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Biomedical subjects

M J Noetzel

Publications and source records attributed to M J Noetzel.

34 records · Page 2Linked to original sources

Myelomeningocele: current concepts of management.

Care of an infant with myelomeningocele may begin with prenatal diagnosis, which allows for optimal perinatal care. In the newborn period, the decision for surgical treatment of myelomeningocele must be made promptly, but only after rational discussion with, and consent by, the affected child's family. Advances in newborn care and in surgical techniques, and an improved ability to both detect and treat hydrocephalus and CSF infections, have resulted in better outcomes for these children. Recent insights into the pathogenesis of myelomeningocele suggest that prevention of most of these congenital malformations may be possible through periconceptual vitamin supplementation.

Humans↗

Adrenoleukodystrophy carrier state presenting as a chronic nonprogressive spinal cord disorder.

Females who are heterozygous for adrenoleukodystrophy (ALD) can be identified biochemically. Since most carriers for this disease are asymptomatic, their diagnosis usually occurs only after neurologically abnormal male relatives have been investigated. We describe a woman with a chronic nonprogressive spinal cord syndrome secondary to the ALD heterozygote state. The neurologic condition in this patient suggests that the diagnosis of ALD should be considered in women with evidence of white matter disease.

Adrenoleukodystrophy↗

Anti-neurofilament protein antibodies in opsoclonus-myoclonus.

Opsoclonus-myoclonus (OM) is a neurological disorder usually occurring in infancy, clinically manifested by various involuntary movements. The pathogenesis of OM is unknown, but since the disease often is associated with viral infection or with neuroblastoma, an immunologic basis for OM has been postulated. We have studied two children with OM whose serum contained antibodies directed against the 210 kDa neurofilament protein; these antibodies were not seen in the serum of 21 children with other neurological disorders. Neurofilament proteins, which are found only in neurons, may be of prime importance in neuronal function, especially during development of the nervous system. Our findings suggest that generation of antibodies to the neurofilament proteins can occur in patients with opsoclonus-myoclonus; the role of the anti-NF210K antibodies in the pathogenesis of OM, however, is uncertain.

Autoantibodies↗

Neonatal adrenoleukodystrophy: new cases, biochemical studies, and differentiation from Zellweger and related peroxisomal polydystrophy syndromes.

Eight new cases of autopsy-confirmed or suspected neonatal adrenoleukodystrophy (NALD) are presented together with new biochemical data on very-long-chain fatty acids (VLCFA) and plasmalogens and a review of all previously published cases. The clinical, biochemical, and histopathologic abnormalities characteristic of this newly recognized form of adrenoleukodystrophy are analyzed in detail and compared to the principal characteristics of the similar disorder, the cerebrohepatorenal syndrome of Zellweger (ZS). Using strict pathologic criteria for the diagnosis of NALD, we find that, despite many clinical resemblances, NALD and the ZS are distinguishable on the basis of histology and peroxisomal biochemistry. Patients with NALD demonstrate adrenal atrophy, systemic infiltration by abnormal lipid-laden macrophages, and elevations of saturated VLCFA. In contrast, patients with ZS have chondrodysplasia, glomerulocystic disease of the kidney, central nervous system dysmyelination, and elevations of unsaturated as well as saturated VLCFA, but they lack adrenal atrophy. We conclude that NALD and the ZS probably represent at least two different genetic defects.

Abnormalities, Multiple↗

Appearance and phosphorylation of the 210 kDalton neurofilament protein in newborn rat brain, spinal cord, and sciatic nerve.

The appearance and in vivo phosphorylation of the 210 kDalton (kD) neurofilament protein (NF210K) in newborn rat brain, spinal cord, and sciatic nerve were investigated. Electron microscopic examination of neurofilaments isolated from newborn rat brain and spinal cord demonstrated morphologically distinct filaments which contained cross-bridging side arms. Neurofilament proteins, phosphorylated in vivo, were separated by sodium dodecyl sulfate slab gel electrophoresis and were transferred from acrylamide gels to nitrocellulose sheets. The nitrocellulose sheets were treated with antiserum to the 70 kD, 145 kD and 210 kD neurofilament proteins by the immunoblot technique. The three neurofilament proteins were found to be present in newborn brain, spinal cord and sciatic nerve. The presence of NF210K in newborn rat brain was further confirmed by 2-dimensional gel electrophoresis followed by identification of this protein by the immunoblot technique. Exposure of the immunostained nitrocellulose sheets to x-ray film revealed that the NF210K, NF145K, and NF70K proteins were phosphorylated in filaments prepared from newborn rat central and peripheral nervous systems. These results suggest that the synthesis and posttranslational modification of the neurofilament proteins may be synchronized or developmentally regulated. It is feasible that phosphorylation of the NF210K subunit may be a prerequisite for the formation of neurofilament cross-bridging elements which are necessary for radial growth of axons.

Animals↗

Immunoblot identification of glial fibrillary acidic protein in rat sciatic nerve, brain, and spinal cord during development.

The appearance of the glial fibrillary acidic protein (GFAP) during embryonic and postnatal development of the rat brain and spinal cord and in rat sciatic nerve during postnatal development was examined by the immunoblot technique. Cytoskeletal proteins were isolated from the central and peripheral nervous system and separated by SDS slab gel electrophoresis or two-dimensional gel electrophoresis. Proteins from the acrylamide gels were transferred to nitrocellulose sheets which were treated with anti-bovine GFAP serum and GFAP was identified by the immunoblot technique. GFAP was present in the embryonic rat brain and spinal cord at 14 and 16 days of gestation respectively. The appearance of GFAP at this stage of neural development suggests that the synthesis of GFAP may be related to the proliferation of radial glial cells from which astrocytes are derived. It is also feasible that GFAP provides structural support for the radial glial cell processes analogous to its role in differentiated astrocytes. GFAP was found to be present in rat sciatic nerves at birth and at all subsequent stages of development. These results indicate that some cellular elements in the rat sciatic nerve, such as Schwann cells, are capable of synthesizing GFAP which is immunochemically indistinguishable from its counterpart in the central nervous system. Thus it appears that GFAP is present both in the central and peripheral nervous system of the rat when the glial cells synthesizing GFAP are still undergoing differentiation.

Animals↗

Hydrocephalus and mental retardation in craniosynostosis.

We prospectively studied craniosynostosis, regardless of neurologic status, by cranial computed tomography or psychometric testing in 56 children. None of the 27 children with simple craniosynostosis (single or multiple suture involvement) had evidence of hydrocephalus on CT scan. Of the 24 patients with simple craniosynostosis who underwent psychometric testing, 17 were of average intelligence; six were in the low average range. The single mentally retarded child had a history of severe perinatal asphyxia. Hydrocephalus occurred more frequently (five of 23 cases) in children with complex craniosynostosis syndromes, including Pfeiffer syndrome, Crouzon syndrome, and kleeblattschädel deformity. More striking than hydrocephalus, however, was the finding of dysmorphic ventricular dilation in eight patients, including the three children with Apert syndrome and four with Crouzon syndrome. Nineteen of the 25 children with complex craniosynostosis syndromes receiving psychometric testing were of normal intelligence. Four children with borderline normal intelligence had either hydrocephalus or ventricular dilation. The two children with mental retardation were sisters with Crouzon syndrome whose family included other retarded individuals. This study indicates that the incidence of hydrocephalus and mental retardation in craniosynostosis is lower than reported previously.

Acrocephalosyndactylia↗

Theophylline neurotoxicity resulting in significant unilateral brain-damage.

A case of theophylline neurotoxicity in a three-month-old infant is reported. Prolonged focal seizures with secondary generalization resulted in hemiparesis and developmental retardation, and CT demonstrated cerebral hemiatrophy. Later the infant developed recurrent focal and atonic convulsions, which were refractory to multiple anticonvulsants. Possible etiological factors, especially the pharmacological mechanisms by which theophylline can produce focal convulsions and result in brain damage, are discussed.

Brain Damage, Chronic↗

Shunt fluid examination: risks and benefits in the evaluation of shunt malfunction and infection.

A combined retrospective and prospective study was designed to assess the efficacy of shunt fluid examination in the evaluation of shunt malfunction and/or infection, and to ascertain the complication rate associated with this procedure. Ninety-one patients with shunts for the treatment of hydrocephalus underwent a total of 209 diagnostic shunt "taps." Of 72 instances of mechanical obstruction documented at surgery, 70 were correctly identified by abnormal shunt fluid dynamics, either an opening cerebrospinal fluid (CSF) pressure in excess of the expected valve pressure or absent flow of fluid. The organisms responsible for 12 of 13 shunt-related infections were correctly isolated on initial and all subsequent shunt fluid cultures obtained prior to the institution of appropriate antibiotics. With one infection, a bacterial pathogen was not identified until the third tap. In all instances in which lumbar or ventricular CSF, blood, or wound cultures disclosed an organism, shunt fluid cultures also identified the agent. In addition, these procedures were less reliable. No complications occurred during or immediately following any of the shunt taps. Long-term consequences were assessed in 53 patients with an average follow-up period of 26 months. Some shunt systems subsequently required revision and two infections were documented. The uniformly long interval between the shunt fluid examination and these complications makes it unlikely that the taps contributed to the development of malfunction or infection. Shunt fluid examination appears to be a simple, benign, and yet accurate means of diagnosing shunt malfunction and/or shunt-related infection.

Cerebrospinal Fluid↗

Progressive CT abnormalities despite clinical improvement in SSPE treated with inosiplex.

Inosiplex has been utilized in the treatment of subacute sclerosing panencephalitis (SSPE), though without unequivocally established beneficial effect. We report a patient whose computerized tomographic (CT) scans demonstrated the development of progressive cerebral atrophy and multifocal white matter lesions despite continuous treatment with inosiplex and periods of considerable clinical improvement or stabilization. The findings suggest that inosiplex may not have altered the pathological consequences of SSPE and that clinical staging categories alone may not be reliable long-term correlates of the progression of the disease. Controlled studies utilizing assessment of brain mass by CT scan or other imaging devices in addition to clinical staging are required to evaluate the efficacy of inosiplex.

Adolescent↗

Presumptive long arm deletion of chromosome 8: a new syndrome?

This communication describes an infant with growth and psychomotor retardation and severe congenital malformations, who was found to have an interstitial deletion of the long arm of chromosome 8: 46,XY,del(8) (q13q22). Comparison with the only other previously reported patient with a deletion of a similar chromosomal segment suggested that deletion of the long arm of chromosome 8 may constitute a clinically recognizable syndrome.

Abnormalities, Multiple↗

Pseudotumor cerebri associated with obstructive nephropathy.

We report two infants with pseudotumor cerebri associated with renal disease. The pathogenesis of increased intracranial pressure in this clinical setting is unclear, but may be mediated by one or more of the conditions commonly associated with pseudotumor cerebri, including sinus thrombosis, increased intravascular fluid volume, anemia, and endocrine disturbances resulting in abnormal calcium and phosphorus metabolism. The onset of pseudotumor cerebri also may be related to changes in vasopressin levels that affect brain water permeability.

Acidosis, Renal Tubular↗

Recurrent coma and Lesch-Nyhan syndrome.

A patient with Lesch-Nyhan syndrome has had 3 recurrent episodes of coma, each associated with an acute illness. Extensive investigation for known causes of coma has failed to yield a diagnosis. Although coma is not generally recognized as a feature of Lesch-Nyhan syndrome, similar patients have been reported previously. This and other episodic phenomena observed in Lesch-Nyhan syndrome may be explained by the disruption of cellular energy metabolism due to purine depletion, consequent to lack of the purine salvage pathway normally provided by the hypoxanthine-guanine-phosphoribosyl-transferase enzyme.

Coma↗

Brain uptake and utilization of fatty acids: recommendations for future research.

A primary goal of the international workshop "Brain Uptake and Utilization of Fatty Acids" was to identify research areas that would benefit from further investigation. The major themes for future research are presented below: (1) Elucidating the role of the developing and mature cerebrovascular endothelium (CVE) in the uptake of fatty acids (FA) into the brain. (2) Clarifying the role of diffusion and receptor-mediated uptake of FAs by various brain cell membranes and protein-mediated shuttling of FAs between the CVE and various brain cells and tissues. (3) Illuminating the mechanisms of intermediate metabolism and the roles of polyunsaturated fatty acids (PUFA) in astrocytes, neurons and oligodendrocytes. Of special interest are the long-chain omega-3 PUFA and their derivatives, such as lipoproteins, phospholipids and plasmalogens, that have been associated with various disease states (such as those listed in [5], below). (4) Elucidating the role of gene expression on long-chain omega-3 PUFA incorporation in membranes and the regulatory role these and other PUFA have on gene expression in the brain. (5) Elucidating the recently identified roles of long-chain omega-3 PUFA in mood disorders, schizophrenia, stroke, peroxisomal biogenesis disorders, Huntington's disease, other neurodegenerative disorders and disorders of oxidative stress. (6) Undertaking placebo-controlled clinical trials to assess the therapeutic potential of omega-3 PUFA in the above disorders. (7) Developing new, and utilizing existing animal models in the above studies. (8) Developing noninvasive imaging and tagging methods for quantifying the migration and distribution of PUFA and their derivatives in the brain. (9) Applying multi-disciplinary collaborations among biophysicists, physiologists and molecular biologists to the resolution of the above.

Animals↗

Brain uptake and utilization of fatty acids: applications to peroxisomal biogenesis diseases.

The brain is rich in diverse fatty acids saturated, monounsaturated and polyunsaturated fatty acids with chain lengths ranging from less than 16 to more than 24 carbons that make up the complex lipids present in this organ. While some fatty acids are derived from endogenous synthesis, others must come from exogenous sources. The mechanism(s) by which fatty acids enter cells has been the subject of much debate. While some investigators argue for a protein-mediated process, others suggest that simple diffusion is sufficient. In the brain, uptake is further complicated by the presence of the blood-brain barrier. Brain fatty acid homeostasis is disturbed in many human disorders, as typified by the peroxisomal biogenesis diseases. A workshop designed to bring together researchers from varied backgrounds to discuss these issues in an open forum was held in March, 2000. In addition to assessing the current state of knowledge, areas requiring additional investigation were identified and recommendations for future research were made. A brief overview of the invited talks is presented here.

Animals↗