The possibility of clinical bonding between metal/ceramic brackets to zirconia: in vitro study

Objective: The present study aimed to assess the bond strength and durability of six bonding agents concerning their application to metal or ceramic brackets and zirconia. Materials and Methods: Six resin cement bonding agents (XT, XTS, RSBU, RGBU, SBPM, and GMP) were chosen for this investigation. Specimens were either stored in distilled water at 37°C for 24 h or subjected to 5,000 thermocycles before conducting a Shear Bond Strength (SBS) test. Statistical analysis of the SBS data was performed using three-way ANOVA and Games-Howell tests (α = 0.05). The Adhesive Remnant Index was examined, and the debonding surface details on brackets and zirconia were observed. Results: For metal brackets, all groups demonstrated clinically acceptable bond strength, irrespective of storage conditions, except for the XT group. Regarding ceramic brackets, all groups displayed acceptable bond strength after 24 h of water storage. However, following thermocycling, a significant decrease in SBS was noted across all groups (p < 0.05), with SBPM exhibiting a higher bond strength. Three-way ANOVA analysis indicated that SBS values were notably influenced by each factor, and an interaction among the three independent variables was observed (p = 0.000). Conclusion: The reliable bond strength between ceramic brackets and zirconia was significantly lower after thermocycling compared to that of metal brackets and zirconia. SBPM exhibited consistent and robust bond strength between ceramic/metal brackets and zirconia across various storage conditions. Furthermore, the HEMA-free adhesive demonstrated a potentially more consistent bonding performance compared to the HEMA-containing adhesive employed in this study.

Antibacterial performance of a porous Cu-bearing titanium alloy by laser additive manufacturing

Porphyromonas gingivalis (P. gingivalis) is the most common species that causes peri-implantitis. It forms an irreversible dense biofilm and causes inflammation. A novel 3D-printed porous TC4-6Cu alloy was fabricated using selective laser melting (SLM) technology for the dental implant, which is anticipated to inhibit biofilm formation. We attempted to investigate the antibacterial ability and antibacterial mechanism of the 3D-printed porous TC4-6Cu alloy against P. gingivalis. This work used scanning electron microscopy (SEM) and laser confocal microscopy (CLSM) to detect the antimicrobial ability of the alloy against sessile P. gingivalis. The results indicated that the 3D-printed porous TC4-6Cu alloy could cause bacterial fragmentation and deformation. Plate antimicrobial counting experiments showed that the antibacterial rates of the alloy against adherent bacteria and planktonic bacteria after 24 h were 98.05% and 73.92%, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Cu2+ were tested to appraise the antibacterial property of the alloy against planktonic P. gingivalis. The relationship between the antibacterial mechanism of the alloy with oxidative stress was evaluated through ROS fluorescence intensity and protein leakage concentration. The results revealed that the alloy significantly eliminated adherent bacteria and inhibited biofilm formation. Moreover, 3D-printed porous TC4-6Cu alloy demonstrated significant bactericidal ability by inducing the production of reactive oxygen species (ROS), which could result in protein leakage from the bacterial cell membrane. This research may open a new perspective on the development and biomedical applications for dental implantation.

Preoperative prediction and histological stratification of intracranial solitary fibrous tumours by machine-learning models

AIM

To explore the effectiveness and feasibility of machine-learning models based on magnetic resonance imaging (MRI) radiomics features in differentiating intracranial solitary fibrous tumour (ISFT) from angiomatous meningioma (AM) and stratifying ISFT histologically.

MATERIALS AND METHODS

This study retrospectively recruited 268 patients with a histological diagnosis of ISFT (n=120) or AM (n=148), and 116 of the ISFT patients were used for stratified analysis of histological grade. The radiomics features were extracted from axial T1-weighted imaging (WI), T2WI and contrast-enhanced T1WI sequences. All patients were assigned randomly to the training group and test group in a ratio of 7:3. The models were optimised by 10-fold cross-validation in the training group, and the independent test group was used for further testing of the models. The performances of machine-learning models based on radiomics, clinical, and fusion features in predicting and stratifying ISFT were evaluated.

RESULTS

ISFT and AM differed significantly in terms of age, tumour shape, enhancement pattern, and margin. There was no significant difference in the clinical characteristics between World Health Organization (WHO) grade II and WHO grade III ISFT. When used to differentiate ISFT from AM, the area under the curve (AUC) values of the machine-learning models based on radiomics, clinical, and fusion features in the test group were 0.917, 0.923 and 0.950, respectively. When used for histological stratification of ISFT, the model based on the radiomics signature achieved an AUC value of 0.786 in the test group.

CONCLUSIONS

Machine-learning models can contribute in the prediction and histological stratification of ISFT non-invasively, which can help clinical differential diagnosis and treatment decisions.

The color stability, water sorption, and solubility of ten composite resins

OBJECTIVES

This study aims to evaluate the color stability and related properties including water sorption and solubility of ten light-cured composite resins in different solutions.

METHODS

A total of 10 composite resins were BeautifilⅡ(B2) and Ceram. X One Universal (CXU), Charisma (CS), Charisma Diamond (CD), Denfil (DF), DX. Universal (DXU), Filtek Z250 (Z250), Filtek Z350 XT (Z350), FS-1 (FS), and Magnafill Putty (MP). Meanwhile, a total of 20 disk-shaped samples were fabricated and randomly divided into four groups (n=5), which were immersed in distilled water (control group), curry, coffee, and red wine for 28 days. The color (CIE L∗a∗b∗) was measured by a spectrophotometer at baseline and 1, 7, 14, 21, and 28 days after immersion, and the color differences were calculated. Water sorption and solubility values were measured ba-sed on ISO 4049: 2019. In addition, three-way ANOVA was used to evaluate the influence of resin materials, solutions, and immersion time on discoloration results, meanwhile, one-way ANOVA was used to compare the water sorption values and solubility values of different materials.

RESULTS

All samples showed a certain degree of color change with time. Color differences were significantly influenced by materials, solutions, and immersion time (P<0.001). The color changes of the measured materials at any time point: curry>red wine>coffee>distilled water. Thus, all materials showed clinically unacceptable discoloration (ΔE>3.3) after immersing in staining curry, coffee, and red wine for 7 days. Therefore, when immersed in curry for 28 days, CS and DXU had the smallest and the largest color difference. In addition, when immersed in coffee for 28 days, FS showed the smallest color change and DXU showed the largest. Moreover, when immersed in red wine for 28 days, FS showed the smallest color change and Z350 showed the largest. Furthermore, MP and CXU had small color differences in all solutions. Meanwhile, Z350 had the highest water sorption and MP had the lowest. The solubility values of CS and CD were significantly higher than those of other materials.

CONCLUSIONS

The color stability of light-cured composite resin is materials-depended and affected by pigment types and immersion time. Thus, MP and CXU have better color stability. MP has low water sorption.

Evaluation of the Color Stability, Water Sorption, and Solubility of Current Resin Composites

This study aims to assess the color stability, water sorption, and solubility of 11 resin composites as commercially available dental products. Twenty samples (10 mm in diameter and 2 mm in thickness) of each material were fabricated using a customized silicone mold, followed by immersion in each of curry, coffee, wine, and distilled water for 28 days (n = 5). Baseline shade and color changes (ΔE) were measured using a reflection spectrophotometer. The CIE L*, a*, b* system was used to evaluate the color changes. Five samples of each resin composite were applied to test water sorption and solubility according to ISO 4049:2009. As a result, the ∆E values were significantly influenced by each of the three factors (composition of material, solution, time) and the interactions between them (p < 0.001). Highest resistance to discoloration was achieved by Ceram.X One Universal (CXU), followed by Magnafill Putty (MP). Generally, microhybrid composites showed fewer color changes than nanohybrid composites and giomers. DX. Universal and Filtek Z350 XT showed the highest ΔE values in all colorants. All materials tested in this study fulfilled the criteria of ISO 4049:2009; CXU and MP had the lowest water sorption and solubility. The Pearson test showed statistically significant positive correlations between water sorption and ΔE and between solubility and ΔE.

Shear bond strength of different bonding agents to orthodontic metal bracket and zirconia

This study aimed to evaluate the shear bond strength (SBS) of four bonding agents used to bond metal brackets to zirconia under different storage conditions. Four bonding agents were used [FLC: (Fuji ORTHO LC), XT: (Transbond^TM XT), RUC-SBU: (Rely X^TM Ultimate Clicker Adhesive Resin Cement+Single Bond Universal), and RUC-GBU: (Rely X^TM Ultimate Clicker Adhesive Resin Cement+Gluma Bond Universal)] to bond two types of metal brackets (PT/3M) to zirconia surfaces, and they were stored in water at 37ºC for 24 h or thermocycling for 3,000 cycles. The SBS data of RUC-SBU and RUC-GBU using PT brackets were significantly higher than those of 3M brackets before and after thermocycling. It could be concluded that RUC-SBU and RUC-GBU could offer sufficient bond strength between metal brackets and zirconia for the short term compared with FLC and XT. The design of brackets can significantly affect the bond strength to zirconia.

Biodegradability and Cytocompatibility of 3D-Printed Mg-Ti Interpenetrating Phase Composites

Orthopedic hybrid implants combining both titanium (Ti) and magnesium (Mg) have gained wide attraction nowadays. However, it still remains a huge challenge in the fabrication of Mg-Ti composites because of the different temperatures of Ti melting point and pure Mg volatilization point. In this study, we successfully fabricated a new Mg-Ti composite with bi-continuous interpenetrating phase architecture by infiltrating Mg melt into Ti scaffolds, which were prepared by 3D printing and subsequent acid treatment. We attempted to understand the 7-day degradation process of the Mg-Ti composite and examine the different Mg2+ concentration composite impacts on the MC3T3-E1 cells, including toxicity, morphology, apoptosis, and osteogenic activity. CCK-8 results indicated cytotoxicity and absence of the Mg-Ti composite during 7-day degradation. Moreover, the composite significantly improved the morphology, reduced the apoptosis rate, and enhanced the osteogenic activity of MC3T3-E1 cells. The favorable impacts might be attributed to the appropriate Mg2+ concentration of the extracts. The results on varying Mg2+ concentration tests indicated that Mg2+ showed no cell adverse effect under 10-mM concentration. The 8-mM group exhibited the best cell morphology, minimum apoptosis rate, and maximum osteogenic activity. This work may open a new perspective on the development and biomedical applications for Mg-Ti composites.

Bone density in youth with prediabetes: results from the National Health and Nutrition Examination Survey, 2005-2006

Youth with type 2 diabetes might have suboptimal peak bone mass, but it is unknown whether similar effects are evident in youth with prediabetes. Results from this study suggest that diabetes-related effects on peak bone mass likely occur before disease onset, and involve the muscle-bone unit.

INTRODUCTION

Type 2 diabetes might adversely influence bone health around the age of peak bone mass, but it is unknown whether diabetes-related effects on areal bone mineral density (aBMD) are evident in youth with prediabetes. We compared age-related trends in aBMD and associations between lean body mass (LBM) and aBMD between children and adolescents with prediabetes vs. normal glucose regulation.

METHODS

Cross-sectional analysis of data from the National Health and Nutrition Examination Survey (2005-2006) in youth ages 12-20 years (49% female, 34% black) with prediabetes (n = 267) and normal glucose regulation (n = 1664). Whole body aBMD and LBM were assessed via DXA. LBM index (LBMI) and Z-scores for aBMD and LBMI were computed.

RESULTS

Unadjusted between-group comparisons revealed greater mean weight and LBMI Z-scores in youth with prediabetes vs. normal glucose regulation, but similar bone Z-scores between the two groups. While accounting for differences in BMI Z-score, there was a significant interaction between prediabetes status and age with respect to whole body aBMD Z-score (P < 0.05), such that children with prediabetes tended to have increased aBMD but adolescents and young adults with prediabetes tended have lower aBMD. Furthermore, the positive association between LBMI and whole body aBMD was moderated in youth with prediabetes (P < 0.001), who had slightly lower whole body aBMD for a given LBMI (P = 0.068). Lumbar spine bone measures did not differ between the two groups.

CONCLUSIONS

Type 2 diabetes-related threats to peak bone mass might occur prior to disease onset, therefore potentially impacting a considerable proportion of US youth.

Roles of the HGF/Met signaling in head and neck squamous cell carcinoma: Focus on tumor immunity (Review)

c‑mesenchymal‑epithelial transition (Met) is a transmembrane tyrosine kinase receptor of hepatocyte growth factor (HGF). HGF/Met signaling stimulates numerous pathways, including the Ras/mitogenactivated protein kinase (MAPK), phosphatidylinositol 3‑kinase/protein kinase B and Wnt/β‑catenin pathways, which serve important roles in cell proliferation, survival, motility, invasion and angiogenesis, and promotes the development and progression of tumors. Aberrant HGF/Met signaling is associated with a poor prognosis in several types of tumors, including head and neck squamous cell carcinoma (HNSCC). Although, the HGF/MET pathway and HGF and/or Met inhibitors have been extensively reviewed, their role in tumor immunity remains elusive. The present review article summarizes the findings on the HGF/Met signaling in HNSCC, including gene and protein alterations, biological functions and patient outcomes. Furthermore, the role of HGF/Met in tumor immunity is discussed and the controversial association between the expression of HGF/Met and the prognosis of patients with HNSCC from the perspective of tumor immunity is clarified. Ultimately, the present review proposes a clinical approach that may improve the efficacy of Met therapy for HNSCC, namely the intratumoral administration of Met inhibitors in order to reduce the inhibitory effect on immune cell recruitment. However, further studies are required to provide an improved understanding of the effects of the HGF/Met pathway on the tumor microenvironment, and the effects of HGF and Met inhibitors on immune cells in the tumor environment should be the focus of future studies.

Effect of air-blowing temperature and water storage time on the bond strength of five universal adhesive systems to dentin

The purpose of this study was to evaluate the air-blowing temperature and water storage time on the micro-tensile bond strength (μTBS) of five universal adhesive systems to dentin. The bond strength with two different air-blowing temperatures (60±2ºC and 23±2ºC) was measured after water storage at 37ºC for 24 h and 100 days respectively. The fracture surface on dentin side was observed by scanning electron microscope (SEM). Three-way ANOVA revealed a significant effect of universal system (p<0.001) and air-blowing temperature (p<0.001) on bond strength to dentin except water-storage time (p=0.145). The interaction within three factors was significantly different (p<0.001). It could be concluded that the μTBS of universal systems to dentin was material-depended. The higher and more stable bonding performance of universal systems on dentin could be achieved by air-blowing at 60±2ºC temperature. In addition, the quantity of voids in the adhesive layer of aceton-based universal adhesive was significantly reduced by higher temperature.

Patients' expectation and satisfaction with complete denture before and after the therapy

BACKGROUND/AIM

Difficulties in the acceptance of dentures are multifactorial including psychosocial ones. It is questionable whether the patients' satisfaction depends only on the complete denture therapy characteristics. The aim of the study was to evaluated patients' expectation and satisfaction with complete dentures before and after the treatment concerning phonetics, chewing, comfort of use and aesthetics.

METHODS

Forty complete edentulous patients rated their expectation before and satisfaction after the treatment based on a questionnaire scores. Patient-related variables regarding age, gender and previous experience (whether worn complete denture or not) were also recorded.

RESULTS

Patients' rating for expectations were higher than the satisfaction after treatment regarding phonetics, chewing, comfort of use and aesthetics. A negative significant correlation was shown between the items before and after the treatment rating for phonetics, chewing, comfort of use and aesthetics. No statistical correlation was found between all the evaluated aspects' (i.e., phonetics, chewing, comfort of use and aesthetics) of expectation and satisfaction, and age, gender, and previous experience except a weak negative correlation noticed between age and comfort of denture use.

CONCLUSION

Patients' expectations ratings significantly exceeded their satisfactions. Expectations and satisfaction ratings were irrespective of gender and patients previous experience.

miR-199a impairs autophagy and induces cardiac hypertrophy through mTOR activation

Basal autophagy is tightly regulated by transcriptional and epigenetic factors to maintain cellular homeostasis. Dysregulation of cardiac autophagy is associated with heart diseases, including cardiac hypertrophy, but the mechanism governing cardiac autophagy is rarely identified. To analyze the in vivo function of miR-199a in cardiac autophagy and cardiac hypertrophy, we generated cardiac-specific miR-199a transgenic mice and showed that overexpression of miR-199a was sufficient to inhibit cardiomyocyte autophagy and induce cardiac hypertrophy in vivo. miR-199a impaired cardiomyocyte autophagy in a cell-autonomous manner by targeting glycogen synthase kinase 3β (GSK3β)/mammalian target of rapamycin (mTOR) complex signaling. Overexpression of autophagy related gene 5 (Atg5) attenuated the hypertrophic effects of miR-199a overexpression on cardiomyocytes, and activation of autophagy using rapamycin was sufficient to restore cardiac autophagy and decrease cardiac hypertrophy in miR-199a transgenic mice. These results reveal a novel role of miR-199a as a key regulator of cardiac autophagy, suggesting that targeting miRNAs controlling autophagy as a potential therapeutic strategy for cardiac disease.

Evaluation of psychological guidance impact on complete denture wearer's satisfaction

The purpose of this study was to evaluate the impact of psychological intervention on edentulous patients' satisfaction with complete clinically satisfactory complete dentures. The survey was conducted in China Medical University involving 84 individuals receiving complete dentures at this institution from August 2013 to March 2014. Participants were randomly allocated to intervention and control groups consisting of 42 subjects, respectively. In the intervention group, individuals received oral health education and psychological intervention before and after the whole process. In the control group, 42 cases received doctor's regular advice after treatment. Satisfaction regarding aesthetic, speech, mastication, retention and comfort was rated in the first and third month after prosthesis treatment. Patients overall aesthetic, speech, mastication and retention were significantly improved in both intervention and control groups in 3 months later after prosthesis treatment when compared with the first month (P < 0·05). No significant difference existed for comfort in control group. Patient scores on aesthetic, speech, mastication and retention at both first and third month evaluations (P < 0·05) differed between the control and intervention groups. However, there was no difference for their scores related to comfort (P > 0·05) in first and third month. The study concludes that psychological intervention plays a significant role in improving patient satisfaction with complete dentures.

[Effect of preparation methods on the metal-porcelain bond strength of Co-Cr alloys]

OBJECTIVE

To compare the shear bond strength(SBS) of cast Co-Cr alloys and selective laser melting(SLM) Co-Cr alloys with those of dental porcelain.

METHODS

A dental porcelain (Vita) was applied on cast and SLM Co-Cr alloy specimens (n = 10). SBS test was conducted, and fracture mode analysis was determined. Student's t-test by SPSS 13.0 software was employed to analyze the data.

RESULTS

The SLM Co-Cr alloy specimens had lower SBS values than the cast Co-Cr alloy specimens (P > 0.05). The metal-porcelain bond strength value of the cast group was (33.11 +/- 4.98) MPa, and that of the SLM group was (30.94 +/- 5.98) MPa. The specimens in both test groups exhibited mixed failure.

CONCLUSION

The metal-porcelain system processed by SLM exhibit a bond strength that is similar to that of the cast group. This system also display a high precision.

[Effect of preparation methods on the metal-porcelain bond strength of Co-Cr alloys]

OBJECTIVE

To compare the shear bond strength(SBS) of cast Co-Cr alloys and selective laser melting(SLM) Co-Cr alloys with those of dental porcelain.

METHODS

A dental porcelain (Vita) was applied on cast and SLM Co-Cr alloy specimens (n = 10). SBS test was conducted, and fracture mode analysis was determined. Student's t-test by SPSS 13.0 software was employed to analyze the data.

RESULTS

The SLM Co-Cr alloy specimens had lower SBS values than the cast Co-Cr alloy specimens (P > 0.05). The metal-porcelain bond strength value of the cast group was (33.11 +/- 4.98) MPa, and that of the SLM group was (30.94 +/- 5.98) MPa. The specimens in both test groups exhibited mixed failure.

CONCLUSION

The metal-porcelain system processed by SLM exhibit a bond strength that is similar to that of the cast group. This system also display a high precision.

[Comprehensive utilization and development of traditional Tibetan medicine in China]

OBJECTIVE

To deal with the further investigation field by discussing the status and present problem of traditional Tibetan medicine.

METHOD

Previous relevant investigations and literatures were summed up in the field. The present situation of traditional Tibetan medicine in China was analysed.

RESULT

The textual research, basic medicinal property, exploration of developable medicinal resource and protection of endangered medicinal species etc. were elaborated and the key problem of further investigation in 21st century was expounded.

CONCLUSION

The textual research, basic medicinal property, exploration of develoable medicinal resources, especially monographic study on protection of major endangered medicinal resources should be intensified. Domestication and cultivation, and exploration of good-quality medicinal resources, quality evaluation and exploitation of effectual prescriptions are the focal field in the study of traditional Tibetan medicine.

L-Altruronic acid formed by epimerization of D-galacturonic acid methyl esters during saponification of citrus pectin

While searching for oligosaccharides containing rhamnose residues in the endopolygalacturonase (EPG) digest of saponified citrus pectin, we found several oligomers containing, in addition to galacturonic acid, a sugar previously unreported in pectin. The 1- and 2-D 1H NMR spectra of the oligosaccharides were consistent with the sugar being a uronic acid with its 2- and 3-hydroxyls being axial and 4-hydroxyl being equatorial. MALDI-TOF mass spectrometry indicated that the oligomers consisted solely of uronic acids. Reduction of the uronic acids in the oligosaccharides converted them to galactose and altrose. The altrose was found to be the L enantiomer by comparison of its trimethylsilyl (-)-2-butyl glycosides to those of authentic D-altrose and a racemic mixture. The sugar was not found in oligosaccharides prepared from EPG digestion of citrus pectin deesterified with pectin methylesterase rather than saponification. Thus, it appears that during saponification, a small proportion of the methylesterified galacturonic acid residues in pectins is epimerized at C-5 leading to formation of L-altruronic acid residues.

Binding of the human papillomavirus type 16 E7 oncoprotein and the adeno-associated virus Rep78 major regulatory protein in vitro and in yeast and the potential for downstream effects

OBJECTIVE

Both human papillomavirus (HPV) and adeno-associated virus (AAV) are common anogenital viruses and likely co-infect the epithelium in vivo. However, whereas HPVs are positively associated with cervical cancer, AAV appears to be negatively associated. In tissue culture, AAV-encoded Rep78--which is essential for AAV--inhibits gene expression and oncogenic transformation by HPV-16/18 and bovine papillomavirus type 1. Here we observed whether the HPV-16 E7 oncoprotein might recognize and bind Rep78. Further, upon finding Rep78-E7 binding, we investigated some of the potential downstream effects such an interaction might have. E7 is capable of recognizing a variety of proteins, including RB105, TATA box-binding protein (TBP), TBP-associated factor (TAF)(II)110, E2F, cyclins A and D, and c-jun. Some of these interactions are likely responsible for E7's cancer-promoting activity.

STUDY DESIGN/METHODS

Rep78-E7 interaction was investigated in vitro by West(far)-Western and affinity chromatography analysis and in vivo in living yeast by the GAL4 two-hybrid cDNA assay. Mapping of the E7 binding domain within Rep78 was carried out using a series of amino- and carboxy-truncated Rep78 proteins in a West(far)-Western assay. Downstream effects of the interaction were analyzed by competitive affinity chromatography (protein-protein) and competitive electrophoretic mobility shift assay (protein-DNA).

RESULTS

E7 and Rep78 were found to interact both in vitro and in vivo (yeast) in all assays attempted. The E7 binding domain within Rep78 was found to reside within amino acids 121-370. Regarding downstream effects of this interaction, Rep78 was found to mildly inhibit E7-TAF(II)110 and E7-RB105 interaction in vitro but to have little affect on E7-TBP interaction. Finally, it was found that E7 was able to affect Rep78's interaction with AAV's terminal repeat (TR) DNA in vitro, reducing the formation of the largest sized Rep78-TR complexes in a dosage-dependent manner.

CONCLUSIONS

These data suggest that the Rep78-E7 interaction may have repercussions for both viruses. The Rep78-E7 interaction may be a second mechanism, in addition to Rep78 regulation of the p97 promoter, by which AAV inhibits HPV-16 oncogenic transformation. These data also suggest that HPV-16 may affect the AAV life cycle by altering Rep78-TR interaction.

Binding of the human papillomavirus type 16 p97 promoter by the adeno-associated virus Rep78 major regulatory protein correlates with inhibition

Human papillomavirus type 16 (HPV-16) infection is positively associated with cervical cancer, whereas adeno-associated virus (AAV) infection is negatively associated with this same cancer. In earlier studies these two virus types have been shown to directly interact, with AAV inhibiting or enhancing papillomavirus functions depending upon the specific circumstances. One defined interaction between these two viruses is the ability of the AAV Rep78 major regulatory protein to inhibit gene expression of the E6 promoter of BPV-1 (bovine papillomavirus type 1) and HPV types 16 and 18. As Rep78 is a DNA binding transcription factor, we considered whether Rep78 might bind HPV-16 DNA. Here, Rep78 is demonstrated to bind a 44-base pair region (nucleotides 14-56) within the HPV-16 p97 promoter using the electrophoretic mobility shift assay. This region is important for HPV-16 because it includes functional Sp1 and E2 protein binding motifs as well as part of the origin of replication. Furthermore, two Rep78 amino acid substitution mutants, at positions 77 or 64-65, were identified that did not recognize p97 DNA. Both of these Rep78 mutants were found to be defective for inhibition of p97 promoter activity in HeLa and T-47D nuclear extracts in vitro, in a transient chloramphenicol acetyltransferase assay, as well as defective for full inhibition of HPV-16-directed focus formation. These data, taken together, strongly suggest that the Rep78-p97 promoter interaction is at least partially responsible for Rep78-mediated inhibition of HPV-16. Finally, the finding that Rep78 specifically recognizes p97 DNA is surprising because the p97 promoter region contains no GAGC motifs, the core motif for Rep78 recognition. These data suggest that the p97 promoter may represent a new prototypical DNA target type for Rep78.

Induction of human papillomavirus-specific CD4(+) and CD8(+) lymphocytes by E7-pulsed autologous dendritic cells in patients with human papillomavirus type 16- and 18-positive cervical cancer

Human papillomavirus (HPV) type 16 (HPV 16) and HPV type 18 (HPV 18) are implicated in the induction and progression of the majority of cervical cancers. Since the E6 and E7 oncoproteins of these viruses are expressed in these lesions, such proteins might be potential tumor-specific targets for immunotherapy. In this report, we demonstrate that recombinant, full-length E7-pulsed autologous dendritic cells (DC) can elicit a specific CD8(+) cytotoxic T-lymphocyte (CTL) response against autologous tumor target cells in three patients with HPV 16- or HPV 18-positive cervical cancer. E7-specific CTL populations expressed strong cytolytic activity against autologous tumor cells, did not lyse autologous concanavalin A-treated lymphoblasts or autologous Epstein-Barr virus-transformed lymphoblastoid cell lines (LCL), and showed low levels of cytotoxicity against natural killer cell-sensitive K562 cells. Cytotoxicity against autologous tumor cells could be significantly blocked by anti-HLA class I (W6/32) and anti-CD11a/LFA-1 antibodies. Phenotypically, all CTL populations were CD3(+)/CD8(+), with variable levels of CD56 expression. CTL induced by E7-pulsed DC were also highly cytotoxic against an allogeneic HLA-A2(+) HPV 16-positive matched cell line (CaSki). In addition, we show that specific lymphoproliferative responses by autologous CD4(+) T cells can also be induced by E7-pulsed autologus DC. E7-specific CD4(+) T cells proliferated in response to E7-pulsed LCL but not unpulsed LCL, and this response could be blocked by anti-HLA class II antibody. Finally, with two-color flow cytometric analysis of intracellular cytokine expression at the single-cell level, a marked Th1-like bias (as determined by the frequency of gamma interferon- and interleukin 4-expressing cells) was observable for both CD8(+) and CD4(+) E7-specific lymphocyte populations. Taken together, these data demonstrate that full-length E7-pulsed DC can induce both E7-specific CD4(+) T-cell proliferative responses and strong CD8(+) CTL responses capable of lysing autologous naturally HPV-infected cancer cells in patients with cervical cancer. These results may have important implications for the treatment of cervical cancer patients with active or adoptive immunotherapy.

Use of scavenger beads to remove excess labeling reagents from capillary zone electrophoresis samples

In many cases, samples for capillary zone electrophoresis (CZE) are derivatized with a chromophore or fluorophore to enhance their detectability. To ensure efficient labeling, a large excess of labeling agent is often used, which leads to the presence of a large peak for unreacted reagent. Here we report that excess reagent can be reacted with "scavenger beads" carrying an appropriate functional group to remove it from the sample solution. We present examples of removal of aminonaphthalene mono-, di-, and trisulfonic acid from mixtures in which they were used to label mono- or oligosaccharides by reductive amination. Aldehyde-containing scavenger beads were made by oxidizing Sephadex G-50 beads with sodium periodate. These were added to the labeling reaction mixtures after the reductive amination of the sugars was complete. Almost complete elimination of the peak from the labeling agent could be achieved.

Scarcity or complete lack of single rhamnose residues interspersed within the homogalacturonan regions of citrus pectin

Commercial citrus pectin containing galacturonic acid and rhamnose in a ratio of approximately 40:1 was saponified and then exhaustively digested with endopolygalacturonase (EPG). The products were separated by ultrafiltration into low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions. The LMW fraction accounted for 80% of the starting material, but for only 10% of the total rhamnose. The molar ratio of galacturonic acid to rhamnose of the LMW fraction was 236, suggesting that very few small Rha-containing oligomers were generated by the EPG digestion. No distinct Rha-containing oligomers were found by various chromatographic analyses of the LMW fraction. The HMW fraction, which only accounted for 10% by weight of the starting pectin, contained more than 85% of the rhamnose. The ratio of GalA to Rha in the HMW fraction was 1.7:1 and partial acid hydrolysis of this fraction produced a series of oligomers consisting of GalA-Rha repeating units, suggesting that it contained rhamnogalacturonan, which has a backbone composed of GalA-Rha disaccharide repeating units. The HMW fraction also contained large amounts of arabinose and galactose, which probably originated from side chains linked to some of the rhamnose residues. We propose that commercial citrus pectin is composed of two regions: the predominant region consists of chains of uninterrupted 1,4-linked alpha-D-GalA residues with between 60-70% of the residues methyl esterified; and the other region consists of rhamnogalacturonan with a backbone composed of GalA-Rha disaccharide repeating units and neutral sugar side chains.

The adeno-associated virus Rep78 major regulatory protein binds the cellular TATA-binding protein in vitro and in vivo

Rep78 is the major regulatory protein of adenoassociated virus (AAV). Rep78 is able to transcriptionally regulate all three of AAV's promoters, as well as a variety of heterologous promoters. In an attempt to understand the mechanism of action by which Rep78 is able to regulate gene expression, we are investigating Rep78's possible protein-protein interaction with basal transcription factors. One such critical basal transcription factor is the human TATA binding protein, TBP. TBP is a core factor required for the assemblage of the transcription initiation complex, TFIID. In this report an in vitro interaction between Rep78 and TBP was demonstrated in three different assay systems, including West(far)-Western analysis, electrophoretic mobility shift assay-supershift, and coimmunoprecipitation. Furthermore, using the yeast GAL4 two-hybrid system, an in vivo interaction between Rep78 and TBP was also demonstrated. Further still, the amino half of Rep78 is shown to be needed for Rep78-TBP interaction. Mutations within this region of Rep78 are known to be defective for transcriptional regulatory ability, suggesting a biological role for this interaction. Thus, Rep78 may regulate transcription through binding and regulating TBP's numerous interactions. Furthermore, as Rep78 is known to bind at least one other transcription factor (Sp 1) and likely others, Rep78 may function as a TBP-associated factor in an altered TFIID-like complex.

Synthesis and 32P-postlabeling/high-performance liquid chromatography separation of diastereomeric 1,N2-(1,3-propano)-2'-deoxyguanosine 3'-phosphate adducts formed from 4-hydroxy-2-nonenal

4-Hydroxy-2-nonenal (HNE), a major electrophilic byproduct of lipid peroxidation, is mutagenic and cytotoxic. The two pairs of HNE-derived diastereomeric 1,N2-propanodeoxyguanosine 3'-monophosphate adducts were synthesized from reaction of HNE with 2'-deoxyguanosine 3'-monophosphate. After HPLC separation, these adducts were characterized by UV-visible absorption and negative ion electrospray ionization MS/MS analysis. To further characterize the structures, these adducts were dephosphorylated to the corresponding HNE-modified deoxyguanosine adducts and their HPLC retention times and UV spectra were compared with those of the synthetic standards prepared from reaction of HNE with 2'-deoxyguanosine. Separation of these adducts by 32P-postlabeling/HPLC was developed. Reaction of HNE with calf thymus DNA resulted in only one pair of diastereomeric adducts, with one adduct predominantly formed with a modification level of 1.2 +/- 0.5 adducts/10(7) nucleotides.