Simultaneous determination of genistein and its four phase II metabolites in blood by a sensitive and robust UPLC–MS/MS method: Application to an oral bioavailability study of genistein in mice

The purpose of this research was to develop a sensitive and reproducible UPLC–MS/MS method to simultaneously quantify genistein, genistein-7-O-glucuronide (G-7-G), genistein-4′-O-glucuronide (G-4′-G), genistein-4′-O-sulfate (G-4′-S) and genistein-7-O-sulfate (G-7-S) in mouse blood samples. After the method was fully validated over a wide linear range, it was applied to quantify the levels of genistein and its metabolites in a mouse bioavailability study. The linear response range was 19.5–10,000 nM for genistein, 12.5–3200 nM for G-7-G, 20–1280 nM for G-4′-G, 1.95–2000 nM for G-4′-S, and 1.56–3200 nM for G-7-S, respectively. The lower limit of quantification (LLOQ) was 4.88, 6.25, 5, 0.98 and 0.78 nM for genistein, G-7-G, G-4′-G, G-4′-S and G-7-S, respectively. Only 20 μl mouse blood sample from i.v. and p.o. administration were needed for analysis because of the high sensitivity of the method. The intra- and inter-day variance is less than 15% and accuracy is within 85–115%. The analysis was finished within 4.5 min. The applicability of this assay was demonstrated and successfully applied for bioavailability study in FVB mouse after i.v. and p.o. administration of 20 mg/kg of genistein, and its oral bioavailability was ∼23.4%.     

Clinical cavitation and radiographic lesion depth in proximal surfaces in an Indian population

Objectives. To assess the relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces of permanent posterior teeth in an Indian population. This study also assessed the clinical feasibility of applying ’western guidelines’ to this population from the developing world. Materials and methods. Relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces in an Indian population was assessed. Proximal surfaces (n = 126) without restorations were examined on bitewing radiographs in patients with suspected caries and lesion depth was recorded by five observers. The radiographic scoring scale was 0 = sound; 1 = lesion in enamel; 2 = lesion in outer 1/3 of dentine and 3 = lesion in inner 2/3 of dentine. Orthodontic separators were placed interdentally and removed after 3 days, where surfaces were recorded as cavitated (yes/no) by two clinical validators (gold standard). Results. Enamel lesions were cavitated in 25.6–38.3%, outer dentinal lesions were cavitated in 83.3–100% and inner dentinal lesions were cavitated in 96.4–100% depending on observer and validator. On applying ‘western guidelines’ for treatment decision to the radiographic findings of lesion depth, 80–100% of the lesions observed in outer dentine would lead to a false (non-operative) treatment decision. Conclusions. Radiographic shallow carious lesions were often cavitated in this population. The threshold for cavitation in this study population is suggested to be set between enamel and outer dentine in contrast to western guidelines.