Protective immunity against Vibrio cholerae infection in the rabbit.

The DIC model (Duodenal Inoculation with ligation of the Cecum in rabbits) was employed to study experimentally induced cholera and the related protective immunity. Duodenal inoculation (DI) without ligation of the cecum with live V. cholerae organisms did not cause any disease symptom but induced protection against subsequent challenges with homologous and heterologous organisms for up to 24 months.

Virus, bacteriophages and water purification.

Water can be a vector of viral disease, but direct virological analysis of water has logistic and practical limitations. Viruses of major importance for water hygiene (e.g.

Migration and proliferation of primordial germ cells in the rat.

Information about early primordial germ cell (PGC) formation and migration in rats is lacking. In utero developed and in vitro cultivated whole rat embryos were studied on days 10-13 postcoitum (p.c.

Serotyping of Aeromonas species using passive haemagglutination.

Antisera were raised with heat-killed vaccines prepared from 25 Aeromonas hydrophila strains, 4 A. sobria strains and one A. caviae strain.

N-nitrosamines and nitrosatable compounds in rubber nipples, pacifiers and other rubber and plastic commodities.

In 1983 and 1985, rubber teats and pacifiers from the Dutch market were analysed for N-nitrosamines (NA) and nitrosatable compounds (NC) by extraction with an artificial saliva test solution (24 h, 40 degrees C). NC were determined as NA (gas chromatography-thermal energy analysis) after nitrosation. In 1983, the total content of NA and NC varied from 4-40 micrograms/kg and 50-3700 micrograms/kg, respectively (18 samples).

Cloning and nucleotide sequence of rat ornithine decarboxylase cDNA.

The enzyme ornithine decarboxylase (ODC; EC 4.1.1.

Inflammatory bowel disease: one condition or two?

Demographic data obtained from epidemiological studies of Crohn's disease and ulcerative proctocolitis in Regio Leiden (Leiden health care region) were compared. Ulcerative colitis (6.8 cases/10(5) population/year) had an incidence almost twice that of Crohn's disease (3.

Inhibition of measles virus-induced cell-cell fusion with a monoclonal antibody directed against the haemagglutinin.

A neutralizing monoclonal antibody (C26-15) against the haemagglutinin (H protein) of measles virus was generated which caused cell-cell fusion inhibition in cultures of measles virus-infected cells. It was shown that this phenomenon coincided with a down-regulation of the expression of both the H protein and the fusion (F) protein. We also showed cell-cell fusion inhibition with a polyclonal rabbit serum directed against Tween-ether inactivated measles virus, which did not contain biologically active antibodies against the F protein.

The toxicology of bromide ion.

Inorganic bromide is widely distributed in nature. Its natural physiological role in animal life is unknown. More than a century ago bromide was introduced in medicine as an antiepileptic drug.

Human anti-idiotypic T lymphocyte clones are activated by autologous anti-rabies virus antibodies presented in association with HLA-DQ molecules.

The regulatory function of antigen-specific T cells in human antibody responses to protein and carbohydrate determinants of many viral and bacterial antigens has extensively been studied in systems involving in vitro triggering of B cells by antigens or polyclonal activators. Although amply documented in experimental murine models, the existence of T helper cells with receptor specificity for idiotypic determinants of B cell immunoglobulins has not been demonstrated in a human system. We are interested in T helper cell recognition of idiotypic determinants of virus-specific antibody, secreted by human B cells in response to viral antigens, and in the role which such idiotype-specific T helper cells play, alone or in concert with virus-specific T helper cells, to regulate the antibody response.

Incidence of Foodborne Disease in the Netherlands: Annual Summary - 1981.

Data on the incidence of foodborne disease in 1981 are presented. A total of 415 incidents affecting 3618 ill persons was analyzed. In 122 incidents (1683 cases) the etiology was established: micro-organisms appeared to be the main causative agents.

Detection of Mold in Food by Enzyme-Linked Immunosorbent Assay.

Evaluation of the enzyme-linked immunosorbent assay (ELISA) for detecting a mold-specific, heat-stable and water-soluble antigen demonstrated the potential of the method for detecting molds in food products. The mold antigen, as produced by Penicillium spp. and Aspergillus spp.

Use of Preservatives to Delay Toxin Formation by Clostridium botulinum (Type B, Strain Okra) in Vacuum-Packed, Cooked Potatoes.

Storage at temperatures below 4°C prevents growth and toxin production by Clostridium botulinum in vacuum-packed, cooked potatoes. The use of preservatives as an additional, built-in safety factor has been investigated. Dipping potatoes in a solution of ascorbic and citric acid before vacuum-packing and cooking (95°C for 50 min) inhibited growth and toxin production by proteolytic C.

Incidence of Foodborne Disease in the Netherlands: Annual Summary - 1980.

Data on the incidence of foodborne disease in 1980 are presented. A total of 272 incidents affecting 1298 ill persons were analysed. In 64 incidents (337 cases), the etiology was established; micro-organisms appeared to be the main causative agents.