The Role Of Human Platelet Phospholipase A₂ In Host Defense Bacteria Infection And Relationship Of Human Platelet Phospholipase A₂ And Hepatocarcinoma

Objective: To explore the role of human platelet phospholipase A2(PLA2) in host defense bacteria infection and the relationship between platelet PLA2 and hepatocarcinoma. To study the platelet PLA2 cDNA and amino acid sequence of Chinese, to get further understand of platelet PLA2. Methods: 1. We determined the plasma bactericidal activity of patients with bacteria infection against Staphylococcus aureus (S.aureus) . The level of platelet PLA2 mRNA were measured by using reverse transcription polymerase chain reaction(RT-PCR). 2. The platelet rich plasma of rat and human were stimutated by thrombin, then compared the bactericidal activity. The level of platelet PLA2 mRNA of them in blood was determined. 3. The platelet PLA2 mRNA of 10 hepatocarcinoma patients were measured by using RT-PCR, to compare the PLA2 mRNA level between of tumor tissues and neighboring liver tissues. 4. Platelet PLA2 cDNA were cloned from hepatocarcinoma tissue and neighboring liver tissues of Chinese and DNA sequnces were determined. To observe whether there was any mutation. 5. A comparison of nucleotide sequences was made between known platelet PLA2 gene data of foreigner and PLA2 cDNA were found, to observe whether there wassignificant divergence of platelet PLA2 between different race. Results: 1. The plasma of patients with bacteria infection possessed a potent bactericidal activity towards S.aureus and the activity was related to platelet PLA2. The level of platelet PLA2 mRNA in blood were significantly higher than health people's. 2. The platelet rich plasma of human hadn t any bactericidal activities after treated with thrombin, but it could be observed in rat. 3. The sequence of platelet PLA2 cDNA was no significant difference between foreigner and Chinese of Han nationality and Zhuang nationality. 4. Comparing platelet PLA2 mRNA level of tumor tissues and neighboring liver tissues, there was no regular pattern. 5. Analyzed platelet PLA2 cDNA cloned from 3 hepatocarcinoma tissue, it was no significance meaning mutation. Conclusion: 1. Human platelet PLA2 play an important role in bacteria infection disease. 2. Human platelet stimulated by thrombin has no obviously bactericidal activity. 3. The sequence of the human platelet PLA2 DNA come from different races is highly conserve. 4. There was no regularity in mRNA level of platelet PLA2 in tumor tissues and neighboring liver tissues. 5. The DNA sequence of human platelet PLA2 from hepatocarcinoma tissue has no significant meaning mutation.