Mechanism of bilirubin diglucuronide formation in intact rats

A B S T R A C T Although it is well established that bilirubin monoglucuronide is formed in the liver from bilirubin by a microsomal bilirubin uridine diphosphate (UDP)-glucuronosyltransferase, the subcellular site of conversion of monoglucuronide to diglucuronide and the molecular mechanism involved in diglucuronide synthesis have not been identified. Based on in vitro studies, it has been proposed that two fundamentally different enzyme systems may be involved in diglucuronide synthesis in rat liver: (a) a microsomal UDP-glucuronosyltransferase system requiring UDPglucuronic acid as sugar donor or (b) a transglucuronidation mechanism that involves transfer ofa glucuronosyl residue from one monoglucuronide molecule to another, catalyzed by a liver plasma membrane enzyme. To clarify the mechanism by which bilirubin monoglucuronide is converted in vivo to diglucuronide, three different experimental approaches were used. First, normal rats were injected with either equal amounts of bilirubin

Multicentre evaluation of the Boehringer Mannheim/Hitachi 917 analysis system

The new selective access analysis system BM/Hitachi 917 was evaluated in an international multicentre study, mainly according to the ECCLS protocol for the evaluation of analysers in clinical chemistry. Forty-three different analytes, covering 56 different methods enzymes, substrates, electrolytes, specific proteins, drugs and urine applications were tested in seven European clinical chemistry laboratories. Additionally, the practicability of the BM/ Hitachi 917 was tested according to a standardized questionnaire. Within-run CVs (median of 3 days) for enzymes, substrates and electrolytes were <2% except for creatine-kinase MB isoform and lipase at low concentration. For proteins, drugs and urine analytes the within-run CVs were < 4% except for digoxin and albumin in urine. Between-day median CVs were generally < 3% for enzymes, substrates and electrolytes, and < 6% for proteins, drugs and urine analytes, except for lipase, creatine kinase and MB isoform, D-dimer, glycosylated haemoglobin, rheumatoid factors, digoxin, digitoxin, theophylline and albumin in urine in some materials. Linearity was found according to the test specifications or better and there were no relevant effects seen in drift and carry-over testing. The interference results clearly show that also for the BM/Hitachi 917 interference exists sometimes, as could be expected because of the chemistries applied. It is a situation that can be found in equivalent analysers as well. The accuracy is acceptable regarding a 95–105% recovery in standard reference material, with the exception of the creatinine Jaffé method. Most of the 160 method comparisons showed acceptable agreement according to our criteria: enzymes, substrates, urine analytes deviation of slope ± 5%, electrolytes ± 3%, and proteins and drugs ± 10%. The assessment of practicability for 14 groups of attributes resulted in a grading of one–three scores better for the BM/Hitachi 917 than the present laboratory situation. In conclusion, the results of the study showed good analytical performance and confirmed the usefulness of the system as a consolidated workstation in medium-sized to large clinical chemistry laboratories

Assay of mannose-6-phosphatase in untreated and detergent-disrupted rat-liver microsomes for assessment of integrity of microsomal preparations

Este artículo presenta un análisis comparativo de las diferentes metodologías y métodos existentes en el estado del arte orientados al diseño e implementación de ontologías. El trabajo incluye además algunos aspectos como la especificación de lenguajes y herramientas de implementación de las propias ontologáas. Finalmente, los resultados se resumen en un caso de aplicación de un dominio específico formulado en el área de las artes plásticas

Laboratory medicine: challenges and opportunities

Technologic innovations have substantially improved the productivity of clinical laboratories, but the services provided by clinical laboratories are increasingly becoming commoditized. We reflect on how current developments may affect the future of laboratory medicine and how to deal with these changes. We argue that to be prepared for the future, clinical laboratories should enhance efficiency and reduce costs by forming alliances and networks; consolidating, integrating, or outsourcing; and more importantly, create additional value by providing knowledge services related to in vitro diagnostics.status: publishe

Can heparin plasma be used instead of serum for nephelometric analysis of serum proteins?

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