Divalent cation-mediated epithelial union with connective tissue

Ex vivo comparison of microbicide efficacies for preventing HIV-1 genomic integration in intraepithelial vaginal cells

Vaginally applied microbicides hold promise as a strategy to prevent sexual HIV transmission. Several nonspecific microbicides, including the polyanion cellulose sulfate, have been evaluated in large-scale clinical trials but have failed to show significant efficacy. These findings have prompted a renewed search for preclinical testing systems that can predict negative outcomes of microbicide trials. Moreover, the pipeline of potential topical microbicides has been expanded to include antiretroviral agents, such as reverse transcriptase, fusion, and integrase inhibitors. Using a novel ex vivo model of vaginal HIV-1 infection, we compared the prophylactic potentials of two forms of the fusion inhibitor T-20, the CCR5 antagonist TAK-778, the integrase inhibitor 118-D-24, and cellulose sulfate (Ushercell). The T-20 peptide with free N- and C-terminal amino acids was the most efficacious compound, causing significantly greater inhibition of viral genomic integration in intraepithelial vaginal leukocytes, measured by an optimized real-time PCR assay, than the more water-soluble N-acetylated T-20 peptide (Fuzeon) (50% inhibitory concentration [IC50], 0.153 microM versus 51.2 microM [0.687 ng/ml versus 230 ng/ml]; P<0.0001). In contrast, no significant difference in IC50s was noted in peripheral blood cells (IC50, 13.58 microM versus 7.57 microM [61 ng/ml versus 34 ng/ml]; P=0.0614). Cellulose sulfate was the least effective of all the compounds tested (IC50, 1.8 microg/ml). These results highlight the merit of our model for screening the mucosal efficacies of novel microbicides and their formulations and potentially rank ordering candidates for clinical evaluation.

Behavior of hyaluronic acid from gingival epithelium and connective tissue on the analytical ultracentrifuge

The molecular weights of hyaluronic acid (HA) isolated from separated specimens of human gingival epithelium and connective tissue as well as standard hyaluronic acid preparations have been estimated. The values were determined following substitution of sedimentation values into a previously determined empirical relationship between the reciprocal of the sedimentation coefficient at zero concentration (S-1)0 and molecular weights estimated by sedimentation-diffusion (MsD). The values of (S-1)0 for connective tissue and standard low-molecular weight HA preparations obtained by linear regression of all points indicated molecular weights (MsD) of 340,000 and 205,000 respectively. However, epithelial and standard high-molecular weight HA behaved differently during ultracentrifugation generating a curvilinear relationship between s-1 and concentration. Nevertheless linear extrapolation of a line of best fit of the very lowest concentrations (those which approached zero concentration) provided molecular weight estimates of 860,000 and 2,500,000 respectively. Moreover, similar treatment of s-1 values derived from the previously published data of Laurent, Ryan and Pietruszkiewicz has validated the use of linear regression of s-1 at the lower concentrations alone, to calculate high-molecular weight HA. The curvilinear relationship for s-1 throughout the whole concentration range (0.15-2.3 mg/ml) has been regarded only as a qualitative indication that the HA samples are of relatively high-molecular weight, while a straight line through such data points implies a qualitatively lower molecular weight for HA.

Ultrastructural alteration of trypsin- and pancreatin-separated embryonic rabbit palate epithelium and mesenchyme

The effects of 30- and 45-minute trypsin- and pancreatin-separation on embryonic rabbit palate epithelium and mesenchyme were studied with the electron microscope. Changes in epithelium included fragmentation of the basal lamina and formation of cytoplasmic blebs associated with the basal cell layer. Changes in mesenchymal cells were first evident at 45 min of incubation and included cell fragmentation, nuclear pyknosis, and dilation of extracellular space. Results indicate a differential susceptibility of mesenchyme to the separating agent.