Effect of aluminum on bone matrix inductive properties

Ultra-morphology of the scale as an indicator of the stress of Acid Black-1 (AB-1, CI: 20470) and zinc (Zn)

High contents of azo dyes and heavy metals enter surface waters with the wastewater from dying and dye-manufacturing industries and pose serious threat to fish. In the present study, changes in the ultra-morphological features of the scale have been evaluated as indicators of the stress of lethal and sublethal concentrations of an azo dye Acid Black-1 (AB-1, CI 20470), zinc (Zn), and their mixture AB-1 + Zn to Labeo rohita. Fish were exposed for 96 h to lethal concentration (LC) causing 0-70% mortality, i.e., LC₀, LC₂₀, LC₅₀, and LC₇₀ of AB-1 (4, 6, 8, and 10 mg/L respectively) and Zn (25, 50, 55, and 60 mg/L respectively) and LC₀, LC₅₀, and LC₇₀ of AB-1 + Zn (2 + 15, 2 + 20, and 2 + 25 mg/L respectively). Subchronic exposures of 150 days were given to 1/12, 1/6, and 1/3 of 96 h LC₅₀ values of AB-1, Zn, and AB-1 + Zn. After each exposure, the fish were kept for a recovery period of 90 days. Breakage of circuli, erosion and breakage of lepidonts, uprooting of tubercles, and disappearance of intercircular teeth were observed in all the fish, after 96 h exposure to AB-1, Zn, and AB-1 + Zn. However, damage to focus and holes were common on the scales of Zn-exposed fish. The mixture AB-1 + Zn was more toxic than either of the two as loss of circuli, lepidonts, and intercircular teeth, and sloughing of surface were observed in the scales after 96 h exposure to 2 + 25 mg/L. Damage at this concentration was more than the damage at 8/10 mg/L AB-1 and 55/60 mg/L Zn. After 150 days of exposure, damage due to sublethal concentrations was more than the damage due to all the concentrations of 96 h exposure. Irregular and sloughed circuli were common at 2 + 1.79 and 2 + 3.59 mg/L AB-1 + Zn. Cracks all over the surface (2 + 7.18 mg/L), calcium projections (2 + 3.59 and 2 + 7.18 mg/L), and holes (2 + 7.18 mg/L) hint towards synergistic toxicity of the mixture. It seems that the present dye and metal formed complexes with collagen and osteoblastic cells of the scale that caused an increase in damage during the post-exposure period. Scales of 2 + 7.18 mg/L AB-1 + Zn exposed fish were completely devoid of the normal architectural pattern on the 90th day of the recovery period. Changes in the ultra-morphology of scales at LC₀ (0% mortality) and sublethal concentrations show that these are early indicators of the stress of minute quantities of dyes and metals in water. This is a first report on the cumulative toxicity of the two most abundant components of textile industry effluents.

Role of trace elements (Zn, Sr, Fe) in bone development: energy dispersive X-ray fluorescence study of rat bone and tooth tissue

Osteoporosis is one of the most common debilitating disease around the world and it is more and more established among young people. There are well known recommendations for nutrition of newborns and children concerning adequate calcium and vitamin D intake in order to maintain proper bone density. Nevertheless, important role in structure and function of a healthy bone tissue is played by an integration between all constituents including elements other than Ca, like trace elements, which control vital processes in bone tissue. It is important from scientific point of view as well as prevention of bone diseases, to monitor the mineralization process considering changes of the concentration of minerals during first stage of bone formation. This work presents studies of trace element (zinc, strontium, and iron) concentration in bones and teeth of Wistar rats at the age of 7, 14, and 28 days. Energy dispersive X-ray fluorescence (EDXRF) was used to examine mandibles, skulls, femurs, tibiae, and incisors. The quantitative analysis was performed using fundamental parameters method (FP). Zn and Sr concentrations were highest for the youngest individuals and decreased with age of rats, while Fe content was stable in bone matrix for most studied bones. Our results reveal the necessity of monitoring concentration of not only major, but also minor elements, because the trace elements play special role in the first period of bone development.

No association between the aluminium content of trabecular bone and bone density, mass or size of the proximal femur in elderly men and women

Background

Aluminium is considered a bone toxic metal since poisoning can lead to aluminium-induced bone disease in patients with chronic renal failure. Healthy subjects with normal renal function retain 4% of the aluminium consumed. They might thus also accumulate aluminium and eventually be at risk of long-term low-grade aluminium intoxication that can affect bone health.

Methods

We therefore examined 62 patients with femoral neck fractures or osteoarthritis of the hip (age range 38–93), with the aim of examining whether aluminium in bone is associated with bone-mineral density (BMD), content (BMC) or width of the femoral neck measured by dual-energy X-ray absorptiometry (DXA). During operations bone biopsies were taken from the trabecular bone of the proximal femur. The samples were measured for their content of aluminium using a mass spectrometer.

Results

No significant association between the aluminium content in bone and femoral neck BMD, BMC or width could be found after multivariate adjustment.

Conclusion

Our results indicate that the accumulated aluminium content in bone during life does not substantially influence the extent of osteoporosis.

The aluminum content of bone increases with age, but is not higher in hip fracture cases with and without dementia compared to controls

Aluminum is considered a potentially toxic metal, and aluminum poisoning may lead to three types of disorders: aluminum-induced bone disease, microcytic anemia and encephalopathy. This is well known in patients with chronic renal failure, but since healthy subjects with normal renal function retain 4% of the aluminum consumed, they are also at risk of long-term low-grade aluminum intoxication. Included in this study were a total of 172 patients (age range 16-98 years) with the aim of examining whether aluminum accumulates in bone with increasing age. Additionally, we aimed to investigate whether the aluminum content of bone differs between controls and hip fracture cases with and without dementia, in particular in those with Alzheimer's disease. During operations for all cases, bone biopsies were taken with an aluminum-free instrument from the trabecular bone. The samples were measured for their content of aluminum using an inductively coupled mass spectrometer. We found an exponential increase in aluminum content of bone with age. The average aluminum values, adjusted for age, were similar in men and women (P=0.46). No significant differences in sex- and age-adjusted mean aluminum values between the controls and the hip fracture cases with (P=0.72) and without (P=0.33) dementia could be detected. The average aluminum concentration among cases with Alzheimer's disease was also similar to the values of hip fracture patients with other types of dementia (P=0.47). Odds ratios of hip fracture for each quartile of aluminum content in bone were also estimated to detect non-linear effects, but we did not find any statistically significant association remaining after age and sex adjustment. Thus, our results indicate that we accumulate aluminum in bone over our life span, but this does not seem to be of major pathogenetic significance for the occurrence of hip fracture or dementia.

Evaluation of aluminium concentrations in samples of chocolate and beverages by electrothermal atomic absorption spectrometry

Samples of chocolate, cocoa, tea infusions, soft drinks and fruit juice have been examined by, electrothermal atomic absorption spectrometry (ETA-AAS) for the presence of aluminium (Al). Fruit juices and chocolate were analysed after an adequate sample preparation; the other products were evaluated directly. Sampling was performed in duplicate for 248 independent samples. The mean Al concentration in chocolate was 9.2 +/- 7.5 mg kg(-1), and individual values were correlated with the per cent of cocoa in samples (Y = 0.63 + 0.27X, r = 0.78, p < 0.0001). Al concentration in commercial tea infusions ranged from 0.9 to 3.3 mg l(-1) (mean = 1.80 +/- 65 mg l(-1), whereas in laboratory-prepared samples it was 2.7 +/- 0.93 mg l(-1). In soft drinks, the concentrations of Al were lower, ranging from 9.1 to 179 microg l(-1); the highest values were observed in samples of orange squash (mean = 114 +/- 56 microg l(-1)). Apricot juice showed the highest Al level (mean = 602 +/- 190 microg l(-1)), being statistically, different from that of pear (mean = 259 +/- 102 microg l(-1)), but not different from that of peach juice (mean = 486 +/- 269 microg kg(-1)). Toxicologically, the amount of Al deriving from the consumption of these products is far below the acceptable daily intake of 1 mg kg(-1) body weight indicated by the FAO/WHO, and it is a verv low percentage of the normal Al dietary intake.

Determination of trace elements and calcium in bone of the human iliac crest by atomic absorption spectrometry

A rapid and reliable analytical method for the determination of trace elements in human bone by atomic absorption spectrometry is reported. Calcium was determined to estimate the homogeneity of samples. Human bone from the iliac crest was obtained at autopsy of adult subjects. Before analysis samples were decomposed by microwave digestion and acid digestion in a Parr bomb. Zinc, rubidium, strontium, calcium and iron were determined by flame atomic absorption spectrometry (FAAS) and aluminium, copper and lead by electrothermal atomic absorption spectrometry (ETAAS) at optimum measurement conditions. The results for the two digestion procedures agreed for zinc, rubidium and calcium within +/-5%, for copper within +/-7% and for strontium, iron, aluminium and lead within +/-10%. The repeatability of measurement (R.S.D.) for determination of calcium and trace elements after microwave digestion and acid digestion in a Parr bomb was tested in one representative autopsy bone sample by six parallel determinations. It was found to be better than +/-5% either for microwave digested samples or samples digested in a Parr bomb, for all elements determined by FAAS and ETAAS techniques. The accuracy of the applied digestion procedures was checked by analysis of trace elements in NIST SRM 1486 Bone Meal reference material. Good agreement of the results with certified values was obtained for both digestion procedures. The microwave procedure developed for digestion of small amounts of sample was applied in trace elements analysis of bone biopsy samples from dialysis patients.

Measurement accuracy of aluminium content in bone

The aluminium content in bone has been related in several ways: to the weight of wet bone, to the weight of dry bone, to the weight of bone-ash and to the calcium content of bone. We determined the accuracy and precision of measurement (using an inductively coupled mass-spectrometer) in 30 bone samples taken from one patient. The coefficient of variation of the aluminium/weight-quotient was 12.4 per cent for wet bone, 4.7 for dry bone and 5.0 for bone ash; and the coefficient of variation of the aluminium/calcium-weight-quotient was 7.5 per cent. Thus, the aluminium content in bone seems to be best related to the weight of dry bone.

Biocompatibility tests on a novel glass-ceramic system

The aim of this study was to look at the bone bonding potential of six formulations of a novel glass-ceramic system. Cylinders of the ceramics were implanted in rabbit tibiae for 4 and 7 weeks. Histological tests, both quantitative and qualitative, as well as push-out tests, were carried out during the bonding assessment. Bone growth was quite prolific, even at 4 weeks, as evidenced by growth up to and along the implant surfaces. The interfacial shear strengths compared well with other biomaterials in use as endosseous implants. Therefore it seems pertinent to pursue further long-term experimentation with this material.

Aluminum, Alzheimer's disease and bone fragility

The incidence of fragility fractures has increased epidemically. Especially patients with senile dementia (including Alzheimer's disease) have a greatly increased risk of fragility fractures. Aluminum inhibits bone mineralization; the greater the aluminium exposure, the higher the risk of an early fracture. Aluminium is neurotoxic and may, in addition to genetic factors, play a role in the development of Alzheimer's disease by contributing to the formation of the characteristic beta-amyloid and neurofibrillary tangles. Thus, a common denominator between Alzheimer's disease and bone fragility may be a chronic low-grade aluminum intoxication. The epidemic of fragility fractures may be caused by increased aluminium exposure--due to the use of aluminum cooking pots or the pollution acidification of our environment. In our pilot study of 26 hip-fracture patients (13 patients with Alzheimer's disease and 13 individually age- and gender-matched non-demented patients), the aluminum content, determined mass-spectro-metrically, was higher in trabecular bone biopsies from the patients with Alzheimer's disease than from the non-demented patients (p = 0.005). The aluminum content was also higher in the younger of the 26 patients (p = 0.02). Our findings agree with the hypothesis that aluminum plays a role in the development of Alzheimer's disease and bone fragility.