Search PubMed⌕ Search

Biomedical subjects

S Rizzo

Publications and source records attributed to S Rizzo.

At least 37 records · Page 2Linked to original sources
PubMed2000

3,3'-Bis(diphenylphosphino)-1,1'-disubstituted-2,2'-biindoles: easily accessible, electron-rich, chiral diphosphine ligands for homogeneous enantioselective hydrogenation of oxoesters

Racemic (+/-)-3,3'-bis(diphenylphosphinyl)-1,1'-dimethyl-2, 2'-biindole (1c) (N-Me-2-BINPO) and (+/-)-3, 3'-bis(diphenylphosphinyl)-1,1'-bis(methoxymethyl)-2,2'-biindole (1d) (N-MOM-2-BINPO) were synthesized in satisfactory yields following a three-step reaction sequence, starting from indole. Resolution of racemic 1c and 1d was achieved through fractional crystallization of their diastereomeric adducts with optically active dibenzoyl tartaric acids, followed by alkaline decomplexation of the diastereomerically pure salts. Their trichlorosilane reduction gave enantiopure phosphines (+)- and (-)-(1a) (N-Me-2-BINP) and (+)- and (-)-(1b) (N-MOM-2-BINP). The electrochemical oxidative potential of 1a and 1b was found to be 0. 52 and 0.60 V, respectively. Both the enantiomers of (1a) were tested as ligands of Ru(II) in asymmetric hydrogenation reactions of alpha- and beta-oxoesters. Reactions were found to be outstandingly fast and enantioselection quite good. Comparative kinetic experiments on the hydrogenation reaction of methyl acetoacetate carried out with 1a, 1c, BINAP, and other biheteroaromatic diphosphines as ligands of Ru(II) demonstrated that all the reactions follow a first-order kinetic. A linear relationship was found between the kinetic constant log and the electrochemical oxidative potential of the diphosphine ligand.

Journal Article↗
PubMed2000

Assessment of bone marrow stem cell reserve and function and stromal cell function in patients with autoimmune cytopenias.

To investigate whether bone marrow (BM) stem cell compartment and/or BM microenvironment are affected by the immune insult in autoimmune cytopenias (AICs), BM stem cell reserve and function and BM stromal function were studied in 15 AIC patients. Stem cells were evaluated by means of flow cytometry, clonogenic progenitor cell assays, long-term BM cultures (LTBMCs), and limiting dilution assay for quantification of long-term-culture initiating cells (LTC-ICs). Stromal cell function was assessed with the use of preformed irradiated LTBMCs from patients and normal controls, recharged with normal CD34(+) cells. AIC patients exhibited a high number of CD34(+), CD34(+)/CD38(+), and CD34(+)/CD38(-) cells; high frequency of granulocyte-macrophage colony forming units in the BM mononuclear cell fraction; high colony recovery in LTBMCs; and normal LTC-IC frequency. Patient BM stromal layers displayed normal hematopoietic-supporting capacity and increased production of granulocyte-colony stimulating factor. Data from this study support the concept that AIC patients with severe, resistant disease might be appropriate candidates for autologous stem cell transplantation.

ADP-ribosyl Cyclase↗
PubMed2000

Glucocorticoids promote the proliferation and antagonize the retinoic acid-mediated growth suppression of Epstein-Barr virus-immortalized B lymphocytes.

Glucocorticoids are able to release Epstein-Barr virus-immortalized (EBV-immortalized) lymphoblastoid B cell lines (LCLs) from the persistent growth arrest induced in these cells by retinoic acid (RA). Moreover, physiologic concentrations of glucocorticoids efficiently antagonized LCL growth inhibition induced by 13-cis-RA; 9-cis-RA; all-trans-RA; and Ro 40-6055, an RA alpha receptor (RAR alpha) selective agonist. RAR alpha expression levels, however, were not affected by glucocorticoids. Glucocorticoids, but not other steroid hormones, directly promote LCL proliferation, a phenomenon that was mainly mediated by down-regulation of the cyclin-dependent kinase (CDK) inhibitor p27(Kip-1). Moreover, glucocorticoids contrasted the up-regulation of p27(Kip-1), which was underlying the RA-induced LCL growth arrest, thereby indicating that glucocorticoids and RA signalings probably converge on p27(Kip-1). Both antagonism of RA-mediated growth inhibition and promotion of LCL proliferation were efficiently reversed by the glucocorticoid receptor (GR) antagonist RU486, indicating that all of these effects were mediated by GR. Of note, RU486 also proved to be effective in vivo and, in mice, was able to significantly inhibit the growth of untreated LCLs as well as LCLs growth-arrested by RA in vitro. These findings provide a rational background to further evaluate the possible role of glucocorticoids in the pathogenesis of EBV-related lymphoproliferations of immunosuppressed patients. Moreover, GR antagonists deserve further consideration for their possible efficacy in the management of these disorders, and the use of schedules, including both RA and a GR antagonist, may allow a more thorough evaluation of the therapeutic potential of RA in this setting. (Blood. 2000;96:711-718)

Animals↗
PubMed2000

Retinoic acid induces persistent, RARalpha-mediated anti-proliferative responses in Epstein-Barr virus-immortalized b lymphoblasts carrying an activated C-MYC oncogene but not in Burkitt's lymphoma cell lines.

We have previously demonstrated that 13-cis-retinoic acid (RA), 9-cis-RA and all-trans-RA (ATRA) powerfully inhibit the proliferation of Epstein-Barr virus-immortalized B-lymphoblastoid cell lines (LCLs). The aim of the present study was to assess whether these compounds are effective at inhibiting the growth of B cells at more advanced stages of lymphomagenesis, including fully transformed B lymphocytes. To this end, c-myc-transfected LCLs (myc-LCLs) and Burkitt's lymphoma (BL) cell lines were used. We report that 13-cis-RA, 9-cis-RA and ATRA also markedly inhibit the proliferation of myc-LCLs by inducing G(0)/G(1) growth arrest as well as enhancing rates of apoptosis. Conversely, all but 1 (DG75) of the 8 BL cell lines investigated were poorly RA-responsive. Moreover, unlike LCLs and myc-LCLs, RA-treated DG75 cells rapidly resumed proliferation upon drug removal. Analysis of cell cycle-regulatory proteins showed that, as in LCLs, strong up-regulation of p27(Kip-1) and increased levels of under-phosphorylated pRb and p130 were detected in RA-treated DG75 cells. While the catalytic activity of all 3 G(1)-associated CDKs (CDK2, CDK4 and CDK6) was strongly inhibited in RA-treated LCLs, only CDK2-associated kinase activity was reduced in DG75 cells arrested in G(0)/G(1) by RA. Moreover, RA-treated DG75 cells failed to show the down-regulation of cyclin D3 observed in LCLs. Use of receptor-selective agonists and antagonists showed that in LCLs and RA-responsive BL cells, RA-induced growth arrest is mainly mediated by RARalpha. The RARalpha-selective agonist Ro 40-6055 was also effective at very low concentrations (10(-10) M). Nevertheless, comparable levels of RARalpha mRNA were found in RA-responsive and -resistant BL cell lines, indicating that mechanisms different from transcriptional deregulation of RARalpha probably underlie the differential responsiveness of BL cells.

Antineoplastic Agents↗
PubMed2000

Reasons for use of hormone replacement therapy in women undergoing coronary angiography.

The recommendation has been made that all women be counseled about the risks and benefits of hormone replacement therapy (HRT). Use of HRT among women undergoing coronary angiography was explored to assess whether patterns of use were similar to data drawn from community samples. Using a descriptive design, a convenience sample of 414 postmenopausal women was interviewed. Fifty-eight percent had never used HRT, 18.3% were past users, and 23.7% were currently using HRT. The primary reason given for ever using HRT was for symptoms of menopause. Less than 14% of women cited coronary heart disease (CHD) or osteoporosis as their primary reason for using HRT. The most common reasons for stopping HRT were side effects and fear of cancer. The most common reasons given for never having used HRT were that their healthcare provider had never talked about it and that they had never thought about it. Use of HRT among women undergoing coronary angiography is similar to that found in community samples. The challenge is to promote patient-provider interactions that include information about HRT based on the scientific model as well as attention to women's individual concerns.

Adult↗
PubMed2000

[Inflammatory pseudotumor of the lung. Diagnostic-therapeutic effectiveness of its radical resection].

Clinical, therapeutical observations and experience in 3 cases of pulmonary inflammatory pseudotumors (PIP) are presented. A retrospective analysis is made of cases with pulmonary "mass" suspected as malignant tumor, resected in a general surgery department between 1988 and 1995, and finally diagnosed as inflammatory pseudotumor. Three of the 10 cases originally diagnosed as malignant lung tumor were inflammatory pseudotumor (30%). Pulmonary inflammatory pseudotumors, may be a pitfall diagnosing a lung mass and implicate legal problems. Surgical resection leads to the final diagnosis in doubtful cases. A wide resection has a diagnostic aim and may preserve healthy parenchyma. Clinicians, pathologists and surgeons should accurately inform patients with doubtful diagnosis of pulmonary malignancy. Any decision should be kept altogether either choosing the simple observation or the timely surgical diagnostic and therapeutical approach.

Diagnosis, Differential↗
PubMed1999

Morphologic characteristics of initial lymphatics of the healthy and diseased human gingiva.

Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium.

Gingiva↗
PubMed1999

Biologically relevant phenotypic changes and enhanced growth properties induced in B lymphocytes by an EBV strain derived from a histologically aggressive Hodgkin's disease.

Epstein-Barr virus (EBV) isolates show a wide genomic heterogeneity, and a key issue is whether distinct strain variations may contribute to the development and/or malignancy of EBV-related disorders. Herein, we report on the virologic and biologic characterization of an EBV strain derived from a cyto-histologically aggressive EBV-related Hodgkin's disease (HD) (case HD-3) showing a high number of "anaplastic" Reed-Sternberg cells expressing markedly high levels of CD30, CD40 and LMP-1. The HD-3-derived EBV showed strong in vitro immortalizing properties, as suggested by the unusually high number of spontaneous lymphoblastoid cell lines (LCLs) obtained from the patient. Immunofluorescence and immuno-cytochemical analyses showed that HD-3 LCLs expressed significantly higher levels of CD23, CD30, CD38, CD39, CD40 and CD71 antigens and CD54 and CD58 adhesion molecules than B95.8 LCLs. In contrast, the expression of CD11a, CD24, CD95, bcl-2, LMP-1 and EBNA-2 was similar in both groups of LCLs. These phenotypic changes are consistent with the induction of a pronounced activation status and are not dependent on the cellular background, having been closely reproduced by the same virus in LCLs from an unrelated donor (DEN-HD-3 LCLs). HD-3 LCLs were able to grow in vitro at low serum concentrations (up to 0.1%) and were significantly more clonogenic in soft agarose than B95.8 LCLs. Moreover, although no evidence of tumor formation was observed in nude mice injected with B95.8 LCLs, all 5 spontaneous LCLs of patient HD-3 and the 2 DEN-HD-3 LCLs grew in transplanted animals as lymphoproliferations composed of EBER+, LMP-1+ cells. Our findings indicate that the biologic properties of the HD-3 EBV strain are significantly different from those of the B95.8 virus and may have contributed to the cytologic and histo-pathologic malignancy of this HD case. Moreover, molecular characterization of the HD-3 EBV genome identified a 63-bp deletion within the 3' end of the LMP-1 gene as a likely significant change that may be responsible, at least in part, for the biologically relevant phenotypic modifications and enhanced in vitro and in vivo growth potential induced in B lymphocytes by this virus strain.

Animals↗
PubMed1999

Reduced TGF-beta1 in patients with aplastic anaemia in vivo and in vitro.

Transforming growth factor beta (TGF-beta) 1 is a ubiquitous bifunctional cytokine implicated in the regulation of haemopoietic stem cells and bone marrow stromal cells. We analysed sera from 63 patients with aplastic anaemia and describe a significant reduction of TGF-beta1 that was directly related to their treatment status. Untreated patients (n = 35), patients who did not respond (n = 15) and those with a partial response (n = 23) to treatment had significantly lower TGF-beta1 than the normal control group (n = 55), P < 0.0001, P < 0.0001 and P = 0.002 respectively. Patients in complete remission (n = 15) exhibited TGF-beta1 serum levels comparable to the control group. In addition, there was a correlation (r = 0.83, P < 0.0001) between serum TGF-beta1 and platelet count at time of sample. We have demonstrated that the primary source of TGF-beta1 in peripheral blood mononuclear cell (PBMC) cultures was not CD3-positive cells. These data indicate aplastic anaemia is associated with a decreased TGF-beta1 expression in peripheral blood circulation, which may be a direct consequence of thrombocytopenia. In vitro stromal layers grown from aplastic patient bone marrow (n = 14) produced significantly lower levels of TGF-beta1 (P = 0.02) when compared to normal stroma (n = 15). In the aplastic anaemia bone marrow compartment we postulate that accessory cells down-regulate TGF-beta1 expression to allow stem cell cycling to counteract hypoplasia. As TGF-beta1 is important in the regulation of haemopoiesis, dysregulation of this cytokine in combination with previously described abnormal cytokine expression may contribute significantly to the pathophysiology of aplastic anaemia by exacerbating primary stem cell defects.

Adolescent↗
PubMed1998

Retinoic acid-mediated growth arrest of EBV-immortalized B lymphocytes is associated with multiple changes in G1 regulatory proteins: p27Kip1 up-regulation is a relevant early event.

EBV-immortalized lymphoblastoid B cell lines (LCLs) are a suitable in vitro model for the study of EBV-related lymphoproliferative disorders of immunosuppressed patients. We have previously shown that 9-cis-, 13-cis- and all-trans-retinoic acid (RA) powerfully inhibit LCL proliferation at concentrations corresponding to therapeutically achievable plasma levels (10(-6) M). Herein we show that RA-induced LCL accumulation in the G0/G1 phases correlated with the loss of the catalytic activity of all three G1-associated CDKs (CDK2, CDK4 and CDK6) and with increased levels of underphosphorylated pRb and, in some LCLs, p130. LCLs arrested in G0/G1 by RA also showed a significant decrease in the protein levels of cyclins D2, D3 and A, together with a reduction in the amount of cyclin D associated with CDK4 and CDK6, probably accounting for the inhibition of the relative kinase activity. In addition, RA-treated LCLs showed a marked up-regulation of the CDK inhibitor (CKI) p27Kip-1 at the protein but not mRNA level, which correlated with a progressive increase of p27Kip-1 in CDK2 complexes (more than 2.5-fold) and with a reduction in the active phosphorylated form of CDK2. p27Kip-1 may also contribute to the inhibition of CDK4 kinase activity, as the amount of CDK4-associated p27Kip-1 was increased by 50% after RA exposure. p27Kip-1 up-regulation stably persisted for more than one week after RA withdrawal concomitantly with the maintenance of the proliferative block. Moreover, neutralization of TGFbeta did not affect the growth inhibitory activity of RA, suggesting that LCL growth arrest induced by these retinoids is probably not mediated by a pathway directly involving TGFbeta. Overall, these results demonstrate that RA treatment of EBV-immortalized B lymphocytes is associated with multiple effects on G1 regulatory proteins, including p27Kip1 up-regulation, decreased levels of cyclins D2, D3 and A, and inhibition of CDK2, CDK4 and CDK6 activity, which ultimately result in reduced pRb phosphorylation and G0/G1 growth arrest.

B-Lymphocytes↗
PubMed1998

Progressive telomere shortening in aplastic anemia.

Improved survival in aplastic anemia (AA) has shown a high incidence of late clonal marrow disorders. To investigate whether accelerated senescence of hematopoietic stem cells might underlie the pathophysiology of myelodysplasia (MDS) or paroxysmal nocturnal hemoglobinuria (PNH) occurring as a late complication of AA, we studied mean telomere length (TRF) in peripheral blood leukocytes from 79 patients with AA, Fanconi anemia, or PNH in comparison with normal controls. TRF lengths in the patient group were significantly shorter for age than normals (P < .0001). Telomere shortening was apparent in both granulocyte and mononuclear cell fractions, suggesting loss at the level of the hematopoietic stem cell. In patients with acquired AA with persistent cytopenias (n = 40), there was significant correlation between telomere loss and disease duration (r = -.685; P < .0001), equivalent to progressive telomere erosion at 216 bp/yr, in addition to the normal age-related loss. In patients who had achieved normal full blood counts (n = 20), the rate of telomere loss had apparently stabilised. There was no apparent association between telomere loss and secondary PNH (n = 13). However, of the 5 patients in the study with TRF less than 5.0 kb, 3 had acquired cytogenetic abnormalities, suggesting that telomere erosion may be relevant to the pathogenesis of MDS in aplastic anemia.

Adolescent↗
PubMed1998

Sensitivity and specificity of ultrasonography, fluorescein videoangiography, indocyanine green videoangiography, magnetic resonance and radioimmunoscintigraphy in the diagnosis of primary choroidal malignant melanoma.

The prognosis of primary choroidal malignant melanoma (PCMM) is fatal if no early reliable diagnosis is performed. Any incisional biopsy is impossible, and diagnosis is only based on instrumental examinations. The purpose of this study is to evaluate the reliability of ultrasonography, fluorescein videoangiography (FV), indocyanine green videoangiography (ICGV), magnetic resonance (MR) and radioimmunoscintigraphy (RIS) in the diagnosis of PCMM in a series of 12 eyes in which the tumor was suspected. A presumed diagnosis of PCMM was made when a positive result was obtained with 3 or more methods. The presumed diagnosis was then compared with histological findings (true value) in 4 enucleated eyes. The sensitivity and specificity of every single method were evaluated comparing its results with the final presumed diagnosis and with the histological findings. Sensitivity and specificity of every single method have been expressed as percentage of correspondence with the presumed diagnosis. Sensitivity was 100% for ultrasonography, MR, FV, ICGV and 67% for RIS. Specificity was 92% for ultrasonography, 87% for RIS, 83% for MR and 82% for FV and ICGV. This study indicates that the ophthalmologist can obtain a good diagnostic reliability in the case of PCMM using only ultrasonography, FV and ICGV. Besides MR and RIS are important adjunctive methods to ophthalmological investigations for the diagnosis of PCMM.

Aged↗
PubMed1998

Ultrasonographic and angiographic follow-up of primary choroidal malignant melanoma after proton beam irradiation therapy.

The aim of this study is to evaluate the reliability of the ultrasonographic and angiographic follow-up of primary choroidal malignant melanoma (PCMM) after proton beam irradiation therapy in a series of 14 patients. All patients underwent standardized A and B scan ultrasonography, fluorescein and indocyanine green videoangiography (FV, ICGV) before and after treatment with proton beam irradiation. The follow-up was carried out at 1, 3, 5, 8 months and then every 6 months. The mean follow-up was 26 months (range 6-46 months). The thickness of the tumors was demonstrated to be decreased and the internal reflectivity to be enhanced in 12 out of 14 cases from 8 months after treatment till the end of the follow-up period. In 2 eyes which were enucleated 5 months after treatment, histopathology confirmed that medium-low internal reflectivity corresponded to several areas of high cellularity and cellular mitosis. FV and ICGV were impossible because of opacities of dioptric media in 2 cases. From 8 months after treatment till the end of the follow-up period, in all the examined patients, FV demonstrated large hypofluorescent zones of the lesions which represented the destruction of the vascular tree of the tumor. From 8 months after treatment till the end of the follow-up period, ICGV demonstrated hypofluorescence of the lesions in 8 cases; mild hyperfluorescence and zones of colorant staining were present in late angiograms in 2 cases. The results of our study seem to confirm the reliability of standardized A and B scan ultrasonography in the follow-up of PCMM treated with proton beam irradiation; if ultrasonography is used together with FV and ICGV, the reliability of this combination is surely higher.

Aged↗
PubMed1998

Ultrasonographic follow-up of primary choroidal malignant melanoma after proton beam irradiation therapy.

The aim of this study is to evaluate the ultrasonographic aspects of primary choroidal malignant melanoma (PCMM) after proton beam irradiation therapy and the reliability of its ultrasonographic follow-up in a series of 10 patients. All patients were examined with standardized A and B scan ultrasonography before and after treatment with proton beam irradiation therapy. The follow-up was carried out at 1, 3, 5, 8 months and then every 6 months. The mean follow-up was 20 months (range 6-34 months). The thickness of the tumors was demonstrated to be decreased and the internal reflectivity to be enhanced in 9 out of 10 cases from 8 months after treatment till the end of the follow-up period. Histopathology confirmed in 1 eye enucleated 5 months after treatment that medium-low internal reflectivity coresponded with several areas of high cellularity and cellular mitosis. The results of our study indicate the reliability of standardized A and B scan echography in the follow-up of PCMM treated with proton beam irradiation therapy.

Aged↗
PubMed1998

Echographic study of the vitreoretinal interface in giant retinal tears.

Vitreous and vitreoretinal interface changes were evaluated in giant retinal tears in order to plan surgical approach. Vitreal sineresis was evident in patients affected by primary giant retinal tears; in patients affected by retinal disinsertion the vitreous was adherent to the edge of the posterior flap, and in giant retinal tears secondary to IOL implantation, posterior vitreous detachment but no sineresis was displayed.

Adult↗
PubMed1998

Reliability of standardized echography before vitreoretinal surgery for proliferative diabetic retinopathy.

Standardized A- and B-scan echography was performed in 45 patients (68 eyes) affected by proliferative diabetic retinopathy, before vitreoretinal surgery, to evaluate the percentage of agreement between the ultrasonographic data and the surgical findings. The agreement was quite good for tractional retinal detachment (93%) and for posterior vitreous detachment (91%). The main cause of failure was the presence of vitreoschisis, while preretinal and vitreal membranes can easily be detected.

Adult↗