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Biomedical subjects

L E Becker

Publications and source records attributed to L E Becker.

At least 19 recordsLinked to original sources
PubMed1995

Prenatal diagnosis of retinal nonattachment in the Walker-Warburg syndrome.

We report on the prenatal ultrasonographic diagnosis of Walker-Warburg syndrome based on cerebral and ocular findings. The ultrasound study done at 37 weeks gestation documented hydrocephalus and retinal nonattachment consistent with this syndrome. The ability to detect retinal nonattachment prenatally may have implications for the prenatal diagnosis of other conditions which have early retinal nonattachment as one of their findings. However, it is uncertain how early in pregnancy this defect can be detected.

Abnormalities, Multiple↗
PubMed1995

Neuroimaging studies in children with temporal lobectomy.

Twenty-eight children with intractable seizures who subsequently underwent a temporal lobectomy were studied by electroencephalogram (EEG), prolonged video EEG telemetry, computed tomography (CT), magnetic resonance imaging (MRI), and single photon emission computed tomography (SPECT) for the localization of epileptogenic foci. MRI showed abnormalities indicating epileptogenic foci in 21/25 patients and a increased signal intensity in 7/11 patients with mesial temporal sclerosis (MTS). SPECT showed corresponding abnormalities in 17/22 patients, including an interictal decrease in regional cerebral blood flow corresponding to the epileptogenic zone in 15. CT showed localized abnormalities in 16/28. All 12 patients with benign, slow-growing neoplasms showed an abnormality on CT scan. In children, MRI is essential in localizing epileptogenic abnormalities, especially MTS and cortical dysplasia. SPECT contributes to the localization of epileptogenic foci, which are often coincident with EEG abnormalities, particularly in single pathology. CT depicts benign neoplasms with calcification in the temporal lobe, which are likely to provoke complex partial seizures.

Adolescent↗
PubMed1995

Arthrogryposis multiplex congenita due to congenital myasthenic syndrome.

Two children, now 5 1/2 and 6 years of age, presented as neonates with hypotonia, multiple joint contractures, ptosis, extraocular weakness, bulbar symptoms, and respiratory distress. Fluctuations and episodic exacerbations of weakness necessitated respiratory support. Both children are developmentally delayed and cannot walk independently, although one child underwent bilateral tenotomies. Biochemical investigations and electromyography, including slow-rate, repetitive nerve stimulation, were normal. Acetylcholine receptor antibodies in serum were absent. Single-fiber electromyography with axonal stimulation revealed prolonged mean jitter in the tibialis anterior and extensor digitorum muscles, with more than 2 abnormal individual jitter values in each muscle. Muscle biopsy demonstrated normal pattern and morphology of muscle fibers; immunohistochemical staining for cholinesterase was positive. Electron microscopy revealed abnormalities in motor endplates: atrophy, flattening of primary synaptic clefts, and paucity of side branches. These findings represent one of the postsynaptic abnormalities (i.e., acetylcholine receptor deficiency or paucity of synaptic folds). Both children improved clinically on pyridostigmine therapy. Arthrogryposis congenital multiplex due to congenital myasthenic syndrome, as diagnosed in our patients, has been reported once before. The diagnosis can be established by clinical history, neurologic examination, and electrophysiologic and pathologic findings. Clinical improvement can be achieved with high-dose anticholinesterase therapy.

Arthrogryposis↗
PubMed1995

Chronic encephalitis and epilepsy (Rasmussen's encephalitis): detection of cytomegalovirus and herpes simplex virus 1 by the polymerase chain reaction and in situ hybridization.

We made a pathologic diagnosis of chronic encephalitis on surgical resections or autopsy material in 10 patients with intractable seizures and studied the specimens by immunohistochemistry for herpes simplex virus (HSV) 1 and 2 and cytomegalovirus (CMV) as well as by the polymerase chain reaction (PCR) for viral DNA sequences (HSV1, HSV2, and CMV). We also assessed eight patients (nonepileptic) with pathologically documented or clinically suspected encephalitis and five resections from epileptics without encephalitis. Immunohistochemistry for viral antigens was negative in all cases. Using PCR assay, CMV was present in six and HSV1 in two of 10 epilepsy patients with chronic encephalitis. We demonstrated CMV by in situ hybridization in two of the six patients positive for CMV by PCR. We found no viral sequences by PCR in five epileptics without encephalitis. Of the eight patients (nonepileptic) with clinically suspected or pathologically confirmed encephalitis, two cases showed CMV sequences by PCR. These observations suggest that PCR allows detection of viral sequences in some cases of chronic encephalitis associated with epilepsy that may be missed by in situ hybridization.

Adolescent↗
PubMed1995

Nasal glioma: is dermis involvement significant?

Nasal gliomas are rare, benign, congenital masses more accurately referred to a sequestered glial tissue. Seven patients with nasal glioma treated by Hugh G. Thomson over the last 28 years are presented with special reference to tumor recurrence after excision and associated naso-ocular cleft. Three of our patients had an associated ipsilateral naso-ocular cleft, and three similar cases have been reported. This association is probably more frequent because a naso-ocular cleft can exist as a forme fruste and be easily overlooked. The first two tumors resected in our series recurred within 10 months; however, no recurrences were seen after a new treatment protocol was initiated in 1972. This consisted of total excision of the skin overlying the tumor if the skin adhered to the mass or if glial elements were seen within the dermis on frozen section. Deep resection margin was also assessed by frozen section of the nasal mucosa or fibrous stalk of the tumor. Accordingly, unnecessary intracranial procedures were avoided without increasing the risk of recurrence.

Abnormalities, Multiple↗
PubMed1994

Cerebral and cerebellar gangliocytomas: a morphological study of nine cases.

Hypothalamic gangliocytomas have been shown to contain immunoreactivity for hypophysiotropic peptides and some have been associated with endocrine dysfunction. Extrahypothalamic gangliocytomas are usually not associated with endocrine abnormalities. We studied nine cerebral or cerebellar gangliocytomas from six men and three women; none of the patients had detectable alterations of endocrine homeostasis. On histological examination, the tumor cells resembled hypothalamic neurons. Electron microscopy disclosed the presence of dense-core vesicles in neuronal cytoplasm and processes resembling Herring bodies, and there were synaptic contacts between tumor cells. All but two tumors contained immunocytochemical positivity for at least one peptide hormone or amine; these included somatostatin, corticotropin-releasing hormone, beta-endorphin, galanin, vasoactive intestinal peptide, calcitonin, serotonin, catecholamines or met-enkephalin. These tumors have been thought to represent neoplasms arising in ectopic autonomic neural tissue. Their morphological features, their similarity to hypothalamic gangliocytomas and the multiple immunoreactivities shown here suggest that they can be regarded as tumors of peptidergic neurons that are widely distributed throughout the central nervous system.

Adolescent↗
PubMed1994

Neuronal intranuclear hyaline inclusion disease with progressive cerebellar ataxia.

Neuronal intranuclear hyaline inclusion disease is a progressive, fatal neurologic condition characterized by eosinophilic inclusions in neurons of the central, autonomic, and peripheral nervous systems. The clinical and pathologic findings of a 4-year-old boy who presented with a rapidly progressive cerebellar ataxia and seizure disorder that had begun 2 years earlier are described. Although intraneuronal inclusions were identified in neurons of cortex, basal ganglia, brainstem, cerebellum, and spinal cord, clinical signs were restricted to cerebellar ataxia, internuclear ophthalmoplegia, and cognitive delay. Predominant cerebellar atrophy, early age of onset, and short clinical course distinguishes it from previously reported patients.

Atrophy↗
PubMed1994

Aberrant distribution of tyrosine hydroxylase and substance P in infants with brain-stem infarction.

The distribution of tyrosine hydroxylase (TH) and substance P (SP) was examined in the brain-stem of 4 infants with respiratory abnormalities associated with remote brain-stem or cerebellar infarction utilizing immunohistochemical methods. TH-immunoreactive cells and SP-immunoreactive fibers were found in and around the area of the infarction in the tegmentum, in amounts and sites different from that seen in controls. The aberrant localization of SP and TH may represent an altered repair process associated with resolution of the infarction and may be related to abnormal respiratory control or sudden death.

Brain Stem↗
PubMed1994

Neuropathology and immunohistochemistry of the brain-stem in neonates with congenital hydrocephalus: comparative studies between aqueductal stenosis and Arnold-Chiari malformation.

Neuropathological and immunohistochemical studies were done on the brain-stem of neonates who had congenital hydrocephalus with aqueductal stenosis or Arnold-Chiari malformation (ACM). The infants with aqueductal stenosis showed heterogeneity in their clinicopathological findings while the infants with ACM were relatively similar in neuropathological findings. There were prominent astrogliosis, decreased immunoreactivity with antisera to tyrosine hydroxylase and myelin basic protein in the periaqueductal area, and an increased reactivity with antiserum to substance P in the tegmentum of most patients with aqueductal stenosis and other malformations. In ACM, there was little gliosis in the tegmentum and periaqueductal area and minimal immunoreactivity of tyrosine hydroxylase, myelin basic protein and substance P. In both groups of cases, the cells in the periaqueductal region differ in neurotransmitter/neuromodulator immunoreactivity and degree of myelination reflecting a difference possibly in their maldevelopment.

Arnold-Chiari Malformation↗
PubMed1993

Correlation of astrogliosis and substance P immunoreactivity in the brainstem of victims of sudden infant death syndrome.

Substance P is a neuropeptide localized to selected neurons some of which may be involved in respiratory regulation. Substance P appears to be increased in the brainstem under conditions of hypoxia. A quantitative analysis of immunoreactivity to glial fibrillary acidic protein and substance P in the pons of 20 SIDS victims showed astroglial proliferation in the reticular formation and pontine nuclei and an increase of substance P in trigeminal fibers compared with age-matched controls. These observations suggest that in SIDS the neurons in the vicinity of the astrogliosis may be altered as indicated by the apparent increased expression of substance P, although the functional significance of this change on respiratory control is undetermined.

Astrocytes↗
PubMed1992

Fatal combined defects in mitochondrial multienzyme complexes in two siblings.

A female child suffering from intrauterine growth retardation was born by caesarean section at 32 weeks. In the immediate newborn period there was a metabolic acidosis but this resolved. Hypotonia, muscular weakness and poor respiratory effort were evident and the child died at 6 days of age. A previous male sibling had died at 3 months of age after similar symptoms with seizures and a dysmyelination disorder. Post-mortem examination of both children showed damage to the basal ganglia. Defects in the activities of the pyruvate dehydrogenase complex, cytochrome oxidase and succinate cytochrome c reductase were found in cultured skin fibroblasts. Similar defects were found in isolated muscle mitochondria but not in isolated liver mitochondria from the patient. Immunoblotting for cytochrome oxidase showed that the multienzyme complex was not assembled in muscle and skin fibroblast mitochondria, but was assembled in liver mitochondria. Similar results were obtained in cultured skin fibroblast mitochondria for complex I of the mitochondrial respiratory chain. This is the first occasion that multiple defects have been demonstrated both in tissue and in culture skin fibroblasts in mitochondrial respiratory chain complexes.

Abnormalities, Multiple↗
PubMed1992

Development of myelinated and unmyelinated fibers of human vagus nerve during the first year of life.

As an important component of cardiorespiratory control, the vagus nerve and its maturation were evaluated in normal infants in order to provide standards of comparison with infants with dysfunctional neural control mechanisms. Myelinated and unmyelinated fibers in the cervical vagus nerve were examined in 27 term infants. Number of fibers, axon diameters, and myelin thickness were compared among four age groups. The histograms of axon size exhibited a skewed distribution that persisted during the age range examined for both myelinated and unmyelinated vagus fibers. Fiber size distributions of myelinated fibers, however, already showed an incipient multimodal distribution after 3 months. No major increase was observed in the average axon size of myelinated and unmyelinated fibers. A significant increase was observed, however, in the average content of myelin in myelinated fibers expressed as myelin thickness, number of lamellae or g ratio (internal/external diameter). These results suggest an active myelination during the first 9 months of life without a major change in the axonal characteristics of the fibers. A marginal increase in the density of myelinated fibers with age, both in terms of total number and the relation to unmyelinated fibers, suggests a slow transition from unmyelinated to myelinated fibers during the first year of life, particularly during the first 3 months. The present morphometric parameters indicate an active deposition of myelin before the maturation of cross-axonal dimensions. The distribution of g ratios also suggests that optimal conduction velocity is compromised only in a fraction of all vagal myelinated fibers.

Aging↗
PubMed1992

Detection and management of gangliogliomas in children.

Forty-two children treated for gangliogliomas were reviewed to identify the best methods of detection and management. Thirty-two of the tumors were supratentorial, four infratentorial, and six were in the spinal cord. Twenty-five patients presented with seizures; the mean duration of symptoms was 5 years in contrast to 1 year in non-seizure patients. Of 31 children studied by computed tomography (CT), calcification in the tumor lesion was found in 19. Magnetic resonance imaging (MRI) showed abnormal high-signal intensity on T2 imaging in six of eight patients. All patients underwent surgical resection and were diagnosed pathologically. Twenty-four patients had total resection, and 14 underwent temporal lobectomies including hippocampectomy. The management of this tumor remains surgical resection without the need for any adjuvant therapy.

Adolescent↗
PubMed1992

Vascular dysplasia in Down syndrome: a possible relationship to moyamoya disease.

The brain of a child with Down syndrome (DS) and vascular abnormalities is described. Neuropathological examination showed a large cerebral infarction. In the circle of Willis there was hypoplasia of the left middle and posterior communicating cerebral arteries, and microscopically there was thickening of intima and focal disruption of internal elastica in some areas of the circle of Willis. Several reports suggest that the incidence of moyamoya disease is higher in children with DS than in other children. The high incidence of congenital heart disease in DS suggests an abnormality of vascular development that may manifest intracranially as a structural vascular defect, creating a vulnerability to unknown factors important in the pathogenesis of the moyamoya abnormality.

Blood Vessels↗
PubMed1992

Experimental verocytotoxemia in rabbits.

The clinicopathologic effects of intravenously administered purified verocytotoxin 1 (VT1; Shiga-like toxin 1) in 2-kg male rabbits was studied. The 50% lethal dose was 0.2 micrograms of protein per kg of body weight (2 x 10(4) 50% cytotoxic doses per kg). The clinical features included nonbloody diarrhea and a progressive flaccid paresis, usually culminating in death. The histopathology was characterized by edema and hemorrhage in the mucosa and submucosa of the cecum and edema, hemorrhage, and neuronal necrosis in the brain and gray matter of the spinal cord. Thrombotic microangiopathy, the characteristic histopathologic renal lesion in the hemolytic-uremic syndrome, was also found to be the underlying lesion in verocytotoxemic rabbits. To determine the specific distribution of VT1 in rabbit tissues, purified 125I-labelled VT1 was administered intravenously to 20 rabbits (both immunologically naive and VT1-immune rabbits). The highest specific uptake of 125I-VT1 was in the spinal cord, brain, cecum, colon, and small bowel in unimmunized animals but in the liver, spleen, and lungs in immune animals. Immunofluorescent staining of cecal and spinal cord tissues after intravenous administration of VT1 showed evidence of specific vascular endothelial cell binding of the toxin. The striking correlation of the central nervous system and gastrointestinal localization of 125I-VT1 with the sites of known histopathology is consistent with direct toxin-mediated injury to these tissues, initiated by the specific binding of VT1 to the vascular endothelium. We conclude that the vascular damage induced by VT1 in affected rabbit tissues is similar to that seen in the kidneys and other tissues in patients with verocytotoxin-producing Escherichia coli-associated hemolytic-uremic syndrome. This suggests that although the rabbit model fails to replicate human hemolytic-uremic syndrome, it is useful for studying the pathogenesis of the vascular lesions in verocytotoxin-producing E. coli-associated diseases.

Animals↗
PubMed1992

Magnetic resonance imaging evaluation of delayed myelination in Down syndrome: a case report and review of the literature.

Magnetic resonance imaging has been found to be useful in assessing brain myelination and provides information on brain maturation. The normal pattern of brain myelination conforms to a fixed sequence, with good pathologic and MRI correlation. Neuropathologic analysis of myelination has shown delayed central myelination in Down syndrome. Delayed myelination on MRI in Down syndrome has not previously been reported. We report a case of Down syndrome with a significant delay in myelination as demonstrated on MRI. This 18-month-old infant had brain myelination equivalent to that expected for an 11-month-old infant. To determine the relative incidence, extent of delayed myelination, and time for recovery to full myelination in Down syndrome, more cases require examination and assessment. Magnetic resonance imaging has the advantage of serial assessment of myelination during brain maturation.

Brain↗
PubMed1992

Focal midbrain tumors in children.

The clinical and neuroradiological features of focal midbrain tumors in 12 children are described, and the results of their surgical management are presented. Patients with a focal midbrain tumor usually exhibit either symptoms and signs of raised intracranial pressure caused by an obstructive hydrocephalus (50%) or symptoms and signs caused by pressure on the tegmentum and cerebral peduncles. The lesions are confined to the tectal plate or tegmentum with possible extension upward to the thalamus and downward to the pons, displacing but not invading these structures. The edges of the tumor are well defined, and the large majority have a solid consistency with intense regular enhancement after intravenous contrast. Radical resection is hardly ever feasible in brain stem tumors, but in this series, significant reduction of the tumor mass was obtained in 75% of the patients, with no surgical mortality and minimal surgical morbidity and with the majority of patients showing clinical improvement postoperatively. All tumors were nonpilocytic, low-grade astrocytomas. Six patients received adjunctive radiotherapy. The mean follow-up period is 2.5 years, and all patients are alive and doing well. We conclude that focal midbrain tumors in children appear to be a distinct subgroup of brain stem tumors and are very amenable to surgical resection with an excellent long-term prognosis.

Adolescent↗