bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiovascular and survival effects of sympatho‐inhibitors in adriamycin‐induced cardiomyopathy in rats
Authors: Thomas Lionel , Bellmont Sandrine , Christen Marie‐Odile , Roche Benoît La , Monassier Laurent 
Published: November 2004

AbstractAdriamycin (ADR) is a widely used drug for the treatments of cancers. This study evaluates the effects of moxonidine and metoprolol on cardiac hemodynamics and survival in ADR‐induced left ventricular dysfunction (total dose of 20 mg/kg in a 4‐week regimen). Rats were treated with the centrally acting I1R agonist sympatho‐inhibitor, moxonidine, or with the non‐selective β‐adrenergic antagonist, metoprolol, during 1 month or until death. Treatments began 1 week after the onset of the ADR administration. Low doses (0.5 and 1 mg/kg/day) of moxonidine and metoprolol (10 mg/kg/day) improved cardiovascular function. High doses of moxonidine (3 mg/kg/day) and metoprolol (150 mg/kg/day) were cardiodepressive. Moxonidine and metoprolol both failed to improve survival. These data indicate that a treatment with these sympatho‐inhibitors can reduce the left ventricular dysfunction induced by ADR. Moreover, these cardioprotective effects where obtained even when ADR was used at a dose regimen usually employed for its antineoplastic effects in rodents. Nevertheless, in this particular cardiomyopathy, we did not find any association between improvements of functional parameters and survival whatever the drug and the dose used. This problem points out the difficulty to prevent, at least with sympatho‐inhibitory drugs alone, the mortality linked to the chronic cardiotoxicity of ADR.
Dopamine, depression and antidepressants
Authors: Dailly Eric , Chenu Franck , Renard Caroline E. , Bourin Michel 
Published: November 2004

AbstractThe relationship between depression and dopamine deficiency in the mesolimbic pathway has been hypothesized for many years. The experimental studies with animal models of depression and the human studies implicate the role of the dopamine system in depression. Not only do dopaminergic receptor agonists, but also antagonists such as olanzapine exhibit antidepressant effects associated with standard antidepressants in patients with treatment‐resistant depression. This paradoxical result suggests that further investigations are necessary to understand the role played by dopamine in depression.
Pharmacogenomics in cardiovascular clinical trials
Authors: Shah R. , Darne B. , Atar D. , Abadie E. , Adams K.F. , Zannad F. ,   on behalf of the participants in the 5th Cardiovascular Clinical Trialists Workshop
Published: November 2004

AbstractGenomics – having quickly emerged as the central discipline in basic science and biomedical research – is poised to take the center stage in clinical medicine as well over the next few decades. Although there is no specific regulatory guideline on the application of pharmacogenetics to drug development, some recommendations are already included in several published guidelines on drug development. The patients more likely to provide the most valuable information on the specific contribution of a given gene or its variant are those who fail to respond to a drug (‘therapeutic failures’) and those who develop toxicity to the drug. However, before drawing definite conclusions on subgroups following pharmacogenomic analyses, one must be aware of disease classification, data collection, and how much is known about the disease process. It seems reasonable to collect genomic DNA from all patients enrolled in clinical drug trials (along with appropriate consent to permit pharmacogenetic studies) for the purpose of post hoc analyses. One exception to post hoc genomic analysis is when patients with a specific genotype are excluded from randomization into a clinical trial. Physicians will need to understand the concept of genetic variability, its interactions with the environment (e.g. drug–drug or drug–disease interactions), and its implication for patient care.
Impairment of smooth muscle function of rat thoracic aorta in an endothelium‐independent manner by long‐term administration of NG‐nitro‐l‐arginine methyl ester
Authors: López Ruth M. , Ortíz Cindy S. , Ruíz Antonio , Vélez Juan M. , Castillo Carlos , Castillo Enrique F. 
Published: November 2004

AbstractIn this study, we aimed to elucidate whether the daily hypertensive dose of long‐term NG‐nitro‐l‐arginine methyl ester (l‐NAME) treatment, could make a difference between endothelial and smooth muscle functions in rat thoracic aorta. We test the hypothesis that high‐dose, long‐term l‐NAME treatment has a depressive effect on vascular smooth muscle contractile activity which is not related with nitric oxide (NO) synthesis inhibition. After 14 days of treatment, isometric tension and 45Ca2+ influx were measured in aortic tissues isolated from l‐NAME10 and l‐NAME100 hypertensive (10 and 100 mg/kg/day, systolic blood pressures 167 ± 7 and 172 ± 10 mmHg, respectively) and control normotensive rats (132 ± 7 mmHg). In l‐NAME10‐ and l‐NAME100‐treated rats, acetylcholine‐induced relaxation in aortic rings was suppressed with no significant difference between the treatments. l‐NAME100 (but not l‐NAME10) treatment, significantly inhibited contractile responses to phenylephrine, angiotensin II, and K+ (80 mm) in endothelium‐intact tissues. The effect of l‐NAME100 on phenylephrine‐induced contractile responses was not observed after 3 days of treatment. In endothelium‐denuded aortic tissues of l‐NAME100 (but not l‐NAME10)‐treated rats, phenylephrine (1 × 10−6 m)‐ and K+ (80 mm)‐induced contractions and 45Ca2+ influxes were significantly reduced. In Ca2+‐free medium (0.1 mm EDTA), on the contrary, the transient contractions obtained by either phenylephrine (1 × 10−6 m) or caffeine (1 × 10−2 m), or the sustained contractions induced by 12‐o‐tetradecanoylphorbol‐13‐acetate (1 × 10−6 m; a protein kinase C activator) in endothelium‐denuded aortic rings, were not modified by both l‐NAME treatments. These results indicate that in aortic rings from l‐NAME hypertensive rats, low and high doses, long‐term l‐NAME administration may be associated with equivalent inhibition in NO‐dependent vasodilator tone (corresponding to equivalent hypertension values); whereas only high‐dose, long‐term l‐NAME administration produces an endothelium‐independent decrease in vasocontrictor activity, at least partly explained by a reduction in extracellular Ca2+ influx.
Effect of Yucca schidigera with or without nisin on ruminal fermentation and microbial protein synthesis in sheep fed silage‐ and hay‐based diets
Authors: SANTOSO Budi , MWENYA Benson , SAR Chetra , GAMO Yuko , KOBAYASHI Takeo , MORIKAWA Reina , TAKAHASHI Junichi 
Published: November 2004

ABSTRACTA 4 × 6 Youden square design was used to study manipulating effect of Yucca schidigera with or without nisin on rumen fermentation characteristics and microbial protein synthesis in sheep fed silage‐ and hay‐based diets. Four ruminally canulated wethers were given isonitrogenous diets of timothy silage and concentrate (85:15) (S), and timothy hay and concentrate (60:40) (H), on DM basis. The six experimental diets were: (i) S; (ii) S + 240 ppm of Yucca schidigera (SY); (iii) S + 240 ppm of Yucca schidigera + 6 mg/kg bodyweight (BW)0.75 of nisin (SYN); (iv) H; (v) H + 240 ppm of Yucca schidigera (HY); and (vi) H + 240 ppm of Yucca schidigera + 6 mg/kg BW0.75 of nisin (HYN). Rumen pH was higher (P < 0.01) in sheep fed SYN diet than those fed S diet. Concentration of ammonia‐N (NH3‐N) was significantly lower (P < 0.05) in sheep fed SY, SYN, HY, HYN than those of S and H. Total volatile fatty acids concentration was significantly lower (P < 0.05) in HYN than in H diet and tended to be higher in sheep fed H diets than those fed S diets. There was a significantly higher (P < 0.01) efficiency of microbial nitrogen synthesis in the rumen of sheep fed on HY diet than those fed on H diet.
TEMPORAL CODING AND OSCILLATIONS IN THE VISUAL CORTEX OF MAMMALS
Authors: PARODI OLIVIER 
Published: November 2004

Information coding by patterns of spike rates is incompatible with the experimental results on fast recognition of figures or scenes, which may be explained only on the basis of a one-spike-per-neuron computation. It had been suggested that coding may be achieved by means of the spikes arrival times. It is shown here that such a coding will be jammed up everytime a perceptive process extends over several spikes, unless the input integrator neurons are periodically reset. This resetting may be responsible for the periodic burst firing and the oscillations of the local field potential which have been experimentally found in the cases of motion detection or of sustained attention. A presynchronisation process is required, for the initial coding and for scene fragmentation, and may be achieved by an electrical interneuronal coupling, which is shown to be both realistic and efficient. Information decoding may be implemented by neurons operating in a correlator mode, which is analysed.
Toxicity and chemistry of aspen wood leachate to aquatic life: Field study
Authors: Taylor Barry R. , Carmichael N. Bruce 
Published: November 2004

Abstract
A dark, toxic leachate has been observed around woodpiles of trembling aspen (Populus tremuloides Michx.) cut in winter for pulp or structural lumber. We measured production of leachate from 18 m3 of harvestable aspen logs stacked in an open field near Dawson Creek, British Columbia, Canada. The logpile began producing leachate during the first winter thaw and continued to do so for the duration of the two-year study (mean, 250 L/collection). Aspen leachate was characterized by dark color, acidic pH (5.0-6.5), elevated conductivity (200-500 μS/cm), high to very high biochemical oxygen demand (500-5,000 mg/L) and total organic carbon concentrations (500-2,000 mg/L), variable levels of phenolic compounds (2-27 mg/L), and low dissolved oxygen tensions (&lt;2 mg/L). In tests with rainbow trout (Oncorhynchus mykiss), Daphnia magna, and luminescent bacteria, the leachate varied from weakly toxic (median lethal concentration, &gt;10%) to very toxic (median lethal concentration, &lt;1%). The volume of leachate generated by the logpile was correlated with total precipitation (rain or snow) since the last collection. Loads of chemical constituents or toxicity (lethal concentration × volume) in the leachate did not decline over the duration of the study. Less than 10% of the total mass of leachable material in the aspen logs was removed during two years of exposure.
Effects of ammonia on juvenile unionid mussels (Lampsilis cardium) in laboratory sediment toxicity tests
Authors: Newton Teresa J. , Allran John W. , O'Donnell Jonathan A. , Bartsch Michelle R. , Richardson William B. 
Published: November 2004

Abstract
Ammonia is a relatively toxic compound generated in water and sediments by heterotrophic bacteria and accumulates in sediments and pore water. Recent data suggest that unionid mussels are sensitive to un-ionized ammonia (NH3) relative to other organisms. Existing sediment exposure systems are not suitable for ammonia toxicity studies with juvenile unionids; thus, we modified a system to expose juveniles to ammonia that was continuously infused into sediments. This system maintained consistent concentrations of ammonia in pore water up to 10 d. Juvenile Lampsilis cardium mussels were exposed to NH3 in pore water in replicate 96-h and 10-d sediment toxicity tests. The 96-h median lethal concentrations (LC50s) were 127 and 165 μg NH3-N/L, and the 10-d LC50s were 93 and 140 μg NH3-N/L. The median effective concentrations (EC50s) (based on the proportion affected, including dead and inactive mussels) were 73 and 119 μg NH3-N/L in the 96-h tests and 71 and 99 μg NH3-N/L in the 10-d tests. Growth rate was substantially reduced at concentrations between 31 and 76 μg NH3-N/L. The lethality results (when expressed as total ammonia) are about one-half the acute national water quality criteria for total ammonia, suggesting that existing criteria may not protect juvenile unionids.
Stress status of gudgeon (Gobio gobio) from rivers in Switzerland with and without input of sewage treatment plant effluent
Authors: Faller Patrick , Kobler Bernd , Peter Armin , Sumpter John P. , Burkhardt-Holm Patricia 
Published: November 2004

Abstract
To assess the importance of sewage treatment plant effluents on fish health, we studied gudgeon in two rivers in the Swiss midlands (Canton Lucerne). Both rivers receive pollution from diffuse sources, while one also receives the effluent of a sewage treatment plant. Male and female gudgeon during and outside of the spawning season were compared with respect to reproductive parameters and health status across both rivers as well as upstream and downstream of the STP. Several biomarkers were studied, including cytochrome P4501A, 7-ethoxyresorufin-O-deethylase, plasma vitellogenin, ovotestis, lipid, liver histology, condition factor, gonadosomatic index, splenosomatic index, parasites of spleen and liver, population structure, and species diversity. Gudgeons of both rivers exhibited signs of a moderately impaired health status. By a stepwise backward analysis, the cytochrome P4501A content, the splenosomatic index, and the incidence of parasites in the liver were found to provide the best discrimination of the three sampling sites. Evidence of a significant elevation in response to the sewage treatment plant effluent was found neither in vitellogenin concentration nor in the ovotestis rate. While population structure was analyzed upstream and downstream of the sewage treatment plant, only gudgeons of the latter site revealed a disturbed population structure, most probably caused by a former nitrite discharge.
Integrating enzymatic responses to organic chemical exposure with total oxyradical absorbing capacity and dna damage in the european eel Anguilla anguilla
Authors: Regoli Francesco , Winston Gary W. , Gorbi Stefania , Frenzilli Giada , Nigro Marco , Corsi Ilaria , Focardi Silvano 
Published: November 2004

Abstract
In this work, susceptibility to oxidative stress was analyzed under laboratory conditions in the European eel Anguilla anguilla. Eels were treated with increasing concentrations of benchmark environmental pollutants, namely, benzo[a]pyrene ([BaP], at 0, 0.1, 1, 10, and 50 mg/kg), β-naphthoflavone ([BNF], at 0, 0.1, 1, 10, and 50 mg/kg), Arochlor® 1254 (at 0, 0.1, 1, 10, and 50 mg/kg), and 2,3,7,8-tetrachlorodibenzo p-dioxin ([TCDD], at 0, 0.01, 0.1, 1, and 2 μg/kg). The integral relationships were analyzed between induction of ethoxyresorufin O-deethylase (EROD) activity, its involvement in perturbing oxyradical metabolism, and the role of cytochrome P450 and/or oxidative stress in mediating genotoxic effects. To reveal whether the oxidative status in exposed organisms was altered as a result of chemical exposure, measurements of the main endogenous antioxidant defenses were integrated with the measurement of total oxyradical scavenging capacity (TOSC) toward peroxyl radicals and hydroxyl radicals (·OH). This approach permits discriminating the resistance of a tissue toward different forms of oxyradicals, thereby indicating a differential role for specific reactive oxygen species (ROS) in perturbing the balance between prooxidant and antioxidant mechanisms. All the analyzed chemicals promoted EROD induction (reflective of CYP1A) and altered either the levels or the activities of the antioxidants studied, which might be anticipated to exert alterations in oxyradical metabolism. Analysis of TOSC suggested the prevalence of metabolic oxidative pathways leading to the more reactive ·OH on exposure to the chemicals studied. Of these chemicals, enhanced EROD activity correlated with genotoxic damage only in the cases of the nonhalogenated hydrocarbons BaP and BNF. The highest degree of genotoxic damage was consistently observed in organisms in which the capacity to absorb or scavenge ·OH was lowest. These data suggests a general relationship between oxidative stress and loss of DNA integrity in juvenile eels exposed to the chemicals studied herein.
Exposure patterns of perfluorooctane sulfonate in aquatic invertebrates from the Western Scheldt estuary and the southern North Sea
Authors: Van de Vijver Kristin I. , Hoff Philippe T. , Van Dongen Walter , Esmans Eddy L. , Blust Ronny , De Coen Wim M. 
Published: November 2004

Abstract
Over the past decades little research has been conducted on the environmental behavior and effects of fluorinated organochemicals (FOCs). Recently it has been reported that perfluorooctane sulfonic acid (PFOS) is occurring worldwide. Little is known about the PFOS levels in organisms originating from the southern North Sea and the Western Scheldt estuary. In this study, we determined, for the first time, the PFOS-exposure levels in Crangon crangon, Carcinus maenas, and Asterias rubens from these ecosystems. Concentrations on a wet-weight basis in soft tissues of shrimp, crab, and starfish ranged from 19 to 520 ng/g, from 24 to 877 ng/g, and from 9 to 176 ng/g, respectively. These results show the existence of a PFOS pollution gradient in organisms along the Western Scheldt estuary, with the highest concentrations near Antwerp. The range of PFOS levels in shrimp and crab are slightly higher in coastal regions compared with sampling sites in open water. This study shows widespread distribution of PFOS in the Belgian and Dutch marine and estuarine environment at rather high concentrations.
Effect of declining toxicant concentrations on algal bioassay endpoints
Authors: Simpson Stuart L. , Roland Marie G. E. , Stauber Jenny L. , Batley Graeme E. 
Published: November 2004

Abstract
Sorption, degradation, volatilization, and uptake by test organisms cause concentrations of many toxicants to decline during toxicity testing. Despite the recognition of this occurring, nominal, measured initial or time-averaged concentrations are commonly used for the calculation of inhibitory or effect concentrations from toxicity test data. Because a premise of constant exposure is assumed but not met in these calculations, the toxicity of the test water may be significantly underestimated. Laboratory experiments using a 72-h algal growth inhibition bioassay and copper as a toxicant are used to demonstrate that calculated inhibitory concentrations will often be underestimated twofold if losses of copper occurring over the 72-h test duration are not considered. A simple model is presented for toxicant concentration decline and for the relationship between algal growth rate and toxicant concentration. This model is used to demonstrate the magnitude that calculated inhibitory concentrations may be underestimated if concentration declines are not considered for a series of different concentration decline scenarios. For a toxicant whose concentration declines exponentially to less than 5% of its original value within 36 h of a 72-h test, the inhibitory concentration is shown to be underestimated by a factor of 50.
A review and comparison of models for predicting dynamic chemical bioconcentration in fish
Authors: Barber M. Craig 
Published: November 2004

Abstract
Over the past 20 years, a variety of models have been developed to simulate the bioconcentration of hydrophobic organic chemicals by fish. These models differ not only in the processes they address but also in the way a given process is described. Processes described by these models include chemical diffusion through the gill's interlamellar water, epithelium, and lamellar blood plasma; advective chemical transport to and from the gill by ventilation and perfusion, respectively; and internal chemical deposition by thermodynamic partitioning to lipid and other organic phases. This article reviews the construction and associated assumptions of 10 of the most widely cited fish bioconcentration models. These models are then compared with respect to their ability to predict observed uptake and elimination rates using a common database for those model parameters that they have in common. Statistical analyses of observed and predicted exchange rates reveal that rates predicted by these models can be calibrated almost equally well to observed data. This fact is independent of how well any given model is able to predict observed exchange rates without calibration. The importance of gill exchange models and how they might by improved are also discussed.
Effect of pH and release® on two life stages of four anuran amphibians
Authors: Edginton Andrea N. , Stephenson Gerald R. , Sheridan Patrick M. , Thompson Dean G. , Boermans Herman J. 
Published: November 2004

Abstract
Using three native Canadian and one exotic anuran species, the interactive toxicity of pH and the forestry usedherbicide Release® (triclopyr [3,5,6-trichloro-2-pyridl-oxyacetic acid]) was assessed. Embryonic and larval (Gosner 25) stages of Rana pipiens, Rana clamitans, Bufo americanus, and Xenopus laevis were exposed to treatments for at least 96 h in a staticrenewal system using a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach to obtain confidence intervals. Consistent trends of greater toxicity with lower pH were observed, with the majority of models (five of seven models) showing significant (p &lt; 0.05) inverse relations. Larval lethal concentration estimates were eight to twenty-three times less than those observed for embryos, indicating that the larval stages were more sensitive to treatments. Further, the median lethal concentration (LC50) values for the larvae were below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities for Release. Species sensitivity was similar, with an average larval 96-h LC50 of 0.89 mg acid equivalents (AE)/L at pH =.5 and 1.6 mg AE/L at pH 7, suggesting that X. laevis is a reasonable surrogate for native amphibians in laboratory toxicity testing. For the embryo tests, R. pipiens were slightly less sensitive in comparison with the other three species. Based on a hazard quotient analysis (EEC/LC50 &gt; 1) for the most sensitive larval life stages, higher tier ecotoxicological testing under more realistic environmental conditions is strongly recommended.