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R Buffa

Publications and source records attributed to R Buffa.

At least 73 records · Page 4Linked to original sources
PubMed1987

Anti-human tumor antibodies induced in mice and rabbits by "internal image" anti-idiotypic monoclonal immunoglobulins.

MBr1 is a murine monoclonal antibody, defining a saccharidic epitope [CaMBr1] of a human tissue-specific, tumor-associated globoside, present on the mammary carcinoma cell line MCF-7. The same epitope is shared by glycoproteins present on normal and neoplastic mammary epithelial cells, and by mucins from some ovarian cyst fluids. We have used MBr1 as the monoclonal antitumor antibody in an idiotypic sequence of immunizations in order to obtain and characterize "internal images" of the original epitope to be used as substitutes of the nominal antigen in serologic immunoassays. Two monoclonal anti-idiotypic antibodies (beta-1 and beta-2), which reacted with paratope-related idiotopes on MBr1, were obtained. The analysis of the antigenic and immunogenic properties of these molecules by both "antigen" and "antibody" competition assays provided evidence that both beta-1 and beta-2 bear "internal images" of the MBr1-defined epitope. Moreover, when injected in mice and rabbits both beta-1 and beta-2 induced anti anti-idiotypic antibodies, which mimicked MBr1 in binding MCF-7 as well as normal and neoplastic mammary gland epithelial cells. These data are discussed in terms of their possible application to the production of tumor-associated antigen substitutes and their use in serologic immunoassays.

Animals↗
PubMed1987

Endocrine cells producing regulatory peptides.

Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.

Animals↗
PubMed1987

Synaptophysin immunoreactivity and small clear vesicles in neuroendocrine cells and related tumours.

Synaptophysin (protein p38) immunoreactivity has been detected immunohistochemically in neuroendocrine cells of the human adrenal medulla, carotid body, skin, pituitary, thyroid, lung, pancreas and gastrointestinal mucosa as well as in 87 out of 93 neuroendocrine tumours investigated, including pheochromocytomas, chromaffin and non-chromaffin paragangliomas, ganglioneuromas, pituitary adenomas, thyroid medullary carcinomas, parathyroid adenomas, lung carcinoids and neuroendocrine carcinomas, pancreatic and gut endocrine tumours and cutaneous merkelomas. Parallel ultrastructural investigation of synaptophysin-reactive cells and tumours revealed the presence, in addition to dense-cored, secretory granules, of a population of pleomorphic, small, clear vesicles resembling synaptic vesicles of nerve terminals as well as the synaptophysin immunoreactive vesicles already described in rat adrenal medullary and pituitary cells. Synaptophysin immunoreactivity showed several differences in its distribution among tumour and non-tumour endocrine cells when compared to chromogranin A immunoreactivity, a well known marker of the core of endocrine granules. Synaptophysin represents a reliable general marker of neuroendocrine cells and tumours, which may be useful in diagnostic histopathology.

Chromogranin A↗
PubMed1986

Chromogranin A, B and C immunoreactivities of mammalian endocrine cells. Distribution, distinction from costored hormones/prohormones and relationship with the argyrophil component of secretory granules.

Antibodies specific for chromogranin A, B or C have been used to detect immunohistochemically these three anionic proteins. Pancreatic A, B and PP cells, gut argentaffin EC, argyrophil ECL and gastrin G cells, thyroid C cells, parathyroid cells, adrenal medullary cells, pituitary TSH, FSH and LH cells as well as some axons of visceral nerves have been found to react with chromogranin A antibodies. Pancreatic A, gut EC and G, adrenal medullary and pituitary cells as well as some gut nerve fibers showed chromogranin B immunoreactivity. Chromogranin C immunoreactivity has been detected in pancreatic A, pyloric D1, intestinal L, thyroid C, adrenal medullary and pituitary cells, as well as in some gut neurons and nerve fibers. No crossreactivity has been found in immunohistochemical tests between chromogranins A, B or C and costored monoamines or peptide hormones/prohormones, from which chromogranins can be separated by selective extraction during fixation. On both morphological and chemical grounds a relationship seems to exist between chromogranin A and Grimelius' argyrophilia. Sialooligosaccharide chains of chromogranin A and, possibly, chromogranins' phosphoserine/phosphothreonine groups, seem to interact with guanidyl, amino, and/or imidazole groups of non-chromogranin components to form silver complexing sites accounting for granules' argyrophilia, which can be removed or blocked without affecting chromogranin immunoreactivities. The abundant anionic groups of the three proteins should contribute substantially to granules' basophilia, the partly "masked" pattern of which supports the existence of a close interaction of such groups with other components of secretory granules, including monoamines and peptide hormones or prohormones. Chromogranins could play a rôle in hormone postranslational biosynthesis and intragranular packaging.

Adrenal Medulla↗
PubMed1986

[Bombesin and monoamine-containing cells of the rat stomach].

Revealing of enterochromaffine and enterochromaffine-like cells of the rat stomach was undertaken under the effect of bombesin and alpha- and beta-adrenoblocking agents. Fibers containing gastrin-releasing-peptide were immunohistochemically revealed in neural plexus of the rat digestive tract. Spontaneous rhythmic release of the stomach monoamine cells' secret was shown. The effect of bombesin on the enterochromaffine-like cells of the rat stomach fundus containing histamine, was shown to be actualized through beta-adrenoreceptors. Serotonin excretion from the enterochromaffine cells of the stomach antrum depends neither on bombesin nor on the adrenergic effects.

Animals↗
PubMed1985

Tryptophyllin-like immunoreactivity in rat adenohypophysis.

A new amphibian peptide family has been isolated from the skin of a South American frog Phyllomedusa rhodei and named Tryptophyllins (TPH) because of their content in tryptophyl residue. Using an antiserum against one of these peptides, namely the pentapeptide Met-5-TPH-5-amide (PHE-PRO-PRO-TRP-MET-NH2), we observed the presence of a set of immunoreactive cells in rat adenohypophysis. These cells were far more numerous in pregnant than in normal male and non-pregnant female rats. Dual immunostainings demonstrated that, with some exceptions, almost all the TPH-like immunoreactive cells were gonadotrophs. At electron microscope both types of gonadotroph cells displayed immunoreactivity and the gold particles strongly labelled both types of granules. The Aa. advance the hypothesis that, besides the hormones themselves, the secretory granules might contain some TPH-like sequence.

Animals↗
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

Morphologic patterns and diagnostic criteria of VIP-producing endocrine tumors. A histologic, histochemical, ultrastructural, and biochemical study of 32 cases.

Thirty-two tumors (31 pancreatic and one jejunal) all associated with severe watery diarrhea, increased VIP levels in blood and most with hypokalemia, were investigated. The VIP content of tumor tissue ranged from 23 to 15,000 pmol/g. VIP immunoreactive cells were detected histochemically in 24 of 28 tumors investigated, PP immunoreactive cells in 11 of 28 tumors, hCG (alpha chain) immunoreactive cells in 12 of 25 tumors, and neuron specific enolase (NSE) immunoreactive cells in 24 of 26 tumors (the 2 negative results were due to inadequate fixation). All cases showed light microscopic features of epithelial endocrine tumors. Electron microscopy demonstrated a prevalence of agranular, poorly granulated and a minority of well granulated cells. Most secretory granules were round, small (150+/- 30 nm diameter) and of moderate electron density, resembling those of the so-called D1 cells. By electron immunocytochemistry, PP was directly localized in a subpopulation of relatively larger granules (154 +/- 22 nm core diameter) showing closely applied membranes. VIP-storing granules, directly identified only in the jejunal tumor, appear to correspond to a subpopulation of slightly smaller P-type granules (126 +/- 37 nm core diameter) showing a narrow, clear halo. The origin, behavior, and diagnostic criteria of VIPomas are discussed.

Adult↗
PubMed1983

Alpha and beta subunits of glycoprotein hormones in argyrophil pituitary tumors with small granule cells.

A group of 33 functionless pituitary tumors with small argyrophil groups (SAG) were collected from a series of 200 pituitary adenomas (16.5% of all adenomas). Histologically, the tumors showed an unusually high frequency of trabecular patterns, perivascular pseudo-rosettes, and oncocytoid transformation. Immunoreactivity for glycoprotein hormone alpha-chain was found in more or less numerous cells of 20 cases (64.5% of SAG tumors). Thirteen of these cases also showed specific beta-chain immunoreactivity, especially for follicle-stimulating hormone (FSH) beta-chain, which was present in 11 tumors. Various admixtures of immature, oncocytic, sparsely granulated, and densely granulated cells were observed ultrastructurally, with prevalence of the latter cell variants in tumors showing immunoreactive cells and prevalence of the former cell variants in tumors lacking immunoreactive cells. It is suggested that some relationship may exist between SAG cell (glycoprotein hormone precursor cells?) tumors--or at least part of them--and glycoprotein hormone cell lines. Anyway, whatever their origin and interpretation, SAG cell tumors seem to represent a distinct clinicopathologic entity.

Adenoma↗
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 endocrine component of prostatic carcinomas, mixed adenocarcinoma-carcinoid tumours and non-tumour prostate. Histochemical and ultrastructural identification of the endocrine cells.

Two types of endocrine-paracrine (EP) cells have been detected histochemically and ultrastructurally in normal and hyperplastic prostates; i.e. type I cells resembling intestinal EC (enterochromaffin) cells and type 2 cells similar to urethral EP cells previously reported by Casanova et al. (1974). About one-third of the 40 prostatic carcinomas studied contained EP cells: two of these were composite tumours exhibiting both adenocarcinomatous and carcinoid patterns. These four tumours have also been studied histochemically and ultrastructurally. ACTH and beta-endorphin immunoreactive cells, ultrastructurally resembling pituitary corticotrophic cells, have been identified in three tumours. Cells identical with type I and type 2 cells of the normal prostate were detected in two cases and in a further case, respectively.

Adenocarcinoma↗
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

Immunohistochemical localization of polypeptides in peripheral autonomic nerves using whole mount preparations.

A method is described for the immunohistochemical localization of peptides in whole-mount preparations. Tissue is fixed as laminae with a picric acid/formaldehyde mixture and then dehydrated, cleared and rehydrated before exposure to antibodies. This procedure ensures adequate penetration of the antibody molecules without the need to freeze and thaw the tissue or to use detergents, preserves antigenicity and lowers non-specific background staining. The laminae are incubated with the primary antisera for 16 h at room temperature and, after washing, with a second, fluorescent tagged, antiserum. This can be followed by a peroxidase-anti-peroxidase localization of the second antiserum, which acts as a bridge. The method gives a precise and reproducible localization of immunoreactive peptides, with good penetration and low background even in thick preparation. Large areas can be scanned and neuroeffector relationships studied more easily than in sections.

Animals↗