The Krümmel (Germany) Childhood Leukaemia Cluster: a review and update.

The debate surrounding possible adverse health effects from the civil use of nuclear power under normal operating conditions has been on-going since its introduction. It was particularly intensified by the detection of three leukaemia clusters near nuclear installations, i.e. near the reprocessing plants in Sellafield and Dounreay, UK, and near the Krümmel nuclear power plant, Germany, the last of which commenced between 1990 and 1991 and was first described in 1992; it continued until 2003, and an elevated risk up to 2005 has been reported in the literature. A number of expert commissions and working groups were set up by the governments of the German federal states of Lower Saxony and Schleswig-Holstein to investigate the possible causes of the cluster. An overview of the many risk factors that were investigated as a possible explanation of the Krümmel cluster is given here, focussing on radiation, but also including other risk factors. Further, results from related epidemiological and cytogenetic studies are described. In summary, the cause of the occurrence of the Krümmel cluster has to be considered as unknown. Further research on the causes of childhood leukaemia is needed, focussing on epigenetics and on gene-environment interaction. An update of the leukaemia incidence around the Krümmel site shows that the incidence rates are now comparable to the average rate in Germany.

Characterization of the clonidine receptor site.

At the cardiac sympathetic nerve terminal the alpha 2-adrenoceptor is presynaptic and appears to be located at an extrasynaptic site. This is suggested by (1) absence of evidence of autoinhibitory feedback at physiologic stimulus levels up to about 50 percent of the maximum chronotropic response in the isolated guinea pig right atrium, and (2) absence of significant competition between clonidine and synaptically released noradrenaline (NA) for the presynaptic site. In the central nervous system (CNS) cardiovascular alpha 2-receptors are probably located at a postsynaptic site in bulbospinal regions of the brain, since they produce effects identical to those of synaptic release of NA. Experiments with the clonidine analog alinidine (ST 567) suggest that there are differences in central receptor type subserving clonidine-mediated baroreflex heart rate and blood pressure changes.

Effects of alinidine (ST 567) on baroreceptor-heart rate reflexes and its interactions with clonidine on the baroreflex and on the sympathetic terminals of the isolated atrium.

Alinidine (ST 567), an N-allyl derivative of clonidine, slowed the heart rate of conscious rabbits by 41 +/- 2.3 (S.E.D.) b/min and reduced mean arterial pressure (MAP) by 6.4 +/- 1.4 mmHg (P less than 0.001). The cardiac slowing was considered to be a direct effect in agreement with previous findings by others, since it was present in rabbits without functioning autonomic nerves, but the fall in blood pressure did not occur in these animals. Alinidine produced no significant changes in the reflex tachycardia response evoked by infusing nitroprusside, or in the pressure-related parameters of the MAP-heart period (HP) curve of the baroreceptor-heart rate reflex (i.e. HP range, gain, or median blood pressure BP50). Intravenous (i.v.) clonidine produced characteristic rises in baroreflex HP range and gain, which were due to vagal facilitation, and also produced falls in BP50 and resting MAP. I.v. alinidine suppressed the clonidine-induced vagal facilitation, but had no effect on the blood pressure changes. Intracisternal alinidine could be given in only relatively low dose, but reduced the clonidine-induced rise in vagal component of HP range. The main site of antagonism between i.v. alinidine and clonidine was probably in the CNS. We studied the nature of the antagonism at the sympathetic nerve terminal of the isolated left guinea pig atrium. Clonidine depressed the inotropic response to field stimulation of the sympathetic nerves and this was competitively antagonised by phentolamine greater than yohimbine greater than alinidine at potencies of about 1200:80:1. Alinidine was considered to be a weak but specific alpha 2-antagonist; it has no alpha 1-antagonist properties since it was without effect on the contractile response to noradrenaline of the guinea pig aorta. The alpha 2-antagonist property explains the suppression by alinidine of the clonidine-induced facilitation of the vagal component of the baroreceptor-heart rate reflex.

Developmental neurotoxicity of polychlorinated biphenyls (PCBS): cognitive and psychomotor functions in 7-month old children.

Neurobehavioral effects of polychlorinated biphenyls (PCBs) at environmental levels of exposure have been reported in cross-sectional and prospective studies in infants and children. However, observations differ for effect spectrum, persistence and effective matrix (cord plasma, maternal plasma or milk). In order to improve risk assessment by clarifying some of these uncertainties, a European multicentric study was set up. Results from the German (Düsseldorf) cohort covering 171 healthy mother-infant pairs are given. The sum of PCB congeners 138, 153 and 180 (sigma PCB) in cord plasma and maternal milk was used to describe neonatal PCB exposure. Mean sigma PCB-concentrations were 0.55 ng/ml in cord plasma and 427 ng/g fat in breastmilk. This report covers the Bayley II mental (MDI) and psychomotor development index (PDI) as well as the Fagan Test of Infant Intelligence (Visual Recognition Memory) taken at 7 months of age in relation to neonatal sigma PCB. After confounder-adjustment significant negative associations were found between sigma PCB in milk and MDI (P < 0.05), whereas the other associations proved insignificant.

Long term exposure to manganese in rural well water has no neurological effects.

BACKGROUND: There is debate on the neurological impact of chronic exposure to Manganese (MN). METHODS: MN burden from rural well water was studied cross-sectionally in two proband cohorts from rural dwellings located in northern Germany. Both cohorts had exposure times for up to 40 years and were separated on the basis of well water MN content. Group A (41 subjects; mean age 57.5 years) was exposed to MN water contents of at least 0.300 mg/l (range 0.300 to 2.160), while group B (74 subjects; mean age 56.9 years) was exposed to concentrations of less than 0.050 mg/l. Both proband groups were homogenous with regard to age, sex, nutritional habits, and drug intake. Neurological assessments by clinical investigators blinded for proband's exposure status was done using structured questionnaires, standardized neurological examination with assessment of possible Parkinsonian signs by the Columbia University Rating Scale, and instrumental tests of fine motor coordination. RESULTS: No significant difference in any neurological measure was found between groups. Results were not confounded by demographic and dietary features. CONCLUSION: Exposure to high body burden of MN does not result in detectable neurological impairment. Exposure to MN in drinking water does not seem to be a risk factor for idiopathic Parkinson's disease.

Behavioral effects following single and combined maternal exposure to PCB 77 (3,4,3',4'-tetrachlorobiphenyl) and PCB 47 (2,4,2',4'-tetrachlorobiphenyl) in rats.

The present study has compared the neurobehavioral effects of two structurally different PCB congeners or their combination in rats. Time-mated Long-Evans rats received daily injections of the coplanar PCB 77 (3,4 3',4'-TCB: 0.5 or 1.5 mg/kg), the di-ortho-chlorinated PCB 47 (2,4,2',4'-TCB: 1.5 mg/kg) or a congener mixture (0.5 mg/kg PCB 77 + 1.0 mg/kg PCB 47) from day 7 to 18 of gestation. The PCB exposure levels in brain and perirenal fat of dams and offspring were determined by GC/ECD on gestational day 19 (GD 19), postnatal day 21 (PND 21), and PND 45. PCB 77 was accumulated to a smaller degree than PCB 47. On GD 19, PCB 77 was found to a greater extent in the brains of the offspring than in the brains of the dams, whereas the level of PCB 47 was almost the same in dams and offspring. The testing of open-field behavior in male rats on PND 18 and PND 70 revealed an altered distribution of activity with enhanced activity in the inner zone in PCB 77-treated rats compared to all other groups, while the overall activity was not changed. Distance traveled and rearing behavior on PND 340 were elevated relative to controls in all PCB-treated groups, indicating age-related effects of maternal exposure. A step-down passive avoidance task revealed decreased latencies in the PCB 77 and combined exposure groups on PND 80. Only PCB 77-treated animals showed increased latencies on PND 100 on the haloperidol-induced catalepsy test. These results indicate long-term effects of maternal exposure to PCB 77 on emotional and motor functions. At the dose levels used in the present experiments, the two congeners given in combination did not cause additive or synergistic effects. Instead, concurrent exposure to PCB 47 seemed to counteract PCB 77-induced changes in the pattern of activity.

Neurobehavioral deficits associated with PCB in 7-year-old children prenatally exposed to seafood neurotoxicants.

Prenatal exposure to polychlorinated biphenyls (PCBs) was examined by analysis of cord tissue from 435 children from a Faroese birth cohort. Analysis of 50 paired cord blood samples showed excellent correlation with the cord tissue concentration (r=.90). Among 17 neuropsychological outcomes determined at age 7 years, the cord PCB concentration was associated with deficits on the Boston Naming Test (without cues, two-tailed P=.09 not adjusted for mercury; with cues, P=.03), the Continuous Performance Test reaction time (P=.03), and, possibly, on long-term recall on the California Verbal Learning Test (P=.15). The association between cord PCB and cord-blood mercury (r=.42) suggested possible confounding. While no PCB effects were apparent in children with low mercury exposure, PCB-associated deficits within the highest tertile of mercury exposure indicated a possible interaction between the two neurotoxicants. PCB-associated increased thresholds were seen at two of eight frequencies on audiometry, but only on the left side, and no deficits occurred on evoked potentials or contrast sensitivity. The limited PCB-related neurotoxicity in this cohort appears to be affected by concomitant methylmercury exposure.

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology.

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Dietary intake of lead, cadmium, copper and zinc by children from the German North Sea island Amrum.

The dietary intake of metals was studied in seven male and seven female children at the age of 1.5 to 5.3 years living in a remote area of Germany, the North Sea island Amrum. The dietary intake of lead and cadmium was measured by a seven-day-duplicate study using atomic absorption spectrometry. The dietary intake of copper and zinc were calculated from food diaries. The median lead and cadmium intakes were 2.1 micrograms/(kgbw x week) [range: 0.63-5.1 micrograms/(kgbw x week)] and 2.7 micrograms/(kgbw x week) [range: 1.7-4.4 micrograms/(kgbw x week)]. The median daily intake of copper and zinc were 1.1 mg/d (range: 0.54-2.5 mg/d) and 5.7 mg/d (range: 2.7-14 mg/d). Compared to the provisional tolerable weekly intake (PTWI) of 25 micrograms/(kgbw x week) proposed by the WHO the dietary intake of lead was low. The median amounted to 8.5% and the maximum to 20% of the PTWI. The cadmium intake was comparatively high. The median amounted to 39% and the maximum to 63% of the PTWI [7 micrograms/(kgbw x week)]. The median intake of copper was in the range of the values recommended by the German Society of Nutrition (0.7-1.0 mg/d and 1.0-1.5 mg/d for children at the age of 1-< 4 years and 4-< 7 years). Twenty-three percent of the calculated intakes were below these values. The median intake of zinc however did not reach the recommended dietary intake of 7 and 10 mg/d for children at the age of 1-< 4 years and 4-< 7 years.

Organochlorine pesticides and polychlorinated biphenyls in human milk of mothers living in northern Germany: current extent of contamination, time trend from 1986 to 1997 and factors that influence the levels of contamination.

This study reports the concentration levels of PCB, DDT, HCB and beta-HCH in the human milk of women living in northern Germany over a period of 12 years and determines factors that may influence these levels. From 1986 to 1997 more than 3500 milk samples were analyzed for organochlorine compounds. A questionnaire was used to obtain information regarding personal characteristics, life style factors and eating habits. Descriptive statistics of concentration levels were computed to characterize the current extent of contamination. To follow time trends across the years homogeneous subgroups were compared and multiple regression analyses were used to investigate associations between determining factors and specific contaminants. Between summer 1995 and summer 1997 the median PCB concentration level was 0.502 mg/kg, the median DDT level 0.202 mg/kg, the median HCB level 0.065 mg/kg and the median beta-HCH level 0.036 mg/kg, all values expressed on a fat basis. The median concentration levels decreased by 80-90% during the past 12 years and the median PCB levels by 60%. The concentration levels of all substances were positively correlated with maternal age and negatively associated to parity, to the total period of breast-feeding and to a weight increase of mothers before and after delivery. Post-pregnancy BMI was a significant predictor of the likelihood of having higher concentrations for DDT, HCB and beta-HCH and of having lower concentrations for PCB levels. A balanced diet for at least 3 years was related to lower HCB and beta-HCH levels. Women who ate more than 100 g of fish or more than 700 g of meat per week were more likely to have higher PCB and beta-HCH levels or higher HCB levels, respectively. Higher HCB and beta-HCH concentration levels were associated with lower birth weights of female infants.

Identification of germline susceptibility loci in ETV6-RUNX1-rearranged childhood acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology of ALL is believed to be multifactorial and likely to involve an interplay of environmental and genetic variables. We performed a genome-wide association study of 355 750 single-nucleotide polymorphisms (SNPs) in 474 controls and 419 childhood ALL cases characterized by a t(12;21)(p13;q22) - the most common chromosomal translocation observed in childhood ALL - which leads to an ETV6-RUNX1 gene fusion. The eight most strongly associated SNPs were followed-up in 951 ETV6-RUNX1-positive cases and 3061 controls from Germany/Austria and Italy, respectively. We identified a novel, genome-wide significant risk locus at 3q28 (TP63, rs17505102, P(CMH)=8.94 × 10(-9), OR=0.65). The separate analysis of the combined German/Austrian sample only, revealed additional genome-wide significant associations at 11q11 (OR8U8, rs1945213, P=9.14 × 10(-11), OR=0.69) and 8p21.3 (near INTS10, rs920590, P=6.12 × 10(-9), OR=1.36). These associations and another association at 11p11.2 (PTPRJ, rs3942852, P=4.95 × 10(-7), OR=0.72) remained significant in the German/Austrian replication panel after correction for multiple testing. Our findings demonstrate that germline genetic variation can specifically contribute to the risk of ETV6-RUNX1-positive childhood ALL. The identification of TP63 and PTPRJ as susceptibility genes emphasize the role of the TP53 gene family and the importance of proteins regulating cellular processes in connection with tumorigenesis.

Psychosocial factors in the occurrence of environmental intolerances.

The phenomenon referred to as environmental illness, especially multiple chemical sensitivity, is an extremely controversial and puzzling issue. Despite the seeming gestalt of the disease there is no objective measure for diagnosis and pathophysiology. Psychological and psychosocial factors have a significant role in the presentation and prospects of the disease. Medical neglect of the suffering of the patients as well as iatrogenic attribution towards a chemical intoxication might both increase the risk of chronification and social isolation of patients up to a point of no return. Several observations and results from studies with environmental patients and in related fields are presented and discussed with the aim to encourage continuous research and a critical approach towards a phenomenon where the political necessity to decide is more advanced than the ability to understand.

[Formic acid in urine--a significant parameter in environmental diagnosis?]. / Ameisensäure im Urin--ein sinnvoller Parameter der umweltmedizinischen Diagnostik?

Reference intervals of formic acid excretion in urine of healthy occupational unexposed adults were determined. Within the range of specific gravity between 1.016-1.032 g/cm3 normalization by creatinine or gravity is unnecessary. The mean formic acid concentration in urine of female and male adults aged 20-80 years was 21 mg/l +/- 30 mg/l (95. percentile 60 mg/l) with slightly higher values in elder persons. Smoking and dietary habits had no influence on formic acid excretion but age was positively correlated with increased concentrations. An oral methanol intake of 10 mg/kg body weight had no significant impact on urine excretion of formic acid. Excretion in the general population is determined by endogenous metabolism of amino acids, purine- and pyrimidine-bases rather than the uptake and metabolism of precursors like formaldehyde. Hence in contrast to recent recommendations in environmental medicine, formic acid in urine is not an appropriate parameter for biological-monitoring of low level exposure to formaldehyde.

Comparison of the effects of nitroglycerin administered to rats by different routes.

In pentobarbital-anesthetized rats a comparison was undertaken of the blood pressure lowering effect of nitroglycerin (glyceryl trinitrate, GTN) administered by different routes: jugular vein (i.v.), portal vein (p.v.), peritoneal (i.p.), intrajejunal (i.j.), and sublingual (s.l.). The potency of GTN given by these routes was approximately i.v.:s.l.:i.p.:p.v.:i.j. = 100:20--10:10--5:5:5--2.5. Application of GTN to the visceral peritoneum (i.p.) caused a greater and more prolonged lowering of blood pressure than an injection into the portal vein. We conclude that the capacity of the liver to degrade the active agent during the first passage can be overcome and that a blood pressure response to enterally absorbed GTN could be caused by a prehepatic site of action, i.e., on the splanchnic venous system.

[Binding of drugs to artificial plasma substitutes]. / Bindung von Pharmaka an künstliche Plasmaersatzmittel.

The binding of different drugs to plasma proteins as well as the binding to other structures (e.g. dialysis membranes, i.v. delivery sets) is well documented and of therapeutic importance. Colloid solutions of macromolecules are widely used as plasma substitutes and plasma expanders. A possible binding of drugs to these macromolecules was investigated by means of equilibrium dialysis. Benzodiazepines, beta-blockers, cardiac glycosides, local anesthetics, non steroidal antiinflammatory drugs, glibenclamide, phenobarbitone and phenprocoumon (10(-7) in 50 mM tris buffer, pH 7.4) were dialyzed against tris buffer diluted (1:5) commercially available plasma substitutes consisting of hydroxyethyl starch (HES), dextran, gelatine and polyvinylpyrrolidone (PVP). Binding to plasma substitutes was observed with the highest values for penbutolol and oxypolygelatine (41%), digitoxin and HES 200 (35%), phenprocoumon and PVP (43%). It is concluded that the binding of drugs to plasma substitutes is in most cases negligible and not of clinical relevance. Since some drugs seem to bind to some extent to different macromolecules this should be borne in mind and could be of some influence e.g. in perfusion experiments with isolated organs.

Uptake and displacement of [3H]-propranolol and [3H]-chlorpromazine in isolated, recirculating perfused guinea-pig lungs.

The pulmonary uptake of tritium labelled propranolol and chlorpromazine and their displacement by amphiphilic drugs has been studied in isolated guinea-pig lungs. Lungs were perfused by recirculation with 60 ml tyrode solution (carbogen gassed, 37 degrees C, 6% hydroxy-ethyl-starch) at a flow rate of 10 ml/min. In uptake experiments, a steady state was reached within 20 min with 95% of 10(-9) M propranolol and 90% of 10(-9) M chlorpromazine removed from the perfusate. Using 10(-4) M propranolol, a saturation process became evident, whereas no concentration dependency was observed for chlorpromazine uptake. Kinetic analysis revealed similar uptake rates, but different capacities for both compounds. In displacement experiments, 10(-9) M propranolol was displaced by 10(-4) M amphiphilic drugs in the order: chlorpromazine greater than propranolol greater than alprenolol greater than tetracaine. No displacement occurred by practolol, indomethacin or phenylbutazone. The results indicate that the lungs have a large binding capacity for amphiphilic drugs. These compounds can interfere with each other, according to their lipophilicity, their steric configuration and charges.

Cimetidine-procainamide pharmacokinetic interaction in man: evidence of competition for tubular secretion of basic drugs.

The hypothesis that basic drugs can compete for active tubular secretion by the kidney was tested in six healthy volunteers by comparing the single dose pharmacokinetics of oral procainamide before and during a daily dose of cimetidine. The area under the procainamide plasma concentration-time curve was increased by cimetidine by an average of 35% from 27.0 +/- 0.3 micrograms/ml X h to 36.5 +/- 3.4 micrograms/ml X h. The elimination half-life increased from an harmonic mean of 2.92 to 3.68 h. The renal clearance of procainamide was reduced by cimetidine from 347 +/- 46 ml/min to 196 +/- 11 ml/min. All these results were statistically significant (p less than 0.016). The area under the plasma concentration-time curve for n-acetylprocainamide was increased by a mean of 25% by cimetidine due to a significant (p less than 0.016) reduction in renal clearance from 258 +/- 60 ml/min to 197 +/- 59 ml/min. The data suggests that cimetidine inhibits the tubular secretion of both procainamide and n-acetylprocainamide, and, if so, represents the first documented evidence for this type of drug interaction in man. The clinical implications from this study necessitate dosage adjustments of procainamide in patients being concomitantly treated with cimetidine. The interaction is pertinent not only for basic drugs that are cleared by the kidney, but also for metabolites of basic drugs and endogenous substances which require active transport into the lumen of the proximal tubule of the kidney for their elimination.

Critical evaluation of current concepts in exposure assessment.

The exploitation of natural resources and the improper use and disposal of thousands of chemicals have resulted in environmental pollution and a potential threat to human health on a global scale. Increasing public concern about environmental exposure to and consequent ill health from contaminants demands informed answers based on valid risk assessment. By assessing internal exposure to pollutants, human biomonitoring focuses on early markers of potential risks to prevent serious adverse effects. Exposure assessment may provide a rational basis for risk assessment, with knowledge of the adequacy of limit values; it may also uncover long-term changes in body burdens and thus help identify the sources and transfer pathways of environmental pollutants. The techniques of biological exposure assessment should be incorporated into epidemiological studies if suitable specimens are available, such as exhaled air, blood, urine, breast milk, or adipose or keratinous tissue. Special precautions must be taken in sampling, storage, and analysis if the findings are to be interpreted correctly and reliable conclusions drawn.

[Burden of DDT, HCH, HCB and PCB in human milk in the former German Democratic Republic. Research and toxicologic evaluation]. / Belastung der Humanmilch in der ehemaligen DDR mit DDT, HCH, HCB, PCB. Untersuchung und toxikologische Bewertung.

The decreasing tendency of the contamination of human milk with residues of organochlorine compounds (DDT, HCH, HCB, PCB) has been confirmed by our investigations also for the territory of the former GDR. Compared with the residue-situation existing in the FRG, the contamination of breast milk with DDT-metabolites 4,4'-DDE and 4,4'-DDT were elevated. A positive correlation was found between age and HCB-exposure, urban residency and 4,4'-DDE, beta-HCH and PCB, and smoking and beta-HCH-residues in human milk.