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From ballerinas in movies and on TikTok, to models in pointe shoes, distortion can be harmful

To understand the process of fin-fold formation in detail, we systematically dissected how different cell types within the zebrafish fin arise. Muscle and vascular precursors have previously been demonstrated to [...], The transition from fins to limbs was an important terrestrial adaptation, but how this crucial evolutionary shift arose developmentally is unknown. Current models focus on the distinct roles of the apical ectodermal ridge (AER) and the signalling molecules that it secretes during limb and fin outgrowth. In contrast to the limb AER, the AER of the fin rapidly transitions into the apical fold and in the process shuts off AER-derived signals that stimulate proliferation of the precursors of the appendicular skeleton (1-10). The differing fates of the AER during fish and tetrapod development have led to the speculation that fin-fold formation was one of the evolutionary hurdles to the AER-dependent expansion of the fin mesenchyme required to generate the increased appendicular structure evident within limbs (11). Consequently, a heterochronic shift in the AER-to-apical-fold transition has been postulated to be crucial for limb evolution (11). The ability to test this model has been hampered by a lack of understanding of the mechanisms controlling apical fold induction (11,12). Here we show that invasion by cells of a newly identified somite-derived lineage into the AER in zebrafish regulates apical fold induction. Ablation of these cells inhibits apical fold formation, prolongs AER activity and increases the amount of fin bud mesenchyme, suggesting that these cells could provide the timing mechanism proposed in Thorogood's clock model of the fin-to-limb transition (11). We further demonstrate that apical-fold-inducing cells are progressively lost during gnathostome evolution; the absence of such cells within the tetrapod limb suggests that their loss may have been a necessary prelude to the attainment of limb-like structures in Devonian sarcopterygian fish.

Aim: To survey Australasian neonatal medical and nursing staff to determine confidence regarding medication use, prior experience with medication errors and common resources utilised in neonatal emergencies. Methods: Data were collected through a cross‐sectional online survey distributed to clinical staff affiliated with the Australian and New Zealand Neonatal Network. Information collected included: demographics, confidence in medication use, medication errors and resources used to assist with medication administration. Outcomes were compared between medical staff and nursing staff, and between clinical staff with differing levels of clinical experience (<5 years, 5–10 years and >10 years). Results: Respondents (n = 133) were most confident in calculating medication doses (89%, n = 119), but least confident in prescribing medication (50%, n = 67). Nurses were more likely to be confident than doctors with respect to appropriately diluting and drawing up medication (88% nurses vs. 28% doctors, P < 0.0001), and administering intravenous medications to critically ill neonates (97% nurses vs. 82% doctors, P < 0.01). Over half of respondents reported being personally involved in a medication error in the last 12 months: 33% had been involved in an error related to delayed administration, 18% related to incorrect documentation and 17% related to an incorrect dose. Free‐text responses highlighted issues relating to adrenaline (epinephrine) administration and difficulties with equipment (syringe drivers and/or infusion pumps). Conclusions: Medication errors in neonatal emergencies are common. Strategies to reduce such errors should be implemented in settings where neonates may require emergency care or resuscitation. [ABSTRACT FROM AUTHOR]