Establishment of the Mathematical Model for PMI Estimation Using FTIR Spec-troscopy and Data Mining Method / 法医学杂志

Objective To analyse the relationship between Fourier transform infrared （FTIR） spectrum ofrat's spleen tissue and postmortem interval （PMI） for PMI estimation using FTIR spectroscopy combinedwith data mining method. Methods Rats were sacrificed by cervical dislocation, and the cadavers were placed at 20 ℃. The FTIR spectrum data of rats' spleen tissues were taken and measured at different time points. After pretreatment, the data was analysed by data mining method. Results The absorption peak intensity of rat's spleen tissue spectrum changed with the PMI, while the absorption peak position was unchanged. The results of principal component analysis （PCA） showed that the cumulative contribution rate of the first three principal components was 96%. There was an obvious clustering tendency for the spectrum sample at each time point. The methods of partial least squares discriminant analysis （PLS- DA） and support vector machine classification （SVMC） effectively divided the spectrum samples with different PMI into four categories （0-24 h, 48-72 h, 96-120 h and 144-168 h）. The determination coefficient （R2） of the PMI estimation model established by PLS regression analysis was 0.96, and the root mean square error of calibration （RMSEC） and root mean square error of cross validation （RMSECV） were 9.90 h and 11.39 h respectively. In prediction set, the R2 was 0.97, and the root mean square error of prediction （RMSEP） was 10.49 h. Conclusion The FTIR spectrum of the rat's spleen tissue can be effectively analyzed qualitatively and quantitatively by the combination of FTIR spectroscopy and data mining method, and the classification and PLS regression models can be established for PMI estimation.

Current Research and Prospects on Postmortem Interval Estimation / 法医学杂志

The researches on postmortem interval （PMI） estimation are very important and meaningful in forensic science. PMI estimation is also an important issue that must be solved in practice of forensic pathology. There are many defects existing in traditional methods for PMI estimation, so it is imperative to introduce new pathways. With the emergence of various new technologies, the researches on PMI estimation have a tendency from simple to complex with a growth of data. The present review firstly summarizes a series of methods used for PMI estimation, and then gives an outlook for the application of artificial intelligence algorithms in this field.

Effects of Temperature on FTIR Spectral Characteristics of Renal Tissue in Rats after Death / 法医学杂志

OBJECTIVES@#To analyse the Fourier transform infrared （FTIR） spectral data of renal tissue at different temperatures in rats after death, and to explore the effects of temperature on the FTIR spectral characteristics of renal tissue.@*METHODS@#The rats were sacrificed by cervical dislocation and placed at 4 ℃, 20 ℃ and 30 ℃. The FTIR spectral data of renal tissue were collected at different time points and analysed by data mining method.@*RESULTS@#The principal component analysis （PCA） results showed that there were significant trends of clustering in the samples of partial time point at 4 ℃, 20 ℃ and 30 ℃. Partial least square （PLS） regression models were established with the spectral data at three temperature groups. The performance of PLS regression models in 20 ℃ and 30 ℃ groups were more superior than that in 4 ℃ group, and the stability of the model in 20 ℃ group was better than that in 30 ℃ group.@*CONCLUSIONS@#There are differences in the FTIR spectral characteristics of renal tissue of rats after death at different temperatures. Temperature has a major impact on the performance of FTIR spectral PLS regression model. Therefore, in order to improve the accuracy of postmortem interval estimation, the effects of temperature on the model should be considered in the related study by spectral method.

Relationship between PMI and ATR-FTIR Spectral Changes in Swine Costal Cartilages and Ribs / 法医学杂志

OBJECTIVE@#To analyze postmortem chemical changes in Landrace costal cartilages and ribs using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, and to provide a novel technique for estimation of postmortem interval (PMI).@*METHODS@#The swines were sacrificed by hemorrhage and their costal cartilages and ribs were kept in 20 degrees C. The chemical analysis of the costal cartilages and ribs were performed using ATR-FTIR every 72 h. The correlation between the certain spectral parameters and PMI was also analyzed. The time-dependent changes of costal cartilages were more significant than ribs.@*RESULTS@#There were no obvious changes for the main absorbance bands position, and some absorbance band ratios showed time-dependent changes and significant correlations with the PMI.@*CONCLUSION@#ATR-FTIR has the ability to analyze postmortem chemical changes of the swine costal cartilages and ribs, and it can be a new method to estimate PMI based on spectroscopy.

Fourier Transform Infrared Microspectroscopy of Rat Kidney with Regard to Fa- tal Hyperthermia / 法医学杂志

OBJECTIVE@#To observe the chemical groups changing in rat kidney with regard to fatal hyperthermia by Fourier transform infrared microspectroscopy (FTIR-MSP) and to provide a new method to diagnose fatal hyperthermia.@*METHODS@#Rats were sacrificed by hyperthermia, brainstem injury, massive hemorrhage and asphyxiation and divided into groups. The renal samples were dissected immediately after death. The data of infrared spectroscopy in glomerulus were measured by FTIR-MSP.@*RESULTS@#The absorbances of 3290, 3070, 2850, 1540 and 1396 cm(-1) significantly increased (P < 0.05), and the ratios of Al650/A3290 and A1650/A1540 significantly decreased (P < 0.05) in group of hyperthermia.@*CONCLUSION@#FTIR-MSP can analyze the changes of chemical groups of kidney as an auxiliary diagnosis for discriminating hyperthermia with other causes of death.

The impact of gender, age and tissues in vitro on estimating postmortem interval by FTIR spectroscopy / 法医学杂志

To investigate the influence of such individual factors as gender, age and tissues in vitro to the postmortem interval (PMI) by the Fourier transform infrared (FTIR) spectrometer in animal experiments. SD rats were classified into male and female groups, different age groups (21-day, 42-day and 63-day group), and tissues in vitro and in vivo groups. The rats were sacrificed by cervical dislocation, whose bodies were kept in a controlled environmental chamber set at (20+/-2) degrees C and 50% humidity. The liver, kidney, spleen, myocardium, brain, lung and skeletal muscle tissues were collected for measurement from time zero to 48 h postmortem. With the change of PMI, no obvious changes were found in the main FTIR absorbance peaks and their ratios at different time points. All the experimental groups showed no significant changes when compared with the controls. The gender, age and tissues in vitro were not found to be contributing factors in the estimation of PMI via FTIR spectroscopy.

Changes of CK-MB and HSP 60 in electrical-injuried rats / 法医学杂志

OBJECTIVE@#To investigate the changes of creatine kinase-MB (CK-MB) and heat shock protein 60 (HSP 60) in rats without electric marks after electric injury, to identify the relationship of the CK-MB, HSP 60 and the time of electric injuries, and to evaluate the damage to cells after electric injury.@*METHODS@#The animal model of electric injury without electric marks was established by alternating current (voltage 110 V). Automatic biochemistry analyzer was used to detect the serum CK-MB and immunohistochemical staining technology was used to analyze the tissues of myocardium and left lobe of liver.@*RESULTS@#The amount of serum CK-MB was increased when the rats were injuried, and reached the peak at 30min. Then the amount of CK-MB began to decrease and showed a slight downward trend in 3-5 h after electric injury, and leveled off at 6 h. Immunohistochemistry staining also showed the changes of HSP 60 of rats' myocardial cells and hepatic cells regularly after electric injury.@*CONCLUSION@#The regular changes of serum CK-MB and tissular HSP 60 in rats can be used to diagnosis electric injury and assess the injury of internal organs after the electric injury without electric marks.

Pathological characteristics of sudden death caused by coronary thrombosis / 法医学杂志

OBJECTIVE@#To explore medico-legal characteristics of sudden death caused by coronary heart disease combined with coronary thrombosis.@*METHODS@#Ninety-six cases of sudden death caused by coronary heart disease were collected and divided into two groups: thrombus positive and thrombus negative groups. The time onset, induction and pathological features of coronary artery disease were analyzed.@*RESULTS@#Two groups showed man-dominant population. There were no statistical significant differences in season, circadian rhythm and induction factor. The thrombus positive group (age < 40) showed a higher disease incidence. Heart weight and degree of coronary stenosis were lower in thrombus positive group. However, there was no statistical difference in the number of atherosclerotic coronary arteries (> or = 2), the length of coronary lesions and myocardial infarct. But thrombosis positive group showed lower tendency.@*CONCLUSION@#Two groups are man-dominant population and similar induction factor, lesion position, mechanism of death. But thrombus positive group appeared more in a younger population and the degree of coronary stenosis is milder than thrombus negative group. Forensic pathologists should pay more attention to these characteristics in death investigation.

Review on estimation of postmortem interval using FTIR spectroscopy / 法医学杂志

Estimation of the postmortem interval (PMI) is a practical task in daily forensic casework. Researches on PMI is an important practical project in forensic field. Estimation of the time since death is influenced by internal and external, antemortem and postmortem factors, thus the old methods have limitations. Fourier transform infrared (FTIR) spectroscopy has been applied to study the pure protein, nucleic acid and carbohydrate and to detect the changes in complex cells and tissues. At present because the powerful software has could be used to achieve the spectrum transformation, smoothing, baseline correction and normalization, it is possible to analyze the samples quantitatively with the FTIR which has been applied in the biology and clinical medicine. This paper has reviewed the mechanism of FTIR and its application in biomedicine. The postmortem FTIR spectral changes were also discussed, which showed its potential for estimating PMI.

Estimation of postmortem interval using FTIR spectroscopy in rats' cardiac muscle / 法医学杂志

OBJECTIVE@#FTIR (Fourier transform infrared) spectroscopy was applied to observe the process of postmortem degradation in rats' cardiac muscle and provided a new method for the estimation of post-mortem interval (PMI).@*METHODS@#The rats were sacrificed by cervical dislocation and the bodies were kept in a controlled environmental chamber set at (20 +/- 2) degrees C. The FTIR spectra was applied to measure the changes of different chemical group from rats' left ventricle muscle at the different time point postmortem.@*RESULTS@#There were not obvious changes for the main FTIR absorbance peaks. But the different FTIR absorbance at the wave-number (cm(-1)) indicated the three types: increase, decrease, stable. The various absorbance ratios also demonstrated the similar changes.@*CONCLUSION@#FTIR spectroscopy may be potentially used as an effective method for estimating PMI in forensic practice using cardiac muscle tissue.

Analysis of 574 cases of high-fall death / 法医学杂志

OBJECTIVE@#To establish a database of high-fall death cases for future forensic study and practice, based on the scene investigation, injury characteristics and other informations.@*METHODS@#Five hundred and four cases of high-fall death from 5 provinces and cities were included in the study. Data including personal information of the deceased, scene investigation, autopsy findings, history of mental illness and the results of toxicology were collected and analyzed.@*RESULTS@#The male accidental death rate was significantly higher than that of female. No case of suicide was found in the 0-10 age group, while the suicide rate was apparently higher in the 60 years or over age group than that of accident. Most of the accident cases occurred at workplace, with head landing first and foot or lower-extremity landing first observed from height below 10 m and between 10-25 m, respectively.@*CONCLUSION@#The majority of cases have obvious conclusions. A substantial set of the cases, however, is still difficult to determine the mechanism of injury and the manner of death. So further study should be performed.

The changes of Fourier transform infrared spectroscopy in rat's brain / 法医学杂志

OBJECTIVE@#To apply Fourier transform infrared (FTIR) spectroscopy to study the process of postmortem degradation of the rat brain and to provide a new way for the estimation of postmortem interval (PMI).@*METHODS@#The rats were sacrificed by cervical dislocation and the bodies were kept in a controlled environmental chamber set at (30 +/- 2) degrees C. To measure the content of the chemical groups in postmortem rat brains at the different time points from 0 to 36 h using the FTIR spectrograph.@*RESULTS@#With prolongation of PMI, the peak position of main absorbance bands in the FTIR spectra showed no significant changes, while the peak levels showed dramatic changes: (1) The relative peak intensity of 1080 cm(-1), 1238 cm(-1) (I1080/I1398, I1238/I1398) associated with nucleic acid decreased obviously; (2) The peak intensity ratio at Amide I, II (I1647/I1541) decreased; (3) The peak intensities at 1456 cm(-1) and 1398 cm(-1) showed a decreased and an increased trend, respectively; (4) Compared to the peak intensity of 1647 cm(-1), the peak intensities at 2852 cm(-1), 2871 cm(-1), 2923 cm(-1), and 2958 cm(-1) tended to increase, with only a slightly increased tendency in peak intensity of 2871 cm(-1).@*CONCLUSION@#FTIR spectroscopy may be potentially used as an effective method for estimating the PMI in medicolegal practice using brain tissue sample.

Expression of brain natriuretic peptide and c-fos gene in rat after acute myocardial ischemia and its medicolegal significance / 法医学杂志

OBJECTIVE@#To study the mRNA expression of BNP and c-fos gene in rat heart after acute myocardial ischemia (AMI) and to provide a marker for its medicolegal diagnosis.@*METHODS@#AMI animal model of rat was made by ligating LAD. mRNA expression of BNP and c-fos gene were studied with RT-qPCR and ordinary PCR at 10 min, 30 min, 60 min and 3h after the successful ligation. The H&E staining was also used. Changes of the mRNA expression in different time groups were compared.@*RESULTS@#There was significant difference in BNP mRNA expression of the 3 h group by RT-qPCR compared with normal control group, 10 min, 30 min, and 60 min groups (P < 0.05). There were dramatic differences in c-fos mRNA expression between every two groups (P < 0.05) except between the normal group and the 10 min group, between the 30 min group and the 3 h group. The peak of c-fos expression was in 60 min group. No difference was shown between groups by the ordinary PCR. Myocardial fiber acidophilia staining and wavy changes could be seen occasionally at 3 h experimental group by H&E staining.@*CONCLUSIONS@#C-fos gene probably be used as an auxiliary test for myocardial ischemia of duration of 30 minutes or longer. RT-qPCR may be suitable for diagnosis of early AMI.

The retrospective study of sudden cardiac death in 118 cases / 法医学杂志

The sudden cardiac death (SCD) is the primary cause of death in adults. 118 cases of sudden cardiac death from 1998 to 2005 in Shanxi area were studied. The results showed that there as 5.9 times of males as females. There were 55.1% coronary artery diseases, 17.8% myocarditis, 9.3% cardiomyopathy, 2.5% each of congenital heart diseases, valvular heart diseases, and rupture of dissecting aneurysm of aorta, and 4.55 of other diseases. The data indicate that SCD happened in males more often than in females and coronary artery disease was the most common disease. Myocardititis was more common in adolescents and cardiomyopathy was more prevalent in young adults resulting in SCD. The cardiac disease without abnormal structure changes might also be a serious threat to human health.

Corpus of biochemical changes after death by potassium intoxication in rabbits / 法医学杂志

OBJECTIVE@#To explore the objective evidence of the corpus biochemical changes in rabbits for postmortem diagnosis of potassium intoxication.@*METHODS@#Rabbits were sacrificed by Infusion of 0.3% KCl at full speed push or 1% KCl at 100 drip/min, respectively, with normal rabbits used as control. Cardiac blood and urine samples were collected before and after potassium infusion to examine the concentrations of various electrolytes (K+, Na+, Ca2+, Mg2+, Cl-, and HCO3-) and to observe the antemortem and postmortem biochemical changes.@*RESULTS@#The mean lethal infusion time in the 0.3%KCl group was longer than that in the 1% KCl group (P = 0.006). The serum concentration of K+ increased while the serum concentrations of Na+, Ca2+, Cl-, and HCO3- decreased after the infusion. There were no statistically significant differences in the whole blood concentration of K+ as well as the serum concentration of Mg2+ between the two groups (P = 0.062). There were statistically significant differences in the concentrations of whole blood K+, as well as serum Na+, Mg2+, and Cl-, but not in the serum K+, Ca2+, and HCO3-. There were no statistically significant differences seen in the urine volumes and the concentrations of all the urine electrolytes between the groups.@*CONCLUSION@#Examination of the concentrations of K+ both in the whole blood and serum, as well as Mg2+ in the serum may be helpful for postmortem diagnosis of potassium intoxication.

Morphological changes in rabbits died of potassium intoxication / 法医学杂志

OBJECTIVE@#Morphologic features of the corpse of rabbits died of potassium intoxication were studied in order to elucidate an objective evidence for forensic determination of death caused by potassium intoxication.@*METHODS@#Macroscopic, microscopic, and ultrastructural (by transmission electron microscopy) changes were observed in the heart, brain, and kidney of rabbits killed by intravenous push or continuous infusion at 100 drips per minute with 0.3% and 1% KCl, respectively. Normal rabbits without any treatment killed by bleeding were used as controls.@*RESULTS@#Macroscopically, cardiac dilatation and congestion/stasis as well as ischemic and hypoxic changes in various organs were observed in rabbits died of potassium injection. Microscopically and ultrastructurally, there were destruction of the cardiac fibers with thickening, concentrating, or disappearing of the Z-line, constriction of the glomerular capillaries, enlargement of the Bowman capsule, thinning and fusion of foot processes, as well as apoptosis with phagocytosis in brain observed, particularly in the group infused with 1% KCl.@*CONCLUSION@#The morphologic changes observed in the heart and kidney appear to be characteristic, supporting death caused by potassium intoxication.

Expression of synaptophysin in experimental diffuse brain injury / 法医学杂志

OBJECT@#To investigate the changes in the expression_level of synaptophysin following diffuse brain injury (DBI) in rats and to correlate the changes of the synaptophysin expression_level with the post injury time interval.@*METHODS@#Wister rats were used as a DBI model induced by Marmarou method. The changes of synaptophysin immunoreactivity on coronal sections of the rats sampled at different post-injury time intervals were used as a marker. The densitometry of the synaptophysin immunoreactivity was documented by imaging technique and analyzed by SPSS software.@*RESULTS@#The expression level of synaptophysin in DBI rats showed dynamic changes following DBI as well as during the repairing period.@*CONCLUSION@#The changes of synaptophysin level may be used as a marker for estimation of the post injury time interval in DBI.

Percutaneous radiofrequency ablation therapy with left single lung ventilation for liver carcinoma in the hepatic dome / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the advantages of percutaneous radiofrequency ablation (PRFA) therapy with contralateral single lung ventilation (SLV) for liver carcinoma in the hepatic dome (LCHD).</p><p><b>METHODS</b>The clinical data of 10 patients (the SLV group) with LCHD consecutively treated from January to December 2006 were retrospectively analyzed. And another 10 cases (the control group) with LCHD treated from January 2004 to December 2005 were selected with a strict inclusion criterion for compared test according to rules of same diagnosis, similar tumor bulk and site, same sex, similar age and liver function. The patients' ages and tumor diameters of the 2 groups were compared with t-test and the rates of complications and incomplete tumor ablation were compared with chi2-test.</p><p><b>RESULTS</b>There was no statistical difference in ages and tumor diameters between the 2 groups (P > 0.05). The average number of radiofrequency ablation needle punctures in the SLV group was significantly less than the control group (3.4 +/- 0.4 vs. 6.1 +/- 0.8, P < 0.01). There was no bronchial intubation related complications like hypoxemia, atelectasis, lung infection and no puncture related complications like pneumothorax, hemothorax, hemoperitoneum and bile leakage in the SLV group. Two cases in the control group had complications including pneumothorax (n = 1) and pleural effusion (n = 1). There was no mortality in the 2 groups. Though the rate of incomplete tumor necrosis in the SLV group was not statistically lower than that in the control group (10% vs. 40%), the occurrence rate of the undesirable event (complication and incomplete tumor necrosis) of the SLV group was significantly lower than that of the control group (10% vs. 60%, P < 0.05). The durations and costs of operating procedure were not significantly different between the 2 groups.</p><p><b>CONCLUSION</b>Left SLV makes PRFA for LCHD more efficient, effective and safe.</p>

Determination of residual epoxyethane in medical instruments by headspace capillary gas chromatography / 中国医疗器械杂志

<p><b>OBJECTIVE</b>To establish a method of determining the residual epoxyethane in medical instruments.</p><p><b>METHOD</b>An HP-5 capillary column (30 m x 0.32 mm x 0.25 microm), an FID detecter and an oven were used in the determination. The oven temperature was kept at 120 degrees C for 8 minutes, the example inlet temperature was kept at 200 degrees C, while the detecter temperature was kept at 250 degrees C.</p><p><b>RESULT</b>The method has a linear range between 5.1920-51.920 microg, (r = 0.997, n = 6). The average rate of recovery of the injecter is 103.3%. The average rate of recovery of the infusion devices is 81.04%.</p><p><b>CONCLUSION</b>The method has been proved to be convenient, sensitive and accurate. It is suitable for the determination of residual organic solvents in medical instruments.</p>

Analysis of relationship between injury and disease by cardiac functional indicators in hypertension rat after trauma / 法医学杂志

OBJECTIVE@#To observe the changes of cardiac functional indicators in spontaneously hypertension rats (SHR) suffered by struck injuries of soft tissues, form which to discuss the significance in relationship between injury and disease.@*METHODS@#SHRs were divided into four groups according to the degree, and whose thigh was struck with the homemade hit instrument. Then the blood pressure, heart rate as well as serum biochemical indicators (CK, CK-Mb, LDH, Cr, BUN, HBDH and AST) were examined. In addition, the morphological changes of heart, brain and kidney were also observed.@*RESULTS@#The observe values of heart rate and blood pressure of SHRs seemed have relation to the degree of damage, but there were no statistically significance between different hit degree groups. In terms of serum biochemical indicators, all seven indicators of the hit group had significant difference with that of the control group, and the AST CK, CK-MB levels were difference between the group of different strike degree.@*CONCLUSIONS@#Struck injuries of soft tissues can result in forepart damage of cardiac muscle. The biochemical indicators reflect the degree of injury, and they could be used as a type of objective enzymology indicators for analysis of the relationship between injury and disease in forensic practice.