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PubMedDate not supplied

Primary amino-terminal heterobifunctional poly(ethylene oxide). Facile synthesis of poly(ethylene oxide) with a primary amino group at one end and a hydroxyl group at the other end.

Well-defined poly(ethylene oxide) (PEO) with a cyano group at one end and a hydroxyl group at the other terminus was synthesized by the anionic ring opening polymerization of ethylene oxide (EO) initiated with (cyanomethyl)potassium (CMP) which was prepared by the metalation reaction of acetonitrile with potassium naphthalene in THF. Primary amino-terminal heterotelechelic PEO was obtained by the reduction of the cyano group at the end of the polymer chain by lithium aluminum hydride.

Acetonitriles↗
PubMedDate not supplied

Tensides from the group of propylene oxide and ethylene oxide copolymers. Part XI. Solubilization of acetylsalicylic acid (ASA) by monomethoxypoly(ethylene glycol) (M-PEG) micelles.

The process of structural solubilization of acetyl salicylic acid (ASA) in a balanced system (weight-balanced) by micelles of monomethoxypoly(ethylene glycol)-s-CH3OCH2[CH2OCH2]n-CH2OH (M(r) = 350-5000) types and, for comparison, by those of F-68 and F-108 Pluronics, was investigated. The determined viscosity and hydrodynamic parameters ([eta], KH, M eta, Robs, omega) allowed for the calculation of solubilizing activity of monomethoxypoly(ethylene glycol) micelles-pi s(ASA). The results of the investigation point at monomethoxypoly(ethylene glycol)s as an excipient, which may help to obtain new drug delivery systems.

Aspirin↗
PubMed1996

Comparison of ion plasma, vaporized hydrogen peroxide, and 100% ethylene oxide sterilizers to the 12/88 ethylene oxide gas sterilizer.

OBJECTIVE: The performance of a standard gas sterilizer, which uses a mixture of 12% ethylene oxide (EtO) and 88% chlorofluorocarbon as the sterilizing gas (12/88), was compared to selected gas, ion plasma, and vaporized hydrogen peroxide (H2O2) sterilizers that do not use chlorofluorocarbons. The effect of serum and salt on sterilizer performance was evaluated. DESIGN: Test carriers (porcelain and stainless steel penicylinders, or 125-cm lengths of plastic tubing [internal diameter of 3.2 mm]) were inoculated with Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Mycobacterium chelonei, Bacillus stearothermophilus spores, Bacillus subtilis spores, and Bacillus circulans spores and then subjected to sterilization using 12/88, 100% EtO, ion plasma, or vaporized H2O2. The bacterial inoculum was prepared with and without 10% serum and 0.65% salt, and the residual bacterial load after sterilization as determined using viable counts. RESULTS: All of the sterilizers tested effected a six-log10 reduction of the bacterial inoculum on penicylinders, unless 10% serum and 0.65% salt were present, in which case the 100% EtO, vaporized H2O2, and ion plasma sterilizers were not as effective as the 12/88 sterilizer. None of the sterilizers could eradicate 10(6) CFU of all of the bacteria in 10% serum and 0.65% salt when inoculated inside a narrow lumen. CONCLUSIONS: The margin of safety for the 100% EtO, vaporized H2O2, and ion plasma sterilizers is less than that of the 12/88 sterilizer. The inability of all sterilizers, including the 12/88, to kill organisms in narrow lumens reliably when serum and salt were present raises concern about the current practice of gas sterilization of flexible endoscopes.

Analysis of Variance↗
PubMed1998

Ambient and biochemical effect monitoring of workers exposed to ethylene oxide.

OBJECTIVES: Ethylene oxide is an alkylating agent known to be a directly acting mutagen and carcinogen. This study describes the relationship between workplace ambient air concentrations of ethylene oxide and the concentration of N-2-hydroxyethylvaline in the globin of exposed workers. METHODS: During the sterilization of medical equipment, 12 workers were occupationally exposed to ethylene oxide. Personal and stationary ambient air measurements were carried out to monitor the external exposure. The determination of the protein adducts was based on the N-alkyl-Edman method, introducing a new commercially available dipeptide standard for calibration purposes. RESULTS: Ethylene oxide concentrations ranging from 0.2 to 8.5 ppm were found in the workplace air. The adduct concentrations ranged from 5,219 to 32,738 pmol N-2-hydroxyethylvaline/g globin in the case of regularly exposed workers (n = 9) and from 518 to 3,321 pmol N-2-hydroxyethylvaline/g globin for three persons with occasional contact with ethylene oxide. CONCLUSIONS: The Deutsche Forschungsgemeinschaft established in 1993 a relationship between the ethylene oxide concentration in ambient air and the amount of N-2-hydroxyethylvaline in human globin. By extrapolation, constant exposure to 1 ppm ethylene oxide should yield approximately 4,000 pmol N-2-hydroxyethylvaline/g globin. The ambient air concentrations of ethylene oxide and the amount of N-2-hydroxyethylvaline determined within the present study confirm this extrapolation in practice. In addition, the determination of adducts based on the use of commercially available dipeptide standards for calibration purposes turned out to be an advantageous alternative to the commonly used protein standards.

Air Pollution, Indoor↗
PubMedDate not supplied

Redox reaction of poly(ethylene oxide)-modified hemoglobin in poly(ethylene oxide) oligomers at 120 degrees C.

Human hemoglobin, modified with poly(ethylene oxide) with average molecular weight of 3500 (PEO-Hb) was dissolved in PEO200 (molecular weight of 200) containing 0.5 M KCl. A quasi-reversible redox reaction of the PEO-Hb was found in PEO oligomers by alternatingly changing the potential polarity (+/- 1.2 V vs Ag). The PEO-Hb showed redox reactions in PEO200 even at 120 degrees C. PEO modification was concluded to give the thermal stability in some extent. In phosphate buffer at 70 degrees C, the electrochemical redox reaction of native Hb was not observed spectroscopically, but that of PEO-Hb was detected. The most effective factor was, however, concluded to be the use of PEO oligomers as a solvent. The molecular motion of PEO oligomers should be milder than that of water at higher temperature. This lower molecular motion was suggested to keep the redox activity of PEO-Hb in the PEO oligomer at 120 degrees C. However, the PEO-Hb in PEO200 was stable in the oxidized form at 30 degrees C; it was reduced without giving potential at 120 degrees C. Cyclic voltammetry revealed that this autoreduction was attributed to the shift of redox potential with elevating temperature.

Electrochemistry↗
PubMed2006

Dynamic and static light scattering studies on self-aggregation behavior of biodegradable amphiphilic poly(ethylene oxide)-poly[(R)-3-hydroxybutyrate]-poly(ethylene oxide) triblock copolymers in aqueous solution.

The self-aggregation behavior of two amphiphilic poly(ethylene oxide)-poly[(R)-3-hydroxybutyrate]-poly(ethylene oxide) (PEO-PHB-PEO) triblock copolymer samples with nearly identical PHB block lengths but different PEO block lengths, PEO-PHB-PEO(2000-810-2000) and PEO-PHB-PEO(5000-780-5000), was studied with dynamic and static light scattering (DLS and SLS), in combination with fluorescence spectroscopy and transmission electron microscopy (TEM). The formation of polymeric micelles by the two PEO-PHB-PEO triblock copolymers was confirmed with fluorescence technique and TEM. DLS analysis showed that the hydrodynamic radius (R(h)) of the monodistributed polymeric micelles increased with an increase in PEO block length. The relative thermostability of the triblock copolymer micelles was studied by SLS and DLS at different temperatures. The aggregation number and the ratio of the radius of gyration over hydrodynamic radius were found to be independent of temperature, probably due to the strong hydrophobicity of the PHB block. The combination of DLS and SLS studies indicated that the polymeric micelles were composed of a densely packed core of hydrophobic PHB blocks and a corona shell formed by hydrophilic PEO blocks. The aggregation numbers were found to be approximately 53 for PEO-PHB-PEO(2000-810-2000) micelles and approximately 37 for PEO-PHB-PEO(5000-780-5000) micelles. The morphology of PEO-PHB-PEO spherical micelles determined by DLS and SLS measurements was further confirmed by TEM.

Biocompatible Materials↗
PubMed1981

[Carcinogenic activity of ethylene oxide and its reaction products 2-chloroethanol, 2-bromoethanol, ethylene glycol and diethylene glycol. I. Carcinogenicity of ethylene oxide in comparison with 1,2-propylene oxide after subcutaneous administration in mice (author's transl)].

Ethylene oxide is an important initial product for a number of organic compounds and, in addition, is used in the medical field for sterilization. The aim of our experiments was to test ethylene oxide and, as a comparative substance, 1,2-propylene oxide in respect to their cancerogenic effectiveness in animal experiments. Ethylene oxide was administered subcutaneously in three dosages (1.0; 0.3 and 0.1 mg single dosage per mouse) once per week to groups of 100 female NMRI mice respectively. In the case of 1,2-propylene oxide, four dosages were used (2.5; 1.0; 0.3 and 0.1 mg single dosage per mouse). The vehicle was tricaprylin. Administrations were carried out over a period of 95 weeks. The mean total dosage per mouse in the case of ethylene oxide amounted to 64.4; 22.7, and 7.3 mg and, in the case of propylene oxide, to 165.4; 72.8; 21.7 and 6.8 mg. Both substances induced local tumours depending upon the dosage. There were mostly fibrosarcomas. In the case of the groups treated with ethylene oxide the frequency was between 11 and 5% and in the case of the groups treated with 1,2-propylene oxide this was between 16 and 2%. The cancerogenic effect of ethylene oxide and 1,2-propylene oxide determined in animal experiments could, therefore, be confirmed statistically. On the basis of the results presented in this paper, new aspects have arisen for the medical evaluation of ethylene oxide residues in the field of manufacturing and use and in respect to the TLV.

Animals↗
PubMed1990

[Tensides from a group of propylene oxide and ethylene oxide copolymers. VII. Test of utilizing critical concentrations of micella (CMC), at levels of equal density hydro-lipophilic (HLB) and measures of macroparticles (Ro, omega) in bile "A" of healthy persons and patients].

Using the model systems of reference (nonionic surfactants of Pluronic and Rokopol type) bile "A" in healthy and ill subjects (cholelithiasis, states after cholecystectomy, catarrh, chronic duodenitis) was characterized using chosen viscosity parameters. The model experiments enable selective, preclinical estimation of solubilisation capacity of nonionic surfactants of Pluronic type and their Polish analogues Rokopols.

Adult↗
PubMed1991

Mortality among workers exposed to ethylene oxide.

BACKGROUND: Ethylene oxide is a sterilant gas that causes leukemia and other cancers in animals. Studies in Sweden have shown an excess of leukemia and stomach cancer in humans exposed to ethylene oxide, but other studies have generally failed to confirm these findings. METHODS: We conducted a study of mortality in 18,254 U.S. workers exposed to ethylene oxide at 14 plants producing sterilized medical supplies and spices. The subjects averaged 4.9 years of exposure to the gas and 16 years of follow-up. The exposure levels in recent years averaged 4.3 ppm (eight-hour time-weighted adjusted exposure) for sterilizer operators and 2.0 ppm for other workers. The levels in earlier years are likely to have been several times higher. Mortality in this cohort was compared with that in the general U.S. population. RESULTS: Overall there was no significant increase in mortality from any cause in the study cohort. The standardized mortality ratios (SMRs) were 0.97 for leukemia (95 percent confidence interval, 0.52 to 1.67; 13 deaths observed), 1.06 for all hematopoietic cancers (95 percent confidence interval, 0.75 to 1.47; 36 deaths), and 0.94 for stomach cancer (95 percent confidence interval, 0.45 to 1.70; 11 deaths). Analyses according to job category and according to the duration of exposure showed no excess in cancers, as compared with the rate in the general population, but there was a significant trend toward increased mortality with increasing lengths of time since the first exposure for all hematopoietic cancers. The rate of death from hematopoietic cancer (especially non-Hodgkin's lymphoma) was significantly increased among men (SMR, 1.55; 27 deaths). Mortality from leukemia in recent years (1985 through 1987) was significantly increased among men (SMR, 3.45; 5 deaths). CONCLUSIONS: For the entire cohort, there was no increase in mortality from hematopoietic cancer. There was a slight but significant increase among men, however. Among men and women combined, there was a trend toward an increased risk of death from hematopoietic cancer with increasing lengths of time since the first exposure to ethylene oxide.

Cohort Studies↗
PubMed1998

Oncogene and suppressor gene expression as a biomarker for ethylene oxide exposure.

Ethylene oxide is a proven genotoxic chemical, and there is lots of evidence suggesting its carcinogenic effects in humans. The unexpected massive appearance of a certain tumorous cluster in personnel exposed to ethylene oxide in a Hungarian county hospital focused attention on the effects of this toxic gas. Since we had developed an animal model for the investigation of alterations in onco/suppressor gene expression due to external carcinogenic agents, and this model had already been used to evaluate the carcinogenic effects of cytostatic drugs in humans, an analysis of the effects of ethylene oxide exposure seemed to offer further information on the usefulness of gene expression as a biomarker. The main purpose of our study was to determine whether or not ethylene oxide exposure causes an elevated expression of onco/suppressor genes in the white blood cells of exposed people. Two different exposed groups and one control group were included in the study. The N-ras and p53 genes were chosen for the investigations of gene expression. N-ras is known to be activated in several tumor types, and p53 is also involved in carcinogenesis and plays an important role in the cellular answer mechanism to exogenous toxic effects. RNA was isolated from the white blood cells, slot blotted onto nitrocellulose membranes, and hybridized with chemoluminescently labeled gene probes. The results were detected on X-ray films and scanned into a computer, and relative risk for elevated gene expression was calculated in each group. Elevated N-ras and detectable p53 expressions were observed more frequently in both exposed groups compared with the control group (relative risks--N-ras: 1.57 [0.77-3.22] and 2.34 [1.21-4.52]; p53: 6.67 [2.35-18.92] and 6.06 [2.10-17.49]).

Biomarkers, Tumor↗
PubMed2006

pH responsiveness of dendrimer-like poly(ethylene oxide)s.

Poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA), two polymers known to form pH-sensitive aggregates through noncovalent interactions, were assembled in purposely designed architecture -a dendrimer-like PEO scaffold carrying short inner PAA chains-to produce unimolecular systems that exhibit pH responsiveness. Because of the particular placement of the PAA chains within the dendrimer-like structure, intermolecular complexation between acrylic acid (AA) and ethylene oxide (EO) units-and thus macroscopic aggregation or even mesoscopic micellization-could be avoided in favor of the sole intramolecular complexation. The sensitivity of such interactions to pH was exploited to generate dendrimer-like PEOs that reversibly shrink and expand with the pH. Such PAA-carrying dendrimer-like PEOs were synthesized in two main steps. First, a fifth-generation dendrimer-like PEO was obtained by combining anionic ring-opening polymerization (AROP) of ethylene oxide from a tris-hydroxylated core and selective branching reactions of PEO chain ends. To this end, an AB(2)C-type branching agent was designed: the latter includes a chloromethyl (A) group for its covalent attachment to the arm ends, two geminal hydroxyls (B(2)) protected in the form of a ketal ring for the growth of subsequent PEO generations by AROP, and a vinylic (C) double bonds for further functionalization of the interior of dendrimer-like PEOs. Reiteration of AROP and derivatization of PEO branches allowed us to prepare a dendrimer-like PEO of fourth generation with a total molar mass of 52,000 g x mol(-1), containing 24 external hydroxyl functions and 21 inner vinylic groups in the interior. A fifth generation of PEO chains was generated from this parent dendrimer-like PEO of fourth generation using a "conventional" AB(2)-type branching agent, and 48 PEO branches could be grown by AROP. The 48 outer hydroxy-end groups of the fifth-generation dendrimer-like PEO obtained were subsequently quantitatively converted into inert benzylic groups using benzyl bromide. The 21 internal vinylic groups carried by the PEO scaffold were then chemically modified in a two-step sequence into bromoester groups. The latter which are atom transfer radical polymerization (ATRP) initiating sites thus served to grow poly(tert-butylacrylate) chains. After a final step of hydrolysis of the tert-butyl ester groups, double, hydrophilic, dendrimer-like PEOs comprising 21 internal junction-attached poly(acrylic acid) (PAA) blocks could be obtained. Dynamic light scattering was used to determine the size of these dendrimer-like species in water and to investigate their response to pH variation: in particular, how the pH-sensitive complexation of EO and AA units affects their overall behavior.

Acrylic Resins↗
PubMed1988

Analysis of macromolecular ethylene oxide adducts.

Ethylene oxide is a carcinogenic compound which is also an ethylene metabolite. Ethylene oxide forms macromolecular adducts with proteins and nucleic acids. Targets in proteins are the amino acids cysteine, histidine and valine (if N-terminal, as in hemoglobin). The major DNA adduct is 7-(2-hydroxyethyl)-guanine. Methods for detection of this adduct include radiolabelling and GC-MS. The sensitivity of current GC/MS methods can be improved by selective enrichment of adducts from DNA samples. Studies in this direction are presently being performed.

Alkylation↗
PubMed2001

Fractionation of functional polystyrenes, poly(ethylene oxide)s and poly(styrene)-b-poly(ethylene oxide) by liquid chromatography at the exclusion-adsorption transition point.

The paper reports the fractionation of functional polystyrenes (PSs) and poly(ethylene oxide)s (PEOs) as well as their block copolymers, by liquid chromatography at the exclusion adsorption transition point (EATP-LC), also called "critical conditions" mode. In this specific elution mode (EATP-LC), the fractionation is only governed by the nature and the number of functions attached to the polymer backbone, independent of the molar mass distribution of the whole sample. Functional polystyrenes (alpha- and/or alpha,omega-alcohol-, acetal-, aldehyde- and acidic-PS) could be readily separated from non-functional polystyrenes under various chromatographic conditions. The technique also allowed the fractionation of poly(ethylene oxide)s and PS-PEO block copolymers. In the latter cases, moderately polar columns (grafted silica) and water-based polar eluents were required to obtain a satisfactory fractionation.

Adsorption↗