Urine levels of aluminum after drinking tea

A microwave-assisted acid digestion procedure coupled with a graphite furnace atomic absorption method has been applied in the determination of aluminum (Al) in urine to verify the correlation of free forms of Al in tea infusions and urinary excretion of Al. Significant urinary Al excretion has been found in 24-h urine of four volunteers after tea drinking. However, the difference in amount of Al excretion in urine between the consumption of Oolong (black tea) and Long-Jin (green tea), each of them with unique Al contents and species, was not significant. These findings indicated that the high levels of free Al species in tea infusions did not result in significant change in urinary excretion of the metal, possibly owing to the transformation by ligands present in food and the gastrointestinal tract (GIT). However, it could not be assumed that there was no big difference in absorption of the metal in the human body if fractions of consumed Al retained in the body or excreted by bile or feces were considered.     

Tissue digestion for aluminum determination in experimental animal studies

Four different procedures for the determination of aluminum in tissues by atomic absorption spectrometry (AAS) were investigated. They consisted of conventional acid digestion carried out before and after sample drying, associated or not with fat extraction. Drying was carried out in a conventional oven at 65 °C for 24 h. For fat extraction, different solvents and solvent mixtures were investigated considering both extraction yield and sample adequacy for further AAS measurement. Acid digestion was carried out with pure HNO₃ or with its mixture with HClO₄. After digestion, aluminum was measured by graphite furnace atomic absorption spectrometry. Tissues were collected from Al-exposed and nonexposed mice. The results indicated that drying the sample prior to digestion is advantageous as the amount of acid necessary can be significantly reduced. This procedure does not contribute to increase the aluminum level in the samples providing that careful measures to avoid contamination are taken, as the same procedures carried out without taking any precautions to avoid contamination produced imprecise results. Finally, aluminum was not found in the fatty fraction of any sample, even in exposed mice, demonstrating that aluminum does not accumulate in this part of the tissues.     

Subcellular distribution of aluminum, bismuth, cadmium, chromium, copper, iron, manganese, nickel, and lead in cultivated mushrooms (Agaricus bisporus and Pleurotus ostreatus)

In this work, the distribution of nine metals in two types of cultivated mushroom had been investigated. For Agaricus bisporus, the biomass was separated into caps and stalks, and for Pleurotus ostreatus, the entire mushrooms were taken for analysis. Electrothermal atomic absorption spectrometry was used for total element determination in acid digests. For accuracy checking, the certified reference material (NIST 1571, citrus leaves) was analyzed. The results obtained for the two fungi species were within the ranges of concentration reported previously by other authors. Subcellular fractionation was accomplished by centrifugation of cell homogenates, which has been suspended in Tris-HCl buffer. In the first centrifugation (7300g, 4°C, 10 min), cell walls were separated (pellet I), and the second centrifugation (147,000g, 4°C, 60 min) yielded mixed membrane fraction (pellet II) and cytosol (supernatant II). Recoveries of the fractionation procedure were in the range 70–100% (with the exception of Fe). For all elements studied, the highest relative contributions were found in cytosol fractions of the fruiting bodies (63–72%, 49–76%, 44–93%, 26–87pc, 55–85%, 50–68%, 41–78%, 39–78%, 54–67% respectively for Al, Bi, Cd, Cr, Cu, Fe, Mn, Ni, and Pb. Lower contributions were found in cell walls (respectively 22–32%, 24–44%, 6.1–47%, 12–52%, 7.3–37%, 7.9–32%, 19–52%, 20–42%, and 25–38%) and only minute amounts in the mixed membrane fraction (3.0–5.8%, 0.7–7.0%, 0.7–8.3%, 1.0–22%, 7.5–14%, 16–24%, 1.1–19%, and 5.1–7.7%). The results obtained indicate that small water-soluble molecules were the primary forms of nine elements in two mushroom species studied. On the other hand, the evidence has been provided on elements binding to larger, water-insoluble molecules contained in the structures of cell wall and membranes. The relative distribution was both element and fungi dependent. Thus, in P. ostreatus, total element levels were higher than in A. bisporus, with the preference for their accumulation in cytosol. On the contrary, total element content in the latter fungi was lower; however, a clear tendency toward more efficient element incorporation to the water-insoluble structures was observed (no apparent differences between stalks and caps). These findings might contribute in a better understanding of the accumulation of metals in mushrooms.     

Total chromium in the human lens

A simple, quick procedure has been developed for preparation of human lenses for total chromium (Cr) analysis by electrothermal atomic absorption spectrometry (EAAS). This procedure involves wet ashing in a mini-autoclave with HNO₃ and H₂SO₄. Recovery was 101.6%. This procedure is simple to carry out, does not generate corrosive fumes, and minimizes contaminations. Measurements obtained by this method give values similar to those found previously by more cumbersome methods. It can be conveniently used to prepare biological samples for ultratrace analysis. The mean Cr concentration in human lenses varied between 0.345±0.147 μg/g dry wt in the normal population and 0.205±0.160 μg/g dry wt in cataractous lenses.     

Effect of oral aluminum and aluminum citrate on blood level and short-term tissue distribution of aluminum in the rat

Aluminum (Al) absorption seems to be very low, but many factors can enhance it in animals and humans. In the present study, we investigated the acute effect of Na citrate on Al absorption by monitoring Al levels in blood and several tissues. For this purpose, 18 Wistar male rats were divided into 3 groups: control, Al, and Al + Na citrate. After a 14-h fasting period, animals were dosed orally with deionized water, or 2 mmol Al chloride, or 2 mmol Al chloride plus 2 mmol Na citrate. Blood samples were taken before and 1, 2, 4, and 6 h after the gavage. Al concentrations in blood, liver, tibia, kidney, and intestinal wall were determined by ICP-OES. In the Al and Al + citrate groups, Al blood concentrations peaked at 1 h and 2 h with higher levels in the Al + citrate group. Al gavage resulted in an increase in Al level in intestinal wall, but not in the other investigated tissues. Simultaneous gavage of citrate with Al significantly increased its tissue levels in tibia, kidney, and in intestinal wall. Our data show clearly that Al as chloride can be absorbed, but not well retained by the organism tissues. Furthermore, the model used in the present study is appropriate for acute studies to investigate the effect of various compounds on Al absorption in the rat.     

Simulation of creep in non-homogenous samples of human cortical bone

Characterising the mechanisms causing viscoelastic mechanical properties of human cortical bone, as well as understanding sources of variation, is important in predicting response of the bone to creep and fatigue loads. Any better understanding, when incorporated into simulations including finite element analysis, would assist bioengineers, clinicians and biomedical scientists. In this study, we used an empirically verified model of creep strain accumulation, in a simulation of 10 non-homogeneous samples, which were created from micro-CT scans of human cortical bone of the femur midshaft obtained from a 74-year-old female cadaver. These non-homogeneous samples incorporate the presence of Haversian canals and resorption cavities. The influence of inhomogeneity on the response and variation in the samples in both creep and stress relaxation tests are examined. The relationship between steady-state creep rate, applied loads (stress relaxation and creep tests) and microstructure, that is bone apparent porosity, is obtained. These relations may provide insight into damage accumulation of whole human bones and be relevant to studies on osteoporosis.     

A study of chromium in human cataractous lenses and whole blood of diabetics,senile, and normal population

Chromium (Cr) is of known biological importance, necessary for the maintenance of normal glucose metabolism. There is a lower level of blood Cr concentrations in cases of diabetes. Diabetes carries a risk of cataract development, so the potential effects of Cr on the eye may need to be studied in more depth. The presence of this trace element in both normal and cataractous human lenses has to our knowledge not been investigated so far. The concentration of total Cr in 61 human lenses and 38 blood samples was determined by electrothermal atomic absorption spectrometry with Zeeman effect (EAASZ). Analysis of the levels of Cr in human lenses shows a significant difference between normal and diabetic populations, and an absence of difference between senile and diabetic populations.     

Instrumental neutron activation analysis of rib bone samples and of bone reference materials

The instrumental neutron activation analysis method was used for the determination of trace elements in rib bone samples taken from autopsies of accident victims. The elements Br, Ca, Cl, Cr, Fe, Mg, Mn, Na, P, Sr, Rb, and Zn were determined in cortical tissues by using short and long irradiations with thermal neutron flux of the IEA-R1m nuclear reactor. The reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were also analyzed in order to evaluate the precision and the accuracy of the results. It was verified that lyophilization is the most convenient process for drying bone samples because it does not cause any element losses. Comparisons were made between the results obtained for rib samples and the literature values as well as between the results obtained for different ribs from a single individual and for bones from different individuals.     

Room temperature solvent extraction for simple and fast determination of total concentration of Ca,Cu, Fe,Mg, Mn,and Zn in bee pollen by FAAS along with assessment of the bioaccessible fraction of these elements using in vitro gastrointestinal digestion

Background and aimBee pollen is recognized to be a source of different nutrients, including minerals. As a food supplement, its quality and safety due to concentrations of essential macro- and microelements, and harmful trace elements has to be verified. Fast and simple element analysis of bee-collected pollen can be regarded as an important part of its quality assurance and control. The present study aimed at developping a new method for determination of selected elements (Ca, Cu, Fe, Mg, Mn, Zn) of bee pollen based on solvent extraction and completely avoiding a high temperature treatment with concentrated reagents. In addition, in vitro gastrointestinal digestion was used to assess bioavailability of elements from this food supplement.MethodsBee pollen samples were dried and pulverized. Total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn were determined by flame atomic absorption spectrometry (FAAS) in sample solutions obtained by wet digestion (WD) in concentrated HNO₃ or alternatively by solvent extraction (SE) with diluted solutions of HNO₃. Gastrointestinal digestion was mimicked using simulated solutions of gastric and intestinal juices followed by determination of Ca, Cu, Fe, Mg, Mn and Zn concentrations in the bioaccessible fraction by FAAS.ResultsA new simple and fast method for determination of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen was developed and validated. The method combined room temperature, two-hour SE with 0.5 mol L⁻¹ HNO₃ with FAAS measurements versus simple standard solutions. It provided precision within 1–5 % and trueness better than 8%, and was shown to be suitable for fast analysis of different polyfloral bee pollens. In vitro gastrointestinal digestion revealed that elements were well (70–85 % for Ca, Mg) and fairly (27–43 % for Cu, Fe, Mn, and Zn) bioaccessible from bee pollen. By pouring with water and swelling overnight, bioaccessibility of studied elements from such prepared bee pollen was increased on average by less than 15 % (Mn), 20 % (Ca, Cu, Fe, Zn) or 30 % (Mn).ConclusionsAvoiding long-lasting, high-temperature wet digestion with concentrated reagents, the proposed sample treatment along with FAAS provided precise and true results of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen. The method was simple and fast, and enabled to analyze a higher number of samples. Simulated gastrointestinal digestion of bee pollen have shown for the first time that Ca and Mg are the most bioaccessible from this bee product. Bioaccessibility of Cu, Fe, Mg, and Zn from bee pollen are close to or lower than 40 %.     

On the applicability of bovine morsellized cortico-cancellous bone as a substitute for human morsellized cortico-cancellous bone for in vitro mechanical testing

Morsellized cortico-cancellous bone (MCB) is frequently used in orthopaedic revision surgery to restore lost bone stock. In this study, we examine the validity of using bovine MCB as a substitute for human MCB in in vitro mechanical testing of bone grafts. The paper describes the fat and water content of impacted and unimpacted human and bovine MCB. During this work we applied constrained compression testing to describe the elastic, plastic and time dependent response. Nearly all parameters were found to be significantly different and were influenced differently by impaction for the two types of MCB. The denser trabecular structure, higher fat content of bovine MCB and higher stiffness and compressive strength of cortical bovine bone may explain the differences observed. Consequently we are not confident about the applicability of bovine MCB as a substitute for human MCB for in vitro mechanical testing.     

Age-related changes of bone mineral density in human calcaneus, talus, and scaphoid bone

To examine whether the bone mineral density (BMD) decreases uniformly with aging in any spongy bones, the authors investigated age-related changes of BMD in the calcaneus, talus, and scaphoid bone. After the ordinary dissection by medical students was finished, calcanei, tali, and scaphoid bones were resected from the subjects, and BMDs were measured by dual-energy X-ray absorptiometry. Their BMDs seemed to decrease gradually with aging in the calcanei, tali, and scaphoid bones. It was found that there were statistically significant relationships between age and BMD in the men’s and women’s scaphoid bones, women’s tali, and women’s calcanei, but not in the men’s tali and calcanei. It should be noted that there were significant relationships between age and BMD in both men’s and women’s scaphoid bones. In regard to relationship in BMD between the bones of the upper and lower limbs in individuals, it was found that the relationship between the calcaneus and talus was higher than that between the calcaneus and scaphoid bone. This suggests that there is a higher relationship in BMD between the two tarsal bones compared with that between the tarsal and carpal bones.     

Microwave digestion preparation and ICP determination of boron in human plasma

A microwave digestion procedure, followed by Inductively Coupled Argon Plasma Spectroscopy, is described for the determination of boron (B) in human plasma. The National Institute of Standards and Technology (NIST) currently does not certify the concentration of B in any substance. The NIST citrus leaves 1572 (CL) Standard Reference Material (SRM) and wheat flour 1567a (WF) were chosen to determine the efficacy of digestion. CL and WF values compare favorably to those obtained from an open-vessel, wet digestion followed by ICP, and by neutron activation and mass spectrometric measurements. Plasma samples were oxidized by doubled-distilled ultrapure HNO₃ in 120 mL PFA Teflon^™ vessels. An MDS-81D microwave digestion procedure allows for rapid and relatively precise determination of B in human plasma, while limiting handling hazards and sources of contamination.     

Direct and rapid determination of ultratrace heavy metals in solid plant materials by ET‐AAS ultrasonic‐assisted slurry sampling

Introduction – Plants can be used as bioindicators in the study of contamination processes by heavy metals. Most of the analytical methodologies used for determination of metals in plants are based on atomic techniques with previous wet digestion of the solid samples. Methodologies that allow direct metal measurements in solid samples are very attractive alternatives. Objective – To develop a new procedure for direct analysis of copper, nickel, cadmium and lead at very low concentration levels in leaves based on electrothermal atomic absorption spectroscopy (ET‐AAS) with introduction of samples as a slurry. Methodology – In order to obtain accurate and precise results even at very low concentrations, the different parameters that influence the sample slurry preparation such as acid percentage, presence of stabilising agents and ultrasonic probe operation were studied. Instrumental parameters such as chemical modifier and temperature and times for drying, pyrolysis and atomisation steps that influence ET‐AAS measurement were optimised. Results – Optimal slurry conditions for copper and nickel determination were 0.5% Tween 85 with 5% nitric acid. For lead and cadmium analysis the best results were obtained in 5% nitric acid without stabilising agents. The achieved detection limits were 0.023 mg/kg for copper, 0.018 mg/kg for nickel, 0.0002 mg/kg for cadmium and 0.009 mg/kg for lead. For validation purposes, the method was applied to metal analysis in a pine needles reference material. Conclusion – According to our knowledge, the detection limits obtained are the best reported in the literature. The methodology was successfully used in metal determinations in actual leaf samples. Copyright © 2010 John Wiley & Sons, Ltd.     

The disturbances of the zinc concentration in the blood in selected neoplasms

A study was carried out on 92 patients (58 males and 34 females) aged 42–76 treated for malignant neoplasm of the gastrointestinal tract (54 patients with colorectal carcinoma, 38 with gastric carcinoma). In all patients, the zinc serum concentration was measured and the results obtained were referred to some epidemiological-clinical factors (sex, age, primary cause of cancer, the stage of clinical progression, and histological type). The results showed that the most pronounced hypozincemia occurred in male patients with mucous membrane carcinoma of the stomach.     

Age-dependent aluminum accumulation in the human aorta and cerebral artery

The purpose of this study was to determine the extent of aluminum (Al) accumulation in the human aorta and cerebral arteries. The Al contents in the aortae and in the cerebral arteries from 23 human subjects was determined by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The subjects' age range was 45–99-yr-old; 15 of the subjects were males and 8 were females. Al was detected in twelve aortae and in six cerebral arteries, when the entire specimen was analyzed. Two specimens where Al was found in the cerebral arteries contained no Al in the aorta. No relationship to the subject's sex was found. When related to age, two groups were established. Group L (45–75 yr old) and group H (>75 yr old), which exhibited aortal Al concentrations of 33.3 and 72.7%, respectively. When the aortic wall was dissected into the tunica intima, media, and adventitia, Al was found mainly in the tunica media. In the aorta, significant relationships were found between Al and phosphorus (P) levels (r=0.801,p<0.01) and between Al and calcium (Ca) (r=0.661,p<0.05). We have concluded that Al accumulation is age-dependent and that it occurs both in the aorta and in the cerebral artery. In the aorta, accumulation occurs mainly in the tunica media. Both P and Ca appear to enhance aortal Al accumulation.     

Areal growth in the human fetal parietal bone

The areal growth of the human fetal parietal bone is described using 51 dissected right parietal bones of Japanese fetuses ranging from the fifth month to term. Their shadows were taken on printing paper and analyzed by a sonic digitizer. The absolute growth of the projected area of the fetal parietal bones progresses at a fairly constant rate during the latter half of the fetal period, despite some deceleration in the 9–10th month. By allometric analysis, the allometric coefficients against crown-rump length are 2.201 for males, 2.202 for females, and 2.204 for both sexes, respectively. The allometry is essentially monophasic, showing no inflection point, indicating a change in the slope of the regression line; that is, the growth of the human fetal parietal bone is continuous with a constant specific growth rate. These results are discussed in connection with growth in thickness of the bone.     

Heavy metal concentrations in,and human health risk assessment of,three commercially valuable fish species in the lower Niger River,Nigeria

The concentrations of Fe, Mn, Ni, Pb and V in water, sediment and the gill, liver and muscle tissues of Synodontis resupinatus, Heterotis niloticus and Clarias gariepinus, all commercially important fish species of the lower Niger River, were investigated in 2015. Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l^?1 and 61.60 mg kg^?1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water and Fe > Mn > V > Ni > Pb in the sediments. Metal concentrations were higher in the tissues of S. resupinatus compared with H. niloticus and C. gariepinus. Fe was also highest in the gills, liver and muscle of the three fish species. Its highest concentration of 132.97 mg kg^?1 dry weight was recorded in the gills of S. resupinatus. Bioconcentration factors of metals ranged from 8.79 for Mn in H. niloticus muscle to 67.99 for Ni in S. resupinatus gills. The fish species studied pose no health risk for all metals studied, because the target hazard quotient was less than 1 and the estimated daily intakes of the metals were below the reference doses.     

低氟铝长期与高氟铝短期暴露后大鼠骨生长的比较研究

目的观察不同剂量氟铝联合摄入时间长短对大鼠纵向骨生长及骨代谢的影响。方法48只8周龄体重170~190g清洁级SD大鼠,随机分成正常对照,低氟铝和高氟铝组,且分别设45d和90d组。进行胫骨近端生长板和干骺端松质骨的骨形态计量学分析。结果与正常组比较,高氟铝组生长板增厚,45d组软骨细胞层次清楚,排列整齐,形态无异常,而90d组软骨细胞拥挤,潴留;低氟铝(45d和90d)组干骺端次级小梁骨矿化周长、骨形成率、成骨细胞周长都增加,且骨吸收周长在90d组增加;上述骨代谢指标在高氟铝45d组均增加,90d组均降低。结论高氟铝短期暴露刺激软骨生长,长期抑制纵向骨生长。低氟铝短期暴露只增加次级小梁骨形成,低氟铝长期与高氟铝短期暴露均可刺激小梁骨形成,增加骨吸收,高氟铝长期抑制骨形成和吸收。     

Characterization of Staphylococcus aureus isolates from buffalo, bovine, ovine, and caprine milk samples collected in Rio de Janeiro State, Brazil

Eighty-four staphylococcal isolates were obtained from milk samples from cows, sheep, goats, and buffalo with subclinical mastitis and from colonization samples from ostriches. The animals were hosted in 18 small dairy herds and an ostrich breeding located in 10 municipalities of the state of Rio de Janeiro, Brazil. Thirty isolates were identified as Staphylococcus aureus by biochemical and molecular techniques and were comparatively characterized by phenotypic and genotypic methods. The molecular characterization by pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) revealed five clonal types (PFGE A, spa type t359, sequence type 747 [ST747]; PFGE B, spa type t1180, ST750; PFGE C, spa type t605, ST126; PFGE D, spa type t127, ST751; and PFGE F, spa type t002, ST5). None of the isolates harbored the Panton-Valentine leukocidin or exfoliative toxin D gene. The detection of major clone A (in 63% of the isolates) in different herds, among all animal species studied, and in infection and colonization samples evidenced its geographical spread among Rio de Janeiro State and no host preference among the animal species. Comparison with S. aureus from a human origin suggested that all but one clone found in the present study might be animal specific.     

Chromium content in human milk,Cow's milk,and infant formulas

Chromium was measured by Electrothermal Atomic Absorption Spectrometry in human milk, cow's milk, and infant formulas. The mean levels found were 1.56, 0.83, and 4.84 (13%) μg/L, respectively. According to our data, the daily intake for the Spanish neonates is lower than the Recommended Dietary Allowances (RDAs) (10–40 μg/d) for this element.