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At least 721 records · Page 40Linked to original sources
PubMed1996

[Microsatellite analysis].

Microsatellites are tandem iterations of simple di-, tri-, or tetranucleotides. They are very useful for the analysis of LOH (loss of heterozygosity) because they are highly polymorphic and interspersed throughout the genome. The microsatellite analysis also allows us to investigate the genetic instability, demonstrated as the expansion or contraction of repeat elements (replication error, RER), which might have resulted from the disruption of mismatch repair genes such as hMSH2 and hMLH1. The microsatellite analysis is a novel tool of genetic analysis which provides valuable information in the field of molecular oncology.

Chromosome Deletion↗
PubMed1996

Intestinal dissemination of gastric mucosa-associated lymphoid tissue lymphoma.

Despite increasing identification of concurrent gastric and intestinal lymphomas of mucosa-associated lymphoid tissue (MALT), the clonal relationship between the two tumors and their sequential development are poorly understood. It is also unknown whether the development of these concurrent tumors is closely associated with direct antigen stimulation, which is thought to play an important role in the clonal expansion of low-grade MALT lymphomas. To investigate these, we have studied six cases of concurrent gastric and intestinal MALT lymphomas by polymerase chain reaction (PCR) amplification, cloning, and sequencing of the rearranged Ig gene, a strategy that has been widely used for analysis of clonality and antigen-driven properties of B-cell malignancies. In each case, an identical or nearly identical complementarity determining region (CDR) 3 sequence was observed between the dominant clones of concurrent gastric and intestinal MALT lymphomas. In four of six cases examined, sufficient Ig variable region sequence information was obtained to permit analysis of somatic mutations. The mutation patterns in one case suggest that the intestinal lesion is secondary to the gastric tumor, and the mutation patterns in two cases indicate that the gastric and intestinal lesions are derived from different tumour subclones, which emerge after expansion of a common early tumor clone. Furthermore, three of four cases showed ongoing Ig mutations among different PCR clones at each site. These results show that concurrent gastric and intestinal MALT lymphomas are derived from the same clone and suggest that the intestinal lesions result from dissemination of gastric tumours. Antigen stimulation may play a role in tumor evolution, particularly at an early stage.

Amino Acid Sequence↗
PubMed1997

Endoscopic ultrasonography for esophageal and gastric mass lesions.

Endoscopic ultrasonography is a relatively new and evolving imaging modality incorporating endoscopy and ultrasonography into one comprehensive examination of the gut wall. Its principal indication has been the locoregional staging (T and N) of gastrointestinal tumors, particularly of the esophagus and stomach. Accuracy of conventional radiographic modalities (computed tomography and magnetic resonance imaging) has been disappointing (50-60%). Alternatively, the staging accuracy of the depth of tumor penetration (T stage) approaches 85-90% in most series, whereas that for lymph node assessment (N stage) has been in the 70-80% range. The precise stage of upper gastrointestinal neoplasms provides accurate pretreatment assessment of the patient's prognosis and may influence therapeutic decisions. Endosonography is also the diagnostic modality of choice in the evaluation of submucosal tumors. It can demonstrate size, layer of origin, and, by its echo texture, can accurately predict etiology of the neoplasm. The only limitation may be in the differentiation of benign from malignant smooth muscle tumors.

Diagnosis, Differential↗
PubMedDate not supplied

[Diagnostic imaging of liver metastasis].

The early diagnosis and monitoring of hepatic metastases are now achieved by different imaging modalities, some using ionizing radiations (computed tomography and angiography), some based on other energy sources (sonography and magnetic resonance), but all coming within the radiological area, which offers concrete possibilities of integration and the necessary organization. These modalities are sometimes used only for percutaneous histological samplings with minimal invasiveness. The progress in hepatic resective surgery and the possibility of orthotopic liver transplantation for some neoplastic histotypes, together with the alternatives provided by interventional radiology, have brought a continuous updating of the specialist' interest in the morphological and functional definition of hepatic metastatic disease, with the specific aim of choosing the best therapeutic strategy. Hepatic metastases have the greatest impact on the survival of patients with gastrointestinal neoplasms, especially colonic adenocarcinoma. Intraoperative sonography and CT arterial portography currently provide greatest diagnostic sensitivity in terms of spatial resolution but cannot be considered as methods of choice, the former for obvious reasons and the latter because of its invasiveness and complexity. The alternatives are to be sought in spiral CT and the new MR sequences which can undoubtedly provide a decisive improvement in the diagnostic standards currently available. Profoundly changed, but no less important, is the role of angiography, which still provides the anatomical support for hepatic surgery and the means for alternative treatments, such as chemoembolization and continuous infusional chemotherapy.

Angiography↗
PubMed1997

Helicobacter pylori and gastric cancer.

BACKGROUND: Considerable progress has been made over the past two decades in understanding gastric carcinogenesis. Genetic and environmental factors have been shown to play a part. Infection with Helicobacter pylori leads to chronic gastritis and evidence is accumulating to link this disease with the subsequent development of gastric cancer. METHOD: A literature review was undertaken using Medline (National Library of Medicine, Washington DC, USA) searches of the headings gastrointestinal neoplasms and H. pylori for the years 1993-1997; further relevant references were examined. RESULTS: H. pylori is implicated in gastric carcinogenesis. Proposed mechanisms centre on the inflammatory response of the gastric mucosa to the bacterium. CONCLUSION: Investigation is still required to elucidate the exact role of H. pylori in the development of gastric carcinoma. Eradication of the organism in high-risk groups might lead to a reduction in the incidence of gastric cancer.

Gastritis↗
PubMed1997

Classification of neuroendocrine tumors.

This article discusses the classification of neuroendocrine tumors with particular emphasis on pancreatic and gastrointestinal neoplasms. The classification system recently proposed by Capella et al. (Virchows Archiv 425: 547-560, 1995) is elucidated and further developed.

Humans↗
PubMed1976

Absence of correlation between spin-lattice relaxation times and water content in human tumor tissues.

With a view to ascertaining the possible role of water content of the cells in the reported elevated values for proton spin-lattice relaxation time (T1) in malignant tissues, measurements of percent water content as well as T1 were undertaken in 68 cases of normal and concerous tissues from diverse sites in human patients. T1 values for the uninvolved samples were found to lie in the range of 400-1000 msec while the corresponding range for the involved samples was from 450-1520 msec. Water content of both normal and uninvolved tissues mostly lay in the narrow range of 70-90%. Occasionally samples with large T1 values showed lower water content as well. Data obtained weakens the case for characterization of tumor cells on the basis of their water content alone.

Body Water↗
PubMed1991

Selected immunohistochemical markers in stromal neoplasms of the gastrointestinal tract.

We studied immunohistochemical reactions to vimentin, desmin and protein S-100 in 43 cases of stromal tumors of the gastrointestinal tract. The material studied included: 1 esophageal tumor, 18 gastric tumors, 19 small intestinal tumors and 5 colonic tumors, classified in 13 cases as benign and in 30 cases as malignant neoplasms of various degree of malignancy. Mean age of the patients was 58.9 years. A positive reaction to vimentin was found in 37 cases, a negative reaction concerned an esophageal tumor, two benign tumors (gastric and small intestinal) and three malignant tumors (gastric and two small intestinal). A positive reaction to desmin was detected in an esophageal tumor and in nine gastric tumors. Only one benign small intestinal tumor and three benign colonic tumors showed a positive reaction to desmin. Protein S-100 was found in an esophageal tumor and in 7 out of 18 gastric tumors and in 12 out of 24 intestinal tumors. Coexpression of vimentin and desmin was found in 8 gastric tumors, only in one small intestinal tumor and in three colonic tumors. Three gastric tumors showing both these reactions were all benign. Coexpression of desmin and protein S-100 was found in 7 out of 43 tumors of the alimentary tract. In six cases these tumors were benign. Basing on the results we may say that the presence of these antigens reflects the degree of differentiation of gastrointestinal stromal tumors of the gastrointestinal tract, though it does not allow to choose unequivocally conclusions as to their histogenesis.

Adult↗