Little is known about how pharmacological and toxicological knowledge evolves. The aim of this study was to investigate the changes in the presentation of the poison hydrogen cyanide in sixteen German-language pharmacology and toxicology textbooks from 1878 to 2020. The categories of structure, molecular mechanism of action, occurrence, effects, resorption, areas of application, lethal dose, acute symptoms of intoxication, treatment of hydrogen cyanide poisoning, and recommended therapeutic preparations were evaluated. The knowledge on the structure, lethal dosage, and occurrence of hydrogen cyanide has remained constant. In contrast, knowledge on molecular mechanism of action and recommended preparations of the poison has changed dramatically. Until 1944, the binding of hydrogen cyanide to hemoglobin was considered the mechanism of action, whereas from 1951 onwards, the interaction of hydrogen cyanide with the Fe3+ of cytochrome oxidase was described. The number of preparations containing hydrogen cyanide decreased into obsolescence until 1951. The areas of application of hydrogen cyanide also show a change, as from 1919 onwards, mainly industrial areas of application of the poison are described instead of medical ones, and from 1951 onwards, criminalistic areas of application are also mentioned. Thus, pharmacological and toxicological knowledge develops non-linearly, molecular mechanism and uses being the most dynamic areas, whereas the knowledge about hydrogen cyanide\'s chemical structure, lethal dose, and occurrence remained constant. Older pharmacology and toxicology textbooks were better than newer ones at discussing changes in scientific concepts. Pharmacology and toxicology textbooks also mostly failed to discuss the misuse of hydrogen cyanide (Zyklon B) during the Nazi regime, missing an important opportunity to showcase the ethical responsibility of pharmacology and toxicology. Thus, future pharmacology and toxicology textbooks should improve on discussing the development of pharmacological and toxicological concepts and the ethical responsibility of the discipline.

The high phenotypic plasticity developed by plants includes rapid responses and adaptations to aggressive or changing environments. To achieve this, they evolved extremely efficient mechanisms of signaling mediated by a wide range of molecules, including small signal molecules. Among them, hydrogen cyanide (HCN) has been largely ignored due to its toxic characteristics. However, not only is it present in living organisms, but it has been shown that it serves several functions in all kingdoms of life. Research using model plants has changed the traditional point of view, and it has been demonstrated that HCN plays a positive role in the plant response to pathogens independently of its toxicity. Indeed, HCN induces a response aimed at protecting the plant from pathogen attack, and the HCN is provided either exogenously (in vitro or by some cyanogenic bacteria species present in the rhizosphere) or endogenously (in reactions involving ethylene, camalexin, or other cyanide-containing compounds). The contribution of different mechanisms to HCN function, including a new post-translational modification of cysteines in proteins, namely S-cyanylation, is discussed here. This work opens up an expanding \'HCN field\' of research related to plants and other organisms.

Carbon monoxide (CO) and hydrogen cyanide (HCN) are two common toxic products of combustion. HCN concentrations of fire victims are not routinely determined in most legal medicine services in Romania. We present the case of a room fire victim in which we evaluated the concentrations of HCN and carboxyhemoglobin (COHb), their contribution to the mechanism of death, and the possibility that HCN concentration can be interpreted as vital sign. COHb was determined by spectrophotometry. HCN was spectrophotometrically determined with ninhydrin in postmortem blood samples after its removal with 20% phosphoric acid and uptake into a solution of potassium carbonate. The presence of ethyl alcohol was determined by gas chromatography. The COHb concentration was 6.15%, while the blood HCN concentration was 1.043 µg × mL-1 and the total HCN was 1.904 µg × ml-1. A blood alcohol content of 4.36 g‰ and a urine alcohol content of 5.88 g‰ were also found. Although the fire produced a considerable amount of soot, and there were signs of inhalation of soot particles, the COHb level cannot be interpreted as a vital sign. Toxic concentrations of HCN and total HCN can be interpreted as a vital sign and indicates a contributive effect of HCN in the mechanism of death.

Cyanide toxicity is common after significant smoke inhalation. Two cases are presented that provide framework for the discussion of epidemiology, pathogenesis, presenting signs and symptoms, and treatment options of inhalational cyanide poisoning. An evidence-based algorithm is proposed that utilizes point-of-care testing to help physicians identify patients who benefit most from antidotal therapy.

A 32-year-old man attempted to poison his ex-girlfriend with hydrogen cyanide by hiding the pesticide Uragan D2 in her car. During the police investigation, chemical analysis of the air inside the car was performed. Hydrogen cyanide was detected through on-site air analysis using a portable Fourier transform infrared (FTIR) spectroscopy gas analyzer and colorimetric gas detection tubes. Furthermore, impinger air-sampling was performed for off-site sample preparation and analysis by gas chromatography-mass spectrometry (GC-MS). All three independent techniques demonstrated the presence of hydrogen cyanide, at concentrations of 14-20 ppm. Owing to the high volatility of hydrogen cyanide, the temperature and the time since exposure have a substantial effect on the likelihood of detecting hydrogen cyanide at a crime scene. The prevailing conditions (closed space, low temperature) must have supported the preservation of HCN in the car thus enabling the identification even though the analysis was performed several days after the hydrogen cyanide source was removed. This paper demonstrates the applicability of combining on-site FTIR measurements and off-site GC-MS analysis of a crime scene in order to ensure fast detection as well as unambiguous identification for forensic purposes of hydrogen cyanide in air.

For smoke inhalation injury of a pregnant woman, one must treat two patients and be aware of the potential effects of carbon monoxide (CO) and cyanide (CN) poisoning on both the mother and the fetus. In a pregnant woman, the size and age of the fetus and the degree of poisoning allow for tremendous variability in the toxicity of CO and CN and their respective treatment options. The authors will review a case of a 32-year-old woman who was at 37 weeks of gestation and admitted to the Evans-Haynes Burn Center after a house fire and received hydroxocobalamin (Cyanokit) for suspected CN poisoning. In addition, a review of the literature, current guidelines, and treatment options of inhalation injury during pregnancy will be discussed. The authors will focus only on the toxic components of smoke inhalation injury rather than the mechanical components from heat and particulate damage. Literature review clearly identifies that the treatment of pregnant women with inhalation injury remains a controversial subject. The use of hydroxocobalamin (Cyanokit) as a treatment modality for potential CN poisoning in a pregnant patient has not been reported in the literature. Animal studies have shown that combined CO and CN poisoning are more lethal than either one alone and at lower concentrations. Due to the synergistic effects of CO and CN, and because these two toxins concentrate at even higher levels in the fetus than the mother, the authors will clarify the urgent seriousness of prompt administration of hydroxocobalamin in a pregnant patient with suspected smoke inhalation injury. This case review details the treatment of a 32-year-old woman who was at 36 weeks of gestation on admission to the Evans-Haynes Burn Center. The authors will report her injuries and the course of treatment. Although burned and presenting with concomitant smoke inhalation injury, both the woman and her child fared well with no significant complications due to the smoke inhalation at 6 months of follow-up. Smoke inhaled from modern structural fires potentially contains both CN and CO gases. This makes the prompt recognition of this injury and selection of appropriate therapy an emergent priority. In October 2010, the Food and Drug Administration approved hydroxocobalamin for use in pregnant patients in the acute setting when CN toxicity is suspected. Because CO and CN have additive effects when both are present in the body, the prompt administration of hydroxocobalamin not only eliminates the effects of CN but also potentially attenuates its synergistic effects on CO. It is only through a better understanding of the details of smoke inhalation injury, the current treatment options, and the considerations regarding their use that new research and strong guidelines can be developed to better serve our patients.

Cyanide poisoning is an important source of morbidity and mortality from smoke exposure in structural fires. This case involved administration of a cyanide antidote to a prisoner (male, 23 years) in France, discovered in cardiorespiratory arrest after about 30 minutes exposure to smoke from a burning mattress during an apparent suicide attempt. Smoke exposure, circulatory failure during initial resuscitation, and elevated blood cyanide and lactate led to the diagnosis of cyanide poisoning. Hydroxocobalamin (Cyanokit®), 5 g intravenous) was given immediately and on arrival at the hospital. Cardiopulmonary resuscitation restored cardiovascular function after 33 minutes. There were no neurological or other sequelae. Timely hydroxocobalamin administration contributed to full recovery from cardiorespiratory arrest secondary to cyanide poisoning from smoke inhalation. Hydroxocobalamin should be available to emergency medical teams attending fire scenes.

An uncommon suicide by oral ingestion of potassium cyanide salts and contemporaneous inhalation of hydrogen cyanide is presented. A 48-year-old tradesman was found dead sitting in his car. A penetrating odor of bitter almonds was noticed when opening the doors. A camping stove and a cooking pot containing large amounts of dark blue crystals were found in the footwell of the car. White powder adhered to his fingers and to the area around the mouth. Furthermore bottles containing potassium ferrocyanide and different kinds of acid and leach were found in the car together with internet information about, e.g. potassium ferrocyanide and potassium cyanide. At autopsy hemorrhages and erosions of the mucosa of the respiratory tract, esophagus and stomach were found. Concentrations of cyanide were 0.2mg/l in stomach contents, 0.96mg/kg in brain tissue, 2.79mg/kg in lungs, and 5.3mg/l in blood. The white and toxic powder potassium cyanide was formed by heating of the yellow crystals of potassium ferrocyanide on the camping stove. This powder was probably ingested orally. Addition of acid converted the salt into the highly toxic gas hydrogen cyanide. Oxidation with atmospheric oxygen built the dark blue ferrous compound Prussian blue. This case report of a person who was not familiar with chemicals demonstrates the acquisition of professional information via the internet, enabling a suicide with a complex procedure.

Environmental monitoring of biological wastewater treatment plants (BWWTP) treating industrial effluents produces large amount of data. Frequent sampling is done in the influent and effluent but also in intermediate points. Samples are analyzed for classical and specific contaminants and physical-chemical parameters are monitored. In this paper data from a BWWTP treating the effluents of a coke and steel-processing factory are analyzed. Due to a complex situation, this BWWTP gave poor performances that did not match environmental regulations, meanwhile upgrading proved to be uneasy. Data analysis using principal component analyses (PCA) or kinetic modeling with a Haldane model was unsuccessful in handling these data, which was attributed to undetermined toxic effects. A new methodology is reported, that allowed to identify a kinetics for thiocyanate degradation and a relation between pH and toxic effects. This analysis of the plant data allowed to make hypothesis on the process control parameters and to recommend management modifications, allowing a further increase of the performances.

The purpose of this study was to report severe keloids caused by hydrogen cyanide injury. Hydrogen cyanide poisoning is still a problem as an occupational disease in China. We report a 37-year-old man with severe hydrogen cyanide poisoning. The patient fell on the floor after inhalation of hydrogen cyanide and was burned on his back by hydrocyanic acid. Sequential treatment included amyl nitrite by inhalation, intravenous sodium nitrite 3%, and intravenous sodium thiosulfate 25%. Other treatment consisted of incision of the trachea, mannitol and furosemide, antibiotics, and nutrient support measures. The patient also received hyperbaric oxygen therapy; during the first treatment, he became apneic and cardiopulmonary resuscitation was supplied in the hyperbaric oxygen chamber. He eventually recovered, but a large amount of keloids developed on his back and buttocks.