Dermatological testing of an improved apertured film surface for feminine hygiene pads.

CONTEXT: Apertured polyethylene films (AF) have been used as a surface for sanitary pads for decades because they are compatible with the skin and keep the pad surface drier. A modified film (AF-plus) with improved fluid handling and a smoother, suppler texture has been developed. We hypothesized that these changes would improve both performance and skin compatibility. However, distinguishing the skin effects of materials that are inherently mild is a challenge. OBJECTIVES: (i) To compare the skin irritation potential of pads with AF-plus modified film relative to the standard AF film and (ii) to assess the potential for the AF-plus film to induce delayed contact hypersensitivity. MATERIALS AND METHODS: Pads bearing the AF-plus film were compared to pads with the standard AF film in a behind-the-knee (BTK) test, which assesses the combination of chemical irritation and frictional effects of materials applied to the popliteal fossa under a semi-occlusive bandage. Erythema on the skin surface was scored with the naked eye and subsurface tissue erythema was visualized and scored using cross-polarized illumination. Skin dryness was scored with the naked eye only. One-sided statistical evaluations were performed to test the hypothesis of AF-plus film superiority. The potential of the AF-plus film to induce delayed contact hypersensitivity was assessed by a human repeat insult patch test (HRIPT). RESULTS: Pads with the AF-plus surface were significantly milder to skin in the BTK test, producing lower levels of both surface and subsurface tissue erythema. Moreover, subjects with preexisting erythema on the skin surface at study start developed comparatively less erythema over the course of the study overall with the AF-plus pad compared to the AF pad. No significant difference in skin dryness was observed between product groups. The AF-plus pad showed no evidence of inducing delayed contact hypersensitivity. CONCLUSIONS: The AF-plus pad was superior to the AF pad in terms of skin mildness as discerned by objectively scored surface and subsurface tissue erythema. In subjects with preexisting erythema, the AF-plus pad appeared to contribute less to the further development of inflammation under the test conditions. Given the compositional similarities in the two films, the results could point to more limited contribution of the AF-plus film to skin friction, one of the factors simulated by the BTK test protocol.

Comparison of TaqMan real-time PCR and p24 Elisa for quantification of in vitro HIV-1 replication.

In this study, TaqMan PCR was used to assess viral replication of HIV-1 infected cells in vitro. This PCR technique was compared with p24 ELISA as a standard method to monitor HIV-1 replication in cell culture. Hut78 T-lymphoblastoid cells were infected with different titres of HIV-1(IIIb) (MOI 0.05-0.0005). The course of HIV-1 replication was monitored by determination of p24 concentrations by ELISA in cell culture supernatants and by quantitation of HIV-1 gag RNA by TaqMan RT-PCR. Additionally, the number of HIV-1 proviral copies was assessed by TaqMan PCR. Monitoring of HIV-1 replication by p24 ELISA and TaqMan RT-PCR revealed comparable kinetics of infection. Both methods provided similar data on the exponential increase and on plateauing of HIV-1 replication. Furthermore, both methods were equally sensitive. However, a 7 log linearity of TaqMan HIV-1 gag PCR was demonstrated without dilution of the specimen, in contrast to p24 ELISA, where because of its narrow range of detectable p24 concentrations, sample dilution was necessary. Although determination of the number of proviral copies by TaqMan PCR does not measure HIV-1 replication, the kinetics of proviral copy number following in vitro inoculation of cells with HIV-1 was nearly the same as the kinetics of HIV-1 RNA copy numbers. In conclusion, TaqMan real-time RT-PCR was demonstrated as a reliable and sensitive tool to quantify and monitor HIV-1 replication in cell culture. It is suggested, therefore, that this technique be an alternative method to monitor HIV-1 replication in vitro.

Identification and characterization of a highly efficient anti-HIV pol hammerhead ribozyme.

The aim of this study was to identify and to characterize a highly active anti-HIV ribozyme. Therefore, the genome of HIV-1 IIIb was screened for not yet addressed GUC triplets within highly conserved sequences. Here we report the in vitro characteristics and the antiviral activity of the fittest identified anti-HIV hammerhead ribozyme, targeting the 13th GUC triplet within the HIV-1 pol gene (HHPol13). Multiple turnover kinetics were determined in vitro and revealed very promising kinetic data: V(max) = 39 nM/minute, K(m) = 576 nM, k(cat) = 3.9/minute, and K(cat)/K(m) = 6.8/minute/microM. To analyze its antiviral activity the hammerhead ribozyme was expressed retrovirally in Hut78 cells followed by HIV-1 infection. The newly identified ribozyme conferred a long-term inhibition of HIV-1 replication until the end of the observation period at day 56. We were able to demonstrate that the antiviral activity was mainly due to a ribozyme effect combined with a limited antisense activity. Additionally, the effect of the identified ribozyme was compared with a retrovirally expressed siRNA directed against the same target in the HIV-1 pol gene. This siRNA (siPol13) showed no inhibition of HIV replication. In summary, the hammerhead ribozyme HHPol13 was demonstrated to confer superior cleavage and antiviral activity against HIV-1. These results suggest that even in the RNAi era ribozymes still have the potential as highly active antiviral agents.