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At least 91 records · Page 5Linked to original sources
PubMed1993

Subzero nonfreezing storage of the mammalian cardiac explant. I. Methanol, ethanol, ethylene glycol, and propylene glycol as colligative cryoprotectants.

We employed hyperosmotic concentrations of penetrating cryoprotective agents (CPA) to store the isolated rat hearts unfrozen at subzero temperatures. The effect of acute exposure to CPA was assessed by flushing the hearts with CP-14, a cardioplegic solution, containing methanol (MeOH), ethanol (EtOH), ethylene glycol (EG), or propylene glycol (PG) for 2 min and reperfusing immediately with Krebs-Henseleit buffer in a working-heart model. The maximal doses that did not cause irreversible suppression of heart function were: MeOH, 1.78 M; EtOH, 1.27 M; EG, 0.84 M; and PG, 0.87 M. For nonfreezing storage, the hearts were flushed with CP-14 containing the highest tolerable concentrations of MeOH, EtOH, EG, or PG, stored for 6 h at -3.7, -2.8, and -1.4 degrees C, respectively, and then reperfused. Control cardiac output (CO) was 76.2 +/- 1.8 ml/min. Post-reperfusional recovery of CO was 86% in MeOH hearts, 82% in EtOH hearts, 76% in EG hearts, and 79% in PG hearts. Thus MeOH offered not only the least cardiac-suppressing effect but the lowest nonfreezing storage temperature. When storage time was extended, recovery and myocardial ATP level decreased with time in hearts flushed with CP-14 + 1.78 M MeOH and stored at -3.7 degrees C. The decay of function was faster than the decay of ATP level, suggesting energy was better preserved than function. The low return of function, however, may be related to CPA toxicity, osmotic stress, and ischemia/reperfusion injury. Nonfreezing storage at subzero temperatures using these CPAs may provide a novel approach to long-term cardiac preservation.

Adenine Nucleotides↗
PubMed1992

The toxicokinetics of 1,3-butylene glycol versus ethanol in the treatment of ethylene glycol poisoning.

Ethylene glycol (EG) is a toxic chemical found in antifreeze and heat exchangers. Standard therapy for EG intoxication in administration of ethanol (ETOH) to inhibit its metabolism by alcohol dehydrogenase (ADH). Studies indicate 1,3-butylene glycol (BG) binds to ADH more efficiently than EG and is orally less toxic than EG or ETOH. Male rats were divided into 5 groups of 6 animals. Groups received by oral intubation a single dose of EG (32 mmole/kg), BG (39 mmole/kg) initially and every 6 h up to 72 h, ETOH (39 mmole/kg) initially and every 6 h up to 72 h, or EG initially and then either BG or ETOH every 6 h up to 72 h. Administration of ETOH produced hepatotoxicity and pulmonary pathology as indicated by changes in clinical chemistry, urinalysis, and histopathology, while BG did not. Neither ETOH nor BG produced any apparent nephrotoxicity. ETOH produced ataxia, lethargy and central nervous system depression while BG did not. BG produced a higher concentration of urinary EG indicating a better inhibition of ADH metabolism of EG. Ethanol produced a higher EG blood concentration than BG. Ethanol's higher EG blood concentration may be partially attributed to dehydration and a decreased urine output as well as inhibition of ADH metabolism. Ethanol produced mortality in all animals prior to 72 h. The EG/ETOH combination produced mortality more quickly due to additive toxicity of the combination. Lack of any significant toxicity produced by BG and the production of significant toxicities by ETOH indicates that BG is potentially a better antidote than ETOH.

Alcohol Dehydrogenase↗
PubMed1996

Simultaneous determination of ethylene glycol and its major toxic metabolite, glycolic acid, in serum by gas chromatography.

We developed a gas-chromatographic procedure for the simultaneous determination of ethylene glycol (EG) and its major toxic metabolite, glycolic acid (GA), suitable for clinical use in instances of EG intoxication. After serum protein precipitation with acetonitrile (containing internal standard), the supernate is treated with 2,2-dimethoxypropane (containing dimethylformamide) to remove water, and the volume is then reduced by evaporation to <100 microL of dimethylformamide (but not to dryness). After trimethylsilyl derivatization, the resulting derivatives are analyzed by capillary column gas chromatography. Only 100 microL of serum is required and the entire determination, including calibrators and controls, takes <2 h. The method gives a linear response to at least 10 g/L EG and 5 g/L GA and has a limit of detection <10 mg/L. Intraassay CV is < or = 2.8% for EG (100 and 1000 mg/L) and GA (100 and 500 mg/L); between-day CV is < or = 6.5%. The absolute recovery from serum was 91% for EG and 77-82% for GA (200 and 2000 mg/L each). Relative to calibrators prepared bovine serum albumin (70 g/L), the recovery was 99-104% for EG (100 - 5000 mg/L) and 95-105% for GA (50 - 2500 mg/L). No clinically important interference was detected for >60 exogenous or endogenous compounds and drugs.

Acetonitriles↗
PubMed1992

Hydroxypropyl cellulose/poly(ethylene glycol)-co-poly(propylene glycol) aqueous two-phase systems: system characterization and partition of cells and proteins.

Novel aqueous polymeric two-phase systems are described. These systems are formed by mixing hydroxypropyl cellulose (molecular mass 100,000, trade name Klucel L) with poly(ethylene glycol)-co-poly(propylene glycol) copolymer [molecular mass 6,500, poly(propylene glycol) content 50% w/w, trade name Pluronic P105], in a saline buffer. The phase diagram was measured and the interfacial tensions, phase separation times, and lower phase viscosities of three phase systems having constant Pluronic P105 concentration but varying in Klucel L concentration were determined. The partition behavior of a representative cell, bacterium, and protein and the affinity ligand-mediated alteration in the partition behavior of a protein from a yeast extract protein mixture were also characterized. The results suggest that Klucel L/Pluronic P105 phase systems may be cost-effective substitutes for, or complements to, existing aqueous polymeric phase systems. The physical characterization and representative partition data reported here should facilitate application of these new systems.

Cell Separation↗
PubMed1978

Effect of glycidate, an inhibitor of glycolate synthesis in leaves, on the activity of some enzymes of the glycolate pathway.

Under conditions where glycolate synthesis was inhibited at least 50% in tobacco (Nicotiana tabacum L.) leaf discs treated with glycidate (2,3-epoxypropionate), the ribulose diphosphate carboxylase activity in extracts and the inhibition of the activity by 100% oxygen were unaffected by the glycidate treatment. [1-(14)C]Glycidate was readily taken into leaf discs and was bound to leaf proteins, but the binding occurred preferentially with proteins of molecular weight lower than ribulose diphosphate carboxylase. Glycidate added to the isolated enzyme did not inhibit ribulose diphosphate carboxylase activity or affect its inhibition by 100% O(2). Thus, glycidate did not inhibit glycolate synthesis by a direct effect on ribulose diphosphate carboxylase/oxygenase.NADH-glyoxylate reductase and phosphoglycolate phosphatase activities were also unaffected in extracts of leaf discs supplied with glycidate, but NADPH-glyoxylate reductase was inhibited about 35% in such extracts. Addition of 10 mm glycidate to isolated NADPH-glyoxylate reductase inhibited the activity about 25% after 15 minutes of reaction.The small inhibition of NADPH-glyoxylate reductase by glycidate may help to explain the increase in glyoxylate concentration found in glycidate-treated leaf discs. Increasing the glyoxylate pool size in leaf discs has been shown to effectively block glycolate synthesis and photorespiration and increase net photosynthesis. Thus, the similar effects brought about by glycidate in leaf discs can be attributed to indirect effects of metabolic regulation.

Journal Article↗
PubMed1994

Poly(ethylene) glycol monomethyl ethers - an alternative to poly(ethylene) glycols in protein crystallization.

Poly(ethylene) glycol monomethyl ethers (Peg-mmes) are a series of methyl substituted poly(ethylene) glycols that have been used with some success in the crystallization of a number of hydrophobic proteins. Crystallization of a lipase from Humicola lanuginosa complexed with the C12 substrate analogue from Peg-mme 5000, an endoglucanase 1 and a 59 kDa fragment of human topoisomerase IIalpha crystallized from Peg-mme are described. The use of Peg-mme for improving the quality of crystals previously grown from normal poly(ethylene) glycol 8000 is also described. We suggest that these modified Peg-mmes should be regularly used in screening for crystallization.

Journal Article↗
PubMed1989

Percutaneous toxicity of ethylene glycol monomethyl ether and of dipropylene glycol monomethyl ether in the rat.

The subacute percutaneous toxicity of dipropylene glycol monomethyl ether (DPM) in male rats dosed 5 days/week for 4 weeks under both occluded and unoccluded conditions has been assessed and compared to the percutaneous toxicity of ethylene glycol monomethyl ether (EGM). DPM caused no significant changes in the clinical chemistry, haematology, or pathology, whereas EGM caused changes in the haematology and clinical chemistry, and both testicular and bone marrow damage at doses of 1000 mg/kg per day.

Administration, Topical↗
PubMed1978

Microbial metabolism of aliphatic glycols. Bacterial metabolism of ethylene glycol.

A species of Flavobacterium isolated from pond water by its ability to grow aerobically on ethylene glycol as the role source of carbon initially oxidised the diol to glyoxylate via glycollate. The glyoxylate was metabolised by the glycerate pathway to acetyl-CoA. The acetyl-CoA was further metabolised by the tricarboxylic acid cycle plus malate synthase acting anaplerotically.

Culture Media↗
PubMed2003

Characterization of polyethylene glycols and polypropylene glycols by capillary zone electrophoresis and micellar electrokinetic chromatography.

Methods based on capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) have been developed and optimized for the separation of polyethylene glycols (PEGs) and polypropylene glycols (PPGs). To provide for charge and detectability both types of polymeric compounds were derivatized with phthalic anhydride (PhAH) or 1,2,4-benzenetricarboxylic anhydride (BTA) before the separation. Derivatization with BTA yielded more complex electropherograms, due to the occurrence of different isomeric reaction products for every PEG or PPG species. Effective mobilities of the PhAH derivatives were related to the number of monomer units in the polymers in a straightforward way. The CZE method could also be used to determine the monomer-number distribution of random and block PEG-PPG copolymers. For an MEKC analysis the PEGs and PPGs were derivatized with phenyl isocyanate. Oligomers of PEGs could be separated up to molecular masses of 5,000, while for the more hydrophobic PPGs oligomeric separation was only accomplished for molecular masses of up to 1,500. Due to a strongly different separation mechanism for the PEG and PPG derivatives in the MEKC system. a complete group separation of the two types of polymer molecules could be obtained.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed1998

Direct transfer of bovine embryos frozen-thawed in the presence of propylene glycol or ethylene glycol under on-farm conditions in an integrated embryo transfer program.

An integrated bovine embryo transfer program was conducted in collaboration with 11 Japanese prefectural livestock experiment stations. The program was conducted to evaluate the practicability of the direct transfer method for bovine embryos frozen-thawed in the presence of propylene glycol (PG) or ethylene glycol (EG) under on-farm conditions. Embryos at the compacted morula to expanded blastocyst stages were collected from superovulated donors on Day 7 or 8 after estrus and equilibrated in 1.6 M PG or 1.8 M EG in Dulbecco's phosphate-buffered saline (DPBS) supplemented with 20% heat-inactivated calf serum. Embryos were then loaded individually into a 0.25-ml straw and placed directly into a cooling chamber of a programmable freezer precooled to -7 degrees C. After 2 min, the straw was seeded, maintained at -7 degrees C for 8 min more, and then cooled to -30 degrees C either at 0.3 degree C/min or 0.5 degree C/min before being plunged into liquid nitrogen. Embryos at the same stages were also frozen in the presence of 1.4 M glycerol (GLY) by a conventional method, which served as a control. The frozen embryos were thawed by allowing the straws to stand in air for 5 to 10 sec and then immersing them in a 30 degrees C water bath. Embryos frozen-thawed in the presence of PG or EG were nonsurgically transferred into the uterine horn without diluting the cryoprotectant. Embryos frozen-thawed in the presence of GLY were nonsurgically transferred after removing GLY either by the stepwise method (GLY-I) or by in situ dilution with 0.3 M sucrose solution (GLY-II). A total of 1,273 (PG: 400, EG: 418, GLY-I: 177, GLY-II; 278) frozen-thawed embryos was transferred into recipients, yielding 545 pregnancies (overall: 42.8%, PG: 36.0%, EG; 44.7%, GLY-I; 48.6%, GLY-II; 46.0%). The pregnancy rate with PG was significantly lower than that with EG or GLY-II (P < 0.05). The pregnancy rate was affected by the type of cryoprotectant, the region where the embryo transfer program was carried out, the developmental stage of the embryos, the parity of the recipients, and corpus luteum (CL) quality of the recipients. There were no differences in rates of abortion and stillbirth among the 3 cryoprotectants. The present study demonstrates that EG can be effectively used as a cryoprotectant for freezing and direct transfer of bovine embryos, and that the direct transfer method is applicable under on-farm conditions.

Animals↗
PubMed2003

Effect of ethylene glycol and polyethylene glycol on the acid-unfolded state of trypsinogen.

Effect of increasing concentrations of two of the polyols, ethylene glycol (EG) and polyethylene glycol (PEG), was studied by near and far circular dichroism (CD), fluorescence emission spectroscopy, and binding of hydrophobic dye, 1-anilino-8-naphthalene sulfonic acid (ANS). Far-UV CD spectra show the transition of acid-unfolded trypsinogen from an unordered state to an intermediate state having ordered secondary structure. Interestingly, near-UV CD spectra show some amounts of stabilizing effect on the tertiary structure of the protein also. Tryptophan fluorescence studies indicate the change in the environment of the tryptophan residues on addition of EG and PEG. Maximum ANS binding occurs in presence of 80% EG and 90% PEG (v/v), suggesting the presence of an intermediate or molten globule-like state at high concentrations of the two polyols.

Anilino Naphthalenesulfonates↗
PubMed1971

The effects of certain glycols, substituted glycols and related organic solvents on the thermal stability of soluble collagen.

The effects of a number of related diols, substituted diols and glycerol on the thermal stability of acid-soluble calf skin collagen were investigated. Thermal transition temperatures were determined by optical rotation measurement. Short-chain diols with terminal hydroxyl groups, i.e. ethylene glycol and propane-1,3-diol, stabilized the protein at all accessible concentrations. Stabilization was also observed with glycerol and diethylene glycol. Higher homologues in the diol series produced various effects, as did hydroxyl-group positional isomerism. Monoalkyl substitution of diols progressively lowered the denaturation temperature of collagen. Results are discussed in relation to possible mechanisms of perturbant action.

Animals↗
PubMed1999

A review of the comparative mammalian toxicity of ethylene glycol and propylene glycol.

The purpose of this article is to review and interpret the scientific literature on the mammalian toxicity of ethylene glycol (EG) and propylene glycol (PG), with the goal of comparing the toxicity of the two chemicals. This type of review may serve as the basis for risk management decision-making. Because EG is not a GRAS (generally recognized as safe) chemical, its uses are restricted when compared with PG; thus, certain routes of exposure are not relevant here for toxicological comparison (e.g., subcutaneous, intramuscular, and intravenous). Therefore, this review is focused on the oral, inhalation, and dermal routes of exposure. However, where toxicological data derived from an alternative route of exposure serve to eludicate mechanisms of toxicity, data from these routes are considered. Based on the review provided herein, the following conclusions can be drawn. From the standpoint of lethality, acute effects, and reproductive, developmental, and kidney toxicity, the toxicity of EG exceeds that of PG. Further, localized dermal effects from EG and PG are both mild, with data suggesting that PG may have a skin contact sensitization potential. Finally, PG exposure in laboratory animals has been associated with reversible hematological changes; no data were located for EG from which to draw a toxicological comparison.

Animals↗
PubMedDate not supplied

Simultaneous determination of ethylene glycol and glycolic acid in serum by gas chromatography-mass spectrometry.

We describe a gas chromatographic-mass spectrometric (GC-MS) procedure for the simultaneous determination of ethylene glycol (EG) and its major toxic metabolite, glycolic acid (GA), in serum. In this method, serum (50 microL) is treated with 150 microL of glacial acetic acid/acetonitrile (1:10, v/v; contains internal standard, 1,3-propanediol, 15 mg/dL) to precipitate protein. After centrifugation, 10 microL of supernate is treated with 500 microL of 2,2-dimethoxypropane/dimethylformamide (80:20, v/v) to convert water to methanol, and the volume is then reduced to < 100 microL of dimethylformamide (but not to dryness). After formation of tertbutyldimethylsilyl derivatives, analysis is performed by capillary column GC-MS in selected ion mode. The method gives a linear response to 1000 mg/L each EG and GA (16.1 mmol/L and 13.2 mmol/L, respectively) and has a lower limit of detection and a lower limit of quantitation of 10 mg/L each EG and GA (0.16 mmol/L and 0.13 mmol/L, respectively). Total assay imprecision is CV < or = 6.4% (200 and 800 mg/L EG and GA [3.2 and 12.9 mmol/L EG; 2.6 and 10.5 mmol/L GA, respectively]). Absolute recovery from human serum was 91.1% for EG and 77.6% for GA. The procedure is free from any known interference. A complete analysis set (three calibrators, patient serum neat, patient serum diluted 1:5 (v/v), and two controls) may be completed in about 2 h. A preliminary result, based on a single calibrator and patient serum diluted 1:5 (v/v), is complete in about 1 h. The method has been used to aid the diagnosis and management in 34 cases of EG intoxication. Selected cases are briefly reviewed.

Ethylene Glycol↗
PubMed2001

Dose-dependent nonlinear pharmacokinetics of ethylene glycol metabolites in pregnant (GD 10) and nonpregnant Sprague-Dawley rats following oral administration of ethylene glycol.

The kinetics of orally administered ethylene glycol (EG) and its major metabolites, glycolic acid (GA) and oxalic acid (OX), in pregnant (P; gestation day 10 at dosing, GD 10) rats were compared across doses, and between pregnant and nonpregnant (NP) rats. Groups of 4 jugular vein-cannulated female rats were administered 10 (P and NP), 150 (P), 500 (P), 1000 (P), or 2500 (P and NP) mg (13)C-labelled EG/kg body weight. Serial blood samples and urine were collected over 24-hr postdosing, and analyzed for EG, GA, and OX using GC/MS techniques. Pharmacokinetic parameters including Cmax, Tmax, AUC, and betat((1/2)) were determined for EG and GA. Pregnancy status (GD 10-11) had no impact on the pharmacokinetic parameters investigated. Blood levels of GA were roughly dose-proportional from 10 to 150 mg EG/kg, but increased disproportionately from 500 to 1000 mg EG/kg. EG and GA exhibited dose-dependent urinary elimination at doses > or = 500 mg EG/kg, probably due to saturation of metabolic conversion of EG to GA, and of GA to downstream metabolites. The shift to nonlinear kinetics encompassed the NOEL (500 mg EG/kg) and LOEL (1000 mg EG/kg) for developmental toxicity of EG in rats, providing additional evidence for the role of GA in EG developmental toxicity. The peak maternal blood concentration of GA associated with the LOEL for developmental toxicity in the rat was quite high (363 microg/g or 4.8 mM blood). OX was a very minor metabolite in both blood and urine at all dose levels, suggesting that OX is not important for EG developmental toxicity.

Administration, Oral↗
PubMed2005

Development of a physiologically based pharmacokinetic model for ethylene glycol and its metabolite, glycolic Acid, in rats and humans.

An extensive database on the toxicity and modes of action of ethylene glycol (EG) has been developed over the past several decades. Although renal toxicity has long been recognized as a potential outcome, in recent years developmental toxicity, an effect observed only in rats and mice, has become the subject of extensive research and regulatory reviews to establish guidelines for human exposures. The developmental toxicity of EG has been attributed to the intermediate metabolite, glycolic acid (GA), which can become a major metabolite when EG is administered to rats and mice at high doses and dose rates. Therefore, a physiologically based pharmacokinetic (PBPK) model was developed to integrate the extensive mode of action and pharmacokinetic data on EG and GA for use in developmental risk assessments. The resulting PBPK model includes inhalation, oral, dermal, intravenous, and subcutaneous routes of administration. Metabolism of EG and GA were described in the liver with elimination via the kidneys. Metabolic rate constants and partition coefficients for EG and GA were estimated from in vitro studies. Other biochemical constants were optimized from appropriate in vivo pharmacokinetic studies. Several controlled rat and human metabolism studies were used to validate the resulting PBPK model. When internal dose surrogates were compared in rats and humans over a broad range of exposures, it was concluded that humans are unlikely to achieve blood levels of GA that have been associated with developmental toxicity in rats following occupational or environmental exposures.

Animals↗
PubMed1984

Toxicities of ethylene glycol and ethylene glycol monoethyl ether in Fischer 344/N rats and B6C3F1 mice.

The toxicities of ethylene glycol (EG) and ethylene glycol monoethyl ether (EGEE) were studied in Fischer 344/N rats and B6C3F1 mice. In a 13-week study, EG was administered in feed to groups of 10 rats and 10 mice of both sexes at dose levels of 0 (control), 0.32, 0.63, 1.25, 2.5 and 5.0%. Kidney/body weight ratios were elevated in the 2.5 and 5.0% dose groups of male and female rats relative to controls, while serum urea nitrogen and serum creatinine levels were elevated in the two highest dose groups of male rats. Toxic nephrosis and crystal deposits in renal tubules were observed in the 2.5 and 5.0% dose groups of male rats. Crystals were also observed in brains of male rats in the 5.0% dose group. Nephrosis was the only lesion observed in female rats (5.0% dose group). Mild, compound-related lesions were seen in kidneys (nephrosis) and livers (centrilobular degeneration) of male mice in the 2.5 and 5.0% dose groups. There were no adverse effects observed in female mice. Groups of 50 rats and 50 mice of both sexes were administered EGEE by gavage in a 2-year study at dose levels of 0 (control), 0.5, 1.0 and 2.0 g/kg body weight. Testicular atrophy was observed in male rats that died early in this study and in the medium- and high-dose male mouse groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Ethylene glycol monomethyl ether (EGME) and propylene glycol monomethyl ether (PGME): inhalation fertility and teratogenicity studies in rats, mice and rabbits.

A combined dominant lethal-fertility study was conducted in which male and female Sprague-Dawley (CD) rats were exposed to 0, 30, 100 or 300 ppm of ethylene glycol monomethyl ether (EGME) vapor for 6 hr/day, 5 days/week for 13 weeks and then mated to untreated counterparts. Among males, fertility was completely suppressed after exposure to 300 ppm. A partial restoration of reproductive function was evident following 13 weeks of recovery. No treatment-related reproductive effects were observed among males exposed subchronically to 100 ppm, or among females exposed to 300 ppm or below of EGME. Studies to assess the effects of inhaled EGME on embryonal and fetal development were also conducted in Fischer 344 rats, CF-1 mice, and New Zealand White rabbits. Rats and rabbits were exposed to concentrations of 0, 3, 10 or 50 ppm for 6 hr/day on days 6-15 or 6-18 of gestation, respectively. Exposure of rabbits to 50 ppm resulted in significant teratologic effects, an increased resorption rate, and decreased fetal body weight. Slight fetotoxicity in the form of skeletal variations were observed among rats exposed to 50 ppm. Exposure of pregnant mice to 0, 10, or 50 ppm for 6 hr/day on days 6-15 of gestation resulted in slight fetotoxicity at 50 ppm. No significant treatment-related effects were observed at 10 ppm of EGME or below in any of the species tested. Separate groups of pregnant rats and rabbits were exposed to 0, 500, 1500 or 3000 ppm of propylene glycol monomethyl ether (PGME) during organogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗