Nickel concentrations in serum and urine of patients with nickel eczema

Reference intervals for trace elements in the general Danish population and their dependence on serum proteins

Reference intervals that indicate the anticipated results of clinical chemistry parameters in a healthy background population are essential for the proper interpretation of laboratory data. In the present study, we analysed major trace elements in blood samples from 400 randomly selected members of the general Danish population. Reference intervals were established for trace elements in both whole blood and serum, and associations with major plasma transport proteins were investigated. In the case of a statistically significant correlation, a corresponding protein-adjusted reference interval was established for comparison with the unadjusted interval. While several trace elements correlated with albumin, ferritin and transferrin, the overall impact of transport proteins was minor and resulted in only marginal changes in the reference intervals. In conclusion, the updated reference intervals for trace elements can be employed without adjusting for plasma protein concentrations.

Systemic toxicity eliciting metal ion levels from metallic implants and orthopedic devices - A mini review

The metal/metal alloy-based implants and prostheses are in use for over a century, and the rejections, revisions, and metal particle-based toxicities were reported concurrently. Complications developed due to metal ions, metal debris, and organo-metallic particles in orthopedic patients have been a growing concern in recent years. It was reported that local and systemic toxicity caused by such released products from the implants is one of the major reasons for implant rejection and revision. Even though the description of environmental metal toxicants and safety limits for their exposure to humans were well established in the literature, an effort was not adequately performed in the case of implant-based metal toxicology. Since the metal ion concentration in serum acts as a possible indicator of the systemic toxicity, this review summarizes the reported human serum safe limits, toxic limits, and concentration range (μg/L, ppb, etc.) for mild to severe symptoms of six (cardiac, hepatic, neuro, nephron, dermal and endocrine) systemic toxicities for twelve most commonly used metallic implants. It also covers the widely used metal ion quantification techniques and systemic toxicity treatments reported.

Quantification of cobalt and nickel in urine using inductively coupled plasma atomic emission spectroscopy

Cobalt and nickel are micronutrients indispensable for the body, therefore, their use with food or as part of vitamin complexes is necessary to maintain health. As a result, trace cobalt and nickel contents are present in human biological fluids - blood and urine. According to the World Anti-Doping Agency prohibited list, they belong to the group of blood doping preparations - erythropoiesis stimulants. Nowadays, methods for their control in biological fluids are being actively developed to establish reasonable allowable contents of these trace elements in human biological fluids. However, in addition to developing highly sensitive methods for the determination of the total content of cobalt and nickel using ICP-MS and ETAAS, the development and comparison of various sample preparation methods that can provide the greatest accuracy, reproducibility and express analysis are also relevant. In the present paper, a comparison of different sample preparation methods - direct analysis, dilution and microwave mineralization of urine samples was shown, the detection and quantification limits were compared, some metrological characteristics that can be achieved using these sample preparation methods were evaluated. The procedure was tested on artificial and real urine samples. Taking the course of vitamin complexes in therapeutic concentrations was shown not to lead to a significant increase in the concentrations of analytes in urine, while taking elevated concentrations (for example, 2-fold) makes it possible to determine them even using ICP-AES. However, even in this case, cobalt and nickel concentrations remain at a relatively low level, not able to lead to a significant increase in erythropoiesis.

Genotoxic Effects Due to Exposure to Chromium and Nickel Among Electroplating Workers

Using chromium and nickel for electroplating is important in many industries. This process induces variable adverse health effects among exposed workers. The aim of this study is to detect the genotoxic effects of combined exposure to chromium and nickel among electroplating workers. This study was conducted on 41 male workers occupationally exposed to chromium and nickel in the electroplating section of a factory compared to 41 male nonexposed individuals, where full history and clinical examination were performed. Laboratory investigations included measurement of serum chromium, nickel, 8-hydroxydeoxyguanosine (8-OHdG), and micronuclei were measured in buccal cells. In exposed workers, serum chromium ranged from 0.09 to 7.20 µg/L, serum nickel ranged from 1.20 to 28.00 µg/L, serum 8-OHdG ranged from 1.09 to12.60 ng/mL, and these results were statistically significantly increased compared to nonexposed group ( P < 0.001). Electroplaters showed higher frequencies of micronuclei in buccal cells when compared to nonexposed (ranged from 20.00 to 130.00 N/1,000 versus 2.00 to 28.00 N/1,000; P < 0.001). Linear regression models were done to detect independent predictors of 8-OHdG and micronucleus test by comparing exposed and nonexposed groups. The model found that exposure to chromium and nickel increases serum 8-OHdG by 4.754 (95% confidence interval [CI]: 3.54-5.96). The model found that exposure to chromium and nickel increases micronucleus by 35.927 (95% CI: 28.517-43.337). Serum 8-OHdG and micronucleus test in buccal cells were increased with combined exposure to chromium and nickel. The current research concluded that workers exposed to nickel and chromium in electroplating industry are at risk of significant cytogenetic damage.

Synthesis and evaluation of the complex-forming ability of hydroxypyranones and hydroxypyridinones with Ni (II) as possible inhibitors for urease enzyme in Helicobacter pylori

The complex-forming ability of 2-methyl-3-hydroxypyran-4-one (1a), 2-ethyl-3-hydroxypyran-4-one (1b), 1,2-dimethyl-3-hydroxypyridin-4-one (4a) and 1-ethyl-2-methyl-3-hydroxypyridin-4-one (4b) with nickel(Ni(II)) were characterized by infrared, ultraviolet, proton nuclear magnetic resonance spectroscopy and melting point. The mole-ratio of nickel:ligands was analyzed by atomic-absorption-spectrometry. The partition-coefficients (K_OW) of the compounds were also determined. The binding of ligands with Ni(II) are through deprotonated hydroxyl group (-O^-, disapeared at 3259 cm^-1) and ioan-pairs of carbonyl group (=CO^., shifted from 1650 to 1510-1515 cm^-1). The characterization of complex geometry for bis-(2-methyl-3-hydroxypyranonato)Ni(II) (5a) and bis-(2-ethyl-3-hydroxypyranonato)Ni(II) (5b) predicted to be square-planer while for bis-(1,2-dimethyl-3-hydroxypyridinonato)Ni(II) (5c) and bis-(1-ethyl-2-methyl-3-hydroxypyridinonato)Ni(II) (5d) distorted to tetrahedral-geometry. Inhibitors of Helicobacter pylori urease are nickel chelators. The compounds 1a, 4a and 4b are likely suitable ligands with complex forming-ability to make complexes of 5a, 5c and 5d with nickel. The K_OW values show the compound 5c with low partition-coefficient is more suitable ligand with lower penetration from GI lumen. Future studies demand to find out the biological activity of developed compounds on H. pylori.

Evaluation of raw soapstone (steatite) as adsorbent of trace elements present in Brazilian spirits

The impact of soapstone (steatite) upon inorganic element contaminant concentrations in alcoholic beverages was investigated. Concentrations of As, Cd, Cu, Ni and Pb levels in 8 Brazilian spirits plus an alcoholic simulant were initially measured, and then measured following each 24h cycle of exposure to raw soapstone cups, for a total of 4 cycles/sample. The results were compared to the levels established by Brazilian and German regulations. The contact between the spirits and the soapstone reduced the Cu content by up to 50.4% and increased the Ni content by up to 622.2%, especially in the first contact cycle. The exposure of spirits to the soapstone exhibits a linear reduction in the Pb content (18.3-54.5%) while As and Cd levels remained unaltered throughout the experiments. In conclusion, crude soapstone in contact with alcoholic solutions acts as an adsorbent of trace elements (Cu and Pb) while releasing Ni.

Novel insights into nickel import in Staphylococcus aureus: the positive role of free histidine and structural characterization of a new thiazolidine-type nickel chelator

Staphylococcus aureus possesses two canonical ABC-importers dedicated to nickel acquisition: the NikABCDE and the CntABCDF systems, active under different growth conditions. This study reports on the extracytoplasmic nickel-binding components SaNikA and SaCntA. We showed by protein crystallography that SaNikA is able to bind either a Ni-(l-His)2 complex or a Ni-(l-His) (2-methyl-thiazolidine dicarboxylate) complex, depending on their availability in culture supernatants. Native mass spectrometry experiments on SaCntA revealed that it binds the Ni(ii) ion via a different histidine-dependent chelator but it cannot bind Ni-(l-His)2. In vitro experiments are consistent with in vivo nickel content measurements that showed that l-histidine has a high positive impact on nickel import via the Cnt system. These results suggest that although both systems may require free histidine, they use different strategies to import nickel.

Determination of Pb (Lead), Cd (Cadmium), Cr (Chromium), Cu (Copper), and Ni (Nickel) in Chinese tea with high-resolution continuum source graphite furnace atomic absorption spectrometry

The contents of lead, cadmium, chromium, copper, and nickel were determined in 25 tea samples from China, including green, yellow, white, oolong, black, Pu’er, and jasmine tea products, using high-resolution continuum source graphite furnace atomic absorption spectrometry. The methods used for sample preparation, digestion, and quantificational analysis were established, generating satisfactory analytical precisions (represented by relative standard deviations ranging from 0.6% to 2.5%) and recoveries (98.91–101.32%). The lead contents in tea leaves were 0.48–10.57 mg/kg, and 80% of these values were below the maximum values stated by the guidelines in China. The contents of cadmium and chromium ranged from 0.01 mg/kg to 0.39 mg/kg and from 0.27 mg/kg to 2.45 mg/kg, respectively, remaining in compliance with the limits stipulated by China’s Ministry of Agriculture. The copper contents were 7.73–63.71 mg/kg; only 64% of these values complied with the standards stipulated by the Ministry of Agriculture. The nickel contents ranged from 2.70 mg/kg to 13.41 mg/kg. Consequently, more attention must be paid to the risks of heavy metal contamination in tea. The quantitative method established in this work lays a foundation for preventing heavy metal toxicity in human from drinking tea and will help establish regulations to control the contents of heavy metals in tea.

Easter egg hunt dermatitis: systemic allergic contact dermatitis associated with chocolate ingestion

Pediatric systemic allergic contact dermatitis to nickel has previously been reported in association with cocoa. We present four clinical cases of hypersensitivity temporally associated with chocolate consumption at Easter. Clinicians should be aware of the potential for foods high in nickel to provoke patients with known nickel sensitivity and systemic dermatitis.

High frequencies of positive nickel/cobalt patch tests and high sweat nickel concentration in patients with intrinsic atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is classified into extrinsic AD with high serum IgE levels and impaired barrier, and intrinsic AD with low serum IgE levels and unimpaired barrier. Intrinsic AD has a lower frequency of FLG mutations and a higher frequency of circulating Th1 cells, implying that non-protein antigens, represented by metals, may be an exacerbation factor in intrinsic AD.

OBJECTIVE

To investigate metal allergy in intrinsic AD.

METHODS

Enrolled in this study were 86 Japanese AD patients seen in three university hospitals, consisting of 55 extrinsic and 31 intrinsic AD patients. Patch testing was performed, focusing on nickel, cobalt, and chrome, in parallel with other 14 metals. FLG mutations were analyzed in 49 patients (extrinsic, 29; intrinsic, 20). In 17 patients (extrinsic, 12; intrinsic, 5), sweat was collected from the forearms by exercise, and the concentration of nickel was fluorometrically measured.

RESULTS

Nickel, cobalt, and chrome were the major positive metals. Intrinsic AD showed significantly higher percentages of positive reactions than extrinsic AD to nickel (intrinsic 41.9% vs extrinsic 16.4%, P=0.019) and cobalt (38.7% vs 10.9%, P=0.005). There was no significant difference between FLG mutation-bearing and non-bearing patients. The concentration of nickel was higher in the sweat of intrinsic AD than extrinsic AD patients (333.8 vs 89.4ng/g, P=0.0005) and inversely correlated with serum IgE levels.

CONCLUSIONS

Nickel and cobalt allergy may be involved in intrinsic AD. Given that the metals are excreted through sweat, intrinsic AD might be exaggerated by highly metal-containing sweat.

Influence of dietary factors, age and nickel contact dermatitis on nickel excretion

BACKGROUND

Nickel is a frequently detected cause of allergic contact dermatitis. Ingestion of nickel may lead to flares of nickel contact dermatitis.

METHODS

We examined nickel excretion in the urine of 164 female patients with and without nickel contact dermatitis. The associations between age, atopic dermatitis, nickel contact dermatitis and nickel exposure through nutrition (e.g. dietary supplements) and by patch tests were investigated prospectively. Nickel was measured with atomic absorption spectrometry with two different standardized methods.

RESULTS

A nickel detection limit of 0.2 µg/l was exceeded by all samples. The 95th percentiles of urine nickel concentration were 3.77 µg/l (age 18-30 years) and 3.98 µg/l (age 31-46 years). Bivariate analyses pointed to significantly increased nickel excretion with increasing age, ingestion of dietary supplements, drinking of stagnant tap water, and consumption of nickel-rich food. In the multivariate analysis, age and dietary supplements remained significant predictors of high nickel excretion. A non-significant increase in the median concentration of nickel was observed after the administration of conventional nickel patch tests. Patients with atopic eczema showed urine nickel concentrations similar to those in non-atopic controls.

CONCLUSIONS

The 95th percentile of nickel excretion in our study population markedly exceeded the actual reference value of 3 µg/l. Age and consumption of dietary supplements are the most important predictors. The use of stagnant tap water and consumption of nickel-rich food contribute to the total load. These factors should be explicitly mentioned when allergic patients on a low-nickel diet are counselled. In contrast, existing nickel contact sensitization was not more frequent in subjects with higher nickel excretion. Nickel patch testing may cause transient minor systemic nickel exposure. The findings of this study extend our understanding and management of factors associated with nickel allergy.

Contact allergy and human biomonitoring--an overview with a focus on metals

Humans are widely exposed to chemicals. Today, there is an increased acknowledgement of the importance of measuring human and environmental exposures to man-made or refined chemicals. Different approaches have been applied over time, but during the past 25 years, there has been a general trend towards the use of human biomonitoring. A few studies have used human biomonitoring methodology to track contact allergens together with information on patch test reactivity. Hypothetically, the internal load of reactive chemicals might modify the immune response to haptens and the propensity to sensitize and elicit allergic contact dermatitis or develop tolerance. This review offers a general overview of human biomonitoring, including information about its typical application and methodology. Furthermore, studies that have attempted to perform simultaneous biomonitoring and patch testing are reviewed. It is concluded that all studies conducted until the present have focused on one or two routes of exposure (typically skin and oral exposure, but also skin and airway exposure), whereas no studies have investigated all routes at the same time. Also, there is a need for prospective studies, as all epidemiological studies so far have been cross-sectional.

Dual and single memory rod construct comparison in an animal study

STUDY DESIGN

Single- or dual-shape memory metal (nitinol) rods were used to create spinal deformity in a mini-pig model.

OBJECTIVE

To determine the practicality of employing nitinol rods for clinical spinal deformity correction using an animal deformity creation model.

SUMMARY OF BACKGROUND DATA

Nitinol rods can, theoretically, be approximated to curved spines when cooled/malleable, achieving spinal deformity correction on warming and returning to their original (straight) shape. Square cross-sectional rods may allow transverse plane correction. Single-rod constructs could achieve greater deformity correction clinically, whereas dual rods provide lower implant failure risk. The clinical feasibility and potential effectiveness of single versus dual nitinol rod constructs in creating spinal deformity in an animal model was studied.

METHODS

Twenty mature mini-pigs were grouped: single rod with screws locked to the rod, single rod with screws unlocked, dual rods--locked, dual rods--unlocked. Square nitinol rods (80° manufactured curvature) were cooled (-20°C), straightened, placed into multilevel square-headed pedicle screws and warmed (40°C). Serial radiographs followed deformity creation over 12 weeks. Single versus dual rods, locked versus unlocked rods were compared (P<0.01). Computed tomography showed screw placement and fusion (none attempted). Preoperative and 12-week postoperative serum nickel levels were compared (P<0.05).

RESULTS

Scoliotic deformities were created immediately in single and dual rod groups (28°±8°, 26°±7°; P=0.59); locked and unlocked groups (24°±7°, 30°±6°; P=0.08). At final follow-up, there was no difference between single and dual rods (31°±11°, 28°±10°; P=0.58); unlocked rods and locked rods were 34.9°±9.4° and 25.0°±8.1° (P=0.02). No implant failure occurred, however, the aggressive rod contour led to vertebral endplate fractures. Serum nickel 12 weeks post rod placement were unchanged from preop levels (5.1±0.6 μg/L, 4.7±0.2 μg/L, P=0.10).

CONCLUSION

Nitinol rods, reliable in creating spinal deformity in an animal model, could potentially straighten deformed spines. Square rods, facilitated by markedly reduced stiffness when cooled, have the potential to predictably perform axial plane correction.

Prevalence of nickel sensitization and urinary nickel content of children are increased by nickel in ambient air

In a cross-sectional study performed in 2000, an unexpected positive association between nickel (Ni) in ambient air, urinary Ni content and the prevalence of Ni sensitization in a subgroup of 6-yr-old children living near a steel mill was observed. Between 2005 and 2006, in a different and larger study population, we examined if Ni from ambient air or urinary Ni concentration was related to Ni sensitization in children living next to Ni-emitting steel mills. We studied 749 school beginners living in four Ni-polluted industrial areas of North Rhine-Westphalia, Germany. We assessed Ni in ambient air, Ni in urine from children and mothers, and Ni in tap water, conducted patch tests in children (including the NiSO(4)-dilution test) and collected questionnaire data. Statistics were done by linear and logistic regression analyses, adjusted for covariates. At increased Ni concentration in ambient air (unit of increase: 10 ng/m(3)), urinary Ni concentrations rose in both mothers (9.1%; 95% CI: 6.8-11.4%) and children (2.4%; 95% CI: 0.4-4.4%). The prevalence of Ni sensitization in children was associated with increased Ni from ambient air (unit of increase: 18 ng/m(3); odds ratio 1.28; 95% CI: 1.25-1.32) and urinary Ni concentration (unit of increase: 7.1 μg/L; odds ratio 2.4; 95% CI: 1.20-4.48). Ni in ambient air of areas with Ni-emitting factories contributes to internal Ni exposure in residents via inhalation and, furthermore, is a risk factor for the development of Ni sensitization in children.

Dietary intake of nickel and zinc by young children--results from food duplicate portion measurements in comparison to data calculated from dietary records and available data on levels in food groups

The daily dietary intake of nickel (Ni) and zinc (Zn) by 42 young children, 21 boys and 21 girls, from 4 to 7 years of age, living in urban and rural areas of Germany and having different food consumption behaviour, was determined by the duplicate method with a 7-day sampling period. Dietary records were also kept by the children's parents for the 7-day sampling period. Individual reported food items were identified, assigned to food groups and, together with known Ni and Zn concentrations of foodstuffs, daily intake rates were calculated. The same method was used for calculations of the energy, fat, protein and carbohydrate intake rates. The levels in the food duplicates, determined by atomic absorption spectrometry, were in the range of 69-2000 microg Ni/kg(dry weight) (geometric mean (GM): 348) and 7.1-43 mg Zn/kg(dry weight) (GM: 17.5). Daily intake rates based on the 294 individual food duplicate analyses were 12-560 microgNi/d (GM: 92.3) and 1.5-11 mgZn/d (GM: 4.63). The results from the dietary records were 35-1050 microg Ni/d (GM: 123) and 1.7-15 mg Zn/d (GM: 5.35). The results of the daily intake rates from both methods showed a correlation with regard to Zn (r=0.56), but no correlation was found between either the Ni intake rates determined with both methods or between the Ni intake rates measured by the duplicate method and calculated intake rates from the dietary records of energy, fat, protein, carbohydrates or drinking water. In the case of nickel, the discrepancies between the methods lead one to suppose that the main factors influencing Ni intake by food are not directly caused by easily assessable food ingredients themselves. It is possible that other factors, such as contaminated drinking water or the transition of Ni from kettles or other household utensils made from stainless steel into the food, may be more relevant. In addition there are some foodstuffs with great variations in concentrations, often influenced by the growing area and environmental factors. Further, some food groups naturally high in Nickel like nuts, cocoa or teas might not have been kept sufficient within the records. In summary, the dietary record method gave sufficient results for Zn, but is insufficient for Ni. Based on the food duplicate analysis, children living in urban areas with consumption of food products from a family-owned garden or the surrounding area and/or products from domestic animals of the surrounding area had about one-third higher Ni levels in their food than children either living in an urban area or children consuming products exclusively from the supermarket. Only slight differences were found with regard to Zn. Compared to the recommendations of the German Society of Nutrition (DGE) (25-30 microgNi/d and 5.0 mgZn/d), the participants of the study had a clearly increased Ni and, in view of the geometric mean value, a nearly adequate Zn intake. Health risks are especially given with regard to the influence of nickel intake by food on dermatitis for nickel-sensitive individuals.

Metal-responsive gene regulation and metal transport in Helicobacter species

Helicobacter species are among the most successful colonizers of the mammalian gastrointestinal and hepatobiliary tract. Colonization is usually lifelong, indicating that Helicobacter species have evolved intricate mechanisms of dealing with stresses encountered during colonization of host tissues, like restriction of essential metal ions. The recent availability of genome sequences of the human gastric pathogen Helicobacter pylori, the murine enterohepatic pathogen Helicobacter hepaticus and the unannotated genome sequence of the ferret gastric pathogen Helicobacter mustelae has allowed for comparative genome analyses. In this review we present such analyses for metal transporters, metal-storage and metal-responsive regulators in these three Helicobacter species, and discuss possible contributions of the differences in metal metabolism in adaptation to the gastric or enterohepatic niches occupied by Helicobacter species.

Mechanical testing of a smart spinal implant locking mechanism based on nickel-titanium alloy

STUDY DESIGN

Development and testing of a new spinal implant-locking mechanism based on the special properties of nickel-titanium alloy.

OBJECTIVE

To develop a new self-tightening locking mechanism to reduce fretting corrosion at implant junctions.

SUMMARY OF BACKGROUND DATA

All current implant locking involves tightening of a nut against the rod and screw head to form a coupling. Particulate debris is generated, and the coupling becomes loose because of wear between the rod and locking mechanism (fretting). To avoid this fretting, a new locking mechanism with an automatic retightening effect based on the superelastic and shape-memory properties of nickel-titanium alloy has been developed.

METHOD

The new coupling made of nickel-titanium alloy will tightly lock the rod when temperature increases to 50 degrees C (shape-memory effect). If fretting occurs, the coupling will further tighten itself around the rod (superelastic effect). This new coupling is mechanically tested against 4 current implant couplings.

RESULTS

In axial compression, conventional couplings failed between 570 and 740 N, while the new coupling reached 800 N without loosening. In axial rotation, conventional devices failed between 1.8 and 5.3 Nm, while the new coupling reached 6.5 Nm without failure. During testing, the retightening effect could be seen on the force versus displacement plot.

CONCLUSIONS

To our knowledge, the self-tightening coupling is a new concept not previously described and is attributable to the superior superelastic effect of the new coupling. This implant coupling has the potential to be used as a very low profile system and also in nonfusion technologies in which demands on the coupling would not higher without the protection of spinal fusion.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Nickel quantification in serum by a validated sector-field inductively coupled plasma mass spectrometry method: Assessment of tentative reference values for an Italian population

The daily exposure to Ni from food, industrial processes, jewellery and coins makes the determination of Ni in human serum an important way to monitor the health status in non-occupationally exposed subjects. To this end, a method based on sector-field inductively coupled plasma mass spectrometry was developed and validated. The limits of detection (LoD) and quantification (LoQ), sensitivity, linearity range, trueness, repeatability, within-laboratory reproducibility and robustness were the considered issues of the validation process. The uncertainty associated with the measurements was also calculated, according to the Eurachem/Citac Guide. The method LoD and LoQ were 0.03 and 0.09 ng mL(-1), linearity was over two order of magnitude, trueness was -3.57%, and the repeatability and reproducibility showed relative standard deviations equal to 4.56% and 6.52%, respectively. The relative expanded uncertainty was 21.8% at the Ni levels found in the general population. The tentative reference value for serum Ni was 0.466 +/- 0.160 ng mL(-1) with a related interval between 0.226 and 1.026 ng mL(-1).

Determination of some heavy metals and selenium in Sicilian and Calabrian citrus essential oils using derivative stripping chronopotentiometry

This paper aims to bring some novelty about the concentration of some heavy metals and selenium in biological citrus essential oils (CEO) produced in Sicily and Calabria in different crop years. Derivative stripping chronopotentiometry has been used as an accurate, sensitive, and rapid technique for the determination of Cd, Cu, Mn, Ni, Pb, Zn, and Se in hydrochloric acid extracts of CEO; in the optimized electrochemical conditions, detection limits of <1 microg kg(-1) were obtained for all of the studied metals. In particular, the concentrations of metals were determined in biological bergamot essential oils produced in Calabria in 1999 and 2000 and in biological CEO produced in Sicily in 2003 and 2004. The obtained results provided evidence that Mn was the most abundant metal in all of the studied CEO followed by Zn, Ni, Cu, Pb, and Se; Cd concentrations were always lower than the limit of detection (0.6 microg kg(-1)).

Serum levels of nickel and chromium after instrumented posterior spinal arthrodesis

STUDY DESIGN

Cross-sectional study of 37 patients to measure serum levels of nickel and chromium after posterior spinal arthrodesis using stainless steel implants.

OBJECTIVES

To investigate the relationship between factors such as age, gender, pain, time from surgery, length of arthrodesis, and level of arthrodesis to serum metal ion levels after instrumented spinal arthrodesis.

SUMMARY OF BACKGROUND DATA

Measurable levels of metal ions in the serum can be detected after the use of stainless steel implants. There is some evidence to suggest that long-term exposure can potentially be toxic. Posterior spinal arthrodesis with stainless steel implants is a common procedure to treat spinal deformity in the adolescent population; however, the extent of metal ion exposure after posterior spinal arthrodesis is unknown.

METHODS

Patients that underwent posterior instrumented spinal arthrodesis with more than 6 months follow-up were recruited for this study. Patients with altered neurologic function were excluded. Serum levels of nickel and chromium were measured using inductively coupled plasma mass spectrometry. Pain was assessed using the Oswestry questionnaire. Spine radiographs were used to look for evidence of pseudarthrosis. Forty-five patients were approached, and 37 agreed to the questionnaire and blood test. Ten patients were men and 27 were women. Mean age at surgery was 14 years with mean follow-up of 6 years. Statistical correlations between serum metal ion levels and age at surgery, time from surgery, gender, number of segments fused, spinal instrument interfaces, pain, and instrumentation type were assessed.

RESULTS

Abnormally high levels of nickel and chromium above normal levels (0.3 ng/mL for nickel, 0.15 ng/mL for chromium) could be detected in serum after posterior spinal arthrodesis using stainless steel implants. There was a significant inverse correlation between serum nickel (r = -0.61, P < 0.001) and chromium (r = -0.64, P < 0.001) levels and time from surgery. When patients were grouped based on lengths of time from surgery, 0 to 2 years (n = 7), 2 to 4 years (n = 11), and >4 years (n = 8), the mean +/- SD for nickel (ng/mL) was 3.8 +/- 2.6, 1.3 +/- 1.1, and 0.9 +/- 0.8, respectively. Analysis ofvariance revealed significant group differences (P =0.004). Similarly, the chromium levels were 2.7 +/- 2.7, 0.6 +/- 0.4, and 0.3 +/- 0.3, respectively (P = 0.018). Only time from surgery was a significant multivariate predictor of nickel and chromium serum levels. Pseudarthrosis was not seen in this cohort.

CONCLUSIONS

Elevated levels of nickel and chromium can be measured after posterior instrumented spinal arthrodesis. The levels diminish rapidly with time from surgery but still remained above normal levels 4 years after surgery. Long-term implication of this metal ion exposure is unknown and should be studied further.

Determination of Ni (II) in beverages without any sample pretreatment by adsorptive stripping chronopotentiometry (AdSCP)

The purpose of this paper was to use adsorptive stripping chronopotentiometry for the determination of Ni (II) in worldwide consumed beverages without any sample pretreatment, using dimethilglyoxime (DMG) as complexing agent and a glassy carbon mercury film electrode as the working electrode. Ni (DMG)2 complex is adsorbed onto the mercury film at an electrolysis potential of -500 mV for 60 s and then reduced by a -5 microA constant cathodic current. The sensitivity of the method was studied for certified reference water and black tea in the pH range 6.5-11. At pH 9.5 in ammonia buffer, a detection limit of 0.2 microg L(-1) was achieved; the instrumental precision (expressed as rsd %) was 1.5%, and the accuracy, expressed as obtained recoveries both from certified and not certified matrixes, ranged from 93.0 to 95.5 %. The chronopotentiometric analysis executed on commercial beverages provided evidence that black tea samples were the richest source of Ni (II) (1500-3700 microg L(-1)), followed by coffee (100.0-300.5 microg L(-1)); bottled mineral water showed a Ni (II) concentration lower than 4.6 microg L(-1). Among alcoholic beverages, red wines presented the highest content of Ni (II) (55.5-105.0 microg L(-1)). Significant differences were noticed between Ni (II) levels of fermented and distillated alcoholic beverages; moreover, canned cola and beer did not show higher Ni (II) levels with respect to the glass-bottled products.

Experimental systemic contact dermatitis from nickel: a dose-response study

Systemic contact dermatitis is usually seen as flare-up of previous dermatitis or de novo dermatitis similar to allergic contact dermatitis. Although systemic contact dermatitis from medicaments is a well-established entity, the existence of clinically relevant systemic reactions to oral nickel exposure, in particular systemic reactions to nickel in the daily diet, remains controversial. Several studies have shown that oral exposure to nickel can induce systemic contact dermatitis in nickel-sensitive individuals. In most of these studies, however, the exposure dose of nickel used has been considerably higher than the nickel content in the normal daily diet. The aim of the current investigation was to study dose-response dependency of oral exposure to nickel. In a double-blind, placebo-controlled oral exposure trial, 40 nickel-sensitive persons and 20 healthy (non-nickel-sensitive) controls were given nickel sulfate hexahydrate in doses similar to and greater than the amount of nickel ingested in the normal Danish daily diet. The nickel content in urine and serum before and after oral exposure was measured to determine nickel uptake and excretion. The influence of the amount of nickel ingested on the clinical reactions to oral exposure and on nickel concentrations in serum and urine was evaluated. Among nickel-sensitive individuals, a definite dose-response dependency was seen, following oral exposure to nickel. 7 of 10 nickel-sensitive individuals had cutaneous reactions to oral exposure to 4.0 mg nickel, an amount approximately 10 times greater than the estimated normal daily dietary intake of nickel. 4 of 10 nickel-sensitive individuals had cutaneous reactions to 1.0 mg nickel, a dose which is close to the estimated maximum amount of nickel contained in the daily diet. 4 of 10 nickel-sensitive individuals reacted to 0.3 mg nickel or to the amount equivalent to that contained in a normal daily diet, and 1 of 10 reacted to a placebo. None of the 20 healthy controls had cutaneous reactions to 4.0 mg nickel or to a placebo. Prior to oral exposure, there was no measurable difference in the amount of nickel in the urine or serum of nickel-sensitive persons and healthy controls. Following the oral challenge, the nickel content in the urine and serum of both nickel-sensitive and healthy control individuals was directly related to the dose of nickel ingested.