Background and purpose:
Rimonabant (Acomplia
TM
, SR141716A), a cannabinoid CB
1
receptor inverse agonist, has recently been approved for the treatment of obesity. There are, however, concerns ...regarding its side effect profile. Developing a CB
1
antagonist with a different pharmacological mechanism may lead to a safer alternative. To this end we have screened a proprietary small molecule library and have discovered a novel class of allosteric antagonist at CB
1
receptors. Herein, we have characterized an optimized prototypical molecule, PSNCBAM‐1, and its hypophagic effects
in vivo
.
Experimental approach:
A CB
1
yeast reporter assay was used as a primary screen. PSNCBAM‐1 was additionally characterized in
35
S‐GTPγS, cAMP and radioligand binding assays. An acute rat feeding model was used to evaluate its effects on food intake and body weight
in vivo
.
Key results:
In CB
1
receptor yeast reporter assays, PSNCBAM‐1 blocked the effects induced by agonists such as CP55,940, WIN55212‐2, anandamide (AEA) or 2‐arachidonoyl glycerol (2‐AG). The antagonist characteristics of PSNCBAM‐1 were confirmed in
35
S‐GTPγS binding and cAMP assays and was shown to be non‐competitive by Schild analyses. PSNCBAM‐1 did not affect CB
2
receptors. In radioligand binding assays, PSNCBAM‐1 increased the binding of
3
HCP55,940 despite its antagonist effects. In an acute rat feeding model, PSNCBAM‐1 decreased food intake and body weight.
Conclusions and implications:
PSNCBAM‐1 exerted its effects through selective allosteric modulation of the CB
1
receptor. The acute effects on food intake and body weight induced in rats provide a first report of
in vivo
activity for an allosteric CB
1
receptor antagonist.
British Journal of Pharmacology
(2007)
152
, 805–814; doi:
10.1038/sj.bjp.0707347
; published online 25 June 2007
Background and purpose:
Rimonabant (AcompliaTM, SR141716A), a cannabinoid CB1 receptor inverse agonist, has recently been approved for the treatment of obesity. There are, however, concerns regarding ...its side effect profile. Developing a CB1 antagonist with a different pharmacological mechanism may lead to a safer alternative. To this end we have screened a proprietary small molecule library and have discovered a novel class of allosteric antagonist at CB1 receptors. Herein, we have characterized an optimized prototypical molecule, PSNCBAM‐1, and its hypophagic effects in vivo.
Experimental approach:
A CB1 yeast reporter assay was used as a primary screen. PSNCBAM‐1 was additionally characterized in 35S‐GTPγS, cAMP and radioligand binding assays. An acute rat feeding model was used to evaluate its effects on food intake and body weight in vivo.
Key results:
In CB1 receptor yeast reporter assays, PSNCBAM‐1 blocked the effects induced by agonists such as CP55,940, WIN55212‐2, anandamide (AEA) or 2‐arachidonoyl glycerol (2‐AG). The antagonist characteristics of PSNCBAM‐1 were confirmed in 35S‐GTPγS binding and cAMP assays and was shown to be non‐competitive by Schild analyses. PSNCBAM‐1 did not affect CB2 receptors. In radioligand binding assays, PSNCBAM‐1 increased the binding of 3HCP55,940 despite its antagonist effects. In an acute rat feeding model, PSNCBAM‐1 decreased food intake and body weight.
Conclusions and implications:
PSNCBAM‐1 exerted its effects through selective allosteric modulation of the CB1 receptor. The acute effects on food intake and body weight induced in rats provide a first report of in vivo activity for an allosteric CB1 receptor antagonist.
British Journal of Pharmacology (2007) 152, 805–814; doi:10.1038/sj.bjp.0707347; published online 25 June 2007
Methanol oxidation is one of the most important processes in a direct methanol fuel cell (DMFC). Proper anodic catalysis ensures high energy conversion and operation cost of the fuel cell. Although a ...proton exchange membrane is a successful electrolyte of DMFC, its drawbacks or limitations can be avoided by replacing the solid membrane with a liquid electrolyte that is not subject to evaporation, especially at elevated temperatures. A promising candidate for such electrolyte is an ionic liquid. The performance of the anode catalyst will be affected when the electrolyte has been changed. In our paper, we report a fast Box–Behnken design to identify the most critical factors that would determine the performance of a specific catalyst—platinum-coated gold nanoporous film (PGNF). Our research revealed that the catalytic kinetics is the critical factor for PGNF in aqueous solution electrolyte; while catalyst poisoning was the most critical when the ionic liquid BMImBF
4
was the electrolyte. This example of how statistic tools could be used in the development of fuel cells could be expanded to the studies of other systems.
Graphical abstract
Background and purpose: Rimonabant (Acomplia, SR1 41716A), a cannabinoid CB sub(1) receptor inverse agonist, has recently been approved for the treatment of obesity. There are, however, concerns ...regarding its side effect profile. Developing a CB sub(1) antagonist with a different pharmacological mechanism may lead to a safer alternative. To this end we have screened a proprietary small molecule library and have discovered a novel class of allosteric antagonist at CB sub(1) receptors. Herein, we have characterized an optimized prototypical molecule, PSNCBAM-1, and its hypophagic effects in vivo. Experimental approach: A CB sub(1) yeast reporter assay was used as a primary screen. PSNCBAM-1 was additionally characterized in super(35)S-GTP gamma S, cAMP and radioligand binding assays. An acute rat feeding model was used to evaluate its effects on food intake and body weight in vivo. Key results: In CB sub(1) receptor yeast reporter assays, PSNCBAM-1 blocked the effects induced by agonists such as CP55,940, WIN55212-2, anandamide (AEA) or 2-arachidonoyl glycerol (2-AG). The antagonist characteristics of PSNCBAM-1 were confirmed in super(35)S-GTP gamma S binding and cAMP assays and was shown to be non-competitive by Schild analyses. PSNCBAM-1 did not affect CB sub(2) receptors. In radioligand binding assays, PSNCBAM-1 increased the binding of super(3)HCP55,940 despite its antagonist effects. In an acute rat feeding model, PSNCBAM-1 decreased food intake and body weight. Conclusions and implications: PSNCBAM-1 exerted its effects through selective allosteric modulation of the CB sub(1) receptor. The acute effects on food intake and body weight induced in rats provide a first report of in vivo activity for an allosteric CB sub(1) receptor antagonist.
Objective To assess consumption of foods from food packages provided by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) among 80 Chinese prenatal WIC recipients ...living in Oakland or San Francisco, Calif.
Design During a single interview, a food frequency questionnaire was used to assess WIC food consumption by the prenatal patients for the period before and after receipt of WIC vouchers.
Setting The study was conducted at Asian Health Services, Oakland, and the Chinatown Public Health Center of the San Francisco Department of Public Health in California.
Subjects Eighty low-income Chinese prenatal women with limited education and limited ability to speak English, aged 21 to 43 years, with gestational stages of 15 to 38 weeks.
Statistical analyses performed Descriptive statistics (frequency and percent distribution) were used to report the findings of the study.
Results Subjects reported that before receiving WIC vouchers, milk, eggs, and juice were the only foods in their WIC food package that had been consumed frequently (>5 times/week) in their daily diet. Other WIC foods, including cheese, peanut butter, dried beans, and hot and cold cereals, were consumed infrequently (0 to 1 time/month). Subjects reported that with the availability of WIC vouchers, milk, eggs, and juice remained frequently consumed with 81% to 100% of monthly supply as the most prevalent reported consumption rate. Dried beans and hot and cold cereals were also consumed frequently. Cheese remained poorly consumed (0% to 20% of the monthly supply). As many as 74 of 80 subjects stated that they had shared foods from their own WIC package, except milk, with their families. The use of any WIC foods provided to other children in the family was not assessed in this study.
Applications Data from this study indicate that most WIC foods were well used by Chinese prenatal patients. The most notable exception was cheese, which was poorly consumed. The ready consumption of milk by pregnant Chinese WIC recipients in this study suggests that milk may be readily consumed by these women, even though it is atypical of the Asian diet. The WIC food package for Chinese prenatal patients may be improved by omitting cheese and substituting more milk and/or foods such as tofu and dark green leafy vegetables.
J Am Diet Assoc. 1999;99:1549–1553.
Staphylococcus aureus is a potent biofilm former on host tissue and medical implants, and biofilm growth is a critical virulence determinant for chronic infections. Recent studies suggest that many ...clinical isolates form polysaccharide-independent biofilms. However, a systematic screen for defective mutants has not been performed to identify factors important for biofilm formation in these strains. We created a library of 14,880 mariner transposon mutants in a S. aureus strain that generates a proteinaceous and extracellular DNA based biofilm matrix. The library was screened for biofilm defects and 31 transposon mutants conferred a reproducible phenotype. In the pool, 16 mutants overproduced extracellular proteases and the protease inhibitor alpha(2)-macroglobulin restored biofilm capacity to 13 of these mutants. The other 15 mutants in the pool displayed normal protease levels and had defects in genes involved in autolysis, osmoregulation, or uncharacterized membrane proteins. Two transposon mutants of interest in the GraRS two-component system and a putative inositol monophosphatase were confirmed in a flow cell biofilm model, genetically complemented, and further verified in a community-associated methicillin-resistant S. aureus (CA-MRSA) isolate. Collectively, our screen for biofilm defective mutants identified novel loci involved in S. aureus biofilm formation and underscored the importance of extracellular protease activity and autolysis in biofilm development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Periprosthetic joint infections (PJIs) are a devastating complication that occurs in 2% of patients following joint replacement. These infections are costly and difficult to treat, often requiring ...multiple corrective surgeries and prolonged antimicrobial treatments. The Gram-positive bacterium Staphylococcus aureus is one of the most common causes of PJIs, and it is often resistant to a number of commonly used antimicrobials. This tolerance can be partially attributed to the ability of S. aureus to form biofilms. Biofilms associated with the surface of indwelling medical devices have been observed on components removed during chronic infection, however, the development and localization of biofilms during PJIs remains unclear. Prior studies have demonstrated that synovial fluid, in the joint cavity, promotes the development of bacterial aggregates with many biofilm-like properties, including antibiotic resistance. We anticipate these aggregates have an important role in biofilm formation and antibiotic tolerance during PJIs. Therefore, we sought to determine specifically how synovial fluid promotes aggregate formation and the impact of this process on surface attachment. Using flow cytometry and microscopy, we quantified the aggregation of various clinical S. aureus strains following exposure to purified synovial fluid components. We determined that fibrinogen and fibronectin promoted bacterial aggregation, while cell free DNA, serum albumin, and hyaluronic acid had minimal effect. To determine how synovial fluid mediated aggregation affects surface attachment, we utilized microscopy to measure bacterial attachment. Surprisingly, we found that synovial fluid significantly impeded bacterial surface attachment to a variety of materials. We conclude from this study that fibrinogen and fibronectin in synovial fluid have a crucial role in promoting bacterial aggregation and inhibiting surface adhesion during PJI. Collectively, we propose that synovial fluid may have conflicting protective roles for the host by preventing adhesion to surfaces, but by promoting bacterial aggregation is also contributing to the development of antibiotic tolerance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus are part of the natural flora of humans and other mammals. We found that spent media from the CoNS species Staphylococcus caprae can ...inhibit agr-mediated quorum sensing by all classes of S. aureus. A biochemical assessment of the inhibitory activity suggested that the S. caprae autoinducing peptide (AIP) was responsible, and mass spectrometric analysis identified the S. caprae AIP as an eight-residue peptide (YSTCSYYF). Using a murine model of intradermal MRSA infection, the therapeutic efficacy of synthetic S. caprae AIP was evident by a dramatic reduction in both dermonecrotic injury and cutaneous bacterial burden relative to controls. Competition experiments between S. caprae and MRSA demonstrated a significant reduction in MRSA burden using murine models of both skin colonization and intradermal infection. Our findings indicate that important interactions occur between commensals that can impact disease outcomes and potentially shape the composition of the natural flora.
Display omitted
•Staphylococcus caprae autoinducer (AIP) inhibits agr quorum sensing in S. aureus•Mass spectrometry identified the S. caprae AIP as an eight-residue thiolactone peptide•S. caprae AIP attenuates MRSA-induced necrosis and burden in a skin infection model•S. caprae directly competes with MRSA during skin colonization and infection
Paharik, Parlet, et al. demonstrate that the human commensal Staphylococcus caprae competes with Staphylococcus aureus by inhibiting quorum sensing. Through signal interference, S. caprae reduces methicillin-resistant S. aureus burden in both skin colonization and infection, highlighting the benefits of healthy skin flora and suggesting a new avenue for probiotic therapy.
Cystic fibrosis (CF) is a life-shortening disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Although bacterial lung infection and the resulting ...inflammation cause most of the morbidity and mortality, how the loss of CFTR function first disrupts airway host defence has remained uncertain. To investigate the abnormalities that impair elimination when a bacterium lands on the pristine surface of a newborn CF airway, we interrogated the viability of individual bacteria immobilized on solid grids and placed onto the airway surface. As a model, we studied CF pigs, which spontaneously develop hallmark features of CF lung disease. At birth, their lungs lack infection and inflammation, but have a reduced ability to eradicate bacteria. Here we show that in newborn wild-type pigs, the thin layer of airway surface liquid (ASL) rapidly kills bacteria in vivo, when removed from the lung and in primary epithelial cultures. Lack of CFTR reduces bacterial killing. We found that the ASL pH was more acidic in CF pigs, and reducing pH inhibited the antimicrobial activity of ASL. Reducing ASL pH diminished bacterial killing in wild-type pigs, and, conversely, increasing ASL pH rescued killing in CF pigs. These results directly link the initial host defence defect to the loss of CFTR, an anion channel that facilitates HCO(3)(-) transport. Without CFTR, airway epithelial HCO(3)(-) secretion is defective, the ASL pH falls and inhibits antimicrobial function, and thereby impairs the killing of bacteria that enter the newborn lung. These findings suggest that increasing ASL pH might prevent the initial infection in patients with CF, and that assaying bacterial killing could report on the benefit of therapeutic interventions.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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