Porphyromonas gingivalis induce apoptosis in human gingival epithelial cells through a gingipain-dependent mechanism

<p>Abstract</p> <p>Background</p> <p>The oral pathogen <it>Porphyromonas gingivalis </it>has been shown to modulate apoptosis in different cell types, but its effect on epithelial cells remains unclear.</p> <p>Results</p> <p>We demonstrate that primary human gingival epithelial cells (HGECs) challenged with live <it>P. gingivalis </it>for 24 hours exhibit apoptosis, and we characterize this by M30 epitope detection, caspase-3 activity, DNA fragmentation and Annexin-V staining. Live bacteria strongly upregulated intrinsic and extrinsic apoptotic pathways. Pro-apoptotic molecules such as caspase-3, -8, -9, Bid and Bax were upregulated after 24 hours. The anti-apoptotic Bcl-2 was also upregulated, but this was not sufficient to ensure cell survival. The main <it>P. gingivalis </it>proteases arginine and lysine gingipains are necessary and sufficient to induce host cell apoptosis. Thus, live <it>P. gingivalis </it>can invoke gingival epithelial cell apoptosis in a time and dose dependent manner with significant apoptosis occurring between 12 and 24 hours of challenge via a gingipain-dependent mechanism.</p> <p>Conclusion</p> <p>The present study provides evidence that live, but not heat-killed, <it>P. gingivalis </it>can induce apoptosis after 24 hours of challenge in primary human gingival epithelial cells. Either arginine or lysine gingipains are necessary and sufficient factors in <it>P. gingivalis </it>elicited apoptosis.</p

Solar Neutron Events of October-November 2003

During the period when the Sun was intensely active on October-November 2003, two remarkable solar neutron events were observed by the ground-based neutron monitors. On October 28, 2003, in association with an X17.2 large flare, solar neutrons were detected with high statistical significance (6.4 sigma) by the neutron monitor at Tsumeb, Namibia. On November 4, 2003, in association with an X28 class flare, relativistic solar neutrons were observed by the neutron monitors at Haleakala in Hawaii and Mexico City, and by the solar neutron telescope at Mauna Kea in Hawaii simultaneously. Clear excesses were observed at the same time by these detectors, with the significance calculated as 7.5 sigma for Haleakala, and 5.2 sigma for Mexico City. The detector onboard the INTEGRAL satellite observed a high flux of hard X-rays and gamma-rays at the same time in these events. By using the time profiles of the gamma-ray lines, we can explain the time profile of the neutron monitor. It appears that neutrons were produced at the same time as the gamma-ray emission.Comment: 35 pages, 21 figures, accepted for publication in Ap

In vitro modeling of host-parasite interactions: the 'subgingival' biofilm challenge of primary human epithelial cells

BACKGROUND: Microbial biofilms are known to cause an increasing number of chronic inflammatory and infectious conditions. A classical example is chronic periodontal disease, a condition initiated by the subgingival dental plaque biofilm on gingival epithelial tissues. We describe here a new model that permits the examination of interactions between the bacterial biofilm and host cells in general. We use primary human gingival epithelial cells (HGEC) and an in vitro grown biofilm, comprising nine frequently studied and representative subgingival plaque bacteria. RESULTS: We describe the growth of a mature 'subgingival' in vitro biofilm, its composition during development, its ability to adapt to aerobic conditions and how we expose in vitro a HGEC monolayer to this biofilm.Challenging the host derived HGEC with the biofilm invoked apoptosis in the epithelial cells, triggered release of pro-inflammatory cytokines and in parallel induced rapid degradation of the cytokines by biofilm-generated enzymes. CONCLUSION: We developed an experimental in vitro model to study processes taking place in the gingival crevice during the initiation of inflammation. The new model takes into account that the microbial challenge derives from a biofilm community and not from planktonically cultured bacterial strains. It will facilitate easily the introduction of additional host cells such as neutrophils for future biofilm:host cell challenge studies. Our methodology may generate particular interest, as it should be widely applicable to other biofilm-related chronic inflammatory diseases

Never Deaf of Learning with Heart: Understanding the Essence of Handling Pupils with Hearing Impairment

This transcendental phenomenology study aimed at describing and understanding the lived experience of eight (8) Special education teachers handling learners with hearing impairment.Specifically, they were private school teachers in the cities of Biñan, Sta. Rosa and San Pedro Laguna, Philippines who were purposively selected using inclusion criteria. Framed with the approach of Moustakas (1994) as cited by Creswell (2007), the researchers carefully analyzed the participants’ verbatim accounts which resulted in six (6) themes categorized into textural and structural descriptions. Collectively taken, the essence of the study highlighted the participants’ experience in handling hearing-impaired learners which covered engaging them in different activities (Theme 1), customized communication with them (Theme 2), and love and drive to reach out to these individuals (Theme 3). They coped with the challenges they face by clinging to the vital role of assessment tools (Theme 4), highlighting values in teaching (Theme 5) and viewing their profession as a calling of commitment and devotion (Theme 6). The lived experiences of special education teachers with learners diagnosed with hearing impairment may serve as a feedback for special education instructional materials suppliers or developers in improving the contents of their works to better cater the needs of special education teachers in terms of the choice of innovated instructional materials that specifically address the learning needs of students in special education

Acceleration of Solar Wind Ions by Nearby Interplanetary Shocks: Comparison of Monte Carlo Simulations with Ulysses Observations

The most stringent test of theoretical models of the first-order Fermi mechanism at collisionless astrophysical shocks is a comparison of the theoretical predictions with observational data on particle populations. Such comparisons have yielded good agreement between observations at the quasi-parallel portion of the Earth's bow shock and three theoretical approaches, including Monte Carlo kinetic simulations. This paper extends such model testing to the realm of oblique interplanetary shocks: here observations of proton and alpha particle distributions made by the SWICS ion mass spectrometer on Ulysses at nearby interplanetary shocks are compared with test particle Monte Carlo simulation predictions of accelerated populations. The plasma parameters used in the simulation are obtained from measurements of solar wind particles and the magnetic field upstream of individual shocks. Good agreement between downstream spectral measurements and the simulation predictions are obtained for two shocks by allowing the the ratio of the mean-free scattering length to the ionic gyroradius, to vary in an optimization of the fit to the data. Generally small values of this ratio are obtained, corresponding to the case of strong scattering. The acceleration process appears to be roughly independent of the mass or charge of the species.Comment: 26 pages, 6 figures, AASTeX format, to appear in the Astrophysical Journal, February 20, 199

MiRNA-181a regulates Toll-like receptor agonist-induced inflammatory response in human fibroblasts

MicroRNAs (miRNA) regulate the synthesis of cytokines in response to Toll-like receptor (TLR) activation. Our recent microarray study comparing normal and inflamed human dental pulps showed that miRNA-181 (miR-181) family is differentially expressed in the presence of inflammation. Prior studies have reported that the dental pulp, which is composed primarily of TLR4/2+ fibroblasts, expresses elevated levels of cytokines including Interleukin-8 (IL-8) when inflamed. In this study, we employed an in-vitro model to determine the role of the miRNA 181 family in the TLR agonist-induced response in human fibroblasts. TLR4/2+ primary human dental pulp fibroblasts were stimulated with lipopolysaccharide from Porphyromonas gingivalis (Pg LPS), a known oral pathogen, and IL-8 and miR-181 expression measured. An inversely proportional relationship between IL-8 and miR-181a was observed. In-silico analysis identified a miR-181a binding site on the 3′UTR of IL-8 which was confirmed by dual-luciferase assays. MiR-181a directly binds to the 3′UTR of IL-8, an important inflammatory component of the immune response, and modulates its levels. This is the very first report demonstrating miR-181a regulation of IL-8

Levels of insulin and HOMA-IR in adolescents in Saltillo, Coahuila, Mexico

An alarming rise of obesity in adolescents has been observed, placing them at risk of developing resistance to insulin (IR) and its adverse metabolic consequences such as diabetes mellitus type 2 (DM2), metabolic syndrome and cardiovascular disease. Objective: To know the prevalence of obesity, and the levels of glucose, insulin and HOMA-IR and its association with the BMIz, waist circumference and the pubertal stage in a random sample of adolescents. Materials and methods: 292 adolescents between 12 and 15 years (152 female and 140 male), whose anthropometric measurements (weight, height and waist circumference) were taken, body mass index calculated and Z-score determined. Blood glucose and insulin levels were evaluated from a sample of blood and their HOMA-IR was determined. Results: The results showed that 32.5% were obese, 22.3% were overweight and 23.6% showed adolescent central obesity. Glucose levels (p = 0.016), insulin (p = 0.0001) and HOMA-IR (p = 0.0001) showed significant differences in the group with obesity. Values of the three parameters were increased with the stage of puberty. We found significant differences in the levels of glucose (p = 0.0388), insulin (p = 0.0005) and HOMA-IR (p = 0.0001) between the prepubertal and postpubertal stages

Improved Performance of an Epoxy Matrix as a Result of Combining Graphene Oxide and Reduced Graphene

We present an easy and effective way to improve the mechanical properties of an epoxy matrix by reinforcing it with a combination of graphene oxide (GO) and reduced graphene oxide (RGO). These nanocomposites were prepared with different load of nanofillers: 0.1, 0.4, 0.7, 1.0 wt% and a neat epoxy. Ratios of graphene oxide and reduced graphene (GO : RGO) employed were: 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0. Results show that with only 0.4 wt% and a ratio 0.2 : 0.75 of GO : RGO, tensile strength and tensile toughness are 52% and 152% higher than neat epoxy while modulus of elasticity was improved ~20%. The obtained results suggest that it is possible achieve advantageous properties by combining graphene in oxidized and reduced conditions as it shows a synergic effect by the presence of both nanofillers

The Dynamics of Taro (<em>Colocasia esculenta</em>) through Value Chain Analysis and Crop Accounting in Partido District, Camarines Sur, the Philippines

This paper scrutinizes and evaluates the value chain of taro in Partido district, Camarines Sur, the Philippines. Taro (Colocasia Esculenta) is rich in carbohydrates and also a good replacement for wheat flour. However, it is well-known to farmers for its ability to produce a reasonable yield in poor soil conditions with less or no farm inputs. It is this reason why Taro is often grown by resource-limited farmers and regarded as a good source of food security. To tap its full potential, this study was conducted to understand and analyze the flow of Taro. This study employed participatory techniques, crop accounting, and financial analysis. The Taro value chain has varied gender roles, according to this study. It also highlighted why, despite having a choice, farmers frequently chose the less profitable transaction path. It also solved the mystery of low productivity in this locale as compared with the national production. The results also showed the cost build-up of Taro and the profitability of each player in the chain. Farmers usually end up at a 22% profit-to-cost ratio by selling the harvest to the middleman, while sellers usually end up at a 47% profit-to-cost ratio. The existing entry barriers in each chain were also identified with the researchers’ recommendations on how to possibly eliminate or mitigate them. This extensive analysis can be valuable to stakeholders in the Taro value chain in the area, as well as government entity and non-governmental organizations in developing initiatives or projects on behalf of the players