| Leukemia is the most common malignant blood disease, and its morbidity was2.76/100000in China while its mortality ranked the sixth among men and the eighth among women in all malignant tumors. Gastric cancer is one of the most common tumors and its mortality ranked the second among all tumors worldwide. Gastric cancer ranked the fourth in all newly diagnosed cancer cases each year, which was second to lung cancer, breast cancer and colon cancer. About800000persons were diagnosed as gastric cancer while750000patients were died from it annually.As leukemia and gastric cancer do serious harm to human beings’ health, it is of great importance to diagnose them at early stage. In recent years, IR spectroscopy has been developed as a new method to investigate diseases at molecular level. IR spectroscopy contains abundant information about molecular structures and can probe structural changes sensitively. Since IR spectroscopy has advantages such as high sensitivity, preparing specimens easily and testing samples non-destructively, it can study cancer cells and tissues at the molecular level. Since the first application of IR spectroscopy on medical research in the1980s, it has been widely used in biomedical field.In this doctoral dissertation, the leukemia and gastric cancer were investigated by IR spectroscopy and the following studies were carried out:1Comparing the serum and fingernails of leukemia patients with those of healthy persons to explore the differences between them;2Comparing serum of①gastric cancer patients with that of healthy persons,②pre-operative and post-operative gastric cancer patients to explore the differences between them;3. Comparing erythrocyte of pre-operative and post-operative gastric cancer patients to explore the differences between them;4Analyzing the gastric cancer cell lines and normal gastric cell lines by focal plane array (FPA) to understand the gastric cancer pathogenesis further. The following results were obtained:(1) The ratios of H2959/H2931(methyl/methylene) and A1115/A1028(RNA/DNA) were different between leukemia patients and healthy persons, which could be used to identify the leukemia patients from healthy persons.(2) IR spectra of fingernails showed’the keratin and nucleic acid contents of leukemia patients increased gradually, indicating that leukemia could lead to the changes of the phosphodiester structures,(3) The ratios of H2959/H2931and RNA/DNA were different between serum of gastric cancer patients and healthy persons, which indicated that the serum of healthy persons contained shorter and/or more branched chains of lipids than that of gastric cancer patients.(4) The corresponding components of gastric cancer patients’serum were changed after surgery, which suggested that IR spectroscopy might be used to monitor the curative effect of operation for gastric cancer patients.(5) The ratios of A1543/A1085of red blood cells decreased after operation, which indicated that the relative content of ribosomal/nucleic acids of RBCs were higher in post-operative gastric cancer patients.(6) The FPA results showed:①the ratios of H1121/H1020(RNA/DNA) of SGC7901and BGC823cells were higher than that of GES1cells with tumor becoming malignant,②the strongest absorption of DNA, protein and lipids were all found in in the nucleus of gastric cells.The above studies showed that IR spectroscopy and imaging may play an important role in biomedical field. Those studies might be helpful to elucidate cancer pathogenesis and be useful for cancer diagnosis, which would provide basis for the application of IR spectroscopy and imaging in cancer research. |
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