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Biomedical subjects

M Zubillaga

Publications and source records attributed to M Zubillaga.

At least 19 recordsLinked to original sources
PubMed2006

Iron bioavailability from fortified fluid milk and petit suisse cheese determined by the prophylactic-preventive method.

In this research, we measure the iron bioavailability of micronized ferric orthophosphate when it is used to fortify low-fat fluid milk enriched with calcium and petit suisse cheese using the prophylactic-preventive method in rats. Four groups of male weaned rats received a basal diet (control diet; 6.5 ppm Fe), a reference standard diet (SO4Fe; 18.2 ppm Fe), a basal diet using iron-fortified fluid milk as the iron source (milk diet; Fe ppm 17.9), and a basal diet using iron-fortified petit suisse cheese as the iron source (cheese diet; 18.0 ppm Fe) for 22 d. The iron bioavailability of the different sources was calculated as the ratio between the mass of iron incorporated into hemoglobin during the experiment and the total iron intake per animal. The relative biological values with regard to the reference standard (RBV%) were 61% and 69% for the milk and cheese diet, respectively. These results show that according to this method, the iron bioavailability in both fortified foods can be considered as medium bioavailability rates.

Animals↗
PubMed2006

Dietary zinc effects on zinc, calcium, and magnesium content in bones of growing rats.

The aim of the present study was to assess dietary zinc effects on femur weight and mineral content in growing rats. For this purpose, 70 weanling Sprague-Dawley rats were divided into four groups. Each group was subject to a diet containing 2 (BZ), 5 (DZ), 10 (MZ), and 30 (CZ) ppm zinc. The calcium and magnesium content in all diets was 5 g/kg and 507 mg/kg, respectively. The animals were kept on this regime for 28 d and then sacrificed and their femurs were removed for analysis using atomic absorption spectrophotometry. The weights of the BZ and DZ groups were significantly different from the MZ and CZ groups (38.5+/-10.5, 89.9+/-13.7, 118.6+/-13.6, and 134+/-19.9 g, p<0.01) respectively. There were no differences between the MZ and CZ groups. Femur weight also varied with dietary zinc, as it was significantly different among all groups (BZ, 265+/-49 mg; DZ, 380+/-40 mg; MZ, 452+/-54 mg; CZ, 735+/-66 mg; p<0.01). The femur zinc content varied with diets, following a different pattern than the above parameters. Femur zinc from the BZ group (51.5+/-5.4 ppm) was significantly different from the MZ and CZ groups (115.9+/-14.2 and 175.0+/-13.5 ppm, respectively), whereas the DZ group (62.5+/-11.3 ppm) did not differ from the other three groups. The femur content of calcium (BZ, 83.2+/-9.8 mg/g; DZ, 88.0+/-9.2 mg/g; MZ, 90.2+/-13.6 mg/g; CZ, 83.1+/-14.7 mg/g) and magnesium (BZ, 1.82+/-0.13 mg/g; DZ, 1.98+/-0.09 mg/g; MZ, 1.93+/-14 mg/g; CZ, 1.83+/-0.19 mg/g) were not significantly different among the groups, nor was the calcium-magnesium ratio. These results suggest that although dietary zinc deficiency retards growth and causes bone fragility, bone deposition of calcium and magnesium and its ratio are not affected.

Animals↗
PubMed2005

In vivo iron and zinc deficiency diminished T- and B-selective mitogen stimulation of murine lymphoid cells through protein kinase C-mediated mechanism.

Zinc and iron are crucial mineral components of human diet, because their deficiency leads to several disorders, including alterations of the immune function. It has been demonstrated, in both humans and rodents, that a diminished number of lymphoid cells and a loss of lymphocyte activity accompany deprivation of these essential minerals. The aim of this work was to analyze if iron and/or zinc imbalances regulate lymphocyte activity and the intracellular signals involved in the effect. Mice from the BALB/c strain were fed with iron- and/or zinc-deficient or mineral-supplemented diets, according to the American Institute of Nutrition Rodent Diets. Levels of iron and zinc were assessed in blood, liver, or bone samples. Selective mitogen stimulation of T- and B-lymphocytes were performed. We found a diminished proliferative response in T- and B-lymphocytes from zinc- and/or iron-deficient animals with respect to controls. These effects were related to decreased mitogen-induced translocation of protein kinase C (PKC) activity to cell membranes on both cell types from all animals fed with deficient diets. Our results demonstrate that iron and zinc deficiencies affect both T- and B-lymphocyte function by PKC-dependent mechanisms.

Animals↗
PubMed2005

Determination of relative bioavailability of zinc in a petit suisse cheese using weight gain and bone zinc content in rats as markers.

The aim of the study was to determine the relative bioavailability of zinc gluconate stabilized with glycine in a Petit Suisse cheese from an infant dessert. Weight gain and bone zinc content were the nutritional responses evaluated for the diets of different zinc content: 2 ppm (basal) and 5, 10, and 30 ppm from zinc gluconate stabilized with glycine and zinc sulfate. Nonlinear regression analysis of the fitted curves for weight gain determined a relative zinc bioavailability of 100% for the Y max ratio and 96% for Ymax/t1/2 ratio for zinc gluconate stabilized with glycine (R2=0.7996 for zinc sulfate and 0.8665 for zinc gluconate stabilized with glycine). The slope ratio analysis from linear regression of femur zinc determined a relative zinc bioavailability of 93% for zinc gluconate stabilized with glycine (R 2=0.8693 for zinc sulfate and 0.8307 for zinc gluconate stabilized with glycine). Zinc gluconate stabilized with glycine has similar bioavailability as zinc sulfate in a Petit Suisse cheese nutritional matrix, with the advantage that the stabilized compound does not modify the sensorial characteristics of the fortified cheese.

Animals↗
PubMed2005

Normal growth rate in rats is recovered after a period of zinc deficiency by restoration of zinc supply by means of a zinc-fortified Petit Suisse cheese.

Fortification of a Petit Suisse cheese with zinc sulfate and zinc gluconate stabilized with glycine was used as a tool to overcome zinc-deficiency effects on total-body growth and skeletal growth. Animals were divided in 4 groups of 10 rats: basal (B), control (C), depletion-repletion 1 (DR1), and depletion-repletion 2 (DR2). These four groups were fed with four diets: basal (2 ppm Zn), control (30 ppm Zn), DR1, and DR2; they received a basal diet for 14 d and a control diet for the other 14 d of the experiment, using zinc sulfate for DR1 and zinc gluconate stabilized with glycine for DR2. After 28 d of the experiment, total-body weight and weight gain of the control and DR1 and DR2 animals were not statistically different (p<0.05), Femur weight and femur zinc content of DR1 and DR2 did not achieve the values of control animals (p<0.05), but they were higher than that of basal animals. Our results show that restoration of dietary zinc levels by means of food fortification normalized weight gain, as an indicator of total-body growth, and presented a trend to normalize bone weight, as a marker of skeletal growth, in young rats and independently of the zinc source used.

Animals↗
PubMed2005

Nutritional and technological behavior of stabilized iron-gluconate in wheat flour.

Food fortification has been shown to be an effective strategy to overcome iron malnutrition. When a new iron compound is developed for this purpose, it must be evaluated from a nutritional and technological point of view before adding it into foods. In this way, we have evaluated ferrous gluconate stabilized by glycine as a new iron source to be used in wheat flour fortification. We performed biological studies in rats as well as sensory perceptions by human subjects in wheat flour fortified with this iron source. The productions of pentane as a rancidity indicator as well as the change of the sensorial properties of the biscuits made with stabilized ferrous gluconate-fortified wheat flour were negligible. Iron absorption in water from this iron source was similar to the reference standard ferrous sulfate. Nevertheless, because of the phytic acid content, iron absorption from fortified wheat flour decrease 40% for both iron sources. The addition of zinc from different sources did not modify iron absorption from ferrous sulfate and stabilized ferrous gluconate in water and wheat flour. The iron absorption mechanism as well as the biodistribution studies demonstrate that the biological behavior of this iron source does not differ significantly from the reference standard. These results demonstrate that the iron source under study has adequate properties to be used in wheat flour fortification. Nevertheless, more research is needed before considering this iron source for its massive use in food fortification.

Animals↗
PubMed2004

Review article: is there a link between micronutrient malnutrition and Helicobacter pylori infection?

Helicobacter pylori causes a chronic gastric infection, which is usually life-long. Many epidemiological studies have shown that this is probably one of the most common bacterial infections throughout the world involving 30% of the population living in developed countries and up to 80-90% of the population in developing regions. Concomitantly, developing regions also have high prevalence of micronutrient malnutrition. In the last few years, some studies have suggested that H. pylori infection may affect the homeostasis of different micronutrients including iron, vitamin B12, folic acid, alpha-tocopherol, vitamin C and beta-carotene. In this article, we discuss the current scientific information of the effect that H. pylori infection may produce on micronutrient malnutrition.

Helicobacter Infections↗
PubMed2004

Zinc deficiency and growth: current concepts in relationship to two important points: intellectual and sexual development.

Zinc deficiency remains a serious health problem worldwide affecting developed as well as developing countries. Despite the evidence proving that zinc deprivation during the periods of rapid growth negatively affects the cognitive brain as well as sexual development, there are few complete studies carried out in children. The present article proposes a revision of the evidence gathered until now on the relationship existing between zinc deficiency and intellectual and sexual development during the stages of childhood, preadolescence, and adolescence.

Animals↗
PubMed2004

The usefulness of stable isotopes in nutrition and human health: the application of mass spectrometry and 13C-breath tests to detect helicobacter pylori infection.

The interest in Helicobacter pylori has escalated in recent years. H. pylori may produce a chronic gastric infection which is usually life-long and many epidemiological studies have shown that this is the most common bacterial infection throughout the world involving 50% of the world population. Thus, it is clear that the diagnosis of H. pylori infection represents at least a key step in the management of many of the patients referred to the gastroenterologist. Additionally, due to the wide range and relevance of pathologies possibly related to this infection, from micronutrient malnutrition and co-infections to malignancies, there is the potential for H. pylori to be a major health problem. Improved methods for the diagnosis and follow up treatment of the infection have been developed. Use of stable isotopes as non-invasive and safe diagnostic methods, namely (13C) breath tests, has been the key to a new era of research in H. pylori epidemiology and diagnosis as well as the establishment of eradication therapies. This non-invasive nuclear technique, that is considered the gold standard for the diagnosis of this bacterial infection, has successfully been standardized and implemented along Latin America. Taking into account the high prevalence of this bacterial infection, the impact of this technique in the whole region is very high. In this article we discuss several aspects of this methodology in order to harmonize the application of this method in developing regions.

Breath Tests↗
PubMed2001

Bioavailability studies of a new iron source by means of the prophylactic-preventive method in rats.

The bioavailability of iron from a new commercial source containing ferric gluconate stabilized with glycine sold under the trade name Bioferrico was studied in this work by means of the prophylactic-preventive test in rats. NaFeEDTA was also studied by the same methodology for comparative purposes and ferrous sulfate was used as the reference standard. The test was conducted for 4 wk with male weaned rats, which were randomized into four groups of at least eight animals each. A control group received a basal diet of low-iron content, whereas the other groups received the same diet with iron added at a dose of 20 mg/kg as FeSO4.7H2O, NaFeEDTA, and Bioferrico, respectively. Individual hemoglobin concentrations (HbC) and weights were determined at the beginning and at the end of the study and food intake was daily registered. The iron bioavailability (BioFe) of each source was calculated as the ratio between the amount of iron incorporated into hemoglobin during the treatment (HbFe) and the total iron intake per animal (ToFeIn). A relative biological value (RBV) was obtained for each iron source under study as the ratio between the BioFe of the tested compound and that of the reference standard. The RBVs were 98% and 86% for Bioferrico and NaFeEDTA, respectively. Bioferrico showed a high bioavailability and behaved inertly in relation to the sensorial properties of the fortified food when it was added to flour. These qualities emphasize Bioferrico as a promising source for iron fortification.

Animals↗
PubMed2000

99mTc-ENS ventilation scintigraphy: preliminary study in human volunteers.

Exogenous natural surfactant (ENS) labeled with (99m)Tc ((99m)Tc-ENS, 900-1110 MBq), a new radiopharmaceutical for ventilation scintigraphy, was nebulized during 3 min to five volunteers. For comparative purposes, (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) was studied in the same way. (99m)Tc-ENS images were of at least the same quality as (99m)Tc-DTPA images. However, in smoking volunteers, the (99m)Tc-DTPA images show some areas that seemed to be not well-ventilated, although these areas appeared well-ventilated when the study was performed with (99m)Tc-ENS. These results suggest that (99m)Tc-ENS can be used for ventilation scintigraphy to allow the observation of some areas that cannot been visualized using (99m)Tc-DTPA as ventilation agent.

Adult↗
PubMed2000

Zinc status and immune system relationship: a review.

The essentiality of zinc for humans was first documented by Prasad in the 1960s. The main clinical manifestations associated with zinc deficiency are growth retardation, hypogonadism, diarrhea, and increased susceptibility to infectious diseases. Thus, in the past 25 yr, there was an increased interest of researchers in studying the role of zinc in human immunity. Although mechanistic research has been carried out using animal models, there are several studies in humans with similar results. This work is an attempt to review the information available in this field to understand the important role that zinc plays in the normal development and function of the immune system.

Aged↗
PubMed1999

[Zinc: concepts on an essential micronutrient].

It is now well known that zinc is an essential micronutrient. Even though much information is available, there are many points that remain to be studied. zinc is absorbed by the intestine and transported in the plasma by albumin, forming a small exchangeable pool, which is rapidly exhausted even in cases of mild deficiency. zinc is essential for the activity of about 70 enzymes among other functions. Therefore, zinc deficiency produces a great number of clinical disorders, the symptoms of which may range between mild up to serious dysfunctions. These problems are corrected by a dietary supplementation with zinc. The lack of a reliable method to determine the zinc nutritional status reflects the problem to estimate the metal recommended dietary allowances, which are difficulty met specially by children, old persons and pregnant women which constitute the main risk groups. Although our knowledge concerning zinc toxicity is scarce, it is well known that the amounts of zinc that produces toxic effects are much higher than those that are contained in regular diets as well as in diets supplemented with this metal. Therefore, the need of the development of effective strategies, like food fortification with proper zinc compounds, appears as an attractive alternative in order to prevent and/or correct the deficiency of this vital element and to improve the health and the life quality of the whole population.

Age Factors↗
PubMed1999

Stable isotope techniques for the detection of Helicobacter pylori infection in clinical practice. 13C-Urea Breath Test in different experimental conditions.

The 13C-UBT has been demonstrated to be a reliable method for the evaluation of Helicobacter pylori infection. The aim of our work is to determine the cut-off point of the 13C-UBT for samples collected as gas or collected in a solution of triethanolamine. For this purpose, patients fasted for at least 6 hours were able to collect basal samples before the administration of 65 mg of 13C-urea solution. Breath samples were taken 10, 30 and 60 minutes after the administration of the labeled solution. All the samples were collected in gas collectors and in glass vials containing 1 ml of a 7% triethanolamine solution. The cut-off points for gas collected samples were established in 4.0/1000, 4.6/1000 and 4.4/1000 for 10, 30 and 60 minutes samples, respectively, while for the samples collected in triethanolamine solution, cut-off points were established in 5.0/1000, for the 10 minutes samples, in 3.5/1000 for the 30 minutes samples and 4.7/1000 for the 60 minutes samples. We found that this test has a sensitivity of 100% and a specificity of 100% for H. pylori detection in both experimental conditions, when multiple breath samples are taken. If we considered only the 30 minutes time, sensitivity and specificity diminish for the gas collected samples. We conclude that the collection of breath samples in triethanolamine solution allows a better differentiation between H. pylori infected and non infected patients than gas collected samples.

Analysis of Variance↗
PubMed1998

[The pulmonary surfactant system: physiology, pathologies associated with its alteration and exogenous administration as therapeutic and diagnostic agent].

Pulmonary surfactant is a lipoproteic mixture synthesized and secreted by alveolar type II cells. Its principal property is to reduce the surface tension by lining on the alveolar surface. Surfactant deficiency is the major factor responsible for the respiratory distress syndrome of the newborn (RDS) and the adult respiratory distress syndrome (ARDS). Since 1980, the exogenous administration of surfactant for the treatment of these syndromes is being studied. In this work the exogenous surfactant preparations, the delivery techniques and the dosing schedule is discussed. The utilization of the exogenous natural surfactant (ENS) as precursor of a radiopharmaceutical labeled with 99mTc (99mTc-ENS) for aerial lung scintigraphy is also discussed.

Adult↗
PubMed1997

MIN 14C UBT: a combination of gastric basal transit and 14C-urea breath test for the detection of Helicobacter pylori infection in human beings.

The purpose of this work is to demonstrate that the 14C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14C UBT, is a modification of the conventional 14C UBT in which low volumes of a solution of 14C-urea together with 99mTc-sulfur colloid are administered. The 99mTc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the "visualization" of the transit of the 14C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14CO2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection.

Breath Tests↗
PubMed1997

[Brachytherapy of solid tumors. Use of chromic phosphate colloid].

With the purpose of studying the effectivity of an intratumoral single dose of chromic [32P] phosphate (Phosphocol) for the treatment of solid tumors, studies of bioelimination, biodistribution and therapeutic action were carried out in rats with experimental induced tumors. The results show that the percentage of total elimination is equal to 29.76 +/- 9.60% with a higher percentage in faeces 23.28 +/- 8.81% than in urine 6.48 +/- 2.11%. Biodistribution studies show that, 51.61 +/- 5.82% of the injected activity is found in the tumor while in organs with reticuloendothelial cells, the percentage of activity was 13.09 +/- 5.15% in liver and 2.88 +/- 1.23% in lung. On the other hand, when therapeutic action was evaluated, we found that the percentage of tumor regression (P.T.R) was 61.0% for the injected tumors. It is important to point out that 4 of the treated animals show bioelimination patterns in which the elimination rises suddenly at some time of the study. These results demonstrate that the use of this kind of colloids is not to be recommended for the treatment of solid tumors with moderated degree of vascularization, since its mobilization from the injection point may result in the consequent irradiation of different organs that are not under treatment.

Adenocarcinoma↗