Biomedical subjects
Publications and source records attributed to L Santi.
We report the stopping power of molecular hydrogen for antiprotons of kinetic energy above the maximum (approximately 100 keV) with the purpose of comparing with the proton one. Our result is consistent with a positive difference in antiproton-proton stopping powers above approximately 250 keV and with a maximum difference between the stopping powers of 21%+/-3% at around 600 keV.
Gene transfer delivery of endogenous angiogenesis inhibitors such as angiostatin would circumvent problems associated with long-term administration of proteins. Kaposi's sarcoma (KS), a highly vascular neoplasm, is an excellent model for studying tumor angiogenesis and antiangiogenic agent efficacy. We investigated the effects of angiostatin gene transfer in in vitro and in vivo models of KS-induced neovascularization and tumor growth. A eukaryotic expression plasmid and a Moloney leukemia virus-based retroviral vector for expression of murine angiostatin were generated harboring the angiostatin cDNA with cleavable leader signals under the control of either the strong cytomegalovirus promoter/enhancer or the Moloney leukemia virus long terminal repeat. Angiostatin secretion was confirmed by radioimmunoprecipitation and Western blot analysis. Supernatants of angiostatin-transfected cells inhibited endothelial cell migration in vitro. Stable gene transfer of the angiostatin cDNA by retroviral vectors in KS-IMM cells resulted in sustained angiostatin expression and delayed tumor growth in nude mice, which was associated with reduced vascularization. These findings suggest that gene therapy with angiostatin might be useful for treatment of KS and possibly other highly angiogenic tumors.
This paper describes two-hybrid interactions amongst barley homeodomain proteins encoded by the Three Amino acid Loop Extension (TALE) superfamily. The class I KNOX protein BKN3 is shown to homodimerise and to associate with proteins encoded by the class I and II Knox genes BKn-1 and BKn-7. Furthermore, JUBEL1 and JUBEL2, two BELL1 homologous proteins, are identified and characterised as interacting partners of BKN3. Differences in the requirements of BKN3 derivatives for interactions with KNOX and JUBEL proteins imply the involvement of overlapping but slightly different domains. This set of results is an example for interactions amongst different classes of plant TALE homeodomain proteins, as previously described for related animal proteins. Apparently identical spatial and temporal expression patterns of BKn-1, BKn-3, BKn-7, JuBel1 and JuBel2, as determined by in situ hybridisation, are compatible with possible interactions of their protein products in planta. Contradictory to the common model, that the transcriptional down-regulation of certain class 1 Knox-genes is the prerequisite for organ differentiation, transcripts of all five genes were, similar to Tkn1 and Tkn2/LeT6 of tomato, detected in incipient and immature leaves as well as in meristematic tissues. A characteristic phenotype is induced by the overexpression of JuBel2 in transgenic tobacco plants.
A pilot study has been carried out to evaluate women's compliance to a screening program for cervical cancer. The study, initiated in 1994, was performed in conjunction with the ACRO project of the CNR by the Italian National Health Institute, in collaboration with La Sapienza University of Rome and the National Institute for Cancer Research in Genoa. A preliminary telephone survey was carried out on a sample of 400 women (200 in Rome and 200 in Genoa) to assess, among other factors, their attitude towards the screening program. Afterwards, an ad hoc advertising campaign was launched and 21,827 women, randomly chosen from the register office's lists, were sent a personal invitation to participate in the screening. Most women showed interest in attending the screening program at the interview, but the percentages of participation were low (25.7% in Genoa and 27.3% in Rome). On the other hand, a high percentage of women who participated in the screening had already had a Pap test in the previous three years (Genoa, 73%; Rome, 76%). The recruiting techniques that were used in this study, and that are commonly used, do not seem to reach the core of the target population for cervical screening, i.e. women who have never had a Pap test or who had a Pap test more than 5 years earlier. New methods of recruiting aimed at categories at risk and based more on direct contacts need to be developed.
Explore the source record for details and available documents.
Interleukin (IL)-15 shares immuno-stimulatory properties with IL-2 and is a potent inducer of natural killer (NK) cell function. The major histocompatibility complex (MHC) class I-negative human small cell lung cancer (SCLC) cell line N592, engineered to express a modified IL-15 cDNA (N592/IL-15), secreted biologically active IL-15 (300-500 pg/ml), capable of boosting T-cell proliferation and NK activity 'in vitro'. The effect of IL-15 gene transfer on natural immunity 'in vivo' was assessed by xenotransplants in nude mice and compared with that of the IL-2 gene. N592 cells engineered with IL-2 (N592/IL-2) were promptly rejected, while N592/IL-15 displayed a significant delay in tumour growth and a slightly reduced take rate. However, in NK-depleted nude mice, N592/IL-15 displayed the same growth kinetics as unmodified N592 cells, and N592/IL-2 grew with slightly reduced kinetics. An impressive reactive cell infiltration, consisting mainly of macrophages and granulocytes, was associated with N592/IL-2 tumour rejection, while a more evident recruitment of NK cells was found in N592/IL-15 tumours. In both N592 transfected tumours, we found expression of chemoattractant molecules, such as granulocyte macrophage-colony stimulating factor (GM-CSF) and monocyte chemoattractant protein (MCP)-1, while macrophage inflammatory protein (MIP)-2 was produced by endothelial cells only in N592/IL-2 tumours. In this tumour, very few and severely damaged microvessels were found, while microvessels were numerous in N592/IL-15 tumours. The potent recruitment of NK cells mediated by IL-15 gene transfer suggests its possible therapeutic use in tumours lacking MHC class I.
Metastasis is a sequence of events including proliferation, migration, adhesion, invasion and subsequent metastatic growth of tumour cells in distant organs. We previously showed that highly metastatic variants of murine melanoma cells express higher levels of the basement membrane proteoglycan perlecan than low or non metastatic variants and expression of an antisense perlecan can reduce metastatic potential. In contrast, antisense expression of perlecan in fibrosarcoma cells was reported to enhance tumorigenesis. To better understand the role of perlecan in angiogenesis we have transfected KS-IMM, an immortalized cell line derived from a human Kaposi s sarcoma, with an antisense perlecan construct and investigated the positive/negative role of perlecan in KS. KS-IMM cells were transfected with either empty vector (neo) or the antisense perlecan construct and clones were isolated. Immuno-blot analysis showed a reduction of perlecan levels in two (AP3 and AP4) isolated clones, in Northern blot analysis endogenous perlecan was undetectable in the AP3 and AP4 clones, while it was present in the neo control clones. AP clones had a reduced migration to HGF in Boyden chambers as compared to neo clones. Proliferation in low serum or serum-free conditions was strongly reduced in the AP clones as compared to the neo control cells. The neotransfected cells showed rapid proliferation in low serum supplemented with HGF and VEGF, while antisense transfected clones showed little response. Finally, AP-trasfected KS-IMM cells had significantly reduced migration to VEGF and HGF with respect to controls. In contrast, when the AP transfected cells were injected in nude mice they paradoxically showed enhanced tumor growth as compared to controls. Our preliminary data indicate that perlecan reduction plays a crucial role on Kaposi s sarcoma cell migration and proliferation in vitro. However, in vivo KS-IMM depleted of perlecan had a growth advantage. A possible hypothesis is that perlecan is necessary for growth of KS-IMM cells in vitro, however its down-regulation might promote angiogenesis through increased angiogenic growth factor diffusion, resulting in enhanced tumor growth in vivo.
We describe the development of transnasal endoscopic approaches to the cranial base in an interdisciplinary series of 103 patients, including 13 in the pediatric age group. Our aim was to define, with the aid of different case reports, the possibilities of endoscopic techniques in tumor resection, fistula repair, the treatment of mucoceles and meningoceles, and of combined intracranial and endoscopic approaches. The advantages of these minimally invasive approaches are panoramic visualization, rapidity and reduction of the cosmetic and functional disabilities in comparison with other conventional approaches, and a better capacity for identifying and developing key landmarks for surgery. On the other hand, endoscopic surgery requires an exsanguine operation field, technical improvements in instruments, and specific skills. Interdisciplinary collaboration in endoscopic approaches has proved useful in integrating experiences without overlap between fields, and in broadening possibilities: in our opinion endoscopic approaches will certainly be important in the future of cranial base surgery.
This report presents a case of arteriovenous malformation (AVM) in the region of the superior vermis and quadrigeminal plate, which was partially embolized using a endovascular technique and subsequently surgically excised. An occipital transtentorial approach was employed to excise the AVM, and the patient did well without neurological complications postoperatively. Comparing various surgical approaches, we believe the occipital transtentorial approach is the best for the AVM of this region.
We developed an in vivo gene therapy approach to characterize and optimize the anti-angiogenic activity of class I interferons (IFNs), using packaging cell lines producing an amphotropic LXSN-based retrovirus expressing either IFN-alpha1 (alpha1Am12), IFN-beta (betaAm12) murine cDNAs, or the vector alone (neoAm12). Pretreatment of endothelial-like Eahy926 cells in vitro with conditioned media (CM) from alpha1Am12 or betaAm12 cells for 48 hours significantly inhibited their migration and invasion as compared to neoAm12-CM-treated cells. betaAm12-CM also inhibited the formation of capillary-like structures on Matrigel by EAhy926 cells. In vivo, inclusion of the betaAm12 cells strongly inhibited, and alpha1Am12 partially inhibited, the angiogenic response in the Matrigel sponge model in both immune-competent and athymic nude mice. Electron microscopy showed a reduction of host cell infiltration in alpha1Am12- and betaAm12-containing sponges and reduction of invading tubular clefts of host cells as compared to controls. Finally, inoculation of either alpha1Am12 or betaAm12 cells (10%) along with a highly angiogenic Kaposi's sarcoma cell line (90%) resulted in a powerful reduction of tumor growth in nude mice in vivo, as did infection with the interferon-alpha-producing retroviruses. These data suggest that a gene therapy approach using class I interferons can effectively inhibit tumor angiogenesis and growth of vascular tumors.
Explore the source record for details and available documents.
A central role in tissue invasion is played by proteases that degrade extracellular matrices; in particular specific metalloproteases (MMPs) have been frequently correlated with the invasive potential of tumor cells and with the angiogenic process. MMPs are tightly regulated by molecules controlling their activation and by specific inhibitors of MMPs, known as the Tissue Inhibitors of MetalloProteases or TIMPs. Four TIMP family members are currently known. An imbalance between MMPs and TIMPs is linked to the degradation of the extracellular matrix associated with several physiologic and pathologic events including angiogenesis, invasion and metastasis. TIMPs are not only the 'guardians' of tissue degradation, they are able to control cell proliferation and cell survival as well. Given the critical role that TIMPs play, it is vital to know how the expression of TIMPs is controlled. Here we review the major biological properties and the molecular regulation of the TIMP expression.
This review highlights the current strategies being employed towards gene therapy of cancer. Conceptually, the most simple diseases to treat with gene therapy would be monogenic inherited diseases, such as hemophilia. However, the vast majority of current gene therapy trials are for treatment of cancer patients, due to the recognition of gene alterations in cancer and the critical need for improvement of cancer therapy. Gene-based therapies for cancer in clinical trials include strategies that involve immuno-therapy, induction of drug sensitivity in tumor cells or resistance to chemotherapy of critical host tissues, and compensation for oncosuppressor loss or ablation of oncogenes. Two broad approaches have been used to deliver DNA to cells, a series of viral vectors and the use of plasmid DNA vectors, which have different advantages with regard to efficiency of gene transfer, ease of production and safety. Examined objectively, many of the first studies in cancer gene therapy clinical trials have provided information of critical importance for the design of more efficient second-generation protocols. Gene therapy represents one of the most important developments in oncology, however, before this can be realized as standard treatment the technical problems of gene delivery and safety must be overcome. Here we focus on methods and strategies used to achieve cancer gene therapy and the current clinical trials.
The matrix metalloproteinase (MMP) inhibitor TIMP-2 has a high specificity for gelatinase A/MMP-2. An imbalance between gelatinase A and TIMP-2 in favor of enzymatic activity is linked to the degradation of the extracellular matrix (ECM) associated with several physiologic and pathologic events, including angiogenesis, invasion and metastasis. Since TIMPs are secreted molecules, they have the potential to be used for gene therapy of certain tumors. We transfected B16F10 murine melanoma cells, a highly invasive and metastatic cell line, with an expression vector harboring a cDNA encoding for human TIMP-2. The clones obtained were isolated and examined for TIMP-2 over-expression and changes in tumor cell phenotype. The amount of recombinant TIMP-2 produced correlated with a reduction in invasion. In an in vivo angiogenesis assay, TIMP-2-transfected clones showed reduced levels of blood vessel formation, and in vitro conditioned media from TIMP-2 transfectants showed diminished induction of endothelial cell migration and invasion. TIMP-2 over-expression limited tumor growth in vivo and neoangiogenesis when cells were injected subcutaneously in mice in the presence of Matrigel. However, TIMP-2 overexpressing clones were found to be more resistant to apoptosis than parental and control melanoma cells, while necrosis was increased. Our data confirm the role of TIMP-2 in the down-regulation of metastasis and angiogenesis but indicate a possible involvement in tumor cell survival.
In this paper, the current status of the Molecular Probe Data Base (http://www.biotech.ist.unige.it/interlab/ mpdb.html ) is briefly presented together with a short analysis of its activity during 1997. This has been performed by statistically evaluating the 'logs' of the Internet servers that are used for its distribution with reference to the geographical origin of the requests, the words that were utilized to carry out of the searches and the oligonucleotides that were retrieved. Planned enhancements of this database are also described. They include a revision of its data structure and, even more relevant, of its data management procedures.
Kaposi's sarcoma (KS) is a highly angiogenic lesion which frequently presents as an aggressive form in HIV-infected male patients. We have previously shown that the HIV-1 Tat protein induces endothelial cell migration and invasion in vitro and a rapid angiogenic response in vivo, suggesting that it acts as a cofactor in epidemic KS. In this study we tested beta interferon (IFN beta) and retinoic acid (RA) for the inhibition of Tat-induced angiogenesis using in vivo and in vitro models. IFN beta, at a concentration above 2500 U/ml, was an effective inhibitor of Tat-stimulated growth, migration and morphogenesis of an endothelial cell line in vitro and of angiogenesis in vivo. A strong reduction of properties associated with neovascularisation was induced by 10,000 U/ml. In vivo, RA alone was on ineffective inhibitor of angiogenesis, and in vitro gave only a limited inhibition of endothelial cell growth. However, 13-cis RA used in combination with IFN beta impressively potentiated its effects. A combination of lower doses of IFN beta (2500 U/ml) and 13-cis RA induced a virtually complete inhibition of the Tat-related angiogenic phenotype both in vivo and in vitro. The potentiation of the anti-angiogenic activity of IFN beta by 13-cis RA suggests that this combination could be a useful approach for the therapy of epidemic KS.
Molecular Probe Data Base contains detailed information on synthetic oligonucleotides with a sequence of up to 100 nucleotides. This database prevalently contains information related to human oligonucleotides used in diagnostics. Molecular Probe Data Base has been made available on-line through the Internet by means of Network Information Retrieval (NIR) tools since 1993. Two years ago, a collaboration with EMBL Data Library was also set up, so that the Molecular Probe Data Base has been integrated with other molecular biology data banks in the sphere of the SRS WWW network browser. In this paper, the most recent enhancements and the current status of the Molecular Probe Data Base are briefly presented.
The medical records of all women (297 cases) with breast cancer > or = 70 years of age, presenting at our Institute from January 1980 to December 1989, were reviewed. Data from 226 elderly women was compared to that from 100 stage-matched patients < 50 years of age, presenting during the same 10-year study interval. Conservative surgery was significantly more frequent in young patients (71.1%) compared to elderly women (26.1%) and radical mastectomy according to Halsted was undertaken in 34.3% of the elderly group compared to 8.9% of young patients (p < 0.001). Since 'incidental' diagnosis was significantly more frequent in the elderly group (59.9% versus 6.0%) (p < 0.001), primary care physicians may play an important role in the early diagnosis of breast cancer in the majority of elderly women.