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Biomedical subjects

T Todorov

Publications and source records attributed to T Todorov.

At least 73 records · Page 4Linked to original sources
PubMed1980

Histoautoradiographic studies of 3H-thymidine labelled Erysipelothrix rhusiopathiae introduced into albino mice.

S-forms of E. rhusiopathiae were cultivated in a 3H-thimidine-containing medium. A suspension washed three times in succession was intravenously injected into albino mice. At certain intervals liver, spleen and kidney were examinated by routine autoradiogrphy. Intact labelled bacteria were found as early as 5 min after administration in the blood capillaries, around cells of the RES and in some nuclei of hepatocytes. Later they are detected in the cytoplasm of micro- and macrophages, around megacaryocytes and in some of their nuclei. After 6 h the labelled population sharply decreases due to a very active reproduction and mortality of the initial population. The localisation of bacteria in liver nuclei and the spreading of S-forms of E. rhusiopathiae in comparison with the avirulent L-forms therefrom are discussed.

Animals↗
PubMed1979

Immunoreactivity in pulmonary echinococcosis. A comparative study of immunodiagnostic tests.

A comparison was made of the diagnostic value of five immunological tests-complement fixation (CF), latex agglutination (LA), bentonite flocculation (BF), passive haemagglutination (PHA), and intradermal (ID)-in patients operated on for pulmonary echinococcosis. The sensitivity of all five tests was significantly lower in the patients with pulmonary echinococcosis than in a comparable group with liver echinococcosis. Some 252 patients with miscellaneous nonhydatid diseases and parasitic infections were also tested; nonspecific reactions were highest in the ID and CF tests and lowest in the LA and BF tests. None of the serological tests was significantly more sensitive than the others, although the CF test was somewhat less sensitive and therefore probably has the least diagnostic value in pulmonary echinococcosis. The ID test showed a significantly higher sensitivity than any of the serological tests. The difficulties encountered in the immunodiagnosis of pulmonary hydatid disease are discussed and it is recommended that at least two serological methods (PHA and either LA or BF) and the ID test should be used in each case.

Echinococcosis, Pulmonary↗
PubMed1979

Immunoreactivity in pulmonary echinococcosis. 2. Evaluation of antibody response.

The part played by certain factors in determining the antibody response in pulmonary echinococcosis has been studied. Five immunodiagnostic procedures were used-complement fixation, latex agglutination, bentonite flocculation, passive haemagglutination, and intradermal tests-and parasitological and pathological examinations were carried out. The number of hydatid cysts had only a small influence on the qualitative nature of the immune response while the quantitative effect was considerable. The immune response did not vary significantly in relation to the size of hydatid cysts but it was affected by changes within the cysts and the surrounding lung tissue. In patients with cysts full of clear hydatid fluid the proportions with negative results and relatively low antibody titres were highest. In these patients the size of hydatid cyst appeared to be significant-the smaller the size, the lower the antibody level. The immune response is weak or completely absent when the hydatid cyst has a thick fibrous capsule. When suppurative changes are present in the hydatid fluid and/or in the fibrous capsule, and when there is inflammatory involvement of the surrounding lung tissue an easily detectable immune response may be seen at an early stage, sometimes even with a high antibody level, but later it usually decreases and may disappear completely. A hypothesis for the explanation of immunological reactivity in pulmonary hydatid disease is discussed.

Antibodies↗
PubMed1979

Circulating antibodies in human echinococcosis before and after surgical treatment.

Antibody levels in 89 patients who had been operated on for hydatid disease were studied over a period of 4 years by complement fixation, latex agglutination, bentonite flocculation, and passive haemagglutination tests. The geometric mean titres were much higher in patients with liver echinococcosis than in those whose lungs were affected. In the first month after operation, an increase in antibody level was observed more often in the former than in the latter. The raised level usually persisted for 3-6 months.In one group of 77 patients, the serological tests either became negative 6 months to 2 years after operation or remained positive during the entire postoperative period. In the other 12 patients, who had recurrent echinococcosis, the tests did not become negative, although there was a reduction in antibody levels during the first and second postoperative years in 6 patients, followed by a rise when the disease recurred. Antibody levels remained high during the entire observation period in the other 6 patients.The prognosis can be considered favourable in patients with low pre-operative titres, or negative tests, provided the tests remain negative up to the end of the first year after operation or become negative within one and a half years. Where there is only a small reduction in antibody titre, the prognosis may still be favourable if the decrease continues to fall up to the end of the second year. Since a drop in antibody titres occurred in certain cases with recurrent infection, it is advisable to defer an opinion on the prognosis until the end of the second year. If the fall in antibody titres is followed by a steady rise, or if they remain high or show slight fluctuations, a recurrence is almost certain.

Antibodies↗
PubMed1979

[Demonstration of Precipitating antibodies in patients with echinococcosis using a counter immunoelectrophoresis (author's transl)].

A counter immunoelectrophoresis was used for the demonstration of antibodies to echinococci. The antigen was prepared from hydatid fluid obtained from liver cysts of sheep. After concentration the antigenic material contained 1800 to 2900 micrograms of nitrogen per milliliter fluid. One or more precipitating lines were regarded as positive. Serum samples of 184 patients with surgically proven echinococcosis gave positive results in 80,4% of the cases. Among them, patients with hydatid disease of the liver were positive in 83,2% of the cases, and patients with hydatid disease of the lung were positive in 78,6 of the cases. The arithmetric mean of the number of lines was 2,4. Sera of 1182 patients with other diseases (among others diseases of the gastro-intestinal and respiratory tract, allergies, neuro-psychiatric, gynecologic and parasitic diseases) reached in 4,6% of the cases with the formation of precipitating lines. The described test is simple to perform, it can be read after a short period of time and it can be used as a screening test for mass case finding.

Antibodies↗
PubMed1978

Effect of experimentally induced trichinellosis on the infection with Erysipelothrix rhusiopathiae in rats.

Infection with Erysipelothrix rhusiopathiae in rats infested 20 days earlier with Trichinella spiralis developed more slowly, the clinical and pathoanatomic changes in the joints were expressed to a less extend, and the mortality rate was lower. The erythrocyte sedimentation rate, the precipitin formation and the phagocytic activity of the macrophages did not considerably change. Experiments carried out to elucidate this fact did not reveal any antigenic or antagonistic relationships between parasite and bacterium nor any protective effect of the host's serum. The inhibitory influence of corticosteroids on the defence forces was not completely manifested in the rats infested. This fact might be explained by interrelations depending both on the cycle of helminth development and on the non-specific immunological reactivity of the organism, the latter being stimulated by the helminth invasion.

Adrenocorticotropic Hormone↗
PubMed1978

[Elimination of multiple drug resistance of intestinal bacteria in white mice in vivo with proflavine and rimactan].

Albino mice, infected with 0.4 cu. cm of 10(10) microbial cells (S. Heidelberg), were treated with proflavin (0.4 cu. cm of a 0.3% solution) and rimactan rifamycin SV (0.4 cu. cm of a 0.4% solution). Proflavin was given singly and four times, daily, in the course of four days, and rimactan was applied four times. Given in a single dose proflavin was found to prolong twice as long the life span of albino mice infected with S. heidelberg. When injected four times it lowered considerably the mortality rate among the animals, the percent of survivals being 62. It was shown to hinder the transmission of multidrug resistance to the normally existing intestinal microflora. It also eliminated the multidrug resistance that intestinal bacteria had acquired in the course of the first several days of drug application. The action of rifamycin proved stronger: 83% of the albino mice treated survived. It eliminated the markers of resistance--both the acquired ones and those carried by the normal recipients (intestinal bacteria)--that substantiated multidrug resistance as well as some of the markers of the donor itself (S. heidelberg).

Acridines↗
PubMed1978

[Production of live attenuated vaccine against colibacillosis in pigs].

Two strains of beta-hemolytic Escherichia coli, p-0141 and i-0149 were used to obtain mutant E. coli organisms with unchanged cultural, morphological, biochemical, and serological properties. The mutants proved apathogenic for albino mice at intravenous injection of a 6-hour broth culture at the rate of 0.3 cm3 or an endotoxin in the same dose. Neither were they enteropathogenic for pigs when inoculated into intestinal segments. They could be used as vaccinal strains.

Animals↗
PubMed1978

Ultrastructural characterization of stable L-form cells from Erysipelothrix rhusiopathiae and of accompanying artifacts.

The stable L-form of Erysipelothrix rhusiopathiae is a typical protoplast type L-form. Cells are surrounded by a trilamellar cytoplasmic membrane only. They grow in form of aggregations in liquid media and their diameters vary between 0.1 and 2 micrometer. Always a large portion of cells undergoes lysis. It seems to be characteristic for L-form cultures of E. rhusiopathiae that always many artifact structures are formed. The artifacts are spherical particles with diameters of 0.1 micrometer to more than 3 micrometer. They can be differentiated from L-form cells only by electron microscopy. The artifacts consist of electron dense amorphous material and their surface is irregular without a clear boundary line. Obviously, these artifacts are produced from protein components of the medium and from cytoplasmatic components of the lysing L-form cells.

Animals↗
PubMed1978

Histoautoradiographic studies on the fate of 3H-thymidine labelled L-forms of E. rhusiopathiae in albino mice.

L-forms of Erysipelotrix rhusiopathiae labelled with 3H-thymidine were intravenously administered to albino mice. Autoradiographic studies of the liver, kidney and spleen were undertaken at periods ranging from 2 minutes to 15 days. On the second minute following the administration of the radioactive material whole labelled microorganisms and chains of silver grains were recovered in the examined organs. Up to the 15th minute labels were observed also in the cells of the RES. Following the 30th minute the silver grains were positioned at a characteristic site in the Golgi region of the hepatocytes. At the same time in the kidney they were localized in the glomerular space and in the lumen of the renal tubules, whereas in the spleen - mainly around the megakaryocytes. By the 15th day labelling gradually diminished, single silver grains being found over some nuclei of megakaryocytes, liver and kidney parenchymal cells. The present study throws light over some aspects of the interrelationship between the micro- and macroorganism concerning the mechanisms of desintegration, elimination and the uptaking of labelled microbial DNA.

Animals↗