PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9730654

Scintigraphic imaging of renal function.

A M Peters
View original source ↗Export metadata ↓

Abstract

Scintigraphic imaging of renal physiology can be achieved by gamma camera planar imaging, single photon emission computerised tomography (SPECT) or positron emission tomography (PET). Physiological information about the kidney usually requires dynamic imaging, although for some applications imaging may be static. Individual kidney renal blood flow can be measured from dynamic gamma camera imaging, although with PET it is possible to measure regional renal perfusion. Measurement of individual kidney glomerular filtration rate (GFR) is performed routinely with Tc-99m-diethylene triamine pentaacetic acid (DTPA), but information about GFR on a regional basis, and measurement of regional filtration fraction, require PET. Manoeuvres which interfere with renal physiology, such as captopril renography, may also yield useful diagnostic information.

Explore related subjects

CaptoprilGamma CamerasGlomerular Filtration RateHippuratesHumansKidneyKidney DiseasesKidney Function TestsRenal CirculationTechnetium Tc 99m PentetateTomography, Emission-ComputedTomography, Emission-Computed, Single-PhotonJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A M Peters. Scintigraphic imaging of renal function.. https://doi.org/10.1159/000020547

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Effective controlled release of captopril by silylation of mesoporous MCM-41.

The release of the water-soluble drug Captopril is controlled by tailoring the surface properties of mesoporous silica via stepwise silylation. The degree of silylation is manipulated by adjusting the initial concentration of silylanizing reagent (trimethylchlorosilane, TMCS). The silylanized and drug-loaded samples are characterized by powder X-ray diffraction, Fourier transform IR spectroscopy, N2 adsorption and desorption, 29Si cross-polarization magic angle spinning NMR spectroscopy, and transmission electron microscopy. The drug-loading amount is correlated to the Brunauer-Emmett-Teller surface area and surface hydrophilicity/hydrophobicity of the mesoporous silica material, while drug release profiles can be controlled by tailoring the surface properties and pore size.

Captopril↗
PubMed2005

A selective and rapid method for the quantification of captopril in human plasma using liquid chromatography/selected reaction monitoring mass spectrometry.

A specific hyphenated high performance liquid chromatography-mass spectrometric (LC-MS/MS) assay was developed for the determination of captopril in plasma. The drug was extracted from plasma using liquid-liquid extraction with a mixture of diethylether:dichloromethane. After the addition of the internal standard, samples were applied to a prepacked C8 Waters Symmetry column. The ion trap MS/MS detector was equipped with electrospray ionization (ESI) source operating in the positive ion mode. Drug determination was accomplished monitoring captopril at molecular ion m/z 218 and MS/MS (daughter) at m/z 171.6. The method was applied to captopril determination in human plasma after the administration of captopril 50 mg tablets to healthy volunteers who have participated in a pharmacokinetic study. The method was proved to be specific and precise by testing six different plasma batches. Linearity was established for the range of concentrations 25-3000 ng/ml with a regression factor of 0.9995. Intra-day accuracy ranged from 90.16 to 96.18%, while the intra-day precision ranged from 2.60 to 9.66% at the concentrations of 75, 1440 and 2500 ng/ml. Inter-day precision of the method ranged from 5.04 to 10.10%. This validated method of analysis was successfully applied to human plasma analyses after the administration of a single dose of 50 mg captopril tablets to healthy volunteers.

Captopril↗
PubMed2005

Direct calculation of interconversion barriers in dynamic chromatography and electrophoresis: Isomerization of captopril.

Dynamic capillary electrophoresis (DCE) and direct calculation of the rate constants of isomerization has been applied to determine the cis-trans isomerization barriers of the angiotensin-converting enzyme inhibitor captopril. The separation of the rotational cis-trans isomeric drug has been performed in an aqueous 50 mM borate buffer at pH 9.3. Interconversion profiles featuring plateau formation, peak-broadening, and peak coalescence were observed. To determine the rate constants of the forward and backward reaction (k(cis-->trans) and k(trans-->cis)) of the isomerization process in dynamic capillary electrophoresis, a novel straightforward calculation method using the experimental parameters plateau height, h(plateau), peak width at half height w(h), the total migration times of the cis-trans isomers t(R) and the electroosmotic break-through time t(0) as well as the peak ratio of the cis-trans isomers is presented for the first time. From temperature dependent measurements the rate constants k(cis-->trans) and k(trans-->cis) and the kinetic activation parameters DeltaG( not equal), DeltaH( not equal), and DeltaS( not equal) of the cis-trans isomerization of captopril were obtained. From the activation parameters the isomerization barriers of captopril at 37 degrees C under basic conditions were calculated to be DeltaG( not equal) (cis-->trans) = 90.3 kJ.mol(-1)and DeltaG( not equal) (trans-->cis) = 90.0 kJ.mol(-1*).

Captopril↗