三种抗癫痫药对癫痫患者脑电图的背景影响比较研究

目的：研究对比三种抗癫痫药（苯妥因钠、丙戊酸钠、卡马西平）对癫痫患者脑电图的背景影响。方法：选取我院于2009年3月至2011年2月收治的60例癫痫患者,随机分为苯妥因钠（PHT）、卡马西平（CBZ）和丙戊酸钠（SVP）组各20例,动态观察各组患者于治疗期间痫样波放电的频度和EEG背景的变化。结果：EEG痫样波放电的抑制率以SVP最为明显,而CBZ在EEG背景活动影响方面均比其他两组显著。结论：三种药物对癫痫波放电的抑制顺序是SVP〉PHT〉CBZ,SVP组明显优于其他两组。     

家庭氧疗配合呼吸操治疗慢性阻塞性肺疾病患者的疗效

目的：观察长期家庭氧疗配合呼吸操治疗慢性阻塞性肺疾病（COPD）的临床效果。、方法：选择本院收治的COPD患者80例,随机分为研究组和对照组,各40例,两组均给予常规治疗,研究组同时由医务人员指导给予家庭氧疗和呼吸操训练,随访1年．观察两组治疗前、治疗后6个月和1年肺功能,应用StGeorge’S呼吸问卷（SGRQ）评价生存质量、结果：研究组1年内急性发作1次5人,2次2人,3次及以上1人,对照组1年内急性发作1次9人,2次7人,3次及以上4人（P〈0．05）;研究组治疗后6个月、1年用力肺活量（FVC）、第1秒用力呼气容积（FEVl）和FEVl／FVC均明显升高（P〈0．05）,对照组治疗后6个月、1年FVC、FEVI／FVC与治疗前比较无统计学差异（P〉0．05）;研究组治疗后6个月、1年SGRQ明显降低（P〈0．05）,对照组治疗后6个月、1年SGRQ与治疗前比较无统计学差异（P〉0．05）．结论：家庭氧疗配合呼吸操能明显改善COPD患者肺功能,延缓患者肺功能恶化,提高患者生存质量。     

A widespread plant-fungal-bacterial symbiosis promotes plant biodiversity,plant nutrition and seedling recruitment

Highly diverse microbial assemblages colonize plant roots. It is still poorly understood whether different members of this root microbiome act synergistically by supplying different services (for example, different limiting nutrients) to plants and plant communities. In order to test this, we manipulated the presence of two widespread plant root symbionts, arbuscular mycorrhizal fungi and nitrogen-fixing rhizobia bacteria in model grassland communities established in axenic microcosms. Here, we demonstrate that both symbionts complement each other resulting in increased plant diversity, enhanced seedling recruitment and improved nutrient acquisition compared with a single symbiont situation. Legume seedlings obtained up to 15-fold higher productivity if they formed an association with both symbionts, opposed to productivity they reached with only one symbiont. Our results reveal the importance of functional diversity of symbionts and demonstrate that different members of the root microbiome can complement each other in acquiring different limiting nutrients and in driving important ecosystem functions.     

Molecular coevolution among cryptically simple expansion segments of eukaryotic 26S/28S rRNAs

The set of "expansion segments" of any eukaryotic 26S/28S ribosomal RNA (rRNA) gene is responsible for the bulk of the difference in length between the prokaryotic 23S rRNA gene and the eukaryotic 26S/28S rRNA gene. The expansion segments are also responsible for interspecific fluctuations in length during eukaryotic evolution. They show a consistent bias in base composition in any species; for example, they are AT rich in Drosophila melanogaster and GC rich in vertebrate species. Dot-matrix comparisons of sets of expansion segments reveal high similarities between members of a set within any 28S rRNA gene of a species, in contrast to the little or spurious similarity that exists between sets of expansion segments from distantly related species. Similarities among members of a set of expansion segments within any 28S rRNA gene cannot be accounted for by their base-compositional bias alone. In contrast, no significant similarity exists within a set of "core" segments (regions between expansion segments) of any 28S rRNA gene, although core segments are conserved between species. The set of expansion segments of a 26S/28S gene is coevolving as a unit in each species, at the same time as the family of 28S rRNA genes, as a whole, is undergoing continual homogenization, making all sets of expansion segments from all ribosomal DNA (rDNA) arrays in a species similar in sequence. Analysis of DNA simplicity of 26S/28S rRNA genes shows a direct correlation between significantly high relative simplicity factors (RSFs) and sequence similarity among a set of expansion segments. A similar correlation exists between RSF values, overall rDNA lengths, and the lengths of individual expansion segments. Such correlations suggest that most length fluctuations reflect the gain and loss of simple sequence motifs by slippage-like mechanisms. We discuss the molecular coevolution of expansion segments, which takes place against a background of slippage-like and unequal crossing-over mechanisms of turnover that are responsible for the accumulation of interspecific differences in rDNA sequences.      

Cytogenetics of the South American Akodont rodents (Cricetidae) X. Akodon mollis: a species with XY females and B chromosomes

The morphology, G- and C-banding pattern of the Akodon mollis chromosome complement is analysed. Over a total of 14 males and 10 females studied, 8 males and 7 females had a modal chromosome number of 22, while 6 males and 3 females showed a modal number of 23 chromosomes. In the animals with 23 chromosomes the odd element was considered a B chromosome on the basis of: (a) its small size, (b) the lack of an homologous chromosome and the subsequent formation of univalents at diakinesis and metaphase I from testes, (c) the weak or null genetic action as evidenced by the lack of any obvious variation in the phenotype of carriers.Four females exhibited a sex-pair dimorphism indistinguishable from that observed in males. The G-banding analysis showed homology between the pattern found in the Y chromosome and that detected in the short arm of the X. The study of C-band distribution showed that several autosome pairs and the X chromosomes had small masses of centromeric heterochromatin. On the other hand, the Y and B chromosomes were C-band negative. The Y-like chromosome in females with dimorphism of the sex pair was also C-band negative. Accordingly these females were considered to be XY and not Xx (the x being an extensively deleted X chromosome).This work was supported by grants from UNESCO, OEA, CONICET and CIC. Requests for reprints should be addressed to N.O. Bianchi.