Diagnostic potential of natriuretic peptides in the occult phase of golden retriever muscular dystrophy cardiomyopathy

The objective of the study was to determine whether the plasma concentrations of atrial and brain natriuretic peptides (ANP and BNP, respectively) could be reliable markers of cardiac alterations during occult cardiomyopathy in Golden Retriever Muscular Dystrophy (GRMD). Fifty Golden Retrievers without any clinical or radiographic sign of heart disease were included in this study (21 GRMD dogs and 29 controls). Controls and GRMD dogs were divided into 2 subgroups according to age (< and > or =12 months old, respectively). All dogs underwent echocardiography and determination of BNP and ANP plasma concentrations by radioimmunoassay. No ventricular dilatation or dysfunction was observed in either control or GRMD dogs. ANP plasma concentration did not differ significantly between controls and GRMD dogs (mean +/- SD = 72 +/- 49 versus 58 +/- 23 pg/mL, respectively, P = .21). This finding was confirmed in both subgroups of dogs (ie, those < and > or =12 months old). In contrast, BNP plasma concentrations were significantly higher in GRMD dogs than in controls (mean +/- SD = 117 +/- 92 versus 46 +/- 22 pg/mL, respectively, P < .05). In dogs > or =12 months old, sensitivity and specificity of BNP for identifying GRMD with a cutoff of 65 pg/mL were 78 and 86%, respectively. For the same cutoff value, sensitivity dropped to 42%, whereas specificity reached 100% in dogs <12 months old. In conclusion, BNP may be a useful biochemical marker of asymptomatic cardiomyopathy. However, this peptide does not allow very early detection because its optimal discriminatory power was observed in adult dogs (ie, > or =12 months of age).     

Spatial activity and expression of plasma membrane H+-ATPase in stem xylem of walnut during dormancy and growth resumption

Plasma membrane H+-ATPase (PM H+-ATPase) plays a key role in nutrient transport, stress responses and growth. To evaluate proton motive force differences between apical and basal parts of acrotonic 1-year-old shoots of walnut (Juglans regia L. cv 'Franquette') trees, spatial and seasonal changes in PM H+-ATPase were studied in mature xylem tissues. During both the dormancy and growth resumption periods, and in both the apical and basal parts of the stem, PM H+-ATPase activity showed positive correlations with the amount of immunodetectable protein. In spring, at the time of growth resumption, higher activities and immunoreactivities of PM H+-ATPase were found in the apical part of the stem than in the basal part of the stem. In spring, the decrease in xylem sugar concentration reflected the high sugar uptake rate. Our data suggest that PM H+-ATPase plays a major role in the uptake of carbohydrates from xylem vessels during growth resumption. These results are discussed in the context of the acrotonic tendency of walnut shoots.     

Natural hazards and genetic diversity in rice

Rice crop diversity hasdecreased dramatically in the recent past.Understanding the causes that underlie theevident genetic erosion is critical for thefood security of subsistence rice farmers andbiodiversity. Our study shows that farmers inthe northeastern Philippines had a markedreduction in rice diversity from 1996 to 1998.The ultimate causes were a drought resultingfrom the El Niño phenomenon in 1997 andflooding due to two successive typhoons in1998. The proximate causes, however, includedlocal water control factors, limitations in thehousehold and village-level seedinfrastructure, farm location in relation tothe goods and services necessary to obtainseeds, policies and programs of the Departmentof Agriculture, and the characteristics of therice varieties themselves. The implications ofour study are that genetic erosion is notalways the result of purposeful acts by farmersnor is it necessarily gradual. Improvingon-farm seed technology will stabilize the seedproduction, distribution, and use system andthereby enhance household food security.Ultimately, rice diversity will be improvedonly if diversity is a safe and viable optionfor farmers. Therefore, public policy thatsupports farmers who maintain a diverse set ofcultivars is critical for any on-farmconservation strategy.     

Quantitative variation as a tool for detecting human-induced impacts on genetic diversity

We propose quantitative genetic variation as a useful tool complementary to molecular variation in order to detect changes in biodiversity caused by different human-induced activities. We simulated a metapopulation setting under a number of realistic scenarios caused by anthropogenic activities (population isolation, reduced carrying capacity or reproductive rates, shifts in the local optima, and enhanced environmental variation or mutational rates). The effects on diversity of these scenarios were assessed for neutral variation estimated from molecular markers and for an additive quantitative trait that represents a typical morphological characteristic subject to stabilising selection promoting local adaptation to environmental conditions. The results show that monitoring quantitative genetic variation can be more informative than neutral variation to detect some human-induced environmental or genetic impacts on diversity, both at intra and interpopulation levels. We also compared the precision of diversity estimates obtained from molecular markers and quantitative traits. Under low migration rates and typical selection intensities for the quantitative trait, the precision of estimates can be substantially larger for a quantitative trait than for a single molecular marker. Thus, about 10-20 (2-4) independent markers are necessary for the precision of estimates of heterozygosity (population differentiation) from molecular markers to reach that of genetic variances (differentiation) from quantitative traits.     

Effect of adjacent agricultural habitat on the distribution of passerines in natural grasslands

Habitat heterogeneity has often been acknowledged as a key factor determining which species occur in a landscape, but we still know little on the nature and relative importance of the processes controlling species distribution and abundance within complex landscape mosaics. We used a framework defined by the compensation, supplementation and complementation models to study the distribution of four species of passerines typical of steppe habitats and identify the degree to which landscape context accounts for their distribution in the steppe-agriculture mosaic of the Crau, southern France. Steppe habitat was the best predictor of species distribution in all cases and that densities were highest in steppe. One of these species, the Calandra lark, is strictly tied to the natural steppe habitats independently of its context. For another species, the Tawny pipit, we document a significant positive effect of the presence, near steppe habitat, of extensive pastoral habitats, such as fallows and grazed crops. Finally, the abundance of the two remaining species, Skylark and Short-toed lark, was negatively affected by the presence of non-herbaceous habitats in the vicinity of steppe habitat. This suggests that the quality of the steppe habitat, as perceived by these species is conditional to the nature of adjacent habitats. Our results suggest that the management of the context in which steppe habitat is imbedded will significantly affect the distribution and abundance of this group of passerines and determine both habitat quality and conservation value at a landscape scale.     

Detection of Coxiella burnetii, the agent of Q fever, in oviducts and uterine flushing media and in genital tract tissues of the non pregnant goat

The aim of the present study was the detection and quantification of Coxiella burnetii DNA in the flushing media (oviducts and uterine horns) and genital tract tissues of non pregnant goats from 20 goats chosen at random from 86 goats originating from 56 different breeding herds in south-west France. The serological prevalence rate of C. burnetii in the study population was 70.3%.The DNA of C. burnetii was identified using conventional PCR in the flushing media from the oviducts and uterus in 8/20 goats (40%) and in genital tract tissues (oviduct, uterus and ovary) in 5/20 goats (25%). This study clearly shows for the first time that the media used to flush the oviducts or uterine horns, collected using the standard embryo harvesting technique in goats, are susceptible to infection with C. burnetii. The 16 conventional PCR-positive samples were also analyzed using real-time PCR. The bacterial load of the oviduct and uterine flushing media varied from 2.9 × 10⁴ to 7.5 × 10⁶ bacteria per flushing medium, while the bacterial load of the tissue samples varied from 1.0 × 10² to 1.5 × 10⁵ bacteria per mg of tissue. The infection of genital tract flushing media and tissues is a risk factor for the transmission of C. burnetii from donor to recipient during embryo transfer or to the embryo and fetus when gestation is pursued to term.     

Atmospheric Total Suspended Particulate Trace Element Identification by XRF at Ilha Grande, State of Rio De Janeiro, Brazil

Phosphorus, manganese, sulfur (S), lead, and strontium of atmospheric total suspended particulate matter, sampled during the rainy season and the dry season 2002 at the Ilha Grande Island (Rio de Janeiro State, Brazil) have been analyzed by XRF techniques. The results showed total mean concentrations of 27?±?16 ng P m^-3, 11?±?7 ng Mn m^-3, 159?±?126 ng S m^-3, 4.3?±?2.6 ng Pb m^-3, and 208?±?148 ng Sr m^-3. Generally, there is no clear influence of the two different climatic periods on the concentrations of most analyzed trace elements, with exception of sulfur the mean concentration of which, during the dry season, is about 60% higher than during the rainy season. This is probably due to biomass burning, a common practice in the Brazilian Southeast and Amazon region and/or to the presence of marine aerosols. The linear correlation coefficients strongly suggest the same source for P, Pb, and Mn. Some Pb, Mn, and P concentrations are in the range of typical values of urban areas. Potential sources of such elements are the urban and industrial emissions from the States of Rio de Janeiro and/or São Paulo.     

Comparative adverse cardiac effects of pimobendan and benazepril monotherapy in dogs with mild degenerative mitral valve disease: a prospective, controlled, blinded, and randomized study

BACKGROUND: Pimobendan (PIMO) is an inodilator that may have some beneficial effects in canine degenerative mitral valve disease (MVD). However, little information is available about its cardiac effects in dogs without systolic myocardial dysfunction. HYPOTHESIS: Compared to benazepril (BNZ), an angiotensin-converting enzyme inhibitor, PIMO may worsen valve regurgitation in early canine MVD. ANIMALS: Twelve Beagles with asymptomatic MVD were randomized into 2 groups (n = 6) receiving BNZ or PIMO at dosages of 0.25 mg/kg PO q24h and q12h respectively, for 512 days. METHODS: The study followed a blinded, randomized, prospective, and parallel group design. After day 512, the dogs were necropsied, and cardiac histopathology was performed in a blinded manner. RESULTS: A significant treatment effect was observed as soon as day 15 with increased systolic function in the PIMO group by comparison to baseline value as assessed by fractional shortening (P < .0001) and tissue Doppler variables (P = .001). Concurrently, the maximum area and peak velocity of the regurgitant jet signal increased (P < .001), whereas these variables remained stable in the BNZ group. Histologic grades of mitral valve lesions were more severe in the PIMO group than in the BNZ group. Moreover, acute focal hemorrhages, endothelial papillary hyperplasia, and infiltration of chordae tendinae with glycosaminoglycans were observed in the mitral valves of dogs from the PIMO group but not in those of the BNZ group. CONCLUSIONS AND CLINICAL IMPORTANCE: PIMO has adverse cardiac functional and morphologic effects in dogs with asymptomatic MVD. Additional investigation in dogs with symptomatic MVD is now warranted.     

Core-derived historical records of suspended sediment origin in a mesoscale mountainous catchment: the River Bléone, French Alps

Purpose

Quantifying suspended sediment fluxes and dynamics across mountains, and identifying the origin of sediment in severely eroded areas, are of primary importance for the management of water resources. This contribution aims to generalise previous results from suspended sediment fingerprinting obtained during 2007?C2009 in a mesoscale Alpine catchment (the Bléone River; 905?km²) in France, and to assess variability in sediment sources throughout the second half of the twentieth century.

Materials and methods

Sediment fingerprinting, based on elemental geochemistry and radionuclide measurements, was conducted on a sediment core collected in an alluvial floodplain at the basin outlet. This technique was combined with hydro-sedimentary time-series to reconstruct the origin of suspended sediment deposited at this location over the last 50?years.

Results and discussion

Interpretation of sedimentation based on historical hydrological databases corroborates core dating obtained with ¹³⁷Cs and ²¹⁰Pb_xs activity measurements. Black marls and (marly) limestone sources provided the main fraction of sediment throughout the sequence (40 and 22?%, respectively). However, we also found evidence for the occurrence of major floods carrying large quantities of sediment originating from Quaternary deposits and conglomerates (25 and 16?%, respectively). The variability of sediment sources throughout the sequence may reflect the spatial variability of rainfall within the catchment, which in turn reflects its origin. However, the relatively homogeneous sediment composition throughout the sequence confirms that core-derived information is representative of widespread flood events.

Conclusions

These results are consistent with those obtained in previous studies. They also outline the need to take into account the entire grain size range of fine sediment in order to provide an overall picture of sediment sources and transfers within highly erosive catchments. This study also emphasizes the importance of using archival data to validate the results of sediment fingerprinting studies conducted during short contemporary monitoring programmes, and to extend fingerprinting of sediment sources over longer time-scales which include large and widespread floods.     

Photolysis of the herbicide sulcotrione: formation of a major photoproduct and its toxicity evaluation

BACKGROUND: Sulcotrione is a selective herbicide marketed for use in maize since 1993, but its environmental fate is not yet fully elucidated. A major metabolite resulting from cleavage between the two ring moieties, leading to 2‐chloro‐4‐mesylbenzoic acid (CMBA), has been identified; it presents a rather low toxicity. In photochemical studies this compound has also been claimed to be formed in high proportions. The present authors recently found that, under irradiation, sulcotrione mainly yields a cyclization product (CP). Thus, Sulcotrione photochemistry is still a matter of debate. The aim of the present work was to give an unequivocal answer to this issue. The potential toxicity of CP, CMBA and sulcotrione towards three organisms considered as representative of aquatic ecosystems was also evaluated. RESULTS: The main transformation product of sulcotrione is the cyclization product (CP), and CMBA is formed in smaller amounts. For the toxicological approach, the tested organisms were a bacterium, Vibrio fischeri (Bejerinck) Lehmann & Neumann, an alga, Pseudokirchneriella subcapitata (Korshikov) Hindak, and a protozoan, Tetrahymena pyriformis (Ehrenberg) Lwoff. Sulcotrione is more harmful towards the alga, but CP is more toxic to the bacterium and the protozoan. It must be noted that the measured toxicities are nonetheless rather low. CONCLUSION: On irradiation, sulcotrione mainly gives the photocyclization product, which presents a higher toxicity than sulcotrione and CMBA. This cyclization product should thus be considered in sulcotrione environmental risk assessment. Copyright © 2008 Society of Chemical Industry