Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
Add more filters










Publication year range
1.
BMJ Open ; 10(7): e034156, 2020 07 05.
Article in English | MEDLINE | ID: mdl-32624467

ABSTRACT

OBJECTIVE: This study developed a surveillance system suitable for monitoring epidemic outbreaks and assessing public opinion in non-English-speaking countries. We evaluated whether social media reflects social uneasiness and fear during epidemic outbreaks and natural catastrophes. DESIGN: Cross-sectional study. SETTING: Freely available epidemic data in Taiwan. MAIN OUTCOME MEASURE: We used weekly epidemic incidence data obtained from the Taiwan Centers for Disease Control and online search query data obtained from Google Trends between 4 October 2015 and 2 April 2016. To validate whether non-English query keywords were useful surveillance tools, we estimated the correlation between online query data and epidemic incidence in Taiwan. RESULTS: With our approach, we noted that keywords ('common cold'), ('fever') and ('cough') exhibited good to excellent correlation between Google Trends query data and influenza incidence (r=0.898, p<0.001; r=0.773, p<0.001; r=0.796, p<0.001, respectively). They also displayed high correlation with influenza-like illness emergencies (r=0.900, p<0.001; r=0.802, p<0.001; r=0.886, p<0.001, respectively) and outpatient visits (r=0.889, p<0.001; r=0.791, p<0.001; r=0.870, p<0.001, respectively). We noted that the query ('enterovirus') exhibited excellent correlation with the number of enterovirus-infected patients in emergency departments (r=0.914, p<0.001). CONCLUSIONS: These results suggested that Google Trends can be a good surveillance tool for epidemic outbreaks, even in Taiwan, the non-English-speaking country. Online search activity indicates that people are concerned about epidemic diseases, even if they do not visit hospitals. This prompted us to develop useful tools to monitor social media during an epidemic because such media usage reflects infectious disease trends more quickly than does traditional reporting.


Subject(s)
Epidemics , Language , Cross-Sectional Studies , Disease Outbreaks , Humans , Internet , Search Engine , Taiwan/epidemiology
2.
Photodiagnosis Photodyn Ther ; 23: 111-118, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29894822

ABSTRACT

Photodynamic therapy (PDT) is a treatment utilizing the combined action of photosensitizers and light for the treatment of various cancers. The mechanisms for tumor destruction after PDT include direct tumor cell kill by singlet oxygen species (OS), indirect cell kill via vascular damage, and an elicited immune response. However, it has been reported that many cellular activators, including vascular endothelial growth factor (VEGF), are produced by tumor cells after PDT. In this study, we demonstrate that meta-tetra(hydroxyphenyl) chlorin (mTHPC)-based photodynamic therapy combined with bevacizumab (Avastin™), an anti-VEGF neutralizing monoclonal antibody that blocks the binding of VEGF to its receptor, can enhance the effectiveness of each treatment modality. We evaluated the efficacy of bevacizumab-based anti-angiogenesis in combination with PDT as well as the resulting VEGF levels and microvessel density (MVD) in a mouse model of human colon cancer. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were performed to assess VEGF concentrations and microvessel density in the various treatment groups, and confocal imaging and high performance liquid chromatography (HPLC) analyses were used to measure the distribution and concentration of mTHPC in tumors. Our results demonstrate that combination of PDT followed by bevacizumab significantly elicits a greater tumor response whereas bevacizumab treatment prior to PDT led to a reduced tumor response. Immunostaining and ELISA analyses revealed a lower expression of VEGF in tumors treated with combination therapy of PDT followed by bevacizumab. However, bevacizumab treatment decreased the accumulation of mTHPC in tumors 24 h after administration, which complemented the results of decreased anti-tumor efficacy of bevacizumab followed by PDT.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Bevacizumab/pharmacology , Colorectal Neoplasms/drug therapy , Mesoporphyrins/pharmacology , Photosensitizing Agents/pharmacology , Animals , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Therapy, Combination , Enzyme-Linked Immunosorbent Assay , Female , Kaplan-Meier Estimate , Mesoporphyrins/administration & dosage , Mice , Mice, Inbred BALB C , Neovascularization, Pathologic/drug therapy , Photochemotherapy/methods , Photosensitizing Agents/administration & dosage , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Tumor Burden , Vascular Endothelial Growth Factor A/metabolism
4.
Biomaterials ; 101: 241-50, 2016 09.
Article in English | MEDLINE | ID: mdl-27294541

ABSTRACT

Combination chemotherapy with multiple drugs commonly requires several injections on various schedules, and the probability that the drug molecules reach the diseased tissues at the proper time and effective therapeutic concentrations is very low. This work elucidates an injectable co-delivery system that is based on cationic liposomes that are adsorbed on anionic hollow microspheres (Lipos-HMs) via electrostatic interaction, from which the localized sequence-specific release of a chemopreventive agent (1,25(OH)2D3) and an anticancer drug (doxorubicin; DOX) can be thermally driven in a time-controllable manner by an externally applied high-frequency magnetic field (HFMF). Lipos-HMs can greatly promote the accumulation of reactive oxygen species (ROS) in tumor cells by reducing their cytoplasmic expression of an antioxidant enzyme (superoxide dismutase) by 1,25(OH)2D3, increasing the susceptibility of cancer cells to the cytotoxic action of DOX. In nude mice that bear xenograft tumors, treatment with Lipos-HMs under exposure to HFMF effectively inhibits tumor growth and is the most effective therapeutic intervention among all the investigated. These empirical results demonstrate that the synergistic anticancer effects of sequential release of 1,25(OH)2D3 and DOX from the Lipos-HMs may have potential for maximizing DOX cytotoxicity, supporting more effective cancer treatment.


Subject(s)
Antineoplastic Agents/administration & dosage , Breast Neoplasms/drug therapy , Calcitriol/administration & dosage , Delayed-Action Preparations/chemistry , Doxorubicin/administration & dosage , Animals , Antineoplastic Agents/therapeutic use , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Calcitriol/therapeutic use , Cell Survival/drug effects , Doxorubicin/therapeutic use , Female , Humans , Liposomes/chemistry , MCF-7 Cells , Magnetic Fields , Mice, Inbred BALB C , Mice, Nude , Reactive Oxygen Species/metabolism , Superoxide Dismutase/metabolism
5.
J Control Release ; 199: 53-62, 2015 Feb 10.
Article in English | MEDLINE | ID: mdl-25499553

ABSTRACT

Eradicating subcutaneous bacterial infections remains a significant challenge. This work reports an injectable system of hollow microspheres (HMs) that can rapidly produce localized heat activated by near-infrared (NIR) light and control the release of an antibiotic via a "molecular switch" in their polymer shells, as a combination strategy for treating subcutaneous abscesses. The HMs have a shell of poly(d,l-lactic-co-glycolic acid) (PLGA) and an aqueous core that is comprised of vancomycin (Van) and polypyrrole nanoparticles (PPy NPs), which are photothermal agents. Experimental results demonstrate that the micro-HMs ensure efficiently the spatial stabilization of their encapsulated Van and PPy NPs at the injection site in mice with subcutaneous abscesses. Without NIR irradiation, the HMs elute a negligible drug concentration, but release substantially more when exposed to NIR light, suggesting that this system is suitable as a photothermally-responsive drug delivery system. The combination of photothermally-induced hyperthermia and antibiotic therapy with HMs increases cytotoxicity for bacteria in abscesses, to an extent that is greater than the sum of the two treatments alone, demonstrating a synergistic effect. This treatment platform may find other clinical applications, especially for localized hyperthermia-based cancer therapy.


Subject(s)
Abscess/therapy , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/therapeutic use , Drug Delivery Systems , Skin Diseases/therapy , Abscess/drug therapy , Animals , Anti-Bacterial Agents/pharmacology , Hot Temperature , Infrared Rays , Injections, Subcutaneous , Lactic Acid , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice , Mice, Inbred BALB C , Microspheres , Nanoparticles , Photochemistry , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer , Pyrroles , Skin Diseases/drug therapy , Tissue Distribution , Vancomycin/administration & dosage , Vancomycin/pharmacology , Vancomycin/therapeutic use , Wound Healing/drug effects
6.
Small ; 10(20): 4100-5, 2014 Oct 29.
Article in English | MEDLINE | ID: mdl-24976002

ABSTRACT

Treating inflammation with a dual-switch-controlled release system: The release of a drug from the developed microbead system occurs only in response to both an increase in local temperature and an acidic environmental pH. This dual-switch-controlled release system has the advantages of distinguishing between inflamed and healthy tissues to improve treatment efficacy.


Subject(s)
Drug Delivery Systems , Hydrogen-Ion Concentration , Microspheres , Microscopy, Confocal , Microscopy, Electron, Scanning
7.
ACS Nano ; 8(2): 1213-21, 2014 Feb 25.
Article in English | MEDLINE | ID: mdl-24386907

ABSTRACT

Oxidative stress and reduced pH are involved in many inflammatory diseases. This study describes a nanoparticle-based system that is responsive to both oxidative stress and reduced pH in an inflammatory environment to effectively release its encapsulated curcumin, an immune-modulatory agent with potent anti-inflammatory and antioxidant capabilities. Because of the presence of Förster resonance energy transfer between curcumin and the carrier, this system also allowed us to monitor the intracellular release behavior. The curcumin released upon triggering could efficiently reduce the excess oxidants produced by the lipopolysaccharide (LPS)-stimulated macrophages. The feasibility of using the curcumin-loaded nanoparticles for anti-inflammatory applications was further validated in a mouse model with ankle inflammation induced by LPS. The results of these studies demonstrate that the proposed nanoparticle system is promising for treating oxidative stress-related diseases.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Drug Carriers , Hydrogen-Ion Concentration , Nanoparticles , Oxidative Stress
8.
Biomaterials ; 34(1): 1-10, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23044041

ABSTRACT

Chemotherapy research highly prioritizes overcoming the multi-drug resistance (MDR) effect in cancer cells. To overcome the drug efflux mediated by P-glycoprotein (P-gp) transporters, we developed pH-responsive poly(D,L-lactic-co-glycolic acid) hollow particles (PLGA HPs), capable of delivering doxorubicin (DOX) into MDR cells (MCF-7/ADR). The shell wall of PLGA HPs contained DiO (a hydrophobic dye), and their aqueous core carried DOX hydrochloride salt and sodium bicarbonate, a gas-generating agent when present in acidic environments. Both DiO and DOX could serve as fluorescence probes to localize HPs and visualize their intracellular drug release in real-time. Real-time confocal images provided visible evidences of the acid-responsive intracellular release of DOX from PLGA HPs in MDR cells. Via the macropinocytosis pathway, PLGA HPs taken up by cells experienced an increasingly acidic environment as they trafficked through the early endosomes and then matured into more acidic late endosomes/lysosomes. The progressive acidification of the internalized particles in the late endosomes/lysosomes generated CO(2) bubbles, leading to the disruption of HPs, prompt release of DOX, its accumulation in the nuclei, and finally the death of MDR cells. Conversely, taken up via a passive diffusion mechanism, free DOX was found mainly at the perimembrane region and barely reached the cell nuclei; therefore, no apparent cytotoxicity was observed. These results suggest that the developed PLGA HPs were less susceptible to the P-gp-mediated drug efflux in MDR cells and is a highly promising approach in chemotherapy.


Subject(s)
Computer Systems , Drug Resistance, Multiple , Gases/chemistry , Lactic Acid/chemistry , Nanoparticles/chemistry , Organelles/metabolism , Polyglycolic Acid/chemistry , Cell Death/drug effects , Cell Survival/drug effects , Doxorubicin/chemistry , Doxorubicin/pharmacology , Drug Resistance, Multiple/drug effects , Endocytosis/drug effects , Flow Cytometry , Humans , Hydrogen-Ion Concentration/drug effects , Image Processing, Computer-Assisted , Intracellular Space/drug effects , Intracellular Space/metabolism , MCF-7 Cells , Microscopy, Confocal , Nanoparticles/ultrastructure , Organelles/drug effects , Polylactic Acid-Polyglycolic Acid Copolymer , X-Ray Diffraction
9.
Small ; 8(23): 3584-8, 2012 Dec 07.
Article in English | MEDLINE | ID: mdl-22893436

ABSTRACT

Pulsatile release: When a high-frequency magnetic field is applied, heat will be generated by coupling to the iron oxide nanoparticles encapsulated in the shells of PLGA hollow microspheres. As the temperature approaches the T(g) of PLGA, the polymer chains become more mobile, subsequently increasing the free volume of PLGA matrix and significantly enhancing the diffusion of drug molecules.


Subject(s)
Antineoplastic Agents/chemistry , Doxorubicin/chemistry , Lactic Acid/chemistry , Microspheres , Polyglycolic Acid/chemistry , Chemistry, Pharmaceutical , Drug Carriers , Ferric Compounds/chemistry , Magnetic Fields , Nanoparticles , Particle Size , Permeability , Polylactic Acid-Polyglycolic Acid Copolymer , Pulsatile Flow , Temperature
10.
Biomaterials ; 33(20): 5156-65, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22484044

ABSTRACT

This work presents an approach to codelivering transdermally two model drugs, Alexa 488 and Cy5, in sequence, based on a system of polyvinylpyrrolidone microneedles (PVP MNs) that contain pH-responsive poly(d,l-lactic-co-glycolic acid) hollow microspheres (PLGA HMs). The MN system provides the green fluorescence of Alexa 488 in PVP MNs, the red fluorescence of the DiI-labeled PLGA shell of HMs, and the cyan fluorescence of Cy5 in their aqueous core. Combined together, the prepared MN arrays support the localization of the HMs and the monitoring of the release profiles of model drugs within the skin tissues. The key component of this system is NaHCO(3), which can be easily incorporated into HMs. After HMs are treated with an acidic solution (simulating the skin pH environment), protons (H(+)) can rapidly diffuse through the free volume in the PLGA shells to react with NaHCO(3) and form a large number of CO(2) bubbles. This effect generates pressure inside the HMs and creates pores inside their PLGA shells, releasing the encapsulated Cy5. Test MNs were strong enough to be inserted into rat skin without breaking. The PVP MNs were significantly dissolved within minutes, and the first model drug Alexa 488, together with HMs, were successfully deposited into the tissues. Once in the acidic environment of the skin, the released HMs started to release Cy5 and continued to spread throughout the neighboring tissues, in a second step of the release of the drug. This approach can be used clinically to codeliver sequentially and transcutaneously a broad range of drugs.


Subject(s)
Lactic Acid/chemistry , Microspheres , Needles , Polyglycolic Acid/chemistry , Animals , Dimethylpolysiloxanes , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Polylactic Acid-Polyglycolic Acid Copolymer , Rats , Sodium Bicarbonate/chemistry
11.
Angew Chem Int Ed Engl ; 50(35): 8086-9, 2011 Aug 22.
Article in English | MEDLINE | ID: mdl-21751316

ABSTRACT

Prepared to self-destruct: when poly(D, L-lactic-co-glycolic acid) (PLGA) hollow microspheres containing NaHCO(3) entered the endocytic organelles of a live cell, the NaHCO(3) in the aqueous core reacted with protons that infiltrated from the compartment to generate CO(2) gas. The evolution of CO(2) bubbles led to the formation of small holes in the PLGA shell and thus rapid release of the encapsulated drug doxorubicin.


Subject(s)
Lysosomes/chemistry , Microspheres , Pharmaceutical Preparations/chemistry , Cell Line, Tumor , Cell Survival/drug effects , Doxorubicin/chemistry , Doxorubicin/toxicity , Drug Carriers/chemistry , Humans , Hydrogen-Ion Concentration , Lactic Acid/chemistry , Lysosomes/metabolism , Polyglycolic Acid/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Sodium Bicarbonate/chemistry
12.
Mol Pharm ; 7(4): 1244-53, 2010 Aug 02.
Article in English | MEDLINE | ID: mdl-20469890

ABSTRACT

Photodynamic therapy (PDT) is a light-induced chemical reaction that produces localized tissue damage for the treatment of cancers and other nonmalignant conditions. The activation of photosensitizers in a target tissue is accomplished with a specific light source in the presence of molecular oxygen. In the clinic, patients treated with PDT should be kept away from direct sunlight or strong indoor lighting to avoid skin phototoxicity. In this study, a photosensitizer encapsulated within a micelle was developed to overcome this problem. The pH-sensitive micelles were successfully incorporated with meta-tetra(hydroxyphenyl)chlorin (m-THPC), and the cytotoxicity and antitumor effects were investigated in vitro and in vivo. Our results demonstrated that PDT with m-THPC-loaded micelles had no significant adverse effects on the body weight of mice in vivo. Furthermore, after an extended delivery time, m-THPC-loaded micelles and free m-THPC had similar antitumor effects, but the m-THPC-loaded micelles had less skin phototoxicity. Thus, this strategy could be used as a potential nanocarrier for PDT-mediated cancer therapy.


Subject(s)
Mesoporphyrins/therapeutic use , Micelles , Oxazoles/chemistry , Polyesters/chemistry , Polymers/chemistry , Skin/drug effects , Skin/radiation effects , Animals , Cell Line, Tumor , Female , HT29 Cells , Humans , Mesoporphyrins/chemistry , Mice , Mice, Inbred BALB C , Photochemotherapy/methods , Photosensitizing Agents/chemistry , Photosensitizing Agents/therapeutic use , Polyamines
SELECTION OF CITATIONS
SEARCH DETAIL
...