朝鲜淫羊藿酸性多糖的理化特性及对HepG2细胞脂质堆积的改善作用＊

目的 对比研究朝鲜淫羊藿酸性多糖酯化还原前后的理化特性，并探讨其改善油酸诱导的肝癌HepG2细胞脂质堆积活性的差异。方法 采用高效凝胶渗透色谱法测定朝鲜淫羊藿酸性多糖（EFPA）的均一性和分子量，高效液相色谱法测定EFPA和酯化还原后朝鲜淫羊藿酸性多糖（EFPA-R）的单糖组成；采用油酸（OA）处理HepG2细胞诱导建立脂质蓄积模型，不同浓度EFPA与EFPA-R（10、30、100、300 μg·mL^-1）分别和OA共同作用于细胞24 h，采用CCK-8试剂盒测定细胞存活率，油红O染色观察细胞内脂滴蓄积情况，并采用试剂盒测定细胞内总胆固醇（TC）、甘油三酯（TG）含量。结果 EFPA为成分均一的多糖组分，分子量为125.8 kDa，由甘露糖、葡萄糖、半乳糖、葡萄糖醛酸和阿拉伯糖组成，摩尔比为1.7∶7.4∶1.4∶1.8∶1.0，葡萄糖占比最大，EFPA-R由甘露糖、葡萄糖、半乳糖和阿拉伯糖组成，摩尔比为0.8∶10.6∶2.1∶1.0；在10-300 μg·mL^-1范围内，EFPA和EFPA-R对HepG2细胞的抑制作用较弱，作为给药浓度；与空白组相比，模型组细胞中TC、TG含量显著升高（P < 0.01），细胞内红色脂滴显著增多，与模型组相比，EFPA可显著降低细胞中TC、TG含量（P < 0.01），明显减少细胞内红色脂滴（P < 0.05或P < 0.01），EFPA-R干预后细胞则无明显变化。结论 EFPA可明显改善HepG2细胞脂质堆积情况，且呈现剂量依赖性，而半乳糖醛酸（GalA）的存在可能是其抑制HepG2细胞脂质蓄积的关键因素。     

Antipsychotics with inverse agonist activity at the dopamine D3 receptor

Summary In NG 108-15 cells expressing the recombinant human D₃ receptor, dopamine agonists enhance [³H]thymidine incorporation and decrease cAMP accumulation. In these cells, but not in wild type cells, haloperidol, fluphenazine, and various other antipsychotics inhibited basal [³H]thymidine incorporation in a concentration-dependent manner. In contrast, other dopamine antagonists such as nafadotride or (+)AJ 76, two D₃-preferring antagonists, were without effect. The concentration-response curve of haloperidol was shifted to the right in presence of nafadotride, with a potency compatible with its nanomolar apparent affinity as neutral antagonist. Pertussis toxin treatment abolished or markedly reduced the responses to haloperidol or fluphenazine. In contrast, no significant enhancement of cAMP accumulation could be observed, under the influence of haloperidol or eticlopride. These data indicate that some dopamine antagonists behave as inverse agonists, and thus appear to inhibit an agonist-independent activity of the D₃ receptor on [³H]thymidine incorporation pathway, but not on the cAMP pathway.     

论现阶段医疗保险个人帐户存在的必要性

[目的]探讨医疗保险个人账户是否有存在的必要性。[方法]将方案设计的初衷与实际运行相比较分析。[结果]医疗保险个人帐户约束和积累作用发挥得不理想，在一定程度上抑制了老年人和陵性病患者的医疗需要。从我国国民的心理承受力和国民素质及解决人口老龄化时支付危机等方面的考虑，笔者认为在现阶段有其存在的必要。[结论]应采取扩大覆盖对象，调整使用范围，取消退休人员个人账户，加强对供方的管理以及其它配套措施来进一步完善。     

乳腺癌改良根治术后皮下积液的预防措施

目的 探讨乳腺癌术后皮下积液的防治方法。方法 回顾北京友谊医院普外科2002年1月～2004年12月收治的女性乳腺癌患者312例。比较皮下引流管接持续高负压吸引组（A组）与持续低负压引流组（B组），乳腺癌改良根治术后皮下积液的发生率。结果 A组160例患者拔管前合计引流量220～350ml，平均270ml。35例发生皮下积液，积液发生率为21．8％。同时伴皮瓣坏死5例。B组152例患者拔管前合计引流量160～250ml，平均180ml。17例发生皮下积液，积液发生率为11．2％。皮瓣坏死3例。B组与A组比较皮下积液发生率有显著性差异（P=0．011）。结论 乳腺癌改良根治术后引流管接持续低负压吸引有助于减少皮下积液的发生率。     

Accumulation of carbon disulphide metabolites

Summary Biological monitoring for carbon disulphide (CS₂) exposure performed using the iodine-azide test (IAT) and 2-thiothiazolidine-4-carboxylic acid (TTCA) test in urinalysis of workers with high exposure to CS₂ (112–142 mg/m³, n = 34), workers with low exposure (4–7 mg/m³, n = 16), and non-exposed university workers (n =10). Pre-shift and post-shift urine specimens were collected on three consecutive days in the exposed and for only one day in the non-exposed. According to the findings the specificity and the sensitivity seem to be low for the IAT and high for the TTCA test. Contrary to a previous report all pre-shift urine samples showed negative IATs. The TTCA test was positive in pre-shift urine even after 32 to 63.5 h without exposure, and values tended to increase during consecutive days of exposure in highly exposed workers.The possible health implications of these findings should be further investigated.     

Clinical experience with minimal flow xenon anesthesia

Xenon is a more potent anesthetic than nitrous oxide, and gives more profound analgesia. This investigation was performed to assess the potential of xenon for becoming an anesthetic inspite of its high manufacturing cost. Seven ASA I—-II patients undergoing cholecystectomy (n = 4), hernia repair (n = 2), or mammoplasty (n=l) were studied. Denitrogenation by 15–20 min of oxygen breathing under propofol anesthesia was followed by fentanyl–supplemented xenon anesthesia administered via an automatic minimal flow system which held the oxygen concentration at 30%. Xenon anesthesia lasted 76–228 min and 8–14 1 of xenon (ATPD) was used, of which 5.6–8.1 1 was expended during the first 15 min. Anesthesia appeared to be satisfactory, and the patients woke up rapidly after xenon was discontinued. The automatic system made minimal flow xenon anesthesia easy to administer, but nitrogen accumulation is still a problem. Assuming a xenon price of 10 US $ per litre, the average cost for xenon was about 65 US $ for the first 15 min and then about 25 USS for each subsequent hour of anesthesia.     

Intrathecal vincristine: a fatal chemotherapeutic error with devastating central nervous system effects

Summary The devastating neuropathological changes wrought by the intrathecal administration of vincristine are reported, with a detailed account of the widespread lesions in the brain and spinal cord, found in post-mortem light- and electron-microscope studies.     

Transfer of clonidine and dexmedetomidine across the isolated perfused human placenta

Background: The placental transfer of the a₂ receptor agonist clonidine, earlier used as an adjuvant in obstetric epidural analgesia, was compared with the transfer of the newer and more %-selective agonist dexmedetomidine.
Methods: Term placentas were obtained immediately after delivery with maternal consent and a 2-hour recycling perfusion of a single placental cotyledon was performed. Disappearance from the maternal circulation, accumulation in placental tissue and appearance in the fetal circulation of clonidine or dexmedetomidine with the reference compound antipyrine were followed in 4 experiments for both drugs.
Results: At 2 hours the percent dexmedetomidine found in the fetal circulation was 12.5 (SD 5.1)%, while 48.1 (SD 20.3)% was found in the perfused placental cotyledon. A higher mean clonidine than dexmedetomidine concentration was achieved in the fetal circulation (1.90 vs. 0.56 nmol/l, P <0.05). At 2 hours the percent clonidine found in the fetal circulation was 22.1 (SD 2.4)% ( P <0.05), while 11.3 (SD 3.3)% ( P <0.05) was re tained in the perfused placental cotyledon. The transfer indexes, describing maternal-to-fetal transfer of dexmedetomidine and clonidine normalized with the transfer of antipyrine, were 0.88 (SD 0.07) and 1.04 (SD 0.08) respectively ( P <0.05).
Conclusions: Dexmedetomidine disappeared faster than clonidine from the maternal circulation, while even less dexmedetomidine was transported into the fetal circulation. This was due to its greater placental tissue retention, the basis for which probably is the higher lipophilicity of dexmedetomidine.     

Damage mechanics and load failure of fiber-reinforced composite fixed partial dentures

OBJECTIVES: Damage mechanics has been defined as the study of the initiation (initial failure) and accumulation of damage to and including rupture (final failure). This study was designed to evaluate the effect of increasing fiber-reinforced composite (FRC) substructure within a standardized fixed partial denture (FPD) model on the failure performance, in terms of damage mechanics. METHODS: The two FRC restorative systems, Targis/Vectris (TV) (Ivoclar Vivadent) and EverStick (ES) (Stick Tech with Gradia, GC Corp.), were used to restore the molar FPD model (1.5 mm axial and 2.0 mm occlusal reduction). Templates were used to standardize substructure designs with 0, 18, 43, and 66% cross-sectional FRC volume fraction (V(FRC)) of fiber substructure. Specimens (n = 5) were homogenized at 29 points and stored for 1 week at 37 degrees C in distilled water. Specimens were luted with calcium hydroxide, then statically loaded until failure. Initial failure (IF), final failure (FF) and the mode of failure were recorded. RESULTS: The lowest mean load to initial failure was 530 N (TV 18%) and the highest was 1208 N (ES 66%). Linear regression analysis calculated the Pearson's correlation coefficient (r) for the interactions between V(FRC) and IF (ES: r = 0.7879, TV: r = 0.6184), V(FRC) and FF (ES: r = 0.912, TV: r = 0.8152), and between IF and FF (ES: r = 0.892, TV: r = 0.7237). Unreinforced specimens universally fractured instantaneously. SIGNIFICANCE: The highest loads to initial and final failure were yielded by specimens with the highest cross-sectional V(FRC).