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Biomedical subjects

J Trávnícek

Publications and source records attributed to J Trávnícek.

At least 19 recordsLinked to original sources
PubMed1998

[Occurrence of struma in cattle in the Czech Republic].

In the years 1988 to 1995 among 1355 cattle examined in the frame of iodine deficiency studies in the Czech Republic 404 animals (30%) showed congenital struma. Clinical and postmortal findings are described. A monitoring of iodine content in milk showed lower values in herds with struma prevalence. The insufficient supply of iodine in these animals results from low iodine content of feed or from the goitrogenic influence of nitrate in drinking water or high content of crucifera in feed or other stress factors. An increased iodination of mineral mix in feed is highly recommended.

Animals↗
PubMed1993

The secondary antibody response induced in tissue cultures.

The conditions for induction of memory cells (B-MC) and evocation of the secondary antibody (Ab) response in tissue cultures (TC) were estimated. (1) In vivo primed B-MC cells were isolated 6-150 d after priming and stimulated in TC with different doses of sheep red blood cell (SRBC) antigen. The Ab response has a strict time and dose dependence: only small doses (10(5)) evoke a secondary response, high doses (10(8), 10(9)) a state of immediate tolerance. (2) Antigen added to TC directly with B-MC rescued their Ab production for a long period. Addition of the antigen 1 or 2 d after setting the TC, follows the Ab-response decay, comparable with virgin cells (B-ICC). (3) Primed B-MC stimulated in TC responded preferentially with an IgM secondary response; the same cell suspension adoptively transferred into isologous recipients switched into IgG cells. (4) Virgin, immunocompetent, B-ICC were primarily stimulated in TC with a small dose of antigen (10(5) SRBC); after 7 d of cultivation the cells were transferred into isologous recipients, SCID mice and into TC. In all cases, the secondary response of IgM was determined, 10 times higher than in the primary controls.

Animals↗
PubMed1993

The severe combined immunodeficient mouse as a model for Encephalitozoon cuniculi microsporidiosis.

Microsporidia have been recently recognized as opportunistic pathogens in AIDS patients. In attempt to develop an animal model with features similar to the infections observed in the immunodeficient patients, the adult severe combined immunodeficient mice (SCID) were administered both intraperitoneally and perorally by 2 x 10(7) spores of the murine isolate of E. cuniculi. The experimental inoculation caused a severe, fatal disease characterized by the dissemination of microsporidia into the host tissues. The dominant route of E. cuniculi dissemination in the SCID mice was continual direct extension from the site of inoculation to adjacent tissues and organs, terminating in hematogenous spread of infection in the host. The different courses of microsporidiosis in SCID mice relative to the mode of inoculation (i.p. vs. p.o.) was observed. The survival time of i.p. infected SCID mice was 3 weeks--vs. 5 weeks in p.o. infected SCID mice. Experimental microsporidiosis in SCID mice should provide a useful model for studies in microsporidial pathogenesis, mechanisms of resistance, immunotherapy, and in evaluating potential antimicrosporidial agents.

Animals↗
PubMed1993

Prophylactic and therapeutic immune reconstitution of SCID mice infected with Encephalitozoon cuniculi.

Severe combined immunodeficient (SCID) mice develop lethal infections, resembling opportunistic microsporidiosis of immunocompromised patients, after intraperitoneal (i.p.) inoculations of spores of Encephalitozoon cuniculi. In the present study, SCID mice reconstituted i.p. with 5 x 10(7) spleen cells from naive adult BALB/c mice 14 days prior to the i.p. injection of 10(7) spores were completely resistant to the infection, whereas control infected SCID mice developed clinical disease and died within 17 days post infection (DPI). In another experiment, SCID mice infected i.p. with 10(7) spores of E. cuniculi and after that (on DPI 7) injected i.p. with 5 x 10(7) spleen lymphocytes isolated from immune adult BALB/c mice were partially protected against the parasite (40% of the reconstituted mice survived). In both experiments, high levels of parasite-specific serum antibodies (mostly of the IgG-isotype) were detected in the infected immunocompetent BALB/c mice, whereas virtually no antibodies were found in the infected SCID mice. However, SCID mice reconstituted with either naive spleen cells or immune lymphocytes revealed humoral immune responses comparable with those of immunocompetent mice.

Animals↗
PubMed1989

Stimulating effect of Streptococcus faecalis on phagocytosis in gnotobiotic piglets.

The concentration of active phagocytes in peripheral blood remained in germfree pigs up to the age of one year approximately at the same level as found at the age of 7 d and did not exceed 0.3 X 10(9)/L of blood, whereas a steady increase was established in conventional pigs. Monoassociation of gnotobiotic piglets with Streptococcus faecalis increased during 24 h the concentration of circulating granulocytes and the concentration of active phagocytes. An even more pronounced effect was obtained when formolized S. faecalis cells were applied intraperitoneally to germfree piglets. This treatment elevated the phagocytosis index also in conventional piglets, as well as in germfree piglets previously given cyclophosphamide. Escherichia coli O 83 or a mixture of anaerobic bacteria did not cause any serious changes in the activity of phagocytosis in gnotobiotic piglets. S. faecalis seems to be a natural factor stimulating both the release of granulocytes from their depots as well as their phagocytic activity.

Animals↗
PubMed1989

Immunological state of adult germfree miniature Minnesota pigs.

Fundamental hematological and immunological data were obtained on sexually mature germfree miniature pigs fed, after the milk diet period, with cereal-type diet sterilized by gamma-radiation, and were compared with data of control conventional animals. Germfree adult pigs had a lower count of peripheral blood leukocytes with a lower percentage of neutrophil granulocytes and without any younger forms, a lower total serum protein level with a negligible amount of gamma and alpha 2 globulin fractions and a higher serum albumin and beta globulin level. In the mesenteric lymph nodes and in spleen, surface IgA-bearing cells predominated over surface IgG-bearing cells. Also a large amount of IgA-containing cells was found in the intestinal lamina propria, where the IgG cells were present in a negligible amount. IgM cells were the most frequent surface isotype in peripheral blood. The count of blood T lymphocytes was more than doubled.

Animals↗
PubMed1987

The minipig as a model in gnotobiology.

Due to its close physiological and morphological resemblance to man, the pig occupies an important position in biomedical research. The minipig lends itself particularly well to germfree research. It is easy to deliver, maintain, and utilize in isolators. The colostrum-free, newborn germfree piglet lacking passively obtained antibodies is of an exclusive use if distinguishing the factors of natural and adaptive immunity is needed. It fits also well in studies investigating the earliest mechanisms of antibody synthesis. Under germfree conditions, the pig has been proved an excellent model for testing the action of ionizing radiation as well as of selected bacterial strains when monoassociated. Recently, conventional pigs have been used also for studies in total or selective decontamination of the intestinal tract by antibiotics and strict isolation.

Animals↗
PubMed1987

Germ-free newborn baby.

Long term experience with germ-free animal experiments and technology encouraged us to apply the know-how in the field of the care of human neonates with presumed immunodeficiency. The program was carried out at the Faculty of Pediatrics of Charles University in Prague. The sterile caesarean section was performed within the plastic surgical isolator overlying the pregnant mother. A new type of this isolator adapted for the use in human medicine was designed and constructed. For the care of the neonate another special isolator was used. The whole isolator system included two rigid supply isolators, too. The newborn was sterile up to the age of 1 month. During this time, the newborns immunological capacity was investigated and found to be almost normal. Afterwards, the infant was gradually colonized with selected strains of bacteria and thus prepared for conventionalization.

Cesarean Section↗
PubMed1985

Selective decontamination, induced colonization resistance and connected immunological changes in piglets.

14-d-old conventional piglets were picked from normal piggery, washed with disinfectants, placed into isolators suitable for germfree work, fed a sterile diet and treated with peroral antibiotics (nalidixic acid, kanamycin, and nystatin). Beginning with day 5 or 7, Enterobacteriaceae were not found in feces. The absence of these bacteria was proved by inoculation of germfree newborn piglets with caecal content. In selectively decontaminated piglets, the white blood cell count in blood had fallen to 6 X 10(9)/L; this decrease was due to an extremely low number of granulocytes (to 0.8 X 10(9)/L). On day 35, IgG-positive cells almost disappeared from the spleen, whereas IgA cells were found in an unusually great amount. Corresponding changes in serum levels were established. The colonization resistance effect in Enterobacteriaceae-deprived piglets was confirmed; settling of introduced various E. coli strains did not occur or was delayed.

Animals↗
PubMed1983

The appearance of an IgD-like molecule on pig lymphocytes during ontogeny.

An IgD-like molecule was found on the surface of pig fetal lymphocytes using guinea pig anti-human IgD antisera and indirect immunofluorescence. The binding of antiIgD antisera could be specifically inhibited with human IgD. Surface IgD-like molecules were found later in ontogeny than surface IgM (after about 70 d of gestation in the spleen). There is evidence for their endogenous origin. The number of lymphocytes bearing IgD-like molecules rapidly increased during ontogeny.

Animals↗
PubMed1979

Gnotobiotic techniques.

A brief review is given of the development of equipment used for rearing germfree animals in various laboratories and of our experience with designing germfree isolators and with the technology of rearing germfree piglets is presented. The philosophy of isolation as applied to the animal as a biological unit, the elimination of contamination and the theoretical prerequisites of isolation were considered by Reyniers (1943, 1959) and Trexler (1960).

Animal Feed↗
PubMed1977

Equipment for germ-free caesarean section and baby care.

A germ-free isolator system was designed and constructed. It permits a sterile caesarean section and rearing of an infant under germ-free conditions. The system includes a plastic surgical and rearing isolator and two supply isolators; one of the supply isolators served as a transport mobile unit of staff participating in the sterile caesarean section and in the postnatal care of the germ-free newborn underwent to a special training and all of them were able to meet the high requirements of this work. The surgery itself was without complications. The newborn was absolutely sterile up to the age of 1 month; afterwards the infant was gradually colonized with selected strains of bacteria and thus prepared for conventialization. In the course of this work further possibilities of application of gnotobiological techniques in pediatrics were proposed (e.g. care of premature, high-risk neonates).

Animals↗
PubMed1975

The role of immune pig colostrum, serum and immunoglobulins IgG, IgM, and IgA, in local intestinal immunity against enterotoxic strain in Escherichia coli O55 in germfree piglets.

The protective effect of pig immune colostrum, serum and immunoglobulins IgG, IgM and IgA against the enterotoxic strain of Escherichia coli O55, was studied in newborn germfree piglets. This strain produced accumulation of fluid and dilatation of intestine when injected into the ligated ileal segment of germfree piglets, which is considered to be the typical effect of enterotoxins. Erosion of the intestinal epithelium and penetration of bacteria into the submucosa were also observed. Immune serum, colostrum and all the immunoglobulin classes used produced a local protective effect, IgA being most effective. The mechanism of protection conferred by these immunoglobulins is discussed with respect to the possible pathogenic action of enterotoxic Escherichia coli O55 in the intestinal tract of immunologically virgin germfree piglets.

Animals↗