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BACKGROUND: Community-based integrated management of neonatal and childhood illness (CB-IMNCI) is a government-run priority one program aimed to decrease neonatal and childhood morbidity and mortality. The objective of our study was to identify the CB-IMNCI implementation gap in terms of health care providers' training status, availability of medicines, follow-up visits and clinical outcome at Primary Health Care Centers and Health Posts of Morang district of Nepal. METHODS: We conducted a community based cross-sectional study in Morang district of Nepal from 25 Oct 2021 to 25 Jan 2022. Ethical approval was taken from ethical review board of the Nepal Health Research Council. We enrolled 9 (53%) out of 17 local governments of Morang district of Nepal by simple random sampling. The collected data was entered in MS Excel and analyzed by SPSS version 23. RESULTS: The majority of healthcare workers were in their early age of 26-35 years (57.2%), male (85.7%) and Auxiliary Health Workers (78.6%). The mean duration of practice was 15.1 years. Only 46.5% of healthcare providers were trained for the CB-IMNCI program. The availability of medicine as per CB-IMNCI guideline was 52.9%. There was no record available for total number of required follow up, total number of actual follow up and clinical outcome in last 6 months. CONCLUSIONS: About half of the human resources were trained with the availability of only half of the required medicines. We also found a lack of adequate record-keeping of follow up of patients and their clinical outcomes.
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Serviços de Saúde da Criança , Criança , Recém-Nascido , Humanos , Masculino , Adulto , Estudos Transversais , Nepal , Agentes Comunitários de Saúde/educação , Atenção Primária à SaúdeRESUMO
BACKGROUND: Etiology of and outcomes following idiosyncratic drug-induced liver injury (DILI) vary geographically. We conducted a prospective study of DILI in India, from 2013 to 2018 and summarize the causes, clinical features, outcomes and predictors of mortality. METHODS: We enrolled patients with DILI using international DILI expert working group criteria and Roussel Uclaf causality assessment method. Follow-up was up to 3 months from onset of DILI or until death. Multivariate logistics regression was carried out to determine predictors of non-survival. RESULTS: Among 1288 patients with idiosyncratic DILI, 51.4% were male, 68% developed jaundice, 68% required hospitalization and 8.2% had co-existing HIV infection. Concomitant features of skin reaction, ascites, and encephalopathy (HE) were seen in 19.5%, 16.4%, and 10% respectively. 32.4% had severe disease. Mean MELD score at presentation was 18.8 ± 8.8. Overall mortality was 12.3%; 65% in those with HE, 17.6% in patients who fulfilled Hy's law, and 16.6% in those that developed jaundice. Combination anti-TB drugs (ATD) 46.4%, complementary and alternative medicines (CAM) 13.9%, anti-epileptic drugs (AED) 8.1%, non-ATD antimicrobials 6.5%, anti-metabolites 3.8%, anti-retroviral drugs (ART)3.5%, NSAID2.6%, hormones 2.5%, and statins 1.4% were the top 9 causes. Univariate analysis identified, ascites, HE, serum albumin, bilirubin, creatinine, INR, MELD score (p < 0.001), transaminases (p < 0.04), and anti-TB drugs (p = 0.02) as predictors of non-survival. Only serum creatinine (p = 0.017), INR (p < 0.001), HE (p < 0.001), and ascites (p = 0.008), were significantly associated with mortality on multivariate analysis. ROC yielded a C-statistic of 0.811 for MELD and 0.892 for combination of serum creatinine, INR, ascites and HE. More than 50 different agents were associated with DILI. Mortality varied by drug class: 15% with ATD, 13.6% with CAM, 15.5% with AED, 5.8% with antibiotics. CONCLUSION: In India, ATD, CAM, AED, anti-metabolites and ART account for the majority of cases of DILI. The 3-month mortality was approximately 12%. Hy's law, presence of jaundice or MELD were predictors of mortality.
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Glioblastoma Multiforme is a deadly cancer of glial cells with very low survival rates. Current treatment options are invasive and have serious side effects. Single drug treatments make the tumor refractory after a certain period. Combination therapies have shown improvements in treatment responses against aggressive forms of cancer and are becoming a mainstay in the management of cancer. The purpose of this study is to design a combinatorial treatment regimen by engineering desired ratios of two different small molecule drugs (gefitinib and GSK461364A) in a single carrier that can reduce off-target effects and increase their bioavailability. Synergistic effects were observed with our formulation when optimal ratios of gefitinib and GSK461364A were loaded in poly (lactic-co-glycolic) acid and polyethylene glycol (PLGA-PEG) nanoparticles and tested for efficacy in U87-malignant glioma (U87-MG) cells. Combination nanoparticles proved to be more effective compared to single drug encapsulated nanoparticles, free drug combinations, and the mixture of two single loaded nanoparticles, with statistically significant values at certain ratios and drug concentrations. We also observed drastically reduced clonogenic potential of the cells that were treated with free drugs and nanoparticle combinations in a colony forming assay. From our findings, we conclude that the combination of GSK461364A and higher concentrations of gefitinib when encapsulated in nanoparticles yield synergistic killing of glioma cells. This study could form the basis for designing new combination treatments using nanoparticles to deliver multiple drugs to cancer cells for synergistic effects.
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Polymer-based nanoparticles (NPs) are useful vehicles in treating glioblastoma because of their favorable characteristics such as small size and ability to cross the bloodâ»brain barrier, as well as reduced immunogenicity and side effects. The use of a photosensitizer drug such as Verteporfin (BPD), in combination with a pan-vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI), Cediranib (CED), encapsulated in NPs will provide the medical field with new research on the possible ways to treat glioblastoma. Concomitant administration of BPD and CED NPs have the potential to induce dual photocytotoxic and cytostatic effects in U87 MG cells by (1) remotely triggering BPD through photodynamic therapy by irradiating laser at 690 nm and subsequent production of reactive oxygen species and (2) inhibiting cell proliferation by VEGFR interference and growth factor signaling mechanisms which may allow for longer progression free survival in patients and fewer systemic side effects. The specific aims of this research were to synthesize, characterize and assess cell viability and drug interactions for polyethylene-glycolated (PEGylated) polymeric based CED and BPD NPs which were less than 100 nm in size for enhanced permeation and retention effects. Synergistic effects were found using the co-administered therapies compared to the individual drugs. The major goal of this research was to investigate a new combination of photodynamic-chemotherapy drugs in nano-formulation for increased efficacy in glioblastoma treatment at reduced concentrations of therapeutics for enhanced drug delivery in vitro.
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Glioblastoma Multiforme (GBM) is a common primary brain cancer with a poor prognosis and a median survival of less than 14 months. Current modes of treatment are associated with deleterious side effects that reduce the life span of the patients. Nanomedicine enables site-specific delivery of active pharmaceutical ingredients and facilitates entrapment inside the tumor. Polo-like kinase 1 (PLK-1) inhibitors have shown promising results in tumor cells. GSK461364A (GSK) is one such targeted inhibitor with reported toxicity issues in phase 1 clinical trials. We have demonstrated in our study that the action of GSK is time dependent across all concentrations. There is a distinct 15-20% decrease in cell viability via apoptosis in U87-MG cells dosed with GSK at low concentrations (within the nanomolar and lower micromolar range) compared to higher concentrations of the drug. Additionally, we have confirmed that PLGA-PEG nanoparticles (NPs) containing GSK have shown significant reduction in cell viability of tumor cells compared to their free equivalents. Thus, this polymeric nanoconstruct encapsulating GSK can be effective even at low concentrations and could improve the effectiveness of the drug while reducing side effects at the lower effective dose. This is the first study to report a PLK-1 inhibitor (GSK) encapsulated in a nanocarrier for cancer applications.
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Triple-negative breast cancer (TNBC) has the worst prognosis among all subtypes of breast cancer. Currently, no targeted treatment has been approved for TNBC. The goal of this study was to design a remotely triggered, targeted therapy for TNBC using polymeric nanoparticles and light. Active targeting of TNBC was achieved by conjugating the nanoparticles to a peptide (hTf) that binds to the transferrin receptor, which is overexpressed in TNBC. Photodynamic therapy (PDT) was explored for TNBC treatment by remotely triggering benzoporphyrin derivative monoacid (BPD), a photosensitizer, using near-infrared light. In this study, we investigated the use of actively targeting polymeric nanoparticles for PDT against TNBC using in vitro imaging and cytotoxicity studies. Fluorescence imaging confirmed that the BPD-loaded nanoparticles showed greater fluorescence in TNBC cells compared to free BPD, but more importantly, actively targeted nanoparticles displayed stronger fluorescence compared to passively targeted nanoparticles. Moreover, fluorescence imaging following competition with empty targeted nanoparticles validated the specificity of the targeted nanoparticles for TNBC cells. The PDT killing results were in line with the fluorescence imaging results, where actively targeting nanoparticles exhibited the highest phototriggered cytotoxicity in TNBC cells, making them an attractive nanoplatform for TNBC treatment.
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Sistemas de Liberação de Medicamentos , Nanopartículas/química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Polímeros/química , Transferrina/química , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Verteporfina/uso terapêutico , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Microscopia de Fluorescência , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/farmacologia , Neoplasias de Mama Triplo Negativas/patologia , Verteporfina/administração & dosagem , Verteporfina/química , Verteporfina/farmacologiaRESUMO
Cancer continues to be one of the most difficult global healthcare problems. Although there is a large library of drugs that can be used in cancer treatment, the problem is selectively killing all the cancer cells while reducing collateral toxicity to healthy cells. There are several biological barriers to effective drug delivery in cancer such as renal, hepatic, or immune clearance. Nanoparticles loaded with drugs can be designed to overcome these biological barriers to improve efficacy while reducing morbidity. Nanomedicine has ushered in a new era for drug delivery by improving the therapeutic indices of the active pharmaceutical ingredients engineered within nanoparticles. First generation nanomedicines have received widespread clinical approval over the past two decades, from Doxil® (liposomal doxorubicin) in 1995 to Onivyde® (liposomal irinotecan) in 2015. This review highlights the biological barriers to effective drug delivery in cancer, emphasizing the need for nanoparticles for improving therapeutic outcomes. A summary of different nanoparticles used for drug delivery applications in cancer are presented. The review summarizes recent successes in cancer nanomedicine in the clinic. The clinical trials of Onivyde leading to its approval in 2015 by the Food and Drug Adminstration are highlighted as a case study in the recent clinical success of nanomedicine against cancer. Next generation nanomedicines need to be better targeted to specifically destroy cancerous tissue, but face several obstacles in their clinical development, including identification of appropriate biomarkers to target, scale-up of synthesis, and reproducible characterization. These hurdles need to be overcome through multidisciplinary collaborations across academia, pharmaceutical industry, and regulatory agencies in order to achieve the goal of eradicating cancer. This review discusses the current use of clinically approved nanomedicines, the investigation of nanomedicines in clinical trials, and the challenges that may hinder development of the nanomedicines for cancer treatment.
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Cancer cells have characteristics of acquired and intrinsic resistances to chemotherapy treatment-due to the hostile tumor microenvironment-that create a significant challenge for effective therapeutic regimens. Multidrug resistance, collateral toxicity to normal cells, and detrimental systemic side effects present significant obstacles, necessitating alternative and safer treatment strategies. Traditional administration of chemotherapeutics has demonstrated minimal success due to the non-specificity of action, uptake and rapid clearance by the immune system, and subsequent metabolic alteration and poor tumor penetration. Nanomedicine can provide a more effective approach to targeting cancer by focusing on the vascular, tissue, and cellular characteristics that are unique to solid tumors. Targeted methods of treatment using nanoparticles can decrease the likelihood of resistant clonal populations of cancerous cells. Dual encapsulation of chemotherapeutic drug allows simultaneous targeting of more than one characteristic of the tumor. Several first-generation, non-targeted nanomedicines have received clinical approval starting with Doxil® in 1995. However, more than two decades later, second-generation or targeted nanomedicines have yet to be approved for treatment despite promising results in pre-clinical studies. This review highlights recent studies using targeted nanoparticles for cancer treatment focusing on approaches that target either the tumor vasculature (referred to as 'vascular targeting'), the tumor microenvironment ('tissue targeting') or the individual cancer cells ('cellular targeting'). Recent studies combining these different targeting methods are also discussed in this review. Finally, this review summarizes some of the reasons for the lack of clinical success in the field of targeted nanomedicines.
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Cancer immunotherapy is a rapidly evolving and paradigm shifting treatment modality that adds a strong tool to the collective cancer treatment arsenal. It can be effective even for late stage diagnoses and has already received clinical approval. Tumors are known to not only avoid immune surveillance but also exploit the immune system to continue local tumor growth and metastasis. Because of this, most immunotherapies, particularly those directed against solid cancers, have thus far only benefited a small minority of patients. Early clinical substantiation lends weight to the claim that cancer immunotherapies, which are adaptive and enduring treatment methods, generate much more sustained and robust anticancer effects when they are effectively formulated in nanoparticles or scaffolds than when they are administered as free drugs. Engineering cancer immunotherapies using nanomaterials is, therefore, a very promising area worthy of further consideration and investigation. This review focuses on the recent advances in cancer immunoengineering using nanoparticles for enhancing the therapeutic efficacy of a diverse range of immunotherapies. The delivery of immunostimulatory agents to antitumor immune cells, such as dendritic or antigen presenting cells, may be a far more efficient tactic to eradicate tumors than delivery of conventional chemotherapeutic and cytotoxic drugs to cancer cells. In addition to its immense therapeutic potential, immunoengineering using nanoparticles also provides a valuable tool for unearthing and understanding the basics of tumor biology. Recent research using nanoparticles for cancer immunotherapy has demonstrated the advantage of physicochemical manipulation in improving the delivery of immunostimulatory agents. In vivo studies have tested a range of particle sizes, mostly less than 300 nm, and particles with both positive and negative zeta potentials for various applications. Material composition and surface modifications have been shown to contribute significantly in selective targeting, efficient delivery and active stimulation of immune system targets. Thus, these investigations, including a wide array of nanoparticles for cancer immunotherapy, substantiate the employment of nanocarriers for efficacious cancer immunotherapies.
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Nanotechnology has enabled the development of smart theranostic platforms that can concurrently diagnose disease, start primary treatment, monitor response, and, if required, initiate secondary treatments. Recent in vivo experiments demonstrate the promise of using theranostics in the clinic. In this paper, we review the use of remotely triggered theranostic nanoparticles for cancer applications, focusing heavily on advances in the past five years. Remote triggering mechanisms covered include photodynamic, photothermal, phototriggered chemotherapeutic release, ultrasound, electro-thermal, magneto-thermal, X-ray, and radiofrequency therapies. Each section includes a brief overview of the triggering mechanism and summarizes the variety of nanoparticles employed in each method. Emphasis in each category is placed on nano-theranostics with in vivo success. Some of the nanotheranostic platforms highlighted include photoactivatable multi-inhibitor nanoliposomes, plasmonic nanobubbles, reduced graphene oxide-iron oxide nanoparticles, photoswitching nanoparticles, multispectral optoacoustic tomography using indocyanine green, low temperature sensitive liposomes, and receptor-targeted iron oxide nanoparticles loaded with gemcitabine. The studies reviewed here provide strong evidence that the field of nanotheranostics is rapidly evolving. Such nanoplatforms may soon enable unique advances in the clinical management of cancer. However, reproducibility in the synthesis procedures of such "smart" platforms that lend themselves to easy scale-up in their manufacturing, as well as the development of new and improved models of cancer that are more predictive of human responses, need to happen soon for this field to make a rapid clinical impact.
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Triple Negative Breast Cancer (TNBC) continues to present a challenge in the clinic, as there is still no approved targeted therapy. TNBC is the worst sub-type of breast cancer in terms of prognosis and exhibits a deficiency in estrogen, progesterone, and human epidermal growth factor 2 (HER2) receptors. One possible option for the treatment of TNBC is chemotherapy. The issue with many chemotherapy drugs is that their effectiveness is diminished due to poor water solubility, and the method of administration directly or with a co-solvent intravenously can lead to an increase in toxicity. The issues of drug solubility can be avoided by using liposomes as a drug delivery carrier. Liposomes are engineered, biological nanoconstructs that possess the ability to encapsulate both hydrophobic and hydrophilic drugs and have been clinically approved to treat cancer. Specific targeting of cancer cell receptors through the use of ligands conjugated to the surface of drug-loaded liposomes could lessen damage to normal, healthy tissue. This study focuses on polyethylene glycol (PEG)-coated, folate conjugated, benzoporphyrin derivative (BPD)-loaded liposomes for treatment via photodynamic therapy (PDT). The folate receptor is over expressed on TNBC cells so these liposomes are targeted for greater uptake into cancer cells. PDT involves remotely irradiating light at 690 nm to trigger BPD, a hydrophobic photosensitive drug, to form reactive oxygen species that cause tumor cell death. BPD also displays a fluorescence signal when excited by light making it possible to image the fluorescence prior to PDT and for theranostics. In this study, free BPD, non-targeted and folate-targeted PEGylated BPD-loaded liposomes were introduced to a metastatic breast cancer cell line (MDA-MB-231) in vitro. The liposomes were reproducibly synthesized and characterized for size, polydispersity index (PDI), zeta potential, stability, and BPD release kinetics. Folate competition tests, fluorescence confocal imaging, and MTT assay were used to observe and quantify targeting effectiveness. The toxicity of BPD before and after PDT in monolayer and 3D in vitro cultures with TNBC cells was observed. This study may contribute to a novel nanoparticle-mediated approach to target TNBC using PDT.
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Cancer forms exhibiting poor prognosis have been extensively researched for therapeutic solutions. One of the conventional modes of treatment, chemotherapy shows inadequacy in its methodology due to imminent side-effects and acquired drug-resistance by cancer cells. However, advancements in nanotechnology have opened new frontiers to significantly alleviate collateral damage caused by current treatments via innovative delivery techniques, eliminating pitfalls encountered in conventional treatments. Properties like reduced drug-clearance and increased dose efficacy by the enhanced permeability and retention effect deem nanoparticles suitable for this application. Optimization of size, surface charge and surface modifications have provided nanoparticles with stealth properties capable of evading immune responses, thus deeming them as excellent carriers of chemotherapeutic agents. Biocompatible and biodegradable forms of polymers enhance the bioavailability of chemotherapeutic agents, and permit a sustained and time-dependent release of drugs which is a characteristic of their composition, thereby providing a controlled therapeutic approach. Studies conducted in vitro and animal models have also demonstrated a synergism in cytotoxicity given the mechanism of action of anticancer drugs when administered in combination providing promising results. Combination therapy has also shown implications in overcoming multiple-drug resistance, which can however be subdued by the adaptable nature of tumor microenvironment. Surface modifications with targeting moieties can therefore feasibly increase nanoparticle uptake by specific receptor-ligand interactions, increasing dose efficacy which can seemingly overcome drug-resistance. This article reviews recent trends and investigations in employing polymeric nanoparticles for effectively delivering combination chemotherapy, and modifications in delivery parameters enhancing dose efficacy, thus validating the potential in this approach for anticancer treatment.
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Cancer continues to remains a major healthcare problem across the world despite strong translational research efforts towards tackling the disease. Surgery, when possible, along with radiation and chemotherapy continue to remain the mainstay of cancer treatment. Novel targeted therapies or biologics and immunotherapies have recently been approved to improve treatment efficacies while reducing collateral damage to normal, non-cancerous tissues. Combination therapies have shown better results than individual monotherapies in the clinic but often the improvements in therapeutic indices remain marginal, at best. Several combinations treatments have been clinically approved for different types of cancer. Nanomedicine, the application of nanotechnology for medicine, has already made some positive impacts on the clinical care in this fight against cancer. Several nano-sized formulations of conventional chemotherapies have been clinically approved. Nanotechnology provides a novel way to deliver combination therapies with spatiotemporal control over drug release. This review explores the recent advances in nanotechnology-mediated combination treatments against cancer. Multifunctional nanomedicines for mechanism-based combination therapies are likely to deliver the right drugs to the right place at the right time for optimal treatment responses with reduced morbidity. No nanomedicine that combines two or more drugs in a single platform has been approved for clinical use yet. This is because several challenges still remain in the development of nano-combinations including but not limited to - the optimal drug ratios in these nanomedicines, control over these drug ratios over multiple batches, large scale, reproducible manufacturing of these nanomedicines and cost of these nano-combinations among others. These challenges need to be addressed soon using a multidisciplinary approach with collaborations between academia, the pharmaceutical industry and the regulatory bodies involved to ensure that nano-combination therapy delivers on its promise of better treatment outcomes while severely reducing morbidity thus improving the quality of life in cancer patients.
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Targeting molecular markers and pathways implicated in cancer cell growth is a promising avenue for developing effective therapies. Although the Ki-67 protein (pKi-67) is a key marker associated with aggressively proliferating cancer cells and poor prognosis, its full potential as a therapeutic target has never before been successfully shown. In this regard, its nuclear localization presents a major hurdle because of the need for intracellular and intranuclear delivery of targeting and therapeutic moieties. Using a liposomally encapsulated construct, we show for the first time the specific delivery of a Ki-67-directed antibody and subsequent light-triggered death in the human ovarian cancer cell line OVCAR-5. Photoimmunoconjugate-encapsulating liposomes (PICEL) were constructed from anti-pKi-67 antibodies conjugated to fluorescein 5(6)-isothiocyanate, as a photoactivatable agent, followed by encapsulation in noncationic liposomes. Nucleolar localization of the PICELs was confirmed by confocal imaging. Photodynamic activation with PICELs specifically killed pKi-67-positive cancer cells both in monolayer and in three-dimensional (3D) cultures of OVCAR-5 cells, with the antibody TuBB-9 targeting a physiologically active form of pKi-67 but not with MIB-1, directed to a different epitope. This is the first demonstration of (a) the exploitation of Ki-67 as a molecular target for therapy and (b) specific delivery of an antibody to the nucleolus in monolayer cancer cells and in an in vitro 3D model system. In view of the ubiquity of pKi-67 in proliferating cells in cancer and the specificity of targeting in 3D multicellular acini, these findings are promising and the approach merits further investigation.
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Anticorpos Monoclonais/farmacocinética , Nucléolo Celular/metabolismo , Antígeno Ki-67/imunologia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/química , Especificidade de Anticorpos/imunologia , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Epitopos/imunologia , Feminino , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/química , Humanos , Lipossomos/química , Microscopia Confocal , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologiaRESUMO
Theranostics, the fusion of therapy and diagnostics for optimizing efficacy and safety of therapeutic regimes, is a growing field that is paving the way towards the goal of personalized medicine for the benefit of patients. The use of light as a remote-activation mechanism for drug delivery has received increased attention due to its advantages in highly specific spatial and temporal control of compound release. Photo-triggered theranostic constructs could facilitate an entirely new category of clinical solutions which permit early recognition of the disease by enhancing contrast in various imaging modalities followed by the tailored guidance of therapy. Finally, such theranostic agents could aid imaging modalities in monitoring response to therapy. This article reviews recent developments in the use of light-triggered theranostic agents for simultaneous imaging and photoactivation of therapeutic agents. Specifically, we discuss recent developments in the use of theranostic agents for photodynamic-, photothermal- or photo-triggered chemotherapy for several diseases.
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Diagnóstico por Imagem/métodos , Infecções/diagnóstico , Infecções/tratamento farmacológico , Neoplasias/diagnóstico , Neoplasias/terapia , Fototerapia/métodos , Animais , Anti-Infecciosos/uso terapêutico , Antineoplásicos/uso terapêutico , Portadores de Fármacos/uso terapêutico , Humanos , Nanopartículas/uso terapêutico , Neoplasias/tratamento farmacológicoRESUMO
A murine model of cutaneous leishmaniasis with green fluorescent protein positive (GFP+) L. major enables the monitoring of parasitic load via measurements of GFP fluorescence intensity, allowing for a faster and more efficient way of monitoring the clinical outcome of photodynamic therapy (PDT). This model may provide new insights on the phototoxic aspects in PDT. Although PDT regimens may be somewhat different in humans, it is expected that the developed model will facilitate the optimization and clinical translation of PDT as a therapy for cutaneous leishmaniasis and the eventual development of topical PDT treatments for other granulomatous infections.
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Leishmania major/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Fenotiazinas/uso terapêutico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Calibragem , Modelos Animais de Doenças , Otopatias/tratamento farmacológico , Otopatias/parasitologia , Feminino , Fluorescência , Proteínas de Fluorescência Verde , Leishmania major/metabolismo , Leishmaniose Cutânea/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Fenotiazinas/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Reprodutibilidade dos Testes , Transfecção , Resultado do TratamentoRESUMO
Plasmodium falciparum uses multiple host receptors to attach and invade human erythrocytes. Glycophorins have been implicated as receptors for parasite invasion in human erythrocytes. Here, we screened a phage display cDNA library of P. falciparum (FCR3, a sialic acid-dependent strain) using purified glycophorins and erythrocytes as bait. Several phage clones were identified that bound to immobilized glycophorins and contained the same 74 bp insert encoding the 7-amino acids sequence ETTLKSF. A similar screen using intact human erythrocytes in solution identified additional phage clones containing the same 7-amino acids sequence. Using ELISA and immunofluorescence, direct binding of ETTLKSF peptide to glycophorins and erythrocytes was confirmed. Pull-down and protease treatment assays suggest that ETTLKSF peptide specifically interacts with glycophorin C. The synthetic ETTLKSF peptide partially blocks merozoite invasion in human erythrocytes. Further characterization of ETTLKSF peptide could lead to the development of a novel class of inhibitors against the blood stage malaria.
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Antimaláricos/farmacologia , Malária Falciparum/parasitologia , Oligopeptídeos/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/farmacologia , Sequência de Aminoácidos , Animais , Antimaláricos/química , Antimaláricos/isolamento & purificação , Células Cultivadas , Eritrócitos/parasitologia , Glicoforinas/química , Humanos , Malária Falciparum/sangue , Oligopeptídeos/química , Oligopeptídeos/genética , Oligopeptídeos/isolamento & purificação , Biblioteca de Peptídeos , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/isolamento & purificaçãoRESUMO
This article reviews recent developments in the design of polyvalent ligands for in vivo applications. Topics discussed include the design of polyvalent inhibitors of toxins and viruses, the use of polyvalency for targeted drug delivery and imaging, and applications of polyvalency for enhancing or suppressing immune responses.