Laser Mass Spectrometry Research Articles

Generation and Analysis of Tritium-Substituted Methane

An unavoidable category of molecular species in large-scale tritium applications, such as nuclear fusion, are tritium-substituted hydrocarbons, which form by radiochemical reactions in the presence of (circulating) tritium and carbon (mainly from the steel of vessels and tubing). Tritium-substituted methane species, CQ4 (with Q = H,D,T), are often the precursor for higher-order reaction chains, and thus are of particular interest. Here we describe the controlled production of CQ4 carried out in the CAPER facility of the Tritium Laboratory Karlsruhe, exploiting catalytic reactions and species enrichment via the CAPER integral permeator. CQ4 was generated in substantial quantities (>1000 cm3 at ~850 mbar, with CQ4content of up to ~20%). The samples were analyzed using laser Raman and mass spectrometry to determine the relative isotopologue composition and to trace the generation of tritiated chain hydrocarbons.

Investigation on the influence of high rate cooling crystallization process (HRCCP) parameters on the preparation and thermal behavior of ammonium perchlorate particles using Taguchi method

The preparation of fine ammonium perchlorate (AP) particles and its thermal behavior are the most important properties in propellants. In this study, the effects of temperature, pressure, solvent type (water and ethanol), and anticaking agent- sodium dodecyl sulfate (SDS) were investigated on the AP particles using the Taguchi approach in high-rate cooling crystallization process (HRCCP). The average particle size (APS) of AP particles was calculated using laser mass spectrometry (LMS-30). The results showed that the anti-caking agent and solvent type were represented the main effect on the preparation of micronized AP particles, based on analysis of variance. Furthermore, the optimum condition was ethanol solvent, 10 atm pressure, 0.4% SDS, and 60 °C temperature. Also, the thermal behavior of the optimized particles was investigated using TG/DSC analysis.

AHNAK, regulated by the OSM/OSMR signaling, involved in the development of primary localized cutaneous amyloidosis

BackgroundPrimary localized cutaneous amyloidosis (PLCA) is a chronic skin disease characterized by aberrant keratinocyte differentiation, epidermal hyperproliferation, and amyloid deposits. Previously, we demonstrated OSMR loss-function mutants enhanced basal keratinocyte differentiation through the OSMR/STAT5/KLF7 signaling in PLCA patients. ObjectiveTo investigate the underlying mechanisms involved in basal keratinocyte proliferation in PLCA patients that remain unclear. MethodsPatients with pathologically confirmed PLCA visiting the dermatologic outpatient clinic were involved in the study. Laser capture microdissection and mass spectrometry analysis, gene-edited mice, 3D human epidermis culture, flow cytometry, western blot, qRT-PCR and RNA sequencing were used to explore the underlying molecular mechanisms. ResultsIn this study, we found that AHNAK peptide fragments were enriched in the lesions of PLCA patients, as detected by laser capture microdissection and mass spectrometry analysis. The upregulated expression of AHNAK was further confirmed using immunohistochemical staining. qRT-PCR and flow cytometry revealed that pre-treatment with OSM can inhibit AHNAK expression in HaCaT cells, NHEKs, and 3D human skin models, but OSMR knockout or OSMR mutations abolished this down-regulation trend. Similar results were obtained in wild-type and OSMR knockout mice. More importantly, EdU incorporation and FACS assays demonstrated the knockdown of AHNAK could induce G1 phase cell cycle arrest and inhibit keratinocyte proliferation. Furthermore, RNA sequencing revealed that AHNAK knockdown regulated keratinocyte differentiation. ConclusionTaken together, these data indicated that the elevated expression of AHNAK by OSMR mutations led to hyperproliferation and overdifferentiation of keratinocytes, and the discovered mechanism might provide insights into potential therapeutic targets for PLCA.

Probe-based mass spectrometry approaches for single-cell and single-organelle measurements.

Exploring the chemical content of individual cells not only reveals underlying cell-to-cell chemical heterogeneity but is also a key component in understanding how cells combine to form emergent properties of cellular networks and tissues. Recent technological advances in many analytical techniques including mass spectrometry (MS) have improved instrumental limits of detection and laser/ion probe dimensions, allowing the analysis of micron and submicron sized areas. In the case of MS, these improvements combined with MS's broad analyte detection capabilities have enabled the rise of single-cell and single-organelle chemical characterization. As the chemical coverage and throughput of single-cell measurements increase, more advanced statistical and data analysis methods have aided in data visualization and interpretation. This review focuses on secondary ion MS and matrix-assisted laser desorption/ionization MS approaches for single-cell and single-organelle characterization, which is followed by advances in mass spectral data visualization and analysis.

Dynamic Association of ESCRT-II Proteins with ESCRT-I and ESCRT-III Complexes during Phagocytosis of Entamoeba histolytica.

By their active movement and voraux phagocytosis, the trophozoites of Entamoeba histolytica constitute an excellent system to investigate the dynamics of the Endosomal Sorting Complex Required for Transport (ESCRT) protein interactions through phagocytosis. Here, we studied the proteins forming the E. histolytica ESCRT-II complex and their relationship with other phagocytosis-involved molecules. Bioinformatics analysis predicted that EhVps22, EhVps25, and EhVps36 are E. histolytica bona fide orthologues of the ESCRT-II protein families. Recombinant proteins and specific antibodies revealed that ESCRT-II proteins interact with each other, with other ESCRT proteins, and phagocytosis-involved molecules, such as the adhesin (EhADH). Laser confocal microscopy, pull-down assays, and mass spectrometry analysis disclosed that during phagocytosis, ESCRT-II accompanies the red blood cells (RBCs) from their attachment to the trophozoites until their arrival to multivesicular bodies (MVBs), changing their interactive patterns according to the time and place of the process. Knocked-down trophozoites in the Ehvps25 gene presented a 50% lower rate of phagocytosis than the controls and lower efficiency to adhere RBCs. In conclusion, ESCRT-II interacts with other molecules during prey contact and conduction throughout the phagocytic channel and trophozoites membranous system. ESCRT-II proteins are members of the protein chain during vesicle trafficking and are fundamental for the continuity and efficiency of phagocytosis.

A combinatorial droplet microfluidic device integrated with mass spectrometry for enzyme screening.

Mass spectrometry (MS) enables detection of different chemical species with a very high specificity; however, it can be limited by its throughput. Integrating MS with microfluidics has a tremendous potential to improve throughput and accelerate biochemical research. In this work, we introduce Drop-NIMS, a combination of a passive droplet loading microfluidic device and a matrix-free MS laser desorption ionization technique called nanostructure-initiator mass spectrometry (NIMS). This platform combines different droplets at random to generate a combinatorial library of enzymatic reactions that are deposited directly on the NIMS surface without requiring additional sample handling. The enzyme reaction products are then detected with MS. Drop-NIMS was used to rapidly screen enzymatic reactions containing low (on the order of nL) volumes of glycoside reactants and glycoside hydrolase enzymes per reaction. MS "barcodes" (small compounds with unique masses) were added to the droplets to identify different combinations of substrates and enzymes created by the device. We assigned xylanase activities to several putative glycoside hydrolases, making them relevant to food and biofuel industrial applications. Overall, Drop-NIMS is simple to fabricate, assemble, and operate and it has potential to be used with many other small molecule metabolites.

Increasing quantitation in spatial single-cell metabolomics by using fluorescence as ground truth.

Imaging mass spectrometry (MS) is becoming increasingly applied for single-cell analyses. Multiple methods for imaging MS-based single-cell metabolomics were proposed, including our recent method SpaceM. An important step in imaging MS-based single-cell metabolomics is the assignment of MS intensities from individual pixels to single cells. In this process, referred to as pixel-cell deconvolution, the MS intensities of regions sampled by the imaging MS laser are assigned to the segmented single cells. The complexity of the contributions from multiple cells and the background, as well as lack of full understanding of how input from molecularly-heterogeneous areas translates into mass spectrometry intensities make the cell-pixel deconvolution a challenging problem. Here, we propose a novel approach to evaluate pixel-cell deconvolution methods by using a molecule detectable both by mass spectrometry and fluorescent microscopy, namely fluorescein diacetate (FDA). FDA is a cell-permeable small molecule that becomes fluorescent after internalisation in the cell and subsequent cleavage of the acetate groups. Intracellular fluorescein can be easily imaged using fluorescence microscopy. Additionally, it is detectable by matrix-assisted laser desorption/ionisation (MALDI) imaging MS. The key idea of our approach is to use the fluorescent levels of fluorescein as the ground truth to evaluate the impact of using various pixel-cell deconvolution methods onto single-cell fluorescein intensities obtained by the SpaceM method. Following this approach, we evaluated multiple pixel-cell deconvolution methods, the 'weighted average' method originally proposed in the SpaceM method as well as the novel 'linear inverse modelling' method. Despite the potential of the latter method in resolving contributions from individual cells, this method was outperformed by the weighted average approach. Using the ground truth approach, we demonstrate the extent of the ion suppression effect which considerably worsens the pixel-cell deconvolution quality. For compensating the ion suppression individually for each analyte, we propose a novel data-driven approach. We show that compensating the ion suppression effect in a single-cell metabolomics dataset of co-cultured HeLa and NIH3T3 cells considerably improved the separation between both cell types. Finally, using the same ground truth, we evaluate the impact of drop-outs in the measurements and discuss the optimal filtering parameters of SpaceM processing steps before pixel-cell deconvolution.

440 The Proteome of microdissected nevi- and melanoma cells reveal upregulation of Hippo-YAP and PI3K-mTOR pathway

A substantial part of cutaneous malignant melanomas develops from benign nevi. While the mutational landscape of melanoma has been investigated in recent years, the molecular events leading to the malignant transformation remain less characterized. To explore these processes on a proteomic level, we created a cohort of melanomas (N=166) and identified malignant melanomas with a nevi remnant in the same specimen (N=14). We applied a combination of laser microdissection and mass spectrometry based proteomic analysis of nevi melanocytes and melanomas.

Picosecond Infrared Laser Mass Spectrometry Identifies a Metabolite Array for 10 s Diagnosis of Select Skin Cancer Types: A Proof-of-Concept Feasibility Study.

Currently, a large number of skin biopsies are taken for each true skin cancer case detected, creating a need for a rapid, high sensitivity, and specificity skin cancer detection tool to reduce the number of unnecessary biopsies taken from benign tissue. Picosecond infrared laser mass spectrometry (PIRL-MS) using a hand-held sampling probe is reported to detect and classify melanoma, squamous cell carcinoma, and normal skin with average sensitivity and specificity values of 86-95% and 91-98%, respectively (at a 95% confidence level) solely requiring 10 s or less of total data collection and analysis time. Classifications are not adversely affected by specimen's quantity of melanin pigments and are mediated by a number of metabolic lipids, further identified herein as potential biomarkers for skin cancer-type differentiation, 19 of which were sufficient here (as a fully characterized metabolite array) to provide high specificity and sensitivity classification of skin cancer types. In situ detection was demonstrated in an intradermal melanoma mouse model wherein in vivo sampling did not cause significant discomfort. PIRL-MS sampling is further shown to be compatible with downstream gross histopathologic evaluations despite loss of tissue from the immediate laser sampling site(s) and can be configured using selective laser pulses to avoid thermal damage to normal skin. Therefore, PIRL-MS may be employed as a decision-support tool to reduce both the subjectivity of clinical diagnosis and the number of unnecessary biopsies currently required for skin cancer screening.

Concepts and recent advances in microchip electrophoresis coupled to mass spectrometry: Technologies and applications.

The online coupling of microchip electrophoresis (ME) as a fast, highly efficient, and low-cost miniaturized separation technique to mass spectrometry (MS) as an information-rich and sensitive characterization technique results in ME-MS an attractive tool for various applications. In this paper, we review the basic concepts and latest advances in technology for ME coupled to MS during the period of 2016-2021, covering microchip materials, structures, fabrication techniques, and interfacing to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization-MS. Two critical issues in coupling ME and ESI-MS include the electrical connection used to define the electrophoretic field strength along the separation channel and the generation of the electrospray for MS detection, as well as, a miniaturized ESI-tip. The recent commercialization of ME-MS in zone electrophoresis and isoelectric focusing modes has led to the widespread application of these techniques in academia and industry. Here we summarize recent applications of ME-MS for the separation and detection of antibodies, proteins, peptides, carbohydrates, metabolites, and so on. Throughout the paper these applications are discussed in the context of benefits and limitations of ME-MS in comparison to alternative techniques.

Infrared pulsed fiber laser-produced silver-109 nanoparticles for laser desorption/ionization mass spectrometry of 3-hydroxycarboxylic acids.

3-Hydroxycarboxylic acids are one of the major components of bacterial lipopolysaccharides (LPS), also known as endotoxins. Endotoxins pose a serious health risk and can seriously damage the internal organs of humans and animals. 3-Hydroxycarboxylic acids can be used as environmental markers to determine endotoxin levels. At the time of preparation of this manuscript no studies on laser mass spectrometry (MS) and analysis with silver nanoparticles (NP) for 3-hydroxycarboxylic acids have been published in literature. Six acids, 3-hydroxyoctanoic (3-OH-C8:0), 3-hydroxydecanoic (3-OH-C10:0), 3-hydroxydodecanoic (3-OH-C12:0), 3-hydroxytetradecanoic (3-OH-C14:0), 3-hydroxyhexadecanoic (3-OH-C16:0), and 3-hydroxyoctadecanoic (3-OH-C18:0) acids, were used as test compounds on the target containing silver-109 NPs for quantification using matrix-assisted laser desorption/ionization (MALDI)-type mass spectrometer. Methods were also tested on spiked human blood serum samples to quantify 3-hydroxycarboxylic acids and verify the influence of the biological matrix on the measurement. Analyzed acids were directly tested in 1000 000-fold concentration change conditions ranging from 1mg/mL to 1ng/mL. The semi-automatic MSI (MS imaging) method allowed us to obtain two to five times lower limit of detection (LOD) and lower limit of quantitation (LLOQ) values than common LDI (Bruker Daltonics, Bremen, Germany) method for analyzed acids. For almost all results of 3-hydroxycarboxylic acids, the trendline fit was better for the semi-automatic MSI method than the manual LDI method. For the first time, the use of laser MS for the quantification of 3-hydroxycarboxylic acids has been demonstrated, and it has been proven that it can be used in the quantitative analysis of such compounds over a wide range of concentrations. In addition, a comparison of two methods-manual LDI-MS and semi-automatic MSI-is presented.

Link between Polycyclic Aromatic Hydrocarbon Size and Aqueous Alteration in Carbonaceous Chondrites Revealed by Laser Mass Spectrometry

The organic inventories of carbonaceous chondrites (CCs) provide insights into the physicochemical environments involved in the Solar System’s formation and the postaccretionary evolution of meteorite parent bodies. Studying changes in these inventories across samples that have experienced varying degrees of aqueous/hydrothermal alteration untangles one aspect of such complex records. Here, the polycyclic aromatic hydrocarbon (PAH) and heterocyclic aromatic compound (HAC) contents of 15 CCs representing CI1, CM1, CM2, C2u, C3u, and CO3 classes were probed with two-step laser mass spectrometry (L2MS) and subjected to a comparative principal component analysis (PCA), a multivariate analysis method. PAHs with mass-to-charge ratios (m/z) of 128 to >300 were detected, with large PAHs (4–7 rings) dominating the spectra of the most aqueously altered samples like Ivuna (CI1) and NWA 12328 (CM1), while a larger relative fraction of smaller PAHs (3–4 rings) was observed in less altered samples like Chwichiya 002 (C3.00u). The same trend was observed across CM2 samples with varying degrees of aqueous alteration with the exception of Jbilet Winselwan (CM2.3-2.5), which has experienced impact shock. Alkylated homologues of C14H10 and C16H10 were detected in all samples, with the latter showing a stronger correlation with aqueous alteration. Additionally, oxygen-containing PAHs and thiophenes were detected. These experiments demonstrate that aqueous alteration induces aromatic condensation in CCs of multiple chemical groups, and many of the 4–7-ring PAHs (>215 m/z) in CCs may be products of aqueous alteration. Thus, PAH size distributions are an additional parameter to consider when evaluating a meteorite’s alteration history.

Multi-Faceted Mass Spectrometric Investigation of Neuropeptides in Callinectes sapidus.

Neuropeptides are signaling molecules that regulate almost all physiological and behavioral processes, such as development, reproduction, food intake, and response to external stressors. Yet, the biochemical mechanisms and full complement of neuropeptides and their functional roles remain poorly understood. Characterization of these endogenous peptides is hindered by the immense diversity within this class of signaling molecules. Additionally, neuropeptides are bioactive at concentrations 100x - 1000x lower than that of neurotransmitters and are prone to enzymatic degradation after synaptic release. Mass spectrometry (MS) is a highly sensitive analytical tool that can identify, quantify, and localize analytes without comprehensive a priori knowledge. It is well-suited for globally profiling neuropeptides and aiding in the discovery of novel peptides. Due to the low abundance and high chemical diversity of this class of peptides, several sample preparation methods, MS acquisition parameters, and data analysis strategies have been adapted from proteomics techniques to allow optimal neuropeptide characterization. Here, methods are described for isolating neuropeptides from complex biological tissues for sequence characterization, quantitation, and localization using liquid chromatography (LC)-MS and matrix-assisted laser desorption/ionization (MALDI)-MS. A protocol for preparing a neuropeptide database from the blue crab, Callinectes sapidus, an organism without comprehensive genomic information, is included. These workflows can be adapted to study other classes of endogenous peptides in different species using a variety of instruments.

Changes in the urine volatile metabolome throughout growth of transplanted hepatocarcinoma

Trained detection dogs distinguish between urine samples from healthy organisms and organisms with malignant tumors, suggesting that the volatile urine metabolome contains information about tumor progression. The aim of this study was to determine whether the stage of tumor growth affects the chemical differences in the urine of mice and to what extent the "olfactory image of disease" perceived by dogs coincides with the "image of disease" recorded by the mass spectrometer. We used a novel laser ionization mass spectrometry method and propose a mass spectrometric analysis without detailed interpretation of the spectrum of volatile metabolomes in urine. The mass spectrometer we use works without sample preparation and registers volatile organic compounds in air at room temperature without changing the pH of the sample, i.e. under conditions similar to those in which dogs solve the same problem. The experimental cancer models were male BDF-f1 hybrid mice transplanted with hepatocarcinoma tissue, and similar mice transplanted with healthy liver tissue were used as controls. Our data show that both dogs and our proposed laser mass spectrometry method are able to detect both the entire spectrum of volatile organic compounds associated with the disease and minor changes in this spectrum during its course.

The combination of laser photodissociation, action spectroscopy, and mass spectrometry to identify and separate isomers.

The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been recently deployed to meet this challenge with focus on small molecule isomers including protonation isomers, structural isomers, conformation isomers and new studies emerging on chiral isomers. Laser techniques span UV and visible laser photodissociation, time-resolved pump-probe schemes and application of laser hole-burning arrangements to assign isomers within selected ion populations. Also surveyed are applications of ion mobility strategies to separate isomers followed by laser spectroscopic techniques to assign the separated ions. Ultimately, with ongoing refinement in hardware and methods, there are clear pathways forward for laser and mass spectrometry techniques to make decisive breakthroughs in understanding how isomeric details affect biological processes, physiology and disease.

Detection techniques for monitoring dioxin-like compounds: latest techniques and the comparison

In order to clarify the necessity and urgency of dioxin detection, the characteristics and emission sources were firstly studied in this paper. The current dioxin detection techniques were then summarized, including chemical detection technique represented by HRGC/MS, biological detection technique covering immunology and biotechnology, and laser mass spectrometry technique using fusion ionization technology and time-of-flight mass spectrometry. Then the advantages and disadvantages, representative technologies, development directions and application prospects of various detection methods were analyzed. Eventually, the future development direction of dioxin detection technology was prospected.

Proximity labeling and other novel mass spectrometric approaches for spatiotemporal protein dynamics

ABSTRACT Background Proteins are highly dynamic and their biological function is controlled by not only temporal abundance changes but also via regulated protein–protein interaction networks, which respond to internal and external perturbations. A wealth of novel analytical reagents and workflows allow studying spatiotemporal protein environments with great granularity while maintaining high throughput and ease of analysis. Areas covered We review technology advances for measuring protein–protein proximity interactions with an emphasis on proximity labeling, and briefly summarize other spatiotemporal approaches including protein localization, and their dynamic changes over time, specifically in human cells and mammalian tissues. We focus especially on novel technologies and workflows emerging within the past 5 years. This includes enrichment-based techniques (proximity labeling and crosslinking), separation-based techniques (organelle fractionation and size exclusion chromatography), and finally sorting-based techniques (laser capture microdissection and mass spectrometry imaging). Expert opinion Spatiotemporal proteomics is a key step in assessing biological complexity, understanding refined regulatory mechanisms, and forming protein complexes and networks. Studying protein dynamics across space and time holds promise for gaining deep insights into how protein networks may be perturbed during disease and aging processes, and offer potential avenues for therapeutic interventions, drug discovery, and biomarker development.

CCN and INP activity of middle eastern soil dust

The term mineral dust encompasses a myriad of particle compositions from both fertile and arid regions. Due to this diversity, the quantitative understanding of mineral dust as Cloud Condensation Nuclei (CCN) and Ice Nucleating Particles (INPs) in the Earth’s atmosphere demand further investigation. This study characterizes the CCN and INP activity of mineral dust particles from samples collected from one of the Earth’s major arid regions, Saudi Arabia. Samples were size selected at particle diameters (Dp) of 300, 700, and 950 nm and introduced into a Cloud Condensation Nuclei Counter (CCNC) and a SPectrometer for Ice Nuclei (SPIN) chamber to investigate cloud nucleation activity. The chemical composition of the particles was analyzed with laser mass spectrometry and mineralogical information was provided by polarized light microscopy. Transmission electron microscopy was used to ascertain particle morphology. Each particle size was exposed to water supersaturations of 0.06–1.0% in the CCNC and to ice supersaturation ratios of 1.1 to 1.5 at temperatures from −25 to −42 °C in SPIN. The CCN activity ranged from hygroscopicity values (κ) of 0.001 to 0.01. This is towards the lower range of critical supersaturations found for other mineral dust samples from e.g. the Sahara, North Africa, China and Asia. The INP activity, defined by fractional activation and supersaturation at the onset of ice nucleation was in the range of other natural mineral dusts (e.g., the Sahara, Canary Islands), and somewhat lower than industrially processed Arizona Test Dust. This study highlights the importance of considering size-resolved compositional data when interpreting the cloud-nucleation activity of natural mineral and soil dusts.

MO057REGIONAL IMPORTANCE OF FIBRINOGEN A Α-CHAIN MUTATION ON RENAL AMYLOIDOSIS

Abstract Background and Aims Renal amyloidosis include amyloid A (AA) and light chain (AL) as well as amyloidogenic leukocyte chemotactic factor 2 (ALECT2) and numerous hereditary forms. After identifying amyloidosis by its suggestive pale pink amorphous appearance in optic microscopy (OM) and Congo red positivity, a correct diagnosis of the amyloidogenic precursor protein is determinant to establish prognosis and treatment. Immunohistochemistry (IHC) and immunofluorescence (IF) studies use a limited number of antibodies to detect specific epitopes and may be difficult to interpret. The gold standard has become proteomics but laser microdissection and mass spectroscopy are not routinely available. Other options include electron microscopy with immunogold staining and complementary exams such as scintigraphy with 99mTc-DPD to detect transthyretin-related amyloidosis. Since the cause of amyloidosis vary among regions, analyzing local patterns can help establish a diagnostic procedure. We aimed at describing cases of kidney amyloidosis identified by biopsy during a 4-year interval and discuss possible implication for future diagnosis. Method We analyzed our kidney biopsy database and selected all cases of renal amyloidosis collecting clinical, laboratory and imaging data. Results From January 2016 until December 2019, 194 kidney biopsies were performed at the Hospital of Braga in the Portuguese province of Minho. Among these, 8 (4.1%) revealed amyloidosis. Mean age was 63.8±9.2 years of age, 5 were female, 6 were referred for nephrotic syndrome and 2 for what seemed like acute kidney injury. Mean creatinine at presentation was 3.2±2.3mg/dL. Among them, 2 had AL amyloidosis with light chain restriction by IF, 1 had AA amyloidosis with intense IHC stain and 5 patients had non-AL and non-AA forms of amyloidosis. Of these, 3 had probable fibrinogen A alpha-chain (AFib) amyloidosis, after a heterozygous mutation FGA p.Glu545Val was detected, 1, who did not have IHC performed, was assumed as having AA amyloidosis due to a history of serious recurrent infections and 1 is still under study. Four performed scintigraphy with 99mTc-DPD which was negative. The 2 patients with AL amyloidosis had, by OM, in one case glomerular and tubulointerstitial and on the other, glomerular and vascular involvement and, by IF, both had k light chain restriction. Both had additional cardiac and neurovegetative involvement, were treated with cyclophosphamide-bortezomib-dexamethasone and oral doxycycline with complete hematologic response and stabilization of kidney function. In 1 case, proteinuria only showed a slow decline 2 years after treatment. The 2 patients with AA amyloidosis had glomerular, vascular and tubular deposits. One had bronchiectasis and allergic bronchopulmonary aspergillosis and the other had common variable immunodeficiency with recurrent gastrointestinal and urinary infections with frequent bacteremia. None of them had confirmed extra-renal involvement, although the latter had hepatic fibrosis awaiting biopsy. Both progressed to dialysis soon after diagnosis. The 3 patients with AFib amyloidosis all had glomerular amyloidosis with additional amyloid deposition at tubular, vascular and both respectively. Two had had an increased creatinine and subnephrotic proteinuria for some years whereas 1 had kidney function decline and nephrotic syndrome in the course of few months. All were hypertensive and none had evident extra-renal deposits. Conclusion Identifying the amyloidogenic precursor may be difficult. Algorithms for diagnosis may vary according to local prevalence of specific types and available resources. AFib amyloidosis was very significant in our series. It was also described in 4.5% of hemodialysis patients in the district of Braga making it one of the first causes of amyloidosis in our region. This high prevalence may justify early genetic testing for the specific mutation in non-AL and non-AA forms.

The importance of size ranges in aerosol instrument intercomparisons: a case study for the Atmospheric Tomography Mission

Abstract. Aerosol intercomparisons are inherently complex as they convolve instrument-dependent detection efficiencies vs. size (which often change with pressure, temperature, or humidity) and variations in the sampled aerosol population, in addition to differences in chemical detection principles (e.g., inorganic-only nitrate vs. inorganic plus organic nitrate for two instruments). The NASA Atmospheric Tomography Mission (ATom) spanned four separate aircraft deployments which sampled the remote marine troposphere from 86∘ S to 82∘ N over different seasons with a wide range of aerosol concentrations and compositions. Aerosols were quantified with a set of carefully characterized and calibrated instruments, some based on particle sizing and some on composition measurements. This study aims to provide a critical evaluation of inlet transmissions impacting aerosol intercomparisons, and of aerosol quantification during ATom, with a focus on the aerosol mass spectrometer (AMS). The volume determined from physical sizing instruments (aerosol microphysical properties, AMP, 2.7 nm to 4.8 µm optical diameter) is compared in detail with that derived from the chemical measurements of the AMS and the single particle soot photometer (SP2). Special attention was paid to characterize the upper end of the AMS size-dependent transmission with in-field calibrations, which we show to be critical for accurate comparisons across instruments with inevitably different size cuts. Observed differences between campaigns emphasize the importance of characterizing AMS transmission for each instrument and field study for meaningful interpretation of instrument comparisons. Good agreement (regression slope =0.949 and 1.083 for ATom-1 and ATom-2, respectively; SD =0.003) was found between the composition-based volume (including AMS-quantified sea salt) and that derived from AMP after applying the AMS inlet transmission. The AMS captured, on average, 95±15 % of the standard PM1 volume (referred to as the URG Corp. standard cut 1 µm cyclone operated at its nominal efficiency). These results support the absence of significant unknown biases and the appropriateness of the accuracy estimates for AMS total mass and volume for the mostly aged air masses encountered in ATom. The particle size ranges (and their altitude dependence) that are sampled by the AMS and complementary composition instruments (such as soluble acidic gases and aerosol, SAGA, and particle analysis by laser mass spectrometry, PALMS) are investigated to inform their use in future studies.