Results 1 - 10 of 781
Results 1 - 10 of 781. Search took: 0.019 seconds
|Sort by: date | relevance|
[en] The data published over the past 15 years on the search for newer anticonvulsant drugs are generalized. Pyrrolidinedione, quinazolinone, xanthone, hydrazine and thiadiazole derivatives manifesting anticonvulsant activity in model in vivo tests in rodents are considered.
[en] Highlights: • High RoTTV prevalence rates were found in three common murine rodents in China. • A novel genotype of RoTTV designated RoTTV3 was detected in this study. • Shrews (Suncus murinus) probably represent a natural host of RoTTV. Between May 2015 and May 2017, 496 animals (473 murine rodents and 23 house shrews) were captured in six regions of China. A total of 22.8% (113/496) of throat swabs, 29.1% (142/488) of fecal samples and 23.8% (54/227) of serum samples tested positive for rodent torque teno virus 3 (RoTTV3). The positive rate in Rattus norvegicus was higher than the rate in Rattus tanezumi and Rattus losea. Of 23 house shrews, one throat swab and one serum sample were positive for RoTTV3. Ten murine rodents were simultaneously positive for RoTTV3 in throat swab, fecal and serum samples. Phylogenetic analysis showed that the 12 near-full length genomes of RoTTVs sequences obtained in this study represented a novel RoTTV genotype (RoTTV3). In conclusion, high prevalence rates of RoTTV3 were found in three common murine rodents in China, and the RoTTV3 obtained in this study were classified as a novel genotype of RoTTV.
[en] Highlights: • A recombinant protein vaccine to parrot bornavirus was tested in cockatiels. • The vaccine failed to protect birds from infection but did block disease development. • Cyclosporin A treatment of birds also blocked disease development. • We propose that proventricular dilation disease in cockatiels is immune mediated. We have demonstrated that vaccination of cockatiels (Nymphicus hollandicus) with killed parrot bornavirus (PaBV) plus recombinant PaBV-4 nucleoprotein (N) in alum was protective against disease in birds challenged with a virulent bornavirus isolate (PaBV-2). Unvaccinated birds, as well as birds vaccinated after challenge, developed gross and histologic lesions typical of proventricular dilatation disease (PDD). There was no evidence that vaccination either before or after challenge made the infection more severe. Birds vaccinated prior to challenge largely remained free of disease, despite the persistence of the virus in many organs. Similar results were obtained when recombinant N, in alum, was used for vaccination. In some rodent models, Borna disease is immune mediated thus we did an additional study whereby cyclosporine A was administered to unvaccinated birds starting 1 day prior to challenge. This treatment also conferred complete protection from disease, but not infection.
[en] Highlights: • Diverse hepadnaviruses are identified in a broad range of bat species in China. • Some of them were closely related to those previously identified in China. • The viruses from Jiyuan were most closely related to Gabon bat hepadnaviruses. • Newly discovered viruses did not clustered by bat species or geographic location. • Frequent cross-species transmission among different bat species was observed. To better understand the evolution of hepadnaviruses, we sampled bats from Guizhou, Henan and Zhejiang provinces, China, and rodents from Zhejiang province. Genetically diverse hepadnaviruses were identified in a broad range of bat species, with an overall prevalence of 13.3%. In contrast, no rodent hepadnaviruses were identified. The newly discovered bat hepadnaviruses fell into two distinct phylogenetic groups. The viruses within the first group exhibited high diversity, with some closely related to viruses previously identified in Yunnan province. Strikingly, the newly discovered viruses sampled from Jiyuan city in the second phylogenetic group were most closely related to those found in bats from West Africa, suggestive of a long-term association between bats and hepadnaviruses. A co-phylogenetic analysis revealed frequent cross-species transmission among bats from different species, genera, and families. Overall, these data suggest that there are likely few barriers to the cross-species transmission of bat hepadnaviruses.
[en] Acute hypoxia is often induced in rodent tumors during studies of the oxygenation or the therapeutic responses of the tumors. Analyses of data from such experiments generally assume that these processes have no effects. The studies described in this report test several aspects of these assumptions using BA1112 rat rhabdomyosarcomas and EMT6 mouse mammary tumors. Both clamping and asphyxiation appear to be effective in producing hypoxia in the tumors. Induction of artificial hypoxia for the times necessary for irradiation was not toxic to the tumor cells and generally did not alter the growth of unirradiated tumors. Clamping BA1112 tumors for 30 min and removing the clamp just before irradiation altered the tumor cell survival curve and the TCD50. Furthermore, anesthesia and/or restraint (necessary during clamping) have significant effects on tumours and hosts. The data show that the assumptions underlying the use of clamping and N2-asphyxiation to produce hypoxia for short periods in vivo are generally reasonable for BA1112 and EMT6 tumors. (Auth.)
[en] Highlights: • Genomic and phylogenetic characterization of new orthohepevirus. • Expansion of the viral diversity and host orthohepevirus. • First report of orthohepevirus in Cricetidae rodents. The Hepeviridae comprise single-stranded positive-sense RNA viruses classified into two genera, Orthohepevirus and Piscihepevirus. Orthohepeviruses have a wide host range that includes rodents, but previous studies had been restricted to rodents of the Muridae family. In this study, we applied a high-throughput sequencing approach to examine the presence of orthohepeviruses in rodents from São Paulo State, Brazil. We also used RT-PCR to determine the frequency of orthohepeviruses in our sampled population. We identified novel orthohepeviruses in blood samples derived from Necromys lasiurus (1.19%) and Calomys tener (3.66%). Therefore, our results expand the host range and viral diversity of the Hepeviridae family.
[en] From 1995 through 2006, we studied a rodent community in western Colorado, observing weather conditions and their effects on least chipmunk (Tamias minimus) and Hopi chipmunk (T. rufus) populations. There are few studies that have assessed relative abundances of chipmunks over long durations and none have been conducted on least chipmunks or Hopi chipmunks. This study is unique in that it assesses abundances of sympatric populations of these chipmunks over a 12-year period. We captured 116 least chipmunks and 62 Hopi chipmunks during 47,850 trap nights of effort. Results indicated that year-to-year precipitation and temperature fluctuations had little effect on these chipmunk populations. However, the relative abundances of Hopi chipmunks and least chipmunks appear to have an inverse relationship with each other, suggesting the potential for resource competition between these congeners.
[en] The Valles Basin (Catalonia, Spain) is a classical area for the study of the Miocene land mammal faunas and includes one of the densest and most continuous records in Eurasia. Furthermore, it is the type area for the Vallesian European land mammal age. After decades of study a huge amount of bio- and magnetostratigraphic data have been collected, allowing an unprecedented dating accuracy. Here we provide an updated local biostratigraphy for the late Aragonian, Vallesian and Turolian of the Vallès-Penedès Basin. This new biostratigraphic scheme is almost exclusively based on fossil rodents, which are the most abundant and one of the best known mammal orders in the area. Our proposal represents a significant refinement compared to previous attempts and provides a formal diagnosis and description of each zone, as well as clear definition of boundaries and a reference locality and section. The chronology of zone boundaries and main bioevents is based on detailed magnetostratigraphic data. The defined biozones allow for the correlation of the sites without associated magnetostratigraphical data. Finally, the correlation of the Vallès-Penedès local zones with other detailed local biostratigraphies, such as those of the Calatayud-Montalbán and Teruel basins (east-central Spain) is discussed. The sequence and chronology of the main bioevents is roughly comparable, although the rodent succession and the structure of the assemblage show important differences between these areas. (Author)