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Biomedical subjects

T G Popova

Publications and source records attributed to T G Popova.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Comparative redundancy of genes of various organisms and viruses].

This paper is devoted to the comparative study of redundancy of genetic texts of various organisms and viruses. To determine the redundance of a gene, we have introduced the strict measure for that latter. The measure for a text's redundance is the length of restriction of Frequency/Correlation Dictionary of a given genetic text. Frequency/Correlation Dictionary is the ser of all subsequences belong to a given genetic text, accompanied by the frequencies of their occurrence. The restriction length is defined as that one, for which all the subsequences (of that length) are unique. We have found, that genes of human viruses are less redundant, in comparison to those of human genes. Other aspects of a comparative redundance investigations of the genes are discussed. The problem of the determination of "truet" intron could be treated by this methodology, as well, as the evolution of genome.

Amino Acid Sequence↗
PubMed1976

[Micromethod of ultracentrifugation in cesium chloride].

The micromethod of ultracentrifugation in cesium chloride is described. Band destributions have been analysed by the direct scanning of microtubes with the differential doublewave micro-spectrophotometer at 260 nm. The 10(-8)-10(-9) g of DNA or ribosomes are enough for one analysis, tube volume is 2 mul. The method described permits the simultaneous centrifugation of several probe scores. The error of the beyoant density determination is 0.001 g/sm3 relatively internal standard. DNA's from 5 types of Acetabularia were analysed by the developed technique.

Acetabularia↗
PubMed1975

DNA and RNA content of Chironomus thummi polytene chromosomes determined by micro column gel filtration.

A new microtechnique was used to determine the nucleic acid content of Chironomus polytene chromosomes. The method based on UV-microspectrophotometric measurement of alkali digested chromosome samples before and after gel filtration through Sephadex microcolumns permits the simultaneous estimation of DNA as well as RNA amount of single chromosomes and nucleoli. The DNA and RNA content of C. thummi salivary gland chromosomes I-III carrying a large number of puffs (but no nucleoli or Balbiani rings) corresponds roughly to their relative lengths. Chromosomes of the most frequent polyteny level (class B; probably 8192 C) contain 418 (Chromosome I), 372 (II), and 307 times 10-12 g DNA (III) and 116, 120 and 69 times 10-12 g RNA, respectively. The 4th chromosome, which carries the nucleolus and two Balbiani rings, contains about 150 times 10-12 g DNA and 328 times 10-12 g RNA. As the result of one of the last replication steps both DNA and RNA content of chromosomes I-III becomes duplicated whereas nucleolar RNA content is increased to a smaller extent.

Animals↗
PubMedDate not supplied

[Biological properties of polyoxyalkanoates in chronic experiments in vivo].

Chronic experiments on mature Wistar rats studied the biological properties of suture threads from two types of polyoxyalkanoates (POA), such as polyoxybutyrate (POB) and the copolymer of POB and polyoxyvalerate (POV) (POB/POV) as compared to the conventional surgical material (silk and catgut). The physiological and biochemical parameters that reflect the status of the animals, including their behaviour, height and development, the weight of the body and viscera, the morphology of peripheral blood, the biochemical parameters of blood, the activity of some enzymes, as well as histological findings of the viscera, and lymphoid tissue responses were assessed. POA was found to produce no negative effect on the physiological, biochemical, and functional characteristics of the animals irrespective of the duration of contact with the internal medium of the body and of the chemical composition of a material.

Animals↗
PubMedDate not supplied

[Classification of nucleotide sequences over their frequency dictionaries reveals a relation between the structure of sequences and taxonomy of their bearers].

Classification of 16S RNA sequences over their frequency dictionaries, both real ones, and transformed ones was studied. Two entities were considered to be close each other from the point of view of their structure, if their frequency dictionaries were close, in Eucledian metric. A transformation procedure of a frequency dictionary has been implemented that reveals the peculiarities of information structure of a nucleotide sequence. A comparative study of two classification developed over the real frequency dictionary vs. that one developed over the transformed frequency dictionary was carried out. The strong correlation is revealed between the classification and the taxonomy of 16S RNA bearer. For the classes isolated, the information valuable words were identified. These words are the main factors of a difference between the classes. The frequency dictionaries containing the words of the length 3 exhibit the best correlation between a class and a genus. A genus, as a rule, is included into the same class, and the exclusion are sporadic. A development of hierarchy classification over the transformed frequency dictionaries separated one or two taxonomy groups, as each stage of classification. The unexpectedly frequent, or contrary, unexpectedly rare occurred of words (of the length 3) in entities under consideration make the structure difference between the classes of the nucleotide sequences.

Bacteria↗
PubMedDate not supplied

[Temperature balance and the possibility of its maintenance during general anesthesia in children].

The problems of hypothermia in the perioperative period, which are one of the most important ones in pediatric practice, in babies in particular, are solved, by using a broad spectrum of methods for preventing and correcting the patients' thermal balance. Convection heating systems exercise an on-line control over the baby's thermal regime during a surgical intervention and intensive care. The authors' own experience allows these systems to be recommended for wide practical application in the activities of anesthesiology and intensive care services.

Anesthesia, General↗
PubMedDate not supplied

[General anesthesia using calypsol during angiographic study of the extremities in children].

In 17 children aged 7 to 14 years angiography of the extremities (AGE) was performed under general anesthesia by intravenous calypsol injection without premedication with cholinolytics (group I, monoanesthesia) or with premedication with atropine and neuroleptics (diazepam, droperidol; group II). It has been established that calypsol, in both groups, had a short-term moderate stimulating effect on the cardiac function and an insignificant effect on the respiratory function, which was not essential for the assessment of hemodynamic parameters during AGE. Muscle relaxation was more marked in children of group II, mainly due to the use of neuroleptics. In children of group II muscle relaxation was insignificant, this was associated with certain difficulties during AG. A technique of calypsol anesthesia during AGE in children has been elaborated, it is recommended to use calypsol in combination with neuroleptics, and to strengthen anesthesia by additional calypsol administration prior to the injection of contrast agents.

Adolescent↗