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J B Cannata

Publications and source records attributed to J B Cannata.

At least 37 records · Page 2Linked to original sources
PubMed1996

Staining of bone aluminium: comparison between aluminon and solochrome azurine and their correlation with bone aluminium content.

The aim of this study was to compare the sensitivity and specificity of the two histochemical stains most commonly used as indirect markers of the aluminium bone content. The clinical study was made in 28 biopsies from patients undergoing haemodialysis and the experimental study in 17 tibias from Wistar rats aluminium overloaded and with different deposits of iron. All samples were stained with aluminon, solochrome azurine and Perls and aluminium bone content was also measured. When the positive cases with Perls were excluded in the clinical study (without iron interference), the trabecular surface stained with solochrome azurine correlated with the aluminium bone content (r = 0.71, P < 0.001). With aluminon, on the other hand, no correlation was found. Solochrome azurine was always positive with aluminium contents greater than 8 micrograms/g. Aluminon was positive over 17 micrograms/g. In the experimental study, the iron concentration, in addition to other parameters, was also measured. As in the clinical study, the trabecular surface stained with solochrome azurine correlated with the aluminium content. If the positive Perls cases were excluded, the trabecular surface stained with solochrome azurine doubled the trabecular surface stained with aluminon (P < 0.001). No intratrabecular aluminon staining was observed while the intratrabecular solochrome staining correlated with the aluminium content (P < 0.001). Solochrome azurine was more sensitive than the aluminon and its lack of specificity can be easily corrected by employing Perls staining to exclude the iron interference.

Aluminum↗
PubMed1996

Influence of iron status in the response to the deferoxamine test.

The study presented here was carried out to evaluate the possible relationship between serum iron and iron transferrin saturation with the response to the deferoxamine test in 86 chronic renal failure patients undergoing hemodialysis. The deferoxamine test was performed as a diagnostic tool for aluminum intoxication. Basal serum aluminum levels correlated with: (1) serum aluminum levels after the infusion of deferoxamine (r = 0.45; P < 0.05); (2) serum iron levels (r = -0.26; P < 0.05), and; (3) iron transferrin saturation (r = -0.33; P < 0.05). The increase in serum aluminum levels after deferoxamine administration (DAI) showed a negative relationship with serum iron levels (r = -0.23; P < 0.05) and iron transferrin saturation (r = -0.26; P < 0.05). The correlations improved when analysis of this study included only those patients with high serum iron levels or high iron transferrin saturation (r = -0.55). Patients with low probability of having aluminum overload (serum iron levels < 40 micrograms/L and DAI < 150 micrograms/L) had significantly higher values of serum iron, iron transferrin saturation, and serum ferritin levels compared with those patients with a high probability of having aluminum overload (serum aluminum levels > 40 micrograms/L and DAI > 150 micrograms/L). The study presented here suggests that patients who have indicators of iron repletion would tend to have lower increases in serum aluminum levels after the challenge with deferoxamine and presumably a higher incidence of false negative results with the deferoxamine test. These findings indicate that iron measurements must be always taken into account when interpreting the deferoxamine test.

Aluminum↗
PubMed1995

Mechanisms of aluminum-induced microcytosis: lessons from accidental aluminum intoxication.

Twenty-three hemodialysis patients exposed to an accidental aluminum overload, showed increased erythropoietin requirements and decreased erythrocyte mean corpuscular volume (MCV). At the peak of the intoxication, MCV and plasma aluminum levels changed from unrelated (r = 0.02) to strongly related (r = 0.425) variables. The molar proportion of plasma aluminum to plasma iron increased dramatically (from 1:13.8 to 1:2.4). This significant increment in the aluminum/iron ratio made higher the relative offer of aluminum with respect to iron to the erythroid precursor cells. Accordingly, in a subset of 13 randomly selected aluminum-intoxicated patients we found increased intraerythrocytic aluminum, which paralleled the increase in plasma aluminum. Furthermore, in the aluminum-intoxicated group, intraerythrocytic ferritin, a marker of iron content, and the ratio between erythrocyte and plasma ferritin were lower (P < 0.01 and < 0.001, respectively), than in the control group. These findings support the hypothesis that in some cases of aluminum-related microcytosis, a ferropenic mycrocitosis, as expression of erythroid ferropenia, may exist in spite of the presence of normal body iron stores.

Aluminum↗
PubMed1994

Reproducibility of a questionnaire on risk factors for osteoporosis in a multicentre prevalence survey: the European Vertebral Osteoporosis Study.

BACKGROUND: The European Vertebral Osteoporosis Study Group (EVOS) developed a questionnaire, back translated into 14 different European languages, for use in a multinational epidemiological study of vertebral osteoporosis. We investigated the reproducibility of this questionnaire in four of the participating study centres. METHODS: In all 151 men and women, aged 50-85 years, from Lubeck (Germany), Malmo (Sweden), Warsaw (Poland) and Oviedo (Northern Spain), were retested with the questionnaire on two occasions using a different observer within a 28-day period. RESULTS: Questions relating to personal or medical history were more reproducible than questions concerning subjective symptoms or aspects of lifestyle. The level of agreement for the non-ordinal categorical variables, as estimated by kappa, varied from 0.38 to 1.00 across the four centres. Agreement for the multicategory ordinal, mainly lifestyle, questions was in general poorer though improved when a weighted analysis was performed. For continuous data the 95% limits of agreement were narrow, and there was no evidence of bias between interviewers. There were no important differences in reproducibility across the four centres for either categorical or continuous data. CONCLUSION: The study indicates that the questionnaire may produce useful and comparable information concerning risk factors for osteoporosis across different countries and in different languages. It also highlights that questionnaire instruments designed for use in multinational population-based studies may provide data of comparable quality across a range of settings.

Aged↗
PubMed1993

Serum aluminum transport and aluminum uptake in chronic renal failure: role of iron and aluminum metabolism.

Several factors have been blamed for increasing gastrointestinal absorption of aluminum. The likely role of iron metabolism was suggested some years ago. As iron and aluminum share many chemical properties, it is reasonable to think they also share biological pathways. The aim of this study was: (a) to evaluate serum aluminum transport and its relationship with iron-binding capacity, and (b) to investigate aluminum hydroxide absorption as a function of iron and aluminum. We investigated 127 patients with chronic renal failure undergoing hemodialysis in a study divided into two phases: phase 1, a basal study to investigate serum iron and aluminum status, and phase 2 in which an aluminum absorption test was performed. In phase 1, we found that the lower basal serum iron and iron transferrin saturation the greater serum aluminum (p < 0.001). In phase 2, we found a negative relationship between serum aluminum increments after the test and basal levels of serum aluminum and iron (r = -0.70; p < 0.001). These results suggest that the amount of either aluminum or iron carried by transferrin may influence the transferrin capacity to bind the other element and also may modulate, together with other factors, the gastrointestinal absorption of iron and aluminum.

Aluminum↗
PubMed1993

[Chronic renal insufficiency and secondary hyperparathyroidism in rats. Biochemical and histological evaluation].

Chronic renal failure (CRF) in rats (surgical nephrectomy, 5/6) as well as its derived bone lesions have been studied. Eighty-five male Wistar rats were used, to which chronic renal failure was induced in 1 or 2 surgical times, the parameters of renal function in basal conditions and at different times after surgery being determined. With the method used chronic renal failure is induced with values of creatinine clearance 2/3 times lower than the initial ones (p < 0.05), which stabilize at the 7th week. On the other hand the parathyroid hormone levels (PTH) in serum triple (from 125 +/- 49 to 395 +/- 191, p < 0.05), and a decrease in the tubular phosphate reabsorption is produced (p < 0.001). In bone histology an increase in resorption and bone formation is observed as well as paratrabecular fibrosis, all of which is compatible with the histological diagnosis of hyperparathyroidism. The model of surgical renal insufficiency with ablation of 5/6 of the renal mass, reduces renal function to 1/3 of the initial values after 7 weeks, this procedure having a 20% global mortality without differences being observed between the carrying out of nephrectomies in 1 or 2 surgical times. This degree of CRF was accompanied by secondary hyperparathyroidism both at the biochemical and histological levels, findings which are of great usefulness for future experimental studies.

Animals↗
PubMed1991

Role of iron metabolism in absorption and cellular uptake of aluminum.

The effect of iron status on aluminum (Al) absorption was investigated in this study in vivo using an animal model and in vitro using an intestinal mucosal cell line. In the in vivo model rats were rendered iron overloaded by intraperitoneal injection of iron dextran (5 mg/48 hr) or iron deficient by phlebotomy (2.5 to 3 ml blood/week). These rats, and normal controls, were then dosed with Al(OH)3 (40 mg/day) for 30 days. Urinary excretion of Al was significantly greater in the iron deficient group than in the other two groups throughout the study period, and brain Al at the end of the experiment was significantly increased in the iron depleted group (1.93 micrograms/g) and decreased in the iron overloaded group (0.73 microgram/g) compared with controls (1.42 micrograms/g). The brain Al levels in iron overloaded rats were no higher than those in normal rats that had not been dosed with Al(OH)3 (0.61 microgram/g). No significant differences were found in serum Al levels. In the in vitro experiments cultures of the rat intestinal cell line RIE1 were iron overloaded by addition of iron nitrilotriacetate (0.1 mM) or iron depleted with desferrioxamine (5 micrograms/ml) for 20 days prior to pulsing with Al transferrin (0.5 mg/ml) for 24 hours. Uptake of Al was significantly greater in the iron depleted cells (2.3 ng/micrograms cell DNA) than in iron overloaded (0.81 ng) or untreated (0.83 microgram) cells. These studies show that iron depletion markedly increases absorption and cellular uptake and suggest that susceptible individuals, such as renal failure patients, run an increased risk of toxicity if they are iron deficient.

Aluminum↗
PubMed1991

Iron uptake in aluminium overload: in vivo and in vitro studies.

In this study we have evaluated the haematological consequences of chronic aluminium (Al) overload. We have also investigated 'in vivo' whether aluminium overload may modulate gastrointestinal iron (Fe) absorption and 'in vitro' whether the presence of aluminium may influence the cellular uptake of iron. The in vivo studies were performed in rats with normal renal function and the in vitro experiments were done using the rat intestinal epithelial cell line RIE-1. The results demonstrate that aluminium deposit in tissues even with normal renal function. The intraperitoneal aluminium loading resulted in serum and tissue aluminium increases comparable with concentrations found in aluminium-intoxicated renal patients. The aluminium intoxication was accompanied by a microcytic anaemia with a haematological pattern similar to that observed in iron-deficiency anaemia. Nevertheless, iron absorption was significantly reduced despite an increased total iron binding capacity (TIBC). In addition, aluminium was also able to reduce in vitro cellular uptake of iron in the RIE-1 intestinal cell line. These experimental results demonstrate that aluminium interferes with iron absorption and iron transfer, and suggest that these mechanisms may be responsible for maintaining and even increasing the anaemia observed in aluminium overload.

Aluminum↗
PubMed1991

Aluminium uptake by intestinal cells: effect of iron status and precomplexation.

The investigation of different aluminium-binding agents and metabolic conditions that might act as critical factors in modulating aluminium absorption could yield valuable information in the understanding of aluminium gastrointestinal absorption. We evaluated the effect of iron depletion in aluminium uptake and the role of transferrin and citrate in aluminium incorporation by the intestinal epithelial cell line RIE1. Both complex, aluminium-citrate and aluminium-transferrin were prepared in a molar ratio of 2:1; both facilitated the aluminium uptake although a greater aluminium incorporation was found when aluminium was administered as aluminium-transferrin. This difference became even greater in the iron-depleted cells (normal cells vs iron-depleted cells): 7.7 +/- 1.4 versus 30 +/- 5.6 ng Al/micrograms DNA (P less than 0.05). From these and previous data it is possible to speculate that iron status could modulate the intestinal uptake of aluminium and that both transferrin and citrate would act as effective carriers in the incorporation of aluminium into mucosal cells.

Aluminum↗
PubMed1990

High performance liquid chromatography methods for studying protein binding of aluminium in human serum in the absence and in the presence of desferrioxamine.

Ion-exchange high performance liquid chromatography of serum proteins was combined with aluminium determination by electrothermal-atomisation-atomic-absorption spectroscopy and fluorimetry for studying the distribution of aluminium in human serum in the absence and in the presence of desferrioxamine. Aluminium was eluted as a single peak in the same fraction as transferrin. However, following the addition of desferrioxamine most of the aluminium was liberated from transferrin and become attached to the chelator.

Aluminum↗
PubMed1989

[Serum aluminum and normal kidney function: effect of age and environmental exposure to aluminum].

The first cases of aluminium (Al) toxicity were reported in metal workers with apparent normal renal function. Although safety in industry has had a great improvement over the last decades, it is reasonable to think that Al workers might have a higher daily Al exposure than normal population. Therefore the aim of this study was to investigate the serum Al levels in volunteers with normal renal function, having different jobs, including people working in the main Al factory in our area. There were no significant differences in serum Al values among people working in the Al factory or in other jobs, likewise there were no differences regarding: sex, alcohol consumption, smoking habits, etc. By contrast, as we expected, urinary Al excretion was higher (p less than 0.005) in Al workers. There was a significant serum Al increase proportional to the increase of age (p less than 0.01). The known decline of renal function observed with the increasing of age and therefore the likely decrease in Al clearance, could be responsible for the serum Al increase.

Adult↗
PubMed1989

[Hyperaluminemia and parathormone release].

Previous studies have shown that aluminum (Al) could inhibit parathyroid function. However, controversy still remains about the possible mechanisms implicated. Thus, the aim of this study was to evaluate the acute parathyroid hormone (PTH) response to intravenous Al infusion. Male Wistar rats were divided into two groups: Group A (n = 5): received 0.1 ml of saline. Group B (n = 5): received 0.5 mg of Cl3Al in 0.1 ml of saline. In both groups ionized calcium (Ca(+)+) decreased, but despite a similar degree of haemodilution, this change was only significant in group A. This variable Ca(+)+ decrease was followed by different responses in the PTH secretion. In group B there was a significantly (p less than 0.05) lower PTH release compared with control group. These results suggest that Al could directly inhibit the PTH secretion, and at the same time might exert an indirect effect on PTH release "blunting" the serum Ca(+)+ variations.

Aluminum↗
PubMed1989

Aluminum toxicity in mammals: a minireview.

The element aluminum is ubiquitous in nature. Although its role in the metabolism of living systems remains to be elucidated, under certain circumstances aluminum is known to be toxic. The following topics concerning the toxicologic aspects of aluminum in mammals are covered in this brief review: major sources of the metal in humans, clinical toxicology, and experimental toxicology. Diagnosis, prevention and treatment of aluminum overload are also discussed in the clinical toxicology section. Moreover, acute and chronic toxicity studies, behavioral and neurofibrillary changes, mutagenicity, carcinogenicity, and reproductive and developmental effects of the metal are reviewed in the experimental toxicology section. Aluminum, under ordinary circumstances, can accumulate in patients receiving long-term hemodialysis, which has been associated with various severe disorders.

Aluminum↗
PubMed1989

[Influence of the degree of saturation of iron stores on the gastrointestinal absorption of aluminum].

The possible influence of iron metabolism in the regulation of aluminum gastrointestinal absorption in male Wistar rats has been studied. Three groups were considered: Fe overloaded Group 1; Fe normal Group 2; Fe depleted Group 3. All groups were exposed during 45 days to 40 mg of Al(OH)3 investigating the concentration of Al in serum and urine throughout the experiment and also the Al in brain at the end of that period. Results demonstrated that 24 h urinary Al excretion was significantly higher in Fe depleted rats than in Fe overloaded animals (p less than 0.01 and p less than 0.05 respectively). In addition, Al in brain showed the same pattern of deposition yielding in the Fe depleted rats nearly a three fold increase in the concentration of Al. By contrast, serum Al did not show any particular trend. These findings are in agreement with the fact that Fe metabolism may modulate Al gastrointestinal absorption suggesting that Al and Fe might share the same mechanism of gastrointestinal absorption.

Aluminum↗