Accumulation of C-terminal fragments of transactive response DNA-binding protein 43 leads to synaptic loss and cognitive deficits in human TDP-43 transgenic mice

Accumulation of the transactive response DNA-binding protein 43 (TDP-43) is a major hallmark of several neurodegenerative disorders, collectively known as TDP-43 proteinopathies. The most common TDP-43 proteinopathies, frontotemporal lobar degeneration with TDP–43-positive inclusions, and amyotrophic lateral sclerosis, share overlapping neuropathological and clinical phenotypes. The development and detailed analysis of animal models of TDP-43 proteinopathies are critical for understanding the pathogenesis of these disorders. Transgenic mice overexpressing mutant human TDP-43 (herein referred to as hTDP-43) are characterized by neurodegeneration and reduced life span. However, little is known about the behavioral phenotype of these mice. Here we report the novel finding that hTDP-43 mice develop deficits in cognition, motor performance, and coordination. We show that these behavioral deficits are associated with the accumulation of nuclear and cytosolic TDP-43 C-terminal fragments, a decrease in endogenous TDP-43 levels, and synaptic loss. Our findings provide critical insights into disease pathology, and will help guide future preclinical studies aimed at testing the effects of potential therapeutic agents on the onset and progression of TDP-43 proteinopathies.     

Marcadores pronósticos en pacientes con gammapatía monoclonal de significado incierto

Objective

The assessment of prognostic biomarkers in monoclonal gammopathies of uncertain significance (MGUS) requires using large cohorts and long follow-ups, due to the low rate of conversion to multiple myeloma (MM). The aim of this article is to develop a model that allows smaller cohorts and shorter follow-ups to be used with high reliability.

Patients and methods

A total of 64 MGUS patients were studied and followed-up prospectively for 6 ± 0.24 years. Patients were classified as evolving or non-evolving, depending on whether the monoclonal protein levels increased or not over time. The risk of conversion to MM was tested based on these phenotypes, and whether the factors that predict conversion to MM are also associated with the appearance of an evolving phenotype.

Results

Eleven patients showed an evolving phenotype, and 53 a non-evolving one. All patients who converted to MM previously showed evolving phenotype (P = .003). At diagnosis, evolving phenotype associated with monoclonal gammopathies of IgA isotype (27 vs. 9%), monoclonal IgG levels above 1,500 mg/dl (P = .007, OR 9.8) and altered kappa/lambda ratios (P = .001, OR 11.7).

Conclusions

Risk factors for developing an evolving phenotype in MGUS patients are the same as those already described for the development of MM. These data show the validity of the evolving/non-evolving model to study markers to predict the outcome of MGUS patients, and confirm the role of the levels of monoclonal IgG and the light chains ratio in the prognosis of this disease.     

Inhibitory effects of quercetin on guinea-pig ileum contractions

The inhibitory effect of quercetin on the guinea-pig ileum contractile responses was examined to further clarify its mechanism of action. Quercetin inhibited, from doses of 5 μM , the spontaneous phasic contractions of the guinea-pig ileum, as well as the phasic and tonic components of either acetylcholine- or KCl-elicited contractions, in a dose-dependent way. The former effect was reversible and was unaffected by nicotinic blockade. The tonic component of the contractions was more responsive to quercetin than the phasic component. The inhibition of the tonic contraction was, at least partially, due to the blockade of calcium channels by quercetin, since increasing calcium concentration in the tissue bath reversed the inhibition when the organ was contracted by KCl. Quercetin may also interfere with calcium release from intracellular stores, since it inhibited acetylcholine-elicited phasic contraction even in a calcium-free solution. Finally, quercetin shifted the concentration-response curves to carbachol downwards, without modifying the ED₅₀ of the agonist, whereas the concentration-response curves to CaCl₂ were shifted downwards and to the right. In conclusion, quercetin inhibits the contractile responses of guinea-pig ileum, decreasing the calcium concentration available for contractile machinery.     

Role of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in Peyronie's disease:a new diagnostic approach to predict the stage of the disease?

Neutrophil-to-lymphocyte ratio(NLR)and platelet-to-lymphocyte ratio(PLR)have been associated with multiple entities and several types of cancers.They can be ass...     

From the Cover: Complex history of the amphibian-killing chytrid fungus revealed with genome resequencing data

Understanding the evolutionary history of microbial pathogens is critical for mitigating the impacts of emerging infectious diseases on economically and ecologically important host species. We used a genome resequencing approach to resolve the evolutionary history of an important microbial pathogen, the chytrid Batrachochytrium dendrobatidis (Bd), which has been implicated in amphibian declines worldwide. We sequenced the genomes of 29 isolates of Bd from around the world, with an emphasis on North, Central, and South America because of the devastating effect that Bd has had on amphibian populations in the New World. We found a substantial amount of evolutionary complexity in Bd with deep phylogenetic diversity that predates observed global amphibian declines. By investigating the entire genome, we found that even the most recently evolved Bd clade (termed the global panzootic lineage) contained more genetic variation than previously reported. We also found dramatic differences among isolates and among genomic regions in chromosomal copy number and patterns of heterozygosity, suggesting complex and heterogeneous genome dynamics. Finally, we report evidence for selection acting on the Bd genome, supporting the hypothesis that protease genes are important in evolutionary transitions in this group. Bd is considered an emerging pathogen because of its recent effects on amphibians, but our data indicate that it has a complex evolutionary history that predates recent disease outbreaks. Therefore, it is important to consider the contemporary effects of Bd in a broader evolutionary context and identify specific mechanisms that may have led to shifts in virulence in this system.Emerging infectious diseases (EIDs) pose significant challenges for human health, agricultural crops, and economically and ecologically important populations in nature (1–4). The incidence of EIDs has been steadily rising over the last several decades (5, 6), and EIDs are of particular concern in an increasingly globalized world. For example, the majority of human EIDs is zoonoses that originate in wildlife (5) and subsequently, create a significant burden for global economies and public health (7, 8). Therefore, scientific efforts to understand and respond to EIDs are critical in diverse fields from biomedicine to conservation biology.Although EIDs result from a complex interplay of factors, many studies focus primarily on the emergence of novel microbial pathogens. There are, in fact, high-profile examples of EIDs caused by the rapid appearance of novel, hypervirulent, or host-switching strains (9–11), but EIDs are not always caused by rapid or recent evolution of the pathogen itself. Virulence itself is an emergent property of microbe–host–environment interactions (12). Thus, EIDs can result from shifts in any factor—or combination of factors—in the microbe–host–environment epidemiological triangle (13). Characterizing the evolutionary history of emerging pathogens is, thus, critical, allowing us to determine whether observed EIDs result from rapid, recent shifts in organisms with pathogenic potential.Chytridiomycosis is an EID responsible for declines in amphibian species around the world. The chytrid fungus Batrachochytrium dendrobatidis (Bd) was discovered and linked to amphibian declines in 1998 (14, 15). Chytridiomycosis is caused by Bd and kills amphibians by disrupting the integrity of their skin, a physiologically important organ that is involved in gas exchange, electrolyte balance, hydration, and protection from other pathogens (16, 17). Bd infects hundreds of species of amphibians, is found on all continents where amphibians occur, and is responsible for declines and extirpations in a diversity of amphibian hosts (18).Soon after Bd was discovered, researchers proposed two competing hypotheses for the emergence of chytridiomycosis. The emerging pathogen hypothesis posited that a novel disease agent caused chytridiomycosis, and the endemic pathogen hypothesis proposed that an environmental shift disrupted a previously benign microbe–host interaction (19). Over the years, spatiotemporal and genetic data have supported the emerging pathogen hypothesis (reviewed in refs. 20 and 21). Spatiotemporal data provided clear evidence that Bd arrived and spread through geographic regions where it was not present historically (22–24). Early genetic studies also found very little genetic differentiation in Bd with no geographic signal, consistent with a recent, rapid spread of a novel disease agent (25–27). Recently, genetic and genomic data have been used to describe a geographically widespread Bd lineage [termed the global panzootic lineage (GPL)] (28) and several putatively endemic Bd lineages (28–30). However, different studies have used different methods and focused sampling in different parts of the world, precluding integration across studies to determine the evolutionary history leading to the emergence of Bd as a global threat to amphibians.Here, we present whole-genome sequencing from a global panel of Bd isolates to show that Bd has a historically deeper and more complex evolutionary history than previously appreciated. We sequenced Bd genomes from around the world and also, a non-Bd chytrid outgroup that does not attack amphibians [Homolaphlyctis polyrhiza (Hp)] (31). Our focus was primarily on the evolutionary dynamics of Bd in the Americas, because many of the most devastating outbreaks have occurred in the New World. We address outstanding questions about the origins, genetic diversity, and genome structure of Bd that can be resolved using whole-genome data. We also integrate our genomic data with those data from a previous study with complementary geographic sampling (28). Our results reveal that the evolutionary history of Bd is complex, with multiple divergent lineages, heterogeneous patterns of genomic evolution, and no simple link between a single evolutionary event and observed amphibian declines.     

Number and size of stones in patients with asymptomatic and symptomatic gallstones and gallbladder carcinoma: A prospective study of 592 cases

The development of gallbladder carcinoma has been correlated with the presence of a single large gallstone in two retrospective studies. The objective of the present study was to determine the number and size of gallstones in patients with gallbladder carcinoma compared to asymptomatic and symptomatic female patients with gallstones. The following three groups of patients were included in this prospective trial: (A) 78 asymptomatic patients with gallstones; (B) 365 symptomatic patients with gallstones; and (C) 149 patients with gallbladder carcinoma. At the end of the operation, the resected gallbladder was opened and the number of stones counted. The maximum size of the stones was determined using calipers. Patients with gallbladder carcinoma were significantly older than patients in the other two groups (P <0.001). In the group with asymptomatic gallstones, there were significantly more patients with one single stone, whereas in the group with gallbladder carcinoma there were significantly more patients with multiple stones (more than 11; P <0.01). Patients with gallbladder carcinoma had significantly larger stones, regardless of the number of stones present (P <0.001). We postulate that the increase in the number and size of the stones among patients with gallbladder carcinoma could simply be an effect of aging or it could be a reflection of the long-term presence of stones in the gallbladder rather than some particular chemical or physical influence.     

The use of 7-amino actinomycin D in identifying apoptosis: simplicity of use and broad spectrum of application compared with other techniques

The detection and quantitation of apoptotic cells is becoming increasingly important in the investigation of the role of apoptosis in cellular proliferation and differentiation. The pathogenesis of hematologic disorders such as aplastic anemia and the development of neoplasia are believed to involve dysregulation of apoptosis. To quantitate accurately the proportion of apoptosis cells within different cell types of a heterogeneous cell population such as blood or bone marrow, a method is required that combines the analysis of large numbers of cells with concurrent immunophenotyping of cell surface antigens. In this study, we have evaluated such a method using the fluorescent DNA binding agent, 7-amino actinomycin D (7AAD), to stain three diverse human cell lines, induced to undergo apoptosis by three different stimuli. Flow cytometric analysis defines three populations on the basis of 7AAD fluorescence and forward light scatter. We have shown by cell sorting and subsequent morphological assessment and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling that the populations defined by 7AAD represent live, apoptotic, and late-apoptotic/dead cells. This method is quick, simple, reproducible, and cheap and will be a valuable tool in the investigation of the role of apoptosis in normal physiology and in disease states.