RESUMO
Background: A molecular biomarker of physiologic age, as opposed to chronologic age, is needed in clinical medicine. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGsn) and 8-oxo-7, 8-dihydroguanosine (8-oxoGsn) are two promising aging biomarkers. Methods: A total of 1,228 healthy Chinese residents (613 males and 615 females) 2-90 years of age were randomly selected. Spot urine samples were collected, and the concentrations of 8-oxodGsn and 8-oxoGsn were measured using ultra-high-performance liquid chromatography with a triple quadrupole mass spectrometer (UPLC-MS/MS). Method validation, including accuracy, precision, linearity and quantification limit, was performed. The relationship between oxidized guanosine and age/gender was evaluated. Results: 8-oxodGsn and 8-oxoGsn were eluted at 1.61 and 1.30 min, respectively. The calibration curve was linear in the range of 0.2-500 ng/ml for both analytes. The lowest limit of quantification (LLOQ) was 0.2 ng/ml for 8-oxodGsn and 0.1 ng/ml for 8-oxoGsn. There was an age-dependent increase in the biomarkers from the 21- to 30-year-old group to the 81- to 90-year-old group in both genders. In the subjects older than 61 years of age, the levels of 8-oxodGsn as well as 8-oxoGsn in urine were much higher in females than in males. The content of 8-oxoGsn correlated more closely with age and was higher (approximately 2-fold) than that of 8-oxodGsn for a given individual. Conclusions: 8-oxodGsn and 8-oxoGsn can be easily measured by UPLC-MS/MS. Urinary 8-oxoGsn may be a potential biomarker to determine a person's physiologic age and identify individuals at high risk of developing age-associated disease.
RESUMO
OBJECTIVES: To explore the diagnostic value of immunofixation electrophoresis and Kappa/Lambda (KAP/LAM) ratio in multiple myeloma patients with renal injury. METHODS: The serum of 822 patients of renal disease were collected for the examnation of immunofixation electrophoresis, KAP/LAM ratio, serum immunoglobulin levels and renal function, including serum urea nitrogen (BUN), serum creatinine (Crea), cystatin C (Cys-C) and estimated glomerular filtration rate (eGFR). To analyze the diagnostic value of immunofixation and KAP/LAM ratio in the differentiation of renal injury of multiple myeloma from primary renal injury diseases. RESULTS: M protein was observed in 75 patients (9.1%). The ratio of each type was IgG 49.3%(37/75), IgA 34.7%(26/75), IgM 5.3%(4/75) and LAM 10.7%(8/75). There was significant difference of KAP/LAM ratio between M protein group and non-M protein group. The KAP/LAM ratio was significant higher in KAP group, compared to non-M protein group. Reverse result was obtained in LAM group. There were higher Crea level and lower eGFR value in pure LAM light chain group, compared with IgG, IgA and IgM groups. CONCLUSIONS: Immunofixation electrophoresis and KAP/LAM ratio may play an important role in the diagnosis of multiple myeloma patients with renal injury, so could be early screening markers.
