Katherine Howard

Screening and detection of human papillomavirus (HPV) high-risk strains HPV16 and HPV18 in saliva samples from subjects under 18 years old in Nevada: a pilot study

BackgroundHuman papillomaviruses (HPV) are oncogenic and mainly associated with cervical cancers. Recent evidence has demonstrated HPV infection in other tissues, including oral epithelia and mucosa. Although a recent pilot study provided new information about oral HPV status in healthy adults from Nevada, no information was obtained about oral HPV prevalence among children or teenagers, therefore, the goal of this study is to provide more detailed information about oral prevalence of high-risk HPV among children and teenagers in Nevada.MethodsThis retrospective study utilized previously collected saliva samples, obtained from pediatric dental clinic patients (aged 2 – 11) and local school district teenagers (aged 12-17) for high-risk HPV screening (n=118) using qPCR for quantification and confirmation of analytical sensitivity and specificity.ResultsA small subset of saliva samples were found to harbor high-risk HPV16 (n=2) and HPV18 (n=1), representing a 2.5% of the total. All three were obtained from teenage males, and two of these three samples were from White participants.ConclusionsAlthough this retrospective study could not provide correlations with behavioral or socioeconomic data, this project successfully screened more than one hundred saliva samples for high-risk HPV, confirming both HPV16 and HPV18 strains were present in a small subset. With increasing evidence of oral HPV infection in children, this study provides critical information of significant value to other dental, medical, oral and public health professionals who seek to further an understanding of oral health and disease risk in pediatric populations.

Lipopolysaccharide and platelet-activating factor stimulate expression of platelet-activating factor acetylhydrolase via distinct signaling pathways

ObjectivesThis study was designed to investigate and characterize the ability of platelet-activating factor (PAF) to induce the expression of platelet-activating factor acetylhydrolase (PAF-AH).MethodsRibonuclease protection assays and quantitative real-time PCR were used to investigate the ability of lipopolysaccharide (LPS) and PAF to regulate PAF-AH mRNA expression in human monocyte–macrophage 6 (MM6) cells. Pharmacological inhibitors of mitogen activated protein kinases (MAPK) and PAF receptor antagonists were used to investigate the mechanism of regulation of PAF-AH.ResultsPAF-AH mRNA levels were increased upon exposure to LPS or PAF in a dose-dependent manner. LPS elicited a more potent and rapid increase in PAF-AH expression than the PAF-stimulated response. However, when administered concomitantly, PAF augmented the LPS-stimulated response. LPS-stimulated PAF-AH expression was susceptible to partial inhibition by a p38 MAPK inhibitor and PAF receptor antagonists. PAF-induced up-regulation of PAF-AH levels was solely mediated via the PAF receptor and was p38 MAPK-independent.ConclusionThe proinflammatory mediators, LPS and PAF, increased levels of PAF-AH mRNA via distinct signaling pathways.

A molecular survey of S. mutans and P. gingivalis oral microbial burden in human saliva using Relative Endpoint Polymerase Chain Reaction (RE-PCR) within the population of a Nevada dental school revealed disparities among minorities

BackgroundThe University of Nevada, Las Vegas School of Dental Medicine recently opened an orthodontic treatment clinic to address the needs of the racially and ethnically diverse population of Southern Nevada, primarily focusing on the treatment and care of low-income and minority patients. Although orthodontic treatment and therapy has been shown to induce changes in the oral cavity, much of this evidence was collected from traditional White, teenage orthodontic clinic populations. The primary goal of this study was to describe the microbial burden of the cariogenic and periodontal pathogens, Streptococcus mutans and Porphyromonas gingivalis within the UNLV-SDM patient population.MethodsRepresentative saliva samples were collected from healthy adult patients for DNA isolation. Relative endpoint polymerase chain reaction (RE-PCR) was performed to ascertain the presence and relative microbial burden of these oral pathogens.ResultsNearly one quarter (13/56) or 23.3% of these patients had elevated levels of S. mutans, while (10/56) and 17.8% of these samples were found to have elevated levels of P. gingivalis, - with (90%) of P. gingivalis-positive samples from minority patients (X2 = 17.921, d.f. = 1; p < 0.0001).ConclusionsThese findings of elevated P. gingivalis levels, primarily among minority patients, may suggest underlying oral health practices contributing to adverse oral health conditions within this population. Oral health knowledge and practices among minority patients may be strongly influenced by other factors, including education and socioeconomic status, suggesting additional research may be needed to accurately determine the most appropriate standards for care and oral health education within this patient population.

Research enrichment: evaluation of structured research in the curriculum for dental medicine students as part of the vertical and horizontal integration of biomedical training and discovery

BackgroundResearch programs within medical and dental schools are important vehicles for biomedical and clinical discovery, serving as effective teaching and learning tools by providing situations in which predoctoral students develop problem-solving and critical-thinking skills. Although research programs at many medical and dental schools are well-established, they may not be well integrated into the predoctoral curriculum to effectively support the learning objectives for their students.MethodsA series of structured seminars, incorporating faculty research, was designed for first-year dental students at the University of Nevada, Las Vegas, School of Dental Medicine to reinforce and support the concepts and skills taught in concurrent courses. A structured research enrichment period was also created to facilitate student engagement in active research using faculty and student curricular release time. Course evaluations and surveys were administered to gauge student perceptions of the curricular integration of research, the impact of these seminars on recruitment to the research program, and overall levels of student satisfaction with research enrichment.ResultsThe analysis of course surveys revealed that students perceived the research-containing seminars effectively illustrated concepts, were logically sequenced, and were well-integrated into their curriculum. In addition, analysis of surveys revealed that the Integration Seminar courses motivated students to engage in research enrichment. Finally, this analysis provided evidence that students were very satisfied with their overall learning experience during research enrichment.ConclusionCurricular integration is one method of improving the teaching and learning of complicated and inter-related concepts, providing an opportunity to incorporate research training and objectives into traditionally separate didactic courses. Despite the benefits of curricular integration, finding the most appropriate points of integration, obtaining release time for curricular development and for research engagement, and funding predoctoral student research remain issues to be addressed in ways that reflect the character of the faculty and the goals of each institution.

Macrophage Colony Stimulating Factor-Induced Macrophage Differentiation Influences Myotube Elongation

Background: Unaccustomed exercise, high-intensity dynamic sports activities, or the resumption of normal weight-bearing after a period of disuse can induce skeletal muscle injury, which activates an inflammatory response followed by muscle regeneration. Specific subsets of macrophages are involved in muscle regeneration. But the exact role of macrophage differentiation during muscle regeneration remains to be elucidated. Objective: The objective of the study was to examine the effect of macrophage colony stimulating factor (M-CSF)-differentiated, lipopolysaccharides (LPS)-stimulated-macrophage-conditioned medium on muscle-cell proliferation, fusion, and elongation, which are key events during muscle regeneration and myogenesis. Method: Murine C2C12 myoblasts were cultured in conditioned medium obtained from PU5-1R macrophages that were (a) undifferentiated, unstimulated; (b) M-CSF-differentiated, unstimulated; (c) undifferentiated, LPS-stimulated; or (d) M-CSF-differentiated, LPS-stimulated. Myoblast proliferation ratio, nuclei number, and length were measured. Results: C2C12 cells cultured in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages had significantly more nuclei and greater length than cells cultured in conditioned medium from undifferentiated, LPS-stimulated macrophages. Dilution and denaturization of the M-CSF-differentiated, LPS-stimulated-macrophage medium prevented a marked increase in C2C12 nuclei number and length. However, the C2C12 myoblast proliferation ratio was significantly greater in conditioned medium from undifferentiated, LPS-stimulated macrophages than in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages. Conclusions: M-CSF-differentiated, LPS-stimulated macrophages may influence myogenesis and the early and terminal stages of muscle regeneration. This knowledge may aid in developing therapies that will directly expedite muscle repair and lead to faster rehabilitation and reduced rehabilitation costs.