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1.
Cell ; 168(6): 1041-1052.e18, 2017 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-28283060

RESUMO

Most secreted growth factors and cytokines are functionally pleiotropic because their receptors are expressed on diverse cell types. While important for normal mammalian physiology, pleiotropy limits the efficacy of cytokines and growth factors as therapeutics. Stem cell factor (SCF) is a growth factor that acts through the c-Kit receptor tyrosine kinase to elicit hematopoietic progenitor expansion but can be toxic when administered in vivo because it concurrently activates mast cells. We engineered a mechanism-based SCF partial agonist that impaired c-Kit dimerization, truncating downstream signaling amplitude. This SCF variant elicited biased activation of hematopoietic progenitors over mast cells in vitro and in vivo. Mouse models of SCF-mediated anaphylaxis, radioprotection, and hematopoietic expansion revealed that this SCF partial agonist retained therapeutic efficacy while exhibiting virtually no anaphylactic off-target effects. The approach of biasing cell activation by tuning signaling thresholds and outputs has applications to many dimeric receptor-ligand systems.


Assuntos
Anafilaxia/metabolismo , Células-Tronco Hematopoéticas/imunologia , Mastócitos/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais , Fator de Células-Tronco/metabolismo , Anafilaxia/imunologia , Animais , Dimerização , Humanos , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Engenharia de Proteínas , Proteínas Proto-Oncogênicas c-kit/agonistas , Proteínas Proto-Oncogênicas c-kit/química , Fator de Células-Tronco/química , Fator de Células-Tronco/genética
2.
Opt Lett ; 49(10): 2713-2716, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38748143

RESUMO

This Letter introduces a novel, to the best of our knowledge, method for achieving mode-locking and synchronization of mode-locked output pulses from two lasers. The proposed technique leverages parametric gain from difference frequency generation. Specifically, a Nd:YAG laser is mode-locked by single-pass mode-locked pulses from a mode-locked Ti:sapphire laser using an intracavity nonlinear crystal. When the continuous-wave laser is not actively pumped, the system functions as a synchronously pumped optical parametric oscillator. This novel approach has the potential to enable new devices, especially for pump-probe applications or for generation of mode-locked pulses in spectral regions where conventional mode-locked devices are typically not available.

3.
Langmuir ; 40(1): 100-108, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38109722

RESUMO

This study quantifies the influence of electrolytes on the kinetics of the spontaneous emulsification phenomenon (SEP) of heavy hydrocarbons in a nonionic surfactant solution. The rate of emulsifying hexadecane in Triton X-100, with the presence of sodium chloride and potassium chloride, has been measured using a technique of monitoring single oil droplet photography. The emulsion droplet size produced in the process was measured under the same conditions by using dynamic light scattering. The data obtained from the two experiments were employed to investigate the mass transfer coefficient of the surfactant molecules through the intermediate layer formed between hexadecane and the surfactant solution. It was found that the electrolytes in an aqueous solution increase the surfactant diffusion rate through the intermediate layer and reduce the emulsion droplet size. As a result, both electrolytes reduce the rate of spontaneous emulsification, with potassium chloride having a more substantial reduction. A model was developed to quantify the influence of electrolytes on the kinetics of the SEP. The data and modeling results verify the influence of ions on the kinetics of spontaneous emulsification. The results provide a significant foundation for predicting the solubilization of heavy hydrocarbons in an electrolyte solution.

4.
BMC Public Health ; 23(1): 624, 2023 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-37004009

RESUMO

Public health insurance (PHI) has been implemented with different levels of participation in many countries, from voluntary to mandatory. In Vietnam, a law amendment made PHI compulsory nationwide in 2015 with a tolerance phase allowing people a flexible time to enroll. This study aims to examine mechanisms under which the amendment affected the enrollment, healthcare utilization, and out-of-pocket (OOP) expenditures by middle- and low-income households in this transitioning process.Using the biennial Vietnam Household Living Standard Surveys, the study applied the doubly robust difference-in-differences approach to compare outcomes in the post-amendment period from the 2016 survey with those in the pre-amendment period from the 2014 survey. The approach inheriting advantages from its predecessors, i.e., the difference-in-differences and the augmented inverse-probability weighting methods, can mitigate possible biases in policy evaluations due to the changes within the group and between groups over time in the cross-section observational study.The results showed health insurance expansion with extensive subsidies in premiums and medical coverage for persons other than the full-time employed, young children or elderly members in the family, significantly increased enrollments in the middle- and low-income groups by 9% and 8%, respectively. The number of visits for PHI-eligible services also increased, approximately 0.5 more visit per person in the middle-income and 1 more visit per person in the low-income. The amendment, however, so far did not show any significant effect on reducing OOP payments, neither for the low nor the middle-income groups. To further expand PHI coverage and financial protections, policymakers should focus on improving public health facilities, contracting PHI to more accredited private health providers, and motivating the high-income group's enrollments.


Assuntos
Seguro Saúde , Pobreza , Criança , Humanos , Pré-Escolar , Idoso , Vietnã , Características da Família , Aceitação pelo Paciente de Cuidados de Saúde , Gastos em Saúde
5.
Molecules ; 28(9)2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37175380

RESUMO

Solvent extraction has been ubiquitously used to recover valuable metals from wastes such as spent batteries and electrical boards. With increasing demands for energy transition, there is a critical need to improve the recycling rate of critical metals, including copper. Therefore, the sustainability of reagents is critical for the overall sustainability of the process. Yet, the recycling process relies on functional organic compounds based on the hydroxyoxime group. To date, hydroxyoxime extractants have been produced from petrol-based chemical feedstocks. Recently, natural-based cardanol has been used to produce an alternative hydroxyoxime. The natural-based oxime has been employed to recover valuable metals (Ga, Ni, Co) via a liquid/liquid extraction process. The natural compound has a distinctive structure with 15 carbons in the alkyl tail. In contrast, petrol-based hydroxyoximes have only 12 or fewer carbons. However, the molecular advantages of this natural-based compound over the current petrol-based ones remain unclear. In this study, molecular dynamics simulation was employed to investigate the effect of extractant hydrocarbon chains on the extraction of copper ions. Two hydroxyoxime extractants with 12 and 15 carbons in the alkyl chain were found to have similar interactions with Cu2+ ions. Yet, a slight molecular binding increase was observed when the carbon chain was increased. In addition, lengthening the carbon chain made the extracting stage easier and the stripping stage harder. The binding would result in a lower pH in the extraction step and a lower pH in the stripping step. The insights from this molecular study would help design the extraction circuit using natural-based hydroxyoxime extractants. A successful application of cashew-based cardanol will improve the environmental benefits of the recycling process. With cashew-producing regions in developing countries, the application also improves these regions' social and economic sustainability.

6.
Molecules ; 28(22)2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-38005345

RESUMO

Thickener, also known as a gelling agent, is a critical component of lubricating greases. The most critical property of thickener, temperature resistance, is determined by the molecular structure of the compounds. Currently, all high-temperature-resistant thickeners are based on 12-hydroxystearic acid, which is exclusively produced from castor oil. Since castor oil is also an important reagent for other processes, finding a sustainable alternative to 12-hydroxystearic acid has significant economic implications. This study synthesises an alternative thickener from abundant agricultural waste, cashew nut shell liquor (CNSL). The synthesis and separation procedure contains three steps: (i) forming and separating calcium anacardate by precipitation, (ii) forming and separating anacardic acid (iii) forming lithium anacardate. The obtained lithium anacardate can be used as a thickener for lubricating grease. It was found that the recovery of anacardic acid was around 80%. The optimal reaction temperature and time conditions for lithium anacardate were 100 °C and 1 h, respectively. The method provides an economical alternative to castor and other vegetable oils. The procedure presents a simple pathway to produce the precursor for the lubricating grease from agricultural waste. The first reaction step can be combined with the existing distillation of cashew nut shell processing. An effective application can promote CNSL to a sustainable feedstock for green chemistry. The process can also be combined with recycled lithium from the spent batteries to improve the sustainability of the battery industry.

7.
Platelets ; 32(4): 440-443, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32552252

RESUMO

The study of extracellular vesicles (EVs) in plasma requires removal of cells including platelets. At present, a two-step centrifugation protocol is recommended and commonly used. A simpler protocol that is less operator dependent is likely to improve the quality of plasma samples collected for EV research. The objective of this study is to develop an easy, fast and clinically applicable centrifugation protocol to produce essentially platelet-free plasma with a high yield for EV research. We compared the two-step centrifugation protocol to a single-step protocol at 5,000 g for 20 minutes. The removal of platelets was computationally predicted and experimentally validated. Flow cytometry was used to detect residual platelets and platelet-derived (CD61+) EVs. The single-step protocol at 5,000 g (i) is less laborious and approximately ten minutes faster, (ii) removes platelets as effective as the two-step centrifugation protocol, and (iii) has a ~ 10% higher plasma yield, whereas (iv) the recovery of platelet-derived EVs is comparable. For future research on plasma EVs we recommend the newly developed, easy and fast single-step protocol for preparation of platelet-free plasma for research on plasma biomarkers including EVs.


Assuntos
Plaquetas/metabolismo , Centrifugação/métodos , Vesículas Extracelulares/metabolismo , Humanos
8.
Trop Med Int Health ; 25(11): 1362-1372, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32750213

RESUMO

OBJECTIVES: From 2005 to 2017, the prevalence of mortality in Vietnamese children under five years old showed large regional disparities. In 2017, mortality in the wealthiest region was 12.6‰, whereas the most disadvantaged region it was three times as high, at 36‰. This study aims to identify factors affecting regional disparities of the under-five mortality rate (U5MR) in Vietnam. METHODS: We applied Structural Equation Modelling to estimate the degree and the pathway through which undernutrition and socio-economic status (SES) contributed to the under-five mortality disparities. RESULTS: SES is estimated as a common latent factor of three socio-economic measures, that is, education, poverty and income. The direct effect of SES on U5MR is at 2.16 through the underweight pathway, which is 5 times higher than the effect of underweight on U5MR. Through the stunting channel, this direct impact is 1.43, nearly twice as high as the impact of the stunting rate. SES also has an indirect effect on U5MR through these undernutrition pathways. In total, we estimate that an increase in SES index will make the U5MR increase by 2.73‰. Among the three indicators of SES, poverty conveys the strongest signal of a considerable change in SES, thus to a subsequent change in U5MR. Among two types of undernutrition, the effect of stunting on U5MR is dominant, more than 3 times as high as that of underweight. CONCLUSION: These findings have important implications for socio-economic and health interventions: those that strongly focus on the reduction of regional poverty and stunting rates would be effective in bridging the regional gap in the U5MR in Vietnam.


OBJECTIFS: De 2005 à 2017, la prévalence de la mortalité chez les enfants vietnamiens de moins de cinq ans a montré de grandes disparités régionales. En 2017, la mortalité dans la région la plus riche était de 12,6 ‰, alors que dans la région la plus défavorisée elle était trois fois plus élevée, à 36 ‰. Cette étude vise à identifier les facteurs affectant les disparités régionales du taux de mortalité des moins de cinq ans (U5MR) au Vietnam. MÉTHODES: Nous avons appliqué la modélisation par équations structurelles pour estimer le degré et la voie par lesquels la sous-nutrition et le statut socioéconomique (SSE) contribuaient aux disparités de mortalité des moins de cinq ans. RÉSULTATS: Le SSE est estimé comme un facteur latent commun à trois mesures socioéconomiques, à savoir l'éducation, la pauvreté et le revenu. L'effet direct du SSE sur l'U5MR est de 2,16 dans la voie de l'insuffisance pondérale, ce qui est 5 fois plus élevé que l'effet de l'insuffisance pondérale sur l'U5MR. A travers la voie du retard de croissance, cet impact direct est de 1,43, soit près de deux fois plus élevé que l'impact du taux de retard de croissance. Le SSE a également un effet indirect sur l'U5MR à travers ces voies de sous-nutrition. Au total, nous estimons qu'une augmentation de l'indice de SSE fera augmenter l'U5MR de 2,73 ‰. Parmi les trois indicateurs du SSE, la pauvreté est le signal le plus fort d'un changement considérable du SSE, donc d'un changement ultérieur de l'U5MR. Parmi deux types de sous-nutrition, l'effet du retard de croissance sur l'U5MR est dominant, plus de 3 fois plus élevé que celui de l'insuffisance pondérale. CONCLUSION: Ces résultats ont des implications importantes pour les interventions socioéconomiques et de santé: celles qui se concentrent fortement sur la réduction de la pauvreté régionale et des taux de retard de croissance seraient efficaces pour combler l'écart régional dans l'U5MR au Vietnam.


Assuntos
Mortalidade da Criança/tendências , Desnutrição/epidemiologia , Classe Social , Pré-Escolar , Escolaridade , Feminino , Transtornos do Crescimento/epidemiologia , Humanos , Lactente , Recém-Nascido , Masculino , Estado Nutricional , Pobreza , Áreas de Pobreza , Prevalência , Fatores de Risco , Magreza/epidemiologia , Vietnã/epidemiologia
9.
Nephrol Dial Transplant ; 35(8): 1320-1327, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30590723

RESUMO

BACKGROUND: Ischaemia-reperfusion (IR) injury is an important determinant of delayed graft function (DGF) affecting allograft function. Mitochondrial DNA (mtDNA) is released upon cell death and platelet activation into the extracellular environment and has been suggested to be a biomarker in several diseases. Whether extracellular mtDNA accumulates in plasma and/or urine upon renal IR and predisposes DGF is unknown. METHODS: C57BL/6J wild-type mice were subjected to renal IR. In addition, an observational case-control study was set up enrolling 43 patients who underwent kidney transplantation. One day post-IR in mice and a few days following renal transplantation in human, blood and urine were collected. Patients were stratified into DGF and non-DGF groups. RESULTS: mtDNA-encoded genes accumulate in urine and plasma in both mice subjected to renal IR injury and in humans following renal transplantation. In human renal transplant recipients, cold ischaemia time and renal function correlate with urinary mtDNA levels. Urinary mtDNA levels but not urinary nuclear DNA levels were significantly higher in the DGF group compared with the non-DGF group. Multiple receiver operating characteristic curves revealed significant diagnostic performance for mtDNA-encoded genes cytochrome c oxidase III (COXIII); nicotinamide adenine dinucleotide hydrogen subunit 1 (NADH-deh); mitochondrially encoded, mitochondrially encoded nicotinamide adenine dinucleotide dehydrogenase 2 (MT-ND2) with an area under the curve of, respectively, 0.71 [P = 0.03; 95% confidence interval (CI) 0.54-0.89], 0.75 (P = 0.01; 95% CI 0.58-0.91) and 0.74 (P = 0.02; 95% CI 0.58-0.89). CONCLUSIONS: These data suggest that renal ischaemia time determines the level of mtDNA accumulation in urine, which associates with renal allograft function and the diagnosis of DGF following renal transplantation.


Assuntos
Biomarcadores/urina , DNA Mitocondrial/urina , Função Retardada do Enxerto/diagnóstico , Transplante de Rim/efeitos adversos , Traumatismo por Reperfusão/complicações , Animais , Estudos de Casos e Controles , Função Retardada do Enxerto/etiologia , Função Retardada do Enxerto/urina , Feminino , Sobrevivência de Enxerto , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Curva ROC , Transplantados , Transplante Homólogo
10.
J Chem Phys ; 152(2): 024709, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31941300

RESUMO

A novel method of measuring the core level binding energies of multiple sized nanoparticles on the same substrate is demonstrated using the early stage of Au nanoparticle growth on reduced r-TiO2(110). This method employed in situ scanning tunneling microscopy (STM) and microfocused X-ray photoemission spectroscopy. An STM tip-shadowing method was used to synthesize patterned areas of Au nanoparticles on the substrate with different coverages and sizes. Patterns were identified and imaged using a UV photoelectron emission microscope. The Au 4f core level binding energies of the nanoparticles were investigated as a function of Au nanoparticle coverage and size. A combination of initial and final state effects modifies the binding energies of the Au 4f core levels as the nanoparticle size changes. When single Au atoms and Au3 clusters are present, the Au 4f7/2 binding energy, 84.42 eV, is similar to that observed at a high coverage (1.8 monolayer equivalent), resulting from a cancellation of initial and final state effects. As the coverage is increased, there is a decrease in binding energy, which then increases at a higher coverage to 84.39 eV. These results are consistent with a Volmer-Weber nucleation-growth model of Au nanoparticles at oxygen vacancies, resulting in electron transfer to the nanoparticles.

11.
Proc Natl Acad Sci U S A ; 113(19): E2646-54, 2016 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-27091975

RESUMO

Therapeutic antitumor antibodies treat cancer by mobilizing both innate and adaptive immunity. CD47 is an antiphagocytic ligand exploited by tumor cells to blunt antibody effector functions by transmitting an inhibitory signal through its receptor signal regulatory protein alpha (SIRPα). Interference with the CD47-SIRPα interaction synergizes with tumor-specific monoclonal antibodies to eliminate human tumor xenografts by enhancing macrophage-mediated antibody-dependent cellular phagocytosis (ADCP), but synergy between CD47 blockade and ADCP has yet to be demonstrated in immunocompetent hosts. Here, we show that CD47 blockade alone or in combination with a tumor-specific antibody fails to generate antitumor immunity against syngeneic B16F10 tumors in mice. Durable tumor immunity required programmed death-ligand 1 (PD-L1) blockade in combination with an antitumor antibody, with incorporation of CD47 antagonism substantially improving response rates. Our results highlight an underappreciated contribution of the adaptive immune system to anti-CD47 adjuvant therapy and suggest that targeting both innate and adaptive immune checkpoints can potentiate the vaccinal effect of antitumor antibody therapy.


Assuntos
Anticorpos Monoclonais Murinos/administração & dosagem , Antígeno CD47/efeitos dos fármacos , Antígeno CD47/imunologia , Vacinas Anticâncer/administração & dosagem , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/terapia , Imunidade Adaptativa/efeitos dos fármacos , Imunidade Adaptativa/imunologia , Animais , Anticorpos Monoclonais Murinos/imunologia , Antineoplásicos/administração & dosagem , Antineoplásicos/imunologia , Vacinas Anticâncer/imunologia , Feminino , Imunização/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Terapia de Alvo Molecular/métodos , Neoplasias Experimentais/patologia , Resultado do Tratamento
12.
Allergol Immunopathol (Madr) ; 47(2): 179-184, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30292447

RESUMO

INTRODUCTION: Asthma is a chronic inflammatory, heterogeneous airway disease affecting millions of people around the world. Dendritic cells (DCs) are considered the most important antigen-presenting cell in asthma airway inflammatory reaction. But whether osteoprotegerin (OPG) mediate RANK/RANKL signaling inhibition influences asthma development by affecting the survival and function of DCs remains unclear. In this study, we assessed the effects of OPG on DCs and asthma. MATERIAL AND METHODS: BALB/c mice immunized with ovalbumin (OVA) were challenged thrice with an aerosol of OVA every second day for eight days. Dexamethasone (1.0mg/kg) or OPG (50µg/kg) was administered intraperitoneally to OVA-immunized BALB/c mice on day 24 once a day for nine days. Mice were analyzed for effects of OPG on asthma, inflammatory cell infiltration and cytokine levels in lung tissue. The expression of RANK and ß-actin was detected by Western Blot. DCs were isolated from mouse bone morrow. Cell survival was assessed by cell counting. The content of IL-12 was detected by ELISA. RESULTS: Results showed that OVA increased the number of inflammatory factors in BALF, elevated lung inflammation scores in mice. OPG reversed the alterations induced by OVA in the asthmatic mice. OPG inhibited the survival and function of DC via inhibition of RANK/RANKL signaling. CONCLUSIONS: This research proved inhibition of RANK/RANKL signaling by OPG could ease the inflammatory reaction in asthma, providing new evidence for the application of OPG on asthma.


Assuntos
Asma/metabolismo , Células Dendríticas/fisiologia , Osteoprotegerina/metabolismo , Pneumonia/metabolismo , Animais , Apresentação de Antígeno , Asma/imunologia , Sobrevivência Celular , Citocinas/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Pneumonia/imunologia , Ligante RANK/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Transdução de Sinais
13.
Clin Chem ; 64(4): 680-689, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29453194

RESUMO

BACKGROUND: Extracellular vesicles (EVs) in biofluids are potential biomarkers of disease. To explore the clinical relevance of EVs, a specific generic EV marker would be useful, one that does not require antibodies and binds to all EVs. Here we evaluated 5 commonly used generic markers for flow cytometry. METHODS: Flow cytometry (A60-Micro, Apogee) was used to evaluate the ability of the generic EV markers calcein acetoxymethyl ester, calcein acetoxymethyl ester violet, carboxyfluorescein succinimidyl ester (CFSE), 4-(2-[6-(dioctylamino)-2-naphthalenyl]ethenyl)-1-(3-sulfopropyl)pyridinium (di-8-ANEPPS), and lactadherin to stain EVs from MCF7 human breast adenocarcinoma cell line-conditioned culture medium [epithelial cell adhesion molecule positive (EpCAM+)] or platelet EVs from human plasma [integrin ß3 positive (CD61+)]. Side scatter triggering was applied as a reference, and the influence of non-EV components (proteins and lipoproteins) was evaluated. RESULTS: Di-8-ANEPPS, lactadherin, and side scatter detected 100% of EpCAM+ MCF7 EVs. Lactadherin and side scatter detected 33% and 61% of CD61+ EVs, respectively. Di-8-ANEPPS detected platelet EVs only if soluble protein was first removed. Because all generic markers stained proteins, at best 33% of platelet EVs in plasma were detected. The calcein markers and CFSE were either insensitive to EVs in both samples or associated with swarm detection. CONCLUSIONS: None of the generic markers detected all and only EVs in plasma. Side scatter triggering detected the highest concentration of plasma EVs on our A60-Micro, followed by lactadherin. The choice between scatter or lactadherin primarily depends on the analytical sensitivity of the flow cytometer used.


Assuntos
Vesículas Extracelulares/metabolismo , Citometria de Fluxo/métodos , Corantes Fluorescentes/química , Biomarcadores/metabolismo , Linhagem Celular , Humanos
14.
Microsc Microanal ; 29(Supplement_1): 743-744, 2023 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-37613452
16.
J Phys Chem A ; 121(17): 3213-3219, 2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28398756

RESUMO

Aqueous-based synthesis is one of the most popular methods to prepare nanoparticles. In these procedures, surfactants are needed to regulate the growth and final particle size. While there are numerous evidence on the decisive role of surfactants, a quantitative description remains elusive. This study develops a theoretical model to correlate the surfactant activities to particle growth. In the model, the "penetrability" of ions within surfactant layer is used to combine surface reaction and adsorption/desorption processes. The penetrability was then directly correlated to surfactant size. The theory was verified by synthesis of iron oxide nanoparticles with series of cationic surfactants. Eight surfactants, with same headgroup and increasing hydrocarbon tail, were employed. The experimental data showed a deterministic correlation between surfactant tails and particle size. The experimental correlation between surfactant length and particle size was predicted by the model. The modeling results verify the role of surfactant as capping agent during particle growth. More importantly, it provides a theoretical framework to control particle size in wet synthesis.

17.
Med Vet Entomol ; 31(1): 72-77, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27859488

RESUMO

Engorged female Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) were collected from dogs in the state of Yucatán, Mexico. Fourteen tick populations were collected from dogs at seven veterinary clinics, four residential homes and three cattle farms. The larval immersion test was used in the progeny of collected adult females to test susceptibility to amitraz and cypermethrin. Dose-mortality regressions, 50% lethal concentrations (LC50 ), confidence intervals and slope were estimated by probit analysis. For amitraz, 12 tick populations (85.7%) were classified as resistant and low inter-population variation in the phenotypic level of resistance was evident [resistance ratios (RRs) at LC50 : 1.0-13.0]. For cypermethrin, 12 tick populations (85.7%) were classified as resistant and substantial inter-population variation in the phenotypic level of resistance was evident (RRs at LC50 : 1.0-104.0). Thus, amitraz resistance in R. sanguineus s.l. is common, but generally occurs at low levels; however, alarmingly high levels of cypermethrin resistance are present in R. sanguineus s.l. populations in dogs in Yucatán, Mexico. The intensive use of both acaricides to control ectoparasites on dogs is likely to lead to more serious resistance problems that may cause high levels of control failure in the future.


Assuntos
Acaricidas/farmacologia , Piretrinas/farmacologia , Rhipicephalus sanguineus/efeitos dos fármacos , Infestações por Carrapato/veterinária , Toluidinas/farmacologia , Animais , Doenças do Cão/parasitologia , Cães , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Feminino , Dose Letal Mediana , México , Infestações por Carrapato/parasitologia
18.
J Biol Chem ; 290(20): 12650-63, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25837251

RESUMO

CD47 is a cell surface protein that transmits an anti-phagocytic signal, known as the "don't-eat-me" signal, to macrophages upon engaging its receptor signal regulatory protein α (SIRPα). Molecules that antagonize the CD47-SIRPα interaction by binding to CD47, such as anti-CD47 antibodies and the engineered SIRPα variant CV1, have been shown to facilitate macrophage-mediated anti-tumor responses. However, these strategies targeting CD47 are handicapped by large antigen sinks in vivo and indiscriminate cell binding due to ubiquitous expression of CD47. These factors reduce bioavailability and increase the risk of toxicity. Here, we present an alternative strategy to antagonize the CD47-SIRPα pathway by engineering high affinity CD47 variants that target SIRPα, which has restricted tissue expression. CD47 proved to be refractive to conventional affinity maturation techniques targeting its binding interface with SIRPα. Therefore, we developed a novel engineering approach, whereby we augmented the existing contact interface via N-terminal peptide extension, coined "Velcro" engineering. The high affinity variant (Velcro-CD47) bound to the two most prominent human SIRPα alleles with greatly increased affinity relative to wild-type CD47 and potently antagonized CD47 binding to SIRPα on human macrophages. Velcro-CD47 synergizes with tumor-specific monoclonal antibodies to enhance macrophage phagocytosis of tumor cells in vitro, with similar potency as CV1. Finally, Velcro-CD47 interacts specifically with a subset of myeloid-derived cells in human blood, whereas CV1 binds all myeloid, lymphoid, and erythroid populations interrogated. This is consistent with the restricted expression of SIRPα compared with CD47. Herein, we have demonstrated that "Velcro" engineering is a powerful protein-engineering tool with potential applications to other systems and that Velcro-CD47 could be an alternative adjuvant to CD47-targeting agents for cancer immunotherapy.


Assuntos
Antineoplásicos , Antígeno CD47 , Macrófagos/metabolismo , Neoplasias/tratamento farmacológico , Fagocitose/efeitos dos fármacos , Receptores Imunológicos/antagonistas & inibidores , Animais , Anticorpos , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Antígeno CD47/química , Antígeno CD47/genética , Antígeno CD47/farmacologia , Linhagem Celular Tumoral , Humanos , Imunoterapia , Macrófagos/patologia , Camundongos , Neoplasias/genética , Neoplasias/metabolismo , Ligação Proteica , Engenharia de Proteínas , Estrutura Terciária de Proteína , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo
19.
Langmuir ; 32(48): 12842-12847, 2016 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-27934519

RESUMO

The ionic state of an adsorbed gemini surfactant at the air/water interface was investigated using a combination of surface potential and surface tension data. The combined model was developed and successfully described the experimental data. The results verified the existence of three ionic states of the gemini surfactant in the interfacial zone. Furthermore, the model can quantify the adsorbed concentrations of these species. At low concentrations, the fully dissociated state dominates the adsorption. At high concentrations, the fully associated state dominates, accounting for up to 80% of the total adsorption. In the middle range, the adsorption is dominated by the partially associated state, which has a maximum percentage of 80% at a critical micelle concentration of 0.5. The variation in the ionic state is a unique characteristic of gemini surfactants, which can be the underlying mechanism for their advantages over conventional surfactants.

20.
Lupus ; 25(1): 88-92, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26306741

RESUMO

Ocular involvement sometimes occurs with systemic lupus erythematosus (SLE) but enophthalmos with SLE is rare. We report a case of enophthalmos with SLE. A 25-year-old male was admitted for two weeks of fever, sore throat, arthralgia, chest pain and right arm weakness with pain. We diagnosed him with SLE with malar rash, arthritis, pleural effusion, proteinuria, leukopenia, positive antinuclear antibody, anti-dsDNA, and lupus anticoagulant. The patient was prescribed high-dose prednisolone and hydroxychloroquine 400 mg. One week after discharge, he complained about a sensation of a sunken right eye. CT showed right enophthalmos, a post-inflammatory change and chronic inflammation. Proteinuria increased to 3.8 g/day after the patient stopped taking prednisolone. Cyclophosphamide therapy was administered for three months without improvement. We decided to restart prednisolone and change cyclophosphamide to mycophenolate mofetil. Proteinuria decreased but enophthalmos remains as of this reporting.


Assuntos
Enoftalmia/etiologia , Lúpus Eritematoso Sistêmico/complicações , Adulto , Substituição de Medicamentos , Quimioterapia Combinada , Enoftalmia/diagnóstico , Humanos , Imunossupressores/administração & dosagem , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Masculino , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento
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