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Biomedical subjects

S Ferrari

Publications and source records attributed to S Ferrari.

At least 127 records · Page 7Linked to original sources
PubMed1999

The lack of chromosomal protein Hmg1 does not disrupt cell growth but causes lethal hypoglycaemia in newborn mice.

High mobility group 1 (HMG1) protein is an abundant component of all mammalian nuclei, and related proteins exist in all eukaryotes. HMG1 binds linear DNA with moderate affinity and no sequence specificity, but bends the double helix significantly on binding through the minor groove. It binds with high affinity to DNA that is already sharply bent, such as linker DNA at the entry and exit of nucleosomes; thus, it is considered a structural protein of chromatin. HMG1 is also recruited to DNA by interactions with proteins required for basal and regulated transcriptions and V(D)J recombination. Here we generate mice harbouring deleted Hmg1. Hmg1-/- pups are born alive, but die within 24 hours due to hypoglycaemia. Hmg1-deficient mice survive for several days if given glucose parenterally, then waste away with pleiotropic defects (but no alteration in the immune repertoire). Cell lines lacking Hmg1 grow normally, but the activation of gene expression by the glucocorticoid receptor (GR, encoded by the gene Grl1) is impaired. Thus, Hmg1 is not essential for the overall organization of chromatin in the cell nucleus, but is critical for proper transcriptional control by specific transcription factors.

Animals↗
PubMed1999

Identification of cyclin A/Cdk2 phosphorylation sites in B-Myb.

B-myb is a highly conserved member of the myb proto-oncogene family that encodes a ubiquitously expressed 110-kDa sequence-specific DNA-binding protein. Transactivation of Myb-inducible promoters by B-Myb is repressed by a regulatory domain located at the C-terminus of the protein. Cyclin A/Cdk2-mediated phosphorylation apparently releases the negative constraint and triggers B-Myb transactivation potential. Two-dimensional tryptic phosphopeptide analysis indicated that the majority of the sites phosphorylated in vivo are targeted in vitro by cyclin A/Cdk2. Six sites in B-Myb fulfil the requirements for recognition by Cdk2. Using point mutation of the phosphorylation sites to nonphosphorylatable amino acids, we show that five of these sites are targets for Cdk2 in vivo. Mutation of one of these residues (T524) to alanine diminished the ability of B-Myb to promote transcription of a reporter gene, suggesting that phosphorylation of B-Myb at this site is important for the regulation of its activity by cyclin A/Cdk2.

Amino Acid Substitution↗
PubMed1999

Prospective evaluation of high-dose ifosfamide-related nephrotoxicity in young adult patients with recurrent osteosarcoma previously treated with cisplatin, methotrexate and standard-dose ifosfamide.

A prospective evaluation of high-dose ifosfamide (IFO)-related nephrotoxicity in adults and young adults previously treated with cisplatin, methotrexate (MTX) and standard-dose IFO was performed. Eighteen patients (median age 22) with recurrent osteosarcoma were studied: 11 were pretreated with MTX, cisplatin and standard-dose IFO, and seven with MTX and cisplatin. The treatment was comprised of four cycles of high-dose IFO (15 g/m2 over 5 days CI) and mesna at equivalent dose with granulocyte colony stimulating factor support. Renal function was assessed before treatment, after each IFO cycle and after chemotherapy completion. Acute nephrotubular damage was always observed after each IFO cycle with significant changes of renal tubular enzymes N-acetyl-beta-D-glucosaminidase, alanine aminipeptidase, urinary excretion and reduction of tubular reabsorption of phosphate. The appearance of glycosuria was related to the cumulative dose received. Transient and reversible renal tubular acidosis was observed in three patients. WHO grade I renal toxicity was observed in two patients. After chemotherapy completion, persistent mild glomerular and nephrotubular impairment was observed in one patient who had also received aminoglycoside antibiotics due to febrile neutropenia. Persistent and mild glycosuria was documented in another patient. No significant changes compared to baseline values were observed in the remaining patients. We conclude that a chemotherapy regimen with high-dose IFO in young adults pretreated with MTX, cisplatin and standard-dose IFO is feasible with a mild, usually reversible, nephrotoxicity.

Adolescent↗
PubMed1999

Genetic aspects of osteoporosis.

At a given age, bone mass represents the difference between the maximal amount of bone mineral mass gained during growth (peak bone mass) and post-menopausal and/or senile bone loss. Twins and parents-offspring models have shown a strong inheritance of peak bone mass and it is now known that familial resemblance in various bone mass constituents is detectable well before the pubertal growth spurt. Recent developments in the molecular epidemiology of osteoporosis have focused on the association between areal bone mineral density and common polymorphisms in several candidate genes. Among them, vitamin D receptor (VDR), estrogen receptor and collagen-1 -alpha-1 (COL1A1) genes have been the most extensively investigated. Although controversial results have been reported and osteoporosis cannot be predicted by any single polymorphic gene marker, recent advances in this field have emphasized the complexity of bone mineral mass determination, because of gene-gene and gene-environment interactions.

Bone Density↗
PubMed1999

The Drosophila polycomb protein interacts with nucleosomal core particles In vitro via its repression domain.

The proteins of the Polycomb group (PcG) are required for maintaining regulator genes, such as the homeotic selectors, stably and heritably repressed in appropriate developmental domains. It has been suggested that PcG proteins silence genes by creating higher-order chromatin structures at their chromosomal targets, thus preventing the interaction of components of the transcriptional machinery with their cis-regulatory elements. An unresolved issue is how higher order-structures are anchored at the chromatin base, the nucleosomal fiber. Here we show a direct biochemical interaction of a PcG protein-the Polycomb (PC) protein-with nucleosomal core particles in vitro. The main nucleosome-binding domain coincides with a region in the C-terminal part of PC previously identified as the repression domain. Our results suggest that PC, by binding to the core particle, recruits other PcG proteins to chromatin. This interaction could provide a key step in the establishment or regulation of higher-order chromatin structures.

Animals↗
PubMed1999

Determination of ifosfamide by HPLC using on-line sample preparation.

The Authors have developed a novel and easily applicable HPLC method for ifosfamide (IF) determination. This method involves on-line sample processing and its solid-phase extraction by means of an automatic preparator integrated with the chromatographic system. The calibration graph of the method is linear in the concentration range 6-200 microg/ml; minimum detectable concentration is 6 microg/ml. This highly accurate and easily reproducible method was used by the Authors in the treatment of osteosarcoma with slow infusion of ifosfamide.

Adolescent↗
PubMed1999

Cd 34+ cells and clonogenicity of peripheral blood stem cells during chemotherapy treatment in association with granulocyte colony stimulating factor in osteosarcoma.

The introduction of aggressive chemotherapy in the treatment of osteosarcoma has improved the long-term outcome for these patients. With the increasing aggressiveness of chemotherapy protocols, hematopoietic growth factors have emerged as useful adjuncts involving, in some cases, rescue by peripheral blood stem cell (PBSC) infusion to assist faster recovery and maintain relative dose intensity. To evaluate the number of PBSCs needed, we analyzed the number of CD34+ cells and hematopoietic progenitor cells in the peripheral blood of 16 patients with osteoblastic, condroblastic and fibroblastic osteosarcoma enrolled in an Istituto Ortopedico Rizzoli-Scandinavian Sarcoma Group (IOR-SSG) pilot study, consisting of two cycles of preoperative high dose chemotherapy. The blood samples were studied at different times. The CD34+ cells were analyzed by flow cytometry and the hematopoietic progenitor cells were analyzed by tissue culture clonogenic assay. In comparing the two courses of chemotherapy, we observed that modification of the mean values of WBC, CD34+ and CFU-GM were very similar. The second course of chemotherapy seemed to induce greater hematological toxicity. All three parameters showed good correlation. The results demonstrated that the best time to collect PBSC by means of leukapheresis is post G-CSF used as rescue after ifosfamide treatment. We verified the ability of G-CSF to mobilize PBSCs in patients with osteosarcoma through cytofluorimetric analysis of CD34+ cells and their clonogenic capability. Moreover, during this preoperative treatment, we identified the best time to collect a sufficient number of PBSCs, that is after 9-10 days of G-CSF treatment following the first cycle of ifosfamide.

Adolescent↗
PubMed1999

Bone mineral mass and calcium and phosphate metabolism in young men: relationships with vitamin D receptor allelic polymorphisms.

The genetic bases of peak bone mass determinants are still poorly understood, particularly in males. We investigated the relationship between vitamin D receptor (VDR) 3'- and 5'-gene polymorphisms (as determined by the restriction enzymes BsmI and FokI) and bone mineral mass, and calcium and inorganic phosphate (Pi) metabolism in an homogeneous cohort of young healthy men. In 104 healthy subjects, aged 24.3 +/- 3.1 yr (mean +/- SD; range, 20.7-38.7), standardized bone mineral density (BMD; z-scores) at the levels of lumbar spine and femoral trochanter, i.e. bone mineral content adjusted for age, body size, and bone area, significantly differed between VDR 3'-end alleles (BsmI), whereas crude areal BMD or bone mineral content did not. Among BsmI homozygotes BB, BMD (z-scores) were significantly lower only in subjects also carrying the f allele at the VDR-5' polymorphic site (FokI). Serum PTH levels were significantly higher in the BB genotype at baseline and remained so under either a low or a high calcium-phosphorus diet. Moreover, on the low calcium-phosphorus diet, BB subjects had significantly decreased tubular Pi reabsorptive capacity and plasma Pi levels. Our results underline the importance of identifying multiple single base mutation polymorphisms within candidate genes of bone mineral mass and suggest a role for environmental/dietary factor interactions with VDR gene polymorphisms in peak bone mineral mass in men.

Adult↗
PubMed1999

Regulation of ob gene expression: evidence for epinephrine-induced suppression in human obesity.

Leptin acts as satiety factor and increases energy expenditure. Studies conducted on animals and in vitro on adipocytes culture have shown that infusion of catecholamines leads to a significant reduction of ob gene expression; it appears of interest to evaluate the in vivo effects of adrenergic activation on the expression of the ob gene in humans. We studied ob gene expression in adipose tissue samples from 13 obese subjects before and after epinephrine (25 ng/min x kg ideal body weight for 3 h) and 6 obese patients during saline infusion. Hormonal infusion led to a significant increase in epinephrine plasma levels (from 27 +/- 4 to 339 +/- 75 pg/mL; P < 0.001), plasma free fatty acids (from 0.73 +/- 0.05 to 0.98 +/- 0.07; P < 0.05), heart rate (13.5 +/- 3.1 beats/min; F = 2.9; P < 0.03), and systolic blood pressure (F = 2.7; P < 0.05), whereas diastolic blood pressure did not show significant variation. Plasma leptin levels decreased by the end of the infusion (from 63 +/- 13 to 49 +/- 11 ng/mL; P < 0.05), and ob messenger ribonucleic acid levels were significantly reduced (decrease amounting to 47 +/- 5% of basal values). Our study shows that adrenergic activation contributes to regulate ob messenger ribonucleic acid levels in humans. The interaction between epinephrine and leptin may operate during metabolic and psychological stress to regulate energy expenditure and food intake.

Adipose Tissue↗
PubMed1999

Circulating progenitor cell release and functional characterization after topotecan plus G-CSF and erythropoietin in small cell lung cancer patients.

Topotecan is a new antineoplastic agent active in ovarian cancer, with promising activity in small cell lung cancer and predictable toxicity. As a part of our ongoing attempt to optimize the use of disease-specific drugs as circulating progenitor cell (CPC) priming in solid tumors, we have evaluated the effects on CPC release of single-agent Topotecan followed by granulocyte colony-stimulating factor (G-CSF) + human recombinant erythropoietin (rhEPO), together with the cell cycle status of the collected CD34+ cells. Ten pretreated patients with small cell lung cancer received Topotecan (1 mg/m2, i.v. for 5 consecutive days) followed by G-CSF (5 microg/kg/day, s.c.) + rhEPO (10,000 I.U. daily, s.c.), starting 24 h after Topotecan. The combination was well tolerated and no relevant side-effects were recorded. On day +10 (range +9 to +11) after the last dose of Topotecan, the median WBC count and the CD34+ cell peak were 8.2 x 10(3) microl (range 4.9-13.9) and 55 microl (range 28-75), respectively. Using flow cytometry, a detailed cell cycle analysis was performed on these CD34+ cells. The cell cycle distribution was determined by DNA content coupled with bromodeoxyuridine incorporation analysis. Apoptosis was evaluated by quantitating DNA strand breaks. The percentage of CD34+ cells in active S-phase was 10.2+/-5%, while early apoptotic CD34+ cells were detected in a low percentage (5.5+/-3%). Topotecan followed by G-CSF + rhEPO mobilizes CPCs effectively. This sequence exerts a stimulation on CD34+ cell cycle with a protective effect from chemotherapy-induced apoptosis. Taken together, these data could be of value for the incorporation of Topotecan, as well as of the combination of G-CSF and rhEPO, into high-dose chemotherapy programs with CPC support.

Adult↗
PubMed1999

[Surgical treatment of pulmonary metastases of osteosarcoma. Apropos of 206 operated cases].

Two hundred and six patients were operated for lung metastases from osteosarcoma over a period of 7 years. The operative mortality was 0.3%. The actuarial survival for the overall population was 78% at one year. 50% at two years, 40% at three years and 34% at five years. The most significant prognostic factors (p < 0.01) were the number of metastases, the duration of the free interval and the degree of differentiation. Sex, age, site and type of resection of osteosarcoma or the metastases did not have any influence on prognosis. Surgical resection of lung metastases currently constitutes an essential part of the multidisciplinary management of osteosarcoma.

Adolescent↗
PubMed1999

[Transluminal treatment in aneurysm of the abdominal aorta. Role of diagnostic imaging].

PURPOSE: To emphasize the importance of diagnostic imaging: a) in the selection of patients to be treated with the transluminal approach b) during stent-graft positioning c) in the follow-up of treated patients. MATERIAL AND METHODS: From January 1997 to May 1998, twenty-five patients with abdominal aortic aneurysms (AAA) were treated with transfemoral stent-grafts (AneuRx Medtronic). All patients were submitted to a preoperative study including digital angiography (DSA) and Spiral CT. Intraoperatively they underwent DSA and intravascular ultrasound (IVUS). Follow-up was performed with Spiral CT. RESULTS: Twenty-four bifurcated and one straight device were inserted in twenty-five patients with AAA. In two cases it was impossible to position the endoprosthesis due to narrow or tortuous artery access. Following the intention to treat criteria, the technical success rate was 92.5%. All the stents were patent and no dislodgement was observed at follow-up. Partial thrombosis of the stent was observed in three patients. Owing to incomplete distal covering, early endoleak occurred in one patient with an aortoiliac aneurysm; the positioning of two cuffs allowed a successful outcome. CT examination performed 6 months after positioning revealed the presence of endoleaks in three patients, due to persistence of lumbar and inferior mesenteric artery patency. The AAA was no more appreciable in five of the ten patients submitted to CT follow-up one year after the procedure. In three of ten cases it was reduced in size and in two patients there was no change. DISCUSSION: Spiral CT plays a basic role in the selection of patients because it helps assess the length and diameter of the proximal neck, thus permitting to choose the device to be inserted. Preoperative DSA is mandatory in the evaluation of size and tortuosity of the iliac arteries. IVUS allows to monitor the site of delivery during the maneuver and to make the final measurements while DSA plays a role in checking the correct positioning of the device and excluding the presence of endoleaks at the end of the procedure. Late follow-up with Spiral CT aims at demonstrating possible malfunctioning of the endoprosthesis and confirms the definitive exclusion of AAA. CONCLUSIONS: Diagnostic imaging plays a basic role in the endovascular treatment of AAA, much more than that required for traditional surgical treatment. In particular, pretreatment planning is critical and requires sophisticated imaging including Spiral CT with 3D reconstruction and angiographic evaluation using catheters with calibrated markers.

Angioplasty, Balloon↗
PubMed1999

PCTAIRE-1: characterization, subcellular distribution, and cell cycle-dependent kinase activity.

PCTAIRE-1 is a member of the cyclin-dependent kinase (cdk) family whose function is unknown. We examined the pattern of PCTAIRE-1 protein expression in a number of normal and transformed cell lines of various origins and found that the kinase is ubiquitous. Indirect immunofluorescence indicated that PCTAIRE-1 exhibits cytoplasmic distribution throughout the cell cycle. Confocal microscopy showed that PCTAIRE-1 does not colocalize with components of the cytoskeleton or with the endoplasmic reticulum. We found that endogenous PCTAIRE-1 and ectopically expressed PCTAIRE-1 display kinase activity when myelin basic protein is used as an acceptor substrate. Similar to other members of the cyclin-dependent kinase family, PCTAIRE-1 seems to require binding to a regulatory subunit to display kinase activity. PCTAIRE-1 activity is cell cycle dependent and displays a peak in the S and G2 phases. We show that the low level of kinase activity observed until the onset of S phase correlates with elevated tyrosine phosphorylation of the molecule.

Actins↗
PubMed1999

Prospective, randomized trial of sequential interleukin-3 and granulocyte- or granulocyte-macrophage colony-stimulating factor after standard-dose chemotherapy in cancer patients.

BACKGROUND AND OBJECTIVE: Several in vitro and animal studies have shown that IL-3 primes hematopoietic stem cells to become more sensitive to later acting growth factors. We wanted to compare the toxicity and the synergistic stimulatory effect of interleukin-3 (IL-3) followed by granulocyte colony-stimulating factor (G-CFS) or granulocyte-macrophage colony-stimulating factor (GM-CSF) on white blood cell (WBC) and platelet counts, after standard-dose chemotherapy (CT) in patients with solid tumors. DESIGN AND METHODS: Fifty consecutive cancer patients with thrombocytopenia and/or leukopenia registered during a previous course of CT were randomized to receive, after the following course, IL-3 (10 microg/kg/day, s.c., day 1-5) followed by G- or GM-CSF (5 microg/kg/day, day 6-8). RESULTS: The nadir of WBC in the cycles supported with the combination of IL-3 and G-CSF was significantly higher than that observed in the CT cycles not supported by growth factors (p < 0. 005). Furthermore, severe leukopenia was abrogated in all the cycles supported with IL-3+G-CSF, while in the cycles without cytokines, this event was registered in 62.5% of the cases (p < 0.0005). Finally, the recovery of WBC was achieved a mean of 4 days earlier in the cycles supported with IL-3+G-CSF. As for thrombocytoprotection, no significant differences were evidenced, but severe thrombocytopenia was abrogated in all the cycles supported by IL-3+G-CSF (p < 0.05). Furthermore, platelet recovery after CT was achieved on average 3.5 days earlier in the IL-3+G-CSF group than in the previous cycles. The nadir of WBC count in the cycles supported by the combination of IL-3 and GM-CSF was significantly higher than that observed in the CT cycles not supported by growth factors (p < 0.005). Furthermore, severe leukopenia was abrogated in 40% of the cycles supported by IL-3+GM-CSF, while in the cycles without cytokines, this event was registered in 80% of the cases (p < 0.005). Finally, the recovery of WBC was achieved a mean of 3.5 days earlier in the cycles supported by IL-3+GM-CSF. As far as thrombocytoprotection is concerned, there were no significant differences in the nadir between the cycles supported by the association IL-3+GM-CSF and the cycles not supported by cytokines. However, severe thrombocytopenia was registered in 20% of the cycles not supported by growth factors but in only 10% of the cycles supported by IL-3+GM-CSF (p < 0.05). Furthermore, platelet recovery after CT was achieved on average 3 days earlier in the IL-3+GM-CSF group. The combination of IL-3 and G-CSF would appear to be more effective than the combination of IL-3 and GM-CSF in the control of both severe thrombocytopenia and leukopenia. Indeed, severe leukopenia was abrogated in all the cycles in arm A, but only in 40% of the cycles in arm B (p < 0.0005). Furthermore, considering a platelet count below 49

Adult↗
PubMed1998

HIV-associated PML presenting as epilepsia partialis continua.

Two patients with human immunodeficiency virus (HIV) type 1 infection presented new-onset epilepsia partialis continua (EPC) as an early manifestation of progressive multifocal leukoencephalopathy (PML). EPC occurred with no other seizures and was associated with negative radiographic and electrophysiological findings for several weeks. PML represents an increasingly recognized cause of new-onset seizures in both seropositive and seronegative patients, with no report of EPC as a presenting complaint.

AIDS Dementia Complex↗
PubMed1998

Inhibition of myogenesis by transforming growth factor beta is density-dependent and related to the translocation of transcription factor MEF2 to the cytoplasm.

Transforming growth factor beta (TGF-beta) was found to inhibit differentiation of myogenic cells only when they were grown to high density. Inhibition also occurred when myogenic cells were cocultured with other types of mesenchymal cells but not when they were cocultured with epithelial cells. It is therefore possible that some density-dependent signaling mediates the intracellular response to TGF-beta. Within 30 min of treatment, TGF-beta induced translocation of MEF2, but not MyoD, myogenin, or p21, to the cytoplasm of myogenic cells grown to high density. Translocation was reversible on withdrawal of TGF-beta. By using immune electron microscopy and Western blot analysis on subcellular fractions, MEF2 was shown to be tightly associated with cytoskeleton membrane components. To test whether MEF2 export from the nucleus was causally related to the inhibitory action of TGF-beta, we transfected C2C12 myoblasts with MEF2C containing the nuclear localization signal of simian virus 40 large T antigen (nlsSV40). Myogenic cells expressing the chimerical MEF2C/nlsSV40, but not wild-type MEF2C, retained this transcription factor in the nucleus and were resistant to the inhibitory action of TGF-beta. We propose a mechanism in which the inhibition of myogenesis by TGF-beta is mediated through MEF2 localization to the cytoplasm, thus preventing it from participating in an active transcriptional complex.

Animals↗