| 摘要: | 人類中的腎結石是非常常見的生物礦化例子。全世界有5%的人口受腎石所苦。在人體中，有不同種類腎結石: 如含鈣腎結石，鳥糞腎結石（六水磷酸銨鎂水合物），尿酸腎結石，以及其他腎結石（胱氨酸，黃嘌呤等），但又以含鈣腎結石最常發生在人體中。含鈣腎結石是由主要成分的草酸鈣和次要成分的磷酸鈣所組成。而尿酸在腎結石組成中，是一個主要的有機物質。經過廣泛文獻閱覽後，在腎結石的形成，許多人們都把焦點放在草酸鈣結晶。相對而言，很少研究調查磷酸鈣結晶。因此，在本文中，主要有三個重要的目標來找出在人體中，腎結石於初始狀態中的形成機制。第一，利用反溶劑法來建立尿酸的工程資料庫，如：溶解度，晶體外貌和多型晶體。第二，清楚地辨別不同的草酸鈣水合物。第三，利用模仿尿液篩選實驗和流量實驗，找出是什麼因素於在初始狀態中，導致腎石形成。藉著利用這些資料可以更明確的加以了解腎結石在人體中的起因。除此之外，我們還發現： （1）在文獻中針對高鈣尿症和雙水草酸鈣的簡單關聯，有待對雙水草酸鈣水合物在人體內的形成，有更進一步的了解。 （2）鎂離子可減少雙水草酸鈣晶體的形成，誘發和形成穩定的二水磷酸氫鈣。 （3）檸檬酸會與鈣鍵結而形成可溶性錯合物，因此，減少自由的鈣離子而減少草酸鈣形成。 （4）非晶型磷酸鈣、草酸鈣單水合物和雙水磷酸氫鈣水合物會做為基板，在之後的階段，單水草酸鈣水合物，雙水磷酸氫鈣水合物和羥基磷灰石於基板上以緩慢生長成球晶，並且非晶型磷酸鈣、草酸鈣單水合物和雙水磷酸氫鈣水合物最終成為腎結石的核心。 （5）雙水磷酸氫鈣水合物和非晶型磷酸鈣在短時間內，可以很容易地成長到約50微米的聚集體，因此磷酸鈣在生理的重要性應該比草酸鈣更值得關注！ Renal stone in humans is a very commonly seen example of biomineralization. It affects up to 5 percent of the population of the world. Various types of renal stones occur in humans: calcium-containing stone, struvite (magnesium ammonium phosphate hexahydrate) stone, uric acid stone, and other (cystine, xanthine, etc) stone, but calcium-containing stone are the most common in humans. Calcium-containing stone are composed of calcium oxalate as the major form and calcium phosphate as the minor form. Uric acid is also a dominant organic material in renal stone composition. After studying an extensive of references, in renal stone formation much attention has been paid to the crystallization of calcium oxalate. Relatively few studies have investigated the crystallization of calcium phosphate. So, three important goals in this thesis are performed to find out the mechanism of renal stone formation in the initial state in humans. Firstly, an engineering data bank of solubility, crystal habits and polymorphism by anti-solvent for uric acid was established. Secondly, calcium oxalate phases was clearly distinguished. Thirdly, using urine-like screening experiments and flow experiments found out what factors cause the renal stone formation in the initial state. By answering these questions, we will more specific understand biomineration in humans. Besides, we also found: (1) A simple direct association between hypercalciuria and COD in the literature might have only told part of the story until the conditions that produced COD in vivo were better understood. (2) Magnesium ions could minimize the formation of COD crystals, induce and stabilize the formation of dicalcium phosphate dihydrate or brushite (DCPD). (3) Citrate was bound to calcium to form a soluble complex, therefore, decreased available free calcium ions for calcium oxalate formation. (4) ACP, COM and DCPD would then serve as a substrate for the relatively slow layered spherulitic growth of COM, DCPD and hydroxyapatite in a later stage and eventually became the kernel of a urinary stone. (5) The physiological importance of the calcium phosphate phase should deserve more attentions than calcium oxalate since DCPD and ACP could easily grow into large clusters of about 50 μm within a short period of time! |
