Spongiform Degeneration in mahoganoid Mutant Mice He, Lin; Lu, Xin-Yun; Jolly, Aaron F. ...
Science (American Association for the Advancement of Science),
01/2003, Letnik:
299, Številka:
5607
Journal Article
Recenzirano
mahoganoid is a mouse coat-color mutation whose pigmentary phenotype and genetic interactions resemble those of Attractin (Atrn). Atrn mutations also cause spongiform neurodegeneration. Here, we show ...that a null mutation for mahoganoid causes a similar age-dependent neuropathology that includes many features of prion diseases but without accumulation of protease-resistant prion protein. The gene mutated in mahoganoid encodes a RING-containing protein with E3 ubiquitin ligase activity in vitro. Similarities in phenotype, expression, and genetic interactions suggest that mahoganoid and Atrn genes are part of a conserved pathway for regulated protein turnover whose function is essential for neuronal viability.
To evaluate the impact of a theory-based health education intervention on awareness of prostate cancer and intention to screen among men in Western Jamaica.
One hundred and eighty-eight men attending ...outpatient clinics in a hospital in Western Jamaica completed an interviewer-administered pretest survey. Following the pretest, participants received a health education intervention related to prostate cancer and an immediate post-test survey
There were statistically significant increases in the percentage of correct responses between the pretest and post-test (p < 0.05). The greatest improvement was among items measuring knowledge of prostate cancer screening tests. Participants moved across the Stages of Change theoretical constructs indicating intention to screen.
The sample was receptive to information about prostate cancer and the use of a theory-based educational intervention positively influenced knowledge of prostate cancer risk factors, symptoms, and types of screenings.
This theory-based patient education programme can be replicated to promote awareness of prostate cancer and informed screening methods including potential risk associated with screening behaviours.
Habitat alteration has been implicated in driving hybridization between the sympatric migratory shads
Alosa alosa
and
Alosa fallax
. Morphological and molecular evidence is consistent with ...hybridization across the overlapping range of these species, but the temporal extent of hybrid occurrence and genetic consequences for populations have not been explored. Using eight nuclear microsatellite loci and samples collected between 1989 and 2008 in the Solway Firth (UK), we genetically identified hybrids, studied temporal changes in their frequency, and explored changes in allele frequencies of parental populations. These molecular data confirmed the hybrid status of individuals identified using morphology (number of rakers on the outer gill arch), and enabled separation of hybrids from purebred individuals. Mitochondrial
cytochrome
-
b
sequencing revealed the presence of two haplogroups, each predominantly occurring in one species. Heterospecific haplotypes were found in 22.3 and 12.8% of
A. alosa
and
A. fallax
individuals, respectively, consistent with backcrossing and suggesting that hybrids are fertile. On average, microsatellite-identified hybrids comprised 12.7% of all samples, but when individuals with cytonuclear discordance were also considered introgressed on average 25.4% of individuals were of hybrid ancestry. Overall, allelic richness remained largely unchanged within species, but there were declines in the inbreeding coefficient (
F
IS
) of both species and episodes of significant temporal allelic frequency change. Hybrids sampled between 2004 and 2008 showed no evidence of lower fecundity relative to purebred individuals. Together, results suggest that hybridization between shad species in northern Europe is prevalent, and has been ongoing over at least two decades. The challenge is now to understand the extent to which observed patterns are linked to immigration from other populations, and the mechanisms that have prevented species collapse despite apparent hybrid fertility and longstanding introgression of neutral markers.
A goal of phylogeography is to relate patterns of genetic differentiation to potential historical geographic isolating events. Quaternary glaciations, particularly the one culminating in the Last ...Glacial Maximum ~21 ka (thousands of years ago), greatly affected the distributions and population sizes of temperate marine species as their ranges retreated southward to escape ice sheets. Traditional genetic models of glacial refugia and routes of recolonization include these predictions: low genetic deversity in formerly glaciated areas, with a small number of alleles/haplotypes dominating disproportionately large areas, and high diversity including "private" alleles in glacial refugia. In the Northern Hemisphere, low diversity in the north and high diversity in the south are expected. This simple model does not account for the possibility of populations surviving in relatively small northern periglacial refugia. If these periglacial populations experienced extreme bottlenecks, they could have the low genetic diversity expected in recolonized areas with no refugia, but should have more endemic diversity (private alleles) than recently recolonized areas. This review examines evidence of putative glacial refugia for eight benthic marine taxa in the temperate North Atlantic. All data sets were reanalyzed to allow direct comparisons between geographic patterns of genetic diversity and distribution of particular clades and haplotypes including private alleles. We contend that for marine organisms the genetic signatures of northern periglacial and southern refugia can be distinguished from one another. There is evidence for several periglacial refugia in northern latitudes, giving credence to recent climatic reconstructions with less extensive glaciation.
Magnetorheological (MR) fluids represent a class of smart materials whose rheological properties change in response to the application of a magnetic field. These fluids typically consist of small ...(μm) magnetizable particles dispersed in a nonmagnetic carrier fluid that generally contains additives such as surfactants and antiwear agents 1. Due to such additives, there is an outer nonmagnetic layer on the particles that keeps them from touching. The goal of this paper is to study the effective magnetic behavior of an MR composite as a function of the interparticle distance. To this end, we present and employ a model for the effective magnetic properties of MR fluids with periodic microstructure that is based on the theory of homogenization. Finally, we discuss an interpolating formula for the effective permeability of MR fluids as an extension of the work of Keller 2 and Doyle 3.
Anemia has been associated with adverse outcomes in patients with acute coronary syndromes (ACS). However, the underlying pathophysiologic mechanisms have not been well elucidated. We sought to ...determine the independent relation between the hemoglobin level and recurrent ischemia in patients with non–ST-segment elevation ACS using continuous electrocardiographic monitoring. In the Integrilin and Enoxaparin Randomized Assessment of Acute Coronary Syndrome Treatment (INTERACT) trial, 746 patients presenting with non–ST-segment elevation ACS underwent continuous ST-segment monitoring for 48 hours. The data were analyzed independently at a core laboratory. We stratified the study population according to their hemoglobin level on presentation. The primary outcome of the study was recurrent ischemia, defined as ST-segment shifts on continuous electrocardiographic monitoring. Of the 705 patients with analyzable data, 64 had a baseline hemoglobin level <120 g/L, 259 had a level of 120 to 139 g/L, 315 had a level of 140 to 159 g/L, and 67 had a level >160 g/L. The corresponding rates of recurrent ischemia were 39.1%, 22.0%, 15.6%, and 11.9% (p for trend <0.001). A lower hemoglobin level was associated with advanced age, co-morbidities, and a higher GRACE risk score. In multivariable analysis adjusting for these confounders, lower hemoglobin levels retained a significant independent association with recurrent ischemia (p for trend = 0.004). In conclusion, a lower hemoglobin level at presentation was independently associated with recurrent ischemia detected by continuous electrocardiographic monitoring in the setting of non–ST-segment elevation ACS. This suggests that anemia might predispose patients to recurrent ischemia, which could be an important underlying mediator of worse outcomes in patients with lower hemoglobin levels.
According to a recent demographic survey, the population structure of Pectinaria koreni might fit a source–sink metapopulation model at least at a regional scale. Spatial and temporal genetic ...structure of the populations present in the Baie de Seine (eastern Baie de Seine and Baie des Veys) was assessed using four highly polymorphic microsatellite loci which have revealed strong intra-locality genetic diversity. In the eastern Baie de Seine, both temporal (1994–1996) and spatial (1994) genetic differentiation were relatively low but significantly different from zero despite a 15-day dispersing larval stage. Such structures may be explained by the settlement of larvae from different gene pools and differing recruitment histories among sites within the eastern Baie de Seine. At a larger scale, similar levels of spatial differentiation were observed in 1999 between the eastern Baie de Seine and the Baie des Veys. The lack of any significant differences in gene diversity and allelic richness rules out a source–sink functioning at the scale of our study. The present paper provides further knowledge on the population dynamics of a univoltine species and its persistence in a highly dispersive environment via a shifting spatial mosaic.
Karyotypes for several East Pacific Rise hydrothermal vent invertebrates are described here for the first time: the vestimentiferans Riftia pachyptila and Oasisia alvinae, the alvinellid polychaetes ...Alvinella pompejana, A. caudata and Paralvinella grasslei, the polynoid polychaetes Branchinotogluma grasslei and Branchipolynoe symmytilida, the serpulid Laminatubus alvini and the mytilid bivalve Bathymodiolus thermophilus. For comparative purposes, the karyotype of the Atlantic vent mussel Bathymodiolus azoricus is also described here for the first time. Each species has its own unique chromosomal characteristics which can be interpreted both in terms of group characteristics and species divergence. From comparisons with published results on other vent species and closely-related coastal species, we identified a positive correlation between chromosome number variation and molecular divergence at two ribosomal ribonucleic acid gene loci (the 18S and 28S rRNA). Whilst the patterns of chromosome divergence we found were generally within the ranges previously reported for these taxonomic groupings, there was an apparent inconsistency in the case of Branchipolynoe symmytilida (EPR) and Branchipolynoe seepensis (MAR), which show a greater degree of divergence at the chromosome level compared with other members of the same genus. Moreover, polychaetes as a whole showed greater variation in the number and structural divergence of chromosomes compared to Mytilids (structural information only). Our findings highlight the great potential for chromosome analysis in future taxonomic and evolutionary studies of the deep-sea vent fauna.
Background
There is a significant unmet need for children’s surgical care in low- and middle-income countries (LMICs). Multidisciplinary collaboration is required to advance the surgical and ...anesthesia care of children’s surgical conditions such as congenital conditions, cancer and injuries. Nonetheless, there are limited examples of this process from LMICs. We describe the development and 3-year outcomes following a 2015 stakeholders’ meeting in Uganda to catalyze multidisciplinary and multi-institutional collaboration.
Methods
The stakeholders’ meeting was a daylong conference held in Kampala with local, regional and international collaborators in attendance. Multiple clinical specialties including surgical subspecialists, pediatric anesthesia, perioperative nursing, pediatric oncology and neonatology were represented. Key thematic areas including infrastructure, training and workforce retention, service delivery, and research and advocacy were addressed, and short-term objectives were agreed upon. We reported the 3-year outcomes following the meeting by thematic area.
Results
The Pediatric Surgical Foundation was developed following the meeting to formalize coordination between institutions. Through international collaborations, operating room capacity has increased. A pediatric general surgery fellowship has expanded at Mulago and Mbarara hospitals supplemented by an international fellowship in multiple disciplines. Coordinated outreach camps have continued to assist with training and service delivery in rural regional hospitals.
Conclusion
Collaborations between disciplines, both within LMICs and with international partners, are required to advance children’s surgery. The unification of stakeholders across clinical disciplines and institutional partnerships can facilitate increased children’s surgical capacity. Such a process may prove useful in other LMICs with a wide range of children’s surgery stakeholders.
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