The Finnish prostate cancer screening trial: Analyses on the screening failures

Prostate cancer (PC) screening with prostate‐specific antigen (PSA) has been shown to decrease PC mortality in the European Randomized Study of Screening for Prostate Cancer (ERSPC). However, in the Finnish trial, which is the largest component of the ERSPC, no statistically significant mortality reduction was observed. We investigated which had the largest impact on PC deaths in the screening arm: non‐participation, interval cancers or PSA threshold. The screening (SA) and control (CA) arms comprised altogether 80,144 men. Men in the SA were screened at four‐year intervals and referred to biopsy if the PSA concentration was ≥4.0 ng/ml, or 3.0–3.99 ng/ml with a free/total PSA ratio ≤16%. The median follow‐up was 15.0 years. A counterfactual exclusion method was applied to estimate the effect of three subgroups in the SA: the non‐participants, the screen‐negative men with PSA ≥3.0 ng/ml and a subsequent PC diagnosis, and the men with interval PCs. The absolute risk of PC death was 0.76% in the SA and 0.85% in the CA; the observed hazard ratio (HR) was 0.89 (95% confidence interval (CI) 0.76–1.04). After correcting for non‐attendance, the HR was 0.78 (0.64–0.96); predicted effect for a hypothetical PSA threshold of 3.0 ng/ml the HR was 0.88 (0.74–1.04) and after eliminating the effect of interval cancers the HR was 0.88 (0.74–1.04). Non‐participating men in the SA had a high risk of PC death and a large impact on PC mortality. A hypothetical lower PSA threshold and elimination of interval cancers would have had a less pronounced effect on the screening impact.     

Navigated transcranial magnetic stimulation of the primary somatosensory cortex impairs perceptual processing of tactile temporal discrimination

Previous studies indicate that transcranial magnetic stimulation (TMS) with biphasic pulses applied approximately over the primary somatosensory cortex (S1) suppresses performance in vibrotactile temporal discrimination tasks; these previous results, however, do not allow separating perceptual influence from memory or decision-making. Moreover, earlier studies using external landmarks for directing biphasic TMS pulses to the cortex do not reveal whether the changes in vibrotactile task performance were due to action on S1 or an adjacent area. In the present study, we determined whether the S1 area representing a cutaneous test site is critical for perceptual processing of tactile temporal discrimination. Electrical test pulses were applied to the thenar skin of the hand and the subjects attempted to discriminate single from twin pulses. During discrimination task, monophasic TMS pulses or sham TMS pulses were directed anatomically accurately to the S1 area representing the thenar using magnetic resonance image-guided navigation. The subject's capacity to temporal discrimination was impaired with a decrease in the delay between the TMS pulse and the cutaneous test pulse from 50 to 0 ms. The result indicates that S1 area representing a cutaneous test site is involved in perceptual processing of tactile temporal discrimination.     

Vaccines: could asthma in young children be a preventable disease? ‬‬‬‬‬‬‬

?The long battle with asthma is far from over in developed countries. Its incidence, prevalence, and severity have been increasing for decades. By reducing the risk for asthma, significant healthcare costs can be saved. The desire to create a vaccine that might prevent asthma in young children is attractive and widely considered one of the main goals in translational asthma research. Several vaccination strategies have been tested. These include allergen‐specific immunotherapy, vaccination against infectious pathogens, and modification of cell and cytokine responses. The lack of success in the prevention of asthma in young children lies on the complexity of the disease, which involves many genetic, epigenetic, and environmental interactions. This review provides a summary of current literature and aims to address key questions how to develop vaccines to prevent asthma in young children. ??????????????     

The binding of the small heat-shock protein αB-crystallin to fibrils of α-synuclein is driven by entropic forces

Molecular chaperones are key components of the cellular proteostasis network whose role includes the suppression of the formation and proliferation of pathogenic aggregates associated with neurodegenerative diseases. The molecular principles that allow chaperones to recognize misfolded and aggregated proteins remain, however, incompletely understood. To address this challenge, here we probe the thermodynamics and kinetics of the interactions between chaperones and protein aggregates under native solution conditions using a microfluidic platform. We focus on the binding between amyloid fibrils of α-synuclein, associated with Parkinson’s disease, to the small heat-shock protein αB-crystallin, a chaperone widely involved in the cellular stress response. We find that αB-crystallin binds to α-synuclein fibrils with high nanomolar affinity and that the binding is driven by entropy rather than enthalpy. Measurements of the change in heat capacity indicate significant entropic gain originates from the disassembly of the oligomeric chaperones that function as an entropic buffer system. These results shed light on the functional roles of chaperone oligomerization and show that chaperones are stored as inactive complexes which are capable of releasing active subunits to target aberrant misfolded species.

Molecular chaperones are crucial components of the cellular proteostasis network and are characteristically overexpressed during cell stress (1–4). Their roles involve the suppression of aberrant processes, including misfolding and aggregation of proteins, within the context of the complex flux of protein production and degradation. In addition to guiding nascent proteins toward their native structures following biosynthesis on ribosomes, chaperones are increasingly recognized as inhibitors of key steps in the aberrant conversion of normally soluble proteins into amyloid fibrils, protein aggregates that are associated with a wide range of neurodegenerative diseases (5–8). The overall process that leads to the formation of amyloid fibrils consists of a series of microscopic events, including primary and secondary nucleation and fibril elongation and fragmentation (9). Recent analysis of the kinetics of aggregation of several proteins has revealed that molecular chaperones can inhibit the process of amyloid formation through a variety of different microscopic mechanisms (10). In some cases, molecular chaperones have been found to suppress a single specific microscopic step in the aggregation process. In other cases, they have been shown to affect more than one type of aggregation event (7, 8, 11, 12). The modulation of the different molecular steps of protein aggregation is mediated by the binding of chaperones to misfolded protein monomers and various aggregates (11, 13, 14). For a comprehensive understanding of such inhibition processes it is therefore crucial to elucidate the thermodynamic and kinetic determinants of the binding of chaperones to different species populated during amyloid formation.A prevalent group of molecular chaperones that inhibit amyloid formation are the small heat-shock proteins (sHsps), including the vertebrate αB-crystallin (αB-c). The structure of αB-c is a conserved α-crystallin domain with a β-sheet structure, flanked by a hydrophobic N-terminal region and a polar C-terminal tail, both structurally flexible and mutually different (15). Similar to other sHsps in solution, αB-c exists in a polydisperse oligomeric state characterized by dynamic subunit exchange leading to oligomers with 10 to 50 subunits and molecular weights from 300 to 1,000 kDa (16, 17). αB-c has been shown to inhibit the overall amyloid formation process of α-synuclein (α-syn), a protein closely associated with the onset and progression of Parkinson’s disease (18). The mechanism of inhibition has been shown to originate from interactions of the chaperone with aggregated forms of α-syn, ranging from oligomers to mature amyloid fibrils, rather than with α-syn monomers (19, 20). In particular, it has been demonstrated that αB-c binds to α-syn fibrils and inhibits their elongation in solution, thus suppressing the toxicity associated with α-syn aggregation in cells (13, 21).The mechanistic importance of the interactions of αB-c with protein aggregates raises the key question of how chaperones recognize misfolded and aggregated proteins among the diverse ensemble of native states. Elucidating the binding interactions between these proteins poses fundamental challenges that originate from the heterogeneity and dynamic nature of the systems. Both the chaperone and aggregate populations are polydisperse, and the large difference in size between relatively small chaperones and high-molecular-weight client protein aggregates make interactions between them difficult to access with conventional biophysical techniques designed to probe interactions between individual biomolecules (22, 23). We have addressed these limitations using a microfluidic platform to characterize the binding (24). By exploiting the different diffusion coefficients of bound and unbound chaperones we have shown that it is possible to quantify the thermodynamics and the kinetics of binding on the time scale of minutes, where the spatial variation in concentration along the device has a negligible effect on the kinetics due to the short measurement times (24, 25). Here, we apply this approach to identify the intermolecular interactions underlying the recognition of α-syn amyloid fibrils by αB-c and to characterize the energetic trade-off during this binding process in a quantitative manner.     

Seshat: A Web service for accurate annotation,validation, and analysis of TP53 variants generated by conventional and next‐generation sequencing

Accurate annotation of genomic variants in human diseases is essential to allow personalized medicine. Assessment of somatic and germline TP53 alterations has now reached the clinic and is required in several circumstances such as the identification of the most effective cancer therapy for patients with chronic lymphocytic leukemia (CLL). Here, we present Seshat, a Web service for annotating TP53 information derived from sequencing data. A flexible framework allows the use of standard file formats such as Mutation Annotation Format (MAF) or Variant Call Format (VCF), as well as common TXT files. Seshat performs accurate variant annotations using the Human Genome Variation Society (HGVS) nomenclature and the stable TP53 genomic reference provided by the Locus Reference Genomic (LRG). In addition, using the 2017 release of the UMD_TP53 database, Seshat provides multiple statistical information for each TP53 variant including database frequency, functional activity, or pathogenicity. The information is delivered in standardized output tables that minimize errors and facilitate comparison of mutational data across studies. Seshat is a beneficial tool to interpret the ever‐growing TP53 sequencing data generated by multiple sequencing platforms and it is freely available via the TP53 Website, http://p53.fr or directly at http://vps338341.ovh.net/ .     

Photodynamic ablation of lymphatic vessels and intralymphatic cancer cells prevents metastasis

The dissemination of tumor cells to sites far from the primary tumor (metastasis) is the principal cause of death in cancer patients. Tumor-associated lymphatic vessels are a key conduit for metastatic tumor cells, which typically first colonize the lymph nodes. Although the primary tumor and affected lymph nodes can be removed during surgery, tumor cells inside lymphatic vessels are left behind. Here, we show that in-transit tumor cells inside lymphatic vessels in mice bearing mouse melanomas or human lung tumors give rise to metastases. Using photodynamic therapy with the benzoporphyrin derivative verteporfin, we selectively destroyed lymphatic vessels in mice and pigs. Destruction of tumor-associated lymphatic vessels also eradicated intralymphatic tumor cells and prevented metastasis of mouse melanoma cells and subsequent relapse. Photodynamic therapy, when combined with anti-lymphangiogenic therapy, prevented further tumor invasion of lymphatic vessels. These findings highlight the potential of targeting in-transit tumor cells in patients.     

Sushi repeat‐containing protein X‐linked 2: A novel phylogenetically conserved hypothalamo‐pituitary protein

Sushi repeat‐containing protein X‐linked 2 (SRPX2) is a novel protein associated with language development, synaptic plasticity, tissue remodeling, and angiogenesis. We investigated the expression and spatial localization of SRPX2 in normal mouse, rat, monkey, and human brain using in situ hybridization and immunohistochemistry. Antibody specificity was determined using in vitro siRNA based silencing of SRPX2. Cell type‐specific expression was verified by double‐labeling with oxytocin or vasopressin. Western blot was used to detect SRPX2 protein in rat and human plasma and cerebrospinal fluid. Unexpectedly, SRPX2 mRNA expression levels were strikingly higher in the hypothalamus as compared to the cortex. All SRPX2 immunoreactive (ir) neurons were localized in the hypothalamic paraventricular, periventricular, and supraoptic nuclei in mouse, rat, monkey, and human brain. SRPX2 colocalized with vasopressin or oxytocin in paraventricular and supraoptic neurons. Hypothalamic SRPX2‐ir positive neurons gave origin to dense projections traveling ventrally and caudally toward the hypophysis. Intense axonal varicosities and terminal arborizations were identified in the rat and human neurohypophysis. SRPX2‐ir cells were also found in the adenohypophysis. Light SRPX2‐ir projections were observed in the dorsal and ventral raphe, locus coeruleus, and the nucleus of the solitary tract in mouse, rat and monkey. SRPX2 protein was also detected in plasma and CSF. Our data revealed intense phylogenetically conserved expression of SRPX2 protein in distinct hypothalamic nuclei and the hypophysis, suggesting its active role in the hypothalamo‐pituitary axis. The presence of SRPX2 protein in the plasma and CSF suggests that some of its functions depend on secretion into body fluids.     

Predicting one-year mortality of critically ill patients with early acute kidney injury: data from the prospective multicenter FINNAKI study

IntroductionNo predictive models for long-term mortality in critically ill patients with acute kidney injury (AKI) exist. We aimed to develop and validate two predictive models for one-year mortality in patients with AKI based on data (1) on intensive care unit (ICU) admission and (2) on the third day (D3) in the ICU.MethodsThis substudy of the FINNAKI study comprised 774 patients with early AKI (diagnosed within 24 hours of ICU admission). We selected predictors a priori based on previous studies, clinical judgment, and differences between one-year survivors and non-survivors in patients with AKI. We validated the models internally with bootstrapping.ResultsOf 774 patients, 308 (39.8%, 95% confidence interval (CI) 36.3 to 43.3) died during one year. Predictors of one-year mortality on admission were: advanced age, diminished premorbid functional performance, co-morbidities, emergency admission, and resuscitation or hypotension preceding ICU admission. The area under the receiver operating characteristic curve (AUC) (95% CI) for the admission model was 0.76 (0.72 to 0.79) and the mean bootstrap-adjusted AUC 0.75 (0.74 to 0.75). Advanced age, need for mechanical ventilation on D3, number of co-morbidities, higher modified SAPS II score, the highest bilirubin value by D3, and the lowest base excess value on D3 remained predictors of one-year mortality on D3. The AUC (95% CI) for the D3 model was 0.80 (0.75 to 0.85) and by bootstrapping 0.79 (0.77 to 0.80).ConclusionsThe prognostic performance of the admission data-based model was acceptable, but not good. The D3 model for one-year mortality performed fairly well in patients with early AKI.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0848-2) contains supplementary material, which is available to authorized users.     

Exercise simultaneously increases nasal patency and bronchial obstruction in asthmatic children

We found that simultaneous post‐exercise increase in nasal patency and bronchial obstruction occurs only in children with atopic asthma, but not in sensitized children without asthma. In healthy children, the increase in nasal patency is accompanied by bronchial dilatation.