Growth of choroid plexus epithelium vesicles in vitro depends on secretory activity.

Although a number of models have been used to study choroid plexus epithelium (CPe) function, analysis in physiological conditions of this polarised epithelium which produces the majority of the cerebrospinal fluid (CSF) and is one of the key barriers between blood and CSF in the brain remains challenging. As CPe cells form polarised CPe vesicles when cultured in Matrigel, we have assessed their behaviour and potential use for pharmacological studies. Like CPe cells in vivo, CPe vesicles express transthyretin, E2f5, Fox-j1 and p73, and contain tight junctions, as indicated by ZO-1 expression and electron microscopy analysis. Time-lapse microscopy shows that CPe cells plated in Matrigel are highly migratory and rapidly form homotypic cell aggregates, which then reorganise to form vesicles whose size increases linearly overtime. Neither aggregate nor vesicle size is affected by AraC treatment, though this inhibitor significantly reduces proliferation in CPe monolayers. Increase in size of vesicles, which have reached a growth plateau is observed following addition of fluorescently-labelled CPe cells, which become incorporated into the vesicle walls. Significantly, treatment with secretion inhibitors blocks vesicle formation and their expansion. These results show that secretion, rather than cell division, controls vesicle growth, consistent with low levels of proliferation and thinning of the CPe observed both in growing vesicles and during CPe development. Therefore, changes in vesicle size can be used to evaluate the effect of putative molecules involved in the regulation of secretion.

Surveillance imaging strategies following surgery and/or radiotherapy for childhood cerebellar low-grade astrocytoma.

OBJECT: The authors sought to evaluate surveillance strategies for the detection and monitoring of residual and recurrent disease in children with cerebellar low-grade astrocytomas (CLGAs) treated surgically or with radiotherapy. Patients were divided into three groups: (1) those in whom a "complete" resection was achieved; (2) those with residual disease with no immediate adjuvant therapy; and (3) those who received radiotherapy for residual/recurrent disease. METHODS: Magnetic resonance (MR) imaging studies and clinical data obtained in children with CLGA who presented between January 1988 and September 1998 were reviewed. Eighty-four children were followed for a mean period of 73 months (range 2-159 months). One child died. Of the 70 children in whom a complete resection was achieved, nine (13%) developed a recurrence detected by surveillance imaging at 6, 8, 9, 9, 13, 27, 39, 44, and 47 months, respectively. Following an incomplete resection, radiologically detected tumor progression leading to further treatment was detected at 7, 9, 12, 13, and 20 months, respectively, and an additional six tumors regressed or stablized. In 11 of 12 children treated with radiotherapy, stabilization/regression occurred radiologically at a mean of 14.9 months. CONCLUSIONS: The authors recommend surveillance MR imaging in children treated for CLGA at 6 months and 1, 2, 3.5, and 5 years following a complete resection and after radiotherapy performed either initially or following recurrence. For follow up of residual tumor, 6-month interval imaging for at least 3 years, yearly images for another 2 years, and subsequent 2-year imaging is recommended.

Surveillance neuroimaging of intracranial medulloblastoma in children: how effective, how often, and for how long?

OBJECT: The goal of this paper was to review brain and spine images obtained in children with medulloblastomas to determine the risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcomes among patients who remain alive 1 month postsurgery. METHODS: Imaging studies and clinical data obtained in children with medulloblastomas, who presented between January 1987 and August 1998, were retrospectively reviewed. Images were termed surveillance if they were follow-up studies and symptom prompted if they were obtained to investigate new symptoms. One hundred seven patients (mean age 6 years and 3 months, range 2 months-15 years and 6 months) were entered into the study. Fifty-three children experienced tumor recurrence; 41 had one recurrence, nine had two, and three had three recurrences. Surveillance imaging revealed 10 of the first 53 recurrences and 15 of all 68 recurrences. When the first recurrence was identified by the emergence of symptoms (42 patients), the children tended to survive for a shorter time (hazard ratio 3.72, 95% confidence interval 1.42-9.76, p = 0.008) than children in whom the first recurrence was detected before symptoms occurred (10 patients). The median survival time following symptomatic tumor recurrence was 4 months and that after surveillance-detected tumor recurrence was 17 months. The median increased survival time among patients whose recurrence was asymptomatic and identified by imaging studies was 13 months, more than half the mean time between surveillance imaging sessions. Incomplete tumor resection was associated with a significantly reduced time to recurrence (p = 0.048) and to death (p = 0.002). The number of recurrences that were experienced was associated with a reduced time to death (p < 0.001). CONCLUSIONS: Surveillance imaging is associated with an increase in survival in children with medulloblastomas. More frequent surveillance imaging in children with incomplete tumor excision and recurrent disease may further improve the length of survival.

Impact of repeated surgical procedures on the incidence and prevalence of latex allergy: a prospective study of 1263 children.

Assessment with questionnaire, skin tests, and immunoglobulin E measurements showed 6 (0.5%) of 1263 children having elective surgery had latex allergy; 50 (4%) others were latex-sensitized. Any previous operation increased the odds of latex sensitization by 13 times; multiple operations had a less marked effect. All children having surgery may need primary prophylaxis for latex.