Delayed cognitive and psychiatric symptoms following methyl iodide and manganese poisoning: Potential for misdiagnosis

A New Strategy for Identification of Coal Miners With Abnormal Physical Signs Based on EN-mRMR

Coal miners’ occupational health is a key part of production safety in the coal mine. Accurate identification of abnormal physical signs is the key to preventing occupational diseases and improving miners’ working environment. There are many problems when evaluating the physical health status of miners manually, such as too many sign parameters, low diagnostic efficiency, missed diagnosis, and misdiagnosis. To solve these problems, the machine learning algorithm is used to identify miners with abnormal signs. We proposed a feature screening strategy of integrating elastic net (EN) and Max-Relevance and Min-Redundancy (mRMR) to establish the model to identify abnormal signs and obtain the key physical signs. First, the raw 21 physical signs were expanded to 25 by feature construction technology. Then, the EN was used to delete redundant physical signs. Finally, the mRMR combined with the support vector classification of intelligent optimization algorithm by Gravitational Search Algorithm (GSA-SVC) is applied to further simplify the rest of 12 relatively important physical signs and obtain the optimal model with data of six physical signs. At this time, the accuracy, precision, recall, specificity, G-mean, and MCC of the test set were 97.50%, 97.78%, 97.78%, 97.14%, 0.98, and 0.95. The experimental results show that the proposed strategy improves the model performance with the smallest features and realizes the accurate identification of abnormal coal miners. The conclusion could provide reference evidence for intelligent classification and assessment of occupational health in the early stage.

Misdiagnosis in occupational and environmental medicine: a scoping review

Introduction

There has been no comprehensive review for misdiagnosis in Occupational and Environmental Medicine (OEM). The possible ramifications of an occupational disease (OD) or an environmental disease (ED) misdiagnosis are not just confined to the individual case but may extend to others exposed to the occupational or environmental hazard. Therefore, a comprehensive scoping review of published literature is imperative for understanding the nature of misdiagnoses in OEM.

Methods

A medical librarian searched MEDLINE (PubMed), EMBASE, and the Cochrane Library (on 06 November 2020). All collected OEM misdiagnoses were classified based on 2 conceptual frameworks, the typical framework, and the causation model. The distribution of misdiagnosis across each medical specialty, each diagnostic step of the typical framework and the causation model, and false-negative and false-positive were summarized.

Results

A total of 79 articles were included in the scoping review. For clinical specialty, pulmonology (30 articles) and dermatology or allergy (13 articles) was most frequent and second-most frequent, respectively. For each disease, occupational and environmental interstitial lung diseases, misdiagnosed as sarcoidosis (8 articles), and other lung diseases (8 articles) were most frequent. For the typical framework, the most vulnerable step was the first step, evidence of a disease (38 articles). For the causation model, the first step, knowledge base, was the most vulnerable step (42 articles). For reported articles, the frequency of false-negative (55 articles) outnumbered the frequency of false-positive (15 articles).

Discussion

In OEM, compared to general medicine, causal misdiagnosis associated with the probability of causation is also important. For making a diagnosis in OEM, a knowledge base about possible ODs and EDs is essential. Because of this reason, the education and training of treating physicians for common ODs and EDs are important. For ODs and EDs, various intentional behaviors of stakeholders should be considered. This scoping review might contribute to the improvement of understanding for misdiagnosis in OEM.

Supplementary Information

The online version contains Supplementary theoretical review and Supplementary materials available at 10.1186/s12995-021-00325-z.

Manganese Chloride Exposure Causes Disorder of Energy Metabolism and Induces Oxidative Stress and Autophagy in Chicken Liver

Manganese (Mn) pollution is an important environmental problem because of the potential toxicity to human and animal health. However, the effects of Mn on energy metabolism and autophagy are not clear. Consequently, we examined the effects of excessive and chronic exposure to Mn on liver function, oxidative stress, respiratory chain complex activity, and autophagy in chicken liver. Our results indicated that the accumulation of Mn in the liver and levels of AST and ALT in the serum of the Mn-exposed group were significantly higher (P < 0.05) than those in the control group at 90 days; the activities of GSH-Px, SOD, CAT, Na⁺-K⁺-ATPase, Mg²⁺-ATPase, Ca²⁺-ATPase, and respiratory chain complexes (I, II, III) in the Mn-exposed group were significantly decreased (P < 0.05) compared to the control group. However, the MDA content, NO content, iNOS activity, mRNA and protein levels of iNOS, and autophagy-related genes in the Mn-exposed group were significantly increased (P < 0.05) compared to the control group. In contrast, the mRNA level and protein expression of mTOR were significantly decreased (P < 0.05) compared to the control group. Furthermore, the characteristic autophagic vacuolar organelles were observed in the Mn-exposed group. These results suggested that excess Mn exposure can cause a disorder of energy metabolism by mitochondrial injury and induce oxidative stress and autophagy, which eventually lead to liver damage.

Neuropsychiatric manifestations of methyl iodide toxicity

Methyl iodide is an industrial chemical used in methylation for pharmaceutical intermediates. Its toxicity is a rare industrial hazard. Its toxicity is reported with both acute sudden exposure and gradual exposure. The authors report a case of methyl iodide toxicity occurring in a 47 year-old male with sudden exposure to this chemical. He presented with neuropsychiatric symptoms primarily slurring of speech, ataxia followed by delusion and hallucinations which resolved within 2 weeks with parenteral thiamine and an antipsychotic. Symptoms reappeared after a re-exposure, this time with more prominent psychiatric symptoms which were late to resolve (4 weeks) with similar treatment. Neuroimaging revealed hyperintensities in posterior regions of the brain which resolved after 4 weeks. The patient had prominent neurocognitive deficits which were persistent. The case highlights the rare chemical toxicity with neuropsychiatric manifestations with persistent neurocognitive symptoms.

PET imaging of dopamine release in the frontal cortex of manganese-exposed non-human primates

Humans and non-human primates exposed to excess levels of manganese (Mn) exhibit deficits in working memory and attention. Frontal cortex and fronto-striatal networks are implicated in working memory and these circuits rely on dopamine for optimal performance. Here, we aimed to determine if chronic Mn exposure alters in vivo dopamine release (DAR) in the frontal cortex of non-human primates. We used [¹¹ C]-FLB457 positron emission tomography with amphetamine challenge to measure DAR in Cynomolgus macaques. Animals received [¹¹ C]-FLB457 positron emission tomography scans with and without amphetamine challenge prior to Mn exposure (baseline), at different time points during the Mn exposure period, and after 10 months of Mn exposure cessation. Four of six Mn-exposed animals expressed significant impairment of frontal cortex in vivo DAR relative to baseline. One Mn animal had no change in DAR and another Mn animal expressed increased DAR relative to baseline. In the reversal studies, one Mn-exposed animal exhibited complete recovery of DAR while the second animal had partial recovery. In both animals, frontal cortex Mn concentrations normalized after 10 months of exposure cessation based on T1-weighted magnetic resonance imaging. D1-dopamine receptor (D1R) autoradiography in frontal cortex tissue indicates that Mn animals that experienced cessation of Mn exposure expressed D1R levels that were approximately 50% lower than Mn animals that did not experience cessation of Mn exposure or control animals. The present study provides evidence of Mn-induced alterations in frontal cortex DAR and D1R that may be associated with working memory and attention deficits observed in Mn-exposed subjects.