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Biomedical subjects

J S Teppema

Publications and source records attributed to J S Teppema.

26 records · Page 2Linked to original sources

Immunotherapy by intralesional injection of BCG cell walls or live BCG in bovine ocular squamous cell carcinoma: a preliminary report.

Cows of the Dutch Frisian and Maas-Rijn-IJssel breed with histologically confirmed ocular squamous cell carcinoma showed complete regression of the primary tumor in 70 or 60% of the cases after intralesional injection of a BCG cell wall or live BCG vaccine, respectively. Recurrence of the tumor was observed in 57% of the animals treated with BCG cell walls and in 25% of the animals treated with live BCG vaccine. Spontaneous regression was seen in 20% of the untreated cows. In a second control group, radical surgery, the most successful treatment for primary stage I tumors in humans, resulted in a 90% cure. Influence of immunotherapy on metastases could not yet be fully evaluated. White blood cell counts were not changed after therapy. It was not possible to link a favorable response to BCG therapy with the intensity of the delayed type hypersensitivity (DTH) reaction to purified protein derivative of mycobacteriae (PPD) or the formation of antibodies to BCG as determined by a micro-enzyme-linked immunosorbent assay. However, in animals that showed tumor regression, the DTH reaction to PPD had a tendency to persist for a longer period of time. It was concluded that 1) block resection was the best method of treatment for this tumor, 2) a single intralesional injection of a BCG cell wall vaccine was as effective as live BCG vaccine in the induction of complete regression of the primary tumor, 3) in this preliminary study BCG cell wall vaccine was less effective than live BCG vaccine in the prevention of recurrence, and 4) this naturally occurring tumor model is well suited for the study of the influence of BCG immunotherapy in a primary stage I tumor.

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Mousepox in the Netherlands.

Two independent outbreaks of ectromelia in mice occurred in The Netherlands. In both cases, the causative virus was isolated and identified as ectromelia virus on the basis of serology, demonstration of antigen by indirect immunofluorescence, negative contrast electron microscopy, morphology of lesions on chorioallantoic membranes of embryonated chicken eggs, and cytopathogenicity for mouse cells. Inoculation of the virus into the dermis of rabbits demonstrated a low virulence for this species.

Animals↗

Cloning and expression of a deoxyribonucleic acid fragment that encodes for the adhesive antigen K99.

Deoxyribonucleic acid fragments of the naturally occurring conjugative K99 plasmid were cloned into vectors pBR322 and pBR325. The smallest deoxyribonucleic acid segment obtained that still expressed K99 was 4.5 megadaltons in size. With regard to the serological, adhesive, and morphological properties, no differences in the nature of the K99 antigen was observed between Escherichia coli strains carrying recombinant plasmids and those carrying pRI9901. Furthermore, the regulation of K99 expression from the recombinant plasmid deoxyribonucleic acid was similar to that from pRI9901. the low level of K99 expression in E. coli K-12 compared with natural K99-producing isolates seems to be host specific.

Animals↗

Ultrastructural aspects of experimental swinepox with special reference to inclusion bodies.

A light and electron microscopic study was performed on pox-like epidermal lesions in an experimentally infected pig. Light microscopical investigation of semithin sections revealed the presence of nuclear vacuoles and of different types of cytoplasmic inclusions. In electron microscopical studies large numbers of both immature and mature virus particles and the cytological changes indicative of pox virus infection were observed. Various types of intra-cytoplasmic inclusions -- i.e. fibrillar inclusions, crystalloid-containing dense inclusions, complex membraneous inclusions and dense homogeneous inclusions -- were encountered in addition to viroplasms and nuclear vacuoles. Because of the presence of vacuoles in nuclei of stratum spinosum cells the diagnosis swine pox by swinepox virus was most probable. These nuclear vacuoles have not been described in swine pox caused by vaccinia virus, the only other known cause of pox in swine.

Animals↗

Cellular changes in primary rabbit kidney cells resembling those caused by certain viruses.

Changes suggestive of being caused by a virus have recently been observed in primary rabbit kidney cells. In their nature and development they resembled those of parvoviruses. The changes were found in cultures from rabbits from various sources within and outside The Netherlands. If the changes are caused by a viral agent, this agent is most probably of rabbit origin, as exogenous infection, for example through trypsin, could almost certainly be excluded. However, no virus has yet been isolated nor could particles be made visible by electron microscopy in affected cells. Hemagglutination could not be demonstrated nor could antibody in rabbits. The possible nature of these changes will be discussed.

Animals↗