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PubMed2000

Slow polymerization of Mycobacterium tuberculosis FtsZ.

The essential cell division protein, FtsZ, from Mycobacterium tuberculosis has been expressed in Escherichia coli and purified. The recombinant protein has GTPase activity typical of tubulin and other FtsZs. FtsZ polymerization was studied using 90 degrees light scattering. The mycobacterial protein reaches maximum polymerization much more slowly ( approximately 10 min) than E. coli FtsZ. Depolymerization also occurs slowly, taking 1 h or longer under most conditions. Polymerization requires both Mg(2+) and GTP. The minimum concentration of FtsZ needed for polymerization is 3 microM. Electron microscopy shows that polymerized M. tuberculosis FtsZ consists of strands that associate to form ordered aggregates of parallel protofilaments. Ethyl 6-amino-2, 3-dihydro-4-phenyl-1H-pyrido[4,3-b][1,4]diazepin-8-ylcarbamate+ ++ (SRI 7614), an inhibitor of tubulin polymerization synthesized at Southern Research Institute, inhibits M. tuberculosis FtsZ polymerization, inhibits GTP hydrolysis, and reduces the number and sizes of FtsZ polymers.

Bacterial Proteins↗
PubMed1981

Inhibition of microtubule polymerization by the tubulin-colchicine complex: inhibition of spontaneous assembly.

The inhibition of microtubule polymerization by colchicine requires the formation of tubulin-colchicine complexes, and inhibition of polymerization is proportional to the concentration of tubulin-colchicine complexes rather than to the total concentration of colchicine. Because the formation of such complexes is slow relative to polymerization, the kinetics of complex formation obscure the kinetics of inhibition of polymerization. We have taken defined quantities of preformed tubulin-colchicine complexes, relying on their slow dissociation, and added these to microtubule protein, which was allowed to polymerize by temperature shift to 37 degrees C. The degree of polymerization was then determined by measurement of turbidity at 400 nm. An appropriate kinetic analysis allowed us to distinguish effects of inhibitor on initiation and elongation phase of polymerization, without resorting to the use of initiation inhibitors. The results are consistent with a reversible association of tubulin-colchicine complex with microtubule ends blocking further elongation (K1 = 0.16 micro M). Steady-state measurements suggest that copolymerization of tubulin-colchicine complex is a minor factor under the conditions used. By contrast, little inhibition of initiation was observed, possibly because tubulin-colchicine complex competes with the tubulin dimer, but not with the larger oligomers required for the initiation process.

Animals↗
PubMed1987

Kinetic and thermodynamic analysis of taxol-induced polymerization of purified tubulin.

The kinetic and thermodynamic behavior of in vitro taxol-induced polymerization of purified tubulin has been studied. The assembly of tubulin initiated by taxol has a critical concentration of 0.1 mg/mL at 37 degrees C and consists of two consecutive pseudo first-order processes, a fast phase followed by a slow phase. The rate constants of the fast and slow phase polymerizations increase linearly with increasing tubulin concentration. This implies that the polymerization is a true pseudo first-order process. The ln (l/t0.5) of polymerization for both fast and slow phases follows a linear function with ln [tubulin] fulfilling one of the criteria of condensation polymerization mechanism. From the Arrhenius plot, the temperature dependence of the rate of tubulin polymerization in the presence of taxol is biphasic. The apparent activation enthalpies for the overall polymerization reaction are 13.0 and 50.8 kcal/mol (1 cal = 4.1868 J), respectively, above and below 26 degrees C. The apparent activation enthalpies for the elongation reaction have also been determined. The values are 11.6 and 28.4 kcal/mol above and below 28 degrees C. The temperature dependence of the equilibrium constants as revealed by the van't Hoff plot is also biphasic. The standard enthalpy and entropy values are delta H degrees = 7.4 and 22.5 kcal/mol above and below 30 degrees C, and delta S degrees = 50.3 and 101.0 cal/(deg.mol), at high and low temperatures, respectively. This suggests that the taxol-induced assembly of purified tubulin is a process driven by the effect of entropy.

Alkaloids↗
PubMed2004

Activation of the Arp2/3 complex by N-WASp is required for actin polymerization and contraction in smooth muscle.

Contractile stimulation has been shown to initiate actin polymerization in smooth muscle tissues, and this actin polymerization is required for active tension development. We evaluated whether neuronal Wiskott-Aldrich syndrome protein (N-WASp)-mediated activation of the actin-related proteins 2 and 3 (Arp2/3) complex regulates actin polymerization and tension development initiated by muscarinic stimulation in canine tracheal smooth muscle tissues. In vitro, the COOH-terminal CA domain of N-WASp acts as an inhibitor of N-WASp-mediated actin polymerization; whereas the COOH-terminal VCA domain of N-WASp is constitutively active and is sufficient by itself to catalyze actin polymerization. Plasmids encoding EGFP-tagged wild-type N-WASp, the N-WASp VCA and CA domains, or enhanced green fluorescent protein (EGFP) were introduced into tracheal smooth muscle strips by reversible permeabilization, and the tissues were incubated for 2 days to allow for expression of the proteins. Expression of the CA domain inhibited actin polymerization and tension development in response to ACh, whereas expression of the wild-type N-WASp, the VCA domain, or EGFP did not. The increase in myosin light-chain (MLC) phosphorylation in response to contractile stimulation was not affected by expression of either the CA or VCA domain of N-WASp. Stimulation of the tissues with ACh increased the association of the Arp2/3 complex with N-WASp, and this association was inhibited by expression of the CA domain. The results demonstrate that 1) N-WASp-mediated activation of the Arp2/3 complex is necessary for actin polymerization and tension development in response to muscarinic stimulation in tracheal smooth muscle and 2) these effects are independent of the regulation of MLC phosphorylation.

Acetylcholine↗
PubMed2004

Electron microscopic study of actin polymerization in airway smooth muscle.

Actin polymerization as part of the normal smooth muscle response to various stimuli has been reported. The actin dynamics are believed to be necessary for cytoskeletal remodeling in smooth muscle in its adaptation to external stress and strain and for maintenance of optimal contractility. We have shown in our previous studies in airway smooth muscle that myosins polymerized in response to contractile activation as well as to adaptation at longer cell lengths. We postulated that the same response could be elicited from actins under the same conditions. In the present study, actin filament formation was quantified electron microscopically in cell cross sections. Nanometer resolution allowed us to examine regional distribution of filaments in a cell cross section. Airway smooth muscle bundles were fixed in relaxed and activated states at two lengths; muscle preparations were also fixed after a period of oscillatory strain, a condition known to cause depolymerization of myosin filaments. The results indicate that contractile activation and increased cell length nonsynergistically enhanced actin polymerization; the extent of actin polymerization was substantially less than that of myosin polymerization. Oscillatory strain increased thin filament formation. Although thin filament density was found higher in cytoplasmic areas near dense bodies, contractile activation did not preferentially enhance actin polymerization in these areas. It is concluded that actin thin filaments are dynamic structures whose length and number are regulated by the cell in response to changes in extracellular environment and that polymerization and depolymerization of thin filaments occur uniformly across the whole cell cross section.

Actin Cytoskeleton↗
PubMed1997

Natural osmolyte trimethylamine N-oxide stimulates tubulin polymerization and reverses urea inhibition.

The natural osmolyte trimethylamine N-oxide (TMAO) is one of the methylamine compounds often accumulated by diverse organisms in response to osmotic stress and/or to compensate for the deleterious effects of urea. Tubulin polymerization is promoted by TMAO. At 1 M TMAO, tubulin polymers are produced with properties expected of normal steady-state microtubules (MT): polymerization is reversed by exposure to cold or the antimitotic drug podophyllotoxin, a critical concentration for polymerization at 30 degrees C of 1.5 microM is found, and the morphology of the polymers in electron micrographs is typical of MT and ribbons, or open MT. At 2 M TMAO, polymerization is very rapid and hyperstable polymers are formed. These are resistant to cold-induced depolymerization although still sensitive to podophyllotoxin inhibition. A lower critical concentration of 0.7 microM is observed, and electron micrographs reveal MT, ribbons, and other polymer forms not usually stable, such as splayed protofilaments. Inhibition of tubulin polymerization by low concentrations of urea (Sackett, D. L., B. Bhattacharyya, and J. wolff. Biochemistry 33: 12868-12878, 1994) is largely reversed by the presence of TMAO at one-half the molarity of urea, the physiological ratio observed in cartilaginous fishes. Other methylamines, including betaine, dimethylglycine, glycine, and sarcosine, failed to stimulate MT polymerization or protect against urea inhibition. Trimethylamine, taurine and glycylglycine inhibit polymerization. TMAO did not interfere with binding of MT-associated proteins (MAP) and protected both tubulin assembly and MAP binding from urea.

Animals↗
PubMedDate not supplied

Semi-elemental formula or polymeric formula: is there a better choice for enteral nutrition in acute pancreatitis? Randomized comparative study.

BACKGROUND: Jejunal nutrition is recommended during acute pancreatitis. The use of semi-elemental formulas presents several theoretical advantages over polymeric formulas, but their clinical value has been poorly documented. Our aim was to evaluate in patients with acute pancreatitis the effect of enteral nutrition by a semi-elemental formula compared with a polymeric formula. METHODS: A randomized prospective pilot study, stratified according to severity, was performed in 30 consecutive patients with acute pancreatitis requiring jejunal nutrition. The semi-elemental group received 35 kcal/kg/d of Peptamen (n = 15), and the polymeric group received the same quantity of Sondalis-Iso (n = 15). Tolerance was evaluated after 7 days of enteral nutrition (D7) on visual analog scale (VAS), stool frequency, and 24-hour steatorrhea/creatorrhea. Outcome was evaluated by weight loss, length of hospital stay, and infection rate. RESULTS: Results were calculated as mean +/- SEM, t-test, or chi2. Patients of the 2 groups were comparable in terms of age, gender, and severity. Tolerance was good in both groups (semi-elemental vs polymeric: VAS, 7.4 +/- 0.6 vs 7.1 +/- 0.6, not significant (NS); number of stools per 24 hours, 1.7 +/- 0.4 vs 1.8 +/- 0.4, NS). Steatorrhea and creatorrhea were lower than normal in both groups. In semi-elemental group, the length of hospital stay was shorter (23 +/- 2 vs 27 +/- 1, p = .006) and weight loss was less marked (1 +/- 1 vs 2 +/- 0, p = .01). One patient in semi-elemental group and 3 patients in polymeric group developed an infection (NS). CONCLUSIONS: Semi-elemental and polymeric nutrition are very well tolerated in patients with acute pancreatitis. Nutrition with a semi-elemental formula supports the hypothesis of a more favorable clinical course than nutrition with a polymeric formula, but this conclusion needs to be established in larger adequately powered clinical trials.

Adult↗
PubMed2004

Cytotoxicity of eluates from a gamma-ray-polymerized poly(methyl methacrylate).

The purpose of this study was to evaluate the cytotoxicity of gamma-ray-polymerized poly(methyl methacrylate) (PMMA). A total of 32 disk-shaped PMMA specimens were polymerized by gamma-irradiation with 1 Mrad for 4 h (Group 1), 2 Mrad for 8 h (Group 2), 3 Mrad for 12 h (Group 3), and thermally polymerized (Group 4). Four- and 6-day eluates of the specimens were prepared in Eagle's Minimal Essential Medium (EMEM) without Fetal Calf Serum (FCS). The eluates and EMEM supplemented by 20% FCS were placed into Vero (green African monkey kidney) cell cultures, and incubated at 37 degrees C for 24, 48, and 72 h. EMEM kept at 37 degrees C for 4 and 6 days was also tested up to 72 h, and served as controls. After each incubation period, the number of viable cells were counted and stained at the termination of the experiments for histological evaluation. The number of viable cells for Group 1 was slightly lower than that of other groups after 24 h. The time-dependent increase in cells exposed to Group 3 eluates was comparable with the control group. There was a dose-dependent effect on cell response for gamma-ray-polymerized specimens. The number of viable cells and the morphological appearance of cells in all groups were similar. Eluates from PMMA polymerized by low doses of gamma-ray with reduced polymerization periods have early inhibitory effects on cell response. Higher doses of gamma-irradiation lead to better cellular response, and therefore, may be future candidates for polymerization of PMMA.

Animals↗
PubMed1988

Soluble and polymerized tubulin levels in the anterior pituitary lobe of the lactating rat during suckling.

A [3H]colchicine-binding assay was employed for estimating the relative amounts of soluble and polymerized tubulin present in an individual anterior pituitary lobe. Colchicine binding to these two tubulin pools was time dependent and dose responsive. Scatchard analysis of the binding revealed that [3H]colchicine bound to both fractions with similar affinity. After establishing the optimal conditions for the binding assay, the effect of suckling on the relative levels of the two tubulin pools was studied. Groups of primiparous rats on days 12-14 postpartum were isolated from their pups for 4-5 h, then suckled for 30, 60, and 90 min, and killed, and the anterior pituitary lobes were dissected out. Each pituitary lobe was processed to obtain the two tubulin pools, viz. soluble and polymerized tubulin fractions. Suckling for 30 min resulted in an increase in soluble tubulin levels and a concomitant decrease in the polymerized pools. At 60 and 90 min, the soluble tubulin levels gradually decreased to presuckled levels, whereas the polymerized pools increased from the 30-min levels to those observed at 0 min. In another experiment, suckling for 10 min resulted in a decrease in the soluble tubulin levels and a corresponding increase in the polymerized tubulin pool. Treatment of nonsuckled rats with domperidone for 10 min also resulted in a shift of the equilibrium between the two tubulin pools similar to that observed at 10 min of suckling. Administration of bromocriptine 30 min beforehand to nonsuckled rats and then suckling them for 10 min blocked the suckling-induced rise in the polymerized tubulin levels. These results suggest a regulatory role for dopamine in the suckling-induced shift in the equilibrium between the soluble and polymerized tubulin pools in the anterior pituitary lobe.

Animals↗
PubMed2001

In-vitro and in-vivo evaluation of pH-responsive polymeric micelles in a photodynamic cancer therapy model.

pH-sensitive polymeric micelles of randomly and terminally alkylated N-isopropylacrylamide copolymers were prepared and characterized. Aluminium chloride phthalocyanine (AlClPc), a second generation sensitizer for the photodynamic therapy of cancer, was incorporated in the micelles by dialysis. Their photodynamic activities were evaluated in-vitro against EMT-6 mouse mammary tumour cells and in-vivo against EMT-6 tumours implanted intradermally on each hind thigh of Balb/c mice. pH-sensitive polymeric micelles were found to exhibit greater cytotoxicity in-vitro than control Cremophor EL formulations. In the presence of chloroquine, a weak base that raises the internal pH of acidic organelles, in-vitro experiments demonstrated the importance of endosomalllysosomal acidity for the pH-sensitive polymeric micelles to be fully effective. Biodistribution was assessed by fluorescence of tissue extracts after intravenous injection of 2 micromol kg(-1) AlClPc. The results revealed accumulation of AlClPc polymeric micelles in the liver, spleen and lungs, with a lower tumour uptake than AlClPc Cremophor EL formulations. However, polymeric micelles exhibited similar activity in-vivo to the control Cremophor EL formulations, demonstrating the higher potency of AlClPc polymeric micelles when localized in tumour tissue. It was concluded that polymeric micelles represent a good alternative to Cremophor EL preparations for the vectorization of hydrophobic drugs.

Acrylamides↗
PubMed2002

Synthesis and properties of a naproxen polymeric prodrug.

A water-soluble polymeric prodrug containing a naproxen moiety was synthesized. The carboxylic groups of naproxen were condensed with the hydroxyl groups of 2-hydroxyethyl methacrylate (HEMA) to produce a drug-linked monomer, denoted HN. The polymeric prodrug was prepared by copolymerization of HN with methacrylic acid. The molar percentage of HN in the polymeric prodrug was 26 mol%, as determined by 1H NMR. To investigate the pertinence of this polymeric prodrug, the hydrolysis was studied in-vitro with or without esterase or lipase. The kinetics of enzymatic catalysis was calculated from a Lineweaver-Burk plot. The anti-inflammatory activity was evaluated using the carrageenan-induced oedema test. The polymeric prodrug released a major fraction of the free naproxen and a significant fraction of the hydroxyethyl ester derived-naproxen. The maximum hydrolysis rate Vmax, and the Michaelis constant Km were calculated to be 2.16 x 10(-5) equiv. mol L-1 min-1 and 5.11 x 10(-2) equiv. mol L-1. The maximum anti-inflammatory inhibition of free naproxen appeared at 2 h and quickly decreased thereafter. In contrast, the polymeric prodrug showed a maximum at around 2-3 h and then slowly decreased. This indicates that the polymeric prodrug displays greater potency than free naproxen in the inhibition of acute inflammatory processes over long periods.

Animals↗
PubMed2005

Regulation of cortactin/dynamin interaction by actin polymerization during the fission of clathrin-coated pits.

Separation of clathrin-coated pits from the plasma membrane, a key event during endocytosis, is thought to be driven by dynamin and the actin cytoskeleton. However, the mechanism for the actin-mediated endocytosis remains elusive. RNA interference-mediated suppression of cortactin, an F-actin binding protein that promotes Arp2/3 complex-mediated actin polymerization, effectively blocked transferrin uptake. Depletion of cortactin in brain cytosol inhibited formation of clathrin-coated vesicles by 70% as analyzed in a cell-free system. Interestingly, the interaction between cortactin and dynamin 2 in cells was dependent on actin polymerization and was attenuated upon cell exposure to cytochalasin D as analyzed by immunofluorescence and immunoprecipitation. Moreover, a cortactin mutant deficient in Arp2/3 binding colocalized less efficiently with dynamin 2 and inhibited the uptake of transferrin. The effect of actin polymerization on the interaction between cortactin and the dynamin proline-rich domain (PRD) was further evaluated under a condition for actin polymerization in vitro. Cortactin binds to the dynamin PRD with an equilibrium dissociation constant of 81 nM in the presence of the Arp2/3 complex and actin, and 617 nM in the absence of actin polymerization. Taken together, these data demonstrate that Arp2/3-mediated actin polymerization regulates the accessibility of cortactin to dynamin 2 and imply a novel mechanism by which cortactin and dynamin drive the fission of clathrin-coated pits in an actin polymerization dependent manner.

Actin Cytoskeleton↗
PubMed2002

Synthesis of water-soluble polymeric prodrugs possessing 4-methylcatechol derivatives by mechanochemical solid-state copolymerization and nature of drug release.

In this study we synthesized the water-soluble polymeric prodrugs possessing a 4-methylcatechol (4MC) derivative as a side chain by mechanochemical solid-state copolymerization. 1-benzoyl-4-methylcatechol (Bz4MC) was selected as a model compound of 4MC, and its methacryloyl derivative (1) was synthesized. 6-O-methacryloyl-D-galactose (2) was also prepared as a water-soluble monomer. The mechanochemical solid-state copolymerization of 1 and 2 was carried out to obtain the water-soluble polymeric prodrug possessing the Bz4MC as a side chain. The mechanochemical copolymerization of 1 and 2 proceeded to completion, and the polymeric prodrug produced possessed a narrow molecular weight distribution. Three kinds of polymeric prodrugs, whose compositions were different from one another, were hydrolyzed in vitro. The hydrolysis of these polymeric prodrugs proceeded to completion. The rate constants of hydrolysis decreased with increasing the mole fraction of 1 in polymeric prodrug. It was suggested that the rate constant of hydrolysis could be controlled by the composition, the mole fraction of 1 in the polymeric prodrug.

Catechols↗
PubMed2000

Assessing the effect of composite formulation on polymerization stress.

BACKGROUND: In this study, the authors measured the magnitude of the polymerization stress of a variety of dental composite materials and explored the effect of a novel monomer, a methacrylated derivative of styrene-allyl alcohol, or MSAA, in reducing polymerization stress. METHODS: Eleven commercially available composites and a series of experimental composites were evaluated in a mechanical testing machine to measure the maximum stress generated during placement in a confined setting. RESULTS: A significant relationship between higher filler volume and increased polymerization stress was found among the commercial materials. Introduction of MSAA produced a 30 percent reduction in polymerization stress in an experimental composite material. CONCLUSIONS: Composites that contain lower levels of inorganic filler particles are less likely to produce high levels of polymerization stress during placement. Modifications to traditional composite chemistry can result in materials that produce lower polymerization stress levels. CLINICAL IMPLICATIONS: The polymerization stress produced by dental composite materials during light-curing is a leading reason for bond failures in adhesive restorations, resulting in postoperative sensitivity, marginal staining and recurrent caries.

Analysis of Variance↗
PubMed2006

Phospholipid vesicle fusion on micropatterned polymeric bilayer substrates.

As an approach to create versatile model systems of the biological membrane we have recently developed a novel micropatterning strategy of substrate-supported planar lipid bilayers (SPBs) based on photolithographic polymerization of a diacetylene phospholipid, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine. The micropatterned SPBs are composed of a polymeric bilayer matrix and embedded fluid lipid bilayers. In this study, we investigated the incorporation of fluid bilayers into micropatterned polymeric bilayer matrices through the adsorption and reorganization of phospholipid vesicles (vesicle fusion). Total internal reflection fluorescence microscopy observation showed that vesicle fusion started at the boundary of polymeric bilayers and propagated into the central part of lipid-free regions. On the other hand, quartz crystal microbalance with dissipation monitoring revealed that the transformation from adsorbed vesicles into SPBs was significantly accelerated for substrates with micropatterned polymeric bilayers. These results indicate that the edges of polymeric bilayers catalyze the formation of SPBs by destabilizing adsorbed vesicles and also support the premise that polymeric bilayers and embedded fluid bilayers are forming a continuous hybrid bilayer membrane, sealing energetically unfavorable bilayer edges.

Biomimetics↗
PubMed2006

Analysis of the microtensile bond strength to enamel of two adhesive systems polymerized by halogen light or LED.

With the development of composite resin polymerization techniques, LEDs were introduced to the market place. Based on the studied literature, the aim of this study was to evaluate, through microtensile testing, the bond strength to enamel of a composite resin associated to a conventional (multi-bottle) adhesive system or to a self etching primer adhesive system, polymerized by halogen light or LED (light emitting diode). Bovine teeth were divided into 4 groups with 10 teeth each (n = 10). Then the adhesives Scotchbond Multipurpose Plus (3M-ESPE) and Clearfil SE Bond (Kuraray) were applied following the manufacturers instructions. Both systems were polymerized for 10 s by halogen light (Degulux Soft Start-Degussa Hulls) set at 550 mW/cm(2) or by LED (Kerr Demetron) set at 600 mW/cm(2). The composite resin Filtek Z-250 was applied in four 1 mm increments with the aid of a square, condensation silicon, 5 mm x 5 mm matrix, and polymerized by either of light sources for 40 s. Scotchbond Multipurpose Plus polymerized by halogen light presented the highest bond strength values (39.69 +/- 7.07 MPa), and the other groups did not present statistically significant differences: Scotchbond Multipurpose Plus polymerized by LED (22.28 +/- 2.63 MPa), Clearfil SE Bond polymerized by halogen light (27.82 +/- 2.65 MPa) and by LED (22.89 +/- 5.09 MPa).

Adhesiveness↗
PubMed2003

Polymeric micelles for delivery of poorly water-soluble compounds.

Amphiphilic polymers assemble into nanoscopic supramolecular core-shell structures, termed polymeric micelles, which are under extensive study for drug delivery. There are several reasons for this growing interest. Polymeric micelles maybe safe for parenteral administration relative to existing solubilizing agents (for instance, Cremophor EL), permitting an increase in the dose of potent yet toxic and poorly water soluble compounds. Polymeric micelles solubilize important poorly water-soluble compounds, such as amphotericin B (AmB), propofol, paclitaxel, and photosensitizers. A major factor in drug solubilization is the compatibility of a drug and a core of a polymeric micelle. In this context, we may consider Pluronics, poly(ethylene glycol) (PEG)-phospholipid conjugates, PEG-b-poly(ester)s, and PEG-b-poly(L-amino acid)s for drug delivery. Polymeric micelles may circulate for prolonged periods in blood, evade host defenses, and gradually release drug. Thus, they may show a preferential accumulation at sites of disease such as solid tumors. Polymeric micelles inhibit p-glycoprotein at drug-resistant tumors, gastrointestinal tract, and blood/brain barrier, perhaps providing a way to overcome drug resistance in cancer and increase drug absorption from the gut and drug absorption into the brain. Lastly, polymeric micelles may reduce the self-aggregation of polyene antibiotics, key membrane-acting drugs used to combat life-threatening systemic fungal diseases. In this way, they may reduce its dose-limiting toxicity without a loss of antifungal activity.

Drug Stability↗
PubMed1994

Clinical evaluation of a semipermeable polymeric membrane dressing for the treatment of chronic diabetic foot ulcers.

OBJECTIVE: To evaluate the utility of a semipermeable polymeric membrane dressing for the treatment of chronic diabetic foot ulcers. RESEARCH DESIGN AND METHODS: Nineteen subjects with either insulin-dependent diabetes mellitus (IDDM) or non-insulin-dependent diabetes mellitus (NIDDM) and foot ulcers were randomly assigned to the polymeric dressing or conventional wet-to-dry saline dressings. Subjects had foot ulcer site measurements performed every 3 weeks. The subjects using conventional therapy were allowed to cross over to polymeric dressing after 2 months. RESULTS: At the end of 2 months, in the patients using the polymeric dressing, ulcer size was reduced to 35 +/- 16% of baseline. The patients on conventional therapy had an ulcer size of 105 +/- 28% of baseline (P < 0.03, polymeric vs. conventional). Patients initially treated with wet-to-dry saline were crossed over into the polymeric membrane treatment and demonstrated a decrease to 35 +/- 11% of baseline size (p < 0.02) after an additional 2 months. CONCLUSIONS: The semipermeable polymeric membrane dressing is a useful therapeutic option for treating uncomplicated chronic diabetic foot ulcers.

Chronic Disease↗