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Biomedical subjects

J Valenta

Publications and source records attributed to J Valenta.

At least 55 records · Page 3Linked to original sources
PubMed1988

Isolation and structure determination of Pachybasium cerebrosides which potentiate the antifungal activity of aculeacin.

A set of four cerebrosides was isolated from a Pachybasium species and purified by preparative reversed-phase HPLC. All four products displayed activity in a natural product screen aimed at detecting novel cell wall-active antifungal agents based on synergy with the known glucan synthetase inhibitor, aculeacin. Based on degradation studies, fast atom bombardment mass spectrometry and 13C and high field 1H NMR techniques, the structure of the major cerebroside was determined to be (4E,8E)-N-D-2'-hydroxy-(E)-3'- hexadecenoyl-1-O-beta-D-glucopyranosyl-9-methyl-4,8-sphingadiene. The other components were found to be the corresponding 2'-hydroxypalmitic acid analog with one less double bond and an analogous pair containing 2'-hydroxystearic acid with and without the 3' double bond.

Antifungal Agents↗
PubMed1986

Spontaneous renal allograft rupture. Clinical and pathological patterns.

Rupture of an allografted kidney occurred in five patients 5-17 days after transplantation. In one patient the microscopic pathological changes corresponded with the nodose polyarteritis pattern. In four patients interstitial rejection nephritis with severe haemorrhage and haematoma was found. It is suggested that the bleeding is due to peristatic hyperaemia and defects in the inner elastic membranes. In one case multifocal necrotizing arteriopathy was the main pathogenetic factor.

Adult↗
PubMed1984

Anti-Candida activity of polyoxin: example of peptide transport in yeasts.

The polyoxins, nucleoside peptide antibiotics, are effective inhibitors of chitin synthesis in some fungi and yeasts. Although isolated chitin synthetases appear to be equally sensitive to inhibition by polyoxins, intact yeast cells are relatively insensitive. It has been suggested that polyoxins enter cells by a peptide carrier transport mechanism. In this paper, we report results which demonstrate that changes in the growth conditions significantly affect the degree of sensitivity of Canidida albicans to the polyoxins. For example, a minimal inhibitory concentration of 0.1 micrograms/ml was obtained in a defined medium compared with a minimal inhibitory concentration of 1,000 micrograms/ml with conventional media. Various noninhibitory di- and tripeptides, when added to the media, were found to antagonize the anti-Candida activity of polyoxins. In addition, polyoxin-resistant mutants of C. albicans were shown to exhibit cross-resistance with other dipeptide antibiotics. The data reported herein support peptide transport of polyoxins in C. albicans.

Antifungal Agents↗