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L Vicari

Publications and source records attributed to L Vicari.

At least 19 recordsLinked to original sources
PubMed2002

Nonlinear optical characterization of cluster dynamic in water in oil microemulsion by a pump probe laser beam technique.

We present a new pump probe laser beams configuration for the nonlinear optical characterization of microemulsions. We detect the variation of the on-axis optical intensity of the probe beam as generated by the concentration profile induced in an optically thin film of microemulsion by the pump beam. A mathematical model has been introduced to describe the phenomenon. The technique allows the determination of both Kerr-like optical nonlinearity and time constants and, therefore, it gives information both on cluster dimension and their shape. We discuss its application to WAD (water/AOT/decane, where AOT denotes sodium-bis-di-ethyl-sulfosuccinate) with the application of a strong electric field of optical source. Comparison between theoretical predictions and experimental results confirms the presence of giant optical nonlinearity in the absence of turbidity divergence. Chainlike shape of clusters, of the kind already reported with the application of strong electric field, could justify this result.

Journal Article↗
PubMed2000

Lipophilic methotrexate conjugates with antitumor activity.

Lipophilic methotrexate (MTX)-lipoamino acid conjugates coupled with amide or ester linkages (1a-1r) were synthesised. The inhibitory activity of the conjugates was evaluated on bovine liver DHFR. The in vitro growth inhibitory effect against MTX-sensitive human lymphoblastoid CCRF-CEM cells and an MTX-resistant sub-line (CEM/MTX), which displays defective intracellular transport of MTX, was determined under short-term and continuous (120-h incubation) exposure conditions. The alpha, gamma, or alpha,gamma amide conjugates showed different activity in inhibiting the growth of parent cells. CEM/MTX cells were much less susceptible than CCRF-CEM cells to inhibition by alpha or alpha,gamma-substituted lipoamino acid conjugates, whereas both cell lines were almost equally sensitive to the MTX-gamma conjugates. Although less potent than MTX, they could partially circumvent the impaired transport system. These findings confirm that lipophilic MTX conjugates may be good lead compounds on the drug development for the treatment of some MTX-resistant tumors. Ester-type conjugates displayed an interesting activity against parent CCRF-CEM cells, although they were less potent against the transport-resistant sub-line. Stability studies on these molecules indicated that they are not degraded into MTX in the culture medium, thus suggesting that they are not able to over-cross cell resistance despite of their lipophilicity.

Animals↗
PubMed1999

Ornithine decarboxylase gene expression in Castleman's disease.

Castleman's disease (CD) is a rare atypical lymphoproliferative disorder that is clinically and histologically heterogeneous and is associated with the risk of developing malignant lymphoma. Based on pathological findings CD is divided into two types: a localized form and a multicentric form. The clinical course differs in these two forms. We examined the molecular mechanisms that lie between benign and malignant disease, evaluating a possible implication of oncogenes in the pathogenesis. Since deregulated expression of the gene for ornithine decarboxylase (ODC) has been observed in a variety of human malignancies, we compared ODC expression between the localized and multicentric forms. Using northern blot analysis we found that ODC gene expression clearly differs between the localized and multicentric forms. The findings in this report indicate that the variable pattern of ODC gene expression in the different types of CD could be useful for examining the evolution of this disease.

Adult↗
PubMed1996

Molecular and cytogenetic characterization of a recurrent unbalanced translocation (4;21)(p16.3;q22.1): relevance to the Wolf-Hirschhorn and Down syndrome critical regions.

We report on an aneuploidy syndrome due to the unbalanced segregation of a familial translocation (4;21)(p16.3;q22.1) causing a partial 4p monosomy and a partial 21q trisomy. The three affected children presented with severe failure to thrive, short stature, microcephaly, profound hypotonia, and mental retardation. The face, very similar in the three children, is characterized by frontal bossing, upslanting of the palpebral fissures, short nose, and deep set ears, giving the overall appearance of the Down syndrome. The molecular study has defined the aneuploid segment on both 4p and 21q. Most of the Down syndrome critical region was found to the trisomic, while only part of the candidate Wolf-Hirschhorn syndrome critical region was deleted, suggesting that this region is not critical for the major malformations characteristic for WHS.

Abnormalities, Multiple↗
PubMed1996

Interstitial 9q deletion is associated with CD7+ acute leukemia of myeloid and T lymphoid lineage.

We report the clinical, hematological and immunophenotypic characteristics from four cases of acute leukemia with interstitial deletion of chromosome 9, ie del(9)(q12-q22), as a single chromosomal abnormality. Three patients had acute myeloblastic leukemia (AML) and one T origin acute lymphoblastic leukemia (ALL). According to FAB classification, blasts were classified as M1 (two patients), M2 (one patient), and L2 (one patient). In two out of three AML cases a myelodysplastic syndrome, one AREB-t and one AREB diagnosed 6 and 11 months before respectively, preceded the onset of AML. Morphological examination showed dysgranulopoiesis, dyserythropoiesis and cytoplasmic vacuoles in two AML patients, while a strong positivity to myeloperoxidases was observed in all AML cases. As concerns immunophenotypic findings, blast cells from two of three AML patients expressed CD7 and CD34, while those from the T-ALL case displayed CD33 and CD34 along with CD7. These observations suggest that del (9q) is associated with CD7+ acute leukemia of myeloid or lymphoid lineage.

Adolescent↗
PubMed1995

Simultaneous occurrence of tetrasomy 21 and trisomy 8 in a patient with early blastic metamorphosis of chronic myeloproliferative disorder.

We report an unusual hyperdiploid karyotype characterized by the simultaneous occurrence of tetrasomy 21 and trisomy 8 detected during early blastic evolution of a BCR-ABL-negative chronic myeloproliferative disorder. Blast cells from this patient showed a striking response to all-trans-retinoic acid (ATRA)-induced differentiation as evaluated by CD15 expression following in vitro exposure to this inducer. Our report represents the first description of such a composite karyotype in human hematologic malignancies.

Aged↗
PubMed1995

Double isochromosome 8q as single cytogenetic aberration in acute myelo-monocytic leukemia.

We report a case of double isochromosome 8q as a single cytogenetic abnormality in a patient with acute myelo-monocytic leukemia. Similarly to rare cases with tetrasomy 8, the patient showed monocytic involvement and was refractory to cytotoxic chemotherapy. We conclude that this kind of cytogenetic aberration is probably associated with distinct morphologic and clinical characteristics.

Aneuploidy↗
PubMed1994

A novel chromosomal abnormality detected in a case of acute myelomonocytic leukemia.

A not yet recorded translocation, t(3:17)(q21;q23), detected in a case of acute myelomonocytic leukemia, is reported. In spite of an aggressive cytotoxic chemotherapy, the disease showed a rapid fatal course, confirming the dismal prognostic significance of structural, 'primary' chromosomal abnormalities in acute leukemias.

Chromosomes, Human, Pair 17↗
PubMed1985

[Teratogenic and goitrogenic activity of propineb and propylenethiourea in the rat].

The teratogenic and goitrogenic effects of Propineb, dithiocarbamate pesticide and Propylenthiourea (PLTU), its metabolite and degradation product have been studied. The aim of this study was to show the possible correlation between the two activities. Female Sprague-Dawley rats were treated with Propineb and PLTU starting from 6th to 16th day of pregnancy. The functional state of maternal and foetal thyroid, the toxicity of products versus dams and embryotoxic and teratogenic effects were examined. The observed goitrogenic effect may be compared to that reported in the previous studies of the authors, if considering time of sacrifice. In fact, the lesion quickly rises and as rapidly regresses when treatment is stopped. The foetal thyroid has not been affected by the product administered to the dams. PLTU showed a clear teratogenic activity at doses that did not show any maternal toxicity (45 and 90 mg/k).

Animals↗
PubMed1983

Expression of rDNA insertions during rDNA magnification in D. melanogaster.

In D. melanogaster, many ribosomal genes contain an intervening sequence that interrupts the 28S rRNA gene. In wild-type flies, type I and type II insertions are rarely transcribed and the transcripts of the interrupted genetic units do not contribute significantly to the production of mature ribosomal RNA. We demonstrate that during rDNA magnification, transcription of short type I sequences and of type II sequences is respectively, about 4- and about 16-fold that observed in unmagnified homozygous bobbed females used as control. In subsequent generation (bbm1) we have observed, for transcription of short type I sequences, that this elevated level is maintained and, for transcription of type II sequences, that the level reverts to one comparable with the control. Transcription of both insertion sequences decreases in subsequent generations (bbm19), reaching a level comparable with the controls.

Base Sequence↗
PubMed1981

Selective replication of ribosomal DNA repeats after loss of the abnormal oocyte phenotype in Drosophila melanogaster.

Drosophila melanogaster females homozygous for the abnormal oocyte mutation produce a large excess of female offspring when crossed with XY/0 males. After several generations in abo homozygous stock, this maternal effect is no longer observed. The disappearance of the abo phenotype is coupled with an increase in the amount of DNA coding for rRNA (rDNA). We have used restriction endonuclease analysis of total DNA extracted from adult females and from single female larval brains to investigate the molecular organization of rDNA before and after the loss of abo phenotype. The rDNA increase is associated with variations of the restriction pattern of the nontranscribed spacer, probably due to a selective increase of rDNA repeats.

Animals↗
PubMedDate not supplied

Lyoprotected nanosphere formulations for paclitaxel controlled delivery.

The preparation and technological characterization of nanosphere formulations (NS) containing the anticancer drug paclitaxel (PTX) are reported. Poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) nanospheres (NS) were prepared by a solvent displacement method. They showed a mean particle size in the range 150-300 nm, with a high homogeneity (polydispersity index < 0.3). For long term stability, NS require additional procedures, such as freeze-drying. In this study, the effect on NS particle size and surface charge of different lyoprotectants (mono- and disaccharides, polyalcohols, and hydroxypropyl-beta-cyclodextrin) at various concentrations was tested by means of light scattering size analysis. The formulations freeze-dried with the addition of 10% glucose (w/v) showed interesting characteristics after freeze-drying. They were chosen for specific studies on drug encapsulation efficiency, in vitro drug release and biological activity on the human anaplastic thyroid carcinoma cell line 8305C. The PLGA NS, in particular, showed a cell growth inhibitory activity comparable to the free drug.

Antineoplastic Agents↗