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Biomedical subjects

E A Smirnova

Publications and source records attributed to E A Smirnova.

At least 55 records · Page 3Linked to original sources
PubMed1995

Apoptosis-inducing and apoptosis-preventing functions of poliovirus.

Data showing that an apoptotic reaction (the exit into the cytoplasm and nucleolytic internucleosomal degradation of chromosomal DNA, compaction and fragmentation of chromatin, cellular shrinkage, and cytoplasmic blebbing) developed in a subline of HeLa-S3 cells upon nonpermissive poliovirus infection with either a guanidine-sensitive poliovirus in the presence of guanidine, a guanidine-dependent mutant in the absence of guanidine, or certain temperature-sensitive mutants at a restrictive temperature are presented. Essentially, no apoptotic reaction occurred upon permissive infection of these cells. Both permissive and nonpermissive infections resulted in the inhibition of host protein synthesis. Actinomycin D or cycloheximide also elicited a rapid apoptotic reaction in uninfected cells. However, preinfection or coinfection with poliovirus prevented the apoptotic response to the addition of actinomycin D, and preinfection blocked cycloheximide-induced apoptosis as well. These data fit a model in which the cells used are prepared to develop apoptosis, with their viability due to the presence of certain short-lived mRNA and protein species. Poliovirus infection turns on two oppositely directed sets of reactions. On the one hand, the balance is driven toward apoptosis, probably via the shutoff of host macromolecular synthesis. On the other hand, viral protein exhibits antiapoptotic activity, thereby preventing premature cell death. To our knowledge, this is the first description of an antiapoptotic function for an RNA virus.

Apoptosis↗
PubMed1995

[The prolymphocytic-lymphocytic leukemization of T-cell lymphosarcomas].

The paper presents a detailed clinical, hematological, morphological, ultrastructural and immunological characterisation of T-cell lymphosarcoma with prolymphocytic-lymphocytic leukemic transformation (PLLT). In PLLT the proportion of T-cell immunological subvariant of lymphosarcoma came to 15% being detected only in 8 out of 52 examinees. The patients (6 males and 2 females) varied in age from 24 to 76 years (median 49 years) and had the following histological forms of primary tumor tissue: lymphoblastic lymphosarcoma (n = 3), pleiomorphic small cell lymphosarcoma (n = 1), large-cell anaplastic lymphosarcoma (n = 1), prolymphocytic lymphosarcoma. Immunological characteristics of these 8 cases were heterogeneous: in lymphoblastic variant there was immature T-immunological phenotype. In pleomorphic small-cell lymphosarcoma there were also signs of T-cell activation. In large-cell anaplastic lymphosarcoma an immunological phenotype of lymphoid cells from the primary tumor tissue and bone marrow differed in more advanced immunological differentiation of bone marrow tumor cells. In prolymphocytic variant tumor cells had features of T-helpers or T-suppressors. Most of the patients received polychemotherapy according to the schemes for high-grade lymphosarcomas despite PLLT though the latter is not a universal indicator of late tumor progression, more aggressive course of the disease and poor prognosis.

Adult↗
PubMed1995

[Isolation and study of certain properties of caldesmon from cattle aorta].

A modified method for bovine aorta caldesmon isolation has been developed. When isolated from large vessels, caldesmon is copurified with connective tissue proteins whose molecular weight is similar to that of caldesmon. Separation of these proteins can be achieved by stepwise anion- (Q-Sepharose) and cation (phosphocellulose)-exchange chromatography. Bovine aorta and duck gizzard caldesmons have similar apparent molecular weights, absorption at 280 nm and one-dimensional peptide maps. Casein kinase II transfers about one mol of phosphate per mol of bovine aorta or duck gizzard caldesmon. In both cases, the sites of phosphorylation are located in the N-terminal peptides of apparent molecular weights of 26-28 kDa. It is concluded that there are no substantial differences between the structures and properties of avian gizzard and mammalian vessel caldesmons.

Animals↗
PubMed1994

Microtubule converging centers and reorganization of the interphase cytoskeleton and the mitotic spindle in higher plant Haemanthus.

We analyzed the distribution and orientation of transitory microtubule structures, microtubule converging centers, during interphase and mitosis in endosperm of the higher plant Haemanthus. In interphase the pointed tips of microtubule converging centers are associated with the nuclear envelope. Their orientation gradually reverses during prophase, and the tips tend to point away from the nucleus. From prometaphase through early telophase, microtubule converging centers are present predominantly in the cytoplasm at the polar region. They are either "free" or associated with chromosomes or microtubule bundles. In late telophase, pointed tips of microtubule converging centers are again associated with the reconstructed nuclear envelope and, additionally, they often appear in the phragmoplast area. The orientation of microtubule converging centers seems to be directly correlated to the previously determined microtubule polarity, with the converging tip being minus and the diverging one, plus. Elevated temperature (35 degrees-37 degrees C) enhances the number of microtubule converging centers in the cytoplasm and at the nuclear envelope. This is especially pronounced during the telophase-interphase transition and in some interphase cells, indicating temperature and stage dependence. Our data imply that microtubule converging centers bind together MT minus ends and, thus, control the predominant direction of elongation and shortening of microtubule arrays. We argue that these configurations are instrumental during the reorganization of interphase cytoskeleton and mitotic spindle in Haemanthus endosperm.

Cell Cycle↗
PubMed1993

Uterine sarcomas in CBA mice induced by combined treatment with 1,2-dimethylhydrazine and estradiol dipropionate. Light and electron microscopy.

Three uterine sarcomas induced by combined treatment (1,2-dimethylhydrazine and estradiol dipropionate) in CBA mice were examined by light and electron microscopy. Histologically the tumours consisted either of loose areas with stellate cells or of solid cellular areas. These were formed of elongated cells of the fibroblastic type and rounded cells with clear nuclei and abundant cytoplasm without clearly discernible bodies. Ultrastructurally, undifferentiated mesenchymal cells and cells with the features of fibroblasts and myofibroblasts were distinguished. The tumours described bear resemblance to human endometrial stromal sarcomas and are interpreted as sarcomas originating from immature mesenchymal cells differentiating mainly in the direction of cells of the fibroblastic type. Certain similarities with fibrous histiocytomas are noted.

1,2-Dimethylhydrazine↗
PubMed1992

[Ultrastructure of pulmonary squamous cell carcinoma as a prognostic factor in surgical treatment].

163 operated on patients were divided into 2 groups: the 1st group--those surviving 5 years without recurrence (44.2%) and the 2nd group--those dying earlier from the tumour progression (55.8%). Central carcinoma was in 104, peripheral one in 59 cases. The number of dark cells (DC) and the degree of desmosome development revealed ultrastructurally have the greatest practical importance as the favourable course in the 1st group was associated with the absence or low number of DC (7%) and the high number of desmosomes (89%). These indices were found in the 2nd group in 86 and 41%, respectively. Both indices are of independent importance and are not associated with the spread of the carcinoma. The level of DC is of greater importance. Prognosis of the squamous cell carcinoma is the worse the higher is DC number in the tumour and the lower the desmosome number.

Carcinoma, Squamous Cell↗
PubMed1992

Isolation, crystallization in the macrogravitation field, preliminary X-ray investigation of uridine phosphorylase from Escherichia coli K-12.

Uridine phosphorylase (UPH) from Escherichia coli K-12 has been purified to near homogeneity from a strain harbouring the udp gene, encoding UPH, on a multicopy plasmid. UPH was purified to electrophoretic homogeneity with the specific activity 230 units/mg with a recovery of 80%, yielding 120 mg of enzyme from 3g cells. Crystals of enzyme suitable for X-ray diffraction analysis were obtained in a preparative ultracentrifuge. The packing of the molecules in the crystals may be described by the space group P2(1)2(1)2(1) with the unit cell constants a = 90.4; b = 128.8; c = 136.8 A. There is one molecule per asymmetric unit, Vm = 2.4. These crystals diffract to at least 2.5-2.7 A resolution. The hexameric structure of UPH was directly demonstrated by electron microscopy study and image processing.

Crystallization↗
PubMed1991

Three-dimensional structure of the nickel-containing hydrogenase from Thiocapsa roseopersicina.

The three-dimensional structure of the nickel-containing hydrogenase from Thiocapsa roseopersicina has been determined at a resolution of 2 nm in the plane and 4 nm in the vertical direction by electron microscopy and computerized image processing on microcrystals of the enzyme. The enzyme forms a large ring-shaped complex containing six each of the large (62-kDa) and small (26-kDa) subunits. The complex is very open, with six well-separated dumbbell-shaped masses surrounding a large cylindrical hole. Each dumbbell is interpreted as consisting of one large and one small subunit.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

[The ultrastructural characteristics of different histological types of bronchiolar-alveolar cancer].

Morphological study of bronchioloalveolar carcinoma (BAC) was performed by light or electron microscopy in 100 and 33 patients, respectively. BAC-1, 2 and 3 histologic subtypes were established basing on ultrastructural peculiarities which betrayed different cytogenetic origins. Electron microscopic signs of goblet cells were found in cells constituting BAC-1 tumors. BAC-2 tumor cells exhibited ultrastructural characteristics of Clara cells and/or type-II pneumocytes. BAC-3 tumors appeared less differentiated and contained mainly undifferentiated cells and cell clusters displaying various combinations of electron microscopic markers of goblet and Clara cells and type-II pneumocytes.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1990

[The ultrastructural characteristics of human lung adenocarcinomas as a factor in the prognosis in surgical treatment].

The material of 70 patients with lung adenocarcinomas radically operated at the All-Union Cancer Research Centre is analyzed. The spread of tumour expressed in terms of TNM system (I group--T1-3 N0M0--37 patients, II group--T1-3 N1M0--18 patients, III group--T1-3 N2M0--11 patients, IV group--T1-3 N1M1--4 patients) and its ultrastructure served as criteria. The correlation is found between the life-span, degree and type of the tumour cell ultrastructural differentiation. The most favourable prognosis at comparable tumour spread is found when the tumour cell ultrastructural differentiation corresponded to that of Clara type, pneumocytes of II order and ciliary type. Less favourable ultrastructural features were the domination of undifferentiated cells and the presence of goblet cells and those having the signs of differentiation into the various directions. The lack of correlation of the differentiation at the light microscopic and ultrastructural levels is found in some cases this being reflected in delayed results.

Adenocarcinoma↗
PubMed1990

[Malignant ovarian struma].

A rare observation of an unilateral ovarian tumour in a 62-year-old patient is presented. According to the clinical data and the results of the ultrasound examination the tumour was considered as a carcinoma. Hysterectomy with appendages and large omentum resection were performed. A tumour of the right ovary, 13 x 10 x 10 cm was found: cyst with a grey-brown soft node was observed in the cut surface. Histologically, the struma remnants were observed in the cyst wall and structures corresponding to the follicular carcinoma of the thyroid, the central parts of which had a structure of the C-cell thyroid carcinoma. Ultrastructural examination confirmed a light microscopic diagnosis of the malignant monodermal ovarian teratoma developing from the struma with areas of follicular solid C-cell carcinoma.

Female↗