Biomedical subjects

Roel P Verkooyen

Publications and source records attributed to Roel P Verkooyen.

4 recordsLinked to original sources

PubMed2003

Chlamydia pneumoniae and the risk for exacerbation in multiple sclerosis patients.

In this prospective study of 73 relapsing remitting multiple sclerosis patients followed up for a mean of 1.7 years, the relation was tested between serologically defined Chlamydia pneumoniae (CP) infection periods and exacerbation rate. Episodes of serologically defined CP infections were observed in a subgroup, and these episodes were associated with increased risk for exacerbation. CP polymerase chain reaction was positive in most of the CP seropositive patients. No correlation was found between the anti-CP antibody increase and titers of control antibodies.

Adult↗

PubMed2003

Chlamydial LPS antibodies, intima-media thickness and ischemic events in patients with established atherosclerosis.

BACKGROUND: Chlamydia pneumoniae has been associated with cardiovascular disease. However, studies on the presence of chlamydial antibodies and intima-media thickness (IMT) or future ischemic events are inconclusive. We examined the relation between circulating antibodies to chlamydial lipopolysaccharide (cLPS Ab), IMT and the occurrence of ischemic events during follow-up in patients with manifest atherosclerotic disease. METHODS: IgG and IgA antibodies against cLPS were determined in 273 out of 307 consecutive patients with a recent ischemic stroke (IS, n=90), a recent myocardial infarction (MI, n=87) or peripheral arterial disease (PAD, n=96). B-mode ultrasound IMT measurement of carotid and femoral arteries was performed and ischemic events, IS or MI, during follow-up were registered. RESULTS: IgG and IgA were found in 66 and 46% of the patients, respectively. We did not detect any difference in IMT between patients with or without antibodies: IgA-0.97(0.28) mm versus IgA+0.95(0.26) mm, P=0.63, IgG-0.96(0.28) mm versus IgG+0.96(0.26) mm, P=0.98. During follow-up with a mean duration of 3.5 years the combined endpoint, MI or IS, was similar in patients with or without antibodies (IgA-24% vs. IgA+19%, IgG-23% vs. IgG+22%). However, a lower frequency of MI was observed in IgA positive patients (IgA-13% vs. IgA+8%). The number of ischemic events in the 12 patients who used anti-chlamydial antibiotics was similar compared with those who did not use antibiotics. CONCLUSION: In patients with manifest atherosclerotic disease no association between the presence of cLPS Ab and IMT could be detected. In addition, no influence of cLPS Ab on the number of ischemic events was observed, the frequency of MI during follow-up in IgA positive patients was even lower.

Aged↗

PubMed2003

Reliability of nucleic acid amplification methods for detection of Chlamydia trachomatis in urine: results of the first international collaborative quality control study among 96 laboratories.

The first European Quality Control Concerted Action study was organized to assess the ability of laboratories to detect Chlamydia trachomatis in a panel of urine samples by nucleic acid amplification tests (NATs). The panel consisted of lyophilized urine samples, including three negative, two strongly positive, and five weakly positive samples. Ninety-six laboratories in 22 countries participated with a total of 102 data sets. Of 204 strongly positive samples 199 (97.5%) were correctly reported, and of 506 weakly positive samples 466 (92.1%) were correctly reported. In 74 (72.5%) data sets correct results were reported on all samples, and 17 data sets (16.7%) showed either one false-negative or one false-positive result. In another 11 data sets, two or more incorrect results were reported, and two data sets reported a false-positive result on one negative sample. The Roche COBAS Amplicor test was performed in 44 (43%) data sets, the Abbott LCx assay was performed in 31 (30%) data sets, the Roche Amplicor manual assay was performed in 9 (9%) data sets, an in-house PCR was performed in 9 (9%) data sets, the Becton Dickinson ProbeTec ET assay was performed in 5 (4.9%) data sets, and the GenProbe TMA assay was performed in 4 (3.9%) data sets. The results of the Roche Amplicor manual (95.6% correct), COBAS Amplicor (97.0%), and Abbott LCx (94.8%) tests were comparable (P = 0.48). The results with the in-house PCR, BD ProbeTec ET, and GenProbe TMA tests were reported correctly in 88.6, 98, and 92.5% of the tests, respectively. Freeze-drying of clinical urine specimens proved to be a successful method for generating standardized, stable, and easy-to-transport samples for the detection of C. trachomatis by using NATs. Although the results, especially the specificity, for this proficiency panel were better than most quality control studies, sensitivity problems occurred frequently, underlining the need for good laboratory practice and reference reagents to monitor the performance of these assays.

Chlamydia Infections↗

PubMed2002

Foreword.

Explore the source record for details and available documents.

Journal Article↗