Gilberto Gonzalez

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Few studies have described the metabolic substrates underlying neuropsychological performance in HIV infection or examined the specificity of these relationships. The authors performed magnetic resonance spectroscopic and neuropsychological evaluations on 61 patients with AIDS dementia complex (stages 1-3) and 39 HIV-positive neurologically asymptomatic(More)
PURPOSE To study the spontaneous low-frequency blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signal fluctuations during hyperacute focal cerebral ischemia. MATERIALS AND METHODS A stroke model in nonhuman primates (macaques) was used in this study. Spontaneous fluctuations were recorded using a series of gradient-recalled echo (GRE)(More)
Primary pituitary lymphoma in immunocompetent patients is a rare disease and has been described in less than 20 cases. Moreover, low-grade lymphomas constitute only 3% of all primary central nervous system lymphoma. The objective of this report is to report a low-grade primary pituitary lymphoma, diagnostic problems and to give more evidence about the(More)
A 38-year-old right-handed woman, who had suffered a left cerebral hemisphere infarction, was studied. She developed right hemiparesis, motor and sensory aphasia, and left hand mirror writing. All possible brain mechanisms involved in writing, either perceptual or motor, were investigated in search of the one responsible for her mirror writing; however, no(More)
OBJECTIVE To determine the frequency of occult macroscopic metastasis detected by preoperative US evaluation of the neck in patients with PTC. Papillary thyroid carcinoma (PTC) is a malignancy with a high rate of lymph node metastasis. The findings of routine thyroid ultrasonography (US) and physical examination may underestimate metastatic disease. Thus,(More)
Vitamin D status has been extensively studied throughout the world. However, most of the studies are from North America, Europe and Oceania. This review describes published evidence on vitamin D status among healthy postmenopausal women in South America, where food is not fortified with vitamin D. A literature search identified ten studies from only three(More)
A cute ischemic stroke is common and often treatable. Imaging by computed tomography (CT) and MRI is valuable for stroke treatment, in addition, for diagnosis, and for identification of the pathogenesis. But how they are used also depends on practical considerations. The approach to imaging the patient with acute stroke used at the Massachusetts General(More)
mathematical models where the dimensions of the matrices are very large, the use of classical methods to compute the singular values is very time consuming and requires a lot of computational resources. In this way, it is necessary to find new faster methods to compute the singular values of a very large matrix. We present a method to estimate the singular(More)
Acknowledgments I feel very grateful for having had the opportunity to pursue my doctoral degree at HST and for the support, the help and the encouragement from the people I met during my graduate studies. I thank my advisor, Dr. Robert Mulkern, who educated me in many aspects of research. His willingness to spend time discussing problems, to help in(More)
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