Biomedical subjects

E Claassen

Publications and source records attributed to E Claassen.

131 records · Page 8Linked to original sources

PubMed1984

TNP-enzyme conjugates for the detection of anti-TNP antibody producing cells in vivo.

After injection of TNP-KLH in mice and TNP-BGG-PEN in rabbits, anti-TNP antibody-forming cells were observed in the spleen. When cryostat sections of the stimulated spleen were incubated with TNP-HRP conjugate, and then treated for HRP cytochemistry, the cytoplasm of anti-TNP-forming cells was stained red. When similar sections were incubated with TNP-AP conjugate, and then treated for AP cytochemistry, the cytoplasm of anti-TNP-forming cells was stained blue. After simultaneous incubation with TNP-AP conjugate and PEN-HSA-HRP conjugate, followed by treatment for HRP cytochemistry and AP cytochemistry, anti-TNP-forming cells with a blue cytoplasm and anti-PEN-forming cells with a red cytoplasm could be distinguished in the same spleen section.

Alkaline Phosphatase↗

PubMed1983

A comparative study on the effectiveness of various procedures for attachment of two proteins (L-asparaginase and horse radish peroxidase) to the surface of liposomes.

Five different ways of association of proteins with the surfaces of liposomes were compared. L-asparaginase (L-asp.) and horse radish peroxidase (HRP) were used as proteins since these show a large difference in their numbers of amino groups. Liposomal association was performed by way of: 1) non-specific coating of empty liposomes; 2) incorporation after 'hydrophobisation' with palmitoylchloride; 3) as 2 with dodecanoic acid; 4) coupling to phosphatidylinositol (PI) already incorporated in the liposomal membrane; and 5) as 4 with phosphatidylethanolamine (PE). The relative effectiveness of the different procedures for coupling of the proteins to liposomes as determined by the enzyme activities of intact liposomes shows a large variation, dependent on both the method used and the protein.

Asparaginase↗

PubMedDate not supplied

Oral administration of TNP-Lactobacillus conjugates in mice: a model for evaluation of mucosal and systemic immune responses and memory formation elicited by transformed lactobacilli.

Safe live vector systems are being developed for oral delivery of antigens. A transformation system for indigenous Lactobacillus species of the gastrointestinal tract is described. Model systems were set up to evaluate immune responses. Orally administered trinitrophenylized (TNP) Lactobacillus were examined for their ability to induce immunological memory formation via determination of specific antibody titres in serum. We demonstrate a direct correlation between the level of systemic memory formation, as revealed by specific anti-TNP IgG serum antibodies, and the TNP substitution ratio of the Lactobacillus suspension used for oral priming. The specific IgG anti-TNP serum titres were comparable to or even higher than the titres of parental intraperitoneally primed animals. These results demonstrate the feasibility of using orally administered antigen-Lactobacillus as a future approach to vaccination.

Administration, Oral↗

PubMedDate not supplied

Immunocytochemical techniques to investigate the pathogenesis of infectious micro-organisms and the concurrent immune response of the host.

For poultry as well as for mammalian species used for scientific research, many immunocytochemical techniques have been developed to investigate in detail the interaction between infectious micro-organisms and the nonspecific and specific immune systems of the host. In this review three techniques have been described with all technical details necessary to perform them correctly: (1) single immunocytochemical staining to detect the infectious micro-organisms in situ at their site of infection, (2) double immunocytochemical staining to visualize simultaneously the infectious micro-organism and the host cellular response to investigate their interactions, and (3) detection of plasma cells producing antibodies specific to the micro-organism. Of the three techniques the results are described when applied on chicken tissues infected with various micro-organisms, such as Marek's disease virus, chicken anemia virus, infectious bursal disease virus and Eimeria tenella.

Animals↗

PubMedDate not supplied

Use of spermicide and impact of prophylactic condom use among sex workers in Santa Fe de Bogota, Colombia.

BACKGROUND AND OBJECTIVES: Condom use is one of the most important preventive measures sex workers can take to reduce the risk of becoming infected with a sexually transmitted disease. However, a client may refuse to use a condom when requested. Some sexually transmitted disease prevention programs are recommending that sex workers use spermicide as an alternative prophylaxis when a condom is refused, yet little is known about the effect of this recommendation on prophylactic condom use. GOAL: To determine if using spermicide, either in conjunction with condoms or as a backup, influenced overall condom use among a group of sex workers at high risk of sexually transmitted diseases in Santa Fe de Bogota, Colombia. STUDY DESIGN: Participants were assigned randomly to one of three condom use groups: use of condoms only (Condoms Only), use of condoms and spermicides concurrently (Condom and Spermicide), or use of spermicide when condoms were refused (Spermicide as a Backup). A total of 199 sex workers entered the study and were asked to return for follow-up every 2 weeks for a period of 12 weeks. RESULTS: Women assigned to the Spermicide as a Backup group used a condom for an average of 78.1% of their reported acts of intercourse, compared with an average of 94.5% in the Condom Only and 92.3% in the Condom and Spermicide groups. However, women in the Spermicide as a Backup group used a condom or spermicide for an average of 96.9% of their acts of intercourse. Condoms were used for every intercourse act by less than 5% of the women in the Spermicide as a Backup groups, compared with 50.7% in the Condom Only group and 41.2% in the Condom and Spermicide group (P 0.001). When condoms were not used, client refusal was the primary reason reported. The incidence of sexually transmitted diseases and other urogenital inflammations in all groups was lower than expected. CONCLUSIONS: Among Colombian sex workers, condom use declined substantially when women were instructed to use spermicides if they were unable to persuade their partner to use a condom. However, these same women usually used the study spermicide as an alternate prophylaxis.

Adult↗