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Biomedical subjects

M Torrent

Publications and source records attributed to M Torrent.

At least 19 recordsLinked to original sources
PubMed2006

Early exposure to dichlorodiphenyldichloroethylene, breastfeeding and asthma at age six.

Our aims were to assess association of dichlorodiphenyldichloroethylene (DDE) with childhood asthma measured up to age 6 and the effect of DDE on the protective effect of breastfeeding on asthma. In addition, we attempted to assess the relevant time-window of DDE exposure (i.e. at birth or at 4 years). All women presenting for antenatal care in Menorca, Spain over a 12-month period beginning in mid-1997 were invited to take part in a longitudinal study that included a yearly visit. Four hundred eighty-two children were enrolled and 462 provided complete outcome data after 6.5 years of follow-up. Organochlorine compounds were measured in cord serum of 402 (83%) infants and in blood samples of 285 children aged 4. We defined asthma as the presence of wheezing at age 6 and during any preceding year or doctor-diagnosed asthma, and used skin prick test at age 6 to determine atopic status. Results At birth and 4 years of age, all children had detectable levels of DDE (median 1 ng/mL and 0.8 ng/mL, respectively). From birth to age 4, the mean DDE level among children with artificial feeding decreased by 72%, while among breastfed children it increased by 53%. Diagnosed asthma and persistent wheezing were associated with DDE at birth [odds ratio (OR) for an increase in 1 ng/mL, OR=1.18, 95% confidence interval (95% CI)=1.01-1.39 and OR=1.13, 95% CI=0.98-1.30, respectively], but not with DDE at 4 years. Neither breastfeeding nor atopy modified these associations (P>0.3). Breastfeeding protected against diagnosed asthma (OR=0.33, 95% CI=0.08-0.87) and wheezing (OR=0.53, 95% CI=0.34-0.82) in children with low and high DDE levels at birth. Conclusion In a community without known dichlorodiphenyltrichloroethane environmental releases, this study strengthens the evidence for an effect of DDE on asthma by measuring the disease at age 6 and does not support the hypothesis that DDE modifies the protective effect of breastfeeding on asthma.

Asthma↗
PubMed2004

Concentrations and determinants of NO2 in homes of Ashford, UK and Barcelona and Menorca, Spain.

UNLABELLED: This study examined indoor nitrogen dioxide (NO2) concentrations in Ashford, Kent (UK), Menorca Island and Barcelona city (Spain) and the contribution of their most important indoor determinants (e.g. gas combustion appliances and cigarette smoking). The homes examined (n = 1421) were those from infants recruited for the Asthma Multicentre Infants Cohort Study, which aimed to assess, using a standard protocol, the effects of pre- and post-natal environmental exposures in the inception of atopy and asthma. Indoor NO2 was measured using passive filter badges placed on a living room wall of the homes for between 7 and 15 days. Homes in the three centers had significantly different concentrations of indoor NO2, with those in Barcelona showing the highest levels (median NO2 levels: 5.79, 6.06 and 23.87 p.p.b. in Ashford, Menorca and Barcelona, respectively). Multiple regression analysis showed that the principal indoor determinants of NO2 concentrations in the three cohorts were the heating/cooking fuel used in the house (gas fire increased average NO2 concentrations by 1.27-fold and gas cooker by 2.13 times), parental cigarette smoking and season of measurement. Those variables significantly related to indoor NO(2) accounted for 23, 14 and 39% of the variation in indoor NO2 concentration in Ashford, Barcelona and Menorca, respectively. In all the cohorts combined, 52% of the variation could be explained in this way. Although outdoor NO2 was not measured concurrently, its additional contribution was estimated. In conclusion, despite differences in indoor NO2 mean concentrations probably reflecting different outdoor NO2 level, home factors affecting indoor NO2 values and their specific contributions were constant across the three cohorts. PRACTICAL IMPLICATIONS: This study found that principal determinants associated to indoor NO2 in three different sites of Europe: Ashford (UK), Barcelona and Menorca (Spain) were the energy source present in the home and cigarette smoking, despite these areas presented different climates, levels of outdoor contamination, housing characteristics and ventilation behavior. It is suggested that interventions in homes of these three centers will need to address principally cigarette smoking and gas combustion appliances. These latter factors require institutional intervention, while cigarette smoking mainly require personal changes.

Adult↗
PubMed2001

Maternal atopy and parity.

BACKGROUND: Family size and high birth order were related to the prevalence of hayfever and positive skin prick test. However, this association may be explained by maternal atopy. We examined the relationship between maternal atopy and the number of offspring in three European cohorts of pregnant women. METHODS: The mothers and their children (n = 1487) were recruited for the Asthma Multi-centre Infants Cohort Study (AMICS). The three concurrent cohorts (Ashford, Kent (UK); Menorca island (Spain) and Barcelona city (Spain) followed the same research protocol. Maternal and paternal atopy was identified by skin prick tests at different times at the three centres. RESULTS: Maternal atopy was inversely related to the number of offspring, an association which occurred in each of the three cohorts and remained when atopy was defined separately for individual allergens (a positive response to testing with either Der p 1 or grass pollen) and which was not confounded by maternal age, smoking nor social class (the adjusted odds ratios were 0.71, 0.79 and 0.26 for increasing number of offspring, P = 0.002). Neither maternal asthma (P = 0.43) nor paternal atopy (P = 0.58) were associated with the number of offspring. Maternal atopy was not related to reproductive outcomes. CONCLUSIONS: The association between maternal atopy and parity challenges the role of family size on child atopy, which should be studied in other populations.

Adult↗
PubMed2001

Frequency of multiple sclerosis in Menorca, Balearic islands, Spain.

OBJECTIVE: To establish prevalence and incidence of multiple sclerosis (MS) in Menorca (Balearic Islands, Spain; population: 67,009). METHODS: An extensive epidemiological study was undertaken using all available information sources. Patients were classified according to Poser's criteria. RESULTS: The prevalence rate of definite and probable MS was 68.6/100,000 (95% confidence interval 50.3-91.6). The incidence rate was 3.4/100,000/year (95% CI 2.2-5.3). The time lag between the first symptom and diagnosis was 10.2 years for patients with disease onset before 1987 and 2.1 years for patients with onset between 1987 and 1996. CONCLUSION: Menorca's population has a moderately high MS risk, with a prevalence rate the highest reported for a Spanish region.

Adult↗
PubMed1999

Identification of dimethylbenzimidazole axial coordination and characterization of (14)N superhyperfine and nuclear quadrupole coupling in Cob(II)alamin bound to ethanolamine deaminase in a catalytically-engaged substrate radical-Cobalt(II) biradical state.

Cobalt(II)-(14)N superhyperfine and (14)N nuclear quadrupole couplings in cryotrapped free and ethanolamine deaminase-bound cob(II)alamin have been characterized in the disordered solid state by using X-band electron spin-echo envelope modulation (ESEEM) spectroscopy. Enzyme-bound cob(II)alamin was cryotrapped after formation by substrate-initiated, thermally activated cleavage of the cobalt-carbon bond of adenosylcobalamin. Free dimethylbenzimidazole axial base-on cob(II)alamin was formed by photolysis of the corresponding adenosylcobalamin and cryotrapped in glycerol-aqueous glass. Three-pulse ESEEM experiments were performed by using microwave pulse excitation at the g( perpendicular) value of Co(II) at magnetic field values of 287.0 and 345.0 mT and over a range of tau values from 227 to 1316 ns. Two common sets of (14)N features are distinguished in the ESEEM spectra. One set is assigned to the remote (N1) nitrogen in the dimethylbenzimidazole alpha-axial ligand by using two independent approaches: (a) comparison of ESEEM from cob(II)alamin with ESEEM from cob(II)inamide-ligand model compounds and (b) from the correspondence between the N1 (14)N nuclear quadrupole parameters derived from ESEEM simulations and those computed by using density functional theory. The second set is assigned to the corrin ring (14)N nuclei. The results identify the coenzyme's on-board dimethylbenzimidazole moiety as the alpha-axial ligand to cob(II)alamin in ethanolamine deaminase in the substrate radical-Co(II) biradical catalytic intermediate state. Thus, Co(II) is a pentacoordinate, alpha-axial liganded complex during turnover. We infer that dimethylbenzimidazole is also the alpha-axial ligand to the intact coenzyme in the resting enzyme. A 14% increase in the isotropic hyperfine coupling of the remote dimethylbenzimidazole (14)N nucleus in enzyme-bound versus free base-on cob(II)alamin shows an enhanced delocalization of unpaired spin density from Co(II) onto the axial ligand, which would contribute to the acceleration of the cobalt-carbon bond cleavage rate in situ.

Benzimidazoles↗
PubMed1998

Lysine-rich gamma-zeins are secreted in transgenic Arabidopsis plants.

We have previously shown that the maize (Zea mays L.) storage prolamine gamma-zein, accumulates in endoplasmic reticulum-derived protein bodies in transgenic plants of Arabidopsis thaliana (L.) ecotype R + P. The retention of gamma-zein in the endoplasmic reticulum was found to be mediated by structural features contained in the polypeptide, an N-terminal proline-rich and a C-terminal cysteine-rich domain which were necessary for the correct retention and assembly of gamma-zein within protein bodies (M.I. Geli et al., 1994, Plant Cell 6: 1911-1922). In the present work we incorporated in the gamma-zein gene lysine-rich coding sequences which were positioned after the N-terminal proline-rich domain and at five amino-acid residues from the C-terminus. The targeting of lysine-rich gamma-zeins was analyzed by expression of chimeric genes regulated by the cauliflower mosaic virus (CaMV) 35S promoter in transgenic Arabidopsis plants. The lysine-rich gamma-zeins were detected by immunoblotting and we found that these proteins were modified posttranslationally to reach their mature form. Subcellular fractionation and immunocytochemical studies demonstrated that glycosylated lysine-rich gamma-zeins were secreted to the cell wall of transgenic Arabidopsis leaf cells.

Arabidopsis↗
PubMed1998

The bifactorial endosperm box of gamma-zein gene: characterisation and function of the Pb3 and GZM cis-acting elements.

The proximal region of the gamma-zein promoter (gamma Z) has a functional bifactorial prolamin box element containing two cis-acting elements, a prolamin-box motif (Pb3) and a GCN4-like motif (GZM). By particle bombardment of maize endosperms with 5' deletions and internal deletions of gamma Z fused to the GUS gene, we have shown that a 135 bp region containing the bifactorial element is involved in the transcriptional activation of the gamma Z promoter. However, the 135 bp region was unable to activate the gamma Z promoter in the absence of a 84 bp downstream sequence. Using in vivo footprinting and gel mobility shift assays with 15 DAP endosperm nuclear extracts, we have demonstrated the presence of trans-acting factors that interact with Pb3 and GZM target sites. Base-substitution mutations within Pb3 and GZM decreased transcription activity of the gamma Z promoter suggesting a co-ordinated function between the two cis-acting elements. Two additional cis-motifs upstream of the bifactorial prolamin element have been identified: a motif with high homology to the AACA elements of rice glutelin genes and an AZM motif containing an ACGT core which binds nuclear proteins other than the Opaque 2 (O2).

Base Sequence↗
PubMed1997

Lysine-rich modified gamma-zeins accumulate in protein bodies of transiently transformed maize endosperms.

During maize seed development, endosperm cells synthesize large amounts of storage proteins, alpha-, beta-, and gamma-zeins, which accumulate within endoplasmic reticulum (ER)-derived protein bodies. The absence of lysine in all zein polypeptides results in an imbalance in the amino acid composition of maize seeds. We modified the maize gamma-zein gene through the introduction of lysine-rich (Pro-Lys)n coding sequences at different sites of the gamma-zein coding sequence. Maize endosperms were transiently transformed by biolistic bombardment with Lys-rich gamma-zein constructs under the control of the 1.7 kb gamma-zein seed-specific promoter and the cauliflower mosaic virus (CaMV) 35S promoter. When (Pro-Lys)n sequences were inserted contiguous to or in substitution of the Pro-Xaa region of the gamma-zein, high levels of protein were observed. In contrast, when (Pro-Lys)n sequences were inserted five residues from the C-terminal, the transcript was present but modified protein was not detected. These results suggest that only an appropriate positioning of Lys-rich inserts leads to the modified molecule displaying correct folding and stability. Subcellular localization analyses and immunoelectron microscopy studies on isolated protein bodies demonstrated that modified gamma-zeins accumulate within these organelles and co-localized with endogenous alpha- and gamma-zeins. The studies reported here show the feasibility of manipulating the gamma-zein gene in order to obtain stable and correctly targeted Lys-rich zeins in maize seeds.

Cloning, Molecular↗
PubMed1996

Proliferation-dependent changes in arachidonic acid mobilization from phospholipids of 3T6 fibroblasts.

When we stimulated 3T6 fibroblasts, we observed a mobilization of arachidonic acid (AA) from phospholipids. The magnitude of this response decreased as the cells became confluent and the change coincided with a decrease in the percentage of cells in growth phases (G2 + M); this was not a consequence of the time in culture or a factor in the growth medium. Preconfluent fibroblasts incubated with the calcium ionophore A23187 (1 microM), 4beta-phorbol-12-myristate acetate (PMA, 10 microM), bradykinin (10 microM) or fetal calf serum (20%) released 38.8%, 62.5%, 11.2% and 45.6% [3H]AA, respectively. Confluent cells stimulated under the same conditions released only 16.9%, 1.5%, 0.5% and 18.5% [3H]AA, respectively. This decreasing mobilization of AA was demonstrated using metabolic labelling and measurement of prostaglandin PGE2. The decrease was not due to a changing pool of AA. [3H]AA release from each phospholipid decreased with confluence. Conversion of confluent cells to the proliferative phenotype by mechanical wounding of the monolayer increased the release of [3H]AA. This effect is consistent with regulated, growth-dependent changes in the activity of phospholipase A2, a process regulated by changes in phosphorylation of the enzyme. The increased release of [3H]AA from preconfluent, actively dividing cells may have important physiological implications and may help elucidate mechanisms regulating release of AA.

Animals↗
PubMed1994

Nutritional factors and gastric cancer in Spain.

A case-control study on diet and gastric cancer, carried out in selected areas of four regions of Spain (Aragon, Castile, Catalonia, and Galicia) in 1988 and 1989, included 354 cases of histologically confirmed gastric adenocarcinoma and 354 controls matched by age, sex, and area of residence. Cases and controls were selected from 15 hospitals, representing most of the hospital facilities in the study areas. Usual diet was estimated by means of a dietary history questionnaire administered by interview. An increased risk of gastric cancer was observed for high consumption of exogenous nitrosamines (odds ratio = 2.1 for the highest quartile of consumption versus the lowest; p for linear trend = 0.007), nitrites, fat, and cholesterol. However, in a multivariate regression model, the effect of fat and cholesterol disappeared. An inverse association with the risk for gastric cancer was seen for high intake of fiber, vitamin C, folate, carotene, and nitrates. High consumption of vitamin C seemed to neutralize the increased risk related to simultaneous consumption of nitrosamines. For histologic type, the authors found no meaningful differences in the effect of most of the nutrients between intestinal and diffuse cancers. Their findings are consistent with previously reported results about the protective effect of fruit and vegetables and the increased risk associated with foods that are important sources of nitrites and preformed nitrosamines.

Adenocarcinoma↗
PubMed1994

Role of structural domains for maize gamma-zein retention in Xenopus oocytes.

In order to examine the role of cysteine (Cys)-rich domains in the accumulation of maize (Zea mays L.) gamma-zein within the endoplasmic-reticulum-derived protein bodies, we studied the localization of gamma-zein and of two truncated forms of gamma-zein in Xenopus laevis oocytes. The two derivatives were constructed from a DNA encoding the gamma-zein: one by deletion of the Pro-X linker region (21 amino acids) and the other by deletion of the Cys-rich domain (94 amino acids). In-vitro-synthesized transcripts were injected into oocytes and the distribution of the translation products was then analyzed. The entire gamma-zein and both truncated forms of the gamma-zein had accumulated efficiently in microsomes and no traces of secretion were observed. We suggest that neither C-terminal Cys-rich nor Pro-X domains are essential for gamma-zein retention in oocyte vesicles. Therefore, structural features derived from disulphide bonds are not necessary for gamma-zein targeting on the endoplasmic reticulum.

Amino Acid Sequence↗
PubMed1994

The maize abscisic acid-responsive protein Rab17 is located in the nucleus and interacts with nuclear localization signals.

The maize abscisic acid (ABA)-responsive rab17 mRNA and Rab17 protein distribution in maize embryo tissues was investigated by in situ hybridization and immunocytochemistry. rab17 mRNA and Rab17 protein were found in all cells of embryo tissues. Synthesis of rab17 mRNA occurred initially in the embryo axis. As maturation progressed, rab17 mRNA was detectable in the scutellum and accumulated in axis cells and provascular tissues. However, the response to exogenous ABA differed in various embryo cell types. The Rab17 protein was located in the nucleus and in the cytoplasm, and qualitative differences in the phosphorylation states of the protein were found between the two subcellular compartments. Based on the similar domain arrangements of Rab17 and a nuclear localization signal (NLS) binding phosphoprotein, Nopp140, interaction of Rab17 with NLS peptides was studied. We found specific binding of Rab17 to the wild-type NLS of the SV40 T antigen but not to an import incompetent mutant peptide. Moreover, binding of the NLS peptide to Rab17 was found to be dependent upon phosphorylation. These results suggest that Rab17 may play a role in nuclear protein transport.

Abscisic Acid↗
PubMed1990

Dietary habits in Spain: an approximation.

The dietary pattern of a population sample of males selected as a control group for a case-control study on bladder cancer carried out in four different regions of Spain is presented. Out of 807 population controls initially selected, 530 were interviewed, 465 males and 65 females. The method of selection of the study subjects and the diet assessment method are described. Our results confirm the Mediterranean pattern of the Spanish diet, with an important consumption of fresh fish, fruits and vegetables, and the use of vegetable oils, specially olive oil, for cooking and seasoning, accompanied with a high polyunsaturated/saturated ratio (0.7). The consumption of butter, cheese and other dairy products, on the other hand, is very low. Estimated total caloric intake is relatively low if compared with international figures, although questionnaire base assessment may seriously underestimate caloric intake, as it is the absolute amount of intake of lipids and carbohydrates. In relative terms, however, lipids provide the highest percentage of calories.

Adult↗
PubMed1990

Gene sequence, developmental expression, and protein phosphorylation of RAB-17 in maize.

The ABA-induced MA12 cDNA from maize, which encodes a set of highly phosphorylated embryo proteins, was used to isolate the corresponding genomic clone. This gene, called RAB-17 (responsive to ABA), encodes a basic, glycine-rich protein (mol. wt. 17,164) containing a cluster of 8 serine residues, seven of them contiguous. It is a homologue of the rice RAB-21 gene (Mundy J, Chua NH, EMBO J 7; 2279-2286, 1988). Phosphoamino acid analysis of the isolated protein indicates that only the serine residues are phosphorylated and a putative casein-type kinase phosphorylatable sequence was identified in the protein. The pattern of expression and in vivo phosphorylation of the RAB-17 protein was studied during maize embryo germination and in calli of both meristematic or embryonic origin. ABA treatment induced the synthesis of RAB-17 mRNA and protein in calli, however, the RAB-17 proteins were found to be highly phosphorylated only in embryos.

Abscisic Acid↗
PubMed1990

Hospital versus neighbourhood controls in the assessment of dietary risk factors.

The selection of the best control group is a major concern in the design of any case-control study, because of its enormous implications on both interval validity and cost. We compare the dietary habits of hospital and neighbourhood control groups which had both been used in a case-control study on bladder cancer. The analysis is based on 485 matched sets. No differences were observed between the two groups in terms of nutrient consumption nor in consumption of specific foods or food groups. Alcohol consumption represents an exception. This may be attributed to the use of incorrect exclusion criteria given that alcohol consumption was not one of the major determinants of the original study. We conclude that, provided correct exclusion criteria are used, hospital controls may be a suitable as neighbourhood controls in the assessment of dietary risk factors in case-control studies in Spain.

Alcohol Drinking↗
PubMed1988

Signal recognition-like particles are present in maize.

We show that maize storage protein translocation across microsomal membranes is mediated by signal recognition particles (SRPs) similar to those described in animal systems (Dobberstein, B. (1978) Hoppe-Seyler's Z. Physiol. Chem. 252, 955-962; Walter, P., and Blobel, G. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 7112-7116). We have prepared a high salt extract from endosperm cell homogenates, from which a ribosome-free fraction was obtained. This fraction is enriched in an SRP-like factor which apparently corresponds to a ribonucleoprotein particle that sediments at about 12 S. The RNA moiety of this 12 S particle is complex, showing a three-band electrophoretic pattern and sedimenting at about 8 S. The fraction restores translocation competence of salt-washed maize microsomes as tested by using a pre-zein message. In contrast to canine SRPs, the maize SRP-like component does not cause a translation arrest of maize storage proteins (zein) in a wheat germ cell-free system.

Animals↗
PubMed1988

The use of two-dimensional gel electrophoresis in the analysis of organ-specific maize proteins.

Two-dimensional gel electrophoresis with non-equilibrium pH gradient electrophoresis in the first dimension and sodium dodecyl sulfate-polyacrylamide gels in the second dimension has been used for the analysis of organ-specific proteins in maize. The method has been used to study the whole protein pattern of developing organs and adult leaves as well as protein patterns of in vitro translation. Examples of two-dimensional immunoblotting and in vitro translation of endosperm-specific proteins are also shown. Two-dimensional gel electrophoresis appears as an essential analytical step in the identification of organ-specific proteins and for the detection of the protein products related to organ-specific genes identified by other means.

Chloroplasts↗