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Biomedical subjects

L Rakic

Publications and source records attributed to L Rakic.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Semiquantitative cytochemistry in evaluation of apoptotic capacity in bronchoalveolar lavage of smokers and patients with non-small-cell lung cancer.

Apoptotic capacity of pulmonary tissue to produce or remove apoptotic cells by alveolar macrophages (ALMs) was investigated in three groups: healthy volunteers, smokers and patients with non-small-cell lung cancer (NSCLC). Differential cell counting of bronchoalveolar lavage (BAL) specimens revealed significantly higher percentages of neutrophils and eosinophils and decreased percentage of macrophages in BAL of patients with NSCLC in comparison with nonsmokers and smokers. Proportion of lymphocytes was significantly higher in patients with NSCLC than in smokers. These changes in the BAL cell profile may reflect immunology of the lung in pulmonary malignancies. BAL eosinophils were significantly lower and AMs increased in smokers in comparison with nonsmokers. This result might be understood as a consequence of changed tissue architecture of pulmonary tissue in situ, influenced by smoking. Apoptotic detection in cytocentrifuge preparations of BAL cell suspensions was evaluated by TUNEL method. Subsequent steps, adsorption, internalization and digestion of apoptotic cells by alveolar macrophages (AMs) were estimated by semiquantitative cytochemical scoring and indexing method and correlated with percent of free apoptotic cells. Significant increase of apoptotic capacity of pulmonary tissue in control smokers (289.55+/-50.77) in comparison with that of non-smokers (218.29+/-56.24) could be a consequence of stimulated digestion inside the AMs; decreased apoptotic capacity of pulmonary tissue in NSCLC (150.30+/-40.61; p<0.05), in comparison with non-smokers and smokers is in relation to a reduced phagocytosis of the apoptotic remnants, which might be either the cause or the consequence of the oncogenic process.

Apoptosis↗
PubMedDate not supplied

[Characteristic reaction of early sea urchin embryos to cytostatic analogs of transmitter substances].

Early embryos of Arbacia lixula sea urchin, obtained from eggs pretreated with KYR-12 serotonin analog or A-83 dopamine analog, develop quite normally. At the same time they have a sharply decreased supersensitivity to cytostatic analogs of "prenervous" transmitters; usual sensitivity to this analogs does not change. Besides, both the supersensitivity and the usual sensitivity stop decreasing upon an increase in the density of density of experimental embryos in the incubation medium.

Animals↗
PubMedDate not supplied

[Acetylcholinesterase from the electric organ of the ray Torpedo marmorata].

Studies have been made on substrate specificity of acetylcholinesterase (AChE;EC 3-1-1-7) from the electric organ of the ray T. marmorata with respect of choline and thiocholine esters, as well as on the effect of pH, salts and organophosphorus inhibitors (OPI) on the activity of the enzyme. Acetylcholine (ACh), propionycholine (PrCh) acetyl-beta-methylcholine (MeCh), acetylthiocholine ((ATCh) and propionylthiocholine (PrTCh) were hydrolyzed by the enzyme studied at the following relative rates-100: 28.8: 18.3: 87.2: 18.9 correspondingly. In all the cases, inhibition of the enzyme by high concentrations of the substrate was observed. As compared to other AChE, the enzyme from T. marmorata exhibits the highest affinity to ACh. For all the substrates studied, pH dependence of AChE activity followed the curve with maximum 7.5 for ACh and PrCh, 8.0-8.5 for ATCh and MeCh and 7.5-8.5 for PrTCh. Various salts (MgCl2), KCl, NaCl, NaBr, KI) increased AChE activity, the increase being the highest with MgCl2 (3.3 times) and NaCl (2.5X). Biomolecular rate constants ((k) II) for the interaction of AChE investigated with OPI containing cationic group-methylsulfomethylates, O-ethyl-S-(beta-ethylmercapto) ethylmethylthiophosphonate and O,O-diethyl-S-(beta-ethylmercapto) ethylthiophosphate, as well as methyl iodide O,O-disopropyl-S-(beta-phenylmethylamino) ethylphosphate-were significantly higher as compared with k(II) values for corresponding compounds without the cation. The value of k(II) sharply decreased with the increase in the size of the acyl radicals at phosphorus atom in the molecule of OPI.

Acetylcholine↗
PubMedDate not supplied

[Characteristics of the conditioned motor reactions of unrestrained elasmobranches and teleosts].

In elasmobranch (Scyllium canicula, Galleus canis) and teleost (Migull capitocum) fishes it is possible to form motor food-searching conditioned reflexes to discrimination of light and darkness. Some differences were revealed in ecological and conditioned motor behavioural activities in higher and lower sharks. Elasmobranch and teleost fishes exhibit significant differences in ecological, feeding and conditioned reflex behaviour. Nervous activity in elasmobranchs is characterized by lower and primitive organization as compared to that in teleosts.

Animals↗
PubMedDate not supplied

[The action of tiazofurin on the development of sea urchin embryos and larvae].

The effects of the antitumor drug tiazofurin on development of sea urchins Sphaerechinus granularis, Paracentrotus lividus, Strongylocentrotus intermedius, and Arbacia lixula were studied. When 0.01-200 microM tiazofurin (TAF) was introduced in the incubation medium (artificial sea water) just after fertilization or at the midblastula stage, the development proceeded quite normally until the beginning of gastrulation. But later TAF blocked gastrulation and induced formation of mobile ball-shaped larvae with normal pigment cells but devoid of the nervous system, skeletal spicules and digestive tract. The threshold TAF concentrations varied from 0.05 microM (S. granularis) to 2-5 microM (all other species). When TAF was introduced during gastrulation and just after gastrulation, the larvae had defective nervous system and skeleton and suppressed expression of gangliosides. The nonhydrolyzable analog of GTP, GTP-gamma-S (5-20 microM), introduced in artificial sea water no later than at the midblastula stage prevented all above mentioned developmental defects.

Adenosine Triphosphate↗