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Biomedical subjects

K Albrecht

Publications and source records attributed to K Albrecht.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Multicenter study of the results of the extraction of transvenously implanted heart-pacemaker electrodes using continuous traction].

The continuous traction of firmly grown-in collar electrodes from the right ventricle is a simple technique poor in complications with a high success rate, which can be recommended taking into consideration the indications in the failure of the immediate manual extraction and which can be performed in every centre for cardiac pacemakers. Apart from the consideration of adequate informations in literature this evidence above all depends on the evaluation of data of 29 cases from 10 centres for cardiac pacemakers.

Adult↗
PubMed1982

Transformation of 12-deoxycardenolids with Streptomyces purpurascens.

Streptomyces purpurascens transforms primary and secondary 12-deoxycardenolids into digoxin, 7 beta-hydroxy-digitoxin and 7 beta-hydroxy-digoxin, respectively. A metabolic pathway is proposed for cardenolid transformations and the enzymes participating in it are investigated. The substrate concentration in the medium can be increased by using a water-miscible solvent of electron donor character. The newly developed procedure yields 0.5 g/1(-1) of digoxin in a five-day fermentation.

Amidohydrolases↗
PubMed1981

[Stereotactic operations-complications and the legal position (author's transl)].

Postoperative complications like lethality and morbidity and are the decisive aspects in the controversy about the acceptance of stereotactic operations, especially in cases of deviant sexual behaviour. The mere fact that there is a favourable efficiency-risk quotient promotes the danger of an uncritical expansion to non-conformists and scientific outsiders, of an uncontrolled manipulation, and an imminent intrusion by extramedical controlling instances into the relations between physician and patient. Stereotactic operations do not fall under the castration law because of their aim and their effect to harmonize an extremely disturbed sexual behaviour. Since the personality structure is not destroyed by this intervention, the operation is not immoral and consequently not penal. Nevertheless, it is justified only as a method of last resort to patients who are therapy-resistent, self-destructive, and aggressive towards others.

Female↗
PubMed1981

7 beta -hydroxycardenolide glycosides.

The microbial transformation of digitoxin (I) by Streptomyces sp. yielded digoxin (III) as main product along with the by-products 7beta -hydroxydigitoxin (II) and 7beta -hydroxydigoxin (IV). The present paper is concerned with the structure elucidation of 7beta-hydroxycardenolides as well as with the formation of some of their derivatives.

Biotransformation↗
PubMed1975

Microbiological degradation of diazepam.

In studying the transformation of diazepam (7-chloro-1-methyl-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one) by fungi isolated from soil. N1-demethylation and cleavage of the diazepine ring were observed. Three metabolites: 7-chloro-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, 2-acetamido-2"-benzoyl-4"-chloroacetanilide and 2-acetamido-2"-benzoyl-4"-chloro-N-methylacetanilide were isolated and identified.

Acetanilides↗
PubMed1975

Microbiological hydroxylation of norethisterone.

Hydroxylation of norethisterone by a large number of fungi has been investigated. 1alpha-Hydroxy-, 6beta-hydroxy-, 10beta-hydroxy-, 10beta,11beta-dihydroxy-15alpha-and 15beta-hydroxy-derivatives were formed from norethisterone. The microbiological dehydrogenation of 10beta-hydroxy-norethisterone resulting in 10beta,17beta-dihydroxy-17-ethynyl-1,4-estradien-3-one was also observed. The structure of transformation products was established by chemical and spectroscopical methods.

Chemical Phenomena↗
PubMedDate not supplied

Preparation of thiomer microparticles and in vitro evaluation of parameters influencing their mucoadhesive properties.

It was the aim of this study to develop mucoadhesive microparticulate delivery systems based on thiomers and to investigate parameters influencing their mucoadhesive properties. Microparticles were prepared via coazervation of thiolated or unmodified polycarbophil with fluorescein-diacetate as marker. The protective effect of the polymers toward enzymatic hydrolysis by intestinal enzymes was investigated. Mucoadhesion studies with microparticles, applied in dry and prehydrated form, were performed by ascertaining their residence time on intestinal mucosa. Furthermore, the influence of the amount of thiol groups on mucoadhesion was studied in vitro. Results showed that in comparison to unmodified polycarbophil, thiolated polycarbophil provided a more than 3-fold higher protective effect for the incorporated marker fluorescein-diacetate toward hydrolysis. When being applied in dry form 23.4 +/- 4.8% of the fluorescence marker being embedded in thiomer microparticles remained adhering to the intestinal mucosa within 3 h. In contrast, only 11.6 +/- 2.0% of the marker remained on the mucosa, when the thiomer microparticles were applied in prehydrated form. In addition, tests performed to assess the impact of the amount of thiol groups pointed out that a high amount of thiol groups is advantageous in order to further improve mucoadhesive properties. This knowledge should contribute to the design of highly efficient drug delivery systems being based on thiomer microparticles.

Acrylic Resins↗