Background and purpose:Regulation of MMR activity under hypoxia may play an important role in genetic instability of cancer,but the mechanism is still unclear.We investigated the expression of DNA mismatch repair genes MLH1 and MSH2 in human SCLC cell line H446 under hypoxic condition and explore the role of promoter methylation of genes in hypoxia.Methods:RT-PCR and Western blot were applied to detect MLH1 and MSH2 expression in human SCLC cell line H446 at the mRNA and the protein level,respectively,under either hypoxic condition or after 5-Aza-CdR treatment.Meanwhile,methylation-specific PCR(MSP)was used to determine promoter methylation of MLH1 and MSH2.Results:The expression of MLH1 and MSH2 in H446 cells significantly decreased both at the mRNA and the protein level under hypoxic condition.5-Aza-CdR treatment led to the restoration of MLH1 and MSH2 expression,while,both MLH1 and MSH2 were down-regulated again after removing 5-Aza-CdR.Conclusions:The promoter methylation of MLH1 and MSH2 may play an important role in its defective expression in H446 cells under hypoxic condition.And 5-Aza-CdR could restore MLH1 and MSH2 expression.

Objective To establish a multidrug-resistant cell subline NCI-H446/CDDP of human small cell lung cancer and characterize its biological properties. Methods The cell subline NCI-H446/CDDP was derived from human small cell lung cancer cell line NCI-H446 by exposing it to high concentration first followed by being cultured with gradually increasing dose of cisplatin, which used to be the first-line chemotherapeutic drug for lung cancer. The cell growth curve and the doubling time were determined by cell counting. The chemosensitivities of NCI-H446/CDDP and NCI-H446 to cisplatin, hydroxycamptothecine, vincristin, 5-fluorouracil and topotecan were tested and IC 50 measured by MTT. Changes in cellular morphology and ultrastructure were observed under inverted-microscope, scanning electron microscope and transmission electron microscope, respectively. Results Multidrug-resistant cell subline (NCI-H446/CDDP) of human small cell lung cancer was established successfully after culturing NCI-H446 in a high concentration of cisplatin first, followed by subjecting it to increasing concentrations of CDDP until they could stably grow in the culture medium containing 0.5?g/mL CDDP. The rate of cell proliferation of NCI-H446/CDDP was similar to that of NCI-H446, but the number of the former cells exhibiting S phase increased (20.24% vs 18.42% P

Objective To investigate the role of methylated DNA mismatch repair gene MLH1 and MSH2 in the acquired multidrug-resistance of human small cell lung cancer cells H446.Methods The reverse transcription polymerase chain reaction(RT-PCR)and Western blot were applied to measure MLH1 and MSH2 mRNA and protein expressions of the multidrug-resistant cells H446/DDP and its parental cells H446.The promoter methylation status of the genes was assessed by methylation-specific PCR(MSP).Results The expressions of MLH1 and MSH2 significantly decreased both in mRNA level and protein level.Promoter methylation of MLH1 was observed in H446/DDP cells but not in H446 cells.Promoter semi-methylation of MSH2 in H446 cells was transformed to methylation in H446/DDP cells.Conclusion The downregulation of DNA mismatch repair gene MLH1 and MSH2 induced by its promoter methylation may play an important role in the acquired multidrug resistance of human small cell lung cancer.

Objective The filum terminale(FT)plays an important role in the pathophysiology of tethered cord syndrome(TCS).The study on morphology and structure of fetus FF can provide reference standard for diagnosis of TCS.Methods Ten fresh human aborted fetuses had their fila measured and removed.Transversal and longitudi nal sections of the middle,and distal thirds of FF were submitted to light microscopy analysis with four different techniques.Results The bulk of the Frr is composed of 1～5μm thick spring like longitudinal bundles of colla gen separated by 5～30μm layer intervals and 1～5μm intervals in the layer,although a small quantity of eapillar ies and other elements may be present.Collagen bundles can also be found between layers and bundles.Abundant longitudinally oriented elastic fibers ale found inside or between collagen bundles.Conclusion A complex tridi mensional structure composed by ordered arrangement of spring like fibers and small quantity of capillaries should e licit considerable elastic properties to the FI".Tts alternation of structure and element maybe involved in TCS closely.

Objective To observe the effects of acupuncture on blood lipids of hyperlipidemia mice, and explore the mechanism of acupuncture against endothelial dysfunction. Methods 40 ApoE (-/- ) mice were randomly divided into control group (C), acupuncture at non-acupoint group (D), acupuncture at acupoint group (E), and simvastatin group (F) with 10 cases in each group. After 8 weeks, total cholesterol (TC), the plasma angiotensin II (Ang II), endothelin-1 (ET-1) and nitric oxide (NO) were measured with enzyme-linked immuno sorbent assay (ELISA). The mice myocardial angiotensin II type 1 receptor (AT1R), and endothelin-1 type A receptor (ETAR) protein were detected with Western blotting. Results The blood lipid, the content of plasma Ang II and ET-1, and the level of AT1R and ETAR in the heart tissue were significantly lower, and the content of NO was significantly higher in groups E and F than in group C (P<0.05). Conclusion Acupuncture can inhibit the level of blood lipids in ApoE(-/-) mice, reduce the levels of Ang II and ET-1, increase the level of NO in peripheral blood, and inhibit the expression of AT1R, ETAR in heart tissue.