Dose Of Glycol Research Articles

Clinical manifestations and renal pathology of ethylene glycol.

Ethylene glycol (EG) poisoning is a critical medical emergency often associated with suicide attempts in adults. EG is metabolized by alcohol dehydrogenase, leading to the formation of toxic metabolites that cause metabolic acidosis, renal failure, hypocalcemia, aciduria, and disorders of the central nervous and cardiovascular systems. Calcium oxalate, a metabolite of EG, contributes to acute tubular necrosis. Despite limited reports on human renal pathology, we present a case detailing renal pathology following EG ingestion. A 44-year-old male, admitted due to loss of consciousness, had ingested a lethal dose of EG. Blood tests indicated metabolic acidosis, while urinary examination revealed calcium oxalate crystals. Continuous renal replacement therapy corrected the acidosis; however, nephrogenic diabetes insipidus subsequently developed. A renal biopsy on day 31 revealed calcium oxalate crystal deposition and tubulointerstitial damage. Notably, various stages of crystal deposition, adherence, and degradation were observed. This case underscores the importance of considering EG poisoning in cases of unexplained metabolic acidosis and renal dysfunction, with renal biopsy serving as a valuable diagnostic tool. Understanding the renal effects of EG is essential for timely intervention and effective management of poisoning cases.

<b>Acute toxicity effects of ethylene glycol on lethal dose 50 (LD50), urine production, and histopathology change renal tubule cell in mice</b>

Background: The LD50 (lethal dose causing 50% mortality) of ethylene glycol (EG) and its associated toxicity in mice (Mus musculus) were assessed by evaluating kidney function. Aim: This study aimed to determine the acute toxicity of oral lethal dose 50% (LD50) of ethylene glycol, also degeneration, necrosis, and inflammatory cell invasion in kidney tubules of male rats (Rattus norvegicus) as animal model. Methods: There were 66 DDG (Deutschland Denken Yoken) mice in 11 groups of six in this investigation. The daylong metabolic cage study contained one control (C) and ten treatment groups that received different EG doses. EG's daily BW/kg dosage varied from 0.5 mg/kg to 15,000 mg/kg. The treatment group was given a single dose of EG at a dose of T1 = 0.5 mg/kg BW, T2 = 1.57 mg/kg BW, T3 = 4.94 mg/kg BW, T4 = 15.54 mg/kg BW, T5 = 48.84 mg/kg BW, T6 = 153.55 mg/kg BW, T7 = 482.74 mg/kg BW, and T8 = 1517.66 mg/kg BW T9 = 4771.24 mg/kg BW, T10 = 14999.99 ≈ 15. 000 mg/kg BW. One-way ANOVA testing was used to analyze the data. Results: The LD50 value of EG in mice was determined to be 1.598 mg/kg BW, classifying EG as "Slightly Toxic." According to renal histopathology, EG dosage increased renal tubular degeneration, necrosis, and interstitial inflammatory cell infiltration. Acute renal impairment and lower urine output were observed in the EG (4.94 mg/kg - 1517.66 mg/kg BW). Histologically, EG levels are associated with renal tubular cell degeneration, necrosis, and interstitial inflammatory cell growth. Conclusion: Acute EG exposure caused renal failure in male mice. Acute exposure to EG causes renal tubular cell degeneration and inflammation, indicating toxicity and health hazards.

Protective effect of bee pollen in acute kidney injury, proteinuria, and crystalluria induced by ethylene glycol ingestion in rats

Oxidative stress plays a role in hyperoxaluria-induced kidney injury and crystallization. Bee pollen is a hive product with a high content of antioxidants. The antioxidant content and protective effect of bee pollen extract (BPE) against ethylene glycol (EG) induced crystalluria, and acute kidney injury (AKI) were investigated. The effect of BPE on the EG-induced liver injury and proteinuria was also examined. Ten groups of male Wister rats were treated daily with vehicle, cystone, BPE (100, 250, and 500 mg/kg b.wt.), and group 6–9 treated with EG, EG + BPE (100, 250, and 500 mg/kg b.wt.) and group 10 EG + cystone. The dose of EG was 0.75% v/v, and the dose of cystone was 500 mg/kg b.wt. On day 30, blood and urine samples were collected for analysis. Kidneys were removed for histopathological study. The antioxidant activity of BPE was assessed, and its total phenols and flavonoids were determined. EG significantly increased urine parameters (pH, volume, calcium, phosphorus, uric acid, and protein), blood urea, creatinine, and liver enzymes (P < 0.05). EG decreased creatinine clearance and urine magnesium and caused crystalluria. Treatment with BPE or cystone mitigates EG's effect; BPE was more potent than cystone (P < 0.05). BPE increases urine volume, sodium, and magnesium compared to the control and EG treated groups. BPE reduces proteinuria and prevents AKI, crystalluria, liver injury, and histopathological changes in the kidney tissue caused by EG. BPE might have a protective effect against EG-induced AKI, crystalluria, proteinuria, and stone deposition, most likely by its antioxidant content and activity.

Effect of Ethylene Glycol on Structural Integrity at Each Stage of Preantral Follicle Development Post Vitrification of Rat Ovary-Histological Analysis

The structure of follicular tissue affects the ability to maintain the structural integrity of follicles against cryoinjury post-vitrification. Histological analysis was conducted on the structural integrity of each stage of preantral follicles post-vitrification using 7.5% and 15.0% doses of ethylene glycol (EG), and ovarian sections with HE staining were observed using an Olympus CX21 microscope connected to Optilab 3.0 lens and Image Raster software. Analysis was conducted on the ovarian cortex in the tracing line area using polygon measure tools to obtain follicle density (follicles/mm2) and follicle index (%) data. The result showed that the EG group 7.5% (KP1) increased follicle density compared to the vitrified group (KKV) in primordial (15.83±1.77) and primary (22.94±8.51) stages. Meanwhile, KP2 (EG 15%) was in primordial (41.92±6.45), primary (11.69±1.95), secondary (33.48±3.63), and tertiary (5.93±0.69) stages. KP1 increased grade 3 follicle index compared to KKV in primary (27.66±2.34), secondary (32.41±6.99), and tertiary (25.00±5.00) stages. Meanwhile, KP2 was in primary (26.87±6.68) and tertiary (25.00±5.00) stages. Both doses of 7.5% and 15.0% EG were able to maintain structural integrity at certain stages of preantral follicles. Secondary and tertiary follicles are the best stages in maintaining grade 3 follicular integrity with the addition of 7.5% EG.

Acute pulmonary toxicity and inflammation induced by combined exposure to didecyldimethylammonium chloride and ethylene glycol in rats

Didecyldimethylammonium chloride (DDAC), an antimicrobial agent, has been reported to induce pulmonary toxicity in animal studies. DDAC is frequently used in spray-form household products in combination with ethylene glycol (EG). The purpose of this study was to evaluate the toxic interaction between DDAC and EG in the lung. DDAC at a sub-toxic dose (100 μg/kg body weight) was mixed with a non-toxic dose of EG (100 or 200 μg/kg body weight), and was administrated to rats via intratracheal instillation. Lactate dehydrogenase activity and total protein content in the bronchoalveolar lavage fluid (BALF) were not changed by singly treated DDAC or EG, but significantly enhanced at 1 d after treatment with the mixture, with the effect dependent on the dose of EG. Total cell count in BALF was largely increased and polymorphonuclear leukocytes were predominantly recruited to the lung in rats administrated with the mixture. Inflammatory cytokines, tumor necrosis factor-alpha and interleukin-6 also appeared to be increased by the mixture of DDAC and EG (200 μg/kg body weight) at 1 d post-exposure, which might be associated with the increase in inflammatory cells in lung. BALF protein content and inflammatory cell recruitment in the lung still remained elevated at 7 d after the administration of DDAC with the higher dose of EG. These results suggest that the combination of DDAC and EG can synergistically induce pulmonary cytotoxicity and inflammation, and EG appears to amplify the harmful effects of DDAC on the lung. Therefore pulmonary exposure to these two chemicals commonly found in commercial products can be a potential hazard to human health.

English

Origanum vulgaris (Oregano) has been used in the fluky medicinal for treating various diseases including urolithiasis and hypertension. This study was designed to investigate the possible antioxidant and antiurolithic activities of different standardized extracts of Oregano ethanol extract n-hexane, ethyl acetate, and aqueous fraction on rats. The dried hydroalcoholic extract of 70% ethyl alcohol Oregano was suspended in water and successively extracted with n-hexane and ethyl acetate. Each active extract was screened of phytochemical and standardized spectrophotometricaly by estimation of total phenol and total flavonoid content. Antiurolithic and antioxidant activities were studied on live rat model by oral doses of ethylene glycol and NH4Cl. The active extracts of Oregano (20 mg/kg) were given to different groups and one group without extracts was used as control. At the end of the experimental period, blood samples were obtained from studying biochemical parameters and a kidney specimen for histopathology using scanning electron microscope. Ethanol extract, n-hexane and aqueous fractions prevented as well as opposed toxic changes, including loss of body weight gain and appetite, raised serum urea, uric acid and creatinine levels, and crystal deposition in the kidneys. These potential urolithitic effects of ethylene glycol should be taken into considerations with close monitoring of kidney function tests at frequent intervals. The oregano antioxidant effect might be more effective in the amelioration of ethylene glycol induced kidney injury and urolithiasis. Key words: Anihypertensive, Origanum vulgaris, urolithiasis, renoprotective, rats.

The Impact of Dose Rate on Ethylene Glycol Developmental Toxicity and Pharmacokinetics in Pregnant CD Rats

High-dose bolus exposure of rats to ethylene glycol (EG) causes developmental toxicity mediated by a metabolite, glycolic acid (GA), whose levels increase disproportionately when its metabolism is saturated. However, low-level exposures that do not saturate GA metabolism have a low potential for developmental effects. Toward the goal of developing EG risk assessments based on internal dose metrics, this study examined the differences between fast (bolus) and slow (continuous infusion) dose-rate exposures to EG on developmental outcome and pharmacokinetics. Time-mated female CD rats received sc bolus injections of 0, 1000, or 2000 mg/kg/day of EG on gestation day (GD) 6-15 once daily, whereas three corresponding groups were given the same daily doses as an infusion administered continuously from GD 6-15 via an sc implantable pump. In the sc bolus groups, increases in 11 fetal malformations (major defects) and 12 variations (minor alterations) were seen at the 2000 mg/kg/day dose level, whereas increases in 2 malformations and 2 variations occurred at 1000 mg/kg/day. In contrast, equivalent daily doses of EG given slowly via infusion did not cause any developmental effects. A pharmacokinetics time course was then conducted to compare GD 11-12 kinetics from oral bolus (gavage) exposure versus sc infusion of EG. Although dose rate had a modest impact (8- to 11-fold difference) on peak EG levels, peak levels of GA in maternal blood, kidney, embryo, and exocoelomic fluid were 59, 100, 49, and 56 times higher, respectively, following gavage versus the same dose given by infusion. These data illustrate how high-dose bolus exposure to EG causes a dramatic shift to nonlinear GA kinetics, an event which is highly unlikely to occur following exposures to humans associated with consumer and worker uses.

Dermal Penetration of Ethylene Glycol Through Human Skin In Vitro

This study was conducted to determine the in vitro dermal absorption of ethylene glycol (EG) through dermatomed human abdominal skin (containing epidermis and dermis), obtained from cadavers within 24 hours of death and kept frozen until processed. Three formulations of EG (neat, 50%, and 10% aqueous solutions) were applied in triplicate to skin samples from 6 donors, and placed in Teflon Bronaugh flow-through diffusion cells. Barrier integrity of each sample was evaluated with (3)H-H(2)O prior to applying EG and only data from samples passing the test were used. A physiological receptor fluid was pumped beneath the skin samples and collected in a fraction collector at predetermined time points through 24 hours. Possible volatilized EG was trapped in a charcoal basket located above each skin sample. Each skin sample was treated with an infinite dose of 500 microL of EG formulation/cm(2). At the end of 24 hours, volatilized EG trapped in the headspace was collected, the unabsorbed dose was removed from the skin and the skin was rinsed, tape stripped, and solubilized along with a rinse of the flow-through cells, and total radioactivity was determined. Only a small fraction (</=1%) of the applied EG was absorbed in 24 hours, of which <0.7% penetrated through the skin and ~0.4% remained in the skin. Recovery (mass balance) of the applied EG was between 93% and 99%, which further validated the observed low dermal penetration of EG. The net penetration of the applied EG over 24 hours was concentration proportional, comprising 2.97 +/- 0.78, 1.75 +/- 0.62, and 0.23 +/- 0.12 mg/cm(2) of the neat, 50%, and 10% formulations, respectively. The steady-state flux of EG was established between 16 and 24 hours. The mean steady-state flux of EG through dermatomed skin was 217, 129, and 15 microg/cm(2)h for the neat, 50%, and 10% aqueous formulations, respectively, consistent with concentration-proportional penetration of EG. The steady-state permeation coefficient (Kp) for EG was low, between 1.5 x 10(-4) and 2.6 x 10(-4) cm/h. These findings demonstrate that EG dermal penetration is expected to be very low and to be slow, indicating very limited systemic or internal dose of EG due to dermal exposure.

Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats

To determine the safety and efficacy of high-dose fomepizole compared with ethanol (EtOH) in cats with ethylene glycol (EG) toxicosis. Prospective study. University veterinary research laboratory. Thirteen cats. Two cats received injections of high-dose fomepizole (Study 1). Three cats received lethal doses of EG and fomepizole treatment was initiated 1, 2, or 3 hours later (Study 2). Eight cats received a lethal dose of EG and were treated with fomepizole or EtOH (Study 3). Cats treated with fomepizole received 125 mg/kg IV initially, then 31.25 mg/kg at 12, 24, and 36 hours. Cats treated with EtOH received 5 mL of 20% EtOH/kg IV initially, then every 6 hours for 5 treatments, then every 8 hours for 4 treatments. Cats also received fluids and supportive therapy as needed. Clinical signs were monitored and serial blood analyses performed. Cats receiving fomepizole experienced mild sedation but no biochemical evidence of toxicity. Cats receiving fomepizole for EG intoxication survived if therapy was initiated within 3 hours of EG ingestion. One of the 6 developed acute renal failure (ARF) but survived. Only 1 of the 3 cats treated with EtOH 3 hours following EG ingestion survived; 2 developed ARF and were euthanized. Cats treated 4 hours following EG ingestion developed ARF, whether treated with EtOH or fomepizole. Fomepizole is safe when administered to cats in high doses, prevents EG-induced fatal ARF when therapy is instituted within 3 hours of EG ingestion, and is more effective than treatment with EtOH.

In vivo efficacy of Trachyspermum ammi anticalcifying protein in urolithiatic rat model

Ethnopharmacological relevance Many medicinal plants have been employed during ages to treat urinary stones though the rationale behind their use is not well established. Recently, we have successfully purified an anticalcifying protein from the seeds of Trachyspermum ammi (L.) Sprague ex Turril (Umbelliferae) using oxalate depletion assay and deciphered its inhibitory activity against calcium oxalate crystal growth. Aim In this report, the antilithiatic activity of Trachyspermum ammi anticalcifying protein (TAP) was studied in urolithiatic rat model. Methodology Urolithiasis was induced by exposure of 0.4% ethylene glycol (EG) and 1.0% ammonium chloride (NH 4Cl) for 9 days. The efficacy of TAP was studied in another group given same dose of EG and NH 4Cl in addition to 2 mg/kg body weight of TAP. Further, we evaluated ability of TAP to inhibit the attachment of calcium oxalate (CaO x ) crystal in kidney tissue and studied the consequences of CaO x adhesion on renal functioning and tissue integrity. Results The antilithiatic potential of TAP was confirmed by its ability to maintain renal functioning, reduce renal injury and decrease crystal excretion in urine and retention in renal tissues. Conclusions Thus, the present investigation suggests the potential of TAP in preventing calcium oxalate deposition and forms the basis for the development of antilithiatic drug interventions against urolithiasis.

Endogenous oxalogenesis after acute intravenous loading with ethylene glycol or glycine in rats receiving standard and vitamin B6‐deficient diets

The effect on endogenous oxalate synthesis of acute intravenous loading with ethylene glycol or glycine was investigated in rats on a standard or a vitamin B6-deficient diet. Twenty-four male Wistar rats weighing approximately 180 g were randomly divided into ethylene glycol and glycine groups of 12 animals each. These groups were further divided into two subgroups of six animals each that were fed either a standard or a vitamin B6-deficient diet for 3 weeks. Animals of these two subgroups received an intravenous infusion of 20 mg (322.22 micromol) of ethylene glycol or 100 mg (1332.09 micromol) of glycine, respectively. Urine samples were collected just before intravenous infusion of each substance and at hourly intervals until 5 h after receiving the infusion. Urinary oxalate, glycolate, and citrate levels were measured by capillary electrophoresis. Urinary oxalate and glycolate excretion was significantly increased after ethylene glycol administration. Significant differences between the control and vitamin B6-deficient groups were found. In contrast, there were only small changes of oxalate and glycolate excretion after glycine administration. Recovery of the given dose of ethylene glycol as oxalate in 5-h urine was 0.31% and 7.15% in the control and vitamin B6-deficient groups, respectively, whereas recovery of glycolate was 0.68% and 7.22%, respectively. Ethylene glycol loading has a significant effect on urinary oxalate excretion in both normal and vitamin B6-deficient rats, whereas glycine loading only has a small effect. Oxalate and glycolate excretion after ethylene glycol loading were respectively 23-fold and 11-fold higher in vitamin B6-deficient rats than in controls.

Effects of subacute treatment of ethylene glycol on serum marker enzymes and erythrocyte and tissue antioxidant defense systems and lipid peroxidation in rats

The present study was aimed to investigate the effects of ethylene glycol (EG) on serum marker enzymes, antioxidant defense systems and lipid peroxidation concentration (malondialdehyde = MDA) in various tissues of rats exposed to ethylene glycol. EG (1.25% or 2.5%) in drinking water was administered orally to rats (Sprague–Dawley albino) ad libitum for 21 days continuously. EG treatments caused different effects on the serum marker enzymes, antioxidant defense system and MDA content in various tissues of the treatment groups as compared with the controls. EG also caused a significant increase in the serum marker enzyme activities with 2.5% dosage whereas, no changes were not observed with 1.25% dosage of EG treatment. Lipid peroxidation significantly increased in all the tissues except for in the heart and stomach of rats treated with both dosages of EG. Also, the antioxidative systems were also seriously affected by EG. For example, SOD significantly decreased in the liver treated with both dosages whereas, SOD activity in the erythrocytes, kidney, heart and stomach were significantly increased and not changed in the brain with two dosages of EG. Also, while CAT activity significantly decreased in the erythrocytes, liver and kidney, the activity in the stomach significantly increased, but did not change in the brain and heart with two doses of EG. GR activity significantly decreased in the erythrocytes treated with both dosages of EG whereas GR was not affected in other tissues by EG treatment. GST activity significantly elevated in the heart and brain but did not change in the other tissues of rats treated with both dosages of EG. Meanwhile, GSH depletion in the erythrocytes of rats treated with 2.5% dosage of EG was found to be significant whereas, the level of GSH in the brain was significantly increased treated with both the dosages of EG. The observations presented led us to conclude that the administration of subacute EG promotes lipid peroxidatin content, elevates tissue damage serum marker enzymes and changes in the antioxidative systems in rats. These data, along with the determined changes suggest that EG produced substantial systemic organ toxicity in the erythrocyte, liver, brain, heart kidney and stomach during the period of a 21-day subacute exposure.

소 체외수정란의 Slow Freezing을 위해서 Ethylene Glycol 동결보호제에 Sucrose 첨가 농도에 의한 동결효율

The present study was undertaken to investigate the post-thawed survivability of bovine embryo depending on different dose of ethylene glycol and sucrose. Ovaries were collected at local slaughterhouse and the cumulus-oocyte-complexes aspirated from ovaries were in vitro matured, fertilized and cultured at 39°C in an atmosphere of 5% CO2 incubator. For conventional slow-freezing, d 7 or 8 expanded blastocysts were collected. Embryos were equilibrated in 1.5 M and 1.8 M ethylene glycol(EG) with 0.1 M and 0.3 M sucrose in Dulbecco's phosphate-buffered saline(D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25 ml-straw and placed directly into cooling chamber of programmable freezer precooled to ��7°C, after 2 min, the straw was seeded, maintained at ��7°C for 8 min, and then cooled to ��35°C at 0.3°C/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 sec and exposed to 37°C water for 20 sec. Straws were then removed from 37°C water. Rates of blastocyst survive and hatching were evaluated at 24 to 72 h post-warming. No difference of the survivability was shown between 1.5 M and 1.8 M EG (71 and 70%, respectively). Addition of 0.1 M sucrose to 1.5 M and 1.8 M ethylene glycol in the freezing solution did not differ significantly embryo survival (74 and 77%, respectively), whereas survival rates was higher(89%) in freezing solution contained 0.3M sucrose to 1.8M EG compared with 0.3M sucrose to 1.5 M EG group(71%). However, there was no difference in the overall total cell number between the two groups (122 ± 1.8 vs 131 ± 1.4, respectively). In conclusion, the results suggest that 0.3 M sucrose in 1.8 M EG may be optimal condition for freezing and thawing methods with in vitro produced embryos and may be applied to on-farm conditions for embryo transfer.

Successful transplantation of a liver from a donor with fatal ethylene glycol poisoning

Successful transplantation of a liver from a donor with fatal ethylene glycol poisoning

Ethylene glycol[ndash ]mediated tubular injury: Identification of critical metabolites and injury pathways

Ethylene glycol (EG) intoxication produces multisystem organ injury, including acute renal failure. Although EG must be metabolized to toxic intermediates to induce organ damage, the specific metabolite(s) responsible and the underlying pathogenic mechanisms remain poorly defined. To explore these issues, isolated mouse proximal tubular segments (PTSs) were incubated with either varying doses of EG or its prime metabolites (glycolate, glycoaldehyde, glyoxylate, or oxalate for 15 to 60 minutes). Injury was assessed by the percentage of lactate dehydrogenase (LDH) release, LDH destruction, adenosine triphosphate (ATP) depletion, or membrane phospholipid degradation. Toxicities were also assessed in cultured HK-2 cells over 18 hours (by MTT assay). EG, glycolate, and oxalate did not induce overt PTS injury. Conversely, glyoxylate and glycoaldehyde were highly toxic, causing profound ATP depletion and LDH release. Glycoaldehyde also caused enzyme (LDH) and selected phospholipid degradation (phosphatidylethanolamine, phosphatidylserine). These changes were not seen with glyoxylate treatment. Acidosis (pH 6.8) and glycine (2 mmol/L) each blocked glyoxylate, but not glycoaldehyde toxicity, indicating differing injury pathways. Only glycoaldehyde and glyoxylate induced marked HK-2 cell death. We conclude that glycoaldehyde and glyoxylate are the principal metabolites responsible for EG nephrotoxicity and do so by causing ATP depletion and phospholipid and enzyme destruction. Glycine and acidosis, by-products of EG metabolism, can attenuate glyoxylate-mediated injury. This suggests that naturally occurring but incomplete protective pathways may be operative during the evolution of EG cytotoxicity. [copy ] 2001 by the National Kidney Foundation, Inc.

Role of macrophages in nephrolithiasis in rats: An analysis of the renal interstitium

Interstitial calcium oxalate (CaOx) crystals can be found in primary oxalosis and in secondary hyperoxaluria. In a rat model for nephrolithiasis, we investigated whether such crystals can be removed by the surrounding interstitial cells. CaOx crystals were induced by a crystal-inducing diet based on ethylene glycol (EG) and ammonium chloride (CID). Both lithogenic compounds were added to the drinking water. After 9 days, the animals received normal drinking water for 2 days. Using this CID, only the interstitial crystals are retained. Subsequently, half of the population remained on normal drinking water (normo-oxaluria), whereas the other half received a low dose of EG alone (chronic hyperoxaluria). The rats were killed at regular times thereafter. The results showed that the kidney-associated oxalate significantly declined during normo-oxaluria, but remained high during chronic hyperoxaluria. Interstitial cells positive for the leukocyte common antigen (CD45; which identifies all types of leukocytes), the ED1 antigen (which is specific for monocytes and macrophages), and the major histocompatibility class II antigen (MCHII), respectively, had increased in number, with minor differences between both rat populations. The cells around the interstitial crystals were mostly positive for ED1. Multinucleate giant cells were regularly observed. These cells were positive for CD45 and ED1 and sometimes also for MCHII. The crystals in these cells were moderately positive for acid phosphatase and carbonic anhydrase II. It is concluded that interstitial CaOx crystals can be removed under normo-oxaluric conditions and that, in all likelihood, macrophages and multinucleate giant cells are involved in that process.

Expression of Tamm-Horsfall protein in stone-forming rat models.

To examine the expression of Tamm-Horsfall protein (THP) and calcium oxalate deposition in three rat models to clarify whether THP plays an active role in crystal formation or whether crystals induce the secretion of this protein. A stone-forming rat model (model 1) with marked tubular dilatation in an entire kidney was produced by rendering Wistar rats (aged 8 weeks) hyperoxaluric and hypercalciuric, through compulsorily feeding with 0.12 mL of 5% ethylene glycol (in two doses daily) and 0.5 microgram of vitamin D3 every other day. Two other rat models were also produced. Model 2 comprised stone-forming rats with minimal tubular dilatation, achieved by giving rats the same dose of ethylene glycol once daily, and model 3 comprised stone-free rats with marked tubular dilatation achieved by unilateral ureteric ligation. The rats' kidneys were resected after 4 weeks and all resected kidneys immunohistochemically stained with an antibody to THP. Simultaneously, the location of calcium oxalate (CaOx) crystals was established with von Kossa staining. The relation between crystals and the secretion of THP was also assessed in vitro. Cultured renal epithelial cells (NRK-52E) were stained with an antibody to THP after they had been cultured for 72 h in a medium containing CaOx crystals. In model-1 kidneys with both tubular dilatation and many crystals, there was local and intense expression of THP in many renal tubules. CaOx crystals and the intense expression of THP tended to occur in the same renal tubules. In model 2 kidneys with little tubular dilatation, only a few renal tubules expressed THP strongly and the location of the crystals rarely coincided with that of THP expression. In model 3 kidneys with marked tubular dilatation but no crystals, THP was expressed strongly in many renal tubules. The expression of THP in cultured NRK-52E cells was not stimulated by CaOx crystals. The results from the in vivo models suggest that THP did not initiate crystal formation and the strong expression of THP was induced not by crystals but by renal tubular damage caused by tubular dilatation. From the close association of THP and crystals in model 1 kidneys, this protein might play a secondary role as an adhesive, promoting stone formation.

Treatment of Ethylene Glycol Poisoning

In their recent article, Curtin et al 1 probably relied on a computer search to compile their bibliography. While computers and bibliographic software programs speed up literature searching, they do have their own pitfalls; chiefly, that the world's literature begins when the databases were started. Therefore, articles published earlier, are overlooked. I should like to point out that the use of ethyl alcohol to treat ethylene glycol poisoning goes back to 1963 when studies by Peterson et al 2 showed that ethylene glycol is a substrate of alcohol dehydrogenase and that ethyl alcohol inhibits its oxidation, thus preventing the conversion of ethylene glycol to toxic intermediates and oxalic acid. Moreover, in the same article, experiments carried out using squirrel monkeys proved that treatment of these animals with ethyl alcohol after supertoxic doses of ethylene glycol was successful. These studies were the basis for the first effective treatment of humans 3 that

Subacute and Subchronic Toxicity of Ethylene Glycol Administered in Drinking Water to Sprague-Dawley Rats

Subacute (10-day) and subchronic (90-day) toxicity studies of ethylene glycol (EG) were conducted in male and female Sprague-Dawley rats to provide the U.S. Environmental Protection Agency's (EPA) Office of Drinking Water with toxicity data for final preparation of a Health Advisory for the chemical. Ethylene glycol was administered in drinking water at concentrations of 0.5, 1.0, 2.0, and 4.0% for both sexes in the 10-day study. Based on a projected consumption rate of 100 ml/kg/day, the respective doses on a mg/kg/day basis would be 554, 1108, 2216, and 4432. These dose levels were also used in the 90-day study for females, but dose levels for the males in the 90-day study were 0.25, 0.5, 1.0, and 2.0% (227, 554, 1108, and 2216 mg/kg/day). At time of sacrifice necropsies were performed and tissues were prepared for histological evaluation. Blood samples were taken for hematology and clinical chemistry determinations. Body weights were measured weekly. Water and food consumption were determined three times weekly. No mortality occurred in the 10-day study. In the 90-day study 8/10 females and 2/10 males in the high dose group died prior to sacrifice. Body weights were suppressed in a dose response fashion for males and females. Hemoglobin, hematocrit, erythrocytes, and leukocytes were all significantly decreased in female rats receiving 4% EG for 10 days. The most significant histopathological findings, seen predominantly in males, were kidney lesions which included calcium oxalate crystals in tubules and pelvic epithelium; tubular dilation and degeneration; intratubular proteinaceous material; and inflammation in tubules and pelvic epithelium. At the same dose of ethylene glycol, males had more kidney lesions and much higher incidence and severity of lesions than the females.

Pharmacokinetics and biotransformation of diethylene glycol and ethylene glycol in the rat.

1. 14C-Diethylene glycol (DEG), administered orally to rats at 1, 5, and 10 ml/kg, gave elimination half-lives of 6, 6, and 10 h, respectively, from urinary excretion data. Half-logarithmic plots of urinary 14C excretion rates versus time indicated zero-order elimination for the first 9 and 18 h after oral doses of 5 and 10 ml of 14C-DEG/kg, respectively. 14C-DEG urinary elimination kinetics changed into first-order 6, 9, and 18 h after oral doses of 1, 5, and 10 ml/kg, with a half-life of 3 h. 2. After oral doses of 3 and 5 ml ethylene glycol (EG)/kg, half-lives of 4.5 and 4.1 h were estimated from cumulative urinary excretion data for non-metabolized EG. A half-life of 2 h was determined from half-logarithmic plots of urinary excretion rates of non-metabolized EG after the same oral doses of EG. 3. The urinary concentrations of non-metabolized DEG and its metabolite, 2-hydroxyethoxyacetic acid (2-HEAA), determined by high-resolution n.m.r. spectroscopy in the urine of rats doses with DEG were 61-68% and 16-31% dose, respectively. 4. Urinary concentrations of non-metabolized EG and its metabolite, glycolic acid (GA), determined by n.m.r., gave 62-67% for non-metabolized EG and 28.7% for GA following oral doses of EG. 5. Oxidation of DEG and EG in rats was accompanied by a change of urinary pH, reflecting metabolic acidosis. 6. Comparison of the KM for DEG oxidation in vitro by ADH with that of ethanol oxidation, showed a 680-fold difference in substrate affinity. DEG inhibited ethanol oxidation non-competitively, the Ki being 0.44 M.