Influence of rheologically weak layers on fault architecture: insights from analogue models in the context of the Northern Alpine Foreland Basin

We present a series of analogue models inspired by the geology of the Zürcher Weinland region in the NorthernvAlpine Foreland Basin of Switzerland to explore the influence of rheological weak, i.e. (partially) ductile layers on the 3D evolution of tectonic deformation. Our model series test the impact of varying weak layer thickness and rheology, as well as different kinematics of an underlying “basal fault”. Model analysis focuses on deformation in the weak layer overburden and, uniquely, within the weak layer itself. We find that for low to moderate basal fault displacements, the above-mentioned parameters strongly influence the degree of coupling between the basal fault and the weak layer overburden. Coupling between the basal fault and overburden decreases by reducing the strength of the weak layer, or by increasing the weak layer’s thickness. As a result, basal fault displacement is less readily transferred through the weak layer, leading to a different structural style in the overburden. By contrast, increasing the amount, or rate, of basal fault slip enhances coupling and leads to a more similar structural style between basal fault and overburden. Moreover, dip-slip displacement on the basal fault is more readily transferred to the overburden than strike-slip displacement of the same magnitude. Our model results compare fairly well to natural examples in the Northern Alpine Foreland Basin, explaining various structural features. These comparisons suggest that rheological weak layers such as the Jurassic Opalinus Clay have exerted a stronger control on fault zone architecture than is commonly inferred, potentially resulting in vertical fault segmentation and variations in structural style. Furthermore, the novel addition of internal marker intervals to the weak layer in our models reveals how complex viscous flow within these layers can accommodate basal fault slip. Our model results demonstrate the complex links between fault kinematics, mechanics and 3D geometries, and can be used for interpreting structures in the Alpine Foreland, as well as in other settings with similar weak layers and basal faults driving deformation in the system

A Case of Anti-SAE1 Dermatomyositis

INTRODUCTION: Anti-SAE1 antibodies have a low prevalence in dermatomyositis patients. Case Description. A 61-year-old woman presented with progressive shortness of breath, arthralgia, heliotrope rash, Gottron's papules, and erythematous rash. She had an interstitial lung disease (ILD) with a significant decrease in lung function. There was no muscle involvement. Immunological laboratory test results showed strongly positive anti-SAE1 antibodies. Glucocorticoid treatment resulted in remission of dermatomyositis. CONCLUSION: Anti-SAE antibodies in dermatomyositis patients are closely linked to unique clinical features

From VGKC to LGI1 and Caspr2 encephalitis: The evolution of a disease entity over time

A wide variety of clinical syndromes has been associated with antibodies to voltage-gated potassium channels (VGKCs). Six years ago, it was discovered that patients do not truly have antibodies to potassium channels, but to associated proteins. This enabled the distinction of three VGKC-positive subgroups: anti-LGI1 patients, anti-Caspr2 patients and VGKC-positive patients lacking both antibodies. Patients with LGI1-antibodies have a limbic encephalitis, often with hyponatremia, and about half of the patients have typical faciobrachial dystonic seizures. Caspr2-antibodies cause a more variable syndrome of peripheral or central nervous system symptoms, almost exclusively affecting older males. Immunotherapy seems to be beneficial in patients with antibodies to LGI1 or Caspr2, stressing the need for early diagnosis. Half of the VGKC-positive patients lack antibodies to both LGI1 and Caspr2. This is a heterogeneous group of patients with a wide variety of clinical syndromes, raising the question whether VGKC-positivity is truly a marker of disease in these patients. Data regarding this issue are limited, but a recent study did not show any clinical relevance of VGKC-positivity in the absence of antibodies to LGI1 and Caspr2. The three VGKC-positive subgroups are essentially different, therefore, the lumping term ‘VGKC-complex antibodies’ should be abolished

Mono-sensitisation to peanut component Ara h 6: a case series of five children and literature review

Here, we summarise the current clinical knowledge on Ara h 6 sensitisation and clinical relevance of this sensitisation pattern using five illustrative clinical cases. The literature search yielded a total of 166 papers, and an additional relevant article was found by ‘snowballing’. A total of ten articles were considered relevant for this review. Most studies included patients with a sensitisation to Ara h 6 and cosensitisation to Ara h 2. Only three studies showed patients with a mono-sensitisation to Ara h 6. This illustrates that Ara h 6 mono-sensitisation has been neglected in literature. We present a case series of five children with sensitisation to peanut component Ara h 6. Only one of these five patients showed Ara h 8 cosensitivity. Three out of the five children had a positive double-blind placebo-controlled food challenge (DBPCFC), with moderate to strong reactions. Conclusion: A mono-sensitisation to peanut component Ara h 6 is uncommon but can cause severe allergic reactions. Therefore, the determination of sIgE to Ara h 6 is warranted in patients with a suspected peanut allergy, especially in the absence of sensitisation to Ara h 1, 2, 3 and 9.(Table presented.

The Basophil Activation Test Is Not a Useful Screening Tool for Hymenoptera Venom-Related Anaphylaxis in Patients with Systemic Mastocytosis

Background: Systemic mastocytosis (SM) patients are at a high risk for anaphylaxis, with Hymenoptera as the main culprit. A screening instrument to identify which patients are sensitized to Hymenoptera before they experience anaphylaxis would therefore be of great value. The basophil activation test (BAT) is proposed as a possible tool for diagnosing Hymenoptera venom-related allergy (HVA), especially in patients in whom conventional allergy tests yield contradictory results. Methods: We included outpatients with SM, according to WHO criteria, from September 2011 to January 2012. Next, to obtain various clinical data including intradermal test results, specific immunoglobulin E (sIgE) measurements and BAT were performed. Results: We included 29 patients, 9 of whom had a history of HVA and 4 of whom had experienced anaphylaxis due to other triggers. Sixteen patients had no history of anaphylaxis. sIgE was detected in 6 patients with HVA and in 2 patients with anaphylaxis due to other triggers. The BAT was positive in only 1 patient, in whom the skin test and sIgE were also positive. Compared to patients with skin lesions, those without skin lesions had significantly more anaphylaxis and sIgE to Hymenoptera. During a 3-year follow-up, no one experienced new anaphylactic episodes. Conclusion: The BAT is not a reliable tool for randomly screening SM patients for HVA