Calcium as a nutrient involved in the synthesis and localization of proteins that facilitate iron uptake and efflux in enterocytes / El calcio como nutriente implicado en la síntesis y localización de proteínas que participan en la captación y eflujo del hierro en los enterocitos

Iron deficiency is the most common type of nutritional deficiency in the world, and calcium intake is low in many populations. Developing a supplement that contains both micronutrients would be an excellent method to prevent iron deficiency and increase calcium intake. Human and cellular studies have shown that calcium inhibits iron absorption. Currently, the mechanisms underlying this inhibitory effect have not been elucidated. Because calcium is involved in cell signaling pathways, it may affect the regulation of the expression or localization of proteins involved in iron uptake and efflux in enterocytes. The aim of this review was to describe the processes involved in the absorption of dietary iron and the regulation of the expression and activity of proteins involved in this absorption. Additionally, the potential mechanisms by which calcium affects the expression and localization of these proteins are also discussed.

La deficiencia de hierro es la deficiencia nutricional más común en el mundo y la ingesta de calcio es baja en la mayoría de poblaciones. El desarrollo de un suplemento que contenga ambos micronutrientes sería una excelente estrategia para prevenir la deficiencia de hierro y aumentar la ingesta de calcio. Estudios en humanos y en células han demostrado que el calcio inhibe la absorción del hierro. Actualmente los mecanismos que explican este efecto inhibitorio no están claramente dilucidados. Dado que el calcio está implicado en la señalización celular, podría afectar la regulación de la expresión y localización de proteínas implicadas en la captación y eflujo de hierro en los enterocitos. El objetivo de esta revisión es describir los procesos implicados en la absorción del hierro dietario y la regulación de la expresión y actividad de las proteínas implicadas en esta absorción. Además, se discutirán los posibles mecanismos por los cuales el calcio afecta la expresión y localización de esas proteínas.

Dehydroepiandrosterone effect on Plasmodium falciparum and its interaction with antimalarial drugs.

Dehydroepiandrosterone (DHEA) inhibits glucose 6-phosphate dehydrogenase (G6PDH) of different species and may potentially decrease intracellular glutathione. Therefore, it can have and enhance anti-parasitic action against Plasmodium spp. We evaluated the antiplasmodial activity and the interaction of DHEA with several antimalarial drugs. The inhibitory effect of DHEA on erythrocytic and G6PDH activity and changes in the content of total and reduced gluthatione Plasmodium falciparum content were also evaluated. DHEA showed antiplasmodial activity in vitro, but the potency was low (IC(50) 118.5 µM). DHEA inhibits G6PDH from healthy erythrocyte and decreases GSH content in both erythrocytes and P. falciparum. DHEA did not synergize or antagonize the antiplasmodial effect of several antimalarial drugs. The most important actions of DHEA were the inhibition of G6PDH activity, and the decrease in both P. falciparum and erythrocyte GSH. Since most of the GSH in Plasmodium spp. infected erythrocytes comes from the parasite itself, it is possible that DHEA analogs could act with higher selectivity, better potency, and might interact synergistically with antimalarials drugs.

Effect of an antioxidant drink on homocysteine levels in Alzheimer's patients.

BACKGROUND: A large body of evidence supports a role of oxidative stress in Alzheimer disease (AD) and in cerebrovascular disease. Blood levels of homocysteine may be increased in AD and hyperhomocysteinemia may contribute to disease pathophysiology by vascular and direct neurotoxic mechanisms. Even in the absence of vitamin deficiency, plasma total homocysteine (tHcy) concentration may be influenced by administration of polyphenols. OBJECTIVE: To determine the effect of an antioxidant beverage rich in polyphenols on the plasmatic levels of tHcy in Alzheimer's patients. DESIGN, SETTING, AND PATIENTS: A multicenter, randomized, double-blind controlled clinical trial of polyphenols supplementation in 100 subjects (52 of control group, 24 AD patients in initial phase and 24 AD patients in moderate phase) (Mini-Mental State Examination scores between 14 and 26, inclusive). Fasting plasma concentrations of tHcy, folate and vitamin B(12) were measured before (Ti) and after (Tf) the ingestion of the beverage. The study was conducted at clinical research places of the Catholic University San Antonio and University Hospital Virgen de la Arrixaca of Murcia (Spain). INTERVENTION: Participants of the three groups were randomly assigned to 2 groups of the same size: 50% treated with antioxidant beverage rich in polyphenols and 50% treated with an identical placebo beverage. Subjects consumed 1 brick (200 mL/day) of antioxidant drink or placebo drink for 8 months. RESULTS: Higher tHcy levels were observed in the AD moderate phase patients (Ti:12.65±1.21 µmol/L) than in the AD initial phase patients (Ti:9.13±1.24 µmol/L) and in the control group (Ti:9.86±0.77 µmol/L). Lower folate levels were observed in the AD moderate phase patients (Ti:8.20±1.29 ng/mL) than in the AD initial phase patients (Ti:9.41±1.56 ng/mL) and in the control group (Ti:12.32±0.67 ng/mL). Antioxidant drink vs placebo drink attenuated the tHcy increase in the control group (Tf values of 11.74±0.45 vs 15.63±1.79 µmol/L) and AD patients, especially in the moderate phase (Tf: 10.49±0.73 vs 16.58±2.73 µmol/L). CONCLUSIONS: The regular ingestion of polyphenols contained in an antioxidant beverage may decrease tHcy plasmatic concentrations in Alzheimer's patients.

Evaluación del estado nutricional de mujeres gestantes que participaron de un programa de alimentación y nutrición / Assessment of nutritional status of a group of pregnant women who participated in a food and nutrition program

Objective: To evaluate the nutritional status of a group of pregnant women and their newborn infants participating in the MANA program. Methods: Descriptive, longitudinal and prospective study designed to follow the cohort before and after intervention. Results: 53 percent of the household showed food insecurity. With the program, food ingestion had a significant increase and the prevalence of the risk of micronutrient deficiency diminished. The low gestational weight diminished from 27.8 percent in the first trimester to 20.3 percent in the third trimester. 94 percent of the newborns weighed over 2500 g. Anemia were prevented in 86 percent of the mothers with iron deficiency. The mothers at risk of serum foliate deficiency diminished from 30,8 percent in the first trimester to 11 ,5 percent in the second. Conclusion: Since the socioeconomic conditions of the population were unchanged during the study, it is possible to conclude that the MANA program and the products received had a positive and significant impact in the nutritional status of the mothers.

Objetivo: Evaluar el estado nutricional de un grupo de gestantes y sus recién nacidos participantes del programa MANA para la vida. Método: Estudio descriptivo, longitudinal, prospectivo con seguimiento de la cohorte antes y después de una intervención. Resultados: el 53 por ciento de los hogares se percibieron en inseguridad alimentaria. La ingesta de nutrientes tuvo un incremento significativo y se redujo la prevalencia del riesgo de deficiencia de algunos micronutrientes. El bajo peso gestacional disminuyó de 27,8 por ciento en el primer trimestre a 20,3 por ciento en el tercero. El 94 por ciento de los recién nacidos tuvieron un peso superior a 2500g. La anemia se previno en el 86 por ciento de las madres con deficiencia de hierro y se disminuyó la proporción a riesgo de deficiencia de folato. Conclusión: Dado las condiciones socioeconómicas de la población, se concluye que el programa desarrollado y los productos entregados tuvieron un impacto positivo y significativo en el estado nutricional de las madres.

Effects of hyperoxia on biomarkers of oxidative stress in closed-circuit oxygen military divers

Oxygen toxicity is a problem in diving which can have fatal consequences in thewater. When divers use closed-circuit oxygen rebreathing apparatus they are takingonly oxygen 100% and this hyperoxic exposure increases the generation of reactiveoxygen species (ROS) in biological tissues. The objective of the present study is toevaluate the effects of hyperoxia on biomarkers of oxidative stress in closed-circuitoxygen military divers. Fifteen professional divers of Spanish Navy Diving Centreparticipated in a training program which consisted of one-hour immersion at sevenmetres of depth breathing oxygen 100% with closed-circuit oxygen rebreathingapparatus. The training went on two or three times per week for the first six weeksand once a week for the last six weeks. Serum total antioxidant status (TAS), levels ofglutathione peroxidase (GPx), nitrates (NO3-) and urinary concentrations of 15-isoprostaneF2t were measured. The results show that TAS decreased significantly after6 weeks (mean 1.38 versus 1.23 mmol/l), with a slight increase at the end (mean 1.31mmol/l). GPx and F2-isoprostanes were significantly lower after 6 and 12 weeks andNO3- was significantly lower after 6 weeks and remained unchanged until the end.In summary, professional divers who use closed-circuit apparatus and thereforebreathe oxygen 100%, do not suffer an important oxidative hyperoxia-inducedstress, probably due an adaptive process after hyperoxia. The age and good physicalform of the subjects studied could probably enhance the adaptive process to hyperoxia(AU)

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Concentracion sérica de cobre ®libre¼ y ceruloplasmina en niños con desnutricion aguda grave antes de iniciar la terapia nutricional y al momento de recuperar el apetito en turbo, antioquia, colombia / Serum concentrations of free copper and ceruloplasmin in children with severe acute malnutrition before nutritional therapy and after children have recovered the apetite in turbo, antioquia, colombia

Introduction: copper supplementation therapy has been used in children with acute and severe malnutrition. Scientific evidence has shown that malnourished children with edema have free copper in plasma which could produce oxidative stress. Objective: To compared plasma concentrations of free copper between children with acute and severe malnutrition and a control group. Methodology: Cross sectional study where 66 normal and malnourished children were studied. A longitudinal study (before and after type) design was used including 40 children with severe and acute malnutrition; free copper was merasured by high-resolution capillary electrophoresis; ceruloplasmin and PCR by nephelometry. Results: In the cross sectional study children with marasmus had higher free copper serum concentrations than children with oedematous malnutrition, but the difference was not significant. In the control group this metal was not found. Children with oedema showed significant lower ceruloplasmin concentrations than children with marasmus (p=0.00) while the difference in PCR was also no significant for both groups. When the relationship between free copper serum concentrations and the presence of infection was analyzed no significant differences were obtained. However, serum albumin concentration was significantly lower for children with oedematous malnutrition than the marasmic group (p=0.016). After children recovered the appetite in the longitudinal study, serum free copper concentration decreased for both groups and ceruloplasmin concentration increased but no significant differences were observed. Conclusion: Copper supplementation could be considered as nutritional therapy for undernourished children since the beginning of the nutritional treatment, as it is recommended by WHO.

Introducción: La recuperación de los niños con desnutrición aguda grave incluye suplementación con cobre desde el inicio de la terapia; existen evidencias que niños edematosos pueden tener cobre libre en plasma el cual podría generar estrés oxidativo. Objetivo: Comparar concentraciones séricas de cobre libre y ceruloplasmina en un grupo de desnutridos agudos graves y un grupo control Metodología: estudio transversal al ingreso entre niños con y sin desnutrición en una muestra de 66 sujetos y longitudinal de tipo antes y después en 40 niños desnutridos. Se determinó cobre libre por electroforesis capilar de alta resolución; ceruloplasmina y PCR por nefelometría, además de variables clínicas Resultados: En el transversal, los marasmáticos presentaron niveles de cobre libre mayores que los edematosos sin diferencia significativa; en el grupo control este metal no se detectó. En los edematosos la concentración de ceruloplasmina fue significativamente menor con relación a los marasmáticos (p=0.00) y la PCR no presentó diferencia significativa entre ellos. No se encontraron diferencias significativas entre los niveles de cobre libre y presencia o no de infección. La albúmina se encontró más baja en los edematosos con diferencia significativa respecto a los marasmáticos (p=0.016). En el longitudinal, al recuperar el apetito el cobre libre disminuyó y la ceruloplasmina aumentó en los dos grupos sin diferencia significativa Conclusión: el suplemento de cobre como componente de la terapia nutricional puede ser suministrado a los desnutridos desde el inicio como lo propone el protocolo de la OMS.

Ejercicio aeróbico e hidrocinesiterapia en el síndrome fibromiálgico / Aerobic exercise and acuatic exercise in fibromyalgia syndrome

Objetivo. Revisar el efecto de la hidrocinesiterapia y del ejercicio aeróbico en pacientes con fibromialgia en la bibliografía consultada. Métodos. Se realizó una búsqueda en distintas bases de datos a partir del año 1977. Se encontraron 78 trabajos, de los cuales se seleccionó y accedió a 28. Conclusión. El ejercicio aeróbico y la hidrocinesiterapia mejoran el dolor, la rigidez, el dolor de los "tender points" y aumenta la calidad de vida y la capacidad aeróbica en pacientes con fibromialgia

Objective. Review the effect of acuatic and aerobic exercise on patients with fibromyalgia at the consulted bibliography. Methods. A search was made in some databases since year 1977. Seventy-eight articles were found, which from 28 were selected and accessed. Conclusion. Aerobic exercise an acuatic exercise improves pain, stiffness, pain of tender points, and increase the quality of life and aerobic ability on patients with fibromyalgia

Cellular composition of the adult rat anterior pituitary is influenced by the neonatal sex steroid environment.

Growth hormone (GH) and prolactin (PRL) secretion differ significantly between adult males and females and this is due, at least in part, to the postpubertal hormone environment which affects GH and PRL gene expression, as well as somatotrope and lactotrope proliferation. However, the role of the neonatal steroid environment in this phenomenon is less well understood. We have used in situ hybridization to determine the number of GH and PRL mRNA containing cells, as well as the level of expression of these two hormones and of the pituitary transcription factor 1 (Pit-1). Neonatally castrated male rats that had been exposed to testosterone during the neonatal period, adulthood or during both periods, males castrated as adults, normal adult males and normal proestrous females were used. Orchidectomy of adult rats had no effect on the number of somatotropes or lactotropes, but significantly reduced GH and PRL mRNA levels. Neonatal castration significantly reduced the percentage of somatotropes and increased that of lactotropes in the adult male. In addition, GH and Pit-1 mRNA levels were reduced significantly, but PRL mRNA levels were not modified. Treatment of neonatally castrated males with testosterone during the neonatal period significantly increased the percentage of somatotropes and decreased the percentage of lactotropes compared to vehicle-treated animals. It also increased GH and Pit-1 mRNA levels, but did not affect PRL mRNA levels. Adult testosterone treatment significantly increased the percentage of both somatotropes and lactotropes, as well as GH, PRL and Pit-1 mRNA levels. Treatment of neonatally castrated males with testosterone during both the neonatal and adult periods returned the percentage of somatotropes and lactotropes, as well as GH, PRL and Pit-1 mRNA levels, to that of the intact male. These results suggest that, although the postpubertal steroid environment is important in determining anterior pituitary hormone synthesis and cellular composition, the neonatal steroid environment also plays an important role in this phenomenon.

Differential effects of the neonatal and adult sex steroid environments on the organization and activation of hypothalamic growth hormone-releasing hormone and somatostatin neurons.

The secretory pattern of GH is markedly sexually dimorphic in the adult rat, a phenomenon that becomes manifest around the time of pubertal development. This event is due partially to the pubertal rise in gonadal steroids. However, the fetal and neonatal sex steroid environments also play an important role in generating this sexual dimorphism. Hypothalamic mRNA levels of GH-releasing hormone (GHRH) and somatostatin (SS), two neuropeptides implicated in the control of GH release, are sexually dimorphic in both neonatal and adult animals and, at least in the adult animal, are responsive to modulation by sex steroids. In this study, we examined the effects of neonatal testosterone on the number of GHRH and SS neurons in the adult hypothalamus as well as its effects on the responsivity of these neurons to later increases in sex steroids. To address these questions, male rats were either castrated or sham castrated on the day of birth (P0); these animals, along with intact females, received an injection of either testosterone or vehicle. At 60 days of age, half of each group received a Silastic capsule containing testosterone, and half received a sham implant. Growth rates were monitored throughout the study. At 75 days of age, animals were killed, and in situ hybridization to detect GHRH and SS mRNA containing neurons was performed. The number of GHRH neurons in the arcuate nucleus and ventromedial hypothalamus and the number of SS neurons in the periventricular nucleus and paraventricular nucleus were counted. Using a computerized image analysis system, GHRH and SS mRNA signal levels in individual neurons were also measured. Both neonatal and adult steroid treatments significantly increased growth rates. Those animals exposed to neonatal testosterone had significantly more detectable GHRH neurons than those that received only vehicle [P < 0.0001, by analysis of variance (ANOVA)]. Neonatal testosterone treatment had no effect on GHRH mRNA levels. Adult testosterone treatment, while having no effect on GHRH neuron numbers, stimulated GHRH mRNA levels in both males and females (P < 0.0001, ANOVA), but the magnitude of the increase depended upon whether the animal had been exposed to testosterone during the neonatal period. In contrast, the number of SS neurons was not affected by either steroid treatment. However, both treatments modulated SS mRNA levels (P < 0.0001, by ANOVA), with neonatal testosterone treatment alone resulting in significantly higher levels of SS mRNA in the adult animal. Adult testosterone treatment also significantly increased SS mRNA levels, and this was independent of previous exposure to sex steroids.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute nicotine administration increases somatostatin content and binding in the rat hypothalamus.

Within 4 minutes a single, intravenous injection of nicotine (0.3 mg/Kg) induced increases in somatostatin-like immunoreactivity concentrations in the rat hypothalamus but not in the striatum. These changes were associated with a significant increase in the specific binding of somatostatin to putative receptor sites in hypothalamic membranes, while no significant changes were found in striatum. The enhancement of somatostatin binding resulted from a rapid increase in the number of available receptors rather than a change in receptor affinity. This effect appears to be mediated by nicotinic cholinergic receptors, because pretreatment with a centrally active nicotinic receptor antagonist, mecamylamine (5.0 mg/Kg i.v.), prevented the nicotine-induced changes in somatostatin content and binding in the hypothalamus. Mecamylamine alone had no observable effect on the hypothalamic somatostatinergic system. These results suggest that the rat hypothalamic somatostatinergic system can be regulated by nicotine-like acetylcholine receptors.