[Internet resources on electron microscopy].
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Internet↗
Biomedical subjects
V P Chernikov
Publications and source records attributed to V P Chernikov.
[The presence of cesium-137 in the tissue of a lung tumor in someone who cleaned up the aftermath of the accident at the Chernobyl Atomic Electric Power Station].
A man of 66 participated in the emergency works after the Chernobyl accident. His official dose of radiation comprised 24 roentgens. In March, 1993, he underwent prophylactic examination including computed tomography which revealed peripheral tumor in the lower part of the left lung with penetration in the lymph nodes of the lung root. Biopsy showed it to be adenocarcinoma. Moreover, electron-microscopically, more than 40% of alveolar macrophages contained large optically dense particles in the cytoplasm. After lobectomy in March 1993 x-ray and gamma spectrometry of the removed lung tissue recorded high content of 137Cs (0.1-0.18 Bq). This finding evidences possible long-term deposition of radionuclides in the bronchopulmonary system of radiation-exposed subjects.
Adenocarcinoma↗
[The effect of weightlessness on amphibians. The skeleton and mineral metabolism].
The visceral and somatic skeleton of Pleurodeles waltilii was investigated after a series of two-week space flights on the biosatellites. It was shown that under conditions of weightlessness osteoporosis of the skeleton and its demineralisation were stimulated. In weightlessness, calcium, phosphorus and sulfur were lost and potassium accumulated. Trabeculae of endochondral part of the extremity bones were destroyed by osteoclasts. Proliferation of osteoclasts was disrupted, appositional growth stopped, and the cartilage of hyoid system was resorbed. Skeleton readaptation during two months did not result in the complete regeneration of morphological structure of the bones.
Adaptation, Physiological↗
[Ultrastructure and interaction of normal killer cells from human blood and target cells sensitive to them].
Morphological properties of cells possessing a natural cytotoxic activity obtained from blood of healthy persons have been studied, as well as the process of their interaction with sensitive target-cells (K-562). By means of electron microscopy, during incubation at 37 degrees C, appearance of specific morphological manifestations of cytolytic action of the effector-cells forming rather tight contacts with the target-cells (vacuolization of cytoplasm, ring-form defects in plasmalemma, subsequent destruction of the target-cells) has been followed. Morphological features of cytotoxic leucocytes are similar to the morphological criteria specific for T gamma (T-lymphocytes possessing receptors for Fc-fragment of immunoglobulin G) and zero lymphocytes: a rather low nuclear-cytoplasmic ratio, a well developed Golgi complex, a rather great amount of mitochondria.
Cell Communication↗
[Structural characteristics and oxidative phosphorylation of the isolated mitochondria from the rabbit small intestine epithelium under normal conditions and under the effect of choleragen].
Mitochondrial fraction was isolated from the rabbit small intestine epithelium by differential centrifugation in isotonic sucrose medium. The fraction was insignificantly contaminated with fragments of other organellae and microvilli. Respiratory control coefficient of such mitochondria constituted 3-5, when malate-glutamate mixture was used as a substrate. Changes in the functional state of mitochondria were accompanied by stereotypical reconstruction of the "orthodox-condensed" configuration. Introduction of crude choleragen into the mitochondria incubation medium failed to induce any changes in the rate of oxygen consumption in states III and IV (after Chance).
Animals↗
[The morphogenesis of the human brain on the 27th-35th day of development with disordered neurulation].
Human embryos with anomalies of brain and spinal cord were studied on 27-35th day of the development. It was established that developmental anomalies were associated with the disturbed formation of neural tube. The reconstruction of three-dimensional brain arrangement of embryos has shown the presence of different variants of nonclosed medullar tori. In mild disturbance of neurulation, there is an acceleration of organogenesis and morphological differentiation induced by the shackening of normal mechanical tensions and relaxation of neuroepithelial layers. In presence of substantial parts of open neural tube, the development of brain and ectodermal derivatives becomes disturbed to be a possible cause of anencephaly and hypotelorism. The type of disturbed neurulation inducing developmental anomalies of nervous system is suggested to be a factor which determines forms of secondary craniofacial and cranial pathology.
Abortion, Spontaneous↗
[An immunohistochemical study of the primordium and primary differentiation of the parafollicular cells in the human thyroid].
Formation and differentiation of calcitonin-secreting cells has been studied in human embryos. The cells form from the entodermal part of the rudiment of the last pharyngeal cavity. They do not secrete calcitonin before incorporation into the thyroid gland. The first calcitonin-secreting cells appear in the thyroid gland as a diffuse net. The properties and origin of this net have been described.
Antibodies, Monoclonal↗
[Cation permeability of liver mitochondrial membranes during Ca+-dependent anoxic damage in vitro].
Ca2+ ions are responsible for impairment of oxidative phosphorylation in rat liver mitochondria under anoxia in vitro. The decrease in this function is due to inhibition of electron transport over respiratory chain and to uncoupling. The increase in membrane permeability for H+, K+ and Na+ was observed on incubation of mitochondria under anoxic condition together with Ca2+. Uncoupling of phosphorylation depends on the increased permeability of the membranes for H+. The increased permeability of membranes for Na+ and K+ under energy liberation and in presence of penetrating anions led to active swelling of organelles and to secondary (osmotic) impairment. Ca2+-activated mitochondrial phospholipase A2 appears to participate in the organelle impairment under anoxia.
Animals↗
[Cytological characteristics, elemental composition of alveolar macrophages from bronchoalveolar lavage, lung pathology in liquidators of the consequences of the accident at the Chernobyl power plant].
Bronchoalveolar lavage fluid (BALF), broncho- and transbronchial biopsies were examined in Chernobyl wreckers eleven years after the accident. Cytologically and electron-microscopically, there was predominance of alveolar macrophages (AM) with many cytoplasmic foreign bodies containing clear needle-like crystals. Roentgenospectral analysis and laser mass-spectrometry revealed chemical elements which are part of non-active "hot particles" (Al, Si, Ca, Fe) as well as reactor fuel elements and the station constructive materials which are the active part of "hot particles". Programmed BALF allowed to decrease cytosis and the amount of AM containing foreign-body particles as well as concentration of the majority of chemical elements in AM.
Adult↗