Harmonization of criteria and terminology in fetal rat skeletal evaluations.

Background: A survey of laboratories in North American and Europe that routinely conduct fetal skeletal examinations was performed with the purpose of (1) understanding current terminology used for classifying skeletal findings in developmental toxicity (DT) studies and (2) understanding the criteria used to identify relatively common findings that sufficiently deviate from normal. The goal was to promote terminology harmonization and improve interlaboratory consistency in the criteria used to identify developmental anomalies.

Methods: The survey, designed based on terminology for developmental anomalies recommended by an international collaboration (Makris et al.

Concordance between alizarin red stained skeleton and micro-CT skeleton evaluation methods: A case study in New Zealand White rabbits.

Objectives: The objective of this study was to examine the fetal skeletons using both alizarin red stain and micro-computed tomography (CT) images; investigate differences, and to determine if the conclusions of the study were the same regardless of the examination method.

Methods: A candidate drug was given orally by gavage to pregnant New Zealand White rabbits on gestation day (GD) 7 to GD 19 (mating = GD 0) at doses of 0 (control), 0.02, 0.

No developmental toxicity observed with dolutegravir in rat whole embryo culture.

Background: An in vitro rat whole embryo culture study investigated whether direct exposure to dolutegravir (Tivicay ) during the critical period for neural tube development would result in abnormal development.

Methods: Dolutegravir (DTG), and HIV integrase inhibitor, was administered at 0 (vehicle), 5.3 μg/mL and 9.

The use of micro-CT imaging to examine and illustrate fetal skeletal abnormalities in Dutch Belted rabbits and to prove concordance with Alizarin Red stained skeletal examination.

Objectives: In our laboratory we evaluated the use of micro-computed tomography (micro-CT) using a high resolution acquisition protocol and fetuses obtained on Gestation Day (GD) 29 (mating = GD 0).

Methods: To show concordance between traditional Alizarin Red S stain and micro-CT skeletal examination methods, 103 fetuses from 19 untreated Dutch belted rabbits were obtained by cesarean section and stored frozen. The fetuses were thawed, imaged and examined digitally by micro-CT, then stained and re-examined using traditional methods.

Comparison of a modified mid-coronal sectioning technique and Wilson's technique when conducting eye and brain examinations in rabbit teratology studies.

Background: There are two methods used when examining fetal rabbit eyes and brain in teratology studies. One method employs prior fixation before serial sectioning (Wilson's technique) and the other uses fresh tissue (mid-coronal sectioning).

Methods: We modified the mid-coronal sectioning technique to include removal of eyes and brain for closer examination and to increase the number of structures that can be evaluated and compared it to the Wilson's technique.