Active chiral fluids Fürthauer, S.; Strempel, M.; Grill, S. W. ...
The European physical journal. E, Soft matter and biological physics,
09/2012, Letnik:
35, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia ...and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.
We study the dynamics of active polar fluids in a Taylor-Couette geometry where the fluid is confined between two rotating coaxial cylinders. This system can spontaneously generate flow fields and ...thereby set the two cylinders into relative rotation either by spontaneous symmetry breaking or via asymmetric boundary conditions on the polarization field at the cylinder surfaces. In the presence of an externally applied torque, the system can act as a rotatory motor and perform mechanical work. The relation between the relative angular velocity of the cylinders and the externally applied torque exhibits rich behaviors such as dynamic instabilities and the coexistence of multiple stable steady states for certain ranges of parameter values and boundary conditions.
Physical activity (PA) helps prevention and aftercare of sporadic breast cancer (BC), cardiopulmonary fitness (CPF) being an age-independent predictor of tumor-specific mortality. Therefore, we ...wanted to identify predictors of CPF (represented by peak oxygen uptake: VO
) in BRCA1/2 mutation carriers whose risk of developing BC is high. We used cross-sectional data from 68 BRCA1/2 germline mutation carrying women participating in the randomized, prospective, controlled clinical study LIBRE-1. Assessments included cardiopulmonary exercise testing, medical and lifestyle history plus socioeconomic status. Additionally, the participants completed a psychological questionnaire regarding their attitude, subjective norms, perceived behavior control and intention towards PA. A multivariate logistic regression model was used to identify predictors for participants reaching their age- and sex-adjusted VO
reference values. 22 participants (median age: 40 years, interquartile range (IQR) 33-46) were cancer-unaffected and 46 cancer-affected (median age: 44 years, IQR 35-50). The strongest predictor for reaching the reference VO
value was attitude towards PA (Odds Ratio 3.0; 95% Confidence Interval 1.3-8.4; p = 0.021). None of the other predictors showed a significant association. A positive attitude towards PA seems to be associated with VO
, which should be considered in developing therapeutic and preventive strategies.Trial registrations: NCT02087592; DRKS00005736.
Active chiral processes in thin films Fürthauer, S; Strempel, M; Grill, S W ...
Physical review letters,
2013-Jan-25, Letnik:
110, Številka:
4
Journal Article
Recenzirano
We develop a generic description of thin active films that captures key features of flow and rotation patterns emerging from the activity of chiral motors which introduce torque dipoles. We highlight ...the role of the spin rotation field and show that fluid flows can occur in two ways: by coupling of the spin rotation rate to the velocity field via a surface or by spatial gradients of the spin rotation rate. We discuss our results in the context of patches of bacteria on solid surfaces and groups of rotating cilia. Our theory could apply to active chiral processes in the cell cytoskeleton and in epithelia.
The Methods of Optimal Depression Detection in Parkinson's Disease (MOOD-PD) study compared the psychometric properties of 9 depression scales to provide guidance on scale selection in Parkinson ...disease (PD).
Patients with PD (n = 229) from community-based neurology practices completed 6 self-report scales (Beck Depression Inventory BDI-II, Center for Epidemiologic Studies Depression Rating Scale-Revised CESD-R, 30-item Geriatric Depression Scale GDS-30, Inventory of Depressive Symptoms-Patient IDS-SR, Patient Health Questionnaire-9 PHQ-9, and Unified Parkinson's Disease Rating Scale UPDRS-Part I) and were administered 3 clinician-rated scales (17-item Hamilton Depression Rating Scale HAM-D-17, Inventory of Depressive Symptoms-Clinician IDS-C, and Montgomery-Åsberg Depression Rating Scale MADRS and a psychiatric interview. DSM-IV-TR diagnoses were established by an expert panel blinded to the self-reported rating scale data. Receiver operating characteristic curves were used to estimate the area under the curve (AUC) of each scale.
All scales performed better than chance (AUC 0.75-0.85). Sensitivity ranged from 0.66 to 0.85 and specificity ranged from 0.60 to 0.88. The UPDRS Depression item had a smaller AUC than the BDI-II, HAM-D-17, IDS-C, and MADRS. The CESD-R also had a smaller AUC than the MADRS. The remaining AUCs were statistically similar.
The GDS-30 may be the most efficient depression screening scale to use in PD because of its brevity, favorable psychometric properties, and lack of copyright protection. However, all scales studied, except for the UPDRS Depression, are valid screening tools when PD-specific cutoff scores are used.
Background
Patients with cervical dystonia (CD) typically require regular injections of botulinum toxin to maintain symptomatic control. We aimed to document long-term patient satisfaction with CD ...symptom control in a large cohort of patients treated in routine practice.
Methods
This was a prospective, international, observational study (NCT01753349) following the course of adult CD treated with botulinum neurotoxin type A (BoNT-A) over 3 years. A comprehensive clinical assessment status was performed at each injection visit and subjects reported satisfaction in two ways: satisfaction with symptom control at peak effect and at the end of treatment cycle.
Results
Subject satisfaction remained relatively stable from the first to the last injection visit. At 3 years, 89.9% of subjects reported satisfaction with symptom control at peak effect and 55.6% reported satisfaction with symptom control at end of treatment cycle. By contrast, objective ratings of CD severity showed an overall reduction over 3 years. Mean ± SD Toronto Western Spasmodic Rating Scale (TWSTRS) Total scores (clinician assessed at end of treatment cycle) decreased from 31.59 ± 13.04 at baseline to 24.49 ± 12.43 at 3 years (mean ± SD reduction from baseline of − 6.97 ± 11.56 points). Tsui scale scores also showed gradual improvement; the percent of subjects with a tremor component score of 4 reduced from 12.4% at baseline to 8.1% at 3 years.
Conclusions
Despite objective clinical improvements over 3 years, subject satisfaction with symptom control remained relatively constant, indicating that factors other than symptom control also play a role in patient satisfaction.
Previous studies from our laboratories have shown that (a) Triapine
™ is a potent inhibitor of ribonucleotide reductase activity and (b) hydroxyurea-resistant L1210 leukemia cells are fully sensitive ...to Triapine. In an analogous manner, Triapine was similarly active against the wild-type and a hydroxyurea-resistant subline of the human KB nasopharyngeal carcinoma. Triapine was active
in vivo against the L1210 leukemia over a broad range of dosages and was curative for some mice. This agent also caused pronounced inhibition of the growth of the murine M109 lung carcinoma and human A2780 ovarian carcinoma xenografts in mice. Optimum anticancer activity required twice daily dosing due to the duration of inhibition of DNA synthesis which lasted about 10 hr in L1210 cells treated with Triapine
in vivo. DNA synthesis in normal mouse tissues (i.e. duodenum and bone marrow) uniformly recovered faster than that in L1210 leukemia cells, demonstrating a pharmacological basis for the therapeutic index of this agent. Triapine was more potent than hydroxyurea in inhibiting DNA synthesis in L1210 cells
in vivo, and the effects of Triapine were more pronounced. In addition, the duration of the inhibition of DNA synthesis in leukemia cells from mice treated with Triapine was considerably longer than in those from animals treated with hydroxyurea. Combination of Triapine with various classes of agents that damage DNA (e.g. etoposide, cisplatin, doxorubicin, and 1-acetyl-1,2-bis(methylsulfonyl)-2-(2-chloroethyl)hydrazine) resulted in synergistic inhibition of the L1210 leukemia, producing long-term survivors of tumor-bearing mice treated with several dosage levels of the combinations, whereas no enhancement of survival was found when Triapine was combined with gemcitabine or cytosine arabinoside. The findings demonstrate the superiority of Triapine over hydroxyurea as an anticancer agent and further suggest that prevention by Triapine of repair of DNA lesions created by agents that damage DNA may result in efficacious drug combinations for the treatment of cancer.
To determine the prevalence and impact of comorbid psychiatric disturbances in Parkinson disease (PD) patients with psychosis.
Subject data were derived from a research database of 116 PD patients ...participating in standardized motor, cognitive, psychiatric, and caregiver assessments.
There were 25 patients (22%) with psychosis manifest as hallucinations (n = 9), delusions (n = 1), or hallucinations and delusions (n = 15) and 25 patients (22%) who had no current or past psychiatric comorbidities (PDN). In the psychotic group, 44% had psychosis only (PSY), and 56% had psychosis plus at least one other comorbid psychiatric disturbance (PSY+), including depressive disorders (71%), anxiety disorders (21%), apathetic syndromes (14%), and delirium (14%). There were no differences in age, sex, education, or age onset or duration of PD among the PSY, PSY+, and PDN groups. Both psychotic groups had greater motor, functional, and frontal cognitive deficits and increased caregiver burden scores relative to PDN. PSY+ showed greater global and selective cognitive deficits compared to PDN. Psychosis was a primary predictor of caregiver burden, whereas depressive symptoms indirectly enhanced motor impairments.
Nonpsychotic psychiatric disturbances, especially affective disturbances, are common comorbidities in PD patients with psychosis and warrant clinical attention to reduce morbidity and caregiver distress.
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