Metabonomics Analysis of Brain Stem Tissue in Rats with Primary Brain Stem Injury Caused Death.

OBJECTIVES: To explore the potential biomarkers for the diagnosis of primary brain stem injury (PBSI) by using metabonomics method to observe the changes of metabolites in rats with PBSI caused death. METHODS: PBSI, non-brain stem brain injury and decapitation rat models were established, and metabolic maps of brain stem were obtained by LC-MS metabonomics method and annotated to the HMDB database. Partial least square-discriminant analysis (PLS-DA) and random forest methods were used to screen potential biomarkers associated with PBSI diagnosis. RESULTS: Eighty-six potential metabolic markers associated with PBSI were screened by PLS-DA. They were modeled and predicted by random forest algorithm with an accuracy rate of 83.3%. The 818 metabolic markers annotated to HMDB database were used for random forest modeling and prediction, and the accuracy rate was 88.9%. According to the importance in the identification of cause of death, the most important metabolic markers that were significantly up-regulated in PBSI group were HMDB0038126 (genipinic acid, GA), HMDB0013272 (N-lauroylglycine), HMDB0005199 [(R)-salsolinol] and HMDB0013645 (N,N-dimethylsphingosine). CONCLUSIONS: GA, N-lauroylglycine, (R)-salsolinol and N,N-dimethylsphingosine are expected to be important metabolite indicators in the diagnosis of PBSI caused death, thus providing clues for forensic medicine practice.

Pathological Changes and Cause of Death Associated with the Global Novel Coronavirus Disease (COVID-19).

The coronavirus disease 2019 (COVID-19) has been a global epidemic for more than three years, causing more than 6.9 million deaths. COVID-19 has the clinical characteristics of strong infectivity and long incubation period, and can cause multi-system damage, mainly lung damage, clinical symptoms of acute respiratory distress syndrome (ARDS) and systemic multiple organ damage. The SARS-CoV-2 virus is still constantly mutating. At present, there is no global consensus on the pathological changes of COVID-19 associated deaths and even no consensus on the criteria for determining the cause of death. The investigation of the basic pathological changes and progression of the disease is helpful to guide the clinical treatment and the development of therapeutic drugs. This paper reviews the autopsy reports and related literature published worldwide from February 2020 to June 2023, with a clear number of autopsy cases and corresponding pathological changes of vital organs as the inclusion criteria. A total of 1 111 autopsy cases from 65 papers in 18 countries are included. Pathological manifestations and causes of death are classified and statistically analyzed, common pathological changes of COVID-19 are summarized, and analytical conclusions are drawn, suggesting that COVID-19 infection can cause life-threatening pathological changes in vital organs. On the basis of different health levels of infected groups, the direct cause of death is mainly severe lung damage and secondary systemic multiple organ failure.

Might life-threatening acute pulmonary edema occur after using recombinant tissue plasminogen activator? A case report.

BACKGROUND: Recombinant tissue plasminogen activator (rt-pa) is the first-line drug for the treatment of acute ischemic stroke, and can lead to some complications.There were rare reports of death due to acute pulmonary edema during rt-pa thrombolysis treatment. CASE PRESENTATION: This study reports a 30-year-old man was diagnosed with acute ischemic stroke and underwent rt-pa thrombolytic therapy. Finally he died despite active rescue. CONCLUSIONS: The autopsy revealed that he died of acute pulmonary edema. This case suggests that it is necessary to pay close attention to the changes of vital signs during thrombolysis and be aware of possibility of pulmonary edema during thrombolysis.

Fatal poisoning by accidental ingestion of the "heartbreak grass" (Gelsemium elegans) verified by toxicological and medico-legal analyses.

We present a case of fatal poisoning from accidental ingestion of Gelsemium elegans (G. elegans), a rarely toxic plant. A 41-year-old man was found dead, at his home, 6 h after drinking homemade herbal liqueur during lunch. Autopsy and routine toxicological analyses identified neither significant pathological findings nor routine poisons. However, a local botanist revealed that the homemade herbal liqueur contained G. elegans, a poisonous plant specific to Asia. To ascertain whether the decedent had ingested G. elegans, we performed liquid chromatography-mass spectrometry (LC-MS) and found two alkaloids (gelsemine and koumine) in his blood, gastric contents, as well as the suspected herbal liqueur. The cause of death was therefore confirmed to be G. elegans poisoning. Case reports of fatal poisoning due to ingestion of G. elegans are quite rare in English. Therefore, the present case broadens the scope on the possibility of death due to ingestion of G. elegans for forensic pathologists and toxicologists.

Transcriptomic Changes of Astrocytes in the Brain of Rats with Subacute METH Exposure.

OBJECTIVES: To study the transcriptomic changes of astrocytes in the brain of rats exposed to methamphetamine (METH) and its possible mechanism in neurotoxicity. METHODS: The rats were intraperitoneally injected with METH (15 mg/kg) every 12 h for 8 times in total to establish the subacute rat model of METH. After the model was successfully established, the striatum was extracted, and astrocytes were separated by the magnetic bead method. Transcriptome sequencing was performed on selected astrocytes, and the differentially expressed genes were analyzed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. RESULTS: A total of 876 differentially expressed genes were obtained by transcriptome sequencing, including 321 up-regulated genes and 555 down-regulated genes. GO analysis revealed that differentially expressed genes were mainly concentrated in cell structure, biological process regulation, extracellular matrix and organelle functions. KEGG pathway enrichment analysis showed that steroids biosynthesis, fatty acid biosynthesis, peroxisome proliferators-activated receptor (PPAR), adenosine 5'-monophosphate-activated protein kinase (AMPK) and other signaling pathways were significantly changed. CONCLUSIONS: METH can cause structural changes of astrocytes through multiple targets, among which cellular structure, steroids biosynthesis and fatty acid biosynthesis may play an important role in nerve injury, providing a new idea for forensic identification of METH related death.

High-throughput 16S rDNA sequencing assisting in the detection of bacterial pathogen candidates: a fatal case of necrotizing fasciitis in a child.

Postmortem detection of pathogens in infectious deaths is quite important for diagnosing the cause of death and public health. However, it is difficult to detect possible bacterial pathogens in forensic practice using conventional methods like bacterial culture, especially in cases with putrefaction and antibiotic treatment. We report a fatal case caused by necrotizing fasciitis due to bacterial infection. An 8-year-old girl was found dead during sleep 4 days after a minor trauma to her left knee. The gross autopsy suggested that bacterial soft tissue infection might be the cause of death, and the microscopic examination confirmed the diagnosis. The slight putrefaction found at gross autopsy might interfere through postmortem bacterial translocation and reproduction with bacterial culture. High-throughput 16S rDNA sequencing was employed to identify possible pathogens. Bacterial DNA sequencing results suggested Streptococcus pyogenes and Staphylococcus, typical pathogens of necrotizing fasciitis in the tissue. 16S rDNA sequencing might thus be a useful tool for accurate detection of pathogens in forensic practice.

Rarely fatal bilateral re-expansion pulmonary edema after inserting a chest tube for unilateral spontaneous pneumothorax: a case report.

We describe a case of a 32-year-old man who died due to bilateral re-expansion pulmonary edema (RPE) following the insertion a chest tube for unilateral spontaneous pneumothorax. Fifteen minutes after inserting the chest tube, the patient with right spontaneous pneumothorax was diagnosed with right re-expansion edema by chest radiograph. Although multiple treatments were administered, the patient died. However, the findings from autopsy showed bilateral RPE existed in the decedent but not unilateral RPE. Autopsy, microscopic examination, and clinical records concluded that the cause of death was acute cardiac and respiratory failure due to bilateral re-expansion pulmonary edema following unilateral spontaneous pneumothorax. Bilateral RPE due to a unilateral pneumothorax is quite rare in clinical and forensic practice. To the best of our knowledge, this is the first time that the pathological changes of RPE have been described by gross and microscopic examinations. This case is reported to provide histopathologic references for diagnosis of RPE and indicate that combining death investigation, pathological findings and clinical courses plays a vital role in diagnosis of RPE in forensic pathology.

Role of CXCR1 and Interleukin-8 in Methamphetamine-Induced Neuronal Apoptosis.

Methamphetamine (METH), an extremely and widely abused illicit drug, can cause serious nervous system damage and social problems. Previous research has shown that METH use causes dopaminergic neuron apoptosis and astrocyte-related neuroinflammation. However, the relationship of astrocytes and neurons in METH-induced neurotoxicity remains unclear. We hypothesized that chemokine interleukin (IL) eight released by astrocytes and C-X-C motif chemokine receptor 1 (CXCR1) in neurons are involved in METH-induced neuronal apoptosis. We tested our hypothesis by examining the changes of CXCR1 in SH-SY5Y cells and in the brain of C57BL/6 mice exposed to METH by western blotting and immunolabeling. We also determined the effects of knocking down CXCR1 expression with small interfering ribonucleic acid (siRNA) on METH-exposed SH-SY5Y cells. Furthermore, we detected the expression levels of IL-8 and the nuclear factor-kappa B (NF-κB) pathway in U87MG cells and then co-cultured the two cell types to determine the role of CXCR1 and IL-8 in neuronal apoptosis. Our results indicated that METH exposure increased CXCR1 expression both in vitro and in vivo, with the effects obtained in vitro being dose-dependent. Silencing of CXCR1 expression with siRNAs reduced the expression of cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), and other related proteins. In addition, IL-8 expression and release were increased in METH-exposed U87MG cells, which is regulated by NF-κB pathway. Neuronal apoptosis was attenuated by siCXCR1 after METH treatment in the co-cultured cells, which can be reversed after exposure to recombinant IL-8. These results demonstrate that CXCR1 plays an important role in neuronal apoptosis induced by METH and may be a potential target for METH-induced neurotoxicity therapy. Highlights -Methamphetamine exposure upregulated the expression of CXCR1.-Methamphetamine exposure increased the expression of interleukin-8 through nuclear factor-kappa B pathway.-Activation of CXCR1 by interleukin-8 induces an increase in methamphetamine-related neuronal apoptosis.

Toll-Like Receptor 4 Mediates Methamphetamine-Induced Neuroinflammation through Caspase-11 Signaling Pathway in Astrocytes.

Methamphetamine (METH) is an amphetamine-typed stimulant drug that is increasingly being abused worldwide. Previous studies have shown that METH toxicity is systemic, especially targeting dopaminergic neurons in the central nervous system (CNS). However, the role of neuroinflammation in METH neurotoxicity remains unclear. We hypothesized that Toll-like receptor 4 (TLR4) and Caspase-11 are involved in METH-induced astrocyte-related neuroinflammation. We tested our hypothesis by examining the changes of TLR4 and Caspase-11 protein expression in primary cultured C57BL/6 mouse astrocytes and in the midbrain and striatum of mice exposed to METH with western blot and double immunofluorescence labeling. We also determined the effects of blocking Caspase-11 expression with wedelolactone (a specific inhibitor of Caspase-11) or siRNA on METH-induced neuroinflammation in astrocytes. Furthermore, we determined the effects of blocking TLR4 expression with TAK-242 (a specific inhibitor of TLR4) or siRNA on METH-induced neuroinflammation in astrocytes. METH exposure increased Caspase-11 and TLR4 expression both in vitro and in vivo, with the effects in vitro being dose-dependent. Inhibition of Caspase-11 expression with either wedelolactone or siRNAs reduced the expression of inflammasome NLRP3 and pro-inflammatory cytokines. In addition, blocking TLR4 expression inhibited METH-induced activation of NF-κB and Caspase-11 in vitro and in vivo, suggesting that TLR4-Caspase-11 pathway is involved in METH-induced neuroinflammation. These results indicate that Caspase-11 and TLR4 play an important role in METH-induced neuroinflammation and may be potential gene targets for therapeutics in METH-caused neurotoxicity.

Critical role of insulin­like growth factor binding protein­5 in methamphetamine­induced apoptosis in cardiomyocytes.

Methamphetamine (MA) is a highly abused amphetamine­like psychostimulant. At present, the mechanisms underlying MA­induced cardiotoxicity are poorly understood. The cardiotoxic effects have yet not been clearly elucidated with respect to the apoptotic pathway. Insulin­like growth factor binding protein­5 (IGFBP5) is important for cell growth control and the induction of apoptosis. The aim of the present study was to analyze whether IGFBP5 is involved in MA­induced apoptosis as a novel target. MA­induced apoptosis was observed in neonatal rat ventricular myocytes (NRVMs) in a concentration­dependent manner using a terminal deoxyribonucleotide transferase­mediated dUTP nick end­labeling assay. Using reverse transcription polymerase chain reaction and western blotting, MA was demonstrated to induce concentration­dependent increases in the expression of IGFBP5. Silencing IGFBP5 with small interfering RNA significantly reduced apoptosis and suppressed the expression of caspase­3 in NRVMs following treatment with MA. To the best of our knowledge, the present study provided the first evidence suggesting that IGFBP5 is a potential therapeutic target in MA­induced apoptosis in vitro, providing a foundation for future in vivo studies.

Remodeling of ion channel expression may contribute to electrophysiological consequences caused by methamphetamine in vitro and in vivo.

Methamphetamine (MA) is a psychostimulant. MA may induce numerous cardiotoxic effects, leading to cardiac arrhythmias, heart failure, eventually leading to sudden cardiac death. The deleterious effects of methamphetamine work in tandem to disrupt the coordinated electrical activity of the heart and have been associated with life-threatening cardiac arrhythmias. Remodeling of ion channels is an important mechanism of arrhythmia. Although arrhythmogenic remodeling involves alterations in ion channel expression, it is yet unknown whether MA induced electrical remodeling by affecting gene expression, and whether the changes in protein expression are paralleled by alterations in mRNA expression. Our study focused on the expression of ion channels which were correlated to the electrical remodeling caused by MA. We used RT-PCR and western blot to assess of the transcript and translate levels of ion channel subunits, including Ito: kv1.4, kv1.7, kv3.4, kv4.2; IK1: kir2.1, kir2.2, kir2.3, kir2.4; and ICa-l: Ca(2+)α1, Ca(2+)ß, respectively. The reversible effect of these changes after MA withdrawal was also evaluated. MA caused decrease in mRNA and protein levels in all ion channel subunits in vitro and also in vivo, is at this work. The kv3.4 and all 4 subunits of Kir2.0 family showed significant decrease than the other genes. Most of the channel subunit expression started to reverse after MA withdrawal for 4 weeks and significantly reverse in all of the channel subunits after MA withdrawal for 8 weeks. We found that CACNA1C and Kir2.0 family showed lower recoverability than the others after MA withdrawal for 8 weeks. The reduction of the ion channel expression levels may be the molecular mechanism that mediates the electrical remodeling caused by methamphetamine.

Quantitative analysis of GFAP- and S100 protein-immunopositive astrocytes to investigate the severity of traumatic brain injury.

Previous studies have shown that diffuse cortical astrocyte damage is seen in acute deaths due to brain injury and mechanical asphyxiation. The present study quantitatively investigated the number of astrocytes that showed GFAP- and S100-protein immunopositivity in the cerebral white matter and hippocampus at the sites distant from primary injury with regard to survival time, complication, and the immediate cause of death of brain injury cases. Autopsy cases of brain injury (8-48 h postmortem) comprising acute/subacute deaths (survival time, <3/6 h-3 days; n=27/42) and delayed deaths (survival time >3 days) with/without complications (n=30/22) were examined. Delayed death cases with complications were subdivided into those in which the immediate cause of death had been determined as cerebral dysfunction (n=22) and those that had been determined as due to fatal complications (n=8). For controls, natural deaths from pneumonias (n=12) and sudden cardiac deaths (n=27) were used. In brain injury cases, the numbers of astrocytes in the cerebral white matter and hippocampal CA4 region were significantly lower for subacute death and delayed death without complications (p<0.05-0.001). Delayed death with fatal complications showed a significant increase in the number of astrocytes (p<0.05). Among delayed death cases, the numbers of astrocytes were higher in the cases with fatal complications than in those without complications and with non-fatal complications, although the latter cases showed large variations in the numbers of these astrocytes. These findings suggest that critical brain injury causes acute death without evident astrocyte pathology and that subacute death is associated with progressive brain damage accompanied by an astrocyte loss. In delayed death cases, the numbers astrocytes might be closely related to the severity of posttraumatic brain injury. GFAP and S100-immunopositivity might be useful for elucidating the cause and process of deaths due to brain injury.

[Infantile DiGeorge syndrome: autopsy diagnosis and clinicopathologic analysis in 5 cases].

OBJECTIVE: To investigate clinicopathological features of DiGeorge syndrome (DGS). METHOD: The clinical features, histological and immunohistochemical findings were analyzed in 5 cases of DGS by autopsy. RESULTS: Five cases of DGS in male infants aged 4 days, 1 month, 7 months, 10 months, and 13 months respectively. Gross and microscopic observations revealed that thymic cortex was depleted of lymphocytes or showed few, dispersed lymphocytes. The thymic medulla showed predominantly epithelial cells with calcified Hassall bodies as well as lymphocyte depletion. T lymphocytes were also scarce in the tonsils, lymph nodes, spleen, and mucosa-associated lymphatic tissue of ileum. In addition, 3 of the 5 patients also showed parathyroid aplasia or dysplasia, and congenital hypertrophy of the ventricular septum. CONCLUSIONS: The pathological changes indicate that clinicians should be aware of defects of immune system if the infants suffer from severe infections. Pathologists should recognize the importance of abnormalities of lymphohematopoietic tissues in the diagnosis of primary immunodeficiency diseases such as DGS.

[The microglia activation characteristics of MA-induced neurotoxicity in the rats striatum].

OBJECTIVE: To investigate the activation characteristics of microglia (MG) in the rats striatum with MA-induced neurotoxicity. METHODS: Male Wistar rats were divided randomly into control group (n=24) and experimental group (n=24). The rats of experimental group were injected intraperitoneally with MA (15 mg/kg x 8 injections, at 12 hours interval). The rats of control group were administrated with saline. The tissues of striatum of two rat groups were harvested at 0.5 d, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d and 7 d post initial administrations of MA or saline. The structure changes were observed by transmission electron microscopy and CD-11b immunohistochemistry. The ratio of activated MG was calculated and statistically analyzed. RESULTS: In the control group, the morphological characteristics of the MG showed that the cell bodies were small with slender processes, high electronic density nucleus, and fewer organelles known as the "fork-type". In contrast, the MG in the MA-induced neurotoxicity group displayed larger cell body, shorter cell processes or disappeared, lower electronic density nucleus and rich organelles, resembling "bush-like" or "amoeba-like". The ratio of activated MG in control group was below 0.15 at all timepoints, whereas in the experimental group, the ratio of activated MG increased significantly from day 1 to day 7 (P<0.001). CONCLUSION: The continuous MA stimulation of the CNS results in prominent MG activation.

[Effect of methamphetamine on the microglial cells and activity of nitric oxide synthases in rat striatum].

OBJECTIVE: To study the changes in the microglial cells and the activity of nitric oxide synthase (NOS), inducible nitric oxide synthase (iNOS) and constitutive nitric oxide synthase (cNOS) in the striatum of rats with methamphetamine (METH) treatment. METHODS: The rats were randomly divided into two groups for injections with METH or saline. Specific antibody against OX-42 was used to detect the changes in the morphology and the number of microglia, and the activities of NOS, iNOS and cNOS were compared between the two groups. RESULTS: The microglial cells were activated and their number significantly increased in the striatum of rats with METH treatment as compared with those in the saline group. The activated microglial cells showed bushy and amoeboid morphologies in the METH group. METH also significantly enhanced the activities of NOS, iNOS and cNOS in the striatum (P < 0.05). CONCLUSION: Microglial activation and increased NOS activity may participate in METH-induced neurotoxicity in rat striatum.

[As2O3-induced permeability transition pore opening in mitochondria depends on Ca2+].

OBJECTIVE: To explore the mechanism of arsenite-induced permeability transition pore (PTP) opening and the role of Ca(2+). in As(2)O(3)-induced PTP opening. METHOD: The mitochondria were prepared from Wistar rat liver and mitochondrial swelling was assessed spectrophotometrically at 540 nm to evaluate PTP opening. The membrane potential of the mitochondria was measured with fluorescence spectrophotometry. RESULTS: PTP opening was induced with 10 micromol/L As(2)O(3) in the presence of 10 micromol/L Ca(2+), and the absorbance at 540 nm of the mitochondria did not decrease in response to exclusive treatment with 10 micromol/L As(2)O(3), or to 10 micromol/L As(2)O(3) plus 10 micromol/L Ca(2+) treatment with 0.5 mmol/L EGTA pretreatment. Treatment with As(2)O(3) at 0, 5, 10 and 20 micromol/L in the presence of 50, 20, 10 and 5 micromol/L Ca(2+), respectively, resulted in decreased absorbance at 540 nm of the mitochondria. CONCLUSION: Ca(2+) mediates As(2)O(3)-induced PTP opening. As(2)O(3) lowers Ca(2+) threshold necessary for eliciting PTP opening and thereby regulates cell apoptosis.

[Mechanism of opening of mitochondrial permeability transition pore induced by arsenic trioxide].

BACKGROUND & OBJECTIVE: Permeability transition pore (PTP) is central for apoptosis by acting as a good candidate pathway for the release of cytochrome c and apoptosis-induction factors from mitochondria. Arsenite may induce apoptosis via a direct effect on PTP. To characterize the exact mechanism for arsenite to induce PTP opening, the correlations of calcium-induced calcium release from mitochondria (mCICR) to As2O3-induced PTP opening and cytochrome c release from mitochondria were studied. METHODS: Mitochondria were prepared from Wistar rat livers. The effect of As2O3 on mitochondrial PTP opening was measured with ultraviolet (UV) spectrophotometer. The changes of Ca(2+) concentration were detected with UV spectrophotometer to monitor Ca(2+) -induced Ca(2+) release from mitochondria. Cytochrome c release mediated by Ca(2+) was measured with Western blot. RESULTS: As2O3 (10 micromol/L) combined with low concentration of Ca(2+) didn't induce PTP opening and cytochrome c release from mitochondria; while As2O3 (10 micromol/L) combined with high concentration of Ca(2+) induced PTP opening and cytochrome c release. When mCICR was inhibited, the effect of As2O3 and Ca(2+) on PTP opening and cytochrome c release was completely inhibited. CONCLUSION: As2O3-induced PTP opening and cytochrome c release depend on mCICR.

Degradation of human hair keratin scaffold implanted for repairing injured skeletal muscles.

OBJECTIVE: To observe the in vivo degradation process of human hair keratin (HHK) scaffold after implantation in rabbits. METHODS: Seven New Zealand rabbits were divided into 4 groups including a control group and 3 operation groups. HHK scaffold was implanted, after partial resection of the skeletal muscles, in rabbits of the 3 operation groups, followed by observation 1, 3, and 6 weeks later respectively. Routine morphological observation, histochemistry with ubiquitin and electron microscopy were performed. HHK scaffold incorporated 3 types of HHK with different degradation speeds, respectively designated types F, B, and Z. RESULTS: Light microscopic observation revealed that human hair cuticles began to strip off at the first postoperative week, and the material was homogeneous on the surface of which macrophagocytes and multinuclear giant cells adhered. At the third week HHK scaffold was degraded into particles as seen under electron microscope and was phagocytosed by macrophagocytes and multinuclear giant cells. Ubiquitin enzymatic histochemistry demonstrated that macrophagocytes, multinuclear giant cells were positive at the first week. At sixth week, further degradation of HHK scaffold occurred when newly generated muscles were seen beside the HHK. CONCLUSIONS: HHK scaffold is initially degraded extracellularly by ubiquitin system into particles, which are phagocytosed by the cells and degraded by the cooperation of lysosome and ubiquitin; meanwhile the satellite cells are activated, beginning to proliferate and eventually fused into newly generated muscle fibers.