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研究生教育

最新医学科研信息(第59期)

  • 2014/06/06

最新医学科研信息
(2014年6月6日)
目 录
1、A brief history of altmetrics
2、乳腺癌相关基因变异增肺癌风险
3、抗肺癌新药CM118将进入临床
4、我国新增肺癌全球居首 吸烟喝酒成致癌主因
5、早产或与胎盘中微生物有关
6、从动物粪便中萃取牲畜饮用水
7、粪便移植逐渐为主流医学界接受
8、肠促胰岛素类药物不增加急性胰腺炎风险
1、A brief history of altmetrics
“No one can read everything. We rely on filters to make sense of the scholarly literature, but the narrow, traditional filters are being swamped. However, the growth of new, online scholarly tools allows us to make new filters; these altmetrics reflect the broad, rapid impact of scholarship in this burgeoning ecosystem. We call for more tools and research based on altmetrics. (1)”
The above manifesto signaled the birth of altmetrics. It grew from the recognition that the social web provided opportunities to create new metrics for the impact or use of scholarly publications. These metrics could help scholars find important articles and perhaps also evaluate the impact of their articles. At the time there was already a field with similar goals, webometrics, which had created a number of indicators from the web for scholars (e.g., 2) and scholarly publications (e.g., 3), including genre-specific indicators, such as syllabus mentions (4). Moreover, article download indicators (e.g., 5) had also been previously investigated. Nevertheless, altmetrics have been radically more successful because of the wide range of social web services that could be harnessed, from Twitter to Mendeley, and because of the ease with which large scale data could be automatically harnessed from the social web through Applications Programming Interfaces (APIs). Academic research with multiple different approaches is needed to evaluate their value, however (6).
1 Scholarly use of the social web
Some research has investigated how scholars use social web services, giving insights into the kinds of activities that altmetrics might reflect. In some cases the answers seem straightforward; for example Mendeley is presumably used to store the academic references that users are interested in – perhaps articles that they have previously read or articles that they plan to read. Counts of article “Readers” in Mendeley might therefore be similar to citation counts in the sense that they could reflect the impact of an article. Mendeley has the advantage that its metrics could be available sooner than traditional citations, since there is no publication delay, and its user base is presumably wider than just publishing scientists. Nevertheless, there are biases, such as towards more junior researchers (7).
In comparison to Mendeley, Twitter has a wider user base and a wider range of potential uses. Nevertheless, it seems that only a minority of articles get tweeted – for example, perhaps as few as 10% of PubMed articles in the Web of Science 2010-2012 have been tweeted (8). Scholars seem to use Twitter to cite articles, but sometimes indirectly (9), which may cause problems for automatically harvesting these citations. Moreover, most tweet (link) citations seem to be relatively trivial in the sense of echoing an article title or a brief summary rather than critically engaging with it (10). There are also disciplinary differences in the extent to which Twitter is used and what it is used for (11) and so, as with citations, Twitter altmetrics should not be used to compare between fields. Another problem is that users may also indicate awareness of others’ work by tweeting to them or tweeting about their ideas without citing specific publications (12).
2 Evidence for the value of altmetrics
If article level altmetrics are to be useful to help direct potential readers to the more important articles in their field then evidence would be needed to show that articles with higher altmetric scores tended to be, in general, more useful to read. It would be difficult to get direct empirical verification, however, since data from readers about many articles would be needed to cross-reference with altmetric scores. Perhaps the most practical way to demonstrate the value of an altmetric is to show that it can be used to predict the number of future citations to articles, however, since citations are an established indicator of article impact, at least at the statistical level (more cited articles within a field tend to be more highly regarded by scholars, e.g., 13), even though there are many individual examples of articles for which citations are not a good guide to their value. This has been done for tweets to one online medical journal (14) and for citations in research blogs (15). This approach has double value because it shows that altmetric scores are not random but associate with an established (albeit controversial) impact measure and also shows that altmetrics can give earlier evidence of impact than can citation counts.
A second way of getting evidence of the value of altmetrics is to show that their values correlate with citation counts, without demonstrating that the former preceded the latter (of course, correlation does not imply causation and a lack of correlation does not imply worthlessness, but a correlation does imply a relationship with citation impact or at least some of the factors that cause citation impact). This gives some evidence of the validity of altmetrics as an impact indicator but not of their value as an early impact indicator. For example, a study showed that the number of Mendeley readers of articles in the Science and Nature magazines correlated with their citations, but did not prove that Mendeley reader data was available before citation counts (16).
Although the above studies provide good evidence that some altmetrics could have value as impact indicators for a small number of journals, larger scale studies are needed to check additional indicators and a wider range of journals in order to get more general evidence. In response, a large-scale study investigated 11 different altmetrics and up to 208,739 PubMed articles for evidence of a relationship between citations and altmetric scores gathered for 18 months from July 2011. The study found most altmetrics to have a statistically significant positive (Spearman) correlation with citations but one that was too small to be of practical significance (below 0.1). The exceptions were blogs (0.201), research highlights (0.373) and Twitter (-0.190). The reason for the negative correlation for Twitter, and perhaps also for the low correlations in many other cases, could be the rapid increase in citing academic articles in social media, leading to more recent articles being more mentioned even though they were less cited. This suggests that, in most cases, altmetrics have little value for comparing articles published at different points in time, even within the same year. To assess the ability of altmetrics to differentiate between articles published at the same time and in the same journal, the study ran a probabilistic test for up to 1,891 journals per metric to see whether more cited articles tended to have higher altmetric scores, benchmarking against approximately contemporary articles from the same journal. The results gave statistical evidence of an association between higher altmetric scores and citations for most of them for which sufficient data was available (Twitter, Facebook, research highlights, blogs, mainstream media, forums) (17). In summary, it seems that although many altmetrics may have value as indicators of impact, differences over time are critical and so altmetrics need to be normalized in some way in order to allow valid comparisons over time, or they should only be used to compare articles published at the same time (exception: blogs and research highlights).
3 Other uses for altmetrics
Altmetrics also have the potential to be used for impact indicators for individual researchers based upon their web presences, although this information should not be used as a primary source of impact information since the extent to which academics possess or exploit social web profiles is variable (e.g., 18; 19; 20). More widely, however, altmetrics should not be used to help evaluate academics for anything important, unless perhaps as complementary measures, because of the ease with which they can be manipulated. In particular, since social websites tend to have no quality control and no formal process to link users to offline identities it would be easy to systematically generate high altmetric scores for any given researcher or set of articles.
A promising future direction for research is to harness altmetrics in new ways in order to gain insights into aspects of research that were previously difficult to get data about, such as the extent to which articles from a field attract readerships from other fields (21) or the value of social media publicity for articles (22). Future research also needs to investigate disciplinary differences in the validity and value of different types of altmetrics. Currently it seems that most articles don’t get mentioned in the social web in a way that can be easily identified for use in altmetrics (e.g., 23), but this may change in the future.
4 References
(1) Priem, J., Taraborelli, D., Groth, P. & Neylon, C. (2010) “Altmetrics: A manifesto”, http://altmetrics.org/manifesto/
(2) Cronin, B., Snyder, H.W., Rosenbaum, H., Martinson, A. & Callahan, E. (1998) “Invoked on the Web”, Journal of the American Society for Information Science, Vol. 49, No. 14, pp. 1319-1328.
(3) Vaughan, L. & Shaw, D. (2003) “Bibliographic and web citations: what is the difference?”, Journal of the American Society for Information Science and Technology, Vol.54, No. 14, pp. 1313-1322.
(4) Kousha, K. & Thelwall, M. (2008) “Assessing the impact of disciplinary research on teaching: An automatic analysis of online syllabuses”, Journal of the American Society for Information Science and Technology, Vol. 59, No. 13, pp. 2060-2069.
(5) Shuai, X., Pepe, A., & Bollen, J. (2012) “How the scientific community reacts to newly submitted preprints: Article downloads, Twitter mentions, and citations”, PLOS ONE, Vol. 7 No. 11, e47523.
(6) Sud, P. & Thelwall, M. (2014) “Evaluating altmetrics”, Scientometrics, Vol. 98, No. 2, pp. 1131-1143.
(7) Mohammadi, E., Thelwall, M., Haustein, S. & Larivière, V. (in press) “Who reads research articles? An altmetrics analysis of Mendeley user categories”, Journal of the Association for Information Science and Technology.
(8) Haustein, S., Peters, I., Sugimoto, C.R., Thelwall, M. & Larivière, V. (in press) “Tweeting biomedicine: An analysis of tweets and citations in the biomedical literature”, Journal of the Association for Information Science and Technology.
(9) Priem, J., & Costello, K.L. (2010) “How and why scholars cite on Twitter”, Proceedings of the American Society for Information Science and Technology, Vol. 47, pp. 1-4.
(10) Thelwall, M., Tsou, A., Weingart, S., Holmberg, K. & Haustein, S. (2013) “Tweeting links to academic articles”, Cybermetrics: International Journal of Scientometrics, Informetrics and Bibliometrics, Vol. 17, No. 1, paper 1.
(11) Holmberg, K. & Thelwall, M. (in press) “Disciplinary differences in Twitter scholarly communication”, Scientometrics.
(12) Weller, K., Dröge, E. & Puschmann, C. (2011) “Citation analysis in Twitter: Approaches for defining and measuring information flows within tweets during scientific conferences”, In Proceedings of Making Sense of Microposts Workshop (# MSM2011).
(13) Franceschet, M. & Costantini, A. (2011) “The first Italian research assessment exercise: A bibliometric perspective”, Journal of Informetrics, Vol. 5, No. 2, pp. 275-291.
(14) Eysenbach, G. (2011) “Can tweets predict citations? Metrics of social impact based on Twitter and correlation with traditional metrics of scientific impact”, Journal of Medical Internet Research, Vol.13, No. 4, e123.
(15) Shema, H., Bar-Ilan, J. & Thelwall, M. (2014) “Do blog citations correlate with a higher number of future citations? Research blogs as a potential source for alternative metrics”, Journal of the Association for Information Science and Technology, Vol. 65, No. 5, pp. 1018–1027.
(16) Li, X., Thelwall, M. & Giustini, D. (2012) “Validating online reference managers for scholarly impact measurement”, Scientometrics, Vol. 91, No. 2, pp. 461-471.
(17) Thelwall, M., Haustein, S., Larivière, V. & Sugimoto, C. (2013) “Do altmetrics work? Twitter and ten other candidates”, PLOS ONE, Vol. 8, No. 5, e64841. doi:10.1371/journal.pone.0064841
(18) Bar-Ilan, J., Haustein, S., Peters, I., Priem, J., Shema, H. & Terliesner, J. (2012) “Beyond citations: Scholars' visibility on the social Web”, Proceedings of 17th International Conference on Science and Technology Indicators (pp. 98-109), Montréal: Science-Metrix and OST.
(19) Haustein, S., Peters, I., Bar-Ilan, J., Priem, J., Shema, H. & Terliesner, J. (in press) “Coverage and adoption of altmetrics sources in the bibliometric community”, Scientometrics.
(20) Mas Bleda, A., Thelwall, M., Kousha, K. & Aguillo, I. (2013) “European highly cited scientists’ presence in the social web”, In 14th International Society of Scientometrics and Informetrics Conference (ISSI 2013) (pp. 98-109).
(21) Mohammadi, E. & Thelwall, M. (in press) “Mendeley readership altmetrics for the social sciences and humanities: Research evaluation and knowledge flows”, Journal of the Association for Information Science and Technology.
(22) Allen, H.G., Stanton, T.R., Di Pietro, F. & Moseley, G.L. (2013) “Social media release increases dissemination of original articles in the clinical pain sciences”, PloS ONE, Vol. 8, No. 7, e68914.
(23) Zahedi, Z., Costas, R. & Wouters, P. (in press) “How well developed are Altmetrics? Cross-disciplinary analysis of the presence of “alternative metrics” in scientific publications”, Scientometrics.
2、乳腺癌相关基因变异增肺癌风险
一项大规模国际研究发现,一种与乳腺癌有关的基因变异会显著增加肺癌风险,尤其是吸烟者如果出现这一基因变异,其患肺癌的风险要比不吸烟者高出近80倍。
研究小组在新一期英国《自然—遗传学》杂志上介绍说,他们对约1.1万名患有肺癌的欧洲人与约1.5万名未患肺癌的人进行了基因状况对比。结果发现,一种名为“BRCA-2”的基因变异与肺癌患病风险明显相关。而且医学界早就发现,“BRCA-2”与“BRCA-1”这两种基因变异与乳腺癌、卵巢癌发病有关。研究人员据此认为目前针对乳腺癌的疗法或许可改善肺癌治疗。
“BRCA-2”基因的变异尤其应该引起吸烟者高度警惕。此次研究发现,“BRCA-2”基因变异的吸烟者中,约四分之一的人会患肺癌,而不携带此基因变异的吸烟者患肺癌的风险约为15%。
参与研究的英国癌症研究所专家说,与不吸烟者相比,吸烟者患肺癌的风险要高出40倍。而新研究发现,出现“BRCA-2”基因变异的吸烟者患肺癌的风险高出近80倍,因此这一人群需要高度警惕这种风险,对他们来说最重要的是早日戒烟。
3、抗肺癌新药CM118将进入临床
日前,上海再新医药科技有限公司宣布,公司的抗肺癌新药CM118项目已经完成临床前研究,并向上海市食品药品监督管理局提交临床申请。
CM118是一种选择性MET激酶和ALK激酶抑制剂,它是直接针对美国辉瑞公司已上市的新型ALK激酶抑制剂抗肺癌新药克唑替尼而设计,在保留其优点的基础上,进一步克服克唑替尼的药物相互作用的缺点,扩展这一类新型抗癌药与其他抗癌药联合应用的可能性,大幅度提高治疗效果。
临床前试验结果显示,CM118很可能达到了预期的设计目标。同时,MET激酶与肿瘤生长、转移扩散直接有关,它也是目前临床常用的高端一类抗癌药如厄洛替尼、吉非替尼、阿瓦斯汀等的重要耐药性机制。MET激酶抑制剂的临床试验证明其对非小细胞肺癌等有很好的效果。
4、我国新增肺癌全球居首 吸烟喝酒成致癌主因
据世界卫生组织下属的国际癌症研究机构发表的《2014年世界癌症报告》指出,全球癌症患者数量正以惊人的速度增加,其中中国新增肺癌全球居首,这也引发网友对于雾霾与肺癌的关系、戒烟是否真的能控制肺癌等的热议。

吸烟喝酒成都市人致癌主因

据世界卫生组织下属的国际癌症研究机构发表的《2014年世界癌症报告》指出,2012年导致死亡最多的前三类癌症依次是肺癌、肝癌和胃癌,它们都与生活方式密切相关。北京大学肿瘤医院党委副书记杨跃在接受中新网健康频道专访时表示,吸烟已成为肺癌发病的首因,根据统计,得肺癌的病人有87%跟吸烟相关,21%的冠心病人曾吸烟,全身的各个器官的肿瘤有31%跟吸烟相关,而我们肺部的慢性疾病加重更是有82%和跟吸烟相关。

“如果说雾霾是个大环境、外环境,对于肺癌而言还有一个净环境,吸二手烟,生活场所,咱们生活的居室,这种小环境,也是非常重要,呼吸道直接诱导呼吸道得病的因素叫内环境,男性吸烟导致的二手烟对家族里的女性,如母亲、姐姐等最有影响。”杨跃说道。

他表示,目前国际上现在又新的一个理念“三手烟”,也值得警惕和预防。所谓的三手烟,是男性没有在家抽烟,他们在外头应酬抽完烟以后,回家后没有在屋里头抽烟,也没有给太太儿子带来二手烟的机会,但是他们脱掉的衣服放在洗衣机旁边,“太太要洗衣服,孩子们会看看兜里面有什么东西,这个抖的过程当中吸的是三手烟,已经越来越多的被医学家们关注了。”

除了吸烟以外,喝白酒、生活不规律、精神紧张是都市白领和民众致癌的原因。杨跃透露,自身免疫力在老百姓来说是些很简单的道理,比如这一宿值夜班了,过年人好不容易回来了,大家打个牌,看个春晚聊聊天,喝点小酒,吃个饺子,大半宿过去入睡已经三四点钟了,大家想想,这样接连几天下来,是不是突然发现体制明显下降,感冒了,这些都说明生活不规律。

“一个突发的不规律的生活势必要得病,得小病能过去,得大病就等于把定时炸弹潜伏在身体里了。人的作息时间就像一个生物钟,生物钟有一个波动,所以不管男性还是女性都一样,该休息的时候休息,学会养精蓄锐。”杨跃建议道。

欧美国家推强行戒烟 中国主要靠媒体宣传

随着癌症发病率的居高不下,近20年时间里,英法德美等国强行在国内实行戒烟,新加坡推行更强行的戒烟。不过我国在戒烟方面的教育主要是通过媒体进行宣传。

杨跃在接受中新网健康频道采访时表示,近20年时间里,英法德等国强行在国内实行戒烟,尽量减少香烟。他们做的国民流行病肺癌调查发现,吸烟者少了,肺癌发病率下降了。美国人也发现这个事实了,他们也重视这个,新加坡更加强行的戒烟。美国人也发现,吸烟人数下降,肺癌发病率也下降了,美国人把一些高危吸烟人群强行送去体检,做一个很简单的胸部的CT。早诊的人多了,他们发现治愈率也提高了。

“我国的报纸,网络,电视,广播都在宣传吸烟有害,但这样潜移默化的宣传需要无时无刻去做。他说,国外戒烟分几部曲,一是医务人员、心理医生的宣教,跟戒烟者接触、交谈,进一步到规劝:怎么从生活上注意,在哪些环节让吸烟的想法淡化。国外有各种各样的戒烟措施甚至药品,医院工作者会提供给抽烟人,甚至给他安排戒烟的时间段计划表。”杨跃说,国外已经把吸烟作为一种危险的生活习惯看待,必须戒掉。

同时杨跃还表示,目前我国戒烟多靠媒体和医院宣传健康知识,力度远远不够,还需要建立分步骤的实际操作方法,从操作技术上多一些改变。“外部在监督力度上还是应该加大,监督方式上需要改变,多一些技巧。尽管国内现在到处都有禁止吸烟的标识场所,但再怎么标识,如医院里也标识了整个外科大楼、门诊大楼不许抽烟,但还是有些家属就在这些大楼楼道里抽烟,“我们楼道是给病人去做锻炼,走路,锻炼,练习肺活量的地方,我们现在跟病人说不许到那儿去了,到那儿烟味太大了。”但在新加坡,将供吸烟使用的垃圾筒放在离住院大楼5米以外,有的人嫌远就不抽了。

杨跃接着表示,光靠医生和媒体工作者去宣传吸烟有害成效不大,重点是让吸烟的人去实施戒烟的过程。国外有借鉴的做法。国外戒烟是分几部曲,有步骤、分阶段进行。国外先是由戒烟或者医务人员、心理医生进行宣教,然后会跟吸烟者接触、逐渐的交谈、进一步规劝,让吸烟者从生活上注意哪些环节去淡化吸烟的欲望,“乃至到在国外也有一些戒烟的措施甚至药品,医院会给吸烟者安排戒烟的时间段、计划表,我国光靠媒体和医生宣传的作用还是不大。”

让“小皇帝”规劝监督家人戒烟是好方式

戒烟,对于每一个拥有长烟龄的人来说,都是一件痛苦的事,杨跃在接受中新网健康频道采访时表示,在戒烟的环节上,首先要给儿童或者青少年传授健康知识,现在的家庭大多是独生子女,父辈会比较重视孩子们的反应。“将吸烟有害的知识传授给孩子,他第一时间的脑子里接触了这个知识,他知道这个太可怕了,会介绍给爸爸妈妈”。

他认为,不仅是传授知识,并且可以让孩子去监督父辈们戒烟,这是一种比较有效的劝诫方式。“其实通过我们的媒体、这些老师们的宣传,监督的力度还是不够。但他们回到家里有一个小皇上式的孩子们去限制他们,效果可能好很多了。”
5、早产或与胎盘中微生物有关
美国一个研究小组说,孕妇胎盘并不像人们此前认为的那样是一个无菌环境,而是生存着一个小型但多元的微生物群落。这些微生物直接影响胎儿的健康,甚至可能与胎儿是否早产有关。
微生物群落是细菌、病毒与真菌等的总称。休斯敦贝勒医学院副教授谢斯蒂•奥高及同事报告说,新研究表明,孕妇胎盘中的微生物可能来自口腔,说明孕妇口腔健康对胎儿健康至关重要。此外,早产胎儿与足月产胎儿的胎盘微生物群落组成存在明显不同,说明胎盘微生物群落与早产之间可能存在关联。
长期以来,医学界认为胎盘是一个无菌的环境。而奥高等人此前发现,婴儿出生时肠道内就有微生物群落存在,但与孕妇阴道中的微生物群落并不匹配,因此猜测新生儿肠道内的微生物群落存在其他来源,最有可能就是胎盘。
在新研究中,奥高等人利用宏基因组鸟枪测序法,分析320个来自捐赠的胎盘的微生物组成,发现胎盘中有大约300种微生物存在,不过水平较低,其中大多数微生物都发挥着重要作用,比如为发育中的胎儿代谢维生素。
宏基因组又称元基因组或生态基因组,是指与人类共生的全部微生物的基因总和。鸟枪测序首先将整个基因组打乱,切成随机片段,然后测定每个小片段的序列,最终利用计算机对这些切片进行排序和组装,并确定它们在基因组中的正确位置。
研究还表明,胎盘中数量最多的是肠道中常见的、不致病的大肠杆菌,两种口腔菌坦纳氏普雷沃氏菌与奈瑟菌数量也相对较多。总体而言,胎盘的微生物群落组成与在口腔中发现的微生物群落最为相似。
奥高猜测,口腔微生物可能首先“溜”入孕妇血液之中,然后迁徙到胎盘“定居”。她说,这说明女性怀孕期间保持口腔健康的重要性,“强化了一个长期以来的观点——牙周疾病与早产风险存在关系”。
研究人员还发现,早产孕妇胎盘的微生物群落组成不同于足月产孕妇的胎盘。但奥高表示,目前还不清楚是否是这种差异造成早产,接下来计划观察500多名有早产风险的孕妇,以进一步探究其中的联系,这也将有助于开发预测女性早产的诊断工具以及帮助她们预防早产的新策略。
6、从动物粪便中萃取牲畜饮用水
美国密西根州立大学的研究有突破,欲从粪便中萃取饮水,水的洁净程度,给牲畜饮用,是绰绰有余。该项研究有望在今年内投入商业运用,这项技术对于水资源匮乏地区的畜牧业者,特别有价值。
报道称,密西根州立大学的研究团队,最先是运用微生物分离技术,从粪便中萃取能源和化学物质,后来,它们进一步透过超过滤、空气脱吸以及逆渗透技术,萃取粪便中的水份,水的洁净程度,给牲畜饮用,是绰绰有余。动物粪便中,有大约九成是水份,以密西根大学目前的技术,大概每100加仑(约合378.5升)的粪便,可以萃取到5加仑的水。
7、粪便移植逐渐为主流医学界接受
粪便移植为治疗很多疾病提供了新希望。但该领域的先驱者表示,还需要对它们进行更加科学地研究。
在担任荷兰阿姆斯特丹学术医学中心(AMC)内科医生之后不久,Max Nieuwdorp遇到了一个棘手的病例:一名81岁的女性因尿路感染引起的并发症而入院治疗。她有严重的褥疮,且高烧不退、无法进食。在抗生素已经消灭了病人的结肠微生物种群后,一种名为艰难梭菌的机会性致病菌入侵了她的身体,引起了严重腹泻和炎症性肠病。
成功案例
单单在美国,艰难梭菌这个“臭名昭著”的病原体在一年中已经至少使1.4万人丧命。治疗中,这名女性患者使用了几个疗程的万古霉素(这类病例中的常用抗生素)。但是,正如经常发生的一样,细菌产生了抗药性。
Nieuwdorp不甘眼睁睁地看着病人生命的流逝。“我很年轻和幼稚。”他说,并开始检索医学期刊数据库以寻找任何可以挽救病人生命的方法。当他找到1958年Ben Eiseman(当时是美国科罗拉多大学丹佛分校的内科医生)的论文时,他知道自己该如何做了。我打算采取粪便移植的治疗措施,Nieuwdorp告诉他的主管——Joep Bartelsman。
很快Bartelsman意识到Nieuwdorp并不是在开玩笑,他同意了Nieuwdorp的方案。治疗方案很简单:他们将对该病人进行结肠冲洗(希望借此也能清除艰难梭菌),并用来自捐赠者(她的儿子)的健康菌群替代。他们将她儿子的排泄物和盐水混合,通过插在鼻子上的一个薄塑料管,将混合物直接注射入病人的十二指肠。
治疗三天后,该病人出院了。Nieuwdorp和Bartelsman决定在接下来的几个月治疗另外6名艰难梭菌患者。由于这种不寻常的治疗会令人尴尬,他们都会等到同事们午饭休息时才开展工作。其中4名病人立刻痊愈,另外两人接受了来自第二名捐赠者的粪便移植。
但是,当Nieuwdorp将结果呈现在医院会议上时,一名内科医生提出了质疑:“如果你想通过粪便治疗艰难梭菌感染者,你为什么不把该方法也应用到心血管病人身上呢?”
类似的怀疑已成过去时。现在很多医生都同意艰难梭菌肠道感染能够通过粪便移植的方法治愈。研究人员还认为,这种大规模替代肠道微生物菌群的方法也有助于治疗其他疾病,例如炎症性肠病、糖尿病和难以捉摸的慢性疲劳综合征。越来越多的医生采用了粪便移植这种治疗措施。
Nieuwdorp说,现在仍缺失的是一个真正科学的方法来开展粪便移植。Nieuwdorp已经成为推广更多研究的主要倡导者。今年1月,AMC团队在《新英格兰医学杂志》(NEJM)上发表的文章描述了一个粪便移植的随机对照临床试验——这类研究首次被公开报道。Nieuwdorp还和其他实验室科学家开展合作,以更好地理解其作用机制。他希望,这些研究最终能帮助医生由粪便移植转为更精细的治疗手段:给病人注入选定的菌株。
成为主流
Eiseman开创性的论文发表在《外科学》杂志上,描述了用肛门灌注液状粪便的方法治愈了4名患假膜性小肠结肠炎的病人。(症状和艰难梭菌严重感染的病人相似,但可能由一种不同的细菌引起。)这不是首次在医疗中使用粪便,用粪便悬浮液治疗食物中毒和严重腹泻首次由中国医生于4世纪进行,到了17世纪,它们被用来治疗有肠道疾病的乳牛。
2010年,《纽约时报》刊登了一篇文章——美国明尼阿波里斯市明尼苏达大学医学中心的胃肠病学家Alexander Khoruts用粪便移植的方法成功治愈了一名艰难梭菌严重感染的患者,之后美国学界对粪便移植的研究兴趣愈发浓厚。Nieuwdorp说:“我意识到,为了让这个疗法能够被医生所接受,我们必须开展随机临床试验。”
随后的研究比较了粪便移植和万古霉素或万古霉素和肠道冲洗相结合的方式的疗效。研究人员选定了120名患者,但研究数据和安全监测在对43名病人进行试验后即终止,因为继续下去将不符合道德要求:94%接受粪便移植的患者得到治愈,相比而言,试验对照组的数据分别只有31%和23%。这一结果被发表在NEJM上,“这使粪便移植又向主流医学迈进了一步。”Khoruts说。
作用机制
了解粪便移植的作用原理是使治疗更加安全的关键。捐献者的粪便在术后会不会遗留在患者体内?哪一种细菌具有左右健康与疾病的能力?移植的微生物是如何与患者体内的微生物相互作用的?Nieuwdorp与荷兰瓦赫宁根大学微生物生态学家Willem de Vos(厌氧菌类的专家)展开合作,他们的团队是人类肠道领域研究的翘楚。de Vos说:“我们已经证明,一些重要的菌种在艰难梭菌患者体内丧失了,而另外一些有害的菌种大行其道。”他的研究还证明,艰难梭菌患者体内的微生物多样性程度仅仅与一名1岁大的儿童相当。但经过抑制治疗之后,来自捐赠者的厌氧性细菌会停留在患者的肠道内,帮助患者恢复微生物多样性。
Nieuwdorp的同事还包括瑞典哥德堡大学的Fredrik Backhed,Backhed管理着一座家鼠实验设施,那里的试验对象会在完全无菌的条件下生长,使科学家得以研究特定菌种的效果。Nieuwdorp说:“我们正在对不同的捐赠者进行试验,以便找出可以左右健康与疾病的超级细菌。”
实验的希望在于:医生最终能够控制这些细菌的排泄与灌输。但澳大利亚消化疾病中心的胃肠病学家Thomas Borody说,这种经过培养的钡灌肠可能会产生副作用,相比拥有完整生态系统的粪便,其治愈效果要低。并且随着在实验室中不断繁殖,细菌可能会发生变异,丧失治愈能力。
许多人仍然相信钡灌肠是行之有效的方法。最近,一个由日本东京大学Kenya Honda领导的小组报告:在治疗患有结肠炎和过敏性腹泻的老鼠的过程中,研究人员以17种无害的梭菌(曾被证明可以刺激免疫系统分泌调节T细胞)为治疗手段,有效地抑制了免疫反应过度。

在一项名为RePOOPulate的实验项目中,一个由加拿大金斯顿皇后大学的Elaine Petrof和圭尔夫大学的Emma Allen-Vercoe领导的研究小组,成功开发出一个由33个菌种组成的粪便装置,用于治疗艰难梭菌和炎症性肠病。他们希望这些菌种在为完整的粪便移植提供帮助的同时风险更小。Allen-Vercoe最初培养了70个菌种,Petrof以每一种菌种的致病性和抗生素抗性为依据,最终从中选出了33种。她说,在作最终选择的时候她依靠的是自己的判断力:“我会把这坨臭烘烘的东西塞进我妈妈的身体里吗?不会!那么我将把这个菌种剔除出去。”

一家名为Rebiotix的美国公司也是同道中人。最近,美国食品药品监督管理局放行了旨在治愈艰难梭菌的一项临床二期实验。Rebiotix公司的创立者兼CEO Lee Jones在一份邮件中写道:“我们并不认为本公司的产品是粪便移植,相反,我们正在开发的是一种基于生物医药形式的微生物修复治疗方法。”

Nieuwdorp认为这种治疗方法还存在多种可能性,但他认为要实现这些可能性需要时间。他说:“现在我36岁,如果到我60岁的时候微生物群分析可以成为医院实验室的标准程序,我将感到非常开心。”目前,粪便移植的禁忌已经不复存在,Nieuwdorp对此感到非常开心。
8、肠促胰岛素类药物不增加急性胰腺炎风险
针对糖尿病现有的治疗情况,比如胰岛β细胞功能不断衰竭、患者血糖水平持续升高、降糖药物可能增加低血糖风险和患者体重增加以及继发性药物失效等问题,基于肠促胰岛素的治疗方案应运而生。

肠促胰岛素是人体在进食后,肠道细胞分泌的一些多肽类激素,其作用是增加胰岛素的分泌,以维持血糖正常,好比血糖的内源性“调节器”,只有在血糖升高的时候,才会刺激胰岛素分泌。

胰升糖素样肽-1(GLP-1)类似物和二肽基肽酶4(DPP-4)是新一代抗糖尿病药物。而肠促胰岛素类药物是否会引起急性胰腺炎仍没有一致的研究结果。

鉴于肠促胰岛素类药物使用人数不断上升,并出于对这类药物安全性方面的担忧,来自加拿大犹太总医院临床流行病学中心的Faillie等进行了一项研究,探讨肠促胰岛素类药物是否会增加急性胰腺炎风险。

该研究是一项以人口为基础的队列研究,研究数据来自英国临床研究数据链中680家全科诊所。从2007年1月1日到2012年3月31日期间,Faillie等对20748例肠促胰岛素类药物使用者与51712例磺酰脲类降糖药使用者进行比较,并随访至2013年3月31日。采用Cox比例风险模型评估肠促胰岛素类药物与磺酰脲类药物使用者的急性胰腺炎风险比。

结果显示,肠促胰岛素类药物使用者的急性胰腺炎发生率为1.45/1000人年,而磺酰脲类药物使用者为1.47/1000人年。相对磺酰脲类而言,肠促胰岛素类药物并不增加急性胰腺炎风险。

该研究提示,与磺酰脲类相比,肠促胰岛素类药物不增加急性胰腺炎风险。Faillie指出,虽然这一研究结果让人们对肠促胰岛素类药物放心,但仍不能排除风险轻微升高,因此仍需要更多的研究来证实。

目前,已在我国上市的GLP-1类似物有:艾塞那肽注射液(百泌达)、利拉鲁肽注射液(诺和力)等;DPP-4抑制剂已上市的有:西格列汀(捷诺维)、沙格列汀(安丽泽)、维格列汀(佳维乐)等