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S Pena

Publications and source records attributed to S Pena.

7 recordsLinked to original sources
PubMed1999

Geographic distribution of vacA allelic types of Helicobacter pylori.

BACKGROUND & AIMS: Distinct allelic types of Helicobacter pylori vacA have been defined. The geographic distribution of vacA alleles and cagA was assessed in this study. METHODS: A total of 735 cultures from patients in 24 countries were analyzed by polymerase chain reaction and reverse hybridization on a line probe assay (LiPA). RESULTS: In 124 (16.9%) of the 735 cultures, multiple vacA genotypes were detected, permitting analysis of 611 strains. In Europe, a distribution gradient of s1 subtypes was observed. In northern and eastern Europe, 89% were subtype s1a. s1a and s1b were equally present in France and Italy, whereas in Spain and Portugal 89% of strains were subtype s1b. s1a and s1b were approximately equally prevalent in North America. In Central and South America, virtually all s1 strains were subtype s1b. Subtype s1c was observed in 77% of the s1 isolates from East Asia. m1 and m2a have equal presence, except on the Iberian peninsula and in Central and South America, where m1 (86.2%) is more prevalent than m2 (13.8%). Subtype m2b was found exclusively among East Asian s1c strains. In all parts of the world, vacA s1/cagA-positive genotypes were associated with peptic ulcer disease (P < 0.001). CONCLUSIONS: These data indicate a geographic distribution of H. pylori genotypes and aid in understanding the relationship of H. pylori with disease.

Alleles↗
PubMed1999

Oral budesonide for prevention of postsurgical recurrence in Crohn's disease. The IOIBD Budesonide Study Group.

BACKGROUND & AIMS: Prevention of postoperative recurrence after resection for Crohn's disease (CD) would be of great clinical benefit. The efficacy of oral budesonide for prevention of endoscopic recurrence was evaluated in patients undergoing resection for ileal or ileocecal CD. METHODS: Sixty-three patients received budesonide and 66 received placebo in a double-blind, randomized trial with parallel groups. Ileocolonoscopy, including biopsy, was performed after 3 and 12 months. Indications for surgery were fibrostenosis (78 patients), disease activity (41), and other reasons (10). RESULTS: The frequency of endoscopic recurrence did not differ between the groups at 3 and 12 months. In patients with disease activity as indication for surgery, the endoscopic recurrence rate at the anastomosis was lower in the budesonide group at 3 months, although not significantly (21% vs. 47%; P = 0.11), and at 12 months (32% vs. 65%; P = 0.047). There was no such difference with respect to fibrostenosis as indication for surgery. No differences in adverse event patterns were found between the two groups. CONCLUSIONS: Oral budesonide, 6 mg daily, offered no benefit in prevention of endoscopic recurrence after surgery for ileal/ileocecal fibrostenotic CD but decreased the recurrence rate in patients who had undergone surgery for disease activity.

Adolescent↗
PubMed1998

Expanding allelic diversity of Helicobacter pylori vacA.

The diversity of the gene encoding the vacuolating cytotoxin (vacA) of Helicobacter pylori was analyzed in 98 isolates obtained from different geographic locations. The studies focused on variation in the previously defined s and m regions of vacA, as determined by PCR and direct sequencing. Phylogenetic analysis revealed the existence of four distinct types of s-region alleles: aside from the previously described s1a, s1b, and s2 allelic types, a novel subtype, designated s1c, was found. Subtype s1c was observed exclusively in isolates from East Asia and appears to be the major s1 allele in that part of the world. Three different allelic forms (m1, m2a, and m2b) were detected in the m region. On the basis of sequence alignments, universal PCR primers that allow effective amplification of the s and m regions from H. pylori isolates from all over the world were defined. Amplimers were subsequently analyzed by reverse hybridization onto a line probe assay (LiPA) that allows the simultaneous and highly specific hybridization of the different vacA s- and m-region alleles and tests for the presence of the cytotoxin-associated gene (cagA). This PCR-LiPA method permits rapid analysis of the vacA and cagA status of H. pylori strains for clinical and epidemiological studies and will facilitate identification of any further variations.

Amino Acid Sequence↗
PubMedDate not supplied

Relationship of genotype and in vitro contractility in mdg/mdg in equilibrium +/+ "mosaic" myotubes.

Muscular dysgenesis (mdg) in the mouse is an autosomal recessive lethal disorder that is manifested by a gross failure of skeletal muscle development. In vitro mdg/mdg myoblasts proliferate normally and fuse successfully into myotubes, but these myotubes fail to contract either spontaneously or in response to physiological stimuli despite the presence of effective contractile elements and an ability to propagate action potentials normally. We have determined that mdg/mdg and +/+ myoblasts are capable of fusing in vitro to form "mosaic" myotubes which typically express an apparently normal contractile phenotype. Electrophoretic analysis of the relative activities of myotube glucosephosphate isomerase (GPI-1) isozymes provided a means of estimating the proportions of myonuclei of each genotype within individual myotubes. Only a very small proportion of genotypically normal myonuclei were required for expression of an apparently normal contractile phenotype.

Acetylcholine↗