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G Rindi

Publications and source records attributed to G Rindi.

188 records · Page 11Linked to original sources
PubMedDate not supplied

Thiamin uptake by rat isolated enterocytes: relationship between transport and phosphorylation.

The membrane and intracellular steps of thiamin (T) uptake were studied in rat isolated enterocytes. The membrane step was investigated by using enterocytes deenergized with 25 microM rotenone and a short (30 s) incubation time, while the intracellular metabolic step was assessed by using normoenergized (normal) cells incubated for a longer (30 min) time. Evaluation of Km, Jmax and KD (apparent passive permeability coefficient) values, at 30 s incubation, indicated that deenergization slightly reduced both the affinity and the capacity of the saturable component of T uptake, as well as the capacity of the non-saturable component. At 30 min incubation, deenergization suppressed completely the saturable component, without affecting the non-saturable component. Comparison of the Km and Jmax values of the saturable components in normoenergized enterocytes at 30 s and 30 min indicated that intracellular metabolic phosphorylation is probably the event responsible for the active process involved in T uptake.

Animals↗
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Natural history, clinicopathologic classification and prognosis of gastric ECL cell tumors.

A series of 50 gastric endocrine tumors classified according to Rindi et al. [1] comprised 12 small cell neuroendocrine carcinomas (NEC) and 38 ECL cell carcinoids, of which 22 associated with type A chronic atrophic gastritis (A-CAG), eight with hypertrophic gastropathy due to combined Multiple Endocrine Neoplasia and Zollinger/Ellison syndrome (MEN/ZES), and eight sporadic. Variables found to predict tumor malignancy were: size > 2 cm, > 2 mitoses and > 130 Ki67 positive cells/10 high power fields (HPF), grade 2 or 3 histology, angioinvasion, p53 protein nuclear accumulation, and the presence of a single tumor. None of these factors increased significantly the predicting ability of tumor classification itself, although grade 2 + 3 shows 100 percent negative predictive value and Ki67 and angioinvasion 100 percent positive predictive value. When the mostly non-malignant A-CAG and MEN-ZES tumors were analysed against the mostly malignant sporadic and NEC tumors, a positive predictive value of 90 percent and a negative predictive value of 93 percent was obtained. Investigation of a larger tumor series is under way with the aim to develop an optimal model for prognostic evaluation of gastric endocrine tumors.

Adult↗
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Abnormal gastric morphology and function in CCK-B/gastrin receptor-deficient mice.

Mice lacking the cholecystokinin (CCK)-B/gastrin receptor have been generated by targeted gene disruption. The roles of this receptor in controlling gastric acid secretion and gastric mucosal growth have been assessed. The analysis of homozygous mutant mice vs. wild type included measurement of basal gastric pH, plasma gastrin concentrations as well as quantification of gastric mucosal cell types by immunohistochemistry. Mutant mice exhibited a marked increase in basal gastric pH (from 3.2 to 5.2) and about a 10-fold elevation in circulating carboxyamidated gastrin compared with wild-type controls. Histologic analysis revealed a decrease in both parietal and enterochromaffin-like (ECL) cells, thus explaining the reduction in acid output. Consistent with the elevation in circulating gastrin, antral gastrin cells were increased in number while somatostatin cells were decreased. These data support the importance of the CCK-B/gastrin receptor in maintaining the normal cellular composition and function of the gastric mucosa.

Animals↗
PubMedDate not supplied

Distinct patterns of chronic gastritis associated with carcinoid and cancer and their role in tumorigenesis.

A series of 60 gastric endocrine tumors comprised 44 body-fundus argyrophil carcinoids, of which 23 arose in a background of hypergastrinemia and type A chronic atrophic gastritis (A-CAG), mainly with histologic patterns suggestive of an autoimmune process. Only 22 percent (compared with 19 percent of 58 tumor-free A-CAG cases) of 36 carcinoids and 21 percent of 19 A-CAG carcinoids investigated had Helicobacter pylori (HP) colonization, against 50 percent of 14 CAG-associated neuroendocrine carcinomas or mixed endocrine-exocrine tumors, 84 percent of 150 cases with early gastric cancer (p < 0.001 versus carcinoids), mostly with B- or AB-type CAG, 76 percent of 97 tumor-free AB-CAG, and 95 percent of 151 tumor-free B-CAG cases. Secondary hypergastrinemia and local mechanisms activated by chronic autoimmune gastritis are among factors involved in the pathogenesis of relatively indolent CAG-associated carcinoids, whereas active HP gastritis in cooperation with environmental carcinogens may likely cause more severe epithelial transformation, leading to ordinary cancer and, possibly, to neuroendocrine carcinomas or mixed endocrine-exocrine tumors.

Autoimmune Diseases↗