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Biomedical subjects

W Duquet

Publications and source records attributed to W Duquet.

16 recordsLinked to original sources
PubMed2005

A defined donor activating natural killer cell receptor genotype protects against leukemic relapse after related HLA-identical hematopoietic stem cell transplantation.

Killer cell immunoglobulin-like receptors (KIRs) recognize different groups of Human Leukocyte Antigen (HLA) class I alleles and are expressed by natural killer (NK) cells and some T lymphocytes. NK cell cytotoxicity is triggered by failure to recognize the appropriate HLA class I ligand on target cells. Recently, it has been shown that HLA class I ligand incompatibility in the graft-versus-host (GvH) direction is associated with a better outcome in haploidentical hematopoietic stem cell transplantation (HSCT). Since KIR genotypes are very diverse in the population, we explored whether or not the donor KIR genotype could affect the graft-versus-leukemia (GvL) effect in the related HLA-identical HSCT setting. We determined the KIR and HLA genotypes of 65 HLA-identical patient-donor siblings. We found that the presence of two activating KIRs, 2DS1 and 2DS2, in the donor was significantly associated with a decreased leukemic relapse rate (P=0.03; OR=0.18; 95% CI: 0.037-0.88). Moreover, the probability of relapse at 5 years was significantly lower for patients who received a graft from a donor with the 2DS1(+)2DS2(+) genotype than for those who received a transplant from other donors (17 vs 63%, respectively; P=0.018). In conclusion, this study suggests that a joint effect of these two selected activating KIRs in the donor might confer some protection against leukemic relapse.

Adolescent↗
PubMed2004

Disability evaluation in chronic fatigue syndrome: associations between exercise capacity and activity limitations/participation restrictions.

OBJECTIVE: In an attempt to examine whether impairments in cardiorespiratory fitness are associated with daily functioning in patients with chronic fatigue syndrome (CFS), this study addresses the correlations between exercise capacity and activity limitations/participation restrictions. DESIGN: Prospective observational study. SETTING: An outpatient tertiary care, chronic fatigue clinic at the Vrije Universiteit Brussel (VUB), Belgium. SUBJECTS: Seventy-seven patients fulfilling the 1994 Centers for Disease Control and Prevention (CDC) case definition for CFS. INTERVENTIONS: All patients filled in the Chronic Fatigue Syndrome Activities and Participation Questionnaire (CFS-APQ) and performed a maximal exercise stress test on a bicycle ergometer. Heart rate was monitored continuously by use of an electrocardiograph. Metabolic and ventilatory parameters were measured through spirometry. RESULTS: A statistically significant correlation between the score obtained with the CFS-APQ and the body weight-adjusted peak oxygen uptake (Spearman rho = -0.32; p = 0.005), functional aerobic impairment (rho = 0.33; p = 0.004), workload/body weight (rho = -0.30; p = 0.009), exercise duration (rho = -0.30; p = 0.008), and the percentage of target heart rate achieved (rho = -0.33; p = 0.004) was observed. The correlations between the remaining exercise capacity parameters and the scores obtained with the CFS-APQ all indicated a trend towards association (0.01 <p<0.05). CONCLUSIONS: These results suggest a moderate association between exercise capacity and activity limitations/participation restrictions in patients with CFS. The observed correlations lack strength to predict activity limitations/ participation restriction based on exercise capacity parameters. Disability evaluation in CFS should therefore encompass both exercise capacity testing and measurements at the activity/participation dimension.

Adult↗
PubMed2004

Lymphedema development following breast cancer surgery with full axillary resection.

Several studies have investigated the influence of disease related, treatment related, and patient related risk factors on the development of postmastectomy edema (PME). The aim of the present study was to determine which factors present a higher risk of developing PME after breast surgery with full axillary resection (level I, II and III). To accomplish this aim, we investigated 245 women who underwent unilateral breast cancer surgery in the Academic Hospital of the Vrije Universiteit, Brussels. Information concerning treatment and disease related factors were collected from the patient's medical records and factors related to clinical condition were obtained by a personal interview. Arm circumference was taken at 15 cm proximal and 10 cm distal to the olecranon. PME was defined as 2.5 cm difference between the arms. Height and weight of the patient were also measured. Statistical analysis was performed by calculating the Odds Ratio and the 95% Confidence Interval. We found the following factors posed an increased risk of developing PME: axillary/supraclavicular radiotherapy, pathological status of the lymph nodes, overweight (BMI > 25 kg/m2), trauma to the arm, menopause and surgery on the dominant side.

Adult↗
PubMed2002

Anthropometric fractionation of body mass: Matiegka revisited.

In a group of 699 Belgian nursing professionals, we estimated body composition using the four-component anthropometric model, relying on the equations originally formulated by Matiegka in 1921 and later revised by Drinkwater and colleagues. We estimated muscle mass using the more recent formula proposed by Martin and co-workers. A discrepancy was noted between estimated total body mass and 'assessed' mass, suggesting erroneous estimations of the components.

Adult↗
PubMed2001

Control of acceleration during sudden ankle supination in people with unstable ankles.

STUDY DESIGN: Comparative study of differences in functional control during ankle supination in the standing position in matched stable and unstable ankles (ex post facto design). OBJECTIVES: To document acceleration and deceleration during ankle supination in the standing position and to determine differences in control of supination perturbation between stable and unstable ankles. BACKGROUND: Repetitive ankle sprain can be explained by mechanical instability only in a minority of cases. Exercise therapy for ankle instability is based on clinical experience. Joint stability has not yet been measured in dynamic situations that are similar to the situations leading to a traumatic sprain. The process of motor control during accelerating ankle supination has not been adequately addressed in the literature. METHODS AND MEASURES: Patients with complaints of ankle instability (16 unstable ankles) and nonimpaired controls (18 stable ankles) were examined (N = 17 subjects, 10 women and 7 men). The average age was 23.7 +/- 5.0 years (range, 20-41 y). Control of supination speed was studied during 50 degrees of ankle supination in the standing position using accelerometry (total supination time and deceleration times) and electromyography (latency time). Timing of motor response was estimated by measuring electromechanical delay. RESULTS: The presence of an early, sudden, and presumably passive slowdown of ankle supination in the standing position was observed. Peroneal muscle motor response was detected before the end of the supination. Unstable ankles showed significantly shorter total supination time (109.3 ms versus 124.1 ms) and significantly longer latency time (58.9 ms versus 47.7 ms). CONCLUSIONS: Functional control in unstable ankles is less efficient in decelerating the ankle during the supination test procedures used in our study. Our conclusions are based on significantly faster total supination and significantly slower electromyogram response in unstable ankles. The results support the hypothesis that both decelerating the total supination movement during balance disturbance and enhancing the speed of evertor activation through exercise can be specific therapy goals.

Acceleration↗
PubMed2001

Reproducibility and reliability of measurements using a linear isokinetic dynamometer, Aristokin.

BACKGROUND: This study was performed to investigate the intra-observer reproducibility and reliability of measurements using a linear isokinetic dynamometer (Aristokin). METHODS: Sixteen female volunteers (age 18 to 23 years) participated in 4 test sessions, each consisting of 6 warming-up movements followed by 6 repetitions of 4 different movements. During each session, the subjects consecutively performed lifting movements by flexing elbows and shoulders (at 65 cm per sec), total lifting movements with arms and legs (at 65 cm per sec), and extension movements of the legs in sitting position (at 40 and 60 cm per sec). The first 3 test sessions were performed at a weekly interval, the 4th was executed 4 weeks after the 3rd session. Force, power and explosivity (force developed per sec) were recorded. RESULTS: The intra-observer reproducibility was investigated of the 6 repetitions of the movements during each test session. The highest reproducibility for mean peak power and force was found in the combination of the 3rd, 4th, 5th and 6th measurement (intraclass correlation coefficient 0.85 to 0.99). Using this combination, the intra-observer reliability was investigated, defined as the consistency of results obtained during the 4 test sessions, performed at a weekly or longer interval. Comparison between these sessions showed that the results for mean force in the arm movement differed significantly (p=0.01) although a high between sessions correlation was found (0.96). Results for mean force and power for the 3 other movements were reliable, and no significant learning effect was observed. Lower reliability and reproducibility were observed for other parameters including explosivity and power and force at the first 0.25 sec of the test movement. CONCLUSIONS: Even after standard warming-up movements, the first 2 out of 6 measurement repetitions during a test session are not reproducible and should not be used in calculations of the results. For the combination of the 3rd to 6th repetitions, a high reliability was found for the measurement of mean force and power of the total lifting movement and of the sitting leg extension movements repeated in 4 sessions over a period of 6 weeks.

Adolescent↗
PubMed2000

Adding compression to mobilization in a rehabilitation program after knee surgery. A preliminary clinical observational study.

The cyclical loading of cartilage, which occurs during normal use of an articulation, stimulates biosynthetic activity of the chondrocytes. Therefore functional stimulation may contribute to joint repair. In this study the researchers added mobilization with compression to a standardized rehabilitation program in patients recovering from intra-articular reconstructive surgery of the anterior cruciate ligament. Thirty patients were treated with a standardized physical therapy program following surgery. For half of the patients, mobilization under compression was added to this rehabilitation program. The knee flexion range of motion (FROM) was measured using a goniometer. Patients who received mobilizations with compression reached a pre-set goal of 130 degrees FROM after a mean of six treatment sessions, compared to 11 sessions in the control group. This rapid progression was characterized by a significantly greater increase of FROM during the first two treatment sessions. The explanation for this observed effect may lie in fast response processes which could include rheological changes in synovial fluid, enhanced exchange between synovial fluid and cartilage matrix or increased synovial turnover rather than complex metabolic phenomena. The faster recovery of the pre-set goal (130 degrees of FROM) in the group receiving mobilizations with compression, would appear to justify future clinical trials investigating the potential benefits of adding these techniques to current rehabilitation programs.

Adult↗
PubMed2000

Will the use of different prevalence rates influence the development of a primary prevention programme for low-back problems?

To determine relations to low-back problems (LBP), different prevalence rates are used. The disadvantage of using different selection criteria is that studies are not comparable, except where they provide the same results. The present aim was to establish whether different prevalence selection criteria lead to different answers on a newly formed set of questionnaires. Since this set is new, reliability tests were performed (test-retest and calculations of Cronbach's Alpha, Cohen's Kappa and the intraclass correlation). Results of the questionnaire should form the cornerstones of a primary prevention programme. Altogether 1783 nurses in four Flemish (Belgian) hospitals were questioned. Information was gathered on work circumstances, education, general health, psychosocial factors, leisure activities, family situation and musculoskeletal problems. Four different datasets with variables related to lifetime prevalence LBP, annual prevalence LBP, point prevalence LBP and a set with all related variables were constructed. The variables demonstrating a relation with LBP differed slightly depending on the kind of prevalence used (lifetime, annual, point). A factor analysis on each set of prevalence related data failed due to the lack of homogeneity of the variables. Fear avoidance, coping aspects and musculoskeletal problems in other regions then the lower back were, in all circumstances, the most discriminating variables. Their discriminating power, however, differed depending on the kind of prevalence used. The differences were too small to influence the construction of the prevention programme. It is concluded that in developing a primary prevention programme any of the prevalence rates can be used. The combination of the three types of prevalence rates studied provides the most complete and reliable image.

Adaptation, Psychological↗
PubMed1999

Pain threshold in patients with rheumatoid arthritis and effect of manual oscillations.

Using a pressure algometer pain threshold (PT) measurements were carried out in the paraspinal area as well as at the knee and ankle joints in 30 adults with active rheumatoid arthritis (RA) and in 30 healthy adults. The group of RA patients was then randomly divided in two. In 15 RA patients a manual oscillation technique was applied at T12 and L4 for 12 minutes. The 15 other patients were resting. Immediately after the experimental procedure the PT was measured again at the same points in all patients. The RA patients showed a significantly (p < 0.05) lower PT than the healthy adults at all investigated points, which suggests that in RA certain changes arise in the peripheral and central nociceptive processing system, as mentioned in the literature. In the second measurement session for the RA patients the PT was significantly higher (p<0.05) after manual oscillations than after rest, at the paraspinal area of T6, L1 and L3. Further research into the long-term effect of repeated manual oscillation sessions is warranted.

Adult↗
PubMed1998

Objective roentgenologic measurements of the influence of ankle braces on pathologic joint mobility. A comparison of 9 braces.

The stabilizing effect of external support (taping and nine different ankle braces) was tested in a total of 220 functionally unstable ankles. A standard surface EMG controlled stress Roentgen test protocol was used, measuring talar tilt (TT) without support and with tape bandage or brace. Different levels of TT restraining by external support could be identified. Tape bandage and two braces had a highly significant influence on the talar tilt. The mean TT without support was decreased by using from 13.4 degrees to 4.9 degrees, by using one brace to 4.8 degrees and by using another brace to 5.9 degrees. These two braces are effective for protection during functional treatment. A classification into three grades of effectiveness is proposed. It is concluded that the stabilizing influence offered by bandages and braces should be measured before using the external support as a treatment device for acute ankle sprain and as a reliable protection against sprain injuries in daily living and sports.

Activities of Daily Living↗
PubMedDate not supplied

A method for detecting errors in data of growth studies.

The paper describes a new method used for data cleaning in growth and development studies. The method is essentially based on the assumption that an extreme value of a certain variable might be suspicious if other highly correlated variables show low compatibility with it and that, on the other hand, an extreme but possible value tends not to be erroneous if it is reinforced by another extreme but possible value of a highly correlated variable. Each variable was therefore included in at least two ratios with the highest correlated variables. A program was designed to detect extreme values of individual variables and extreme ratio values. This procedure with ratios was used to help to detect possible errors and discriminate them from true extreme values. Seen in the light of corrected data files against existing data files, the number of corrections was approximately 4.4%. If the real number of corrected errors is compared to the total number of subjects, this percentage reached 5.5%. If, when correcting, the real value was not detected with certainty, the erroneous value was then simply deleted. From our results, there is reason to believe that with this method few detectable errors will escape from the cleaning procedure. Conclusions for future correction procedures and for future growth studies in general, are also given in the paper.

Anthropometry↗
PubMedDate not supplied

Static and dynamic roentgenographic analysis of ankle stability in braced and nonbraced stable and functionally unstable ankles.

Patients suffering from functional ankle instability were selected based on a structured interview. Talar tilt was measured using supine ankle stress roentgenographs and standing talar tilt was measured using erect ankle stress roentgenographs. A digital roentgenocinematographic analysis of a 50 degrees ankle sprain simulation was performed to measure dynamic talar tilt and inversion distance between two video images (inversion speed). A significant decrease in pathologic supine talar tilt in unstable ankles was found in the braced compared with the nonbraced situation (talar tilt = 13.1 degrees versus 4.8 degrees with brace). The talar tilt with the brace after activity was still significantly lower than the initial value without the brace. The standing talar tilt of unstable ankles was shown to be significantly lower with the orthosis than without (standing talar tilt = 16.6 degrees versus 12.0 degrees with brace). Roentgenocinematographic evaluation of ankle sprain simulation showed that the mean dynamic talar tilt during simulated sprain decreased significantly in the braced ankles compared with the nonbraced ankles (dynamic talar tilt = 9.8 degrees versus 6.4 degrees braced). A significant decrease in the digital measurement of inversion distance (from 110.6 pixels to 92.4 pixels) was observed in the total sample of 39 ankles during the initial high-speed phase of the simulated sprain. The brace significantly slows down the inversion speed.

Analysis of Variance↗
PubMedDate not supplied

Bayesian estimation of the parameters of a nonlinear model. An application to human height.

The estimation of the parameters of a nonlinear model by means of the maximum likelihood procedure is widely used in the study of growth phenomena. The accuracy with which these parameters are calculated is a function of the number of measures taken and particularly, of their distribution across the growth period. If the growth curve is only partially known, the inaccuracy can increase considerably. However, if we have information on the distribution of the parameters of a model in the population, the empirical Bayes method should be used. In this paper, the principle of this approach for nonlinear modeling was recalled. The method was then applied on data of human height. Four nonlinear models are used and their performances are compared. The results show the importance of information on the quality of estimates of growth parameters and consequently on the prediction of adult height.

Adult↗