GABAergic Interneurons at Supraspinal and Spinal Levels Differentially Modulate the Antinociceptive Effect of Nitrous Oxide in Fischer Rats

Background: The study hypothesizes that nitrous oxide (N2O) releases opioid peptide in the brain stem, which results in inhibition of [gamma]-aminobutyric acid-mediated (GABAergic) neurons that tonically inhibit the descending noradrenergic inhibitory neurons (DNIN), resulting in activation of DNIN. In the spinal cord, activation of DNIN leads to the release of norepinephrine, which inhibits nociceptive processing through direct activation of [alpha]2 adrenoceptor and indirect activation of GABAergic neurons through [alpha]1 adrenoceptor. Arising from this hypothesis, it follows that GABAergic neurons will modulate the antinociceptive effect of N2O in diametrically opposite directions at supraspinal and spinal levels. The authors have tested this tenet and further examined the effect of midazolam, a GABA-mimetic agent, on N2O-induced antinociceptive effect.

Methods: Adult male Fischer rats were administered muscimol (GABAA receptor agonist) intracerebroventricularly (icv), gabazine (GABAA receptor antagonist) intrathecally (intrathecal), or midazolam intraperitoneally (intraperitoneal). Fifteen minutes later, they were exposed to air or 75% N2O and were subjected to the plantar test after 30 min of gas exposure. In some animals administered with midazolam, gas exposure was continued for 90 min, and the brain and spinal cord were examined immunohistochemically.

Results: The N2O-induced antinociceptive effect, which was attenuated by icv muscimol, intrathecal gabazine, and intraperitoneal midazolam. Midazolam inhibited N2O-induced c-Fos expression (a marker of neuronal activation) in the pontine A7 and spinal cord.     

TGF-β and IL-17 serum levels and specific immunotherapy

Two new T cell subsets may be involved in allergic rhinitis (AR) pathogenesis: Th17 and T regulatory cells, mainly producing IL-17 and TGF-β respectively. Successful Sublingual Immunotherapy (SLIT) induces relevant immunological changes, thus the aim of this study was to evaluate serum IL-17 and TGF-β levels in AR patients treated with SLIT for 2 years. Patients' blood samples were collected before initiating SLIT (baseline), three months after the end of the first pre-seasonal SLIT course, and at the end of the second pre-seasonal course. IL-17 was detectable only in the most severe allergic patients. SLIT significantly induced an increase in serum TGF-β levels. There was moreover a significant relationship between TGF-β and symptom severity and drug use at the end of the study. Therefore, this study provides clinically relevant evidence that two pre-seasonal SLIT courses may significantly affect serum TGF-β levels.     

Interleukin-7-engineered mesenchymal cells: in vitro effects on naive T-cell population.

T-cell homeostasis is regulated by several molecules; among these, interleukin (IL)-7 plays an essential role in the survival and homeostatic proliferation of peripheral naive T cells. In a previous study, we investigated whether human mesenchymal stromal cells (MSCs) could be engineered with the IL-7 gene to produce functional level of this cytokine. In the present study, we analyzed the impact of different quantities of IL-7 produced by MSCs on the survival and proliferation of a negative immunoselected naive (CD3(+)/CD45RA(+)) T-cell population. Co-cultivation of peripheral naive T cells with MSCs producing low (16 pg/mL) or high (1000 pg/mL) IL-7 levels or in the presence of exogenous IL-7 (0.01 ng/mL and 100 ng/mL) maintained the CD3(+)/CD45RA(+) naive T-cell phenotype. Chemokine receptor CCR7(+) expression was also maintained among this T-cell population. Naive T-cell molecular characteristics were maintained as assessed by the Vbeta spectratyping complexity score, which showed the maintenance of a broad T-cell repertoire. No Th1 or Th2 differentiation was observed, as assessed by interferon-gamma or IL-4 accumulation. In contrast, only MSCs producing high amounts of IL-7 caused increased activation (CD25 31.2% +/- 12% vs 10% +/- 3.5%; P < .05), proliferation (CD71 17.8+/-7% vs 9.3%+/-3, P < .05), apoptosis (assessed by annexin V: 18.6% +/- 5% vs 14.9% +/- 2.6%; P > .05), and the phase S cell cycle (15% vs 6.9%, P > .05). Exogenous IL-7 exhibited no significant effect. In conclusion, we demonstrated that IL-7 produced by MSCs has a dose-independent effect on naive T-cell survival while exerting a dose-dependent effect on activation/proliferation. Due to the continuous production of IL-7 by engineered cells, our system is more efficacious than exogenous IL-7.     

Sodium hypochlorite-, chlorine dioxide- and peracetic acid-induced genotoxicity detected by the Comet assay and Saccharomyces cerevisiae D7 tests

Mutagenicity of drinking water is due not only to industrial,agricultural and urban pollution but also to chlorine disinfectionby-products. Furthermore, residual disinfection is used to providea partial safeguard against low level contamination and bacterialre-growth within the distribution system. The aims of this studywere to further evaluate the genotoxic potential of the worldwide used disinfectants sodium hypochlorite and chlorine dioxidein human leukocytes by the Comet assay and in Saccharomycescerevisiae strain D7 (mitotic gene conversion, point mutationand mitochondrial DNA mutability, with and without endogenousmetabolic activation) and to compare their effects with thoseof peracetic acid, proposed as an alternative disinfectant.All three disinfectants are weakly genotoxic in human leukocytes(lowest effective dose 0.2 p.p.m. for chlorine dioxide, 0.5p.p.m. for sodium hypochlorite and peracetic acid). The resultsin S.cerevisiae show a genotoxic response on the end-pointsconsidered with an effect only at doses higher (5- to 10-fold)than the concentration normally used for water disinfection;sodium hypochlorite and peracetic acid are able to induce genotoxiceffects without endogenous metabolic activation (in stationaryphase cells) whereas chlorine dioxide is effective in growingcells. The Comet assay was more sensitive than the yeast tests,with effective doses in the range normally used for water disinfectionprocesses. The biological effectiveness of the three disinfectantson S.cerevisiae proved to be strictly dependent on cell-specificphysiological/biochemical conditions. All the compounds appearto act on the DNA and peracetic acid shows effectiveness similarto sodium hypochlorite and chlorine dioxide. ¹Author to whom correspondence should be addressed. Tel: +39 0521 905608; Fax: +39 0521 905604; Email: mutgen{at}unipr.it Received on September 22, 2003; revised and accepted on November 27, 2003     

Efficacy of oral administration and oral intake of edible vaccines

To evaluate whether vaccine administration via intragastric gavage is indicative for the outcome of edible vaccines, mice were orally immunised with ovalbumin (OVA) mixed with or without Vibrio cholerae toxin (CT) in various compositions via various routes: (1) OVA dissolved in saline and intragastrically (IG) administered ('IG'); (2) OVA mixed with food extract and administered IG ('food IG'); (3) food chow absorbed with OVA dissolved in saline and fed to the animals ('food'); and (4) OVA dissolved in saline and administered via drinking bottles ('drinking'). When given to naive mice, 'IG' and 'food IG' but not 'food' or 'drinking' induced anti-OVA IgG1 responses in serum, but oral boost immunisations were necessary. Serum IgA was not induced. Oral boosting of subcutaneously (SC) primed mice enhanced the IgG1 and IgA response in serum regardless of the route of immunisation or the vaccine composition. CT did not dramatically enhance the immune response. All immunisation routes except 'drinking' induced antigen-specific IgA antibody secreting cells (ASC) in the lamina propria of naive mice. But antigen-specific antibody responses in faeces were not observed. We concluded that oral (i.e. IG) administration is distinct from oral intake. The composition of the vaccine (food or saline) did not influence oral administration. We thus suggested that the route of administration greatly influenced the outcome of oral immunisation. Although oral administration is a well-accepted route to test the potentials of oral vaccines, our study demonstrated that it is merely indicative for the effectiveness of edible vaccines. Studies on the feasibility of edible vaccines should thus be performed by eating the vaccine.     

Cytokine pattern in allergic and non-allergic chronic rhinosinusitis in asthmatic children

BACKGROUND: Rhinosinusitis represents one of the most common chronic diseases. The association of rhinosinusitis with asthma has been frequently reported. Eosinophils and Th2 cells play a pathogenic mechanism in asthma. OBJECTIVE: The aims of the study were to evaluate the cytokine pattern in chronic rhinosinusitis in asthmatic children and to compare the findings in allergic vs. non-allergic asthmatics. METHODS: Thirty-five asthmatic children were evaluated, 19 males and 16 females, with an average age of 8.7 years. All children were asthmatic and suffered from chronic rhinosinusitis. Twenty were allergic and 15 were non-allergic. Ten healthy children were studied as normal controls. Evaluated parameters were the levels of the following cytokines: IL-1beta, IL-4, IL-6, IL-8, IL-12, IFN-gamma and TNF-alpha. Cytokines were recovered from rhinosinusal lavage and measured by immunoassays. Nasal cytology was also performed in all subjects and inflammatory cells were counted by conventional staining. RESULTS: Allergic subjects showed a significant increase of IL-4 (P < 0.01) and TNF-alpha (P < 0.05) and a significant decrease of IL-12 (P < 0.05) and of IFN-gamma (P < 0.0001), whereas IL-1beta, IL-6 and IL-8 were not significantly increased. Non-allergic children showed a significant increase of IL-4 (P < 0.05) and a significant decrease of IFN-gamma (P < 0.0001), IL-12 was not significantly decreased, and IL-1beta, IL-6 and IL-8 were not significantly increased. A significant inflammatory infiltrate was present in all asthmatic children. Significant correlations were demonstrated between IL-4 and IL-12 (P < 0.001), IL-12 and IFN-gamma (P < 0.001), IL-8 and neutrophils (P < 0.01), and TNF-alpha and monocytes/macrophages (P < 0.05), in allergic asthmatics. IL-4 and IL-12 were significantly correlated (P < 0.05) as well as IL-8 and neutrophils (P < 0.01) in non-allergic asthmatics. CONCLUSION: This study shows that allergic asthmatic children with chronic rhinosinusitis have a typical Th2 cytokine pattern, but also non-allergic asthmatic children share a similar pattern. These findings would suggest the existence of a common pathophysiological mechanism shared by upper and lower airways and are consistent with the concept of united airways disease.     

Relationships between allergic inflammation and nasal airflow in children with persistent allergic rhinitis due to mite sensitization

BACKGROUND: Allergic rhinitis is associated with Th2-dependent inflammation. Nasal obstruction is the most typical symptom in children with mite allergy. OBJECTIVES: The aim of this study was to evaluate the possible relationships among nasal symptoms, allergic inflammation, including inflammatory cells and cytokine pattern, and nasal airflow in children with persistent allergic rhinitis because of mite sensitization. METHODS: Twenty children (13 males and seven females, mean age 13.4 +/- 1.6 years) with persistent rhinitis because of mite allergy were evaluated. All of them had moderate-severe grade of nasal obstruction. Total symptom score (TSS), rhinomanometry, nasal lavage, and nasal scraping were obtained in all subjects. Inflammatory cells were counted by conventional staining; interleukin (IL)-5, and IL-8 were measured by immunoassay on fluids recovered from nasal lavage. RESULTS: Eosinophils were significantly associated with TSS (R = 74.4%, P = 0.0002), with IL-5 (R = 90.6%, P < 0.0001) and with nasal flow (R = -69%, P = 0.0007), but not with IL-8 (R = 0.1%, P = 0.995). Eosinophil levels were shown to independently predict nasal flow (P < 0.001), with flow decreasing linearly for increasing eosinophils, together with a significant effect of neutrophils (P = 0.016, linear increase in flow) and a borderline effect of IL-8 (P = 0.063, linear increase in flow). CONCLUSIONS: This study demonstrates the close association between IL-5 concentration and eosinophil infiltration. In addition, there is clear evidence concerning the relationship between eosinophil infiltration and nasal airflow. Thus, nasal eosinophils can be regarded as the most important predictor of upper airway function. These findings constitute first evidence of the relationship between nasal airflow impairment and Th2-related eosinophilic inflammation in children with persistent allergic rhinitis because of mite sensitization.     

How does yoga reduce stress? A clinical trial testing psychological mechanisms

Yoga interventions can reduce stress, but the mechanisms underlying that stress reduction remain largely unidentified. Understanding how yoga works is essential to optimizing interventions. The present study tested five potential psychosocial mechanisms (increased mindfulness, interoceptive awareness, spiritual well-being, self-compassion and self-control) that have been proposed to explain yoga's impact on stress. Forty-two participants (62% female; 64% White) in a yoga program for stress reduction completed surveys at baseline (T1), mid-intervention (T2) and post-intervention (12 weeks; T3). We measured two aspects of stress, perceived stress and stress reactivity. Changes were assessed with paired t-tests; associations between changes in mechanisms were tested in residual change models. Only stress reactivity decreased, on average, from T1 to T3. Except for self-compassion, all psychosocial mechanisms increased from T1 to T3, with minimal changes from T2 to T3. Except for self-control, increases in each mechanism were strongly associated with decreases in both measures of stress between T1 and T2 and decreases in perceived stress from T1 to T3 (all p's < 0.05). Increased psychosocial resources are associated with stress reduction. Yoga interventions targeting these resources may show stronger stress reduction effects. Future research should test these linkages more rigorously using active comparison groups and larger samples.