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2.
Nature ; 571(7765): E7, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31263274

ABSTRACT

Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.

3.
Nature ; 568(7753): 487-492, 2019 04.
Article in English | MEDLINE | ID: mdl-31019327

ABSTRACT

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.


Subject(s)
Carbon Dioxide/analysis , Carbon Sequestration , Geologic Sediments/chemistry , Biomass , Carbon Isotopes , Costa Rica , Geologic Sediments/microbiology , Helium
7.
Neurology ; 64(8): 1455-7, 2005 Apr 26.
Article in English | MEDLINE | ID: mdl-15851745

ABSTRACT

Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). We report a novel missense mutation in the PRNP gene (resulting in a G114V mutation in PrP) in members of a Uruguayan family with clinical and histopathologic features of prion disease. Affected individuals were characterized by an early age at onset, initial neuropsychiatric symptoms, late dementia with prominent pyramidal and extrapyramidal symptoms, and long disease duration.


Subject(s)
Amyloid/genetics , Brain/physiopathology , Genetic Predisposition to Disease/genetics , Mutation/genetics , Prion Diseases/genetics , Protein Precursors/genetics , Adolescent , Adult , Age of Onset , Amino Acid Substitution/genetics , Biopsy , Brain/metabolism , Brain/pathology , Chromosome Aberrations , DNA Mutational Analysis , Dementia/genetics , Dementia/pathology , Dementia/physiopathology , Disease Progression , Fatal Outcome , Female , Frontal Lobe/metabolism , Frontal Lobe/pathology , Frontal Lobe/physiopathology , Genetic Testing , Humans , Male , Personality Disorders/genetics , Personality Disorders/pathology , Personality Disorders/physiopathology , Prion Diseases/pathology , Prion Diseases/physiopathology , Prion Proteins , Prions , Pyramidal Tracts/metabolism , Pyramidal Tracts/pathology , Pyramidal Tracts/physiopathology , Uruguay
8.
Rev Neurol (Paris) ; 159(2): 199-202, 2003 Feb.
Article in French | MEDLINE | ID: mdl-12660573

ABSTRACT

We report the fifth French case of fatal familial insomnia, characterized by a mutation at codon 178 of prion protein gene and by heterozygoty (Met/Val) at codon 129. The clinical picture included cerebellar ataxia, dysautonomia and frontal lobe syndrome. Prion protein gene analysis was performed in order to support a diagnosis of Creutzfeldt-Jakob disease and assert the diagnosis of fatal familial insomnia. Neuropathologic analysis showed unusual changes including severe neuronal loss in the inferior olive and the dentate nucleus, and absence of obvious lesions in the thalamus. Moreover, spongiform changes were moderate in the superior temporal cortex and the occipital cortex. There was no spongiform change in frontal cortex. Abnormal prion protein (PrP(res)) was mainly evidenced in the parietal cortex. Molecular genetic study of the PRNP gene should be performed in patients who present with a cerebellar ataxia of equivocal origin.


Subject(s)
Amyloid/genetics , Cerebellar Ataxia/genetics , Insomnia, Fatal Familial/genetics , Protein Precursors/genetics , Cerebellar Ataxia/pathology , Cerebral Cortex/pathology , Codon , Creutzfeldt-Jakob Syndrome/genetics , Creutzfeldt-Jakob Syndrome/pathology , Dentate Gyrus/pathology , France , Humans , Immunohistochemistry , Insomnia, Fatal Familial/pathology , Male , Middle Aged , Olivary Nucleus/pathology , Prion Proteins , Prions , Thalamus/pathology
9.
FEBS Lett ; 536(1-3): 61-5, 2003 Feb 11.
Article in English | MEDLINE | ID: mdl-12586339

ABSTRACT

Doppel protein has been discovered in prnp knock-out mouse lines, with overproduction of this protein in the brain causing ataxia and neurodegeneration. We investigated whether Doppel expression (i) affected or was affected by the course of prion propagation in neuroblastoma cells, or (ii) modulated Creutzfeldt-Jakob disease pathogenesis. No change in Doppel production was detected in N2a cells, before or after infection. Transient murine Doppel gene expression had no effect on N2a viability or PrP(Sc) production. A sensitive immunometric assay revealed low levels of Doppel in human brain, reflecting weak transcription of the corresponding gene. No difference in brain Doppel levels was observed between Creutzfeldt-Jakob disease patients and controls, adding further evidence that Doppel is unlikely to be involved in prion disease pathogenesis.


Subject(s)
Brain/metabolism , Creutzfeldt-Jakob Syndrome/metabolism , Prions/metabolism , Animals , Creutzfeldt-Jakob Syndrome/genetics , Female , GPI-Linked Proteins , Humans , Male , Mice , Neurons/metabolism , Prions/genetics , RNA, Messenger/biosynthesis , Scrapie/metabolism , Transcription, Genetic , Tumor Cells, Cultured
10.
Eur J Neurol ; 9(5): 457-62, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12220376

ABSTRACT

We report the molecular and phenotypic analysis of a French cluster of three cases of Creutzfeldt-Jakob disease (CJD), two of them occurring in 1998 in the same village and the other in 1995 in a neighboring village. Analyses of the occurrence of these events in a close area with less than 3000 inhabitants over the 1992-1999 notification period confirmed that they are rare. This could be explained either by a common source of contamination or by the coincidental occurrence of either sporadic or genetic CJD. We applied genetic analysis and brain PrPres typing to explore these CJD cases. The three patients did not carry any mutation in their prion protein gene coding sequence. All were homozygous for methionine at the polymorphic codon 129. Brain tissue was available from two cases that died in 1998. The two patients showed different PrPres profiles on Western blot and distinct clinico-pathological features. These findings do not support the conclusion that in these three cases, CJD was acquired from a unique source of contamination and suggest that concurrent occurrence of sporadic CJD accounted for this CJD cluster.


Subject(s)
Creutzfeldt-Jakob Syndrome/genetics , Mutation/genetics , PrPSc Proteins/genetics , Aged , Brain/metabolism , Brain/pathology , Brain/physiopathology , Cluster Analysis , Codon/genetics , Creutzfeldt-Jakob Syndrome/physiopathology , DNA Mutational Analysis , Female , France , Genetic Testing , Genotype , Humans , Male , Methionine/genetics , Middle Aged , Polymorphism, Genetic/genetics , PrPSc Proteins/metabolism
12.
Ann Neurol ; 49(2): 257-60, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11220747

ABSTRACT

The usefulness of the detection of 14-3-3 protein in the cerebrospinal fluid (CSF) in the diagnosis of Creutzfeldt-Jakob disease transmitted from human growth hormone was evaluated in 20 French patients. The 14-3-3 protein was rarely detectable within the first 3 months of the disease but always positive after 7 months associated with the aggravation of the disease and the occurrence of dementia. 14-3-3 detection was not predictive of the survival time of the patients. The genotype at PRNP codon 129 could influence the timing of appearance of the 14-3-3 protein in the CSF.


Subject(s)
Creutzfeldt-Jakob Syndrome/cerebrospinal fluid , Growth Hormone/therapeutic use , Tyrosine 3-Monooxygenase/cerebrospinal fluid , 14-3-3 Proteins , Creutzfeldt-Jakob Syndrome/drug therapy , Female , Humans , Male
13.
Hum Mutat ; 15(5): 482, 2000 May.
Article in English | MEDLINE | ID: mdl-10790216

ABSTRACT

Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). As the other sporadic or infectious prion disease forms, they are almost all characterized by the accumulation in the brain of an abnormal misfolded form of the patient's PrP. Brain extracts can often transmit the disease once inoculated in a recipient animal. Inherited prion diseases with Creutzfeldt-Jakob disease (CJD) phenotype are autosomal forms, although sporadic cases have been reported. We report three novel mutations of the PRNP gene in unrelated patients with clinical and histopathologic features of CJD. The three mutations were missense: c635G>A (E196K), c656G>A (V203I) and c680G>C (E211Q). Familial history of neurologic disorders was evidenced for patients carrying the E196K and E211Q mutations. E196K would be predicted to have more severe effects on protein stability than V203I and E211Q. These mutations expand the spectrum of mutations in PRNP and reduce the proportion of CJD patients in whom genetic alterations have not been found.


Subject(s)
Amino Acid Substitution/genetics , Amyloid/genetics , Creutzfeldt-Jakob Syndrome/genetics , Mutation, Missense/genetics , Protein Precursors/genetics , Aged , Female , Glutamic Acid/genetics , Glutamine/genetics , Humans , Isoleucine/genetics , Lysine/genetics , Male , Middle Aged , Phenotype , Prion Proteins , Prions , Valine/genetics
14.
Appl Opt ; 39(16): 2840-52, 2000 Jun 01.
Article in English | MEDLINE | ID: mdl-18345208

ABSTRACT

A procedure for the time-domain optical characterization of an inclusion in a scattering slab is investigated theoretically and experimentally. The method relies on the measurement of a contrast function, which is defined as the time-dependent relative change in the transmitted signal resulting from the presence of the inclusion. Analytical expressions for the contrast functions of absorptive and diffusive inclusions are obtained through a perturbation solution of the diffusion equation. This procedure is used successfully to determine the optical properties of absorptive, diffusive, and mixed inclusions located at midplane in a scattering slab by use of time-resolved transmittance measurements.

15.
Appl Opt ; 39(25): 4730-2, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-18350065

ABSTRACT

We introduce a technique called dual-spatial integration (DSI) that is used to isolate and enhance inclusions that differ only by their longitudinal placement within a scattering medium. DSI uses three different source-detector configurations to section a scattering medium into three longitudinal zones. This sectioning permits the extraction of structures close to surfaces and the enhancement of those structures located in the central part of the medium. Both the simulation and the experimental results indicate that DSI has potential interest for applications in biomedical imaging such as optical mammography.

16.
Rev Neurol (Paris) ; 155(2): 148-51, 1999 Feb.
Article in French | MEDLINE | ID: mdl-10226319

ABSTRACT

We studied the diagnostic value of detecting protein 14-3-3 and of assaying neuronal specific enolase (NSE) in the cerebrospinal fluid of 150 patients with suspected sporadic Creutzfeldt-Jakob disease registered in an epidemiology research program between 1991 and 1996. Sensitivity and specificity of these two tests were high. This study confirms results reported earlier and authorizes a new definition of Creutzfeldt-Jakob disease which gives protein 14-3-3 the same diagnostic value as EEG recordings for classifying sporadic cases.


Subject(s)
Cerebrospinal Fluid Proteins/analysis , Creutzfeldt-Jakob Syndrome/cerebrospinal fluid , Creutzfeldt-Jakob Syndrome/enzymology , Phosphopyruvate Hydratase/metabolism , Proteins/analysis , Tyrosine 3-Monooxygenase , 14-3-3 Proteins , Creutzfeldt-Jakob Syndrome/diagnosis , Electroencephalography , Epilepsies, Myoclonic/diagnosis , Humans , Predictive Value of Tests , Retrospective Studies
17.
Dement Geriatr Cogn Disord ; 10(1): 40-6, 1999.
Article in English | MEDLINE | ID: mdl-10068257

ABSTRACT

We explored simultaneously 14-3-3 protein, neuron-specific enolase (NSE), and one astroglial protein, S-100, recently proposed as Creutzfeld-Jakob disease (CJD) markers, in the cerebrospinal fluid (CSF) of 129 patients with suspected CJD. Cutoff values for NSE and S-100 were established at 25 and 2.5 ng/ml, respectively. The highest sensitivity was observed for S-100 (94.2%) followed by 14-3-3 (89.8%) and NSE (79.7%), while the highest specificity in CJD diagnosis was obtained with 14-3-3 protein (100%) as compared with NSE (91.5%) and S-100 (85.4%). No influence of sex, genotype at codon 129 of the prion protein gene, time between sampling, and death or disease duration has been found. Based on 90 cases initially referred as 'probable' or 'possible' CJD, with 14-3-3, NSE, or S-100 we could correctly discriminate between 'CJD' or 'non-CJD' categories in 94.4, 86.5, and 90% of the cases, respectively. When limited to 'possible CJD' cases, diagnosis based on one of the three CSF proteins was accurate in 98, 90.7 and 87.3%, respectively. In view of the fact that the CSF 14-3-3 protein test alone has the highest specificity and good sensitivity, it appears that there is no additional advantage at the moment to include NSE and/or S-100 protein in the exploration of clinically suspected CJD cases.


Subject(s)
Creutzfeldt-Jakob Syndrome/cerebrospinal fluid , Phosphopyruvate Hydratase/cerebrospinal fluid , Proteins/metabolism , S100 Proteins/cerebrospinal fluid , Tyrosine 3-Monooxygenase , 14-3-3 Proteins , Adult , Female , Humans , Immunochemistry , Male , Predictive Value of Tests
18.
Appl Opt ; 38(16): 3681-5, 1999 Jun 01.
Article in English | MEDLINE | ID: mdl-18319973

ABSTRACT

An analytical expression has been obtained that describes the time variation of time-resolved signals transmitted through or reflected by a homogeneous scattering slab as measured with a detection system having a square-impulse response. This expression can be used to improve the match between theoretical and experimental time-resolved signals measured with a system having a finite response time. It can also be used to assess the effect of a finite detection response time on the time-domain characterization of a turbid medium. The expression can be adapted to detection systems that are not time invariant.

19.
Appl Opt ; 38(16): 3686-93, 1999 Jun 01.
Article in English | MEDLINE | ID: mdl-18319974

ABSTRACT

A technique for discriminating between scattering and absorbing inclusions located in the center of a scattering slab is presented. The technique is based on an empirical model that provides a simple mathematical expression to describe the change in the time-resolved transmission resulting from the presence of an inclusion. Experimental results from various configurations show that the technique allows for proper recognition of the type of an inclusion whether it is scattering or absorbing. This technique is a significant step toward tissue differentiation.

20.
Appl Opt ; 38(19): 4247-51, 1999 Jul 01.
Article in English | MEDLINE | ID: mdl-18323907

ABSTRACT

A phantom based on a polyurethane system that replicates the optical properties of tissue for use in near-infrared imaging is described. The absorption properties of tissue are simulated by a dye that absorbs in the near infrared, and the scattering properties are simulated by TiO2 particles. The scattering and absorption coefficients of the plastic were measured with a new technique based on time-resolved transmission through two slabs of materials that have different thicknesses. An image of a representative phantom was obtained from time-gated transmission.

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