| IntroductionIt is commonly accepted that Mulliken have categorized vascular birthmarks as hemangriomas or vascular malformations based on their clinical behavior and endothelial cell characteristics. The term hemangioma /angioma is restricted to the very common vascular lesion of infancy that usually appears 2 to 4 week after birth. It grows rapidly until the age of 6 to 8 months, and then slowly, predictably, and spontaneously involutes by more than one year. On a cellular level, hemangiomas are characterized by increased endothelial turnover and creased numbers of mast cells during their rapid postnatal growth phase. Involuted hemangiomas have diminished cellularity with fibrous tissue, and have low mast cell counts. Vascular malformations are present at birth, although many do not become clinically obvious until late infancy or childhood. They grow commensurately with the patient, trauma, infection, or endocrine changes may effect increases in size. They do not have a tendency to involute and on a cellular level are characterized by a normal endothelial cycle and normal numbers of mast cells throughout their natural history. Whether hemangioma or malforma-tion, these vascular lesions represent the most common growths of infancy and childhood in the head and neck region, and may have an in fluence on the various Function of the boby. Althought it is benign tumor, especial hemangioma, it has the characteristics and clinical behavior of the same malignant tumor, which is studied hardly.As a mediator, messenger and regulator, nitric oxide (NO) is a multifunctional molecule that is implicated in various processes of physiology and pathology, including neurotransmission, immune defense, cytotoxicity, genetic regulation and so on. The role of NO in tumor pathological process, however, is poorly understood. Some investigators named NO a " double - edged sword" because it has both inhibitory and tumor promoting activities. NO has a very complicated role in tumor pathological process.To directly detect NO is very difficult because it is a free radical small molecule and a short - lived substance with active property, therefore, the description of localization and expression of NOS in tumor has been regarded as one of the methods which assess the biological action of NOS in the tumor process at present. Based on calcium dependence, three different NOS isoforms have been identified in human tissue: endothelial NOS (eNOS), neuronal NOS (nNOS), both of which are calcium dependent, and inducible NOS (iNOS) , which are calcium independent. iNOS do not express under physiological conditions, but it can be activated under pathological conditions by many cytokines (i. e. IL-126, TNF - a, IFN - r and LPS) , and produce amount of NO for many hours or even days once it has been induced.To data, it has been reports that iNOS can be expressed in various human solid tumor. Implicated in the process of carcinogenesis invarious organs, however, there are fewer documents on the localization and expression of iNOS in oral and maxillofacial tumor, only fewer reports about squamous cell carcinoma. As far As we are unware there is a report concerning the localization and expression of iNOS in benign tumor or hemangioma.The present study aims to find out immunohistorchemically the characterization of localization and expression of iNOS in hemangioma, the phases of hemangioma, and vascular malformation, meanwhile , to research for the relationship between those and NO/iNOS. If it is proved by the laboratory, the biological activities of iNOS in the phases of hemangioma will be assessed.Materials and AgentsMaterials: 57 specimens resected in department of oral and maxillofacial surgery were collected in the Second Clinic College of China Medical University from 1998 -2000, which were of body surface of vascular leisions of infancy or childhood who was from 10 days to 15 years age, Of 57 specimens, 49 with hemangiomas, which were 32 of the proliferative phase -the early 11(0 -2months) Nthe mid 13(3 -6month... |
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