RESUMEN
Energy dispersive X-ray spectroscopy (EDS) is a powerful technical tool used in the biomedical field to investigate the proportion of chemical elements of interest in research, such as heavy metal bioaccumulation and the enzymatic cofactors and nanoparticle therapy in various pathologies. However, the correct evaluation of the proportion of the elements is subject to some factors, including the method of sample preservation. In this study, we seek to investigate the effect of biological tissue preservation methods on the proportion of chemical elements obtained by the EDS methodology. For such, we used EDS to measure the proportion of chemical elements with biomedical interest in preserved livers, using three common methods for preserving biological tissues: (a) freezing, (b) paraformaldehyde fixative solution, and (c) Karnovsky solution. We found an increased level of sodium and reduced contents of potassium and copper in samples fixed in fixative solutions, when compared to frozen samples (p < 0.05). Our data indicate that preservation methods can change the proportion of chemical elements in biological samples, when measured by EDS. Frozen preservation should be preferred to retain the actual chemical content of samples and allow a correct assessment of the proportion of their elements.
Asunto(s)
Hígado/química , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Metales Pesados/análisis , Espectrometría por Rayos X , Conservación de Tejido , Animales , Masculino , RatonesRESUMEN
We describe the assembly of a hybrid electrophoresis device that contains fused silica capillaries interconnected to a microfabricated interface in a cross format for the determination of inorganic cations in biological samples. The sample transport in the proposed hybrid device was performed under gated injection mode and the separations were monitored with a capacitively coupled contactless conductivity detector. The capillary extremities were inserted into polypropylene tubes to create solution reservoirs. Sensing electrodes were produced using stainless-steel hypodermic needles previously cut with 2.0 mm length. The running composition and injection time were optimized and the best results were found using 50 mmol/L lactic acid, 20 mmol/L histidine and 3 mmol/L 18-crown-6 ether, and an electrokinetic injection time of 15 s. The separation of six inorganic cations was achieved with baseline resolution, and efficiencies were between 9.1 × 103 and 5.4 × 104 plates/m. The proposed hybrid device was explored for determining the concentration levels of inorganic cations in urine, saliva, and tear samples, employing Li+ as an internal standard. The achieved results were in good agreement with the data reported in the literature. The reliability of the proposed method ranged from 93 to 98%, thus suggesting satisfactory accuracy for bioanalytical applications.
Asunto(s)
Compuestos de Amonio/análisis , Líquidos Corporales/química , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Cationes/análisis , Conductividad Eléctrica , Electrodos , Electroforesis Capilar , Humanos , Dióxido de Silicio/químicaRESUMEN
Growing cacao (Theobroma cacao L.) in an agroforestry system generates a productive use of the land, preserves the best conditions for physical, chemical and biological properties of tropical soils, and plays an important role in improving cacao production and fertility of degraded tropical soils. The aim of this study was to evaluate the impact of two long term agroforestry systems of cacao management on soil physical and chemical properties in an area originally inhabited by 30 years old native secondary forest (SF). The two agroforestry systems adapted were: improved natural agroforestry system (INAS) where trees without economic value were selectively removed to provide 50% shade and improved traditional agroforestry system (ITAS) where all native trees were cut and burnt in the location. For evaluation of the changes of soil physical and chemical properties with time due to the imposed cacao management systems, plots of 10 cacao genotypes (ICS95, UF613, CCN51, ICT1112, ICT1026, ICT2162, ICT2171, ICT2142, H35, U30) and one plot with a spontaneous hybrid were selected. Soil samples were taken at 0-20, 20-40 and 40-60 cm depths before the installation of the management systems (2004), and then followed at two years intervals. Bulk density, porosity, field capacity and wilting point varied significantly during the years of assessment in the different soil depths and under the systems assessed. Soil pH, CEC, exchangeable Mg and sum of the bases were higher in the INAS than the ITAS. In both systems, SOM, Ext. P, K and Fe, exch. K, Mg and Al+H decreased with years of cultivation; these changes were more evident in the 0-20 cm soil depth. Overall improvement of SOM and soil nutrient status was much higher in the ITAS than INAS. The levels of physical and chemical properties of soil under cacao genotypes showed a marked difference in both systems.
Asunto(s)
Agricultura/métodos , Cacao/genética , Agricultura Forestal/métodos , Genotipo , Suelo/química , Cacao/metabolismo , Cationes Bivalentes , Cationes Monovalentes , Quimera , Concentración de Iones de Hidrógeno , Metales Alcalinos , Metales Alcalinotérreos , Perú , Fitomejoramiento , Árboles , Clima TropicalRESUMEN
Within all the eukaryotic cells there is an important group of biomolecules that has been potentially related to signalling functions: the myo-inositol phosphates (InsPs). In nature, the most abundant member of this family is the so called InsP6 (phytate, L(12-)), for which our group has strived in the past to elucidate its intricate chemical behaviour. In this work we expand on our earlier findings, shedding light on the inframolecular details of its protonation and complexation processes. We evaluate systematically the chemical performance of InsP6 in the presence and absence of alkali and alkaline earth metal ions, through (31)P NMR measurements, in a non-interacting medium and over a wide pH range. The analysis of the titration curves by means of a model based on the cluster expansion method allows us to describe in detail the distribution of the different protonated microspecies of the ligand. With the aid of molecular modelling tools, we assess the energetic and geometrical characteristics of the protonation sequence and the conformational transition suffered by InsP6 as the pH changes. By completely characterizing the protonation pattern, conformation and geometry of the metal complexes, we unveil the chemical and structural basis behind the influence that the physiologically relevant cations, Na(+), K(+), Mg(2+) and Ca(2+) have over the phytate chemical reactivity. This information is essential in the process of gaining reliable structural knowledge about the most important InsP6 species in the in vitro and in vivo experiments, and how these features modulate their probable biological functions.
Asunto(s)
Fosfatos de Inositol/química , Concentración de Iones de Hidrógeno , Ligandos , Espectroscopía de Resonancia Magnética , Metales Alcalinos/química , Metales Alcalinotérreos/química , Conformación Molecular , Ácido Fítico/química , ProtonesRESUMEN
Major problems with biological heart valves post-implantation are associated with progressive structural deterioration and calcification attributed to glutaraldehyde processing, dead cells, and cell fragments present in the native tissue. In spite of these problems, glutaraldehyde still is the reagent of choice. The results with acellular matrix xenograft usually prepared by detergent treatment in association with enzymes are rather conflicting because while preserving mechanical properties, tissue morphology and collagen structure are process dependent. This work describes a chemical approach for the preparation of an acellular bovine pericardium matrix intended for the manufacture of heart valve bioprostheses. Cell removal was performed by an alkaline extraction in the presence of calcium salts for periods ranging from 6 to 48 h. The results showed that cell removal was achieved after 12 h, with swelling and negative charge increasing with processing time. Nevertheless, collagen fibril structure, ability to form fibrils, and stability to collagenase were progressive after 24-h processing. There was no denaturation of the collagen matrix. A process is described for the preparation of acellular bovine pericardium matrices with preserved fibril structure and morphology for the manufacture of cardiac valve bioprostheses and may be used in other applications for tissue reconstruction.
Asunto(s)
Bioprótesis , Implantación de Prótesis de Válvulas Cardíacas/instrumentación , Prótesis Valvulares Cardíacas , Pericardio/trasplante , Animales , Rastreo Diferencial de Calorimetría , Bovinos , Colagenasas/metabolismo , Reactivos de Enlaces Cruzados/farmacología , Glutaral/farmacología , Humanos , Concentración de Iones de Hidrógeno , Hidrólisis , Ensayo de Materiales , Metales Alcalinos/farmacología , Metales Alcalinotérreos/farmacología , Microscopía Electrónica de Rastreo , Pericardio/citología , Pericardio/efectos de los fármacos , Pericardio/metabolismo , Pericardio/ultraestructura , Diseño de Prótesis , Factores de TiempoRESUMEN
The affinity of the Ca(2+) ion for a set of substituted carbonyl ligands was analyzed with both the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) methods. Two types of ligands were studied: a set of monosubstituted [O=CH(R)] and a set of disubstituted ligands [O=C(R)(2)] (R=H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either directly bound to the carbonyl carbon atom or to the para position of a phenyl ring. The interaction energy was calculated to quantify the affinity of the Ca(2+) cation for the ligands. Geometric and electronic parameters were correlated with the intensity of the metal-ligand interaction. The electronic nature of the substituent is the main parameter that determines the interaction energy. Donor groups make the interaction energy more negative (stabilizing the complex formed), while acceptor groups make the interaction energy less negative (destabilizing the complex formed).
Asunto(s)
Calcio/química , Carbono/química , Metales Alcalinotérreos/química , Compuestos Organometálicos/química , Cationes/química , Simulación por Computador , Enlace de Hidrógeno , Ligandos , Modelos Químicos , Estructura Molecular , Agua/químicaRESUMEN
DFT (B3LYP/6-31+G(d)) calculations of Mg(2+) affinities for a set of phosphoryl ligands were performed. Two types of ligands were studied: a set of trivalent [O = P(R)] and a set of pentavalent phosphoryl ligands [O = P(R)(3)] (R = H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either bound directly to the phosphorus atom or to the para position of a phenyl ring. The affinity of the Mg(2+) cation for the ligands was quantified by means of the enthalpy for the substitution of one water molecule in the [Mg(H(2)O)(6)](2+) complex for a ligand. The enthalpy of substitution was correlated with electronic and geometric parameters. Electron-donor groups increase the interaction between the cation and the ligand, while electron-acceptor groups decrease the interaction enthalpy.
Asunto(s)
Cationes/química , Magnesio/química , Ligandos , Metales Alcalinotérreos/química , Agua/químicaRESUMEN
Honey is the most popular bee product used by man, with nutritional and medicinal purposes. Its great diversity is attributed to numerous factors (bee type, visited flora, environment, and management). The quality of honey is controlled with routine parameters (free acidity, diastase activity, reducing sugars, ash, water, hydroxymethyfurfural, and sucrose contents). Besides the biochemical quality control, a functional profile is also important for pharmacological applications. In this work, bioactive indicators such as the antioxidant activity, flavonoid and polyphenol contents were evaluated by spectrophotometry, and correlated to the content of six bioelements (Ca, Cu, Fe, Mg, Mn, Zn) measured by atomic absorption spectroscopy, tandem FI-FAAS, in 14 unifloral Czech honeys. The antioxidant activity was 43.13 ± 53.72 mmoles TEAC/100 g honey. The flavonoid content was 5.18 ± 4.19 mg QE/100 g, and the polyphenol content was 45.38 ± 27.20 mg GAE/100 g. Buckwheat honey showed the highest values for these indicators of bioactivity, the acacia honeys the lowest, and the rest of the honeys were comprised between both of them. Honey content of bioelements was 138.19 ± 55.57 ppm Ca (min 77.11 - max 261.65), 0.33 ± 0.41 ppm Cu (min 0.00 - max 1.37), 2.95 ± 1.10 ppm Fe (min 1.34 - max 5.36), 35.08 ± 29.59 ppm Mg (min 8.76 - 128.06), 4.93 ± 3.99 ppm Mn (min 0.34 - max 11.31), 1.07 ± 0.56 ppm Zn (min 0.49 - max 2.52). The antioxidant activity of honey was significantly correlated to its content of cupper, iron, magnesium, manganese and zinc, but was not correlated to calcium.
La miel de abejas es el producto apícola más popular utilizado por el hombre, con fines nutricionales y medicinales. Su gran diversidad se atribuye a numerosos factores (tipo de abeja, flora visitada, ambiente, y manejo). La calidad de la miel se controla con parámetros de rutina: acidez libre, actividad de la diastasa, azúcares reductores, cenizas, humedad, hidroximetilfurfural, sacarosa aparente. Junto con el control de calidad bioquímica, también es importante su perfil funcional para aplicaciones farmacológicas. En este trabajo se evaluaron indicadores de bioactividad como la actividad antioxidante, el contenido de flavonoides y de polifenoles por espectrofotometría, y se correlacionaron con el contenido de seis bioelementos (Ca, Cu, Fe, Mg, Mn, Zn) determinados por espectroscopía de absorción atómica, IF acoplada a EAA con llama, en 14 mieles uniflorales checas. La actividad antioxidante fue 43.13 ± 53.72 mmoles TEAC/100 g miel. El contenido de flavonoides fue 5.18 ± 4.19 mg EQ/100 g, y el de polifenoles fue 45.38 ± 27.20 mg EAG/100 g. La miel de trigo sarraceno mostró los mayores valores en estos indicadores de bioactividad, las mieles de acacia los más bajos, y en el resto de las mieles estuvieron comprendidos entre ambos. El contenido de bioelementos en la miel fue 138.19 ± 55.57 ppm Ca (min 77.11 - max 261.65), 0.33 ± 0.41 ppm Cu (min 0.00 - max 1.37), 2.95 ± 1.10 ppm Fe (min 1.34 - max 5.36), 35.08 ± 29.59 ppm Mg (min 8.76 - 128.06), 4.93 ± 3.99 ppm Mn (min 0.34 - max 11.31), 1.07 ± 0.56 ppm Zn (min 0.49 - max 2.52). La actividad antioxidante de la miel se correlacionó significativamente con su contenido de cobre, hierro, magnesio, manganeso y zinc, pero no se correlacionó con el contenido de calcio.
Asunto(s)
Animales , Antioxidantes/análisis , Flavonoides/análisis , Flores/clasificación , Miel/análisis , Metales Alcalinotérreos/análisis , Metales Pesados/análisis , Polifenoles/análisis , Indicadores y Reactivos , Espectrofotometría AtómicaRESUMEN
Diaquabis[dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato-kappa(2)O,O']magnesium(II), [Mg(C(5)H(9)N(2)O(7)P(2))(2)(H(2)O)(2)], consists of isolated dimeric units built up around an inversion centre and tightly interconnected by hydrogen bonding. The Mg(II) cation resides at the symmetry centre, surrounded in a rather regular octahedral geometry by two chelating zwitterionic zoledronate(1-) [or dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonate] anions and two water molecules, in a pattern already found in a few reported isologues where the anion is bound to transition metals (Co, Zn and Ni). catena-Poly[[aquacalcium(II)]-mu(3)-[hydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato]-kappa(5)O:O,O':O',O''], [Ca(C(5)H(8)N(2)O(7)P(2))(H(2)O)](n), consists instead of a Ca(II) cation in a general position, a zwitterionic zoledronate(2-) anion and a coordinated water molecule. The geometry around the Ca(II) atom, provided by six bisphosphonate O atoms and one water ligand, is that of a pentagonal bipyramid with the Ca(II) atom displaced by 0.19 A out of the equatorial plane. These Ca(II) coordination polyhedra are ;threaded' by the 2(1) axis so that successive polyhedra share edges of their pentagonal basal planes. This results in a strongly coupled rhomboidal Ca(2)-O(2) chain which runs along [010]. These chains are in turn linked by an apical O atom from a -PO(3) group in a neighbouring chain. This O-atom, shared between chains, generates strong covalently bonded planar arrays parallel to (100). Finally, these sheets are linked by hydrogen bonds into a three-dimensional structure. Owing to the extreme affinity of zoledronic acid for bone tissue, in general, and with calcium as one of the major constituents of bone, it is expected that this structure will be useful in modelling some of the biologically interesting processes in which the drug takes part.
Asunto(s)
Difosfonatos/química , Hidrógeno/química , Imidazoles/química , Compuestos Organometálicos/química , Agua/química , Aniones/química , Cationes/química , Cristalografía por Rayos X , Ligandos , Metales Alcalinotérreos , Estructura Molecular , Solubilidad , Ácido ZoledrónicoRESUMEN
Vitamins and minerals play an important role in glucose metabolism, so understanding the impact of vitamin and mineral deficiencies and the potential utility of supplementation is relevant to the prevention and/or management of type 2 diabetes mellitus (DM). This review investigates current evidence for relationships between selected nutrients - vitamin B complex, antioxidants (vitamin A, C, E and carotenoids), calcium, vitamin D, vitamin K, magnesium, sodium, and potassium - and glucose metabolism. The investigation reveals current evidence is not strong enough for supplementation with minerals and vitamins to be recommended on a large scale for the prevention or management of DM. In order to prevent deficiencies and maintain health, the majority of diabetic individuals should receive daily vitamins and minerals within the ranges of recommended values from consumption of natural food sources and/or fortified foods. Further studies including large samples and longer follow-up periods are necessary to ascertain the benefits of mineral and vitamin supplementation to subsets of individuals who are at increased risk for DM or its complications.
Asunto(s)
Diabetes Mellitus Tipo 2/prevención & control , Diabetes Mellitus Tipo 2/terapia , Suplementos Dietéticos , Metales Alcalinos/administración & dosificación , Metales Alcalinotérreos/administración & dosificación , Vitaminas/administración & dosificación , Animales , Enfermedades Carenciales/complicaciones , Enfermedades Carenciales/metabolismo , Enfermedades Carenciales/prevención & control , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Glucosa/metabolismo , HumanosRESUMEN
Two of the main items from which to retrieve data in anthropology are teeth and bones. Identification of trace elements in their composition allows valuable information to be obtained about alimentary habits and community life conditions of groups and individuals. Conventional methods used to determine the presence of trace elements require sample preparation, with partial or total destruction of the pieces, which in most cases are unique. In this work we show the possibilities of laser-induced breakdown spectroscopy (LIBS) as a nearly nondestructive tool in anthropology and paleontology for the measurement of the presence and distribution of trace elements in teeth. We applied LIBS to the determination of strontium and magnesium in dentin and enamel of Neolithic, middle age, and modern Homo sapiens teeth. Mg/Ca and Sr/Ca distribution maps of dentin and enamel in modern teeth were created using the data obtained. Ablation threshold fluences of dentin and enamel were also measured using the photoacoustic signal induced by laser ablation. Significant variations were found in the Mg/Ca and Sr/Ca ratios in the tooth dental tissue and between the teeth of the groups and individuals studied. These results can be useful for evolutionary anthropology studies as they can provide information regarding early nutrition, seasonality, and residential mobility.
Asunto(s)
Dentina/química , Metales Alcalinotérreos/análisis , Paleodontología/métodos , Análisis Espectral/instrumentación , Análisis Espectral/métodos , Diente/química , Técnicas de Ablación , Acústica , Esmalte Dental/química , Diseño de Equipo , HumanosRESUMEN
Honey is the most popular bee product used by man, with nutritional and medicinal purposes. Its great diversity is attributed to numerous factors (bee type, visited flora, environment, and management). The quality of honey is controlled with routine parameters (free acidity, diastase activity, reducing sugars, ash, water, hydroxymethyfurfural, and sucrose contents). Besides the biochemical quality control, a functional profile is also important for pharmacological applications. In this work, bioactive indicators such as the antioxidant activity, flavonoid and polyphenol contents were evaluated by spectrophotometry, and correlated to the content of six bioelements (Ca, Cu, Fe, Mg, Mn, Zn) measured by atomic absorption spectroscopy, tandem FI-FAAS, in 14 unifloral Czech honeys. The antioxidant activity was 43.13 +/- 53.72 micromoles TEAC/100 g honey. The flavonoid content was 5.18 +/- 4.19 mg QE/100 g, and the polyphenol content was 45.38 +/- 27.20 mg GAE/100 g. Buckwheat honey showed the highest values for these indicators of bioactivity, the acacia honeys the lowest, and the rest of the honeys were comprised between both of them. Honey content of bioelements was 138.19 +/- 55.57 ppm Ca (min 77.11-max 261.65), 0.33 +/- 0.41 ppm Cu (min 0.00-max 1.37), 2.95 +/- 1.10 ppm Fe (min 1.34-max 5.36), 35.08 +/- 29.59 ppm Mg (min 8.76-128.06), 4.93 +/- 3.99 ppm Mn (min 0.34-max 11.31), 1.07 +/- 0.56 ppm Zn (min 0.49-max 2.52). The antioxidant activity of honey was significantly correlated to its content of cupper, iron, magnesium, manganese and zinc, but was not correlated to calcium.
Asunto(s)
Antioxidantes/análisis , Flavonoides/análisis , Flores/clasificación , Miel/análisis , Metales Alcalinotérreos/análisis , Metales Pesados/análisis , Polifenoles/análisis , Animales , Indicadores y Reactivos , Espectrofotometría AtómicaRESUMEN
B3LYP/6-311++G(d,p) calculations were used to predict some molecular properties of the C2H6N+...BeH2, C2H6N...MgH2, C3H8N...BeH2 and C3H8N+...MgH2 dihydrogen-bonded complexes. In these systems, it was demonstrated that the C2H6N+ and C3H8N+ protonated rings are potential candidates to bind with protonic hydrogens derived from alkaline earth metal compounds, BeH2 and MgH2. In terms of structural parameters and quantification of the dihydrogen bond energies, we should mention that the C2H6N+ three-membered ring provides the formation of stronger bound systems, which are 4.0 kJ mol-1 more stables than C3H8N+ four-membered ones. As complement, the analysis of the infrared spectrum indicated that red-shifts and blue-shifts are occurring in the N-H bonds of both C2H6N+ and C3H8N+ cationic rings. However, these two vibrational shifts were also verified on BeH2 and MgH2, what lead us to affirm that cationic compounds derived from small nitrogen rings and earth alkaline molecules are able to form unusual dihydrogen-bonded complexes by means of distinct spectroscopic phenomena, the red-shits and blue-shifts.
Asunto(s)
Azetidinas/química , Aziridinas/química , Cationes/química , Metales Alcalinotérreos/química , Protones , Enlace de Hidrógeno , Modelos Químicos , Modelos Teóricos , TermodinámicaRESUMEN
The role of monovalent (Na+, K+) and divalent (Ca2+, Mg2+) cations in Bufo arenarum fertilization was analysed. Our results showed that the highest fertilization percentages were obtained when strings of uterine oocytes (UO) were inseminated. Under these conditions, full jelly (FJ), which represents the jelly coats surrounding the oocytes at the time of deposition, contained 68.5 +/- 7.0 mM Na+, 27.4 +/- 2.4 mM K+, 6.3 +/- 0.9 mM Ca2+ and 6.9 +/- 0.9 mM Mg2+. When the strings of oocytes were washed in deionized water, these cations diffused into the liquid medium surrounding them. There was a marked similarity between the loss of Ca2+ in the jelly and the decrease in the fertilizability of the UO. Furthermore, the use of chelating agents of divalent cations showed the importance of the Ca2+ contained in the jelly. When Ca2+ was sequestered from the jelly coats by the addition of the chelating agents to the insemination medium as well as by pretreatment of the UO strings, a decrease in fertilization percentages occurred, this effect being dose dependent and more marked with EGTA. These results demonstrate that the Ca2+ in the jelly plays a role in fertilization. Nevertheless, taking into account that during the washing of the jelly other jelly coat components were diffused and considering that the addition of Ca2+ to the insemination medium reverted significantly, but only partially, the loss of fertilizability of jellied UO (washed), the participation of other components in the fertilization mechanism is suggested.
Asunto(s)
Bufo arenarum/fisiología , Matriz Extracelular/química , Fertilización , Metales Alcalinos/química , Metales Alcalinotérreos/química , Animales , Cationes Bivalentes/química , Cationes Monovalentes/química , Quelantes/farmacología , Ácido Edético/farmacología , Ácido Egtácico/farmacología , Femenino , Fertilización/efectos de los fármacos , MasculinoRESUMEN
An all-in-one version of a capacitively coupled contactless conductivity detector is introduced. The absence of moving parts (potentiometers and connectors) makes it compact (6.5 cm(3)) and robust. A local oscillator, working at 1.1 MHz, was optimized to use capillaries of id from 20 to 100 microm. Low noise circuitry and a high-resolution analog-to-digital converter (ADC) (21 bits effective) grant good sensitivities for capillaries and background electrolytes currently used in capillary electrophoresis. The fixed frequency and amplitude of the signal generator is a drawback that is compensated by the steady calibration curves for conductivity. Another advantage is the possibility of determining the inner diameter of a capillary by reading the ADC when air and subsequently water flow through the capillary. The difference of ADC reading may be converted into the inner diameter by a calibration curve. This feature is granted by the 21-bit ADC, which eliminates the necessity of baseline compensation by hardware. In a typical application, the limits of detection based on the 3sigma criterion (without baseline filtering) were 0.6, 0.4, 0.3, 0.5, 0.6, and 0.8 micromol/L for K(+), Ba(2+), Ca(2+), Na(+), Mg(2+), and Li(+), respectively, which is comparable to other high-quality implementations of a capacitively coupled contactless conductivity detector.
Asunto(s)
Electroquímica/instrumentación , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Calibración , Conductividad Eléctrica , Límite de DetecciónRESUMEN
OBJECTIVE: To assess the effects of evaporation and pasteurization of human milk on its biochemical and immunological composition and on its osmolarity. METHODS: The samples of mature human milk were categorized into four study groups: in natura human milk, pasteurized human milk, human milk evaporated at 70% of the baseline volume and human milk pasteurized and evaporated at 70%, with 12 different samples of milk in each group. The samples were used to determine the concentrations of sodium, potassium, calcium, phosphorus, magnesium, protein, fat, lactose, immunoglobulin A and osmolarity. RESULTS: The pasteurization of human milk did not show statistically significant changes in the concentration of sodium, potassium, calcium, phosphorus, magnesium, protein, fat, lactose, or in osmolarity; however, it showed remarkable reduction in the mean concentration of immunoglobulin A. Evaporation had a mean increase of 38% in the concentration of sodium, potassium, calcium, phosphorus, magnesium, protein, fat and lactose and mean reduction of 45% in the concentration of immunoglobulin A, without significant change in osmolarity in unprocessed milk. CONCLUSION: By evaporation at 70% of the baseline value of human milk, it is possible to obtain human milk that meets the nutritional requirements recommended for preterm infants, except for calcium and phosphorus.
Asunto(s)
Fórmulas Infantiles/normas , Fenómenos Fisiológicos Nutricionales del Lactante/fisiología , Leche Humana/química , Necesidades Nutricionales , Esterilización , Grasas/análisis , Calor , Humanos , Recién Nacido , Recien Nacido Prematuro/fisiología , Recién Nacido de muy Bajo Peso/fisiología , Lactosa/análisis , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Leche Humana/inmunología , Valor Nutritivo , Concentración Osmolar , Fósforo/análisis , VolatilizaciónRESUMEN
OBJETIVO: Avaliar os efeitos da evaporação e da pasteurização do leite humano na sua composição bioquímica e imunológica e em sua osmolaridade. MÉTODOS: As amostras de leite humano maduro foram divididas em quatro grupos de estudo: leite humano in natura, leite humano pasteurizado, leite humano evaporado a 70 por cento do volume inicial e leite humano pasteurizado e evaporado a 70 por cento, com 12 diferentes amostras de leite em cada grupo. Das amostras dos grupos, foram dosadas as concentrações de sódio, potássio, cálcio, fósforo, magnésio, proteína, gordura, lactose, imunoglobulina A e osmolaridade. RESULTADOS: A pasteurização do leite humano não mostrou alterações estatisticamente significantes na concentração dos elementos sódio, potássio, cálcio, fósforo, magnésio, proteína, gordura, lactose, nem na osmolaridade; no entanto, mostrou redução significante na concentração média de imunoglobulina A. A evaporação mostrou aumento estatisticamente significativo de 38 por cento em média na concentração dos elementos sódio, potássio, cálcio, fósforo, magnésio, proteína, gordura e lactose e redução média de 45 por cento na concentração da imunoglobulina A, sem alteração significativa da osmolaridade em relação ao leite sem processamento. CONCLUSÃO: Através da evaporação a 70 por cento do volume inicial do leite humano, pode ser obtido leite humano com condições de satisfazer as necessidades nutricionais preconizadas para o recém-nascido pré-termo, com exceção do cálcio e do fósforo.
OBJECTIVE: To assess the effects of evaporation and pasteurization of human milk on its biochemical and immunological composition and on its osmolarity. METHODS: The samples of mature human milk were categorized into four study groups: in natura human milk, pasteurized human milk, human milk evaporated at 70 percent of the baseline volume and human milk pasteurized and evaporated at 70 percent, with 12 different samples of milk in each group. The samples were used to determine the concentrations of sodium, potassium, calcium, phosphorus, magnesium, protein, fat, lactose, immunoglobulin A and osmolarity. RESULTS: The pasteurization of human milk did not show statistically significant changes in the concentration of sodium, potassium, calcium, phosphorus, magnesium, protein, fat, lactose, or in osmolarity; however, it showed remarkable reduction in the mean concentration of immunoglobulin A. Evaporation had a mean increase of 38 percent in the concentration of sodium, potassium, calcium, phosphorus, magnesium, protein, fat and lactose and mean reduction of 45 percent in the concentration of immunoglobulin A, without significant change in osmolarity in unprocessed milk. CONCLUSION: By evaporation at 70 percent of the baseline value of human milk, it is possible to obtain human milk that meets the nutritional requirements recommended for preterm infants, except for calcium and phosphorus.
Asunto(s)
Humanos , Recién Nacido , Fórmulas Infantiles/normas , Fenómenos Fisiológicos Nutricionales del Lactante/fisiología , Leche Humana/química , Necesidades Nutricionales , Esterilización , Volatilización , Grasas/análisis , Calor , Recien Nacido Prematuro/fisiología , Recién Nacido de muy Bajo Peso/fisiología , Lactosa/análisis , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Leche Humana/inmunología , Valor Nutritivo , Concentración Osmolar , Fósforo/análisisRESUMEN
Concentrations of calcium, magnesium, sodium and potassium were determined in 55 samples of mature human milk from Canary women and 5 samples of powdered infant formula. According to the literature our data fell within the normal intervals described for each kind of milk. The mean concentration of Ca, Mg, Na y K of powdered infant formula was higher than those concentrations found in the human milks. Significant differences among the concentrations of Ca, Mg and Na for the milks of the considered mothers were observed. Only the Ca intakes for infants fed with human milk were lower than those requirements recommended by the Food and Nutrition Board (1989). However, the infants fed with powdered infant formula had an adequate intake of all the studied metals. A progressive decrease of the Na, K and Ca concentrations with the lactation stage was observed. Maternal age, parity and sex of the newborns did not affect the metal concentrations significantly.
Asunto(s)
Humanos , Femenino , Recién Nacido , Lactante , Adulto , Alimentos Infantiles/análisis , Leche Humana/química , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Calcio/análisis , Magnesio/análisis , Polvos , Potasio/análisis , España , Sodio/análisisRESUMEN
Concentrations of calcium, magnesium, sodium and potassium were determined in 55 samples of mature human milk from Canary women and 5 samples of powdered infant formula. According to the literature our data fell within the normal intervals described for each kind of milk. The mean concentration of Ca, Mg, Na y K of powdered infant formula was higher than those concentrations found in the human milks. Significant differences among the concentrations of Ca, Mg and Na for the milks of the considered mothers were observed. Only the Ca intakes for infants fed with human milk were lower than those requirements recommended by the Food and Nutrition Board (1989). However, the infants fed with powdered infant formula had an adequate intake of all the studied metals. A progressive decrease of the Na, K and Ca concentrations with the lactation stage was observed. Maternal age, parity and sex of the newborns did not affect the metal concentrations significantly.
Asunto(s)
Alimentos Infantiles/análisis , Metales Alcalinos/análisis , Metales Alcalinotérreos/análisis , Leche Humana/química , Adulto , Calcio/análisis , Femenino , Humanos , Lactante , Recién Nacido , Magnesio/análisis , Potasio/análisis , Polvos , Sodio/análisis , EspañaRESUMEN
Origen y especificidad de iones metálicos en sistemas biológicos.- Bio-Inorgánica: Metodología y herramientas de trabajo, Captación y transformacián de elementos-traza por parte de los seres vivos.- Aspectos fundamentales de la Química Bio-inorgánica en elementos individuales: Hierro, Oxígeno, Nitrógeno, Cobre, Cinc, Molibdeno, Cobalto, Metales de transición, Alcalinos, Alcalino-térreos y No Metálicos, Mineralizació biológica.- Relaciones con otras ramas de la Ciencia y Técnica: Contaminación del medio ambiente, Toxicología, Medicina, Farmacología Inorgánica, Agricultura, Ganadería, Metalurgia y Procesos Industriales diversos