The role of environmental feedback in a brain state switch from passive to active sensing

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Non-invasive Loading Model of Murine Osteoarthritis

Osteoarthritis is the commonest degenerative joint disease, leading to joint pain and disability. The mouse has been the primary animal used for research, due to its size, relatively short lifespan, and the availability of genetically modified animals. Importantly, they show pathogenesis similar to osteoarthritis in humans. Mechanical loading is a major risk factor for osteoarthritis, and various mouse models have been developed to study the role and effects of mechanics on health and disease in various joints. This review describes the main mouse models used to non-invasively apply mechanical loads on joints. Most of the mouse models of osteoarthritis target the knee, including repetitive loading and joint injury such as ligament rupture, but a few studies have also characterised models for elbow, temporomandibular joint, and whole-body vibration spinal loading. These models are a great opportunity to dissect the influences of various types of mechanical input on joint health and disease

Corollary discharge inhibition and audition in the stridulating cricket

The romantic notion of crickets singing on a warm summer's evening is quickly dispelled when one comes ear to ear with a stridulating male. Remarkably, stridulating male crickets are able to hear sounds from the environment despite generating a 100db song (Heiligenberg 1969; Jones and Dambach 1973). This review summarises recent work examining how they achieve this feat of sensory processing. While the responsiveness of the crickets' peripheral auditory system (tympanic membrane, tympanic nerve, state of the acoustic spiracle) is maintained during sound production, central auditory neurons are inhibited by a feedforward corollary discharge signal precisely timed to coincide with the auditory neurons' maximum response to self-generated sound. In this way, the corollary discharge inhibition prevents desensitisation of the crickets' auditory pathway during sound productio

Implementation of the JAK2V617F mutation analysis in the pathway of suspected myeloproliferative neoplasms in Groote Schuur Hospital

We studied the implementation of JAK2 mutation analysis in conjunction with the World Health Organisation (WHO) guidelines in the pathway to MPN diagnosis in 279 patients presenting with one of three clinical scenarios: erythrocytosis, OR leukocytosis and/or thrombocytosis and/or splenomegaly; OR patients with thrombosis without cytoses. Patients were investigated for MPN and managed in the haematology clinic of Groote Schuur Hospital. We studied the association of clinical and laboratory variables with clonal vs non-clonal diagnoses. In 120/297 patients MPN was confirmed: Polycythemia vera (PV), (n=51, 100% JAK2 mutated); essential thrombocytosis, (n=41, 42% JAK2 mutated); primary myelofibrosis (n=28, 57% JAK2 mutated). The 2016 WHO haemoglobin/haematocrit thresholds in PV were validated. Idiopathic erythrocytosis (IE) found in 44 patients. Bone marrow histology, but not serum EPO level, was essential to differentiate between clonal and non-clonal erythrocytosis. Both PV and IE patients complied with the criteria of absolute erythrocytosis on peripheral blood, yet nuclear red cell mass identified critical differences between clonal and non-clonal erythrocytosis. No patient venesected for nonclonal erythropoiesis developed thrombocytosis. JAK2 mutation analysis applied with the WHO diagnostic algorithm efficiently differentiated true clonal myeloproliferation from reactive cytoses. Lifestyle and metabolic factors such as smoking and thrombosis were not associated with either clonal or non-clonal erythrocytosis, and were equally present in mutated and unmutated essential thrombocytosis

A density theorem for the difference Galois groups of regular singular Mahler equations

The difference Galois theory of Mahler equations is an active research area. The present paper aims at developing the analytic aspects of this theory. We first attach a pair of connection matrices to any regular singular Mahler equation. We then show that these connection matrices can be used to produce a Zariski-dense subgroup of the difference Galois group of any regular singular Mahler equation