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Biomedical subjects

A V Ivanov

Publications and source records attributed to A V Ivanov.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Complications of implantation of the cava filter "Réptéla"].

The article describes a complication resulting from the implantation of a cava-filter for roentgen endovascular prophylactics of thromboembolism of the pulmonary artery (REPTEPA) to a 68 years old woman with recurring thromboembolism of the pulmonary artery, floating thrombus of the right iliac vein. An attempt to disconnect the cava-filter from the applicator after implantation proved to be unsuccessful which was followed by urgent operation: marginal resection of the vena cava inferior with the cava-filter, suture of the vein, cava plication. The nearest postoperative period was complicated by thrombosis of the plication zone. The examination in 6 months has shown the formation of the syndrome of the vena cava inferior.

Aged↗
PubMed2000

[Clinical characteristics of patients emergently hospitalized with pulmonary hemorrhage].

Analyzing the data on 1812 patients with respiratory diseases, mainly pulmonary tuberculosis, urgently admitted to a tuberculosis hospital for the pulmonary hemorrhage (PH) syndrome during 5.5 years showed that there was no seasonal prevalence in the development of a complication. There was a steady-state regularity of the prevalent admission of patients to hospital from 10 a.m. to 8 p.m. and no hemorrhage in 39% of them on admission. Evidence was provided for the low diagnostic value of hemoptysis in assessing the prediction of the developed PH syndrome. In PH syndrome, the hospital mortality decreased by 2.6 times (from 20.0 to 7.7%) due to a wider use of the artificial hypotension method, endoscopic bronchial blockade, to the development and introduction of new modes of intraoperative protection and sanitation of the tracheobronchial tree, to the prevention of asphyxia, hemo-aspiration pneumonia, and its pathogenetically resultant acute progression of tuberculosis.

Adolescent↗
PubMed1999

P53-dependent effects of RAS oncogene on chromosome stability and cell cycle checkpoints.

Mutations activating the function of ras proto-oncogenes are often observed in human tumors. Their oncogenic potential is mainly due to permanent stimulation of cellular proliferation and dramatic changes in morphogenic reactions of the cell. To learn more on the role of ras activation in cancerogenesis we studied its effects on chromosome stability and cell cycle checkpoints. Since the ability of ras oncogenes to cause cell transformation may be dependent on activity of the p53 tumor-suppressor the cells with different p53 state were analysed. Ectopic expression of N-ras(asp12) caused in p53-deficient MDAH041 cell line an augmentation in the number of chromosome breaks in mitogenic cells, significant increase in the frequency of metaphases showing chromosome endoreduplication and accumulation of polyploid cells. Similar effects were induced by different exogenous ras genes (N-ras(asp12), H-ras(leu12), N-ras proto-oncogene) in Rat1 and Rat2 cells which have a defect in p53-upstream pathways. In contrast, in REF52 and human LIM1215 cells showing ras-induced p53 up-regulation, ras expression caused only slight increase in the number of chromosome breaks and did not enhance the frequency of endoreduplication and polyploidy. Inactivation in these cells of p53 function by transduction of dominant-negative C-terminal p53 fragment (genetic suppressor element #22, GSE22) or mutant p53s significantly increased the frequency of both spontaneous and ras-induced karyotypic changes. In concordance with these observations we have found that expression of ras oncogene caused in p53-defective cells further mitigation of ethyl-metansulphonate-induced G1 and G2 cell cycle arrest, but did not abrogate G1 and G2 cell cycle checkpoints in cells with normal p53 function. These data indicate that along with stimulation of cell proliferation and morphological transformation ras activation can contribute to cancerogenesis by increasing genetic instability.

Animals↗
PubMed1999

[Clinico-anatomical significance of the presence of blood in the gastrointestinal tract of patients who died of pulmonary hemorrhage].

Examining the follow-up and autoptic data on 133 patients who died from pulmonary hemorrhage in the presents of respiratory diseases, including tuberculosis has revealed a previously undescribed a phenomenon of the presence of blood varying in its pattern and volume in the proximal and distal gastrointestinal tract. The clinical and anatomic assessment of the phenomenon detected and its value in the patho- and thanatogenesis of asphyxial pulmonary hemorrhages are given. It is concluded that asphyxial hemorrhages do not develop suddenly, but they result from pulmonary hemorrhages lasting 1-2 days or more, wherein the patients digest great volumes of blood. The digesting of blood rather than its coughing away is observed in patients with mental disorders, during a deep or abnormal sleep, and in the agonal period of asphyxia. The paper shows the significance of the revealed phenomenon as a constituent of total blood loss and a cause of undiagnosed pulmonary hemorrhage in 24% of dead individuals.

Adult↗
PubMed1999

[Preparation and certain properties of the liposomal substance 2,4-di(1-methyl-3-hydroxybutyl)deuteroporphyrin-IX].

A liposome preparation of a porphyrin photosensitizer for photodynamic therapy of tumors (PDT) was obtained. The in vitro efficiency of the photosensitizer was enhanced 2.5-fold through the liposome formulation. The composition and some properties of the new preparation were studied. An algorithm for a complex approach to the prediction of photosensitizer efficiencies by model experiments in vitro was developed. This approach is based on the use of two models: the determination of coefficient of distribution between n-octanol and a phosphate buffer, pH 7.4, and the determination of the cytotoxic effect on the culture of CaOv ovarian adenocarcinoma cells.

Adenocarcinoma↗
PubMed1997

[The use of laser and phototherapy in the comprehensive treatment of malignant tumors and leukemia in children].

The report deals with the development of procedures, evaluation of laser application and prevention of complications involved in intensive chemoradiation therapy of neoplasms of hemopoietic and lymphoid tissue in childhood. The clinical data on 548 patients, aged 2 months-15 years, with leukemia and solid tumor were evaluated. Laser application for treatment of different complications of chemoradiation therapy of pediatric leukemia proved a valuable innovation. It had a pronounced antiinflammatory and analgetic effect, promoted tissue regeneration processes and cut down the duration of complication treatment drastically.

Adolescent↗
PubMed1996

Chromosome changes caused by alterations of p53 expression.

It has been proposed that p53 tumor-suppressor plays a key role in maintaining genome integrity in mammalian cells. We analyzed karyotype alterations in human and murine cell sublines expressing various exogenous human mutant (His175, Trp248, His273) or wild-type (wt) p53 cDNAs. In human pseudodiploid LIM1215 cells that contain two endogenous wt-p53 gene alleles, p53 mutants caused both an increase in the frequency of chromosome breaks and an emergence of hyperdiploid cells. Murine T12-/- and 10(1) fibroblasts lacking endogenous p53 expression have very unstable karyotypes and show a strong tendency to increase their ploidy levels during growth in culture. Transduction of a wt-p53 construct into p53-deficient cells inhibited an accumulation of highly polyploid cell variants. Transduction of mutant p53 did not show such an effect. Modification of endogenous and exogenous p53 expression by caffeine, which interferes with normal induction of p53 in response to DNA damage, showed no correlation between the induction of chromosome breaks and heteroploidy. We conclude that the caffeine- or mutant p53-induced increase in the frequency of chromosomal breaks in dividing LIM1215 cells is assonated with inactivation of wt-p53 function(s) responsible for control of G1 checkpoint and/or DNA repair, while numerical chromosome changes in these cells may be a result of elimination or modification of a separate p53 function, or due to gain-of-function activities of p53 mutants. p53 modifications may therefore cause chromosome instability by different pathways: (1) through changes in the system(s) preventing proliferation of cells with genomic alterations; and (2) by increasing the probability of events, such as chromosome non-disjunction and/or endoreduplication that can lead to chromosome gains.

Animals↗
PubMed1996

Characterization of the human small-ribosomal-subunit proteins by N-terminal and internal sequencing, and mass spectrometry.

Reverse-phase HPLC was used to fractionate 40S ribosomal proteins from human placenta. Application of a C4 reverse-phase column allowed us to obtain 27 well-resolved peaks. The protein composition of each chromatographic fraction was established by two-dimensional polyacrylamide gel electrophoresis and N-terminal sequencing. N-terminally blocked proteins were cleaved with endoproteinase Lys-C, and suitable peptides were sequenced. All sequences were compared with those of ribosomal proteins available from data bases. This allowed us to identify all proteins from the 40S human ribosomal subunit in the HPLC elution profile. By matrix-assisted laser-desorption ionization mass spectrometry the masses of the 40S proteins were determined and checked for the presence of post-translational modifications. For several proteins differences to the deduced sequences and the calculated masses were found to be due to post-translational modifications.

Amino Acid Sequence↗
PubMed1996

[Methods for diagnosing the physiopathological mechanisms of bronchial obstruction].

This study aimed at clarification of pathophysiological mechanisms underlying bronchial obstruction in 28 18-71-year-old patients with chronic bronchitis (CB) diagnosed 2-8 years before. The patients had moderate obstructive disorders in distal parts of the bronchial tree. Investigations revealed a group of patients with paradoxical response to beta-blockers manifesting as lowering of bronchial resistance and high speed. Bronchial obstruction in these patients proved to arise primarily from early expiratory collapse of small bronchi. Administration of beta-mimetic and beta-blocking agents may serve as pharmacological tests able to discover mechanisms of bronchial obstruction and help in the choice of adequate therapy for chronic bronchitis.

Adolescent↗
PubMed1996

[Induction of hyperdiploidy and chromosome breaks in LIM1215 cells expressing the exogenous mutant p53].

The effect of modifications of p53 expression on the incidence of numerical and structural chromosome aberrations was studied. Infection of LIM1215 cells containing two alleles of the wild-type p53 gene (P53wt) with the recombinant viruses that expressed mutant cDNAs coding for human p53 (His273, Trp248, and His175) resulted in appearance of hyperdiploid cells in populations and an increased proportion of metaphases with chromosome breakage. Expression of the exogenous p53wt or vectors HSG/neo and pPS/neo, which did not contain the p53 cDNA, did not induce numerical or structural chromosome aberrations. Treatment of cells with caffeine decreased the p53wt content and increased the proportion of metaphases with chromosome breaks; however, it did not induce hyperdiploidy in the majority of cell lines. Only in the subline that expressed the exogenous p53Trp248 did caffeine treatment increase the proportion of hyperdiploid variants, which was correlated with the hyperexpression of the product of the mutant allele. The increase in the frequency of chromosome breaks probably resulted from p53wt inactivation, whereas changes in chromosome number might be induced by some additional activities of p53 determined by mutations. Possible mechanisms for inducing heteroploidy by mutant p53 variants, including the role of endoreduplication in inducing hyper- and polyploidy, are discussed.

Cell Line↗
PubMed1993

[Epidemiologic and clinical-physiological evaluation of chronic bronchitis in industrial workers].

A random select of 2350 heavy engineering industry workers was exposed to an epidemiologic examination. Cardiopulmonary functional resources were dramatically decreased in the examinees with epidemiologically proven chronic bronchitis. Functional status of the respiratory system appeared to correlate with the risk factors in common with certain noninfections diseases. High prevalence of smoking among the chronic bronchitis patients, in women to the major extent, makes the anti-smoking struggle actual.

Bronchitis↗