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Biomedical subjects

R Fiocca

Publications and source records attributed to R Fiocca.

At least 109 records · Page 6Linked to original sources
PubMed1984

The contribution of immunohistochemistry to the diagnosis of neuroendocrine tumors.

The use of specific secretory products, hormones, and neuroregulators as diagnostic tools for neuroendocrine tumors is illustrated. Results of extensive immunohistochemical and cytologic investigations are discussed in the light of other pathologic and clinical findings to serve as a basis for tumor classification and as a help in prognostic evaluation. Endocrine tumors of the pancreas, gut, lung and urogenital tract are dealt in some detail.

Gastrointestinal Neoplasms↗
PubMed1983

Pancreatic polypeptide (PP) cells in the PP-rich lobe of the human pancreas are identified ultrastructurally and immunocytochemically as F cells.

The ultrastructure of immunohistochemically identified PP cells has been investigated by applying the serial semithin/thin section technique to the human pancreas, with special reference to the posterior part of the head, reputed to originate from the ventral primordium. PP cells of this area differ from those already identified in the rest of the pancreas and correspond to a cell, not yet described in the human pancreas, characterized by larger granules of very variable shape and structure. Such granules resemble those of so-called "F cells", i.e. the PP cells of dog uncinate process and cat duodenal lobe, also coming from the ventral primordium. Thus, human "ventral lobe" PP cells have peculiar potentialities which are expressed in distinctive structural patterns of presently unknown functional meaning.

Fetus↗
PubMed1983

The endocrine cells of the chicken proventriculus.

The endocrine cells of the chicken proventriculus were investigated by selective staining techniques, immunohistochemistry and electron microscopy. The following endocrine cell types were identified: 1) Argyrophilic ECL-cells, of unknown function, were very numerous in the 21-day-old chick, but less numerous in the newborn chick; 2) somatostatin-producing D-cells; 3) GLI-cells producing glucagon-related peptides; 4) X-cells of unknown function; 5) BN-cells producing bombesin; and 6) relatively few 5-hydroxytryptamine-producing EC-cells. Each of these cell types show a distinct morphology, distribution and histochemical reactivity. With the exception of BN-cells, they resemble rather closely the corresponding endocrine cell types previously described in the oxyntic mucosa (EGL, D, X and EC cells) or in the intestinal mucosa (L-cells) of the mammalian gut.

Animals↗
PubMed1982

Localization of bombesin and GRP (gastrin releasing peptide) sequences in gut nerves or endocrine cells.

Five anti-gastrin releasing peptide (GRP) sera have been characterized against GRP, bombesin and related polypeptides spotted on cellulose acetate discs. Antibodies reacting with the C-terminal G-14 sequence of bombesin and the 19-27 sequence of GRP, were detected in all sera. Antibodies directed exclusively against the bombesin unrelated 1-17 sequence of GRP were found only in one serum (R-6902). With parallel immunohistochemical tests only the C-terminal immunoreactivity was detected in endocrine-paracrine cells of the chicken proventriculus, while both immunoreactivities were present in nerve fibres and a few nerve cell bodies of the mammalian gut. The distribution of GRP- and bombesin-like immunoreactive nerves in the gastric mucosa of both pyloric and oxyntic type the submucosal and myenteric plexus along the whole gastrointestinal wall and at sphincter regions is detailed.

Animals↗
PubMed1981

The diffuse endocrine-paracrine system of the gut in health and disease: ultrastructural features.

At least 16 types of endocrine-paracrine cells have been identified ultrastructurally in the gastrointestinal mucosa. The production of hormones and local messengers such as 5-hydroxytryptamine, gastrin, cholecystokinin, somatostatin, secretin, gastric inhibitory peptide (GIP), enteroglucagon (glicentin, GLI), motilin, neurotensin, substance P and the enkephalins, by these cells, has been established. Progress has also been made in cytological studies of gut and pancreatic endocrine tumours. Argentaffin EC cell carcinoids, gastrinomas (of several ultrastructurally different varieties of gastrin cells), L-cell tumours and D-cell tumours are among those cytologically and functionally defined in the gut. Functionally undefined tumours include the so-called non-argentaffin carcinoids arising in various parts of the gut, some of which have been characterised cytologically as gastric ECL cell tumours and gastroduodenal P-D1-cell tumours. Gastrinomas, vipomas and rare argentaffin carcinoids are among gut-related pancreatic endocrine tumours. Non-functional paragangliomas, usually with some neuromatous component, occur in the duodenal wall. Extrapancreatic vipomas display ultrastructural features of ganglioneuroblastomas with peptidergic granules.

Animals↗
PubMed1980

Glucagon-, glicentin-, and pancreatic polypeptide-like immunoreativities in rectal carcinoids and related colorectal cells.

Three nonargentaffin rectal carcinoids have been investigated immunohistochemically. In one case most tumor cells reacted with antiglucagon sera as well as with antiglicentin, antibovine pancreatic polypeptide (BPP), and antihuman pancreatic polypeptide (HPP) sera; they were identified ultrastructurally as L cells. Another case showed glucagon-, glicentin-, and BPP-immunoreactive cells but lacked HPP immunoreactivity. In the third case glucagon- and glicentin-immunoreactive cells were well represented, while PP immunoreactivities were scarce. Parallel investigations of human rectal and sigmoid mucosa showed numerous cells reacting with glucagon, glicentin, and BPP antisera, most of which lacked HPP immunoreactivity. Cells reacting with glucagon and glicentin antisera, while lacking PP immunoreactivities, were also found. Thus, both tumor and nontumor cells produce glucagonlike immunoreactive (GLI) peptides--one of which may be glicentin or a related molecule--as well as PP-related sequences, although differing histochemically and ultrastructurally from glucagon or PP cells of the human pancreas. It is concluded that nonargentaffin rectal carcinoids are histogenetically linked to nonargentaffin endocrine cells of the human rectum.

Adult↗
PubMed1979

A rapid unfavorable outcome of Wegener's granulomatosis in early childhood.

Wegener's Granulomatosis was suspected in a 27-month-old female with a nodular, necrotizing lesion of the nose, diffuse subcutaneous nodules, and erythematous desquamation of the entire body. From 20 months of age on she had a purulent nasal discharge, recurrent infections of the upper and lower respiratory tract, a Coombs positive anemia, and enlargement of the spleen and liver. Treatment with azathioprine and corticosteroids produced transient improvement but three months later a dramatic relapse occurred. Cyclophosphamide was substituted for azathioprine but 10 days later the patient died and the autopsy confirmed the diagnosis of Wegener's Granulomatosis. The early age of onset of the disease may explain the unfavorable outcome, despite treatment with cytotoxic agents.

Adrenal Cortex Hormones↗
PubMed1979

Complement-mediated unspecific binding of immunoglobulins to some endocrine cells.

Unspecific binding of immunoglobulins to gastrin G cells, glucagon A cells and somatostatin D cells of the gastric mucosa or pancreas, as well as to the calcitonin-somatostatin cells of rabbit thyroid has been found to occur through a non antigen-antibody mechanism mediated at least in part by the C1q fraction of complement. The phenomenon represents a major drawback in hormone immunohistochemistry, which can be prevented by incubating the specific anti-hormone sera with anti-C1q antibodies or with complement-fixing immunocomplexes.

Animals↗
PubMed1979

Complement-mediated binding of immunoglobulins to some endocrine cells of the pancreas and gut.

Unspecific binding of immunoglobulins to gastrin, somatostain and glucagon cells of the gastrointestinal mucosa or pancreas has been found to occur through a nonantigen-antibody mechanism mediated by the C14 fraction of complement. The phenomenon represents an important drawback in hormone immunohistochemistry, which can be overcome by using complement deprived, highly dilute anti-hormone sera.

Animals↗
PubMedDate not supplied

Barrett's ulcer and Campylobacter-like organisms infection in a child.

Barrett's esophagus is a gastrointestinal metaplasia of the esophageal epithelium occurring frequently in adults with long-standing peptic esophagitis. Recent reports of Barrett's esophagus in children with gastroesophageal reflux (GER) showed that also at the pediatric age intestinal metaplasia of the esophagus may occur in association with peptic esophagitis. Recently a close association between Campylobacter-like organisms (CLOs) and gastritis has been found in the stomach of both adults and children with a variety of peptic diseases, but evidence of such infection in specimens of Barrett's epithelium has never been described in children. We report here a child with Barrett's esophagus and GER, treated with H2 blockers, who showed a Barrett's ulcer in association with CLO infection. The addition of amoxicillin to antireflux treatment was accompanied by healing of the ulcer, suggesting that bacterial infection of Barrett's epithelium may have an important role in determining its inflammation and possibly ulceration.

Barrett Esophagus↗
PubMedDate not supplied

Molecular mechanisms involved in the pathogenesis of gastric carcinoma: interactions between genetic alterations, cellular phenotype and cancer histotype.

Gastric cancer develops through the accumulation of multiple genetic lesions that involve oncogenes, tumor suppressor genes and DNA mismatch repair genes. Lauren's classification of gastric carcinoma does not correlate with cellular phenotypes expressed by neoplastic cells and gastric and intestinal cell differentiation markers are widely expressed in both types (intestinal and diffuse) of gastric carcinoma. In contrast, the study of the correlation between morphologic events and genetic alterations, which come about in the cancerogenetic process, seems to indicate the existence of distinct cancerogenetic pathways for the intestinal (or glandular) and diffuse type carcinoma, both originating from a HP-positive gastritis. In particular there seem to be three different profiles of cancerogenesis: 1) p53 mutations which accompany the onset of dysplasia and intestinal-type carcinoma; 2) DNA repair mechanism alterations conditioning microsatellite instability, seem mutually exclusive with regards to p53 mutations. Microsatellite instability correlates with antrally located intestinal-type carcinoma, with little metastatic tendency and a better prognosis; microsatellite instability frequently involves the TGF beta RII, IGF II R genes or the BAX proapoptotic gene, in as much as these contain microsatellite sequences; 3) alterations of E-cadherin, both with regards to mutations and abnormal expression. These lead to junctional and cell polarity loss and are primarily associated with diffuse type carcinoma, which is characterized by poorly cohesive neoplastic cells. Some tumors, initially arising as intestinal-type (glandular structure), acquire a mixed histotype during neoplastic progression, in which both the typical alterations of the intestinal cancerogenesis (p53, microsatellite instability) and those of the diffuse carcinoma (E-cadherin) coexist. The identification of a mixed histotype could have importance both in epidemiologic, pathogenetic and prognostic terms.

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↗