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Biomedical subjects

M E Gentili

Publications and source records attributed to M E Gentili.

At least 19 recordsLinked to original sources
PubMed2004

Contralateral effect of amitriptyline and bupivacaine for sciatic nerve block in an animal model of inflammation.

BACKGROUND: Using a carrageenan inflammation rat model, we evaluated two experimental approaches to prolong sciatic nerve block on contralateral hyperalgesia. Method. We performed ipsilateral sciatic nerve block on the inflamed hind paw with bupivacaine-loaded microspheres suspended in dexamethasone (bupivacaine 12.5 mg) and with amitriptyline (6.25 and 12.5 mg) as ultralong-acting local anaesthetics. Bupivacaine (1.25 mg) was used as long-acting local anaesthetic and saline was used as a control. The sixth group received amitriptyline 6.25 mg intraperitoneally (n=10 for each group). RESULTS: The duration of ipsilateral nerve block was 2 h for bupivacaine, 7 h for amitriptyline 6.25 mg, 11 h for amitriptyline 12.5 mg and 21 h for bupivacaine-loaded microspheres in suspension with dexamethasone. Whereas contralateral hyperalgesia was not observed during block produced by bupivacaine-loaded microspheres, contralateral hyperalgesia was observed with sciatic nerve block using amitriptyline. CONCLUSIONS: Because of the differential effect observed on the contralateral side, the mechanism underlying the prolongation of ipsilateral block with amitriptyline may not result only from a prolonged Na(+) channel blockade but might be explained by a local toxic effect or lack of systemic actions.

Amitriptyline↗
PubMed2002

Clinical perception of phantom limb sensation in patients with brachial plexus block.

BACKGROUND AND OBJECTIVE: Patients' perception of limb position during regional anaesthesia is frequently incorrect. The incidence and nature of this phenomenon has not yet been completely described. The aim of this prospective study was to assess phantom sensation in patients undergoing a brachial plexus block. METHODS: Axillary block was performed in 81 patients with the aid of a peripheral nerve stimulator. Immediately after the block, patients were allocated randomly to two groups (Group 1, n = 40; Group 2, n = 41) to have the blocked limb placed either on their thorax or in abduction. Fifteen minutes later, when the block was complete, the position of the limb was changed, without the knowledge of the patient, to a new position of abduction and flexion of the forearm. Patients were questioned about the new limb position. Fifteen minutes later, the limb was then transiently shown to the patient and further placed 'blindly' to another position. Patients were once more questioned about this new position. RESULTS: Correct perception was more frequently observed in both groups following the first interview. Thirty-two and 34 patients gave at least one erroneous response about their limb position when it was initially placed on the thorax or in abduction respectively. Transient visualization of the limb position did not improve the rate of correct response. CONCLUSIONS: Patients' perception of the position of the limb after axillary block in the majority of instances was probably due to persisting sensory inputs from the shoulder joint, which is not involved in this block. This is in contrast to supraclavicular or interscalene blocks. A significant number of patients experienced phantom limb sensation. They reported an arm position in fact related to the position of their arm before the axillary block.

Adolescent↗
PubMed2001

Lack of peripheral analgesia mediated by intraplantar administration of neostigmine in carrageenan-injected rats.

BACKGROUND AND OBJECTIVE: The aim of the study was to test the peripheral analgesic action of neostigmine. Intraplantar administration of neostigmine was studied in carrageenan-injected rats. METHODS: After assessing baseline values (T0) for paw circumference and the paw withdrawal threshold on both hind paws, the right hind paw was injected with 0.2 mL of 1% carrageenan and the left hind paw with 0.2 mL of saline (0.9% NaCl). Two hours later (T1), both hindpaws were tested for inflammation (paw circumference) and for hyperalgesia (paw withdrawal threshold) and subsequently 20 microg of neostigmine was injected in the right hind paw. The paw withdrawal threshold was tested again 10 (T2), 20 (T3) and 60 min (T4) and paw circumference 60 min (T4) after neostigmine injection. RESULTS: Carrageenan injection in the right hindpaw was associated with a decrease in the paw withdrawal threshold reflecting mechanical hyperalgesia (P < 0.001) and an increase in paw circumference reflecting oedema (P < 0.001) in the right hind paw when compared with the left side from T1 to T4. Neostigmine had no effect on paw circumference and the paw withdrawal threshold at measuring points T2, T3 and T4 when compared with T1 in the right hindpaw. CONCLUSION: Our results support the lack of peripheral analgesic effect of neostigmine.

Analgesics↗
PubMed2000

Successful epidural blood patch in a patient with headache for 6 months after lumbar root decompression.

Prolonged headache following dural puncture is an uncommon problem that may occur after a spinal tap, often as a complication of epidural anaesthesia. This problem has also been described after long-term epidural or spinal anaesthesia, myelography or spinal surgery. A case of prolonged postdural puncture headache following lumbar nerve root decompression is described in a healthy young man. No other cause could be found either clinically or with the aid of scanning by computerized tomography or magnetic resonance imaging techniques at the spinal level involved. The symptoms were successfully treated with an epidural blood patch performed seven months following the original surgical operation.

Adult↗
PubMed1999

The effect of a sciatic nerve block on the development of inflammation in carrageenan injected rats.

UNLABELLED: Neurogenic inflammation may participate in postoperative inflammatory pain. We evaluated, in the rat, the influence of a short and prolonged sciatic nerve block on carrageenan-induced inflammation, the time course of which may be compared to postoperative inflammation. A catheter was placed on the right sciatic nerve and injected with 0.5% bupivacaine with epinephrine (0.2 mL): one injection in the Short Block Group, and four injections performed at 90-min intervals in the Prolonged Block Group. In all groups, the two hind paws were then injected with carrageenan. The development of inflammation was evaluated in both hind paws by measurement of paw circumference (PC) before, and 1, 2, 3, 4, 6, and 24 h after carrageenan injection. Temperature of both hind paws was evaluated at the same time points. The vocalization threshold to paw pressure test (VTPP) of both hind paws was evaluated at 6, 8, 10, 12, and 24 h after carrageenan injection. The left hind paw was used for the Control Group. A Sham Group had a catheter placed on the sciatic nerve and injected with normal saline. Inflammation developed in the Control Group with a maximum increase of PC (32%) and temperature (14%) 4 h after carrageenan injection and a maximal reduction of VTPP (44%) at 6 h, reflecting mechanical allodynia. A similar evolution was observed in the Sham Group. In the Short Block Group, the nerve block did not influence the PC, the paw temperature, or the VTPP when compared with the Control Group. In the Prolonged Block Group, when compared with the Control Group, the increased PC was reduced throughout the 24 h (P < 0.0001). The maximal increase in PC at 4 h was limited to 23%, as compared with the precarrageenan value. This effect on PC did not persist at 24 h. Paw temperature was increased (P = 0.07) throughout the study in the Prolonged Block Group, as compared with the Control Group. The VTPP reduction was still limited in the Prolonged Block Group at 24 h, as compared with the Control Group (P < 0.0001). We conclude that a prolonged sciatic nerve block limits carrageenan-induced increase in PC and, subsequently, mechanical allodynia at 24 h in rats. IMPLICATIONS: Our study has shown that a prolonged (6 h) but not a short sciatic nerve block (90 min) can limit edema and related pain after carrageenan-induced inflammation in rat.

Anesthetics, Local↗
PubMed1994

[Headache and low back pain after epidural anesthesia].

Headache and low back pain are common minor complications after epidural anaesthesia. Headache is due to cerebrospinal leakage through the site of accidental dural puncture. Epidural blood patch is considered as the better curative treatment. Acute or long term backache is often reported after epidural anaesthesia. Different mechanisms are suggested: needle trauma, myotoxicity of local anaesthetic and postural problem. Large prospective randomized studies are yet necessary to clarify the role of epidural anaesthesia, the duration of symptoms and the therapeutic.

Adult↗