Biomedical subjects

Ton Feuth

Publications and source records attributed to Ton Feuth.

6 recordsLinked to original sources

PubMed2006

A new motor performance test in a prospective study on children with suspected myopathy.

In the development of a new diagnostic motor performance test to spare more children from painful muscle biopsy, seven functional items were used to measure muscle strength and muscle endurance in a prospective study on new patients. Over a 2-year period, 22 patients (12 males, 10 females; mean age 8y 1mo [SD 2y 6mo], range 4-11y) were recruited for the study. They had all been referred with suspected myopathy. The motor performance test was administered before muscle biopsy. Validity of the seven items was assessed using logistic regression analysis and receiver operating characteristic (ROC) analysis. Two items were withdrawn from the test because they were not suitable for children aged 4 to 5 years. The five remaining items were: Heels, Circuit, Stairs, Jump, and Gowers. A full logistic regression model including these five items was fitted to the total population of 90 patients suspected of having myopathy (from this study and our previous study) to make the best prediction of whether myopathy was present. The ROC area under the curve of the diagnostic prediction model was 0.92 (95% confidence interval [CI] 0.87-0.98) and 0.89 (95% CI 0.87-0.92) after bootstrap correction. This indicated the high diagnostic power that can be expected for future, similar patients. This non-invasive and child-friendly motor performance test can improve diagnostic procedure and, therefore, spare more children from unnecessary muscle biopsy.

Biopsy↗

PubMed2006

Subsidence of stand-alone cervical carbon fiber cages.

OBJECTIVE: To investigate the number of subsidences of inserted cervical carbon fiber cages and to define predictive factors for subsidence. METHODS: All patients treated for a cervical herniated disc and fusion with a cervical carbon fiber cage between January 2002 and December 2003 were retrospectively identified. The radiological examinations were reviewed, and, especially, the presence of subsidence was noted. Possible predictive factors for subsidence were determined before the investigation. RESULTS: In 69 patients, there were 96 cages inserted, of which 29.2% subsided. Of all factors investigated, only smoking seemed to be predictive for subsidence, whereas insertion at C6 to C7 clearly had a higher risk at subsidence. Subsidence was not related to outcome or fusion. CONCLUSION: Although the high number of subsidence of cages has never been described before, clinical outcome and fusion rate is comparable with the literature.

Adult↗

PubMed2005

Diagnostic genome profiling in mental retardation.

Mental retardation (MR) occurs in 2%-3% of the general population. Conventional karyotyping has a resolution of 5-10 million bases and detects chromosomal alterations in approximately 5% of individuals with unexplained MR. The frequency of smaller submicroscopic chromosomal alterations in these patients is unknown. Novel molecular karyotyping methods, such as array-based comparative genomic hybridization (array CGH), can detect submicroscopic chromosome alterations at a resolution of 100 kb. In this study, 100 patients with unexplained MR were analyzed using array CGH for DNA copy-number changes by use of a novel tiling-resolution genomewide microarray containing 32,447 bacterial artificial clones. Alterations were validated by fluorescence in situ hybridization and/or multiplex ligation-dependent probe amplification, and parents were tested to determine de novo occurrence. Reproducible DNA copy-number changes were present in 97% of patients. The majority of these alterations were inherited from phenotypically normal parents, which reflects normal large-scale copy-number variation. In 10% of the patients, de novo alterations considered to be clinically relevant were found: seven deletions and three duplications. These alterations varied in size from 540 kb to 12 Mb and were scattered throughout the genome. Our results indicate that the diagnostic yield of this approach in the general population of patients with MR is at least twice as high as that of standard GTG-banded karyotyping.

Adolescent↗

PubMed2005

Eustachian tube function before recurrence of otitis media with effusion.

OBJECTIVE: To study the role of eustachian tube function in the development of recurrent otitis media with effusion (OME) in children treated with tympanostomy tubes for OME. DESIGN: Prospective cohort study. SETTING: Three academic and general hospitals. PATIENTS: Children aged 2 to 7 years with a first clinical episode of OME that persisted for at least 3 months; 136 (81%) of 168 eligible children participated. All children received tympanostomy tubes for bilateral OME at study entry. MAIN OUTCOME MEASURE: Recurrence of OME within 6 months of tube extrusion. RESULTS: No statistically significant differences were present in eustachian tube function test results between ears that developed recurrent OME and those that did not. The difference in passive ventilatory function between ears with and without OME recurrence was 10 daPa (95% confidence interval, -24 to 43 daPa) for opening pressure and -3 daPa (95% confidence interval, -18 to 11 daPa) for closing pressure. The overall difference in the proportion of ears with and without OME recurrence that could not equilibrate positive and negative applied pressures was 12% (95% confidence interval, -2% to 26%). The proportions of ears with and without OME recurrence that induced negative pressure in the middle ear by forcefully sniffing were 22% and 31%, respectively (P = .75). CONCLUSION: Measurement of ventilatory and protective eustachian tube function using the forced response test, the pressure equilibration test, and the sniff test has no value in predicting whether children have an increased risk of OME recurrence.

Child, Preschool↗

PubMed2005

Normalization of gene expression measurements in tumor tissues: comparison of 13 endogenous control genes.

For interpretation of quantitative gene expression measurements in clinical tumor samples, a normalizer is necessary to correct expression data for differences in cellular input, RNA quality, and RT efficiency between samples. In many studies, a single housekeeping gene is used for normalization. However, no unequivocal single reference gene (with proven invariable expression between cells) has been identified yet. As the best alternative, the mean expression of multiple housekeeping genes can be used for normalization. In this study, no attempt was made to determine the gold-standard gene for normalization, but to identify the best single housekeeping gene that could accurately replace the measurement of multiple genes. Expression patterns of 13 frequently used housekeeping genes were determined in 80 normal and tumor samples from colorectal, breast, prostate, skin, and bladder tissues with real-time quantitative RT-PCR. These genes included, large ribosomal protein, beta-actin, cyclophilin A, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerokinase 1, beta-2-microglobin, beta-glucuronidase, hypoxanthine ribosyltransferase (HPRT), TATA-box-binding protein, transferrin receptor, porphobilinogen deaminase, ATP synthase 6, and 18S ribosomal RNA. Principal component analysis was used to analyze these expression patterns, independent of the level of expression. Our approach identified HPRT as the single best reference gene that could be used as an accurate and economic alternative for the measurement of multiple housekeeping genes. We recommend this gene for future studies to standardize gene expression measurements in cancer research and tumor diagnostics until a definite gold standard has been determined.

Adenocarcinoma↗

PubMed2003

Array-based comparative genomic hybridization for the genomewide detection of submicroscopic chromosomal abnormalities.

Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using approximately 3,500 flourescent in situ hybridization-verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome.

Chromosome Aberrations↗