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Roberto Pallini, Eduardo Fernandez, Liverana Lauretti, Francesco Draicchio, Vito E. Pettorossi, Carlo Gangitano, Aurora Del Fà, Corrado Olivieri-Sangiacomo and Alessandro Sbriccoli

✓ In adult guinea pigs, the oculomotor nerve was sectioned proximally (at the tentorial edge) or more distally (at the orbital fissure) and immediately repaired by reapproximation. During a 24-week postoperative period, extrinsic eye motility was assessed by analyzing the vestibulo-ocular reflexes. The regenerated oculomotor nerve was studied morphometrically on semi-thin histological sections at 16 and 24 weeks postinjury. The selectivity of muscle reinnervation was investigated by injection of both single (horseradish peroxidase) and double (fluorescent dyes) retrograde axonal tracers into the eye muscles. Following proximal repair of the oculomotor nerve, the degree of recovery of extraocular motility varied among different animals and remained stable over long-term observations. In animals with poor recovery, aberrant eye movements were always found, and the somatotopic map of the reinnervated eye muscles was greatly altered. Distortions of the central representation were also seen in those animals in which a good level of functional recovery was seen. However, in animals with good recovery, a topographic bias was re-established by about 65% of the original neuronal population, as opposed to 26% in the animals with poor recovery. Neurons located contralateral to the axotomized nucleus sprouted intra-axially and projected their axons to denervated eye muscles. The number and diameter of the regenerated axons, the number and soma diameter of the axotomized neurons, and the ratio of distal axonal branches to proximal supporting neurons were all related to the degree of functional recovery.

Following repair of the oculomotor nerve at the orbital fissure, extraocular motility had recovered in all of the animals at 16 weeks without aberrant phenomena. Functional regeneration of the distally transected oculomotor nerve is thought to be the result of selective muscle reinnervation.

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Roberto Pallini, Eduardo Fernandez, Liverana Lauretti, Elisabetta Dell'Anna, Frank La Marca, Carlo Gangitano, Aurora Del Fà, Corrado Olivieri-Sangiacomo, Alessandro Sbriccoli and Gian Franco Rossi

✓ The superior cervical ganglion (SCG) has been grafted to the brain of adult rats in an attempt to reverse the parkinsonian syndrome that follows destruction of central dopamine systems. However, the main limitation to this approach is the massive cell death that occurs in the grafted SCG after direct transplantation into the brain.

In adult rats, 6-hydroxydopamine (6-OHDA) was stereotactically injected into the right substantia nigra (SN). One month later, dopamine denervation was assessed using the apomorphine-induced rotational test. In rats with a positive test, an autologous peripheral nerve (PN) graft was tunneled from the right cervical region to the ipsilateral parietal cortex. One end of the PN graft was sutured to the transected postganglionic branch of the SCG and the other end was inserted into a surgically created cortical cavity. The apomorphine test was repeated at 3 days and again at 1, 3, and 5 months after surgery. The brain, SCG, and PN graft were studied under light and electron microscopy and with the tyrosine hydroxylase immunohistochemical and horseradish peroxidase tracing methods.

Three days after grafting, there were no significant differences on the apomorphine test as compared to the preoperative test. Conversely, 1, 3, and 5 months after grafting, the number of rotations was reduced by 69% (± 20.2), 66.6% (± 17.1), and 72.5% (± 11.3), respectively. Control rats that received a free PN graft to the brain and underwent section of the postganglionic branch of the SCG did not show significant changes on the apomorphine test after surgery. Histological examination revealed that the PN graft was mostly reinnervated by amyelinic axons of small caliber. Approximately 40% of the SCG neuronal population that normally projects to the postganglionic branch survived axotomy and regenerated the transected axons into the PN graft. Axons arising from the SCG elongated the whole length of the graft, crossed the graft—brain interface and extended into brain regions adjacent to the denervated striatum up to 2037 µm from the graft insertion site.

This work shows that the ingrowth of catecholamine-regenerating axons from the SCG to dopamine-depleted brain parenchyma significantly reduces behavioral abnormalities in hemiparkinsonian rats. This effect cannot be ascribed either to the brain cavitation or to the PN tissue placement in the brain.

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Roberto Pallini, Angelo Tancredi, Patrizia Casalbore, Delio Mercanti, Luigi M. Larocca, Alessandro Consales, Liverana Lauretti and Eduardo Fernandez

The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 102. At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)-like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth-stimulatory mechanism that involved an EGF-like factor.

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Roberto Pallini, Angelo Tancredi, Patrizia Casalbore, Delio Mercanti, Luigi M. Larocca, Alessandro Consales, Liverana Lauretti and Eduardo Fernandez

✓ The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 102. At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)—like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth—stimulatory mechanism that involved an EGF-like factor.

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Eduardo Fernandez, Alessandro Di Rienzo, Enrico Marchese, Luca Massimi, Liverana Lauretti and Roberto Pallini

✓ An 18-year-old man presented with a spontaneously occurring radial nerve palsy that spared the triceps muscle. At surgery, the portion of the radial nerve located at the midarm level had an hourglass-like appearance. Under magnification, an external—internal neurolysis of the narrowed portion of the hourglass-shaped portion revealed nerve torsion. Straightening of the twisted nerve and fixation accomplished using epiperineurium—fascia stitches to avoid a new torsion resulted in complete functional recovery of the radial nerve.

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Roberto Pallini, Lauretti Liverana, Larocca Luigi Maria, Colosimo Cesare, Fernandez Eduardo and Ramesh Babu

✓ Although the craniocervical junction is involved in a variety of conditions including trauma, neoplastic lesions, and inflammatory processes, isolated inflammatory conditions involving the occipital condyle exclusively are not known. The authors report this unusual condition in two cases. Unless the patient is of poor medical risk, excision of the lesion is the treatment of choice to decompress the neural structures.

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Luca Denaro, Federico Di Rocco, Marco Gessi, Libero Lauriola, Liverana Lauretti, Roberto Pallini, Eduardo Fernandez and Giulio Maira

✓ Chordoid meningioma is a rare meningothelial tumor characterized by chordoma-like histological features with lymphoplasmacellular infiltration. This tumor is often seen in children, but not in adults, with a systemic inflammatory syndrome (iron-resistant microcytic anemia and/or dysgammaglobulinemia) and very rarely with a persistent moderate hyperthermia.

In the present report the authors describe a temporal chordoid meningioma in a 30-year-old woman who presented with fever, headache, and a serological inflammatory syndrome. The clinical symptomatology, chiefly the fever, disappeared immediately after removal of the tumor. To the authors' knowledge, only one similar patient with such clinical presentation and response to surgery has been mentioned in the literature. Interestingly, at immunohistochemical examination, the neoplasm showed focal positivity for the pyrogenic cytokine interleukin-6. The capacity of the tumor to produce this pyrogenic cytokine could explain both the patient's clinical presentation and her response to the surgical management.