Yan Liu

China University of Political Science and Law, Peping, Beijing, China

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Publications (18)19.72 Total impact

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    ABSTRACT: Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease affecting many organs and which is predominant in females. Although various manifestations of SLE may result in sudden death, pancarditis is very rarely encountered in forensic practice. We report on a case of sudden death caused by lupus-induced pancarditis. A 24-year-old male had pneumonia and intractable fever as initial signs when he was admitted to hospital. The patient had no symptoms associated with the cardiovascular system up to 3 days before he died. The echocardiogram and electrocardiogram were normal and diagnosis was not made until necropsy. This case is reported to broaden our understanding about the complexity of manifestations associated with SLE and inform clinicians and medical examiners of the potential for this type of lupus-induced pancarditis.
    Forensic science international 08/2013; · 2.10 Impact Factor
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    ABSTRACT: Although it is well known that 3,4-methylenedioxymethamphetamine (MDMA) can cause various cardiovascular abnormalities and even sudden death from cardiac arrhythmia, whether it has any effect on myocardial gap junctions, which might be one of the targets mediating MDMA-induced cardiotoxicity, remains unclear. OBJECTIVE: To test the hypothesis that MDMA may affect the myocardial gap junction protein connexin43 (Cx43) and induce cardiac dysrhythmia. METHOD: 1. in vivo study: adult rats were treated with a single dose MDMA administration (20mg/kg, i.p.). Electrocardiogram detection and immunohistochemical analysis were performed to evaluate cardiac function and expression of Cx43, respectively; 2. in vitro study: cultured ventricular myocytes of neonatal rats were treated with MDMA (10, 100, 1000μmol/L) for 1 hour. Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were performed to investigate the total Cx43 mRNA expression. Immunofluorescent analysis was used to evaluate the amount of junctional Cx43. The phosphorylation status of Cx43 at site Ser368 and intracellular Ca(2+) oscillation were also studied. RESULTS: obvious changes in electrocardiographic patterns were found in rats following MDMA administration. They were characterized by prolonged QRS duration associated with increased amplitude of QRS complex. The heart rates in treated rats were significantly decreased compared to the rats in the control group. The immunohistochemical findings revealed a significant decrease in Cx43 expression. The in vitro study also showed a marked decline in total Cx43 protein associated with reduction of Cx43 mRNA, whereas the phosphorylated Cx43 at Ser368 was increased. Decrease of junctional Cx43 was found correlated with reduction in N-cadherin induced by high concentration of MDMA. Additionally, confocal microscopy findings revealed alteration of intracellular calcium oscillation patterns characterized by high frequency and increasing influx Ca(2+). CONCLUSIONS: MDMA reduces expression of cardiac gap junction protein Cx43. The increase of phosphorylation status of Cx43 at Ser368 induced by MDMA is attributed, at least in part, to the Ca(2+)-dependent regulation of protein kinase C (PKC) activity. Our findings provide first evidence of MDMA-mediated changes in those cardiac gap junctions that may underlie MDMA-induced cardiac arrhythmia.
    Toxicology 06/2013; · 4.02 Impact Factor
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    ABSTRACT: Death following situations of intense emotional stress has been linked to the cardiac pathology described as stress cardiomyopathy, whose pathomechanism is still not clear. In this study, we sought to determine, via an animal model, whether the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α) and the amino peptide neuropeptide Y (NPY) play a role in the pathogenesis of this cardiac entity. Male Sprague-Dawley rats in the experimental group were subjected to immobilization in a plexy glass box for 1 h, which was followed by low voltage electric foot shock for about 1 h at 10 s intervals in a cage fitted with metallic rods. After 25 days the rats were sacrificed and sections of their hearts were processed. Hematoxylin-eosin staining of cardiac tissues revealed the characteristic cardiac lesions of stress cardiomyopathy such as contraction band necrosis, inflammatory cell infiltration and fibrosis. The semi-quantitative RT-PCR analysis for PGC-1α mRNA expression showed significant overexpression of PGC1-α in the stress-subjected rats (P<0.05). Fluorescence immunohistochemistry revealed a higher production of NPY in the stress-subjected rats as compared to the control rats (P=0.0027). Thus, we are led to conclude that following periods of intense stress, an increased expression of PGC1-α in the heart and an overflow of NPY may lead to stress cardiomyopathy and even death in susceptible victims. Moreover, these markers can be used to identify stress cardiomyopathy as the cause of sudden death in specific cases.
    Journal of Huazhong University of Science and Technology 12/2012; 32(6):823-8. · 0.58 Impact Factor
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    ABSTRACT: Commotio cordis is a rare and fatal mechano-electric arrhythmogenic syndrome, occurring mainly during sports activities. The present study describes two similar cases of sudden death caused by commotio cordis associated with homicide. The two decedents were both 15-year-old male teenagers. Both collapsed within several minutes after being punched in the precordial region, as observed by witnesses at the scenes. Although electrocardiograms were not recorded at the scenes or the hospitals, the sudden onset of cardiovascular, respiratory, and neural symptoms were consistent with sudden cardiac death caused by commotio cordis. Autopsy and forensic morphology both revealed no cardiac or pericardiac structural damage, evident lesions of other internal organs, or underlying diseases, along with negative toxicological analysis, conforming to criteria for diagnosis of commotio cordis. The diagnosis of commotio cordis by forensic pathologists is important in deliberating a verdict of homicide, especially involuntary homicide. In rare instances, a death caused by commotio cordis may have a homicide manner of death.
    Journal of Forensic Sciences 10/2012; · 1.24 Impact Factor
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    ABSTRACT: Commotio cordis is a rare and catastrophic mechano-electric feedback syndrome, and it is especially apt to occur in male children, adolescents and youths during sports activities. The authors present a case of unexpected sudden death due to commotio cordis associated with violence. In a house of detention, a 19-year-old boy was punched and kicked in the face, neck and chest during a fight with another suspect in their ward. Unfortunately, his precordium was the major injured region. The victim turned pale, then lost the ability to resist and lost consciousness immediately. When the emergency medical personnel arrived, the victim was found in a condition of cardiac and respiratory arrest and he was pronounced dead at the scene without cardiopulmonary resuscitation. Both autopsy signs and forensic morphology were in accord with the criteria for commotio cordis diagnosis, showing no cardiac or other organic fatal lesions and no underlying cardiac diseases; moreover, the toxicological screening was negative for alcohol, drug and common toxicants. In the present case, the whole fight was seen by some witnesses in their ward, and it was recorded by the monitoring unit. Based on the statements of the witnesses and the monitoring videotape, combined with the forensic pathological and toxicological examinations, all the testimonies supported the conclusion that the cause of death was commotio cordis.
    Medicine, science, and the law 04/2012; 52(2):119-21. · 0.48 Impact Factor
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    ABSTRACT: The aim of this study is to investigate the distribution of methamphetamine (MA) and its metabolite amphetamine (AP) in rat models of acute and subacute MA-ethanol combination abuse. Rats were fed with 20% ethanol for 4 weeks (chronic active-drinking group), and MA was injected intraperitoneally into chronically drinking and normal rats over 5 and 14 days, respectively. Then the rats from the acute and subacute combination abuse groups were euthanized, and ethanol, MA, and AP concentrations in samples were quantified. Except for the similar ethanol concentrations among acute and subacute groups, the MA and AP levels between groups were quite different. The concentrations of MA and AP in rats' liver, lung, kidney, and brain were much higher than other tissues, regardless of combination with ethanol. Also, MA and AP levels in subacute rats groups were higher than those in acute groups, and the levels of MA and the formation of AP in rats subjected to the combination abuse with ethanol were higher than in MA-only intoxicated rats. We conclude that ethanol has no bearing on the MA and AP distribution in body fluids and tissues, yet it can increase MA levels and markedly accelerate the formation of AP in combination-abuse rats. Comparing the acute and subacute combination-abuse rats' samples, it can be deduced that various accumulated amounts of MA and AP were unaffected by ethanol, even after multi-dose injection, regardless of acute or subacute use.
    Journal of analytical toxicology 01/2012; 36(1):30-5. · 2.11 Impact Factor
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    ABSTRACT: To provide references for forensic expertise by investigating the kinds of toxicant, routes of exposure and manners of poisoning deaths, etc. Six hundred and seven autopsy cases of poisoning deaths from 1957 to 2008 in Department of Forensic Medicine, Tongji Medical College (Tongji Forensic Science Identification Center of Hubei), were comparatively reviewed. In 218 cases from 1999 to 2008, more than 50% of decedents were male in the ages of 30-49. The toxicants are usually taken orally and the most common manner of death was accidental. The common substances involved in poisoning death were rodenticide, poisoning gas and insecticide. Compared to the data of 1983-1998 and 1957-1982, the common toxic agents had changed significantly. The number of cases involving insecticide and cyanide poisoning decreased in recent years, and the number of cases of rodenticide, poisoning gas, alcohols poisoning displayed an increase tendency, especially for drugs abuse. Poisoning deaths of pesticides remain a major public health problem for a long time and the awareness of prevention need to be raised, especially for the prevention of deaths from multiple poisons.
    Fa yi xue za zhi 06/2011; 27(3):200-4.
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    ABSTRACT: This paper presents seven fatal cases of aconite poisoning encountered in the Tongji Center for Medicolegal Expertise in Hubei (TCMEH), China, from 1999 to 2008 retrospectively. In six of the cases, deaths occurred after drinking homemade medicated liquor containing aconite, and in one case death was due to ingestion of traditional Chinese medication containing aconite. Forensic autopsy and pathological examinations ruled out the presence of physical trauma or life-threatening diseases. Diagnosis of aconite poisoning was made after postmortem toxicological analysis. Animal experiment was performed in one case demonstrating that the medicated liquor could cause death rapidly. We present the autopsy and histopathological findings, toxicological analysis, and results of animal experiment done on samples from those seven cases. As an important herbal Chinese medicine, Aconitum species deserve special attention, especially because it contains poisonous alkaloids.
    Forensic science international 06/2011; 212(1-3):e5-9. · 2.10 Impact Factor
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    ABSTRACT: Corneal opacity is one of the most commonly used parameters for estimating postmortem interval (PMI). This paper proposes a new method to study the relationship between changes of corneal opacity and PMI by processing and analyzing cornea images. Corneal regions were extracted from images of rabbits' eyes and described by color-based and texture-based features, which could represent the changes of cornea at different PMI. A KNN classifier was used to reveal the association of image features and PMI. The result of the classification showed that the new method was reliable and effective.
    Journal of Huazhong University of Science and Technology 04/2010; 30(2):235-9. · 0.58 Impact Factor
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    ABSTRACT: To study the relationship between changes of microbial ATP in four kinds of murine tissues and the postmortem interval (PMI), healthy SD rats were sacrificed and their muscles, livers, spleens and kidneys were sampled at different postmortem intervals. The concentration of microbial ATP was detected using bioluminescent assay and the data was statistically analyzed. The concentration of microbial ATP in muscle increased with PMI time. The peak appeared at the 7th day after death, and at the 10th day, microbial ATP in muscle tissue increased again. In internal organs, the peaks of microbial ATP were observed at the 8th day after death and the level decreased during 8-10 d. The differences in microbial ATP concentration in liver, spleen and kidney were not statistically significant. During day 0 to day 9 after death, the correlation was best between PMI and microbial ATP in muscle. With PMI as the independent variable, the cubic polynomial regression equation was Y=0.02X(3)-0.166X(2)-0.666X+13.412 (R (2)=0.989, P<0.01). In internal organs, the best correlation was found between PMI and microbial ATP during day 0 to day 10. With PMI as the independent variable, the cubic polynomial regression equation was Y=0.016X(3)-0.127X(2)-0.809X+13.324 (R (2)=0.986, P<0.01). There existed high correlations between PMI and microbial ATP concentration in rat tissues. Since only a small amount of tissue was needed for the detection and the sample was not affected by self-decomposition, the method may extend the time range of PMI estimation.
    Journal of Huazhong University of Science and Technology 12/2009; 29(6):679-83. · 0.58 Impact Factor
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    ABSTRACT: The records of 218 poisoning deaths from a Department of Forensic Medicine in a University of China, Tongji Center for Medicolegal Expertise in Hubei (TCMEH), from 1999 to 2008 were retrospectively reviewed. The majority (69.7%) of fatalities was between the ages of 20 and 49 years, and there was a male preponderance (male:female=1.7:1). The most common classes of substances involved in fatalities were rodenticide (19.7%), insecticide and herbicide (17.9%), carbon monoxide (16.5%), drugs (13.8%) and alcohols (12.4%). Ingestion was the predominant route of exposure (65.1%), followed in frequency by inhalation, injection and dermal. In vast majority (64.7%), the manner of death was accidental; suicidal intent was present in 25.2% of cases, homicide in 3.7%, and undetermined 6.4%. When compared to the former reports from the same institution, one for 1956-1984 and another for 1983-1999, an increase was found in the proportion of deaths due to rodenticides, CO, alcohols and drugs, as well as in accidental poisoning deaths. Poisoning deaths due to pesticides remain the major public health problem in China. Further regulatory enforcement should be carried out by government to restrict and manage the use of pesticides and rodenticides which are most toxic to humans.
    Forensic science international 10/2009; 193(1-3):88-94. · 2.10 Impact Factor
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    ABSTRACT: To study the relationship between the late postmortem interval (PMI) and trimethylamine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals (PMI) by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance (A value) and TMA-N at the concentration of 1-10 mg/L (R (2) = 0.9991). Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7 d since death, the best correlation between PMI and TMA-N concentration was found in muscles. With PMI as an independent variable, the cubic polynomial regression equation was y= -0.457x(3)+6.519x(2)-24.574x+27.207 (R (2)=0.969). During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x(3)-9.153x(2)+55.727x-95.819 (R (2)=0.953). It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.
    Journal of Huazhong University of Science and Technology 01/2009; 28(6):630-3. · 0.58 Impact Factor
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    ABSTRACT: In order to investigate the effects of aconitine on [Ca2+] oscillation patterns in cultured myocytes of neonatal rats, fluorescent Ca2+ indicator Fluo-4 NW and laser scanning confocal microscope (LSCM) were used to detect the real-time changes of [Ca2+] oscillation patterns in the cultured myocytes before and after aconitine (1.0 micromol/L) incubation or antiarrhythmic peptide (AAP) and aconitine co-incubation. The results showed under control conditions, [Ca2+] oscillations were irregular but relatively stable, occasionally accompanied by small calcium sparks. After incubation of the cultures with aconitine, high frequency [Ca2+] oscillations emerged in both nuclear and cytoplasmic regions, whereas typical calcium sparks disappeared and the average [Ca2+] in the cytoplasm of the cardiomyocyte did not change significantly. In AAP-treated cultures, intracellular [Ca2+] oscillation also changed, with periodic frequency, increased amplitudes and prolonged duration of calcium sparks. These patterns were not altered significantly by subsequent aconitine incubation. The basal value of [Ca2+] in nuclear region was higher than that in the cytoplasmic region. In the presence or absence of drugs, the [Ca2+] oscillated synchronously in both the nuclear and cytoplasmic regions of the same cardiomyocyte. It was concluded that although oscillating strenuously at high frequency, the average [Ca2+] in the cytoplasm of cardiomyocyte did not change significantly after aconitine incubation, compared to the controls. The observations indicate that aconitine induces the changes in [Ca2+] oscillation frequency other than the Ca2+ overload.
    Journal of Huazhong University of Science and Technology 11/2008; 28(5):499-503. · 0.58 Impact Factor
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    ABSTRACT: Aconitine, a highly poisonous type of alkaloid, has a widespread effect in stimulating the membranes of cardiomyocyte. However, other effects of aconitine on cardiomyocyte are unknown. In this study, we investigated whether aconitine also affects the phosphorylation status of connexin43 (Cx43) and intracellular [Ca(2+)] oscillation patterns in cultured ventricular myocytes of neonatal rats. As determined by Western blot analysis, a decreased percentage (47.68+/-2.29%) of phosphorylated Cx43 (P-Cx43) and a concomitant increased percentage (52.32+/-2.29%) of nonphosphorylated Cx43 (NP-Cx43) were found in aconitine-treated cultures, compared to the controls (82.77+/-2.04% for P-Cx43 and 17.23+/-2.04% for NP-Cx43). Quantitative immunofluorescent microscopy revealed similar changes in phosphorylation status occurring in Cx43 containing gap junctions in the cultures under the same treatment conditions. Real-time laser scanning microscopy indicated that intracellular [Ca(2+)] oscillations were relatively stable in control cultures, with occasional calcium sparks; after being treated with aconitine, high frequency [Ca(2+)] oscillations emerged, whereas typical calcium sparks disappeared. Furthermore, Western blot analysis revealed that, after aconitine treatment, the amount of phosphorylated PKCalpha decreased significantly. These observations suggest that aconitine not only induces dephosphorylation of Cx43 and PKCalpha, but also alters intracellular [Ca(2+)] oscillation patterns in cultured cardiomyocytes.
    Toxicology in Vitro 01/2008; 21(8):1476-85. · 2.65 Impact Factor
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    ABSTRACT: To study the damage of DNA in lymphocytes, brain cells and cardiac muscle cells of rats induced by different dose of tetramine and to speculate the toxicant mechanism of tetramine. The rat were poisoned by Tetramine, which was taken in by mouth. The rat poisoning models were used by 0.2, 0.1, 0.05, 0.01 mg x kg(-1) Tetramine, and comparison model was made by NS. Lymphocytes and brain cells and cardiac muscle cells of rats were separatd and collected form experimentation rat. DNA damages of cells which were exposed to different doses of tetramine were detected using the single cell gel electrophorresis (SCGE) or comet assay. DNA damages have been observed in lymphocytes, brain cells and cardiac muscle cells of rats which exposed form 0.01mg x kg(-1) doses of tetramine to 0.2mg x kg(-1) doses of tetramine. The test groups are very significantly statistical different to the control group (P<0.01). It is assumed that DNA damages of cells might be one of the toxicant mechanism of tetramine.
    Fa yi xue za zhi 03/2005; 21(1):27-9.
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    ABSTRACT: To study reasons that the quality of medico-legal autopsy in the medical tangle varies from different area. Collecting the cases of medical tangle in two medico-legal agencies, then counting percent of classes on the ten key-points, analyzing the data of the cases by chi-square test and t-test. It is indicated that the applied methods and standards of the two agencies are different. There are more different in seven keypoint of medicolegal autopsy by chi-square test. Six key-points are found to be more important to medico-legal appraiser, standardization of forensic autopsy, standardization of picking up specimen from the body, diagnosis standardization of the cause of death, consultation system and standardization of writing documents on medico-legal autopsy.
    Fa yi xue za zhi 02/2004; 20(4):215-7.
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    ABSTRACT: Tetramethylenedisulphotetramine(TETS) is virulent rodenticides which was strictly forbidden to use in China. Poison dose of TETS is very little, LD50 in rats in 0.1 mg/kg. Manifestations and signs of TETS poisoning are showed in 5 min. The long dated effect of poisoning is extremely strict. Mamy studys on TETS are restricted on the treatment of TETS poisoning, while that of poisoning mechanism is very few. This paper reviewed TETS poisoning mechanism, pathological changes and research advances.
    Fa yi xue za zhi 02/2004; 20(1):37-9.
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