25 research outputs found
Oral escalating dose of cyclosporine-a combined with 4-epidoxorubicin in advanced colorectal-cancer - a phase-I study.
No full textMultidrug resistance, a major factor in the resistance to drugs, can be reversed by cyclosporin A. It is generally given by intravenous route. The aim of the present study was to assess the possibility of achieving useful plasma levels, giving cyclosporin A orally in advanced colorectal cancer patients treated with 4-epidoxorubicin. Cyclosporin A was given orally twice a day, for four days. The starting study dose was 5 mg/kg. Dose in cohorts of 3 patients was escalated to 10, 15, 20, 30, 40 mg/kg if the previous dose was not able to determine the target blood level (2,000 ng/ml). Cyclosporin A blood levels were analyzed by a specific fluorescence polarization immunoassay method (TDx; Abbot Laboratoires, North Chigaco, IL). 4-epidoxorubicin was given at a fixed dose of 75 mg/m(2), every 3 weeks. None of the dose levels of cyclosporin A given orally produced the target blood level. Only two patients, receiving cyclosporin at a dose of 30 mg/kg, and two after a CsA dose of 40 mg/kg, presented blood levels higher than 1,000 ng/ml, but however, lower than 1,500 ng/ml. In conclusion, the oral route of administration of cyclosporin does not seem recommendable in order to reverse multidrug resistance because it is not able to produce sufficient plasma levels
Carboplatin associated anemia treated with subcutaneous erythropoietin - a pilot-study.
No full textIn nineteen patients with carboplatin-induced anemia (hemoglobin less than 90 g/l), recombinant human erythropoietin was administered subcutaneously three times a week on an outpatient basis. The initial dose was 50 Units/kg of body weight. If response was not achieved within 3 weeks, dose was increased to 75 Units/kg. Using the same criteria further escalations to 100 and 150 Units/kg were performed. If there was no response erythropoietin was terminated. Two patients obtained an increase of hemoglobin levels greater than 100 g/l, which was considered as a clinical response in this study, with a dose of 75 U/kg; eleven patients needed an erythropoietin dose of 100 U/kg and three a dose of 150 U/kg. The other three patients required hemotransfusions and were considered non responders. Hemoglobin increases occurred despite continuation of carboplatin chemotherapy. In conclusion, subcutaneous eryhtropoietin is effective and safe in the treatment of carboplatin-induced anemia
Correlation among [h-3] thymidine, flow-cytometry and proliferating cell nuclear antigen indexes in colorectal tumors.
No full textIn colorectal cancer and other tumors, proliferating cell nuclear antigen (PCNA) has been found to be a useful marker in immunohistochemical studies of cell proliferation, The presence of a correlation among PCNA labeling index (PCNA LI) and values of cell proliferation expressed by [H-3]thymidine labeling index (TLI) and flow cytometry (FC), the most common techniques used in the evaluation of proliferative activity in colorectal cancer were studied. In 50 operable colorectal cancer patients, TLI, PCNA LI and determination of S-phase fraction by FC were carried out in order to evaluate the correlation among these three indices. A good correlation was obtained between PCNA LI and both TLI (r=0.667; P=0.0001) and percent of cells in S-phase as determined by FC (r=0.819; P=0.0001). It is concluded that PCNA immunohistochemistry can be a reliable marker of the proliferative activity in colorectal rumours. Furthermore, because of its technical simplicity and lower cost it can be more advantageous than TLI or FC
La coltivazione della palma da datteri: una linea di continuità dalla preistoria ai nostri giorni
No full textIl ritrovamento di grandi quantità di datteri in due siti archeologici, uno dell'Età delFerro nel Sultanato di Oman e uno di Età Classica-Tardo Garamantico in Libia meridionale, hapermesso di ricostruire due episodi nella millenaria storia della coltivazione della palma cheriveste un ruolo fondamentale nell'economia agricola dei paesi subtropicali aridi. Le indaginimorfometriche rivelano, in entrambi i siti, una continuità di valori all’interno dell’intervallodimensionale dei semi. Ciò porta a ipotizzare la presenza di una sola varietà di palma incoltivazione oppure la coesistenza di più varietà e dei loro ibridi
Iridium-Doped Nanosized Zn-Al Layered Double Hydroxides as Efficient Water Oxidation Catalysts
No full textLayered double hydroxides (LDHs) are an ideal platform to host catalytic metal centers for water oxidation (WO) owing to the high accessibility of water to the interlayer region, which makes all centers potentially reachable and activated. Herein, we report the syntheses of three iridium-doped zinc-aluminum LDHs (Ir-LDHs) nanomaterials (1-3, with about 80 nm of planar size and a thickness of 8 nm as derived by field emission scanning electron microscopy and powder X-ray diffraction studies, respectively), carried out in the confined aqueous environment of reverse micelles, through a very simple and versatile procedure. These materials exhibit excellent catalytic performances in WO driven by NaIO4 at neutral pH and 25 °C, with an iridium content as low as 0.5 mol % (∼0.8 wt %), leading to quantitative oxygen yields (based on utilized NaIO4, turnover number up to ∼10,000). Nanomaterials 1-3 display the highest ever reported turnover frequency values (up to 402 min-1) for any heterogeneous and heterogenized catalyst, comparable only to those of the most efficient molecular iridium catalysts, tested under similar reaction conditions. The boost in activity can be traced to the increased surface area and pore volume (>5 times and 1 order of magnitude, respectively, higher than those of micrometric materials of size 0.3-1 μm) estimated for the nanosized particles, which guarantee higher noble metal accessibility. X-ray absorption spectroscopy (XAS) studies suggest that 1-3 nanomaterials, as-prepared and after catalysis, contain a mixture of isolated, single octahedral Ir(III) sites, with no evidence of Ir-Ir scattering from second-nearest neighbors, excluding the presence of IrO2 nanoparticles. The combination of the results obtained from XAS, elemental analysis, and ionic chromatography strongly suggests that iridium is embedded in the brucite-like structure of LDHs, having four hydroxyls and two chlorides as first neighbors. These results demonstrate that nanometric LDHs can be successfully exploited to engineer efficient WOCs, minimizing the amount of iridium used, consistent with the principle of the noble-metal atom economy
Synthesis and Characterization of Zwitterionic Metallates and Molecular Clusters
No full textThis thesis reports the synthesis and characterization of novel zwitterionic metallates of Rh and Pd with the ligand EtNHC(S)PPh2=NPPh2C(S)NEt (HEtSNS). This ligand is an amphoteric zwitterion, which forms the H2EtSNS+ cation upon protonation and the EtSNS- dianion–cation upon deprotonation.
Determination of absolute pKa in CH2Cl2 by a spectrophotometric titration and kinetic/thermodynamic studies of the oxidative addition of methyl iodide to the zwitterionic metallate complex [Rh(CO)EtSNS] and its derivatives obtained by protonation: [Rh(CO)EtSNS]·HA and [Rh(CO)EtSNS]·2HA, where A = PF6, OTf, NO3 by 1H NMR spectroscopy are discussed.
The reaction of the zwitterionic ligand with [Ru3(CO)12] affords an unprecedented methideylamide –N(Et)CH(R)– μ3-bridging moiety.
Finally, enchainment cooperativity effects in neutrally charged bimetallic Nickel (II) phenoxyiminato polymerization catalysts and enhanced selectivity for polar comonomer are reported
Synthesis and Characterization of Zwitterionic Metallates and Molecular Clusters
No full textThis thesis reports the synthesis and characterization of novel zwitterionic metallates of Rh and Pd with the ligand EtNHC(S)PPh2=NPPh2C(S)NEt (HEtSNS). This ligand is an amphoteric zwitterion, which forms the H2EtSNS+ cation upon protonation and the EtSNS- dianion–cation upon deprotonation.
Determination of absolute pKa in CH2Cl2 by a spectrophotometric titration and kinetic/thermodynamic studies of the oxidative addition of methyl iodide to the zwitterionic metallate complex [Rh(CO)EtSNS] and its derivatives obtained by protonation: [Rh(CO)EtSNS]·HA and [Rh(CO)EtSNS]·2HA, where A = PF6, OTf, NO3 by 1H NMR spectroscopy are discussed.
The reaction of the zwitterionic ligand with [Ru3(CO)12] affords an unprecedented methideylamide –N(Et)CH(R)– μ3-bridging moiety.
Finally, enchainment cooperativity effects in neutrally charged bimetallic Nickel (II) phenoxyiminato polymerization catalysts and enhanced selectivity for polar comonomer are reported.ope
Carbostannolysis Mediated by Bis(pentamethylcyclopentadienyl)lanthanide Catalysts. Utility in Accessing Organotin Synthons
No full textFacile carbon–tin bond activation in the reaction
of 2-(trimethylstannyl)pyridine
(1) with the organolanthanide complexes Cp*2LaCH(TMS)2 (2a) and [Cp*2LaH]2 (2b) yields Cp*2La(2-pyridyl) (3), as well as Me3SnCH(TMS)2 and Me3SnH, respectively. At room temperature, ethylene then undergoes
insertion into the resulting La–C(pyridyl) bond followed by
carbostannolysis to catalytically generate 2-(2-(Me3Sn)ethyl)pyridine
(4) or, with extended reaction times, 6-ethyl-2-(2-(trimethylstannyl)ethyl)pyridine
(5). In contrast to 1, 6-methyl-2-(trimethylstannyl)pyridine
(6) is unreactive, likely reflecting steric constraints.
With terminal alkynes, this catalytic heterocycle–SnMe3 activation/carbostannylation process affords tin-functionalized
conjugated enynes. Thus, at 60 °C 2b catalyzes the
conversion 1 + 1-hexyne to yield (E)-2-butyl-1-(Me3Sn)-oct-1-en-3-yne in a 60:1 ratio E:Z isomer ratio. This reaction is available to α-monosubstituted
and α-disubstituted terminal alkynes, while α-trisubstituted
alkynes are too hindered for reaction. The catalytic cycle is proposed
to proceed via a spectroscopically detectable Me3Sn–alkynyl
intermediate which undergoes insertion into a Cp*2La–alkynyl
bond to produce the conjugated alkynyl product, which is subsequently
protonolyzed from the Cp*2La center by a new terminal alkyne
substrate molecule. NMR spectroscopic and kinetic data support the
proposed pathway and indicate turnover-limiting alkyne insertion
In Situ Formation of a Sub-Nanometer Iridium Phosphide Catalyst from Supported Organometallic Species
No full textWhile several metal phosphides have
attracted significant attention in the last several years due to their
potential use as photocatalytic and hydrotreating catalysts, iridium phosphide
has remained largely unexplored. In this work, silica-supported pincer-iridium
species are thermolyzed, resulting in deconstruction of the tridentate ligand
precursor and formation of a sub-nanometer iridium phosphide phase
characterized by 31P magic angle spinning nuclear magnetic resonance
(31P-MAS-NMR), X-ray absorption spectroscopy (XAS), and high angle
annular dark field scanning transmission electron microscopy (HAADF-STEM). The
support material was found to play an active role in determining the product of
the surface thermolysis, with the silica supported material generating
phosphorus rich iridium phosphide nanoparticles. The resulting silica-supported
iridium phosphide phase is explored as a thermocatalyst for non-oxidative butane
dehydrogenation, achieving high initial reaction rates up to 900 molbutenes molcatalyst-1
hr-1 and a terminal olefin selectivity of up to 70 %.</p
In Situ Formation of a Sub-Nanometer Iridium Phosphide Catalyst from Supported Organometallic Species
No full text
