[Methods for studying pleiotropic drug resistance (multidrug resistance, MDR)].
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ATP Binding Cassette Transporter, Subfamily B, Mem↗
Biomedical subjects
M Gobbi
Publications and source records attributed to M Gobbi.
[Immunohistochemical determination of glycoprotein P in 60 non-Hodgkin's lymphomas].
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ATP Binding Cassette Transporter, Subfamily B, Mem↗
CD34 or S313 positive cells selection by avidin-biotin immunoadsorption.
A column immunoadsorption method, based on the high affinity between the protein Avidin and the vitamin Biotin has been used to obtain positive CD34+ or S313+ marrow cells selection. Cell suspensions from marrow samples of six healthy subjects were incubated either the monoclonal antibody S313 or HPCA 1 (My 10-like) and a biotinilated goat anti-mouse Immunoglobulins antiserum, passed over a column containing an Avidin coated Polyacrylamide matrix, at the flow rate of 1 ml/min. The phenotype and the clonogenic efficiency of the recovered adherent cell fraction were studied by cytofluorimetric analysis and haemopoietic progenitors short term cultures. The results obtained show a mean CD34+ and S313+ cells recovery greater than 50% with a lower stem cells enrichment. Although these data could not considered optimal for clinical application in haematologic neoplasias, these preliminary studies demonstrate the possible use of the method for autologous bone marrow transplantation.
Antibodies, Monoclonal↗
Autologous bone marrow transplantation with immunotoxin purged marrow for multiple myeloma. Long term results in 14 patients with advanced disease.
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Antineoplastic Combined Chemotherapy Protocols↗
CEOP regimen in the treatment of advanced low-grade non-Hodgkin's lymphomas: preliminary report.
Between March 1987 and December 1988, 30 previously untreated patients with low-grade non-Hodgkin's lymphomas (NHL), according to the Kiel classification, were treated by a combination of therapy including cyclophosphamide, epirubicin, vincristine, and prednisone (CEOP). Eighteen patients (60%) achieved a complete pathologic remission, and 8 patients (26.6%) had a partial response with a reduction of more than 50% of tumor-related manifestations. Four patients (13.4%) were primary resistant to CEOP. The overall survival was 96.6% with a median follow-up of 25 months from the diagnosis; none of the patients who achieved complete response relapsed at a median follow-up of 21 months from the completion of treatment. Clinical and hematologic toxicities were irrelevant. This regimen was effective in inducing a good remission rate of low-grade NHL, but a longer follow-up for definitive conclusions is warranted.
Adult↗
Regional distribution of low-affinity GABA receptors coupled to benzodiazepine receptor subtypes in rat brain: an autoradiographic evaluation.
Quantitative autoradiography of rat brain coronal sections show that maximum enhancement (more than 80%) of [3H]flunitrazepam binding by GABA occurs in brain regions particularly rich in type I benzodiazepine receptors (inferior colliculus, medium raphe, central gray and substantia nigra); conversely, brain areas where type II predominates show the lowest enhancement by GABA (about 50%). These results, suggesting that the coupling of GABA receptors with type I sites is more efficient than that with type II sites, are at variance with those reported on GABA-benzodiazepine receptors expressed in transfected cells, where the greater GABA potentiation of benzodiazepine binding is due to a subtype of the type II site containing the alpha 3 subunit of the GABAA receptor. One possible explanation of these discrepancies is that the type II receptors found in type I-enriched tissues (inferior colliculus, median raphe, central gray and substantia nigra) are associated with the alpha 3-subunit, while the type II sites present in limbic and cortical regions represent a subpopulation carrying the alpha 2-subunit of the GABAA receptor, with lower GABA potentiation.
Animals↗
In vitro bone marrow purging of multidrug-resistant cells with a mouse monoclonal antibody directed against Mr 170,000 glycoprotein and a saporin-conjugated anti-mouse antibody.
Selective elimination of multidrug resistance-positive cells (LoVo/Dx) was obtained by using the monoclonal antibody MRK 16, which recognizes a surface epitope of the Mr 170,000 glycoprotein, and a sheep anti-mouse immunoglobulin antibody, conjugated to the ribosome-inactivating protein saporin 6. The killing was greatly decreased or even abolished by adding the monoclonal antibody at a 100-fold concentration. Both the MRK 16 and anti-mouse saporin 6 conjugate did not show any killing activity when they were used separately. In cell suspensions composed of 90% normal bone marrow cells and 10% multidrug resistance-positive cells, the monoclonal antibody MRK 16 followed by the anti-mouse immunotoxin caused the elimination of 99% multidrug resistance-positive cells, as revealed by immunofluorescence and immunocytochemistry as well as by a clonal assay. Human normal hematopoietic precursors (granulomonocytic colony-forming units, erythroid burst-forming units, and multipotent granulomonocytic, erythroid, and megakaryocytic-forming units) were not affected by the MRK 16 plus immunotoxin treatment. This technique might be suitable for ex vivo bone purging in an appropriate clinical setting, such as autologous bone marrow transplantation.
Antibodies, Monoclonal↗
Antagonist properties of 1-(2-pyrimidinyl)piperazine at presynaptic alpha 2-adrenoceptors in the rat brain.
The effect of 1-(2-pyrimidinyl)piperazine (PmP), the main metabolite of buspirone, was tested on K(+)-evoked [3H]noradrenaline and [3H]serotonin release from superfused synaptosomes obtained from rat cerebral cortex. PmP had no effects per se, but antagonized the effect of noradrenaline, producing a parallel shift to the right of the noradrenaline inhibition curves. From these data pA2 (apparent affinity) values of 6.8 and 7.3 were calculated for PmP on presynaptic alpha 2-adrenoceptors located on noradrenergic and serotonergic nerve terminals, respectively.
Adrenergic alpha-Antagonists↗
The modulation of [3H]noradrenaline and [3H]serotonin release from rat brain synaptosomes is not mediated by the alpha 2B-adrenoceptor subtype.
The present study aimed at relating the presynaptic alpha 2-adrenoceptors, known to modulate noradrenaline and serotonin release, with the recently described alpha 2A- and alpha 2B-adrenoceptor subtypes. The effects of the agonist oxymetazoline (selective for alpha 2A subtype) and of three adrenoceptor antagonists (idazoxan, 1-(2-pyrimidinyl)piperazine (PmP) and prazosin, the last one known to be alpha 2B selective) were evaluated on [3H]noradrenaline and [3H]serotonin release in superfused synaptosomes from rat brain cortex. These drugs were also tested in [3H]yohimbine binding to human platelet membranes (containing only alpha 2A receptors) and to neonatal rat lung membranes (containing only alpha 2B receptors). The affinity pattern of these compounds at alpha 2A-adrenoceptors in binding studies was oxymetazoline greater than = idazoxan greater than PmP greater than prazosin; at alpha 2B-adrenoceptors it was idazoxan greater than = prazosin greater than PmP = oxymetazoline. Oxymetazoline inhibited with high and similar potencies the K(+)-evoked [3H]noradrenaline and [3H]serotonin release, IC50 18 and 7 nM, respectively; in the same conditions, the IC50 values of noradrenaline were 42 and 168 nM, respectively. The antagonist affinity pattern (antagonism against noradrenaline) was idazoxan greater than PmP greater than prazosin, either on [3H]serotonin release. These results indicate that presynaptic alpha 2 auto- or heteroreceptors do not belong to the alpha 2B subtype and suggest that the modulation of noradrenaline and serotonin release may be mediated by the alpha 2A-adrenoceptor subtype.
Adrenergic alpha-Agonists↗
Regulation of self-major histocompatibility complex reactive human T-cell clones.
The proliferative response of human T-lymphocyte clones, (TLC) specific for self-major histocompatibility complex (MHC) products either alone or associated with PPD epitopes are inhibited in vitro by dexamethasone (DEX) and by a non-specific inhibitory factor(s) (nsINH) produced by PPD-activated T-cells. The inhibiting effect has been investigated by preincubating autoreactive and PPD-specific TLC with nsINH or DEX. Results obtained indicate that T-lymphocytes are the target of these two immunoregulatory molecules. Moreover, the addition of exogenous recombinant interleukin 2 (rIL-2) substantially reverses the inhibition observed in both nsINH- or DEX-treated cultures.
Antigens, Bacterial↗
Improved methods for the determination of 5-bromo-2-deoxyuridine labelling index in clones and colonies growing in plasma clots.
Bromodeoxyuridine (BrdUrd), an analogue of thymidine is one of the most employed marker to detect the S-phase of the cell cycle. Difficulties are described for the in situ detection of S-phase cells in normal and neoplastic growing clones. In this paper we propose new methods for the detection of BrdUrd in neoplastic clones, growing in plasma clots. In particular, these methods are based on the immunocytochemical staining with horseradish peroxidase and alkaline phosphatase, as well as on a new immunofluorescent streptavidin technique. They allow easy detection of S-phase cells with an inverted light microscope.
Antibodies, Monoclonal↗
Immunoglobulin and Myc gene structure in lymphnode biopsies from HIV-positive patients with LAS and lymphoma.
The pattern of immunoglobulin (Ig) gene rearrangement and the genomic structure of the Myc locus were investigated in the DNA of 20 lymphnode biopsies of patients suffering from lymphoadenopathy-associated syndrome (LAS) and from 3 patients with Burkitt's lymphoma. Although polyclonality was the prevalent pattern of Ig gene rearrangement observed in LAS, in 30% of the cases discrete bands of Ig heavy chain gene rearrangement were identifiable due to the presence of monoclonal or oligoclonal cell populations. However, structural alterations of the Myc gene were not detected in any cases. As expected, in all three Burkitt's lymphomas studied, the lymphnode DNA displayed a clonal pattern of Ig heavy chain gene rearrangement. The Myc was altered in two cases, which presented a truncation of the gene beginning within a very short region of the first intron. By contrast, the breakpoint positions on chromosome 14 mapped in different regions of the Ig loci, which in both cases involved the switch (SH) area. Data confirm the relatively common occurrence of oligoclonal expansions within B cells in LAS and the frequent involvement of the Myc oncogene in the process of lymphomagenesis in individuals positive for human immunodeficiency virus (HIV).
AIDS-Related Complex↗
Bone marrow purging by a xanthine oxidase-antibody conjugate.
The selective cytotoxicity of the xanthine oxidase conjugated to an 8A monoclonal antibody recognizing a human plasma cell-associated antigen has been described. The selectivity and the toxicity of the hypoxanthine/conjugated xanthine oxidase system was increased by removing the excess of conjugate and by adding chelated iron. Under these experimental conditions the cytotoxicity of the conjugate exceeded that of free xanthine oxidase by one order of magnitude. The conjugate effectively purged bone marrow from infiltrating neoplastic plasma cells and added target Raji cells, provided blood was removed and bone marrow peroxidases were exhausted. In conditions of purging effectiveness the conjugate had no toxicity to CFU-GM. No toxicity to mice was observed after i.v. injection of xanthine oxidase-antibody conjugate up to 2.9 U/kg body weight. Thus the hypoxanthine/conjugated xanthine oxidase system could be an effective and nontoxic tool for the ex vivo bone marrow purging in multiple myeloma patients for autologous transplantation.
Antibodies, Monoclonal↗
Benzene in the blood and breath of normal people and occupationally exposed workers.
Benzene was measured in blood and alveolar air of 168 men, aged 20-58 years, subdivided into four groups: blood donors, hospital staff, chemical workers occupationally exposed to benzene, and chemical workers not occupationally exposed to benzene. The group of exposed workers was employed in work places with a mean environmental exposure to benzene of 1.62 mg/M3 (8 hr TWA). Non-exposed workers were employed elsewhere in the same plant, with an environmental exposure to benzene lower than 0.1 mg/M3. Blood and alveolar air samples were collected in the morning, before the start of the work shift for the chemical workers. The group of exposed workers was found to be significantly different from the other three groups, both for blood and alveolar benzene concentrations. The mean blood benzene concentration was 789 ng/l in the exposed workers, 307 ng/l in the non-exposed workers, 332 ng/l in the hospital staff, and 196 ng/l in the blood donors. Apart from the exposed workers, blood benzene concentration was significantly higher in smokers than in non-smokers. The mean alveolar benzene concentration was 92 ng/l in the exposed workers, 42 ng/l in the non-exposed workers, 22 ng/l in the hospital staff, and 11 ng/l in the blood donors. Alveolar benzene concentration was significantly higher in smokers than in non-smokers in the groups of the hospital staff and non-exposed workers, but not in the blood donors and exposed workers. In the three groups without occupational exposure considered altogether, the alveolar benzene concentration correlated significantly with environmental benzene concentration measured at the moment of the individual examinations, both in the smokers (r = .636; p less than .001) and non-smokers (r = .628; p less than .001). In the same three groups and in the exposed workers, alveolar benzene concentration showed a significant correlation with the blood benzene concentration.
Adult↗
Breath and blood levels of benzene, toluene, cumene and styrene in non-occupational exposure.
Benzene, toluene, cumene and styrene were measured in the breath and blood of two groups of individuals. The first group included individuals belonging to a hospital staff, the second group included chemical workers who were not exposed to the abovementioned chemicals. The chemical workers were examined in plant infirmaries on the morning before the start of the workshift, and the hospital staff in the hospital infirmaries. One environmental air sample was taken in the infirmaries for each individual at the moment of the biological samplings. The environmental concentrations of benzene and styrene were significantly higher in the infirmaries of the chemical plant than in the infirmaries of the hospital. On the other hand, the environmental concentrations of toluene and cumene were not significantly different in the plant infirmaries and in the hospital infirmaries. In the hospital staff the alveolar concentrations of benzene, toluene and styrene were significantly lower than those in the chemical workers. In the hospital staff the blood concentrations of benzene, toluene and styrene were not significantly different from those in the chemical workers. Only the blood cumene concentration was significantly higher in the chemical workers. In hospital staff, smokers showed alveolar and blood concentrations of benzene and toluene that were significantly higher than those measured in the non smoker hospital staff. With reference to chemical workers, only alveolar benzene concentration was significantly higher in smokers than in non smokers.(ABSTRACT TRUNCATED AT 250 WORDS)
Benzene↗
Profile of in vitro binding affinities of neuroleptics at different rat brain receptors: cluster analysis comparison with pharmacological and clinical profiles.
A series of 21 neuroleptics with different chemical structures (phenothiazines, thioxanthenes, dibenzodiazepines, butyrophenones, benzamides, etc.) was examined for their in vitro interactions with 12 neurotransmitter binding sites in the rat brain (alpha- and beta-noradrenergic, dopaminergic, muscarinic, serotoninergic, histaminic, and opioid receptors, calcium channels, and serotonin uptake binding sites). The biochemical profile obtained from the binding data was compared with reported pharmacological and clinical profiles for this class of compounds by cluster analysis. Cluster analysis on binding data classified the compounds in three main subgroups: benzamides, compounds with an affinity mainly for DA2 and 5-HT2 receptors and inactive at muscarinic receptors, and compounds with a high affinity for alpha 1-adrenergic receptors and muscarinic receptors. The main subgroups resulting from cluster analysis of previously published pharmacological and clinical data for neuroleptics contain compounds common to the present study, with some correlations. The results extend previous observations that a complete binding profile corresponds to the pharmacological and clinical profile of this class of compounds.
Animals↗
An immunotoxin containing momordin suitable for bone marrow purging in multiple myeloma patients.
Attempts have been made by a number of methods to eliminate minimal residual disease from bone marrow to be reinfused in autologous transplantation. In this paper we describe a conjugate containing a monoclonal antibody, named 8A, recognising a plasma cell-associated antigen, and momordin, a ribosome-inactivating protein similar to the ricin A-chain. This immunotoxin is active on target cell lines and on neoplastic plasma cells, while myeloid progenitors are fairly resistant. The conjugate is shown to be acceptable for ex vivo purging in autologous bone marrow transplantation in multiple myeloma patients.
Antibodies, Monoclonal↗
Bone marrow purging for multiple myeloma by avidin-biotin immunoadsorption.
Avidin-biotin immunoadsorption, a technique based on the high affinity between the protein avidin and the vitamin biotin, has been used to remove neoplastic plasma cells from the bone marrow of patients with multiple myeloma. Buffy coat cells obtained from 25 patients were first incubated with monoclonal antibodies (MoAb) capable of recognizing plasma cell-associated antigens (i.e., 8A, 8F6, 62B1, and cocktails of 8A plus 8F6 or 62B1), then with biotinylated goat antimouse immunoglobulin, and passed over a column containing avidin conjugated to Sepharose GMB. Both non-linked and linked cells were analyzed by immunofluorescence and morphological staining. The results showed that over 98% of plasma cells were removed by using 8A or 8F6 alone, while 99.5% +/- 0.4 SD of plasma cell purging was achieved with 2 associated MoAb. In addition, the overall recovery of committed granulocyte-macrophage (CFU-GM),* erythroid (BFU-e), and multilineage (CFU-GEMM) progenitors after column treatment ranged from 39% +/- 15 SD to 50% +/- 6 SD, from 15% +/- 2 SD to 39% +/- 7 SD, and from 16 +/- 4 SD to 64% +/- 10 SD, according to the MoAb employed. On this basis avidin-biotin immunoadsorption appears to be a suitable technique for ex-vivo manipulation of bone marrow infiltrated by neoplastic plasma cells.
Antibodies, Monoclonal↗