E Teruel-López | PubMed Health

PubMed1992

[Cytopathogenic effect of diphtheria exotoxin in cultured chick embryo fibroblasts].

One hundred fifty strains of Corynebacterium diphtheriae were studied from patients with symptoms of diphtheria and from healthy persons. 136 strains (90.67%) belonged to the mitis biotype, 12 (8.0%) and 2 (1.33%) to gravis and intermedius biotypes respectively. Toxigenicity was determined by traditional in vivo methods with rabbits and plaque immunodiffusion in KL-virulence medium. From the 136 mitis biotype strains studied, 130 (95.58%) showed positive toxigenicity by both methods and 11 strains (91.66%) from gravis biotype and 2 (100%) of intermedius biotype gave same results. The cellular cytotoxicity of the diphtheriae toxin was tested on culture of chicken embryo fibroblast and were positive in 132 (97.05%) strains of mitis biotype, and in all strains of gravis and intermedius biotypes. These results suggest that the cytotoxicity test seems to be a more sensitive method for detecting diphtheriae toxin production.

Animals↗

PubMed1991

[Dengue. A review].

Dengue fever is an acute and infectious disease produced by a togavirus. This clinical syndrome being benign or severe like the Dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS), has been associated with a very high mortality rate specifically in children with different ages and those under 1 year of age from mothers having antibodies to dengue virus. Other groups with potential risk factors are those patients with chronic diseases like asthma, sickle cell anaemia and diabetes mellitus. Dengue virus show a highly tropism for endothelial reticulum system as the bone marrow, spleen, liver and lymph nodes where viral antigens can be demonstrated by several immunological methods. The pathogenesis of the DHF/DSS can be considered to result from a delayed type hypersensitivity reaction where antigen-activated T lymphocytes release a variety of biologically active chemical mediators (lymphokines) with further effects on blood clotting system and vascular permeability producing the symptoms of shock and hemorrhage seen in these cases. The rapid control and hospitalization of the patients allow them to get a fast recovery without any sequelae.

Adolescent↗