Biomedical subjects

H Szydlowska

Publications and source records attributed to H Szydlowska.

At least 19 recordsLinked to original sources

PubMed1978

Membranolytic activity of detergents as studied with cell viability tests.

The membranolytic activity of 12 chosen detergents upon Ehrlich ascites tumour and Chinese hamster lung cells were studied with the fluorescein diacetate and the dye exclusion tests of cell viability. It was found that all these tests give reproducible and concordant results when non-ionic detergents are used but for ionic detergents only the fluorescein diacetate test can be applied. Membranolytic activity of the detergents appeared to be uncorrelated with their capacity of membrane solubilization. Digitonin and aescin, the horse-chestnut saponin, were found to be much more toxic than sodium dodecylsulphate or Triton X-100. When the detergents with aliphatic hydrophobic residues were compared, a cationic detergent cethylmethylammonium bromide (CTAB) was more toxic than non-ionic or anionic detergents. A hydrophobic part of the aescin molecule, that is its aglycone appeared responsible for the membranolytic activity of this saponin. When the lytic activity of the tested detergents for the two tested types of cells was compared it was found that the horse-chestnut saponin substances show different toxicity for various cells. It is suggested that in the future some of the detergents can be applied for detection and quantitative monitoring of species and tissue specific differences in plasma membrane properties of animal cells.

Animals↗

PubMed1977

Reduction of nitro-BT by some components of the chloroform-methanol extract of the grey matter of the rat brain.

An attempt was made to extract the substance present in the nerve fibres of the cerebral cortex and basal ganglia which reduced Nitro-BT in alkaline medium pH 9-5 [4,5]. The investigations were performed on 40 white Wistar rats of both sexes and ca. 200 g of body weight. The brains taken for studies were fixed in Baker's formalin for 1,5 hr, thereafter grinded and homogenized in chloroform-methanol solution supplemented up to 100 ml of final volume after homogenisation. Thus prepared solution was left for 24 hr at 4 degrees C temperature and than centrifuged 2000 g/min. The extract was evaporated and the sediment further investigated. The following fraction were received: 1. fraction soluble in aceton, 2. fraction soluble in ethylalcohol, 3. fraction soluble in ether, 4. fraction soluble in water and 5. the sediment. Each fraction was incubated with a standard medium containing Nitro-BT. After incubation the amount of reduced Nitro-BT in each of the incubation medium was spectrophotometrically measured. The most intense reduction was found in the incubation medium with the water fraction. The spectrophotometrically determined reduction of Nitro-BT of the water fraction compared with that of the gangliosides solution were similar. The addition into the incubation media biogenic amines and N,N-diethyl-p-phenylenediamine enhances the reduction of Nitro-BT significantly. According to the results obtained an interference of gangliosides and of the investigated amines in the reduction of Nitro-BT is suggested.

Animals↗

PubMed1977

Histochemical investigations of thyrosine in normal and pathological glia cells.

Investigations on thyrosine content in normal and pathological glia cells are the continuation of researches on occurrence of protein functional groups in abnormal glia cells (Szydlowska, 1970a, 1970b). The investigations carried out with the use of Caselli, Glenner and Lille methods have shown that fluctuations of thyrosine level in nuclea and cytoplasm of glia cells pathologically changed correspond to quantitative changes of other functional groups of proteins. Hence it may be assumed that the observed increase of thyrosine in pathologically changed glia cells is not connected with the change of protein composition of a cell but with the general increase of proteins in its nucleus or cytoplasm.

Astrocytes↗

PubMed1976

Attempts at inhibition of autooxidation of catecholamines in vitro.

The authors attempted to inhibit autooxidation of catecholamines in vitro by means of sulphur-containing amino-acids, monosaccharides, and aminobutyric acids. The SH group-containing amino-acids were found to suppress autooxidation of catecholamines passing from a chloroform-methanol solution (2:1) to water or buffer solutions. A similar though less pronounced property was manifested by cysteic acid. Likewise glucose, fructose and galactose blocked the reaction. Among aminobutyric acids only gamma-aminobutyric acid inhibited autooxidation of amines. However, despite positive results obtained, these experiments cannot be utilized in studies on reduction of Nitro-BT, as no reduction of Nitro-BT occured in the solutions in which catecholamine autooxidation was brought to a stop.

Amino Acids↗

PubMed1976

Further studies on the possibility of differential demonstration of radicals of sulphur-containing amino-acids.

The authors showed that in rat liver and brain sections with blocked SH groups and split S-S bonds mercury orange stains some tissue structures after treating the sections with BAL. Considering that the blockade of SH groups with N-ethylmaleimide in is stable the authors set forth the hypothesis that the use of BAL may enable the demonstration of a sulphur-containing amino-acid which is devoid of SH or SS groups but acquires them only when acted upon by BAL. The in vitro studies demonstrated that the effect of BAL makes it possible to stain methionine with mercury orange which otherwise does not stain this amino-acid.

Amino Acids↗

PubMed1974