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G Zamboni

Publications and source records attributed to G Zamboni.

At least 19 recordsLinked to original sources
PubMed1992

Progesterone receptor immunoreactivity in pancreatic endocrine tumors. An immunocytochemical study of 156 neuroendocrine tumors of the pancreas, gastrointestinal and respiratory tracts, and skin.

BACKGROUND: The immunoreactivity for progesterone receptors (PR) of the majority of endocrine cells of the human pancreas has prompted the authors to investigate if PR expression is maintained in pancreatic endocrine tumors and is correlated with the main clinicopathologic features of these neoplasms. Furthermore, the study has been extended to other neuroendocrine cells and tumors to determine whether PR immunoreactivity is a common feature of neuroendocrine cells and tumors other than those of the pancreas. METHODS: One hundred fifty six neuroendocrine tumors of the pancreas, gastrointestinal and respiratory tracts, and skin were immunostained for PR with three different monoclonal antibodies and for estrogen receptors (ER). Additional immunostainings for general neuroendocrine markers and for pancreatic hormones were performed in selected cases. RESULTS: Nuclear immunoreactivity for PR has been documented in the neoplastic cells of 56 (58.33%) of 96 pancreatic endocrine tumors. PR immunoreactivity was not influenced by the sex and age of the patients or the occurrence of a clinical syndrome related to inappropriate hormone secretion. Tumors synthesizing pancreatic polypeptide, glucagon, and insulin expressed PR in higher percentages (80%, 75%, and 66%, respectively) than those producing other pancreatic hormones or those that were not functioning. Irrespective of the functionally different tumor types, PR immunoreactivity showed a significant correlation (P = 0.0003) with the absence of metastases and the lack of tumor invasion of neighboring organs or of large vessels. As opposed to normal and neoplastic islet cells, the neuroendocrine cells and tumors of the gastrointestinal tract, respiratory tract, and skin did not show any PR immunoreactivity, with the single exception of a typical carcinoid tumor of the lung. ER were not identified in any pancreatic or extrapancreatic neuroendocrine cells or tumors. CONCLUSIONS: Nuclear PR are immunocytochemically detectable in most pancreatic endocrine tumors and are correlated significantly to the absence of pathologic evidence for malignancy. Conversely, PR expression has not been found in normal and neoplastic endocrine cells and tumors investigated.

Adenoma, Islet Cell↗
PubMed1992

Cystic islet cell tumors of the pancreas. A clinico-pathological report of two nonfunctioning cases and review of the literature.

Cystic islet cell tumors of the pancreas are extremely rare. The authors report their personal experience with two cases of nonfunctioning cystic endocrine neoplasms. The tumor was diagnosed preoperatively in one case by ultrasonography (US)-guided fine-needle aspiration cytology, while in the other it was identified only in the surgical specimen after a clinical-radiologic diagnosis of pancreatic mucinous cystic tumor. Immunohistochemical assay showed positivity for the generic neuroendocrine markers (neuron specific enolase, or NSE, synaptophysin, and chromogranin A) in both cases and also for glucagon in one case. The neoplasms were resected by distal pancreatectomy with splenectomy and intermediate pancreatectomy respectively. Both patients are alive and recurrence-free 6 mo and 2.5 yr, respectively, after surgery. The authors also review the existing literature, discussing the pathogenesis of such tumors and the imaging techniques and surgical strategies adopted in their management.

Adenoma, Islet Cell↗
PubMed1992

Diagnostic and therapeutic problems in multicentric renal angiomyolipoma.

Multicentric renal angiomyolipoma is a rare form of benign tumor. However, its effective incidence as evaluated in autopsy studies may be as high as 8%. There are 2 main types of renal angiomyolipoma, that is isolated forms and those associated with other diseases, such as phakomatosis, polycystic kidneys and fibromuscular dysplasia. The tumor may also display malignant behavior with local invasiveness and regional lymph node involvement. However, the clinical course is benign and multicentricity is important for prognosis. Histopathological diagnosis often is difficult. Immunohistochemical analysis of surgical specimens using a panel of monoclonal antibodies, including HMB-45 and actin, enabled us to make a definitive diagnosis in 3 cases of multicentric renal angiomyolipoma.

Adolescent↗
PubMed1992

PEC and sugar.

Explore the source record for details and available documents.

Hemangioma↗
PubMed1992

Immunodetection of proliferating cell nuclear antigen assesses the growth fraction and predicts malignancy in endocrine tumors of the pancreas.

Thirty-five endocrine tumors of the pancreas, 17 functioning and 18 nonfunctioning, were immunohistochemically studied for the expression of proliferating cell nuclear antigen (PCNA) using 19A2 and PC10 monoclonal antibodies. The proportion of PCNA-reactive cells (PCNA index) ranged from 0.2 to 27% in functioning tumors and from 0.1% to 55% in nonfunctioning tumors. PCNA index showed a statistically significant correlation with mitotic and Ki67 indexes. The median values of PCNA index identified three groups of patients: group A (PCNA < or = 2%), including 13 functioning and six nonfunctioning tumors; group B (PCNA between 2 and 5%), including three functioning and three nonfunctioning tumors; group C (PCNA > 5%), including one functioning and nine nonfunctioning tumors. All group A tumors were confined to the pancreas. In group B, the functioning tumors were limited to the pancreas, and the nonfunctioning tumors extended to extrapancreatic tissues. All group C patients had extrapancreatic extension of the disease. At follow-up, a PCNA index higher than 5% correlated to a decreased mean survival. Our data suggest that PCNA index is a reliable tool to assess the growth fraction, discern local from advanced diseases, and predict malignancy in pancreatic endocrine tumors.

Adolescent↗
PubMed1991

Evidence of c-myc gene abnormalities in mediastinal large B-cell lymphoma of young adult age.

Six cases of mediastinal large B-cell lymphoma (MLCL) with sclerosis were analyzed for the presence and patterns of c-myc and bcl-2 loci rearrangements, and for the presence of Epstein-Barr virus DNA sequences by Southern blot hybridization, c-myc gene alterations were found in three of six cases. Two cases showed the presence of mutations or small rearrangements at the 3' end of the first exon. The c-myc gene abnormalities found in these two cases are similar to those observed in the translocation 8;14 of the endemic Burkitt's lymphomas or in its variants t(2;8) and t(8;22). A third case showed a major rearrangement of c-myc gene, with truncation within its first intron, similar to those observed in sporadic Burkitt's and in acquired immunodeficiency-associated lymphomas. None of the cases displayed bcl-2 gene rearrangements or contained viral sequences. Our data suggest a possible role for a translocation-mediated c-myc activation in the pathogenesis of MLCL. Conversely, bcl-2 gene and Epstein-Barr virus do not appear to be involved in the pathogenesis of these peculiar lymphomas. The association between c-myc structural modifications and MLCL also seems to be of relevance in light of the peculiar tendency of this tumor to involve unusual extranodal site (eg, kidney), reminiscent of the spreading attitude of Burkitt's limphomas.

Adult↗
PubMed1991

Ultradian and circadian changes in the cAMP concentration in the preoptic region of the rat.

The concentration of adenosine 3',5'-cyclic monophosphate was measured, during the wake-sleep cycle, in the preoptic region and the cerebral cortex of rats kept in normal laboratory conditions (ambient temperature 22 +/- 0.5 degrees C, 12 h:12 h light-dark cycle) and, during wakefulness, in the preoptic region of rats exposed to extended light and dark periods (i.e. dark in the light hours of the normal photoperiod, and light in the dark hours of the normal photoperiod). The results show that the concentration of cAMP in the preoptic region changes according to the ultradian wake-sleep cyclic, decreasing from wakefulness, through synchronized sleep and to desynchronized sleep. This pattern of change was found to occur both in light and dark hours, however, in the dark hours the levels of preoptic cAMP are higher than those observed in the light hours. In contrast, no significant modification in cAMP concentration was found in the cerebral cortex. In the extended light and dark periods preoptic cAMP concentration increases above the levels found during wakefulness in normal photoperiods. These results show that preoptic cAMP concentration is influenced by ultradian and circadian factors which also appear to be related to sleep processes.

Activity Cycles↗
PubMed1991

Gastric carcinoids and their precursor lesions. A histologic and immunohistochemical study of 23 cases.

A histologic and immunohistochemical study was carried out in 23 unselected nonantral gastric carcinoids and their precursor lesions classified according to Solcia et al. None of the patients showed Zollinger-Ellison syndrome. Two variants of carcinoids showing distinctive pathologic and pathogenetic characteristics were identified on the basis of presence or absence of associated chronic atrophic gastritis type A (A-CAG). Chronic atrophic gastritis type A was found in 19 cases showing either single or multiple neoplasms, tumor extension limited to the mucosa or submucosa, consistent endocrine cell precursor changes in extratumoral mucosa, and consistent hypergastrinemia and/or G cell hyperplasia. Associated precursor lesions were only hyperplastic in all but two cases with single carcinoids whereas they were also dysplastic in all but one case with multiple carcinoids. The four tumors arising in nonatrophic mucosa were all single, more aggressive, and not associated with extratumoral endocrine cell proliferations or with signs of gastrin hypersecretion. Tumor cells were diffusely immunoreactive for chromogranin A and synaptophysin but usually negative for chromogranin B or HISL-19. Scattered serotonin cells were found in ten carcinoids. They were more frequent in infiltrating than in intramucosal tumors as were the less represented pancreatic polypeptide cells whereas the reverse was found for alpha-subunit-containing cells. These results are of relevance for tumor pathogenesis and may provide the rationale for a less aggressive therapeutic approach in the patients.

Adolescent↗
PubMed1991

False-positive immunostaining of normal epithelia and carcinomas with ascites fluid preparations of antimelanoma monoclonal antibody HMB45.

HMB45 is a melanoma-specific monoclonal antibody that has found widespread use in diagnostic pathology. Recent reports, however, have suggested that this antibody may cross-react with a small number of carcinomas and other epithelial cells. The authors tested the hypothesis that these latter reports represent examples of false-positive immunostaining by comparing the immunostaining on breast, salivary gland, and lung tumors with the following: (1) a commercial ascites preparation of this monoclonal antibody; (2) a protein A-purified antibody preparation derived from ascites fluid; and (3) supernatant fluid obtained from the hybridoma cell line. The authors found that all examples of nonmelanoma immunostaining in the carcinomas tested were eliminated with the nonascites fluid preparations, whereas strong immunostaining of melanomas was retained. The authors conclude that contaminated commercial ascites fluid preparations of HMB45 may account for most, if not all, of the reports of nonmelanoma immunostaining with HMB45.

Antibodies, Monoclonal↗
PubMed1991

Melanocyte-marker-HMB-45 is regularly expressed in angiomyolipoma of the kidney.

HMB-45 (melanocytic cell-specific monoclonal antibody) immunoreactivity was investigated in 10 cases of angiomyolipoma (AML) (1 with massive regional lymph node involvement) of the kidney and detected in all of them. No HMB-45 immunoreactivity was found in other tumors of the region which can occasionally be confused with AML, such as renal cell carcinoma, Wilms' tumor, and retroperitoneal sarcoma (leiomyosarcoma and liposarcoma). These findings indicate that HMB-45 is not a melanocyte-restricted marker and suggest that its expression might be useful in distinguishing AML from other tumors of the kidney and retroperitoneum.

Antibodies, Monoclonal↗
PubMed1990

The short-term effects of dl-propranolol on the wake-sleep cycle of the rat are related to selective changes in preoptic cyclic AMP concentration.

The short-term effects of the intraperitoneal administration of dl-propranolol on the wake-sleep cycle of the rat were studied in relation to the cyclic AMP concentration in the preoptic region and cerebral cortex. The results show that propranolol, but not saline, affected all stages of the wake-sleep cycle, increasing wakefulness, decreasing synchronized sleep and abolishing desynchronized sleep. These effects were associated with a decrement in cyclic AMP concentration both in wakefulness and synchronized sleep. However, this decrement was relatively larger in the preoptic region than in the cerebral cortex. The effects of the drug on cyclic AMP accumulation were also studied in hypoxia, a condition of unspecific brain stimulation. In this condition, the cyclic AMP concentration in both brain regions was found to be higher than that observed during either wakefulness or synchronized sleep. In the hypoxic condition propranolol was found to decrease the nucleotide concentration to the same levels observed in wakefulness and synchronized sleep following its administration. However, no difference in the relative magnitude of the decrement was found between the preoptic region and the cerebral cortex. These findings suggest that in both brain regions the drug acts on a cyclic AMP accumulating system, which may be defined as propranolol-sensitive. The activity of the propranolol-sensitive system in the preoptic region would appear to be related to wake-sleep processes.

Animals↗
PubMed1990

Expression and gene rearrangement of the T-cell receptor in human thymomas.

Human thymomas are epithelial neoplasms frequently associated with an exuberant lymphoid component. This mixture of epithelial cells and lymphocytes closely mimicks the organization of normal thymic cortex. However, it is not known whether thymocytes in thymoma express the T-cell receptor (TCR) for the antigen. We have analyzed the molecular configuration of TCR genes and their phenotypic expression in eight thymomas. In all we detected polyclonal rearrangements of TCR genes and cytoplasmic expression of TCR molecules in most thymocytes, thus indicating that rearranged TCR genes in thymomas are functioning genes. In addition, these findings suggest that the epithelial component of thymomas, even if neoplastic, is still capable of directing thymocyte differentiation.

Adolescent↗
PubMed1990

Peripheral giant cell granuloma: evidence for osteoclastic differentiation.

Nine cases of peripheral giant cell granuloma of the oral cavity have been immunohistochemically analyzed to assess the nature of the giant cells. Giant cells were unreactive when tested with antibodies recognizing myelomonocytic and macrophage markers (lysozyme, MAC 387, HAM 56) but showed strong immunoreactivity with MB1, an antibody reactive with osteoclasts. It is concluded that giant cells characterizing giant cell granuloma exhibit a phenotype distinct from other giant cells found in sites of chronic inflammation and may be true osteoclasts.

Antibodies, Monoclonal↗