A5012363487- Advanced MRI Techniques and Applications
- Pain Mechanisms and Treatments
- Botulinum Toxin and Related Neurological Disorders
- HIV Research and Treatment
- Functional Brain Connectivity Studies
- Advanced NMR Techniques and Applications
- Advanced Neuroimaging Techniques and Applications
- Pharmacological Effects and Toxicity Studies
- Pain Management and Placebo Effect
- Neurological disorders and treatments
- Electron Spin Resonance Studies
- Herpesvirus Infections and Treatments
- Leprosy Research and Treatment
- Musculoskeletal pain and rehabilitation
- EEG and Brain-Computer Interfaces
- Pediatric Pain Management Techniques
- Posttraumatic Stress Disorder Research
- NMR spectroscopy and applications
- HIV-related health complications and treatments
- Psychosomatic Disorders and Their Treatments
- Neurological and metabolic disorders
- Bone and Joint Diseases
- Atomic and Subatomic Physics Research
- Neuroinflammation and Neurodegeneration Mechanisms
- Muscle and Compartmental Disorders
University of California San Diego Medical Center
2022
University of California, San Diego
2011-2022
VA San Diego Healthcare System
2011-2021
Neurobehavioral Research (United States)
2015-2019
Wellcome Centre for Integrative Neuroimaging
2009
University of Oxford
2009
University of California, San Francisco
1995-2006
Massachusetts General Hospital
1998-2000
Harvard University
1997-2000
Massachusetts Institute of Technology
1997
Abstract Dynamic measurements of regional changes in cerebral blood volume (CBV) were performed rat models hypercarbia and focal neuronal activation using T 2 ‐weighted imaging after injection an intravascular contrast agent with a very long half‐life. Calculated percent CBV change during was consistent literature results from other non‐invasive modalities. Equivalent increases found spin‐ gradient‐echo images, suggesting proportional for capillaries small veins. During electrical...
Abstract Objective The groin pain experienced by patients with hip osteoarthritis (OA) is often accompanied areas of referred and changes in skin sensitivity. We aimed to identify the supraspinal influences that underlie these clinical manifestations we consider indicative possible central sensitization. Methods Twenty OA awaiting joint replacement displaying signs were recruited into study, together age‐matched controls. All subjects completed psychology questionnaires underwent...
We use a novel balanced experimental design to specifically investigate brain mechanisms underlying the modulating effect of expected pain intensity on afferent nociceptive processing and perception. used two visual cues, each conditioned one noxious thermal stimuli [∼48°C (high) or 47°C (low)]. The cues were presented just before during application stimulus. Subjects reported significantly higher when stimulus was preceded by high-intensity cue. To control for expectancy effects, one-half...
Abstract The metabolic activation resulting from direct dopaminergic stimulation can be detected using auto‐radiography, positron emission tomography (PET) or, potentially, fMRI techniques. To establish the validity of latter possibility, we have performed a number experiments. We measured regional selectivity two different ligands: dopamine release compound D‐amphetamine and transporter antagonist 2β‐carbomethoxy‐3β‐(4‐fluoropheny) tropane (CFT). Both compounds led to increased signal...
Abstract A high frequency solution of the electromagnetic field produced by a circular surface coil adjacend to homogenous conducting, dielectric sphere is used predict attainable signal noise ratio ( S/N ) and specific absorption rate (SAR) for in vivo 1 H NMR spec troscopy experiments from 200 430 MHz (4.7–10T). Above increases more rapidly with SAR less compared respective dependence below MHz. The difference due resonances magnetic inside at frequencies above It predicted that may be...
Abstract The changes in hydrostatic pressure and electrical potentials across vessels the human vasculature presence of a large static magnetic field are estimated to determine feasibility vivo NMR spectroscopy at fields as high 10 T. A 10‐T vascular model by less than 0.2%. An exact solution magnetohydrodynamic equations describing conducting fluid flowing transverse nonconducting, straight, circular tube is used. This compared an approximate that assumes no induced has led previous...
Abstract A proton MR spectral editing technique employing a spatially localized, double‐quantum filter (DQF) was used to measure γ‐aminobutyric acid (GABA) in the human brain at 1.5 T. The method provided robust, single‐shot suppression of uncoupled resonances from choline, creatine, and NAA allowed detection γCH 2 GABA (3.0 ppm) resonance with 30% efficiency. Spatial localization measurement achieved by incorporating PRESS within excitation sequence. calibration developed adjust relative...
Despite modern combination antiretroviral therapy, distal neuropathic pain (DNP) continues to affect many individuals with HIV infection. We evaluated risk factors for new-onset DNP in the CNS Antiretroviral Therapy Effects Research (CHARTER) study, an observational cohort. Standardized, semiannual clinical evaluations were administered at 6 US sites. Distal was defined by using a clinician-administered instrument standardized across All participants analyzed free of study entry. New-onset...
Abstract A proton magnetic resonance spectral editing technique is presented that uses PRESS excitation to achieve spatially localized measurements of brain gamma‐aminobutyric acid (GABA). The homonuclear difference spectroscopy employs a frequency selective inversion pulse suppress the creatine at 3.0 ppm. timing this optimized maximize suppression by minimizing effect on ppm resonances. achieves three dimensional spatial localization in single acquisition making it less sensitive patient...
. Despite modern antiretroviral therapy, HIV-associated neuropathy is one of the most prevalent, disabling and treatment-resistant complications HIV disease. The presence intensity distal neuropathic pain not fully explained by degree peripheral nerve damage. A better understanding brain structure in may help explain why some patients with report while majority does not. Previously, we reported that more intense was associated smaller total cerebral cortical gray matter volumes. objective...
Medical comorbidities accumulate in older persons living with HIV (PLWH), causing disability and reduced quality of life. Sensory neuropathy polypharmacy may contribute to balance difficulties falls. The contribution is understudied.To evaluate the chronic distal sensory polyneuropathy (cDSPN) disturbances among PLWH.Ambulatory PLWH HIV- adults (N = 3379) were prospectively studied. All participants underwent a neurologic examination document objective abnormality diagnostic cDSPN reported...
Abstract A double‐quantum filter (DQF) sequence with PRESS localization was developed for in vivo detection of the glucose resonances 3.85‐ppm region brain proton spectrum. The efficiency and spectral editing characteristics were studied phantom animal experiments. Approximately 45% achieved at 4.7 T TE = 68 ms. Since DQF method is dependent on relative phases RF pulses, a phase calibration procedure used to correct shifts induced by spatial localization. In addition detecting approximately...
Laparoscopic radiofrequency ablation is used to treat unresectable metastatic liver tumors. It minimally invasive and associated with few side effects. Reported complications from this procedure include bleeding (1,2), hyperbilirubinemia (1), pleural effusion (2), cholecystitis intrahepatic abscess (3), minor skin burn (4). We describe a case of complicated by hemolysis, rhabdomyolysis, transient acute renal failure. Case Report A 57-yr-old male carcinoid tumor unknown primary origin was...
Many of those aging with HIV suffer from distal neuropathic pain (DNP) due to HIV-associated sensory neuropathy (HIV-SN). Prior studies have linked chronic conditions a variant the catechol-O-methyltransferase (COMT), ValMet. This confers reduced enzymatic activity and results in higher synaptic dopamine levels. Here we examined role ValMet as predictor DNP HIV-SN.In 1044 HIV-infected individuals enrolled CNS Antiretroviral Therapy Effects Research, an observational study across six US...
Distal sensory polyneuropathy (DSP) is a disabling consequence of human immunodeficiency virus (HIV), leading to poor quality life and more frequent falls in older age. Neuropathic pain paresthesia are prevalent symptoms; however, there currently no known curative treatments the longitudinal course HIV-associated DSP poorly characterized.
Abstract Mechanisms underlying chronic neuropathic pain associated with HIV-associated distal sensory polyneuropathy are poorly understood, yet 40% of those neuropathy (or 20% all people HIV) suffer from this debilitating condition. Central processing mechanisms thought to contribute the development HIV pain, studies investigating central for few. Considering motivational nature we aimed examine degree which expectation onset and offset altered in sixty-one male patients HIV-related (N = 30)...