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Biomedical subjects

A Vacca

Publications and source records attributed to A Vacca.

At least 163 records · Page 9Linked to original sources
PubMed1994

Estrogen receptors: new perspectives in breast cancer management.

The imbalance between proliferative and differentiative estrogenic effect, caused by quantitative and qualitative alteration of the estrogen receptor (ER) expression, may play a determinant role in mammary neoplastic transformation. Our studies demonstrate that ER levels are significantly higher in human mammary neoplastic tissues when compared to perineoplastic tissues and that increased ER expression is associated with ER gene hypomethylation. During progressive multifactorial carcinogenesis, ER overexpression may represent an early step in neoplastic transformation. In fact, high levels of ER represent good markers of differentiation and can predict the likelihood of benefiting from anti-estrogen therapy. Nevertheless, about 35% of ER-positive breast cancers are resistant to endocrine therapy and 10% of ER-negative tumors behave as hormone-sensitive tumors. Recent studies on ER mRNA variants, which naturally occur in human breast tumors, demonstrated mutations, deletions and alternative splicings, yielding deletions of exons 3, 4, 5 and 7. ER variants exhibited altered functions or changed the responsiveness to hormonal therapy. Analysis of these variants could be a useful parameter to better predict tumor responsiveness to anti-estrogen therapy. Recently, a regain of hormonal responsiveness by ER-negative breast cancer cells has been reported following ER gene transfection. However, estradiol treatment inhibits rather than stimulates cell growth as well as the metastatic and invasive potential of the ER gene transduced cells. Transfer of the ER gene may be considered as a new therapeutic approach in the management of hormone-independent breast cancer.

Breast Neoplasms↗
PubMed1994

Bone marrow angiogenesis and progression in multiple myeloma.

Tumour growth is angiogenesis-dependent. We found a high correlation between the extent of bone marrow angiogenesis, evaluated as microvessel area, and the proliferating (S-phase) fraction of marrow plasma cells, evaluated as labelling index (LI), in patients with multiple myeloma (MM) and in those with monoclonal gammopathies of undetermined significance (MGUS). Angiogenesis itself was significantly associated with active as opposed to non-active MM and MGUS. The highest microvessel area accompanied rapidly progressive MM with the highest LI. When a cut-off value of 2% or greater of the microvessel area was used, most patients with active MM were classified correctly. The risk of active disease in patients with MM increased in parallel with the microvessel area. A causal relationship between plasma cell growth, activity phase in MM and marrow angiogenesis is suggested. Since angiogenesis proceeds in step with the enlargement of plasma cell tumours and the activity phase in MM, its measurement could be a useful prognostic marker in patients with plasma cell proliferative disorders.

Aged↗
PubMed1994

Identification of two different HLA B49 DR4 extended haplotypes in the Sardinian population.

The HLA-B49 DR4 haplotype, which is rare in Caucasoid populations, has a frequency in Sardinia of approximately 6% and a very strong linkage disequilibrium (LD). To better understand its genetic structure, the Bf, C4A and C4B Class III alleles were studied in 56 healthy unrelated Sardinian subjects of B49 DR4 phenotype and in 24 of their families. Moreover, 14 sick subjects with the same phenotype were examined together with five of their families. A group of 285 haplotypes belonging to randomly selected individuals was used as a control population sampling. The distribution of the Bf, C4A and C4B alleles among the healthy probands revealed two main groups of association: one major group of 36 subjects (64.3%) with the BfF, C4A3 and C4B4 alleles and one minor group of 14 subjects (25%) with BfS, C4AQ0 and C4B1. A similar subdivision was also observed in the small group of patients. The family analysis confirmed these results and showed two different B49 DR4 extended haplotypes: one with the F34 complotype in 79.1% of the probands (delta x 1000 = 49.0) and the other with the S01 complotype in 20.8% of the probands (delta x 1000 = 17.3). The first one, in LD with the A1 and Cw7 alleles, has not yet been reported in other populations. The second one seems to be identical to a haplotype already reported in the Spanish population. The molecular analysis of the DRB1 locus carried out in 20 of the 70 probands demonstrated that, in both haplotypes, DR4 was represented by the DRB1*0405 allele.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1994

Differential expression of two ICAM-1 epitopes and LFA-1 chains in B-cell non-Hodgkin's lymphomas.

B-cell non-Hodgkin's lymphomas (B-NHL) and B-cell areas of reactive lymphadenopathies were investigated immunohistochemically for expression of two distinct ICAM-1 epitopes, Me14/D12 and P3-58, and the LFA-1 alpha and beta chains. Partial or total loss of expression of one or both epitope(s) and/or chain(s) was evident in all B-NHL in function of increasing Working Formulation (WF) malignancy grade, with most defects in the high-grade tumors, namely the lowest detectability of the ICAM-1 Me14/D12 and LFA-1 alpha chain, the lowest co-expression of ICAM-1 epitopes and LFA-1 chains, and the most frequent simultaneous loss. The ICAM-1 and LFA-1 profiles overlapped within the low- and intermediate-grades, whereas striking differences between the high-grade subtypes were detected. Specifically, Burkitt's and lymphoblastic tumors always lost both epitopes and both chains. Large cell, immunoblastic tumors occasionally did so, and also showed either uncoordinated expression or co-expression of these constituents. It is suggested that expression defects of this type may help differentiate malignant from benign lymphoproliferations, and also be involved in the progression of B-NHL, since most are observed in high-grade tumors, whose ICAM-1 and LFA-1 profiles indicate that their subtypes are the expression of distinct normal B-cell differentiation stages.

Antibodies, Monoclonal↗
PubMed1994

Successful unrelated bone marrow transplantation in beta-thalassaemia.

A 16-year-old Sardinian girl affected by homozygous beta-thalassaemia was submitted to allogeneic BMT using an HLA-identical, MLC-negative, unrelated donor. The donor and the patient were homozygous for the entire extended haplotype A30, Cw5, B18, F130, DRB1*0301, DRB3*0202, DQA1*0501, DQB1*0201 and heterozygous for DPB1*0301/DPB1*0202. The conditioning regimen consisted of 14 mg/kg busulphan and 160 mg/kg cyclophosphamide. Engraftment was achieved 14 days from BMT and the haematological reconstitution was complete without any signs of acute or chronic GVHD. Seven months after the transplant the patient was in excellent general condition. The hypothesis is advanced that when two HLA extended haplotypes are shared by donors and recipients, particularly in homozygosity, this is a very favourable immunogenetic condition in unrelated BMT.

Adolescent↗
PubMed1993

Protective and curative potential of vaccination with interleukin-2-gene-transfected cells from a spontaneous mouse mammary adenocarcinoma.

The potential of interleukin 2-gene-transfected tumor cells to prevent tumor growth and cure established tumors was evaluated using cells from a spontaneous, invasive, and metastasizing mouse mammary adenocarcinoma. Tumor cells engineered to secrete interleukin 2 initially trigger a local inflammatory reaction that leads to inhibition of established parental adenocarcinomas, as well as an antigenically unrelated fibrosarcoma. The ensuing systemic immunity selectively inhibits subsequent parental cell challenges and cures established parental adenocarcinomas and their lung metastases, although less effectively as the neoplastic mass increases. Multiple injections of interleukin 2-gene-transfected tumor cells may thus be considered a new form of vaccination in the management of minimal residual disease and incipient metastases.

Adenocarcinoma↗
PubMed1993

Melanocyte tumor progression is associated with changes in angiogenesis and expression of the 67-kilodalton laminin receptor.

BACKGROUND: A number of experimental studies have substantiated changes in angiogenesis and in laminin/laminin-receptor interactions during tumorigenesis and tumor progression. However, these observations have never been verified objectively in tissues from a well-defined model of tumor progression. METHODS: Tissues from 97 proliferative lesions of the melanocyte lineage defining distinct steps in tumor progression were investigated immunohistochemically for changes in angiogenesis and expression of the laminin receptor (67-kilodalton molecule). RESULTS: Although the microvessel number was low in common nevi, it increased significantly in nevi with architectural disorder with varying degrees of melanocytic atypia (termed "nevi with ADMA"), and these changes persisted during transformation. Progression to primary melanomas was accompanied by a high microvessel number and progression to metastases by another significant increase. The number and diameter of microvessels were significantly higher at the lesion base than at the adjacent dermis of primary melanomas and higher in the lesion than in the adjacent tissue of metastatic foci. Expression of the laminin receptor, evaluated as percentages of positive lesions and positive cells per lesion, underwent upregulation in the course of progression. Changes in expression were associated mostly with nevi with ADMA, transformation, and deepening of the tumors into the dermis. CONCLUSIONS: These in situ data suggest that more frequent interactions between melanocytic cells and their microvasculature via adhesion protein laminin occur during tumor progression.

Adult↗
PubMed1993

Transcriptional regulation of interleukin-2 gene expression by CD69-generated signals.

The 5' flanking region of the human interleukin (IL)-2 gene was investigated for enhancer activity in response to CD69-generated signals, using a chloramphenicol acetyltransferase (CAT)-driven transient expression system in Jurkat cells. The region extending from -317 to +47 relative to the initiation site of IL-2 gene transcription was shown to contain sequences able to respond to CD69 cross-linking, by enhancing by about 100% a phorbol 12-myristate 13-acetate (PMA)-plus-ionomycin stimulation of CAT activity. A similar increase in CAT activity produced by PMA-plus-anti-CD3 mAb was induced by CD69 cross-linking, while a 200% increase over that obtained by PMA-plus-anti-CD28 mAb stimulation was seen. Analysis of enhancer deletion mutants revealed that proximal AP-1, OCT-1/octamer-associated protein and nuclear factor of activated T cells (NFAT) binding regions were all necessary to allow CD69-mediated enhancement of CAT activity. By gel mobility shift analysis, cyclosporin A-sensitive NFAT-binding induction and enhancement of AP-1 binding activity could be detected in nuclear extracts of both Jurkat and peripheral blood T cells after simultaneous CD69 and protein kinase C stimulation. Finally, CD69-mediated signals could increase NFAT and AP-1 binding activity following PMA and ionomycin stimulation in peripheral blood T cells. Collectively, these data suggest that CD69-generated signals participate in the control of the IL-2 gene expression at the transcriptional level, likely acting through NFAT and AP-1 transcription factor complexes.

Antigens, CD↗
PubMed1993

Association of the HLA-A2, CW2, B27, S31, DR2 haplotype with ankylosing spondylitis. A possible role of non-B27 factors in the disease.

With the aim of searching for HLA haplotypes and non-B27 allele frequency variations in Sardinian AS patients, HLA-A, B, Cw, DR, DQ and Bf, C4A and C4B typing and haplotype assignment was carried out in the families of 25 AS patients and in 44 healthy individuals, all B27 heterozygotes. In the AS patients a significant increase of the A2, Cw2, B27, DR2, DQ1 haplotype was found. This depends only partially on the linkage disequilibrium existing in the Sardinian population between B27 and the other alleles of this haplotype, and rather seems to be due to a primary association of Cw2 and DR2 alleles with AS. Preliminary data seem to show that this haplotype bears the S31 complotype and the DRB1*1601 allele both in the AS patients and in the healthy controls. The pathogenetic implications of these findings are discussed.

Adult↗
PubMed1993

Cell-specific bifunctional role of Jun oncogene family members on glucocorticoid receptor-dependent transcription.

Interaction between protein kinase C (PKC)- and glucocorticoid receptor (GR)-mediated signaling is suggested by the ability of the PKC activating phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to inhibit GR-dependent transcription of the mouse mammary tumor virus (MMTV) long terminal repeat (LTR). Here we report that this interference is cell specific, as TPA augmented dexamethasone-induced transcriptional activation of the MMTV LTR in several T cell lines but was inhibitory in NIH-3T3 fibroblasts. TPA-GR synergism was determined to have occurred at the GR-responsive element (GRE) level by functional analysis of deletion mutants or synthetic GRE oligonucleotides driving chloramphenicol acetyl-transferase expression. Synergism required an intact GR DNA-binding domain, whereas amino- or carboxyl-terminal domains were dispensable. The effect was abrogated by the PKC inhibitor staurosporine, suggesting a role for PKC. Increased c-jun, jun-B, and jun-D expression above basal levels and increased transcriptional activity of AP-1/TPA responsive elements fused to chloramphenicol acetyl-transferase vectors were observed in T cells treated with TPA alone or in combination with dexamethasone. The ability of Jun proteins to cooperate with GR in T cells has been investigated after transfection of c-jun, jun-B, or jun-D expression vectors, which augmented GR-dependent transcription from either MMTV LTR or GRE. Conversely, c-jun and jun-B transfection blunted GR-dependent transcription in HeLa cells. The presence of c-fos had a negative influence on GR function and correlated with the cell-specific synergistic or antagonistic activity of Jun with respect to GR; high basal expression of c-fos as well as AP-1 DNA binding and transcriptional activity were observed in HeLa cells, but not in T cells. Furthermore overexpression of exogenous c-fos has an inhibitory effect on GR-dependent transcription from GRE in T cells. We propose that Jun plays a bifunctional role on GR-dependent transcriptional activation of GRE, selecting either synergistic or antagonistic activity depending on the cell-specific microenvironment. In this regard, intracellular levels of c-fos appear to be influential.

3T3 Cells↗
PubMed1993

Allogeneic bone marrow transplantation combined with multiple anti-HIV-1 treatment in a case of AIDS.

A 25-year-old woman with AIDS was submitted to HLA-identical allogeneic BMT after cytoablation with busulphan and cyclophosphamide and combined anti-HIV-1 therapy with zidovudine, IFN-alpha 2 and anti-HIV-1-specific T cell clones. Marrow engraftment occurred after 18 days and tests for HIV-1 were negative after 30 days but the hematologic reconstitution of the patient was poor. A second BM infusion from the same donor was ineffective and treatment with GM-CSF only induced a transient increase of the blood cell count, suggesting iatrogenic damage to the BM microenvironment. The development of ARDS led to the death of the patient 10 months after transplantation. Post-mortem investigation did not reveal any active infections and PCR on autopsy tissues was negative for HIV-1.

Acquired Immunodeficiency Syndrome↗