Biomedical subjects
Publications and source records attributed to P Ivanov.
Laparoscopic colorectal surgery had a somewhat difficult evolution. It is technically difficult, with a broad field of mobilization requiring multiple careful prot placement, need to deal with major vascular pedicles and the handling of larger surgical specimens. Aim of the present study is to make a comparison between laparoscopic and conventional colorectal surgery of cancer.
Temperature development of the relative stabilities of isomers of Mg@C72 (which has not yet been isolated) is computed using the recently introduced MNDO/d method. Four isomers originally considered for the Ca@C72 case are treated: one isolated-pentagon-rule (IPR) structure, two structures with a pair of adjacent pentagons, and one cage with a heptagon. The IPR structure comes as the lowest in MNDO/d potential energy, being rather closely followed by the two structures with a pentagon-pentagon pair. On the other hand, the structure with a heptagon is located too high in potential energy to be of any experimental significance. The entropy contributions are evaluated by the MNDO/d-based partition functions so that the relative concentrations can be treated accordingly. The computations suggest that if Mg@C72 is isolated, it should be a mixture of either two or three isomers. The prediction depends on temperature prehistory. If preparation takes place at temperatures of approximately 1000 K, two isomers should be produced. If temperatures are increased to approximately 2000 K, there will already be three isomers with significant relative concentrations. The study supplies a further interesting example of the profound role of enthalpy-entropy interplay in stabilities of isomeric fullerenic structures.
The article presents the results of the first regular study of Russian populations by sequencing the control region of mitochondrial DNA (mtDNA). The sequenced region is the most variable on mtDNA molecule and is commonly used for population and evolutionary studies. Russians form one of the largest ethnic groups (more than 129 million). However, their genetic diversity had only been characterized with RFLP and biochemical markers, although there are already established mtDNA sequence databases for many ethnic groups of the world. We have obtained sequence data from 103 individuals living in three Russian regions: Kostroma, Kursk, and Rjazan. The sequenced fragment analyzed is 360 bp in length (positions from 16024 to 16383). Fifty nine nucleotide positions have been found polymorphic in Russians, among those were 57 transitions and two transversions. One individual is found having two insertions of two cytosines between positions 16184 and 16193. Among 64 different mitotypes identified in the study 52 were unique in these samples. The index of genetic diversity (Nei, 1987) for Russians is 0.96. This value is within the established range for European populations (0.93 to 0.98). Genetic distances calculated from our data show that Russians form a cluster with Germans, Bulgarians, Swedes, Estonians, and Volgo-Finns are more distant from Karelians and Finns, and much more differ from Turks and especially Mongolians.
We have screened Thermotoga strains, isolated from hydrothermal vents near the Kuril Islands, for the presence of plasmid DNA. The miniplasmid pMC24 was isolated from the extreme thermophilic eubacteria Thermotoga maritima and sequenced, showing it to be a plasmid of 846 bp. It was found, from a search of the databases, to be closely related to the previously described Thermotoga miniplasmid pRQ7, isolated from a strain found on the Azore Islands, and was distinguished by only two point mutations. These changes resulted in two consecutive frameshifts altering a region encoding 9 amino acids in the Rep-coding region. We have also shown that pMC24, as with pRQ7, is negatively supercoiled. It seems that negatively supercoiled miniplasmids related to pRQ7 are spread worldwide and strongly maintained among Thermotoga strains.
An analysis of the behaviour of the soil system considered as an active medium with distributed energy sources was undertaken. This approach enabled the authors to build a heuristic model of soil which accounts for processes of organic substance production, migration and utilisation. The soil body is presented as a spatially distributed trophic chain with non-linear interactions of adjacent links. The level of this non-linearity appears to be the key parameter determining the dynamic behaviour of the model system in one-, two- and three-dimensional cases. The conditions for the existence of pulse-generating and autowave modes in this system were determined by computer simulations. Of particular interest is the behaviour of damaged soil, especially its self-regeneration potential. Inoculation autowave was proven to restore the initial state of the soil if two adjacent or separated trophic links fall out. Possible ways of the further development of the proposed model are also discussed.
A total of 60 patients with functional non-affective psychoses were assessed 16 years after their inclusion in the WHO co-ordinated study on reduction and assessment of psychiatric disability. All patients at inclusion had a recent onset of a psychotic disorder. About one-third of the patients had a good outcome. The rest showed moderate to severe psychiatric symptoms and social disability. Comparison with other similar studies suggested that our results show a low mortality rate, high levels of clinical symptoms, high levels of social disability and a low percentage of institutionalized patients. These findings are discussed in the context of the high level of family involvement in patients' care, which could reflect a cultural factor.
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The molar concentrations of the catalytic sites of serum cholinesterase (ChE--EC 3.1.1.8.) and cholinesterases (ChEs-acetylcholinesterase (AChE)--EC 3.1.1.7. and ChE) from brain and perfused liver of male birds, rats, swine and sheep were determined. A positive correlation between the molar concentrations of the catalytic sites of ChEs and the resistance of the animals to some organophosphorus compounds (OPhCs) was found. In addition, the present study also showed that the difference of the molar concentrations of catalytic sites of ChEs in the brain, blood serum and liver can cause varied resistance to some OPhCs.
Comparative studies were carried out on the inhibitory effect of some oleoemulsions on the acute course of an experimental coccidial infection caused by Eimeria tenella. Such effect was demonstrated with the oral application of sporulated oocysts both with the complete and incomplete Freund's adjuvant and with oleum ricini and oleum helianthi in combination. The results of histopathologic investigations showed that the two types of Freund's adjuvant inhibited the rapid and joint excysting of a large number of oocysts. Inhibited was the invasion of sporozoits in the epithelial cells of the mucous membrane and thus the acute course of the coccidial infection caused by Eimeria tenella.
Defined were the biochemical, phage, and antigenic properties of a total of 104 strains of S. aureus of the udder. It was found that by their biochemical behaviour 85 of the strains corresponded to var. ovis. Phage typing showed that the strains were lyzed in a highest percent by phages of groups IV and M. Dominating were the 42D/78/107/119 and 78 phages. Studies revealed that the strains were antigenically homogenic. Antigens h2 and k1k2 were characteristic of S. aureus var. ovis.
Both the 'counter' immunoelectrophoresis method and the complement-fixation test were employed to study a total of 767 samples of blood sera taken from rams. Five-hundred and seventeen of these were taken from ram flocks in which the infection was recorded by the clinical and the bacteriological method and the remaining 517 samples were taken from rams of intact flocks. A comparative evaluation was made of the two methods for the diagnosis of the disease when the animals were alive. Results made it clear that the 'counter' immunoelectrophoresis method was advantageous and could be used as a perspective adjunct in diagnosing the disease.
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Studied were the antigenic behaviours of S. aureus strains isolated from mastitis-affected cows on ten dairy farms, using factorial immune sera obtained against human S. aureus strains of a known antigenic structure. One hundred fifty (57 per cent) out of 263 strains proved typable, while 113 (43 per cent) did not produce positive agglutination reaction with any of the factorial sera. Considerable variation was established within the antigenic structure of S aureus. The k1, k2, b1, c1, n, and m antigens were most frequently encountered.
An immunoadsorbent was obtained from a lipopolysaccharide of Salmonella gallinarum-pullorum, employing the method of Eskenazy. It was used to adsorb the O agglutinating antibodies against S. gallinarum-pullcorum, S. enteritidis, S. heidelberg in blood sera of birds. Adsorption of sera was carried out at room temperature for 40 min. It was demonstrated that the product was highly specific. It fully and specifically found the O agglutinating antibodies in the sera of birds infected with S. gallinarum-pullorum and S. enteritidis and in the sera of birds coming from a flock with pullorum infection, however, did not bind the O agglutinating antibodies induced by the O antigens 4 and 5 characteristic of Salmonella heidelberg, resp., group B. A following investigation of the sera, using a S. heidelberg test-antigen, specified the sera of birds infected with S. heidelberg only. The application of the immunoadsorbent makes it possible to speed up the adsorption of the O agglutinating antibodies, and thus, for one or several hours within a single working day the differentiation is carried out of B and D Salmonella infections in birds.
Explored were the possibilities to differentiate the specific positive reactions in case of pullorum disease in experimentally infected (Salmonella gallinarum-pullorum and Salmonella enteritidis) birds with the use of a typhoid test antigen and two H test antigens, obtained by the routinely employed method with formalin from Salmonella enteritidis and Salmonella adeoyo. It was demonstrated that the H-agglutinating antibodies persisted in the peripheral blood of the experimentally infected birds for at least 30 days (as long as the test lasted). The H test antigen of S. enteritidis proved unsuitable to detect the H-agglutinating antibodies only as it retained to a large extent the O antigens. By means of the S. adeoyo H test antigen only the H-agglutinating antibodies in the peripheral blood of S. enteritidis-infected birds could be quickly and precisely demonstrated. A combined serologic examination of serum with the thyphoid test antigen and the S. adeoyo test antigen could be carried out to differentiate the specific positive reactions for establishing pullorum disease from the concomitant agglutination reactions observed in cases of experimental salmonellosis in birds caused by S. enteritidis.