Disposition of glycolic acid into the embryo following oral administration of ethylene glycol during placentation in the rat and rabbit

In order to evaluate the role of the placenta in the etiology of ethylene glycol (EG) developmental toxicity, the distribution of EG and its main metabolites, glycolic acid (GA) and oxalic acid (OX), into the conceptus was determined at the beginning and completion of placentation in the rat and rabbit. Two groups (n = 28) of timed-pregnant Wistar rats were administered EG (1000 mg/kg bw/day, oral gavage) from gestation day (GD) 6 to either GD 11 or GD 16; similarly, two groups (n = 28) of timed-pregnant New Zealand White rabbits were administered EG from GD 6 to either GD 10 or GD 19. Four animals from each group were sacrificed at 1, 3, 6, 9, 12, 18, or 24 h after the final administration, and maternal blood, extraembryonic fluid, and embryonic tissue were removed for analysis of EG, GA, and OX. The three analytes were predominantly cleared from all compartments in both species within 24 h. Neither EG nor OX preferentially accumulated into the conceptus compartments, compared with the maternal blood, in either species. Critically, GA was preferentially accumulated from the maternal blood only into the rat embryo at GD 11, but not at GD 16 and not into the rabbit embryo at either GD 10 or GD 19. The accumulation of GA into the rat embryo, and its decline over the course of placentation, is discussed in relation to the expression of monocarboxylate transporter isoforms across the syncytiotrophoblast.

The preventive effects of Ulva lactuca aqueous extract, ulvan polysaccharides and atorvastatin on ethylene glycol-induced hyperoxaluria

OBJECTIVE

Kidney stones are a common complication of hyperoxaluria. The aim of this study is to investigate the protective and preventive effects of Ulva lactuca aqueous extract, ulvan polysaccharides and atorvastatin on ethylene glycol-induced hyperoxaluria.

MATERIALS AND METHODS

Male Wistar rats between 110 and 145 g in weight were used in the study, Ulva lactuca aqueous extract and polysaccharides were prepared. The male albino rats were supplemented with 0.75 percent ethylene glycol (v/v) in their drinking water for six weeks to induce hyperoxaluria. Ulvan infusions (100 mg/kg body weight), ulvan polysaccharides (100 mg/kg body weight), and atorvastatin (two milligrams/kg body weight) to treat hyperoxaluric rats for four weeks (every other day) were used. Weight loss, serum creatinine, serum urea, serum uric acid, serum oxalate, kidney oxalate, kidney lipid peroxidation, and kidney DNA fragmentation and kidney histopathological studies were done.

RESULTS

Weight loss, rise of serum creatinine, serum urea, serum uric acid, serum oxalate, kidney oxalate, kidney lipid peroxidation, and kidney DNA fragmentation were all shown to be prevented by the addition of atorvastatin, polysaccharides, or aqueous extract, respectively. Catalase (CAT) activity, glutathione peroxidase (GPX) activity, glutathione-S-transferase (GST) activity, and histopathological perturbations were all significantly reduced by the medicines that were studied.

CONCLUSIONS

Hyperoxaluria caused by ethylene glycol may be prevented by a combination of Ulva lactuca aqueous extract, ulvan polysaccharides, and atorvastatin. A reduction in renal oxidative stress and an improvement of the antioxidant defense system may be responsible for these protective benefits. However, Ulva lactuca infusion and ulvan polysaccharides need to be studied further in humans, in order to determine their efficacy and safety.

In vivo investigation of the inhibitory effect of Peganum harmala L. and its major alkaloids on ethylene glycol-induced urolithiasis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Peganum harmala L. is a traditional medicinal plant used for centuries in folk medicine. It has a wide array of therapeutic attributes, which include hypoglycemic, sedative, anti-inflammatory, and antioxidant properties. The fruit decoction of this plant was claimed by Avicenna as traditional therapy for urolithiasis. Also, P. harmala seed showed a clinical reduction in kidney stone number and size in patients with urolithiasis.

AIM OF THE STUDY

In light of the above-mentioned data, the anti-urolithiatic activities of the seed extracts and the major β-carboline alkaloids of P. harmala were investigated.

MATERIALS AND METHODS

Extraction, isolation, and characterization of the major alkaloids were performed using different chromatographic and spectral techniques. The in vivo anti-urolithiatic action was evaluated using ethylene glycol (EG)-induced urolithiasis in rats by studying their mitigating effects on the antioxidant machinery, serum toxicity markers (i.e. nitrogenous waste, such as blood urea nitrogen, uric acid, urea, and creatinine), minerals (such as Ca, Mg, P, and oxalate), kidney injury marker 1 (KIM-1), and urinary markers (i.e. urine pH and urine output).

RESULTS

Two major alkaloids, harmine (P1) and harmalacidine HCl (P2), were isolated and in vivo evaluated alongside the different extracts. The results showed that P. harmala and its constituents/fractions significantly reduced oxidative stress at 50 mg/kg body weight, p.o., as demonstrated by increased levels of glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), and catalase (CAT) in kidney homogenate as compared to the EG-treated group. Likewise, the total extract, pet. ether fraction, n-butanol fraction, and P1, P2 alleviated malondialdehyde (MDA) as compared to the EG-treated group. Serum toxicity markers like blood urea nitrogen (BUN), creatinine, uric acid, urea, kidney injury molecule-1 (Kim-1), calcium, magnesium, phosphate, and oxalate levels were decreased by total extract, pet. ether fraction, n-butanol fraction, P1, and P2 as compared to the EG-treated group. Inflammatory markers like NFκ-B and TNF-α were also downregulated in the kidney homogenate of treatment groups as compared to the EG-treated group. Moreover, urine output and urine pH were significantly increased in treatment groups as compared to the EG-treated group deciphering anti-urolithiatic property of P. harmala. Histopathological assessment by different staining patterns also supported the previous findings and indicated that treatment with P. harmala caused a gradual recovery in damaged glomeruli, medulla, interstitial spaces and tubules, and brown calculi materials as compared to the EG-treated group.

CONCLUSION

The current research represents scientific evidence on the use of P. harmala and its major alkaloids as an effective therapy in the prevention and management of urolithiasis.

Multiple cryoprotectant toxicity model for vitrification solution optimization

Vitrification is a promising cryopreservation technique for complex specimens such as tissues and organs. However, it is challenging to identify mixtures of cryoprotectants (CPAs) that prevent ice formation without exerting excessive toxicity. In this work, we developed a multi-CPA toxicity model that predicts the toxicity kinetics of mixtures containing five of the most common CPAs used in the field (glycerol, dimethyl sulfoxide (DMSO), propylene glycol, ethylene glycol, and formamide). The model accounts for specific toxicity, non-specific toxicity, and interactions between CPAs. The proposed model shows reasonable agreement with training data for single and binary CPA solutions, as well as ternary CPA solution validation data. Sloppy model analysis was used to examine the model parameters that were most important for predictions, providing clues about mechanisms of toxicity. This analysis revealed that the model terms for non-specific toxicity were particularly important, especially the non-specific toxicity of propylene glycol, as well as model terms for specific toxicity of formamide and interactions between formamide and glycerol. To demonstrate the potential for model-based design of vitrification methods, we paired the multi-CPA toxicity model with a published vitrification/devitrification model to identify vitrifiable CPA mixtures that are predicted to have minimal toxicity. The resulting optimized vitrification solution composition was a mixture of 7.4 molal glycerol, 1.4 molal DMSO, and 2.4 molal formamide. This demonstrates the potential for mathematical optimization of vitrification solution composition and sets the stage for future studies to optimize the complete vitrification process, including CPA mixture composition and CPA addition and removal methods.

Calcium Oxalate Monohydrate is Associated with Endothelial Cell Toxicity But Not with Reactive Oxygen Species Accumulation

One characteristic of ethylene glycol overdose is a cardiopulmonary syndrome including hypertension and pulmonary edema with pathology indicating damage to the endothelium of heart, lung and brain vessels. The mechanism of the cardiopulmonary toxicity is unknown, but has been linked with accumulation of the metabolite calcium oxalate monohydrate (COM) in the endothelium. These studies have evaluated the hypothesis that COM or the oxalate ion produces endothelial damage in vitro and that damage is linked with induction of reactive oxygen species (ROS). In cultured human umbilical vein endothelial cells (HUVEC), COM, but not the oxalate ion, produced cytotoxicity in a dose- and time-dependent manner. Using three ROS-sensitive dyes, HUVEC exposed to COM did not significantly increase ROS production. Additionally, co-treatment with three antioxidants that operate by different mechanisms did not reduce COM cytotoxicity. As such, an increase in ROS production does not explain cell death in endothelial cells. Aluminum citrate, uniquely among citrate compounds, significantly reduced COM cytotoxicity to endothelial cells and thus may act as an adjunct therapy for ethylene glycol poisoning to reduce endothelial damage. These results imply that accumulation of COM in endothelial cells is an important aspect of the cardiopulmonary toxicity from ethylene glycol.

[Ethylene glycol intoxication requires a multidisciplinary approach]

Cheap and easy to access, ethylene glycol is used in the synthesis of antifreezes. Intoxication has potentially irreversible morbid consequences. Ingestion of a small amount can lead to death. Due to its ubiquitous distribution and potential complications, it is of paramount importance for the practitioner to recognize its manifestations and metabolic complications in order to implement its therapy in partnership with the nephrologist and the intensivist. A successful treatment depends on rapid and multidisciplinary management, as reviewed in this article.

Acute and subacute toxicity evaluation of calcium carbide and ethylene glycol in Wistar albino rats

Background Naturally ripened fruits play a vital role in human nutrition. Under certain conditions, synthetic chemicals like calcium carbide (CaC2) and ethylene glycol (EG) are being freely used illegally in India and other countries for fruit ripening without serious concern on its toxic effects. This preclinical study evaluated the toxicity on different organs after the exposure of industrial-grade CaC2 and EG to the rats. Methods Acute toxicity was induced by the oral administration of a single dose of chemicals to the rats, and their morbidity and mortality were monitored. For subacute study, different organs of animals were analyzed biochemically and histologically after the exposure of low doses of chemicals for 30 days. Results At an acute dose of 5 mg/kg body weight of CaC2, 85% of the animals were found dead within 14 days; however, no mortality was observed following EG administration. At subacute doses, RBC and hemoglobin levels were found to be declined (p < 0.01), whereas total WBC and platelet counts, especially lymphocytes, were elevated remarkably (p < 0.01). Total protein, albumin, and urea were also found to be increased (p < 0.01). Histopathological observations support the toxicity in rats at higher doses of CaC2 and EG. Conclusions The study revealed that the artificial fruit-ripening agents like CaC2 and EG cause toxic effects on the internal organs of rats. The subsequent inflammatory response might have weakened the immune system. This in turn suggests the requisite for urgent measures to regulate the use of harmful synthetic agents in fruit ripening.

Genetic suppression of cryoprotectant toxicity

We report here a new, unbiased forward genetic method that uses transposon-mediated mutagenesis to enable the identification of mutations that confer cryoprotectant toxicity resistance (CTR). Our method is to select for resistance to the toxic effects of M22, a much-studied whole-organ vitrification solution. We report finding and characterizing six mutants that are resistant to M22. These mutants fall into six independent biochemical pathways not previously linked to cryoprotectant toxicity (CT). The genes associated with the mutations were Gm14005, Myh9, Nrg2, Pura, Fgd2, Pim1, Opa1, Hes1, Hsbp1, and Ywhag. The mechanisms of action of the mutations remain unknown, but two of the mutants involve MYC signaling, which was previously implicated in CT. Several of the mutants may up-regulate cellular stress defense pathways. Several of the M22-resistant mutants were also resistant to dimethyl sulfoxide (Me2SO), and many of the mutants showed significantly improved survival after freezing and thawing in 10% (v/v) Me2SO. This new approach to overcoming CT has many advantages over alternative methods such as transcriptomic profiling. Our method directly identifies specific genetic loci that unequivocally affect CT. More generally, our results provide the first direct evidence that CT can be reduced in mammalian cells by specific molecular interventions. Thus, this approach introduces remarkable new opportunities for pharmacological blockade of CT.

Outcomes after toxic alcohol poisoning: a systematic review protocol

BACKGROUND

Toxic alcohols have been implicated in accidental ingestions and intentional exposures. Recognition of toxic alcohol poisoning is challenging. The main treatment modalities include antidotes with alcohol dehydrogenase inhibitors and dialysis. Current guidelines exist for both methanol and ethylene glycol intoxication. However, treatment consensus related to other toxic alcohols is limited. Furthermore, uncertainties regarding thresholds for when to initiate antidotes and dialysis persist. As a consequence, variations exist in the interventions utilized for management of all toxic alcohol poisonings. To our knowledge, no prior systematic review of clinical outcomes of toxic alcohols exists. The objective of this study is to summarize existing evidence on short- and long-term outcomes of patients following toxic alcohol poisonings, including methanol, ethylene glycol, isopropanol, propylene glycol, and diethylene glycol.

METHODS

A literature search in PubMed, MEDLINE, and EMBASE will be performed based on pre-determined criteria. There will be no restrictions on publication dates or languages. The search will be supplemented by manual scan of bibliographies of eligible studies and gray literature assessment. Observational studies and clinical trials will be included in this review. Once eligible studies have been selected based on pre-specified criteria, two investigators will extract relevant data independently and perform quality assessment per validated tools. A pooled analysis of mortality and short- and long-term secondary outcomes will be performed. Pre-specified subgroup analyses will be performed according to the type of toxic alcohol intoxication, mode of renal replacement therapy, and medical interventions received. A meta-analysis will be performed if three or more studies with similar populations, type of toxic alcohol poisoning, and outcome measures, as well as adequate quality, are identified. This review will be reported according to the recommendations of the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Statement.

DISCUSSION

This systematic review aims to synthesize current evidence in the short- and long-term outcomes of post-toxic alcohol poisoning. The results will enhance the understanding of patient morbidity and mortality after toxic alcohol poisoning, help inform uniform concrete management guideline development, identify gaps in the current state of knowledge, and provide evidence to help implement post-treatment follow-up.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018101955.

Assessment of ethylene glycol diacetate as an alternative carrier for use in agrochemical emulsifiable concentrate formulation

The conventional emulsifiable concentrate (EC) formulation contains a large amount of aromatic solvents, which causes adverse effects to both the environment and human health due to the toxicity of the solvents. Here, we developed a 2.5% lambda-cyhalothrin EC formulation with ethylene glycol diacetate (EGDA) as the solvent, and the developed formulation serves as an environmental-friendly alternative to overcome the adverse effects of aromatic solvents. The physicochemical characterizations, wettability properties, phytotoxicity and bioassays of the EGDA-EC formulation were systematically investigated and compared with that of the EC formulation with xylene as the solvent. The results showed that both EC formulations had excellent emulsion properties and storage stabilities. Additionally, the EGDA-EC formulation possessed a higher flash point (96 °C), indicating safer production, storage and transport. The retentions of the EGDA-EC sample on leaves were 1.22-1.46-fold higher than that of the xylene-EC sample, and the EGDA-EC also exhibited lower surface tensions and contact angles, which would benefit decreasing drift-off and improving utilization. Furthermore, the bioassays demonstrated that the EGDA-EC formulation had lower acute toxicity to aquatic organisms and higher control efficacy to target insects compared with the xylene-EC formulation. Therefore, EGDA is a promising carrier for oil-soluble agrochemicals to improve their application performance and reduce their adverse effects.

Toxic alcohol ingestion: prompt recognition and management in the emergency department [digest]

Identifying patients with potential toxic alcohol exposure and initiating appropriate management is critical to avoid significant patient morbidity. Sources of toxic alcohol exposure include ethylene glycol, methanol, diethylene glycol, propylene glycol, and isopropanol. Treatment considerations include the antidotes fomepizole and ethanol, and hemodialysis for removal of the parent compound and its toxic metabolites. Additional interventions include adjunctive therapies that may improve acidosis and enhance clearance of the toxic alcohol or metabolites. This issue reviews common sources of alcohol exposure, basic mechanisms of toxicity, physical examination and laboratory findings that may guide rapid assessment and management, and indications for treatment. [Points & Pearls is a digest of Emergency Medicine Practice].

Regulation of urinary crystal inhibiting proteins and inflammatory genes by lemon peel extract and formulated citrus bioflavonoids on ethylene glycol induced urolithic rats

The objective of this study is to check the regulation of crystal matrix proteins and inflammatory mediators by citrus bioflavonoids (CB) and Lemon peel (LP) extract in hyperoxaluric rats. The animals were divided into six groups with 6 animals each. Group 1: Control, Group 2: Urolithic (Ethylene glycol (EG)-0.75%); Group 3 & 5: Preventive study (EG + CB (20 mg/kg body weight) and LP (100 mg/kg body weight) extract administration from 0th-7th week) respectively; Group 4 & 6: Curative study (EG + CB and LP extract administration from 4th-7th week) respectively by oral administration. Urinary lithogenic factors (Calcium, oxalate, phosphate and citrate) were normalized in CB & LP supplemented rats, while serum parameters revealed the nephroprotective nature of the intervening agents compared to urolithic rats (p < 0.001). Immunoblotting studies showed significantly increased expression of THP, osteopontin and transferrin in kidneys of urolithic rats (p < 0.001), while preventive and curative study showed near normal expression of these proteins. Expression of NF-κB, TNF-α and IL-6 were raised significantly (p < 0.001), while a very minimal increase in MCP-1 expression was observed in urolithic rats compared to control. Hence, supplementation of CB and LP reduced the crystal promoting factors and provides protection from crystal induced renal damage.

Beneficial effect of Citrus limon peel aqueous methanol extract on experimentally induced urolithic rats

CONTEXT

Citrus limon (L.) Burm.f. (Rutaceace) is a commonly available fruit variety with high medicinal and industrial values.

OBJECTIVE

Lemon peel (LP) extract was studied as a potent preventive and curative agent for experimentally induced hyperoxaluric rats.

MATERIALS AND METHODS

Gas chromatography-mass spectrometry (GC-MS) analyses and toxicity study were performed for aqueous methanol LP extract. Twenty-four Wistar rats were segregated into four groups. Group 1: Control; Group 2: Urolithic (ethylene glycol (EG) - 0.75%); Group 3: Preventive study (EG + LP extract administration from 0th to 7th week); Group 4: Curative study (EG + LP extract administration from 4th to 7th week). Animals received LP extract daily by oral administration (100 mg/kg body weight) for 7 weeks.

RESULTS AND DISCUSSION

GC-MS analyses revealed that compound 6 was abundant in the LP extract (32%) followed by compound 1 (∼21%). The LD50 value of LP extract was found to be >5000 mg/kg of body weight. Urolithic rats showed significantly higher urinary calcium and oxalate (4.47 ± 0.44 and 18.86 ± 0.55 mg/24 h, respectively) excretion compared with control and experimental rats. Renal function parameters like urea (84 ± 8.5 and 96.1 ± 3.6 mg/dL), creatinine (1.92 ± 0.27 and 1.52 ± 0.22 mg/dL), and urinary protein (2.03 ± 0.02 and 2.13 ± 0.16 mg/24 h) were also reduced by LP extract (p < 0.001) and corroborated with tissue analyses (SOD, catalase, and MDA levels) and histological studies in normal and experimental animals. Immunohistochemical staining of THP and NF-κB in urolithic animals showed elevated expression than the control, while LP extract suppressed the expression of these proteins.

CONCLUSION

In conclusion, lemon peel is effective in curing kidney stone disease and also can be used to prevent the disease and its recurrence.

Assessing the toxicity and biodegradability of deep eutectic solvents

Deep eutectic solvents (DESs) have emerged as a new type of promising ionic solvents with a broad range of potential applications. Although their ecotoxicological profile is still poorly known, DESs are generally regarded as "green" because they are composed of ammonium salts and H-bond donors (HBDs) which are considered to be eco-friendly. In this work, cholinium-based DESs comprised of choline chloride (ChCl) and choline acetate (ChAc) as the salt and urea (U), acetamide (A), glycerol (G) and ethylene glycol (EG) as the HBD were evaluated for their toxic effects on different living organisms such as Escherichia coli (a bacterium), Allium sativum (garlic, a plant) and hydra (an invertebrate), and their biodegradabilities were assessed by means of closed bottle tests. These DESs possessed an anti-bacterial property and exhibited inhibitory effects on the test organisms adopted, depending on the composition and concentration of the DES. The mechanism for the impact of DESs and their components on different living organisms can be associated to their interactions with the cellular membranes. Not all DESs can be considered readily biodegradable. By extending the limited knowledge about the toxicity and biodegradation of this particular solvent family, this investigation on DESs provides insight into our structure-based understanding of their ecotoxicological behavior.

TOXICITY OF CRYOPROTECTIVE AGENTS AND SIGNALING OF INSULIN-LIKE GROWTH FACTOR IN HEN CLAM (MACTRA CHINENSIS) EMBRYOS

BACKGROUND

Signaling of Insulin-like growth factor-I (IGF-I) is involved in development, growth, reproduction and aging of organisms.

OBJECTIVE

The work investigated the toxicity of glycerol, dimethyl sulfoxide (DMSO), and ethylene glycol (EG) to hen clam (Mactra chinensis) embryos, as well as the possible role of the insulin-like growth factor-I (IGF-I) during the development and growth of embryos after freeze.

MATERIALS AND METHODS

Effects of glycerol, DMSO and EG at different concentrations were tested. The relationship between larval viability and signaling of IGF-I receptor after cryoprotective treatment and/or freezing was examined using immuno-blot analysis.

RESULTS

Glycerol had the highest toxicity, followed by DMSO or EG. No embryo survived freeze and thaw without CPAs. After freeze, the activation of the IGF-I signaling pathway, including the IGF-I receptor (IGF-IR) β-subunit, could be detected in freeze-thawed embryos. The level of IGF-IR expression was very weak in freeze-thawed embryos.

CONCLUSION

The survival and developmental rate of embryos was closely related to CPA concentration. IGF-IR was activated and regulated the downstream IGF-I signaling in embryos. The reduced activation of IGF-IR could be related to the death of hen clam embryos.

[Metabolic therapy of nephrolithiasis in two different rat models of kidney disease]

108 albino male rats were used in two experimental rat models reproducing urolithiasis for the assessment of metabolic drug medicine Remaxol nephroprotective effect upon the development of this disease. "Ethyleneglycol" model consisted of adding 1% ethylene glycol solution in drinking water for 37 days and "fructose-induced" one--of adding 10% fructose solution in drinking water for the same period. Therapy included a 10-day course of daily i.v. injections of Remaxol (14 ml/kg). Both experimental models were successful in producing urolithiasis with considerable disturbances in the structure and functioning of kidneys up to revealing microconcrement formation. The "ethyleneglycol" model proved to cause maximum changes while the "Fructose-induced" model--only moderate ones. Metabolic correction of these changes was successful in nephroprotection effectively normalizing kidney functions and the total protein concentration, eliminating hyperglycemia and reducing creatinine and urea blood plasma concentration in both rat experimental models.

Influence of the toxicity of cryoprotective agents on the involvement of insulin-like growth factor-I receptor in surf clam (Spisula sachalinensis) larvae

BACKGROUND

The signaling of insulin-like growth factor-I (IGF-I) is involved in the development, growth, reproduction and aging of vertebrates. However, few studies have investigated the involvement of IGF-I during states of extreme shock, such as those induced by potently toxic cryoprotective agents (CPAs) or low temperature conditions, in bivalves.

OBJECTIVE

We investigated the toxicity of CPAs and the potential relationship between larval viability and the IGF-I receptor (IGF-IR) after treatment with CPAs or freezing in surf clam (Spisula sachalinensis) larvae.

MATERIALS AND METHODS

The umbo larvae and different concentrations of CPAs (dimethyl sulfoxide, DMSO; ethylene glycol, EG) were used to investigate the toxicity of CPAs and the vitrification of surf clam larvae. The relationship between larval viability and the IGF-I receptor (IGF-IR) after treatment with CPAs or freezing was investigated using immunoblot analysis.

RESULTS

An increase in concentration greater than 4M DMSO was fatal in larvae; however, 5M EG combined with a mixture of CPAs had no harmful effects. Moreover, live larvae immersed in a 5M EG solution remained intact and maintained their normal shape and organs. However, even though the larvae survived the CPA toxicity test, none of the vitrified larvae survived. After immersion into CPAs and vitrification, 97-kDa IGF-IR ß-subunits could be detected in all larvae; but tyrosine phosphorylation of the intracellular β-subunits was detected only in the control and live groups.

CONCLUSION

IGF-IR was activated in the umbo larvae but not in dead surf clam larvae treated with CPA and frozen. Activation of IGF-IR has relevance to the umbo larval stage in live surf clams treated with CPAs.

Prolonged renal failure in the course of atypical ethylene glycol intoxication

Ethylene glycol poisoning is not an uncommon cause of an acute renal injury. In this paper we present case of prolonged renal failure in the course of ethylene glycol intoxication. Due to the low dose of ingested ethylene glycol and concomitant ethanol consumption, the neurodepressive phase of the intoxication was rather mild and patient presented to the hospital on the ninth day after poisoning with established renal failure. The diagnosis of the specific cause of renal injury was facilitated by the renal biopsy.

[Preparation, characterization and Calu-3 cellular uptake of three kinds of poly(b-benzyl-L-amino)block-poly(ethylene glycol) nanoparticles]

The aim of this paper is to compare the cytotoxicity and cellular uptake efficiency of three kinds of poly(b-benzyl-L-amino) block-poly(ethylene glycol) nanoparticles (PXA-PEG-NPs) using Calu-3 cells, and select one as a nasal drug delivery vector for curcumin (Cur). Poly(gamma-benzyl-L-glutamate) block-poly(ethylene glycol) nanoparticles (PBLG-PEG-NPs), poly(gamma-benzyl-L-lysine) block-poly(ethyleneglycol) nanoparticles (PZLL-PEG-NPs) and poly(gamma-benzyl-L-aspartate) block-poly(ethylene glycol) nanoparticles (PBLA-PEG-NPs) were prepared by emulsion-solvent evaporation method. MTT assays were used to evaluate the cytotoxicity of PXA-PEG-NPs against Calu-3 cells. The cellular uptake of nanoparticles was visualized by an inverted fluorescence microscope and quantified by a flow cytometer. The results indicated that even at high concentration of 2 mg x mL(-1) the three nanoparticles had no cytotoxicity on Calu-3 cells. Compared to the curcumin solution, the three curcumin-loaded PXA-PEG-NPs showed significantly higher cellular uptake efficiency on Calu-3 cells (at equal concentration of curcumin with 5 microg x mL(-1) Cur solution), PBLG-PEG-NPs group was the highest. The cellular uptake increased with incubation time, and has positive correlation with nanoparticle concentration. In brief, PXA-PEG-NPs are conducive to delivery Cur into cells, and PBLG-PEG-NPs might be provided as a good nasal drug delivery carrier.

The protection of polysaccharide from the Brown Seaweed Sargassum graminifolium against ethylene glycol-induced mitochondrial damage

The aim of the present study is to evaluate the protective effect of polysaccharide from the Brown Seaweed Sargassum graminifolium (SGP) on ethylene glycol-induced kidney damage and the mechanism of SGP-mediated protection. Mitochondrial lipid peroxidation, mitochondrial swelling, the activity of succinate dehydrogenase (SDH), ATPases and mitochondrial antioxidant enzymes was observed in hyperoxaluric rats. Administration of SGP (25, 100 and 400 mg·kg-1, intragastrically) increased the activities of antioxidant enzymes, SDH and Na+/K+-ATPases, Ca2+-ATPases, Mg2+-ATPases, also decreased mitochondrial lipid peroxidation and mitochondrial swelling. SGP exhibited a protective effect by improving antioxidant enzymes and restoring mitochondrial dysfunction in the kidney of hyperoxaluric rats. It may be used as a promising therapeutic agent to provide superior renal protection.

Matrix Gla protein is involved in crystal formation in kidney of hyperoxaluric rats

BACKGROUND

Matrix Gla protein (MGP) is a molecular determinant regulating vascular calcification of the extracellular matrix. However, it is still unclear how MGP may be involved in crystal formation in the kidney of hyperoxaluric rats.

METHODS

Male Sprague-Dawley rats were divided into the hyperoxaluric group and control group. Hyperoxaluric rats were administrated by 0.75% ethylene glycol (EG) for up to 8 weeks. Renal MGP expression was detected by the standard avidin-biotin complex (ABC) method. Renal crystal deposition was observed by a polarizing microscope. Total RNA and protein from the rat kidney tissue were extracted. The levels of MGP mRNA and protein expression were analyzed by the real-time polymerase chain reaction (RT-PCR) and Western blot.

RESULTS

Hyperoxaluria was induced successfully in rats. The MGP was polarly distributed, on the apical membrane of renal tubular epithelial cells, and was found in the ascending thick limbs of Henle's loop (cTAL) and the distal convoluted tubule (DCT) in hyperoxaluric rats, its expression however, was present in the medullary collecting duct (MCD) in stone-forming rats. Crystals with multilaminated structure formed in the injurious renal tubules with lack of MGP expression.MGP mRNA expression was significantly upregulated by the crystals' stimulations.

CONCLUSION

Our results suggested that the MGP was involved in crystals formation by the continuous expression, distributing it polarly in the renal tubular cells and binding directly to the crystals.

Cryopreservation of Greenshell™ mussel (Perna canaliculus) trochophore larvae

The Greenshell™ mussel (Perna canaliculus) is the main shellfish species farmed in New Zealand. The aim of this study was to evaluate the effects of cryoprotectant concentration, loading and unloading strategy as well as freezing and thawing method in order to develop a protocol for cryopreservation of trochophore larvae (16-20 h old). Toxicity tests showed that levels of 10-15% ethylene glycol (EG) were not toxic to larvae and could be loaded and unloaded in a single step. Through cryopreservation experiments, we designed a cryopreservation protocol that enabled 40-60% of trochophores to develop to D-larvae when normalized to controls. The protocol involved: holding at 0 °C for 5 min, then cooling at 1 °C min⁻¹ to -10 °C, holding for a further 5 min, then cooling at 0.5 °C min⁻¹ to -35 °C followed by a 5 min hold and then plunging into liquid nitrogen. A final larval rearing experiment of 18 days was conducted to assess the ability of these frozen larvae to develop further. Results showed that only 2.8% of the frozen trochophores were able to develop to competent pediveligers.

Curative treatment with extracts of Bombax ceiba fruit reduces risk of calcium oxalate urolithiasis in rats

CONTEXT

Drawbacks of presently available treatments for urolithiasis necessitate finding the treatment of hyperoxaluria specifically aimed at reduction in oxalate excretion. Interestingly, many Indian tribes use Bombax ceiba L. (Bombacaceae) fruits as a traditional medicine for the treatment of urinary stones.

OBJECTIVE

The present study investigated the efficacy of B. ceiba fruit extracts as curative agents in experimentally induced calcium oxalate urolithiatic rats.

MATERIALS AND METHODS

Calcium oxalate lithiasis was induced in rats by oral administration of 0.75% ethylene glycol for 14 consecutive days. Treatments with aqueous and ethanol extract of B. ceiba fruit (400 mg/kg body weight) was performed in the same manner for further 14 consecutive days. Cystone (750 mg/kg body weight) was used as reference antiurolithiatic drug. The urinary excretion and kidney deposition of offending salt components, and serum biochemical parameters were investigated.

RESULTS

Oral administration of ethylene glycol resulted in hyperoxaluria and increased renal excretion of calcium and phosphate. However, supplementation with aqueous and ethanol extracts of B. ceiba fruit significantly (p < 0.05) reduced the elevated urinary oxalate, showing a regulatory action on endogenous oxalate synthesis. The increased deposition of stone forming constituents in kidneys of calculogenic rats was also significantly lowered with curative treatment of aqueous and ethanol extract.

DISCUSSION AND CONCLUSION

The results indicate that the fruit of B. ceiba is endowed with lithontriptic activity warranting further development for curative treatment of urolithiasis.

Bergenia ciliata extract prevents ethylene glycol induced histopathological changes in the kidney

The present investigation is an attempt to evaluate the effect of Bergenia ciliata extract on kidney of ethylene glycol induced urolithiasis in adult female Wistar rats. The hydro-alcoholic extract of Bergenia ciliata/standard drug cystone were administrated simultaneously at a dose of 150 and 300 mg/kg body weight/day, p.o. along with ethylene glycol (0.75% v/v) for 28 days. Significant changes were observed in body weight and absolute organ weight of ethylene glycol treated rats. Also histopathological results showed disrupted renal parenchyma, degenerative changes in glomeruli and focal calcification in glomerulo-tubular structures in ethylene glycol treated animals. Administration of Bergenia ciliata extract/cystone along with ethylene glycol showed significant protective effect in body weight and organ weight with few stray areas of calcifications in glomeruli. Moreover, Bergenia ciliata extract shows higher renoprotective index than cystone at the same dose level.

Assessing the toxic effects of ethylene glycol ethers using Quantitative Structure Toxicity Relationship models

Experimental determination of toxicity profiles consumes a great deal of time, money, and other resources. Consequently, businesses, societies, and regulators strive for reliable alternatives such as Quantitative Structure Toxicity Relationship (QSTR) models to fill gaps in toxicity profiles of compounds of concern to human health. The use of glycol ethers and their health effects have recently attracted the attention of international organizations such as the World Health Organization (WHO). The board members of Concise International Chemical Assessment Documents (CICAD) recently identified inadequate testing as well as gaps in toxicity profiles of ethylene glycol mono-n-alkyl ethers (EGEs). The CICAD board requested the ATSDR Computational Toxicology and Methods Development Laboratory to conduct QSTR assessments of certain specific toxicity endpoints for these chemicals. In order to evaluate the potential health effects of EGEs, CICAD proposed a critical QSTR analysis of the mutagenicity, carcinogenicity, and developmental effects of EGEs and other selected chemicals. We report here results of the application of QSTRs to assess rodent carcinogenicity, mutagenicity, and developmental toxicity of four EGEs: 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, and 2-butoxyethanol and their metabolites. Neither mutagenicity nor carcinogenicity is indicated for the parent compounds, but these compounds are predicted to be developmental toxicants. The predicted toxicity effects were subjected to reverse QSTR (rQSTR) analysis to identify structural attributes that may be the main drivers of the developmental toxicity potential of these compounds.

How good are clinical chemistry laboratories at analysing ethylene glycol?

The results of an external proficiency test of clinical chemistry laboratories in Sweden when the target analyte was ethylene glycol (EG) are presented. Specimens of plasma were spiked with EG (10% w/v) to give assigned concentrations ranging from 5 to 50 mmol/L. Over a period of 6 years, two control specimens of plasma were sent for analysis on 21 occasions to between 14 and 20 participating laboratories as a declared proficiency trial. The analytical precision between and within laboratories was determined by spiking the plasma specimens with the same concentration of EG so that the results reported back could be considered a duplicate determination. On one occasion propylene glycol (PG) was substituted for EG without informing the participants. The standard deviation (SD) within laboratories expressed as the coefficient of variation (CV) was 4.5% compared with 11.4% between laboratories. Results reported by laboratories using gas chromatography (GC) were in good agreement with those when an enzymatic method was used. The between-laboratory SD increased with concentration of EG in the specimen and at a mean concentration of 18 mmol/L, the pooled SD was 4.11 mmol/L (CV = 23%). Four laboratories reported finding EG in plasma when PG was the diol present; three laboratories used an enzymatic method and one used GC. Clinical laboratories that provide a toxicology service should regularly participate in external quality assurance schemes that include low-molecular-weight alcohols such as EG. Efforts should be made to standardize the analytical methods used for toxicological analysis.

Studies on cryoprotectant toxicity to early stage zebrafish (Danio rerio) ovarian follicles

Cryoprotectants are substances characterised by their ability to reduce cryoinjury of biological materials during the course of freezing. Unfortunately cryoprotectants can be toxic for cells. The aim of this study is to investigate the toxicity of cryoprotectants to early stage ovarian follicles of zebrafish (Danion rerio) before designing protocols for their cryopreservation. Commonly used cryoprotectants methanol, dimethyl sulfoxide (DMSO), propylene glycol (PG) and ethylene glycol (EG) were studied. Experiments were conducted with stage I and II zebrafish ovarian follicles, which were incubated in 50% L-15 medium containing different concentrations of cryoprotectants (0.25-5M) for 30 min at room temperature. Stage III zebrafish ovarian follicles were also used as comparisons. Two different tests were used to assess ovarian follicle viability: trypan blue (TB) and Fluorescein diacetate (FDA) + propidium iodide (PI) staining. Both TB and FDA+PI tests indicated that cryoprotectant toxicity to ovarian follicles increased in the order of methanol, DMSO, PG and EG. FDA+PI test was shown to be more sensitive than TB staining. No Observed Effect Concentrations (NOECs) for stage I and II follicles were 2M, 1M, 0.5M, and 0.25M for methanol, dimethyl sulfoxide (DMSO), propylene glycol (PG) and ethylene glycol (EG) respectively when assessed with FDA+PI. Stage III ovarian follicles appeared to be more sensitive than stage I and II ovarian follicles.

Mode of Action: Oxalate Crystal-Induced Renal Tubule Degeneration and Glycolic Acid-Induced Dysmorphogenesis—Renal and Developmental Effects of Ethylene Glycol

Ethylene glycol can cause both renal and developmental toxicity, with metabolism playing a key role in the mode of action (MOA) for each form of toxicity. Renal toxicity is ascribed to the terminal metabolite oxalic acid, which precipitates in the kidney in the form of calcium oxalate crystals and is believed to cause physical damage to the renal tubules. The human relevance of the renal toxicity of ethylene glycol is indicated by the similarity between animals and humans of metabolic pathways, the observation of renal oxalate crystals in toxicity studies in experimental animals and human poisonings, and cases of human kidney and bladder stones related to dietary oxalates and oxalate precursors. High-dose gavage exposures to ethylene glycol also cause axial skeletal defects in rodents (but not rabbits), with the intermediary metabolite, glycolic acid, identified as the causative agent. However, the mechanism by which glycolic acid perturbs development has not been investigated sufficiently to develop a plausible hypothesis of mode of action, nor have any cases of ethylene glycol-induced developmental effects been reported in humans. Given this, and the variations in sensitivity between animal species in response, the relevance to humans of ethylene glycol-induced developmental toxicity in animals is unknown at this time.

Ethylene glycol toxicosis in adult beef cattle fed contaminated feeds

Acute deaths of cows held in a drylot and fed several crop processing plant by-products were investigated. Clinical signs in affected cows included diarrhea, ataxia, recumbency, hypersalivation, and sunken eyes. A histological diagnosis of ethylene glycol toxicosis, based on numerous birefringent crystals in renal tubules, was supported by toxicologic findings.

Hyperoxaluria is reduced and nephrocalcinosis prevented with an oxalate-degrading enzyme in mice with hyperoxaluria

BACKGROUND/AIMS

Hyperoxaluria is a major risk factor for recurrent urolithiasis and nephrocalcinosis. We tested an oral therapy with a crystalline, cross-linked formulation of oxalate-decarboxylase (OxDc-CLEC) on the reduction of urinary oxalate and decrease in the severity of kidney injury in two models: AGT1 knockout mice (AGT1KO) in which hyperoxaluria is the result of an Agxt gene deficiency, and in AGT1KO mice challenged with ethylene glycol (EG).

METHODS

Four different doses of OxDc-CLEC mixed with the food, or placebo were given to AGT1KO mice (200 mg/day, n = 7) for 16 days and to EG-AGT1KO mice (5, 25, and 80 mg, n = 11) for 32 days.

RESULTS

Oral therapy with 200 mg OxDc-CLEC reduced both urinary (44%) and fecal oxalate (72%) in AGT1KO mice when compared to controls. Similarly, in EG-AGT1KO mice, each of the three doses of OxDc-CLEC produced a 30-50% reduction in hyperoxaluria. A sustained urinary oxalate reduction of 40% or more in the 80 mg group led to 100% animal survival and complete prevention of nephrocalcinosis and urolithiasis.

CONCLUSION

These data suggest that oral therapy with OxDc-CLEC may reduce hyperoxaluria, prevent calcium oxalate nephrocalcinosis and urolithiasis, and can represent a realistic option for the treatment of human hyperoxaluria, independent of cause.

Inhalation and epidermal exposure of volunteers to ethylene glycol: kinetics of absorption, urinary excretion, and metabolism to glycolate and oxalate

Ethylene glycol (EG) is a widely used liquid. Limited data are published regarding inhaled EG and no data regarding transdermal EG uptake in humans. In order to gain information on the quantitative fate of EG, four male volunteers inhaled between 1340 and 1610 micromol vaporous 13C-labeled EG (13C2-EG) for 4h. Separately, three of these subjects were epidermally exposed for up to 6h to liquid 13C2-EG (skin area 66 cm2). Plasma concentrations and urinary amounts of 13C2-EG were determined by gas chromatography with mass selective detection. Additionally, plasma was assayed for 13C-labeled glycolic acid 13C2-GA) and urine for 13C2-GA and 13C-labeled oxalic acid (13C2-OA). Both EG metabolites were nephrotoxic in animals and humans and embryotoxic in rodents. 13C-labels enabled to differentiate from also determined endogenous EG, glycolic acid (GA), and oxalic acid (OA). Of 13C2-EG inhaled, 5.5+/-3.0%, 0.77+/-0.15%, and 0.10+/-0.12% were detected in urine as 13C2-EG, 13C2-GA, and 13C2-OA, respectively. The skin permeability constant of liquid EG was 2.7 x 10(-5)+/-0.5 x 10(-5)cm/h. Of the dose taken up transdermally, 8.1+/-3.2% and up to 0.4% were excreted in urine as 13C2-EG and 13C2-GA, respectively. It is calculated that equally long-lasting exposure to 10 ppm vaporous EG or wetting of both hands by liquid EG leads to about the same body burden by EG and metabolites. The amounts of GA and OA excreted daily in urine as a result of exposure (8h/day) to 10 ppm EG are about 15% and 2%, respectively, of those excreted from naturally occurring endogenous GA and OA.

Effects of prevalent freshwater chemical contaminants on in vitro growth of Escherichia coli and Klebsiella pneumoniae

Many surface and ground waters in the continental US are contaminated with a variety of chemical pollutants, which are usually present in concentrations in the ppm and ppb range. The effects of these pollutants on coliform bacteria, which are prominent members of the aquatic flora, are poorly understood. Using a microtiter plate assay, isolates of Escherichia coli (from chicken intestine and fresh water), and an isolate of Klebsiella pneumoniae (from bovine milk) were exposed to varying concentrations of common pollutants over a 24 h period. The herbicides/pesticides simazine, atrazine, and diazinon; the VOCs trichloroethene and MTBE; the estrogens estradiol and estrone; and caffeine, all failed to inhibit bacterial growth at ppm levels. Only ethylene glycol, and the herbicide 2,4-D, significantly inhibited bacterial growth compared to controls. These results suggest that the replication of coliform bacteria in fresh waters is not adversely impacted by many common pollutants.

Mitochondrial dysfunction in an animal model of hyperoxaluria: a prophylactic approach with fucoidan

Oxalate/calcium oxalate toxicity is mediated through generation of reactive oxygen species in a process that partly depends upon events that induce mitochondrial damage. Mitochondrial dysfunction is an important event favoring stone formation. The objective of the present study was to investigate whether mitochondria is a target for oxalate/calcium oxalate and the plausible role of naturally occurring glycosaminoglycans from edible seaweed, fucoidan in ameliorating mitochondrial damage. Male albino rats of Wistar strain were divided into four groups and treated as follows: Group I: vehicle treated control, Group II: hyperoxaluria was induced with 0.75% ethylene glycol in drinking water for 28 days, Group III: fucoidan from F. vesiculosus (5 mg/kg b.wt, s.c) from the 8th day of the experimental period, Group IV: ethylene glycol+fucoidan treated rats. The tricarboxylic acid (TCA) cycle enzymes like succinate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and respiratory complex enzyme activities were assessed to evaluate mitochondrial function. Oxidative stress was assessed based on the activities of antioxidant enzymes, level of reactive oxygen species, lipid peroxidation and reduced glutathione. Mitochondrial swelling was also analyzed. Ultra structural changes in renal tissue were analyzed with electron microscope. Hyperoxaluria induced a decrease in the activities of TCA cycle enzymes and respiratory complex enzymes. The oxidative stress was evident by the decrease in antioxidant enzymes, glutathione and an increase in reactive species and lipid peroxidation in mitochondria. Mitochondrial damage was evident by increased mitochondrial swelling. Administration of fucoidan, decreased reactive oxygen species, lipid peroxidation (P<0.05), mitochondrial swelling and increased the activities of antioxidant enzymes and glutathione levels (P<0.05) and normalized the activities of mitochondrial TCA cycle and respiratory complex enzymes (P<0.05). From the present study, it can be concluded that mitochondrial damage is an essential event in hyperoxaluria, and fucoidan was able to effectively prevent it and thereby the renal damage in hyperoxaluria.

Effect of sulphated polysaccharides on erythrocyte changes due to oxidative and nitrosative stress in experimental hyperoxaluria

Kidney stones are known to haunt humanity for centuries and increase in oxalate is a predominant risk factor for stone formation. The present study was initiated with a notion to study the oxidative and nitrosative stress on erythrocytes under oxalate stress and the putative role of sulphated polysaccharides. Hyperoxaluria was induced in two groups by the administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with sulphated polysaccharides from Fucus vesiculosus from the 8th day to the end of the experimental period of 28 days at a dose of 5 mg/kg body weight subcutaneously. Control and drug control (sulphated polysaccharides alone) were also included in the study. Glycolic and glyoxylic acid levels of urine were analyzed as an index of hyperoxaluria. The plasma enzymic markers of cellular integrity, redox status of red blood cells, osmotic fragility, and (14)C-oxalate binding were investigated. Urine and plasma nitric oxide metabolites, expression of inducible nitric oxide synthase protein, and mRNA were assessed in kidney to evaluate the nitrosative stress. Increased levels of glycolic and glyoxylic acid in urine indicated the prevalence of hyperoxaluria in ethylene glycol-administered groups. Plasma aspartate and alanine transaminase were not altered, but alkaline phosphatase and lactate dehydrogenase of hyperoxaluric group were increased indicating tissue damage. Activities of antioxidant enzymes were decreased, whereas erythrocyte membrane lipid peroxidation was increased in hyperoxaluric rats. Moreover, an altered fragility with an increase in oxalate binding activity was observed in hyperoxaluric group. Increase in nitric oxide metabolites levels in urine and plasma along with an increase in expression of inducible nitric oxide synthase protein and mRNA in kidney were observed in hyperoxaluric rats. Administration of sulphated polysaccharides to hyperoxaluric rats averted the abnormal increase in urinary glycolic and glyoxylic acid levels and enzyme activities, decreased lipid peroxidation, and increased the activities of antioxidant enzymes. Furthermore, increased nitrosative stress accompanying hyperoxaluria was also normalized on sulphated polysaccharides treatment. To conclude, sulphated polysaccharide administration was able to maintain the integrity of erythrocyte membrane and decrease the damage to erythrocytes in hyperoxaluria.

Development of a cryopreservation protocol for long-term storage of black tiger shrimp (Penaeus monodon) spermatophores

The objectives of this study were to determine the effect of cryoprotectants on sperm viability and develop a freezing protocol for long-term storage of P. monodon spermatophores. Spermatophores suspended for 30 min in calcium-free saline (Ca-F saline) containing the cryoprotectants dimethyl sulfoxide (DMSO), ethylene glycol (EG), 1,2-propylene glycol (PG), formamide, and methanol at concentrations of 5, 10, 15, or 20% were studied using a modified eosin-nigrosin staining technique. The smallest reductions in apparent sperm viability occurred with DMSO; therefore, a freezing protocol was developed using Ca-F saline containing 5% DMSO. Spermatophores were cryopreserved using three protocols; cooling to a final temperature of -30, -80 or -80 degrees C and immediately stored in liquid nitrogen (cooling rates of -2, -4, -6, -8, -10, -12, -14 or -16 degrees C/min). Frozen spermatophores were thawed (2 min) at 30, 60, 70, or 90 degrees C. Successful cryopreservation of spermatophores in liquid nitrogen was achieved by a one-step cooling rate of -2 degrees C/min between 25 and -80 degrees C before storing in liquid nitrogen. Optimal thawing was in a 30 degrees C water bath for 2 min; this yielded live sperm after storage in liquid nitrogen for 210 days. Average sperm viability for fresh (97.8+/-2.9%) and cryopreserved spermatophores held for less than 60 days (87.3+/-4.1%) did not differ (P>0.05); however, that for spermatophores stored in liquid nitrogen between 90 and 210 days were lower (P<0.05) and varied from 27.3+/-3.4 to 53.3+/-4.3%. Thawed spermatophores previously held in liquid nitrogen for less than 62 days fertilized eggs (fertilization and hatching rates of 71.6-72.2% and 63.6-64.1%, respectively) at rates comparable to fresh spermatophores (70.8-78.2% and 66.3-67.8%, respectively). In conclusion, sperm within cryopreserved spermatophores stored in liquid nitrogen retained their viability for up to 210 days.

Effects of low-molecular-weight polyguluronate sulfate on experimental urolithiasis in rats

Urinary macromolecules, especially glycosaminoglycans (GAGs), have attracted great interest as promising inhibitors of urinary stone formation. As an analogue of GAGs, low-molecular-weight polyguluronate sulfate (LPGS) with strong polyanionic nature was prepared by chemical modification of brown algae extract. The effects of LPGS both on ethylene glycol-induced nephrolithiasis and Zinc disc implant-induced urinary bladder stone formation in Wistar rats were evaluated, and its acute toxicity in Kunming mice and Wistar rats were also investigated. The contents of renal oxalate and calcium in ethylene glycol-induced nephrolithiasic rats were decreased significantly from 5.01 +/- 0.96 to 3.26 +/- 1.31 mumol/g kidney (P < 0.01) and 20.11 +/- 4.60 to 11.83 +/- 3.54 mumol/g kidney (P < 0.01), respectively, after oral administration of LPGS at dose-level of 100 mg/kg. The renal crystal depositions and histopathological changes were reduced also. The formation of zinc disc implant-induced urinary bladder stones in rats was inhibited considerably after oral administration of LPGS at dose-levels of 50 mg/kg (P < 0.05) and 100 mg/kg (P < 0.01). The intravenous LD(50) and the oral maximum tolerance value of LPGS in mice are 6.29 and 25 g/kg, and in rats are 2.25 and 10 g/kg, respectively. These data show that LPGS has significant prevention effects both on nephrolithiasis and urinary bladder stone formation in rats, and negligible oral toxicity both in mice and rats. LPGS is a safe and promising drug candidate for the prevention of urolithiasis.

Calcium oxalate, and not other metabolites, is responsible for the renal toxicity of ethylene glycol

Ethylene glycol (EG) is nephrotoxic due to its metabolism. Many studies suggest that the toxicity is due to oxalate accumulation, but others have conversely suggested that toxicity results from effects of metabolites such as glycolaldehyde or glyoxylic acid on proximal tubule cells. In vivo studies have indicated that accumulation of calcium oxalate monohydrate (COM) corresponds closely with development of toxicity in renal tissue. The present studies were therefore designed to clarify the roles of various metabolites in the mechanism for EG toxicity in vitro by comparing the relative cytotoxicity of EG metabolites using three measures of cell death, ethidium homodimer uptake, lactate dehydrogenase (LDH) release and the conversion of the tetrazolium salt XTT to a colorimetric dye. Human proximal tubule cells in culture were incubated in physiologic buffers for 6h at 37 degrees C with COM (147-735microg/ml, an oxalate equivalence of 1-5mM), glycolate (5-25mM), glyoxylate (0.2-5mM) and glycolaldehyde (0.2-2mM). To assess the effects of acidity on the cytotoxicity, incubations were carried out at pH 6-7.4. The results show that COM dose-dependently increased LDH release and ethidium homodimer uptake, while the other metabolites did not. Conversely, COM had no effect on the XTT assay, while high concentrations of glycolaldehyde and glyoxylate decreased XTT activity, but the latter only at acidic pH. The correlation between the uptake of ethidium homodimer and the release of LDH suggest that COM is cytotoxic to human kidney cells in culture, while the XTT assay does not validly measure cytotoxicity in this system. These results indicate that COM, and not glyoxylate or glycolaldehyde, is the toxic metabolite responsible for the acute tubular necrosis and renal failure that is observed in EG-poisoned patients.

Neuropsychological sequelae of ethylene glycol intoxication: a case study

Ingestion of Ethylene glycol (EG) can result in a clinical syndrome marked by renal, cardiopulmonary, and neurological dysfunction. We present a case study addressing EG intoxication with neurological, radiological, and neuropsychological findings several days to weeks after initial ingestion and again at follow-up six months later. In our case study, CT scans of the head on days one and two post EG ingestion were essentially normal, as was a brain MRI six months later. An MRI of the brain on day five revealed nonspecific cerebellar white matter abnormalities. Neuropsychological assessment at three to four weeks post admission indicated global cognitive impairment with particular deficits in attention, processing speed, constructional ability, language, and memory retrieval. Results at six months follow-up indicated partial improvement in overall cognitive functioning with remaining deficits in processing speed, naming, and constructional ability. These findings suggest that EG intoxication is capable of causing lasting neuropsychological sequelae despite evidence of relatively normal neuroradiologic findings.

Effect of cryopreservation on viability, activation and growth of in situ and isolated ovine early-stage follicles

Isolated or cortical tissue-enclosed (in situ) sheep early-stage follicles were exposed to 1.5 M dimethyl sulfoxide (DMSO), ethylene glycol (EG) or unexposed, or frozen/thawed in the presence of these cryoprotectants and then cultured for 5 days in enriched minimal essential medium (MEM) or not cultured. Cultured and uncultured follicles were classified as non-viable/viable when they were stained/not stained with trypan blue, respectively. Follicular diameter was measured and the percentages of primordial and developing follicles calculated. Exposure of isolated or in situ follicles to DMSO or EG led to a marked decrease in the percentage of viable follicles. The percentage of viable isolated and in situ follicles further decreased when they were in vitro-cultured for 5 days, EG-exposed follicles generally showing a more damaging effect than DMSO-exposed follicles. Cultured follicles, both isolated and in situ, which were exposed to EG and DMSO, as well as in situ follicles, which had been frozen/thawed in the presence of one of these cryoprotectants, showed similar growth rates as cultured, untreated follicles, while in these groups significantly lower percentages of primordial follicles and higher percentages of more advanced follicular stages were observed. Among the treated groups, the highest percentage (71-75%) of developing follicles was observed after culturing cryoprotectant-exposed isolated follicles. In contrast, when cryopreserved, isolated follicles were cultured, they did not increase in diameter and did not develop into more advanced stages. In conclusion, exposure to or cryopreservation in the presence of EG and DMSO, as well as their further in vitro culture, negatively affected the viability of ovine isolated and in situ early-stage follicles. In vitro growth of early-stage follicles and activation of primordial follicles were better maintained when follicles had been frozen/thawed and cultured in situ.

Evaluation of hepatobiliary scintigraphy as an indicator of hepatic function in domestic pigeons (Columba livia) before and after exposure to ethylene glycol

This study investigated the use of quantitative hepatobiliary scintigraphy to assess liver function in 14 white Carneaux pigeons (Columba livia). Liver scintigraphy using 99mTc-mebrofenin was performed and liver function was quantified using deconvolutional analysis and the area under the normalized heart time-activity curve as previously described in the dog and horse. Liver biopsies were performed in all birds before and after toxin-induced liver damage with ethylene glycol. Before the induction of liver disease, all biopsy specimens showed varying degrees of granulomatous inflammation. After ethylene glycol administration, hepatic lesions were scored and compared with scintigraphic findings. Scintigraphic results showed a significant decrease (P = 0.04) in hepatic function using the area under the normalized time-activity curve. There was good correlation between the overall histologic score posttoxin exposure and scintigraphic measures of liver function (P < 0.03). Based upon these preliminary results, the area under the heart time-activity curve can determine hepatic extraction as a measure of hepatic parenchymal cell function. The results also showed that worsening hepatic cellular function correlated with increased histologic damage to the liver. The use of hepatobiliary scintigraphy using 99mTc-mebrofenin to determine liver function in pigeons has not been previously reported. Additional studies are warranted to evaluate the application of this technique in clinical patients and to establish the sensitivity of this technique.

Aluminum citrate inhibits cytotoxicity and aggregation of oxalate crystals

Calcium oxalate monohydrate (COM), which represents a major component of kidney stones, is an end metabolite of ethylene glycol. COM accumulation has been linked with acute renal toxicity in ethylene glycol poisoning. COM injures the kidney either by directly producing cytotoxicity to the kidney cells or by aggregating in the kidney lumen leading to the blockage of urine flow. The present studies were designed to examine whether aluminum citrate could reduce the toxicity of COM. Toxicity was determined in human proximal tubule cells by leakage of lactate dehydrogenase or uptake of ethidium homodimer and in erythrocytes by degree of hemolysis. Aluminum citrate significantly inhibited the leakage of lactate dehydrogenase from human proximal tubule cells and protected against cell death from COM. The inhibitory effect of aluminum citrate was greater than that of other citrate or aluminum salts such as sodium citrate, aluminum chloride, calcium citrate, ammonium citrate or potassium citrate. Aluminum citrate significantly inhibited the aggregation of COM crystals in vitro and decreased red cell membrane damage from COM. Aluminum citrate appeared to directly interact with COM, but not with the cell membrane. As such, aluminum citrate reduced the cytotoxicity by a physico-chemical interaction with the COM surface, and not by dissolving the COM crystals. These studies suggest that aluminum citrate may protect against tissue damage that occurs with high levels of oxalate accumulation, especially in ethylene glycol poisoning and possibly in hyperoxaluric states.

[Hormone replacement therapy: toxicity of glycol ethers]

Glycol ethers (GE) belong to two main series: series E, which include ethylene glycol ethers (EGE) and series P which include propylene glycol ethers (PGE). GE are widely used as solvents in a large number of industrial, household and cosmetic applications. EGE can be found in water paints, varnishes, inks, household products. Severe adverse effects have been noted with pharmaceutical formulations containing diethylene glycol monoethyl-ethers and this led to withdrawal from the French market. The toxicity of GE depends on the molecular weight and the metabolites generated. It can manifest following acute or chronic exposure by disorders of the nervous system, bone marrow, immune system, kidneys as well as fertility, reproduction and embryofetal development. Several EGE are mutagenic. The carcinogenic risk is not known. The most toxic derivatives EGME, EGMEA, EGEE and EGEEA alter male and female fertility, and induce malformations. Taking these toxic effects into consideration, what is the place of GE as absorption promoting agents? An example is DEGEE, which facilitates estradiol penetration when used as a gel in the treatment of estrogen deficiency. This review is intended to address this issue.

Cryopreservation of the late stage embryos of Spodoptera exigua (Lepidoptera: Noctuidae)

Genetic devolution, genetic drift and contamination are all threats to maintain germplasm stability during mass rearing of many insects. Cryopreservation of beet armworm (Spodoptera exigua) embryos was studied to provide information to improve mass rearing. A series of experiments was conducted on late-stage embryos (45-48 h at 27 degree C) of the beet armyworm, which included evaluation of cryoprotectants (CPAs), their toxicity and glass-forming tendency and optimization of experimental procedures. The results showed that ethylene glycol (EG) was the best CPA with comparatively low toxicity compared to the other six CPAs tested (methanol, 1,3-propanediol, glycerol, 2-amino-1-ethanol, 3-amino-1-propanol 3-methoxy-1 and 2-propanediol). The highest hatching rate of 8.8 degree was attained after freezing with a 3-step loading procedure and a 1-step unloading procedure, but the hatched larvae from frozen-thawed embryos did not actively feed and could not develop to a later stage. This was attributed to injuries from freezing in late stage embryos of S. exigua which had formed midguts.

Respirometry-based evaluation of the fate and possible effects of antifreeze on activated sludge

This paper focuses on environmental concerns regarding used antifreeze. It shows the results of laboratory respirometric tests conducted to evaluate the potential impact of antifreeze on activated sludge. In this first step of the study, only the components of virgin antifreeze were addressed, i.e. ethylene glycol, and antifoaming and corrosion inhibitory substances. The plateau resulting from oxygen uptake rate measurements of mixed liquor taken at the end of an aeration tank is used as a reference to evaluate the response of biomass to pulse injection of increasing dosages of new antifreeze, compared to that of formaldehyde, a known toxic compound. While 200 mg/L of formaldehyde steadily decreased the biomass activity (7 mg O2/Lh), there were no toxicity effects for doses up to 5000 mg/L of ethylene glycol from new antifreeze coolant (23 mg O2/Lh, compared to the initial 15 mg O2/Lh for the mixed liquor). It is estimated that ethylene glycol concentration in municipal wastewaters should be several order of magnitude lower then the 1000 mg/L shown to be tolerated by the biomass in this work, but at the present stage, the research does not provide enough information to recommend a definitive management scheme for antifreeze discharge. Many other management issues for used antifreeze must be addressed in future studies before any decision on tolerating sewer discharge in Mexico, as a transitory management option that will conciliate the actual practices with legality, can be made.

Japanese flounder (Paralichthys olivaceus) embryos are difficult to cryopreserve by vitrification

The first successful cryopreservation of fish embryos was reported in the Japanese flounder by vitrification [Chen and Tian, Theriogenology, 63, 1207-1219, 2005]. Since very high concentrations of cryoprotectants are needed for vitrification and fish embryos have a large volume, Japanese flounder embryos must have low sensitivity to cryoprotectant toxicity and high permeability to water and cryoprotectants. So, we investigated the sensitivity and the permeability of Japanese flounder embryos. In addition, we assessed the survival of flounder embryos after vitrification with solutions containing methanol and propylene glycol, following Chen and Tian's report. The embryos were relatively insensitive to the toxicity of individual cryoprotectants at lower concentrations, especially methanol and propylene glycol as their report. Although their permeability to water and cryoprotectants could not be measured from volume changes in cryoprotectant solutions, the embryos appeared to be permeable to methanol but less permeable to DMSO, ethylene glycol, and propylene glycol. Although vitrification solutions containing methanol and propylene glycol, which were used in Chen and Tian's report, were toxic to embryos, a small proportion of embryos did survived. However, when vitrified with the vitrification solutions, no embryos survived after warming. The embryos became opaque during cooling with liquid nitrogen, indicating the formation of intracellular ice during cooling. When embryos had been kept in vitrification solutions for 60 min after being treated with the vitrification solution, some remained transparent during cooling, but became opaque during warming. This suggests that dehydration and/or permeation by cryoprotectants were insufficient for vitrification of the embryos even after they had been over-treated with the vitrification solutions. Thus, Chen and Tian's cryopreservation method lacks general application to Japanese flounder embryos.

Effect of Moringa oleifera Lam. root-wood on ethylene glycol induced urolithiasis in rats

In India, drumstick (Moringa oleifera Lam. (Moringaceae)) is commonly used as a phytotherapeutic agent. The effect of oral administration of aqueous and alcoholic extract of Moringa oleifera root-wood on calcium oxalate urolithiasis has been studied in male Wistar albino rats. Ethylene glycol feeding resulted in hyperoxaluria as well as increased renal excretion of calcium and phosphate. Supplementation with aqueous and alcoholic extract of Moringa oleifera root-wood significantly reduced the elevated urinary oxalate, showing a regulatory action on endogenous oxalate synthesis. The increased deposition of stone forming constituents in the kidneys of calculogenic rats was also significantly lowered by curative and preventive treatment using aqueous and alcoholic extracts. The results indicate that the root-wood of Moringa oleifera is endowed with antiurolithiatic activity.