Interferon type I in protective body reactions in an experimental Klebsiella infection]

The study on mice with experimental generalized Klebsiella infection, carried out with the use of microbiologic, immunologic and pathomorphologic methods, revealed that the intraperitoneal injection of type I interferon into the animals prevented their death and led to the rapid elimination of the infective agent from their body, enhanced the phagocytic and metabolic activity of polymorphonuclear lymphocytes of their peritoneal exudate, decreased the manifestation of microcirculatory and dystrophic changes in the parenchyma of their internal organs.     

The efficacy of Klebsiella pneumoniae bacteriophage in the therapy of experimental Klebsiella infection

The effectiveness of specific phage therapy was studied on Klebsiella experimental sepsis in noninbred white mice, caused by the intraperitoneal injection of K. pneumoniae highly virulent strain K2 5055 into the animals. For treatment, Klebsiella polyvalent bacteriophage administered on day 2 after the infection of the animals with Klebsiella was used. The study revealed that bacteriophage could be detected in the blood and internal organs of the animals within 24 hours irrespective of the route of its administration: intraperitoneal, intravenous or intranasal. The bacteriophage preparation, introduced intraperitoneally, was shown to be effective in the treatment of generalized Klebsiella infection. One daily intraperitoneal injection of Klebsiella bacteriophage for 15-20 days proved to be the optimum scheme of treatment. In contrast to chemotherapeutic preparations, bacteriophages had no effect on normal microflora and did not aggravate dysbiotic disturbances. For this reason, bacteriophages may become one of alternative antimicrobial remedies, selectively affecting infective agents.     

Antiviral activity of oral ultralow doses of antibodies to gamma-interferon: experimental study of influenza infection in mice]

Course intragastric administration of ultralow doses of human gamma-interferon antibodies (ULD anti-IFN-gamma) to intact mice resulted in an increase of endogenous IFN-gamma production by the animal lymphocytes. Oral prophylactic administration of ULD anti-IFN-gamma significantly lowered the influenza virus concentration in the animal lungs at the initial stage of the aerogenous infection: in 2 (p = 0.05) and 3 (p = 0.07) days after the contamination. The therapeutic antiviral effect of ULD anti-IFN-gamma in mice with influenza was evident from a significant decrease of the influenza virus concentration in the lungs of the animals on the 4th (p = 0.05) and 5th (p = 0.07) days after the contamination. The antiviral effect of ULD anti-IFN-gamma after the prophylactic and therapeutic use is likely provided by induction of endogenous IFN-gamma.     

The microbiological and pathomorphological characteristics of Klebsiella infection]

Biological properties of 350 strains of Klebsiella pneumoniae isolated in newborns during the outbreak of intrahospital infection have been studied. Experimental infection with isolated strains of a similar plasmid profile is simulated, interrelation between the presence of plasmids and ability of the strain to induce generalized Klebsiella infection is shown. Pathological processes in the newborns with generalized infection and in animals with the reproduced experimental Klebsiella infection are shown to be similar in principle.     

Multifactor study of combined effects of an antibiotic and polysaccharide in experimental infection]

Multifactorial analysis was applied to the study of the combined effect of doxycycline and a polysaccharide of microbial origin in experimental plague infection. A marked synergistic action of the antibiotic and polysaccharide used in subtherapeutic doses in treatment of the infection was observed. By the results of the experiments polynomial statistic models of the 2nd order were designed and nomographs or equal level lines were plotted. The models and nomographs described the animal survival rate and lifespan within a wide range of the control parameters. The dose/time regimens for the use of the polysaccharide combination with doxycycline were optimized on the basis of the multifactorial analysis.     

Effectiveness of cefotaxime in experimental plague infection]

Cefotaxime was shown highly efficient in prophylaxis and treatment of experimental plague infection in albino mice. The in vitro activity of cefotaxime against natural strains of the plague microbe was 32 to 64 times higher than that of cefazolin, cephalothin and cefmetazole. The combined use of cefotaxime with amikacin significantly increased the percentage of the survived albino mice with plague infection as compared to the use of the antibiotics alone.     

Rifampicin effectiveness in experimental anaerobic gas infection]

The inhibitory effect of rifampicin against most of 82 strains of pathogenic Clostridia was evident at a concentration of less than 0.1 gamma/ml. The bactericidal concentrations were close to the bacteriostatic ones with respect to 74 strains. The protective effect of rifampicin in mice with experimental anaerobic gaseous infaction caused by different species of pathogenic Clostridia was evident at doses of 0.5 mg/kg. In infections caused by associations of Clostridia and Staph. aureus resistant to other antibiotics, rifampicin was effective, while ampicillin had no protective effect. Rifampicin administered 24 to 96 hours before the infection prevented the specific process. A number of other antibiotics, such as ampicillin, cephaloridin, morphocycline and 7-chlor-7-desoxylincomycin had no such a capacity. The prolonged prophylactic effect of rifampicin was associated with maintenance of low antibiotic levels in the blood and muscle tissues which were higher than the minimum inhibitory concentrations. The effect of rifampicin against the background of a rapidly developing process was less pronounced and limited in time.     

Formation of secretory antibodies in experimental influenza infection]

The principal peculiarities attending formation of specific secretory immunity in experimental influenza infection were marked individual variability and a relative autonomicity of accumulation of the secretory antibodies. Functional condition of the secretory immunity before the infection influenced the formation of antibodies in the secretions and the blood sera: when the concentration of the secretory antibodies before the infection constituted 1 : 8--1 : 16, general and secretory antibodies accumulated less intensively. There was a progressive fall of the concentration of the secretory immunoglobulin A in the majority of the volunteers the first 3 weeks after the infection. It is supposed that this process played a significant role in the pathogenesis of influenza complications.     

Protection of rats against pseudorabies virus infection by gamma-interferon

Administration of recombinant rat gamma-interferon to rats conferred complete protection against an otherwise lethal intraperitoneal pseudorabies virus (PRV) infection. The primary target cell of the virus has been identified as the serosal cell of the peritoneum. Histologic examination showed that after infection of the underlying adventitia, the virus replicates in the myenteric and submucosal plexuses of the gastrointestinal tract; this is followed by centripetal spread to the autonomous and central nervous system. In recombinant rat gamma-interferon-treated rats, viral antigen was absent in the primary target cells and was not detected in any other organ. In interferon-treated cultures of peritoneal fibroblasts, which represent another primary target cell population in vivo, complete inhibition of PRV replication was observed. The peritoneal macrophage is not susceptible to PRV, as was shown by coculture and immunocytochemical studies. Peritoneal cells from gamma-interferon-treated rats showed enhanced major histocompatibility class II antigen expression and extrinsic antiviral activity in PRV-susceptible rat embryo fibroblasts. The results presented in this study indicate that protection by the lymphokine is likely to be based on direct inhibition of viral replication in serosal cells.     

Submicroscopic features of cecal cells in experimental Escherichia infection]

Ultrastructural changes of the caecum cells were studied for the period from 15 minutes to 2 weeks after inoculation using the model of experimental escherichiosis. Evolution processes in relation to different caecum cell populations were followed up submicroscopically. Ultrastructural changes observed evidence derangement of protein and water-salt cell metabolism, immune trends of experimental escherichiosis.     

Efficacy of therapeutic and prophylactic actions of ultralow doses of antibodies to gamma-interferon in experimental murine model of herpes virus]

The process of the disease due to herpes simplex virus types 1 and 2 (HSV-1 and 2) was studied on white uninbred mice weighing 10 to 12 g. The animals were infected intracerebrally or intraperitoneally. Intraperitoneal contamination of the animals with MS strain of HSV-2 was used for the experimental model of the herpes simplex infection. The prophylactic antiherpes action of ultralow doses of the human gamma-interferon antibodies (ULD of anti-IFN-gamma) at a course of its intragastral administration was evaluated. The preparation was shown to have a significant (p < 0.05) protective effect in a dose of 10 LD50, evident from a 10-fold decrease of the HSV-2 accumulation in the brain, a lower percentage of the animal deaths and an increase of the average lifespan of the animals by 3.3 days. The study of the therapeutic action of ULD of anti-IFN-gamma at a course of its intragastral administration showed that the preparation had no significant positive effect on the disease process in the animals infected with HSV-2 in a dose of 10 LD50. However, a positive effect associated with delayed virus replication in the brain was observed in the study on the therapeutic effect of ULD of anti-IFN-gamma after its intragastral administration to the mice infected with a sublethal dose of the virus.     

The astrocyte reaction to an experimental herpes infection]

The experimental research carried out on rabbits was aimed at determination of astrocytes reaction during brain inflammation caused by Herpes simplex virus. The study was made with the help of glia marker. Immunocytochemical findings showed that the earliest structural brain responses to the infection were changes in astrocyte glia. This was evident from the swelling and hypertrophy of vessel crus and from increased number of astrocytes around the vessels. Glia complexes (astrocyte agglomeration) were formed in the affected sites. During the exudative reaction the hyperplastic alterations of astrocytes were not observed. Later the injured spots of brain tissue were replaced by proliferating astrocytes. The conducted investigation has shown the astrocyte glia to be different during different stages of the infectious process. One may suppose that different subtypes of astrocytes response has place during each stage which should be further confirmed. One may also suppose that a similar alterations of astrocytes coincide with interferon and interleukin secretion by these cells. This is suggested to be a structural base of immune response of the brain.     

Antibacterial activity of zearalenone]

Zearalenone, a mycotoxin secreted by Fusarium sp. and Gibberella zeae, shows a narrow range of antibacterial activity limited to some Gram-positive aerobic spore-forming bacteria. In Bacillus thuringiensis (Berliner), a highly sensitive species, this activity is characterized by a decrease of cellular division and induction of atypical cells. These effects resemble those obtained with two other mycotoxins which possess a lactone structure: aflatoxin B1 and patulin.     

The pathogenetic bases for chemotherapy in an experimental Salmonella infection]

The effect of etiotropic (polymyxin and adriblastin) and pathogenetic (levamisole and vitamin E) chemotherapy on lipid peroxidation (LPO), phagocyte functional activity and the process and outcomes of Salmonella infection was studied in rabbits. It was shown that development of salmonellosis was accompanied by activation of LPO which was phase-by-phase. There was synchronism in changing of LPO and neutrophilic phagocytic activity. Adriblastin and levamisole stimulated LPO and increased the neutrophilic phagocytic activity. Vitamin E inhibited LPO and had an unfavourable effect on the process and outcomes of the infection. The problem in differential use of the chemotherapeutic drugs with an account of their modulating effect on LPO is discussed.     

Changes in the ultrastructure of staphylococci in kidney tissue in experimental infection]

A study of ultrathin sections fo the kidney tissue of mice infected with staphylococci showed intracellular localization of the bacteria. In vivo there occurred a morphological reconstruction of external layers of the cell wall of staphylococci, and lysis of individual staphylococci. The middle part of the cell wall and the cytoplasmic membrane proved to be the structures the most stable to lysis. Specific changes of bacteria similar to the changes noted with the action of penicillin on staphylococci in vitro followed effective penicillin therapy of mice infected with staphylococci.