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.

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.

Effect of prenatal administration of therapeutic doses of topiramate on ossification of ribs and vertebrae in rat fetuses

There are few studies that have addressed the effects of prenatal exposure of topiramate on ossification of the bones derived from the paraxial mesoderm. This study aimed to evaluate skeletal ossification of ribs and vertebrae in 20-day-old rat fetuses after maternal exposure to two therapeutic doses of topiramate. Three groups of Sprague-Dawley pregnant rats were used: control, topiramate 50 mg/kg/day and topiramate 100 mg/kg/day treated groups. Topiramate was administered by gavage from day 6-19 of gestation. Fetuses were collected on day 20 by caesarean section. Fetal bones were stained with alizarin red and ossification was assessed. Results showed significant delayed ossification of ribs and vertebrae in topiramate-exposed fetuses at both doses and the effects were not dose dependent. In all examined groups, there was a direct correlation between the fetal weight and the number of complete ossified vertebral centers. Also, there were significant increases in skeletal abnormalities, particularly in ribs in both treated groups when compared to the control group. In conclusion, therapeutic doses of topiramate should be taken cautiously during pregnancy as they lead to fetal growth restriction and increases abnormalities of axial skeleton in rat fetuses.

Nephrotoxicity of low-dose methotrexate in guinea pigs: an ultrastructural study

The nephrotoxicity of low-dose methotrexate (MTX) and the rescue effect of leucovorin were studied by electron-microscopic examination of the kidney of guinea pigs. One group received MTX as a single weekly dose of 10 mg/kg, i.p.; a second group received a similar dose divided into three equal fractions. The third group received MTX rescued with an equal dose of leucovorin. The distal convoluted tubule showed cell swelling, fragmentation of the endoplasmic reticulum and loss of mitochondrial cristae and matrix. Leucovorin minimized these changes. The proximal tubule and the glomerulus were not affected. Low-dose MTX induced a nephrotoxicity in the distal convoluted tubule which could be minimized by leucovorin. Mild myelosuppression was also observed.

The superficial ulnar artery: development and surgical significance

The upper limbs of 72 formalin-fixed human cadavers were examined by dissection for arterial anomalies. In one subject, the ulnar artery was noted to be a branch of the second part of the axillary artery on both right and left sides. It ran a superficial course in the arm, crossed the elbow immediately subjacent to the median cubital vein, and continued its course in the forearm in a subcutaneous position. In the hand it played a dominant role in the formation of the superficial palmar arch. The anomalous ulnar artery was of a smaller caliber than both the radial and common interosseous arteries. Although superficial ulnar arteries have been reported in the literature, the combination of bilateral superficial ulnar arteries originating from the axillary arteries appears to be rare. The developmental and surgical significance of the findings are discussed.

Extensor tendons of the fingers: arrangement and variations--II

One hundred eighty-one dissected hands were examined to study the pattern of extensor tendons on the dorsum of the hand. Extensor digitorum often had multiple tendons for the middle and ring fingers. Its contribution to the little finger was usually by a bifurcating tendon common with that of the ring finger. The index finger always received a single tendon. Intertendinous connections between the various tendons of the extensor digitorum were variable but were most frequent between ring and middle fingers. Extensor indicis had one tendon in most of the specimens and it was always on the ulnar side of the extensor digitorum tendon. This remained true even when there were multiple tendons. Extensor digiti minimi had two tendons in most cases. It was always linked to extensor digitorum either by receiving one or part of its tendon or by an intertendinous connection. Two accessory muscles were seen, one was extensor indicis brevis replacing the proper muscle. The other, the extensor medii brevis, was distributed to the middle finger.

Ossification of the vertebral column in the offspring of rats exposed to alcohol, acetaldehyde and caffeine

The embryopathic effects of alcohol have been widely studied in humans and laboratory animals. However, the role of risk factors remains largely unknown. Whereas skeletal abnormalities are often present in the offspring of alcoholic mothers, these have not been fully documented. This report is concerned specifically with the development of the vertebral column in rats exposed in utero to ethanol, its primary metabolite acetaldehyde, and caffeine. Our results indicate a possible causal association between alcohol abuse and ossification anomalies of the vertebral column. Maternal treatment with caffeine accelerated ossification in the sacro-caudal vertebrae. Caffeine combined with ethanol only moderately affected the development of the centra and arches.

Effects of alcohol and caffeine on cultured whole rat embryos

The direct effects of ethanol and caffeine on embryogenesis were investigated using the whole rat embryo culture system. Compared to control embryos, the crown-rump length, number of somites, branchial bars, and morphological score were significantly reduced in embryos exposed to ethanol, caffeine, or both substances. Development of the craniofacial region, cardiac primordium and forelimb was delayed following ethanol treatment. Compared to the controls, the anterior neuropore lagged in development following caffeine treatment; closure of the posterior neuropore was significantly delayed in each of the treatment groups. The optic and olfactory primordia were not affected. The results indicate that alcohol and caffeine independently affect the embryo, but when combined their effects were not potentiated.