Magnetic Resonance Imaging Reveals Significantly Increased Cerebral Blood Flow in the Hemoglobin E Mouse Model

Hemoglobin E (HbE) is the most common hemoglobin mutation world-wide. EE individuals exhibit a mild anemia as do those with β-thalassemia trait. A paradox arises with the combination of two relatively benign genes in HbE/β-thalassemia (HbE/β-thal) giving rise to highly morbid symptoms, anemia, growth retardation, developmental retardation, thalassemic bone type development, chronic leg ulcers (for a review, S Fucharoen and DJ Weatherall 2012) and often early mortality arising from cardiac failure (N Olivieri, Z Pakbaz et al. 2011). One approach to understanding the characteristics of HbE and this paradox was to generate a transgenic mouse model, expressing solely human HbE. This HbE mouse model exhibits a mild oxidative stress that parallels that observed in human EE individuals (QY Chen, EE Bouhassira et al. 2004, QY Chen, ME Fabry et al. 2012). These transgenic mice also exhibit mild cardiac dysfunction with depressed left ventricular contraction. We present here the first evidence of a significant increase in cerebral blood flow in the full knockout HbE (HbEKO) transgenic mouse model expressing solely human HbE compared to both the HbE+HbF (γ, gamma)-globin transgenic mouse, and the normal background C57 mouse. Cerebral blood flow is assessed non-invasively by MRI imaging. All protocols were approved by the Albert Einstein Institutional Animal Care and Use Committee. Comparing the HbEKO mouse (without human γ globin) to the C57 normal background mouse, a significant increase of over 20% in thalamus cerebral blood flow at baseline is observed (p=0.008). There is also an approximate 18% reduction in thalamus cerebral blood flow comparing HbE low γ mice to the full HbEKO (no γ) (p=0.011). Concomitant with these observations, no significant difference is observed comparing these low gamma HbE mice to the normal C57 background mouse (p=0.384). The goodness of the data is also seen in the relatively small variation in cerebral blood flow amongst the individual mice in each subset. These findings are of particular relevance to reports of neurologic symptoms, intracerebral hemorrhage, and brain infarct in HbE/β-thal patients (V Wong, YL Yu et al. 1990, S Das, S Dubey et al. 2019). In conclusion, these results suggest a direct role of HbE RBC initiating altered cerebral blood flow that when further complexed with β-thal could lead to intracerebral hemorrhage and other cerebral pathophysiology. The finding that the HbEKO mice with high HbF are not significantly different in cerebral blood flow from C57 mice may lend further support to therapeutic approaches enhancing the production of HbF in severe hemoglobinopathies, such as in sickle cell anemia, HbE/β-thal, and β-thal individuals. Disclosures No relevant conflicts of interest to declare.

World on Fire

We face three epoch-defining environmental problems: climate, extinction, and pestilence. Our climate is changing in ways that will have serious consequences for humans, and it may even profoundly affect the ability of the planet to support life. All around us, other species are disappearing at a rate between several hundred and several thousand times the normal background rate of extinction. The SARS-CoV-2 virus, which has wreaked social and economic havoc, is merely the latest model off a blossoming production line of newly emerging infectious diseases, many of which have the potential to be far worse. At the heart of these problems lies an ancient habit: eating animals. This habit is the most significant driver of species extinction and of newly emerging infectious diseases, and one of the most important drivers of climate change. This is a habit we can no longer afford to indulge. Breaking it will substantially reduce climate emissions. It will stem our insatiable hunger for land that is at the heart of both the problems of extinction and pestilence. Most importantly, breaking this habit will make available vast areas of land suitable for afforestation: the return of forests to where they once grew. Afforestation will significantly mitigate all three problems. But only if we stop eating animals will we have enough land for this strategy to work.

The Great Dying

The benefits of no longer eating animals extend beyond climate mitigation. It will also mitigate current species extinction trajectories. This chapter looks at the history of human-caused extinctions. A great extinction occurs when a percentage of a species dies out (e.g., 75%). A mass extinction occurs when the actual rate of extinction exceeds the normal background rate by a certain margin (e.g., 1000×). There are good reasons for thinking that a mass extinction of species is currently occurring. Humans are the cause of this, as they have been the cause of all major extinction pulses since the Quaternary period. This chapter examines one of the Quaternary extinction pulses of 8000–11,500 years ago and defends the hominin paleobiogeography hypothesis, that is, that humans were substantially responsible for this pulse of extinctions. An undue focus on extinction, however, can mask the harm we are currently doing to species.

Hyperspectral Ophthalmoscope Images for the Diagnosis of Diabetic Retinopathy Stage

A methodology that applies hyperspectral imaging (HSI) on ophthalmoscope images to identify diabetic retinopathy (DR) stage is demonstrated. First, an algorithm for HSI image analysis is applied to the average reflectance spectra of simulated arteries and veins in ophthalmoscope images. Second, the average simulated spectra are categorized by using a principal component analysis (PCA) score plot. Third, Beer-Lambert law is applied to calculate vessel oxygen saturation in the ophthalmoscope images, and oxygenation maps are obtained. The average reflectance spectra and PCA results indicate that average reflectance changes with the deterioration of DR. The G-channel gradually decreases because of vascular disease, whereas the R-channel gradually increases with oxygen saturation in the vessels. As DR deteriorates, the oxygen utilization of retinal tissues gradually decreases, and thus oxygen saturation in the veins gradually increases. The sensitivity of diagnosis is based on the severity of retinopathy due to diabetes. Normal, background DR (BDR), pre-proliferative DR (PPDR), and proliferative DR (PDR) are arranged in order of 90.00%, 81.13%, 87.75%, and 93.75%, respectively; the accuracy is 90%, 86%, 86%, 90%, respectively. The F1-scores are 90% (Normal), 83.49% (BDR), 86.86% (PPDR), and 91.83% (PDR), and the accuracy rates are 95%, 91.5%, 93.5%, and 96%, respectively.

Assessment of 5-methylcytosine and 5-hydroxymethylcytosine technologies in contrived ctDNA-like samples.

e15585 Background: Epigenomic changes to DNA are early driving events in tumorigenesis and are specific markers of the tumour and its microenvironment. Cell-free DNA that is released from the tumour microenvironment can potentially be used for the detection of tumour-specific epigenomic changes for cancer liquid biopsy testing. In this study, we assessed the robustness of 5-methylcytosine and 5-hydroxymethylcytosine technologies in contrived ctDNA-like samples from NSCLC. Additionally, we assessed the limit of detection of the tumour fraction within the tested dilution range looking at a subset of differential epigenomic marks. Methods: 4 NSCLC tumour and buffy coat DNA samples were commercially obtained and processed to generate contrived tumour DNA dilution mimicking circulating tumour DNA at varying tumour fractions. Samples were sent in triplicate to multiple epigenomic assay providers for analysis. The robustness i.e. reproducibility and limit-of-detection within the tested range was determined. Results: Technical replicates all passed method-specific quality controls and were highly reproducible. Cancer specific differentially-methylated or hydroxymethylated regions were determined for each individual tumour sample as a “sample-specific cancer signature”; when applied to the tumour dilution samples, these signatures were capable of distinguishing all tumour dilutions down to 0.05% from normal background DNA. Detection of differential methylation and hydroxymethylation regions was reproducible across technical replicates for all four NCSLC samples at > 0.05%. Generation of pooled methylation “signatures” derived from commercially available healthy plasma and cancer tissue datasets could still detect cancer DNA in these four NCSLC samples at > 0.1% tumour fraction. Conclusions: Our pilot study showed that all assessed technologies generated reproducible, robust data and could detect ctDNA at even clinically relevant levels for early stage cancer. One limitation of this study was the small number of “n” and the use of sonicated contrived sample that may induce artificial bias and reduce sensitivity highlighting a requirement for the development of reference material in the community. The ability to detect cancer-specific epigenomic changes from liquid biopsy with high sensitivity offers new promising avenues for early detection of cancer, which can increase the chances of successful treatment.

Toxic mercury pulses into late Permian terrestrial and marine environments

Large spikes in mercury (Hg) concentration are observed globally at the latest Permian extinction (LPE) horizon that are thought to be related to enhanced volcanic emissions of the Siberian Traps large igneous province (LIP). While forming an effective chemostratigraphic marker, it remains unclear whether such enhanced volcanic Hg emissions could have generated toxic conditions that contributed to extinction processes. To address this, we examined the nature of enhanced Hg emissions from the Siberian Traps LIP and the potential impact it may have had on global ecosystems during the LPE. Model results for a LIP eruption predict that pulses of Hg emissions to the atmosphere would have been orders of magnitude greater than normal background conditions. When deposited into world environments, this would have generated a series of toxic shocks, each lasting >1000 yr. Such repeated Hg loading events would have had severe impact across marine trophic levels, as well as been toxic to terrestrial plant and animal life. Such high Hg loading rates may help explain the co-occurrence of marine and terrestrial extinctions.

Reading Epilepsy—An Interesting Case Report

Reading epilepsy is a language induced reflex epilepsy with common ictal manifestations of regional myoclonus. The electroencephalogram (EEG) often shows focal, regional, or generalized discharges, rarely there may not be any associated EEG changes. We report case of a 25-year-old male with three episodes of seizures, precipitated while reading a book. Reported semiology was stuttering while reading with jerking of tongue as perceived by the patient followed by generalized tonic–clonic seizures (GTCS). Magnetic resonance imaging (MRI) of brain with 3 Tesla (3T) was normal. During videoelectroencephalogram (vEEG), reading precipitated recurrent stuttering each lasting for 1 to 2 seconds. Corresponding vEEG showed rhythmic 1/second symmetrical generalized spike and wave discharges lasting for 2 to 4 seconds during episodes of stuttering with intervening normal background activity, followed by generalized spike and wave discharges intermixed with artifacts recorded during secondary generalization. Patient was prescribed levetiracetam and responded well and is currently seizure-free for more than 6 years.

Prediction of regaining consciousness despite an early epileptiform EEG after cardiac arrest

ObjectiveAfter cardiac arrest (CA), epileptiform EEG, occurring in about 1/3 of patients, often but not invariably heralds poor prognosis. We tested the hypothesis that a combination of specific EEG features identifies patients who may regain consciousness despite early epileptiform patterns.MethodsWe retrospectively analyzed a registry of comatose patients post-CA (2 Swiss centers), including those with epileptiform EEG. Background and epileptiform features in EEGs 12–36 hours or 36–72 hours from CA were scored according to the American Clinical Neurophysiology Society nomenclature. Best Cerebral Performance Category (CPC) score within 3 months (CPC 1–3 vs 4–5) was the primary outcome. Significant EEG variables were combined in a score assessed with receiver operating characteristic curves, and independently validated in a US cohort; its correlation with serum neuron-specific enolase (NSE) was also tested.ResultsOf 488 patients, 107 (21.9%) had epileptiform EEG <72 hours; 18 (17%) reached CPC 1–3. EEG 12–36 hours background continuity ≥50%, absence of epileptiform abnormalities (p < 0.00001 each), 12–36 and 36–72 hours reactivity (p < 0.0001 each), 36–72 hours normal background amplitude (p = 0.0004), and stimulus-induced discharges (p = 0.0001) correlated with favorable outcome. The combined 6-point score cutoff ≥2 was 100% sensitive (95% confidence interval [CI], 78%–100%) and 70% specific (95% CI, 59%–80%) for CPC 1–3 (area under the curve [AUC], 0.98; 95% CI, 0.94–1.00). Increasing score correlated with NSE (ρ = −0.46, p = 0.0001). In the validation cohort (41 patients), the score was 100% sensitive (95% CI, 60%–100%) and 88% specific (95% CI, 73%–97%) for CPC 1–3 (AUC, 0.96; 95% CI, 0.91–1.00).ConclusionPrognostic value of early epileptiform EEG after CA can be estimated combining timing, continuity, reactivity, and amplitude features in a score that correlates with neuronal damage.

Normal background levels of air and surface mould reserve in English residential building stock: a preliminary study towards benchmarks based on NAHA measurements

This paper reports results obtained from a surface (both visually clean and dirty/dusty surfaces) and active (aggressive or activated) air testing scheme on 140 residential rooms in England, without visible water damage or mould growth, along with a few rooms with visible mould growth/water damage tested for comparison purposes. The aim was to establish normal background levels of mould in non-water-damaged interiors to benchmark a ‘normal’ indoor environment, and in turn when there is a need for further investigation, and, possibly, remediation. Air and surface mould was quantified based on the activity of β-N-acetylhexosaminidase (EC 3.2.1.52; NAHA). The obtained readings showed a log-normal distribution. Ninety-eight percent of the samples obtained from visually clean surfaces were equal to or less than 25 relative fluorescence units (RFU), which is suggested to be the higher bound for the range which can be used as a success criterion for surface cleaning/remediation. Of samples obtained from visually dirty/dusty surfaces, around 98% were below 450 RFU, which is suggested to define the lower-bound for abnormally high levels of mould, rare even on dirty/dusty surfaces. Similarly, around 98% of the air samples were found to have 1700 RFU or below. Values above 1700 RFU are therefore deemed unlikely in a non-problem indoor environment and can be indicative of a possible problem inducing mould growth. The samples with values below 1700 were further divided into three proposed sub-categories. Finally, the obtained RFU values and the suggested benchmarks were compared to those obtained from 17 non-residential indoor environments tested previously in Copenhagen, and the benchmarks that are currently used in Danish national standards, and they were both found to be highly congruent, suggesting that local climate regimes and room functions might not be as influential on indoor mould levels as commonly thought, or that the nuances between England and Denmark in terms of these factors are not strong enough to lead to sizable changes in the typical indoor mould levels in these countries’ building stocks.