PMN apoptosis and its relationship with the lung injury after chest impact trauma / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Polymorphonuclear neutrophil (PMN), one of the most important inflammatory cells, functions throughout the initiation, progression and resolution of inflammation. This study aimed at investigating the relationship between PMN apoptosis and the lung injury after chest impact trauma.</p><p><b>METHODS</b>PMNs were purified from rabbits subjected to the chest impact trauma and their apoptosis, necrosis, survival and respiratory burst were detected by flow cytometry. Meanwhile, lactate dehydrogenase and (LDH) [Ca2+]i were measured.</p><p><b>RESULTS</b>The delayed apoptosis of PMNs in bronchoalveolar lavage fluid was observed from 2 hours to 12 hours after trauma, and viable cells increased. Respiratory burst of PMNs in bronchoalveolar lavage fluid was increased significantly from 2 hours with the peak at 8 hours. Meanwhile, lactate dehydrogenase in bronchoalveolar lavage fluid was higher than that in control (P < 0.05) from 4 hours to 24 hours, and intracellular free Ca2+ in PMN was increased temporarily.</p><p><b>CONCLUSIONS</b>Retention of PMN in tissues and the abnormality in apoptotic pathway inevitably generate persistent activation of PMN and excessive release of toxic substances, resulting in tissue injury. The temporary increase of intracellular free Ca2+ may be responsible for the delayed apoptosis of PMN.</p>

mtDNA mutations in mouse tumors / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate variations of mtDNA in mouse tumors and to explore the relationship between mtDNA mutations and murine carcinogenesis.</p><p><b>METHODS</b>Variations of D-loop, ND3 and tRNAIle + Glu + Met gene fragments of mtDNA from six mouse tumor cell lines were analyzed by PCR-RFLP and PCR-SSCP techniques.</p><p><b>RESULTS</b>ND3 and tRNAIle + Glu + Met gene fragments of mtDNA from the tumors showed no variations at 27 endonuclease sites. The D-loop of mtDNA from Hca-F demonstrated an additional endonuclease site of Hinf I in contrast to the inbred mouse. Upon PCR-SSCP analysis, the D-loop of mtDNA was found to possess mutations in 4 of 6 tumors.</p><p><b>CONCLUSION</b>D-loop appears to be the hot spot for tumor mtDNA mutations, which may contribute to the carcinogenesis of murine tumors.</p>