Day-to-day Variation (day-to-day + variation)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


Day-to-Day Variation of the Urine Protein: Creatinine Ratio in Female Dogs with Stable Glomerular Proteinuria Caused by X-Linked Hereditary Nephropathy

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2007
Mary B. Nabity
Background:Interpretation of serial urine protein: creatinine (UPC) values is confounded by a lack of data regarding random biologic variation of UPC values in dogs with stable glomerular proteinuria. Hypothesis:That there is minimal day-to-day variability in the UPC of dogs with unchanging proteinuria and the number of measurements needed to reliably estimate UPC varies with the magnitude of proteinuria. Animals:Forty-eight heterozygous (carrier) female dogs with X-linked hereditary nephropathy (XLHN) causing stable proteinuria. Methods:Urine samples were obtained daily by cystocentesis for 3 consecutive days on 183 occasions (549 samples). The UPC was measured for each sample with a single dry-film chemistry auto-analyzer. Data were analyzed retrospectively by a power of the mean model because the variance of UPC values within the 3-day evaluation periods increased as the magnitude of proteinuria increased. Results:To demonstrate a significant difference (P < .05) between serial values in these proteinuric dogs, the UPC must change by at least 35% at high UPC values (near 12) and 80% at low UPC values (near 0.5). One measurement is adequate to reliably estimate the UPC when UPC < 4, but 2,5 determinations are necessary at higher UPC values. Conclusions and Clinical Importance: These guidelines for interpretation of serial UPC values in female dogs with XLHN may also be helpful for interpretation of UPC values in dogs with other glomerulopathies. [source]


Multiple mealtime administration of biphasic insulin aspart 30 versus traditional basal-bolus human insulin treatment in patients with type 1 diabetes

DIABETES OBESITY & METABOLISM, Issue 6 2006
J. -W.
Aim:, The aim of this study was to compare the effect of multiple mealtime injections of biphasic insulin aspart 30 (30% fast-acting insulin aspart in the formulation, BIAsp30) to traditional basal-bolus human insulin regimen (HI) on glycaemic control in patients with type 1 diabetes. Methods:, Twenty-three patients (eight women and 15 men) aged 44.8 (20.6,62.5) years (median and range) with a diabetes duration of 19.5 (1.6,44.6) years completed the study. All eligible patients were randomly assigned to BIAsp30 thrice daily supplied with bedtime NPH insulin when necessary, or basal-bolus HI for 12 weeks and then switched to the alternative regimen for another 12 weeks. The insulin dose adjustments were made by patients on the basis of advice from a diabetes nurse. At end of each treatment period, the patients attended two profile days, 1 week apart for pharmacodynamic and pharmacokinetic assessments. HbA1C was measured at baseline and at the end of each treatment period. A seven-point self-monitored blood glucose (SMBG) was obtained twice weekly. Results:, In comparison with HI, multiple mealtime injections of BIAsp30 resulted in a significant reduction in HbA1C[HI vs. BIAsp30 (%, geometric mean and range): 8.6 (7.4,11.4) vs. 8.3 (6.7,9.8), p = 0.013]. During treatment with BIAsp30, nighttime glycaemic control was significantly improved. Day-to-day variation in pharmacodynamics and pharmacokinetics and the rate of hypoglycaemia were not increased with BIAsp30 compared with HI. Conclusions:, In type 1 diabetics, multiple mealtime administration of BIAsp30 compared with traditional basal-bolus human insulin treatment significantly improves long-term glycaemic control without increasing the risk of hypoglycaemia. Despite a higher proportion of intermediate-acting insulin, thrice-daily injections with BIAsp30 do not increase the day-to-day variations in insulin pharmacokinetics and pharmacodynamics. [source]


Insulin analogues: have they changed insulin treatment and improved glycaemic control?

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2002
Sten Madsbad
Abstract To improve insulin therapy, new insulin analogues have been developed. Two fast-acting analogues with a more rapid onset of effect and a shorter duration of action combined with a low day-to-day variation in absorption rate are now available. Despite this favourable time,action profile most studies have not been able to show any improvement in overall glycaemic control with the fast-acting analogues. A reduced post-prandial increase in blood glucose has been found in all studies, whereas between 3 and 5,h after the meal and during the night an increased blood glucose level is the normal course. This is probably the main explanation for the absence of improvement in overall glycaemic control when compared with regular human insulin. A tendency to a reduction in hypoglycaemic events during treatment with fast-acting analogues has been observed in most studies. Recent studies have indicated that NPH insulin administered several times daily at mealtimes can improve glycaemic control without increasing the risk of hypoglycaemia. The fast-acting analogues are now also available as insulin mixed with NPH. Insulin glargine is a new long-acting insulin which is soluble and precipitates after injection, resulting in a long half-life with a residual activity of about 50% 24,h after injection. Insulin glargine is a peakless insulin and studies in both type 1 and type 2 diabetic patients indicate that glargine improves fasting blood glucose control and reduces the incidence of nocturnal hypoglycaemia. Surprisingly, the new fast,acting analogues have not achieved the expected commercial success, which emphasises the need for new strategies for basal insulin supplementation, exercise, diet and blood glucose monitoring. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Evaluating the power of monitoring plot designs for detecting long-term trends in the numbers of common guillemots

JOURNAL OF APPLIED ECOLOGY, Issue 3 2006
MICHELLE SIMS
Summary 1In recent years concerns have been raised regarding the status of the common guillemot Uria aalge in the UK. Numbers have declined in several regions, highlighting the need for continued monitoring of this internationally important population. However, the extent to which the current monitoring scheme is capable of detecting declines and options for improving efficiency has received little attention. 2We investigated the power of different monitoring design options for detecting long-term trends in abundance at a colony of guillemots. The ability to detect trends in abundance was reduced by the large temporal and spatial variability in colony attendance. Taking a linear mixed model approach, we obtained details on the sources and sizes of the variance components using count data collected from monitoring plots on the Isle of May, Scotland, and assessed how best to allocate sampling effort in the light of the count variability structure. 3Our results indicated that trend detection will be improved by counting birds in more plots rather than by increasing the number of counts at existing plots. 4The revisit pattern of counts at the monitoring plots during the seasonal counting period had little effect on trend detection power. However, given the practical issues associated with counting guillemots, alternative revisit patterns to the current approach are preferred. 5For a fixed number of visits per plot, power is strongly influenced by the choice of revisit design if the day-to-day variation in colony attendance is increased. 6Synthesis and applications. Aspects of the UK seabird monitoring scheme can be improved. Changes to the allocation of sampling effort and the plot-revisit pattern will improve both the statistical power to detect long-term trends and the efficiency of conducting the survey. We stress the importance of considering the structure and magnitude of the count variation in a power analysis because judicious design decisions depend on the relative magnitude of these variance components. [source]


Daily interpersonal events in pain patients: Applying action theory to chronic illness

JOURNAL OF CLINICAL PSYCHOLOGY, Issue 9 2006
Mary C. Davis
Action theory proposes that individuals actively shape and then respond to their environments, highlighting the role of stable person characteristics in the development and maintenance of life's interpersonal difficulties. In this study, the authors adopt the action perspective in their examination of predictors of daily interpersonal events among chronic pain patients with rheumatoid arthritis. They probe the extent to which stable symptoms of illness explained between-person variation, and fluctuating symptoms explain day-to-day variation in both positive and negative events. Their evaluation of patients' daily diary reports indicate that between-person differences accounted for more variance in the occurrence of positive events relative to negative events (48% vs. 31%, respectively). Likewise, between-person factors accounted for more variance in appraisals of positive compared to negative events across relationship domains. Both intractable illness symptoms and disability, and daily fluctuations in pain and fatigue, were only weakly related to patients' reports of their interpersonal experiences. Consistent with action theory, these results suggest that stable person characteristics are strongly related to daily stressors and particularly daily positive events in pain patients, but still account for less than 50% of the variance in events and their appraisals. In contrast, elevations in illness-related features, both between individuals and within individuals from day-to-day, are not robust predictors of positive or negative social exchanges. These findings point to the value of capturing the experiences of individuals intensively over time, an approach that can help to elaborate the contributions of both stable factors and circumstance in shaping social contexts in chronic illness. © 2006 Wiley Periodicals, Inc. J Clin Psychol 62: 1097,1113, 2006. [source]


Prospective comparison of subjective arousal during the pre-sleep period in primary sleep-onset insomnia and normal sleepers

JOURNAL OF SLEEP RESEARCH, Issue 2 2007
JENNIFER A. ROBERTSON
Summary Psychophysiological insomnia (PI) is the most common insomnia subtype, representing 12,15% of all sleep centre referrals. Diagnostic guidelines describe PI as an intrinsic sleep disorder involving both hyperarousal and learned sleep-preventing associations. Whilst evidence for the first component is reasonably compelling, evidence for learned (conditioned) sleep effects is markedly lacking. Indeed, to date no study has attempted to capture directly the conditioned arousal effect assumed to characterize the disorder. Accordingly, the present study explored variations in subjective arousal over time in 15 PI participants (sleep onset type) and 15 normal sleepers (NS). Self-report measures of cognitive arousal, somatic arousal and sleepiness were taken at three time points: 3 h before bedtime (early to mid-evening); 1 h before bedtime (late evening); and in the bedroom at lights out (bedtime) across four, 24-h cycles. Fluctuations in mean arousal and sleepiness values, and in day-to-day variation were examined using analyses of variance. Participants with PI were significantly more cognitive aroused and significantly less sleepy relative to NS, within the bedroom environment. These results support the tenet of conditioned mental arousal to the bedroom, although competing explanations cannot be ruled out. Results are discussed with reference to extant insomnia models. [source]


Acrylamide levels in Finnish foodstuffs analysed with liquid chromatography tandem mass spectrometry

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2007
Susanna Eerola
Abstract Sample clean-up and HPLC with tandem mass spectrometric detection (LC-MS/MS) was validated for the routine analysis of acrylamide in various foodstuffs. The method used proved to be reliable and the detection limit for routine monitoring was sensitive enough for foods and drinks (38 ,g/kg for foods and 5 ,g/L for drinks). The RSDs for repeatability and day-to-day variation were below 15% in all food matrices. Two hundred and one samples which included more than 30 different types of food and foods manufactured and prepared in various ways were analysed. The main types of food analysed were potato and cereal-based foods, processed foods (pizza, minced beef meat, meat balls, chicken nuggets, potato-ham casserole and fried bacon) and coffee. Acrylamide was detected at levels, ranging from nondetectable to 1480 ,g/kg level in solid food, with crisp bread exhibiting the highest levels. In drinks, the highest value (29 ,g/L) was found in regular coffee drinks. [source]


Does severity of Parkinson's disease vary according to season?

MOVEMENT DISORDERS, Issue 4 2005
Ronald B. Postuma MD
Abstract In temperate climates, many factors that may influence function in Parkinson's disease (PD) vary according to season. We examined whether severity of PD, as measured by the Unified Parkinson's Disease Rating Scale (UPDRS), varied with the season of evaluation. We found no evidence for seasonal fluctuation in the UPRDS scores, suggesting that, although considerable day-to-day variation may exist in PD, there is little monthly or seasonal variation. © 2004 Movement Disorder Society [source]


Circadian variation in resource quality: leaf water content and its relevance to eastern grey kangaroo Macropus giganteus and common wombat Vombatus ursinus

AUSTRAL ECOLOGY, Issue 2 2010
PETER J. JARMAN
Abstract Green leaves of six grass species in temperate Australia showed considerable circadian variation (especially in summer) in water content, which peaked late in the night and fell from sunrise to an afternoon minimum. In summer, water content of a set of ,wetter' species (Axonopus affinis, Pennisetum clandestinum and Paspalum dilatatum) was consistently higher and varied less profoundly through the 24 h than that of a ,drier' set (Imperata cylindrica, Poa labillardieri and Themeda triandra). Hour-to-hour and day-to-day variation in leaf water content of P. dilatatum in summer partly but imperfectly reflected ambient temperature. Recognizing the risks for herbivores of visiting water sources, we considered leaf water content as a source of free water for leaf-grazing herbivores, eastern grey kangaroos Macropus giganteus and common wombats Vombatus ursinus. Using known field metabolic rates, energy requirements and digestive efficiencies, we calculated these two species' free-water intakes when satisfying their energy needs with these grasses but distributing their grazing in different schedules. Both species would obtain more free water by their observed foraging schedules than by random or daytime-only schedules. We calculated that the measured grasses could satisfy the water requirements of wombats but not always those of kangaroos, who would need to drink when forage water content was less than about 70%. Water content of grass leaf could rise above and fall below this value within a day, creating some scope for kangaroos to manage their need to visit water by adjusting foraging schedules or choice of grass species. In future studies, circadian variation in leaf water content should be considered as a factor (together with their thermal physiology) driving herbivores' activity scheduling, and affecting their dietary selection. [source]


Direct determination of nucleosides in the urine of patients with breast cancer using column-switching liquid chromatography,tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 11 2006
Sung-Hee Cho
Abstract We developed an analytical method for a simple, sensitive and simultaneous determination of oxidized nucleosides in urine using column-switching liquid chromatography,electrospray/tandem mass spectrometry (LC-ESI/MS/MS). We connected two columns through a six-way switching valve and effectively separated nucleosides in the urine from the interference by column-switching liquid chromatography. We monitored separated nucleosides using positive ionization tandem mass spectrometry in selective reaction monitoring (SRM) mode. The calibration ranges of nucleosides were 0.2,100 nmol/mL. The linearity of the method was 0.994,0.999, and the limits-of-detection (LOD) at a signal-to-noise (S/N) ratio of 3 were 0.1,0.2 nmol/mL. The coefficients of variation were in the range 2.28,11.74% for within-day variation and 4.36,11.15% for day-to-day variation, respectively. To explore the relationship between breast cancer and the nucleosides level in human urine, we measured the concentrations of nucleosides in female patients with breast cancer (n = 30) and in normal female subjects (n = 30). The concentration of nucleosides was significantly increased in patients with breast cancer when compared with the normal controls (1-methyladenosine; p < 0.005, N2,N2 -dimethylguanosine; p < 0.01, 5-hydroxymethyl-2,-deoxyuridine; p < 0.001, 8-hydroxy-2-deoxyguanosine; p < 0.001). Therefore, the elevated levels of nucleosides could be used as an important biomarker for breast-cancer research. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Determination of both the time constant of v,O2 and ,v,O2/,W from a single incremental exercise test: validation and repeatability

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2004
Anita G. M. Wisén
Summary A single incremental cycle exercise test including a steady-state load, combined with respiratory gas exchange, was performed with the objective of determining the time constant (o2) and the amount of oxygen required at each load (o2/,W) by using a novel equation. The protocol was validated using four exercise tests at different constant loads and conventionally fitted mono-exponential functions to determine o2, and interpolation of o2 versus load to determine o2/,W. No significant differences were seen between the means of either o2 or o2/,W determined with the two protocols. The correlation coefficient was 0·62 for o2 and 0·48 for o2/,W. The absolute differences (2 SD) were 11·6 s for o2 and 1·1 ml min,1 W,1 for o2/,W. The equations were compared in the same steady-state test and good agreement of o2 was obtained (R = 0·99). The 5,6-week repeatability (incremental test) was evaluated. No statistical differences were seen between the mean of the repeated tests. The difference between the tests (2 SD) were 20 s for o2 and 1·2 ml min,1 W,1 for o2/,W. In conclusion, o2 and o2/,W can be determined from a single incremental test. The validation showed an acceptable agreement, although the variations in absolute values were not negligible. This could partly be explained by the natural day-to-day variation and fluctuations in incoming raw data. The test,retest variation in absolute values was considerable, which must be taken into account when using o2 and o2/,W for evaluation of aerobic function. [source]


Multiple mealtime administration of biphasic insulin aspart 30 versus traditional basal-bolus human insulin treatment in patients with type 1 diabetes

DIABETES OBESITY & METABOLISM, Issue 6 2006
J. -W.
Aim:, The aim of this study was to compare the effect of multiple mealtime injections of biphasic insulin aspart 30 (30% fast-acting insulin aspart in the formulation, BIAsp30) to traditional basal-bolus human insulin regimen (HI) on glycaemic control in patients with type 1 diabetes. Methods:, Twenty-three patients (eight women and 15 men) aged 44.8 (20.6,62.5) years (median and range) with a diabetes duration of 19.5 (1.6,44.6) years completed the study. All eligible patients were randomly assigned to BIAsp30 thrice daily supplied with bedtime NPH insulin when necessary, or basal-bolus HI for 12 weeks and then switched to the alternative regimen for another 12 weeks. The insulin dose adjustments were made by patients on the basis of advice from a diabetes nurse. At end of each treatment period, the patients attended two profile days, 1 week apart for pharmacodynamic and pharmacokinetic assessments. HbA1C was measured at baseline and at the end of each treatment period. A seven-point self-monitored blood glucose (SMBG) was obtained twice weekly. Results:, In comparison with HI, multiple mealtime injections of BIAsp30 resulted in a significant reduction in HbA1C[HI vs. BIAsp30 (%, geometric mean and range): 8.6 (7.4,11.4) vs. 8.3 (6.7,9.8), p = 0.013]. During treatment with BIAsp30, nighttime glycaemic control was significantly improved. Day-to-day variation in pharmacodynamics and pharmacokinetics and the rate of hypoglycaemia were not increased with BIAsp30 compared with HI. Conclusions:, In type 1 diabetics, multiple mealtime administration of BIAsp30 compared with traditional basal-bolus human insulin treatment significantly improves long-term glycaemic control without increasing the risk of hypoglycaemia. Despite a higher proportion of intermediate-acting insulin, thrice-daily injections with BIAsp30 do not increase the day-to-day variations in insulin pharmacokinetics and pharmacodynamics. [source]


Short-term effects of air pollution on cardiovascular diseases: outcomes and mechanisms

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2007
M. FRANCHINI
Summary. The effects of air pollution on health have been intensively studied in recent years. Acute exposure to environmental pollutants such as particulate and gaseous matters (carbon monoxide, nitrogen oxides, sulphur dioxide and ozone) was associated with an increased rate of events and mortality because of cardiovascular diseases. These effects were investigated in short-term studies, which related day-to-day variations in air pollution to disease, and in long-term studies, which have followed cohorts of exposed individuals over time. The evidence from the literature on the short-term cardiovascular effects of air pollutants is discussed from clinical and mechanistic points of view. [source]