In vitro stimulation of macrophages by quadrol [N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine]

Quadrol-Pd(II) complexes: phosphine-free precatalysts for the room-temperature Suzuki-Miyaura synthesis of nucleoside analogues in aqueous media

Commercially available Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPEN), has been used for the first time as a N^N-donor neutral hydrophilic ligand in the synthesis and characterization of new water soluble palladium(II) complexes containing chloride, phthalimidate or saccharinate as co-ligands. [PdCl2(THPEN)] (1) [Pd(phthal)2(THPEN)] (2), [Pd(sacc)2(THPEN)] (3) and the analogous complex with the closely related N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (THEEN) [Pd(sacc)2(THEEN)] (4) were efficiently prepared in a one-pot reaction from [PdCl2(CH3CN)2] or Pd(OAc)2. Structural characterization of 1 and 3 by single crystal X-ray diffraction produced the first structures reported to date of palladium complexes with Quadrol. The resultant palladium complexes are highly soluble in water and were found to be effective as phosphine-free catalysts for the synthesis of functionalized nucleoside analogues under room-temperature Suzuki-Miyaura cross-coupling conditions between 5-iodo-2'-deoxyuridine (& 5-iodo-2'-deoxycytidine) with different aryl boronic acids in neat water. This is the first report of the coupling process performed on nucleosides in water at room temperature.

Development of a Novel Hydrophilic, Biocompatible Adhesive

The synthesis of two novel hydrogel adhesive films, poly(butoxy- Entprol) and poly(butoxy/ethylene-Entprol) was accomplished by crosslinking either epoxy end-capped oligomeric-butoxy-Entprol or epoxy end-capped oligo meric-butoxy/ethylene-Entprol with 5-10 mole% diethylenetriamine. The two oligomers with Mn 1700 to 5000 were obtained in a 78-87% yield, by the reac tion of one equivalent of N,N'-bis(2-hydroxypropyl)ethylenediamine with either one equivalent of 1,4-butanediol diglycidyl ether or one equivalent of a 1:1 mole ratio mixture of 1,2,7,8-diepoxyoctane and 1,4-butanediol diglycidyl ether.

Peel adhesion to glass for poly(BE) and poly(BEE) gave peel forces of 12.02 and 13.61 N, respectively, as compared to five acrylate adhesives, ranging from 4.90-11.56 N. Poly(BE) had superior adhesion to skin (3.45 N) compared to poly(BEE) (0.97 N) and the acrylate-based adhesives (0.79-2.64 N). In addition, fully hydrated poly(BE) and poly(BEE) have both a high water uptake (971% and 630%, respectively) and equilibrium water content (90% and 86%, respec tively). Both films lose adhesion with progressive hydration. These hydrogels actively support the growth of 3T3 fibroblasts and SCC-13 epithelial cells. These results strongly support the potential of these films as single-layered adhesive hydrogel dressings.

Copolymers of Hydroxyethyl Methacrylate with Quadrol Methacrylate and with Various Aminoalkyl Methacrylamides as Fibroblast Cell Substrata

Universal application of hydrophilic hydrogels like poly(hydroxy ethyl methacrylate) [p(HEMA)], as biomaterials is limited due to their inabil ity to favorably affect eukaryotic cell growth. In an attempt to favorably manipulate surface properties, a series of HEMA copolymers was made with 10-40% aminoethyl methacrylamide (AEMA), aminopropyl methacrylamide (APMA), Quadrol methacrylate (QM), N,N'-bis(2-hydroxypropyl)aminoethyl meth acrylamide (HPAEMA) or dimethylaminoethyl methacrylate (DMAEMA). Balb/c 3T3 fibroblast cell growth was observed on HEMA:AEMA (80:20), HEMA:QM (80:20) and HEMA:HPAEMA (90:10) copolymers. Cell growth on HEMA: AEMA (80:20) was comparable to HEMA:DMAEMA (60:40). HEMA copolymers containing APMA, a homolog of AEMA, exhibited cytotoxicity.

Cationic groups of primary and tertiary amines present in the HEMA copoly mer hydrogels favorably contribute to the support of cell growth. The effect of hydroxyl groups on cell growth appears to be favorable. The extent of cell growth varied with the concentration of the cationic groups in the hydrogel.

The cytotoxicity of the HEMA:APMA copolymers as compared with the bio compatibility of the HEMA:AEMA copolymers suggests that the length of the branch from the polymer chain for copolymers with primary amino groups may be a critical factor in biocompatibility.

Degradable poly(amino alcohol esters) as potential DNA vectors with low cytotoxicity

The synthesis of a new degradable polymer system, poly(amino alcohol esters) and the resulting polymers' potential for use in gene transfection vectors are reported. The polymerization proceeded in a one step reaction from commercially available bis(secondary amines) monomers (N,N'-dimethyl-1,3-propanediamine and N,N'-dimethyl-1,6-hexanediamine, respectively) through nucleophilic addition to the diglycidyl ester of dicarboxylic acid (diglycidyl adipate). Poly(amino alcohol ester) 1 and 2 were synthesized with a yield of 89% and 91% with Mn = 24,800 and Mn = 36,400, respectively. Poly(amino alcohol ester) 1 degraded hydrolytically in phosphate buffer at pH 7.4 with a half-life of approximately 5 days. Both polymers readily self-assembled with plasmid DNA into nanometer-sized DNA/polymer complexes less than 180 nm diameter and are significantly less cytotoxic than the commonly used DNA delivery polymer, poly(ethylene imine) (PEI).

Tuftsin: on the 30-year anniversary of Victor Najjar's discovery

After a short description of the results of Victor Najjar's research on tuftsin and of the discoveries done by other authors in the early stage of tuftsin investigation, the current state of work on tuftsin is presented, based mainly on the literature published in the years 1984-1997. The presentation follows this order: the occurrence of tuftsin and retro-tuftsin sequences in proteins, their synthesis and biology, the antigenic properties of tuftsin, its influence on phagocytic cells, and other biologic activities of tuftsin, including antimicrobial, antiviral, antitumor and central effects, and the search for tuftsin superactive analogs.

Quantitation of N,N,N',N'-tetrakis (2-hydroxypropyl)-ethylenediamine in plasma by gas chromatography

A wide-bore capillary gas chromatographic method with nitrogen-selective thermionic detection is described for the quantitative analysis of N,N,N',N'-tetrakis (2-hydroxypropyl)ethylenediamine (Quadrol) in plasma. N,N,N',N'-tetrakis (2-hydroxybutyl)ethylenediamine is used as an internal standard. Rat or human plasma samples (0.5 ml) are mixed with internal standard, adjusted to alkaline pH and subjected to a single extraction with dichloromethane. Quadrol recovery from plasma typically exceeds 90%. The method is linear over the range 1.0-50 micrograms/ml. The working detection limit is 0.5 microgram/ml and the analysis time is under 7 min. The procedure has been used to obtain plasma concentration versus time data for the evaluation of Quadrol pharmacokinetics in rats.

Resolution of diastereomers of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (quadrol) by reversed-phase high-performance liquid chromatography

Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, has been recently observed to display biological activity. It is an immunostimulant and has been implicated as a potentially useful agent in accelerated wound healing. Quadrol exists as a mixture of four unique diastereomers, each of which may, upon further investigation, display differences in biological activity. This paper describes an high-performance liquid chromatographic procedure (both analytical and prep) for the separation of the Quadrol diastereomers. Gas-liquid chromatography and NMR data are presented which corroborate the high-performance liquid chromatographic results. This procedure may be used to obtain pure Quadrol diastereomers, to monitor the progress of Quadrol synthesis from propylene oxide and ethylenediamine or to develop a quantitative assay for Quadrol diastereomers.

Promotion of wound collagen formation in normal and diabetic mice by quadrol

The rate of collagen deposition in implanted polytetrafluoroethylene (PTFE) tubing in non-diabetic and streptozotocin-induced (STZ) diabetic mice was measured during 14 days post-wounding. At the time of implantation, test groups received injections of either Quadrol [N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine], glucan, or buffer in an area adjacent to the wound site. The accumulation of collagen in the implants of Quadrol-treated non-diabetic animals was more than 200% above control on days 8 to 11 and was 50% above control on day 14. In Quadrol-treated STZ-diabetic mice, the collagen accumulation gradually increased from 50% above control on day 8 to 200% above control on day 14. Treatment with glucan increased the collagen accumulation in normal mice 200 to 300% above control from days 8 to 11 respectively and then 30% above control on day 14. Collagen accumulation in the implants of the glucan-treated STZ-diabetic mice was similar to the control group. These results indicate that Quadrol promotes in vivo collagen synthesis and that Quadrol may be effective as a stimulator of wound healing in diabetic and non-diabetic animals.

Investigation into the mechanism of stimulation of macrophages by Quadrol

Enhanced glucose utilization was observed in continuous cultures of macrophages in medium containing 4mM Quadrol, [N,N,N',N',Tetrakis(2-hydroxypropyl)ethylenediamine]. This enhancement was both time and concentration dependent. Radiolabeled 4mM Quadrol, after incubation with macrophages for 60 minutes, was shown to be associated with the cells at a level of 4 nmoles/10(6) cells. This association increased linearly with time, reaching a maximum at 60 minutes with no observable difference after 24 hours. Trypsin-EDTA treatment of these macrophages for 15 minutes reduced the amount of Quadrol associated with cells by about 50%. Quadrol, unlike Ca Ionophore A23187, did not induce influx of 45Ca into the cells within the incubation period of 60 minutes. Quadrol methacrylate and Poly(Quadrol methacrylate) stimulated macrophages to exhibit increased phagocytosis of polystyrene beads. This stimulation was comparable to that observed for Quadrol.