The role of stellar expansion on the formation of gravitational wave sources

Massive stars are the progenitors of black holes and neutron stars, the mergers of which can be detected with gravitational waves (GW). The expansion of massive stars is one of the key factors affecting their evolution in close binary systems, but it remains subject to large uncertainties in stellar astrophysics. For population studies and predictions of GW sources, the stellar expansion is often simulated with the analytic formulae from Hurley et al. (2000). These formulae need to be extrapolated for stars beyond 50 solar masses and are often considered outdated. In this work we present five different prescriptions developed from 1D stellar models to constrain the maximum expansion of massive stars. We adopt these prescriptions to investigate how stellar expansion affects mass transfer interactions and in turn the formation of GW sources. We show that limiting radial expansion with updated 1D stellar models, when compared to the use of Hurley et al. (2000) radial expansion formulae, does not significantly affect GW source properties (rates and masses). This is because most mass transfer events leading to GW sources are initialised before the donor star reaches its maximum expansion. The only significant difference was found for the mass distribution of massive binary black hole mergers (total mass > 50 solar masses) formed from stars that may evolve beyond the Humphreys-Davidson limit, whose radial expansion is the most uncertain. We conclude that understanding the expansion of massive stars and the origin of the Humphrey-Davidson limit is a key factor for the study of GW sources.Comment: Accepted for publication in MNRA

A new index to assess turning quality and postural stability in patients with Parkinson's disease

Parkinson's disease is a neuro-degenerative disorder characterized by the progressive death of dopamine neurons. This leads to delayed and uncoordinated movements, and impacts on the patients’ motor performance with reduced movement intensity, increased axial rigidity and impaired cadence regulation. Turning provides privileged insights in postural instability and fall prediction, as it is regularly performed during daily activities, requires multi-limb coordination. The objective of this work was to define a Quality of Movement (QoM) index, inferred from inertial data related to turns, and strictly correlated with the patient's motor conditions, postural stability, and stage of the disease. Such a concise representation finds its main application in the remote monitoring of patients during daily activities at home. We have recorded and analyzed 180° turns in 72 patients, using inertial sensors embedded in the smartphone. We have set up an algorithm for binary classification of patients: mild vs. moderate/severe conditions, according to the Hoehn and Yahr scale of disease progression and disability degree. Our QoM index is defined as the a posteriori probability output by this binary classifier. It exhibits high correlation (r = 0.73) with the clinical score of postural stability, as well as with the average of four clinical scores related to movement impairment (r = 0.75). These results, together with the widespread smartphone use, provide a step in the direction of a practical, objective and reliable tool for PD patients remote monitoring in domestic environment

Levodopa-carbidopa intestinal gel infusion and weight loss in Parkinson's disease

© 2018 EANBackground and purpose: Weight loss (WL) is a frequent yet under-recognized complication of levodopa/carbidopa intestinal gel (LCIG) infusion, as well as a milestone of Parkinson's disease (PD) disability progression. The complex association between WL, poor nutritional status, motor complications and PD progression, however, remains unclear. Methods: Consecutive consenting patients with PD treated with LCIG (n = 44; PD duration, 18.3 ± 6.5 years) were enrolled in an open-label observational study assessing the extent of WL occurring during LCIG treatment. As secondary aims, we correlated the nutritional status, as detected by the Mini Nutritional Assessment, with the severity of motor symptoms [Movement Disorder Society Unified Parkinson's Disease Rating Scale part III], motor complications (Unified Parkinson's Disease Rating Scale part IV), activities of daily living (Schwab and England scale), cognitive impairment (Mini Mental State Examination), depression (Beck Depression Inventory), difficulties in feeding (Edinburgh Feeding Evaluation in Dementia Questionnaire) and levodopa equivalent daily dose (LEDD). Results: There was an average WL of 9.9 ± 10.5% (7.6 ± 7.1 kg) over an LCIG treatment period of 51.6 ± 28.5 months. The extent of WL correlated with the percentage of the waking day spent with dyskinesia (P < 0.05). The nutritional status correlated with motor symptom severity (P < 0.01), dysphagia (P < 0.01) and LEDD (P < 0.01). Conclusions: Weight loss may occur in patients with PD undergoing LCIG in correlation with the percentage of the waking day spent with dyskinesia. Regardless of the extent of WL, the nutritional status correlated with higher LEDD, as well as with indices of disease progression, such as motor symptom severity and dysphagia.info:eu-repo/semantics/publishedVersio

Machine learning applied to ambulatory blood pressure monitoring: a new tool to diagnose autonomic failure?

BACKGROUND: Autonomic failure (AF) complicates Parkinson’s disease (PD) in one-third of cases, resulting in complex blood pressure (BP) abnormalities. While autonomic testing represents the diagnostic gold standard for AF, accessibility to this examination remains limited to a few tertiary referral centers. OBJECTIVE: The present study sought to investigate the accuracy of a machine learning algorithm applied to 24-h ambulatory BP monitoring (ABPM) as a tool to facilitate the diagnosis of AF in patients with PD. METHODS: Consecutive PD patients naïve to vasoactive medications underwent 24 h-ABPM and autonomic testing. The diagnostic accuracy of a Linear Discriminant Analysis (LDA) model exploiting ABPM parameters was compared to autonomic testing (as per a modified version of the Composite Autonomic Symptom Score not including the sudomotor score) in the diagnosis of AF. RESULTS: The study population consisted of n = 80 PD patients (33% female) with a mean age of 64 ± 10 years old and disease duration of 6.2 ± 4 years. The prevalence of AF at the autonomic testing was 36%. The LDA model showed 91.3% accuracy (98.0% specificity, 79.3% sensitivity) in predicting AF, significantly higher than any of the ABPM variables considered individually (hypotensive episodes = 82%; reverse dipping = 79%; awakening hypotension = 74%). CONCLUSION: LDA model based on 24-h ABPM parameters can effectively predict AF, allowing greater accessibility to an accurate and easy to administer test for AF. Potential applications range from systematic AF screening to monitoring and treating blood pressure dysregulation caused by PD and other neurodegenerative disorders

The Role of HE4 in Ovarian Cancer Follow-up: A Review.

Objective: The aim of this review was to analyze the state of the art about HE4 and follow-up in patients treated for ovarian cancer. Methods: A literature search was conducted in the MEDLINE database using the key words "HE4" and "ovarian cancer" and "recurrence" or "relapse" or "follow up." Results: Seven of 28 clinical studies were selected. Four studies were prospective, and all of them were based on a small number of patients (8Y73 women). A failure of HE4 levels to normalize at completion of standard therapy may indicate a poor prognosis, thus suggesting the need of a closer follow-up. Moreover, HE4 showed better sensibility and specificity in the diagnosis of ovarian cancer recurrence with respect to CA-125, being also an earlier indicator of the relapse with a lead time of 5 to 8 months. HE4 showed a better performance in this setting if performed in association with other markers (CA-125, CA-72.4). HE4 seems to be an independent predictive factor for the surgical outcome at secondary cytoreductive surgery and to maintain its prognostic role even after the recurrence. Conclusions: These preliminary data start to suggest a superiority of HE4 over CA-125 in the detection of ovarian cancer recurrence. Moreover, the prognostic role of HE4 could help clinicians to personalize the follow-up program, whereas its predictive role could be useful to plan the treatment of the relapse. The role of HE4 in ovarian cancer follow-up deserves to be further investigated in prospective randomized multicentric studies

Chromosomal and environmental contributions to sex differences in the vulnerability to neurological and neuropsychiatric disorders: Implications for therapeutic interventions

Neurological and neuropsychiatric disorders affect men and women differently. Multiple sclerosis, Alzheimer's disease, anxiety disorders, depression, meningiomas and late-onset schizophrenia affect women more frequently than men. By contrast, Parkinson's disease, autism spectrum condition, attention-deficit hyperactivity disorder, Tourette's syndrome, amyotrophic lateral sclerosis and early-onset schizophrenia are more prevalent in men. Women have been historically under-recruited or excluded from clinical trials, and most basic research uses male rodent cells or animals as disease models, rarely studying both sexes and factoring sex as a potential source of variation, resulting in a poor understanding of the underlying biological reasons for sex and gender differences in the development of such diseases. Putative pathophysiological contributors include hormones and epigenetics regulators but additional biological and non-biological influences may be at play. We review here the evidence for the underpinning role of the sex chromosome complement, X chromosome inactivation, and environmental and epigenetic regulators in sex differences in the vulnerability to brain disease. We conclude that there is a pressing need for a better understanding of the genetic, epigenetic and environmental mechanisms sustaining sex differences in such diseases, which is critical for developing a precision medicine approach based on sex-tailored prevention and treatment

How resistant are levodopa-resistant axial symptoms? Response of freezing, posture, and voice to increasing levodopa intestinal infusion rates in Parkinson disease

Background and purpose: Treatment of freezing of gait (FoG) and other Parkinson disease (PD) axial symptoms is challenging. Systematic assessments of axial symptoms at progressively increasing levodopa doses are lacking. We sought to analyze the resistance to high levodopa doses of FoG, posture, speech, and altered gait features presenting in daily-ON therapeutic condition. Methods: We performed a pre-/postinterventional study including patients treated with levodopa/carbidopa intestinal gel infusion (LCIG) with disabling FoG in daily-ON condition. Patients were evaluated at their usual LCIG infusion rate (T1), and 1 h after 1.5× (T2) and 2× (T3) increase of the LCIG infusion rate by quantitative outcome measures. The number of FoG episodes (primary outcome), posture, speech, and gait features were objectively quantified during a standardized test by a blinded rater. Changes in motor symptoms, dyskinesia, and plasma levodopa concentrations were also analyzed. Results: We evaluated 16 patients with a mean age of 69 ± 9.4 years and treated with LCIG for a mean of 2.2&nbsp;± 2.1 years. FoG improved in 83.3% of patients by increasing the levodopa doses. The number of FoG episodes significantly decreased (mean&nbsp;=&nbsp;2.3 at T1, 1.7 at T2, 1.2 at T3; p&nbsp;= 0.013). Posture and speech features did not show significant changes, whereas stride length (p&nbsp;= 0.049), turn duration (p&nbsp;= 0.001), and turn velocity (p&nbsp;= 0.024) significantly improved on doubling the levodopa infusion rate. Conclusions: In a short-term evaluation, the increase of LCIG dose can improve "dopa-resistant" FoG and gait issues in most advanced PD patients with overall good control of motor symptoms in the absence of clinically significant dyskinesia