Figure 1.

The effect of hydrocortisone (HC) injections at Hamburger and Hamilton (HH) 29 and HH 30 on scleral condensations. (A–D) Examples of the categories of morphological defects used to classify the scleral condensations of HH 37 embryos injected with a high dose of HC. All embryos are stained for alkaline phosphatase (AP); images are oriented with the beak to the right. (A) Normal embryos have no defects in scleral condensation morphology. (B) Mild defects of blurring (indistinct) condensation borders. (C) Moderate defects with abnormal condensation sizes and a few gaps in the ring. (D) Severe defects with large gaps in the condensation ring. Scale bars: 1 mm. (E) Summary of HC injection time points, doses and numbers of embryos used to determine the optimum dosage for maximum effect. Control no injection (CNI) and control injections (CI) were conducted for each HC treatment (n = 6–14 embryos per control group). These embryos were raised to HH 37 to evaluate the effect on scleral condensation development. (F,G) Graphs showing the percentage of embryos injected with different HC treatments, and the effects on the morphology of scleral condensations (F) and on the number of scleral condensations (G).