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Animal Model And Mechanism Of Death By Externally Mechanical Force Hitting Carotid Sinus Baroreceptor

Posted on:2006-07-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:J B LiFull Text:PDF
GTID:1116360155451111Subject:Surgery
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Objective: It was considered that there was some relation with carotid sinus baroreceptor (CSB) of reporting that unknown cause syncope in clinic at sometimes. There were some death reports caused by stimulating cervical part in clinic and forensic medicine. till now the death mechanism was not clear, which had typical symptom,but no morphological evidence. To explore death mechanism, index and standard for diagnose death, death model of animal was set up using external mechanical force hit rabbit's CSB, the technique of physiology, morphologic, biochemistry of blood serum, and molecular biology were applied for the concentration measurement of atrial natriuretic polypeptide (ANP), Nitric Oxide (NO) and Nitric Oxide Syntheses (NOS), and the expression of ANP mRNA and NOS mRNA and so on. Materials, Methods and Results: 1.Physiological Index :Observation of physiological index about using external mechanical force hit rabbit's CSB (n=20). Heart rates were descend and die part of animals about 25%(5/20), and heart rates descend in begin in some animals (75%) (15/20), later on heart rats and blood pressure (BP) increase or normal. It was indicated that the key factor of death was BP significantly descend after CSB was beated, as the same time collate group and injuries group were set up ( n1=n2=8). 2. Morphological Study: There was not lethal morphological evidence in apparatus with death animals, the death reason was mechanical external force bit rabbit's CSB. Observation of morphological evidence in death groups: adventitia carotid sinus (CS) was injured, including slice haemorrhage, nerve fiber broke and nerve fiber axis plasma dissolved, but no significantly pulmonary edema changed. Acute myocardium ischemia changed. ANP significantly descend or vanished in right atrium. Survival groups less than death groups in acute myocardium ischemia, but ANP in right atrium was more. It was indicated that CS was injured, acute myocardium ischemia changed and ANP significantly descended or vanished in right atrium after mechanical external force bit rabbit's CSB, leading to death cause BP descend and acute heart failure. 3. Blood Serum ANP Detectation: There was no significantly different outcome of ANP in blood serum detected radio-immunity technique among death groups (n=5), survival groups (n=15) and injury groups (n=8) before experimented (P>0.05), Their datas(X+S) were 195.39±13.15, 169.68±28.72, 157.74±31.64 pg/mL in groups repectively. It was significant different outcome of ANP in before and after experimented in death groups (P<0.01), its datas was 657.19±185.82 pg/mL and increased 3 times in death groups. It was obviously different outcome of ANP in death groups, survival groups and injury groups after experimented (P<0.01). It was not significant different outcome of ANP in survival groups and injury groups after experimented (P>0.05). It was indicated that the concentration of ANP in blood serum was important effect in investigate death mechanism. 4. NO and NOS Detectation: Concentration of NO measured by spectrophotmeter technique in same groups, were (X±S) 84.51±10.78, 78.51±59.31, 72.08±12.16μmol/L before experimented, There were no significantly difference (P>0.05). Furthermore, no great difference before and after experimented (P>0.05), only the gently increase in death groups. There were no great difference in before and after experimented withsurvival groups and injury groups (P>0.05), but the concentration of NO gently descend. They were not significant difference in groups after experimented (P>0.05).They were significant different dispersion of before and after experimented among death groups, survival groups and injury groups (P<0.05). The concentration of NOS changes be similar to concentration of NO. It was indicated that injury stress may inhibited activity of NOS and synthesis NO descend. Concentration of NOS and NO gently increase in death groups, It could be explained that cause that shock may to continue after mechanical external force bit rabbit's CSB. NOS and NO brough on BP...
Keywords/Search Tags:carotid sinus baroreceptor (CSB), death model, morphological evidence, atrial natriuretic polypeptide (ANP), Nitric oxide (NO), Nitric Oxide Synthase (NOS)
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