Chronic lead poisoning magnifies bone detrimental effects in an ovariectomized rat model of postmenopausal osteoporosis.

Lead (Pb) is a persistent environmental contaminant that is mainly stored in bones being an important source of endogenous lead exposure during periods of increased bone resorption as occurs in menopause. As no evidence exists of which bone biomechanical properties are impaired in those elderly women who had been exposed to Pb during their lifetime, the aim of the present study is to discern whether chronic lead poisoning magnifies the deterioration of bone biology that occurs in later stages of life. We investigated the effect of Pb in the femora of ovariectomized (OVX) female Wistar rats who had been intoxicated with 1000 ppm of Pb acetate in drinking water for 8 months. Structural properties were determined using a three-point bending mechanical test, and geometrical and material properties were evaluated after obtaining the load/deformation curve. Areal Bone Mineral Density (BMD) was estimated using a bone densitometer. Femoral histomorphometry was carried out on slices dyed with H&E (Hematoxylin and Eosin). Pb and OVX decreased all structural properties with a higher effect when both treatments were applied together. Medullar and cortical area of femurs under OVX increased, allowing the bone to accommodate its architecture, which was not observed under Pb intoxication. Pb and OVX significantly decreased BMD, showing lead treated ovariectomized rats (PbOVX) animals the lowest BMD levels. Trabecular bone volume per total volume (BV/TV%) was decreased in OVX and PbOVX animals in 54% compared to the control animals (p<0.001). Pb femurs also showed 28% less trabeculae than the control (p<0.05). We demonstrated that Pb intoxication magnifies the impairment in bone biomechanics of OVX rats with a consequent enhancement of the risk of fracture. These results enable the discussion of the detrimental effects of lead intoxication in bone biology in elderly women.

Lead bone toxicity in growing rats exposed to chronic intermittent hypoxia.

Lead chronic intoxication under hypoxic conditions revealed growth retardation in growing rats and damages on femoral and mandibular bones that predispose to fractures. These findings aimed us to investigate if bone material and geometric properties, bone mass in terms of histomorphometry or antioxidant capacity are also impaired in such experimental model. Combined treatments significantly reduced hemimandible cross sectional geometry and intrinsic stiffness (-16% and -34%); tibia and hemimandible bone volume (-45% and -40%) and growth plate cartilage thickness (-19%). These results show a previously unreported toxic effect of lead on mandible however, longer studies should be necessary to evaluate if an adaptation of bone architecture to maintain structural properties may occur and if the oxidative stress can be identified as the primary contributory agent in the pathogenesis of lead poisoning.

Effects of lead exposure on growth and bone biology in growing rats exposed to simulated high altitude.

The existence of children living at high altitude suffering from lead (Pb) poisoning prompted us to investigate the long term effects of this pollutant on growth and bone biology in growing rats maintained at simulated high altitude (SHA). Pb and hypoxia (HX) significantly reduced body weight (-9.4 % and -24 %; p < 0.01) and length (-3 % and -8 %; p < 0.01); decreased femoral ultimate load (-16 % and -40 %; p < 0.01) and femoral energy absorption capacity (-18 % and -74 %; p < 0.01). Oral pathologic alterations were observed in experimental groups. Our findings revealed growth retardation and damages on femoral and mandibular bones that predispose to fractures.

Zinc plasmático, cobre sérico y zinc y cobre eritrocitarios en adultos sanos de Buenos Aires / Plasmatic zinc, serum copper and erythrocyte zinc and copper levels in healthy adult people living in Buenos Aires

Se estudiaron adultos, clínicamente sanos, 21 varones (V) y 19 mujeres (M), de: edad (años): V: 48±14 (28-78); M: 41±14 (23-66); Índice de masa corporal (kg/m²): V: 26,7±2,3 (23,1-31,9); M: 22,2±3,5 (19,3-29,6). Se realizó una encuesta nutricional y se extrajo sangre en ayunas. Se realizaron las determinaciones de rutina del laboratorio clínico. Se determinó zinc en plasma (ZnPl), cobre en suero (CuS); en eritrocitos: Zinc (ZnGR) y cobre (CuGR), por espectrometría de absorción atómica. La totalidad de los V y M presentaron ingestas adecuadas de energía, proteínas, Zn y Cu. Los resultados expresados como: promedio ± desvío estándar y rangos fueron: ZnPl (μg/dL): V: 93±27 (49-161); M: 79±28 (42-157); ZnGR (μg/dL): V: 1.380±210 (1.110-2.010); M: 1.350±130 (1.090-1.520); CuS (μg/dL): V: 89±20 (40- 122); M: 93±28 (45-157). CuGR (μg/dL): V: 59±12 (37-78); M: 63±19 (30- 110). No se evidenciaron diferencias significativas entre V y M. Los resultados para la población estudiada fueron, percentilos 5 y 95, respectivamente: ZnPl: 49 a 131 μg/dL; ZnGR: 1.130 a 1.610 μg/dL; Zn/Hb: 34,4 a 47,5 μg/g; CuS: 45 a 124 μg/dL; CuGR: 36 a 78 μg/dL. Los valores de ZnPl y CuS se encuadraron dentro de los rangos de valores de referencia internacionales, sin diferencias significativas de acuerdo con el género.

Two groups of adult healthy people were studied: 21 males (M) and 19 females (F). Mean age (ys) was: M: 48±14 (28-78); F: 41±14 (23-66); body mass index (Kg/m²) was: M: 26.7±2.3 (23.1-31.9); F: 22.2±3.5 (19.3-29.6). A nutritional survey was recorded and mean daily intake of energy, protein, Zinc (Zn) and Copper (Cu) were calculated. Fasting blood samples were obtained in order to determine Hemoglobin (Hb), plasmatic Zn (PlZn), serum Cu (SCu), erythrocyte Zn (EZn) and erythrocyte Cu (ECu) levels. Zn and Cu were determined by AAS. Results were: mean±SD and ranges: PlZn (μg/dL): M: 93±27 (49-161); F: 79±28 (42-157); EZn (μg/dL): M: 1380±210 (1110-2010); F: 1350±130 (1090-1520); SCu (μg/dL): M: 89±20 (40-122); F: 93±28 (45-157). ECu (μg/dL): M: 59±12 (37-78); F: 63±19 (30-110). All individuals presented adequate intake of energy, protein, Zn and Cu. There were no significant differences between M and F for PlZn, EZn, Zn/Hb ratio, SCu and ECu. The results for the adult healthy population in Argentina, and which were in accordance with the international published values were: (percentiles 5 y 95, respectively): PlZn: 49 - 131 μg/dL; EZn: 1130 - 1610 μg/dL; Zn/Hb: 34,4 - 47,5 μg/g; SCu: 45 - 124 μg/dL; ECu: 36 - 78 μg/dL.

[Composition and potential contribution of iron, calcium and zinc of bread and pasta made with wheat and amaranth flours]. / Composición y aporte potencial de hierro, calcio y zinc de panes y fideos elaborados con harinas de trigo y amaranto.

Amaranth, a traditional american crop that is nowadays given renewed importance, has good food potential value. The minerals contributed by the grain are quantitatively important. However, as the flour is obtained by total grinding of the grain, this process leads to the presence of anti-nutritional components, such as fitates, and therefore, the evaluation of the actual availability of the minerals of nutritional interest becomes necessary. The process of bread fermentation, plus the addition of fitases and enhancers of mineral availability such as citric and ascorbic acid, might improve mineral bioavailability. The objective of this work was to assess protein, ash, lipids and total dietary fiber content and evaluate the concentration and dialyzability of Fe, Zn and Ca (as mineral bioavailability indicator) in bread and pasta 100% wheat, and bread and pasta obtained by replacing 20% wheat flour (WF) with whole amaranth flour (WAF). Ascorbic acid (AA), citric acid (CA) and fitase were used as mineral bioavailability enhancers. The potential contribution of each mineral (PC) was calculated as each mineral concentration times its dialyzability. In 80:20 bread an increase of total dietary fiber and minerals, compared to 100% wheat products was observed. A maximum FePC in 80:20 bread was obtained with CA and fitase (0.55mg%). In pasta, the maximum effect was observed with CA (0.07 mg%). The CaPC was maximum in 80:20 pasta with CA (16.72 mg%). The greatest ZnPC was found in 80:20 bread with CA and fitase (0.40 mg%). The introduction of the WAF in fermented baked products with addition of CA and fitase allows to obtain nutritional advantages.

Levels of essential and toxic elements in Porphyra columbina and Ulva sp. from San Jorge Gulf, Patagonia Argentina.

Baseline concentration levels of As, B, Ca, Cd, Cr, Cu, Co, Fe, Mg, Mn, Mo, Ni, P, Pb, Se, V, and Zn were determined for Porphyra columbina and Ulva sp. collected from three locations along San Jorge Gulf, in Patagonia Argentina. Elements were quantified by inductively coupled plasma-optical emission spectrometry, with the exception of lead and cadmium in some samples which were determined by electrothermal atomic absorption spectrometry. Three stations with different exposure degree to human activities, Bahía Solano, the mouth of Arroyo La Mata stream and Punta Maqueda, were selected as sampling points. The results showed a wide range of metal retention capacity between the two studied species. Regarding the levels of pollutants found in the researched sites, Punta Maqueda seemed to be less influenced by anthropogenic activities than the other two sites except for Cd. Taking into account their toxicities seasonal variations in Pb and Cd levels were studied in both algae in Punta Maqueda. Maximum concentrations of Cd (9.8 microg g(-1) dry wt.) were observed in P. columbina during winter, and maximum levels of Pb (0.82 microg g(-1) dry wt.) were detected in Ulva sp. during summer. Legislative and health safety aspects were evaluated for Cd and Pb.

Estudio sobre contaminación ambiental por plomo en niños de la localidad de Abra Pampa (Jujuy - Argentina) / Study of environmental lead contamination in children in the area around Jujuy - Argentina

El objetivo del estudio fue evaluar la exposición de los niños de Abra Pampa- Jujuy al plomo existente en el medio ambiente, proveniente de una fundición ubicada en el área urbana de esa ciudad que funcionó hasta finales de ladécada del 80 y en la que el mineral no fue retirado del lugar y se encuentra al descubierto. La investigación se realizó sobre 144 niños de ambos sexos, de edad comprendida entre 5 y 16 años, que representaron el 3,3 % de la población infantil de Abra Pampa. En todas las muestras se midió la actividad de la enzima ∂-ALA deshidratasa (método estandarizado europeo) y en 25 se determinó la plombemia (absorción atómica-atomización electrotérmica). De las 144 muestras estudiadas, el 3,5 % tuvieron valores de ∂-ALA deshidratasa inferiores al valor referencial (21 U/l). En el 40% de los casos estudiados (N=25) la plombemia estuvo por encima de 10 μg/dl. El máximo valor de plomo en sangre hallado fue de 41,3 μg/dl en un niño de 5 años. El hecho de haber encontrado valores de plomo elevados en los niños de Abra Pampa indica que la contaminación ambiental por este metal persiste, a pesar de la inactividad de la empresa y avalan la necesidad de su total erradicación así como la realizaciónde estudios clínicos-toxicológicos que comprenda a la población en riesgo (niños y mujeres embarazadas, principalmente) a fin de prevenir y/o tratar los múltiples efectos adversos provocados por el plomo.

The objective of this study was to evaluate the exposure of children from Abra Pampa, to environmental lead, which comes from an old smelting factory, located in the urban area of this city, that was opened until the late 1980's, and from where the mineralhas not been removed, so it still remains out in the open. The research was made using 144 blood samples from 5 to 16-year old children, both male and female, which represented 3.3% of the children population of Abra Pampa. In all of the samples, the activity of the enzyme ∂-aminolevulinic acid dehydratasewas determined (standardized European method) an in 25 of the samples, the lead blood levels were determined (atomic absorption - electro-thermal atomization). Of the 144 samples that were studied, 3.5% showed values of ∂-aminolevulinic acid dehydratase inferior to the reference values (21 U/L). In 40% of the cases studied (N = 25) lead blood levels were above the 10 ug/dl recommended by the Center ofDisease Control of USA. The highest level found was 41.3 ug/dl in a 5-year old child. The fact that we found high lead blood levels indicates that the environmental pollution still continues despite the closing of the factory, it also supports the need to fully eradicate it, as well as the need to make clinical and toxicological studies that includethe risk population (children and pregnant women, mainly) in order to prevent and/or treat the multiple adverse effects provoked by the metal.

Moderate zinc deficiency influences arterial blood pressure and vascular nitric oxide pathway in growing rats.

There is an increasing interest in the involvement of trace elements such as zinc in the pathogenesis of cardiovascular diseases. This study was designed to examine whether moderate zinc deficiency during growth influences blood pressure (BP) and vascular nitric oxide (NO) pathway. Three-week-old weaned male Wistar rats were randomly divided into two dietary groups and fed either a moderately zinc-deficient diet (zinc content 9 mg/kg; n = 12) or a control diet (zinc content 30 mg/kg; n = 12) for 60 d. The following were measured: systolic BP, nitrates and nitrites urinary excretion, urinary chemiluminescence intensity, NADPH-diaphorase activity in the thoracic aorta and intestinal arterioles, and NO synthase (NOS) catalytic activity using L-[U14C]-arginine as substrate in the thoracic aorta. Zinc deficiency during growth induced an increase in BP from day 30 of the experimental period, leading to hypertension on day 60. Animals that were fed the zinc-deficient diet had lower urinary excretion levels of nitrates and nitrites and higher intensity of spontaneous luminescence on day 60. At the end of the experiment, zinc-deficient rats showed decreased NADPH diaphorase activity in endothelium and smooth muscle of the thoracic aorta and intestinal arterioles and decreased activity of NOS in thoracic aortic tissue. An imbalance in zinc bioavailability during postnatal and growing periods may be may be a risk factor in development of cardiovascular alterations in adult life. The mechanisms involved may include an impaired vascular NO system as a result of decreased NOS activity and higher systemic oxidative stress.

Bioavailability of microencapsulated ferrous sulfate in powdered milk produced from fortified fluid milk: a prophylactic study in rats.

OBJECTIVE: We investigated the iron bioavailability of microencapsulated ferrous sulfate (SFE-171) in a diet based on powdered milk by using the prophylactic method in rats. METHODS: The SFE-171 was added into fluid milk and industrially processed into powdered milk, which was then mixed in our laboratory with a normalized diet (17.2 +/- 2.1 mg Fe/kg). A reference standard diet using ferrous sulfate as iron-fortifying source (19.8 p+/- 2.9 mg Fe/kg) and a control diet without added iron (4.6 +/- 0.8 mg Fe/kg) were prepared in the laboratory in a similar way. These diets were administered to different groups of weaning rats for 28 d as the only solid nourishment. The iron bioavailability of the different sources was calculated as the relation between the mass of iron incorporated into hemoglobin during the treatment and the total iron intake per animal. RESULTS: The iron bioavailability values of SFE-171 and ferrous sulfate in the fortified diets were 41.6 +/- 6.6% and 42.6 +/- 4.2%, respectively; these results were significantly higher (P < 0.01) than the iron bioavailability of the control diet (28.8 +/- 8.1%). CONCLUSION: These results showed that iron-fortified powdered milk can be produced from fluid milk fortified with SFE-171. The bioavailability of SFE-171 in this rat model was not altered by the manufacturing process.