[Strategy of viral replication].

Virus replication is a multistep process which is realized mostly by virus-coded enzymes and in a small part by cell-coded enzymes. Affection of the virus-coded enzymes can be, and is, utilized to restrict virus replication without damaging the host cell. The article provides basic information on the most important steps of viral replication and processes which can be affected in the course of antiviral therapy.

[Cytotoxic changes in cell cultures induced by newly isolated strains of Campylobacter pylori].

Suspensions of primocultures of two strains of Camplyobacter pylori, isolated from bioptic materials collected from patients with nodular hyperplasia of the pyloric antrum and with gastric ulcers were inoculated to 20-hour confluent or almost confluent cell cultures line VERO, McCoy and MA 104 in test tubes and Petri dishes. Both strains of C. pylori adhered markedly to cell lines VERO and McCoy and after 72 hours led to marked morphological changes of the cells.

Local and systemic antibody response in infants after oral administration of inactivated enteropathogenic E. coli serotype O111 and O55.

In ten infants divided into two groups (up to one month of age and at 2-7 months of age) the dynamics and formation of different antibody isotypes produced locally in the intestine and in serum after orally administered inactivated enteropathogenic E. coli strains O111 and O55 was followed during 30 d after the first and booster dose by using an indirect immunofluorescence method. Infants up to one month of age produced antibodies of IgM isotype in stool together with the IgA isotype after the first and booster dose of the vaccine against both antigens.

Treatment of gastrointestinal infections in infants by oral administration of colostral antibodies.

Passive immunization used for treatment of gastrointestinal infections represents a safe and effective method in premature and full-term newborns, avoiding the use of oral antibiotics.

Biological activities of enterotoxin from Vibrio cholerae non-01.

The specific antiserum 54(2) prepared in rabbits by combined intraperitoneal and intravenous immunization with the enterotoxin from Vibrio cholerae non-01 was found to neutralize the enterotoxin biologic activity expressed by rabbit skin vascular permeability and hemorrhage factors. The inhibition of biologic activity was also observed when using antiserum to choleragen, but choleragen could not be neutralized by specific serum 54(2). The enterotoxin was also inactivated when heated at 100 degrees C for 10 min, but heating at 56 degrees C for 30 min had no influence on its biologic activity.

Toxic factors of Aeromonas hydrophila and Plesiomonas shigelloides.

In detail, exoproducts of Aeromonas hydrophila and Plesiomonas shigelloides were studied on the pathogenesis of diarrhoea. Enterotoxin, hemolysin and a cytotoxic factor were found in a fraction of culture filtrates of Aeromonas hydrophila with a molecular weight of approximatley 60,000. Apart there from a cytotoxic factor was also found in a fraction with molecular weight above 100,000.