Prevalence, genotype distribution and persistence of human papillomavirus in oral mucosa of women: a six-year follow-up study

Background

Human papillomavirus (HPV) infections have been linked to a subset of oral and oropharyngeal cancers. However, little is known on the natural history of oral HPV infections. We designed the prospective Finnish HPV Family Study to assess the dynamics of HPV infections in parents and their infants. This study reports HPV genotype distribution and virus persistence in oral mucosa of the mothers.

Materials and Methods

Totally, 324 pregnant women were enrolled at the 3^rd trimester of pregnancy and followed-up for 6 years. Oral scrapings taken with a brush were collected and HPV-genotyping was performed with nested PCR and Multimetrix® test (Progen, Heidelberg, Germany). The predictors of persistent oral HPV species 7/9 infections were analyzed using generalized estimating equation models.

Results

The point prevalence of oral HPV varied from 15% to 24% during the 6-year follow-up. Altogether, 18 HPV genotypes were identified either as single or multiple-type oral infections. HPV16 was the most prevalent type at 9.7%–18.4%, followed by HPV18, HPV6, and multiple infections. Altogether, 74 women had persistent oral HPV infection determined as at least two consecutive samples positive with the same HPV genotype. HPV16 and HPV6 were the two most frequent types to persist (76% and 9%) for a mean of 18.6 and 20.2 months, respectively, followed by multiple infections (8%) for 18.3 months. An increased risk for persistent oral HPV infection with species 7/9 was associated with being seropositive for low-risk (LR)-HPV-types at baseline, whereas the use of oral contraceptives and a second pregnancy during follow-up were protective. Clinical oral lesions were detected in 17% of these women, one-third of whom had persistent oral HPV-infections.

Conclusion

HPV16 and HPV6 were the most common genotypes in oral HPV-infections and were also most likely to persist. Use of oral contraceptives and a second pregnancy protected against oral HPV persistence.     

Signaling pathways involved in IL-8-dependent activation of adhesion through Mac-1

In human neutrophils, IL-8 induces chemotaxis, the respiratory burst, and granule release, and enhances cellular adhesion, a beta(2) integrin-dependent event. IL-8 stimulates neutrophil adhesion to purified fibrinogen in a Mac-1-dependent manner. Mitogen-activated protein kinase (MAPK) activation was detected in human neutrophil lysates after treatment with IL-8 and PMA, but not the activating mAb CBR LFA 1/2. IL-8-stimulated neutrophil adhesion to fibrinogen was blocked 50% by the MAPK/extracellular signal-related kinase-activating enzyme inhibitor PD098059. Adhesion was blocked approximately 75% by inhibition of the phosphatidylinositol-3 kinase (PI3K) pathway with LY294002, supporting that activation of both MAPK and PI3K may play a role in IL-8-dependent inside-out signals that activate Mac-1. Activation of MAPK was inhibited in IL-8-stimulated cells in the presence of PI3K inhibitors LY294002 or wortmannin, supporting a model in which PI3K is upstream of MAPK. IL-8-stimulated neutrophil adhesion was inhibited 50% by bisindolylmaleimide-I, implicating protein kinase C (PKC) in the intracellular signaling from the IL-8R to Mac-1. A 74-kDa molecular mass species was detected by an activation-specific Ab to PKC when cells were stimulated with PMA or IL-8, but not a beta(2)-activating Ab. Inhibition of either MAPK or PKC resulted in partial inhibition of IL-8-stimulated polymorphonuclear neutrophil adhesion, and treatment with both inhibitors simultaneously completely abolished IL-8-stimulated adhesion to ligand. Inhibition of PI3K blocked MAPK activation, but not PKC activation, suggesting a branch point that precedes PI3K activation. These data suggest that both MAPK and PKC are activated in response to IL-8 stimulation, and that these may represent independent pathways for beta(2) integrin activation in neutrophils.     

Sexing in vitro produced bovine embryos, at different stages of development, using rat H-Y antiserum

The male-specific H-Y antigen is present on mammalian cell membranes and has been identified by various methods, including antiserum cytotoxicity. The objective of the present study was to determine the sex of in vitro produced (IVP) bovine embryos, at varying stages of development, by culturing in the presence of rat monoclonal H-Y antibodies. Embryos derived from IVM/IVF were classified according to the interval after IVF (48, 96 or 120 h) as Category 1, 2 or 3 if they had 4 to 8, <32, and >32 cells, respectively. Embryos of each category were cultured for 24h in TCM-199 supplemented with bovine oviductal epithelial cells, fetal calf serum (FCS), and antibiotics (Control group), to which the following had been added: guinea pig serum (GPS; C' group); H-Y antiserum (HY group); or GPS and H-Y antiserum (C' + HY group). After culture, embryos were designated as "affected" when development was arrested or one or more blastomeres was degenerate; embryos lacking these changes were designated "unaffected." The sex of each embryo was subsequently determined by chromosome analysis. After 48h of IVF (Category 1), within each of the four treatments, the proportion of unaffected embryos was higher than the proportion of unaffected embryos (81% versus 19%, P < 0.05). Similarly, the Control, C' and HY groups of Categories 2 and 3 embryos had different proportions of unaffected versus affected embryos (75% versus 25%, P < 0.05). In all these groups, the male:female ratio did not significantly differ from 1:1. In contrast, in the C' + HY group of Categories 2 and 3 embryos, the ratio of unaffected versus affected embryos was 41% versus 59% (P < 0.05) and the male:female ratio differed (P < 0.05) from the expected 1:1 ratio (approximately 0.3:1 and 4.5:1 for unaffected versus affected, respectively). In conclusion, when bovine embryos were cultured in the presence of rat monoclonal H-Y antibodies and compliment, alterations occurred in embryos that were beyond the 8-cell stage; we inferred that the antibodies cross-reacted with H-Y antigens.     

Structure and Cytopathic Effects of Nelson Bay Virus

A virus isolated from a flying fox (Pteropus poliocephalus) has a morphology similar to that of reoviruses. However, unlike the reoviruses, this virus has a rapid cytopathic effect, causing cell fusion, vacuolization of the cytoplasm, and an unusual nuclear degeneration. Immunofluorescence indicates that viral antigen is distributed through both nucleus and cytoplasm. Viral maturation appears to take place in discrete cytoplasmic factories, and there is no apparent involvement of spindle tubules.     

Microtubule organization during maturation of Xenopus oocytes: assembly and rotation of the meiotic spindles.

Assembly of the meiotic spindles during progesterone-induced maturation of Xenopus oocytes was examined by confocal fluorescence microscopy using anti-tubulin antibodies and by time-lapse confocal microscopy of living oocytes microinjected with fluorescent tubulin. Assembly of a transient microtubule array from a disk-shaped MTOC was observed soon after germinal vesicle breakdown. This MTOC-TMA complex rapidly migrated toward the animal pole, in association with the condensing meiotic chromosomes. Four common stages were observed during the assembly of both M1 and M2 spindles: (1) formation of a compact aggregate of microtubules and chromosomes; (2) reorganization of this aggregate resulting in formation of a short bipolar spindle; (3) an anaphase-B-like elongation of the prometaphase spindle, transversely oriented with respect to the oocyte A-V axis; and (4) rotation of the spindle into alignment with the oocyte axis. The rate of spindle elongation observed in M1 (0.7 microns min-1) was slower than that observed in M2 (1.8 microns min-1). Examination of spindles by immunofluorescence with antitubulin revealed numerous interdigitating microtubules, suggesting that prometaphase elongation of meiotic spindles in Xenopus oocytes results from active sliding of antiparallel microtubules. A substantial number of maturing oocytes formed monopolar microtubule asters during M1, nucleated by hollow spherical MTOCs. These monasters were subsequently observed to develop into bipolar M1 spindles and proceed through meiosis. The results presented define a complex pathway for assembly and rotation of the meiotic spindles during maturation of Xenopus oocytes.     

Self-assembly and photocatalytic activity of branched silicatein/silintaphin filaments decorated with silicatein-synthesized TiO<Subscript>2</Subscript> nanoparticles

The fundamental mechanisms of biomineralization and their translation into innovative synthetic approaches have yielded promising perspectives for the fabrication of biomimetic and bioinspired organic–inorganic hybrid materials. In siliceous sponges, the enzyme silicatein catalyzes the polycondensation of molecular precursors to nano-structured SiO₂ that is deposited on self-assembled filaments consisting of the two silicatein isoforms (silicatein-α and -β) and the scaffold protein silintaphin-1. Due to its broad substrate specificity silicatein is also able to convert in vitro various other precursors to non-biogenic materials (e.g., hydrolysis of titanium bis(ammonium lactato)-dihydroxide [TiBALDH] and subsequent polycondensation to titania [TiO₂]). In the present approach, silicatein was bioengineered to carry a protein tag (Arg-tag) that confers binding affinity to TiO₂. Then, by combining Arg-tagged silicatein-α with silicatein-β and silintaphin-1, self-assembled branched hybrid protein microfilaments were fabricated. Upon subsequent incubation with TiBALDH the filaments were decorated with TiO₂ and assayed for photocatalytic activity through photodegradation of the dye methylene blue. This is the first approach that considers concomitant application of two silicatein isoforms for the synthesis of bioinspired organic–inorganic hybrid materials. It is also the first time that the biocatalytic activity of the enzymes has been combined with both the structure-providing properties of silintaphin-1 and a TiO₂ affinity protein tag to fabricate self-assembled branched protein filaments as template for a silicatein-synthesized TiO₂ photocatalyst. The TiO₂-decorated filaments might be explored as a practical alternative to approaches where biotemplates have to be laboriously isolated from their original biological source prior to TiO₂ immobilization.     

Collagen degradation by superoxide anion in pulse and gamma radiolysis

Delipidated collagen fibrils reconstituted from acid-soluble calf skin collagen, suspended in 50 mM phosphate buffer, pH 7.4, containing 100 mM sodium formate, were submitted to pulse radiolysis in Febetron devices or to gamma radiolysis in a 60Co irradiator. A collagen degradation process was found. The kinetics of this degradation was followed by evaluation of the amount of 4-hydroxyproline present in the small peptides liberated during the irradiation period. The yield of 4-hydroxyproline small peptides was low (0.1 mol/100 eV for an initial collagen concentration 3.2 microM). It increased linearly with the dose of irradiation and the concentration of collagen in suspension. The kinetic competition between O2-. dismutation and O2-. reaction with collagen was studied by pulse radiolysis at several concentrations of collagen. A value of the kinetic constant of k(O2-. + collagen) = 4.8 . 10(6) mol-1.l.s-1 was determined.     

The geographic distribution of the ACE II genotype: a novel finding

Angiotensin converting enzyme (ACE) gene polymorphism insertion (I) or deletion (D) has been widely studied in different populations, and linked to various functional effects and associated with common diseases. The purpose of the present study was to investigate the relationship between the ACE I/D frequency in different populations and geographic location; ACE I/D allele frequency in the Lebanese population and ACE II genotype contribution to the geographic trend were also identified. Five hundred and seventy healthy volunteers were recruited from the Lebanese population. Genomic DNA was extracted from buccal cells, and amplified by polymerase chain reaction; products were then identified by gel electrophoresis. The frequencies of the different ACE I/D genotypes were determined and tested for Hardy-Weinberg equilibrium (HWE). To assess the relationship between ACE I/D frequency and geographic location, and to identify how the Lebanese population contributes to the geographic trend in ACE I/D frequencies, Eurasian population samples and Asians were incorporated in the analyses from the literature. The frequency of the I allele in the Lebanese population was 27% and the corresponding II genotype was at a frequency of 7.37% (in HWE; P=0.979). The ACE I allele and genotype frequencies show an association with longitude, with frequencies increasing eastwards and westwards from the Middle East.