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PubMed2001

Meningiomas of the sellar region presenting with visual impairment: impact of various prognostic factors on surgical outcome in 62 patients.

BACKGROUND: Meningiomas of the supra- and parasellar region can cause insidious visual loss by optic nerve compression. 62 cases with such tumours affecting the anterior optic pathways were analysed to assess the surgical results and prognostic factors with particular attention to visual outcome. METHOD: In all patients, visual deterioration was the first clinical manifestation. Eleven lesions had their origin at the anterior clinoid process, 24 at the tuberculum sellae, 10 at the planum sphenoidale, two in the optic canal, 10 in the medial sphenoidal wing, and five in the olfactory groove. All patients underwent microsurgical tumour resection. Median age at the time of operation was 54 years, median duration of symptoms seven months. The mean follow-up time was 5.2 years (range 2 to 8 years). Statistical analysis of prognostic factors (gender, age, tumour location, tumour size, duration of symptoms, brain tumour interface, resection grade, preoperative visual loss, Glascow Outcome Score) was performed using univariate and multivariate analysis. FINDINGS: The severe morbidity rate was 6.4%. Two patients died within the first 30 postoperative days. Overall, vision improved in 39 (65%) patients, in 11 (18%) it was unchanged, and worse in 10 (17%). Visual prognosis was favourably affected by age under 54 years (p < 0.025), duration of symptoms of less than seven months (p < 0.037), and the presence of an intact arachnoid membrane around the lesion (p < 0.001). Severe preoperative loss of visual acuity (<0.02) appeared to be an unfavourable prognostic factor (p < 0.047). INTERPRETATION: Possible difficulties and surgical outcome in such patients can be predicted successfully. These facts in connection with new therapeutic modalities (radiosurgery, adjuvant therapies) will demand a careful risk assessment and should influence the treatment strategies and the degree of operative aggressiveness in the future.

Adult↗
PubMed2003

Expression of protein zero is increased in lesioned axon pathways in the central nervous system of adult zebrafish.

The immunoglobulin superfamily molecule protein zero (P0) is important for myelin formation and may also play a role in adult axon regeneration, since it promotes neurite outgrowth in vitro. Moreover, it is expressed in the regenerating central nervous system (CNS) of fish, but not in the nonregenerating CNS of mammals. We identified a P0 homolog in zebrafish. Cell type-specific expression of P0 begins in the ventromedial hindbrain and the optic chiasm at 3-5 days of development. Later (at 4 weeks) expression has spread throughout the optic system and spinal cord. This is consistent with a role for P0 in CNS myelination during development. In the adult CNS, glial cells constitutively express P0 mRNA. After an optic nerve crush, expression is increased within 2 days in the entire optic pathway. Expression peaks at 1 to 2 months and remains elevated for at least 6 months postlesion. After enucleation, P0 mRNA expression is also upregulated but fails to reach the high levels observed in crush-lesioned animals at 4 weeks postlesion. Spinal cord transection leads to increased expression of P0 mRNA in the spinal cord caudal to the lesion site. The glial upregulation of P0 mRNA expression after a lesion of the adult zebrafish CNS suggests roles for P0 in promoting axon regeneration and remyelination after injury.

Age Factors↗
PubMedDate not supplied

Optic pathway/hypothalamic gliomas: a dilemma in management.

Optic pathway gliomas follow an unpredictable course. Some remain static for years; others increase rapidly in size and often lead to death. This unpredictability, along with the histological similarity of these tumors, has resulted in controversy about their management. We have reviewed the results of management of all 62 patients with a diagnosis of optic pathway/hypothalamic glioma treated at The Hospital for Sick Children during the years 1976-1990. Twelve patients received no direct treatment, and 3 only a biopsy. Six patients were treated with radiotherapy alone. Eight patients received radiotherapy following a biopsy. Seventeen patients were treated by resection alone and 16 had a resection followed by radiotherapy. Eight patients received chemotherapy in addition to other therapy, and in 5 of them the chemotherapy was given as an initial therapy. Forty-eight patients are well with their visual deficits but 7 of them are receiving hormone replacement therapy. Six patients have significant neurologic deficits and 8 have died.

Brain Neoplasms↗
PubMed1993

Distribution of melatonin receptors in the brain of the frog Rana pipiens as revealed by in vitro autoradiography.

Melatonin binding sites were identified in the brain of the frog Rana pipiens using in vitro autoradiography. Coronal sections were incubated for 1 h in 100 pM 2-125I-iodomelatonin. Specific binding was displaced with 1 microM nonradioactive melatonin. Autoradiographic labeling of 3H-Hyperfilm was observed in areas that receive primary, secondary, and tertiary visual input: the superficial layers of the optic tectum, anterior and posterior thalamic nuclei, striatum, medial pallium, and interpeduncular nucleus. Other areas that demonstrated binding included the medial and lateral septal nuclei, medial preoptic area, suprachiasmatic region, and anterodorsal tegmental nucleus. Binding was also apparent in the distribution of the lateral olfactory tract (lateral pallium), and in tracts associated with visual pathways: optic nerve, chiasm and tract, and lateral and medial forebrain bundles. A high degree of melatonin binding was observed in the left habenular nucleus, but not in the habenulum of the right side of the brain. Radioreceptor binding assays of frog whole-brain homogenate demonstrated specific saturable melatonin binding (Kd = 70 pM, Bmax = 0.80 fmol/mg protein). Melatonin and 6-chloromelatonin were potent displacers of 2-125I-iodomelatonin, while 5-hydroxytryptamine, 5-methoxytryptamine, and N-acetylserotonin were much less potent. Melatonin inhibited the forskolin-stimulated increase in cAMP synthesis in optic tectum explants. These results suggest that high-affinity melatonin receptor binding sites are widely distributed in the telencephalon, diencephalon, and mesencephalon and are very prominent in areas of the frog brain that are associated with visual processing.

Animals↗
PubMedDate not supplied

Bilateral optic nerve hypoplasia associated with cerebral atrophy.

We present a series of 12 consecutive cases of optic nerve hypoplasia. Eight of these were unassociated with significant CNS malformations; of these, two had tomographic evidence of cerebral atrophy. This represents the first adequately documented cases of isolated cerebral atrophy associated with optic nerve hypoplasia. We discuss the increasing prevalence and marked variability of optic nerve hypoplasia, note the lack of clear distinction between primary failure of differentiation and secondary degeneration of optic pathways, and mention the inadequacy of the classic explanation of primary failure of ganglion cell development as the cause of hypoplastic nerves. The cause of cerebral atrophy are mentioned, and we hypothesize that the wide range of CNS insults resulting in atrophy may be responsible for a correspondingly wide range of abnormalities of the optic nerves. We speculate that cerebral atrophy may result in an inadequate cortical mass for induction of normal optic nerve growth, possibly by decreased retrograde axoplasmic flow and insufficient nerve growth factor. We encourage a complete neurologic evaluation, including CAT scan of the brain, in children with optic nerve hypoplasia.

Adolescent↗
PubMed1982

Malignant optic glioma presenting radiologically as a "cystic" suprasellar mass: case report and review of the literature.

The diagnosis of malignant glioma of the optic nerves and chiasm may be difficult because these rare lesions may mimic other suprasellar lesions. We report a case of glioblastoma multiforme of the optic chiasm in which the appearance of the lesion on computed tomographic (CT) scan was consistent with that of craniopharyngioma or cystic pituitary adenoma. We suggest that malignant optic glioma should be considered in the differential diagnosis of an adult with progressive visual loss of rapid onset, even when ophthalmological examination strongly suggests extrinsic compression of the anterior optic pathways and when the CT scan apparently indicates a cystic mass lesion.

Adult↗
PubMed1977

[Architecture of the visual system of Discoglossus pictus (Oth)].

The retinofugal pathways of an "archaic" Anura Discogossus pictus were examinated with Fink-Heimer method following ablation of the retina and after survival times of 5--105 days at 14 degrees C. A description of the diencephalic and mensencephalic architectonics has been done in order to replace the visual system into the general pattern. The scheme of primary optic pathways and centers is similar in Discoglossus and Rana. However, some retinofugal fibers reach the posterolateral part of the ipsilateral tectum opticum. Beside this study, a Golgi study has shown the link which exists between the degeneration territories (neuropils) and the periventricular cell-masses by the way of the dendritic trees of multipolar, bipolar and pear-shaped neurons. An hypothesis about the notion of visual center is formulated. In the tectum, the distribution of degenerations allows to understand the existence of two visual behaviors: avoidance and prey-catching. The signification of the ipsilateral retinotectal pathway is discussed.

Afferent Pathways↗
PubMed1979

Optic nerve fibre lesions in adult cats: pattern of recovery of spatial vision.

Partial deafferentation in the pre-geniculate optic pathways of the adult cat was produced by micro-injection of diphtheria toxin. In this lesion a certain proportion of fibres was damaged while neighbouring fibres remained unaffected. Behavioural methods were used to study the time course, pattern, and extent of recovery of spatial vision after such lesions. Cats were trained to discriminate square-wave gratings from blank fields. A range of grating sizes (0.13--2.61 cycles/degree) at high contrast were presented each day and when performance was consistently 100%, the lesion was placed. At 24 h post-lesion and serially thereafter grating discrimination was tested. Contrast sensitivity was also measured before and after the lesion. All cats recovered to pre-lesion performance levels. The time course of recovery was characterized by an early rapid phase followed by a longer slower phase. The early recovery was temporally coincident with dispersal of oedema at the site of the lesion, while the later slower recovery probably represented a functional reorganization at the synapse. Optic nerve fibre analyses at one year post-lesion showed reduction in fibre content ranging from 33 to 77% in different cats without shift in the fibre size histograms. The length of recovery time was directly related to the magnitude of fibre loss. The return of spatial frequency perception was hierarchical - first medium (1--4 days), then low (1--2 months) and finally high spatial frequencies (5--8 months). Possible mechanisms are discussed and it is suggested that such a pattern of psychophysical results could be accounted for by date than the X-type.

Animals↗
PubMed1985

Topography of regenerating optic fibers in goldfish traced with local wheat germ injections into retina: evidence for discontinuous microtopography in the retinotectal projection.

A small injection of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected into dorsal or ventral peripheral retina in normal goldfish and in goldfish with prior optic nerve crush. Serial sections of tectum were subsequently taken for horseradish peroxidase (HRP) histochemistry 18 hours after injection and studied with light microscopy and densitometric reconstructions. In normals, a small, sharply delineated patch of product 200-300 microns wide was observed at the appropriate medial or lateral periphery of tectum. This product filled the entire SFGS, the main optic termination layer, and fell off abruptly at its edges. No labelling was detected in the optic pathways. In regenerates at about 20 days after nerve crush, these retinal injections yielded product that was dispersed across 1,000 microns or more of tectum but not in a uniform fashion. The densest product was biased toward the appropriate tectal position while product of intermediate density was mainly distributed along a path from the anterior end of tectum to this region. Product in the inappropriate half of tectum was much lighter and typically fiberlike in appearance. By about 40 days, product had condensed considerably at roughly the correct region of tectum but it was not as sharply delimited as in normals. Dense label occupied a single area about twice that of normals and exhibited flanking regions of light label extending for several hundred micrometers. At 59-148 days, a further condensation was observed but into more than one patch of product. The patches were of variable size and consisted of sharply delimited dense product which filled the entire SFGS at each position. Morphologically, these patches bore a remarkable resemblance to the ocular dominance columns previously seen in this system.

Animals↗
PubMed2005

The optic nerve: radiologic, clinical, and pathologic evaluation.

The radiologic investigation of the optic nerve plays an integral part in the diagnostic evaluation of diverse lesions of the optic pathways including inflammatory diseases, vascular disorders and benign and malignant tumors and these radiologic modalities consist principally of CT and MR imaging and, in vascular lesions, MR angiography and conventional angiography. The selection of radiologic studies and their focus is based on the ophthalmologic examination where the ophthalmologist can often determine the suspected location of lesions in the anterior or posterior visual pathways. Furthermore, inspection of the eye, including adnexal structures and funduscopy, provides additional information in the clinical assessment of these patients. With technical advances in the last few years, CT and MR imaging can detect lesions and determine their location and extent with high sensitivity and specificity. This article discusses the radiologic, clinical, and pathologic evaluation of the optic nerve.

Diagnosis, Differential↗
PubMed1979

Importance of corpus callosum for visual receptive fields of single neurons in cat superior colliculus.

1. Section of the posterior two-thirds of the corpus callosum eliminates almost completely the response of superior colliculus (SC) neurons to stimulation of the contralateral eye in split-chiasm cats. On the contrary, the responsiveness of SC neurons to stimulation of the contralateral eye is not abolished by a transection of the posterior and tectal commissures leaving the corpus callosum intact. The callosal section also reduces the number of SC receptive fields abutting the vertical meridian in the ipsilateral eye of split-chiasm cats. 2. In cats with intact optic pathways, a similar callosal section abolishes the SC representation of the ipsilateral visual field in the ipsilateral eye and also reduces the number of receptive fields adjoining the vertical meridian in the same eye. In the contralateral eye, the SC representation of the ipsilateral visual field is reduced in extension to about one-fifth of that seen in cats with intact commissures. 3. The results suggest that the corpus callosum is the main pathway for cross-midline communication of visual information at not only the cortical, but also the midbrain level. The corpus callosum may subserve this function because it contains uninterrupted crossed corticotectal projections or because it transmits visual information from one hemisphere to contralateral cortical areas projecting ipsilaterally to SC. The latter hypothesis is more likely but, in any case, the findings imply that the lack of interhemispheric transfer of visual learning in cats with a chiasmatic and callosal section may depend on a midline disconnection of both subcortical and cortical visual centers. 4. The corpus callosum is also responsible for the representation of the ipsilateral visual field of the ipsilateral eye in the cat SC. The SC representation of the ipsilateral visual field in the contralateral eye is due, in minimal part, to direct retinotectal connections from temporal retina and, for the largest part, to the corpus callosum. 5. Finally, the corpus callosum contributes to the representation of the contralateral visual field near the vertical meridian of the temporal retina in both split-chiasm and normal cats. This is probably due to the scarcity of direct retinotectal projections from this part of the retina and to their supplementation by corticotectal neurons influenced by the callosal afferents.

Animals↗
PubMed2006

Partial visual recovery from radiation-induced optic neuropathy after hyperbaric oxygen therapy in a patient with Cushing disease.

Here we describe the case of a 41-year-old woman with a history of Cushing disease who had previously undergone unsuccessful neurosurgery, followed by stereotactic radiosurgery. More than 4 years after this treatment, she presented severe visual impairment, which started in the left eye and was documented by neuro-ophthalmic evaluation. Radiological assessment by contrast-enhanced magnetic resonance (MR) imaging initially suggested the diagnosis of glioma of the optic nerve and the patient started corticosteroid treatment (first with prednisone, 80 mg/day, followed by dexamethasone, 8 mg/day). Despite the therapy, vision in the left eye rapidly worsened until light was no longer perceptible; similar symptoms and signs also developed in the right eye, evolving to complete temporal hemianopsia. The clinical evidence was confirmed by the rapid progression of the MR picture, which showed homogeneous enhancement of the chiasm and optic nerves. On the basis of these findings, the original diagnosis of glioma was excluded, and radiation-induced optic neuropathy was diagnosed. As corticosteroids had proved inefficacious, hyperbaric oxygen (HBO) therapy was promptly instituted and vision steadily started to improve. This improvement was documented and confirmed by the progressive recovery of the visual field in the right eye and the changes in the sequential follow-up MR scanning. Optic neuropathy is an infrequent but dramatic complication of radiation therapy. Symptoms develop, on average, 12 months after treatment, and the onset may be acute and characterized by the progressive loss of vision in one or both eyes. HBO has already been used to treat this complication, but its efficacy is still controversial. Here, in addition to describing this particular case, which presented a significantly delayed radiation injury of the optic pathways, we provide a brief literature review and discuss some important points.

Adult↗
PubMed1997

Magnetic resonance imaging in optic neuropathy.

Magnetic resonance imaging has revolutionised the ability to investigate intrinsic disease of the anterior optic pathways. We review the data accumulated from this technique not only in the conditions, such as neoplasia, which have traditionally been the domain of neuroimaging, but also in inflammatory, metabolic and degenerative diseases.

Humans↗
PubMed2000

Conformal radiotherapy for paranasal sinus and nasal cavity tumors: three-dimensional treatment planning and preliminary results in 40 patients.

PURPOSE: To assess the possibility to deliver a high and homogeneous irradiation with respect to maximal tolerated dose to the visual pathways for paranasal sinus and nasal cavity tumors. METHODS AND MATERIALS: Forty patients with advanced stage malignant tumors were treated with postoperative (30) or primary (10 patients) conformal radiotherapy (CRT). Five patients were previously irradiated. Six to 15 individually shaped isocentric noncoplanar field arrangements, using a multileaf collimator were designed. Dose-volume histograms (DVH) for the planning target volumes (PTV) and the optic pathways were analyzed in 31 cases. RESULTS: Median and maximal delivered doses to the PTV were 60 (+/-3) and 66 (+/-4) Gy. Dose distributions for critical organs are detailed. Median follow-up was 19 months (3 to 48). Local, nodal, and metastatic recurrences occurred in 8, 2, and 7 cases, respectively. Major prognostic factor for local recurrences was central nervous system (CNS) involvement. One patient died of meningitis. Two patients developed cataract, and 1 patient ipsilateral blindness due to vascular glaucoma. CONCLUSION: CRT for locally advanced paranasal sinus and nasal cavity tumors enables the delivery of high homogeneous doses to the PTV with respect to critical organs, with a low toxicity and a high local control.

Adult↗
PubMed2005

Results of spot-scanning proton radiation therapy for chordoma and chondrosarcoma of the skull base: the Paul Scherrer Institut experience.

PURPOSE: To assess the clinical results of spot scanning proton beam radiation therapy (PT) in the treatment of skull base chordomas and low-grade chondrosarcomas (CS). METHODS AND MATERIALS: Between October 1998 and October 2003, 29 patients (median age, 39 years) with chordomas (n = 18) and CS (n = 11) were treated at the Paul Scherrer Institut (PSI) with protons using the main 510-MeV cyclotron. Tumor conformal application of proton beams was realized by spot scanning technology. The median chordoma and CS dose was 74 and 68 cobalt Gy equivalent, respectively (cobalt Gy equivalent = proton Gy x 1.1). Median gross tumor volumes (GTV) were 16.4 mL (range, 1.8-48.1 mL) and 15.2 mL (range, 2.3-57.3 mL) for chordoma and CS, respectively. Late toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE, v3.0) grading system. The median follow-up time was 29 months (range, 6-68 months). RESULTS: Actuarial 3-year local control rates were 87.5% and 100% for chordoma and CS, respectively. We observed one surgical pathway and one marginal failure in patients with chordomas. No regional failure or distant metastasis was observed. At 3 years, actuarial PFS and OS for the entire cohort was 90% and 93.8%, respectively. Actuarial 3-year complication-free survival was 82.2%. Radiation-induced pituitary dysfunction was observed in 4 (14%) patients (CTCAE Grade 2). No patient presented with post-PT brainstem or optic pathways necrosis or dysfunction. In univariate analysis, age < or =40 years at the time of PT affected favorably on PFS (p = 0.09). CONCLUSION: Spot-scanning PT offers high tumor control rates of skull base chordoma and CS. These results compare favorably to other combined proton-photon or carbon ion irradiation series. Observed toxicity was acceptable. Younger age (< or =40 years) was a favorable prognostic factor of PFS. These preliminary results are encouraging but should be confirmed during a longer follow-up.

Adult↗
PubMed2002

Up-regulation of cadherin-2 and cadherin-4 in regenerating visual structures of adult zebrafish.

Cadherins are homophilic cell adhesion molecules that control development of a variety of tissues and maintenance of adult structures. In this study, we examined expression of zebrafish cadherin-2 (Cdh2, N-cadherin) and cadherin-4 (Cdh4, R-cadherin) in the visual system of adult zebrafish after eye or optic nerve lesions using immunocytochemistry and immunoblotting. Both Cdh2 and Cdh4 immunoreactivities were specifically up-regulated in regenerating retina and/or the optic pathway. Furthermore, temporal expression patterns of these two cadherins were distinct during the regeneration of the injured tissues. Cadherins have been shown to regulate axonal outgrowth in the developing nervous system, but this is the first report, to our knowledge, of increased cadherin expression associated with axonal regeneration in the vertebrate central nervous system. Our results suggest that both Cdh2 and Cdh4 may be important for regeneration of injured retinal ganglion cell axons.

Animals↗