Fatal inhalation of volcanic gases in three tourists of a geothermal area.

The study reports the environmental, toxicological and histopathological forensic investigations applied on three victims of accidental death (father, mother and son), due to the fall in a volcanic pothole, during the touristic visit of the "Solfatara park", near Naples (Italy). At autopsy greenish skin discolouration was observed and all bodies showed the classical signs of asphyxial deaths, such as cyanosis and hemorrhagic pulmonary edema. Focal micro-hemorrhages were found in the brain at intracranial and subpial levels. The hemogasanalysis and spectrophotometric test on blood for Methemoglobin (MetHb), Carboxyhemoglobin (HbCO) and Sulfhemoglobin (SHb) showed pCO2, SHb and MetHb above the physiological levels. On biological specimens, toxicological analyses performed by GC/MS revealed high concentrations of hydrogen sulfide (H2S) and of thiosulfate (TS), its main metabolite. The monitoring of toxic gases on the death scene showed an unsafe environment, into the pothole, able to cause the sudden loss of consciousness of the victims with subsequent asphyxiation (knockdown effect). In particular, at the bottom of the hole, the maximum levels of H2S and carbon dioxide (CO2) were 2200 ppm and 98% respectively. For the family members, the cause of the death was assessed as acute poisoning by H2S and CO2. The fatalities, happened in quick succession as for a domino effect, were pretty similar to the asphyxial deaths by confined spaces, frequently observed in occupational setting. Fatalities secondary to accidental volcanic gases inhalation, such as H2S and CO2 in geothermal areas, have been already described but often without a forensic approach. To the best of our knowledge this is the first case that reports the accidental poisoning by volcanic gases involving three people, with different caracteristic of age and sex, allowing the correlation between toxicological and pathological results with the true levels of asphyxiating gas, measured on the death scene.

Assessment of muscular energy metabolism and heat shock response of the green abalone Haliotis fulgens (Gastropoda: Philipi) at extreme temperatures combined with acute hypoxia and hypercapnia.

The interaction between ocean warming, hypoxia and hypercapnia, suggested by climate projections, may push an organism earlier to the limits of its thermal tolerance window. In a previous study on juveniles of green abalone (Haliotis fulgens), combined exposure to hypoxia and hypercapnia during heat stress induced a lowered critical thermal maximum (CTmax), indicated by constrained oxygen consumption, muscular spams and loss of attachment. Thus, the present study investigated the cell physiology in foot muscle of H. fulgens juveniles exposed to acute warming (18 °C to 32 °C at +3 °C day-1) under hypoxia (50% air saturation) and hypercapnia (~1000 µatm PCO2), alone and in combination, to decipher the mechanisms leading to functional loss in this tissue. Under exposure to either hypoxia or hypercapnia, citrate synthase (CS) activity decreased with initial warming, in line with thermal compensation, but returned to control levels at 32 °C. The anaerobic enzymes lactate and tauropine dehydrogenase increased only under hypoxia at 32 °C. Under the combined treatment, CS overcame thermal compensation and remained stable overall, indicating active mitochondrial regulation under these conditions. Limited accumulation of anaerobic metabolites indicates unchanged mode of energy production. In all treatments, upregulation of Hsp70 mRNA was observed already at 30 °C. However, lack of evidence for Hsp70 protein accumulation provides only limited support to thermal denaturation of proteins. We conclude that under combined hypoxia and hypercapnia, metabolic depression allowed the H. fulgens musculature to retain an aerobic mode of metabolism in response to warming but may have contributed to functional loss.

A Fatal Case of Gas Intoxication in Silage Pit.

Fatalities due to gas intoxication are rare in routine forensic casework. The most common gas is carbon monoxide, with other gases (ammonia, methane, propane and butane, carbon dioxide, hydrogen sulfide) encountered only very rarely. In this report, we describe the accidental death of two maintenance workers who were found in the silage pit at a biogas plant. The autopsy revealed signs of asphyxia in both the deceased. Analysis of the gaseous mixtures in the tank using an infrared gas analyzer showed slightly elevated concentrations of carbon dioxide. Toxicological examination of the blood of both the deceased using gas chromatography with a flame ionization detector, spectrophotometry and liquid chromatography-mass spectrometry did not detect any toxicologically significant substance that would explain the sudden collapse. Both the autopsy and the toxicology analyses suggest CO2 intoxication as the most likely cause for the collapse of the two men, which then led to sudden asphyxia.

The Choice of Euthanasia Method Affects Metabolic Serum Biomarkers.

The impact of euthanasia methods on endocrine and metabolic parameters in rodent tissues and biological fluids is highly relevant for the accuracy and reliability of the data collected. However, few studies concerning this issue are found in the literature. We compared the effects of three euthanasia methods currently used in animal experimentation (i.e. decapitation, CO2 inhalation and pentobarbital injection) on the serum levels of corticosterone, insulin, glucose, triglycerides, cholesterol and a range of free fatty acids in rats. The corticosterone and insulin levels were not significantly affected by the euthanasia protocol used. However, euthanasia by an overdose of pentobarbital (120 mg/kg intraperitoneal injection) increased the serum levels of glucose, and decreased cholesterol, stearic and arachidonic acids levels compared with euthanasia by CO2 inhalation and decapitation. CO2 inhalation appears to increase the serum levels of triglycerides, while euthanasia by decapitation induced no individual discrepant biomarker level. We conclude that choice of the euthanasia methods is critical for the reliability of serum biomarkers and indicate the importance of selecting adequate euthanasia methods for metabolic analysis in rodents. Decapitation without anaesthesia may be the most adequate method of euthanasia when taking both animal welfare and data quality in consideration.

Expression of mRNA in the frontal cortex and hypothalamus in a rat model of acute carbon dioxide poisoning.

Acute carbon dioxide (CO2) poisoning causes no specific features that are revealed upon autopsy, and the pathophysiological mechanism of this syndrome is unclear. To address this issue, in the present study, we exposed rats to CO2 concentrations ranging from 10% to 60% and determined the effects on mRNA expression. According to the results of Gene Ontology (GO) and cluster analyses of microarrays data, we selected the following genes for further analysis: alkylglycerone phosphate synthase (Agps), hypocretin (Hcrt), tyrosine hydroxylase (Th), heat shock protein beta 2 (Hspb2), and opioid receptor delta 1 (Oprd1) expressed in the frontal cortex and renin (Ren), pancreatic polypeptide (Ppy), corticotropin releasing hormone receptor 2 (Crhr2), carbonic anhydrase 1 (Car1), and hypocretin receptor 1 (Hcrtr1) expressed in the hypothalamus. We found significant differences between the expression levels of Agps and Hspb2 mRNAs in the frontal cortex and that of Ppy, Crhr2 mRNAs in the hypothalamus in the presence of high concentrations of CO2. Further investigation of these genes may clarify the pathophysiology of acute CO2 poisoning and facilitate the development of novel forensic tests that can diagnose the cause of death.

Buildings' integral role in good health.

As reported in last month's HEJ, the new Sustainable Development Strategy for the Health, Public Health and Social Care System for 2014-20 rightly emphasises the importance of the built environment to health and well-being. Chris Hall, the BRE's health sector lead, says this message 'stretches far beyond hospitals and healthcare buildings into the communities and homes that people live in'. Here he highlights some of the key elements relating to the current carbon efficiency of healthcare buildings, considers the impact of 'good' housing on health and preventing illness, and looks forward to a series of joint IHEEM and BRE 'Building Sustainable Development' mini-conference events planned in the run-up to October's Healthcare Estates 2014 event in response to the new Strategy, designed to share ideas and good practice on sustainable estates issues. The first takes place in London later this month (see panel below).

Exposure of unsuspecting workers to deadly atmospheres in below-ground confined spaces and investigation of related whole-air sample composition using adsorption gas chromatography.

Hazardous atmospheres in confined spaces may be obvious when a source of air contamination or oxygen (O2) deficiency is recognized. Such is often the case in general industry settings, especially with work processes which create hazardous atmospheres that may be anticipated. Hazards present in active sewers are also well recognized; but the possibility that O2 deficiency or high airborne contaminant concentrations may exist in new construction sewers or storm drains has been repeatedly ignored with deadly results. Low O2 and high carbon dioxide (CO2) concentrations may exist in new construction manholes that have not yet been connected to an active sewer or drain system, and these concentrations have been shown to vary over time. A recent incident is described where workers repeatedly entered such a confined space without incident, but subsequent entry resulted in a fatality and a near-miss for a co-worker rescuer. Additional cases are discussed, with an emphasis placed on elevated CO2 concentrations as a causative factor. A description is provided for the adsorptive gas chromatography whole-air analysis methodology used to quantitatively determine atmospheric conditions present at this type of fatality site or others after an incident, and for the gas chromatography-mass spectrometry method used to provide confirmation of analyte identity with high certainty. Many types of confined spaces may be encountered in addition to the underground varieties discussed, and many possible atmospheric hazards are possible. The definitive whole-air analysis approach described here may be of use and should be considered to investigate many confined space fatality and near-miss cases, and to better understand the causes of dangerous atmosphere conditions that may arise in confined spaces.

Murder-suicide by carbon dioxide (CO2) poisoning: a family case from Berlin, Germany.

This report demonstrates how carbon dioxide (CO(2)) may be a potent weapon in murder-suicide, where the death scene offers virtually no clues as to the lethal modality and the autopsy findings are nonspecific. Four bodies were discovered in an apartment in midsummer 2012 in Berlin, Germany. The bodies were those of a father (a 69-year-old business consultant), his wife (aged 26-years), and two sons (aged 3 and 6 years, respectively). The police found the wife and two sons lying in their beds and the husband in a supine position on the floor with a plastic bag over his head tied loosely around his neck with a rope. A 500 g single-use CO(2) cylinder was standing on the floor. The container was almost empty and according to the label had been sold as a CO(2)-fertilizer for aquarium plants. Two synthetic inhalation face masks and tubing were also found, which tested positive for the DNA of all four deceased family members. It is hypothesized that the husband placed an inhalation mask over the mouths and noses of his wife and children while they were sleeping. Inhalation of pure CO(2) ensured their rapid unconsciousness due to hypercapnia and severe anoxia. The rapid increase in CO(2) concentration would render a victim helpless, with no time to wake and defend themselves, or others. The proximate cause of death in all cases was attributed to CO(2) intoxication, based on the scene findings, the reconstructed sequence of events, the autopsy, and results of toxicological studies.

Suicide by carbon dioxide.

Suicides by self-poisoning are common in all parts of the world. Among these intoxications, gases are rarely used, especially carbon dioxide (CO2). Very few cases of self-inflicted and deliberate carbon dioxide poisonings have been reported. This paper presents two uncommon suicides by carbon dioxide intoxication. In one case, a 53-year-old man tightly sealed a small bathroom and locked himself in it likely with dry ice. Warning notices were tagged to the door. In another case, a 48-year-old man working in a restaurant committed suicide by closing himself in a walk-in refrigerator and opening the stored carbon dioxide containers intended for the beverage dispensing equipment. The limited possibilities of proving lethal CO2 intoxications post-mortem necessitate a close cooperation of the involved parties during investigation. Only the synopsis of all findings permits a sound assessment regarding the manner and cause of death.

Harnessing natural ventilation benefits.

Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

Fatality in a wine vat.

Intoxication with carbon dioxide (CO2), a nonexplosive, colorless, and odorless gas does not cause any clinical symptoms or signs, with the occasional exception of sudation. Carbon dioxide is principally used in the food industry (70% of CO2 production), in particular to preserve foods and to carbonate beverages. Most fatalities resulting from CO2 intoxication are accidental and occur either in closed spaces or when dry ice is used in the food industry. In this case report, a 42-year-old male winemaker engineer was found dead, his head inside a wine vat that had been filled with grapes on the previous day and supplemented with dry ice to improve the taste of wine.

A fatal case of CO(2) intoxication in a fermentation tank.

Carbon dioxide (CO2 ) is an odorless constituent of air. Higher concentrations can be detected in geothermal and automotive emissions, fermentation, and sublimation of dry ice. An unskilled worker entered a fermentation tank to clean it, which had not been done for about 5 months allowing for high concentrations of CO2 to build up. A second worker entered the tank to rescue the first one. Shortly after both were found the first worker was rescued directly whereas the tank had to be rotated to pull the second worker out. Cardiopulmonary resuscitation was successful only for the first worker. Medico-legal autopsy showed bruises, hematoma, myocardial hemorrhage, and edema of the lungs. The right lung was vacuum degassed in an argon atmosphere and quadrupole-mass-spectrometry showed an elevated CO2 content in lung gases. Thus, CO2 intoxication/asphyxia in a vitiated atmosphere due to fermentation of wine mash was established as the cause of death.

Toxic CO-ingestions in intentional carbon monoxide poisoning.

BACKGROUND: Intentional carbon monoxide (CO) poisoning is responsible for two-thirds of the deaths from CO poisoning in this country and an estimated 15,000 Emergency Department visits annually. OBJECTIVES: In an attempt to optimize medical management of such patients, this study was conducted to examine the frequency and types of toxic co-ingestions that may accompany CO inhalation. METHODS: Records of all patients treated with hyperbaric oxygen for acute, intentional CO poisoning at a regional referral center for hyperbaric medicine in Seattle from 1980 to 2005 were reviewed. For those where co-ingestions were identified, information about type of poison(s) and results of toxicology screens was recorded and analyzed. RESULTS: Over the 25-year period examined, 433 patients were treated for intentional CO poisoning and records were available for 426. Of those, 188 (42%) had ingested one or more poisons in addition to CO. Ethanol was most common, but a wide variety of other drug classes were also identified. Toxicology screening studies of some type were performed in 49 patients. CONCLUSIONS: Toxic co-ingestions seem to be relatively common in patients treated for intentional CO poisoning. For this reason, providers should be vigilant and open to clinical signs that can't be explained with CO exposure alone, and ready to treat clinical issues that arise from co-ingestions.

Effect of classroom air quality on students' concentration: results of a cluster-randomized cross-over experimental study.

UNLABELLED: To assess the effect of indoor air quality as indicated by the median carbon dioxide (CO2) level in the classroom on the concentration performance (CP) of students, a cross-over cluster-randomized experimental study was conducted in 20 classrooms with mechanical ventilation systems. Test conditions 'worse' (median CO2 level on average 2115 ppm) and 'better' (median CO2 level on average 1045 ppm) were established by the regulation of the mechanical ventilation system on two days in one week each in every classroom. Concentration performance was quantified in students of grade three and four by the use of the d2-test and its primary parameter 'CP' and secondary parameters 'total number of characters processed' (TN) and 'total number of errors' (TE). 2366 d2-tests from 417 students could be used in analysis. In hierarchical linear regression accounting for repeated measurements, no significant effect of the experimental condition on CP or TN could be observed. However, TE was increased significantly by 1.65 (95% confidence interval 0.42-2.87) in 'worse' compared to 'better' condition. Thus, low air quality in classrooms as indicated by increased CO2 levels does not reduce overall short-term CP in students, but appears to increase the error rate. PRACTICAL IMPLICATIONS: This study could not confirm that low air quality in classrooms as indicated by increased CO2 levels reduces short-term concentration performance (CP) in students; however, it appears to affect processing accuracy negatively. To ensure a high level of accuracy, good air quality characterized, for example, by low CO2 concentration should be maintained in classrooms.

Sedation or inhalant anesthesia before euthanasia with CO2 does not reduce behavioral or physiologic signs of pain and stress in mice.

CO(2) administration is a common euthanasia method for research mice, yet questions remain regarding whether CO(2) euthanasia is associated with pain and stress. Here we assessed whether premedication with acepromazine, midazolam, or anesthetic induction with isoflurane altered behavioral and physiologic parameters that may reflect pain or stress during CO(2) euthanasia. Mice were assigned to 1 of 6 euthanasia groups: CO(2) only at a flow rate of 1.2 L/min which displaces 20% of the cage volume per minute (V/min; control group); premedication with acepromazine (5 mg/kg), midazolam (5 mg/kg), or saline followed by 20% V/min CO(2); induction with 5% isoflurane followed by greater than 100% V/min CO(2) (>6L/min); and 100% V/min CO(2) only (6 L/min). Measures included ultrasonic sound recordings, behavioral analysis of video record- ings, plasma ACTH and corticosterone levels immediately after euthanasia, and quantification of c-fos from brain tissue. Compared with 20% V/min CO(2) alone, premedication with acepromazine or midazolam did not significantly alter behavior but did induce significantly higher c-fos expression in the brain. Furthermore, the use of isoflurane induction prior to CO(2) euthanasia significantly increased both behavioral and neuromolecular signs of stress. The data indicate that compared with other modalities, 20% V/min CO(2) alone resulted in the least evidence of stress in mice and therefore was the most humane euthanasia method identified in the current study.

Physiological and affective reactivity to a 35% CO2 inhalation challenge in individuals differing in the 5-HTTLPR genotype and trait neuroticism.

The inhalation of 35% carbon dioxide (CO2) results in an acute stress response in healthy individuals and may accordingly provide a good paradigm to examine potential vulnerability factors for stress reactivity and stress-related psychopathology. It has been proposed that CO2 reactivity is moderated by genetic (5-HTTLPR) and personality (neuroticism) factors, yet no experimental study has investigated their effects on CO2 reactivity simultaneously. The current study examined the singular and interactive effects of the 5-HTTLPR genotype and neuroticism in predicting the affective and physiological response to a 35% CO2 challenge in a healthy sample of male and female students. From a large group of 771 students, 48 carriers of the low/low expressing allele (S/S, S/Lg, Lg/Lg) and 48 carriers of the high/high expressing allele (La/La) with the lowest and the highest neuroticism scores (77 females, 19 males; mean age ± SD: 20.6 ± 2 years) were selected and underwent a 35% CO2 inhalation. Visual analogue scales for anxiety and discomfort and the Panic Symptom List were used to assess affective symptomatology, while salivary samples and heart rate were assessed to establish the physiological response. A typical pattern of responses to CO2 was observed, characterised by increases in anxiogenic symptoms and physical panic symptomatology and a reduction in heart rate; however, no effect on salivary cortisol concentration was observed. Additionally, the CO2 reactivity did not differ between groups divided by the 5-HTTLPR genotype or neuroticism. Findings of the current study do not support a role for singular or interactive effects of the 5-HTTLPR genotype and trait neuroticism on affective and physiological reactivity to a 35% CO2 inhalation procedure.

Study on the effect of different oxygen therapies on rats with acute carbon dioxide poisoning.

OBJECTIVE: To study the effect of different oxygen therapies on the rats with carbon dioxide poisoning for screening out the best on-the-spot oxygen-therapy technology for treating acute carbon dioxide poisoning. METHODS: The 60 healthy male Sprague Dawley rats were randomly divided into normal control group (A group), carbon dioxide poisoning group (B group), low-concentration oxygen inhalation treatment group (C group), high-concentration oxygen inhalation treatment group (D group) and hyperbaric oxygen-therapy group (E group). Various kinds of oxygen therapies were given after the contamination. The pH, partial pressure of oxygen (PO(2)) and partial pressure of carbon dioxide (PCO(2)) of arterial blood, serum troponin I (CTNI), creatine kinase (CK), glutamic-oxaloacetic transaminase (AST), γ-glutamyl transpeptidase (GGT), blood urea nitrogen (BUN), potassium (K), sodium (Na) and chlorine (Cl) for the rats of each group were inspected. The lung and the brain tissues were taken for observing the pathological changes. RESULTS: There is no significant difference in pH, PO(2) and PCO(2) among all oxygen-therapy groups (p > 0.05). The levels of CTNI, CK and AST in E group are obviously lower than that in B, C and D groups (p < 0.05). The level of serum K in E group is obviously lower than that in B, C and D groups (p < 0.05). The levels of serum Na and Cl in E group are obviously higher than that in B, C and D groups (p < 0.05). The pathological change of lungs in E group is significantly better than that in C and D groups. CONCLUSIONS: We recommend that the medical units with related conditions can give the hyperbaric oxygen therapy to patients as soon as possible.

Canopy processes in a changing climate.

Forest canopies exchange a large part of the mass and energy between the earth and the atmosphere. The processes that regulate these exchanges have been of interest to scientists from a diverse range of disciplines for a long time. The International Union of Forest Research Organizations (IUFRO) Canopy Processes Working Group provides a forum for these scientists to explore canopy processes at scales ranging from the leaf to the ecosystem. Given the changes in climate that are being experienced in response to rising [CO(2)], there is a need to understand how forest canopy processes respond to altered environments. Globally, native and managed forests represent the largest terrestrial biome and, in wood and soils, the largest terrestrial stores of carbon. Changing climates have significant implications for carbon storage in forests, as well as their water use, species diversity and management. In order to address these issues, the Canopy Processes Working Group held a travelling workshop in south-east Australia during October 2010 to examine the impact of changing climates on forest canopies, highlighting knowledge gaps and developing new research directions.