可切除的食管胃结合部腺癌的联合治疗

近年来胃癌的发病率有所下降,相比之下胃食管结合部腺癌的发病率却快速增长。手术治疗仍然是早期食管胃结合部腺癌的标准治疗方法,同时手术联合化疗、放化疗治疗食管胃结合部腺癌也逐渐得到国际认可。尽管在手术治疗、放疗和化疗治疗技术得到完善和改进,但食管癌和食管胃结合部腺癌的预后仍然较差。目前有数个大型临床随机对照试验数据支持对食管下端和食管胃交界部腺癌使用术前联合化疗,但辅助治疗的贡献仍不能确定。最近有meta分析表明手术联合化疗、放化疗可以提高胃食管结合部腺癌患者术后存活率,但也有一些临床随机试验的数据表明手术联合化疗、放化疗并无明显好处。本文通过总结最新的临床试验及meta分析结果,阐述不同的可切除的胃食管结合部腺癌的联合治疗方法。     

黑龙江和图们江流域菱属(Trapa L.)植物分布格局及形态多样性

菱属(Trapa L.)的系统分类一直存在较大分歧,至今还没有一个比较公认的分类系统。黑龙江和图们江流域是菱属物种多样性的重要分布区之一,为了揭示该流域菱属植物的地理分布格局和形态多样性,我们进行了大量实地调查和研究。结果显示,从该地区28个湖中共采集到菱属11个种及8个种内变异类型,表明它们具有丰富的形态多样性;结合查阅菱属354份标本资料,共获得92个分布地点数据;采集到的11个物种的地理分布格局呈不均衡性,其中细果野菱(Trapa maximowiczii Korsch.)分布最广,野菱(Trapa incisa Siebold et Zucc.)、兴凯菱(Trapa khankensis Pshennikova)和科热夫尼科夫菱(Trapa kozhevnikovirum Pshennikova)为狭域分布种;东部乌苏里江和图们江流域是菱属物种多样性的分布中心,可能是第四纪冰期避难所;菱属植物多数种间形态特性相对稳定,东北菱(Trapa manshurica Fler.)、耳菱(Trapa potaninii V.Vassil)、丘角菱(Trapa japonica Fler.)、西伯利亚菱(Trapa sibirica Fler.)和细果野菱共有8个种内形态变异类型;种群内多数分类性状稳定,种群间形态变异较明显;菱属植物分布格局不均衡和种内形态变异的形成可能与基因流的扩散限制有关。本研究结果为进一步澄清菱属分类混乱问题奠定了基础,进一步结合分子标记技术研究系统演化关系将对揭示菱属的进化历史具有重要意义。     

Comparison of dot chromosome sequences from D. melanogaster and D. virilis reveals an enrichment of DNA transposon sequences in heterochromatic domains

Background

Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago.

Results

Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %).

Conclusion

Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging.     

Biologically relevant effects of mRNA amplification on gene expression profiles

Background  

Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results.     

Paradoxical (REM) sleep genesis: The switch from an aminergic–cholinergic to a GABAergic–glutamatergic hypothesis

In the middle of the last century, Michel Jouvet discovered paradoxical sleep (PS), a sleep phase paradoxically characterized by cortical activation and rapid eye movements and a muscle atonia. Soon after, he showed that it was still present in “pontine cats” in which all structures rostral to the brainstem have been removed. Later on, it was demonstrated that the pontine peri-locus coeruleus α (peri-LCα in cats, corresponding to the sublaterodorsal nucleus, SLD, in rats) is responsible for PS onset. It was then proposed that the onset and maintenance of PS is due to a reciprocal inhibitory interaction between neurons presumably cholinergic specifically active during PS localized in this region and monoaminergic neurons. In the last decade, we have tested this hypothesis with our model of head-restrained rats and functional neuroanatomical studies. Our results confirmed that the SLD in rats contains the neurons responsible for the onset and maintenance of PS. They further indicate that (1) these neurons are non-cholinergic possibly glutamatergic neurons, (2) they directly project to the glycinergic premotoneurons localized in the medullary ventral gigantocellular reticular nucleus (GiV), (3) the main neurotransmitter responsible for their inhibition during waking (W) and slow wave sleep (SWS) is GABA rather than monoamines, (4) they are constantly and tonically excited by glutamate and (5) the GABAergic neurons responsible for their tonic inhibition during W and SWS are localized in the deep mesencephalic reticular nucleus (DPMe). We also showed that the tonic inhibition of locus coeruleus (LC) noradrenergic and dorsal raphe (DRN) serotonergic neurons during sleep is due to a tonic GABAergic inhibition by neurons localized in the dorsal paragigantocellular reticular nucleus (DPGi) and the ventrolateral periaqueductal gray (vlPAG). We propose that these GABAergic neurons also inhibit the GABAergic neurons of the DPMe at the onset and during PS and are therefore responsible for the onset and maintenance of PS.     

Paradoxical (REM) sleep genesis: the switch from an aminergic-cholinergic to a GABAergic-glutamatergic hypothesis.

In the middle of the last century, Michel Jouvet discovered paradoxical sleep (PS), a sleep phase paradoxically characterized by cortical activation and rapid eye movements and a muscle atonia. Soon after, he showed that it was still present in "pontine cats" in which all structures rostral to the brainstem have been removed. Later on, it was demonstrated that the pontine peri-locus coeruleus alpha (peri-LCalpha in cats, corresponding to the sublaterodorsal nucleus, SLD, in rats) is responsible for PS onset. It was then proposed that the onset and maintenance of PS is due to a reciprocal inhibitory interaction between neurons presumably cholinergic specifically active during PS localized in this region and monoaminergic neurons. In the last decade, we have tested this hypothesis with our model of head-restrained rats and functional neuroanatomical studies. Our results confirmed that the SLD in rats contains the neurons responsible for the onset and maintenance of PS. They further indicate that (1) these neurons are non-cholinergic possibly glutamatergic neurons, (2) they directly project to the glycinergic premotoneurons localized in the medullary ventral gigantocellular reticular nucleus (GiV), (3) the main neurotransmitter responsible for their inhibition during waking (W) and slow wave sleep (SWS) is GABA rather than monoamines, (4) they are constantly and tonically excited by glutamate and (5) the GABAergic neurons responsible for their tonic inhibition during W and SWS are localized in the deep mesencephalic reticular nucleus (DPMe). We also showed that the tonic inhibition of locus coeruleus (LC) noradrenergic and dorsal raphe (DRN) serotonergic neurons during sleep is due to a tonic GABAergic inhibition by neurons localized in the dorsal paragigantocellular reticular nucleus (DPGi) and the ventrolateral periaqueductal gray (vlPAG). We propose that these GABAergic neurons also inhibit the GABAergic neurons of the DPMe at the onset and during PS and are therefore responsible for the onset and maintenance of PS.     

不同放牧强度下短花针茅荒漠草原植被的空间异质性

分析不同放牧强度下植物群落中物种的空间分布特征, 有助于阐明群落在放牧胁迫下的演替规律。该研究基于幂函数法则, 探讨了不同放牧强度下短花针茅(Stipa breviflora)荒漠草原群落植物的频率和空间异质性。结果表明: 不同放牧强度下物种空间分布与幂函数法则能很好地吻合; 不同物种空间异质性具有特异性, 随着放牧强度的增加, 提高群落空间异质性的物种分别由无芒隐子草(Cleistogenes songorica)、冷蒿(Artemisia frigida)、短花针茅、银灰旋花(Convolvulus ammannii)等多个物种逐渐转变为以无芒隐子草、短花针茅为主的少数物种, 同时, 物种空间异质性大于群落空间异质性的物种数逐渐减少。     

Amblyomma sculptum: genetic diversity and rickettsias in the Brazilian Cerrado biome

Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888 is the most important tick vector in Brazil, transmitting the bioagent of the most severe form of spotted fever (SF) in part of the Cerrado (in the states of Minas Gerais and São Paulo). In another part of the Cerrado (Central‐West region of Brazil), a milder form of SF has been recorded. However, neither the rickettsia nor the vector involved have been characterized. The aim of the current study was to analyse genetic variation and the presence of rickettsia in A. sculptum in Cerrado, from silent areas and with the milder form of SF. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D‐loop mitochondrial genes (for tick population analyses), and gltA, htrA, ompA and gene D (sca4) genes for rickettsia researches. Exclusive haplotypes with low frequencies, high haplotype diversity and low nucleotide diversity, star‐shaped networks and significant results in neutrality tests indicate A. sculptum population expansions in some areas. Rickettsia amblyommatis, Candidatus Rickettsia andeanae and Rickettsia felis were detected. The A. sculptum diversity is not geographically, or biome delimited, pointing to a different potential in vector capacity, possibly associated with differing tick genetic profiles.     

Effects of reduced salinities on development and bioenergetics of early larval shore crab, Carcinus maenas

The shore crab, Carcinus maenas L. (Portunidae), is a coastal and estuarine species, which can live and reproduce under brackish water conditions; freshly hatched larvae have been observed in the field at salinities below 15‰. In the present laboratory study, the tolerance of hypo-osmotic stress was experimentally investigated in early larvae of a marine (North Sea) population of C. maenas reared at four different salinities (15, 20, 25, 32‰). Two and 4 days after hatching, the Zoea I larvae were moult-staged microscopically, and their rates of respiration and growth (changes in dry weight, W, carbon, C, nitrogen, N, and hydrogen, H) were measured. Survival and development were monitored until the megalopa was reached: 15‰ did not allow for development beyond the first zoeal stage, while metamorphosis to the megalopa was reached at salinities ≥20‰. At 20‰, development was significantly delayed and mortality enhanced as compared with 25 and 32‰. Rates of growth and respiration decreased during exposure to reduced salinities ≤25‰. Hence, the suppression of growth could not be explained as a consequence of enhanced metabolic losses per larva. Instead, a partial C budget indicates that the Zoea I larvae suffered from decreased capabilities of assimilating ingested and subsequently converting assimilated matter to tissue growth. Net growth efficiency (K₂, C-based) was at 25 and 32‰ initially high (>60% during the postmoult and intermoult stages of the Zoea I moult cycle), but decreased during the later stages (down to ≤30% in premoult). An inverse pattern of C partitioning was observed at ≤20‰, with initially low K₂ values (≤21% during the first 2 days of the moult cycle), and a later increase (up to ≥46% in premoult). Thus, larval growth was initially suppressed under conditions of reduced salinity, but this was later (during premoult) partially compensated for by an increase in C assimilation and K₂. Our observations indicate that Zoea I shore crab larvae react during the late stages of their moulting cycle less sensitively against reduced salinities than during postmoult and intermoult. This suggests that the transition between moult cycle stages C and D₀ may be a critical point for effects of hypo-osmotic stress, similarly as already known in relation to effects of nutritional stress. Negative effects were found also when freshly hatched Zoea I shore crab larvae were exposed only transitorily (for 24–72 h) to 20‰, with significantly lower rates of survival, development, growth, respiration, and K₂. These effects increased with increasing duration of initial exposure to reduced salinity.     

The ontogeny of the female reproductive system in the parasitic castrator pea crab Calyptraeotheres garthi: Implications for its mating system

The knowledge of the mating system of pea crabs is still fragmentary as it remains dubious whether females copulate in the juvenile and free‐living ‘hard’ or in the obligatory symbiotic stages (adult stage ‘V’ or intermediate stages II to IV). To discriminate between these two possibilities, we analysed the female seminal receptacles, vagina and opercula, and the sperm content in different stages of the pea crab Calyptraeotheres garthi. Our histology and scanning electron microscopy results revealed that in the hard stage the seminal receptacle is simple without secretory epithelia, and vagina and opercula are not controlled by musculature. In stages II to IV, the seminal receptacles, vagina, and opercula are under development and these structures reach maturity in stage V. These results suggest that females become receptive in stage V and not during predating stages. We found no spermatozoa in SR of ‘hard’ and stage II to IV females while these structures were loaded of sperm in most stage V, indicating that females start to mate in stage V. Our results support the notion that males of C. garthi roam among hosts in search for sedentary stage V females, as predicted by Baeza and Thiel's ( 2007 ) model of mating systems for symbiotic crustaceans. Nevertheless, we failed to reveal whether females mate repeatedly: the accumulation of sperm in larger females might indicate occurrence of multiple copula or a high variability in male sperm transfer.