h p.a.) 8 h. Excretion was mainly by feces (unchanged drug and biliary excreted metabolites) and to less extent by urine.

Animals↗
PubMed1990

[Biotransformation of the trapidil (rocornal) derivative AR 12463 in the rat].

After p.o. administration of 5-piperidino-7-[N-pentyl-N-(beta- hydroxyethyl)]amino-s-triazolo[1,5-a]pyrimidine (1; AR 12463) more than 15 metabolites were isolated from urine and feces of male Wistar rats. Only small amounts of unchanged 1 were observed. The structure of 12 metabolites was elucidated or proposed on the basis of UV-, 13C NMR- and mass spectra. Main metabolites are 5-piperidin-4'-olyl-7-[N-pentyl-N-(beta- hydroxyethyl)]amino-s-triazolo[1,5-a]pyrimidine and 5-piperidin-4'-olyl-7-[N-pent-4-olyl-N-(beta-hydroxyet hyl)]amino-s- triazolo[1,5-a]pyrimidine. The other metabolites are mainly hydroxy- or ketopentyl derivatives and piperidinoles or piperidinones, respectively. Conjugates of most of the metabolites were identified, but the ratio phase-I/II metabolites was about 3:1. In contrast to trapidil, 5-methyl-7-diethylamino-s- triazolo[1,5-a]pyrimidine, no hydroxy derivatives of the bicyclic system were observed. The major part of unchanged 1 and metabolites is excreted via kidneys.

Adsorption↗
PubMed1990

[Biotransformation and excretion of N,N'-bis(3-(2-ethoxyphenoxy)-2-hydroxypropyl)ethylenediamine dihydrochloride (Falirytmin) in rats].

Falirytmin (1) was metabolized in rats almost completely. Besides small amounts of 1 in urine and feces 18 metabolites could be separated. The proposed structures of 14 compounds demonstrate aromatic hydroxylation, N- and O-dealkylation, side-chain oxidation, alcohol dehydrogenation and N-acetylation. The main route of excretion of 1 and metabolites was with the feces. After p.o. or i.v. administration of 14C-O-ethyl-1 the average excretion of radioactivity in urine, feces and expired air was about 75% in 96 h. The residual activity in organs was about 2-2.5%. Whole-body autoradiography confirms these results. Only slight 14C-activity was seen in muscle, fat, liver, bone marrow and gut.

Animals↗
PubMed1990

[Possibilities of cognitive behavior therapy in general practice].

Cognitive behavior therapy has achieved an important standing among the various approaches in psychotherapy. The article gives a short overview over the history of cognitive behavior therapy and delineates its applications in psychotherapy, especially in the treatment of mild to moderate depressions. Further indications include the treatment of anxiety disorders, as well as in the skills training and self-management of schizophrenic patients. Therapeutic experience underscores the importance of a multimodal concept, embedded in a trusting therapeutic relationship. Cognitive behavior therapy must not be viewed as mere therapeutic technique but rather as a therapeutic attitude with the goal of helping the patient achieve better self-efficacy.

Cognitive Behavioral Therapy↗
PubMed1990

[Cytokine release in sarcoid alveolitis].

In sarcoidosis a compartmentalized activation of the immune system exists which yields clinical parameters of disease activity. By means of the spontaneous interleukin-1 and tumor-necrosis-factor-alpha release the same phenomenon could be demonstrated for the macrophage/monocyte system.

Acute Disease↗
PubMed1989

[Biotransformation of phenolglycosides leiocarposide and salicin].

Leiocarposide (1; 3-beta-D-glucopyranosyloxy-2-methoxy-6-hydroxy-benzoic acid -2'-beta-D-glucopyranosyloxybenzyl ester) is a phenolic glycoside from Solidago virgaurea L. After oral administration to rats it will be only poorly absorbed and mostly unchanged fecaly excreted. In the urine were found less than 10% as metabolites: leiocarpic acid (3; 3,6-dihydroxy-2-methoxy-benzoic acid, 2% of the administered dose), 3-conjugates (2%), salicylic acid (5; 0.5%), 5-conjugates (0.1%) and salicyluric acid (6; 0.5%). On the other hand salicin (2), structural part of 1, is good absorbed. In the urine were excreted 15% of the unchanged drug and the following metabolites: 0.1% saligenin (4), 30% 5, 5% 5-conjugates, 0.1% 6, 2% gentisic acid (7) and 0.1% 2,3-dihydroxy-benzoic acid (8). The different metabolic rates are explicable by the high stability of the ester bond of 1. It is hydrolyzed in artificial intestinal fluid only very slowly (t1/2 = 41.7 h).

Animals↗
PubMed1989

[Biotransformation of pyridazines. 1. Pyridazine and 3-methylpyridazine].

Pyridazin (1) and 3-methylpyridazine (6) undergo oxidative biotransformation in an unexpected high degree. Beside the unchanged compounds, after administration of 1 two isomeric monohydroxylated products (2, 3), 4,5-dihydrodihydroxypyridazine (4) and 4,5-dihydroxypyridazine (5) and after administration of 6 one ringhydroxylated 6-derivative (7), 3-hydroxymethylpyridazine (8), one ringhydroxylated 3-hydroxymethylpyridazine derivative (9) and 4,5-dihydroxy-3-methylpyridazine (10) were suggested as urinary metabolites in rats. 2 and 7 are the main metabolites of 1 and 6, respectively.

Animals↗
PubMed1989

[The biotransformation of leiocarposide and salicin phenol glycosides--examples for special consideration of the absorption and metabolism of glycosidic compounds].

After parenteral administration of leiocarposide (1, 3-beta-D-glucopyranosyloxy-2-methoxy-6-hydroxybenzoic acid-2'-beta-D-glucopyranosyloxybenzylester) and salicin to the rat the glycosides were mostly excreted unchanged in urine. In contrast to the oral administration (see [1]) only small amounts of metabolites [1: 0.2% of the dose as leiocarpic acid and 0.1% salicylic acid; 2: 0.05% 5] were observed. By in vitro experiments could be shown, that the hydrolysis of ester and glycosidic bonds from 1 to 3 and saligenin and from 2 to 4 took place microbially mostly in the cecum and colon of the rats. The reactions are also visible in the homogenate of kidney. Präparations of liver, lung and serum showed no activity. 4 in the homogenates of liver, kidney and lung, in the gut-wall and the serum was oxidized to 5. The further product of oxidation of 5, gentisic acid, arise only in liver homogenate.

Animals↗
PubMed1989

[Biotransformation of 5-phenyl-1,3,4-benzotriazepines].

After administration of three 2-aminosubstituted 5-phenyl-1,3,4-benzotriazepines with hypoglycemic effects to rats 10 metabolites were isolated from urine and feces besides traces of the unchanged drugs. N-Dealkylation, aromatic hydroxylation, N-acetylation and ring contraction by hydrolytic processes beginning in the stomach occurred. The main excretion route is with the feces.

Animals↗
PubMed1988

HLA and red blood group antigens in pregnancy disorders.

Total of 356 women with various types of pregnancy disorders as well as their husbands were classified in four groups regarding the type of the disorder as follows: 1. Recurrent spontaneous abortions (RSA) of unknown etiology (N = 105) and RSA - primary aborters only (N = 84); 2. Blighted ovum (N = 80); 3. Rh immunization in pregnancy (N = 90); 4. ABO immunization in pregnancy (N = 47). Two groups of couples were used as controls: 1. Couples randomly taken from forensic medicine cases of paternity evaluation (N = 104); 2. Couples having two or more children with HLA immunization in pregnancy (N = 78). The couples from all groups were typed for red blood group antigens of ABO, Rhesus, MNSs, Kell, Duffy, Lewis, Kidd and P systems and also for HLA antigens. Significantly higher frequency of antigen HLA-A9 was found in women with RSA (corr. p = 0.0003) and in women with pregnancy disorders caused by Rh immunization (corr. p = 0.0136). In couples with RSA the degree of HLA compatibility was significant (p = 0.0048) and the reactivity of spouses in MLR was significantly decreased (p = 0.0001). Significantly, more low responders in MLR were also found among the women with RSA as compared to the controls (p = 0.0217). Two possible pathologic mechanisms may explain the association between HLA antigens and RSA: 1. immunological defects which are linked to HLA-D/DR region causing malfunction of immunosuppressive mechanisms during pregnancy; 2. endocrinological defect which is linked to HLA region as 21-OH hydroxylase deficiency gene.

Female↗
PubMed1988

[Triperiden (Norakin): biotransformation in vivo and in vitro].

After oral application of triperiden (1; Norakin) to male Wistar rats besides the unchanged isomers of 1 (1a and 1b, respectively [3]) six hydroxy metabolites and an artifact were isolated from urine and also identified in faeces. All metabolites are hydroxy derivatives of the piperidine and the tricyclic moieties of the molecule 1a. No hydroxylation of the phenyl ring was observed. 10-20% of the metabolites were sulfate and/or glucuronide conjugates. Main metabolites were 2 and 3 (greater than 50% of the total excretion products). About 70% of 1a, 1b and metabolites were excreted with the urine. The in vivo metabolites also could be identified in the 9000 g supernatant of rat and human liver homogenates.

Animals↗
PubMed1988

[Triperidin (Norakin): separation, stability and structure of stereoisomers].

The antiparkinsonian triperiden (1; as hydrochloride Norakin) is a mixture of the stereoisomers 1a and 1b. Their identification and separation by chromatographic methods or fractional crystallisation of the tartrates is described. By means of IR- und 13C-NMR spectral data structures of 1a and 1b are proposed. Under proton catalysis 1b racemizes to 1a. In acidic solution (heating in 0.1 mol.1-1 HCl or storage in gastric juice at 37 degrees C) hydrolysis of 1 takes place and four isomeric products were observed (Z1-Z4), which arise by cleavage of the cyclopropyl moiety. The main product Z2 was identified as the 2"-hydroxy derivative. The solid drug is stable at least for 5 years.

Antiparkinson Agents↗
PubMed1986

[In vitro and in vivo photochemical reactivity of methaqualone-1-oxide].

Methaqualone-1-oxide (1) exhibits photochemical reactivity. By irradiation of 1 with solar light the oxaziridin 3 is formed at first, which reacts in vitro (human proteins) and in vivo (rats) with macromolecules. As result of the photochemical in vitro and in vivo reactions of 1 the photoproduct 2-acetamidobenzoic acid-2'-methylanilide (6), involved in oxidation of protic compounds, was detected and after hydrolysis of proteins it appears that the short-lived 3 was adding to proteins.

Animals↗
PubMed1986

[In vitro and in vivo photochemical reactivity of quinine- and quinidine-N-oxide].

By irradiation with UV-light quinine- and quinidine-1,1'-dioxide in polar solvents are rearranged to 2'-oxo derivatives and in nonpolar solvents to formylindol derivatives. Rats being exposed to UV-light after oral administration of quinine- or quinidine-1,1'-dioxide showed in blood plasma the 2'-oxo derivates too. In accordance with the results of the different fotochemical reactivity of quinoline-1-oxide-, chlordiazepoxide, methaqualone-1-oxide and some pyrido-pyrimidine-8-oxides a first drafting is developed due to the supposed toxic effects of the exited imino-N-oxides.

Animals↗