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B Sinués

Publications and source records attributed to B Sinués.

16 recordsLinked to original sources
PubMed1999

Five caffeine metabolite ratios to measure tobacco-induced CYP1A2 activity and their relationships with urinary mutagenicity and urine flow.

To choose a sensitive protocol to discriminate populations exposed and not exposed to inducers, five urinary metabolite ratios (MRs) [MR1 (17X + 17U)/137X, MR2 (5-acetylamino-6-formylamino-3-methyluracil [AFMU] + 1X + 1U)/17U, MR3 (17X/137X), MR4 (AFMU + 1X + 1U + 17X + 17U)/137X, and MR5 (AFMU + 1X + 1U)/17X] were calculated in 4-5 h and 0-24 h urine samples after caffeine intake. One hundred twenty-five healthy volunteers (59 nonsmokers and 66 smokers) were included in the study. All ratios showed a log-normal distribution. MR2 in the two time intervals was the only ratio nondependent on the urine flow. Differences between nonsmokers and smokers could be detected with all ratios at 4-5 h. However, only MR2 and, to a lesser extent, MR5 allowed the discrimination of higher cytochrome P450 1A2 (CYP1A2) activity in smokers in the 0-24 h sample. Although smokers had increased urinary mutagenicity in relation to nonsmokers, a significant association between MRs and urine mutagenicity was observed only with MR2 in the 4-5 h interval; this ratio/time schedule being that of higher association with tobacco consumption. The most flow-dependent ratios, MR1, MR3, and MR4, were closely correlated with each other at the two intervals. The flow dependency profile of each ratio may explain their different power to indicate both tobacco exposure and tobacco-derived mutagenicity. In conclusion, MR2 in the period of 4-5 h after caffeine intake seems preferable, especially at high urine flow rates.

Adolescent↗
PubMed1995

Six mutagenicity assays in exposure biomonitoring of patients receiving carbamazepine for epilepsy or trigeminal neuralgia.

The mutagenic potential of carbamazepine (CBZ) therapy has been studied in 37 patients undergoing long-term treatment with this drug. Of the total group, 23 patients suffered from epilepsy and 14 from trigeminal neuralgia. Thirty-one healty subjects served as controls. Six mutagenicity assays with different end-points were performed. The possible cytogenetic alterations were evaluated by analyzing sister-chromatid exchange frequencies (SCE), chromosome aberrations (CA), micronuclei (MN), proliferation indices (PRI), and mitotic indices. The Salmonella assay with and without microsomal activation served to measure urinary mutagenicity. The results show that CBZ leads to an increase in SCE (p < 0.01) and PRI (p < 0.05) but had no effect on the other cytogenetic parameters. CBZ was negative in the urine mutagenicity test. Plasma levels of total CBZ, free CBZ and CBZ-10,11-epoxide did not correlate with the cytogenetic alterations. Even though folic acid and gamma-glutamyltranspeptidase were significantly different in patients and controls, there was no significant association between these values and SCE or PRI. Patients with epilepsy and those with trigeminal neuralgia did not differ with respect to the end-points analyzed.

Adolescent↗
PubMed1994

Thioether excretion, urinary mutagenicity, and metabolic phenotype in smokers.

In 81 healthy individuals (51 smokers and 30 nonsmokers) biological indicators of internal exposure to electrophiles derived from tobacco smoke through metabolism were evaluated. Subgroups of smokers have been established in relation to the amount and type of tobacco smoked. Acetylator and hydroxylator phenotypes have been used as biomarkers of genetically determined susceptibility to cancer development. Urinary concentrations of thioethers (UT) and mutagenicity, with S9 mix for microsomal activation (MI-S9), were higher in smokers in relation to the level of tobacco consumption, but not to the type of tobacco. The "Slow acetylators-rapid oxidizers" category was not significant from the "rapid acetylators-rapid oxidizers" for values of UT and MI-S9. Data suggest that the biomarkers of exposure used in this study lack the necessary specificity to ascertain genetically determined susceptibility to cancer induced by tobacco smoking.

Acetylation↗
PubMed1993

Apoprotein A and A-I profiles in subretinal fluid.

Previous reports have described the presence of apoproteins A in subretinal fluid (SRF). We studied the presence of total apoprotein A (apo A) and apoprotein A-I (apo A-I), using the method described by Laurel in SRF and its levels in serum in 20 patients with retinal detachment. By this method we can quantify the concentrations of apoproteins in SRF. All cases showed the presence of these apoproteins in SRF. The mean +/- standard deviation obtained was 78.7 +/- 26.94 mg/dl and 173.35 +/- 30.08 mg/dl for total apo A in SRF and serum respectively. For apo A-I these values were 32.62 +/- 14.36 mg/dl in SRF and 123.4 +/- 24.11 mg/dl in serum. We found no correlation between levels of total apo A and apo A-I in SRF and its levels in serum. Statistical differences were found between apo A-I content in SRF from detachments with the size of 3 quadrants and that of 1 and 2 quadrants but not between 3 and 4 quadrants. When the detachment affected 1 and 2 quadrants the concentrations of apo A-I were statistically lower. No statistical differences were found between concentrations of total apo A and apo A-I in SRF and the duration or presence of PVR in the detachments. These findings suggest that the outer blood retinal barrier is preserved during rhegmatogenous retinal detachment.

Adult↗
PubMed1993

Levels of vancomycin in aqueous humor after topical eye drops administration.

Vancomycin is an antibiotic which is especially active against Gram positive bacteria. At present, numerous infections of the anterior segment of the eye are caused by the Staphilococcus aureus and epidermis. Strains which are resistant to methicilin are more and more frequent and for this reason Vancomycin is becoming the antibiotic of choice to combat these infections since no resistance of the Staphilococcus to it has been demonstrated. The authors evaluated the levels of Vancomycin in aqueous humor after the administration of topical eye-drops. For the first two hours after the last administration, levels of 0.52 micrograms/ml were detected. These inhibit the growth of the majority of bacteria sensitive to Vancomycin. Between two and four hours, the levels decreased to 0.15 micrograms/ml; these are therapeutic levels for a large number of Gram positive bacteria. From four hours after the last administration, these levels are undetectable. Due to the success of its penetration, topical administration of Vancomycin should be considered as a therapeutic modality against infections by gram positive bacteria of the anterior segment. The ideal guideline for administration would be one drop every two hours, especially if the infection is severe. In this way, subconjunctival injection could be avoided.

Anterior Eye Segment↗
PubMed1992

Urinary mutagenicity and N-acetylation phenotype in textile industry workers exposed to arylamines.

Primary aromatic amines have been identified epidemiologically as human carcinogens. It has been suggested that the target organ affected by aromatic amines is dependent on the rate of metabolic activation. Epidemiological studies have shown an association between low acetyl transferase activity and bladder cancer risk. On this basis, our working hypothesis was that the slow acetylators could follow in a higher extent the metabolic pathway independent of N-acetylation, leading to the excretion of conjugates of electrophyles with glucuronic acid. The instability of these glucuronides could be responsible for the association between arylamine-induced bladder cancer and slow acetylator phenotype. A total of 153 individuals were included in this study: 70 exposed to arylamines (working in textile industry) and 83 nonexposed. The following parameters were determined in urine: mutagenic index in the absence of metabolic activation, S9; mutagenic index in the presence of S9; and the mutagenic index after incubation of the urine with beta-glucuronidase. All individuals were phenotyped according to their capacity of N-acetylation by using isoniazid as drug test. The results show that the mutagenic index after incubation of the urine with beta-glucuronidase is statistically higher in exposed subjects when compared with nonexposed individuals (P less than 0.001), this parameter being statistically higher among exposed subjects who were slow acetylators than among rapid metabolizers, independent of the fact that they were smokers or nonsmokers. There were no significant differences between groups for the mutagenicity in urine not incubated with beta-glucuronidase.

Acetylation↗
PubMed1991

Sister chromatid exchanges, proliferating rate index, and micronuclei in biomonitoring of internal exposure to vinyl chloride monomer in plastic industry workers.

The frequency of micronuclei (MN), sister chromatid exchange (SCEs), and the proliferating rate index in peripheral blood lymphocytes from 93 individuals were measured. Fifty-two of the individuals were workers in the plastics industry where they were exposed to vinyl chloride monomer while the remaining 41 individuals served as a control group. In our results, an increase of SCEs and MN, as well as inhibited cell kinetics, was observed in the group of exposed workers. Of the tests used, SCE was found to be the most sensitive endpoint for indicating a biological response. However, since methods for restricting the MN analysis to only cells at risk (i.e., second generation interphase cells) were not used, this statement requires verification.

Adolescent↗
PubMed1990

[Erythrocyte glutathione and urinary thioethers in smokers].

The carcinogenic mechanism of smoking is related with the production of electrophilic reactants and their possible covalent binding with DNA. On the other hand, there are detoxifying mechanisms such as glutathione-S-transferase, which results in mercaptopuric derivatives that are excreted in the urine. The integrity of the erythrocyte membrane is maintained by reduced glutathione among other factors. In the present study, the concentrations of erythrocyte reduced glutathione (GSH) and urinary thioethers (UT) were measured in a sample of 81 subjects divided in two groups. Group I: 30 nonsmokers; group II: 51 smokers, subdivided in group IIA (26 individuals smoking 10-20 cigarettes/day) and group IIB (25 individuals smoking more than 20 cigarettes/day). In the present study, the usefulness of GSH and UT as markers of collective internal contamination and of individual risk regarding tobacco exposure were evaluated. A higher concentration of GSH was found in smokers than in nonsmokers (F = 6.84, p less than 0.02). Regarding VT elimination, a significant increase in these parameters was found in association with the grade of smoking (p less than 0.05). They were higher in the subjects from the subgroup IIB than in the subgroup IIA (moderate smokers).

Adult↗
PubMed1990

Chromosome aberrations and urinary thioethers in smokers.

Chromosome aberrations, classified as chromosome- and chromatid-type aberrations, were evaluated in 94 individuals. The concentration of thioethers in the urine was also determined. The sample consisted of 41 non-smokers (control group) and 53 smokers, 25 smoked 10-20 cigarettes/day (subgroup IIA) and 28 smoked more than 20 cigarettes/day (subgroup IIB). Our aim was to perform internal dosimetry on smokers using a cytogenetic test, and a test for urinary excretion of thioethers, in order to determine the relation between these 2 methods of dosimetry. Our results show a higher frequency of chromosome aberrations (p less than 0.0001) and a higher excretion of urinary thioethers (p less than 0.0001) in smokers as compared to non-smokers. However, linear regression between these parameters was not statistically significant. In view of the variation between different individuals with regard to the amount of urinary thioethers, it seems more accurate to perform the biomonitoring of smoking by analyzing chromosome aberrations.

Adolescent↗
PubMed1990

Cytogenic effects of diatrizoate and ioxaglate on patients undergoing excretory urography.

Possible cytogenic alterations due to radiologic contrast medium in patients undergoing a common radiologic examination is studied. Two groups of 20 patients each were used. Group I consisted of patients undergoing excretory urography, using sodium and meglumine diatrizoate as contrast. A different agent, sodium and meglumine ioxaglate, was used with group II. Three blood samples were taken from each patient before urography, immediately after urography, and 1 week later. The frequency of sister chromatid exchanges (SCE) and chromosomal aberrations (CA) were found to increase significantly in the B samples from both groups, that of group I being higher (P less than .01 compared with P less than .05). Furthermore, these alterations were found to persist in the C samples from group I. No modification of the Proliferating Rate Index (PRI) was found. The osmolarity or other components of the contrast media studied could be involved in the process. The results indicate that ioxaglate produces less cytogenic damage than diatrizoate.

Adult↗
PubMedDate not supplied

Apoprotein B in subretinal fluid.

We studied the presence of apolipoprotein B (apo B) by immunoelectrophoresis in subretinal fluid (SRF) and serum from 15 rhegmatogenous retinal detachments and 5 retinal detachments with proliferative vitreoretinopathy (PVR). Apo B concentration +/- standard deviation was 1.49 +/- 1.06 mg/dl in SRF and 108.41 +/- 40.22 mg/dl in serum. Only in four cases was apo B not detected in SRF. We found no significant correlation between apo B concentrations in SRF and apo B levels in serum. We did not find a positive correlation between apo B concentrations in SRF and the duration and size of the detachments. There was no statistical relationship between the presence of PVR and apo B levels. This phenomenon suggests the preservation of the outer blood retinal barrier during rhegmatogenous retinal detachment.

Adult↗