Tobramycin is an aminoglycoside that is used therapeutically for chronic pulmonary infection that occurs in cystic fibrosis patients. The effect of this antibiotic on Fc-receptor expression was investigated using rat alveolar macrophages. When macrophage monolayers were incubated for 30 min with low concentrations of tobramycin (0.03-2.4 micrograms/ml) similar to those found in the cystic fibrosis lung, Fc-receptor expression was enhanced. This effect was dose-, temperature- and time-dependent. After 1 h pre-incubation antibody-labelled erythrocyte (EAG) binding returned to normal values and after 2 h inhibition was observed. When culture supernatants prepared from antibiotic-treated macrophages were incubated with EAG for 30 min, binding of these cells to the macrophages was decreased. This inhibition was directly proportional to the amount of supernatant added to the red cells and was greatest when the supernatant had been prepared from macrophages incubated with the antibiotic for 1 h. When macrophage monolayers were incubated for 1 h with supernatants from tobramycin-treated macrophages subsequent binding of EAG was increased. The supernatants also caused the agglutination of antibody-sensitised erythrocytes. This activity was lost after the supernatants had been absorbed against EAG. It is proposed that the supernatants contain released Fc-receptors and that tobramycin causes an increase in the shedding of Fc-receptors from the macrophage membrane. The mechanism of action of tobramycin and the in vivo relevance of these results is discussed.

Animals↗

PubMedDate not supplied

Identification of oral yeast species isolated from individuals with diabetes mellitus.

In our epidemiological study of 439 patients with diabetes mellitus, the proportion of Candida albicans isolated by the oral rinse technique was 67%. A comparison of the conventional germ tube test with the API 20C Auxanogram kit revealed that 23.6% (129/546) of germ tube-positive species were not identified as C. albicans by the kit. The API 20C Auxanogram therefore underestimated the prevalence of C. albicans. Additionally, a significant number of yeasts (138/1050, 13.1%) isolated from these patients could not be reliably identified by the kit.

Candida↗

PubMedDate not supplied

Cytokine release of whole blood from adult female donors challenged with mistletoe lectin-1 standardised mistletoe extract and E. coli endotoxin or phytohaemagglutinin (PHA).

Cytokine (TNF, alpha, interleukin-6) release of whole blood from healthy donors was challenged with mistletoe extract standardised for mistletoe lectin-1 (sML) and control substances (E. coli endotoxin; phytohaemagglutinin). The rationale of this investigation was non-proven warnings that pro-inflammatory cytokines induce by the application of standardised mistletoe lectins may induce tumor cell proliferation. These investigations provided evidence that non-cytotoxic concentrations of sML did not induced enhanced TNFa or interleukin-6 secretion compared to non-challenged control cells. Cytotoxic concentrations of sML, however, induced significantly higher cytokine levels than the control, obviously due to non-physiological stimuli. Immunomodulation with clinically relevant, low-dose sML incubation did not induce proinflammatory cytokine secretion in vitro.

Adult↗