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Biomedical subjects

L Bertini

Publications and source records attributed to L Bertini.

At least 19 recordsLinked to original sources
PubMed2005

Current fluctuations in stochastic lattice gases.

We study current fluctuations in lattice gases in the macroscopic limit extending the dynamic approach for density fluctuations developed in previous articles. More precisely, we establish a large deviation theory for the space-time fluctuations of the empirical current which include the previous results. We then estimate the probability of a fluctuation of the average current over a large time interval. It turns out that recent results by Bodineau and Derrida [Phys. Rev. Lett. 92, 180601 (2004)]] in certain cases underestimate this probability due to the occurrence of dynamical phase transitions.

Journal Article↗
PubMed2005

Determination of microbial volatile organic compounds from Staphylococcus pasteuri against Tuber borchii using solid-phase microextraction and gas chromatography/ion trap mass spectrometry.

The mycelium of Tuber borchii Vittad., a commercial truffle species, is used as a model system for in vitro ectomycorrhizal synthesis, infected seedling production and biotechnological applications. Our fungal cultures were accidentally contaminated with a Staphylococcus pasteuri strain, showing a strong antifungal activity against T. borchii mycelium. In order to identify the antifungal volatile agents produced by S. pasteuri, solid-phase microextraction (SPME) with gas chromatography and mass spectrometry (GC/MS) was used. Using this method 65 microbial volatile organic compounds (MVOCs), synthesized by this bacterium in either single or in fungal-bacterial dual culture, were identified. SPME combined with GC/MS may be a useful method for the determination of MVOCs involved in the antifungal activity. These results showed that bacteria with unusual biological activities could be a major problem during large-scale production of inoculum for truffle-infected seedling.

Fungi↗
PubMed2004

[Imaging update in geriatric oncology].

The cancer is a problem that plagues all the ages but the greater part of the malignant tumors hits the old persons. The more elevated incidence sites of primary tumor in geriatrical age are the prostate, the lung and the colon-rectum in the men and the breast, the colon-rectum, the lung and the stomach in the women. The imaging has made steps of giant in the last few decades, with the introduction of new equipment and methodical news so as to assure everybody early and accurated diagnosis. For the lung carcinoma great advantages have been bring to us with the introduction of CT-PET and the multislice CT, that has concurred the execution of virtual bronchoscopy. The virtual endoscopy has been applied with happening also in the screening of the carcinoma of colon-rectum, executed through CT or MR. New MR technologies have allowed perform spectroscopic studies in such organs as prostate and breast, bringing the biochemical diagnosis beyond that morphologic. The MR then turns out fundamental in the appraisal of the Patient with bone metastases thanks also to the new whole body examinations. Finally the recent technology has allowed the execution of multiorgan CT screening bringing in this way new possibilities but also new questions.

Aged↗
PubMed2004

[Neuroimaging of Alzheimer disease: current role and future potential].

Alzheimer disease (AD), the most common cause of dementia in the elderly, is a progressive neurodegenerative disorder, associated with deterioration in cognition and behaviour. With the availability of newer drugs for symptoms treatments there is a general agreement to the need of an early diagnosis and an the development of new sensitive tools, to identify and/or monitor early cerebral changes, suggestive for AD. CT and MRI are recommended for routine evaluation, in order to exclude treatable causes of dementia and to exactly evaluate the degree of cerebral atrophy and the presence of parenchymal signal abnormalities. Functional imaging, including PET, SPECT and functional MR techniques, are able to investigate physiological cerebral function, such as blood perfusion, metabolism, activation, molecular composition and water diffusibility, and have the potential to detect subtle pathological changes earlier during course of disease. MRI can provide both an accurate morphological assessment and a functional evaluation. Further investigations are needed to precisely define which will be the role of the different MR techniques. Most likely an exhaustive evaluation of AD will include information obtained by conventional and functional imaging, combined with clinical, laboratory and genetic findings.

Alzheimer Disease↗
PubMed2003

Thrombelastography. Present and future perspectives in clinical practice.

RESULTS: Thrombelastography (TEG) is a method for evaluating the viscoelastic properties of the blood clot, from its formation to its lysis. All major surgeries may be associated with massive blood loss, with blood component transfusion therapy often becoming mandatory. The clinician's goal is thus to optimize and possibly minimize blood components usage. To this end, TEG allows for a qualitative and dynamic analysis of the specific blood clotting process, from clot formation through its lysis, highlighting alterations at every single step in the cascade. With TEG is thus possible to know if bleeding is due to a failure to provide adequate surgical hemostasis, if there is platelet dysfunction, or to detect anomalies in coagulation proteases or their inhibitors, or if the blood loss is associated to early, excessive fibrinolysis. The theoretical advantages of TEG are the ease of performing the test, the fast sample reading times (now 30 minutes) and the informative

Blood Coagulation↗
PubMed2002

Posterior subgluteal approach to block the sciatic nerve: description of the technique and initial clinical experiences.

BACKGROUND AND OBJECTIVE: A new posterior approach to the sciatic nerve in the subgluteal region was developed. We describe our clinical experiences on 135 consecutive patients. METHODS: All blocks were performed with a nerve stimulator (stimulation frequency 2 Hz; intensity from 1 reduced to < or = 0.5 mA before application). A line was drawn from the greater trochanter to the ischial tuberosity of the femur; then, from the mid-point of this line, a second line was drawn perpendicularly and extended caudally for 4 cm: the end of this line represented the entry point of the needle. Sciatic stimulation was elicited at < or = 0.5 mA; then ropivacaine 0.75% 20 mL was injected. An independent observer recorded the time from needle insertion to successful sciatic nerve stimulation (performance time), the depth of appropriate sciatic stimulation and the number of needle redirections, as well as the quality of nerve block, the discomfort during the procedure and patient acceptance. RESULTS: The performance time was 41 +/- 25 s (mean +/- SD) and the mean (SD) depth at which the sciatic nerve stimulation was found was 45 +/- 10 mm. The median (range) number of needle redirections required to find the proper sciatic stimulation was 2 (1-5). The tibial response was observed in 77 patients (57%), while the common peroneal response was observed in 58 patients (43%). The degree of discomfort reported was very low and only 16 patients (12%) reported severe pain during placement of the block. The onset time (mean +/- SD) of sensory and motor block was 7 +/- 4 and 17 +/- 13 min respectively, and the surgical procedure was completed with only the peripheral nerve block in 127 patients (94%). The same anaesthesia procedure was acceptable by 127 patients (94%) and only eight patients (6%) would prefer a different anaesthesia technique in the future. CONCLUSIONS: The study demonstrated that the sciatic nerve can be easily blocked using this new posterior subgluteal approach, suggesting that it represents a safe and effective alternative to block the sciatic nerve at a proximal level, with the potential for reducing the discomfort experienced by the patient during block placement.

Adult↗
PubMed2001

Fluctuations in stationary nonequilibrium states of irreversible processes.

We formulate a dynamical fluctuation theory for stationary nonequilibrium states (SNS) which covers situations in a nonlinear hydrodynamic regime and is verified explicitly in stochastic models of interacting particles. In our theory a crucial role is played by the time reversed dynamics. Our results include the modification of the Onsager-Machlup theory in the SNS, a general Hamilton-Jacobi equation for the macroscopic entropy and a nonequilibrium, nonlinear fluctuation dissipation relation valid for a wide class of systems.

Journal Article↗
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

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

Postoperative analgesia by combined continuous infusion and patient-controlled epidural analgesia (PCEA) following hip replacement: ropivacaine versus bupivacaine.

BACKGROUND: Ropivacaine is a new local anaesthetic, which compared to bupivacaine is less toxic and shows greater sensory and motor block dissociation. We hypothesised that treatment of postoperative pain with a combined regimen of continuous epidural infusion and Patient-Controlled Epidural Analgesia (PCEA) using ropivacaine could have given better results compared with those we had obtained using bupivacaine. METHODS: Patients undergoing total hip replacement were randomly assigned to two groups. They received epidural analgesia for postoperative pain treatment using ropivacaine, 2 mg x ml(-1) or bupivacaine 2 mg x ml(-1). Both drugs were administered as a constant infusion of 6 ml x h(-1) supplemented by PCEA bolus doses of 2 ml. Patients in both groups received morphine intravenously on demand from a patient-controlled analgesia (PCA) device. An independent observer recorded pain scores, intensity of motor block and morphine consumption at regular intervals during the first 24 h after surgery. RESULTS: Fifty-one patients were evaluated. Ropivacaine and bupivacaine, in similar amounts, provided similar results assessed as adequate to very good postoperative analgesia, whereas motor block was significantly more intense in patients treated with bupivacaine. CONCLUSIONS: Despite similar analgesic effects, epidural infusion of ropivacaine combined with PCEA provides higher patient satisfaction than equal doses of bupivacaine due to lack of motor block.

Aged↗
PubMed2001

A new posterior approach to the sciatic nerve block: a prospective, randomized comparison with the classic posterior approach.

UNLABELLED: To evaluate the efficacy and acceptance of a new posterior subgluteus approach to the sciatic nerve, as compared with the classic posterior approach, 128 patients undergoing foot orthopedic procedures were randomly allocated to receive either the classic posterior sciatic nerve block (Group Labat, n = 64) or a modified subgluteus posterior approach (Group subgluteus, n = 64). All blocks were performed with the use of a nerve stimulator (stimulation frequency, 2 Hz; intensity, 1-0.5 mA). In Group subgluteus, a line was drawn from the greater trochanter to the ischial tuberosity; then, from the midpoint of this line, a second line was drawn perpendicularly and extended caudally for 4 cm. The end of this line represented the needle entry. In both groups, a proper sciatic stimulation was elicited at 0.5 mA; then 20 mL of 0.75% ropivacaine was injected. The time from needle insertion to successful sciatic nerve stimulation was 60 s (range, 10-180 s) with the Labat's approach and 32 s (range, 5-120 s) with the new subgluteus approach (P = 0.0005). The depth of appropriate sciatic stimulation was 45 +/- 13 mm (mean +/- SD) after 2 (range, 1-7) needle redirections in Group subgluteus and 67 +/- 12 mm after 4 (range, 1-10) needle redirections in Group Labat (P = 0.0001 and P = 0.00001, respectively). The failure rate was similar in both groups. Severe discomfort during the procedure was less frequent and acceptance better in Group subgluteus (5 patients [8%] and 60 patients [94%], respectively) than in Group Labat (20 patients [31%] and 49 patients [77%], respectively) (P = 0.0005 and P = 0.005, respectively). We conclude that this new subgluteus posterior approach to the sciatic nerve is an easy and reliable technique and can be considered an effective alternative to the more traditional Labat's approach. IMPLICATIONS: Evaluating the efficacy and acceptance of a new approach to the sciatic nerve block, this prospective, randomized study demonstrated that the new subgluteus posterior approach is an easy and reliable technique and can be considered an useful alternative to the more traditional Labat's approach in patients undergoing foot surgery, facilitating the performance of the sciatic nerve blocks.

Adult↗
PubMed2001

Thrombophilic risk factors in patients with central retinal vein occlusion.

Few and contrasting data are available on the prevalence of hemostatic risk factors in patients with central retinal vein occlusion (CRVO). Aim of this study was to investigate the metabolic and inherited risk factors for venous thrombosis in 100 CRVO patients (age: 59 yrs; range 18-77) and in 100 controls (age: 56 yrs; range 18-84). In patients homocysteine (Hcy) levels were significantly higher than in controls and were affected by the C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism (p < 0.001). The prevalences of activated protein C resistance (APCR), factor V Leiden positivity, elevated PAI-1 and Lp(a) levels were significantly higher in patients with respect to controls. At multivariate analysis, only hyperhomocysteinemia (OR 11, 95% CI 3.6-36.2; p < 0.0001) and elevated PAI-1 levels (OR 8.9, 95% CI 3.5-41.3; p < 0.01), in addition to hypertension (OR 40.5, 95% CI 8.6-188.8; p < 0.00001) and hypercholesterolemia (OR 3.1, 95% CI 1.6-20.5; p < 0.05), were independent risk factors for CRVO. These data demonstrate a potential role of hemostatic risk factors in the pathophysiology of CRVO.

Adolescent↗