Toxicological aspects of increased use of surface and hand disinfectants in Croatia during the COVID-19 pandemic: a preliminary report.

All COVID-19 prevention strategies include regular use of surface disinfectants and hand sanitisers. As these measures took hold in Croatia, the Croatian Poison Control Centre started receiving phone calls from the general public and healthcare workers, which prompted us to investigate whether the risk of suspected/symptomatic poisonings with disinfectants and sanitisers really increased. To that end we compared their frequency and characteristics in the first half of 2019 and 2020. Cases of exposures to disinfectants doubled in the first half of 2020 (41 vs 21 cases in 2019), and exposure to sanitisers increased about nine times (46 vs 5 cases in 2019). In 2020, the most common ingredients of disinfectants and sanitisers involved in poisoning incidents were hypochlorite/glutaraldehyde, and ethanol/isopropyl alcohol, respectively. Exposures to disinfectants were recorded mostly in adults (56 %) as accidental (78 %) through ingestion or inhalation (86 %). Fortunately, most callers were asymptomatic (people called for advice because they were concerned), but nearly half reported mild gastrointestinal or respiratory irritation, and in one case severe symptoms were reported (gastrointestinal corrosive injury). Reports of exposure to hand sanitisers highlighted preschool children as the most vulnerable group. Accidental exposure through ingestion dominated, but, again, only mild symptoms (gastrointestinal or eye irritation) developed in one third of the cases. These preliminary findings, however limited, confirm that increased availability and use of disinfectants and sanitisers significantly increased the risk of poisoning, particularly in preschool children through accidental ingestion of hand sanitisers. We therefore believe that epidemiological recommendations for COVID-19 prevention should include warnings informing the general public of the risks of poisoning with surface and hand disinfectants in particular.

Increasing tolerance of hospital Enterococcus faecium to handwash alcohols.

Alcohol-based disinfectants and particularly hand rubs are a key way to control hospital infections worldwide. Such disinfectants restrict transmission of pathogens, such as multidrug-resistant Staphylococcus aureus and Enterococcus faecium Despite this success, health care infections caused by E. faecium are increasing. We tested alcohol tolerance of 139 hospital isolates of E. faecium obtained between 1997 and 2015 and found that E. faecium isolates after 2010 were 10-fold more tolerant to killing by alcohol than were older isolates. Using a mouse gut colonization model of E. faecium transmission, we showed that alcohol-tolerant E. faecium resisted standard 70% isopropanol surface disinfection, resulting in greater mouse gut colonization compared to alcohol-sensitive E. faecium We next looked for bacterial genomic signatures of adaptation. Alcohol-tolerant E. faecium accumulated mutations in genes involved in carbohydrate uptake and metabolism. Mutagenesis confirmed the roles of these genes in the tolerance of E. faecium to isopropanol. These findings suggest that bacterial adaptation is complicating infection control recommendations, necessitating additional procedures to prevent E. faecium from spreading in hospital settings.

Expansion of the applicability domain for highly volatile substances on the Short Time Exposure test method and the predictive performance in assessing eye irritation potential.

The Short Time Exposure (STE) test method is an in vitro method for assessing the eye irritation potential of chemicals and is used to classify the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Category 1 and No Category (NC). The method has been adopted by the Organisation for Economic Co-operation and Development (OECD) as test guideline (TG) 491 since 2015. While this method can be used to classify GHS NC, it is not suitable for testing highly volatile substances and solids other than surfactants. Here we evaluated highly volatile substances to expand the applicability domain. According to TG 491, acetone, ethanol, iso-propanol, and methyl acetate as highly volatile substances resulted in false negatives. Saline was selected as a solvent of these false negatives. In this study, mineral oil was used as the solvent, because these false negatives were amphiphilic. Based on this change, four highly volatile substances were correctly evaluated. The predictive performance for classifying GHS NC was then verified using a substance dataset constructed in reference to the Draize eye test Reference Database and STE Summary Review Document. The accuracy and false-negative rate were 86.6% (194/224) and 3.8% (3/80), respectively. Collectively, the applicability domain was expanded by changing the solvent to mineral oil for highly volatile substances, and the predictive performance for the new applicability domain including highly volatile substances was excellent. The STE test method is suitable to classify GHS NC, indicating its applicability as a test method in a bottom-up approach.

DNA damage levels in electronics workers in Southern China: A micro-whole blood comet assay.

We evaluated DNA damage levels of different categories of workers exposed to hazards inside electronics factories in Southern China. To find out the most dangerous risk factor, a cross-sectional study was conducted on a total of 584 exposed subjects and 138 controls in an electronics factory in Southern China, where the electronics industry is prevalent. The exposed hazards included isopropanol (IPO), lead, noise, video display terminals (VDT), lead in a high-temperature (high-temp) environment, and IPO in a high-temp environment. DNA damage detection was performed by the micro-whole blood comet assay using peripheral blood. DNA damage levels were estimated by percent tail DNA (%T). Linear regression models were used to test DNA damage differences between exposed groups and control group with adjustments for potential confounding factors. The level of DNA damage was more significant in both lead in a high-temp and IPO in a high-temp environment groups than in that of the controls (p<0.05). The differences remained significant after stratifying by smoking status (p<0.05). There were no significant differences between groups exposed to IPO, lead, noise, VDT environment and controls. In conclusion, we identified potential risk factors for DNA damage to electronics workers. Special attention should be paid to workers exposed to IPO and lead in a high-temp environment.

Identifying novel genes and chemicals related to nasopharyngeal cancer in a heterogeneous network.

Nasopharyngeal cancer or nasopharyngeal carcinoma (NPC) is the most common cancer originating in the nasopharynx. The factors that induce nasopharyngeal cancer are still not clear. Additional information about the chemicals or genes related to nasopharyngeal cancer will promote a better understanding of the pathogenesis of this cancer and the factors that induce it. Thus, a computational method NPC-RGCP was proposed in this study to identify the possible relevant chemicals and genes based on the presently known chemicals and genes related to nasopharyngeal cancer. To extensively utilize the functional associations between proteins and chemicals, a heterogeneous network was constructed based on interactions of proteins and chemicals. The NPC-RGCP included two stages: the searching stage and the screening stage. The former stage is for finding new possible genes and chemicals in the heterogeneous network, while the latter stage is for screening and removing false discoveries and selecting the core genes and chemicals. As a result, five putative genes, CXCR3, IRF1, CDK1, GSTP1, and CDH2, and seven putative chemicals, iron, propionic acid, dimethyl sulfoxide, isopropanol, erythrose 4-phosphate, ß-D-Fructose 6-phosphate, and flavin adenine dinucleotide, were identified by NPC-RGCP. Extensive analyses provided confirmation that the putative genes and chemicals have significant associations with nasopharyngeal cancer.

Astragaloside IV attenuates apoptosis of hypertrophic cardiomyocyte through inhibiting oxidative stress and calpain-1 activation.

Calpain-1 activation and oxidative stress are two critical factors contributing to apoptosis of hypertrophic cardiomyocyte. Astragaloside IV (ASIV) exhibits protective effect against various heart diseases. The present study was designed to investigate whether the inhibitory effect of ASIV on isoproterenol (ISO)-induced apoptosis of hypertrophic cardiomyocyte was associated with the anti-oxidation and calpain-1 inhibition. Hypertrophy, apoptosis, mitochondrial oxidative stress and calpain-1 expression were measured in the heart tissue of Sprague-Dawley (SD) rats and H9C2 cells treated with ISO alone or combination with ASIV. The results showed that ASIV attenuated apoptotic rate, increased Bcl-2 expression, decreased Bax expression, ameliorated the integrity of mitochondrial structure and improved mitochondrial membrane potential (MMP). Moreover, ASIV combination reduced both calpain-1 protein expression and calpain activity, down-regulated mitochondrial NOX4 (mito-NOX4) expression, increased activity of mitochondrial superoxide dismutase (mito-SOD) and mitochondrial catalase (mito-CAT) compared to ISO treated alone. The results suggested that ASIV exerted anti-apoptosis effect on ISO-induced hypertrophic cardiomyocyte by attenuating oxidative stress and calpain-1 activation.

Using isopropyl alcohol impregnated disinfection caps in the neonatal intensive care unit can cause isopropyl alcohol toxicity.

AIM: The safety of SwabCap alcohol impregnated disinfection caps was questioned in our unit because of malfunctions in luer access valves. We examined whether SwabCaps affected the integrity of two luer access valves and were associated with alcohol injected into the lines. METHODS: Our bench test study included seven circuits using SmartSite or CARESITE valves exposed to two environmental temperatures. Passive circuits consisted of a 96-hour contact system using SwabCap without other interventions. Active circuits consisted of nine sham injections during a 24-hour period, with the SwabCap replaced after each injection. The active control circuit used isopropyl alcohol impregnated pads to disinfect valves. Isopropyl alcohol was measured at the extremity of all active circuits by gas chromatography. RESULTS: The visual appearance of all SmartSite valves and 67% of the CARESITE valves was changed by SwabCap use. The mean isopropyl alcohol dosages were 52 mmol/L in the SmartSite and 8 mmol/L in the CARESITE at room temperature and 73 and 7 mmol/L, respectively, at 35°C. No alcohol was found in the control circuit. CONCLUSION: The SwabCap altered the valves' appearance and allowed significant amounts of isopropyl alcohol to be injected. It should not be used for neonates without further research.

Etanol e isopropanol: genotoxicidad y teratogénesis evaluada aplicando el modelo de Drosophila melanogaster / Ethanol and isopropanol: genotoxicity and teratogenicity evaluated using Drosophila melanogaster as a model system

El etanol y el isopropanol son, de los alcoholes alifáticos de cadena corta, los más frecuentemente asociados a la actividad humana tanto a nivel industrial como en el entorno doméstico. En este trabajo se presentan los principales hallazgos reportados en la literatura para ensayos de genotoxicidad y teratogénesis en modelos experimentales de distinto nivel de complejidad, con especial énfasis en Drosophila melanogaster. El metabolismo de estos alcoholes es semejante en Drosophila y en humanos por lo cual la mosca es un buen modelo in vivo para la evaluación de sus potenciales efectos tóxicos, genotóxicos y teratogénicos.

Ethanol and isopropanol are two of the short chain aliphatic alcohols more frequently associated to the human environment, both in the industrial and domestic conditions. The aim of this work was to present the main findings reported in the literature about their genotoxicity and teratogenicity in experimental models of different level of complexity, with special emphasis in Drosophila melanogaster. Taking into account that the metabolism of both alcohols in Drosophila and humans is similar, the fly is a good model for the evaluation of their potentially toxic, genotoxic and teratogenic effects.

Pulmonary toxicity of perfluorinated silane-based nanofilm spray products: solvent dependency.

A number of cases of pulmonary injury by use of aerosolized surface coating products have been reported worldwide. The aerosol from a commercial alcohol-based nanofilm product (NFP) for coating of nonabsorbing surfaces was found to induce severe lung damage in a recent mouse bioassay. The NFP contained a 1H,1H,2H,2H-perfluorooctyl trialkoxysilane (POTS) and the effects were associated with the hydrolyzed forms of the silane; increase in hydrolyzation resulted in faster induction of compromised breathing and induction of lung damage. In this study, the impact of the solvent on the toxicity of POTS has been investigated. BALB/cA mice were exposed to aerosolized water-based NFPs containing POTS, and solutions of hydrolyzed POTS in methanol, ethanol, and 2-propanol, respectively. No acute respiratory effect was observed at exposure concentrations up to 110 mg/m³ with an aqueous solution of POTS. However, exposure to POTS in methanol resulted in a decrease of the tidal volume--an effect that did not resolve within the recovery period. After 27 min of exposure, the tidal volume had decreased by 25%, indicating partial alveolar collapse. For POTS in ethanol and 2-propanol, a 25% reduction of the tidal volume was observed after 13 and 9 min, respectively; thus, the tidal volume was affected by increase of the chain length. This was confirmed in vitro by investigating lung surfactant function after addition of POTS in different solvents. The addition of vaporized methanol, 2-propanol, or acetone to aerosolized POTS in methanol further exacerbated the tidal volume reduction, demonstrating that the concentration of vaporized solvent participated in the toxicity of POTS.

Short-term immunological effects of non-ethanolic short-chain alcohols.

Short-chain alcohols are embedded into several aspects of modern life. The societal costs emanating from the long history of use and abuse of the prototypical example of these molecules, ethanol, have stimulated considerable interest in its general toxicology. A much more modest picture exists for other short-chain alcohols, notably as regards their immunotoxicity. A large segment of the general population is potentially exposed to two of these alcohols, methanol and isopropanol. Their ubiquitous nature and their eventual use as ethanol surrogates are predictably associated to accidental or deliberate poisoning. This review addresses the immunological consequences of acute exposure to methanol and isopropanol. It first examines the general mechanisms of short-chain alcohol-induced biological dysregulation and then provides a tentative model to explain the molecular events that underlie the immunological dysfunction produced by methanol and isopropanol. The time-related context of serum alcohol concentrations in acute poisoning, as well as the clinical implications of their short-term immunotoxicity, is also discussed.

The endothelial safety of using a gentian violet dry-ink "S" stamp for precut corneal tissue.

PURPOSE: To determine the endothelium damage resulting from the application of "dry" gentian violet (GV) stromal markings on corneas precut for Descemet stripping automated endothelial keratoplasty (DSAEK) using a Moria "S" Stamp. METHODS: Five precut corneas had the stromal graft bed marked with GV using the Moria "S" stamp and 6 precut corneas were left unmarked as controls. After applying the ink to the stamp, care was taken to allow the alcohol carrier to dry for 10 seconds before applying the dry dye to the stromal surface. Tissue was then trephinated and stained with calcein AM to assess endothelial viability. Grafts were photographed and digital pixel planometry, using an established analysis technique, was used to compare the damage between the control and experimental groups. RESULTS: The mean percent cell damage of corneas treated with GV "S" stamp (n = 5) was 8.6% (range 4.4-12.9), and it was 8.1% (range 3.9-15.1) in the DSAEK control set (n = 6). Median percent cell damage was 6.7% among GV-treated corneas and 7.4% among control corneas. The distributions were not significantly different between groups (Mann-Whitney U test = 15.0, two-tailed P = 1.0). Moreover, no "S" pattern of damage was seen in any study eye. CONCLUSIONS: There were no significant differences in endothelial damage between the 2 groups. GV stromal markings may be applied without undue damage to the endothelium using the dry-ink technique described.

[Increase of general toxic effects and decrease of hepatocarcinogenic effects of diethylnitrosamine administered to mice in conjunction with isopropanol].

It is considered that diethylnitrosamine (DENA) is metabolized mostly in the liver with producing highly reactive compounds alkylating cellular macromolecules and causing toxic and carcinogenic effects. However, competitive inhibition of cytochrome P450 2E1, which metabolizes DENA, by its other substrate, isopropanol, does not weaken, but enhances the toxicity of DENA effect on mice and reduces the number of preneoplastic nodules and liver tumors induced by it. In short-term tests for mutagenicity (in the Ames test and the SOS-hromotest) DENA causes moderate damage of DNA that reduces liver microsomal enzymes, that metabolize nitrosamines. The obtained data indicate the predominant role of the initial compound as compared to its metabolites in toxic, and probably hepatocarcinogenic, effects on DNA in mice.

Genotoxic damage induced by isopropanol in germinal and somatic cells of Drosophila melanogaster.

Isopropanol (isopropyl alcohol, 2-propanol, IPA) is a volatile solvent widely used in domestic or industrial environments and reported as innocuous in various test systems. The aim of this work was to search for in vivo genotoxic effects of IPA in Drosophila melanogaster, studying its ability to induce nondisjunction (ND) in females, sex linked recessive lethals (SLRL) in males, and somatic mutation and/or recombination (SMART) in larvae. Treatments were acute (60min) and were administered via inhalation. IPA had low toxicity in adult flies (75% IPA mortality index, MI=12.7% (females) and 2.6% (males)) and larvae (MI=14.3%, 75% IPA). Female fertility was severely affected during the first 24h (brood I, BI) after treatment, but, afterwards, control values were recovered. IPA induced a 50-fold increase of ND (%) in 24h old females, and a six-fold rise in 4-5 d old BI offspring. Nondisjunction frequencies (%) in the offspring of broods II to V (24h in each case) were similar to control values. IPA doses of 25% and 50% (v/v), tested in 24h old females, showed a significant dose-dependent increase of ND(%)in BI only, with control values in subsequent broods. Flies gave normal offspring when kept in regular media for 24h before mating. The eye spot test (SMART) showed a significant increase at 50% IPA (p<0.05, m=2), but the response was not dose-dependent. IPA failed to induce SLRL in any of the spermatogenesis stages tested. These findings suggest that the main effect of IPA is to induce chromosomal malsegregation; IPA must be present at the resumption of M-phase I after fertilization, to exert these effects. The alcohol does not affect DNA directly, but perturbations of the nuclear membrane may be responsible for induction of ND.

Evaluation of cell-disruption effects of pulsed-electric-field treatment of Synechocystis PCC 6803.

In order to use Synechocystis PCC 6803 as feedstock of nonpetroleum-based diesel fuel, pulsed electric field (PEF) technology was used for cell disruption prior to extraction of intracellular lipids. Severe cell disruption was evident after PEF treatment, especially with treatment intensity (TI) > 35 kWh/m(3). Temperature increase during the treatment brought about most of the destruction of autofluorescence compounds, as well as a fraction of inactivation and the destruction of the plasma and thylakoid membranes. However, the forces associated with the pulsing electric field caused significant damage to the plasma membrane, cell wall, and thylakoid membrane, and it even led to complete disruption of some cells into fragments, which resulted in biomass loss. Treatment by PEF enhanced the potential for the low-toxicity solvent isopropanol to access lipid molecules during subsequent solvent extraction, leading to lower usage of isopropanol for the same extraction efficiency. Thus, PEF shows promise for lowering the costs and environmental effects of the lipid-extraction step.

Oxidation of methanol, ethylene glycol, and isopropanol with human alcohol dehydrogenases and the inhibition by ethanol and 4-methylpyrazole.

Human alcohol dehydrogenases (ADHs) include multiple isozymes with broad substrate specificity and ethnic distinct allozymes. ADH catalyzes the rate-limiting step in metabolism of various primary and secondary aliphatic alcohols. The oxidation of common toxic alcohols, that is, methanol, ethylene glycol, and isopropanol by the human ADHs remains poorly understood. Kinetic studies were performed in 0.1M sodium phosphate buffer, at pH 7.5 and 25°C, containing 0.5 mM NAD(+) and varied concentrations of substrate. K(M) values for ethanol with recombinant human class I ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, and ADH1C2, and class II ADH2 and class IV ADH4 were determined to be in the range of 0.12-57 mM, for methanol to be 2.0-3500 mM, for ethylene glycol to be 4.3-2600mM, and for isopropanol to be 0.73-3400 mM. ADH1B3 appeared to be inactive toward ethylene glycol, and ADH2 and ADH4, inactive with methanol. The variations for V(max) for the toxic alcohols were much less than that of the K(M) across the ADH family. 4-Methylpyrazole (4MP) was a competitive inhibitor with respect to ethanol for ADH1A, ADH1B1, ADH1B2, ADH1C1 and ADH1C2, and a noncompetitive inhibitor for ADH1B3, ADH2 and ADH4, with the slope inhibition constants (K(is)) for the whole family being 0.062-960 µM and the intercept inhibition constants (K(ii)), 33-3000 µM. Computer simulation studies using inhibition equations in the presence of alternate substrate ethanol and of dead-end inhibitor 4MP with the determined corresponding kinetic parameters for ADH family, indicate that the oxidation of the toxic alcohols up to 50mM are largely inhibited by 20 mM ethanol or by 50 µM 4MP with some exceptions. The above findings provide an enzymological basis for clinical treatment of methanol and ethylene glycol poisoning by 4MP or ethanol with pharmacogenetic perspectives.

Ethylene glycol, methanol and isopropyl alcohol intoxication.

In clinical practice, poisoning with ethylene glycol, methanol, and isopropyl alcohol is common. These alcohol-related intoxications can present with high anion gap metabolic acidosis and increased osmolality. Toxicity and clinical symptoms are due to the accumulation of their metabolites, causing increased anion gap, rather than the parent compounds that are associated with an increase of serum osmolality. Clinical manifestations result from abnormalities of neurologic, cardiopulmonary, and renal function. Laboratory abnormalities when present are helpful for diagnosis but may be absent depending on the time of ingestion and time of presentation. Fomepizole and ethanol are potent inhibitors of alcohol dehydrogenase and reduce generation of toxic metabolites. Hemodialysis is an effective way of detoxification because it can remove unmetabolized alcohol in addition to the organic anions. High index of suspicion and early diagnosis can prevent the significant morbidity and mortality associated with these intoxications.

Review of reproductive and developmental toxicity studies with isopropanol.

Published studies for reproductive and developmental toxicity conducted with isopropanol have been conducted by the inhalation and oral gavage routes of administration. Interpretation of the data from these studies has resulted in discussions regarding NOAELs and additional benchmark dose modeling publications. Unpublished reproductive and developmental toxicity studies administered in the drinking water were also conducted by BIBRA, and the results of those studies are presented here. In addition, all of the reproductive and developmental toxicity studies conducted with isopropanol are summarized and evaluated for concordance of effects and NOAELs. Endpoints of concern for regulatory agencies were decreases in male mating index and reductions in postnatal pup survival. Original study reports were evaluated and data collated to address these two endpoints, and the data summarized. Data are presented suggesting that there were technical problems in the study that implied a decrease in male mating index, and based on the results from the drinking water studies, the weight of evidence suggests that isopropanol does not affect male mating or fertility at dose levels of up to 1000 mg/kg/day. The weight of evidence suggests that isopropanol can cause decreases in postnatal pup survival following oral gavage administration of 1000-1200 mg/kg/day to the dams. The NOAEL for this endpoint with oral gavage administration was 700 mg/kg/day. Indications of maternal toxicity were also an important predictor for decreased postnatal survival. Decreased postnatal pup survival was also noted in the drinking water studies with isopropanol with a LOAEL of 2278 mg/kg/day and a NOAEL of 1947 mg/kg/day.