System for application of controlled forces on dental implants in rat maxillae: Influence of the number of load cycles on bone healing.

Experimental studies on the effect of micromotion on bone healing around implants are frequently conducted in long bones. In order to more closely reflect the anatomical and clinical environments around dental implants, and eventually be able to experimentally address load-management issues, we have developed a system that allows initial stabilization, protection from external forces, and controlled axial loading of implants. Screw-shaped implants were placed on the edentulous ridge in rat maxillae. Three loading regimens were applied to validate the system; case A no loading (unloaded implant) for 14 days, case B no loading in the first 7 days followed by 7 days of a single, daily loading session (60 cycles of an axial force of 1.5 N/cycle), and case C no loading in the first 7 days followed by 7 days of two such daily loading sessions. Finite element modeling of the peri-implant compressive and tensile strains plus histological and immunohistochemical analyses revealed that in case B any tissue damage resulting from the applied force (and related interfacial strains) did not per se disturb bone healing, however, in case C, the accumulation of damage resulting from the doubling of loading sessions severely disrupted the process. These proof-of-principle results validate the applicability of our system for controlled loading, and provide new evidence on the importance of the number of load cycles applied on healing of maxillary bone.

Bicistronic transfer of CDKN2A and p53 culminates in collaborative killing of human lung cancer cells in vitro and in vivo.

Cancer therapies that target a single protein or pathway may be limited by their specificity, thus missing key players that control cellular proliferation and contributing to the failure of the treatment. We propose that approaches to cancer therapy that hit multiple targets would limit the chances of escape. To this end, we have developed a bicistronic adenoviral vector encoding both the CDKN2A and p53 tumor suppressor genes. The bicistronic vector, AdCDKN2A-I-p53, supports the translation of both gene products from a single transcript, assuring that all transduced cells will express both proteins. We show that combined, but not single, gene transfer results in markedly reduced proliferation and increased cell death correlated with reduced levels of phosphorylated pRB, induction of CDKN1A and caspase 3 activity, yet avoiding the induction of senescence. Using isogenic cell lines, we show that these effects were not impeded by the presence of mutant p53. In a mouse model of in situ gene therapy, a single intratumoral treatment with the bicistronic vector conferred markedly inhibited tumor progression while the treatment with either CDKN2A or p53 alone only partially controlled tumor growth. Histologic analysis revealed widespread transduction, yet reduced proliferation and increased cell death was associated only with the simultaneous transfer of CDKN2A and p53. We propose that restoration of two of the most frequently altered genes in human cancer, mediated by AdCDKN2A-I-p53, is beneficial since multiple targets are reached, thus increasing the efficacy of the treatment.

Granuloma Coinfection with Mycobacterium bovis, Mycobacterium avium subsp. paratuberculosis, and Corynebacterium pseudotuberculosis in Five Hunted Red deer (Cervus elaphus) in Portugal.

We report granulomatous lymphadenitis in red deer (Cervus elaphus) in Portugal caused by coinfection with Corynebacterium pseudotuberculosis, Mycobacterium bovis, and Mycobacterium avium subsp. paratuberculosis, as demonstrated by molecular methods.

Disseminated Mycobacterium bovis infection in red foxes (Vulpes vulpes) with cerebral involvement found in Portugal.

A total of 49 road-killed red foxes were used for the detection of Mycobacterium tuberculosis complex (MTC) in Portugal. MTC infection was detected by PCR in 10 red foxes (20.4%; 95% confidence interval [CI] 8.8-31.2%) and confirmed in three (6.1%; 95% CI 0.0-7.9%) of them by microbiological culture. The complex was detected in 20 tissues out of 441 by PCR techniques (4.5%; 95% CI 16.3-23.7%) and in seven tissues out of 441 (1.6%; 95% CI 4.6-9.4%) by culture. MTC was most frequently detected in the brain (8.2%) and in the mediastinal lymph nodes (8.2%). The seven cultures obtained were positive for M. bovis by PCR-based genotyping of the MTC targeting genomic deletions. This study confirms the presence of disseminated M. bovis in red foxes in Portugal, and it is the first report in the world of the natural infection in the animals' brains.

Leaves of Lolium multiflorum 'Lema' and tropical tree species as biomonitors of polycyclic aromatic hydrocarbons.

This study extends the current knowledge regarding the use of plants for the passive accumulation of anthropogenic PAHs that are present in the atmospheric total suspended particles (TSP) in the tropics and sub-tropics. It is of major relevance because the anthropic emissions of TSP containing PAHs are significant in these regions, but their monitoring is still scarce. We compared the biomonitor efficiency of Lolium multiflorum 'Lema' and tropical tree species (Tibouchina pulchra and Psidium guajava 'Paluma') that were growing in an intensely TSP-polluted site in Cubatão (SE Brazil), and established the species with the highest potential for alternative monitoring of PAHs. PAHs present in the TSP indicated that the region is impacted by various emission sources. L. multiflorum showed a greater efficiency for the accumulation of PAH compounds on their leaves than the tropical trees. The linear regression between the logBCF and logKoa revealed that L. multiflorum is an efficient biomonitor of the profile of light and heavy PAHs present in the particulate phase of the atmosphere during dry weather and mild temperatures. The grass should be used only for indicating the PAHs with higher molecular weight in warmer and wetter periods.

The redox state of Ipomoea nil 'Scarlet O'Hara' growing under ozone in a subtropical area.

The occurrence of visible leaf injury caused by ozone in Ipomoea nil 'Scarlet O'Hara' may be regulated by their redox state, affecting its bioindicator efficiency. Thus, this study aimed to determine whether the redox state of I. nil plants in a subtropical area (São Paulo, SE-Brazil) contaminated by ozone oscillates, and to identify the environmental factors behind these variations. We comparatively evaluated indicators of redox state (ascorbic acid, glutathione, superoxide dismutase, ascorbate peroxidase, glutathione reductase) and leaf injury during nine field experiments of 28 days each. The variations in the redox indicators were explained by the combined effects of chronic levels of ozone and meteorological variables (mainly global solar radiation and air temperature) 3-6 days prior to the sampling days. The ascorbic acid and glutathione were crucial for increasing plant tolerance to ozone. Weak visible injury was observed in all experiments and occurred in leaves with low levels of ascorbic and dehydroascorbic acids.

How the redox state of tobacco 'Bel-W3' is modified in response to ozone and other environmental factors in a sub-tropical area?

This study intended to determine whether the redox state in plants of Nicotiana tabacum 'Bel-W3' fluctuates in response to the environmental factors in a sub-tropical area contaminated by ozone (São Paulo, SE-Brazil) and which environmental factors are related to this fluctuation, discussing their biomonitoring efficiency. We comparatively evaluated the indicators of redox state (ascorbic acid, glutathione, superoxide dismutase, ascorbate peroxidase, and glutathione reductase) and leaf injury in 17 field experiments performed in 2008. The redox state was explained by the combined effects of chronic levels of O(3) and meteorological variables 4-6 days prior to the plant sampling. Moderate leaf injury was observed in most cases. The redox state of tobacco decreases few days after their placement in the sub-tropical environment, causing them to become susceptible to oxidative stress imposed by chronic doses of O(3). Its bioindicator efficiency would not be diminished in such levels of atmospheric contamination.