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J J van Overbeeke

Publications and source records attributed to J J van Overbeeke.

At least 19 recordsLinked to original sources
PubMed2001

Subtyping of oligo-astrocytic tumours by comparative genomic hybridization.

Oligo-astrocytic tumours (OAs) histologically show both oligodendroglial and astrocytic differentiation. Unequivocal criteria for delineation of OAs from pure oligodendroglial (Os) and astrocytic (As) tumours and for grading of OAs are lacking. Molecular genetic analysis may allow for a better characterization of OAs and thereby guide prognostic and therapeutic decisions. Comparative genomic hybridization (CGH) was performed on 39 gliomas with variable phenotypic expression of histological features characteristic of both astrocytic and oligodendroglial differentiation. The results show that OAs are genetically more heterogeneous than Os. In addition to the "-1p/-19q" and "+7/-10" subtypes that have been previously recognized, two additional genetic subtypes, "intermediate" and "other", were identified in the present study. "Intermediate" OAs likely represent progression from "-1p/-19q" tumours. The "other" subtype appears to represent an additional, heretofore unrecognized, genetic pathway(s). Application of rigorously "strict" histopathological criteria, as opposed to "relaxed" criteria, for the selection of oligo-astrocytic tumours resulted in a higher percentage of "-1p/-19q" tumours, but some "-1p/-19q" tumours might be missed. The results suggest that molecular genetic analysis is a useful and valid additional tool for the classification of gliomas, particularly for the significant subset of tumours in which subjective histopathological criteria are insufficient for an unequivocal distinction between Os, As, and mixed OAs.

Adult↗
PubMed2000

[Cavernous sinus syndrome].

A clear and concise description and clinical interpretation of the cavernous sinus syndrome are lacking. Pathological changes in or around the cavernous sinus may lead to failure of eye muscle nerves and of one or more branches of the trigeminal nerve. The clinical signs of the cavernous sinus syndrome are combinations of failure of these cranial nerves sometimes with exophthalmus. Because many nerves can be wholly or partially involved in the syndrome, there is no clinical uniformity and the cavernous sinus syndrome has never been well defined. A neurotopographical classification is proposed in order to simplify the multiple interpretations of the cavernous sinus syndrome. The classical cavernous sinus syndrome is divided into three syndromes: the syndrome of the superior orbital fissure, the syndrome of the lateral wall of the cavernous sinus and the central cavernous sinus syndrome.

Cavernous Sinus↗
PubMed2000

PTEN mutation analysis in two genetic subtypes of high-grade oligodendroglial tumors. PTEN is only occasionally mutated in one of the two genetic subtypes.

We recently identified two genetic subtypes of high-grade oligodendroglial tumors (HG-OT): 1p-/19q- HG-OT are characterized by a loss of chromosome 1p32-36 (del(1)(p32-p36) and/or a del(19)(q13. 3); whereas +7/-10 HG-OT harbor a gain of chromosome 7 (+7) and/or a -10 without a loss of 1p32-36 and 19q13.3. Because a -10 and a +7 are most frequently detected in glioblastomas (GBM), the genotype of +7/-10 HG-OT suggests that these tumors are GBM with a prominent oligodendroglial phenotype rather than anaplastic oligodendrogliomas. PTEN is a tumor suppressor gene, located at 10q23.3, which is involved in tumor progression of GBM and other neoplasms. In this study, we screened for PTEN mutations in six low-grade oligodendroglial tumors (LG-OT), five 1p-/19q- HG-OT, seven +7/-10 HG-OT, and nine xenografted GBM. PTEN mutations were detected in none of the LG-OT and 1p-/19q- HG-OT, once in +7/-10 HG-OT, and frequently in GBM. As one of the +7/-10 HG-OT harbored a PTEN mutation, this demonstrates that PTEN can be involved in the oncogenesis of this genetic subtype of HG-OT. The lower frequency of PTEN mutations in +7/-10 HG-OT compared to GBM suggests that these tumors are of a distinct tumor type rather than GBM. Published by Elsevier Science Inc.

Brain Neoplasms↗
PubMed2000

Genetic reflection of glioblastoma biopsy material in xenografts: characterization of 11 glioblastoma xenograft lines by comparative genomic hybridization.

OBJECT: Human tumors implanted as subcutaneous xenografts in nude mice are widely used for the study of tumor biology and therapy. Validation of these models requires knowledge of the genetic makeup of the xenografts. The aim of this study was to establish whether chromosomal imbalances in 11 xenograft lines derived from human glioblastomas multiforme (x-GBMs) are similar to those found in GBM biopsy samples. The authors also studied genetic stability during serial passaging of three xenograft lines. METHODS: Chromosomal imbalances in x-GBMs were detected using comparative genomic hybridization (CGH). The authors compared the CGH results in x-GBMs with those in the original GBMs (o-GBMs) that were used to establish three of the xenograft lines and with the GBM biopsy results reported in the literature (1-GBMs). In three xenograft lines two different passages were analyzed. CONCLUSIONS: The results show that the chromosomal imbalances in x-GBMs are similar to those in o-GBMs and 1-GBMs, indicating that the GBM xenograft lines used were valid models from a genetic point of view. The CGH analysis of two different passages of three xenograft lines indicates that x-GBMs (like 1-GBMs) show intratumoral genetic heterogeneity and do not acquire chromosomal imbalances as a result of serial passaging.

Animals↗
PubMed1999

Effect of a modified Nd:YAG laser technique on neuroma formation: An experimental study in rat sciatic nerve.

BACKGROUND AND OBJECTIVES: Traumatic transection of a peripheral nerve is inherently associated with the development of neuroma at the end of the proximal stump, often leading to therapy-resistant pain. This study was designed to evaluate whether the neodymium:yttrium aluminum garnet (Nd:YAG) laser could prevent neuroma formation after neurectomy. STUDY DESIGN/MATERIALS AND METHODS: The sciatic nerves of 14 rats were diffuse coagulated by defocused Nd:YAG laser (12 W power), and subsequently transected with additional focused laser energy. The control group consisted of contralateral nerves transected by microscissors. The nerves were reexposed at different time intervals up to 9 weeks after surgery, and evaluation consisted of macroscopy, and light and transmission electron microscopy. RESULTS: True neuroma formation could not be observed after laser transection, and only five nerves formed a neuromatous bulb, with minimal adhesions to surrounding tissue. Microscissor transection resulted in widespread amputation neuromas, consisting of regenerating axons and connective tissue, and nervous tissue regenerating into surrounding tissue. Laser-transected nerves showed degenerative changes of the axons and myelin, while proliferation of Schwann cells could not be observed. No outgrowth of axons could be observed outside the coagulated proximal stump. An epi/perineurial layer was present, covering the nerve stumps. Microscissor-transected nerves showed proliferation of fibroblasts and Schwann cells, forming minifascicles, and vigorous outgrowth of axons into the tissue and even into the distal nerve stump. CONCLUSIONS: Within the limitations of this study it is concluded that the formation of amputation neuromas is suppressed by Nd:YAG laser application by thermal coagulation of the nerve and suppression of Schwann-cell proliferation.

Animals↗
PubMed1999

Surgical approach and histoanatomical aspects of the oculomotor nerve in rats.

The surgical approach and some histoanatomical characteristics of the intracavernous portion of the oculomotor nerve are described. Moreover, some perioperative precautions for intracranial surgical procedures in the rat are reported and the suitability of the rat as a model for studying intracranial nerve regeneration is discussed. With the data provided, this model of oculomotor nerve approach can be used to study various aspects of intracranial nerve regeneration.

Animals↗
PubMed1999

End-to-end versus peripheral nerve graft repair of the oculomotor nerve in rats: A comparative histological and morphometric study.

A comparative study was undertaken to evaluate end-to-end versus peripheral nerve graft repair in cranial nerve reconstruction. In 14 rats, the oculomotor nerve was sharply transected in the cavernous sinus and repaired either by end-to-end coaptation (n = 7) or by interposition of a peripheral nerve graft (n = 7). The results were evaluated 16 weeks after surgery by light and transmission electron microsurgery and by morphometric analysis. The degree of neuroma formation, fibrosis, and axonal disorganisation at the repair site was the same for both groups. Histologically, both end-to-end and graft repair groups revealed various degrees of axonal regeneration with myelinated nerve fibres in the distal nerve segments. In both groups, the number of nerve fibres distal to the repair site was increased compared to proximal to the repair (P < 0.001) but myelinated axon diameter was significantly less than that of control nerves (P < 0.001). No difference existed between the two repair groups in terms of mean myelinated axonal diameter. However, the number and density of myelinated axons was statistically greater in the graft group (P < 0.05). In conclusion, despite the disadvantage of two repair sites, peripheral nerve grafting results in equal or slightly superior axonal regeneration compared to an end-to-end repair in the rodent model of intracranial oculomotor nerve reconstruction. We speculate that this may be due to the structure of the peripheral nerve graft.

Animals↗
PubMed1999

On the mechanism of transient postoperative deficit of cranial nerves.

BACKGROUND: Transient cranial nerve deficit is a common postoperative complication after surgery at the cranial base. In this type of surgery, the cranial nerves are often not macroscopically damaged or transected, but more or less manipulated during surgery. In this article, the cellular mechanisms of postoperative cranial nerve deficit are reviewed. METHODS: Experimental and clinical papers concerning cranial and peripheral nerve damage during surgery were critically reviewed. RESULTS: There are definite differences in the anatomical and histological structure between peripheral and intracranial nerves, which make the latter much more prone to intraoperative damage. Several pathological mechanisms are responsible for postoperative deficit, such as segmental demyelination of the nerve, comprised microcirculation within the nerve, postoperative edema, and "synaptic stripping" around the cell bodies of the affected neurons, which can be regarded as a regenerative response of the nervous system. CONCLUSIONS: Several cellular mechanisms are responsible for postoperative cranial nerve deficit after skull base surgery. Understanding these mechanisms is important for all surgeons involved in the treatment of skull base lesions.

Cranial Nerve Diseases↗
PubMed1999

Identification of subgroups of high-grade oligodendroglial tumors by comparative genomic hybridization.

In contrast to astrocytic tumors, approximately two thirds of anaplastic oligodendrogliomas are reported to be chemosensitive. Relatively little is known about the genetic aberrations in oligodendroglial tumors (OTs). In order to elucidate oligodendroglial oncogenesis and to find specific genetic aberrations that may have prognostic and therapeutic implications, we performed comparative genomic hybridization (CGH) to detect chromosomal copy number changes in 17 low-grade OTs (LG-OTs) and 12 high-grade OTs (HG-OTs) lacking a prominent astrocytic component. Loss of chromosome 1p (79%) and 19q (76%) were most frequently detected by CGH, all LG-OTs and 50% of the HG-OTs contained -1p (including 1p36-32), -19q (including 19q13.3), or both, and the rest of the HG-OTs showed +7, -10, or both. Since losses of 1p36-32 and 19q13.3 were mutually exclusive with +7 or -10, the HG-OTs could be divided in -1p/-19q and +7/-10 tumors. While the -1p/-19q tumors can be considered as pure anaplastic oligodendrogliomas, the +7/-10 tumors may rather be glioblastomas with prominent oligodendroglial differentiation. We conclude that CGH is a powerful tool to assist in the identification of 2 major subgroups of HG-OTs with prognostic and possibly therapeutic relevance.

Chromosome Aberrations↗
PubMed1998

Protective coating of cranial nerves with fibrin glue (Tissucol) during cranial base surgery: technical note.

OBJECTIVE: Cranial nerve deficit, either transient or permanent, is a common postoperative complication after cranial base surgery. Frequently, this occurs because intracranial nerves are directly involved in the cranial base lesion. However, any cranial nerve adjacent to the lesion can be damaged because of direct or indirect manipulation during surgery, leading to severe morbidity. We describe a new technique in which the adjacent intracranial nerves are protected from surgical trauma by coating the nerves with a biological two-component fibrin glue (Tissucol; Immuno A.G., Vienna, Austria). SURGICAL TECHNIQUE: The technique was performed in patients who underwent cranial base surgery for different types of lesions. After exposure of the operating field, the cranial nerves that were at risk of operative trauma were coated with a thin layer of fibrin glue using a double lumen catheter within a traditional suction device. RESULTS: With the application of fibrin glue, a protective layer of a rubbery consistency is formed around the nerve. No intraoperative complications or adverse effects of the application were noted. Moreover, no surgical injury of the nerves occurred and no or minimal postoperative cranial nerve deficit was noted in the coated nerves. CONCLUSION: Although it is difficult to compare the postoperative cranial nerve deficit in the coated nerves with a control group, we think that this technique is a valuable method to minimize or avoid intraoperative cranial nerve injury during cranial base surgery.

Cranial Nerve Injuries↗
PubMed1998

Intracranial repair of a divided trochlear nerve. Case report.

The authors report the case of a 37-year-old woman in whom the trochlear nerve was transected during removal of a meningioma in the cavernous sinus and subsequently repaired by using microsurgical techniques. This patient presented with a tumor in the posterior part of the right cavernous sinus with expansion over the tentorium. Preoperatively, she suffered from partial deficit of the right trochlear nerve. Intraoperatively, the trochlear nerve was noted to be completely encased by the tumor and was totally divided during removal of the lesion. After tumor resection, the trochlear nerve was repaired by using a sural nerve fascicle secured with sutures and fibrin glue. Six months after the operation, trochlear nerve regeneration became evident as the patient's binocular vision gradually improved. The patient regained normal functioning of the superior oblique muscle 3.5 years after surgery. It is concluded that repair of a divided trochlear nerve is worthwhile and can be followed by successful regeneration and an excellent functional recovery of the superior oblique muscle.

Adult↗
PubMed1998

Falcine sinus and occipital encephalocele: a magnetic resonance venography study.

OBJECT: Occipital encephaloceles are relatively frequently encountered. Many investigators have addressed the embryogenesis of these formations, but the dural system has never before been studied. In this retrospective analysis the authors sought to gain a better understanding of the origins of these defects. METHODS: The charts and radiological examinations, especially the magnetic resonance venography studies, were reviewed in seven patients. In six patients the straight sinus was absent. Drainage of the galenic system took place through a sinus within the falx, also known as a falcine sinus. The tentorium was not seen in five patients. CONCLUSIONS: The combination of an absent straight sinus and dysplastic tentorium is no coincidence: both develop within the same mesenchyme in the mesencephalic flexure. Distortion of the mesenchyme by a neural tube defect, causing an occipital encephalocele, will lead not only to disorders of the tentorium but also of the straight sinus.

Adult↗
PubMed1997

Lumbar cerebrospinal fluid drainage for symptomatic sacral nerve root cysts: an adjuvant diagnostic procedure and/or alternative treatment? Technical case report.

OBJECTIVE AND IMPORTANCE: The treatment of symptomatic sacral nerve root cysts is difficult and challenging. A major role has been ascribed to the hydrostatic and pulsatile forces of cerebrospinal fluid (CSF) for the symptomatology of sacral nerve root cysts. Theoretically, lowering those pressures should have a beneficial effect on the symptoms. Lowering the hydrostatic and pulsatile pressures may be achieved by lumbar CSF drainage. The effect of lumbar CSF drainage on the symptomatology of sacral nerve root cysts is described. CLINICAL PRESENTATION: Three patients suffered from leg and/or low back pain as a result of sacral nerve root cysts. INTERVENTION: First, CSF was drained through an external lumbar drain that was connected to a CSF bag. Mobilization was not restricted. All patients became free of symptoms. Eventually, a lumboperitoneal shunt was inserted in two patients. Those two patients remained free of complaints for 11 and 9 months, respectively. CONCLUSION: To our knowledge, this is the first report that clearly establishes the role of CSF forces in the symptomatology of sacral nerve root cysts. Lumbar external CSF drainage is a diagnostic tool to investigate the clinical significance of sacral nerve root cyst(s). Lumboperitoneal CSF shunting is a promising alternative in the treatment of symptomatic sacral nerve root cysts.

Back Pain↗
PubMed1997

Charles Labbé (1851-1889).

The vein of Labbé is a very important structure and every neurosurgeon is acquainted with its anatomy. Because of the recent increasing interest and experience in skull base surgery, the vein of Labbé has received a great deal of attention. Intraoperative damage to this vein should be avoided and several methods to prevent this have been described. Despite these developments, nothing is written in the neurosurgical literature about the man who described this vein for the first time: Charles Labbé. The authors therefore conducted an extensive search of the literature and uncovered several public records in France to learn more about Charles Labbé.

France↗