Search

Total dichloromethane, methanol and water extracts, their fractions as well as volatiles of Carthamus lanatus aerial parts were phytochemically screened and evaluated for antibacterial, antifungal and cytotoxic activity. The H(2)O/MeOH fraction of the CH(2)Cl(2) extract exhibited noticeable antibacterial activity. The same fraction and the volatiles showed significant cytotoxic activity., (Copyright 2002 Elsevier Science B.V.)

The effect of Oxadin (a new Bulgarian antimicrobial chemotherapeutic agent) on some parameters of non-specific immune response was investigated in a rat model of infection. After mimicking natural Yersinia enterocolitica systemic infection the number and functional activity of blood leucocytes and peritoneal macrophages were compared between groups of animals treated with Oxadin before and after infection. A significant immunostimulating effect of Oxadin was found in both experimental groups but was better expressed when administered before Yersinia infection. Bactericidal response of peritoneal macrophages (killing ability) and phagocytic activity of polymorphonuclear leucocytes from animals treated with Oxadin and thereafter infected with Yersinia enterocolitica were significantly activated during the first week of study. These findings correlated with the enhanced number of both types of phagocytic cells and the higher glycolytic activity of peritoneal macrophages.

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.

The pathogenesis and the cell immune response (CIR) of guinea pigs after mixed infection with Y. enterocolitica and L. monocytogenes was investigated. The guinea pigs were infected per os with 1.1 x 10(9) CFU Y. enterocolitica 0:3, (pYV+) and four days later with 1.1 x 10(9) CFU L. monocytogenes 4B. Clinical, paraclinical and morphological findings attending the infectious process were followed in dynamics up to the 28th day post infection (p.i.) with L. monocytogenes. The phagocyting activity of alveolar macrophages (aMa) was suppressed against Y. enterocolitica, in contrast to peritoneal macrophages (pMa) engulfing yersiniae more actively at the end of the study. Moreover, the tendency of augmented entering in both phagocytes of L. monocytogenes cells was well demonstrated, starting at the earlier intervals of examination. Histopathological studies showed a purulent meningoencephalitis and a catarrhal pneumonie, non-reactive micronecroses in the spleen and lymphadenitis catarrhalis in the mesenteric lymph nodes. Analysis of the T-cell immune response (T-CIR) showed maximal values in the spleen lymphocytes after Y. enterocolitica and L. monocytogenes mixed infection. The B-CIR occurred early (at the 7th day p.i.) and was maximal at the 28th day p.i. in blood lymphocytes. The results obtained demonstrated that the mixed infection of guinea pigs with Y. enterocolitica and L. monocytogenes runs has a non lethal, generalized illness with a dominant role of L. monocytogenes cells.

Experimental intramuscular infection of hens with Pseudomonas pseudomallei, strain 2796 (1 x 10(9) CFU from a 24-h culture) was reproduced. Clinical, paraclinical and pathomorphological findings were followed from 1 to 30 days after challenge. Haemagglutinin titre, bacterial dissemination in the viscera, number of leucocytes, alveolar (aMa) and peritoneal (pMa) macrophages and their phagocytic activity in vitro were studied. During the course of infection a leucocytosis as well as an increased haemagglutinin titre (1:256) were established. The number of bacteria per gram tissue in the spleen and liver was highest at 1 day post-infection (p.i.). Melioidose bacteria from egg yolk were isolated at 15 and 30 days p.i. Leucocyte and pMa phagocytic activity was maximal at 3 days p.i. unlike the activity of aMa which increased gradually until the end of the study. Inflammatory-necrotic changes were found in the viscera and brain at 3 and 15 days p.i. The investigation of experimental melioidosis infection in hens showed that they are susceptible to P. pseudomallei and this disease takes a generalized subacute course.

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.

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.

An experimental infection was induced in the European ground squirrel (Citellus citellus) by intraperitoneally injecting of 1 ml. of microbial suspension, containing 1 x 10(9) CFU (colony forming units) of Yersinia pseudotuberculosis, serotypes I and III. The infectious process was dynamically followed up from the 1st up to the 30th day, respectively. Account was rendered to the general condition, the internal body temperature and the mortality rate. The phagocytic activity of alveolar macrophages (aMa) and polymorphonuclear leucocytes (PMNL), isolated from the experimental animals, was also determined, as well as the degree of bacterial dissemination into the viscera and the histomorphological changes that found in the parenchymal organs. These investigations confirm the fact that the bacterial agent has a broad spectrum of alterations in the organism of the host--the European ground squirrel (Citellus citellus) in which the pseudotuberculosis develops as a generalized infection, especially pronounced in the animals that were infected with the serotype III.

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.

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.