Treatment of intracranial ependymoma by surgery alone.

Objective: This study aimed to determine the safety of deferring radiotherapy in pediatric intracranial ependymoma following a radiographically confirmed gross total resection in patients with localized disease.

Methods: Children over age 3 were recruited prospectively from 1990 to 1997, following a surgical impression and radiologic confirmation of a gross total resection of an intracranial ependymoma.

Results: 10/32 cases of intracranial ependymomas were both eligible and gave consent.

Headache and Chiari I malformation in the pediatric population.

There has been disagreement regarding surgical intervention in treating pediatric patients with Chiari I malformation with headache as sole complaint. Therefore, we retrospectively reviewed our experience over a 6-year period, with patients less than 5 years of age (mean = 34.8 months) with radiographically confirmed Chiari I malformation.

Intraparenchymal clear cell meningioma of the brainstem in a 2-year-old child. Case report and literature review.

We report an unusual case of an intraparenchymal clear cell meningioma of the brainstem, occurring in a 22-month-old girl. She presented with bulbar dysfunction and a right hemiparesis due to an intrinsic tumor of the medulla, which was confirmed by radiologic imaging to be focal and with an exophytic component. At surgery, a partial resection was achieved and no dural attachment was found.

Coagulation of herniated cerebellar tonsils for cerebrospinal fluid pathway restoration.

In the past, many different surgical techniques have been proposed for treatment of the Chiari type I malformation. Despite the different technical considerations, in general, the treatment objectives have shared certain features: to prevent/ameliorate tonsillar crowding and to restore normal circulation of cerebrospinal fluid at the foramen magnum. We report a simple technique of coagulation of the herniated cerebellar tonsils in situ to decompress adjacent neural structures and to achieve the above-mentioned goals.

MR of spinal cord ganglioglioma.

Purpose: Our purpose was to describe the MR imaging features in a series of spinal intramedullary gangliogliomas and to compare these findings with the MR features of intramedullary astrocytomas and ependymomas.

Methods: A retrospective analysis was performed of 76 MR examinations in 27 patients with histologically proved spinal ganglioglioma; these were then compared with imaging findings in a representative sample of histologically proved spinal cord astrocytomas and ependymomas.

Results: Statistically significant observations regarding spinal gangliogliomas included young age of the patients (mean, 12 years), long tumor length, presence of tumoral cyst, presence of bone erosion and scoliosis, absence of edema, presence of mixed signal intensity on T1-weighted images, and presence of patchy enhancement and cord surface enhancement.

Diffuse infiltrating astrocytoma of the cervicomedullary region: clinicopathologic entity.

Recent imaging and neurosurgical techniques have led to an improvement in the surgical management of children with brainstem tumors (BSTs). Many children with tumors previously considered 'inoperable' can now benefit from surgery. Increased experience has brought about new theories concerning the growth pattern, natural history, classification and optimal management of these tumors.

Improved coverage in dynamic contrast-enhanced cardiac MRI using interleaved gradient-echo EPI.

An interleaved gradient-echo echo-planar imaging (IGEPI) sequence was modified for and applied to dynamic contrast-enhanced imaging of the heart. Using IGEPI, images with 3.0 x 3.

Treatment of high-grade spinal cord astrocytoma of childhood with "8-in-1" chemotherapy and radiotherapy: a pilot study of CCG-945. Children's Cancer Group.

Object: The purpose of this study was to devise an improved method of treating high-grade gliomas of the spinal cord in children who have a dismal prognosis following conventional treatment.

Methods: Eighteen children with newly diagnosed high-grade astrocytomas arising in the spinal cord were enrolled in the Children's Cancer Group (CCG) protocol 945. Following surgery, they were all assigned to receive two cycles of "8-drugs-in-1-day" (8-in-1) chemotherapy prior to radiotherapy and eight additional cycles thereafter.

On the mechanism of the effects of potassium restriction on blood pressure and renal sodium retention.

Dietary potassium restriction increases sodium and chloride retention, whereas potassium administration promotes both diuresis and natriuresis. In epidemiologic and clinical studies, potassium intake is inversely related to blood pressure and is lower in blacks than in whites. The present studies examined the mechanism by which potassium restriction fosters sodium conservation and the impact of race on this response.

The role of motor evoked potentials during surgery for intramedullary spinal cord tumors.

Objective: This is a prospective study of the methodology and clinical applications of motor evoked potentials (MEPs) during surgery for intramedullary spinal cord tumors.

Methods: Transcranial electrical stimulation was used to activate corticospinal motoneurons, and the traveling waves of the spinal cord were recorded through catheter-electrodes placed epi- or subdurally. Intraoperative MEP monitoring was performed in 32 consecutive patients (age range, 1-50 yr) undergoing resection of intramedullary spinal cord tumors.

Breath-hold R2* mapping with a multiple gradient-recalled echo sequence: application to the evaluation of intrarenal oxygenation.

Blood oxygenation level dependent (BOLD) MRI is sensitive to changes in regional oxygen supply versus demand and is therefore potentially useful in evaluating susceptibility to ischemic injury. Recently, we have demonstrated the use of BOLD MRI to evaluate intrarenal oxygenation using single shot echo-planar imaging (EPI). Here, we present an alternate implementation of BOLD MRI sequence, using multiple gradient echoes, that does not require any specialized hardware.

Urinary cyclic GMP, endothelin, and prostaglandin E2 in normal pregnancy and preeclampsia.

Cyclic GMP, endothelin and prostaglandin E2 (PGE2) all have systemic vasoactive properties (with cyclic GMP acting as a second messenger of nitric oxide). Intrarenally they act as natriuretics and urinary levels reflect intrarenal production. Cyclic GMP and PGE2 also act as important inhibitors of platelet activation and thrombosis.

Transport mechanisms that mediate the secretion of chloride by the rectal gland of Squalus acanthias.

The rectal gland of Squalus acanthias secretes chloride by a mechanism that has been termed "secondary active transport" because it depends on the activity of Na-K-ATPase. As currently described, chloride enters the cell across the basolateral cell membrane via the 2 chloride: sodium: potassium cotransporter. The energy for this electroneutral uphill movement of chloride and potassium is provided by the gradient for sodium directed into the cell.

Role of guanylyl cyclase receptors for CNP in salt secretion by shark rectal gland.

The role of C-type natriuretic peptide (CNP) and its guanylyl cyclase-linked receptors in mediating salt secretion by the rectal gland of the spiny dogfish shark (Squalus acanthias) was investigated using HS-142-1, a competitive inhibitor of the binding of natriuretic peptides to their guanylyl cyclase receptors. CNP binds to receptors and activates guanylyl cyclase in rectal gland membranes in a way that is inhibited by HS-142-1. Guanylyl cyclase activation in rectal gland membranes is far more sensitive to CNP than to atrial natriuretic peptide, whereas the reverse is true for membranes derived from mammalian (rabbit) renal collecting duct cells.

Intraspinal sarcoidosis: diagnosis and management.

Objective: Isolated intramedullary spinal cord or cauda equina involvement by sarcoidosis is quite rare. We report three patients with intraspinal sarcoidosis and absent systemic manifestations of the disease. The clinical presentation, operative management, electrophysiologic studies, pathology, laboratory investigations, and current therapy are discussed with attention to the previous literature.

Using cardiac phase to order reconstruction (CAPTOR): a method to improve diastolic images.

A method is proposed to reconstruct multiphase images that accurately depicts the entire cardiac cycle. A segmented, gradient-recalled-echo sequence (FASTCARD) was modified to acquire data continuously. Images were reconstructed retrospectively by selecting views from each heartbeat based on cardiac phase rather than the time elapsed from the QRS complex.

Pediatric intramedullary spinal cord tumors: is surgery alone enough?

Pediatric intramedullary spinal cord tumors occur infrequently with limited data on treatment strategies and outcome. Over an 11-year period, 44 patients with such tumors who were primarily managed by radical surgery were retrospectively reviewed. The majority of tumors (42/44, 95%) were in the cervical or thoracic spine and were histologically low grade.

Intra-axial tumors of the cervicomedullary junction: surgical results and long-term outcome.

Until recently, intra-axial brainstem tumors were traditionally regarded as surgically inaccessible lesions with a uniformly poor prognosis. However, increasing data indicate that distinct subgroups of brainstem tumors exist that are amenable to surgical intervention. To address this question, we reviewed our experience in the operative management of 39 consecutive patients, in the magnetic resonance imaging (MRI) era, with intra-axial cervicomedullary tumors, in order to determine those factors associated with long-term outcome.

Endothelin and atrial natriuretic peptide levels following radiocontrast exposure in humans.

Radiocontrast exposure is associated with vasoconstriction of the renal vascular bed and, in certain circumstances, with acute renal failure. This may be influenced by the volume of contrast infused or underlying disease, such as diabetes or renal failure. Changes in circulating vascular regulators, such as endothelin and atrial natriuretic peptide (ANP), may play a role in the development and/or prevention of acute renal failure.

Modulation of c-fos and egr-1 expression in the isolated perfused kidney by agents that alter tubular work.

The isolated perfused rat kidney provides a model of selective hypoxia to the medullary thick ascending limb. To investigate the relationship between immediate early gene expression and the extent of hypoxic damage, we determined expression of the immediate early genes (IEG) c-fos and egr-1 in isolated perfused kidneys during standard perfusion and after various measures shown previously to be protective. mRNA levels of c-fos and egr-1 were markedly increased in kidneys after 90 minutes of standard perfusion with Krebs-Henseleit buffer containing albumin.

Increased salt retention and hypertension from non-steroidal agents in the elderly.

We studied blood pressure and natriuretic responses to acute salt loading, and the effect of non-steroidal anti-inflammatory agents on these responses, in five healthy normotensive women aged 65 to 71 years. Five women aged 25 to 31 years acted as controls. Intravenous saline loading, with and without prior ingestion of ibuprofen, was 15 ml/kg/h for 3 h.

Intraoperative spinal cord monitoring for intramedullary surgery: an essential adjunct.

Intraoperative monitoring of the functional integrity of the spinal cord during removal of intramedullary spinal cord lesions is an aid in intraoperative decision making and a primary tool for the prediction of neurological outcome. Motor evoked potential monitoring has become the neurophysiological monitoring technique of choice for that purpose. In the senior author's experience with over 130 pediatric patients suffering from intramedullary spinal cord tumors, the neurophysiological data of both motor and sensory evoked potentials was utilized in an integrative fashion.