210 research outputs found

    Indinavir/Low-dose Ritonavir Containing HAART in HIV-1 Infected Children has Potent Antiretroviral Activity, but is Associated with Side Effects and Frequent Discontinuation of Treatment

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    We here present the study results of 21 HIV-1 infected children who were treated with indinavir plus low-dose ritonavir and two nucleoside reverse transcriptase inhibitors (NRTIs) for 48 weeks. Although this q12h HAART regimen had potent antiretroviral activity, it was frequently associated with side effects and discontinuation of therapy

    'VOR' - an interactive iPad model of the combined angular and linear vestibulo-ocular reflex

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    The mammalian vestibular system consists of a series of sensory organs located in the labyrinths of the inner ear that are sensitive to angular and linear movements of the head. Afferent inputs from the vestibular end organs contribute to balance, proprioception and vision. The vestibulo-ocular reflex (VOR) driven by these sensory inputs produces oculomotor responses in a direction opposite to head movement which tend to stabilise visual images on the retina. We present a model, in the form of a software application called VOR, which represents a simplified view of this complex system. The basis for our model is the hypothesis that afferent vestibular signals are integrated to maintain a notional internal representation of the head position (RHP). The vestibulo-ocular reflex maintains gaze towards a world-fixed point relative to the RHP, regardless of the actual head position. The RHP will imperfectly match the real head position when end organ input imperfectly reports head movements, such as can occur in cases of organ dysfunction and even in healthy subjects due to adaptation to motion stimuli. We do not claim that any specific observable part of the real vestibulo-ocular system corresponds to the RHP, but it seems reasonable to suggest that it might exist as a literal "neural network", trained through evolution and experience to maintain gaze during head movement. We hypothesise that the real VOR is supported by this internal representation, continually updated by afferent signals from the vestibular end organs, and that VOR eye responses tend to direct the eyes towards a fixed point in the world. Human vestibulo-ocular research typically employs equipment to which a subject is securely attached and allows rotation around, and sometimes linear movement along, one or more axes ("rotating chair") while attempting to maintain gaze on a fixation point, fixed relative to the head or world. A series of consecutive movements are referred to as a "motion profile". Meanwhile eye movements are recorded, using scleral search coils (or, more recently, video cameras and image-processing software) which can detect the horizontal, vertical and torsional components of the direction of each eye. VOR allows the user to define motion profiles and predicts the eye movements that a researcher or clinician might expect to observe in a real subject during such motion profiles. For example, the "on-centre rotation" motion profile specifies that the subject's head is positioned upright and centred around the vertical axis of the rotating chair, with a chair-fixed fixation point 1m in front of the subject. The chair accelerates angularly to 200°/sec over 20 seconds, rotates at a constant 200°/sec for 60 seconds, then decelerates to stationary over 20 seconds. The model accurately predicts the transient nystagmus that would be expected: its direction, duration, phase velocity and even the brief secondary nystagmus which is characteristic of adaptation to constant velocity rotation. VOR also allows the user to define end organ condition configurations, e.g. "normal", "bilateral vestibular loss", "unilateral superior neuritis", which are represented as a series of response gains attached to the sensory inputs from each end organ, relative to a nominal perfect gain of 1, and various other parameters which are derived from the human vestibular system, including the rate of drift of gaze to fixation point in light and dark, the rate at which the end organs adapt to constant stimuli, and quick-phase trigger dependencies. The VOR is not the only source of eye movement while attempting to maintain gaze on a fixation point. In our model, eye position drifts towards the fixation point at a nominal fixed rate. If this slow drift is insufficient to maintain gaze on the fixation point, a saccade or quick phase is triggered. Hence the transduction of mechanical forces at the labyrinths into sensory signals, subject to end organ conditions and adaptation that reduce the strength of the neuronal signals, maintain the RHP. Eye movement is then determined entirely by (a) the direction from RHP to the (world-referenced) fixation point, and (b) the disparity between eye direction and actual fixation point (which may be head-referenced). To validate the model, we prepared 24 motion profile/end organ condition combinations, compared the outputs from our model with real world observations, and found the results to be similar. Similarities include a simple first approximation of the linear and angular VOR; nystagmus caused by a subject's attempts to maintain fixation on a head-referenced target during head movement; decay of nystagmus through adaptation to stimulus, including secondary nystagmus; indefinitely prolonged nystagmus during off-vertical axis rotation (OVAR); rapid decay of nystagmus during the "tilt dump" motion profile, and dynamic cyclovergence during vertical linear acceleration. VOR is programmed in Objective-C using Xcode and runs on the Apple iPad. Its screen displays a 3d graphical representation of the virtual subject's head and eyes, including imaginary lines of sight to clarify eye movements. The user may program an effectively unlimited series of linear and angular motions of the rotating chair, and of the virtual subject's head relative to the chair. They may also program the gain (roughly, the sensitivity) associated with each end organ and other variables relating to the subject. They may select a series of internal variables to chart during the motion profile such as head velocity, eye direction, neuron firing rates, etc., while simultaneously displaying the head and eyes. VOR can record a video screen capture of the virtual head, eyes and lines of sight during the execution of a motion profile, a CSV file containing the internal variables at each time interval, a PNG image of the labelled chart, PDF descriptions of the motion profile and end organ condition configurations, and data files defining the motion profiles and end organ conditions which can then be exchanged between researchers/clinicians. Predefined motion profiles include: lateral, LARP and RALP head impulses; lateral head impulse with close fixation point; sinusoidal yaw, on-centre rotation, linear heave along Y axis, linear oscillation along X, Y and Z axes; linear sled along Y axis; forward- and backward-facing centrifugation; off-vertical axis rotation; tilt dump; and head tilt. Predefined conditions include: normal; left unilateral vestibular loss; bilateral vestibular loss; left superior neuritis; and "perfect" (unrealistic gain of 1 in otoliths, producing perfect linear VOR). All of these motion profiles and conditions may easily be modified, created and shared

    Gender-specific effects of raising Year-1 standards on medical students' academic performance and stress levels

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    Context: Medical schools are challenged to create academic environments that stimulate students to improve their study progress without compromising their well-being. Objectives: This prospective comparative cohort study investigated the effects of raising Year-1 standards on academic performance and on students' chronic psychological and biological stress levels. Methods: In a Dutch medical school, students within the last Bachelor's degree cohort (n = 410) exposed to the 40/60 (67%) credit Year-1 standard (67%-credit cohort) were compared with students within the first cohort (n = 413) exposed to a 60/60 (100%) credit standard (100%-credit cohort). Main outcome measures were Year-1 pass rate (academic performance), mean score on the Perceived Stress Scale (PSS, psychological stress) and hair cortisol concentration (HCC, biological stress). Results: Year-1 pass rates were significantly higher in the 100%-credit cohort (odds ratio [OR] 4.65). Interestingly, there was a significant interaction effect (OR 0.46), indicating that raising the standard was more effective for male than for female students. PSS scores (n = 234 [response rate [RR]: 57%] and n = 244 [RR: 59%] in the 67%- and 100%-credit cohorts, respectively) were also significantly higher in the 100%-credit cohort (F(1,474) = 15.08, P <.001). This applied specifically to female students in the 100%-credit cohort. Levels of HCC (n = 181 [RR: 44%] and n = 162 [RR: 39%] respectively) did not differ between co

    The (cost) effectiveness of a very low-energy diet intervention with the use of eHealth in patients with type 2 diabetes and obesity:study protocol for a randomised controlled non-inferiority trial (E-diet trial)

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    BACKGROUND: Despite preventive measures, the number of people with type 2 diabetes and obesity is increasing. Obesity increases morbidity and mortality in people with type 2 diabetes, making weight loss a cornerstone of treatment. We previously developed a very low energy diet (VLED) intervention that effectively reduced weight in people with type 2 diabetes in the long term. However, this intervention requires considerable time and manpower, which reduces the number of people who can benefit from it. eHealth offers more efficient solutions but has proven to be less effective than face-to-face interventions. Therefore, we want to investigate whether a blended version of our VLED intervention (in which face-to-face contact is partly replaced by an eHealth (mobile) application (E-VLED)) would be more cost-effective than the current face-to-face intervention. METHODS: We will conduct a randomised, controlled trial with non-inferiority design in patients with type 2 diabetes and obesity (BMI &gt; 30 kg/m2), aged 18-75 years. The control group will receive the usual care VLED intervention, while the intervention group will receive the E-VLED intervention for 1 year, where face-to-face contact will be partly replaced by an eHealth (mobile) application. The main study endpoint is the difference in weight (% change) between the control and intervention group after 1 year, plus the difference between the total costs (euro) of the treatment in the control and intervention groups. The secondary aims are to investigate the effectiveness of the E-VLED diet intervention regarding cardiovascular risk factors, quality of life, patient satisfaction, compliance, and to study whether there is a difference in effectiveness in pre-specified subgroups. General linear models for repeated measurements will be applied for the statistical analysis of the data. DISCUSSION: We hypothesise that the E-VLED intervention will be equally effective compared to the usual care VLED but lower in costs due to less time invested by the dietician. This will enable to help more people with type 2 diabetes and obesity to effectively lose weight and improve their health-related quality of life. TRIAL REGISTRATION: Netherlands Trial Register, NL7832, registered on 26 June 2019.</p

    The Effect of Including eHealth in Dietary Interventions for Patients with Type 2 Diabetes with Overweight or Obesity:A Systematic Review

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    eHealth has a growing impact on the delivery of healthcare, making health systems more efficient. This study examined the effect of dietary interventions using eHealth compared to face-to-face contact in patients with (pre-) type 2 diabetes (T2D) and who are overweight/obese. Literature databases were searched upon November 2022. Inclusion criteria: randomized controlled trial; duration ≄ 6 months; involving dietary interventions; performed in adults with (pre-) T2D and who are overweight/obese; using eHealth compared to face-to-face contact; and report outcomes on weight loss, glycemic regulation, and/or cost-effectiveness. Selection of articles was performed manually and using ASReviewLab. Fifteen studies were included for data extraction, investigating a wide variety of eHealth interventions. Seven studies reporting on weight loss showed a significant between-group difference (−1.18 to −5.5 kg); five studies showed a trend in favor of the eHealth programs. Eleven studies reported on HbA1c; three found a significant between-group difference (−0.23 to −0.70%) in favor of the eHealth programs and six studies showed non-significant improvements. Interaction with healthcare professionals led to better results of the dietary interventions. Two studies reported incomplete data on cost-effectiveness. In conclusion, eHealth shows better results of dietary interventions in (pre-) T2D patients compared to face-to-face, especially when combined with interaction with healthcare professionals.</p

    Septal ablation in hypertrophic obstructive cardiomyopathy improves systolic myocardial function in the lateral (free wall): a follow-up study using CMR tissue tagging and 3D strain analysis

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    Aims: Alcohol septal ablation (ASA) has been successful in the treatment of symptomatic hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study is to evaluate the effects of ethanol-induced myocardial infarcts on regional myocardial function using cardiac magnetic resonance (CMR) tissue tagging and 3-dimensional (3D) strain analysis. Methods and results: In nine patients (age 52±15 years) who underwent ASA, CMR was performed prior to and 6 months after the procedure. Regional myocardial mass was evaluated using cine imaging. Myocardial tagging was used to calculate systolic 3D myocardial strain values. These strain values were used to calculate the shortening index (SI), a robust parameter for myocardial contraction. Maximum end-systolic (ES) SI and systolic SI rate were quantified in three circumferential segments: septum, adjacent, and remote (lateral) myocardium. Compared with baseline, septal and non-septal mass decreased at follow-up (from 72±27 to 59±21 g; P=0.008 and from 131±34 to 109±30 g; P=0.008, respectively). In the septum, maximum ES SI and SI rate remained unchanged after ASA. In adjacent myocardium, ES SI remained unchanged, whereas SI rate improved (from -56.5±21.1 to -70.0±16.7%/s; P=0.02). Both ES SI and SI rate improved significantly in remote myocardium (from -16.9±2.8 to -18.8±3.2%; P=0.02 and from -70.3±9.2 to -86.1±15.0%/s; P=0.01, respectively). Conclusion: Reduction of left ventricular (LV) outflow tract obstruction in symptomatic HOCM is associated with a significant reduction in myocardial mass and improvement of intramural systolic function in the lateral (remote) wall, indicating reversed LV remodelling. © The European Society of Cardiology 2006. All rights reserved

    Hair glucocorticoids in adults with intellectual disabilities and depressive symptoms pre- and post-bright light therapy:First explorations

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    BACKGROUND: Depressive symptoms and stress are common in adults with intellectual disabilities. Our aim was to explore long‐term biological stress levels, assessed by hair cortisol (HairF) and cortisone (HairE) concentrations, in adults with intellectual disabilities and depressive symptoms and to investigate the effects of bright light therapy (BLT) on hair glucocorticoids. METHOD: Scalp hair samples (n = 14) were retrospectively examined at baseline and post‐BLT (10.000 and 300 lux). Liquid chromatography–tandem mass spectrometry was used to measure hair glucocorticoids. RESULTS: A significant correlation was found between baseline HairF and depression scores (r = .605, p = .028). Post‐intervention HairE levels were significantly increased ([95% CI: 11.2–17.4 pg/mg], p = .003), in particular after dim light (300 lux) ([95% CI: 10.0–18.3 pg/mg], p = .020). CONCLUSIONS: This study showed that retrospectively examining biological levels of stress in adults with intellectual disabilities seems a potentially promising and objective method to gain insight in the stress level of adults with intellectual disabilities
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