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Biomedical subjects

A Jerzmanowski

Publications and source records attributed to A Jerzmanowski.

At least 37 records · Page 2Linked to original sources
PubMed1983

Immunoglobulins and complement in migraine.

In 54 patients with migraine and 70 persons comprising the control group, the total complement level (CH50) was evaluated together with its C3 and C4 fraction level and the level of IgG, IgA and IgM immunoglobulins. It was found that the average C3 fraction level was significantly decreased, while the C4 fraction level and total complement activity remained in the normal range. The immunoglobulin level did not show any statistically significant alterations except for the IgA level, which was lowered in migraine patients. On this basis, i.e. lowering of the C3 fraction level with normal C4 fraction level and total complement activity and lack of elevation of IgA, it is felt that the alternative pathway of complement system may be activated in migraine.

Adolescent↗
PubMed1980

Some unusual features of Physarum polycephalum chromatin are due to the presence of slime.

Chromatin of lower eukaryote Physarum polycephalum, while showing typical nucleosomal organization, reveals upon digestion with micrococcal nuclease certain features not found in chromatins of higher eukaryotes, the most pronounced of which is the unusual pattern of degradation of core-size DNA, without accumulation of subcore fragments. It has been shown that these peculiarities are not due to intrinsic features of Physarum nucleohistone complex but to the presence of a specific polysaccharide, the main component of Physarum slime, contaminating chromatin preparations.

Animals↗
PubMed1979

Chromatin condensation. Possible dehydrating and stabilizing factors.

The effect of Na+, Mg2+, spermidine and spermine on the dehydration of chromatin gel and precipitation of soluble chromatin has been compared. Considerable differences have been found in the relative ratios within the studied group (Na+, Mg2+, spermidine and spermine) between the ability to dehydrate (1 : 32 : 53 : 67) and to precipitate (1 : 53 : 800 : 2000) chromatin. On the basis of the dependence of precipitation on initial chromatin concentration it has been suggested that the observed effect as contributed considerably by interparticle aggregation is a relatively good measure of the ability of cation to stabilize higher order structures of chromatin through direct crosslinking or induction of hydrophobic associations at selected sites. In contrary to that the method estimating the direct dehydration measures the overall dehydrating effect of a cation exerted on the whole chromatin. It has been suggested on the basis of the above comparative data that the in vivo regulation of the degree of overall chromatin hydration should occur through changes in concentration of free small inorganic cations. Larger organic polycations like polyamines should be mainly involved in stabilization of the higher order chromatin structures. The stabilizing role of large polyanions like RNA has been ruled out. It has also been found that the unwinding of chromatin DNA results in considerable chromatin hydration.

Animals↗
PubMed1978

Effect of ethidium bromide on the digestion of chromatin DNA with micrococcal nuclease.

Intercalation of ethidium bromide into DNA influences the rate of its digestion with micrococcal nuclease in opposite directions depending on whether it is free DNA or DNA in chromatin. In the case of free DNA the binding of ethidium bromide, starting from a very low concentration, results in the inhibition of the rate of digestion (increasing constantly with the increase of the ethidium bromide/nucleotide ratio). In contrast to free DNA the digestion rate as well as the overall amount of nuclease susceptible DNA is increased upon ethidium bromide binding to chromatin, with maximum enhancement around the saturation of intercalation sites. The saturation of intercalation sites in chromatin leads also to the disappearance of the typical micrococcal nuclease digestion pattern of DNA upon gel electrophoresis. Instead, a random cleavage pattern is observed. These data indicate that partial unwinding of chromatin DNA by ethidium bromide results in unmasking new sites for nuclease action. Interpretation of this finding in terms of the nucleosomal structure of chromatin and the mode of ethidium bromide binding to chromatin DNA indicates that newly unmasked sites are localized within the core particle DNA.

Animals↗
PubMed1978

Comparison of susceptibility to staphylococcal nuclease and behaviour in metrizamide gradients of normal and 5-bromodeoxyuridine-substituted chromatin from Physarum polycephalum.

Replacement of 20--30% of thymine by 5-bromodeoxyuridine in chromatin DNA of Physarum polycephalum does not cause any visible change in a typical, regular pattern of DNA products obtained upon digestion of chromatin with staphylococcal nuclease. The time course of digestion is similar for normal and substituted chromatin even under conditions when the nuclease cleaves preferentially the dAT regions in DNA. 5-Bromodeoxyuridine label does not significantly affect the DNA/protein ratio in chromatin; this is reflected by similar behaviour of normal and substituted chromatin in metrizamide-density gradients.

Bromodeoxyuridine↗
PubMed1977

Nucleoprotein chromatin subunit from Physarum polycephalum.

The nucleoproteins resulting from digestion of the nuclei of the true slime mold Pysarum polycephalum with micrococcal nuclease have been resolved according to the size classes in linear sucrose gradients containg 0.5 M NaCl, and analysed for DNA, RNA and protein content. The basic nucleoprotein subunit has been found to contain a DNA fragment of about 150--170 base pairs complexed with an approximately equal amount, on a weight basis, of basic proteins and a relatively small amount of non-histone proteins (about 35% of the amount of DNA). Higher nucleoprotein oligomers were shown to contain spacer DNA fragments between adjacent subunits and a considerably higher ratio of non-histone proteins to DNA than the basic subunit. Both the basic subunit and higher nucleoprotein oligomers of Physarum chromatin contain some amount of tightly bound RNA. However, in contrast to the distribution of the non-histone proteins, the ratio of RNA to RNA is similar in both fractions.

Chromatin↗