Change in stiffness and effect of orientation in degrading polylactide films

The degradation pattern of the synthetic absorbable polyester is thought to occur from the center of the material outward, and the bulk degradation is therefore attributed largely to the chemical composition of the material. It was hypothesized that this pattern might be altered by changing the morphology of the material, i.e., by introducing molecular orientation into the system. A new solid state uniaxial orientation (SS-UO) process was used to orient two types of lactide polymer films. The films were exposed to a phosphate buffered solution, then chemically, mechanically, and visually analyzed after predetermined times. This paper explores the results of flexural testing which will be later correlated with microscopic degradation events, as part of the larger degradation study. The results show that, while orientation does not have an overall significant effect on the flexural modulus, there is a significant material/orientation interaction.     

Genomic amplification of a decoy receptor for Fas ligand in lung and colon cancer

Fas ligand (FasL) is produced by activated T cells and natural killer cells and it induces apoptosis (programmed cell death) in target cells through the death receptor Fas/Apol/CD95. One important role of FasL and Fas is to mediate immune-cytotoxic killing of cells that are potentially harmful to the organism, such as virus-infected or tumour cells. Here we report the discovery of a soluble decoy receptor, termed decoy receptor 3 (DcR3), that binds to FasL and inhibits FasL-induced apoptosis. The DcR3 gene was amplified in about half of 35 primary lung and colon tumours studied, and DcR3 messenger RNA was expressed in malignant tissue. Thus, certain tumours may escape FasL-dependent immune-cytotoxic attack by expressing a decoy receptor that blocks FasL.     

Differential recruitment of leukocyte populations and alteration of airway hyperreactivity by C-C family chemokines in allergic airway inflammation

Allergic airway inflammation is characterized by peribronchial leukocyte accumulation within the airway. Subsequent tissue damage leading to airway hyperreactivity is a result of activation of multiple leukocyte populations. Using an established model of allergic airway inflammation induced by intratracheal challenge with parasite (Schistosoma mansoni) egg Ag in presensitized mice, we have examined differential leukocyte recruitment. These studies have identified key chemokines involved in the accumulation of specific subsets of cells and the induction of airway hyperreactivity. In this study we have examined three C-C family chemokines, MCP-1, MIP-1alpha, and RANTES, which promote mononuclear cell- and eosinophil-specific recruitment to the airway. The in vivo neutralization of either MIP-1alpha or RANTES, but not MCP-1, significantly reduced the intensity of the eosinophil recruitment to the lung and airway during the allergic airway response by >50 and >60%, respectively. In contrast, neutralization of MCP-1 significantly reduced total leukocyte migration (>50% reduction), whereas neutralization of RANTES and MIP-1alpha had no significant affect on the overall leukocyte migration. Further examination of the effect of MCP-1 depletion indicated that both CD4+ and CD8+ lymphocyte subsets were decreased. Depletion of MCP-1 significantly reduced the airway hyperreactivity to near control levels, whereas depletion of MIP-1alpha or RANTES did not affect the intensity of airway hyperreactivity. These data indicate that multiple C-C chemokines are involved in the recruitment of particular leukocyte populations and that neutralization of MCP-1, but not RANTES or MIP-1alpha, significantly reduced airway hyperreactivity.     

A methodological basis for description and analysis of systems with complex switch-like interactions

A wide range of complex systems appear to have switch-like interactions, i.e. below (or above) a certain threshold x has no or little influence on y, while above (or below) this threshold the effect of x on y saturates rapidly to a constant level. Switching functions are frequently described by sigmoid functions or combinations of these. Within the context of ordinary differential equations we present a very general methodological basis for designing and analysing models involving complicated switching functions together with any other non-linearities. A procedure to determine position and stability properties of all stationary points lying close to a threshold for one or several variables, so-called singular stationary points, is developed. Such points may represent homeostatic states in models, and are therefore of considerable interest. The analysis provides a profound insight into the generic effects of steep sigmoid interactions on the dynamics around homeostatic points. It leads to qualitative as well as quantitative predictions without using advanced mathematical methods. Thus, it may have an important heuristic function in connection with numerical simulations aimed at unfolding the predictive potential of realistic models.     

Application of probability techniques to the objective interpretation of veterinary clinical biochemistry data

Methods for the interpretation of veterinary clinical biochemistry have not developed as rapidly as biochemical technology. However, the results of clinical biochemistry tests are only of value when they are interpreted appropriately. A retrospective study was undertaken to investigate the equine biochemistry data which had been stored in a veterinary hospital database. By applying percentile analysis and Bayesian probability methods to the clinical biochemistry and corresponding diagnosis data, a novel method for the interpretation of clinical biochemistry data has been developed. The method allows clinicians to determine whether a biochemistry value is abnormal, its degree of abnormality, and the most likely associated diagnoses. The method could be used to investigate a practice-based population and may have significant implications for the interpretation of clinical biochemistry data in veterinary medicine in the future.     

Death associated with disseminated intravascular coagulation after hip replacement

Sudden-onset disseminated intravascular coagulation (DIC) occurred 3 h after uneventful polymethacrylate bone cement insertion for a revision left Charnley hip replacement. Profuse bleeding caused a hypovolaemic state aggravating existing myocardial ischaemia; as a result death occurred secondary to myocardial infarction 6 h after operation.