Vaughan H. Lee

The cardiac sodium channel mRNA is expressed in the developing and adult rat and human brain.

Expression of the rat (RH-I/SkM2) and human (hH1/SCN5A) tetrodotoxin-resistant (TTX-R), voltage-sensitive sodium channels is thought to be specific to cardiac tissue. We detected RH-I/SkM2 mRNA in newborn rat brain using both RNase protection assay analysis and in situ hybridization and in adult rat brain using RNase protection assay analysis. This expression was observed primarily in developing limbic structures of the cerebrum and diencephalon, and in the medulla of the brain stem. Using RT-PCR analysis, we detected hH1/SCN5A mRNA in both fetal and adult human brain. Interestingly, mutations in the human cardiac sodium channel are known to lead to cardiac abnormalities, which result in arrhythmias and frequently in sudden cardiac death. If these mutant channels were also expressed in limbic regions of the brain, alterations in channel function could have drastic effects on the brains signaling ability, possibly promoting seizure activity.

A retrospective look at replacing face‐to‐face embryology instruction with online lectures in a human anatomy course

Embryology is integrated into the Clinically Oriented Anatomy course at the Texas Tech University Health Sciences Center School of Medicine. Before 2008, the same instructor presented embryology in 13 face‐to‐face lectures distributed by organ systems throughout the course. For the 2008 and 2009 offerings of the course, a hybrid embryology instruction model with four face‐to‐face classes that supplemented online recorded lectures was used. One instructor delivered the lectures face‐to‐face in 2007 and by online videos in 2008–2009, while a second instructor provided the supplemental face‐to‐face classes in 2008–2009. The same embryology learning objectives and selected examination questions were used for each of the three years. This allowed direct comparison of learning outcomes, as measured by examination performance, for students receiving only face‐to‐face embryology instruction versus the hybrid approach. Comparison of the face‐to‐face lectures to the hybrid approach showed no difference in overall class performance on embryology questions that were used all three years. Moreover, there was no differential effect of the delivery method on the examination scores for bottom quartile students. Students completed an end‐of‐course survey to assess their opinions. They rated the two forms of delivery similarly on a six‐point Likert scale and reported that face‐to‐face lectures have the advantage of allowing them to interact with the instructor, whereas online lectures could be paused, replayed, and viewed at any time. These experiences suggest the need for well‐designed prospective studies to determine whether online lectures can be used to enhance the efficacy of embryology instruction. Anat Sci Educ 7: 234–241.

Expression of Rabbit Zona Pellucida-1 Messenger Ribonucleic Acid During Early Follicular Development

Abstract Progress in research on initiation of folliculogenesis has progressed slowly because of a lack of markers for early folliculogenesis. The rabbit zona pellucida protein (ZP1) is synthesized in follicles during early stages of folliculogenesis. In order to establish ZP1 as a marker for initiation of folliculogenesis, in situ hybridization was used to localize ZP1 mRNA in immature follicles. ZP1 mRNA was first detected in oocytes of some but not all primordial follicles. The primordial follicles expressing ZP1 mRNA were located at the cortico-medullary junction, indicating that they were newly activated follicles. ZP1 mRNA accumulated in oocytes of intermediate, primary, and secondary follicles. In contrast, ZP1 mRNA was first detectable in granulosa cells of intermediate follicles and is present in cuboidal granulosa cells of primary and early secondary follicles, but was undetectable in granulosa cells of more mature follicles. These data demonstrate that 1) ZP1 mRNA is expressed in both oocytes and granulosa cells, 2) ZP1 mRNA is initially expressed in oocytes of activated follicles, and 3) ZP1 mRNA is transiently expressed in granulosa cells during early stages of folliculogenesis. Therefore, rabbit ZP1 is a molecular marker that can be used in future studies to measure initiation of folliculogenesis.

Expression of RUSH Transcription Factors in Developing and Adult Rabbit Gonads

Abstract The RUSH transcription factors 1α and 1β bind to the Rabbit Uteroglobin promoter and are members of the SWI/SNF complex that facilitates transcription by remodeling chromatin (Helicase). To characterize gonadal expression of RUSH, a cRNA probe that recognizes both isoforms was used for in situ hybridization studies. We found RUSH mRNA to be abundant in Sertoli cells from embryonic, neonatal, prepubertal, and pubertal rabbit testes. In adults, RUSH mRNA was detected in tubules with preleptotene spermatocytes and mature spermatids lining the lumen. However, RUSH was undetectable in tubules that contained leptotene spermatocytes and that lacked mature spermatids. In females, RUSH was expressed in presumptive granulosa cells of embryonic and neonatal ovaries before follicle organization. Abundant RUSH mRNA was detected in granulosa and theca cells surrounding preantral follicles of prepubertal and adult ovaries. Expression of RUSH remained high in granulosa cells of antral follicles in mature ovaries but was negligible in late-stage atretic follicles and in corpora lutea. Western blot analysis confirmed the RUSH-1α isoform predominated in both testicular and ovarian tissues. The expression pattern of RUSH indicates transcriptional activity in Sertoli cells and during multiple stages of differentiating granulosa cells, especially those of primordial follicles, which heretofore were considered to be dormant.