Biomedical subjects
Publications and source records attributed to V Ivanova.
In a series of fifty-two patients undergoing abdominal surgery the listed below agents for postoperative analgesia are used: moradol (M), dipidolor (D), droperidol--DNBP, fentanyl (F). The control group is given analgin. During the first six hours, M and D show optimal effect in terms of postoperative pain syndrome relief, without suppression of the hemodynamics and respiration.
Immobilized cells of Bacillus licheniformis 44MB82-G were used for the production of thermostable alpha-amylase. The immobilization was carried out by entrapment in agar gel or by binding to formaldehyde-activated acrylonitrile/acrylamide membranes. The alpha-amylase production after 144 h of cultivation of membrane immobilized cells was 40% higher in comparison with the free cells. The respective value for the agar-entrapped cells was 22%. Similar trends were observed in the repeated batch fermentations performed with the immobilized cells. The scanning electron micrographs (SEM) of the immobilized cells gave additional information about their binding to the respective carriers.
A polysaccharide from the green marine algae Ulva lactuca has been isolated. The substance has been investigated after acid hydrolysis by thin-layer and gas chromatography. The following carbohydrate components have been found: arabinose-xylose-rhamnose-galactose-mannose-glucose in ratio 1:1:9:5:2.5:16 respectively. One unidentified sugar has been demonstrated too. The polysaccharide has been studied for antiviral activity in vitro against a number of human and avian influenza viruses. A considerable inhibition of the viral reproduction was found. The effect was dose-dependent, strain-specific and selective.
To help elucidate the factors regulating the expression of histone multigene families in proliferating cells, we asked whether the relative expression of different members of such a family was dependent upon or independent of the type of proliferating cell. This question was examined by measuring the relative expression of seven members of the human histone H2A multigene family in four cell lines of diverse origin. Two previously uncharacterized members of the H2A gene family were found to be the most abundantly expressed of the seven in all four cell lines. One of these encodes an H2A.2 species containing methionine. The lines examined in the study were Jurkat (a lymphoma line), N-tera (a pluripotent embryonic carcinoma line), HeLa (originally isolated as a cervical carcinoma), and IMR90 (a normal embryonic fibroblastic line). The amount of each mRNA species was quantitated using oligonucleotides about 30 bases long complementary to the 5' or 3' untranslated regions. In each cell line, there was at least an eight-fold difference in the amount of the most and least highly expressed of the seven H2A mRNA species. In addition, there were up to five-fold differences among the cell lines in the amount of the H2A mRNA species as a fraction of total RNA. However, in contrast to those differences, the four cell lines were found to express the seven H2A mRNAs in similar relative amounts. These findings suggest that the relative expression of the individual members of a histone gene family is independent of the type of replicating cell.
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This paper reports the initial experiments for genetic analysis of the haploid methylotrophic yeast Candida boidinii PLD1. The collection of multiply marked auxotrophic mutants was obtained after treatment with UV-light or X-rays. Protoplasts from several mutants were fused by the PEG-CA2+ technique and five prototrophic hybrids were isolated. The genetic structure of the hybrids was studied by means of spontaneous and induced mitotic segregation. Our data suggest that hybrids are diploids, heterozygous by parental auxotrophic markers. We obtained genetic linkage between mutations lys2-8-met-3 from one hand and ade-17-arg-24 from the other. The genetic maps constructed showed similar characteristics concerning both the order of the markers and their map distances.
Morphological, cultural and physiological-biochemical properties of Streptomyces sp. strain 1000 and its antibiotic production were investigated. Antibiotics 1011 (identical with the streptovaricin complex) and 1012 (with antibacterial action) were isolated from the cultural broth of this strain. The overproducing natural variant 1011 was isolated from the population of a strain producing antibiotic 1011 at a concentration of 1000 mg/L (activity of the parent strain represents 41 mg/L only). Comparative taxonomical characteristic of Streptomyces sp. strain 1000 with strains from S. spectabilis showed that the strain 1000 differed in some properties and antibiotic production being considered as a new variant of S. spectabilis. The strain shows an expressed antibiotic activity against G+ as well as G- bacterial and yeasts.
With the aim of characterizing further the anticonvulsive activity of the newly-synthesized barbituric derivative 2-hydroxylamino-5-ethyl-5-sec. penthylbarbituric acid (HB-7), we studied its effects on allylglycine-induced epileptiform electrocorticogram (ECoG) in cats under acute conditions. Pentobarbital (PB) was used for comparison. Allylglycine (AG) was administered in a dose of 100 mg/kg i.v. to all cats. The control animals were treated with AG only. HB-7 and PB were applied in doses of 20 mg/kg i.p., about 60 min after AG. Intermittent light stimulation (ILS) at flash rate of 8/s and 25/s was applied to some animals. The ILS-stimulated animals were also divided in three groups: controls and animals treated with HB-7 or PB in the same dose. AG led to the appearance of paroxysmal ECoG activity: single and multiple spikes and spike-waves appeared first, to be followed later by generalized seizure activity. No AG-induced convulsions appeared in the cats treated with HB-7, but the AG-induced spikes and spike-waves remained unchanged. The effect of PB on the AG-induced paroxysmal ECoG activity was similar to that of HB-7, but the addition of PB provoked the appearance of slow waves and spindles, mixed with spikes and spike-waves. Although the paroxysmal character of the activity was more pronounced in the ILS-stimulated animals than in the group without ILS, HB-7 and PB (albeit to a lesser extent) inhibited the AG-induced discharges.(ABSTRACT TRUNCATED AT 250 WORDS)
Comparative tests were performed on male albino rats to study the activity of the original hydroxylamine barbiturate HB-7, with phenobarbital (PhB) and pentobarbital (PB) using the conflict situation test (after Vogel et al., 1971) with thirsty rats (deprived of water for 48 hours). The three barbiturates studied (HB-7, PhB and PB) were administered intraperitoneally in four doses (5, 10, 15 and 20 mg/kg). Two parameters were registered: number of punished responses (electrical shocks punishing attempts to drink) and the number of non-punished responses (approaching the drinking tube) for the 5-min period of observation. In a second group of experiments the same test was used to study the effect of picrotoxin and of its combinations with the effective doses of HB-7, PhB and PB. The three barbiturates tested were found to have an anxiolytic effect, i.e. to increase the number of attempts to drink water, in the higher doses used. Picrotoxin causes a decrease in the number of punished responses (anxiomimetic effect). When HB-7, PhB and PB are combined with picrotoxin, the latter eliminates their anxiolytic action. The conclusion reached is that the anxiolytic action of the barbiturates tested is probably connected with an effect on the GABA-ergic transmitter system in the central nervous system.
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Acetic acid and furfural are normal components of the yeast hydrolysates. The influence of acetic acid in different concentrations (from 2 to 10 g/dm3) and furfural (from 0.2 to 0.8 g/dm3) on the growth of 8 yeast strains from the genus Candida under cultivation in synthetic nutrient media has been studied. It was established that some yeast strains absorb acetic acid better at pH 4.0-5.0, while others--only at pH 6.0 and at different concentrations of the acid in the nutrient media. Acetic acid in concentrations from 2 to 4 g/dm3 suppresses growth entirely in some strains, while in others growth was established. Acetic acid in concentrations over 8 g/dm3 inhibits growth in all 8 strains of the studied yeasts. Furforal in concentration to 0.4 g/dm3 in the synthetic nutrient media inhibits the growth in the 8 strains to a certain extent, while in concentration over 8 g/dm3 it stops the growth in all 8 yeast strains.
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Modification of H2a variants with radioactive iodine was used to study under different ionic conditions the accessibility of their tyrosine residues in chromatin, in monosomes and when free in solution. The modification of tyrosine 57 in the hydrophobic part of H2a was found responsible for the appearance of new fractions with a reduced electrophoretic mobility in the presence of Trition X 100, detected only by autoradiography (radioactive "ghosts"). At low ionic strength a very small number of molecules were iodinated in chromatin, the modification affecting only their hydrophobic region. At moderate ionic strength the tyrosine residues near the N-terminal region of the molecule were predominantly modified. In chromatin the accessibility of the tyrosine residues of H2a1 was much greater than that of H2a2, a difference not observed with free histones.
After oxidation of the catalytically active sulfhydryl group of Cys-149, glyceraldehyde-3 phosphate dehydrogenase is known to acquire an acylphosphatase activity. Modification of one cysteine residue, obviously Cys-153, with p-mercuribenzoate or N-ethylmaleimide fully inactivates the phosphatase activity of the oxidized enzyme suggesting that this amino acid residue is involved in the reaction. An acyl transfer between Cys-153 and the sulfenic acid derivative of Cys-149 in the mechanism of the phosphatase reaction could explain the data obtained. Compounds which contain heteroatoms at two adjacent carbon atoms such as alpha-amino acids, peptides, EDTA and o-phenanthroline are shown to inhibit the phosphatase reaction of glyceraldehyde-3-phosphate dehydrogenase. These compounds bind in the active centre region close to Cys-153 and may interfere with the acyl transfer reaction thus inhibing the overall phosphatase reaction.