免疫磁珠法分离白血病转基因小鼠骨髓造血干细胞

本文分离转基因小鼠骨髓造血干细胞。运用针对小鼠干细胞表面特异表达的干细胞抗原 1(stemcellantigen 1,Sca 1)的单克隆抗体和包被于磁颗粒表面的第二抗体 ,采用磁吸附细胞分选方法 (MACS )分离小鼠骨髓造血干细胞 ,用流式细胞术 (FACS )检测MACS分离后骨髓细胞中干细胞 (Sca 1阳性细胞 )比例 ,监测细胞分选效果。结果显示MACS分离后骨髓细胞中Sca 1阳性细胞所占比例达 85 %以上 ,涂片观察发现细胞组成和细胞形态学特征与FACS所得结果一致。MACS可以从转基因小鼠全骨髓细胞中分离出Sca 1阳性的骨髓造血干细胞 ,细胞纯度可达 85 %以上。     

A multiple-pathway model for the diffusion of drugs in skin

A mathematical model for the diffusion of drugs in skin is presented.The penetration of the drug by both transcellular and intercellularpathways, as well as its interchange between these pathways,is considered. A pharmacologically motivated asymptotic limitis identified and analysed to obtain, in particular, an analyticalexpression for the flux of drug to the blood at steady state.Relevant model data is discussed, and some numerical resultsare also presented.     

口腔修复陶瓷材料的磨损性能北大核心

背景:陶瓷材料因具有优良的机械性能、与口腔组织良好的生物相容性及高度美观性广泛应用于口腔修复领域,良好的磨损性能对修复体临床应用有重要意义。目的:综述口腔修复陶瓷材料磨损性能机制及临床研究,以期为临床选择适宜的陶瓷材料提供思路。方法:应用计算机在PubMed和Web of Science数据库检索在2016年1月至2021年4月期间涉及口腔修复陶瓷材料磨损性能的相关研究。英文检索词为“dental ceramic material,wear property”,最终共纳入36篇文献进行分析。结果与结论:①全瓷材料自身耐磨性均高于树脂陶瓷复合材料,全瓷材料中氧化锆陶瓷磨损性能最佳,美学性能较弱。②玻璃陶瓷中氧化锆加强型硅酸锂玻璃陶瓷磨损性能较好,但应用时间较短,长期疗效还有待更多的研究证实。③树脂陶瓷复合材料中树脂纳米陶瓷材料磨损性能优于聚合物渗透陶瓷。④在后牙区全冠修复可选择氧化锆陶瓷,前牙区全冠修复可以根据患者的美学需求选择高透性氧化锆陶瓷或玻璃陶瓷。⑤贴面、嵌体和高嵌体修复可选择长石瓷、玻璃陶瓷和树脂陶瓷复合材料,但树脂陶瓷复合材料耐磨性差,需避免用于高应力承载区。⑥对牙本质暴露、氟斑牙和牙齿酸蚀症患者可考虑树脂纳米陶瓷材料,但这类患者适宜的陶瓷材料相关研究较少。⑦表面粗糙度对陶瓷材料的磨损性能有显著影响,临床口腔修复应用中采用良好的抛光表面可提高陶瓷材料磨损性能,而且对修复体进行定期复查也至关重要。     

用于牙科复合树脂的具有固位力外形的无机填料的研究

本文介绍了一类微细的复合式无机填料。由于具有特殊的表面结构，这类填料与复合树脂中的树脂基质之间有良好的结合力，因此称之为“具有固位力外形的无机填料”。用此类填料配制的试验性复合树脂，不仅其磨耗性能有明显的改善，而且其它机械性能也有不同程度的提高。     

Increased seminal plasma lead levels adversely affect the fertility potential of sperm in IVF

BACKGROUND: Lead remains in high levels in the environment and is known to reduce fertility in animal models, but a direct link between lead exposures and human infertility has not yet been established. METHODS: In a prospective, double-blind study of the metal ion levels and sperm function, semen was obtained from partners of 140 consecutive women undergoing their first IVF cycle. Lead in seminal plasma was determined by atomic absorption spectroscopy. Motile sperm populations were assessed for surface receptors for mannose binding, and the ability to undergo premature ('spontaneous'), and free mannose-induced acrosome reactions. Fertile donor (n = 9) sperm were exposed to exogenous lead during capacitating incubations and then assessed for mannose receptor expression and acrosome loss. RESULTS: Lead levels were negatively correlated with IVF rates. Lead levels were negatively correlated to two of the three sperm function biomarkers (mannose receptors, mannose-induced acrosome reactions). Lead levels positively correlated with the spontaneous acrosome reaction. These findings were mimicked by in-vitro exposure of fertile donor sperm to lead. CONCLUSIONS: Multiple sperm parameters are affected as lead levels rise. Increased lead levels may contribute to the production of unexplained male infertility.     

Vaginal absorption of oestradiol and progesterone

The vaginal absorption of micronized oestradiol/progesterone from a hydrophilic matrix system was investigated before and after 10 days of treatment in 7 post-menopausal women with an average age of 56.1 yr.

Oestradiol and progesterone levels were measured on days 1 and 11 before administration and 0.5, 1, 2, 3, 4, 6, 8, 12, and 24 h afterwards by radioimmunoassay.

Peak values were seen 6–12 h after administration. This finding differs from those of other investigations. Sex hormone binding globulin (SHBG) and androgen concentrations were unchanged after 10 days of treatment.     

Lymphatic absorption and metabolism of orally administered testosterone undecanoate in man

Summary [³H]-testosterone undecanoate ([³H]TU) was administered orally to 4 patients with a thoracic duct catheter after neck dissection surgery.Appearance of radioactivity in lymph, plasma and urine was measured at different times. Metabolites of TU in these fluids were investigated. Peak levels of radioactivity appeared simultaneously in lymph and plasma (2.5–5 h after administration) while the excretion in urine was highest approximately 2 h after the plasma and lymph peak. The main compounds appearing in the lymph were TU and 5-dihydrotestosterone undecanoate (5-DHTU), but 5-DHTU could not be detected. In plasma almost all metabolites were probably conjugated.During the first 24 h approximately 40% of the administered radioactivity was excreted in the urine. The total amount of radioactivity excreted in the urine during the first week was 45–48%. The predominant urinary metabolites were testosterone- and androsterone-glucuronide.The results indicate that TU is metabolized partly in the intestinal wall. The remaining TU and newlyformed 5-DHTU, at least partly, are absorbed via the lymphatic system.     

血液灌流对硫线磷和硫酸阿托品的吸附作用

Objective To study on adsorption effect of cadusafos and atropine sulfate by hemoperfusion.Method Hemoperfusions were performed for sheep blood samples with cadusafos and atropineby through imitated extracorporeal closed circulating perfusion apparatus.Residual cadusafos was determined by gas chromatography and residual atropine was determined by high performance liquid chromatography.Result Dose of adsorption agent was 0.5,1.0 and 1.5 g,respectively.Two hours after hemoperfusion with membrane coated activated charcoal,clearance rate of cadusafos in 3 groups all exceeded 90%.and clearance rate of atropine sulfate was 61.9%,84.9%,88.9%,respectively.One and a half hours after hemoperfusion with HA230 absorption resin,clearance rate of eadusafos in 3 groups all exceeded 90%,and clearance rate of atropine sulfate was 88.0%,97.2%,98.4%,respectively.Three hours after hemoperfusion with membrane coated activated charcoal,The concentration ratio of cadusafos and atropine sulfate in blood promoted to 10.1 times,and the ratio was 6.7 times after hemoperfusion with HA230 absorption resin.Conclusion It suggested that cadusafos were mostly removed from blood after 1.5～2.0hours hemoperfusion with membrane activated charcoal or HA230 absorption resin.The concentration ratio of cadusafos and atropine sulfate in blood will increased after hemoperfusion.     

Characterization of a monoclonal anti-Bw4 antibody (Tü109): Evidence for similar epitopes on the Bw4 and Bw6 antigens

The production and serologic, as well as immunochemical properties of a cytotoxic murine IgG monoclonal antibody (Tü109) that precipitates HLA-class I molecules, are described. In the microcytotoxicity assay Tü109 supernatant was demonstrated on a panel of 424 HLA-ABC, -DR, -DQ, -MT typed normal Caucasian blood donors to define an epitope on HLA-B locus molecules in great association with the supertypic specificity Bw4. Reactivity of supernatant showed MHC linked inheritance of the Tü109 determinant and discriminated the HLA-Bw4/Bw6 associated HLA-B locus split antigens. Weak or lack of binding on lymphocytes from some HLA-Bw4 heterozygous individuals, particularly typing for HLA-Bw44, appeared to be due to qualitative and/or quantitative variations of HLA-B locus molecules on the cell surface. With Tü109 ascites fluid, however, extra-reactivity on all HLA-Bw6⁺ cells was demonstrated. Preferential binding of supernatant to HLA-Bw4, but reactivity of ascites fluid with HLA-Bw6⁺ molecules in addition, was furthermore confirmed by IEF analysis of antigens immunoprecipitated with Tü109 from cell lysates. Thus the antibody may help to analyze the evolutionary relationship of the diallelic specificities Bw4 and Bw6.     

Ultrastructural and biochemical studies on the intestinal absorption of a medium-chain triglyceride (MCT), tricaprylin

The intestinal absorption of a medium-chain triglyceride (MCT) was studied by electron microscopy and biochemical analysis. In jejunal absorptive cells of rats fed tricaprylin, the smooth endoplasmic reticulum in the apical cytoplasm appeared to increase in number and contained one or two particles about 40–80 nm in diameter that were less electron dense and similar in size and profile to very low density lipoprotein. Similar particles were also observed packed in the dilated Golgi sacs and in the extended intercellular spaces. These particles were remarkably increased in number as compared with those in fasted rats. Biochemical analysis of lymph from the main intestinal lymph duct showed that caprylate was apparently demonstrated only in the lymph of rats given tricaprylin at the maximum rate 3h after oral administration. The study strongly suggests that medium-chain triglyceride is at least in part transported via lacteal, possibly in the form of very low density lipoprotein.