Volatile organic compounds in the area of Madrid: a chemometrical approach.

Multivariate techniques have been applied to the set of data obtained after one year sampling of volatile organic compounds (VOCs), including volatile aldehydes in the area of Madrid in order to evaluate the possible correspondence among groups of analysed compounds, as far as modelling of different emission sources in relation to location and season. The measurements were carried out at four sites in Madrid, characteristic for urban and suburban areas. Additionally, as reference, a rural area 100 km far from the city was considered. Results of correlation analysis, factor and cluster analysis are presented. Higher correlations were found between variables related with traffic emissions. Factor analysis results showed two main significant variables related to anthropogenic and biogenic emissions respectively. In relation to cluster analysis, samples were grouped according to sampling site and seasonal variations.

Chemometric study of selected polychlorinated biphenyls in ambient air of Madrid (Spain).

Monthly ambient air and surface soil samples were taken for analysis in the outskirts of Madrid in an open urban area from November 1998 to October 1999. Thirty-one polychlorinated biphenyl congeners were analysed, selection being done according to their abundance in environmental samples. The present work shows the results obtained when factor analysis (FA) and cluster analysis were applied to concentration data of seventy-one ambient air samples (polyurethane foam plugs and filters). Both chemical parameters (concentrations and total suspended particulate) and two meteorological parameters (temperature and wind velocity) were determined weekly during the sampling period. A bivariate correlation analysis was previously performed to estimate relationships between PCBs and, also between soil and filter medium.

Genetic heterogeneity within ulcerative colitis determined by an interleukin-1 receptor antagonist gene polymorphism and antineutrophil cytoplasmic antibodies.

BACKGROUND: Although there is strong evidence implicating genetic predisposition in the pathogenesis of the chronic inflammatory bowel diseases, the number and identity of susceptibility genes remain uncertain. Cytokine genes are tentative candidate loci, but data regarding association studies in different populations are conflicting. AIMS: To determine potential associations of interleukin-1 receptor antagonist (IL-1ra), tumour necrosis factor alpha (TNF alpha), and tumour necrosis factor beta (TNF beta) gene polymorphisms with ulcerative colitis or subsets of ulcerative colitis in a Spanish population. METHODS: Genotyping for IL-1ra, TNF alpha and TNF beta gene polymorphisms was performed by the polymerase chain reaction in 95 patients with ulcerative colitis and 74 healthy controls. A variable number of tandem repeats (VNTR) in the IL-1ra gene, and a single base pair polymorphism in the TNF alpha gene promoter region (-308) and in the first intron of the TNF beta gene were analysed. Anti-neutrophil cytoplasmic antibodies (ANCA) were detected using an indirect immunofluorescence assay. RESULTS: There were no significant differences between ulcerative colitis patients and controls in either polymorphism analysed, nor between ulcerative colitis subgroups as a function of the clinical disease pattern. However, when stratified by their ANCA status, perinuclear ANCA (p-ANCA) ulcerative colitis showed an increased frequency of the genotype 1,2 of the IL-1ra gene compared with ANCA-negative ulcerative colitis (52% versus 28%; P = 0.02, Pcorr = 0.1). Furthermore, p-ANCA ulcerative colitis had a statistically significant increase of this genotype compared with cytoplasmic ANCA (c-ANCA)/ANCA-negative ulcerative colitis (52% versus 26.5%; P = 0.01, Pcorr = 0.05). CONCLUSIONS: In the Spanish population studied, the polymorphisms analysed in the IL-1ra, TNF alpha and TNF beta genes are unlikely to be important in the overall susceptibility to ulcerative colitis. However, the combination of a subclinical (p-ANCA) and a genetic (IL-1ra gene) marker identified a distinct ulcerative colitis subgroup (p-ANCA; IL-1ra genotype 1,2). These findings provide further evidence of genetic heterogeneity within ulcerative colitis, and support the concept that ANCA may represent a subclinical marker of genetic heterogeneity.

Distribution of volatile organic compounds in Madrid (Spain).

From November 1995 to October 1996, airborne concentrations of VOCs were measured in the Madrid area to study the organic pollution in general, and the correlation between different pollutants in relation to such parameters as location and season. Mean concentrations for up to 90 compounds were measured at four test sites, including both urban and suburban areas. At the urban sites, maximum concentrations occurred in the autumn and winter, whereas minimum concentrations were reached in summer and spring. Similar changes were obtained for the less contaminated site located in the SE of the city, whereas a different pattern was found at the site in the NW of the city due to meteorological aspects. Mean levels of hydrocarbons in Madrid were quite similar to those found in other European cities. Chemometrical techniques were applied to the set of data in order to assess the influence of such factors as traffic, temperature and seasonal variations on the VOC levels.

Measurements of selected PCBs in open urban ambient air of Madrid (Spain): First results.

The focus of this study was to characterize the concentration levels of selected PCBs and compare them to compiled data in order to contribute to the international database. The sampling site is located in the outskirts of Madrid and can be considered an open urban area. 32 samples of air were taken from February 1998 to June 1998 by using a high volume air sampler. Glass fiber filters and polyurethane foam (PUF) were used to collect the paniculate and gas phase material, respectively. PUF plugs were Soxhlet extracted and filters were ultrasonically extracted by using pesticide-grade hexane and dichloromethane, respectively. The cleanup procedure was carried out on a florisil column with hexane and hexane/dichloromethane as elution solvents. GC/MS in a selected ion monitoring mode was used for quantification and 29 selected PCBs congeners were analyzed.

[antineutrophil cytoplasmic autoantibodies in inflammatory bowel disease]. / Anticuerpos anticitoplasma de neutrófilo en la enfermedad inflamatoria del intestino.

BACKGROUND: The aim of the present study was to determine the prevalence and diagnostic usefulness of antineutrophil cytoplasmic antibodies (ANCA) in a Spanish population of patients with inflammatory bowel disease from the province of Tarragona. PATIENTS AND METHODS: One hundred and fifty-six sera obtained from 116 patients with inflammatory bowel disease (75 ulcerative colitis and 41 Crohn's disease) and 40 healthy controls were tested using an indirect immunofluorescence assay. RESULTS: ANCA were detected in 65% of patients with ulcerative colitis but in only 12% of patients with Crohn's disease (p < 0.01), and 2.5% of control subjects (p < 0.01). The overall sensitivity of the test for the diagnosis of ulcerative colitis was 65% with a specificity of 88% and a positive predictive value of 91%. Among patients with ulcerative colitis there was no relationship between the presence or titre of ANCA and the duration, the clinical course, the extent, the disease activity or the need for medical treatment. CONCLUSIONS: In the population studied, ANCA occur more commonly in ulcerative colitis than in Crohn's disease, as reported in other populations. Their determination in patients with inflammatory bowel disease may be useful to differentiate ulcerative colitis from Crohn's disease.

Antineutrophil cytoplasmic antibodies in relatives of patients with inflammatory bowel disease.

BACKGROUND: The occurrence of antineutrophil cytoplasmic antibodies (ANCA) has been reported more frequently than expected in healthy first-degree relatives of patients with ulcerative colitis, suggesting that these antibodies may represent a subclinical marker of genetic disease susceptibility. AIM: To determine the prevalence of ANCA in unaffected first-degree relatives of inflammatory bowel disease patients in a Spanish population. METHODS: Three hundred and seventy sera obtained from 80 patients with inflammatory bowel disease (55 ulcerative colitis, 25 Crohn's disease), 217 unaffected first-degree relatives (157 from ulcerative colitis and 60 from Crohn's disease patients), 62 healthy controls, and 11 celiac disease patients were tested using an indirect immunofluorescence assay. RESULTS: Antibodies were detected in 64% of patients with ulcerative colitis but in only 12.5% of patients with Crohn's disease. ANCA were seldom present in their unaffected first-degree relatives (4.6%), control subjects (1.6%), and celiac disease patients (0%). CONCLUSIONS: In the Spanish population studied, antineutrophil cytoplasmic antibodies occur more commonly in ulcerative colitis than in Crohn's disease, as reported in other Caucasian populations. Moreover, their presence is not increased in their first-degree relatives. These findings indicate that ANCA are not a subclinical marker of genetic susceptibility to inflammatory bowel disease in this population.

Effects of KClO4 in propylthiouracil-hypothyroid rats.

In this study we investigated further the antigoitrogenic effect of ClO4 in rats on a low iodine diet (LID) and 6-propyl-2-thiouracil (PTU). The thyroid weight of rats on the mixed goitrogen was initially similar to that of animals on PTU, decreasing to values obtained in rats treated with ClO4 alone by 10 days. Despite the differences in thyroid weight, rats treated during an identical period with PTU or mixed goitrogen develop hypothyroidism to a comparable degree as far as can be assessed by the thyroidal 127I content, plasma T4, T3 and TSH concentrations, and pituitary TSH content. Moreover, it was observed that there were differences in plasma insulin and glucose levels in these hypothyroid animals. The plasma insulin and glucose levels of rats on PTU are comparable to those found in control rats. In rats on mixed goitrogen, both plasma insulin and glucose levels are initially maintained within the normal ranges, and then decline over the subsequent days of treatment. Within the treatment period studied here, plasma insulin and glucose levels were higher for rats on PTU than for animals on ClO4, PTU + ClO4, or thyroidectomized (Th) animals. We have obtained further evidence of the hypothyroid state of rats on these goitrogen regimens based on measurements of pituitary and plasma GH levels and liver mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD). The PTU-treatment decreased the liver alpha-GPD activity to a comparable degree to that of mixed goitrogen. Moreover, both PTU + ClO4 and PTU-treatment resulted in a state of hypothyroidism intense enough to induce effects on growth, and plasma and pituitary GH levels comparable to that of Th animals. However, the values for rats on mixed goitrogen appear to be below the PTU data. The present findings appear to be consistent with the view that TSH is not the unique factor determining the size of the resulting goitre. The results are discussed in relation to the hypothesis that: 1) the antigoitrogenic effect of ClO4 could be associated with changes in the ability of the thyroid tissue to bind TSH, or with a step beyond TSH binding, and 2) the different endocrine and metabolic states of rats on PTU or PTU + ClO4, shown by their different plasma insulin, GH and glucose levels, may play an important role in determining the thyroid weight response to TSH.