Thirty surgical samples of squamous cell carcinoma of the cervix obtained from Chinese women were analysed for the presence of human papillomavirus (HPV) types 16 and 18 using Southern blot hybridization procedure. HPV16 was detected in 53% while HPV18 was found in only 6% of the samples analyzed. When compared with other reports, variation in the geographic distribution of these two HPV types in association with cervical carcinoma is noted. Thirty-seven and a half percent of the HPV16-positive samples contained this HPV type in episomal form and an equal number in cellular DNA-integrated form. The simultaneous presence of both episomal and integrated forms was found in the remaining 25% of the positive samples. The two HPV18-positive cases harbored only episomal viral genome and were not superinfected by HPV16. Analysis of the HPV16 integration samples showed that single integration events had probably occurred and some of the viral sequences had been lost on or subsequent to integration.

Two antimicrobial P-113 peptide derivatives, P-113Du and P-113Tri, were investigated in this study. Notably, P-113Du and P-113Tri contained significant fractions of ␣-helix conformation and were less sensitive to high salt and low pH than P-113. Moreover, compared to P-113, these peptides exhibited increased antifungal activity against planktonic cells, biofilm cells, and clinical isolates of Candida albicans and non-albicans Candida spp. These results suggest that P-113Du and P-113Tri are promising candidates for development as novel antifungal agents. Histatin 5 (Hst5) is a potent antimicrobial peptide (AMP) with activity against Candida albicans (1). A 12-mer amino acid fragment of Hst5, P-113, retains strong candidacidal activity compared to the parental Hst5 and has had no adverse effects in clinical trials (2-6). P-113 forms an amphipathic ␣-helix in trifluoroethanol, which mimics the hydrophobic environment of microbial membranes (7). However, the interaction between AMPs and microbial membranes is salt sensitive (8, 9). The efficacy of P-113 is significantly reduced in the presence of high salt concentrations, such as 150 mM sodium chloride or 100 mM sodium phosphate (4, 10).To improve the activity of P-113, our approach was based on the dimerization of histatin-derived peptides to increase bactericidal activity against Staphylococcus aureus (11). In this study, the duplicated and triplicated P-113 (designated P-113Du and P-113Tri, respectively) ( Table 1) were characterized. The secondary structures of the peptides in 85% trifluoroethanol (pH 6.0) were analyzed using an AVIV circular dichroism spectrometer at 25°C. Spectra were measured from 195 to 260 nm at 1-nm intervals, and mean residue molar ellipticity (MRE) was used to compare different peptides. Figure 1 shows an ␣-helical conformation characterized by a strong positive band at 195 nm and two negative bands at 208 and approximately 222 nm (12). The ␣-helical content of P-113 was estimated to be 2.9% using the ␤-structure selection (BeStSel) method (13). However, the ␣-helical contents of P-113Du and P-113Tri were 10.6% and 21.4%, respectively, suggesting the presence of a significant fraction of ␣-helix conformation.To examine the salt sensitivity of the peptides, spot assays were performed ( Fig. 2A). Cells (4.0 ϫ 10 5 cells) of the C. albicans strain SC5314 were incubated with different concentrations of sodium acetate (NaOAc) and peptides for 1 h. The mixtures were then spotted onto 1% yeast extract-2% peptone-2% glucose (YPD) agar. After 24 h of incubation, P-113 exhibited candidacidal activity in the presence of 12.5 mM sodium acetate but reduced activity in the presence of 62.25 and 93.75 mM salt. However, P-113Du and P-113Tri exhibited potent candidacidal activity even in the presence of 93.75 mM sodium acetate ( Fig. 2A). In addition, a previous study indicated that P-113 loses its bactericidal activity at pH 4.5 (14). Therefore, the pH sensitivities of the peptides were examined. P-113 exhibited candidacidal activity at pH 6 and 8, and...