Objective To investigate the impacts of cytokines （interleukin-4，IL-4；tumor necrosis factor-α，TNF-α） and medications of bronchial asthma （dexamethasone，aminophylline，salbutamol） on the activity of histamine N-methyltransferase（HMT） in tracheal epithelial cells.Methods BEAS-2B bronchial epithelial cells were cultured and treated with different concentration of TNF-α, IL-4, dexamethasone, salbutamol and aminophylline respectively. The activity of HMT in BEAS-2B cells was determined by high performance liquid chromatography.Results The activity of HMT in tracheal epithelial cells was (50±7) pmol?min-1?mg pro-1.TNF-α and IL-4 lowered the activity of HMT significantly at the concentration equal to or higher than 1 ng/mL and 5 ng/mL respectively，and reached the maximum inhibitory effect at the level of 10 ng/mL.Dexamethasone and aminophylline could ameliorate distinctly the inhibitory effect of TNF-α on the activity of HMT, while salbutamol had no significant inhibitory effect.Conclusions TNF-α and IL-4 exert the lowering effect on the activity of HMT，which would be one important cause of airway hyperreactivity.Glucocorticoids and theophyllines are administered to treat asthma partly due to its relieving mechanism of TNF-α negative effects on HMT.
Objective To improve the knowledge of lung injury induced by rituximab. Methods Clinical data of 5 lymphoma patients with lung injury caused by rituximab chemotherapy were analyzed. Results Five patients received chemotherapy including rituximab, and had fever, cough and dyspnea after 3 to 5 chemotherapy cycles. Chest CT showed bilateral diffuse interstitial infiltrates. All 5 cases experienced hypoxemia or respiratory failure. Clinical symptoms were improved 3 to 5 days after the treatment of glucocorticoids, and pulmonary lesions were significantly alleviated 1 to 2 weeks after the treatment. According to the literature, the incidence rate of lung injury caused by rituximab was 0. 03% to 4. 9%, which has increased recently. Conclusions With the comprehensive application of rituximab, lung injury caused by this drug is not rare. The good prognosis depends on early diagnosis and treatment by further recognition of the side effect of rituximab.
Objective To study the influence of different mechanical environments on repair cartilage defect with marrow mesenchymal stem cells as seed cells. Methods The rabbit marrow mesenchymal stem cells were isolated and cultured. The cartilage defects were repaired by autologous tissue engineered cartilage with the marrow mesenchymal stem cells as seed cells. Fifteen rabbits with cartilage defect were divided into 3 groups: dislocation group with cell-free scaffold(controlgroup), dislocation group with cartilaginous construct and normal mechanical environment group with cartilaginous construct. The repaired tissue was harvested and examined 6 weeks postoperatively. Results The repair tissue in normal mechanical environment group with cartilaginous construct showed cartilage-like tissue in superficial layer and subchondral bone tissue in deep layer 6 weeks postoperatively. The defect was filled with bone tissue in dislocation group with cartilaginous construct 6 weeks postoperatively. The surrounding normal cartilage tissue showed vascular invasion from subchondral area and the concomitant thinningof the normal cartilage layer. The cartilaginous construct left in the femoral trochlea groove formed hyaline cartilage-like tissue. The defect was repaired byfibrous tissue in control group. Conclusion The repaired tissue by tissue engineered cartilage with marrow mesenchymal stem cells as seed cells showed the best result in normal mechanical environment group, which indicates that it will be essential for the formation and maintenance of tissue engineered cartilage to keep the normal mechanical stress stimulus.
OBJECTIVE To study the feasibility of constructing tissue engineered cartilage by differentiated rabbit bone marrow mesenchymal stem cells(MSC) cultured in vitro and in vivo. METHODS The MSC were isolated from the nucleated cells fraction of autologous bone marrow by density gradient centrifuge, and then induced into chondrogenic differentiation by adding dexamethasone, transforming growth factor-beta 1 (TGF-beta 1) and ascorbic acid in vitro. After 3 weeks, some cells turned to round shape and secreted metachromatic matrix. The cartilaginoid grafts composed of chondrogenic MSC. Bovine type I collagen and human fibrin were cultured within the chondrogenic medium for 2 weeks in vitro or transplanted subcutaneously adjacent to the knee joint for 3 weeks in vivo. RESULTS The most cells in the grafts were degenerated and disappeared after cultured in vitro. But the residual cells were survival and secreted metachromatic staining proteoglycan with toluidine blue, which was characteristic cartilage matrix. The grafts developed into matured cartilage tissue assessed by histological examination after 3 weeks of transplantation in vivo. CONCLUSION MSC can be used as functional cells to constructing tissue engineered cartilage.