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PubMed2006

Systematic significance of seed morphology in veronica (plantaginaceae): a phylogenetic perspective.

BACKGROUND AND AIMS: A new infrageneric rearrangement for Veronica has been proposed based on the most recent evidence from DNA sequence data, morphological evidence, and biogeographical considerations. Looking for morphological synapomorphies for each monophyletic subgenus has been problematic, due to difficulties arising from widespread homoplasy (mainly parallel evolution). In an attempt to overcome these difficulties, previously underexplored morphological characters are starting to be studied in more depth. METHODS: A molecular phylogenetic hypothesis was used based on sequences of ITS (nuclear ribosomal DNA) and plastid trnL-F regions, as a framework to test the use of seed coat ultrastructure (studied under scanning electron microscope) in the systematics of the genus. A sample of 132 taxa representing ten of the 13 subgenera in Veronica, excluding the species of the southern hemisphere Hebe complex and the exclusively North American subgenus Synthyris, was studied. KEY RESULTS AND CONCLUSIONS: The results demonstrate that, in many cases, the ultrastucture of the testa can be employed to assess relationships of taxa within the genus, and the character provides additional support for molecular trees. Further characters relevant for the classification of Veronica, i.e. base chromosome number, iridoid chemical data, life cycle, inflorescence position, have been taken into consideration in a discussion where an attempt is made to highlight the best traits to characterize each subgenus investigated.

Classification↗

PubMed2005

Areal specialization of pyramidal cell structure in the visual cortex of the tree shrew: a new twist revealed in the evolution of cortical circuitry.

Cortical pyramidal cells, while having a characteristic morphology, show marked phenotypic variation in primates. Differences have been reported in their size, branching structure and spine density between cortical areas. In particular, there is a systematic increase in the complexity of the structure of pyramidal cells with anterior progression through occipito-temporal cortical visual areas. These differences reflect area-specific specializations in cortical circuitry, which are believed to be important for visual processing. However, it remains unknown as to whether these regional specializations in pyramidal cell structure are restricted to primates. Here we investigated pyramidal cell structure in the visual cortex of the tree shrew, including the primary (V1), second (V2) and temporal dorsal (TD) areas. As in primates, there was a trend for more complex branching structure with anterior progression through visual areas in the tree shrew. However, contrary to the trend reported in primates, cells in the tree shrew tended to become smaller with anterior progression through V1, V2 and TD. In addition, pyramidal cells in V1 of the tree shrew are more than twice as spinous as those in primates. These data suggest that variables that shape the structure of adult cortical pyramidal cells differ among species.

Animals↗

PubMed2005

Pathophysiology of posttraumatic temporal lobe lesions.

BACKGROUND: Posttraumatic parenchymal lesions in the temporal lobe may cause neurologic deterioration. An analysis was made of the natural evolution of this type of lesion, with emphasis on its 2 components: hemorrhage (hyperdense on computed tomography [CT]), and edema and necrosis (hypodense on CT). The clinical repercussions were studied, and the factors that might influence such evolution were investigated. METHODS: Forty head-injured patients with temporal lobe lesions admitted within 12 hours after the injury were selected in a prospective manner. Computed tomography scans were systematically repeated within the first 36 hours and at 7 and 30 days postinjury. Factors such as interval between injury and the first CT scan, age, velocity of the injury, alcohol consumption, coagulation abnormalities, and the presence of decompressive measures were compared between the patients that had enlargement of the hemorrhage and those who did not. Increase in hypodensity was compared with that in hyperdensity. RESULTS: Fourteen patients showed enlargement of the hemorrhage. In all cases but one, the interval between injury and admission was 3 hours or less. Other factors had no statistical significance as predisposing causes for such enlargement. In approximately half of the cases, the hypodense component increased in the first 36 hours and continued increasing until the end of the first week. Evolution of the hypodense component was not dependent on behavior of the hemorrhage, surgical drainage, or diameter of the hemorrhagic lesion. CONCLUSIONS: The natural evolution of the hyperdense component of temporal lobe lesions was to enlarge within the first few hours after the injury. Edema and necrosis developed more slowly and with no significant clinical manifestations.

Age Factors↗

PubMed2026

Evolutionary and resistance dynamics in oligometastatic and oligoprogressive cancer treated with stereotactic radiotherapy and systemic therapies: A systematic review and focused meta-analysis.

BACKGROUND: Oligometastatic and oligoprogressive disease treated with stereotactic ablative radiotherapy (SABR) represents a clinically heterogeneous entity. Increasing evidence suggests that anatomical definitions alone may not adequately capture underlying biological diversity. This systematic review aimed to synthesize translational evidence exploring evolutionary dynamics, resistance mechanisms, and biomarker-driven stratification in patients treated with SABR. METHODS: A systematic literature review was performed including prospective and retrospective studies evaluating translational biomarkers in oligometastatic or oligoprogressive settings treated with SABR. Studies assessing genomic, transcriptomic, circulating or immune-related biomarkers were included. Data were summarized qualitatively according to predefined translational domains: (i) evolutionary dynamics under systemic therapy pressure, (ii) baseline biological stratification, (iii) longitudinal circulating biomarkers, and (iv) systemic immune remodeling. Exploratory quantitative visual syntheses were performed using reported hazard ratios when conceptually comparable endpoints were available. RESULTS: 19 studies comprising 1527 patients were included. Across tumor types and treatment contexts, translational analyses consistently indicated that anatomically defined oligometastatic states encompass biologically distinct subgroups with different risks of systemic progression. Studies evaluating oligoprogression under ongoing systemic therapy suggested a distinction between spatially constrained resistance and systemic molecular escape, supported by circulating tumor DNA and tissue- or plasma-based molecular profiling (including genomic and transcriptomic analyses). Baseline biological features, including adverse genomic signatures and circulating biomarkers, were associated with inferior progression outcomes despite metastasis-directed therapy. Longitudinal biomarkers provided early signals of treatment response and systemic control. Immune remodeling after SABR showed context-dependent effects, both systemic immune activation and treatment-related immunosuppression reported across studies.

Humans↗

PubMed2004

Similar rates but different modes of sequence evolution in introns and at exonic silent sites in rodents: evidence for selectively driven codon usage.

In mammals divergence at fourfold degenerate sites in codons (K(4)) and intronic sequence (K(i)) are both used to estimate the mutation rate, under the supposition that both evolve neutrally. Does it matter which of these we use? Using either class of sequence can be defended because (1) K(4) is the same as K(i) (at least in rodents) and (2) there is no selectively driven codon usage (hence no systematic selection on third sites). Here we re-examine these findings using 560 introns (for 136 genes) in the mouse-rat comparison, aligned by eye and using a new maximum likelihood protocol. We find that the rate of evolution at fourfold sites and at intronic sites is similar in magnitude, but only after eliminating putatively constrained sites from introns (first introns and sites flanking intron-exon junctions). Any approximate congruence between the two rates is not, however, owing to an underlying similarity in the mode of sequence evolution. Some dinucleotides are hypermutable and differently abundant in exons and introns (e.g., CpGs). More importantly, after controlling for relative abundance, all dinucleotides starting with A or T are more prevalent in mismatches in exons than in introns, whereas C-starting dinucleotides (except CG) are more common in introns. Although C content at intronic sites is lower than at flanking fourfold sites, G content is similar, demonstrating that there exists a strong strand-specific preference for C nucleotides that is unique to exons. Transcription-coupled mutational processes and biased gene conversion cannot explain this, as they should affect introns and flanking exons equally. Therefore, by elimination, we propose this to be strong evidence for selectively driven codon usage in mammals.

Animals↗

PubMed1991

[Surgery of pulmonary metastasis from malignant melanoma. Results and criteria of surgical excision].

Lung metastases from malignant melanoma are frequent and they often inaugurate the metastatic stage. Exceptionally, they present as one or a few nodules, and in the absence of any other secondary lesion these cases raise the problem of surgical eradication. A retrospective multicentre study was carried out in a series of 38 patients and its results were compared to the data obtained from a review of 435 published cases in order to assess the value of surgery in terms of survival and to delimit its indications as closely as possible. Our series of 38 patients comprised 20 men and 18 women aged from 22 to 93 years (mean 51 years, median 55 years). The primary tumour was located in the trunk in 47 p. 100 of the cases; it was nodular in 33 p. 100 and superficial but extensive in 37.5 p. 100. The time elapsed before the metastases appeared varied from 0 to 108 months (median 40 months). Surgery had been radical in 70 p. 100 of the patients and usually limited, tumorectomies and segmentectomies accounting for 51 p. 100 of the operations. RESULTS. In this series the duration of survival varied between 2 and 144 months (mean 26 months, median close to 15 months), with a 20 p. 100 probability of survival at 5 years (fig. 1). Disease free survival varied from 0 to 144 months (mean 22.5 months, median 10.5 months) (fig. 2, curve 1). The parameters of response as regards patients, primary tumour, metastases and treatment were analysed. Response was uninfluenced by sex and slightly influenced by age, with a difference of borderline significance between subjects under and over 50. The primary tumour characteristics did not affect survival, and the features of metastases were of extremely varied importance. The number of operable metastases was not determinant. On the other hand, the presence of mediastinal lesions, either isolated or associated with lung lesions, worsened the prognosis of terms of survival and much more significantly so in terms of remission (fig. 3 and 4). The evaluation of evolutive characteristics, such as date of appearance and tumour doubling time, was inconclusive. Survival was of the same duration after wide and limited surgery, so that tumorectomy or segmentectomy should preferably be performed. The results of surgical treatment were determinant, with a highly significant difference in survival between radical and incomplete surgery (fig. 5 and fig. 2, curve 2). DISCUSSION. The median survival of patients operated upon for lung metastases is diversely evaluated in the literature as 8 to 29 months (table V), the mean figure of 16 months being virtually the same as that of our series. In this, as in most of the previously published series, the maximum duration of survival was beyond 8 to 10 years. The mean survival rate at 5 years is very close to the one we have recorded (20 p. 100) (table V). Compared with other treatments of lung metastases, surgery may be considered as capable of prolonging survival by 6 months; this is not much unless we add the possibility of a 5-year survival in 1 out of 5 operated patients and the possibility of a survival exceeding 8 or 10 years in 2 to 5 p. 100 of the cases. Some prognostic factors seem to constitute positive or negative criteria of operability. This is the case with mediastinal lesions which may consist of a metastasis of metastasis or of a lymph node invasion associated or not with the lung lesion, but in any case correspond to the involvement of more than one site. Mediastinal lesions must be systematically looked for and treated as contraindications of surgery, as shown by the differences in survival recorded in our series. Opinions differ as regards the value of evolutive parameters of the metastasis. For some authors, a more than 5 years interval before the metastasis appears is associated with a good chance of prolonged survival, whereas a less than 6 months or 1 year interval reflects a steadily high progressiveness and in practice precludes surgery. The value of the

Adult↗

PubMed2005

Rapid evolution of noncoding RNAs: lack of conservation does not mean lack of function.

The mammalian transcriptome contains many non-protein-coding RNAs (ncRNAs), but most of these are of unclear significance and lack strong sequence conservation, prompting suggestions that they might be non-functional. However, certain long functional ncRNAs such as Air and Xist are also poorly conserved. In this article, we systematically analyzed the conservation of several groups of functional ncRNAs, including miRNAs, snoRNAs and longer ncRNAs whose function has been either documented or confidently predicted. As expected, miRNAs and snoRNAs were highly conserved. By contrast, the longer functional non-micro, non-sno ncRNAs were much less conserved with many displaying rapid sequence evolution. Our findings suggest that longer ncRNAs are under the influence of different evolutionary constraints and that the lack of conservation displayed by the thousands of candidate ncRNAs does not necessarily signify an absence of function.

Animals↗

PubMed1998

Effects of branch length errors on the performance of phylogenetically independent contrasts.

We examined Type I error rates of Felsenstein's (1985; Am. Nat. 125:1-15) comparative method of phylogenetically independent contrasts when branch lengths are in error and the model of evolution is not Brownian motion. We used seven evolutionary models, six of which depart strongly from Brownian motion, to simulate the evolution of two continuously valued characters along two different phylogenies (15 and 49 species). First, we examined the performance of independent contrasts when branch lengths are distorted systematically, for example, by taking the square root of each branch segment. These distortions often caused inflated Type I error rates, but performance was almost always restored when branch length transformations were used. Next, we investigated effects of random errors in branch lengths. After the data were simulated, we added errors to the branch lengths and then used the altered phylogenies to estimate character correlations. Errors in the branches could be of two types: fixed, where branch lengths are either shortened or lengthened by a fixed fraction; or variable, where the error is a normal variate with mean zero and the variance is scaled to the length of the branch (so that expected error relative to branch length is constant for the whole tree). Thus, the error added is unrelated to the microevolutionary model. Without branch length checks and transformations, independent contrasts tended to yield extremely inflated and highly variable Type I error rates. Type I error rates were reduced, however, when branch lengths were checked and transformed as proposed by Garland et al. (1992; Syst. Biol. 41:18-32), and almost never exceeded twice the nominal P-value at alpha = 0.05. Our results also indicate that, if branch length transformations are applied, then the appropriate degrees of freedom for testing the significance of a correlation coefficient should, in general, be reduced to account for estimation of the best branch length transformation. These results extend those reported in Díaz-Uriarte and Garland (1996; Syst. Biol. 45:27-47), and show that, even with errors in branch lengths and evolutionary models different from Brownian motion, independent contrasts are a robust method for testing hypotheses of correlated evolution.

Computer Simulation↗

PubMed2005

Punctuated duplication seeding events during the evolution of human chromosome 2p11.

Primate genomic sequence comparisons are becoming increasingly useful for elucidating the evolutionary history and organization of our own genome. Such studies are particularly informative within human pericentromeric regions--areas of particularly rapid change in genomic structure. Here, we present a systematic analysis of the evolutionary history of one approximately 700-kb region of 2p11, including the first autosomal transition from pericentromeric sequence to higher-order alpha-satellite DNA. We show that this region is composed of segmental duplications corresponding to 14 ancestral segments ranging in size from 4 kb to approximately 115 kb. These duplicons show 94%-98.5% sequence identity to their ancestral loci. Comparative FISH and phylogenetic analysis indicate that these duplicons are differentially distributed in human, chimpanzee, and gorilla genomes, whereas baboon has a single putative ancestral locus for all but one of the duplications. Our analysis supports a model where duplicative transposition events occurred during a narrow window of evolution after the separation of the human/ape lineage from the Old World monkeys (10-20 million years ago). Although dramatic secondary dispersal events occurred during the radiation of the human, chimpanzee, and gorilla lineages, duplicative transposition seeding events of new material to this particular pericentromeric region abruptly ceased after this time period. The multiplicity of initial duplicative transpositions prior to the separation of humans and great-apes suggests a punctuated model for the formation of highly duplicated pericentromeric regions within the human genome. The data further indicate that factors other than sequence are important determinants for such bursts of duplicative transposition from the euchromatin to pericentromeric regions.

Animals↗

PubMed2003

Evolution and classification of P-loop kinases and related proteins.

Sequences and structures of all P-loop-fold proteins were compared with the aim of reconstructing the principal events in the evolution of P-loop-containing kinases. It is shown that kinases and some related proteins comprise a monophyletic assemblage within the P-loop NTPase fold. An evolutionary classification of these proteins was developed using standard phylogenetic methods, analysis of shared sequence and structural signatures, and similarity-based clustering. This analysis resulted in the identification of approximately 40 distinct protein families within the P-loop kinase class. Most of these enzymes phosphorylate nucleosides and nucleotides, as well as sugars, coenzyme precursors, adenosine 5'-phosphosulfate and polynucleotides. In addition, the class includes sulfotransferases, amide bond ligases, pyrimidine and dihydrofolate reductases, and several other families of enzymes that have acquired new catalytic capabilities distinct from the ancestral kinase reaction. Our reconstruction of the early history of the P-loop NTPase fold includes the initial split into the common ancestor of the kinase and the GTPase classes, and the common ancestor of ATPases. This was followed by the divergence of the kinases, which primarily phosphorylated nucleoside monophosphates (NMP), but could have had broader specificity. We provide evidence for the presence of at least two to four distinct P-loop kinases, including distinct forms specific for dNMP and rNMP, and related enzymes in the last universal common ancestor of all extant life forms. Subsequent evolution of kinases seems to have been dominated by the emergence of new bacterial and, to a lesser extent, archaeal families. Some of these enzymes retained their kinase activity but evolved new substrate specificities, whereas others acquired new activities, such as sulfate transfer and reduction. Eukaryotes appear to have acquired most of their kinases via horizontal gene transfer from Bacteria, partly from the mitochondrial and chloroplast endosymbionts and partly at later stages of evolution. A distinct superfamily of kinases, which we designated DxTN after its sequence signature, appears to have evolved in selfish replicons, such as bacteriophages, and was subsequently widely recruited by eukaryotes for multiple functions related to nucleic acid processing and general metabolism. In the course of this analysis, several previously undetected groups of predicted kinases were identified, including widespread archaeo-eukaryotic and archaeal families. The results could serve as a framework for systematic experimental characterization of new biochemical and biological functions of kinases.

Amino Acid Sequence↗

PubMed2005

Evolvability of cell specification mechanisms.

The architecture of gene action during development is relevant to phenotypic evolution as it links genotype to morphological phenotype. Analysis of development at the level of cell fate specification mechanisms illuminates some of the properties of developmental evolution. In this article, we first review examples of evolutionary change in mechanisms of cell fate specification, with an emphasis on evolution in the dependence on inductive signaling and on evolution of the mechanisms that result in spatial asymmetries. We then focus on properties of development that bias possible phenotypic change and present how the distribution of phenotypes that are available by mutational change of the starting genotype can be experimentally tested by systematic mutagenesis. We finally discuss ways in which selection pressures on phenotypes can be inferred from a comparison of the phenotypic spectrum found on mutation with that found in the wild.

Animals↗

PubMed2003

A reticular rhapsody: phylogenic evolution and nomenclature of the RTN/Nogo gene family.

Reticulon (RTN) genes code for a family of proteins relatively recently described in higher vertebrates. The four known mammalian paralogues (RTN1, -2, -3, and -4/Nogo) have homologous carboxyl termini with two characteristic large hydrophobic regions. Except for RTN4-A/Nogo-A, thought to be an inhibitor for neurite outgrowth, restricting the regenerative capabilities of the mammalian CNS after injury, the functions of other family members are largely unknown. The overall occurrence of RTNs in different phyla and the evolution of the RTN gene family have hitherto not been analyzed. Here we expound data showing that the RTN family has arisen during early eukaryotic evolution potentially concerted to the establishment of the endomembrane system. Over 250 reticulon-like (RTNL) genes were identified in deeply diverging eukaryotes, fungi, plants, and animals. A systematic nomenclature for all identified family members is introduced. The analysis of exon-intron arrangements and of protein homologies allowed us to isolate key steps in the history of these genes. Our data corroborate the hypothesis that present RTNs evolved from an intron-rich reticulon ancestor mainly by the loss of different introns in diverse phyla. We also present evidence that the exceptionally large RTN4-A-specific exon 3, which harbors a potent neurite growth inhibitory region, may have arisen de novo approximately 350 MYA during transition to land vertebrates. These data emphasize on the one hand the universal role of reticulons in the eukaryotic system and on the other hand the acquisition of putative new functions through acquirement of novel amino-terminal exons.

Amino Acid Sequence↗

PubMed2003

Do fishes have nociceptors? Evidence for the evolution of a vertebrate sensory system.

Nociception is the detection of a noxious tissue-damaging stimulus and is sometimes accompanied by a reflex response such as withdrawal. Pain perception, as distinct from nociception, has been demonstrated in birds and mammals but has not been systematically studied in lower vertebrates. We assessed whether a fish possessed cutaneous nociceptors capable of detecting noxious stimuli and whether its behaviour was sufficiently adversely affected by the administration of a noxious stimulus. Electrophysiological recordings from trigeminal nerves identified polymodal nociceptors on the head of the trout with physiological properties similar to those described in higher vertebrates. These receptors responded to mechanical pressure, temperatures in the noxious range (more than 40 degrees C) and 1% acetic acid, a noxious substance. In higher vertebrates nociceptive nerves are either A-delta or C fibres with C fibres being the predominating fibre type. However, in the rainbow trout A-delta fibres were most common, and this offers insights into the evolution of nociceptive systems. Administration of noxious substances to the lips of the trout affected both the physiology and the behaviour of the animal and resulted in a significant increase in opercular beat rate and the time taken to resume feeding, as well as anomalous behaviours. This study provides significant evidence of nociception in teleost fishes and furthermore demonstrates that behaviour and physiology are affected over a prolonged period of time, suggesting discomfort.

Acetic Acid↗

PubMedDate not supplied

[Fever of unknown origin. Presentation of 180 pediatric cases].

Fever of unknown origin (FUO) is a frequent disorder in pediatric age. FUO is defined as the presence of fever over 38.4 centigrades in a patient for more than three weeks in which the etiology remains undetermined. From 30.736 consecutive admittances into our hospital, 180 patients with FUO were detected, and studied in a systematized way and according to a predetermined protocol. FUO was commonly found in children under six years of age. Our patients presented fever from three weeks to six and a half years of evolution; however, in the vast majority of the cases (n = 115) fever had a three weeks course. Several symptoms and physical manifestations other than fever were observed in our patients but they were widely variable and nonspecific. Infectious diseases were the commonest etiological factor encountered; among them, thyroid fever, and urinary tract infections were the most frequent infectious disorder found; in four children fever was associated to ampicillin administration; in 19 patients, fever was no demonstrated. A large number of laboratory investigations were done in the diagnosis of neoplastic diseases. We think that the study of a patient with FUO requires of a systematized approach.

Adolescent↗

PubMed2000

Intratumoral genetic heterogeneity and progression of endometrioid type endometrial adenocarcinomas.

OBJECTIVES: Development of genetic heterogeneity is one mechanism whereby tumors may acquire increasing aggressiveness during neoplastic progression. In this study we relate development of intratumoral genetic heterogeneity to invasion and metastatic spread of sporadic endometrioid (type I) endometrial adenocarcinomas. METHODS: Microsatellite unstable adenocarcinomas underwent detailed microsatellite allelotype mapping with reconstruction of neoplastic lineages using maximum parsimony analysis. RESULTS: Within individual patients, tumor allelotypes sometimes varied between regions of histologically identical tumor, indicating that genotypic variation may reflect differences inapparent by histology. Comparison of noninvasive (surface/luminal) with invasive (myometrial invasion or metastasis) carcinoma showed highly related genotypes in 3/8 cases in which the invasive component can be recognized as evolved from the superficial tumor lineage by progressive clonal selection. In 3/8 cases superficial and invasive genotypes independently evolved different sets of altered microsatellites, indicating either divergence at an early stage in tumor evolution or independent selection events. A total of 2/8 cases had random patterns of marker distribution between sampled areas that were not informative in delineating systematic relationships between surface and invasive tumor. CONCLUSIONS: We conclude from these results that endometrial tumor progression may occur through physical extension of existing clones or through creation of new subclones with altered growth properties. The latter occurs in about half of cases, where myometrial invasion may select for particular clones that are poorly represented on the luminal surface.

Alleles↗

PubMed1994

Technology assessment of endoscopic surgery.

Endoscopic surgery is considered a milestone in the evolution of surgical technique in nearly all fields of surgery. However, the inappropriate use of the new technology in medicine has also been heavily criticised. Systematic technology assessment of endoscopic surgical techniques is mandatory to prove the real benefits and complications, so defining the indications for their appropriate use. This article describes methods of technology assessment suitable for endoscopic techniques with emphasis on relevant endpoints for surgeons and patients. The general stages of a comprehensive technology assessment include: 1. feasibility (safety and technical performance) 2. efficacy (patient benefits in pioneering places) 3. effectiveness (patient benefits in average hospitals in the community as a whole) and 4. economic evaluation (cost-benefit analyses). We used the example of laparoscopic cholecystectomy to describe the methods of technology assessment. A cohort study on 500 patients revealed that laparoscopic cholecystectomy is as safe as the conventional standard open technique. The results on efficacy strongly support the hypothesis of more comfort and less trauma with the endoscopic technique. Major endpoints evaluated were postoperative pain, convalescence, fatigue and quality of life. Data on effectiveness and economics are still in a "premature" state and should be the subject of further analyses. It is concluded, that other disciplines such as neurosurgery should evaluate their endoscopic surgical techniques according to the rules of technology assessment outlined in this paper.

Cholecystectomy, Laparoscopic↗

PubMed1987

Non-hereditary multiple telangiectasias of the central nervous system. Report of two clinicopathological cases.

We describe 2 clinicopathological cases of non-hereditary multiple telangiectasias of the nervous system. In the first case, the general course of the disease was characterized by spells over a period of 7 years and the major lesions successively involved cranial nerves, spinal cord and brain. Neuropathological examination showed both ischemic and hemorrhagic changes. Systematized degenerative changes were found and were similar to those observed in spinocerebellar heredodegenerations (Friedreich's ataxia). In the second case, the 3 years of evolution were characterized by spells of the encephalitic type only. A review of the literature indicates the rarity of this kind of disease, the usual localization of capillary malformations and the clinical polymorphism (epilepsy, strokes, multifocal syndromes masquerading as multiple sclerosis). The pathogenesis of pathological changes is discussed.

Aged↗

PubMed2004

Visual word recognition: the first half second.

We used magnetoencephalography (MEG) to map the spatiotemporal evolution of cortical activity for visual word recognition. We show that for five-letter words, activity in the left hemisphere (LH) fusiform gyrus expands systematically in both the posterior-anterior and medial-lateral directions over the course of the first 500 ms after stimulus presentation. Contrary to what would be expected from cognitive models and hemodynamic studies, the component of this activity that spatially coincides with the visual word form area (VWFA) is not active until around 200 ms post-stimulus, and critically, this activity is preceded by and co-active with activity in parts of the inferior frontal gyrus (IFG, BA44/6). The spread of activity in the VWFA for words does not appear in isolation but is co-active in parallel with spread of activity in anterior middle temporal gyrus (aMTG, BA 21 and 38), posterior middle temporal gyrus (pMTG, BA37/39), and IFG.

Adult↗