Do Dietary Habits Influence Trace Elements Release from Fixed Orthodontic Appliances?

The objective was to investigate the effect of dietary habits on the release of Cr and Ni ions from orthodontic appliances by hair mineral analysis. Patients (N = 47) underwent electronic questionnaire survey to investigate the effect of dietary habits on Cr and Ni levels in hair. The research was carried out on hair sampled at the beginning and in the 4th, 8th, and 12th months of the treatment. The content of Cr and Ni in the collected samples was determined by ICP-OES. The study showed that consumption of acidic dietary products may have the effect on increasing the release of Cr and Ni ions from orthodontic appliances. The release of Cr from orthodontic appliances in patients who consumed fruit juice, coffee, yoghurt, and vinegar was higher. The coefficients enabling comparison of metal ions release pattern at a given sampling points were defined. The comparison of the coefficients yielded the information on the possible magnification of metal ions released as the result of the additional factor consumption of acidic food or drink that intensifies metal ions release. The following magnification pattern was found for chromium: coffee (7.57 times) > yoghurt (2.53) > juice (1.86) > vinegar (1.08), and for nickel: vinegar (2.2) > coffee (1.22) > juice (1.05). Yoghurt did not intensify the release of nickel. Concluding, orthodontic patients should avoid drinking/eating coffee, yoghurt, fruit juices, and vinegar.

Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China

Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.

A quantitative analysis of aerosols inside an armored vehicle perforated by a kinetic energy penetrator containing tungsten, nickel, and cobalt

These tests were conducted to develop a database that could be used to assess risks to soldiers from exposure to aerosolized metallic particulates when the crew compartment of an Abrams tank is perforated by a kinetic energy penetrator. Quantitative data are reported for aerosols produced by kinetic energy penetrators containing tungsten, nickel, and cobalt. The following are addressed: (1) concentrations and rates of particle settling inside the vehicle, (2) particle size distribution, (3) inhalable and respirable particulates, (4) distribution of aerosol particles by mass, and (5) particle shapes. The scenario described in this report simulates a rare occurrence. The lessons learned, however, highlight a requirement for developing protocols for analyses of metals in body fluids and urine as soon as practical, and also for implementing targeted postdeployment medical surveillance programs that monitor both body burden for respired metals and pulmonary function.

Effects of nickel poisoning on expression pattern of the 72/73 and 94 kDa stress proteins in rat organs and in the COS-7, HepG2, and A549 cell lines

The present study deals with the effects of Ni on the expression level of three stress proteins, namely, the cytosolic HSP72 and HSP73, and the reticulum-associated GRP94. Experiments were carried out on "Wistar'' female rats daily injected with 4 mg NiCl2 per kg body weight for 1, 3, 5, and 10 days. Another set of experiments were carried out using cell lines, derived from the monkey kidney (COS-7), and from human tumors of the lung (A549) and liver (HepG2). Cells were cultured for 4 days in the permanent presence of 100, 200, or 400 microM NiCl2. In control rats, stress proteins pattern was found to be tissue specific: two protein bands of 96 and 94 kDa were immunodetected with the anti-GRP94 antibody in kidney and liver extracts, whereas only the 96 kDa band was present in ovary extracts. HSP73 was present in kidney, liver, and ovary whereas HSP72 was only found in kidney. In kidney of nickel-treated animals, HSP73 and the 96 kDa proteins were overexpressed whereas HSP72 was strongly down regulated. No such effect was observed in liver or ovary. Similarly, in nickel-treated cell lines, HSP72 was downregulated and GRP94 (96 kDa protein) was overexpressed. HSP73 expression appeared moderately increased in A549 cells but decreased in COS-7 cells. Because long-term caloric restriction was reported to reduce free radical generation in cells, the effect of 1 month food restriction (50%) was tested in rats as a possible way to lower oxidative damages induced by Ni. No significant effect on HSP expression was observed.

First Epileptic Seizure Induced by Occupational Nickel Poisoning

Toxic causes of seizures are numerous: alcohol and other substances of abuse, drugs, and industrial and household products. However, in the absence of a clearly suggestive history and/or associated symptoms and signs, identification of the toxic origin of new-onset seizures may be extremely difficult. We report here the case of a patient admitted in our hospital after a single generalized tonic-clonic seizure. The remarkable coincidence that a colleague of his, with whom he was working to clean the same workshop, had been admitted 1 week earlier for respiratory distress, coma, and de novo nonconvulsive focal status epilepticus, led us to consider a possible toxicologic etiology. Urine analysis revealed a high nickel concentration, suggestive of acute nickel poisoning.

Can lung cancer risk among nickel refinery workers be explained by occupational exposures other than nickel?

BACKGROUND

Exposures in nickel refineries represent complex chemical mixtures, but only the effect of nickel has been evaluated quantitatively in epidemiologic studies of nickel workers.

METHODS

For a Norwegian refinery, time- and department-specific exposure estimates were developed for arsenic, sulfuric acid mists, and cobalt in air on the basis of personal measurements and chemical data on raw materials and process intermediates. Exposure to asbestos, as well as employment in high-risk occupations outside the refinery, were assessed. We conducted a case-control study nested in a cohort of refinery workers, with 213 cases (diagnosed 1952-1995) and 525 age-matched controls. We analyzed lung cancer risk, adjusted for smoking, by cumulative exposure and duration of work.

RESULTS

There was a substantial association between cumulative exposure to water-soluble nickel and lung cancer risk. Weaker effects were suggested for exposure to arsenic at the refinery and for occupational exposures outside the refinery for 15 years or more. No detectable excess risk was found for refinery exposure to asbestos or sulfuric acid mists, and no dose-related increase in risk was seen from cobalt.

CONCLUSIONS

Exposure to water-soluble nickel remained the most likely explanation for the excess lung cancer risk in the cohort. Other occupational exposures did not confound the strong dose-related effect of nickel to any appreciable degree.

Nickel-induced oxidative stress in testis of mice: evidence of DNA damage and genotoxic effects

Oxidative stress (OS) mechanisms are speculated to play a significant role in nickel-induced toxic effects and their carcinogenic potency. Although nickel-induced oxidative damage in somatic tissues is well demonstrated, evidence of the involvement of a similar mechanism(s) in nickel-induced testicular dysfunction and associated genotoxic effects is scarce. Hence, the present study aimed to investigate the nickel-induced OS response in testis and the associated genotoxic implications in vivo. Initially, the toxicity profile of nickel chloride was determined in adult albino mice (CFT-Swiss) following administration (intraperitoneal) of single doses. Subsequently, multiple sublethal doses (1.25, 2.5, and 5.0 micromol/100 g of body weight per day for 3 days) were used to characterize effects on testicular histoarchitecture, lipid peroxidation (LPO) in testis (homogenates, microsomal or mitochondrial fractions) and epididymal sperm, DNA damage, induction of apoptosis in testis, and incidence of sperm head abnormalities. Although short-term doses of nickel induced only a minimal LPO response, multiple doses elicited a moderate (15% to 30%) increase in LPO in whole homogenates and higher dose-related increases in both mitochondrial (20% to 50%) and microsomal fractions (25% to 60%). This was associated with a significant increase in DNA damage in the testis as evidenced by increased single-strand breaks (fluorimetric analysis of DNA unwinding assay). Further, at higher doses, nickel-induced apoptosis was demonstrable in the testis biochemically. Although caudal sperm counts determined at all sampling weeks showed no alterations, analysis for head abnormalities revealed a nearly 3- to 4-fold increase in the percentage of abnormal sperms among the nickel-treated males during the first 3 weeks. Furthermore, mating of nickel-treated (2.5 micromol/100 g of body weight per day for 5 days) males sequentially for a period of 5 weeks with untreated females resulted in a significant increase in male-mediated dominant lethal-type mutations (the frequency of dead implantations) during the first 3 weeks, suggesting a stage-specific effect on postmeiotic germ cells. These findings suggest that testicular toxicity of nickel compounds may be related to enhanced production of reactive oxygen species, probably mediated through oxidative damage to macromolecules, including damage to DNA.

[Relapsing facial erysipelas caused by nickel allergy. Significance of allergy diagnostics in ENT practice]

This case report shows a typical complication of allergic contact dermatitis as it is often seen in hand and foot eczema: relapsing erysipelas. To our knowledge the occurrence of such a complication in the face has never been reported. In the case presented, relapsing facial erysipelas were treated four times in a period of 2 years symptomatically without having identified or eliminated the causing allergen. This clearly indicates how important it is to have a sound knowledge of allergology and its diagnostic procedures, especially in ENT-practice.

A diagnostic pearl: the school chair sign

Allergic contact dermatitis (ACD) reactions to nickel have pleomorphic presentations owing to the ubiquity of this allergen in the environment. In children, ACD to nickel classically occurs on the earlobes, neck, wrists, and infraumbilical area. We describe a newly recognized presentation for this common childhood ACD--on the posterior thighs--which we have termed the school chair sign.

Activity and heavy metal resistance of non-specific esterases in leaf beetle Chrysomela lapponica from polluted and unpolluted habitats

We compared the general activity and heavy metal resistance of non-specific esterases in two populations of the leaf beetle Chrysomela lapponica from habitats severely contaminated by heavy metals (mostly Ni and Cu) and two populations from unpolluted habitats. Concentrations of Ni and Cu in adult beetles from the most polluted site were 7.7 and 3.6 times higher that in beetles from unpolluted habitats. Larval esterases showed higher activity and lower susceptibility to heavy metals than esterases of adults. Larval esterase activity did not differ between populations from polluted and unpolluted sites, but adult beetles from polluted localities had lower esterase activity than beetles from unpolluted habitats. Both Cu and Ni sulfates in millimolar concentrations in vitro suppressed esterase activity of larvae from unpolluted habitats, but caused no negative effect on esterases of larvae from polluted sites. Similarly, inhibition of adult esterase activity by Ni was stronger in beetles from unpolluted localities than in beetles from polluted localities. This indicates that resistance of non-specific esterases to heavy metals is higher in leaf beetle populations from contaminated environment.

Distribution of nickel in lungs from former nickel workers

OBJECTIVE

The purpose of this work was to study the distribution of nickel within lung tissue obtained from nickel-exposed people and to evaluate the use of only one single sample for determination of the nickel burden of the lung.

METHODS AND MATERIALS

The material used was lung tissue obtained from 15 former nickel refinery workers who had been exposed to a variety of nickel compounds such as Ni3S2, NiO, Ni0, NiSO4, and NiCl2. Ten samples taken from different locations of the lung as well as from the right and left bronchus and from the right lower lobe (total 13 samples per individual) were analyzed for nickel by electrothermal atomic absorption spectrometry. Samples obtained from ten people not connected to the refinery served as a reference group.

RESULTS

The arithmetic mean value +/-SD for nickel concentration was 50+/-150 microg g(-1) dry wt. Biopsies collected on the center of the lower right lobe had an average nickel concentration of 82+/-252 microg g(-1). The average nickel concentration detected in the right and left bronchus was 5.9+/-11.6 and 3.8+/-6.0 microg g(-l), respectively. Lung tissue obtained from ten people not connected to the refinery had an average nickel concentration of 0.74+/-0.44 microg g(-1).

CONCLUSIONS

The significant findings based on log-normal distribution of the nickel concentration were as follows: (1) samples obtained from the right lung showed no significant difference from samples taken from the left lung-a comparison of the nickel concentration detected in all the lung lobes showed that no single lobe differed from another; (2) the concentration of nickel found in the main bronchus of the refinery workers, although elevated, was significantly lower than the concentration detected in the remaining tissue; and (3) one single biopsy did not reflect the nickel burden of the lung.

Persistent neurotoxicity from a battery fire: is cadmium the culprit?

Two train conductors had chest tightness, painful breathing, muscle cramps, and nausea after fighting a fire in a battery box under a passenger coach. Shortly thereafter, they became anosmic and had excessive fatigue, persistent headaches, sleep disturbances, irritability, unstable moods, and hypertension. Urinary cadmium and nickel levels were elevated. Neurobehavioral testing showed, in comparison to referents, prolonged reaction times, abnormal balance, prolonged blink reflex latency, severely constricted visual fields, and decreased vibration sense. Test scores showed that immediate verbal and visual recall were normal but delayed recall was reduced. Scores on overlearned information were normal. Tests measuring dexterity, coordination, decision making, and peripheral sensation and discrimination revealed abnormalities. Repeat testing 6 and 12 months after exposure showed persistent abnormalities. Cadmium and vinyl chloride are the most plausible causes of the neurotoxicity, but fumes from the fire may have contained other neurotoxic chemicals.

Transcutaneous metal absorption following chemical burn injury

A 33-year-old metal refinery worker sustained a 40 per cent TBSA burn injury from a mixture containing acids and salts of nickel and cobalt. High levels of both nickel and cobalt were detected in both serum and urine, necessitating treatment with EDTA, a chelating agent. No detrimental effects of either nickel or cobalt have so far been detected, though the patient is being followed in the long term.

Plasma mass spectrometry as a detector for chemical speciation studies

Inductively coupled plasma mass spectrometry (ICP-MS), when coupled with the unique separating power of various chromatographic techniques, allows the detection of various elements at ultra-trace levels. The investigation of various toxic elements of environmental concern coupling relatively recent techniques, such as supercritical fluid chromatography (SFC) and capillary zone electrophoresis (CZE), to ICP-MS, is discussed. Comparisons have been made with detection limits obtained by using the flame ionization detector. The conventional technique of liquid chromatography for the speciation of vanadium, chromium and nickel is also discussed.

Biochemical renal changes in workers exposed to soluble nickel compounds

1. Biochemical markers of kidney damage were examined in 14 male and 12 female workers highly exposed to soluble nickel compounds in a chemical plant. The results were compared to those obtained in 12 male and 12 female matched controls. 2. The concentration of nickel in urine of male and female workers averaged 5.0 and 10.3 micrograms g-1 creatinine, respectively. The mean duration of exposure in male and female workers was 25 and 15 years. 3. No difference was found in the mean urinary excretion of lactate dehydrogenase, albumin and transferrin in both sexes, total proteins, beta 2-microglobulin (beta 2-m) and retinol-binding protein (RBP) in males and lysozyme in females. Lysozyme and N-acetyl-beta-D-glucosaminidase (NAG) were increased in male and total proteins, beta 2-m, NAG and RBP in female exposed workers. Significant correlations between urinary concentrations of nickel on one side and that of beta 2-m in women (r = 0.462, P = 0.022) and men (r = 0.41, P = 0.018) and of NAG in men (r = 0.405, P = 0.019) on the other side were found in exposed subjects. 4. Results indicate adverse effects of soluble nickel compounds on the kidney tubular function. In agreement with literature data it seems that those effects occur only at high exposure levels.

Interpreting model coefficients when the true model form is unknown

In this paper, we critically examine mathematical modeling. We outline the major assumptions required by modeling methods used in epidemiology and discuss in detail one fundamental assumption that is usually violated in epidemiologic studies: the assumption that the structural model form is correctly specified. We apply concepts from the econometrics literature to examine how epidemiologic inference may be affected when the structural model form is incorrectly specified. Because the structural model is almost always misspecified in practice, tests and confidence intervals for model coefficients do not refer to "true population parameters" in the ordinary sense. Rather, these statistics concern parameters that depend on features of study design, as well as the effects under study. In cohort studies analyzed with multiplicative rate models, model parameters are interpretable as approximations to log standardized rate ratios; unfortunately, such interpretations are not as accurate for other models and designs. We therefore conclude that model coefficients can serve as reasonable effect summaries in some, but not all, situations.

Acute nickel carbonyl poisoning

Nickel carbonyl [Ni(CO)4], is formed when metallic nickel combines with carbon monoxide. It is used in the refining process of nickel and as a catalyst in petroleum, plastic, and rubber production. Nickel carbonyl is considered to be one of the most toxic chemicals used industrially and the magnitude of its morbidity and mortality has been compared to that of hydrogen cyanide. A 46-year-old man presented to the emergency department 24 hours after accidental occupational exposure to nickel carbonyl. He admitted to dermal contamination and inhaling the vapor from his clothing after his respiratory protection was removed. On presentation the patient was alert and oriented, complained of shortness of breath, chest tightness, and paresthesias. Examination revealed decreased breath sounds bilaterally and arterial blood gas PO2 of 39% with calculated O2 saturation of 75%. After face mask O2 at 60% his PO2 increased to 85%. The patient required 60% O2 with continuous positive airway pressure of 5 for 4 days. Disulfiram (Antabuse) was administered for the first 2 days until sodium diethyldithiocarbamate (dithiocarb) was obtained. Disulfiram was used because it is metabolized to two molecules of dithiocarb and is hypothetically of value. Dithiocarb was obtained and continued over the next several days. The patient's urine nickel level on the day of admission was 172 micrograms/dL (normal < 5 micrograms/dL) and a serum level of 14.6 micrograms/dL (normal .26-.46 micrograms/dL). The patient's condition gradually improved over the next 10 days. Nickel carbonyl exposure produces mild transient initial symptoms which are followed within 24 hours by more severe life-threatening events.(ABSTRACT TRUNCATED AT 250 WORDS)

Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis?

In spite of the improved awareness of the potential for nickel, cobalt and chromium to cause skin allergy, the incidence of sensitization to them is generally on the increase, especially for nickel. We review data from the literature and industry on transition metal contamination of consumer products and assess the hazard to man. Consumer products are defined as personal care items and detergent/cleaning products used regularly in domestic work. The analytical data demonstrate that consumer products are a relatively minor source of contact with nickel, cobalt or chromium. The traces found in consumer products will not be the primary cause of sensitization to these metals: levels will be too low and exposure too brief. A person sensitized to these metals has many other more significant sources of daily contact such as earrings, jewelry and metal objects. It is therefore necessary to focus on decreasing the high exposure to these transition metals from other sources rather than on possible trace amounts found in consumer products. Current good manufacturing practice ensures that trace nickel, cobalt and chromium concentrations in consumer products are less than 5 ppm of each metal. It is recommended that this be accepted as a standard for maximum concentrations and that the target should be to achieve concentrations as low as 1 ppm.

Medical findings in nickel-cadmium battery workers

Thirty-eight workers from a factory producing nickel-cadmium and other types of batteries came to us for medical evaluation. They included 21 women and 17 men (seniority 2-20 years, age range 31-63 years), and represented a self-selected subset of 700-900 ever-employed and 200+ recently or currently employed workers in the factory. Thirty-four worked on the nickel-cadmium assembly line. Symptoms and signs included: headache in 34; weakness, fatigue and lassitude in 26; dizziness in 16; pruritus and skin eruptions in 37; gingivitis, teeth loss and caries in 34; nasal congestion, nosebleeds and anosmia in 30; cough, phlegm production, wheezing and shortness of breath in 26; "asthma" in 14; bone pain in 18; urinary frequency, beta 2 microglobulinuria and kidney stones in 17; and sterility or multiple abortions (33) in 8 of 21 women. One additional patient had died from an "amyotrophic lateral sclerosis-like syndrome", while CT scans in six workers revealed brain atrophy. One other worker had leukemia, and two had died from cancer (lung and pancreas). Those who had worked for more than 10 years had more symptoms and signs than shorter-term employees, especially neurological illness, bone pain and urinary tract problems, including beta 2 microglobulinuria. Past blood and urinary cadmium levels were in the range of 1.6-8.7 micrograms/dl and 8-306 micrograms/l, respectively. Our findings indicated that: a) health risks for workers were not confined to the nickel-cadmium assembly line or to older workers, b) hazardous exposures still existed and illness appeared in new workers after a clean-up and intervention program, and c) exposures involved increased risks for renal disease and cancers. Finally, there is a need to control exposures and determine health risks in the full cohort of those ever employed, in the workers' children, and in the surrounding environment (air, ground, water) due to the dumping of waste from the plant.

[The alkaline phosphatase and aminotransferase activity of the blood serum and liver in rats with chronic poisoning by the dust from a mineral wool made of ferronickel slag]

The authors investigated the activity of alkaline phosphatase, alanine- and aspartate-aminotransferases of the blood serum, mitochondria and postmitochondrial fraction of the liver in conditions of administration of mineral cotton from ferronickel slag. It was shown that 1 and 3 months after introduction of mineral cotton dust changes occurred in the activity of these enzymes. Restoration of these enzymes occurred 6 months after introduction of mineral cotton dust.

Therapeutic effectiveness of 2,3,2 tet, cyclam and EDTA in toads exposed to lethal doses of nickel and cobalt

1. In the course of the present investigation, three chelating agents (2,3,2 tet, cyclam or EDTA) were tested for their therapeutic effect on nickel and cobalt poisoned toad. 2. Our results showed that EDTA appears to be superior to the two other ligands, which have been proved to be chemical ligands for Ni and Co in vitro. 3. EDTA was able to prevent disturbances in the activities of serum aspartate and alanine aminotransferases, alkaline phosphatase, total protein, urea, uric acid and blood glucose level. 4. Our results suggest caution in the use of 2,3,2 tet or cyclam in human Ni and Co intoxication.

Serum nickel concentrations in hemodialysis patients with environmental exposure

Nickel was analyzed by electrothermal atomic absorption spectrophotometry in serum specimens from 22 healthy hospital workers and 30 patients with end-stage renal disease treated by extracorporeal hemodialysis, who resided in Sudbury, Ontario, Canada, a city with extensive nickel mines and smelters. Samples of tap water from Sudbury contained 109 +/- 46 micrograms Ni per L (P less than 0.01 vs 0.4 +/- 0.2 micrograms Ni per L in corresponding water samples from Hartford, Connecticut). Serum nickel concentrations averaged 0.6 +/- 0.3 micrograms Ni per L in Sudbury hospital workers (P less than 0.05 vs 0.2 +/- 0.2 micrograms Ni per L in corresponding serums from 43 healthy hospital workers in Hartford). In serums collected post-treatment from Sudbury hemodialysis patients, nickel concentrations averaged 8.5 +/- 2.8 micrograms Ni per L, (i.e., 14-times the corresponding mean in Sudbury hospital workers, P less than 0.01), but were not significantly higher than the nickel concentrations in serums from 42 Hartford hemodialysis patients (7.2 +/- 2.2 micrograms Ni per L). This study confirms the presence of hypernickelemia in hemodialysis patients, but does not suggest that hemodialysis patients have significantly increased risk of nickel toxicity in Sudbury, compared to Hartford, despite the high nickel concentrations in Sudbury tap water. This favorable outcome attests to the efficient deionization of water used to prepare hemodialysis solutions in Sudbury.

Acute nickel toxicity in electroplating workers who accidently ingested a solution of nickel sulfate and nickel chloride

Thirty-two workers in an electroplating plant accidently drank water contaminated with nickel sulfate and chloride (1.63 g Ni/liter). Twenty workers promptly developed symptoms (e.g., nausea, vomiting, abdominal discomfort, diarrhea, giddiness, lassitude, headache, cough, shortness of breath) that typically lasted a few hours but persisted 1-2 days in 7 cases. The Ni doses in workers with symptoms were estimated to range from 0.5 to 2.5 g. In 15 exposed workers who were tested on day 1 postexposure, serum Ni concentrations ranged from 13 to 1,340 micrograms/liter and urine Ni concentrations ranged from 0.15 to 12 mg/g creatinine. Ten subjects (with initial urine Ni concentrations greater than 0.8 mg/g creatinine) were hospitalized and treated for 3 days with intravenous fluids to induce diuresis, resulting in a mean elimination half-time (T1/2) for serum Ni of 27 hours (SD +/- 7 hour), which was significantly shorter (p less than .001) than the mean T1/2 of 60 hours (SD +/- 11 hours) in 11 subjects who did not receive intravenous fluids. Laboratory tests showed transiently elevated levels of blood reticulocytes (N = 7), urine albumin (N = 3), and serum bilirubin (N = 2). All subjects recovered rapidly, without evident sequellae, and returned to work by the eighth day after exposure.

Chelation in metal intoxication. XXV: Mercaptoacrylic acids as antidotes of lead and nickel toxicity

beta-1,2-Phenylene di-alpha-mercaptoacrylic acid (1,2-PDMA), beta-1,4-phenylene di-alpha-mercaptoacrylic acid (1,4-PDMA) and alpha-mercapto-beta-(2-hydroxyphenyl) acrylic acid (MHA) were synthesized and compared with 2,3-dimercapto-propane-1-sulfonate (DMPS) for their ability to counteract toxic effects of lead and nickel in rats. 1,2-PDMA and DMPS were most effective in enhancing the excretion of metals, restoring most of the metal induced biochemical alterations and reducing the body burden of the metals; These observations confirm that the chelating agents with two adjacent sulfhydryl groups are better than those with non-adjacent SH groups as metal antidotes. The success of MHA in mobilizing the tissue metals and increasing their urinary excretion indicates participation of the hydroxy group on the benzene nucleus besides the SH group of the MHA molecule, in chelation of the metals.

Evaluation of chelating drugs on the toxicity, excretion, and distribution of nickel in poisoned rats

The effects of various doses of two macrocyclic drugs, namely, 1,4,8,11-tetraazacyclotetradecane (Cyclam) and 5,7,7',12,14,14'-hexamethyl-1,4,8,11-tetraazacyclotetradecane++ + (Cyclam s), on the toxicity, distribution, and excretion of nickel were evaluated in nickel-poisoned rats and compared with the linear counterpart triethylenetetraamine (TETA) and a tripeptide, glutathione (GSH). Cyclam and Cyclam s revealed a higher order of efficacy against the lethal response of nickel even at a lower dose. These drugs significantly enhanced the urinary and biliary excretion of nickel and restored the altered levels of trace metals (viz., Cu, Zn, Fe, Mn) compared to TETA and GSH. The efficacy of these drugs in vivo may be related to their ability to transport nickel across an artificial lipid membrane, a phenomenon was not exhibited by TETA or GSH.

Tin: an overlooked contact sensitizer?

Patch tests with metallic tin in 73 nickel-sensitive patients revealed 6 positive allergic reactions. Only 4 doubtful reactions were seen, which makes irritancy unlikely. The relevance and clinical significance of the unexpected finding deserves further evaluation.

Chelation in metal intoxication. XIX. alpha-Mercapto-beta-aryl acrylic acid as antidotes to nickel and lead toxicity

In view of the reported effectiveness of alpha-mercapto-beta-(2-furyl) acrylic acid (MFA) as an effective antidote to inorganic mercury toxicity, some alpha-mercapto-beta-aryl acrylic acids were synthesized and examined for their efficacy in counteracting nickel and lead intoxication in rats. alpha-mercapto-beta-(3,4-dimethoxyphenyl)acrylic acid (MDA) was most effective and other compounds were less but about equally effective in enhancing urinary excretion and in reducing tissue concentration of Ni. MDA was the only compound to remove Ni from the brain. MFA was also more effective than other structurally related compounds in enhancing urinary and faecal excretion and in lowering body burden of Pb. All the compounds significantly reduced the inhibition of the activity of blood delta-aminolevulinic acid dehydratase (delta-ALA-D) and increase in the urinary excretion of delta-aminolevulinic acid (delta-ALA) caused by Pb. The results do not show any relationship between the nature of the substitution at the beta-position of alpha-mercapto acrylic acids and their ability to reduce the concentration and the toxic effects of the two metals. However, these thiol chelating agents appear promising as antidotes to Ni and Pb poisoning.

Cancer risk of arc welders exposed to fumes containing chromium and nickel

A retrospective follow-up study among chromium- and nickel-exposed welders, which took into consideration welding procedures, duration of exposure, and smoking habits, yielded an increased cancer risk in a comparison with an internal reference group of turners, milling cutters, and drillers, as well as in a comparison with the general population of the Federal Republic of Germany. Due to the cohort size (1 224 welders, 1 694 turners) and the fact that the observation period is still too short, confirmed statements as to the target cancer sites cannot yet be made. However, it emerges that welding with coated electrodes shows a higher cancer risk as compared to the other welding processes observed. This finding may be explained by the fact that the share of hexavalent chromium compounds in the welding fumes is greater with coated electrodes than with other processes so that a follow-up study observing the health risks of chromium and nickel fumes separately would be warranted. For the confirmation of a more favorable outcome with gas-shielded welding, a larger investigation group or a longer observation period would be required.

Nickel influences iron metabolism through physiologic, pharmacologic and toxicologic mechanisms in the rat

A study involving three experiments was done to ascertain whether the beneficial effect of nickel on hematopoiesis in moderately iron-deficient rats was due to physiologic and/or pharmacologic mechanisms. Female Sprague-Dawley rats were fed nickel supplements ranging from 0 to 100 micrograms/g in iron-low (15 micrograms Fe3+/g), iron-adequate (65 micrograms Fe3+/g), or iron-luxuriant (100 micrograms Fe3+/g) diets. The basal diet contained from 2 ng (experiment 3) to 36 ng (experiment 1) of nickel/g. At 10 weeks, both nickel deficiency and toxicity (100 micrograms/g diet) tended to depress hematopoiesis and markedly altered femur and liver trace element content in marginally iron-deficient rats. The alterations included elevated copper, iron and nickel, and depressed calcium and manganese in femurs. The pharmacologic action of nickel was indicated by the finding that high dietary nickel (5, 10, 20 or 50 micrograms/g) apparently stimulated hematopoiesis in marginally iron-deprived rats to a greater extent than dietary levels of nickel (0.1, 0.5 or 1.0 microgram/g) considered adequate for nutritional needs. High dietary nickel also elevated the iron content in liver of marginally iron-adequate rats. The findings indicate that nickel influences iron metabolism at physiologic, pharmacologic and toxic levels of intake. They also indicate that many previously reported signs of nickel deprivation, including effects on hematopoiesis, may have been misinterpreted and might be manifestations of pharmacologic actions of nickel.

Urinary and fecal elimination of nickel in relation to air-borne nickel in a battery factory

Nickel in urine and in air from the breathing zone of 18 male workers in a battery factory was determined weekly during 11 consecutive weeks. The study started immediately following three weeks of Christmas vacation. The nickel levels in air varied but did not increase with time. The average urinary excretion of nickel showed an increase during the first weeks, after which a steady state seemed to have been reached. There was a considerable individual variation in both exposure levels and urine nickel levels. However, a correlation between the averages of nickel in air and urine could be demonstrated on a group basis. In a second study, during one week, measurements of nickel in air and feces were made on 15 of the workers. A significant correlation was found between nickel in air and fecal nickel. Smoking habits did not seem to influence neither urinary nor fecal nickel concentrations.

Chelation therapy in nickel poisoning

For the treatment of acute poisoning from the inhalation of nickel carbonyl, sodium diethyldithiocarbamate (Dithiocarb) has proved to be a specific antidote; tetraethylthiuram (Antabuse) is effective to a lesser degree; d-penicillamine and dimercaprol (BAL) have limited therapeutic value. For the treatment of nickel eczema and dermatitis, favorable response has been obtained by placing patients on a diet of low nickel content together with the oral administration of Dithiocarb or Antabuse. No specific therapy has been advanced for the treatment of nickel cancer in humans. In experimental animals, Dithiocarb has an inhibitory effect on the production of rat rhabdomyosarcomas induced by the intramuscular implantation of nickel subsulfide, and N-methyl formamide inhibits the growth of transplantable nickel fibromas in rats. It is suggested that for the treatment of tumors arising from the implantations of nickel-containing prostheses in humans, chelation therapy be considered.

Relative efficacy of chelating agents as antidotes for acute nickel(II) acetate intoxication

The relative efficacy of 14 chelating agents in alleviating acute nickel(II) acetate (ip) intoxication has been determined. The LD50 for ip nickel(II) acetate in mice was found to be 45.7 mg/kg with a 95% confidence limit of 39.2--53.3 mg/kg. For a level of 62 mg/kg ip of nickel(II) acetate (i.e. approximately LD90 or greater), the most effective antidotes were D-penicillamine and Na2CaEDTA, but several other chelating agents with rather different arrangements of donor atoms were almost as effective. The acetylation of the amino group in penicillamine to give N-Acetyl-D,L-penicillamine effectively destroys the antidotal action, as would be expected if coordination to the nitrogen were essential to the process.

Asbestos as a cofactor in carcinogenesis among nickel-processing workers

It has been widely assumed, especially in the absence of other explanations, that lung cancer and nasal sinus cancers observed among nickel smelter workers are the result of the carcinogenicity of nickel. Although there may be such influence, supplementary hypotheses are also possible. The nickeliferous ores from at least one major smelter in New Caledonia (excess numbers of cancers have been found in these smelter workers) are derived from serpentinized host rocks which contain large amounts of chrysotile asbestos. Analysis indicates that nickel ores from this area are heavily contaminated by these fibers. The deposits are mined for their nickel content, but workers may be exposed to the asbestos fibers contained in the deposits. Hygiene measures limited to the avoidance of nickel may be inadequate under such circumstances and should be reevaluated so as to prevent the inhalation of asbestos-containing dusts.