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Biomedical subjects

C Izquierdo

Publications and source records attributed to C Izquierdo.

At least 19 recordsLinked to original sources
PubMed2001

Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain.

The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: < or = 5, 6-7 and 13-14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 degrees C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5.34%) meningococcal carriers were detected: 63 B (4.5%), 9 non groupable (0.7%), 2 29E (0.1%) and 1X (0.07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68.9% in children 6-7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, recent upper respiratory tract infection, previous antibiotic treatment, number of students in the class, size of the classroom and social class. Multivariate analysis found that only age and previous antibiotic treatment remained statistically significant when the other factors were controlled.

Adolescent↗
PubMed1997

[Traumatic asphyxia and continuous venovenous hemofiltration. Report of a case].

A 32-year-old man was admitted with traumatic asphyxia, with aspiration to the bronchi after being buried under sand. The condition progressed to respiratory distress syndrome and systemic inflammatory response. Because ventilatory and hemodynamic deterioration was rapid and severe, in spite of mechanical ventilation and vasoactive drugs, we instated early continuous arteriovenous hemofiltration, which also allowed us to meet the patient's full nutritional needs. We believe that the patient's very satisfactory progress can be attributed to the early use of this procedure, along with appropriate specific treatment.

Accidents, Occupational↗
PubMed1996

Effect of kappa-casein split peptides on platelet aggregation and on thrombus formation in the guinea-pig.

An undecapeptide (residues 106-116 of cow kappa-casein) is known to inhibit human platelet aggregation and fibrinogen binding through inhibition of the interaction between the fibrinogen gamma-chain C-terminus and alphaIIbbeta3. This was due to structural homologies with the fibrinogen gamma-chain C-terminal dodecapeptide. We have therefore compared in this work the in vitro anti-aggregating activity of kappa-casein split peptides and their in vivo potential antithrombotic activity in a model of arterial thrombosis triggered by laser-induced intimal injury in the guinea-pig. Caseinoglycopeptide (residues 106-169), the undecapeptide (residues 106-116) and the pentapeptide KNQDK (residues 112-116) from cow kappa-casein, were anti-aggregating peptides and exerted a significant antithrombotic activity in the guinea-pig. Caseinoglycopeptides from three species (cow, ewe and human) were also antithrombotic and the most potent being the human one. The antithrombotic activity was achieved in vivo for doses less than the one suspected from in vitro data and for which, ex vivo platelet aggregation was not decreased. In conclusion, the relative involvement of the fibrinogen gamma-chain C-terminal dodecapeptide could be much more important in in vivo thrombosis process than in in vitro platelet aggregation. Its specificity and activity in vivo unveiled an interesting potential way for inhibition of arterial thrombosis if alternative molecular presentation (i.e. peptidomimetics) and alternative route (i.e. per os) can be developed.

Amino Acid Sequence↗
PubMed1996

US and color Doppler imaging of ocular and orbital disease in the pediatric age group.

Ultrasonography (US) is a rapid, accurate, noninvasive method of evaluating ocular and orbital disease. A wide spectrum of pediatric ocular and orbital disorders can be demonstrated with US: ocular congenital malformations, vitreoretinal disorders, primary and metastatic ocular and orbital neoplasms, inflammatory and congestive disease (focal or systemic), cystic disease, trauma, and foreign bodies. US may be the method of choice for studying ocular congenital anomalies and vitreoretinal disorders owing to its high definition and noninvasiveness. In ocular neoplasms, US demonstrates the morphology of the lesion, its solid or liquid nature, and the presence of calcifications. Its use is limited when the tumor extends outside the globe; computed tomography (CT) or magnetic resonance (MR) imaging must then be performed. In ocular trauma, US precisely demonstrates the presence of hemorrhage, retinal and choroidal detachment, and foreign bodies. CT and MR imaging are superior in evaluation of orbital disease. Color Doppler US often allows differential diagnosis of vascular, inflammatory, and neoplastic disease.

Child↗
PubMed1996

[Evaluation of chromogenic medium CPS ID2 (bioMérieux) in urine cultures].

BACKGROUND: The aim of the study was to evaluate the chromogenic agar plate CPS ID2 (bioMérieux) and determine its cost-benefit ratio. METHODS: A total of 2,193 urinary sediments were processed. The urine culture was carried out in CPS ID2 agar and in cystine-lactose electrolyte deficient (CLED) agar, when needed. Identification of the microorganisms was performed following standard microbiologic procedures through biochemical tests prepared in our laboratory. The identification, from CPS ID2 agar, by direct detection in medium of four metabolic activities: beta-glucuronidase, beta-glucosidase, deaminase, and indol production, was performed following to manufacturer's instructions. RESULTS: A total of 289 urine cultures were positive, 18 were negative and 34 were contaminated samples. The identification, directly performed from the colonies detected in CPS ID2 agar, was correct in 96% of 166 Escherichia coli, in 92% of 24 Proteus mirabilis and in 97% of 38 enterococci. CPS ID2 agar exhibited 94% and 100% sensitivity and specificity, respectively in E. coli identification, 92% and 100% in P. mirabilis and 97% and 99% in Enterococcus. The use of this new media, CPS ID2, in our laboratory, implies a budgetary increment. However, if commercial galleries are used for routine identification, the cost will be reduced using this new media. CONCLUSIONS: The CPS ID2 agar allows the isolation and direct identification of the most frequent urinary tract pathogens: E. coli, P. mirabilis and Enterococcus in primary isolation medium. Using this medium, bacteriologists will be able to save time and reagents when identifying the most common uropathogens. Furthermore, the use of this medium would reduce costs in some laboratories.

Agar↗
PubMed1995

Characterization of an antithrombotic peptide from kappa-casein in newborn plasma after milk ingestion.

Bovine and human kappa-caseinoglycopeptides, two antithrombotic peptides derived from the corresponding kappa-caseins, were detected in physiologically active concentrations in the plasma of 5-d-old newborn infants after ingestion of cow's-milk-based formula or human milk respectively. It is suggested that these two bioactive peptides are released from milk proteins during digestion.

Amino Acid Sequence↗
PubMed1992

In search of a correlation between the electron affinity and the radiosensitizing activity of some glyoxylic compounds.

The electron affinity of some glyoxylic compounds with radiosensitizing properties was evaluated using different approaches. The half-wave reduction potentials were measured by polarography, and the molecular structures in solution were determined by NMR spectroscopy. The electron affinity of the unhydrated and hydrated molecules was theoretically evaluated by means of a semi-empirical quantum mechanical procedure, the MNDO. The possible correlations between these values and the radiosensitizing efficiency of these glyoxylic compounds is discussed.

Electrochemistry↗
PubMed1988

Kinetic study of the enzyme NADPH cytochrome-C (P-450) reductase: non-Michaelian behaviour.

1. Contrary to what has been accepted until now, the enzyme exhibits non-Michaelian kinetics both against NADPH and against cytochrome-c as substrates; deviations were detected that have led to the proposition of a rate equation of minimum degree 2:2. 2. A general mechanism is proposed that includes, apart from the binding of the enzyme to NADPH, the formation of an enzyme-cytochrome-c complex, both routes leading to the formation of a ternary-complex NADPH-enzyme-acceptor. 3. From the latter, a series of intermediate steps finally leads to the release of the enzyme in conditions to start a new catalytic cycle. 4. Application of the King-Altman method to this mechanism yields a kinetic equation of degree 2:2 with respect to the cytochrome-c and NADPH, in accordance with our experimental results.

Animals↗
PubMed1987

The non-Michaelian action of thrombin on peptide p-nitroanilide substrates.

1. v([S]) kinetic data were obtained for the hydrolysis of the chromogenic substrates H-D-Phe-L-Pip-L-Arg-pNA (S-2238), H-D-Ile-L-Pro-L-Arg-pNA (S-2288), Tos-Gly-L-Pro-L-Arg-pNA (Tos-Ch-TH) and Cbz-Gly-L-Pro-L-Arg-pNA (Cbz-Ch-TH) by native human thrombin under different experimental conditions (Pip is pipecolyl, pNA is p-nitroanilide, Tos is tosyl and Cbz is benzyloxycarbonyl). 2. The data were fitted to rational functions of order 1:1, 2:2 and 3:3 by using non-linear regression. Discrimination between equations of different degree was made using the F-test. 3. In all, 24 curves were fitted. In 17 cases degree 2:2 was significantly better than degree 1:1 at a confidence level of 95%. In no case was any further significant improvement found with functions of degree 3:3. 3. Our results allow us to assert that native human thrombin is an enzyme that does not allow Michaelian kinetic behaviour when acting on chromogenic substrates. Instead, the empirically obtained steady-state data require mechanisms whose rate equation is at least of degree 2:2.

Anilides↗
PubMed1987

Kinetic study of the inhibition of the amidolytic activity of thrombin by benzamidine and N-dansyl-(p-guanidino)-phenylalanine-piperidide (I-2581).

1. v([I]) data were obtained for the hydrolysis of the chromogenic substrate H-D-Phe-L-Pip-L-Arg-pNA (S-2238) by native human thrombin in the presence of the synthetic inhibitors Benzamidine and N-dansyl-(p-guanidino)-phenylalanine-piperidide (I-2581). v([S]) data were also obtained in the absence and presence of fixed concentrations of each of the inhibitors. 2. Analysis of the kinetic data was based on the numerical fitting to rate equations of the polynomial quotient type of degree n:m using nonlinear regression methods. The discrimination between rate equations with different degrees was performed by application of the statistical F test. 3. Of eight v([I]) curves fitted, in six cases it was found that degree 1:2 was significantly better than degree 1:1 at a confidence level of 95% or higher; in no case was a significant improvement found with rate equations with a higher number of parameters. For the v([S]) data, of eleven curves fitted it was found that in nine cases degree 2:2 significantly improved degree 1:1 at confidence levels 99% and in one case at a level of 95%; no significant improvement was found with rate equations of higher degree for these data either. 4. Our findings allow us to propose that inhibition of the amidolytic activity of native human thrombin by benzamidine and I-2581 may be accounted for by mechanisms whose v([I]) rate equation will be a minimum of degree 1:2, thus implying a pure inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Amides↗