G-quadruplex ligand RHPS4 radiosensitizes glioblastoma xenograft in vivo through a differential targeting of bulky differentiated- and stem-cancer cells

BACKGROUND

Glioblastoma is the most aggressive and most lethal primary brain tumor in the adulthood. Current standard therapies are not curative and novel therapeutic options are urgently required. Present knowledge suggests that the continued glioblastoma growth and recurrence is determined by glioblastoma stem-like cells (GSCs), which display self-renewal, tumorigenic potential, and increased radio- and chemo-resistance. The G-quadruplex ligand RHPS4 displays in vitro radiosensitizing effect in GBM radioresistant cells through the targeting and dysfunctionalization of telomeres but RHPS4 and Ionizing Radiation (IR) combined treatment efficacy in vivo has not been explored so far.

METHODS

RHPS4 and IR combined effects were tested in vivo in a heterotopic mice xenograft model and in vitro in stem-like cells derived from U251MG and from four GBM patients. Cell growth assays, cytogenetic analysis, immunoblotting, gene expression and cytofluorimetric analysis were performed in order to characterize the response of differentiated and stem-like cells to RHPS4 and IR in single and combined treatments.

RESULTS

RHPS4 administration and IR exposure is very effective in blocking tumor growth in vivo up to 65 days. The tumor volume reduction and the long-term tumor control suggested the targeting of the stem cell compartment. Interestingly, RHPS4 treatment was able to strongly reduce cell proliferation in GSCs but, unexpectedly, did not synergize with IR. Lack of radiosensitization was supported by the GSCs telomeric-resistance observed as the total absence of telomere-involving chromosomal aberrations. Remarkably, RHPS4 treatment determined a strong reduction of CHK1 and RAD51 proteins and transcript levels suggesting that the inhibition of GSCs growth is determined by the impairment of the replication stress (RS) response and DNA repair.

CONCLUSIONS

We propose that the potent antiproliferative effect of RHPS4 in GSCs is not determined by telomeric dysfunction but is achieved by the induction of RS and by the concomitant depletion of CHK1 and RAD51, leading to DNA damage and cell death. These data open to novel therapeutic options for the targeting of GSCs, indicating that the combined inhibition of cell-cycle checkpoints and DNA repair proteins provides the most effective means to overcome resistance of GSC to genotoxic insults.

Metabolic/Proteomic Signature Defines Two Glioblastoma Subtypes With Different Clinical Outcome

Glioblastoma (GBM) is one of the deadliest human cancers. Because of the extremely unfavorable prognosis of GBM, it is important to develop more effective diagnostic and therapeutic strategies based on biologically and clinically relevant subclassification systems. Analyzing a collection of seventeen patient-derived glioblastoma stem-like cells (GSCs) by gene expression profiling, NMR spectroscopy and signal transduction pathway activation, we identified two GSC clusters, one characterized by a pro-neural-like phenotype and the other showing a mesenchymal-like phenotype. Evaluating the levels of proteins differentially expressed by the two GSC clusters in the TCGA GBM sample collection, we found that SRC activation is associated with a GBM subgroup showing better prognosis whereas activation of RPS6, an effector of mTOR pathway, identifies a subgroup with a worse prognosis. The two clusters are also differentiated by NMR spectroscopy profiles suggesting a potential prognostic stratification based on metabolic evaluation. Our data show that the metabolic/proteomic profile of GSCs is informative of the genomic/proteomic GBM landscape, which differs among tumor subtypes and is associated with clinical outcome.

Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities

Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with (137)Cs photons and with protons or C-ions of 62 MeV u(-1) in the dose range of 5-40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality.

Type-3 metabotropic glutamate receptors negatively modulate bone morphogenetic protein receptor signaling and support the tumourigenic potential of glioma-initiating cells

Targeted-therapies enhancing differentiation of glioma-initiating cells (GICs) are potential innovative approaches to the treatment of malignant gliomas. These cells support tumour growth and recurrence and are resistant to radiotherapy and chemotherapy. We have found that GICs express mGlu3 metabotropic glutamate receptors. Activation of these receptors sustained the undifferentiated state of GICs in culture by negatively modulating the action of bone morphogenetic proteins, which physiologically signal through the phosphorylation of the transcription factors, Smads. The cross-talk between mGlu3 receptors and BMP receptors was mediated by the activation of the mitogen-activated protein kinase pathway. Remarkably, pharmacological blockade of mGlu3 receptors stimulated the differentiation of cultured GICs into astrocytes, an effect that appeared to be long lasting, independent of the growth conditions, and irreversible. In in vivo experiments, a 3-month treatment with the brain-permeant mGlu receptor antagonist, LY341495 limited the growth of infiltrating brain tumours originating from GICs implanted into the brain parenchyma of nude mice. While clusters of tumour cells were consistently found in the brain of control mice, they were virtually absent in a large proportion of mice treated with LY341495. These findings pave the way to a new non-cytotoxic treatment of malignant gliomas based on the use of mGlu3 receptor antagonists.

Primary hemorrhagic intramedullary melanoma. Case report with emphasis on the difficult preoperative diagnosis

Primary melanoma of the central nervous system (CNS) is rare and primary spinal melanoma (PSM) is even more unusual. Preoperative diagnosis of melanocytic lesion as a PSM is difficult, because of the heterogeneous magnetic resonance (MR) signal intensity, due to hemorrhagic foci and melanin deposits. We describe the case of a 68 year-old male with a MR showing at Th8-Th9 level a well-defined intramedullary lesion; for the characteristics of hemorrhagic signal on MR and its association with a presumptive brain cavernoma, a preoperative diagnosis of intramedullary cavernous angioma was suspected. Pathological examination revealed a melanoma, and for the absence of other localizations outside the spinal cord, a diagnosis of primary spinal melanoma was established. The growth of PSM is slower and survival is longer than in the most common spinal metastasis from skin melanoma. Patients who undergo surgical excision, alone or associated with additional treatments, often show a long survival. We report this case to underline the importance and difficulties concerning the preoperative diagnosis of a hemorrhagic intramedullary lesion.

High prognostic potential of glioblastoma stem cell analysis

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Background: Cancer stem cells (CSCs) are a rare cell population responsible for tumor development and maintenance. Recent studies have shown that glioblastoma stem cells express the CD133 marker and are resistant to radiotherapy and chemotherapy. However, clinical data based on the study of CSCs in patients with glioblastoma are not available yet. Methods: Glioblastoma samples from 44 patients treated with complete or partial tumorectomy, followed by radiotherapy and temozolomide were prospectively analyzed. Immunohistochemistry was performed to evaluate the prognostic value of the number of CD133+ cells present in tumors. Moreover, the relationship between the ability to generate long-term culture of tumorigenic cells in vitro and the clinical outcome of glioblastoma patients was tested. Results: CD133 expression did not show an overall prognostic value. CSC cultures were obtained from 14 of the 44 tumors (32%). The generation of CSCs emerged as significant independent prognostic factor by the Cox multivariate analyses, with an adjusted hazard ratio of 2.50 (95% CI, 1.04 to 6.06; P=0.004). The median overall survival among patients with tumors generating CSCs was 8.0 months (95% CI, 4.0 to 11.5), as compared with 15 months (95% CI, 11.0 to 19.0) among those without generation of CSCs (P=0.0002). The median progression-free survival was 3.5 months (95% CI, 2.0 to 6.0) for glioblastoma generating CSCs and 9.0 months (95% CI, 7.0 to 12.0) for glioblastoma not generating CSCs (P=0.0001). A higher CD133 expression significantly associated with tumors generating CSCs (P=0.006), and correlated with a higher risk of death in patients with tumors generating CSCs in vitro (hazard ratio of 1.65, 95% CI, 1.05 to 2.60; P=0.0285). Conclusions: Generation of long-term culture of tumorigenic CSCs in vitro from glioblastoma predicts a poor clinical outcome for patients, in terms of both overall and progression-free survival. In tumors generating CSCs, CD133 expression may have a prognostic value.

No significant financial relationships to disclose.

Unilateral endolymphatic hydrops: what about the contralateral ear?

INTRODUCTION

The early recognition of incipient Meniere's disease (MD) in the asymptomatic ear of a patient with known unilateral disease has profound implications for patient management and follow-up, but the criteria for a right and precocious diagnosis is still controversial.

MATERIALS AND METHODS

We evaluated forty-nine patients with MD, selected according to Committee on Hearing and Equilibrium guidelines. All patients underwent laminar tonal audiometry, stapedial reflex study, Glycerol dehydration test, Auditory Brainstem Response (ABR) vestibular examination. MRI was performed in 14 patients.

RESULTS

A raised hearing threshold in the contralateral ear was found in 27 patients, but only 7 (14.3%) fulfilled the requirements to be considered affected by bilateral MD. The average delay of occurrence in the contralateral ear was 7 years (from 5 to 12 years). The glycerol test was positive only in 4 patients with unilateral MD and moderate hearing loss. It was not positive in any case of bilateral MD. The membranous endolymphatic duct and sac is not well visualised with MRI on the affected side in the majority of patients.

CONCLUSION

A MRI study must be included in the diagnostic protocol for MD and with improvements in this imaging modality will possibly allow detection of variations in the size of inner ear structures. Glycerol dehydration test was useful only in selected cases. A full assessment of incipient disease in the asymptomatic ear in unilateral Meniere's disease should be undertaken. A conservative approach in surgical treatment of unilateral MD is recommended because of the possibility of evolution of a bilateral form, which can occur even 10 years after the onset of the disease.

Telomerase in brain tumors

INTRODUCTION

In recent years, many scientists involved in cancer research have directed their attention to telomerase, an enzymatic complex which is specifically involved in duplicating telomeres, the very ends of linear chromosomes. The discovery that most immortal cell lines in vitro and human tumor cells in vivo have telomerase activity, in contrast to telomerase-negative normal somatic cells, has made telomerase a candidate for use as a molecular marker of malignancy and even as a target for anticancer therapies. Thus, the assessment of the role of telomerase activity in neoplastic transformation has become a key issue in oncology, as stated by the exponential increase of papers on telomerase in the last 5 years.

OBJECT

In this paper, we review some recent data from the literature, including our own studies, on the regulation of telomerase activity in brain tumors.

Evidence for telomerase involvement in the angiogenesis of astrocytic tumors: expression of human telomerase reverse transcriptase messenger RNA by vascular endothelial cells

OBJECT

Evidence from recent in vitro studies indicates that reactivation of telomerase, the enzyme that synthesizes the telomere ends of chromosomes, is a crucial event in the unlimited clonal expansion of endothelial cells that precedes the neoplastic conversion of these cells. It is known that high-grade gliomas express telomerase and that, in these neoplasms, proliferating endothelial cells may undergo transformational changes with development of sarcomatous components within the primitive tumor. To assess whether telomerase is involved in the endothelial cell proliferation that characterizes brain tumor angiogenesis, the authors investigated at the single-cell level the expression of messenger (m)RNA for the human telomerase catalytic subunit human telomerase reverse transcriptase (hTERT) by vascular cells of astrocytic tumors.

METHODS

The in situ hybridization (ISH) method was performed by processing histological sections with specific riboprobes for hTERT and for c-myc, an oncogene that is known to upregulate hTERT. Results of the ISH studies were compared with proliferative activity, as estimated by Ki-67 immunostaining. The expression of hTERT mRNA by vascular endothelial cells was related to the histological grade of the tumor because it was detected in five (29%) of 17 low-grade astrocytomas, nine (56%) of 16 anaplastic astrocytomas, and 19 (100%) of 19 glioblastomas multiforme (GBMs). Expression of c-myc mRNA was strictly correlated with that of hTERT mRNA. In low-grade astrocytomas and anaplastic astrocytomas, a dissociation was noted between hTERT mRNA expression and the proliferation rate of endothelial cells. Conversely, GBMs displayed a significant correlation between the level of hTERT mRNA expression and endothelial cell proliferation. Data from an in vitro assay in which human umbilical vein endothelial cells were stimulated to proliferate by adding vascular endothelial growth factor and an ISH study of newly formed vessels surrounding brain infarcts confirmed that expression of hTERT mRNA does not merely reflect the proliferative status of endothelial cells but represents a specific feature of brain tumor neovascularization.

CONCLUSIONS

The results of this study are consistent with a role of telomerase in the angiogenesis of astrocytic tumors. Expression of hTERT mRNA by tumor vascular cells is an early event during the progression of astrocytic tumors, which precedes endothelial cell proliferation and may represent a first sign of dedifferentiation. Other than elucidating the mechanisms of tumor angiogenesis, these results encourage research on antitelomerase drugs for the treatment of malignant gliomas.

Acrylic hydrogel implants after spinal cord lesion in the adult rat

Acrylic hydrogels, like the polymer of 2-hydroxyethyl methacrylate, are biocompatible, mechanically stable, porous materials that can be coated with collagen or laminin acting as bioadhesive substrates. Poly-2-hydroxyethyl methacrylate sponges have been proposed for restoring the anatomical continuity of damaged neural structures. In the present work, the ability of poly-2-hydroxyethyl methacrylate sponges to provide the injured spinal cord neurons with a conductive substrate for their regenerating axons was investigated in 32 adult Wistar rats. Collagen impregnated poly-2-hydroxyethyl methacrylate sponges were implanted into suction cavities of the dorsal funiculus of the spinal cord. Two to four months after implantation, the spinal cord was removed and processed for histology, and S100 and GFAP immunohistochemistry. To study axonal regeneration into the sponge, the spinal cord or the sensorimotor cortex were injected with 0.05-0.1 microl of an 8% solution of lectin-conjugated horseradish peroxidase or 10% dextran tetramethylrhodamine. The fibroglial reaction, accumulation of mononuclear cells, and angiogenesis at the interface between the spinal cord and the sponge were minimal. Cystic cavitation in the spinal cord was virtually absent. Anterograde labeled axons were seen to penetrate and to elongate the full length of the sponge. These results demonstrate that poly-2-hydroxyethyl methacrylate sponges represent a safe supportive material for regenerating spinal cord axons.

Gadolinium in human glioblastoma cells for gadolinium neutron capture therapy

157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the microdistribution of Gd in cultured human glioblastoma cells exposed to Gd-diethylenetriaminepentaacetic acid (Gd-DTPA). We demonstrated, with three independent techniques, that Gd-DTPA penetrates the plasma membrane, and we observed no deleterious effect on cell survival. A systematic microchemical analysis revealed a higher Gd accumulation in cell nuclei compared with cytoplasm. This is significant for prospective GdNCT because the proximity of Gd to DNA increases the cell-killing potential of the short-range, high-energy electrons emitted during the neutron capture reaction. We also exposed Gd-containing cells to thermal neutrons and demonstrated the GdNC reaction effectiveness in inducing cell death. These results in vitro stimulated in vivo Gd-DTPA uptake studies, currently underway, in human glioblastoma patients.

Radial nerve palsy caused by spontaneously occurring nerve torsion. Case report

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.

In situ detection of telomerase catalytic subunit mRNA in glioblastoma multiforme

Activation of telomerase may allow unlimited cell proliferation and immortalization. One of the telomerase protein subunits has a reverse transcriptase (hTERT) activity that is essential for telomerase function and regulation. In human gliomas, telomerase is frequently associated with malignant tumor progression. In our study, we investigated the expression of hTERT at the cellular level in 34 primary de novo glioblastoma multiforme (GBM) by in situ hybridization (ISH). The expression of hTERT in tumor tissue was also assessed by RT-PCR. In addition, telomerase activity measured by telomeric repeat amplification protocol (TRAP) and telomere length polymorphism assayed by telomere restriction fragment (TRF) Southern blot were investigated. We found that all GBM, including those with negative TRAP reaction, contained abundant amounts of cytoplasmic hTERT mRNA. Interestingly, the ISH analysis revealed that the hTERT mRNA was homogeneously expressed by the whole tumor cell population in about 60% of the GBM. In the remaining cases, hTERT was absent in subsets of tumor cells. TRF analysis, which shows that both TRAP-positive and TRAP-negative de novo GBM have elongated telomeres, further supports that telomerase activity is present in all de novo GBM. Correlations with tumor size and extent of necrosis suggest that hTERT reactivation is an early event in GBM development and that telomerase activity may be lost in subpopulations of neoplastic cells during tumor progression. Finally, ISH analysis of hTERT mRNA seems to provide a prognostic parameter for primary de novo GBM.

Microsatellite instability in primary brain tumors

Microsatellite instability has been reported in hereditary colorectal cancer syndrome and in various kinds of human sporadic tumors. It has also been shown in brain tumors, although with conflicting results. In the present study, DNA samples obtained from 20 primary brain tumors (10 glioblastomas, three astrocytomas, five meningiomas, one ependymoma, one hemangiopericytoma) were analyzed to detect microsatellite instability. Nine microsatellites, mono, di-, tri- and tetranucleotide repeat markers, located on nine different chromosomes, were used. Four of the 20 neoplasias (20%) showed microsatellite alterations in tumor DNA with respect to normal DNA. Two glioblastomas and one atypical meningioma (15%) showed additional bands or bands with shift of electrophoretic mobility, whereas allelic loss was observed in two glioblastomas (10%). In one glioblastoma, one allelic loss and one extra allele were observed at two different loci. These data indicate that in primary brain tumors there is not a high genetic instability. Although we used markers with inherently high levels of instability, only sporadic microsatellite alterations were found. Consequently, alterations in the mechanisms of DNA mismatch-repair, the most important cause of replication errors in hereditary and sporadic colorectal cancers, do not seem to play a major role in the oncogenesis of primary brain tumors.

Phenotypic change of human cultured meningioma cells

One objection to using cell cultures for studying the proliferation of tumors is the potential for phenotypic changes that may occur in vitro. Here, we compared the antigen pattern expression of cultured meningioma cells with that of the primary tumor. Cell cultures established from 9 intracranial meningiomas and deparaffinized sections of the resected tumors were analyzed for immunophenotyping with the following antibodies: vimentin, cytokeratin, epithelial membrane antigen, S-100, neuron-specific enolase, synaptophisin, factor VIII-related antigen, CD4, CD31, CD34, CD45RB, CD68-PGM1, CD68-KP, and myeloid/histiocyte antigen (MAC387). Overall, the cultured meningioma cells retained the main feature of the primary tumor, being positive both for mesenchymal antigens and for epithelial antigens. Interestingly, the cultured meningioma cells abundantly expressed the CD68 antigens at early passage. The CD68 antigens, which are normally found on hematopoietic cells like macrophages and monocytes, were not detectable on meningioma cells in situ. Our results show that phenotypic changes on human meningioma cells may occur in vitro. This phenomenon suggests caution when transposing the in vitro results to the in vivo condition.

Menierè's disease: is it a bilateral disease?

BACKGROUND

Bilateral Meniere's disease (MD) is still controversial due to different criteria used to assess the involvement of the primarily affected ear and the contralateral one. We evaluated the percentage of bilateral forms in 49 patients with MD.

METHODS

49 patients with (MD) were studied. All were selected according to the following requirements: history, tonal audiometry, glycerol test, Auditory Brainstem Response (ABR), vestibular examination. Magnetic Resonance (MR) was performed in 14 patients.

RESULTS

A raised hearing threshold in the contralateral ear was found in 23 patients, but only 7 (14.3%) fulfilled the requirements to be considered affected by bilateral MD. The delay of occurrence in the contralateral ear was 7 years (from 5 to 12 years). Submillimeter Magnetic Resonance is determinant for differential diagnosis with Meniere-like syndromes.

CONCLUSIONS

A conservative approach in surgical treatment of unilateral Meniere's disease is recommended because of the possibility of evolution in a bilateral form, that can occur even after 10 years from the onset of the disease.

Telomerase expression in intracranial tumours: prognostic potential for malignant gliomas and meningiomas

AIM

To evaluate the diagnostic value of telomerase expression in intracranial tumours.

METHODS

98 surgical specimens from different neoplasms were analysed by the telomeric repeat amplification protocol (TRAP) and the presence of telomerase compared with the histological diagnosis and the proliferation index.

RESULTS

A high degree of positivity for telomerase activity was found in glioblastomas and atypical/anaplastic meningiomas. Telomerase activity was poorly detected in anaplastic astrocytomas.

CONCLUSIONS

The TRAP assay seems to be a valuable index for identifying meningeal tumours with aggressive behaviour.

Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors. Case report

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 10(2). 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.

Motonuclear changes after cranial nerve injury and regeneration

Little is known about the mechanisms at play in nerve regeneration after nerve injury. Personal studies are reported regarding motonuclear changes after regeneration of injured cranial nerves, in particular of the facial and oculomotor nerves, as well as the influence that the natural molecule acetyl-L-carnitine (ALC) has on post-axotomy cranial nerve motoneuron degeneration after facial and vagus nerve lesions. Adult and newborn animal models were used. Massive motoneuron response after nerve section and reconstruction was observed in the motonuclei of all nerves studied. ALC showed to have significant neuroprotective effects on the degeneration of axotomized motoneurons. Complex quantitative, morphological and somatotopic nuclear changes occurred that sustain new hypotheses regarding the capacities of motoneurons to regenerate and the possibilities of new neuron proliferation. The particularities of such observations are described and discussed.

Surgical treatment of clival chordomas: the transsphenoidal approach revisited

This is a report of 12 cases of clival chordomas that were surgically treated at the Catholic University Medical School, Rome, Italy, over a 7-year period. The study emphasizes the role of the transsphenoidal approach. The study group included seven men and five women whose ages ranged from 26 to 80 years (mean 49.8 years). Diplopia was the most common presenting symptom (eight cases). The tumor involved the upper and middle clivus in five cases, the middle clivus in five, and the lower clivus in two cases. One patient developed spinal metastasis. On histological examination, eight cases proved to be typical chordomas, three cases had a chondroid component, and one case of chordoma had atypical features. Immunohistological staining for vimentin and epithelial membrane antigen was positive in all cases. Follow-up periods ranged from 14 to 86 months (mean 40.2 months). The primary treatment consisted of surgery. Ten patients with chordomas of the upper and middle clivus underwent a total of 13 transsphenoidal procedures. Total tumor removal was achieved in seven cases, subtotal removal in two, and partial removal in one case. In the two cases of lower clival chordomas, total removal was accomplished in one and partial removal in the other. After total removal, no recurrence was noted at 14 to 86 months (mean 37.5 months). In the cases undergoing operation via a transsphenoidal approach, there was zero morbidity and one cerebrospinal fluid fistula that resolved without surgery. The tumor recurred in two patients after subtotal and partial removal, respectively. The authors opted to reoperate in cases of recurrence. Postoperative radiotherapy was administered in only two cases in which further surgery was not indicated because of medical reasons or because such a procedure was contrary to the patient's wishes. When mortality and morbidity rates of this group are compared to those of chordoma patients who were treated with extensive skull-base surgery, the results prompt a reappraisal of the transsphenoidal approach in the treatment of clival chordomas.

Hydrocephalus and macrocrania: surgical or non-surgical treatment of postshunting subdural hematoma?

BACKGROUND

Subdural hematoma is a well-known complication of hydrocephalus shunting procedures. Since the advent of modern neuroimaging techniques, a more realistic incidence of subdural hematomas in shunted patients has been recognized. The description of several asymptomatic cases raises the problem of choosing the most appropriate therapeutic policy for such a condition.

METHODS

We report two cases with long standing hydrocephalus and macrocrania in which bilateral huge acute and subacute postshunting subdural hematoma developed and remained asymptomatic.

RESULTS

The first patient was treated initially by surgery. Subsequently, despite the persistence of the subdural collections, a nonsurgical policy was chosen. The second patient was deliberately nonsurgically treated.

CONCLUSIONS

On the basis of our experience, we conclude that a nonsurgical policy should be followed in patients with long standing hydrocephalus and macrocrania, if they develop postshunting large hemorrhagic subdural collections and remain asymptomatic.

Superior cervical ganglion regenerating axons through peripheral nerve grafts and reversal of behavioral deficits in hemiparkinsonian rats

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 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 micrometer 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.

Effects of levo-acetylcarnitine on second motoneuron survival after axotomy

Little is known about factors that regulate the survival of cranial motoneurons which project to peripheral targets. Various neurotrophic factors of central and peripheral origin have been isolated. In this study, we examined thirteen newborn Wistar rats to determine the effects of acetyl-L-carnitine treatment on the survival of motoneurons within the facial nucleus after transection of the facial nerve. Acetyl-L-carnitine was administered for 7 days in seven rats after nerve transection, while saline solution was injected in 6 rats used as controls. Both the motoneuron number and the motoneuron diameter were significantly higher in the facial nucleus of the rats treated with acetyl-L-carnitine than in the facial nucleus of the control rats. The results obtained suggest that acetyl-L-carnitine can rescue a substantial number of facial motoneurons from axotomy-induced cell death. Compared to neurotrophic factors, because of its simple molecular structure, acetyl-L-carnitine permits a safe oral and parenteral administration. It is suggested that acetyl-L-carnitine could be considered for use as a therapeutic agent in neurodegenerative disorders.