Reduced Activation of the Gla19Ala FX Variant via the Extrinsic Coagulation Pathway Results in Symptomatic CRMred FX Deficiency

We characterized a symptomatic CRMred factor X (FX) deficiency produced by the Glu19Ala mutation in the γ-carboxyglutamic-rich domain. FX activity levels in plasma were markedly reduced in prothrombin time assays (< 1-5%), whereas in activated partial thromboplastin assays (16%) and in RVV assays (17%) the reduction in activity mirrored that in antigen levels (17%). Activation of recombinant 19Ala-FX by factor IXa/factor VIIIa or RVV, and the activity in thrombin generation assays, were comparable to those of wild-type FX. Differently, complete activation of recombinant 19AlaFX required a factor VIIa/TF concentration 30-fold higher than that of wild-type FX. The recombinant FVIIa significantly reduced PT values in 19Ala-FX reconstituted plasma, thus suggesting an alternative approach for treatment of FX deficiencies characterized by defective FX activation.

The study of this FX deficiency provides an “in vivo” and “in vitro” model for the investigation of Gla domain interactions.

Role of cardiovascular magnetic resonance in suspected cardiac amyloidosis: late gadolinium enhancement pattern as mortality predictor

BACKGROUND

Cardiac magnetic resonance (CMR) has gained a central role in the diagnosis of cardiac amyloidosis (CA). While the diagnostic role of a typical late gadolinium enhancement (LGE) pattern (global subendocardial enhancement coupled with accelerated contrast washout) has been identified, evidence is still conflicting regarding the prognostic role of such examination.

METHODS AND RESULTS

We retrospectively analysed all patients referring for CMR at Niguarda Hospital (Milan, Italy) from January 2006 to January 2015 for suspected CA. Primary outcome was all-cause mortality. We identified 42 patients and divided them into 2 groups, according to the presence (Group A) or absence (Group B) of a typical amyloidosis LGE pattern. At the end of the follow-up (median 37 months, interquartile range 10-50 months), 31 patients (74%) had died. The hazard ratio for all-cause death was 3.2 (95% confidence interval [CI] 1.5-6.4, p < 0.01) for Group A versus Group B. Median survival time was 17 months (95% CI 7-42 months) for Group A and 70 months (95% CI 49-94 months) for Group B (p < 0.01). Multivariate analysis did not find any adjunctive predictive role for biventricular volumes and ejection fraction, indexed left ventricular mass, transmitral E/e' at echocardiography, age at diagnosis or serum creatinine.

CONCLUSION

In our population, a typical LGE pattern was significantly associated with higher mortality. Moreover, patients with a typical LGE pattern showed a globally worse prognosis. Our data suggest that the LGE pattern may play a central role in prognostic stratification of patients with suspected CA, thus prompting further diagnostic and therapeutic measures.

Chiari-like malformation in two cats

Two male, neutered, domestic, shorthaired cats were evaluated for progressive paresis and ataxia. Neurological examinations suggested a spinal cord lesion in each case. Complete blood examination and cerebrospinal fluid analysis were unremarkable in both cats. MRI revealed malformation of the occipital bone with herniation of the cerebellar vermis through the foramen magnum but without syringomyelia. Chiari-like malformation was suspected in both patients. MRI repeated one year later in both cats because of progression of clinical signs yielded the same findings as the initial scans. Foramen magnum decompression in one cat was associated with resolution of clinical signs.

A New AI Evaluation Cosmos: Ready to Play the Game?

We report on a series of new platforms and events dealing with AI evaluation that may change the way in which AI systems are compared and their progress is measured. The introduction of a more diverse and challenging set of tasks in these platforms can feed AI research in the years to come, shaping the notion of success and the directions of the field. However, the playground of tasks and challenges presented there may misdirect the field without some meaningful structure and systematic guidelines for its organization and use. Anticipating this issue, we also report on several initiatives and workshops that are putting the focus on analyzing the similarity and dependencies between tasks, their difficulty, what capabilities they really measure and – ultimately – on elaborating new concepts and tools that can arrange tasks and benchmarks into a meaningful taxonomy.

The pre-launch characterization of SIMBIO-SYS/VIHI imaging spectrometer for the BepiColombo mission to Mercury. II. Spectral calibrations

The Visible and near Infrared Hyperspectral Imager (VIHI) is the VIS-IR spectrometer with imaging capabilities aboard the ESA BepiColombo mission to Mercury. In this second paper, we report the instrument spectral characterization derived by the calibration campaign carried out before spacecraft integration. Complementary measurements concerning radiometric and linearity responses, as well as geometric performances, are described in Paper I [G. Filacchione et al., Rev. Sci. Instrum. 88, 094502 (2017)]. We have verified the VIHI spectral range, spectral dispersion, spectral response function, and spectral uniformity along the whole slit. Instrumental defects and optical aberrations due to smiling and keystone effects have been evaluated, and they are lower than the design requirement (<1/3 pixel). The instrumental response is uniform along the whole slit, while spectral dispersion is well represented by a second order curve, rather than to be constant along the spectral dimension.

The pre-launch characterization of SIMBIO-SYS/VIHI imaging spectrometer for the BepiColombo mission to Mercury. I. Linearity, radiometry, and geometry calibrations

Before integration aboard European Space Agency BepiColombo mission to Mercury, the visible and near infrared hyperspectral imager underwent an intensive calibration campaign. We report in Paper I about the radiometric and linearity responses of the instrument including the optical setups used to perform them. Paper II [F. Altieri et al., Rev. Sci. Instrum. 88, 094503 (2017)] will describe complementary spectral response calibration. The responsivity is used to calculate the expected instrumental signal-to-noise ratio for typical observation scenarios of the BepiColombo mission around Mercury. A description is provided of the internal calibration unit that will be used to verify the relative response during the instrument's lifetime. The instrumental spatial response functions as measured along and across the spectrometer's slit direction were determined by means of spatial scans performed with illuminated test slits placed at the focus of a collimator. The dedicated optical setup used for these measurements is described together with the methods used to derive the instrumental spatial responses at different positions within the 3.5^° field of view and at different wavelengths in the 0.4-2.0 μm spectral range. Finally, instrument imaging capabilities and Modulated Transfer Function are tested by using a standard mask as a target.

Multimodal Word Meaning Induction From Minimal Exposure to Natural Text

By the time they reach early adulthood, English speakers are familiar with the meaning of thousands of words. In the last decades, computational simulations known as distributional semantic models (DSMs) have demonstrated that it is possible to induce word meaning representations solely from word co-occurrence statistics extracted from a large amount of text. However, while these models learn in batch mode from large corpora, human word learning proceeds incrementally after minimal exposure to new words. In this study, we run a set of experiments investigating whether minimal distributional evidence from very short passages suffices to trigger successful word learning in subjects, testing their linguistic and visual intuitions about the concepts associated with new words. After confirming that subjects are indeed very efficient distributional learners even from small amounts of evidence, we test a DSM on the same multimodal task, finding that it behaves in a remarkable human-like way. We conclude that DSMs provide a convincing computational account of word learning even at the early stages in which a word is first encountered, and the way they build meaning representations can offer new insights into human language acquisition.

Anticholinergic Burden and Functional Status in Older People with Cognitive Impairment: Results from the Regal Project

OBJECTIVE

The use of drugs with intrinsic anticholinergic properties is widespread among old age persons. A growing body of evidences suggest that a high anticholinergic burden is associated with physical and cognitive impairment. However, the association between anticholinergic drug use and functional status is still poorly investigated, particularly among subjects with initial cognitive impairment.

DESIGN

Cross-sectional study examining the association between drug-related anticholinergic burden and functional status in cognitively healthy (CH) (n=691), mild cognitive impairment (MCI) (n=541) or mild Alzheimer's diseases (AD) (n=1127) subjects.

SETTING

Data were gathered from the ReGAl project (Rete Geriatrica Alzheimer-Geriatric Network on Alzheimer's disease), a large longitudinal Italian multicentric clinical-based study, promoted by the Italian Society of Gerontology and Geriatrics (SIGG).

PARTICIPANTS

2359 outpatients, older than 65 years, admitted to memory clinics. The total sample size, estimated according to a global effect size of 25% with type I error of 0.05 and a power of 95% is 2010 subjects.

MEASUREMENT

Functional status was evaluated by the Katz Index of Independence in Activities of Daily Living (ADL) and the Lawton-Brody Instrumental Activities of Daily Living (IADL) scales. The drug-related anticholinergic burden was estimated by the Anticholinergic Risk Scale (ARS).

RESULTS

The 15.9 % (n=375) of total population used at least one drug with anticholinergic properties. Such a drug use was associated with partially dependence in ADL (OR:1.42, CI95%: 1.10-1.83; p=0.006), independently of gender, number of drugs, comorbidity index, presence of clinically relevant neuropsychiatric symptoms and adjusted MMSE. Anticholinergic drug use was associated with un-ability at each IADL task only in male MCI subjects, with significant impairment in shopping (p=0.011), and drug management (p=0.05).

CONCLUSIONS

The use of medications with anticholinergic properties is common among older persons cognitively health as well as with cognitive impairment. Our results suggest that the use of anticholinergic drugs is associated with functional impairment, especially in old age subjects with initial cognitive impairment. Minimizing anticholinergic burden should result in maintaining daily functioning, especially in a vulnerable population, such as MCI and mild AD.

Neural sensitivity to syllable frequency and mutual information in speech perception and production

Many factors affect our ability to decode the speech signal, including its quality, the complexity of the elements that compose it, as well as their frequency of occurrence and co-occurrence in a language. Syllable frequency effects have been described in the behavioral literature, including facilitatory effects during speech production and inhibitory effects during word recognition, but the neural mechanisms underlying these effects remain largely unknown. The objective of this study was to examine, using functional neuroimaging, the neurobiological correlates of three different distributional statistics in simple 2-syllable nonwords: the frequency of the first and second syllables, and the mutual information between the syllables. We examined these statistics during nonword perception and production using a powerful single-trial analytical approach. We found that repetition accuracy was higher for nonwords in which the frequency of the first syllable was high. In addition, brain responses to distributional statistics were widespread and almost exclusively cortical. Importantly, brain activity was modulated in a distinct manner for each statistic, with the strongest facilitatory effects associated with the frequency of the first syllable and mutual information. These findings show that distributional statistics modulate nonword perception and production. We discuss the common and unique impact of each distributional statistic on brain activity, as well as task differences.

Peripheral Nerve Pathology in Two Rottweilers with Neuronal Vacuolation and Spinocerebellar Degeneration

Neuronal vacuolation and spinocerebellar degeneration in young Rottweiler dogs is a neurodegenerative condition characterized by neuronal vacuolation of several nuclei in the central nervous system and degeneration of the spinal cord white matter. Here, we describe the morphologic and ultrastructural findings in laryngeal muscles and peripheral nerves of a 16-week-old female and a 32-week-old female Rottweiler dog affected by progressive ataxia and tetraparesis associated with laryngeal paralysis. Lesions were characterized by neurogenic muscle atrophy of the intrinsic laryngeal muscles, and a loss of large myelinated fibers in the recurrent laryngeal nerve, accompanied by demyelinating/remyelinating features affecting the small myelinated fibers. No significant changes were detected in the cranial laryngeal, vagus, phrenic, ulnar, or peroneal nerves. These findings were indicative of a selective distal neuropathy of the recurrent laryngeal nerve with early severe axonal degeneration, mainly of the large myelinated fibers.

A novel inhibitor of p75-neurotrophin receptor improves functional outcomes in two models of traumatic brain injury

The p75 neurotrophin receptor is important in multiple physiological actions including neuronal survival and neurite outgrowth during development, and after central nervous system injury. We have discovered a novel piperazine-derived compound, EVT901, which interferes with p75 neurotrophin receptor oligomerization through direct interaction with the first cysteine-rich domain of the extracellular region. Using ligand binding assays with cysteine-rich domains-fused p75 neurotrophin receptor, we confirmed that EVT901 interferes with oligomerization of full-length p75 neurotrophin receptor in a dose-dependent manner. Here we report that EVT901 reduces binding of pro-nerve growth factor to p75 neurotrophin receptor, blocks pro-nerve growth factor induced apoptosis in cells expressing p75 neurotrophin receptor, and enhances neurite outgrowth in vitro. Furthermore, we demonstrate that EVT901 abrogates p75 neurotrophin receptor signalling by other ligands, such as prion peptide and amyloid-β. To test the efficacy of EVT901 in vivo, we evaluated the outcome in two models of traumatic brain injury. We generated controlled cortical impacts in adult rats. Using unbiased stereological analysis, we found that EVT901 delivered intravenously daily for 1 week after injury, reduced lesion size, protected cortical neurons and oligodendrocytes, and had a positive effect on neurological function. After lateral fluid percussion injury in adult rats, oral treatment with EVT901 reduced neuronal death in the hippocampus and thalamus, reduced long-term cognitive deficits, and reduced the occurrence of post-traumatic seizure activity. Together, these studies provide a new reagent for altering p75 neurotrophin receptor actions after injury and suggest that EVT901 may be useful in treatment of central nervous system trauma and other neurological disorders where p75 neurotrophin receptor signalling is affected.

Activated factor VII-antithrombin complex predicts mortality in patients with stable coronary artery disease: a cohort study

BACKGROUND

Plasma concentration of activated factor VII (FVIIa)-antithrombin (AT) complex has been proposed as an indicator of intravascular exposure of tissue factor.

OBJECTIVES

The aims of this observational study were to evaluate (i) FVIIa-AT plasma concentration in subjects with or without coronary artery disease (CAD) and (ii) its association with mortality in a prospective cohort of patients with CAD.

METHODS

FVIIa-AT levels were measured by elisa in 686 subjects with (n = 546) or without (n = 140) angiographically proven CAD. Subjects with acute coronary syndromes and those taking anticoagulant drugs at the time of enrollment were excluded. CAD patients were followed for total and cardiovascular mortality.

RESULTS

There was no difference in FVIIa-AT levels between CAD (84.8 with 95% confidence interval [CI] 80.6-88.2 pmol L(-1) ) and CAD-free subjects (83.9 with 95% CI 76.7-92.8 pmol L(-1) ). Within the CAD population, during a 64-month median follow-up, patients with FVIIa-AT levels higher than the median value at baseline (≥ 79 pmol L(-1) ) had a two-fold greater risk of both total and cardiovascular mortality. Results were confirmed after adjustment for sex, age, the other predictors of mortality (hazard ratio for total mortality: 2.05 with 95% CI 1.22-3.45, hazard ratio for cardiovascular mortality 1.94 with 95% CI 1.01-3.73, with a slight improvement of C-statistic over traditional risk factors), FVIIa levels, drug therapy at discharge, and even patients using all the usual medications for CAD treatment. High FVIIa-AT levels also correlated with increased thrombin generation.

CONCLUSIONS

This preliminary study suggests that plasma concentration of FVIIa-AT is a thrombophilic marker of total and cardiovascular mortality risk in patients with clinically stable CAD.

The carboxyl-terminal region is NOT essential for secreted and functional levels of coagulation factor X

BACKGROUND

The homologous coagulation factor X (FX), VII (FVII), IX (FIX) and protein C (PC) display striking differences in the carboxyl-terminus, with that of FX being the most extended. This region is essential for FVII, FIX and PC secretion.

OBJECTIVES

To provide experimental evidence for the role of the FX carboxyl-terminus.

METHODS

Recombinant FX (rFX) variants were expressed in multiple eukaryotic cell systems. Protein and activity levels were evaluated by ELISA, coagulant and amidolytic assays.

RESULTS AND DISCUSSION

Expression of a panel of progressively truncated rFX variants in HEK293 cells revealed that the deletion of up to 21 residues in the carboxyl-terminus did not significantly affect secreted protein levels, as confirmed in HepG2 and BHK21 cells. In contrast, chimeric rFX-FVII variants with swapped terminal residues showed severely reduced levels. The truncated rFX variants revealed normal amidolytic activity, suggesting an intact active site. Intriguingly, these variants, which included that resembling the activated FXβ form once cleaved, also displayed remarkable or normal pro-coagulant capacity in PT- and aPTT-based assays. This supports the hypothesis that subjects with nonsense mutations in the FX carboxyl-terminus, so far never identified, would be asymptomatic.

CONCLUSIONS

For the first time we demonstrate that the FX carboxyl-terminal region downstream of residue K467 is not essential for secretion and provides a modest contribution to pro-coagulant properties. These findings, which might suggest an involvement of the carboxyl-terminal region in the divergence of the homologous FX, FVII, FIX and PC, help to interpret the mutational pattern of FX deficiency.

Reading visually embodied meaning from the brain: Visually grounded computational models decode visual-object mental imagery induced by written text

Embodiment theory predicts that mental imagery of object words recruits neural circuits involved in object perception. The degree of visual imagery present in routine thought and how it is encoded in the brain is largely unknown. We test whether fMRI activity patterns elicited by participants reading objects' names include embodied visual-object representations, and whether we can decode the representations using novel computational image-based semantic models. We first apply the image models in conjunction with text-based semantic models to test predictions of visual-specificity of semantic representations in different brain regions. Representational similarity analysis confirms that fMRI structure within ventral-temporal and lateral-occipital regions correlates most strongly with the image models and conversely text models correlate better with posterior-parietal/lateral-temporal/inferior-frontal regions. We use an unsupervised decoding algorithm that exploits commonalities in representational similarity structure found within both image model and brain data sets to classify embodied visual representations with high accuracy (8/10) and then extend it to exploit model combinations to robustly decode different brain regions in parallel. By capturing latent visual-semantic structure our models provide a route into analyzing neural representations derived from past perceptual experience rather than stimulus-driven brain activity. Our results also verify the benefit of combining multimodal data to model human-like semantic representations.

Asymmetric processing of mutant factor X Arg386Cys reveals differences between intrinsic and extrinsic pathway activation

Alterations in coagulation factor X (FX) activation, mediated by the extrinsic VIIa/tissue factor (FVIIa/TF) or the intrinsic factor IXa/factor VIIIa (FIXa/FVIIIa) complexes, can result in hemorrhagic/prothrombotic tendencies. However, the molecular determinants involved in substrate recognition by these enzymes are poorly defined. Here, we investigated the role of arginine 386 (chymotrypsin numbering c202), a surface-exposed residue on the FX catalytic domain. The naturally occurring FX386Cys mutant and FX386Ala variant were characterized. Despite the unpaired cysteine, recombinant (r)FX386Cys was efficiently secreted (88.6±21.3% of rFXwt) and possessed normal clearance in mice. rFX386Cys was also normally activated by FVIIa/TF and displayed intact amidolytic activity. In contrast, rFX386Cys activation by the FIXa/FVIIIa complex was 4.5-fold reduced, which was driven by a decrease in the kcat (1.6∗10(-4) s(-1) vs 5.8∗10(-4) s(-1), rFXwt). The virtually unaltered Km (70.6 nM vs 55.6nM, rFXwt) suggested no major alterations in the FX substrate exosite. Functional assays in plasma supplemented with rFX386Cys indicated a remarkable reduction in the thrombin generation rate and thus in coagulation efficiency. Consistently, the rFX386Ala variant displayed similar biochemical features suggesting that global changes at position 386 impact the intrinsic pathway activation. These data indicate that the FXArg386 is involved in FIXa/FVIIIa-mediated FX activation and help in elucidating the bleeding tendency associated with the FX386Cys in a rare FX deficiency case. Taking advantage of the unpaired cysteine, the rFX386Cys mutant may be efficiently targeted by thiol-specific ligands and represent a valuable tool to study FX structure-function relationships both in vitro and in vivo.

Combination therapy with indacaterol and glycopyrronium bromide in the management of COPD: an update on the evidence for efficacy and safety

The international guidelines on chronic obstructive pulmonary disease (COPD) recommend inhaled bronchodilators for maintenance treatment of the disease. These drugs include β2-agonists and muscarinic antagonists, which are both available as short-acting agents (to be used as needed for dyspnea) and long-acting agents. To the latter belong salmeterol and formoterol (long-acting β2-agonists) and indacaterol, vilanterol and olodaterol (very long-acting β2-agonist) as β2-agonists, and tiotropium, aclidinium and glycopyrronium bromide as long-acting muscarinic antagonists. The efficacy and safety of indacaterol and glycopyrronium as monotherapies has been demonstrated in several controlled trials. However, in some patients with moderate-to-severe COPD, symptoms are poorly controlled by bronchodilator monotherapy; in these cases the addition of a second bronchodilator from a different pharmacological class may be beneficial. Here we review the evidence from published randomized trials concerning the efficacy and safety of the once-daily fixed-dose dual bronchodilator combining indacaterol and glycopyrronium.

Interaction between bone and muscle in older persons with mobility limitations

Aging is associated with a progressive loss of bone-muscle mass and strength. When the decline in mass and strength reaches critical thresholds associated with adverse health outcomes, they are operationally considered geriatric conditions and named, respectively, osteoporosis and sarcopenia. Osteoporosis and sarcopenia share many of the same risk factors and both directly or indirectly cause higher risk of mobility limitations, falls, fractures and disability in activities of daily living. This is not surprising since bones adapt their morphology and strength to the long-term loads exerted by muscle during anti-gravitational and physical activities. Non-mechanical systemic and local factors also modulate the mechanostat effect of muscle on bone by affecting the bidirectional osteocyte-muscle crosstalk, but the specific pathways that regulate these homeostatic mechanisms are not fully understood. More research is required to reach a consensus on cut points in bone and muscle parameters that identify individuals at high risk for adverse health outcomes, including falls, fractures and disability. A better understanding of the muscle-bone physiological interaction may help to develop preventive strategies that reduce the burden of musculoskeletal diseases, the consequent disability in older persons and to limit the financial burden associated with such conditions. In this review, we summarize age-related bone-muscle changes focusing on the biomechanical and homeostatic mechanisms that explain bone-muscle interaction and we speculate about possible pathological events that occur when these mechanisms become impaired. We also report some recent definitions of osteoporosis and sarcopenia that have emerged in the literature and their implications in clinical practice. Finally, we outline the current evidence for the efficacy of available anti-osteoporotic and proposed antisarcopenic interventions in older persons.