We investigated the contribution of corticotropin-releasing factor (CRF) receptors types 1 and 2 (CRF1 and CRF2) in mediating the ACTH response to shock, alcohol injection, or endotoxemia in the rat. ...Peptidic (Astressin B and Astressin2-B) and nonpeptidic (NBI 30775) CRF antagonists were injected iv before the stressors at doses previously shown to be effective in blocking the corresponding receptors. Because NBI 30775, which specifically blocks CRF1, penetrates the brain following systemic injection, we also compared its effect with that of Astressin B, which primarily, though not exclusively, targets CRF1 but does not cross the blood-brain barrier. Shocks, alcohol (4.5 g/kg, intragastrically) or lipopolysaccharide (LPS, 1 μg/kg, iv) all significantly released ACTH. Astressin B or NBI 30775 markedly decreased the effect of shocks or alcohol and also interfered, though less significantly so, with the influence of LPS. In contrast, specific blockade of CRF2 with Astressin2-B, although not significantly altering the overall ACTH response to shocks, alcohol, or LPS, slightly enhanced ACTH levels during the early phase of some of these responses. Interestingly, combined administration of NBI 30775 and Astressin2-B decreased ACTH levels more than NBI 30775 alone, although this difference did not reach statistical significance. Finally, blockade of CRF1 and/or CRF2 augmented LPS- induced TNF-α and IL-6 release. Collectively, there results confirm the critical role played by CRF1 in mediating the ACTH response to shocks, alcohol and LPS, whereas the influence of CRF2 remains subtle. Finally, we showed that peripheral endogenous CRF restrains the ability of LPS to release cytokines.
In contrast to GC–MS, many factors are influencing mass spectra of organic compounds when analyzed by LC–MS. In-source or transport collision-induced dissociation by electrospray ionization or ...atmospheric pressure chemical ionization demonstrate the need for experimental condition standardization when building-up a library of reference spectra. Magnetic sector, quadrupole, ion trap or time-of-flight filters placed on single or multiple mass spectrometry instruments coupled with HPLC deliver unique mass intensities pattern from the same molecules that are most often not readily comparable between each other. This makes it very difficult or even impossible to rely on any collections of reference data whatever comparison algorithm is applied for library search or manual comparison when full confirmation of identity is required. Typical areas of expertise are very sensitive to sound and complete package procedures to withstand administrative or court’s scrutiny. In this paper, this problem is referred to the specific field of forensic toxicology and doping control in sports. Several official guidelines have been released recently and await confrontation with concrete cases. Closely related areas like residues in living animals and meat products are regulating these aspects with detailed procedures. Basically, they all propose the accumulation of a finite quantity of information about the unknown molecule and the reference substance. These confirmatory packages are briefly exposed, compared and evaluated for their future application to the newest LC–MS techniques that are more frequently used within these critical fields of expertise.
A 'binge' is defined by National Institute on Alcohol Abuse and Alcoholism as an excessive pattern of alcohol drinking that produces blood-alcohol levels (BALs) greater than 0.08 g% within a 2-h ...period and may or may not be associated with dependence. The purpose of this investigation was to explore the effects of several neuropharmacological agents in an animal model in which outbred rats voluntarily and orally self-administer pharmacologically meaningful alcohol doses that produce BALs >or=0.08 g% in daily limited access two-bottle choice and operant drinking sessions. Rats were trained to self-administer either 10% (w/v) alcohol solution sweetened with 'supersac' (3% glucose+0.125% saccharin) or supersac alone versus water in a two-bottle choice or operant situation during 30-min daily sessions. Rats were then injected systemically with multiple doses of duloxetine, naltrexone, and the corticotropin-releasing factor antagonist, MPZP, in Latin-square designs. Alcohol binge drinkers reliably consumed amounts of alcohol sufficient to produce BALs >or=0.08 g%. Duloxetine dose-dependently suppressed two-bottle choice alcohol binge drinking and operant alcohol responding as well as operant supersac responding, but did not affect two-bottle choice supersac drinking. Naltrexone-suppressed alcohol binge drinking at very low doses and suppressed supersac drinking at moderate-to-high doses. MPZP did not affect alcohol or supersac consumption. Different profiles for drugs that suppress binge-like alcohol drinking compared with dependence-induced drinking provide a heuristic foundation for future medications development.
Our ability to predict future climate change relies on our understanding of current and future CO2 fluxes, particularly on a regional scale (100-1000 km). CO2 regional sources and sinks are still ...poorly understood. Inverse transport modeling, a method often used to quantify these fluxes, relies on atmospheric CO2 measurements. One of the main challenges for the transport models used in the inversions is to properly reproduce CO2 vertical gradients between the boundary layer and the free troposphere, as these gradients impact on the partitioning of the calculated fluxes between the different model regions. Vertical CO2 profiles are very well suited to assess the performances of the models. In this paper, we conduct a comparison between observed and modeled CO2 profiles recorded during two CAATER campaigns that occurred in May 2001 and October 2002 over Western Europe, as described in a companion paper. We test different combinations between a global transport model (LMDZt), a mesoscale transport model (CHIMERE), and different sets of biospheric fluxes, all chosen with a diurnal cycle (CASA, SiB2 and ORCHIDEE). The vertical profile comparison shows that: 1) in most cases the influence of the biospheric flux is small but sometimes not negligible, ORCHIDEE giving the best results in the present study; 2) LMDZt is most of the time too diffuse, as it simulates a too high boundary layer height; 3) CHIMERE better reproduces the observed gradients between the boundary layer and the free troposphere, but is sometimes too variable and gives rise to incoherent structures. We conclude there is a need for more vertical profiles to conduct further studies to improve the parameterization of vertical transport in the models used for CO2 flux inversions. Furthermore, we use a modeling method to quantify CO2 fluxes at the regional scale from a chosen observing point, coupling influence functions from the transport model LMDZt (that works quite well at the synoptic scale) with information on the space-time distribution of fluxes. This modeling method is compared to a dual tracer method (the so-called Radon method) for a case study on 25 May 2001 during which simultaneous well-correlated in situ CO2 and Radon 222 measurements have been collected. Both methods give a similar result: a flux within the Radon 222 method uncertainty (35%), that is an atmospheric CO2 sink of -4.2 to -4.4 gC m-2 day-1 . We have estimated the uncertainty of the modeling method to be at least 33% on average, and even more for specific individual events. This method allows the determination of the area that contributed to the CO2 observed concentration. In our case, the observation point located at 1700 m a.s.l. in the north of France, is influenced by an area of 1500×700 km2 that covers the Benelux region, part of Germany and western Poland. Furthermore, this method allows deconvolution between the different contributing fluxes. In this case study, the biospheric sink contributes 73% of the total flux, fossil fuel emissions for 27%, the oceanic flux being negligible. However, the uncertainties of the influence function method need to be better assessed. This could be possible by applying it to other cases where the calculated fluxes can be checked independently, for example at tall towers where simultaneous CO2 and Radon 222 measurements can be conducted. The use of optimized fluxes (from atmospheric inversions) and of mesoscale models for atmospheric transport may also significantly reduce the uncertainties.
The ability to reliably estimate CO2 fluxes from current in situ atmospheric CO2 measurements and future satellite CO2 measurements is dependent on transport model performance at synoptic and shorter ...timescales. The TransCom continuous experiment was designed to evaluate the performance of forward transport model simulations at hourly, daily, and synoptic timescales, and we focus on the latter two in this paper. Twenty‐five transport models or model variants submitted hourly time series of nine predetermined tracers (seven for CO2) at 280 locations. We extracted synoptic‐scale variability from daily averaged CO2 time series using a digital filter and analyzed the results by comparing them to atmospheric measurements at 35 locations. The correlations between modeled and observed synoptic CO2 variabilities were almost always largest with zero time lag and statistically significant for most models and most locations. Generally, the model results using diurnally varying land fluxes were closer to the observations compared to those obtained using monthly mean or daily average fluxes, and winter was often better simulated than summer. Model results at higher spatial resolution compared better with observations, mostly because these models were able to sample closer to the measurement site location. The amplitude and correlation of model‐data variability is strongly model and season dependent. Overall similarity in modeled synoptic CO2 variability suggests that the first‐order transport mechanisms are fairly well parameterized in the models, and no clear distinction was found between the meteorological analyses in capturing the synoptic‐scale dynamics.
The distribution of the fossil fuel component in atmospheric CO2 cannot be measured directly at a cheap cost. Could anthropogenic tracers with source patterns similar to fossil fuel CO2 then be used ...for that purpose? Here we present and evaluate a methodology using surrogate tracers, CO, SF6, and C2Cl4, to deduce fossil fuel CO2. A three‐dimensional atmospheric chemistry transport model is used to simulate the relationship between each tracer and fossil fuel CO2. In summertime the regression slopes between fossil fuel CO2 and surrogate tracers show large spatial variations for chemically active tracers (CO and C2Cl4), although C2Cl4 presents less scatter than CO. At two tall tower sites in the United States (WLEF, Wisconsin, and WITN, North Carolina), we found that in summertime the C2Cl4 (CO) versus fossil CO2 slope is on average up to 15% (25%) higher than in winter. We show that for C2Cl4 this seasonal variation is due to OH oxidation. For CO the seasonal variation is due to both chemistry and mixing with nonanthropogenic CO sources. In wintertime the three surrogate tracers SF6, C2Cl4, and CO are about equally as good indicators of the presence of fossil CO2. However, our model strongly underestimates the variability of SF6 at both towers, probably because of unaccounted for emissions. Hence poor knowledge of emission distribution hampers the use of SF6 as a surrogate tracer. From a practical point of view we recommend the use of C2Cl4 as a proxy of fossil CO2. We also recommend the use of tracers to separate fossil CO2. Despite the fact that the uncertainty on the regression slope is on the order of 30%, the tracer approach is likely to have less bias than when letting one model with one inventory emission map calculate the fossil CO2 distribution.
In an earlier report we identified specific modifications and substitutions of corticotropin releasing factor (CRF) that led to the discovery of antagonists with extended duration of action as ...compared to that of astressin {cyclo(30−33)dPhe12,Nle21,Glu30,Lys33,Nle38hCRF(12 - 41)}. These additional modifications included elongation of the peptide chain by three residues at the N-terminus, its acetylation, and the CαMeLeu27 substitution to yield cyclo(30−33)dPhe12, Nle21,CαMeLeu27,Glu30,Lys33,Nle38Ac-hCRF(9 - 41), which was found to be longer acting than astressin (Rivier, J.; et al. J. Med. Chem. 1998, 41, 5012−5019). To further increase the efficiency (potency, duration of action, and bioavailability) of this family of antagonists, we introduced two or more CαMe-leucine residues at positions shown in earlier studies to be favorable (Hernandez, J.-F.; et al. J. Med. Chem. 1993, 36, 2860−2867). Whereas the introduction of CαMe-leucine residues at positions 27 and either 18 (11), 37 (17), or 40 (19) resulted in dramatic increases in duration of inhibitory action in the adrenalectomized (adx) rat after intravenous injection, the same substitution at positions 27 and either 15 (7, 8), 17 (9), 19 (12, 13), or 41 (20) led to short acting analogues. Other substitutions by CαMeLeu at positions 27 and either 10 (4), 13 (5), 14 (6), 21 (14), 24 (15), 36 (16), or 38 (18) yielded analogues with duration of action intermediate between those mentioned above. Cyclo(30−33)dPhe12, Nle21,CαMeLeu27,Glu30,Lys33,Nle38,CαMeLeu40Ac-hCRF(9 - 41) (astressin B, 19) was one of the most efficacious analogues of this series (>4 h inhibition of ACTH secretion at 25 μg/adx rat). It was found to be even longer acting via subcutaneous administration in either an aqueous (>24 h inhibition of ACTH secretion at 100 μg/adx rat) or lipid milieu (DMSO/peanut oil, >24 h inhibition of ACTH secretion at 30 μg/adx rat) than after intravenous administration (<12 h inhibition of ACTH secretion at 100 μg/adx rat). We concluded that Cα-methylation at some positions may favor a bioactive conformation while also preventing degradation and/or elimination, resulting in significant extension of duration of action.
Approximately half of human-induced carbon dioxide (CO₂) emissions are taken up by the land and ocean, and the rest stays in the atmosphere, increasing the global concentration and acting as a major ...greenhouse-gas (GHG) climate-forcing element. Although GHG mitigation is now in the political arena, the exact spatial distribution of the land sink is not well known. In this paper, an estimation of mean European net ecosystem exchange (NEE) carbon fluxes for the period 1998-2001 is performed with three mesoscale and two global transport models, based on the integration of atmospheric CO₂ measurements into the same Bayesian synthesis inverse approach. A special focus is given to sub-continental regions of Europe making use of newly available CO₂ concentration measurements in this region. Inverse flux estimates from the five transport models are compared with independent flux estimates from four ecosystem models. All inversions detect a strong annual carbon sink in the southwestern part of Europe and a source in the northeastern part. Such a dipole, although robust with respect to the network of stations used, remains uncertain and still to be confirmed with independent estimates. Comparison of the seasonal variations of the inversion-based net land biosphere fluxes (NEP) with the NEP predicted by the ecosystem models indicates a shift of the maximum uptake period, from June in the ecosystem models to July in the inversions. This study thus improves on the understanding of the carbon cycle at sub-continental scales over Europe, demonstrating that the methodology for understanding regional carbon cycle is advancing, which increases its relevance in terms of issues related to regional mitigation policies.
The actual antidoping control rules applied in sports (as established by the International Olympic Committee and the International Sport Federations) state that a positive case is chemically ...established by the unequivocal detection of a forbidden parent molecule and/or any of its metabolite(s) in urine, no matter the amounts which were administered and when the drug was taken. Screening is accomplished most of the time by using GC–MS procedures. These have been optimized to detect most if not all of the forbidden compounds which are put on a list. Recently, attempts have been made on scalp hair to demonstrate the value of this matrix as a possible means for differentiating between therapeutic use and doping abuse. In particular, GC–mass selective detector and GC– high resolution MS were successfully applied to treated animals and body-builders for anabolic agents (steroids and beta-2-agonists) at high sensitivity detection (low ng/g level). Naturally occurring molecules, like testosterone and its metabolites, could also be differentiated from their synthetic counterparts. Positive cases are more often challenged in courts and retrospectivity in time of the drug(s) intake is becoming an important issue for evaluating the responsibility of the person. This is can be based on hair analyses if the drugs have been taken at regular intervals. Stimulants and narcotics are often used in sports like drug of abuse in the ordinary social contexts. On the other hand, anabolic agents, when taken to improve the physical performances, follow complex regimens with the mixing of various formulas and dosages. Scalp hair references ranges for these as well as for endogenous substances still wait to be established statistically for competing, well-trained athletes. The incorporation rate into blond or gray hair is poorer than that of dark colored hair raising the question of individuals equality against the controls, a very important matter of concern for the sport’s governing bodies. The frequency of hair cutting and short hair cuts necessary to gain speed in specific sports like swimming are other critical factors. On the other hands, irregular hair growth, associated with the washout effect through multiple washing and staining processes over expanded time intervals can cause concentrating or diluting effects. So far, a minority of prohibited substances could be detected in scalp hair with the sensitivity and specificity required in the context of the sport’s activities. From the above, clear limitations of the usefulness of hair analysis in doping control analysis are obvious until a lot more data relevant to this particular field have been collected.
Corticotropin-releasing factor (CRF) has previously been reported in rat testes in which it inhibits Leydig cells activity. However, recent studies in our laboratory have suggested that some of the ...effects originally attributed to CRF were instead due to the related peptide Urocortin 1 (Ucn 1) and that this latter hormone, not CRF, was detectable in Leydig cells. We show here that Ucn 1 a mixed CRF receptor (CRFR) type 1 and CRFR2 agonist and the CRFR1-selective peptide Stressin 1, but not Ucn 2 or Ucn 3 (both considered selective CRFR2 ligands), significantly blunt the testosterone response to human chorionic gonadotropin. The effect of Ucn 1 is observed regardless of whether this peptide is injected iv or directly into the testes, and it is reversed by the mixed CRFR1/R2 antagonist Astressin B. Blockade of GnRH receptors with the antagonist Azalin B does not interfere with the influence of Ucn 1, thereby demonstrating that pituitary luteinizing hormone does not appear to be involved in this model. Collectively these results suggest that Ucn 1, not CRF, is present in the rat testes and interferes with Leydig cell activity. However, whereas we previously reported that alcohol up-regulated gonadal Ucn 1 gene expression, CRF receptor antagonists were unable to reverse the inhibitory effect exerted by alcohol on human chorionic gonadotropin-induced testosterone release. The functional role played by testicular Ucn 1 in stress models characterized by blunted androgen levels therefore needs to be further investigated.
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