Interplay between the QseC and QseE Bacterial Adrenergic Sensor Kinases in Salmonella enterica Serovar Typhimurium Pathogenesis

The bacterial adrenergic sensor kinases QseC and QseE respond to epinephrine and/or norepinephrine to initiate a complex phosphorelay regulatory cascade that modulates virulence gene expression in several pathogens. We have previously shown that QseC activates virulence gene expression in Salmonella enterica serovar Typhimurium. Here we report the role of QseE in S. Typhimurium pathogenesis as well as the interplay between these two histidine sensor kinases in gene regulation. An S. Typhimurium qseE mutant is hampered in the invasion of epithelial cells and intramacrophage replication. The ΔqseC strain is highly attenuated for intramacrophage survival but has only a minor defect in invasion. However, the ΔqseEC strain has only a slight attenuation in invasion, mirroring the ΔqseC strain, and has an intermediary intramacrophage replication defect in comparison to the ΔqseE and ΔqseC strains. The expressions of the sipA and sopB genes, involved in the invasion of epithelial cells, are activated by epinephrine via QseE. The expression levels of these genes are still decreased in the ΔqseEC double mutant, albeit to a lesser extent, congruent with the invasion phenotype of this mutant. The expression level of the sifA gene, important for intramacrophage replication, is decreased in the qseE mutant and the ΔqseEC double mutant grown in vitro. However, as previously reported by us, the epinephrine-dependent activation of this gene occurs via QseC. In the systemic model of S. Typhimurium infection of BALB/c mice, the qseC and qseE mutants are highly attenuated, while the double mutant has an intermediary phenotype. Altogether, these data suggest that both adrenergic sensors play an important role in modulating several aspects of S. Typhimurium pathogenesis.     

Environmental monitoring of ivermectin excreted in spring climatic conditions by treated cattle on dung fauna and degradation of faeces on pasture

The effect of ivermectin excreted in faeces of cattle treated in late winter on the arthropods and the degradation of faeces on pasture were evaluated. Four calves of similar age and weight were allocated to two groups, one group was treated subcutaneously with ivermectin and the other group remained as untreated control. From faeces collected from both groups at 3, 7, 14, 21 and 28 days post-treatment (dpt), three faecal pats of 1 kg each were made and deposited on a mixed paddock. One quarter of each faecal pat was removed at 10, 20, 30 and 60 days postdeposition (dpd) to determine the concentration of ivermectin, the organic matter content, and to collect colonising dung arthropods. Concentrations at days 3 and 7 pt were significantly higher than at the other dpt (p < 0.05). The highest ivermectin concentrations were found in samples from 3 dpt (p < 0.05). The organic matter percentage was not significantly different between treatments. An edaphic fauna characterised the colonisation of the faeces by organisms. Although arthropods’ abundance differences were not significant except for the 28 dpt at 30 dpd (p < 0.0003), fewer organisms were collected from the ivermectin group at all times.     

Role of different types of potassium channels and peroxisome proliferator-activated receptors γ in the antidepressant-like activity of bis selenide in the mouse tail suspension test

In the present study we investigated the role of potassium (K(+)) channels and peroxisome proliferator-activated receptor gamma (PPARγ) in the antidepressant-like effect of bis selenide in the mouse tail suspension test (TST). Intracerebroventricular (i.c.v.) pretreatment with tetraethyl ammonium (TEA, a non-specific inhibitor of K(+) channels, 25 pg/site), glibenclamide (an ATP-sensitive K(+) channel inhibitor, 0.5 pg/site), charybdotoxin (a large and intermediate conductance calcium-activated K(+) channel inhibitor, 25 pg/site) or apamin (a small-conductance calcium-activated K(+) channel inhibitor, 10 pg/site) produced a synergistic action with a sub effective dose of bis selenide (0.1 mg/kg, per oral--p.o.). Picrotoxin (1 mg/kg, intraperitoneally--i.p.) pretreatment did not prevent the reduction in immobility time elicited by bis selenide (1 mg/kg, p.o.) in the TST. The reduction in the immobility time elicited by an effective dose of bis selenide (1 mg/kg, p.o.) was prevented by the pretreatment of mice with cromakalim, minoxidil (K(+) channel openers, 10 μg/site, i.c.v.) and GW 9662 (a PPARγ antagonist, 10 μg/site, i.c.v.). The findings clearly suggest that an acute oral dose of bis selenide produced an antidepressant-like effect in the mouse TST by a mechanism that involves the K(+) channels and PPARγ receptors.     

Exhaled nitric oxide in severe obesity: effect of weight loss

Exhaled nitric oxide (NO) is a recognized biomarker in the lower respiratory tract. The effect of large variation in body mass on exhaled NO in the same individuals is not well known. The aim of the study was to evaluate both the effect of severe obesity and the influence of weight reduction on exhaled NO. A consecutive series of 24 uncomplicated obese patients (OB), who had laparoscopic adjustable gastric banding (LAGB) and 15 healthy controls (HC) were studied. Body mass index (BMI), exhaled NO and respiratory function tests were assessed. Exhaled NO was lower in obese in comparison to HC (12.0+/-3.6ppb versus 15.8+/-4.0ppb, p=0.0035). A significant positive correlation was found between exhaled NO and BMI in HC, which was not evident in OB. Among the respiratory indexes, functional residual capacity was significantly associated to exhaled NO. After 1 year, 12 obese patients undergone to LAGB were re-evaluated. Mean BMI (kg/m(2)) decreased from 44.8 before surgery to 32.3 post-operatively. The exhaled NO increased from 11.8+/-3.2ppb before surgery to 14.9+/-3.1ppb 1 year post-operatively (p=0.0023, n=12). In conclusion exhaled NO is consistently reduced in severe obesity and it is restored after weight reduction. The relationship between exhaled NO, large body mass excess and decrease of resting lung volume in severe obesity deserves further studies.     

Nitrergic Neurons in the Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)

Nitric oxide (NO) is a freely diffusible gaseous neurotransmitter generated by a selected population of neurons and acts as a paracrine molecule in the nervous system. NO is synthesized from l ‐arginine by means of the neuronal nitric oxide synthase (nNOS), an enzyme requiring nicotine adenine dinucleotide phosphate (NADPH) as cofactor. In this study, we used histochemical and immunohistochemical techniques to investigate the distribution of NADPH‐diaphorase (NADPH‐d) and nNOS in the spinal cord of the bottlenose dolphin (Tursiops truncatus). Cells with a fusiform‐shaped somata were numerous in the laminae I and II. The intermediolateral horn showed darkly‐stained cells with a multipolar morphology. Neurons with a multipolar or fusiform morphology were observed in the ventral horn. Multipolar and fusiform neurons were the most common cell types in lamina X. Nitrergic fibers were numerous especially in the dorsal and intermediolateral horns. The presence of nitrergic cells and fibers in different laminae of the spinal cord suggests that NO may be involved in spinal sensory and visceral circuitries, and potentially contribute to the regulation of the complex retia mirabilia. Anat Rec, 296:1603–1614, 2013. © 2013 Wiley Periodicals, Inc.     

Six weeks of aerobic training improves VO2max and MLSS but does not improve the time to fatigue at the MLSS

The purpose of this study was to investigate the effects of a 6-week aerobic training period on the time to fatigue (t _lim) during exercise performed at the maximal lactate steady state (MLSS). Thirteen untrained male subjects (TG; age 22.5 ± 2.4 years, body mass 72.9 ± 6.7 kg and VO_2max 44.9 ± 4.8 mL kg^?1 min^?1) performed a cycle ergometer test until fatigue at the MLSS power output before and after 6 weeks of aerobic training. A group of eight control subjects (CG; age 25.1 ± 2.4 years, body mass 70.1 ± 9.8 kg and VO_2max 45.2 ± 4.1 mL kg^?1 min^?1) also performed the two tests but did not train during the 6-week period. There were no differences between the groups with respect to the VO_2max or MLSS power output (MLSSw) before the treatment period. The VO_2max and the MLSSw of the TG increased by 11.2 ± 7.2 % (pre-treatment = 44.9 ± 4.8 vs. post-treatment = 49.8 ± 4.5 mL kg^?1 min^?1) and 14.7 ± 8.9 % (pre-treatment = 150 ± 27 vs. post-treatment = 171 ± 26 W), respectively, after 6 weeks of training. The results of the CG were unchanged. There were no differences in t _lim between the groups or within groups before and after training. Six weeks of aerobic training increases MLSSw and VO_2max, but it does not alter the t _lim at the MLSS.     

Isolation and expansion of thymus-derived regulatory T cells for use in pediatric heart transplant patients

Regulatory T-cells (Tregs) are a subset of T cells generated in the thymus with intrinsic immunosuppressive properties. Phase I clinical trials have shown safety and feasibility of Treg infusion to promote immune tolerance and new studies are ongoing to evaluate their efficacy. During heart transplantation, thymic tissue is routinely discarded providing an attractive source of Tregs. In this study, we developed a GMP-compatible protocol for expanding sorted thymus-derived CD3⁺CD4⁺CD25⁺CD127^– (Tregs) as well as CD3⁺CD4⁺CD25⁺CD127^–CD45RA⁺ (RA⁺Tregs) cells. We aimed to understand whether thymic RA⁺Tregs can be isolated and expanded offering an advantage in terms of stability as it has been previously shown for circulating adult CD45RA⁺ Tregs. We show that both Tregs and RA⁺Tregs could be expanded in large numbers and the presence of rapamycin is essential to inhibit the growth of IFN-γ producing cells. High levels of FOXP3, CTLA4, and CD25 expression, demethylation of the FOXP3 promoter, and high suppressive ability were found with no differences between Tregs and RA⁺Tregs. After freezing and thawing, all Treg preparations maintained their suppressive ability, stability, as well as CD25 and FOXP3 expression. The number of thymic Tregs that could be isolated with our protocol, their fold expansion, and functional characteristics allow the clinical application of this cell population to promote tolerance in pediatric heart transplant patients.     

Delayed physical and neurobehavioral development and increased aggressive and depression-like behaviors in the rat offspring of dams fed a high-fat diet

Early maternal exposure to a high-fat diet (HFD) may influence the brain development of rat offspring and consequently affect physiology and behavior. Thus, in the present study, we investigated the somatic, physical, sensory-motor and neurobehavioral development of the offspring of dams fed an HFD (52% calories from fat, mainly saturated) and the offspring of dams fed a control diet (CD – 14.7% fat) during lactation from the 1st to the 21st postnatal day (P). Maternal body weights were evaluated during lactation. In the progeny, somatic (body weight, head and lengths axes) and physical (ear unfolding, auditory conduit opening, eruption of the incisors and eye opening) development and the consolidation of reflex responses (palm grasp, righting, vibrissa placing, cliff avoidance, negative geotaxis, auditory startle response and free-fall righting) were determined during suckling. Depressive and aggressive behaviors were tested with the forced swimming test (FST) and the “foot-shock” test on days 60 and 110, respectively. The open field test was used to assess motor function. Compared to controls, the HFD-pups exhibited decreases in body weight (P7–P21) and body length (P4–P18), but by days P71 and P95, these pups were overweight. All indicators of physical maturation and the consolidation of the following reflexes, vibrissa placing, auditory startle responses, free-fall righting and negative geotaxis, were delayed in HFD-progeny. In addition, the pups from HFD dam rats also exhibited reduced swimming and climbing times in the FST and increased aggressive behavior. No changes in locomotion were observed. These findings show developmental and neurobehavioral changes in the rat offspring of dams fed the HFD during lactation and suggest possible disruption of physical and sensory-motor maturation and increased susceptibility to depressive and aggressive-like behavior.     

Computer-aided detection (CAD) in screening mammography: sensitivity of commercial CAD systems for detecting architectural distortion

OBJECTIVE: Computer-aided detection (CAD) algorithms have successfully revealed breast masses and microcalcifications on screening mammography. The purpose of our study was to evaluate the sensitivity of commercially available CAD systems for revealing architectural distortion, the third most common appearance of breast cancer. MATERIALS AND METHODS: Two commercially available CAD systems were used to evaluate screening mammograms obtained in 43 patients with 45 mammographically detected regions of architectural distortion. For each CAD system, we determined the sensitivity for revealing architectural distortion on at least one image of the two-view mammographic examination (case sensitivity) and for each individual mammogram (image sensitivity). Surgical biopsy results were available for each case of architectural distortion. RESULTS: Architectural distortion was deemed present and actionable by a panel of expert breast imagers in 80 views of the 45 cases. One CAD system detected distortion in 22 of 45 cases of distortion (case sensitivity, 49%) and in 30 of 80 mammograms (image sensitivity, 38%); it displayed 0.7 false-positive marks per image. Another CAD system identified distortion in 15 of 45 cases (case sensitivity, 33%) and 17 of 80 mammograms (image sensitivity, 21%); it displayed 1.27 false-positive marks per image. Sensitivity for malignancy-caused distortion was similar to or lower than sensitivity for all causes of distortion. CONCLUSION: Fewer than one half of the cases of architectural distortion were detected by the two most widely available CAD systems used for interpretations of screening mammograms. Considerable improvement in the sensitivity of CAD systems is needed for detecting this type of lesion. Practicing breast imagers who use CAD systems should remain vigilant for architectural distortion.