Spaceborne Observations of Lightning NO2 in the Arctic

The Arctic region is experiencing notable warming as well as more lightning. Lightning is the dominant source of upper tropospheric nitrogen oxides (NO_x), which are precursors for ozone and hydroxyl radicals. In this study, we combine the nitrogen dioxide (NO₂) observations from the TROPOspheric Monitoring Instrument (TROPOMI) with Vaisala Global Lightning Dataset 360 to evaluate lightning NO₂ (LNO₂) production in the Arctic. By analyzing consecutive TROPOMI NO₂ observations, we determine the lifetime and production efficiency of LNO₂ during the summers of 2019-2021. Our results show that the LNO₂ production efficiency over the ocean is ∼6 times higher than over continental regions. Additionally, we find that a higher LNO₂ production efficiency is often correlated with lower lightning rates. The summertime lightning NO_x emission in the Arctic (north of 70° N) is estimated to be 219 ± 116 Mg of N, which is equal to 5% of anthropogenic NO_x emissions. However, for the span of a few hours, the Arctic LNO₂ density can even be comparable to anthropogenic NO₂ emissions in the region. These new findings suggest that LNO₂ can play an important role in the upper-troposphere/lower-stratosphere atmospheric chemical processes in the Arctic, particularly during the summer.

Trajectories of sickness absence and disability pension by type of occupation in multiple sclerosis

Background

Multiple sclerosis (MS) can impact working life, sickness absence (SA), and disability pension (DP). Different types of occupations involve different demands, which may be associated with trajectories of SA and DP among people with MS (PwMS). We aim to explore if annual levels of SA and DP differ according to type of occupation among PwMS and references. Further, we aim to gain knowledge of how trajectories of SA and DP are associated with type of occupation among PwMS.

Methods

A nationwide Swedish register-based prospective cohort study with six-year follow-up was conducted, including 6,100 individuals with prevalent MS and 38,641 matched population references. Mean annual SA and DP net days during follow-up years were calculated and stratified by type of occupation. Trajectories of SA and DP were identified with group-based trajectory modelling. Multinomial logistic regressions were estimated for associations between identified trajectories and different types of occupations.

Results

An increase of SA and DP over time in all types of occupations was observed in both PwMS and references, with higher levels of SA and DP among PwMS. Managers had the lowest levels of SA and DP in both groups. Three SA and DP trajectory groups were identified: Persistently Low (55.2%), Moderate Increasing (31.9%), and High Increasing (12.8%). Managers (Odds Ratio [OR] 0.37, 95%CI 0.26-0.52) and those working in Science & Technology (OR 0.64, 95% CI 0.50-0.82) had less probability of belonging to the Moderate Increasing group. Similarly, Managers (OR 0.52, 95%CI 0.30-0.89) and Science & Technology (OR 0.58, 95%CI 0.39-0.88) had also less probability of belonging to the High Increasing group.

Conclusions

Our findings suggest that the type of occupation plays a role in the level and course of SA and DP among PwMS.

Key messages

Over time SA and DP levels increased among PwMS regardless of type of occupation. PwMS in Managers or Science and Technology had less probability of belonging to the increasing trajectories.

Cytomegalovirus antigenemia as a useful marker of symptomatic cytomegalovirus infection after renal transplantation--a report of 130 consecutive patients

In earlier work we demonstrated that CMV immediate early antigens can be detected in peripheral blood leukocytes of patients with active CMV infection. We now report a comparison of the antigenemia assay and an anti-CMV ELISA in a prospective longitudinal study of 130 renal transplant recipients who were monitored for active CMV infection during the first 3 months after transplantation. Active CMV infection developed in 56 patients. The antigenemia assay had a sensitivity of 89% and a specificity of 93% in the diagnosis of active CMV infection; for the ELISA these figures were 95 and 100%, respectively. In 22 of the 56 patients a CMV syndrome occurred. Antigenemia was demonstrated in all 22 patients while an antibody response occurred in 21 of them. The antigenemia assay became positive 8 +/- 7 days before the onset of symptoms while the antibody response was observed 4 +/- 9 days after the onset of symptoms. The pattern of antigenemia was helpful for monitoring the course of the infection. The maximum level of antigenemia was significantly higher and its duration significantly longer in symptomatic than asymptomatic infection. We conclude that CMV antigenemia is a sensitive, specific, and early marker of CMV infection. The antigenemia assay is of great value in monitoring patients with a high risk of CMV infection.

[Current developments in the diagnosis and therapy of cytomegalovirus infections]

We describe the case history of a 40-year-old, negroid woman with systemic lupus erythematosus who acquired a severe cytomegalovirus infection on immunosuppression; this infection was successfully treated with ganciclovir. New ideas in the management of CMV infections in immuno-compromised hosts are discussed. The traditional diagnostics are unsatisfactory, antibody detection being very insensitive and culture techniques too slow. A new diagnostic approach by detection of the immediate early antigens of the cytomegalovirus (CMV-IEA) using monoclonal antibodies is fast and reliable (sensitivity 93%, specificity 92%), even in case of immuno-deficiency. Finally we discuss the efficacy of the antiviral agent ganciclovir in the management of severe CMV infections.

Complement activation during an active cytomegalovirus infection after renal transplantation: due to circulating immune complexes or alternative pathway activation?

In 32 patients with a renal allograft, serial determinations after transplantation were made of C3d, the stable conversion product of the complement factor C3, as well as serial measurements of the anaphylatoxin C3a des arg. Furthermore, serial determinations were made on the presence of circulating immune complexes using three different assays (C1q binding assay, polyethylene glycol precipitation test, and indirect granulocyte phagocytosis test). Twenty patients were studied during an active cytomegalovirus (CMV) infection, and 12 patients were studied during allograft rejection or during stable phase after renal transplantation. In 12 patients with a CMV infection serial measurements were made of AP50 (alternative pathway of complement). During an active CMV infection elevated C3d as well as elevated C3a des arg levels were found and not in the control group (P less than 0.01). In 8 out of the 12 patients tested, with CMV infection, a decreased hemolytic activity of the alternative pathway (AP50) was found, together with the elevated levels of C3d and C3a des arg. Serum C4 levels were normal or high during CMV infection. Furthermore, circulating immune complexes were found to be positive in 15 out of the 20 patients with a CMV infection (both primary and secondary infections), and in 2 out of 12 patients of the control group. The complement activation found in the CMV group was not related to the presence of circulating immune complex-like material, since complement activation was present in advance of the appearance of the immune complexes, suggesting that complement activation was not due to classical pathway activation by those complexes. We conclude that our data are consistent with complement activation and the formation of biologically active peptides like C3a des arg in patients with an active CMV infection. The decreased hemolytic activity of the alternative pathway (AP50) together with the normal or high C4 levels suggest involvement of the alternative pathway, although further studies of the alternative pathway of C are warranted to confirm this hypothesis.

Rapid immunodiagnosis of active cytomegalovirus infection by monoclonal antibody staining of blood leucocytes

The appearance of cytomegalovirus (CMV) antigen positive blood leucocytes (CMV antigenaemia) was investigated in 52 renal transplant recipients during the first three months after transplantation. Using a mixture of three monoclonal antibodies, CMV (immediate early) antigens were detected in cytocentrifuged blood leucocytes within 3-5 h after sampling. The results were related to virus isolation from buffy coats (CMV viraemia), serology with a sensitive enzyme-linked immunosorbent assay (ELISA), and clinical symptoms of CMV disease. The antigen test was positive in all 14 patients with CMV viraemia, in 25 out of 27 of patients with serological evidence of primary or secondary CMV infection, and in 2 out of 25 patients without active infection. In patients with a clinical CMV syndrome the presence of CMV antigen (CMV-Ag) positive blood cells correspond with the period of signs and symptoms. CMV antigens were not detected in 23 out of 25 patients without active infection, nor in healthy controls and patients with other herpesvirus infections. CMV-Ag positive blood cells appeared, on average, nine days before serological signs of active infection. This method provides a rapid and sensitive approach to CMV detection, enabling early clinical diagnosis and subsequent tapering of immunosuppression or commencement of antiviral therapy.