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Biomedical subjects

G Baljer

Publications and source records attributed to G Baljer.

72 records · Page 4Linked to original sources

[Radioprotective effectiveness of the paramunity inducer "pind-avi": investigation using the model "protective tetanic vaccination in mice" after exposure to X-rays (author's transl)].

The model "protective tetanic vaccination in mice" was used in order to try whether the paramunity inducer Pind-Avi may diminish or suspend radiation-induced immunosuppression. The radioprotective effect was ascertained from the different results of immunization in mice exposed to radiation after pretreatment with either Pind-Avi or placebo. The dose delivered amounted to 300 R. Tetanus toxoid was used for immunization. Effectiveness of the tetanic vaccination was analysed by means of load tests with 10 LD50 tetanus toxin, and of antibody determination with passive hemagglutination. Evidence was shown of significant radiation protection following subcutaneous application of Pind-Avi once a day during three days before of after exposure. Efficiency in mice treated with Pind-Avi amounted to 75% (pre-irradiation treatment) and to 43% (postirradiation treatment), whereas the efficiency in controls was zero in all cases. Thus, it was possible with Pind-Avi to suspend radiation-induced immunosuppression within a period of 3 days before or after radiation exposure, not only by means of prophylactic but also by therapeutic administration.

Animals↗

[Nonspecific prophylaxis and therapy of Pseudomonas aeruginosa wound-infections with paramunization using a mouse-model (author's transl)].

The effectiveness of paramunization as a antigen nonspecific method to activate mechanisms against wound-infections due to Pseudomonas aeruginosa was studied using a model of direct infection of mice with a "mice-pathogenic" Ps. aeruginosa strain on artificially set wounds. Active paramunization by means of a biological inducer "PIND-AVI" (M-HP 438) significantly reduced the mortality rate between treated and placebo animals. The best results were obtained by parenteral prophylactic application. A four times repeated injection of PIND-AVI before the wound-infection reduced the mortality rate from 80% (placebo animals) to 26.6%. Almost equally good results were obtained by clinically useful therapeutic application of the preparation. A four times repeated treatment of the mice after wound infection lead to a decrease of mortality rates from 86.6% to 36.6%. The paramunization inducer PIND-AVI caused no side effect in any of the experiments. The mode of inducer action in Pseudomonas aeruginosa wound infections appears to be complex. Increased phagocytosis by nonspecific opsonisation, increased macrophage activity and concurrent stimulation of the lymphopoetic system could possible occur. On the other hand the nonspecific action of mediators could also play a role due to the inducer stimulated T-cells and cellular antigens of Pseudomonas aeruginosa. However both mechanisms in cooperation with specific and nonspecific humoral factors are probably interacting together. To what extent a simultaneous synthesis resp. release of endogeneous interferon plays a role is not known.

Administration, Intranasal↗

[Investigations on combined injuries, 26th communication: investigations on the changes in the state of resistance following sublethal whole-body irradiation (author's transl)].

The risk of a bacterial invasion by pseudomonas, e. coli, proteus, citrobacter and gaffkya via an open skin wound was investigated in combined injured mice (infliction of a skin wound and irradiations). Suspensions of different bacterial strains were applied on the wound and then the lethality was determined. Besides of apathogenic (citrobacter, proteus, gaffkya) and high pathogenic bacteria (e. coli and pseudomonas) an e. coli strain of the 0-Group 81 was found that seems to induce a decrease of lethality even after sublethal whole body irradiation.

Animals↗

Controlled field trials with oral and nasal immunization against tetanus in humans.

Under field conditions, the comparative effectiveness of oral, nasal and intramuscular vaccination of humans with tetanus toxoid was investigated. The effectiveness was tested by the determination of antitoxin titers with the L+-method. Oral booster vaccination produced only very low and irregular increases in antitoxin titer even at the highest dose of 6,000 Lf toxoid. In the most favourable case following triple oral immunization, a rise from 6.2 to 6.6 I.U. was achieved. Primary oral vaccination failed to stimulate measurable antitoxin production. After nasal booster vaccination with 1,000 Lf toxoid, a ten-fold rise in antitoxin titer was detectable. Following primary nasal vaccination, an average neutralization titer of 1 I.U. was achieved. The results of intramuscular and nasal booster vaccinations were similar although the antitoxin titers were significantly higher after primary intramuscular vaccination than after primary nasal vaccination. The average antitoxin titer amounted to 11.6 I.U. These results indicate that primary and booster vaccination against tetanus by the nasal route is a safe and effective procedure.

Administration, Intranasal↗

[Experimental investigations on the immunity development in irradiated mice after local and parenteral immunization with tetanus-toxoid (author's transl)].

Using the "tetanus-mouse" model the differences in immunity development between animals exposed to irradiation (300 R and 400 R) and animals not exposed to irradiation after nasal and subcutaneous vaccination was investigated. Immunization was carried out 1, 3, 6 and 10 days before and after exposure to irradiation. Efficacy of immunization was tested by challenge with 10 X LD50 tetanus-toxin and by antitoxin determination with L+-method. The degree of the immune response was dependent on 1. the irradiation dose, 2. the interval between active immunization and the ensuing or preceding irradiation, 3. the mode of vaccination (local or parenteral) and 4. the vaccination dose.

Animals↗

[A new possibility of "non-parenteral" (local) vaccination: immunization per wound (author's transl)].

Hitherto the term "non-parenteral" (local) vaccination meant all those modes of vaccination where the vaccine is applied on the skin or the mucous membranes. The most common types of local immunization are oral and nasal vaccination. Using model studies with the mouse immunization per wound was investigated as an alternative mode of vaccination. Immunization was done with tetanus-toxoid, efficiency was tested by challenge with 10 LD50 tetanus toxin. For immunization per wound only slightly higher antigen doses are necessary compared with subcutaneous immunization. A single subcutaneous vaccination with 2 Lf tetanus-toxoid and a single application per wound of 10 Lf resulted in the same efficiency index of 100. Immunization per wound has to be carried out immediately after injury. It seems to be optimal within the first 3 to 5 hours. At a later time the same efficiency index can only be achieved by use of a higher antigen doses. Immunization per wound is possible with all kinds of wound, even with burns. Size of wound and wound-supply do not influence the efficacy of wound-immunization. Immunization per wound does not disturb wound healing. The experiments reported here showed, for the first time, that immunization per wound is as effective as parenteral immunization. The most important advantage of wound-immunization is the speed and ease with which it can be administered, a fact which predestines it for vaccination in emergency cases. In practice it will be useful to combine wound-vaccination with wound-sprays.

Administration, Topical↗

Oral immunization against tetanus.

Model experiments in mice were used for the investigation of oral immunization against tetanus. The efficacy of oral tetanus toxoid application was tested by subcutaneous challenge (10 LD50 tetanus toxin) and antitoxin determination by L+-method. Reasonable protection could only be achieved when toxoid was in intensive contact with the mucous membranes of the oral cavity, whereas immunization by way of the gastrointestinal tract failed completely. After a single oral vaccination with 200 Lf fluid tetanus toxoid onto mucous membranes of the oral cavity the efficiency index was 75. A 100% protection was obtained in challenge after 3 applications of 200 Lf toxoid. In comparison, a single subcutaneous dose of 2 Lf tetanus toxoid resulted in an efficiency index of 100 and a single intranasal immunization with 100 Lf in an efficiency index of 93. Development of immunity after oral immunization was much accelerated if compared with parenteral immunization. 20% of the orally treated animals were immune 5 days after vaccination. After the same period subcutaneously treated animals had failed to develop any protection at all. Antitoxin titers after one oral vaccination (200 Lf) were similar to the ones after one subcutaneous dose (2 Lf). A distinct increase in antitoxin titers could only be observed when revaccination was done subcutaneously. The results obtained with mice apply analogically to guinea pigs.

Administration, Intranasal↗

[Experimental investigations on oral immunization with tetanus-toxoid (author's transl)].

Model-experiments in mice were used for the investigation of oral immunization with tetanus-toxoid. The efficacy of oral toxoid application was tested by challenge and anti-toxin determination. The oral immunization with tetanus-toxoid induced only a sufficient protection, when toxoid was in intensive contact with the mucous membranes of the oral cavity. Local immunization via gastro-intestinal-tract failed. After a single vaccination with 200 Lf tetanus-toxoid onto mucous membranes of the oral cavity the efficiency index was 75. In comparison, a single subcutaneous application of 2 Lf tetanus-toxoid resulted in an efficiency index of 100 and a single intranasal immunization of 100 Lf in an efficiency index of 93. So the application of toxoid subcutaneously or onto nasal mucous membranes induced higher protection than oral application. Temporary development of immunity after immunization via the mucous membranes of the oral cavity was much better than parenteral immunization. 20 per cent of orally immunized animals were immune 5 days p. vacc. At the same time subcutaneously immunized animals failed to develop any protection. The efficiency rates obtained in challenge correlate with antitoxin content in the serum.

Administration, Oral↗

Sequence polymorphism of the Salmonella plasmid virulence factor D (SpvD) in Salmonella enterica isolates of animal origin.

The nucleotide sequence encoding the Salmonella plasmid virulence factor D (SpvD) was determined in 17 Salmonella strains that were different in O and H antigen patterns, animal host and geographical origin, and year of isolation. Nucleotide sequence comparison revealed the existence of at least nine spvD alleles resulting in 8 SpvD protein variants although the nucleotide sequences were highly similar (identity 98.8-100%). The spvD gene products differed from each other in up to 4 amino acid residues only with the exception of the carboxy-terminally truncated SpvD variant of one S. Gallinarum field isolate. The highly conserved primary structure of SpvD in epidemiologically relevant salmonellae suggests that this virulence factor is a promising antigen candidate for diagnostic purposes (i.e. antibody detection in infected animals) but also for immunoprophylaxis in farm animal species.

ADP Ribose Transferases↗