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Biomedical subjects

M Gobbi

Publications and source records attributed to M Gobbi.

At least 163 records · Page 9Linked to original sources
PubMed1988

An immunotoxin containing a rat IgM monoclonal antibody (Campath 1) and saporin 6: effect on T lymphocytes and hemopoietic cells.

The elimination of the cells responsible for graft-versus-host disease in allogeneic bone marrow transplantation has been attempted with a variety of methods, including the use of the ribosome-inactivating toxin ricin bound to monoclonal antibodies acting as carriers. However the high nonspecific toxicity of these immunotoxins containing the whole toxin greatly limited clinical application. Toxicity can be reduced using the A-chain of ricin or other ribosome-inactivating proteins (RIPs) which are devoid of a B-chain with lectin properties. We used saporin 6 purified from Saponaria officinalis seeds, which was conjugated with the rat IgM monoclonal antibody Campath 1 specific for mature T and B lymphocytes as well as for monocytes. The immunotoxin retained both RIP and antibody activity, inhibiting protein synthesis both in a cell-free system and in cells bearing the Campath 1 antigen; it also abolished methyl 3H-thymidine uptake in phytohemagglutinin-stimulated T lymphocytes. Myeloid progenitors were largely spared as shown by myeloid stem cell (CFU-GM) growth which was scarcely affected. Toxicity of the immunotoxin to cell lines not expressing the antigen recognized by Campath 1 monoclonal antibody was not greater than the toxicity due to free saporin 6, while the immunotoxin was more toxic to mice than free saporin.

Animals↗
PubMed1988

In situ immunocytochemical staining of cell colonies growing in plasma clot.

The procedures involving the growth of cell colonies in semi-solid media, such as methyl cellulose or agar, provide a score of colony-forming-units (CFUs) by means of morphology, and allow the application of cytochemistry. However, a better characterization of the growing cells by employing monoclonal antibodies is impaired by the medium itself. Plasma clot is a possible alternative, allowing immunofluorescence as well as immunoenzymatic techniques. We have developed a staining procedure which can be performed using both peroxidase- or alkaline phosphatase-conjugated reagents; the colonies, growing in plasma clot, can be stained in situ, without transferring the cells. In this paper we report on the study of six different cell lines stained by immunocytochemical techniques with appropriate monoclonal antibodies.

Antibodies, Monoclonal↗
PubMed1988

Different components of 3H-imipramine binding in rat brain membranes: relation to serotonin uptake sites.

In the present paper we confirm and extend previous studies showing heterogeneous 3H-imipramine (3H-IMI) binding sites. Inhibition curves of various drugs (serotonin, imipramine, desmethyl-imipramine, d-fenfluramine, d-norfenfluramine and indalpine, a potent serotonin uptake inhibitor) obtained using 2 nM 3H-IMI and in presence of 120 mM NaCl, confirmed the presence of at least three 3H-IMI binding sites: two of these (high and low affinities) were serotonin-insensitive while the third one was selectively inhibited by serotonin and indalpine with nanomolar affinities. Moreover, this last component was found to be selectively modulated by chronic imipramine treatment thus suggesting a closer relation to serotonin uptake mechanism. These data indicate that the use of a more selective inhibitors of the serotonin-sensitive component (like indalpine or serotonin itself) to define non specific 3H-IMI, may be of help in understanding its relation with serotonin uptake system.

Animals↗
PubMed1988

Immunocytochemical evaluation of the percentage of proliferating cells in pathological bone marrow and peripheral blood samples with the Ki-67 and anti-bromo-deoxyuridine monoclonal antibodies.

The monoclonal antibody Ki-67, directed against a nuclear antigen expressed by dividing cells in all the phases of cell cycle except G0 and early G1, was used in combination with an anti-BrdU monoclonal antibody, reacting selectively with cells in S-phase, for assessing the percentage of proliferating cells in bone marrow and peripheral blood samples from patients with lymphoma, leukaemia and multiple myeloma. Immunocytochemical labelling of proliferating cells was performed on marrow frozen sections and/or cytospins using an immunoalkaline phosphatase (APAAP) technique that made it possible to obtain proliferative index measurements in a few hours in contrast to the 3-7 d needed with tritiated thymidine. In the 54 marrow lymphoma cases studied a highly significant correlation was observed between the proportion of Ki-67 (+) cells and the separation into low- and high-grade malignant lymphomas according to the Kiel classification. In patients with multiple myeloma at the first diagnosis, the percentage of Ki-67 (+) cells was low (6-10%). In contrast, a high percentage of Ki-67 (+) cells (40-50%) was observed in a young adult with multiple myeloma, in a patient who first presented at the clinical observation with an extradural mass and in three patients who developed extramedullary masses several years after the initial diagnosis of myeloma. In acute lymphoblastic leukaemias of common type the mean value of Ki-67 labelling was 31.3%. Because of their simplicity and rapidity, immunocytochemical techniques may be expected to replace autoradiography and flow cytometry for the detection of proliferating cells in haematological samples.

Antibodies, Monoclonal↗
PubMed1988

Cytoskeleton organization of normal and neoplastic lymphocytes and lymphoid cell lines of T and B origin.

An anomalous organization of the cytoskeleton has been described in lymphocytes from chronic lymphatic leukaemia and in only few cell lines. We have now studied normal and neoplastic lymphocytes and lymphoid cell lines of both T and B lineage in order to detect morphological differences in the expression of microfilaments and intermediate filaments. Microfilaments appear to be well expressed by all the B cells, whereas a rich network of intermediate filaments is present in T cells and plasma cells. Most prominent changes occur in the latter system, which is almost lacking in cells of B chronic lymphatic and hairy cell leukaemia. Although the significance of the present findings is not yet clear, one might speculate that such alterations account for some of the aberrant functions and peculiar biologic properties of neoplastic lymphocytes.

Actin Cytoskeleton↗
PubMed1988

M-2 protocol for melphalan-resistant and relapsing multiple myeloma.

33 patients with advanced refractory multiple myeloma received a combination of vincristine, cyclophosphamide, carmustine, melphalan and steroids (M-2 protocol). 20 of them had failed prior chemotherapy with alkylating agents and the remaining 13 patients had relapsed after a response to these drugs. An objective tumour cell mass reduction (greater than or equal to 50%) was achieved in 17% of the patients (6% of previously nonresponders and 33% of previously relapsing), while 9 additional patients improved (30-50% tumour reduction), for an overall response rate of 47% (39% for previously nonresponders and 58% for previously relapsing). The median duration of response was 7 months. Thrombocytopenia was the most common toxicity encountered in the study (39% of cases). Our findings indicate that M-2 protocol is an effective salvage treatment for patients who relapse from previous chemotherapy with alkylating agents. In contrast, results in patients who are primarily resistant to these drugs justify the search for different treatment programmes which can produce greater degrees of tumour reduction.

Adult↗
PubMed1988

Biochemical characterization of a new highly cardioselective beta-adrenoceptor antagonist.

P0160 (1-phenyl-3-(2-(3-(2-cyanophenoxy)-2-hydroxypropyl)amino) ethylhydantoin HCl) is an aryloxypropanolamine which contains a ureido group as part of the hydantoin ring. This molecule was synthesized to obtain a more cardioselective beta-adrenoceptor blocker. Preliminary data have shown that it is as potent as propranolol and four times more cardioselective than atenolol in pharmacological tests in-vitro and in the conscious rat. In the present study we evaluated the interaction of P0160 with beta-adrenoceptors by radioreceptor binding studies and by measuring adenylate cyclase activity coupled to beta-adrenoceptors. The data indicate that P0160 binds with nanomolar affinity to beta-adrenoceptors labelled with [3H]DHA in the rat heart, but with micromolar affinity in the rat lung. Its binding is stereospecific, the S-(-)isomer being 200 times more active than the R-(+) form. P0160's selectivity between cardiac beta 1- and beta 2-receptors was 1388, about 60 times that for metoprolol. Analysis of the thermodynamic characteristics of P0160's interaction with rat heart beta-adrenoceptors indicated antagonist properties of the same order of magnitude as propranolol, as confirmed by adenylate cyclase studies. These data indicate that P0160 is a potent, specific and selective beta 1-adrenoceptor antagonist, and give a molecular explanation for the cardioselective activity found in pharmacological tests.

Adenylyl Cyclases↗
PubMed1988

HIV-related malignant lymphoma: a report of 46 cases observed in Italy.

We report 36 patients with non-Hodgkin's lymphomas (NHL) and 10 patients with Hodgkin's disease (HD), predominantly intravenous drug abusers (IVDA; 35 patients), diagnosed in 16 different Italian centers. The group of NHL has a median age of 26 years (range 16-64): 26 were IVDA, 3 polytransfused, 3 IVDA and homosexual men, 2 homosexual men and 2 without apparent risk for AIDS but carrying HIV antibodies. 81% of the evaluable patients had high-grade NHL (32% Burkitt's type) according to the Working Formulation, 15% intermediate and 4% low-grade. Out of 23 patients with stage reported, 16 (70%) were stage IV, 2 (9%) stage III, 1 (4%) stage II and 4 (17%) stage I (CNS involvement). The group with HD has a median age of 25 years (range 20-40), 9 were IVDA and 1 IVDA and homosexual. Of the 7 patients with subtype reported, 4 patients had nodular sclerosis and 3 mixed cellularity subtype. Stage III and IV were reported in 66% of the patients. The median survival is 4 months for NHL and 10 months for HD. The most common cause of death is opportunistic infection in 86% of the evaluable cases.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Essential mixed cryoglobulinemia, type II: a manifestation of a low-grade malignant lymphoma? Clinical-morphological study of 12 cases with special reference to immunohistochemical findings in liver frozen sections.

Twelve patients with clinical and laboratory findings typical of essential mixed cryoglobulinemia, type II (EMC II) underwent multiple liver and bone marrow biopsies. In 9 of 12 cases (all hepatitis B surface antibody-negative), routine histology revealed patent infiltration of liver portal tracts, lobules and sinusoids by small lymphocytes provided with cytological characteristics closely resembling those of the LP immunocytoma of the Kiel classification. At immunophenotyping on frozen sections, these elements expressed the CD22 antigen (marker of B cells) and bore the same type of immunoglobulin (IgM/k = 8, IgM/lambda = 1) as the monotypic component in the serum. Furthermore, in 7 of 9 patients repeated bone marrow needle biopsies showed multiple foci of infiltration by plasmacytoid cells, often with paratrabecular location. In the remaining 3 cases (all hepatitis B surface and core antigen-positive), liver biopsies were consistent with a diagnosis of cirrhosis (two) or chronic active hepatitis (one). In two of them, however, Jamshidi needle biopsy evidenced bone marrow infiltrates quite similar to those observed in the other group. On the basis of these findings, the authors discuss the hypothesis that most EMC II are substained by a low-grade malignant lymphoma.

Adult↗
PubMed1988

Cyclosporin A in the treatment of CLL associated PRCA and bone marrow hypoplasia.

Three patients (1 PRCA-T-CLL, 1 PRCA-B-CLL, 1 B-CLL aplasia) were treated with cyclosporin A (CS-A). Patient no 1 had relapsed during steroid therapy and the remaining two patients had been resistant to conventional immunosuppression. CS-A produced in all cases a prompt remission (within 1-4 weeks) of bone marrow failure. Mild reversible renal toxicity was the only side-effect noted. CS-A might be tried in every case of CLL-associated bone marrow failure.

Adult↗
PubMed1988

Induction and regulation of cytotoxic T cells by microbial antigens and recombinant interleukin 2.

The proliferation and development of cytotoxic T cells was investigated in human peripheral blood mononuclear cell (PBMC) cultures stimulated with an antigenic extract from Candida albicans (MPPS), or with the purified protein derivative from Mycobacterium tuberculosis (PPD), or with human recombinant interleukin 2 (rIL-2). Microbial antigen- and rIL-2-induced cytotoxic T cells were able to lyse both natural killer (NK) sensitive and resistant targets. No correlation was observed between the development of T cell cytotoxicity and interferon (IFN) production in vitro. The addition of anti-class II monoclonal antibodies at the beginning of MPPS/PPD-stimulated cultures inhibited the cell proliferation, IFN production and T cell cytotoxicity, while all these cellular activities were not inhibited by anti-class II antibodies in rIL-2-stimulated cultures. Finally, antibodies to class I determinants inhibit T cell cytotoxicity, suggesting a role of such determinants in the development of the non-adaptive immunity to microbial infections.

Adult↗
PubMed1988

Selective cytotoxicity of an oxygen-radical-generating enzyme conjugated to a monoclonal antibody.

The monoclonal antibody 8A, which recognizes a human plasma cell-associated antigen, was covalently linked to xanthine oxidase in a conjugate maintaining both immunological and enzymatic properties. A significant degree of target cell lysis was obtained at an enzyme concentration that was ineffective on non-target cells and on myeloid staminal cells (CFU-GM). The cytotoxic activity was abolished by an excess of antibody, by allopurinol and by superoxide dismutase and catalase. A possible use of the conjugate for bone marrow purging in multiple myeloma patients is suggested.

Antibodies, Monoclonal↗
PubMed1987

New aggressive variant of suppressor/cytotoxic T-CLL.

Three cases of CD8+ CLL are reported. The patients are young (28, 18, 27 years old). The leukemia cells are predominantly small lymphocytes with irregular nuclei bearing notches and lobations. Cytoplasmic azurophilic granules are absent. Cytochemistry shows periodic acid-Schiff granular, alpha-naphthylacetate esterase focal, and acid phosphatase focal/granular positivities. Immunophenotypically cells are CD2+, CD3+, and CD8+ and lack CD4 as well as B-cell and NK cell antigens. All patients died within 20, 16, and 9 months, respectively. The clinicopathologic features of these cases differ clearly from those of the CD8+ CLL with azurophilic granules. These three cases represent a morphologically distinctive and more aggressive variant of CD8+ CLL.

Adolescent↗
PubMed1987

Close association between antibodies to cytoskeletal intermediate filaments, and chronic graft-versus-host disease.

Chronic graft-versus-host disease can mimic various autoimmune disorders, although autoantibodies are rarely detected in the sera of affected patients. Antibodies to cytoskeleton are a frequent finding in patients affected by autoimmune disorders. In all the sera of 16 patients who were submitted to allogeneic bone marrow transplantation, we have found antibodies against cytoskeletal intermediate filaments. Moreover, the titer of such antibodies is quite elevated when compared with those reported in autoimmune disorders. A statistically significant difference between the titers found in patients without and with cGVHD (median 1:40 vs. 1:256, P less than 0.05) has been found. This would suggest that such antibodies might be relevant in monitoring clinical course. Furthermore, since certain cytoskeleton antigens have been shown to be expressed also on cell membrane, antibodies against intermediate filaments might also play a more important role by interfering with such surface structures.

Adolescent↗
PubMed1987

Heterogeneity of large granular lymphocyte proliferations: morphological, immunological and molecular analysis in seven patients.

The clinical, morphological, immunological and molecular features of seven patients with a stable picture of chronic granular lymphocytosis, observed over a period of up to 4 years, were studied. Mild splenomegaly was detected in one patient, while lymphoadenopathy and hepatomegaly were absent. Surface marker analysis showed in five patients the common membrane phenotype of granular T-cell lymphocytosis (T3+, T4-, T8+, Leu-7+); of the remaining two, one presented an unusual phenotype (T3+, T4+, T8+) and the other showed a marked positivity with the Leu-11 and M1 monoclonal antibodies, but lacked the T3, T4, T8 antigens. Three cases had a low (less than 30%) expression of the T1 antigen. Functional studies showed that the proliferative response to PHA and the NK function were reduced in four of the seven cases. Molecular analysis, performed in six cases, revealed a monoclonal rearrangement of the T-cell receptor beta-chain gene in three, a polyclonal T-cell configuration in two and a germ-line arrangement in the last. All three monoclonal cases showed a depressed NK activity and two a reduced PHA response. The results of this study document the heterogeneity of granular lymphocyte expansions and suggest that the clonal or reactive nature of these often indolent proliferations, suspected on the basis of immunologic functional studies, may be recognized at the DNA level.

Adult↗