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Biomedical subjects

R Buffa

Publications and source records attributed to R Buffa.

At least 55 records · Page 3Linked to original sources
PubMed1993

Different expression of chromogranin A and chromogranin B in various types of pituitary adenomas.

Two hundred and nineteen (33 GH, 21 GH-PRL, 38 PRL, 16 ACTH, 1 TSH cell functioning and 38 FSH-LH, 17 alpha-chain, 8 mixed, 27 minimal glycoprotein--MIN-GLYC--, 11 small argyrophil granule--SAG--, 4 silent TSH-sTSH--and 5 silent ACTH-sACTH--cell nonfunctioning) adenomas were investigated immunohistochemically with antibodies against ACTH, GH, PRL, TSH, FSH, LH alpha-hCG, chromogranin A (CgA) and chromogranin B (CgB). For immunostaining of CgB a novel monoclonal (B 11) antibody was employed. All types of adenomas were positive for CgB. CgA was widely expressed in nonfunctioning FSH-LH, MIN-GLYC, SAG, MIXED, alpha-chain adenomas and in the single TSH cell functioning adenoma. CgA was lacking both in PRL and ACTH functioning adenomas and was poorly expressed in GH and GH-PRL functioning adenomas. The distribution of Grimelius' silver paralleled that of CgA-IR, but not that of CgB-IR. We conclude that: 1) CgB may be considered as an universal granular marker for pituitary adenomas, 2) CgA is an important marker for nonfunctioning adenomas, 3) the pattern of distribution of CgA and CgB for most nonfunctioning ("null cell" according to Kovacs et al.) adenomas favors their origin from glycoprotein producing (FSH/LH, TSH) cells.

Adenoma↗
PubMed1992

Immunodetection of secretogranin II in animal and human tissues by new monoclonal antibodies.

Secretogranin II (chromogranin C) is an acidic tyrosine-sulfated secretory protein, known to be a marker of neuroendocrine secretory products and of specific neuroendocrine tumours. In order to obtain anti-secretogranin II monoclonal antibodies for cell biology studies and, in particular, for clinical applications, we immunized mice with a secretogranin II-enriched fraction prepared from homogenates of bovine anterior pituitaries. Hybridoma supernatants obtained from the splenocytes of a hyperimmune mouse, screened with an enzyme-linked immunosorbent assay, were analyzed by both immunocytochemistry and two-dimensional immunoblotting. By using this experimental approach, we were able to identify two monoclonal antibodies (8G1 and 5A7) which recognize bovine secretogranin II. Both immunocytochemistry and immunoblotting revealed that one of them, the 5A7 antibody, cross-reacts with the human antigen. The distribution patterns of the immunoreactivity, obtained by immunocytochemistry with the 5A7 antibody in animal and human tissues, partially overlap those, obtained by using a polyclonal antiserum elicited against bovine secretogranin II, previously described. Moreover, the 5A7, but not the polyclonal antibody, reacts with some duodeno-jejunal cells. In conclusion, both the 5A7 and 8G1 antibodies can be useful for cell biology studies. The 5A7 antibody can be used for the detection of secretogranin II in human tissues and should be of help in clinical and pathological practices.

Animals↗
PubMed1992

Gastrin (G) cells are the cellular site of the gastric thyrotropin-releasing hormone in human fetuses and newborns. A chromatographic, radioimmunological, and immunocytochemical study.

In this study we analyzed the ontogeny and location of gastric TRH in human fetuses, preterm and term newborns, and adults. TRH immunoreactive cells were found in the antrum towards the bottom of developing glands and double immunostaining demonstrated that this neuropeptide is coexpressed with gastrin in the same cell (G-cell). In the youngest fetuses studied (12 weeks) G cells were few and contained both gastrin and TRH. They increased in number during development and were most abundant between 26 and 36 weeks of gestation. These morphological data correlated with total immunoreactive TRH content extracted from the whole stomachs of six fetuses and two preterm infants. On the contrary G cells containing both hormones were decreased in the newborn at term and not identified in the adult whereas those containing only gastrin were numerous in both. The TRH extracted was indistinguishable from synthetic TRH using chromatographic, radioimmunologic, and enzymatic criteria. As has already been reported, TRH was found in insulin-containing cells of the islets of Langerhans in the pancreas of our fetuses and newborns. These cells presented a similar development pattern to the gastric G cells.

Adult↗
PubMed1990

Use of monoclonal antibodies to human breast-tumor-associated antigens in the diagnosis of fine-needle aspirates of breast nodules: results of a multicenter study.

Fine-needle aspiration (FNA) cytology is being increasingly employed in conjunction with physical examination and mammography in the pre-surgical diagnosis of breast nodules. In the present study, we have submitted to multicenter validation an immunocytochemical test which employs monoclonal antibodies (MAbs) to breast-tumor-associated antigens (BTAA) for the diagnosis of breast cancer. The results of this analysis, which has evaluated 846 FNAs, show that the immunological test has a sensitivity of 88.62%, a specificity of 97.9% and an accuracy of 92.4%. The predictive value of a positive and a negative finding were 98.4% and 85.57% respectively. Comparison between the cytological and immunocytochemical diagnosis displayed a higher sensitivity, accuracy and predictive value of a negative result with the latter method (p less than 0.01). Our findings clearly indicate that immunocytochemical methods can complement and improve the diagnostic accuracy of FNA cytology of breast nodules.

Antibodies, Monoclonal↗
PubMed1990

Classification and histogenesis of gastroenteropancreatic endocrine tumours.

A series of 267 gastroenteropancreatic endocrine tumours has been revised from the point of view of histopathologic diagnosis, hormonal profile and clinical behaviour. Results of this investigation, together with revised concepts on the histogenesis of gastroenteropancreatic endocrine growths, allowed to develop detailed classification systems which proved useful for precise tumour diagnosis and for clinicopathologic correlation, with special reference to tumour function, prognosis and therapy. Among 132 pancreatic growths, various types of islet cell tumours (61 cases), with (45 cases) or without (16 cases) hyperfunctional syndrome, were separated from different types of gut-related (38 cases) and 'ectopic' (three cases) tumours, as well as from 25 non-functioning, locally symptomatic tumours, three small cell carcinomas and two mixed endocrine-exocrine tumours. Among 97 intestinal tumours, 39 argentaffin EC cell carcinoids, mostly from the appendix and ileum, were separated from 23 hindgut-type carcinoids, mostly from the rectum, 22 gastrin cell tumours, mainly from the duodenal bulb, five somatostatin cell tumours, mostly from the periampullary region of the duodenum, and two gangliocytic paragangliomas. Among 38 gastric tumours, five small cell 'neuroendocrine' carcinomas were separated from three gastrin cell tumours and 30 argyrophil carcinoids, 27 of which arose in the body fundus, 16 associated with chronic atrophic gastritis and four with combined Zollinger Ellison/Multiple Endocrine Neoplasia Syndrome.

Biomarkers, Tumor↗
PubMed1990

Identification of the endocrine cells detected by the monoclonal antibody HISL-19 in human tissues.

The human endocrine cells reacting with the monoclonal antibody HISL-19 were identified with hormone antisera of proven specificity using a double immunostaining procedure. The epitope for HISL-19 was found in all types of pituitary cells except ACTH cells, in thyroid C cells, in all types of adrenal medullary and pancreatic islet cells and in somatostatin and pancreatic polypeptide cells of the gastrointestinal mucosa. No staining was found in parathyroid cells and in most gastrointestinal endocrine cells. Either paranuclear focal accumulation or diffuse cytoplasmic distribution of immunoreactive material were found. The spectrum of HISL-19 immunoreactive cells was found to be only in part complementary to that of cells immunoreactive for chromogranin A. Thus, it is concluded that the monoclonal antibody HISL-19 is a useful addition to other immunohistochemical markers for the detection of cells showing neuroendocrine features.

Adrenal Medulla↗
PubMed1989

Idiotypic replica of an anti-human tumor-associated antigen monoclonal antibody. Analysis of monoclonal Ab1 and Ab3 fine specificity.

CaMBr1 is a tissue-specific and tumor-associated saccharidic epitope, defined by mAb MBr1 (Ab1), expressed on glycoconjugates of the human mammary carcinoma cell line MCF-7 and of normal and neoplastic mammary epithelial cells. An anti-anti-idiotypic monoclonal Ab3, 2G-3, identifying a human breast tumor associated antigen, was raised by using as immunogen a mouse anti-idiotypic monoclonal Ab2, A3B10, which behaves as the internal image of CaMBr1. mAb 2G-3, as well as MBr1, defines a saccharidic epitope on glycoconjugates extracted from MCF-7 cells and shows MBr1-like reactivity on normal and neoplastic-tissues. Experimental evidence, however, suggests that the fine immunoreactivity of the two antibodies is not identical, because MBr1 has a preferential reactivity with glycolipids and 2G-3 with glycoproteins. We suggest that a possible biologic explanation for our findings could reside in the nature of the immunogens used to raise the two mAb (glycolipid vs protein "internal image").

Animals↗
PubMed1989

Calbindin 28 kDa in endocrine cells of known or putative calcium-regulating function. Thyro-parathyroid C cells, gastric ECL cells, intestinal secretin and enteroglucagon cells, pancreatic glucagon, insulin and PP cells, adrenal medullary NA cells and some pituitary (TSH?) cells.

The distribution of calbindin in some endocrine glands (thyroid, parathyroid, ultimobranchial body, pituitary and adrenals) and in the diffuse endocrine cells of the gut and pancreas has been investigated immunohistochemically using an antiserum raised against the 28 kDa calbindin from chicken duodenum. The identity of calbindin-immunoreactive cells in a number of avian and mammalian species was ascertained by comparison with hormone-reactive cells in consecutive sections or by double immunostaining of the same section with both calbindin and hormone antibodies. Calcitonin-producing C cells of the mammalian and avian thyroid, parathyroid or ultimobranchial body, PP, glucagon and insulin cells of the mammalian and avian pancreas, enteroglucagon cells of the avian intestine, secretin cells of the mammalian duodenum, histamine-producing ECL cells of the mammalian stomach, as well as noradrenaline-producing cells of the adrenal medulla and some (TSH?) cells of the adenohypophysis were among the calbindin-immunoreactive cells. Although some species variability has been observed in the intensity and distribution of the immunoreactivity, especially in the pancreas and the gut, a role for calbindin in the mechanisms of calcium-mediated endocrine cell stimulation or of intracellular and extracellular calcium homeostasis is suggested.

Animals↗
PubMed1989

Immunoreactivity of hormonally-characterized human endocrine cells against three novel anti-human chromogranin B(B11 and B13) and chromogranin A (A11) monoclonal antibodies.

Two novel monoclonal antibodies, called B11 and B13, directed exclusively against human chromogranin B (CgB) and another antibody, A11, specific for human chromogranin A (CgA), were obtained by immunization of mice with chromaffin granules, the fusion of their splenocytes, the screening of hybridomas supernatants by ELISA and immunohistochemistry, and characterization of the antibodies by two-dimensional immunoblotting. The antibodies were used in immunohistochemical tests to investigate the distribution of CgA and CgB in hormonally-identified cells of the human endocrine system. The A11 antibody confirmed the occurrence of CgA in gut EC, ECL, gastrin, secretin and neurotensin cells, pancreatic A and PP cells, parathyroid chief cells, pituitary TSH and gonadotrope cells and adrenal medullary cells. Only a fraction of CgA-immunoreactive cells in the human gut and pancreas showed C-terminus arginine-glycinamide immunoreactivity, suggesting pancreastatin storage. Both CgB antibodies showed immunoreactivity in gastrin cells, intestinal (but not gastric) EC cells, pancreatic A and PP cells, pituitary TSH and gonadotrope cells and adrenal medullary cells. In addition, the B11 antibody stained thyroid C cells and the B13 antibody stained the Golgi area of pituitary GH cells. It is concluded that most CgB is stored in the same cells showing CgA, although some CgA-rich cells, like gastric EC and ECL cells. lacked B11 and B13 immunoreactivities and some CgA-poor cells, like human thyroid C cells, showed intense B11 immunostaining.

Antibodies, Monoclonal↗
PubMed1988

Chromogranins A and B and secretogranin II in hormonally identified endocrine cells of the gut and the pancreas.

Chromogranins A and B and secretogranin II have been localized in a wide spectrum of gastroenteropancreatic endocrine/paracrine cells. Chromogranin A immunoreactivity showed the widest distribution and was displayed by glucagon-, PP-, gastrin-, gastrin-CCK-, secretin-immunoreactive cells, the most intense stainings being peculiar of enterochromaffin cells. Chromogranin B immunoreactivity was detected in gastrin- and glucagon cells and in some enterochromaffin cells containing also chromogranin A. Secretogranin II was paired to chromogranin A in glucagon cells of pancreatic islets or occurred alone in glycentin/PP cells of colonic mucosa. Neither of the chromogranins nor secretogranin II have been so far detected in somatostatin-, GIP-, or motilin-immunoreactive cells. Chromogranin A but not chromogranin B or secretogranin II has been detected in the gastric argyrophilic ECL cells.

Animals↗