Monitoring of urea and potassium by reverse iontophoresis in vitro

in Pharmaceutical Research (2007), 24(6), 1131-1137

Purpose. Reverse iontophoresis is an alternative to blood sampling for the monitoring of endogenous molecules. Here, the potential of the technique to measure urea and potassium levels non-invasively, and ... [more ▼]

Purpose. Reverse iontophoresis is an alternative to blood sampling for the monitoring of endogenous molecules. Here, the potential of the technique to measure urea and potassium levels non-invasively, and to track their concentrations during hemodialysis, has been examined. Materials and Methods. In vitro experiments were performed to test (a) a series of subdermal urea and potassium concentrations typical of the pathophysiologic range, and (b) a decreasing profile of urea and potassium subdermal concentrations to mimic those which are observed during hemodialysis. Results. (a) After 60-120 min of iontophoresis, linear relationships (p < 0.05) were established between both urea and potassium fluxes and their respective subdermal concentrations. The determination coefficients were above 0.9 after 1 h of current passage using sodium as an internal standard. (b) Reverse iontophoretic fluxes of urea and K+ closely paralleled the decay of the respective concentrations in the subdermal compartment, as would occur during a hemodialysis session. Conclusions. These in vitro experiments demonstrate that urea and potassium can be quantitatively and proportionately extracted by reverse iontophoresis, even when the subdermal concentrations of the analytes are varying with time. These results suggest the non-invasive monitoring of urea and potassium to diagnose renal failure and during hemodialysis is feasible, and that in vivo measurements are warranted. [less ▲]

Monitoring of Yersinia enterocolitica in murine and bovine feces on the basis of the chromosomally integrated luxAB marker gene

in Applied & Environmental Microbiology (1992), 58(3), 1024-1026

We previously integrated the luxAB gene into the Yersinia enterocolitica chromosome. In this article, we assessed, by luminometry, the survival of the engineered strain KNG1024 in the digestive tracts of ... [more ▼]

We previously integrated the luxAB gene into the Yersinia enterocolitica chromosome. In this article, we assessed, by luminometry, the survival of the engineered strain KNG1024 in the digestive tracts of mice and cows. In situ detection and a count of the released strain were performed on feces from orally inoculated BALB/c mice for 24 days. This method is a rapid and reliable system for long-term monitoring of genetically engineered bacteria. In cow feces, the count of Y. enterocolitica ranged from 210 to 6,000 CFU/g of feces. This very low count was not detectable by direct luminometry [less ▲]

Monitoring Pichia anomala strain K and Candida oleophila strain O, antagonistic yeasts on apple surface

Poster (2001)

Monitoring population decline: can transect surveys detect the impact of the Ebola virus on apes?

in Oryx (2008), 42(3), 367-374

In 2004 the Ebola virus caused a drastic decline in western gorilla Gorilla gorilla abundance at Lokoue´ Bai, a clearing in Odzala National Park, Republic of Congo. This decline was detected by ... [more ▼]

In 2004 the Ebola virus caused a drastic decline in western gorilla Gorilla gorilla abundance at Lokoue´ Bai, a clearing in Odzala National Park, Republic of Congo. This decline was detected by observations of gorillas visiting the clearing. We confirm that the sympatric chimpanzee Pan troglodytes population was also affected by the Ebola outbreak, and test whether the decline in the ape population would have been detected with linetransect surveys, the most commonly used wildlife monitoring methodology in Central Africa. We also evaluate the potential of transect surveys for describing the extent and pinpointing the timing of drastic population declines when this information is not known from other evidence. Both nest survey using the marked nest count method and standing stock survey of other signs of ape presence (dung, feeding remains, prints) were able to detect the decline. However, only nests and dung were reliable indices for estimating the magnitude of the decline and accurately pinpointing the timing. It was necessary to pool data across many survey replicates because of small samples sizes. Our results suggest that transects methods are able to detect drastic changes in ape abundance but that large sample sizes are necessary to achieve adequate statistical power. We therefore recommend that those intending to use transect methods as tools for monitoring large forest mammals evaluate in advance how much effort will be necessary to detect meaningful changes in animal abundance. [less ▲]

Monitoring soil organic carbon in croplands using imaging spectroscopy (moca project)

Conference (2008, February 12)

The detection of changes in soil organic carbon (SOC) concentration is essential in both the assessment of SOC sequestration and soil quality. Within the EU soil thematic strategy the depletion of organic ... [more ▼]

The detection of changes in soil organic carbon (SOC) concentration is essential in both the assessment of SOC sequestration and soil quality. Within the EU soil thematic strategy the depletion of organic matter is mentioned as one of the major threats to the soil resource. As one of the first countries Luxemburg has taken the initiative to monitor the SOC concentration of individual fields to allow for eventual CO2 credits and as an indicator for good agro-ecological conditions (GAEC). The aim of this project is to develop an efficient and operational methodology to detect SOC changes in croplands using Imaging Spectroscopy and to map the SOC contents of croplands with high resolution and minimal calibration. [less ▲]

Monitoring the biodiversity and population ecology of fish in the Belgian Meuse Rivier by the use of fishpasses. A 12-year study at the Visé-Lixhe dam.

Conference (2001, December)

Monitoring the evolution of irrigated areas with Landsat images using backward and forward change detection analysis in the Kou watershed

in Geocarto International (2012)

The Kou watershed is characterized by important water resources used for drinking, agriculture (especially in the important irrigated areas), industry and the preservation of aquatic fauna and flora. For ... [more ▼]

The Kou watershed is characterized by important water resources used for drinking, agriculture (especially in the important irrigated areas), industry and the preservation of aquatic fauna and flora. For several decades there has been increasing pressure on the Kou’s water resources, partly because of the expansion of the irrigated agricultural areas. This study was conducted to examine this issue, focusing on one specific irrigated area. In order to monitor the expansion of irrigated areas in developing countries, a low-cost remote sensing method based on Landsat images and aerial photographs was developed. The method is based on maximum-likelihood classifications, followed by backward and forward change detection analysis requiring agronomic expertise. Using pixel trajectory analysis, the method connects all pixels to their consecutive states in order to correct their current states. The study showed that the irrigated area has expanded by almost 80% over 20 years, with most of this expansion occurring in the past 10 years. The approach, if validated, could be used to obtain information on past occupation in the rural irrigated areas for which there is no archived data. [less ▲]

Monitoring the ionospheric activity using GNSS. From dual frequency GPS to multi-constellation multi-frequency GNSS

Scientific conference (2012, June 20)

Monitoring the Ionospheric TEC using GPS Data

in Kersley, Len (Ed.) Proceedings of Beacon Satellite Symposium '94 (1994)

Monitoring the zinc affinity of the metallo-beta-lactamase CphA by automated nanoESI-MS

in Journal of the American Society for Mass Spectrometry (2006), 17(2), 180-188

Metallo-beta-lactamases are zinc containing enzymes that are able to hydrolyze and inactivate beta-lactam antibiotics. The subclass B2 enzyme CphA of Aeromonas hydrophila is a unique metallo-p-lactamase ... [more ▼]

Metallo-beta-lactamases are zinc containing enzymes that are able to hydrolyze and inactivate beta-lactam antibiotics. The subclass B2 enzyme CphA of Aeromonas hydrophila is a unique metallo-p-lactamase because it degrades only carbapenems efficiently and is only active when it has one zinc ion bound. A zinc titration experiment was used to study the zinc affinity of the wild-type and of several mutant CphA enzymes. It shows that a second Zn2+ is also bound at high ion concentrations. All samples were analyzed using mass spectrometry in combination with an automated nanoESI source. The metal-free enzyme has a bimodal charge distribution indicative of two conformational states. A completely folded enzyme is detected when the apo-enzyme has bound the first zinc. Intensity ratios of the different enzyme forms were used to deduce the zinc affinities. CphA enzymes mutated in metal ligands show decreased zinc affinity compared to wild-type, especially D120 mutants. [less ▲]