Biomedical subjects

Pieter Vos

Publications and source records attributed to Pieter Vos.

4 recordsLinked to original sources

PubMed2006

Prostate cancer localization with dynamic contrast-enhanced MR imaging and proton MR spectroscopic imaging.

PURPOSE: To prospectively determine the accuracies of T2-weighted magnetic resonance (MR) imaging, dynamic contrast material-enhanced MR imaging, and quantitative three-dimensional (3D) proton MR spectroscopic imaging of the entire prostate for prostate cancer localization, with whole-mount histopathologic section findings as the reference standard. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was obtained from all patients. Thirty-four consecutive men with a mean age of 60 years and a mean prostate-specific antigen level of 8 ng/mL were examined. The median biopsy Gleason score was 6. T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, and 3D MR spectroscopic imaging were performed, and on the basis of the image data, two readers with different levels of experience recorded the location of the suspicious peripheral zone and central gland tumor nodules on each of 14 standardized regions of interest (ROIs) in the prostate. The degree of diagnostic confidence for each ROI was recorded on a five-point scale. Localization accuracy and ROI-based receiver operating characteristic (ROC) curves were calculated. RESULTS: For both readers, areas under the ROC curve for T2-weighted MR, dynamic contrast-enhanced MR, and 3D MR spectroscopic imaging were 0.68, 0.91, and 0.80, respectively. Reader accuracy in tumor localization with dynamic contrast-enhanced imaging was significantly better than that with quantitative spectroscopic imaging (P < .01). Reader accuracy in tumor localization with both dynamic contrast-enhanced imaging and spectroscopic imaging was significantly better than that with T2-weighted imaging (P < .01). CONCLUSION: Compared with use of T2-weighted MR imaging, use of dynamic contrast-enhanced MR imaging and 3D MR spectroscopic imaging facilitated significantly improved accuracy in prostate cancer localization.

Aged↗

PubMed2004

SNPWave: a flexible multiplexed SNP genotyping technology.

Scalable multiplexed amplification technologies are needed for cost-effective large-scale genotyping of genetic markers such as single nucleotide polymorphisms (SNPs). We present SNPWave, a novel SNP genotyping technology to detect various subsets of sequences in a flexible fashion in a fixed detection format. SNPWave is based on highly multiplexed ligation, followed by amplification of up to 20 ligated probes in a single PCR. Depending on the multiplexing level of the ligation reaction, the latter employs selective amplification using the amplified fragment length polymorphism (AFLP) technology. Detection of SNPWave reaction products is based on size separation on a sequencing instrument with multiple fluorescence labels and short run times. The SNPWave technique is illustrated by a 100-plex genotyping assay for Arabidopsis, a 40-plex assay for tomato and a 10-plex assay for Caenorhabditis elegans, detected on the MegaBACE 1000 capillary sequencer.

Alleles↗

PubMed2004

Effect of prescribing a high protein diet and increasing the dose of dialysis on nutrition in stable chronic haemodialysis patients: a randomized, controlled trial.

BACKGROUND: Protein requirements in stable, adequately dialysed haemodialysis patients are not known and recommendations vary. It is not known whether increasing the dialysis dose above the accepted adequate level has a favourable effect on nutrition. The aim of this study was to determine whether prescribing a high protein diet and increasing the dose of dialysis would have a favourable effect on dietary protein intake and nutritional status in stable, adequately dialysed haemodialysis patients. Effects on hyperphosphataemia and acidosis were also studied. METHODS: Patients were randomized to a high dialysis dose (HDD) group (target Kt/V(eq) of 1.4) or a regular dialysis dose (RDD) group (target Kt/V(eq) of 1.0). All patients were prescribed a high protein (HP) diet [1.3 g/kg of ideal body weight (IBW)/day] and a regular protein (RP) diet (0.9 g/kg/day), each during 40 weeks in a crossover design. In 50 patients, 23 in the HDD and 27 in the RDD group follow-up was > or =10 weeks. These patients, aged 56+/-15 years, were included in the analysis. Nutritional status was assessed by anthropometry, plasma albumin and a nutritional index. RESULTS: Delivered Kt/V(eq) in the HDD group (1.26+/-0.14) was significantly higher than in the RDD group (1.02+/-0.08). Protein intake estimated from total nitrogen appearance (PNA) measurements and food records (DPI) was significantly higher during the HP diet (PNA(IBW), 1.01+/-0.18 g/kg/day; DPI(IBW), 1.15+/-0.18 g/kg/day) than during the RP diet (PNA(IBW), 0.90+/-0.14 g/kg/day; DPI(IBW), 0.94+/-0.11 g/kg/day). Increasing the dialysis dose did not increase protein intake either during the HP or RP diet. Plasma albumin (41.9+/-3.0 g/l) lean body mass (107+/-15% of normal values) and the nutritional index did not differ between the dialysis dose groups or protein diets and remained stable overtime. Dry body weight (97+/-14%) and total fat mass increased over time in the HDD group, but remained stable in the RDD group suggesting an effect of dialysis dose on energy balance. There was no effect of the protein diets on dry body weight or total fat mass. Plasma phosphate levels and oral bicarbonate supplements were lower in the HDD group, but were comparable between the protein diets. CONCLUSIONS: Prescribing a HP diet resulted in a modest increase in actual protein intake, but increasing dialysis dose did not have a contributing effect. A HP diet or increasing the dialysis dose did not have a favourable effect on the nutritional status. A dietary protein intake of at least 0.9 g/kg IBW/day appears to be sufficient for adequately dialysed haemodialysis patients without overt malnutrition.

Cross-Over Studies↗

PubMed2001

A controlled trial comparing two doses of cyclosporine in conjunction with mycophenolate mofetil and corticosteroids.

It is unknown whether the addition of mycophenolate mofetil (MMF) to cyclosporine (CsA) and prednisone after renal transplantation (RTx) allows for a reduced dose of CsA, to minimize the incidence of CsA-related side effects and to reduce costs. Therefore, 313 renal allograft recipients were randomized for treatment with MMF (1000 mg twice a day), prednisone, and either conventional- or low-dose CsA during the first 3 mo after RTx. The target trough levels were 300 and 150 ng/ml, respectively, during the first 3 mo and 150 ng/ml in both groups thereafter. A total of 313 patients were included: 161 patients received a conventional dose and 152 received a low dose of CsA. During the first 6 mo after RTx, graft failure or patient death occurred in 19 of 161 patients (12%) in the conventional-dose group and in 11 of 152 patients (7%) in the low-dose group (not significant). Biopsy-proven acute rejection occurred in 36 of 161 patients (22%) in the conventional-dose group and in 29 of 152 patients (19%) in the low-dose group (not significant). The incidence of delayed graft function was similar in both groups (31 of 161 [19%] versus 28 of 152 [18%]; not significant). Serum creatinine did not differ between the conventional- and the low-dose groups: 151 +/- 56 micromol/L versus 142 +/- 49 micromol/L at 3 mo and 141 +/- 60 micromol/L versus 136 +/- 49 micromol/L at 6 mo. There were no differences between the groups regarding BP, lipid metabolism, and infectious complications. In the low-dose group, an estimated $500 per patient was saved on the costs of CsA. In conclusion, the addition of MMF to CsA and prednisone after RTx allows the use of a lower-than-conventional dose of CsA, without increasing the risk of rejection.

Adrenal Cortex Hormones↗