Acute bilateral blindness caused by accidental methanol intoxication during fire "eating"

Höffding step and beyond: The impact of visual sensory impairment on cognitive performance in neuropsychological testing of survivors of acute methanol poisoning

BACKGROUND

Sensory deficits can result in limitations regarding how well neuropsychological test findings can be interpreted. Only a few studies have investigated the influence of vision alteration on neuropsychological tests. In 2012 the Czech Republic experienced mass methanol poisoning. Methanol metabolites cause histotoxic hypoxia to the optic nerve.

OBJECTIVE

In the current study, the effect of the toxic damage on the parts of the visual pathway on visual and non-visual neuropsychological measures was investigated using electrophysiological methods (visual evoked potential (VEP) and optical coherence tomography (OCT) with retinal nerve fibre layer (RNFL) thickness measurement.

METHODS

53 individuals who experienced methanol poisoning participated in this research (76% men; ages 24 to 74 years, mean = 43.8±14.6 years; education 11.9±1.4 years). Each participant underwent comprehensive neurological, ophthalmological, and neuropsychological examinations.

RESULTS

The results of mixed-effect models revealed significant small to a medium association between the Stroop test weak interference and Grooved Pegboard with the left eye global, nasal and temporal RNFL thickness. Also, medium associations between the Finger Tapping test and the Stroop test weak interference and OS temporal RNFL, right eye temporal RNFL, and the latency P1 of VEP in the left eye were significant.

CONCLUSION

The results of this study found a small to medium association (r = .15- .33; p = .010- .046) between RNFL thickness and cognitive visual test performance. Careful interpretation is suggested regarding results obtained from visual tests of the executive or motor functioning with participants with RNFL decrease or other types of early visual processing damage.

Methanol-induced optic neuropathy: a still-present problem

Methanol-induced optic neuropathy (Me-ION) is a serious condition that may result in long-term or irreversible visual impairment or even blindness secondary to damage and loss of function of the optic nerve and retina. Me-ION shows a tendency to occur as mass poisonings around the world with a clear predilection for poor societies in developing countries. The main mechanism underlying the molecular basis of Me-ION is the inhibition of the mitochondrial oxidative phosphorylation process through the binding of the toxic metabolite of methanol—formic acid—with the key enzyme of this process—cytochrome c oxidase. However, other mechanisms, including damage to the eye tissues by oxidative stress causing the intensification of the oxidative peroxidation process with the formation of cytotoxic compounds, as well as an increase in the synthesis of pro-inflammatory cytokines and influence on the expression of key proteins responsible for maintaining cell homeostasis, also play an important role in the pathogenesis of Me-ION. Histopathological changes in the eye tissues are mainly manifested as the degeneration of axons and glial cells of the optic nerve, often with accompanying damage of the retina that may involve all its layers. Despite the development of therapeutic approaches, persistent visual sequelae are seen in 30–40% of survivors. Thus, Me-ION continues to be an important problem for healthcare systems worldwide.

COVID casualty: Bilateral blindness due to ingestion of spurious sanitizer

Intentional ingestion of alcohol-based handrub (ABHR) or sanitizer solution is uncommon. The coronavirus disease-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 has led to lockdowns being put in place in many countries across the globe and resulted in a surge in ABHR usage to maintain hand hygiene. In this communication, we report the case of a 56-year-old male, a chronic alcoholic who presented during the lockdown period, with acute bilateral loss of vision following ingestion of ABHR. The handrub was found to be a nonstandardized sanitizer with no labels mentioning its constituents. Typically, the ingestion of ABHR solutions results in isopropanol or ethanol poisoning, both of which have low toxicity. Based on the clinical history and findings in our patient, a diagnosis of optic neuropathy due to accidental ingestion of sanitizer containing methyl alcohol as an unlisted ingredient was made. Our report underscores the need for strict guidelines, toxicovigilance, and surveillance systems to be in place to prevent such adulterated ABHRs from being commercially available.

Acute and delayed toxicity from co-ingestion of methylene chloride and methanol

Methylene chloride is a volatile, chlorinated hydrocarbon and colorless solvent found in multiple industrial products including paint strippers, metal cleaners, automotive products, pesticides and aerosol containers. Occupational exposure to methylene chloride is reported in automotive technicians, painters, and other industrial workers with adverse health effects including gastrointestinal, neurological, as well as hepato-renal injuries. International Agency for Research on Cancer (IARC) classifies methylene chloride as a 2 A carcinogen. Through a series of reactions catalyzed by cytochrome P450 2E1 (CYP2E1), metabolism of methylene chloride leads to the formation of formyl chloride, and ultimately carbon monoxide (CO). Most reports of methylene chloride toxicity are due to dermal and inhalational exposure in occupational settings. Ingestion of methylene chloride is uncommon, yet can lead to significant toxicity and prolonged CO toxicity. Methylene chloride is frequently formulated with methanol; individuals who intentionally ingest methylene chloride can experience concomitant methanol toxicity. We present a case of acute ingestion of paint stripper containing methanol and methylene chloride. We discuss the clinical presentation, key management decisions, relevant pathophysiology and biochemistry, as well as the clinical course and management.

Elevated urine formaldehyde in elderly patients with primary open angle glaucoma

AIM

To investigate the risk factor of primary open angle glaucoma (POAG), which is the leading cause of irreversible blindness worldwide. An abnormally high level of endogenous formaldehyde (FA) has recently been found correlated with cell death and neurodegenerative disease, raising the possibility of a putative correlation of abnormal endogenous FA with POAG.

METHODS

Thirty-four elderly patients with POAG and sixteen healthy controls were enrolled. Glaucomatous visual defects were present at both the functional (visual field) and structural [retinal nerve fiber layer (RNFL) thickness] levels. Morning urine samples were obtained and were analyzed by high-performance liquid chromatography (HPLC) to detect the endogenous FA level in a double blind manner.

RESULTS

Patients with POAG (P<0.05) had significantly higher urine FA levels. The urine FA level of patients with severe visual field defects [mean deviation (MD)≥12 dB] was significantly (P<0.001) greater than that of patients with mild to moderate defects (MD<12 dB). By optical coherence tomography (OCT), the superior and inferior RNFL thickness of POAG group was significantly (P<0.001) thinner than in controls. Furthermore, the superior and inferior thinning of the RNFL was correlated with the elevation of urine FA concentration.

CONCLUSION

Endogenous FA level is positively correlated with the neuronal defects of POAG.

Organic Solvent Effects in Biomass Conversion Reactions

Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes.

Bibliometric profile of the global scientific research on methanol poisoning (1902-2012)

BACKGROUND

Methanol poisoning is on the rise and has been associated with high morbidity and mortality; it has resulted in growing research in the field of toxicology. The aim of this study was to reveal underlying patterns in scientific outputs related to methanol poisoning at the global level by evaluating different bibliometric indices.

METHODS

We searched for publications that contained specific words regarding methanol poisoning in Scopus database.

RESULTS

A total of 912 articles, with 8,317 citations and with an average of 9.1 citations per document, were retrieved on methanol poisoning, and the bulk of the articles were published from the USA (20.9%), followed by Spain (4.4%), Canada (4.3%), India (3.1%), and France (3.0%). The articles were published belonging to 57 countries. No data related to methanol poisoning were published from 155 (73.1%) out of 212 countries. Twenty-one documents (2.3%) were published in Clinical Toxicology, whereas 18 (2.0%) were published in The Lancet.

CONCLUSIONS

Scientific production related to methanol poisoning is increasing. articles have been published in a wide range of journals with a variety of subject areas, most notably clinical toxicology; and the country with the greatest production was the USA.

Mitochondrial optic neuropathy: In vivo model of neurodegeneration and neuroprotective strategies

This review summarizes the characteristics of a rodent toxicologic model of optic neuropathy induced by the mitochondrial complex I inhibitor rotenone. This model has been developed to fulfill the demand for a drug-screening tool providing a sound mechanistic context to address the role of mitochondrial dysfunction in the pathogenesis of neurodegenerative disorders. It features biochemical, structural, and functional retinal deficits that resemble those of patients with Leber's hereditary optic neuropathy, a mitochondrial disease characterized by selective degeneration of retinal ganglion cells, and for which an environmental component is believed to play a major triggering role. The available data support the efficiency, sensitivity, and versatility of the model for providing insights into the mechanisms of neurodegeneration, including mitochondrial dysfunction, oxidative stress and excitotoxicity. Screening work with this model has provided proof-of-principle that interventions targeting the electron transport chain, such as USP methylene blue and near-infrared light therapy, are effective at preventing neurodegeneration induced by mitochondrial dysfunction in vivo. Prospective developments of this model include the use of neuronal reporter genes for in vivo non-invasive assessment of retinal degeneration at different time points, and its combination with genetic approaches to elucidate the synergism of environmental and genetic factors in neurodegeneration.

MRI findings in methanol intoxication: a report of two cases

Methanol is a highly toxic substance and acute methanol poisoning produces severe metabolic acidosis and serious neurological symptoms, including severe visual impairment, extrapyramidal signs and coma. Its similarity to ethanol in appearance and odour leads to accidental use. We present two cases of accidental methanol intoxication and discuss the MRI findings.