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PubMedDate not supplied

[Hereditary chorioretinal degeneration and nephronophthisis. The role of Senior-Löken syndrome].

Systematic clinical ocular examinations completed by electrophysiological studies were performed on fifty-five children with nephronophthisis. Twenty children, all under ten years of age, had tapetoretinal degeneration, either pure in fourteen cases (Senior-Löken syndrome), either associated with extra-oculorenal abnormalities in six cases (bones, liver, neurology). Twelve older children had a normal examination. Twenty-three children had a normal clinical examination, but non evolutive alterations of ERG.

Adolescent↗
PubMed1986

[Familial cardiomyopathy caused by carnitine deficiency].

The authors report a familial case of carnitine insufficiency presenting in two out of seven children as a severe, isolated, hypertrophic and hypokinetic cardiomyopathy. The etiology was confirmed by histological study and measurement of carnitine concentrations in the blood and muscle. The evolution was spectacular with specific therapy. Left ventricular hypokinesia regressed completely within 18 months (fractional fibre shortening increased from 10 to 33% and the SCI from 26 to 55% in the more severe of the two cases). Hypertrophy and dilatation decreased significantly. This is a so-called intermediary form of carnitine insufficiency and very unusual because of the isolated cardiac involvement. These cases underline the value of systematic muscle biopsy with measurement of carnitine concentrations in the investigation of all cases of supposed primary cardiomyopathy, especially as a rapid improvement can be obtained by specific replacement therapy.

Adolescent↗
PubMed1985

Quantitative morphology of the panda brain in comparison with the brains of the raccoon and the bear.

The quantitative development of brain and brain components with respect to body-size is discussed comparatively for the Chinese Giant Panda, the Canadian Raccoon and the American Black Bear. The panda ranks highest in encephalization as well as in relative volumes of neocortex, cerebellum and six other parts. The raccoon exhibits the strongest development of olfactory elements. The bear stays below the other species, showing but a single index that is superior to the corresponding index in one of them only. These results must be considered within the context of recent debates on the systematic position of the panda. This animal appears to have followed a partly independent evolutionary pathway, although it seems to stand somewhat closer to the raccoon than to the bear, contrary to other views. New comparative eco-ethological studies of the three species, as a complement to our neuromorphological approach, would certainly clarify the status reached by the panda at the end of its long and lonely evolution.

Animals↗
PubMed1996

Molecular evolution of nitrate reductase genes.

To understand the evolutionary mechanisms and relationships of nitrate reductases (NRs), the nucleotide sequences encoding 19 nitrate reductase (NR) genes from 16 species of fungi, algae, and higher plants were analyzed. The NR genes examined show substantial sequence similarity, particularly within functional domains, and large variations in GC content at the third codon position and intron number. The intron positions were different between the fungi and plants, but conserved within these groups. The overall and nonsynonymous substitution rates among fungi, algae, and higher plants were estimated to be 4.33 x 10(-10) and 3.29 x 10(-10) substitutions per site per year. The three functional domains of NR genes evolved at about one-third of the rate of the N-terminal and the two hinge regions connecting the functional domains. Relative rate tests suggested that the nonsynonymous substitution rates were constant among different lineages, while the overall nucleotide substitution rates varied between some lineages. The phylogenetic trees based on NR genes correspond well with the phylogeny of the organisms determined from systematics and other molecular studies. Based on the nonsynonymous substitution rate, the divergence time of monocots and dicots was estimated to be about 340 Myr when the fungi-plant or algae-higher plant divergence times were used as reference points and 191 Myr when the rice-barley divergence time was used as a reference point. These two estimates are consistent with other estimates of divergence times based on these reference points. The lack of consistency between these two values appears to be due to the uncertainty of the reference times.

Base Composition↗
PubMed1994

Evolution of genetic information flow from the viewpoint of protein sequence similarity.

As a course of inquiry into the evolution of genetic information flow, similarity relations of amino acid sequences between the proteins involved in translation, transcription and replication are investigated. The sequence data of these proteins are mostly accumulated from Escherichia coli, and the present investigation is carried out mainly on this organism by the FASTP program. This result reveals an interesting similarity linkage extending from ribosomal proteins to the proteins participating in translational elongation process and to the proteins in transcription and replication. Although the ribosomal proteins are of relatively short polypeptide chains, our systematic comparison between these proteins finds many similarity relations, being more than 100 in terms of "overlap", reducing them to about 14 elementary ribosomal proteins from which other ribosomal proteins would have diverged. Moreover, the proteins involved in translation, transcription and replication contain the regions similar to the elementary ribosomal proteins. In particular, some initiation and elongation factors in translation process are assigned to be similar to the elementary ribosomal proteins almost over the whole regions. To such an elongation factor Tu, the alpha and sigma 70 subunits of RNA polymerase and primase also show similarity in the wider regions than the individual ribosomal proteins, and they are shown to be fundamental for the similarity linkage extending to the other polypeptide chains involved in transcription and replication processes, although the latter polypeptide chains contain regions not similar to any ribosomal protein. This divergence pattern of similarity relations strongly suggests that the proteins involved in the contemporary genetic information flow DNA-->RNA-->protein have evolved from some elementary ribosomal proteins, first by gene fusion, in a primitive organism of the RNA-protein world, and then by the addition of the mechanism of domain shuffling from other genes in the DNA-RNA-protein world.

Amino Acid Sequence↗
PubMed2005

Tachykinin peptides and receptors: putting amphibians into perspective.

The tachykinins form one of the largest peptide families in nature. In this review, we describe the comparative features of the tachykinin peptides and their receptors, focusing particularly on amphibians. We also summarize our systematic studies of the localization, characteristics, and actions of bufokinin, a toad substance P-related peptide, in its species of origin. In addition, we discuss the establishment of multiple isoforms of the NK1-like receptor in the toad, and their structure, pharmacology and tissue distributions. We conclude that tachykinin peptides and receptors are well conserved in terms of their structures, physiological functions and coupling mechanisms during tetrapod evolution.

Amino Acid Sequence↗
PubMed1999

Sterile nodular dermatitis in dogs.

The types of canine sterile nodular dermatitis discussed in this article have in common the clinical presentation of nodules or plaques; however, they differ in many aspects such as breed predilection, distribution and evolution of cutaneous lesions, systemic involvement, response to therapy, and prognosis. The definitive diagnosis should be based on multiple skin biopsy results. Other ancillary tests may be indicated in cases of systemic involvement. In addition, serum alpha1 antitrypsin can be measured to demonstrate the association between nodular panniculitis and serum alpha1 antitrypsin deficiency. A better understanding of the etiopathogenesis of each of these interesting skin conditions necessitates extensive and systematic diagnostic approaches.

Animals↗
PubMed2003

A Y chromosome census of the British Isles.

The degree of population replacement in the British Isles associated with cultural changes has been extensively debated. Recent work has demonstrated that comparisons of genetic variation in the British Isles and on the European Continent can illuminate specific demographic processes in the history of the British Isles. For example, Wilson et al. used the similarity of Basque and Celtic Y chromosomes to argue for genetic continuity from the Upper Palaeolithic to the present in the paternal history of these populations (see also ). Differences in the Y chromosome composition of these groups also suggested genetic signatures of Norwegian influence in the Orkney Islands north of the Scottish mainland, an important center of Viking activities between 800 and 1300 A.D. More recently, Weale et al. argued for substantial Anglo-Saxon male migration into central England based on the analysis of eight British sample sets collected on an east-west transect across England and Wales. To provide a more complete assessment of the paternal genetic history of the British Isles, we have compared the Y chromosome composition of multiple geographically distant British sample sets with collections from Norway (two sites), Denmark, and Germany and with collections from central Ireland, representing, respectively, the putative invading and the indigenous populations. By analyzing 1772 Y chromosomes from 25 predominantly small urban locations, we found that different parts of the British Isles have sharply different paternal histories; the degree of population replacement and genetic continuity shows systematic variation across the sampled areas.

Chromosomes, Human, Y↗
PubMed2001

Structural analysis of free and enzyme-bound amaranth alpha-amylase inhibitor: classification within the knottin fold superfamily and analysis of its functional flexibility.

The three-dimensional structure of the amaranth alpha-amylase inhibitor (AAI) adopts a knottin fold of abcabc topology. Upon binding to alpha-amylase, it adopts a more compact conformation characterized by an increased number of intramolecular hydrogen bonds, a decreased volume and in addition a trans to cis isomerization of Pro20. A systematic analysis of the 3-D structural databanks revealed that similar proteins and domains share with AAI the characteristic presence of proline residues, many of which are in a cis backbone conformation. As these proteins fulfil a variety of functional roles and are expressed in very different organisms, we conclude that the structure of the knottin fold, including the propensity of the cis bond, are the result of convergent evolution.

Algorithms↗
PubMedDate not supplied

[Diagnostic and therapeutic approaches in oculomotor paralyses].

OBJECTIVES: We wish to unify current criteria regarding oculomotor paralysis (POM). Based on our experience, we have designed a diagnostic-therapeutic protocol which permits an early approach, especially since botulinum toxin has been used for treatment. DEVELOPMENT: To make things easier to understand, we start with the concept of POM, including the physiopathogenic description of phenomena secondary to eye movements. Then we consider the aetiological-topographical incidence and assess the overall causes of POM and the relative frequency of the involvement of the different cranial oculomotor nerves. Finally, we consider each cranial nerve more fully from two different angles: the aetiologic-topographic diagnosis and therapeutic attitudes. CONCLUSIONS: The current approach to POM should include a systematic study to classify the disorder as isolated, associated with other neurological causes or of some other type (metabolic, auto-immune, etc). Satisfactory early treatment should include consideration of infilbration with botulinum toxin in all paresis or paralysis presenting with contractures. In cases of total paralysis the contractures may occur within a week of onset of the condition. In partial paralyses close follow-up of three parameters evolution of the degree of ocular deviation, limitation of movement and exploration of passive movements makes it possible to determine the best moment to treat the contracture by injection of botulinum toxin: This treatment resolves or improves the diplopia, with recovery of oculomotor equilibrium, when it is given during the acute phase.

Adolescent↗
PubMed1979

[Corticosteroid-sensitive chemical diabetes in Horton's disease].

We report 5 cases of temporal arteritis associated with a diabetes whose good evolution under corticotherapy suggests a common pathogenesis. Several hypotheses can be formulated to explain the origin of the glycemic abnormality and to understand the way corticotherapy is effective. A moderate posology could at first have a hyperplasic effect on the insulin-secreting cells, and later on a favorable action on the vascular lesion and on an immunological disorder. Any definitive conclusion cannot be evolved yet. Only a more systematical study of the glycoregulation's abnormalities in the temporal arteritis will enable to answer the many remaining questions.

Adrenal Cortex Hormones↗
PubMed2006

A priori resolution of the intermediate spectra in the bacteriorhodopsin photocycle: the time evolution of the L spectrum revealed.

Resolution of the spectra of the intermediates in the photocycle of wild-type bacteriorhodopsin (BR) was achieved by singular value decomposition with exponential-fit-assisted self-modeling (SVD-EFASM) treatment of multichannel difference spectra measured at 5 degrees C during the course of the photocycle. New is the finding that two spectrally distinct L intermediates, L(1) and L(2), form sequentially. Our conclusion is that the photocycle is more complex than most published schemes. The dissection of the spectrally different L forms eliminates stoichiometric discrepancies usually appearing as systematically varying total intermediate concentrations before the onset of BR recovery. In addition, our analysis reveals that the red tails in the spectra of K and L(1) are more substantial than those of L(2) and BR. We suggest that these subtle differences in the shapes of the spectra reflect torsional and/or environmental differences in the retinyl chromophore.

Bacteriorhodopsins↗
PubMed1996

Isotopic constraints on the age and early differentiation of the Earth.

The Earth's age and early differentiation history are re-evaluated using updated isotopic constraints. From the most primitive terrestrial Pb isotopic compositions found at Isua Greenland, and the Pilbara of Western Australia, combined with precise geochronology of these localities, an age 4.49 +/- 0.02 Ga is obtained. This is interpreted as the mean age of core formation as U/Pb is fractionated due to sequestering of Pb into the Earth's core. The long-lived Rb-Sr isotopic system provides constraints on the time interval for the accretion of the Earth as Rb underwent significant depletion by volatile loss during accretion of the Earth or its precursor planetesimals. A primitive measured 87Sr/86Sr initial ratio of 0.700502 +/- 10 has been obtained for an early Archean (3.46 Ga) barite from the Pilbara Block of Western Australia. Using conservative models for the evolution of Rb/Sr in the early Archean mantle allows an estimate to be placed on the Earth's initial Sr ratio at approximately 4.50 Ga, of 0.69940 +/- 10. This is significantly higher than that measured for the Moon (0.69900 +/- 2) or in the achondrite, Angra dos Reis (0.69894 +/- 2) and for a Rb/Sr ratio of approximately 1/2 of chondrites corresponds to a mean age for accretion of the Earth of 4.48 + /- 0.04 Ga. The now extinct 146Sm-142Nd (T1/2(146)=103 l0(6)yrs) combined with the long-lived 147Sm-143Nd isotopic systematics can also be used to provide limits on the time of early differentiation of the Earth. High precision analyses of the oldest (3.8-3.9 Ga) Archean gneisses from Greenland (Amitsoq and Akilia gneisses), and Canada (Acasta gneiss) do not show measurable (> +/- l0ppm) variations of 142Nd, in contrast to the 33 ppm 142Nd excess reported for an Archean sample. The general lack of 142Nd variations, combined with the presence of highly positive epsilon 143 values (+4.0) at 3.9 Ga, indicates that the record of large-scale Sm/Nd fractionation events was not preserved in the early-Earth from 4.56 Ga to approximately 4.3 Ga. This is consistent with large-scale planetary re-homogenisation during ongoing accretion of the Earth. The lack of isotopic anomalies in short-lived decay systems, together with the Pb and Sr isotopic constraints is thus consistent with core formation and accretion of the Earth occurring over an approximately 100 Ma interval following the formation of meteorites at 4.56 Ga.

Earth, Planet↗
PubMed2000

Evolution of the human hand: approaches to acquiring, analysing and interpreting the anatomical evidence.

The discovery of fossil hand bones from an early human ancestor at Olduvai Gorge in 1960, at the same level as primitive stone tools, generated a debate about the role of tools in the evolution of the human hand that has raged to the present day. Could the Olduvai hand have made the tools? Did the human hand evolve as an adaptation to tool making and tool use? The debate has been fueled by anatomical studies comparing living and fossil human and nonhuman primate hands, and by experimental observations. These have assessed the relative abilities of apes and humans to manufacture the Oldowan tools, but consensus has been hampered by disagreements about how to translate experimental data from living species into quantitative models for predicting the performance of fossil hands. Such models are now beginning to take shape as new techniques are applied to the capture, management and analysis of data on kinetic and kinematic variables ranging from hand joint structure, muscle mechanics, and the distribution and density of bone to joint movements and muscle recruitment during manipulative behaviour. The systematic comparative studies are highlighting a functional complex of features in the human hand facilitating a distinctive repertoire of grips that are apparently more effective for stone tool making than grips characterising various nonhuman primate species. The new techniques are identifying skeletal variables whose form may provide clues to the potential of fossil hominid hands for one-handed firm precision grips and fine precision manoeuvering movements, both of which are essential for habitual and effective tool making and tool use.

Animals↗
PubMed1993

Identification of four novel mutations in the COL4A5 gene of patients with Alport syndrome.

The type IV collagen alpha 5 chain (COL4A5) genes of patients with Alport syndrome were tested for major gene rearrangements by Southern blot analysis, using COL4A5 cDNA clones as probes. In addition, individual exons were screened for small mutations by single-strand conformation polymorphism (SSCP) analysis. Four new COL4A5 mutations were detected. A duplication of the nine most 3' located nucleotides of exon 49 and the first nucleotide of intron 49 was identified in the COL4A5 gene of one patient. Two patients displayed single base substitutions leading to, respectively, a proline to threonine and an arginine to glutamine substitution in the C-terminal end. Both substitutions involve amino acids conserved through evolution. In COL4A5 intron 41 a mutation changing the splice acceptor site from AG to AA was identified. All mutations cosegregate with the clinical phenotype of Alport syndrome in affected family members. In a control population of 50 individuals tested by PCR-SSCP these mutations were never identified. Together with two mutations reported previously, a total of six mutations were found in 26 patients with Alport syndrome (23%) after systematic screening of about 30% of the COL4A5 coding region. The clinical features of these six patients are described in detail.

Amino Acid Sequence↗
PubMed2005

Ancient gene duplications and the root(s) of the tree of life.

Tracing organismal histories on the timescale of the tree of life remains one of the challenging tasks in evolutionary biology. The hotly debated questions include the evolutionary relationship between the three domains of life (e.g., which of the three domains are sister domains, are the domains para-, poly-, or monophyletic) and the location of the root within the universal tree of life. For the latter, many different points of view have been considered but so far no consensus has been reached. The only widely accepted rationale to root the universal tree of life is to use anciently duplicated paralogous genes that are present in all three domains of life. To date only few anciently duplicated gene families useful for phylogenetic reconstruction have been identified. Here we present results from a systematic search for ancient gene duplications using twelve representative, completely sequenced, archaeal and bacterial genomes. Phylogenetic analyses of identified cases show that the majority of datasets support a root between Archaea and Bacteria; however, some datasets support alternative hypotheses, and all of them suffer from a lack of strong phylogenetic signal. The results are discussed with respect to the impact of horizontal gene transfer on the ability to reconstruct organismal evolution. The exchange of genetic information between divergent organisms gives rise to mosaic genomes, where different genes in a genome have different histories. Simulations show that even low rates of horizontal gene transfer dramatically complicate the reconstruction of organismal evolution, and that the different most recent common molecular ancestors likely existed at different times and in different lineages.

Carbamoyl-Phosphate Synthase (Ammonia)↗
PubMed1997

Evolution of delta activity within the nonREM sleep episode: a biphasic hypothesis.

The time course of delta activity within nonREM (NREM) episodes is measured for 24 healthy subjects with normal REM latencies. The first two NREM episodes in particular, show two very clearly separated peaks for about 35% of the subjects. Another 25% show two less well separated peaks. These double peak patterns are also prevalent in the literature, but there has been a tendency to dismiss them as a skipped REM effect. They are, however, still evident even when the data are averaged over the 24 subjects, indicating a systematic phenomenon. These averaged data are well fitted by an analytic function given by the sum of two consecutive overlapping Gaussian curves. The well-behaved residuals also, are an indication that a biphasic model of this kind is statistically appropriate. The model proposed is simple, with parameters related to physiological phenomena, and it suggests that there may be an underlying process with delta waves emanating from two separate signal sources. Recent neurophysiological findings suggest that delta oscillations are generated both in the thalamus and in the cortex and show that excessive synchronization of slow oscillations may lead to seizures. Hence the speculation that the biphasic process may emanate from cortical and thalamic sources and be protective in the sense that it permits smaller delta amplitudes at each source while retaining the integral delta energy necessary to satisfy sleep pressure. It is significant that the two peaks are most evident in the first two NREM episodes where delta power is high.

Adult↗