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科研中的巧可補缺

巧妙思路可以彌補技術的缺乏

開展科研工作時,我們經??嘤趯嶒灄l件無法滿足需要,難以清楚回答自己選擇的問題,也就是說存在許多難以實現的科研思路,但如果能在巧妙上多下一些功夫,也能夠開展很不錯的研究,甚至對解決實際問題有更大幫助。

我一直覺得,開展轉化醫學研究的人總是把眼睛盯著細胞學機制的研究不是正確的道路,要解決實際問題不見得一定采用特別高的技術,越是簡單的技術手段,如果發揮地好,距離解決問題越近,因為簡單的技術在應用上更容易被應用。下面我以一篇剛看到發表在Journal of Neurotrauma上的文章,嘗試說明這個問題。

這是一個關于腦創傷的研究,研究的目的是看血液中的非細胞成分DNA水平和腦創傷的關系。DNA在正常情況下只存在細胞內,當身體有細胞發生壞死的時候,由于細胞內的DNA發生斷裂,變成小片斷,細胞內的小片斷DNA可以擴散到組織周圍細胞外,也有一些擴散到血管內進入循環系統。

作者用了39只大鼠(夠少的),將動物分成假手術和模型兩組(夠少夠簡單的),用打擊法,就是用重物擊打腦組織,制備成彌散性腦損傷模型(經典但粗糙的模型)。模型作好后1小時、24小時、48小時進行神經行為學評價,就是根據動物的運動和感覺反射等方面的行為表現來判斷神經系統功能受到傷害的程度,這是非常常用的不是非常穩定的方法,但不影響其他研究內容。一般開展神經系統損傷的實驗室都玩這個東西。在模型0小時(模型前為基數)、12、24、48、72、120小時(5天)分別取動物血液進行非細胞成分DNA水平檢測。在48小時的時候,11只動物(每組?)處死后取腦組織,進行腦水腫檢測,怎么檢測?就是把腦組織稱重量,然后用100度烤箱烤成干,再稱重量,兩者差就是水的重量,水重在腦組織中的比例就是腦組織含水量,當發生腦水腫的時候,可以從78%左右上升到82-83%左右。這個是經典的腦水腫檢測方法(夠簡單)。檢測的結果發現,腦創傷后24和48小時,血液中的非細胞成分DNA水平明顯增加,其中24小時的增加和48小時腦水腫以及其他時間的行為學改變存在相關性。這個研究給臨床上提供了一種快速簡單有效的可以用血液中成分分析腦損傷的方法??傊?,作者用了很少的材料,很簡單的技術,完成了一個很不錯的研究。盡管初步,但新穎且具有啟發性。

后評:

1)我們可以借助這個思路開展其他類型疾病的研究,當然思路沒有那么巧妙了,當仍有意義。

2)更值得的是,可以用這個方法結合臨床,采用這個指標研究是否真的具有診斷價值,建立診斷標準,推廣到臨床上。

3)胡亂猜想的,不同類型組織是否存在不同的DNA,似乎不是,因為理論上所有細胞的DNA序列都一樣的,不過不同壽命的細胞可能存在不同程度的DNA修飾或突變。如果能開展不同組織類型DNA特點的研究,可以在將來把這種手段開發成靶器官的診斷。

4)當然這種研究仍存在很大不足,這種非細胞DNA也可以從炎癥細胞釋放,不一定從損傷的組織。

5)細胞外DNA已經被認為屬于損傷模式分子,也就是說可以引起免疫反應,這種改變也類似于炎癥反應分子的一種特殊類型。那么本類研究更應該檢測炎癥反應的程度,并進行相關分析。

Journal of Neurotrauma

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Cell-Free DNA as a Marker for Prediction of Brain Damage in Traumatic Brain Injury in Rats

To cite this article:

Sharon Ohayon, Matthew Boyko, Amit Saad, Amos Douvdevani, Benjamin F. Gruenbaum, Israel Melamed, Yoram Shapira, Vivian I. Teichberg, and Alexander Zlotnik. Journal of Neurotrauma. January 20, 2012, 29(2): 261-267. doi:10.1089/neu.2011.1938.

Published in Volume: 29 Issue 2: January 30, 2012

Online Ahead of Print: December 7, 2011

Full Text HTML Full Text PDF (182.1 KB)Full Text PDF with Links (162.7 KB) Author information

Sharon Ohayon,1*

*The first two authors contributed equally to this article.

Abstract

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, and early predictors of neurological outcomes are of great clinical importance. Cell free DNA (CFD), a biomarker used for the diagnosis and monitoring of several diseases, has been implicated as a possible prognostic indicator after TBI. The purpose of this study was to determine the pattern and timing of CFD levels after TBI, and whether a relationship exists between the level of CFD and brain edema and neurological outcomes. Thirty-nine Sprague–Dawley rats were randomly assigned to two groups: rats in group 1 (sham group) were anesthetized and had a scalp incision without TBI, and rats in group 2 were anesthetized and had a scalp incision with TBI, which was induced by using a weight drop model that causes diffuse brain injury. A neurological severity score (NSS) was assessed at 1, 24, and 48h after TBI. CFD was measured via blood samples drawn at t=0 (baseline), 12, 24, 48, 72, and 120h after TBI. At 48h after TBI, brain edema was determined in a subgroup of 11 rats by calculating the difference between rats' wet and dry brain weight. The significance of comparisons between and within groups (CFD levels, brain water content, and NSS) were determined using the Kruskal–Wallis, Mann–Whitney and Student t test. The correlation between CFD levels and the NSS, as well as between CFD levels and the extent of brain edema, was calculated using the Spearman and Pearson tests, respectively. Compared with baseline levels, the CFD levels in rats subjected to TBI were significantly increased at 24 and 48h after TBI (p<0.01 and p<0.05, respectively). A positive correlation was demonstrated between CFD levels 24h following TBI and the extent of brain edema (r=0.63, p<0.05), as well as between CFD levels and the NSS (r=0.79, p<0.005). In this study, we demonstrated an increase in CFD levels after TBI, as well as a correlation between CFD levels and brain edema and NSS. CFD levels may provide a quick, reliable, and simple prognostic indicator of neurological outcome in animals after TBI. Its role in humans has not been clearly elucidated, but has potentially significant clinical implications.

 

本博他山之石欄目都是一些名家博客采集而來,不代表本博言論。僅是一個方便大家交流學習的平臺。歡迎大家踴躍來稿。

本文引用地址:
http://blog.sciencenet.cn/blog-41174-540392.html

 

 
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