A forensic analysis on 53 cases of complex suicides and one complicated assessed at the Bureau of Legal Medicine of Milan (Italy).

Complex suicides are highly uncommon suicides in which multiple detrimental methods are used simultaneously or in chronological succession. We retrospectively analyzed through our database the 25512 autopsy reports registered at the Bureau of Legal Medicine of Milan in the last 27 years from 1993 until 2019, where 4498 suicides were documented. We assessed 53 cases of complex suicides and only one case of complicated suicide: for all of them we analyzed both data collected during the on-site investigation and the autopsy. In our case series, we identified a total number of 113 methods chosen and variably combined by the victims, which were classified into 17 categories. On the whole the most frequent association of suicide methods resulted in the combination of the plastic bag suffocation with inert gas inhalation (13 out of 53 complex suicides; 24.5%). We also analyzed our cases of simple suicides (1993-2019), to compare them with the complex suicides. In this study, we present a complete analysis regarding our cases of complex suicides, discussing the challenges and the interpretative issues which a forensic pathologist might deal with. A thorough on-site judicial inspection and a careful autopsy examination are crucial in such cases. Moreover, the clinical history of the victims and laboratory findings are supplemental elements to be necessarily considered to establish the actual manner of death and avoid any misinterpretations.

Deaths related to nitrogen inhalation: Analytical challenges.

Dinitrogen (N2) has been increasingly connected to suicidal deaths. The analysis of N2 in post-mortem cases still represents a major challenge in forensic toxicology and circumstantial data has so far played a major role for the determination of the cause of death. In this paper, after presenting a review of cases of N2 intoxication described in forensic literature, we report the application of two approaches in order to quantify an excess of N2 in post-mortem whole blood collected from a case of suicide by nitrogen inhalation. N2 analyses were performed by GC-MS on the suicidal case and on controls taken from 10 autopsy cases with similar PMI (5 traumatic deaths and 5 deaths by asphyxia). The percentage of N2 was estimated by building a five-point N2 peak area calibration curve (0, 15.6 %, 62.4 % 78.1 %, 100 %) and through an external QC, assessing linearity, accuracy and precision, LLOQ, specificity and stability of N2 in the sample vial. Percentage of N2 of the case was significantly higher than the post-mortem controls (p<0.05). The N2/O2 ratio of the case and controls was also calculated as an additional indicator, and was significantly higher in the case (p<0.05). The strengths and the limitation of both methods are reported in the paper. Toxicological confirmation for N2 are rarely performed when the cause of death is evident, probably due to the lack of validated methods and the complexity of the interpretation of N2 concentration in biological fluids. The presented methods can be rapidly and profitably applied with instrumentation normally available in forensic laboratories.

Fatal inhalation of nitrogen inside a closed environment: Toxicological issues about the cause of death.

Asphyxia due to inhalation of nitrogen, as accidental or suicidal event, has been seldom reported in the forensic field. Death usually occurs because of a displacement and decrease of environmental and alveolar oxygen concentrations, but taking into account that nitrogen is a normal component of atmosphere, autopsy findings, which may be in certain cases unremarkable, must be corroborated with a careful scene investigation in order to determine the cause of death. We present a case of a 37-year old male found unresponsive inside his car with five liquid nitrogen tanks placed in the trunk, three of them with clear losses because of incomplete lock. Resuscitation efforts were unsuccessful. Autopsy findings and histological analyses were unremarkable, but toxicological analyses were crucial. Percentages of nitrogen were high in blood collected from the inferior vena cava (85.2%), left ventricle (81.01%) and the right lung (80.73%). Concentrations of nitrogen were higher than those detected in control samples: 14 autopsy cases, room air and water. The cause of death was identified as an inert gas asphyxiation, which was classified as accidental in accordance with the police report.

Nitrogen inhalation suicide pacts.

Suicide pacts usually result in simultaneous deaths by mutual arrangement. While nitrogen and helium gas inhalation are being increasingly used in solitary suicide attempts, for some reason they have been rarely utilised in suicide pacts. A search of autopsy files at Forensic Science SA over a 15-year period (2003-2017) was undertaken to determine how often this method of joint suicide occurs. Only two cases were found. Case 1 comprised a 64-year-old husband and wife (who had a history of multiple sclerosis). They were found deceased in a vehicle with two empty cylinders of nitrogen gas. Case 2 comprised an 87-year-old man (who had a history of ischaemic heart disease) and his 81-year-old wife who were found deceased with plastic bags over their heads, with plastic tubes connecting the bags to opened cylinders of nitrogen. The deaths in all cases were due to nitrogen-induced asphyxiation, in the latter instance augmenting plastic-bag asphyxia. Although suicide pacts have previously usually involved carbon-monoxide toxicity or drug overdose, it is possible that dissemination of information on the use of inert gases in individual suicide attempts may alter the methods used in future.

Suicidal nitrogen inhalation by use of scuba full-face diving mask.

A 29-year-old man was found dead lying on the bed in a hotel room in a famous Slovak mountain resort. He had a full-face diving mask on his face, connected through a diving breath regulator to a valve of an industrial (nondiving) high-pressure tank containing pure 100% nitrogen. The breath regulator (open-circuit type) used allowed inhalation of nitrogen without addition of open air, and the full-face diving mask assured aspiration of the gas even during the time of unconsciousness. At autopsy, we found the typical signs of suffocation. Toxicological analysis revealed 94.7% content of nitrogen in alveolar air. Following the completion of the police investigation, the manner of death was classified as a suicide. Within the medico-legal literature, there has been only one similar case of suicidal nitrogen inhalation described.

A case of death of the driver due to environmental asphyxia by liquid nitrogen leakage in the cabin of the car during a road accident / Przypadek zgonu kierowcy na skutek wylania cieklego azotu w kabinie samochodowej podczas wypadku drogowego.

Nitrogen causes environmental asphyxia by displacing oxygen in the air leading to death. The study presents a case of a death of a driver death who was transporting flasks with liquid nitrogen that depressurized during an accident. The mechanism and cause of death were determined based on the result of the autopsy and histopathologic examination. The authors emphasize the relevance of accident scene inspection during establishing the cause of death in similar cases.

Case report of suicide by inhalation of nitrogen gas.

Nitrogen is an inert gas that is a normal constituent of the air that we breathe. It is a suffocating gas that does not support life and that can be a cause of death by the displacement of oxygen in the atmosphere. The majority of deaths associated with nitrogen have occurred in the setting of scuba diving. Although other suffocating gases have been used as a means of committing suicide, the literature contains little information about the use of nitrogen as a suicidal agent. A case of a 50-year-old man who committed suicide using a homemade suicide device and nitrogen gas is presented.

Humane killing of nonhuman animals for disease control purposes.

Reports and guidelines produced by international institutions such as the World Organization for Animal Health (OIE, 2005) describe various methods of killing nonhuman animals. Selection and implementation of a killing method may involve several factors. Preventing or minimizing risk to human health and safety may override animal welfare concerns if the disease has the potential to cause high mortality, for example, highly pathogenic avian influenza. Owing to the public health significance of this disease, the scope of this article presents only an overview of the welfare and practical aspects of large-scale killing of poultry on farms. Killing poultry in houses using a gas mixture eliminates the need for human contact with infective materials and birds. Several protocols for administering gas mixtures into poultry houses have been evaluated, mainly in Europe and North America. Overdose of anesthetics in feed and water has sedated birds kept under free-range or semi-intensive rearing systems. Containerized gas killing systems have proved successful on small-to-medium-size poultry farms. However, using nitrogen, a nonaversive gas, could greatly improve bird welfare.

Evaporated liquid nitrogen-induced asphyxia: a case report.

A 27-yr-old postgraduate student was found lying at the floor of an unsealed underground dry area, where a valve-opened empty cylinder of liquid nitrogen (150 L) was connected to a cap-removed empty Dewar-flask (10 L) via a copper infusion tube. No injury was found externally or internally. There were petechiae in the bilateral conjunctivae and periorbital skin. The dry area, measuring 300 x 130 x 260 cm, had a communication to the basement of the research building by a window measuring 90 x 60 cm in size at 130 cm above the floor. The scene reconstruction and atmosphere gas analysis revealed that the O2 concentration at 60 cm above the base dropped to 12.0% in 3 min and 10 sec, 10.0% in 8 min and 53 sec, 6.0% in 18 min and 40 sec, and 4.2% in 20 min and 28 sec. The primary cause of death was asphyxia by evaporated liquid nitrogen.

Evaporated Liquid Nitrogen-Induced Asphyxia: A Case Report

A 27-yr-old postgraduate student was found lying at the floor of an unsealed underground dry area, where a valve-opened empty cylinder of liquid nitrogen (150 L) was connected to a cap-removed empty Dewar-flask (10 L) via a copper infusion tube. No injury was found externally or internally. There were petechiae in the bilateral conjunctivae and periorbital skin. The dry area, measuring 300X130X260 cm, had a communication to the basement of the research building by a window measuring 90X60 cm in size at 130 cm above the floor. The scene reconstruction and atmosphere gas analysis revealed that the O2 concentration at 60 cm above the base dropped to 12.0% in 3 min and 10 sec, 10.0% in 8 min and 53 sec, 6.0% in 18 min and 40 sec, and 4.2% in 20 min and 28 sec. The primary cause of death was asphyxia by evaporated liquid nitrogen..

[Induction of hypoxia-inducible factor-1alpha in two kinds of rats asphyxiation death models].

OBJECTIVE: To investigate the expression of hypoxia-inducible factor 1-alpha (HIF1-alpha) in the heart, lung, liver and kidney in rats died of two typical models of asphyxia. METHODS: Two asphyxia models were made and tissue samples of the dead rats were collected from different groups at various postmortem duration. The expression and the changes of HIF1-alpha in various tissues were examined by immunohistochemistry and image analysis techniques. Results Significant expression of HIF1-alpha was observed in the myocardial fibers, kidney cells, liver cells and lung cells in both asphyxia models, but not in the control group. The expression of HIF1-alpha in various tissues in the rat died of nitrogen gas breathing was found in the nuclei at 0 hour and the expression level decreased gradually thereafter. The HIF1-alpha expression level and duration in various tissues of the rat died of hanging were higher and longer than that of the former group, with a peak of the expression level observed 6 hours after death, and then started to decline in all tissues except the heart where the expression still showed an increase 24 hours after death. The control groups showed a steady expression in the cytoplasm but not in the nuclei. CONCLUSION: HIF1-alpha appears to be a valuable biomarker in the diagnosis of asphyxia within 24 hours after death.

Induction of hypoxia-inducible factor-1alpha in two kinds of rats asphyxiation death models / 法医学杂志

OBJECTIVE@#To investigate the expression of hypoxia-inducible factor 1-alpha (HIF1-alpha) in the heart, lung, liver and kidney in rats died of two typical models of asphyxia.@*METHODS@#Two asphyxia models were made and tissue samples of the dead rats were collected from different groups at various postmortem duration. The expression and the changes of HIF1-alpha in various tissues were examined by immunohistochemistry and image analysis techniques. Results Significant expression of HIF1-alpha was observed in the myocardial fibers, kidney cells, liver cells and lung cells in both asphyxia models, but not in the control group. The expression of HIF1-alpha in various tissues in the rat died of nitrogen gas breathing was found in the nuclei at 0 hour and the expression level decreased gradually thereafter. The HIF1-alpha expression level and duration in various tissues of the rat died of hanging were higher and longer than that of the former group, with a peak of the expression level observed 6 hours after death, and then started to decline in all tissues except the heart where the expression still showed an increase 24 hours after death. The control groups showed a steady expression in the cytoplasm but not in the nuclei.@*CONCLUSION@#HIF1-alpha appears to be a valuable biomarker in the diagnosis of asphyxia within 24 hours after death.

Nitrogen deposition and the biodiversity of boreal forests: implications for the nitrogen critical load.

The critical load concept is used to establish the deposition levels which ecosystems can tolerate without significant harmful effects. Here we summarize work within the Swedish research program Abatement Strategies for Transboundary Air Pollution (ASTA) assessing the critical load of N for boreal forests. Results from both field experiments in an area with low background N deposition in northern Sweden, and from a large-scale monitoring study, show that important vegetational changes start to take place when adding low N doses and that recovery of the vegetation after ceasing N input is a very slow process. The data presented indicate that changes in key ecosystem components occur even at a lower rate of N input than the present recommended empirical critical load for boreal forest understorey vegetation of 10-15 kg N ha(-1) yr(-1). Based on the data presented, we suggest that the critical load should be lowered to 6 kg N ha(-1) yr(-1).

Environmental gas displacement: three accidental deaths in the workplace.

The authors describe three accidental deaths resulting from occupational hazards involving environmental gas alterations. One involved the displacement of oxygen caused by leakage of liquid nitrogen during the installation of a magnetic resonance imaging system. Two involved elevated environmental carbon dioxide concentrations: dry ice sublimation in a walk-in refrigerator in a research laboratory, and activation of a carbon dioxide fire alarm-extinguisher system by a woman locked in a bank vault. The autopsy findings, scene investigations, and certifications of these deaths, as related to the mechanisms of death, are discussed.

[Chemical obliterans bronchiolitis after azotic acid exposure]. / Bronsiolita obliteranta chimica dupa expunere la acid azotic.

The authors present the case of a 48 years old man having an exposure to irritant gases (azotic and lactic acids) in a closed space, inhaling them for 5 minutes. Shortly after the accident the patient displayed the signs of corneal and conjunctival burn; several days afterwards respiratory symptoms appeared: shortness of breath, dyspnea to minor efforts, then nocturnal dyspnea and orthopnea. Chest X-ray, CT scan, complex lung function tests and bronchoalveolar lavaje, together with the history of recent exposure to irritant gases led to the diagnosis of hypersensitivity obliterant bronchiolitis. Oral corticoids in dose of 60 mg/day determined a substantial clinical, radiological and functional improvement. The authors make some comments on the need of early diagnosis and efficient treatment.

Temporal changes in nitrogen pollution in northeastern Estonia.

During the last 5 decades the northeastern part of Estonia (the region where oil shale and the chemical industry are located) has been subjected to pollution with acidic compounds. In 1981-1988 the yearly mean nitrogen (N) deposition load was up to 11.1 kg ha(-1). This N pollution level combined with the deposition of sulphur (S) could have seriously endangered the environment, but the simultaneous emission of strongly alkaline fly ash restrained acidification processes. After 1989-1991 the situation changed, and in 1994-1996 the N deposition load in northeastern Estonia remained within the range of 2.6 to 6.6 kg ha(-1) year(-1) and that of S within 2 to 50 kg ha(-1) year(-1). Because the fly ash deposition is permanently decreasing, more sensitive lichens and mosses can be subjected to critical N+S loads in the future. The proportion of oil shale industry in total emission of NOx in Estonia from stationary sources equals approximately 65 to 75%. During 1996-2000 the yearly mean concentration of NO2 in the air of towns increased from 9 to 12 to 16 to 29 g m(-3). The emission of N compounds was mainly caused by N oxides in flue gases from power plants, as well as ammonia and carbamide discharges from chemical plants. In 1988-1990 the estimated yearly total emission of NOx (as NO2 equivalent) was about 18 to 18.6 thousand t and in 1994-2000, 9.9 to 11.8 thousand t.

Clinical and morphological aspects of death due to liquid nitrogen.

A 24-year-old student died while filling flasks with liquid nitrogen. The arms, legs and back were frozen and the face, ears and neck showed a dark red and livid colour with horizontal lines of demarcation. In the electrocardiogram, the heart showed asystolia followed by wide ventricular complexes. The patient was intubated orally as the situs of the larynx and pharynx showed no pathology findings. Cardiopulmonary resuscitation was carried out and terminated after 90 min. Unfortunately, the body temperature was not measured. The gas analysis of venous blood showed metabolic acidosis and oxygen deficiency. The student had worked alone with nitrogen, without opening the windows and without a working ventilation system. While filling the third flask he lost consciousness. As nitrogen does not cause characteristic prodromal signs he laid on the floor and was unable to help himself. The liquid nitrogen which was still escaping spread over the floor and vaporized. The student died from asphyxia due to oxygen deficiency in an atmosphere of nitrogen.

Maternal exposure to exogenous nitrogen compounds and complications of pregnancy.

Increased lipid peroxidation and reduced antioxidant activity have been reported with pregnancy complications. Given that exogenous oxidants stimulate formation of lipid peroxides, the authors investigated the relationship between exposure to nitrogen-oxidizing species and pregnancy complications and took into account markers of antioxidant and oxidant status. The study sample included pregnant women who were from an area polluted by oxidized nitrogen compounds. Methemoglobin, a biomarker of individual exposure, was determined, as were measures of oxidant/antioxidant status, including glutathione balance and lipid peroxide levels. Only 10 women experienced normal pregnancies. The most common complications were anemia (67%), threatened abortion/premature labor (33%), and signs of preeclampsia (23%). Methemoglobin was elevated significantly in all three conditions, compared with normal pregnancies. Reduced:total glutathione decreased, whereas lipid peroxide levels increased. These results suggest that maternal exposure to environmental oxidants can increase the risk of pregnancy complications through stimulation of the formation of cell-damaging lipid peroxides and from a decrease in maternal antioxidant reserves.