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Biomedical subjects

F Rátz

Publications and source records attributed to F Rátz.

At least 19 recordsLinked to original sources
PubMed2001

Review of the microbiological, pathological, and clinical aspects of bovine mastitis caused by the alga Prototheca zopfii.

The mastitis caused by P. zopfii alga is a disease of high-producing, machine-milked dairy cows. It occurs worldwide in tropical and temperate climatic areas, and mostly appears sporadically in a therapy-resistant form. However, in poorly managed dairy herds it may be endemic, causing serious economic losses as a result of decreased milk quality and quantity and culling of infected animals. The biological properties of this pathogenic alga, the laboratory methods available for its isolation and identification, the pathological and clinical features of this form of mastitis, and the principles of its control are reviewed in this paper.

Animals↗
PubMed2001

Prototheca zopfii mastitis in dairy herds under continental climatic conditions.

In the last 2 years 223 cases of bovine mastitis caused by Prototheca zopfii infection were identified in 32 large-scale dairy herds. All of these farms were in Hungary, which has a continental type, temperate zone climate. Both the sporadic and epidemic forms of P. zopfii mastitis were observed. All the herds affected by the epidemic form had poor hygienic conditions and suffered from several managerial faults, but no specific predisposing factors could be identified. In almost all of the cases, the type II variant of this pathogen was isolated; however, the type III variant was isolated from three cows. The cows had a higher chance of new infection in the early weeks of lactation and in the summer. The P. zopfii infection usually resulted in a chronic subclinical, or mild clinical, inflammatory process in the udder, and was followed by a dramatic loss in milk production and a permanent increase in somatic cell count. The histopathological findings could be characterized as a progressive interstitial mastitis associated with alveolar atrophy. The self-recovery rate was very low.

Animals↗
PubMed1991

Pathological and immunological study of goose embryos and goslings inoculated with an attenuated strain of Derzsy's disease virus.

An attenuated Derzsy's disease virus strain, designated BAV, was studied in goose embryos. A total of 248 embryonated goose eggs, coming from a susceptible laying flock with no yolk-derived immunity (group I) and from a vaccinated laying flock (group II) were used. The eggs were inoculated into the allantoic cavity with 10(1.9), 10(2.9) or 10(3.9) EID 50/0.2 ml virus on day 12 or day 20 of incubation. Embryos were killed at 5-day intervals. The dead embryos and the hatched goslings (up to 2 weeks of age) were examined by gross and histopathological methods. Reisolation of the virus from the organs was attempted, serum samples were tested for the presence of antibodies, and lymphocytes separated from the circulating blood were used in the lymphocyte stimulation and immunorosette formation tests. Embryos of both groups I and II, inoculated at either time of incubation, showed a body mass gain inferior to that of the controls. Sixteen (group I) and 12 (group II) of the embryos inoculated on day 12 of incubation died. Some (group I: 15, group II: 6) of the embryos inoculated on day 20 of incubation failed to hatch. The pathomorphological changes seen in the embryos killed between days 17 and 22 of incubation were of degenerative character. In embryos killed later (between days 23 and 58 of incubation) the degenerative changes were accompanied by infiltration by inflammatory cells. Reisolation of the virus strain was mostly successful between postinoculation (PI) days 5 and 10. Specific virus-neutralizing antibodies and cellular immune response were demonstrable already at hatching.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Pathological and immunological study of goose embryos experimentally infected with duck plague virus.

A total of 240 embryonated goose eggs obtained from two susceptible flocks were used. Half of the eggs were inoculated into the allantoic cavity with a virulent strain (7593) of duck plague virus isolated from an acute outbreak, and the other half were inoculated with the attenuated vaccine virus (KAPEVAC). Ten, 100 or 1000 CPU/0.1 ml virus were given on days 12 and 20 of incubation. Embryos that died and surviving embryos killed at 5-day intervals were examined by light and electron microscopy. The yolk and the serum of embryos that survived until hatching were assayed for antibody content. Lymphocytes separated from the blood were used for the immuno-rosette formation and lymphocyte stimulation tests. Pathomorphological changes indicative of virus replication occurred in the liver, kidney, myocardium, gizzard muscle and chorioallantoic membrane (CAM) of the embryos in the case of both virus strains. The time of onset and severity of these changes and the time and rate of embryonic mortality depended on the virulence of the strain used for inoculation, the virus dose and the time of inoculation. Virus-neutralizing (VN) antibodies were demonstrable neither in the yolk nor in the serum of goslings exsanguinated after hatching. The lymphocytes recognized the virus antigen in the in vitro cellular tests and responded to it with blastogenic transformation. As opposed to adult birds, in the embryos duck plague virus infection did not cause damage to the digestive tract mucosa and the lymphoid organs.

Animals↗
PubMed1990

Characterization of Actinobacillus strains isolated from aborted swine fetuses.

Eleven Actinobacillus strains were isolated in pure culture from 12- to 13-week-old aborted swine fetuses. Apart from minor biochemical differences, they resembled strains isolated from sow vaginas by Ross et al. (1972) in the U. S. A. Some of the strains agglutinated sheep, cattle and horse but not pig, dog and chicken erythrocytes. Haemagglutination was mannose resistant and could be inhibited by specific hyperimmune serum. Heating above 70 degrees C diminished or abolished haemagglutination of the cultures. Electron microscopy showed no fimbriae on the surface of the bacteria.

Abortion, Veterinary↗
PubMed1982

Pilus antigen 987P produced by strains of Escherichia coli serotypes O141:K--, H- and O8:K85:H--.

Escherichia coli strains isolated from the alimentary tract of 68 weaned and 44 unweaned pigs with diarrhoea in various parts of Hungary, were tested for the presence of pilus antigens K88, K99 and 987P. K88 was detected in 30% of the strains from newborn pigs and in 12% of the strains isolated from weaned pigs. One strain carried K99. Based on agglutination test and immunoelectron microscopic studies with specific absorbed antisera, five non-haemolytic E. coli strains isolated from newborn pigs were found to produce so-called 987P pili. Three of these strains were designated serologically as O8:K85:H--,987P+ and two as O141: K--:H--,987P+. The Y1 cell assay, the infant mouse assay, and the ligated intestinal loop assay in less than 3-week-old pigs indicated that none of the strains produced heat-labile enterotoxin but all produced a heat-stable enterotoxin detectable in infant mice and in pig loops (STa). All the strains induced diarrhoea in newborn, colostrum deprived pigs and colonized the lower small intestine by adhesion to the villous epithelium. The results have confirmed earlier findings about adhesive virulence attributes caused by 987P pili.

Animals↗
PubMed1979

Absorption of colostral immunoglobulins in suckling piglets.

The three portions of the small intestine of 18 neonatal piglets were examined by using the so-called scroll technique evolved by the authors and in cross sections. The chemical constitution and the immunoglobulin content of undigested protein droplets being under absorption were studied. An intensive absorption of immunoglobulins was demonstrated in the body of each cuticulated cylindric epithelial cell of the mucosa covering the jejunum and the proximal two-third of the ileum. Absorption was the most intensive, though variable by area, in the jejunum. It was demonstrable 4 hr after birth and reached the highest intensity between 8 and 12 hr, then tended to decline. In the protein droplets alpha-amino acids, neutral mucopolysaccharides and protein-bound Ca2+ were detected. Alkaline phosphatase activity was demonstrated around the droplets. Immunofluorescence and immunoperoxidase reactions proved the presence of immunoglobulins, first of all of IgG, in droplets. Electron microscopically, the microvilli of the involved epithelial cells were swollen, sometimes neighbouring ones were pushed away from each other; in the same areas, an electron-dense substances (colostrum) covering the enterocytes was streaming through the tubulovascular network of cells to the perinuclear region, where it appeared in spherical droplets.

Animals↗