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Biomedical subjects

L E Becker

Publications and source records attributed to L E Becker.

At least 235 records · Page 13Linked to original sources
PubMed1981

Abnormal neuronal development in the visual cortex of the human fetus and infant with down's syndrome. A quantitative and qualitative Golgi study.

The developmental morphology of visual cortical neurons (their numbers, dendritic arborization and numbers of spines) in 14 fetuses and infants with Down's syndrome were studied and compared with that of neurologically normal, age-matched controls. Fetuses with Trisomy 21 showed the same neuronal morphology and spine counts as control fetuses. However, the newborns and older infants with Down's syndrome showed shorter basilar dendrites and decreased numbers of spines with altered morphology and defective cortical layering.

Age Factors↗
PubMed1981

Abnormal electric membrane properties of Down's syndrome DRG neurons in cell culture.

Cell cultures were prepared from normal and Down's syndrome dorsal root ganglia (DRG). Both pre- and postnatal specimens were utilized; 8 normal and 4 Down's. Cultures were maintained in medium with normal (4 mM) and elevated (20 mM) potassium (K) since the latter was found to enhance neuron survival. After various period of incubation, cultures were transferred to normal K medium and their electrical membrane properties (EMP) determined using intracellular recording techniques. An analysis of variance was performed with 5 covariates: developmental stage, culture duration, K concentration, type of action potential, and neuronal surface area. This analysis indicated that the Down's neurons had abnormal EMP, the most affected being the after hyperpolarization (-41%), membrane time constant (+30%), threshold rheobasic depolarization (-22%), rate of falling phase of action potential (-20%), specific membrane resistance (+18%) and absolute refractory period (+12%). All differences were also observed when samples of normal and Down's neurons were matched for the 5 covariates mentioned above, take separately. If the abnormal EMP observed in the present study for Down's DRG neurons in culture occurred for CNS neurons in situ they would disrupt the normal function of the nervous system and could therefore constitute the neurobiological basis of the mental retardation observed in Down's syndrome.

Action Potentials↗
PubMed1981

Clinical progression of giant-axonal neuropathy over a twelve year period.

Giant-axonal neuropathy (GAN), a chronic peripheral neuropathy with associated Central Nervous System dysfunction and tight curly hair, is described in a 17-year-old girl. Biopsies of this girl's muscle and nerve are characteristic of this condition. Her clinical course over a 12 year period characterizes a disease of a slowly progressive nature.

Axons↗
PubMed1981

Topical clindamycin therapy for acne vulgaris. A cooperative clinical study.

Eleven institutions participated in an eight-week controlled clinical study to evaluate treatment of acne vulgaris with topical clindamycin hydrochloride and clindamycin phosphate. Three hundred fifty-eight patients with comparable baseline pustule, papule, and nodule counts applied 1%, clindamycin hydrochloride, 1% clindamycin phosphate, or a hydroalcoholic vehicle twice daily. Every two weeks, lesions were counted, and patients' evaluations of their acne conditions were scored. By week 8, pustule and papule counts in the groups who were receiving clindamycin were significantly lower than those in the group receiving placebo. Also, more patients who were receiving clindamycin thought their acne improved by week 8 (with significantly higher change-in-acne scores) than did the patients receiving placebo. Patients receiving clindamycin reported 12 episodes of diarrhea; only one episode was considered to be treatment related. These results substantiate the clinical impression that topical clindamycin is effective treatment for acne.

1-Propanol↗
PubMed1980

Morphology of the developing visual cortex of the human infant: a quantitative and qualitative Golgi study.

A renaissance of the Golgi impregnation method has focused interest on dendritic aspects of neuronal development. The visual cortices of 39 "neurologically normal" infants from 14 weeks' gestation to 6 months of age were prepared at postmortem for rapid Golgi impregnation studies. These were stained and duplicated with camera lucida drawings. The total number of cells in defined columns of the visual cortex was counted on cresyl violet-stained sections, and differentiated neurons were identified. The number of spines on the apical and basal dendrites of selected cells was counted for a given interval along the dendrites. The camera lucida drawings, cell counts, and spine counts were used to illustrate the normal ontogeny of the visual cortex.

Cell Count↗
PubMed1980

Neuropathology of cerebral arteriovenous malformations in children.

Neuropathological findings in children who had died of cerebral arteriovenous malformation under 6 years of age were contrasted with those of children aged 6 to 15 years. In all subjects, the abnormalities were more marked in the shunting vessels and veins distal to the arteriovenous shunt than in the arteries. Fibrous thickening, calcification an adherent thrombus of vessel wall, and gliosis and haemosiderin in contiguous neural tissue were more common in the older than the younger children. Children less than 1 week old with vein of Galen malformations presented with congestive heart failure and "watershed" cerebral infarction; most of those over one week old had hydrocephalus and venous thrombosis with haemorrhagic infarction.

Adolescent↗
PubMed1980

Correlation between computed tomography and autopsy in premature and full-term neonates that have suffered perinatal asphyxia.

The findings at autopsy were correlated with the computed tomographic (CT) diagnosis in 90 neonates that had suffered perinatal hypoxia and had CT within 10 days before autopsy. CT was accurate in the diagnosis of supratentorial hemorrhage whether it was subependymal, intraventricular, or intracerebral. Infratentorial hemorrhage was difficult to detect or localize with accuracy. Correlation between areas of hypodense brain tissue seen on CT and areas of ischemic brain damage other than hemorrhage at autopsy was poor. Diagnosis of generalized cerebral edema by CT, however, was very good.

Asphyxia Neonatorum↗
PubMed1980

Benzoyl peroxide lotion (20 percent) in acne.

A double-blind, controlled study was performed to determine the effectiveness of 20 percent benzoyl peroxide lotion in the mangement of mild to moderate acne vulgaris. The results of our study have shown that this new, higher concentration formulation of benzoyl peroxide is effective in reducing the lesions of acne and is relatively nonirritating.

Acne Vulgaris↗
PubMed1980

Basics of catheterization and catheter care.

There are scant audiovisual materials and few monographs relating to equipment, description, and usage in catheter technique and catheter care. Often residents, interns, nurses, and paraprofessionals have sketchy information about the practical aspects of the subject. This paper is intended to give such practical information.

Female↗
PubMed1980

Diminished immune response in sun-damaged skin.

In previously sensitized volunteers, higher concentrations of 2,4-dinitrochlorobenzene were necessary to elicit positive patch test reactions on the sun-damaged skin of the neck than on the protected skin of the upper part of the back. This difference was not found in subjects without evidence of sun damage, and there was no difference between sun-damaged and nondamaged skin in response to a primary irritant. Responses to intradermally injected common antigens were also less intense in sun-damaged skin that in nonexposed skin. These findings suggest the existence of a local defect in cell-mediated immunity in skin altered by long-term sun exposure.

Adolescent↗
PubMed1979

Electric membrane properties of human DRG neurons in cell culture and the effect of high K medium.

Cell cultures were prepared from human fetal and newborn dorsal root ganglia (DRG) and maintained in culture medium with normal (4 mM) and elevated (20 mM) potassium (K). Both types of cultures were transferred to 4 mM K, and the electrical membrane properties of the DRG neurons characterized by an extensive investigation of resting membrane potential, specific membrane resistance (Rm) and capacitance, time constant (tau), rheobasic current, and various aspects of the action potential, including overshoot, duration (DT), afterhyperpolarization and absolute refractory period (ARP). No previous quantitative determinations of these membrane properties for human neurons could be found. However, our values were in good agreement with those reported for the DRG neurons of other mammalian species both in vitro and in situ. Significant correlations occurred between membrane properties and the developmental age of each specimen used for culturing. However, the data must be interpreted cautiously due to the limited number of specimens used (4) and the possibility of differential responses of the specimens to the experimental situation. Precultivation in high K medium had profound effects on both passive and active membrane properties: the primary effect being to reduce Rm, and as a result tau, DT, and ARP were also reduced. These observations add further support to the hypothesis that high K in vitro can substitute to some extent for trophic factors normally present in situ.

Cells, Cultured↗
PubMed1979

An electron microscopic study of childhood dermatomyositis.

Muscle biopsies from 12 patients with a typical clinical picture of dermatomyositis have been examined by electron microscopy. Endothelial cells of intramuscular blood vessels, their basal lamina, pericytes, muscle fibers, and satellite cells show degenerative or regenerative alterations. In nine patients, tubular arrays were noted in the cisterns of endoplasmic reticulum of endothelial cells, pericytes, lymphocytes, macrophages and satellite cells. Other types of inclusions were also observed. The pathogenesis of the disease is discussed.

Adolescent↗
PubMed1979

Cell-mediated immunity in Darier's disease.

Darier's disease, often complicated by skin infections, has been linked with a depressed cell-mediated immunity. Four moderate to severely affected patients with a negative history of skin infections were studied. T cell function was evaluated by standard delayed hypersensitivity skin tests, enumeration of peripheral T cell-mediated immunity was found. The significance of the results when compared with prior studies is discussed.

Adolescent↗