Improved physicochemical stability of fish oil nanoemulsion via a dense interfacial layer formed by hyaluronic acid-poly(glyceryl)10-stearate

This study aimed to synthesize a novel emulsifier, hyaluronic acid-poly(glyceryl)10-stearate (HA-PG10-C18), and employ it for the fabrication of nanoemulsions incorporating deep-sea fish oil to improve their apparent solubility and physicochemical stability. 1H NMR and FT-IR analyses indicated successful synthesis of HA-PG10-C18. Nanoemulsions of deep-sea fish oil loaded with HA-PG10-C18 (HA-PG10-C18@NE) were successfully fabricated by ultrasonic emulsification. The fixed aqueous layer thickness (FALT) of PG10-C18@NE and HA-PG10-C18@NE was determined and the FALT of both nanoemulsions was similar, while the surface density of HA-PG10-C18@NE (4.92 × 10-12 ng/nm2) is 60 % higher than that of PG10-C18@NE (3.07 × 10-12 ng/nm2). Notably, HA-PG10-C18@NE demonstrated an exceptional physicochemical stability when exposed to various stressed environmental conditions, especially its freeze-thaw stability. Moreover, after simulated in vitro digestion, the HA-PG10-C18@NE exhibited a comparatively greater liberation of free fatty acids (94.0 ± 1.7 %) when compared to the release observed in PG10-C18@NE (85.5 ± 2.2 %).

Preparation and characterization of glyceryl stearate/cassava starch composite for wax therapy

Glyceryl stearate and cassava starch (CS) composites were prepared by an esterification process. Formulations containing starch at various concentrations were prepared, being 1, 1.5, 3, 5, 10, 15, 20, and 30 % by weight, respectively. The characteristics of pH, moisture content, FTIR, melting point, latent heat, thermal energy storage, and specific heat capacity of composites were elucidated. The optimal formulation contained 1 % w/w CS, this indicated that the composite was able to maintain its temperature for 9.4 ± 0.5 min, with a melting temperature of 51.9 ± 0.3 °C, solidification temperature of 36.1 ± 1.6 °C, latent heat of fusion of 120 ± 10 J/g, and latent heat of solidification of 126 ± 3 J/g, and specific heat capacity of 2.6 ± 0.2 J/g.K. New bonds were formed in the composite structure of glyceryl stearate and CS at these levels. The composite had a pH that was safe for contact with human skin and a moisture content that could be kept stable for a prolonged time. The innovation and the advantages of a composite materials: 1. The main components are derived from natural materials. 2. Costs effective 3. Sustainability 4. Safety, and 5. Efficacy. Therefore, composites have a high potential as are replacement for paraffin wax bath therapy.

β-Carotene laden antibacterial and antioxidant gelatin/polyglyceryl stearate nano-hydrogel system for burn wound healing application

Worldwide, burn wounds are severe health issues prone to bacterial infections and challenging to treat with traditional wound dressings. Therefore, a highly desirable biological macromolecules-based wound dressing with good antioxidant, antibacterial, biocompatible, and a large surface area is required. Herein, aim to develop a biological macromolecules-based physically cross-linked gelatin/polyglyceryl stearate/graphene oxide (GPGO) hydrogel to treat burn wounds. Four sets of hydrogels were prepared by varying GO concentrations. FT-IR, FE-SEM, viscosity analysis, mechanical and thermal stability confirmed the successful preparation of hydrogels with desired properties. Further, β-carotene (0.5 mg/mL) was encapsulated in hydrogels to enhance the antioxidant activity, and a cumulative release as well as kinetics at pH 6.4 and 7.4 was performed. With an increase in GO concentration, hydrogels showed sustained release of β-carotene. Among all, GPGO-3 β hydrogel showed the highest antioxidant potency (57.75 %), hemocompatible (<5 %), cytocompatible (viable with NIH 3T3 cells), cell migration, proliferation, and in vitro wound healing. Also, GPGO-3 β hydrogel showed efficient antibacterial activity (%inhibition of 85.5 % and 80.2 % and zone of 11 mm and 9.8 mm against S. aureus and E. coli). These results demonstrated the ability of GPGO-3 β hydrogel as a promising candidate for burn wound healing applications.

In-utero evaluation of the fetal umbilical-portal venous system among fetuses with persistent right umbilical vein: Two-and three-dimensional ultrasonographic study

OBJECTIVE

The aim of this study was to describe the anatomy of the portal system in fetuses with persistent right umbilical vein (PRUV).

METHODS

Prospective observational study of fetuses diagnosed with PRUV. All patients underwent a comprehensive portal system anatomy scan supplemented by two-dimensional (2D) and three-dimensional (3D) color doppler modalities.

RESULTS

29 fetuses with PRUV were studied. We perceived an identical anatomical pattern in 28 fetuses. The right umbilical vein drains to the portal sinus (future right portal vein, RPV), which has a configuration of a left portal vein (LPV) in the normal left portal system, with three emerging branches: inferior (RPVi), medial (RPVm) and superior (RPVs). The RPV then courses to the left, towards the stomach to the point of the bifurcation of the main portal vein (MPV) to become the left portal vein. The LPV has an RPV configuration in a normal portal system with anterior (LPVa) and posterior (RPVp) branches. This anatomical layout mimics a mirror image of the normal anatomy of left portal system.

CONCLUSION

PRUV has unique umbilical portal venous anatomy, which is a mirror image of the normal left portal system. It can be demonstrated prenatally and serve as an additional tool for prenatal diagnosis of PRUV.

Power-Up for Mucoadhesiveness: Two Generations of Thiolated Surfactants for Enhanced Sticky Nanoemulsions

Nanoemulsions can be tuned toward enhanced gastro-intestinal retention time by incorporating thiolated surfactants into their surface. Tailoring the chemical reactivity of the thiol headgroup has major influence on mucoadhesive features of the nanoemulsion. Two generations of thiolated surfactants were synthetically derived from PEG-40-stearate featuring either a free thiol group or an S-protected thiol group. The surfactants were characterized regarding critical micelle concentration (CMC), hemolytic activity, and cytotoxicity. Subsequently, they were incorporated into nanoemulsions and the resulting nanoemulsions were characterized regarding particle size, polydispersity index (PDI), zeta potential, and time-dependent stability. Afterward, mucosal interactions as well as mucoadhesion on porcine intestinal mucosa were investigated. Successful synthesis of Cysteine-PEG-40-stearate (CYS-PEG-40-stearate) and MNA-Cysteine-PEG-40-stearate (MNA-CYS-PEG-40-stearate) was confirmed by 1H NMR spectroscopy. Both chemical modifications led to slightly elevated CMC values while preserving low cytotoxicity and hemotoxicity. Incorporation into nanoemulsions had minor influence on overall physical particle characteristics, while interactions with mucus and mucoadhesiveness of the nanoemulsions were drastically improved resulting in the rank order PEG-40-stearate < CYS-PEG-40-stearate < MNA-CYS-PEG-40-stearate. Accordingly, thiolated surfactants, especially S-protected derivatives, are versatile tools to generate highly mucoadhesive nanoemulsions.

Synthesis of Thermoplastic Mixed Chitin Esters

Mixed chitin esters, that is, chitin benzoate stearates, exhibiting thermoplasticity, were synthesized by the acylation of chitin using benzoyl and stearoyl chlorides in the presence of pyridine and N,N-dimethyl-4-aminopyridine for 1 h + 24 h at 100 °C in an ionic liquid, 1-allyl-3-methylimidazolium bromide. IR and 1H NMR spectroscopic analyses confirmed the formation of the desired chitin benzoate stearates. Powder X-ray diffraction analysis of the products indicated that the crystalline structures of the chitin main-chains and stearoyl side-chains were strongly affected by the benzoyl/stearoyl substituent ratios. Introducing a small number of benzoyl groups, in addition to a large ratio of stearoyl groups, contributed to disrupting the intrinsic chitin crystals and enabling the chitin main chains and stearoyl side chains to form regularly controlled layered and parallel arrays, respectively. The resulting products exhibited meting points, associated with regular stearoyl packings, and formed melt-pressed films during the melt-pressing process. These results suggest that chitin benzoate stearates with appropriate benzoyl/stearoyl substituent ratios exhibit thermoplasticity.

Rhamnopyranoside-Based Fatty Acid Esters as Antimicrobials: Synthesis, Spectral Characterization, PASS, Antimicrobial, and Molecular Docking Studies

The most widely used and accessible monosaccharides have a number of stereogenic centers that have been hydroxylated and are challenging to chemically separate. As a result, the task of regioselective derivatization of such structures is particularly difficult. Considering this fact and to get novel rhamnopyranoside-based esters, DMAP-catalyzed di-O-stearoylation of methyl α-l-rhamnopyranoside (3) produced a mixture of 2,3-di-O- (4) and 3,4-di-O-stearates (5) (ratio 2:3) indicating the reactivity of the hydroxylated stereogenic centers of rhamnopyranoside as 3-OH > 4-OH > 2-OH. To get novel biologically active rhamnose esters, di-O-stearates 4 and 5 were converted into six 4-O- and 2-O-esters 6-11, which were fully characterized by FT-IR, ¹H, and ¹³C NMR spectral techniques. In vitro antimicrobial assays revealed that fully esterified rhamnopyranosides 6-11 with maximum lipophilic character showed better antifungal susceptibility than antibacterial activity. These experimental findings are similar to the results found from PASS analysis data. Furthermore, the pentanoyl derivative of 2,3-di-O-stearate (compound 6) showed better antifungal functionality against F. equiseti and A. flavus, which were found to be better than standard antibiotics. To validate the better antifungal results, molecular docking of the rhamnose esters 4-11 was performed with lanosterol 14α-demethylase (PDB ID: 3LD6), including the standard antifungal antibiotics ketoconazole and fluconazole. In this instance, the binding affinities of 10 (-7.6 kcal/mol), 9 (-7.5 kcal/mol), and 7 (-6.9 kcal/mol) were better and comparable to fluconazole (-7.3 kcal/mol), indicating the likelihood of their use as non-azole type antifungal drugs in the future.

Transformation of Hydrophilic Drug into Oil-Miscible Ionic Liquids for Transdermal Drug Delivery

The transdermal delivery of hydrophilic drugs remains challenging owing to their poor ability to permeate the skin; formulation with oil media is difficult without adding chemical permeation enhancers or co-solvents. Herein, we synthesized 12 oil-miscible ionic liquid (IL) drugs comprising lidocaine-, imipramine-, and levamisole (Lev)-hydrochloride with fatty acid permeation enhancers, i.e., laurate, oleate, linoleate, and stearate as counterions. A set of in vitro and in vivo studies was performed to investigate the potency and deliverability of the transdermal drug formulations. All of the synthesized compounds were freely miscible with pharmaceutically acceptable solvents/agents (i.e., ethanol, N-methyl pyrrolidone, Tween 20, and isopropyl myristate (IPM)). In vitro permeation studies revealed that the oleate-based Lev formulation had 2.6-fold higher skin permeation capability than the Lev salts and also superior ability compared with the laurate-, linoleate-, and stearate-containing samples. Upon in vivo transdermal administration to mice, the peak plasma concentration, elimination half-life, and area under the plasma concentration curve values of Lev-IL were 4.6-, 2.9-, and 5.4-fold higher, respectively, than those of the Lev salt. Furthermore, in vitro skin irritation and in vivo histological studies have demonstrated that Lev-IL has excellent biocompatibility compared with a conventional ionic liquid-based carrier. The results indicate that oil-miscible IL-based drugs provide a simple and scalable strategy for the design of effective transdermal drug delivery systems.

Elemental, fatty acid, and protein composition of appendicoliths

Appendicoliths are commonly found obstructing the lumen of the appendix at the time of appendectomy. To identify factors that might contribute to their formation we investigated the composition of appendicoliths using laser ablation inductively coupled plasma mass spectroscopy, gas chromatography, polarized light microscopy, X-ray crystallography and protein mass spectroscopy. Forty-eight elements, 32 fatty acids and 109 human proteins were identified within the appendicoliths. The most common elements found in appendicoliths are calcium and phosphorus, 11.0 ± 6.0 and 8.2 ± 4.2% weight, respectively. Palmitic acid (29.7%) and stearate (21.3%) are the most common fatty acids. Some stearate is found in crystalline form-identifiable by polarized light microscopy and confirmable by X-ray crystallography. Appendicoliths have an increased ratio of omega-6 to omega-3 fatty acids (ratio 22:1). Analysis of 16 proteins common to the appendicoliths analyzed showed antioxidant activity and neutrophil functions (e.g. activation and degranulation) to be the most highly enriched pathways. Considered together, these preliminary findings suggest oxidative stress may have a role in appendicolith formation. Further research is needed to determine how dietary factors such as omega-6 fatty acids and food additives, redox-active metals and the intestinal microbiome interact with genetic factors to predispose to appendicolith formation.

Metabolic Alterations Differentiating Cardiovascular Maladaptation from Athletic Training in American-Style Football Athletes

PURPOSE

Metabolomics identifies molecular products produced in response to numerous stimuli, including both adaptive (includes exercise training) and disease processes. We analyzed a longitudinal cohort of American-style football (ASF) athletes, who reliably acquire maladaptive cardiovascular (CV) phenotypes during competitive training, with high-resolution metabolomics to determine whether metabolomics can discriminate exercise-induced CV adaptations from early CV pathology.

METHODS

Matched discovery ( n = 42) and validation ( n = 40) multicenter cohorts of collegiate freshman ASF athletes were studied with longitudinal echocardiography, applanation tonometry, and high-resolution metabolomics. Liquid chromatography-mass spectrometry identified metabolites that changed ( P < 0.05, false discovery rate <0.2) over the season. Metabolites demonstrating similar changes in both cohorts were further analyzed in linear and mixed-effects models to identify those associated with left ventricular mass, tissue-Doppler myocardial E ' velocity (diastolic function), and arterial function (pulse wave velocity).

RESULTS

In both cohorts, 20 common metabolites changed similarly across the season. Metabolites reflective of favorable CV health included an increase in arginine and decreases in hypoxanthine and saturated fatty acids (heptadecanoate, arachidic acid, stearate, and hydroxydecanoate). In contrast, metabolic perturbations of increased lysine and pipecolate, reflective of adverse CV health, were also observed. Adjusting for player position, race, height, and changes in systolic blood pressure, weight, and pulse wave velocity, increased lysine ( β = 0.018, P = 0.02) and pipecolate ( β = 0.018, P = 0.02) were associated with increased left ventricular mass index. In addition, increased lysine ( β = -0.049, P = 0.01) and pipecolate ( β = -0.052, P = 0.008) were also associated with lower E ' (reduced diastolic function).

CONCLUSIONS

ASF athletes seem to develop metabolomic changes reflective of both favorable CV health and early CV maladaptive phenotypes. Whether metabolomics can discriminate early pathologic CV transformations among athletes is a warranted future research direction.

Fatty Acid Synthase inhibitor TVB-3166 prevents S-acylation of the Spike protein of human coronaviruses

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other coronaviruses mediates host cell entry and is S-acylated on multiple phylogenetically conserved cysteine residues. Multiple protein acyltransferase enzymes have been reported to post-translationally modify spike proteins; however, strategies to exploit this modification are lacking. Using resin-assisted capture MS, we demonstrate that the spike protein is S-acylated in SARS-CoV-2-infected human and monkey epithelial cells. We further show that increased abundance of the acyltransferase ZDHHC5 associates with increased S-acylation of the spike protein, whereas ZDHHC5 knockout cells had a 40% reduction in the incorporation of an alkynyl-palmitate using click chemistry detection. We also found that the S-acylation of the spike protein is not limited to palmitate, as clickable versions of myristate and stearate were also labelled the protein. Yet, we observed that ZDHHC5 was only modified when incubated with alkyne-palmitate, suggesting it has specificity for this acyl-CoA, and that other ZDHHC enzymes may use additional fatty acids to modify the spike protein. Since multiple ZDHHC isoforms may modify the spike protein, we also examined the ability of the FASN inhibitor TVB-3166 to prevent S-acylation of the spike proteins of SARS-CoV-2 and human CoV-229E. We show that treating cells with TVB-3166 inhibited S-acylation of expressed spike proteins and attenuated the ability of SARS-CoV-2 and human CoV-229E to spread in vitro. Our findings further substantiate the necessity of CoV spike protein S-acylation and demonstrate that de novo fatty acid synthesis is critical for the proper S-acylation of the spike protein.

Investigation of Structural Features of Two Related Lipases and the Impact on Fatty Acid Specificity in Vegetable Fats

One of the indispensable applications of lipases in modification of oils and fats is the possibility to tailor the fatty acid content of triacylglycerols (TAGs), to meet specific requirements from various applications in food, nutrition, and cosmetic industries. Oleic acid (C18:1) and stearic acid (C18:0) are two common long fatty acids in the side chain of triglycerides in plant fats and oils that have similar chemical composition and structures, except for an unsaturated bond between C9 and C10 in oleic acid. Two lipases from Rhizomucor miehei (RML) and Rhizopus oryzae (ROL), show activity in reactions involving oleate and stearate, and share high sequence and structural identity. In this research, the preference for one of these two similar fatty acid side chains was investigated for the two lipases and was related to the respective enzyme structure. From transesterification reactions with 1:1 (molar ratio) mixed ethyl stearate (ES) and ethyl oleate (EO), both RML and ROL showed a higher activity towards EO than ES, but RML showed around 10% higher preference for ES compared with ROL. In silico results showed that stearate has a less stable interaction with the substrate binding crevice in both RML and ROL and higher tendency to freely move out of the substrate binding region, compared with oleate whose structure is more rigid due to the existence of the double bond. However, Trp88 from RML which is an Ala at the identical position in ROL shows a significant stabilization effect in the substrate interaction in RML, especially with stearate as a ligand.

A Confinement-Driven Nucleation Mechanism of Metal Oxide Nanoparticles Obtained via Thermal Decomposition in Organic Media

Thermal decomposition is a very efficient synthesis strategy to obtain nanosized metal oxides with controlled structures and properties. For the iron oxide nanoparticle synthesis, it allows an easy tuning of the nanoparticle's size, shape, and composition, which is often explained by the LaMer theory involving a clear separation between nucleation and growth steps. Here, the events before the nucleation of iron oxide nanocrystals are investigated by combining different complementary in situ characterization techniques. These characterizations are carried out not only on powdered iron stearate precursors but also on a preheated liquid reaction mixture. They reveal a new nucleation mechanism for the thermal decomposition method: instead of a homogeneous nucleation, the nucleation occurs within vesicle-like-nanoreactors confining the reactants. The different steps are: 1) the melting and coalescence of iron stearate particles, leading to "droplet-shaped nanostructures" acting as nanoreactors; 2) the formation of a hitherto unobserved iron stearate crystalline phase within the nucleation temperature range, simultaneously with stearate chains loss and Fe(III) to Fe(II) reduction; 3) the formation of iron oxide nuclei inside the nanoreactors, which are then ejected from them. This mechanism paves the way toward a better mastering of the metal oxide nanoparticles synthesis and the control of their properties.

Effect of dealumination on the acidity of zeolite Y and the yield of glycerol mono stearate (GMS)

Research on the production of Glycerol Monostearate from glycerol using dealuminated Zeolite Y catalysts has been carried out. Optimization of the dealumination process is conducted using the help of statistical software 10, where the variables used are acid concentration (5-7 M), temperature of dealumination (55-70 °C) and time of dealumination (2-6 h). The acidity characterization test of dealuminated Zeolite Y using ammonia and pyridine solution. Glycerol Monostearate yield was obtained by GC-MS test that was carried out on 2 samples zeolite Y catalyst with the highest value of total and surface acidity of zeolite Y which produced 2.18% and 4% yield of Glycerol Monostearate. The two samples showed that the greater the acidity, the GMS yield was also greater. Compared to previous studies it was found that ZSM-5 catalyst has a higher acidity value than zeolite Y so that the yield of Glycerol Monostearate is higher with the use of ZSM-5 than Zeolite Y.

Intercalation of modified zanthoxylum bungeanum maxin seed oil/ stearate in layered double hydroxide: Toward flame retardant nanocomposites

Zanthoxylum bungeanum Maxim Seed Oil (ZBMSO) is widely distributed in most parts of China, which cannot be edible and extensively consumed due to its high free fatty acids. This paper reports a rational route to utilization of ZBMSO in preparation of nanocomposites which can enhance leather flame retardancy and thermal stability. ZBMSO was synthesized through three-stage process, decoloration, acid reduction and sulfitation to prepare the modified ZBMSO fatliquoring agent (MZBMSO). Then nanocomposites based on MZBMSO and stearate-layered double hydroxide (s-LDH) were prepared via in-situ method. XRD and TEM results indicated that the MZBMSO intercalate into the galleries of s-LDH with uniform dispersion. Compared with MZBMSO, the leather treated by MZBMSO/s-LDH had a remarkable improvement on flame retardancy and superior softness which limiting oxygen index (LOI) increased from 23.6% to 28.0% and smoke density index decreased from 25 to 6.

Formulation and evaluation of verapamil hydrochloride loaded solid lipid microparticles

The present study aimed to produce verapamil hydrochloride-loaded solid lipid microparticles (SLM) by the w/o/w emulsion solvent evaporation technique, using diethyl ether as solvent phase, glyceryl monostearate as biodegradable polymer and Span 60 as surfactant. SLM of spherical shape were prepared by simple dilution of the emulsion with water. To increase the lipid load the process was conducted at 50 degrees C, and in order to reach sub-micron size, a high-shear homogenizer was used. The encapsulation efficiency of prepared SLM reached 74.29 +/- 0.76%. Particle size (98.55 +/- 1.42 microm), surface morphology (spherical) and drug loading efficiency (18.57 +/- 1.25% w/w) were investigated. And optimization of drug polymer ratio (3:1), nature and concentration of emulsion stabilizer in the external aqueous (0.1%), phase viscosity of external aqueous phase (0.5%), volume of external aqueous phase and stirring rate (1000 rpm) were detected. Analysis of microsphere content after processing showed that verapamil did not undergo any chemical modification within the micro-particles. The in-vitro release of verapamil from the microparticles was very low and an initial burst effect of 17% of the dose was observed. The slow release may help to avoid a high frequency of administration. The prepared solid lipid microparticles appear to have interesting perspectives as delivery systems for the oral administration of verapamil hydrochloride with improved half-life, improved bioavailability, and minimized local and systemic gastrointestinal disturbances of the drug.

Relationship between textural properties and sensory qualities of cookies made from medium- and long-chain triacylglycerol-enriched margarines

BACKGROUND

This study aims to investigate the textural properties and sensory qualities of cookies made from medium- and long-chain triacylglycerol (MLCT)-enriched margarines. Margarine with formulations of MLCT:palm olein:palm stearin, 60:30:10 and 70:20:10, were selected to produce cookies. The textural properties of cookies were determined using a texture analyser. Quantitative descriptive analysis (QDA) and acceptance test were carried out to describe the attributes and to evaluate the degree of liking of cookies, respectively.

RESULTS

Cookies made from MLCT-enriched margarines showed high values for hardness, fracturability, but also for cohesiveness and adhesiveness. Trained panelists rated the cookies made from MLCT-enriched margarines to be lower as compared to those made from commercial margarine for most of QDA attributes. However, cookies made from MOS 603010 and commercial margarines were scored similarly (P > 0.05) for all acceptance test attributes. Overall acceptability was found to be highly and negatively correlated for hardness, fracturability and cohesiveness (R(2) > 0.90). Principal component analysis showed that the taste attribute of cookies and the % solid fat content of margarine at 35 degrees C highly influenced the overall quality of the cookies.

CONCLUSION

Cookies made from MLCT-enriched margarines were not successfully produced. However, the findings obtained provide new perspectives in the production of low-calorie bakery fat.

Production of natural antioxidants from vegetable oil deodorizer distillates: effect of catalytic hydrogenation

Natural tocopherols are one of the main types of antioxidants found in living creatures, but they also have other critical biological functions. The biopotency of natural (+)-alpha-tocopherol (RRR) is 36% higher than that of the synthetic racemic mixture and 300% higher than the SRR stereoisomer. Vegetable oil deodorizer distillates (DD) are an excellent source of natural tocopherols. Catalytic hydrogenation of DD preconcentrates has been suggested as a feasible route for recovery of tocopherols in high yield. However, it is important to know whether the hydrogenation operation, as applied to these tocopherol-rich mixtures, is capable of preserving the chiral (RRR) character, which is critical to its biopotency. Fortified (i.e., (+)-alpha-tocopherol enriched) sunflower oil and methyl stearate, as well as sunflower oil DD, were fully hydrogenated using commercial Ni and Pd catalysts (120-180 degrees C; 20-60 psig). Products were analyzed by chiral HPLC. Results show that the desired chiral configuration (RRR) is fully retained. Thus, the hydrogenation route can be safely considered as a valid alternative for increasing the efficiency of tocopherol recovery processes from DDs while preserving their natural characteristics.

Clinical safety evaluation of a novel barrier protection cream

Patients with contact dermatitis require both preventive and therapeutic interventions to minimize their burden of disease. The ideal product would support resolution of inflamed skin without the use of glucocorticoids while protecting undamaged skin against further contact with irritants and antigens. COR806.805 (Tetrix Cream) is a novel barrier cream formulated for use on both lesional and nonlesional skin. Three clinical trials were conducted to evaluate the safety of this new product by studying sensitization, cumulative irritation, and effect on healing; a combined total of 265 participants completed the studies (210, 45, and 10, respectively), with no serious adverse events considered to be related to the product. Six mild adverse events were considered related or potentially related. As tested, COR806.805 is neither sensitizing nor irritating when applied to intact or lesional skin. Testing indicates that COR806.805 does not inhibit healing of allergic contact dermatitis lesions.

Clinical efficacy evaluation of a novel barrier protection cream

COR806.805 (Tetrix Cream) is a new barrier cream formulated using a unique patented technology. As a water-in-oil emulsion, COR806.805 has a water-resistant outer surface and water-soluble inner surface. Clinical studies have demonstrated the safety of COR806.805 in healthy adults with respect to sensitization, irritation, and effect on the healing of existing skin lesions. We report the results of trials undertaken to explore the substantivity and barrier protection properties of this new product when applied to clinically normal skin, as well as the beneficial effects when applied to inflamed skin, including skin affected by eczema. The results indicate that the cream establishes a barrier against common irritants, with persistence over 6 hours. The product appears effective and well-tolerated as a barrier and also may provide benefit in managing the itching and burning associated with contact dermatitis.

Crystallization and phase behavior of 1,3-propanediol esters

Polymorphic influences on the phase behavior of two types of binary mixtures of saturated monoacid 1,3-propanediol esters (PADEs), dipalmitate/distearate (PP/SS) and dimyristate/distearate (MM/SS) were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and by solid fat content (SFC), hardness and microscopy measurements. Three stacking modes have been found in the PP/SS binary system. Mixed SS-PP bilayers were detected in all mixtures, SS-SS bilayers in x(PP)=0.0-0.4 mixtures and PP-PP bilayers in x(PP)=0.6-0.1 mixtures. Two different but close beta polymorphs and one beta' polymorph were detected for this system. beta' was only detected in x(PP)=0.5-0.9 mixtures for the mixed bilayers. For the MM/SS binary system, only MM-MM and SS-SS bilayers were detected and both solid phases crystallized in two different beta forms. XRD data evidenced clearly that the MM and SS components were completely immiscible in the solid state. The phase diagrams constructed using DSC data, exhibited a typical eutectic-type phase boundary. The presence of eutectics, the shape of the solidus lines as well as the analysis of the individual enthalpies of melting indicated typical phase separation for both systems. A thermodynamic study based on the Hildebrand equation and using the Bragg-Williams approximation for non-ideality of mixing confirmed the phase separation in the solid phase and suggested that the PP and SS were miscible in the liquid phase and that SS formed an ideal mixing with MM. Avrami analysis of SFC vs. time curves indicated heterogeneous nucleation and spherulitic crystal development from sporadic nuclei, and suggested that the nucleation rate was higher for the mixture at the eutectic composition. The relative hardness was correlated with the enthalpies, the final SFC and the microscopy measurements.

Percolative Transport and Cluster Diffusion Near and Below the Percolation Threshold of a Porous Polymeric Matrix

PURPOSE

The purpose of this research was to develop a quantitative mass transport model to describe the release of a drug from a porous inert matrix dosage form near and below the percolation threshold for the system.

METHODS

Cumulative release profiles were generated for a series of tablets composed of a binary mixture of varying amounts of non-conducting (poly(vinyl stearate)) and conducting (benzoic acid) components. The porous microstructure was analyzed using re-constructed three-dimensional images of leached microtomed tablet sections. Poly(vinyl stearate) was characterized for transport properties, molecular weight and thermal properties.

RESULTS

Based on percolation theory, the binary matrix was determined to have a percolation threshold of 0.09 +/- 0.02. Transport, which could not be explained by "classical" percolation theory or surface diffusion alone, was observed below the percolation threshold for the system.

CONCLUSIONS

A model describing transport near and below the percolation threshold in matrices composed of two phases, polymer and drug, was developed. The percolation model developed accounts for diffusion within the porous structure and through the inert, insoluble polymeric amorphous regions of the matrix. The low percolation threshold and subsequently high coordination was concluded to be due to the biphasic classical porous and nonclassical polymeric diffusional transport mechanisms associated with the system studied.

In vitro study of microencapsulated isoflavone and beta-galactosidase

This study was designed to find the optimum conditions for isoflavone or beta-galactosidase microencapsulation and to examine the release efficiency of microcapsules in simulated gastrointestinal conditions. Coating materials were either medium-chain triacylglycerol (MCT) or polyglycerol monostearate (PGMS). The highest rate of microencapsulation was found at 15:1 (w/w) ratio of MCT to isoflavone or beta-galactosidase as 70.2 or 75.4%, respectively. When PGMS was used as the coating material, 91.5% beta-galactosidase was microencapsulated with 15:1 mixture (w/w). In vitro study, less than 6.3-9.3% of isoflavone was released in simulated gastric fluid (pH 2-5) during 1 h incubation. Comparatively, isoflavone release increased dramatically to 87.8% at pH 8 for 1 h incubation in simulated intestinal fluid and was maintained thereafter. The release of beta-galactosidase showed a similar trend to that of isoflavone. It appeared in the range of 12.3-15.2% at pH 2-5; however, it increased significantly to 80.6% as the highest value at pH 8. Among the released isoflavones, 53.5% was converted into the aglycone form of isoflavone at pH 8 for 3 h incubation. The present study indicated that isoflavone or beta-galactosidase could be microencapsulated with fatty acid esters and released effectively in simulated intestinal condition.

On the incorporation of the non-steroidal anti-inflammatory naproxen into cationic O/W microemulsions

Microemulsions (ME) containing hexadecyltrimethylammonium bromide (HTAB)/ethanol as surfactant, isopropylmyristate (IM) or butylstearate (BS) as oil phase and aqueous buffer were studied. Pseudo-ternary phase diagrams of the investigated systems were obtained at constant surfactant/cosurfactant molar ratio (1:5) by titration in order to characterize the proportions between the components to obtain clear systems. Oil in water microemulsions were prepared in a wide range of phase volume (phi). UV-vis absorption spectra of naproxen at pH 5.5 showed that the solubility of Np increases significantly in the presence of O/W ME in high phase volumes. For both, IM and BS microemulsions, the dynamic light scattering experiments showed that the size of the oil droplets remains constant in low values of phi, increasing abruptly in high phi values. Phase solubility study revealed that for both IM and BS microemulsions, the drug incorporation followed a straight-line profile in all range of phi. The data could be analyzed through the phase-separation model and the association constants (K) calculated varied from 27 to 90 M(-1), depending on the pH and on the microemulsion oil phase.

Influence of physicochemical properties on the patterns of association of a series of aliphatic esters of halofantrine with plasma lipoproteins

Although the association of lipophilic drugs with plasma lipoproteins has not been fully characterized, there are several reports of lipoprotein association being influential in pharmacokinetic and pharmacodynamic profiles of important therapeutic agents. The current studies utilized a series of aliphatic esters of halofantrine to evaluate the role of several physicochemical properties on the interaction of the different compounds with plasma lipoproteins. Density gradient ultracentrifugation techniques were employed to determine drug association in triglyceride rich (TRL), low-density (LDL) and high-density lipoproteins (HDL), under both fasted and post-prandial conditions. Compound solubility in medium or long chain triglycerides was a useful indicator of the extent of drug-lipoprotein association, particularly for the triglyceride rich lipoproteins (chylomicrons and very low-density lipoproteins). This is likely a function of the compounds being solubilized within the apolar (triglyceride and cholesterol ester) lipid core. However, molecular size also played an important role in determining lipoprotein distribution, particularly for association with the more protein abundant lipoproteins, such as HDL. Lipoprotein association of Hf analogues containing longer unsaturated esters was best correlated with total lipoprotein surface area rather than with lipoprotein core lipid volumes.

Microencapsulated iron for milk fortification

This study was designed to develop a microencapsulated iron that could be used to fortify milk and to determine the sensory properties of milk fortified with microencapsulated iron. Coating material was polyglycerol monostearate (PGMS), and selected core material was ferric ammonium sulfate. The highest efficiency of microencapsulation was 75% with 5:1:30 ratio (w/w/v) as coating to core materials to distilled water. Iron release was 12% when stored at 4 degrees C for 3 days. The TBA value was the lowest when 100 ppm of capsulated iron was added into milk and was significantly lower in capsulated groups compared with that in uncapsulated groups. In an in vitro study, only 3-5% of iron was released in simulated gastric fluid (pH 3, 4, 5, and 6). Comparatively, iron release increased dramatically from 12.3% (pH 5) to 95.7% (pH 8) for 60 min of incubation in simulated intestinal fluid. In a sensory analysis, most aspects except for metallic taste and color were not significantly different between control and capsulated iron fortified milk at 3 days of storage. However, between capsulated and uncapsulated groups, astringency, metallic, color, and overall scores were significantly different. The present study indicated that the use of microencapsulated iron with PGMS is effective for fortifying milk.

Microencapsulation of water-soluble isoflavone and physico-chemical property in milk

This study was carried out to investigate the addition of water-soluble isoflavone into milk by means of microencapsulation technique. The yield of microencapsulation, sensory attributes, and capsule stability of water-soluble isoflavone microcapsules in milk were measured. Coating materials used was polyglycerol monostearate (PGMS), and core material was water-soluble isoflavone. The encapsulation yield of water-soluble isoflavone with PGMS was 67.2% when the ratio of coating material to core material was 15:1. The rate of water-soluble isoflavone release from capsules was 18, 19, and 25% when stored at 4, 20, and 30 degrees C for 12 days in milk, respectively. In sensory evaluation, beany flavor and color of microencapsuled water-soluble isoflavone added milk were significantly different from uncapsuled water-soluble isoflavone added milk, however, bitterness was not significantly different. In vitro study, micro-capsules of water-soluble isoflavone in simulated gastric fluid with the range of 3 to 6 pHs were released 3.0-15.0%, however, the capsules in simulated intestinal fluid with pH 7 were released 95.7% for 40 min incubation time. In conclusion, this study provided that PGMS as coating materials was suitable for the microencapsulation of water-soluble isoflavone, and the capsule containing milk was almost not affected with sensory attribute.

Fatty Acid ethyl esters in scalp, pubic, axillary, beard and body hair as markers for alcohol misuse

AIMS

This study examined the possibility of using hair samples other than scalp hair for analysis of fatty acid ethyl esters (FAEE) as markers for alcohol misuse.

METHODS

Samples of scalp and pubic hair and, if available, axillary, beard and body hair of one teetotaller, five moderate social drinkers and 22 fatalities were analysed for FAEE by head-space solid-phase microextraction and gas chromatography-mass spectrometry. The sum of the concentrations of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate (C(FAEE)) in the hair samples was compared with information about the drinking behaviour of the individuals.

RESULTS

Although there were large differences in the analyte concentrations in hair from different sites in the same individual, cases of chronic excessive alcohol consumption were characterized by C(FAEE) > 1.0 ng/mg in almost all samples.

CONCLUSION

FAEE concentrations in hair other than scalp hair can be used as markers of chronic alcohol misuse.

Capillary electrochromatography with monolithic stationary phases: 1. Preparation of sulfonated stearyl acrylate monoliths and their electrochromatographic characterization with neutral and charged solutes

A novel monolithic stationary phase having long alkyl chain ligands (C17) was introduced and evaluated in capillary electrochromatography (CEC) of small neutral and charged species. The monolithic stationary phase was prepared by the in situ copolymerization of pentaerythritol diacrylate monostearate (PEDAS) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a ternary porogenic solvent consisting of cyclohexanol/ethylene-glycol/water. While AMPS was meant to support the electroosmotic flow (EOF) necessary for transporting the mobile phase through the monolithic capillary, the PEDAS was introduced to provide the nonpolar sites for chromatographic retention. Monolithic columns at various EOF velocities were readily prepared by conveniently adjusting the amount of AMPS in the polymerization solution as well as the composition of the porogenic solvent. The monolithic stationary phases thus obtained exhibited reversed-phase chromatography behavior toward neutral solutes and yielded a relatively strong EOF. For charged solutes (e.g., dansyl amino acids), nonpolar as well as electrostatic interaction/repulsion with the monoliths were observed in addition to electrophoretic migration. Therefore, for charged solutes, selectivity and migration can be readily manipulated by changing various parameters including the nature of the monolith and the composition of the mobile phase (e.g., pH, ionic strength and organic modifier). Ultrafast separation on the time scale of seconds of 17 different charged and neutral pesticides and metabolites were performed using short capillary columns of 8.5 cm x 100 microm ID.

Selective binding of albumin on stearyl poly(ethylene oxide) coupling polymer-modified poly(ether urethane) surfaces

A tri-block-coupling polymer of stearyl poly(ethylene oxide)-4,4'-methylene diphenyl diisocyanate-stearyl poly(ethylene oxide) (MSPEO), was used as a surface modifying additive (SMA) and the MSPEO-modified poly(ether urethane) (PEU) surfaces were prepared by the process of dip-coating. The surface analysis by XPS revealed the surface enrichment of poly(ethylene oxide) (PEO). On the coating-modified surfaces, the bovine serum albumin (BSA) adsorption, respectively, from the low and high BSA bulk concentration solutions was correspondingly characterized by the methods of radioactive 125I-probe and ATR-FTIR. The bovine serum fibrinogen (Fg)-adsorption from the Fg bulk solution and the BSA-Fg competing adsorption from the BSA-Fg binary solutions were also characterized by radioactive 125I-probe. The reversible BSA-selective in situ adsorption on MSPEO-modified PEU surfaces were achieved, and the performance of blood compatibility on the coating-modified surfaces was also confirmed, respectively, by plasma recalcification time (PRT) and prothrombin time (PT) tests.

Blends of stearyl poly(ethylene oxide) coupling-polymer in chitosan as coating materials for polyurethane intravascular catheters

To optimize the surface biocompatibility of the intravascular catheter, an amphiphilic coupling-polymer of stearyl poly (ethylene oxide) -co- 4,4'-methylene diphenyl diisocyanate-co- stearyl poly (ethylene oxide), for short MSPEO, was specially designed as the surface modifying additive (SMA). The blend of MSPEO in chitosan was coated on the outer wall of the catheters by the dip-coating method. The surface analysis was carried out by ATR-FTIR and contact angle measurements. The surface enrichment of MSPEO was confirmed. On the water interface, the larger the molecular weight of PEO was, the higher the surface enrichment. While on air interface, the case was the contrary. Three kinds of static test of clotting time, plasma recalcification time (PRT), prothrombin time (PT), and thrombin time (TT), as well as the static platelet adhesion experiment were carried out. The results indicated that the coated surface could resist the clotting effectively. In order to test the blood-compatibility of the coated catheters under a shear of blood flow, the dynamic experiment was performed through a closed-loop tubular system with the shear rate of 1500 s(-1). The results of blood regular testing at six different times (0, 5,10, 20, 30, and 60 min) indicated that the biocompatibility of the coating was nearly ideal. Finally, the SMA-MSPEO was proved to be non-chronic-toxic by animal experiments with rats and suitable as a coating material for clinical use.

[Quantitative characterization of adsorbed bovine serum albumin on modified surfaces of poly(ether urethane) materials using ATR-FT-IR spectroscopy]

Attenuated total reflection (ATR) FT-IR spectroscopy was used to quantitatively characterize the extent of bovine serum albumin (BSA) adsorbed on the surface-coating-modified poly(ether urethane) (PEU) matrix. The two surface modifying additives (SMA) were respectively a tri-block-coupling-polymer of stearyl poly (ethylene oxide)-4,4'-methylene diphenyl diisocyanate-stearyl poly(ethylene oxide), for short MSPEO, and another similar block-coupling polymer with the Cibacron Blue F3G-A endgroups, for short cibaMPEO. The experiments of static BSA adsorption were composed by two parts. One was static isothermal adsorption, and the other was static adsorption kinetics. The quantitative characterization was based on the optical principles of FT-IR, method of experiment and index of the apparatus, by which the enhancement of BSA adsorption on the SMA-modified surfaces was confirmed.

Stearyl poly(ethylene oxide) grafted surfaces for preferential adsorption of albumin

An ideal surface for many biomedical applications would resist non-specific protein adsorption while at the same time triggering a specific biological pathway. Based on the approach of selectively binding albumin to free fatty acids, stearyl groups were immobilized onto poly(styrene) backbone via poly(ethylene oxide) side chains. X-ray photoelectron spectroscopy (XPS) analysis indicates substantial surface enrichment of the stearyl poly(ethylene oxide) (SPEO). In an aqueous environment, the surface rearrangement is limited, as proved by dynamic contact angle tests. The comb-like copolymer presents a special hydrophobic surface with high SPEO surface density, which may be due to the 'tail like' SPEO architecture at the copolymer/water interface. Protein adsorption tests confirm that the comb-like surfaces adsorb high levels of albumin and resist fibrinogen adsorption very significantly. The surfaces prepared in this research attract and reversibly bind albumin due to the synergistic action of the PEO chains and the stearyl end groups.

TerplexDNA gene carrier system targeting artery wall cells

The development of non-viral gene carrier systems becomes more urgent and important due to the major biosafety considerations involved with application of viral vector systems for clinical gene therapy. We recently developed a novel non-viral gene carrier system, termed TerplexDNA, which showed high gene transfer efficiency when compared to the lipofectamine gene delivery system both in HepG2 and A7R5 cell lines in vitro. In present studies, we demonstrated that the TerplexDNA gene carrier system specifically delivered the reporter genes (LacZ and Luciferase) and therapeutic gene (hrVEGF(165) cDNA) into bovine aortic artery wall cells (endothelial cells and smooth muscle cells) by receptor mediated endocytosis. We found that the transfection efficiency to these primary artery wall cells, when mediated by the TerplexDNA system, was dose-dependent, saturable and was significantly inhibited by excess free LDL. The transfection efficiency of the TerplexDNA gene carrier system was approximately 60-fold higher than that of the lipofectamine gene carrier system. The TerplexDNA gene carrier system is a useful and promising tool for artery wall gene transfer.

Augmentation of myocardial transfection using TerplexDNA: a novel gene delivery system

Gene therapy is a potential new strategy for the treatment of cardiovascular disease. The most efficacious method of gene delivery remains a key hurdle to effective gene therapy. We present the application of a novel, nonviral gene delivery system (TerplexDNA) to augment myocardial transfection. The hearts of New Zealand white rabbits were injected with reporter genes, luciferase cDNA or beta-galactosidase cDNA, either as naked plasmid DNA or plasmid DNA complexed with stearyl-poly(L-lysine)-low density lipoprotein (TerplexDNA). Three day left heart myocardial cell lysates produced 44571 +/- 8730 RLU (RLU = total light units/mg protein) for the TerplexDNA luciferase rabbits versus 1638 +/- 567 RLU for the naked luciferase rabbits (P = 0.002). Thirty days after injection, myocardial lysates produced 677 +/- 52 RLU for the TerplexDNA luciferase hearts versus 18 +/- 3 RLU for the naked luciferase hearts (P = 0.002). Histologic analysis of the hearts transfected with beta-galactosidase showed that TerplexDNA increased the area and depth of transfection compared with the naked plasmid DNA alone. The hearts of Sprague-Dawley rats were injected in a similar fashion and analyzed at 1, 3, 5, 10, 15, 25 and 30 days after injection. The naked luciferase injected hearts showed transient elevation of luciferase activity to day 5 but fell back to baseline levels after that time-point. The TerplexDNA luciferase injected hearts had significantly elevated luciferase activity to 30 days. The Terplex gene delivery system significantly augments myocardial transfection compared with a naked plasmid DNA system alone. The advantage in transfection efficiency appears to be related to the unique properties of the TerplexDNA carrier molecule. The TerplexDNA delivery system represents a novel means to augment transfection of the myocardium.

Melt pelletisation of a hygroscopic drug in a high shear mixer. Part 2. Mutual compensation of influence variables

The process of melt pelletisation in a Diosna P10 high shear mixer was examined for sodium valproate and glycerol monostearate. The effects of binder concentration, impeller speed and massing time on mean granule size, size distribution and liquid saturation were investigated. Spherical pellets of almost similar size and size distribution were obtained after 20 min of massing time, with a binder content from 3.1 to 14.1% w/w by adjusting the impeller speed. Granule growth was observed at low levels of binder concentration and liquid saturation (<80%) which is untypical for melt granulation. The liquid saturation seemed to have no major influence on the final pellet size. Additional, mutually compensating effects on granule growth were found to be impeller speed and massing time for a fixed binder concentration. Low levels of both, binder concentration and impeller speed, allowed for good control of the process. The amount of water adsorbed by the hygroscopic drug was found to accelerate granule growth.

The plasma borne free fatty acids rapidly enter the hepatocellular nuclei

Long-chain free fatty acids (FA) were shown to exert a regulatory function in the nucleus. However, the route of their entry remains uncertain. The aim of the present study was to examine whether the extracellular FA enter the hepatocellular nuclei. The experiments were carried out in vivo and in vitro. Intravenous administration of albumin-bound [14C]-palmitic and [14C]-linoleic acid resulted in rapid accumulation of the labels in the nuclear lipids. Unesterified [14C]-palmitic acid represented 22.4 +/- 1.7 and [14C]-linoleic acid 17.6 +/- 1.3 percent of the total lipid radioactivity. In vitro, confocal laser scanning microscopy was used to examine 12-NBD-stearate (a fluorescent derivative of stearate) translocation into the nuclei of isolated hepatocytes. It was found that 12-NBD stearate enters the nucleus and that this uptake depends on the extracellular and/or cytoplasmic concentration. It is concluded that factors (e.g. dietary) leading to alterations in the plasma FA composition and content can result in rapid changes of the nuclear FA pool and thus regulate certain nuclear processes.

Evaluation of stearate-graphite paste electrodes for chronic measurement of extracellular dopamine concentrations in the mammalian brain

Chronoamperometric procedures, in combination with pharmacological treatments, were used to verify whether stearate-modified graphite paste recording electrodes (SGEs) could measure basal extracellular dopamine (DA) concentrations in the striatum of awake rats over a 3-week period of implantation. Baseline chronoamperometric signals were unaffected by systemic injections of ascorbate (AA) or the monoamine oxidase inhibitor pargyline, or by intraventricular infusions of the AA degrading enzyme AA-oxidase. In contrast, systemic injections of d-amphetamine or nomifensine increased, and gamma-butyrolactone decreased, the signal in a reproducible fashion over a similar test period. In addition, 6-hydroxydopamine lesions of the nigrostriatal DA pathway attenuated the ability of d-amphetamine to increase, and gamma-butyrolactone to decrease, the chronoamperometric signal. In separate studies, reverse microdialysis, performed with dialysis probes implanted directly adjacent to SGEs in the striatum, permitted the assessment of electrode selectivity, sensitivity, response linearity, and detection limits to DA. Perfusion of the probe with normal Ringer solution (5 microliters/min) decreased the baseline chronoamperometric signal by 10 nA. Comparable decreases in the baseline signal were observed after systemic injections of gamma-butyrolactone or medial forebrain bundle infusions of tetrodotoxin, suggesting these decreases reflected depletion of extracellular DA to levels below the electrode's detection limit. Reverse dialysis with high concentrations of AA, DOPAC, 5-HT, or 5-HIAA, failed to reverse the decrease in the chronoamperometric signal induced by dialysis. In contrast, reverse dialysis with a physiologically relevant range of DA concentrations, in rats pretreated with the DA uptake blocker nomifensine, increased the chronoamperometric signal in a linear fashion with a detection threshold of < 20 nM. Combined, these results indicate that the baseline chronoamperometric signals recorded at +0.20 V in the striatum with SGEs do not reflect changes in extracellular concentrations of AA, DA metabolites, or indoles, but rather represent neuronally mediated nanomolar changes in extracellular DA concentrations, even after extended periods of implantation in brain tissue.

Indium-111 labeling of low density lipoproteins with the DTPA-bis(stearylamide): evaluation as a potential radiopharmaceutical for tumor localization

In order to use the LDL receptor pathway to target radionuclides to cancer sites for imaging and diagnostic purposes, a labeling procedure of LDL with 111In using the DTPA-bis(stearylamide) (L) has been developed. This bifunctional ligand is intended to be incorporated into the phospholipid monolayer of LDL and to specifically chelate the In3+ cation at the surface. The ligand was incorporated into LDL in buffered medium with a 65-80% yield. The L-LDL samples are stable over a 24 h period when examined by dialysis, allowing their storage before indium-111 radiolabeling. In vitro studies of In-L-LDL particles show that indium labeling is rapidly achieved (1 h). More than 85% of the indium atoms are bound to the chelating functions of the incorporated DTPA derivatives and less than 10% to the nonspecific complexation sites of LDL (e.g., protein residues). After incubation in human serum, the indium activity recovered in the LDL fraction of In-L-LDL samples (95%) is much higher than in In-LDL samples (35%), pointing out the strong stabilizing chelating effect of the ligand. Competitive binding studies show that In-L-LDL are recognized by LDL receptors of A549 cells like native LDL when the In-L/LDL ratio varies from 5 to 30. All these in vitro experiments demonstrate that the In-L-LDL conjugates possess properties suitable for further work with in vivo experiments.

Smoothed acyl chain orientational order parameter profiles in dimyristoylphosphatidylcholine-distearoylphosphatidylcholine mixtures: a 2H-NMR study

The accommodation of chain-length mismatch in liquid crystal phase bilayers was examined by using deuterium nuclear magnetic resonance to obtain smoothed orientational order parameter profiles for acyl chains of both components in binary lipid mixture bilayers. Mixtures of dimyristoylphosphatidylcholine (DMPC) and distearoylphosphatidylcholine (DSPC) covering a range of compositions were prepared with either DSPC acyl chains or DMPC acyl chains perdeuterated. Orientational order parameters in the plateau regions of the smoothed profiles for both components were found to increase smoothly with increasing DSPC concentration. The orientational order parameters in the DSPC-smoothed profile were found to be slightly higher than corresponding values for DMPC over a wide range of bilayer composition. The shapes of the smoothed profiles for both components were found to be sensitive to bilayer composition. At low DSPC concentration, DSPC methylene deuterons near the bilayer center display a secondary plateau at low orientational order. At high DSPC concentration, the plateau of the DMPC-smoothed profile is stretched slightly. The concentration dependence of the smoothed profiles at low DSPC concentration appears to be consistent with a picture in which the last few segments of the DSPC chain cross the bilayer midplane, on average, but remain very disordered.

Effect of dietary hydrogenated corn oil (trans-octadecenoate rich oil) on plasma and hepatic cholesterol metabolism in the hamster

The effect of dietary hydrogenated corn oil (trans-octadecenoate-rich oil) on plasma cholesterol and triglyceride concentrations was compared with dietary palmitic acid in hamsters given a cholesterol-rich diet. The addition of dietary palmitic acid and hydrogenated corn oil accelerated the increase in plasma VLDL- and LDL-cholesterol levels and plasma triglyceride level induced by dietary cholesterol loading. Dietary cholesterol, palmitic acid and hydrogenated corn oil showed no effect on plasma HDL-cholesterol concentration. A decrease in hepatic LDL receptor activity was seen in animals fed a diet supplemented with cholesterol in combination with palmitic acid or hydrogenated corn oil in comparison with animals fed a diet supplemented with cholesterol alone. Hydrogenated corn oil (trans-octadecenoate-rich oil) appears to potentiate the effect of dietary cholesterol in elevating the plasma VLDL- and LDL-cholesterol levels through the suppression of hepatic LDL receptor activity. trans-Octadecenoate in dietary hydrogenated corn oil may be as atherogenic as dietary palmitic acid due to a suppression of hepatic LDL receptors in the presence of dietary cholesterol loading.

The effect of the synthetic lecithin analogue, dimethyl-DL-2, 3-distearolyoxypropyl-2'hydroxylethylammonium acetate, on cytolytic T lymphocyte (CTL) activity

The effect of the synthetic lecithin analogue, dimethyl-DL-2, 3-distearolyoxypropyl-2'hydroxylethylammonium acetate, on CTL cytolytic activity was studied. The analogue significantly inhibits H-2b anti H-2d cytolytic T lymphocytes at concentrations which do not impair lymphocyte viability, protein synthesis, or RNA synthesis. At these concentrations the inhibition is reversible upon removing the analogue. Thus, the inhibition produced by analogue simply is not a result of analogue toxicity. At higher concentrations of the analogue, CTL inhibition is very pronounced; however at these higher concentrations there is evidence of non-specific toxicity of the analogue on CTL.

A new affinity adsorbent for the purification of phospholipases A1 and A2 from animal venoms

Dimethyl-DL-2,3-distearoyloxy-propyl-2'-hydroxy-ethylammonium++ + (Rosenthal's inhibitor) was coupled to carboxyhexyl-Sepharose 4B, through carbodiimide chemistry. Phospholipase A2 from Heloderma horridum horridum and Crotalus adamanteus bind to the immobilized ligand in the presence of Ca2+ and can be easily eluted under acidic conditions or in the presence of a chelating agent, respectively. This affinity media proved to be effective also in the purification of a Ca2(+)-independent phospholipase A1 from vespid venom.

Studies on sucrose-palmitate-stearate-containing vesicles encapsulating the cytostatic drug methylglyoxal-bis-guanyl-hydrazone

Vesicles prepared from sucrose-palmitate-stearate and cholesterol encapsulating the anticancer drug methylglyoxal-bis-guanylhydrazone, were investigated. Treatment with drug-loaded vesicles of this composition in a q.d. 1-4 schedule resulted for murine leukemias P388 in nearly the same increase in life span as the corresponding dose of the free drug. Even very high dosages of sucrose-palmitase-stearate (up to 480 mg.kg-1.d-1) were tolerated by mice.

Effective inhibition of viral reproduction by hydrophobised antiviral antibodies

A method is proposed for the inhibition of viral reproduction in cells by means of fatty-acylated antiviral antibodies which, in contrast to the unmodified antibodies, have the ability to enter the cells. The potential of this technique is demonstrated in experiments involving inhibition of the reproduction of various strains of influenza virus and respiratory syncytial virus.