225 research outputs found
Members of opposite sex mutually regulate gonadal recrudescence in the lizard Calotes versicolor (Agamidae)
Adult males and females of the seasonally breeding lizard Calotes versicolor were subjected to various social situations under semi-natural conditions to explain the role of socio-sexual factors in gonadal recrudescence. They were grouped as: (i) males and females, (ii) males and females separated by a wire mesh, (iii) same sex groups of males or females, (iv) castrated males with intact females and (v) ovariectomized (OvX) females with intact males from postbreeding to breeding phase. Specimens collected from the wild during breeding season served as the control group. Plasma sex steroid levels (testosterone in male and 17β-estradiol in female), spermatogenetic activity and vitellogenesis were the criteria to judge gonadal recrudescence. In intact males and females that were kept together, gonadal recrudescence and plasma sex steroids levels were comparable to those in wild-caught individuals. Gonadal recrudescence was at its least in all male and all female groups, and plasma sex steroids were at basal levels. Association with OvX females initiated testicular recrudescence but spermatogenetic activity progressed only up to the spermatid stage while males separated from females by wire mesh showed spermatogenetic activity for a shorter period. Females grouped with castrated males and those separated from males by wire mesh produced vitellogenic follicles. However, the total number and diameter of vitellogenic follicles, and plasma estradiol levels were lower than in the females grouped with intact males. The findings indicate that association with members of the opposite sex with progressively rising titers of sex steroids is crucial in both initiating and sustaining gonadal recrudescence in the lizard. Thus, members of the opposite sex mutually regulate gonadal recrudescence in the C. versicolor
Intensive glycemic treatment during Type 1 diabetes pregnancy: A story of (mostly) sweet success!
Studies from Scotland and Canada confirm large increases in the incidence of pregnancies complicated by pregestational type 1 diabetes (T1D). With this increased antenatal workload comes more specialization and staff expertise, which may be important as diabetes technology use increases. While euglycemia remains elusive and obstetrical intervention (earlier delivery, increased operative deliveries) is increasing, there have been some notable successes in the past 5–10 years. These include a decline in the rates of congenital anomaly (Canada) and stillbirths (U.K.) and substantial reductions in both maternal hypoglycemia (both moderate and severe) across many countries. However, pregnant women with T1D still spend ∼30–45% of the time (8–11 h/day) hyperglycemic during the second and third trimesters. The duration of maternal hyperglycemia appears unchanged in routine clinical care over the past decade. This ongoing fetal exposure to maternal hyperglycemia likely explains the persistent rates of large for gestational age (LGA), neonatal hypoglycemia, and neonatal intensive care unit (NICU) admissions in T1D offspring. The Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) found that pregnant women using real-time continuous glucose monitoring (CGM) spent 5% less time (1.2 h/day) hyperglycemic during the third trimester, with clinically relevant reductions in LGA, neonatal hypoglycemia, and NICU admissions. This article will review the progress in our understanding of the intensive glycemic treatment of T1D pregnancy, focusing in particular on the recent technological advances in CGM and automated insulin delivery. It suggests that even with advanced diabetes technology, optimal maternal dietary intake is needed to minimize the neonatal complications attributed to postprandial hyperglycemia
Implementation of a community-based exercise program for Parkinson patients: using boxing as an example
Background: Persons with Parkinson’s disease (PD) benefit from continuous exercise through participation in community-based exercise programs. However, community programs often lack PD-specific knowledge needed to provide safe and adequately dosed exercise.Objective: To evaluate the acceptability and safety of a PD-specific boxing program in the community.Methods:We developed specific educational resources to facilitate the boxing instructors.We also organized an educational and practicalworkshop for patients (n = 26) and instructors (n = 10), and assessed: (a) participants’ satisfaction; (b) instructors’ appreciation of the educational resources; and (c) numbers of patients interested in participating in the boxing program. After 18 months, patients and instructors completed a questionnaire evaluating: (a) participants’ satisfaction; (b) adverse events; (c) facilitators and barriers; and (d) proportion of participants at follow-up.Results: Twenty-six persons with PD (62% men) and 10 boxing instructors participated in the workshop. 81% of patients and 80% of instructors were very satisfied. Instructors found the educational materials “very helpful” (60%) or “helpful” (40%). Patients expressed a clear interest (54%) or possible interest (46%) in the program.We initiated classes with 10 participants. At 18-months follow-up, the program consisted of four boxing sessions/week, led by three instructors, with 40 participants. Seventeen patients responded to the questionnaire at follow-up. Participants were “very satisfied” (53%), “satisfied” (35%) and neither satisfied nor unsatisfied (12%) with the program. Adverse effects were mild (e.g., muscle aches). Transportation and physical disability were the main barriers for participation.Conclusions: The boxing program was well-received, with increasing numbers of participants at 18 months. The educational resources can support boxing instructors participating in current and future boxing classes being delivered in the community.info:eu-repo/semantics/publishedVersio
Evolution of surface gravity waves over a submarine canyon
The effects of a submarine canyon on the propagation of ocean surface waves
are examined with a three-dimensional coupled-mode model for wave propagation
over steep topography. Whereas the classical geometrical optics approximation
predicts an abrupt transition from complete transmission at small incidence
angles to no transmission at large angles, the full model predicts a more
gradual transition with partial reflection/transmission that is sensitive to
the canyon geometry and controlled by evanescent modes for small incidence
angles and relatively short waves. Model results for large incidence angles are
compared with data from directional wave buoys deployed around the rim and over
Scripps Canyon, near San Diego, California, during the Nearshore Canyon
Experiment (NCEX). Wave heights are observed to decay across the canyon by
about a factor 5 over a distance shorter than a wavelength. Yet, a spectral
refraction model predicts an even larger reduction by about a factor 10,
because low frequency components cannot cross the canyon in the geometrical
optics approximation. The coupled-mode model yields accurate results over and
behind the canyon. These results show that although most of the wave energy is
refractively trapped on the offshore rim of the canyon, a small fraction of the
wave energy 'tunnels' across the canyon. Simplifications of the model that
reduce it to the standard and modified mild slope equations also yield good
results, indicating that evanescent modes and high order bottom slope effects
are of minor importance for the energy transformation of waves propagating
across depth contours at large oblique angles
Post-Operative Carbonate-Apatite Formation in PEO/PBT Copolymers (Polyactive®)
Previous studies have stressed the importance of calcification of the polyethylene oxide (PEO) I polybutylene terephthalate (PBT) copolymer surface by establishing a direct relation with the occurrence of bone-bonding. Here, we characterized the morphology as well as the composition of this post-operative reaction product in PEOIPBT copolymers. X-ray · photoelectron spectroscopical results demonstrated the ability of PEOIPBT copolymers to rapidly adsorb calcium ions from fluids. After subcutaneous implantation in rats, it was shown that polymer calcification comprised plate-shaped crystals, whereas an electron-dense layer was frequently encountered at the interface. Cells with a characteristic morphology were directly apposed to abundantly calcified surfaces, indicating the biocompatible nature of the material. Subcutaneous calcification was composed of a carbonate-apatite structure with a crystallinity comparable to bone mineral as demonstrated by Fourier transformed infrared spectroscopy and X-ray diffraction.
It was concluded that the post-operative reaction product in PEOIPBT copolymers is, in morphology and composition, highly comparable to the carbonate-containing apatitic surface layer generated on acknowledged bioactive substrates and similar to the inorganic phase of bone apatite. This may, partially, explain the bone-bonding behaviour of PEOIPBT copolymers
Modeling water waves beyond perturbations
In this chapter, we illustrate the advantage of variational principles for
modeling water waves from an elementary practical viewpoint. The method is
based on a `relaxed' variational principle, i.e., on a Lagrangian involving as
many variables as possible, and imposing some suitable subordinate constraints.
This approach allows the construction of approximations without necessarily
relying on a small parameter. This is illustrated via simple examples, namely
the Serre equations in shallow water, a generalization of the Klein-Gordon
equation in deep water and how to unify these equations in arbitrary depth. The
chapter ends with a discussion and caution on how this approach should be used
in practice.Comment: 15 pages, 1 figure, 39 references. This document is a contributed
chapter to an upcoming volume to be published by Springer in Lecture Notes in
Physics Series. Other author's papers can be downloaded at
http://www.denys-dutykh.com
Multidisciplinary care for people with Parkinson’s disease:the new kids on the block!
INTRODUCTION: Parkinson's disease (PD) is a chronic multisystem disorder that causes a wide variety of motor and non-motor symptoms. Over time, the progressive nature of the disease increases the risk of complications such as falls and loss of independence, having a profound impact on quality of life. The complexity and heterogeneity of symptoms therefore warrant a holistic, multidisciplinary approach. Specific healthcare professionals, e.g. the movement disorders neurologist and the PD nurse specialist, are considered essential members of this multidisciplinary team. However, with our increasing knowledge about different aspects of the disease, other disciplines are also being recognized as important contributors to the healthcare team. Areas covered: The authors describe a selection of these relatively newly-recognized disciplines, including the specialist in vascular medicine, gastroenterologist, pulmonologist, neuro-ophthalmologist, urologist, geriatrician/elderly care physician, palliative care specialist and the dentist. Furthermore, they share the view of a person with PD on how patients and caregivers should be involved in the multidisciplinary team. Finally, they have included a perspective on the new role of the movement disorder neurologist, with care delivery via 'tele-neurology'. Expert commentary: Increased awareness about the potential role of these 'new' professionals will further improve disease management and quality of life of PD patients
Ectopic bone formation in cell-seeded poly(ethylene oxide)/poly(butylene terephthalate) copolymer scaffolds of varying porosity
Scaffolds from poly(ethylene oxide) and poly(butylene terephthalate), PEOT/PBT, with a PEO molecular weight of 1,000 and a PEOT content of 70 weight% (1000PEOT70PBT30) were prepared by leaching salt particles (425–500 μm). Scaffolds of 73.5, 80.6 and 85.0% porosity were treated with a CO2 gas plasma and seeded with rat bone marrow stromal cells (BMSCs). After in vitro culture for 7 days (d) in an osteogenic medium the scaffolds were subcutaneously implanted for 4 weeks in nude mice. Poly(d, l-lactide) (PDLLA) and biphasic calcium phosphate (BCP) scaffolds were included as references. After 4 weeks (wks) all scaffolds showed ectopic formation of bone and bone marrow. For the scaffolds of different porosities, no significant differences were observed in the relative amounts of bone (7–9%) and bone marrow (6–11%) formed, even though micro computed tomography (μ-CT) data showed considerable differences in accessible pore volume and surface area. 1000PEOT70PBT30 scaffolds with a porosity of 85% could not maintain their original shape in vivo. Surprisingly, 1000PEOT70PBT30 scaffolds with a porosity of 73.5% showed cartilage formation. This cartilage formation is most likely due to poorly accessible pores in the scaffolds, as was observed in histological sections. μ-CT data showed a considerably smaller accessible pore volume (as a fraction of the total volume) than in 1000PEOT70PBT30 scaffolds of 80.6 and 85.0% porosity. BMSC seeded PDLLA (83.5% porosity) and BCP scaffolds (29% porosity) always showed considerably more bone and bone marrow formation (bone marrow formation is approximately 40%) and less fibrous tissue ingrowth than the 1000PEOT70PBT30 scaffolds. The scaffold material itself can be of great influence. In more hydrophobic and rigid scaffolds like the PDLLA or BCP scaffolds, the accessibility of the pore structure is more likely to be preserved under the prevailing physiological conditions than in the case of hydrophilic 1000PEOT70PBT30 scaffolds. Scaffolds prepared from other PEOT/PBT polymer compositions, might prove to be more suited
Age and gender differences in non-motor symptoms in people with Parkinson’s disease
BackgroundNon-motor symptoms of Parkinson’s disease (PD) are highly prevalent and heterogenic. Previous studies aimed to gain more insight on this heterogeneity by investigating age and gender differences in non-motor symptom severity, but findings were inconsistent. Furthermore, besides examining the single effects of age and gender, the interaction between them in relation to non-motor functioning has -as far as we know- not been investigated before.ObjectivesTo investigate the association of age and gender identity -as well as the interaction between age and gender identity- with non-motor symptoms and their impact on quality of life.MethodsWe combined three large and independent studies. This approach resulted in a total number of unique participants of 1,509. We used linear regression models to assess the association of age and gender identity, and their interaction, with non-motor symptoms and their impact on quality of life.ResultsOlder people with PD generally had worse cognitive functioning, worse autonomic functioning and worse quality of life. Women with PD generally experienced more anxiety, worse autonomic functioning and worse quality of life compared to men with PD, whereas men with PD generally had worse cognitive functioning. In interaction analyses by age and gender identity, depressive symptoms and anxiety were disproportionally worse with increasing age in women compared to men.ConclusionOur findings indicate that both age and gender -as well as their interaction- are differentially associated with non-motor symptoms of PD. Both research and clinical practice should pay more attention to demographic subgroups differences and possible different treatment approaches with respect to age and gender. We showed how combining datasets is of added value in this kind of analyses and encourage others to use similar approaches
- …