Lyme neuroborreliosis: Progressive cerebral vasculitis responsive to cyclophosphamide. A case report and review of the literature.

OBJECTIVES: Less than 1 % of patients with Lyme Neuroborreliosis (LNB) present with a cerebrovascular event. Ischaemic strokes occur more commonly than parenchymal or subarachnoid haemorrhages. If cerebral vasculitis due to LNB is suspected, antibiotic treatment should be started immediately, which will normally lead to remission. Very rarely progression and recurrent strokes are observed despite sufficient antibiotic therapy, even if steroids are added. Currently there are no guidelines on the adequate treatment of cerebral vasculitis due to LNB which is not responsive to antibiotics and steroids, but in very few reported cases cyclophosphamide led to disease stabilisation. We reviewed the literature regarding cyclophosphamide treatment in these patients and want to share our experience of cyclophosphamide therapy in progressive cerebral vasculitis due to LNB. RESULTS: We report a 71-year-old female patient with cerebral vasculitis and multiple strokes as a complication of LNB. Progression could only be halted by additional immunosuppressive treatment using cyclophosphamide. However, at that point the patient had already suffered severe ischaemic brain damage. Similarly, in existing case reports cyclophosphamide had been administered only at a time when patients already showed serious neurological deficits. CONCLUSION: Cerebral vasculitis in patients with LNB is very rare and normally responds to antibiotic treatment. A minority of patients show disease progression despite antibiotics and steroids. Our case report strengthens the recommendation that in those patients - even if signs of progressive vasculitis are only detectable on imaging and not clinically - cyclophosphamide should be considered without delay to prevent further cerebrovascular events.

Inorganic Salt Interference on CO2+ in Aerodyne AMS and ACSM Organic Aerosol Composition Studies.

Aerodyne aerosol mass spectrometer (AMS) and Aerodyne aerosol chemical speciation monitor (ACSM) mass spectra are widely used to quantify organic aerosol (OA) elemental composition, oxidation state, and major environmental sources. The OA CO2+ fragment is among the most important measurements for such analyses. Here, we show that a non-OA CO2+ signal can arise from reactions on the particle vaporizer, ion chamber, or both, induced by thermal decomposition products of inorganic salts. In our tests (eight instruments, n = 29), ammonium nitrate (NH4NO3) causes a median CO2+ interference signal of +3.4% relative to nitrate. This interference is highly variable between instruments and with measurement history (percentiles P10-90 = +0.4 to +10.2%). Other semi-refractory nitrate salts showed 2-10 times enhanced interference compared to that of NH4NO3, while the ammonium sulfate ((NH4)2SO4) induced interference was 3-10 times lower. Propagation of the CO2+ interference to other ions during standard AMS and ACSM data analysis affects the calculated OA mass, mass spectra, molecular oxygen-to-carbon ratio (O/C), and f44. The resulting bias may be trivial for most ambient data sets but can be significant for aerosol with higher inorganic fractions (>50%), e.g., for low ambient temperatures, or laboratory experiments. The large variation between instruments makes it imperative to regularly quantify this effect on individual AMS and ACSM systems.

Corrigendum: Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition.

This corrects the article DOI: 10.1038/sdata.2017.3.

Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition.

Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data. The observatories represent nine different environments, e.g., Arctic, Atlantic, Pacific and Mediterranean maritime, boreal forest, or high alpine atmospheric conditions. This is a unique collection of aerosol particle properties most relevant for studying aerosol-cloud interactions which constitute the largest uncertainty in anthropogenic radiative forcing of the climate. The dataset is appropriate for comprehensive aerosol characterization (e.g., closure studies of CCN), model-measurement intercomparison and satellite retrieval method evaluation, among others. Data have been acquired and processed following international recommendations for quality assurance and have undergone multiple stages of quality assessment.