Dehydrogenase conversion to oxidase and lipid peroxidation in brain after carbon monoxide poisoning.

The conversion of xanthine dehydrogenase to xanthine oxidase and lipid peroxidation were measured in brain from carbon monoxide- (CO) poisoned rats. Sulfhydryl-irreversible xanthine oxidase increased from a control level of 15% to a peak of 36% over the 90 min after CO poisoning, while the conjugated diene level doubled. Reversible xanthine oxidase was 3-6% of the total enzyme activity over this span of time but increased to 31% between 90 and 120 min after poisoning. Overall, reversible and irreversible xanthine oxidase represented 66% of total enzyme activity at 120 min after poisoning. Rats depleted of this enzyme by a tungsten diet and those treated with allopurinol before CO poisoning to inhibit enzyme activity exhibited no lipid peroxidation. Treatment immediately after poisoning with superoxide dismutase or deferoxamine inhibited lipid peroxidation but had no effect on irreversible oxidase formation. Biochemical changes only occurred after removal from CO, and changes could be delayed for hours by continuous exposure to 1,000 ppm CO. These results are consistent with the view that CO-mediated brain injury is a type of postischemic reperfusion phenomenon and indicate that xanthine oxidase-derived reactive oxygen species are responsible for lipid peroxidation.     

高压氧对急性CO 中毒大鼠脑内源性神经干细胞的影响

目的:探讨高压氧对急性CO中毒大鼠脑内源性神经干细胞的影响,分析HBO治疗急性CO中毒脑损伤的机制。方法:建立急性CO中毒大鼠模型,给予高压氧(HBO)治疗后,H-E染色观察大鼠脑组织病理学变化,免疫组织化学方法检测大鼠脑内神经干细胞(nestin)和星形胶质细胞(GFAP)的表达。结果:H-E染色标本上,对照组脑内神经元形态正常,染毒组脑皮质出现大量变性坏死细胞,海马锥体细胞层稀疏,HBO组坏死细胞明显减少。免疫组化结果显示对照组nestin和GFAP表达数量形态均正常,染毒组nestin表达增加,但无统计学意义,GFAP形态数量发生改变,HBO组nestin表达明显增加,且在大脑皮层可见部分nestin阳性细胞和nestin-GFAP双阳性细胞;GFAP表达趋于正常。结论:急性CO中毒作为脑损伤因素可轻度激活大鼠脑内源性神经干细胞,并使星形胶质细胞增生变形、神经元变性坏死,HBO治疗可减轻星形胶质细胞损伤,明显激活内源性神经干细胞,并促使其增殖、迁移和分化。提示HBO可能通过激活神经干细胞起治疗作用。     

The role of reactive oxygen species and oxidative stress in carbon monoxide toxicity: An in-depth analysis

Abstract

The underlying mechanism of the central nervous system (CNS) injury after acute carbon monoxide (CO) poisoning is interlaced with multiple factors including apoptosis, abnormal inflammatory responses, hypoxia, and ischemia/reperfusion-like problems. One of the current hypotheses with regard to the molecular mechanism of CO poisoning is the oxidative injury induced by reactive oxygen species, free radicals, and neuronal nitric oxide. Up to now, the relevant mechanism of this injury remains poorly understood. The weakening of antioxidant systems and the increase of lipid peroxidation in the CNS have been implicated, however. Accordingly, in this review, we will highlight the relationship between oxidative stress and CO poisoning from the perspective of forensic toxicology and molecular toxicology.     

Potential Use of Hyperoxygenated Solution as a Treatment Strategy for Carbon Monoxide Poisoning

Aim

Carbon monoxide (CO) poisoning can cause permanent damage in tissues that are sensitive to hypoxia. We explored the feasibility and efficacy of using a hyperoxygenated solution (HOS) to treat severe acute CO poisoning in an animal model.

Methods

Male Sprague-Dawley rats were subjected to CO poisoning. The HOS was administered into the femoral vein of these rats through a catheter (10 ml/kg). Carboxyhemoglobin (COHb) and blood gases were used to assess the early damage caused by CO poisoning. S100β was measured to predict the development of late cognitive sequelae of CO. The Morris water maze test was performed to assess cognitive function, and Nissl staining was performed to observe histologic change.

Results

The COHb concentrations rapidly decreased at 5 min after the HOS administration; however, the PaO₂ and SaO₂ in rats treated with HOS increased significantly 5 min after the HOS administration. The S100β concentrations, which increased significantly after CO poisoning, increased at a much slower rate in the rats treated with HOS (HOS group) compared with the rats treated with O₂ inhalation (O₂ group). The escape latency in the place navigation test was shortened after CO poisoning on days 11-15 and days 26-30, and the swimming time in quadrant 4 in the spatial probe test on days 15 and 30 after CO poisoning was prolonged in the rats treated with HOS injection compared with the rats treated with oxygen inhalation or normal saline injection. The neuronal degeneration in the HOS group was alleviated than that in the CO or O₂ group.

Conclusion

HOS efficiently alleviates the brain damage in acute CO-poisoned rats and thus may serve as a new way to treat human patients with CO poisoning in clinical practice.     

Regional cerebral blood flow of the rat in acute carbon monoxide intoxication.

The effect of carbon monoxide (CO) on the regional cerebral blood flow was studied by exposing lightly anesthetized rats for 30 min to 0.5, 1.0, 1.5, and 2.0% CO gas mixtures. Cortical cerebral blood flow (CBF) increases of near 200%, 300%, and 400% control were observed at 0.5, 1.0, and 1.5% CO, respectively; whereas at 2.0% CO a reversal of the CBF increase was observed with values declining to near 300% control. The CBF response of subcortical, cerebellar, and brain stem areas was quantitatively similar to that of cortex, indicating that the CBF changes in CO intoxication are general. The decrease in CBF at 2.0% CO was related to significant decreases in arterial CO2 tension. Comparison of the CBF data to previous metabolic results in CO poisoning suggests that the CBF increases are a principal factor in the maintenance of an intact energy state in CO poisoning.     

HBO治疗对急性CO中毒后海马不同分区神经细胞凋亡的作用研究

目的:通过研究高压氧(HBO)治疗急性CO中毒大鼠海马不同分区神经细胞凋亡情况,探讨HBO治疗急性CO中毒的应用及机理。方法:利用雄性SD大鼠,建立急性CO中毒模型。应用免疫组织化学以及免疫荧光的方法,测定在染毒和CO中毒HBO治疗后1 d、3 d、7 d、14 d和21d Bcl-2、caspase-3、Neu N、BAX和MMP-9的表达水平的变化。结果:海马CA3区神经细胞对急性CO中毒与HBO治疗比CA1和CA2区更加敏感;急性CO中毒后,海马各区神经细胞凋亡程度随1 d、3 d、7 d、14 d和21 d时间延长而加重;BAX、caspase-3和Bcl-2等凋亡相关因子的表达水平与MMP-9的变化趋势一致:在1d开始增多,3d达到最大值,7d开始减少,14 d与21 d与正常组类似;CO中毒大鼠进行HBO治疗后,海马各区MMP-9、BAX、caspase-3和Bcl-2的表达水平明显降低;且HBO治疗7 d后,海马各区这些凋亡相关因子的表达降低最为明显。结论:海马CA3区神经细胞对急性CO中毒及HBO治疗敏感;海马神经细胞凋亡可能与神经细胞表达MMP-9降解神经细胞周围的基质,表达BAX、caspase-3和Bcl-2等凋亡相关因子促进凋亡发生有关;HBO治疗可降低MMP-9以及BAX、caspase-3和Bcl-2等凋亡因子的表达,抑制神经细胞的凋亡;HBO治疗7d对神经细胞凋亡的抑制作用最明显。     

急性一氧化碳中毒致心肌损害临床研究

目的研究急性一氧化碳（CO）中毒对心脏的损害。方法选择急诊入院的急性CO中毒患者102例,分为轻度、中度和重度中毒组,同时在健康体检人群中随机选择100例健康人为对照组。中毒组的病例入院24h采静脉血测定心肌酶及行心电图检查;对照组清晨抽空腹静脉血．测定心肌酶并完成12导联心电图描记。结果急性CO中毒患者中有63例血清心肌酶谱改变,占61.77％。中、重度中毒者多有不同程度的心肌酶升高,与健康对照组相比,差异有统计学意义（P〈0．01）;重、中度中毒组相比。差异亦有统计学意义（P〈0．01）。心电图异常改变有70例．占68．63％。经治疗,除2例病重无康复外．其余100例均康复出院．在CO中毒纠正后心肌酶和心电图均恢复正常。蛄论急性CO中毒不仅对神经系统造成损害．对心脏的损害也较严重,需要给予相应的治疗.     

The Effect of Fatal Carbon Monoxide Poisoning on the Surface Charge of Blood Cells

The objective of this investigation was to evaluate postmortem changes of electric charge of human erythrocytes and thrombocytes after fatal carbon monoxide (CO) poisoning. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells carried out at various pH values of electrolyte solution. The surface charge of erythrocyte membranes after fatal CO poisoning as well as after sudden unexpected death increased compared to the control group in the whole range of experimental pH values. Also, a slight shift of the isoelectric point of erythrocyte membranes to high pH values was observed. The surface charge of thrombocyte membranes after fatal CO poisoning decreased at low pH compared to the control group. However, at high pH, the values increased compared to the control group. The isoelectric point of thrombocyte membranes after fatal CO poisoning was considerably shifted toward low pH values compared to the control group. The observed changes are probably connected with the destruction of blood cell structure.     

Carbon monoxide-mediated brain lipid peroxidation in the rat

Clinical and animal data suggest that the pathogenesis of CO poisoning extends beyond the inhibition of hemoglobin function, but no mechanism has been identified. Evidence of neurological compromise, particularly loss of consciousness, has been implicated as a marker for increased mortality and morbidity in clinical reports. Experiments were carried out with rats to assess whether CO exposure may cause brain lipid peroxidation. With the use of two methods, measurement of conjugated dienes and thiobarbituric acid reactivity, brain lipid peroxidation could be documented as a result of exposure to CO at a concentration sufficient to cause unconsciousness. Products of lipid peroxidation were increased by 75% over the base-line values 90 min after CO exposure. Unconsciousness was associated with a brief period of hypotension, so brief that in itself it caused no apparent insult. Lipid peroxidation occurred only after the animals were returned to CO-free air, and there was no direct correlation with the carboxyhemoglobin level. This work may provide an explanation for a number of currently poorly understood clinical observations regarding CO poisoning.     

Does granulocyte colony stimulating factor have protective effects against carbon monoxide-induced apoptosis?

Carbon monoxide (CO) produced by incomplete combustion of hydrocarbons, has many toxic effects on different organs, especially the heart and brain that have greater demands for oxygen. The present study aimed to evaluate the protective effects of granulocyte colony stimulating factor (G-CSF) on apoptosis after CO poisoning in rats. Male Wistar rats were exposed to CO 1500 or 3000 ppm for 60 min. Single and multiple doses of G-CSF (10, 50, and 100 μg/kg) were administered to animals. After CO poisoning, carboxyhemoglobin concentration was measured, apoptotic cells were evaluated by TUNEL assay and caspase 3 activity was determined by immunofluorescence. Blood levels of carboxyhemoglobin significantly increased following exposure to both 1500 and 3000 ppm concentrations of CO. However, carboxyhemoglobin levels were significantly higher following exposure to CO 3000 ppm compared to CO 1500 ppm (p?<?0.05). Differences in caspase 3 activity between G-CSF and control groups were significant and G-CSF could decrease apoptosis following CO 3000 ppm poisoning (p?<?0.001). TUNEL assay showed that in rats treat with 5 doses of G-CSF 100 μg/kg, apoptosis was significantly ameliorated compared to control rats and sham (rats that were not exposed to CO) group (p?<?0.05). Concerning caspase 3 activity and apoptosis rate, the best results were found in rats exposed to 3000 ppm and treated with G-CSF 100 μg/kg. In this study, we confirmed that CO poisoning leads to cardiomyocytes apoptosis which could be significantly reduced by G-CSF treatment.     

Nogo-A蛋白在一氧化碳中毒大鼠海马组织中的动态表达

目的:观察一氧化碳中毒后大鼠海马组织中Nogo-A蛋白动态表达情况,探讨Nogo-A蛋白在一氧化碳中毒后神经系统损伤中的作用与影响。方法:随机数字法将雄性SD大鼠30只分为正常对照组(NC组)、CO中毒组(CO组)、CO中毒后24小时组(CO-24h)、CO中毒后48小时组(CO-48h)、CO中毒后7天组(CO-7d),每组各6只。CO气体腹腔注射染毒法建立一氧化碳中毒模型。建模后不同时间点利用免疫组织化学染色(IHC)、蛋白质免疫印迹技术检测(WB)Nogo-A蛋白在海马组织中的表达情况并分析其变化规律。结果:IHC结果表明NC、CO组、CO-24h组、CO-48h组、CO-7d组中Nogo-A蛋白平均光密度值分别为0.0928±0.0038、0.01172±0.0042、0.1452±0.0056、0.1271±0.0057、0.1088±0.0055;WB结果提示一氧化碳中毒后海马组织中Nogo-A蛋白的表达较NC组增高,在24h时表达达到高峰(P0.05);24h后表达开始逐步下降,至染毒第7天时,海马组织中Nogo-A蛋白的表达明显下降,但仍高于NC组(P0.05)。结论:在本研究中,大鼠海马组织中Nogo-A蛋白表达的增高与一氧化碳中毒相关;Nogo-A蛋白表达在24h时表达达到高峰;24h后表达开始逐步下降。     

Neuroprotective Effects of Erythropoietin in Patients with Carbon Monoxide Poisoning

The purpose of this study was to evaluate the efficacy of erythropoietin (EPO) for treating patients with carbon monoxide (CO) poisoning. We conducted a randomized, prospective study of 103 patients with CO poisoning in two groups: an EPO group (n = 54; patients received EPO) and a placebo group (n = 49; patients received normal saline). The study endpoints were the functional outcome at day 30 (the Barthel index and neurologic sequelae), National Institutes of Health Stroke Scale (NIHSS) score, and the levels of S‐100β. At 18 days, the NIHSS score improved significantly and S‐100β levels significantly decreased in patients in the EPO group. At 30 days, patients in the EPO group had a superior Barthel index and fewer patients had delayed neurologic sequelae (DNS). This study demonstrated that early administration of EPO to patients with CO poisoning improved neurological outcomes and reduced the incidence of DNS. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:266‐271, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21484     

Dexamethasone therapy for preventing delayed encephalopathy after carbon monoxide poisoning

We investigated dexamethasone therapy for preventing delayed encephalopathy after carbon monoxide (CO) poisoning. Eighty healthy male rats were exposed to CO and randomly divided into four groups: hyperbaric oxygen treatment (H), treatment (D), combined hyperbaric and dexamethasone treatment (C), and a control (M) group in which the rats inhaled CO to coma in the hyperbaric oxygen chamber, then were removed without further treatment. Twelve rats were put into the hyperbaric oxygen chamber and treated with air for 60 min (N) group. An eight arm maze was used to evaluate cognitive and memory abilities of these mice. Serum myelin basic protein (MBP) levels were evaluated using ELISA, and magnetic resonance imaging was used to observe brain demyelination and morbidity associated with delayed encephalopathy. A sample of the hippocampus from each group was examined by light microscopy. Cognitive and memory functions decreased in the control group M. Three days after CO poisoning, the serum MBP level of each group increased significantly. On Day 10 after CO poisoning, the MBP levels in groups C and D decreased significantly, but returned to normal on Day 18. MBP levels in the M and H groups were elevated at all time points. Brain MRIs showed significant differences among C, D, H and control M groups. Hematoxylin & eosin staining of the hippocampus showed greater damage in the control M and H groups. Early dexamethasone treatment may be useful for preventing delayed encephalopathy after CO poisoning and may reduce serum MBP levels.     

Unerwartete Kohlenmonoxid‐Gefahren

Unexpected carbon monoxide poisonings The poisonous gas carbon monoxide (CO) is not only produced as a result of combustion processes but can also be inhaled during the operation of barbecues, the smoking of water pipes, or in wood pellet stores. Inhalation of carbon monoxide can lead to life‐threatening or chronic poisoning. The present article provides information on the formation and effects of CO in domestic settings, and gives advice on how instances of poisoning can be avoided.     

Chelation therapy for methylmercury(II) poisoning. Synthesis and determination of solubility properties of MeHg(II) complexes of thiol and dithiol antidotes

Methylmercury(II) complexes of the most widely studied antidotes for mercury poisoning have been prepared, and both the water solubility and 1-octanol/water partition coefficients determined for these complexes and the L-cysteine complex. New complexes of N-acetyl-D,L-penicillamine, 2-mercaptosuccinic acid, meso-dimercaptosuccinic acid, and Unithiol have been synthesized and characterized, and are found to have the formulations MeHgSCMe2CH(NHCOMe)CO2H, MeHgSCH(CO2H)CH2CO2H, MeHgSCH(CO2H)CH(CO2H)SHgMe, and Na[MeHgSCH2CH-(SHgMe)CH2SO3], respectively. Trends in octanol/water partition coefficients are consistent with reported studies of the effectiveness of antidotes for MeHg(II) poisoning and redistribution of MeHg(II) on administration of antidotes, particularly for British anti-Lewisite, Unithiol, and meso-dimercaptosuccinic acid.     

Risk Factors for Non-Occupational Carbon Monoxide Poisoning: Anshan Prefecture,Liaoning Province,China, 2011–2012

Background

Carbon monoxide (CO) poisoning can be fatal but is preventable. From October 2010 to February 2011, Anshan Prefecture reported 57 cases of non-occupational CO poisoning in District A, with two deaths. We conducted an investigation to identify risk factors and recommend preventive measures.

Methods

We defined a possible case of non-occupational CO poisoning as onset of at least two of the following symptoms: fatigue, headache, dizziness, nausea, vomiting, cyanosis, loss of consciousness, coma, and shock from October 1, 2010, to February 28, 2011, in a resident of Anshan Prefecture with non-occupational exposure to CO poisoning. We defined a probable case as onset of at least one of the following symptoms: cyanosis, loss of consciousness, coma and shock, plus at least one of the following symptoms: fatigue, headache, dizziness, nausea, vomiting, among possible cases. A confirmed CO poisoning case was a possible case or probable case plus hemoglobin (Hb) CO higher than 10%. We searched for cases by reviewing medical records and records of hyperbaric oxygen tank usage. In a case-control investigation, we compared home heating practices of 30 case-persons and 120 control-persons who were individually matched to each case by neighborhood.

Results

Overall, 56% (39/70) of case-patients’ households burned coal for home-heating. In the case-control investigation, 40% (12/30) of case-persons’ households compared with 5.8% (7/120) of control-persons’ households placed stoves in bedrooms (Mantel-Haenszel odds ratio [OR_M-H] = 11, 95% confidence interval [CI] = 3.0–41); 53% (16/30) of case-patients’ households and 33% (40/120) of control-patients’ households did not extinguish the fire before sleeping (OR_M-H = 3.6, 95% CI = 1.1–12); 13% (4/30) of case-patients’ households and 3% (4/120) of control-patients’ households had not installed the ventilation pipe vertically (OR_M-H = 7.3, 95% CI = 1.0–56). Overall, 77% (23/30) of case-patients’ households and 39% (47/120) of control-patients’ households had at least one of those three risk factors (OR_M-H = 10, 95% CI = 2.5–40; population attributable risk percentage: 78%).

Conclusions

Dangerous practices with coal-burning stoves inside the home accounted for the majority of CO poisoning incidents. Community health centers should provide instruction to and supervision of residents on proper installation and use of home heating stoves as well as inspection of installation.     

Molecular-biological effect of thallium carbonate

The action of thallium carbonate (Tl2CO3) on rat embryonic cells was evaluated in accordance with the criterion for the formation of DNA breaks and chromosome aberrations, survival and mutagenicity of smallpox vaccine virus in these cells and on the basis of the frequency of dominant mutations in rats. Tl2CO3 produces DNA breaks whose restoration during 24 hours postincubation depends on the agent concentration. As the survival of smallpox vaccine virus exposed to Tl2CO3 decreases by a factor of 10(1) the virus mutagenicity rises 3fold. Tl2CO3 also possesses marked mutagenic activity as measured from the formation of chromosome aberrations. In the course of Tl2CO3 poisoning of males (for 8 months), followed by mating with intact females, there was a tendency to the increased total embryonic lethiality.     

Carboxyhemoglobin formation following smoke inhalation injury in sheep is interrelated with pulmonary shunt fraction

Carboxyhemoglobin (COHb) formation is triggered by the inducible isoform of heme oxygenase (HO-1) catalyzing carbon monoxide (CO) production through breakdown of heme molecules, exposure to CO or both. In the setting of CO poisoning, COHb is regarded as a reliable marker characterizing both severity of injury and efficacy of treatment strategies. This study was designed as a prospective laboratory experiment to elucidate potential interdependencies between COHb generation, oxygenation, and pulmonary shunt fraction (Qs/Qt) in an ovine model of smoke inhalation injury. Chronically instrumented ewes (n=15) were repeatedly subjected to cotton smoke (4 x 12 breaths) according to an established protocol. This approach resulted in a progressive increase in COHb formation that was interrelated with the degree of Qs/Qt (P<0.001) and inversely correlated with both arterial and mixed venous HbO(2) saturation (r=-0.96 and -0.93). Although the arteriovenous COHb gradient successively decreased over time, COHb determined in venous blood underestimated the arterial content.     

Electrocardiographic Changes in Amitriptyline Poisoning

In imipramine and amitriptyline poisoning the electrocardiographic abnormalities comprise arrhythmias, widening of the QRS complex, and marked changes in die S–T segment. These features were found to be of value in the differential diagnosis of unknown poisoning. The unusual configuration of qR with raised S–T segment in V1, simulating myocardial infarction, was seen in one of our patients and has been noted in four cases reported by other workers.     

Metabolic changes during carbon monoxide poisoning: An experimental study

Carbon monoxide (CO) is the leading cause of death by poisoning worldwide. The aim was to explore the effects of mild and severe poisoning on blood gas parameters and metabolites. Eleven pigs were exposed to CO intoxication and had blood collected before and during poisoning. Mild CO poisoning (carboxyhaemoglobin, COHb 35.2 ± 7.9%) was achieved at 32 ± 13 minutes, and severe poisoning (69.3 ± 10.2% COHb) at 64 ± 23 minutes from baseline (2.9 ± 0.5% COHb). Blood gas parameters and metabolites were measured on a blood gas analyser and nuclear magnetic resonance spectrometer, respectively. Unsupervised principal component, analysis of variance and Pearson's correlation tests were applied. A P-value ≤ .05 was considered statistically significant. Mild poisoning resulted in a 28.4% drop in oxyhaemoglobin (OHb) and 12-fold increase in COHb, while severe poisoning in a 65% drop in OHb and 24-fold increase in COHb. Among others, metabolites implicated in regulation of metabolic acidosis (lactate, P < .0001), energy balance (pyruvate, P < .0001; 3-hydroxybutyrc acid, P = .01), respiration (citrate, P = .007; succinate, P = .0003; fumarate, P < .0001), lipid metabolism (glycerol, P = .002; choline, P = .0002) and antioxidant-oxidant balance (glutathione, P = .03; hypoxanthine, P < .0001) were altered, especially during severe poisoning. Our study adds new insights into the deranged metabolism of CO poisoning and leads the way for further investigation.