Isolated rat cardiac myocytes as an experimental tool in the study of anoxic cell injury. Effect of reoxygenation — A preliminary report

Rat cardiac myocytes were isolated by heart perfusion in the presence of collagenase and incubated in the absence or presence of oxygen. As a result of anoxia, there was a gradual increase in plasma membrane permeability, noted as a decrease in trypan blue exclusion frequency, leakage of cytosolic lactate dehydrogenase and intracellular accumulation of the isotope compound ⁹⁹Tc^m-gluconate. The changes in plasma membrane permeability properties were preceded by a marked decrease in cellular ATP level and an increased proportion of contracted myocytes. The ability of the myocytes to resynthesize ATP and to recover from the anoxic injury upon reoxygenation decreased gradually with the length of initial anaerobic incubation during the first 25 min and disappeared after 30 min of anoxia, indicating that the anoxic injury to the isolated rat cardiac myocytes becomes irreversible after 25 – 30 min of anoxia. It is suggested that a decreased energy level is of primary importance for the initiation of cell injury in anoxia and that it is followed by cell contracture and subsequently by a disturbed plasma membrane function, cell swelling and death. This experimental model system of isolated viable rat cardiac myocytes is suitable for problems dealing with reversibility of myocytic injury.     

中介素（IMD）对大鼠心肌细胞缺氧-复氧损伤的作用

目的探讨中介素（IMD）对大鼠体外培养心肌细胞缺氧-复氧损伤的作用。方法用大鼠H9c2心肌细胞株制作实验模型,样本分为对照组、缺氧-复氧组（缺氧1h、复氧30min）、IMD组（缺氧-复氧前30min加入10-7mol/L IMD）。采用MTT比色法检测心肌细胞活力;透射电镜观察细胞超微结构;激光共聚焦显微镜观察并测定细胞内钙离子浓度;流式细胞术测定细胞凋亡率。结果与对照组比较,缺氧-复氧组和IMD组细胞存活率显著降低,而IMD处理组明显升高细胞存活率（P〈0.01）;在形态学上,IMD预处理可明显减轻缺氧-复氧对大鼠心肌细胞的损伤;缺氧-复氧组细胞[Ca2＋]i荧光强度和细胞凋亡率比对照组显著升高,IMD预处理可明显降低上述升高的比率（P〈0.01）。结论 IMD对大鼠心肌细胞缺氧-复氧损伤有一定保护作用,提高心肌细胞存活率、减轻心肌细胞钙超载和抑制凋亡是其作用途径。     

The application of ultraviolet irradiation to exogenous sources of DNA in plasticware and water for the amplification of low copy number DNA

Using high sensitivity forensic STR polymerase chain reaction (PCR) typing procedures, we have found low concentrations of DNA contamination in plasticware and water assumed to be sterile, which is not detected by standard DNA procedures. One technique commonly used to eliminate the presence of DNA is ultraviolet (UV) irradiation; we optimized such a protocol used in the treatment of water, tubes, plates, and tips for low copy number DNA (LCN) amplification. UV light from a Stratalinker((R)) 2400 was administered to 0.2, 1.5 mL tubes, and PCR plates contaminated with up to 500 pg of DNA. They were subsequently quantified with an ALU-based real-time PCR method using the Rotorgene 3000. Overall, there was a decrease in concentration of DNA recovered as the duration of treatment increased. Nonetheless, following 45 min of irradiating a PCR plate with 500 pg of DNA, nearly 6 pg were still detected. However, when the plate was raised within an inch of the UV source, less than 0.2 pg of DNA was detected. Additionally, lining the area around the samples with aluminum foil further reduced the amount of time necessary for irradiation, as only 30 min eliminated the presence DNA in the raised PCR plate. Similar experiments were conducted using tubes filled with a solution of DNA and water in equivalent concentrations for 50, 15, and 1.5 mL tubes with comparative results. It is plausible that the aluminum foil increased the amount of reflection in the area thereby enhancing penetration of UV rays through the walls of the plasticware. This protocol was tested for the possibility of inhibitors produced from irradiation of plastic tubes. As our protocols require less irradiation time than previous studies, PCR sensitivity was not affected. Moreover, the lifespan of the UV lamps was extended. Our findings demonstrate that this method is useful as an additional precautionary measure to prevent amplification of extraneous DNA from plasticware and water without compromising the sensitivity of LCN DNA amplifications.     

Detection of apoptosis in ischemic heart. Usefulness in the diagnosis of early myocardial injury

Myocardial samples of hearts with histologic findings of acute myocardial infarction (group A), sudden coronary deaths without histologic changes (group B), and chronic ischemic heart disease (group C) were analyzed to investigate the appearance of apoptosis in acute and chronic ischemic cardiac disorders. This analysis involved the morphologic detection of DNA strand breaks in myocyte nuclei by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and the biochemical determination of DNA laddering in the myocardium using archival formalin-fixed, paraffin-embedded tissue sections of human myocardium. The authors demonstrated that apoptosis of myocardial cells could occur after ischemic myocardial cell injury. In all documented cases of acute myocardial infarction (group A), the infarcted area included extensive presence of both apoptosis and necrosis. In the tissue bordering on and away from the obviously infarcted areas, positive nuclei were intermingled with nonstained normal myocytes. The number of positive nuclei decreased with the distance from the infarction foci. In group B, myocardial samples showed focal or diffuse nuclear positivity of varying degrees for apoptosis, confirming the presence of myocardial ischemic cell death, whereas the histologic diagnosis remained inconclusive. This finding suggests that apoptosis could be used as a marker for acute ischemic injury. In group C, stained nuclei were dispersed with intermingled normal cardiomyocytes.     

Direct effects of methamphetamine on hypertrophy and microtubules in cultured adult rat ventricular myocytes

Morphological alterations occasionally found in the myocardium of methamphetamine (MAP) abusers include hypertrophy, atrophy, disarrangement of myofibrils and fibrosis. These cardiac alterations have been thought to be due to an indirect action of MAP via catecholamines released by MAP administration. However, the direct effect of MAP on cardiomyocytes is not clear. In previous studies, we showed that cell size of isolated adult rat ventricular cardiomyocytes (ARCs) exposed to MAP was larger than that of untreated cells in culture supplemented with 10% fetal calf serum (FCS). In this study, to determine further the direct effect of MAP on cardiomyocytes, cultured ARCs were exposed to 0.05, 0.1 and 0.5 mM MAP for 7 days in culture medium without FCS following 6-day normal culture in medium containing FCS. Myocyte size was measured and microtubular (MT) structures which were associated with functional disorder of hearts were immunohistochemically observed using confocal microscopy. The size in treated ARCs significantly increased time- and dose-dependently as compared with untreated cells, but it decreased 7 days after exposure to 0.5 mM MAP. The increases in cell size, however, were lower than that in serum-supplemented cultures. MT structures in intact ARCs appeared as a filamentous network throughout the cytoplasm and around the nucleus. MAP exposure for 3 days promoted MT assembly, but in 7-day treated cells, MT and actin structures were injured. These results suggested that MAP directly induced cellular hypertrophy and might lead to cardiac functional disorder.     

The tendency of individuals to transfer DNA to handled items

This research investigates factors influencing the transfer of DNA to handled objects and the process known as 'shedding'. Volunteers were recruited to hold sterile plastic tubes using experiments originally designed by Lowe et al. [A. Lowe, C. Murray, J. Whitaker, G. Tully, P. Gill, The propensity of individuals to deposit DNA and secondary transfer of low level DNA from individuals to inert surfaces, Forensic Sci. Int. 129 (2002) 25-34]. Transferred cellular material was collected from the tubes and STR profiles generated using the AmpFlSTR SGM Plus multiplex with 28 and 34 PCR cycles. Volunteers were asked to hold the tubes with each hand, and to participate in a series of handwashing experiments. The DNA profiling results obtained from the transferred skin cells were compared. An attempt was made to characterize the volunteers as 'good' or 'bad' shedders and to establish which, if any, of the experimental variables were associated with 'good' shedding. Our results suggest that many factors significantly influence shedding, including which hand an individual touches an item with and the time that has elapsed since they last washed their hands. We have found that it may be more complicated than previously reported to categorise a person as being either a 'good' or a 'bad' shedder and that if truly 'good' shedders exist they may be significantly rarer than some have estimated. In the current research no 'good' shedders were observed in a group of 60 volunteers. Given these results, it seems that rather than being applied to individual forensic cases, knowledge of shedding characteristics will be most useful in providing general background data for the interpretation of trace DNA evidence.     

The effects of environment and substrata on deoxyribonucleic acid (DNA): the use of casework samples from New York City

This study was designed to analyze the effects of the environment and substrata on the quality of deoxyribonucleic acid (DNA) isolated from evidentiary specimens. The quality of DNA isolated from actual casework specimens was determined by measuring its size by agarose gel electrophoresis. The information obtained could be used to predict the suitability of the DNA in the samples for restriction fragment length polymorphism (RFLP) analysis. The evidentiary specimens chosen for DNA were classified according to substrate (scrapings, plastic bags, synthetics, denim, and carpet) and according to a subjective evaluation of the condition of the stain (soiled, damp, or putrefied) and to its size (small or large). The results show that DNA of sufficient quality and high molecular weight (HMW) can be reliably isolated from bloodstains deposited on evidentiary items which have an unknown environmental history and which have dried onto a variety of substrata. Subsequent RFLP analysis of a selected number of these samples verified that the DNA was suitable for this type of analysis.     

挤压伤大鼠早期心脏损伤的细胞机制

目的观察挤压伤大鼠血清对培养的新生大鼠心肌细胞的某些作用,拟阐明挤压伤早期心肌细胞损伤的细胞机制。方法培养1～3d龄SD大鼠心肌细胞,观察挤压伤大鼠血清对心肌细胞搏动频率、表面积、蛋白质含量、3H-亮氨酸掺入、胞内钙浓度和Fos蛋白表达的影响。结果与正常大鼠血清组比较,挤压伤大鼠血清培养的心肌细胞搏动频率(次/min)由88.3±20.6降为26.4±16.7,心肌细胞表面积、蛋白质含量、3H-Leu掺入、胞内游离钙浓度(nmol/L)和Fos蛋白表达阳性指数增加。结论挤压伤大鼠血清通过抑制细胞搏动,增加胞内钙浓度诱导Fos蛋白的表达,引起心肌细胞肥大,介导挤压伤早期的心脏损伤。     

Reducing and preventing organised crime: An evidence-based critique

Theory and practice in crime prevention and crime reduction have developed and changed significantly, but attention has been focused largely upon conventional forms of crime (especially street crime) and upon situational approaches to their reduction. Drawing on research with a variety of relevant organisations across Europe, this article explores the possibilities of developing more effective crime reduction strategies in respect of organized crime, an area in which (despite important exceptions, particularly in relation to financial regulation), law enforcement rather than prevention has continued to dominate the thinking and the practical responses of the police and other relevant agencies. It illustrates the difficulties of evaluating prevention in the many areas in which data quality on crime levels and their organisation are poor, but also gives examples (mainly financial crime) where private sector data quality are good enough to demonstrate effectiveness. It differentiates impact on crime from impact on the organisation of crime, and between market crimes involving voluntary vice and predatory crimes involving direct harm to victims, concluding that current performance indicators for enforcement agencies may need substantial revision if the focus shifts to organised crime reduction.     

HCN4 Gene Variations in Sudden Unexplained Nocturnal Death Syndrome in the Southern Han Chinese Population,

Sudden unexplained nocturnal death syndrome (SUNDS) is widely considered to be related to hereditary fatal arrhythmias. Hyperpolarization‐activated cyclic nucleotide‐gated channel 4 (HCN4) channels are widely distributed in sinus myocytes and play a profound role in generating pacemaker electro‐activity in cardiomyocytes. In the present study, the potential correlation between HCN4 gene variations and the occurrence of SUNDS was investigated. Genomic DNA was extracted from blood samples of both 119 unrelated SUNDS patients and 184 healthy individuals and screened for candidate HCN4 gene variants. One missense heterozygous variant c.1578C>T (Ala195Val) and four synonymous heterozygous variants c.1552C>T, c.2833C>T, c.3823C>T, and c.4189C>A were discovered in the SUNDS cases. The missense variant c.1578C>T (Ala195Val) was absent in 163 recruited controls and 105 persons of the Southern Han Chinese population, had in‐silico prediction indications as damaging, and was reported prevalent in sudden infant death, and is thus likely to be involved in SUNDS.     

急性心肌缺血再灌FOS免疫组织化学实验研究

探寻FOS蛋白在心肌早期缺血再灌流损伤中变化规律,为心性猝死的诊断提供新方法。利用SD大鼠建立心肌缺血再灌流损伤模型,设立正常、缺血对照组与缺血再灌组。心脏标本经HE染色及免疫级化观察。结果发现,在冷冻切片上缺血20min再灌流30min,再灌流区心肌细胞核呈阳性着色。但在石蜡切片上,缺血30min再灌流30min后,再灌流区才有心肌细胞核（37．76％±9．66％）呈弱阳性着色,再灌流60min后核呈棕褐色阳性染色,120min后开始减弱（35.36％±3.16％）。正常和单纯缺血组心肌细胞核未见有阳性反应。HE染色无明显病理改变。结果提示,SABC－FOS免疫组织化学方法最早可揭示心肌缺血20min再灌流30min的损伤,FOS蛋白在再灌流后60－120min之间可能有一个高峰表达。此法对显示实验性心肌早期缺血再灌流损伤有重要的价值。有望用于心性猝死的诊断。     

乌头碱对培养新生大鼠心室肌细胞Connexin43蛋白磷酸化的影响

目的建立细胞水平的染毒模型,观察乌头碱对心肌细胞缝隙连接蛋白Connexin43(Cx43)的影响。方法实验分0.25、0.5、0.75、1.0、1.5和2.0μmol/L等6个不同浓度乌头碱染毒组,运用蛋白印迹法和免疫荧光技术,检测各组及对照组心肌细胞Cx43蛋白磷酸化状态的改变。结果蛋白印迹检测显示,不同浓度染毒组心肌细胞中Cx43蛋白总量与正常对照组无显著差异;0.5μmol/L乌头碱染毒后,Cx43开始出现脱磷酸化;当染毒浓度达到1.0μmol/L后,Cx43脱磷酸化显著,且1.5及2.0μmol/L染毒效果和1.0μmol/L染毒组相当。免疫荧光分析结果提示乌头碱作用后,心肌细胞Cx43蛋白在羧基端第368位点丝氨酸残基(Ser368)发生明显的脱磷酸化。结论一定浓度的乌头碱能诱导心肌细胞缝隙连接蛋白Cx43发生显著脱磷酸化。     

早期心肌梗死心肌细胞内纤维连接蛋白的免疫组化观察

应用免疫组化LSAB法，对34例尸检心脏标本，进行心肌细胞内纤维连接蛋白用于早期心肌梗死死后诊断的研究。其中尸检及组织学证实心肌梗死5例，其心肌细胞内纤维连接蛋白均呈阳性。冠状动脉有硬化或冠状动脉口狭窄的可疑心肌梗死18例，其中15例心肌细胞内纤维连接蛋白阳性。非心性死亡对照组11例，心肌细胞内纤维连接蛋白均呈阴性。实验表明，心肌细胞内纤维连接蛋白免疫组化观察在急性心肌梗死，尤其是早期心肌梗死死后诊断上具有重要价值，为早期心肌梗死的死后诊断提供了一个实用方法。     

青壮年猝死综合征心肌细胞内Cx43的表达

目的观察连接蛋白43（Cx43）在青壮年猝死综合征（SMDS）者心肌细胞的表达,并探讨其法医学意义。方法筛选法医尸检案例45例,其中SMDS组、冠心病猝死组及对照组各15例。采用免疫组织化学和图像分析技术对不同组别Cx43蛋白在心肌细胞内的表达进行阳性单位（PU）定量检测,分析Cx43蛋白在各组表达的差异。所得数据进行统计学分析。结果 SMDS组心肌Cx43染色明显减弱,阳性着色条带分布不均、深浅不一,有的呈散在颗粒状;冠心病猝死组亦见类似变化;对照组未见明显变化。经统计分析发现,3组心肌细胞内Cx43表达的PU值存在显著性差异（P〈0.05）。结论 SMDS死前存在心肌缺血及心电紊乱,应属心性猝死范畴。     

Immunohistochemical study of fibronectin for postmortem diagnosis of early myocardial infarction

The postmortem diagnosis of early myocardial infarction has been a puzzling problem in forensic practice. In the present study, an immunohistochemical study of fibronectin (FN) was performed for the first time on 34 autopsy hearts to determine early myocardial infarction with streptavidin/biotin/peroxidase technique. Five cases of definite myocardial infarction showed positive FN staining of cardiomyocytes; of 18 cases where early myocardial infarction was suspected, positive FN staining of cardiomyocytes was found in 15 cases, but no such staining was seen in 11 non-cardiac death controls. The results led to the conclusion that positive FN staining in cardiomyocytes is a reliable marker of acute myocardial infarction and could be used as a new, sensitive method for the postmortem diagnosis of early myocardial infarction. It is worth noting that all cases in this study were autopsied between 8 h and 4 days after death and 5 cases had been fixed in 10% formalin for over 10 years. FN immunohistochemistry still gave satisfactory results in those cases. It seemed that FN was not affected by postmortem autolysis and formalin-fixation and could be used in routine forensic practice, especially for retrospective analysis of cases.     

Immunofluorescence demonstration of digoxin in human myocardial tissue and isolated rat cardiac myocytes with monoclonal antibodies

The aim of the present investigation was to identify the morphological correlates of digoxin binding sites in human heart muscle tissue and isolated viable rat heart myocytes. Cardiac glycoside linked to myocardial cells was demonstrated by monoclonal digoxin specific antibody and by FITC-conjugated anti-mouse immunoglobin serum. This versatile immunofluorescence method can be used in diagnostic and experimental studies of cardiac glycoside binding.     

冠心病心肌细胞凋亡的研究

探索细胞凋亡在心血管系统的意义,应用TUNEL法、透射电镜技术观察20例冠心病猝死者梗死区心肌细胞凋亡现象。冠心病组梗死区心肌细胞凋亡千分率(557.94±144.10％)明显高于正常对照组(34.30±20.68％),P<0.01,并有趋势表明,冠状动脉粥样硬化病变支数越多,梗死区心肌细胞凋亡越明显。电镜下见有的心肌细胞出现胞核体积缩小、染色质边聚、核膜完整的早期凋亡特征;有的则出现染色质更浓密、电子密度明显增加、结构模糊不清、核膜仍完整的中晚期凋亡细胞特征。细胞凋亡在冠心病心肌梗死是一种相当重要的现象。     

Fn免疫组化染色在人病毒性心肌炎死后诊断中的应用

目的研究纤维连接蛋白(Fn)免疫组化染色对轻度病毒性心肌炎的病理学诊断价值。方法运用兔抗人Fn多克隆抗体对人类心肌炎心肌标本进行Fn-LSAB免疫组化研究。结果发现心肌炎心肌组织内Fn大量沉积,部分心肌细胞内Fn阳性。结论Fn-LSAB染色可显示轻度病毒性心肌炎的心肌损害,Fn沉积是心肌组织存在炎症性病理变化的可靠标志之一。     

Evidence on unusual way of cocaine smuggling: cocaine-polymethyl methacrylate (PMMA) solid solution--study of clandestine laboratory samples

An abandoned clandestine laboratory was seized in Slovenia. All confiscated exhibits were analysed in a forensic laboratory, where the following analytical methods were applied: capillary gas chromatography coupled with mass spectrometry (GC-MS) combined also by solid-phase micro extraction (SPME) and pyrolysis (Py) technique, Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy with energy dispersive X-ray detector (SEM-EDX). The most interesting analytical findings can be summarised as follows: at the crime scene some plastic pieces, which contained cocaine dissolved (as solid solution) in polymethyl methacrylate-plexiglass (PMMA), were found. The highest cocaine concentration measured in the plastic sample was about 15% by weight. Two larger lumps of material (12 and 3 kg) were composed mainly of PMMA and CaCO3 and contained only 0.4 and 0.5% of cocaine, respectively. As for the low cocaine concentration, we assume that those two lumps of material represent discarded waste product--residue after the isolation of cocaine from plastic. Higher quantities of pure solvents (41 l) and solvent mixtures (87 l) were seized. We identified three types of pure solvents (acetone, gasoline and benzine) and two different types of solvent mixtures (benzine/acetone and gasoline/acetone). The total seized volume (87 l) of solvent mixtures holds approximately 395 g of solid residue formed mainly of PMMA and cocaine. Obviously solvent mixtures were used for isolation of cocaine from the plastic. Small quantities of relatively pure cocaine base were identified on different objects. There were two cotton sheets, most probably used for filtration. One sheet had traces of cocaine base (76% purity) on the surface, while cocaine in hydrochloride form (96%) was identified on the other sheet. GC-MS analyses of micro traces isolated from analytical balances showed the presence of cocaine and some common adulterants: phenacetine, lidocaine and procaine. A cocaine sample compressed in the shape of block was also seized. The above analytical findings inferred us to the conclusion that the illicit laboratory was used for the isolation of cocaine from PMMA resin. Further more, analyses confirm that not only isolation but also further manipulation of cocaine, i.e. adulteration/dilution, as well as the formation of cocaine blocks took place in the house. The information obtained through analyses also allowed us to make some hypotheses about possible multistage isolation procedure.     

Marks involving polyvinylchloride materials in motor vehicle collisions

In collisions where there is contact between a plasticized polyvinychloride surface and a vehicle, characteristic marks arising from the plastic are deposited on the vehicle. These appear as (a) a series of ridges and depressions with embedding plastic filaments, or (b) dispersed droplets along with brown mass. The corresponding features noticed on the plastic are (a) melting and marks of stretching, and (b) dark brown discolouration and cracked film structure. These marks are dependent on whether the deformation in the collision is either melting or thermal degradation. The occurrence of the marks from melting has been reported (J. Forensic Sci., 31 (1986) 778–781). In a recent case diffenent marks, namely, dispersed droplets along with brown mass caused by the thermally degrading plastic were observed. The appearance of either of these kinds of marks on the vehicle together with corresponding features on the plastic material constitute physical evidence of contact and can be used as proof of a collision.