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Biomedical subjects

H Najdenski

Publications and source records attributed to H Najdenski.

27 records · Page 2Linked to original sources
PubMed1995

Haematoporphyrin and proflavine-sensitized photoinactivation of Salmonella dublin.

The photosensitive activity of haematoporphyrin (HP) and proflavine (PF) on some biological parameters of Salmonella dublin cells was assessed. The investigations showed a decreased respiratory activity of photosensitized PF bacterial cells, accompanied by lower virulence. HP-treatment and light irradiation of salmonellae did not influence their survival in vitro, which was in contrast to the PF-incubated and irradiated cells. Light irradiation of HP- and PF-treated bacteria did not change their phagocytosis from guinea pig alveolar macrophages. In the presence of visible light the PF-treatment considerably reduced the survival rate and multiplication in alveolar macrophages in comparison with HP-treated and light-exposed bacteria. Correlation was established between the degree of structural damage, as observed by electron microscopy and the level of diminution of the chosen biological parameters, which were more strongly expressed after PF-treatment. PF as a photosensitizer which influences the bacterial genomes and its possible practical use, is discussed.

Animals↗
PubMed1994

Behaviour of Salmonella dublin in mice and rats upon intraperitoneal infection.

The fate of Salmonella dublin in mice and rats after intraperitoneal infection was studied in relation to the bacterial net growth rate in the peritoneal cavity, liver and spleen, and to the corresponding inflammatory cellular response in the peritoneal cavity. Rats showed a better host defence, expressed by a greater cellular inflammatory response followed by suppressed bacterial growth. In contrast, the cellular response of mice to the higher bacterial growth was relatively low. These results may explain some mechanisms of natural resistance to salmonellosis in different hosts.

Animals↗
PubMed1994

Efficient subtyping of pathogenic Yersinia enterocolitica strains by pulsed-field gel electrophoresis.

Yersinia enterocolitica is an enteropathogen that has recently and rapidly expanded over the world. There is a close correlation between the biotypes, serotypes, and phage types of the strains, making it virtually impossible to distinguish isolates of the same serotype with the classical phenotypic markers. In the present study, pulsed-field gel electrophoresis (PFGE) was used to compare the NotI genomic profile (i.e., pulsotype) of 20 strains each of serotypes O:3, O:9, and O:5. Eleven, 12, and 18 different pulsotypes were obtained, respectively, indicating that this technique is very efficient for subtyping pathogenic isolates of Y. enterocolitica. Within strains of serotype O:5, PFGE differentiated two subgroups that corresponded to two biotypes (biotypes 1A and 3). Comparison of the pulsotypes of three strains of biotype 3 and serotype O:3 (referred to as 3/O:3) with those of strains 4/O:3 and 3/O:5 suggested that the pulsotype is closer to the biotype than to the serotype. The pulsotypes of five pairs of strains isolated from the same patient or siblings were also analyzed. In four pairs, the two strains displayed identical pulsotypes, indicating that PFGE might be a powerful epidemiological tool. In the fifth pair, one restriction fragment differed, suggesting that genomic polymorphism may occur in vivo in Y. enterocolitica. Finally, the in vitro genomic stabilities of one strain each of Y. enterocolitica O:3, O:9, and O:5 were investigated. The pulsotypes of 10 isolated colonies were identical within each strain, indicating that in vitro, the genome of Y. enterocolitica is much more stable than that of Y. pestis.

Bacterial Typing Techniques↗
PubMed1994

Dark interaction of haematoporphyrin and proflavine with Salmonella dublin cells.

The influence of haematoporphyrin and proflavine on the virulence, survivability, respiratory activity and cell wall ultrastructure of Salmonella dublin cells was studied. There was a decrease in all biological properties investigated, especially when haematoporphyrin was used for dark incubation in comparison with proflavine. The possible clinical use of negatively charged photosensitizers is discussed.

Animals↗
PubMed1992

Cytometric and cytochemical study of peritoneal and alveolar macrophages from Yersinia pseudotuberculosis infected ground squirrels (Citellus citellus).

The enzymic activity (succinate dehydrogenase, acid and alkaline phosphatase) of alveolar and peritoneal macrophages as well as leucocytic reaction of ground squirrels infected with Yersinia pseudotuberculosis (I and III serovar) have been investigated in dynamics from the 1st up to the 30th day. The animals infected with III serovar survived only to the 7th day, while those infected with I serovar survived up to the 30th day after inoculation. A massive influx of leucocytes having peak values (100-fold increase) on the 3rd day after infection has been found in the peritoneal cavity of the animals infected with I serovar. Moderate leucocytosis in the blood, and insignificant fluctuations in alveolar macrophage number have been established too. An earlier and higher activation of succinate dehydrogenase in alveolar and peritoneal macrophages from animals infected with III serovar in comparison with those infected with I serovar was observed. No differences in alkaline phosphatase activity of alveolar and peritoneal macrophages have been found between the animals infected with I and III serovar. A correlation has been found between the number of leucocytes and changes in the enzymatic activity of the macrophages. A metabolic transformation was demonstrated typical for different macrophages (peritoneal and alveolar), in the course of this experimental intraperitoneal infection. Obviously, more virulent serovar III of Y. pseudotuberculosis fails to attract leucocytes to the peritoneal cavity sufficiently quickly, so it overcome the local protective mechanisms with consequent systemic cytochemical changes. On the other hand the virulent serovar I attracts leucocytes to the peritoneum and is presumably destroyed by them.

Animals↗
PubMed1992

Cytometric haematological analysis of experimental Yersinia pseudotuberculosis infection at temperatures of cultivation of 25 degrees C and 37 degrees C.

The dynamics of acute lethal infection with Yersinia pseudotuberculosis (serovar III) grown at 25 degrees C and 37 degrees C, respectively, were studied in guinea-pigs. Using an automated hematology analyzer, the quantity and quality of the host cellular response was determined at the primary site of infection (the peritoneal cavity) and in parallel in the blood. A much more intensive leucocytic response of monocytic type was observed in the animals infected with microorganism grown at 37 degrees C. This type of reaction was associated with a lower mortality rate and a relatively benign progression of the infection.

Animals↗
PubMedDate not supplied

Chemical composition and biological activities of the Black Sea algae Polysiphonia denudata (Dillw.) Kutz. and Polysiphonia denudata f. fragilis (Sperk) Woronich.

The two investigated algae had almost identical sterol composition, but there were significant differences in the composition of the polar components and especially in the composition of the volatiles. P. denudata f. fragilis extracts possessed a stronger biological activity (antibacterial, antifungal and toxicity against Artemia salina). Despite the minute morphological differences between the two algae, we recommend P. denudata f. fragilis to be regarded as P. denudata subsp. fragilis.

1-Butanol↗