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Biomedical subjects

L E Becker

Publications and source records attributed to L E Becker.

At least 109 records · Page 6Linked to original sources
PubMed1993

Mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS): clinical, radiological, pathological, and genetic observations.

We reviewed 10 patients (5 males, 5 females) with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The age of symptom onset ranged from 3 months to 12 years. All had lactic acidosis, multiple stroke-like events with secondary neurological deficits, radiological changes of progressive brain infarction, and muscle biopsy showing ragged-red fibers. In patients with earlier onset of symptoms (< 2 yr), involvement tended to be more diffuse, with failure to thrive and early onset of delayed development. Patients whose symptoms appeared later tended to have focal neurological deficits with migraine-like headache, and a rate of cognitive regression reflecting the rapidity of disease progression. Radiological changes included multiple areas of infarction with initial predilection for parietal occipital areas, progressing to generalized atrophy. Pathological findings in muscle biopsies included type 1 fiber predominance, ragged-red fibers, increased intermyofibrillar lipid deposition, and abnormal mitochondria. Four patients showed mitochondrial DNA tRNA mutation at position 3,243. No difference was noted in clinical, radiological, or pathological findings in patients with and without this mutation, suggesting that multiple sites of point mutation may give rise to mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes.

Base Sequence↗
PubMed1993

Developmental changes of S-100 protein and glial fibrillary acidic protein in the brain in Down syndrome.

The location of the gene for the beta subunit of S-100 protein on chromosome 21 suggests that expression may be increased in trisomy 21. Astrocytes from Down syndrome and control patients were examined by immunohistochemistry for the expression of S-100 protein. Adjacent sections were reacted with antisera to glial fibrillary acidic protein to ascertain the presence or absence of astrogliosis. The developmental change in expression of S-100 protein was determined in patients ranging in age from 34 gestational weeks to 57 years. In control patients the number of S-100 protein-immunoreactive cells increased during early infancy to reach a plateau; the number stayed at this level until adulthood and then gradually declined. In Down syndrome, the pattern was similar, except that the number of S-100 protein-positive cells in the hippocampus was greater than in controls, especially during early infancy and at older ages. In the patients examined in early infancy there was no evidence of astrogliosis. However, in older patients with Down syndrome the increased number of immunoreactive cells with antisera to both S-100 protein and glial fibrillary acidic protein indicates the presence of gliosis related to occurrence of senile plaques and neurofibrillary tangles. The increased immunoreactivity of S-100 protein in early life suggests that in trisomy 21 the expression of the gene for the beta subunit may be enhanced. The significance of increased S-100 protein in relation to neural maturation in Down syndrome is unknown.

Adolescent↗
PubMed1993

Delayed maturation of the vagus nerve in sudden infant death syndrome.

Abnormalities of the respiratory control system have been implicated in the cause of death in sudden infant death syndrome (SIDS). The vagus nerve is a major component of the neural regulation of respiration. Ultrastructural quantitative morphometry of myelinated and unmyelinated fibers was performed on cervical vagus nerves taken from 30 SIDS victims and 29 age-matched controls between 1 and 9 months of age. In SIDS infants, more small and fewer large myelinated vagal fibers were found than in controls, suggesting that the vagus nerve in SIDS is relatively immature. Delayed vagal nerve maturation, together with delays in central nervous system myelination and dendritic development, indicates a neural developmental delay in SIDS, the cause of which is undetermined.

Aging↗
PubMed1993

Peroxisomal disorders in children: immunohistochemistry and neuropathology.

Immunohistochemical studies with antisera against four peroxisomal enzymes, catalase and beta-oxidation enzymes (acyl-coenzyme A oxidase, bifunctional protein, and 3-ketoacyl-CoA thiolase), were performed on brain, liver, and kidney specimens from patients with peroxisomal disorders, as well as specimens from three control subjects, by using conventional paraffin-embedded autopsy material. The patients included eight with Zellweger syndrome and one with neonatal adrenoleukodystrophy. In the liver and kidney specimens from all patients, except one with Zellweger syndrome, diffuse immunostaining with all antisera in the cytoplasm of hepatocytes and renal tubular epithelium suggested an absence of peroxisomes but the presence of peroxisomal enzymes. Examination of brain specimens indicated a weak or negative reaction of neurons in the cerebral cortex and a weak reaction of glial cells in the white matter, which suggested maturational delay compared with control subjects. The delayed immunoreactive pattern of peroxisomal enzymes in Zellweger syndrome and neonatal adrenoleukodystrophy may be related to the significant neuropathologic features of polymicrogyria and dysmyelinogenesis. One patient with Zellweger syndrome had a unique finding of a positive granular catalase reaction and a negative reaction with antisera to 3-ketoacyl-coenzyme A thiolase, which suggested a diagnosis of pseudo-Zellweger syndrome. This study validates the application of these immunohistochemical methods to the study of peroxisomal enzymes. Use of these methods improves the accuracy of diagnosis of peroxisomal disorders.

Acetyl-CoA C-Acyltransferase↗
PubMed1993

Endophthalmitis caused by the coagulase-negative staphylococci. 2. Factors influencing presentation after cataract surgery.

PURPOSE: This study, comprising 60 patients with coagulase-negative staphylococcal endophthalmitis which occurred after cataract surgery, was designed to define the variation in disease presentation and visual outcome and to evaluate statistically the role of the primary surgery and its management. METHODS: An intensive evaluation of microbiological, inpatient, outpatient, and cataract surgery charts was made retrospectively using a standardized protocol. The predictive value of surgical, iatrogenic, and clinical factors was analyzed for their influence on defined aspects of the disease pattern and of the visual results using multiple regression models, via a stepwise technique. RESULTS: There was commonly a significant asymptomatic latent period after cataract surgery. The median diagnostic delay was 7 days; 22% of patients presented after 2 weeks and 12% after 1 month. Symptoms progressed longer than 3 days in 25% of patients. Ten percent had no pain. Clinical variation proved largely unrelated to cataract surgery events and postoperative management; bacterial factors were implicated. Good visual outcome was associated statistically with intensive topical corticosteroid in the symptomatic period, but was negatively associated with operative subconjunctival corticosteroid. CONCLUSIONS: The clinical variation in cases of postoperative coagulase-negative staphylococcal endophthalmitis poses particular problems for diagnosis in the outpatient setting. Surgical and perioperative events (except corticosteroid use) probably can be disregarded in studies of endophthalmitis management.

Adult↗
PubMed1993

Endophthalmitis caused by the coagulase-negative staphylococci. 1. Disease spectrum and outcome.

PURPOSE: The coagulase-negative staphylococci are the most common causes of postoperative endophthalmitis. This study investigates the variability in the disease spectrum and visual outcome of coagulase-negative staphylococcal endophthalmitis in a large, single-center series. METHODS: Ninety consecutive cases of coagulase-negative staphylococcal endophthalmitis were investigated retrospectively from two time periods, 1978 to 1982 and 1985 to 1987, separated by a transitional period in cataract surgery technique. Using a detailed protocol, inpatient, outpatient, and microbiologic records were analyzed. Six-month visual acuity results were obtained. RESULTS: Diagnosis frequently was delayed, often suspected only after hypopyon development. Thirty-seven percent of patients presented more than 1 week after the inoculating event, and 13% presented after more than 1 month. Variable asymptomatic intervals and gradually worsening inflammatory prodromes are noted. Painless endophthalmitis occurred in 16%. Non-epidermidis infections comprised 28%. With vitrectomy/intraocular antibiotic management, 38% and 68% achieved visual acuities of 20/50 and 20/400, respectively. Overall, 10% of patients developed late retinal detachments. This occurred in only 4% of patients, with endophthalmitis occurring after cataract surgery. CONCLUSION: Ophthalmologists should become familiar with the emerging concepts of delayed-onset, chronic, and often painless endophthalmitis in which the coagulase-negative staphylococci play a prominent role.

Adult↗
PubMed1993

Dystrophin expression in the human retina is required for normal function as defined by electroretinography.

We have studied retinal function by electroretinography in five Becker and six Duchenne muscular dystrophy patients. All had abnormal electroretinograms with a markedly reduced amplitude for the b-wave in the dark-adapted state. Using three antisera raised to different domains of dystrophin, we identified dystrophin in the outer plexiform layer of human retina. The retinal dystrophin is present in multiple isoforms as the result of alternative splicing. The localization of dystrophin to the outer plexiform layer coincident with the abnormal b-wave suggests that dystrophin is required for normal retinal electrophysiology.

Adolescent↗
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↗
PubMed1993

Clinicopathological study of pontosubicular necrosis.

Clinicopathological features were examined in 65 neonates and 8 stillborn infants with pontosubicular necrosis (PSN) compared to 57 neonates and 19 stillborn infants without PSN. Twelve out of 65 neonates with PSN had congenital heart disease and 3 out of 65 neonates showed persistent fetal circulation. On neuropathological examination, the frequency of neonates with PSN who also showed karyorrhetic/eosinophilic neurons in other regions of the brain stem, basal ganglia and thalamus was higher than in controls. The results of this study suggest that acute ischemia is an important underlying pathogenetic factor and PSN occurs in the prenatal as well as postnatal period.

Asphyxia Neonatorum↗
PubMed1993

Extensive malignant melanoma of the uvea in childhood: resection and immediate reconstruction with microsurgical and craniofacial techniques.

Malignant melanoma is a rare tumor in the pediatric age group. Those that have been reported generally describe cutaneous lesions. In children, malignant melanoma arising in the eye is exceedingly rare. The child we report was born with a uveal tract malignant melanoma with extensive extraocular invasion that was successfully managed with combined craniofacial and microsurgical techniques. This patient demonstrates the difficulty of making the correct diagnosis, the initial reluctance about surgical intervention in a newborn's condition, and the subsequent success possible with standard microsurgical and craniofacial techniques.

Facial Bones↗
PubMed1993

Familial desminopathy: myopathy with accumulation of desmin-type intermediate filaments.

Two siblings developed cardiomyopathy several years before slowly progressive muscle weakness. Skeletal muscle biopsy specimens showed subsarcolemmal crescents of dark eosinophilic material in both type I and type II fibres. Immunohistochemically the subsarcolemmal material stained positively for the intermediate filament protein desmin and for the heat shock protein ubiquitin but for no other cytoskeletal proteins. Ultrastructurally the subsarcolemmal deposits consisted of aggregates of granular and filamentous material arising from Z-bands. Follow up muscle biopsies six years later showed an increased number of the muscle fibres that contained subsarcolemmal aggregates that stained positively for desmin and ubiquitin. These clinical and pathological features characterise a rare familial myopathy associated with an unusual distribution of desmin intermediate filament proteins in skeletal and probably also cardiac muscle.

Child, Preschool↗
PubMed1993

Management and outcome of low-grade astrocytomas of the midline in children: a retrospective review.

Low-grade astrocytomas of the midline of the brain can be difficult to manage because of their location. To evaluate treatment and outcome, we performed a retrospective study of children with midline low-grade astrocytomas admitted to The Hospital for Sick Children between 1976 and 1991. Eighty-eight children with biopsy-proven low-grade astrocytomas were identified. Forty-three tumors occurred in the optic pathways or hypothalamus, 13 in the thalamus, 7 in the pineal region, 14 in the midbrain, and 11 in the medulla. Patient follow-up ranged from 6 months to 15 years, with a mean of 4 years, 9 months. Overall outcome was related to the extent of resection, histological type, and location. Partial resections were often associated with involution of the tumor. Response to radiation was variable, and serious sequelae were observed. Thirty-three patients experienced recurrence, often with a good response to subsequent surgery; however, 12 of these patients died. The probability of survival was calculated to be 96% at 1 year, 91% at 5, and 80% at 10 years. Our study suggests that resection should be considered in all patients, both at presentation and recurrence.

Adolescent↗
PubMed1993

Neuronal heterotopia with capillary penetration of neurons and cortical dysplasia in a patient with complex partial seizures. Case report.

Unusual pathological findings were encountered in a temporal lobectomy specimen from a 9-year-old boy with intractable complex partial seizures. Magnetic resonance imaging revealed an enlarged left temporal lobe, with diffuse high signal intensity over the cortex and poor gray-white differentiation on T2-weighted imaging; single-photon emission computerized tomography showed decreased blood flow. Active epileptiform discharges were identified in the left temporal lobe with focal slow waves and generalized epileptiform paroxysms. Pathologically, the cortex revealed changes of focal cortical dysplasia with extensive disorganization of neuronal morphology, layering, and orientation as well as focal polymicrogyria. The cortical-white matter junction was indistinct with extensive neuronal heterotopias in the white matter. Large pale balloon cells akin to those seen in tuberous sclerosis were found scattered within the cortex and white matter. The most striking finding was that of a heterotopic nodule in the white matter, which revealed abnormal neurons with penetration of cell bodies by capillaries. Ultrastructurally, there were no degenerative changes in these neurons, and this unusual phenomenon is attributed to a developmental disturbance affecting neuronal, glial, and vascular elements.

Brain Neoplasms↗
PubMed1993

Pathology of temporal lobectomy for refractory seizures in children. Review of 20 cases including some unique malformative lesions.

Significant pathological abnormalities were encountered in a series of 20 temporal lobectomies in children with intractable complex partial seizures. In particular, "dual pathology" (mesial temporal sclerosis with other lesions) was found rather than mesial temporal sclerosis as the only lesion. Unusual pathological findings included capillary penetration of neurons in a neuronal heterotopia in one patient, and foci of extensive cortical disorganization in some cases of mixed tumors and gangliogliomas. A high proportion of neuronal migration disorders was also seen with overlapping pathological features between cortical dysplasia and tuberous sclerosis. In this correlative clinical, radiological, electroencephalographic, and pathological study, some of the pathological lesions in children did not fit the classical categories of neoplasia and malformation and transitional forms were rarely encountered.

Adolescent↗
PubMed1993

Increased mitotic activity as a negative prognostic indicator in pleomorphic xanthoastrocytoma. Case report.

Pleomorphic xanthoastrocytoma is a recently characterized neoplasm with a favorable prognosis despite aggressive histological features. The authors report a case of pleomorphic xanthoastrocytoma that recurred 4 years after complete gross resection. The original tumor exhibited histological features characteristic of this neoplasm, but up to 4 mitoses/10 high-power fields were present focally. The recurrent tumor contained small foci of classical pleomorphic xanthoastrocytoma, but consisted predominantly of glioblastoma multiforme. Transitional zones contained nests of glial fibrillary acidic protein (GFAP)-immunopositive cells surrounded by delicate collagenous and reticulin-rich septa. Electron microscopy of the transitional zone showed continuous basal lamina investing cells containing bundles of intermediate filaments. These were GFAP-positive by immunogold electron microscopy, confirming the astrocytic nature of pleomorphic xanthoastrocytoma. This example illustrates the capacity of this tumor to evolve into glioblastoma. The indolent clinical behavior of most pleomorphic xanthoastrocytomas is evident from a literature review, which confirms the prolonged survival of many patients after onset of symptoms. Completeness of excision, subjectively assessed at surgery, did not influence the risk of recurrence or survival up to 10 years after initial resection. Postoperative radiotherapy did not improve survival, but may reduce the probability of recurrence; more studies are needed to corroborate this finding. The data compiled herein support the designation of pleomorphic xanthoastrocytoma as a distinct astrocytic neoplasm with a favorable prognosis. An increased mitotic rate has not previously been correlated with a worse outcome, and should not be used to exclude this diagnosis. However, anaplastic transformation of pleomorphic xanthoastrocytoma confers a much worse prognosis, and this case suggests that increased mitotic activity may be a negative prognostic indicator since it may herald subsequent anaplastic transformation.

Astrocytoma↗