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Biomedical subjects

R Aguilera

Publications and source records attributed to R Aguilera.

17 recordsLinked to original sources
PubMed2006

Enhancement of enrofloxacin serum antibacterial activity by calcium primed broilers.

The aim of this trial was to assess the effect that calcium gluconate priming of 468 broilers has on the antibacterial activity of a standard dose of enrofloxacin. Hence, a series of oral pharmacokinetic studies were carried out in four groups of broilers medicated individually through an oral cannula as follows: group A, medicated only with enrofloxacin 10mg/kg; group B, receiving immediately one after the other, calcium gluconate (200mg/kg) and enrofloxacin 10mg/kg; group C, dosed first with calcium gluconate (200mg/kg) and 1h later enrofloxacin (10mg/kg); and group D, dosed first with calcium gluconate (200mg/kg) and 2h later enrofloxacin (10mg/kg). Broilers were bled at different times after the dose of enrofloxacin and antibacterial activity, measured as concentration of enrofloxacin, was measured by an agar diffusion assay. Results revealed that group D the greatest values of maximum serum concentration (Cs(max)), area under the concentration vs. time curve (AUC) and area under the moment curve (AUMC). These values were statistically higher than the corresponding ones derived from groups A, B and C (P<0.05). Taking Cs(max) and AUC values of group A as reference baseline, an increase of 24% and 50%, respectively, was obtained in group D. Group B had the lowest Cs(max), AUC, AUMC and elimination half life (T(1/2)beta) and these values were statistically different from groups A, C and D (P<0.05). The T(1/2)beta was statistically longer in groups C and D as compared with A and B, and the former groups were also different between each other (P<0.05). These results show that if calcium gluconate is first dosed to broilers and 2h later enrofloxacin is administered (as in group D), a more pronounced antibacterial activity of enrofloxacin can be obtained. A challenge of this sequential dosing scheme in a field trial may reveal its clinical value.

Animals↗
PubMed2004

Influence of hard water on the bioavailability of enrofloxacin in broilers.

To define the impact that use of different levels of hard water has on the bioavailability of the antibacterial, enrofloxacin, in poultry, an oral bioavailability-pharmacokinetic study of the drug was carried out. Two hundred fifty clinically healthy broilers, divided into 5 groups, were individually dosed orally with 10 mg/kg of enrofloxacin diluted to 0.1%. The enrofloxacin was diluted with water of increasing hardness in accordance with an international grading system. After dosing, blood samples were obtained at predetermined times. Serum was recovered and quantified for enrofloxacin by means of an agar diffusion bacteriological method. The composite serum concentrations of enrofloxacin and metabolites vs. time relationships were analyzed using software for compartmental pharmacokinetics. Results show that there were statistically significant differences in the following pharmacokinetic variables: maximal serum concentrations (Csmax), area under the time vs. concentration curves, and half-lives of the elimination phases. The means of these values showed a linear decay of Csmax from one group to the next as water hardness increased. Chemical analysis of water calcium and magnesium ions revealed the formation of coordination groups. Lack of interference with the microbiological activity in vitro of enrofloxacin diluted in hard water indicated that diminished absorption may be partly responsible for reduction in bioavailability. These results stress the need for proper water supply when enrofloxacin is used and point out a factor that must be taken into account when clinical outcomes do not comply with expectations.

Animals↗
PubMed2003

CodY is a nutritional repressor of flagellar gene expression in Bacillus subtilis.

Expression of the sigma(D)-dependent flagellin gene, hag, is repressed by the CodY protein in nutrient-rich environments. Analysis of a codY mutant bearing a hag-lacZ reporter suggests that the availability of amino acids in the environment is the specific signal that triggers this repression. Further, hag-lacZ expression appears to be sensitive to intracellular GTP levels, as demonstrated by increased expression upon addition of decoyinine. This result is consistent with the postulate that the availability of amino acids in the environment effects intracellular GTP levels through the stringent response. However, the levels of hag-lacZ measured upon the addition of subsets of amino acids suggest an additional mechanism(s). CodY is a DNA binding protein that could repress flagellin expression directly by binding to the hag promoter region, or indirectly by binding to the fla/che promoter region that governs expression of the sigma(D) transcriptional activator required for hag gene expression. Using an electrophoretic mobility shift assay, we have demonstrated that purified CodY protein binds specifically to both the hag and fla/che promoter fragments. Additionally, CodY acts as a nutritional repressor of transcription from the fla/che promoter region that contains two functional promoters. CodY binds to both the sigma(D)- and sigma(A)-dependent promoters in this region, as demonstrated by DNase I footprint analyses. Footprint analyses of the hag gene demonstrated that CodY binds downstream of its sigma(D)-dependent promoter. Taken together, these results identify new members of the CodY regulon that encode motility functions in Bacillus subtilis and are controlled by the sigma(D) alternate sigma factor.

Amino Acids, Branched-Chain↗
PubMed2001

Performance characteristics of a carbon isotope ratio method for detecting doping with testosterone based on urine diols: controls and athletes with elevated testosterone/epitestosterone ratios.

BACKGROUND: Carbon isotope ratio methods are used in doping control to determine whether urinary steroids are endogenous or pharmaceutical. METHODS: Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was used to determine the delta(13)C values for 5 beta-androstane-3 alpha,17 beta-diyl diacetate (5 beta A), 5 alpha-androstane-3 alpha,17 beta-diyl diacetate (5 alpha A), and 5 beta-pregnane-3 alpha,20 alpha-diyl diacetate (5 beta P) in a control group of 73 healthy males and 6 athletes with testosterone/epitestosterone ratios (T/E) >6. RESULTS: The within-assay precision SDs for 5 beta A, 5 alpha A, and 5 beta P were +/- 0.27 per thousand, +/- 0.38 per thousand, and +/- 0.28 per thousand, respectively. The between-assay precision SDs ranged from +/- 0.40 per thousand to +/- 0.52 per thousand. The system suitability and batch acceptance scheme is based on SDs. For the control group, the mean delta(13)C (SD) values were -25.69 per thousand (+/- 0.92 per thousand), -26.35 per thousand (+/- 0.68 per thousand), and -24.26 per thousand (+/- 0.70 per thousand), for 5 beta A, 5 alpha A, and 5 beta P, respectively. 5 beta P was greater than 5 beta A and 5 alpha A (P <0.01), and 5 beta A was greater than 5 alpha A (P <0.01). The means - 3 SD were -28.46 per thousand, -28.39 per thousand, and -26.37 per thousand for 5 beta A, 5 alpha A, and 5 beta P, respectively. The maximum difference between 5 beta P and 5 beta A was 3.2 per thousand, and the maximum 5 beta A/5 beta P was 1.13. Three athletes with chronically elevated T/Es had delta(13)C values consistent with testosterone administration and three did not. CONCLUSIONS: This GC-C-IRMS assay of urine diols has low within- and between-assay SDs; therefore, analysis of one urine sample suffices for doping control. The means, SDs, +/-3 SDs, and ranges of delta(13)C values in a control group are established. In comparison, testosterone users have low 5 beta A and 5 alpha A, large differences between 5 beta A or 5 alpha A and 5 beta P, and high 5 beta A/5 beta P and 5 alpha A/5 beta P ratios.

Androstane-3,17-diol↗
PubMed2000

A rapid screening assay for measuring urinary androsterone and etiocholanolone delta(13)C ( per thousand) values by gas chromatography/combustion/isotope ratio mass spectrometry.

A gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) method is described and validated for measurement of delta(13)C values of the acetate derivatives of urinary etiocholanolone and androsterone. The analysis was performed with only 2 mL of urine. The sample preparation consisted of deconjugation with beta-glucuronidase, solid phase extraction, and derivatization with acetic anhydride and pyridine. The within-assay precision of two quality control (QC) urine samples ranged from 0.5 to 2.1 CV%. The between-assay precision in the same QC urines ranged from 1.7 to 3.4 CV%. Administration of testosterone enanthate to a subject resulted in a 6 per thousand decrease in delta(13)C values from -25 per thousand (baseline) to -31 per thousand. Two weeks after testosterone administration was discontinued, the delta(13)C values remained abnormally low while the urine testosterone/epitestosterone (T/E) ratio returned to less than 6. This relatively simple method is useful for rapidly screening a large number of urine samples, including those with T/E <6.

Adult↗
PubMed2000

[Triple therapy of short-term with azithromycin, amoxycillin and omeprazole for the eradication of Helicobacter pylori].

BACKGROUND: The high cost and complexity of therapeutic schemes for the eradication of Helicobacter pylori has stimulated the search of simpler and cheaper treatment options. AIM: To evaluate the efficacy of 3 days of azithromycin 500 mg od, 7 days of amoxycillin 750 mg tid and omeprazole, 20 (Group A) or 40 mg (Group B) on randomization, as a treatment for Helicobacter pylori infection in patients with endoscopically diagnosed peptic ulcer. METHODS: H. pylori status of peptic ulcer patients was pathologically confirmed by the examination of five gastric biopsies using the Giemsa stain and by rapid urease testing in two gastric biopsies. H. pylori status was reassessed not less than 28 days after completing treatment. Adverse events and compliance were evaluated. RESULTS: Fifty four patients (29 men, 25 women, mean age 48 years) were enrolled, 28 in Group A and 27 in Group B. Per protocol the infection was cured in 58.8% of patients (30/51; 95% CI: 45-73%). On an intention to treat basis, H pylori infection was cured in 55%. Minor side effects including diarrhea and nausea were reported by 32% of patients. Ninety-five per cent of patients consumed more than 95% of prescribed medications. H. pylori was successfully eradicated in 61% of group A and 57% of group B patients (p = NS). CONCLUSION: Short term therapy with azithromycin was poorly effective in curing H. pylori infection. The compliance was excellent. Increasing Omeprazole from 20 to 40 mg/day did not improve treatment effectiveness.

Amoxicillin↗
PubMed1999

Screening urine for exogenous testosterone by isotope ratio mass spectrometric analysis of one pregnanediol and two androstanediols.

We propose a new screening method for testosterone (T) doping in sport. The current method for detecting T administration is based on finding a T to epitestosterone ratio (T/E) in urine that exceeds six. The difficulties with T/E are that T administration does not always result in a T/E>6 and that a rare individual will have T/E>6 in the absence of T administration. Our previous studies reveal that carbon isotope ratio helps to determine the origin of the urinary T because the values for T and its metabolites decrease after the administration of exogenous T. In this study, we present a rapid and efficient screening sample preparation method based on three successive liquid-solid extractions, deconjugation with E. coli beta-glucuronidase after the first extraction, acetylation after the second extraction, and a final extraction of the acetates. The 13C/12C of two T metabolites (5beta-androstane-3alpha,17beta-diol and 5alpha-androstane-3alpha,17beta-diol) and one pregnanediol as endogenous reference (5beta-pregnane-3alpha,20alpha-diol) was measured by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) on 10 ml of urine collected from 10 healthy men before and after T administration. Following T administration, the 13 C/12C of 5beta-androstane-3alpha,17beta-diol diacetate and 5alpha-androstane-3alpha,17beta-diol diacetate declined significantly from -26.2 per thousand to -30.8 per thousand and from -25.2 per thousand to -29.9 per thousand, respectively and the 13C/12C of 5beta-pregnane-3alpha,20alpha-diol diacetate was unchanged. In addition, the ratio of androstanediols to pregnanediol increased in the post-T urines.

Adult↗
PubMed1997

Detection of exogenous hydrocortisone in horse urine by gas chromatography-combustion-carbon isotope ratio mass spectrometry.

A gas chromatography-combustion-isotope ratio mass spectrometry method for confirmation of hydrocortisone abuse in horseracing and equine sports is proposed. Urinary hydrocortisone was converted to a bismethylenedioxy derivative which presents good gas chromatographic properties and brings an extra carbon contribution of only two carbon atoms. Synthetic hydrocortisone has a different 13C abundance from that of natural urinary horse hydrocortisone and the difference is significant, therefore exogenous and endogenous hydrocortisone can be distinguished.

Animals↗
PubMed1996

Detection of testosterone misuse: comparison of two chromatographic sample preparation methods for gas chromatographic-combustion/isotope ratio mass spectrometric analysis.

Two chromatographic methods, reversed-phase liquid chromatography (LC) and immunoaffinity chromatography (IAC), were compared in the preparation of purified testosterone extracts suitable for gas chromatography-combustion/isotope ratio mass spectrometry (GC-C-IRMS) analysis. We have shown previously that GC-C-IRMS is a promising means of detection of testosterone misuse in sport. The two clean-up procedures afford sufficient recovery and adequate purity of testosterone. LC presents several advantages over IAC: access to other urinary steroids, longer column life, no need for special equipment and no antibody preparation. For IAC, the antibodies to testosterone must be selected with care for high affinity and low cross-reactivity. Nevertheless, IAC is of some interest in our experiments, the recovery is slightly better for low concentrations of urinary testosterone and IAC does not induce isotopic discrimination even in overloading experiments. This is the first report on sample preparation by IAC prior to GC-C-IRMS and carbon isotope ratio values for urinary epitestosterone. The carbon isotope ratio test can identify users' urines missed by the testosterone to epitestosterone ratio (T/E > 6) test.

Antibodies↗
PubMed1996

Improved method of detection of testosterone abuse by gas chromatography/combustion/isotope ratio mass spectrometry analysis of urinary steroids.

The current approach to detection of doping with testosterone is based on measuring the testosterone to epitestosterone ratio (T/E) in urine by gas chromatography/mass spectrometry. The median T/E for healthy males who have not used T is about 1.0. In a single urine, a T/E lower than six leads to a negative report even though it does not exclude T administration. A value greater than six indicates possible T administration or a naturally elevated ratio. It has been shown previously that the carbon isotope ratio of urinary T changes after T administration. In this study a potential confirmation method for T abuse was optimized. Gas chromatography/combustion/carbon isotope ratio mass spectrometry (GC/C/IRMS) was used to analyze two T precursors (cholesterol and 5-androsten-3 beta, 17 beta-diol) and two T metabolites (5 alpha- and 5 beta-androstane-3 alpha, 17 beta-diol) in addition to T itself in each of 25 blind urines collected from eight healthy men before, during or after T administration. The carbon isotope ratios of T and the metabolites were lower after T administration. The relationships among the variables were studied using multivariate analysis and beginning with principal components analysis; cluster analysis revealed that the data are composed of two clusters, and classified the samples obtained after T administration in one cluster and the remainder in the other; discriminant analysis correctly identified T users. The measurement of carbon isotope ratios of urinary androgens is comparable to the T/E > 6 test and continues to show promise for resolving cases where doping with T is suspected.

Adult↗
PubMed1996

[Evaluation of an informative leaflet on AIDS/HIV infection aimed at primary health care professionals in Catalonia].

OBJECTIVE: To assess primary care professionals' understanding and acceptance of a periodic information leaflet on HIV/AIDS. DESIGN: Crossover. SETTING: Primary care teams from the Institut Català de la Salut. PARTICIPANTS: A random sample of 300 doctors, qualified nurses and social workers. INTERVENTION: A self-administered, anonymous questionnaire returned by normal post. MEASUREMENTS AND MAIN RESULTS: Questions covered the following thematic areas: clinical care of people infected by HIV/AIDS and requests for diagnostic tests for infection, perception of skills in the promotion of changes in patients' sexual behaviour and drug use, providing psychological support and guidelines for integrating HIV+ children in schools and information on social resources. 60% knew the publication. Thematic areas which aroused most interest were: psychological support for people affected, prevention of HIV infection in the health environment, clinical advice and diagnosis. 77% had received requests for diagnostic tests and 88% had attended infected people. CONCLUSIONS: In spite of the low reply rate (50%) and relative variability among the professionals and the health regions they came from, this first assessment enabled us to identify specific educational needs in the care and prevention of HIV/AIDS infection in the primary care framework and also to improve the distribution methods we used.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Gas chromatography/combustion/isotope-ratio mass spectrometry analysis of urinary steroids to detect misuse of testosterone in sport.

We propose a new confirmatory method for testosterone doping in sport. The present method in use, based on measuring the testosterone/epitestosterone (T/E) ratio in urine, may miss suspicious cases, or lead to reporting cases in which the high ratio is natural. Synthetic testosterone has a 13C abundance different from that of endogenous human testosterone. The connection of a gas chromatograph to an isotope-ratio mass spectrometer via a combustion interface allows the measurement of the corresponding characteristic value (delta /1000) for testosterone, its precursors, and its metabolites. To detect exogenous administration of testosterone, 30-40 mL of urine is sufficient.

Acetylation↗
PubMed1990

[Serum level determination of local anesthetics using high pressure liquid chromatography].

We report a high resolution liquid chromatography method for simultaneous determination of lidocaine, mepivacaine and bupivacaine in serum using cyclicine as a standard. Drugs are extracted from serum using dichloromethane in an alkaline medium type columns in a mobile phase with 0.1 M phosphate buffer at pH 7.5, methanol and acetonitrile (33:17:50) were used for separation. Spectrophotometric measurement was performed at 207 nm. In a concentration ranging from 0.5 to 8 micrograms/ml, r values of 0.997, 0.989 and 0.998 were obtained for lidocaine, mepivacaine and bupivacaine, respectively. The coefficient of variation estimated at 2 micrograms/ml was 2, 19, 2.76 and 2.48%, respectively. A maximal error of 4.5%, 3.6% and 2.9% found for "inter day" repeated measurement at the above concentration for each drug. Thus, high sensitivity, reproducibility and relative simpleness of the method are demonstrated for its clinical use in determination of serum levels of local anesthetics.

Anesthetics, Local↗
PubMed1990

Recruitment methods and differences in early, late and non-respondents in the first MONICA-Catalonia population survey.

The early response rate in the first MONICA-Catalonia population survey was 52.7% and the final response rate was 73.8%. The intensity of recruitment effort in this survey led to a considerable increase in response rate (20%), with the extra cost per late respondent being relatively low ($13.9). Added recruitment effort was most effective in the youngest age group, 25-34 years. It was also more effective among women living in urban areas than among those from rural areas. In men, early respondents had a higher proportion of smokers than late respondents, and in women, early respondents had higher systolic and diastolic blood pressure levels and were more aware of their history of high blood pressure than late respondents. Non-respondents were less educated than respondents in both sexes, and this was more marked in women. No differences were found in the proportion of smokers between respondents and non-respondents. Respondents were more aware of their high blood pressure history than non-respondents. The recruitment costs and distribution of non-response components are given.

Adult↗
PubMedDate not supplied

[Cerebral ischemia: a complication in heart catheterization. An assessment in 2178 catheterizations].

Cardiac catheterization is highly recognized as the more definitive test in several cardiac diseases. However it has a small but definite risk. Cerebral ischemia is an unusual complication of this procedure; the main recognized physiopathological mechanism is thromboembolism. We present the analysis of 7 cases observed in 2178 consecutive cardiac catheterizations. In all cases the neurological dysfunction developed during the procedure or in the few minutes after it. One patient had a complete cerebral infarct. All cases of cerebral infarct were confirmed with computed tomography scan or magnetic resonance imaging. The clinical profile supported an embolic mechanism. The early recognition and management of this complication can influence the prognosis of these patients and therefore emphasize the importance of the monitoring of the neurological function in the hemodynamic department.

Adult↗