Some physico-chemical properties of aqueous solutions of Nα-acyl-L-histidine

Smith, G. D.; Barden, Roland E.

doi:10.1016/0009-3084(75)90011-0

Cited by 10 publications

(7 citation statements)

References 22 publications

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“…32 Derivatives of histidine are unusual surfactants in that the hydrophilic portion of the molecule is relatively large and contains both an anionic group (COO À ) and a cationic group (imidazole side chain), which gives this molecule an amphoteric nature by protonation-deprotonation to exhibit physicochemical behavior which is not typical of that exhibited by most NAAS. 33 Derivatives of histidine that respond to local pH changes in the body are helpful for solid tumor treatment. 2 Cationic amphiphiles containing histidine functionalities in their head group are serum compatible, nontoxic and endosome-disrupting, thus they can be used as a synthetic nonviral gene carrier.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

2010

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We report the construction of novel temperature-responsive assemblies based on a double hydrophilic block copolymer (consisting of a PEG block and a β-cyclodextrin-containing block, PEG-b-PCD) and poly(N-isopropylacrylamide) (PNIPAm). Thus formed nano-assemblies exhibit a spherical morphology and have a temperature-responsive loose core. The driving force for the formation of these assemblies was found to be the inclusion complexation interaction between the hydrophobic cavity of β-cyclodextrin and the isopropyl group of PNIPAm. The particle size of these assemblies changed reversibly in response to the external temperature change. The particle size also changed with the PNIPAm/PEG-b-PCD weight ratio. A model hydrophobic drug (indomethacin) was loaded into these assemblies with a high efficiency. An in vitro release study showed that the payload could be released in a sustained manner after an initial burst release. The release rate could be switched between high and low in an ON/OFF fashion by temperature. These results demonstrate that the nano-assemblies have high potential for applications in controlled drug delivery and biomedicine when temperature responsiveness is desired.

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Section: Introductionmentioning

confidence: 99%

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

2010

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“…Activation of IL‐17 and IL‐22 receptors on airway epithelial cells induces secretion of neutrophil chemotactic factors. In patients with COPD, sputum IL‐17A and IL‐22 levels are increased, and IL‐17A positively correlates with sputum neutrophils 197 . However, other studies present conflicting data concerning Th17 cytokine levels in COPD airways.…”

Section: Mechanisms Of Copdmentioning

confidence: 98%

“…In patients with COPD, sputum IL-17A and IL-22 levels are increased, and IL-17A positively correlates with sputum neutrophils. 197 However, other studies present conflicting data concerning Th17 cytokine levels in COPD airways. In most studies, blood IL-17A concentrations in COPD are higher compared to healthy smokers.…”

Section: Non-type 2 Immunity In Copdmentioning

confidence: 99%

Natural history and mechanisms of COPD

et al. 2021

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The natural history of COPD is complex, and the disease is best understood as a syndrome resulting from numerous interacting factors throughout the life cycle with smoking being the strongest inciting feature. Unfortunately, diagnosis is often delayed with several longitudinal cohort studies shedding light on the long ‘preclinical’ period of COPD. It is now accepted that individuals presenting with different COPD phenotypes may experience varying natural history of their disease. This includes its inception, early stages and progression to established disease. Several scenarios regarding lung function course are possible, but it may conceptually be helpful to distinguish between individuals with normal maximally attained lung function in their early adulthood who thereafter experience faster than normal FEV1 decline, and those who may achieve a lower than normal maximally attained lung function. This may be the main mechanism behind COPD in the latter group, as the decline in FEV1 during their adult life may be normal or only slightly faster than normal. Regardless of the FEV1 trajectory, continuous smoking is strongly associated with disease progression, development of structural lung disease and poor prognosis. In developing countries, factors such as exposure to biomass and sequelae after tuberculosis may lead to a more airway‐centred COPD phenotype than seen in smokers. Mechanistically, COPD is characterized by a combination of structural and inflammatory changes. It is unlikely that all patients share the same individual or combined mechanisms given the heterogeneity of resultant phenotypes. Lung explants, bronchial biopsies and other tissue studies have revealed important features. At the small airway level, progression of COPD is clinically imperceptible, and the pathological course of the disease is poorly described. Asthmatic features can further add confusion. However, the small airway epithelium is likely to represent a key focus of the disease, combining impaired subepithelial crosstalk and structural/inflammatory changes. Insufficient resolution of inflammatory processes may facilitate these changes. Pathologically, epithelial metaplasia, inversion of the goblet to ciliated cell ratio, enlargement of the submucosal glands and neutrophil and CD8‐T‐cell infiltration can be detected. Evidence of type 2 inflammation is gaining interest in the light of new therapeutic agents. Alarmin biology is a promising area that may permit control of inflammation and partial reversal of structural changes in COPD. Here, we review the latest work describing the development and progression of COPD with a focus on lung function trajectories, exacerbations and survival. We also review mechanisms focusing on epithelial changes associated with COPD and lack of resolution characterizing the underlying inflammatory processes.

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“…Antioxidant activity toward lipid peroxidation and excellent emulsifying activity of N -acyl- l -histidine have also been reported . In fact, histidine-derived amphiphiles behave as an unusual surfactant because the hydrophilic part contains a carboxylate group and an imidazole side chain, offering the molecule pH-responsive properties . This led us to design, synthesize, and examine gelation abilities of a series of N α -(4- n -alkyloxybenzoyl)- l -histidine amphiphiles (C n -OBH, see Chart for structures) in water.…”

Section: Introductionmentioning

confidence: 99%

A Smart Supramolecular Hydrogel of N^α-(4-n-Alkyloxybenzoyl)-l-histidine Exhibiting pH-Modulated Properties

2010

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Six L-histidine-based amphiphiles, N(alpha)-(4-n-alkyloxybenzoyl)-L-histidine of different hydrocarbon chain lengths, were designed, synthesized, and examined for their ability to gelate water. Four of members of this family of amphiphiles were observed to form thermoreversible hydrogels in a wide range of pH at room temperature. The structural variations were characterized by critical gelation concentration, gelation time, gel melting temperature (T(gs)), rheology, and electron microscopy. Among the amphiphiles, the n-octyl derivative showed better gelation ability in the studied pH range. The amphiphiles were found to have T(gs) higher than body temperature (37 degrees C) showing their stability. Also, relatively higher yield stress (>1000 Pa) values of the hydrogels show their higher strength. The effective gelator molecules self-assemble into fibrous structures. Scanning electron microscopic picture of the hydrogels revealed large ribbons with right-handed twist. Small-angle XRD and circular dichroism spectroscopy were also employed to characterize the hydrogels. It was observed that pi-pi stacking, hydrophobic interaction, amide hydrogen bonding, and solubility factor contribute to the stability and strength of the hydrogels.

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Some physico-chemical properties of aqueous solutions of Nα-acyl-L-histidine

Cited by 10 publications

References 22 publications

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

Natural history and mechanisms of COPD

A Smart Supramolecular Hydrogel of N^α-(4-n-Alkyloxybenzoyl)-l-histidine Exhibiting pH-Modulated Properties

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Some physico-chemical properties of aqueous solutions of Nα-acyl-L-histidine

Cited by 10 publications

References 22 publications

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

Natural history and mechanisms of COPD

A Smart Supramolecular Hydrogel of Nα-(4-n-Alkyloxybenzoyl)-l-histidine Exhibiting pH-Modulated Properties

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Product

Resources

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A Smart Supramolecular Hydrogel of N^α-(4-n-Alkyloxybenzoyl)-l-histidine Exhibiting pH-Modulated Properties