Preconditioning Period Research Articles

Transstadial Transmission from Nymph to Adult of Coxiella burnetii by Naturally Infected Hyalomma lusitanicum.

Coxiella burnetii (Derrick) Philip, the causative agent of Q fever, is mainly transmitted by aerosols, but ticks can also be a source of infection. Transstadial and transovarial transmission of C. burnetii by Hyalomma lusitanicum (Koch) has been suggested. There is a close relationship between this tick species, wild animals and C. burnetii but the transmission in a natural environment has not been demonstrated. In this study, we collected 80 engorged nymphs of H. lusitanicum from red deer and wild rabbits. They moult to adults under laboratory conditions and we feed them artificially through silicone membranes after a preconditioning period. C. burnetii DNA was tested in ticks, blood and faeces samples using real-time PCR. The pathogen was found in 36.2% of fed adults, demonstrating that transstadial transmission from nymph to adult occurs in nature. The presence of DNA in the 60.0% of blood samples after artificial feeding confirms that adults transmit the bacteria during feeding. Further studies are needed about co-feeding and other possible transmission routes to define the role of this tick species in the cycle of C. burnetii.

Voluntary Exercise Suppresses Choroidal Neovascularization in Mice.

PurposeTo determine the effect of voluntary exercise on choroidal neovascularization (CNV) in mice.MethodsAge-matched wild-type C57BL/6J mice were housed in cages equipped with or without running wheels. After four weeks of voluntary running or sedentariness, mice were subjected to laser injury to induce CNV. After surgical recovery, mice were placed back in cages with or without exercise wheels for seven days. CNV lesion volumes were measured by confocal microscopy. The effect of wheel running only in the seven days after injury was also evaluated. Macrophage abundance and cytokine expression were quantified.ResultsIn the first study, exercise-trained mice exhibited a 45% reduction in CNV volume compared to sedentary mice. In the replication study, a 32% reduction in CNV volume in exercise-trained mice was observed (P = 0.029). Combining these two studies, voluntary exercise was found to reduce CNV by 41% (P = 0.0005). Exercise-trained male and female mice had similar CNV volumes (P = 0.99). The daily running distance did not correlate with CNV lesion size. Exercise only after the laser injury without a preconditioning period did not reduce CNV size (P = 0.41). CNV lesions of exercise-trained mice also exhibited significantly lower F4/80+ macrophage staining and Vegfa and Ccl2 mRNA expression.ConclusionsThese findings provide the first experimental evidence that voluntary exercise improves CNV outcomes. These studies indicate that exercise before laser treatment is required to improve CNV outcomes.

SMA syndrome: management perspective with laparoscopic duodenojejunostomy and long-term results.

Superior mesentery artery syndrome (SMAS) is a rare vasculo-anatomic occlusive pathologic entity for which a period of conservative medical management is advocated with surgery reserved for nonresponsive cases. We present our management plan that entails a single admission approach and complete rendering of medical and surgical treatment to the patient on a background of the socioeconomic and cultural trends prevalent in this geographic region. A retrospective analysis of 22 cases of SMAS admitted in our health care system who underwent a period of preoperative conditioning followed by laparoscopic duodenojejunostomy from September 2009 to June 2019 was performed. Patients were followed up at regular intervals. The mean follow-up of the cohort was 41.2months (2-108months). The median length of stay was 6days. The mean postoperative stay was 4.13days. A subgroup of six patients who had severe physiological depletion required a period of preoperative optimisation. Five of the 22 (22.7%) patients suffered from postoperative complications in the form of delayed return of bowel functions. None of the patients had complications more than Clavien-Dindo grade 2 with no mortality. Long-term data are available for 19 patients (86.3%) which showed no symptom recurrence. Management of SMAS that entails an antecedent medical therapy followed by surgery can be accomplished in a single admission with good to excellent results in the intermediate and long-term follow-up. Physiologically depleted patients do require a period of intensive preconditioning but on long-term follow-up, they have excellent results.

Partial discharge inception voltage of voids enclosed in epoxy/mica versus voltage frequency and temperature

Detection of partial discharges (PDs) is widely used as a condition assessment tool for high voltage equipment. Application of low frequency test voltage is often preferred in the case of test objects with a large capacitance. The question addressed here is how results from PD-measurements performed at low frequencies correspond to that occurring at 50 Hz power frequency. Different theoretical models for void voltage were examined and compared to experiments performed on laboratory samples of mica/epoxy, including embedded cylindrical voids. All test objects were preconditioned at 10 kV and 50 Hz for 5 min before partial discharge inception voltage (PDIV) testing by stepwise increasing the test voltage from 0 to 10 kV. The PDIV test was first completed at 300 Hz before being repeated at decreasing frequencies down to 0.1 Hz. The temperature was varied in the range of 20° to 155°C. The results at high frequencies showed that a pure capacitive model fits well to the measurements. Measured dielectric response in mica/epoxy explained the decreasing PDIV at low frequencies and high temperatures. A high PDIV was measured at a combination of low temperatures and low frequencies. This was correlated with a reduced void resistance of the electrically stressed void sidewalls caused by the PD activity during the preconditioning period. This indicates that the effect of PD by-products decays faster at higher temperatures. Values of PDIV are, therefore, expected to be dependent on both temperature and frequency.

The Nasal Microbiome As a Predictor of Infectious Complications after Hematopoietic Cell Transplant Patients

<h3>Introduction</h3> Hematopoietic cell transplantation (HCT) is a potentially curative treatment for a range of malignant and nonmalignant disorders. A common complication of HCT is the mucosal barrier injury that enables commensal microbes to invade underlying tissues and the bloodstream causing infections during the transplant period. Additionally, antibiotic use has a dramatic impact on the respiratory and intestinal microbiome by reducing the density and diversity of commensal flora and thus increasing the risk of acquiring drug resistant pathogens. <h3>Objectives</h3> To distinguish patients at risk of developing infections using nasal microbiome data and to evaluate the relationship of the nasal microbiome and different types of infections in the HCT population at our institution. <h3>Methods</h3> We conducted a prospective observational study. A total of 50 HCT patients were enrolled and blood, nasal washes and clinical data were collected at the preconditioning period (from day -14 of HCT up to 24 hours following initiation of conditioning regimen), every week for 8 weeks and every other week until week 14 post-HCT. Microbiome abundance prior to the infection's onset was analyzed. <h3>Results</h3> Patients were on average 56 years of age (range: 20-73) and the majority were white (n=40, 80%), male (n=34, 68%) and had leukemia (68%). Overall, patients experiencing any kind of infections had a different nasal microbiome than those without. An abundance of Stenotrophomonas in their nasal microbiome was associated with urinary tract infections and respiratory viral infections (FDR-Adj P value=0.009 and 0.004, respectively). Bacterial pneumonia occurred after an increase in Capnocytophaga was seen in the nasal microbiome (FDR-Adj P value=0.009) whereas fungal pneumonia occured after an increase in Pseudomonas, Methylobacterium, Lachnoclostridium, and Lactobacillus (FDR-Adj P value=0.01). Clostridium difficile gut colonization was observed following an increase in Dolosigranulum and Muribaculaceae in the nasal microbiome (FDR-Adj P value<0.0001) whereas Vancomycin-resistant enterococci colonization occurred after an increase in Muribaculaceae, Oblitimonas, Ignatzschineria, Lactobacillus, and Sporosarcina (FDR-Adj P value<0.007) (Figure). <h3>Conclusion</h3> Our findings provide important information on specific operational taxonomic unit abundances in the nasal microbiome and infections. The nasal microbiome could be key to predict infections in HCT recipients and design future interventions to prevent and reduce the morbidity and mortality related to infections in these high risk patients.

HLA-mismatched donor and high ferritin level showed poor clinical outcomes after allogeneic hematopoietic cell transplantation in patients with advanced myelofibrosis.

Background:Preconditioning intensity, donor choice and graft-versus-host disease (GVHD) prophylaxis of allogeneic hematopoietic cell transplantation (allo-HCT) for advanced myelofibrosis (MF) have not been fully elucidated.Methods:Thirty-five patients with advanced MF were treated with reduced-intensity conditioning (RIC) allo-HCT. We searched for matched sibling donors first, followed by matched or mismatched unrelated donors and familial mismatched donors. Preconditioning regimen consisted of fludarabine (total 150 mg/m2) and busulfan (total 6.4 mg/kg) with total body irradiation ⩽400cGy.Results:All showed engraftments, but four showed either leukemic relapse or delayed graft failure. Two-year overall survival (OS) and non-relapse mortality (NRM) was 60.0% and 29.9%, respectively. Acute GVHD was observed in 19 patients, and grade III–IV acute GVHD (eight grade III and four grade IV) was higher in human leukocyte antigen (HLA)-mismatched donor HCT compared with HLA-matched HCT (70% versus 20%). Chronic GVHD was observed in 16 patients, and a cumulative incidence of severe chronic GVHD was 33% in HLA-mismatched donor HCT and 7.7% in HLA-matched HCT. Significant hepatic GVHD was observed in nine patients (five acute, four chronic) and six of them died. Multivariate analysis revealed inferior OS in HLA-mismatched donor HCT (hazard ratio (HR) = 6.40, 95% confidence interval (CI) 1.6–25.7, p = 0.009) and in patients with high ferritin level at the time of pre-conditioning period (HR = 7.22, 95% CI 1.9–27.5, p = 0.004), which were related to higher incidence of hepatic GVHD with high NRM rate.Conclusion:RIC allo-HCT can be a valid choice providing graft-versus-fibrosis effect for advanced MF patients. However, HLA-mismatched donor and high pre-HCT ferritin level related to fatal hepatic GVHD should be regarded as poor-risk parameters.

The age-dependent effect of high-dose X-ray radiation on NFκB signaling, structure, and mechanical behavior of the intervertebral disc

ABSTRACTPurpose: Ionizing radiation damages tissue and provokes inflammatory responses in multiple organ systems. We investigated the effects of high-dose X-ray radiation on the molecular inflammation and mechanical function of the intervertebral disc (IVD).Methods: Functional spine units (FSUs) containing the vertebrae-IVDs-vertebrae structure extracted from 1-month, 6-month, and 16-month-old NFκB-luciferase reporter mice and from 6-month-old myeloid differentiation factor 88 (MyD88)-null mice. After a preconditioning period in culture, the FSUs were subjected a single dose of ionizing X-ray radiation at 20 Gys, and then NFκB expression was monitored. The IVDs were then subjected to mechanical testing using dynamic compression, glycosaminoglycan (GAG) quantification, and histological analyses.Results: In the 1-month-old FSUs, the NFκB-driven luciferase activity was significantly elevated for 1 day following the exposure to radiation. The 6-month-old FSUs showed increased NFκB activity for 3 days, while the 16-month-old FSUs sustained elevated levels of NFκB activity throughout the 10-day culture period. All irradiated groups showed significant loss of disc height, GAG content, mechanical function and changes in structure. Ablation of MyD88 blunted the radiation-mediated NFκB signaling, and preserved GAG content, and the IVDs’ structure and mechanical performance.Conclusions: These results suggest that high-dose radiation affects the IVDs’ NFκB-dependent inflammatory processes that subsequently lead to functional deterioration. Blocking the transactivation potential of NFκB via MyD88 ablation preserved the structure and mechanical function of the FSUs. The long-term effects of radiation on IVD homeostasis should be considered in individuals susceptible to occupational and medical exposure.

Adenosine and NMDA Receptors Modulate Neuroprotection-Induced NMDA Preconditioning in Mice.

The severity score of quinolinic acid (QA)-induced seizures was investigated after N-methyl-D-aspartate (NMDA) preconditioning associated with adenosine receptors. Also, the levels of adenosine A1 and A2A receptors and subunits of NMDA receptors in the hippocampi of mice were determined to define components of the resistance mechanism. Adult CF-1 mice were treated intraperitoneally with saline or NMDA (75mg/kg), and some mice were treated intracerebroventricularly (i.c.v.) with 0.1pmol of adenosine receptor antagonists 8-cyclopentyltheophylline (CPT; receptor A1) or ZM241385 (receptor A2A) 0, 1, or 6h after NMDA administration. These adenosine receptor antagonists were administered to block NMDA's protective effect. Seizures and their severity scores were evaluated during convulsions induced by QA (36.8nmol) that was administered i.c.v. 24h after NMDA. The cell viability and content of subunits of the NMDA receptors were analyzed 24h after QA administration. NMDA preconditioning reduced the maximal severity 6 displayed in QA-administered mice, inducing protection in 47.6% of mice after QA-induced seizures. CPT increased the latency of seizures when administered 0 or 6h, and ZM241385 generated the same effect when administered 6h after NMDA administration. The GluN1 content was lower in the hippocampi of the QA mice and the NMDA-preconditioned animals without seizures. GluN2A content was unaltered in all groups. The results demonstrated the components of resistance evoked by NMDA, in which adenosine receptors participate in a time-dependent mode. Similarly, the reduction on GluN1 expression in the hippocampus may contribute to this effect during the preconditioning period.

Time Development of Voltage Frequency Dependence of Partial Discharge Activity in Voids

Condition assessment of high voltage equipment based on partial discharge measurements is often performed after a voltage pre-conditioning period. The aim of this paper is to present results from experimental examinations of time variance of partial discharge activity and to propose physical explanations of the phenomena observed. Experiments were performed on laboratory made 3 mm thick discs of generator bar insulation, consisting of mica and glass fiber reinforced epoxy with a 0.5 mm thick cylindrical void surfaces of 10 mm in diameter. The effect of conducting and insulating void surfaces was examined using copper tape as upper and lower electrodes of the voids. All objects were tested by 12 one-minute long AC voltage frequency sweeps at frequencies from 50 Hz to 0.1 Hz distributed in time from start of the experiment, after initial one-hour constant 50 Hz voltage application and during object short-circuiting for 20 h. The main result shows that in case of insulating voids the apparent charges vanished after the one-hour constant 50 Hz voltage application. After a grounding period of 5 minutes, the charge magnitudes slowly increased with time until reaching steady state after about 4-8 hours. Test objects with conductive void surfaces showed such reduction in case of PD testing at 0.1 Hz only. At voltage frequencies above 10 Hz the measured PD magnitudes were found to be nearly constant, close to the expected high theoretical value. This indicate that PD by-products strongly affected the void resistivity and thereby affect the PD activity of insulating voids. These by-products are temporary and disappear with time.

Effect of supplementing a Saccharomyces cerevisiae fermentation product during a preconditioning period prior to transit on receiving period performance, nutrient digestibility, and antioxidant defense by beef steers.

: Forty-eight newly weaned crossbred beef steers from a single-source were used to determine the effects of feeding a Saccharomyces cerevisiae fermentation product (SCFP; NaturSafe, Diamond V) on receiving period performance, nutrient digestibility, and antioxidant defense. Seven days after arrival, steers were stratified by BW (257 ± 18 kg), sorted into pens (n = 1 pen/treatment), and pens assigned to dietary treatments: SCFP at 0 (CON), 12 (SCFP12), 18 (SCFP18), or 0 g·steer−1·d−1 during preconditioning (PRE; days −19 to 0), then 18 g·steer−1·d−1 during receiving (REC; days 0 to 58; CON18). On day −1 BW and blood were collected, steers were loaded onto a semitruck and transported 1,748 km over 19 h. Upon return, steers were weighed, stratified by BW within treatment and sorted into pens with GrowSafe bunks (n = 12 steers/treatment). Steers were weighed on days −1, 0, 29, 30, 57, and 58. Blood was collected from all steers on days −1, 1, and 8 and liver biopsies were performed on all steers on days −20, −3, and 59. Titanium dioxide was included as an indigestible marker in the diet of all steers from days 14 through 29 to determine total tract nutrient digestibility. Data were analyzed as a completely randomized design using ProcMixed of SAS with the fixed effect of treatment. Steer was the experimental unit for REC period variables. Contrast statements compared the linear and quadratic effects of feeding SCFP throughout the trial (CON, SCFP12, and SCFP18) and the effect of supplementation at 18 g·steer−1·d−1 for the entire trial or starting in REC (SCFP18 vs. CON18). Steers fed SCFP12 exhibited the greatest ADG and G:F from days 0 to 30 (quadratic P ≤ 0.04). Total tract digestibility of NDF and ADF was linearly decreased by SCFP (linear P ≤ 0.03). On day −3, SCFP12-fed steers tended to have the greatest liver concentrations of total, oxidized, and reduced glutathione (quadratic P = 0.06). Red blood cell lysate Mn:total-superoxide dismutase activity was 16% greater 1 d posttransit compared with pretransit values (day P ≤ 0.01). Timing of SCFP supplementation (SCFP18 vs. CON18) did not affect any of the variables assessed herein (P ≥ 0.19). Supplementing SCFP at 12 g·steer−1·d−1 tended to affect antioxidant capacity prior to transit and improved early receiving period performance; however, overall receiving period performance was not affected by SCFP supplementation. Further research is necessary to determine the optimal dose and timing of SCFP supplementation for beef cattle.

Full-time physioxic culture conditions promote MSC proliferation more than hypoxic preconditioning

Background & Aim Cells that are cultured and handled in traditional hyperoxic room air experience a dramatic shift in oxygen levels when injected in vivo. It has been reported that hypoxic pre-conditioning of mesenchymal stromal cells (MSC) in culture can increase cell survival in vivo after administration. Published hypoxic pre-treatments subject room-air expanded cells to lower oxygen atmospheric conditions for lengths of time that range from 15 minutes to 36 hours, followed by another period of high oxygen exposure in room air conditions before administration. Some regimens use cobalt compounds to deplete HIF-1a rather than the cell environment. We previously showed that Human bone marrow MSC yields are improved by enclosing cell-handling processes as well as incubation for a full-time controlled physioxic atmosphere. AIMs To use the Xvivo System (BioSpherix), with fully-enclosed and environmentally-controlled cell incubation and handling chambers, to compare different hypoxic pre-conditioning regimens to full-time physioxic conditions for MSC yields and subjected to subsequent physioxic conditions as if injected venously. Our null hypothesis was that the different culture conditions make no difference to MSC morphology and proliferation rates. Methods, Results & Conclusion MSC were incubated for 1-36 hours at 1% O2 before return to traditional supraphysioxic room air incubator oxygen levels for 24 hours. The cells were then incubated at 5% O2 (venous O2 levels) as if injected in vivo. These conditions were compared with unbroken 5% O2 for both cell handling and culture. Using an immersion oxygen probe, we recorded vessel headspace and pericellular medium oxygen levels during each regimen. For 72 hours in culture to 5% O2, we assayed cells for changes in cell division rates and final cell yield. MSC pericellular O2 levels lagged far behind atmospheric oxygen level changes, so MSC experienced low oxygen conditions for far less time than the pre-conditioning period. Unbroken oxygen conditions were more favorable for keeping MSC in the cell cycle than any pre-conditioning regiment, disproving the null hypothesis. We concluded that hypoxic pre-conditioning is not as favorable for MSC yields as full-time physioxic conditions for cell handling and incubation.

Biochar as a management tool for soilborne diseases affecting early stage nursery seedling production

Biochar is thought to have great potential as a supplemental amendment in nursery growing media. The knowledge of how to optimize the use of biochar in the nursery setting during the most vulnerable pre-emergence and early seedling stages of the plant, however, is underdeveloped. The current study involves pre-emergence trials in the Pythium aphanidermatum-cucumber pathosystem using a commercial nursery potting mixture amended with up to 3% w:w wood-derived biochar. The major questions were: (i) is pre-conditioning required to elicit suppression of pre-emergence damping-off disease in the Pythium-cucumber system; (ii) what are the changes in bacterial community composition and diversity due to pre-conditioning of the biochar-amended potting medium; and (iii) can the pre-conditioning stage be shortened from 45 days and still provide disease suppression. Pre-conditioning, consisting of pre-planting fertigation of the nursery medium, was found to be needed to achieve suppression of damping-off disease by biochar, with a reduction in pre-emergence damping-off caused by P. aphanidermatum by up to 71%. Illumina sequencing of 16s bacterial gene revealed a significant enrichment in the abundance of bacteria in general and potentially beneficial microorganisms in particular, as well as shifts in microbial community structure as a result of biochar addition. These changes may play an important role in the overall effects of biochar on disease suppression in young seedlings. A pre-conditioning period of only 14 days was found to be effective for disease suppression, which can substantially improve its practical utility for nurseries.

Consumption of a dark roast coffee blend reduces DNA damage in humans: results from a 4-week randomised controlled study.

To determine the DNA protective effects of a standard coffee beverage in comparison to water consumption. The single-blind, randomised controlled study with parallel design included healthy women (n = 50) and men (n = 50) recruited from the general Central European population. The subjects were randomised in a coffee and a control group, with stratification for sex and body mass index. The study comprised two periods of 4weeks: a preconditioning period, with daily consumption of at least 500ml water but no coffee, nor tea, nor any other caffeine-containing product. During the subsequent intervention period the coffee group consumed 500ml of freshly brewed dark roast coffee blend per day, the control group consumed water instead. On the last day of each period, blood was drawn and analysed by comet assay (single-cell gel electrophoresis) to assess the level of DNA damage (strand breakage). At the end of the intervention period the mean level of DNA strand breaks in the coffee group has decreased in comparison to the control group [difference in means 0.23% TI (tail intensity), p = 0.028]. The mean change from baseline (delta value) was - 23% in the coffee group (p = 0.0012). Effects of coffee intake were similar for men and women. During intervention, neither group showed any significant change in body weight or calorie intake. Our results indicate that regular consumption of a dark roast coffee blend has a beneficial protective effect on human DNA integrity in both, men and women.

Seasonal- and event-scale variations in upwelling, enrichment and primary productivity in the eastern Great Australian Bight

We used a suite of physical, chemical and biological datasets to assess the influence of upwelling/downwelling on enrichment and primary productivity in shelf waters of the eastern Great Australian Bight at seasonal and event scales. Results showed that the length of an upwelling season did not dictate its intensity or productivity, and that long seasons were not necessarily the most intense or productive. At the event scale, temperature and salinity were found to be better indicators of enrichment of shelf waters than wind stress, with temperatures < 15 °C and salinities < 35.6 psu associated with elevated concentrations of NOx (> 2 µm) and bursts of primary productivity (up to ∼ 700 mg C m−2 d−1). A key finding of this study was the importance of differentiating between upwelling events and enrichment events. The former occurred in the early upwelling season (November-December) and were demonstrated by periods of positive wind stress. The latter only occurred in the late upwelling season (January – April), and saw water with temperatures < 15 °C and salinities < 35.6 psu drawn onto the shelf and into the euphotic zone where it was available for primary producers. We used this information to develop a conceptual model which describes five different meteorological/oceanographic scenarios that occur in the eastern GAB, and their potential influence on enrichment and primary productivity, and hypothesise that total ecosystem productivity depends on the combination of these scenarios that occurs in the region in a given season/year. It is our contention that the early upwelling season represents a preconditioning period that plays a critical role in characterising late season enrichment events, and drives overall seasonal productivity.

Ischemic Preconditioning Preserves Liver Energy Charge and Function on Hepatic Ischemia/Reperfusion Injury in Rats

Cell energy during ischemia/reperfusion depends on mechanisms including adenosine diphosphate degradation, oxygen species and cytokine liberation, neutrophil infiltration, and endothelial dysfunction. Preconditioning-a brief ischemic episode that confers a state of protection against subsequent ischemia-reperfusion injury-involves NO and adenosine production, reduction in oxygen species liberation, and preservation of microcirculation. During hypoxia, constitutive NO production assures adequate oxygen delivery and reduced energy loss. The aim was to determine the role of ischemic preconditioning in the stimulation of constitutive endothelial nitric oxide (NO) production and its effect on energy charge, radical oxygen species generation, cytokine liberation, and neutrophil infiltration during reperfusion. Rats were assigned to one of four groups depending on the preconditioning protocol: hepatic ischemia/reperfusion, or hepatic ischemia/reperfusion and ischemic preconditioning, for 5, 10, or 20min. A portosystemic shunt was established between the portal and left jugular veins during ischemia. Preconditioning produced rises in plasma nitrites, but no rise in inducible nitric oxide synthase gene expression. A 5 or 10min preconditioning period allowed for higher energy charge, bile production, and glutathione levels, with less lipoperoxide, alanine aminotransferase, tumor necrosis factor-α, and interleukin-1 production and neutrophil infiltration, compared with 20min or control. Survival was 80% in the G10 group, 70 in G5, 10 in GC, and 0% in the G20 group. Ten-min liver preconditioning improves survival and prevents energy loss during hepatic ischemia/reperfusion by stimulating constitutive NO production, maintaining glutathione concentrations and reducing oxygen species and proinflammatory cytokine generation as well as neutrophil infiltration.

Implications of projected climate change on winter road systems in Ontario’s Far North, Canada

Understanding climate change impacts on winter road systems in Ontario’s Far North is critical due to the high dependence on such seasonal corridors by local residences, particularly among remote First Nations communities. In recent years, a warmer climate has resulted in a shorter winter road season and an increase in unreliable road conditions, thus limiting access among remote communities. This study focused on examining the future freezing degree day (FDD) accumulations during the preconditioning period of the winter roads at five locations using the multi-model ensembles of general circulation models (GCMs) and regional climate models (RCMs), under the representative concentration pathway (RCP) scenarios. The Statistical DownScaling Model Decision Centric Version 5 (SDSM-DC) was applied to validate the baseline climate. The results from the CMIP5 showed that by mid-century, the trends of FDDs under RCP4.5 for Moosonee and Kapuskasing were projected to decrease below the lowest threshold with the mean FDDs at 376 and 363, respectively. Under RCP8.5, the mean FDDs for Lansdowne House and Red Lake were projected to be below the lowest threshold, at 356 and 305, respectively, by the end of the century. Results of the FDD threshold measure indicated that climate conditions would possibly be unfavorable during the winter road construction period by mid-century for Moosonee and Kapuskasing and for Lansdowne House and Red Lake by the end of the century. For Big Trout Lake, on the other hand, climate conditions are expected to remain favorable for the winter road construction through the end of 2100.

Environmentally-realistic concentration of cadmium combined with polyunsaturated fatty acids enriched diets modulated non-specific immunity in rainbow trout

Nutrition is crucial to grow healthy fish particularly in a context of pollution, overcrowding and pathogen risks. Nowadays, the search for food components able to improve fish health is increasingly developing. Here, the influence of four dietary polyunsaturated fatty acids (PUFAs) that are alpha-linolenic acid (ALA, 18:3n-3), linoleic acid (LA, 18:2n-6), eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on the sensitivity of rainbow trout (Oncorhynchus mykiss) juveniles to environmentally realistic cadmium (Cd, 0.3 μg/L) concentration was investigated. Fish diets were designed to ensure the specific abundance of one of these individual PUFAs, and were given for a 4-week pre-conditioning period followed by a 6-week Cd exposure period. Focus was put on growth performance and immune responses following a short (24 h) and a long-term (6 weeks) Cd exposure. For each experimental condition, some fish were submitted to a bacterial challenge (24 h) with Aeromonas salmonicida achromogenes at the end of Cd conditioning period. DHA-enriched diet improved growth performances as compared to LA-enriched diet, but also increased ROS production (after short-term exposure to Cd) that could lead to a higher inflammation status, and some immunity-related genes (at short and long-term exposure). We notably highlighted the fact that even a low, environmentally-realistic concentration, Cd can strongly impact the immune system of rainbow trout, and that specific dietary PUFA enrichment strategies can improve growth performance (DHA-enriched diet), provide protection against oxidative stress (ALA- and EPA-enriched diet) and stimulate non-specific immunity.

Signal Mechanism of the Protective Effect of Combined Preconditioning by Amtizole and Moderate Hypoxia.

The content of regulatory proteins involved in adaptation to hypoxia and ischemia was studied in brain rat homogenate under conditions of normoxia and after bilateral ligation of the common carotid arteries. Preconditioning with amtizole in combination with moderate hypoxia increased the levels of HIF-1α, erythropoietin, vascular endothelial growth factor under conditions of normoxia. During experimental ischemia, combined preconditioning led to stabilization of the content of these regulatory proteins at the level of intact control and to a decrease in glycogen synthase-3β kinase activity. This pattern of changes in regulatory proteins was noted during the early and late periods of preconditioning.

Additional nutritional considerations for preconditioning beef calves.

Calves can be preconditioned using a wide variety of supplemental feed ingredients. However, feed ingredient selection is not the only factor to consider during a preconditioning process. Increasing the protein supply to stressed, preconditioning beef steers led to greater growth performance, and increased immune response to vaccination during a 42-day preconditioning period. Producers should not reduce the frequency of concentrate supplementation during the entire preconditioning period as it might lead to poorer vaccine response and average daily gain (consequently, less calf value at sale). However, a gradual reduction of frequency of supplementation is a supplementation strategy that can overcome these negative effects on growth and immunity, and allows producers to save on feeding and labor costs without producing lighter calves that have weaker immune responses.&#x0D;

Increased intrinsic stiffness and mineralization in femurs of adult rats after high intensity treadmill running training.

Physical activity plays a tremendous role in determining bone mechanical behavior, which is superimposed to gravidity. Compare the geometric and material responses of the rat femur to a high intensity treadmill running training of a relatively short duration, as assessed by 3-point mechanical test. Mature male rats (180.0± 30g) were assigned (7rats/group) to no exercise (NE) or treadmill exercise (EX). After a preconditioning period, the running speed was set at 45cm.seg-1 during 2wks, frequency 5d/wk, 2-hour sessions/day. Body weight and weight of the crural quadriceps were registered at euthanasia. The right femur was mechanically tested through 3-point bending. The left femur was ashed to estimate bone mineral content. Geometric and material bone properties were estimated directly or calculated by appropriate equations. 1)Final body weight was 14% reduced in EX rats, while the crural quadriceps was 47% increased. Yield and fracture loads, and structural stiffness were significantly higher in the EX rats, as were the apparent elastic modulus, the bone mineral content and the degree of mineralization. Geometric properties were not affected. High intensity treadmill running training increases bone strength and stiffness by increasing material stiffness and mineralization, without affecting geometric bone parameters.