Search PubMed⌕ Search

Biomedical subjects

L Barbieri

Publications and source records attributed to L Barbieri.

At least 19 recordsLinked to original sources
PubMed2002

Current status of local penile therapy.

Guidelines for management of patients with erectile dysfunction indicate that intraurethral and intracavernosal injection therapies represent the second-line treatment available. Efficacy of intracavernosal injections seems superior to that of the intraurethral delivery of drugs, and this may explain the current larger diffusion of the former modality. Safety of these two therapeutic options is well established; however, the attrition rate with these approaches is significant and most patients eventually drop out of treatment. Newer agents with better efficacy-safety profiles and using user-friendly devices for drug administration may potentially increase the long-term satisfaction rate achieved with these therapies. Topical therapy has the potential to become a first-line treatment for erectile dysfunction because it acts locally and is easy to use. At this time, however, the crossing of the barrier caused by the penile skin and tunica albuginea has limited the efficacy of the drugs used.

Administration, Topical↗
PubMed2002

Scleroderma subsets are best detected by the simultaneous analysis of the autoantibody profile using commercial ELISA.

OBJECTIVE: Antinuclear antibodies are often present in patients with systemic sclerosis but do not provide useful prognostic information if studied individually. Although an autoantibody profile should be studied, this has never been done in a large series of patients. METHODS: Anticentromere, anti-topoisomerase-I, anti-extractable-nuclear-antigen, antihistone and anticardiolipin antibodies were studied by means of enzyme immunosorbent assay in 90 systemic sclerosis patients. RESULTS: We confirmed that anticentromere antibodies characterize limited forms of the disease with less frequent visceral involvement while anti-topoisomerase-I antibodies characterize diffuse forms with severe gastrointestinal, heart and lung involvement. Antihistone antibodies alone or associated with anticentromere antibodies characterize a disease subset with more frequent visceral involvement and a probably poor outcome. Patients with anticardiolipin antibodies, instead, did not display severer heart or vascular involvement. CONCLUSIONS: Systemic sclerosis patients are often found to have antinuclear antibodies. In addition to the well-known disease subsets identified by anti-topoisomerase-I and anticentromere antibodies, another one can be established, characterized by antihistone antibodies often associated with anticentromere antibodies. Patients displaying this profile have high prevalence of lung, kidney and heart involvement.

Adult↗
PubMed2000

Sildenafil taken at bedtime significantly increases nocturnal erections: results of a placebo-controlled study.

OBJECTIVES: Nighttime erections occur at all ages and contribute to the maintenance of the morphodynamic integrity of smooth muscle cells within the corpora cavernosa. This study was aimed at evaluating the effect on nocturnal erections of sildenafil versus a placebo taken at bedtime. METHODS: A double-blind, crossover, placebo-controlled study design was used to examine the effects of sildenafil and placebo on sleep-related erectile activity. Thirty selected patients with erectile dysfunction (vasculogenic etiology, 22 patients [73%]; psychogenic etiology, 8 patients [27%]) were submitted to a polysomnographic recording of nocturnal erections, using a RigiScan device during 3 consecutive nights. After a first night of adaptation, the 2 following nights were used to study patients after the administration of sildenafil (100 mg) or a placebo taken at bedtime. RESULTS: Twenty-three patients (77%) showed a significantly improved nocturnal erectile activity (according to the calculation of rigidity and tumescence activity units) after the administration of sildenafil (P <0.01), 5 patients (17%) showed comparable nocturnal erections with sildenafil and placebo, and 2 patients (6%) showed a significantly improved nocturnal erectile activity after taking the placebo (P <0.05). Overall, mean rigidity and tumescence activity values at the tip and base of the penis were significantly improved after sildenafil rather than placebo administration (P <0.001). The duration of tip rigidity greater than 60% was significantly longer during the night with sildenafil (P <0. 001). Although the number of erectile episodes was greater during the sildenafil night, this did not reach statistical significance. CONCLUSIONS: In most patients with good sleep efficiency and who have erectile dysfunction, sildenafil, rather than a placebo, taken at bedtime produces a significantly improved nocturnal erectile activity. Further studies are needed to verify whether this preliminary finding may constitute the basis for the use of sildenafil as a tool for preventing erectile dysfunction.

Adult↗
PubMed2000

Polynucleotide:adenosine glycosidase activity of saporin-L1: effect on various forms of mammalian DNA.

Saporin-L1 from the leaves of Saponaria officinalis belongs to a group of plant polynucleotide:adenosine glycosidases, known as ribosome-inactivating proteins due to their property of depurinating the major rRNA. Previous experiments indicated that saporin-L1 and other ribosome-inactivating proteins depurinate also DNA [Barbieri et al. (1994) Nature 372, 324; and (1996) Biochem. J. 319, 507-513]. Here we describe the effects of highly purified nuclease-free saporin-L1 on mammalian nuclear and mitochondrial DNA. Saporin-L1 had less activity on mitochondrial DNA than on nuclear DNA. A low, although significant, depurination of both chromatin and whole nuclei was observed. Mitochondrial nucleic acids are heavily depurinated in intact mitochondria, although the contribute of mtDNA to the deadenylation events is not known. The kinetic constants for several substrates were determined.

Animals↗
PubMed2000

Polynucleotide:Adenosine glycosidase is the sole activity of ribosome-inactivating proteins on DNA.

Polynucleotide: adenosine glycosidases (PNAG) are a class of plant and bacterial enzymes commonly known as ribosome-inactivating proteins (RIP). They are presently classified as rRNA N-glycosidases in the enzyme nomenclature [EC 3.2.2.22]. Several activities on nucleic acids, other than depurination, have been attributed to PNAG: in particular modifications induced in circular plasmids, including linearisation and topological changes, and cleavage of guanidinic residues. Here we describe a chromatographic procedure to obtain nuclease-free PNAG by dye-chromatography onto Procion Red derivatized Sepharose((R)). Highly purified enzymes depurinate extensively pBR322 circular, supercoiled DNA at neutral pH and exhibit neither DNase nor DNA glycolyase activities, do not cause topological changes, and adenine is the only base released from DNA and rRNA, even at very high enzyme concentrations. A scanning force microscopy (SFM) study of pBR322 treated with saporin-S6 confirmed that (i) this PNAG binds extensively to the plasmid, (ii) the distribution of the bound saporin-S6 molecules along the DNA chain is markedly variable, (iii) plasmids already digested with saporin-S6 do not appear fragmented or topologically modified. The observations here described demonstrate that polynucleotide:adenosine glycosidase is the sole enzymatic activity of the four ribosome-inactivating proteins gelonin, momordin I, pokeweed antiviral protein from seeds and saporin-S6. These proteins belong to different families, suggesting that the findings here described may be generalized to all PNAG.

Chromatography, Gel↗
PubMed2000

Identification and analysis of bacterial protein secretion inhibitors utilizing a SecA-LacZ reporter fusion system.

Protein secretion is an essential process for bacterial growth, yet there are few if any antimicrobial agents which inhibit secretion. An in vivo, high-throughput screen to detect secretion inhibitors was developed based on the translational autoregulation of one of the central protein components, SecA. The assay makes use of a SecA-LacZ fusion reporter construct in Escherichia coli which is induced when secretion is perturbed. Several compounds, including two natural product extracts, which had the ability to induce the reporter fusion were identified and the MICs of these compounds for Staphylococcus aureus strain MN8 were found to be < or =128 microg/ml. Enzyme-linked immunosorbent assay, Western blotting, and immunoprecipitation techniques were used to analyze the affects of these compounds on protein secretion. Six representative compounds presented here appear to be bona fide secretion inhibitors but were found to have deleterious effects on membranes. It was concluded that, while the method described here for identifying inhibitors of secretion is valid, screens such as this, which are directed against the membrane-bound portion of a pathway, may preferentially identify compounds which affect membrane integrity.

Adenosine Triphosphatases↗
PubMed2000

Polynucleotide: adenosine glycosidase activity of immunotoxins containing ribosome-inactivating proteins.

Polynucleotide:adenosine glycosidases (rRNA N-glycosidases, EC 3.2.2.22, more commonly known as ribosome-inactivating proteins, RIP) are a numerous family of plant and bacterial enzymes, shown to release also adenine from DNA in vitro. They are well suited for the preparation of specifically toxic conjugates with several carriers, including monoclonal antibodies (immunotoxins). Here we show that (i) immunotoxins containing various PNAG (dianthin, gelonin, momordin I, PAP-S, PDS-2, ricin A-chain, saporin-L1, saporin-S6) all act on DNA; (ii) activity on DNA in vitro is less compromised by disulphide linkage to antibody than is inhibition of cell-free protein translation; and (iii) specific cytotoxicity of immunotoxin does not correlate with substrate specificity.

Adenine↗
PubMed2000

Evidence based assessment of long-term results of plaque incision and vein grafting for Peyronie's disease.

PURPOSE: We assessed the long-term outcome of plaque incision and vein grafting in select patients with Peyronie's disease by extensive preoperative and postoperative subjective and objective analysis. MATERIALS AND METHODS: From January 1995 to June 1998, 50 men 28 to 62 years old (mean age 44) underwent surgery. Patients were evaluated preoperatively, 3 months after surgery and at a mean long-term followup of 32 months by sexual history, physical examination, determination of penile length and degree of curvature, dynamic color power Doppler sonography of the penile vessels and nocturnal RigiScan* evaluation for 3 nights. Study inclusion criteria were penile curvature 45 degrees or greater that made vaginal intromission impossible, stable disease for at least 6 months, patient reported normal penile rigidity, normal penile hemodynamics on color power Doppler ultrasound, normal nocturnal penile rigidity with at least 1 erection nightly (including base and tip rigidity greater than 60%, and a duration of 10 minutes) and absent base-tip discrepancies. Plaque was usually approached via a combined subcoronal and midline sagittal scrotal incision. Maximal rigidity was created intraoperatively and 1 to 3 plaque incisions were made. Saphenous vein patches were then grafted at the incision sites. Postoperatively patients were systemically treated with neurotrophic factors and low molecular weight heparin. Local vacuum supported corporeal stretching was done and weekly alprostadil injections were given to optimize corporeal oxygenation. RESULTS: At long-term followup complete penile straightening was achieved in 40 cases (80%), minor residual curvature of 30 degrees or less persisted in 7 (14%) and significant disease recurred in 3 (6%). Penile rigidity was equal to that preoperatively in 47 patients (94%), while 3 (6%) reported clinically significant decreased potency. Penile length was equal to that preoperatively in 30 patients (60%), while 20 (40%) noticed slight penile shortening. Postoperatively penile color power Doppler sonography showed vascular impairment in 5 men (10%) and nocturnal RigiScan testing revealed a significant decrease in nightly erections in 5 (10%). Surgical complications included penile hypoesthesia in 1 case (2%), penile hematoma in 2 (4%), wound infection in 1 (2%) and glandular ischemia in 1 (2%). CONCLUSIONS: Plaque incision and vein grafting achieved satisfactory clinical results in the majority of patients with severe and stable Peyronie's disease, intact penile rigidity preoperatively, normal penile color power Doppler ultrasound and normal nocturnal RigiScan testing.

Adult↗
PubMed1999

Preparation of highly purified momordin II without ribonuclease activity.

Momordin II, a ribosome-inactivating protein from Momordica charantia seeds, was purified by a procedure involving a series of chromatographies on S-Sepharose, Sephadex G-50, CM-Sepharose, and Red Sepharose columns. Highly purified momordin II inhibited cell-free protein synthesis, released adenine from rat liver ribosomes and from DNA, and had no RNase activity.

Adenine↗
PubMed1998

A rapid and sensitive method to measure the enzymatic activity of ribosome-inactivating proteins.

A method is described in which the adenosine- N -glycosidase activity of ribosome-inactivating proteins (RIPs) is measured using as substrate a 2251 bp [3H]DNA obtained by PCR amplification of the 731-2981 region of the pBR322 plasmid. The DNA, labelled in the purine ring of adenine, proved a good substrate for all three RIPs tested (PAP-S, ricin and shiga-like toxin I). The method, which measures directly the [3H]adenine released, is highly specific, extremely rapid and quantitative in a wide range of RIP concentrations.

Adenine↗
PubMed1998

Genital plus audiovisual sexual stimulation following intracavernous vasoactive injection versus re-dosing for erectile dysfunction--results of a prospective study.

PURPOSE: We assessed whether re-dosing of a vasoactive agent or the combination of a vasoactive injection and genital plus audiovisual sexual stimulation caused the greatest erectile effect to determine which of the 2 procedures would be better for dynamic penile color Doppler sonography in patients with erectile dysfunction. MATERIALS AND METHODS: A total of 20 consecutive patients with erectile dysfunction underwent 2 sessions under real-time RigiScan* recording of penile erection. Session 1 consisted of adaptation in 10 minutes, intracavernous injection of 10 micrograms. alprostadil in 10 minutes and re-dosing of 10 micrograms. alprostadil in 10 minutes. Session 2 consisted of adaptation in 10 minutes, injection of 10 micrograms. alprostadil in 10 minutes and genital plus audiovisual sexual stimulation in 10 minutes. The total duration of each session was 30 minutes. The order of the 2 sessions was randomly assigned with a week interval between each session. RESULTS: Re-dosing and genital plus audiovisual sexual stimulation caused a significant increase in erectile response compared to the result seen after the first injection (re-dosing p < 0.05, injection plus stimulation p < 0.01). However, erectile response after the genital stimulation session was significantly greater than that after re-dosing (p < 0.01). An erection comparable to the greatest spontaneous erection reported by the patient was much more frequently achieved after genital stimulation than after the re-dosing session (p < 0.01). CONCLUSIONS: The combination of injection and stimulation caused a significantly greater erectile response than re-dosing. We suggest that the former should always be used during color Doppler sonography to optimize the accuracy of the test. Re-dosing is suggested when an incomplete erectile response occurs after the injection plus stimulation phase.

Adult↗
PubMed1998

Counterimmunoelectrophoresis, ELISA and immunoblotting detection of anti-Ro/SSA antibodies in subacute cutaneous lupus erythematosus. A comparative study.

Patients with subacute cutaneous lupus erythematosus (SCLE) have circulating antibodies to Ro/SSA directed to two antigenically distinct ribonucleoproteins of 60 kDa and 52 kDa. Three laboratory tests may be used to detect anti-Ro/SSA antibodies: counterimmunoelectrophoresis (CIE), enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB). Their relative efficacy and clinical correlations were ascertained. We determined anti-Ro/SSA antibodies with CIE, with two different ELISA methods (ELISA 1 and 2) and with IB in 29 SCLE patients. Anti-52 kDa and -60 kDa Ro/SSA antibodies were also assayed with IB. In addition, we determined antinuclear antibodies with indirect immunofluorescence, anti-Sm, anti-RNP, anti-La/SSB and anti-Ro/SSA antibodies with CIE and ELISA, and anti-nDNA and cardiolipin antibodies using an ELISA method. CIE detected anti-Ro/SSA antibodies in 22 patients while ELISA 1 and 2 did so in 17 and 18 patients, respectively. In five patients, IB revealed a reactivity to 60 kDa polypeptides and in two, a reactivity to 52 kDa polypeptides. Of these seven patients, four had a myocardial infarction. Of these, two reacted to the 52 kDa antigen and two to the 60 kDa antigen. A combination of techniques was often needed to detect all specificities. ELISA proved to be very specific and sensitive. The IB technique detected a group of patients with myocardial infarction. A case-control study is needed to confirm the data of cardiac involvement.

Adult↗
PubMed1998

The effect of ribosome-inactivating proteins on the ribosome from the hyperthermophilic archaeon Sulfolobus solfataricus.

Protein synthesis in the thermoacidophilic archaeon Sulfolobus solfataricus (Ss) was inhibited by polynucleotide:adenosine glycosylase activity of some type 1 ribosome-inactivating proteins (RIP). The target of RIP was S. solfataricus rRNA that was depurinated thus producing inactive ribosomes. The amount of RIP required to half-inactivated Ss-ribosomes was comparable to that needed for eubacterial ribosomes, but two orders of magnitude higher than that required for mammalian ribosomes. In addition, RIP treated Ss-ribosomes were also less efficient in stimulating the ribosome dependent GTPase activity of the S. solfataricus elongation factor 2 (SsEF-2) thus suggesting that the inhibition of protein synthesis was probably due to the lack of the interaction between depurinated Ss-ribosomes and SsEF-2. Since SsEF-2 protects Ss-ribosomes against RIP activity it can be hypothesised that also on Ss-ribosomes the sites of interaction for the translocation factor 2 and the RIP are topographically close.

Archaeal Proteins↗