RESUMO
We establish a heralded interaction between two remotely trapped single (40)Ca(+) ions through the exchange of single photons. In the sender ion, we release single photons with a controlled temporal shape on the P(3/2) to D(5/2) transition and transmit them to the distant receiver ion. Individual absorption events in the receiver ion are detected by quantum jumps. For continuously generated photons, the absorption reduces significantly the lifetime of the long-lived D(5/2) state. For triggered single-photon transmission, we observe a coincidence between the emission at the sender and quantum jump events at the receiver.
RESUMO
Analysis of variation at microsatellite DNA loci is widely used in studies of parentage, linkage and evolutionary history. The utility of microsatellites is primarily due to high levels of allelic diversity, believed to reflect mutation rates orders of magnitude higher than base pair substitutions at single-copy genes. For humans, mice, rats and pigs, microsatellite mutation rates have been estimated at 10(-3)-10(-5). However, a recent study comparing microsatellite variation in humans with non-human primates suggests that microsatellite mutation rates may vary considerably across taxa. We measured mutation rates of 24 microsatellite loci in mutation accumulation lines of Drosophila melanogaster. Surprisingly, only a single mutation was detected after screening 157,680 allele-generations, yielding an estimated average mutation rate per locus of 6.3 x 10(-6), a mutation rate considerably lower than reported for various mammals. We propose that the comparatively low mutation rate is primarily a function of short microsatellite repeat lengths in the D. melanogaster genome.
Assuntos
Drosophila melanogaster/genética , Repetições de Microssatélites/genética , Mutação , Animais , Humanos , Dados de Sequência MolecularRESUMO
OBJECTIVE: High quality demands are being placed on concepts of educational group programmes in medical rehabilitation as well as the related trainer qualifications. A nationwide survey of German medical rehabilitation clinics in 2005 had revealed a need for improving educational practice according to these quality criteria. An updated investigation was performed in 2010 aiming at describing group programmes used in medical rehabilitation. METHOD: 1 473 inpatient and outpatient medical rehabilitation clinics were invited to participate. 908 clinics reported on their training programmes. Data from clinics caring for patients with somatic disorders could be compared to the 2005 survey. Data from clinics for both psychosomatic and substance abuse disorders was collected for the first time in 2010. RESULTS: Overall, psychologists and physicians were reported to be the most frequent conductors of educative programmes. In somatic clinics, psychologists, dieticians and occupational therapists or physiotherapists were the most common conductors. Two-thirds of the institutions reported no training prerequisites for staff members to perform patient education. 80% of the education programmes were categorized post hoc into 3 classes: "generic health education", "disorder-specific patient education", and "psychoeducational group programmes". Almost two-thirds of all programmes were carried out with 8-15 participants, and many used several interactive didactic methods. Programmes conducted in small groups (<8 participants) used significantly more interactive methods than those conducted in larger groups did (>15 participants). Only half of the programmes were manualized. Significantly more interactive methods were used in completely manualized programmes. Only about half of the programmes were evaluated, and only very few evaluation studies were published. The institutions wished additional support by workshops especially concerning qualification of their staff and concerning educational concepts. CONCLUSIONS: A need for further improvement and support exists relative to the training of educators and the development of manuals as well as evaluation and publication of the programmes.
Assuntos
Promoção da Saúde/estatística & dados numéricos , Corpo Clínico/educação , Transtornos Mentais/reabilitação , Educação de Pacientes como Assunto/estatística & dados numéricos , Psicoterapia de Grupo/estatística & dados numéricos , Reabilitação/educação , Reabilitação/estatística & dados numéricos , Adulto , Idoso , Coleta de Dados , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Corpo Clínico/estatística & dados numéricos , Transtornos Mentais/epidemiologia , Pessoa de Meia-Idade , Prevalência , Fatores de RiscoRESUMO
Collinear laser spectroscopy was performed on Ga (Z=31) isotopes at ISOLDE, CERN. A gas-filled linear Paul trap (ISCOOL) was used to extend measurements towards very neutron-rich isotopes (N=36-50). A ground state (g.s.) spin I=1/2 is measured for 73Ga, being near degenerate with a 3/2{-} isomer (75 eVâ²E{ex}â²1 keV). The 79Ga g.s., with I=3/2, is dominated by protons in the πf{5/2} orbital and in 81Ga the 5/2{-} level becomes the g.s. The data are compared to shell-model calculations in the f{5/2}pg{9/2} model space, calling for further theoretical developments and new experiments.
RESUMO
We report the first confirmation of the predicted inversion between the pi2p3/2 and pi1f5/2 nuclear states in the nu(g)9/2 midshell. This was achieved at the ISOLDE facility, by using a combination of in-source laser spectroscopy and collinear laser spectroscopy on the ground states of 71,73,75Cu, which measured the nuclear spin and magnetic moments. The obtained values are mu(71Cu)=+2.2747(8)mu(N), mu(73Cu)=+1.7426(8)mu(N), and mu(75Cu)=+1.0062(13)mu(N) corresponding to spins I=3/2 for 71,73Cu and I=5/2 for 75Cu. The results are in fair agreement with large-scale shell-model calculations.
RESUMO
Recent studies have presented evidence that in vivo obtained gene expression data can be used for carcinogen classification, for instance to differentiate between genotoxic and non-genotoxic carcinogens. However, although primary rat hepatocytes represent a well-established in vitro system for drug metabolism and enzyme induction, they have not yet been systematically optimized for toxicogenomic studies. The latter may be confounded by the fact that cultured hepatocytes show strong spontaneous alterations in gene expression patterns. Therefore, we addressed the following questions: (1) which culture system is optimal, comparing sandwich, Matrigel and 2D cultures, (2) how critical is the impact of culture period on substance-induced alterations in gene expression and (3) do these substance-induced alterations in cultured hepatocytes occur already at in vivo relevant concentrations? For this purpose we analyzed the expression of four genes, namely Abat, Gsk3beta, Myd116 and Sult1a1 that recently have been reported to be influenced by the antihistamine and non-genotoxic carcinogen methapyrilene (MPy). The most reproducible effects of MPy were observed in sandwich cultures. Induction factors of Gsk3beta and Myd116 at 100 microM MPy were 2 and 4 (medians), respectively, whereas expression of Abat and Sult1a1 were inhibited by factors of 7 and 5, respectively. Similar results were observed in hepatocytes maintained for 24 h or 3 weeks in sandwich culture with respect to the influence of MPy on the expression of Abat, Gsk3beta, Myd116 and Sult1a1. To determine whether MPy influences gene expression at in vivo relevant concentrations, 3.5 mg/kg MPy were administered to male Wistar rats intraperitoneally, resulting in plasma concentrations ranging between 1.72 and 0.32 microM 5 and 80 min after injection. Inhibition of Abat and Sult1a1 expression in vitro already occurred at in vivo relevant concentrations of 0.39 microM MPy. Induction of Myd116 was observed at 6.25 microM which is higher but in the same order of magnitude as in vivo relevant concentrations. In conclusion, the presented data strongly suggest that sandwich cultures are most adequate for detection of MPy-induced gene expression alterations and the effect of MPy was detected at in vivo relevant concentrations.
Assuntos
Técnicas de Cultura de Células/métodos , Colágeno/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Laminina/efeitos dos fármacos , Metapirileno/toxicidade , Proteoglicanas/efeitos dos fármacos , Animais , Antígenos de Diferenciação/metabolismo , Arilsulfotransferase/metabolismo , Carcinógenos/toxicidade , Células Cultivadas , Meios de Cultura Livres de Soro , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/enzimologia , Hepatócitos/enzimologia , Hepatócitos/metabolismo , Masculino , Metapirileno/sangue , Proteínas Proto-Oncogênicas/metabolismo , Ratos , Ratos Wistar , Proteínas Repressoras/metabolismo , Fatores de Tempo , ToxicogenéticaRESUMO
A hip joint simulator was developed to analyse the mechanism of loosening of cementless artificial hip cups. The machine induces vibrating motions and asymmetrical tilt shock loadings of the artificial cup. On measuring the primary stability of threaded cups, the simulation tests performed on pelvis substitute models, and animal and human acetabula failed to show any loosening of threaded cups fixed in place with a screw-in torque of more than 10 Nm. Instable cups became loose all the sooner, the lower the preload between the cup and femoral head. This demonstrates the importance of both the screw-in torque of the cup and the training status of the periarticular muscles.
Assuntos
Prótese de Quadril , Fenômenos Biomecânicos , Humanos , Desenho de Prótese , Falha de Prótese , Fatores de RiscoRESUMO
The success of an artificial joint replacement over the long term depends, for the most part, on the optimal positioning of the acetabular cup. We investigated this thought in terms of biomechanical and clinical considerations, and, on the basis of a proposed classification, attempted to ascertain the best possible position. On the basis of our analysis we determined that the ideal position is an angle of 35 degrees, with a tolerance range of 25 degrees to 45 degrees. Here, the load on the polyethylene is low, so that wear and the formation of particles are minimized. This position can readily be achieved surgically with the aid of an auxiliary device and clinically provides the best results in terms of muscular stability, endurance and optimal scoring.
Assuntos
Acetábulo , Prótese de Quadril/classificação , Acetábulo/diagnóstico por imagem , Acetábulo/cirurgia , Fenômenos Biomecânicos , Seguimentos , Humanos , Desenho de Prótese , Falha de Prótese , RadiografiaRESUMO
Although cultivated hepatocytes are widely used in the studies of drug metabolism, their application in toxicogenomics is considered as problematic, because previous studies have reported only little overlap between chemically induced gene expression alterations in liver in vivo and in cultivated hepatocytes. Here, we identified 22 genes that were altered in livers of rats after oral administration of the liver carcinogens aflatoxin B1 (AB1), 2-nitrofluorene (2-NF), methapyrilene (MP) or piperonyl-butoxide (PBO). The functions of the 22 genes have been classified into two groups. Genes related to stress response, DNA repair or metabolism and genes associated with cell proliferation, respectively. Next, rat hepatocyte sandwich cultures were exposed to AB1, 2-NF, MP or PBO for 24h and expression of the above mentioned genes was determined by RT-qPCR. Significant correlations between the degree of gene expression alterations in vivo and in vitro were obtained for the stress, DNA repair and metabolism associated genes at concentrations covering a range from cytotoxic concentrations to non-toxic/in vivo relevant concentrations. In contrast to the stress associated genes, no significant in vivo/in vitro correlation was obtained for the genes associated with cell proliferation. To understand the reason of this discrepancy, we compared replacement proliferation in vivo and in vitro. While hepatocytes in vivo, killed after administration of hepatotoxic compounds, are rapidly replaced by proliferating surviving cells, in vitro no replacement proliferation as evidenced by BrdU incorporation was observed after washing out hepatotoxic concentrations of MP. In conclusion, there is a good correlation between gene expression alterations induced by liver carcinogens in vivo and in cultivated hepatocytes. However, it should be considered that cultivated primary hepatocytes do not show replacement proliferation explaining the in vivo/in vitro discrepancy concerning proliferation associated genes.
Assuntos
Carcinógenos/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Aflatoxina B1/administração & dosagem , Aflatoxina B1/farmacologia , Animais , Carcinógenos/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Fluorenos/administração & dosagem , Fluorenos/farmacologia , Regulação da Expressão Gênica/genética , Hepatócitos/citologia , Masculino , Metapirileno/administração & dosagem , Metapirileno/farmacologia , Butóxido de Piperonila/administração & dosagem , Butóxido de Piperonila/farmacologia , Ratos , Ratos Wistar , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
The polychaete tubeworm Hydroides elegans (Haswell) is a biofouling species with relatively limited larval dispersal. Four highly polymorphic microsatellite loci were used to make inferences about the migration and global population structure of 137 individuals from seven sub-populations located in the Atlantic, Pacific, and Indian Oceans and in the Mediterranean Sea. The results of the genetic analyses suggest minimal population sub-structure (F(st) = 0.09). Estimates of pairwise F(st) and migration rates using the coalescent-based method of MIGRATE suggest that there is little genetic differentiation between certain populations. Variation in relatedness among pairs of populations is consistent with a suite of local and global factors. The most likely explanation for close genetic relatedness among certain populations over such vast distances is the regular and consistent transport of adults and larvae on the hulls and in the ballast water of ships, respectively.
Assuntos
Repetições de Microssatélites/genética , Poliquetos/genética , Poliquetos/fisiologia , Migração Animal , Animais , Filogenia , Dinâmica PopulacionalRESUMO
We isolated 96 dinucleotide repeats with five or more tandemly repeated units from a subgenomic Drosophila subobscura library. The mean repeat unit length of microsatellite clones in D. subobscura is 15, higher than that observed in other Drosophila species. Population variation was assayed in 32-40 chromosomes from Barcelona, Spain, using 18 randomly chosen microsatellite loci. Positive correlation between measures of variation and perfect repeat length measures (mean size, most common, and longest allele) is consistent with a higher mutation rate in loci with longer repeat units. Levels of microsatellite variation measured as variance in repeat number and heterozygosity in D. subobscura were similar to those of Drosophila pseudoobscura and higher than those of Drosophila melanogaster and Drosophila simulans. Our data suggest that higher levels of microsatellite variation, and possibly density, in D. subobscura compared with D. melanogaster are due to both a higher average effective population and a higher intrinsic slippage rate in the former species.
Assuntos
Repetições de Dinucleotídeos/genética , Drosophila/genética , Repetições de Microssatélites/genética , Alelos , Animais , Sequência de Bases , DNA/química , DNA/genética , Drosophila melanogaster/genética , Variação Genética , Biblioteca Genômica , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
We have isolated, characterized and mapped 33 dinucleotide, three trinucleotide and one tetranucleotide repeat loci from the four major chromosomes of Drosophila pseudoobscura. Average inferred repeat unit length of the dinucleotide repeats is 12 repeat units, similar to D. melanogaster. Assays of D. pseudoobscura and populations of its sibling species, D. persimilis, using 10 of these loci show extremely high levels of variation compared with similar studies of dinucleotide repeat variation in D. melanogaster populations. The high levels of variation are consistent with an average mutation rate of approximately 10(-6) per locus per generation and an effective population size of D. pseudoobscura approximately four times larger than that of D. melanogaster. Consistent with allozymes and nucleotide sequence polymorphism, the dinucleotide repeat loci reveal minimal structure across four populations of D. pseudoobscura. Finally, our preliminary recombinational mapping of 24 of these microsatellites suggests that the total recombinational genome size may be larger than previously inferred using morphological mutant markers.
Assuntos
Drosophila/genética , Variação Genética , Repetições de Microssatélites/genética , Animais , Sequência de Bases , Primers do DNA , Especificidade da EspécieRESUMO
Interspecific comparisons of microsatellite loci have repeatedly shown that the loci are longer and more variable in the species from which they are derived (the focal species) than are homologous loci in other (nonfocal) species. There is debate as to whether this is due to directional evolution or to an ascertainment bias during the cloning and locus selection processes. This study tests these hypotheses by performing a reciprocal study. Eighteen perfect dinucleotide microsatellite loci identified from a Drosophila simulans library screen and 18 previously identified in an identical Drosophila melanogaster library screen were used to survey natural populations of each species. No difference between focal and nonfocal species was observed for mean PCR fragment length. However, heterozygosity and number of alleles were significantly higher in the focal species than in the nonfocal species. The most common allele in the Zimbabwe population of both species was sequenced for 31 of the 36 loci. The length of the longest stretch of perfect repeat units is, on average, longer in the focal species than in the non-focal species. There is a positive correlation between the length of the longest stretch of perfect repeats and heterozygosity. The difference in heterozygosity can thus be explained by a reduction in the length of the longest stretch of perfect repeats in the nonfocal species. Furthermore, flanking-sequence length difference was noted between the two species at 58% of the loci sequenced. These data do not support the predictions of the directional-evolution hypothesis; however, consistent with the ascertainment bias hypothesis, the lower variability in nonfocal species is an artifact of the microsatellite cloning and isolation process. Our results also suggest that the magnitude of ascertainment bias for repeat unit length is a function of the microsatellite size distribution in the genomes of different species.
Assuntos
Mapeamento Cromossômico , Drosophila melanogaster/genética , Drosophila/genética , Variação Genética , Repetições de Microssatélites , Modelos Genéticos , Animais , Sequência de Bases , Primers do DNA , Marcadores Genéticos , Biblioteca Genômica , Heterozigoto , Modelos Estatísticos , Reação em Cadeia da Polimerase , Análise de RegressãoRESUMO
Drosophila ananassae is a cosmopolitan species with a geographic range throughout most of the tropical and subtropical regions of the world. Previous studies of DNA sequence polymorphism in three genes has shown evidence of selection affecting broad expanses of the genome in regions with low rates of recombination in geographically local populations in and around India. The studies suggest that extensive physical and genetic maps based on molecular markers, and detailed studies of population structure may provide insight into the degree to which natural selection affects DNA sequence polymorphism across broad regions of chromosomes. We have isolated 85 dinucleotide repeat microsatellite sequences and developed assay conditions for genotyping using PCR. The dinucleotide repeats we isolated are shorter, on average, than those isolated in many other Drosophila species. Levels of genetic variation are high, comparable to Drosophila melanogaster. The levels of variation indicate the effective population size of an Indonesian population of D. ananassae is 58,692 (infinite allele model) and 217,284 (stepwise mutation model), similar to estimates of effective population size for D. melanogaster calculated using dinucleotide repeat microsatellites. The data also show that the Indonesian population is in a rapid expansion phase. Cross-species amplification of the microsatellites in 11 species from the Ananassae, Elegans, Eugracilis and Ficusphila subgroups indicates that the loci may be useful for studies of the sister species, D. pallidosa, but will have limited use for more distantly related species.
Assuntos
Repetições de Dinucleotídeos/genética , Drosophila/genética , Variação Genética , Genética Populacional , Seleção Genética , Alelos , Animais , Sequência de Bases , Primers do DNA , Triagem de Portadores Genéticos , Indonésia , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
We fit a Markov chain model of microsatellite evolution introduced by Kruglyak et al. to data on all di-, tri-, and tetranucleotide repeats in the yeast genome. Our results suggest that many features of the distribution of abundance and length of microsatellites can be explained by this simple model, which incorporates a competition between slippage events and base pair substitutions, with no need to invoke selection or constraints on the lengths. Our results provide some new information on slippage rates for individual repeat motifs, which suggest that AT-rich trinucleotide repeats have higher slippage rates. As our model predicts, we found that many repeats were adjacent to shorter repeats of the same motif. However, we also found a significant tendency of microsatellites of different motifs to cluster.
Assuntos
Genoma Fúngico , Repetições de Microssatélites/genética , Saccharomyces cerevisiae/genética , Sequência de Bases , DNA Fúngico/genética , Repetições de Dinucleotídeos , Cadeias de Markov , Modelos Genéticos , Mutação Puntual , Repetições de TrinucleotídeosRESUMO
We describe and test a Markov chain model of microsatellite evolution that can explain the different distributions of microsatellite lengths across different organisms and repeat motifs. Two key features of this model are the dependence of mutation rates on microsatellite length and a mutation process that includes both strand slippage and point mutation events. We compute the stationary distribution of allele lengths under this model and use it to fit DNA data for di-, tri-, and tetranucleotide repeats in humans, mice, fruit flies, and yeast. The best fit results lead to slippage rate estimates that are highest in mice, followed by humans, then yeast, and then fruit flies. Within each organism, the estimates are highest in di-, then tri-, and then tetranucleotide repeats. Our estimates are consistent with experimentally determined mutation rates from other studies. The results suggest that the different length distributions among organisms and repeat motifs can be explained by a simple difference in slippage rates and that selective constraints on length need not be imposed.
Assuntos
Repetições de Microssatélites , Mutação Puntual , Animais , Evolução Molecular , Humanos , Cadeias de Markov , Modelos GenéticosRESUMO
Levels of nucleotide polymorphism in the Drosophila melanogaster genome are correlated with rates of recombination. This relationship may be due to hitchhiking of advantageous mutations (selective sweeps) or to continual removal of deleterious mutations from the genome (background selection). One test of the relative contributions of selective sweeps and background selection to the observed levels of variation in the genome of D. melanogaster is to compare levels of nucleotide variability (with a mutation rate on the order of 10(-9) per nucleotide per generation) with more rapidly evolving DNA loci such as microsatellites. This test depends critically on details of the mutational process of microsatellites. In this paper, we summarize our studies of microsatellite characteristics and mutation rates in D. melanogaster. We find that D. melanogaster microsatellites are short and have a mutation rate (6.5 x 10(-6) per locus per generation) several orders of magnitude lower than mammals studied to date. We further show that genetic variation at 18 dinucleotide repeat microsatellites in a population of D. melanogaster from Maryland is correlated with regional rates of recombination. These and other microsatellite data suggest that both background selection and selective sweeps may contribute to the correlation between DNA sequence variation and recombination in Drosophila.
Assuntos
Drosophila melanogaster/genética , Drosophila/genética , Evolução Molecular , Repetições de Microssatélites , Mutação , Polimorfismo Genético , Alelos , Animais , Sequência de Bases , Variação Genética , Dados de Sequência Molecular , Recombinação Genética , Alinhamento de Sequência , Homologia de Sequência do Ácido NucleicoRESUMO
We report the results of a comprehensive search of Drosophila melanogaster DNA sequences in GenBank for di-, tri-, and tetranucleotide repeats of more than four repeat units, and a DNA library screen for dinucleotide repeats. Dinucleotide repeats are more abundant (66%) than tri- (30%) or tetranucleotide (4%) repeats. We estimate that 1917 dinucleotide repeats with 10 or more repeat units are present in the euchromatic D. melanogaster genome and, on average, they occur once every 60 kb. Relative to many other animals, dinucleotide repeats in D. melanogaster are short. Tri- and tetranucleotide repeats have even fewer repeat units on average than dinucleotide repeats. Our WorldWide Web site (http://www.bio.cornell.edu/genetics/aquadro/+ ++aquadro.html) posts the complete list of 1298 microsatellites (> or = five repeat units) identified from the GenBank search. We also summarize assay conditions for 70 D. melanogaster microsatellites characterized in previous studies and an additional 56 newly characterized markers.
Assuntos
Primers do DNA , Bases de Dados Factuais , Drosophila melanogaster/genética , Repetições de Microssatélites , Animais , Mapeamento Cromossômico , Frequência do Gene , Variação GenéticaRESUMO
In a recent study, we reported that the combined average mutation rate of 10 di-, 6 tri-, and 8 tetranucleotide repeats in Drosophila melanogaster was 6.3 x 10(-6) mutations per locus per generation, a rate substantially below that of microsatellite repeat units in mammals studied to date (range = 10(-2)-10(-5) per locus per generation). To obtain a more precise estimate of mutation rate for dinucleotide repeat motifs alone, we assayed 39 new dinucleotide repeat microsatellite loci in the mutation accumulation lines from our earlier study. Our estimate of mutation rate for a total of 49 dinucleotide repeats is 9.3 x 10(-6) per locus per generation, only slightly higher than the estimate from our earlier study. We also estimated the relative difference in microsatellite mutation rate among di-, tri-, and tetranucleotide repeats in the genome of D. melanogaster using a method based on population variation, and we found that tri- and tetranucleotide repeats mutate at rates 6.4 and 8.4 times slower than that of dinucleotide repeats, respectively. The slower mutation rates of tri- and tetranucleotide repeats appear to be associated with a relatively short repeat unit length of these repeat motifs in the genome of D. melanogaster. A positive correlation between repeat unit length and allelic variation suggests that mutation rate increases as the repeat unit lengths of microsatellites increase.