Author Correction: Spatial and temporal heterogeneity of mouse and human microglia at single-cell resolution.

In this Letter, Dominic Grün and Sagar have been added to the author list (affiliated with Max-Planck-Institute of Immunology and Epigenetics (MPI-IE), Freiburg, Germany). The author list, 'Author contribution' and 'Acknowledgements' sections have been corrected online. See accompanying Amendment.

Spatial and temporal heterogeneity of mouse and human microglia at single-cell resolution.

Microglia have critical roles not only in neural development and homeostasis, but also in neurodegenerative and neuroinflammatory diseases of the central nervous system1-4. These highly diverse and specialized functions may be executed by subsets of microglia that already exist in situ, or by specific subsets of microglia that develop from a homogeneous pool of cells on demand. However, little is known about the presence of spatially and temporally restricted subclasses of microglia in the central nervous system during development or disease. Here we combine massively parallel single-cell analysis, single-molecule fluorescence in situ hybridization, advanced immunohistochemistry and computational modelling to comprehensively characterize subclasses of microglia in multiple regions of the central nervous system during development and disease. Single-cell analysis of tissues of the central nervous system during homeostasis in mice revealed specific time- and region-dependent subtypes of microglia. Demyelinating and neurodegenerative diseases evoked context-dependent subtypes of microglia with distinct molecular hallmarks and diverse cellular kinetics. Corresponding clusters of microglia were also identified in healthy human brains, and the brains of patients with multiple sclerosis. Our data provide insights into the endogenous immune system of the central nervous system during development, homeostasis and disease, and may also provide new targets for the treatment of neurodegenerative and neuroinflammatory pathologies.

Development of a quantum cascade laser absorption spectrometer for simultaneous measurement of 13C-18O and 18O-18O clumping in CO2.

RATIONALE: Dual clumped isotope paleothermometry determines carbonate formation temperatures by measuring the frequency of 13C-18O (∆638) and 18O-18O (∆828) pairs in carbonates. It resolves isotopic kinetic biases and thus enables more accurate paleotemperature reconstructions. However, high-precision measurements of 18O-18O clumping using current techniques requires large sample sizes and long acquisition times. METHODS: We developed a mid-infrared isotope ratio laser spectrometer (IRLS) for simultaneous measurement of the isotopologue ratios ∆638 and ∆828 in gas-phase carbon dioxide (CO2) at room temperature. Our IRLS uses a single laser scanning from 2290.7 to 2291.1 cm-1 and a 31 m pathlength optical cell, and it simultaneously measures the five isotopologues required for calculating ∆638 and ∆828: 16O12C16O, 16O13C16O, 16O12C18O, 16O13C18O, and 18O12C18O. In addition, our IRLS can measure 16O12C17O, enabling ∆17O analysis. RESULTS: At ~20°C and a CO2 pressure of ~2 Torr, our IRLS system achieved precisions of 0.128‰ and 0.140‰ within 20 s for abundances of the clumped isotopologues 16O13C18O and 18O12C18O, respectively, and precisions of 0.267‰, 0.245‰, and 0.128‰ for 16O12C16O, 16O13C16O, and 16O12C18O. This yielded precisions of 0.348‰ (∆638) and 0.302‰ (∆828) within 25 s. Simulated sample-reference switching highlights the potential of our system and the need for further development. CONCLUSIONS: We demonstrated simultaneous measurements of ∆638 and ∆828 in CO2 to precisions of <0.35‰ within 25 s using a room-temperature, single-laser IRLS. Future developments on better resolving 16O12C16O and 16O13C16O peaks and system temperature control could further improve the measurement precision.

Small intracranial aneurysms of the anterior circulation: A negligible risk?

BACKGROUND AND PURPOSE: According to the International Study of Unruptured Intracranial Aneurysms, small (<7 mm) unruptured intracranial aneurysms (IAs) of the anterior circulation (aC) carry a neglectable 5-year rupture risk. In contrast, some studies report frequencies of >20% of all ruptured IAs being small IAs of the aC. This contradiction was addressed in this study by analyzing the rates and risk factors for rupture of small IAs within the aC. METHODS: Of the institutional observational cohort, 1676 small IAs of the aC were included. Different demographic, clinical, laboratory, and radiographic characteristics were collected. A rupture risk score was established using all independent prognostic factors. The score performance was checked using receiver operating characteristic curve analysis. RESULTS: Of all registered small IAs of the aC, 20.1% were ruptured. The developed small IAs of the aC (SIAAC) score (range = -4 to +13 points) contained five major risk factors: IA location and size, arterial hypertension, alcohol abuse, and chronic renal failure. In addition, three putative protective factors were also included in the score: hypothyroidism, dyslipidemia, and peripheral arterial disease. Increasing rates of ruptured IA with increasing SIAAC scores were observed, from 0% (≤-1 points) through >50% (≥8 points) and up to 100% in patients scoring ≥12 points. The SIAAC score achieved excellent discrimination (area under the curveSIAAC  = 0.803) and performed better than the PHASES (Population,Hypertension, Age, Size of the aneurysm, Earlier SAH from another aneurysm, Site of aneurysm) score. CONCLUSIONS: Small IAs of the aC carry a considerable rupture risk. After external validation, the proposed rupture risk score might provide a basis for better decision-making regarding the treatment of small unruptured IAs of the aC.

Time interval between the diagnosis of breast cancer and brain metastases impacts prognosis after metastasis surgery.

PURPOSE: Breast cancer (BC) is the most frequently diagnosed tumor entity in women. Occurring at different time intervals (TI) after BC diagnosis, brain metastases (BM) are associated with poor prognosis. We aimed to identify the risk factors related to and the clinical impact of timing on overall survival (OS) after BM surgery. METHODS: We included 93 female patients who underwent BC BM surgery in our institution (2008-2019). Various clinical, radiographic, and histopathologic markers were analyzed with respect to TI and OS. RESULTS: The median TI was 45.0 months (range: 9-334.0 months). Fifteen individuals (16.1%) showed late occurrence of BM (TI ≥ 10 years), which was independently related to invasive lobular BC [adjusted odds ratio (aOR) 9.49, 95% confidence interval (CI) 1.47-61.39, p = 0.018] and adjuvant breast radiation (aOR 0.12, 95% CI 0.02-0.67, p = 0.016). Shorter TI (< 5 years, aOR 4.28, 95% CI 1.46-12.53, p = 0.008) was independently associated with postoperative survival and independently associated with the Union for International Cancer Control stage (UICC) III-IV of BC (aOR 4.82, 95% CI 1.10-21.17, p = 0.037), midline brain shift in preoperative imaging (aOR10.35, 95% CI 1.09-98.33, p = 0.042) and identic estrogen receptor status in BM (aOR 4.56, 95% CI 1.35-15.40, p = 0.015). CONCLUSIONS: Several factors seem to influence the period between BC and BM. Occurrence of BM within five years is independently associated with poorer prognosis after BM surgery. Patients with invasive lobular BC and without adjuvant breast radiation are more likely to develop BM after a long progression-free survival necessitating more prolonged cancer aftercare of these individuals.

Radiographic markers of breast cancer brain metastases: relation to clinical characteristics and postoperative outcome.

OBJECTIVE: Occurrence of brain metastases BM is associated with poor prognosis in patients with breast cancer (BC). Magnetic resonance imaging (MRI) is the standard of care in the diagnosis of BM and determines further treatment strategy. The aim of the present study was to evaluate the association between the radiographic markers of BCBM on MRI with other patients' characteristics and overall survival (OS). METHODS: We included 88 female patients who underwent BCBM surgery in our institution from 2008 to 2019. Data on demographic, clinical, and histopathological characteristics of the patients and postoperative survival were collected from the electronic health records. Radiographic features of BM were assessed upon the preoperative MRI. Univariable and multivariable analyses were performed. RESULTS: The median OS was 17 months. Of all evaluated radiographic markers of BCBM, only the presence of necrosis was independently associated with OS (14.5 vs 22.5 months, p = 0.027). In turn, intra-tumoral necrosis was more often in individuals with shorter time interval between BC and BM diagnosis (< 3 years, p = 0.035) and preoperative leukocytosis (p = 0.022). Moreover, dural affection of BM was more common in individuals with positive human epidermal growth factor receptor 2 status (p = 0.015) and supratentorial BM location (p = 0.024). CONCLUSION: Intra-tumoral necrosis demonstrated significant association with OS after BM surgery in patients with BC. The radiographic pattern of BM on the preoperative MRI depends on certain tumor and clinical characteristics of patients.

Electrolyte and renal disorders in patients with newly diagnosed glioblastoma.

Purpose: Disturbances of electrolytes and renal function have been linked to the prognosis of critically ill patients and recently also of cancer patients. This study aimed to assess electrolyte and renal disorders in glioblastoma patients and evaluate their prognostic effect. Methods: Medical records of patients with newly diagnosed glioblastoma between 2005 and 2018 were retrospectively reviewed for electrolyte and renal function parameters and for demographic, clinical and outcome parameters. Results: Electrolyte and renal function disorders were associated with poorer survival in univariate and Kaplan-Meier analysis. Multivariate analysis revealed hypochloremia as an independent prognostic factor for overall and 1-year survival. Conclusion: Only hypochloremia showed an association with glioblastoma prognosis, independent of other known prognostic factors, as age or molecular status.

Dissolved gas sensing using an anti-resonant hollow core optical fiber.

Sensors that measure dissolved gases directly are needed for environmental, industrial, and biomedical applications. Here we present a hollow core fiber optic sensor capable of measuring dissolved methane gas in liquids using only nanoliters of sample gas. The sensor is based on an anti-resonant hollow core fiber combined with a permeable capillary membrane inlet that extracts gas from the liquid for analysis. Using a small capillary inlet for gas extraction is only possible due to the small amount of sample gas needed for analysis, and it presents new possibilities for dissolved gas analysis in a simple, robust, and compact sensor configuration. We demonstrate the sensing technique using wavelength modulation spectroscopy and measure methane dissolved in water with a 1σ lower detection limit of 230 ppb, a resolution of 45 ppb, and a response time of ∼8min.

Field-Portable Microplastic Sensing in Aqueous Environments: A Perspective on Emerging Techniques.

Microplastics (MPs) have been found in aqueous environments ranging from rural ponds and lakes to the deep ocean. Despite the ubiquity of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. Although standards exist for MP sample collection and preparation, methods of MP analysis vary considerably and produce data with a broad range of data content and quality. The need for extensive analysis-specific sample preparation in current technology approaches has hindered the emergence of a single technique which can operate on aqueous samples in the field, rather than on dried laboratory preparations. In this perspective, we consider MP measurement technologies with a focus on both their eventual field-deployability and their respective data products (e.g., MP particle count, size, and/or polymer type). We present preliminary demonstrations of several prospective MP measurement techniques, with an eye towards developing a solution or solutions that can transition from the laboratory to the field. Specifically, experimental results are presented from multiple prototype systems that measure various physical properties of MPs: pyrolysis-differential mobility spectroscopy, short-wave infrared imaging, aqueous Nile Red labeling and counting, acoustophoresis, ultrasound, impedance spectroscopy, and dielectrophoresis.

Quantum cascade laser-based reflectance spectroscopy: a robust approach for the classification of plastic type.

The identification of plastic type is important for environmental applications ranging from recycling to understanding the fate of plastics in marine, atmospheric, and terrestrial environments. Infrared reflectance spectroscopy is a powerful approach for plastics identification, requiring only optical access to a sample. The use of visible and near-infrared wavelengths for plastics identification are limiting as dark colored plastics absorb at these wavelengths, producing no reflectance spectra. The use of mid-infrared wavelengths instead enables dark plastics to be identified. Here we demonstrate the capability to utilize a pulsed, widely-tunable (5.59 - 7.41 µm) mid-infrared quantum cascade laser, as the source for reflectance spectroscopy, for the rapid and robust identification of plastics. Through the application of linear discriminant analysis to the resulting spectral data set, we demonstrate that we can correctly classify five plastic types: polyethylene terephthalate (PET), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS), with a 97% accuracy rate.

Rapid Identification of Marine Plastic Debris via Spectroscopic Techniques and Machine Learning Classifiers.

To advance our understanding of the environmental fate and transport of macro- and micro-plastic debris, robust and reproducible methods, technologies, and analytical approaches are necessary for in situ plastic-type identification and characterization. This investigation compares four spectroscopic techniques: attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), near-infrared (NIR) reflectance spectroscopy, laser-induced breakdown spectroscopy (LIBS), and X-ray fluorescence (XRF) spectroscopy, coupled to seven classification methods, including machine learning classifiers, to determine accuracy for identifying type of both consumer plastics and marine plastic debris (MPD). With machine learning classifiers, consumer plastic types were identified with 99, 91, 97, and 70% success rates for ATR-FTIR, NIR reflectance spectroscopy, LIBS, and XRF, respectively. The classification of MPD had similar or lower success rates, likely arising from alterations to the plastic from environmental weathering processes with success rates of 99, 81, 76, and 66% for ATR-FTIR, NIR reflectance spectroscopy, LIBS, and XRF, respectively. Success rates indicate that ATR-FTIR, NIR reflectance spectroscopy, and LIBS coupled with machine learning classifiers can be used to identify both consumer and environmental plastic samples.

Rapid Mapping of Dissolved Methane and Carbon Dioxide in Coastal Ecosystems Using the ChemYak Autonomous Surface Vehicle.

Coastal ecosystems host high levels of primary productivity leading to exceptionally dynamic elemental cycling in both water and sediments. In such environments, carbon is rapidly cycled leading to high rates of burial as organic matter and/or high rates of loss to the atmosphere and laterally to the coastal ocean in simpler forms, such as carbon dioxide (CO2) and methane (CH4). To better understand carbon cycling across these heterogeneous environments, new technologies beyond discrete sample collection and analysis are needed to characterize spatial and temporal variability. Here, we describe the ChemYak, an autonomous surface vehicle outfitted with a suite of in situ sensors, developed to achieve large spatial scale chemical mapping of these environments. Dissolved methane and carbon dioxide are measured by a laser spectrometer coupled to a gas extraction unit for continuous quantification during operation. The gas-powered vehicle is capable of rapidly surveying the coastal system with an endurance of up to 10 h at operating speeds in excess of 10 km h-1. Here, we demonstrate its ability to spatially characterize distributions of CO2, CH4, oxygen, and nitrate throughout a New England saltmarsh estuary.

Open-path spectroscopic methane detection using a broadband monolithic distributed feedback-quantum cascade laser array.

Methane is a powerful greenhouse gas that has both natural and anthropogenic sources. The ability to measure methane using an integrated path length approach such as an open/long-path length sensor would be beneficial in several environments for examining anthropogenic and natural sources, including tundra landscapes, rivers, lakes, landfills, estuaries, fracking sites, pipelines, and agricultural sites. Here a broadband monolithic distributed feedback-quantum cascade laser array was utilized as the source for an open-path methane sensor. Two telescopes were utilized for the launch (laser source) and receiver (detector) in a bistatic configuration for methane sensing across a 50 m path length. Direct-absorption spectroscopy was utilized with intrapulse tuning. Ambient methane levels were detectable, and an instrument precision of 70 ppb with 100 s averaging and 90 ppb with 10 s averaging was achieved. The sensor system was designed to work "off the grid" and utilizes batteries that are rechargeable with solar panels and wind turbines.

Lactose-functionalized dendrimers arbitrate the interaction of galectin-3/MUC1 mediated cancer cellular aggregation.

By using lactose-functionalized poly(amidoamine) dendrimers as a tunable multivalent platform, we studied cancer cell aggregation in three different cell lines (A549, DU-145, and HT-1080) with galectin-3. We found that small lactose-functionalized G(2)-dendrimer 1 inhibited galectin-3-induced aggregation of the cancer cells. In contrast, dendrimer 4 (a larger, generation 6 dendrimer with 100 carbohydrate end groups) caused cancer cells to aggregate through a galectin-3 pathway. This study indicates that inhibition of cellular aggregation occurred because 1 provided competitive binding sites for galectin-3 (compared to its putative cancer cell ligand, TF-antigen on MUC1). Dendrimer 4, in contrast, provided an excess of ligands for galectin-3 binding; this caused crosslinking and aggregation of cells to be increased.

Multivalent scaffolds induce galectin-3 aggregation into nanoparticles.

Galectin-3 meditates cell surface glycoprotein clustering, cross linking, and lattice formation. In cancer biology, galectin-3 has been reported to play a role in aggregation processes that lead to tumor embolization and survival. Here, we show that lactose-functionalized dendrimers interact with galectin-3 in a multivalent fashion to form aggregates. The glycodendrimer-galectin aggregates were characterized by dynamic light scattering and fluorescence microscopy methodologies and were found to be discrete particles that increased in size as the dendrimer generation was increased. These results show that nucleated aggregation of galectin-3 can be regulated by the nucleating polymer and provide insights that improve the general understanding of the binding and function of sugar-binding proteins.

Longitudinal impact of intracerebral low-grade glioma disease on health-related quality of life.

BACKGROUND: The aim of this study was to assess health-related quality of life (HRQOL) before and after treatment for intracerebral low-grade glioma. METHODS: Patients with low-grade glioma who underwent surgical tumor removal between 2012 and 2018 were eligible for this study. All individuals and their closest relatives received thorough preoperative (

Reevaluation of risk factors for aneurysmal subarachnoid hemorrhage associated epilepsy.

BACKGROUND: Symptomatic epilepsy is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) associated with poor outcome. We sought to analyze the risk factors leading to post-SAH epilepsy. METHODS: All consecutive aSAH cases treated between 01/2003 and 06/2016 were retrospectively included. Post-aSAH period was followed up to 03/2020 for the occurrence of epilepsy. Demographic characteristics and previous medical history of the patients, parameters of initial severity, performed treatments, certain early and late complications of aSAH, as well as routine laboratory and vital parameter measurements were collected. Functional outcome was assessed at discharge and 6 months after aSAH using the modified Rankin scale (mRS). RESULTS: During the post-aSAH follow-up (median: 8.93 months/patient), 85 of 948 individuals (9%) in the final analysis developed symptomatic epilepsy (median: 3.43 months). In the majority of cases, epilepsy was diagnosed >3 weeks after aSAH (n = 67, 78.8%) and in survivors with poor outcome at discharge (mRS = 4-5, 15.8% vs. 5.3%, p < 0.0001). Of over 150 analyzed potential risk factors, the following parameters were independently associated with the risk of symptomatic epilepsy after aSAH: thyroid dysfunction (aHR = 1.81, p = 0.029), need for decompressive craniectomy (aHR = 2.32, p = 0.011) and shunt placement (aHR = 1.94, p = 0.022), prolonged tachycardia (≥4 days, aHR = 2.06, p = 0.025), as well as anemia signs (mean red blood cell count <3.6 × 1012 /L [aHR = 2.4, p = 0.015] and mean hematocrit <31% [aHR = 2.13, p = 0.044]) during first 2 weeks after aSAH. CONCLUSION: Symptomatic epilepsy occurs predominantly in individuals with poor outcome at discharge and after the acute phase of aSAH. Knowledge of risk factors associated with aSAH-related epilepsy might help in early identification and treatment of compromised individuals, and therefore, help to improve their outcome.

Impact of Treatment Timing on the Risk of Cerebral Infarction in Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Cerebral infarction is a major contributor to poor outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). Timing of treatment has been discussed as a possible contributor. We aimed to analyze the impact of treatment timing on the risk of cerebral infarction and poor outcome after aSAH. METHODS: Consecutive cases of patients with aSAH treated at our institution between January 2003 and June 2016 were included. The cohort was divided into 2 groups, depending on the treatment during (day 4-14 after ictus) or beyond the vasospasm phase. Statistical assessment included a 1:1 propensity score matching analysis and multivariable logistic regression analysis within the whole cohort. RESULTS: Of 943 patients with aSAH, 111 underwent treatment in the vasospasm phase. In the propensity score matching analysis, patients treated during the vasospasm phase were at higher risk of vasospasm requiring intra-arterial spasmolysis (P < 0.0001), cerebral infarction distal to the treated vessel (P < 0.0001), and poor outcome (modified Rankin Scale score >2) at 6 months follow-up (P = 0.025). In the multivariable analysis, aneurysm treatment in the vasospasm phase was independently associated with higher risk of cerebral vasospasm necessitating intra-arterial spasmolysis (P < 0.0001; adjusted odds ratio [aOR], 3.62), cerebral infarction distal to the treated aneurysm (P = 0.01; aOR, 2.02), and poor outcome (P = 0.03; aOR, 2.05). CONCLUSIONS: Our data confirm a considerable risk of cerebral infarction and poor outcome in cases of aneurysm treatment between day 4 and 14 after aSAH. A more intense surveillance and prophylactic treatment of cerebral vasospasm might be necessary in cases of aneurysm treatment in the vasospasm phase.

A New Subform? Fast-Progressing, Severe Neurological Deterioration Caused by Spinal Epidural Lipomatosis.

Spinal epidural lipomatosis (SEL) is a rare condition caused by hypertrophic growth of epidural fat. The prevalence of SEL in the Western world is approximately 1 in 40 patients and is likely to increase due to current medical and socio-economic developments. Rarely, SEL can lead to rapid severe neurological deterioration. The pathophysiology, optimal treatment, and outcome of these patients remain unclear. This study aims to widen current knowledge about this "SEL subform" and to improve its clinical management. A systematic literature review according to the PRISMA guidelines using PubMed, Scopus, Web of Science, and Cochrane Library was used to identify publications before 7 November 2021 reporting on acute/rapidly progressing, severe SEL. The final analysis comprised 12 patients with acute, severe SEL. The majority of the patients were male (9/12) and multimorbid (10/12). SEL mainly affected the thoracic part of the spinal cord (11/12), extending a median number of 7 spinal levels (range: 4-19). Surgery was the only chosen therapy (11/12), except for one critically ill patient. Regarding the outcome, half of the patients regained independence (6/11; = modified McCormick Scale ≤ II). Acute, severe SEL is a rare condition, mainly affecting multimorbid patients. The prognosis is poor in nearly 50% of the patients, even with maximum therapy. Further research is needed to stratify patients for conservative or surgical treatment.