Assessing photoreceptor structure after macular hole closure.

PURPOSE: To describe photoreceptor structure and recovery after macular hole (MH) closure with pars plana vitrectomy (PPV) using adaptive optics scanning light ophthalmoscopy and spectral domain optical coherence tomography. METHODS: A pilot imaging study of four eyes from four subjects undergoing PPV for MH was conducted. Imaging with spectral domain optical coherence tomography and adaptive optics scanning light ophthalmoscopy was performed at varying time points after PPV. RESULTS: Despite successful MH closure, disruption of the foveal inner segment ellipsoid zone was seen in all patients when imaged at a mean of 117 days after PPV. Disruption of the photoreceptor mosaic was seen using adaptive optics scanning light ophthalmoscopy at locations corresponding to regions of ellipsoid zone disruption on spectral domain optical coherence tomography. Cone density immediately surrounding these disruptions was normal, except for one patient. In 2 patients who were imaged serially up to 516 days after PPV, recovery of cone cells within regions of mosaic disruption could be detected over time. CONCLUSION: Photoreceptor disruption exists even after apparent MH closure. Remodeling of the foveal cone mosaic continues for many months after surgery, perhaps accounting for the delayed postoperative improvements of visual acuity in some patients. Spectral domain optical coherence tomography and adaptive optics scanning light ophthalmoscopy are useful tools for monitoring photoreceptor recovery after surgical closure of MH.

RFLP analysis and allelic discrimination with real-time PCR using the human lactase persistence trait: A pair of molecular genetic investigations.

We describe here two open-ended laboratory investigations for an undergraduate laboratory course that uses students' DNA as templates for quantitative real-time PCR and for traditional PCR followed by RFLP analysis. Students are captivated by the immediacy of the application and the relevance of the genotypes and traits, lactase persistence or nonpersistence, under study. Concepts ranging from nucleotide polymorphisms to natural selection can be demonstrated and reinforced by these laboratories. Students have a high degree of success with the laboratories and both objective and self-assessments of student learning indicate that concepts and techniques are better understood following implementation of these laboratory investigations.

Designing laboratory exercises for the undergraduate molecular biology/biochemistry student: Techniques and ethical implications involved in personalized medicine.

Personalized medicine refers to medical care that involves genetically screening patients for their likelihood to develop various disorders. Commercial genome screening only involves identifying a consumer's genotype for a few single nucleotide polymorphisms. A phenotype (such as an illness) is greatly influenced by three factors: genes, gene expression levels, and the environment. The information supplied by personal genomics companies only involves genes and as such is not always indicative of a particular phenotype. Here, we propose a method for developing modular undergraduate laboratories that examine each contributing factor for a single gene. Although each module is suitable as an individual laboratory exercise, every module may be used in the same class to examine a single phenotype of interest, give students a more complete understanding of how a phenotype is produced and allow students to understand the science behind personalized medicine.