Dynamics in incommensurate phases studied by NMR: Theory and relaxation measurements on 87Rb satellites in Rb2ZnCl4.
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Journal Article↗
Biomedical subjects
D Michel
Publications and source records attributed to D Michel.
Human herpesvirus 6 DNA in exanthematous skin in BMT patient.
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Bone Marrow Transplantation↗
Induction of apoptosis in mouse [correction of rat] olfactory neuroepithelium by synaptic target ablation.
The olfactory system provides a useful in vivo model for studying the influence of synaptic targets on the survival of relay neurones. The bipolar sensory neurones located in the olfactory mucosa project synaptically onto the ipsilateral olfactory bulb, and their survival depends on the integrity of this connection. We demonstrate here that the retrograde neuronal degeneration induced by olfactory bulb removal involves apoptosis. As revealed by typical nucleosome-sized fragmentations of the genomic DNA, the apoptosis rate reaches a maximum 32 h after bulbectomy. A transient c-fos mRNA accumulation was detected, peaking 16 h after bulbectomy, suggesting that c-fos is involved in the early steps of programmed cell death.
Animals↗
An unstable allele at the maize Opaque2 locus is caused by the insertion of a double Ac element.
An unstable allele designated o2-m55, was isolated as a derivative of the o2-m5 allele. Whereas the o2-m5 allele is caused by the insertion of one copy of the transposable element Activator (Ac) into the first exon of the maize Opaque2(O2) gene, the o2-m55 allele contains two Ac elements. The position of one copy is identical to the position of the Ac element in the o2-m5 allele. The second copy is present within the first copy, thereby interrupting its structure shortly before the first ATG of the major reading frame of Ac. Both Ac sequences have the same orientation. Excision of the internal Ac element as well as excision of the complete double Ac element was detectable. Truncated double Ac elements comprising the complete internal Ac element and either the proximal or distal fragment of the interrupted Ac element can also be excised. The Ac elements exhibit a strong negative dosage effect: kernels which display revertant sectors in a mutant background are rarely seen in plants homozygous for the o2-m55 allele. If only one dose of the o2-m55 allele is present in endosperm tissue, revertant sectors can be detected. The amount of the transcript expressed from the internal Ac element of the o2-m55 allele is less than that derived from the single Ac element present in the o2-m5 allele.
Alleles↗
[Aneurysms of the intra-atrial septum complicated by cerebral ischemia in young subjects. 4 cases].
Transoesophageal echocardiography has improved the detection of potential sources of cerebral embolism. We report our experience with a group of 38 patients under 45 years of age who were examined after an arterial ischaemic cerebral event. We observed 4 patients (2 males, 2 females; age 17, 24, 38 and 40 years) with an atrial septal aneurysm. Cerebral ischaemia was permanent in 3 patients and temporary in 1 and a cerebral embolism was the most probable cause based on angiographic findings. The atrial septal aneurysm was only diagnosed by transoesophageal echocardiography (type IA in case 3, IB in the others). A patent foramen ovale was observed in 3 and this abnormality, which is known to have a high prevalence in the general population, could at most be an aggravating factor. In our series, we can assume a causal association between atrial septal aneurysm and stroke in young patients (10.5% among 38 young stroke patients vs 3% of 30 patients referred for other reasons). The treatment is still under discussion although the consensus would favour surgery if another heart malformation is associated, if a visible thrombus is identified or if repeated cerebrovascular events occur despite adequate anticoagulation. Studies conducted in large series of patients should provide more adequate therapeutic schemas.
4-Hydroxycoumarins↗
Structure and regulation of an ABA- and desiccation-responsive gene from the resurrection plant Craterostigma plantagineum.
A gene from the resurrection plant Craterostigma plantagineum (CDeT6-19) encoding a protein with sequence similarity to a major group of late embryogenesis-abundant proteins (termed rab17, dehydrin or Lea D11) is regulated by abscisic acid (ABA) and desiccation. The corresponding transcript and protein is highly inducible in vegetative and callus tissue. To analyse the mechanism of CDeT6-19 regulation its promoter was fused to the beta-glucuronidase reporter gene (GUS) and introduced by PEG (polyethylene glycol) into protoplasts of Craterostigma or tobacco. With 889 bp of promoter sequence the GUS expression was significantly stimulated by ABA treatment in transient expression assays. ABA responsiveness was still observed with shorter promoter fragments, although they gave rise to lower GUS activities. Sequence comparisons with promoters from related genes of other species identified the conservation of potential ABA-responsive elements. In tobacco and Craterostigma plants stably transformed with CDeT6-19 promoter constructs a basal GUS activity is observed. However, GUS expression is enhanced by ABA or drying treatment of leaf tissues. In tobacco high promoter activity was observed in mature seeds (embryos) and in pollen.
Abscisic Acid↗
[Aging and procedural memory. Study of a series of tests on microcomputers].
The authors have assessed perceptual motor tasks involving the learning of the mouse control by locking at a Macinthosh computer screen during three consecutive sessions. Tests were performed by 102 control subjects aged between 16 and 85 years. Concerning age, there was a significant time difference (ANOVA) but improvement was the same for all subjects. Educational level and IQP results didn't influence procedural performance. Men were faster in three tasks. We can argue that implicit learning abilities appear before explicit memory and within the adult life span there appears to be little significant deterioration in implicit memory abilitie.
Adolescent↗
Human cytomegalovirus UL97 kinase confers ganciclovir susceptibility to recombinant vaccinia virus.
We analyzed whether the phosphotransferase encoded by the UL97 open reading frame of human cytomegalovirus (HCMV) alone is sufficient to confer ganciclovir (GCV) susceptibility to a foreign virus. Two vaccinia virus recombinants (T1 and A5) containing the UL97 open reading frames from a GCV-sensitive HCMV and from a GCV-resistant strain were constructed. T1 exhibited a GCV-sensitive phenotype in plaque reduction assays, whereas A5 did not. Moreover, T1-infected cell cultures showed a strongly increased incorporation of [14C]GCV triphosphate into macromolecular DNA, compared with recombinant A5 or vaccinia virus controls, which could be inhibited by the addition of guanosine. This shows that UL97 kinase is the only additional gene product required to make vaccinia virus susceptible to GCV, and guanosine seems to be one natural substrate for the enzyme. The system described here should be very helpful for fast and detailed functional analyses of UL97 mutations found in GCV-resistant HCMV isolates.
Base Sequence↗
Rheumatic heart disease and Sneddon's syndrome.
BACKGROUND: As the pathogenesis of Sneddon's syndrome is unknown, research for associated disease can facilitate our understanding. CASE DESCRIPTION: Of nine patients with Sneddon's syndrome, three had rheumatic heart disease (mitral valve stenosis, regurgitation, or both) due to rheumatic fever or Sydenham's chorea. Transient anticardiolipin antibodies or positive skin lupus band test were present. CONCLUSIONS: Sneddon's syndrome can have multiple causes. In some patients, rheumatic heart disease is a possible causal association.
Adult↗
[Myxoma of the left atrium with neurologic manifestations: 8 cases].
A cohort of 8 patients with myxoma of the left atria and neurological manifestations is reported. Cerebral ischaemia, sometimes responsible for epileptic seizures, led to the discover of the myxoma (5 cases) or recurrence after exeresis (1 case) with imaging evidence of cerebral infarction in 5 cases. The first manifestation was a retinal embolism and temporary ischaemia in 1 case and pulmonary embolism with regressive cerebral ischaemia in another case with bilateral myxoma. Some clinical particularities should be underlined including exercise-induced neurological defect (3 cases), systemic embolism associated with cerebral infarction (3 cases), migraine headache as the initial manifestation (1 case) preceding by a pseudolupic syndrome suggesting the possibility of cerebral vasculitis or infectious endocarditis (1 case). The prognosis depends on the risk of recurrent atrial tumour formation (1 case). Metastases are rare. Multiple cerebral aneurysms (3 cases) did not lead to haemorrhagic complications.
Adult↗
[Spelling impairments. Neuropsychological study in two adolescents with developmental dysgraphia].
Two adolescents 14 and 16 years of age presented with isolated developmental agraphia. The spelling errors were correlated with the degree of orthographic ambiguity and with the word frequency as in acquired agraphia. Patients used to simplify the words spelling and to follow the phoneme-grapheme conversion. The deficit is interpreted as a failure of a selective visual memory for irregular words, representing a developmental graphemic logogene impairment. The better performance of reading is interpreted in relation to phonological system integrity which could better supply the grapheme phoneme conversion of reading even for irregular words. The ambiguous and irregular words recognition during reading appeared easier than their spelling during writing. Short term and working memory for irregular words appeared normal; the deficit occurred only for the long term recall after 20 minutes. Learning of 20 irregular words was made possible in one case by selective reminding of the errors. In spite of normal MRI, a developmental disorder involving the angular gyrus is proposed as for acquired lexical agraphia in adults.
Adolescent↗
[Opiates for epidural analgesia: for or against?].
Epidural opiate administration is routinely used by many anaesthesiologists involved in obstetric anaesthesia. Epidural injection of a local anaesthetic combined with an opioid generates a more rapid onset of more profound analgesia with little motor blockade. Thus pain relief lasts longer than after either drug alone. A combination of dilute concentrations of bupivacaine and opioids lowers the risk of systemic local anaesthetic toxicity significantly. Fentanyl was the first opioid widely used as an adjunct to local anaesthetics for labour analgesia. An initial dose of fentanyl 50 micrograms combined with 0.25% or 0.125% bupivacaine can produce good initial analgesia for most laboring parturients. A continuous infusion of 0.125% or 0.0625% bupivacaine with 1 microgram.ml-1 fentanyl at 10-12 ml.h-1 will maintain good pain relief throughout parturition. No adverse effects on either the mother or the neonate have been attributed to this technique. Recently, sufentanil was introduced in obstetric analgesia. Sufentanil appears to induce a faster onset of more profound, long lasting analgesia with extremely low concentrations of bupivacaine than that with fentanyl. The reduction of the total amount of bupivacaine is correlated with a significant decrease in motor blockade and instrumental deliveries. There were no adverse maternal or fetal effects and umbilical cord levels were too low to be detected.
Adult↗
NMR evidence for universal nonclassical critical behavior of incommensurately modulated crystals.
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Journal Article↗
Posterior uveitis, paraneoplastic encephalomyelitis and auto-antibodies reacting with developmental protein of brain and retina.
We report a 68-year-old woman who presented with posterior uveitis, cerebellar ataxia, dysautonomia, peripheral neuropathy and undifferentiated carcinoma. Autopsy showed slight brain inflammatory changes and severe Purkinje cell degeneration. By immunocytochemistry, the serum and CSF contained antibodies that reacted with the cytoplasm of cells in the brain and retina of rat. Some neurons and glial cells were stained. However, the most labelled cells were immature cells of the subventricular layers of the dentate gyrus, olfactory bulb and lateral ventricles. In rat retina, the plexiform layers and cells of the inner granular layer were stained. E15 rat embryo showed diffuse staining of post-mitotic cells and process in the central and peripheral nervous system. With the patient's IgG, various bands of 45, 60, 70 and 135 kDa apparent molecular weight were demonstrated on immunoblots of adult human, adult and E15 embryonic rat brain and rat and bovine retina. Eluates of tissue bound IgG labelled the same bands.
Aged↗
Analysis of a desiccation and ABA-responsive promoter isolated from the resurrection plant Craterostigma plantagineum.
The resurrection plant Craterostigma plantagineum can recover from severe desiccation within 24 h of contact with water, and it is used as a model system to analyse desiccation tolerance in higher plants. During drying or ABA treatment a specific set of transcripts accumulates rapidly in leaves and other tissues. In order to study transcriptional mechanisms of stress-induced gene expression one gene (CDeT27-45) was selected for promoter analysis. Chimeric gene fusions were constructed of the CDeT27-45 promoter and beta-glucuronidase or luciferase. These constructs were tested in a homologous transient expression system which allowed the identification of promoter elements conferring ABA inducibility. By introducing the chimeric gene fusions into tobacco via Agrobacterium-mediated transformation we found that the promoter activity is under strict tissue-specific and developmental control. In tobacco the promoter was only active in developing embryos and in mature pollen grains-two tissues which are naturally desiccation tolerant in tobacco. The specific temporal expression pattern was attributed to particular 5' upstream sequences. The promoter analysis presented here should allow the separation of important regulatory components as a first step in dissecting events in the signal transduction chain.
Abscisic Acid↗
[Fatal peripheral neuropathy with predominant motor involvement associated with anti-MAG IgM monoclonal gammapathy].
A 75 year old woman died of predominantly motor peripheral neuropathy with amyotrophy and fasciculations progressing to tetraplegia and death within 19 months. There was a mild distal sensory loss. At electrophysiology, the pattern was initially demyelinating and later became axonal. Nerve biopsy disclosed severe myelinated and unmyelinated fiber loss with wallerian degeneration. The remaining fibers had demyelination widening of the external myelin lamellae and intense hypermyelination. Serum contained an anti-MAG monoclonal IgM reacting with SGPG. Two siblings without monoclonal gammopathy had died of definite amyotrophic lateral sclerosis. This family association is discussed.
Aged↗
The PUR element stimulates transcription and is a target for single strand-specific binding factors conserved among vertebrate classes.
The PUR element has originally been defined in human, as a purine-rich motif present in a DNA replication initiation zone, whose purine strand is capable of binding a single strand-specific factor termed Pur, present in HeLa cell nuclear extracts. We have identified a related DNA element, in the 5' region of the quail clusterin gene, for its positive influence on the transcription of this gene. In the present work, we show that this element does correspond to a novel cis-element of transcription, still active when placed in an heterologous promoter. We also present a series of evidences showing that the avian PUR-specific binding factors are closely related to those previously identified in human. The human Pur alpha protein is capable of binding the quail clusterin PUR element as well as the human c-myc gene-derived PUR element. UV-crosslinking and Southwestern analyses reveal that the Pur factors present in HeLa and avian cells are closely related. The physical interactions with the PUR motif of Pur alpha and of the avian Pur factor are identical, as shown by PUR mobility-shift assay and methylation interference. Our results suggest that, in addition to their possible involvement in the initiation of DNA replication, these Pur factors are likely to act as transcription trans-activators.
Animals↗
H-DNA can act as a transcriptional insulator.
The polypurine/polypyrimidine DNA stretches with repetitive sequences (H palindromes) can adopt triplex-mediated folded structures called H-DNA. H palindromes are more represented than expected for a random distribution of bases in eucaryotic genomes, suggesting that they could ensure some biological function. Most studies have focused attention on their possible involvement in the control of transcription because of their particularly high frequency in the 5'-flanking sequences of genes. Using the (5'-TTCCC-3')n sequence present in the upstream region of several genes, this work concludes to a novel potentiality of H palindromes: The strong ability to disrupt the cooperation between proximal elements initiating transcription and distal elements enhancing transcription over a long distance. We present three structural features of the TTCCC repeat likely to explain such an activity: (1) the visualization by electron microscopy showing that a long H palindrome spontaneously forms higher order tertiary structures; (2) the fact that this structure is a target for specific nuclear proteins displaying an affinity for single-stranded polypyrimidines; and (3) the preferential localization of the genomic TTCCC repetitive sequences at the level of chromosomal matrix attachment regions (MARs). We propose that H-DNA can insulate some genetic loci from influences of their chromosomal environment, and belongs to a subclass of genomic matrix attachment regions.
Animals↗