晚期肝癌和复发性肝癌治疗的研究进展

肝细胞癌(HCC)是我国最常见的恶性肿瘤之一,70%继发于肝炎、肝硬变。虽然诊断技术的提高,使肝癌的早期发现成为可能,然而由于肝癌早期症状隐匿,大多数肝癌确诊时已处于中晚期。肝切除术是治疗肝细胞癌最常用的手段。对于一些不可切除的晚期肝细胞癌,可采用动脉化疗栓塞以及系统化疗等手段使肿瘤降期,当转变成可切除肝癌后,再行补救性肝切除延长患者的生存期。此外,对于剩余肝体积不足而无法行一期肝切除的患者,可以采用PVE、ALPPS等方法,在剩余肝脏体积增大后再行二期肝切除术。肝内肿瘤复发率高也是导致肝细胞癌预后差的重要因素。在局部治疗后,建议在保留肝功能的前提下重复治疗。相比局部消融和动脉化疗栓塞治疗等多种手段,肝切除术有最好的远期疗效。联合和重复不同的治疗手段可达到很好的总生存期。对于患有晚期不可切除肿瘤或复发癌的患者,应积极的发挥肝切除的作用,并联合其他非手术治疗手段以取得较好的预后。     

When can we measure stress noninvasively? Postdeposition effects on a fecal stress metric confound a multiregional assessment

Measurement of stress hormone metabolites in fecal samples has become a common method to assess physiological stress in wildlife populations. Glucocorticoid metabolite (GCM) measurements can be collected noninvasively, and studies relating this stress metric to anthropogenic disturbance are increasing. However, environmental characteristics (e.g., temperature) can alter measured GCM concentration when fecal samples cannot be collected immediately after defecation. This effect can confound efforts to separate environmental factors causing predeposition physiological stress in an individual from those acting on a fecal sample postdeposition. We used fecal samples from American pikas (Ochotona princeps) to examine the influence of environmental conditions on GCM concentration by (1) comparing GCM concentration measured in freshly collected control samples to those placed in natural habitats for timed exposure, and (2) relating GCM concentration in samples collected noninvasively throughout the western United States to local environmental characteristics measured before and after deposition. Our timed‐exposure trials clarified the spatial scale at which exposure to environmental factors postdeposition influences GCM concentration in pika feces. Also, fecal samples collected from occupied pika habitats throughout the species' range revealed significant relationships between GCM and metrics of climate during the postdeposition period (maximum temperature, minimum temperature, and precipitation during the month of sample collection). Conversely, we found no such relationships between GCM and metrics of climate during the predeposition period (prior to the month of sample collection). Together, these results indicate that noninvasive measurement of physiological stress in pikas across the western US may be confounded by climatic conditions in the postdeposition environment when samples cannot be collected immediately after defecation. Our results reiterate the importance of considering postdeposition environmental influences on this stress metric, especially in multiregional comparisons. However, measurements of fecal GCM concentration should prove useful for population monitoring within an eco‐region or when postdeposition exposure can be minimized.     

Comparing two methods for estimating floral resource availability for insect pollinators in semi-natural habitats

Pollinator and flowering plant interactions play a critical role in maintaining most terrestrial ecosystems, including agroecosystems. Although estimates of floral resource availability are essential to understand plant–pollinator relationships, no generally accepted methodology exists to date. We compared two methods for sampling floral resources in a single meadow. About every three days, we recorded species lists of insect-pollinated plants with abundance categories assigned to each species (hereafter referred to as scanning) and we counted the flowering shoots in 36 2 × 2 m quadrats (hereafter quadrat sampling). These methods were compared with respect to (i) the number of species detected, (ii) estimated floral resource abundance, and (iii) temporal changes in flowering. With scanning, we found more potential nectar-plant species and species were found earlier than with quadrat sampling. With the latter, abundant species were found with higher probability than the scarce. Flower abundances were correlated between the two methods. We predicted that a cover of 6.3 ± 3.6% should be used for an appropriate estimate of flower abundance in our study site, although the optimal cover probably varies across different habitats. Furthermore, flower abundance changed 6% per day compared to the flowering peak. Overall, scanning seems to be more appropriate for detecting presence and the timing of species, while quadrats may provide higher resolution for abundance estimates. Increased sampling coverage and frequency may enhance research accuracy and using scanning and quadrat sampling simultaneously may help to optimize research effort. We encourage further development of sampling protocols.     

Temperature dependence on the pesticide sampling rate of polar organic chemical integrative samplers (POCIS)

Laboratory experiments were performed to determine the sampling rates of pesticides for the polar organic chemical integrative samplers (POCIS) used in Japan. The concentrations of pesticides in aquatic environments were estimated from the accumulated amounts of pesticide on POCIS, and the effect of water temperature on the pesticide sampling rates was evaluated. The sampling rates of 48 pesticides at 18, 24, and 30 °C were obtained, and this study confirmed that increasing trend of sampling rates was resulted with increasing water temperature for many pesticides.     

Severe extinction and rapid recovery of mammals across the Cretaceous–Palaeogene boundary,and the effects of rarity on patterns of extinction and recovery

The end‐Cretaceous mass extinction ranks among the most severe extinctions of all time; however, patterns of extinction and recovery remain incompletely understood. In particular, it is unclear how severe the extinction was, how rapid the recovery was and how sampling biases might affect our understanding of these processes. To better understand terrestrial extinction and recovery and how sampling influences these patterns, we collected data on the occurrence and abundance of fossil mammals to examine mammalian diversity across the K‐Pg boundary in North America. Our data show that the extinction was more severe and the recovery more rapid than previously thought. Extinction rates are markedly higher than previously estimated: of 59 species, four survived (93% species extinction, 86% of genera). Survival is correlated with geographic range size and abundance, with widespread, common species tending to survive. This creates a sampling artefact in which rare species are both more vulnerable to extinction and less likely to be recovered, such that the fossil record is inherently biased towards the survivors. The recovery was remarkably rapid. Within 300 000 years, local diversity recovered and regional diversity rose to twice Cretaceous levels, driven by increased endemicity; morphological disparity increased above levels observed in the Cretaceous. The speed of the recovery tends to be obscured by sampling effects; faunas show increased endemicity, such that a rapid, regional increase in diversity and disparity is not seen in geographically restricted studies. Sampling biases that operate against rare taxa appear to obscure the severity of extinction and the pace of recovery across the K‐Pg boundary, and similar biases may operate during other extinction events.     

Mate choice and the operational sex ratio: an experimental test with robotic crabs

The operational sex ratio (OSR: sexually active males: receptive females) predicts the intensity of competition for mates. It is less clear, however, under what circumstances, the OSR predicts the strength of sexual selection – that is, the extent to which variation in mating success is attributable to traits that increase the bearer's attractiveness and/or fighting ability. To establish causality, experiments that manipulate the OSR are required. Furthermore, if it is possible to control for any OSR‐dependent changes in the chosen sex (e.g. changes in male courtship), we can directly test whether the OSR affects the behaviour of the choosing sex (e.g. female choice decisions). We conducted female mate choice experiments in the field using robotic models of male fiddler crabs (Uca mjoebergi). We used a novel design with two females tested sequentially per trial. As in nature, the choice of the first female to mate therefore affected the mates available to the next female. In general, we detected significant sexual selection due to female choice for ‘males’ with larger claws. Importantly, the strength of sexual selection did not vary across five different OSR/density treatments. However, as the OSR decreased (hence the number of available males declined), females chose the ‘males’ with the largest claws available significantly more often than expected by chance. Possible reasons for this mismatch between the expected and observed effects of the OSR on the strength of sexual selection are discussed.     

植菌昆虫与其共生真菌协同进化分子机制

昆虫菌业（fungiculture）是一种类似于人类种植业的昆虫种植体系,包括种植、耕作、收获和营养依赖4个过程,可分为高级的社会性昆虫如切叶蚂蚁、白蚁等和低级的非社会性昆虫如食菌小蠹虫、卷叶象甲、蜥蜴甲虫、树蜂等,它们均能种植并取食真菌。近年来随着组学及微生物组技术的发展,植菌昆虫与其共生真菌协同进化的分子机制研究方面取得了重要进展。系统发育分析阐明了植菌昆虫的起源与进化历程,并显示出与共生真菌系统发育的一致性;共生真菌细胞核数量也从双核增加到最多17个核,而染色体倍型也从单倍体增加为二倍体甚至多倍体;组学分析则揭示了植菌昆虫与其共生真菌在精氨酸、碳水化合物、木质素及几丁质合成或降解等方面显示出了高度的协同进化。本文系统综述了植菌昆虫及其共生真菌的系统进化、核进化及基因组进化进展,并探讨这种协同进化机制的生物学意义。