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Biomedical subjects

L Leonardi

Publications and source records attributed to L Leonardi.

At least 19 recordsLinked to original sources
PubMed2006

Long-term outcomes in liver transplant patients with hepatic C infection receiving tacrolimus or cyclosporine.

Choice of calcineurin inhibitor may be a contributing factor to deteriorating patient and graft survival following liver transplantation for hepatitis C virus (HCV). In our multicenter, open-label LIS2T study, de novo liver transplant patients stratified by HCV status were randomized to cyclosporine or tacrolimus. Follow-up data were obtained in an observational study of 95 patients. Mean follow-up was 34 and 37 months, respectively, for cyclosporine-treated (n = 47) and tacrolimus-treated (n = 48) patients. In patients not receiving antiviral therapy, 22 of 31 given cyclosporine (72%) and 24 of 29 given tacrolimus (83%) had biochemical recurrence of HCV. In 68 patients with at least one biopsy, histological evidence of HCV-related hepatitis was present in 27 of 31 (87%) cyclosporine-treated patients and 37 of 37 (100%) tacrolimus-treated patients (P = .02, chi-square test). Three-year actuarial risk of fibrosis stage 2 was 66% with cyclosporine and 90% with tacrolimus; for fibrosis stage 3 or 4 it was 46% and 80%, respectively. Three graft losses were attributed to HCV recurrence in cyclosporine-treated patients and six in tacrolimus-treated patients. Tacrolimus may be associated with increased risk of histological HCV disease recurrence compared to cyclosporine.

Adult↗
PubMed2006

Linezolid as rescue drug: a clinical case of soft tissue infection caused by a Staphylococcus aureus strain resistant in vivo to teicoplanin.

The authors report and discuss a patient admitted to intensive care unit (ICU) for acute respiratory failure due to upper airway obstruction caused by face and neck soft tissue infection. An oxacillin-resistant Staphyloccoccus aureus was isolated from necrotic skin lesions and from skin biopsy. The strain was susceptible in vitro to teicoplanin, but it showed resistance in vivo, despite appropriate dosage. After 6 days of full dose therapy, since the clinical course worsened, teicoplanin was interrupted and linezolid was started. In 48 hours signs of infection regressed, and the patient was discharged from the ICU after 10 days of linezolid treatment. Linezolid resulted as a rescue drug for a life-threatening infection.

Acetamides↗
PubMed2005

Biological fixation of endosseous implants.

Primary implant stability is ensured by a mechanical fixation of implants. However, during implant healing a biological anchorage is necessary to achieve final osseointegration. Aim of this study was to investigate the histological aspects of biological fixation around titanium screws. Forty-eight titanium screws with different surfaces (smooth, plasma sprayed, sand blasted) were inserted in tibiae and femura of sheep and analyzed by light microscope and SEM 1 hour, 14 and 90 days after implantation. One hour after implantation the implant-bone gap was filled with a blood clot and host bone chips arising from burr surgical preparation or friction during implant insertion. Fourteen days after implantation new trabecular bone and enveloped bone chips were observed in the gap: no osteogenesis developed where implant threads were in contact with host bone. Ninety days after surgery all trabecular bone and most of the bone chips were substituted by a mature lamellar bone with few marrow spaces. Our results suggest that the trabecular bone and bone chips represent a three-dimensional network ensuring a biological implant fixation in all different implant surfaces 2 weeks after surgery. Host bone chips could favour the peri-implant osteogenesis. Inter-trabecular and implant-trabecular marrow spaces of both trabecular and lamellar bone may favour the peri-implant bone turnover.

Animals↗
PubMed2002

Fusion of the distal sesamoid and distal phalanx in a yearling colt.

This paper describes a rare malformation of the distal portion of the left foredigit of a 15-month-old half-bred colt which was severely lame. Radiological, pathological and tomographic studies revealed hypoplasia of the metacarpophalangeal skeleton, absence of the distal sesamoid and deformation of the distal phalanx. Morphological analysis of the lesion and computerised measurement of the width of the articular surface of the distal phalanx suggested an early fusion between the distal sesamoid and distal phalanx.

Animals↗
PubMed2001

Recombinant wheat antifungal PR4 proteins expressed in Escherichia coli.

PR proteins are soluble and host-coded molecules with antifungal activity induced by a variety of agents. Wheat contains several PR proteins and among them are those of the class 4 coded wheatwin1 and wheatwin2; the two native proteins have been isolated from wheat kernel and the coding cDNA clones have been recently characterized. Herein, we report the expression of recombinant wheatwin1 and wheatwin2 in Escherichia coli-insoluble fractions; a new protocol for the purification in high yields and correct processing of the two proteins was developed. The recombinant proteins have molecular weights identical to that of the native proteins, indicating that the removal of the N-terminal methionine and cyclization of glutamine to pyroglutamate was complete. Both recombinant proteins inhibited in vitro the growth of Fusarium culmorum exhibiting antifungal properties similar to those of the native proteins.

Antifungal Agents↗
PubMed2001

A basic peroxidase from wheat kernel with antifungal activity.

A basic heme-peroxidase (WP1) was purified to homogeneity from wheat (Triticum aestivum) kernels. The protein was not glycosylated and exhibited a molecular mass of 36 kDa and a pI of 8.0. The N-terminal amino acid sequence revealed a very high similarity with a wheat flour peroxidase allergen associated with baker's asthma. WPI showed indole-3-acetic acid oxidase activity in the presence of Mn2+ and phenolic cofactors. Antifungal assays performed in vitro towards phytopathogenic fungi indicated that WP1 was active in inhibiting germ tube elongation. This first report on antifungal properties of a heme-peroxidase gives experimental support to the idea that peroxidases play a defensive role against invading pathogens.

Amino Acid Sequence↗
PubMed2001

Near infrared spectroscopic assessment of hemodynamic changes in the early post-burn period.

Near infrared reflectance spectroscopy and imaging was used to assess non-invasively the hemodynamic changes that occur in the early post-burn period in cutaneous burn injuries of varying depth. An acute porcine model was used to demonstrate the potential of near infrared spectroscopy and imaging to accurately determine the change in tissue oxygenation, blood volume and tissue water content following a thermal injury. Near infrared spectroscopy was used to monitor tissue at discrete locations, while spectroscopic imaging was able to survey large areas of tissue. Both methods were rapid and non-invasive. Tissue hemoglobin oxygen saturation, total hemoglobin and tissue water content were all affected by thermal injury and changed significantly over a 3 h post-burn monitoring period. Burns that ranged in severity between superficial and full thickness displayed a significantly different hemodynamic response. When the early post-burn profiles (1-3 h) of tissue hemoglobin oxygen saturation, total hemoglobin and tissue water content were considered jointly, injuries leading to superficial, intermediate partial thickness, deep partial thickness and full thickness burns could all be differentiated at high statistical significance. These results suggest that non-invasive hemodynamic monitoring in the early post-burn period using near infrared spectroscopy may be of value in the early assessment of burn injury.

Animals↗
PubMed2001

Isolation and amino acid sequence of two new PR-4 proteins from wheat.

We have purified and characterized two new pathogenesis-related (PR) proteins from wheat belonging to the PR-4 family. We named the proteins wheatwin3 and wheatwin4 in analogy with the previously characterized wheatwin1 and wheatwin2. Their isoelectric points were 7.1 and 8.4, respectively. We determined the complete amino acid sequence of both proteins by a rapid approach based on the knowledge of the primary structures of the homologous wheatwin1 and wheatwin2. Wheatwin3 differs from wheatwin1 in one substitution at position 88, while wheatwin4 differs from wheatwin2 in one substitution at position 78. The secondary structure and solvent accessibility of these residues were determined on the three-dimensional model of wheatwinl. Residue 88 was very accessible and was located in a flexible region. Preliminary results indicate that, like wheatwin1 and wheatwin2, wheatwin3 and wheatwin4 have antifungal activity.

Alkylation↗
PubMed2001

Experimental trichinellosis in fallow-deer (Dama dama L.).

Herbivora can play a very important role in spreading trichinellosis, as showed by the massive epidemics in man, caused by the consumption of horse meat in the last years. In this context, the present study has been undertaken to verify, through an experimental infection, the susceptibility, together with other biological parameters, of fallow-deer to Trichinella infection. The four animals, 8-9 months of age and 18-25 Kg body weight, were orally infected with low doses of Trichinella britovi and T. pseudospiralis (2,000 larvae/animal). After day 30 p.i., the animals were necropsied and, using artificial digestion methods, larval burden of Trichinella in muscle tissues was determined. Histopathological, serological (IgG monoclonal blocking ELISA) and biochemical data were assessed during the experiment. The results showed the susceptibility of fallow-deer to T. britovi and T. pseudospiralis infection; under the same inoculum size, the number of larvae/g was higher in group infected with T. britovi. The animals showed a higher immunological response to T. pseudospiralis infection. The results are discussed.

Animals↗
PubMed2001

Susceptibility of nutria (Myocastor coypus) to Trichinella infection: biological aspects.

Experimental infections with three different species of Trichinella in nutria in order to evaluate the susceptibility and the role of these rodents in the spreading of parasitosis in nature were carried out. The nutria is present in many italian wet areas and its distribution is expanding. The nutria meat is utilized as food in different countries and is retained responsible for trichinellosis in man. Two groups of ten animals were infected per os with 500 and 5,000 (n. 10) infective larvae of T. britovi; an additional study was arranged with two groups of animals infected with 5,000 larvae of T. spiralis and T. pseudospiralis, respectively. After 45 days, all animals were slaughtered and samples of different muscles were processed by standard artificial digestion and by routine histological methods. Serological investigations (specific IgG) have been carried out on sera samples by employing a monoclonal blocking ELISA. The animals showed a significant susceptibility to the infection with all species of tested Trichinella and immunological reactivity. Data obtained are discussed.

Animals↗
PubMed1999

Probing the modelled structure of wheatwin1 by controlled proteolysis and sequence analysis of unfractionated digestion mixtures.

We set up a method to get rapid information on the three-dimensional structure of peptide and proteins of known sequence. Both native and alkylated polypeptide is hydrolyzed with a number of proteases at different digestion times and the resulting mixtures are compared by HPLC analysis to establish the differences in the hydrolysis pathways of the folded and unfolded molecule. Then, the unfractionated digestion mixtures of the native polypeptide are submitted to automatic sequence analysis to identify the hydrolysis sites. The sequence of each fragment present in the mixtures is reconstructed and its amount determined by quantitative data of the sequence analyses. We used this approach to determine the amino acid surface accessibility of wheatwin1, a pathogenesis-related protein from wheat, and constructed a predictive three-dimensional model based on the knowledge of the tertiary structure of barwin, a highly homologous protein from barley. The procedure allowed us to quickly identify and quantify the hydrolysis at the susceptible bonds which could be classified as exposed, partially hidden, or inaccessible. The results were useful to evidentiate and discuss concordances and differences between experimental and model predicted accessibilities of amino acid residues. Proteins 1999;36:192-204.

Alkylation↗
PubMed1999

Radiation protection in radioguided surgery of breast cancer.

The protocols for sentinel lymph node biopsy and radioguided occult lesion localization could potentially be of great value in the management of breast cancer patients. Both involve the injection of a 99Tcm-labelled radiopharmaceutical close to or into the lesion, localization of the sentinel lymph node or occult lesion by scintigraphy, and surgical removal with the aid of a hand-held gamma-ray detector. We present dosimetric data on patients and hospital personnel involved in these procedures. For evaluation of radiation protection, we measured the absorbed dose and air kerma rate. Activity levels in excised tissues and surgical instruments were also determined. For patients, the mean absorbed dose to the abdomen was 0.45 mGy, which is low compared to doses received from other diagnostic examinations. For surgeons after 100 operations, the mean absorbed dose to the hands was 0.45 mGy and the mean effective dose 0.09 mSv. Absorbed doses to all hospital personnel involved in the procedures were very low compared to recommended annual limits stipulated by the International Commission on Radiological Protection. We conclude that these procedures, performed according to protocols laid down by the European Institute of Oncology, Milan, are safe from the point of view of radiological protection and that only routine precautions are necessary.

Breast Neoplasms↗
PubMed1999

Isolation and characterisation of wheat cDNA clones encoding PR4 proteins.

Two cDNA clones encoding the previously characterised PR4 proteins wheatwin 1 and wheatwin2 from wheat (Triticum aestivum cv. S. Pastore) have been identified and named wPR4a and wPR4b, respectively. The clones have been isolated by screening a cDNA library with a specific cDNA probe obtained by RT-PCR. The wPR4a and wPR4b cDNAs contain open reading frames of 441 and 447 bp that encode for wheatwin1 and wheatwin2, respectively.

Amino Acid Sequence↗
PubMed1999

Efficacy of two techniques for endodontic instrumentation.

The aim of the present study was to compare the quality of preparation in curved and straight root canals employing 2 techniques, i.e. the step-back technique and the technique of Goerig, Michelich and Schultz. One hundred and thirty single-rooted human teeth were employed throughout. The walls of the root canals of these teeth were painted. Following instrumentation the roots were sectioned longitudinally. The sections were observed under a stereoscopic microscope SZ40 with a grid fitted in the eyepiece. The efficacy of instrumentation was evaluated using area of paint removed as the end-point. Statistical significance of the data was tested with the chi square test employing the Epi Info 5 software. There was no statistically significant difference between techniques for straight canals. The technique of Goerig, Michelich and Schultz was more effective than the step-back technique in the apical third of curved canals.

Chi-Square Distribution↗
PubMed1998

Sentinel node localization in cutaneous melanoma: lymphoscintigraphy with colloids and antibody fragments versus blue dye mapping.

In stage I cutaneous melanoma, biopsy of the first tumour-draining lymph node (sentinel node, SN) may replace routine elective lymph node dissection (ELND). The patent blue dye (PBD) technique has been shown to be an original method for the localization of the SN, but its sensitivity is sometimes unsatisfactory, depending on the basin where the SN is located. We compared three methods to locate the SN: intraoperative PBD mapping, lymphoscintigraphy (LS) with an aspecific tracer (colloid) and LS with a specific tracer (monoclonal antibody, MoAb). Fifty patients with cutaneous melanoma were enrolled in this study. The day before surgery LS was performed following an intradermal injection of 55 MBq technetium-99m-labelled HSA colloidal particles (25 patients: group A) or 220 MBq of 99mTc-F(ab')2 MoAb 225.28 S (25 patients: group B) around the site of the primary lesion. In group B an equal amount of tracer was injected, as a control, in the contralateral site. Early and delayed images were acquired with a gamma camera and SN(s) marked on the skin. In all 50 patients the PBD technique was also performed immediately before surgery. When a blue node was identified intraoperatively, its radioactivity level was measured with a gamma probe. In the absence of blue coloration, the probe alone was used to detect the SN. Lymphoscintigraphic visualization of SNs was possible in 50/50 patients (100%), a total of 73 SNs (38 in group A and 35 in group B) were found, distributed in 55 basins. Gamma probe detection (GPD) allowed the identification of SNs in 49/50 patients (98%), and 72 SNs in 54 basins were localized. By contrast, using PBD, SNs were stained only in 40/50 patients (50 SNs in 40 basins). A tumour-positive SN was histologically proven in 13 patients (26%). In group B, no increase uptake was observed in the seven positive SNs (6/25 patients) compared with the contralateral uninvolved nodes. In conclusion this study demonstrates that LS combined with GPD is a safe method for detecting SNs and is more sensitive than the PBD technique. The use of MoAb fragments did not show any advantage over the non-specific tracer.

Adolescent↗
PubMed1998

Collagen fibril arrangement and size distribution in monkey oral mucosa.

Collagen fibre organisation and fibril size were studied in the buccal gingival and hard palate mucosa of Macacus rhesus monkey. Light and electron microscopy analysis showed connective papillae exhibiting a similar inner structure in the different areas examined, but varying in distribution, shape and size. Moving from the deep to surface layers of the buccal gingival mucosa (free and attached portions), large collagen fibril bundles became smaller and progressively more wavy with decreasing collagen fibril diameter. This gradual diameter decrease did not occur in the hard palate mucosa (free portion, rugae and interrugal regions) where the fibril diameter remained constant. A link between collagen fibril diameter and mechanical function is discussed.

Animals↗