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Cancer progression involves biomechanical changes within transformed cells and the surrounding extracellular matrix (ECM). The viscoelastic features of fluidity and elasticity that are based on a novel Kelvin–Voigt fractional derivative (KVFD) model were found capable of discriminating normal, benign and malignant breast biopsy tissues on the cellular scale. The improved specificity of KVFD model parameters derives from greater accuracy of fitting the entire approaching force-indentation measurement curve ( R 2 > 0.99) compared with traditional elastic models ( R 2 < 0.86). Moreover, model parameters can be interpreted in terms of histopathological features. First, statistical comparisons reveal there are significant differences (p < 0.001) in elasticity E0, fluidity α , and viscosity τ among healthy, benign, and malignant groups. Malignant breast tissues show low-value, broad-distributions in E0 and with high fluidity α as compared with healthy and benign tissues. Second, histograms of E0 and α provide distinctive features by fitting to Gaussian mixture (GM) models. The histograms of E0 and α are best fit by two kernels GM for malignant tissues, indicating that the cells are soft but with high fluidity and the ECM is stiff but with low fluidity. However, the data suggest one-kernel GM model for benign tissue and a patched uniform distribution for healthy tissue. Third, using fluidity α as the test statistic, the area under the receiver operator characteristic curve (AUC) is 0.701 ± 0.012 (p < 0.0001) for control versus malignant and 0.706 ± 0.013 (p < 0.0001) for benign versus malignant group. Variations in tissue fluidity and elasticity offer a concise set of viscoelastic biomarkers that correlate well with histopathological features. [ABSTRACT FROM AUTHOR]

Two-photon fluorescence correlation spectroscopy (2P-FCS) within single dendritic spines of living hippocampal pyramidal neurons was used to resolve various subpopulations of mobile F-actin during activity-dependent structural changes such as potentiation induced spine head growth. Two major classes of mobile F-actin were discovered: very dynamic and about a hundred times less dynamic F-actin. Spine head enlargement upon application of Tetraethylammonium (TEA), a protocol previously used for the chemical induction of long-term potentiation (cLTP) strictly correlated to changes in the dynamics and filament numbers in the different actin filament fractions. Our observations suggest that spine enlargement is governed by a mechanism in which longer filaments are first cut into smaller filaments that cooperate with the second, increasingly dynamic shorter actin filament population to quickly reorganize and expand the actin cytoskeleton within the spine head. This process would allow a fast and efficient spine head enlargement using a major fraction of the actin filament population that was already present before spine head growth. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ventilator-associated pneumonia (VAP) has been identified as the most common nosocomial infection in intensive care units (ICUs) with associated health and financial costs. To date, more research has been carried out in adult ICUs than in paediatric units, thus prompting a review and investigation of the implications for paediatric practice. AIMS: To identify relevant paediatric literature surrounding VAP and use this in association with research carried out in the adult environment to establish the implications of VAP and possible management strategies. SEARCH STRATEGIES: A literature search was undertaken using databases within DialogDatastar to identify the extent to which VAP has been researched in both paediatric and adult centres. This information was used to try and gain a clearer concept of the impact and management of VAP in the paediatric setting. Key words and combinations included VAP, intensive care, paediatric, antibiotics, positioning, suction, economics, management, nosocomial and morbidity and mortality. RESULTS OF ANALYSIS: Despite the documented significance of VAP in terms of its financial and health implications, discrepancies and inconsistencies exist surrounding the identification and treatment of VAP. This is reflected in paediatric centres by a dearth of literature on the subject and the lack of a national standard as to the management and prevention of VAP. Inappropriate management of VAP plays an important role in the development and spread of multiresistant bacteria within hospitals. CONCLUSIONS: While inadequate paediatric research exists, extrapolating from adult research suggests that the financial and health costs of VAP are substantial and can be reduced by introducing simple low-cost measures. Such measures include improving education surrounding VAP and its implications and making small changes in practice to improve and maintain oral hygiene standards. IMPLICATIONS: With a growing cohort of paediatric patients requiring short- and long-term ventilation, progress must be made in identifying the extent and impact of VAP in paediatric ICUs and among the community ventilated patients. This will require changes in practice and attitudes towards VAP for which an appropriate knowledge base would need to be established using audit and research. These issues are particularly relevant in the current environment given the links with multiresistant strains of bacteria within hospitals and the community. [ABSTRACT FROM AUTHOR]