Search

Radial variations in wood mineral element concentrations (N, P, Ca, Mg, K, Mn, Al) were investigated in 5 oak trees (a ring-porous species with typical heartwood) and 5 beech trees (a diffuse-porous to semi-ring porous wood species lacking typical heartwood) growing on an ochreous brown earth in the Belgian Ardennes. Differences in concentration profiles were consistent with the difference in wood structure. Specifically, oak had markedly higher concentrations in sapwood, suggesting that nutrients are actively resorbed from senescing wood rings, resulting in very low elemental concentrations in heartwood. Similarities between the two species, including outwardly decreasing cation concentrations and a recent increase in Al concentration, might be ascribed to a common environmental influence, i.e. soil leaching by acid rain. However, the decrease in Mn concentration in both species is not consistent with a scenario of decreasing soil pH. Alternative explanations are discussed., info:eu-repo/semantics/published

Background: While age-related increases of between-person variability in a variety of cognitive measures are commonly reported in cross-sectional studies, the nature of short-term intraindividual fluctuation in elderly people’s performance is relatively unexplored. Objective: The goal of the present study is to examine short-term fluctuations in elderly people’s sensorimotor functioning and their relations to individual differences in verbal and spatial memory. Methods: Fluctuations in old adults’ (mean = 75.71 years, SD = 6.93 years) sensorimotor performance were investigated by biweekly measurements spanning approximately 7 months. Sensorimotor performance was measured by three walking tasks, including the duration and the number of steps taken to walk a 360-degree circle and to walk 10 feet both at normal and fast pace. Performances of verbal and spatial memory were assessed by weekly measurements of digit memory span, memory for short text and spatial recognition. Results: The magnitude of intraindividual fluctuation in most sensorimotor and memory tasks examined was at least half as great as the level of individual differences across persons. In addition, intraindividual fluctuation in sensorimotor performance is a relatively stable individual attribute, which correlates positively with age and negatively with the levels of sensorimotor, text and spatial memory performance. Although a substantial amount of individual differences in intraindividual fluctuation was shared with mean performance level, variance component and hierarchical regression analyses showed that intraindividual fluctuation in walking steps added significant independent contribution over and above that given by level of performance in predicting text and spatial memory. Conclusion: Taking these results together, we suggest that intraindividual fluctuations in elderly people’s performance should not be ignored or simply treated as measurement error; rather, they are potentially important empirical variables for understanding sensory and cognitive aging and the nature of intraindividual response variations in general.

Objectives: Normative values of the masseter reflex are scarce. We studied the latencies, amplitudes and side differences of the masseter reflex in 105 healthy volunteers between the ages of 5 and 78 years. Methods: Latencies were calculated as the mean of 10 single sweeps and, simultaneously, measured from the summation curve. Short-term reproducibility was determined in 33 volunteers by retesting the reflex after 1 week. Results: There was a positive correlation between age and latencies and a negative correlation between age and amplitude. Maximal normal latencies were 8.3 ms for men and 7.9 ms for women in the age group below 50 years and 9.1 and 9.2 ms for the age group above 50 years. Latency differences between the right and left sides of >0.4 ms for subjects aged below 50 years and >0.5 ms for subjects aged above 50 years exceeded the 95% confidence interval. Amplitudes did not depend on gender. Calculated as a percentage of the side with higher amplitude, differences above one third could be accepted as abnormal. Conclusion: The masseter reflex appears to be a stable and robust clinical test, if age and gender differences are taken into account.

Microincision cataract surgery (MICS) has been shown to induce less astigmatism.1 We compared the changes in corneal shape in each patient with an intraindividual comparison of each Zernike corneal aberrations and studied the correlation between pre- and postoperative aberrometric measurements, hoping to evaluate corneal integrity after MICS. This prospective clinical study included 29 consecutive eyes with 1.8 mm MICS (same surgeon, PJP). Exclusion criteria were a previous ocular surgery, central endothelial cell count less than 1800 cells/mm2, ocular surface pathology, glaucoma or topical treatment. Two limbal incisions of 1.8 mm (at the 10.30 o'clock position) and 1 mm (at 2 o'clock) were created with a steel blade. A 5 mm continuous curvilinear capsulorhexis was done, and the nucleus was removed with a 0.95 mm 30° angled tip, using a continuous ultrasound setting (Stellaris, Bausch …

Hintergrund. Die Biokompatibilitat von Intraokularlinsen aus unterschiedlichen faltbaren Materialien (hochrefraktives Silikon- und hydrophobes Acrylatmaterial) sollte im intraindividuellen Vergleich untersucht werden. Material und Methoden. In einer prospektiven, randomisierten Studie wurden 35 Patienten beidseits mittels selbstdichtender Tunnelinzision und Phakoemulsifikation operiert. Nach Randomisierung wurde in ein Auge eine faltbare Intraokularlinse mit 6-mm-Optik aus hochrefraktivem Silikon (Allergan SI40NB) und in das andere eine faltbare Intraokularlinse mit 6-mm-Optik aus hydrophobem Acrylatmaterial (Alcon Acrysof MA60BM) implantiert. Postoperative Kontrolluntersuchungen fanden nach 7 Tagen, 1–3 und 6 Monaten sowie 1 Jahr statt. Ergebnisse. Die Patienten erreichten nach 1–3 Monaten ein bestkorrigiertes Sehvermogen von 0,9±0,12/0,89±0,13 (SI40NB/MA60BM), dieses lag nach 1 Jahr bei 0,9±0,12/0,87±0,14 (SI40NB/MA60BM). Es zeigte sich kein signifikanter Unterschied beim errmittelten Endothelzellverlust. Die Laserflare-Werte (photon counts/ms) stiegen nur im fruhpostoperativen Bereich (7 Tage) geringfugig an (SI40NB/MA60BM: 14,2±8,68/15,49±7,2; statistisch nicht signifikant). Nach 3 Monaten lagen diese Werte wieder im Normbereich. Die mittlere Dezentrierung (in mm) lag 1 Jahr postoperativ bei 0,29±0,14/0,3±0,15 (SI40NB/MA60BM). Vierzig Prozent der MA60BM-IOLs zeigten in der Scheimpflug-Spaltaufnahme “Glistenings”. Nach 1 Jahr wurde kein signifikanter Unterschied in der Nachstarbildung (Scheimpflug-Analyse) gefunden. Schlussfolgerung. Ein Jahr nach der Implantation faltbarer hochrefraktiver Silikon- und hydrophober Acrylatintraokularlinsen uber eine Tunnelinzision nach Phakoemulsifikation ergaben sich hinsichtlich funktioneller und morphologischer Aspekte im intraindividuellen Vergleich zufrieden stellende Resultate ohne signifikante klinische Unterschiede zwischen den beiden faltbaren IOL.

A considerable number of physiological functions are known to show a gradual decline with increasing age. However, the effects of ageing differ widely between organ systems. It is believed that basal metabolic rate (BMR) falls dramatically with age. These observations, largely based on cross-sectional surveys, are discussed in light of our present understanding of the biology of ageing. This paper reviews both the longitudinal and cross-sectional studies of BMR and presents evidence that the fall in BMR with ageing may be less dramatic than previously perceived. Indeed, some subjects may show an increase in BMR with ageing. The mechanism of changes in BMR during ageing will be discussed. Organ weight changes appear to have a profound impact on BMR. The use of BMR to predict total energy expenditure in the 'old elderly' (>75 y) is unlikely to be of any practical use due to wide intra- and inter-individual variation in BMR. This wide intra- and inter-individual variation in BMR is due to illness, disease and other metabolic disorders seen in the elderly. Finally, the importance of measuring BMR in elderly populations for its use in clinical medicine will be discussed.

In unimanual reaction times (RT) to lateralized flashes, contralateral responses tend to be slower than ipsilateral responses. This has been called Crossed‐Uncrossed DiAerence (CUD). The CUD tends to show variability across subjects and across studies, but until now the stability of the CUD in an individual subject has not been investigated. To address the role of interand intra-subject variability in the CUD, three normal right handers were tested over 50 experimental sessions of 800 trials each, for a total of 40,000 trials of simple reaction times to lateralized flashes. In each subject, CUDs were computed for each session, over two, three, or more sessions, and over the entire dataset. These CUDs were then compared to the CUDs obtained in a group of 15 normal right handers, each tested once in a single session. Results show that: (i) CUD variability across several sessions in a single subject mimics the variability observed in a sample of subjects tested in a single session; (ii) this variability is considerably reduced when the CUD is computed over at least 2400 trials per subject; (iii) CUDs computed over 2400 and up to 12,000 of trials tend to be extremely similar (02 ms) across the three subjects tested here; (iv) when reaction times are ordered from the fastest to the slowest and divided into bins, the CUD is remarkably stable over the entire reaction time distribution; and (v) in contrast to the variability of the CUD, the variability for crossed and uncrossed responses across several sessions in a single subject is small and does not mimic the variability observed in a sample of subjects tested in a single session. Taken together, these data suggest that the intersubject variability in the CUD observed in single experimental sessions does not represent a reliable intersubject diAerence and that the CUD computed over thousands of trials reflects hard-wired mechanisms of callosal transmission. # 2000 Elsevier Science Ltd. All rights reserved.

Despite the availability of serial data on CA 125 in ovarian cancer, the problem of interpreting a change over time is still unsolved. Changes in marker concentrations are due not only to patients improving or deteriorating but also to analytical imprecision and normal intra-individual biological variation. The aim of this study was to assess the analytical imprecision (CV(A)) and the intra- and inter-individual biological variation (CV(I) and CV(G), respectively) of CA 125 in a group of 26 patients with clinically stable ovarian cancer. Furthermore, the critical difference for a change between two consecutive CA 125 concentrations calculated as square root(2) x Z x (CV(A)2 + CV(I)2)(1/2) (Z =1.65 for unidirectional and 1.96 for bidirectional changes, por = 0.05) and the index of individuality calculated as ((CV(A)2+CV(I)2)/CV(G)2)(1/2) were estimated. After the exclusion of outliers, CV(A) and the average CV(I) and CV(G) were 12.1%, 24.0%, and 43.1%, respectively. The index of individuality was 0.62 and the critical difference calculated for unidirectional changes was 62.6%. CV(A) and CV(I) contribute considerably to the variation in serial results and should, therefore, be included in the criteria for serum tumor marker assessment during monitoring of patients with ovarian cancer. The cut-off value of CA 125 is of minor value in detecting unusual results for an individual subject, when previous measurements from an individual are available. These measurements should be preferred as reference for interpretation of new results.

SummaryThis is the first report of a method to assess the significance of numerical changes in the platelet count based upon a result exceeding the normal intra-individual variation in platelet numbers. Serial platelet counts from 3,789 subjects were analysed to determine the intra-individual variation in platelet numbers. A platelet count difference of 98 × 109/L in males was found to represent a change that would occur by chance in less than 1 in 1,000 platelet count determinations. Tables to determine the significance of platelet number variations, given N previous observations, are provided at two probability levels. The repeatability of the platelet count was calculated as 0.871 (males) and 0.849 (females) indicating that the heritability of platelet count is high and that the platelet count is predominantly genetically determined. A seasonal variation in platelet count was found with a ‘winter’ versus ‘summer’ difference of 5.10 × 109/L (males) and 5.82 × 109/L (females).

Background: The gender of the observer may bias data. Objective: Compare the intra-observer agreements of male and female pediatric otolaryngologists about videotaped images of laryngeal papilloma. Design: Five male and six female pediatric otolaryngologists independently viewed videotapes of ten children undergoing treatment for laryngeal papilloma. Each of 12 anatomic sites was categorized as disease present, absent, or indeterminate. Each observer estimated the percent overall airway obstruction. 5–24 weeks later, each observer repeated his/her assessments. Results: The mean intra-observer agreements for both male and female pediatric otolaryngologists were good, and identical (κ 0.63; proportion of positive agreement 0.82; proportion of negative agreement 0.72). Females more frequently categorized a site as indeterminate. Males more frequently categorized a site oppositely on repeat assessment. The males’ indeterminate/opposite ratio was less than that of the females’ (P=0.03). Intra-observer estimates of overall airway obstruction have wide variability: for male pediatric otolaryngologists, differences exceeding 30% are significant; for females, 40%. Conclusions: Male and female pediatric otolaryngologists had equally good and identical intra-observer κ scores and proportions of positive and negative agreement. However, males used the indeterminate category less than did the females, and males more often gave an opposite categorization at the second viewing session. Estimates of overall airway obstruction have much intra-observer variability.

Objectives: (i) To examine the components of variation in nutrient intakes for older Korean adults; (ii) To calculate the level of accuracy with varying degree of precision in order to achieve estimates of usual nutrient intakes. Design: Five or six 24 h recalls were made over a four month period on each individual. Setting: A senior school from a middle-income, urban community in Inchon, Korea. Subjects: Forty-seven males and 36 females over 60 y old with complete records for at least five dietary recalls. Results: The within-person variation of nutrient intakes (21.8–103.2%) was higher and differed more markedly by nutrients than the between-person variation (9.4–63.7%). Males (2.26–11.28) showed larger within-to-between person variance ratios than females (1.73–5.86). The variance ratios were different by nutrients for males, but no such pattern was observed for females. Depending on nutrients, 5–6 recalls over a four month period gave estimates of nutrient intakes within 30–50% of usual intakes. For most nutrients, 100–200 subjects were sufficient to obtain estimates with 10% deviation of group usual intakes. Achieving r=0.9 between observed and usual intakes required 24–54 recalls for males and 8–23 recalls for females. Conclusions: The degree of precision achieved during assessment of older Korean adults' usual nutrient intakes changes with gender and by the type of nutrients. Achieving similar level of accuracy of the estimates, older Korean adults may require more dietary recalls than the adults in western countries. Sponsorship: Supported by the Korean Research Foundation and the Kyung Hee University Research Center.

BACKGROUND Distortion product otoacoustic emissions (DPOAEs) are evoked by simultaneously stimulating the cochlea with two tones. The DPOAE with the highest amplitude (at the frequency 2f1-f2) is usually used for routine audiological evaluation. Any interpretation of DPOAEs in a clinical setting must consider their intra- and intersubject variability. METHODS DPOAE measurements were performed in 36 normally hearing adults in three weekly test sessions. Each ear was tested twice per session, and the results were statistically analyzed. RESULTS All test candidates had measurable DPOAEs. Statistically significant differences in absolute DPOAE amplitudes were neither found between two measurements at the same day, nor at weekly intervals, nor between right and left ear of the same candidate. Absolute DPOAE amplitudes in women were significantly higher in the 2-6 kHz range whereas they presented with significantly lower amplitudes below 2 kHz when compared to men. CONCLUSIONS The present results indicate that monitoring of the inner ear status can be reliably performed using DPOAE measurements. Change in DPOAE amplitudes effectively indicate changes in the cochlear function with high sensitivity. Compared to TEOAE measurements, DPOAEs offer a higher frequency resolution in a broader frequency band and thus more detailed information about the cochlear condition.

Extrapolations of biological responses obtained in laboratory animals to human exposure conditions are commonly based on local particle deposition patterns. Although laboratory rats are frequently used in inhalation toxicology as human surrogates, their airway system exhibits a much more asymmetric branching pattern than that of the human lung. To investigate the effect of this structural difference on particle deposition, local particle deposition patterns were plotted as functions of three different morphometric parameters: airway generations, airway diameters, and cumulative pathlengths. Our search of the most appropriate morphometric parameter to characterize local particle deposition for extrapolation modeling purposes was based on two criteria: (i) the similarity of the distribution of deposited particles within the lungs, and (ii) the similarity of intrasubject variability in deposition in individual airways. The results presented in this paper suggest that airway diameters are a more appropriate morphometric parameter to classify local particle deposition patterns across the two species than the commonly used airway generations.

BACKGROUND: Acoustically evoked otoacoustic emissions are becoming increasingly significant in the clinical monitoring of cochlear function in adults. Any interpretation of these measurements in a clinical setting must consider their intra- and intersubject variability. METHODS: Transiently evoked otoacoustic emission (TEOAE) measurements were performed in 32 normally hearing adults in three weekly test sessions. Each ear was tested twice per session, and the results were statistically analyzed. RESULTS: All test candidates had measurable TEOAEs. Statistically significant differences in TEOAE amplitudes were neither found between two measurements at the same day, nor at weekly intervals. No statistically significant amplitude differences were found between right and left ear of the same candidate. TEOAE amplitudes in women were always higher than in men with statistically significant differences in the 2, 3, and 4 kHz frequency band. CONCLUSIONS: These results indicate that monitoring of the inner ear status can be reliably performed using TEOAE measurements. Changes in TEOAE amplitudes effectively indicate changes in the cochlear function.

Emotional stress testing was performed twice in 12 normotensive and 12 hypertensive patients. When compared with normotensive persons, hypertensive patients had a clearly greater adaptation of blood pressure response in second stress test. This effect was so pronounced that differences between normotensive and hypertensive persons observed in the first test disappeared. Because of this pronounced adaptation effect, demonstrated until now only for emotional stress, intraindividual comparison does not seem a method of choice in the evaluation of antihypertensive effects by stress situations. Specific influence of antihypertensive drugs on emotional blood pressure reactions can only be demonstrated in the inter-individual comparison with another antihypertensive drug. First comparison between both groups should only be done after establishing a therapeutic effect on resting blood pressure.

Background Intravascular ultrasound (IVUS) imaging can be used to optimize implantation of intracoronary stents; the variability of the measurements, however, remains unclear. Our aim in this study was to determine the intraobserver and interobserver variability of IVUS measurements after stent implantation. Methods Ninety-four patients underwent implantation of 100 Palmaz-Schatz stents in 98 lesions (79 de novo and 19 restenotic). IVUS measurements (3.5F, 30 MHz) of proximal and distal reference sections and of the smallest stent lumen were performed by 2 investigators. Results Intraobserver and interobserver correlations, respectively, were r = 0.96 and 0.93 for the proximal reference, r = 0.94 and 0.92 for the distal reference, and r = 0.97 and 0.97 for minimal stent lumen. Stent expansion (minimal lumen in the stent/mean reference area) showed a variability of r = 0.80 and 0.70. Taking a cutoff point of 90% for adequacy of stent expansion, observers agreed in only 77% whether the stent was adequately or inadequately expanded. Conclusions IVUS enables reproducible lumen measurements in stents and reference sections. The degree of stent expansion, however, underlies a high measurement variability that can lead to different therapeutic strategies. (Am Heart J 1999;137:368-71.)

Purpose. 1. To determine properties of the estimated variance component for the subject-by-formulation interaction (σ2 D) in investigations of individual bioequivalence (IBE), and 2. to evaluate the prevalence of interactions in replicate-design studies published by FDA. Methods. Four-period crossover studies evaluating IBE were simulated repeatedly. Generally, the true bioequivalence of the two formulations, including σ2 D= 0, was assumed, σ2 D was then estimated in a linear mixed-effect model by restricted maximum likelihood (REML). The same method was applied for estimating σ2 D for the data sets of FDA. Results. 1.σD estimated by REML was positively biased. The bias and dispersion of the estimated σDincreased approximately linearly with the estimated within-subject standard deviation for the reference formulation (σWR). Only a small proportion of the estimated σD exceeded the estimated σWR. 2. Distributions of the estimated σD were evaluated. At σWR = 0.30, a level of estimated σD= 0.15 was exceeded, by random chance, with a probability of about 25%. 3. Importantly, the behaviour of the σ2 D values estimated from the FDA data sets was similar to that exhibited by the simulated estimates of σ2 D which were generated under the conditions of true bioequivalence. Conclusions. 1. σD estimated by REML is biased; the bias increases proportionately with the estimated σWR. Consequently, exceeding a fixed level of σD (e.g., 0.15) does not indicate substantial interaction. 2. The data sets of FDA are compatible with the hypothesis of σ2 D = 0. Consequently, they do not demonstrate the prevalence of subject-by-formulation interaction. Therefore, it could be sufficient and reasonable to evaluate bioequivalence from 2-period crossover studies.

Grain mass (mg) and grain nitrogen concentration (%) were determined in 3,278 individual grains from eight cultivars with reference to the position of the grain on the head (spikelet number and floret number). Selected grains were removed from certain heads at anthesis. Grain nitrogen content (mg) was determined as the product of grain nitrogen concentration and grain mass. Grain mass and starch B-granule content were determined in 3,030 grains from a further 12 cultivars with reference to grain position, and selected grains were removed from certain heads at anthesis. Grains from distal florets were always smaller and had lower B-granule contents, nitrogen contents, and nitrogen concentrations than those from the two proximal florets on each spikelet, which were not significantly different from each other. Grains in the basal two spikelets of the head were smaller with lower nitrogen contents and higher B-granule contents than those in most of the head. Their nitrogen concentration, however, did...

Different mixed-effects models were compared to evaluate the population dose–response and relative potency of two albuterol inhalers. Bronchodilator response was measured after ascending doses of each inhaler in 37 asthmatic patients. A linear mixed-effects model was developed based on the approach proposed by Finney for the evaluation of bioassay data. A nonlinear mixed-effects (Emax) model with interindividual and interoccasion variability (IOV) in the different pharmacodynamic parameters was also fit to the data. Both methods produced a similar estimate of relative potency. However, the estimate of relative potency was 22% lower with the nonlinear mixed-effects model if IOV was not taken into account. Monte Carlo simulations based on a similar study design demonstrated that more biased and variable estimates of ED50and relative potency were obtained when the nonlinear mixed-effects model ignored the presence of IOV in the data. Furthermore, the linear mixed-effects model that did not account for IOV produced confidence intervals for relative potency that were too narrow and thus could lead to erroneous conclusions. These problems were avoided when the estimation model could account for IOV. Results of the simulations were consistent with those of the experimental data. Although the linear or the nonlinear mixed-effects model may be used to evaluate population dose–response and relative potency, there are important differences in the assumptions made by each method.

In this study we compared the amplitude, latency, and spatial distribution of the mismatch negativity (MMN), elicited by tones deviating in either frequency, intensity, stimulus-onset asynchrony (SOA) or location, and assessed inter- and intra-subject variability. Cross-dimensional comparisons were facilitated by adjusting the magnitude of deviance individually, so that the detection rates were similar, both across dimensions (within subject) and across subjects (within dimension). Despite similar detection rates, the MMN elicited by frequency deviance was larger, and the MMN elicited by SOA deviance was earlier than the other types of MMN. The reliability of frequency-related MMN was better than that of the other types of MMN. The results highlight the problems of comparing MMN across dimensions, especially in clinical populations.

Proposals are being made for changes in bioequivalence criteria, the so-called ‘population’ and ‘individual’ bioequivalence methodologies. The proposed criteria require assumptions that have not yet been validated, including the equality of intra-subject variances. More data are needed about the different sources of variation. This type of information was provided by a single dose, two-formulationf, our-period trial of phenytoin that used a replicated design. There were no formulation effects, thus each subject provided four observations fmm which intra-subject variances could be estimated; the individual intra-subject variances were equal within each formulation and were uncorrelated with individual means. This was true on both original and log-transformed scales. Observations of area under the time by concentration curve and maximum observed concentration were analyzed as the total study and within each of the two replications. Bioequivalence inferences were the same for all three analyses, indicating that for this drug ‘individual’ bioequivalence is not likely to be needed.

In 1992, the Division of Bioequivalence in the Office of Generic Drugs published a guide to Statistical procedures for bioequivalence studies using a standard two-treatments cross-over design (1). This paper describes the application of the guidelines to a practical protocol and the recent Proc MIXED (SAS®) will be shown to be much more convenient than the traditional Proc GLM for theoretical and practical reasons (correct estimation of residuals, analysis of the within-subjects variation, direct calculation of the Schuirmann 90% Confidence Intervals). This new procedure was applied to a study protocol on riluzole (Rilutek®) including a replicate design with the within-subject and between-subject variances being estimated on Cmax and AUC biopharmaceutic parameters.

La plupart des analgesiques sont elimines de l'organisme par biotransformation au niveau hepatique, le plus souvent consecutivement a une oxydation par les cytochromes P450. Compte tenu de la diversite de ce groupe d'enzymes et de l'importante variabilite inter- et intraindividuelle de leur activite, il est indispensable de connaitre avec precision les interactions existant entre les medicaments et les differentes isoenzymes. Les caracteristiques d'elimination des principaux groupes de medicaments utilises pour combattre les syndromes douloureux (AINS, paracetamol, opioides, antidepresseurs) sont passes en revue, tout comme les differents facteurs de variabilite (intrinseque, genetique et environnementale). Il s'avere qu'il est necessaire d'etre particulierement vigilant aux substances pouvant moduler la pharmacocinetique des analgesiques majeurs et, en cas d'utilisation des antidepresseurs, de faire preuve d'une certaine prudence, compte tenu de l'important potentiel inhibiteur de certains derives. Les facteurs genetiques sont egalement evoques, notamment l'incidence de certaines deficiences sur le metabolisme des medicaments. Grâce a une meilleure connaissance des facteurs de variabilite, il devrait etre possible pour les cliniciens d'anticiper un certain nombre de problemes pouvant aboutir a une toxicite ou au contraire a un echec therapeutique et ainsi d'ameliorer la prise en charge de leurs patients douloureux.

Cet article analyse les avantages et les inconvenients respectifs des trois principales methodes de mesure du flux de seve dans les arbres: les impulsions de chaleur, et les methodes a chauffage continu: bilan d'energie du xyleme (Cermak) et fluxmetre radial (Granier). Ces deux dernieres techniques sont utilisees en routine sur plusieurs sites dans le cadre du programme Euroflux, qui porte sur l'analyse et la modelisation des flux d'eau et de CO 2 au-dessus des forets europeennes. Ces deux methodes ont pu etre comparees sur les memes arbres, et ont donne des resultats tres proches. Les problemes majeurs dans l'utilisation de ces methodes sont lies aux modifications du signal par les gradients thermiques qui existent naturellement dans le tronc des arbres, et par les phenomenes de stockage et de transfert de la chaleur dans les tissus. En general, ces capteurs peuvent rester en place dans les troncs pendant une saison de vegetation, sans influence apparente sur les proprietes de transfert hydrique de la zone du xyleme mesuree. Les differentes sources de variabilite temporelle et spatiale des mesures de flux de seve sont discutees; on constate en general que la variabilite intraarbre est du meme ordre de grandeur que celle entre les arbres. La precision dans l'estimation de la transpiration a l'echelle de la parcelle depend de la taille de l'echantillon pour les mesures de flux et de la variable de changement d'echelle. Le nombre de capteurs de mesure a mettre en oeuvre pour avoir une estimation acceptable de la transpiration d'une population homogene est de l'ordre de 10, mais ce nombre peut augmenter selon l'espece etudiee, le type de tissu conducteur et avec l'heterogeneite de la parcelle. En conclusion, il est recommande, dans ces projets de recherche sur la mesure des flux d'eau et de carbone dans les ecosystemes forestiers, de combiner les mesures de flux de seve a la methode des correlations turbulentes, pour pouvoir separer la transpiration des arbres du flux total de vapeur d'eau, et pour analyser l'heterogeneite spatiale des flux hydriques dans les peuplements forestiers.

Werner's co-existence concept of development accounts for expectable and consistent between group differences in ontogenesis. A co-existence concept of development, rather than a replacement concept of development, also addresses variabilities within individual children and adults in the same domain. This study examined both “replacement” and “co-existence” concepts of development in the domain of illness. Both concepts of development accounted for the fact that no child exhibited abstract concepts of illness. However, only a co-existence concept of development can account for the fact that most college students demonstrated magical and concrete concepts of illness.

PURPOSE: (18)F-Fluorocholine (FCH) and (11)C-acetate (ACE) PET are widely used for detection of recurrent prostate cancer (PC). We present the first results of a comparative, prospective PET/CT study of both tracers evaluated in the same patients presenting with recurrence and low PSA to compare the diagnostic information provided by the two tracers. METHODS: The study group comprised 23 patients studied for a rising PSA level after radical prostatectomy (RP, 7 patients, PSA ≤ 3 ng/ml), curative radiotherapy (RT, 7 patients, PSA ≤ 5 ng/ml) or RP and salvage RT (9 patients, PSA ≤ 5 ng/ml). Both FCH and ACE PET/CT scans were performed in a random sequence a median of 4 days (range 0 to 11 days) apart. FCH PET/CT was started at injection (307 ± 16 MBq) with a 10-min dynamic acquisition of the prostate bed, followed by a whole-body PET scan and late (45 min) imaging of the pelvis. ACE PET/CT was performed as a double whole-body PET scan starting 5 and 22 min after injection (994 ± 72 MBq), and a late view (45 min) of the prostate bed. PET/CT scans were blindly reviewed by two independent pairs of two experienced nuclear medicine physicians, discordant subgroup results being discussed to reach a consensus for positive, negative end equivocal results. RESULTS: PET results were concordant in 88 out of 92 local, regional and distant findings (Cohen's kappa 0.929). In particular, results were concordant in all patients concerning local status, bone metastases and distant findings. Lymph-node results were concordant in 19 patients and different in 4 patients. On a per-patient basis results were concordant in 22 of 23 patients (14 positive, 5 negative and 3 equivocal). In only one patient was ACE PET/CT positive for nodal metastases while FCH PET/CT was overall negative; interestingly, the ACE-positive and FCH-negative lymph nodes became positive in a second FCH PET/CT scan performed a few months later. CONCLUSION: Overall, ACE and FCH PET/CT showed excellent concordance, on both a per-lesion and a per-patient basis, suggesting that both tracers perform equally for recurrent prostate cancer staging.

Background and Purpose Ultrasonography is increasingly used in vascular research, but there is limited information about the reproducibility of the ultrasound method for screening purposes. In this study the reproducibility of ultrasound assessment of carotid plaque occurrence, thickness, and morphology was examined within the setting of a population health survey. Methods In 1994/1995, 6720 participants in the Tromsø Study, Norway, underwent B-mode ultrasound scanning of the right carotid artery. The between- and within-sonographer reproducibility of ultrasound assessment of plaque occurrence and thickness was estimated by repeated scanning of a random sample of 107 participants. The between- and within-sonographer reproducibility of plaque morphology classification (echogenicity, four categories and heterogeneity, two categories) was determined by repeated reading of videotaped images of 119 randomly selected arteries with plaques. Results Between- and within-sonographer agreement on plaque occurrence was substantial with κ values (95% CI) of 0.72 (0.60 to 0.84) and 0.76 (0.63 to 0.89), respectively. Reproducibility of plaque thickness measurements was moderate, with mean absolute differences ranging between 0.25 and 0.55 mm (coefficients of variation between 13.8% and 22.4%). Agreement on plaque morphology classification was high, with κ values ranging between 0.54 and 0.73. Conclusions Population screening using B-mode ultrasound provides a valuable means for the detection and morphological evaluation of carotid plaques, whereas measurements of plaque thickness are subject to considerable measurement error.

The purpose of this study was to investigate whether MR angiography (MRA) of the portal venous system may be improved by means of superparamagnetic iron oxides (SPIOs) during accumulation phase imaging and to study the underlying contrast mechanisms. MRA of the portal venous system was performed on 48 patients before and after intravenous injection of a new SPIO (Resovist, Schering AG, Berlin, Germany). Resovist, as a predominantly liver parenchymal darkening agent on T2-weighted MR images with uptake into the reticuloendothelial cell system, was administered intravenously by bolus injection of 8 to 12 micromol Fe/kg body weight. Patients were scanned with breath-hold coronal and axial two-dimensional (2D) time of flight (TOF) MRA (TR = 31.0 msec, TE = 9.8 msec, flip angle (FA) = 50 degrees, and 6.9-second acquisition time per section) sequences. Signal intensity values of liver parenchyma, the portal venous system, and background were obtained for quantitative analysis. The clinical relevance of additional plain and contrast-enhanced MRA studies for surgical planning was assessed by independent reading of three readers. Liver signal-to-noise ratio (SNR) significantly decreased following iv injection of Resovist; however, SNR values of the portal veins or hepatic veins did not change significantly. Visibility of the portal venous system improved significantly (tertiary branches visible: pre in 15.2% versus post in 87.0% of patients). Resovist-enhanced 2D-TOF MRA may improve planning of liver resections by better demonstrating the relationship of central liver lesions and vessels on source images. The decrease in liver SNR at a constant vessel SNR after iv injection of Resovist improves MRA of the liver. SPIO-enhanced 2D-TOF MRA scans are superior to plain 2D-TOF MRA studies and may be added for the workup of preoperative patients.

The equivalence in average bioavailability between formulations may not be sufficient for assessment of bioequivalence. The difference in intrasubject variability between formulations should also be considered. This article presents an unbiased test procedure for equivalence in intrasubject variability of bioavailability that is uniformly more powerful than the two one-sided tests procedure proposed by Liu and Chow. Under a stronger condition, a uniformly most powerful invariant test for this problem is proposed. Some numerical comparisons and an example are also presented.

Visual field changes are one of the main parameters used to monitor progression of glaucoma. This study assesses the degree of intra-observer and inter-observer agreement among nine observers in grading visual fields in glaucoma patients using a visual field system previously described by Jay. The results show a median inter-observer agreement of 61% (median kappa = 0.52) and a median intra-observer agreement of 72% (median kappa = 0.65). This system for grading fields in glaucoma has a high degree of intra-observer agreement, suggesting it is a useful system for longitudinal follow-up of patients by a single observer. The higher degree of disagreement between observers points to the need for careful pretraining of observers in clinical management and research where the results from visual field examinations are to be graded by more than one clinician.

A rapid extraction, clean-up, and RPLC procedure suitable for routine quantitative analyses of alkamide levels in Echinacea purpurea extracts is described. The 13 C-NMR spectra of the main diene-diyne alkamides in E. purpurea are reported. Alkamide levels differed significantly among roots, rhizomes, stems, leaves, and flowers of E. purpurea. Roots were distinguished from other plant parts by higher levels of the C 12 diene-diyne alkamides, whereas levels of the C 12 tetraene alkamides and C 11 diene-diynes were highest in vegetative stems. The ratio of the two stereoisomeric C 12 tetraene alkamides differed between flowers and all other E. purpurea parts. These results are important for standardisation of medicinal preparations of E. purpurea.

The variation of barley kernels was studied among and within small breeders' plots and within individual barley plants. Differences between the basal, middle, and apical regions of the ear, and differences among individual kernels from different positions in the ear were examined. Kernel weight and protein content varied widely in single kernels of Alexis barleys grown in small plots in different European countries. Sieving tests of three regional fractions of the ear indicated that the kernels of apical fractions were smaller than those of the other two regions. This was also clearly demonstrated by weights of single kernels. The average protein contents of the three regional fractions of the ear did not differ significantly in most cases. However, the variation within one ear and between main and secondary stems of the same plants was of the same magnitude as that among different plants. The β-glucan contents did not vary significantly between the three regional fractions, among individual kernels, or between main and secondary stems. Germination behavior determined by traditional methods did not vary significantly within the ear. However, the Germination Index of the apical fractions was, in some cases, slightly higher than that of the other fractions of the ear.

Zusammenfassung Ziel: Ziel unserer prospektiven Studie war die optimierte Bestimmung des hypophysären Somatostatin-Rezeptorstatus in der 111 -In-Pentetreotid-Szintigraphie und der intraindividuelle Vergleich mit dem pharmakologischen Effekt von Octreotid bei florider Akromegalie. Methoden: Bei n = 22 Patienten mit Wachstumshormon-(GH)-sezernierendem Hypophysenadenom wurde eine 111-In-Pentetreotid-Szintigraphie durchgeführt und die spezifische Nuklidakkumulation in der Hypophysenregion (Auswertung sowohl visuell als auch semiquantitativ mittels ROI-Technik und Berechnung verschiedener Uptake-Indizes) mit dem akuten GH-Abfall nach 100 ug Octreotid s.c. (Octreotid-Akuttest) korreliert. Ergebnisse: Der von uns vorgeschlagene Uptake-Index (Quotient zirkuläre Hypophysen-ROI : irreguläre Zerebrum-ROl, jeweils cts/pixel nach Untergrund-Korrektur im sagittalen SPECT-Schnitt mit der maximalen Hypophysendarstellung 24 h p. i.) korreliert am besten mit dem pharmakologischen Effekt (akuter GH-Abfall) von Octreotid; seine obere Normgrenze liegt im Bereich von 3,5. Schlußfolgerungen: Da sich häufig auch die normale Hypophyse szintigraphisch darstellen läßt, ist die rein visuelle Abgrenzung zum pathologischen Rezeptorstatus manchmal uneindeutig. Ein mittels standardisierter ROI-Technik berechneter, hypophysärer Uptake-Index erleichert diese Abgrenzung und hilft so, mögliche Responder für eine Octreotid-Langzeittherapie zu selektieren.

In a blinded, randomized design, six histopathologists with an interest in gynecological pathology examined the inter- and intraobserver variation of the histopathological diagnosis of endometrial hyperplasia according to the World Health Organization (WHO) classification of 1975 and the new WHO classification of 1994. On four occasions, the pathologists assessed hematoxylin/eosin-stained slides from 128 cases originally diagnosed and coded in the Snomed system as endometrial hyperplasia. In the first and third rounds, the slides were classified according to the 1975 classification and in the second and fourth rounds according to the 1994 classification. The overall interobserver agreement in the two rounds where the 1975 classification was used was 0.47 and 0.51, and the kappa values 0.24 [95% confidence interval (CI) 0.21-0.27] and 0.30 (95% CI 0.27-0.33). The overall interobserver agreement in the two rounds using the 1994 classification was 0.45 and 0.41 and the kappa values 0.25 (95% CI 0.23-0.28) and 0.20 (95% CI 0.17-0.22). Reducing the classification to two categories with clinical significance (atypical endometrial hyperplasia versus others in the 1975 classification, and atypical endometrial hyperplasia, complex versus others in the 1994 classification) increased the overall agreement of the 1975 classification in both rounds to 0.91 and of the 1994 classification to 0.92 and 0.90. The kappa values increased to 0.54 (95% CI 0.49-0.58) and 0.49 (95% CI 0.45-0.54) in the 1975 classification and to 0.59 (95% CI 0.54-0.63) and 0.42 (95% CI 0.37-0.46) in the 1994 classification. The intraobserver overall agreement for the 1975 classification ranged from 0.80 to 0.55 and the kappa values from 0.70 (95% CI 0.58-0.81) to 0.28 (95% CI 0.17-0.39). The intraobserver overall agreement for the 1994 classification ranged from 0.71 to 0.46 and the kappa values from 0.60 (95% CI 0.51-0.70) to 0.20 (95% CI 0.09-0.30). It is concluded that there is considerable inter- and intraobserver variation using both the 1975 and the 1994 classifications of endometrial hyperplasia. We propose that there is need for a specification and for a simplification of the classification.

Reproducibility of operator processing for radiation dose and biological half-life was assessed for radioimmunotherapy. Mean coefficient of variation for intra-operator consecutive processing and for inter-operator processing was less than 15% for all tissues. The mean coefficient of variation for intraoperator processing over 2 wk or inter-operator processing comparing an experienced and less experienced operator was generally greater, and particularly so for tumors. Satisfactory reproducibility was achievable using visual determination of regions of interests after 80 h of training.

Purpose To evaluate and compare the 1-year postoperative levels of posterior capsule opacification (PCO) as well as the level of anterior capsule retraction and opacification (ACO) after implantation of two single-piece hydrophobic acrylic intraocular lens (IOL) models. Methods Randomised, controlled, prospective and double-blind study including 148 eyes of 74 patients (age range, 61–80 years) with bilateral senile cataract. Each patient underwent surgery with implantation of an AcrySof SA60AT (Group A) in one eye and Tecnis ZCB00 (Group B) in the fellow eye by the same experienced surgeon. Lens allocation to the first or second operated eye followed a randomisation process. At 12 months postoperatively, the PCO level was evaluated with the Evaluation of Posterior Capsule Opacification software, whereas the level of ACO and capsule retraction was evaluated and graded subjectively. Results All surgeries were uneventful. The mean PCO scores were 0.10±0.17 and 0.21±0.89 in Groups A and B, respectively, with no statistically significant differences between the groups (p=0.47). No significant correlation was found between the PCO scores in Groups A and B (r=0.16, p=0.17). Regarding ACO, it was present in 15 eyes (20.3%) and two eyes (2.7%) in Groups A and B, respectively (p=0.37). Capsular phimosis (13 eyes, 17.6%) was only observed in Group A. Conclusions Both IOLs had a similar low rate of PCO 1 year after surgery. However, there seems to be a difference in the anterior capsule behaviour between both IOL models.

The objectives of the study were to evaluate the image quality and diagnostic performance of sinogram-affirmed iterative reconstruction (SAFIRE) for detecting hepatic metastasis and to estimate the potential radiation dose reduction at abdominal computed tomography (CT).Fifty-nine consecutive patients (mean age, 59.2 years; range, 42-81 years) who had hepatic metastasis and who underwent dual-source abdominal CT were enrolled in this study. The image noise of the liver was compared between full-dose filtered back projection images (FD-FBP) and simulated half-dose images, which used only single-source projection data, and reconstructed with different strengths of SAFIRE (HD-SAFIRE(1-5)) by 1-way analysis of variance with Bonferroni correction. The diagnostic performance for hepatic metastasis was compared by logistic regression with the weighted least squares method and noninferiority test between the FD-FBP images and the half-dose sinogram-affirmed iterative reconstruction (HD-SAFIRE) images.As the SAFIRE strength increased, image noise decreased (P0.001). The images of HD-SAFIRE(2) showed similar image noise for liver parenchyma (13.4 Hounsfield unit [HU]), signal-to-noise ratio for liver parenchyma (9.2), and lesion-to-liver contrast-to-noise ratio (4.5), compared with the FD-FBP images (12.6 HU, P = 0.668; 9.6, P0.999; and 4.5, P0.999, respectively). The diagnostic accuracy for hepatic metastasis with the HD-SAFIRE(2) images (87.5%) was not different from that of the FD-FBP images (87.5%, P0.999). The diagnostic performance of the HD-SAFIRE(2) images was also noninferior to that of the FD-FBP images (95% confidence interval lower limit difference [-9.16%] excluding the -10% clinical noninferiority limit). The mean (SD) volume CT dose index of FD-FBP was 11.26 (2.66) mGy, and the mean (SD) radiation dose equivalent associated with HD-SAFIRE was estimated to be 5.63 (1.33) mGy.By applying SAFIRE2, the radiation dose could be reduced by up to 50% compared with the standard-of-care abdominal CT protocol without increasing image noise and without deteriorating diagnostic performance for the detection of hepatic metastasis.

Ziel: Anhand von experimentell induzierten Leberabszessen bei Kaninchen sollte das Signalverhalten eines neuen Blutpoolkontrastmittels (24-Gadolinium-DTPA-Kaskaden-Polymer) mit dem Signalverhalten von Gadolinium-DTPA sowohl intra- als auch interindividuell verglichen werden. Material und Methode: Die Untersuchungen an 20 Kaninchen wurden mit einer FLASH-2-D-Sequenz bei 1,5 Tesla mit einer Kopfspule durchgefuhrt. Die Messungen erfolgten vor und zu verschiedenen Zeitpunkten bis 60 Minuten nach Gabe der beiden Kontrastmittel. Ergebnisse: Der interindividuelle Vergleich ergab signifikante Unterschiede (T-Test, p < 0,05) der relativen Signalintensitaten fur das Abszeszentrum (jeder Meszeitpunkt nach Kontrastmittel (KM)-Gabe), fur den Abszeswall (jeder Meszeitpunkt zwischen 15 und 60 Minuten nach KM-Gabe) und fur die Pfortader (jeder Meszeitpunkt zwischen 30 Sekunden und 7,5 Minuten nach KM-Gabe). Nach Gabe von Gadolinium-Polymer resultierte ein hoherer Abszeszentrum-zu-Leber-Kontrast (jeder Meszeitpunkt zwischen 30 Sekunden und 12,5 Minuten nach KM-Gabe) und ein hoherer Abszeszentrum-zu-Abszeswall-Kontrast (jeder Meszeitpunkt zwischen zwei und 7,5 Minuten nach KM-Gabe) im Vergleich mit den Messungen nach Gadolinium-DTPA. Schlusfolgerung: Der hohere Kontrast zwischen Lebergewebe und Abszeszentrum, nach Gabe von Gadolinium-Polymer, ermoglichte eine langer andauernde und insgesamt verbesserte Abgrenzbarkeit der Leberabszesse in diesem Tiermodell. Purpose: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. Methods: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 μmol/kg dose of gadolinium polymer and of 100 μmol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. Results: The interindividual comparison (unpaired T-test, p < 0,05) yielded significant differences of the relativ signal intensities of the abscess centre (at any time point after contrast-media application), abscess wall (between 15 and 60 minutes after contrast media application), and portal vein (between 30 seconds and 7.5 minutes after contrast media application). The interindividual comparison showed a significantly higher abscess centre - liver contrast (between 30 seconds and 12.5 minutes after contrast media application) and a significantly higher abscess wall - centre contrast (between two and 7,5 minutes after contrast media application) after the application of gadolinium polymer compared with gadopentetate dimeglumine. Conclusion: In this animal model, the higher abscess centre - liver contrast after the application of gadolinium polymer was the basis for a better and prolonged visibility of the abscesses, as compared with images acquired after injection of gadopentetate dimeglumine.

Purpose: Because some patients show a surprising variation in serial serum prostate specific antigen (PSA) values, we determined the intra-individual or physiological variation in serum PSA by collecting sera 2 to 3 weeks apart without any prostatic manipulation.Materials and Methods: Because 4.0 to 10.0 ng./ml. PSA is the critical range for decision making, we asked all men with a PSA in this range to return 2 to 3 weeks later for a second measurement. Total serum PSA was determined by the Hybritech Tandem-R, [dagger] automated Tosoh AIA-600 [double dagger] and Delfia [Section] immunoassays. Free and complexed serum PSA was determined by the Delfia assays. Between assay variation (first blood specimen retested on a separate day with the second blood specimen) was compared to the physiological variation (first versus second blood specimens).[dagger] Hybritech, Inc., San Diego, California[double dagger] Tosoh Medics, Foster City California[Section] Delfia, Turku, FinlandResults: Mean coefficient of...

RATIONALE AND OBJECTIVES: To introduce routine bilaterally antegrade selective stationary digital subtraction angiography (DSA), and prospectively compare it with unselective stationary DSA in the detection of calf arteries and assess additional time and complication rate. METHODS: Twenty-five patients received one unselective and two separate antegrade selective studies of each calf. Images were evaluated for image quality, number of depicted run-off vessels, and potential crural bypass recipient arteries. RESULTS: Bilaterally antegrade selective DSA was significantly superior in image quality and motion artifacts (P < 0.01). The number of adequately depicted run-off arteries per calf increased from 79% (2.37 of 3) to 96% (2.89 of 3) for legs with advanced peripheral vascular disease (PVD). Seventy-nine instead of 62 potential bypass recipients were identified (P = 0.002). Mean procedure time needed for selective catheterizations was 7 minutes. No adverse events were seen. CONCLUSIONS: Bilaterally antegrade selective DSA clearly is superior to aortic run-off DSA depicting tibial arteries. It requires comparatively small additional effort. Outflow vessel detection essentially is independent of advanced PVD.

The effects of psychological parameters on resting metabolic rate (RMR) have been inadequately researched. The purpose of this study was to investigate relationships between anxiety and RMR. Seventy-nine male college students completed the trait portion (form Y-2) of the State-Trait Anxiety Inventory (C. D. Spielberger, R. L. Gorsuch, R. Lushene, P. R. Vagg, and G. A. Jacobs. Self-evaluation questionnaire (form Y). In: Manual for the State-Trait Anxiety Inventory. Palo Alto, CA, Consulting Psychologists Press, 1983) as a screening. Volunteers whose trait anxiety scores were = or = 1 SD above (52.7 +/- 2.7, n = 9) or below (26.5 +/- 3.0, n = 11) the male college student normal values (38 +/- 9) participated in the study. Fat-free weight was assessed using a seven-site skinfold equation (A. S. Jackson and M. L. Pollock. Phys. Sports Med. 13: 76-90, 1985). Resting metabolism was measured (Sensormedics metabolic cart model 2900) at two separate trials (1-2 wk apart) in the early morning after a 12-h fast and 36 h postexercise. An analysis of covariance with fat-free weight as the covariate revealed a significantly greater (P < 0.005) RMR in the high trait anxious group than in the low trait anxious group. State anxiety (form Y-1) assessments made before and after each RMR measurement revealed a significant main effect of group such that state anxiety was higher in the high trait anxious than in the low trait anxious group for both trials before and after RMR measurement. Moreover, a significant (P < 0.003) main effect for the time factor was found showing that state anxiety was reduced after the RMR procedure. The results of this study show that a statistically significant portion of the variance in RMR can be accounted for by individual differences in anxiety.

La densite intracerne du bois de chene etant consideree comme un critere important de sa qualite, nous avons etudie la variabilite des composantes microdensitometriques du cerne (densite du bois initial, largeur du bois initial, densite du bois final, largeur du bois final). Dans une premiere partie, nous nous sommes interesses a la variabilite intra-arbre de la densite, avec l'âge cambial, la largeur de cerne et le niveau dans l'arbre. Nous avons utilise des methodes de regression pour etablir des modeles de variations des differentes variables considerees et nous avons etudie les parametres de ces modeles par analyse de variance. Nous avons montre que dans l'arbre la largeur du bois initial pouvait etre consideree constante et que la densite du bois initial et du bois final ne dependaient que de l'âge. A largeur de cerne et âge fixes, l'effet du niveau dans l'arbre est significatif. Les parametres observes au niveau le plus bas de notre echantillonnage sont statistiquement differents de ceux des hauteurs superieures. Dans une seconde partie, nous avons etudie la variabilite interindividuelle de la densite du bois ; nous avons travaille sur vingt-quatre arbres provenant du nord-est de la France. Nous avons en particulier etudie l'effet du site et de l'arbre dans le site sur les parametres des modeles mentionnes ci-dessus. Nous avons trouve des effets «arbre dans site» et «site» sur certains des parametres, mais ces resultats sont a considerer avec prudence compte tenu de la relative faiblesse de notre echantillonnage. Nous pouvons cependant confirmer l'importance de la variabilite interindividuelle sur la densite du bois.

Quantitated lung function parameters are usually interpreted in relation to so-called "normal ranges' obtained from healthy study groups. The aim of this paper is the critical review of formulas and the evaluation of intraindividual variation in modern lung function testing. To which extent is the total variation of lung function parameters in cross-sectional studies (usually serving as basis for the normal range) attributed to the intraindividual variation between repeated measurements? This question raises a further question: are lung function values in the normal range really normal? To assess spirometric and body plethysmographic parameters 26 healthy subjects from three medical centers underwent 30-72 measurements over a period of 2 months for the determination of variations due to (1) intraindividual variation over time and (2) interindividual variation. For each subject, predicted values of different lung function parameters published by Quanjer et al. [Eur Respir J 1993; 6:5-40.1], of intrathoracic gas volume by Ulmer et al. [Die Lungenfunktion; Stuttgart, Thieme, 1991] and of total airway resistance by Ruehle and Matthys [Pneumologie 1976;153:223] were applied. When converted into percent predicted and adjusted for differences in medical centers, the intraindividual standard deviation was estimated to be about half of the interindividual standard deviation. We conclude that the normal range of lung function parameters derived from the standard deviation within populations is too wide for the assessment of individual values. Interpretation of individual lung function measurements should primarily be based on the "individual normal range' derived from former lung function measurements of the individual and only secondly on the "predicted value'.

In the pharmacotherapy of chronic generalized anxiety disorder (GAD) rationally grounded guidelines on the treatment to choose in individual cases are not evident in the literature. The present study was designed to address this question in 30 patients with chronic GAD. Within a period of 31 weeks amitriptyline 30 mg/day, flupentixole 1.5 mg/day, clotiazepam 15 mg/day and placebo were administered 4 times for 1 week, double-blind and at random to each patient. U tests showed that in 19 patients one agent was superior to the other substances (p0.05). There was no significant difference between the drugs in 11 patients. However, a meta-analysis across all single-subject experiments showed that in individual patients suffering from chronic GAD differential effects of anxiolytic agents can be found by means of single-subject experiments (p0.001). The findings lend further support to the hypothesis that, in an approach to optimize pharmacological treatment of patients suffering from chronic GAD, single-subject experiments may be useful.

Background and Design: Benzoic acid (BA) was used to induce nonimmunologic contact irritation in 10 younger (23-47 years old) and 5 older (72-90 years old) healthy volunteers. BA2.5% in petrolatum was applied to 8 locations on the face, neck and volar forearm. Changes in the skin blood flow were monitored using a laser Doppler flowmeter. Also measured at each location were baseline measurements of skin blood flow, transepidermal water loss, stratum corneum hydration, skin surface temperature and skin surface pH. Results: The neck area exhibited the greatest reaction in both age groups while the forearm exhibited the least. At each site tested, the younger group consistently demonstrated greater reactivity to BA. A significant correlation was noted between stratum corneum hydration and irritation. Conclusion: This information provides a basis to further study the frequent poorly understood intolerance of the face to topical formulation.

Five microflora associated characteristics (MACs) were studied in faecal samples from two groups of inbred rats, either obtained from three consecutive days or up to 13 times during a one month period. The results show minor inter- and intra-individual variations. Baselines for each MAC have to be established with regard both to species and diet, before studying host-microbiota related co-functions. Keywords: rats, microbiota, biochemical functions, germfree life.

To evaluate and compare B1 homogeneity for breast magnetic resonance (MR) imaging performed at 3 T with dual-source radiofrequency (RF) transmission to 1.5-T MR imaging and 3-T MR imaging with quadrature transmission.This prospective study received institutional review board approval and patients provided informed consent. Women (n = 25; mean age, 53 years; range, 30-68 years) suspected of having breast lesions underwent breast MR imaging examinations on comparable 1.5-T and 3-T clinical systems between February and May 2012. B1 maps were obtained at 1.5 T and at 3 T with quadrature and dual-source RF transmission. Intrabreast differences and differences in mean B1 values between right and left breasts were investigated by using two-sided multivariate analysis of variance with interaction; t tests were used to compare the differences between measured whole-breast mean B1 values and requested B1 values.With quadrature transmission at 1.5 T and 3 T, the mean B1 values showed a statistically significant difference: left-breast measured B1 was -8.9% of requested B1 value at 1.5 T and -13.7% at 3 T (P.001), whereas right-breast measured B1 was +5.4% of requested B1 value at 1.5 T (P.001) and +2.7% at 3 T (P = .01). With dual-source RF transmission at 3 T, mean B1 values across the breasts were not statistically different, nor were the measured B1 values compared with requested B1 values (left breast, -0.6%; right breast, -0.7%). At 3 T with dual-source transmission, slight intrabreast local variations in B1 were recorded.MR imaging at 3 T with dual-source RF transmission offered an overall B1 homogeneity for breast imaging that was better than that obtained at 1.5 T and with quadrature transmission.