John P. Robertson

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OBJECTIVE Because of the intricate anatomy of the temporal bone, we examined the feasibility and reliability of cranial surface anatomic fiducials to register computed tomographic images of the temporal bone by using a frameless image-guided system. METHODS One-millimeter thick computed tomographic slices and the smallest possible field of view were used(More)
Advances in nanotechnology have led to the development of novel fluorescent probes called quantum dots. Quantum dots have revolutionalized the processes of tagging molecules within research settings and are improving sentinel lymph node mapping and identification in vivo studies. As the unique physical and chemical properties of these fluorescent probes are(More)
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Cholesterol granulomas of the head are relatively rare. Isolated lesions of the cerebellopontine angle are even more uncommon. In this report, 17 cases of petrous apex cholesterol granulomas are presented and management is discussed. Symptoms at presentation included dizziness (14 patients), pressure (nine patients), tinnitus (eight patients), hearing loss(More)
Two cases of left atrial myxoma are reviewed, both presenting as embolic phenomena. Neither patient gave a history compatible with pre-existent cardiac dysfunction. Sudden collapse and subsequent right hemiplegia resulted in one patient when an embolus lodged in the left middle cerebral artery. The second patient presented with headache and transient visual(More)
Gene expression is widely used for the characterisation of breast cancers. Variability due to tissue heterogeneity or measurement error or systematic change due to peri-surgical procedures can affect measurements but is poorly documented. We studied the variability of global gene expression between core-cuts of primary ER+ breast cancers and the impact of(More)
Twelve recent cases of Mycobacterium tuberculosis meningitis were presented, and the literature was reviewed. There are no particularly new or unique therapies or approaches to the management of this most serious disease. The major obstacle to successful diagnosis and treatment of tuberculous meningitis continues to be a lack of clinical suspicion of its(More)
We derive midpoint criteria for solving Pell's equation x 2 − Dy 2 = ±1, using the nearest square continued fraction expansion of √ D. The period of the expansion is on average 70% that of the regular continued fraction. We derive similar criteria for the diophantine equation x 2 − xy − (D−1) 4 y 2 = ±1, where D ≡ 1 (mod 4). We also present some numerical(More)
Five cases of sarcoid presenting as an intracranial tumor are reported. In one instance, the lesion presented as a tumor in the cerebellopontine angle, a site not previously reported for the initial presentation of sarcoid isolated to the central nervous system. The role of computerized tomography, surgery, and steroid therapy is discussed. In the absence(More)