599 research outputs found
Aquagenic urticaria: A perplexing physical phenomenon
Aquagenic urticaria (AQ) is a rare physical urticaria induced by contact with water. It may be distinctive clinically, evident as 1-2 mm folliculopapular urticaria, a pattern also characteristic of cholinergic urticaria. AQ has a truncal and upper extremity distribution within 20-30 minutes after contact with water, regardless of its temperature or source. AQ is usually symptomatic with mild to severe pruritus and a burning sensation. The mechanism by which water produces mast cell degranulation and histamine release remains unclear. We review its clinical presentation, diagnostic parameters, differential diagnosis, and treatment. </span
Context integration in visual processing: a computational model of center-surround suppression in the visual system
[Poster presentation]. A dysfunction of GABAergic neurotransmission is hypothesized to be an important factor in the pathophysiology of schizophrenia [1], depression and anxiety disorders. Findings of decreased center-surround suppression (CSS, i.e. the mutual inhibition of a focal visual stimulus and its surrounding) have been interpreted in terms of GABAergic dysfunction [2]. Consistently, strongly decreased CSS is reported in schizophrenic patients [3]. However, the underlying mechanisms of this decrease remain unclearPeer reviewe
Senile Systemic Amyloidosis: Clinical Features at Presentation and Outcome
Background Cardiac amyloidosis is a fatal disease whose prognosis and treatment rely on identification of the amyloid type. In our aging population transthyretin amyloidosis (ATTRwt) is common and must be differentiated from other amyloid types. We report the clinical presentation, natural history, and prognostic features of ATTRwt compared with cardiac‐isolated AL amyloidosis and calculate the probability of disease diagnosis of ATTRwt from baseline factors.
Methods and Results All patients with biopsy‐proven ATTRwt (102 cases) and isolated cardiac AL (36 cases) seen from 2002 to 2011 at the UK National Amyloidosis Center were included. Median survival from the onset of symptoms was 6.07 years in the ATTRwt group and 1.7 years in the AL group. Positive troponin, a pacemaker, and increasing New York Heart Association (NYHA) class were associated with worse survival in ATTRwt patients on univariate analysis. All patients with isolated cardiac AL and 24.1% of patients with ATTRwt had evidence of a plasma cell dyscrasia. Older age and lower N‐terminal pro‐B‐type natriuretic peptide (NT pro‐BNP) were factors significantly associated with ATTRwt. Patients aged 70 years and younger with an NT pro‐BNP <183 pmol/L were more likely to have ATTRwt, as were patients older than 70 years with an NT pro‐BNP <1420 pmol/L.
Conclusions Factors at baseline associated with a worse outcome in ATTRwt are positive troponin T, a pacemaker, and NYHA class IV symptoms. The age of the patient at diagnosis and NT pro‐BNP level can aid in distinguishing ATTRwt from AL amyloidosis
Sex-Chromosome Homomorphy in Palearctic Tree Frogs Results from Both Turnovers and X-Y Recombination
Contrasting with birds and mammals, poikilothermic vertebrates often have homomorphic sex chromosomes, possibly resulting from high rates of sex-chromosome turnovers and/or occasional X-Y recombination. Strong support for the latter mechanism was provided by four species of European tree frogs, which inherited from a common ancestor (∼5 Ma) the same pair of homomorphic sex chromosomes (linkage group 1, LG1), harboring the candidate sex-determining gene Dmrt1. Here, we test sex linkage of LG1 across six additional species of the Eurasian Hyla radiation with divergence times ranging from 6 to 40 Ma. LG1 turns out to be sex linked in six of nine resolved cases. Mapping the patterns of sex linkage to the Hyla phylogeny reveals several transitions in sex-determination systems within the last 10 My, including one switch in heterogamety. Phylogenetic trees of DNA sequences along LG1 are consistent with occasional X-Y recombination in all species where LG1 is sex linked. These patterns argue against one of the main potential causes for turnovers, namely the accumulation of deleterious mutations on nonrecombining chromosomes. Sibship analyses show that LG1 recombination is strongly reduced in males from most species investigated, including some in which it is autosomal. Intrinsically low male recombination might facilitate the evolution of male heterogamety, and the presence of important genes from the sex-determination cascade might predispose LG1 to become a sex chromosom
Antiphospholipid Antibodies Bind ATP: A putative Mechanism for the Pathogenesis of Neuronal Dysfunction
Antiphospholipid antibodies (aPL) generated in experimental animals
cross-react with ATP. We therefore examined the possibility that aPL IgG from
human subjects bind to ATP by affinity column and an enzyme linked
immunosorbent assay (ELISA). Sera with high levels of aPL IgG were collected
from 12 patients with the antiphospholipid syndrome (APS). IgG fractions from
10 of 12 APS patients contained aPL that could be affinity-bound to an ATP
column and completely eluted with NaCl 0.5 M. A significant (>50%) inhibition
of aPL IgG binding by ATP 5 mM was found in the majority. Similar inhibition
was obtained with ADP but not with AMP or cAMP. All the affinity purified
anti-ATP antibodies also bound β2-glycoprotein-I (β2-GPI, also known as
apolipoprotein H) suggesting that, similar to most pathogenic aPL, their binding
depends on this serum cofactor. We further investigated this possibility and found
that the binding of β2-GPI to the ATP column was similar to that of aPL IgG in
that most was reversed by NaCl 0.5 M. Furthermore, addition of β2-GPI to aPL
IgG significantly increased the amount of aPL binding to an ATP column. We
conclude that aPL IgG bind ATP, probably through β2-GPI. This binding could
interfere
with the normal extracellular function of ATP and similar neurotransmitters
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