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L S Dure

Publications and source records attributed to L S Dure.

At least 19 recordsLinked to original sources
PubMed2006

Early progressive encephalopathy in boys and MECP2 mutations.

MECP2 mutations mainly occur in females with Rett syndrome. Mutations have been described in 11 boys with progressive encephalopathy: seven of nine with affected sisters and two de novo. The authors report four de novo occurrences: three pathogenic and one potentially pathogenic. Common features include failure to thrive, respiratory insufficiency, microcephaly, and abnormal motor control. MECP2 mutations should be assessed in boys with progressive encephalopathy and one or more of respiratory insufficiency, abnormal movements or tone, and intractable seizures.

Cerebral Cortex↗
PubMed2005

Atomoxetine treatment in children and adolescents with ADHD and comorbid tic disorders.

OBJECTIVE: To test the hypothesis that atomoxetine does not significantly worsen tic severity relative to placebo in children and adolescents with attention deficit/hyperactivity disorder (ADHD) and comorbid tic disorders. METHODS: Study subjects were 7 to 17 years old, met Diagnostic and Statistical Manual of Mental Disorders-IV criteria for ADHD, and had concurrent Tourette syndrome or chronic motor tic disorder. Patients were randomly assigned to double-blind treatment with placebo (n = 72) or atomoxetine (0.5 to 1.5 mg/kg/day, n = 76) for up to 18 weeks. RESULTS: Atomoxetine treatment was associated with greater reduction of tic severity at endpoint relative to placebo, approaching significance on the Yale Global Tic Severity Scale total score (-5.5 +/- 6.9 vs -3.0 +/- 8.7, p = 0.063) and Tic Symptom Self-Report total score (-4.7 +/- 6.5 vs -2.9 +/- 5.2, p = 0.095) and achieving significance on the Clinical Global Impressions (CGI) tic/neurologic severity scale score (-0.7 +/- 1.2 vs -0.1 +/- 1.0, p = 0.002). Atomoxetine patients also showed greater improvement on the ADHD Rating Scale total score (-10.9 +/- 10.9 vs -4.9 +/- 10.3, p < 0.001) and CGI severity of ADHD/psychiatric symptoms scale score (-0.8 +/- 1.1 vs -0.3 +/- 1.0, p = 0.015). Discontinuation rates were not significantly different between treatment groups. Atomoxetine patients had greater increases in heart rate and decreases of body weight, and rates of treatment-emergent decreased appetite and nausea were higher. No other clinically relevant treatment differences were seen in any other vital sign, adverse event, or electrocardiographic or laboratory measures. CONCLUSIONS: Atomoxetine did not exacerbate tic symptoms. Rather, there was some evidence of reduction in tic severity with a significant reduction of attention deficit/hyperactivity disorder symptoms. Atomoxetine treatment appeared safe and well tolerated.

Adolescent↗
PubMed2002

Clinical and genetic heterogeneity in benign hereditary chorea.

BACKGROUND: Benign hereditary chorea (BHC) is an autosomal dominant disorder that can be distinguished from Huntington disease by its early onset, stable or only slightly progressive course, and absence of mental deterioration. The variation in clinical features is such that its very existence has been doubted. The authors recently described the localization of a gene responsible for BHC on chromosome 14q in a large Dutch family. OBJECTIVE: To report results of extensive clinical and linkage analyses for this Dutch family and six other families with BHC. RESULTS: Three of the seven families had linkage to a region on chromosome 14q13.1-q21.1. HOMOG analysis showed odds of 10 x 10(11) in favor of locus heterogeneity. Haplotype analyses for the linked families resulted in a reduction of the critical interval for the BHC gene to 8.4 cM between marker D14S49 and marker D14S278. Clinically, these three families had a homogeneous picture with early-onset chorea, sometimes accompanied by slight ataxia in walking, but without dystonia, myoclonic jerks, or dysarthria. The severity of the choreatic movements tended to abate in adolescence or early adulthood. In the unlinked families, symptoms and signs were more heterogeneous as to age at onset and the occurrence of myoclonic jerks or dystonia. CONCLUSIONS: BHC is a clinically and genetically heterogeneous disorder, with one well-defined clinical syndrome mapping to chromosome 14q.

Adolescent↗
PubMed2001

Essential tremor in childhood: a series of nineteen cases.

One in 20 essential tremor (ET) cases arises during childhood. We report 19 pediatric ET cases (mean age = 12.7 years). The majority (68.4%) were male, and only one had head tremor. Childhood and adult forms of ET may differ in several important respects, providing information about the underlying biology of ET. A possible male preponderance in childhood ET cases could reflect a modification of disease expression by gender, such that males manifest the disease at an earlier age than females. A paucity of childhood cases with head tremor suggests that the neuropathological changes in ET may evolve somatotopically. Head tremor may require midline or more extensive bilateral pathology which may only occur later in the disease.

Adolescent↗
PubMed2001

Medial medullary injury during adenoidectomy.

We report medullary injury during adenoidectomy in two children who received injections of local anesthetic agents into the operative bed. Initial manifestations included hemiparesis, nystagmus, and ataxia. Magnetic resonance imaging showed hemorrhagic, paramedian medullary lesions in both patients. The mechanism of injury is likely to be injection of fluid into the medulla.

Adenoidectomy↗
PubMed2000

Mammal-like striatal functions in Anolis. II. Distribution of dopamine D(1) and D(2) receptors, and a laminar pattern of basal ganglia sub-systems.

We used in situ autoradiographic ligand binding methods to determine the occurrence and distribution of dopamine D(1) and D(2) receptor sub-types in the anole lizard, Anolis carolinensis. Both were present and exhibited pharmacological specificity characteristics similar to those described for mammals. However, unlike in mammals where in the neostriatum [outside the nucleus accumbens/olfactory tubercle complex (NA/OT)] these receptors exhibit only slight dorsolateral (D(2) high, D(1) low) to ventromedial (D(1 )high, D(2) low) gradients that co mingle extensively, in the anole striatum outside the NA/OT there was a striking laminar pattern, with little if any overlap between D(2) (high in a dorsal band) and D(1) (high ventral to the D(2) band) distributions. As D(1) receptors are related to the direct and D(2) to the indirect basal ganglia (BG) subsystems in mammals, we also determined anole striatal distributions of pre-proenkephalin mRNA, a marker for striatal efferents to the indirect BG subsystem in mammals. Here, too, there was a striking laminar pattern, with pre-proenkephalin mRNA in a band similar to that seen for D(2) receptors. The crisp neuroanatomical separation between these classic BG subsystem markers in Anolis striatum make this species attractive for the study of such systems' functions during behavior.

Animals↗
PubMed1998

Neonatal encephalopathy in two boys in families with recurrent Rett syndrome.

Rett syndrome (RTT) has been described in its classic form only in females. Although the majority of cases are sporadic, familial cases give valuable insight into the genetic basis and phenotypic variability of the disorder. The exclusive occurrence of classic Rett syndrome in females led to the hypothesis that the Rett syndrome locus is likely to be X-linked and mutations are lethal in hemizygous males. We identified two boys in families with recurrent Rett syndrome who had encephalopathies with neonatal onset and who may represent the phenotype of males harboring Rett syndrome mutations. The difference in severity of disease in these males and their female relatives supports the location of Rett syndrome locus on the X-chromosome.

Brain Diseases↗
PubMed1997

Ectopically expressed CAG repeats cause intranuclear inclusions and a progressive late onset neurological phenotype in the mouse.

The mutations responsible for several human neurodegenerative disorders are expansions of translated CAG repeats beyond a normal size range. To address the role of repeat context, we have introduced a 146-unit CAG repeat into the mouse hypoxanthine phosphoribosyltransferase gene (Hprt). Mutant mice express a form of the HPRT protein that contains a long polyglutamine repeat. These mice develop a phenotype similar to the human translated CAG repeat disorders. Repeat containing mice show a late onset neurological phenotype that progresses to premature death. Neuronal intranuclear inclusions are present in affected mice. Our results show that CAG repeats do not need to be located within one of the classic repeat disorder genes to have a neurotoxic effect.

Animals↗
PubMed1997

Is cell death necessary for hippocampal mossy fiber sprouting?

To examine the relationship between cell death and sprouting of the mossy fibers, repeated seizures of the hippocampal-parahippocampal circuit were elicited in anesthetized rats. The presence of mossy fiber growth was assessed with the Timm's stain for zinc. At 4 weeks, after 18 repeated seizures, there was a significant increase in the degree of zinc containing granules in the inner molecular layer of the dentate gyrus. The amount of sprouting was less than that seen four weeks after a single injection of kainic acid. A silver impregnation stain and an assay for damaged DNA were used to detect damaged or dying neurons and immunohistochemistry for a 72 kDa heat shock protein was used to detect any neurons that had suffered potentially injurious stress. The same number of repeated seizures that caused sprouting of the mossy fibers did not cause detectable cell death or severe stress in any cells within the hippocampus, subicular region or adjacent entorhinal cortex. These experiments demonstrate that repeated seizures of the hippocampal-parahippocampal circuits can cause sprouting of mossy fibers in the absence of evidence of cell death. This supports the hypothesis that alterations in intrinsic neural excitability and impulse activity from the dentate gyrus can result in growth of axonal processes in the adult rat brain.

Animals↗
PubMed1997

Tourette syndrome.

This survey of recent literature addressing Tourette syndrome reflects clinical and laboratory findings of investigations of behavioral, neuropsychological, imaging, genetic, neurobiological and treatment considerations. Tourette syndrome is a prototypic neuropsychiatric disorder manifesting a full range of objectively describable phenomena from different scientific vantage points and serves as a model for study and integrative understanding of brain and behavior.

Adolescent↗
PubMed1995

Huntington's disease gene: regional and cellular expression in brain of normal and affected individuals.

Huntington's disease (HD) is an autosomal dominant disorder characterized by involuntary movements, dementia, and progressive, global, but regionally accentuated, brain atrophy. The disease affects the striatum most severely. An expansion of a trinucleotide repeat on chromosome 4p16.3 within the coding region of a gene termed IT15 has been identified as the mutation causing HD. The normal function of IT15 and the mechanisms by which the presence of the mutation causes HD are unknown. Although IT15 expression has been detected in the brain, as well as in other organ tissues, by Northern blot and in situ hybridization, it is not known whether a preferential regional or cellular expression of IT15 exists within the central nervous system of normal, affected, and presymptomatic individuals. Using quantitative in situ hybridization methods, we examined extensively the regional and cellular expression of IT15. In controls, IT15 expression was observed in all brain regions examined with the highest levels seen in cerebellum, hippocampus, cerebral cortex, substantia nigra pars compacta, and pontine nuclei. Expression in the striatum was intermediate and expression in the globus pallidus was low. IT15 was expressed predominantly in neurons; a low but significant level of expression was seen in glial cells. Analysis of grain counts per square micrometer in neurons showed that the regional differences in the level of mRNA expression were related to density and size of neurons in a given region and not primarily to differences in levels of mRNA expression in individual cells after correction for cell size. Neurons susceptible to degeneration in HD did not selectively express high levels of IT15 mRNA. In HD brains (grades 2-4), the distribution and levels of IT15 mRNA were comparable with controls in all areas except in neostriatum where the intensity of labeling was significantly reduced. Presymptomatic HD brains had a striatal expression similar to controls and surviving striatal neurons in more advanced HD had an expression of IT15 within normal limits. It is apparent from these results that the presence of expanded trinucleotide repeats in HD does not result in the absence of IT15 mRNA expression or in altered patterns or levels of expression. The lack of correlation between the levels of IT15 mRNA expression and susceptibility to degeneration in HD strongly suggests that the mutant gene acts in concert with other factors to cause the distinctive pattern of neurodegeneration in HD.

Aged↗
PubMed1995

DNA fragmentation and immediate early gene expression in rat striatum following quinolinic acid administration.

Excitotoxic cell death is hypothesized to contribute to numerous neuropathologic conditions, including hypoxic/ischemic encephalopathy, hypoglycemia, Parkinson's disease, and Huntington's disease. Neuronal death from excitotoxic lesions has been shown to be an active process, with activation of immediate early gene transcription, resulting in secondary changes in gene expression. Another feature of neurotoxic cell death that has been examined is the presence of DNA fragmentation, which presumably indicates impending nuclear disintegration. A technique has been described for labeling fragmented DNA in situ, allowing precise determination of the anatomic and temporal distribution of neurons after an excitotoxic lesion. To investigate this phenomenon, we performed in situ nick translation on brain tissue from rats that have undergone stereotaxically placed intrastriatal quinolinic acid injections. Furthermore, in these same animals we analyzed the expression of c-fos mRNA to compare the time course and regional distribution of DNA fragmentation with immediate early gene activation after an excitotoxic lesion. Our analysis indicates that c-fos expression increases soon after quinolinic acid injection, is widespread in rat brain, but is effectively absent by 24 h postinjection. DNA fragmentation, however, is limited to striatum and is maximal at 24 h after injection. These results demonstrate the sensitivity of in situ nick translation for the detection of regional neuropathology and illustrate the temporal and spatial relationship of c-fos expression to excitotoxic neuronal death.

Animals↗
PubMed1994

IT15 gene expression in fetal human brain.

To examine the expression of the gene which causes Huntington's disease (HD), IT15, during development, in situ hybridization of radiolabeled riboprobes was performed in human fetal (gestational ages 20-23 weeks) and adult brain. Optical densities of autoradiographs were determined in various brain regions and compared to cell density in those regions. IT15 expression was found in all regions of the fetal and adult brain, and there was a high degree of correlation of autoradiographic signal with cell number in all regions but germinal matrix in fetal brain and white matter in adult brain. These two regions are notable for their significant proportion of glial cells, and suggest that IT15 expression is predominantly neuronal. There was no preponderance of IT15 expression in striatal compartments in fetal brain as demonstrated by acetylcholinesterase activity, nor was there differential expression of IT15 in brain regions known to be particularly affected in HD. IT15 gene expression is present by 20 weeks gestation in human brain, and at that stage of development exhibits a pattern of distribution which is similar to adult brain. If a developmentally-regulated role for IT15 exists in the pathogenesis of HD, it must occur prior to 20 weeks gestation.

Aged↗
PubMed1994

Trinucleotide repeats in neurologic diseases: an hypothesis concerning the pathogenesis of Huntington's disease, Kennedy's disease, and spinocerebellar ataxia type I.

Three neurodegenerative diseases, Huntington's disease (HD), Kennedy's disease (hereditary spinobulbar muscular atrophy, SBMA), and type 1 spinocerebellar ataxia (SCA-1) have been found to share a common genetic defect: an unstable region of repeated CAG trinucleotides which are thought to be translated into a polyglutamine moiety. The unstable repeat regions occur near the N-termini of the predicted proteins for HD and SBMA, but the location of the CAG repeat region is not known for SCA-1. Each disease is notable for a relatively circumscribed region of central nervous system pathology, and the lack of predicted similarity of the abnormal proteins makes a common mechanism related to the function of each protein unlikely. In order to reconcile the similar genetic abnormalities with the disparities in phenotypes, we suggest a common thread with regard to the pathogenesis of neuronal death. We hypothesize that the mechanism of neurotoxicity in these diseases occurs not through the production of abnormal proteins, but by the generation of abnormal posttranslational cleavage products. These products, in part consisting of abnormally large polyglutamine moieties, act to disturb the cellular and mitochondrial milieu such that energy metabolism is impaired, rendering specific regions of the nervous system vulnerable, and resulting in the clinical phenotypes of HD, SBMA, and SCA-1. We offer this interpretation of recent genetic findings from a neurobiologic perspective, in addition to suggesting testable hypotheses concerning potential disease mechanisms.

Base Sequence↗
PubMed1992

Compartmentalization of excitatory amino acid receptors in human striatum.

Division of the mammalian neostriatum into two intermingled compartments called striosomes and matrix has been established by analysis of enzyme activity, neuropeptide distribution, nucleic acid hybridization, and neurotransmitter receptor binding. Striosomes and matrix are distinct with respect to afferent and efferent connections, and these regions provide the potential for modulation and integration of information flow within basal ganglia circuitry. The primary neurotransmitters of corticostriatal afferents are excitatory amino acids, but to date no correlation of excitatory amino acid receptors and striatal compartments has been described. We examined binding to the three pharmacologically distinct ionotropic excitatory amino acid receptors, N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid, and kainate, in human striatum using in vitro receptor autoradiography and compared the binding to striosomes and matrix histochemically defined by acetylcholinesterase activity. Our findings reveal increased binding to N-methyl-D-aspartate receptors and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors in matrix relative to striosomes and increased kainate receptor binding in striosomes relative to matrix. These results suggest that afferent input to the two striatal compartments may be mediated by pharmacologically distinct excitatory amino acid receptor subtypes.

Acetylcholinesterase↗