617 research outputs found
Connectivity-based parcellation of the thalamus explains specific cognitive and behavioural symptoms in patients with bilateral thalamic infarct
A novel approach based on diffusion tractography was used here to characterise the cortico-thalamic connectivity in two patients, both presenting with an isolated bilateral infarct in the thalamus, but exhibiting partially different cognitive and behavioural profiles. Both patients (G.P. and R.F.) had a pervasive deficit in episodic memory, but only one of them (R.F.) suffered also from a dysexecutive syndrome. Both patients had an MRI scan at 3T, including a T1-weighted volume. Their lesions were manually segmented. T1-volumes were normalised to standard space, and the same transformations were applied to the lesion masks. Nineteen healthy controls underwent a diffusion-tensor imaging (DTI) scan. Their DTI data were normalised to standard space and averaged. An atlas of Brodmann areas was used to parcellate the prefrontal cortex. Probabilistic tractography was used to assess the probability of connection between each voxel of the thalamus and a set of prefrontal areas. The resulting map of corticothalamic connections was superimposed onto the patients' lesion masks, to assess whether the location of the thalamic lesions in R.F. (but not in G. P.) implied connections with prefrontal areas involved in dysexecutive syndromes. In G.P., the lesion fell within areas of the thalamus poorly connected with prefrontal areas, showing only a modest probability of connection with the anterior cingulate cortex (ACC). Conversely, R.F.'s lesion fell within thalamic areas extensively connected with the ACC bilaterally, with the right dorsolateral prefrontal cortex, and with the left supplementary motor area. Despite a similar, bilateral involvement of the thalamus, the use of connectivity-based segmentation clarified that R.F.'s lesions only were located within nuclei highly connected with the prefrontal cortical areas, thus explaining the patient's frontal syndrome. This study confirms that DTI tractography is a useful tool to examine in vivo the effect of focal lesions on interconnectivity brain patterns
Phylogenetic Codivergence Supports Coevolution of Mimetic Heliconius Butterflies
The unpalatable and warning-patterned butterflies _Heliconius erato_ and _Heliconius melpomene_ provide the best studied example of mutualistic Müllerian mimicry, thought – but rarely demonstrated – to promote coevolution. Some of the strongest available evidence for coevolution comes from phylogenetic codivergence, the parallel divergence of ecologically associated lineages. Early evolutionary reconstructions suggested codivergence between mimetic populations of _H. erato_ and _H. melpomene_, and this was initially hailed as the most striking known case of coevolution. However, subsequent molecular phylogenetic analyses found discrepancies in phylogenetic branching patterns and timing (topological and temporal incongruence) that argued against codivergence. We present the first explicit cophylogenetic test of codivergence between mimetic populations of _H. erato_ and _H. melpomene_, and re-examine the timing of these radiations. We find statistically significant topological congruence between multilocus coalescent population phylogenies of _H. erato_ and _H. melpomene_, supporting repeated codivergence of mimetic populations. Divergence time estimates, based on a Bayesian coalescent model, suggest that the evolutionary radiations of _H. erato_ and _H. melpomene_ occurred over the same time period, and are compatible with a series of temporally congruent codivergence events. This evidence supports a history of reciprocal coevolution between Müllerian co-mimics characterised by phylogenetic codivergence and parallel phenotypic change
Suppression of AP1 Transcription Factor Function in Keratinocyte Suppresses Differentiation
Our previous study shows that inhibiting activator protein one (AP1) transcription factor function in murine epidermis, using dominant-negative c-jun (TAM67), increases cell proliferation and delays differentiation. To understand the mechanism of action, we compare TAM67 impact in mouse epidermis and in cultured normal human keratinocytes. We show that TAM67 localizes in the nucleus where it forms TAM67 homodimers that competitively interact with AP1 transcription factor DNA binding sites to reduce endogenous jun and fos factor binding. Involucrin is a marker of keratinocyte differentiation that is expressed in the suprabasal epidermis and this expression requires AP1 factor interaction at the AP1-5 site in the promoter. TAM67 interacts competitively at this site to reduce involucrin expression. TAM67 also reduces endogenous c-jun, junB and junD mRNA and protein level. Studies with c-jun promoter suggest that this is due to reduced transcription of the c-jun gene. We propose that TAM67 suppresses keratinocyte differentiation by interfering with endogenous AP1 factor binding to regulator elements in differentiation-associated target genes, and by reducing endogenous c-jun factor expression
High genetic diversity at the extreme range edge: nucleotide variation at nuclear loci in Scots pine (Pinus sylvestris L.) in Scotland
Nucleotide polymorphism at 12 nuclear loci was studied in Scots pine populations across an environmental gradient in Scotland, to evaluate the impacts of demographic history and selection on genetic diversity. At eight loci, diversity patterns were compared between Scottish and continental European populations. At these loci, a similar level of diversity (θsil=~0.01) was found in Scottish vs mainland European populations, contrary to expectations for recent colonization, however, less rapid decay of linkage disequilibrium was observed in the former (ρ=0.0086±0.0009, ρ=0.0245±0.0022, respectively). Scottish populations also showed a deficit of rare nucleotide variants (multi-locus Tajima's D=0.316 vs D=−0.379) and differed significantly from mainland populations in allelic frequency and/or haplotype structure at several loci. Within Scotland, western populations showed slightly reduced nucleotide diversity (πtot=0.0068) compared with those from the south and east (0.0079 and 0.0083, respectively) and about three times higher recombination to diversity ratio (ρ/θ=0.71 vs 0.15 and 0.18, respectively). By comparison with results from coalescent simulations, the observed allelic frequency spectrum in the western populations was compatible with a relatively recent bottleneck (0.00175 × 4Ne generations) that reduced the population to about 2% of the present size. However, heterogeneity in the allelic frequency distribution among geographical regions in Scotland suggests that subsequent admixture of populations with different demographic histories may also have played a role
Muscular cystic hydatidosis: case report
BACKGROUND: Hydatidosis is a zoonosis caused by Echinococcus granulosus, and ingesting eggs released through the faeces from infected dogs infects humans. The location of the hydatid cysts is mostly hepatic and/or pulmonary, whereas musculoskeletal hydatidosis is very rare. CASE PRESENTATION: We report an unusual case of primary muscular hydatidosis in proximity of the big adductor in a young Sicilian man. The patient, 34 years old, was admitted to the Department of Infectious and Tropical Diseases for ultrasonographic detection, with successive confirmation by magnetic resonance imaging, of an ovular mass (13 × 8 cm) in the big adductor of the left thigh, cyst-like, and containing several small cystic formations. Serological tests for hydatidosis gave negative results. A second drawing of blood was done 10 days after the first one and showed an increase in the antibody titer for hydatidosis. The patient was submitted to surgical excision of the lesion with perioperatory prophylaxis with albendazole. The histopathological examination of the bioptic material was not diriment in the diagnosis, therefore further tests were performed: additional serological tests for hydatidosis for the evaluation of IgE and IgG serotype (Western Blot and REAST), and molecular analysis of the excised material. These more specific serological tests gave positive results for hydatidosis, and the sequencing of the polymerase chain reaction products from the cyst evidenced E. granulosus DNA, genotype G1. Any post-surgery complications was observed during 6 following months. CONCLUSION: Cystic hydatidosis should always be considered in the differential diagnosis of any cystic mass, regardless of its location, also in epidemiological contests less suggestive of the disease. The diagnosis should be achieved by taking into consideration the clinical aspects, the epidemiology of the disease, the imaging and immunological tests but, as demonstrated in this case, without neglecting the numerous possibilities offered by new serological devices and modern day molecular biology techniques
Rightward hemispheric asymmetries in auditory language cortex in children with autistic disorder: an MRI investigation
Purpose: determine if language disorder in children with autistic disorder (AD) corresponds to abnormalities in hemispheric asymmetries in auditory language cortex. Methods: MRI morphometric study in children with AD (n = 50) to assess hemispheric asymmetries in auditory language cortex. A key region of interest was the planum temporale (PT), which is larger in the left hemisphere in most healthy individuals. Results: (i) Heschl’s gyrus and planum polare showed typical hemisphere asymmetry patterns; (ii) posterior Superior Temporal Gyrus (pSTG) showed significant rightward asymmetry; and (iii) PT showed a trend for rightward asymmetry that was significant when constrained to right-handed boys (n = 30). For right-handed boys, symmetry indices for pSTG were significantly positively correlated with those for PT. PT asymmetry was age dependent, with greater rightward asymmetry with age. Conclusions: results provide evidence for rightward asymmetry in auditory association areas (pSTG and PT) known to subserve language processing. Cumulatively, our data provide evidence for a differing maturational path for PT for lower functioning children with AD, with both pre- and post-natal experience likely playing a role in PT asymmetry
Membrane-Anchored HIV-1 N-Heptad Repeat Peptides Are Highly Potent Cell Fusion Inhibitors via an Altered Mode of Action
Peptide inhibitors derived from HIV-gp41 envelope protein play a pivotal role in deciphering the molecular mechanism of HIV-cell fusion. According to accepted models, N-heptad repeat (NHR) peptides can bind two targets in an intermediate fusion conformation, thereby inhibiting progression of the fusion process. In both cases the orientation towards the endogenous intermediate conformation should be important. To test this, we anchored NHR to the cell membrane by conjugating fatty acids with increasing lengths to the N- or C-terminus of N36, as well as to two known N36 mutants; one that cannot bind C-heptad repeat (CHR) but can bind NHR (N36 MUTe,g), and the second cannot bind to either NHR or CHR (N36 MUTa,d). Importantly, the IC50 increased up to 100-fold in a lipopeptide-dependent manner. However, no preferred directionality was observed for the wild type derived lipopeptides, suggesting a planar orientation of the peptides as well as the endogenous NHR region on the cell membrane. Furthermore, based on: (i) specialized analysis of the inhibition curves, (ii) the finding that N36 conjugates reside more on the target cells that occupy the receptors, and (iii) the finding that N36 MUTe,g acts as a monomer both in its soluble form and when anchored to the cell membrane, we suggest that anchoring N36 to the cell changes the inhibitory mode from a trimer which can target both the endogenous NHR and CHR regions, to mainly monomeric lipopetides that target primarily the internal NHR. Besides shedding light on the mode of action of HIV-cell fusion, the similarity between functional regions in the envelopes of other viruses suggests a new approach for developing potent HIV-1 inhibitors
Effects of a penthiopyrad and picoxystrobin fungicide mixtureon phoma stem canker (Leptosphaeria spp.) on UK winteroilseed rape
© Koninklijke Nederlandse Planteziektenkundige Vereniging 2016. This is a pre-copyedited, author-produced PDF of an article accepted for publication in European Journal of Plant Pathology following peer review. The final publication [Sewell, T.R., Moloney, S., Ashworth, M. et al., European Journal of Plant Pathology (2016) 145: 675-685, first published online April 5, 2016] is available at Springer via doi: http://dx.doi.org/10.1007/s10658-016-0916-8In the UK, fungicides are often used to controlphoma stem canker on winter oilseed rape. Field trialswere established near Boxworth, Cambridgeshire for fourcropping seasons (2011/2012, 2012/2013, 2013/2014 and2014/15) to test the efficacy of a new fungicide mixtureRefinzar® (penthiopyrad + picoxystrobin) by comparisonto an existing fungicide Proline 275® (prothioconazole)against phoma stem canker (Leptosphaeria spp.) andthe effect on winter oilseed rape (cv. Catana) yield. Ineach season, weather data were collected from a weatherstation at Boxworth and the release of ascospores wasmonitored using a nearby Burkard spore sampler. Thepatterns of ascospore release differed between seasonsand related to weather conditions. Fungicidespenthiopyrad + picoxystrobin and prothioconazole wereapplied in October/November when 10 % of plants hadphoma leaf spotting (T1, early), 4/8 weeks after T1 (T2,late) or at both T1 and T2 (combined). When phoma leafspot symptoms were assessed in autumn/winter,penthiopyrad + picoxystrobin and prothioconazole bothdecreased numbers of phoma leaf spots caused byL. maculans; there were few leaf spots caused byL. biglobosa. Penthiopyrad + picoxystrobin andprothioconazole both reduced phoma stem canker severitybefore harvest compared to the untreated control butdid not increase yield in these seasons when epidemicswere not severe. In 2013/2014, the presence ofL. maculans and L. biglobosa in upper stem lesions orstem base cankers was determined by species-specificPCR. The proportions of stems with L. maculans DNAwere much greater than those with L. biglobosa DNA forboth upper stem lesions and basal stem cankers. Theseresults suggest that both penthiopyrad + picoxystrobinand prothioconazole can decrease phoma stem cankerseverity on winter oilseed rape in severe disease seasons.Peer reviewe
A phase III clinical trial of exercise modalities on treatment side-effects in men receiving therapy for prostate cancer
Background: Androgen deprivation therapy (ADT) is accompanied by a number of adverse side effects including reduced bone mass and increased risk for fracture, reduced lean mass and muscle strength, mood disturbance and increased fat mass compromising physical functioning, independence, and quality of life. The purpose of this investigation is to examine the effects of long term exercise on reversing musculoskeletal-related side effects, and cardiovascular and diabetes risk factors in men receiving androgen deprivation for their prostate cancer. Specifically, we aim to investigate the effects of a 12-month exercise program designed to load the musculoskeletal system and reduce cardiovascular and diabetes disease progression on the following primary endpoints: 1) bone mineral density; 2) cardiorespiratory function and maximal oxygen capacity; 3) body composition (lean mass and fat mass); 4) blood pressure and cardiovascular function; 5) lipids and glycemic control; and 6) quality of life and psychological distress
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