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Varying Times (varying + time)
Selected AbstractsAssessment of blood pressure in patients with Type 2 diabetes: comparison between home blood pressure monitoring, clinic blood pressure measurement and 24-h ambulatory blood pressure monitoringDIABETIC MEDICINE, Issue 6 2001M. G. Masding Abstract Aims To compare a home blood pressure (BP) monitoring device and clinic BP measurement with 24-h ambulatory BP monitoring in patients with Type 2 diabetes mellitus (DM). Methods Fifty-five patients with type 2 DM had BP measured at three consecutive visits to the DM clinic by nurses using a stethoscope and mercury sphygmomanometer (CBP). Twenty-four-hour ambulatory BP was measured using a Spacelabs 90207 automatic cuff-oscillometric device (ABPM). Subjects were then instructed in how to use a Boots HEM 732B semiautomatic cuff-oscillometric home BP monitoring device and measured BP at home on three specified occasions on each of 4 consecutive days at varying times (HBPM). Results Correlations between HBPM and ABPM were r = 0.88, P < 0.001 for systolic BP and r = 0.76, P < 0.001 for diastolic BP, with correlations between CBP and ABPM being systolic r = 0.59, P < 0.001, diastolic r = 0.47, P < 0.001. HBPM agreed with ABPM more closely compared with CBP (CBP +10.9/+3.8 (95% confidence intervals (CI) 6.9, 14.8/1.6, 6.1) vs. HBPM +8.2/+3.7 (95% CI 6.0, 10.3/2.0, 5.4)). The sensitivity, specificity and positive predictive value of HBPM in detecting hypertension were 100%, 79% and 90%, respectively, compared with CBP (85%, 46% and 58%, respectively). Conclusions In patients with Type 2 DM, home BP monitoring is superior to clinic BP measurement, when compared with 24-h ambulatory BP, and allows better detection of hypertension. It would be a rational addition to the annual review process. Diabet. Med. 18, 431,437 (2001) [source] D2 Dopamine receptor blockade results in sprouting of DA axons in the intact animal but prevents sprouting following nigral lesionsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2003W. Tripanichkul Abstract Recently it was demonstrated that sprouting of dopaminergic neurons and a microglial and astrocyte response follows both partial lesions of the substantia nigra pars compacta and blockade of the D2 dopamine receptor. We therefore studied the effects of the combination of these two treatments (lesioning and D2 dopamine receptor blockade). Haloperidol administration caused a 57% increase in dopaminergic terminal tree size (measured as terminal density per substantia nigra pars compacta neuron) and an increase of glia in the striatum. Following small to medium nigral lesions (less than 60%), terminal tree size increased by 51% on average and returned density of dopaminergic terminals to normal. In contrast, administration of haloperidol for 16 weeks following lesioning resulted in reduced dopaminergic terminal density and terminal tree size (13%), consistent with absent or impaired sprouting. Glial cell numbers increased but were less than with lesions alone. When haloperidol was administered after the striatum had been reinnervated through sprouting (16,32 weeks after lesioning), terminal tree size increased up to 150%, similar to the effect of haloperidol in normal animals. By examining the effect of administering haloperidol at varying times following a lesion, we concluded that a switch in the effect of D2 dopamine receptor blockade occurred after dopaminergic synapses began to form in the striatum. We postulate that when synapses are present, D2 dopamine receptor blockade results in increased terminal density, whereas prior to synapse formation D2 dopamine receptor blockade causes attenuation of a sprouting response. We speculate that D2 dopamine receptors located on growth cones ,push' neurites toward their targets, and blockade of these receptors could lead to attenuation of sprouting. [source] Quantifying the impact of survivor treatment bias in observational studiesJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 6 2006Peter C. Austin PhD Abstract Rationale, Observational cohort studies are frequently used to measure the impact of therapies on the time to a particular outcome. Treatment often has a time-variant nature since it is frequently initiated at varying times during a patient's follow-up. Studies in the medical literature frequently ignore the time-dependent nature of treatment exposure. Survivor treatment bias can arise when the time dependent nature of treatment exposure is ignored since patients who survived to receive treatment may be healthier than patients who died prior to receipt of treatment. Aims and objectives, The objective of the current study was to explicitly quantify the magnitude of survivor-treatment bias. Methods, Monte Carlo simulations using parameters obtained from an analysis of patients admitted to hospital with a diagnosis of acute myocardial infarction in Ontario, Canada. Results and conclusions, When the true treatment was null (hazard ratio of 1), estimated treatment effects varied from a 4% reduction in mortality to a reduction in mortality of 27% when the time varying nature of the treatment was ignored. Furthermore, survivor-treatment bias increased as the time required foe exposed patients to receive treatment increased. Similarly, survivor treatment bias was amplified as exposure was defined to be exposure at any time prior to mortality compared to exposure within a fixed time interval starting at the time origin. Ignoring the time-dependent nature of treatment results in overly optimistic estimates of treatment effects. Depending on the period required for patients to initiate therapy, treatments with no effect on survival can appear to be strongly associated with improved survival. The current study is the first to explicitly quantify the magnitude of bias that results from ignoring the time-varying nature of treatment exposure in survival studies. [source] Age and ovariectomy impair both the normalization of mechanical properties and the accretion of mineral by the fracture callus in ratsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2001Ralph A. Meyer Jr. The impact of age and ovariectomy on the healing of femoral fractures was studied in three groups of female rats at 8, 32 and 50 weeks of age at fracture. In the two older groups, the rats had been subjected to ovariectomy or sham surgery at random at 26 weeks of age. At fracture, all rats received unilateral intramedullary pinning of one femur and a middiaphyseal fracture. Rigidity and breaking load of the femora were evaluated at varying times up to 24 weeks after fracture induction by three-point bending to failure. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. In the youngest group, 8-week-old female rats regained normal femoral rigidity and breaking load by 4 weeks after fracture. They exceeded normal contralateral values by 8 weeks after fracture. In the middle group, at 32 weeks of age, fractures were induced, and the femora were harvested at 6 and 12 weeks after fracture. At 6 weeks after fracture there was partial restoration of rigidity and breaking load. At 12 weeks after fracture, only the sham-operated rats had regained normal biomechanical values in their fractured femora, while the fractured femora of the ovariectomized rats remained significantly lower in both rigidity and breaking load. In contrast, for the oldest group of rats, 50 weeks old at fracture, neither sham-operated nor ovariectomized rats regained normal rigidity or breaking load in their fractured femora within the 24 weeks in which they were studied. In all fractured bones, there was a significant increase in BMD over the contralateral intact femora due to the increased bone tissue and bone mineral in the fracture callus. Ovariectomy significantly reduced the BMD of the intact femora and also reduced the gain in BMD by the fractured femora. In conclusion, age and ovariectomy significantly impair the process of fracture healing in female rats as judged by measurements of rigidity and breaking load in three-point bending and by accretion of mineral into the fracture callus. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Assessment of treatment response in mania: commentary and new findingsBIPOLAR DISORDERS, Issue 2 2003Ross J Baldessarini Background:, Assessment of therapeutic interventions in bipolar disorder is complicated by rapid, complex clinical changes, high placebo-response rates, and varying times to specific levels of clinical recovery that may not be adequately reflected in averaged rating-scale scores particularly in acute mania, calling for improved methods to evaluate treatment responses. Chengappa et al. (1) propose operational criteria for specific outcomes based on rating-scale data from two placebo-controlled trials of olanzapine in mania. Methods:, These trials and other recent research were considered in commenting on the design, conduct, analysis and interpretation of experimental therapeutic trials in mania and to optimize olanzapine versus placebo contrasts by systematically varying end-point criteria for mania (YMRS) and depression (HDRS) ratings. Results:, Olanzapine versus placebo responses were optimally separated at scores of 10 for final paired mania and depression ratings, or 5 for each rating scale considered separately. Conclusions:, Use of empirically determined end-points derived from standard rating scales used in experimental therapeutics research in mood disorders can improve both outcome-assessment and separation of active treatment from placebo responses in acute mania. [source] | |||||||||||||