This is an experimental study on the distribution of antituberculosis drugs such as rifampin, isoniazid, and pyrazinamide in pathologic vertebrae of spinal tuberculosis in order to provide the regimen of chemotherapy and surgical treatment of spinal tuberculosis. The distribution of antituberculosis drugs in pathologic vertebral tissues matters greatly to the clinical effect of spinal tuberculosis' treatment. However, few pharmacokinetic studies and clinical reports about the concentrations of antituberculosis drugs in vertebral foci have been published so far. Twenty-four patients with spinal tuberculosis were divided into sclerotic group (n = 15) or non-sclerotic group (n = 9) according to radiographic features of lesion. All patients received chemotherapy with 2HRZ/2Á5H 2 R 2 Z 2 for a duration of 4.5 months. Four weeks after chemotherapy all patients underwent surgery and the specimen of serum, ilium, and pathologic vertebral tissues, including sclerotic wall, subnormal osseous tissue, and foci were obtained during operation in 120-130 and 180-190 min after oral intake in the morning, respectively. The levels of three drugs in the specimen were measured using HPLC method. The concentration levels of isoniazid, rifampin and pyrazinamide varied greatly in different tissues of spinal tuberculosis, of which the bactericidal concentration values of isoniazid and rifampin and fivefold minimal inhibitory concentration (MICs) of pyrazinamide were found in subnormal vertebral bone and self-contrast ilium, the MICs of all drugs were found in sclerotic wall outside foci, and undetected level was found in foci inside the sclerotic wall. To patients without vertebral sclerotic wall around the foci, the isoniazid in foci was of bactericidal level and rifampin and pyrazinamide in foci corresponded to the MICs respectively. The sclerotic bone of affected vertebra plays an important role in blocking the antituberculosis drug's penetration into tuberculosis focus.
Due to the heterogeneity of cancer cell populations, the traditional evaluation approach of cell viability based on the cell counting assay is quite inaccurate for the dose−response test of anticancer drugs, cell toxicology assays, and other biochemical stimulations. In this paper, an evaluation approach of cell viability based on the cell detachment assay in a single-channel integrated microfluidic chip is proposed to improve the accuracy of cell viability assessment. The electrodes are coated by fibronectin for specific cell adhesion, and it is biologically significant to study the cell detachment assay in vitro. The maximum number of cells that can be detected by this sensor is about 10 5 cells (overgrowing), while the minimum is about 100 cells. This method is calibrated with the half-maximal inhibitory concentration assay, and the results show that the cell viability calculated by adhesion strength is more accurate than that evaluated using the cell counting assay. Meanwhile, the shear rate is transformed into shear stress for the comparability among the results in other papers. The most sensitive frequency is also determined as 1 kHz according to normalized impedance. Besides, the impedance of cell adhesion affected by different shear stresses is monitored to study the optimized plan for long-term culture of cells in the integrated microfluidic chip prepared for the cell detachment assay. Adhesion strength τ 25 , which is the magnitude of shear stress needed to detach 75% of cell population, is introduced to describe the cell adhesion forces. It is calculated and normalized based on the cell detachment assay to evaluate cell viability. The relative errors of the cell detachment method compared with those of the cell counting method decrease by 0.637 (0% FBS), 0.586 (0.5% FBS), and 0.342 (2% FBS).
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