670 Monterey Pass Rd Suite 100
Monterey Park CA 91754
Medical School: Other - Unknown
Accepts Medicare: No
Participates In eRX: No
Participates In PQRS: No
Participates In EHR: No
License #: 32844
Request Appointment Information
Awards & Recognitions
Medical Malpractice Cases
Medical Board Sanctions
Consumer attitudes about the role of multivitamins and other dietary supplements: report of a survey. - Nutrition journal
U.S. nutrition surveys find that intakes of many nutrients fall short of recommendations. The majority of U.S. adults use multivitamins and other dietary supplements as one means of improving nutrient intakes. Some policy makers and health professionals appear reluctant to recommend routine use of dietary supplements to fill nutrient gaps in the diet, in part because they are concerned that people will view the supplements as a substitute for dietary improvement and that the use of supplements may lead to overconsumption of micronutrients. Surveys find that in fact users of dietary supplements tend to have better diets and adopt other healthy habits, suggesting that the supplements are viewed as one aspect of an overall effort to improve wellness. Furthermore, evidence demonstrates that the incidence of excess micronutrient intake is low. We report the results of a survey probing consumer attitudes about the role of dietary supplements.The Council for Responsible Nutrition funded a survey to measure consumer attitudes about the role of multivitamins, calcium and/or vitamin D supplements, and other supplements in improving dietary intakes. The research was designed and analyzed by FoodMinds and was fielded using Toluna's On-line Omnibus. The weighted sample of 2159 respondents is representative of U.S. adults.Nearly 90% of the survey respondents agreed that multivitamins and supplements of calcium and/or vitamin D can help meet nutrient needs when desirable intakes are not achieved through food alone. At the same time, 80% agreed that dietary supplements should not be used to replace healthy dietary or lifestyle habits, and 82% agreed that people considering taking a high dose, single nutrient supplement should talk with their physician.These results provide additional support for the conclusion that the vast majority of consumers recognize that multivitamins and other supplements can help fill nutrient gaps but should not be viewed as replacements for a healthy diet. This suggests that policy makers and health professionals could feel comfortable recommending rational dietary supplementation as one means of improving nutrient intakes, without being unduly concerned that such a recommendation would lead consumers to discount the importance of good dietary habits.
Tumour pharmacodynamics and circulating cell free DNA in patients with refractory colorectal carcinoma treated with regorafenib. - Journal of translational medicine
Regorafenib, a multi-kinase inhibitor, is used in the treatment of patients with metastatic colorectal cancer refractory to standard therapy. However, this benefit was limited to 1.4Â months improvement in overall survival, with more than half of patients experiencing grade 3 to 4 adverse events. We aim to elucidate the pharmacodynamic effects of regorafenib in metastatic colorectal cancer and discover potential biomarkers that may predict clinical benefit.Patients with metastatic colorectal adenocarcinoma refractory to standard therapy with tumours amenable to biopsy were eligible for the study. Regorafenib was administered orally at 160Â mg daily for 3 out of 4Â weeks with tumour assessment every 2Â cycles. Metabolic response was assessed by FDG PET-CT scans (pre-treatment and day 15); paired tumour biopsies (pre-treatment and day 21 post-treatment) were sampled for immunohistochemistry and proteomic profiling analyses. Plasma circulating cell free DNA was quantified serially before and after treatment.There were 2(6%) partial responses out of 35 patients, and 8(23%) patients had stable disease for more than 7Â months. Adverse event profile was similar to reported data. Recurrent somatic mutations in K-RAS, PIK3CA and BRAF were detected in plasma circulating cell free DNA in 14 patients; some mutations were not found in archival tumour. Total plasma circulating cell free DNA inversely correlated with progression free survival (PFS), and presence of KRAS mutations associated with shorter PFS. Immunohistochemistry of pre- and post- treatment biopsies showed majority of patients had downregulation of phosphorylated-VEGFR2, podoplanin, phosphorylated-AKT, Ki-67 and upregulation of the MEK-ERK axis, phosphorylated-C-MET, phosphorylated-SRC, phosphorylated-STAT3 and phosphorylated-JUN. Proteomic analysis of fine needle tumour aspirates showed down-regulation of PI3K was associated with longer PFS.Plasma circulating cell free DNA may yield potential predictive biomarkers of regorafenib treatment. Downregulation of the PI3K-AKT axis may be an important predictor of clinical benefit.
Validation of a rapid and sensitive LC-MS/MS method for determination of exemestane and its metabolites, 17Î²-hydroxyexemestane and 17Î²-hydroxyexemestane-17-O-Î²-D-glucuronide: application to human pharmacokinetics study. - PloS one
A novel, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the evaluation of exemestane pharmacokinetics and its metabolites, 17Î²-dihydroexemestane (active metabolite) and 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide (inactive metabolite) in human plasma. Their respective D3 isotopes were used as internal standards. Chromatographic separation of analytes was achieved using Thermo Fisher BDS Hypersil C18 analytic HPLC column (100 Ã— 2.1 mm, 5 Î¼m). The mobile phase was delivered at a rate of 0.5 mL/min by gradient elution with 0.1% aqueous formic acid and acetonitrile. The column effluents were detected by API 4000 triple quadrupole mass spectrometer using electrospray ionisation (ESI) and monitored by multiple reaction monitoring (MRM) in positive mode. Mass transitions 297 > 121 m/z, 300 > 121 m/z, 299 > 135 m/z, 302 > 135 m/z, 475 > 281 m/z, and 478 > 284 m/z were monitored for exemestane, exemestane-d3, 17Î²-dihydroexemestane, 17Î²-dihydroexemestane-d3, 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide, and 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide-d3 respectively. The assay demonstrated linear ranges of 0.4-40.0 ng/mL, for exemestane; and 0.2-15.0 ng/mL, for 17Î²-dihydroexemestane and 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide, with coefficient of determination (r2) of > 0.998. The precision (coefficient of variation) were â‰¤10.7%, 7.7% and 9.5% and the accuracies ranged from 88.8 to 103.1% for exemestane, 98.5 to 106.1% for 17Î²-dihydroexemestane and 92.0 to 103.2% for 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide. The method was successfully applied to a pharmacokinetics/dynamics study in breast cancer patients receiving exemestane 25 mg daily orally. For a representative patient, 20.7% of exemestane in plasma was converted into 17Î²-dihydroexemestane and 29.0% of 17Î²-dihydroexemestane was inactivated as 17Î²-dihydroexemestane-17-O-Î²-D-glucuronide 24 hours after ingestion of exemestane, suggesting that altered 17-dihydroexemestane glucuronidation may play an important role in determining effect of exemestane against breast cancer cells.
Oxidative decomposition of Au25(SR)18 clusters in a catalytic context. - Chemical communications (Cambridge, England)
Gold nanoparticle catalysis of chemical transformations has emerged as a subject of intense interest over the past decade. In particular, Au25(SR)18 has emerged as a model catalyst. In an effort to investigate their potential as intact, homogeneous, unsupported catalysts, we have discovered that Au25(SR)18 clusters are not stable in oxidizing conditions reported for catalytic styrene oxidation. Further investigation suggests that the active catalytic species is an Au(I) species resulting from oxidative decomposition of the starting gold cluster. This conclusion appears independent of R-group on thiolate-ligated Au25(SR)18 clusters.
Combinatorial discovery of cosolvent systems for production of narrow dispersion thiolate-protected gold nanoparticles. - ACS combinatorial science
The effect of aqueous solvent concentration in the synthesis of water-soluble thiolate-protected gold nanoparticles (AuNPs) was investigated for 13 water-miscible solvents and three thiolate ligands (p-mercaptobenzoic acid, thiomalic acid, and glutathione). The results were analyzed by construction of heat maps that rank each reaction result for polydispersity. When solvents were organized in the heat map according to their Dimroth-Reichardt ET parameter (an approximate measure of polarity), two "hot spots" become apparent that are independent of the ligand used. We speculate that one hot spot may arise in part from the metal chelation or coordination ability of solvents that include diglyme, 1,2-dimethoxyethane, 1,4-dioxane, and tetrahydrofuran. The second hot spot arises at concentrations of alcohols including 2-propanol and 1-butanol that appear to selectively precipitate a growing product, presumably stopping its growth at a certain size. We observe some tightly dispersed products that appear novel. Overall, this study expands the number of tightly dispersed water-soluble AuNPs that can be directly synthesized.
Polymorphism in the innate immune receptor SIRPÎ± controls CD47 binding and autoimmunity in the nonobese diabetic mouse. - Journal of immunology (Baltimore, Md. : 1950)
The signal regulatory protein (SIRP) locus encodes a family of paired receptors that mediate both activating and inhibitory signals and is associated with type 1 diabetes (T1D) risk. The NOD mouse model recapitulates multiple features of human T1D and enables mechanistic analysis of the impact of genetic variations on disease. In this study, we identify Sirpa encoding an inhibitory receptor on myeloid cells as a gene in the insulin-dependent diabetes locus 13.2 (Idd13.2) that drives islet inflammation and T1D. Compared to T1D-resistant strains, the NOD variant of SIRPÎ± displayed greater binding to its ligand CD47, as well as enhanced T cell proliferation and diabetogenic potency. Myeloid cell-restricted expression of a Sirpa transgene accelerated disease in a dose-dependent manner and displayed genetic and functional interaction with the Idd5 locus to potentiate insulitis progression. Our study demonstrates that variations in both SIRPÎ± sequence and expression level modulate T1D immunopathogenesis. Thus, we identify Sirpa as a T1D risk gene and provide insight into the complex mechanisms by which disease-associated variants act in concert to drive defined stages in disease progression.Copyright Â© 2014 by The American Association of Immunologists, Inc.
Chiral phase transfer and enantioenrichment of thiolate-protected Auâ‚â‚€â‚‚ clusters. - Journal of the American Chemical Society
The Au102(p-MBA)44 cluster (p-MBA: para-mercaptobenzoic acid) is observed as a chiral compound comprised of achiral components in its single-crystal structure. So far the enantiomers observed in the crystal structure are not isolated, nor is the circular dichroism spectrum known. A chiral phase transfer method is presented which allows partial resolution of the enantiomers by the use of a chiral ammonium bromide, (-)-1R,2S-N-dodecyl-N-methylephedrinium bromide ((-)-DMEBr). At sufficiently low concentration of (-)-DMEBr, the phase transfer from water to chloroform is incomplete. Both the aqueous and organic phases show optical activity of near mirror image relationship. Differences in the spectra are ascribed to the formation of diastereomeric salts. At high concentrations of (-)-DMEBr, full phase transfer is observed. The organic phase, however, still displays optical activity. We assume that one of the diastereomers has very strong optical activity, which overrules the cancelation of the spectra with opposite sign. Comparison with computations further corroborates the experimental data and allows a provisional assignment of handedness of each fraction.
Analyses of Ca2+ accumulation and dynamics in the endoplasmic reticulum of Arabidopsis root cells using a genetically encoded Cameleon sensor. - Plant physiology
In planta, very limited information is available about how the endoplasmic reticulum (ER) contributes to cellular Ca(2+) dynamics and homeostasis. Here, we report the generation of an ER-targeted Cameleon reporter protein suitable for analysis of Ca(2+) accumulation and dynamics in the lumen of the ER in plant cells. Using stably transformed Arabidopsis (Arabidopsis thaliana) plants expressing this reporter protein, we observed a transiently enhanced accumulation of Ca(2+) in the ER in response to stimuli inducing cytosolic Ca(2+) rises in root tip cells. In all experimental conditions, ER Ca(2+) dynamics were substantially different from those monitored in the cytosol. A pharmacological approach enabled us to evaluate the contribution of the different ER-resident Ca(2+)-ATPase classes in the regulation of the ER Ca(2+) homeostasis. Taken together, our results do not provide evidence for a role of the ER as a major source that releases Ca(2+) for stimulus-induced increases in cytosolic Ca(2+) concentration. Instead, our results show that the luminal ER Ca(2+) elevations typically follow cytosolic ones, but with distinct dynamics. These findings suggest fundamental differences for the function of the ER in cellular Ca(2+) homeostasis in plants and animals.
Structure-activity relationships for biodistribution, pharmacokinetics, and excretion of atomically precise nanoclusters in a murine model. - Nanoscale
The absorption, distribution, metabolism and excretion (ADME) and pharmacokinetic (PK) properties of inorganic nanoparticles with hydrodynamic diameters between 2 and 20 nm are presently unpredictable. It is unclear whether unpredictable in vivo properties and effects arise from a subset of molecules in a nanomaterials preparation, or if the ADME/PK properties are ensemble properties of an entire preparation. Here we characterize the ADME/PK properties of atomically precise preparations of ligand protected gold nanoclusters in a murine model system. We constructed atomistic models and tested in vivo properties for five well defined compounds, based on crystallographically resolved Au25(SR)18 and Au102(SR)44 nanoclusters with different (SR) ligand shells. To rationalize unexpected distribution and excretion properties observed for several clusters in this study and others, we defined a set of atomistic structure-activity relationships (SAR) for nanoparticles, which includes previously investigated parameters such as particle hydrodynamic diameter and net charge, and new parameters such as hydrophobic surface area and surface charge density. Overall we find that small changes in particle formulation can provoke dramatic yet potentially predictable changes in ADME/PK.
Heterogeneity of Ca2+ handling among and within Golgi compartments. - Journal of molecular cell biology
The Golgi apparatus (GA) is a dynamic intracellular Ca(2+) store endowed with complex Ca(2+) homeostatic mechanisms in part distinct from those of the endoplasmic reticulum (ER). We describe the generation of a novel fluorescent Ca(2+) probe selectively targeted to the medial-Golgi. We demonstrate that in the medial-Golgi: (i) Ca(2+) accumulation takes advantage of two distinct pumps, the sarco/endoplasmic reticulum Ca(2+) ATPase and the secretory pathway Ca(2+) ATPase1; (ii) activation of IP3 or ryanodine receptors causes Ca(2+) release, while no functional two-pore channel was found; (iii) luminal Ca(2+) concentration appears higher than that of the trans-Golgi, but lower than that of the ER, suggesting the existence of a cis- to trans-Golgi Ca(2+) concentration gradient. Thus, the GA represents a Ca(2+) store of high complexity where, despite the continuous flow of membranes and luminal contents, each sub-compartment maintains its Ca(2+) identity with specific Ca(2+) homeostatic characteristics. The functional role of such micro-heterogeneity in GA Ca(2+) handling is discussed.
Map & Directions
670 Monterey Pass Rd Suite 100 Monterey Park, CA 91754
1900 S Atlantic Blvd Suite 3
500 N Garfield Ave 100
223 N Garfield Ave Ste 305
1900 S Atlantic Blvd Ste 3
500 N Garfield Ave Ste 108