Niosomes are used in studies for drug delivery or gene transfer. However, their physical properties and features relative to liposomes are not well documented. To characterize and more rationally optimize niosome formulations, the properties of these vesicle systems are compared to those of liposomes composed of phosphatidylcholine and phosphatidylethanolamine lipids plus cholesterol. Niosomes are highly stable and only slightly more leaky than liposomes as assayed by calcein leakage; the permeability for ions (KCl) is higher than that of liposomes. Contrary to liposomes, the size of niosomes decreases substantially upon freezing in liquid nitrogen and subsequent thawing, as shown by cryo-EM and dynamic light scattering. The packing of niosomal membranes was determined by laurdan fluorescence and is slightly lower than that of liposomes. We did not succeed in the functional reconstitution of the L-arginine/L-ornithine antiporter ArcD2 in niosomes, which we attribute to the non-ionic nature of the surfactants. The antimicrobial peptides alamethicin and melittin act similarly on niosomes and liposomes composed of unsaturated components, whereas both niosomes and liposomes are unaffected when saturated amphiphiles are used. In conclusion, in terms of stability and permeability for drug-size molecules niosomes are comparable to liposomes and they may offer an excellent, inexpensive alternative for delivery purposes.

Recently, the self-assembly property of nonionic surfactants has been utilized to create vesicles as alternatives to liposomes. The aims of the present study were to investigate the impact of cholesterol on niosome bilayer properties and to evaluate niosome solubilization by Triton X-100 (TR) in the presence and absence of cholesterol. Niosomes were prepared using Span 80 and Tween 80 with or without cholesterol, and several structural studies were done. We compared both types of niosomes in their rigidity, permeability, surface tension, thermal properties, toxicity profile, and solubilization by the addition of several aliquots of TR. Efforts to achieve solubilizing parameters are also discussed. Our results indicate that cholesterol in niosomes increases membrane stability, decreases the fluidity of the membrane and also alters membrane permeability. Additionally, the solubilization process is illustrated by a three-stage model, in which the vesicle-to-micelle transition for niosomes is induced by the stepwise addition of TR. We show that cholesterol-containing niosomes need a higher amount of TR concentration for solubilization. To our best knowledge, this is the first report on niosome solubilization with TR. The results revealed the similarity of niosomal to liposomal systems, and we hope this encourages researchers to design more solubilization and protein reconstitution studies with niosomes.

The aim of this study was to determine the effect of opium on biochemical parameters in addicts with non‐insulin‐dependent diabetes mellitus (NIDDM). Twenty‐three males and 26 females between 35 and 65 years of age, with NIDDM, addicted to opium, were selected as the case group. Twenty‐three males and 26 females with NIDDM and no opium addiction served as controls. Fasting glucose, glycated haemoglobin (HbA1c), total cholesterol, high density lipoproteins ‐ cholesterol (HDL‐c), triglycerides (TGs), sodium (Na + ), potassium (K + ), calcium (Ca²⁺), iron (Fe²⁺), total iron binding capacity (TIBC), serum total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), uric acid and urea were measured in the serum of the two groups. Serum protein electrophoresis was also carried out. Compared to the control group, in addicted males with NIDDM, HbA1c, K + and Fe²⁺ were higher, and serum total protein, ALT and HDL‐c were lower. No significant difference was observed between other factors. Albumin was lower in addicts, but no significant difference was observed between the albumin/globulin ratios. In addicted females with NIDDM, serum total protein, TIBC, ALT and AST were lower compared to non‐addicts. Cholesterol tends to be lower in diabetic addicted males, HbA1c in addicted females and uric acid in addicted males was higher compared to non‐addicted diabetics. Their differences, however, were not significant. According to our results, smoking opium increases serum glucose and decreases HDL‐c, and thus adds to metabolic disorders in NIDDM patients. It also increases potassium and Fe²⁺ in males and decreases TIBC in females, and could therefore potentially interfere with water and iron metabolism.

It has been reported that the immune system undergoes age and gender changes. The aim of this study was to investigate the age- and gender-dependent changes of salivary IgA and IgE levels among healthy subjects. A total of 203 healthy individuals (aged 1-70 years) were enrolled in the study. Two milliliters of saliva were collected from all participants, and salivary IgA and IgE levels were measured by the ELISA technique. Mean salivary IgA levels were significantly higher in subjects aged 11-20 years as compared to subjects aged 1-10 years (P < 0.01). Mean salivary IgA levels increased with age up to the age of 60 years, and then slightly decreased in subjects aged 61-70 years. The frequency of subjects with detectable levels of salivary IgE and mean salivary IgE levels gradually increased with age, with maximum levels being observed in the 31-40 years age group and not changing significantly thereafter. The mean levels of salivary IgA and IgE in adults were significantly higher than those observed in children (P < 0.00001 and P < 0.05, respectively). No significant differences were observed between men and women regarding both salivary immunoglobulins. These results showed age-dependent changes of the salivary IgA and IgE levels. Gender had no effect on the salivary levels of IgA and IgE.