High-performance liquid chromatographic assay with fluorescence detection for the determination of cephaeline and emetine in human plasma and urine

Tuning a 96-well microtiter plate fluorescence-based assay to identify AGE inhibitors in crude plant extracts

Advanced glycation end-products (AGEs) are involved in the pathogenesis of numerous diseases. Among them, cellular accumulation of AGEs contributes to vascular complications in diabetes. Besides using drugs to lower blood sugar, a balanced diet and the intake of herbal products potentially limiting AGE formation could be considered beneficial for patients’ health. The current paper presents a simple and cheap high-throughput screening (HTS) assay based on AGE fluorescence and suitable for plant extract screening. We have already implemented an HTS assay based on vesperlysines-like fluorescing AGEs quickly (24 h) formed from BSA and ribose under physiological conditions. However, interference was noted when fluorescent compounds and/or complex mixtures were tested. To overcome these problems and apply this HTS assay to plant extracts, we developed a technique for systematic quantification of both vesperlysines (λ_exc 370 nm; λ_em 440 nm) and pentosidine-like (λ_exc 335 nm; λ_em 385 nm) AGEs. In a batch of medicinal and food plant extracts, hits were selected as soon as fluorescence decreased under a fixed threshold for at least one wavelength. Hits revealed during this study appeared to contain well-known and powerful anti-AGE substances, thus demonstrating the suitability of this assay for screening crude extracts (0.1 mg/mL). Finally, quercetin was found to be a more powerful reference compound than aminoguanidine in such assay.

Munchausen syndrome and factitious disorder: the role of the laboratory in its detection and diagnosis

The term Munchausen syndrome is used to describe the patient who chronically fabricates or induces illness with the sole intention of assuming the patient role. Such persons often have a close association with the medical profession and thus use their knowledge to falsify symptoms and laboratory specimens to mimic disease. Cases of factitious disease have appeared in the literature originating from all medical specialties, and include such rare disorders as phaeochromocytoma and Bartter's syndrome. The laboratory can play a key role in the detection and diagnosis of factitious disorders. Indeed discrepant biochemistry results may provide the first clue to the diagnosis. Laboratory staff should be particularly aware of highly variable test results and extreme abnormalities that are not consistent with the wider biochemical profile, suggesting sample tampering. Factitious disorder should also be included in the clinician's differential diagnosis when disease presentation is unusual or an underlying cause cannot be found. Investigation to exclude or confirm factitious disorder at an early stage can prevent unnecessary testing in the search for increasingly rare diseases. Appropriate analyses may include screening tests for the detection of surreptitious drug administration or replication of a fabricated sample to confirm the method used. In all cases close communication between the clinician and laboratory is essential. This will ensure that appropriate tests are conducted particularly with regard to time critical and repeat tests.