Publications by authors named "Gregory Wong"

Despite the development of various cancer treatment methods, chemotherapy remains the most common approach for treating cancer. The risk of tumors acquiring resistance to chemotherapy remains a significant hurdle to the successful treatment of various types of cancer. Therefore, overcoming or predicting multidrug resistance in clinical treatment is essential.

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The Mars Science Laboratory rover, , explored the clay mineral-bearing Glen Torridon region for 1 Martian year between January 2019 and January 2021, including a short campaign onto the Greenheugh pediment. The Glen Torridon campaign sought to characterize the geology of the area, seek evidence of habitable environments, and document the onset of a potentially global climatic transition during the Hesperian era. roved 5 km in total throughout Glen Torridon, from the Vera Rubin ridge to the northern margin of the Greenheugh pediment.

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Obtaining carbon isotopic information for organic carbon from Martian sediments has long been a goal of planetary science, as it has the potential to elucidate the origin of such carbon and aspects of Martian carbon cycling. Carbon isotopic values (δC) of the methane released during pyrolysis of 24 powder samples at Gale crater, Mars, show a high degree of variation (-137 ± 8‰ to +22 ± 10‰) when measured by the tunable laser spectrometer portion of the Sample Analysis at Mars instrument suite during evolved gas analysis. Included in these data are 10 measured δC values less than -70‰ found for six different sampling locations, all potentially associated with a possible paleosurface.

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Coronavirus disease 2019 (COVID-19) has widened patient care gaps and created gaps in medical student clinical training. The care gaps are often most obvious in primary care medicine clinics (PCMCs) where residents and medical students care for a vulnerable population. We designed an outpatient telehealth program to support and monitor PCMC patients who had been diagnosed or were suspected to have COVID-19 and were confined to their homes due to public health mandated isolation.

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Background And Purpose: Clot fragmentation and distal embolization during endovascular thrombectomy for acute ischemic stroke may produce emboli downstream of the target occlusion or in previously uninvolved territories. Susceptibility-weighted magnetic resonance imaging can identify both emboli to distal territories (EDT) and new territories (ENT) as new susceptibility vessel signs (SVS). Diffusion-weighted imaging (DWI) can identify infarcts in new territories (INT).

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Background: Because "time is brain," acute stroke trials are migrating to the prehospital setting. The impact upon enrollment in post-arrival trials of earlier recruitment in a prehospital trial requires delineation.

Methods: We analyzed all patients recruited into acute and prevention stroke trials during an 8-year period when an academic medical center (AMC) was participating in a prehospital treatment trial - the NIH Field Administration of Stroke Treatment - Magnesium (FAST-MAG) study.

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Importance: Studies of neurological deterioration in stroke have focused on the subacute period, but stroke treatment is increasingly migrating to the prehospital setting, where the neurological course has not been well delineated.

Objective: To describe the frequency, predictors, and outcomes of neurological deterioration among patients in the ultra-early period following ischemic stroke or intracranial hemorrhage.

Design, Settings, And Participants: Exploratory analysis of the prehospital, randomized Field Administration of Stroke Therapy-Magnesium (FAST-MAG) Trial conducted from 2005 to 2013 within 315 ambulances and 60 stroke patient receiving hospitals in Southern California.

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Every spacecraft sent to Mars is allowed to land viable microbial bioburden, including hardy endospore-forming bacteria resistant to environmental extremes. Earth's stratosphere is severely cold, dry, irradiated, and oligotrophic; it can be used as a stand-in location for predicting how stowaway microbes might respond to the martian surface. We launched E-MIST, a high-altitude NASA balloon payload on 10 October 2015 carrying known quantities of viable Bacillus pumilus SAFR-032 (4.

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A challenge for the design of scaffolds in tissue engineering is to determine a terminal sterilization method that will retain the structural and biochemical properties of the materials. Since commonly used heat and ionizing energy-based sterilization methods have been shown to alter the material properties of protein-based scaffolds, the effects of ethanol and ethylene oxide (EtO) sterilization on the cellular compatibility and the structural, chemical, and mechanical properties of uncrosslinked, UV crosslinked, or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) crosslinked fibrin microthreads in neutral (EDCn) or acidic (EDCa) buffers are evaluated. EtO sterilization significantly reduces the tensile strength of uncrosslinked microthreads.

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Objectives: To determine whether gastrointestinal (GI) symptoms (abdominal pain, nonpain GI symptoms, nausea) and/or psychosocial distress differ between children with/without gastroparesis and whether the severity of GI symptoms and/or psychosocial distress is related to the degree of gastroparesis.

Study Design: Children aged 7-18 years (N = 100; 63 female patients) undergoing a 4-hour gastric emptying scintigraphy study completed questionnaires evaluating GI symptoms, anxiety, and somatization for this prospective study. Spearman correlation, Mann-Whitney, t-test, and χ(2) tests were used as appropriate for statistical analysis.

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Background: Esophagogastroduodenoscopy (EGD) and gastric emptying scintigraphy (GES) are commonly performed in the evaluation of children with upper gastrointestinal symptoms. It has been presumed, but not clarified, that gastroparesis increases the likelihood of identifying abnormalities on EGD. We sought to determine whether the presence of gastroparesis influenced the diagnostic yield of EGD in children.

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This paper reports a micromachined drug delivery device that is wirelessly operated using radiofrequency magnetic fields for implant applications. The controlled release from the drug reservoir of the device is achieved with the microvalves of poly(N-isopropylacrylamide) thermoresponsive hydrogel that are actuated with a wireless resonant heater, which is activated only when the field frequency is tuned to the resonant frequency of the heater circuit. The device is constructed by bonding a 1-mm-thick polyimide component with the reservoir cavity to the heater circuit that uses a planar coil with the size of 5-10 mm fabricated on polyimide film, making all the outer surfaces to be polyimide.

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Background: Brain-derived neurotrophic factor (BDNF) plays an important role in the regulation of synaptic plasticity and neurotransmitter release across multiple neurotransmitter systems. Recent studies have suggested that BDNF plays a role in the pathogenesis of bipolar disorder (BPD). Moreover, increasing BDNF production might be one of the mechanisms involved in the alleviation of depression and aggravation of mania in antidepressant treatment.

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A number of linkage studies have previously implicated the region of chromosome 13q34 in schizophrenia. Chumakov and colleagues (2002) identified a gene complex called G72 (now termed D-amino acid oxidase activator: DAOA)/G30 in this region and performed association analyses of the DAOA/G30 as well as the D-amino-acid oxidase (DAAO) gene with schizophrenia. DAAO oxidizes D-serine, a potent activator of the N-methyl-D-aspartate (NMDA) type glutamate receptor in the human brain whereas the DAOA protein is considered an activator of DAAO.

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The NR2B protein is a critical structural and functional subunit of the NMDA glutamate receptor. The glutamate neurotransmitter system has been implicated in psychosis and schizophrenia, and so we looked for genetic association and measured gene expression in human DNA and brain samples, respectively, of the GRIN2B gene that codes for the NR2B protein. We tested three genetic polymorphisms: G-200T (5'UTR), A5806C and T5988C (both 3'UTR) in 180 matched schizophrenia case-control pairs, 86 schizophrenia nuclear family trios, and 318 bipolar disorder trios (of which 158 probands had psychotic symptoms).

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Background And Purpose: Hemodynamics may predispose aneurysms to rupture; however, hemodynamic descriptors that can describe aneurysm growth are not well understood. We examined the relationship between hemodynamics and growth of 2 fusiform basilar artery aneurysms in an effort to define hemodynamic variables that may be helpful in predicting aneurysmal growth.

Methods: Two patients with basilar fusiform aneurysms of a similar size were followed for a 2-year period.

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Schizophrenia (SCZ) is a severe neuropsychiatric disorder with a genetic component. The major inhibitory GABA-(gamma-aminobutyric acid) ergic system may be involved. The GABA type B receptor 1 (GABBR1) gene has been localized to 6p21.

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Objective: Oxidative stress such as free radical-mediated neuronal dysfunction may be involved in the pathophysiology of schizophrenia. The human glutathione peroxidase (GPX1) is a selenium-dependent enzyme, which plays an important role in the detoxification of free radicals. We therefore hypothesized that the GPX1 gene, which is located on chromosome 3p21.

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A number of studies have suggested that the alpha-7-nicotinic receptor D15S1360 polymorphism is associated with schizophrenia and a deficiency in the normal inhibition of the P50 auditory-evoked response. Schizophrenia patients and some of their unaffected relatives show a failure of inhibition in their 50-ms response to the second of a pair of tones. Biochemical studies have suggested that the alpha7 nicotinic acetylcholine receptor is involved in this sensory gating deficit.

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The N-methyl-d-aspartate glutamate receptors (NMDAR) act in the CNS as regulators of the release of neurotransmitters such as dopamine, noradrenaline, acetylcholine, and GABA. It has been suggested that a weakened glutamatergic tone increases the risk of sensory overload and of exaggerated responses in the monoaminergic system, which is consistent with the symptomatology of schizophrenia. We studied two silent polymorphisms in GRIN1.

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