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Biomedical subjects

L E Becker

Publications and source records attributed to L E Becker.

At least 73 records · Page 4Linked to original sources
PubMed1996

Vagal nerve complex in normal development and sudden infant death syndrome.

BACKGROUND: Although the pathogenesis of sudden infant death syndrome (SIDS) is not understood, one of the major hypotheses is that a subtle defect in respiratory circuitry is an important underlying factor. The vagus nerve is a critical component of respiratory control, but its neuroanatomic complexity has limited its investigation in human disease. METHODS: Correlating developmental studies on different parts of the vagus nerve allows a more comprehensive assessment of its maturation process. Comparison of the normal developing vagus nerve with nerves examined in SIDS patients suggests alterations in the nucleus tractus solitarius and dorsal vagal nucleus as well as in the peripheral vagus nerve. RESULTS AND CONCLUSIONS: The persistence of dendritic spines and lack of appropriate axonal growth implies delays in vagal maturation. Since nodose ganglia can be examined in vitro from autopsy material, perturbation to this system can be explored to evaluate further the mechanism involved in terminal vagal maturation. Although the reason for the delayed vagal maturation in SIDS is not apparent, the presence of astrogliosis in the region of the vagal nuclei is consistent with an exposure to hypoxic-ischemic events some time before death.

Humans↗
PubMed1996

A classification scheme for malformations of cortical development.

Malformations of the cerebral cortex are being recognized more frequently as a cause of epilepsy, developmental delay, neurological deficits, and mental retardation. Nonetheless, a standard nomenclature and classification system of these malformations, based upon state-of-the art knowledge derived from genetics, embryology, imaging, and pathology, has not been devised. In this manuscript, we propose such a classification system. Moreover, we have constructed the system such that both the framework and the classifications themselves are flexible and can be adapted as our knowledge of the embryology, genetics, imaging, and pathology of these disorders advances. We believe that the use of this classification system will help both clinicians and researchers to understand and think about these disorders and their causes better. In turn, we hope that this improved understanding will lead to further refinements in classification, to advances in our knowledge and, ultimately, to improvements in therapy.

Brain Damage, Chronic↗
PubMed1996

A neutrophilic drug reaction to Clomid.

A 33-year-old woman treated for infertility with multiple courses of clomiphene citrate (Clomid) presented with the complaint of a rash with every course of the medication. Examination revealed petechiae and palpable purpura on her lower extremities which, histologically, were found to be consistent with a neutrophilic drug reaction. The clinical course of this unusual presentation, as well as a brief review of the neutrophilic dermatoses, are provided.

Adult↗
PubMed1996

Hepatitis C and porphyria cutanea tarda.

Porphyria cutanea tarda (PCT) is a clinical manifestation of decreased uroporphyrinogen decarboxylase (UPD) activity. Multiple endogenous and exogenous factors have been implicated in inducing PCT in genetically predisposed patients. The most recent is the RNA virus hepatitis C (HCV), which is transmitted via blood exposure. The mechanism of action in HCV-induced PCT is unknown but produces the same clinical, laboratory, and histopathologic changes seen in other forms of sporadic PCT. Therefore, patients presenting with PCT clinically should be tested serologically for antibodies against HCV and patients with HCV should be monitored for signs and symptoms of PCT.

Adult↗
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

Intracerebral vascular occlusion in familial erythrophagocytic lymphohistiocytosis: a case report of two siblings.

Neuropathological findings in two siblings with familial erythrophagocytic lymphohistiocytosis (FEL) are reported. Case 1 showed the typical neuropathological findings of FEL with lymphohistiocytic infiltration of the leptomeninges and perivascular spaces. A characteristic erythrophagocytosis was detected in inguinal lymph nodes, lung and bone marrow. Case 2 revealed calcification and necrotic lesions in the brain. In the necrotic areas, parenchymal calcification, vascular medial calcification, and occlusion of many vessels due to subendothelial fibrosis were detected. The areas of necrosis correlated with the distribution of occluded vessels. These changes were most prominent in putamen, internal capsule, thalamus and dentate nucleus. Hypercytokinemia is suspected to be the underlying mechanism for the clinical and laboratory findings in patients with FEL, although the relationship to the vascular pathology is unclear.

Arterial Occlusive Diseases↗
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

Central neuronal tumors in childhood: relationship to dysplasia.

A survey of 1,500 brain tumors at The Hospital for Sick Children in Toronto reveals that about 20-25% of tumors demonstrate some form of neuronal differentiation. At one end of the spectrum are the well-defined ganglionic tumors, sometimes difficult to differentiate from cortical dysplasia. At the other extreme are primitive neuroectodermal tumors with neuronal differentiation often confined to immunohistochemical observations. Of the total number of tumors, approximately 5% have a definitive ganglionic component, the majority being ganglioglioma, and others include dysembryoplastic neuroepithelial tumor, infantile ganglioglioma, paraganglioma, central neurocytoma, and gangliocytoma. Some tumors such as subependymal giant cell tumor associated with tuberous sclerosis occasionally have evidence of neuronal differentiation with immunoreactivity with antisera to neuron-specific enolase and negativity with antisera to GFAP. In children with epilepsy, improved brain imaging has identified lesions which on examination following temporal lobectomy show varying degrees of cortical dysplasia. At this site, there is also a high incidence of gangliogliomas. Is there a relationship between cortical dysplasia and neuronal tumors? Following a primary induction event during development, embryonal dysplasia and/or neoplasia may occur. The lesion may be malformative as in unilateral megalencephaly, hamartomatous as in tuberous sclerosis, neoplastic as in congenital tumors, or a combination of malformative and neoplastic.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
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

Neonatal posthemorrhagic hydrocephalus: neuropathologic and immunohistochemical studies.

A neuropathologic study was undertaken to examine associated brain damage in patients with fetal and neonatal posthemorrhagic hydrocephalus (PHH). In PHH the association of periventricular leukomalacia and pontosubicular necrosis was not increased, but that of cerebellar subarachnoid hemorrhage and olivo-cerebellar pathology was significantly increased. All patients with the olivocerebellar pathology exhibited associated cerebellar subarachnoid hemorrhage and loss of Purkinje cells. Ferritin-positive glia were increased in the molecular layer of most patients, and glial fibrillary acidic protein-positive glia and/or fibers were increased in the molecular layer, granular layer, and white matter in older infants. Neonates with PHH had more severe brain lesions than those with only intraventricular hemorrhage. At 2 weeks of age in PHH, the ventricular wall displayed hemosiderin deposits and nodular gliosis, with ependymal cell loss and subependymal rosette formation. These findings may be closely related to the underlying pathogenesis and neurologic sequelae of PHH.

Brain Stem↗
PubMed1995

Surgical pathology of epilepsy resections in childhood.

In this review, we discuss the important pathological lesions observed in temporal lobectomies and neocortical resections performed for medically refractory seizures in children. A higher percentage of pediatric cases appear to be "lesional" with computed tomography (CT) and magnetic resonance imaging (MRI) and abnormalities and "dual pathology" lesions appear to be more common than pure mesial temporal sclerosis. Almost a third of cases appear to be neuronal migration disorders and low-grade gliomas with some lesions harboring both neoplastic and malformative components. Our experience suggests a role for cytomegalovirus in some cases of Rasmussen's encephalitis.

Brain Injuries↗
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

Effects of antisense glial fibrillary acidic protein complementary DNA on the growth, invasion, and adhesion of human astrocytoma cells.

Glial fibrillary acidic protein (GFAP)-positive astrocytoma cells were stably transfected with an expression vector carrying a murine complementary DNA for GFAP in the antisense orientation. Three stably transfected GFAP-negative transformants were identified by indirect immunofluorescence and expanded in vitro. The stably transfected and control cell clones were analyzed for morphological alterations, growth in monolayer and soft agar, adhesiveness, and in vitro invasive potential. In contrast to control astrocytoma cells which retained an astrocytic phenotype with polygonal or triangular cells extending multiple long and thin processes, the antisense GFAP-transfected cells demonstrated marked morphological alterations in the form of flat, epithelioid cells devoid of long, astrocytic glial processes. The antisense GFAP-transfected clones demonstrated a greater degree of cell crowding and piling at confluence than did controls. By tritiated thymidine analysis, the antisense GFAP-transfected cell clones demonstrated a 2-3-fold increase in incorporation of the radiolabel, suggesting an enhanced proliferative potential over controls. Antisense GFAP-transfected astrocytoma clones formed larger and more numerous colonies than did controls when tested for anchorage-independent growth in soft agar. Following a time-course adhesion assay, antisense GFAP-transfected astrocytoma clones were found to be less adherent to their substratum than controls. When assessed in an in vitro invasion assay system, antisense GFAP-transfected astrocytoma cells more readily penetrated Matrigel-coated filters than did controls. These data have shown that eliminating GFAP expression from astrocytoma cells has affected astrocytoma cell morphology and adhesion. The data also suggest that the growth and invasive potential of the antisense GFAP-transfected astrocytoma cells have been significantly enhanced by altering the expression of this glial-specific cytoskeletal protein in this experimental cell system.

Animals↗
PubMed1994

Malignant transformation in a ganglioglioma with anaplastic neuronal and astrocytic components. Report of a case with flow cytometric and cytogenetic analysis.

BACKGROUND: Malignant transformation of a ganglioglioma is rare and is generally restricted to the glial component. The authors described a unique case in which neuronal and glial elements exhibited anaplasia in a ganglioglioma. A subtotal resection of a large left temporal tumor extending into the diencephalon and brain stem in a 10-year-old boy revealed a ganglioglioma with no atypical features. The histologic findings were unchanged at further resections 4 and 12 months later. Radiotherapy was instituted with 5500 cGy in 30 fractions 21 months after initial resection. The patient returned 3 years later with a massive midline tumor recurrence. METHODS: The tumor was studied by conventional histologic methods, immunohistochemistry, flow cytometric methods, transmission electron microscopy, immune electron microscopy, and cytogenetic analysis. RESULTS: Although the first three resections revealed a typical ganglioglioma, the fourth resection revealed a cellular pleomorphic tumor with many multinucleated cells and mitoses. The tumor cells expressed glial fibrillary acid protein (GFAP) and synaptophysin on double labeling. By electron microscopy, intermediate filaments, microtubules and abundant rough endoplasmic reticulum, and neurosecretory granules were seen. Immune electron microscopy showed GFAP and synaptophysin within tumor cells. Flow cytometric studies revealed G0G1, 78%; S-phase, 9%; and G2M, 13%. Tumor cytogenetics on short term cultures revealed a complex abnormal karyotype with three sublines containing several structural chromosomal abnormalities. CONCLUSIONS: A unique anaplastic transformation of a ganglioglioma is reported with the anaplastic cells exhibiting neuronal and astrocytic features.

Anaplasia↗
PubMed1994

The development of the diaphragm in infants with sudden infant death syndrome.

The morphological development of the skeletal muscle of the diaphragm was studied in normal controls and cases of sudden infant death syndrome (SIDS). Measurements of fiber diameter indicated that the SIDS population had significantly larger diameters for type 1 and type 2 fibers than the control population. The ratio of type 1 to type 2 fibers was found to remain significantly depressed with increasing age in the SIDS population compared with the control population, where it increased linearly to values between 0.8 and 1.2 after 10 months of age. These results suggest an abnormality in the development of the diaphragm of SIDS victims, although its exact nature remains to be determined.

Child, Preschool↗