Human & Experimental Toxicology

2′,2′-Difluorodeoxycytidine (gemcitabine), a pyrimidine nucleoside analog, is used therapeutically in the treatment of pancreatic, non-small cell lung, and breast cancer. The cytotoxic effect of gemcitabine is thought to be due to masked chain termination after the triphosphorylated anabolite of the drug is incorporated into nascent DNA strands. We tested the hypothesis that sublethal concentrations of gemcitabine inhibit DNA polymerase γ and reduce mitochondrial DNA content in BxPC-3 and MOLT-4 cell lines, and we used 2′,3′-dideoxycytidine, a known inhibitor of DNA polymerase γ as a positive control. The 6-day BxPC-3 cell growth IC₅₀ for gemcitabine and 2′,3′-dideoxycytidine was 0.003 μM (SD ± 0.0005) and 14.5 μM (SD ± 4.7), respectively, and in MOLT-4 cells was 0.002 μM (SD ± 0.001) and 0.86 μM (SD ± 0.23), respectively. These drug concentrations were anti-proliferative but non-cytotocidal. Electron photomicrographic studies showed deranged mitochondrial cristae patterns in BxPC-3 cells treated with either gemcitabine or 2′,3′-dideoxycytidine for 6 days. Mitochondrial oxidative phosphorylation dysfunction was observed as reflected by increased lactate concentration in the media of cells exposed to gemcitabine, but to a much greater extent in cells exposed to 2′,3′-dideoxycytidine. PCR analysis showed that gemcitabine did not reduce mitochondrial DNA content in either BxPC-3 or MOLT-4 cells, but 2′,3′-dideoxycytidine did. The effect of gemcitabine on mitochondrial ultrastructure and function did not concomitantly yield a reduction in mitochondrial DNA content. Therefore, the molecular target(s) by which gemcitabine and 2′,3′-dideoxycytidine produce mitochondrial abnormalities in these cells appear to be different.

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 ¹⁴C-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.

This study was designed to investigate the effect of oral curcumin pretreatment (200 mg/kg) on isoproterenol-induced myocardial injury in rats. Isoproterenol (85 mg/kg, s.c., in two divided doses at 24 h intervals) administration induced a statistically significant increase (P < 0.01) in serum lactate dehydrogenase, creatine kinase, aspartate transaminase, and alanine transaminase activities and significant increase (P < 0.01) in myocardial lipid peroxides levels as compared to vehicle control rats. Furthermore, significant depletion (P < 0.01) of myocardial endogenous antioxidants viz. superoxide dismutase, catalase, and tissue glutathione levels were also found in the pathogenic control group, that is, isoproterenol only treated animals. Curcumin (200 mg/kg) pretreatment for 20 days in isoproterenol treated rats significantly lowered (P < 0.01) the serum lactate dehydrogenase, creatine kinase, aspartate transaminase, alanine transaminase, and myocardial lipid peroxides levels and increased the levels of myocardial endogenous antioxidants (superoxide dismutase, catalase, and tissue glutathione) as compared to pathogenic control rats. Furthermore, histological examination of rat’s heart section confirmed myocardial injury with isoproterenol administration and near normal pattern with curcumin pretreatment. The results of our study provide clear evidence that the curcumin pretreatment enhances the antioxidant defense against isoproterenol-induced oxidative myocardial injury in rats and exhibit cardioprotective property.

Contamination of arsenic in drinking water is associated with several human diseases including cancer. It has been reported that oxidative stress plays a vital role in arsenic-induced biochemical and molecular alterations. The aim of the present study was to improve the understanding of arsenic-induced oxidative damage to proteins and to DNA and the role of antioxidants such as ascorbic acid and α-tocopherol in alleviating arsenic-induced damages in experimental rats. A significant increase in the levels of protein oxidation, DNA strand breaks, and DNA–protein cross-links was observed in blood, liver, and kidney of rats exposed to arsenic (100 ppm in drinking water) for 30 days. Co-administration of ascorbic acid and α-tocopherol to arsenic-exposed rats showed a substantial reduction in the levels of arsenic-induced oxidative products of protein and DNA. The results of this study support that free radical–mediated toxic manifestations of arsenic and also suggest that ascorbic acid and α-tocopherol supplementation can improve the arsenic-induced molecular alterations.

The roots and rhizomes of Acorus calamus (Family: Araceae) have been used in the ancient systems of medicine for the treatment of various neurological disorders. Of the various methods used for inducing experimental epileptic models, the intracortical administration of ferric chloride (FeCl₃) into sensorimotor cortex induces recurrent seizures and epileptic discharge similar to human post-traumatic epilepsy through the generation of free radicals. The present study focuses on the effect of Acorus calamus on the behavioral, electroencephalographic, and antioxidant changes in FeCl₃-induced rat epileptogenesis. Topical administration of FeCl₃ (5 μL; 100 mM) into the sensorimotor cortex of rats showed an increase in the wet dog shake behavior, spike wave discharges together with an significant increase in antioxidant enzyme activity, such as superoxide dismutase and catalase, resulting in an increase in the level of lipid peroxidation in cerebral cortex. Pretreatment with Acorus calamus (200 mg/kg b.w., p.o. for 14 days) and also diazepam (DZ, 20 mg/kg b.w., i.p.) decreased the WDS behavior, spike wave discharges with single isolated positive waves, and a significant decrease in activity of superoxide dismutase and level of lipid peroxidation was observed in cerebral cortex with respect to those observed in FeCl₃-induced epileptic group. Data presented in this study clearly show that Acorus calamus possesses the ability for preventing the development of FeCl₃-induced epileptogenesis by modulating antioxidant enzymes, which in turn exhibit the potentiality of Acorus calamus to be developed as an effective anti-epileptic drug.

The aim of our study was to evaluate the severity of hepatic and kidney damage with a focus on their reversibility, and to analyze the prognostic factors following Amanita phalloides poisoning based on calls made to the Czech Toxicological Information Centre. A variety of clinical and laboratory parameters were collected. Student’s t-test and Fisher’s test were used for statistical analysis. Amanita phalloides poisoning was verified in 34 cases (5 children, 29 adults). The following findings emerged: vomiting (76%), diarrhea (62%), hepatic failure (24%), and renal failure (11%). Two patients died on the fifth day after mushroom ingestion. In 18 patients, all serum levels normalized by the time of discharge; in 10 patients up to 7.3 months on average after discharge. Five patients did not comply with follow-up. Renal damage persisted in only one patient, 19 months after discharge. In conclusion, the interval to recovery from hepatic and renal damage by the time of discharge depended on a decrease in the prothrombin index and an increase in serum transaminase and bilirubin levels. Recovery was favorable in all subjects who survived the acute phase of poisoning, except in one patient with a solitary kidney.

Organophosphorus compounds are known to cause the selective release of liver microsomal β-glucuronidase into plasma. Organophophoruses may induce nitrosative stress leading to the generation of nitrogen free radicals and alterations in scavengers of free radicals in many biological systems. In this study, we investigate how acute human organophosphorus intoxication is associated with changes of blood nitric oxide, total thiol molecules, and activities of the acetylcholinesterase and β-glucuronidase. A total of 21 acute organophosphorus-poisoned patients were recruited into study and were divided into two groups of mildly (13) and severely affected (9); 26 age-matched healthy volunteers were recruited as control group. Results indicated that both mildly and severely affected patients had lower acetylcholinesterase activities as compared to controls. The extent of acetylcholinesterase reduction in the severely affected patients was higher than that of mildly affected patients. A significant increase in serum β-glucuronidase was observed only in severely affected patients as compared to controls. Both mildly and severely affected patients had lower plasma total thiol molecules as compared to controls. The extent of reduction of total thiol molecules in the severely affected patients was higher than that of mildly affected patients. No significant difference was observed in plasma total nitric oxide of controls and patients. It is concluded that nitrosative stress has a minor role in toxicity of organophosphorus, whereas blood β-glucuronidase is very sensitive biomarker at high exposure of severe organophosphorus poisoning.

Two cases of acute valproic acid poisoning with central nervous system depression and raised ammonia level without hepatotoxicity were reported. They were treated successfully with the use of the antidotes: l-carnitine and other supportive measures. Clinical manifestation and progress was described, and discussion is focused on the use of l-carnitine in valproic acid–induced hyperammonemia, from its mechanism to the clinical experiences in the literature. Based on the favorable response of our two cases and the literature review, we recommend the administration of intravenous l-carnitine in patients of valproic acid overdose with hyperammonemia or valproic acid–induced hyperammonemic encephalopathy and hepatotoxicity at a dose of 50 mg/kg every 8 h for the first initial 24 h with further individual assessment.

Bromism, chronic bromide intoxication, can be caused by a variety of medicines, but bromism due to pain-relieving injectable medications has not been reported. In this study, the methods used were internet searching on bromide-containing injectables available in Taiwan and the first case report of bromism due to mixed-formulated injectable medication. Many analgesic/antipyretic and antihistamine injections containing bromides are still being used in Taiwan. They contain sodium bromide up to 1000 mg/ampoule or calcium bromide up to 800 mg/amp. A 25-year-old female suffered from forgetfulness and unstable gait after long-term frequent injections of a preparation to relieve head and neck pain. Blood tests showed hyperchloremia (171 mEq/L) and a negative anion gap (−48.7 mEq/L). Serum bromide measured 2150 mg/L. She recovered completely in 3 days with saline treatment. Many bromide-containing injections are still being used in Taiwan. Clinicians should keep alert on this issue to avoid iatrogenic bromism or making misdiagnoses.

1-Propanol and 2-propanol are isomers of an alcohol with three carbons. They are colorless liquids with a sweet odor. 1-Propanol is metabolized by alcohol dehydrogenase to propionic acid and presents with metabolic acidosis and elevated anion gap, whereas 2-propanol is metabolized by alcohol dehydrogenase to acetone and presents with rapidly developing (within 3–4 h after exposure) ketosis and ketonuria but without metabolic acidosis. We report a patient who simultaneously ingested a lethal dose of 1-propanol and 2-propanol as a hand disinfectant in hospital. The patient lost consciousness and stopped breathing within half an hour after ingestion. He was intubated and artificially ventilated. Initial laboratory results showed mixed acidosis with elevated anion gap, but ketonuria appeared only 12 h after admission and 6 h following the regaining of consciousness. Therefore, laboratory results in simultaneous poisoning with two isomers of alcohol are not just a sum of laboratory results obtained in isolated poisoning with each isomer because they influence each other’s metabolism: 1-propanol retards the metabolism of 2-propanol to acetone. In conclusion, 1-propanol and 2-propanol poisoning presents early with mixed acidosis and elevated anion gap and only later with ketonuria.

There have been no case reports on aluminum phosphide–induced pancreatitis in the literature available. In this report, we present the case of a young man who developed acute pancreatitis and probably acute myocarditis following ingestion of aluminum phosphide pellets in the absence of the usual risk factors and after exclusion of other possible causes of pancreatitis. In the absence of re-challenge, we put forth the probable causative association of pancreatitis with aluminum phosphide or phosphine gas, its active pesticidal component.