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Biomedical subjects

A Sanz

Publications and source records attributed to A Sanz.

At least 37 records · Page 2Linked to original sources
PubMed2001

Determination of riboflavin, flavin mononucletide and flavin adenine dinucleotide in biological tissues by capillary zone electrophoresis and laser-induced fluorescence detection.

The separation of riboflavin, flavin mononucleotide and flavin adenine dinucleotide was investigated by capillary zone electrophoresis using laser-induced fluorescence detection. In the systematic approach developed, the differential electrophoretic mobilities were first maximized by adjusting the pH. Increasing the buffer concentration improved the separation at the expense of migration times. A buffer consisting of 50 mM phosphate adjusted to pH 8.5 was found to provide a very efficient and stable electrophoretic system. Responses were linear within the range 0.1-100 micromol L(-1), and the detection limits of B2 vitamers were 0.23 nmol L(-1) or less. The method was successfully applied to a variety of biological tissues from different animals.

Calibration↗
PubMed2001

Simultaneous determination of doxorubicin, daunorubicin, and idarubicin by capillary electrophoresis with laser-induced fluorescence detection.

The separation and simultaneous determination of doxorubicin, daunorubicin and idarubicin was investigated using capillary electrophoresis with laser-induced fluorescence detection. Because the three anthracycline antibiotics were similar in structure and mass, careful manipulation of the electroosmotic flow and electrophoretic mobilities was required. A buffer consisting of 100 mM borate, adjusted to pH 9.5, containing 30% acetonitrile was found to provide a very efficient and stable electrophoretic system for the analysis of the three anthracyclines. The method was applied to the determination of three anthracyclines in serum samples. Responses were linear in the range of 10-500 ng.mL-1 and the detection limits were lower than 0.9 ng.mL-1.

Antibiotics, Antineoplastic↗
PubMed2001

The role of perceived control in physiological reactivity: self-efficacy and incentive value as regulators of cardiovascular adjustment.

The aim of this study was to verify the influence of self-efficacy and incentive value on cardiovascular reactivity. Ninety-six subjects were randomly assigned to four experimental groups in each of which the self-efficacy (high or low) and incentive value (high or low) were modified in relation to a mental arithmetic task. Subjects were led to believe that failure in this behaviour would result in the appearance of an aversive stimulus. Heart rate, systolic and diastolic blood pressure, pulse pressure and skin temperature were all recorded throughout task performance, and at two given moments prior to the task, in order to establish baseline values. Subjects with high self-efficacy experienced a smaller increase in heart rate and systolic pressure, a greater increase in diastolic pressure, greater reduction in skin temperature and a reduction in pulse pressure during task performance. The effects were moderated by the incentive value in such a way that the effects of self-efficacy on cardiovascular reactivity were stronger when the consequences of task failure were perceived as highly relevant (high incentive value).

Adolescent↗
PubMed2001

Flow-injection extraction-spectrophotometric method for the determination of ranitidine in pharmaceutical preparations.

The spectrophotometric determination of trace amounts of ranitidine was carried out by liquid-liquid extraction using bromothymol blue with a flow system. The determination of ranitidine in the range of 1 x 10(-5) - 1 x 10(-4) mol l(-1) was possible with a sampling frequency of 40 samples h(-1). The method was satisfactorily applied to the determination of ranitidine in pharmaceutical preparations and the recovery was quantitative and no interferences from excipients were observed.

Anti-Ulcer Agents↗
PubMed2001

Activation of defence-related genes during senescence: a correlation between gene expression and cellular damage.

The correlation between activation of defence-related gene expression and plant senescence was investigated by evaluating the presence of specific transcripts in various leaves of tobacco senescing plants. Expression of most genes examined was found to be induced shortly after flowering; however, each gene had its own characteristic timing of expression and level of RNA accumulation. Studies of the symptoms developed in senescing leaves responding to bacterial inoculation suggest that the accumulation of defence-related transcripts in these tissues might be related with the mechanism of senescence rather than with protection of the plant against pathogen infection. We observed that the high level of GUS expression directed by the beta-1,3-glucanase gn1 promoter, in senescing leaves of transgenic tobacco plants. decreased after bacterial inoculation, in correlation with the formation of symptoms. Reduction of gene expression was likely to be the reflection of the additional damage caused by the bacteria in the senescent tissues inoculated.

Gene Expression Regulation, Developmental↗
PubMed2001

Experimental study of bone response to a new surface treatment of endosseous titanium implants.

This study examines a new surface treatment that uses coarse calcium phosphate, which provides the benefits of surface roughening without introducing any foreign materials that may become imbedded in the implants. It is intended to enhance the use of implants in areas of inferior bone quality and quantity, such as the posterior areas of the maxilla and the mandible. Implants placed in the tibia of rabbits were removed after 16 weeks and examined microscopically. Pore sizes examined under the scanning electron microscope met the conditions described in the literature for successful integration. Optic microscopy revealed evidence of bone apposition over the roughened implant surface comparable to that seen in other surfaces. There was a definite absence of fibrous tissue, demonstrating good-to-excellent bone contact with the Restore Resorbable Blast Media implants (Lifecore Biomedical, Chaska, MN). In addition, it appears that the blasting of resorbable calcium phosphate on the machine titanium surface results in the resorbable blast media surface acting like an inert material. Further studies with a larger sample size are needed to confirm these initial findings.

Animals↗
PubMed2001

Abnormal EEG patterns in treatment-resistant schizophrenic patients.

This study was conducted in order to compare the EEG patterns of schizophrenics who do not respond to typical neuroleptics with those who do respond under typical neuroleptic medication and a group of controls. Absolute (AP) and relative power (RP), and inter- and intrahemispheric correlations were calculated. Nonresistant schizophrenics showed lower delta RP, higher alpha 1 AP and RP and higher correlation between prefrontal areas than the resistant ones and controls. Resistant schizophrenics showed lower alpha 2 RP, lower beta 1 and beta 2 in temporal but higher beta 2 AP and RP in occipital derivations, and higher intrahemispheric correlation between Fp2 and F4 and lower between F8 and T4 than the nonresistant and controls. The resistants also showed a higher antero-posterior beta 1 and beta 2 index than the controls. We concluded that the EEG pattern showed by the nonresistants may be associated with their good neuroleptic response that was not present in the resistant schizophrenics.

Adult↗
PubMed2000

Sensitive method for the determination of ambroxol in body fluids by capillary electrophoresis and fluorescence detection.

A sensitive and rapid capillary electrophoretic method combined with laser-induced fluorescence detection has been developed for the determination of ambroxol. Samples were derivatized with 5 x 10(-4) M fluorescein isothiocyanate. A linear relationship between concentration and peak area was obtained in the concentration range 0.008-42 microg ml(-1) with a correlation coefficient of 0.9999. The applicability of the method to serum and urine samples was demonstrated. The method is also useful for the determination of ambroxol in pharmaceutical preparations.

Ambroxol↗
PubMed2000

Protein nutrition in fish: protein/energy ratio and alternative protein sources to fish meal.

Those interested in the design and manufacture of feeds for intensive fish farming face the basic concern of formulating mixtures for the best yield at the lowest costs. Of the macronutrients in the feed, protein has and continues to receive special consideration because fish present high and specific needs for this constituent. Traditionally, protein has been supplied primarily by fish meals. This paper presents a synthesis of the efforts made and the lines explored to achieve an effective reduction of the amount of fish meal in the feeds for fish, following two strategies: reduction of the protein in the feeds and the use of new raw materials to replace fish meal.

Animal Feed↗
PubMed2000

Inhibition of prostaglandin E2 and leukotriene C4 in mouse peritoneal macrophages and thromboxane B2 production in human platelets by flavonoids from Stachys chrysantha and Stachys candida.

Seven flavonoids of Stachys chrysantha and Stachys candida have been isolated. The structures of the compounds were elucidated by spectroscopic methods, particularly highfield NMR spectroscopy. The effects of the methanol extracts of these two endemic Greek Stachys sp. and their main flavonoids were examined on arachidonic acid (AA) metabolism in the cellular system (mouse peritoneal macrophages and human platelets). Their cytotoxicity on cells was also investigated. Most samples assayed did not exhibit any significant effect on prostaglandin E2 (PGE2)-release from calcium ionophore-stimulated mouse peritoneal macrophages. Only chrysoeriol-7-O-beta-(3''-E-p-coumaroyl)-glucopyranoside, at the highest non-cytotoxic dose (50 microM), inhibited the release of PGE2, but this effect is not statistically significant. The release of leukotriene C4 (LTC4) by mouse peritoneal macrophages stimulated with calcium ionophore was inhibited by a crude extract of S. chrysantha, with an IC50 value of 34.3 microg/ml. Xanthomicrol (IC50 = 29.2 microM) and chrysoeriol-7-O-beta-D-(3''-E-p-coumaroyl)-glucopyranoside (IC50 = 11.1 microM) also inhibited the release of LTC4, although it showed less potency than the reference compound nordihydroguaiaretic acid (NDGA) (IC50 = 2 microM). However, most samples assayed showed a significant effect on thromboxane B2 (TXB2)-release from calcium ionophore-stimulated human platelets, with inhibition percentages slightly lower than the reference drug ibuprofen (IC50 = 7 microM). The IC50 values are: crude extract of S. candida 23.3 microg/ml; crude extract of S. chrysantha 23.1 microg/ml; xanthomicrol 28.8 microM; calcycopterin 2.66 microM and chrysoeriol-7-O-beta-D-(3''-E-p-coumaroyl)-glucopyranoside 8.8 microM. Our results indicate that the selective inhibition of TX-synthase enzyme may be the primary target of action of most of these samples, and one of the mechanisms through which thus exert their antiinflammatory effects.

Animals↗
PubMed2000

Preweaning growth curves in Brown Swiss and Pirenaica calves with emphasis on individual variability.

A quadratic polynomial model with random regression coefficients was used to describe preweaning growth curves of two beef cattle breeds widely used in the Spanish Pyrenees, according to genotype and season of birth effects. In addition, parameters of individual variability that can be used in a stochastic model were obtained. Data recorded indoors from birth to weaning of 217 Brown Swiss calves (3,509 observations) born either in spring or autumn (BS-S, BS-A) and 101 spring-born Pirenaica calves (PI-S, 967 observations) were analyzed. A quadratic model accurately fitted the preweaning weights (R2 = .99). Use of random regression coefficients improved the weaning weight adjustment; the residual variance of the model with intercept and linear random coefficients (9.61 kg2) was smaller than that of the model without them (130.03 kg2). Brown Swiss-S and PI-S calves had similar birth weight (40.9 +/- .96 vs 39.4 +/- .73 kg), but BS-S calves achieved significantly higher weaning weights at 150 d of age (175.2 +/- 2.45 vs 158.4 +/- 3.17 kg). Preweaning growth patterns were different for each season of birth, but there were no differences in weaning weight at 150 d of age (172.9 +/- 2.01 BS-A vs 175.2 +/- 2.45 BS-S). Standardization of weaning weights using a linear approximation could lead to biases, especially when comparing animals from the two calving seasons. The estimate of variances of random parameters should be done within breed and season of birth in order to take into account heteroscedasticity. The variances for BS-A, BS-S, and PI-S were 39.9, 57.6, and 32.2 kg2 for the intercept, respectively, and .0159, .0141, and .0205 kg2 for the linear coefficient. Covariance between the intercept and the linear coefficient (.34 kg2) was only statistically significant in the case of BS-S. The individual variance of weight at 150 d was 424.7 kg2 and 526.7 kg2 for BS-S and PI-S, respectively, almost 65% of the observed variance of weaning weight.

Animals↗
PubMed2000

[Reduction of anxiety in the anteroom of the operating theater in pediatric patients].

Research indicates that anxiety before surgical intervention in paediatric patients negatively affects on post hospital recovery. Numerous investigations are, therefore, conducted to alleviate anxiety through different psychological techniques at this critical moment that the child is undergoing in surgery. In our case, we have considered one of the resources of the Sant Joan de Déu Hospital: a voluntary team that works in the anteroom of the operating theatre to keep the children company. The aim of our research has been to train these volunteers (who previously did not have any specific training for their task) and to observe the effect on the children's anxiety. The subjects of our study were 140 boys and girls between the ages of 0 and 18 years old. Results indicate that training not only produces significative changes on volunteers' behaviour, but also has resulted in the children's presurgical anxiety behaviour. In this way, we recommend that all children be accompanied by a trained volunteer.

Adolescent↗
PubMed1999

alpha-oxidation of fatty acids in higher plants. Identification of a pathogen-inducible oxygenase (piox) as an alpha-dioxygenase and biosynthesis of 2-hydroperoxylinolenic acid.

A pathogen-inducible oxygenase in tobacco leaves and a homologous enzyme from Arabidopsis were recently characterized (Sanz, A., Moreno, J. I., and Castresana, C. (1998) Plant Cell 10, 1523-1537). Linolenic acid incubated at 23 degrees C with preparations containing the recombinant enzymes underwent alpha-oxidation with the formation of a chain-shortened aldehyde, i.e., 8(Z),11(Z), 14(Z)-heptadecatrienal (83%), an alpha-hydroxy acid, 2(R)-hydroxy-9(Z),12(Z),15(Z)-octadecatrienoic acid (15%), and a chain-shortened fatty acid, 8(Z),11(Z),14(Z)-heptadecatrienoic acid (2%). When incubations were performed at 0 degrees C, 2(R)-hydroperoxy-9(Z),12(Z),15(Z)-octadecatrienoic acid was obtained as the main product. An intermediary role of 2(R)-hydroperoxy-9(Z), 12(Z),15(Z)-octadecatrienoic acid in alpha-oxidation was demonstrated by re-incubation experiments, in which the hydroperoxide was converted into the same alpha-oxidation products as those formed from linolenic acid. 2(R)-Hydroperoxy-9(Z),12(Z), 15(Z)-octadecatrienoic acid was chemically unstable and had a half-life time in buffer of about 30 min at 23 degrees C. Extracts of cells expressing the recombinant oxygenases accelerated breakdown of the hydroperoxide (half-life time, about 3 min at 23 degrees C), however, this was not attributable to the recombinant enzymes since the same rate of hydroperoxide degradation was observed in the presence of control cells not expressing the enzymes. No significant discrimination between enantiomers was observed in the degradation of 2(R,S)-hydroperoxy-9(Z)-octadecenoic acid in the presence of recombinant oxygenases. A previously studied system for alpha-oxidation in cucumber was re-examined using the newly developed techniques and was found to catalyze the same conversions as those observed with the recombinant enzymes, i.e. enzymatic alpha-dioxygenation of fatty acids into 2(R)-hydroperoxides and a first order, non-stereoselective degradation of hydroperoxides into alpha-oxidation products. It was concluded that the recombinant enzymes from tobacco and Arabidopsis were both alpha-dioxygenases, and that members of this new class of enzymes catalyze the first step of alpha-oxidation in plant tissue.

Aldehydes↗
PubMed1999

Antigenic profile of African horse sickness virus serotype 4 VP5 and identification of a neutralizing epitope shared with bluetongue virus and epizootic hemorrhagic disease virus.

African horse sickness virus (AHSV) causes a fatal disease in horses. The virus capsid is composed of a double protein layer, the outermost of which is formed by two proteins: VP2 and VP5. VP2 is known to determine the serotype of the virus and to contain the neutralizing epitopes. The biological function of VP5, the other component of the capsid, is unknown. In this report, AHSV VP5, expressed in insect cells alone or together with VP2, was able to induce AHSV-specific neutralizing antibodies. Moreover, two VP5-specific monoclonal antibodies (MAbs) that were able to neutralize the virus in a plaque reduction assay were generated. To dissect the antigenic structure of AHSV VP5, the protein was cloned in Escherichia coli using the pET3 system. The immunoreactivity of both MAbs, and horse and rabbit polyclonal antisera, with 17 overlapping fragments from VP5 was analyzed. The most immunodominant region was found in the N-terminal 330 residues of VP5, defining two antigenic regions, I (residues 151-200) and II (residues 83-120). The epitopes were further defined by PEPSCAN analysis with 12mer peptides, which determined eight antigenic sites in the N-terminal half of the molecule. Neutralizing epitopes were defined at positions 85-92 (PDPLSPGE) for MAb 10AE12 and at 179-185 (EEDLRTR) for MAb 10AC6. Epitope 10AE12 is highly conserved between the different orbiviruses. MAb 10AE12 was able to recognize bluetongue virus VP5 and epizootic hemorrhagic disease virus VP5 by several techniques. These data will be especially useful for vaccine development and diagnostic purposes.

African Horse Sickness Virus↗