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Biomedical subjects

J A Ortuño

Publications and source records attributed to J A Ortuño.

8 recordsLinked to original sources
PubMed2006

Differential pulse voltammetry and additive differential pulse voltammetry with solvent polymeric membrane ion sensors.

The ion transfer across the water-solvent polymeric membrane interface is investigated by using a new device based on a modification of a commercial ion-selective electrode body that permits the accommodation of a platinum counter electrode inside the inner filling solution compartment and, therefore, use of a four-electrode potentiostat with ohmic drop compensation. This device is used here to apply two different double potential pulse techniques--differential pulse voltammetry and additive differential pulse voltammetry--which are more advantageous than other voltammetric techniques, such as normal pulse voltammetry or cyclic voltammetry, for the determination of the characteristic electrochemical parameters of the system. This is due to the concurrence of two factors in these double potential pulse techniques, the peak-shaped response together with a considerable reduction of undesirable current contributions.

Ions↗
PubMed2002

Determination of zinc (II) in pharmaceuticals based on a flow-through bulk optode.

A method based on flow injection (FI), was applied for the determination of Zn (II) using a flow-through bulk optode membrane that incorporates 1-(2-pyridylazo)-2-naphthol in a plasticized poly (vinyl chloride) membrane entrapped in a cellulose support. The calibration graph plotting the reflectance at 562 nm versus [Zn (II)] was linear in the range 0.16-3.27 mgl(-1) (2.5 x 10(-6)-5 x 10(-5) M) with a detection limit of 0.10 mgl(-1). The variation coefficients of the sensor response for 0.33 mgl(-1) of Zn (II) were +/-0.11% for consecutive measurements (n=10), +/-0.19% between days (n=5) and +/-0.22% between different membranes (n=6). The sensor can be readily regenerated with the same acetic/acetate carrier of pH 3.9. The FI method proposed was applied to the determination of zinc (II) in pharmaceuticals.

Flow Injection Analysis↗
PubMed2001

Development of a new flow-through bulk optode for the determination of manganese(III).

A flow-through bulk optode based on the use of 1-(2-pyridylazo)-2-naphthol (PAN) immobilized in a plasticized poly(vinyl chloride) membrane entrapped in a cellulose support, in conjuntion with the flow injection analysis technique, is proposed for the determination of manganese(II). The calibration graph obtained at 570 nm was linear in the range 0.27-27.5 mg L(-1) (5 x 10(-6)-5 x 10(-4) M) Mn(II) with a detection limit of 0.18 mg L(-1). The coefficients of variation of the sensor response for 5.5 mg L(-1) of Mn(II) were +/-0.22% for consecutive measurements (n = 10), +/-0.48% between days (n = 5) and +/-0.38% between different membranes (n = 6). The sensor was readily regenerated with the carrier acetic acid/acetate buffer of pH 4.5. The method was applied to the determination of manganese in steels, waters and lemon tree leaves.

Journal Article↗
PubMed2000

A new procedure for the construction of flow-through optodes. Application to determination of copper (II).

A new procedure for constructing an optical fibre reflectance, bulk optode membrane type, sensor is presented. The optode membrane consists of a plasticized poly (vinyl chloride) membrane in which the ionophore is dissolved, entrapped in a cellulose support. The new optode with the dye indicator 1-(2-pyridylazo)-2-naphthol (PAN) was incorporated in a new flow-through cell and the injection system was optimized to determine Cu (II) at 567 nm in the range 5 x 10(-5)-10(-3) M. The response was reproducible and the optode can be regenerated using 10(-2) M EDTA followed by water. The method was applied to the determination of copper in real samples.

Journal Article↗
PubMed1995

[Do patients with duodenal ulcer transmit Helicobacter pylori to their relatives?].

The prevalence of IgG antibodies to Helicobacter pylori was determined with an enzyme-linked immunosorbent assay in 80 families who lived together with 40 duodenal ulcer patients in whom Helicobacter pylori had been cultured from a gastric biopsy (34 spouses, 31 children, 10 parents, 4 sisters and 1 brother) and in 112 controls from the same habitat and with similar age. The antibodies were positive in 38.4% of the relatives and in 36.6% of the controls, the difference was not significant. Among spouses of patients, 38.4% of those aged 25-39 years and 66.6% of those aged 40-67 years were positive, whereas controls showed a 29.2% and a 58.3% of positives respectively. The differences between both groups were not significant. Among children, 17.2% were positive and in parents 50%, whereas among controls with a similar age 26.3% and 62.5% respectively were positive. The differences between relatives and controls were not significant. We conclude that in our environment among consanguineous families living together and between spouses, person-to-person spread of Helicobacter pylori does not usually occur or it happens uncommonly.

Adolescent↗