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W Oosterhuis

Publications and source records attributed to W Oosterhuis.

10 recordsLinked to original sources
PubMed2003

Human tissue research: EORTC recommendations on its practical consequences.

Improvement in cancer care is possible by applying new treatment modalities, which are emerging from knowledge and discoveries coming from laboratory research. This is possible through international collaboration and the collection of tumour tissues. Creation of a European Organisation for Research and Treatment of Cancer (EORTC) Tumor Bank is a natural step in this direction, by offering tumour sample collection from patients entered in EORTC trials. The aim of such a bank is not only to improve the diagnostic review process, but also to facilitate translational research by allowing clinicians and basic scientists to enter into close collaborations. The EORTC Tissue Research Policy is developed to assure, under the EORTC legal framework, an ethical and scientific review of research projects, guarantee adequate information is given to patients, establish procedures on the use of materials, including legal aspects, and publication policies. Being part of the EU TubaFrost project, the EORTC will provide a common international platform for the use of tissues for research purposes, finding a balance between different laws and assuring scientific progress.

Clinical Trials as Topic↗
PubMed2002

The EORTC Laboratory Research Division. European Organisation for Research and Treatment of Cancer.

The Laboratory Research Division (LRD) of the EORTC currently consists of five Groups with expertise that includes pre-clinical drug development, all aspects of cancer pharmacology, clinically-relevant receptor and biomarker studies, functional imaging and contemporary pathology. The LRD provides a Europewide resource for cancer clinical trials with particular expertise in the evolving field of translational research. In the development of therapies designed to exploit the molecular and cellular pathology of cancer, it is essential that translational research is included at all stages and the EORTC, through the LRD, has access to such expertise. In addition to providing support for drug development and clinical trials, the LRD represents a unique forum for the development of contemporary translational research expertise, the establishment of quality standards and the education of young laboratory and clinical scientists embarking on careers in oncology.

Europe↗
PubMed2001

Reactivity of germ cell maturation stage-specific markers in spermatocytic seminoma: diagnostic and etiological implications.

It is generally accepted that testicular seminomas and spermatocytic seminomas have separate pathogeneses, although the origin of these two types of germ cell tumors of the adult testis remains a matter of debate. Although an embryonic germ cell origin seems to be most likely for seminomas, a spermatogonia-spermatocyte origin has been suggested for spermatocytic seminoma. To shed more light on the etiology of spermatocytic seminomas, we undertook an immunohistochemical and molecular approach using SCP1 (synaptonemal complex protein 1), SSX (synovial sarcoma on X chromosome), and XPA (xeroderma pigmentosum type A) as targets. Although a stage-specific expression pattern has been reported for SCP1 and SSX in normal spermatogenesis, we demonstrate here that it also exists for XPA. In fact, immunohistochemistry shows that the proteins of SCP1 and XPA are specifically present in the stage of primary and pachytene spermatocytes. In contrast, SSX was found in spermatogonia and primary spermatocytes, as well as in germ cells, from at least the 17th week of intrauterine development onward. Although no protein encoded by any of these genes was detected in tumor cells of a series of testicular seminomas, all tested spermatocytic seminomas were positive, in agreement with expression analysis. These data support the model that seminomas originate from an embryonic germ cell, and they imply that the cell of origin of spermatocytic seminomas is at least capable of maturing to the stage of spermatogonia-pachytene spermatocyte.

Antibody Specificity↗
PubMed2000

Comparative genomic and in situ hybridization of germ cell tumors of the infantile testis.

Chromosomal information on germ cell tumors of the infantile testis, ie, teratomas and yolk sac tumors, is limited and controversial. We studied two teratomas and four yolk sac tumors using comparative genomic hybridization (CGH) and in situ hybridization. No chromosomal anomalies were found in the teratomas by any of the methods, not even after CGH on microdissected tumor cells. All yolk sac tumors showed aneuploidy, loss of parts of 4q and 6q, and gain of parts of 20q. Underrepresentation of parts of 8q and overrepresentation of parts of 3p, 9q, 12p, 17, 19q, and 22 were detected in most cases. In addition, one recurrent yolk sac tumor after a sacral teratoma was studied, showing a highly similar pattern of imbalances. While CGH demonstrated loss of 1p36 in one testicular yolk sac tumor, in situ hybridization revealed loss of this region in all yolk sac tumors. High-level amplification of the 12q13-q14 region was found in one yolk sac tumor. MDM2, of which the encoding gene maps to this chromosomal region, was found in all cases using immunohistochemistry, whereas no p53 could be detected. Accordingly, no mutations within exons 5 to 8 of the p53 gene were observed. These data prove the absence of gross chromosomal aberrations in teratomas of the infantile testis and show a characteristic pattern of gains and losses in the yolk sac tumors. Besides confirmation of previously found anomalies, recurrent losses of 1p21-31 and 4q23-33 and gains of 9q34 and 12p12-13 have not been reported before. While genetic inactivation of p53 seems unimportant in the pathogenesis of these tumors, biochemical inactivation by MDM2 might be involved. These data support the existence of three entities of germ cell tumors of the human testis: teratomas and yolk sac tumors of infants, seminomas and nonseminomas of adolescents and young adults, and spermatocytic seminomas of the elderly, each with its own specific pathogenesis.

Aneuploidy↗
PubMed1999

Relationship between human papillomavirus type 16 in the cervix and intraepithelial neoplasia.

OBJECTIVE: To evaluate a temporal relationship between the presence of cervical human papilloma virus (HPV) type 16 and the risk of developing cervical intraepithelial neoplasia (CIN). METHODS: Fifty-four women with HPV 16 polymerase chain reaction (PCR)-positive tests were selected from the gynecologic outpatient clinic of the Reinier de Graaf Hospital, Delft, The Netherlands. At least three successive PCR tests were performed in each woman at intervals of 6 months. The PCR HPV 16 assay was performed in conjunction with cervical smear, and colposcopy and biopsy, if indicated. Women with at least three consecutive positive PCR tests were defined as having persistent HPV 16 infections. Women with one positive test followed by two negative tests were defined as having transient infections. Subdivided into two groups, 25 women had persistent infections and 29 had transient infections. RESULTS: In significantly more women in the persistent group compared with the transient group, CIN developed (11 of 25 versus six of 29, P = .036). Lesions in women with persistent HPV 16 infection were more severe (six of 11 were CIN III versus one of six P = .041). CONCLUSION: Persistent infection with HPV 16 is associated with a higher risk of developing CIN, which is often high-grade.

Adult↗
PubMed1998

Cytogenetic and molecular analysis of cellular atypical mesoblastic nephroma.

Cytogenetic and molecular analyses were performed on three cellular (atypical) congenital mesoblastic nephromas (CMNs). Two cases had trisomy 11; in one, it was the sole karyotypic abnormality, and the other had additional numerical changes as well as an isochromosome for the long arm of chromosome 1. Markers for the 11p13 and 11p15 loci were present in three copies in these two CMNs. In the third CMN, two apparently normal copies of chromosome 11 were present together with additional numerical and structural chromosome changes. Because loss of heterozygosity was observed for both 11p13 and 11p15 markers, we assume that mitotic recombination occurred. Duplication and loss of imprinting of genes at 11p15 has also been observed frequently in Wilms' tumor. We therefore propose that CMN and Wilms' tumor might share common genetic pathways.

Chromosome Banding↗
PubMed1997

Systematic reviewing in laboratory medicine. Position Paper from the IFCC Committee on Systematic Reviewing in Laboratory Medicine.

Each year a vast number of biomedical articles and books are published and based on the articles reviews are written. Such reviews should be performed in a systematic manner. Systematic reviewing is a new discipline with its own methods for locating, appraising, and summarizing primary studies. Such methods have also been developed for studies on diagnostic test evaluations. It is important for the laboratory disciplines to engage in this work. IFCC has established a Committee for Systematic Reviewing in Laboratory Medicine. This committee will work to promote the understanding, the use and the performance of systematic reviewing.

Clinical Chemistry Tests↗
PubMed1996

The influence of torque and velocity on erector spinae muscle fatigue and its relationship to changes of electromyogram spectrum density.

The influence of contraction force and velocity during isokinetic contractions on the development of fatigue in the erector spinae muscle was studied. Seven male subjects performed a series of 250 contractions at 25% and 50% of their isometric maximal voluntary contraction (MVC) at 40 and 80 degree.s-1. Fatigue defined as a decrease of the contractile capacity of the muscles was studied by means of a 15-s maximal test-contraction following the exercise. Both the initial force and the force decrement during the test-contraction were studied. Surface electromyogram (EMG) signals of the main tracts of the erector spinae muscle were recorded. The frequency content was studied by calculating the zero-crossing rate for the signals obtained during dynamic contractions and by means of fast Fourier transformation for the test contraction. After the 50% MVC dynamic contractions the initial force during the postexercise test-contraction was significantly lower than after the 25% MVC contractions. No significant influence of contraction velocity on fatigue development was found. The force decrement during the test-contraction did not depend on the experimental conditions. The EMG amplitude indicated that the subjects were better able to relax their muscles during the counter movement (flexion) at high forces and high velocities compared to the other experimental conditions. The frequency content of the EMG signals during the dynamic contractions and the postexercise test-contraction showed only very weak relationships with fatigue. Therefore, spectrum EMG parameters as determined in the present study do not seem suitable as indicators of muscle fatigue as a consequence of dynamic contractions of trunk extensor muscles.

Adult↗
PubMed1995

Cytogenetic evidence that carcinoma in situ is the precursor lesion for invasive testicular germ cell tumors.

A cytogenetic study of two cases of carcinoma in situ of the testis (CIS) and their adjacent invasive tumors, one a nonseminomatous germ cell tumor (NS) and one a seminoma (SE), revealed similarities in chromosomal pattern between the CIS and the invasive lesion in the same patient. These findings present for the first time cytogenetic evidence that CIS of the testis and its adjacent germ cell tumor are clonally related, which suggests that the CIS is indeed the precursor lesion of the invasive tumor.

Adult↗