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PubMed1980

[Changes in acetylcholinesterase and ATPase activity and certain structural features of the erythrocyte membrane in experimental myocardial ischemia].

Acute heart ischemia induced by ligation of the left coronary artery is associated with variation in the activity of acetylcholinesterase, Na, K-ATPase and Ca, Mg-ATPase in rat erythrocytes. The maximum pronounced variations in the enzymatic activity and in the membrane capacity of erythroblasts for binding direct turquoise are recorded on the 7th day of the experimental myocardial infarction.

Acetylcholinesterase↗
PubMed1981

Multiple structural features are responsible for the nuclease sensitivity of the active ovalbumin gene.

The ovalbumin gene in chick oviduct nuclei or nucleosomes is digested preferentially by either DNase I or staphylococcal nuclease. Staphylococcal nuclease preferentially cuts between and within core particles of the oviduct ovalbumin gene; thus, the ovalbumin gene is more quickly degraded to mononucleosomes and the DNA within these monomers is digested to a nonhybridizable size significantly faster than the chicken globin gene. Mono- and oligonucleosomes generated by partial staphylococcal nuclease digestion at 0 degrees C, but not at 37 degrees C, retain equal sensitivity to DNase I. Most of this sensitivity persists when histone H1 and most of the non-histone chromosomal proteins are removed with 0.6 M NaCl. On the basis of these observations, we propose that nuclease sensitivity of the oviduct ovalbumin gene is due to covalent modifications of the core histones and that this sensitivity is amplified by interaction of other chromosomal proteins with these modified histones.

Animals↗
PubMed1982

Structural features of the cell surface receptor for transferrin that is recognized by the monoclonal antibody OKT9.

The monoclonal antibody OKT9 reacts specifically with the receptors for transferrin on human cells (Sutherland, D. R., Delia, D., Schneider, C., Newman, R. A., Kemshead, J., and Greaves, M. F. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 4515-4519; in Leukemia Markers (Knapp, W., ed) pp. 157-160, Academic Press, New York) and has been used to isolate and characterize this receptor. The receptor is a dimeric glycoprotein (Mr = 180,000) composed of two subunits (Mr = 90,000) and has a pI of approximately 5.2. The transferrin receptor appears to be a transmembrane molecule and is phosphorylated, the phosphate group being predominantly on serine residues. The cell surface form of the molecular possesses both complex and high mannose oligosaccharide chains, which do not appear to have a direct role in antibody (OKT9) binding. The molecule can be cleaved into a Mr = 70,000 fragment from the cell surface, suggesting that the major part of the receptor is exposed to the extracellular environment. The released Mr = 70,000 fragments are not disulfide-linked and possess the antibody (OKT9)- and transferrin-binding sites. Cross-linking studies using radiolabeled transferrin suggest that two molecules of transferrin are bound to each Mr = 180,000 receptor dimer.

Antibodies, Monoclonal↗
PubMed1982

Structural features of a specialized region of the epididymis of the Siberian hamster (Phodopus sungorus).

Light and electron microscopic observations of zone six of the Siberian hamster (Phodopus sungorus) epididymis reveal that two distinct tubule populations exist in this region. The population of smaller tubules apparently arises as diverticula of the larger ducts but, though contiguous, the contents of each remain different and separate. While the larger tubules are laden with sperm and seminal fluid, the smaller ones area filled with degenerating cells and cellular debris. Cytologically, the features of the two tubule types are similar. Both display a prominent Golgi apparatus, substantial amounts of rough endoplasmic reticulum, an extensive population of various lysosomal forms and scattered crystalline inclusions.

Animals↗
PubMed1980

Fine structural features of secretion in adenomas of human pituitary gland.

Ultrastructural investigation of 274 human pituitary adenomas and 39 nontumorous adenohypophyses revealed two distinct types of secretion. Exocytosis was characteristic of prolactin cell adenomas, mixed growth hormone-prolactin cell adenomas, acidophil stem cell adenomas, and nontumorous prolactin cells. The second type, termed "transmembrane effusion," was noted in corticotroph, thyrotroph, gonadotroph, undifferentiated cell adenomas, and oncocytomas, as well as nontumorous corticotrophs, thyrotrophs, and gonadotrophs. It differed from that of prolactin cells and resembled diacrine secretion of gastrointestinal gastrin cells and membrane release in the neurohypophysis. In adenomatous and nontumorous growth hormone cells, neither exocytosis nor transmembrane effusion were apparent, hence a third type of release is suggested. Electron microscopic study of release mechanisms is helpful in the differential diagnosis of pituitary adenomas, since discharge of secretory products is not identical in the various tumor types.

Adenoma↗
PubMed1982

[Structural features of the excretory ducts of the palatal salivary glands in the rat].

In serial semithin sections, by means of a transmission and scanning electron microscopy, perforating holes, through which fluid is transported from the interstitium into the ductal lumens, have been revealed in the deferent duct walls of the palatal salivary glands. The mechanism of how these holes are formed is closely connected with secretory process of glandulocytes and is directly dependent on its intensity. The transmural holes increase porosity of the deferent duct walls, thus they contribute to better moistening of the mouth cavity with fluid both under normal and experimental conditions. Their role is especially important when there is a functional insufficiency of the large salivary glands. There are holes not only in the palatal deferent ducts, but also in other small salivary glands of the mouth cavity.

Animals↗
PubMed1982

[Structural features of obstetric abnormalities of pregnant, parturient and puerperal women during perinatal period, evaluated from a viewpoint of main component (author's transl)].

With an aim to analyze abnormalities of women with high risk pregnancy, labor and puerperium during perinatal period, main component analysis was carried out for 860 perinatal women, using each of six groups (large items) of 29 kinds of their abnormalities (small items) as variables and the following results were obtained. 1) Three main components were extracted and their cumulative communarity was 61.9 per cent. 2) Each of the main component was evaluated using the large items themselves and correlation between the large items and the small ones. The first main component was considered to be related to disturbance of fetal passage through the birth canal, the second to utero-placental dysfunction and obstetric surgery due to other indications than the disturbance of fetal passage through the birth canal, the third to the complications accidental to pregnancy. 3) Main component scores of the three main components were stratified by physical conditions of the newborn infants by the analyzed perinatal women and the correlation between the both were evaluated. Explanation of the first main component was found to be reasonable from its correlation with birth weight, developmental status, hyperbilirubinemia, Apgar score massive aspiration syndrome of the newborn infants.

Birth Weight↗
PubMed1981

Clinical and structural features of equine enteroliths.

Enteroliths were obtained by laparotomy or necropsy of 11 horses, and a collection of smaller concretions was found on pasture. Following analysis by energy-dispersion x-ray analysis and x-ray diffraction, they were found to consist primarily of ammonium magnesium phosphate. Several minor elements were detected, including titanium in some concretions. From a farm with a history of enterolith obstructions, the well water contained a high proportion of magnesium in relation to the other cations.

Animals↗
PubMed1980

[Structural features, biomechanical properties of the cusps of venous valves and walls of lower extremity veins in humans].

Relative tensility and resistivity of walls of superficial and deep veins were studied on 200 lower extremities in persona at the age of 4--86 years. The ability of valves to resist the retrograde liquor flow was studied on the same veins. The data on the valves "endurance" were compared with the character of their connective tissue framework. Relative lengthening of the venous walls increases up to 30--35 years of age, after that time these indices decrease. The wall resistivity is higher in the deep than in the superficial veins. The ability of the lower extremity valves to resist the retrograde liquor pressure is gradually increasing up to 60 years of age, and afterwards this ability is somewhat decreasing.

Adolescent↗
PubMed1995

[The effect of various structural features in molecules of derivatives of pyrene and its heterocyclic analogs on its mutagenic activity].

The mutagenic potency of five acetyl and acetylamine derivatives of nitropyrene and 15 heterocyclic analogues of pyrene was studied in the strain Salmonella typhimurium TA1538. A significant impact of the electron-withdrawing acetyl group in the para-position on the mutagenic activity of derivatives of nitropyrene was shown. The para position of nitro and amino groups as well as of the amino and carboxyl group was also responsible for the mutagenic activity. A proposal for the existence of several cellular mechanisms of activation of molecules of heterocyclic analogues of pyrene is presented.

Heterocyclic Compounds↗