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F Van Leeuwen

Publications and source records attributed to F Van Leeuwen.

5 recordsLinked to original sources
PubMed2006

Development of a national protocol to screen Dutch cancer survivors on late cancer treatment effects.

PURPOSES: The development of a national protocol to formalize the screening of Dutch cancer survivors on potential late cancer treatment effects and the medical terminology used in describing the patient follow up procedures. METHODS: A combined evidence-based and qualitative approach, the Glaser's State of the Art Strategy, was used to reach consensus on how to screen Dutch cancer survivors on late cancer treatment effects. A core working group set up a first proposal of a screening protocol and a handbook of medical term definitions by incorporating available research evidence (1980-2003), clinical expertise and definitions from Dutch medical dictionaries and textbooks. External experts reviewed this proposal in a cycle of two postal and two discussion rounds. The follow-up procedures and medical term definitions described in the draft screening protocol were to be accepted if consensus among external experts was > or =50%. RESULTS: A protocol for screening cancer survivors on late cancer treatment effects was developed describing the follow-up procedures for cancer survivors according to previous therapeutic exposures. Four hundred and twenty one medical terms were used in describing these follow-up procedures. One hundred and fifteen of these terms were classified as multi-interpretable and 101 of these terms were defined. No definitions could be found for the remaining 14 medical terms. CONCLUSIONS: We succeeded in reaching consensus throughout The Netherlands on a protocol to screen cancer survivors on late cancer treatment effects. This protocol is now in use by all Dutch outpatient clinics and warrants that the screening of cancer survivors is consistent across The Netherlands. The screening protocol specifies in detail how screening of cancer survivors should take place and can therefore be used by clinicians who were not involved in the consensus study.

Antineoplastic Protocols↗
PubMed2000

The development of a new information model for a pediatric cancer registry on late treatment sequelae in The Netherlands.

Worldwide, the need is felt for life time follow up of survivors of childhood cancer and for the establishment of registries of the late effects of pediatric oncology treatments. There is however little consensus about how this all should take place. For example, agreement on the nature of this follow up and the type of data to be collected in view of the earlier diagnosis and treatment of the patient is lacking. In a close collaboration between the 'Late Effects Study Group' (consisting of the Pediatric Oncology department of the Emma Children's Hospital and the department of Medical Oncology at the Academic Medical Center), the Netherlands Cancer institute/Antoni van Leeuwenhoek Hospital, and the department of Medical Informatics of the University of Amsterdam, consensus was reached on a new dataset on adverse late effects of pediatric oncology treatment. This dataset was used in developing an information model for the design of a computerized documentation system, PLEKsys. PLEKsys covers both standardized documentation of all relevant data items for evaluating late effects and review facilities on individual patient basis and on patient cohorts. We will install PLEKsys at all Dutch pediatric oncology centers and use the information model as a starting point in developing a National Pediatric Oncology Follow up Registry. A national programme encompassing all Dutch pediatric oncology centers has already been set up to co-ordinate the construction of this national registry.

Child↗
PubMed1996

Antigenic variation in trypanosomes.

We review here antigenic variation in African trypanosomes with emphasis on genetic mechanisms and on the expression sites in which the genes for Variant Surface Glycoproteins (VSGs) are expressed. There are multiple expression sites in a trypanosome, but only one of these is active at a time. We discuss recent experiments that provide new information on expression site regulation, i.e., how inactive sites are kept inactive and how the trypanosome switches from expression of one site to expression of another one. Trypanosomes can also change the gene expressed by replacing the gene in an active expression site by another VSG gene. This replacement involves the duplicative transposition of a silent VSG gene into the expression site. We present a model for the mechanism of this transposition that incorporates new features and that explains several unusual characteristics of the transposition process. We also discuss how new knowledge of nutrient uptake, notably uptake of host transferrin by trypanosomes, might be used for vaccine development.

Animals↗
PubMed1993

beta-D-glucosyl-hydroxymethyluracil: a novel modified base present in the DNA of the parasitic protozoan T. brucei.

We have previously shown that the DNA of the unicellular eukaryote T. brucei contains about 0.1% of a novel modified base, called J. The presence of J correlates with a DNA modification associated with the silencing of telomeric expression sites for the variant surface antigens of trypanosomes. Here we show that J is 5-((beta-D-glucopyranosyloxy)-methyl)-uracil (shortened to beta-D-glucosyl-hydroxymethyluracil), a base not previously found in DNA. We discuss putative pathways for the introduction of this base modification at specific positions in the DNA and the possible contribution of this modification to repression of surface antigen gene expression.

Animals↗