P. Gingivalis and E. Coli Lipopolysaccharides Exhibit Different Systemic but Similar Local Induction of Inflammatory Markers

Background Porphyromonas gingivalis is a gram-negative bacterium that is an important etiologic agent of human adult periodontitis. The goal of the study was to test the hypothesis that two different isoforms, PgLPS1435/1449 and PgLPS1690 exhibit differences in their capacity to stimulate systemic versus local responses compared to E. coli LPS. Methods Lipopolysaccharide (LPS) was inoculated into the scalp of mice and the response was measured locally at the site of site of inoculation and systemically in the heart/aorta. VCAM-1 was assessed at the protein level by ELISA and VCAM-1, E-selectin, and ICAM-1 at the RNA level of RNase protection assay. Serum TNF-α levels were also measured. Results E. coli LPS and both isoforms of P. gingivalis LPS groups were relatively potent in stimulating expression of inflammatory markers with E. coli LPS being somewhat more potent. In contrast, when the systemic response was measured in the heart/aorta, E. coli but not P. gingivalis LPS significantly induced inflammatory markers. At moderate to low doses (1 and 10 ug per injection) serum TNF–α levels were minimally induced by P. gingivalis LPS compared to E. coli LPS. Conclusion The results indicate that both forms of P. gingivalis LPS stimulate an inflammatory response when injected into connective tissue but are minimally stimulatory when a systemic response is measured. In contrast E. coli LPS is a potent stimulus at both the systemic and local level

Advanced Glycation End Products Stimulate Osteoblast Apoptosis Via the MAP Kinase and Cytosolic Apoptotic Pathways

We have previously shown that diabetes significantly enhances apoptosis of osteoblastic cells in vivo and that the enhanced apoptosis contributes to diabetes impaired new bone formation. A potential mechanism is enhanced apoptosis stimulated by advanced glycation end products (AGEs). To investigate this further, an advanced glycation product, carboxymethyl lysine modified collagen (CML-collagen), was injected in vivo and stimulated a 5-fold increase in calvarial periosteal cell apoptosis compared to unmodified collagen. It also induced apoptosis in primary cultures of human or neonatal rat osteoblastic cells or MC3T3-E1 cells in vitro. Moreover, the apoptotic effect was largely mediated through RAGE receptor. CML-collagen increased p38 and JNK activity 3.2- and 4.4-fold, respectively. Inhibition of p38 and JNK reduced CML-collagen stimulated apoptosis by 45% and 59% and by 90% when used together (P \u3c 0.05). The predominant apoptotic pathway induced by CML-collagen involved caspase-8 activation of caspase-3 and was independent of NF-κB activation. When osteoblastic cells were exposed to a long-term low dose incubation with CML-collagen, there was a higher degree of apoptosis compared to short-term incubation. In more differentiated osteoblastic cultures, apoptosis was enhanced even further. These results indicate that advanced glycation end products, which accumulate in diabetic and aged individuals, may promote apoptosis of osteoblastic cells and contribute to deficient bone formation

Performance enhancement of point-to-point diffuse links at 265 nm under fog conditions

It is known that the tempting features of free space Non-Line-Of-Sight (NLOS) communications systems operating in the Ultraviolet C-band between 200 and 280 nm are the significantly reduced solar irradiance on ground level, the intense scattering and its combination with strong absorption which ensures the covertness against distant eavesdroppers or jammers. In the majority of the experimental surveys that have been published so far, the performance of point-to-point links has been evaluated under clear atmosphere without taking into account the weather conditions. In this work, it is shown that harsh atmospheric conditions due to fog appearance can be advantageous to short distance NLOS transmissions at 265 nm. Initially, the impact of fog on the losses of the diffuse wireless channels was investigated theoretically. Afterwards, an experimental survey of both the losses and the performance of low rate amplitude signals' transmissions for two atmosphere cases followed. Initially, the satisfactory relation between scattering and absorption at 265 nm was verified by deploying outdoor NLOS point-to-point links under clear atmosphere. The transmitter consisted of 4 Light Emitting Diodes and the optical part of the receiver included a filter and a Photo-Multiplier tube. Then, the beneficial impact of artificially generated fog on scattering was exploited not only to enhance the system performance but also to identify the modification of the conditions. The experimental results showed a clear decrease of both the losses and the Bit Error Rate under fog conditions making such a system a perfect candidate for low rate communications under dense atmosphere