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Biomedical subjects

E Benedetti

Publications and source records attributed to E Benedetti.

At least 19 recordsLinked to original sources
PubMed2006

Isolated single-cycle attosecond pulses.

We generated single-cycle isolated attosecond pulses around approximately 36 electron volts using phase-stabilized 5-femtosecond driving pulses with a modulated polarization state. Using a complete temporal characterization technique, we demonstrated the compression of the generated pulses for as low as 130 attoseconds, corresponding to less than 1.2 optical cycles. Numerical simulations of the generation process show that the carrier-envelope phase of the attosecond pulses is stable. The availability of single-cycle isolated attosecond pulses opens the way to a new regime in ultrafast physics, in which the strong-field electron dynamics in atoms and molecules is driven by the electric field of the attosecond pulses rather than by their intensity profile.

Journal Article↗
PubMed2006

Bovine lactoferrin for Helicobacter pylori eradication: an open, randomized, multicentre study.

BACKGROUND: Cure rates for eradication of Helicobacter pylori appear to be decreasing, thus more effective therapies must be identified. AIM: To evaluate the efficacy of bovine lactoferrin in the treatment of H. pylori infection. METHODS: In a multicentered prospective study, 402 (mean age 52.4, range 19-84 years) H. pylori-positive patients were assigned to one of three regimens: group A - esomeprazole 20 mg b.d., clarithromycin 500 mg b.d. and tinidazole 500 mg b.d. for 7 days; group B - lactoferrin 200 mg b.d. for 7 days followed by the same schedule of group A; group C - esomeprazole 20 mg b.d., clarithromycin 500 mg b.d. and tinidazole 500 mg b.d. plus lactoferrin 200 mg b.d. for 7 days. RESULTS: Of the 402 patients, 389 completed the study. Six patients were discontinued due to side effects, one patient in group B died and six patients were lost to follow up. The eradication rate (intention-to-treat analysis) was 77% in group A (105/136), 73% in group B (97/132) and 90% in group C (120/134) (chi(2)-test P < 0.01). The incidence of side effects was 9.5% in group A, 9% in group B and 8.2% in group C (chi(2)-test P = 0.1). CONCLUSION: This study demonstrates that bovine lactoferrin is an effective adjuvant to 7-day triple therapy for eradication of H. pylori infection.

Adult↗
PubMed2006

Generation of high-energy self-phase-stabilized pulses by difference-frequency generation followed by optical parametric amplification.

We produce ultrabroadband self-phase-stabilized near-IR pulses by a novel approach where a seed pulse, obtained by difference-frequency generation of a hollow-fiber broadened supercontinuum, is amplified by a two-stage optical parametric amplifier. Energies up to 20 microJ with a pulse spectrum extending from 1.2 to 1.6 microm are demonstrated, and a route for substantial energy scaling is indicated.

Journal Article↗
PubMed2006

Synthesis, characterization and hybridization studies of new nucleo-gamma-peptides based on diaminobutyric acid.

In the present work, we report the synthesis and the characterization of a new chiral nucleoaminoacid, in which a diaminobutyric moiety is connected to the DNA nucleobase by an amidic bond, and its oligomerization to give the corresponding nucleo-gamma-peptide. The ability of this synthetic polymer to bind complementary DNA was studied in order to explore its possible use in antigene/antisense or diagnostic applications. Our interest in the presented DNA analogue was also supported by the importance of gamma-aminoacid-containing compounds in natural products of biological activity and by the known stability of gamma-peptides to enzymatic degradation. Furthermore, our work could contribute to the study of the role of nucleopeptides as prebiotic material in a PNA world that could successively lead to the actual DNA/RNA/protein world, as recently assumed.

Aminobutyrates↗
PubMed2006

Risk factors for wound healing complications in sirolimus-treated renal transplant recipients.

Impaired surgical site healing occurs in 20% to 50% of sirolimus (SRL)-treated renal transplant (RT) recipients, with most patients having received concomitant corticosteroids. We determined the incidence of surgical site complications among RT recipients receiving SRL with mycophenolate mofetil (MMF), with most patients on a steroid-avoidance protocol. SRL/MMF patients with complications within 3 months of transplantation were compared with 1) SRL/MMF patients without them and 2) matched RT recipients receiving tacrolimus (FK)/MMF. Between January 2002 and March 2005, 44 of 300 (15%) RT recipients received SRL within 6 weeks of transplantation. Fourteen (31.8%) developed lymphocele, bladder leak, wound dehiscence, cellulitis, or an abscess. Obesity (BMI > or =30 kg/m2) was significantly associated with problems: the mean BMI of SRL cases with complications was 29.9 kg/m2 vs 25.4 kg/m2 for SRL patients without them (P = .047). Seventy-one percent of obese SRL patients experienced complications compared with 24.3% (P = .025) of non-obese SRL patients. Surgical treatment was required in 29% of patients. Rates of maintenance steroid use were similar in SRL complicated cases compared with SRL patients without them. The FK control group showed a lower rate of complications (14.3%; P = .163) despite similar BMI, rejection rates, and chronic steroid use as the SRL group. Obesity and graft rejection were independent predictors of complications. Thus, among a group of predominantly steroid-free recipients on SRL, the rates of wound complications were similar to those seen previously, but the highest risk for them was observed in obese recipients and in those with acute rejection episodes. Wound complications were associated with significant morbidity.

Adult↗
PubMed2006

Improved outcomes in islet isolation and transplantation by the use of a novel hemoglobin-based O2 carrier.

During isolation, islets are exposed to warm ischemia. In this study, intraductal administration of oxygenated polymerized, stroma-free hemoglobin-pyridoxalated (Poly SFH-P) was performed to improve O2 delivery. Rat pancreata subjected to 30-min warm ischemia were perfused intraductally with collagenase in oxygenated Poly SFH-P/RPMI or RPMI (control). PO2 was increased by Poly SFH-P (381.7 +/- 35.3 mmHg vs. 202.3 +/- 28.2, p = 0.01) and pH maintained within physiological range (7.4-7.2 vs. 7.1-6.6, p = 0.009). Islet viability (77% +/- 4.6 vs. 63% +/- 4.7, p = 0.04) was improved and apoptosis lower with Poly SFH-P (caspase-3: 34,714 +/- 2167 vs. 45,985 +/- 1382, respectively, p = 0.01). Poly SFH-P improved islet responsiveness to glucose as determined by increased intracellular Ca2+ levels and improved insulin secretion (SI 5.4 +/- 0.1 vs. 3.1 +/- 0.2, p = 0.03). Mitochondrial integrity was improved in Poly SFH-P-treated islets, which showed higher percentage change in membrane potential after glucose stimulation (14.7% +/- 1.8 vs. 9.8 +/- 1.4, respectively, p < 0.05). O2 delivery by Poly SFH-P did not increase oxidative stress (GSH 7.1 +/- 2.9 nm/mg protein for Poly SFH-P vs. 6.8 +/- 2.4 control, p = 0.9) or oxidative injury (MDA 1.8 +/- 0.9 nmol/mg protein vs. 6.2 +/- 2.4, p = 0.19). Time to reach normoglycemia in transplanted diabetic nude mice was shorter (1.8 +/- 0.4 vs. 7 +/- 2.5 days, p = 0.02), and glucose tolerance improved in the Poly SFH-P group (AUC 8106 +/- 590 vs. 10,863 +/- 946, p = 0.03). Oxygenated Poly SFH-P improves islet isolation and transplantation outcomes by preserving mitochondrial integrity.

Animals↗
PubMed2005

Controlling two-center interference in molecular high harmonic generation.

We experimentally investigate the process of intramolecular quantum interference in high-order harmonic generation in impulsively aligned CO2 molecules. The recombination interference effect is clearly seen through the order dependence of the harmonic yield in an aligned sample. The experimental results can be well modeled assuming that the effective de Broglie wavelength of the returning electron wave is not significantly altered by the Coulomb field of the molecular ion. We demonstrate that such interference effects can be effectively controlled by changing the ellipticity of the driving laser field.

Journal Article↗
PubMed2005

Measurement of harmonic phase differences by interference of attosecond light pulses.

By using a self-referencing technique, we have experimentally measured the influence of the carrier-envelope phase of femtosecond light pulses on the phase of the electric field of the radiation produced by high-order harmonic generation. We show that, in particular experimental conditions, the temporal evolution of the electric field of the attosecond pulses, is directly controlled by the carrier-envelope phase of the driving pulses.

Journal Article↗
PubMed2005

Expression of peroxisome proliferator-activated receptors (PPARs) and retinoic acid receptors (RXRs) in rat cortical neurons.

Neuronal differentiation is a complex process involving the sequential expression of several factors. The important role of lipid molecules in brain development is well known. Many fatty acid cell signaling activities are mediated by peroxisome proliferator-activated receptors (PPARs). PPARs are ligand-activated transcription factors belonging to the steroid, thyroid and retinoid nuclear receptor superfamily. They are activated by fatty acids and their derivatives. Different isotypes of PPARs (alpha, beta/delta and gamma) have distinct physiological functions depending on their different ligand activation profiles and tissue distribution. PPARs have been involved in neural cell differentiation and death as well as in inflammation and neurodegeneration. Although PPARs have been described in neurons by in situ studies, the presence and possible modulation of these receptors during neuronal differentiation has not been explored yet. In this study we analyzed the expression of PPARs and of their heterodimeric partners, RXRs, in embryonic rat cortical neurons during their in vitro maturation. Our results demonstrate the presence of PPARs alpha, beta/delta and gamma and of RXRs beta and gamma. PPARalpha, beta/delta and gamma are differentially modulated during culture time suggesting that they may be involved in neuronal maturation. In particular, we point toward the PPARbeta/delta isotype as a key factor in neuronal differentiation.

Animals↗
PubMed2005

Highly successful living donor kidney transplantation after conversion to negative of a previously positive flow-cytometry cross-match by pretransplant plasmapheresis.

Between July 2001 and November 2003, 16 patients with a positive flow-cytometry crossmatch to their potential living donor for kidney transplant were treated with desensitization protocol based on plasmapheresis and low-dose IVIg starting 1 week before the scheduled transplant. Twelve patients (75%) converted to negative crossmatch and were successfully transplanted. Immunosuppression consisted of induction with thymoglobulin, tacrolimus, mycophenolate mofetil, and steroids. Plasmapheresis and IVIg were continued on alternate days for the first postoperative week. The 1-year patient and graft survival was 100%. The rate of acute rejection was 41% (16% cellular and 25% humoral). All of the rejection episodes resolved with treatment. Combination of plasmapheresis and IVIg allows successful conversion from positive to negative flow-cytometry crossmatch in 75% of cases; after conversion, kidney transplant can be carried out with a high rate of success.

Adult↗
PubMed2005

Limited-dose Daclizumab versus Basiliximab: a comparison of cost and efficacy in preventing acute rejection.

The purpose of this study was to compare the efficacy and cost of the limited-dose Daclizumab regimen to that of the standard-dose Basiliximab regimen. Two antibody induction regimens were compared in patients aged 18 years and older who received renal transplants from January 2002 to September 2003 and completed interleukin (IL)-2R antibody induction with standard-dose Basiliximab (20 mg x 2 doses) or limited-dose Daclizumab (1 mg/kg x 2 doses). The primary outcome measure was the incidence of acute rejection. Secondary outcomes included cost, changes in serum creatinine level, and delayed graft function. Of the 46 patients randomized, 42 patients completed the 6-month follow-up. Mean serum creatinine level at time of discharge was originally higher in the limited-dose Daclizumab group than the standard-dose Basiliximab group (1.89 vs 1.57, respectively). By 1, 3, and 6 months, mean serum creatinine values were similar between both groups, with a trend toward lower mean serum creatinine values in the limited-dose Daclizumab group. The incidence of acute rejection was also similar between the groups (6% vs 7%). The average cost difference between the 2 regimens was approximately $715. This study suggests that a limited-dose Daclizumab regimen may be an efficacious and less costly alternative to the standard-dose Basiliximab regimen for antibody induction therapy following renal transplantation.

Adult↗
PubMed2005

Immediate conversion from tacrolimus to cyclosporine in the treatment of posttransplantation diabetes mellitus.

Posttransplantation diabetes (PTDM) is a frequent complication of tacrolimus (TAC)-based immunosuppressive therapy after kidney transplantation. We investigated whether immediate conversion from TAC to Cyclosporine (CSA) could reverse or at least improve new-onset PTDM. Between February 2002 and February 2004, 28 adult kidney transplant recipients maintained on TAC were diagnosed with new-onset PTDM. Eight adult patients with new-onset PTDM were enrolled in the study and converted from TAC to CSA, the remaining 20 patients served as controls and were continued on the TAC-based immunosuppression. The conversion to CSA was performed immediately after establishing the diagnosis of PTDM at an average of 11 months posttransplantation. We did not document any episodes of acute rejection or worsening renal function after conversion. After conversion to CSA, among the 3 patients started on insulin, 1 has come completely off antidiabetic medications, whereas 1 required decreased doses of insulin, and the third has been converted to oral medications. Of the 5 patients originally on oral medications, 3 completely discontinued therapy, whereas the other 2 were well controlled on single-drug therapy at reduced doses. After a mean follow-up of 17 months, in the control group 9 of the 16 patients started on oral antidiabetics ultimately required insulin treatment and no patient could stop antidiabetic or insulin therapy. These findings indicate that conversion from TAC to CSA is a simple, safe, and efficacious way to reverse or at least improve PTDM.

Adult↗
PubMed2005

Effect of race on the occurrence of posttransplant diabetes in kidney transplant recipients treated with early steroid discontinuation.

INTRODUCTION: Early steroid discontinuation (within 5 days after transplant) has been associated with a lower incidence of posttransplant diabetes mellitus (PTDM). A retrospective study was done to assess the incidence of PDTM in relation to racial groups in kidney transplant recipients who received early steroid discontinuation. METHODS: Between January 2002 and January 2004, 125 consecutive, primary adult kidney transplant recipients (51 cadaveric donor, 74 living donor) were performed at the University of Illinois at Chicago. The first 34 recipients were treated with steroid maintenance therapy, while the remaining 91 underwent early steroid discontinuation. Group A (n = 91) had steroids discontinued on postoperative day 6 and maintenance immunosuppression consisting of tacrolimus and mycophenolate mofetil. Group B (n = 34) received the same immunosuppression but was maintained on steroids indefinitely. Induction consisted of Thymoglobulin in African-Americans; all others received Simulect. RESULTS: At 1 year, patient and graft survivals were similar in both groups; there was a trend for reduction of acute rejection rates in group A (4% vs 12%). The incidence of PTDM was significantly lower in group A (7%) compared to group B (26%; P = .0209). The incidence of PTDM in group A was limited to Hispanic patients. African-Americans and Caucasians in group A did not experience PTDM (P = .005 compared to African-Americans in group B). CONCLUSION: A steroid-free protocol virtually eliminated the incidence of PTDM in African-Americans and Caucasians but had no effect on the development of PTDM in Hispanic recipients. Alternative immunosuppression may benefit this population.

Adrenal Cortex Hormones↗
PubMed2005

Conformational analysis by NMR and distance geometry techniques of a peptide mimetic of the third helix of the Antennapedia homeodomain.

The Antennapedia homeodomain structure consists of four helices. The helices II and III are connected by a tripeptide that forms a turn, and constitute the well-known helix-turn-helix motif. The recognition helix penetrates the DNA major groove, gives specific protein-DNA contacts and forms direct, or water-mediated, intermolecular hydrogen bonds. It was suggested that helix III (and perhaps also helix IV) might represent the recognition helix of Antennapedia homeodomain, which makes contact with the surface of the major groove of the DNA. In an attempt to clarify the helix III capabilities of assuming an helical conformation when separated from the rest of the protein, we carried out the structural determination of the recognition helix III in different solvent media. The conformational study of fragments 42-53, where residues W48 and F49, not involved in the protein-DNA interaction, were substituted by two alanines, was conducted in sodium dodecyl sulfate (SDS), trifluoroethanol (TFE) and TFE/water, using circular dichroism, nuclear magnetic resonance (NMR) and distance geometry (DG) techniques. The fragment assumes a well-defined secondary structure in TFE and in TFE/water (90/10, v/v) with an alpha-helix encompassing residues 4-9, while in TFE/water (70/30, v/v) a less regular structure was found. The DG results in the micellar system evidence the presence of a distorted alpha-helical conformation involving residues 4-8. Our results reveal that the isolated Antennapedia recognition helix III tend to preserve in solution the alpha-helical conformation even if separated from the rest of the molecule.

Animals↗
PubMed2005

Intra-ductal glutamine administration reduces oxidative injury during human pancreatic islet isolation.

Oxidative stress during islet isolation induces a cascade of events injuring islets and hampering islet engraftment. This study evaluated islet isolation and transplantation outcomes after intra-ductal glutamine administration. Human pancreata deemed unsuitable for pancreas or islet transplantation were treated with either a 5 mM solution of l-glutamine (n = 6) or collagenase enzyme alone (n = 6) through the main pancreatic duct. Islet yield, viability, in vitro function; markers of oxidative stress [malondialdehyde (MDA) and Glutathione (GSH)] and apoptosis were assessed. Islet yields were significantly increased in the glutamine group compared to controls (318, 559 +/- 25, 800 vs. 165, 582 +/- 39, 944 mean +/- SEM, p < 0.01). The amount of apoptotic cells per islet was smaller in the glutamine group than the control. The percentage of nude mice rendered normoglycemic with glutamine-treated islets was higher than the controls (83% n = 10/12 vs. 26% n = 6/23; p < 0.01), and the time to reach normoglycemia was decreased in the glutamine group (1.83 +/- 0.4 vs. 7.3 +/- 3 days; p < 0.01). Glutamine administration increased GSH levels (7.6 +/- 1.7 nmol/mg protein vs. 4.03 +/- 0.5 in control, p < 0.05) and reduced lipid-peroxidation (MDA 2.45 +/- 0.7 nmol/mg of protein vs. 6.54 +/- 1.7 in control; p < 0.05). We conclude that intra-ductal administration of glutamine reduces oxidative injury and apoptosis and improves islet yield and islet graft function after transplantation.

Adult↗
PubMed2004

Ischemic preconditioning protects intestine from prolonged ischemia.

Ischemic preconditioning (IP), obtained by exposure to brief periods of vascular occlusion, improves organ tolerance to prolonged ischemia. The aim of this study was to evaluate the effects of IP on intestinal morphology. Forty rats were subjected to sham surgery (n = 20, group I) or intestinal preconditioning (n = 20, group II) with a cycle of brief ischemia/reperfusion (10-minute occlusion of superior mesenteric artery [SMA], followed by 10-minute reperfusion) before prolonged ischemia produced by SMA occlusion (45 minutes). Five animals in each group were sacrificed 2, 12, 24, and 48 hours after reperfusion. Intestinal samples were processed for light and electron microscopy. A TUNEL assay was performed to detect apoptosis. Statistical analysis used Student t test and Kaplan-Meier survival curves. The overall mortality for the sham-operated group was 15%, while no animals of group II died (NS). Histological evaluation showed early detachment of epithelial cells from villous stroma accompanied by marked congestion and edema. Successive morphological changes were represented by leukocyte infiltration, focal necrosis, and marked villus denudation or loss. Group II animals showed significantly reduced inflammatory infiltrates in the lamina propria and a greater villus height compared to group I. The maximum number of apoptotic nuclei was observed in both groups, Following 2 hours of reperfusion group II animals showed significantly, greater apoptosis at 2 and 12 hours after reperfusion (P <.05). Electron microscopy showed severe mitochondrial and basement membrane damage. The findings from this study confirm that IP preconditioning attenuates morphological alterations that are invariably present after prolonged ischemia and reperfusion.

Animals↗
PubMed2004

A myeloablative allograft after rejection of two consecutive nonmyeloablative transplants from two different HLA identical siblings.

A 55-year-old female with standard risk AML in second CR received an allogenic transplant from an HLA-matched sibling, using a nonmyeloablative conditioning regimen (NMST). On day +139, she rejected her graft with autologous reconstitution. She received a second NMST from a different HLA-matched sibling with an identical conditioning regimen and immunosuppression. On day +110, she rejected the second graft, with autologous reconstitution with blasts. She received a third allograft from the first sibling with a myeloablative busulfan-based conditioning regimen. She is now day +270, in CR, with full donor chimerism.

Female↗