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A Kowalczyk

Publications and source records attributed to A Kowalczyk.

29 records · Page 2Linked to original sources
PubMed1984

A survey of cutaneous neural lesions for the presence of myelin basic protein. An immunohistochemical study.

The presence of myelin basic protein (MBP) within a skin neoplasm would support its derivation from Schwann's cells, since this substance is routinely present within Schwann's cells in the peripheral nervous system. Using a monoclonal antibody prepared against MBP and an unlabeled antibody peroxidase-antiperoxidase assay, we surveyed a variety of skin lesions suspected of being derived from Schwann's cells to determine whether MBP was present. Myelin basic protein was detected within the cytoplasm of cells composing benign solitary schwannoma (neurilemmoma) and neurofibroma, confirming the association of these lesions with proliferation of Schwann's cells. Myelin basic protein was not found in a variety of intradermal and compound nevus cell nevi nor in malignant melanoma. This negative finding supports electron microscopic evidence suggesting that nevus cells have no relationship to Schwann's cells even though some nevus cell arrangements suggest Schwann's cell derivation under the light microscope.

Animals↗
PubMedDate not supplied

Phenolic acids and depsides from some species of the Erodium genera.

Six natural polyphenolic compounds, brevifolin carboxylic acid, brevifolin, ellagic acid, methyl gallate, gallic acid and protocatechuic acid have been isolated from the methanol extract of the whole plant of Erodium cicutarium (L.) L.'Hérit. (Geraniaceae). Structures were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of these compounds in the other species of the Erodium genera (E. botrys, E. chium, E. ciconium, E. cicutarium, E. glutinosum subsp. dunense, E. gruinum, E. manescavi, E. pelargoniiflorum, E. petraeum) were examined by HPLC with a RP-18 column, and MGD-TLC methods on unmodified silica gel and silica gel chemically modified with polar and nonpolar groups (HPTLC-Si 60 LiChrospher, HPTLC-NH2, HPTLC-DIOL, HPTLC RP-18W).

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Relaxation of water protons in highly concentrated aqueous protein systems studied by 1H NMR spectroscopy.

Concentrated Aqueous Protein Systems, Proton Relaxation Times, Slow Chemical Exchange In this paper we present proton spin-lattice (T1) and spin-spin (T2) relaxation times measured vs. concentration, temperature, pulse interval (tauCPMG) as well as 1H NMR spectral measurements in a wide range of concentrations of bovine serum albumin (BSA) solutions. The anomalous relaxation behaviour of the water protons, similar to that observed in mammalian lenses, was found in the two most concentrated solutions (44% and 46%). The functional dependence of the spin-spin relaxation time vs. tauCPMG pulse interval and the values of the motional activation parameters obtained from the temperature dependencies of spin-lattice relaxation times suggest that the water molecule mobility is reduced in these systems. The slow exchange process on the T2 time scale is proposed to explain the obtained data. The proton spectral measurements support the hypothesis of a slow exchange mechanism in the highest concentrated solutions. From the analysis of the shape of the proton spectra the mean exchange times between bound and bulk water proton groups (tauex) have been estimated for the range of the highest concentrations (30%-46%). The obtained values are of the order of milliseconds assuring that the slow exchange condition is fulfilled in the most concentrated samples.

Animals↗