RESUMO
RATIONALE & OBJECTIVES: Estimated glomerular filtration rate (eGFR) using creatinine and cystatin C (eGFRcr-cys) may be less accurate compared to measured GFR (mGFR) in China than in North America, Europe, and Australia due to variation across regions in their non-GFR determinants. The non-GFR determinants of ß2-microglobulin (B2M) and ß-trace protein (BTP) differ from those of creatinine and cystatin C. Thus, the average eGFR using all 4 markers (eGFRavg) could be more accurate than eGFRcr-cys in China. STUDY DESIGN: Diagnostic test study. SETTING & PARTICIPANTS: 1,066 participants in Shanghai and Beijing with creatinine and cystatin C and 666 participants with all 4 filtration markers. TESTS COMPARED: Index tests were previously developed equations for eGFR using creatinine, cystatin C, B2M, and BTP and combinations. The reference test was mGFR using plasma clearance of iohexol. We compared the performance of eGFRavg to eGFRcr-cys using the proportion of participants with errors in eGFR >30% of mGFR (1 - P30) and root mean square error (RMSE) of the regression of eGFR on mGFR on the logarithmic scale. We also compared classification and reclassification of mGFR categories using eGFRavg compared to eGFRcr-cys. OUTCOMES: Accuracy was significantly better for eGFRavg (1 - P30 of 10.4% and RMSE of 0.214) compared to eGFRcr-cys (1 - P30 of 13.8% and RMSE of 0.232; P = 0.004 and P = 0.006, respectively). However, improvements in accuracy did not generally translate into significant improvement in classification or reclassification of mGFR categories. LIMITATIONS: Study population may not be generalizable to clinical settings other than large urban medical centers in China. CONCLUSIONS: A panel of endogenous filtration markers including B2M and BTP in addition to creatinine and cystatin C may improve GFR estimation in China. Further study is necessary to determine whether GFR estimation using B2M and BTP can be improved and whether these improvements lead to useful clinical applications.
RESUMO
Objective To study the distribution of rifampin(RFP), isoniazid(INH) and pyrazi-namide(PZA) in the focus of spinal tuberculosis in order to provide the regimen of chemotherapy and surgi-cal treatment of spinal tuberculosis. Methods Twenty-four patients with spinal tuberculosis were divided into sclerotic group or non-sclerotic group according to the radiographic features of lesion. All patients re-ceived chemotherapy with 2SHRZ/2.5 H2R2Z2 for a duration of 4.5 months. 4 weeks after chemotherapy, all patients underwent surgery and specimen of serum, ilium and vertebral tissues including sclerotic wall, sub-normal osseous tissue, focus inside sclerotic wall (sclerotic group) and destructive focus, peripheral subnor-mal osseous tissue (non-sclerotic group) were obtained during operation at 120-130 and 180-190 minutes after oral intake in the morning respectively. The levels of 3 drugs in the specimen were measured using HPLC method. Results 1) The concentration levels of INH and PZA in serum were similar to the data in the literature, but the level of RFP was only 75% of that in the literature. The levels of 3 drugs in osseous tissue were significantly less than those of blood. 2) Concentrations of isoniazid and rifampicin in self-control ilium and sub-normal bone tissue were within or exceeded the bactericidal concentration values,and pyrazi-namide was five fold of it's minimal inhibitory concentration (MIC) in acid cellular condition. There were no significant differences between sub-normal bone and self-control ilium of 3 drugs concentration. 3) Concen-tration of 3 drugs in sclerotic bone wall were approximate to MIC respectively in sclerotic group and much lower than sub-normal bone. There was no drug distribution of focus inside sclerotic bone wall. 4) RFP and PZA in focus of non-sclerotic group corresponded to the levels of MIC respectively, though much lower than in other parts of vertebral tissues, but the INH in focus was of bactericidal level. Conclusion The sclerotic bone of affected vertebra plays an important role to block the drug's penetration into tuberculosis focus.
