Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level.

Soluble CD40 ligand is associated with angiographic severity of coronary artery disease in patients with acute coronary syndrome.

BACKGROUND: Recently, studies have disclosed soluble CD40 ligand (sCD40L) during atherosclerosis development and plaque destabilization. The objective of the present study was to test the hypothesis that sCD40L levels are higher in acute coronary syndrome (ACS) patients with a greater extent of angiographic coronary involvement. METHODS: This cross-sectional study examined ACS patients who underwent coronary angiography by measuring their sCD40L levels. In order to estimate the serum levels of sCD40L, 10 ml of peripheral venous blood was drawn within 24 hours of admission. sCD40L levels were measured using an enzyme-linked immunosorbent assay (ELISA, RapidBio, West Hills, CA, USA). Demographic data, presence of concomitant diseases, ACS characteristics, and angiographic findings were evaluated. A review of medical records and patient interviews were conducted to assess coronary risk factors. And the severity of coronary artery disease was evaluated using the Gensini score index. RESULTS: Two hundred and eighty-nine patients were included in the study, of whom 186 were male, with an average age of 64.1 ± 10.0 years. Median sCD40L levels were 1.7 ng/ml (0.3-7.3 ng/ml) and Gensini scores were 50 (0-228). After adjusting for demographic variables and cardiovascular risk factors, the Gensini score was associated with the natural logarithm of the sCD40L level (Coefficient b = 0.002, 95% CI 0.000-0.003, P = 0.029). CONCLUSION: sCD40L levels were independently associated with angiographic severity of coronary artery disease in patients with ACS.

Heat shock protein 70 acts as a potential biomarker for early diagnosis of heart failure.

Early identification for heart failure (HF) may be useful for disease modifying treatment in order to reduce heart disease progression or even to reverse it. In our previous studies, we have revealed a group of heat shock proteins (HSPs) which might be related to neonatal rat cardiomyocyte hypertrophy by proteomic approach. Here, we confirm that HSPs, including HSP27 and HSP70, altered in the early stage of cardiac remodeling in vivo animal model. Furthermore, plasma concentrations of those HSPs and their potential screening value were evaluated at different stages in 222 patient subjects. Plasma HSP27, HSP70 and HSP90 were measured using enzyme-linked immunosorbent assay. Results indicate that HSP70 was positively correlated to the severity (progression) of HF (r = 0.456, p<0.001). The area under the rate of change (ROC) curve was 0.601 (p = 0.017) in patients with stage B HF and 0.835 (p<0.001) in those with stage C HF. However, HSP27 and HSP90 did not display significant changes in any stage of HF in this study. Taken together, plasma concentrations of HSP70 elevated with the progression of HF and might act as a potential screening biomarker for early diagnosis of HF.

Theory analysis of mass spectra of long-chain isocyanates.

Electron impact mass spectra of four long-chain isocyanates, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate and octadecyl isocyanate, were obtained with a GCT high-resolution time-of-flight mass spectrometer. The four isocyanates studied gave a common base peak of m/z 99, which suggested the formation of a stable six-membered ring structure to decentralize the positive charge. Quantum-mechanical energy calculation justified that the six-membered ring base peak had the lowest energy. The positive charge assigned during the fragmentation of the radical cation, and the relative intensity of the fragment ion peaks, were explained by quantum-mechanical calculations as well.

Structure-function relationship research of glycerol backbone-based cationic lipids for gene delivery.

Transfection activities of two series of synthetic glycerol backbone-based cationic lipids were studied as gene delivery carriers. The variable length of hydrocarbon chains, diverse quaternary ammonium heads, different linkage, as well as alternative anion combined with them allowed to find how these factors affect cationic lipids on their gene delivery performance. The structure-function relationship of the synthetic glycerol backbone-based cationic lipids was discussed, and the transfection efficiency of some of the cationic liposomes was superior or parallel to that of two commercial transfection agents.

Carbamate-linked cationic lipids for gene delivery.

Series of cationic lipids 1a-p, with variable length of hydrocarbon chains, alternative quaternary ammonium heads, carbamate linkages between hydrocarbon chains and quaternary ammonium heads, as well as different anion combined with them, were synthesized for liposome-mediated gene delivery. Two plasmid DNAs, pGL3-control and pGFP-N2, were transferred by cationic liposomes formed from the above cationic lipids into five mammalian cell lines, and the transfection efficiency of some of the cationic liposomes was superior or parallel to that of two commercial transfection agents, Lipofectamine2000 and Sofast.

[The mechanism and efficiency affecting factor of cationic liposome transfection].

Cationic liposome is a greatly promising gene carrier. In this paper, the structure trait of cationic liposome was briefly introduced, the mechanism of cationic liposomes mediated gene delivery and the main influencing factor of transfection efficiency in the transfection process were discussed chiefly.

Synthetic diether-linked cationic lipids for gene delivery.

Quaternary ammonium lipids 2a-p, with diether linkages between hydrocarbon chains and their ammonium headgroups, were synthesized as potential vectors for cationic liposome-mediated gene delivery. Varying the length of carbon chains and quaternary ammonium heads as well as different anionic complexes will enable the study of the structure-function relationships of these cationic lipids in terms of gene delivery properties.

Synthesis and characterization of a series of carbamate-linked cationic lipids for gene delivery.

A series of pH-sensitive lipids, la-h [(2,3-bis-alkylcarbamoyloxy-propyl)-trialkylammonium halide] and 2a-d (1-di-methylamino-2,3-bis-alkylcarbamoyloxy-propane), with carbamate linkages between the hydrocarbon chains and an ammonium or tertiary amine head, were synthesized for liposome-mediated gene delivery. The variable length of the carbon chains and the quaternary ammonium or neutral tertiary amine heads allowed us to identify the structure-function relationship showing how these factors would affect cationic lipids in gene delivery performance.

Synthesis of carbamate-linked lipids for gene delivery.

Series of lipids 1a-d and 2a,b, with carbamate linkages between hydrocarbon chains and ammonium or tertiary amine head, which were pH sensitive, were synthesized for liposome-mediated gene delivery. The variable length of carbon chains and quaternary ammonium or neutral tertiary amine heads allowed to find the structure-function relationship of how these factors affect cationic lipids on gene delivery performance.

Cationic compounds used in lipoplexes and polyplexes for gene delivery.

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Many cationic lipids and cationic polymers naturally occurred or synthesized have been used for gene transfer. They have the advantages over viral gene transfer as non-immunogenic, easy to produce and not oncogenic. These cationic compounds, however, have the major limitations of inefficient transfection and toxicity to cells. For overcoming these problems, many new cationic compounds were developed since the first cationic lipid, DOTMA, was found usage in gene therapy. This article reviews cationic lipids for gene therapy from chemistry viewpoint and we classify these compounds as monovalent cationic lipids, polyvalent cationic lipids, cationic polymers, guanidine containing compounds, cationic peptides and cholesterol containing compounds, and hope to provide suggestions on the development of this variety of cationic compounds through the discussion.