Publications by authors named "Steven Nguyen"

44 Publications

A human ESC-based screen identifies a role for the translated lncRNA in pancreatic endocrine differentiation.

Elife 2020 08 3;9. Epub 2020 Aug 3.

Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, San Diego, United States.

Long noncoding RNAs (lncRNAs) are a heterogenous group of RNAs, which can encode small proteins. The extent to which developmentally regulated lncRNAs are translated and whether the produced microproteins are relevant for human development is unknown. Using a human embryonic stem cell (hESC)-based pancreatic differentiation system, we show that many lncRNAs in direct vicinity of lineage-determining transcription factors (TFs) are dynamically regulated, predominantly cytosolic, and highly translated. We genetically ablated ten such lncRNAs, most of them translated, and found that nine are dispensable for pancreatic endocrine cell development. However, deletion of diminishes insulin cells, in a manner independent of the nearby TF . One-by-one disruption of each of 's open reading frames suggests that the RNA, rather than the produced microproteins, is required for endocrine development. Our work highlights extensive translation of lncRNAs during hESC pancreatic differentiation and provides a blueprint for dissection of their coding and noncoding roles.
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http://dx.doi.org/10.7554/eLife.58659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423336PMC
August 2020

Selective inhibition of peripheral cathepsin S reverses tactile allodynia following peripheral nerve injury in mouse.

Eur J Pharmacol 2020 Aug 11;880:173171. Epub 2020 May 11.

Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA, 92121, USA.

Cathepsin S (CatS) is a cysteine protease found in lysosomes of hematopoietic and microglial cells and in secreted form in the extracellular space. While CatS has been shown to contribute significantly to neuropathic pain, the precise mechanisms remain unclear. In this report, we describe JNJ-39641160, a novel non-covalent, potent, selective and orally-available CatS inhibitor that is peripherally restricted (non-CNS penetrant) and may represent an innovative class of immunosuppressive and analgesic compounds and tools useful toward investigating peripheral mechanisms of CatS in neuropathic pain. In C57BL/6 mice, JNJ-39641160 dose-dependently blocked the proteolysis of the invariant chain, and inhibited both T-cell activation and antibody production to a vaccine antigen. In the spared nerve injury (SNI) model of chronic neuropathic pain, in which T-cell activation has previously been demonstrated to be a prerequisite for the development of pain hypersensitivity, JNJ-39641160 fully reversed tactile allodynia in wild-type mice but was completely ineffective in the same model in CatS knockout mice (which exhibited a delayed onset in allodynia). By contrast, in the acute mild thermal injury (MTI) model, JNJ-39641160 only weakly attenuated allodynia at the highest dose tested. These findings support the hypothesis that blockade of peripheral CatS alone is sufficient to fully reverse allodynia following peripheral nerve injury and suggest that the mechanism of action likely involves interruption of T-cell activation and peripheral cytokine release. In addition, they provide important insights toward the development of selective CatS inhibitors for the treatment of neuropathic pain in humans.
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http://dx.doi.org/10.1016/j.ejphar.2020.173171DOI Listing
August 2020

Cross-reactive carbohydrate determinant interference in cellulose-based IgE allergy tests utilizing recombinant allergen components.

PLoS One 2020 23;15(4):e0231344. Epub 2020 Apr 23.

Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.

Background: Cross-reactive carbohydrate determinant (CCD) structures found in plant and insect glycoproteins are commonly recognized by IgE antibodies as epitopes that can lead to extensive cross-reactivity and obscure in vitro diagnostic (IVD) serology results. With the introduction of component resolved diagnosis (CRD), recombinant non-glycosylated components have been utilized to mitigate the risk of CCD-specific IgE (sIgE) detection. However, a recent study has shown that CCD-sIgE may bind directly to the cellulose solid phase matrix used in certain in vitro diagnostic assays, eliminating the advantage of CRD over traditional extract-based testing. The aim of this study is to further investigate the prevalence of CCD-sIgE interference on a commonly-used in vitro sIgE automated platform which employs a cellulose-based matrix to immobilize CCD-free recombinant components.

Methods: Sera from patients sensitized to peanut, silver birch, and/or timothy grass were analyzed for CCD-sIgE reactivity on ImmunoCAP/Phadia and NOVEOS autoanalyzers against the MUXF3 carbohydrate component. Positive CCD-sIgE sera were further analyzed against non-glycosylated recombinant components bound to the ImmunoCAP solid phase in the absence and presence of a soluble CCD inhibitor. For comparison, sera were then analyzed on NOVEOS, a non-cellulose based automated sIgE assay.

Results: Sera from 35% of the sensitized population tested in this study were positive (≥0.35 kU/L) for CCD-sIgE. Of those positives, 17% resulted in CCD-sIgE-positive (false positive) results on ImmunoCAP using non-glycosylated allergosorbents that were negative on NOVEOS. Sera producing false-positive results on ImmunoCAP had varying levels of CCD-sIgE from 0.67 kU/L to 36.52 kU/L. The incidence of CCD interference was predominantly delimited to low-positive IgE results (0.35 kUA/L- 3.00 kUA/L).

Conclusion: Falsely elevated diagnostic allergen-sIgE results can commonly occur due to the presence of CCD-sIgE using assays that employ a carbohydrate matrix-based allergosorbent. Even the use of non-glycosylated recombinant allergenic components coupled to cellulose matrices do not reduce their risk of detection. The risk of CCD interference that compromises quantitative IgE results can be mitigated by the addition of a soluble CCD inhibitor to positive CCD-sIgE containing sera or by alternatively using a non-cellulose based sIgE assay, such as the NOVEOS assay.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231344PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179882PMC
July 2020

Association of Mineral Bone Disorder With Decline in Residual Kidney Function in Incident Hemodialysis Patients.

J Bone Miner Res 2020 02 30;35(2):317-325. Epub 2019 Oct 30.

Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California Irvine Medical Center, Orange, CA, USA.

Abnormalities of mineral bone disorder (MBD) parameters have been suggested to be associated with poor renal outcome in predialysis patients. However, the impact of those parameters on decline in residual kidney function (RKF) is uncertain among incident hemodialysis (HD) patients. We performed a retrospective cohort study in 13,772 patients who initiated conventional HD during 2007 to 2011 and survived 6 months of dialysis. We examined the association of baseline serum phosphorus, calcium, intact parathyroid hormone (PTH), and alkaline phosphatase (ALP) with a decline in RKF. Decline in RKF was assessed by estimated slope of renal urea clearance (KRU) over 6 months from HD initiation. Our cohort had a mean ± SD age of 62 ± 15 years; 64% were men, 57% were white, 65% had diabetes, and 51% had hypertension. The median (interquartile range [IQR]) baseline KRU level was 3.4 (2.0, 5.2) mL/min/1.73 m . The median (IQR) estimated 6-month KRU slope was -1.47 (-2.24, -0.63) mL/min/1.73 m per 6 months. In linear regression models, higher phosphorus categories were associated with a steeper 6-month KRU slope compared with the reference category (phosphorus 4.0 to <4.5 mg/dL). Lower calcium and higher intact PTH and ALP categories were also associated with a steeper 6-month KRU slope compared with their respective reference groups (calcium 9.2 to <9.5 mg/dL; intact PTH 150 to <250 pg/mL; ALP <60 U/L). The increased number of parameter abnormalities had an additive effect on decline in RKF. Abnormalities of MBD parameters including higher phosphorus, intact PTH, ALP and lower calcium levels were independently associated with decline in RKF in incident HD patients. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.
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http://dx.doi.org/10.1002/jbmr.3893DOI Listing
February 2020

Molecular Mechanisms of Intranasal Insulin in SAMP8 Mice.

J Alzheimers Dis 2019 ;71(4):1361-1373

Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA.

Research on intranasal delivery of drugs, peptides, and proteins has grown over the past decade as an alternate way to deliver substrates to the brain. Recent work has shown intranasal (INL) delivery of insulin improves memory and cognition in healthy subjects as well as patients with Alzheimer's disease (AD) and in AD mouse models. However, the molecular mechanism(s) for the beneficial effect of insulin on memory are still unclear. Using the SAMP8 mouse model of AD, we investigated the impact of INL insulin on protein and gene expression in brain regions including the olfactory bulb, hypothalamus, and hippocampus. We found genes and proteins in the insulin receptor signaling pathway were not activated by the doses tested. However, we did find the expression of genes present in the hippocampus involved in other pathways, especially those related to inflammation, were altered due to age and with a dose of INL insulin previously shown to improve cognition. These alternate pathways could be targets of insulin when delivered via the INL route to aid in memory improvement.
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http://dx.doi.org/10.3233/JAD-190707DOI Listing
November 2020

Cutaneous Branch of the Obturator Nerve Extending to the Medial Ankle and Foot: A Report of Two Cadaveric Cases.

J Foot Ankle Surg 2019 Nov 23;58(6):1267-1272. Epub 2019 Jul 23.

Associate Professor, Department of Anatomy, Western University of Health Sciences College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine, Pomona, CA.

The area of skin supplied by the cutaneous branch of the obturator nerve (CBO) is highly variable. Although most introductory anatomy texts describe the CBO as innervating only a portion of the medial thigh, there are numerous reports in the literature of CBOs passing the knee to innervate the proximal, middle, or even distal leg. There are no previous reports of CBOs extending to the ankle and foot. Herein we describe 2 cases of CBOs extending at least to the medial foot. Both cases were discovered incidentally, during routine cadaver dissections by osteopathic and podiatric medical students in the anatomy laboratory of Western University of Health Sciences in California. In both instances, the anomalously long CBOs shared several characteristics: (1) they arose as direct branches of the anterior division of the obturator nerve, not from the subsartorial plexus; (2) they coursed immediately posterior to the great saphenous vein from the distal thigh to the distal leg, only deviating away from the saphenous vein just above the medial malleolus; and (3) they terminated in radiating fibers to the posterior half of the medial ankle and foot. In both cases, the saphenous branch of the femoral nerve was present but restricted to the area anterior to the great saphenous vein. It is likely that the variant CBOs carried fibers of the L4 spinal nerve and thus provided cutaneous innervation to the medial foot and ankle, a function most commonly reserved for the saphenous branch of the femoral nerve distal to the knee. Saphenous neuropathy is a common postoperative complication of saphenous cutdowns for coronary artery bypass grafts, so the potential involvement of a long CBO can add additional complexity to regional anesthetic blocks for foot and ankle surgery and procedures such as vein harvesting for coronary artery bypass grafts.
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http://dx.doi.org/10.1053/j.jfas.2019.03.007DOI Listing
November 2019

Tripeptide analogues of MG132 as protease inhibitors.

Bioorg Med Chem 2019 01 14;27(2):436-441. Epub 2018 Dec 14.

Department of Chemistry, and Centre for Nanoscale BioPhotonics (CNBP), University of Adelaide, Adelaide, South Australia 5005, Australia.

The 26S proteasome and calpain are linked to a number of important human diseases. Here, we report a series of analogues of the prototypical tripeptide aldehyde inhibitor MG132 that show a unique combination of high activity and selectivity for calpains over proteasome. Tripeptide aldehydes (1-3) with an aromatic P3 substituent show enhanced activity and selectivity against ovine calpain 2 relative to chymotrypsin-like activity of proteasome. Docking studies reveal the key contacts between inhibitors and calpain to confirm the importance of the S3 pocket with respect to selectivity between calpains 1 and 2 and the proteasome.
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http://dx.doi.org/10.1016/j.bmc.2018.12.022DOI Listing
January 2019

Lens Dose-Response Prediction Modeling and Cataract Incidence in Patients With Retinoblastoma After Lens-Sparing or Whole-Eye Radiation Therapy.

Int J Radiat Oncol Biol Phys 2019 04 8;103(5):1143-1150. Epub 2018 Dec 8.

Department of Radiation Oncology, Keck School of Medicine of USC and Children's Hospital Los Angeles, Los Angeles, California. Electronic address:

Purpose: We retrospectively assessed the incidence of cataracts in patients with retinoblastoma (Rb) treated with either lens-sparing radiation therapy (LSRT) or whole-eye radiation therapy (WERT). A secondary aim of this study was to model the dose-response risk of cataract.

Methods And Materials: We reviewed 65 patients with Rb treated with radiation therapy (RT) at Children's Hospital, Los Angeles from 1997 to 2015. Eyes that were enucleated before RT or lacked follow-up eye examinations were excluded. All patients underwent computed tomography simulation, and mean lens dose data were collected. Follow-up ophthalmologic examinations and intraocular lens implant history were reviewed for cataracts. The primary event-free survival (EFS) outcome was cataract development. Eyes without cataracts were censored on the last date of eye examination or post-RT enucleation, if applicable. Kaplan-Meier estimates were used to compare EFS outcomes, and dose response was projected with Cox regression and logistic regression models.

Results: Sixty-one patients (94 eyes) were analyzed with a median follow-up of 51.8 months. For eyes treated with WERT, cataracts developed in 71.7% versus 35.3% for LSRT. Median EFS for WERT and LSRT were 20.8 and 67.9 months, respectively. Compared with WERT, a significant EFS benefit was demonstrated for LSRT (P < .001). Mean lens dose had a significant effect on cataracts in both Cox regression and logistic regression models (P < .01). The mean lens dose of 7 Gy was projected to have a 5-year cataract incidence of 20% and 25% with the logistic and Cox regression models, respectively.

Conclusions: We report the first clinical data demonstrating significantly improved EFS in patients with Rb treated with LSRT. Through lens dose-response modeling, we validate a mean lens dose threshold of 7 Gy to keep cataract risk below 25%. Although RT is used less often for Rb owing to advances in chemotherapy delivery options, these findings are relevant for refining lens dose constraints, particularly in children who have received radiation dose near the orbit.
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http://dx.doi.org/10.1016/j.ijrobp.2018.12.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6667833PMC
April 2019

Emergency Department and Primary Care Use by Refugees Compared to Non-refugee Controls.

J Immigr Minor Health 2019 Aug;21(4):793-800

Developmental Pediatrics, University of Virginia Children's Hospital, Charlottesville, VA, USA.

The U.S. grants asylum to 60,000-70,000 refugees yearly. However, little is known about their healthcare utilization practices. We examined data from emergency department (ED) and primary care (PC) visits of 694 refugees and 738 non-refugee controls over a 3 years period at a large academic medical center, comparing visit frequencies, Emergency Severity Index (ESI) scores, diagnoses, and dispositions. Refugees used emergency care services less frequently than the non-refugee controls (1.19 vs. 2.31, p < 0.0001) while there was no difference in their use of primary care services (8.45 vs. 9.07, p = 0.18). Non-English-speaking refugees were more likely to use the ED than English-speaking refugees (mean ED use in study period 1.50 visits vs. 0.73, p < 0.0001). Refugee patients utilized emergency services less often compared to controls. These results differ from previously studied refugee populations. Refugee-specific primary care services in this study population may reduce unnecessary ED use.
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http://dx.doi.org/10.1007/s10903-018-0795-5DOI Listing
August 2019

Collision Risk Mitigation of Varian TrueBeam Linear Accelerator With Supplemental Live-View Cameras.

Pract Radiat Oncol 2019 Jan 12;9(1):e103-e109. Epub 2018 Jul 12.

Children's Hospital Los Angeles, Los Angeles, California; Department of Radiation Oncology, Keck School of Medicine, USC, Los Angeles, California.

Background: Noncoplanar radiation therapy techniques such as 4π have potential dosimetric advantages but introduce complexities in treatment delivery that increase the risk for collision. Direct or remote visual confirmation of clearance is a safeguard against collisions of the gantry, couch, and patient. With our institution's Varian TrueBeam system, we identified configurations that cannot be visualized with the included closed-circuit television cameras. At our practice, electronic, portal imaging device (EPID) collision risk also exists because of the routine deployment to capture exit-dose images for treatment quality assurance. We propose a simple, cost-effective solution using network cameras to help eliminate blind spots that permits safe, noncoplanar arrangements with an EPID-acquired exit dose.

Methods And Materials: Two Panasonic cameras were installed overhead while a third Panasonic camera was mounted onto the pedestal to monitor the couch undersurface. Live views from each camera were accessed with a web-based client. The EPID and gantry were visually assessed at 52 couch and gantry rotational angle configurations at 6 couch translational positions. Visibility was compared for the standard and supplemental camera setups at each configuration (χ test).

Results: Of the 294 assessable couch-gantry configurations, the standard camera setup had limited visibility of either gantry or EPID for 146 configurations compared with 72 configurations with additional cameras (51% blind-spot reduction; P < .01). An 87% blind-spot reduction was observed for our laterally centered, cranial-based, couch translational position (P < .01).

Conclusions: The supplemental cameras were simple, effective additions for collision detection, especially for noncoplanar radiation therapy with EPID-acquired, exit-dose imaging. Over half of the assessable noncoplanar configurations had blind spots using standard cameras, which was reduced to <25% with additional cameras. In practice, there were almost no blind spots for patients with brain tumors who were treated with our templated beam arrangements. Using live-view camera feeds, vault re-entry to visually confirm clearance was reduced approximately 10-fold, which increased the treatment efficiency. In the most recent 12 months, no collision or near-collision events have been reported.
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http://dx.doi.org/10.1016/j.prro.2018.07.001DOI Listing
January 2019

Nonalcoholic Fatty Liver Disease.

Prim Care 2017 Dec;44(4):599-607

Family Medicine Residency in Palm Springs, University of California, Riverside, 555 Tachevah Drive, 2E-204, Palm Springs, CA 92262, USA.

Nonalcoholic fatty liver disease (NAFLD) defines a condition of hepatic steatosis with or without hepatic injury. NAFLD is increasing in prevalence worldwide and presents a public health burden. Most patients are asymptomatic, although some present with fatigue and right upper quadrant pain. NAFLD is discovered incidentally when patients have elevated liver enzymes or fatty liver is seen on imaging modalities. Imaging studies can confirm fatty deposits in the liver, but needle biopsy is needed to determine degree of inflammation. The mainstay of treatment is weight loss and controlling diabetes and hyperlipidemia. Liver transplantation is considered when disease progresses to cirrhosis.
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http://dx.doi.org/10.1016/j.pop.2017.07.003DOI Listing
December 2017

Evaluation of weekly paclitaxel plus carboplatin followed by anthracycline chemotherapy on the neoadjuvant treatment of patients with triple-negative breast cancer.

Hematol Oncol Stem Cell Ther 2018 Mar 28;11(1):30-33. Epub 2017 Oct 28.

Medical Oncology-Hematology, Memorial Cancer Institute, Herbert Wertheim College of Medicine, Florida International University, United States.

Objective: To evaluate the effectiveness and tolerability of neoadjuvant chemotherapy with weekly paclitaxel in combination with weekly carboplatin area under curve 2 followed by anthracycline chemotherapy.

Patients And Methods: This is a retrospective review of electronic medical records of patients (N = 32) with stage 1c-III triple-negative breast cancer. Patients received neoadjuvant chemotherapy with paclitaxel 80 mg/m once per week for 12 weeks in combination with carboplatin area under curve 2 once per week for 12 weeks (wP + wCb), followed by a standard anthracycline regimen including either doxorubicin 60 mg/m and cyclophosphamide 600 mg/m every 2 or 3 weeks, or epirubicin 90 mg/m and cyclophosphamide 600 mg/m every 3 weeks for four cycles with myeloid growth factor support.

Results: Most patients (91%) received all 12 cycles of wP + wCb, and 88% received all four planned cycles of anthracycline chemotherapy. Of the patients, 84% completed all planned therapies. The complete pathologic response rate was 60%. In terms of hematologic toxicity, 96% of the patients experienced grade ≥3 leucopenia, 40% grade ≥3 anemia, and 15% grade ≥3 thrombocytopenia, and neutropenic fever was seen in 22% of the patients.

Conclusion: The combination of neoadjuvant chemotherapy with wP + wCb before anthracycline chemotherapy can be tolerated by patients with triple-negative breast cancer. Complete pathologic response rates were comparable with those historically seen. Careful selection of patients is fundamental as this regimen is associated with a high incidence of hematologic toxicity.
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http://dx.doi.org/10.1016/j.hemonc.2017.07.006DOI Listing
March 2018

Pulmonary Embolism Secondary to Testosterone-Enhancing Herbal Supplement Use.

Cureus 2017 Aug 6;9(8):e1545. Epub 2017 Aug 6.

Medicine, Orlando VAMC.

Decreased testosterone levels in men are often a normal sign of aging. Testosterone replacement therapy (TRT) is a well-established option for those with symptomatic hypogonadism related to low testosterone levels. Conversely, designer herbal supplements in the context of testosterone supplementation are poorly studied, yet remain popular among aging men who seek the well-known, often enhancing, effects of testosterone that involve muscle mass and sexual function/drive. In 2014, the Food and Drug Administration (FDA) issued a warning about the significant risk of venous clots secondary to testosterone product use. Testosterone-induced polycythemia is one of the proposed mechanisms for this increased clotting propensity. Increased thromboxane A2 receptor density on platelets and increased platelet aggregation have also been linked to testosterone treatment in men. Fenugreek extract is a common active ingredient in commercially available herbal supplements that are often marketed as testosterone enhancers. It is thought that certain fenugreek compounds inhibit aromatase and 5-alpha-reductase activity, leading to diminished testosterone breakdown. However, the efficacy and safety profile of this agent in its use for boosting testosterone levels are unclear. In this case report, we present a patient with new-onset, bilateral pulmonary embolism possibly associated with the daily use of fenugreek-containing testosterone supplements.
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http://dx.doi.org/10.7759/cureus.1545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5630464PMC
August 2017

Eleclazine exhibits enhanced selectivity for long QT syndrome type 3-associated late Na current.

Heart Rhythm 2018 02 7;15(2):277-286. Epub 2017 Oct 7.

Department of Biology, Gilead Sciences, Inc., Fermont, California. Electronic address:

Background: Eleclazine (GS-6615) is a sodium channel blocker designed to improve the selectivity for cardiac late Na current (I) over peak I.

Objectives: The goals of this study were to investigate the inhibition of late I by eleclazine using a sample of long QT syndrome type 3 (LQT3) and overlap LQT3/Brugada syndrome mutant channels; to compare the apparent binding rates for eleclazine with those for other class 1 antiarrhythmic agents; and to investigate the binding site.

Methods: Wild-type human cardiac voltage-gated sodium channel (hNa1.5) and 21 previously reported variants were studied using patch clamp recordings from a heterologous expression system.

Results: Eleclazine inhibited anemone toxin II-enhanced late I from wild-type hNa1.5 with a drug concentration that causes 50% block of 0.62 ± 0.12 μM (84-fold selectivity over peak I). The drug concentration that causes 50% block of eleclazine to inhibit the enhanced late I from LQT3 mutant channels ranged from 0.33 to 1.7 μM. At predicted therapeutic concentrations, eleclazine and ranolazine inhibited peak I to a similar degree as assessed with 4 overlap LQT3/Brugada syndrome mutations. Eleclazine was found to interact with hNa1.5 significantly faster than ranolazine and 6 other class 1 antiarrhythmic agents. Engineered mutations (F1760A/Y1767A) located within the local anesthetic binding site decreased the inhibition of late I and peak I by eleclazine.

Conclusion: At predicted therapeutic concentrations, eleclazine elicits potent inhibition of late I across a cohort of Na1.5 mutant channels. These properties are consistent with a class 1b antiarrhythmic agent that associates with unusually rapid binding/unbinding rates.
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http://dx.doi.org/10.1016/j.hrthm.2017.09.028DOI Listing
February 2018

Stereotactic Radiosurgery and Ipilimumab Versus Stereotactic Radiosurgery Alone in Melanoma Brain Metastases.

Cureus 2017 Jul 25;9(7):e1511. Epub 2017 Jul 25.

Department of Computer Science, University of Houston.

Benefits of stereotactic radiosurgery (SRS) have been well established in melanoma brain metastases (MBM). Immunotherapy agents such as ipilimumab (ipi) have recently demonstrated clinical efficacy in advanced disease as well. The theoretical synergistic effects of combining these therapies in MBM have not been explored in detail, however, we conducted a systematic review with meta-analysis of studies that compared combined SRS and ipi versus SRS alone in MBM. Medical Literature Analysis and Retrieval System Online (MEDLINE) and Central databases were used for our literature search, which was conducted by three reviewers. We included studies that examined SRS and ipilimumab compared to SRS alone in MBM. Pertinent results were tabulated in a standardized spreadsheet. Newcastle-Ottawa Scale (NOS) Risk of Bias Assessment and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) method for rating evidence quality were used for qualitative analysis. Review Manager was used for statistical analysis. We identified four cohort studies that compared SRS plus ipi versus SRS alone in MBM. As per the GRADE criteria, we found low-quality evidence for survival benefits associated with combined treatment. Meta-analysis confirmed a significant benefit in survival for SRS and ipilimumab (hazard ratio 0.38, 95% confidence interval 0.28 - 0.52, p < 0.01). There were no significant differences between comparison groups for local control, distant brain control, radiation necrosis, or intracranial bleeding. We conclude that low-quality evidence exists for superior overall survival in MBM treated with SRS and ipilimumab compared to SRS without ipilimumab. There is also no increased risk of radiation necrosis and/or intracranial bleeding with combining radiation and immunotherapy in this setting.
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http://dx.doi.org/10.7759/cureus.1511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5612568PMC
July 2017

Impressive Response to Concomitant Platinum-based Chemotherapy and Yttrium-90 in a Patient with Heavily Pretreated Triple-negative Breast Cancer Widely Metastasized to the Liver.

Cureus 2017 Jun 28;9(6):e1402. Epub 2017 Jun 28.

Medical Oncology and Hematology, Memorial Cancer Institute.

Metastatic triple-negative breast cancer (TNBC) constitutes a heterogeneous group of diseases with systemic treatment options limited to cytotoxic chemotherapy at the time being. The disease tends to affect visceral organs more frequently when compared to hormone receptor-positive breast cancer. The prognoses of patients with heavily pretreated disease affecting the liver are very dismal. We present the response to radioembolization and systemic chemotherapy in a seriously ill patient who had undergone previous lines of chemotherapy for TNBC with extensive liver metastases.
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http://dx.doi.org/10.7759/cureus.1402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5573050PMC
June 2017

LC/MS/MS Profiling of Tissue Oxysterols and its Application in Dextran Sodium Sulphate Induced Mouse Colitis Models.

Curr Top Med Chem 2017 ;17(24):2781-2790

Janssen R&D, LLC., 3210 Merryfield Row, San Diego, CA 92121. United States.

We have developed a workflow to extract, separate, and semi-quantify bioactive oxysterols from mouse colon tissues and fecal matters using solid- and liquid-phase extractions, enzymatic and chemical modifications, and stable-isotope dilution LC/MS/MS. The method was applied to a dextran sodium sulphate (DSS)-induced mouse colitis model, which revealed that one particular dihydroxycholesterol (diOHC), 7α,25-diOHC, was significantly elevated in both colon tissue and fecal matters of mice with colitis compared to that in naïve mice. The extent of 7α,25-diOHC elevation was positively correlated with colitis severity.
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http://dx.doi.org/10.2174/1568026617666170713165519DOI Listing
September 2017

A novel AhR ligand, 2AI, protects the retina from environmental stress.

Sci Rep 2016 07 1;6:29025. Epub 2016 Jul 1.

Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94901, USA.

Various retinal degenerative diseases including dry and neovascular age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy are associated with the degeneration of the retinal pigmented epithelial (RPE) layer of the retina. This consequently results in the death of rod and cone photoreceptors that they support, structurally and functionally leading to legal or complete blindness. Therefore, developing therapeutic strategies to preserve cellular homeostasis in the RPE would be a favorable asset in the clinic. The aryl hydrocarbon receptor (AhR) is a conserved, environmental ligand-dependent, per ARNT-sim (PAS) domain containing bHLH transcription factor that mediates adaptive response to stress via its downstream transcriptional targets. Using in silico, in vitro and in vivo assays, we identified 2,2'-aminophenyl indole (2AI) as a potent synthetic ligand of AhR that protects RPE cells in vitro from lipid peroxidation cytotoxicity mediated by 4-hydroxynonenal (4HNE) as well as the retina in vivo from light-damage. Additionally, metabolic characterization of this molecule by LC-MS suggests that 2AI alters the lipid metabolism of RPE cells, enhancing the intracellular levels of palmitoleic acid. Finally, we show that, as a downstream effector of 2AI-mediated AhR activation, palmitoleic acid protects RPE cells from 4HNE-mediated stress, and light mediated retinal degeneration in mice.
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http://dx.doi.org/10.1038/srep29025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929558PMC
July 2016

Contribution of the late sodium current to intracellular sodium and calcium overload in rabbit ventricular myocytes treated by anemone toxin.

Am J Physiol Heart Circ Physiol 2016 Feb 4;310(3):H426-35. Epub 2015 Dec 4.

Department of Biology, Gilead Sciences Inc., Foster City, California.

Pathological enhancement of late Na(+) current (INa) can potentially modify intracellular ion homeostasis and contribute to cardiac dysfunction. We tested the hypothesis that modulation of late INa can be a source of intracellular Na(+) ([Na(+)]i) overload. Late INa was enhanced by exposing rabbit ventricular myocytes to Anemonia sulcata toxin II (ATX-II) and measured using whole cell patch-clamp technique. [Na(+)]i was determined with fluorescent dye Asante NaTRIUM Green-2 AM. Pacing-induced changes in the dye fluorescence measured at 37°C were more pronounced in ATX-II-treated cells than in control (dye washout prevented calibration). At 22-24°C, resting [Na(+)]i was 6.6 ± 0.8 mM. Treatment with 5 nM ATX-II increased late INa 8.7-fold. [Na(+)]i measured after 2 min of electrical stimulation (1 Hz) was 10.8 ± 1.5 mM and 22.1 ± 1.6 mM (P < 0.001) in the absence and presence of 5 nM ATX-II, respectively. Inhibition of late INa with GS-967 (1 μM) prevented Na(+) i accumulation. A strong positive correlation was observed between the late INa and the pacing-induced increase of [Na(+)]i (R(2) = 0.88) and between the rise in [Na(+)]i and the increases in cytosolic Ca(2+) (R(2) = 0.96). ATX-II, tetrodotoxin, or GS-967 did not affect [Na(+)]i in quiescent myocytes suggesting that late INa was solely responsible for triggering the ATX-II effect on [Na(+)]i. Experiments with pinacidil and E4031 indicate that prolongation of the action potential contributes to as much as 50% of the [Na(+)]i overload associated with the increase in late INa caused by ATX-II. Enhancement of late INa can cause intracellular Na(+) overload in ventricular myocytes.
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http://dx.doi.org/10.1152/ajpheart.00520.2015DOI Listing
February 2016

Oxysterols are agonist ligands of RORγt and drive Th17 cell differentiation.

Proc Natl Acad Sci U S A 2014 Aug 4;111(33):12163-8. Epub 2014 Aug 4.

Janssen Research and Development, Spring House, PA 19002.

The RAR-related orphan receptor gamma t (RORγt) is a nuclear receptor required for generating IL-17-producing CD4(+) Th17 T cells, which are essential in host defense and may play key pathogenic roles in autoimmune diseases. Oxysterols elicit profound effects on immune and inflammatory responses as well as on cholesterol and lipid metabolism. Here, we describe the identification of several naturally occurring oxysterols as RORγt agonists. The most potent and selective activator for RORγt is 7β, 27-dihydroxycholesterol (7β, 27-OHC). We show that these oxysterols reverse the inhibitory effect of an RORγt antagonist, ursolic acid, in RORγ- or RORγt-dependent cell-based reporter assays. These ligands bind directly to recombinant RORγ ligand binding domain (LBD), promote recruitment of a coactivator peptide, and reduce binding of a corepressor peptide to RORγ LBD. In primary cells, 7β, 27-OHC and 7α, 27-OHC enhance the differentiation of murine and human IL-17-producing Th17 cells in an RORγt-dependent manner. Importantly, we showed that Th17, but not Th1 cells, preferentially produce these two oxysterols. In vivo, administration of 7β, 27-OHC in mice enhanced IL-17 production. Mice deficient in CYP27A1, a key enzyme in generating these oxysterols, showed significant reduction of IL-17-producing cells, including CD4(+) and γδ(+) T cells, similar to the deficiency observed in RORγt knockout mice. Our results reveal a previously unknown mechanism for selected oxysterols as immune modulators and a direct role for CYP27A1 in generating these RORγt agonist ligands, which we propose as RORγt endogenous ligands, driving both innate and adaptive IL-17-dependent immune responses.
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http://dx.doi.org/10.1073/pnas.1322807111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143045PMC
August 2014

Vectored immunoprophylaxis protects humanized mice from mucosal HIV transmission.

Nat Med 2014 Mar 9;20(3):296-300. Epub 2014 Feb 9.

Division of Biology, California Institute of Technology, Pasadena, California, USA.

The vast majority of new HIV infections result from relatively inefficient transmission of the virus across mucosal surfaces during sexual intercourse. A consequence of this inefficiency is that small numbers of transmitted founder viruses initiate most heterosexual infections. This natural bottleneck to transmission has stimulated efforts to develop interventions that are aimed at blocking this step of the infection process. Despite the promise of this strategy, clinical trials of preexposure prophylaxis have had limited degrees of success in humans, in part because of lack of adherence to the recommended preexposure treatment regimens. In contrast, a number of existing vaccines elicit systemic immunity that protects against mucosal infections, such as the vaccines for influenza and human papilloma virus. We recently demonstrated the ability of vectored immunoprophylaxis (VIP) to prevent intravenous transmission of HIV in humanized mice using broadly neutralizing antibodies. Here we demonstrate that VIP is capable of protecting humanized mice from intravenous as well as vaginal challenge with diverse HIV strains despite repeated exposures. Moreover, animals receiving VIP that expresses a modified VRC07 antibody were completely resistant to repetitive intravaginal challenge by a heterosexually transmitted founder HIV strain, suggesting that VIP may be effective in preventing vaginal transmission of HIV between humans.
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http://dx.doi.org/10.1038/nm.3471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990417PMC
March 2014

Calcium phosphate-bearing matrices induce osteogenic differentiation of stem cells through adenosine signaling.

Proc Natl Acad Sci U S A 2014 Jan 6;111(3):990-5. Epub 2014 Jan 6.

Departments of Bioengineering, Chemistry and Biochemistry, and Nanoengineering, Institute of Engineering in Medicine, and Materials Science and Engineering, University of California, San Diego, La Jolla, CA 92093.

Synthetic matrices emulating the physicochemical properties of tissue-specific ECMs are being developed at a rapid pace to regulate stem cell fate. Biomaterials containing calcium phosphate (CaP) moieties have been shown to support osteogenic differentiation of stem and progenitor cells and bone tissue formation. By using a mineralized synthetic matrix mimicking a CaP-rich bone microenvironment, we examine a molecular mechanism through which CaP minerals induce osteogenesis of human mesenchymal stem cells with an emphasis on phosphate metabolism. Our studies show that extracellular phosphate uptake through solute carrier family 20 (phosphate transporter), member 1 (SLC20a1) supports osteogenic differentiation of human mesenchymal stem cells via adenosine, an ATP metabolite, which acts as an autocrine/paracrine signaling molecule through A2b adenosine receptor. Perturbation of SLC20a1 abrogates osteogenic differentiation by decreasing intramitochondrial phosphate and ATP synthesis. Collectively, this study offers the demonstration of a previously unknown mechanism for the beneficial role of CaP biomaterials in bone repair and the role of phosphate ions in bone physiology and regeneration. These findings also begin to shed light on the role of ATP metabolism in bone homeostasis, which may be exploited to treat bone metabolic diseases.
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http://dx.doi.org/10.1073/pnas.1321717111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903237PMC
January 2014

A 1-day imported fire ant rush immunotherapy schedule with and without premedication.

Ann Allergy Asthma Immunol 2013 Dec 18;111(6):562-6. Epub 2013 Sep 18.

San Antonio Military Medical Center, San Antonio, Texas. Electronic address:

Background: Rush immunotherapy (RIT) schedules can expedite protection in individuals sensitive to imported fire ant (IFA) stings.

Objective: To evaluate the safety and efficacy of 1-day RIT with IFA whole body extract (WBE) and determine the benefit of premedication with antihistamines and prednisone.

Methods: Patients with systemic reactions to IFAs and evidence of specific IgE by skin test or serologic test started a 1-day RIT protocol without premedication. The 1-day RIT protocol consisted of a total of 10 injections every 30 to 60 minutes to achieve a 0.3-mL 1:100 (wt/vol) dose. A higher systemic reaction rate (SRR) prompted protocol revision to include a 3-day course of oral 20 mg of prednisone twice daily, 150 mg of ranitidine, and 10 mg of loratadine started 2 days before the 1-day RIT. Patients returned on days 8 and 15 to receive a 0.5 mL 1:100 (wt/vol) maintenance injection. The effectiveness of the RIT was evaluated with a sting challenge on approximately day 22.

Results: Eighty of the 96 patients enrolled initiated the 1-day RIT. The first nonpremedicated group exhibited a SRR of 24.3% (9 of 37 patients), whereas the revised premedicated group had a SRR of 9.5% (4 of 42 patients; P = .07). The most severe reaction during RIT included dizziness, angioedema, and urticaria. Sting challenges on 53 patients resulted in 1 mild rhinitis reaction (efficacy, 98.1%).

Conclusion: One-day RIT with IFA WBE for IFA hypersensitivity is efficacious. Although there was a trend with premedications to reduce SRRs during the RIT, safety data with premedication require confirmation in a larger trial.
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http://dx.doi.org/10.1016/j.anai.2013.08.021DOI Listing
December 2013

The histamine H4 receptor mediates inflammation and Th17 responses in preclinical models of arthritis.

Ann Rheum Dis 2014 Mar 14;73(3):600-8. Epub 2013 Oct 14.

Department of Immunology, Janssen Research & Development, , San Diego, California, USA.

Objective: The histamine H4 receptor (H4R) has been shown to drive inflammatory responses in models of asthma, colitis and dermatitis, and in these models it appears to affect both innate and adaptive immune responses. In this study, we used both H4R-deficient mice and a specific H4R antagonist, JNJ 28307474, to investigate the involvement of the H4R in mouse arthritis models.

Methods: H4R-deficient mice and wild-type mice administered the H4R antagonist were studied in models of collagen antibody-induced arthritis (CAIA) and collagen-induced arthritis (CIA). The impact on Th17 cells was assessed by restimulation of inguinal lymphocytes in the disease or immunisation models and with in vitro stimulation of whole blood.

Results: Both H4R-deficient mice and mice treated with the H4R antagonist exhibited reduced arthritis disease severity in both CAIA and CIA models. This was evident from the reduction in disease score and in joint histology. In the CIA model, treatment with the H4R antagonist reduced the number of interleukin (IL)-17 positive cells in the lymph node and the total production of IL-17. Th17 cell development in vivo was reduced in H4R-deficient mice or in mice treated with an H4R antagonist. Finally, treatment of both mouse and human blood with an H4R antagonist reduced the production of IL-17 when cells were stimulated in vitro.

Conclusions: These results implicate the H4R in disease progression in arthritis and in the production of IL-17 from Th17 cells. This work supports future clinical exploration of H4R antagonists for the treatment of rheumatoid arthritis.
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http://dx.doi.org/10.1136/annrheumdis-2013-203832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4151522PMC
March 2014

Synthesis and extended activity of triazole-containing macrocyclic protease inhibitors.

Chemistry 2013 Jun 18;19(24):7975-81. Epub 2013 Apr 18.

School of Chemistry & Physics, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia.

Peptide-derived protease inhibitors are an important class of compounds with the potential to treat a wide range of diseases. Herein, we describe the synthesis of a series of triazole-containing macrocyclic protease inhibitors pre-organized into a β-strand conformation and an evaluation of their activity against a panel of proteases. Acyclic azido-alkyne-based aldehydes are also evaluated for comparison. The macrocyclic peptidomimetics showed considerable activity towards calpain II, cathepsin L and S, and the 20S proteasome chymotrypsin-like activity. Some of the first examples of highly potent macrocyclic inhibitors of cathepsin S were identified. These adopt a well-defined β-strand geometry as shown by NMR spectroscopy, X-ray analysis, and molecular docking studies.
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http://dx.doi.org/10.1002/chem.201204260DOI Listing
June 2013

Pyrazole-based arylalkyne cathepsin S inhibitors. Part III: modification of P4 region.

Bioorg Med Chem Lett 2013 Feb 21;23(4):1070-4. Epub 2012 Dec 21.

Janssen Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.

Novel classes of tetrahydropyrido-pyrazole thioether amines and arylalkynes that display potency against human Cathepsin S have been previously reported. Here, key pharmacophoric elements of these two classes are merged, and SAR investigations of the P4 region are described, in conjunction with re-optimization of the P5 and P1/P1'/P3 regions. Identification of meta-substituted arylalkynes with good potency and improved solubility is described.
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http://dx.doi.org/10.1016/j.bmcl.2012.12.014DOI Listing
February 2013

Independent analysis of the flagellum surface and matrix proteomes provides insight into flagellum signaling in mammalian-infectious Trypanosoma brucei.

Mol Cell Proteomics 2011 Oct 19;10(10):M111.010538. Epub 2011 Jun 19.

Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA.

The flagellum of African trypanosomes is an essential and multifunctional organelle that functions in motility, cell morphogenesis, and host-parasite interaction. Previous studies of the trypanosome flagellum have been limited by the inability to purify flagella without first removing the flagellar membrane. This limitation is particularly relevant in the context of studying flagellum signaling, as signaling requires surface-exposed proteins in the flagellar membrane and soluble signaling proteins in the flagellar matrix. Here we employ a combination of genetic and mechanical approaches to purify intact flagella from the African trypanosome, Trypanosoma brucei, in its mammalian-infectious stage. We combined flagellum purification with affinity-purification of surface-exposed proteins to conduct independent proteomic analyses of the flagellum surface and matrix fractions. The proteins identified encompass a broad range of molecular functionalities, including many predicted to function in signaling. Immunofluorescence and RNA interference studies demonstrate flagellum localization and function for proteins identified and provide insight into mechanisms of flagellum attachment and motility. The flagellum surface proteome includes many T. brucei-specific proteins and is enriched for proteins up-regulated in the mammalian-infectious stage of the parasite life-cycle. The combined results indicate that the flagellum surface presents a diverse and dynamic host-parasite interface that is well-suited for host-parasite signaling.
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http://dx.doi.org/10.1074/mcp.M111.010538DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3205874PMC
October 2011

Thioether acetamides as P3 binding elements for tetrahydropyrido-pyrazole cathepsin S inhibitors.

Bioorg Med Chem Lett 2010 Apr 8;20(7):2379-82. Epub 2010 Feb 8.

Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, United States.

A series of tetrahydropyrido-pyrazole cathepsin S (CatS) inhibitors with thioether acetamide functional groups were prepared with the goal of improving upon the cellular activity of amidoethylthioethers. This Letter describes altered amide connectivity, in conjunction with changes to other binding elements, resulting in improved potency, as well as increased knowledge of the relationship between this chemotype and human CatS activity.
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http://dx.doi.org/10.1016/j.bmcl.2010.01.103DOI Listing
April 2010

Discovery and SAR of novel pyrazole-based thioethers as cathepsin S inhibitors. Part 2: Modification of P3, P4, and P5 regions.

Bioorg Med Chem Lett 2010 Apr 1;20(7):2375-8. Epub 2010 Feb 1.

Johnson & Johnson Pharmaceutical Research & Development L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.

A novel class of tetrahydropyrido-pyrazole thioether amines that display potency against human Cathepsin S have been previously reported. Here, further SAR investigations of the P3, P4, and P5 regions are described. In particular, 4-fluoropiperidine is identified as a competent P3 binding element when utilized in conjunction with a (S)-2-hydroxypropyl linker-containing P5 moiety and oxamide or sulfonamide P4 substitution.
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http://dx.doi.org/10.1016/j.bmcl.2010.01.104DOI Listing
April 2010

Discovery and SAR of novel pyrazole-based thioethers as cathepsin S inhibitors: part 1.

Bioorg Med Chem Lett 2010 Apr 28;20(7):2370-4. Epub 2010 Jan 28.

Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.

A series of pyrazole-based thioethers were prepared and found to be potent cathepsin S inhibitors. A crystal structure of 13 suggests that the thioether moiety may bind to the S3 pocket of the enzyme. Additional optimization led to the discovery of aminoethylthioethers with improved enzymatic activity and submicromolar cellular potency.
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http://dx.doi.org/10.1016/j.bmcl.2010.01.108DOI Listing
April 2010