Muscle transcriptome adaptations with mild eccentric ergometer exercise

The muscle has a wide range of possibilities to adapt its phenotype. Repetitive submaximal concentric exercise (i.e., shortening contractions) mainly leads to adaptations of muscle oxidative metabolism and endurance while eccentric exercise (i.e., lengthening contractions) results in muscle growth and gain of muscle strength. Modified gene expression is believed to mediate these exercise-specific muscle adjustments. In the present study, early alterations of the gene expression signature were monitored by a muscle-specific microarray. Transcript profiling was performed on muscle biopsies of vastus lateralis obtained from six male subjects before and in a 24-h time course after a single bout of mild eccentric ergometer exercise. The eccentric exercise consisted of 15 min of eccentric cycling at 50% of the individual maximal concentric power output leading to muscle soreness (5.9 on a 0-10 visual analogue scale) and limited muscle damage (1.7-fold elevated creatine kinase activity). Muscle impairment was highlighted by a transient reduction in jumping height after the eccentric exercise. On the gene expression level, we observed a general early downregulation of detected transcripts, followed by a slow recovery close to the control values within the first 24 h post exercise. Only very few regulatory factors were increased. This expression signature is different from the signature of a previously published metabolic response after an intensive endurance-type concentric exercise as well as after maximal eccentric exercise. This is the first description of the time course of changes in gene expression as a consequence of a mild eccentric stimulus.

Chemotherapeutic strategies against Trypanosoma brucei: drug targets vs. drug targeting

Trypanosoma brucei rhodesiense and T. b. gambiense are the causative agents of sleeping sickness, a fatal disease that affects 36 countries in sub-Saharan Africa. Nevertheless, only a handful of clinically useful drugs are available. These drugs suffer from severe side-effects. The situation is further aggravated by the alarming incidence of treatment failures in several sleeping sickness foci, apparently indicating the occurrence of drug-resistant trypanosomes. Because of these reasons, and since vaccination does not appear to be feasible due to the trypanosomes' ever changing coat of variable surface glycoproteins (VSGs), new drugs are needed urgently. The entry of Trypanosoma brucei into the post-genomic age raises hopes for the identification of novel kinds of drug targets and in turn new treatments for sleeping sickness. The pragmatic definition of a drug target is, a protein that is essential for the parasite and does not have homologues in the host. Such proteins are identified by comparing the predicted proteomes of T. brucei and Homo sapiens, then validated by large-scale gene disruption or gene silencing experiments in trypanosomes. Once all proteins that are essential and unique to the parasite are identified, inhibitors may be found by high-throughput screening. However powerful, this functional genomics approach is going to miss a number of attractive targets. Several current, successful parasiticides attack proteins that have close homologues in the human proteome. Drugs like DFMO or pyrimethamine inhibit parasite and host enzymes alike--a therapeutic window is opened only by subtle differences in the regulation of the targets, which cannot be recognized in silico. Working against the post-genomic approach is also the fact that essential proteins tend to be more highly conserved between species than non-essential ones. Here we advocate drug targeting, i.e. uptake or activation of a drug via parasite-specific pathways, as a chemotherapeutic strategy to selectively inhibit enzymes that have equally sensitive counterparts in the host. The T. brucei purine salvage machinery offers opportunities for both metabolic and transport-based targeting: unusual nucleoside and nucleobase permeases may be exploited for selective import, salvage enzymes for selective activation of purine antimetabolites.

Air bells of water spiders are an extended phenotype modified in response to gas composition

The water spider Argyroneta aquatica (Clerck) is the only spider that spends its whole life under water. Water spiders keep an air bubble around their body for breathing and build under-water air bells, which they use for shelter and raising offspring, digesting and consuming prey, moulting, depositing eggs and sperm, and copulating. It is unclear whether these bells are an important oxygen reservoir for breathing under water, or whether they serve mainly to create water-free space for feeding and reproduction. In this study, we manipulated the composition of the gas inside the bell of female water spiders to test whether they monitor the quality of this gas, and replenish oxygen if required. We exchanged the entire gas in the bell either with pure O(2), pure CO(2), or with ambient air as control, and monitored behavioural responses. The test spiders surfaced and replenished air more often in the CO(2) treatment than in the O(2) treatment, and they increased bell building behaviour. In addition to active oxygen regulation, they monitored and adjusted the bells by adding silk. These results show that water spiders use the air bell as an oxygen reservoir, and that it functions as an external lung, which renders it essential for living under water permanently. A. aquatica is the only animal that collects, transports, and stores air, and monitors its property for breathing, which is an adaptive response of a terrestrial animal to the colonization of an aquatic habitat. J. Exp. Zool. 307A:549-555, 2007. (c) 2007 Wiley-Liss, Inc.

Development of an optimization model for biofuel facility size and location and a simulation model for design of a biofuel supply chain

To mitigate greenhouse gas (GHG) emissions and reduce U.S. dependence on imported oil, the United States (U.S.) is pursuing several options to create biofuels from renewable woody biomass (hereafter referred to as “biomass”). Because of the distributed nature of biomass feedstock, the cost and complexity of biomass recovery operations has significant challenges that hinder increased biomass utilization for energy production. To facilitate the exploration of a wide variety of conditions that promise profitable biomass utilization and tapping unused forest residues, it is proposed to develop biofuel supply chain models based on optimization and simulation approaches. The biofuel supply chain is structured around four components: biofuel facility locations and sizes, biomass harvesting/forwarding, transportation, and storage. A Geographic Information System (GIS) based approach is proposed as a first step for selecting potential facility locations for biofuel production from forest biomass based on a set of evaluation criteria, such as accessibility to biomass, railway/road transportation network, water body and workforce. The development of optimization and simulation models is also proposed. The results of the models will be used to determine (1) the number, location, and size of the biofuel facilities, and (2) the amounts of biomass to be transported between the harvesting areas and the biofuel facilities over a 20-year timeframe. The multi-criteria objective is to minimize the weighted sum of the delivered feedstock cost, energy consumption, and GHG emissions simultaneously. Finally, a series of sensitivity analyses will be conducted to identify the sensitivity of the decisions, such as the optimal site selected for the biofuel facility, to changes in influential parameters, such as biomass availability and transportation fuel price. Intellectual Merit The proposed research will facilitate the exploration of a wide variety of conditions that promise profitable biomass utilization in the renewable biofuel industry. The GIS-based facility location analysis considers a series of factors which have not been considered simultaneously in previous research. Location analysis is critical to the financial success of producing biofuel. The modeling of woody biomass supply chains using both optimization and simulation, combing with the GIS-based approach as a precursor, have not been done to date. The optimization and simulation models can help to ensure the economic and environmental viability and sustainability of the entire biofuel supply chain at both the strategic design level and the operational planning level. Broader Impacts The proposed models for biorefineries can be applied to other types of manufacturing or processing operations using biomass. This is because the biomass feedstock supply chain is similar, if not the same, for biorefineries, biomass fired or co-fired power plants, or torrefaction/pelletization operations. Additionally, the research results of this research will continue to be disseminated internationally through publications in journals, such as Biomass and Bioenergy, and Renewable Energy, and presentations at conferences, such as the 2011 Industrial Engineering Research Conference. For example, part of the research work related to biofuel facility identification has been published: Zhang, Johnson and Sutherland [2011] (see Appendix A). There will also be opportunities for the Michigan Tech campus community to learn about the research through the Sustainable Future Institute.

Host- rather than virus-related factors reduce health-related quality of life in hepatitis C virus infection

BACKGROUND: Hepatitis C virus (HCV) infection is associated with decreased health-related quality of life (HRQOL). Although HCV has been suggested to directly impair neuropsychiatric functions, other factors may also play a role. PATIENTS AND METHODS: In this cross-sectional study, we assessed the impact of various host-, disease- and virus-related factors on HRQOL in a large, unselected population of anti-HCV-positive subjects. All individuals (n = 1736) enrolled in the Swiss Hepatitis C Cohort Study (SCCS) were asked to complete the Short Form 36 (SF-36) and the Hospital Anxiety Depression Scale (HADS). RESULTS: 833 patients (48%) returned the questionnaires. Survey participants had significantly worse scores in both assessment instruments when compared to a general population. By multivariable analysis, reduced HRQOL (mental and physical summary scores of SF-36) was independently associated with income. In addition, a low physical summary score was associated with age and diabetes, whereas a low mental summary score was associated with intravenous drug use. HADS anxiety and depression scores were independently associated with income and intravenous drug use. In addition, HADS depression score was associated with diabetes. None of the SF-36 or HADS scores correlated with either the presence or the level of serum HCV RNA. In particular, SF-36 and HADS scores were comparable in 555 HCV RNA-positive and 262 HCV RNA-negative individuals. CONCLUSIONS: Anti-HCV-positive subjects have decreased HRQOL compared to controls. The magnitude of this decrease was clinically important for the SF-36 vitality score. Host and environmental, rather than viral factors, seem to impact on HRQOL level.

Puma indirectly activates Bax to cause apoptosis in the absence of Bid or Bim

Bcl-2 family members regulate apoptosis in response to cytokine withdrawal and a broad range of cytotoxic stimuli. Pro-apoptotic Bcl-2 family members Bax and Bak are essential for apoptosis triggered by interleukin-3 (IL-3) withdrawal in myeloid cells. The BH3-only protein Puma is critical for initiation of IL-3 withdrawal-induced apoptosis, because IL-3-deprived Puma(-/-) cells show increased capacity to form colonies when IL-3 is restored. To investigate the mechanisms of Puma-induced apoptosis and the interactions between Puma and other Bcl-2 family members, we expressed Puma under an inducible promoter in cells lacking one or more Bcl-2 family members. Puma rapidly induced apoptosis in cells lacking the BH3-only proteins, Bid and Bim. Puma expression resulted in activation of Bax, but Puma killing was not dependent on Bax or Bak alone as Puma readily induced apoptosis in cells lacking either of these proteins, but could not kill cells deficient for both. Puma co-immunoprecipitated with the anti-apoptotic Bcl-2 family members Bcl-x(L) and Mcl-1 but not with Bax or Bak. These data indicate that Puma functions, in the context of induced overexpression or IL-3 deprivation, primarily by binding and inactivating anti-apoptotic Bcl-2 family members.

The basophil activation test in immediate-type drug allergy

Diagnosis of drug allergy involves first the recognition of sometimes unusual symptoms as drug allergy and, second, the identification of the eliciting drug. This is an often difficult task, as the clinical picture and underlying pathomechanisms are heterogeneous. In clinical routine, physicians frequently have to rely upon a suggestive history and eventual provocation tests, both having their specific limitations. For this reason both in vivo (skin tests) and in vitro tests are investigated intensively as tools to identify the disease-eliciting drug. One of the tests evaluated in drug allergy is the basophil activation test (BAT). Basophils with their high-affinity IgE receptors are easily accessible and therefore can be used as indicator cells for IgE-mediated reactions. Upon allergen challenge and cross-linking of membrane-bound IgE antibodies (via Fc-epsilon-RI) basophils up-regulate certain activation markers on their surface such as CD63 and CD203c, as well as intracellular markers (eg, phosphorylated p38MAPK). In BAT, these alterations can be detected rapidly on a single-cell basis by multicolor flow cytometry using specific monoclonal antibodies. Combining this technique with in vitro passive sensitization of donor basophils with patients' serum, one can prove the IgE dependence of a drug reaction. This article summarizes the authors' current experience with the BAT in the diagnostic management of immediate-type drug allergy mediated by drug-specific IgE antibodies.

The role of admission blood glucose in outcome prediction of surviving patients with multiple injuries

BACKGROUND: Recent literature demonstrates hyperglycemia to be common in patients with trauma and associated with poor outcome in patients with traumatic brain injury and critically ill patients. The goal of this study was to analyze the impact of admission blood glucose on the outcome of surviving patients with multiple injuries. METHODS: Patients' charts (age >16) admitted to the emergency room of the University Hospital of Berne, Switzerland, between January 1, 2002, and December 31, 2004, with an Injury Severity Score >or=17 and more than one severely injured organ system were reviewed retrospectively. Outcome measurements included morbidity, intensive care unit, and hospital length of stay. RESULTS: The inclusion criteria were met by 555 patients, of which 108 (19.5%) patients died. After multiple regression analysis, admission blood glucose proved to be an independent predictor of posttraumatic morbidity (p < 0.0001), intensive care unit, and hospital length of stay (p < 0.0001), despite intensified insulin therapy on the intensive care unit. CONCLUSIONS: In this population of patients with multiple injuries, hyperglycemia on admission was strongly associated with increased morbidity, especially infections, prolonged intensive care unit, and hospital length of stay independent of injury severity, gender, age, and various biochemical parameters.

Admission blood glucose is an independent predictive factor for hospital mortality in polytraumatised patients

PURPOSE: The goal of this study was to analyse a possible association of admission blood glucose with hospital mortality of polytraumatised patients and to develop an outcome prediction model for this patient group. METHODS: The outcome of adult polytraumatised patients admitted to the University Hospital of Berne, Switzerland, between 2002 and 2004 with an ISS > or = 17, and more than one severely injured organ system was retrospectively analysed. RESULTS: The inclusion criteria were met by 555 patients, of which 108 (19.5%) died. Hyperglycaemia proved to be an independent predictor for hospital mortality (P < 0.0001), following multiple regression analysis. After inclusion of admission blood glucose, the calculated mortality prediction model performed better than currently described models (P < 0.0001, AUC 0.924). CONCLUSION: In this retrospective, single-centre study in polytraumatised patients, admission blood glucose proved to be an independent predictor of hospital mortality following regression analysis controlling for age, gender, injury severity and other laboratory parameters. A reliable admission blood glucose-based mortality prediction model for polytraumatised patients could be established. This observation may be helpful in improving the precision of future outcome prediction models for polytraumatised patients. These observations warrant further prospective evaluation.

A versatile proline/alanine transporter in the unicellular pathogen Leishmania donovani regulates amino acid homoeostasis and osmotic stress responses

Unlike all other organisms, parasitic protozoa of the family Trypanosomatidae maintain a large cellular pool of proline that, together with the alanine pool, serve as alternative carbon sources as well as reservoirs of organic osmolytes. These reflect adaptation to their insect vectors whose haemolymphs are exceptionally rich in the two amino acids. In the present study we identify and characterize a new neutral amino acid transporter, LdAAP24, that translocates proline and alanine across the Leishmania donovani plasma membrane. This transporter fulfils multiple functions: it is the sole supplier for the intracellular pool of proline and contributes to the alanine pool; it is essential for cell volume regulation after osmotic stress; and it regulates the transport and homoeostasis of glutamate and arginine, none of which are its substrates. Notably, we provide evidence that proline and alanine exhibit different roles in the parasitic response to hypotonic shock; alanine affects swelling, whereas proline influences the rate of volume recovery. On the basis of our data we suggest that LdAAP24 plays a key role in parasite adaptation to its varying environments in host and vector, a phenomenon essential for successful parasitism.