The SerpinB1 knockout mouse a model for studying neutrophil protease regulation in homeostasis and inflammation

SerpinB1 is a clade B serpin, or ov-serpin, found at high levels in the cytoplasm of neutrophils. SerpinB1 inhibits neutrophil serine proteases, which are important in killing microbes. When released from granules, these potent enzymes also destroy host proteins and contribute to morbidity and mortality in inflammatory diseases including emphysema, chronic obstructive pulmonary disease, cystic fibrosis, arthritis, and sepsis. Studies of serpinB1-deficient mice have established a crucial role for this serpin in Pseudomonas aeruginosa infection by preserving lung antimicrobial proteins from proteolysis and by protecting lung-recruited neutrophils from a premature death. SerpinB1⁻/⁻ mice also have a severe defect in the bone marrow reserve of mature neutrophils demonstrating a key role for serpinB1 in cellular homeostasis. Here, key methods used to generate and characterize serpinB1⁻/⁻ mice are described including intranasal inoculation, myeloperoxidase activity, flow cytometry analysis of bone marrow myeloid cells, and elastase activity. SerpinB1-knockout mice provide a model to dissect the pathogenesis of inflammatory disease characterized by protease:antiprotease imbalance and may be used to assess the efficacy of therapeutic compounds.

Can wild ungulate carcasses provide enough biomass to maintain avian scavenger populations? An empirical assessment using a bio-inspired computational model

Background The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of several sanitary regulations has limited the availability of feeding resources provided by domestic carcasses, but theoretical studies assessing whether the availability of food resources provided by wild ungulates are enough to cover energetic requirements are lacking. Methodology/Findings We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics. We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available. Simulation testing of the model suggests that wild ungulates constitute an important food resource in the Pyrenees and the vulture population inhabiting this area could grow if only the food provided by wild ungulates would be available. On the contrary, in the Pre-Pyrenees there is insufficient food to cover the energy requirements of avian scavenger guilds, declining sharply if biomass from domestic animals would not be available. Conclusions/Significance Our results suggest that public health legislation can modify scavenger population trends if a large number of domestic ungulate carcasses disappear from the mountains. In this case, food provided by wild ungulates could be not enough and supplementary feeding could be necessary if other alternative food resources are not available (i.e. the reintroduction of wild ungulates), preferably in European Mediterranean scenarios sharing similar and socio-economic conditions where there are low densities of wild ungulates. Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

Genome sequence of Enterococcus hirae (Streptococcus faecalis) ATCC 9790, a model organism for the study of ion transport, bioenergetics, and copper homeostasis

Enterococcus hirae ATCC 9790 is a Gram-positive lactic acid bacterium that has been used in basic research for over 4 decades. Here we report the sequence and annotation of the 2.8-Mb genome of E. hirae and its endemic 29-kb plasmid pTG9790.

Assessment Of Dynamic Properties Of A Crowd Model For Human-Structure Interaction Modeling

As lightweight and slender structural elements are more frequently used in the design, large scale structures become more flexible and susceptible to excessive vibrations. To ensure the functionality of the structure, dynamic properties of the occupied structure need to be estimated during the design phase. Traditional analysis method models occupants simply as an additional mass; however, research has shown that human occupants could be better modeled as an additional degree-of- freedom. In the United Kingdom, active and passive crowd models are proposed by the Joint Working Group as a result of a series of analytical and experimental research. It is expected that the crowd models would yield a more accurate estimation to the dynamic response of the occupied structure. However, experimental testing recently conducted through a graduate student project at Bucknell University indicated that the proposed passive crowd model might be inaccurate in representing the impact on the structure from the occupants. The objective of this study is to provide an assessment of the validity of the crowd models proposed by JWG through comparing the dynamic properties obtained from experimental testing data and analytical modeling results. The experimental data used in this study was collected by Firman in 2010. The analytical results were obtained by performing a time-history analysis on a finite element model of the occupied structure. The crowd models were created based on the recommendations from the JWG combined with the physical properties of the occupants during the experimental study. During this study, SAP2000 was used to create the finite element models and to implement the analysis; Matlab and ME¿scope were used to obtain the dynamic properties of the structure through processing the time-history analysis results from SAP2000. The result of this study indicates that the active crowd model could quite accurately represent the impact on the structure from occupants standing with bent knees while the passive crowd model could not properly simulate the dynamic response of the structure when occupants were standing straight or sitting on the structure. Future work related to this study involves improving the passive crowd model and evaluating the crowd models with full-scale structure models and operating data.

Zebrafish (Danio rerio) as a model organism for investigating endocrine disruption

Endocrine-disrupting compounds (EDCs) are widespread in the aquatic environment and can cause alterations in development, physiological homeostasis and health of vertebrates. Zebrafish, Danio rerio, has been suggested as a model species to identify targets as well as modes of EDC action. In fact, zebrafish has been found useful in EDC screening, in EDC effects assessment and in studying targets and mechanisms of EDC action. Since many of the environmental EDCs interfere with the sex steroid system of vertebrates, most EDC studies with zebrafish addressed disruption of sexual differentiation and reproduction. However, other targets of EDCs action must not be overlooked. For using a species as a toxicological model, a good knowledge of the biological traits of this species is a pre-requisite for the rational design of test protocols and endpoints as well as for the interpretation and extrapolation of the toxicological findings. Due to the genomic resources available for zebrafish and the long experience with zebrafish in toxicity testing, it is easily possible to establish molecular endpoints for EDC effects assessment. Additionally, the zebrafish model offers a number of technical advantages including ease and cost of maintenance, rapid development, high fecundity, optical transparency of embryos supporting phenotypic screening, existence of many mutant strains, or amenability for both forward and reverse genetics. To date, the zebrafish has been mainly used to identify molecular targets of EDC action and to determine effect thresholds, while the potential of this model species to study immediate and delayed physiological consequences of molecular interactions has been instrumentalized only partly. One factor that may limit the exploitation of this potential is the still rather fragmentary knowledge of basic biological and endocrine traits of zebrafish. Information on species-specific features in endocrine processes and biological properties, however, need to be considered in establishing EDC test protocols using zebrafish, in extrapolating findings from zebrafish to other vertebrate species, and in understanding how EDC-induced gene expression changes translate into disease.

A papain-induced disc degeneration model for the assessment of thermo-reversible hydrogel-cells therapeutic approach

Nucleus pulposus (NP) regeneration by the application of injectable cell-embedded hydrogels is an appealing approach for tissue engineering. We investigated a thermo-reversible hydrogel (TR-HG), based on a modified polysaccharide with a thermo-reversible polyamide [poly(N-isopropylacrylamide), pNIPAM], which is made to behave as a liquid at room temperature and hardens at > 32 °C. In order to test the hydrogel, a papain-induced bovine caudal disc degeneration model (PDDM), creating a cavity in the NP, was employed. Human mesenchymal stem cells (hMSCs) or autologous bovine NP cells (bNPCs) were seeded in TR-HG; hMSCs were additionally preconditioned with rhGDF-5 for 7 days. Then, TR-HG was reversed to a fluid and the cell suspension injected into the PDDM and kept under static loading for 7 days. Experimental design was: (D1) fresh disc control + PBS injection; (D2) PDDM + PBS injection; (D3) PDDM + TR-HG (material control); (D4) PDDM + TR-HG + bNPCs; (D5) PDDM + TR-HG + hMSCs. Magnetic resonance imaging performed before and after loading, on days 9 and 16, allowed imaging of the hydrogel-filled PDDM and assessment of disc height and volume changes. In gel-injected discs the NP region showed a major drop in volume and disc height during culture under static load. The RT–PCR results of injected hMSCs showed significant upregulation of ACAN, COL2A1, VCAN and SOX9 during culture in the disc cavity, whereas the gene expression profile of NP cells remained unchanged. The cell viability of injected cells (NPCs or hMSCs) was maintained at over 86% in 3D culture and dropped to ~72% after organ culture. Our results underline the need for load-bearing hydrogels that are also cyto-compatible.

Assessment of the Matrix Degenerative Effects of MMP-3, ADAMTS-4 and HTRA1 injected into a bovine Intervertebral Disc Organ Culture Model

Study Design. In vitro study to develop an intervertebral disc degeneration (IDD) organ culture model, using coccygeal bovine intervertebral discs (IVDs) and injection of proteolytic enzymes MMP-3, ADAMTS-4 and HTRA1.Objective. This study aimed to develop an in-vitro model of enzyme-mediated IDD to mimic the clinical outcome in humans for investigation of therapeutic treatment options.Summary of Background Data. Bovine IVDs are comparable to human IVDs in terms of cell composition and biomechanical behavior. Researchers injected papain and trypsin into them to create an IDD model with a degenerated nucleus pulposus (NP) area. They achieved macroscopic cavities as well as a loss of glycosaminoglycans (GAGs). However, none of these enzymes are clinically relevant.Methods. Bovine IVDs were harvested maintaining the endplates. Active forms of MMP-3, ADAMTS-4 and HTRA1 were injected at a dose of 10μg/ml each. Phosphate buffered saline (PBS) was injected as a control. Discs were cultured for 8 days and loaded diurnally (day 1 to day 4 with 0.4 MPa for 16 h) and left under free swelling condition from day 4 to day 8 to avoid expected artifacts due to dehydration of the NP. Outcome parameters included disc height, metabolic cell activity, DNA content, glycosaminoglycan (GAG) content, total collagen content, relative gene expression and histological investigation.Results. The mean metabolic cell activity was significantly lower in the NP area of discs injected with ADAMTS-4 compared to the day 0 control discs. Disc height was decreased following injection with HTRA1, and was significantly correlated with changes in GAG/DNA of the NP tissue. Total collagen content tended to be lower in groups injected with ADAMTS4 and MMP-3.Conclusion. MMP-3, ADAMTS-4 and HTRA1 neither provoked visible matrix degradation nor major shifts in gene expression. However, cell activity was significantly reduced and HTRA1 induced loss of disc height which positively correlated with changes in GAG/DNA content. The use of higher doses of these enzymes or a combination thereof may therefore be necessary to induce disc degeneration

Subcutaneous infection model facilitates treatment assessment of secondary Alveolar echinococcosis in mice.

Alveolar echinococcosis (AE) in humans is a parasitic disease characterized by severe damage to the liver and occasionally other organs. AE is caused by infection with the metacestode (larval) stage of the fox tapeworm Echinococcus multilocularis, usually infecting small rodents as natural intermediate hosts. Conventionally, human AE is chemotherapeutically treated with mebendazole or albendazole. There is, however still the need for improved chemotherapeutical options. Primary in vivo studies on drugs of interest are commonly performed in small laboratory animals such as mice and Mongolian jirds, and in most cases, a secondary infection model is used, whereby E. multilocularis metacestodes are directly injected into the peritoneal cavity or into the liver. Disadvantages of this methodological approach include risk of injury to organs during the inoculation and, most notably, a limitation in the macroscopic (visible) assessment of treatment efficacy. Thus, in order to monitor the efficacy of chemotherapeutical treatment, animals have to be euthanized and the parasite tissue dissected. In the present study, mice were infected with E. multilocularis metacestodes through the subcutaneous route and were then subjected to chemotherapy employing albendazole. Serological responses to infection were comparatively assessed in mice infected by the conventional intraperitoneal route. We demonstrate that the subcutaneous infection model for secondary AE facilitates the assessment of the progress of infection and drug treatment in the live animal.

A Model for Family Preservation Case Assessment

The outcomes of family preservation practice have been researched and debated. The effectiveness of family preservation is still inconclusive and many of the findings may only be inferred to specific situations. Few studies have addressed the assessment techniques or outcome factors from a qualitative perspective. This article synthesizes current literature, research and practice, and proposes a practice framework with questioning techniques to assist practitioners in assessing the strengths and characteristics of a family, and making decisions on whether or not familybased services are appropriate for the family. Two actual cases are presented to illustrate how the worker can benefit from having the assessment data derived from this model.