PubMed Health⌕ Search

Biomedical subjects

F Wuyts

Publications and source records attributed to F Wuyts.

13 recordsLinked to original sources
PubMed2006

Correlation between severity of sleep apnea and upper airway morphology based on advanced anatomical and functional imaging.

Determination of the apnea hypopnea index (AHI) as a measure of the severity of obstructive sleep apnea/hypopnea syndrome (OSAHS) is a widely accepted methodology. However, the outcome of such a determination depends on the method used, is time consuming and insufficient for prediction of the effect of all treatment modalities. For these reasons more methods for evaluating the severity of OSAHS, based on different imaging modalities, have been looked into and recent studies have shown that anatomical properties determined from three-dimensional (3D) computed tomography (CT) images are good markers for the severity of the OSAHS. Therefore, we correlated anatomical measurements of a 3D reconstruction of the upper airway together with flow simulation results with the severity of OSAHS in order to find a combination of variables to indicate the severity of OSAHS in patients. The AHI of 20 non-selected, consecutive patients has been determined during a polysomnography. All patients also underwent a CT scan from which a 3D model of the upper airway geometry was reconstructed. This 3D model was used to evaluate the anatomical properties of the upper airway in OSAHS patients as well as to perform computational fluid dynamics (CFD) computations to evaluate the airflow and resistance of this upper airway. It has been shown that a combination of the smallest cross-sectional area and the resistance together with the body mass index (BMI) form a set of markers that predict very well the severity of OSAHS in patients within this study. We believe that these markers can be used to evaluate the outcome of an OSAHS treatment.

Computer Simulation↗
PubMed2006

Test-retest reliability of the Dutch version of the Dizziness Handicap Inventory.

In the last fifteen years the Dizziness Handicap Inventory (DHI) has gained wide acceptance as a useful measure of handicap resulting from dizziness and unsteadiness. The objective of this study was to calculate measurement error and test-retest reliability of the Dutch version of the DHI. The translation into Dutch was performed according to a double translation method. One hundred and six patients with balance problems (range 26-78 years), scheduled for vestibular rehabilitation, completed the DHI on two occasions on the same day. The test-retest reliability was excellent, with Intraclass Correlation Coefficients ranging from 0.94 to 0.99 for DHI sub-scores and DHI total score. Most weighted kappa values (kappaW) exceeded 0.80 indicating substantial item per item test-retest reliability. Over 80% agreement was noted for all items except for item 8 (74%). Item 8 asks whether the subject feels dizzy or unsteady while doing ambitious activities like sports, dancing and household activities. Consequently measurement errors were calculated, suggesting that, after an intervention, the pretreatment DHI total score should at least decrease with 12 points (lower bound 99% confidence interval for a true change) before the intervention could be said to be effective for an individual patient. Based on these data, the Dutch version of the DHI showed itself to be a highly reliable instrument to assess the self-perceived handicap imposed by vestibular system diseases.

Adult↗
PubMed2003

Importance of methodology in determination of Chlamydia pneumoniae seropositivity in healthy subjects and in patients with coronary atherosclerosis.

Enzyme immunoassays (EIAs) for the detection of Chlamydia pneumoniae antibodies were compared to the microimmunofluorescence (MIF) test, the reference method. Furthermore, we assessed the hypothesis that a possible relationship between Chlamydia pneumoniae immunoglobulin G (IgG) antibodies and coronary artery disease is dependent on the type of EIA. Sera from 112 healthy men (mean age, 50.1 years) were tested for antibodies against Chlamydia pneumoniae by five commercial test kits: Focus Chlamydia MIF IgG test, Labsystems Chlamydia pneumoniae IgG EIA (LS EIA), R-Biopharm Elegance Chlamydia pneumoniae IgG EIA (RB EIA), Medac Chlamydia pneumoniae IgG sandwich enzyme-linked immunosorbent assay ELISA (MCp sELISA) and Medac Chlamydia IgG recombinant enzyme-linked immunosorbent assay ELISA (MC rELISA). Sera from 106 consecutive male patients (mean age, 63.6 years) undergoing diagnostic coronary angiography were also examined using the Focus MIF, LS EIA, MCp sELISA, and MC rELISA techniques. The agreement between LS EIA (65 to 83% [controls-patients]) or MC rELISA (49 to 61%) and Focus MIF (78 to 83%) was average to fair (kappa = 0.597 and 0.234, respectively). MCp sELISA and RB EIA showed good agreement with MIF (kappa = 0.686 and 0.665, respectively), with 80 to 89 and 79% of individuals reacting positively. A significant difference in seroprevalence between patients and healthy subjects was observed with the LS EIA, while seropositivities in the two study groups appeared equal when the Focus MIF assay was applied. The MC rELISA and MCp sELISA gave statistically significant differences in antibody seroprevalence in patients with two-vessel disease or when the patient group combined individuals with a two- or a three-vessel disease, respectively. The concordance between MIF and other commonly used serological assays for C. pneumoniae IgG antibody detection is good to fair. The choice of serological assay has important implications for C. pneumoniae antibody seroprevalence, as well as for the relationship between C. pneumoniae seropositivity and coronary artery disease.

Adult↗
PubMed2000

DFNA 2, 5, 8, 12.

Explore the source record for details and available documents.

Carrier Proteins↗
PubMed2000

Influence of surgical bladder reduction on urodynamic parameters: three techniques investigated in a rat model.

PURPOSE: Bladder wall wrapping and invagination have been used for the surgical treatment of the underactive detrusor and improvement of bladder emptying has been described. In a rat model we investigated the evolution in time of urodynamic parameters after 3 techniques of surgical bladder reduction. MATERIAL AND METHODS: Female Wistar rats underwent at random, a bladder reduction with vertical wrapping, the horizontal variant or invagination of the wall. Cystometry was performed before and 30 minutes after surgery, and after 1, 5 and 10 weeks. Sham operated animals had cystometries performed at day 1 and after 1, 5 and 10 weeks. At week 10 contraction of four differently orientated detrusor strips was examined in vitro. A histological study was done. RESULTS: Contraction pressure was not improved in vivo after 10 weeks follow-up. Capacity, despite an early significant reduction, became slightly higher than presurgery in both wrapping groups and even significantly higher in the invagination group. In each group residual volume almost doubled. In vitro some strips containing operated parts did contract more strongly than controls but not significantly. Strips which contain operated parts showed slightly increased fibrosis in the invagination and the vertical wrapping group and a huge amount of fibrosis in the horizontal wrapping group. CONCLUSIONS: This experiment indicated that the rationales behind the techniques of surgical bladder reduction are not correct. The partial successes in men may be explained by the original intrinsic deficiencies of the detrusor which prevent a secondary bladder enlargement as reaction to the volume reduction.

Animals↗
PubMed1999

Comparison of different voice samples for perceptual analysis.

Choice of voice sample material can influence perceptual judgments by a jury. The twofold purpose of this study was first to validate the pertinence of a sustained vowel for perceptual voice analysis in French speakers and second to test the hypothesis that use of only the stabilized portion of the vowel would lead to underestimation of dysphonia. Voice samples were recorded in 60 dysphonic patients and 20 normal controls. Three different sample materials were obtained for each subject, i.e. connected speech, a sustained vowel including both the initial and stable portion (complete sustained vowel), and a sustained vowel including only the stable portion (stabilized sustained vowel). The jury was composed of 7 experienced listeners. Jury consistency was measured as a percentage of agreeing judgments for the same subject. No difference in consistency was observed using the three sample materials. Judgments on stabilized sustained vowels were confirmed as less severe than judgments on connected speech. Judgments on complete sustained vowels were comparable to judgments on connected speech.

Adult↗
PubMed1998

Optimal parameters for transurethral intravesical electrostimulation determined in an experiment in the rat.

OBJECTIVE: Parameters of current for transurethral intravesical electrostimulation (IVES) are studied in the rat to determine the settings which elicit optimal detrusor contractions. Action mechanisms related to the induction of detrusor contractions upon ives are also investigated. METHODS: In 24 female Wistar rats transurethral IVES was performed using 95 combinations of different pulse durations and frequencies. The reference electrode was positioned in the bladder, in the urethra, or on the abdominal wall. RESULTS AND CONCLUSIONS: The optimal detrusor contractions are induced in the rat with a current of 10 Hz frequency and 20 ms pulse duration. A mathematical correlation is found between frequency and pulse duration which permits to determine the best combination. Evidence for the existence of local factors inducing detrusor contractions by IVES is given. The detrusor contractions proved independent of the position of the reference electrode.

Animals↗
PubMed1997

Slower recovery of muscle phosphocreatine in malignant hyperthermia-susceptible individuals assessed by 31P-MR spectroscopy.

Our aim was to develop an exercise protocol using 31P-magnetic resonance spectroscopy (31P-MRS), which can discriminate between malignant hyperthermia-susceptible (MHS) individuals and controls. MRS spectra of the forearm muscles were recorded at rest, during and after a standardized exercise protocol in 10 MHS patients and compared with spectra obtained in 10 controls. There was no difference in resting intracellular pH (pHi) or PCr/(Pi+PCr) ratio between the groups (PCr = phosphocreatine, Pi = inorganic phosphorus). At the end of the exercise and during the initial recovery phase, the pHi and PCr/(Pi+PCr) ratio were significantly lower in the MHS group ([pHi: 6.37 (0.07) for MHS vs 6.70 (0.05) for controls, P < 0.005; PCr/(Pi+PCr): 0.784 (0.017) for MHS vs 0.954 (0.020) for controls, P < 0.0005]). For PCr/(Pi+PCr), complete separation between the two groups was observed during the initial recovery phase. The mean recovery time of PCr/(Pi+PCr) was 0.57 min for the control group and 1.28 min for the MHS group. The slower recovery of PCr/(Pi+PCr) is likely to be caused by a combination of several factors, including the lower pHi in MHS subjects at the start of recovery (inhibiting ATP production) and excessive sarcoplasmic calcium overload (causing continued enzyme activation and ATP consumption). Our exercise protocol can be a valuable adjunct to discriminate between MHS and non susceptible subjects.

Adult↗
PubMed1997

Histomorphometric study of the normal middle ear mucosa. Preliminary results supporting the gas-exchange function in the postero-superior part of the middle ear cleft.

This study concerns the distance between the centre of gravity of blood vessels and the basement membrane of the middle ear cleft mucosa. The measurements were performed perpendicular to the long axis of the cross-section of the vessels, and revealed a significant difference between two regions of the middle ear cleft. At the level of the postero-superior part (epitympanum, aditus ad antrum, mastoid antrum and highest part of the mastoid air cells system), the distance between the blood vessels and the basement membrane of the mucosa was statistically shorter than in the antero-inferior part of the middle ear cleft. This indicates a privileged function of gaseous exchange of the postero-superior part of the middle ear cleft and may divide the middle ear cleft into different functional parts.

Aged↗
PubMed1997

[Comparison of different phonetic materials for perceptive analysis of dysphonia].

The authors describe a prospective study whose aim was to analyse the influence of the choice of phonetic material on the judgment of the panel. De Krom has already reported an experiment in which perceptive analysis showed that a sustained vowel was a useful material provided that the attack transitory was included (so called complete sustained vowel). He also showed that the panel gave more consistent results with speech or the complete sustained vowel than with the stable part of the sustained vowel. Our first objective was to find out whether we agreed with Krom's results, because for the study in the Dutch language to be applied to the French language, it was necessary to carry out an experimental validation given the cultural differences which might prejudice the results. In additional, we thought it likely that some acoustic information which was present in the attack transitories and was lacking in the stable part of the sustained vowel would run the risk of under-valuing the dysphonia in a study carried out on the stable part of sustained vowels. Our second objective was therefore to demonstrate that in cases of dysphonia, assessment based on the stable part of sustained vowels would be more lenient than those based on speech. The study was carried out using 80 voice samples from 60 dysphonic patients and 20 control subjects. The panel was made up of 7 experienced listeners. Agreement in the jury was judged by the percentage of identical responses given on 3 different presentations of each speech sample. This study showed no differences in the agreement of panel members over the three types of material by changing the severity of classification by the panel was analysed as follows: 1--Pearson r correlation coefficient, comparing on the one hand speech (the reference variable), and on the other samples of the complete vowel and the isolated stable part of the valve (tested variables). 2--A linear regression analysis. Our results confirm that assessments carried out on a sustain/vowel tend to cause a more lenient assessment than those carried out on speech. The assessment carried out on sustained vowels when the attack transient is included were of similar valued to those carried out using speech.

Adult↗
PubMed1995

Dexamethasone influences intimal thickening and vascular reactivity in the rabbit collared carotid artery.

Intimal thickening predisposes to atherosclerosis and is often associated with alterations of the vascular reactivity of the artery. We investigated whether dexamethasone inhibited the intimal thickening and reactivity changes induced by a silicone collar placed around the left rabbit carotid artery for 2 weeks. The sham-operated, right artery served as control. Dexamethasone (1 mg/kg/day), given in the drinking water (n = 10) or by a subcutaneous minipump (n = 10), abolished intimal thickening compared to that of both placebo groups (n = 10). Both dexamethasone and the collar suppressed the isometric force development of isolated segments elicited by KCl in organ chamber experiments. The collar raised the sensitivity to serotonin (5-hydroxytryptamine, 5-HT) and the maximum force development (Emax) after normalization for the KCl responses. Dexamethasone exerted complex effects on 5-HT contractions in sham arteries: the curves often became biphasic, and sensitivity and Emax of the first phase were depressed by dexamethasone. In contrast, dexamethasone raised the hypersensitivity of collared arteries to 5-HT even further. Collar and dexamethasone did not influence endothelium-dependent relaxations elicited by acetylcholine or the calcium ionophore A-23187. It is concluded that dexamethasone interfered with neo-intima formation in the collar model, presumably by inhibition of smooth muscle cell migration and/or proliferation, without restoring contractile behaviour. Therefore, the collar-induced alterations in the reactivity of the smooth muscle cells in the media appear to be unrelated to the process of intimal thickening.

Animals↗