RESUMO
Introducción: Los GOS son prebióticos naturales presentes en la leche materna que pue-den obtenerse enzimáticamente a partir de la lactosa de leche de vaca durante la fabricación de yogur. El producto lácteo resultante será reducido en lactosa y contendrá prebióticos y bacterias potencialmente probióticas. Sin embargo, mantendrá la baja relación Ca/Pi que aporta la leche de vaca, lo que podría alterar el remodelamiento óseo y la mineralización. Objetivo: comparar si un yogur reducido en lactosa que contiene GOS (YE) ofrece ventajas adicionales respecto de un yogur regular sin GOS (YR) sobre las absorciones (Abs) de Ca y Pi, retención y calidad ósea durante el crecimiento normal. Al destete, ratas machos fueron divididas en 3 grupos alimentados con AIN Ì93-G (C), YE o YR durante 28 días. Resultados: YE mostró el mayor aumento de lactobacilos fecales; producción de ácidos grasos de cadena corta especialmente p, profundidad de las criptas colónicas y menor pH cecal. El %AbsCa y %AbsPi aumentó en el siguiente órden: YE> YR> C (p < 0,05). El contenido de Ca y Pi en fémur, la densidad y contenido mineral óseos y los parámetros biomecánicos fueron similares en YE y C, mientras que YR mostró valores significativa-mente menores (p < 0,05). Conclusiones: YE aumentó las Abs y biodisponibilidad de minerales, alcanzando la retención y calidad ósea de C. El aumento en las Abs observado en YR no logró obtener la retención y calidad ósea de C. Conclusión: YE habría contrarrestado el efecto negativo del mayor aporte de Pi de la leche de vaca y sería una buena estrategia para lograr el pico de masa ósea y calidad del hueso adecuados, especialmente en individuos intolerantes a la lactosa. (AU)
Breast milk contains an optimal calcium/phosphate (Ca/Pi) ratio and GOS. These natural prebiotics can be enzymatically produced via cow's milk lactose inyogurt manufacture. This milk product is low in lactose and contains prebiotics and potentially probiotic bacteria but maintains a low Ca/Pi ratio that could alter bone remodeling and mineralization. We evaluated if a lactose-reduced yogurt containing GOS (YE) offers additional advantages over regular yogurt without GOS (YR) on Ca and Pi absorption (Abs), bone retention and quality during normal growth. Weaning male rats were divided into 3 groups fed AIN'93-G (C), YE or YR for 28 days. Results: YE showed the highest increase in fecal lactobacilli; short-chain fatty acids production, especially propionate and butyrate; intestine crypt depth, and the lowest cecal pH. AbsCa% and AbsPi% increased in this order: YE> YR> C (p <0.05). Ca and Pi content in femur, bone density and mineral content, and biomechanical parameters were similar in YE and C, while YR showed the significantly lowest value (p < 0.05). Conclusions: YE increased mineral Abs reaching the retention and bone quality of C. Although YR increased Abs, bone retention and quality did not achieve C values. Seemingly, YE compensated for the negative effect of the higher Pi supply and would be a good strategy to achieve adequate peak bone mass and bone quality, especially in lactose intolerant individuals. (AU)
Assuntos
Animais , Ratos , Oligossacarídeos/metabolismo , Osteogênese/fisiologia , Cálcio da Dieta/farmacocinética , Fósforo na Dieta/farmacocinética , Absorção Intestinal/fisiologia , Lactose/metabolismo , Magnésio/farmacocinética , Tíbia/anatomia & histologia , Iogurte/análise , Cálcio da Dieta/metabolismo , Absorciometria de Fóton , Densidade Óssea , Interpretação Estatística de Dados , Fósforo na Dieta/metabolismo , beta-Galactosidase/síntese química , Ratos Wistar , Lactobacillus delbrueckii/isolamento & purificação , Fêmur/anatomia & histologia , Intestino Grosso/anatomia & histologia , Magnésio/metabolismo , Valor NutritivoRESUMO
Menopause is associated with bone loss. Prebiotics increase Ca, inorganic phosphorus (Pi), and Mg absorption, improving bone health. These increases would supply an extra amount of minerals, decreasing bone resorption and possibly reversing ovariectomy-induced bone loss. The present experimental study sought to evaluate the effect of adding a prebiotic GOS/FOS® mixture to a normal or a low Ca diet on Ca, Pi, and Mg absorption, in osteopenic rats. Four groups of n = 8 rats each were OVX, and 8 rats were SHAM operated. All rats were fed a commercial diet for 45 days. They were then fed one of the following diet for 45 days: C-0.5%: SHAM fed AIN 93 M containing 0.5%Ca; O-0.5% and O-0.3%: OVX rats fed AIN 93 M, containing 0.5% or 0.3%Ca, respectively; GF-0.5% and GF-0.3%: OVX rats fed AIN 93 M, containing 0.5% or 0.3%Ca+ 2.5% GOS/FOS®, respectively. At the end of the experimental time point, Ca, P, and MgAbs% was significantly higher in GF-0.5% and GF-0.3% as compared to the remaining groups (p < 0.01). Irrespective of diet Ca content, CTX decreased whereas femur Ca and P content, tibia BV/TV and GPC.Th, lumbar spine and proximal tibia BMD, bone strength, bone stiffness, and elastic modulus increased in the GF-0.5% and GF-0.3% groups as compared to O-0.5% and O-0.3%, respectively (p < 0.05). This prebiotic mixture would be a useful tool to prevent the increase in bone loss associated with menopause and aging.
Assuntos
Doenças Ósseas Metabólicas/metabolismo , Osso e Ossos/efeitos dos fármacos , Cálcio da Dieta , Dieta , Absorção Intestinal/efeitos dos fármacos , Oligossacarídeos/farmacologia , Animais , Densidade Óssea/efeitos dos fármacos , Doenças Ósseas Metabólicas/etiologia , Doenças Ósseas Metabólicas/patologia , Osso e Ossos/fisiologia , Cálcio/deficiência , Cálcio/metabolismo , Cálcio/farmacocinética , Cálcio da Dieta/administração & dosagem , Cálcio da Dieta/farmacocinética , Dieta/métodos , Suplementos Nutricionais , Feminino , Frutose/química , Frutose/farmacologia , Galactose/química , Galactose/farmacologia , Oligossacarídeos/administração & dosagem , Ovariectomia , Ratos , Ratos WistarRESUMO
Se describe la validación de un método para la determinación de manganeso, molibdeno y zinc, a niveles traza, en soluciones acuosas, mediante espectroscopia de emisión-plasma inductivo de argón. Se optimizó y validó la cuantificación de manganeso, molibdeno y zinc en solución acuosa ácida usando un espectrómetro de emisión atómica de plasma inductivo. Se determinaron: selectividad/especificidad, linealidad, repetibilidad y precisión intermedia utilizando materiales de referencia, y sesgo contrastando contra material de referencia certificado de matriz. Las longitudes de onda (nm) seleccionadas fueron: Zn 213.857, Mn 257.610 y Mo 202.031, las cuales permitieron discriminar interferencias espectrales. Se probó la linealidad de las funciones respuesta mediante evaluaciones estadísticas ad hoc. La precisión intermedia varió entre 5 y 11% y el sesgo no superó el 12%. Los límites de cuantificación (μg/L) fueron: Mn: 5; Zn: 10 y Mo: 10. Las incertidumbres asociadas a las determinaciones oscilaron entre 10 y 16%. La validación del método propuesto demostró que es selectivo, proporciona incertidumbres adecuadas y es de utilidad para cuantificar de manera rápida y certera los metales traza estudiados en matrices que puedan ser llevadas a solución acuosa, previa digestión en medio ácido.
A method to accurately determine and quantify manganese, molybdenum and zinc using Optical Emission Spectroscopy-Inductively Coupled Plasma by optical emission spectrometer was optimized and validated. Selectivity/ specificity, linearity, repeatability, intermediate precision and bias using reference materials and certified matrix reference material, respectively, were determined. Selected wavelengths (nm) Zn 213.857; Mn 257.610 and Mo 202.031 made it possible to discriminate spectral interferences. Linearity was proved by ad hoc statistical evaluations. Intermediate precision ranged between 5 and 11% and bias was never greater than 12%. Quantification limits (mg/L) were: Mn: 5; Zn: 10 y Mo: 10. Uncertainties associated to analytical determinations ranged between 10% and 16%. The validation of the proposed method demonstrated that it is selective, it provides adequate uncertainties and it is useful to quantify quickly and accurately the studied trace metals in matrices that can be taken intoaqueous solution with prior digestion in acid medium.
Descreve-se a validação de um método para a determinação de manganês, molibdênio e zinco a níveis-traço, em soluções aquosas, por Espectrometria de emissão por plasma acoplado indutivamente de argônio. Foi maximizada e validada a quantificação de manganês, molibdênio e zinco em solução aquosa ácida, utilizando um espectrômetro de emissão atômica por plasma acoplado indutivamente. Foram determinados: seletividade/especificidade, linearidade, repetibilidade e precisão intermediária usando materiais de referência, e viés contrastando contra material de referência certificado de matriz. Os comprimentos de onda (nm) selecionados foram: Zn 213.857; Mn 257.610 e Mo 202.031, os quais permitiram discriminar interferências espectrais. A linearidade das funções resposta foi provada por avaliações estatísticas ad hoc. A precisão intermediária variou entre 5 e 11% e o viés não ultrapassou 12%. Os limites de quantificação (μg/L) foram: Mn: 5; Zn: 10 e Mo: 10. As incertezas associadas com as determinações variaram entre 10 e 16%. A validação do método proposto demonstrou que é seletivo, proporciona incertezas adequadas e é útil para quantificar com rapidez e precisão os metais-traço estudados em matrizes que podem ser levadas a solução aquosa, prévia digestão em meio ácido.
Assuntos
Zinco/análise , Manganês/análise , Molibdênio/análise , Métodos de Análise Laboratorial e de Campo , Padrões de ReferênciaRESUMO
El contenido de calcio (Ca) y de compuestos que afectan su absorción son relevantes en dietas ricas en harinas integrales y frutos secos, tanto en vegetarianos estrictos, individuos con intolerancia a lácteos, como en celíacos. Se determinaron Ca, fibra dietaria y perfil de inositoles fosfato (IP) en harinas integrales/refinadas y/o extrudidas de cereales (trigo, maíz, arroz, sorgo), pseudocereales (trigo sarraceno, amaranto), leguminosas (arveja), oleaginosas (soja, lino). Se cuantificó Ca por espectrometría de absorción atómica, fibra dietaria por método enzimático-gravimétrico y perfil de IP por HPLC. Mediante factores de conversión, se calculó el contenido de ácido fítico (AF) y la relación molar AF/Ca como indicador de su disponibilidad potencial. El Ca (mg/100 g) fue muy bajo en harinas de cereales (<20 trigo refinada, maíz integral, arroz integral, sorgo integral y refinada), en pseudocereales fue variable (4 trigo sarraceno, 115 amaranto) y fue superior en harinas de arveja, soja y lino (102-257) pero no aumentó en galletitas con agregado de estas últimas harinas. El contenido de fibra dietaria fue acorde al grado de extracción (1,4-13,3 g/100 g). En todos los casos la relación molar AF/Ca superó 0,17-0,24, valor límite que disminuiría la absorción del Ca.
Calcium (Ca) content and compounds that affect its absorption are relevant in wholemeal flours and tree nuts. These foods are specially recommended for vegetarians, people with intolerance to dairy products and celiac patients. Ca, dietary fibre and inositol profile (IP) where analyzed in wholemeal/refined/ extruded flours, in cereals (wheat, maize, rice, sorghum), pseudocereals (buckwheat, amaranth), leguminous (peas) and oilseeds (soy, flax). Ca was assessed by atomic absorption spectrometry, dietary fibre using an enzymatic method and IP profile by HPLC. Phytic acid content (AF) was obtained using conversion factors. Molar ratio AF/Ca was calculated as an index of potential Ca availability. Ca (mg/100 g) was very low in cereal flours (<20 in refined wheat, wholemeal maize and rice and refined and wholemeal sorghum). In pseudocereals, Ca varied (4 buckwheat, 115 amaranth). It was high in peas, soy and flax (102-257), but this was not enough to improve Ca in cookies made with these mix flours. Dietary fibre content was coincidental with the extraction grade (1.4-13.3/100 g). In all cases, AF/Ca molar ratios exceeded 0.17-0.24, limit value that represents the negative effect of AF over calcium availability.
O teor de cálcio (Ca) e de compostos que afetam sua absorção são relevantes em dietas ricas em farinhas integrais e frutos secos, tanto em vegetarianos rigorosos, indivíduos com intolerância a laticínios e quanto celíacos. Determinaram-se Ca, fibra alimentar e perfil inositol fosfato (IP) em farinhas integrais/refinadas e/ ou extruidas de cereais (trigo, milho, arroz, sorgo), pseudocereais (trigo sarraceno, amaranto), leguminosas (ervilha), oleaginosas (soja, linhaça). Quantificou-se Ca por espectrometría de absorção atômica, fibra alimentar pelo método enzimático-gravimétrico e perfil de IP por HPLC. A través de fatores de conversão foi calculado o conteúdo de ácido fítico (AF) e a relação molar AF/Ca como indicador de sua disponibilidade potencial. O Ca (mg/100 g) foi muito baixo em farinhas de cereais (<20 trigo refinada, milho integral, arroz integral, sorgo integral e refinada), em pseudocereais foi variável (4 trigo sarraceno, 115 amaranto) e foi superior em farinhas de ervilha, soja e linhaça (102-257), mas não aumentou em biscoitos com estas últimas farinhas adicionadas. O conteúdo de fibra alimentar foi conforme ao grau de extração (1,4-13,3 g/100 g). Em todos os casos a relação molar AF/Ca superou 0,17-0,24, valor limite que diminuiria a absorção do Ca.
Assuntos
Cálcio/análise , Análise de Alimentos/estatística & dados numéricos , Alimentos, Dieta e NutriçãoRESUMO
INTRODUCTION: During growth, protein deprivation impairs epiphyseal growth plate (EGP) height, bone volume (BV) and endochondral ossification. During catch-up growth, Ca availability becomes essential to ensure the extra amount needed to achieve optimal peak bone mass and strength. GOS and FOS improve mineral absorption in the colon. PURPOSE: The effect of a mixture of GOS/FOS® 9:1 added to a 0.5 %Ca (NCa) and a 0.3 %Ca (LCa) diets on Ca, P and Mg absorptions and bone mineralization, density and structure using an experimental model of growing rats recovering from early protein malnutrition was investigated. METHODS: To induce protein malnutrition, rats were fed a low protein diet: 4 % (LPD) during 1 week and then were randomly assigned to recovery groups (R) until day 50 (T = 50) as follows: R0.5 %: NCa; RP0.5 %: NCa + 5.3 % GOS/FOS®; R0.3 %: LCa and RP0.3 %: LCa + 5.3 % GOS/FOS®. Control groups received the 0.5 %Ca or 0.3 %Ca diet from weaning until day 40 or 50. RESULTS: Body weight and length increased in C groups throughout the study; both were arrested in all R during LPD consumption and increased immediately after re-feeding. Independently of dietary Ca content, LS counts, ß-glucosidase and Ca, P and Mg absorption increased, whereas cecum pH, ß-glucuronidase, urease and tryptophanase decreased in RP0.5 %: and RP0.3 %: as compared to the other studied groups (p < 0.01). Prebiotic consumption decreased CTX levels and increased femur Ca, Mg and P contents, total skeleton bone mineral content, proximal tibia and spine BMD, BV, EGP height and hypertrophic zone thickness, stiffness and elastic modulus as compared to recovery groups fed the prebiotic-free diets. CONCLUSION: Under the present experimental conditions, GOS/FOS® mixture induced colonic positive effects, which increased Ca, P and Mg absorption. Thus, consuming the prebiotic-containing diet resulted in an extra amount of minerals that improved bone development in growing rats recovering from protein malnutrition.
Assuntos
Cálcio da Dieta/farmacocinética , Oligossacarídeos/administração & dosagem , Desnutrição Proteico-Calórica/tratamento farmacológico , Trissacarídeos/administração & dosagem , Animais , Disponibilidade Biológica , Peso Corporal , Densidade Óssea/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Calcificação Fisiológica/efeitos dos fármacos , Cálcio da Dieta/administração & dosagem , Cálcio da Dieta/sangue , Ceco/efeitos dos fármacos , Ceco/metabolismo , Dieta , Fezes/química , Fêmur/efeitos dos fármacos , Fêmur/fisiologia , Glucuronidase/metabolismo , Lâmina de Crescimento/efeitos dos fármacos , Lâmina de Crescimento/fisiologia , Absorção Intestinal , Magnésio/administração & dosagem , Magnésio/sangue , Magnésio/farmacocinética , Masculino , Oligossacarídeos/sangue , Oligossacarídeos/farmacocinética , Fósforo na Dieta/administração & dosagem , Fósforo na Dieta/sangue , Fósforo na Dieta/farmacocinética , Prebióticos/administração & dosagem , Desnutrição Proteico-Calórica/sangue , Ratos , Ratos Wistar , Trissacarídeos/sangue , Trissacarídeos/farmacocinética , Triptofanase/metabolismo , Urease/metabolismoRESUMO
AIM: Increasing calcium intake is the most effective strategy for avoiding Ca deficit. However, if intake remains inadequate, improving Ca absorption becomes an important tool to optimize Ca homeostasis and bone health. PURPOSE: The effect of a mixture of GOS/FOS(®) 9:1 added to a normal- or low-Ca diets on Ca absorption and bone mineralization, density and structure was investigated, in a model of growing rats. Several colonic parameters to help support the findings were also evaluated. RESULTS: Weanling Wistar rats received one of the four experimental AIN-93G diets: C5: 0.5% Ca; C3: 0.3% Ca; P5: 0.5% Ca + 5.3% GOS/FOS(®); P3: 0.3% Ca + 5.3% GOS/FOS(®) until 50 days (T = 50). At T = 50, lactobacillus and cecum weights were higher, whereas cecum pH was lower in P5 and P3 versus C5 and C3 (p < 0.001). At T = 50, fecal Ca, Mg and P were lower and their absorptions (mg/dL) were higher in P5 and P3 versus C5 and C3, respectively (p < 0.05). Ca, Mg and P absorption % was higher in P5 and P3 versus C5 and C3 (p < 0.001). Femur Ca and P content, bone mineral content, trabecular bone mineral density, tibia length, bone volume, osteoblast surface, stiffness and elastic modulus were higher in P5 and P3 versus C5 and C3 (p < 0.05). Despite the lower Ca content, P3 group reached similar values than C5 in all these latter parameters. CONCLUSIONS: Supplementing diets with the GOS/FOS(®) mixture increased bone mineralization, density and structure due to an increase in Ca, P and Mg absorptions. Thus, this prebiotic mixture may help to improve bone development in a period of high calcium requirements.
Assuntos
Osso e Ossos/efeitos dos fármacos , Cálcio da Dieta/administração & dosagem , Galactose/administração & dosagem , Oligossacarídeos/administração & dosagem , Prebióticos/administração & dosagem , Animais , Fenômenos Biomecânicos , Densidade Óssea/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Osso e Ossos/fisiologia , Calcificação Fisiológica/efeitos dos fármacos , Cálcio da Dieta/farmacocinética , Dieta , Interações Medicamentosas , Fezes/química , Absorção Intestinal , Masculino , Ratos , Ratos WistarRESUMO
PURPOSE: A low calcium intake (LCaI) may predispose to obesity, and excessive fat mass may be detrimental to bone. The impact of Ca inadequacy would be greater in subjects predisposed to obesity. LCaI effect on obesity development during the rapid growth period was compared in two strains of rats: spontaneously obese IIMb/ß (O) and Wistar (W). Pregnant rats were fed 0.5% (N) or 0.2% (L) of Ca (OLCa, ONCa, WLCa and WNCa). Male pups were fed the maternal diet until day 60. METHODS: Body composition, lipid profile, glucose homeostasis, 25 hydroxyvitamin D, Ca-phosphorus, and bone metabolism were evaluated. RESULTS: BW and body fat were higher, whereas body protein was lower in OLCa versus ONCa (p < 0.05). OLCa presented the highest body fat, glucose, non-HDL and total cholesterol, TGL, insulin levels, and HOMA-IR, liver weight, and adipose perigonadal plus retroperitoneal pads (p < 0.05). WLCa did not exhibit an increase BW and only showed a slight change in body composition with minor biochemical alterations compared to WNCa (p < 0.05). Osteocalcin, CTX, and proximal tibia and lumbar spine BMDs were lower in O than in W rats fed the same Ca diet (p < 0.05). Body ash and Ca content, and total skeleton BMC/BW were lower in OLCa and WLCa versus their corresponding NCa groups (p < 0.05). CONCLUSION: The negative effect of a low Ca diet on fat mass accumulation and lipid profile may be more evident in rats predisposed to obesity. Nevertheless, low CaI interferes with the normal glucose homeostasis leading to an increase in insulin resistance. Low CaI during early growth may be an obesogenic factor that may persist into adult life and may account for the development of obesity and some of its co-morbidities.
Assuntos
Cálcio/deficiência , Dieta/efeitos adversos , Obesidade/etiologia , Osteoporose/etiologia , Adiposidade , Animais , Densidade Óssea , Remodelação Óssea , Cálcio da Dieta/administração & dosagem , Cálcio da Dieta/uso terapêutico , Feminino , Resistência à Insulina , Lactação , Masculino , Fenômenos Fisiológicos da Nutrição Materna , Obesidade/metabolismo , Obesidade/patologia , Obesidade/prevenção & controle , Osteoporose/metabolismo , Osteoporose/patologia , Osteoporose/prevenção & controle , Gravidez , Distribuição Aleatória , Ratos Endogâmicos , Ratos Wistar , Desmame , Aumento de PesoRESUMO
INTRODUCTION: Obese ß rats may be a suitable model to evaluate the association between calcium intake (CaI) and obesity during growth. OBJECTIVE: The present study comparatively evaluated Ca absorption and retention, and changes in body composition in spontaneously genetically obese (ß) male rats fed three different dietary Ca levels: high 0.9% (HCa); normal: 0.5% (NCa); low: 0.2% (LCa). METHODS: Pregnant rats were fed isocaloric diets which varied in Ca content only. Male pups continued feeding the same maternal diet until postnatal day 60. The percentage of Apparent Ca absorption (CaA %), Ca balance (CaB), body composition, glucose, triglycerides (TGL), and insulin levels were evaluated. RESULTS: Food consumption and body weight (BW) were higher in Group LCa than in Groups NCa and HCa (p < 0.01); no differences were observed between the latter two groups. Group LCa presented the highest body fat, liver weight, perigonadal and retroperitoneal fat (p < 0.05); conversely, body ashes and total skeleton bone mineral content were significantly lower compared with animals in both the NCa (p < 0.01) and HCa groups (p < 0.01). CaB (mg/day) reached a plateau at the highest CaI (mg/day) value (r = 0.985, p < 0.001). CaA%, serum glucose, insulin, and TGL levels rose as CaI decreased (p < 0.01). CONCLUSIONS: Although further studies are required, low Ca consumption in this strain of rats could modulate BW inducing changes in several lipid metabolism parameters, which in turn lead to an increase in body fat.
Assuntos
Composição Corporal , Cálcio da Dieta/farmacocinética , Cálcio/metabolismo , Obesidade/genética , Adiposidade , Animais , Peso Corporal , Dieta , Feminino , Lactação , Metabolismo dos Lipídeos , Masculino , Gravidez , Taxa de Gravidez , Ratos , Triglicerídeos/sangueRESUMO
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.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Zinco/sangue , Cobre/sangue , Argentina , Valores de Referência , Biomarcadores/sangueRESUMO
Se evaluó el efecto de la suplementación con Fe sobre la variación del Zn sanguíneo y urinario en 36 mujeres, clínicamente sanas, atendidas durante la gestación en el Hospital D. Paroissien (La Matanza, Buenos Aires). A la primera consulta (To) (edad gestacional: 17 ± 3 semanas) se realizó una encuesta de recordatorio de 24 hs., calculando la ingesta de Zn (lZn); se determinó en sangre entera, extraída en ayunas: Zn (ZnS) (espectrofotometría de absorción atómica, EAA) y Hemoglobina (Hb); en suero: ferritina (ELISA); en orina basal (la segunda de la mañana, con ayuno de líquidos y sólidos): Zn (EAA) y Creatinina (Crea), método de Jaffé. Las gestantes con Hb < 11 g/dL y aquellas con Hb > 11 g/dL, pero con ferritina < 12 ng/mL (Gfe, n =13) recibieron 100 mg/día de Fe (maltosato férrico); las mujeres con Hb > 11 g/dL y ferritina > 12 ng/mL constituyeron el grupo control (GC, n = 23). A las semanas 26 ± 2 (T1) y 35 ± 2 (Tf) se repitieron las determinaciones de laboratorio. Los promedios ± DE fueron, para GC y GFe, respectivamente: To: lZn (mg/día): 5,7 ± 2,3; 6,6 ± 4,2 (ns); Hb (g/dL):12,4 ± 0,9; 11,0 ± 1,0 (p<0,05); ferritina (ng/mL): 100 ± 81; 54 ± 40 (p <0,05); ZnS (mg/d/L): 528 ± 81; 545 ± 116; Zn/Crea (mg/g): 0,53 ± 0,34; 0,42 ± 0,33; T1; Hb(g/dL): 11,1 ± 1,3; 10,0 ± 1,4; ferritina }(ng/mL): 106 ± 108; 11 ± 3 (p < 0,05); ZnS (ug/dl): 506 ± 77; 517 ± 111; Zn/Crea (mg/g): 0,52 ± 0,16; 0,48 ± 0,23; Tf: Hb (g/dL): 10,5 ± 1,5; 10,5 ± 1,3; ferritina (ng/mL): 16 ± 12; 14 ± 9 (ns); ZnS (mg/dl): 569 ± 99; 545 ± 90; Zn/Crea (mg/g): 0,50 ± 0,10; 0,61 ± 0,29. No existieron diferencias significativas en ZnS ni en Zn/crea entre GC y GFe a To ni durante el estudio. Estos resultados indican que la administración de suplementos de Fe alejada de las comidas no afecta los niveles de Zn eritrocitario ni la eliminación urinaria basal durante la gestación en los rangos de ingesta de Zn del presente estudio.
Assuntos
Humanos , Zinco/urina , Zinco/sangue , Suplementos Nutricionais , Ferro , GestantesRESUMO
Se evaluó el efecto de la suplementación con Fe sobre la variación del Zn sanguíneo y urinario en 36 mujeres, clínicamente sanas, atendidas durante la gestación en el Hospital D. Paroissien (La Matanza, Buenos Aires). A la primera consulta (To) (edad gestacional: 17 ± 3 semanas) se realizó una encuesta de recordatorio de 24 hs., calculando la ingesta de Zn (lZn); se determinó en sangre entera, extraída en ayunas: Zn (ZnS) (espectrofotometría de absorción atómica, EAA) y Hemoglobina (Hb); en suero: ferritina (ELISA); en orina basal (la segunda de la mañana, con ayuno de líquidos y sólidos): Zn (EAA) y Creatinina (Crea), método de Jaffé. Las gestantes con Hb < 11 g/dL y aquellas con Hb > 11 g/dL, pero con ferritina < 12 ng/mL (Gfe, n =13) recibieron 100 mg/día de Fe (maltosato férrico); las mujeres con Hb > 11 g/dL y ferritina > 12 ng/mL constituyeron el grupo control (GC, n = 23). A las semanas 26 ± 2 (T1) y 35 ± 2 (Tf) se repitieron las determinaciones de laboratorio. Los promedios ± DE fueron, para GC y GFe, respectivamente: To: lZn (mg/día): 5,7 ± 2,3; 6,6 ± 4,2 (ns); Hb (g/dL):12,4 ± 0,9; 11,0 ± 1,0 (p<0,05); ferritina (ng/mL): 100 ± 81; 54 ± 40 (p <0,05); ZnS (mg/d/L): 528 ± 81; 545 ± 116; Zn/Crea (mg/g): 0,53 ± 0,34; 0,42 ± 0,33; T1; Hb(g/dL): 11,1 ± 1,3; 10,0 ± 1,4; ferritina }(ng/mL): 106 ± 108; 11 ± 3 (p < 0,05); ZnS (ug/dl): 506 ± 77; 517 ± 111; Zn/Crea (mg/g): 0,52 ± 0,16; 0,48 ± 0,23; Tf: Hb (g/dL): 10,5 ± 1,5; 10,5 ± 1,3; ferritina (ng/mL): 16 ± 12; 14 ± 9 (ns); ZnS (mg/dl): 569 ± 99; 545 ± 90; Zn/Crea (mg/g): 0,50 ± 0,10; 0,61 ± 0,29. No existieron diferencias significativas en ZnS ni en Zn/crea entre GC y GFe a To ni durante el estudio. Estos resultados indican que la administración de suplementos de Fe alejada de las comidas no afecta los niveles de Zn eritrocitario ni la eliminación urinaria basal durante la gestación en los rangos de ingesta de Zn del presente estudio.(AU)
Assuntos
Humanos , Suplementos Nutricionais , Zinco/urina , Zinco/sangue , Ferro , Deficiências de Ferro , GestantesRESUMO
Indicators of maternal iron (Fe) status were studied in relation to placental Fe (Pl-Fe) status. Placental (Pl) and maternal (M) venous blood samples were obtained from primiparous women (n = 38), with normal delivery at Paroissien Hospital, Argentina. Maternal hemoglobin (M Hb), soluble transferrin receptor (M sTfR) (ELISA) and serum ferritin (M S-Ft) were studied in relation to Pl-Fe, ferritin (Pl-Ft) and transferrin receptor (Pl-TfR). Pl-TfR was measured by dot blot assay, Pl-Ft and M S-Ft by immunoassay (IRMA) and Pl-Fe by atomic absorption spectrometry. Fe status indicators were, respectively, (mean +/- SD): M Hb 113 +/- 16 g/L; M S-Ft 36 +/- 42 microg/L; M sTfR 6.3 +/- 3.1 mg/L; Pl-Fe 170 +/- 56 microg/g placenta; Pl-Ft 33 +/- 18 microg/g placenta; Pl-TfR 18 +/- 18 (range 0-58) microg/g placenta. Pl-Fe, Pl-Ft and Pl-TfR did not correlate to M Hb, M S-Ft and M sTfR. Women with Pl- Fe, Pl-Ft and Pl-TfR above or below the corresponding median values did not show any statistical significant difference in M Hb, M sTfR or M S-Ft values. Pl-Ft concentration was lower in women with Hb < 110 g/L than in women with normal values: 26 +/- 13 vs. 38 +/- 20 microg/g, respectively (p = 0.021). When Pl-TfR, Pl-Ft and Pl-Fe were compared in women with M S-Ft above or below the cut-off point of 10 or 20 microg/L, no significant difference was found for Pl-TfR neither for Pl-Ft nor Pl-Fe. These results suggest that maternal indicators of Fe status, particularly M sTfR and M S-Ft, do not reflect Fe status of the placenta at delivery.
Assuntos
Parto Obstétrico , Ferro/sangue , Mães , Placenta/química , Adolescente , Adulto , Feminino , Ferritinas/sangue , Hemoglobinas/metabolismo , Humanos , Gravidez , Receptores da Transferrina/sangue , Estatística como AssuntoRESUMO
Orange juice may be a nutrient vehicle that helps to improve diet quality. The addition of whey allows the incorporation of high quality proteins. However, a good acceptability is necessary. The aims of the present study were: a) to assess the acceptability of a beverage prepared with orange juice (J) and whey powder (WP) at 7 g/100 g (J+WP7) or at 13 g/100 g (J+WP13); b) to measure available lysine content and ascorbic acid retention of the more accepted formulation, comparing the effect of HIPEF treatment (29 kV/cm, t(acum): 59 micros) with a conventional heat treatment at 75 degrees C, for 15 minutes (HT). The beverages were subjected to sensory evaluation (Friedman test). Available lysine was assessed by the Carpenter method, modified by Booth, and vitamin C by HPLC; minerals Na and K, by flame photometry; Ca, Mg and Zn by atomic absorption spectrometry. There were no significant differences between the acceptance of J and J+WP7. J+WP13 was significantly less accepted (p < 0.01), so it was discarded. Available lysine (mg/g protein) in untreated J+WP7 was 60.2 +/- 0.15; after treatments: 50.0 +/- 2.8 (HT) and 51.0 +/- 3.4 (HIPEF). The HIPEF treated J and (J+WP7) retained 100% and 98% of their vitamin C initial content and the HT treated, 91% and 88%, respectively. The amount of whey powder added to the orange juice conditioned the acceptability. The juice containing 7% of whey powder was well accepted, and after treatment by HIPEF, it retained a good nutritional quality, regarding available lysine, vitamin C retention and provision of mineral nutrients.
Assuntos
Ácido Ascórbico/análise , Bebidas , Citrus/química , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Lisina/análise , Animais , Bebidas/análise , Bebidas/normas , Estimulação Elétrica , Conservação de Alimentos/normas , Frutas/química , Temperatura Alta , Leite , Valor NutritivoRESUMO
Pica is the compulsive intake of non-nutritive substances such as earth, clay, chalk, soap and ice. The most common forms of pica are geophagia or the intake of earth and pagophagia or the intake of ice. The description of this peculiar phenomenon dates back to the Greco-Roman civilization. Its prevalence during pregnancy is generally underestimated. Published data reveal a prevalence of between 8% and 65%. Investigations from Latin America indicate a prevalence of 23% to 44%. It is not clear yet which are the causes that predispose to pica, but they are frequently associated with anemia or iron deficiency during pregnancy. Its diagnosis, which only consists in questioning pregnant women, is generally omitted during prenatal care, probably because health professionals have no knowledge about this disorder. The identification of pica in pregnant women could contribute to the detection of a risk group where it is necessary to implement strategies as regards both the evaluation and the nutritional education.
Assuntos
Pica/epidemiologia , Complicações na Gravidez/epidemiologia , Anemia Ferropriva/diagnóstico , Anemia Ferropriva/epidemiologia , Feminino , Humanos , Pica/diagnóstico , Pica/etiologia , Gravidez , Complicações na Gravidez/diagnóstico , Complicações na Gravidez/etiologia , Complicações Hematológicas na Gravidez/diagnóstico , Complicações Hematológicas na Gravidez/epidemiologia , Complicações Hematológicas na Gravidez/etiologia , PrevalênciaRESUMO
La ferritina sérica (FS), indicadora de depósitos de hierro (Fe), es cuestionable en el puerperio, mientras que el receptor soluble de transferrina (RsT) parecería más confiable. Por ello, se estudió la FS en las 24 h post parto en 88 mujeres atendidas en el Hospital Diego Paroissien. Se determinó: Hematocrito (Hto), Hemoglobina (Hb), recuento de glóbulos rojos (GR) y blancos (GB); en suero: RsT, FS y Proteína C-Reactiva. Se analizó sensibilidad y especificidad de FS mediante el modelo del operador-receptor (ROC), considerando al RsT como "estándar de oro". Los valores (media ± DE y rangos) fueron: Hto (%) 35 ± 5 (22 - 47); Hb (g/L) 112 ± 17 (61 - 150); GR x 103/mm3 3.843 ± 530 (2.500 - 5.300); GB/mm3 9.644 ± 2.599 (5.300 - 21.000); RsT (mg/L) 4,93 ± 2,93 (0,54 - 14,77); FS (µg/L) 33 ± 39 (0 - 210); PCR (+) en 92,4% de los casos. FS evidenció un área bajo la curva de 0,795 con elevada sensibilidad (83%) y especificidad de 63% para un punto de corte de 25 µg/L. Además, FS correlacionó con RsT (r = -0,436) y con el cociente RsT/FS (r = -0,919). Estos resultados sugieren que FS sería de utilidad en el post parto inmediato, siendo aconsejable utilizar el punto de corte de 25 µg/L.
Serum ferritin (SF) may not be a reliable indicator of iron (Fe) stores during the puerperium. Therefore, it was compared to the soluble transferrin receptor (sTfR) in 24 h post partum women (n = 88), assisted at Diego Paroissien Hospital (Buenos Aires, Argentina). Hematocrit (Hct), hemoglobin (Hb), red blood cells (RBC) and white blood cells (WBC) were determined in fasting blood samples using an electronic counter (Mega); SF by ELISA (IMx Ferritina, Abbott); sTfR by ELISA (Orion Diagnostica) and C-Reactive Protein (PCR-Latex, Wiener lab). Statistical analysis (Receiver Operating Characteristics, ROC) were performed using the sTfR as "gold standard". Results: (mean ± SD) (range): Hct (%) 35 + 5 (22 - 47); Hb (g/L) 112 ± 17 (61 - 150); RBC x 103/mm3 3843 ± 530 (2500-5300); WBC/mm3 9644±2599 (5300 -21000); sTfR (mg/L) 4.93 ± 2.93 (0.54 - 14.77); SF(µg/L) 33 ± 39 (0 - 210); PCR (+) in 92.4%. Sensitivity and specificity of SF were, respectively: 83% and 63% for a cut-off point of 25 µg /L (area under ROC plot 0.795, 95% reference interval: 0.694 - 0.897). SF correlated inversely with sTfR (r = -0.436) and with the sTfR/SF ratio (r = -0.919). These results suggest that SF may be a useful indicator of maternal Fe stores during the early perinatal period, although its cost may limit rutinary laboratory use.
Assuntos
Humanos , Feminino , Gravidez , Ferritinas , Anemia , Anemia/complicações , Anemia/prevenção & controle , Anemia/sangueRESUMO
La pica se manifiesta por la ingesta persistente y compulsiva de sustancias no nutritivas como tierra, arcilla, tiza, jabón y hielo. Las formas más comunes son la geofagia o consumo de tierra y la pagofagia o consumo de hielo. La descripción de este peculiar fenómeno se remonta a la época de la civilización greco-romana. Su presencia durante el embarazo es generalmente poco estudiada o subestimada, los datos publicados indican que puede manifestarse con una prevalencia que varía del 8 por ciento al 65 por ciento. Las cifras provenientes de investigaciones en América Latina refieren una prevalencia del 23 por ciento al 44 por ciento. No está claro aún cuáles son las causas que predisponen a este trastorno, sin embargo es frecuente su presencia en gestantes que presentan anemia o un estado nutricional deficiente con respecto al hierro. Su diagnóstico, que sólo consiste en interrogar sobre esta práctica a las gestantes, es frecuentemente ignorado durante la atención prenatal, probablemente debido al desconocimiento por parte del equipo de salud respecto a este trastorno. La identificación de la práctica de pica durante el embarazo contribuirá a detectar un grupo de gestantes con riesgo nutricional, en quienes sea necesario implementar estrategias tanto de evaluación como de educación nutricional
Assuntos
Gravidez , Anemia , Pica , Gravidez , Argentina , Ciências da Nutrição , ObstetríciaRESUMO
The chemical composition of green seaweed, Monostroma undulatum, Wittrock, growing in the Southern Argentina coast, was studied. Samples were collected in Puerto Deseado, province of Santa Cruz (47 degrees 45'L.S., 65 degrees 55'L.W.), from October to December 1999 and 2000. It has been analyzed six sample during this period. Algae were washed with sea water and dried at room temperature for 24 hs. Moisture, nitrogen, lipids and ashes were determined according to AOAC; fiber (total, soluble and insoluble), according to Lahaye. After mineralization with nitric acid, sodium and potassium were determined by flame photometry, calcium by complexometric method, and phosphorus by Gomori's method. The ranges expressed per 100 g dry algae were: protein (Nx6.25): 12.89-21.85; ashes (g): 33.92-40.05; lipid (g): 0.32-1.47; total fiber (g): 14.36-19.6; digestible carbohydrates (calculated by difference) (g): 20.86-32.48; sodium (g): 7.39-13.11; potassium (g): 1.38-3.18; calcium (mg): 149-226; phosphorus (mg): 190-447; Vitamin C (mg): 159-455. These results show that this green seaweed is an important source for protein, fiber, macronutrients minerals and vitamin C, during the macroscopic period. There was an important fluctuation that must be taken into account to consider the commercial collection to use it in human nutrition.
Assuntos
Ácido Ascórbico/análise , Clorófitas/química , Minerais/análise , Alga Marinha/química , Argentina , Fibras na Dieta/análise , Humanos , Necessidades Nutricionais , Valor Nutritivo , Estações do AnoRESUMO
The effect of dietary calcium (Ca) level on maternal zinc (Zn) nutritional status was studied. Female Wistar rats, weighing 250-350 g, were fed during pregnancy and lactation with an experimental diet containing/100 g different levels of calcium: 0.2 g (low calcium: LCa), 0.6 g (normal calcium: NCa) or 0.9 (high calcium: HCa). Maternal blood samples were drawn from the tail at delivery and at the end of lactation. Laboratory determinations were: Zn in whole blood (WB) at delivery and weaning; Zn (ZnF) and Ca (CaF) in the ashed femur at weaning. The results (mean +/- SEM) were: ZnWB (microgram/ml) at delivery and weaning: LCa: 8.73 +/- 1.05; 12.8 +/- 2.02; NCa: 3.49 +/- 0.19; 3.73 +/- 0.37; HCa: 3.21 +/- 0.19; 3.85 +/- 0.27. CaF (mg/100 mg): LCa: 19.2 +/- 0.8; NCa: 21.4 +/- 0.6; HCa: 20.4 +/- 1.1. ZnF (microgram/100 mg): LCa: 30.2 +/- 0.9; NCa: 24.1 +/- 0.3; HCa: 24.1 +/- 0.9. ZnWB was significantly higher in LCa (p < 0.0001) regarding NCa and Hca. ZnF showed an increase and CaF a decrease in LCa regarding NCa and HCa (p < 0.0001). There were no significant differences in ZnWB, ZnF and CaF between NCa and HCa These results show that: there was no detrimental effect when dietary Ca content was increased by 50% above the normal requirements of the rat.; low dietary Ca during pregnancy and lactation produced an increase of Zn utilization, reflected in maternal blood Zn and in ZnF content.
Assuntos
Cálcio da Dieta/administração & dosagem , Fêmur/metabolismo , Lactação , Gravidez , Zinco/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta , Feminino , Fêmur/química , Lactação/metabolismo , Estudos Longitudinais , Ratos , Ratos Wistar , Zinco/sangueRESUMO
The effect of low dietary calcium on maternal zinc nutritional status was studied. Two groups of 6 adult female Wistar rats were fed during pregnancy and lactation with experimental diets containing either 0.2 g (LCa) or 0.6 g (NCa) of calcium/100 g. Both diets contained/100 g: 20.0 g protein (potassium caseinate), 3.5 mg Zn, 0.6 g P. A third group (n = 6) was fed a "stock diet" (SG), containing/100 g: 24.8 g protein, 1.5 g Ca, 0.6 g P, 11.6 mg Zn. Maternal blood samples were drawn from the tail before mating (To), at delivery (D) and at weaning (W); dams were sacrificed at weaning and the right femur was excised. Determinations (atomic absorption spectrometry) were: Zinc in red blood cells (RBC), Zn and Ca in ashed femur. The results (mean +/- SD) were: RBCZn (microg/mL) at To: 8.65 +/- 1.80, which did not change in the SG or in the NCa groups, but increased significantly in the LCa group (p < 0.001) (D: 18.20 +/- 4.63; W: 26.70 +/- 6.02), regarding To. Femur Zn (microg/100 mg) showed an increase (p < 0.001) in the LCa group (30.2 +/- 2.1) regarding both SG (25.3 +/- 0.7) and NCa groups (24.1 +/- 0.7). Femur Ca (mg/100 mg) decreased (p < 0.05) in the LCa group (19.2 +/- 0.9) regarding both SG (24.0 +/- 0.5) and NCa groups (21.4 +/- 0.7) and leading to a significant increase in Zn/Ca ratio (p < 0.001) in the LCa group. Therefore, dietary calcium deficiency during pregnancy and lactation would produce an increase of Zn utilization, reflected in the increase of maternal blood Zn levels and in femur Zn content.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Osso e Ossos/metabolismo , Cálcio/farmacologia , Lactação/metabolismo , Zinco/sangue , Zinco/metabolismo , Animais , Cálcio da Dieta , Feminino , Gravidez , Prenhez , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Se estudiaron 14 mujeres, de 22 a 35 años, premenopaúsicas, clínicamente sanas, residentes en Comodoro Rivadavia (Chubut), con valores normales de densidad mineral ósea de columna lumbar y cuello de fémur; los promedios ñ DE de peso e índice de masa corporal fueron, respectivamente: 57,7 ñ 3,8 (kg); 21,8 ñ 1,7 kg/m². La ingesta de calcio (ICa) se calculó en base a una encuesta alimentaria. En orina basal (A), con sobrecarga de agua (B) y de 24 h (C), se determinaron: calcio (Ca), deoxipiridinolina (D-Pir) y creatinina (crea), calculando las relaciones Ca/crea y D-Pir/crea. Los resultados promedio ñ DE fueron: ICa (mg/día): 720 ñ 284; Ca/crea (mg/mg): A: 0,065 ñ 0,039; B: 0,050 ñ 0,022; C: 0,089 ñ 0,027; D-Pir/crea (nM/mM) A: 5,9 ñ 2,2; B: 5,5 ñ 2,0; C: 5,1 ñ 1,4. Ca/crea en A y B no fueron significativamente menores que C (p 0,025); Ca/crea en C correlacionó con ICa (p = 0,002). D-Pir/crea en A, B y C no fueron diferentes. Estos resultados sugieren que: 1) las muestras A y B podrían utilizarse indistintinamente para determinar las relaciones urinarias Ca/crea y D-Pir/crea; 2) Ca/crea en C muestra una elevada correlación con ICa; 3) los valores normales de densidad de masa ósea (DMO) y D-Pir/crea en éstas mujeres premenopaúsicas, indican una adaptación al amplio rango de ICa (AU)