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1.
Article in English | MEDLINE | ID: mdl-36982009

ABSTRACT

Waste sorting is a practical way of handling the garbage and an effective strategy for facilitating sustainable waste management. This research extended the theory of planned behavior (TPB) with self-identity and moral norms to predict waste sorting intentions in a heritage context of tourism. A total of 403 valid self-administrated questionnaires were achieved at a heritage destination in China. The results indicated that: (1) TPB variables (i.e., attitudes toward the behavior, subjective norms, and perceived behavioral control), self-identity, and moral norms were all directly and positively linked to tourists' waste sorting intentions, respectively; (2) self-identity indirectly influenced tourists' waste sorting intentions through the mediation of moral norms; and (3) the integrated model exhibited better predictive utility than any single model. This research contributes to the literature on waste management in the context of tourism by extending TPB with identity and personal normative constructs. It also provides practical implications for destination managers to leverage tourists' self-identity and moral norms for sustainable management.


Subject(s)
Intention , Waste Management , Theory of Planned Behavior , Attitude , Surveys and Questionnaires
2.
Tour Manag Perspect ; 46: 101087, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36741920

ABSTRACT

The effect of hotel employee resilience during major crises lacks sufficient empirical investigation. This research aimed to develop a conceptual model of hotel employee resilience effects on turnover intentions and service quality with belief restoration as mediation and challenge stressors and perceived risk as moderation variables. A questionnaire survey was conducted with 28 star-rated hotels (including two 3-star, fifteen 4-star, and eleven 5-star hotels) in southeastern, northeastern, central, and western China against the background of the COVID-19 pandemic, and with operational (e.g., front office, food and beverage, housekeeping) and administrative (e.g., human resource, sales, finance) departments. A total of 1318 valid questionnaires were collected. The results showed that: (1) employee resilience predicted employee service quality positively and turnover intentions negatively; (2) belief restoration partially mediated the impact of employee resilience on service quality and turnover intentions; and (3) perceived risk and challenge stressors had diverse moderation effects (e.g., U-shaped, linear) in the impacts of resilience, and they were important external and internal situational factors that influenced the impact of employee resilience. This research revealed the effects and situational conditions of hotel employee resilience during a major crisis, which provides a theoretical basis for establishing hotel crisis response strategies.

3.
Article in English | MEDLINE | ID: mdl-36674103

ABSTRACT

How to save resources and protect the environment at destinations is one of the hot issues in tourism. One effective solution is to cultivate tourist resource-saving behavioral intentions (TRSBI). Prior studies mainly use Structural equation modeling (SEM) to explore its antecedents, whereas other potential methods (i.e., fuzzy-set qualitative comparative analysis, fsQCA for short) have been less adopted. This study combines SEM and fsQCA to examine TRSBI in a rural tourism context. Specifically, SEM is executed to investigate how environmental concern influences TRSBI based on the theory of planned behavior (TPB), while fsQCA is applied to uncover the multiple configurations in the TRSBI formation. The findings from SEM indicated that (1) environmental concern positively and directly influenced TRSBI; (2) TPB constructs (i.e., attitudes toward the behavior, subjective norms, and perceived behavioral control) positively and separately mediated the associations of environmental concern with TRSBI. The fsQCA outcomes showed that three configurations result in a high level of TRSBI: (1) high attitudes toward the behavior, subjective norms, and perceived behavioral control, (2) high attitudes toward the behavior, subjective norms, and environmental concern, and (3) high attitudes toward the behavior, perceived behavioral control, and environmental concern. The combined approaches offer a systematic and holistic solution to explore TRSBI in rural tourism.


Subject(s)
Intention , Theory of Planned Behavior , Humans , Latent Class Analysis , Tourism , Surveys and Questionnaires
4.
Med Humanit ; 49(3): 497-499, 2023 Sep.
Article in English | MEDLINE | ID: mdl-36697217

ABSTRACT

This review considers recent challenges to, and changes within, narrative medicine as a paradigm for humanities-based medical education. It suggests that, while narrative medicine has often been criticised for emphasising narrative at the expense of other dimensions of human experience, newer criticism has focused more on its relationship with other areas of medical knowledge. In different ways, recent work has shown greater interest in taking in humanities perspectives on their own terms, rather than (this is the charge against narrative medicine) instrumentalising them as diagnostic tools. The review concludes by considering how these criticisms might make their way into the institutional realities of medical education, as well as what they might learn from narrative medicine's success.


Subject(s)
Education, Medical , Narrative Medicine , Humans , Humanities/education , Narration , Knowledge
5.
Article in English | MEDLINE | ID: mdl-36554447

ABSTRACT

Residents' environmental citizenship behavior is essential to the environmental protection and sustainable development of rural destinations. However, previous research with regards to environmental citizenship behavior has focused on an employee perspective, rather than a resident one. Through the theoretical lens of the Stimulus-Organism-Response (SOR) model, our research examined how perceived environmental CSR (ECSR) contributes to residents' environmental citizenship behavior, with resident-environment relationship quality acting as the organism. Data collected from a Chinese rural destination were analyzed with a structural equation modeling approach. Results indicate that: (1) perceived ECSR directly and positively influences residents' environmental citizenship behavior; (2) relationship quality variables (i.e., environmental identification and environmental commitment) directly and positively affect residents' environmental citizenship behavior; (3) environmental identification directly and positively affects environmental commitment; (4) relationship quality variables positively mediate the effect of perceived ECSR on residents' environmental citizenship behavior. The current research complements existing tourism literature on environmental citizenship behavior with a focus on perceived ECSR and relationship quality from the aspect of residents in rural destinations. The findings also provide some practical implications that potentially facilitate the adoption of environmental citizenship behavior among residents for sustainable destination management.


Subject(s)
Citizenship , Tourism , Humans , Conservation of Natural Resources , Rural Population , Surveys and Questionnaires
6.
SN Bus Econ ; 2(11): 169, 2022.
Article in English | MEDLINE | ID: mdl-36246096

ABSTRACT

The aim of this research was to examine the long- and short-run relationships among real expenditures on outbound tourism from China, economic growth and international trade for the period of 1995 to 2018, applying a newly developed cointegration test-the Bootstrap Autoregressive Distributed Lag framework. Evidence of cointegration was found when expenditures on outbound tourism served as the dependent variable, and economic growth and international trade were important factors affecting outbound tourism from China. For the short-run, a two-way Granger causality relationship was detected between economic growth and outbound tourism expenditures, and the feedback was confirmed between outbound tourism expenditures and international trade. The findings have important policy implications for the growth of the outbound tourism market. Large volumes of outbound tourists result in economic losses for China and outbound tourism reduces the growth of tourism-driven international trade.

7.
Article in English | MEDLINE | ID: mdl-36232090

ABSTRACT

Improper waste disposal of tourists has detrimental impacts on the environment, economy, and people in rural destinations. Separating at the source is an effective means to mitigate these adverse impacts on rural destinations. Hence, identifying factors influencing tourists' waste sorting intentions in rural destinations is critical to the sustainability of rural tourism and rural land. However, few studies focus on tourists' waste sorting intentions. Drawing on the theory of planned behavior (TPB) and social capital, this research examined the determinants of tourists' waste sorting intentions in rural destinations. A total of 395 valid questionnaires were collected from a rural destination in Huzhou, China. The results indicated that: (1) all TPB variables, i.e., attitude toward the behavior, subjective norms, and perceived behavioral control, positively and directly affect tourists' waste sorting intentions; (2) interpersonal trust directly and positively influences tourists' waste sorting intentions; (3) subjective norms, perceived behavioral control, interpersonal trust, and emotional bonding indirectly influence tourists' waste sorting intentions through the mediation of attitude toward the behavior; (4) emotional bonding does not directly affect tourists' waste sorting intentions, but the link is established through the mediation of attitude toward the behavior. This research expands the body of knowledge by integrating individuals' psychological elements with their social contexts. The findings offer some theoretical and managerial implications for understanding how tourists' social contexts facilitate tourists' waste sorting intentions.


Subject(s)
Intention , Social Capital , Attitude , China , Humans , Rural Population
8.
Article in English | MEDLINE | ID: mdl-34886575

ABSTRACT

This research analyzed the impact of environmental regulations and their power in suppressing tourism carbon emissions. The results showed that: (1) four types of environmental regulations had significant inhibiting effects on tourism carbon emissions, but different types of regulations had varying effects; and (2) environmental regulations had a significant time lag effect on tourism carbon emissions. The decay rates of the environmental regulation effects were dissimilar for supervisory management, market incentives, command and control, and public participation; and (3) environmental regulations had dissimilar influences on tourism carbon emissions at the regional level. Government agencies should choose differentiated environmental regulation tools, attach great importance to the time-lag effect of environmental regulations on tourism carbon emissions, and establish systems and mechanisms of public participation in environmental matters.


Subject(s)
Carbon , Economic Development , Carbon Dioxide , Climate , Tourism
9.
Article in English | MEDLINE | ID: mdl-34682622

ABSTRACT

Medical, health and wellness tourism and travel represent a dynamic and rapidly growing multi-disciplinary economic activity and field of knowledge. This research responds to earlier calls to integrate research on travel medicine and tourism. It critically reviews the literature published on these topics over a 50-year period (1970 to 2020) using CiteSpace software. Some 802 articles were gathered and analyzed from major databases including the Web of Science and Scopus. Markets (demand and behavior), destinations (development and promotion), and development environments (policies and impacts) emerged as the main three research themes in medical-health-wellness tourism. Medical-health-wellness tourism will integrate with other care sectors and become more embedded in policy-making related to sustainable development, especially with regards to quality of life initiatives. A future research agenda for medical-health-tourism is discussed.


Subject(s)
Medical Tourism , Tourism , Bibliometrics , Policy , Quality of Life
10.
Mol Ther ; 27(10): 1706-1717, 2019 10 02.
Article in English | MEDLINE | ID: mdl-31526597

ABSTRACT

The field of cell and gene therapy (GT) is expanding rapidly and there is undoubtedly a wave of enthusiasm and anticipation for what these treatments could achieve next. Here we assessed the worldwide landscape of GT assets currently in early clinical development (clinical trial phase 1/2 or about to enter clinical trial). We included all gene therapies, i.e., strategies that modify an individual's protein make-up by introducing exogenous nucleic acid or nucleic acid modifiers, regardless of delivery. Unmodified cell therapies, oncology therapies (reviewed elsewhere), and vaccine programs (distinct therapeutic strategy) were not included. Using a December 31, 2018 cutoff date, we identified 336 gene therapies being developed for 138 different indications covering 165 genetic targets. In all, we found that the early clinical GT landscape comprises a very disparate group of drug candidates in terms of indications, organizations, and delivery methods. We also highlight interesting trends, revealing the evolution of the field toward in vivo therapies and adeno-associated virus vector-based delivery systems. It will be interesting to witness what proportion of this current list effectively translates into new medicines.


Subject(s)
Drug Delivery Systems/classification , Genetic Therapy/methods , Clinical Trials as Topic , Genetic Vectors/administration & dosage , Humans , Molecular Targeted Therapy
11.
Nordisk Alkohol Nark ; 34(4): 314-329, 2017 Aug.
Article in English | MEDLINE | ID: mdl-32934494

ABSTRACT

INTRODUCTION: Alcohol ranks as a major risk factor for health-related harm and mortality. Older males who encounter alcohol problems late in life are an under-studied part of the affected population. This article seeks to broaden our understanding of this group by combining empirical data with humanistic cultural analysis. Specifically, it seeks to show how the desire to cope alone can be linked to generationally specific constructions of hegemonic masculinity. METHOD: Clinical empirical methods are fused here with those of literary analysis. The subjects which the clinical researcher chooses for scrutiny are different from those most natural to literary study, yet the interpretive approaches of qualitative phenomenological investigation and literary close reading are in fact quite similar, and we argue that new knowledge can be generated by evaluating cultural texts alongside the testimony of phenomenological research subjects. FINDINGS AND DISCUSSION: Our findings illustrate a thematic connection between subject testimony and literary texts from the relevant historical period. In the sources we compared - a qualitative study conducted in Denmark and a British novel, Kingsley Amis's 1954 Lucky Jim - we found a strong link between the values of masculinity and the values of independence. Older men's resistance of institutional treatment for alcohol problems has motivations which go beyond the desire not to rely on outside aid, a desire which may apply to any illness. As Lucky Jim helps us show, alcohol use functions for men of a certain generation as a symbol of rebellion against institutions, and having institutions play a dominant role in their alcohol cessation may create resistance in these men.

12.
Neuropsychopharmacology ; 42(6): 1349-1360, 2017 May.
Article in English | MEDLINE | ID: mdl-27986973

ABSTRACT

Dysbindin-1, a protein that regulates aspects of early and late brain development, has been implicated in the pathobiology of schizophrenia. As the functional roles of the three major isoforms of dysbindin-1, (A, B, and C) remain unknown, we generated a novel mutant mouse, dys-1A-/-, with selective loss of dysbindin-1A and investigated schizophrenia-related phenotypes in both males and females. Loss of dysbindin-1A resulted in heightened initial exploration and disruption in subsequent habituation to a novel environment, together with heightened anxiety-related behavior in a stressful environment. Loss of dysbindin-1A was not associated with disruption of either long-term (olfactory) memory or spontaneous alternation behavior. However, dys-1A-/- showed enhancement in delay-dependent working memory under high levels of interference relative to controls, ie, impairment in sensitivity to the disruptive effect of such interference. These findings in dys-1A-/- provide the first evidence for differential functional roles for dysbindin-1A vs dysbindin-1C isoforms among phenotypes relevant to the pathobiology of schizophrenia. Future studies should investigate putative sex differences in these phenotypic effects.


Subject(s)
Attention/physiology , Behavior, Animal/physiology , Dysbindin/physiology , Memory, Short-Term/physiology , Schizophrenia/physiopathology , Animals , Disease Models, Animal , Female , Male , Memory, Long-Term/physiology , Mice , Mice, Transgenic , Olfactory Perception/physiology , Phenotype , Protein Isoforms
13.
J Biol Chem ; 289(9): 6120-32, 2014 Feb 28.
Article in English | MEDLINE | ID: mdl-24415756

ABSTRACT

Phosphatidylinositol 4-kinase type IIIα (PI4KA) is a host factor essential for hepatitis C virus replication and hence is a target for drug development. PI4KA has also been linked to endoplasmic reticulum exit sites and generation of plasma membrane phosphoinositides. Here, we developed highly specific and potent inhibitors of PI4KA and conditional knock-out mice to study the importance of this enzyme in vitro and in vivo. Our studies showed that PI4KA is essential for the maintenance of plasma membrane phosphatidylinositol 4,5-bisphosphate pools but only during strong stimulation of receptors coupled to phospholipase C activation. Pharmacological blockade of PI4KA in adult animals leads to sudden death closely correlating with the drug's ability to induce phosphatidylinositol 4,5-bisphosphate depletion after agonist stimulation. Genetic inactivation of PI4KA also leads to death; however, the cause in this case is due to severe intestinal necrosis. These studies highlight the risks of targeting PI4KA as an anti-hepatitis C virus strategy and also point to important distinctions between genetic and pharmacological studies when selecting host factors as putative therapeutic targets.


Subject(s)
Cell Membrane/enzymology , Phosphatidylinositol 4,5-Diphosphate/metabolism , Phosphatidylinositol Phosphates/metabolism , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Animals , COS Cells , Cell Membrane/genetics , Chlorocebus aethiops , Enzyme Activation/genetics , Gene Targeting , HEK293 Cells , Hepatitis C/enzymology , Hepatitis C/genetics , Hepatitis C/therapy , Humans , Mice , Mice, Transgenic , Minor Histocompatibility Antigens , Phosphatidylinositol 4,5-Diphosphate/genetics , Phosphatidylinositol Phosphates/genetics , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Phosphotransferases (Alcohol Group Acceptor)/genetics , Type C Phospholipases/genetics , Type C Phospholipases/metabolism
14.
Am J Physiol Endocrinol Metab ; 302(7): E807-16, 2012 Apr 01.
Article in English | MEDLINE | ID: mdl-22275755

ABSTRACT

TRPM2 Ca(2+)-permeable cation channel is widely expressed and activated by markers of cellular stress. Since inflammation and stress play a major role in insulin resistance, we examined the role of TRPM2 Ca(2+) channel in glucose metabolism. A 2-h hyperinsulinemic euglycemic clamp was performed in TRPM2-deficient (KO) and wild-type mice to assess insulin sensitivity. To examine the effects of diet-induced obesity, mice were fed a high-fat diet for 4-10 mo, and metabolic cage and clamp studies were conducted in conscious mice. TRPM2-KO mice were more insulin sensitive partly because of increased glucose metabolism in peripheral organs. After 4 mo of high-fat feeding, TRPM2-KO mice were resistant to diet-induced obesity, and this was associated with increased energy expenditure and elevated expressions of PGC-1α, PGC-1ß, PPARα, ERRα, TFAM, and MCAD in white adipose tissue. Hyperinsulinemic euglycemic clamps showed that TRPM2-KO mice were more insulin sensitive, with increased Akt and GSK-3ß phosphorylation in heart. Obesity-mediated inflammation in adipose tissue and liver was attenuated in TRPM2-KO mice. Overall, TRPM2 deletion protected mice from developing diet-induced obesity and insulin resistance. Our findings identify a novel role of TRPM2 Ca(2+) channel in the regulation of energy expenditure, inflammation, and insulin resistance.


Subject(s)
Energy Metabolism/physiology , Glucose/metabolism , TRPM Cation Channels/physiology , Animals , Blotting, Western , Body Composition/physiology , Body Weight/physiology , Calmodulin/metabolism , Calorimetry, Indirect , Dietary Fats/pharmacology , Glucose Clamp Technique , Glucose Tolerance Test , Immunoprecipitation , Inflammation/metabolism , Insulin Receptor Substrate Proteins/metabolism , Insulin Resistance/physiology , Mice , Mice, Knockout , Myocardium/enzymology , Myocardium/metabolism , Oxygen Consumption/physiology , Phosphorylation , RNA/biosynthesis , RNA/genetics , Superoxide Dismutase/metabolism
15.
J Neurosci Res ; 89(11): 1723-36, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21826702

ABSTRACT

The mammalian nicotinamide-adenine dinucleotide (NAD)-dependent deacetylase Sirt1 impacts different processes involved in the maintenance of brain integrity and in the pathogenic pathways associated with several neurodegenerative disorders, including Alzheimer's disease. Here we used human Sirt1 transgenic mice to demonstrate that neuron-specific Sirt1 overexpression promoted neurite outgrowth and improved cell viability under normal and nutrient-limiting conditions in primary culture systems and that Sirt1-overexpressing neurons exhibited higher tolerance to cell death or degeneration induced by amyloid-ß1-42 oligomers. Coincidentally, we found that enhanced Sirt1 expression in neurons downregulated the mammalian target of rapamycin (mTOR) protein levels and its phosphorylation without changes in its mRNA levels, which was accompanied by concomitant inhibition of the mTOR downstream signaling activity as revealed by decreased p70S6 kinase (p70S6K) phosphorylation at Thr389. Consistently with this, using a Sirt1 siRNA transfection approach, we observed that reduction of endogenous mouse Sirt1 led to increased levels of mTOR and phosphorylation of itself and p70S6K as well as impaired cell survival and neurite outgrowth in wild-type mouse primary neurons, corroborating a suppressing effect of mTOR by Sirt1. Correspondingly, the mTOR inhibitor rapamycin markedly improved neuronal cell survival in response to nutrient deprivation and significantly enhanced neurite outgrowth in wild-type mouse neurons. The protective effect of rapamycin was extended to neurons even with Sirt1 siRNA knockdown that displayed developmental abnormalities compared with siRNA control-treated cells. Collectively, our findings suggest that Sirt1 may act to promote growth and survival of neurons in the central nervous system via its negative modulation of mTOR signaling.


Subject(s)
Cell Survival/physiology , Neurites/metabolism , Neurons/metabolism , Signal Transduction/physiology , Sirtuin 1/metabolism , TOR Serine-Threonine Kinases/metabolism , Animals , Cells, Cultured , Mice , Mice, Transgenic , Sirtuin 1/genetics
16.
Proc Natl Acad Sci U S A ; 108(28): 11578-83, 2011 Jul 12.
Article in English | MEDLINE | ID: mdl-21709234

ABSTRACT

The generation of reactive oxygen species (ROS) is inherent to immune responses. ROS are crucially involved in host defense against pathogens by promoting bacterial killing, but also as signaling agents coordinating the production of cytokines. Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca(2+)-permeable channel gated via binding of ADP-ribose, a metabolite formed under conditions of cellular exposure to ROS. Here, we show that TRPM2-deficient mice are extremely susceptible to infection with Listeria monocytogenes (Lm), exhibiting an inefficient innate immune response. In a comparison with IFNγR-deficient mice, TRPM2(-/-) mice shared similar features of uncontrolled bacterial replication and reduced levels of inducible (i)NOS-expressing monocytes, but had intact IFNγ responsiveness. In contrast, we found that levels of cytokines IL-12 and IFNγ were diminished in TRPM2(-/-) mice following Lm infection, which correlated with their reduced innate activation. Moreover, TRPM2(-/-) mice displayed a higher degree of susceptibility than IL-12-unresponsive mice, and supplementation with recombinant IFNγ was sufficient to reverse the unrestrained bacterial growth and ultimately the lethal phenotype of Lm-infected TRPM2(-/-) mice. The severity of listeriosis we observed in TRPM2(-/-) mice has not been reported for any other ion channel. These findings establish an unsuspected role for ADP-ribose and ROS-mediated cation flux for innate immunity, opening up unique possibilities for immunomodulatory intervention through TRPM2.


Subject(s)
Immunity, Innate/physiology , Listeria monocytogenes/immunology , TRPM Cation Channels/immunology , Adjuvants, Immunologic/pharmacology , Animals , Cytokines/biosynthesis , Female , Immunity, Innate/drug effects , Immunity, Innate/genetics , Interferon-gamma/pharmacology , Interleukin-12/deficiency , Interleukin-12/genetics , Interleukin-12/immunology , Interleukin-12 Receptor beta 2 Subunit/deficiency , Interleukin-12 Receptor beta 2 Subunit/genetics , Interleukin-12 Receptor beta 2 Subunit/immunology , Listeria monocytogenes/pathogenicity , Listeriosis/immunology , Listeriosis/prevention & control , Macrophages/immunology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neutrophils/immunology , Receptors, Interferon/deficiency , Receptors, Interferon/genetics , Receptors, Interferon/immunology , Recombinant Proteins , TRPM Cation Channels/deficiency , TRPM Cation Channels/genetics , Interferon gamma Receptor
17.
J Neurosci Methods ; 193(2): 254-63, 2010 Nov 30.
Article in English | MEDLINE | ID: mdl-20832426

ABSTRACT

To properly understand the function of genes of neurological interest, in vivo manipulation in the adult is essential, particularly when the target gene is involved in brain development. Moreover, since the physiological effects of target protein may be region-specific, targeting a distinct brain region could be required to dissect these effects in specific brain locations. Infection of somatic tissues of transgenic mice bearing loxP-flanked gene sequences with a viral vector expressing Cre recombinase provides a means of allowing flexible spatio-temporal control of target gene expression. Viral vector-mediated Cre expression could be used to mediate localized gene modulation in a specific brain region. In the present study this technology was applied to the glycine transporter type-1 (GlyT1) protein which is responsible for the uptake of synaptic glycine in the forebrain and has been implicated as a therapeutic target for the treatment of schizophrenia. Since GlyT1 is widely expressed in glial cells, we employed an adenoviral-based vector (Ad5) to deliver Cre protein, due to the preferentially transduction of glial cells by adenoviral vectors in rodent brain. We show significant reduced GlyT1 binding specifically in the thalamic area of conditional GlyT1 (GlyT1c) transgenic mice injected with Ad5-Cre virus, as measured by GlyT1 autoradiography. In conclusion, we demonstrated the validity of viral vector-mediated delivery of Cre to loxP targeted transgenic mice as a novel strategy to investigate target gene function in selected subregions of the adult brain, which provides a valuable technique to investigate gene function both in normal physiology and in disease models.


Subject(s)
Adenoviridae/physiology , Glycine Plasma Membrane Transport Proteins/metabolism , Thalamus/metabolism , Analysis of Variance , Animals , Animals, Newborn , Autoradiography/methods , Cells, Cultured , Extracellular Matrix Proteins/metabolism , Ganglia, Spinal/cytology , Genetic Vectors/physiology , Glycine Plasma Membrane Transport Proteins/deficiency , Integrases/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neuroglia/metabolism , Neurons/metabolism , Protein Binding/physiology , Protein-Lysine 6-Oxidase/metabolism , Proteins/genetics , RNA, Untranslated , Thalamus/cytology , beta-Galactosidase/metabolism
18.
Am J Physiol Gastrointest Liver Physiol ; 296(4): G923-30, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19164486

ABSTRACT

P2Y receptors have been reported to modulate gastrointestinal functions. The newest family member is the nucleotide-sugar receptor P2Y14. P2ry14 mRNA was detected throughout the rat gut, with the highest level being in the forestomach. We investigated the role of the receptor in stomach motility using cognate agonists and knockout (KO) mice. In rat isolated forestomach, 100 microM UDP-glucose and 100 muM UDP-galactose both increased the baseline muscle tension (BMT) by 6.2+/-0.6 and 1.6+/-0.6 mN (P<0.05, n=3-4), respectively, and the amplitude of contractions during electrical field stimulation (EFS) by 3.7+/-1.7 and 4.3+/-2.5 mN (P<0.05, n=3-4), respectively. In forestomach from wild-type (WT) mice, 100 microM UDP-glucose increased the BMT by 1.0+/-0.1 mN (P<0.05, n=6) but this effect was lost in the KO mice (change of -0.1+/-0.1 mN, n=6). The 100 microM UDP-glucose also increased the contraction amplitude during EFS in this tissue from the WT animals (0.9+/-0.4 mN, P < 0.05, n=6) but not from the KO mice (0.0+/-0.2 mN, n=6). In vivo, UDP-glucose at 2,000 mg/kg ip reduced gastric emptying in rats by 49.7% (P<0.05, n=4-6) and in WT and KO mice by 56.1 and 66.2%, respectively (P<0.05, n=7-10) vs. saline-treated control animals. There was no significant difference in gastric emptying between WT and KO animals receiving either saline or d-glucose. These results demonstrate a novel function of the P2Y14 receptor associated with contractility in the rodent stomach that does not lead to altered gastric emptying after receptor deletion and an ability of UDP-glucose to delay gastric emptying without involving the P2Y14 receptor.


Subject(s)
Gastric Emptying/drug effects , Receptors, Purinergic P2/metabolism , Uridine Diphosphate Glucose/pharmacology , Animals , Dose-Response Relationship, Drug , Gene Expression Regulation/physiology , Lac Operon/genetics , Lac Operon/physiology , Mice , Mice, Knockout , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Receptors, Purinergic P2/genetics , Receptors, Purinergic P2Y , Uridine Diphosphate Galactose/pharmacology
19.
Pain ; 139(1): 225-236, 2008 Sep 30.
Article in English | MEDLINE | ID: mdl-18502582

ABSTRACT

It has been postulated that the G protein-coupled receptor, GPR55, is a third cannabinoid receptor. Given that the ligands at the CB(1) and CB(2) receptors are effective analgesic and anti-inflammatory agents, the role of GPR55 in hyperalgesia associated with inflammatory and neuropathic pain has been investigated. As there are no well-validated GPR55 tool compounds, a GPR55 knockout (GPR55(-/-)) mouse line was generated and fully backcrossed onto the C57BL/6 strain. General phenotypic analysis of GPR55(-/-) mice revealed no obvious primary differences, compared with wild-type (GPR55(+/+)) littermates. GPR55(-/-) mice were then tested in the models of adjuvant-induced inflammation and partial nerve ligation. Following intraplantar administration of Freund's complete adjuvant (FCA), inflammatory mechanical hyperalgesia was completely absent in GPR55(-/-) mice up to 14 days post-injection. Cytokine profiling experiments showed that at 14 days post-FCA injection there were increased levels of IL-4, IL-10, IFN gamma and GM-CSF in paws from the FCA-injected GPR55(-/-) mice when compared with the FCA-injected GPR55(+/+) mice. This suggests that GPR55 signalling can influence the regulation of certain cytokines and this may contribute to the lack of inflammatory mechanical hyperalgesia in the GPR55(-/-) mice. In the model of neuropathic hypersensitivity, GPR55(-/-) mice also failed to develop mechanical hyperalgesia up to 28 days post-ligation. These data clearly suggest that the manipulation of GPR55 may have therapeutic potential in the treatment of both inflammatory and neuropathic pain.


Subject(s)
Hyperalgesia/metabolism , Inflammation Mediators/physiology , Neuralgia/metabolism , Receptors, Cannabinoid/physiology , Amino Acid Sequence , Animals , Base Sequence , Female , Hyperalgesia/genetics , Inflammation/genetics , Inflammation/metabolism , Inflammation/physiopathology , Inflammation Mediators/metabolism , Ligation , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Molecular Sequence Data , Neuralgia/genetics , Pain Measurement/methods , Physical Stimulation/methods , Receptors, Cannabinoid/deficiency , Receptors, Cannabinoid/genetics
20.
BMC Dev Biol ; 5: 28, 2005 Dec 28.
Article in English | MEDLINE | ID: mdl-16381610

ABSTRACT

BACKGROUND: Studies of gene function in the mouse have relied mainly on gene targeting via homologous recombination. However, this approach is difficult to apply in specific windows of time, and to simultaneously knock-down multiple genes. Here we report an efficient method for dsRNA-mediated gene silencing in late cleavage-stage mouse embryos that permits examination of phenotypes at post-implantation stages. RESULTS: We show that introduction of Bmp4 dsRNA into intact blastocysts by electroporation recapitulates the genetic Bmp4 null phenotype at gastrulation. It also reveals a novel role for Bmp4 in the regulation the anterior visceral endoderm specific gene expression and its positioning. We also show that RNAi can be used to simultaneously target several genes. When applied to the three murine isoforms of Dishevelled, it leads to earlier defects than previously observed in double knock-outs. These include severe delays in post-implantation development and defects in the anterior midline and neural folds at headfold stages. CONCLUSION: Our results indicate that the BMP4 signalling pathway contributes to the development of the anterior visceral endoderm, and reveal an early functional redundancy between the products of the murine Dishevelled genes. The proposed approach constitutes a powerful tool to screen the functions of genes that govern the development of the mouse embryo.


Subject(s)
Embryo Implantation/physiology , Embryonic Development , RNA, Small Interfering/pharmacology , Signal Transduction/physiology , Adaptor Proteins, Signal Transducing , Animals , Blastocyst , Bone Morphogenetic Protein 4 , Bone Morphogenetic Proteins/genetics , Bone Morphogenetic Proteins/physiology , Dishevelled Proteins , Electroporation , Endoderm , Gene Silencing , Methods , Mice , Phenotype , Phosphoproteins/genetics , Phosphoproteins/physiology
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