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1.
BMC Plant Biol ; 24(1): 472, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38811894

RESUMO

Salinity stress, an ever-present challenge in agriculture and environmental sciences, poses a formidable hurdle for plant growth and productivity in saline-prone regions worldwide. Therefore, this study aimed to explore the effectiveness of trehalose and mannitol induce salt resistance in wheat seedlings. Wheat grains of the commercial variety Sakha 94 were divided into three groups : a group that was pre-soaked in 10 mM trehalose, another group was soaked in 10 mM mannitol, and the last was soaked in distilled water for 1 hour, then the pre soaked grains cultivated in sandy soil, each treatment was divided into two groups, one of which was irrigated with 150 mM NaCl and the other was irrigated with tap water. The results showed that phenols content in wheat seedlings increased and flavonoids reduced due to salt stress. Trehalose and mannitol cause slight increase in total phenols content while total flavonoids were elevated highy in salt-stressed seedlings. Furthermore, Trehalose or mannitol reduced salt-induced lipid peroxidation. Salt stress increases antioxidant enzyme activities of guaiacol peroxidase (G-POX), ascorbate peroxidase (APX), and catalase (CAT) in wheat seedlings, while polyphenol oxidase (PPO) unchanged. Trehalose and mannitol treatments caused an increase in APX, and CAT activities, whereas G-POX not altered but PPO activity were decreased under salt stress conditions. Molecular docking confirmed the interaction of Trehalose or mannitol with peroxidase and ascorbic peroxidase enzymes. Phenyl alanine ammonia layase (PAL) activity was increased in salt-stressed seedlings. We can conclude that pre-soaking of wheat grains in 10 mM trehalose or mannitol improves salinity stress tolerance by enhancing antioxidant defense enzyme and/or phenol biosynthesis, with docking identifying interactions with G-POX, CAT, APX, and PPO.


Assuntos
Manitol , Tolerância ao Sal , Plântula , Trealose , Triticum , Triticum/efeitos dos fármacos , Triticum/fisiologia , Triticum/metabolismo , Trealose/metabolismo , Plântula/efeitos dos fármacos , Plântula/fisiologia , Manitol/farmacologia , Tolerância ao Sal/efeitos dos fármacos , Simulação de Acoplamento Molecular , Antioxidantes/metabolismo , Estresse Salino/efeitos dos fármacos , Flavonoides/metabolismo , Fenóis/metabolismo
2.
RSC Adv ; 14(8): 5566-5576, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38352687

RESUMO

An in situ synthesis approach is used to directly grow a microsphere of melamine-glutaraldehyde (MAGA) polymer over three-dimensional (3D) nickel foam (NF). The materials are used to produce nitrogen-doped carbon (NC) with and without NF. These precursors undergo carbonization at various temperatures, namely 400 °C, 500 °C, and 700 °C. The electrochemical properties of the materials would be significantly improved by directly growing MAGA polymer on the surface of NF. The electrochemical performance of NC/NF-400 was excellent, with a capacitance of 297 F g-1 achieved at a current density of 1 A g-1. The in situ growing approach does not necessitate the use of additional chemical agents, such as binders or conductive compounds when preparing the electrode. In addition, the material exhibits only 10% reduction in capacitance after undergoing 5000 cycles, indicating excellent cycling performance. The outstanding electrochemical performance achieved by using the in situ method of MAGA microsphere polymer on NF may be attributed to the rapid transit of ions to the electrode surfaces, facilitating effortless redox reactions.

3.
BMC Chem ; 17(1): 134, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37814299

RESUMO

RATIONALE: Antibiotics have been detected worldwide in the aquatic environment. Moreover, certain classes of antibiotics have been repurposed for the management of COVID-19, which increased their use and presence in wastewater. Their occurrence even in low concentrations leads to the development of antibiotic resistance. METHODOLOGY: Magnetite pectin nanoparticles (MPNP) were fabricated and compared to an established model of mesoporous silica nanoparticles (MSNP). Our studied adsorbate is levofloxacin, a fluoroquinolone antibiotic, commonly used in managing COVID-19 cases. RESULTS: The influence of various factors affecting the adsorption process was studied, such as pH, the type and concentration of the adsorbent, contact time, and drug concentration. The results illustrated that the optimum adsorption capacity for antibiotic clearance from wastewater using MPNP was at pH 4 with a contact time of 4 h; while using MSNP, it was found to be optimum at pH 7 with a contact time of 12 h at concentrations of 10 µg/mL and 16 g/L of the drug and nanoparticles, respectively, showing adsorption percentages of 96.55% and 98.89%. Drug adsorption equilibrium data obeyed the Sips isotherm model. DISCUSSION AND CONCLUSION: HPLC assay method was developed and validated. The experimental results revealed that the MPNP was as efficient as MSNP for removing the antibacterial agent. Moreover, MPNP is eco-friendly (a natural by-product of citrus fruit) and more economic as it could be recovered and reused. The procedure was evaluated according to the greenness assessment tools: AGREE calculator and Hexagon-CALIFICAMET, showing good green scores, ensuring the process's eco-friendliness.

4.
Drug Dev Ind Pharm ; 49(9): 580-589, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37725083

RESUMO

INTRODUCTION: Countless individuals experience negative emotions as hair loss pattern affects their self-esteem and well-being. Rosuvastatin calcium (Ca-RUV) was reported to stimulate the growth of the hair in the applied area, hence, it was selected as a potential hair loss treatment drug. SIGNIFICANCE: This study aims to develop and optimize (Ca-RUV) loaded squarticles (SQRs) and assess their ability to deliver and release Ca-RUV in the hair follicle for the promotion of hair growth. METHODS: A response surface design was utilized to study the effect of varying Pluronic® F68 (PF68) and the percentage of liquid lipids within the core of the SQRs and the effects of particle size, entrapment efficiency, and drug released percentage after 24 h (%Q24) were assessed. The optimized formula was subjected to DSC, XRD, and in-vivo evaluation in rats. RESULTS: SQRs stabilized by 0.8% PF68 and contained 37.5% liquid lipids showed an acceptable particle size (250 nm), drug entrapment efficiency (75%), and %Q24 (100%). The in-vivo studies illustrated the ability of the formula to regrow hair in animals after 10 days due to the elevation of the vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) to their normal values and by 9% and 54%, respectively, relative to standard therapy minoxidil (5%). CONCLUSION: Thus, it can be concluded that the optimized formula of Ca-RUV loaded SQRs showed superior in-vivo results in the promotion of hair growth in a shorter period relative to the marketed product. Therefore, the formula can offer a viable option for the treatment of hair loss.


Assuntos
Cabelo , Fator A de Crescimento do Endotélio Vascular , Animais , Ratos , Alopecia/tratamento farmacológico , Cabelo/crescimento & desenvolvimento , Lipídeos/farmacologia , Rosuvastatina Cálcica/farmacologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fatores de Crescimento do Endotélio Vascular/farmacologia , Fatores de Crescimento do Endotélio Vascular/uso terapêutico
5.
Pharm Dev Technol ; 28(8): 785-798, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37610935

RESUMO

Rheumatoid arthritis (RA) is a chronic autoimmune disease which affects around 1% globally leading to joint inflammation and disability. Etorocoxib (ETR) is a potent COX-2 inhibitor traditionally used orally to alleviate RA induced inflammation, yet it causes hepatic side effects on prolonged use. This study aims for in silico optimization of ETR polyelectrolyte complex (PEC) utilizing chondroitin sulphate (CS) and chitosan (CH) for transdermal delivery to RA-inflamed joints with a synergistic anti-inflammatory action owing to CS. An artificial neural network (ANN) combined with 22 factorial design was used to optimize the PEC formula according to particle size (PS) and entrapment efficiency (%EE) by varying CS and CH concentrations. The optimum ETR PEC was incorporated in a gel and examined for its in vitro release, ex vivo permeation, in vivo inflammatory biomarkers, and histopathological evaluation in rats. The optimized formula (F3) with 0.1 CH% w/w and 0.5 CS %w/w showed a PS of 214.98 ± 17.24 nm, %EE 75.31 ± 1.67%, and enhanced in vitro release profile, ex vivo permeation and in vivo anti-inflammatory effect compared to ETR gel via suppressing the expression of IL-6, TNF-α, and TGF-ß pro-inflammatory cytokines as well as the additional anti-inflammatory effect of CS. In conclusion, ETR-PEC gel holds promise as transdermal therapy for managing RA-induced inflammation.


Assuntos
Artrite Reumatoide , Quitosana , Ratos , Animais , Sulfatos de Condroitina , Polieletrólitos/uso terapêutico , Administração Cutânea , Artrite Reumatoide/tratamento farmacológico , Inflamação/tratamento farmacológico , Tamanho da Partícula
6.
Nurs Open ; 10(11): 7118-7129, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37632315

RESUMO

AIM: To assess the effect of parental and peer support on children's self-esteem during the isolation period in COVID-19-infected children is the main objective of this study. DESIGN: This is a descriptive cross-sectional study. One hundred ninety children with a confirmed diagnosis of COVID-19 were included. METHODS: A survey questionnaire to assess family and children's demographic characteristics was used for this study. A 13-item scale to assess parental support during the isolation period and a 10-item scale to assess peers' support during the isolation period were evaluated. Along with it, a 10-item scale to assess self-esteem during the isolation period was also measured. RESULTS: Home isolation was associated with higher parental and peer support scores than hospital isolation. The mean age of study participants was 13.23 ± 4.05 years; 52.6% were isolated at home versus 47.4% in hospital isolation. Phone calling and WhatsApp/messenger chat were methods of communication for 44.2% and 33.2% of patients, respectively. 6.3% of them had no method of communication. Child self-esteem was significantly affected by both parental and peer support during isolation. The increase in pronounced negative psychological effects such as disorientation, anger, low self-esteem and post-traumatic distress may be caused by a lack of parental care. NO PATIENT OR PUBLIC CONTRIBUTION TO THIS STUDY: Patients or the general public were not involved in the design, analysis or interpretation of the data in this study. The study's aim and objectives were developed based on children's self-esteem, which was limited by questionnaire data information, so the researchers completed demographic and disease-related questionnaires by interviewing them.


Assuntos
COVID-19 , Humanos , Criança , Adolescente , Estudos Transversais , Pais , Inquéritos e Questionários , Relações Pais-Filho
7.
Molecules ; 27(10)2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35630573

RESUMO

The house fly Musca domestica L. is one of the medical and veterinary pests that can develop resistance to different insecticides. Mixing insecticides is a new strategy for accelerating pest control; furthermore, it can overcome insect resistance to insecticides. This study aims to evaluate three insecticides, chlorfenapyr, abamectin, and lambda-cyhalothrin, individually and their binary mixtures against 2nd instar larvae of M. domestica laboratory strain. Chlorfenapyr exhibited the most toxic effect on larvae, followed by abamectin then the lambda-cyhalothrin. The half-lethal concentrations (LC50) values were 3.65, 30.6, and 94.89 ppm, respectively. These results revealed that the high potentiation effect was the mixture of abamectin/chlorfenapyr in all the mixing ratios. In contrast, the tested combination of lambda-cyhalothrin/abamectin showed an antagonism effect at all mixing ratios against house fly larvae. The total protein, esterases, glutathione-S-transferase (GST), and cytochrome P-450 activity were also measured in the current investigation in the larvae treated with chlorfenapyr. Our results indicate that GST may play a role in detoxifying chlorfenapyr in M. domestica larvae. The highest activity of glutathione-S-transferase was achieved in treated larvae with chlorfenapyr, and an increase in cytochrome P-450 activity in the larvae was observed post-treatment with Abamectin/chlorfenapyr.


Assuntos
Moscas Domésticas , Inseticidas , Animais , Sistema Enzimático do Citocromo P-450 , Glutationa , Resistência a Inseticidas , Inseticidas/farmacologia , Ivermectina/análogos & derivados , Larva , Nitrilas , Piretrinas , Transferases
8.
Antioxidants (Basel) ; 11(5)2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35624793

RESUMO

Foodborne infections and antibiotic resistance pose a serious threat to public health and must be addressed urgently. Pistacia lentiscus is a wild-growing shrub and has been utilized for medicinal applications as well as for culinary purposes. The antibacterial and antioxidant activities of P. lentiscus bark in vitro, as well as the phytochemical composition, are the focus of this inquiry. The bark extract of P. lentiscus showed significant antimicrobial activity in experiments on bacteria and yeast isolated from human and food sources. The exposure time for the complete inhibition of cell viability of P. aeruginosa in the extracts was found to be 5% at 15 min. Phytochemical inquiry of the methanol extract demonstrates the existence of carbohydrates, flavonoids, tannins, coumarins, triterpenes, and alkaloids. Deep phytochemical exploration led to the identification of methyl gallate, gallic acid, kaempferol, quercetin, kaempferol 3-O-α-rhamnoside, kaempferol 3-O-ß-glucoside, and Quercetin-3-O-ß-glucoside. When tested using the DPPH assay, the methanol extracts of P. lentiscus bark demonstrated a high free radical scavenging efficiency. Further, we have performed a molecular modelling study which revealed that the extract of P. lentiscus bark could be a beneficial source for novel flavonoid glycosides inhibitors against SARS-CoV-2 infection. Taken together, this study highlights the Pistacia lentiscus bark methanol extract as a promising antimicrobial and antiviral agent.

9.
Plants (Basel) ; 11(9)2022 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-35567152

RESUMO

The effect of melatonin (MT) on potato plants under drought stress is still unclear in the available literature. Here, we studied the effect of MT as a foliar application at 0, 0.05, 0.1, and 0.2 mM on potato plants grown under well-watered and drought stressed conditions during the most critical period of early tuberization stage. The results indicated that under drought stress conditions, exogenous MT significantly (p ≤ 0.05) improved shoot fresh weight, shoot dry weight, chlorophyll (Chl; a, b and a + b), leaf relative water content (RWC), free amino acids (FAA), non-reducing sugars, total soluble sugars, cell membrane stability index, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX) compared to the untreated plants. Meanwhile, carotenoids, proline, methylglyoxal (MG), H2O2, lipid peroxidation (malondialdehyde; MDA) and abscisic acid (ABA) were significantly decreased compared to the untreated plants. These responses may reveal the protective role of MT against drought induced carbonyl/oxidative stress and enhancing the antioxidative defense systems. Furthermore, tuber yield was differentially responded to MT treatments under well-watered and drought stressed conditions. Since, applied-MT led to an obvious decrease in tuber yield under well-watered conditions. In contrast, under drought conditions, tuber yield was substantially increased by MT-treatments up to 0.1 mM. These results may imply that under water deficiency, MT can regulate the tuberization process in potato plants by hindering ABA transport from the root to shoot system, on the one hand, and by increasing the non-reducing sugars on the other hand.

10.
Toxics ; 10(5)2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35622684

RESUMO

Lead (Pb) is a widespread and nondegradable environmental pollutant and affects several organs through oxidative mechanisms. This study was conducted to investigate the antioxidant protective effect of glycine betaine (GB) against Pb-induced renal and hepatic injury. Male albino rats (n = 45) were divided into three groups: G1 untreated control, G2 Pb-acetate (50 mg/kg/day), and G3 Pb-acetate (50 mg/kg/day) plus GB (250 mg/kg/day) administered for 6 weeks. For G3, Pb-acetate was administered first and followed by GB at least 4 h after. Pb-acetate treatment (G2) resulted in a significant decrease in renal function, including elevated creatinine and urea levels by 17.4% and 23.7%, respectively, and nonsignificant changes in serum uric acid levels. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphates (ALP) activities were significantly increased with Pb treatment by 37.6%, 59.3%, and 55.1%, respectively. Lipid peroxidation level was significantly increased by 7.8 times after 6 weeks of Pb-acetate treatment. The level of reduced glutathione (GSH-R) significantly declined after Pb-acetate treatment. Pb-acetate treatment also reduced the activities of superoxide dismutase (SOD), glutathione-S-transferase (GST), and glutathione peroxidase (GSH-PX) by 74.1%, 85.0%, and 40.8%, respectively. Treatment of Pb-intoxicated rats with GB resulted in a significant reduction in creatinine, urea, ALT, AST, and lipid peroxidation, as well as a significant increase in the level of GSH-R and in the activities of ALP, SOD, GST, and GSH-PX. The molecular interaction between GB and GSH-PX indicated that the activation of GSH-PX in Pb-intoxicated rats was not the result of GB binding to the catalytic site of GSH-PX. The affinity of GB to bind to the catalytic site of GSH-PX is lower than that of H2O2. Thus, GB significantly mitigates Pb-induced renal and liver injury through the activation of antioxidant enzymes and the prevention of Pb-induced oxidative damage in the kidney and liver.

11.
J Toxicol ; 2021: 9954443, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34422042

RESUMO

Nanoparticles are of great importance in development and research because of their application in industries and biomedicine. The development of nanoparticles requires proper knowledge of their fabrication, interaction, release, distribution, target, compatibility, and functions. This review presents a comprehensive update on nanoparticles' toxic effects, the factors underlying their toxicity, and the mechanisms by which toxicity is induced. Recent studies have found that nanoparticles may cause serious health effects when exposed to the body through ingestion, inhalation, and skin contact without caution. The extent to which toxicity is induced depends on some properties, including the nature and size of the nanoparticle, the surface area, shape, aspect ratio, surface coating, crystallinity, dissolution, and agglomeration. In all, the general mechanisms by which it causes toxicity lie on its capability to initiate the formation of reactive species, cytotoxicity, genotoxicity, and neurotoxicity, among others.

12.
Materials (Basel) ; 13(22)2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33207641

RESUMO

Gallium (Ga) doped zinc oxide (ZnO) nanocrystals were successfully synthesized via a γ-radiation-assisted polymer-pyrolysis route. Ga doped ZnO samples with Ga and ZnO precursor salts with molar ratios of 0%, 3%, 5%, and 10% were produced. A γ-radiation dosage of 1.5 kGy was used for polymerization initiation during the sample preparation. The properties of the obtained nanocrystal samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible absorption, NIR-VIS-UV diffused reflectance, and high-resolution transmission electron microscopy (HR-TEM) characterization techniques. XRD results revealed the formation of ZnO nanocrystals with wurtzite structure for both Ga-doped and undoped ZnO samples. Noticeable increasing in the line broadening of the XRD peaks as well as pronounced decreasing of crystallite size were observed with the increasing Ga ratio in the samples. Optical peaks around Ga:ZnO samples showed a blueshift in the optical absorption peaks with increasing Ga content. These results are in good agreement with the dependency of crystallites size as well as grain size on Ga ratio obtained from XRD and TEM images, which make them fit well for the powder cool-pigment applications. The doped samples showed high values of NIR reflectance (RNIR*) with percentage varied from 84.25% to 89.05% that enabled them to qualify for cool-nanopigment applications. Furthermore, such doped samples registered low values of visible reflectance (RVIS*) that enabled to reduce the glare from the reflected visible sunlight.

13.
J Colloid Interface Sci ; 552: 9-16, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31100690

RESUMO

HYPOTHESIS: Adsorption of hydrophobically modified ethoxylated urethane polymers (HEURs) at the soft colloid interfaces of emulsion droplets will stabilise oil-in-water emulsions (a) via steric stabilisation induced by adsorption of the polymer at the droplet surfaces through the hydrophobic groups, and (b) via continuous phase viscosity enhancement through polymer self-association. Both of these mechanisms will be modulated by the presence of the surfactant, sodium dodecylsulfate (SDS). EXPERIMENTS: Dodecane-in-water emulsions stabilised by three HEUR polymers with different structural composition were examined in the absence and presence of SDS by NMR spectroscopy and small-angle neutron scattering (SANS). The effect of adsorption of the polymer to the dodecane droplet surfaces, and the conformation of the self-associating polymer in the aqueous solution were quantified. FINDINGS: All emulsions were stable for days-weeks. Diffusion data showed the formation of oil droplets of hundreds of nm in size in the presence of all three HEURs, here denoted C6-L-(EO100-L)9-C6, C10-L-(EO200-L)4-C10, and C18-L-(EO200-L)7-C18, where EOx represents a block of ethylene oxide of x monomers, L denotes the linker group, and Cn the length of the hydrophobic end-group. No significant changes in droplet size across this series of polymers was observed. Collectively, the results point to adsorption of the polymer to the droplet surfaces, which results in a small decrease in the effective polymer solution concentration, thereby driving to significant changes in the structure and dynamics of the system. Evident in the SANS data in particular, is a subtle balance between the characteristic features reflecting polymer self-association, and those associated with polymer structures commensurate with a larger length-scale, dependent on the system composition. Surprisingly, the polymer and polymer/SDS complex in the presence of oil show slightly greater diffusive rates relative to the analogous systems in the absence of the oil. Finally, the partitioning of the three polymers in phase-separated samples was studied by 1H NMR, and it was shown that the C18-L-(EO200-L)7-C18 exhibited a greater partitioning in the oil phase compared with C6-L-(EO100-L)9-C6 and C10-L-(EO200-L)4-C10, an observation that may be understood in terms of the structural composition of the HEURs. The SDS showed a positive correlation between its partitioning in the two layers with the polymer partitioning, evidence of a strong interaction between the surfactant and the polymer, consistent with the behaviour observed in the oil-free system.

14.
J Colloid Interface Sci ; 539: 126-134, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30579216

RESUMO

HYPOTHESIS: The presence of surfactant modulates the surface-chemistry-specific interaction of hard colloidal particles (latex) with HEUR polymers, principally through introducing a preferential solution interaction rather than a competitive surface interaction; addition of surfactant leads to a preponderance of polymer/surfactant solution complexes rather than surface-bound complexes. EXPERIMENTS: A range of model formulations comprising a hexyl end-capped urethane polymer (C6-L-(EO100-L)9-C6), sodium dodecylsulfate (SDS) and a series of polystyrene-butylacrylate latices (PS-BA-L) have been characterised in terms of rheology, particle surface area (solvent relaxation NMR), polymer conformation (small-angle neutron scattering) and solution composition to build up a detailed picture of the distribution of the HEUR in the presence of both surfactant and latex. FINDINGS: There is very weak adsorption of C6-L-(EO100-L)9-C6 to only the most hydrophobic latex surface studied, an adsorption that is further weakened by the addition of low levels of surfactant. Macroscopic changes in the hydrophobic latex system may be interpreted in terms of bridging flocculation at low polymer concentrations. No adsorption of C6-L-(EO100-L)9-C6 is observed in the case of hydrophilic surfaces. In most cases, the observed behaviour of the ternary system (polymer/surfactant/particle) is highly reminiscent of the binary (polymer/surfactant) system at the appropriate composition, suggesting that the polymer/surfactant solution interaction is the dominant one.

15.
J Colloid Interface Sci ; 529: 588-598, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30031286

RESUMO

HYPOTHESIS: Hydrophobically modified ethoxylated urethane polymers (HEURs) are widely used to control the rheological profile of formulated particulate dispersions through associative network formation, the properties of which are perturbed by the presence of surfactants. At high polymer concentrations and in the presence of surfactants, it is hypothesised that the dominant factors in determining the rheological profile are the number and composition of the mixed hydrophobic aggregates, these being defined by the number and distribution of the hydrophobic linkers along the polymer backbone, rather than the end-group hydrophobe characteristics per se that dominate the low polymer concentration behaviour. EXPERIMENTS: Three different HEUR polymers with formulae (C6-L-(EO100-L)9-C6, C10-L-(EO200-L)4-C10 and C18-L-(EO200-L)7-C18 (where L = urethane linker, Cn = hydrophobic end-group chain length, and EO = ethylene oxide block) have been studied in the absence and presence of SDS employing techniques that quantify (a) the bulk characteristics of the polymer surfactant blend, (b) the structure and composition of the hydrophobic domains, (c) the dynamics of the polymer and surfactant, and (d) the polymer conformation. Collectively, these experiments demonstrate how molecular-level interactions between the HEURs and sodium dodecylsulfate (SDS) define the macroscopic behaviour of the polymer/surfactant mixture. FINDINGS: Binding of the SDS to the polymer via two mechanisms - monomeric anti-cooperative and micellar cooperative - leads to surfactant-concentration-specific macroscopic changes in the viscosity. Binding of the surfactant to the polymer drives a conformational rearrangement, and an associated redistribution of the polymer end-groups and linker associations throughout the hydrophobic domains. The composition and size of these domains are sensitive to the polymer architecture. Therefore, there is a complex balance between polymer molecular weight, ethylene oxide block size, and number of urethane linkers, coupled with the size of the hydrophobic end-groups. In particular, the urethane linkers are shown to play a hitherto largely neglected but important role in driving the polymer association.

16.
Eur J Pharm Biopharm ; 97(Pt A): 218-22, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25986588

RESUMO

Drug delivery via the eye, nose, gastrointestinal tract and lung is of great interest as they represent patient-compliant and facile methods to administer drugs. However, for a drug to reach the systemic circulation it must penetrate the "mucus barrier". An understanding of the characteristics of the mucus barrier is therefore important in the design of mucus penetrating drug delivery vehicles e.g. nanoparticles. Here, a range of nanoparticles - silica, aluminium coated silica, poly (lactic-co-glycolic acid) (PLGA) and PEGylated PLGA - each with known but different physicochemical characteristics were examined in the presence of mucin to identify those characteristics that engender nanoparticle/mucin interactions and thus, to define "design rules" for mucus penetrating (nano)particles (MPP), at least in terms of the surface characteristics of charge and hydrophilicity. Dynamic light scattering (DLS) and rheology have been used to assess the interaction between such nanoparticles and mucin. It was found that negatively charged and hydrophilic nanoparticles do not exhibit an interaction with mucin whereas positively charged and hydrophobic nanoparticles show a strong interaction. Surface grafted poly (ethylene glycol) (PEG) chains significantly reduced this interaction. This study clearly demonstrates that the established colloid science techniques of DLS and rheology are very powerful screening tools to probe nanoparticle/mucin interactions.


Assuntos
Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Mucinas/metabolismo , Nanopartículas , Animais , Difusão Dinâmica da Luz , Interações Hidrofóbicas e Hidrofílicas , Muco/metabolismo , Polietilenoglicóis/química , Reologia , Suínos
17.
Transl Res ; 158(3): 155-62, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21867981

RESUMO

The prospect of the growing worldwide epidemic of hepatitis C virus (HCV) infection and type 2 diabetes mellitus certainly merits attention toward their controversial relationship. Insulin-like growth factor-1 (IGF-1) plays an important role in glucose homeostasis. This study is a cross-sectional study considered as an initial investigation aimed to evaluate the effect of HCV infection on serum IGF-1, as well as to find out whether IGF-1 has a role in development of insulin resistance (IR) in HCV infection. A total of 45 subjects divided into 3 groups were included in the study: chronic HCV-infected patients (15 patients), chronic HCV-infected diabetic patients (15 patients), and diabetic patients without HCV infection (15 patients), along with 15 healthy controls. HCV RNA was quantified using real-time polymerase chain reaction (PCR). Serum IGF-1 levels were measured by enzyme-linked immunosorbent assay (ELISA). Homeostasis model assessment of insulin resistance [HOMA-IR], insulin sensitivity [HOMA-S], and ß-cell function [HOMA-ß] were determined by previously validated mathematic indexes. Fasting blood glucose, insulin levels, and liver parameters including alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. IGF-1 levels were significantly lower in the 3 patient groups compared with controls (P = 0.001). The HCV group demonstrated high HOMA-IR and HOMA-ß with a positive correlation between HOMA-IR and either HOMA-ß or fasting insulin (P < 0.001). In addition, a negative correlation was found between IGF-1 levels and both AST and ALT, and HOMA-IR was correlated positively with AST activity (P < 0.05). In HCV patients with detectable viremia, IGF-1 levels were correlated negatively with HOMA-ß (P < 0.01) and with HOMA-IR. However, this correlation did not reach statistical significance (P = 0.074). No significant correlation was found between HCV viral load and the studied parameters. In conclusion, low IGF-I levels might have a role in IR among HCV viremic patients.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Hepatite C Crônica/sangue , Hepatite C Crônica/complicações , Resistência à Insulina/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Adulto , Idoso , Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Glicemia/metabolismo , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Feminino , Hepatite C Crônica/virologia , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Pesquisa Translacional Biomédica , Carga Viral , Viremia/sangue , Viremia/complicações , Viremia/virologia
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