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991.
We showed previously that Theiler's virus, a neurotropic non-enveloped picornavirus of mouse, traffics from the axon of infected neurons into the surrounding myelin. When this traffic is interrupted, as in the shiverer mouse which bears a mutation in the myelin basic protein gene, the virus is unable to persist in the central nervous system. In the present work, we used the Wld(s) mutant mouse, a strain in which axonal degeneration is considerably slowed down, to show that axon to myelin traffic takes place in the absence of axon degeneration. Our results suggest the existence of a mechanism of transfer of axonal cytoplasm into the myelin which Theiler's virus might exploit to ensure its persistence. 相似文献
992.
Bes-Rastrollo M Sabaté J Gómez-Gracia E Alonso A Martínez JA Martínez-González MA 《Obesity (Silver Spring, Md.)》2007,15(1):107-116
Objective: To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. Research Methods and Procedures: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow‐up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food‐frequency questionnaire. Results: Nine hundred thirty‐seven participants reported a weight gain of ≥5 kg at follow‐up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. Discussion: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain. 相似文献
993.
994.
Manuel Cantos Juana Linán José L. García María García-Linán Miguel A. Domínguez Antonio Troncoso 《Central European Journal of Biology》2007,2(2):297-306
Rhododendron ponticum subsp. baeticum is endemic in the southern region of the Iberian Peninsula. The relict populations of this species are vulnerable, due mainly
to difficult conditions for the establishment of seedlings, resulting in a virtual lack of sexual recruitment. In order to
preserve the surviving populations, in vitro culture methods have been applied for both the sexual and the agamic propagation of the species. The in vitro germination of seeds was high when conducted with Anderson’s medium without plant growth regulators. The self-rooted seedlings
obtained were easily transplanted to outside conditions. The presence of growth regulators in the medium interfered with the
development of the seedlings, causing heavy callus formation. The in vitro growth of explants took place readily in Anderson’s medium plus 0.072 mg L−1 of BA and 0.036 mg L−1 of NAA although the explants did not form roots. Rooting was achieved by the basal dipping of the explants in hydroalcoholic
solutions of 500 mg L−1 IAA during the outside transplanting process. Therefore, the combination of in vitro grown explants together with ex vitro rooting, results in a good method for the agamic propagation of Rhododendron ponticum subsp. baeticum. 相似文献
995.
Wang-Sattler R Blandin S Ning Y Blass C Dolo G Touré YT delle Torre A Lanzaro GC Steinmetz LM Kafatos FC Zheng L 《PloS one》2007,2(11):e1249
Background
Attempts over the last three decades to reconstruct the phylogenetic history of the Anopheles gambiae species complex have been important for developing better strategies to control malaria transmission.Methodology
We used fingerprint genotyping data from 414 field-collected female mosquitoes at 42 microsatellite loci to infer the evolutionary relationships of four species in the A. gambiae complex, the two major malaria vectors A. gambiae sensu stricto (A. gambiae s.s.) and A. arabiensis, as well as two minor vectors, A. merus and A. melas.Principal Findings
We identify six taxonomic units, including a clear separation of West and East Africa A. gambiae s.s. S molecular forms. We show that the phylogenetic relationships vary widely between different genomic regions, thus demonstrating the mosaic nature of the genome of these species. The two major malaria vectors are closely related and closer to A. merus than to A. melas at the genome-wide level, which is also true if only autosomes are considered. However, within the Xag inversion region of the X chromosome, the M and two S molecular forms are most similar to A. merus. Near the X centromere, outside the Xag region, the two S forms are highly dissimilar to the other taxa. Furthermore, our data suggest that the centromeric region of chromosome 3 is a strong discriminator between the major and minor malaria vectors.Conclusions
Although further studies are needed to elucidate the basis of the phylogenetic variation among the different regions of the genome, the preponderance of sympatric admixtures among taxa strongly favor introgression of different genomic regions between species, rather than lineage sorting of ancestral polymorphism, as a possible mechanism. 相似文献996.
Tumor ablation with irreversible electroporation 总被引:1,自引:0,他引:1
Al-Sakere B André F Bernat C Connault E Opolon P Davalos RV Rubinsky B Mir LM 《PloS one》2007,2(11):e1135
We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 micros at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%), in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation. 相似文献
997.
998.
PHILIP S WANG MATTHIAS ANGERMEYER GUILHERME BORGES RONNY BRUFFAERTS WAI TAT CHIU GIOVANNI DE GIROLAMO JOHN FAYYAD OYE GUREJE JOSEP MARIA HARO YUEQIN HUANG RONALD C KESSLER VIVIANE KOVESS DAPHNA LEVINSON YOSHIBUMI NAKANE MARK A OAKLEY BROWN JOHAN H ORMEL JOSé POSADA-VILLA SERGIO AGUILAR-GAXIOLA JORDI ALONSO SING LEE STEVEN HEERINGA BETH-ELLEN PENNELL SOMNATH CHATTERJI T. BEDIRHAN üSTüN 《World psychiatry》2007,6(3):177-185
Data are presented on patterns of failure and delay in making initial treatment
contact after first onset of a mental disorder in 15 countries in the World
Health Organization (WHO)''s World Mental Health (WMH) Surveys. Representative
face-to-face household surveys were conducted among 76,012 respondents aged
18 and older in Belgium, Colombia, France, Germany, Israel, Italy, Japan,
Lebanon, Mexico, the Netherlands, New Zealand, Nigeria, People''s Republic
of China (Beijing and Shanghai), Spain, and the United States. The WHO Composite
International Diagnostic Interview (CIDI) was used to assess lifetime DSM-IV
anxiety, mood, and substance use disorders. Ages of onset for individual disorders
and ages of first treatment contact for each disorder were used to calculate
the extent of failure and delay in initial help seeking. The proportion of
lifetime cases making treatment contact in the year of disorder onset ranged
from 0.8 to 36.4% for anxiety disorders, from 6.0 to 52.1% for mood disorders,
and from 0.9 to 18.6% for substance use disorders. By 50 years, the proportion
of lifetime cases making treatment contact ranged from 15.2 to 95.0% for anxiety
disorders, from 7.9 to 98.6% for mood disorders, and from 19.8 to 86.1% for
substance use disorders. Median delays among cases eventually making contact
ranged from 3.0 to 30.0 years for anxiety disorders, from 1.0 to 14.0 years
for mood disorders, and from 6.0 to 18.0 years for substance use disorders.
Failure and delays in treatment seeking were generally greater in developing
countries, older cohorts, men, and cases with earlier ages of onset. These
results show that failure and delays in initial help seeking are pervasive
problems worldwide. Interventions to ensure prompt initial treatment contacts
are needed to reduce the global burdens and hazards of untreated mental disorders. 相似文献
999.
Interactions between neurons and glial cells are crucial for nervous system development and function in all complex organisms, and many functional, morphological and molecular features of glia are well conserved among species. Here we review studies of the longitudinal glia (LG) in the Drosophila CNS. The LG envelop the neuropil in a membrane sheath, and have features resembling both oligodendrocytes and astrocytes. Because of their unique lineage, morphology and molecular features, the LG provide an excellent model to study the genetic mechanisms underlying glial subtype differentiation and diversity, glial morphogenesis and neuron-glial interactions during development. In addition, they are proving useful in understanding how glial cells maintain ion and neurotransmitter homeostasis and protect neurons from environmental insult. 相似文献
1000.
Brain serine racemase contains pyridoxal phosphate as a prosthetic group and is known to become activated by divalent cations such as Ca(2+) and Mg(2+), as well as by ATP and ADP. In vivo, brain serine racemase is also activated by a multi-PSD-95/discs large/ZO-1 (PDZ) domain glutamate receptor interacting protein (GRIP) that is usually coupled to the GluR2/3 subunits of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid Ca(2+) channel. In the present study, we analysed the mechanisms by which serine racemase becomes activated by GRIP, divalent cations and ATP. We show that binding of PDZ6 of GRIP to serine racemase does not result in increased d-serine production. However, full-length GRIP does augment significantly enzymatic activity. We expressed various GRIP shorter constructs to map down the regions within GRIP that are necessary for serine racemase activation. We observed that, whereas recombinant proteins containing PDZ4-PDZ5-PDZ6 are unable to activate serine racemase, other constructs containing PDZ4-PDZ5-PDZ6-GAP2-PDZ7 significantly augment its activity. Hence, activation of serine racemase by GRIP is not a direct consequence of the translocation towards the calcium channel but rather a likely conformational change induced by GRIP on serine racemase. On the other hand, the observed activation of serine racemase by divalent cations has been assumed to be a side-effect associated with ATP binding, which is known to form a complex with Mg(2+) ions. Because no mammalian serine racemase has yet been crystallized, we used molecular modelling based on yeast and bacterial homologs to demonstrate that the binding sites for Ca(2+), ATP and the PDZ6 domain of GRIP are spatially separated and modulate the enzyme through distinct mechanisms. 相似文献