PubMed Health⌕ Search

Biomedical subjects

Eugenio Benvenuto

Publications and source records attributed to Eugenio Benvenuto.

9 recordsLinked to original sources
PubMed2006

Peptide display on Potato virus X: molecular features of the coat protein-fused peptide affecting cell-to-cell and phloem movement of chimeric virus particles.

The potexvirus Potato virus X (PVX) can be modified genetically to generate chimeric virus particles (CVPs) carrying heterologous peptides fused to coat protein (CP) subunits. A spontaneous PVX mutant expressing a truncated, but functional, form of the CP has been isolated. With the aim of exploiting this virus to display peptides useful for vaccine formulations, two novel viral expression vectors based on pPVX201 (bearing the wild-type PVX genome) were constructed encoding the truncated CP. Both vectors were able to produce infectious virus particles in planta and were used to insert a panel of sequences encoding peptides of biopharmaceutical interest as N-terminal fusions to the truncated cp gene. The analysis of infection progression induced by the different constructs enabled identification of two important structural features of the fused peptide, namely tryptophan content and isoelectric point, critically affecting the formation of PVX CVPs and virus movement through the plant. These results are discussed in view of the rising interest in engineered plant viruses for development of peptide-based epitope vaccines.

Capsid Proteins↗
PubMed2005

Gastric cancer precursor lesions and Helicobacter pylori infection in patients with partial gastrectomy for peptic ulcer.

The mucosa of the gastric stump is considered at greater risk of dysplastic and neoplastic changes than that of the intact stomach. The combination of enteric reflux and Helicobacter pylori infection may have a synergistic damaging effect on the mucosa of the gastric remnant, both producing and increasing mucosal proliferation. The aim of this study was to assess whether the occurrence of H. pylori infection in the remnant mucosa of partially gastrectomized subjects for peptic ulcer disease is associated with an increase of the mucosal precursor lesions of malignancy. A series of 151 subjects who underwent partial gastrectomy for peptic ulcer disease were submitted to upper digestive endoscopy for long-term surveillance. Biopsy specimens of the gastric stump were tested for the occurrence of H. pylori infection and for the presence of precancerous mucosal lesions. The prevalence of H. pylori colonization in the remnant stomach was less than 30% and similar in subjects with different time intervals between gastrectomy and endoscopy. Age at surgery (chi(2): p = 0.03) and H. pylori infection (chi(2): p = 0.002) were significantly associated with the grading of mucosal lesions. The prevalence of normal mucosa was 10 times higher in H. pylori-negative patients as in H. pylori-positive ones (22.0% vs. 2.4%), and the prevalence of intestinal metaplasia was four times higher in H. pylori-positive patients than in H. pylori-negative ones (19.6% vs. 4.6%). We concluded that H. pylori infection may play a causal role in the development of gastric lesions in the operated stomach.

Adult↗
PubMed2005

Immunomodulation of cucumber mosaic virus infection by intrabodies selected in vitro from a stable single-framework phage display library.

Immunomodulation by the ectopic expression of intracellular antibodies ('intrabodies') has a great potential for interfering with physiological or pathological functions in vivo in a highly specific manner. One of the major obstacles of this technology is the inability of most antibodies to properly fold and function in the reducing environment of the cytoplasm, which prevents the formation of essential disulfide bonds. We wished to assess the intracellular performance of antibodies derived from a semi-synthetic single-chain variable fragment (scFv) phage display library ('F8 library') built on a thermodynamically stable single-framework scaffold. To this purpose, we chose to modulate the infection of a pandemic plant pathogen, the cucumber mosaic virus (CMV). After in vitro 'biopanning' on immobilized virions, two scFvs were biochemically characterized, showing high affinity toward the antigen. They were transiently expressed at high yields as soluble molecules in the cytoplasm of Nicotiana benthamiana plants. Subsequently, they were expressed in the cytoplasm of transgenic tomato plants. Challenge with high viral dose showed that both scFvs were able to elicit a phenotypic effect and led to the identification of a transgenic line fully resistant to infection. In these plants, the scFv binds the virus in the inoculated leaves preventing viral long distance movement. This work represents the first demonstration that the 'F8 library' can be directly screened in vitro to rapidly isolate antigen-specific scFvs that act as effective intrabodies in vivo. These antibodies represent powerful tools to interfere with several intracellular targets, modulating pathogen infectivity and/or cellular metabolism.

Antibodies, Monoclonal↗
PubMed2005

Is desmoplasia a protective factor for survival in patients with colorectal carcinoma?

BACKGROUND & AIMS: The role of desmoplasia in colorectal carcinoma progression is unclear and the presence of collagen stroma may represent a barrier against cancer diffusion and vascular invasion or a stroma to build up and support the tumor. The aim of this study was to evaluate the effect of desmoplastic response on long-term survival of patients who underwent radical resection for colorectal carcinoma. METHODS: The study included 429 patients who underwent radical colorectal resection for cancer with a median follow-up period of 72.8 months. RESULTS: At univariate analysis significant associations were observed between desmoplasia and histologic type, parietal infiltration, growth pattern, and staging. No associations were found between desmoplasia and the other clinical and histologic parameters. The multivariate analysis stratified for tumor stage revealed that the factor showing the most favorable influence on time to death was desmoplasia. The presence of desmoplasia was likely to decrease the failure rate to a third of the rate experienced by patients without desmoplasia. Parietal infiltration was associated with an increased risk for a shortened time to death. CONCLUSIONS: Our results favor the view that desmoplasia is a protective factor for survival in patients with colorectal carcinoma. This finding is consistent with the hypothesis that desmoplasia may prevent cancer invasiveness by building a barrier against tumor diffusion.

Adenocarcinoma↗
PubMed2005

Production of an engineered killer peptide in Nicotiana benthamiana by using a potato virus X expression system.

The decapeptide killer peptide (KP) derived from the sequence of a single-chain, anti-idiotypic antibody acting as a functional internal image of a microbicidal, broad-spectrum yeast killer toxin (KT) was shown to exert a strong microbicidal activity against human pathogens. With the aim to exploit this peptide to confer resistance to plant pathogens, we assayed its antimicrobial activity against a broad spectrum of phytopathogenic bacteria and fungi. Synthetic KP exhibited antimicrobial activity in vitro towards Pseudomonas syringae, Erwinia carotovora, Botrytis cinerea, and Fusarium oxysporum. KP was also expressed in plants by using a Potato virus X (PVX)-derived vector as a fusion to the viral coat protein, yielding chimeric virus particles (CVPs) displaying the heterologous peptide. Purified CVPs showed enhanced antimicrobial activity against the above-mentioned plant pathogens and human pathogens such as Staphylococcus aureus and Candida albicans. Moreover, in vivo assays designed to challenge KP-expressing plants (as CVPs) with Pseudomonas syringae pv. tabaci showed enhanced resistance to bacterial attack. The results indicate that the PVX-based display system is a high-yield, rapid, and efficient method to produce and evaluate antimicrobial peptides in plants, representing a milestone for the large-scale production of high-added-value peptides through molecular farming. Moreover, KP is a promising molecule to be stably engineered in plants to confer broad-spectrum resistance to phytopathogens.

Anti-Bacterial Agents↗
PubMed2003

Engineering stable cytoplasmic intrabodies with designed specificity.

Many attempts have been made to develop antibody fragments that can be expressed in the cytoplasm ("intrabodies") in a stable and functional form. The recombinant antibody fragment scFv(F8) is characterised by peculiarly high in vitro stability and functional folding in both prokaryotic and eukaryotic cytoplasm. To dissect the relative contribution of different scFv(F8) regions to cytoplasmic stability and specificity we designed and constructed five chimeric molecules (scFv-P1 to P5) in which several groups of residues important for antigen binding in the poorly stable anti-hen egg lysozyme (HEL) scFv(D1.3) were progressively grafted onto the scFv(F8) scaffold. All five chimeric scFvs were expressed in a soluble form in the periplasm and cytoplasm of Escherichia coli. All the periplasmic oxidised forms and the scFv(P3) extracted from the cytoplasm in reducing conditions had HEL binding affinities essentially identical (K(d)=15nM) to that of the cognate scFv(D1.3) fragment (K(d)=16nM). The successful grafting of the antigen binding properties of D1.3 onto the scFv(F8) opens the road to the exploitation of this molecule as a scaffold for the reshaping of intrabodies with desired specificities to be targeted to the cytoplasm.

Amino Acid Sequence↗
PubMed2003

Musarmins: three single-chain ribosome-inactivating protein isoforms from bulbs of Muscari armeniacum L. and Miller.

Three new ribosome-inactivating protein (RIP; EC 3.2.2.22) isoforms that we have named musarmins (MUs) 1, 2 and 3 have been isolated from the bulbs of Muscari armeniacum L. and Miller by ion-exchange chromatography and gel filtration. Analysis by electrophoresis revealed that they are single-chain proteins and mass spectrometry analysis afforded Mr values of 28,708, 30,003 and 27,626 for MUs 1, 2 and 3, respectively. Musarmins strongly inhibited protein synthesis carried out by mammalian ribosomes, with IC50 values in the 0.14-0.24nM range but not that carried out by plant cell-free systems or HeLa cells. MUs promote the single depurination of rabbit reticulocyte 28S rRNA. cDNA cloning of genes coding for musarmins revealed that they contain open reading frames of 298, 294 and 295 aminoacids for MU1, MU2 and MU3, respectively. Mature MU1, MU2 and MU3 contain 277, 273 and 273 aminoacids, respectively suggesting post-translational C-terminal processing. An untranslated mRNA coding for an ORF very similar to that of MU3 was detected in leaves. Each of the four MU genes contains an intron. In contrast to other RIPs, MUs are present only in bulbs and are not induced in leaves either by senescence, or by treatment of leaves with H2O2 or salicylic acid, or by growth in darkness. Therefore, these proteins could play a non-vital role in plants; for instance, as anti-pathogens and protective agents only in some stages of the plant life cycle (237).

Amino Acid Sequence↗
PubMedDate not supplied

A late complication of pelvic radiotherapy: leiomyosarcoma of the rectum. Report of a case and review of the literature.

Leiomyosarcoma of the rectum is an uncommon malignancy; it accounts for less than 0.1% of all malignancies of the colon and rectum and only one case has been reported long-term following pelvic radiotherapy. We report a second case of leiomyosarcoma of the rectum after radiotherapy in an elderly women who received external radiation therapy eighteen years before, for endometrial carcinoma. We confirm that leiomyosarcoma may be a late uncommon effect of pelvic irradiation and suggest that close and long-term surveillance of irradiated patients is highly recommended.

Aged↗