PubMed Health⌕ Search

Biomedical subjects

J A Muñoz

Publications and source records attributed to J A Muñoz.

At least 19 recordsLinked to original sources
PubMed2006

Biosorption of heavy metals by activated sludge and their desorption characteristics.

The biosorption of different metals (Cu2+, Cd2+, Zn2+, Ni2+ and Pb2+) was investigated using activated sludge. The optimum pH was 4 for Cd, Cu and Pb sorption and 5 for Ni and Zn. Biomass metal uptake clearly competed with protons present in the aqueous medium, making pH an important variable in the process. Protons consumed by biomass in control tests versus protons exchange in biosorption tests confirmed a maximum exchange between metal cations and protons at pH 2. The study of the influence of biomass concentration revealed that the amount of protons released from biomass increased with biomass concentration. This would confirm the hypothesis of ion exchange between both types of ions. The application of the Langmuir and Freundlich models showed a better fitting of experimental data to the first model. The maximum sorption uptake of the studied metals by the activated sludge showed the following decreasing order: Pb>Cu>CdZn>Ni. Desorption experiments showed that HCl was a good eluent for the five metals tested, particularly at low pH values (1 and 2). At pH 3 or 4 the desorption yield was significantly lower. However, its use did not allow the reuse of biomass in subsequent loading and unloading cycles. EDTA was also a good desorption agent, achieving the total recovery for the five metals tested at a concentration of 1mM, with the advantage that biomass could be reused for three sorption-desorption cycles.

Adsorption↗
PubMed2006

Influence of concomitant food intake on the excretion of orally administered myo-inositol hexaphosphate in humans.

myo-Inositol hexaphosphate (InsP6) widely occurs in plant seeds. At present, some important benefits of InsP6 for human health have been described. The purpose of this study was to find the best condition for the optimum absorption of orally administered InsP6, evaluated by InsP6 urinary excretion. The influence of different stomach conditions (empty, empty with an alkalinizing agent, and full stomach) on the effects of oral administration of InsP6 and its urinary excretion was investigated in six healthy subjects on an InsP6-poor diet, given 400 mg of calcium/magnesium salt of InsP6 as a single dose. The basal urinary excretion of InsP6 on an InsP6-poor diet (50.91 +/- 15.09 microg) was significantly lower than that found when an InsP6-normal diet was consumed (100.09 +/- 26.42 microg) (P < .05). No differences were observed in the areas under the curve of accumulated excretion at 8 hours among the three different stomach conditions studied, suggesting that the overall InsP6 absorption took place independently of the stomach state (full or fasted) and indicating that the InsP6 absorption also takes place during the intestinal transit. Thus, if InsP6 supplements of vegetal origin are consumed to maintain the optimum InsP6 levels needed for a healthy status, these supplements can be consumed either during or between meals with the same efficacy.

Absorption↗
PubMed2005

Gold and silver uptake and nanoprecipitation on calcium alginate beads.

Calcium alginate beads were investigated for their biosorption performance in the removal of gold and silver from aqueous solutions. It was found that uptake capacities were significantly affected by the solution pH, with optimum pH values of 2 and 4 for gold and silver, respectively. Kinetic and isotherm experiments were carried out at the optimum pH. The maximum uptake capacities were 290 mg/g for Au and 52 mg/g for Ag. FTIR analysis indicated that both carboxylic and hydroxylic functional groups in alginate beads are involved in the metal binding and later reduction of gold (+3) and silver (+1) to gold (0) and silver (0). SEM and X-ray diffraction confirmed the formation of gold and silver nanoparticles.

Adsorption↗
PubMed2005

Effects of trace metals on the inhibition of calcium oxalate crystallization.

The aim of this study was to examine the possible effects of some trace metals on the inhibition of calcium oxalate crystallization. A test of urinary lithogenic risk was used to follow the crystallization of calcium oxalate from artificial urine in the presence of several metal ions assayed in their physiological concentrations. Interactions of these metal ions with known inhibitors of such crystallization (phytate, pyrophosphate, citrate and chondroitin sulphate) were also investigated. None of the metals affected the inhibition of calcium oxalate crystallization at concentrations approximating those found in normal urine, with the exception of the Fe3+ ions. Interactions of Fe3+ with some urinary components produced both synergic (phytate and pyrophosphate) and negative (citrate) effects on preventing crystallization. These effects are explained in terms of the affinity of the inhibitors for the calcium oxalate crystal surface and their ability to form stable complexes in urine. Because of the minimal concentrations, we conclude that physiological concentrations of trace elements in urine have no significant influence on calcium oxalate crystallization. In this sense, ferric ions, which exhibit an intrinsic high inhibitory capacity of calcium oxalate crystallization at physiological concentrations, even increased by the concomitant presence of phytate and pyrophosphate, are probably unable to act as powerful inhibitors in the presence of physiological urinary concentrations of citrate, due to the formation of highly stable complexes in solution without inhibitory activity.

Calcium Oxalate↗
PubMed2004

[Metabolic imaging by positron emission tomography using [18F] fluorodeoxiglucose in developmental disorders].

INTRODUCTION: Developmental disorders are a common pathological condition in Neuropaediatrics and do not usually present characteristic anatomical alterations in the different neuroanatomical imaging tests that can be employed, such as computerised axial tomography or magnetic resonance (MR). Positron emission tomography (PET) using [18F] fluorodeoxiglucose (PET FDG), one of the battery of imaging tests currently available, enables us to obtain data about brain activity in a non invasive manner. PATIENTS AND METHODS: A group of 39 patients with developmental disorders from the Hospital del Mar was analysed. They were submitted to PET FDG brain metabolism tests and in some cases hybrid PET MR images were also obtained; findings were then correlated against the clinical progression of the patients. RESULTS AND CONCLUSIONS: The alterations that were observed showed predominantly bilateral thalamic, mesial temporal and orbital frontal hypometabolism. This alteration of the limbic system, which has no correlation with anatomical damage, can be a predictor of the clinical progression and of the confirmation of the presence of alterations in the brain functions in this type of patients.

Brain↗
PubMed2001

Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria.

This study evaluates different bioleaching treatments of a molybdenite concentrate using mesophilic and thermophilic bacterial cultures. Further studies on the chemical leaching and the electrochemical behavior of the MoS(2) concentrate were carried out. Bioleaching tests showed a progressive removal of chalcopyrite from the molybdenite concentrate with an increase in temperature. Chemical leaching tests support the idea of an indirect attack of the concentrate. Electrochemical tests indicate that chalcopyrite dissolution is favored when molybdenite is present. Therefore, this type of bioleaching treatment could be applied to purify molybdenite flotation concentrates by selectively dissolving chalcopyrite.

Bacteria↗
PubMed2001

Growth of moderately halophilic bacteria isolated from sea water using phenol as the sole carbon source.

Moderately halophilic bacteria utilizing phenol as the sole carbon source were isolated by selective enrichment from sea water. The isolate (Gram-negative motile rods) was identified as Deleya venusta. It grew well in the presence of up to 1600 mg/L of phenol and 8% NaCl under aerobic conditions. When the cells were treated with chloramphenicol prior to the addition of phenol they did not utilize added phenol, even after prolonged incubation. Thus, the enzymes necessary for phenol metabolism appeared to be inducible.

Arthrobacter↗
PubMed2000

Effect of electron beam irradiation on color and microbial bioburden of red paprika.

The effect of irradiation with electron beams on the microbiological quality and color properties of red paprika was examined. The irradiation doses ranged from 0 to 12.5 kGy. The counts performed were total mesophilic aerobic microorganisms, Enterobacteriaceae, coliforms, sulfite-reducing clostridia, molds, and yeasts. It was concluded that molds, yeasts, and sulfite-reducing clostridia were the most resistant species, although a 10-kGy dose of irradiation leads to optimum sanitation. Extractable color and apparent color were analyzed to appraise the incidence of the irradiation treatments in the color properties of red paprika. Extractable color was determined according to the American Spice Trade Association method, and apparent color was analyzed by reflectance using the CIELab color space. Data showed no significant differences between the color properties of irradiated and nonirradiated samples. Irradiation was a suitable procedure to minimize the bioburden of red paprika with small modifications of its color properties.

Capsicum↗
PubMed1998

MsPG3, a Medicago sativa polygalacturonase gene expressed during the alfalfa-Rhizobium meliloti interaction.

Polygalacturonase (PG) is one of the most important enzymes associated with plant cell wall degradation. It has been proposed to participate in the early steps of the Rhizobium-legume interaction. We have identified two classes of cDNA fragments corresponding to two classes of PG genes in the Medicago genome. One of this class, represented by E2 in M. truncatula and Pl1 in M. sativa, seems to be related to previously characterized plant PG genes expressed in pollen. We have isolated the genomic clone containing the entire gene corresponding to the second class (E3). We showed that MsPG3 is a single gene in the Medicago genome coding for PG. By reverse transcription-PCR, MsPG3 expression was detected in roots 1 day after Rhizobium inoculation. The early induction of the MsPG3, as also seen by in situ hybridization experiments, supports its involvement in the early stages of the Rhizobium-legume infection process. In addition, by analyzing the expression of a MsPG3 promoter-gus construct in Vicia hirsuta-transgenic root nodules, we showed that MsPG3 was expressed in all cells of nodule primordia and in the cells of the invasion zone. By Northern blot, MsPG3 transcripts are not detected in various Medicago tissues, indicating that the function of this gene is related closely to symbiosis. Thus, our results strongly suggest the involvement of MsPG3 gene during meristem formation and/or in the infection process, probably by facilitating cell wall rearrangement, penetration of the bacteria through the root hair wall, or infection thread formation and release of bacteria in plant cells. MsPG3 represents a class of PG genes, distinct from the pollen-specific genes, and it is the first pectic encoded enzyme demonstrated to be involved in Rhizobium-legume symbiosis.

Amino Acid Sequence↗
PubMed1998

[Iron deficiency and pica].

PURPOSE: To study the relationship between pica and iron-lack anaemia in a series of iron-deficiency patients in order to establish the pathogenesis of such relationship. PATIENTS AND METHODS: Four-hundred and thirty-three patients were analysed. Pica was studied by introducing certain diet queries into the clinical history. All patients received oral iron and were periodically controlled with the usual clinico-haematological procedures. RESULTS: Pica was present in 23 patients (5.3%). Eight nourishing (namely, coffee grains, almonds, chocolate, ice, lettuce, carrots, sunflower seeds and bread) and 2 non-nourishing (clay and paper) substances were involved. A second episode of pica appeared in 9 cases upon relapsing of iron deficiency. Both anaemia and pica were cured by etiologic and substitutive therapy in all instances. No clear correlation was found with either socio-economic status or pathogenetic causes of iron deficiency and pica, and no haematological differences were seen between patients with pica and those without this alteration. CONCLUSIONS: (1) The pathogenesis of pica is unclear, although it appears unrelated to the degree of iron deficiency. (2) According to the findings in this series, pica seems a consequence of iron deficiency rather than its cause. (3) Adequate therapy can cure both conditions, although pica may reappear upon relapse of iron deficiency.

Adolescent↗
PubMed1998

Red blood cell phenotypes in alpha-thalassemias in the Spanish population.

BACKGROUND AND OBJECTIVE: alpha-thalassemia is very common on all thalassemic geographical regions. The present work aimed at analyzing the relationship between the degree of microcytosis and hematological parameters and the type of alpha-thalassemic mutation. DESIGN AND METHODS: Five hundred and thirty-six subjects with 4 kinds of alpha-thalassemia were examined using established techniques that determined all hematological parameters, and globin synthesis and molecular biological techniques to study the DNA of globin genes by Southern blotting. RESULTS: Adult carriers of alpha (+)-thalassemia (-alpha/alpha alpha) present very few hematological alterations. In a statistical comparison with normal individuals (alpha alpha/alpha alpha), significant differences were found between the hemocytometric data and the MCV and MCH of heterozygous alpha + thalassemia and the heterozygous alpha zero or homozygous alpha + genotype. Hb H disease was detected in 15 patients, presenting a severe degree of anemia, a significant increase in RDW and globin chain synthesis with an alpha/beta ratio of 0.5 +/- 0.1. INTERPRETATION AND CONCLUSIONS: These data provide reference values for geographical areas where alpha + thalassemia is common. These hematocytometric data, together with hemoglobin analysis, could be useful as a future reference data for new patients diagnosed with alpha-thalassemia.

Adolescent↗
PubMed1997

[Association of alpha and beta thalassemia with alpha gene triplication in one family].

UNLABELLED: We describe the haematological data and molecular results of a native family from Cádiz in that one is produced the a within heterozygous beta 0 thalassaemia (IVS-1, nt 1-G-->A), heterozygous alpha+ thalassaemia (-alpha 3.7) and alpha gene triplication (alpha alpha alpha 3.7). PATIENTS AND METHODS) We are studied 7 members to a family composed by father (I1), mother (I2) and five children (II1, II2, II3, II4, II5). The molecular biology study of the alpha gene was realized by Southern blot method using the restriction enzymes Bam HI, Bgl II and Eco RI and hybridized with alpha probe of the plasmid PRB 1 (fragment of 1.5 Kb digested with the enzyme Pst I). The genes were studied by the technique of the polymerase chain reaction (PCR), modified according to designated method "Amplification Refractory Mutation System" (ARMS). RESULTS: The father (I1) presents an interaction of therozygous beta 0 thalassaemia with heterozygous alpha + thalassaemia (beta 0/beta 1;alpha alpha/-alpha 3). The mother (I2) shows an alpha gene triplication (beta A/beta A: alpha alpha alpha 3.7/alpha alpha). Finally the children are expressed 5 possibilities: II4 he is normal (beta A/beta A; alpha alpha/alpha alpha), II2 he has alpha gene triplication (beta A/beta A; alpha alpha/alpha alpha alpha 3.7), II3 he has heterozygous beta 0 thalassaemia (beta 0/beta A; alpha alpha/alpha alpha), II5 he has interaction between heterozygous beta 0 thalassaemia and heterozygous alpha gene triplication (beta 0/beta A; alpha alpha alpha 3.7/alpha alpha) and II1 presents an interaction between a heterozygous beta 0 thalassaemia and together with the lost of one alpha gene in one chromosome he also presents a alpha gene triplication in other one (beta o/beta A; alpha alpha/alpha alpha). The hematological data of II5 corresponds to a intermediate thalassemia with not transfusion dependent feature an opposite to II1 that presents a heterozygous thalassemic trait features with 4 alpha genes. DISCUSSION: The phenotypical expression of the different interactions of these mutations in this family, points out, the relevant role that the unbalance globins chains plays in the pathogenesis and development of the clinical manifestations of the patients with the thalassaemia syndromes.

Adolescent↗
PubMed1996

[Effects of several methods of thoracic drainage on respiratory function].

UNLABELLED: The object of this study was to verify the influence on the pulmonary function of the pleural space ampliation with pleural drainage tube underwater seal, with several volumes or with variables negative pressures. We performed 42 New Zealand white rabbits of both sexes with an average age of 57 +/- 9.31 days and an average weight of 1720 +/- 181 g. The experimental protocol consisted of study group: P1 (n = 14) was performed a unilateral thoracostomy at the 5th. Intercostal space and P2 (n = 14) with bilateral pleural drainage. The pleural drainage tube (drain trocart ORX Vygon number 8) connected at small bottle (Fp), with 35 ml of extrapleural volume and at big bottle (FG) with 3940 ml of extrapleural volume and vacuum suction of various negative pressures (-5, -10, -15 and -20 cm H2O). CONTROL GROUP: C1 (n = 7) with unilateral pleural drainage clamped and C2 (n = 7) with bilateral pleural drainage clamped. Anesthesia was induced with ketamine hydrochloride (7.5 ml/Kg) and propionilpromazyne (1.5 ml/Kg) intramuscular cocktail and after maintained with bolus injection of 1/4 induction dose. We studied the mortality, the the fluctuations of drain hydrostatic column, heart rate (FC), respiratory rate (FR) and blood gas tensions, after cannulation of right jugular vein and during the different phases of experimental design. Venous blood samples were obtained for pO2, pCO2 and pH measurements were repeated at 5' in both groups. The 50% of animals died in the P2 group during the drainage pleural of FG. The fluctuation of column of Fp was similar in both groups: P1 = 6.39 +/- 1.0, with a decrease of 0.64 +/- 0.23 and P2 = 6.37 +/- 1.29, with a decrease of 0.63 +/- 0.28, respectively. The vacuum suction of pleural cavity may produce a FR fall which recovery fast. The bilateral pleural drainage with negative pressures produced decreases of pCO2 and pO2. There is not modifications of Acid Base Balance in the experimental groups. We concluded that during bilateral pleural underwater seal connected a FG, because the increase of extrapleural space may produce a high mortality and a fall of respiratory rate with fast recovery. Also the pleural suction improved the CO2 diffusion into the alveolus. There is not modifications of pO2 in P1 group or decrease in the P2 group.

Animals↗