An introduction to the clinical toxicology of volatile substances

Butane-related deaths in post-mortem investigations: A systematic review

Volatile substance abuse is widespread among adolescents due to its easy availability and methods of consumption. Inhalant abuse represents a current problematic issue, causing significant morbidity and mortality due to direct toxicity on several target organs and displacement of gas which results in a lack of oxygen. This review aims to evaluate post-mortem and toxicological investigations in cases of suspected butane intoxication. We performed comprehensive research using the Preferred Reporting Items for Systematic Review (PRISMA) standards. Forty scientific papers fulfilled the inclusion criteria. A total of 58 cases of butane-related deaths were found. Among these, we found 11 cases of suicide (18%), 1 case of homicide (2%), 44 cases of accidental poisoning (76%), and 2 cases of work-related deaths (4%). Autopsy and post-mortem examinations were performed in 54 cases, whereas toxicological analyses were presented in 56 cases. In autopsy, pulmonary edema (51%) and poli-visceral congestion (59%) were the most common findings. When death by butane inhalation is hypothesized, autopsy and histological findings may be nonspecific, therefore toxicological investigations assume a crucial role along with attention to the methods used to collect biological samples.

Understanding the Mechanisms of Action and Effects of Drugs of Abuse

AIM

Drug abuse and addiction are major public health concerns, with millions of people worldwide affected by the negative consequences of drug use. To better understand this complex issue, a review was conducted to examine the mechanisms of action and effects of drugs of abuse, including their acute and chronic effects, the symptoms of abstinence syndrome, as well as their cardiovascular impacts.

METHODS

The analyzed data were obtained after surveying an electronic database, namely PubMed, with no time limit, grey literature sources, and reference lists of relevant articles.

RESULTS

The review highlights the different categories of drugs of abuse, such as opioids, stimulants, depressants, hallucinogens, and cannabis, and discusses the specific ways that each drug affects the brain and body. Additionally, the review explores the short-term and long-term effects of drug abuse on the body and mind, including changes in brain structure and function, physical health problems, and mental health issues, such as depression and anxiety. In addition, the review explores the effects of drug abuse on cardiovascular health, focusing on electrocardiogram changes. Moreover, the analysis of relevant literature also highlighted possible genetic susceptibility in various addictions. Furthermore, the review delves into the withdrawal symptoms that occur when someone stops using drugs of abuse after a period of chronic use.

CONCLUSION

Overall, this review provides a comprehensive overview of the current state of knowledge on drug abuse and addiction. The findings of this review can inform the development of evidence-based prevention and intervention strategies to address this critical public health issue.

A case report of recreational use of inhaled Freon leading to acute hypoxemic respiratory failure salvaged by veno-venous extracorporeal membrane oxygenation

BACKGROUND

Freon™ is a halogenated hydrocarbon often used as a refrigerant. When inhaled recreationally, it has the desired effects of euphoria and intoxication. Toxic effects include cardiovascular and neurologic insults such as arrhythmias and seizures, and less well-described toxicities include airway and lung injury. The treatment in general is primarily supportive.

CLINICAL FEATURES

We present the case of a 42-yr-old previously healthy male who developed acute bronchiolitis and pneumonitis following inhalation of Freon leading to severe respiratory failure. He was supported by veno-venous extracorporeal membrane oxygenation and managed with high-dose corticosteroids.

CONCLUSION

To our knowledge, this is the first case report of an inhaled Freon exposure resulting in acute lung injury refractory to conventional therapy that was salvaged by vv-ECMO as a bridge towards a full recovery.

Management of hydrocarbon burns: Considering mental health and biochemical abnormalities

Volatile substance misuse, particularly the inhalation of hydrocarbons, is a growing issue globally. Consequences of VSM, both acute or chronic, causes cardiovascular, respiratory, renal, metabolic and central nervous system damage. Whilst the effects of hydrocarbon abuse have been reported, the combination of intoxication with hydrocarbon and burns sustained has not yet been presented. A retrospective case series of patients who presented in the last 5 years to the Royal Adelaide Hospital with hydrocarbon-related burns in the context of illicit use was undertaken. Our aims are to present to the wider scientific community the high morbidity and mortality of hydrocarbon burn injuries and why this tertiary Burns Unit feel it most appropriate to medically stabilise these patients prior to definitive surgery for their burn. All patients that presented with acute hydrocarbon intoxication and sustained concomitant burns had significant psychiatric disorder and substance abuse history and three of five had either not eaten in several days resulting in acute malnourishment, refeeding syndrome or had evidence of chronic malnourishment with deranged electrolytes and hypoalbuminaemia. Their definitive burns surgery was delayed where appropriate in order to facilitate medical stabilisation as they were too high risk of cardiac membrane instability, electrolyte derangement and/or respiratory compromise to undergo safe general anaesthetic and burns debridement. We propose a multidisciplinary team approach, utilising not only our Burns Unit care model of physiotherapists, psychologists, social work and burns trained nurses and surgeons but also Intensive Care, Toxicology, Addiction medicine and General Medical physicians in the management of these patients.

Inhalants

Toxic inhalants include various xenobiotics. Irritants cause upper and lower respiratory tract injuries. Highly water-soluble agents injure the upper respiratory tract, while low water-soluble inhalants injure the lower track. Asphyxiants are divided into simple asphyxiants and chemical asphyxiants. Simple asphyxiants displace oxygen, causing hypoxia, while chemical asphyxiants also impair the body's ability to use oxygen. Cyanide is a classic chemical asphyxiant. Treatment includes hydroxocobalamin. Electronic cigarette or vaping use-associated lung injury (EVALI) is a relatively new illness. Patients present with respiratory symptoms and gastrointestinal distress. EVALI appears to be associated with vaping cannabinoids. Treatment is supportive and may include steroids.

Butane-induced acute global myocardial ischemia without coronary artery pathology

The case report describes a case of acute myocardial ischemia precipitated by propane butane inhalation. The dependency of this substance around the world is still moderate but is increasing due to the easy availability of the substance and the facility with which the effects can be concealed. The toxicity of the substance is significant; affecting the heart, the brain and the liver. The most common outcome is sudden death. In this article, we describe a survivor after an episode of acute poisoning and his interesting cardiac pathology.

N,N-dimethylglycine prevents toluene-induced impairment in recognition memory and synaptic plasticity in mice

Toluene intoxication produces deleterious effects on cognitive function, which has been associated with the inhibition of N-methyl-d-aspartate receptor (NMDAR). The present study determined whether N,N-dimethylglycine (DMG), a nutrient supplement and a partial agonist for NMDAR glycine binding site, could counteract recognition memory deficits and hippocampal synaptic dysfunction after acute toluene exposure. Male ICR mice were treated with toluene (250-750 mg/kg) for monitoring the sociability and social novelty in three-chamber test and long-term potentiation (LTP) of hippocampal synaptic transmission. Moreover, the combined effects of DMG (30-100 mg/kg) pretreatment with toluene (750 mg/kg) on three-chamber test, novel location and object recognition test and synaptic function were determined. Toluene decreased the sociability, preference for social novelty, hippocampal synaptic transmission and LTP in a dose-dependent manner. DMG pretreatment significantly reduced the toluene-induced memory impairment in social recognition, object location and object recognition and synaptic dysfunction. Furthermore, NMDAR glycine binding site antagonist, 7-chlorokynurenic acid, abolished the protective effects of DMG. These results indicate that DMG could prevent toluene-induced recognition memory deficits and synaptic dysfunction and its beneficial effects might be associated with modulation of NMDAR. These findings suggest that DMG supplementation might be an effective approach to prevent memory problems for the workers at risk of high-level toluene exposure or toluene abusers.

Airborne toluene exposure causes germline apoptosis and neuronal damage that promotes neurobehavioural changes in Caenorhabditis elegans

Toluene is a highly volatile organic solvent present in gasoline. Exposure mainly occurs by absorption via the pulmonary tract and easily reaches the central nervous system, which causes toxic effects. Toluene toxicity has been described but not well established. The present work aimed to evaluate the effects of airborne exposure to toluene, the in vivo model Caenorhabditis elegans was assessed to determine whether nematode could be used to evaluate the effects of exposure to toluene and the possible mechanisms of toxicity of the solvent. Worms at the first or fourth larval stages were exposed to toluene for 48 or 24 h, respectively, in a laboratory-developed vapor chamber at concentrations of 450, 850, 1250 and 1800 ppm. We observed increases in worm mortality and significant developmental delays that occurred in a concentration-dependent manner. An increased incidence of apoptotic events in treated germline cells was shown, which was consistent with observed reductions in reproductive capacity. In addition, toluene promoted significant behavioural changes affecting swimming movements and radial locomotion, which were associated with changes in the fluorescence intensity and morphology of GABAergic and cholinergic neurons. We conclude that toluene exposure was toxic to C. elegans, with effects produced by the induction of apoptosis and neuronal damage.

The pattern of substance abuse in Thai elderly: Ramathibodi Poison Center

Objective

To describe substances, clinical manifestations, treatment, and medical outcomes of substance abuse exposures among older adults in Thailand.

Method

This is a retrospective study of individuals aged 60 years or older with intentional abuse exposures reported to the Ramathibodi Poison Center from 1 January 2010 to 31 December 2017.

Results

Forty-four cases were reported. The most common manifestation was somnolence (20, 45.5%). The most common substance used was kratom. There were 12 severe and fatal cases. Only one died due to methadone abuse. The most frequent manifestation among severe cases was respiratory failure (8 of 12 cases, 66.7%). Two cases had severe metabolic acidosis and were treated with hemodialysis. Three cases received norepinephrine.

Conclusion

Substance abuse in the elderly is a serious problem that is often overlooked. Health personnel should promptly recognize and address this issue in order to reduce morbidity and mortality in the elderly population.

Antidotal effects of thymoquinone against neurotoxic agents

Several plants which contain the active component thymoquinone (TQ) have been traditionally used in herbal medicine to treat various diseases. Several studies indicated the protective effects of TQ against neurotoxic agents. The present study was aimed to highlight the protective effects of TQ against neurotoxic agents. For this reason, the literature from 1998 to 2017 regarding the protective effects of TQ against neurotoxic agents and their involvement mechanisms has been studied. The present review suggests the protective effects of TQ against neurotoxic agents in experimental models. More clinical trial studies are however needed to confirm the antidotal effects of TQ in human intoxication.

Effect of chronic toluene exposure on heart rhythm parameters

BACKGROUND

Toluene is used extensively in various industrial processes, and an increasing number of workers are getting exposed to its vapor. Cardiac abnormalities that have been reported in association with toluene exposure (in toxic doses) are atrioventricular conduction abnormalities, sinus bradycardia, ventricular tachycardia, recurrent myocardial infarction, dilated cardiomyopathy, and coronary vasospasm.

HYPOTHESIS

We aimed to investigate the effects of chronic toluene exposure on cardiac rhythm.

METHODS

In this study, 40 workers in the polishing industry with more than 3 months of exposure to a mixture of organic solvents including toluene and 38 control subjects working in other fields who were matched by age, sex, smoking, habits, and living accommodation were investigated. Twelve-lead surface electrocardiogram and 24-hour Holter recordings were performed to determine QRS duration, PR duration (P and R wave interval on electrocardiograms), P wave dispersion, corrected QT dispersion, and heart rate variability parameters.

RESULTS

The maximum heart rate was significantly lower in the toluene-exposed group compared to the control group (130.5 ± 15.1 vs 138.6 ± 16.0, P = 0.02). Corrected low frequency (cLF) and cLF/corrected high frequency (cHF) were also significantly lower in toluene-exposed group (43.6 ± 7.2 vs 50.7 ± 10.5, P = 0.01 and 1.4 ± 0.4 vs 2.2 ± 1.0, P < 0.01, respectively). Mean cHF, root-mean-square successive difference, and standard deviation of all five-minute NN interval means values were significantly higher in the toluene-exposed group (32.8 ± 8.1 vs 25.4 ± 8.2, P ≤ 0.01; 74.0 ± 46.1 vs 60.3 ± 59.4, P = 0.02; and 149.5 ± 77.0 vs 108.9 ± 43.2, P = 0.01, respectively).

CONCLUSIONS

This study implies that chronic toluene exposure disturbs cardiac autonomy, particularly by suppressing sympathetic activity, and parasympathetic suppression also occurs with increased exposure duration. We also demonstrated that chronic toluene exposure was not associated with major cardiac arrhythmias and rhythm conduction system disorders.

Fatal poisoning by butane sniffing: A forensic analysis and immunohistochemical detection of myocardial hypoxic damage

Although less widespread than twenty years ago, inhalant abuse remains an on-going problem, whose incidence among U.S. teenagers and young adults ranges from 10 to 15%. Death due to the inhalation of vapor from halogenated hydrocarbons is a well-known phenomenon, yet few cases of fatal butane-gas poisoning have been described. Many cases of volatile substance abuse in prison populations have been reported: drug-addicted inmates often resort to this alternative practice when unable to get their habitual drugs of abuse. A similar pattern occurs especially among adolescents. The study herein described was conducted including all cases of fatal acute intoxication of butane gas examined from 2007 to 2015 at the Institute of Legal Medicine and Forensic Sciences of the University of Genoa. In the absence of overt and specific macroscopic and histological findings indicating cause and pathological mechanism of death, we aimed to assess whether recent cardiac lesions were detectable by way of immunohistochemical (IHC) analysis. Specifically, fibronectin and troponin C expression in myocardial tissues were investigated in deaths from acute butane-gas poisoning so as to better define the underlying pathological mechanisms. IHC findings were indicative of hypoxic cardiac damage. In all cases, positivity to fibronectin and mildly to moderately reduced troponin C expression in cardiac muscle cells were immunohistochemically ascertained.

[The functional activity of lymphocytes in the spleen and peripheral blood in association with the toxic effect of household gas]

The objective of the present work was to study the population composition and functional activity of lymphocytes in the spleen and peripheral blood of the rats exposed experimentally to the toxic effect of household gas. The study included the morphofunctional examination of the state of the immune organs and the immunological investigation of the population composition and functional activity of lymphocytes from the peripheral blood of the experimental animals. We also evaluated the activity of nucleic acids, NADH2-dehydrogenase, and 5'-nucleotidase. The study revealed the relationship between the pathological and histochemical changes and the shifts in the population composition and functional activity of lymphocytes in the spleen and peripheral blood of the rats. Specifically, the action of household gas induced by the profound inhibition of the proliferative activity of the lymphocytes, enhanced the suppressive activity of the immunoregulatory cells (T-suppressors), and altered the population composition of the effector cells in the spleen and peripheral blood. It is concluded that the impairment of the functional activity of T-lymphocytes under the influence of household gas should be attributed not only to its direct toxic action but also to the increased activity of T-suppressors.

Is it worth carrying out determination of N-butane in postmortem samples? A case report and a comprehensive review of the literature

The aim of this article is to illustrate the importance of N-butane determination in postmortem samples through a case report and to propose actions and precautions to be taken into consideration when butane is suspected to be involved in cases of death. The case concerns a 15-year-old boy found dead after sniffing a cigarette lighter refill. Toxicological investigation revealed the presence of butane in the heart and femoral blood (1280 and 1170 μg/L, respectively), in the gastric contents (326 μg/L), and in the liver (1010 μg/kg) and lung tissues (210 μg/kg). Propane was present only in the blood samples at concentrations tenfolds lower.Butane can be involved in three kinds of fatalities: deliberate inhalations including volatile substance abuse (VSA), involuntary exposure, and homicides. A fatal outcome of butane inhalation can be caused by asphyxia and/or cardiac arrhythmia. In the context where butane exposure is evidenced by non-toxicological investigations, the usefulness of the determination of butane in postmortem samples is often questionable. However, it is admitted that butane-related deaths are generally underreported. Several difficulties including sample handling and storage, substantial variation in tissue concentrations, and lack of a lethal threshold make the interpretation of butane results challenging. In our opinion, systematic toxicological methods should be developed in order to analyze butane, at least when it concerns a typical VSA victim, even when butane is not actually suspected to be the cause of death.

Intensive care management following defibrillation of an adolescent girl after recreational inhalant use: a case report and review of the literature

We report the successful out-of-hospital defibrillation and intensive care management of a 14-year-old girl who developed ventricular fibrillation following the inhalation of two 150-mL butane cigarette lighter refill canisters. Following ambulance transport to the nearest tertiary pediatric health care facility, her acute clinical course consisted of sinus tachycardia, fluctuating consciousness, and severe cerebral agitation and combativeness. Over a period of 2 weeks, her neurological function significantly improved to the point she was able to be discharged back into the community, however, not without a number of formally identified neurological deficits. Inhalant gasses, through as yet unclear mechanisms, can cause the myocardium cell membrane to become unusually sensitive to catecholamines which in turn can sometimes lead to fatal arrhythmias. This case is reported for its rarity in terms of the patient being able to be discharged back into the community and to create awareness of the sudden and potentially devastating consequences of butane inhalant use for critical care physicians and prehospital health-care personnel.

Evidence of bioactivation of halomethanes and its relation to oxidative stress response in Chirostoma riojai, an endangered fish from a polluted lake in Mexico

Halomethanes (HMs) are produced autochthonously in water bodies through the action of ultraviolet light in the presence of HM precursors, such as dissolved organic carbon and halogens. In mammals, toxic effects induced by HMs are diverse and include oxidative stress, which is also induced by divalent and polyvalent metals; however, in fish little information is available on HM metabolism and its possible consequences at the population level. In the present study, high CYP 2E1 and GST theta-like activities were found in viscera of the Toluca silverside Chirostoma riojai from Lake Zumpango (LZ; central Mexico). Formaldehyde, one of the HM metabolites, was correlated with CYP 2E1 activity and also induced lipid peroxidation in viscera. Hepatic CYP 2E1 activity was correlated with GST theta-like activity, suggesting the coupling of both pathways of HM bioactivation and its consequent oxidative damage. Sediment metals, among others, were also responsible for oxidative stress, particularly iron, lead, arsenic and manganese. However, under normal environmental conditions, the antioxidant enzymes of this species sustain catalysis adapted to oxidative stress. Findings suggest that this fish species apparently has mechanisms of adaptation and recovery that enable it to confront toxic agents of natural origin, such as metals and other substances formed through natural processes, e.g., HMs. This has allowed C. riojai to colonize LZ despite the high sensitivity of this species to xenobiotics of anthropogenic origin.

GABAA-positive modulator selective discriminative stimulus effects of 1,1,1-trichloroethane vapor

BACKGROUND

The abuse-related behavioral effects of inhalant vapors are poorly understood but probably involve multiple neurotransmitter receptor mechanisms. The present study examined the receptor systems responsible for transducing the discriminative stimulus of the abused chlorinated hydrocarbon 1,1,1-trichloroethane (TCE) in mice.

METHODS

Thirty mice were trained to discriminate 10 min of 12,000 ppm TCE vapor exposure from air using an operant procedure. Substitution tests were then conduced with positive GABA(A) receptor modulators and/or NMDA receptor antagonists.

RESULTS

The nonselective benzodiazepines midazolam and diazepam produced 62% and 61% and the barbiturate pentobarbital produced 68% TCE-lever selection. Zaleplon, an alpha1 subunit-preferring positive GABA(A) receptor benzodiazepine-site positive modulator resulted in 29% TCE-lever selection. The direct extrasynaptic GABA(A) agonist gaboxodol (THIP) and the GABA reuptake inhibitor tiagabine failed to substitute for TCE. No substitution was elicited by a competitive (CGS-19755), noncompetitive (dizocilpine) or glycine-site (L701,324) NMDA antagonist. The mixed benzodiazepine/noncompetitive NMDA antagonist anesthetic Telazol and the anticonvulsant valproic acid exhibited low levels of partial substitution for TCE (38% and 39%, respectively). Ethanol and nitrous oxide failed to substitute for TCE.

CONCLUSIONS

The results suggest that the discriminative stimulus effects of TCE are fairly selectively mediated by positive modulation of GABA(A) receptors. The failure of gaboxadol to substitute and the poor substitution by zaleplon suggests that extrasynaptic GABA(A) receptors as well as GABA(A) receptors containing alpha1 subunits and are not involved in transducing the discriminative stimulus of TCE. Studies with additional GABA(A) benzodiazepine-site positive modulators will be necessary to confirm and extend these findings.

Protective effects of quercetine on the neuronal injury in frontal cortex after chronic toluene exposure

The aim of this study was designed to evaluate the possible protective effects of quercetine (QE) on the neuronal injury in the frontal cortex after chronic toluene exposure in rats. The rats were randomly allotted into one of the three experimental groups, namely, groups A (control), B (toluene treated) and C (toluene-treated with QE), where each group contains 10 animals. Control group received 1 ml of normal saline solution, and toluene treatment was performed by the inhalation of 3000 ppm toluene in an 8-h/day and 6-day/week order for 12 weeks. The rats in QE-treated group was given QE (15 mg/kg body weight) once a day intraperitoneally for 12 weeks, starting just after toluene exposure. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of neurodegeneration in the frontal cortex after chronic toluene exposure in rats by QE treatment have been reported. In this study, the morphology of neurons in the QE treatment group was well protected. Chronic toluene exposure caused severe degenerative changes, shrunken cytoplasm and extensively dark picnotic nuclei in neurons of the frontal cortex. We conclude that QE therapy causes morphologic improvement in neurodegeneration of frontal cortex after chronic toluene exposure in rats. We believe that further preclinical research into the utility of QE may indicate its usefulness as a potential treatment on neurodegeneration after chronic toluene exposure in rats.

Histopathological changes of rat kidney with exposure to chronic thinner inhalation

INTRODUCTION

Organic solvents are liquid substances commonly used in everyday life at home and in industrial workplaces. These solvents are found primarily in paint as thinner. Because other narcotics are hard to find, thinner is used as a narcotic especially among youngsters of low socioeconomic level. The aim of this study is to determine the histopathological changes of rat kidney with exposure to chronic thinner inhalation.

METHODS

Randomized trial--the study was conducted at the animal care facility of Haydarpasa Numune Education and Research Hospital. Forty albino Wistar male rats were used throughout the experiment. Three groups of rats inhaled thinner in a glass cage for 1, 3, and 5 weeks, respectively. Ten rats inhaled only the air in the room as the control group.

RESULTS

We observed the development of inflammation in the kidneys that became more remarkable as exposure time extended. Development of inflammation because of thinner apparently differed between the groups of week 1 and week 5. There was no difference in granuloma development. If the experiment lasted longer, there might have been granuloma development.

CONCLUSIONS

Based on histopathological evaluations, it was shown that exposure to chronic thinner inhalation causes detectable damage on the kidney, which becomes more prominent as exposure period extends. As we established disorders in movement and consciousness in the rats during thinner inhalation, we can conclude that thinner also has a damaging effect upon the central nervous system.

Neurologic aspects of drug abuse

Neurologic aspects of drug abuse vary. This article explains the general nature of drug abuse, identifies the physiologic effects of certain drugs, and briefly describes the neurobiology of addiction. This article also reviews available treatment options for those addicted to substances of abuse, and clarifies common misconceptions, including the differences between tolerance, abuse, and addiction.

Histopathological changes of rat larynx mucosa with exposure to chronic thinner inhalation

Objective: Histopathological changes in nasal mucosa, trachea, and pulmonary system with exposure to chronic thinner inhalation have been studied in the literature. However, the possible changes in larynx mucosa, which is a part of the upper airway tract, have not been studied yet. The aim of this study is to determine the histopathological changes of rat larynx mucosa with exposure to chronic thinner inhalation.

Study Design and Setting: Randomized trial. The study was conducted at the animal care facility of Haydarpasa Numune Education and Research Hospital.

Subjects and Methods: Fifty-one Sprague-Dawley rats were used throughout the experiment. Four groups of rats inhaled thinner in a glass cage for 2, 4, 8, and 12 weeks respectively. Seven rats inhaled only the air in the room as the control group.

Results: The comparison of inflammation and exocytosis in the control and 2 week groups revealed no significant difference ( P > 0.05), but from the beginning of 4 weeks of thinner inhalation, statistically significant differences were observed ( P < 0.05). From the beginning of 8 weeks of thinner inhalation, statistically significant differences were observed in larynx mucosa when we assessed metaplasia and cilia loss distribution among groups ( P < 0.05).

Conclusion: On the basis of histopathological evaluations, it was shown that the harmful effect of inhalation of thinner in high concentrations to larynx mucosa is similar to the effect on other organs of the respiratory system.

Chloroform deposition in renal cyst fluid of hemodialysis patients with renal cystic disorders

Chronic exposure to chloroform (CHCl3) induces renal neoplasms in rodents and may be carcinogenic in humans, but studies on chronic CHCl3 deposition in the human body have not been performed. In this study, we examined 27 hemodialysis patients with renal cystic diseases including acquired cystic disease of the kidney (ACDK) accompanied by renal tumors at high frequency. Intracystic and serum CHCl3 concentrations were determined using a headspace gas chromatography/mass spectrometry analysis. CHCl3 was not detected in the serum in any cases, but levels ranging from <0.1 to 0.659 mg/L were found in the cyst fluid in most cases, including patients with ACDK and autosomal dominant polycystic kidney disease. Because intracystic CHCl3 deposition was not confined to ACDK cases, we were unable to evaluate the relationship between CHCl3 accumulation and carcinogenesis in ACDK. However, our results suggest that compounds such as CHCl3 accumulate in renal cyst fluid in hemodialysis patients with renal cystic diseases.

Negatively-charged air conditions and responses of the human psycho-neuro-endocrino-immune network

BACKGROUND

Against increasing environmental adverse effects on human health such as those associated with water and ground pollution, as well as out- and indoor air conditions, trials were conducted to support and promote human health by improving the indoor air atmosphere. This study was performed to estimate the effect of negatively-charged air conditions on human biological markers related to the psycho-neuro-endocrino-immune (PNEI) network.

OBJECTIVES

After construction of negatively-charged experimental rooms (NCRs), healthy volunteers were admitted to these rooms and control rooms (CTRs) and various biological responses were analyzed.

METHODS

NCRs were constructed using a fine charcoal coating and applying an electric voltage (72 V) between the backside of walls and the ground. Various biological markers were monitored that related to general conditions, autonomic nervous systems, stress markers, immunological parameters and blood flow.

RESULTS

Regarding the indoor environment, only negatively-charged air resulted in the difference between the CTR and NCR groups. The well-controlled experimental model-room to examine the biological effects of negatively-charged air was therefore established. Among the various parameters, IL-2, IL-4, the mean RR interval of the heart rate, and blood viscosity differed significantly between the CTR and NCR groups. In addition, the following formula was used to detect NCR-biological responses: Biological Response Value (BRV)=0.498+0.0005 [salivary cortisol]+0.072 [IL-2]+0.003 [HRM-SD]-0.013 [blood viscosity]-0.009 [blood sugar]+0.017 [pulse rate].

CONCLUSIONS

Negatively-charged air conditions activated the immune system slightly, smoothened blood flow and stabilized the autonomic nervous system. Although this is the first report to analyze negatively-charged air conditions on human biological responses, the long-term effects should be analyzed for the general use of these artificial atmospheres.

Maternal and fetal blood and organ toluene levels in rats following acute and repeated binge inhalation exposure

Inhalation of organic solvents is a persistent form of drug abuse with particular concern being the abuse of inhalants by women of child-bearing age. While studies have begun assessing postnatal outcomes of offspring exposed prenatally to inhalants, relatively little is known about the distribution of toluene in blood and body tissues of pregnant, inhalant-abusing women, or in the fetuses. The present study assessed the tissue toluene levels attained following brief toluene exposures using a pre-clinical rat model of maternal inhalant abuse. Timed-pregnant Sprague-Dawley rats were exposed to toluene at 8000 or 12,000 parts per million (ppm) for 15, 30 or 45 min/exposure. Exposures occurred twice each day from gestational day 8 (GD8) through GD20. Immediately following the second exposure on GD8, GD14 and GD20 blood was taken from the saphenous vein of the dams. Following saphenous vein blood collection on GD20, dams were sacrificed and trunk blood was collected along with maternal tissue specimens from cerebellum, heart, lung, kidney and liver. The placenta, amniotic fluid and fetal brain were also collected. Results demonstrated that maternal saphenous blood toluene levels increased as the inhaled concentration of toluene and duration of exposure increased. The maternal cerebellum, heart, kidney and liver appeared to be saturated after 30 min on GD20 such that toluene levels in those organs were equivalent across all ambient concentrations of inhaled toluene. Toluene levels also increased in fetal brain as the inhaled concentration of toluene increased and in placenta and amniotic fluid as the duration of exposure increased. Toluene levels in all tissues at GD20, except maternal lung and amniotic fluid, were higher than in maternal saphenous blood suggesting that toluene concentrated in those organs. Measurement of toluene levels in blood and other tissues following repeated toluene exposure demonstrated that toluene readily reaches a variety of potential sites of action throughout the maternal-placental-fetal unit.

The effect of inhaling thinner and/or cigarette smoke on rat kidneys

Although the effects of cigarette smoking and/or thinner inhalation on various organs have been investigated, there isn't enough study available in literature about their effects on kidneys. Therefore, in this study we investigated the effect of smoking and/or inhalation on the rat kidney. In this study, stand-alone inhalation of thinner and cigarette smoke and their application together were used to determine histopathologic changes, primarily the influences on rat kidneys. The study included 60 Wistar Albino species male rats. The 60 rats were divided into 4 groups of 15 rats each. Of the groups, three were working groups and the fourth was the control group. The rats in the first study group inhaled thinner only (T), those in the second group cigarette smoke only (CS), and the rats in the third group were made to inhale both thinner and cigarette smoke (TC). Each study group was divided into 3 subgroups each comprising 5 rats and inhalation was continued for periods of 2 wk, 4 wk, and 6 wk. Thinner was vaporized into the cage with a millipore pump at a constant pressure twice per day for 1 h for 5 days (toluene 2800-3000 ppm, acetone 500-600 ppm, isobutyl acetate 7000-8000 ppm, and isobutanol 6000-7000 ppm). Cigarette smoke was given 4 times per day for 15 min each, using a mechanism prepared with an aquarium motor (containing 1.2 mg nicotine,13 mg tar, and 13 mg carbonmonoxide; 60 puffs/min). After that, rat kidneys were removed. The kidneys were weighed and were given macroscopic and microscopic examination. There were significant differences for the thinner and thinner + cigarette smoke groups in comparison to the control group, observed in both proximal and distal tubules. However, changes in the cigarette smoke group were only in proximal tubules and were smaller in extent. Thinner has been widely used as a industrial substance. Thinner usage is an important health problem. Those sniffing thinner generally also use cigarettes. The findings of the present study reemphasize the importance of taking immediate measures in order to prevent thinner inhaling among homeless children, who pose an important social problem, and to protect people who work in industrial branches that widely use thinner.

Dilated Cardiomyopathy Associated with Toluene Abuse

The use of paint thinner and glue to achieve an euphoric state has been associated with serious social and health problems in children and young adults. We present the case of a 21-year-old man with dilated cardiomyopathy occurring following abuse of paint thinner and glue containing toluene as main compound. After cessation of toluene abuse, the patient recovered rapidly and completely. Because of the increasing prevalence of toluene abuse, harmful effects of this volatile agent on the heart are also discussed.

Sudden death after isobutane sniffing: a report of two forensic cases

The intentional inhalation of a volatile substance ("sniffing") causing euphoria and hallucinations is an under-recognised form of substance abuse in children and adolescents with a high morbidity and mortality. Sudden death can be caused by cardiac arrhythmia, asphyxia or trauma. Two fatal cases of isobutane sniffing of cigarette lighter refill containing isobutane are reported. Toxicological investigations revealed the presence of isobutane in the heart blood and brain tissue of both cases (case 1: heart blood 0.1 microg/g, brain tissue 2.3 microg/g; case 2: heart blood 4.6 microg/g, brain tissue 17.4 microg/g) and the presence of its metabolite 2-methyl-2-propanol in the heart blood of both cases (0.5 and 1.8 microg/g, respectively). The histological investigations of the inner organs showed similar results in both victims. Autopsy findings, results of the histological and immunohistochemical investigations, toxicological findings and analytical procedures are discussed.

Behavioral effects of toluene in rats selectively bred for infantile vocalization rate

Glue sniffing is epidemic among children living in poverty in Latin America. Previous research has shown that abused inhalants such as toluene share pharmacological properties with anxiolytic drugs, and that personality factors such as degree of anxiety have been proposed to modulate the effects of these drugs. To study this interaction in an animal model, rats selectively bred for high (High) or low (Low) rates of distress calls after maternal separation (ultrasonic vocalizations, USVs) were used to investigate toluene's acute and long-term effects on two measures of anxiety behavior. At ten days of age, neonatal subjects were administered toluene (1 g/kg i.p.) and USVs were recorded. The subjects were retested as juveniles on an elevated plus maze to examine sequela of earlier toluene exposure. Acute toluene administration reduced USVs relative to control groups in neonates of both lines, indicating anxiolysis. As expected, Lows had reduced USVs relative to Highs. At 28 days of age, Highs spent more time in the open arms of the elevated plus maze than Lows. However, prior neonatal toluene exposure blocked this reversal of behavioral phenotype. This suggests that early toluene exposure compromised a compensatory process occurring during this developmental period, which may have been maternally mediated. These results have implications for the effects of early drug exposure on plasticity in the developing nervous system.

Synthesis and evaluation of inhaled [11C]butane and intravenously injected [11C]acetone as potential radiotracers for studying inhalant abuse

The phenomenon of inhalant abuse is a growing problem in the US and many countries around the world. Yet, relatively little is known about the pharmacokinetic properties of inhalants that underlie their abuse potential. While the synthesis of 11C-labeled toluene, acetone and butane has been proposed in the literature, none of these compounds has been developed as radiotracers for PET studies. In the present report we extend our previous studies with [11C]toluene to include [11C]acetone and [11C]butane with the goal of comparing the pharmacokinetic profiles of these three volatile abused substances. Both [11C]toluene and [11C]acetone were administered intravenously and [11C]butane was administered via inhalation to anesthesized baboons. Rapid and efficient uptake of radiolabeled toluene and acetone into the brain was followed by fast clearance in the case of toluene and slower kinetics in the case of acetone. [11C]Butane was detected in the blood and brain following inhalation, but the levels of radioactivity in both tissues dropped to half of the maximal values over the period of less than a minute. To our knowledge, this is the first reported study of the in vivo brain pharmacokinetics of labeled acetone and butane in nonhuman primates. These data provide insight into the pharmacokinetic features possibly associated with the abuse liability of toluene, acetone and butane.

Reduction of post-shift traffic injuries among gasoline station workers: Are they related to the reduction of occupational gasoline vapor exposure?

AIMS

Solvents exposure is known to impair psychomotor performances. With gasoline vapor recovery devices (GVRD) installed, this study should observe a decrease of traffic injuries after shift among gasoline workers.

METHODS

The occupational injury registry data of 1991-2000 in a petrochemical company containing 20,000 workers were analyzed. Cumulative injury rate (CIR) was calculated to estimate lifetime risk. The potential workday loss (PWDL) and the potential salary loss (PSL), which summed up the expected workdays and salary loss assuming a uniform retirement age of 65, were calculated for traffic injuries. Workers of gasoline sales were compared with those without gasoline exposure for commuting traffic injuries. The rate ratio (RR) was calculated based on a person-time data.

RESULTS

The CIR dropped 3.14 times during 1997-2000 for commuting accidents on the way back home compared with that during 1991-1992, and the PWDL and PSL dropped 25.2 and 21.5 times, respectively, which corresponded with the time of installments of GVRD. The RRs of commuting accidents on the way back home in the exposed group significantly decreased from 2.15 to 0.53.

CONCLUSIONS

The decrease of commuting injuries on journey back home for gasoline workers were probably related to the effective reduction of solvent exposure.

Immunohistochemical localization of toluene-induced c-Fos protein expression in the rat brain

Although toluene is a widely abused substance, the neuronal populations and pathways mediating its effects are not well understood. Using c-Fos protein as a marker for neuronal activation, the present study investigated the pattern of c-Fos induction at 1h after various doses (0, 300, 750, and 1000 mg/kg, i.p.) of toluene injection in adult male rats. Quantitative analysis of Fos-immunoreactive neurons indicated toluene dose-related induced c-Fos immunoreactivity in the majority of structures examined. The structures included several cortex subareas (primary motor cortex, secondary motor cortex, somatosensory cortex, frontal association cortex, cigulate cortex area 1, cigulate cortex area 2, prelimbic cortex, infralimbic cortex, retrosplenial agranular cortex, ventral orbital cortex, lateral orbital cortex, and piriform cortex), ventral tegmental area, nucleus accumbens shell, thalamic nuclei (mediodorsal, lateral posterior, and laterodorsal ventrolateral) and pontine nuclei. However, the substantia nigra, caudate putamen, nucleus accumbens core, subthalamic nucleus, hippocampus and cerebellum were almost unaffected. The data demonstrate that toluene dose-related induced a unique pattern of c-Fos immunoreactivity. The widespread distribution of toluene-induced c-Fos expression seen in this study can be linked to the profound alterations in physiological function and behavior produced by this solvent.

Abuse pattern of gestational toluene exposure and early postnatal development in rats

Inhalant abuse in the United States trails only alcohol, marijuana and nicotine abuse. Toluene, found in glues and cleaners, is among the most commonly abused inhalants. While teratogenicity due to occupational exposure to organic solvents (i.e., relatively long-term exposure to lower concentrations) has been studied, the teratogenic potential of organic solvent abuse (i.e., brief inhalation exposures to very high concentrations) has not been thoroughly examined. In a preclinical model of abuse patterns of fetal solvent exposure, timed-pregnant rats were exposed to 8000 parts per million (ppm) or 12,000 ppm of toluene, or to air (0 ppm), for 15 min twice daily from gestation day 8 (GD8) through GD20. After parturition, pups were tested from postnatal day 4 (PN4) to PN21 in a developmental test battery including measures of growth (i.e., body weight), maturational milestones (i.e., pinnae unfolding, incisor eruption and eye opening) and biobehavioral development (e.g., negative geotaxis, surface righting and grip strength). Pups exposed in utero to 12,000 ppm toluene weighed significantly less than the control pups at all ages before PN16. There were significant toluene-induced increases in an index of poor perinatal outcome (i.e., a combination of malformations, "runting" and neonatal death) and deficits in negative geotaxis. There were no significant delays in reaching maturational milestones. The results demonstrate that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth restriction, malformation and impairments of biobehavioral development in rats. A comparison of the present outcomes to previous studies of occupational exposure patterns suggests that for a given daily "dose" of toluene, a binge pattern of exposure may pose a greater risk for fetal development. Since the pattern of exposure in this experiment models binge exposure in human solvent abuse, the results imply that abuse of inhaled organic solvents, such as toluene, can cause similar teratogenic outcomes in humans.

Involvement of NO/cGMP pathway in toluene-induced locomotor hyperactivity in female rats

RATIONALE

Nitric oxide (NO) is implicated in the acute locomotor activating effects of some addictive drugs such as amphetamine, caffeine, and PCP, but has not been investigated in the case of toluene.

OBJECTIVES

This study determined the contribution of the NO-cyclic GMP (cGMP) pathway to locomotor stimulant effects of toluene.

METHODS

Locomotor activity was measured for 90 min immediately following toluene (500-1,000 mg/kg, IP) or corn oil treatments in Sprague-Dawley female rats. A NO generator, sodium nitroprusside (SNP) (3 and 6 mg/kg), a NO precursor, L-arginine ( L-Arg) (250 mg/kg), a NO synthase inhibitor, N(G)-nitro- L-arginine methyl ester (L-NAME) (5-20 mg/kg, IP), and a soluble guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 mg/kg) were injected 5 min before toluene (750 mg/kg, IP) treatment. The combination effects of SNP with L-NAME, L-arginine with L-NAME, SNP with ODQ and L-arginine with ODQ on toluene-induced locomotor hyperactivity were also determined. RESULTS. The locomotor hyperactivity induced by toluene was significantly inhibited by SNP and L-arginine, but enhanced by L-NAME and ODQ. SNP and L-arginine completely reversed the combined effects of L-NAME and toluene to a basal level and abolished the enhancing effects of ODQ.

CONCLUSIONS

The results suggested that NO/cGMP-dependent mechanism might be involved in toluene-induced locomotor activity in rats.