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Biomedical subjects

G Mariani

Publications and source records attributed to G Mariani.

At least 19 recordsLinked to original sources
PubMed1995

Initial tumor targeting, biodistribution, and pharmacokinetic evaluation of the monoclonal antibody PAM4 in patients with pancreatic cancer.

This pharmacokinetic study was performed to assess the potential usefulness of the murine monoclonal antibody (MoAb) PAM4-IgG1 as an immunotargeting agent for pancreatic cancer imaging or therapy. This MoAb reacts specifically with mucin purified from human pancreatic cancer. 131I-labeled PAM4-IgG1 was injected i.v. into five patients with suspected pancreatic cancer. Whole-body scans and spot views of the abdominal area were recorded with a computerized gamma camera, and specific regions of interest were drawn over the liver and spleen to define the kinetics of activity in these organs. Blood samples taken from 0.1-144 h after injection served to define the kinetics of plasma distribution and removal of activity from the body. Surgery confirmed pancreatic cancer in four of the five patients, whereas chronic pancreatitis was present in the fifth patient; in all four pancreatic cancer patients, immunostaining with the MoAb PAM4 demonstrated the presence of the specific antigen, with a cytoplasmic and endoluminal/secretory pattern of distribution. Nonspecific radioactivity accumulation in the liver, spleen, and bone marrow was low, linked essentially to the blood pool effect of circulating activity in these organs. The overall quality of scintigraphic maps recorded over the abdomen was quite satisfactory due to the low liver and spleen activity, with good scintigraphic demonstration of the pancreatic cancers (either primary or metastatic); the patient subsequently found to have pancreatitis failed to show PAM4 targeting. Except in one patient with widespread peritoneal metastases (in whom these tumor implants were detected scintigraphically already 24-48 hours after tracer injection), scintigraphic evidence of the tumor lesions was usually late, starting at about 72-96 h after tracer injection. The results obtained in this preliminary study indicate the potential usefulness of MoAb PAM4 for immunoscintigraphy in patients with either primary and/or recurrent pancreatic cancer while also suggesting that the use of the faster-clearing Fab fragments of this MoAb probably would result in improved immunoscintigraphic properties.

Aged↗
PubMed1995

In vitro human immunodeficiency virus-1 infection of purified hematopoietic progenitors in single-cell culture.

Uni- or multi-lineage suppression of hematopoiesis is observed in the majority of acquired immunodeficiency syndrome (AIDS) patients. The mechanism(s) underlying these abnormalities is not understood: particularly, the human immunodeficiency virus (HIV) infection of hematopoietic progenitor and stem cells (HPCs/HSCs) is highly controversial. We report that CD34+ HPCs from adult peripheral blood (PB) are in part CD4+ and susceptible to in vitro HIV infection. Primitive CD34+ HPCs were approximately 80% purified from PB. Double labeling for CD34 and CD4 membrane antigens was shown for 5% to 20% of the purified cells, thus suggesting their potential susceptibility to HIV-1 infection. The enriched HPC population, challenged with purified or unpurified HIV-1 strains, was cloned in unicellular methylcellulose culture. The single colonies generated by erythroid burst-forming units (BFU-E), granulocyte-macrophage colony-forming units (CFU-GM), and granulocyte-erythroid-macrophage-megakaryocyte colony-forming units (CFU-GEMM) were analyzed for the presence of HIV, ie, for gag DNA, tat mRNA, and p24 protein by PCR, reverse transcription PCR (RT-PCR), and enzyme-linked immunosorbent assay, respectively. In the first series of experiments incubation of HPCs with HIV-1 at multiplicities of infection (MOI) ranging from 0.01 to 10 TCID50/cell consistently yielded an 11% to 17% infection efficiency of BFU-E-generated colonies, thus indicating the sensitivity of HPCs to in vitro HIV infection. An extensive series of experiments was then performed on HPCs challenged with HIV at 0.1 MOI level. In the initial studies proviral gag sequences were detected in 9.2% of 121 analyzed CFU-GM colonies. In further experiments tat mRNA was monitored in 17% and 23% of BFU-E and CFU-GM colonies, respectively, but never in CFU-GEMM clones. Finally, 12% of CFU-GM clones and rare erythroid bursts were shown to be positive for the p24 viral protein. In control studies, purified HPCs grown in liquid suspension culture were induced to terminal unilineage erythroid, monocytic, or granulocytic differentiation: monocytes were consistently HIV-infected, whereas mature-terminal erythroblasts and granulocytes were not. Our observations indicate that a minority of primitive HPCs, but not of the multipotent type, is susceptible to in vitro HIV infection. These observations may reflect on the in vivo hematopoietic impairment in AIDS patients; more important, they provide an experimental model for studies on HIV hematopoietic infection and in vitro tests for anti-HIV HSC gene therapy.

Adult↗
PubMed1995

Promyelocytic leukemia-specific PML-retinoic acid alpha receptor fusion protein interferes with erythroid differentiation of human erythroleukemia K562 cells.

Acute promyelocytic leukemia (APL) is characterized by a t(15;17) chromosomal translocation with breakpoints within the retinoic acid alpha receptor (RAR alpha) gene on 17 and the PML gene, which encodes a putative transcription factor, on 15. A PML-RAR alpha fusion protein is formed as a consequence of the translocation. We show here that expression of the PML-RAR alpha protein in K562 erythroleukemia cells results in a reduced expression of erythroid differentiation markers and a reduced sensitivity to the erythroid differentiative action of heme. Overexpression of RAR alpha, but not of PML, elicited a similar inhibition of K562 erythroid differentiation. These findings indicate that overexpression of either RAR alpha or PML/RAR alpha interferes with erythroid differentiation and support the hypothesis that RAR alpha is involved in the regulation of normal hematopoiesis and alteration of the RAR alpha signaling by PML/RAR alpha is implicated in the promyelocytic leukemogenesis.

Cell Differentiation↗
PubMed1995

[The evolution of the therapeutic choice in patients with the outcomes of non-Q myocardial infarct: 2 periods compared].

BACKGROUND: Over the last years there has been a tremendous increase in coronary angioplasty procedures (PTCA), due to the availability of better materials and to the refinement of operators skill. It is not known however if this "PTCA boom" has modified our approach to the patients with particular clinical situations, such as those with non-Q wave myocardial infarction. The purpose of this study was to verify, in patients undergoing coronary angiography for clinical reasons after a non-Q wave myocardial infarction, the clinical decision concerning the therapeutical choice in two different periods (101 patients in 1988 vs. 102 patients in 1992). METHODS AND RESULTS: Patients in the two groups had similar clinical manifestations whereas patients observed in 1992 had more frequently 2-vessel disease than single vessel disease as compared to patients studied in 1988 (p < 0.05). The distribution of patients with normal coronary arteries or with 3-vessel disease was similar in the two periods. In 1988 medical therapy was the most recommended treatment at discharge (47%), followed by aorto-coronary bypass (29%) and coronary angioplasty (24%). On the contrary, in 1992 PTCA was performed in 48% of patients, medical therapy was recommended in 28% while the incidence of coronary surgery was reduced to 24% (p < 0.01). From a clinical point of view a significant increase in PTCA procedures was seen in patients presenting with unstable angina after the non-Q wave myocardial infarction (54% of these patients undergoing PTCA in 1992 vs. 30% in 1988, p = 0.03) and in patients with effort angina and a positive exercise test at low workload (53% of these patients undergoing PTCA in 1992 vs. 22% in 1988, p < 0.05). Moreover, in 1992 PTCA procedures increased in patients with single vessel disease (64% in 1992 vs. 49% in 1988) and in patients with 2-vessel disease (64% in 1992 vs. 9% in 1988). Therefore, in these patients the need of aorto-coronary by pass was reduced from 39% in 1988 to 19% in 1992 (p < 0.05). The success rate of PTCA procedures was 98% in 1992 and 83% in 1988. No major complications were observed in the two study periods and no patients underwent urgent coronary surgery. CONCLUSIONS: These data show an increase in PTCA procedures over the last years in patients undergoing coronary angiography for clinical reasons after a non-Q wave myocardial infarction. The greater experience of operators allowed for improved results, thus reducing the need of coronary surgery in these patients.

Adult↗
PubMed1994

Efficient transfer of selectable and membrane reporter genes in hematopoietic progenitor and stem cells purified from human peripheral blood.

We have utilized highly purified hematopoietic progenitor and stem cells (HPCs, HSCs) from normal peripheral blood to develop methodology for: (a) efficient transfer into HPCs of a non-hematopoietic membrane reporter, i.e., the nerve growth factor receptor complementary DNA; and (b) effective gene transduction of putative HSCs, i.e., cells initiating Dexter-type long-term culture (LTC-ICs). Purified HPCs induced into cycling by growth factors (interleukin 3, interleukin 6, c-kit ligand) were transduced with the N2 retroviral vector containing the neomycin resistance (neor) gene. More than 80% of transduced HPCs were resistant to the toxic G418 level. Thereafter, the HPCs were effectively transduced with the LNSN retroviral vector containing a nerve growth factor receptor complementary DNA; the nerve growth factor receptor was detected on > or = 18% of the transduced HPCs. These experiments provide a new tool from which (a) to monitor expression of a transduced membrane report on hematopoietic cells, particularly at the level of HPCs/HSCs, and (b) to characterize the transduced cells by double- and triple-labeling membrane antigen analysis. Purified HPCs/HSCs grown in Dexter-type LTC were transduced at 1 week by exposure to supernatant N2 retroviral particles in the absence of exogenous hematopoietic growth factors. The procedure, devoid of toxic effects, allowed an efficient neor transduction into LTC-ICs. Thus, we consistently detected neomycin-resistant mRNA in the clonal progeny of HPCs produced in LTC at 5-8 weeks in both the nonadherent and adherent fractions; this timing of expression coincides with that of HPC production by LTC-ICs, thereby indicating the effective transduction of the LTC-ICs. These experiments represent a first step toward development of preclinical models for gene transfer into human peripheral blood HSCs by complex retroviral vectors.

Adult↗
PubMed1994

Protein S and HIV infection. The role of anticardiolipin and anti-protein S antibodies.

It has recently been reported that a large proportion of patients with HIV infection have low free protein S levels. In this study we show that protein S (PS) activity levels, as well as PS antigen (Ag), were significantly lower in 35 HIV-1 infected patients than in the control population (p < 0.001). When we divided HIV infected patients into three groups according to their CD4+ counts, we found that PS levels were significantly lower in patients with < 100 CD4+ cells/ul. In order to investigate the possible role of (auto)immune response in the pathogenesis of PS deficiency, the presence of anticardiolipin antibodies (aCL) and/or of the specific antibodies to protein S was evaluated. A high prevalence (77.1%) of aCL in both symptomatic and asymptomatic subjects was observed. The screening for specific anti-PS antibodies, performed by immunoblotting, showed an overall positivity of 28.6% in anti-HIV+ patients, with a higher prevalence in symptomatic than in asymptomatic patients. Interestingly, the prevalence of the positivity for anti-PS antibodies was found to be higher in anti-HIV+ patients with PS levels < 50%. Taken collectively, our findings suggest that at least one of the mechanisms through which PS levels are decreased in HIV infection, is due to the presence of specific autoantibodies.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Biodistribution and pharmacokinetic screening in humans of monoclonal antibody AR-3 as a possible immunoscintigraphy agent in patients with pancreatic cancer.

This pharmacokinetic study was performed in order to assess the potential usefulness of the murine monoclonal antibody (MoAb) AR-3-IgG1 as an immunoscintigraphy agent for pancreatic cancer. This MoAb, which defines a mucin-like antigen (CAR-3) expressed by a large fraction of pancreatic cancers, shows in fact favourable in vivo localizing properties in the experimental animal model of human tumor xenograft. 131I-AR-3-IgG1 was injected i.v. into 5 patients with suspected pancreatic cancer. Whole-body maps and spot views of the abdominal area were recorded with a computerized gamma-camera, and specific regions of interest drawn over the liver and spleen helped to define the kinetics of activity in these organs. Blood samples taken from 0.1-144 hours post-injection and daily urine collections over the same interval served to define the kinetics of plama distribution and removal of activity from the body. Different multicompartmental models were tested to fit the experimental data, assuming as the starting hypothesis that there was to be significant nonspecific tracer accumulation in the liver, spleen and bone marrow, as already observed for the majority of radioiodinated murine MoAbs injected into humans. Surgery confirmed pancreatic cancer in 3 out of the 5 patients (chronic pancreatitis and periampullary cancer in one each); in all these 3 patients immunostaining with the MoAb AR-3 demonstrated the presence of the CAR-3 antigen (with a cytoplasmic and endoluminal/secretory pattern of distribution). Nonspecific radioactivity accumulation in the liver, spleen and bone marrow was extremely low, linked essentially to the blood pool effect of circulating activity in these organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Critical evaluation of endothelins assay.

Endothelin(s) is (are) generally measured by highly-sensitive RIA (radioimmunoassay) or sandwich-EIA (enzyme immunoassay) methods after preliminary extraction and chromatographic purification using Sep-Pak C18 cartridges; however, there is no general consensus about the range of endothelin circulating levels in healthy subjects and patients. We have evaluated the analytical performance of two commercial RIAs for plasma endothelin-1 assay (supplied by Peninsula Laboratories, Belmont, California, and by Biomedica Gruppe, Biomedica Gesellschaft mbH, Vienna, Austria) in order to verify whether differences in extraction procedures, antibody affinities or standard preparations can explain the different results obtained by these two RIAs. The RIA kits tested in the present study showed some differences in the analytical performance; in particular, different antibody specificities have been observed. The concentration range of endothelin(s) assayed with an imprecision better than 15%, which can be considered the working range, was wider for the Peninsula than for the Biomedica kit (i.e. from 1.6 to 50 fmol/tube vs 0.7 to 10 fmol/tube), whereas the two RIA kits showed similar sensitivity (i.e. about 0.2 fmol/tube). Taking into account the working range and sensitivity of the two RIAs to measure with an acceptable error the samples of normal subjects and the most part of patients, > or = 3-ml volumes of plasma must be extracted by Sep-Pak C18 cartridges and then measured by RIA. Owing to the central role played by the endothelin superfamily in several pathophysiological conditions, it is important to have a reliable assay for the measurement of these peptides in biological fluids and tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Immune tolerance in hemophilia-principal results from the International Registry. Report of the factor VIII and IX Subcommittee.

40 Hemophilia Centers from the USA, Canada, Europe and Japan referred to the International Registry 204 patients with haemophilia A, treated by Immune Tolerance (IT) Protocols over the past two decades because of the presence of an inhibitor to FVIII. 82% of the patients were high responders, while IT was started with low levels of inhibitor (< 10 BU) in most (57.3%) of the cases. 69 patients (33.8%) were given the highest FVIII dosage (> or = 200 IU/kg/day), 71 (34.8%) intermediate dosages (50- < 200) and 64 (31.4%) the lowest dosages (< 50). Of 158 patients persevering with treatment long enough to judge the outcome thereof, 107 (67.7%) achieved tolerance, 12 (7.6%) had a partial response, while 39 (24.7%) did not respond. Multivariate logistic regression analysis showed that two variables were independently associated with the highest probability of success: the use of high dose protocols (> or = 100 IU/kg/day) (p < .0001) and the presence of low levels of inhibitor (< 10 BU) at enrollment (p = .004). The Kaplan-Meier inhibitor-free survival curve showed that tolerance is longlasting: only 1 out of 107 patients relapsed and the longest documented tolerant patient has been inhibitor-free for 16 years. 129 hemophiliacs were HIV Ab-negative at enrollment; of the 118 HIV-screened after the treatment, 18 (13.9%) were found to be HIV Ab-positive. IT can indeed modify the natural history of inhibitors to FVIII in hemophilia.

Adolescent↗
PubMed1994

Immunopurified clotting factor concentrates.

Monoclonally purified factor concentrates have been available for hemophilia treatment since the late 1980's. They are biochemically characterized by a high-degree of clotting factor (FVIII or FIX) purification and by the virtual lack of contaminants (immunoglobulins, fibrinogen and fibronectin). The purification procedure sharply reduces the viral load and increases the safety of the concentrate because of the viral inactivation procedures. Viral safety is demonstrated by prospective studies in previously untreated patients as well as by the huge amount of concentrates produced and used so far without reports of untoward side effects. Monoclonal concentrates are also safe in terms of inhibitor production: they do not elicit the appearance of inhibitors to either FVIII or FIX with increased frequency, as shown by data in published prospective studies. Prospective studies have recently demonstrated that the long-term administration of these high purity concentrates does not exert any side effects on the immune system in HIV-positive hemophiliacs. The FIX concentrate is also extremely safe in terms of thrombotic complications: the highly pure FIX does not activate blood coagulation. It has been shown that the monoclonally purified FIX concentrate caused no thrombotic events in high-risk surgical patients who had previously experienced such complications while on Prothrombin Complex Concentrates.

Antibodies, Monoclonal↗