Biomedical subjects

C Dirven

Publications and source records attributed to C Dirven.

7 recordsLinked to original sources

PubMed2006

Human adenovirus type 35 vector for gene therapy of brain cancer: improved transduction and bypass of pre-existing anti-vector immunity in cancer patients.

Clinical trials in malignant glioma have demonstrated excellent safety of recombinant adenovirus type 5 (Ad5) but lack of convincing efficacy. The overall low expression levels of the Coxsackie and Adenovirus receptor and the presence of high anti-Ad5-neutralizing antibody (NAb) titers in the human population are considered detrimental for consistency of clinical results. To identify an adenoviral vector better suited to infect primary glioma cells, we tested a library of fiber-chimeric Ad5-based adenoviral vectors on 12 fresh human glioma cell suspensions. Significantly improved marker gene expression was obtained with several Ad5-chimeric vectors, predominantly vectors carrying fiber molecules derived from B-group viruses (Ad11, Ad16, Ad35 and Ad50). We next tested Ad35 sero prevalence in sera derived from 90 Dutch cancer patients including 30 glioma patients and investigated the transduction efficiency of this vector in glioma cell suspensions. Our results demonstrate that the sero prevalence and the titers of NAb against Ad35 are significantly lower than against Ad5. Also, recombinant Ad35 has significantly increased ability to transfer a gene to primary glioma cells compared to Ad5. We thus conclude that Ad35 represents an interesting candidate vector for gene therapy of malignant glioma.

Adenoviridae↗

PubMed1993

Shunting normal pressure hydrocephalus: the predictive value of combined clinical and CT data.

The value of an ordinal global scale derived from combined clinical and CT data (clin/CT scale) to predict the clinical outcome in 112 patients shunted for presumed normal pressure hydrocephalus (NPH) was analysed. The clinical data were retrospectively collected, all CT scans were re-evaluated, and the clin/CT scale was determined blind to the results of further ancillary tests and to the post-surgical outcome. The scale ranked three classes of prediction: on the basis of clinical and CT characteristics, improvement after shunting was probable, possible, or improbable. The predictive value of the clin/CT scale for the subgroup of communicating NPH was established for two different strategies, depending on the strictness of selection criteria for shunting. In the subgroup of patients with presumed communicating NPH, the prevalence of shunt responsiveness was 29%; the best strategy was to shunt only patients with probable shunt-responsive NPH: the sensitivity was 0.54, the specificity 0.84, and the predictive accuracy 0.75, with a limited number of ineffective shunts (11%) and missed improvements (13%). The study illustrates its need to assess the pre-test probability of NPH based on combined clinical and CT data, before establishing the clinical usefulness of an ancillary test.

Aged↗

PubMed1992

Normal-pressure hydrocephalus. Is cisternography still useful in selecting patients for a shunt?

The clinical usefulness of cisternography in selecting patients with presumed normal-pressure hydrocephalus for shunting was investigated in 76 patients. The predictive value of a scale based on combined clinical and computed tomographic criteria was first established, followed by an assessment of the predictive value of cisternography. Predictions based on cisternograms were identical to those of the clinical/computed tomographic scale in 43%, better in 24%, and worse in 33%. Our findings suggest that cisternography does not improve the diagnostic accuracy of combined clinical and computed tomographic criteria in patients with presumed normal-pressure hydrocephalus.

Cerebral Ventriculography↗

PubMed1992

Shunting normal-pressure hydrocephalus: do the benefits outweigh the risks? A multicenter study and literature review.

We performed a multicenter retrospective study in 166 consecutive patients shunted for presumed normal-pressure hydrocephalus (NPH) in the four neurosurgical departments of Amsterdam. Overall improvement occurred in 36%, substantial improvement in 21%. In the subgroup of idiopathic NPH (N = 127), marked improvement was only 15%. The incidence of shunt-responsive NPH in our area was 2.2/million/year. The rate of severe and moderate shunt-related complications was 28%, leading to death or severe residual morbidity in 7%. The substantial benefit/serious harm ration in the whole group was only three (21%/7%), decreasing to 1.7 in idiopathic NPH. By excluding patients at high surgical risk, this ratio might have risen to 10 in the whole group and to six in idiopathic NPH. Our experience is much less favorable than that encountered in the literature, reporting overall improvement in 74% and marked improvement in 55% of the shunted patients. We conclude that NPH is probably a very rare and still overdiagnosed syndrome and that the overall morbidity rate for each patient demonstrating meaningful improvement is high.

Adult↗

PubMed1985

Chronotopographical potential distribution of some SSEP components in cerebrovascular insufficiency.

In 7 patients with symptoms of cerebrovascular diseases a somatosensory evoked potential (SSEP) chronotopogram was constructed after median nerve stimulation of seven different EP components: N20, P25, P45, P100, N140, P200 and P300. We examined only a limited number of patients (and controls) because the methodology is very time-consuming. We analyzed the topography in these patients in order to obtain insight in the effect of this disease on EP distributions and to find arguments in favor of the use of this methodology in clinical examination. These chronotopographical maps were constructed on the basis of the localization of maximal amplitude of the different components and their dipole counterparts (if present). 3 patients showed a delay of the specific components, and in 1 patient most of the non-specific components were delayed. The chronotopographical representation in most patients was abnormal. Relations with clinical state and computer tomography (CT) are described. Focal hypodensity on the CT gives rise to a large extension of the area of the specific component N20, overruling the dipole counterpart P20. Slight cortical atrophy in 4 patients causes abnormalities in the P300/N300 dipole direction. Chronotopograms give new information. Therefore, it seems justified to improve the method and implement it for clinical use in the near future.

Adult↗

PubMed1985

[Somatosensory chronotopography: normative data].

Somatosensory chronotopography of a limited number of components gives a simple representation of the potential distribution of evoked potentials over the skull. Components of individual somatosensory evoked potentials over 16 equally distributed electrodes were analysed in 10 healthy volunteers. The distribution of some specific and non-specific components, as found near the somatosensory cortex is defined and the distribution in relation to the individual traces plotted, resulting in seven normative topogramms with 90% appearance area of maxima of the seven different components. Dipoles are often present.

Adult↗

PubMed1984

SSEP chronotopography in patients with multiple sclerosis.

In 10 patients with definite MS, an SSEP chronotopogram was constructed of 7 different, well-defined components: N20, P25, P45, P100, N140, P200 and P300. Chronotopographical maps were constructed on the basis of the localization of maximal amplitudes of the different components and their dipolar counterparts (when present). Most patients showed a delay of different specific as well as aspecific components. The chronotopogram was not much different from normal except for P45. Most generators therefore seem to stay stable. One of the P45 dipole generators vanished, probably due to a slight change in its direction, or more probably as a consequence of loss of association fibres in the cortical white matter. Spatio-temporal mapping provides new, clinically relevant information. The development of automatic methods for this mapping is justified for routine clinical use in neurology.

Adult↗