Dental Restoration, Permanent ; Humans ; Metal Ceramic Alloys ; adverse effects ; Nickel ; adverse effects

Medical metal materials is widely used in medical field due to its excellent properties; the nickel ions leaching from stainless steel because of corrosion have the harmfulness of malformation and cancerization besides allergenicity in human body. Potential harmfulness of nickel in medical metal materials and new trend on research and development are reviewed in this paper, and both the advantage and the long term potential development of nickel-free medical stainless steels are also described on the basis of our own research work.
Corrosion ; Humans ; Materials Testing ; Nickel ; adverse effects ; chemistry ; Stainless Steel ; chemistry ; Titanium ; adverse effects ; chemistry

Adult ; Electrolysis ; Humans ; Lipid Peroxidation ; drug effects ; Male ; Middle Aged ; Nickel ; adverse effects ; blood ; pharmacokinetics ; Occupational Exposure ; adverse effects

The authors reviewed two patients showing "vitiligo-like depigmentations" where the skin had been in close contact with a metal spectacle frame made of nickel alloy. In spite of the hypersensitivity to nickel in both patients, they showed clinical and histologic findings indicate that the formation of "vitiligo-like depigmentation" does not result from posinflammatory hypopigmentation but from chemical hypomelanosis. We could not explain the underlying mechanisms; however, the speculation that the "vitiligo-like depigmentation" may come from the direct effect of the nickel itself, prompted us to report these cases.
Adult ; Dermatitis, Contact/*etiology ; Human ; Male ; Middle Aged ; Nickel/*adverse effects ; Vitiligo/*chemically induced

OBJECTIVETo analyze the clinical fracture of nickel-titanium instruments and its causes.

METHODS68 Profile and NiTiflex files broken during the clinical root canal instrumentations in two years were collected. The analysis was carried out regarding the relation between the broken files and the distribution in the teeth, canal, degree of curvature of canals, and the relation between amount of the broken files and the period.

RESULTSThe majority of the clinical fracture of nickel-titanium instruments were flexural fatigue which frequently occurred in molar, the midpoint of the curvature, canal with curves > 30 degrees and very complex canals. Amount of the broken nickel-titanium instruments in the first year was twice than that in second year.

CONCLUSIONThe fracture of nickel-titanium instruments is closely related to the anatomy of the root canal, the operator's experience and the usage of instrument and so on.

Dental Instruments ; adverse effects ; Humans ; Nickel ; Root Canal Therapy ; instrumentation ; Titanium

The purpose of this study was to investigate the NOAEL of the nickel ion and provide with basic data for the biological evaluation of those medical devices containing nickel. Five groups SD rats were repeatedly exposed during 14 d respectively to nickel at first stage doses of 4.9, 3.7, 2.5 mg/(kg.d), and the second stage doses of 1.2, 0.25 mg/(kg.d) by the intravenous route. The results showed that the NOAEL of nickel ion is 0.25 mg/(kg.d) for SD rats, and the result was verified by subchronic systemic toxicity test of nickel alloy. The threshold of toxicological concern (TTC) of nickel is 150 μg/d (based on application of 100-fold uncertainty factor and a body weight of 60 kg)deduced by these data.
Animals ; Equipment and Supplies/adverse effects* ; Nickel/toxicity* ; No-Observed-Adverse-Effect Level ; Rats ; Rats, Sprague-Dawley ; Risk Assessment

OBJECTIVETo study the excision repair capacity of human 8-oxoguanine DNA N-glycosylase 1 (hOGG1) for 8-OH-dG and the oxidative DNA damage among workers exposed to nickel in stainless steel production environment.

METHODSA total of 231 workers exposed to nickel in a stainless steel production enterprise were recruited as nickel exposure group, and another 75 water pump workers in that enterprise were recruited as control group. The workplace occupational hazard factors were determined. Double-antigen sandwich ELISA was used to determine urinary 8-OH-dG level; RT-PCR was used to determine hOGG1 mRNA level. Pearson correlation was used to analyze the correlation between urinary 8-OH-dG level and hOGG1 mRNA level.

RESULTSLevel of 8-OH-dG was compared between different types of nickel-exposed workers and control workers; rolling mill workers showed no significant difference from the control group (P > 0.05), while steel making workers and steel slag disposing workers showed significant differences from the control group (P < 0.05). Level of 8-OH-dG was also compared between nickel-exposed workers with different working years and control workers; nickel-exposed workers with 0∼5 and 6∼10 working years showed no significant differences from the control group (P > 0.05), while other exposed workers showed significant differences from the control group (P < 0.05). Different types of nickel-exposed workers all showed significant differences from the control group in hOGG1 mRNA level (P < 0.05). Nickel-exposed workers with 0∼5 working years showed no significant difference from the control group in hOGG1 mRNA level (P > 0.05), while other exposed workers showed significant differences from the control group (P < 0.05). Pearson correlation analysis showed that urinary 8-OH-dG level was positively correlated with hOGG1 mRNA level (r = 0.993) in different types of nickel-exposed workers, and the correlation was significant at α = 0.01 (P < 0.05); urinary 8-OH-dG level also showed a positive correlation with hOGG1 mRNA level in nickel-exposed workers with different working years (r = 0.968), and the correlation was significant at α = 0.01 (P < 0.05).

CONCLUSIONExposure to nickel increases oxidative DNA damage among steel workers, and hOGG1 shows active excision repair capacity for 8-OH-dG.

Adult ; DNA Damage ; DNA Glycosylases ; metabolism ; DNA Repair ; Humans ; Male ; Metallurgy ; Middle Aged ; Nickel ; adverse effects ; Occupational Exposure ; adverse effects ; Stainless Steel ; Young Adult

Metal biomaterials must be biocompatible; especially, when they contact directly with blood, they must be haemocompatible. Now, stainless steel, tantalum and nickel-titanium shape memory metal alloy are normally made into intravascular stands that are used to stretch blood vascular and resume blood circulation. Intravascular stand's haemocompatibility is very important because it directly influences the occurrence of thrombogenesis in blood system. This paper briefly reviews the metal intravascular stand's surface property, interface reaction with blood, structure design and the research of haemocompatibility.
Angioplasty, Balloon, Coronary ; adverse effects ; Biocompatible Materials ; chemistry ; Humans ; Metals ; chemistry ; Nickel ; chemistry ; Stainless Steel ; chemistry ; Stents ; adverse effects ; Surface Properties ; Titanium ; chemistry

OBJECTIVETo observe the effect of crystalline NiS on genome DNA methylation profile in in vitro cultured cells.

METHODS16HBE Cells were treated with crystalline NiS at 0.25, 0.50, 1.00 and 2.00 µg/cm(2) for 24 h and three times at total. DAC treatment was given at 3 µmol/L for 72 h.5-mC immunofluorescence and SssI methyltransferase assay methods were applied to investigate if the hypomethylation of genome DNA involved.

RESULTSThe results of 5-mC immunofluorescence showed that the fluorescence intensity of NiS-treated cells were decreased in some degree, and transformed cells were decreased dramatically. By the SssI methylase assay, an average of (81.9 ± 7.3)% methylated CpG were found in negative control cells. By contrast, (77.9 ± 6.2)%, (75.3 ± 6.8)%, (59.5 ± 4.9)%, (67.4 ± 5.1)% methylated CpG were observed in cells treated with NiS for three times at dosage of 0.25, 0.50, 1.00 and 2.00 µg/cm(2) which were abbreviated as NiS0.25, NiS0.50, NiS1.00, NiS2.00 respectively. The ANOVA analysis results showed that there was a significant difference in the 5 groups above (F = 124.95, P < 0.01). The results of Dunnett-t test showed that the methylated CpG of both group NiS1.00 and NiS2.00 were significantly decreased compared with the negative control group (t values were 7.64, 4.89 respectively, P < 0.01). For methylated CpG, (46.2 ± 4.1)% and (43.6% ± 4.3)% were observed in NiS-transformed cells (NSTC1 and NSTC2) which were dramatically decreased compared with the negative control group (t values were 12.79, 13.56 respectively, P < 0.01).

CONCLUSIONGenomic DNA methylation levels were decreased during NiS induced malignant transformation.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; chemically induced ; DNA Methylation ; drug effects ; Epithelial Cells ; drug effects ; Genome ; Humans ; Nickel ; adverse effects ; chemistry

The aim of this study was to investigate the role of selenoprotein M (SelM) in endoplasmic reticulum stress and apoptosis in nickel-exposed mouse hearts and to explore the detoxifying effects of melatonin. At 21 d after intraperitoneal injection of nickel chloride (NiCl₂) and/or melatonin into male wild-type (WT) and SelM knockout (KO) C57BL/6J mice, NiCl₂ was found to induce changes in the microstructure and ultrastructure of the hearts of both WT and SelM KO mice, which were caused by oxidative stress, endoplasmic reticulum stress, and apoptosis, as evidenced by decreases in malondialdehyde (MDA) content and total antioxidant capacity (T-AOC) activity. Changes in the messenger RNA (mRNA) and protein expression of genes related to endoplasmic reticulum stress (activating transcription factor 4 (ATF4), inositol-requiring protein 1 (IRE1), c-Jun N-terminal kinase (JNK), and C/EBP homologous protein (CHOP)) and apoptosis (B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), Caspase-3, Caspase-9, and Caspase-12) were also observed. Notably, the observed damage was worse in SelM KO mice. Furthermore, melatonin alleviated the heart injury caused by NiCl₂ in WT mice but could not exert a good protective effect in the heart of SelM KO mice. Overall, the findings suggested that the antioxidant capacity of SelM, as well as its modulation of endoplasmic reticulum stress and apoptosis, plays important roles in nickel-induced heart injury.
Animals ; Male ; Mice ; Antioxidants/pharmacology* ; Apoptosis ; Endoplasmic Reticulum Stress ; Melatonin/pharmacology* ; Mice, Inbred C57BL ; Nickel/adverse effects* ; Selenoproteins/genetics* ; Heart/drug effects*