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Biomedical subjects

R Fiocca

Publications and source records attributed to R Fiocca.

At least 73 records · Page 4Linked to original sources
PubMed1994

Epithelial cytotoxicity, immune responses, and inflammatory components of Helicobacter pylori gastritis.

To clarify the mechanisms of the gastric mucosal immune--inflammatory response to Helicobacter pylori infection, surgical and biopsy specimens from asymptomatic uninfected, gastritis-free individuals and from H. pylori-positive ulcer patients with chronic gastritis were investigated using light and electron microscopy. Activation of the antigen-transporting endocytic--endosomal system, enhanced expression of the antigen-processing enzyme cathepsin E and de novo expression of antigen-presenting human leukocyte antigen (HLA)-DR molecules have been detected in H. pylori-colonized gastric epithelium. These findings may be crucial in the production of a mucosal immune-inflammatory response to H. pylori infection. Cytoplasmic swelling and vacuolation, micropapillary change, mucin loss, erosion of the juxtaluminal cytoplasm and cell desquamation were the main effects of bacterial cytotoxicity on gastric surface-foveolar epithelium. Activated macrophages and granulocytes (partly linked to the mucosal IgG immune response) concentrate in the foveolar-neck region of the mucosa, where they may enhance damage and impair regeneration of the epithelium. Both direct bacterial cytotoxicity and inflammatory cell aggression against gastric epithelium may predispose the patient to peptic ulcer disease.

Eosinophils↗
PubMed1994

Effects of eradication of Helicobacter pylori on gastritis in duodenal ulcer patients.

The incidence and mean score of Helicobacter pylori-related, active antroduodenitis, lesions of superficial antral epithelium and duodenal gastric-type metaplasia were higher in endoscopic biopsies from a large series of patients with duodenal ulcer, when compared with asymptomatic patients or patients with non-ulcer dyspepsia. In 65 out of 73 patients with duodenal ulcer who could be followed up, H. pylori was eradicated using a combination of amoxycillin, 3 g daily, metronidazole, 1 g daily, and omeprazole, 20 mg daily. Rapid and permanent (6-month follow-up) abolition of both gastroduodenitis activity and lesions of the gastric surface epithelium was observed in these 65 patients. There was also a progressive decrease in total immune-inflammatory cells but without a substantial change in duodenal gastric-type metaplasia. Similar, but transient and quantitatively less prominent, improvements were observed in the antroduodenal mucosa, which had been temporarily cleared of H. pylori by treatment with omeprazole alone. Conversely, increased gastritis activity, epithelial lesions and immune-inflammatory cell scores were found in the short term in the corpus mucosa, which was not cleared of H. pylori after omeprazole treatment. It is concluded that, of the various H. pylori-related mucosal changes, antroduodenitis activity and antral epithelial lesions most closely reflect the severity of mucosal damage and are probably the most important factors in duodenal ulcerogenesis. Their complete and rapid suppression after bacterial eradication may be a key factor in preventing ulcer relapse.

Amoxicillin↗
PubMed1994

Coexpression of aspartic proteinases and human leukocyte antigen-DR in human transplanted lung.

Aspartic proteinases have recently been shown to be implicated in antigen processing. We explored the expression of two aspartic proteinases, cathepsins E and D, and of human leukocyte antigen-DR (HLA-DR) molecules in a consecutive series of 80 transbronchial biopsies from transplanted lungs. For controls, we studied five normal donor lungs (not suitable for transplantation on account of thoracic trauma) and macroscopically normal areas of three cancer-affected lungs. Two of the five unsuitable donor lungs showed minimal inflammatory changes. Macroscopically normal samples from the three cancerous lungs showed mild and focal inflammatory infiltrates. In histologically normal lungs, HLA-DR expression was limited to professional antigen-presenting cells. Macroscopically normal lung samples with minimal inflammatory changes from both donor and cancer lungs showed variable HLA-DR expression by alveolar and bronchial epithelial cells and by endothelial cells. All transplanted lung biopsies showed HLA-DR expression by epithelial (alveolar and bronchial) and endothelial cells, with a trend for increased positivity in acute rejection. Cathepsin E was restricted to Clara and to rare bronchus-associated lymphoid tissue-related epithelial cells in histologically normal lung samples, whereas minimal de novo cathepsin E expression by rare alveolar pneumocytes was noted in control lung samples exhibiting minimal inflammatory changes. In all transplanted lung biopsies, cathepsin E was diffusely expressed de novo by hyperplastic alveolar epithelial cells, regardless of the presence or degree of rejection. Cathepsin D was expressed only by alveolar macrophages and by ciliated bronchial cells of normal, minimally inflamed, and transplanted lungs. In transplanted lung, Clara cells and several hyperplastic alveolar pneumocytes coexpressed HLA-DR and cathepsin E, whereas all alveolar macrophages and a few ciliated cells coexpressed cathepsin D and HLA-DR. The present investigation suggests that the de novo expression of cathepsin E and HLA-DR by hyperplastic alveolar pneumocytes of transplanted lung may be crucial for antigen processing and presentation to recipient competent T cells, and thus for the triggering of the immune-inflammatory cascade that leads to rejection.

Acute Disease↗
PubMed1993

Na+,K(+)-ATPase of gastric cells. A target of Helicobacter pylori cytotoxic activity.

The present study shows a direct impairing action of a cytotoxin-producing Helicobacter pylori strain on the Na+,K(+)-ATPase (evaluated as K(+)-dependent phosphatase activity) of human gastric epithelial cells in culture. The toxin itself is likely involved in this action which may also account for the cell edema found in vivo in Helicobacter pylori-colonized stomach.

Adenocarcinoma↗
PubMed1993

Cathepsin E in follicle associated epithelium of intestine and tonsils: localization to M cells and possible role in antigen processing.

A specific rabbit anti-human serum was used selectively to localize the aspartic proteinase cathepsin E to follicle associated epithelium (FAE) of human and rat intestine, including jejunum, ileum, appendix, colon and rectum, as well as of human palatine, pharyngeal and lingual tonsils. Coexpression of class II histocompatibility antigen HLA-DR antigen has been observed in some of the cathepsin E-positive epithelial cells. In addition, cathepsin E has been detected in a few mononuclear cells of intestinal lymphoid structures and tonsils resembling interdigitating reticulum cells of lymph nodes. Another aspartic proteinase, cathepsin D, has been found to be poorly represented in FAE and intensely expressed by macrophages. Electron immunocytochemistry localized cathepsin E to endosomal vesicles and endoplasmic reticulum of M cells in rat and human ileum as well as of M-like cells in human palatine tonsil. The results suggest a possible role of endosomal cathepsin E in the processing of macromolecules and microorganisms transported by M cells and related epithelial cells to mucosal associated lymphoid tissue (MALT).

Adolescent↗
PubMed1993

Mosaic differentiation of human villus enterocytes: patchy expression of blood group A antigen in A nonsecretors.

BACKGROUND: The authors have shown that a mosaicism of brush border antigens may occur spontaneously on enterocytes of small intestine in human adult-type hypolactasia. The present paper gives another example of spontaneously occurring mosaicism as indicated by the patchy expression of blood group antigens on villus enterocytes. METHODS: Thirty-five individuals were examined by immunomorphological techniques with antibodies against blood group antigens. RESULTS: In 4 of 16 A blood group individuals, the blood group antigens were expressed only in some villus enterocytes. The individuals with this mosaic pattern were all shown to be nonsecretors. The A antigen in the positive enterocytes of these individuals was only present as the ALe(b) structure, whereas ALe(y) and ALe(d) were also present in the secretors. The patches of positive enterocytes were randomly distributed along the villus wall. CONCLUSIONS: A nonsecretor individuals express the blood group antigens only in some villus enterocytes; this mosaicism does not arise from a heterogeneous population of stem cells within the crypts but rather reflects subtle differences in the pattern of differentiation between monoclonally derived epithelial cells on the villus.

ABO Blood-Group System↗
PubMed1993

Proton pump inhibitors, enterochromaffin-like cell growth and Helicobacter pylori gastritis.

In both rodents and humans the development of gastrin-promoted gastric argyrophil enterochromaffin-like cell carcinoids requires the involvement of a genetic factor inherent to multiple endocrine neoplasia syndrome or of type A autoimmune chronic atrophic gastritis. Prolonged severe hypergastrinaemia acting on non-gastritic mucosa, as in Zollinger-Ellison syndrome patients, results in diffuse argyrophil enterochromaffin-like cell hyperplasia but, as a rule, does not produce tumours. Combination of chronic atrophic gastritis (mostly related to Helicobacter pylori infection) with hypergastrinaemia frequently causes linear and micronodular hyperplasia of argyrophil cells, whereas carcinoids are exceptional. No tumours or pre-neoplastic lesions have been observed in patients treated long-term with proton pump inhibitors, apart from rare cases in patients with combined Zollinger-Ellison and multiple endocrine neoplasia syndromes. A moderate increase in the incidence of argyrophil cell clustering, with or without hyperplasia, probably results from the parallel evolution of ulcer-associated Helicobacter gastritis into chronic atrophic gastritis. Eradication of H. pylori with a combination of proton pump inhibitors and antibiotics suppresses gastritis and prevents ulcer recurrence.

Animals↗
PubMed1993

Aspartic proteinases in normal lung and interstitial pulmonary diseases.

Two aspartic proteinases, pepsinogen II (PgII) and cathepsin E (CathE), were identified immunocytochemically in lung epithelia. In normal lung, type II pneumocytes were characterized by PgII immunoreactivity of variable intensity, while bronchiolar Clara cells reacted with CathE antibodies. With the exception of small groups of nonciliated bronchial cells overlying lymphoid follicles, no other CathE-immunoreactive cell was found in the lung. Immunoblots of crude protein extracts of lung tissue using PgII and CathE antibodies showed reactivity with single molecular species co-migrating with analogous bands obtained from gastric mucosa (molecular weight, 40,500 for PgII and 42,000 to 44,000 for CathE). In 75 cases of non-neoplastic lung disease, a highly significant correlation was found between the severity of histopathologic lesions and expression of both PgII (P < 0.001) and CathE (P < 0.001). Epithelial hyperplasia contributed more than inflammation and fibrosis to this relationship. Proteinase overexpression was not specific to any particular disease and was found in both focal and diffuse lesions. Segregation of PgII and CathE in different cells was lost in hyperplastic epithelium, where coexpression of both proteinases by the same cell was frequently observed. The location of both proteinases in distal airways and their enhanced expression in the proliferative, hyperplastic phase of several non-neoplastic pneumopathies suggest their possible involvement in the process of parenchymal remodeling that occurs in fibrosing lung diseases.

Cathepsin E↗
PubMed1993

Cathepsin E in antigen-presenting Langerhans and interdigitating reticulum cells. Its possible role in antigen processing.

A specific rabbit anti-human cathepsin E serum detected this aspartic proteinase in Langerhans cells of the skin, in interdigitating reticulum cells of lymph nodes and spleen and in histiocytosis X cells, but not in macrophages. Immunoblotting of tissue extracts confirmed the presence of cathepsin E in skin and lymph nodes. Electron immunocytochemistry with the protein A gold technique localized cathepsin E in the endoplasmic reticulum and in endosomal vesicles of both interdigitating and Langerhans cells, likely involving Birbeck bodies. A role of endosomal cathepsin E in antigen processing is suggested.

Cathepsin E↗
PubMed1993

The pathology of the gastrointestinal endocrine system.

Among endocrine tumors occurring in the gastrointestinal tract, midgut argentaffin EC cell carcinoids, gastric argyrophil ECL cell carcinoids, duodenal gastrin cell tumors, and rectal trabecular L cell carcinoids (in order of decreasing frequency) are those occurring more frequently. Together, they account for more than 80% of such tumors. Duodenal somatostatin cell tumors, gangliocytic paragangliomas, and differentiated neuroendocrine carcinomas are also well-defined tumor entities. The carcinoid syndrome, either classical, with intermittent flushing, hypotension, and diarrhea, or atypical, with persistent histamine-type red flushing, bronchospasm, and no diarrhea, and Zollinger-Ellison syndrome, with severe peptide ulcer disease, are the only hyperfunctional syndromes consistently found in association with these tumors. The carcinoid syndrome occurs in about 10% of gastrointestinal carcinoids, usually in their advanced, metastatic stage. The Zollinger-Ellison syndrome occurs in association with about 40% of intestinal gastrin cell tumors, including small intramural growths. Tumor prognosis depends on the mode and site of presentation, histology, cell type(s), size, level of invasion, metastases (especially distant metastases), and associated clinical syndrome or background disease. Hormones, trophic factors, inherited genetic traits, somatic mutations, and some chronic inflammatory processes are pathogenetically important in a large proportion of cases.

Animals↗
PubMed1992

Helicobacter colonization and histopathological profile of chronic gastritis in patients with or without dyspepsia, mucosal erosion and peptic ulcer: a morphological approach to the study of ulcerogenesis in man.

Helicobacter pylori colonization and the incidence, severity, activity and topography of gastritis were investigated systematically in antrum and corpus mucosal biopsies of 1177 subjects undergoing endoscopy in the absence of gastric complaints (asymptomatic, 49) or for non-ulcer dyspepsia (NUD; 631 patients, 72 of whom had gastric and/or duodenal erosions), active gastric ulcer (GU, 76 patients), active duodenal ulcer (DU, 138 patients), and healed gastric (HGU, 39 cases) or duodenal ulcer (HDU, 230 cases). In the antrum, H. pylori colonization and the incidence, severity and activity of gastritis increased progressively in the sequence asymptomatic, erosion-free NUD, erosive NUD, healed ulcer and active ulcer. The same trend was observed in the corpus as regards H. pylori and gastritis incidence, whereas the severity and activity of gastritis were lower in active DU and erosive NUD and higher in active, proximal GU than in the remaining patients. Active DU and erosive NUD showed the highest incidence of non-atrophic gastritis and lowest type-A or AB atrophic gastritis, while active GU had lowest normal mucosa or type-A gastritis and highest type-B atrophic gastritis. In conclusion, H. pylori colonization and gastritis incidence, severity and, especially, activity of the antrum might all contribute to mucosal erosion and ulceration, whereas the same factors, at least in part and with the exception of proximal GU, seem to have a preventive role when affecting corpus mucosa.

Adolescent↗
PubMed1992

Gastric endocrine cells and gastritis in patients receiving long-term omeprazole treatment.

Both argyrophil endocrine cells and gastritis were investigated in 2,120 biopsies of gastric corpus mucosa from 443 out of 448 patients receiving long-term (for periods ranging from several months to 4 years) omeprazole treatment. None of the patients showed neoplasia or dysplasia, either endocrine or non-endocrine. In 123 out of 443 patients (27.8%), endocrine hyperplasia of diffuse (9.3%), linear (4.1%) or micronodular (14.4%) type was detected either before or at some time during treatment. Chronic atrophic gastritis was found in 45 (10.2%) patients, 60% of whom also showed micronodular hyperplasia. In patients with chronic atrophic gastritis, micronodular hyperplasia occurred in 49% of 96 biopsies, compared with 6% of 1,083 biopsies from patients with non-atrophic chronic gastritis and 2% of 941 biopsies from patients with no evidence of gastritis. In 202 patients treated with omeprazole for at least 330 days, the incidence of micronodular hyperplasia increased from 2.5% at the first biopsy to 10.4% at the final biopsy, while the incidence of chronic atrophic gastritis increased from 1.0% to 13.0%. The present and parallel studies suggest that progression of gastritis is inherent in the natural history of acid-related diseases, while endocrine cell changes are mostly secondary to gastritis-related gland atrophy and have no tumorigenic potential.

Adult↗
PubMed1991

Mosaic pattern of lactase expression by villous enterocytes in human adult-type hypolactasia.

Immunohistological analysis of the expression of lactase protein in adults with hypolactasia has been carried out using monoclonal antibodies. Eight different antibodies that recognize at least three distinct epitopes on the lactase protein each gave the same result. Strong brush border staining was observed in all the lactase-persistent adults. No staining at all was detected in 9 of the hypolactasic subjects. In the remaining 12 individuals a mosaic pattern of expression was observed: small patches of enterocytes stained strongly, whereas the surrounding areas showed no staining at all. Sucrase-isomaltase, in contrast, showed no such mosaicism in these or in any of the other individuals. The mosaicism observed in the 12 hypolactasic individuals suggests that the differentiation of the columnar cells along the villus is not homogeneous. Furthermore, the existence of two patterns of expression of the lactase protein in the lactase-deficient individuals (i.e., absence of protein and mosaicism), if characteristic of the entire length of the intestine of the individuals tested, would suggest the existence of two phenotypes of adult-type hypolactasia in the population studied.

Antibodies, Monoclonal↗
PubMed1991

Morphology and pathogenesis of endocrine hyperplasias, precarcinoid lesions, and carcinoids arising in chronic atrophic gastritis.

The spectrum of endocrine cell changes occurring in 80 cases of body-fundus chronic atrophic gastritis (CAG), mostly type A or multifocal, including various types of hyperplasia, precarcinoid lesions (20 cases), and neoplasia (carcinoid, 24 cases) have been analyzed histologically, histochemically, and ultrastructurally. Changes associated with gland atrophy, pyloric- or intestinal-type metaplasia, regenerative hyperplasia, and hypergastrinemia have been identified and their neoplastic potential evaluated in the light of their proliferative capacity (bromodeoxyuridine incorporation) and clinicopathologic behavior. A close link between disseminated precarcinoid lesions of non-tumor mucosa and multiple carcinoids (carcinoidosis) arising in hypergastrinemic type-A CAG is suggested. Hyperplastic changes, including endocrine cell clusters, seem to have no or only minimal neoplastic potential.

Carcinoid Tumor↗
PubMed1990

The foveolar cell component of gastric cancer.

M1, a mucin antigen, and cathepsin E, an aspartic proteinase, are both expressed in normal gastric superficial-foveolar epithelial cells. In this study, we determined by immunohistochemical staining the prevalence of these antigens in 316 gastric cancers representative of the main histologic types and stages of the disease. M1 was expressed in 201 cases (64%) and cathepsin E was expressed in 235 cases (75%) of the 313 cases investigated. Both antigens were expressed more commonly in diffuse and mixed cancers than in glandular tumors. M1 was found in 64 of 83 (77%) diffuse cancers and in 48 of 59 (81%) mixed cancers, but in only 74 of 146 (51%) glandular cancers. For cathepsin E, the prevalence was 93% in diffuse cancer, 81% in mixed cancer, and 71% in the 143 glandular cancers examined. Among 25 mucoid tumors, 15 (60%) expressed M1 but only eight (32%) expressed cathepsin E. Overall, 262 (84%) of the tumors expressed at least one of these antigens and of these, 173 (66%) expressed both antigens. No significant difference in the prevalence of M1 or cathepsin E was found between early and advanced cancer or between metastatic and nonmetastatic cancer. The two markers differed in their intracellular localization. In superficial-foveolar cells, M1 immunostaining was concentrated in secretory granules, Golgi complex, and luminal mucous, whereas cathepsin E was found in the endoplasmic reticulum. Moreover, cathepsin E, but not M1, was found in the enterocytes of duodenal villi and, occasionally, in mucopeptic cells. Parallel histochemical and ultrastructural investigations confirmed the occurrence in gastric cancer of foveolar-type cells, manifested by periodic acid-Schiff- and/or alcian blue-reactive mucous granules having a punctate substructure. We conclude that superficial-foveolar cell differentiation is common in gastric cancer and is a major component of this type of tumor. However, pure foveolar cell differentiation is rare. Rather, most gastric cancers consist of cells exhibiting features of foveolar, intestinal, and mucopeptic cell lines.

Antibodies↗