[Pharmacological prevention of fibrosis in dacryosurgery]. / Medikamentoznaya profilaktika fibrotizatsii v dakriokhirurgii.

Chronic inflammatory process in the lacrimal drainage system is the main etiological factor leading to dacryostenosis and consequent obliteration - partial and total nasolacrimal duct obstruction. Prevention of this process is an urgent problem in dacryology. Currently, there is very little research on the development and use of conservative methods for treating dacryostenosis using anti-inflammatory, as well as anti-fibrotic drugs. In this regard, the main method of treating lacrimal drainage obstruction is dacryocystorhinostomy. However, the problem of recurrence after this operation has not been resolved. The causes of recurrence can be cicatricial healing of dacryocystorhinostomy ostium, canalicular obstruction, formation of granulations and synechiae in its area. Surgical methods of recurrence prevention are associated with possible complications, and there is conflicting data on the feasibility of their use. Based on this, the development of pharmacological methods for the prevention of fibrosis in dacryology is promising, among which the antitumor antibiotic Mitomycin C is the most studied. However, there are no specific scientifically substantiated recommendations for the use of this drug, and the data on its effectiveness vary. This has prompted researchers to look for and study alternative anti-fibrotic agents, such as antitumor drugs, glucocorticoids, hyaluronic acid, small molecule, biological, immunological and genetically engineered drugs, as well as nanoparticles. This review presents the current data on the efficacy and prospects of the use of these drugs in dacryology.

Persistence of Rickettsia prowazekii in cotton rat macrophage cultures.

Rickettsia prowazekii is able to multiply and persist for a long time in cotton rat macrophage culture (29-days observation period). Electron microscopic studies showed that the structure of Rickettsiae remained intact at different intervals post-inoculation (p.i.). In the course of persistence Rickettsiae revealed a reduced capacity to infect chick embryos and guinea pigs, however, the infectious agent could be isolated at all stages of persistence of cultured cells such as fibroblasts of the guinea pig embryo, macrophages of intact cotton rats.

Electron microscopic analysis of in vitro interaction of Rickettsia prowazekii with guinea pig macrophages. II. Macrophages from immune animals.

Alike to macrophages from intact animals, reproduction, destruction and formation of spheroplast-like forms were observed in macrophages from immune guinea pigs 2 months post-infection (p.i.) with the virulent Breinl strain of Rickettsia prowazekii. Unlike to the former, immune macrophages revealed phagolysosomes which were larger in size and contained more rickettsiae showing morphologic signs of destruction. Spheroplast-like forms occurred more often and were more numerous than in intact animals. Structures morphologically similar to L-forms of gram-negative bacteria and that of chlamydiae were also detected. After adding immune serum, more intact rickettsiae and spheroplasts were found in phagosomes as well as more phagolysosomes contained rickettsiae and spheroplasts with morphologic signs of destruction. It is suggested that clearance of immune macrophages from rickettsiae is mediated by at least two processes: on one hand by destruction of rod-shaped rickettsiae within phagolysosomes and, on the other hand, by formation and subsequent destruction of spheroplast-like forms within vacuoles, which probably also function as phagolysosomes.

Electron microscopic analysis of in vitro interaction of Rickettsia prowazekii with guinea pig macrophages. I. Macrophages from nonimmune animals.

Monolayer cultures of peritoneal macrophages of intact guinea pigs were infected with Rickettsia prowazekii (strain Breinl) and examined by electron microscopy after 30 min, 4 and 24 hr post-infection (p.i.). Three parallel processes developed in infected macrophages: reproduction of rickettsiae in macrophage cytoplasm, destruction in phagolysosomes and production of spheroplast-like forms. Reproduction of rickettsiae yielded 2 cell types: those with dense and with light cytoplasm; they were located side by side in the microcolony and seemed to have a common capsule-like coat. Relatively small spheroplast-like forms of about 1 micron in size were regularly detected. Addition of immune serum to macrophages increased the number of rickettsiae, both of rod-shaped as well as of spheroplast-like ones located within phagosomes, but elicited no increase in the number of digested pathogen cells.

[Ultrastructural localization of type-specific antigen of legionella pneumophila]. / Ul'trastrukturnaia lokalizatsiia tipospetsificheskogo anigena u Legionella pneumophila.

Cell suspensions of Legionella pneumophila, a virulent Philadelphia I strain, were incubated with rabbit antiserum to type-specific heat-sensitive antigen III having toxic properties with the use of the indirect immunoferritin technique. Antigen III was localized in the outer fibrillar microcapsule-like layer 12-20 mm thick. In the direct immunoperoxidase test antigen III had globular localization on the cell wall surface. The layer described is unlikely to be a true microcapsule, since it does not contain acid mucopolysaccharides and is readily removed from the cell. It is more likely that it forms as a result of antigen III secretion (and, possibly, of other antigens) being more similar to a capsule-like or mucilagenous layer.