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Biomedical subjects

G Bertoni

Publications and source records attributed to G Bertoni.

At least 19 recordsLinked to original sources
PubMed2006

Model-based quantification of EELS spectra: Including the fine structure.

An extension to model-based electron energy loss spectroscopy (EELS) quantification is reported to improve the possibility of modelling fine structure changes in electron energy loss spectra. An equalisation function is used in the energy loss near edge structure (ELNES) region to model the differences between a single atom differential cross section and the cross section for an atom in a crystal. The equalisation function can be shown to approximate the relative density of unoccupied states for the given excitation edge. On a set of 200 experimental h-BN spectra, this technique leads to statistically acceptable models resulting into unbiased estimates of relative concentrations and making the estimated precisions come very close to the Cramér-Rao lower bound (CRLB). The method greatly expands the useability of model-based EELS quantification to spectra with pronounced fine structure. Another benefit of this model is that one also gets an estimate of the unoccupied density of states for a given excitation edge, without having to do background removal and deconvolution, making the outcome intrinsically more reliable and less noisy.

Journal Article↗
PubMed2006

Impact of surgery on the development of duodenal cancer in patients with familial adenomatous polyposis.

PURPOSE: Precancerous duodenal lesions in patients with familial adenomatous polyposis can be detected with duodenoscopy and treatment may prevent the development of cancer. We proposed to determine the frequency, natural history, cumulative risk, and risk factors of the precancerous duodenal lesions in a series of patients diagnosed in northern Italy. METHODS: A prospective, endoscopic, follow-up protocol was performed in 50 patients examined by gastroduodenoscopy at two years of interval or less. The presence and severity of precancerous lesions of the duodenal mucosa were evaluated by Spigelman score. Twenty-five patients (50 percent) had proctocolectomy and ileoanal anastomosis, 15 (30 percent) had colectomy and ileorectal anastomosis, and 5 (10 percent) had proctocolectomy and definitive ileostomy from 0 to 3 years before the admission to the surveillance program. All patients showed more than a thousand adenomas in the colorectal mucosa. No patients with attenuated polyposis were found. RESULTS: At the first endoscopy, duodenal adenomas could be detected in 19 of 50 patients (38 percent), whereas at the end of the follow-up, 43 (86 percent) had duodenal lesions. The final mean Spigelman score increased during the follow-up period (P<0.001 respect to baseline values). No duodenal cancer could be detected. Eleven patients had or developed severe precancerous duodenal lesions (Stage IV) treated with endoscopic or surgical resection. The distribution of patients with Stage IV according to the surgery of the colon was: 2 of 25 treated with ileoanal anastomosis and 8 of 15 with ileorectal anastomosis (P=0.0024, Fisher's exact test). CONCLUSIONS: Patients with familial adenomatous polyposis are at risk of significant neoplasia. The natural history of precancerous lesions might be related to surgical treatment of colorectal neoplasms.

Adenoma↗
PubMed2005

Immune dysregulation in flea allergy dermatitis--a model for the immunopathogenesis of allergic dermatitis.

BACKGROUND: Flea allergy dermatitis (FAD) is a common skin disease in dogs and can be induced experimentally. It often coexists with other allergic conditions. So far no studies have investigated the quantitative production of cytokine mRNA in skin biopsies and peripheral blood mononuclear cells (PBMC) in flea allergic dogs. OBJECTIVE: The aim of our study was to improve the understanding of the immunopathogenesis of allergic dermatitis as a response to fleabites. MATERIAL AND METHODS: Allergic and non-allergic dogs were exposed to fleas. Before and after 4 days of flea exposure mRNA was isolated from biopsies and PBMC. Production of chymase, tryptase, IL-4, IL-5, IL-13, TNF-alpha and IFN-gamma mRNA was measured by real-time RT-PCR. The inflammatory infiltrate in the skin was scored semi-quantitatively. The number of eosinophils, mast cells (MC) and IgE+ cells/mm2 was evaluated to complete the picture. RESULTS: FAD was associated with a higher number of MC before flea exposure and with a significant increase of eosinophils after flea exposure as compared to non-allergic dogs. The number of IgE+ cells was higher in allergic dogs before and after flea exposure. In allergic dogs mRNA for most cytokines and proteases tested was higher before flea exposure than after flea exposure. After exposure to fleas an increased mRNA production was only observed in non-allergic dogs. In vitro stimulation with flea antigen resulted in a decreased expression of most cytokines in allergic dogs before flea exposure. In contrast, in PBMC, only increased levels of IL-4 and IL-5 mRNA were observed in allergic dogs before flea exposure. However, after flea exposure and additional stimulation with flea antigen the production of mRNA for all cytokines tested was significantly increased in allergic dogs. CONCLUSION: We demonstrated that the response in biopsies and PBMC is different and that FAD is associated with a TH2 response.

Animals↗
PubMed2005

First-principles calculation of the electronic structure and energy loss near edge spectra of chiral carbon nanotubes.

We present first principles calculations of the electronic structure of small carbon nanotubes with different chiral angles theta and different diameters (d<1 nm). Results are obtained with a full potential method based on the density functional theory (DFT), with the local density approximation (LDA). We compare the band structure and density of states (DOS) of chiral nanotubes with those of zigzag and armchair tubes with similar diameters. The carbon K-edge energy loss near edge structures (ELNES) have been studied and pi* and sigma* contributions have been evaluated. These contributions give information on the degree of hybridization for the small chiral nanotubes.

Journal Article↗
PubMed2005

Safety risks for animals fed genetic modified (GM) plants.

GM plants are widely grown all over the world, but many constraints still tend to discourage their use in Europe. Potential risks suggested to be associated with the use of GM are unexpected gene effects, allergenic potential, antibiotic resistance, gene flow. GM feed safety is presently evaluated by adopting the concept of GM substantial equivalence, by comparison with non-GM isogenic crops. Comparison is based on a wide spectrum of chemical components and on livestock performance. From the available experimental data, currently utilized GM plants appear safe and show no effects on animals or animal products. Hence, although they potentially exist, safety risks caused by the use of GM plants appear to be so low as be negligible in comparison with their potential benefits, if appropriately designed. GM plants represent a valuable option for future breeding, to increase yield while reducing the use of pesticides, improve plant adaptation to unfavourable environments, and produce better quality crops, also from a nutritional point of view. Nonetheless, GM crops are novel foods and the assessment of their safety using a scientific sound approach seems essential to protect the environment, as well as the health of humans and livestock.

Animal Feed↗
PubMed2005

Nucleotide sequence and polymorphism of the caprine major histocompatibility complex class II DQA1 (Cahi-DQA1) gene.

The major histocompatibility class II DQ molecules are dimeric glycoproteins involved in antigen presentation to CD4(+) T cells. In the current work, we have performed the molecular analysis of the goat Cahi-DQA1 gene. Sequencing of the Cahi-DQA1 cDNA revealed a single 768bp open reading frame. The alignment of this sequence with its bovine and ovine DQA1 counterparts revealed a remarkable degree of nucleotide identity (92-93% for the most similar bovine and ovine sequences). Moreover, we amplified a region including the 3'-end of intron 1, exon 2 and the 5'-end of intron 2. We identified seven Cahi-DQA1 alleles that likely correspond to four different allelic lineages. The alignment of these seven Cahi-DQA1 alleles revealed the existence of 23 amino acid polymorphic sites, seven of which (alpha(10), alpha(55), alpha(56), alpha(68), alpha(69), alpha(71) and alpha(76)) are highly polymorphic with at least three amino acid substitutions. Ten of the 23 polymorphic amino acid sites were included in the peptide binding region and consequently they might play a crucial role in immunological processes modulating disease pathogenesis.

Amino Acid Sequence↗
PubMed2005

Welfare assessment based on metabolic and endocrine aspects in primiparous cows milked in a parlor or with an automatic milking system.

An automatic milking system (AMS) was compared with a traditional milking parlor (MP) to evaluate metabolic and psycho-physiological aspects of animal welfare. Twenty Italian Friesian heifers were allocated to 2 groups of 10 cows each after calving and maintained in the same free-stall barn. The first group was milked twice daily in a MP; the second group was milked in a single box AMS. Feed and diet characteristics were analyzed. Health status and body condition score (BCS) were evaluated in each cow. Blood samples were obtained from -14 to 154 d in milk (DIM) to determine metabolic profile and basal concentrations of cortisol in plasma. Data collected from 10 cows per group were processed. No significant difference was detected in milk yield, BCS, and energy-related metabolites (glucose, nonesterified fatty acids, beta-hydroxybutyrate, and triglycerides) from cows in MP or in AMS during the first 22 wk of lactation. These results, jointly with the absence of significant differences in plasma metabolites related to protein metabolism, mineral metabolism, and liver function during the first 22 wk of lactation, indicates that cows in AMS did not suffer metabolically. Greater basal concentrations of plasma cortisol in AMS cows, even if absolute values were considered to be in an acceptable range, might indicate chronic stress in these primiparous cows. Further research is necessary to confirm this hypothesis.

3-Hydroxybutyric Acid↗
PubMed2005

Incomplete humeral condylar fracture in two English Pointer dogs.

Incomplete humeral condylar fracture was diagnosed by means of radiology, CT, scintigraphy, arthroscopy and bone biopsy in two English Pointer dogs. In both cases an acute thoracic limb lameness, unrelated to a known episode of major trauma, was observed. Incomplete humeral condylar fracture, mainly described in the Spaniel breeds, has been recently diagnosed in Labrador retrievers, Rottweiler, German Wachtel and other breeds. The pathogenesis of the condition is still unknown, but incomplete ossification of the humeral condyle and mechanical stress, alone or associated, have to be considered. However, our clinical and histopathological data lead us to believe that in Pointers, high performance dogs, the mechanical stress can assume a critical ethiopathogenetic role.

Animals↗
PubMed2004

Structural characterization of the caprine major histocompatibility complex class II DQB1 (Cahi-DQB1) gene.

The major histocompatibility class II genes have been extensively characterized in sheep and cattle, whereas in goats the only class II genes that have been completely sequenced are DRA and DRB. Herewith, we report the complete coding sequence of the goat DQB1 gene. This gene has a single open reading frame of 786bp, being organized in five exons and displaying 95-97% nucleotide identity with its bovine and ovine cDNA orthologous sequences. The structural features of the goat DQB1 molecule are well conserved with regard to its mammalian orthologues. Conserved glycosilation sites (beta19) and cysteine residues (beta15, beta79, beta117, beta173) forming disulfide bridges have been identified in the goat DQB1 molecule. The alignment of several Cahi-DQB1 exon 2 sequences has allowed to identify five different allelic variants Neighbor-joining phylogenetic analysis of caprine, ovine and bovine DQB sequences has allowed to ascertain that the five Cahi-DQB1 alleles we have found correspond to three different allelic lineages. We have identified fifteen polymorphic positions in the Cahi-DQB1 molecule, but only six of them are located in the peptide binding region. The high degree of conservation of these polymorphic sites located outside the peptide binding region in cattle and sheep suggests that they might play a functional role in antigen-presentation to CD4+ T cells.

Alleles↗
PubMed2003

The accumulation of alpha-Tocopherol and Retinol in the milk of water buffalo is correlated with the plasma levels of triiodothyronine.

Milk is the most important source of Retinol and alpha-Tocopherol for calves. These antioxidants save the food quality and prevent lipid oxidation in the mammary gland and the calf growing tissues. In Bubalus bubalis, seasonal changes for the plasma levels of both antioxidants were not found. The levels of Retinol and alpha-Tocopherol in the milk were 2 and 1.7 times higher in winter than in summer, respectively. These levels were correlated with the plasma level of triiodothyronine, and markedly increased in cows injected with triiodothyronine in summer. The cytosol from alveolar epithelial cells of mammary glands was incubated with alpha-Tocopherol and 3H-Retinol and, after gel filtration chromatography, both antioxidants were found associated with proteins migrating as a single peak of 33 kD. The amount of alpha-Tocopherol and Retinol binding proteins was 1.5 and 2.3 times higher in winter than in summer respectively. The Retinol binding proteins migrated as two bands (33 and 16 kD) by electrophoresis in denaturing and reducing conditions. Our data suggest that triiodothyronine enhances the transport of both liposoluble antioxidants through the blood-mammary barrier, and demonstrate that proteins of the mammary epithelial cells are involved in such a transport.

Animals↗
PubMed2001

Characterization of caprine interleukin-4.

Caprine interleukin-4 (IL-4) cDNA was cloned from RNA of mitogen stimulated goat peripheral blood mononuclear cells utilizing reverse transcriptase-polymerase chain reaction. The sequence of caprine IL-4 cDNA corresponds to a 535 nucleotide mRNA with 5'- and 3'-untranslated regions and a 405 nucleotide open reading frame, the first 66 nucleotides of which encode a putative signal peptide. Mature IL-4 is a 12.8kDa protein containing six cysteine residues and two potential N-linked glycosylation sites and is highly homologous with other ruminant IL-4. The predicted molecular mass of mature unglycosylated IL-4 was confirmed by western blot of recombinant caprine IL-4 expressed in bacteria with a monoclonal antibody against a carboxyterminal peptide derived from the predicted amino acid sequence of bovine IL-4. Eukaryotic expression plasmids containing caprine IL-4 cDNA were used to characterize recombinant IL-4. Transcription of IL-4 mRNA was confirmed by transfection of COS-7 and goat synovial membrane cells, and recombinant IL-4 produced by stably transfected L929 cells inhibited inducible nitric oxide synthase in macrophages. Genetic immunization of mice with a caprine IL-4 cDNA expression plasmid induced antibodies against recombinant caprine IL-4 produced in bacteria.

Amino Acid Sequence↗
PubMed2001

Evolution of catabolic pathways and metabolic versatility in Pseudomonas stutzeri OX1.

Pseudomonas stutzeri OX1 is able to degrade toluene and ortho-xylene via the direct oxygenation of the aromatic ring. The genetic studies carried out suggest that the genes coding for the monooxygenase involved in the early steps of this catabolic route have been acquired by gene transfer. P stutzeri OX1 is also potentially able to utilize meta- and para-xylene as growth substrates. These two isomers are metabolized through a different pathway (TOL pathway). Both catabolic routes can be activated or inactivated by means of genomic rearrangements. The relevance of such recombination mechanisms in the evolution and the adaptability of P. stutzeri is discussed.

Biodegradation, Environmental↗
PubMed2001

Porcine dendritic cells generated in vitro: morphological, phenotypic and functional properties.

Despite the central role that dendritic cells (DC) play in immune regulation and antigen presentation, little is known about porcine DC. In this study, two sources of DC were employed. Bone marrow haematopoietic cell-derived DC (BM-DC) were generated using granulocyte-macrophage colony-stimulating factor (GM-CSF) in the presence or absence of tumour necrosis factor-alpha (TNF-alpha). Monocyte-derived DC (Momicron-DC) were generated with GM-CSF and interleukin-4 (IL-4). In both systems, non-adherent cells developed with dendritic morphology, expressing high levels of major histocompatibility complex (MHC) class II. The presence of TNF-alpha increased the BM-DC yield, and enhanced T-cell stimulatory capacity. Both BM-DC and Momicron-DC expressed the pan-myeloid marker SWC3, as well as CD1 and CD80/86, but were also CD14+ and CD16+. The CD16 molecule was functional, acting as a low-affinity Fc receptor. In contrast, the CD14 on DC appeared to differ functionally from monocyte CD14: attempts to block CD14, in terms of lipopolysaccharide (LPS)-induced procoagulant activity (PCA), failed. The use of TNF-alpha or LPS for DC maturation induced up-regulation of MHC class II and/or CD80/86, but also CD14. Allogeneic mixed leucocyte reactions and staphylococcal enterotoxin B antigen presentation assays demonstrated that these DC possessed potent T-cell stimulatory capacity. No T helper cell polarization was noted. Both the BM-DC and the Momicron-DC induced a strong interferon-gamma and IL-4 response. Taken together, porcine DC generated in vitro possess certain characteristics relating them to DC from other species including humans, but the continued presence of CD14 and CD16 on mature and immature porcine DC was a notable difference.

Animals↗
PubMed2001

Producing specific milks for speciality cheeses.

Protected denomination of origin (PDO) cheeses have distinctive sensorial characteristics. They can be made only from raw milk possessing specific features, which is processed through the 'art' of the cheesemaker. In general, the distinctive sensorial traits of PDO cheese cannot be achieved under different environmental-production conditions for two main reasons: (1) some milk features are linked to specific animal production systems; (2) cheese ripening is affected by the interaction between milk (specific) and the traditional technology applied to the transformation process (non-specific). Also, the environment for a good ripening stage can be quite specific and not reproducible. With reference to milk, factors of typicality are species and/or breed, pedoclimatic conditions, animal management system and feeding. Other factors that influence cheese quality are milk treatments, milk processing and the ripening procedures. The technology applied to most cheeses currently known as PDO utilizes only raw milk, rennet and natural lactic acid bacteria, so that milk must be, at its origin, suitable for processing. The specific milk characteristics that ensure a high success rate for PDO cheeses are high protein content and good renneting properties, appropriate fat content with appropriate fatty acid composition and the presence of chemical flavours originating from local feeds. Moreover, an appropriate microflora is also of major importance. The factors that contribute to achieving milk suitable for transformation into PDO cheese are genetics, age, lactation stage, season and climate, general management and health conditions, milking and particularly feeding, which affect nutrient availability, endocrine response and health status, and also the presence of microbes and chemical substances which enrich or reduce the milk-cheese quality. Many of these factors are regulated by the Producer Associations. However, the secret of the success of PDO cheeses is the combination of modern technology and tradition, with the objective of adapting the product to market demand, without losing specificity, originality and authenticity.

Animals↗
PubMed2001

New insights into the activation of o-xylene biodegradation in Pseudomonas stutzeri OX1 by pathway substrates.

The regulation of the tou operon of Pseudomonas stutzeri OX1, for degradation of toluene and o-xylene via phenolic intermediates, has been faithfully reconstructed in vitro with purified proteins. The set-up included the prokaryotic enhancer-binding protein TouR, the sigma54-dependent PToMO promoter and the sigma54-containing RNA polymerase. With this system we prove that direct binding of 2-methylphenol (o-cresol) to TouR is the only regulatory step for activation of PToMO in response to aromatic effectors, thereby ruling out the involvement of other factors or a need for protein processing. In addition, we found that while TouR failed entirely to activate PToMO in the absence of inducers, the protein had per se a very significant ATPase activity, which was only moderately increased by o-cresol addition. The results presented here support the view that TouR-like proteins are particularly suitable as evolutionary assets to endow recently evolved pathways for the degradation of environmental pollutants with an optimal degree of transcriptional regulation.

Adenosine Triphosphatases↗