Impact of maternal topiramate ingestion on ossification of skull and appendicular bones in rat fetuses

The skull and appendicular bones are derived from different embryological sources during their development. The impact of prenatal exposure of topiramate on ossification of these bones is not adequately studied. The goal of this study was to assess the ossification patterns of the craniofacial bones and bones of the forelimbs and hindlimbs in 20-day-old rat fetuses after maternal exposure to topiramate at doses equivalent to human therapeutic doses. Three groups of Sprague-Dawley pregnant rats were used: control, topiramate 50mg/kg/day (T50) and topiramate 100mg/kg/day (T100). Topiramate was given by oral gavage from day 6 to day19 of gestation. Ossification was evaluated in the bones of 20 days fetuses after staining with Alizarin red. Results showed a significant reduction in complete ossified centers of the metacarpal, metatarsal and craniofacial bones in topiramate-exposed fetuses at both doses when compared to the control group. Also, a significant decrease in the length of ossified part of the long bones of the forelimbs and hindlimbs in topiramate-exposed fetuses at both doses was noted when compared to the control group. Crown-rump length and fetal weight were significantly decreased in topiramate treated groups compared to the control group. In all examined groups, there was a positive correlation between the crown-rump length and the lengths of humerus and femur. No abnormalities in the ossified bones and no significant changes in their ossification pattern were observed between the treated groups. In conclusion, prenatal administration of topiramate in doses equivalent to human therapeutic doses delayed ossification and development of craniofacial and appendicular bones in rat fetuses and their effects are not dose dependent at doses investigated. The implications of these findings in women who require topiramate therapy in pregnancy merit further evaluation.

The potential therapeutic efficacy of intravenous versus subconjunctival mesenchymal stem cells on experimentally ultraviolet-induced corneal injury in adult male albino rats

BACKGROUND

The X-rays and the visible light are the main source of ultraviolet radiation (UVR). About 90% of ultraviolet B (UVB) is absorbed by the cornea which may promote corneal inflammation, oedema and damage of its epithelial layer. Bone marrow mesenchymal stem cells (BM-MSCs) have been demonstrated to ameliorate the injured corneal tissue and accelerate its wound healing. This study aimed to compare the healing effect of intravenous (IV) versus subconjunctival (SC) BM-MSCs on the rats' corneas subjected to UVB-irradiation.

MATERIALS AND METHODS

Ten rats were used as donors for BM-MSCs and the other 40 were allocated into four equal groups: group I (control group), group II (ultraviolet-irradiated group), group III (ultraviolet-irradiated + IV BM-MSCs-treated group) and group IV (ultraviolet-irradiated +SC BM-MSCs-treated group). Rats of all groups were euthanized after 3 weeks and the corneal specimens were processed for histopathological, immunohistochemical and electron microscopy assessment.

RESULTS

Ultraviolet-irradiated group showed remarkable thinning of epithelial thickness, wide partial epithelial separation, and desquamation. Neovascularisation of the disorganised stroma and disrupted Descemet's membrane were observed. The superficial and basal epithelial cells appeared irregular and separated by wide intercellular spaces and inflammatory cells. Immunohistochemical examination showed a significant decrease in proliferating cell nuclear antigen immunoreaction. In contrast, minimal changes were observed in rats treated with BM-MSCs with more improvement associated with the subconjunctival administration compared to IV route.

CONCLUSIONS

Local SC injection of BM-MSCs has an amazing regenerative efficacy on the corneal injury compared to the systemic IV route.

Learning anatomy before and during COVID-19 pandemic: Students' perceptions and exam performance

The objective of our study was to explore the impact of COVID-19 pandemic on learning anatomy and to compare the students’ perceptions of “face-to-face” and “online” anatomy teaching, and to assess their impact on student's performance. We used a descriptive, cross-sectional, questionnaire-based study that focused on a single cohort of undergraduate medial students who attended anatomy demonstrations, at the College of Medicine and Medical Sciences, Arabian Gulf University (CMMS-AGU), both pre-pandemic (face-to-face) during 2019-2020 and the pandemic (online) during 2020-2021. Students who participated in this study responded in favor of face-to-face demonstrations for better understanding of the spatial orientation of body organs and systems, the visualization of the anatomical relations between structures, understanding the difficult anatomical structures, understanding the clinical correlations, and making them more confident about their practical exams. On the other hand, students were in favor of online demonstrations for retaining key information, confidence levels on discussing anatomy learning needs, effective utilization of demonstration time, and lower stress associated with the online learning. Regarding anatomy exam scores, statistically significant difference was found between mean scores of online and onsite exams in one of the two analyzed multiple choice questions tests. However, there was a statistically significant difference between the mean scores of objective structured practical examination of online and onsite exams in the two analyzed tests. Furthermore, the majority of the students who participated in the survey prefer a mixture of both face-to-face and online anatomy demonstrations during the pandemic and also in the post-COVID-19 era.