1,603 research outputs found
Adeno-Associated Virus 8-Mediated Gene Therapy for Choroideremia: Preclinical Studies in in Vitro ind in Vivo Models
Choroideremia (CHM) is a slowly progressive X-linked retinal degeneration that results ultimately in total blindness due to loss of photoreceptors, retinal pigment epithelium, and choroid. CHM, the gene implicated in choroideremia, encodes Rab escort protein-1 (REP-1), which is involved in the post-translational activation via prenylation of Rab proteins. We evaluated AAV8.CBA.hCHM, a human CHM encoding recombinant adeno-associated virus serotype 8 (rAAV8) vector, which targets retinal cells efficiently, for therapeutic effect and safety in vitro and in vivo in a murine model of CHM. In vitro studies assayed the ability of the vector to produce functional REP-1 protein in established cell lines and in CHM patient derived primary fibroblasts. Assays included Western blots, immunofluorescent labeling, and a REP-1 functional assay which measured the ability of exogenous REP-1 to prenylate Rab proteins. The in vivo work used unilateral subretinal delivery of AAV8.hCHM to treat a murine model of CHM, with the effects of treatment evaluated with pupillometry, ophthalmoscopy, histology, and immunofluorescence analysis. The contralateral eye was treated with an AAV8.EGFP control. The results of the in vitro analysis demonstrated that the AAV8.CBA.hCHM vector was capable of inducing robust expression of REP-1 protein in a dose-responsive fashion in cultured cells, with the prenylation assay indicating that the exogenous REP-1 protein produced was capable of assisting in the activation of Rab proteins. This functional assay was also applied to CHM patient fibroblasts transduced with an AAV serotype 2 version of the vector and demonstrated that exogenous REP-1 produced in these cells was functional. The in vivo subretinal treatment of CHM mice with AAV8.CBA.hCHM resulted in the improvement of pupillary response in the treated eyes of some animals, as well as slowing of progression as judged by ophthalmoscopy. Histology of treated animals showed properly localized expression of human REP-1 and a significant improvement in outer retina health as determined by an increase in the thickness of the outer nuclear layer in treated eyes compared to controls. Combined, these results indicate that transduction with AAV8.CBA.hCHM reduces the biochemical and pathogenic defects in CHM both in vitro and in vivo and supports the application of AAV8 vectors in CHM gene therapy
Written corrective feedback: preferences and justifications of teachers and students in a Thai context
This study investigates the preferences and justifications of teachers and students on written
corrective feedback (WCF) at a tertiary institution in Thailand and is aimed at expanding on
prior similar studies conducted with smaller data sets in different contexts. Quantitative and
qualitative questionnaire data were collected from 262 intermediate students and 21 teachers
in order to test two hypotheses: (1) teachers’ and students’ WCF preferences would differ
significantly, and (2) their justifications for their preferences would differ significantly. The
hypotheses were confirmed: teachers rated indirect feedback with metalinguistic comment as
being most useful while students most preferred direct feedback with metalinguistic
comment. This trend extended to all types of direct feedback being preferred by students
while teachers preferred all types of indirect feedback. The most common explanation for the
teachers’ preferences was the development of metacognitive skills, while accuracy was the
greatest concern for students. The pedagogical implications of the results regarding
expectations, student agency, and self-efficacy are discussed
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