应用四唑盐比色法对5种骨水泥的细胞毒性的测试

0　引言　应用细胞培养法对牙科材料的生物相容性进行评价是一种简便、有效、经济的方法 .近年来 ,国内外有许多学者报道用 MTT检测细胞活性 ,并认为用 MTT法可以代替活细胞计数、同位素标记进行细胞毒性试验 .我们应用 MTT法对 5种骨水泥的细胞毒性进行了评价 ,并对有关问题进行了讨论 .1　材料和方法1.1　测试材料　 1号 :生物水泥 ,2号 :羟基磷灰石人工骨 ,3号 :氰基丙烯酸酯骨水泥 1号 (自制 ) ,4号 :氰基丙烯酸酯骨水泥 2号 (自制 ) ,5号 :氰基丙烯酸酯骨水泥 3号 (自制 ) .阴性对照采用珊瑚 ,阳性对照采用聚氯乙烯 .1.2　实验步骤…     

膝关节周围骨肿瘤手术的肢体康复

0　引言　膝关节周围是骨原发恶性肿瘤的好发部位 .病变组织广泛侵袭 ,切除肿瘤造成骨与软组织缺损 ,各种重建方法都需最大限度地保留膝关节功能 .如何采取早期系统的康复治疗 ,是临床骨肿瘤保肢手术的重要内容 .1　对象和方法　 1992 - 0 5 / 1999- 0 3,膝关节周围恶性骨肿瘤患者 6 4例接受保肢手术治疗 .男 38例 ,女 2 6例 ;骨肉瘤 5 2例 ,恶性骨巨细胞瘤 5例 ,尤文瘤 3例 ,母细胞瘤 2例 ,原发神经外胚层肿瘤 2例 .手术方式 :异体半关节移植术 37例 ;异体骨段移植术 16例 ;复合异体骨段的人工全膝关节表面置换术3例 ,动力旋转铰链式人工全…     

陵水暗罗活性成分研究

从陵水暗罗(polyalthia nemoralis A.etDC)根的乙醇提取物中分离得到五个化合物。经光谱(UV,IR,¹H-NMR,¹³C-NMR,DEPT和MS)解析和化学反应,分别鉴定为暗罗素(zincpolyanemine,PN1),2-巯基吡啶-N-氧化物铜盐(PN₂),β-谷甾醇(PN₃),β-谷甾醇-β-D-吡喃葡萄糖甙(PN₄)和2-巯基吡啶-N-氧化物-2-S-β-D-吡喃葡萄糖甙(PN₅),其中PN₅为新化合物,PN2为新天然产物。PN1和PN2有较强抗疟、防霉杀菌作用。PN5的抗疟、防霉试验尚在进行中。     

Four categories of gamma-globin gene triplications: DNA sequence comparison of low G gamma and high G gamma triplications

The human fetal gamma chains are produced by closely linked G gamma and A gamma genes, and unequal crossing over between them leads to gamma gene deletions and triplications. Nine gamma gene triplications from seven ethnic groups were analyzed for G gamma and hemoglobin F (Hb F) values of heterozygotes and for the presence of polymorphic XmnI restriction sites 5' to the gamma genes. Four categories of triplication were found: I had low G gamma and low Hb F values and lacked XmnI sites 5' to the three gamma genes [---]. II had high G gamma and slightly elevated Hb F values but was also [---]. III was similar to II, except that XmnI was [+--]. IV had very high G gamma and slightly elevated Hb F values, and XmnI was [++-]. One case each of triplications I and IV were cloned into Charon 35. For both, the two 5' gamma gene code for G gamma chain, while the 3' gamma gene codes for A gamma chain. DNA sequencing showed that the unequal crossover occurred between 472 and 398 base pairs (bp) 5' to the gamma gene Cap sites (- 472 and -398) for the type IV triplication and between -271 and codon 136 for the type I triplication. In addition, type I had a 4-bp deletion of AGCA from -225 to -222. The high G gamma values of the type IV triplication are explained by its -G gamma-G gamma-A gamma-gene arrangement and the XmnI sites 5' to the G gamma genes. We hypothesize that the low G gamma value of the type I triplication, which is also -G gamma-G gamma-A gamma-, is due to inactivation of the middle G gamma gene by the AGCA deletion at -225 to -222.     

Tegillarca granosa extract Haishengsu (HSS) suppresses expression of mdr1, BCR/ABL and sorcin in drug-resistant K562/ADM tumors in mice

PurposeTo evaluate the effect of Haishengsu (HSS), a protein extract from Tegillarca granosa, on multidrug-resistance genes mdr1, BCR/ABL and sorcin in transplanted tumors.Material/MethodsMice were inoculated subcutaneously with a drug resistant leukemia cell line K562/ADM. Tumor-bearing animals were divided into control, adriamycin, HSS and combination therapy (adriamycin plus HSS) groups. Flow cytometry was used to detect apoptosis of tumor cells, and RT-PCR was used to evaluate the expression of mdr1, BCR/ABL and sorcin.ResultsThe apoptosis rate in the high (71.8%), medium (72.3%) and low doses HSS group (72.4%) was higher than in control (1.2%, p<0.01), adriamycin (34.4%, p<0.05) or combination therapy group (46.4%, p<0.05). The mean optical density of mdr1, BCR/ABL and sorcin in HSS groups was lower than in control, adriamycin and combination therapy group (p<0.01). The optical density of the three genes in high HSS group was lower than in medium and low HSS group (p<0.01).ConclusionsHaishengsu promotes apoptosis of drug-resistant K562/ADM tumors in mice in a dose-dependent manner. The pro-apoptotic effect of Haishengsu may be related to a reduced expression of multidrug-resistance genes mdr1, BCR/ABL and sorcin.     

Wear Resistance Improvement of Cemented Tungsten Carbide Deep-Hole Drills after Ion Implantation

The paper is dedicated to the life prolongation of the tools designed for deep-hole drilling. Among available methods, an ion implantation process was used to improve the durability of tungsten carbide (WC)-Co guide pads. Nitrogen fluencies of 3 × 10¹⁷ cm⁻², 4 × 10¹⁷ cm⁻² and 5 × 10¹⁷ cm⁻² were applied, and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses, X-ray photoelectron spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements were performed for both nonimplanted and implanted tools. The durability tests of nonimplanted and the modified tools were performed in industrial conditions. The durability of implanted guide pads was above 2.5 times greater than nonimplanted ones in the best case, presumably due to the presence of a carbon-rich layer and extremely hard tungsten nitrides. The achieved effect may be attributed to the dissociation of tungsten carbide phase and to the lubrication effect. The latter was due to the presence of pure carbon layer with a thickness of a few dozen nanometers. Notably, this layer was formed at a temperature of 200 °C, much smaller than in previously reported research, which makes the findings even more valuable from economic and environmental perspectives.     

Rapid prenatal diagnosis of beta thalassemia using DNA amplification and nonradioactive probes

We used in vitro DNA amplification by the polymerase chain reaction and nonradioactive probes for prenatal diagnosis of beta thalassemia in Chinese from the Guangdong province. Exact molecular diagnoses were made in all 20 fetuses studied over a 6-month period. We conclude that this method of prenatal diagnosis for beta thalassemia is a viable approach in many parts of the world where this disease is common.