Coriene E. Catsman-Berrevoets

Two new fluorescent retrograde neuronal tracers which are transported over long distances

Two new fluorescent retrograde neuronal tracers are reported: Nuclear Yellow (Hoechst S 769121), which mainly labels the neuronal nucleus; and Fast Blue (diamidino compound 253/50), which mainly labels the neuronal cytoplasm. Both tracers appear to be transported effectively over long distances in rat and cat.

Double retrograde neuronal labeling through divergent axon collaterals, using two fluorescent tracers with the same excitation wavelength which label different features of the cell.

SummaryRecent studies show that several fluorescent substances are transported retrogradely through axons to their parent cell bodies and label in different colors different features of the cell at the same 360 nm excitation wavelength. Thus, Bisbenzimide (Bb) and “Nuclear Yellow” (NY; Hoechst S 769121) produce green and golden-yellow retrograde labeling of the neuronal nucleus. “True Blue” (TB) and “Fast Blue” (FB) produce blue retrograde labeling of the neuronal cytoplasm. In the present study the possibility of retrograde double labeling of neurons by way of divergent axon collaterals using combinations of Bb or NY with TB or FB has been explored in rat and cat. The findings show that in these animals these tracer combinations are transported retrogradely through two axon collaterals to one and the same cell. Neurons which are retrogradely double-labeled with these tracer combinations display a blue fluorescent cytoplasm and a white or golden-yellow fluorescent nucleus at the same 360 nm excitation wavelength. Therefore, these tracer combinations can be successfully used to demonstrate the existence of divergent axon collaterals in the brain.

Retrograde transport of bisbenzimide and propidium iodide through axons to their parent cell bodies

Two fluorescent substances bisbenzimide (Bb), which fluoresces yellow-green and propidium iodide (PI), which fluoresces orange were found to be transported retrogradely through axons to their parent cell bodies in rat and cat. Bb gives a very strong and long lasting fluorescent retrograde neuronal labeling and is very effectively transported over long distances both in rat and cat. Bb and PI also label glial nuclei around retrogradely labeled neurons. Bb in addition labels glial nuclei along axons through which it is transported. Bb and PI can be transported retrogradely through two divergent collaterals to one and the same cell.

Retrograde neuronal labeling by means of Bisbenzimide and Nuclear Yellow (Hoechst S 769121). Measures to prevent diffusion of the tracers out of retrogradely labeled neurons.

Bisbenzimide and Hoechst S 769121 (Nuclear Yellow, NY), when transported retrogradely through axons to their parent cell bodies, may migrate out of the axons and the cell bodies, as indicated by fluorescence of adjoining glial nuclei. This migration was found to take place both in vivo and in vitro during storage of the sections in water. When using the tracers in 1% concentrations the in vivo migration may be controlled by restricting the survival time. The in vitro migration may be prevented by rapid histological processing of the material.

The syndrome of 'cerebellar' mutism and subsequent dysarthria

“Cerebellar” mutism refers to a specific childhood disorder in which a complete but transient loss of speech, followed by dysarthria, occurs after removal of a cerebellar tumor. We present a consecutive series of 15 children with this disorder, which we prefer to designate “mutism and subsequent dysarthria.” The conditions in which it develops suggest also an extracerebellar component of cerebellar mutism. Hydrocephalus at presentation, localization of tumor adjacent to the fourth ventricle, and postsurgical edema of the pontine tegmentum are involved in its development.

Long-term sequelae in children after cerebellar astrocytoma surgery

Objective: To study long-term effects on neurologic, neuropsychological, and behavioral functioning in children treated for cerebellar pilocytic astrocytoma (CPA) without additional radio- and chemotherapy. Methods: The authors assessed speech, language, nonverbal intelligence, attention, memory, executive skills, and visual (-spatial) functions in a consecutive series of 23 children. Neurologic and neuropsychological follow-up ranged from 1 year to 8 years and 10 months after resection. Results: Long-term sequelae in the investigated domains were found in all children. Apraxia, motor neglect, and dysarthric features, as well as language, sustained attention, visual-spatial, executive, memory, and behavioral problems, were observed in various combinations and to different degrees. No clear pattern of neurocognitive disturbances could be discerned in this group. In addition, significant relationships were revealed between severity of preoperative hydrocephalus and visual-spatial skills. The high percentage of children who needed special education reflects the severity of the impairments. Conclusion: Despite the current opinion of a good quality of life after CPA treatment, careful long-term neurocognitive follow-up is needed in order to inform parents and teachers about the behavioral and cognitive sequelae and to contribute to timely social and educational intervention.

Tumour type and size are high risk factors for the syndrome of "cerebellar" mutism and subsequent dysarthria

OBJECTIVE “Cerebellar mutis” and subsequent dysarthria (MSD) is a documented complication of posterior fossa surgery in children. In this prospective study the following risk factors for MSD were assessed: type, size and site of the tumour; hydrocephalus at presentation and after surgery, cerebellar incision site, postoperative infection, and cerebellar swelling. METHODS In a consecutive series of 42 children with a cerebellar tumour, speech and neuroradiological studies (CT and MRI) were systematically analysed preoperatively and postoperatively. Speech was assessed using the Mayo Clinic lists and the severity of dysarthria using the Michigan rating scale. RESULTS Twelve children (29%) developed MSD postoperatively. The type of tumour, midline localisation, and vermal incision were significant single independent risk factors. In addition, an interdependency of possible risk factors (tumour>5 cm, medulloblastoma) was found. CONCLUSION MSD often occurs after paediatric cerebellar tumour removal and is most likely after removal of a medulloblastoma with a maximum lesion diameter>5 cm.

A search for corticospinal collaterals to thalamus and mesencephalon by means of multiple retrograde fluorescent tracers in cat and rat.

An attempt has been made to determine anatomically whether in rat and cat cortical projections to ventrolateral nucleus of thalamus and to mesencephalon are in part composed of corticospinal collaterals. For this purpose two different fluorescent tracers were injected: one in the spinal cord and the other contralaterally in the lateral thalamus and in the mesencephalon respectively. In these experiments Fast Blue and True Blue were used in combination with Nuclear Yellow. Evans Blue was used in combination with Granular Blue. After injections of the tracers into the thalamus and spinal cord two different populations of single retrogradely labeled cortical neurons were found, while after injections in mesencephalon and spinal cord double-labeled cortical neurons occurred. This has lead to the conclusion that in cat and rat corticospinal neurons do not distribute collaterals to specific thalamic nuclei, but do distribute collaterals to mesencephalon. Moreover, the preferential distribution of the double-labeled corticospinal neurons in cat suggest that the corticospinal neurons distributing collaterals to the mesencephalon in part are concentrated in those cortical areas which subserve the steering of movements of the head, neck and trunk.

Early prognostic indicators of outcome in ischemic childhood stroke

The aim of this study was to identify early prognostic factors in children with ischemic arterial stroke. Presenting symptoms, patterns of infarction on magnetic resonance imaging and computed tomography scans, and etiologic findings were compared with clinical outcome in a consecutive series of 31 children with ischemic arterial stroke. Presentation with an altered level of consciousness, seizures, or both and a completed or cortical completed stroke of the middle cerebral artery were found to be significant risk factors for poor outcome. No significant correlation was found between prognosis of childhood stroke and etiology, age at presentation, or gender.

Anti-MOG antibodies plead against MS diagnosis in an Acquired Demyelinating Syndromes cohort.

Background: Acquired demyelinating syndromes (ADS) in children are a group of distinct first immune-mediated demyelinating events of the central nervous system (CNS). Predictive biomarkers for future diagnosis are lacking. A putative target antigen is myelin oligodendrocyte glycoprotein (MOG). We analyzed the presence of MOG antibodies in a cohort of ADS patients in The Netherlands. Methods: Using a cell-based assay, we analyzed 117 children with ADS from a nationwide cohort, whom were divided into five groups: optic neuritis (ON; n = 20), transverse myelitis (TM; n = 7), other monofocal ADS (n = 22), polyfocal ADS without encephalopathy (n = 44) and polyfocal ADS with encephalopathy (n = 24). Additionally, we tested children with other neurological diseases (OND; n = 13), healthy children (n = 31) and adult polyfocal ADS plus encephalopathy (ADEM) patients (n = 29). Results: We found that 21 of the 117 children with ADS tested anti-MOG seropositive (18%). The group of patients with ADEM had the highest prevalence of anti-MOG seropositivity (42% versus 18% in the non-encephalopathic polyfocal ADS patients). Although 47 ADS children had a final diagnosis of multiple sclerosis (MS), in only one of them were MOG antibodies detected (2%), with only borderline positivity. Only 1 out of the 29 adult ADEM patients tested anti-MOG seropositive. Conclusions: MOG antibodies are strongly skewed towards ADS children that present with an ADEM-like disease onset. The presence of such antibodies pleads against a future diagnosis of MS.