Frederik A. de Wolff

Effects of dose, sex, and long-term abstention from use on toxic effects of MDMA (ecstasy) on brain serotonin neurons

BACKGROUNDn3,4-methylenedioxymethamphetamine (MDMA or ecstasy) is a popular recreational drug that has been shown to damage brain serotonin neurons in high doses. However, effects of moderate MDMA use on serotonin neurons have not been studied, and sex differences and the long-term effects of MDMA use on serotonin neurons have not been identified. We investigated the effects of moderate and heavy MDMA use, sex differences, and long-term effects of MDMA use on serotonin neurons in different brain regions.nnnMETHODSnBy means of flyers posted in rave venues in Amsterdam, the Netherlands, we recruited 15 moderate MDMA users, 23 heavy MDMA users, 16 ex-MDMA users who had stopped using MDMA for more than 1 year, and 15 controls who claimed never to have used MDMA. We studied the effects of MDMA on brain serotonin neurons using 123iodine-2beta-carbomethoxy-3beta-(4-iodophenyl) tropane ([123I]beta-CIT)-a radioligand that binds with high affinity to serotonin transporters. Density of binding (expressed as a ratio of region-of-interest binding over binding in the cerebellum) was calculated by single-photon-emission computed tomography (SPECT).nnnFINDINGSnWe saw significant effects of group and group by sex (p=0.041 and p=0.022, respectively) on overall [123I]beta-CIT binding ratios. In heavy MDMA users, significant decreases in overall binding ratios were seen in women (p<0.01) but not men (p=0.587). In female ex-MDMA users, overall densities of serotonin transporters were significantly higher than in heavy MDMA users (p=0.004), but not higher than in controls (p=0.524).nnnINTERPRETATIONnOur results indicate that heavy use of MDMA is associated with neurotoxic effects on serotonin neurons, that women might be more susceptible than men, and that MDMA-induced neurotoxic changes in several brain regions of female ex-MDMA users are reversible.

Pharmacokinetics and Toxicity of Bismuth Compounds

SummaryInorganic bismuth salts are poorly soluble in water: solubility is influenced by the acidity of the medium and the presence of certain compounds with (hydr)oxy or sulfhydryl groups. The analysis of bismuth in biological material is not standardised and is subject to large variation; it is difficult to compare data from different studies, and older data should be approached with caution.The normal concentration of bismuth in blood is between 1 and 15 μg/L, but absorption from oral preparations produces a significant rise. Distribution of bismuth in the organs is largely independent of the compound administered or the route of administration: the concentration in kidney is always highest and the substance is also retained there for a long time. It is bound to a bismuth-metal binding protein in the kidney, the synthesis of which can be induced by the metal itself. Elimination from the body takes place by the urinary and faecal routes, but the exact proportion contributed by each route is still unknown. Elimination from blood displays multicompartment pharmacokinetics, the shortest half-life described in humans being 3.5 minutes, and the longest 17 to 22 years.A number of toxic effects have been attributed to bismuth compounds in humans: nephropathy, encephalopathy, osteoarthropathy, gingivitis, stomatitis and colitis. Whether hepatitis is a side effect, however, is open to dispute. Each of these adverse effects is associated with certain bismuth compounds. Bismuth encephalopathy occurred in France as an epidemic of toxicity and was associated with the intake of inorganic salts including bismuth subnitrate, subcarbonate and subgallate. In the prodromal phase patients developed problems in walking, standing or writing, deterioration of memory, changes in behaviour, insomnia and muscle cramps, together with several psychiatric symptoms. The manifest phase started abruptly and was characterised by changes in awareness, myoclonia, astasia and/or abasia and dysarthria. Patients recovered spontaneously after discontinuation of bismuth. Intestinal lavage, forced diuresis and haemodialysis have been tried without positive effects on the clinical condition of the patient or on blood bismuth concentration, and the use of dimercaprol as an antidote has produced reports of both positive and negative findings. To confirm the diagnosis of bismuth encephalopathy, it is essential to find elevated bismuth concentrations in blood, plasma, serum or CSF. A safety level of 50 μg/L and an alarm level of 100 μg/L have been suggested in the past, but no proof is available to support the choice of these levels. The safety level will need to be reconsidered when the analysis and toxicological evaluation of bismuth have been definitively settled. In encephalopathy patients, additional pathological information can be obtained from EEG, CT scan, plain x-ray of the abdomen and postmortem investigations.The bismuth encephalopathy occurred only in France and the surrounding countries, despite extensive use of bismuth elsewhere. A small outbreak of poisoning was also seen in Australian patients who had undergone a colostomy or an ileostomy and taken oral bismuth subgallate. A so far unidentified additional factor besides bismuth was held responsible for these intoxications. Despite many theories on enhanced intestinal absorption, the exact aetiology of bismuth encephalopathy remains a mystery.

Intestinal absorption of aluminum in rats effect of intraluminal ph and aluminum concentration

The intestinal absorption of aluminum (Al) was studied in an in situ perfusion system of rat small intestine in combination with systemic and portal blood sampling. The jejunum‐ileum was perfused with media containing 4.63, 9.25 and 18.50 mmol l−1 Al chloride at pH 4.0 and 7.0. Both mucosal retention and release of Al into the blood increased at increasing perfusate concentrations. Mucosal retention was not affected by pH but at lower pH more Al was released into the blood. The amount of Al which appeared in the blood was linearly related to the mucosal retention. The Al release into the blood was much less (μmol l−1) than the mucosal retention (mmol l−1). It is concluded that the intestinal absorption of Al is pH‐ and concentration‐dependent.

The effect of di- and trivalent iron on the intestinal absorption of aluminum in rats

The effect of iron (Fe) on the intestinal absorption of aluminum (A1) was studied in an in situ perfusion system of rat small intestine in combination with systemic and portal blood sampling. The gut was perfused with media containing 0.0, 10.0, 15.0, 20.0, and 25.0 mmol/liter Al chloride and 5 mmol/liter Fe(II) or Fe(III) chloride at pH 3.0. Neither luminal disappearance nor intestinal absorption of A1 were affected by Fe(III). Fe(II), however, enhanced luminal disappearance and reduced absorption of Al.

A method of studying the intestinal absorption of aluminium in the rat

Aluminium (Al) intoxication in dialysis patients is held to be caused not only by Al in the dialysis fluid but also by Al from orally administered phosphate binders. Studies on Al absorption in patients and healthy individuals as well as in animals are still scarce, and do not provide sufficient data to characterize the absorption process.This paper presents a method of studying the process of Al absorption in a perfusion system of rat small intestine in vivo, in combination with a cannulation system of the portal vein for serial blood sampling. Determination of concentrations of an absorbed substance in samples of both the perfusion medium and the portal blood, collected during the perfusion period, may clarify the nature of the absorption process. Although this method appears to be useful for the study of the intestinal absorption of any substance, it was adapted for the study of the intestinal absorption of Al compounds.The usefulness of this method for studying Al absorption was demonstrated in an experiment in which Al chloride (0.5 g/l) in buffered media of pH 7.0, 7.5, and 8.0 was perfused through the rat small intestine over a period of at least 30 min. The results of this experiment indicate that a decrease in pH of the perfusion medium leads to an increase in absorption of Al in the portal blood.

Subacute fatal aluminum poisoning in dialyzed patients: post-mortem toxicological findings

The population of Curaçao, Netherlands Antilles (133,000) shows a very high prevalence of end-stage renal disease (approximately 1 per 1,000). These patients are often treated chronically with haemodialysis. As the drinking water on the island is prepared by distillation of sea water, the haemodialysis fluid used to be prepared with tap water without further treatment. In 1996, the 27 patients of one of the dialysis centers on the island presented with nausea, vomiting, and hypercalcaemia in a short time span, which was initially diagnosed as hard water syndrome. In spite of treatment with low-calcium dialysate, microcytic anaemia and neurological symptoms developed. Ten patients died of convulsions, sepsis, and coma. As aluminum (Al) intoxication was suspected, Al in serum (AlS) was measured. Ante mortem AlS was 808 microg/l (n = 7; range 359-1189); in the survivors AlS was 255 microg/l (n = 17; range 113-490). Normal AlS is < 10 microg/l, and <50 microg/l in asymptomatic dialyzed patients. The court requested post-mortem toxicological analysis of four patients. Al concentrations in liver, bone, and cerebral cortex were significantly increased as compared with background levels. Al intoxication was, therefore, considered to be the most likely cause of death in these patients. Investigations of the tap water supply revealed that a few weeks before the onset of the symptoms, a water conduit pipe to the dialysis unit had been replaced, which was lined with Al- and Ca-rich cement mortar. These ions leached into the distilled water and caused both Ca- and Al-intoxication through uptake from the dialysate into the patients circulation. The symptoms of the latter were initially not recognized as they were masked by the symptoms of hypercalcaemia.

Bismuth overdosing-induced reversible nephropathy in rats

Abstract. Overdosing of colloidal bismuth subcitrate (CBS), used to treat peptic ulcers and Helicobacter pylori infections, has been reported to result in serious, though reversible, nephrotoxicity in humans. However, little is known about the nature of the renal damage induced by bismuth (Bi), and no well-described experimental model exists. Single large oral CBS doses (0.75, 1.5, and 3.0xa0mmol Bi/kg) were administered to three groups of 20 female Wistar rats. A control group (n=20) received only the vehicle. Standard kidney function parameters, urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) and the Bi content were monitored in blood, urine, liver, and kidneys for 14xa0days. A dose of 3.0xa0mmol Bi/kg, 100 times the daily therapeutic dose, caused kidney damage within 6xa0h as detected by proteinuria, glucosuria, and elevated plasma urea and plasma creatinine levels. The kidneys of all animals, except two that died, recovered functionally within 10xa0days. At a dose of 1.5xa0mmol Bi/kg, clinical parameters changed less and normalized within 48xa0h, whereas a dose of 0.75xa0mmol Bi/kg induced no changes. Histological evaluation revealed that the S3 tubular segment necrotized first with additional necrotization of the S1/S2 segment when more Bi was absorbed. The lesions were accompanied by interstitial infiltrates of CD45+ leukocytes. In summary, we developed a rat model for Bi-induced reversible nephropathy. A large single oral overdose of CBS administered to Wistar rats led to damage to the proximal tubule, especially in the last segment.

Bismuth biokinetics and kidney histopathology after bismuth overdose in rats.

Abstract. Bismuth induced nephrotoxicity has been reported to occur after acute overdoses of Bi-containing therapeutic drugs. We studied the development of bismuth induced nephropathy and bismuth biokinetics in rats. Bismuth nephropathy was induced in 33 young adult female Wistar rats weighing ca. 175xa0g by feeding them a single overdose of colloidal bismuth subcitrate containing 3.0xa0mmol Bi/kg at (t=0). Control animals (n=7) were fed the vehicle only. The animals were sacrificed after 1–48xa0h. Plasma creatinine increased from 51±6xa0µmol/l at t=0 to 550±250xa0µmol/l after 48xa0h in the experimental group. The S3 segment of the proximal tubule showed epithelial cell vacuolation after 1xa0h and necrosis after 3xa0h. Cells of the S1/S2 segment demonstrated vacuolation after 6xa0h and necrosis after 12xa0h. Biokinetics of bismuth in blood could best be described with a one-compartment model characterized by an absorption half-life of 0.32xa0h and an elimination half-life of 16xa0h. The peak concentration of about 7.0xa0mg Bi/l was reached after 2xa0h. In conclusion, cells of the S3 segment of the proximal tubule necrotized first after an oral colloidal bismuth subcitrate overdose and biokinetics of Bi in blood was best described by a one-compartment model.

Analysis of phenprocoumon and its hydroxylated and conjugated metabolites in human urine by high-performance liquid chromatography after solid-phase extraction.

The anticoagulant phenprocoumon is mainly metabolized in humans to hydroxylated metabolites and their glucuronides. A method is described for the determination of phenprocoumon, 4-hydroxyphenprocoumon, 6-hydroxyphenprocoumon, 7-hydroxyphenprocoumon, and their glucuronide and sulphate conjugates in human urine. Reversed-phase high-performance liquid chromatography is performed after selective extraction with disposable quaternary amine columns of untreated, and beta-glucuronidase- or sulphatase-treated urine samples. Urinary excretion data are presented for total, glucuronidated, sulphated and free phenprocoumon, 4-hydroxyphenprocoumon, 6-hydroxyphenprocoumon and 7-hydroxyphenprocoumon in twelve patients after an average daily dosage of 1.3-4.2 mg phenprocoumon.

Renal epithelial gene expression profile and bismuth-induced resistance against cisplatin nephrotoxicity

Nephrotoxicity is the most important dose-limiting factor in cisplatin based anti-neoplastic treatment. Pretreatment with bismuth salts, used as pharmaceuticals to treat gastric disorders, has been demonstrated to reduce cisplatin-induced renal cell death in clinical settings and during in vivo and in vitro animal experiments. To investigate the genomic basis of this renoprotective effect, we exposed NRK-52E cells, a cell line of rat proximal tubular epithelial origin, to 33 mM Bi3 for 12 hours, which made them resistant to cisplatin-induced apoptosis. Differentially expressed genes in treated and untreated NRK-52E cells were detected by subtraction PCR and microarray techniques. Genes found to be down regulated (0.17 / 0.31-times) were cytochrome c oxidase subunit I, BAR (an apoptosis regulator), heat-shock protein 70-like protein, and three proteins belonging to the translation machinery (ribosomal proteins S7 and L17, and S1, a member of the elongation factor 1-alpha family). The only up-regulated gene was glutathione Stransferase subunit 3A (1.89-times). Guided by the expression levels of these genes, it may be possible to improve renoprotective treatments during anti-neoplastic therapies.