Search PubMed⌕ Search

Biomedical subjects

M Nuti

Publications and source records attributed to M Nuti.

At least 37 records · Page 2Linked to original sources
PubMed1989

A monoclonal antibody (D612) with selective reactivity for malignant and normal gastro-intestinal epithelium.

We describe the generation and characterization of a monoclonal antibody (MAb), designated D612, with selective reactivity for malignant and normal gastro-intestinal epithelium. MAb D612, a murine IgG2a, was generated using a membrane-enriched fraction of a human colon carcinoma biopsy as immunogen. Employing radioimmunoassays (RIAs) of biopsy extracts to a range of normal and neoplastic tissues, and both immunofluorescence and immunoperoxidase assays on frozen sections of a range of normal and neoplastic tissues, we have shown that MAb D612 binds to 82% of colorectal carcinomas tested (n = 67) and to normal gastro-intestinal epithelium, but does not bind similarly to either neoplastic or normal tissues from a wide range of other sites. Western blotting has shown MAb D612 to react with a high-molecular-weight antigen. Live cell RIAs and FACS analyses demonstrate the reactive epitope to be present on the surface of colon carcinoma cells. Immunohistochemical studies have shown intense membrane staining of colon adenocarcinomas with MAb D612; the vast majority of both primary and metastatic colon adenocarcinomas from a variety of sites were positive with many lesions showing homogeneous staining of virtually all cells present. Using human effector cells, we also showed that MAb D612 mediates antibody-dependent cell-mediated cytotoxicity (ADCC) of human colon carcinoma cells; this activity was enhanced in the presence of interleukin (IL-2). Radiolabelled D612-purified IgG selectively binds a human colon carcinoma xenograft in situ. The pattern of membrane-associated staining, the molecular weight of the reactive antigen, the IgG2a isotype, the ability to mediate ADCC in the presence of IL-2, and the immunohistochemical and RIA studies demonstrating highly restricted reactivity to malignant and normal gastro-intestinal tissue, all distinguish MAb D612 from other MAbs thus far described.

Adenocarcinoma↗
PubMed1989

[Antibodies against Hantaan virus and Leptospira in subjects at risk in Rome].

A survey on the prevalence of Hantaan and leptospiral antibodies on mammalogists and rodent control personnel was performed. None of the 66 trappers studied (using IFI ) had detectable Hantaan antibody, while only 2 out of 20 mammalogists presented antibody at low titer (1:32). For leptospiral antibody the microagglutination test (MAT) using live leptospires as antigen was performed. 14 out of 66 trappers, or 21.2 per cent, had antibodies, at titer of 1:50 or more, to various leptospiral serovars: L.icterohaemorrhagiae in 12 cases, L.hardjo in 1 case, L.bratislava in 1 case. On the contrary, none of the mammalogists showed positivity for any of 16 serovars used. The environmental risk factors could justify the high prevalence of leptospiral antibodies in the field workers (trappers), while continuous laboratory contacts with rodents explain the presence of Hantaan virus antibodies in mammalogists .

Agglutination Tests↗
PubMed1987

Mammary cancer antigen recognized by monoclonal antibody B72.3 in apocrine metaplasia of the human breast.

Monoclonal antibody B72.3 recognizing a pan-associated carcinoma antigen expressed also in metastatic human breast cancer cells has been tested using the avidin-biotin peroxidase method applied to paraffin-embedded sections in 50 samples of mammary tissue showing apocrine metaplasia and in 58 cases of other mild or severe focal epithelial proliferative changes of the breast, including mostly in situ lobular or ductal carcinomas collateral to clinical cancer removed after radical mastectomy. The antigen detected by this antibody was present in the apocrine cells of 48 cases (96%). In the majority of these cases the reactivity was localized on the luminal border of the apocrine cells and in the luminal secretion. But ten cases showed positive staining also in the cell cytoplasm either focal or diffuse. The normal structures and mild focal hyperplastic changes collateral to clinical cancer were, in the majority of the cases (43 of 55), negative, and, when positive, displayed positivity only at the luminal border. By contrast, the independent foci of in situ carcinoma (17 of 31 examined), the intraduct papillomas (seven cases of 14), and the intraductal component of breast carcinoma (seven cases of 17) were positive, displaying a cytoplasmic focal or diffuse staining. In conclusion, mammary apocrine metaplasia, a metaplastic change of the normal epithelium that has been associated with increased breast cancer risk, shares antigens in common with breast cancer cells and/or with cells showing severe atypia. The possible clinical significance of the site of antigenic expression (cytoplasm or luminal border) needs further investigation.

Antibodies, Monoclonal↗
PubMed1987

High frequency production of hybridomas secreting antibodies to cell antigens.

The efficiency of various immunization protocols for the production of hybridomas secreting immunoglobulins specific to cell antigens was evaluated in 15 different fusion experiments. Some of these experiments were performed with splenic B-lymphocytes from mice at different stages of immunization. This approach allowed a dynamic analysis of immunocompetent splenic B-lymphocyte production during the immunization cycle.

Animals↗
PubMed1986

Use of monoclonal antibodies to human breast-tumor-associated antigens in fine-needle aspirate cytology.

Fine-needle aspiration cytology (FNAC) is currently used in evaluating the nature of breast nodules. In the present study we have examined whether monoclonal antibodies (MAbs) to breast-tumor-associated antigens (BTAA) can be employed in FNAC for the diagnosis of breast cancer. For this purpose we have used 2 murine MAbs recognizing 2 distinct BTAA expressed by breast tumors, irrespective of their histotype, in an indirect avidin-biotin immunohistochemical technique on aspirate smears. The results of this study show that, while benign lesions are consistently negative, tumor cells containing aspirates are reactive with at least one MAb in 95% of the cases. Thus, selected MAbs to BTAA may be a powerful diagnostic tool in conjunction with conventional cytology, and because of the objective interpretation of the immunohistochemical findings, FNAC of the breast can eventually be extended outside specialized institutions.

Adult↗
PubMed1985

Comparison of sensory and pain threshold in tooth pulp stimulation in normotensive man and essential hypertension.

Recent studies indicate a diminished responsiveness to noxious stimuli in arterial hypertension in the experimental animal. A similar finding is also reported in the only study published to our knowledge on this subject in man. The aim of the study was to assess in humans the sensory and pain threshold by a non-invasive tooth pulp stimulation test (stepwise increased electrical stimuli delivered by a commercial pulp tester). Subjects had to report when they started to feel pulp stimulation and when this became painful. The data reported are the means of the measurements on four healthy teeth in each subject. Significantly higher values (expressed as relative units [RU]) were found in 28 non-treated essential hypertensives compared with 33 normotensive controls for sensory threshold (40.64 +/- 8.07 versus 29.96 +/- 6.82 RU, P < 0.0001) and for pain threshold (55.67 +/- 12.74 versus 42.08 +/- 12.58 RU, P < 0.001). Multivariate analysis of variance showed that this difference was apparently not related to age and sex. These data lend further support to the view that pain modulation may be altered in the hypertensive state in man.

Adolescent↗
PubMed1984

Morphologic assessment of reactivity to monoclonal antibodies generated against breast cancer cells in mammary tissues removed for clinical dysplasia or cancer.

Monoclonal antibodies B 6.2, B 72.3 and B 1.1, reactive against tumor-associated antigens of human breast cancer, have been tested on histologic sections of paraffin blocks from 49 cases of breast cancer and from 13 cases of mammary dysplasia. The results have shown that: (a) the three monoclonal antibodies recognize different antigenic determinants of the cancer cells; (b) monoclonal antibodies B 6.2 and B 1.1 recognize antigens which are frequently expressed in cancer cells; (c) the antigen recognized by monoclonal antibody B 72.3, at the concentrations used, is less frequently expressed in tumors, while it seems to be selective for the apical cell border and luminal secretions of apocrine metaplastic lobules or cysts occurring in mammary dysplasia; (d) intracytoplasmic expression of the antigens is observed only in cancer cells, with rare exceptions; (e) tumor cell populations are heterogeneous in respect to the expression of the antigens detected by the monoclonal antibodies tested; (f) the antigens detected are unrelated to the tumor histotype; (g) the frequency of axillary lymph nodal metastases is not influenced by the presence or intensity of antigenic expression in the primary tumors; but (h) in metastatic tumor cell populations the antigenic expression is higher than in primary tumors. This fact suggests some relationship between tumor metastatization and the expression of antigens recognized by the monoclonal antibodies tested.

Adult↗
PubMed1983

Differential binding to human mammary and nonmammary tumors of monoclonal antibodies reactive with carcinoembryonic antigen.

Splenic lymphocytes of mice immunized with membrane enriched fractions of human mammary carcinomas were fused with the NS-1 nonsecretory++ myeloma cell line. The resulting hybridomas were screened for the synthesis of immunoglobulins reactive with human mammary tumor associated antigens, and two IgG monoclonal antibodies (B1.1 and F5.5) were identified as being reactive with purified carcinoembryonic antigen (CEA). These antibodies were shown to bind to different epitopes on CEA based on their differential reactivities to five different purified CEA preparations, and their differential binding to the surface of tumor cells derived from various organ sites. Monoclonal B1.1 bound equally to the surface of human breast, colon, and melanoma cell lines. Monoclonal F5.5, on the other hand, did not react with the surface of melanoma cell lines, and showed a differential binding to breast carcinoma versus colon carcinoma cells. Monoclonals F5.5 and B1.1 were both used in immunoperoxidase studies with fixed tissue sections of a variety of histologic types of human mammary carcinomas and were shown to be reactive with 55% and 66%, respectively, of tumor masses.

Antibodies, Monoclonal↗
PubMed1983

Definition of antigenic heterogeneity and modulation among human mammary carcinoma cell populations using monoclonal antibodies to tumor-associated antigens.

Murine monoclonal antibodies, prepared against human metastatic mammary tumor cells, were used to demonstrate differential expression of several tumor-associated antigens (TAAs) among various mammary carcinomas and within a given tumor mass. Using the immunoperoxidase technique on serial sections of 39 human primary mammary carcinomas, a spectrum of antigenic phenotypes of TAAs was observed: 13% of the tumors reacted with all of a panel of four monoclonal antibodies; while 10% of the mammary tumors scored negative with all four antibodies. The remaining 30 tumors could be divided into several additional groups based on their differential reactivity with some, but not all, of the monoclonal antibodies. Furthermore, variation among mammary carcinomas was also observed in the cellular localization of antigens. Antigenic phenotypic diversity of mammary tumor cell populations within a given tumor mass was also observed; this was noted with respect to (a) antigenic expression in one area of a tumor mass and not another and (b) a "patchwork" effect in which antigens were expressed on cells immediately adjacent to cells which scored negative. Antigenic phenotypic diversity was also observed in established mammary tumor cell lines grown in vitro. A differential loss of some cell surface TAAs was observed as a function of continued cell passage; consistent with this finding, MCF-7 mammary tumor cell lines obtained from four sources could be differentiated from each other by their pattern of cell surface TAA expression. Single-cell clones derived from the MCF-7 mammary tumor cell line exhibited at least four distinct antigenic phenotypes; a change in cell surface phenotype of some of the clones was seen during subsequent passage. This definition of phenotypic variation and modulation of TAA expression among, and within, human mammary carcinomas has implications towards both the design and the outcome of studies involving the in situ immunodetection and therapy of breast cancer.

Adenocarcinoma↗
PubMed1982

A monoclonal antibody (B72.3) defines patterns of distribution of a novel tumor-associated antigen in human mammary carcinoma cell populations.

We report here both the range and patterns of reactivity of an IgG1 monoclonal antibody, B72.3, prepared against human, metastatic mammary carcinoma cells. When the avidin-biotin complex (ABC) immunoperoxidase technique was used on tissue sections, monoclonal B72.3 reacted with 19 of 41 (46%) primary mammary carcinomas and 13 of 21 (62%) metastatic lesions, either in axillary lymph nodes or at distal sites. Variable concentrations of antigen, recognized by B72.3, were observed among mammary tumors, as well as among different cell populations of a given tumor mass. Several patterns of antigen distribution were observed: membrane, diffuse cytoplasmic, focal and marginal. No reactivity was observed to normal mammary epithelium, stroma, or lymphocytes of the breast, nor to any cell types in a variety of other normal human tissues, melanomas, and sarcomas. Reactivity with all of four colon carcinomas was also observed. Assay of serial sections of mammary carcinomas with B72.3 and a monoclonal antibody directed against carcinoembryonic antigen demonstrated that these antigens were both distinct and non-coordinately expressed.

Antibodies, Monoclonal↗
PubMed1982

Human leptospirosis in Somalia: a serological survey.

Sera from Somalis of both sexes between the ages of 16 and 60 were examined for leptospiral agglutinins. 37% of 105 apparently healthy individuals living in the arid Mogadishu area were positive, as were 64% of 107 schistosomiasis patients living in two villages on the Shabeele River (50.5% over-all). Pools of sera from similar subjects, as well as leprosy patients living on the Juba River and patients in Mogadishu hospitals with suspected viral hepatitis showed a similar prevalence rate of 56%. These figures are higher than prevelance rates for leptospiral antibodies generally found in other parts of the world, and in part may be related to the nomadic, cattle-driving existence common in Somalia. The titres of 11.2% of the positive sera examined singly indicated recent infection. Approximately twice as many subjects from the river villages as from the Mogadishu area were positive for more than one serovar, and a greater number of serovars were recorded from the villages. Antibodies to bratislava serovar, not previously recorded in Africa, were found in 57% of positive subjects, showing the highest prevalence rate among the investigated serovars. Co-antibodies to saprophytic Leptospira biflexa serovars were found in many of the sera.

Adolescent↗
PubMed1982

Seroepidemiology of infection with hepatitis A virus and hepatitis B virus in the Seychelles.

A batch of 417 serum samples obtained from native-born subjects were tested for the presence of hepatitis B surface antigen (HBsAg) and corresponding antibody (anti-HBs), by enzyme-linked immunosorbent assay (ELISA); and antibodies to hepatitis B core antigen (anti-HBc), e-antigen (anti-HBe), and hepatitis A virus (anti-HAV), by radioimmunoassay (RIA). HBsAg was found in only two of the 417 subjects studied. Anti-HBs was detected in 112 samples (26.8%), anti-HBc in 114 (27.3%) and anti-HBe in 31 samples (7.4%). Serologic evidence of a previous or present infection by hepatitis B virus (HBV) was found in 34.5% of the samples studied. Males showed a greater prevalence of anti-HBs and anti-HBc, while anti-HBe was more common in females; however, these differences were not significant. With regard to age, a significantly higher prevalence of anti-HBs (p less than 0.05), anti-HBc (p less than 0.025) and anti-HBe (p less than 0.025) was found in the older age groups. Anti-HAV antibodies were present in 90% of the subjects studied, with no variation between the sexes. The anti-HAV rate in the group under 20 years was similar to that found in the older age groups. The total infection rate of hepatitis B virus in the Seychelles is lower than in other tropical areas, HBs antigen/antibody ratio approaching that in temperate areas. Elucidation of the reasons for the low prevalence of hepatitis B virus carriers among the Sevchelles population requires further investigation.

Adolescent↗