Choledocholithiasis after cholecystectomy

Concrements were found in the ducts of 172 patients subjected to secondary surgical interventions on bile ducts. The detailed analysis of the data failed to answer the question whether the stones could be formed immediately in the ducts without such conditions as a mechanical obstacle for the outflow of bile, the presence of foreign bodies and a big stump of the cystic duct. Such a formation of stones can take place in very few cases. The authors have shown that control cholangiography and especially choledochoscopy can reduce the danger to leave the stones in the ducts, but does not eliminate the danger completely. Nevertheless they think that now it is possible to lessen the indications for biliodigestive anastomoses in choledocholithiasis since the retained stones can be revealed within the first days after surgery and, as a rule, removed with instruments or by other methods using the drainage left in the ducts.     

Scale-sensitivity, fractal analysis and simulations

The scale-of-interaction is presented as a criterion for establishing functional correlations. It is also used in simulating interactions with rough surfaces. Fractal analysis by the patchwork method is discussed and is used as the basis for evaluating data acquisition systems. The patchwork method is also used as the basis for simulating interactions with the surface. The essence of the simulation is to understand macroscopic, apparently continuous, interactions as the sum of a large number of discrete interactions at some appropriately fine scale. The simulations shown here use topographic data acquired from engineering surfaces.     

Dental enamel hypoplasia in children with combined congenital and hereditary defects in the development of the CNS and the locomotor system (infantile cerebral palsy, spinal cord hernias and myopathies)]

The incidence of hypoplasia in children with congenital and hereditary developmental defects of the central nervous system and the locomotor system is high (44.5 +/- 3.5%), much higher than the incidence of hypoplasia in children without neurological disorders (2.0 +/- 2.0%). This is explained by exposure of the fetus and newborn to numerous intensive factors complicating the biological anamnesis because of profound disturbances of the metabolic processes and largely responsible for the underlying neurological disease and defects of hard dental tissues presenting as hypoplasia of the enamel.     

Adsorption of haematoporphyrins on the planar bilayer membrane

Adsorption of haematoporphyrin derivatives with different hydrophobicities of peripheral groups on a planar bilayer lipid membrane (BLM) was studied in the dark and upon illumination by the visible light. Haematoporphyrin molecules were shown to adsorb on the BLM as anions. The adsorption changed the boundary potential at the membrane/water interface, in particular, it altered the potential in the diffuse part of the double layer outside the membrane and increased an additional unscreenable potential drop inside it. Illumination decreased the value of the negative potential drop due probably to the appearance of a positive charge in the haematoporphyrin macrocycle. The adsorption of haematoporphyrins affected the BLM conductivity induced by different ionophores, which can be explained by changes in membrane structure. Haematoporphyrin derivatives with higher hydrophobicities adsorbed deeper inside the membrane, caused greater changes in its structure and displayed a stronger photodynamic effect.