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Biomedical subjects

E Leone

Publications and source records attributed to E Leone.

At least 19 recordsLinked to original sources
PubMed2001

Bactericidal activity of Pistacia lentiscus mastic gum against Helicobacter pylori.

In this study we evaluated the antibacterial activity of mastic gum, a resin obtained from the Pistacia lentiscus tree, against clinical isolates of Helicobacter pylori. The minimal bactericidal concentrations (MBCs) were obtained by a microdilution assay. Mastic gum killed 50% of the strains tested at a concentration of 125 microg/ml and 90% at a concentration of 500 microg/ml. The influence of sub-MBCs of mastic gum on the morphologies of H. pylori was evaluated by transmission electron microscopy. The lentiscus resin induced blebbing, morphological abnormalities and cellular fragmentation in H. pylori cells.

Anti-Bacterial Agents↗
PubMed2001

Time marches on.

Explore the source record for details and available documents.

Dentistry↗
PubMed2001

[Tubercular spondylodiscitis with multiple abscesses in a teenager: clinical and diagnostic considerations].

We describe a case of TBC spinal column infection complicated by vertebral abscesses in an immigrant teenager. We underline the importance of always suspecting a tubercular illness when fever has unknown origins, and when patients come from countries where TBC is still endemic. We reaffirm, for early and accurate diagnosis, the importance of abdominal echography and spinal tomography.

Abscess↗
PubMed1997

Lymphogranuloma venereum: a case report in an Italian traveller.

A 38-year-old man with a recent history of travel in India and unprotected sexual intercourse with Indian women, was admitted with painful enlarged lymphnodes predominantly in the right inguinal area. Diagnosis of lymphogranuloma venereum was made by means of a positive immunofluorescence test (Total Ig titer of 1:512) and a positive detection of chlamydial antigens by ELISA in a semen sample. He was successfully treated with ciprofloxacin. This observation emphasizes the relevance of infection due to C. trachomatis serotypes L1-L3 that may be acquired during travel in developing countries.

Adult↗
PubMed1997

In vitro antimicrobial properties of azidothymidine (AZT).

In addition to the activity against a number of retroviruses, azidothymidine (AZT) has antibacterial activity against many bacteria. The effect of AZT on 224 bacterial species, including 25 strains of Salmonella spp. isolated from HIV-positive patients, was tested. AZT had no activity against all the strains of tested Gram-positive bacteria and Pseudomonas species (MIC > 128 micrograms/ml), whereas a different activity against Enterobacteriaceae (MIC range, 128 to 0.06 micrograms/ml) was found. In particular 76% of Salmonella spp. isolated from HIV-positive patients showed MICs > 1 microgram/ml, whereas similar MICs value were found in 50% of the Salmonella strains isolated from HIV-negative subjects. In addition, strains of Salmonella isolated from stools were more resistant to AZT when compared to strains isolated from blood even if this difference was not statistically significant. No correlation was found between length of therapy and Salmonella resistance to AZT in HIV-positive patients and a low incidence of Salmonella relapses in subjects treated with AZT was observed. The possibility that AZT may have an ancillary benefit in controlling some bacterial infections in AIDS patients is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Chlamydia pneumoniae infection in Italian patients.

Of 91 adult patients with respiratory tract infections, 13 (14%) had serological evidence of recent infection with Chlamydia pneumoniae. The clinical picture was consistent with asthmatic bronchitis in three patients, whilst exacerbations of chronic obstructive pulmonary disease were present in five subjects and, pneumonia was diagnosed in the remaining five. Our findings provide evidence of an aetiological association between C. pneumoniae and respiratory infections in our region (Bari, South Italy).

Antibodies, Bacterial↗
PubMed1993

Factor analysis and computerized EEG: preliminary data on schizophrenic patients.

Factor Analysis can extract salient features from EEG data and reduce redundancy of multi-channel computerized EEG data. A 16-channel computerized frequency analysis of background brain electrical activity during 3 functional conditions (eyes closed, eyes open and hyperventilation) was carried out in two groups, fifty healthy subjects and twenty-three schizophrenics. The power log-transformed relative values of normal subjects and schizophrenic patients were submitted to Factor Analysis and the resulting factor scores were compared. Schizophrenics showed EEG abnormalities in delta 2, theta 1 and alpha 2 bands for the first factor, accounting for the eyes closed condition, and in theta 2 and beta 2 bands for the second factor, accounting for the eyes open condition. This preliminary study demonstrates the utility of Factor Analysis in managing and comparing computerized EEG data.

Adult↗
PubMed1990

In vitro inhibition of HeLa cell nuclear ribonucleases by ADP-ribosylation.

Ribonuclease activity in HeLa cell nuclei is markedly inhibited by ADP-ribosylation following incubation of intact isolated nuclei with [14C]NAD. Time course experiments demonstrate that [14C] incorporation into proteins is accompanied by a 50% inhibition of ribonuclease activity on single-strand and double-strand polynucleotides. Inhibition does not occur when 3-aminobenzamide, a potent (ADP-ribose) polymerase inhibitor, is present. Two enzymatic activities that degrade double-strand polynucleotides have been purified and partially characterized. A relevant level of radioactivity resulting from [14C]NAD incubation of nuclei was associated to the purified enzyme. The RNase F1 component, which shows maximal activity on polyU-polyA is demonstrated to be the major ADP-ribose acceptor protein.

Cell Nucleus↗
PubMed1989

Purification and identification of ADP-ribosylated proteins from bull testis intact nuclei.

Isolated, intact bull testis nuclei were incubated with [14C] NAD. A large amount of radioactivity was associated to loosely bound chromosomal proteins extracted with 0.35M NaCl and fractionated with trichloroacetic acid. The labelled nuclear proteins included essentially a number of components belonging to the low mobility group. Mg2(+)-catalyzed alkali digestion of radioactive proteins and further analysis demonstrated that the final products were 5'-AMP and phospho-ribosyl-AMP, which arise from the hydrolysis of poly(ADP-ribose).

Amino Acids↗
PubMed1988

ADP-ribosylation of a specific protein from isolated intact bull testis nuclei.

ADP-ribosylation of a specific basic protein has been investigated in isolated intact bull testis nuclei incubated with NAD+. The electrophoretic mobility, molecular weight and amino-acid composition of the purified bull testis specific protein are similar to those of rat testis protein. About 1-5% of the total radioactivity incorporated in the 20% acid-insoluble fraction was associated with testis protein and was identified as ADP-ribose.

Adenosine Diphosphate Ribose↗
PubMed1987

Inhibition of ADP-ribosylation of histone H1 by analogs of diadenosine 5',5'''-p1,p4-tetraphosphate.

The effects of analogs of diadenosine 5',5'''-p1,p4-tetraphosphate (Ap4A) were examined on the ADP-ribosylation reaction of histone H1 catalysed by purified bovine thymus poly(ADP-ribose)transferase. Among the compounds tested, epsilon Ap4A and ApCH2pppA were shown to be the most efficient inhibitors of the enzyme. From kinetic studies of their action, it appears that epsilon Ap4A and ApCH2pppA might be 'mixed type' inhibitors.

Adenine Nucleotides↗
PubMed1987

Complete amino-acid sequence of bovine seminal ribonuclease, a dimeric protein from seminal plasma.

The complete amino-acid sequence of BS-RNAse, a dimeric ribonuclease isolated from bovine seminal plasma, was determined. The reduced and S-carboxymethylated subunit chain of the enzyme was cleaved by trypsin and chymotrypsin. The resulting peptides, purified by cation-exchange chromatography were sequenced by dansyl-Edman, subtractive Edman degradation and carboxypeptidase A and B digestion. Chymotryptic peptides were used for the alignment. Automated Edman degradation of the native protein, through the N-terminal 41 amino-acid residues, completed the sequence information. The subunit chain of BS-RNAse, composed of 124 amino-acid residues, with a molecular mass of 13,610 Da, is highly homologous (81%) to pancreatic ribonuclease A. A good degree of homology (31%) was also found with human angiogenin. No N-linked carbohydrate-attachment sites, such as Asn-X-Ser/Thr, were found in the protein.

Amino Acid Sequence↗
PubMed1986

Reversible inactivation of ribonucleases by ADPribosylation.

The activity of purified bovine seminal RNAase and pancreatic RNAase A (EC 3.1.27.5) has been investigated following in vitro ADPribosylation in the presence of nuclear ADPribosyltransferase (EC 2.4.2.30) and NAD+ X ADPribosylation of these enzymes was correlated with a significant decrease in their activities. Approximately three residues of ADPribose were present per mol of enzyme. Removal of the bound ADPribose restored enzyme activity to near normal levels. Similar results were obtained with nuclei isolated from bull seminal vesicles as an endogenous source of seminal RNAase and nuclear ADPribosyltransferase. The findings suggest that in vitro ADPribosylation has a reversible inactivating effect on ribonucleases.

Adenosine Diphosphate Ribose↗
PubMed1986

In vitro poly(ADP-ribosyl)ation of seminal ribonuclease.

The site of in vitro ADP-ribosylation of seminal ribonuclease was determined. Seminal enzyme was found to be a good receptor of [14C]ADP-ribose residues under the reaction conditions used. The recovery of [14C]ADP-ribosylated RNase was about 65% after purification. After tryptic digestion of modified enzyme, a fraction containing [14C]ADP-ribosylated peptides was separated from the others by ion-exchange chromatography on M82 resin. Radioactive peptides were then purified by affinity chromatography on anti-poly(ADP-ribose)IgG-Sepharose. High performance liquid chromatography of a mixture obtained after pronase digestion of purified ADP-ribosylated peptides revealed only one radioactive peptide whose amino acid composition corresponded to a peptide that has equimolar quantities of aspartic acid, serine, and glycine. Carboxypeptidase Y digestion of this peptide showed that its amino acid sequence was Asp-Ser-Gly. Only position 14-16 of seminal RNase corresponded to this sequence. The chemical stability of the ADP-ribose/enzyme linkage indicated that aspartic acid 14 is the modification site in seminal RNase.

Amino Acid Sequence↗
PubMed1984

A ribonuclease from human seminal plasma active on double-stranded RNA.

A ribonuclease, active on single- and double-stranded RNAs, has been isolated from human seminal plasma 3-5 micrograms of enzyme were recovered per ml of seminal plasma, equivalent to 71% of total activity and a 2500-fold purification (measured with poly(A) X poly(U) as substrate) from the initial dialyzed material. Similar amounts of RNAase were found per g (wet weight) of human prostate, where the enzyme appears to be produced. Human seminal RNAase degrades poly(U) 3-times faster than poly(A) X poly(U), and poly(C) or viral single-stranded RNA about 10-times faster than poly(U). Degradation of poly(A) X poly(U), viral double-stranded RNA, and poly(A) by human seminal RNAase is 500-, 380- and 140-times more efficient, respectively, than by bovine RNAase A. The enzyme, a basic protein with maximum absorbance at 276 nm, occurs in two almost equivalent forms, one of which is glycosylated. Mr values of the glycosylated and non-glycosylated form are 21000 and 16000, respectively. The amino-acid composition of the RNAase is very similar to that of human pancreatic RNAase. The same is true for the carbohydrate content of its glycosylated form.

Amino Acids↗