Methanol Poisoning Research Articles

B-316 Retrospective Data Analysis Reveals Unusual Metabolism Pattern of Ethanol in Pediatrics as Compared to Adult and Geriatric Populations

Abstract Background Ethanol is utilized in many pharmaceutical formulations and in the treatment of methanol poisoning. It is also consumed recreationally and is the most abused drug globally. About 95% of consumed ethanol is metabolized by alcohol dehydrogenase into acetaldehyde, followed by conversion of the acetaldehyde into acetic acid by acetaldehyde dehydrogenase. Less than one percent is metabolized via nonoxidative pathways, which may include: glucuronidation, sulfation, and the formation of fatty acid esters of ethanol. In neonates the glucuronidation pathway has been reported to be underdeveloped and matures with age. In this work, the patterns and concentrations of phase II nonoxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), were assessed in random urine collections of pediatric, adult, and geriatric patients. Methods Test results (n = 63498) from urine samples tested for EtG and EtS by quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) at our facility were utilized for this study. For both analytes, the lower limit of positivity was 100 ng/mL. The age range under consideration was 0–100 years. Data was partitioned into age groups: 0–17 years, 18–80 years and 81–100 years. The EtG and EtS concentrations across the partitions were compared. Results Across all ages, 60%–65% of patients had both EtG and EtS present in urine. Between 5%–10% had EtG present without EtS, and 25%–35% of patients had neither of the ethanol metabolites present. In all age groups there was a low positivity rate of EtS without the presence of EtG (0%–1%). All age partitions showed a similar pattern with the highest percentages of patients showing the presence of both metabolites, and the lowest percentage of patients showing the presence of EtS only. Markedly, there were no pediatric patient samples that had the sulfated metabolite present in the absence of the glucuronidated metabolite; this was statistically significantly different than this proportion in adults (Fisher’s Exact test, P = 0.025). This finding suggests greater glucuronidation activity in the pediatric population. Conclusion From the data presented in this work, EtG is more prevalent relative to EtS in urine samples of patients assessed for ethanol exposure. This work also shows that glucuronidation may be the predominant pathway for ethanol metabolism in pediatric populations. Although the level and frequency of ethanol exposure, as well as the time between exposure and sampling were unknown for the patients studied, the data offers insights into the relative distribution of EtG and EtS in random urine samples for pediatric and adult populations.

Assessing the prognostic effects of hematologic indices in mortality of patients with methanol poisoning

Background: Methanol poisoning is an important cause of death, especially in countries where alcohol consumption is forbidden by law.

A rare lentiform fork sign in a patient with methanol intoxication with neurological sequelae of parkinsonism and cognitive dysfunction: A case report and literature review

Methanol intoxication is rare in developed countries. Early identification and elimination of the methanol metabolites are vital to an optimal prognosis. A characteristic brain imaging finding is bilateral basal ganglia necrosis and subcortical white matter changes. Here, we report a rare neuroradiological feature called the lentiform fork sign in a patient with methanol intoxication who survived the acute poisoning stage. We report a 31-year-old woman who presented to the emergency department with acute-onset incoherent speech, consciousness disturbance, and a high-anion-gap metabolic acidosis caused by methanol intoxication. She was treated with antidote administration of fomepizole and enhanced methanol elimination through hemodialysis. Neurological sequelae of cognitive decline and parkinsonism developed, with preserved vision. Brain MRI showed bilateral putaminal necrosis and subcortical white matter changes. The apparent diffusion coefficient map showed low signal intensities in the putamen and globus pallidus bilaterally, with brightly hyperintense rims surrounding both putamina that resembled a fork, indicating a lentiform fork sign. She then had sequelae of cognitive decline and delayed parkinsonism feature, which are compatible with the brain lesions on neuroimage studies. Methanol poisoning is an uncommon life-threatening event, and neurological sequelae result from the accumulation of formic acid, a methanol metabolite that inhibits cytochrome c oxidase in mitochondria, leading to neuronal injury. Methanol intoxication should be considered in patients with imaging findings of bilateral basal ganglia necrosis with lentiform fork sign and a metabolic acidosis of unknown origin.

Detection of Toxic Contaminants in Alcohol-Based Hand Sanitizers Using Infrared Spectroscopy

Recent fatalities due to methanol and 1-propanol toxicity in alcohol-based hand sanitizers has led the U.S. Food and Drug Administration (FDA) to ban 594 different hand sanitizer brands. The FDA also introduced methanol testing in alcohol-based hand sanitizers before allowing the products to enter the United States This requirement creates a need for inexpensive, rapid, and portable testing methods to measure methanol and 1-propanol concentrations in alcohol-based hand sanitizers. Here we study the performance of infrared (IR) spectroscopy for measuring methanol and 1-propanol concentrations in an alcohol-based hand sanitizer, and compare the performance of two portable spectrometers, Texas Instruments near-infrared (NIR) spectrometer (TI NIR) and NeoSpectra mid-infrared (MIR) spectrometer. The IR absorbance spectra were measured in transmission mode at different path lengths for 52 different hand sanitizer samples spiked with 0%–1% v/v concentrations of methanol and 1-propanol. A partial least-squares regression analysis shows ability to detect contaminant concentrations with a correlation coefficient of determination ( r2) up to 0.99 and root mean square error of prediction as low as 0.34% v/v.

A case of levodopa responsive parkinsonism due to methanol toxicity, an impact of COVID-19 crisis

A case of levodopa responsive parkinsonism due to methanol toxicity, an impact of COVID-19 crisis

Poisoning with methanol and other non-beverage alcohols - an analysis of the issue based on hospitalizations in department of toxicology

Introduction: Poisonings with non-beverage alcohols remain a significant problem in contemporary toxicology. Due to the large quantity and severe course of intoxications with methanol, the authors of this study focused primarily on poisonings with this substance. Methanol is widely used in industry. Its toxicity is attributed to its metabolites - formaldehyde and formic acid. Poisonings with methanol often lead to the patient's death due to a wide range of complications associated with progressive metabolic acidosis.
 Material and Methods: The study is of a retrospective nature. It involved the analysis of medical records of patients admitted to the department of toxicology in 2022 after the consumption of non-beverage alcohols, with a particular focus on methanol. Data on the number of individuals admitted due to non-beverage alcohol intoxication between 2018 and 2022 was also analyzed.
 Results: Over the last 5 years (2018-2022), 36 individuals were hospitalized in the Clinical Toxicological-Cardiological Department due to non-beverage alcohol poisoning, with 16 (44.4%) cases involving methanol. In the year 2022, the department admitted 10 individuals aged 18 to 68, and 5 (50%) of them consumed methanol. Among the hospitalized, 90% were male, and 60% came from rural areas. Deliberate intoxications accounted for 70% of the cases. Four hospitalizations (40%) resulted in patient death. All deaths were associated with methanol intoxication.
 Conclusions: Non-beverage alcohol is often used by people with alcohol dependence syndrome. Among non-beverage alcohols, patients most often reached for methanol. Its consumption is associated with a high mortality rate and should be taken very seriously and treated immediately.

Tertiary referral hospital experience of methanol poisoning in the COVID-19 era: a cross-sectional study in Northwestern Iran

BackgroundMethanol poisoning is a worldwide phenomenon that has resulted in deaths and irreversible complications. However, studies show it is more prevalent in developing countries and areas with lower socioeconomic status. So, accurately recognizing socio-economic risk factors, increasing people's awareness about methanol poisoning, and proper hospital management will reduce its dangerous complications and mortality.MethodsThis cross-sectional study was conducted retrospectively at Sina Hospital, a poisoning center and tertiary referral center in northwestern Iran, and investigated demographic findings and hospital management indicators through systematic random sampling between February 20, 2020, and September 22, 2022 (or the COVID-19 era). We assessed variable correlations using Spearman's correlation coefficient, Mann–Whitney U, and Kruskall–Wallis.ResultsOut of 131 patients, 126 (96.2%) were males, and 5 (3.8%) were females. 45.5% and 30.3% of poisoning incidents occurred between the winter and spring, respectively. 67 patients (50.8%) were referred to this hospital due to vision complaints. Unfortunately, 10 patients (7.6%) passed away despite receiving care. Employed individuals were referred to the treatment facility more quickly than unemployed individuals (P-value = 0.01). Patients with medical insurance coverage were referred faster after consuming alcohol (P-value = 0.039). Older patients referred to the hospital later. (P-value = 0.006).ConclusionsMortality and morbidity following methanol poisoning are likely to be affected by factors including access to medical care, financial stability, and employment status. Consequently, reducing mortality and morbidity requires attention to these concerns.

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

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. 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. 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. 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 left eye temporal RNFL, right eye temporal RNFL, and the latency P1 of VEP in the left eye were significant. 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.

Outcomes of pediatric ingestions of alcohol-based hand sanitizers during the COVID-19 pandemic

Introduction In July 2020, an outbreak of methanol-contaminated hand sanitizers in the United States prompted our regional poison center to implement a more conservative triage guideline for hand sanitizer exposures. All pediatric hand sanitizer ingestions of more than a “taste” were referred to a healthcare facility for assessment. We then evaluated the effect of this change on identifying patients with methanol poisoning. Methods This was a single-center, retrospective review of pediatric (<19 years) hand sanitizer ingestions reported to our poison center from May 1, 2020 through January 28, 2022. Methanol and ethanol concentrations were collected if available. Results During the study period, we received 801 calls regarding hand sanitizer exposure, of which 140 children were referred to a healthcare facility for hand sanitizer ingestions. Of those, 88 (63%) had methanol and/or ethanol concentrations measured. No child had a detectable methanol concentration, 78 had ethanol testing, and 12 had a detectable ethanol concentration. Conclusions In this sample, no patient tested had a detectable methanol concentration. Children who consumed enough to have a detectable ethanol concentration were symptomatic or had an intentional ingestion. Asymptomatic children with unintentional ingestion of hand sanitizer were at low risk for methanol toxicity.

Is optic nerve sheath diameter diagnostic in methanol intoxication?

Background and aimMethyl alcohol intoxication causes severe morbidity and mortality, especially in developing countries. Formic acid is formed as a result of methanol metabolism. Formic acid accumulation and inhibition of adenosine triphosphate synthesis result in ophthalmic issues. This study aimed to demonstrate that the optic nerve sheath diameter (ONSD) measurement is an accurate prognostic marker and can be helpful in the diagnosis of methanol intoxication. Materials and methodsThis prospective study was conducted with 52 patients who were admitted to the emergency department after alcohol consumption and agreed to participate in the study. Age, gender, comorbid diseases, vital signs, ONSD ultrasonography measurements, hospitalization and discharge status, in-hospital mortality status, dialysis need, presence of visual impairment, blood gas parameters, respiratory status, time since alcohol intake, ethanol levels, urea levels, and creatinine levels were analyzed. ResultsROC curve analysis was performed to evaluate the predictive power of ONSD to diagnose methanol intoxication. The area under the curve was 0.857 for the cut-off value of 5.05 mm (95 % CI: 0.728–0.985; p < 0.001), with a sensitivity of 80.8 % and a specificity of 100 %. In the regression analysis performed to determine the prognostic value of the parameters in estimating mortality in methanol intoxication cases, an increase in ONSD (OR: 3.619; 95 % CI: 0.057–0.199; p = 0.001), an increase in lactate levels (OR: 5.653; 95 % CI: 0.040–0.085; p < 0.001), and increased duration after alcohol intake (OR: 2558; 95 % CI: 0.004–0.034; p = 0.014) were identified as independent predictors of mortality, but pH, HCO3, and base deficit levels were not significant predictors. ConclusionsWe believe that ONSD can be helpful for the differential diagnosis and prognosis of patients with suspected methanol toxicity who presented with alcohol intake.

Prevalence and predicting factors of acute kidney injury due to methanol intoxication; a systematic review

Introduction: Methanol intoxication and subsequence acute kidney injury (AKI) can be dangerous and deadly in case of a missed or delayed diagnosis; therefore, identifying its prevalence and predictor factors is necessary. Objectives: This study was conducted to identify the prevalence and predictor factors of AKI in methyl alcohol-intoxicated patients. Methods and Materials: The search strategy was conducted with the standard keyword in the international database, including Web of Science, Scopus, PubMed /Medline, Embase, Cochrane, WorldCat, Dimension, OpenGrey, EBSCO, DOAJ, CINAHL, and Google scholar search engines. Studies that reported the prevalence of AKI due to methanol poisoning were included in this review study. Results: Results demonstrated that six studies from five countries, with a sample size of 816 methanol intoxication patients, were included in this study. Mean AKI prevalence in all reviewed studies was 28.18%; Gender male, hypertension, older age, anemia, alcohol addiction, metabolic acidosis, high blood osmolality, high Formate concentration, alcohol overdose, sepsis, rhabdomyolysis, acute pancreatitis, and volume depletion were the reported AKI predictors in the reviewed studies. Conclusion: Identifying the AKI prevalence and its predictor factors in patients with methanol intoxication can help in their quick diagnosis, timely treatment, and reduce the subsequent complications.

Follow-up of Methanol-related Visual Defects in a Cohort Study: Initial Severity Predicts Long-term Outcome.

Methanol poisoning can occur either intentionally through the consumption of methanol-containing products or accidentally through ingestion, resulting in visual impairment. We assessed the long-term visual sequelae in patients with methanol poisoning. This prospective cohort study was conducted at referral centers, Khorshid and Alzahra University Hospitals, affiliated with Isfahan University of Medical Sciences, Isfahan, Iran. The study included patients hospitalized for methanol poisoning from June 22, 2018, to June 21, 2020, with follow-up extended until June 2021. Toxico-clinical and ophthalmologic examination data were collected from patients upon hospital admission, discharge, and during follow-up. Thirty-nine patients were assessed in this study. The majority of them (94.9%) were male, with an average age of 34 years. Patients who presented with reduced visual acuity (VA) upon admission subsequently showed abnormalities (in acuity and visual fields) during follow-up (n = 13). Among the patients who displayed visual field defects on admission, bilateral optic disc atrophy was observed in follow-up (n = 13). Conversely, patients who reported blurred vision, with or without photophobia upon admission, had normal results in their follow-up eye examinations. Among the 36 patients who underwent dialysis, 14 (38.9%) exhibited visual impairment during follow-up examinations. Additionally, 38 patients received sodium bicarbonate, and 14 of them (36.85%) also presented ocular abnormalities. Patients who demonstrated VA deficits upon admission are more likely to experience long-term VA and visual field defects, as well as optic disc atrophy. Patients who solely complained of blurred vision, with or without photophobia, during admission were less likely to develop long-term visual defects.

Facile synthesis of ultrathin S-N co-doped carbon nanosheet as ORR electrocatalysts for application in sustainable zinc-air battery

The exploration of inexpensive, efficient electro-materials for oxygen reduction reactions in the field of zinc-air batteries has attracted the attention of researchers. Metal-free carbon catalysts with adulteration heteroatoms have been considered in recent years as the most promising alternative to conventional Pt-based electrocatalysts. Herein, we have researched a simple and high-performance grinding and pyrolyzing strategy for the preparation of S-N co-doped carbon nanosheets (S-N-C) with a 3D ultrathin structure that serves as resultful catalysts for ORR in zinc-air batteries. As expected, the prepared S-N-C 1000 catalysts have a super-colossal specific surface area and exhibit splendid ORR catalytic performance with half-wave potentials up to 0.858 V, which is superior to Pt/C. Furthermore, S-N-C 1000 catalysts show good stability and resistance to methanol poisoning. Additionally, the zinc-air batteries employing S-N-C 1000 as the air cathode also show excellent electrochemical performance. The power density of 164.68 mW cm−2, the cycling stability of more than 600 h at 5 mA cm−2, and the specific capacity of 830.85 mAh gZn−1 point to a possible application in zinc-air batteries. Therefore, this effective and environmentally friendly synthetic method may present a novel use for non-metallic heteroatom-doped carbon materials in zinc-air batteries.

Outcome of Methanol Toxicity Outbreak In Saudi Arabia: Case Series Study.

Introduction Methanol poisoning is an acute medical emergency. If not recognized in time and treated properly, it can lead to a considerable magnitude of morbidity as well as mortality. This article aims to report cases of methanol toxicity, focusing on clinical presentation, management, and outcomes. Method Nine ICU-admitted patients with confirmed positive serum methanol levels wereanalyzed in a case series at King Fahad General Hospital in Jeddah, Saudi Arabia, between November 2022 and January 2023. Results Among the nine patients admitted to the ICU due to methanol poisoning, the majority were middle-aged males, with two females included. Gastrointestinal symptoms were seen in two-thirds of patients, while three patients required immediate mechanical ventilation due to a low Glasgow Coma Scale. Severe metabolic acidosis was observed in most cases. All patients received sodium bicarbonate and hemodialysis, with six patients also receiving fomepizole. However, two patients in the study with low initial low Glasgow Coma Scale (GCS), severe metabolic acidosis, and diffuse brain edema, did not survive. One patient reported acute complete vision loss. Conclusion This case series highlights the importance of promptly recognizing and managing methanol toxicity in ICU settings. The clinical presentation of methanol toxicity can be challenging, and early diagnosis and treatment are crucial to prevent irreversible damage.

Quantitative analysis of methanol in blood, urine, vitreous humor, and cerebrospinal fluid by using gas chromatography-head space in two suspected cases of methanol poisoning

Quantitative analysis of methanol in blood, urine, vitreous humor, and cerebrospinal fluid by using gas chromatography-head space in two suspected cases of methanol poisoning

Case Reports Study on Methanol Poisoning in King Abdul Aziz Specialist Hospital, Taif, Saudi Arabia

Methanol poisoning is a challenging issue due to its inducing acute multiple organ failures, and especially due to a lack of preparedness, available antidotes, and management protocols. The current study presents six cases of methanol poisoning that attended the emergency department of King Abdul Aziz Specialist Hospital, Taif, Saudi Arabia, between March and November 2022. All of the patients suffered from severe metabolic acidosis and visual impairment following the ingestion of homemade alcoholic beverages and colonia. Three patients were comatose, suffered from post-cardiac pulmonary arrest, and, finally, died, while the other three were non-comatose and discharged from the ICU after improvement. Management was based on clinical symptoms and other laboratory findings due to a shortage of methanol level measurement resources. The antidote, fomepizole, was not given to all of the cases due to its deficiency, and ethanol was given only to one patient due to difficulties in administering it without monitoring its concentration. Methanol poisoning and its outbreak provide insights into the dangers of hazardous homemade alcohol and other pharmaceutical preparations that might be adulterated with methanol, particularly to the shortage of suitable diagnostic testing and antidotes in addition to poor resources for management of intoxicated patients in some regions of Saudi Arabia.

#4238 UNEXPLAINED METABOLIC ACIDOSIS - A DIAGNOSTIC DILEMMA

Abstract Background and Aims Metabolic Acidosis is a common condition for which nephrology consult is sought. Most often the etiology is quite obvious like renal failure, diabetic ketoacidosis, lactic acidosis etc. We describe a case of high anion gap metabolic acidosis, unresponsive to medical management requiring hemodialysis, where finding the etiology became a diagnostic challenge because of medical and social reasons prevailing in this eastern part of India. Method A 55 year old obese gentleman came to emergency department at 3 am with complains of restlessness, pain abdomen and chest discomfort for last 4-6 hours. On clinical examination he had tachycardia with normal blood pressure and oxygen saturation. His sensorium was normal and systemic examination did not reveal any major abnormality. A possibility of acute cardiac event was considered but his ECG showed sinus tachycardia, echocardiography did not show any wall motion abnormality and Troponin I was less than 0.01 ng/mL. His blood gases showed an uncompensated metabolic acidosis with an anion gap of 21 (pH 7.19 / pCO2 44 / HCO3 15). The laboratory parameters showed a serum creatinine of 0.9 mg/dL, random blood sugar of 130 mg/dL. Any history of poisoning or drug overdose was denied by patient's attendants. Pending further workup patient was admitted in intensive care unit and correction of metabolic acidosis was started with intravenous sodium bicarbonate. Results The metabolic acidosis initially improved with medical management but within next 6 hours patient again had severe metabolic acidosis. Meanwhile patient's sensorium worsened and he had an episode of seizure. Patient was intubated and mechanical ventilation started. Within 30 minutes patient had status epilepticus which ultimately required intravenous thiopentone. Hemodialysis was started for correction of metabolic acidosis. Patient's history was re-evaluated. On persistent questioning his attendants admitted that patient had consumed alcohol 4-5 hours before the symptoms started. It is important to mention here that consumption of alcohol is a punishable offence in Bihar which a state in eastern part of India. Despite alcohol being completely banned in this part of country illicit alcohol is smuggled and consumed by some. Illicit alcohol is prone to be adulterated and sub-standard. It was because of this fact that patient's attendants suppressed the facts. Also alcohol consumption is a valid ground for rejection of medical insurance claims because of obvious reasons. After obtaining the complete history a possibility of consumption of alcohol adulterated with methyl alcohol was very likely. Serum methyl alcohol estimation was not available at our institute and patient had already received hemodialysis hence it was not done. With patient already having seizures MRI (Magnetic Resonance Imaging) of brain was done. MRI brain revealed altered hyperintense signal with cytotoxic edema in bilateral basal ganglia predominantly putamen. Subcortical white matter in bilateral cerebral hemisphere and bilateral optic nerve head showed restriction on diffusion weighted imaging. These typical features on MRI were highly suggestive of methanol toxicity. These MRI features along with the clinical scenario and history of illicit alcohol intake helped us reach the diagnosis of methanol toxicity. Patient was managed with hemodialysis sessions to remove methanol from blood until he improved clinically. Conclusion The etiology of the high anion gap metabolic acidosis turned out to be methanol toxicity. Typical MRI brain findings helped confirm the diagnosis. Our case highlights the importance of obtaining the correct medical history and how social and medicolegal issues sometimes become a hindrance to obtaining the same.

Boosting Oxygen Reduction Activity of Co3O4 through a Synergy of Ni Doping and Carbon Species Dotting for Zn-air Battery

Oxygen reduction reaction (ORR) undertakes an indispensable driving role for metal-air batteries with sluggish kinetics. In this work, we proposed a synergic strategy of Ni doping and carbon species dotting to compose Co3O4 with intrinsic large specific area and oxygen vacancies. The Ni-doped Co3O4/C (NCC-1) with four electron transfer mode conducts extraordinary electrocatalytic performance than commercial 20 wt% Pt/C and excellent tolerance to methanol poisoning. This series of improvements are attributed to the rapid dynamics drove by variable transition metal valence with elevated electronic conductivity derived from dotted carbon species. The XPS results at different reduction stages investigate that the doped Co3O4/C affects ORR performance by adjusting the species of *O at the active sites and the formation of intermediates including *OH and *O. More Co3+ active sites exposed on the NCC-1 surface, higher catalytic activity is provided by the conversion of Co(Ⅱ)/Co(III) and Ni(Ⅱ)/Ni(III). What is purposeful in practicability. the NCC-1/IrO2 based Zn-air batteries show an excellent charge-discharge response and cyclability than that of 20% Pt/IrO2 based Zn-air batteries, highlighting the implemented potentiality of NCC-1 based metal-air-battery. This study offers new insights into designing non-noble-metal based oxygen reduction electrocatalysts for more energy storage devices.

Methanol bioconversion in Methylotuvimicrobium buryatense 5GB1C through self-cycling fermentation

Methanol is an abundant and low-cost next-generation carbon source. While many species of methanotrophic bacteria can convert methanol into valuable bioproducts in bioreactors, Methylotuvimicrobium buryatense 5GB1C stands out as one of the most promising strains for industrialization. It has a short doubling time compared to most methanotrophs, remarkable resilience against contamination, and a suite of tools enabling genetic engineering. When approaching industrial applications, growing M. buryatense 5GB1C on methanol using common batch reactor operation has important limitations; for example methanol toxicity leads to mediocre biomass productivity. Advanced bioreactor operation strategies, such as fed-batch and self-cycling fermentation, have the potential to greatly improve the industrial prospects of methanotrophs growing on methanol. Herein, implementation of fed-batch operation led to a 26-fold increase in biomass density, while two different self-cycling fermentation (SCF) strategies led to 3-fold and 10-fold increases in volumetric biomass productivity. Interestingly, while synchronization is a typical trait of microbial populations undergoing SCF, M. buryatense 5GB1C cultures growing under this mode of operation led to stable, reproducible cycles but no significant synchronization.

Ocular Manifestations After Acute Methanol Poisoning

ABSTRACT Acute methanol poisoning is first and foremost life-threatening. Otherwise, functional prognosis is mainly based on ocular impairment. In this case series we aimed to describe the ocular manifestations after acute methanol poisoning during an outbreak in Tunisia. The data from 21 patients (41 eyes) were analysed. All patients underwent a complete ophthalmological examination including visual fields, colour vision test and optical coherence tomography with evaluation of the retinal nerve fibre layer. Patients were classified into two groups. Group 1 included patients with visual symptoms and group 2 included patients with no visual symptoms. Ocular abnormalities were seen in 81.8% of patients with ocular symptoms. They included: optic neuropathy in 7 patients (63.6%); central retinal artery occlusion in 1 patient (9.1%); and central serous chorioretinopathy in 1 patient (9.1%). Mean blood methanol levels were significantly higher in patients without ocular symptoms (p = .03).