Die quantitative Analyse von Markerproteinen im Urin Quantitative analysis of marker proteins in urine

Die Analyse von spezifischen Proteinen im zweiten Morgenurin, bezogen auf den Kreatiningehalt der Probe, erlaubt heute nicht nur den Nachweis oder den Ausschluss von Nierenerkrankungen, sondern darüber hinaus auch die Differenzierung und Verlaufskontrolle von Nephropathien. Störungen lassen sich aufgrund ihres Markerproteinprofils in solche mit hauptsächlich glomerulärem oder tubulärem Anteil und zusätzlich in weitere Untergruppen einteilen. Im Zusammenhang mit den Teststreifenresultaten kann die Quelle einer Blutung mit spezifischen Quotienten näher eingegrenzt und Kontaminationen können von tatsächlichen renalen Proteinurien unterschieden werden. Eine Plausibilitätsprüfung und Interpretation der erhaltenen Ergebnisse ist unbedingt erforderlich. Da eineVielzahl von Regeln überprüft werden muss, ist eine Berechnung und Darstellung der Ergebnisse nur mit Hilfe von wissensbasierten Systemen in Kombination mit einer grafischen Befunddarstellung sinnvol

Low biochemical nutritional parameters in acutely ill hospitalized elderly patients with and without stage III to IV pressure ulcers

Background and aims: Pressure ulcers are associated with impaired nutritional status in acutely ill elderly patients. The objective of this study was to establish whether a difference exists between biochemical nutritional parameters in acutely ill elderly with stage III to IV pressure ulcers and a group of acutely ill elderly with no pressure ulcers. Methods: In a retrospective study we compared 8 biochemical nutritional markers in a group of 22 acutely ill elderly patients consecutively admitted to the geriatric ward who had stage III to IV pressure ulcers (PU group) in addition to their acute illness with a control group of 40 acutely ill elderly patients with no pressure ulcers (NPU group). Results: The PU group compared with the NPU group had significantly lower (p<0.0001) values of albumin, transferrin, hemoglobin, cholesterol, iron, and zinc (p<0.0059). Total lymphocyte count was slightly, but not significantly lower in the PU group. In contrast, C-Reactive Protein levels were significantly higher (p<0.0001) in the PU group compared with the NPU group, indicating a more severe illness in the presence of additional pressure ulcers. Conclusions: In this study, serum levels of biochemical nutritional parameters in acutely ill elderly patients with stage III to IV pressure ulcers are lower than those of acutely ill elderly subjects with no pressure ulcers, indicating a worse nutritional status of the PU patients. These findings, while not documenting a causal relationship, suggest the need for routine nutritional assessment and support in older patients, especially those with pressure ulcer

Development and Characterization of an Enzymatic Method for the Rapid Determination of Gamma Hydroxybutyric Acid

Gamma hydroxybutyric acid (GHB) is a regulated therapeutic drug, which naturally occurs in mammalian brain tissues as an intermediate of the GABA (gamma aminobutyric acid) neurotransmitter metabolism. The increasing misuse of GHB as a narcotic or abusing drug in recent years calls for the development of a simple and rapid screening method as an alternative to the currently available, technically demanding diagnostic methods. We have developed a rapid enzymatic assay based on the GHB dehydrogenase of Ralstonia eutropha. The enzyme is expressed as a recombinant protein in Escherichia coli and characterized in terms of reaction mechanism and kinetic parameters for the catalysis of conversion of GHB into succinic semialdehyde (SSA). The concomitant NADH production enables spectrophotometric monitoring of the reaction and the quantification of GHB in physiological fluids depending on initial velocities. We have tested a panel of twelve serum and urine samples containing GHB concentrations from 0.0 to 2.1 mmol/L. GHB dehydrogenase activity obeys a non classical bi bi ping pong mechanism exhibiting substrate inhibition by NAD+. With an optimal NAD+ concentration of 3.7 mmol/L in the reaction, the enzyme yields a KM of 1.0 mmol/L for GHB and a Vmax of 3.37 mmol/min/mg. The assay shows a linear standard curve from 0.1 to at least 1 mmol/L of GHB. Spiking experiments result in mean recoveries of 92% for urine and 114% for serum, respectively. The comparison to an ion chromatographic reference method exhibits a mean difference of 10% divergence from the target values in urine and 9% in serum, respectively

Undetectable phenytoin serum levels by an automated particle-enhanced turbidimetric inhibition immunoassay in a patient with monoclonal IgM lambda

Phenytoin is a drug used for the treatment of different types of seizures. Its variable pharmacokinetics, mainly a consequence of variable bioavailability, saturable protein binding and saturable hepatic metabolism, predisposes the drug to therapeutic drug monitoring. Several methods to analyze the drug in serum exist with immunoassays being the method of choice for routine measurements. Immunoassays are specific and sensitive, but cross-reactivity, possibly leading to erroneous serum levels, is a concern. We report a patient with falsely undetectable phenytoin serum levels

An automated screening method for drugs and toxic compounds in human serum and urine using liquid chromatography-tandem mass spectrometry

A fully automated screening using liquid chromatography-mass spectrometric method applying data-dependent acquisition was developed to identify toxicologically relevant substances in serum and urine. A library including more than 405 spectra of about 365 compounds (main drugs and important metabolites) was established. An easy to use program was created to automate and accelerate library search. Drugs were identified based on their relative retention times, molecular ions and fragment ions. Limits of detection were tested with 100 of the 365 compounds the majority of these were lower than 100?g/l (67%). The developed LC-MS-MS system seems to be a valuable alternative to other general unknown screening methods allowing fast and specific identification of drugs in serum and urine samples