Biomedical subjects

Giovanni Tosi

Publications and source records attributed to Giovanni Tosi.

14 recordsLinked to original sources

PubMed2026

H5N1 Clade 2.3.4.4b Infections in Domestic Cats During an Avian Influenza Outbreak in Italy: Implications for One Health Surveillance.

BACKGROUND: H5Nx goose/Guangdong (Gs/GD) lineage highly pathogenic avian influenza (HPAI) viruses pose a significant public health threat due to their global spread, mutation accumulation, and expanding host range. The descendant clade 2.3.4.4b has been causing widespread infections in birds and increasing spillover events in mammals. METHODS: This report documents the first fatal case of highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b infection in a domestic cat in Italy, detected in early January 2025. The cat (CAT 1) resided on a backyard poultry farm experiencing a high pathogenicity avian influenza outbreak and succumbed rapidly following the onset of respiratory signs. A second exposed cat (CAT 2) developed clinical disease without fatal outcome. Comprehensive outbreak investigations were conducted, including pathological, serological, molecular analyses, and genomic characterization. RESULTS: Pathological examination of CAT 1 revealed acute necrotizing bronchointerstitial pneumonia, non-suppurative meningoencephalitis, and disseminated foci of hepatic necrosis. Interestingly, the PB2-E627K mutation associated with mammalian virus adaptation was observed in the feline viral isolate compared to avian isolates. Such polymerase complex mutations are key determinants of host range and increase pathogenicity in mammals. CAT 2 from the same farm tested negative for AIV genome detection but subsequently seroconverted for antibodies against NPA, H5, and N1. CONCLUSION: Sharing these findings is crucial for surveillance aimed at enabling early identification of increased risks to human and animal health, preventing cross-species viral transmission and mitigating the risk of potential spillover events.

Animals↗

PubMed2006

Phylogenetic analysis of partial S1 and N gene sequences of infectious bronchitis virus isolates from Italy revealed genetic diversity and recombination.

A total of ten infectious bronchitis virus (IBV) isolates collected from commercial chickens in Italy in 1999 were characterized by RT-PCR and sequencing of the S1 and N genes. Phylogenetic analysis based on partial S1 gene sequences showed that five field viruses clustered together with 793/B-type strains, having 91.3-98.5% nucleotide identity within the group, and one isolate had very close sequence relationship (94.6% identity) with 624/I strain. These two IBV types have been identified in Italy previously. The other three variant isolates formed novel genotype detected recently in many countries of Western Europe. For one of these variant viruses, Italy-02, which afterwards became the prototype strain, the entire S1 gene was sequenced to confirm its originality. In contrast, phylogenetic analysis of more conserved partial N gene sequences, comprising 1-300 nucleotides, revealed different clustering. Thus, three variant IBVs of novel Italy-02 genotype, which had 96.7-99.2% S1 gene nucleotide identity with each other, belonged to three separate subgroups based on N gene sequences. 624/I-type isolate Italy-06 together with Italy-03, which was undetectable using S1 gene primers, shared 97.7% and 99.3% identity, respectively, in N gene region with vaccine strain H120. Only one of the 793/B-type isolates, Italy-10, clustered with the 793/B strain sharing 99.3% partial N gene identity, whereas the other four isolates were genetically distant from them (only 87.7-89.7% identity) and formed separate homogenous subgroup. The results demonstrated that both mutations and recombination events could contribute to the genetic diversity of the Italian isolates.

Animals↗

PubMed2006

PLA-microparticles formulated by means a thermoreversible gel able to modify protein encapsulation and release without being co-encapsulated.

The aim of this work was to develop a novel strategy for the formulation of biodegradable PLA microspheres as delivery systems for proteins or peptides. The strategy is based on the exploitation of the gel-sol transition of the thermoreversible Pluronic F127 gel. The gel allows the formation of the particles without be co-entrapped in the matrix. The microspheres prepared using the novel technique (TG-Ms, or thermoreversible gel-method microspheres) were characterized in vitro (as concerns the size, the morphology, the protein encapsulation, the release and the protein distribution in the polymer matrix), in comparison with microspheres prepared using the classical double emulsion/solvent evaporation method (w/o/w-Ms). Two types of bovine serum albumin (BSA), with different water solubility, were used as model proteins. TG-Ms exhibited small size (7-50 m) and high protein content (8.6%, w/w) regardless of the BSA water solubility, in contrast with w/o/w-Ms, which revealed a size range of 100-130 microm and a protein content related to the BSA water solubility. TG-Ms, in spite of their smaller size respect of the w/o/w-Ms, displayed a reduced initial burst effect and a higher rate in the second release phase that resulted in a quasi-constant profile. The release behavior of the TG-Ms may be attributable to both the localization of the protein in the particle core, as shown by the confocal laser scanning microscopy analysis on labeled-BSA loaded microspheres, and the few pores in the matrix, as shown by the scanning electron microscopy. A working hypothesis about the mechanism of the particle formation was also discussed.

Drug Compounding↗

PubMed2006

Nanoparticulate drug carriers based on hybrid poly(D,L-lactide-co-glycolide)-dendron structures.

We describe a general method for incorporating target moieties in a well-defined arrangement into the surface of biocompatible polyester poly(D,L-lactic-co-glycolic acid) (PLGA) materials using dendrons. In this way it is possible to obtain nanoparticles (NPs) with a high degree of surface coverage. This new strategy was successfully applied to the preparation of peptide- and beta-D-glucose-covered NPs. The first application is based on the discovery of NPs made of conjugates between PLGA and short peptidic sequences able to cross the blood-brain barrier (BBB) after systemic administration. In this paper, we used a branched structure (dendron) in order to prepare a derivative of PLGA able to form, by simple nanoprecipitation, NPs with a higher degree of surface coverage than previously reported by us, characteristic that could influence the uptake by the liver and spleen. The NPs thus obtained retain the ability to cross the BBB and possess a core-shell structure, as evidenced from zeta-potential, X-ray photoelectron (ESCA) spectroscopy and elemental analyses. These results are comparable with the NPs obtained by the derivatization of preformed NPs. The same strategy, namely the use of a branched spacer (a dendron or a G1 dendrimer) inserted between one end of the PLGA chain and a derivatizing molecule, was also successfully applied to obtain beta-D-glucose-covered NPs; in this case, the surface analysis of the NPs was performed by using high resolution magic angle spinning (HRMAS) NMR spectroscopy and zeta-potential measurements.

Animals↗

PubMed2006

Vegetable cells in Papanicolaou-stained cervical smears.

Vegetable cells are unusual findings in Papanicolaou-stained cervical smears; these structures could be wrongly mistaken for abnormal human cells, worm eggs, or spores by a cytologist encountering the possibility of meeting those elements in cytological analysis. Five cervicovaginal smears showing similar vegetable cells have been detected over a 3-yr period (2002-2004) in the course of a population screening program for cancer of the uterine cervix in Modena (Italy) involving 32,500 women. According to the clinical histories of the patients, the vaginal pharmaceutical drugs or appliances used were of different types: vaginal lavages, pessaries, and vaginal creams. Following a careful investigation, the only substance that can lead to vegetal elements has been identified as polysaccharide galactomannan, which is one of the excipient present in the drugs used. The authors have identified the origin of these contaminants and the means of pollution, using cytological and pharmaceutical investigation.

Adolescent↗

PubMed2006

Comparison between drug-eluting stents and beta-radiation for the treatment of diffuse in-stent restenosis: clinical and angiographic outcomes.

BACKGROUND: Initial reports on drug-eluting stents (DES) for the treatment for in-stent restenosis (ISR) show very good outcomes. Nevertheless, few data are available on direct comparison with intracoronary brachytherapy (IBT). The aim of this study was to compare brachytherapy and DES in treatment of diffuse ISR. METHODS: One hundred forty-one consecutive patients with diffuse ISR were treated with IBT (68 patients; beta (90Sr/90Y) emitters) or with DES (73 patients; 32 with sirolimus-eluting and 41 with paclitaxel-eluting stents). Angiographic and clinical follow-up was scheduled within 9 months. RESULTS: The first 74 lesions were treated with IBT (group 1) and the latter 74 with DES (group 2). The two groups were well matched for clinical/angiographic characteristics. At follow-up, restenosis rates were 37.8% (28/74) in IBT group and 14.9% (11/74) in DES group (P = .0028). A diffuse pattern of recurrence was more frequent after IBT (20/74 vs 6/74, P = .005). A worse outcome after IBT was associated with the "edge effect," accounting for most failures. Recurrence within the original restenotic stent was similar in both groups (12.9% vs 14.9% in groups 1 and 2 respectively, P = .8). CONCLUSIONS: Drug-eluting stents are more effective than IBT with beta-irradiation in reducing recurrence rates after treatment of diffuse ISR. In case of failure, the pattern of restenosis is more benign after treatment with DES.

Aged↗

PubMed2005

Peptide-derivatized biodegradable nanoparticles able to cross the blood-brain barrier.

Injectable nanoparticulate drug carriers (Np) able to cross the blood-brain barrier (BBB) have important potential applications for the treatment of diseases that affect the central nervous system (CNS). With the aim to create a system able to address Np to the CNS, we synthesized conjugates between a biodegradable copolymer, poly(D,L-lactide-co-glycolide) (PLGA), and five short peptides, by means of an amidic linkage. These peptides, that are similar to synthetic opioid peptides, were synthesized in turn by means of Fmoc solid-phase peptide synthesis. The new five modified copolymers thus obtained turned out to be valuable starting material for the preparation of Np; these were made fluorescent, in order to allow their localization after their administration, by inclusion of a fluorescent probe. The Np thus prepared were characterized (morphology, size and z-potential) and were shown to possess the peptidic moieties on their surface, as evidenced by ESCA spectroscopy. Then, their ability to cross the BBB was assessed by the in vivo Rat Brain Perfusion Technique and, in one case, by means of a systemic administration (rat femoral vein injection). Fluorescent and confocal microscopy studies showed that while PLGA Np are unable to cross the BBB, for the first time these solid Np surface-modified with peptides were shown to be able to cross the BBB.

Animals↗

PubMed2005

Atomic force microscopy and photon correlation spectroscopy: two techniques for rapid characterization of liposomes.

The direct evaluation of the heterogeneity of the particle population of nanometric drug delivery systems as liposomes is difficult to achieve owing to the dimension and the carrier characteristics. The influence of the lipidic ratio and composition on the physical stability of liposomes during their storage was investigated using atomic force microscopy (AFM) and photon correlation spectroscopy (PCS). Liposomes were made by a mixture of different lipids and obtained using distinct methods of preparation. AFM images, acquired immediately after the deposition of the sample on mica surface, clearly showed the spherical shape of the lipidic vesicles. In all the 7 months of the experiment, the average sizes of the different liposomes evaluated using the two techniques were comparable. According to PCS analysis, AFM images confirmed that almost all the diversified vesicular systems tended to form aggregates during their storage; this loss of stability was strengthened by the increase of polydispersity index value. The different behaviours observed were to ascribe to the lipidic composition more than the methods of liposome preparation. In conclusion, AFM technique owing to the relative simplicity cold be useful for the technological control of size distribution profile according to the preparative factors and moreover to the batch-to-batch reproducibility.

Drug Carriers↗

PubMed2005

Ketorolac tromethamine liposomes: encapsulation and release studies.

Liposomes loaded with ketorolac tromethamine salt were prepared by using a thin layer evaporation method. The physical properties of liposomes were studied by using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The relationship between lipid composition, encapsulation efficiency, vesicle size, and the release of ketorolac tromethamine-loaded liposomes was studied. The drug content was found to be dependent on the lipidic composition used in the preparations and, in particular, vesicles containing both cationic lipids (dimethyldioctadecylammonium bromide and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride), and phosphatidylcholine had a higher entrapped efficiency than liposomes with phosphatidylcholine alone or in the presence of cholesterol. Finally, the cationic liposomes appear to be useful as carriers for ketorolac tromethamine to control its in vitro release.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Liposome-oligonucleotides interaction for in vitro uptake by COS I and HaCaT cells.

Liposomes are considered very promising delivery systems for antisense therapeutic approach, offering drug protection and facilitating oligonucleotide cell internalization. The present study was aimed to investigate the influence of phospholipid composition of the liposomal systems both on the encapsulation and on the oligonucleotide carrier capacity in vitro. Liposomes composed of neutral (phosphatidylcholine, cholesterol and dioleoylphosphatidylethanolamine) and/or cationic lipids (N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride salt, DOTAP) with different molar ratios were complexed with 5' fluorescein conjugated 29-mer phosphorothioate oligonucleotide (PS-ODN). The interaction was evaluated using atomic force microscopy (AFM), gel electrophoresis and HPLC analysis. Cytofluorimetric analysis and fluorescence microscopy were applied to evaluate the uptake and intracellular distribution of fluorescently labelled PS-ODN after transfection in two cell lines, COS I (fibroblast cell) and HaCaT (immortalized keratinocyte cell). The AFM studies reveal that the liposome/PS-ODN interaction leads the formation of a new irregular structure that completely hides the PS-ODN. Gel electrophoresis experiments and HPLC analysis have clearly demonstrated that also neutral liposomes are able to keep a little amount of PS-ODN but without strain to the complexation; the interaction was weak and rapidly destabilized when the complex was added to the cells. Transfection experiments performed with different incubation times show that DOTAP liposomes increase the rate of cellular uptake of PS-ODN and seem to influence its intracellular distribution in COS I cells where the oligonucleotide looks localized in nucleoli. Similar behaviour, at a lesser extent, is exhibited in HaCaT cells.

Animals↗

PubMed2005

Poor outcome in patients treated with brachytherapy for diffuse in-stent restenosis. The role of additional stenting despite prolonged antiplatelet therapy.

BACKGROUND: Brachytherapy (IBT) has been the first effective treatment of in-stent restenosis (ISR). However, when IBT is associated with additional stenting, high rates of late thrombosis have been observed. Even though prolongation of a double antiplatelet therapy seems to have overcome this problem, studies analyzing whether additional stenting still remains a negative prognostic factor for restenosis are lacking. AIM: To evaluate outcomes of patients treated for ISR with or without additional stenting and IBT followed by prolonged antiplatelet therapy. METHODS: Seventy-seven consecutive patients treated with beta radiation in 89 lesions with ISR were analyzed according to the need for deploying additional stents: 73 lesions were treated without additional stents (Group 1) and 16 lesions with one or more new stents (Group 2) because of suboptimal results or flow-limiting dissections. Double antiplatelet therapy was administered for 12 months. An angiographic follow-up was scheduled after 6 months. P-values < 0.05 were considered significant. RESULTS: Restenosis rates were 31.5% (23/73) and 62.5% (10/16) in Group 1 (G1) and Group 2 (G2), respectively (p = 0.02). The two groups did not differ for late vessel thrombosis (8 in G1 and 2 in G2). In G2, high rates of recurrence were observed in the additional stent (6/16, 37.5%; p = 0.02 versus edge restenosis and in old stent recurrence in both G1 and G2). CONCLUSIONS: The association of additional stenting with brachytherapy in treatment of ISR is characterized by poor outcomes, even if a prolonged antiplatelet therapy has been administered. These results are related to high restenosis rates observed in the additional stent.

Aged↗

PubMed2003

Chemo-enzymatic synthesis of levodropropizine.

Levodropropizine, an antitussive drug, was prepared in high enantiomeric excess in three steps, starting from dichloroacetone (2). Monosubstitution of 2 with sodium benzoate and subsequent baker's yeast reduction stereoselectively afforded the corresponding chlorohydrin in 73% ee, which was converted to levodropropizine and enantiomerically enriched up to 95% ee by fractional crystallisation.

Antitussive Agents↗

PubMed2003

MHC class II enhanceosome: how is the class II transactivator recruited to DNA-bound activators?

MHC class II (MHCII) determinants play a crucial role in the immune response by presenting antigenic peptides to T cells. Their expression is controlled from compact promoters at the transcriptional level. Pre-assembled regulatory factor X (RFX) and nuclear factor Y (NFY) complexes form a platform on DNA. The class II transactivator (CIITA) can then be recruited through multiple protein-protein interactions. In this report, we defined domains of CIITA that are responsible for its interactions with these DNA-bound factors. Furthermore, using DNA-affinity precipitation, we demonstrated that although CIITA binds at least five activators, RFX5, RFXAP, RFXANK/B, NFYB and NFYC, its assembly on the promoter requires the addition of nuclear extracts. We conclude that not only does the platform bind DNA via multiple, spatially constrained nteractions, but that it can recruit only modified and/or complexed CIITA to MHCII promoters.

Amino Acid Sequence↗

PubMed2003

Intracoronary beta-radiation for the treatment of patients at very high risk for recurrence of in-stent restenosis: a single center experience.

BACKGROUND: Intracoronary brachytherapy has significantly reduced the recurrence of in-stent restenosis. The aim of this study was to evaluate the feasibility, safety and efficacy of intracoronary beta-radiation in patients at very high risk for recurrence of in-stent restenosis. METHODS: We analyzed 42 patients with 50 lesions submitted to catheter-based beta-radiation (Beta-Cath System, Novoste Corporation, Norcross, GA, USA) for in-stent restenosis. Thirty-eight lesions were at the second restenosis, 8 at the third, and 4 at the fourth; a diffuse pattern was present in 78%. RESULTS: Balloon angioplasty was performed for 30 lesions (60%) and the cutting balloon technique for 20 (40%). In 12 lesions further 14 stents had to be deployed (28%). The delivery catheter was successfully positioned in 96% of the procedures. The mean dwell time was 179 +/- 50 s with a radiation dose ranging from 18.4 to 25.3 Gy, depending on the vessel size. A complete angiographic success without coronary dissection and without any additional stenting after radiation delivery was achieved in 86%. At follow-up (7.2 +/- 2.1 months), the overall restenosis rate was 30.4% (14 lesions). A recurrence was detected in 1/11 lesions with initial focal pattern and in 13/39 lesions with initial diffuse pattern. The restenosis rate was higher in patients in whom a geographic miss had occurred (p < 0.05 vs lesions without geographic miss) and in those in whom a new stent had been deployed (p < 0.05 vs lesions treated without a stent). CONCLUSIONS: Brachytherapy reduces the in-stent restenosis rate in patients who are at very high risk of recurrence. The restenosis pattern, geographic miss and new stent deployment seem to be negative prognostic factors for recurrence of restenosis.

Aged↗