Serum Aluminum Concentrations Research Articles

Analysis of serum metal ion levels in dental implant patients

Background: Dental implants have been widely used for the replacement of missing teeth in fully and partially edentulous patients. Titanium (Ti) has been the material of choice for dental implants due to its superior corrosion resistance behaviour and desirable mechanical properties. Hence; the present study was undertaken for assessing the serum metal ion levels in Dental Implant Patients. Materials & methods: A total of 20 subjects with missing mandibular first molar and scheduled for prosthetic rehabilitation for same using dental implant therapy were enrolled. Blood samples were obtained at baseline and sent to laboratory where auto-analyser was used for evaluation of metal ions levels. All the dental implant procedures were carried out under the hands of skilled implantologists. After placement of dental implants, blood samples were obtained at 8 weeks and 6 months follow-up. Metal ions were assessed at subsequent follow-ups. All the results were analysed by SPSS software. Results: Mean serum titanium concentration at baseline, 8 weeks and 6 months was fond to be 2.39 mg/dL, 2.35 mg/dL and 2.38 mg/dL respectively. Mean serum aluminium concentration at baseline, 8 weeks and 6 months was fond to be 4.19 mg/dL, 4.16 mg/dL and 4.18 mg/dL respectively.

Essential elements role in pathogenesis of occupational chronic lumbosacral radiculopathy in coal miners.

The problem of diagnosis in the early and preclinical stages of diseases is important in the prevention of occupational diseases and their complications, because this is the key to the timely initiation of treatment, the implementation of preventive measures. Chronic lumbosacral radiculopathy (CLSR) or low back pain (LBP) is one of the most common diseases in the structure of occupational pathology in Ukraine, which usually develops in those of working professions associated with physical activity, forced work posture, effect of high levels of general vibration, etc. The highest levels of occupational morbidity are recorded in the coal industry, which accounts for about 80% of occupational pathology in Ukraine. Above 1600 cases of CLRS are diagnosed annually in the country. A risk factor for the development of the CLSR is osteoporosis, which arises due to the impairment of quantitative and qualitative characteristics of bone tissue and is characterized by a decrease in its strength, animpairment of microarchitecture with a further increase in risk of fractures. One of the modern methods of assessing condition of bone tissue is determination of the content of macro- and trace elements (MaE and ME) in the biological environments of patients. Ca, Al, Mg, B, P are the most important in the formation and development of bone and connective tissue. To date, studies of bone tissue status in patients with CLSR of professional etiology have not been conducted (small in numbers). Goal – to determine the role of essential elements Ca, Al, Mg, B, P in serum and urine in the formation of occupational CLSR in miners. The research was conducted in 20 miners with CLRS (slaughterer, mining worker of a clearing face (MWCF), drifter) of coal mining industry of Donbass and Lviv-Volyn basins. The results were analyzed in two groups: І group consisted of patients with 10-15 years of work experience (n=10), II group with 16-32 years of work experience (n=10). The control group included 22 patients without pathology of the musculoskeletal system and connective tissue. The inductively coupled plasma atomic emission spectroscopy method (ICPAE) was used to determine the MaE and ME concentrations. The study revealed that the average serum aluminum (Al) concentration in miners with occupational CLSR (115.07 μmol/l) exceeded control group level (3.3 μmol/l) by almost 30 times (p<0.05). Serum boron (B) concentration in both age groups (25.90 μMol/l and 19.43 μMol/l, respectively) were lower than in the control (62.90 μMol/l), (p<0.05). The average serum calcium (Ca) concentration in patients with occupational CLSR (2.82 mmol/l) was 1.3 times higher than the same indicator in the control group (2.16 mmol/l), with a significant difference between the two age groups (p<0.05). It was revealed that the average level of phosphorus (P) in the urine of patients with occupational CLSR (19.0 mmol/l) significantly exceeded its content in patients of control group (11.96 mmol/l) (p<0.05). The concentration of Al in the urine of patients with CLSR in both age groups (1.26 μMol/l and 1.334 μMol/l, respectively) was higher that in control (0.85 μMol/l), (p<0.05). Reduction of Ca and Mg levels in the serum of miners in increasing work experience in harmful working conditions, exceeding average concentration of aluminum in patients' blood compared to the normative value and indicators of the control group patients was established.

Aluminum Toxicity: Evaluation of 16-Year Trend Among 14 919 Patients and 45 480 Results.

- Annual monitoring with serum aluminum measurements is recommended for dialysis patients who are susceptible to toxic accumulation from contaminated dialysis fluid or from ingestion of aluminum-containing medications. - To evaluate long-term trends in serum aluminum concentrations and frequency of chronic toxicity. - A retrospective observational study was conducted by analyzing serum aluminum results obtained from the Veterans Affairs corporate data warehouse. Serum aluminum concentrations of 60 μg/L or greater were considered false positives and not indicative of chronic toxicity if another specimen retested within 45 days had a concentration below 20 μg/L. - A total of 45 480 serum aluminum results involving 14 919 patients and 119 Veteran Affairs facilities during a 16-year period ending in October 2016 were evaluated. The percentage of elevated (≥20 μg/L) serum aluminum results declined from 31.5% in 2000 to 2.0% in 2015. Average testing intervals changed from every 159 days in 2000 to every 238 days in 2015. Of 529 patients with serum aluminum concentrations of 60 μg/L or greater, 216 (40.8%) were retested within 45 days (average = 21 days); of these, 83 (38.4%) had concentrations below 20 μg/L after repeated measurements. Retesting rates increased with higher initial serum aluminum concentrations. - Aluminum toxicity, as assessed by serum levels, has substantially declined over time and is now rare. Many serum aluminum concentrations in the toxic range were not confirmed after retesting. Patients with toxic serum aluminum concentrations should be retested with another specimen before undergoing treatment or investigating sources of exposure to verify abnormal results.

Shift from darbepoetin-α to continuous erythropoietin receptor activator decreases serum aluminium concentration in patients on hemodialysis.

The response of erythropoietic stimulating agents (ESA) in uremic patients may be associated with the changes of biochemical parameters, metal elements and inflammation status during the shift from one ESA to another. We compared changes in above mentioned factors after switching from darbepoetin-α (DPO) 20μg weekly for 10 weeks to continuous erythropoietin receptor activator (CERA) 100μg monthly for 10 weeks in uremic patients on hemodialysis. The haematocrit (Hct), metal elements and inflammation status are the primary outcome. Subjects included 54 patients without transfusion or bleeding or additional ESAs. Responders (IR, n=36) were defined as patients with an increase in Hct after the swtich. Although there was no significant difference in overall mean Hct after the switch (p=0.135), there are significantly greater mean number of red blood cells (RBC) (p=0.006), higher platelet numbers (p=0.001), larger RBCs (p=0.017) and higher creatinine (p=0.04) and total cholesterol (T-CHOL) (p=0.003) levels. Mean overall aluminium (Al) level decreased significantly (p=0.001). C-reactive protein (CRP) also decreased (p=0.016). The overall LDH increased (p=0.049) and potassium decreased significantly (p=0.036), which indicating active erythropoiesis. The calcium (Ca) level was significantly higher (p=0.034) and phosphate was significantly lower (p=0.028) after the shift. Although there was no significant increase in overall levels of parathyroid hormone (PTH) after the shift (p=0.061), but the pre-shift and post-shift PTH level was significantly higher in IRs than in non-IRs (p=0.003 and p=0.027, respectively). IRs had a significantly lower initial T-CHOL (p=0.03) and initial CRP (p=0.012) than non-responders, which may be related to lower inflammation. We found the shift from DPO to CERA results in lower Al levels, a reduced inflammatory response, and an increase in RBC number and PTH level in uremic patients on hemodialysis.

Serum aluminum levels in dialysis patients after sclerotherapy of internal hemorrhoids with aluminum potassium sulfate and tannic acid.

Aluminum potassium sulfate and tannic acid (ALTA) is an effective sclerosing agent for internal hemorrhoids. However, it is contraindicated for patients with chronic renal failure on dialysis, because the aluminum in ALTA can cause aluminum encephalopathy when it is not excreted effectively. We conducted this study to measure the serum aluminum concentrations and observe for symptoms relating to aluminum encephalopathy in dialysis patients after ALTA therapy. Ten dialysis patients underwent ALTA therapy for hemorrhoids. We measured their serum aluminum concentrations and observed them for possible symptoms of aluminum encephalopathy. The total injection volume of ALTA solution was 31 mL (24-37). The median serum aluminum concentration before ALTA therapy was 9 μg/L, which increased to 741, 377, and 103 μg/L, respectively, 1 h, 1 day, and 1 week after ALTA therapy. These levels decreased rapidly, to 33 μg/L by 1 month and 11 μg/L by 3 months after ALTA therapy. No patient suffered symptoms related to aluminum encephalopathy. Although the aluminum concentrations increased temporarily after ALTA therapy, dialysis patients with levels below 150 μg/L by 1 week and thereafter are considered to be at low risk of the development of aluminum encephalopathy.

Chelation of aluminum by combining deferasirox and deferiprone in rats

The hypothesis that two known chelators deferasirox and deferiprone (L1) might be more efficient as combined treatment than as single therapies in removing aluminum from the body was tested in a new acute rat model. Seven-week-old male Wistar rats received chelators: deferasirox (orally [p.o.]), L1 (p.o.) or deferasirox + L1 as 100 or 200 mg/kg dose half an hour after a single intraperitoneal administration of 6 mg Al/kg body weight in the form of chloride. Serum aluminum concentration, urinary aluminum and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level. While deferasirox was more effective than L1 in enhancing urinary aluminum excretion, L1 was more effective than deferasirox in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the L1 effect on aluminum and L1 did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of aluminum chelators. Urinary values were more useful due to the high variability of serum results.

SOME BIOLOGICAL RISKS IN RATS AS A RESULT OF COOKING IN ALUMINUM UTENSILS

The effects of cooking and / or storage for 7 days of fresh green peas using aluminum kitchen utensils at three different pH values with or without adding sodium chloride in comparison with stainless steel utensils were examined. Biological demonstration in rats revealed the effects of consuming aluminum contaminated diet on hematological measurements RBC’s, WBC’s, platelets counts and erythrocyte indices. Further more the biochemical changes in blood hemoglobin, hematocrit, and the levels of serum iron, calcium and aluminum, as well as the oxidative stress status and tibia characteristics were also investigated. The results showed that using aluminum utensils at acidic medium significantly increased aluminum concentrations in cooked and / or stored peas samples by about 11.5% and 18.7% , respectively, while adding NaCl dose,.3g/20g peas resulted in progressive increment reaching 14.45% and 26.9% respectively. The levels of aluminum were also elevated markedly in the stored samples with or without adding NaCl in both neutral and alkaline medium, while it’s increment ranged between 4 to 5% in cooked samples in case of adding NaCl or not. Aluminum accumulation decreased hematological measurements due to its toxic effects. The decrease of hemoglobin and hematocrit reached 30.0% and 8.36%, respectively, accompanied by decreasing the levels of iron and calcium in serum by about 6.35% and 18.3%, respectively. In contrast, there was 21% elevation in serum aluminum concentration which significantly lowered the antioxidant mechanisms as shown in plasma level of malondialdehyde (5.76 ± 0.24 nmol/ml) as compared to (1.64 ± 0.10 nmol/ml) associated with decreased level of erythrocytes super oxide dismutase by about 19.4%.Tibia characteristics showed a significant increase in weight and density as aluminum accumulation with calcium demineralization at the end of the experiment (12 week). It could be concluded that aluminum leaching from aluminum utensils, especially during storage of acidic foods, in hematological measurements and its physiological function roles also, will cause undesirable changes in oxidative stress and bone dysfunction.

Aluminum concentration in serum of children on long-term parenteral nutrition and in parenteral nutrition solution components

summary Background & Aims: Aluminum is a contaminant of parenteral nutrition solutions. Children who receive long-term parenteral nutrition are at risk of aluminum overload in tissues and its toxic effect. The aim of this study was to assess the incidence of aluminum overloading in those children and the level of aluminum contamination in parenteral nutrition solutions. Methods: A furnace atomic absorption was used to assess serum aluminum concentration in 24 patients, aged 2–20 years. These patients had received parenteral nutrition therapy ranging from 2 years to 14.7 years. Aluminum concentrations were also determined in parenteral nutrition solution components. Results: We found increased amount of aluminum concentration in calcium gluconate (6000 mg/l), in trace element (Addamel :7 00mg/l), amino acid solution (10% Primene :6 0mg/l), lipid-soluble vitamins (Vitalipid :5 00mg/l), and lipids emulsions (20%ClinOleic :1 10mg/l, Lipofundin MCT/LCT :5 5mg/l). Aluminum intake from parenteral nutrition was 5.81–29.64 mg/kg/day, a dose exceeding the safety limit of 5 mg/kg/day. We found increased aluminum concentration (>20 mg/l) in serum of 10 patients; 7

Aluminum accumulation in critically ill children on sucralfate therapy.

BACKGROUND: Sucralfate, used in stress ulcer prophylaxis, contains aluminum, which can be absorbed from the gut. OBJECTIVE: To determine whether toxic serum aluminum levels can develop after short-term sucralfate therapy in critically ill children. DESIGN: Retrospective clinical study. SETTING: Pediatric intensive care unit of a pediatric university hospital. PATIENTS: Nineteen patients receiving mechanical ventilatory support (median age, 5 yrs [range, 0.25-16 yrs]; median weight, 17 kg [range, 3.5-60 kg]). INTERVENTIONS: All patients received sucralfate suspension nasogastrically. Measurements and RESULTS: Serum aluminum concentrations were measured after a short period on sucralfate therapy (median time, 7 days [range, 3-14 days]). There was no correlation between total sucralfate dose received (p =.35) or dose of sucralfate per unit of body weight (p =.55) and serum aluminum. Nine patients received peritoneal dialysis. Serum aluminum levels were higher in the nine patients who received peritoneal dialysis (median aluminum concentration, 2.86 &mgr;mol/L [range, 0.19-12.3 &mgr;mol/L]) than the ten patients not dialyzed (median aluminum concentration, 0.55 &mgr;mol/L [range, 0.18-0.94 &mgr;mol/L]) (p =.001). The peak serum creatinine levels were higher in the dialyzed patients (median creatinine level, 500 &mgr;mol/L [range, 163-910 &mgr;mol/L]) than those not dialyzed (median creatinine level, 98 &mgr;mol/L [range, 36-415 &mgr;mol/L]) (p =.006). There was a trend toward correlation between peak serum creatinine and serum aluminum (p =.06). CONCLUSION: Aluminum accumulation occurs in children with acute renal failure on sucralfate, especially those receiving dialysis. If sucralfate is used in children in renal failure, serum aluminum concentrations should be monitored regularly.

Chelation of aluminium by combining DFO and L1 in rats

The hypothesis that two known chelators 1,2-dimethyl-3-hydroxypyrid-4-one (L1) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing aluminium from the body was tested in a new acute rat model. Five-week old female rats received chelators: L1 (p.o.), DFO (i.p.) or L1+DFO as 100 or 200 mg/kg dose half an hour after a single i.p. administration of 6 mg Al/kg body weight in the form of chloride. Serum aluminium concentration and urinary aluminium and iron excretions were determined by electrothermal or flame atomic absorption spectrometry. Both chelators were effective only at the higher dose level. While DFO was more effective than L1 in enhancing urinary aluminium excretion, L1 was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group L1 did not increase the DFO effect on aluminium and DFO did not increase the effect of L1 on iron elimination. However, in this group a simultaneous increase in both aluminium and iron elimination was observed. Our results support the usefulness of this animal model for preliminary in vivo testing of aluminium chelators. Urinary values were more useful because of the high variability of serum results. Result of combined chelators treatment should be confirmed in a different experimental model before extrapolation to other systems. This testing procedure of course does not provide all the relevant answers for evaluating the efficiency of chelating agents in aluminium toxicity.

Biochemical and hematological changes in low-level aluminum intoxication.

The aim of this study was to investigate the biochemical and hematological changes in patients on routine hemodialysis treatment when they were accidentally exposed to moderately high serum aluminum concentrations during a period of time of less than four months. We studied the changes in biochemical and hematological measurements in 33 patients on dialysis in our hospital before and during the exposure to about 0.85 pmol/l of aluminum in dialysis water due to a malfunction of the reverse osmosis system of water purification. Patients showed a decrease in the hemoglobin concentration from 115+/-12.4 g/l to 108+/-12.2 g/l (p=0.026) and in the mean corpuscular hemoglobin concentration from 5.15+/-0.22 to 5.02+/-0.30 mmol/l (p=0.014). Ferritin was decreased from 243+/-192 microg/l to 196+/-163 microg/l (p=0.047) and transferrin saturation from 0.20+/-0.06 to 0.15+/-0.07 (p=0.004). Biochemical measurements related to calcium-phosphate metabolism did not change. Otherwise, all patients showed an increase in serum aluminum from 0.56+/-0.44 to 1.63+/-0.52 micromol/l (p<0.001). No differences were detected in serum aluminum between patients receiving and not receiving oral aluminum salts. Even moderately high aluminum concentrations maintained during a short period of time could produce significant hematological alterations and a depletion of body iron stores before clinical manifestations were evident.

Environmental Infection and Heavy Metal Analysis in More Than 400 Patients. Part I: Metal Analysis of Aluminium, Lead, Selenium, Zinc

Purpose: Chronic diseases can develop through metabolic disturbances in trace elements and vitamins, and be maintained by environmental toxins. In order to gain more insight into these complex interactions and evaluate therapeutic regimens, we collected and analysed blood and urine from patients. Design: Laboratory- and clinical-based survey. Materials and Methods: Serum samples were obtained at the beginning of and during therapy from 489 patients (17-86 years; 308 males, 181 females; >75% outpatient care, 1995-1997). Besides routine blood analyses, blood concentrations of trace elements, vitamins and environmental toxins were evaluated. The medical histories, analysis of metal ion serum concentrations (e.g. aluminium, mercury, lead, selenium, zinc) and urine analyses of metal excretions are reported and correlated. Results: Serum aluminium concentrations were below 20 μg L -1 in only 17% of initial analysis. Serum lead concentrations were below 20 μg L−1 in only 1.6% and between 20-50 μg L−1 in only 52.1%. Serum selenium concentrations were above 100 μg L−1 in only 14.5%. Serum zinc concentrations were below 70 μg L−1 in 4.7%. Serial determinations during various diseases are reported, e.g. lymphoma, cirrhosis of the liver, pancreatitis, Crohn's disease, ulcerative colitis, tumours and neurological disorders. The medical history and biochemical findings, including heavy metal excretions of a patient with neurological complaints related to dental amalgam, are reported. Conclusions: The results of the long-term observations suggest that serial determinations, e.g. of trace elements and environmental toxins, are essential because of the observed fluctuating serum concentrations. This is especially necessary in the pathophysiological evaluations and analyses of chronic disease development. Furthermore, serial determinations are necessary in order to adapt the appropriate therapeutic interventions and the doses of trace element therapy.

Silicon and aluminium interactions in haemodialysis patients.

Aluminium toxicity in dialysis patients is well described. Aluminium has a close chemical affinity with silicon. Silicon may have a role in protection against aluminium toxicity. We measured serum aluminium and silicon levels from haemodialysis patients from four different centres. Though no relationship was seen across all centres combined, in one centre there was a reciprocal relationship in patients on home haemodialysis (who did not require reverse osmosis). Median (range) aluminium levels were higher, 2.2 (0.4-9.6) micromol/l when serum silicon was less than 150 micromol/l, and lower, 1.1 (0.2-2.8) micromol/l when serum silicon levels were greater than 150 micromol/l (P = 0.03). In patients treated by haemodialysis without reverse osmosis high serum silicon concentrations were associated with lower serum aluminium concentrations than those with low serum silicon. Further work needs to confirm a preventative role for silicon in the accumulation and subsequent toxicity of aluminium in dialysis patients.

Histomorphometric analysis of aplastic bone disease in chronic renal failure at initiation of haemodialysis: Relation to aluminum and parathormone

SUMMARY: We studied bone histology of 134 uraemic patients without a history of vitamin D administration at the start of haemodialysis. Patients were categorized according to bone histology as follows: aplastic bone disease (ABD), ostitis fibrosa, mixed type, mild hyperparathyroidism and osteomalacia. On initiation of haemodialysis, ABD was observed in 48.5% of patients. the average age of the ABD group (50.8 ± 12.5 years) was significantly higher than that of patients with other histologies (P&lt;0.01). Serum parathyroid hormone (PTH) and alkaline phosphatase (ALP) concentrations were lower (P&lt;0.01) in the ABD group, especially in patients with diabetes mellitus. Patients with diabetes mellitus and ABD had lower serum concentrations of PTH and ALP than non‐diabetic patients, suggesting that depressed PTH may be related to ABD. Eleven (55%) of the 20 patients who were receiving A1(OH)3 also had ABD. A direct relationship was observed between serum aluminum concentration and aluminum‐positive bone surface (r=0.60; P&lt;0.01). Aluminum staining was more frequently observed in the ABD group than in the non‐ABD group (P&lt;0.01). Because serum intact‐PTH concentrations correlate with osteoid surface area, fibrosis volume and bone formation rate, it may be a useful marker of bone histology in renal osteodystrophy. These results suggest that, in addition to conservative treatment with A1(OH)3, other factors may be involved in the formation of ABD which is often present at the start of haemodialysis.

Low percentage of aluminoxamine and ferrioxamine in uremic serum after desferrioxamine administration

HPLC was used to study the effectiveness of two different desferrioxamine (DFO) administration strategies (15 mg/kg DFO, 1 h or 44 h before dialysis) on generation of aluminoxamine and ferrioxamine in five hemodialysis patients. The percentage of ultrafilterable aluminum and iron in these patients was also investigated by electrothermal atomic absorption spectrometry. The administration of DFO in both schemes increased the ultrafilterable serum aluminum concentrations from a mean of 17.1 +/- 1.6% to a mean of 75.7 +/- 14.1%. However, 1 h after DFO infusion, only 38.8 +/- 7.7% of the total serum aluminum was bound to DFO; 44 h after DFO infusion, only 15.8 +/- 8.0% was bound. Similar results were obtained for ferrioxamine. These results suggest that the ultrafilterable serum fraction contains aluminum and iron chelated by DFO and by DFO metabolites, which retain similar metal-chelating abilities.

Time course and functional correlates of post-transplant aluminium elimination.

Urinary excretion of aluminium after a successful transplant can reverse pre-transplant aluminium intoxication. We have evaluated the time course of urinary aluminium excretion and its correlation with several parameters of renal function and mineral metabolism in 49 patients (33 men and 16 women) with a wide range of pre-transplant serum aluminium concentrations, performing sequential determinations at pre-transplant time and at 7, 30, 60, and 90 post-transplant days. Mean serum aluminium at pre-transplant was 54.5+/-46.8 microg/l decreasing progressively to 28.7+/-24.4 microg/l at 90 days (P<0.0002), paralleling the decrease in serum creatinine. Urinary aluminium decreased from 63.0+/-77.9 to 52.4+/-55.9 microg/l at 90 days (P<0.0001). The maximum urinary aluminium/creatinine was 1.8+/-2.7 at 7 days and was associated with the greatest fractional excretion of sodium (4.7+/-5.1%), and the lowest tubular reabsorption of phosphate (55.7+/-25.1%). The fractional excretion of aluminium was also greatest at day 7 (1.1+/-0.9%) when serum creatinine was still elevated (3.6+/-2.3 mg/dl). At each period of time after transplantation fractional excretion of aluminium was similar in all patients despite disparate serum aluminium concentrations. Fractional excretion of aluminium was highest in those patients who developed post-Tx acute tubular necrosis (0.7+/-0.5 vs 1.5+/-1.0%, P=0.008). We found a direct positive correlation (r=0.43; P<0.002) between urinary aluminium and urinary phosphate. Basal levels and sequential changes in serum PTH, calcium, and phosphate did not correlated with fractional excretion of aluminium. These findings suggest: (i) urinary aluminium remains elevated during prolonged periods after transplant and is probably a marker of pre-transplant tissue aluminium accumulation; (ii) post-transplant fractional excretion of aluminium seems to correlated positively with other evidences of renal tubular dysfunction. Early post-transplant tubular malfunction could significantly enhance urinary aluminium elimination.

Kinetics of aluminum disposition after ingestion of low to moderate pharmacological doses of aluminum.

We assessed the kinetics of aluminum uptake and elimination by tissues of Sprague–Dawley rats following a single gavage dose of 0, 0.25, 0.5, or 1 mmol Al/kg body weight (b.w.) in 1 ml of 16% citrate (equivalent to 0–650 mg Al to a 70-kg human). Serum, liver, kidney, and tibia aluminum concentrations were measured 15, 30, 60, 120, 270, and 360 min after dosing. Serum aluminum concentrations were proportional to dose in rats dosed with 0.25 or 0.5 mmol Al/kg b.w. but were not proportional to dose for rats dosed with 1 mmol Al/kg b.w. Elimination half-lives of serum aluminum were similar for all treatments (102–119 min) which suggests that the non-linear aluminum kinetics in serum reflected a difference in absorption of the highest dose. Although fasted rats dosed with 0.25 or 1 mmol Al/kg b.w. with citrate absorbed aluminum with similar efficiency (4.2% of dose), the length of the absorptive period was prolonged in the rats given the highest does. Total absorbed aluminum mass in rats dosed with 0.25 and 0.5 mmol vs. 1 mmol Al/kg b.w. reached a plateau at 120 vs. 270 min after dosing, respectively. The kinetics of aluminum in liver, bone, and kidney were generally dose-independent. Elimination half-lives of liver aluminum were similar for all aluminum treatments (267–465 min); elimination half-lives could not be estimated in bone and kidney because of turnover exceeded the 6 h collection period.

Aluminum exposure and excretion

Occupational exposure to aluminum can be associated with increases in both urinary aluminum excretion and serum aluminum. In most studies, the increases in urinary aluminum are proportionately greater than the changes in serum aluminum. A similar pattern of response follows increases in dietary aluminum intake. Thus, there is ample evidence for systemic aluminum absorption from occupational exposure to airborne aluminum as well as dietary intake. Although both circumstances are accompanied by a similar renal response, there is little information explaining how normal kidneys augment renal excretion with only trivial changes in serum aluminum concentrations. In addition, it is not understood how airborne exposure to microgram amounts of aluminum produces significant increases in urinary aluminum. The latter observation suggests the presence of a sensitive uptake process for aluminum from airway exposure.

Parenteral aluminum loading in critical care medicine. Part II: Response to aluminum load from long-term parenteral nutrition.

Evaluation of the iatrogenic aluminum load by aluminum-contaminated nutritive infusion solutions in long-term total parenteral nutrition (TPN). 16 consecutive patients (6 children, 10 adults) who had to undergo total parenteral nutrition for more than one month. Three of them were from a home parenteral nutrition program. The duration of TPN was up to 68 months. The parenteral aluminum load was calculated on the basis of the individual TPN programs. Six patients were exposed to an additional parenteral aluminum load in the course of intensive care. Comparative group: To establish a reference range, the serum aluminum concentrations were determined in 71 unloaded patients who had to undergo minor surgical procedures. ALUMINUM ANALYSIS: Strict adherence to a contamination-free sampling and processing technique. The aluminum determination was performed at the Hahn-Meitner-Institute Berlin by means of graphite-furnace atomic absorption spectrometry (GFAAS). The TPN-associated daily aluminum load was 3.5 +/- 0.4 micrograms/kg body weight (bw) in children and 2.2 +/- 1.8 micrograms/kg bw in adults. 59 +/- 6% of the intravenous aluminum load in children and 42 +/- 16% in adults was due to the highly contaminated small-volume calcium, inorganic phosphate, trace element and vitamin parenterals. The median serum aluminum concentration under TPN was 10.9 micrograms/l (range: 5.0-26.9 micrograms/l) and was thus 7.3 times higher than in the preoperative control group (median: 1.5 micrograms/l, 95% confidence interval: < 0.6-3.5 micrograms/l). Individual values ranged up to 36.8 micrograms/l. The aluminum intake of patients on parenteral nutrition in Germany is thus on occasion considerably above the ASCN/ASPEN recommendations for the limitation of intravenous aluminum loading (ASCN: American Society for Clinical Nutrition; ASPEN: American Society for Parenteral and Enteral Nutrition). The toxicological significance of parenteral aluminum loading is discussed. The results suggest that limits should be established for the Aluminum contamination of infusion solutions.

Effect of citrate on serum aluminum concentrations in hemodialysis patients: a prospective study.

Twenty hemodialysis patients were prospectively evaluated to determine if concomitant citrate and aluminum administration enhances the absorption of aluminum, thereby increasing the possibility of toxicity. The four-phase study consisted of phase I, a washout phase; phase II, an aluminum treatment phase; phase III, a treatment phase combining aluminum and soluble calcium citrate; and phase IV, a treatment phase with the patient's original prestudy phosphate binder. Results disclosed a progressive rise in serum aluminum levels (microgram/L) from 47 +/- 8 (phase I) to 62 +/- 12 (phase II) to 74 +/- 13 (phase III) and a drop to 58 +/- 12 (phase IV). The difference in levels between phases I and III was significant. Additionally, and despite the fact that serum calcium concentrations did not change, serum phosphate and immunoreactive parathyroid hormone concentrations were significantly lower when aluminum and citrate were used together. This suggests that citrate enhances the absorption of aluminum and therefore increases the possibility of toxicity in the patient with end-stage renal disease.