ana rivas

Helicobacter pylori ATCC43504 responds chemotactically to aspartic acid and serine, but not to arginine, nor to sodium bicarbonate. In contrast, H. pylori ATCC700392 (strain 26695) shows chemotaxis to all four attractants. Open reading frame HP0099 from H. pylori 26695 is predicted to encode one of three methyl-accepting chemotaxis receptor proteins (MCPs). When Escherichia coli is transformed with a plasmid carrying HP0099 from strain 26695, the recombinants acquire chemotaxis to arginine, bicarbonate, and urea. In H. pylori 43504, the HP0099 gene is interrupted with a mini-IS605 insertion, which accounts for its inability to recognize arginine and bicarbonate as attractants. Together, these results argue that the H. pylori HP0099 gene encodes an MCP for arginine and bicarbonate.

To determine the existence of an acid stress response in Helicobacter pylori the global changes in the proteins synthesized by the bacterium when subjected to an acid stress were studied. H. pylori ATCC43504 previously adapted to pH 7 did not show an acid stress response as detected by the two-dimensional electrophoretic pattern of 35S-labeled proteins when incubated at pH 3. This was probably due to the neutralization of the external medium by the action of urease. However, H. pylori DW504UreI-negative, a mutant strain unable to transport urea into the cell, showed a large number of proteins changed, as is typical in an acid stress response. Some of these proteins were identified by N-terminal sequencing.

We hypothesized that adherence to the Mediterranean diet measured as a Mediterranean diet score (MDS) has a beneficial effect on bone mineral density (BMD). For the purposes of this study, a sample of healthy women from Southern Spain was chosen. Subjects were grouped into two major groups: a first group consisted of women of reproductive age (premenopausal, pre-M) and a second group consisted of postmenopausal women (pos-M). The consumption of vegetables and fruit was found to be significantly related to BMD in both groups of subjects studied. In the pre-M group, the lipid ratio was positively associated with BMD and in pos-M women nuts intake was also associated with BMD. After implementing the analysis of covariance analysis, significant linear trends between the MDS and BMD were observed in all subjects studied. Our results indicate that a varied diet based on Mediterranean diet patterns may be beneficial in the prevention of osteoporosis.

We deal with the problem of observability of a given subset V1 of flows in terms of another subset V2, no matter which type of flows [link, origin-destination (OD), route, node, plate scanned, etc.] they contain or whether they are mixed types. Two problems are stated: The first consists of determining which subsets of flows in V1 can be calculated in terms of the observed flows V2. The second consists of determining which subset of flows V2 needs to be observed to calculate a given subset V1. A theorem providing necessary and sufficient conditions for observability is provided and used in the proposed methods to solve the two problems. Two theorems, one lemma, and one corollary provide the bases for optimizing the numerical procedures to solve these problems. Some examples of applications are used to illustrate the proposed methods.

Abstract—This paper discusses the problem of optimizing the use of scanning resources for route flow estimation in traffic net-works. Three problems are considered: 1) Minimize the number of cameras to be used for estimating a given subset of route flows; 2) identify the subsets ...

The widespread presence of organochlorine (OC) pesticides in human samples may be explained by the environmental exposure of the population. Foods are considered a constant source of exposure, despite compliance with maximum permitted residue levels. This study aimed to examine the relationship between nutritional habits of women in Southeast Spain and their serum concentrations of OCs. A semi-quantitative questionnaire was used to estimate the frequency of consumption of foods by two age groups of women, pre-menopausal (Pre-M) and post-menopausal (Post-M), and their serum pesticide levels were measured by gas chromatography (GC) with electron capture detector and confirmed by GC and mass spectrometry. The Pre-M group showed significantly higher serum concentrations of all OCs studied with the exception of DDE. The groups significantly differed in consumption of all food groups with the exception of fruit. In the Pre-M group, the mean serum p,p-DDT concentration was significantly associated with milk/yoghurt (p<0.045) and red meat (p<0.023), serum o,p-DDT with red meat (p<0.049), serum aldrin with eggs (p<0.038) and poultry (p<0.024), and serum DDE with eggs (p<0.025). In the Post-M group, serum lindane was associated with fresh and cured cheese (p<0.001), red meat (p<0.001) and white and oily fish (p<0.001), and both serum DDE and dieldrin were associated with fresh cheese, cured cheese, red meat, and white and oily fish (p<0.001). These results confirm foods as a source of human exposure to persistent organic molecules. Consideration should be given to the reduction of permitted residue levels to minimize this threat to human and animal health.

The aim of this study was to measure selected metal concentrations in Trachurus trachurus, Trachurus picturatus, and Trachurus mediterraneus, which are widely consumed in Spain. Principal component analysis suggested that the variable Cr was the main responsible variable for the identification of T. trachurus, the variables As and Sn for T. mediterraneus, and the rest of variables for T. picturatus. This well-defined discrimination between fish species provided by mineral element allows us to distinguish them on the basis of their metal content. Based on the samples collected, and recognizing the inferential limitation of the sample size of this study, the metal concentrations found are below the proposed limit values for human consumption. However, it should be taken into consideration that there are other dietary sources of these metals. In conclusion, metal contents in the fish species analyzed are acceptable for human consumption from a nutritional and toxicity point of view.

Numerous studies have addressed the nutritional needs of pregnant women. The nutritional status of the woman before and during gestation affects the growth of the fetus and the course of the pregnancy and influences the risk of obesity for mother and infant. The aim of this study was to propose a diet quality index for pregnancy based on a Mediterranean-type diet (MDS-P), evaluating the diet of a group of pregnant women by applying the Mediterranean Diet Score (MDS) and evaluating their intake of micronutrients required in optimal amounts during pregnancy, such as Fe, folic acid and Ca. The data used to construct this index (MDS-P) were gathered by means of a FFQ specifically designed for pregnant women. The mean MDS of this group, was 4.31 (sd 1.32), considered to represent satisfactory compliance with the Mediterranean diet (range 0-8). The mean MDS-P (range 0-11), which also takes account of dietary intake or supplements of folic acid, Fe and Ca was 7.53 (sd 1.44), indicating a compliance of around 70 %. The present study findings suggest that the MDS-P, which evaluates the adequacy of folic acid, Fe and Ca as well as compliance with the Mediterranean diet, may represent a valid tool for the specific assessment of the diet of pregnant women living in countries in the Mediterranean area. Further studies are required to complete the validation process.

The Mediterranean diet is considered one of the healthiest dietary models. Recent changes in the actual Mediterranean diet include a reduction in energy intake and a higher consumption of foods with low nutrient density (e.g. soft drinks, candy, sweets, etc.). In Spain, in association with cultural and lifestyle changes, there has been a reduction in the intake of antioxidants and vitamins, an increase in the proportion of SFA and a decrease in the consumption of fibre, among other changes. Children and adolescents may be the age groups with the most deteriorated Mediterranean diet. The current paper presents the results of applying the Mediterranean Diet Quality Index for children and adolescents (KIDMED) to a large sample of Spanish schoolchildren. Data from questionnaires were used to calculate the KIDMED index. Granada, Southern Spain. Schoolchildren (n 3190) aged 8-16 years. Among the 8-10-year-olds, the KIDMED index classification was 'good' in 48.6% of the population, 'average' in 49.5% and 'poor' in 1.6%. Among the 10-16-year-olds, the KIDMED index classification was good in 46.9% of the population, average in 51.1% and poor in 2.0%. The nutritional behaviour of the present population of schoolchildren is similar to that found in the earlier KIDMED study.

Bisphenols constitute a family of compounds, which includes many substances that have as a common chemical structure two phenolic rings joined together through a bridging carbon. In the present study, we aimed to determine whether several events triggered by 17 β-estradiol (E2) in MCF-7 breast cancer cells were also observed in response to various bisphenol-A (BPA) analogues. We studied the expression of estrogen controlled genes by measuring the induction of pS2 (mRNA and protein) and progesterone receptor (PgR) as well as the expression of a luciferase reporter gene transfected into MVLN cells. These data were compared to the cell proliferation potency and effectiveness as the latest expression of estrogen controlled functions. Bisphenols showed an agonistic effect in all our assays, suggesting that these compounds may act through all the response pathways triggered by the natural hormone. We found differences between the assays in the potency of bisphenols, defined as the minimum concentration required to produce a maximal effect. In the cell proliferation assay, all tested compounds needed a lower concentration than in the other assays to give maximal response. Our results suggest that the polarity and nature of the substituent in the central carbon determines the estrogenic potency. Presence of two propyl chains at the central carbon appears to confer the greatest potency in both gene and protein expression assays.

It has been hypothesized that endocrine disruptors and especially synthetic estrogenic environmental contaminants (xenoestrogens) are etiologic factors in the global decrease of sperm counts and other problems of the male reproductive tract, including cryptorchidism, hypospadias, and testicular cancer. This possibility has prompted research into the current and historical incidence of these diseases. The largest area of intensive greenhouse agriculture in Europe is near the Mediterranean coast of Southern Spain, where this activity has greatly expanded since the 1960s. We determined and compared levels of 14 organochlorine pesticides in the blood of 220 young males in Southern Spain. Aldrin, dieldrin, endrin, lindane, methoxychlor, endosulfans, and DDT and its metabolites were identified. Detectable concentrations of p,p′-DDE were found in 96% of serum samples. Among the remaining DDTs, o,p′-DDD was the most prevalent, detected in 65% of serum samples. Detectable concentrations of endosulfan I or II or their metabolites endosulfan-diol, or -sulfate were found in all samples; endosulfan-diol was the most frequently detected metabolite (92%) followed by sulfate. Results indicate that men of reproductive age in Southern Spain have been and are exposed to organochlorine pesticides. Because many of these chemicals have estrogenic and anti-androgenic activity, further research is warranted to interpret the male reproductive health consequences of this exposure.

Organochlorine pesticides are lipophilic compounds that persist in the environment. Because of their lipid solubility and resistance to metabolism, some of these chemicals accumulate in human tissues. The largest area of intensive greenhouse agriculture in Europe is near the Mediterranean coast of Southern Spain, where this type of farming has greatly expanded since the 1960s. We determined and compared the levels of 15 organochlorine pesticides in the adipose tissue and blood of 200 women living in Southern Spain. Aldrin, dieldrin, endrin, lindane, methoxychlor, endosulfans, and DDT and its metabolites were identified. Detectable concentrations of p,p′-DDE were found in 100% of adipose tissue and serum samples. Among the remaining DDTs, p,p′-DDT was the most common, being detected in 39% of adipose tissue and 76.5% of serum samples, followed by endosulfans I and II, which also were found in both adipose tissue and serum samples but at lower concentrations. Endosulfans were followed in frequency by lindane, aldrin, and dieldrin. Endrin and methoxychlor were present at a much lower frequency compared to those of the other organochlorines. Serum concentrations of p,p′-DDE o,p′-DDD, and endosulfan -I, -sulfate, -lactone, and -diol were significantly correlated with their adipose tissue concentrations. No significant relationships were found between the serum and adipose tissue concentrations of the remaining nine compounds determined, raising doubts about the equivalent use of fat/serum samples for the exposure assessment of some pesticides in epidemiological studies. The results suggested that women of reproductive age in Southern Spain have been and are currently exposed to organochlorine pesticides. Because many of these chemicals can mobilize during pregnancy and lactation, further research is warranted to interpret the health consequences for the children of such exposure.

Despite the prohibition of most persistent organochlorine (OC) pesticides in Spain, their presence has been widely documented in adult human tissues. However, scarce information is available on the exposure of children. The aim of the present study was to investigate the presence of 16 OC pesticide residues in 52 fat samples collected from boys with a mean age of 7 yr (0–15 yr) living in Southern Spain and to assess the association between OC pesticide levels and child characteristics. No pesticide was found in more than 50% of samples, except for p,p′-DDE (79% of samples; median, 710 ng/g lipid). After this compound, the most frequent pesticides were o,p′-DDT (17%; median, 330 ng/g lipid) and o,p′-DDD (15%; median, 1510 ng/g lipid). No statistically significant association was found between p,p′-DDE or ∑DDTs and the birth year, birth weight, gestational age, infant feeding history or the age, weight, height or Quetelet Index at the time of sampling. The lack of correlation between the presence of the main metabolite p,p′-DDE and that of the parent compounds, o,p′-DDT and p,p′-DDT, suggests that children were exposed mainly to the metabolite rather than to the commercial pesticide, which was banned 30 yr ago. In contrast, among currently used OCs, endosulfan was positively correlated with the presence of its metabolites, suggesting exposure to the commercial products. Further research is warranted to investigate the health consequence in children resulting from exposure to chemicals suspected of endocrine-disrupting effects.

Test systems to screen for estrogenicity and appropriate biomarkers of human exposure are required for epidemiological studies of endocrine disruption. We addressed these issues by developing and standardising a method to assess the total estrogenic xenobiotic burden in human adipose tissue. In this study, which is the continuation of a previous work, we have improved the protocol for extensive fractionation of a higher number of tissue samples in order to investigate bioaccumulated xenoestrogens that are candidates for estrogenicity and to assess their combined estrogenic effect. This was achieved by extensive HPLC separation of xenoestrogens from endogenous hormones followed by testing of individual fractions in the E-Screen test for estrogenicity. Organochlorine pesticides, PCBs and halogenated bisphenols and alkylphenols were collected in the most lipophilic fractions, followed by progestins, androgens and estradiol esters, and then by steroidal estrogens; phyto- and myco-estrogens were collected around the end of the run. These results were confirmed by exhaustive chemical analysis. In 458 human adipose tissue samples, the total effective xenoestrogen burden was positive in 75% of samples in the pooled fraction that contained organohalogenated xenoestrogens (mean 515.3 pM Eeq/g lipid; range 0–14.5 nM) and in 82% of samples in the pooled fraction where natural estrogens eluted (mean 696.6 pM Eeq/g lipid; range 0–12.9 nM). Organochlorine pesticides emerged as candidate chemicals for the estrogenicity of the first pooled fraction, because DDT and derivatives were present in 98.3% of the samples. However, no correlation was found between the concentration of any single chemical and the estrogenicity determined in the bioassay. There may be several reasons for this lack of concordance: (i) the estrogenic effects depicted in the E-Screen bioassay are a consequence of the combined effect of several organohalogens or (ii) the proliferative effect is due to other chemicals not measured. Because additive, synergistic or antagonistic mechanisms may account for the final effect observed in the pooled fractions, the approach proposed in this work is more appropriate for exposure assessment in epidemiological studies than the determination of individual chemicals in human samples.

Foetal exposure of male rats to di(n-butyl) phthalate (DBP) induces testicular changes similar to testicular dysgenesis syndrome in humans, including the formation of focal ‘dysgenetic areas’ within post-natal testes, surrounded by otherwise normal tubules exhibiting complete spermatogenesis. We hypothesize that these dysgenetic areas form when Sertoli (and other) cells are ‘trapped’ during the abnormal formation of large Leydig cell (LC) clusters in foetal life and by post-natal day (d) 4 these groups of intermingled cells attempt to form seminiferous tubules. It is likely that the malformed tubules resulting correspond to the dysgenetic areas evident in later life. This also provides a plausible explanation for the occurrence of LCs within seminiferous cords/tubules in or bordering the dysgenetic areas. In our previous studies intratubular LCs (ITLCs) were identified by immunostaining for 3β-hydroxysteroid dehydrogenase (3β-HSD), the definitive LC cytoplasmic marker. However, the possibility remained that the ‘presumptive’ ITLCs were in fact Sertoli cells that had aberrantly gained the ability to express 3β-HSD. Therefore, the aim of the present study was to fully characterize the ITLCs induced by in utero DBP exposure in d25 rats using a number of LC- (3β-HSD, P450 side-chain cleavage enzyme, insulin-like factor 3, oestrogen receptor alpha) and Sertoli cell- (vimentin, Wilm's tumour-1) specific markers. Our results show that ITLCs express all four LC-specific markers but do not express either of the Sertoli cell markers. It is therefore concluded that the ITLCs are bona fide LCs that are abnormally located within the seminiferous tubules of DBP-exposed rats in post-natal life.