| Background: Sudden death(SD),refers to unexpected,non-violent sudden death that occurs naturally within 24 hours.Sudden cardiac death(SCD)is the most common cause of sudden adult death,which usually occurs within one hour after the onset of symptoms,without any warning.The most common cause of SCD is coronary heart disease(CHD),followed by cardiomyopathy,myocarditis,valvular disease and channel disease.Sometime,it's difficult to determine the cases of SD due to myocardial ischemia within 6 hours.Irreversible changes of myocardial cells occur after ischemia.Morphological changes occur at least six hours after ischemia and hypoxia or later,such as eosinophilic degeneration,granular degeneration,wavy changes of cardiac fibers,nuclear shrinkage,necrosis of contractile zone,myocardial can be seen coagulation necrosis and inflammatory cell infiltration of cardiomyocytes.However,in the actual cases of forensic pathology,most sudden deaths usually occur within 1-6 hours of myocardial ischemia and hypoxia,and there is no significant predisposing factors before death,or lack of visual or valid witnesses at the scene,makes it great difficulty to determine the cause of death legally.Some auxiliary detection means and methods are needed.To provide the basis for ischemic myocardial lesion,so as to clarify the cause of death.Histochemical and immunohistochemical techniques have become the focus of domestic and foreign experts because of their simple operation,good sensitivity and specificity.Studies have shown that histochemical and immunohistochemical methods may be a good experimental tool for early myocardial ischemia fatality diagnosis and judging the time of ischemic myocardial injury.In fact,inflammatory molecules such as complements,inflammatory mediators,cardiomyocyte proteins,plasma proteins,stressor hypoxia-inducible factors and proteins associated with heart failure can be evaluated by histochemical or immunohistochemical methods.To this end,the purpose of this study is to apply histochemical and immunohistochemical methods to detect sudden death myocardial tissue and explore its sensitivity,specificity and practical application value in early myocardial infarction tissue,eventually find a suitable detection method for the diagnosis of early myocardial infarction.Part one: Clinical Analysis of 110 Cases of Sudden Death in Dianxi.Objective: To analyze the etiology and clinical characteristics of 110 cases of sudden death(SD)and explore the characteristic and the cause of sudden death,finally provide a basis for the prevention and treatment of such diseases.Methods: Materials: We investigated 110 cases of SD from 2010 to 2017 at Dali Dianxi Judicial Expertise Center and the First Affiliated Hospital of Dali University.All cases were treated by systematic anatomy,histological examination and IgE examination,these factors were excluded from the analyses such trauma,poisoning,drug allergy,electric shock,high and low temperature,asphyxia and so on.(1)SD: All cases were diagnosed according to the World Health Organization classification.(2)SCD: To confirm the diagnosis of the fatal lesions in the cardiovascular system.(3)SD from other systemic diseases: the autopsy confirms that the fatal lesions were caused by other systemic diseases,such as Central nervous system,respiratory system,digestive system,etc.Results: Among the110 cases,SD often occurred in young and middle-aged males with the median age of44.5,accounting for 65.5%.55 cases(50.0%)died of SCD,in which CHD was the most common cause;55 deaths(50.0%)were caused by other systemic diseases and the most frequent cause was respiratory systemic diseases.Conclusion: SCD is the largest cause of sudden death with coronary heart disease as the most common cause.Besides,SD caused by respiratory systemic diseases takes the second place and the most frequent cause of such death results from pulmonary diseases.Part two: To investigate the detection methods of early myocardial infarction and its application value.Objective: To explore the sensitivity of early ischemic myocardial detection methods.1.Materials: Myocardial specimens were collected from 20 cases of sudden cardiac death and 10 cases of non-sudden cardiac death.They were left ventricular wall,septum and apex,respectively.2.Methods:(1)Using HBFP staining,chromotropic acid2R-bright green staining and Heidenhain staining for myocardial Specimens were stained,and the positive staining of myocardial lesions was observed under microscopeand the results were analyzed.(2)The expression of JunB,MMP-2 and Leptin in myocardium was detected by IHC method.(3)Sensitivity of three histochemical and immunohistochemical methods in early ischemic myocardium were compared.Experimental results: 1.Histochemical staining(1)There were 20 cases of myocardial specimens in the experimental group.The positive results of HBFP staining in left ventricular wall,interventricular septum and apex were 9 cases(45%)respectively.The positive results of C-2R staining were 20 cases,100% respectively.The positive results of HBFP staining were 20 cases(100%),20 cases(100%)and 19 cases(95%)respectively.(2)There were 10 cases of sudden death caused by respiratory systemic diseases in the control group.The positive results of left ventricular wall,ventricular septum and apex of HBFP staining were 3 cases(30%),3 cases(30%)and 9 cases(10%)respectively.The positive results of 2R staining were 8 cases(80%),9 cases(90%)and8 cases(80%)respectively.The positive results of Heidenhain staining was 6 cases(60%),8 cases(80%)and 7 cases(70%).2.Immunohistochemistry technology(1)JunB,MMP-2 and Leptin showed no significant positive expression in the myocardium of cardiac death.(2)MMP-2 and Leptin were positive in gastric cancer positive control group while JunB was positive in rectal cancer positive control group.Conclusion: 1.The difference of histochemical HBFP and C-2R,Heidenhain staining rates and degree is large,The difference of C-2R and Heidenhain method positive staining ratio and degree is small,revealing that C-2R and Heidenhain method sensitivity is better;HBFP method,C-2R method and Heidenhain method compared,the sensitivity of positive staining of myocardial cells is poor.2.Immunohistochemical JunB,MMP-2 and Leptin tests were negative in human SCD myocardial tissues and could not be used as specific markers of SCD myocardial tissues which were fixed for a long time. |
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