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Biomedical subjects

A Corvalan

Publications and source records attributed to A Corvalan.

6 recordsLinked to original sources
PubMed2006

Nasal natural killer/T-cell lymphoma and its association with type "i"/XhoI loss strain Epstein-Barr virus in Chile.

BACKGROUND: Nasal T/natural killer (NK)-cell lymphoma is an aggressive type of non-Hodking's lymphoma associated with Epstein-Barr virus (EBV) and striking geographical variations worldwide. AIM: To characterise nasal NK/T-cell lymphoma associated with genotypes of EBV in Chile, a Latin American country, where multiple strains of EBV, including two new recombinant strains, in healthy individuals were recently found. METHODS: Cases with diagnosis of primary nasal lymphoma were selected for histological and immunohistochemical analysis (CD3, CD3e, CD4, CD8, CD79a, CD56, CD57 and TIA-1) and in-situ hybridisation, serology and genotyping analysis for EBV. RESULTS: Out of 22 cases, 9 (41%) cases fulfilled the World Health Organization criteria for nasal NK/T-cell lymphoma; of these 7 (78%) cases were positive for EBV. Genotyping analysis revealed 6 cases of type 1 EBV and wildtype F at the BamHI-F region, 4 cases type "i" EBV at the BamHI-W1/I1 region; XhoI wild type was found in 2 and XhoI loss in 4 cases, respectively. Cosegregation analysis of the BamHI-W1/I1 region and XhoI restriction site showed the new recombinant strain type "i"/XhoI loss in 3 cases and type "i"/XhoI wild-type strain in 1 case. Most patients were treated with combined anthracycline-containing regimens. Half of the cases attained complete remission. CONCLUSION: Although nasal NK/T-cell lymphomas from Chile share similar clinicopathological features, high association with EBV and unfavourable prognosis with those described elsewhere, genotype analysis shows that the new recombinant type "i"/XhoI loss strain might contribute to explain the intermediate incidence of nasal NK/T-cell lymphomas in Latin America.

Adult↗
PubMed2001

Epstein-Barr virus in gastric carcinoma is associated with location in the cardia and with a diffuse histology: a study in one area of Chile.

Epstein-Barr virus (EBV) has been associated with the most common form of stomach neoplasms, the gastric carcinoma (GC). The presence of EBV-encoded small RNAtype-1 (EBER-1), a marker for EBV infection was analyzed by in situ hybridization (ISH) in 185 formalin-fixed and paraffin-embedded cases of GC from a high risk region. We found 31 (16.8%) EBV-positive cases with no relationship to age. Although male predominance (19% in males and 12.5% in females) was observed, the gender difference did not achieve statistical significance. Odds ratio (OR) for cardia location was 5.4 (95% CI 1.7-17.3) when antrum was used as referent category and the effects of gender and age were taken into account. The proportion of EBV-positive cases in diffuse histology was higher than intestinal type (OR = 4.8, 95% CI = 2.0-11.1). Our findings are contrary to a previously accepted hypothesis, that high-risk countries for GC have low rates of EBV-associated GC. In addition, our findings regarding location, histology and weak male predominance are different from what has been described in Asian and European countries, but similar to those described in Mexico and Mexican descendants living in the U.S. suggesting unique characteristics of EBV-associated GC in Latin-America.

Adult↗
PubMed2001

Gastric permeability is not increased in children colonized by CagA-positive strains of Helicobacter pylori.

BACKGROUND: Sucrose permeability has been used as a marker to detect gastric lesions in children. As CagA status of Helicobacter pylori is an important factor in determining the evolution of the gastric lesion, CagA-positive strains being more frequently associated with severe mucosal lesions, the aim of this study was to determine the prevalence of CagA-positive strains in Helicobacter pylori-colonized children and to evaluate whether the sucrose permeability test might discriminate between colonization by CagA-positive or negative strains. PATIENTS AND METHODS: A series of 38 children (11.1+/-3.6 years) who required upper endoscopy for diagnostic purposes were included in the study. Endoscopy was carried out after the sucrose permeability test, and gastric biopsies were obtained for histologic examination, Helicobacter pylori detection by Giemsa staining and CLO-test, and determination of CagA status of the colonizing Helicobacter pylori strains by polymerase chain reaction. RESULTS: Helicobacter pylori was detected in 26 subjects (68.4%) and of these, 16 (61.5%) were colonized by CagA-positive strains. The intensity of the histologic findings was significantly associated with the presence of Helicobacter pylori and with CagA status of the infecting strains (chi2=21.2, p=0.0017). However no significant difference in the urinary excretion of sucrose between children not colonized and children with CagA- negative or positive strains was observed (0.027% [0.012-0.035%]; 0.027% [0.016-0.047%] and 0.026% [0.016-0.038], median [range], respectively; Kruskal-Wallis analysis of variance F=0.75, p=0.69). CONCLUSIONS: These results indicate that in Chile, about 60% of the Helicobacter pylori infected children are colonized by CagA-positive strains, in association with more intense lesions of the gastric mucosa, but that gastric permeability to sucrose does not discriminate between colonization by CagA-negative and positive strains of Helicobacter pylori.

Abdominal Pain↗
PubMed1992

Percutaneous vascular hemostasis device for interventional procedures.

A new 11.5F over-the-wire vascular hemostasis device was compared to conventional manual compression in normal swine femoral arteries. Using percutaneous techniques, the collagen was deposited and hemostasis achieved in 7 vessels after 1 minute total, plus 4 minutes partial compression, while control manual compression required more than 5 minutes total compression to avoid hematoma formation. One month follow-up of treated arteries (n = 4) and controls (n = 3) showed no impairment in distal pulse or differences in histology at the puncture site in the control and treated arteries. Thus, the vascular hemostasis device technique is safe and effective, achieves hemostasis with less compression time and complications, and does not interfere with arterial wall healing or compromise the lumen.

Angioplasty, Balloon↗