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Biomedical subjects

L Bertini

Publications and source records attributed to L Bertini.

At least 19 recordsLinked to original sources
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↗
PubMed2001

[Continuous brachial plexus blockade for shoulder surgery].

Continuous brachial plexus block is the technique of choice for postoperative shoulder pain treatment. The localization of the plexus is usually obtained drawing landmarks on the skin and using the electrical nerve stimulator; these and other different modalities are applied in order to reach safely and precisely nerve roots to be blocked with an anaesthetic solution. The Author presents a new anatomical perspective to guide the localization of the brachial plexus. It is shown how it is possible to detect the pathway of the brachial plexus from the cutaneous surface, linking between each other various landmarks: a) the apex of the scalene triangle, at the cross of a line leaving from the cricoid process and directed posterior to the posterior border of the sternocleidomastoid muscle, b) the midline of the clavicle c)the deltoid-pectoral sulcus d) the midpoint between the coracoid process and the chest profile e) the pulsation of the artery in the axylla. Following the guide of the so formed anesthetic line, is possible to place the needle, with a direction from distal to proximal, in a tangential route towards the interscalenic groove, thus allowing to perform a block of the plexus in a simple and efficacious way.

Brachial Plexus↗
PubMed2001

[Peripheral blocks for the lower limb: lumbar plexus].

BACKGROUND: The techniques of continuous peripheral blockades have shown to be efficient in postoperative pain control, in the various orthopaedic procedures of the limbs. The aim of this study is to evaluate the existing data about the use of a continuous blockade of the lumbar plexus or femoral nerve, together with the indications for technique and therapy. METHODS: We considered the principal results of prospective, randomised studies described in literature about the assessment of a continuous peripheral blockade of the lumbar plexus or the femoral nerve in limb surgery. Furthermore we described the principal techniques for positioning the perinerval catheters in the considered sites, and the advised dosage regimen. RESULTS: The various studies report an adequate costs/benefits relation concerning the used techniques. The analysed studies not only report an adequate efficacy of the postoperative pain control, but often show an important benefit in terms of functional recovery of the operated limbs and on final outcome of the patient. CONCLUSIONS: The use of continuous blockades of the lumbar plexus or femoral nerve shows to be an important and effective instrument not only in terms of positive effects on postoperative pain control, but also in terms of relevant advantages concerning final outcome after surgery. Nevertheless these techniques should not be considered as the only approach to postoperative pain in the orthopaedic patient, but have to be included in a global, multidisciplinary and multimodal approach.

Humans↗
PubMed2001

Continuous peripheral block in foot surgery.

Peripheral neural blockade techniques are commonly used procedures to provide perioperative anesthesia and analgesia. Several continuous infusion catheter techniques have been described to extend the use of peripheral neural blockade into the postoperative period as an effective method of providing pain management. The analgesic benefit of continuous local anesthetic peripheral block in the management of postoperative pain is primarily related to the properties of providing intense analgesia thereby reducing perioperative opioid requirements and opioid-related side effects and promoting early recovery of postoperative activity. Continuous peripheral nerve blockade seems to be effective in allowing major foot and ankle surgery to be done particularly on an outpatient basis with greater pain relief. The sciatic nerve is the largest nerve in the body and it lies deep in the posterior thigh. According to its anatomy, the sciatic nerve can then be reached at different levels from the parasacral space to the popliteal fossa, ideally identifying a sciatic line running from the inferior border of the gluteus maximus muscle between the greater throcanter and the ischiatic tuberosity to the popliteal fossa. A variety of continuous peripheral blocks have been described in this paper including continuous sciatic block at several levels (para-sacral nerve block, subgluteal sciatic nerve block) and popliteal nerve block.

Foot↗
PubMed2001

Pain free hospital: organisation aspects.

The rational approach to acute pain management is to use the highest quality evidence available. Acute pain management is more than a collection of interventions. It is a package of care that needs to be examined as a whole as well as in its parts. In the context of acute pain management, this comes from systematic reviews of valid randomised trials. We still have to adapt to the circumstances of the individual, but our policies will be more discerning. Acute pain is not confined to postoperative wards but it is a problem in many clinical settings. Educational programs for allied health professionals are equally important because they play the key role in the management of acute pain. Accreditation and educational programs in individual institutions would enable the nurses to identify their learning needs, to acquire appropriate knowledge and skills to ensure that they are adequately prepared for the responsibilities involved in pain management. The key of successful pain management is education, not new drugs or high-tech delivery systems. Existing tools can do the job if doctors and nurses are educated, both to dispel the myths and misconceptions and to take responsibility for providing pain control. It is much easier to dispel myths when you have the evidence. In 1846, the first anaesthetic provided pain-free surgery - 150 years later patients should not have to endure unrelieved pain anywhere in the hospital.

Evidence-Based Medicine↗
PubMed2001

[Technical difficulties in epidural blocks and spinal bleeding complications].

The clinical cases of two patients with neurological complications following neuroaxial blocks are reported. The events took place in different institutions where thousands of central blocks were yearly performed. In both instances the blocking procedures presented technical difficulties needing repeated lumbar punctures. The first case concerns a patient receiving anticoagulant and fibrinolytic therapy for vascular pathology. This 89 year-old female experienced severe cord compression requiring surgical decompression and laminectomy. The second case regards a patient with previous minor surgical procedure requiring postoperative antiinflammatory treatment. This 74 year-old male experienced subarachnoid hemorrhage and spinal/epidural hematoma as shown by NMR. The symptoms regressed with steroid therapy. The authors emphasise the risks of mechanical trauma of epidural or spinal anesthesia both during positioning or removal of an epidural catheter. The problem related to the compatibility between central blocks and antithrombotic/anticoagulant prophylaxis/therapy is now of primary concern and has led to publications about guide lines on this topic. If central block is carried out in patients with bleeding diathesis it is mandatory to co-ordinate multidisciplinary assistance for early detection of significant symptoms of the above described complications and subsequent treatment.

Aged↗
PubMed2000

Unilateral bupivacaine spinal anesthesia for outpatient knee arthroscopy. Italian Study Group on Unilateral Spinal Anesthesia.

PURPOSE: To compare unilateral and conventional bilateral bupivacaine spinal block in outpatients undergoing knee arthroscopy. METHODS: One hundred healthy, premedicated patients randomly received conventional bilateral (n = 50) or unilateral (n = 50) spinal anesthesia with 8 mg hyperbaric bupivacaine 0.5%. A lateral decubitus position after spinal injection was maintained in unilateral group for 15 min. Times from spinal injection to readiness for surgery, block resolution, and home discharge were recorded. RESULTS: Three patients in each group were excluded due to failed block. Readiness for surgery required 13 min (5 - 25 min) with bilateral and 16 min (15 - 30) with unilateral spinal block (P = 0.0005). Sensory and motor blocks on the operated limb were T9 (T12 - T2) with a Bromage score 0/1/2/3: 0/2/0/45 in the unilateral group and T7 (T12 - T1) with Bromage score 0/1/2/3: 4/1/6/36 with bilateral block(P = 0.026 and P = 0.016, respectively). Vasopressor was required only in five bilateral patients (P = 0.02). Two segment regression of sensory level and home discharge required 81+/-25 min and 281+/-83 min with bilateral block, and 99+/-28 min and 264+/-95 min with unilateral block (P = 0.002 and P = 0.90, respectively). CONCLUSION: Seeking unilateral distribution of spinal anesthesia provided more profound and longer lasting block in the operated limb, less cardiovascular effects, and similar home discharge compared with bilateral spinal anesthesia, with only a slight delay in preparation time.

Adult↗