A predominant apoptotic death pathway of neuronal PC12 cells induced by activated microglia is displaced by a non-apoptotic death pathway following blockage of caspase-3-dependent cascade.

Activated microglia have been implicated in the regulation of neuronal cell death. However, the biochemical mechanism for neuronal death triggered by activated microglia is still unclear. When treated with activated microglia, neuronal PC12 cells undergo apoptosis accompanied by caspase-3-like protease activation and DNA fragmentation. Apoptotic bodies formed were subsequently phagocytosed by neighboring activated microglia. Pretreatment of the cells with the caspase-3-like protease inhibitor N-acetyl-Asp-Glu-Val-Asp-aldehyde did not reverse this cell death. Although Bcl-2 overexpression in the cells caused the inhibition of caspase-3-like protease activity and DNA fragmentation and the effective interference of apoptosis induced by deprivation of trophic factors, it could not suppress the activated microglia-induced neuronal death. At the electron microscopic level, degenerating cells with high levels of Bcl-2 were characterized by slightly condensed chromatins forming irregular-shaped masses, severely disintegrated perikarya, and marked vacuolation. Various protease inhibitors tested did not inhibit this cell death, whereas the radical oxygen species scavenger N-acetyl-L-cysteine significantly suppressed this death. Altogether, our study provides an alternative death pathway for the activated microglia-induced neuronal death by blockage of the caspase-3 protease cascade.     

关于延胡索学名的商榷

延胡索最早(公元1000年左右)在我国作为植物药物记载于宋《开宝本草》,迄今长期沿用这一名称,专指浙江主产的栽培种。延胡索别名"元胡",为著名行气止痛中药,在医药界从来不存在名称混乱问题。     

氨茶碱及硝苯吡啶治疗高原肺水肿效果观察

目的:评价氨茶碱及硝苯吡啶对高原肺水肿的疗效.方法:采用右心漂浮导管方法,观察了静脉推注氨茶碱及舌下含服硝苯吡啶对患者血流动力学及动脉血气等方面的影响.结果:氨茶碱能降低患者的肺动脉压和肺血管阻力,提高患者的心输出量及动脉血氧饱和度,用药前后体循环压及心率未见明显变化.硝苯吡啶含服也能降低肺动脉压和肺血管阻力,虽能降低体循环压但幅度较小,但用药前后心输出量、心率及动脉血气饱和度未见明显变化.结论:氨茶碱及硝苯吡啶均有急性降低高原肺水肿患者肺动脉高压的作用,但二者相比,氨茶碱降低肺动脉压效果明显优于硝苯吡啶.     

Molecular cloning and characterization of a 2-deoxystreptamine biosynthetic gene cluster in gentamicin-producing Micromonospora echinospora ATCC15835

The organization of the 2-deoxystreptamine (DOS) biosynthetic gene cluster of Micromonospora echinospora has been determined. Sequencing of a 14.04 kb-region revealed twelve open reading frames (ORFs): four putative DOS biosynthetic genes (gtmA, B, C, and D), five amino sugars biosynthetic genes (gtmE, G, H, I, and gacB), two aminoglycoside resistance genes (gtmF and J) as well as a hypothetical ORF (gacA). One of the putative DOS biosynthetic genes, gtmA, was expressed in Escherichia coli, and the purified protein was shown to convert glucose-6-phosphate (G-6-P) to 2-deoxy-scyllo-inosose (DOI), a key step in DOS biosynthesis. In addition gtmJ was expressed in Streptomyces lividans and shown to confer gentamicin resistance. Thus gtmA and gtmJ are implicated in the biosynthesis of gentamicin and in resistance to it, respectively.     

Orthopedic intrusion of premaxilla with distraction devices before alveolar bone grafting in patients with bilateral cleft lip and palate

Surgical repositioning of the downward displaced premaxilla in bilateral cleft lip and palate patients remains a controversial and perplexing issue because of its detrimental effects on the growth of the premaxilla. The purpose of this prospective clinical study was to introduce and evaluate the treatment results of an innovative technique for nonsurgically intruding the downward displaced premaxilla. Eight consecutive cases of bilateral cleft lip and palate at the age of mixed dentition were included for the correction of their premaxillary deformities. A pair of intraoral tooth-borne distraction devices was used for the orthopedic intrusion. Serial lateral and posteroanterior cephalometric radiographs were taken periodically for evaluating the growth of the premaxilla 1 year before the intrusion, changes during the intrusion, and growth/relapse up to 1 year after the intrusion. There was no overgrowth of the premaxilla or overeruption of the maxillary incisors during the 1-year observing period before the orthopedic intrusion. The treatment results revealed that the downward displaced premaxillae were all corrected within 1 month. Cephalometrically, 46 percent of the correction resulted from a true orthopedic intrusion and another 54 percent from a dentoalveolar effect in which the maxillary incisors were intruded and the premaxillary dentoalveolus was shortened. The cephalometric evaluations also implied that what occurred during the orthopedic intrusion was mostly the sutural contraction osteogenesis/osteolysis in the vomeropremaxillary suture combined with slightly mechanical upward displacement of the vomeronasal septum complex and nasal bones. The orthopedic intrusion of the premaxilla with distraction devices is an effective nonsurgical method for correcting the downward displaced premaxilla before alveolar bone grafting in patients with bilateral cleft lip and palate, and the results remained stable after 1 year.     

Oncogenic ras mediates apoptosis in response to protein kinase C inhibition through the generation of reactive oxygen species

Ras is a well established modulator of apoptosis. Suppression of protein kinase C (PKC) activity can selectively induce apoptosis in cells expressing a constitutively activated Ras protein. We wished to determine whether reactive oxygen species serve as an effector of Ras-mediated apoptosis. Ras-transformed NIH/3T3 cells contained higher basal levels of intracellular H(2)O(2) compared with normal NIH/3T3 cells, and PKC inhibition up-regulated ROS to 5-fold greater levels in Ras-transformed cells than in normal cells. Treatment with N-acetyl-l-cysteine reduced both the basal and inducible levels of intracellular H(2)O(2) in NIH/3T3-Ras cells and antagonized the induction of apoptosis by PKC inhibition. Culturing NIH/3T3-Ras cells in low oxygen conditions, which prevents ROS generation, also inhibited the apoptotic response to PKC inhibition. These results suggest that reactive oxygen species are necessary as downstream effectors of the Ras-mediated apoptotic response to PKC inhibition. However, the generation of ROS alone is not sufficient to induce apoptosis in Ras-transformed cells because inhibition of cell cycle progression prevented the induction of apoptosis in NIH/3T3-Ras cells without inhibiting the generation of intracellular H(2)O(2) observed after PKC inhibition. These findings suggest that continued cell cycle progression of Ras-transformed cells during PKC inhibition is also necessary for the induction of apoptosis.