Bilateral and Symmetrical Lesions in the Basal Ganglia Associated With Metabolic Acidosis in a Patient With a History of Alcohol Addiction: A Case Report

Metabolic acidosis is defined as a pathologic process that, when unopposed, increases the concentration of hydrogen ions in the body and reduces the concentration of HCO3. Methanol poisoning is an important cause of metabolic acidosis. Methanol and ethylene glycol poisonings cause scores of fatal intoxications annually, and even relatively small ingestions of these alcohols can produce significant toxicity. Neuroimaging findings are very suggestive and help in the diagnosis even before the measurement of serum methanol (when available at the health service). Rapid recognition and early treatment, including alcohol dehydrogenase inhibition, are crucial. In this sense, some studies question that many intoxications by different chemical agents (in addition to methanol and ethylene glycol) generate a conglomeration of neuroimaging findings that summarily reflect the presence of metabolic acidosis. Therefore, in this article, we discuss the imaging findings of metabolic acidosis, methanol poisoning, and their main differential diagnoses in neuroimaging, directing earlier diagnostic reasoning in order to initiate the most appropriate treatment promptly.

Ambient carbon monoxide and daily mortality: a global time-series study in 337 cities

BACKGROUND

Epidemiological evidence on short-term association between ambient carbon monoxide (CO) and mortality is inconclusive and limited to single cities, regions, or countries. Generalisation of results from previous studies is hindered by potential publication bias and different modelling approaches. We therefore assessed the association between short-term exposure to ambient CO and daily mortality in a multicity, multicountry setting.

METHODS

We collected daily data on air pollution, meteorology, and total mortality from 337 cities in 18 countries or regions, covering various periods from 1979 to 2016. All included cities had at least 2 years of both CO and mortality data. We estimated city-specific associations using confounder-adjusted generalised additive models with a quasi-Poisson distribution, and then pooled the estimates, accounting for their statistical uncertainty, using a random-effects multilevel meta-analytical model. We also assessed the overall shape of the exposure-response curve and evaluated the possibility of a threshold below which health is not affected.

FINDINGS

Overall, a 1 mg/m³ increase in the average CO concentration of the previous day was associated with a 0·91% (95% CI 0·32-1·50) increase in daily total mortality. The pooled exposure-response curve showed a continuously elevated mortality risk with increasing CO concentrations, suggesting no threshold. The exposure-response curve was steeper at daily CO levels lower than 1 mg/m³, indicating greater risk of mortality per increment in CO exposure, and persisted at daily concentrations as low as 0·6 mg/m³ or less. The association remained similar after adjustment for ozone but was attenuated after adjustment for particulate matter or sulphur dioxide, or even reduced to null after adjustment for nitrogen dioxide.

INTERPRETATION

This international study is by far the largest epidemiological investigation on short-term CO-related mortality. We found significant associations between ambient CO and daily mortality, even at levels well below current air quality guidelines. Further studies are warranted to disentangle its independent effect from other traffic-related pollutants.

FUNDING

EU Horizon 2020, UK Medical Research Council, and Natural Environment Research Council.

Soy Biodiesel Exhaust is More Toxic than Mineral Diesel Exhaust in Primary Human Airway Epithelial Cells

As global biodiesel production increases, there are concerns over the potential health impact of exposure to the exhaust, particularly in regard to young children who are at high risk because of their continuing lung development. Using human airway epithelial cells obtained from young children, we compared the effects of exposure to exhaust generated by a diesel engine with Euro V/VI emission controls running on conventional diesel (ultra-low-sulfur mineral diesel, ULSD), soy biodiesel (B100), or a 20% blend of soy biodiesel with diesel (B20). The exhaust output of biodiesel was found to contain significantly more respiratory irritants, including NO_x, CO, and CO₂, and a larger overall particle mass. Exposure to biodiesel exhaust resulted in significantly greater cell death and a greater release of immune mediators compared to both air controls and ULSD exhaust. These results have concerning implications for potential global health impacts, particularly for the pediatric population.

Short- and long-term exposure to ambient air pollution and circulating biomarkers of inflammation in non-smokers: A hospital-based cohort study in South Korea

Despite increasing epidemiological evidence of an association between air pollution and adverse health outcomes, the detailed mechanisms underlying the adverse effects of air pollution on medical conditions remain unclear. We evaluated the effects of short- and long-term exposure to ambient air pollution on key inflammatory markers in non-smoking subjects. Serum fibrinogen, C-reactive protein, ferritin, and white blood cell counts were repeatedly measured 3 times in 6589 subjects at the Samsung Medical Center (Seoul, South Korea) between 2010 and 2016. Both short- (≤8-day averages) and long-term (annual averages) exposure measures of 6 air pollutants (particles < 2.5 μm, particles < 10 μm, nitrogen dioxide, sulfur dioxide, ozone, and carbon monoxide) were estimated for each subject based on available residential addresses. Linear mixed-effects models were used to relate interquartile range increases in pollutant concentrations to inflammatory marker levels. Short-term exposure to air pollution was associated with increased fibrinogen and ferritin levels. Long-term exposure to air pollution was associated with increased fibrinogen levels and white blood cell counts. The largest short- and long-term associations were observed for ferritin in response to nitrogen dioxide exposure (1.4%, 95% confidence interval [CI] 0.3-2.5) and fibrinogen exposed to particles < 2.5 μm (3.4%, 95% CI 3.0-3.8), respectively. Significantly higher associations were observed among subjects with elevated levels of inflammatory markers (upper 25th percentile), including C-reactive protein, and those with cardiac infarction, chronic obstructive pulmonary disease, cerebral infarction, or diabetes. We found clear associations between short- and long-term exposure to air pollution and inflammatory markers, especially among vulnerable subgroups. Our findings provide evidence in support of the hypothesis that air pollution increases systemic inflammation, particularly among susceptible subgroups.

The Tyr113His T/C rs1051740 and 'very slow' phenotype of the EPHX1 gene alters miR-26b-5p and miR-1207-5p expression in pregnancy

BACKGROUND

Environmental insults and microsomal epoxide hydrolase 1 (EPHX1) single nucleotide polymorphisms (SNPs), Tyr113His T/C rs1051740 and His139Arg A/G rs2234922, aberrantly alters microRNA (miR) expression and are linked to low birthweights (LBW).

OBJECTIVES

To investigate the interplay between pollution, EPHX1 SNPs and miRs during pregnancy and associated LBW outcomes.

METHODS

South African pregnant women (n=241) were recruited in the MACE birth cohort study in Durban, a city with high levels of industry and traffic related pollutants. EPHX1 SNPs were genotyped using PCR-RFLP and grouped into their respective phenotypes, i.e. normal (N), slow (S), very slow (VS) and fast (F). EPHX1, miR-26b-5p, miR-193b-3p and miR-1207-5p expression were determined using quantitative PCR.

RESULTS

Mothers with the Tyr113His SNP had low iron levels [TT vs. TC+CC: mean difference (MD)=0.67g/dl; p=0.0167], LBW [TT vs. TC+CC: MD=189.30g; p=0.0067], and low EPHX1 expression; p<0.0001. miR-26b-5p and miR-1207-5p expression were significantly higher in the CC genotypes compared to TT+TC groups; p<0.0001. The opposite trend occurred for miR-193b-3p; p=0.0045. Mothers with the VS phenotype had low iron levels [N vs. VS and VS vs. F: MD=2.03 and -1.96g/dl; p=0.0021, respectively], decreased gestational age [VS vs. F: MD=-2.14weeks; p=0.0051, respectively], and LBW [N vs. VS, VS vs. F and S vs. VS: MD=1000, -940.30 and 968.80g; p<0.0001, respectively]; F phenotype had the highest EPHX1 expression [N vs. F, VS vs. F and S vs. F: MD=-1.067, -1.854 and -1.379; p=0.0002, respectively]; and N phenotype had low miR-26b-5p [N vs. VS: MD=-0.6100; p=0.0159] and miR-1207-5p [N vs. VS and VS vs. F: MD=-0.834 and 1.103; p=0.0007, respectively] expression. miR-193b-3p expression between phenotypes remained unchanged.

CONCLUSION

The Tyr113His T/C variant of rs1051740 and VS phenotype alters EPHX1, miR-26b-5p and miR-1207-5p expression, and contributes towards low blood iron levels and LBW.

The composition of cigarette smoke determines inflammatory cell recruitment to the lung in COPD mouse models

COPD (chronic obstructive pulmonary disease) is caused by exposure to toxic gases and particles, most often CS (cigarette smoke), leading to emphysema, chronic bronchitis, mucus production and a subsequent decline in lung function. The disease pathogenesis is related to an abnormal CS-induced inflammatory response of the lungs. Similar to active (mainstream) smoking, second hand (sidestream) smoke exposure severely affects respiratory health. These processes can be studied in vivo in models of CS exposure of mice. We compared the acute inflammatory response of female C57BL/6 mice exposed to two concentrations [250 and 500 mg/m³ TPM (total particulate matter)] of sidestream and mainstream CS for 3 days and interpreted the biological effects based on physico-chemical differences in the gas and particulate phase composition of CS. BAL (bronchoalveolar lavage fluid) was obtained to perform differential cell counts and to measure cytokine release. Lung tissue was used to determine mRNA and protein expression of proinflammatory genes and to assess tissue inflammation. A strong acute inflammatory response characterized by neutrophilic influx, increased cytokine secretion [KC (keratinocyte chemoattractant), TNF-α (tumour necrosis factor α), MIP-2 (macrophage inflammatory protein 2), MIP-1α and MCP-1 (monocyte chemoattractant protein-1)], pro-inflammatory gene expression [KC, MIP-2 and MMP12 (matrix metalloproteinase 12)] and up-regulated GM-CSF (granulocyte macrophage colony-stimulating factor) production was observed in the mainstream model. After sidestream exposure there was a dampened inflammatory reaction consisting only of macrophages and diminished GM-CSF levels, most likely caused by elevated CO concentrations. These results demonstrate that the composition of CS determines the dynamics of inflammatory cell recruitment in COPD mouse models. Different initial inflammatory processes might contribute to COPD pathogenesis in significantly varying ways, thereby determining the outcome of the studies.

Differential diagnosis for bilateral abnormalities of the basal ganglia and thalamus

The basal ganglia and thalamus are paired deep gray matter structures that may be involved by a wide variety of disease entities. The basal ganglia are highly metabolically active and are symmetrically affected in toxic poisoning, metabolic abnormalities, and neurodegeneration with brain iron accumulation. Both the basal ganglia and thalamus may be affected by other systemic or metabolic disease, degenerative disease, and vascular conditions. Focal flavivirus infections, toxoplasmosis, and primary central nervous system lymphoma may also involve both deep gray matter structures. The thalamus is more typically affected alone by focal conditions than by systemic disease. Radiologists may detect bilateral abnormalities of the basal ganglia and thalamus in different acute and chronic clinical situations, and although magnetic resonance (MR) imaging is the modality of choice for evaluation, the correct diagnosis can be made only by taking all relevant clinical and laboratory information into account. The neuroimaging diagnosis is influenced not only by detection of specific MR imaging features such as restricted diffusion and the presence of hemorrhage, but also by detection of abnormalities involving other parts of the brain, especially the cerebral cortex, brainstem, and white matter. Judicious use of confirmatory neuroimaging investigations, especially diffusion-weighted imaging, MR angiography, MR venography, and MR spectroscopy during the same examination, may help improve characterization of these abnormalities and help narrow the differential diagnosis.

Efficacy and safety of inhaled carbon monoxide during pulmonary inflammation in mice

Background

Pulmonary inflammation is a major contributor to morbidity in a variety of respiratory disorders, but treatment options are limited. Here we investigate the efficacy, safety and mechanism of action of low dose inhaled carbon monoxide (CO) using a mouse model of lipopolysaccharide (LPS)-induced pulmonary inflammation.

Methodology

Mice were exposed to 0–500 ppm inhaled CO for periods of up to 24 hours prior to and following intratracheal instillation of 10 ng LPS. Animals were sacrificed and assessed for intraalveolar neutrophil influx and cytokine levels, flow cytometric determination of neutrophil number and activation in blood, lung and lavage fluid samples, or neutrophil mobilisation from bone marrow.

Principal Findings

When administered for 24 hours both before and after LPS, inhaled CO of 100 ppm or more reduced intraalveolar neutrophil infiltration by 40–50%, although doses above 100 ppm were associated with either high carboxyhemoglobin, weight loss or reduced physical activity. This anti-inflammatory effect of CO did not require pre-exposure before induction of injury. 100 ppm CO exposure attenuated neutrophil sequestration within the pulmonary vasculature as well as LPS-induced neutrophilia at 6 hours after LPS, likely due to abrogation of neutrophil mobilisation from bone marrow. In contrast to such apparently beneficial effects, 100 ppm inhaled CO induced an increase in pulmonary barrier permeability as determined by lavage fluid protein content and translocation of labelled albumin from blood to the alveolar space.

Conclusions

Overall, these data confirm some protective role for inhaled CO during pulmonary inflammation, although this required a dose that produced carboxyhemoglobin values close to potentially toxic levels for humans, and increased lung permeability.

Serum ferritin and transferrin levels as serologic markers of methylene diphenyl diisocyanate-induced occupational asthma

BACKGROUND

Although methylene diphenyl diisocyanate (MDI) may induce occupational asthma in the workplace, the pathogenic mechanisms are unclear.

OBJECTIVES

By using bronchoalveolar lavage fluid, we sought to identify proteins that were differentially expressed between subjects with MDI-induced occupational asthma (MDI-OA) and asymptomatic exposed controls (AECs).

METHODS

To find proteins that were differentially expressed between the MDI-OA and AEC groups, 2-dimensional electrophoresis was performed by using bronchoalveolar lavage fluid obtained from subjects after MDI-specific inhalation challenge. The selected protein spots were then identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The clinical relevance of the differentially expressed spots was compared by ELISA using sera from the MDI-OA/eosinophilic bronchitis, AEC, and unexposed healthy control groups. Receiver operating characteristic curves were then plotted, and the sensitivity and specificity were determined.

RESULTS

Twenty-three protein spots were identified that distinguished the subjects with MDI-OA from those in the AEC group. Among them, ferritin expression was downregulated whereas transferrin expression was upregulated in subjects with MDI-OA compared with AEC; these results were validated by ELISA using sera from the MDI-OA/EB and AEC groups. To identify subjects with MDI-OA, the optimal serum cutoff levels were 69.84 ng/mL for ferritin and 2.48 microg/mL for transferrin. When these 2 parameters were combined, the sensitivity was 71.43% and the specificity was 85.71%.

CONCLUSION

Serum ferritin and transferrin levels are associated with the phenotype of MDI-OA.

Carbon monoxide, reactive oxygen signaling, and oxidative stress

The ubiquitous gas, carbon monoxide (CO), is of substantial biological importance, but apart from its affinity for reduced transition metals, particularly heme-iron, it is surprisingly nonreactive-as is the ferrous-carbonyl-in living systems. CO does form strong complexes with heme proteins for which molecular O2 is the preferred ligand and to which are attributed diverse physiological, adaptive, and toxic effects. Lately, it has become apparent that both exogenous and endogenous CO produced by heme oxygenase engender a prooxidant milieu in aerobic mammalian cells which initiates signaling related to reactive oxygen species (ROS) generation. ROS signaling contingent on CO can be segregated by CO concentration-time effects on cellular function, by the location of heme proteins, e.g., mitochondrial or nonmitochondrial sites, or by specific oxidation-reduction (redox) reactions. The fundamental responses to CO involve overt physiological regulatory events, such as activation of redox-sensitive transcription factors or stress-activated kinases, which institute compensatory expression of antioxidant enzymes and other adaptations to oxidative stress. In contrast, responses originating from highly elevated or protracted CO exposures tend to be nonspecific, produce untoward biological oxidations, and interfere with homeostasis. This brief overview provides a conceptual framework for understanding CO biology in terms of this physiological-pathological hierarchy.