Detection of specific IgE antibodies in sera from patients with hydatidosis.

A simple and sensitive immunoenzymatic assay for detection of specific IgE in hydatid disease is presented. Sera from 43 patients with hydatidosis, eight with schistosomiasis, two with taeniasis, two with cancer and 16 healthy blood donors were tested by both the immunoenzymatic technique and the classical radioallergosorbent test. Data were analysed in terms of different sensitivity and specificity of the two methods. The results indicate that the enzymatic method performed in microplates is as sensitive as the radioimmunological one (77% of positivity for both the tests), but the latter suffers from an higher rate of false positive reactions with sera from patients with other helminthic diseases (80% vs 20%). When the specific IgE evaluation is compared with other classical serological techniques, such as indirect haemagglutination and double diffusion in terms of different sensitivity in revealing an anti-Echinococcus immunological reactivity, the results suggest that specific IgE evaluation represents a useful addition to the classical serodiagnostic tests.

Modifications of gamma-ray sensitivity of bacterial membrane by pre-exposure to light.

The exposure of E.coli B/r cells to ultraviolet (UV) or to visible light prior to irradiation with gamma-rays modifies the sensitivity of the cell membrane to the radiation damage responsible for the loss of intracellular K+ content. The experiments reported in the paper have shown: 1. exposure of bacterial cells to sublethal doses of UV light increases their sensitivity to gamma-ray-induced membrane damage, while exposure to visible light has the opposite effect; 2. in combined exposures, the visible light, either given before or after the UV always produces a strong photoprotective effect. In either case, the photosensitizing effect of UV is completely suppressed; 3. the photoprotection decays with time if cell suspensions are left in the dark before gamma-irradiation. At 0 degrees C, the half-life of the photoprotective effect is 25 min at pH 7 and 100 min at pH 7.5. The decay is due to the presence of oxygen; 4. the light band responsible for the induction of photoprotection has been estimated to lie in the wavelength region between 540 and 580 nm.