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M Bonato

Publications and source records attributed to M Bonato.

At least 19 recordsLinked to original sources
PubMed2003

A cell-based approach for the early assessment of the phospholipidogenic potential in pharmaceutical research and drug development.

Phospholipidosis is a term commonly used to indicate a phospholipid storage disorder; in affected cells, phospholipids accumulate in lysosomes that acquire a multilamellar morphological appearance. Cationic amphiphilic drugs (CADs) are suggested to induce phospholipidosis by direct interaction of xenobiotics with intracellular phospholipids or by the action of xenobiotics on the synthesis and metabolism of phospholipids. To date, electron microscopy (EM) represents the most reliable and the preferred method for the demonstration of phospholipidotic cell damage. Nevertheless, EM has a low throughput, it is expensive, and it is not suitable for screening purposes. We discuss here the assessment of the the phospholipidogenic potential of drugs using a cell culture-based model. In this test, intracellular phospholipids of treated U-937 cells (a human monocyte-derived cell line) were measured using the fluorescent probe Nile red. Eleven CADs reported to induce phospholipidosis in vivo and eight nonphospholipidogenic drugs were tested. Results obtained with the U-937 model confirmed the phospholipidogenic potential of drugs tested as described in the literature. Results have also been correlated with data obtained with a physical-chemical model (chromatographic hydrophobicity index measurement). Good correlation was obtained, confirming that the physical-chemical properties of CADs play a crucial role in the development of phospholipidosis. This work demonstrates that the U-937 model is a rapid and sensitive method for the determination of phospholipidosis-mediated cell damage. The specificity and the predictive potency observed make this method suitable for screening purposes in pharmaceutical development.

Cations↗
PubMed2001

Nodal marginal zone B-cell lymphomas may arise from different subsets of marginal zone B lymphocytes.

Nodal marginal zone B-cell lymphoma (MZL) is a rare and not extensively studied entity that accounts for approximately 2% of all non-Hodgkin lymphomas. Complementarity-determining regions 2 and 3 (CDR2, CDR3) of the immunoglobulin heavy-chain variable region (V(H)) genes were amplified by polymerase chain reaction (PCR), cloned, and sequenced in 8 patients with nodal MZL. All showed a potentially functional V(H) rearrangement. The use of V(H) gene families was unbiased and without overrepresentation of any particular V(H) gene or gene family. The presence of somatic V(H) mutations was detected, with a deviation from the closest germ line sequence ranging from 4% to 17% in 6 of 8 patients. In 3 mutations, the replacement-to-silent mutation ratio suggested the presence of an antigen-selected process. Sequencing different subclones of the same cloned PCR products allowed the detection of intraclonal variability in 4 analyzed patients. The observed pattern of V(H) mutations suggested that nodal MZL, formerly deemed a malignancy of memory B cells, may arise from different subsets of marginal zone B cells-the naive B cells that express unmutated V(H) genes-from memory B cells showing somatic mutations without intraclonal variation, and from germinal center B cells defined by their capacity to undergo the somatic hypermutation process. (Blood. 2001;98:781-786)

Adult↗
PubMed2001

In vitro bone marrow granulocyte-macrophage progenitor cultures in the assessment of hematotoxic potential of the new drugs.

In pharmaceutical research, in vitro toxicity tests, for assessing the potential toxicity of new chemical entities are necessary in the early stages of the developmental process, when no information is available about the metabolism or even the target organ toxicity of the compounds to be tested. In vitro specific organ toxicity tests, such as the granulocyte-macrophage colony-forming unit (CFU-GM) clonogenic assay, are useful tools for predicting the adverse effects of new compounds on the blood-forming system, provided that some reference points are available, e.g., toxicological information about compounds belonging to the same chemical class and structure-activity relationship data. Furthermore, when no information is available about metabolism, the in vitro system should cover as many possibilities as possible, to avoid false positive or false negative results. In fact, while many compounds are metabolized to a variety of inactive chemical species, some undergo bioactivation to form more active metabolites. The addition of a metabolic activation system to the CFU-GM assay enables assessment of direct and metabolism-mediated toxicity. The regulatory agencies and industry value the concept of assays performed with and without metabolic activation, since they often have to take decisions about compounds with unknown mechanisms of action. CFU-GM assay, designed in this way, is an example of such a mechanism-naive assay. It has been suggested that, for new compounds, metabolites should be generated and tested both in the presence and in the absence of the parent compound itself, to identify the possible contribution of metabolites to the hematotoxicity observed, and to determine whether there is any synergistic or antagonistic effect between metabolites and the parent compound that might affect hematotoxicity in vivo. Various approaches can be used to obtain such information.

Animals↗
PubMed2001

Deep tissue biopsy vs. superficial swab culture monitoring in the microbiological assessment of limb-threatening diabetic foot infection.

AIMS: The results of ulcer swabbing vs. deep tissue biopsy have been compared prospectively in 29 diabetic patients with limb-threatening foot infection, to investigate the effectiveness and reliability of each method, and to evaluate whether any of the two could be more suitable for the microbiological follow-up of severe lesions. METHODS: Microbiological samples were collected by using both methods at fixed intervals after therapy commencement (i.e. at day 0, 7, 14, and 30). Statistical comparison was performed between the results of each sampling procedure after the end of follow-up. RESULTS: At enrolment, the mean number of isolates per patient was 2.34 by swabbing and 2.07 by tissue biopsy sampling; the rate of isolation for anaerobes with the two methods was 35% and 25%, respectively; no statistical differences could be observed between the two procedures in terms of either species or frequency of isolation. Anaerobic species were never detected after the first 2 weeks of appropriate treatment, and those ulcers which were still active at day 30 yielded almost exclusively Gram-positive bacteria. At the end of follow-up, deep tissue cultures appeared to exhibit a higher diagnostic sensitivity with respect to swabs. CONCLUSIONS: Swabbing and deep tissue cultures appear to be equally reliable for the initial monitoring of antimicrobial treatment in severe diabetic foot infection. However, our experience seems to suggest that deep tissue might be more sensitive than swabbing for monitoring those isolates that have been selected for antibiotic resistance, i.e. those from ulcers that are still active after 30 days of treatment.

Adult↗
PubMed2000

[Primary gastric lymphomas. Clinico-pathological study and evaluation of prognostic factors in 65 cases treated surgically].

Based on the histological criteria proposed by the REAL and adopted by the WHO Classification, 30 cases of MALT type lymphoma, 18 cases of diffuse large B cell lymphoma (DLCL), and 17 cases of DLCLs, associated with a MALT type, were identified in a series of 65 surgically treated primary gastric lymphomas. The clinical records of the patients were analyzed retrospectively and the resected specimens were immunostained for bcl-2, p53 and Ki-67. Primary gastric DLBCLs, with or without a MALT type component, disclosed a higher stage of local extension, a more frequent nodal involvement and a significantly worse survival than pure MALT types. High p53 expression and high proliferation rate correlated with the presence of a large cell component and appeared useful for its identification in mixed forms. Low bcl-2 expression discriminated DLCL from DLCL/MALT. Tumor size, stage and Mib-1 index revealed a value in predicting prognosis.

Adult↗
PubMed1999

Microsatellite instability in gastric MALT lymphomas and other associated neoplasms.

BACKGROUND: Microsatellite instability (MSI), caused by a reduced efficacy of the DNA mismatch repair (MMR) machinery, represents a type of genomic instability frequently detected in HNPCC spectrum cancers and in a subset of sporadic carcinomas. The involvement of MSI in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) has never been conclusively investigated. In this study, we tested the presence of MSI in tumor samples of patients harboring both MALT lymphomas and other types of malignancies. MATERIALS AND METHODS: We examined 10 microsatellite loci (D3S11, D3S1261, D3S1265, D6S262, D6S193, BAT-26, BAT-25, D17S250, APC, D2S123) out of a total of 34 primary tumors from 14 patients with MALT lymphomas and one or more additional neoplasms. The patients' MSI results were also tested for an association with a positive family history of cancer. RESULTS: MSI, defined by the presence of microsatellite alterations in more than 40% of the examined loci, was scored negative in all tumors studied, and pedigree analysis failed to identify any condition of familial cancer among the patients examined. CONCLUSIONS: The present study suggests that defects in DNA mismatch repair do not contribute significantly to the molecular pathogenesis of MALT lymphomas and associated neoplasms.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1998

Lymph node histology in typical and atypical chronic lymphocytic leukemia.

According to the French-American-British (FAB) proposal on the classification of chronic lymphoid leukemia (CLL), the disorder can be subdivided into typical and atypical CLL. We recently demonstrated the prognostic significance of this subgrouping and based on these results we suggested that typical and atypical CLL represent two closely related, but different entities. These results prompted us to investigate 42 patients diagnosed with CLL based on the results of lymph node biopsy in order to identify the histologic counterpart of the CLL variants. A first group of 14 cases showed a monomorphic proliferation of small round lymphocytes associated with the occurrence of small pseudofollicles. All these cases were diagnosed as typical CLL on peripheral blood (13 cases) or bone marrow smear (1 case). The remaining 28 cases showed aberrant histologic features characterized by the presence of large numbers of paraimmunoblasts and prolymphocytes, forming very large pseudofollicles, and/or by nuclear irregularities of the neoplastic cells. Based on peripheral blood smears (22 cases) or bone marrow smears (six cases), two cases showed no peripheral blood involvement, 21 cases were diagnosed as atypical CLL, and five as typical CLL. From these data we can conclude that a histologic counterpart of the CLL variants recognized in the FAB proposal does exist; moreover, our data may explain reports on lymph node involvement by CLL composed of small cleaved cells and clarify the occurrence of pseudofollicles in cases described as mantle cell lymphomas.

Adult↗
PubMed1998

Ki-ras and p53 gene mutations in pancreatic ductal carcinoma: a relationship with tumor phenotype and survival.

We investigated a series of clinically well documented pancreatic ductal adenocarcinomas for the presence of molecular alterations of the p53 and Ki-ras genes and their correlations with p53 nuclear immunohistochemical expression. The results were evaluated in comparison with cellular expression, by ductal cancer cells, of gastric (PGII) and intestinal (CAR-5) antigens and with several clinicopathologic parameters such as grade, stage, size and lymph-node status. Ki-ras gene mutation at codon 12 was detected in 77.7% of cases with no relationship with tumor grade, stage, and survival of the patients. p53 gene mutations were found in 18/31 (58%) cases and p53 immunohistochemical overexpression was detected in 51/104 (49%) of cases. Both Ki-ras and p53 gene mutations were found in 13/31 (41.9%) of adenocarcinomas examined, while Ki-ras and p53 overexpression was detected in 19/45 (42.2%). A positive correlation between p53 overexpression and tumour grade was found (p0.0001) but no relationship was found between p53 overexpression, tumor stage, lymph-node status and size of the tumors. A trend toward an association of p53 overexpression with poorer survival was found in patients with pancreatic cancers of the same grade, stage or with the same immunophenotype, but the data did not reach statistical significance. The expression of gastric and intestinal antigenic markers in pancreatic adenocarcinomas and the presence of molecular abnormalities analogous to those found in gastric and colorectal cancers suggest common genetic pathways in gastrointestinal and pancreatic carcinogenesis.

Adult↗
PubMed1997

Pathology of disappearing bone disease: a case report with immunohistochemical study.

A case of disappearing bone disease of the proximal femur is reported with histopathological and immunohistochemical studies. There was a densely packed cellular tissue, positive to endothelial antibodies, in areas of massive bone destruction. A more differentiated vascular tissue was present where trabecular cancellous or cortical bone was preserved with only focal zones of accelerated bone remodelling. The self-limited course correlates well with two phases of evolution of the histopathological lesions with neoplastic-like proliferation of endothelial cells corresponding to the rapid and massive bone destruction, and a later differentiation of the cells in mature vascular structures, but still with accelerated bone resorption which is partly compensated by appositional activity.

Arthroplasty, Replacement, Hip↗
PubMed1995

Well-differentiated endocrine tumours of the middle ear and of the hindgut have immunocytochemical and ultrastructural features in common.

The immunocytochemical analysis of two cases of well-differentiated endocrine tumours (carcinoids) of the middle ear revealed predominant cell populations producing pancreatic polypeptide (PP)-related peptides, glucagon-related peptides, and serotonin (the latter only in one case). In consecutive sections PP- and glucagon-related immunoreactivities mainly colocalized in the same tumour cells. Ultrastructurally tumour cells were characterized by medium-sized to large granules of moderate to high density, on which PP and glicentin were localized by the immunogold technique. No amphicrine cells were found. These features are consistent with those of similar tumours in the rectal mucosa that are mainly composed of L cells coexpressing both PP-related and glucagon-related peptides. Additional tumour antigens of hindgut type detected immunohistochemically were prostatic acid phosphatase and CAR-5 mucin. Expression of the CAR-5 antigen was also found in samples of normal middle ear mucosa, in which endocrine cells have not been identified. In case 1 peritumoral mucosal invaginations showed a proliferation of endocrine cells identical immunophenotypically to tumour cells, possibly representing a precursor lesion. It is concluded that well-differentiated endocrine tumours of the middle ear are a distinct pathological entity characterized by multiple hormone production, typically involving three classes of hormones (pancreatic polypeptide-related peptides, glucagon-related peptides, and serotonin) of the hindgut endocrine system.

Adult↗
PubMed1994

K-ras and p53 gene mutations in pancreatic cancer: ductal and nonductal tumors progress through different genetic lesions.

We studied K-ras and p53 gene mutations in a panel of 57 primary pancreatic cancers including ductal and nonductal tumors. DNAs were obtained from formalin-fixed, paraffin-embedded material. Target sequences were amplified by polymerase chain reaction and analyzed by denaturing gradient gel electrophoresis and sequencing. Both K-ras and p53 genes were frequently mutated in ductal cancers (25 of 35, 71.4%; 18 of 35, 51.4%, respectively). K-ras mutations were confined to the second position of codon 12 where base transitions and transversions were equally observed. p53 changes were mainly missense mutations. Transitions and transversions were found equally with a prevalence of G:C-->A:T changes among transitions. No gene alterations were present in the 6 exocrine nonductal tumors and (with one exception) in the 12 endocrine tumors analyzed. Our results indicate that mutated K-ras and p53 genes can cooperate in the establishment of ductal pancreatic cancers, whereas other genetic events have to be present in nonductal tumors. Moreover, K-ras alterations may represent an early event in ductal tumorigenesis, as suggested both by the high gene mutation frequency and by the presence of mutations in low-grade tumors. On the contrary, p53 gene changes seem to represent an event required for the malignancy progression of ductal tumors from lower to higher grades.

Carcinoma, Ductal, Breast↗
PubMed1994

Intraductal papillary-mucinous tumours represent a distinct group of pancreatic neoplasms: an investigation of tumour cell differentiation and K-ras, p53 and c-erbB-2 abnormalities in 26 patients.

Intraductal papillary growth of mucin producing hypersecreting, columnar cells characterizes a group of rare pancreatic exocrine neoplasms which we propose to call intraductal papillary-mucinous tumors (IPMT). We analysed the histopathology of 26 IPMT in relation to gastro-enteropancreatic marker expression, genetic changes and biology. Four IPMT showing only mild dysplasia were considered to be adenomas. Nine tumours displayed moderate dysplasia and were regarded as borderline. Severe dysplasia-carcinoma in situ changes were found in 13 IPMT which were therefore classified as intraductal carcinomas. Six of these carcinomas were frankly invasive and two of these had lymph node metastases. The invasive component resembled mucinous non-cystic carcinoma in all but one tumour which showed a ductal invasion pattern. Immunohistochemically, an intestinal marker type was found in most carcinomas, while gastric type differentiation prevailed among adenomas or borderline tumours. K-ras mutations (seven at codon 12 and one at codon 13) were found in 31% of IPMT (2 adenomas, 1 borderline, 5 carcinomas). Nuclear p53 overexpression was detected in 31% of IPMT (6 carcinomas and 2 borderline IPMT) and correlated with p53 mutations (one at exon 8 and the other at exon 5) in two carcinomas. p53 abnormalities were unrelated to K-ras mutation. c-erbB-2 overexpression was observed in 65% of IPMT, with various grades of dysplasia. Twenty-two of 24 patients are alive and well after a mean post-operative follow-up of 41 months. Only two patients, both with invasive cancer at the time of surgery, died of tumour disease. It is concluded that pancreatic IPMT encompass neoplasms which, in general, have a favorable prognosis, but are heterogeneous in regard to grade of dysplasia and marker expression. Adenoma, borderline tumour, intraductal carcinoma and invasive carcinoma can be differentiated. p53 changes but not K-ras mutation or c-erbB-2 overexpression are related to the grade of malignancy. Most IPMT differ in histological structure, marker expression and behaviour from ductal adenocarcinoma.

Adult↗
PubMed1992

Differential diagnostic patterns of lung neuroendocrine tumours. A clinico-pathological and immunohistochemical study of 122 cases.

A series of 3 tumourlets (TLs), 81 typical carcinoids (TCs), 14 atypical carcinoids (ACs) (well-differentiated neuroendocrine carcinomas, WDNCs) and 24 small cell-intermediate cell carcinomas (SCC-ICCs) of the lung were studied. Histopathological features were correlated with amine and peptide hormone immunoreactivity and with clinical data. All types of tumours expressed general neuroendocrine (NE) markers: Grimelius positivity and chromogranins were detected more frequently in well-differentiated (TLs, TCs) than in less well differentiated tumours [ACs (WDNCs) and SCC-ICCs] whereas neuron specific enolase (NSE) was prominent in the latter tumours. TLs and peripheral TCs were benign, often showing a paraganglioid pattern and frequently expressing gastrin-releasing peptide (GRP), which is present in the peripheral airways of normal lung. Central TCs were associated with lymph node metastases in 8.5% of the cases, frequently had a trabecular architecture, often associated with human milk fat globule 2 (HMFG2)-positive acinar and rosette-like structures, and were mainly immunostained for the alpha-subunit of human chorionic gonadotrophin (alpha-hCG) and serotonin. ACs (WDNCs) were associated with intrathoracic and/or extrathoracic metastases in 57.1% of the cases with a mortality rate of 35.7%. Their histological and cytological features were intermediate between those of TCs and SCC-ICCs. ACs (WDNCs) expressed serotonin and alpha-hCG less frequently than TCs. All SCC-ICCs were surgically treated and displayed a mortality rate of 91.6% with a mean survival of 10.2 months after operation. These tumours were characterized by high expression of HMFG2 and NSE, while the expression of both orthotopic (serotonin, GRP) and ectopic (ACTH) specific NE substances was very low. Since all TCs (either central or peripheral) had a favourable outcome, while about 36% of ACs (WDNCs) were fatal, the latter seem more appropriately designated "well-differentiated NE carcinomas". The differential diagnosis between different NE tumours of the lung is important and is mainly based on morphology. Both panendocrine and specific immunohistochemical markers are helpful in distinguishing the less aggressive, mostly benign varieties from the more malignant varieties.

Adult↗
PubMed1990

Ductal cancers of the pancreas frequently express markers of gastrointestinal epithelial cells.

It has been found by immunohistochemical staining that antigens normally found in gastric and/or intestinal epithelial cells are expressed in most differentiated duct cell carcinomas of the pancreas. Among 88 such tumors, 93% and 92%, respectively, expressed M1 and cathepsin E, markers of gastric surface-foveolar epithelial cells, 51% expressed pepsinogen II, a marker of gastroduodenal mucopeptic cells, 48% expressed CAR-5, a marker of colorectal epithelial cells, and 35% expressed M3SI, a marker of small intestinal goblet cells. Most of the tumors also expressed normal pancreatic duct antigens; 97% expressed DU-PAN-2, and 59% expressed N-terminus gastrin-releasing peptide. In agreement with these findings, electron microscopy revealed malignant cells with fine structural features of gastric foveolar cells, gastric mucopeptic cells, intestinal goblet cells, intestinal columnar cells, pancreatic duct epithelial cells, and cells with features of more than one cell type. Normal pancreatic duct epithelium did not express any marker of gastrointestinal epithelial cells, whereas such benign lesions as mucinous cell hypertrophy and papillary hyperplasia commonly expressed gut-type antigens but rarely expressed pancreatic duct cell markers. By contrast, lesions characterized by atypical papillary hyperplasia commonly expressed both gastric and pancreatic duct cell markers. Metaplastic pyloric-type glands expressed pepsinogen II and, except for their expression of cathepsin E, were indistinguishable from normal pyloric glands. In marked contrast, the immunohistochemical and ultrastructural features of 14 ductuloacinar cell tumors were those of cells lining terminal ductules, centroacinar cells, and/or acinar cells; none expressed any gut-type antigen. The results indicate that gastrointestinal differentiation is common in both benign and malignant lesions of pancreatic duct epithelium and suggest that duct cell carcinomas are histogenetically related to gastric- and intestinal-type metaplastic changes of epithelial cells lining the main and interlobular ducts of the pancreas.

Antibodies, Monoclonal↗
PubMed1989

[Brown tumor of the upper jaw. Surgical-rehabilitation problems].

The Authors describe etiology, pathogenesis and main clinical aspects of brown tumors in patients with chronic renal failure. Then, by presenting two cases of patients with secondary hyperparathyroidism and brown tumors of upper maxillary bone, they report the measures to be applied for the surgical treatment and prosthetic management of these patients. In both cases the patients have been undergone a radical resection of a brown tumor of the palate. After maxillectomy have been successfully applied at first an interim obturator prosthesis and then, approximately three months later the definitive obturator prosthesis.

Adult↗
PubMed1989

Free perforation due to colonic adenocarcinoma in Crohn's disease.

Free perforation of the bowel due to cancer in Crohn's disease is very rare. One case found among 75 cases of Crohn's disease is reported. The perforation occurred in a mucinous adenocarcinoma of the ascending colon in a 54-year-old woman with a 17-year history of Crohn's disease, who had undergone two previous operations of small bowel and colonic resection. A right hemicolectomy was performed; the patient had an uneventful recovery and does not show recurrence of cancer at 31-month follow-up. This is in contrast with a recent review, in which a very poor prognosis was claimed for the perforated colonic cancer in Crohn's disease.

Adenocarcinoma, Mucinous↗
PubMed1989

Mediastinal malignant carcinoid with Cushing's syndrome: immunohistochemical and ultrastructural study.

A case of thymic atypical carcinoid with Cushing's syndrome and unfavorable clinical course is reported. Immunohistochemical analysis reveals distinct staining of tumor cells for ACTH, neuron-specific enolase, chromogranins (CG) and S-100 protein and with PHE-5 monoclonal antibody. At an ultrastructural level, the cells are undifferentiated with only a few neurosecretory granules. In the present case, immunohistochemical stainings for CG and with PHE-5 antibody seem reliable diagnostic tools, easily demonstrating the neuroendocrine nature of the neoplasm. NSE immunoreactivity can be an additional criterion. S-100-positive cells, which are present throughout the tumor, recall 'sustentacular cells', described in other neuroendocrine tumors.

Adrenocorticotropic Hormone↗