重金屬錯影響細胞生理功能的研究
儘管鍺在電子工業上被廣泛運用,但對於暴露在鍺化合物所產生的毒害則尚未被詳細的探討。在探討鍺對細胞所產生的生理影響中,我們使用了二氧化鍺 ( GeO2)和有機鍺( Ge-132 )。由實驗結果顯示, GeO2,會造成人類子宮上皮癌細胞( A 431 ) 及巨噬細胞株( Raw264.7 )死亡,而 Ge -132 對細胞生長則不造成任何影響,為了進一步了解鍺引起細胞死亡是否是經過細胞凋亡(apoptosis ) ,我們將鍺處理過的細胞進行染色體 D NA 的分析,結果發現細胞中 DNA 染色體沒有斷裂。由先前 Huang 等人於 1999 年的研究結果顯示,砷對細胞所造成的毒性是經由有絲分裂活化酵素( MAPK )傳導路徑,所以為了解鍺誘導細胞死亡的路徑,我們亦分析 MAPK 傳導路徑是否亦參與其中,我們發現 GeO2加入 A431 細胞後,會活化有絲分裂活化酵素中的 ERK ,但對JNK 及 p38 皆無影響,在對蛋白質表現方面,轉錄因子 c-Jun 的蛋白質表現也是隨著GeO2加入的時間增加而上升。 GeO2加入 Raw 264 . 7cell 後,會造成 JNK 、 ERK 的活化,同樣的轉錄因子 c- Jun 也會增加,由此一結果得知鍺對細胞的影響會因細胞的不同而有所差異,為了分析自由基是否參與砷及鍺所造成細胞死亡的過程,我們分析在 A431 細胞中可產生的 NO 的可誘導性 nitric oxide synthase ( iNOS )的表現,我們發現氧化鍺及砷都會誘導 iNOS 的表現量增加。綜合以上結果,可能顯示氧化錯可能會經由 M A PK 訊息傳遞路徑來促使細胞的死亡,並且 iNOS 亦可能參與此過程。就我們所知,這是第一個提出重金屬所造成的毒害可能會經由 iNOS 來誘導產生的研究。
Despite the extensive use of germanium (Ge) in the electronic industry and optical devices, the potential risks of exposure to germanium compounds have not been evaluated. The effects of germanium on cell physiological functions were studied. We first asked if germanium oxide (GeO2) or carboxyethylgermanium (Ge-l32) could affect cell viability. We found that GeO2, but not Ge-l32, reduced cell viability in a dose-dependent manner in epidermoid carcinoma A43 I and macrophage Raw 264.7 cells. In order to test whether apoptosis contributes to germanium cytotoxicity, DNA fragmentation was evaluated in A43 1 and Raw 264.7 cells treated with GeO2 or Ge-132, respectively. We found that neither GeO2 nor Ge- 132 had effect on chromosomal DNA fragmentation. Previous studies by Huang (1999) et al indicated that sodium arsenite (NaAsO2) cytotoxicity is mediated through mitogen-activated protein kinase (MAPK) pathways. In order to study the mechanism(s) by which GeO2 mediates cell death, we analyzed the signal transduction pathways triggered by GeO2 We found that GeO2 stimulated the extracellular signal-regulated kinase (ERK) activity and transcription factor c-Jun in a time-dependent manner, but not c-Jun amino-terminal kinasc (JNK), or p38 MAPK in A431 cells. Treatment of the Raw 264.7 cells with GeO2, induced activities of ERK, JNK and c-Jun in a time-dependent manner. Collectively, these results suggested that GeO2 effects might be cell type specific. To test whether free radicals were involved in NaAsO2 or GeO2 mediated cell death, the expression of inducible nitric oxide synthase (iNOS), which produced the NO free radical, was determined in A431 cells treated with NaAsO2 or GeO2. We found that expression of iNOS was induced in a time-dependent manner in NaAsO2 or GeO2-treted A431 cells. Taken together, our results indicated that GeO2-induccd cell death may be mediated through MAPK signal pathways and that iNOS may contribute to NaAsO2 or GeO2 mediated cell death. To our knowledge, this is the first report that iNOS may contribute to heavy metal mediated cytotoxicity.
聽音辨位--聲波的測量應用
本實驗設計主要是以波的傳送速度(特別是聲波),以及接收收到的時間值來做實驗、運算、討論。而其特點是為了應用於實際生活中,做了許多異於平常測量方法的設計。主要是使用時間差(|t1–t2|V=發聲器到兩感應器的距離差 )來消彌掉一般測量時,需要採取同步的條件,說明如下:
1. 由以上的圖中,t1’ = T + t1 為實際由感應器開始感應到感應器#1 接收到訊號的時間;同理,t2’ = T + t2 為實際由開始感應到感應器#2 接收到訊號的時間。而T 為感應器開始感應到發聲器開始發聲的的時間(之後的 T 皆為如此)。由以下式子得知:
|t1’ - t2’|=|( T + t1 ) - ( T + t2 ) |=|t1 - t2|及為本實驗所需的時間差。利用減法將T 消除,便及為發聲器與感應器不必採取同步,此為本實驗目標以及優點之一。
2. 之後的公式推導中,實際由感應器開始感應到感應器接收到訊號的時間中,表示為t1、t2、t3……以此類推。
像是市面上販售的反射式測距器由於其直線性的限制,在我們可負擔的情況下,就只能做一維的測量,而在本實驗中,我們使用多個感應器,而可測量至二、三維空間,並使測出的物體由相對位置轉為絕對位置。再加上正在計劃中的測量儀器改良與自製,例如利用電腦的音效卡接上麥克風或是其他感測器,以及電子零件、電路的組合與設計。而在於一般的實際應用面上可配合工業的破壞性檢測,甚至是橋樑的斷裂處、各種振源的測量,亦或是人員的搶救,都應有不錯的效果與利用價值。
1.The major design of experiment is to spot the location of an object by experiment, calculating and discussing of such figures like the transmission speed of the waver (especially sound wave), plus time value of the receptor and so on to get the result. 2.In practice, the ordinary measuring method has to be implemented under the circumstance of synchrony: however, the distinguishing characteristic in the experiment is to overcome such restriction with the use of the “time lapse” concept. 3.The reflecting measuring instrument on the market is limited by its “straight-line characteristic.” Instead, we use multiple sensors to spot the absolute location of an object in its 1-D, 2-D, 3-D form. 4.We have now been working on the improvements of the measuring instruments, for instance, using sound cards to connect to the microphone to make a new sensor; also, the redesign and combination of other electric parts and circuits are also under construction. 5. We plan to apply the experiment not only in spotting the location of an object but also in further spotting the location of vibration coming from various objects (e.g. in the use of rescue).