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Biomedical subjects

D De Clercq

Publications and source records attributed to D De Clercq.

At least 37 records · Page 2Linked to original sources
PubMed2001

Back care education in elementary school: a pilot study investigating the complementary role of the class teacher.

This study investigated the efficacy of guidelines for a motivated class teacher to enhance the application of back care principles, taught by a physical therapist, in fifth-grade elementary schoolchildren. Testing consisted of a practical test before and a practical test, knowledge test and candid camera evaluation 11 weeks after the program. Three groups were compared: an intervention group of 38 pupils, with extra guidelines for the teacher, an intervention group of 48 pupils, without extra guidelines and 34 controls. The intervention plus guidelines group, compared to the intervention group without extra teacher guidelines, obtained significantly higher posttest-pretest gain scores for five of the seven practical test items and scored significantly higher for seven of the nine items of the candid camera evaluation. Knowledge test scores did not differ significantly between the two intervention groups. Study results indicate that guidelines to a motivated class teacher improve efficacy of back care education in elementary schoolchildren.

Activities of Daily Living↗
PubMed2001

Necessary precautions in measuring correct vertical jumping height by means of force plate measurements.

The present study was designed to investigate the determination of vertical jumping height by means of force plate measurements. Four different sources of error influence this determination: the measurement of body mass, the determination of take off, the integration frequency, and the assessment of the initial conditions influencing the determination of the start of the movement. A theoretical model was utilized to simulate the vertical ground reaction forces in vertical jumping and to compare the outcome of analytical and numerical double integration of the vertical acceleration of the body centre of mass. A high integration frequency and an optimizing loop for body mass determination were found to be important and should be taken into account when determining jumping height parameters.

Acceleration↗
PubMed2001

Generalization of back education principles by elementary school children: evaluation with a practical test and a candid camera observation.

UNLABELLED: The efficacy of back education in elementary school children was shown using a practical test. Similar results in a candid camera evaluation were questioned. The purposes of this study were (i) to explore the relationship between the results of a practical test and the results of a candid camera procedure when evaluating back education principles, and (ii) to investigate whether in a candid camera procedure scores are still better in pupils who followed a back education programme than in controls. A candid camera evaluation followed by a practical test was performed in 71 pupils who had participated in a back education programme and 60 controls. Correlations between the two evaluation methods were significant but weak for 5 of the 9 test items in the intervention group (Rs 0.26-0.46) and for 7 test items in the control group (Rs 0.38-0.58). The difference in sum scores between the evaluation methods was significantly higher in the intervention group than in the control group (p < 0.001). The intervention group scored higher than the control group for 8 practical test items and 7 candid evaluation items. CONCLUSION: The study results question the use of a practical test for the individual evaluation of back education principles but show the usefulness of a practical test to study programme efficacy. As some principles seem to have become a habit, while for the implementation of others the pupils need external stimuli, the effects of more specific guidelines for parents and teachers to generalize back education principles require further study.

Back Pain↗
PubMed2001

Studies on the biology of schistosomiasis with emphasis on the Senegal river basin.

The construction of the Diama dam on the Senegal river, the Manantali dam on the Bafing river, Mali and the ensuing ecological changes have led to a massive outbreak of Schistosoma mansoni in Northern Senegal, associated with high intensity of infections, due to intense transmission, and the creation of new foci of S. haematobium. Data on the vectorial capacity of Biomphalaria pfeifferi from Ndombo, near Richard Toll, Senegal are presented with sympatric and allopatric (Cameroon) S. mansoni. Comparisons are made on infectivity, cercarial production, chronobiology of cercarial emergence and longevity of infected snails. Recent data on the intermediate host specificity of different isolates of S. haematobium from the Lower and Middle Valley of the Senegal river basin (SRB) demonstrate the existence of at least two strains of S. haematobium. The role of Bulinus truncatus in the transmission of S. haematobium in the Lower and Middle Valleys of the SRB is reviewed. Both S. haematobium and S. mansoni are transmitted in the same foci in some areas of the SRB.

Animals↗
PubMed2000

Biomechanical analysis of the stance phase during barefoot and shod running.

This study investigated spatio-temporal variables, ground reaction forces and sagittal and frontal plane kinematics during the stance phase of nine trained subjects running barefoot and shod at three different velocities (3.5, 4.5, 5.5 m s(-1)). Differences between conditions were detected with the general linear method (factorial model). Barefoot running is characterized by a significantly larger external loading rate than the shod condition. The flatter foot placement at touchdown is prepared in free flight, implying an actively induced adaptation strategy. In the barefoot condition, plantar pressure measurements reveal a flatter foot placement to correlate with lower peak heel pressures. Therefore, it is assumed that runners adopt this different touchdown geometry in barefoot running in an attempt to limit the local pressure underneath the heel. A significantly higher leg stiffness during the stance phase was found for the barefoot condition. The sagittal kinematic adaptations between conditions were found in the same way for all subjects and at the three running velocities. However, large individual variations were observed between the runners for the rearfoot kinematics.

Adolescent↗
PubMed2000

The epidemiology of human hookworm infections in the southern region of Mali.

Two surveys of hookworm (Necator americanus) infections, conducted three years apart (December 1994 and January 1998) in a village in the Sikasso region of Mali, revealed that overall prevalence of infection was 68.7% and 53%, respectively. In both years there was a highly significant difference between the sexes in the prevalence and abundance of infection, with male subjects carrying heavier infections than females. Both prevalence and abundance of infection increased with age, although in 1998 there was a strong interaction between sex and age, arising from the declining egg counts among 16-20-year-old females and the continuing increase among males, reinforced by the subsequent reduction among the older males (> or = 61 years) and concomitant increase among females. After controlling for the effects of age, sex and their interaction, a highly significant positive relationship was detected between faecal egg counts of individuals who were examined in both 1994 and 1998 (n = 134), indicating predisposition to infection. This relationship remained significant in each of 4 age classes spanning 7-79 years. The members of some family compounds were shown to carry heavier infections than expected whilst others were less infected, suggesting compound-related clustering of hookworm infections. The use of footwear increased with age but there was no significant relationship between the extent of use of footwear and the abundance of hookworm infection. Eyesight deteriorated with age and impaired vision was particularly prominent among the older sectors of the community, a legacy from the time when onchocerciasis was widely prevalent in the region. Although men with partially damaged eyes carried lower infections than expected for their age, no overall significant relationship was found between quality of vision and hookworm infections. These results are discussed in relation to hookworm epidemiology in general and in Mali in particular.

Adolescent↗
PubMed2000

What is the effect of combining artesunate and praziquantel in the treatment of Schistosoma mansoni infections?

A group of 110 individuals with Schistosoma mansoni infection was investigated. Patients were allocated to one of three treatment groups and given artesunate or praziquantel alone or both in combination. Combined artesunate-praziquantel significantly increased the number of individuals cured at 5 weeks post-treatment, but at 12 weeks was only better than artesunate alone and at 24 weeks there was no statistically significant difference between the three groups. Egg count reduction rate was similar to the rate obtained with praziquantel used alone.

Adolescent↗
PubMed2000

Effects of back care education in elementary schoolchildren.

UNLABELLED: The purpose of this study was to investigate the effects of a back care education programme, consisting of six sessions of 1 h each, in fourth- and fifth-grade elementary schoolchildren. Testing consisted of a practical performance and a back care knowledge test. Forty-two subjects and 36 controls performed a pre-test and were tested within 1 wk after the programme. To monitor effects and follow-up effects on a larger sample, 82 different pupils were tested within 1 wk after the programme and 116 other children 3 mo after. Both larger samples were compared with one group of 129 controls. Interrater reliability for the test items of the practical assessment was high; intraclass correlation coefficients varied from 0.785 to 0.980. In the pre/post design study, interaction between time and condition was significant for the sum score of the practical assessment and for the knowledge test (p < 0.001), with higher scores for the intervention group (15% improvement for the knowledge test score, 31.6% for the practical sum score). Significantly higher sum scores for the knowledge test and for all practical assessment items were found in the intervention groups, tested within 1 wk and 3 mo after the programme, in comparison with the control group (p < 0.001). CONCLUSION: The effectiveness of a primary educational prevention programme on back care principles was demonstrated in this study. Effectiveness, long-term outcomes and behavioural changes need further evaluation to optimize back care prevention programmes for elementary schoolchildren.

Back Pain↗
PubMed1999

The epidemiology of a recent focus of mixed Schistosoma haematobium and Schistosoma mansoni infections around the 'Lac de Guiers' in the Senegal River Basin, Senegal.

A village with mixed Schistosoma mansoni and S. haematobium infections (probably in a early endemic phase) was identified around the Lac de Guiers in the Senegal River Basin. In documenting the epidemiology of both schistosomes, we focused on prevalence and intensity of infection, transmission patterns and the impact of treatment. S. mansoni prevalences (near 100%) and egg counts (overall geometric mean eggs per gram of faeces (epg) of 589 were high in all age groups, with 35% of individuals excreting > 1000 epg, and showing a slow decline in egg output only after the age of 30 years. The overall prevalence (28%) and egg counts (2% > 50 eggs/10 ml) of S. haematobium were low, with mean counts of 6.3 eggs/10 ml. Maximal mean S. mansoni egg counts were found in 5-9 year-old boys and in 15-19 year-old girls; S. haematobium maximal counts in 1-4 year-old boys and in girls aged 5-9. Extremely high Biomphalaria pfeifferi infection ratios were recorded over the whole year. Following a single treatment, re-infection was rapid with prevalences and mean egg counts of both Schistosoma species reaching pretreatment levels within 7 months.

Adolescent↗
PubMed1998

The influence of exercise and dehydration on postural stability.

The aim of this study was to investigate the effects of exercise-induced and thermal dehydration on postural balance. Eight male subjects cycled for 2 h at a power output equal to 57-63% VO2max on two different occasions: once without drinking (NF) and once with intake of 1.9 l of a carbohydrate-electrolyte solution (FR). Before and after the exercise test, the velocity of the centre of pressure (COP) excursion was measured on a force platform during 30-s bipedal standing in normal position, feet side by side, and tandem position, feet heel to toe. On another occasion, eight subjects underwent seven consecutive sauna sessions (85 degrees C, 50% rh) of 15 min duration with no fluid replacement (S) to induce thermal dehydration. Mean fluid loss was 2.7 (+/- 0.4)%, 0.5 (+/- 0.5)% and 3.0 (+/- 0.6)% of body mass after NF, FR and S, respectively. Mean velocity of COP excursion after the exercise test was significantly higher in the NF than in the FR trial (p < 0.05). Postural stability was not influenced by S. In conclusion, prolonged exercise without fluid ingestion seems to negatively affect postural stability, whereas no effect is observed after exercise with fluid replacement or after thermal dehydration.

Adult↗
PubMed1997

Assessment of cure by detection of circulating antigens in serum and urine, following schistosomiasis mass treatment in two villages of the Office du Niger, Mali.

Eight weeks after mass chemotherapy with 40 mg/kg praziquantel in two villages in Office du Niger (an irrigation area in Mali, endemic for both Schistosoma haematobium and Schistosoma mansoni) the circulating anodic (CAA) and cathodic (CCA) antigen detection assays were carried out on serum and urine samples. Both prior and post treatment highest prevalence was measured with the urine-CCA assay. Cure rates determined by antigen detection were almost half that of the egg counting methods. It was shown that the reduction in intensity should be preferentially assessed by the serum-CAA assay. Compared with egg detection, a single antigen detection assay gave a much better assessment of the impact of chemotherapy.

Animals↗
PubMed1997

Circulating anodic and cathodic antigen in serum and urine of mixed Schistosoma haematobium and S. mansoni infections in Office du Niger, Mali.

In Office du Niger, an area endemic for both Schistosoma haematobium and S. mansoni in Mali, circulating anodic (CAA) and cathodic (CCA) antigen detection assays were performed on pretreatment serum and urine samples from two villages, Rigandé and Siguivoucé, and compared with egg counting methods. The highest prevalence was obtained with the urine-CCA assay which also had the highest sensitivity to S. haematobium, S. mansoni or mixed infection. A single urine-CCA assay was as sensitive as repeated egg counts (one stool+two urine examinations per individual). When the different assays were tested in parallel, several combinations including assays on serum were found to be highly sensitive. As urine sampling is widely accepted, urine assays will be used for further monitoring these villages one and two years after chemotherapy.

Animals↗
PubMed1997

Failure of mebendazole in treatment of human hookworm infections in the southern region of Mali.

Preliminary studies indicated that single-dose (500 mg) mebendazole gave disappointing results in the treatment of hookworm infections (Necator americanus) in Mali. A placebo-controlled, randomized trial conducted with the participation of 103 infected subjects (background hookworm prevalence > 50%) confirmed that mebendazole (Vermox) did not reduce parasite burdens significantly, as assessed through fecal egg counts. In contrast, a group of subjects treated with pyrantel (Combantrin) experienced a significant reduction in fecal worm egg counts (overall, both sexes combined showed a 75% reduction). Male subjects carried significantly more intense infections compared with females, but there was no gender difference in response to treatment. A standard egg hatch assay showed that N. americanus from our subjects in Mali was more resistant to benzimidazoles compared with a laboratory-maintained strain that had not been exposed to anthelmintics in more than 100 generations (50% effective dose = 0.12 and 0.07 microg/ml of thiabendazole, respectively), suggesting that, among other possibilities, the development of resistance to the benzimidazoles by N. americanus may have contributed to the drug failure. Whatever the underlying explanation, our results indicate that single-dose treatment with mebendazole is an ineffective treatment for hookworm infections and despite its relatively cheap cost and wide availability, mebendazole should not be considered a drug of choice in the mass treatment of hookworm infections in this region of Mali.

Adolescent↗
PubMed1995

The mechanical properties of the human heel pad: a paradox resolved.

In vivo and in vitro mechanical testing of the human heel pad gave apparently different properties for this structure: the in vivo stiffness is about six times lower, whereas the percentage of energy dissipation is about three times higher (up to 95% loss). It was postulated that this divergence must be ascribed to the lower leg being involved in in vivo heel pad testing. This hypothesis is presently evaluated by applying the two experimental procedures formerly used in the in vivo (an instrumented pendulum) and in vitro (an Instron servo-hydraulic testing machine) investigations on the same isolated heel pad samples. Instron load-deformation cycles mimicking pendulum impacts (i.e. 'first loop-half cycles') are first evaluated and then compared to real pendulum impacts. When performed properly, the pendulum test procedure reveals the same mechanics for isolated heel pads as the Instron does. The load-deformation loops are basically identical. Thus similar non-linear stiffnesses (about 900 kN m-1 at body weight) and comparable amounts of energy dissipation (46.5-65.5%) are found with both types of test, still being largely different from the former in vivo results (150 kN m-1 and 95%, respectively). Therefore, the present findings support the hypothesis that the presence of the entire lower leg in in vivo tests indeed influences the outcome of the measurements. It must be concluded that the previously published in vivo data, if interpreted for the heel pad alone, implied not only an incorrectly low resilience but also a value far too low for stiffness.

Adult↗
PubMed1995

Schistosoma and geohelminth infections in Mali, west Africa.

We report on the prevalence of schistosomiasis and geohelminth infections in Mali, Central West Africa, based on data from the National Schistosomiasis Control Programme of Mali (1982-1991) and from our recent surveys (1992-1993). Combined national figures and regional data are presented from both surveys. Schistosomiasis showed an overall prevalence of 30.1%, with lowest prevalence in Sikasso Region and highest prevalence in Segou Region. Ascaris lumbricoïdes (0.12%) and Trichuris trichiura (0.42%) were comparatively rare, but hookworm infections were more widespread (8.0%). No hookworm infections were detected in the arid northern Region and the highest prevalence (18.7%) was encountered in the humid south of the country. There was a significant positive relationship between the prevalence of hookworm infection and total annual rainfall per region. Overall the prevalence of concurrent infections with schistosomes and hookworms was significantly less than expected, although there were regional differences which were discussed in the light of local variations in climatic and other factors likely to affect transmission.

Adolescent↗
PubMed1994

The mechanical characteristics of the human heel pad during foot strike in running: an in vivo cineradiographic study.

The compressive properties of the heel pad during the heel strike when running (barefoot and shod, two subjects, 4.5 m s-1) were studied by means of a high-speed two-dimensional cineradiographic registration (150 frames s-1) of an actual running step. Vertical ground reaction forces were measured with a force platform. In barefoot running the heel pad deforms to a maximal percentage deformation of 60.5 +/- 5.5%. In shod running the heel pad deforms only 35.5 +/- 2.5% and the nonlinear force-deformation relationship reflects an increasing stiffness when deformation rises. Although the amplitudes of the vertical ground reaction forces do not differ notably in both conditions, barefoot running implies a maximal deformation to the fatty heel tissue, reducing its functional role from shock reduction towards local protection of the heel bone. It is argued that embedding the foot in a well-fitting shoe increases the effective stiffness of the heel pad.

Adipose Tissue↗
PubMed1994

Studies on transmission and schistosome interactions in Senegal, Mali and Zambia.

The transmission and interaction of schistosomes in the Senegal River Basin in Mali and Zambia are reviewed and some preliminary field data are presented. In the Senegal River Basin four species of schistosomes are prevalent: Schistosoma mansoni, S. haematobium, S. bovis and S. curassoni as well as the following potential intermediate hosts: Biomphalaria pfeifferi, Bulinus globosus, B. umbilicatus, B. truncatus, B. senegalensis and B. forskalii. The role of each of these species in the transmission of schistosomes in man and domestic stock is discussed. Recent ecological changes caused by the construction of dams at Diama and Mananatali on the Senegal River, such as reduction in salinity, more stable water flow, creation of irrigation canals and development and extension of rice culture, have contributed towards the occurrence of new outbreaks of both intestinal and urinary schistosomiasis in the Senegal River Basin. In Mali, the four main areas of high prevalence of S. haematobium are Office du Niger (irrigation areas), Bandiagara (small dams), Selingué (dam areas) and Baguineda (irrigation areas). Apart from the Office du Niger, S. mansoni infections are rare. Surveys were carried out in the Dogon Country (Bandiagara District) in an attempt to confirm the recent independent reports of the presence of S. intercalatum. Data based on egg morphology and Ziehl Neelsen staining of egg shells suggested the possible occurrence of S. haematobium x S. intercalatum hybrids. Potential factors affecting the focal endemicity of S. haematobium in Mali are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗