Thermal alterations in patients with inflammatory diseases: a comparison between psoriatic and rheumatoid arthritis.

Functional infrared imaging (fIRI) is used to provide information on circulation, thermal properties and thermoregulatory function of the cutaneous tissue in several clinical settings. This study aims to evaluate the application of fIRI in rheumatoid arthritis (RA) assessment, evaluating the thermoregulatory alterations due to joint inflammation in RA patients both in basal conditions and after a mild functional (isometric) exercise, using the same protocol we projected in our recent work on psoriatic arthritis (PsA); fIRI outcomes were compared with those provided by power-Doppler ultrasonography. Ten patients with RA and 11 healthy controls were enrolled in the study. The cutaneous temperature dynamics of 20 regions of interest located on the dominant hand were recorded by means of high-resolution thermal imaging at baseline and after a functional exercise. RA patients showed lower thermal parameters compared to healthy controls, suggesting that the RA-related inflammatory state alters the normal thermal properties of the skin overlying inflamed joints. These results are different from PsA data observed in the previous study. fIRI applied to the study of the response to a functional stimulus may represent an innovative, non-invasive, and operator-independent method for the assessment of early RA.

Numerical analysis of the effects of material parameters on the lubrication mechanism for knee prosthesis.

The tibial component of current knee prostheses made of ultra high molecular weight polyethylene (UHMWPE) has a high degree of wear that causes knee inflammation, prosthesis loosening and subsequent replacement in not more than 15 years. In order to know which UHMWPE material properties have more influence on wear, a steady state lubrication model with non-Newtonian synovial fluid has been studied through numerical solution. The results show that UHMWPE has a very high elastic modulus that makes difficult a well lubricated artificial joint and induces the formation of very thin lubricating films between the moving surfaces with the same magnitude of roughness components. This study shows that the use of deformable porous materials in the tibial component could cause the lubricating film thickness to be higher than the average roughness and the pressure levels to be lower than the one predicted for UHMWPE. These two facts imply friction and wear reduction.

Elastohydrodynamic Lubrication of Porous Substrates. Application to Synovial Joint Analysis.

This work presents computational results for an elastohydrodynamic model with a porous wall. The model - inspired by the cartilage exudation phenomenon arising in living joints - allows the lubricating fluid to be transferred from the porous walls to the flow channel and viceversa. The system is represented through a strongly coupled set of nonlinear equations which involves hydrodynamic lubrication, plane elasticity and continuity in porous media. The solution technique employed is based on the finite element method, Newton iteration and parametric continuation processes. The predictions obtained uncover mechanisms that might be responsible for the extremely low friction coefficients found in synovial joints.

Multistage carcinogenesis utilizing human genital cells and human papillomaviruses.

The preponderance of evidence indicates that a subset of human papillomaviruses are important etiological agents for cervical cancer. However, the necessity of other agents as well as cellular events is recognized because not all women with papillomaviruses develop cancer. Therefore, the exact role of papillomaviruses in the multistage carcinogenesis process is unclear. Regulation of specific viral genes is important to the malignant process. The current study demonstrates that human herpesvirus-6, another ubiquitous virus, can infect genital epithelial cells and upregulate the expression of relevant papillomavirus genes. Thus, it can be considered a cofactor for cancer.

Transformation of Bloom's syndrome fibroblasts by DNA transfection.

Nonmalignant diploid human fibroblast cells (GM3498B) derived from a skin biopsy of a patient with Bloom's syndrome have been transformed by transfection with DNA from a tumorigenic mouse cell line (Ha-8) carrying a single copy of the Harvey murine sarcoma virus (Ha-MuSV) genome. The transformed cell lines have an extended life-span, form colonies in agarose, and proliferate in nude mice--characteristics of neoplastic transformation. Like the parental cells, they also exhibit a high spontaneous level of sister chromatid exchanges. Finally, the transformed cells contain most, if not all, of the Ha-MuSV genome as well as the human rasH sequence. These experiments show that these diploid nonmalignant human cells can be used as recipients in transfection experiments for studying the genetic control of neoplastic transformation.

Increased integration of viral genome following chemical and viral treatment of hamster embryo cells.

Treatment of hamster embryo cells with diverse classes of chemical carcinogens enhances transformation by a carcinogenic simian adenovirus, SA7. Virus transformed foci selected from plates pretreated with 3-methyl-cholanthrene (MCA), methyl methanesulfonate (MMS) or 7,12-dimethylbenz[a]anthracene (DMBA) and established as cell lines in culture, contained equivalent amounts of SA7 viral genome. However, hamster embryo cultures treated with MMS or nickel sulfate had increased amounts of SA7 DNA integrated into cellular DNA when examined 2--9 days after chemical treatment and viral inoculation. An increased uptake of SA7 DNA was demonstrated in hamster cells treated with MMS during DNA repair synthesis in cells retricted in scheduled DNA synthesis by amino acid deprivation; addition of virus after the repair period did not result in an increased integration of viral DNA. These data suggest that enhancement of viral oncogenesis by chemical carcinogens or mutagens may be related to the formation of additional attachment sites in cellular DNA for insertion of viral DNA, thereby increasing the probability of viral transformation.