PubMed Health⌕ Search

Biomedical subjects

S Del Vecchio

Publications and source records attributed to S Del Vecchio.

At least 55 records · Page 3Linked to original sources
PubMed1993

Cytosine arabinoside increases the binding of 125I-labelled epidermal growth factor and 125I-transferrin and enhances the in vitro targeting of human tumour cells with anti-(growth factor receptor) mAb.

We report that cytosine arabinoside (Ara-C), a cytosine analogue that at low doses causes phenotypical changes on human leukemia cells in vitro and in vivo, induces growth inhibition of oropharyngeal cancer KB and lung adenocarcinoma A549 cell lines. An increase in the number of epidermal growth factor and transferrin receptors (EGFR, TrfR) is induced by Ara-C on these cells. Maximal EGFR up-regulation occurs 96 h after the beginning of Ara-C exposure while maximal TrfR up-regulation is detected 24 h later. These effects occur without changes in the affinity of EGFR and TrfR for their ligands. Two classes of EGF-binding sites with a Kd of 0.055 nM and 2.3 nM respectively, and one class of transferrin-binding sites with a Kd of about 4 nM are detected on both untreated and Ara-C-treated KB cells. [3H]Thymidine uptake is clearly stimulated on KB cells by nanomolar concentrations of EGF and transferrin, whereas in Ara-C-treated cells [3H]thymidine uptake is not increased by EGF and transferrin under conditions where maximal EGFR and TrfR up-regulation occurs. The enhanced EGF and transferrin binding is paralleled by a twofold increase of in vitro targeting of Ara-C-treated KB and A549 cells with anti-EGFR 108.1 mAb and anti-TrfR OKT9 mAb. We propose that Ara-C could provide a new approach for the improvement of the therapeutic index of anti-EGFR and anti-TrfR immunoconjugates.

Adenocarcinoma↗
PubMed1993

Two alternative mRNAs coding for the angiogenic factor, placenta growth factor (PlGF), are transcribed from a single gene of chromosome 14.

We have previously reported on the identification of a cDNA (placenta growth factor, PlGF) coding for a novel angiogenic factor expressed in placental tissue that is similar to vascular permeability factor/vascular endothelial growth factor (VPF/VEGF). Biochemical and functional characterization of PlGF derived from transfected COS-1 cells revealed that it is a glycosylated dimeric secreted protein able to stimulate endothelial cell growth in vitro. Here, we report the isolation and characterization of the PlGF gene located on chromosome 14. At least two different mRNAs are produced from this single-copy gene in different cell lines and tissues. Sequence comparison of the polypeptides encoded by the two different isolated cDNAs indicates that they are identical except for the insertion of a highly basic 21 amino acid stretch at the carboxyl end of the protein. RNA expression analysis of several tissues, tumors and cell lines indicates differential distribution of the two PlGF mRNAs. Finally, preliminary results indicate that the PIGF gene has been conserved in evolution, since the human PlGF cDNA hybridizes to sequences present in the genomic DNA of Drosophila, Xenopus, chicken and mouse.

Alternative Splicing↗
PubMed1992

[Visual and motor functions in schizophrenic patients].

In the present work, visual and motor functions have been explored in 26 chronic schizophrenic patients, and 7 acute schizophrenic patients, compared with 26 normal controls, by means of the Bender-Gestalt Test. Parameters under consideration were: Form distortion, rotation, integration, perseveration, use of space, subtle motricity, score (global parameter), and time employed. As regards distortion and rotation there have been highly significant differences between chronic patients and control group. Among acute patients, it was observed that perseveration was also highly significant. Conversely, integration and use of space did not differ significantly among the three groups involved. The global score, resulting from all the above mentioned parameters showed important differences between both patient groups on the one hand, and control group on the other hand. Taking into account that patients were being administered neuroleptic drugs, it can safely be said, however, that the Bender-Gestalt Test allows to recognize alteration in perceptual closure consistent with a loss of the objective structure of perceived phenomena, in both chronic and acute patients.

Adult↗
PubMed1992

Pelvic radioiodine uptake in a rectal wall teratoma after thyroidectomy for papillary carcinoma.

A 30-yr-old woman with previously resected papillary thyroid carcinoma was found to have a pelvic lesion which concentrated radioiodine. By performing simultaneous 131I whole-body and 99mTc-methylene diphosphonate bone scans, we found the lesion to be in soft tissue between the sacrum and bladder. Radioiodine therapy was postponed so that the lesion, a benign teratoma of the rectal wall, could be surgically removed. Prior to laparotomy, the patient received a second tracer dose of 131I so that the lesion could be located at surgery with a hand-held gamma detector. A postoperative whole-body 131I scan confirmed that the lesion had been removed, thus reducing the absorbed radiation that would have been received by the ovaries during radioiodine therapy. Although the lesion contained both thyroid and gastric epithelium, accumulated 131I was limited to the area with thyroid follicles.

Adult↗
PubMed1991

Malignant melanoma of the nipple: a case studied with radiolabeled monoclonal antibody.

We describe a case of histologically confirmed malignant melanoma of the nipple. The rare occurrence of these lesions accounts for the relative lack of criteria for standard surgical treatment. After a conventional workup including mammography, chest X ray, bone scan, liver ultrasonography and cytologic smear of the lesion, we used specific radiolabeled monoclonal antibody and external photoscanning to differentiate melanoma from Paget's disease. The patient underwent wide local excision of the lesion and axillary node dissection, and tumor control is optimal since she has no evidence of disease after 5 years of follow-up.

Antibodies, Monoclonal↗
PubMed1991

Evaluation of therapeutic response using iodine-131-B72.3 monoclonal antibody in patients with ovarian carcinoma.

We used radiolabelled monoclonal antibodies (MoAbs) to prove disease persistence after treatment for ovarian carcinoma. Twelve patients with histologically confirmed ovarian carcinoma were studied. They received 5 mCi (1 mg) of iodine-131-B72.3 by intravenous injection before and after a complete course of chemotherapy. Images were obtained with a LFOV gamma camera 2 h after MoAb administration and daily up to 6 days. Before treatment 8 patients had a true positive scan. Questionable antibody uptake was observed in 2 patients while 1 had a true negative scan and 1 a false-negative examination. After treatment the therapeutic response was evaluated. Five patients had partial remission and antibody scan showed persistence of disease in all patients except 1. Four patients showed progression of the disease and 1 no change. The antibody scan was positive in 4 and questionable in 1. Two patients had complete remission and negative antibody scans. Computed tomography (CT) could not always discriminate postoperative fibrosis from tumour lesions, especially when the peritoneum was involved in the disease. High serum levels of tumour markers were constantly associated with the presence of tumour lesions, but normal values did not guarantee absence of disease. We conclude than the antibody scan is complementary to CT and serum tumor markers in the definition of therapeutic response.

Antibodies, Monoclonal↗
PubMed1991

Endobronchial administration of iodine-131 B72.3 monoclonal antibody in patients with lung cancer.

We tested the feasibility of endobronchial administration of radiolabelled monoclonal antibodies (MoAbs) and the biodistribution of the radiotracer. Ten patients with histological confirmed adenocarcinoma or squamous cell carcinoma were studied. Nine received 470 muCi (103 micrograms) of Iodine-131-B72.3, a monoclonal antibody reacting against TAG 72 antigen, while one patient received 502 muCi (291 micrograms) of 131I-4C4, an indifferent antibody used for comparison in a negative control study. The radiolabelled antibody was administered through a flexible fiberoptic bronchoscope and placed on the tumour mass under visual monitoring. Scans with a large field-of-view gamma-camera showed retention of 131I-B72.3 at the tumour site up to 6-9 days in six of eight patients. No other organs were visualized with the exception of faint activity in the gastrointestinal tract, bladder and thyroid. On the contrary, the indifferent antibody 131I-4C4 was not retained at the tumour site 6 days after MoAb administration, and more prominent activity was found in the gastrointestinal tract. In one patient the study was not technically adequate because of failure of the delivery system. The vascular compartment contained less than 3% of the administered dose. We conclude that endobronchial administration is a feasible technique and allows stable and specific targetting of bronchial tumours. Furthermore, the low activity found in the plasma and other organs suggests that this approach may be used to deliver therapeutic doses of MoAbs to lung cancers.

Adenocarcinoma↗
PubMed1991

Clinical studies with B72.3 in ovarian cancer and probe-guided tumor localization.

The present study reports the findings of radiolabeled monoclonal antibody (MoAb) application in the post-operative monitoring of patients with ovarian carcinoma. We studied 40 patients with histologically confirmed ovarian cancer using two radiolabeled MoAbs, 131I-B72.3 and 131I-OC125. Antibody scans showed that high uptake of radiolabeled MoAb was consistently associated with presence of disease confirmed by computed tomography, ultrasonography, clinical evolution and in a few cases by second look procedures. Computed tomography could not discriminate well between post-operative fibrosis and tumor lesion especially when localized in the peritoneum. We conclude that radiolabeled MoAbs, computed tomography and serum tumor markers are complementary in the postoperative monitoring of patients with ovarian carcinoma.

Antibodies, Monoclonal↗
PubMed1990

Toxicity, immunogenicity, and tumor radioimmunodetecting ability of two human monoclonal antibodies in patients with metastatic colorectal carcinoma.

Two human immunoglobulin M (IgM) monoclonal antibodies (MoAbs), 16.88 and 28A32, which react with cytoplasmic (28A32 and 16.88) or cell surface (28A32) determinants on human colon carcinoma cells, were administered intravenously to 26 patients with metastatic colorectal carcinoma to determine if they could localize to sites of metastatic disease, if they had any antitumor or toxic effects, and to determine whether they would elicit an antihuman MoAb response. Serial scans showed tumor uptake of radioisotope in 12 of 16 patients receiving 131I-labeled 28A32 and in nine of 12 patients receiving 131I-labeled 16.88. No antitumor effects were seen with either antibody. No antibody-related toxic effects were observed following administration of 16.88, but two patients developed localized urticarial reactions following injection with antibody 28A32. No patient developed an antibody response to 16.88. Anti-28A32 reactivity was found in five of 12 (42%) normal sera and in seven of 23 (30%) patients before receiving any antibody. Following administration of 28A32, a low titer (1:10 dilution) of anti-28A32 developed in four patients with no preexisting antibody, a decrease in the preexisting titer was seen in three other patients, the titer remained constant in one patient, and no anti-28A32 was ever detected in six patients. In most cases, anti-28A32 activity was lost at dilutions greater than 1:10 and did not appear to affect antibody half-life in the serum or whole body retention of the antibody. We conclude that these human IgM MoAbs are capable of localizing at sites of disease in vivo, are nontoxic, and are poorly immunogenic in humans. Further studies to determine the specificity of targeting and to improve the delivery of antibody to sites of tumor are indicated.

Antibodies, Monoclonal↗
PubMed1989

Local distribution and concentration of intravenously injected 131I-9.2.27 monoclonal antibody in human malignant melanoma.

Regional measurements of 131I-9.2.27 distribution in human melanoma tumors were obtained using quantitative autoradiography. Tumors were removed from patients 72-96 h after they had received an i.v. injection of 9.15 mCi (100 mg) of 131I-9.2.27. The autoradiographic images showed that the radioactivity reaching the tumor was heterogeneously distributed. Areas of relative high and low uptake were selected in each tumor. Regions of high activity contained from 51 to 1371 nCi/g, while areas with low uptake had radioactivity ranging from 12 to 487 nCi/g. The reliability of the autoradiographic measurements was demonstrated by the strong positive correlation with direct tissue sample counting (r = 0.994 P less than 0.001). Since comparative immunocytochemistry showed a homogeneous and diffuse staining of target antigen on viable tumor cells, variability of monoclonal antibody uptake within individual tumors was not primarily due to heterogeneity of antigen expression in these cases. However, antigen levels accounted for some of the variation from tumor to tumor. When immunoperoxidase staining was repeated on adjacent sections without the addition of 9.2.27, it confirmed the nonuniform distribution of monoclonal antibody found at autoradiography. Thus, quantitative autoradiography gives information about the distribution and the local concentration of radioactive antibody in tumors allowing calculation of the radiation dose delivered to small regions within tumors.

Adult↗
PubMed1989

Anti-murine antibody response to mouse monoclonal antibodies: clinical findings and implications.

Many patients given murine monoclonal antibody become immune to these proteins. Important factors in the development of immunity are (1) the patient's ability to become immune and (2) whether whole immunoglobulin or Fab fragment was used. Circulating anti-murine antibodies increase the murine antibody plasma clearance and the liver or spleen uptake while reducing tumor targeting. Clearance rates and radioassay measured levels of anti-murine antibodies are related to serum murine/anti-murine antibody complexes. Unlabeled murine antibody displaces radiolabeled antibody from these complexes.

Animals↗
PubMed1988

Measurement of local Mr 97,000 and 250,000 protein antigen concentration in sections of human melanoma tumor using in vitro quantitative autoradiography.

An assay method that uses 125I-labeled monoclonal antibody (MoAb) and in vitro quantitative autoradiography was developed to determine the local concentration of tumor-associated antigens in tissue sections. Human melanoma biopsy specimens were evaluated for the expression of the Mr 97,000 and 250,000 protein antigens using MoAb-96.5 and MoAb-9.2.27, respectively. Tissue sections were incubated in solutions of increasing concentration of 125I-labeled MoAb with or without an excess of unlabeled antibody. Quantitative autoradiography was performed on the sections and compared with 125I standards to determine tumor-bound radioactivity and calculate bound pmol of MoAb per g of tumor. The total binding, nonsaturable binding, and specific binding of 125I-labeled MoAb to tumor were then computed. Specific binding of MoAbs to tumor tissue was saturable in all antigen-positive tumors. The maximal concentration of specific binding of antibody to tissue (Bmax) represented the tissue antigen concentration. Estimates of the Ka of antigen/antibody binding were also made. The reliability of the measurements was confirmed by testing sections from mixtures of antigen-positive and antigen-negative cells.

Antibodies, Monoclonal↗