Ethylene Glycol - Polyethylene Glycol (EG-PEG) Mixtures: Infrared Spectra Wavelet Cross-Correlation Analysis

Infrared spectra were collected on mixtures of ethylene glycol (EG) and polyethylene glycol 600 (PEG600) as a function of weight fraction from pure EG to pure PEG600. In this paper, it will be shown that while the OH vibrational contribution drastically reduces its center frequency from 3450 cm^-1 to 3300 cm^-1 in the weight fraction range 0-25%, the displacement of the mixture spectral features of the mixtures from ideal behavior, i.e., in the absence of interaction, shows the presence of a non-ideal mixing process. Furthermore, wavelet cross-correlation analysis of the registered pairs of spectra and of the intramolecular O-H stretching contributions reveals how the addition of a small amount of pure EG to PEG600 dramatically influences the structural properties of the polymeric matrix, owing to an increase the intermolecular connectivity. In particular, the wavelet cross-correlation parameters, evaluated between each pair of the registered data as a function of weight fraction, in a linear-logarithmic plot, reveals an inflection point for a weight fraction of about 25% of EG, which confirms that, within the three-dimensional networks of hydrogen-bonded EG-PEG600 molecules, a key role is played by EG in determining an increase in the hydrogen-bond network density.

Synthesis of Copper Nanoparticles in Ethylene Glycol by Chemical Reduction with Vanadium (+2) Salts

Copper nanoparticles have been synthesized in ethylene glycol (EG) using copper sulphate as a precursor and vanadium sulfate as an atypical reductant being active at room temperature. We have described a technique for a relatively simple preparation of such a reagent, which has been electrolytically produced without using standard procedures requiring an inert atmosphere and a mercury cathode. Several stabilizing agents have been tested and cationic capping agents have been discarded owing to the formation of complex compounds with copper ions leading to insoluble phases contaminating the metallic nanoparticles. The elemental copper nanoparticles, stabilized with polyvinylpyrrolidone (PVP) and sodium dodecyl sulphate (SDS), have been characterized for composition by energy dispersive X-ray spectroscopy (EDS), and for size by dynamic light scattering (DLS), and transmission electron microscopy (TEM), giving a size distribution in the range of 40-50 nm for both stabilizing agents. From a methodological point of view, the process described here may represent an alternative to other wet-chemical techniques for metal nanoparticle synthesis in non-aqueous media based on conventional organic or inorganic reductants.

Evaluation of protective effects of diosmin (a citrus flavonoid) in chemical-induced urolithiasis in experimental rats

Context There have not been any conclusive studies of the effects of diosmin, a modified flavanone glycoside obtained from Teucrium gnaphalodes L'Her (Lamiaceae), on urolithiasis. Objective To evaluate anti-urolithiatic effects of diosmin in ammonium chloride and ethylene glycol-induced renal stone in experimental animals. Materials and methods Thirty Sprague-Dawley were divided into five groups (n=6) receiving the following treatments, respectively, p.o. for 15 consecutive days: distilled water, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + cystone® 750 mg/kg, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + diosmin 10 mg/kg or 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + diosmin 20 mg/kg. Different biomarkers of urolithiasis in urine and serum were evaluated and histopathological examination of kidney was done. Results Animals treated with diosmin (both 10 and 20 mg/kg) had significantly (p < 0.005) decreased in kidney weight, urinary pH, total urinary protein, urinary calcium, phosphorus, serum potassium, sodium, magnesium, creatinine, uric acid and blood urea nitrogen levels and significantly (p < 0.005) increased in urinary volume, urinary magnesium, potassium, sodium, creatinine, uric acid and serum calcium levels in comparison to animals treated with ethylene glycol and ammonium chloride. However, results were better with diosmin 20 mg/kg in comparison to the control group. Conclusion Diosmin (10 and 20 mg/kg) has very good anti-urolithiatic activity similar to the standard drug cystone®.

Tailoring Graphene Nanosheets for Highly Improved Dispersion Stability and Quantitative Assessment in Nonaqueous Solvent

Aggregation is a critical limitation for the practical application of graphene-based materials. Herein, we report that graphene oxide (GO) nanosheets chemically modified with ethanolamine (EA), ethylene glycol (EG), and sulfanilic acid (SA) demonstrate superior dispersion stability in organic solvents, specifically EG, based on the differences in their covalent chemistries. Functionalized GO was successfully dispersed in EG at a concentration of 9.0 mg mL(-1) (0.50 vol %), the highest dispersion concentration reported to date. Moreover, our study introduces a unique analytical method for the assessment of dispersion stability and successfully quantifies the instability index based on transmission profiles under centrifugation cycles. Interestingly, GO-EG and GO-EA exhibited highly improved dispersion stabilities approximately 96 and 48 times greater than that of GO in EG solvent, respectively. This finding highlights the critical role of surface functional groups in the enhancement of chemical affinity and miscibility in the surrounding media. We anticipate that the novel structural designs and unique tools presented in this study will further the understanding and application of chemically functionalized carbon materials.

Smoke on the water: A case report of chronic renal failure resulting from the ingestion of smoke machine fluid

We report the case of an 18-year-old male admitted to the Intensive Care Unit in Basingstoke and North Hampshire Hospital, who developed chronic kidney disease following the ingestion of smoke machine fluid. Smoke machine fluid may contain ethylene glycol, and a diagnosis of ethylene glycol toxicity with calcium oxalate nephropathy was made. This case resulted in a National Poisons Information Service internal review of the subject and a new TOXBASE entry for smoke machine fluid ingestion.

Antidotes for poisoning by alcohols that form toxic metabolites

The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience.

Bryophyllum pinnatum Leaf Extracts Prevent Formation of Renal Calculi in Lithiatic Rats

BACKGROUND

Bryophyllum pinnatum, commonly known as Pattharcaṭṭa, is used traditionally in ethnomedicinal practices for the treatment of kidney stone and urinary insufficiency.

AIM

The present study evaluated the effect of Bryophyllum pinnatum on ethylene glycol (EG)-induced renal calculi in rats.

MATERIALS AND METHODS

Renal calculi were induced in rats by administration of 0.75% EG in drinking water and co-treated orally with standard drug, Cystone (750 mg/kg), or alcoholic and hydro-alcoholic extracts in doses of 100, 200 and 400 mg/kg for 28 days. Weekly body weights were recorded. On day 29, urolithiasis was confirmed by assessing the urinary parameters (urine volume, pH, uric acid, calcium, phosphorus, oxalate, magnesium and creatinine clearance), serum biochemical parameters (creatinine, uric acid, urea, calcium, phosphorus and magnesium), oxidative stress parameters and histology of kidney.

RESULTS

Treatment with extracts attenuated the EG-induced decrease in body weight and elevation in urinary parameters (uric acid, calcium, phosphorus and oxalate) and serum biochemical parameters (creatinine, uric acid, urea, calcium, phosphorus and magnesium). Extract treatment also reversed EG-induced decrease in urine volume, pH, magnesium and creatinine clearance, oxidative and histological damages in kidneys. Results were comparable to standard drug, Cystone. Results indicated that EG administration caused renal calculi formation which is prevented by treatment with extracts. The observed antilithiatic effect may be attributed to the presence of high content of phenolics, flavonoids and saponins in the extracts.

CONCLUSION

Bryophyllum pinnatum leaves showed preventive effect against renal calculi formation and validates its ethnomedicinal use in urinary disorders. It further supports its therapeutic potential for the treatment of urinary calculi.

Engineering a novel biosynthetic pathway in Escherichia coli for production of renewable ethylene glycol

Ethylene glycol (EG) is an important commodity chemical with broad industrial applications. It is presently produced from petroleum or natural gas feedstocks in processes requiring consumption of significant quantities of non-renewable resources. Here, we report a novel pathway for biosynthesis of EG from the renewable sugar glucose in metabolically engineered Escherichia coli. Serine-to-EG conversion was first achieved through a pathway comprising serine decarboxylase, ethanolamine oxidase, and glycolaldehyde reductase. Serine provision in E. coli was then enhanced by overexpression of the serine-biosynthesis pathway. The integration of these two parts into the complete EG-biosynthesis pathway in E. coli allowed for production of 4.1 g/L EG at a cumulative yield of 0.14 g-EG/g-glucose, establishing a foundation for a promising biotechnology.

Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR)

Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR), has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1-x)NixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape) and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO4)2 nanoparticles (NPs) can be obtained with a production rate of about 1-10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

Ultrathin Surface Chemistry to Delay Anion Fouling

The unwanted fouling of surfaces by ionic adsorption has received little research attention. In this context, ultrathin organic adlayer surface chemistry-featuring monoethylene glycol based molecular residues-is described that is capable of noticeably decreasing the rate of anion depletion from solution. The strategy is exemplified with glass as the substrate material and fluoride as the anion foulant.

Toxicology and the biological role of methanol and ethanol: Current view

BACKGROUND

Alcohol variants such as ethanol and methanol are simple organic compounds widely used in foods, pharmaceuticals, chemical synthesis, etc. Both are becoming an emerging health problem; abuse of ethanol containing beverages can lead to disparate health problems and methanol is highly toxic and unfit for consumption.

METHODS AND RESULTS

This review summarizes the basic knowledge about ethanol and methanol toxicity, the effect mechanism on the body, the current care of poisoned individuals and the implication of alcohols in the development of diseases. Alcohol related dementia, stroke, metabolic syndrome and hepatitis are discussed as well. Besides ethanol, methanol toxicity and its biodegradation pathways are addressed.

CONCLUSIONS

The impact of ethanol and methanol on the body is shown as case reports, along with a discussion on the possible implication of alcohol in Alzheimer's disease and antidotal therapy for methanol poisoning. The role of ethanol in cancer and degenerative disorders seems to be underestimated given the current knowledge. Treatment in case of poisoning is another issue that remains unresolved even though effective protocols and drugs exist.

Protective effects of the aqueous extract of Crocus sativus against ethylene glycol induced nephrolithiasis in rats

This study evaluated the possible protective effect of Crocus sativus L. (saffron) in the treatment of renal calculi. Aqueous extract of saffron (25, 50 and 100 mg/kg, daily) was administered intraperitoneally in two regimens of protective or curative, using male Wistar rats. Urolithiasis was induced by ethylene glycol (% 0.75) in drinking water. Urine was collected for biochemical analysis and the kidneys were prepared for total lipid peroxide and histological evaluation. Ethylene glycol feeding resulted in an increased urine output, renal excretion of oxalate and decreased excretion of citrate and magnesium. Saffron did not show diuretic effect; however, it significantly reduced the elevated urinary oxalate in prophylactic (50 and 100 mg/kg) and curative (100 mg/kg) studies. Only the high dose of prophylactic regimen restored citrate concentration of urine. Increased number of calcium oxalate crystals deposits in the kidney tissue of calculogenic rats was significantly reverted by the prophylactic and high dose of curative saffron treatment. Malondialdehyde (MDA, a lipid peroxidation product) in the kidneys was increased following the lithogenic treatment; however, prophylactic (50, 100 mg/kg) and curative (100 mg/kg) regimens with saffron reduced the elevated levels of MDA. Results in the current study indicate that saffron can protect against ethylene glycol induced calcium oxalate (CaOx) nephrolithiasis. The mechanisms underlying this effect are mediated possibly through effect on the urinary concentration of stone-forming constituents and an antioxidant effect.

on Ethylene Glycol-Induced Nephrolithiasis in Laboratory Rats

BACKGROUND

Nephrolithiasis is of the most prevalent urinary tract disease. It seems worthwhile to replace the conventional treatments with more beneficial and safer agents, particularly herbal medicines which are receiving an increasing interest nowadays.

AIMS

In this study, we investigated the protective and curative effects of Achillea millefolium L. on ethylene glycol (EG)-induced nephrolithiasis in rats.

MATERIALS AND METHODS

The extract of A. millefolium was prepared by soxhlet method. Forty male Wistar rats were randomly divided into five groups (N = 8) as follows. The negative control (group A) received tap drinking water. Rats in sham (positive control group B), curative (group C and D), and preventive (group E) groups all received 1% EG in drinking water according to the experimental protocol for 30 days. In the curative groups, dosages of 200 and 400 mg/kg body weight (BW) of A. millefolium extract were administered orally from day 15 to the end of the experiment, group C and D, respectively. Group E received 200 mg/kg A. millefolium extract from the 1(st) day throughout the experiment. Urinary oxalate and citrate concentrations were measured by spectrophotometer on the first and 30(th) days. On day 31, the kidneys were removed and examined histopathologically for counting the calcium oxalate (CaOx) deposits in 50 microscopic fields.

RESULTS

In the curative and preventive groups, administration of A. millefolium extract showed significant reduction in urinary oxalate concentration (P < 0.05). Also, urinary citrate concentration was significantly increased in group C, D, and E. The CaOx deposits significantly decreased in group C to E compared with the group B.

CONCLUSIONS

According to our results, A. millefolium extract had preventive and curative effects on EG-induced renal calculi.

Antinephrolithiatic and antioxidative efficacy of Dolichos biflorus seeds in a lithiasic rat model

CONTEXT

Dolichos biflorus sensu auct non L. (Fabaceae) is widely used for the treatment of kidney stones, leucorrhoea, urinary disorders, and menstrual troubles, and is known for its antioxidant activity.

OBJECTIVES

To evaluate the preventive effect of hydro-alcoholic extract of Dolichos biflorus seeds (DBE) in ethylene glycol induced nephrolithiasis.

MATERIALS AND METHODS

In vitro antioxidative capacity of DBE was estimated in terms of reducing power, superoxide radical, 2,2- diphenyl-1-picrylhydrazyl radical, and nitric oxide scavenging activity. A validated HPLC method was used for standardization using quercetin as a marker. Adult female Wistar rats were administered with DBE (150 and 300 mg/kg body weight/day) along with ethylene glycol (0.75%, v/v) for 28 d. The various biochemical parameters were measured in urine, serum, and kidney followed by histochemistry.

RESULTS

Ethylene glycol caused a significant increase in calcium, oxalate, phosphate, and total protein in urine as well as in kidney whereas decrease in calcium, sodium, and magnesium in serum was observed (p < 0.001). Ethylene glycol also caused a significant increase in lipid peroxidation and concurrent decrease in activities of antioxidant enzymes in kidney (p < 0.001). However, the seed extract of D. biflorus caused significant restoration of all these parameters (p < 0.001). Histopathological and histochemical studies also showed the reduced calcifications in kidney of seed extract treated rats.

DISCUSSION AND CONCLUSION

These results indicated that seeds of D. biflorus have significant prophylactic effect in preventing the nephrolithiasis, which might be due to the antioxidant activity of the active compounds of the plant.

Diethylene glycol poisoning from transcutaneous absorption

A case of transcutaneous diethylene glycol poisoning with severe acute kidney injury, but a positive outcome, is described. A man without significant medical history was admitted to our hospital due to anuria, gastrointestinal symptoms, and hypertension. Ultrasonography excluded vascular damage and postrenal obstruction. Laboratory tests showed acute kidney injury and metabolic acidosis with increased anion gap; hemodialysis therapy was started. The brother of the patient reported that the patient had been smearing his skin with brake fluid containing diethylene glycol to treat a "dermatitis." Only supportive therapy was given due to the lack of a specific antidote. Continuous venovenous hemofiltration was performed. The kidney biopsy showed acute toxic proximal tubulonecrosis, without deposition of oxalate crystals. His neurologic condition worsened dramatically; supportive care was continued. Over time, acute kidney injury and neurologic damage gradually improved; 33 days after admission, he went to a rehabilitation unit for 5 months, with complete clinical recovery. Historically, diethylene glycol has been the cause of large-scale poisonings from ingestion of contaminated drugs. The clinical evolution is unpredictable. Treatment is not well defined; early hemodialysis treatment reduces levels of toxic metabolites, and fomepizole could be useful in cases with an early diagnosis. A comparison of the characteristics of diethylene glycol versus ethylene glycol poisoning is given.

Rapid double-dye-layer coating for dye-sensitized solar cells using a new method

Intensive research with the specific aim of developing inexpensive renewable energy sources is currently being undertaken. In dye-sensitized solar cell (DSSC) production, the most time-consuming process is coating the dye on working electrodes: absorption of ruthenium-based dyes [e.g., N719=bis(trtrabutylammonium)-cis-di(thiocyanato)-N,N'-bis(4-carboxylato-4'-carboxylic acid-2,2'-bipyridine) ruthenium(II)] on a photoanode takes a long time. We report a simple dye-coating method using a mixed solvent of ethylene glycol (EG) and glycerol (Gly). According to our experiments, dye-coating time can be reduced to 5 min from several hours. Maximum performance was obtained with an EG/Gly ratio of 1:1. This mixture of solvents gave a performance of 9.1%. Furthermore, the viscous solvent system could control coating depth; positioning dye coatings to a specific depth was rapid and facile. A cell containing two different dyes (N719+black dye) had an efficiency of 9.4%.

Antioxidative mechanism involved in the preventive efficacy of Bergenia ciliata rhizomes against experimental nephrolithiasis in rats

CONTEXT

Bergenia ciliata Haw. (Saxifragaceae) is widely used in traditional medicines for renal disorders including kidney stones, inflammation and also well known for its antioxidant activity. Use of traditional herbs proved to be an important strategy for the management of kidney stones by modulating the oxidative stress imposed by calcium oxalate nephrolithiasis.

OBJECTIVES

To evaluate the antinephrolithiatic and antioxidative activity of B. ciliata rhizomes as a preventive agent on ethylene glycol (EG)-induced nephrolithiasis.

MATERIALS AND METHODS

The hydro-methanol extract (30:70, v/v) of B. ciliata rhizomes was orally administrated simultaneously at a dose of 150 and 300 mg/kg body weight/day, to adult female Wistar rats for 28 d along with EG (0.75%, v/v) in drinking water. The results were compared to a parallel study conducted with marketed polyherbal drug cystone under identical dosage conditions. The biochemical parameters were measured in urine, serum and kidney followed by histochemistry. A validated HPLC method was used for standardization using gallic acid as a marker.

RESULTS

EG caused a significant increase in calcium, oxalate and phosphate levels in urine and kidney and concurrent decrease in calcium, sodium and magnesium in serum (p<0.001). EG also caused an increase in lipid peroxidation and a decrease in activities of antioxidative enzymes in kidney. Co-treatment with B. ciliata rhizomes extract caused restoration of all these parameters (p<0.001). Histochemical studies showed reduced calcifications with extract treatment.

CONCLUSION

B. ciliata has a significant prophylactic effect in preventing the nephrolithiasis, which might be mediated through antioxidant activity of these active compounds.

The Synthesis of α-MoO₃ by Ethylene Glycol

This study investigated the use of ethylene glycol to form α-MoO₃ (molybdenum trioxide) from ammonium molybdate tetrahydrate at various sintering temperatures for 1 h. During the sintering process, the morphologies of the constituents were observed using scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy was used to explain the reaction process. In this work, the results obtained using X-ray photoelectron spectroscopy (XRD) demonstrated that, when the molybdenum trioxide powder was treated thermally at 300 °C, the material exhibited crystallinity. The peaks were indexed to correspond with the (110), (040), (021), (111), and (060) crystallographic planes, and the lattice parameters of a, b, and c were about 3.961, 13.876, and 3.969 Å. Using these observations, we confirmed that orthorhombic α-MoO₃ was formed for sintering temperatures from 300 to 700 °C. Pattern images were obtained by the selected area electron diffraction pattern (SAED) technique, and the d distance of the high resolution transmission electron microscopy (HRTEM) images were almost 0.39 and 0.36 nm, and the Mo 3d_5/2, Mo 3d_3/2, and O 1s of X-ray photoelectron spectroscopy (XPS) were located at 233.76, 237.03, and 532.19 eV, which also demonstrated that α-MoO₃ powder had been synthesized.

Polarizable empirical force field for acyclic polyalcohols based on the classical Drude oscillator

A polarizable empirical force field for acyclic polyalcohols based on the classical Drude oscillator is presented. The model is optimized with an emphasis on the transferability of the developed parameters among molecules of different sizes in this series and on the condensed-phase properties validated against experimental data. The importance of the explicit treatment of electronic polarizability in empirical force fields is demonstrated in the cases of this series of molecules with vicinal hydroxyl groups that can form cooperative intra- and intermolecular hydrogen bonds. Compared to the CHARMM additive force field, improved treatment of the electrostatic interactions avoids overestimation of the gas-phase dipole moments resulting in significant improvement in the treatment of the conformational energies and leads to the correct balance of intra- and intermolecular hydrogen bonding of glycerol as evidenced by calculated heat of vaporization being in excellent agreement with experiment. Computed condensed phase data, including crystal lattice parameters and volumes and densities of aqueous solutions are in better agreement with experimental data as compared to the corresponding additive model. Such improvements are anticipated to significantly improve the treatment of polymers in general, including biological macromolecules.

Utilization management in toxicology

Recent upward trends in the prevalence of abuse of prescription drugs and illicit substances have resulted in increased demands for toxicology testing to support the emergency department and drug treatment in pain management programs. This review will discuss the challenges faced by clinical laboratories to manage the utilization of toxicology tests, particularly those ordered in managing poisoned patients in the emergency department and chronic pain patients on opioid therapy. Optimal utilization of toxicology tests to support the emergency department relies on selecting the appropriate tests for the patient, and the availability of the results in a timely fashion. Two tiers of toxicology testing systems with different requirements for turnaround time will be discussed. In patients with chronic pain urine drug testing, including screening and confirmation testing are used extensively in pain management to monitor patient compliance. A thorough understanding of the performance characteristics of the test methodologies and drug metabolism is a key to making a proper analytical and clinical interpretation of the test results and will contribute to effective utilization of these tests. In addition, the reimbursement system is an important factor in the decision making process for test selection utilization as significant costs can be incurred by both payers and patients. Collaboration, trust, and effective communication among clinicians, patients, and clinical laboratory professionals are essential for effective utilization of toxicology testing.

Study of antiurolithiatic activity of Asparagus racemosus on albino rats

Aims:

The aim of this study was to investigate the effect of ethanolic extract of Asparagus racemosus on urolithiasis in rats.

Materials and Methods:

Thirty-six male Wistar albino rats were randomly divided into six groups (n = 6). Ethylene glycol (EG) 0.75% and ammonium chloride (AC) 2% in drinking water were fed to all groups (Groups II–VI) except normal control (Group I) rats for 10 days to induce urolithiasis. Group III–VI rats were treated with ethanolic extract of Asparagus racemosus at doses 200, 400, 800, and 1600 mg/kg, respectively, for 10 days. Positive control (Group II) rats were treated with EG/AC alone. Group I rats were administered drinking water and distilled water (6 μl/g) by gavage. After 10 days, blood samples were collected and analyzed for serum concentrations of calcium, phosphorus, urea, and creatinine. The kidneys were removed and sectioned for histopathological examination. The data were presented as mean ± standard error of mean and analyzed using one-way analysis of variance and Student's “t”-test. P < 0.05 was considered statistically significant. Conventional windows software was used for statistical analysis.

Results:

The rats treated with ethanolic extract of A. racemosus at doses 800 and 1600 mg/ kg significantly (P < 0.05) reduced the serum concentrations of calcium, phosphorus, urea, and creatinine. Histopathology of the kidneys in Groups V and VI revealed less tissue damage and were almost similar to Group I rats.

Conclusions:

The ethanolic extract of A. racemosus has protective effect against urolithiasis.

Novel monosaccharide fermentation products in Caldicellulosiruptor saccharolyticus identified using NMR spectroscopy

BACKGROUND

Caldicellulosiruptor saccharolyticus is a thermophilic, Gram-positive, non-spore forming, strictly anaerobic bacterium of interest in potential industrial applications, including the production of biofuels such as hydrogen or ethanol from lignocellulosic biomass through fermentation. High-resolution, solution-state nuclear magnetic resonance (NMR) spectroscopy is a useful method for the identification and quantification of metabolites that result from growth on different substrates. NMR allows facile resolution of isomeric (identical mass) constituents and does not destroy the sample.

RESULTS

Profiles of metabolites produced by the thermophilic cellulose-degrading bacterium Caldicellulosiruptor saccharolyticus DSM 8903 strain following growth on different monosaccharides (D-glucose, D-mannose, L-arabinose, D-arabinose, D-xylose, L-fucose, and D-fucose) as carbon sources revealed several unexpected fermentation products, suggesting novel metabolic capacities and unexplored metabolic pathways in this organism. Both 1H and 13C nuclear magnetic resonance (NMR) spectroscopy were used to determine intracellular and extracellular metabolite profiles. One dimensional 1H NMR spectral analysis was performed by curve fitting against spectral libraries provided in the Chenomx software; 2-D homonuclear and heteronuclear NMR experiments were conducted to further reduce uncertainties due to unassigned, overlapping, or poorly-resolved peaks. In addition to expected metabolites such as acetate, lactate, glycerol, and ethanol, several novel fermentation products were identified: ethylene glycol (from growth on D-arabinose), acetoin and 2,3-butanediol (from growth on D-glucose, L-arabinose, and D-xylose), and hydroxyacetone (from growth on D-mannose, L-arabinose, and D-xylose). Production of ethylene glycol from D-arabinose was particularly notable, with around 10% of the substrate carbon converted into this uncommon fermentation product.

CONCLUSIONS

The present research shows that C. saccharolyticus, already of substantial interest due to its capability for biological ethanol and hydrogen production, has further metabolic potential for production of higher molecular weight compounds, such as acetoin and 2,3-butanediol, as well as hydroxyacetone and the uncommon fermentation product ethylene glycol. In addition, application of nuclear magnetic resonance (NMR) spectroscopy facilitates identification of novel metabolites, which is instrumental for production of desirable bioproducts from biomass through microbial fermentation.

Study on effects of molecular crowding on G-quadruplex-ligand binding and ligand-mediated telomerase inhibition

The telomere G-quadruplex-binding and telomerase-inhibiting capacity of two cationic (TMPyP4 and PIPER) and two anionic (phthalocyanine and Hemin) G-quadruplex-ligands were examined under conditions of molecular crowding (MC). Osmotic experiments showed that binding of the anionic ligands, which bind to G-quadruplex DNA via π-π stacking interactions, caused some water molecules to be released from the G-quadruplex/ligand complex; in contrast, a substantial number of water molecules were taken up upon electrostatic binding of the cationic ligands to G-quadruplex DNA. These behaviors of water molecules maintained or reduced the binding affinity of the anionic and the cationic ligands, respectively, under MC conditions. Consequently, the anionic ligands (phthalocyanine and Hemin) robustly inhibited telomerase activity even with MC; in contrast, the inhibition of telomerase caused by cationic TMPyP4 was drastically reduced by MC. These results allow us to conclude that the binding of G-quadruplex-ligands to G-quadruplex via non-electrostatic interactions is preferable for telomerase inhibition under physiological conditions.

Facile synthesis of ultrathin magnetic iron oxide nanoplates by Schikorr reaction

In this work, a very facile one-pot hydrothermal synthesis approach has been developed for the preparation of ultrathin magnetite nanoplates. The hydrothermal procedure was performed by aging ferrous hydroxide under anaerobic conditions, which is known as Schikorr reaction. Ethylene glycol (EG), which was introduced to the reaction as another solvent, played a critical role in the formation process of these nanoplates. Typically, hexagonal Fe3O4 nanoplates with a thickness of 10 to 15 nm and a side length of 150 to 200 nm have been synthesized with EG/H2O = 1:1 in experiments. Our data suggest that the thickness of Fe3O4 nanoplates decreases, and the shape of the nanoplate becomes more irregular when the concentration of EG increases. The as-prepared Fe3O4 nanoplates were highly crystallized single crystals and exhibited large coercivity and specific absorption rate coefficient.

Effect of common cryoprotectants on critical warming rates and ice formation in aqueous solutions

Ice formation on warming is of comparable or greater importance to ice formation on cooling in determining survival of cryopreserved samples. Critical warming rates required for ice-free warming of vitrified aqueous solutions of glycerol, dimethyl sulfoxide, ethylene glycol, polyethylene glycol 200 and sucrose have been measured for warming rates of order 10-10⁴ K/s. Critical warming rates are typically one to three orders of magnitude larger than critical cooling rates. Warming rates vary strongly with cooling rates, perhaps due to the presence of small ice fractions in nominally vitrified samples. Critical warming and cooling rate data spanning orders of magnitude in rates provide rigorous tests of ice nucleation and growth models and their assumed input parameters. Current models with current best estimates for input parameters provide a reasonable account of critical warming rates for glycerol solutions at high concentrations/low rates, but overestimate both critical warming and cooling rates by orders of magnitude at lower concentrations and larger rates. In vitrification protocols, minimizing concentrations of potentially damaging cryoprotectants while minimizing ice formation will require ultrafast warming rates, as well as fast cooling rates to minimize the required warming rates.

Antiurolithiatic and antioxidant activity of Hordeum vulgare seeds on ethylene glycol-induced urolithiasis in rats

OBJECTIVE

The objective was to investigate the antiurolithiatic and antioxidant activity of ethanolic extract of Hordeum vulgare seeds (EHV) on ethylene glycol-induced urolithiasis in Wistar albino rats.

MATERIALS AND METHODS

Urolithiasis was produced in Wistar albino rats by adding 0.75% v/v ethylene glycol (EG) to drinking water for 28 days. The ethanolic extract of Hordeum vulgare seeds (EHV) was assessed for its curative and preventive action in urolithiasis. In preventive treatment, the EHV given from 1st day to 28th day, while in the curative regimen, the EHV was given from 15th day to 28th day. Various renal functional and injury markers such as urine volume, calcium, phosphate, uric acid, magnesium, urea, and oxalate were evaluated using urine, serum, and kidney homogenate. Antioxidant parameters such as lipid peroxidation, superoxide dismutase, and catalase were also determined.

RESULTS

The EHV treatment (both preventive and curative) increased the urine output significantly compared to the control. The EHV treatment significantly reduced the urinary excretion of the calcium, phosphate, uric acid, magnesium, urea, and oxalate and increased the excretion of citrate compared to EG control. The increased deposition of stone forming constituents in the kidneys of calculogenic rats were significantly lowered by curative and preventive treatment with EHV. It was also observed that the treatment with EHV produced significant decrease in lipid peroxidation, and increased levels of superoxide dismutase and catalase.

CONCLUSION

These results suggest the usefulness of ethanolic extract of Hordeum vulgare seeds as an antiurolithiatic and antioxidant agent.

Antiurolithiatic Effects of Solanum xanthocarpum Fruit Extract on Ethylene-Glycol-Induced Nephrolithiasis in Rats

This study was designed to evaluate the effects of Solanum xanthocarpum fruit extract in ethylene-glycol-induced urolithiasis in the male Wistar rats. Nephrolithiasis was induced in male Wistar rats by adding ethylene glycol (0.75%) in drinking water for 28 days. Animals were divided into six groups, each containing six viz. Vehicle control, model control, S. xanthocarpum methanol extract in different doses of 100, 200, and 400 mg/kg p.o., Cystone (750 mg/kg, p.o.) served as a standard. Hyperoxaluria as well as an increase in the excretion of calcium, phosphate, uric acid and decrease in citrate and magnesium in urine, impairment of renal function and oxidative imbalance in kidney were observed in the calculi-induced group. Treatment with S. xanthocarpum decreases hyperoxaluria, calcium, and uric acid, improves renal function, and also produces antioxidant effects. Crystalluria was characterized by excretion calcium oxalate (CaOX) crystals, which were enormous in the lithogenic group but smaller in the drug-treated group. The histology showed that the calculi-induced group had a large deposition of CaOX crystals in kidney while the treated group had trivial and fewer deposits. The result indicates the antiurolithiatic activity of S. xanthocarpum mediated possibly by CaOX crystal inhibition, diuretic, antioxidant and maintaining balance between stone promoter and inhibitor constituents, and this study rationalized its medicinal use in urolithiasis.

The preventive effect of N-butanol fraction of Nigella sativa on ethylene glycol-induced kidney calculi in rats

Background:

The current study was carried out to determine whether the aqueous-ethanolic extract or the butanolic fraction of Nigella sativa (NS) seeds could prevent or reduce calculi aggregation in experimental calcium oxalate nephrolithiasis in Wistar rats.

Materials and Methods:

Male Wistar rats were randomly divided into 5 groups: group A received tap drinking water for 28 days. Groups B, C, D and E received 1% ethylene glycol for induction of calcium oxalate (CaOx) calculus formation for 28 days. Rats in groups C, D and E also received aqueous-ethanolic extract of NS, N-butanol fraction and N-butanol phase remnant of NS, respectively, in drinking water at a dose of 250 mg/kg for 28 days. Urine concentration of oxalate, citrate, and calcium on days 0, 14, and 28, and also serum concentration of magnesium and calcium on days 0 and 28, were measured. On day 29, kidneys were removed for histopathologic study and examined for counting the calcium oxalate deposits in 10 microscopic fields.

Result:

Treatment of rats with N-butanol fraction and N-butanol phase remnant of NS significantly reduced the number and size of kidney calcium oxalate deposits compared with ethylene glycol group. Urinary concentration of oxalate in all experimental groups increased compared with control group on days 14 and 28, whereas the urine citrate concentration was lower in all experimental groups compared with control group on days 14 and 28.

Conclusion:

N-butanol fraction and N-butanol phase remnant of NS showed a beneficial effect on calcium oxalate deposition in the rat kidney. Therefore, the butanolic fraction of NS may be suggested for prevention of calcium oxalate calculi in humans.

Vitrification of immature bovine cumulus-oocyte complexes: effects of cryoprotectants, the vitrification procedure and warming time on cleavage and embryo development

BACKGROUND

The present studies evaluated the effects of cryoprotectants, the vitrification procedure and time in the warming solution containing sucrose on cleavage and embryo development of immature (GV stage) bovine cumulus-oocyte complexes (COCs).

METHODS

Two experiments were conducted. In Experiment 1, COCs (n = 420) were randomly assigned to four groups: 1) CONTROL GROUP: no treatment; 2) VS1 group: COCs were exposed to vitrification solution 1 (VS1) containing 7.5% ethylene glycol [EG] + 7.5% dimethyl sulfoxide [DMSO] + 20% calf serum [CS] in TCM-199 at 37 C for 5 min; 3) VS1 + VS2 group: COCs were exposed to VS1 for 5 min followed by VS2 (15% EG + 15% DMSO + 17.1% sucrose + 20% CS) at 37 C for 45-60 sec; and 4) Vitrified group: COCs were exposed to VS1 and VS2, loaded on cryotops, vitrified in liquid nitrogen and then warmed in TCM-199 + 17.1% sucrose + 20% CS at 37 C for 1 min. In Experiment 2, COCs (n = 581) were assigned to the same groups, but those in VS1, VS1 + VS2 and Vitrified groups were sub-divided and exposed to the warming solution for either 1 or 5 min. After treatment and/or warming, all COCs in both experiments underwent in vitro maturation, in vitro fertilization and in vitro culture.

RESULTS

Cleavage and blastocyst rates did not differ among Control, VS1 and VS1 + VS2 groups in either experiment. In Experiment 2, there was no effect of time in the warming solution.However, both cleavage and blastocyst rates were lower (P < 0.001) in the Vitrified group than in the Control, VS1 and VS1 + VS2 groups (40.9 and 1.6% vs 92.2 and 34.4%, 79.4 and 25.2%, and 80.2 and 20.8%, respectively in Experiment 1, and 25.0 and 1.7% vs 75.3 and 27.2%, 67.9 and 19.5%, and 62.7 and 22.5%, respectively in Experiment 2).

CONCLUSIONS

The permeating cryoprotectants (EG and DMSO) present in VS1 and VS2 solutions and the time in the warming solution containing sucrose had no adverse effects on cleavage and blastocyst rates of immature bovine COCs. However, cleavage rate and early embryo development were reduced following the vitrification and warming.

Alcea rosea root extract as a preventive and curative agent in ethylene glycol-induced urolithiasis in rats

Introduction:

Alcea rosea L. is used in Asian folk medicine as a remedy for a wide range of ailments. The aim of the present study was to investigate the effect of hydroalcoholic extract of Alcea rosea roots on ethylene glycol-induced kidney calculi in rats.

Materials and Methods:

Male Wistar rats were randomly divided into control, ethylene glycol (EG), curative and preventive groups. Control group received tap drinking water for 28 days. Ethylene glycol (EG), curative and preventive groups received 1% ethylene glycol for induction of calcium oxalate (CaOx) calculus formation; preventive and curative subjects also received the hydroalcoholic extract of Alcea rosea roots in drinking water at dose of 170 mg/kg, since day 0 or day 14, respectively. Urinary oxalate concentration was measured by spectrophotometer on days 0, 14 and 28. On day 28, the kidneys were removed and examined histopathologically under light microscopy for counting the calcium oxalate deposits in 50 microscopic fields.

Results:

In both preventive and curative protocols, treatment of rats with hydroalcoholic extract of Alcea rosea roots significantly reduced the number of kidney calcium oxalate deposits compared to ethylene glycol group. Administration of Alcea rosea extract also reduced the elevated urinary oxalate due to ethylene glycol.

Conclusion:

Alcea rosea showed a beneficial effect in preventing and eliminating calcium oxalate deposition in the rat kidney. This effect is possibly due to diuretic and anti-inflammatory effects or presence of mucilaginous polysaccharides in the plant. It may also be related to lowering of urinary concentration of stone-forming constituents.

Effect of Unex on ethylene glycol-induced urolithiasis in rats

This study was aimed to evaluate the effectiveness of the Unex capsule on albino rats as a preventive agent against the development of kidney stones. The Unex capsule is a marketed product of Unijules Life Sciences, Nagpur, containing the extracts of Boerhaavia diffusa and Tribulus terrestris. Activity of Unex was studied using the ethylene glycol-induced urolithiasis model. Standard drug used was Cystone. Several parameters were used including urinary volume, urine pH, urine analysis, and serum analysis to assess the activity. The results indicated that the administration of Unex to rats with ethylene glycol-induced lithiasis significantly reduced and prevented the growth of urinary stones (P < 0.01). Also, the treatment of lithiasis-induced rats by Unex restored all the elevated biochemical parameters (creatinine, uric acid, and blood urea nitrogen), restored the urine pH to normal, and increased the urine volume significantly (P < 0.01) when compared to the model control drug. This study supports the usage of Unex in urolithiasis and the utility could further be confirmed in other animal models.

Inhibitory effect of rutin and curcumin on experimentally-induced calcium oxalate urolithiasis in rats

BACKGROUND

Renal epithelial cell injury by reactive oxygen species is pre-requisite step in the pathogenesis of urolithiasis. Rutin and curcumin are polyphenolic compounds known to have antioxidant and anti-inflammatory activities, but their effect on urolithiasis is yet to be elucidated. In the present study, we have investigated the inhibitory effect of rutin and curcumin on calcium oxalate urolithiasis in Wistar albino rats.

METHODS

Calcium oxalate urolithiasis was induced experimentally by administration of 0.75% v/v ethylene glycol with 1% w/v ammonium chloride in drinking water for three days followed by only 0.75% v/v ethylene glycol for 25 days. Rutin (20 mg/kg body weight) and curcumin (60 mg/kg body weight) were given once daily for 28 days by oral route. After treatment period, calcium and oxalate levels in urine and kidney tissue homogenate were measured. Kidney was also used for histopathological examination.

RESULTS

Stone-induction with ethylene glycol and ammonium chloride resulted in elevated levels of calcium and oxalate in the urine and kidney sample, whereas supplementation of rutin and curcumin restored it near to normal. Histopathological study revealed minimum tissue damage and less number of calcium oxalate deposits in kidney of animal treated with rutin and curcumin as compared to calculi-induced animal.

CONCLUSION

The data suggest that the rutin and curcumin inhibits calcium oxalate urolithiasis. This effect is mediated possibly through a lowering of urinary concentration of stone forming constituents, anti-inflammatory and antioxidant effects.

Antiurolithiatic Activity of Whole-Plant Hydroalcoholic Extract of Pergularia daemia in Rats

The whole-plant, Pergularia daemia (Family: Asclepediaceae), extract (50% alcohol) was investigated for its antiurolithiatic and diuretic activity. Ethylene glycol (0.75% in water) feeding resulted in hyperoxaluria as well as increased renal excretion of calcium and phosphate. Alcoholic extract (400 mg/kg) of P. daemia was given orally in curative and preventive regimens over a period of 28 days. Supplementation with extract significantly (P < 0.001) lowered the urinary excretion and kidney retention levels of oxalate, calcium and phosphate. Furthermore, high serum levels of urea nitrogen, creatinine and uric acid were significantly (P < 0.001) reduced by the extract. The results were comparable with the standard drug, cystone (750 mg/kg). The reduction of stone-forming constituents in urine and their decreased kidney retention reduces the solubility product of crystallizing salts such as calcium oxalate and calcium phosphate, which could contribute to the antiurolithiatic property of the extract. The extract exhibited significant diuretic activity at dose of 400 mg/kg body weight as evidenced by increased total urine volume and the urine concentration of Na(+), and K(+). These findings affirm assertions made regarding the effectiveness of the extract of this plant against urinary pathologies in the Indian folk medicine.

Effect of ethanolic fruit extract of Cucumis trigonus Roxb. on antioxidants and lipid peroxidation in urolithiasis induced wistar albino rats

Urolithiasis was induced using ethylene glycol in wistar albino rats, the formation of calcium stones in the kidney results with the damage of antioxidant system. Ethanolic extract of Cucumis trigonus Roxb fruit of family Curcurbitaceae was used to treat urolithiasis. On this course, the extract also repairs the changes that happened in the enzymatic, non enzymatic antioxidants and lipid peroxidation in liver and kidney of urolithiasis induced rats. The results obtained from the analysis were compared at 5% level of significance using one way ANOVA. The results show that the ethanolic fruit extract has repaired the levels of antioxidants and malondialdehyde to their normal levels.

Biopotency of Acalypha indica Linn on Membrane Bound ATPases and Marker Enzymes urolithic Rats

The ethanolic extract of Acalypha indica was tested for its biopotency on membrane bound enzymes and marker enzymes in urolithiasis in male wistar albino rats. Calcium oxalate urolithiasis was induced by 0.75% ethylene glycol in drinking water for 30 days. There was a significant decrease in membrane bound enzymes such as Ca(2+) ATPase, Mg(2+) ATPase, Na(+)K(+) ATPase and marker enzymes Aspartate Transaminase (AST), Alanine Transaminase (ALT), Acid phosphatase (ACP) and Alkaline Phosphatase (ALP) in liver and kidney. The AST, ALT, ACP and ALP were increased in serum and urine of rats. Therapeutic treatment with plant extract (200mg/kg b.wt.dose(-1) day(-1) oral(-1)) has significantly ameliorated to near normalcy in the curative group. These results of the present study concluded that A. indica can play an important role in the prevention of disorders associated with kidney stone formation.

Uncoventional views on certain aspects of toxin-induced metabolic acidosis

This discussion will highlight the following 9 specific points that related to metabolic acidosis caused by various toxins. The current recommendation suggests that alcohol dehydrogenase inhibitor fomepizole is preferred to ethanol in treatment of methanol and ethylene glycol poisoning, but analysis of the enzyme kinetics indicates that ethanol is a better alternative. In the presence of a modest increase in serum osmolal gap (<30 mOsm/L), the starting dose of ethanol should be far less than the usual recommended dose. One can take advantage of the high vapor pressure of methanol in the treatment of methanol poisoning when hemodialysis is not readily available. Profuse sweating with increased water ingestion can be highly effective in reducing methanol levels. Impaired production of ammonia by the proximal tubule of the kidney plays a major role in the development of metabolic acidosis in pyroglutamic acidosis. Glycine, not oxalate, is the main final end product of ethylene glycol metabolism. Metabolism of ethylene glycol to oxalate, albeit important clinically, represents less than 1% of ethylene glycol disposal. Urine osmolal gap would be useful in the diagnosis of ethylene glycol poisoning, but not in methanol poisoning. Hemodialysis is important in the treatment of methanol poisoning and ethylene glycol poisoning with renal impairment, with or without fomepizole or ethanol treatment. Severe leucocytosis is a highly sensitive indicator of ethylene glycol poisoning. Uncoupling of oxidative phosphorylation by salicylate can explain most of the manifestations of salicylate poisoning.

Massive ethylene glycol ingestion treated with fomepizole alone-a viable therapeutic option

Fomepizole is used to treat and prevent toxicity from ethylene glycol poisoning. Treatment with fomepizole without hemodialysis in massive ethylene glycol ingestion has been rarely reported in the literature; however, published literature and practice guidelines recommend considering dialysis for ethylene glycol levels >50 mg/dL. We report a case of massive ethylene glycol ingestion resulting in the highest serum ethylene glycol concentration in a patient without ethanol co-ingestion who was treated with fomepizole and was not hemodialyzed. A 48-year-old male presented to the emergency department after reportedly ingesting >1 liter of antifreeze in an attempt at self-harm. He denied concomitant ethanol consumption. His initial presenting serum ethylene glycol level was 700 mg/dL, with normal renal function, and a metabolic acidosis with a high anion gap. One hour after presentation, he was started on intravenous fomepizole. Treatment with fomepizole continued until the patient's plasma ethylene glycol concentration was 16 mg/dL. His metabolic acidosis quickly resolved, he had no adverse reactions to the treatment, and his renal function remained normal. Ultimately, he was discharged to a psychiatric unit without sequelae. Published literature and practice guidelines suggests considering hemodialysis initiation in patients with an ethylene glycol level > 50 mg/dL. This recommendation is anecdotally, rather than evidence, based. With the potential risks inherent in hemodialysis, our case provides evidence that treatment with fomepizole without hemodialysis appears to be a viable alternative option in patients with even extremely high plasma ethylene glycol concentrations as long as their renal function is intact.

IN ETHYLENE GLYCOL INDUCED UROLITHIASIS IN MALE WISTAR ALBINO RATS

The ethanolic fruit extract of Pedalium murex to ethylene glycol intoxicated rats reverted the levels of the liver and kidney markers to near normal levels protecting liver and renal tissues from damage and also prevents the crystal retention in tissues. The levels of ACP, ALP, AST, ALT in serum andurine were significantly increased due to the damaged structural integrity of renal and hepatic cells causing the enzymes which are located in the cytoplasm to be released into the circulation. The levels of ACP and ALP, AST, ALT in renal and hepatic tissues of ethylene glycol induced rats might be due to leakage of the enzyme into the general circulation from the collateral circulation. LDH levels in serum, urine and tissues were increased on ethylene glycol intoxication is due to the oxalate induced renal and hepatic cellular damage.

Human oocyte vitrification: the permeability of metaphase II oocytes to water and ethylene glycol and the appliance toward vitrification

OBJECTIVE

To determine the permeability of human metaphase II oocytes to ethylene glycol and water in the presence of ethylene glycol, and to use this information to develop a method to vitrify human oocytes.

DESIGN

An incomplete randomized block design.

SETTING

A university-affiliated assisted reproductive center.

PATIENT(S)

Women undergoing assisted reproduction in the Center for Reproductive Medicine at Shandong University.

INTERVENTION(S)

Oocytes were exposed to 1.0 molar ethylene glycol in a single step and photographed during subsequent volume excursions.

MAIN OUTCOME MEASURE(S)

A two-parameter model was employed to estimate the permeability to water and ethylene glycol.

RESULT(S)

Water permeability ranged from 0.15 to 1.17 microm/(min.atm), and ethylene glycol permeability ranged from 1.5 to 30 microm/min between 7 degrees C at 36 degrees C. The activation energies for water and ethylene glycol permeability were 14.42 Kcal/mol and 21.20 Kcal/mol, respectively.

CONCLUSION(S)

Despite the lower permeability of human metaphase II oocytes to ethylene glycol compared with previously published values for propylene glycol and dimethylsulfoxide, methods to add and remove human oocytes with a vitrifiable concentration of ethylene glycol can be designed that prevent excessive osmotic stress and minimize exposure to high concentrations of this compound.

The ternary complex of Pseudomonas aeruginosa alcohol dehydrogenase with NADH and ethylene glycol

Pseudomonas aeruginosa alcohol dehydrogenase (PaADH; ADH, EC 1.1.1.1) catalyzes the reversible oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones, using NAD as coenzyme. We crystallized the ternary complex of PaADH with its coenzyme and a substrate molecule and determined its structure at a resolution of 2.3 A, using the molecular replacement method. The PaADH tetramer comprises four identical chains of 342 amino acid residues each and obeys ~222-point symmetry. The PaADH monomer is structurally similar to alcohol dehydrogenase monomers from vertebrates, archaea, and bacteria. The stabilization of the ternary complex of PaADH, the coenzyme, and the poor substrate ethylene glycol (k(cat) = 4.5 sec(-1); Km > 200 mM) was due to the blocked exit of the coenzyme in the crystalline state, combined with a high (2.5 M) concentration of the substrate. The structure of the ternary complex presents the precise geometry of the Zn coordination complex, the proton-shuttling system, and the hydride transfer path. The ternary complex structure also suggests that the low efficiency of ethylene glycol as a substrate results from the presence of a second hydroxyl group in this molecule.

Advances in the cryopreservation of mammalian oocytes and embryos: Development of ultrarapid vitrification

The cryopreservation of embryos has become a powerful tool in assisted reproduction in several mammalian species. Embryos are cryopreserved by slow freezing or by vitrification. However, consistently high survival has not been obtained in most oocytes and in some embryos. The main reasons for the low survival would be sensitivity to low temperatures, which leads to chilling injury, and low permeability of the cell membrane, which leads to the formation of intracellular ice. As a strategy aiming to overcome these injuries, modified vitrification methods have been devised in which the cooling and warming rate is markedly increased by minimizing the volume of the solution and the container. The modified methods use electron microscope grids, open-pulled straws, cryoloops, or container-less microdrops. In this article, recent developments in the ultrarapid vitrification of mammalian oocytes and embryos are reviewed based on the understanding of the mechanisms of cell injury in cryopreservation. (Reprod Med Biol 2002; 1: 1-9).

Enzyme assay in microsomes below zero degrees

Reactions of a membrane-bound multienzyme complex (electron-transport chain of rat-liver microsomes) suspended in aqueous-organic solvent used as antifreeze at temperatures below 0 degrees were studied. In the presence of a relatively high concentration of ethylene glycol, electron transfer can still be observed and some individual and sequential enzyme assays can be performed over a wide range of temperatures below 0 degrees .