30 results on '"Huynh VT"'
Search Results
2. Effect of talc and vitamin E TPGS on manufacturability, stability and release properties of trilaurin-based formulations for hot-melt coating.
- Author
-
Huynh VT, de Paiva Lacerda S, Espitalier F, Beyssac E, and Ré MI
- Subjects
- Triglycerides, Solubility, Talc, Vitamin E chemistry
- Abstract
This study was focused on one particular case of hot-melt coating with trilaurin - a solid medium-chain monoacid triglyceride. The challenge of using trilaurin as coating agent in melting-based processes is linked to its relatively low melting profile: 15.6 °C (T
m,α ), 35.1 °C ( [Formula: see text] ) and 45.7 °C (Tm,β ). From a process perspective, the only possibility to generate products coated with formulations composed of trilaurin is by setting thermal operational conditions above Tm,α . From a material perspective, this processing possibility depends principally on trilaurin crystallisation which was investigated via a set of analytical techniques including turbidimetry, calorimetry, hot-melt goniometry, and polarised light microscopy. A highly soluble drug model substrate (sodium chloride crystals) was coated with three selected trilaurin-based formulations: (i) trilaurin, (ii) trilaurin plus talc, and (iii) trilaurin plus vitamin E TPGS and talc. Coated salt crystals were then analysed to investigate processing performance, coating quality, stability and release properties under digestion effect. The results show that firstly, talc addition promotes nucleation and crystal growth and, as a consequence, it facilitates the manufacture of trilaurin-based formulations. Secondly, the formulation of a solid triglyceride and a hydrophilic surfactant could potentially cause release instability, but formula (iii) was found to be stabilised by a mechanism whereby trilaurin crystallization enhanced in the presence of talc immobilised vitamin E TPGS in its crystal lattice. Thirdly, talc addition did not significantly influence trilaurin digestion which endows products with an immediate release in lipolytic conditions instead of an extended liberation in pure water. Nor did the addition of one or two additives alter the extent of trilaurin digestion under the conditions studied. These important findings relate to product manufacturability, stability, and release properties. A good understanding of material properties (e.g. crystallisation, polymorphism, digestibility) is essential for melt-processing, lipid coating stabilising and modulation of release profile of solid lipid-coated product, as demonstrated in this case study with trilaurin., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
3. Closed-loop control systems for pumps used in portable analytical systems.
- Author
-
Naz SA, Huynh VT, Doeven EH, Adams S, Kouzani A, and Guijt RM
- Subjects
- Reproducibility of Results, Syringes, Algorithms
- Abstract
The demand for accurate control of the flowrate/pressure in chemical analytical systems has given rise to the adoption of mechatronic approaches in analytical instruments. A mechatronic device is a synergistic system which combines mechanical, electronic, computer and control components. In the development of portable analytical devices, considering the instrument as a mechatronic system can be useful to mitigate compromises made to decrease space, weight, or power consumption. Fluid handling is important for reliability, however, commonly utilized platforms such as syringe and peristaltic pumps are typically characterized by flow/pressure fluctuations and slow responses. Closed loop control systems have been used effectively to decrease the difference between desired and realized fluidic output. This review discusses the way control systems have been implemented for enhanced fluidic control, categorized by pump type. Advanced control strategies used to enhance the transient and the steady state responses are discussed, along with examples of their implementation in portable analytical systems. The review is concluded with the outlook that the challenge in adequately expressing the complexity and dynamics of the fluidic network as a mathematical model has yielded a trend towards the adoption of experimentally informed models and machine learning approaches., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)
- Published
- 2023
- Full Text
- View/download PDF
4. Nelarabine, etoposide, and cyclophosphamide in relapsed pediatric T-acute lymphoblastic leukemia and T-lymphoblastic lymphoma (study T2008-002 NECTAR).
- Author
-
Whitlock JA, Malvar J, Dalla-Pozza L, Goldberg JM, Silverman LB, Ziegler DS, Attarbaschi A, Brown PA, Gardner RA, Gaynon PS, Hutchinson R, Huynh VT, Jeha S, Marcus L, Messinger Y, Schultz KR, Cassar J, Locatelli F, Zwaan CM, Wood BL, Sposto R, and Gore L
- Subjects
- Antineoplastic Combined Chemotherapy Protocols adverse effects, Arabinonucleosides adverse effects, Child, Cyclophosphamide adverse effects, Etoposide adverse effects, Humans, Nucleosides therapeutic use, Plant Nectar, Recurrence, Lymphoma, Non-Hodgkin drug therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma drug therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma etiology, Precursor T-Cell Lymphoblastic Leukemia-Lymphoma pathology
- Abstract
Children with relapse of T-cell acute lymphoblastic leukemia (T-ALL) or lymphoblastic lymphoma (T-LBL) have a dismal prognosis, largely due to difficulty attaining second remission. We hypothesized that adding etoposide and cyclophosphamide to the nucleoside analog nelarabine could improve response rates over single-agent nelarabine for relapsed T-ALL and T-LBL. This phase I dose-escalation trial's primary objective was to evaluate the dose and safety of nelarabine given in combination with etoposide at 100 mg/m
2 /day and cyclophosphamide at 330-400 mg/m2 /day, each for 5 consecutive days in children with either T-ALL (13 patients) or T-LBL (10 patients). Twenty-three patients were treated at three dose levels; 21 were evaluable for dose-limiting toxicities (DLT) and response. The recommended phase II doses (RP2D) for this regimen, when given daily ×5 every 3 weeks, were nelarabine 650 mg/m2 /day, etoposide 100 mg/m2 /day, and cyclophosphamide 400 mg/m2 /day. DLTs included peripheral motor and sensory neuropathies. An expansion cohort to evaluate responses at the RP2D was terminated early due to slow accrual. The overall best response rate was 38% (8/21), with 33% (4/12) responses in the T-ALL cohort and 44% (4/9) responses in the T-LBL cohort. These response rates are comparable to those seen with single-agent nelarabine in this setting. These data suggest that the addition of cyclophosphamide and etoposide to nelarabine does not increase the incidence of neurologic toxicities or the response rate beyond that obtained with single-agent nelarabine in children with first relapse of T-ALL and T-LBL., (© 2022 Wiley Periodicals LLC.)- Published
- 2022
- Full Text
- View/download PDF
5. Decitabine and vorinostat with FLAG chemotherapy in pediatric relapsed/refractory AML: Report from the therapeutic advances in childhood leukemia and lymphoma (TACL) consortium.
- Author
-
Pommert L, Schafer ES, Malvar J, Gossai N, Florendo E, Pulakanti K, Heimbruch K, Stelloh C, Chi YY, Sposto R, Rao S, Huynh VT, Brown P, Chang BH, Colace SI, Hermiston ML, Heym K, Hutchinson RJ, Kaplan JA, Mody R, O'Brien TA, Place AE, Shaw PH, Ziegler DS, Wayne A, Bhojwani D, and Burke MJ
- Subjects
- Antineoplastic Combined Chemotherapy Protocols adverse effects, Child, Cytarabine, Decitabine therapeutic use, Humans, Vorinostat, Leukemia, Myeloid, Acute drug therapy, Leukemia, Myeloid, Acute genetics, Leukemia, Myeloid, Acute pathology, Lymphoma drug therapy
- Abstract
Survival outcomes for relapsed/refractory pediatric acute myeloid leukemia (R/R AML) remain dismal. Epigenetic changes can result in gene expression alterations which are thought to contribute to both leukemogenesis and chemotherapy resistance. We report results from a phase I trial with a dose expansion cohort investigating decitabine and vorinostat in combination with fludarabine, cytarabine, and G-CSF (FLAG) in pediatric patients with R/R AML [NCT02412475]. Thirty-seven patients enrolled with a median age at enrollment of 8.4 (range, 1-20) years. There were no dose limiting toxicities among the enrolled patients, including two patients with Down syndrome. The recommended phase 2 dose of decitabine in combination with vorinostat and FLAG was 10 mg/m
2 . The expanded cohort design allowed for an efficacy evaluation and the overall response rate among 35 evaluable patients was 54% (16 complete response (CR) and 3 complete response with incomplete hematologic recovery (CRi)). Ninety percent of responders achieved minimal residual disease (MRD) negativity (<0.1%) by centralized flow cytometry and 84% (n = 16) successfully proceeded to hematopoietic stem cell transplant. Two-year overall survival was 75.6% [95%CI: 47.3%, 90.1%] for MRD-negative patients vs. 17.9% [95%CI: 4.4%, 38.8%] for those with residual disease (p < .001). Twelve subjects (34%) had known epigenetic alterations with 8 (67%) achieving a CR, 7 (88%) of whom were MRD negative. Correlative pharmacodynamics demonstrated the biologic activity of decitabine and vorinostat and identified specific gene enrichment signatures in nonresponding patients. Overall, this therapy was well-tolerated, biologically active, and effective in pediatric patients with R/R AML, particularly those with epigenetic alterations., (© 2022 Wiley Periodicals LLC.)- Published
- 2022
- Full Text
- View/download PDF
6. Bioactive Glass Fiber-Reinforced Plastic Composites Prompt a Crystallographic Lophelia Atoll-Like Skeletal Microarchitecture Actuating Periosteal Cambium.
- Author
-
Rethi L, Lu L, Huynh VT, Manga YB, Rethi L, Mutalik C, Chen CH, and Chuang EY
- Subjects
- Bone Regeneration drug effects, Crystallography, X-Ray, Materials Testing, Osseointegration drug effects, Periosteum physiology, Prostheses and Implants, Bone Substitutes chemistry, Bone Substitutes pharmacology, Glass chemistry, Periosteum drug effects, Plastics chemistry
- Abstract
The touchstone for bone replacing or anchoring trauma implants, besides resorption, includes functional ankylosis at a fixation point and replacement by viable functional neo-bone tissues. These parameters redefined the concept of "resorbability" as "bioresorbability." Interference screws are the most commonly used resorbable anchoring implants for anterior cruciate ligament (ACL) reconstruction (surgery). Over the years, the bioresorbable screw fixation armamentarium has amplified countless choices, but instability and postimplantation complications have raised concerns about its reliability and efficacy. Owing to this interest, in this work, bioactive glass fiber-reinforced plastic (BGFP) composites with (BGFP nb 5) and without (BGFP5) niobicoxide composing multiplexed network modifiers are reported as bioresorbable bone-anchoring substitutes. These synergistically designed composites have a fabricated structure of continuous, unidirectional BG fibers reinforced in an epoxy resin matrix using "melt-drawing and microfabrication" technology. The BGFP microarchitecture is comprised of multiplexed oxide components that influence bioactive response in a distinctive lophelia atoll-like apatite formation. Furthermore, it assists in the proliferation, adherence, and migration of bone marrow-derived mesenchymal stem cells. It also exhibits superior physicochemical characteristics such as surface roughness, hydrophilic exposure, distinctive flexural strength, and bioresorption. Thus, it induces restorative bone osseointegration and osteoconduction and actuates periosteum function. In addition, the BGFP influences the reduction of DH5-α Escherichia coli in suspension culture, demonstrating potential antibacterial efficacy. In conclusion, the BGFP composite therapeutic efficacy demonstrates distinctive material characteristics aiding in bone regeneration and restoration that could serve as a pioneer in orthopedic regenerative medicine.
- Published
- 2021
- Full Text
- View/download PDF
7. Coding and non-coding roles of MOCCI (C15ORF48) coordinate to regulate host inflammation and immunity.
- Author
-
Lee CQE, Kerouanton B, Chothani S, Zhang S, Chen Y, Mantri CK, Hock DH, Lim R, Nadkarni R, Huynh VT, Lim D, Chew WL, Zhong FL, Stroud DA, Schafer S, Tergaonkar V, St John AL, Rackham OJL, and Ho L
- Subjects
- Cell Line, Electron Transport Complex IV metabolism, Gene Knockout Techniques, Humans, Inflammation genetics, Inflammation pathology, Membrane Potential, Mitochondrial immunology, MicroRNAs genetics, Mitochondria immunology, Mitochondria pathology, Primary Cell Culture, Reactive Oxygen Species metabolism, Up-Regulation immunology, Electron Transport Complex IV genetics, Genetic Pleiotropy immunology, Inflammation immunology, MicroRNAs metabolism, Neoplasm Proteins genetics, Neoplasm Proteins metabolism, Nuclear Proteins genetics, Nuclear Proteins metabolism
- Abstract
Mito-SEPs are small open reading frame-encoded peptides that localize to the mitochondria to regulate metabolism. Motivated by an intriguing negative association between mito-SEPs and inflammation, here we screen for mito-SEPs that modify inflammatory outcomes and report a mito-SEP named "Modulator of cytochrome C oxidase during Inflammation" (MOCCI) that is upregulated during inflammation and infection to promote host-protective resolution. MOCCI, a paralog of the NDUFA4 subunit of cytochrome C oxidase (Complex IV), replaces NDUFA4 in Complex IV during inflammation to lower mitochondrial membrane potential and reduce ROS production, leading to cyto-protection and dampened immune response. The MOCCI transcript also generates miR-147b, which targets the NDUFA4 mRNA with similar immune dampening effects as MOCCI, but simultaneously enhances RIG-I/MDA-5-mediated viral immunity. Our work uncovers a dual-component pleiotropic regulation of host inflammation and immunity by MOCCI (C15ORF48) for safeguarding the host during infection and inflammation.
- Published
- 2021
- Full Text
- View/download PDF
8. GREB1: An evolutionarily conserved protein with a glycosyltransferase domain links ERα glycosylation and stability to cancer.
- Author
-
Shin EM, Huynh VT, Neja SA, Liu CY, Raju A, Tan K, Tan NS, Gunaratne J, Bi X, Iyer LM, Aravind L, and Tergaonkar V
- Subjects
- Animals, Carrier Proteins genetics, Female, Gene Expression Regulation, Neoplastic, Glycosylation, Glycosyltransferases genetics, Humans, Mammals metabolism, Mice, Neoplasm Proteins metabolism, Breast Neoplasms genetics, Breast Neoplasms metabolism, Estrogen Receptor alpha genetics, Estrogen Receptor alpha metabolism, Membrane Proteins metabolism
- Abstract
What covalent modifications control the temporal ubiquitination of ERα and hence the duration of its transcriptional activity remain poorly understood. We show that GREB1, an ERα-inducible enzyme, catalyzes O-GlcNAcylation of ERα at residues T553/S554, which stabilizes ERα protein by inhibiting association with the ubiquitin ligase ZNF598. Loss of GREB1-mediated glycosylation of ERα results in reduced cellular ERα levels and insensitivity to estrogen. Higher GREB1 expression in ERα
+ve breast cancer is associated with greater survival in response to tamoxifen, an ERα agonist. Mice lacking Greb1 exhibit growth and fertility defects reminiscent of phenotypes in ERα-null mice. In summary, this study identifies GREB1, a protein with an evolutionarily conserved domain related to DNA-modifying glycosyltransferases of bacteriophages and kinetoplastids, as the first inducible and the only other (apart from OGT) O-GlcNAc glycosyltransferase in mammalian cytoplasm and ERα as its first substrate., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)- Published
- 2021
- Full Text
- View/download PDF
9. Synthesis of tertiary amines by direct Brønsted acid catalyzed reductive amination.
- Author
-
Hussein MA, Dinh AH, Huynh VT, and Nguyen TV
- Abstract
Tertiary amines are ubiquitous and valuable compounds in synthetic chemistry, with a wide range of applications in organocatalysis, organometallic complexes, biological processes and pharmaceutical chemistry. One of the most frequently used pathways to synthesize tertiary amines is the reductive amination reaction of carbonyl compounds. Despite developments of numerous new reductive amination methods in the past few decades, this reaction generally requires non-atom-economic processes with harsh conditions and toxic transition-metal catalysts. Herein, we report simple yet practical protocols using triflic acid as a catalyst to efficiently promote the direct reductive amination reactions of carbonyl compounds on a broad range of substrates. Applications of this new method to generate valuable heterocyclic frameworks and polyamines are also included.
- Published
- 2020
- Full Text
- View/download PDF
10. Clinical spectrum, prognosis and estimated prevalence of DNAJB11-kidney disease.
- Author
-
Huynh VT, Audrézet MP, Sayer JA, Ong AC, Lefevre S, Le Brun V, Després A, Senum SR, Chebib FT, Barroso-Gil M, Patel C, Mallett AJ, Goel H, Mallawaarachchi AC, Van Eerde AM, Ponlot E, Kribs M, Le Meur Y, Harris PC, and Cornec-Le Gall E
- Subjects
- Aged, England, Female, HSP40 Heat-Shock Proteins, Humans, Male, Middle Aged, Mutation, Prevalence, Prognosis, Polycystic Kidney, Autosomal Dominant diagnosis, Polycystic Kidney, Autosomal Dominant epidemiology, Polycystic Kidney, Autosomal Dominant genetics, TRPP Cation Channels genetics
- Abstract
Monoallelic mutations of DNAJB11 were recently described in seven pedigrees with atypical clinical presentations of autosomal dominant polycystic kidney disease. DNAJB11 encodes one of the main cofactors of the endoplasmic reticulum chaperon BiP, a heat-shock protein required for efficient protein folding and trafficking. Here we conducted an international collaborative study to better characterize the DNAJB11-associated phenotype. Thirteen different loss-of-function variants were identified in 20 new pedigrees (54 affected individuals) by targeted next-generation sequencing, whole-exome sequencing or whole-genome sequencing. Amongst the 77 patients (27 pedigrees) now in total reported, 32 reached end stage kidney disease (range, 55-89 years, median age 75); without a significant difference between males and females. While a majority of patients presented with non-enlarged polycystic kidneys, renal cysts were inconsistently identified in patients under age 45. Vascular phenotypes, including intracranial aneurysms, dilatation of the thoracic aorta and dissection of a carotid artery were present in four pedigrees. We accessed Genomics England 100,000 genomes project data, and identified pathogenic variants of DNAJB11 in nine of 3934 probands with various kidney and urinary tract disorders. The clinical diagnosis was cystic kidney disease for eight probands and nephrocalcinosis for one proband. No additional pathogenic variants likely explaining the kidney disease were identified. Using the publicly available GnomAD database, DNAJB11 genetic prevalence was calculated at 0.85/10.000 individuals. Thus, establishing a precise diagnosis in atypical cystic or interstitial kidney disease is crucial, with important implications in terms of follow-up, genetic counseling, prognostic evaluation, therapeutic management, and for selection of living kidney donors., (Copyright © 2020 International Society of Nephrology. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
11. Halide Anion Triggered Reactions of Michael Acceptors with Tropylium Ion.
- Author
-
Hussein MA, Tran UPN, Huynh VT, Ho J, Bhadbhade M, Mayr H, and Nguyen TV
- Abstract
Tropylium bromide undergoes noncatalyzed, regioselective additions to a large variety of Michael acceptors. In this way, acrylic esters are converted into β-bromo-α-cycloheptatrienylpropionic esters. The reactions are interpreted as nucleophilic attack of bromide ions at the electron-deficient olefins and the approach of the tropylium ion to the incipient carbanion. Quantum chemical calculations were performed to elucidate the analogy to the amine- or phosphine-catalyzed Rauhut-Currier reactions. Subsequent synthetic transformations of the bromo-cycloheptatrienylated adducts are reported., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2020
- Full Text
- View/download PDF
12. Evaluation of cropping method for perennial ratoon rice: Adaptation of SALIBU to triple-cropping in Vietnam.
- Author
-
Oda M, Nguyen HC, and Huynh VT
- Subjects
- Crops, Agricultural growth & development, Indonesia, Vietnam, Agriculture methods, Oryza growth & development
- Abstract
Background : Generally, the yield of ratoon rice is at most 50% of the main crop. However, a cropping method "SALIBU" achieved more yield than the main crop and enables the perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method in Indonesia, the effect of each management practice is unclear. Methodology : We evaluated the effect size using an L
16 orthogonal array design pot experiment in triple-cropping rice in Vietnam. The robustness was checked by duplicating the experiment under standard and poor conditions. Results and Discussion : Positive large effects were shown in the poor conditions only. Cutting twice most affected the number of ratoon tillers. Importantly, the effect was positive under poor conditions but negative under standard conditions. Late irrigation had a robust negative effect. No treatment is effective in the triple-cropping of standard conditions. The SALIBU includes practices with unstable, negative, or minimal effects. The unstable effects show the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions : No additional practice is effective for changing the triple-cropping to perennial ratoon cropping except harvesting near the ground. However, further work will be conducted to clarify the interaction between cutting twice and the cultivation condition., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Oda M et al.)- Published
- 2019
- Full Text
- View/download PDF
13. Evaluation of cropping method for perennial ratoon rice (SALIBU).
- Author
-
Oda M, Nguyen HC, and Huynh VT
- Subjects
- Crops, Agricultural growth & development, Indonesia, Vietnam, Agriculture methods, Oryza growth & development
- Abstract
Background : Generally, the yield of ratoon rice is at most 50% of the main crop. However, a cropping method "SALIBU" achieved more yield than the main crop and could be used for the cultivation of perennial cropping. Although the SALIBU method is implementing 10 additional management practices to conventional method, the effect of each management practice is unclear. Therefore, we aimed to evaluate the effect size and the robustness of each management practice. Methodology : We evaluated the effect size using an L
16 orthogonal array design pot experiment. For the robustness, we duplicated the experiment under both standard and checked whether the practice shows the same effect size. The bad conditions were low plant density, no fertilization, continuous flooding water management, and late harvesting. Results : The ratoon rice yield was proportional to the number of ratoon tillers used as in conventionally produced ratoon rice. Late cutting was most affected to the number of ratoon tillers. Importantly, this effect was reversed; the effect was positive under bad conditions, but was negative under standard conditions. Furthermore, late irrigation, a recommended management practice, had a robust negative effect on ratoon tillers and yield under both the conditions. Positive large effects were shown in the bad condition only. Discussion : Our results show that the SALIBU cropping method includes practices with unstable, negative, or minimal effects. The practices have unstable effects should be clarifying the interaction with the condition. The practices that have negative effects should exclude. Using practice on small effect size should depend on a cost-benefit analysis. Conclusions : SALIBU will be acceptable to the Mekong Delta triple cropping rice cultivation without the additional practice of original SALIBU cropping method. However, further work is needed to clarify the interaction between late cutting and the cultivation condition, and on the negative effect of late irrigation., Competing Interests: No competing interests were disclosed., (Copyright: © 2019 Oda M et al.)- Published
- 2019
- Full Text
- View/download PDF
14. An efficient method for retro-Claisen-type C-C bond cleavage of diketones with tropylium catalyst.
- Author
-
Hussein MA, Huynh VT, Hommelsheim R, Koenigs RM, and Nguyen TV
- Abstract
The retro-Claisen reaction is frequently used in organic synthesis to access ester derivatives from 1,3-dicarbonyl precursors. The C-C bond cleavage in this reaction is usually promoted by a number of transition-metal Lewis acid catalysts or organic Brønsted acids/bases. Herein we report a new convenient and efficient method utilizing the tropylium ion as a mild and environmentally friendly organocatalyst to mediate retro-Claisen-type reactions. Using this method, a range of synthetically valuable substances can be accessed via solvolysis of 1,3-dicarbonyl compounds.
- Published
- 2018
- Full Text
- View/download PDF
15. Aqueous Polymeric Hollow Particles as an Opacifier by Emulsion Polymerization Using Macro-RAFT Amphiphiles.
- Author
-
Pham BTT, Nguyen D, Huynh VT, Pan EH, Shirodkar-Robinson B, Carey M, Serelis AK, Warr GG, Davey T, Such CH, and Hawkett BS
- Abstract
A robust polymerization technique that enables the surfactant-free aqueous synthesis of a high solid content latex containing polymeric hollow particles is presented. Uniquely designed amphiphilic macro-reversible addition fragmentation chain transfer (RAFT) copolymers were used as sole stabilizers for monomer emulsification as well as for free-radical emulsion polymerization. The polymerization was found to be under RAFT control, generating various morphologies from spherical particles, wormlike structures to polymer vesicles. The final particles were dominantly polymeric vesicles which had a substantially uniform and continuous polymer layer around a single aqueous filled void. They produced hollow particles once dried and were successfully used as opacifiers to impart opacity into polymer paint films. This method is simple, can be performed in a controllable and reproducible manner, and may be performed using diverse procedures.
- Published
- 2018
- Full Text
- View/download PDF
16. Hepatitis C Virus Nonstructural 5A Protein Interacts with Abelson Interactor 1 and Modulates Epidermal Growth Factor-mediated MEK/ERK Signaling Pathway.
- Author
-
Huynh VT, Lim YS, Tran SC, Pham TM, Nguyen LN, and Hwang SB
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Cell Line, Cytoskeletal Proteins genetics, Early Growth Response Protein 1 genetics, Early Growth Response Protein 1 metabolism, Epidermal Growth Factor genetics, Gene Silencing, Humans, Protein Binding, Viral Nonstructural Proteins genetics, Adaptor Proteins, Signal Transducing metabolism, Cytoskeletal Proteins metabolism, Epidermal Growth Factor metabolism, Hepacivirus physiology, MAP Kinase Signaling System, Viral Nonstructural Proteins metabolism, Virus Replication physiology
- Abstract
The propagation of hepatitis C virus (HCV) is highly dependent on host cellular factors. To identify the cellular factors involved in HCV propagation, we have previously performed protein microarray assays using the HCV nonstructural 5A (NS5A) protein as a probe. Of ∼9,000 host proteins immobilized in a microarray, ∼90 cellular proteins were identified as HCV NS5A interacting partners. Of these candidates, we selected Abelson interactor 1 (Abi1) for further characterization. Binding of HCV NS5A to Abi1 was verified by both in vitro pulldown and coimmunoprecipitation assays. HCV NS5A interacted with Abi1 through regions I + II of Abi1 and domain I of NS5A. We further demonstrated that Abi1 colocalized with the HCV NS5A protein in the cytoplasm. We showed that NS5A inhibited epidermal growth factor-mediated ERK and Egr1 activations and this inhibitory activity of NS5A was nullified in Abi1-knockdown cells. Moreover, silencing of Abi1 expression impaired HCV replication, whereas overexpression of Abi1 promoted HCV propagation. Collectively, these data indicate that HCV exploits host Abi1 protein via NS5A to modulate MEK/ERK signaling pathway for its own propagation., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2016
- Full Text
- View/download PDF
17. A targeted immunomic approach identifies diagnostic antigens in the human pathogen Babesia microti.
- Author
-
Cornillot E, Dassouli A, Pachikara N, Lawres L, Renard I, Francois C, Randazzo S, Brès V, Garg A, Brancato J, Pazzi JE, Pablo J, Hung C, Teng A, Shandling AD, Huynh VT, Krause PJ, Lepore T, Delbecq S, Hermanson G, Liang X, Williams S, Molina DM, and Ben Mamoun C
- Subjects
- Animals, Genome, Protozoan genetics, Humans, Kinetics, Mice, Protein Array Analysis, Antigens, Protozoan immunology, Babesia microti immunology, Babesiosis immunology, Biomarkers analysis
- Abstract
Background: Babesia microti is a protozoan parasite responsible for the majority of reported cases of human babesiosis and a major risk to the blood supply. Laboratory screening of blood donors may help prevent transfusion-transmitted babesiosis but there is no Food and Drug Administration-approved screening method yet available. Development of a sensitive, specific, and highly automated B. microti antibody assay for diagnosis of acute babesiosis and blood screening could have an important impact on decreasing the health burden of B. microti infection., Study Design and Methods: Herein, we take advantage of recent advances in B. microti genomic analyses, field surveys of the reservoir host, and human studies in endemic areas to apply a targeted immunomic approach to the discovery of B. microti antigens that serve as signatures of active or past babesiosis infections. Of 19 glycosylphosphatidylinositol (GPI)-anchored protein candidates (BmGPI1-19) identified in the B. microti proteome, 17 were successfully expressed, printed on a microarray chip, and used to screen sera from uninfected and B. microti-infected mice and humans to determine immune responses that are associated with active and past infection., Results: Antibody responses to various B. microti BmGPI antigens were detected and BmGPI12 was identified as the best biomarker of infection that provided high sensitivity and specificity when used in a microarray antibody assay., Conclusion: BmGPI12 alone or in combination with other BmGPI proteins is a promising candidate biomarker for detection of B. microti antibodies that might be useful in blood screening to prevent transfusion-transmitted babesiosis., (© 2016 AABB.)
- Published
- 2016
- Full Text
- View/download PDF
18. Nanodiamonds with Surface Grafted Polymer Chains as Vehicles for Cell Imaging and Cisplatin Delivery: Enhancement of Cell Toxicity by POEGMEMA Coating.
- Author
-
Huynh VT, Pearson S, Noy JM, Abboud A, Utama RH, Lu H, and Stenzel MH
- Abstract
Nanodiamonds (NDs) are highly promising drug carriers due to their biocompatibility, manipulable surface chemistry, and nonbleaching flourescence. In this communication, we compare the cytotoxicity of three ND-cisplatin systems in which cisplatin was incorporated via direct attachment to the ND surface, physical adsorption within a poly(oligo(ethylene glycol) methyl ether methacrylate) POEGMEMA surface coating, or complexation to 1,1-di- tert -butyl 3-(2-methacryloyloxy)ethyl)butane-1,1,3-tricarboxylate (MAETC) groups of a POEGMEMA- st -PMAETC surface layer. The polymer layers were introduced by grafting from RAFT-functionalized ND particles. All three ND systems displayed lower IC
50 values than free cisplatin in A2870 and A2870cis ovarian cancer cells. The two polymer-containing systems outperformed their "naked" counterpart, with the POEGMEMA-coated particles the most cytotoxic, displaying an IC50 of 1.5 μM, more than an order of magnitude lower than that of cisplatin. The enhanced cytotoxicity is attributed to promotion of cellular uptake by the hydrophilic surface polymer.- Published
- 2013
- Full Text
- View/download PDF
19. Proteome-scale antibody responses and outcome of Mycobacterium tuberculosis infection in nonhuman primates and in tuberculosis patients.
- Author
-
Kunnath-Velayudhan S, Davidow AL, Wang HY, Molina DM, Huynh VT, Salamon H, Pine R, Michel G, Perkins MD, Xiaowu L, Felgner PL, Flynn JL, Catanzaro A, and Gennaro ML
- Subjects
- Adult, Animals, Antibodies, Bacterial blood, Biomarkers blood, Humans, Macaca fascicularis, Middle Aged, Protein Array Analysis, Proteomics methods, Regression Analysis, Retrospective Studies, Antibodies, Bacterial biosynthesis, Monkey Diseases immunology, Monkey Diseases microbiology, Mycobacterium tuberculosis immunology, Proteome immunology, Tuberculosis immunology, Tuberculosis microbiology
- Abstract
Background: Biomarkers of progression from latent Mycobacterium tuberculosis infection to active tuberculosis are needed. We assessed correlations between infection outcome and antibody responses in macaques and humans by high-throughput, proteome-scale serological studies., Methods: Mycobacterium tuberculosis proteome microarrays were probed with serial sera from macaques representing various infection outcomes and with single-point human sera from tuberculosis suspects. Fluorescence intensity data were analyzed by calculating Z scores and associated P values. Temporal changes in macaque antibody responses were analyzed by polynomial regression. Correlations between human responses and sputum bacillary burden were assessed by quantile and hurdle regression., Results: Macaque outcome groups exhibited distinct antibody profiles: early, transient responses in latent infection and stable antibody increase in active and reactivation disease. In humans, antibody levels and reactive protein numbers increased with bacillary burden. Responses to a subset of 10 proteins were more tightly associated with disease state than reactivity to the broader reactive proteome., Conclusions: Integration of macaque and human data reveals dynamic properties of antibody responses in relation to outcome and leads to actionable findings for translational research. These include the potential of antibody responses to detect acute infection and preclinical tuberculosis and to identify serodiagnostic proteins for the spectrum of bacillary burden in tuberculosis.
- Published
- 2012
- Full Text
- View/download PDF
20. Block copolymer micelles with pendant bifunctional chelator for platinum drugs: effect of spacer length on the viability of tumor cells.
- Author
-
Huynh VT, Quek JY, de Souza PL, and Stenzel MH
- Subjects
- Antineoplastic Agents chemical synthesis, Antineoplastic Agents chemistry, Cell Survival drug effects, Chelating Agents chemical synthesis, Chelating Agents chemistry, Dose-Response Relationship, Drug, Drug Screening Assays, Antitumor, Humans, Methacrylates chemical synthesis, Methacrylates chemistry, Micelles, Models, Molecular, Molecular Structure, Organoplatinum Compounds chemical synthesis, Organoplatinum Compounds chemistry, Particle Size, Polyethylene Glycols chemical synthesis, Polyethylene Glycols chemistry, Structure-Activity Relationship, Surface Properties, Tumor Cells, Cultured, Antineoplastic Agents pharmacology, Chelating Agents pharmacology, Organoplatinum Compounds pharmacology
- Abstract
Three monomers with 1,3-dicarboxylate functional groups but varying spacer lengths were synthesized via carbon Michael addition using malonate esters and ethylene- (MAETC), butylene- (MABTC), and hexylene (MAHTC) glycol dimethacrylate, respectively. Poly[oligo-(ethylene glycol) methylether methacrylate] (POEGMEMA) was prepared in the presence of a RAFT (reversible addition-fragmentation chain transfer) agent, followed by chain extension with the prepared monomers to generate three different block copolymers (BP-E80, BP-B82, and BP-H79) with similar numbers of repeating units, but various spacer lengths as distinguishing features. Conjugation with platinum drugs created macromolecular platinum drugs resembling carboplatin. The amphiphilic natures of these Pt-containing block copolymers led to the formation micelles in solution. The rate of drug release of all micelles was similar, but a noticeable difference was the increasing stability of the micelle against dissociation with increasing spacer length. The platinum conjugated polymer showed high activity against A549, OVCAR3, and SKOV3 cancer cell lines exceeding the activity of carboplatin, but only the micelle based on the longest spacer had IC(50) values as low as cisplatin. Cellular uptake studies identified a better micelle uptake with increasing micelle stability as a possible reason for lower IC(50) values. The clonogenic assay revealed that micelles loaded with platinum drugs, in contrast to low molecular weight carboplatin, have not only better activity within the frame of a 72 h cell viability study, but also display a longer lasting effect by preventing the colony formation A549 for more than 10 days.
- Published
- 2012
- Full Text
- View/download PDF
21. Thiol-yne and thiol-ene "click" chemistry as a tool for a variety of platinum drug delivery carriers, from statistical copolymers to crosslinked micelles.
- Author
-
Huynh VT, Chen G, de Souza P, and Stenzel MH
- Subjects
- Chromatography, High Pressure Liquid, Magnetic Resonance Spectroscopy, Platinum chemistry, Spectrophotometry, Ultraviolet, Drug Carriers, Micelles, Platinum administration & dosage, Polymers chemistry, Sulfhydryl Compounds chemistry
- Abstract
Statistical and block copolymers based on poly(2-hydroxyethyl methacrylate) (PHEMA) and poly[oligo(ethylene glycol) methylether methacrylate] (POEGMEMA) were modified with 4-pentenoic anhydride or 4-oxo-4-(prop-2-ynyloxy)butanoic anhydride to generate polymers with pendant vinyl or acetylene, respectively. Subsequent thiol-ene or thiol-yne reaction with thioglycolic acid or 2-mercaptosuccinic acid leads to polymers with carboxylate functionalities, which were conjugated with cisplatin (cis-diamminedichloroplatinum(II) (CDDP)) to generate a drug carrier for Pt-drugs. Only the polymers modified with 2-mercaptosuccinic acid resulted in the formation of soluble well-defined polymers with gel formation being prevented. Due to the hydrophobicity of the drug, the block copolymers took on amphiphilic character leading to micelle formation. The micelles were in addition crosslinked to further stabilize their structure. Pt-containing statistical copolymer, micelles, and crosslinked micelles were then tested regarding their cellular uptake by the A549 lung cancer cell line to show a superior uptake of crosslinked micelles. However, due to the better Pt release of the statistical copolymer, the highest cytotoxicity was observed with this type of polymer architecture.
- Published
- 2011
- Full Text
- View/download PDF
22. Core-cross-linked micelles synthesized by clicking bifunctional Pt(IV) anticancer drugs to isocyanates.
- Author
-
Duong HT, Huynh VT, de Souza P, and Stenzel MH
- Subjects
- Antineoplastic Agents pharmacology, Chromatography, Gel, Drug Carriers, Drug Delivery Systems, Humans, Magnetic Resonance Spectroscopy, Mass Spectrometry, Organoplatinum Compounds pharmacology, Polyethylene Glycols chemistry, Polymers chemistry, Polymers pharmacology, Spectroscopy, Fourier Transform Infrared, Tumor Cells, Cultured, Antineoplastic Agents chemistry, Isocyanates chemistry, Lung Neoplasms drug therapy, Micelles, Organoplatinum Compounds chemistry, Polymers chemical synthesis
- Abstract
Most low molecular weight platinum-based anticancer drugs have a short circulation time in the bloodstream. One of the potential strategies to improve the targeted delivery of cisplatin and prolong its circulation is via the use of nanocarriers. An improved drug delivery system was developed via reversible addition-fragmentation chain transfer (RAFT) polymerization. In a one-pot reaction, the incorporation of anticancer drug and core cross-linking was simultaneously carried out by using the highly effective reaction of isocyanate groups in the core of the polymeric micelles poly(oligo(ethylene glycol) methyl ether methacrylate)-block-poly(styrene-co-3-isopropenyl-α,α-dimethylbenzyl isocyanate) (POEGMA-block-P(STY-co-TMI)) with amine groups in the prepared platinum(IV) drug. The micelles with platinum(IV) incorporated with a size of 36 nm were very stable in water. In a reductive environment, in this study simulated using ascorbate, the drug was released at a slow rate of 82% in 22 days and at the same time the cross-linked micelle broke down into free block copolymers as evidenced using inductively coupled plasma-mass spectrometer (ICP-MS), size exclusion chromatography (SEC), and dynamic light scattering (DLS). The in vitro study also revealed the promising antitumor activity of prepared platinum(IV) drugs encapsulated into the micelle structure.
- Published
- 2010
- Full Text
- View/download PDF
23. Dynamic antibody responses to the Mycobacterium tuberculosis proteome.
- Author
-
Kunnath-Velayudhan S, Salamon H, Wang HY, Davidow AL, Molina DM, Huynh VT, Cirillo DM, Michel G, Talbot EA, Perkins MD, Felgner PL, Liang X, and Gennaro ML
- Subjects
- Antibodies, Bacterial blood, Antibody Formation immunology, Antigens, Bacterial blood, Antigens, Bacterial immunology, Bacterial Proteins analysis, Host-Pathogen Interactions immunology, Humans, Mycobacterium tuberculosis metabolism, Mycobacterium tuberculosis physiology, Proteome analysis, Proteomics, Tuberculosis blood, Tuberculosis microbiology, Antibodies, Bacterial immunology, Bacterial Proteins immunology, Mycobacterium tuberculosis immunology, Proteome immunology, Tuberculosis immunology
- Abstract
Considerable effort has been directed toward controlling tuberculosis, which kills almost two million people yearly. High on the research agenda is the discovery of biomarkers of active tuberculosis (TB) for diagnosis and for monitoring treatment outcome. Rational biomarker discovery requires understanding host-pathogen interactions leading to biomarker expression. Here we report a systems immunology approach integrating clinical data and bacterial metabolic and regulatory information with high-throughput detection in human serum of antibodies to the entire Mycobacterium tuberculosis proteome. Sera from worldwide TB suspects recognized approximately 10% of the bacterial proteome. This result defines the M. tuberculosis immunoproteome, which is rich in membrane-associated and extracellular proteins. Additional analyses revealed that during active tuberculosis (i) antibody responses focused on an approximately 0.5% of the proteome enriched for extracellular proteins, (ii) relative target preference varied among patients, and (iii) responses correlated with bacillary burden. These results indicate that the B cell response tracks the evolution of infection and the pathogen burden and replicative state and suggest functions associated with B cell-rich foci seen in tuberculous lung granulomas. Our integrated proteome-scale approach is applicable to other chronic infections characterized by diverse antibody target recognition.
- Published
- 2010
- Full Text
- View/download PDF
24. Mutational analysis of the human 2B4 (CD244)/CD48 interaction: Lys68 and Glu70 in the V domain of 2B4 are critical for CD48 binding and functional activation of NK cells.
- Author
-
Mathew SO, Kumaresan PR, Lee JK, Huynh VT, and Mathew PA
- Subjects
- Alanine genetics, Amino Acid Sequence, Animals, Antigens, CD chemistry, Antigens, Surface chemistry, Antigens, Surface physiology, CD48 Antigen, DNA Mutational Analysis, Dimerization, Down-Regulation genetics, Down-Regulation immunology, Glutamic Acid metabolism, Humans, Immunosuppressive Agents antagonists & inhibitors, Immunosuppressive Agents chemistry, Immunosuppressive Agents metabolism, Killer Cells, Natural metabolism, Lymphocyte Activation immunology, Lysine metabolism, Melanoma, Experimental genetics, Melanoma, Experimental metabolism, Membrane Glycoproteins antagonists & inhibitors, Membrane Glycoproteins chemistry, Membrane Glycoproteins physiology, Mice, Molecular Sequence Data, Protein Binding genetics, Protein Binding immunology, Protein Structure, Tertiary genetics, Receptors, Immunologic antagonists & inhibitors, Receptors, Immunologic chemistry, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins metabolism, Signaling Lymphocytic Activation Molecule Family, Antigens, CD genetics, Antigens, CD metabolism, Antigens, Surface metabolism, Cytotoxicity, Immunologic genetics, Glutamic Acid genetics, Killer Cells, Natural immunology, Lymphocyte Activation genetics, Lysine genetics, Membrane Glycoproteins genetics, Membrane Glycoproteins metabolism, Receptors, Immunologic genetics, Receptors, Immunologic metabolism
- Abstract
Interaction between receptors and ligands plays a critical role in the generation of immune responses. The 2B4 (CD244), a member of the CD2 subset of the Ig superfamily, is the high affinity ligand for CD48. It is expressed on NK cells, T cells, monocytes, and basophils. Recent data indicate that 2B4/CD48 interactions regulate NK and T lymphocyte functions. In human NK cells, 2B4/CD48 interaction induces activation signals, whereas in murine NK cells it sends inhibitory signals. To determine the structural basis for 2B4/CD48 interaction, selected amino acid residues in the V domain of the human 2B4 (h2B4) were mutated to alanine by site-directed mutagenesis. Following transient expression of these mutants in B16F10 melanoma cells, their interaction with soluble CD48-Fc fusion protein was assessed by flow cytometry. We identified amino acid residues in the extracellular domain of h2B4 that are involved in interacting with CD48. Binding of CD48-Fc fusion protein to RNK-16 cells stably transfected with wild-type and a double-mutant Lys(68)Ala-Glu(70)Ala h2B4 further demonstrated that Lys(68) and Glu(70) in the V domain of h2B4 are essential for 2B4/CD48 interaction. Functional analysis indicated that Lys(68) and Glu(70) in the extracellular domain of h2B4 play a key role in the activation of human NK cells through 2B4/CD48 interaction.
- Published
- 2005
- Full Text
- View/download PDF
25. Gene knockdown of gamma-glutamylcysteine synthetase by RNAi in the parasitic protozoa Trypanosoma brucei demonstrates that it is an essential enzyme.
- Author
-
Huynh TT, Huynh VT, Harmon MA, and Phillips MA
- Subjects
- Animals, Base Sequence, Buthionine Sulfoximine pharmacology, Cell Death, DNA, Protozoan genetics, Enzyme Inhibitors pharmacology, Glutamate-Cysteine Ligase antagonists & inhibitors, Glutathione metabolism, RNA Interference, Spermidine metabolism, Sulfhydryl Compounds metabolism, Trypanosoma brucei brucei drug effects, Glutamate-Cysteine Ligase genetics, Glutamate-Cysteine Ligase metabolism, Glutathione analogs & derivatives, Spermidine analogs & derivatives, Trypanosoma brucei brucei enzymology, Trypanosoma brucei brucei genetics
- Abstract
The parasitic protozoa Trypanosoma brucei utilizes a novel cofactor (trypanothione, T(SH)2), which is a conjugate of GSH and spermidine, to maintain cellular redox balance. gamma-Glutamylcysteine synthetase (gamma-GCS) catalyzes the first step in the biosynthesis of GSH. To evaluate the importance of thiol metabolism to the parasite, RNAi methods were used to knock down gene expression of gamma-GCS in procyclic T. brucei cells. Induction of gamma-GCS RNAi with tetracycline led to cell death within 4-6 days post-induction. Cell death was preceded by the depletion of the gamma-GCS protein and RNA and by the loss of the cellular pools of GSH and T(SH)2. The addition of GSH (80 microM) to cell cultures rescued the RNAi cell death phenotype and restored the intracellular thiol pools to wild-type levels. Treatment of cells with buthionine sulfoximine (BSO), an enzyme-activated inhibitor of gamma-GCS, also resulted in cell death. However, the toxicity of the inhibitor was not reversed by GSH, suggesting that BSO has more than one cellular target. BSO depletes intracellular thiols to a similar extent as gamma-GCS RNAi; however, addition of GSH did not restore the pools of GSH and T(SH)2. These data suggest that BSO also acts to inhibit the transport of GSH or its peptide metabolites into the cell. The ability of BSO to inhibit both synthesis and transport of GSH likely makes it a more effective cytotoxic agent than an inhibitor with a single mode of action. Finally the potential for the T(SH)2 biosynthetic enzymes to be regulated in response to reduced thiol levels was studied. The expression levels of ornithine decarboxylase and of S-adenosylmethionine decarboxylase, two essential enzymes in spermidine biosynthesis, remained constant in induced gamma-GCS RNAi cell lines.
- Published
- 2003
- Full Text
- View/download PDF
26. Cunninghamella bertholletiae infection in a bone marrow transplant patient: amphotericin lung penetration, MIC determinations, and review of the literature.
- Author
-
Garey KW, Pendland SL, Huynh VT, Bunch TH, Jensen GM, and Pursell KJ
- Subjects
- Amphotericin B therapeutic use, Antifungal Agents therapeutic use, Cunninghamella pathogenicity, Humans, Lung Diseases, Fungal drug therapy, Male, Microbial Sensitivity Tests methods, Middle Aged, Mucormycosis drug therapy, Amphotericin B pharmacokinetics, Antifungal Agents pharmacokinetics, Bone Marrow Transplantation adverse effects, Cunninghamella drug effects, Lung Diseases, Fungal microbiology, Mucormycosis microbiology
- Abstract
Infections caused by Cunninghamella bertholletiae, an opportunistic fungal organism, have an extremely high mortality rate. A fatal case of C. bertholletiae fungal pneumonia occurred in a man who had received an allogeneic bone marrow transplant. Aggressive debridement and high-dose liposomal amphotericin B failed to eradicate the infection. Right lung tissue samples obtained during lobectomy were assayed for amphotericin B concentrations by high-performance liquid chromatography, and minimum inhibitory concentration (MIC) determinations of amphotericin B against C. bertholletiae were determined by the macrobroth dilution method. The MIC for the isolate of C. bertholletiae was 4 microg/ml. Amphotericin B lung concentrations averaged 9.5 microg/ml (range 3.7-13.8 microg/ml), with a corresponding serum trough concentration of 0.9 microg/ml. To our knowledge, this is the first reported case of amphotericin B concentrations measured at the site of infection in a patient with a pulmonary Cunninghamella infection, together with a corresponding MIC of the organism. The patient's death, which occurred despite aggressive debridement and high amphotericin B lung concentrations, highlights the need for novel strategies to treat infections caused by invasive molds such as C. bertholletiae.
- Published
- 2001
- Full Text
- View/download PDF
27. Polymorphism in the 2B4 gene of inbred mouse strains.
- Author
-
Kumaresan PR, Huynh VT, and Mathew PA
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Immunoglobulin Variable Region genetics, Mice, Mice, Inbred BALB C, Mice, Inbred Strains, Molecular Sequence Data, Sequence Homology, Amino Acid, Signaling Lymphocytic Activation Molecule Family, Antigens, CD, Membrane Glycoproteins genetics, Polymorphism, Genetic, Receptors, Immunologic
- Published
- 2000
- Full Text
- View/download PDF
28. A pharmacokinetic and pharmacodynamic study of artesunate for vivax malaria.
- Author
-
Batty KT, Le AT, Ilett KF, Nguyen PT, Powell SM, Nguyen CH, Truong XM, Vuong VC, Huynh VT, Tran QB, Nguyen VM, and Davis TM
- Subjects
- Administration, Oral, Adult, Animals, Antimalarials administration & dosage, Artesunate, Biological Availability, Cross-Over Studies, Half-Life, Humans, Injections, Intravenous, Malaria, Vivax parasitology, Male, Parasitemia drug therapy, Parasitemia metabolism, Parasitemia parasitology, Plasmodium vivax drug effects, Plasmodium vivax growth & development, Plasmodium vivax isolation & purification, Sesquiterpenes administration & dosage, Vietnam, Antimalarials pharmacokinetics, Antimalarials pharmacology, Artemisinins, Malaria, Vivax drug therapy, Malaria, Vivax metabolism, Sesquiterpenes pharmacokinetics, Sesquiterpenes pharmacology
- Abstract
To investigate the pharmacokinetic and pharmacodynamic properties of artesunate (ARTS) and its active metabolite dihydroartemisinin (DHA) in Plasmodium vivax infections, 12 male Vietnamese adults with slide-positive vivax malaria received either intravenous ARTS (120 mg; group 1) or oral ARTS (100 mg; group 2) with the alternative preparation given 8 hr later in a randomized, open, cross-over study. Following intravenous injection, ARTS had a peak plasma drug concentration (Cmax) of 35.6 microM (13.7 mg/L), an elimination half-life (t1/2) of 2.2 min, a clearance (CL) of 3.0 L/hr/kg, and a volume of distribution (V) of 0.16 L/kg. Dihydroartemisinin had a Cmax of 7.7 microM (2.2 mg/L), a tmax of 8 min, a t1/2 of 37 min, an apparent CL of 1.1 L/hr/kg, and an apparent V of 0.9 L/kg. Following oral ARTS, the mean relative bioavailability of DHA was 85%, the Cmax was 3.0 microM (0.85 mg/L), the tmax was 75 min, and t1/2 was 40 min. The mean time to 50% reduction in the parasite count (PCT50) and median fever clearance time were 3 hr and 16 hr, respectively. Following intravenous ARTS (group 1), the PCT50 for total parasites, rings, trophozoites, and gametocytes was 3.3 hr, 3.2 hr, 4.0 hr, and 3.6 hr, respectively. This study confirms that ARTS is effective against P. vivax, with rapid clearance of sexual and asexual forms of the parasite. Artesunate is a suitable initial treatment for vivax malaria, or when the plasmodial species cannot be reliably identified.
- Published
- 1998
- Full Text
- View/download PDF
29. Human immunodeficiency virus type 1 and its coat protein gp120 induce apoptosis and activate JNK and ERK mitogen-activated protein kinases in human neurons.
- Author
-
Lannuzel A, Barnier JV, Hery C, Huynh VT, Guibert B, Gray F, Vincent JD, and Tardieu M
- Subjects
- Astrocytes enzymology, Astrocytes pathology, Cells, Cultured, Embryo, Mammalian, Enzyme Activation, Humans, MAP Kinase Kinase 4, Microglia enzymology, Microglia pathology, Phosphorylation, Signal Transduction, Time Factors, AIDS Dementia Complex enzymology, AIDS Dementia Complex pathology, Apoptosis, Calcium-Calmodulin-Dependent Protein Kinases metabolism, HIV Envelope Protein gp120 metabolism, HIV-1 metabolism, JNK Mitogen-Activated Protein Kinases, Mitogen-Activated Protein Kinase Kinases, Mitogen-Activated Protein Kinases metabolism, Nerve Tissue Proteins metabolism, Neurons enzymology, Neurons pathology, Protein Kinases metabolism
- Abstract
Detection of apoptotic neurons and microglial cells in the brains of human immunodeficiency virus type 1 (HIV-1)-infected patients has suggested that programmed cell death may be implicated in the physiopathology of HIV-1 encephalopathy. To analyze in vitro the intracellular signals induced by HIV-1 in human neurons and the associated neuronal death, we tested cultured human central nervous system (CNS) cells for apoptosis induced by HIV-1 and gp120 and for signaling pathways activated by gp120. HIV-1 and gp120 induced apoptosis of neurons and microglial cells but not of astrocytes or transformed microglial cells. Gp120 activated c-Jun N-terminal kinase (JNK) and p42 extracellular-regulated kinase (ERK) in primary CNS cells, with an early peak of activation at 2 to 5 minutes that was not present when pure microglial or astrocyte cultures were tested, followed by a late and sustained activation (10 and 60 minutes) in primary and enriched glial cell cultures as well as in transformed microglial cells. This demonstrates that gp120 could be an effector of HIV-1-induced apoptosis in the CNS and act directly on neuronal and glial cells.
- Published
- 1997
- Full Text
- View/download PDF
30. An HSP60-63 homologue is constitutively expressed in infective larvae of Trichinella spiralis.
- Author
-
Allegretti S, Hambourg C, Huynh VT, and Dupouy-Camet J
- Subjects
- Animals, Antibodies, Helminth blood, Blotting, Western, Fluorescent Antibody Technique, Humans, Larva, Sequence Homology, Amino Acid, Trichinella spiralis pathogenicity, Chaperonin 60 metabolism, Trichinella spiralis genetics
- Abstract
Western-blot analysis of Trichinella spiralis proteins were carried out with anti-HSP60-63 and anti-HSP90 antibodies. These experiments showed the presence of an homologue of HSP60-63 but no HSP90 homologue could be identified. Image analysis showed that HSP60-63 represented approximatively 4% of the Thichinella proteic preparation. Immunofluorescence analysis on cryosections of infected muscles showed the presence of HSP60-63 throughout the body wall (except in the cuticle) and in digestive structures. On some sections, patches of fluorescence could be seen on the inner surface of the nurse cell membrane. In addition, the western-blot analysis of sera from two patients − out of 10 tested − showed antibodies against HSP60-63 recombinant proteins.
- Published
- 1997
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.