A wide temporal window for conjunctival papillae development ensures the formation of a complete sclerotic ring

Abstract

Papilla regeneration is a mechanism that ensures the formation of a complete sclerotic ring and provides another level of redundancy for the induction of a complete sclerotic ring during the normal inductive period. Developmental Dynamics 246:381-391, 2017. © 2017 Wiley Periodicals, Inc.

Intrauterine Growth Restriction Affects Cerebellar Granule Cells in the Developing Guinea Pig Brain

“…We were not able to test whether the deficits suggestive of impaired migration identified here lead to long-term motor and/or cognitive deficits. However, our previous studies have shown that IUGR guinea pigs demonstrate altered sensorimotor gating in adolescence assessed using prepulse inhibition of the acoustic startle response [56]. Although not a cognitive test per se, such abnormalities in sensorimotor gating are considered predictive of, or may lead to, cognitive deficits [57].…”

An overlooked placode: Recharacterizing the papillae in the embryonic eye of reptilia

“…As each placode is induced, it undergoes morphological development to form a distinct papilla, which renders it inductively active. 79 This regenerative potential is present from HH30 to HH35; by HH35 induction of the underlying scleral condensations, it is fully underway. This skeletogenic induction event occurs beginning at HH34 through to HH36.…”

“…[2][3][4] In the chicken, this papilla is visible at Hamburger and Hamilton (HH) stage 30. 4,74,79 Once the conjunctival papillae have completed their inductive role, they degenerate. 4,74 Although this spatiotemporal patterning is still poorly understood, Fyfe and Hall 78 provided evidence for an initial mesenchymal signal that induces each placode, similar to other cutaneous placodal systems.…”

“…4,74 Although this spatiotemporal patterning is still poorly understood, Fyfe and Hall 78 provided evidence for an initial mesenchymal signal that induces each placode, similar to other cutaneous placodal systems. 79 This regeneration is possible because the contiguous regions surrounding the papillae remain competent to respond to the inductive cue, which is still expressed in the underlying mesenchyme. The papillae then induce the underlying mesenchymal scleral condensations, which ultimately differentiate into a series of scleral ossicles.…”

“…The papillae then induce the underlying mesenchymal scleral condensations, which ultimately differentiate into a series of scleral ossicles. 79 4,74,79 Once the conjunctival papillae have completed their inductive role, they degenerate.…”