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Biomedical subjects

G Font

Publications and source records attributed to G Font.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cancer mortality and exposure to chemical carcinogens in the work place: an ecological study in the Valencian Community, Spain (1981-1995).

To evaluate the geographical distribution of the mortality from malignant tumours in relationship with exposure to chemical carcinogens in the work place, and to asses the possible association between these questions and the percentage of population employed in certain high-risk sectors, an ecological study in the Valencian Community (VC), Spain was carried out. Age-adjusted mortality rates for the total number of malignant tumours, lung, bladder, lymphomas and leukaemia during the periods 1981-1985 and 1991-1995 were calculated for the 34 geographical areas. The percentage of population in each area working in sectors in which they may be exposed to chemical carcinogens was obtained. The relationship between mortality on-the-job exposure was studied using linear regression methods. Large differences in cancer mortality were seen. In men, the geographical pattern was very stable and reveals a significant association with the distribution of certain high-risk jobs. Statistically significant positive correlations (p < 0.001) were found between cancer mortality and the percentage of the population working in metal, wood and furniture sectors. In contrast, a negative and statistically significant (p < 0.001) correlation was observed between cancer mortality and the percentage of the population working in agriculture. In conclusion, although the variability in cancer mortality in men was significantly associated with some occupational sectors in the VC, caution is needed when drawing conclusions about causation from ecological studies.

Agriculture↗
PubMed1999

Matrix solid-phase dispersion microextraction and determination by high-performance liquid chromatography with UV detection of pesticide residues in citrus fruit.

A multiresidue method based on matrix solid-phase dispersion (MSPD) microextraction was studied to determine the carbamate, benfuracarb, and urea insecticides, diflubenzuron, flufenoxuron hexaflumuron and hexythiazox, used in control of citrus pests. Optimisation of different parameters, such as the type of solid support for matrix dispersion, elution solvents and the clean-up step were carried out. The method used 0.5 g of orange sample, C8 bonded silica as MSPD sorbent and dichloromethane as eluting solvent. Recoveries, at spiked concentrations below the maximum residue levels established by Spanish Government, were between 74 and 84% with relative standard deviations ranging from 2 to 4%. The limits of quantification were from 0.15 to 0.25 microgram/g using high-performance liquid chromatography with UV detection at 200 nm. The method may be useful as a screening protocol for the determination of these newly developed pesticides in citrus samples.

Benzamides↗
PubMed1999

Toxicological assessment of recombinant xylanase X(22) in wine.

Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wine). Body weight, food and fluid intake, urinalysis, and hematology data were obtained. Postmortem examinations and histopathology by both light and electron microscopy were performed. According to the results of this study, no adverse effects were detected by oral administration of X(22).

Allergens↗
PubMed1997

Dissipation and distribution of atrazine, simazine, chlorpyrifos, and tetradifon residues in citrus orchard soil.

An environmental fate study was conducted in a citrus orchard plot in València (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0-0.05, 0.05-0.22, 0.22-0.42, and 0.42-0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlorpyrifos, and 18 for tetradifon. The distribution through the soil profile shows that the pesticide concentrations were always highest in the upper layer (0-0.05 m) of soil, and that atrazine was the most mobile of all the four pesticides investigated.

Chlorpyrifos↗
PubMed1996

Optimization of a matrix solid-phase dispersion method for the analysis of pesticide residues in vegetables.

A multiresidue method based on matrix solid-phase dispersion (MSPD) is studied to determine chlorfenvinfos, chlorpyrifos, fenarimol, iprodione, procimydone, propiconazole, tetradifon, triadimefon and vinclozolin in artichokes, green beans, lettuces and tomatoes. Alumina, silica and Florisil were assessed as extracting phases, and the extracts from Florisil were the cleanest. To facilitate manual extraction, sand was added to the sample together with the dispersing phase. Three eluting systems were then studied, and dichloromethane proved to be the best. Further purification can be performed using solid-phase cleanup after diluting extracts with aqueous solutions. Octyl- and octadecyl-silica, modifications of the aqueous diluted extracts and several eluting solvents were studied. Determination was done by capillary gas chromatography (GC) with electron-capture detection, and confirmed by GC-MS using the electron impact mode and the selected ion monitoring. The proposed MSPD method was used to analyze 48 samples taken in the course of a year. Procymidone, vinclozolin, chlorpyrifos and chlorfenvinfos were identified in 10 samples at levels below the maximum residue levels allowed by the Spanish Government.

Gas Chromatography-Mass Spectrometry↗
PubMed1996

Current developments in the analysis of water pollution by polychlorinated biphenyls.

A review and discussion of the analytical developments of the last 10 years in the determination of polychlorinated biphenyls (PCBs) in water are presented, including sample treatment, clean-up, identification and determination. Some of the most significant advances have occurred in the area of sample preparation, such as the increased adoption of solid-phase extraction and on-line techniques and the chromatographic separation of PCB congeners, principally by mass spectrometry. Special attention is focused on applications to real samples.

Chromatography, Gas↗
PubMed1995

Solid-phase extraction on C18 in the trace determination of selected polychlorinated biphenyls in milk.

The utility of solid-phase extraction with octadecylsilica for determining fifteen polychlorinated biphenyl (PCB) congeners from milk samples was examined. Recoveries higher than 80% and relative standard deviations better than 10% were obtained for PCBs from different kinds of milk (whole, skimmed, 2%, powdered, breast and evaporated). A comparison with other procedures was made. The described method provides better detection limits than those attainable with the liquid-liquid extractions currently used as standard methods, when capillary gas-liquid chromatography is used for the final determination. A study of the separation was also performed using six different fused-silica capillary columns and an electron-capture detector.

Animals↗
PubMed1993

Solid-phase extraction in multi-residue pesticide analysis of water.

The determination of pesticides in water is fundamental to the solution of environmental problems as natural waters are usually contaminated with a large number of pesticides. The selection of an isolation and/or concentration technique depends largely on the class of pesticides to be determined. It is often necessary to determine simultaneously a wide variety of compounds in a water sample. Application of solid-phase extraction techniques offers a solution. The mechanisms of solid-phase extraction, types of sorbents and their application to multi-residue pesticide analysis are reviewed.

Chromatography↗
PubMed1993

Evaluation of a solid-phase extraction system for determining pesticide residues in milk.

A simple and rapid procedure based on reversed solid-phase extraction with octadecylsilica was developed for determining chlorinated pesticide residues in milk. The need for an agent that breaks the fat globules was first investigated and the method variables were optimized on whole homogenized milk (3.6% fat content). Recovery experiments performed for 26 organochlorine pesticides at levels of 3-40 micrograms/l gave > 80% recoveries for all the compounds. The method was validated and evaluated by comparison with two widely used liquid-liquid extraction methods. The performance was checked by analysis of a certified standard with natural low endogenous levels (CMR 187) and different kinds of milk (skimmed, 2%, powdered, evaporated and condensed) spiked with the 26 pesticides. The procedure was used to analyse 45 commercial milks in which the presence of organochlorine residues had been detected. The proposed method offers advantages such as low cost and simplicity and the fact that the extracts obtained do not require a purification step.

Animals↗
PubMed1991

Determination of triazines and organophosphorus pesticides in water samples using solid-phase extraction.

Octadecyl (C18)-bonded porous silica was evaluated for the extraction of triazine and organophosphorus pesticides from natural water. The extraction results showed an effective performance when 11 of water was passed through small glass columns containing 500 mg of 50-100-microns C18 bonded porous silica. The adsorbed compounds were removed with ethyl acetate, evaporated to 200 microliters and determined by gas chromatography. The overall average recoveries were greater than 85% except for dimethoate and trichlorfon. Application of this procedure to the analysis of natural water samples gave results that agree well with those obtained by solvent extraction methods.

Chromatography, Gas↗
PubMed1991

Doppler evaluation of the fetoplacental circulation in the latent phase of preterm premature rupture of membranes.

Blood velocity waveform analysis by pulsed Doppler ultrasonography in preterm premature rupture of membranes is described. Reduced amounts of amniotic fluid did not impair determination of the resistance indices from the umbilical artery. Good results were obtained from the internal carotid artery in 82% of cases. Failure in measurements at the internal carotid artery occurred when fetal head engagement prevented good study planes. Ninety-three percent of umbilical artery determinations fell within the normal limits for our control population as did 89.2% of those at the internal carotid artery. No differences in the resistance indices could be attributed to the length of the latent period in prematurely ruptured membranes or subclinical chorioamnionitis. Therefore, if a mother or fetus has an underlying condition that affects fetoplacental circulation, the resulting abnormal blood velocity waveform should reflect this condition rather than the effect of ruptured membranes.

Blood Flow Velocity↗
PubMed1990

Liquid chromatographic determination of hydralazine in human plasma with 2-hydroxy-1-naphthaldehyde pre-column derivatization.

A selective and sensitive high-performance liquid chromatographic method is described for determination of hydralazine and its metabolites in human plasma. The method involves pre-column derivatization with 2-hydroxy-1-naphthaldehyde at pH 1.2. The reaction product and Methyl Red used as internal standard are extracted into dichloromethane and chromatographed in the reversed-phase mode on an ODS-2 column using acetonitrile-aqueous triethylamine phosphate buffer (80:20, v/v) at pH 3 as eluent. The plasma calibration curve of hydralazine is linear in the concentration range 10-500 ng ml-1. The detection limit is 1 ng ml-1 and the relative standard deviation is less than 2.4. In vivo pharmacokinetics of hydralazine in two volunteers after oral administration of 50 mg of the drug is studied using the proposed LC method.

Azo Compounds↗
PubMed1990

Aldicarb residues in citrus soil, leaves and fruits.

Aldicarb was applied to the soil of Late Valencia orange field plots. A comparative study between four analytical methods is reported, the NPD-gas chromatography method being the best choice. The work also reports the study of accumulation and persistence of aldicarb and its biologically active metabolites in the soil, leaves and fruits (rind and pulp, separately). Residue content, at the ppb level, was found in the order leaves much greater than rind greater than pulp. Carbamate was found to accumulate mainly in its oxidized forms. Residues had reached a maximum level in about 90 days after application.

Aldicarb↗