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Biomedical subjects

A Valkoun

Publications and source records attributed to A Valkoun.

At least 19 recordsLinked to original sources
PubMed1998

[Myiasis in a skin tumor].

A case of myiasis of a cutaneous tumour, a melanoblastoma in the right axilla of an 87-year old woman is described. After two years of illness in the last months of life an attack of the tumour by larvae of the fly Lucilia sericata (Meigen, 1826) was observed. This fly is the most frequent causal agent of tissue, cavity, ocular and urogenital human myiasis in Central Europe. Usually, injured or seriously ill patients are attacked by the larvae in urban as well as rural conditions. This is the first described case of myiasis located in a tumour.

Aged↗
PubMed1995

[Diagnosis of acquired toxoplasmosis using simultaneous determination of specific immunoglobulins M, A and E].

Simultaneous estimation of specific immunoglobulins M,A,E was tested in sera of 57 patients with confirmed acquired toxoplasmosis (24 acute and 33 subacute or chronic) using immunosorbent agglutination assay (ISAGA) and immunofluorescent tests (toxoplasma antibody-total and IgM). The antigen for ISAGA was prepared from tissue cultures HeLa infected with Toxoplasma gondii virulent strain P. Toxoplasmas were maintained in tissue cultures continuously for 18 years. High levels of IgM antibodies were found in all 24 patients during the acute phase of toxoplasmosis (0-5 month after onset). IgA antibodies were found also in all but one and IgE in 71% of these patients. IgM antibodies persisted for the longest period and it was possible to find them in 14% of patients 3 years or longer after the onset, IgA antibodies persisted for 9 months similarly as IgE (with one exception after 2 years). Simultaneous estimation of specific immunoglobulins M,A,E combined with immunofluorescent tests makes the diagnosis of Toxoplasma infection more reliable.

Adolescent↗
PubMed1992

Microbial causative agents of male urethritis.

The incidence of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, Neisseria gonorrhoeae and Trichomonas vaginalis was studied in men with urethritis. Out of 150 examined men 48.7% had the positive isolation of U. urealyticum, 26.0% C. trachomatis, 22.7% N. gonorrhoeae, 18.7% M. hominis and in one (0.7%) patient T. vaginalis was found. None of the above mentioned microorganisms was detected in 24.7% of examined men. In 43.3% cases only one agent was isolated. In 23.3% of the men the combination of two agents, in 8.0% the combination of three and in 0.7% even the combination of four studied microorganisms was observed. C. trachomatis was most frequently observed in combination with N. gonorrhoeae (15 cases) and U. urealyticum (14 cases). M. hominis and U. urealyticum occurred simultaneously in 22 examined men.N.gonorrhoeae was most frequently found together with U. urealyticum (16 cases). Concerning the occurrence of other bacteria and yeasts, no significant difference was found between the groups positive and negative for the above mentioned microorganisms.

Adult↗
PubMed1991

[Factors affecting the results of culture of Chlamydia trachomatis in a McCoy cell culture].

The authors confirmed that the sensitivity of cultivation of the laboratory strain Chlamydia trachomatis, serotype E in a McCoy cell culture is increased by centrifuging of the inoculum and addition of cycloximidine to the cultivation medium. Conversely, postcentrifugation sedimentation of the inoculum and addition of glucose to the medium has no effect. To meet the needs of the parasite and the host cells the glucose content in the basic p component of the medium--MEM is sufficient. Exchange of the basic constituent of the medium--MEM for RPMI 1640 did not prove useful in the cultivation of the laboratory strain of chlamydia. In cell cultures where medium with RPMI 1640 was used chlamydia inclusions were not found.

Bacteriological Techniques↗
PubMed1990

Laboratory diagnosis of acute toxoplasmosis by immunosorbent agglutination assay (IgM ISA).

A group of 401 patients suspected for toxoplasmosis was examined by the indirect immunofluorescent antibody test (IFAT). All patients positive in IFAT (176) were examined by the immunosorbent agglutination assay (IgM ISA). In the IgM ISA 154 of them were negative, 10 temporarily and 12 high-positive. Some of high-positive patients were examined repeatedly; decrease of high levels of specific IgM antibodies occurred 2-9 months after the first examination. For the IgM ISA antigen prepared from peritoneal exudate of experimentally infected mice was used. The antigen was stable at 4 degrees C or in liquid nitrogen at least 1 year. The IgM ISA combined with IFAT and IgM IFAT was proved satisfactory for the diagnosis of acquired acute toxoplasmosis and can be recommended for laboratories with lower capacity.

Acute Disease↗
PubMed1989

[Visualization of the developmental cycle of Chlamydia trachomatis using electron transmission microscopy].

Using a transmission electron microscope, the authors investigated the developmental cycle of Chlamydia trachomatis, serotype L2 in McCoy cells. The cell monolayer was examined closely after inoculation with the laboratory strain and subsequently after intervals of 5, 10, 15, 20 and 30 hours. Soon after inoculation the authors observed attachment of elementary bodies to the cell surface and their penetration into the cytoplasm. The transformation of the elementary body into a reticular one occurred via an intermediate body and was completed within 10 hours after inoculation. By division of reticular bodies an intracytoplasmic inclusion developed which attained 20 hours after inoculation the size of a cell nucleus. After a 30-hours interval the inclusion filled practically the whole cell and contained in addition to the elementary body also reticular and intermediate bodies.

Cells, Cultured↗
PubMed1985

Preservation of laboratory strains of Toxoplasma gondii in vitro.

A procedure to obtain viable stabilates of virulent laboratory strains of Toxoplasma gondii with a prolonged storage life is described. Viable endozoites recovered from the sediment of mouse exudate or tissue cultures (LEP, HeLa) are suspended in Eagle's MEM medium supplemented with 10% calf serum and 10% dimethylsulfoxide and sealed into glass ampoules of 1-2 ml in volume. The ampoules are placed in an apparatus for gradual cell freezing, frozen to --35 degrees C at a rate of --1 degree C/min, and stored in liquid nitrogen. Reinoculation experiments on mice given the suspension intraperitoneally confirmed that such Toxoplasma gondii strains retain viability for at least 4 years. This in vitro preservation technique is compared with the analogous T. gondii preservation procedures described in the literature.

Animals↗
PubMed1983

Continual cultivation of Toxoplasma gondii on HeLa cells.

Continual cultivation of Toxoplasma gondii in monolayers of HeLa cells has been performed for 6 years. The toxoplasmas were then used for serial cultivation experiments. While searching for optimal conditions for toxoplasma inoculation it was found that infected HeLa cells which were scraped off the glass were a more suitable inoculum than those released by trypsinization. The optimal dose was one zoite per 12 host cells, medium level height at adsorption 2 mm and adsorption time 90 min at 37 degrees C. The concentration of sodium bicarbonate ranging from 8.7 to 26.1 mM had no effect on the multiplication of toxoplasmas. In serial passages in Roux bottles, when the medium was changed every 2-3 days, the average yield of toxoplasmas was 6.2 X 10(6) per ml of medium (after the second change of medium, i.e., 7 days after inoculation). The toxoplasmas obtained in serial passages were suitable for purification studies, for preparation of small amounts of antigens and as an inoculum for suspension cultures.

Animals↗
PubMed1981

Preparation of purified toxoplasma gondii suspensions.

Simple methods for the preparation of purified suspensions of T. gondii zoites from mouse peritoneal exudate and HeLa tissue cultures are described. The suspensions from the mouse peritoneal exudate were prepared by mechanical disintegration of host cells and tryptic digestion. The average yield of purified Toxoplasma was 78%, with average purity of 99.96%. The suspensions from the tissue cultures were prepared by differential centrifugation and tryptic digestion. The average yield of Toxoplasma was 67% with average purity of 99.67%. An advantage of these procedures is their feasibility.

Animals↗