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Biomedical subjects

U Wenzel

Publications and source records attributed to U Wenzel.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Pressure-course events in the tabletting of phenylbutazone].

The distribution to different compression phases via formation of the 1. derivation of the increased force curve is elucidated by the example of the phenylbutazone (2. AB-DDR) compression by means of an instrumented, slow-motion (1 r. p. m.) excentric press, equipped with piezoelectric force recorders and semiconductor transducers articulated to the upper stamp. In the case of phenylbutazone it is subdivided into at least three sections.

Chemical Phenomena↗
PubMed1984

[The effect of dehydration loss of tablet excipients on the energy- distance diagram and on tablet characteristics].

Four tabletting agents of the micro-crystalline cellulose type (Heweten 10, Heweten 12, Heweten 40 and Avicel PH 101) as well as a potato starch lactose granulate had been tabletted on an instrumented slow-motion eccentric press (1 r. p. m.) following storage at different relative humidities. The data resulting from force-punch displacement measurements had been related to the radial steadiness to breakage and the dehydration loss of the relevant agent.

Cellulose↗
PubMed1982

Pharmacological activities of a homologous series of pyrazole derivatives including quantitative structure-activity relationships (QSAR).

In a series of fourteen 1-benzoyl-3-methyl-pyrazole derivatives the antiinflammatory activity in the carrageenin edema of the rat paw was found to be in the potency range of that of aminophenazone. This holds also true of the analgesic, anticonvulsive, and anticholinergic activity of the compounds whereas antihistaminergic activity was 10-fold better and acute toxicity was less than that of aminophenazone. Using the MASCA model as a multivariate method in QSAR the regression matrix of the derivatives substituted in p-position of the benzoyl moiety has been calculated. According to that, all of the biological activities are mainly described in terms of pi, sigma, xi, and L. The increase of inflammatory activity could be expected by substitution of electro-positive substituents of short length (L) and little relative surface tension (xi). Concomitantly, analgesic and anticonvulsive activities could increase whereas anticholinergic and antihistaminergic activities are expected to decrease. The HANSCH analysis is surely to be preferred in investigations of the relationship between physicochemical parameters of compounds and a certain biological activity evoked by them. However, the multivariate MASCA model could be of some advantage in the optimization of chemical structure against the whole profile of biological activities in a series of compounds. Some problems of the MASCA model are briefly discussed.

Analgesics↗
PubMed1982

Structure-activity relationship in nonsteroidal antiinflammatory agents, including QSAR in fenamate derivatives.

First, it is shown that it is not yet possible to outline a generally valid receptor model for the non-steroidal anti-inflammatory agents. This is demonstrated by three examples of receptor models, namely by the model according to Shen, by the receptor concept of Appleton and Brown, and by the concept concerning chelate complex formation between NSA and heme iron of the cyclooxygenase complex according to Peterson et al. This means that the "custom-made" synthesis of NSA with, perhaps, quantitatively and qualitatively better properties is not yet possible. On the basis of this statement, QSAR investigations may be justified in order to optimize known NSA. In this paper, QSAR calculations on 21 fenamate derivatives are reported. For this, both the multivariate and the univariate Hansch Analysis were used. Altogether, 16 approaches to QSAR has been performed using 1 - 4 biological and 3 - 19 physico-chemical parameters, respectively, with 7 - 21 objects. In all cases a dominating influence of pi has been indicated. Other physico-chemical parameters seemed to be of less importance, e. g., sigma, Es, log xi MR, MV, parachor, and Verloop's steric constants. Possible new fenamate structures of higher biological activity are briefly discussed.

Animals↗
PubMed1979

[Pharmacokinetic studies of the propolis constituent pinocembrin in the rat (author's transl)].

The present investigation into the pharmacokinetic behaviour of the propolis constituent pinocembrin which produces a relatively good antimicrobial effect in vitro, points to possible causes of its therapeutical failure when mice infected with Candida albicans were used as a model. The biological half-life periods for the phases of invasion and elimination were 26 and 268 min, respectively. The biological availability was 25%. Almost 15% of pinocembrin are excreted unchanged in faeces and urine. Even in case of oral application of doses of up to 500 mg/kg, the serum pinocembrin concentrations did not equal the MIC (minimal inhibitor concentration) values required in vitro. A considerable first-pass effect and accelerated processes of elimination are discussed as possible causes. It appears from the present findings that pinocembrin may be utilizable only for the external treatment of stomatomycoses.

Animals↗
PubMed1978

Intelligence of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, their parents and unaffected siblings.

IQ measurements were performed in 33 patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (110.6 +/- 13.9), in 29 unaffected siblings (113.8 +/- 11.3) and in 48 parents (104.4 +/- 9.4). The results were significantly higher than normal in the patients and siblings, but not in the parents. They were also significantly higher in the patients and siblings as compared to the parents. It is concluded that neither pre- or postnatal androgen exposure nor a genetic linkage can be made responsible for the increased IQ in congenital adrenal hyperplasia, but that more likely methodological factors (such as outdated standards) account for the higher values in patients and siblings.

Adolescent↗
PubMed1976

[Kleine-Levin syndrome. Female cases and catamneses].

The Kleine-Levin syndrome (periodic hypersomnia and megaphagia in adolescence) was considered till 1962 to be a disorder limited to the male adolescents. Since 1924, however, a few female cases have been reported about. These, being approximately 20 patients, are registered by their essential symptoms together with 2 additional cases observed by the author. Moreover, prospective catamneses, covering periods of more than 12 years, were described for the first time. Probably, the Kleine-Levin-syndrome is the product of disturbed functions involving structures of hypothalamus and the reticular system. The syndrome seems to belong to the same groups of periodical diseases as migraine: in particular it exhibits similar relations to the genital cycle. Therapeutical success was attained by administration of amphetamines. In course of time, the episodes become spontaneously rarer and mostly cease.

Adolescent↗
PubMed1976

[Studies of Nocardia pellegrino SN 5108 pigment mutants: reasons for differences in pigmentation (author's transl)].

Yellow and white mutants of the strains Nocardia pellegrino SN 5108 R have been isolated. Regarding their morphological and physiological properties, the mutants are identical with the wild type bacteria with the exception of their pigmentation and lipid composition. However, the pigment composition (number, Rf-values and spectra of the pigment components) of the yellow mutant is identical with that of the wild type; as a consequence, the modified pigmentation of the yellow mutant cannot be explained by an altered pigment synthesis. The wild type cells and the mutant SN 5108 G contain three main pigment components designated as I, II and III. Components II and III posses a marked indicator character and show a bathochromic shift in solutions of pH 12 or higher. Components II and III contain functional groups which are able to react with acetic acid yielding acetylated products; after acetylating, no bathochromic shift in alkali occurs. Intact cells of the wild type retain their orange-red pigmentation in buffer solution with a pH-value of 12 or higher. Cells of the yellow mutant, however, change the yellow color immediately after the alkali treatment to orange-red; this new color is identical with that of the wild type and can be changed to yellow by placing the cells into 1 N HCl. Regarding these facts it seems to be very probable that the functional groups of the pigment components II and III are differently bound in the wild type and mutant cells. In the mutant, they are accessible to OH- ions yielding a bathochromic shift while in the wild type cells, OH- ions are unable to provoke this shift. It seems to be also probable that different lipids in the two strains are responsible for the binding of the pigments. So far known, this is the first observation about the occurence of pigment mutants with an altered pigment binding site in the cells.

Binding Sites↗