Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46% of IM, 50% of GU, and 79% of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 �� 2.605 and 2.730 �� 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 �� 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38% of IM, 39% of GU, and 55% of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

��tude structure-fonction des fructose-1,6-bisphosphate aldolases m��tallo-d��pendantes : m��canisme catalytique et d��veloppement d���antimicrobiens

Les fructose-1,6-bisphosphate aldolases (FBPA) sont des enzymes glycolytiques (EC 4.1.2.13) qui catalysent la transformation r��versible du fructose-1,6-bisphosphate (FBP) en deux trioses-phosphates, le glyc��rald��hyde-3-phosphate (G3P) et le dihydroxyac��tone phosphate (DHAP). Il existe deux classes de FBPA qui diff��rent au niveau de leur m��canisme catalytique. Les classes I passent par la formation d���un interm��diaire covalent de type iminium alors que les classes II, m��tallod��pendantes, utilisent g��n��ralement un zinc catalytique. Contrairement au m��canisme des classes I qui a ��t�� tr��s ��tudi��, de nombreuses interrogations subsistent au sujet de celui des classes II. Nous avons donc entrepris une analyse d��taill��e de leur m��canisme r��actionnel en nous basant principalement sur la r��solution de structures cristallographiques. De nombreux complexes �� haute r��solution furent obtenus et ont permis de d��tailler le r��le de plusieurs r��sidus du site actif de l���enzyme. Nous avons ainsi corrig�� l���identification du r��sidu responsable de l���abstraction du proton de l���O4 du FBP, une ��tape cruciale du m��canisme. Ce r��le, faussement attribu�� �� l���Asp82 (chez Helicobacter pylori), est en fait rempli par l���His180, un des r��sidus coordonant le zinc. L���Asp82 n���en demeure pas moins essentiel car il oriente, active et stabilise les substrats. Enfin, notre ��tude met en ��vidence le caract��re dynamique de notre enzyme dont la catalyse n��cessite la relocalisation du zinc et de nombreux r��sidus. La dynamique de la prot��ine ne permet pas d�����tudier tous les aspects du m��canisme uniquement par l���approche cristallographique. En particulier, le r��sidu effectuant le transfert st��r��osp��cifique du proton pro(S) sur le carbone 3 (C3) du DHAP est situ�� sur une boucle qui n���est visible dans aucune de nos structures. Nous avons donc d��velopp�� un protocole de dynamique mol��culaire afin d�����tudier sa dynamique. Valid�� par l�����tude d���inhibiteurs de la classe I, l���application de notre protocole aux FBPA de classe II a confirm�� l���identification du r��sidu responsable de cette abstraction chez Escherichia coli (Glu182) mais pointe vers un r��sidu diff��rent chez H. pylori (Glu149 au lieu de Glu142). Nos validations exp��rimentales confirment ces observations et seront consolid��es dans le futur. Les FBPA de classe II sont absentes du prot��ome humain mais sont retrouv��es chez de nombreux pathog��nes, pouvant m��me s'y r��v��ler essentielles. Elles apparaissent donc comme ��tant une cible id��ale pour le d��veloppement de nouveaux agents anti-microbiens. L���obtention de nouveaux analogues des substrats pour ces enzymes a donc un double int��r��t, obtenir de nouveaux outils d�����tude du m��canisme mais aussi d��velopper des mol��cules �� vis��e pharmacologique. En collaboration avec un groupe de chimistes, nous avons optimis�� le seul inhibiteur connu des FBPA de classe II. Les compos��s obtenus, �� la fois plus sp��cifiques et plus puissants, permettent d���envisager une utilisation pharmacologique. En somme, c���est par l���utilisation de techniques compl��mentaires que de nouveaux d��tails mol��culaires de la catalyse des FBPA de classe II ont pu ��tre ��tudi��s. Ces techniques permettront d���approfondir la compr��hension fine du m��canisme catalytique de l���enzyme et offrent aussi de nouvelles perspectives th��rapeutiques.

Le syst��me de recombinaison site-sp��cifique dif/Xer de Campylobacter jejuni

Chez les bact��ries �� chromosome circulaire, la r��plication peut engendrer des dim��res que le syst��me de recombinaison site-sp��cifique dif/Xer r��sout en monom��res afin que la s��gr��gation des chromosomes fils et la division cellulaire se fassent normalement. Ses composants sont une ou deux tyrosines recombinases de type Xer qui agissent �� un site de recombinaison sp��cifique, dif, avec l���aide de la translocase FtsK qui mobilise l���ADN au septum avant la recombinaison. Ce syst��me a ��t�� d���abord identifi�� et largement caract��ris�� chez Escherichia coli mais il a ��galement ��t�� caract��ris�� chez de nombreuses bact��ries �� Gram n��gatif et positif avec des variantes telles que les syst��mes �� une seule recombinase comme difSL/XerS chez Streptococcus sp et Lactococcus sp. Des ��tudes bio-informatiques ont sugg��r�� l���existence d���autres syst��mes �� une seule recombinase chez un sous-groupe d�����-prot��obact��ries pathog��nes, dont Campylobacter jejuni et Helicobacter pylori. Les acteurs de ce nouveau syst��me sont XerH et difH. Dans ce m��moire, les premi��res recherches in vitro sur ce syst��me sont pr��sent��es. La caract��risation de la recombinase XerH de C. jejuni a ��t�� entam��e �� l���aide du s��quen��age de son g��ne et de tests de liaison et de clivage de l���ADN. Ces ��tudes ont montr�� que XerH pouvait se lier au site difSL de S. suis de mani��re non-coop��rative : que XerH peut se lier �� des demi-sites de difSL mais qu���elle ne pouvait, dans les conditions de l�����tude effectuer de clivage sur difSL. Des recherches in silico ont aussi permis de faire des pr��dictions sur FtsK de C. jejuni.

C��ncer g��strico en Colombia entre 2000 y 2009

Introducci��n: De todos los casos de c��ncer en el mundo el 80% se presentan en pa��ses en v��a de desarrollo siendo el c��ncer de est��mago o c��ncer g��strico la segunda causa de muerte por c��ncer en el mundo con aproximadamente 700.000 muertes cada a��o. En Colombia, el c��ncer g��strico es la primera causa de muerte por tumores malignos en ambos sexos, a��n cuando no es la primera neoplasia en frecuencia. Metodolog��a: Estudio observacional descriptivo, de registros de defunci��n del DANE, Colombia 2000 a 2009. Se analizaron tasas anuales crudas y por grupos de edad, g��nero, procedencia geogr��fica, estado civil, nivel educativo y ��rea de residencia habitual estableciendo diferencias estad��sticas entre las variables y sus categor��as. Resultados: En el per��odo estudiado se registraron 43759 defunciones por c��ncer g��strico, con mayor frecuencia en hombres 1,5:1. Las tasas de mortalidad por c��ncer g��strico ajustadas por grupos et��reos aumentan despu��s de la quinta d��cada de la vida. Se encontraron diferencias estad��sticamente significativas en todos los a��os estudiados y el departamento de residencia habitual del fallecido presentando Cauca (18,11- 19) y Boyac�� (14,54-1742) las tasas m��s altas por 100.000 habitantes. Las tasas m��s altas se concentran en la zona de la Cordillera de los Andes, al estandarizar por grupos et��reos el Cauca tiene una tasa de 114,98 casos por 100.000 habitantes. Conclusi��n: El c��ncer g��strico es la neoplasia que causa m��s muertes en Colombia por lo cual es necesario dise��ar e implementar programas de detecci��n precoz que vayan dirigidos al control de la mortalidad.

Dispepsia: un real desaf��o diagn��stico

La presente es una revisi��n no sistem��tica de literatura con la siguiente estrategia de b��squeda: (((((���Dyspepsia��� [Mesh] OR ���Peptic Ulcer��� [Mesh]) OR ���Helicobacter pylori��� [Mesh]) AND (���Diagnosis���[Mesh] OR (���Therapeutics��� [Mesh OR ���therapy ���[Subheading])) OR ���Epidemiology��� [Mesh]. La indagaci��n contempl�� el periodo comprendido entre los a��os 1966 y 2007. La estrategia de b��squeda fue adaptada a cada una de las bases de datos consultadas: MEDLINE, COCHRANE, LILACS y SCIELO. Se encontraron, por t��tulo y abstract, 689 art��culos, a criterio de los autores, de los cuales fueron seleccionados 138 para esta revisi��n. No se obtuvieron 6 art��culos por no tener acceso a los correspondientes journals. El prop��sito de esta revisi��n es dar a conocer y aclarar algunos puntos sobre el diagn��stico y tratamiento de la dispepsia.

New scientific paradigms for probiotics and prebiotics

The inaugural meeting of the International Scientific Association for Probiotics and Prebiotics (ISAPP) was held May 3 to May 5 2002 in London, Ontario, Canada. A group of 63 academic and industrial scientists from around the world convened to discuss current issues in the science of probiotics and prebiotics. ISAPP is a non-profit organization comprised of international scientists whose intent is to strongly support and improve the levels of scientific integrity and due diligence associated with the study, use, and application of probiotics and prebiotics. In addition, ISAPP values its role in facilitating communication with the public and healthcare providers and among scientists in related fields on all topics pertinent to probiotics and prebiotics. It is anticipated that such efforts will lead to development of approaches and products that are optimally designed for the improvement of human and animal health and well being. This article is a summary of the discussions, conclusions, and recommendations made by 8 working groups convened during the first ISAPP workshop focusing on the topics of: definitions, intestinal flora, extra-intestinal sites, immune function, intestinal disease, cancer, genetics and genomics, and second generation prebiotics. Humans have evolved in symbiosis with an estimated 1014 resident microorganisms. However, as medicine has widely defined and explored the perpetrators of disease, including those of microbial origin, it has paid relatively little attention to the microbial cells that constitute the most abundant life forms associated with our body. Microbial metabolism in humans and animals constitutes an intense biochemical activity in the body, with profound repercussions for health and disease. As understanding of the human genome constantly expands, an important opportunity will arise to better determine the relationship between microbial populations within the body and host factors (including gender, genetic background, and nutrition) and the concomitant implications for health and improved quality of life. Combined human and microbial genetic studies will determine how such interactions can affect human health and longevity, which communication systems are used, and how they can be influenced to benefit the host. Probiotics are defined as live microorganisms which, when administered in adequate amounts confer a health benefit on the host.1 The probiotic concept dates back over 100 years, but only in recent times have the scientific knowledge and tools become available to properly evaluate their effects on normal health and well being, and their potential in preventing and treating disease. A similar situation exists for prebiotics, defined by this group as non-digestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favorable growth or activity of a limited number of indigenous bacteria. Prebiotics function complementary to, and possibly synergistically with, probiotics. Numerous studies are providing insights into the growth and metabolic influence of these microbial nutrients on health. Today, the science behind the function of probiotics and prebiotics still requires more stringent deciphering both scientifically and mechanistically. The explosion of publications and interest in probiotics and prebiotics has resulted in a body of collective research that points toward great promise. However, this research is spread among such a diversity of organisms, delivery vehicles (foods, pills, and supplements), and potential health targets such that general conclusions cannot easily be made. Nevertheless, this situation is rapidly changing on a number of important fronts. With progress over the past decade on the genetics of lactic acid bacteria and the recent, 2,3 and pending, 4 release of complete genome sequences for major probiotic species, the field is now armed with detailed information and sophisticated microbiological and bioinformatic tools. Similarly, advances in biotechnology could yield new probiotics and prebiotics designed for enhanced or expanded functionality. The incorporation of genetic tools within a multidisciplinary scientific platform is expected to reveal the contributions of commensals, probiotics, and prebiotics to general health and well being and explicitly identify the mechanisms and corresponding host responses that provide the basis for their positive roles and associated claims. In terms of human suffering, the need for effective new approaches to prevent and treat disease is paramount. The need exists not only to alleviate the significant mortality and morbidity caused by intestinal diseases worldwide (especially diarrheal diseases in children), but also for infections at non-intestinal sites. This is especially worthy of pursuit in developing nations where mortality is too often the outcome of food and water borne infection. Inasmuch as probiotics and prebiotics are able to influence the populations or activities of commensal microflora, there is evidence that they can also play a role in mitigating some diseases. 5,6 Preliminary support that probiotics and prebiotics may be useful as intervention in conditions including inflammatory bowel disease, irritable bowel syndrome, allergy, cancer (especially colorectal cancer of which 75% are associated with diet), vaginal and urinary tract infections in women, kidney stone disease, mineral absorption, and infections caused by Helicobacter pylori is emerging. Some metabolites of microbes in the gut may also impact systemic conditions ranging from coronary heart disease to cognitive function, suggesting the possibility that exogenously applied microbes in the form of probiotics, or alteration of gut microecology with prebiotics, may be useful interventions even in these apparently disparate conditions. Beyond these direct intervention targets, probiotic cultures can also serve in expanded roles as live vehicles to deliver biologic agents (vaccines, enzymes, and proteins) to targeted locations within the body. The economic impact of these disease conditions in terms of diagnosis, treatment, doctor and hospital visits, and time off work exceeds several hundred billion dollars. The quality of life impact is also of major concern. Probiotics and prebiotics offer plausible opportunities to reduce the morbidity associated with these conditions. The following addresses issues that emerged from 8 workshops (Definitions, Intestinal Flora, Extra-Intestinal Sites, Immune Function, Intestinal Disease, Cancer, Genomics, and Second Generation Prebiotics), reflecting the current scientific state of probiotics and prebiotics. This is not a comprehensive review, however the study emphasizes pivotal knowledge gaps, and recommendations are made as to the underlying scientific and multidisciplinary studies that will be required to advance our understanding of the roles and impact of prebiotics, probiotics, and the commensal microflora upon health and disease management.

Health benefits of probiotics: are mixtures more effective than single strains?

PURPOSE: Most studies on probiotics utilise single strains, sometimes incorporated into yoghurts. There are fewer studies on efficacy of mixtures of probiotic strains. This review examines the evidence that (a) probiotic mixtures are beneficial for a range of health-related outcomes and (b) mixtures are more or less effective than their component strains administered separately. RESULTS: Mixtures of probiotics had beneficial effects on the end points including irritable bowel syndrome and gut function, diarrhoea, atopic disease, immune function and respiratory tract infections, gut microbiota modulation, inflammatory bowel disease and treatment of Helicobacter pylori infection. However, only 16 studies compared the effect of a mixture with that of its component strains separately, although in 12 cases (75%), the mixture was more effective. CONCLUSION: Probiotic mixtures appear to be effective against a wide range of end points. Based on a limited number of studies, multi-strain probiotics appear to show greater efficacy than single strains, including strains that are components of the mixtures themselves. However, whether this is due to synergistic interactions between strains or a consequence of the higher probiotic dose used in some studies is at present unclear.

Detection of urease in the cell wall and membranes from leaf tissues of bromeliad species

Urea is an important nitrogen source for some bromeliad species, and in nature it is derived from the excretion of amphibians, which visit or live inside the tank water. Its assimilation is dependent on the hydrolysis by urease (EC: 3.5.1.5), and although this enzyme has been extensively studied to date, little information is available about its cellular location. In higher plants, this enzyme is considered to be present in the cytoplasm. However, there is evidence that urease is secreted by the bromeliad Vriesea gigantea, implying that this enzyme is at least temporarily located in the plasmatic membrane and cell wall. In this article, urease activity was measured in different cell fractions using leaf tissues of two bromeliad species: the tank bromeliad V. gigantea and the terrestrial bromeliad Ananas comosus (L.) Merr. In both species, urease was present in the cell wall and membrane fractions, besides the cytoplasm. Moreover, a considerable difference was observed between the species: while V. gigantea had 40% of the urease activity detected in the membranes and cell wall fractions, less than 20% were found in the same fractions in A. comosus. The high proportion of urease found in cell wall and membranes in V. gigantea was also investigated by cytochemical detection and immunoreaction assay. Both approaches confirmed the enzymatic assay. We suggest this physiological characteristic allows tank bromeliads to survive in a nitrogen-limited environment, utilizing urea rapidly and efficiently and competing successfully for this nitrogen source against microorganisms that live in the tank water.

The iron stimulon of Xylella fastidiosa includes genes for type IV pilus and colicin V-like bacteriocins

Xylella fastidiosa is the etiologic agent of a wide range of plant diseases, including citrus variegated chlorosis (CVC), a major threat to citrus industry. The genomes of several strains of this phytopathogen were completely sequenced, enabling large-scale functional studies. DNA microarrays representing 2,608 (91.6%) coding sequences (CDS) of X. fastidiosa CVC strain 9a5c were used to investigate transcript levels during growth with different iron availabilities. When treated with the iron chelator 2,2`-dipyridyl, 193 CDS were considered up-regulated and 216 were considered down-regulated. Upon incubation with 100 mu M ferric pyrophosphate, 218 and 256 CDS were considered up- and down-regulated, respectively. Differential expression for a subset of 44 CDS was further evaluated by reverse transcription-quantitative PCR. Several CDS involved with regulatory functions, pathogenicity, and cell structure were modulated under both conditions assayed, suggesting that major changes in cell architecture and metabolism occur when X. fastidiosa cells are exposed to extreme variations in iron concentration. Interestingly, the modulated CDS include those related to colicin V-like bacteriocin synthesis and secretion and to functions of pili/fimbriae. We also investigated the contribution of the ferric uptake regulator Fur to the iron stimulon of X. fastidiosa. The promoter regions of the strain 9a5c genome were screened for putative Fur boxes, and candidates were analyzed by electrophoretic mobility shift assays. Taken together, our data support the hypothesis that Fur is not solely responsible for the modulation of the iron stimulon of X fastidiosa, and they present novel evidence for iron regulation of pathogenicity determinants.

Desenvolvimento de sistemas magn��ticos com potencialidades terap��uticas para vetoriza����o de f��rmacos

Magnetic targeting is being investigated as a means of local delivery of drugs, combining precision, minimal surgical intervention, and satisfactory concentration of the drug in the target region. In view of these advantages, it is a promising strategy for improving the pharmacological response. Magnetic particles are attracted by a magnetic field gradient, and drugs bound to them can be driven to their site of action by means of the selective application of magnetic field on the desired area. Helicobacter pylori is the commonest chronic bacterial infection. The treatment of choice has commonly been based upon a triple therapy combining two antibiotics and an anti-secretory agent. Furthermore, an extended-release profile is of utmost importance for these formulations. The aim of this work was to develop a magnetic system containing the antibiotic amoxicillin for oral magnetic drug targeting. First, magnetic particles were produced by coprecipitation of iron salts in alkaline medium. The second step was coating the particles and amoxicillin with Eudragit�� S-100 by spray-drying technique. The system obtained demonstrated through the characterization studies carried out a possible oral drug delivery system, consisting in magnetite microparticles and amoxicillin, coated with a polymer acid resistant. This system can be used to deliver drugs to the stomach for treatment of infections in this organ. Another important finding in this work is that it opens new prospects to coat magnetic microparticles by the technique of spray-drying.

Strain variability in the DNA immigration control region (ICR) of Xylella fastidiosa

The genome of the bacterium Xylella fastidiosa contains four ORFs (XF2721, XF2725, XF2739 and XF0295) related to the restriction modification type I system, ordinarily named R-M. This system belongs to the DNA immigration control region (ICR). Each CIRF is related to different operon structures, which are homologues among themselves and with subunit Hsd R from the endonuclease coding genes. In addition, these ORFs are highly homologous to genes in Pseudomonas aeruginosa, Methylococcus capsulatus str. Bath, Legionella pneumophila, Helicobacter pylori, Xanthomonas oryzae pv. Oryzae and Silicibacter pomeroyi, as well as to genes from X. fastidiosa strains that infect grapevine, almond and oleander plants. This study was carried out on R-M ORFs from forty-three X. fastidiosa strains isolated from citrus, coffee, grapevine, periwinkle, almond and plum trees, in order to assess the genetic diversity of these loci through PCR-RFLP. PCR-RFLP analysis of the four ORFs related to the R-M system from these strains enabled the detection of haplotypes for these loci. When the haplotypes were defined, wide genetic diversity and a large range of similar strains originating from different hosts were observed. This analysis also provided information indicating differences in population genetic structures, which led to detection of different levels of gene transfer among the groups of strains. (c) 2005 Elsevier SAS. All rights reserved.

Esophageal and gastric biopsies in symptomatic children and adolescents. Should both be performed?

This study investigated the relationship among the histological diagnosis of esophagitis and gastritis in children and adolescents with gastroesophageal reflux disease (GERD) and/or dyspepsia. Records of 366 patients submitted to endoscopic biopsies were reviewed. Two groups were analyzed: G1 n=258 with esophageal and gastric biopsies, G2 n=108 with gastric biopsies only. For total subjects median age (range) was 8.5y (2mo-19.9y). Helicobacter pylori infection was detected in 30.6 %, median age 12.5y for H pylori-infected and 5.5y for uninfected children. Histological esophagitis was found in 216/258 (83.7 %) and gastritis in 95/258 (36.8 %) of G1. Both biopsies were normal for 13.6 % cases. Normal gastric biopsies were associated with esophagitis in 128/ 163 (78.5 %) of G1, but gastritis was associated with normal esophageal biopsies in only 7/95 (7.4 %) (0<.001). Histological gastritis was found in 80/108 (74.1 %) of G2 patients. Therefore, for symptomatic children both biopsies are indicated.

Qualea parviflora Mart.: An integrative study to validate the gastroprotective, antidiarrheal, antihemorragic and mutagenic action

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Byrsonima fagifolia: An integrative study to validate the gastroprotective, healing, antidiarrheal, antimicrobial and mutagenic action

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Can a Strychnos species be used as antiulcer agent? Ulcer healing action from alkaloid fraction of Strychnos pseudoquina St. Hil. (Loganiaceae)

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)