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Biomedical subjects

C Billard

Publications and source records attributed to C Billard.

At least 19 recordsLinked to original sources
PubMed1999

[Benign infantile convulsions. French collaborative study].

BACKGROUND: Benign infantile non febrile seizures are not well known, leading us to study their clinical and EEG characteristics. METHODS: Between 1981 and 1994, we assembled 34 patients with the following inclusion criteria: non febrile seizures between 1 month and 2 years of age, normal personal history, no abnormality on clinical, biological and radiological investigations, normal developmental outcome with at least 1 year follow-up. RESULTS: These 34 patients were recognized as 14 familial cases (identical seizures affecting parents) and 11 non familial cases. The other nine cases had different or undefined epilepsy in the family. The clinical and EEG characteristics were the same: at the mean age of 6 months, brief partial seizures (often secondarily or apparently generalized) occurring in a cluster of two to 12 episodes a day for a mean duration of 2.5 days, with ictal EEG showing focal discharge, often slow waves or focal spikes on post-ictal tracing and normal interictal EEG. CONCLUSION: The clinical and EEG characteristics are important in order to recognize this type of infantile convulsions (familial or not familial), which have a good prognosis and need no aggressive treatment.

Age of Onset↗
PubMed1999

Recurrence of the T666M calcium channel CACNA1A gene mutation in familial hemiplegic migraine with progressive cerebellar ataxia.

Familial hemiplegic migraine (HM) is an autosomal dominant migraine with aura. In 20% of HM families, HM is associated with a mild permanent cerebellar ataxia (PCA). The CACNA1A gene encoding the alpha1A subunit of P/Q-type voltage-gated calcium channels is involved in 50% of unselected HM families and in all families with HM/PCA. Four CACNA1A missense mutations have been identified in HM: two in pure HM and two in HM/PCA. Different CACNA1A mutations have been identified in other autosomal dominant conditions: mutations leading to a truncated protein in episodic ataxia type 2 (EA2), small expansions of a CAG trinucleotide in spinocerebellar ataxia type 6 and also in three families with EA2 features, and, finally, a missense mutation in a single family suffering from episodic ataxia and severe progressive PCA. We screened 16 families and 3 nonfamilial case patients affected by HM/PCA for specific CACNA1A mutations and found nine families and one nonfamilial case with the same T666M mutation, one new mutation (D715E) in one family, and no CAG repeat expansion. Both T666M and D715E substitutions were absent in 12 probands belonging to pure HM families whose disease appears to be linked to CACNA1A. Finally, haplotyping with neighboring markers suggested that T666M arose through recurrent mutational events. These data could indicate that the PCA observed in 20% of HM families results from specific pathophysiologic mechanisms.

Calcium Channels↗
PubMed1998

Are Dp71 and Dp140 brain dystrophin isoforms related to cognitive impairment in Duchenne muscular dystrophy?

Molecular study and neuropsychological analysis were performed concurrently on 49 patients with Duchenne muscular dystrophy (DMD) in order to find a molecular explanation for the cognitive impairment observed in most DMD patients. Complete analysis of the dystrophin gene was performed to define the localization of deletions and duplications in relation to the different DMD promoters. Qualitative analysis of the Dp71 transcript and testing for the specific first exon of Dp140 were also carried out. Neuropsychological analysis assessed verbal and visuospatial intelligence, verbal memory, and reading skills. Comparison of molecular and psychometric findings demonstrated that deletions and duplications that were localized in the distal part of the gene seemed to be preferentially associated with cognitive impairment. Two altered Dp71 transcripts and two deleted Dp140 DNA sequences were found in four patients with severe cerebral dysfunction. These findings suggest that some sequences located in the distal part of the gene and, in particular, some DMD isoforms expressed in the brain may be related to the cognitive impairment associated with DMD.

Adolescent↗
PubMed1998

Reading ability and processing in Duchenne muscular dystrophy and spinal muscular atrophy.

We analysed the reading abilities and processing of 21 children with Duchenne muscular dystrophy (DMD), 11 matched children suffering from spinal muscular atrophy (SMA) and 42 children receiving normal education. The principal result observed was that the DMD children exhibited a reading age which was significantly lower than the SMA children compared with their chronological age. These learning disabilities were not related to a deficit in non-verbal performance intelligence, but psycholinguistic evaluation showed a deficit in verbal intelligence, especially in the Similarities and Arithmetic WISC-R subtests, in phonological abilities, oral word repetition, and in digit span score. The results for the DMD children were heterogeneous, and ranged from normal to greater or lesser involvement. In an attempt to clarify the nature of this reading impairment in DMD children, the three groups (DMD, SMA, and normal control children) were tested by reading aloud a list of single words and non-words. The DMD children were significantly impaired in reading non-words, suggesting reading disability similar to dysphonetic dyslexia, the most frequent subtype of developmental dyslexia. These results are discussed in the light of psychometric data available for our DMD population and in the light of previous studies. The practical consequences of diagnosis on rehabilitation are very important. The precise description of the cognitive deficits seen in DMD is of value for future clinical and genetic studies.

Adolescent↗
PubMed1998

[An example of how to measure the relation between developmental dyslexia and illiteracy].

The ability to read and the phonological fitness of 89 youth (average age of 21.3 years) having difficulty with social and professional integration were examined. We observed that 64% of them (n = 57) had difficulty in reading. The results of the phonological and reading tests showed that developmental dyslexia constitutes, for 56% of the subjects (n = 32), or for 36% of the population of youth with difficulties, the explanatory framework for the delay of acquisition of these capacities. Reading difficulties for these youth were significantly linked to an alteration of the phonological treatment that effects: short-term verbal memory, auditory discrimination and meta-phonological fitness. The data tends to validate the hypothesis of the existence of a functional link between developmental dyslexia and illiteracy.

Adolescent↗
PubMed1998

[Corpus callosum syndrome in children].

The survey of callosotomized children is a difficult because they often present a severe epilepsy with mental retardation. The younger the child, the better he recovers. The child can be considered as a physiological split-brain. If one compares commissurotomized children with those presenting an agenesis of the corpus callosum, the later ones have, to a certain extent, an interhemispherical transfer which suggests supportive ipsilateral or sub-cortical connections.

Agenesis of Corpus Callosum↗
PubMed1997

Interleukin-13 responsiveness and interleukin-13 receptor expression in non-Hodgkin's lymphoma and reactive lymph node B cells. Modulation by CD40 activation.

Interleukin-13 (IL-13) responsiveness was examined in lymph node B cells from patients with non-Hodgkin's lymphoma (NHL) and patients with benign reactive immune disorders. Proliferation assays showed that NHL B cells from 8 of 21 patients responded to IL-13 in the absence of a co-activation signal. IL-13-unresponsive NHL B cells from 9 of the 13 remaining patients were induced to respond to IL-13 upon antibody-triggered CD40 activation, as did reactive B cells. Binding experiments with radiolabeled IL-13 revealed that the constitutive expression of IL-13 receptors (IL-13R) was associated with IL-13 responsiveness in the absence of CD40 activation. In IL-13-unresponsive cells, IL-13R expression was induced after CD40 activation. This effect was enhanced by IL-10, which was able to potentiate the IL-13 response of CD40-activated cells. Furthermore, IL-13 was found to increase the viability of cultured NHL cells, but not that of non-malignant cells. These results suggest that IL-13, which behaves as a potent co-factor for normal lymph node B cell activation, might provide growth and/or survival advantages to NHL B cells.

B-Lymphocytes↗
PubMed1996

Sterol composition of phaeodactylum tricornutum as influenced by growth temperature and light spectral quality.

In a detailed sterol analysis of the marine diatom Phaeodactylum tricornutum, free sterols as well as esterified and glycosylated conjugates were found. When the alga was grown under standard conditions (i.e., at 13 degrees C under white light), 64% of total sterols were steryl glycosides. In all sterol classes, except steryl esters, (24S)-24-methylcholesta-5,22E-dien-3 beta-ol (epibrassicasterol) was the major (80 to 99%) sterol component. Eight other sterols were identified. Growth under different light spectral quality (red, blue, yellow, and green) at 13 and 23 degrees C was examined. At 23 degrees C, a dramatic decrease in total sterol content was observed, especially under blue light. The distribution of sterols between free and conjugated forms as well as sterol profile inside each class was found to be strongly dependent on the light spectral quality at both temperatures.

Eukaryota↗
PubMed1996

[Developmental dysphasia].

Developmental dysphasia is characterized by severe, specific and unexplained developmental language impairment. Phonologic and syntactic disorders of expressive language and perceptual deficit are almost always present. Moreover, certain specific linguistic symptoms are particular to each dysphasic child, explaining the efforts to classify different forms of dysphasia. The most important point is to separate receptive dysphasia from the expressive on the one hand, and severe forms from the mild which are closed to "simple language delay", on the other. The evolution of oral language is variable, but often long and difficult, with persistent linguistic deficit. Reading and writing acquisition is usually difficult, although very important for the socio-professional outcome and language improvement. The etiology remains unknown and is probably multifactorial. One pathogenic hypothesis is based on the absence of the usual hemisphere specialisation related to various prenatal or postnatal events. A genetic basis seems likely for certain dysphasic children. Development of knowledge about this condition and improvement of both speech therapy and teaching are essential for the outcome of these otherwise intelligent and normal children.

Aphasia↗
PubMed1995

Study of unilateral hemisphere performance in children with developmental dysphasia.

Hemisphere specialization for language was studied in 10 children with expressive developmental dysphasia (DD) (mean age 10 years 4 months) submitted to a dichotic listening task (in a word free-recall task and forced-attention task) and a finger tapping/vocalization dual-task paradigm. A nonsense shape dichaptic task was also introduced to control right hemispheric processing. Performances of dysphasic children were compared to those obtained from 15 normal children. The results showed that controls had a right ear advantage in free-recall (words) dichotic listening task and a significant right ear advantage in forced-right-attention task, with a change in ear asymmetry as a consequence of instruction. In the dysphasic group we observed a significant right ear advantage in the free-recall dichotic listening task and no change in ear asymmetry during forced right or forced left condition. Results in time sharing paradigm and nonsense dichaptic task are more difficult to interpret, because there was no interaction between group and condition. These results cannot support a complete left hemisphere dysfunction in developmental dysphasia.

Aphasia↗
PubMed1995

Sleep EEG and developmental dysphasia: lack of a consistent relationship with paroxysmal EEG activity during sleep.

In order to clarify the relationship between developmental dysphasia and EEG abnormalities, paroxysmal activities during sleep were studied in a series of 24 children with expressive developmental dysphasia (mean age 8 years) and compared to a control group of 39 children (mean age 9 years). The children of both groups were selected excluding cases with prior history of neurological disease or epilepsy. In the control group, 37 children had normal sleep EEG while 2 children had paroxysmal abnormalities. In the dysphasic group, epileptic abnormalities were observed in 9 cases, rare in 4 cases and frequent in 5 cases (density: 2.5 to 66.2% of total sleep time). Nevertheless, paroxysmal abnormalities did not reach the frequency described in the Landau-Kleffner syndrome, and it is unlikely that EEG abnormalities could have produced dysphasia.

Aphasia↗
PubMed1995

Relapse of herpes simplex encephalitis.

We report five children who had recurrent central nervous system signs after conventional acyclovir therapy for herpes simplex encephalitis. Secondary exacerbation was characterized clinically by severe ballismic movement disorder in all five children, associated with fever, impairment of consciousness, and seizures. Biologic analysis in all children and magnetic resonance imaging and neuropathology studies of the brain in three cases were compatible with inflammatory reaction. In contrast, all viral cultures remained negative, herpes simplex virus antigen in one child and DNA tested by polymerase chain reaction in four children were undetectable in the first samples of cerebrospinal fluid during the relapse, suggesting a postinfectious, immune-mediated mechanism of relapse in these patients.

Acyclovir↗
PubMed1995

Autocrine loop of tumor necrosis factor induced by interferon-alpha in tumor cells from hairy cell leukemia.

Interferon-alpha (IFN-alpha) is successfully used in the therapy of hairy cell leukemia (HCL). We previously reported that IFN-alpha administered to HCL patients stimulated the levels of tumor necrosis factor (TNF) receptors on hairy cells. Here, we investigated the interactions between IFN-alpha and TNF, using the HCL cell line Eskol as a model. We showed that increased levels of TNF receptors (TNFR) induced by IFN-alpha treatment were associated with stimulation of high M(r) TNFR. Low M(r) TNFR were not detected on Eskol cells or hairy cells, either before or after IFN-alpha treatment. Furthermore, the expression of TNF mRNA increased in Eskol cells treated with IFN-alpha for 1-4 h as compared to control cells. In vivo experiments showed that IFN-alpha given to HCL patients induced both TNF mRNA expression in hairy cells and secretion of active TNF protein in patients' serum. These results provide evidence that IFN-alpha may induce an autocrine loop of TNF in HCL.

Humans↗
PubMed1994

Differential regulation of interleukin-6 receptors by interleukin-6 and interferons in multiple myeloma cell lines.

Interleukin-6 (IL-6) mediates pleiotropic functions through specific receptors (IL-6R) composed of an 80-kDa binding protein, associated with a non-ligand binding protein (gp130) which transduces the signal. Because IL-6 is the major tumor growth factor in multiple myeloma, we investigated the regulation of IL-6R in two human multiple myeloma cell lines. Binding experiments with 125I-labeled IL-6 showed that IL-6R were expressed at a high density on RPMI-8226 cells (15 000 receptors/cell), but no specific binding was detected on XG-1 cells, whose growth depends on the presence of exogenous IL-6. However, when IL-6 was removed from the culture medium, high-affinity IL-6R appeared on the surface of XG-1 cells (5300 sites/cell). Treatment of RPMI-8226 cells with IL-6 reduced the number of IL-6R without changing their affinity. This reduction was dose dependent and was not affected by acid treatment which dissociates ligand-receptor complexes. Cross-linking experiments showed that the formation of one IL-6/receptor complex of 160 kDa markedly decreased upon IL-6 treatment, while the other complex of 190 kDa became undetectable. These data provide evidence for ligand-induced down-regulation of membrane IL-6R expression in myeloma cells. Treatment of RPMI-8226 cells with interferon-alpha (IFN-alpha), which inhibits the growth of these cells, stimulated IL-6R expression and increased the formation of the 160-kDa IL-6/receptor complex. This stimulation was specific for IFN-alpha, since IFN-gamma reduced the number of IL-6R. These data indicate that, in myeloma cells, IL-6R are differentially regulated by IL-6 and IFN-alpha.

Binding, Competitive↗
PubMed1994

Genetic basis of developmental dysphasia. Report of eleven familial cases in six families.

The genetic basis of Developmental Dysphasia is discussed with precise neuropsychological descriptions of 11 cases in six families. In these cases the coexistence in the same family of completely normal and severely impaired siblings suggests a genetic rather than a familial socio-linguistic cause. The possibility of father-son transmission eliminates X-linked inheritance. The results are discussed with a reappraisal of the literature and seem to emphasize the genetic basis, possibly, with autosomal dominant transmission in some cases of Developmental Dysphasia.

Adolescent↗
PubMed1993

[Interferons, a class of cytokines with a large therapeutic activity range].

Initially discovered as antiviral agents, the interferons (IFNs) proved to be a class of cytokines with multifunctional properties, including inhibition of cell growth and modulation of immune functions. A number of clinical trials were thus carried out in cancer and viral diseases, and IFN-alpha therapy was shown to have a wide range of indications in hematology and dermatology: B-cell malignancies (hairy cell leukemia, non-Hodgkin's lymphoma, multiple myeloma), myeloproliferations (chronic myeloid leukemia, thrombocytosis), cutaneous T lymphoma, basal-cell carcinoma, cutaneous squamous cell carcinoma, Kaposi's sarcoma. IFN therapy also showed efficacy in viral tumors (condyloma acuminatum and laryngeal papillomatosis) and chronic hepatitis B and C. The antitumoral action of IFN-alpha mainly involves its capacity to inhibit cell proliferation, partly via antagonistic effects on growth factors. The elucidation of IFN-alpha signalling pathway(s) leading to gene activation, a better understanding of the interactions between IFN-alpha and cytokine network, and the development of combination therapy with other biological treatments or chemotherapy should greatly improve the clinical use of IFNs.

Cell Differentiation↗