ß-Hydroxybutyrate Detection with Proton MR Spectroscopy in Children with Drug-Resistant Epilepsy on the Ketogenic Diet.

BACKGROUND AND PURPOSE: The ketogenic diet, including both classic and modified forms, is an alternative to antiepileptic medications used in the treatment of drug-resistant epilepsy. We sought to evaluate the utility of proton MR spectroscopy for the detection of ß-hydroxybutyrate in a cohort of children with epilepsy treated with the ketogenic diet and to correlate brain parenchymal metabolite ratios obtained from spectroscopy with ß-hydroxybutyrate serum concentrations. MATERIALS AND METHODS: Twenty-three spectroscopic datasets acquired at a TE of 288 ms in children on the ketogenic diet were analyzed with LCModel using a modified basis set that included a simulated ß-hydroxybutyrate resonance. Brain parenchymal metabolite ratios were calculated. Metabolite ratios were compared with serum ß-hydroxybutyrate concentrations, and partial correlation coefficients were calculated using patient age as a covariate. RESULTS: ß-hydroxybutyrate blood levels were highly correlated to brain ß-hydroxybutyrate levels, referenced as either choline, creatine, or N-acetylaspartate. They were inversely but more weakly associated with N-acetylaspartate, regardless of the ratio denominator. No strong concordance with lactate was demonstrated. CONCLUSIONS: Clinical MR spectroscopy in pediatric patients on the ketogenic diet demonstrated measurable ß-hydroxybutyrate, with a strong correlation to ß-hydroxybutyrate blood levels. These findings may serve as an effective tool for noninvasive monitoring of ketosis in this population. An inverse correlation between serum ß-hydroxybutyrate levels and brain tissue N-acetylaspartate suggests that altered amino acid handling contributes to the antiepileptogenic effect of the ketogenic diet.

Tract-based spatial statistical analysis of diffusion tensor imaging in pediatric patients with mitochondrial disease: widespread reduction in fractional anisotropy of white matter tracts.

BACKGROUND AND PURPOSE: Often diagnosed at birth or in early childhood, mitochondrial disease presents with a variety of clinical symptoms, particularly in organs and tissues that require high energetic demand such as brain, heart, liver, and skeletal muscles. In a group of pediatric patients identified as having complex I or I/III deficits on muscle biopsy but with white matter tissue appearing qualitatively normal for age, we hypothesized that quantitative DTI analyses might unmask disturbance in microstructural integrity. MATERIALS AND METHODS: In a retrospective study, DTI and structural MR brain imaging data from 10 pediatric patients with confirmed mitochondrial disease and 10 clinical control subjects were matched for age, sex, scanning parameters, and date of examination. Paired TBSS was performed to evaluate differences in FA, MD, and the separate diffusion direction terms (λr and λa). RESULTS: In patients with mitochondrial disease, significant widespread reductions in FA values were shown in white matter tracts. Mean diffusivity values were significantly increased in patients, having a sparser distribution of affected regions compared with FA. Separate diffusion maps showed significant increase in λr and no significant changes in λa. CONCLUSIONS: Despite qualitatively normal-appearing white matter tissues, patients with complex I or I/III deficiency have widespread microstructural changes measurable with quantitative DTI.

When might hemispheric favouring of epileptiform discharges begin?

PURPOSE: EEG studies based on adult populations report interictal epileptiform discharges (EDS) favour the left hemisphere. It is not clear when favouring becomes apparent as similar paediatric studies have not been performed. METHODS: The authors reviewed 1,579 paediatric EEG interpretations for evidence of hemispheric favouring of focal epileptiform discharges. Analysis focused on first-time EEG results. RESULTS: Right hemispheric favouring of interictal epileptiform discharges occurs in childhood, it remits around 5 years of age whereupon left-sided favouring occurs more frequently (P=0.004, Fisher's Exact). CONCLUSION: Hemispheric vulnerabilities to interictal focal epileptiform activity may display discrete age-related favouring. These findings are discussed in context of normal hemispheric maturation.

Hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a complex combination of cardiac malformations that probably results from multiple developmental errors in the early stages of cardiogenesis and that, if left untreated, invariably proves fatal. A variety of chest radiographic findings are seen in patients with HLHS, including an enlarged cardiac silhouette (notably a prominent right atrium), pulmonary venous hypertension, an atrial septal defect, and valvular stenosis or atresia. The recent evolution of palliative surgical procedures (modified Norwood procedure, bidirectional cavopulmonary shunt, modified Fontan procedure, aortic valvuloplasty, heart transplantation) has increased the survival rate in children with HLHS. Echocardiography allows accurate assessment of the size and location of the ductus arteriosus, the hemodynamics of the aortic root, the patency and size of the foramen ovale or atrial septal defect, and the presence of a ventricular septal defect to help determine whether surgical intervention is appropriate and, if so, to facilitate planning. Pediatric radiologists now view radiologic images obtained in patients with HLHS before surgical intervention and at important intervals during treatment. Familiarity with the malformations that characterize HLHS and the surgical procedures used to enhance postnatal survival will help pediatric radiologists provide better care for patients with this relatively common pathologic condition.

Epilepsy surgery in infancy.

Surgery for intractable epilepsy is being offered at progressively younger ages, including infancy. The most common causes of catastrophic epilepsy in very young surgical candidates are focal malformations of cortical development and low-grade tumors. Additional causes include Sturge-Weber syndrome, epidermal nevus syndrome, hemimegalencephaly, and prenatal or perinatal infarction. Many infants manifest with focal seizures, whereas some patients have infantile spasms in the setting of a focal epileptogenic lesion. Video electroencepholography, magnetic resonance imaging, and positron emission tomography are critical investigations to explore surgical options. In small series, the percentage of infants free of seizures after surgery was in the range of 60%. This is similar to that seen after epilepsy surgery in older children, adolescents, and adults. However, larger series with long-term follow up will be important. Furthermore, the extensive procedures required in infants for removal of the epileptogenic developmental lesions entail some risk, and should not be offered in the absence of severe epilepsy. Most infant candidates for epilepsy surgery have significant developmental delay. Few data are available, but anecdotal experience suggests that surgical relief of catastrophic epilepsy may result in resumption of developmental progression. For each infant, the timing of surgery must be carefully considered based on full assessment of the relative risks and benefits, derived from a detailed presurgical evaluation.

Traumatic intracerebral venous thrombosis associated with an abnormal golf swing.

OBJECTIVES: To describe the occurrence of cerebral venous thrombosis in a 40-year-old man whose cerebral event was induced by a poor golf swing, to review the literature on possible mechanisms producing venous thrombosis, and to compare this case with the literature. BACKGROUND: Headache is the most frequent symptom in patients with cerebral venous thrombosis. However, patients presenting with a headache due to cerebral venous thrombosis are uncommon. The known risk factors for thrombosis include both acquired and genetic factors. When the interaction of these two groups occurs, the magnitude of this interaction is thought to produce a dynamic state that can favor thrombosis. Our case report illustrates that moderate levels of anticardiolipin antibodies together with the mild trauma of a golf swing can induce a cerebral venous thrombosis. This case also suggests that although headache is rarely due to cerebral venous thrombosis, it should be excluded by good medical acumen and testing. RESULTS: Minor trauma induced by a poor golf swing was chronologically related to the development of a progressive cerebral venous thrombosis. The patient had none of the risk factors associated with a predisposition to venous thrombosis: hypercoagulable state, concurrent infection, pregnancy/puerperium, collagen vascular disorder, malignancy, migraine, false-positive VDRL, previous deep vein thrombosis, renal disease, factor V Leiden, or a hematological disorder. There was no anatomical abnormality that would predispose the patient to a cerebral venous thrombosis. The only laboratory abnormality was a moderate anticardiolipin antibody level (25 GPL). The patient was placed on warfarin sodium therapy and is currently without clinical sequela from the venous thrombotic event. CONCLUSIONS: Under certain circumstances, minor trauma can induce cerebral venous thrombosis. A review of the literature indicates that cerebral venous thrombosis in the presence of anticardiolipin antibodies and in the absence of systemic lupus erythematosus is a rare event. Previously, only major traumatic events have been reported to be associated with cerebral venous thromboses. The chronological development of cerebral venous thrombosis after a faulty golf swing strongly indicates that given a background of moderate levels of anticardiolipin antibodies, even minor trauma can induce a venous thrombotic event.

Atypical manifestations of two cases of trisomy 9 syndrome: rethinking development delay.

Trisomy 9 syndrome is characterized by "bulbous" nose, microphthalmia, dislocated limbs, and other anomalies of skeletal, cardiac, genitourinary, and central nervous systems. With the exception of one reported case study, all surviving infants have had severe mental impairment. The prospect of severe mental retardation often overwhelms parents who are faced with prenatal diagnosis of trisomy 9. We report on two new cases of mosaic trisomy 9, both of whom are only mildly developmentally delayed. One patient presented with the distinctive facial appearance, large fontanels, and joint abnormalities. The other had none of the typical congenital abnormalities. However, the patient was found to have a congenital heart defect and hypoplastic left heart syndrome, which to our knowledge has not been reported previously in the trisomy 9 syndrome. When these two patients are added to the published patients with this syndrome, there appears to be a range of manifestations, especially with respect to mental status, which has not fully been recognized.

The information highway for the pediatrician: an understanding of the Internet for the clinician.

The author details the information highway available to the computer-literate pediatrician: the Internet, Electronic mail (E-mail), the World Wide Web, and explains how to access the information.

Cytokines in human milk.

Breast feeding improves the health of children. The greatest significance is to host defense, prevention of autoimmunity, and development of the digestive system; however, the underlying mechanisms for these effects are not well understood. Based on recent evidence that cytokines might be important in these processes, we have used ELISA to quantitate the cytokines in human colostrum, transitional, and mature milk from mothers delivering preterm or at term. We also used reverse transcription PCR to test breast milk cells for the production of cytokine mRNA. No significant (< 10 pg/ml) GM-CSF, SCF, LIF, MIP-1 alpha, IL-2, IL-4, IL-11, IL-12, IL-13, IL-15, sIL-2R, or IFN-gamma was detected. And, in contrast to earlier studies using bioassays or RIA, no significant IL-1 beta, TNF-alpha, or IL-6 was present; nor was IL-10, which had been tested using less specific antibodies. We did confirm the presence of high levels of M-CSF, which remained high throughout lactation. Human milk contained latent, but not free, TGF-beta 1, and especially TGF-beta 2, both of which may be activated by gastric acid pH. High levels of IL-1RA were detected, and like activated TGF-beta, may protect against autoimmunity. Chemokines, particularly GRO-alpha and MCP-1, but also RANTES and IL-8, were present and could protect against infection. Maternal cells in breast milk expressed mRNA for MCP-1 (20/20), IL-8 (14/20), TGF-beta 1 (14/16), TGF-beta 2 (4/6), M-CSF (9/12), IL-6 (6/12) and IL-1 beta (7/12), and may be a source of these cytokines. mRNA for IL-2, IL-10, IFN-gamma, TNF-alpha was not detected and only weak expression was found for RANTES (1/18). There was considerable variability between individual women, and women delivering preterm had lower levels of several cytokines in colostrum than women delivering at term. Yet, cytokine levels remained high months to years into lactation, providing immunological benefit to the breastfed infant/child.

Acute neurotoxicity of meperidine in an infant.

We report a 6-week-old boy with meperidine neurotoxicity. What distinguished our patient from those previously reported was his minimal exposure to therapeutic doses of meperidine in the setting of normal renal function, and no history of sickle cell anemia, cancer, hepatitis, or cirrhosis. In addition, our patient had no abnormal changes in the electroencephalogram during the event. After only 2 doses of meperidine, he exhibited acute orofacial dyskinesias consisting of tongue thrusting, lip pursing, and facial grimacing combined with prominent flexion of the arms and stiffening of his legs. However, a normal sucking response remained. His symptoms resolved over the next 36 hours and did not respond to naloxone. We believe that this unique presentation of meperidine-induced neurotoxicity may be due to changes in the basal ganglia resulting from perinatal hypoxemia.

Expression of beta-nerve growth factor in cultured cells derived from the hypothalamus and cerebral cortex.

Although the synthesis of nerve growth factor (NGF) in brain regions innervated by magnocellular cholinergic neurons of the basal forebrain is well documented, the cell type(s) able to produce NGF in the central nervous system (CNS) remain only partially characterized. Moreover, little is known regarding the ability of brain areas not innervated by magnocellular cholinergic neurons to express NGF protein. The hypothalamus, which controls the endocrine system, is one of such regions. Primary culture of mixed populations of cells from the fetal hypothalamus were used to identify the presence of NGF in this brain area. Immunocytochemistry revealed that hypothalamic oligodendrocytes and a subpopulation of neurons expressed the NGF protein. In contrast, astrocytes were either immunonegative or equivocally stained. To define whether synthesis of NGF is restricted to a particular cell type, cultures of purified astrocytes, oligodendrocyte progenitor (oligoP) cells and neurons were utilized. They were obtained from the neonatal cerebral cortex to ensure an adequate yield of glial cells. Virtually the entire population of cerebral oligoP cells were found to express NGF protein. In contrast, and similar to hypothalamic astrocytes, cerebral type I astrocytes isolated at the same time as oligoP cells exhibited little or no NGF staining. When type I astrocytes were induced to differentiate in the presence of a serumless, chemically defined medium, a subpopulation of the culture became more robustly positive for the NGF protein. Contrasting with these differences in NGF immunoreactivity, Northern analysis of RNA isolated from purified cerebral type I astrocytes, oligoP cells and neurons demonstrated that NGF mRNA was expressed in each of these cell types at approximately the same levels. The results indicate that: (a) when placed in culture, each of the major cell types within the CNS has the capability of transcribing the NGF gene, and (b) despite similar NGF mRNA levels the cellular content of NGF protein is greater in a subpopulation of neurons and in oligodendrocytes than in astrocytes, suggesting differences in NGF post-transcriptional regulation between these cell types. In addition, the presence of NGF in hypothalamic cells suggests that NGF may be involved in the regulation of specific hypothalamic neuronal systems.

The regulation of proenkephalin expression in a distinct population of glial cells.

The expression of opioid genes was examined in isolated populations of glial cells in primary culture. Northern blot analysis of purified type I astrocytes, oligodendrocytes and mixed oligodendrocyte-type-2-astrocyte lineage cells derived from cerebral cortex demonstrated robust expression of proenkephalin mRNA exclusively in type I astrocytes. The expression of proenkephalin mRNA was stimulated by the beta-adrenergic agonist isoproterenol, and 8-(4-chlorophenyl thio)adenosine 3'-5'-cyclic monophosphate (cpt-cAMP). Both of these compounds regulated a proenkephalin-chloramphenicol acetyltransferase fusion gene transiently transfected into type I astrocytes. HPLC and immunoassay of the cell culture media revealed significant levels of unprocessed proenkephalin secreted by the cell and this secretion was stimulated by isoproterenol and cpt-cAMP. The relatively high levels of proenkephalin expressed suggest that enhanced expression in astrocytes may be important during neural development, in trauma-induced gliosis and in neuroimmune interactions.

Myelination of axons within cytosine arabinoside treated mouse cerebellar explants by cultured rat oligodendrocytes.

Cell suspensions of cultured purified rat oligodendrocytes prepared by the differential substrate adhesion method were applied to neonatal mouse cerebellar explant cultures in which myelination and oligodendrocyte maturation had been irreversibly inhibited by exposure to cytosine arabinoside. Myelination of Purkinje cell axons within 92% of the host explants was observed 2-5 days after oligodendrocyte application. Ultrastructurally, mature oligodendrocytes and axons surrounded by compact myelin, as well as spherules of compact myelin membranes without axons, were present within the cerebellar explants. It is evident that cultured dissociated purified oligodendrocytes retain the ability to myelinate appropriate axons. Such oligodendrocytes may be hyperreactive with regard to myelin membrane formation, as suggested by the presence of spheres of compact myelin without axons.

Insulin/insulin-like growth factor I and other epigenetic modulators of myelin basic protein expression in isolated oligodendrocyte progenitor cells.

The expression of myelin basic protein by the oligodendrocyte is an integral event in the maturation of central nervous system function. Although much is known concerning the various myelin basic protein species, their temporal expression, and processing of RNA transcripts, little is known about the epigenetic factors responsible for the regulation of myelin basic protein (MBP) expression. In this study, we present evidence that insulin/insulin-like growth factor-I can increase the levels of MBP protein in isolated oligodendrocyte progenitor cells cultured in a serumless, chemically defined medium (ODM). Insulin was found to increase MBP protein in a dose-responsive manner, reaching a maximal level at 72 hr of exposure. Both insulin-like growth factor-I (IGF-I) and insulin were demonstrated to have no effect on MBP RNA levels. These data indicate that insulin/IGF-I increased MBP protein levels at a level distal to transcription The dose response of insulin action suggests that it may have a MBP regulatory function, distinct from IGF-I. When added individually, the other supplements of ODM, transferrin (500 ng/ml), and basic fibroblast growth factor (5 ng/ml) had no effect on MBP expression. However, when all three components were combined, a synergistic effect resulting in increased MBP protein and total RNA levels was found. The phorbol ester 12-O-tetradecanoyl phorbol acetate was found to reduce intracellular MBP RNA levels. The cAMP analogue/dibutyryl cAMP had contrasting effects on MBP RNA levels; no effect occurred in cultures grown in fetal calf serum, but a reduction in RNA levels was found in cultures grown in ODM. These data suggest that only a select range of extrinsic factors may be involved in MBP regulation, and depending on the environmental milieu, epigenetic agents may modulate gene activity differently.

Expression of glial fibrillary acidic protein by differentiated astrocytes is regulated by serum antagonistic factors.

We report here that, in culture, the expression of glial fibrillary acidic protein (GFAP) by astrocytes, as well as their shape (flat-polygonal vs. stellate) can be regulated by 4 serum antagonistic factors. Three of these factors are stimulatory, while the fourth exerts an inhibitory effect upon these astrocytic properties. As suggested by temperature and trypsin treatments, the inhibitory factor is a polypeptide or a protein of 15-35 kDa. The stimulatory factors are smaller: two of them have a mol. wt. between 0.2 and 5 kDa; the third is smaller than 0.2 kDa. Treatments with chloroform/methanol, ammonium sulfate, neuraminidase, and papain, indicate that at least one glycolipid and one glycoprotein are involved. We speculate that, during development, cells from the astrocytic line could be susceptible selectively to one or another of these factors, which would explain their great plasticity.

Serum contains inducers and repressors of oligodendrocyte differentiation.

An important stage in oligodendrocyte development is the expression of galactocerebroside (GC), the major glycolipid in myelin. Although oligodendrocyte cell lineage and differentiation in vitro have been the object of many studies, to date there is sparse information on the regulation of GC expression in oligodendrocytes already committed to be positive for GC. We report here that GC expression in these cells is controlled by three serum factors. Two of these, possibly a lipoprotein and a mucoprotein, increase GC levels, whereas the third, probably a glycoprotein, exerts an inhibitory effect. The developmental increase of GC in postnatal rat brain cerebral cultures and its induction by serum factors are reversible phenomena. The isolation of the GC-regulatory factors would allow experimental manipulation of impaired GC expression by differentiated oligodendrocytes.

Binding constants of soluble NGF-receptors in rat oligodendrocytes and astrocytes in culture.

The neuronotrophic factor NGF binds to peripheral neurons of the dorsal root ganglion and the sympathetic nervous system. NGF binds to a cell surface receptor, NGFR, on these cells and displays Kd's of 10(-9) and 10(-11)M. NGF receptors have also been reported for basal forebrain magnocellular neurons. In addition, NGF specifically binds to NGFR on Schwann cells although the biological significance of this binding is not known. Here we report that NGF binds in a saturable and specific fashion to receptors on cultured isolated populations of rat astrocytes but not to oligodendrocytes. The binding to astrocytes in culture displayed a Kd of 2.7 +/- 1.0 nM with 36,000 receptors per cell.

Interleukin-2 inhibition of oligodendrocyte progenitor cell proliferation depends on expression of the TAC receptor.

Interleukin-2 (IL-2) has been shown to inhibit oligodendrocyte progenitor cell proliferation. Within the immune system, IL-2 biological action is dependent strictly on the expression of the IL-2 receptor. The antibody TAC, which specifically binds the lymphocyte IL-2 receptor, has been shown to also bind oligodendrocyte progenitor cells cultured in a serumless, chemically defined medium. The expression of the TAC antigen was found necessary for IL-2 inhibition of oligodendrocyte progenitor cell proliferation. After IL-2 induced down-regulation of the TAC antigen, the progenitor cell was unresponsive to IL-2, even 72 hr after IL-2 withdrawal. During this unresponsive period, the oligodendrocyte progenitor cell was immunocytochemically negative for the TAC antigen. Thus, in contrast to IL-2 receptors on T-cells, IL-2 does not up-regulate its receptor on oligodendrocyte progenitor cells. However, upon interleukin 1 (IL-1) addition both IL-2 responsiveness and TAC immunocytochemical staining reappeared. These data suggest that IL-2 inhibition of progenitor cell proliferation depends on the expression of the TAC antigen, which can be regulated by IL-1.

Interleukin 2 mediates the inhibition of oligodendrocyte progenitor cell proliferation in vitro.

In the immune system, T-lymphocyte proliferation depends on interleukin 2 [IL-2 (T-cell growth factor)] interaction with specific receptors. In this study we show that IL-2 can specifically inhibit the proliferation of neonatal rat oligodendrocyte progenitor cells cultured in a serumless, chemically defined medium (oligodendrocyte-defined medium; ODM). IL-2 inhibited both [3H]thymidine incorporation and increase in cell number. Specificity was shown by precipitating IL-2 activity with anti-IL-2 antiserum. Furthermore, growth inhibition depended on the expression of Tac (an anti-IL-2 receptor monoclonal antibody)-positive receptors (IL-2 receptor). When cells were cultured in the presence of IL-2, both Tac-positive staining and growth inhibition were no longer expressed. The addition of interleukin 1 had no effect on [3H]thymidine incorporation or changes in cell number. However, when IL-1 was subsequently added together with IL-2, Tac expression and IL-2-mediated inhibition of cell proliferation was induced. This inhibitory effect was not due to a sensitive subpopulation because greater than 90% of the culture was Tac positive. Taken together, these data show that IL-2 can specifically inhibit oligodendrocyte proliferation and acts via Tac-positive receptors.