Serum samples from 429 cancer patients, 82 unpaid blood donors, and 74 paid blood donors were tested for hepatitis C virus (HCV) markers in two commercially available enzyme immunoassays (EIAs). A total of 229 of 429 (53.4%) cancer patients were positive by the two EIAs. A total of 34 of 156 (21.8%) of the blood donors were positive by the EIAs, with a higher prevalence among paid blood donors (20/74; 27%) compared with that among the unpaid blood donors (14 of 82; 17%). EIA-positive sera were tested for confirmation of the results in an immunoblot assay (LiaTek) in which reactivities to four synthetic peptides representing the HCV cure protein and two synthetic peptides representing nonstructural proteins 4 and 5 were measured. Of 243 first and/or second EIA-positive samples from cancer patients, 188 (77.2%) were confirmed to be positive in the synthetic peptide immunoblot. A total of 33 of 35 (94.3%) blood donor samples were confirmed to be positive. A great diversity in reactivity patterns was seen. However, all sera from the group of paid blood donors were exclusively reactive to core peptides 1 and 2. A subset of LiaTek assay-positive samples were tested by the four-antigen RIBA-2 assay. The sera from the paid blood donors were all nonreactive. A subset of the LiaTek-positive sera was analyzed for the presence of the HCV genome by reverse transcriptase-PCR. Eleven of the 20 serum samples with reactivity to LiaTek core peptides 1 and 2 only were HCV reverse transcriptase. PCR positive, as were the majority of the sera with other reactivity patterns by the LiaTek assay. The results confirm the very high prevalence of HCV infection in Egypt. Furthermore, the results indicate that there is circulating in Egypt, particularly in the group of blood donors paid for their donation, an HCV variant which elicits an immune response that is not detected by the RIBA-2 assay.

The dielectric behaviour of unirradiated and irradiated PVB films, using UV radiation, was investigated as a function of temperature and frequency. The results obtained are discussed in terms of the dielectric parameters εmaxH, Δε, β and ΔE. These experimental results, in combination with the temperature dependence of dynamic mechanical measurements in the tensile mode and with d.s.c measurements, show that during UV irradiation of PVB, besides other changes, cross-linking predominates. A mechanism of photodegradation has been proposed and is supported by gel content determination and IR spectra. © 1995.

The dielectric and optical characteristics of a sample of cellulose acetate (DS = 2.45) in dioxane solutions were studied at 10–50°C of concentration 10–50 wt% to include both isotropic and anisotropic phases. The study showed that the loss maximum, εmax″, magnitude of polarization, (ε0 − ε∞), static dielectric constant, ε0, time of relation, (2πfm)−1, and refractive index, nD, steadily increase with concentration up to the critical concentration (41 wt%) and then decrease. The mean‐square dipole moment, 〈gμ2〉, decreases steadily up to the critical concentration then remains nearly constant, indicating that the isotropic solution changes to anisotropic, with smaller mean‐square dipole moment. Comparison between the results of cellulose acetate (CA) and those of hydroxypropyl cellulose (HPC) reveals that, at the critical concentration in dioxane, the cholesteric structure of HPC possesses a greater mean‐square dipole moment with higher temperature coefficient than does CA. The activation energy of the relaxation process for hydroxypropyl cellulose is higher, indicating a greater intrachain interaction compared with cellulose acetate. © 1995 Society of Chemical Industry