Biomedical subjects

Stephen J Moorman

Publications and source records attributed to Stephen J Moorman.

5 recordsLinked to original sources

PubMed2006

Prof-in-a-Box: using internet-videoconferencing to assist students in the gross anatomy laboratory.

BACKGROUND: The optimal learning environment for gross anatomy is the dissection laboratory. The Prof-in-a-Box (PiB) system has been developed where an anatomist using distance-learning technologies 'helps' students in a dissection laboratory at a different site. METHODS: The PiB system consists of: (1) an anatomist in his/her office with a computer and video camera; (2) a computer and 2 video cameras in the lab; (3) iChat AV software; (4) a secure server to host the PiB-student 'consultation'. The PiB system allows the students and faculty to interact via audio and video providing an environment where questions can be asked and answered and anatomical structures can be identified 'at a distance' in real-time. The PiB system was set up at a prosected cadaver and made available for student use during 'office hours'. RESULTS: 25-30% of the students used the PiB system. Anatomical structures were identified, questions answered and demonstrations given 'at a distance' using the system. Students completed an optional questionnaire about the PiB system at the end of the semester. Results of the questionnaire indicate that the students were enthusiastic about the PiB system and wanted its use to be expanded in the future. CONCLUSION: Many of the functions of a faculty member in the gross anatomy dissection laboratory can be performed 'at a distance' using the PiB system. This suggests that a geographically dispersed faculty could assist in providing instruction in the dissection labs at multiple medical schools without needing to be physically present.

Adult↗

PubMed2006

Changes in gravitational force cause changes in gene expression in the lens of developing zebrafish.

Gravity has been a constant physical factor during the evolution and development of life on Earth. We have been studying effects of simulated microgravity on gene expression in transgenic zebrafish embryos expressing gfp under the influence of gene-specific promoters. In this study, we assessed the effect of microgravity on the expression of the heat shock protein 70 (hsp70) gene in lens during development using transgenic zebrafish embryos expressing gfp under the control of hsp70 promoter/enhancer. Hsp70:gfp expression was up-regulated (45%) compared with controls during the developmental period that included the lens differentiation stage. This increase was lens specific, because the entire embryo showed only a 4% increase in gfp expression. Northern blot and in situ hybridization analysis indicated that the hsp70:gfp expression recapitulated endogenous hsp70 mRNA expression. Hypergravity exposure also increased hsp70 expression during the same period. In situ hybridization analysis for two lens-specific crystallin genes revealed that neither micro- nor hypergravity affected the expression level of betaB1-crystallin, a non-hsp gene used as a marker for lens differentiation. However, hypergravity changed the expression level of alphaA-crystallin, a member of the small hsp gene family. Terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) assay analysis showed that altered-gravity (Deltag) decreased apoptosis in lens during the same period and the decrease correlated with the up-regulation of hsp70 expression, suggesting that elimination of nuclei from differentiating lens fiber cells was suppressed probably through hsp70 up-regulation. These results support the idea that Deltag influences hsp70 expression and differentiation in lens-specific and developmental period specific manners and that hsp family genes play a specific role in the response to Deltag.

Animals↗

PubMed2006

Zebrafish pax5 regulates development of the utricular macula and vestibular function.

The zebrafish otic vesicle initially forms with only two sensory epithelia, the utricular and saccular maculae, which primarily mediate vestibular and auditory function, respectively. Here, we test the role of pax5, which is preferentially expressed in the utricular macula. Morpholino knockdown of pax5 disrupts vestibular function but not hearing. Neurons of the statoacoustic ganglion (SAG) develop normally. Utricular hair cells appear to form normally but a variable number subsequently undergo apoptosis and are extruded from the otic vesicle. Dendrites of the SAG persist in the utricle but become disorganized after hair cell loss. Hair cells in the saccule develop and survive normally. Otic expression of pax5 requires pax2a and fgf3, mutations in which cause vestibular defects, albeit by distinct mechanisms. Thus, pax5 works in conjunction with fgf3 and pax2a to establish and/or maintain the utricular macula and is essential for vestibular function.

Acoustic Maculae↗

PubMed2005

Changes in gravitational force affect gene expression in developing organ systems at different developmental times.

BACKGROUND: Little is known about the affect of microgravity on gene expression, particularly in vivo during embryonic development. Using transgenic zebrafish that express the gfp gene under the influence of a beta-actin promoter, we examined the affect of simulated-microgravity on GFP expression in the heart, notochord, eye, somites, and rohon beard neurons. We exposed transgenic zebrafish to simulated-microgravity for different durations at a variety of developmental times in an attempt to determine periods of susceptibility for the different developing organ systems. RESULTS: The developing heart had a period of maximum susceptibility between 32 and 56 hours after fertilization when there was an approximately 30% increase in gene expression. The notochord, eye, somites, and rohon beard neurons all showed periods of susceptibility occurring between 24 and 72 hours after fertilization. In addition, the notochord showed a second period of susceptibility between 8 and 32 hours after fertilization. Interestingly, all organs appeared to be recovering by 80 hours after fertilization despite continued exposure to simulated-microgravity. CONCLUSION: These results support the idea that exposure to microgravity can cause changes in gene expression in a variety of developing organ systems in live embryos and that there are periods of maximum susceptibility to the effects.

Animals↗

PubMed2002

A critical period for functional vestibular development in zebrafish.

We have determined a critical period for vestibular development in zebrafish by using a bioreactor designed by NASA to simulate microgravity for cells in culture. A critical period is defined as the briefest period of time during development when stimulus deprivation results in long lasting or permanent sensory deficits. Zebrafish eggs were collected within 3 hours of being laid and fertilized. In experiment 1, eggs were placed in the bioreactor at 3, 24, 30, 36, 48, or 72 hours postfertilization (hPF) and maintained in the bioreactor until 96 hPF. In experiment 2, eggs were placed in the bioreactor immediately after they were collected and maintained in the bioreactor until 24, 36, 48, 60, 66, 72, or 96 hPF. Beginning at 96 hPF, all larvae had their vestibulo-ocular reflexes (VOR) evaluated once each day for 5 days. Only larvae that hatched from eggs that were placed in the bioreactor before 30 hPF in experiment 1 or removed from the bioreactor later than 66 hPF in experiment 2 had VOR deficits that persisted for at least 5 days. These data suggest a critical period for vestibular development in the zebrafish that begins before 30 hPF and ends after 66 hPF. To confirm this, zebrafish eggs were placed in the bioreactor at 24 hPF and removed at 72 hPF. VORs were evaluated in these larvae once each day for 5 days beginning at 96 hPF. These larvae had VOR deficits that persisted for at least 5 days. In addition, larvae that had been maintained in the bioreactor from 24 to 66 hPF or from 30 to 72 hPF, had only temporary VOR deficits. In a final experiment, zebrafish eggs were placed in the bioreactor at 3 hPF and removed at 96 hPF but the bioreactor was turned off from 24 hPF to 72 hPF. These larvae had normal VORs when they were removed from the bioreactor at 96 hPF. Taken as a whole, these data support the idea that there is a critical period for functional maturation of the zebrafish vestibular system. The developmental period identified includes the timeframe during which the vestibular primary afferent neurons are born, innervate their central and peripheral targets, and remodel their central projections.

Animals↗