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Biomedical subjects

G Brunelli

Publications and source records attributed to G Brunelli.

At least 55 records · Page 3Linked to original sources
PubMed1988

Experimental repair of spinal cord lesions by grafting from CNS to PNS.

Based on the previous work of other researchers, we first removed 1 cm of the spinal cord of rats and grafted the gap with peripheral nerve. We obtained progression of regenerating axons inside the grafts, but regrowing axons halted at the distal cord level. We then tried directly to connect the cephalad stump of the cord with the sciatic nerve, several surgical models of which have been previously studied. The latest model uses a homologous sciatic nerve of an inbred Wistar rat, to bridge the gap between the lateral bundle of the cord, proximal to the origin of the sciatic roots, and the sciatic trunk distal to the fusion of its roots. Good reinnervation of the sciatic nerve and distal muscles was found. It was demonstrated by: a) the remyelination of regenerated nerve fibers, not only in the grafts but also in the sciatic nerve; b) re-innervation of motor endplates; and c) clinical and electromyographic muscle responses. Central nervous system (CNS) neurons are able to regenerate not only their axons through the CNS but also into peripheral nerves. The capacity of CNS neurons to neurotize peripheral nerves reaching terminal organs, is a basic finding. Many questions arise from the study, including: Can these results be extrapolated to humans? What would be the function of these regenerated fibers that might lack some of the control mechanisms peculiar to peripheral nerves?

Animals↗
PubMed1988

Trapeziometacarpal stabilisation in arthrosis.

The trapeziometacarpal (TM) joint is often the site of painful arthrosis, particularly in women at the onset of the fourth decade. It is generally associated with capsuloligamentous laxity of the joint or with work requiring the repetitive use of the thumb and index finger and thus work which is typically done by women. It may also be of traumatic origin following joint fracture, but this is not discussed in the present paper. The treatment of this syndrome by stabilisation of the joint is described.

Adult↗
PubMed1987

Chemotactic arrangement of axons inside and distal to a venous graft.

Experiments in rats, introducing the proximal and distal stumps of tibial and sural nerves into a vein graft, showed by acetylcholinesterase and toluidine blue staining that sensory and motor fibers mix inside the vein graft, but that nevertheless they are able to select their distal targets correctly. The authors' hypothesis is that surface membrane antigens of Schwann cells might be responsible for this chemotactic phenomenon.

Animals↗
PubMed1987

A comparison of vascularized and nonvascularized bone transfer in rabbits: a roentgenographic, scintigraphic, and histologic evaluation.

Extensive bone defects caused by bone tumor resection, osteomyelitis, congenital pseudoarthrosis, post-traumatic bone loss, or femoral head necrosis, require large bone grafts. Such large defects usually are not amenable to conventional, nonvascularized cancellous grafts. By using vascularized bone grafts that do not undergo creeping substitution, that heal rapidly and are not depending on the surrounding tissue, better, safer, and faster results can be obtained. To compare recoveries after vascularized grafts with those after conventional, nonvascularized grafts, experiments were carried out in a rabbit model. They demonstrated good viability and better and faster healing of the microvascular grafts, using radiography, scintigraphy, light microscopy of bone osteocytes and vessels, and tetracycline double-labeling evaluation techniques.

Animals↗
PubMed1987

PGD2 induces pulmonary hyperresponsiveness to acetylcholine in vivo in the guinea-pig.

1 A threshold dose of Prostaglandin D2 (PGD2) (0.5 microgram/kg i.v.), which did not modify the basal values of airway resistance, potentiated the acetylcholine induced bronchospasm in anaesthetized guinea-pigs. 2 beta-adrenoreceptors blockade induced by propranolol enhanced the positive interaction between PGD2 and acetylcholine in the pulmonary dynamics. 3 Active sensitization of guinea-pigs by ovalbumin increased the pulmonary PGD2-acetylcholine interaction and the phenomenon was sustained during the time. 4 The inability of PGD2 to potentiate histamine-induced bronchoconstriction suggests a specificity for the interaction.

Acetylcholine↗
PubMed1987

Interference of the new antiinflammatory compound flunoxaprofen with eicosanoid formation in various biological systems.

S-(+)-2-(4-Fluorophenyl)-alpha-methyl-5-benzoxazolacetic acid (flunoxaprofen, Priaxim is a new antiinflammatory compound, which in various biological systems interferes with the generation and release of arachidonic acid metabolites of the cyclo-oxygenase pathways without affecting the formation of 5- and 12-lipoxygenase products. Flunoxaprofen reduces the concentration of thromboxane (TX)B2 (ED50 = 35.4 mg/kg p.o.) and prostaglandin (PG)E2-like activity (ED50 = 39.9 mg/kg p.o.) in the inflammatory exudate of rats 8 h after implantation of sponges soaked with carrageenan, whereas the concentration of leukotriene (LT)B4 remains in the range of that of the untreated animals (3.1 ng/ml). Flunoxaprofen inhibits cell infiltration in the exudate and this suggests that LTB4 does not initiate cell recruitment but may represent a mechanism for amplifying the inflammatory response. Using human platelets challenged with collagen, flunoxaprofen only at higher concentration (10(-4) mol/l) reduces TXB2 formation without altering generation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid. This suggests a low capacity of flunoxaprofen of affecting platelet aggregation regulated by arachidonic acid metabolites. Flunoxaprofen prevents pulmonary changes due to secondary release of TXA2 in the guinea-pig. In fact this drug prevents changes due to immunological reaction and antagonizes bronchoconstriction due to exogenous administration of histamine and LTC4.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Prostaglandin D2 (PGD2) potentiates cholinergic responsiveness in guinea-pig trachea.

PGD2 dose dependently potentiated the parasympathetic-induced contraction in guinea-pig trachea in vitro. This phenomenon was much more evident in ovalbumin-sensitized guinea-pig trachea. Indomethacin pretreatment enhanced the capacity of PGD2 to potentiate cholinergic-induced contraction in normal but not in ovalbumin-sensitized guinea-pig. PGD2 shifted to the left the curve of the exogenous acetylcholine-induced contraction in guinea-pig trachea, indicating a postsynaptic site of action of PGD2. These data suggest a role of PGD2 in the genesis of hyperreactivity of tracheal smooth muscles, particularly in a model of pulmonary anaphylaxis.

Acetylcholine↗
PubMed1986

Possible involvement of eicosanoids in the pharmacological action of bromelain.

Bromelain, a proteolytic enzyme extracted from pineapple plants, was investigated for its capacity to interfere with arachidonic acid metabolism, since prostaglandins and other eicosanoids are well-known to be involved in the pathogenesis of inflammatory diseases. Bromelain was tested for its ability to interfere with eicosanoids generation in vivo in two experimentally-induced inflammatory reactions in the rat. Also antiplatelet aggregation activity of bromelain was studied in ex vivo rat platelets. The results seem to indicate an interference of bromelain with arachidonic acid cascade, which, however, deserves further investigation to be better assessed.

Animals↗
PubMed1986

Lumbar puncture and febrile convulsions.

We report the data of 878 selected children between 1 month and 6 years, presenting a first episode of seizure with fever. Two-hundred-fifty-five children underwent lumbar puncture. In 7 cases the CSF findings showed a bacterial meningitis, in 14 cases a viral meningitis. In 598 of the 623 children who did not undergo LP, a bacterial meningitis could be excluded on the basis of the clinical course. The data show that the probability of finding a bacterial or viral meningitis is high in children under 6 months of age even if no significant neurological signs are found on examination performed shortly after the seizure. In our study, older children affected by bacterial meningitis were clinically identifiable. In children aged 6 months to 3 years without important neurological signs, a complex seizure has been found to be a significant discriminating factor between patients with and without viral meningitis.

Child↗
PubMed1985

Problems in nerve lesions surgery.

An overview of the concepts on peripheral nerve regeneration and of research on the progress in this field is carried out. Problems of regeneration and factors influencing it, both improving and worsening it, are considered, especially with respect to the clinical treatment of nerve lesions. Classical techniques of repair (sutures and grafts) as well as very new methods (e.g., direct muscular neurotization) are discussed. Postoperative treatment and result evaluation are presented.

Humans↗
PubMed1985

Positive interaction between leukotriene C4 and histamine and other mediators on vascular tissues.

The interaction of leukotriene C4 (LTC4) with the contractile activity of histamine (H), serotonin (5HT) and norepinephrine (NE) has been investigated in isolated vascular preparations. Threshold concentration of LTC4 (5 X 10(-9) M) significantly potentiated the vasoconstricting effect of these compounds on guinea-pig pulmonary artery (GPPA). This phenomenon was long-lasting for H since it was still present 40 min after LTC4 had been washed. FPL-55712 (10(-5) M) counteracted the increased H response on GPPA induced by LTC4. Potentiation of H activity due to LTC4 was also observed on guinea-pig thoracic aorta (GPTA) indicating that LTC4-induced hyperreactivity is not a phenomenon restricted to the pulmonary vascular bed. In the experiments carried out in presence of indomethacin (3 X 10(-6) M), LTC4 still potentiated H-induced vasoconstriction on GPPA, however the time course of the phenomenon was significantly shorter than that observed in absence of the cyclooxygenase inhibitor. The contractile activity of H and NE on guinea-pig portal vein (GPPV) was not potentiated by LTC4. These results demonstrate that LTC4 induces hyperreactivity of the arterial vascular tissue to vasoactive compounds and suggest that cysteinyl-leukotrienes may have pathological significance in the hemodynamic changes occurring during anaphylactic reactions. Preliminary experiments carried out on human intralobar pulmonary artery strongly support this hypothesis.

Anaphylaxis↗
PubMed1985

Direct muscular neurotization.

Direct muscular neurotization has limited indications: loss of the distal stump of a motor nerve or avulsion of the "neural" part of one or more muscles. These lesions cannot be repaired with conventional microsurgery techniques, and without the presented technique, the denervated muscles will remain permanently paralyzed. Despite rare failures from poor local vascular or muscular conditions, direct muscular neurotization has provided the vast majority of good results, with scores similar to those obtained with good microsurgical sutures or grafts and has been adopted by several microsurgeons.

Animals↗
PubMed1985

[Muscular elementarization in the "borderline" replantation and revascularization of the forearm].

In order to avoid the risks of local and general complications encountered in replantations after long ("critical") periods of ischemia, or in cases of severe open fractures with crushed muscles, a so-called "muscle elementarization" technique has been devised. This technique consists of removing the muscular masses which have undergone prolonged ischemia with a priority for the least important muscles. In this manner, we believe that edema and the consequent risks of compartment syndromes as well as of life threatening complications can be reduced. Functional impairment is limited as well. Eleven cases of severe crushing or critical time limit ischemia replantation have been treated in this manner without any complications.

Forearm↗
PubMed1985

Surgical treatment of actinic brachial plexus lesions: free microvascular transfer of the greater omentum.

Actinic brachial plexus lesions after mastectomy have been treated in 67 cases. Thirty-nine cases have been operated on, 31 of which by means of a free microvascular transfer of the greater omentum. Indications and contraindications of the procedure are discussed, as well as the types of anatomic-pathologic lesions that have been found, and the surgical technique that has been modified and improved over time is presented. Results indicate that free microvascular greater omentum transfer following neurolysis is currently the best method for relief of pain.

Arm↗
PubMed1984

Experimental foetal microsurgery as related to myelomeningocele.

To study this capacity of embryono-foetal tissue to regenerate without scar formation, experimental intrauterine surgery has been carried out in rabbits. This study has been performed with regard to the possibility of using intrauterine microsurgery to correct myelomeningocele in humans to avoid scar adhesion between the medulla and the growing vertebral bones and subsequent hydrocephalus. Lesions were produced in the spinal cord of rabbit foetuses, and observation after birth showed repair without scar formation. Further research is in progress to confirm these findings and to adapt this procedure to the clinical situation.

Animals↗