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J M Kros

Publications and source records attributed to J M Kros.

At least 19 recordsLinked to original sources
PubMed2007

Raman spectroscopic characterization of porcine brain tissue using a single fiber-optic probe.

Accurate targeting of diseased and healthy tissue has significantly been improved by MRI/CT-based navigation systems. Recently, intraoperative MRI navigation systems have proven to be powerful tools for the guidance of the neurosurgical operations. However, the widespread use of such systems is held back by the costs, the time consumption during operation, and the need for MR-compatible surgical devices. Raman spectroscopy is a nondestructive optical technique that enables real-time tissue identification and classification and has proved to be a powerful diagnostic tool in a large number of studies. In the present report, we have investigated the possibility of distinguishing different brain structures by using a single fiber-optic probe to collect Raman scattered light in the high-wavenumber region of the spectrum. For the Raman measurements, 7 pig brains were sliced in the coronal plain and Raman spectra were obtained of 11-19 anatomical structures. Adjacent brain structures could be distinguished based on their Raman spectra, reflecting the differences in their biochemical composition and illustrating the potential Raman spectroscopy holds as a guidance tool during neurosurgical procedures.

Animals↗
PubMed2006

Frameshift proteins in autosomal dominant forms of Alzheimer disease and other tauopathies.

Frameshift (+1) proteins such as APP(+1) and UBB(+1) accumulate in sporadic cases of Alzheimer disease (AD) and in older subjects with Down syndrome (DS). We investigated whether these proteins also accumulate at an early stage of neuropathogenesis in young DS individuals without neuropathology and in early-onset familial forms of AD (FAD), as well as in other tauopathies, such as Pick disease (PiD) or progressive supranuclear palsy (PSP). APP(+1) is present in many neurons and beaded neurites in very young cases of DS, which suggests that it is axonally transported. In older DS patients (>37 years), a mixed pattern of APP(+1) immunoreactivity was observed in healthy looking neurons and neurites, dystrophic neurites, in association with neuritic plaques, as well as neurofibrillary tangles. UBB(+1) immunoreactivity was exclusively present in AD type of neuropathology. A similar pattern of APP(+1) and UBB(+1) immunoreactivity was also observed for FAD and much less explicit in nondemented controls after the age of 51 years. Furthermore, we observed accumulation of +1 proteins in other types of tauopathies, such as PiD, frontotemporal dementia, PSP and argyrophylic grain disease. These data suggest that accumulation of +1 proteins contributes to the early stages of dementia and plays a pathogenic role in a number of diseases that involve the accumulation of tau.

Adult↗
PubMed2006

Molecular misreading: the occurrence of frameshift proteins in different diseases.

Neuronal homoeostasis requires a constant balance between biosynthetic and catabolic processes. Eukaryotic cells primarily use two distinct mechanisms for degradation: the proteasome and autophagy of aggregates by the lysosomes. We focused on the UPS (ubiquitin-proteasome system). As a result of molecular misreading, misframed UBB (ubiquitin B) (UBB+1) is generated. UBB+1 accumulates in the neuritic plaques and neurofibrillary tangles in all patients with AD (Alzheimer's disease) and in the neuronal and glial hallmarks of other tauopathies and in polyglutamine diseases such as Huntington's disease. UBB+1 is not present in synucleinopathies such as Parkinson's disease. We showed that UBB+1 causes UPS dysfunction, aggregation and apoptotic cell death. UBB+1 is also present in non-neurological cells, hepatocytes of the diseased liver and in muscles during inclusion body myositis. Other frequently occurring (age-related) diseases such as Type 2 (non-insulin-dependent) diabetes mellitus are currently under investigation. These findings point to the importance of the UPS in diseases and open new avenues for target identification of the main players of the UPS. Treatment of these diseases with tools (e.g. viral RNA interference constructs) to intervene with specific targets is the next step.

Amino Acid Sequence↗
PubMed2005

Primitive neuroectodermal tumours (PNETs) located in the spinal canal; the relevance of classification as central or peripheral PNET : case report of a primary spinal PNET occurrence with a critical literature review.

Intraspinal location of central PNET (cPNET) is very rare. We present a case, critically review all publications of primary intraspinal cPNET occurrence and discuss tendencies in clinical presentation. In several previous attempts to summarise, authors often confused cPNET with peripheral PNET (pPNET). cPNET and pPNET are different entities with different immunohistochemical profiles and genetic backgrounds. Clinically, they are both aggressive tumours, but exhibit different characteristics in their local manifestation and metastatic spread. Survival rates are quite similar provided that treatment is applied according to the established protocols. Protocols in cPNET treatment differ from those for pPNET as regards the order of the treatment sub-modalities, specific chemotherapeutic regimen and intensity, radiation dose and its extent and consequently, the side effects. Therefore, failure to distinguish cPNET from pPNET leads to clinical guidance and treatment proposals based on false assumptions, which might effect outcomes. Often, distinguishing between cPNET and pPNET is easy, because they occur in different location. In the case of intraspinal tumour location, however, the differentiation is crucial because both primary cPNET and pPNET can occur intraspinally, even though this is rare. Nowadays, demonstrating the expression of MIC2 glycoprotein by immunocytochemical staining (CD99) showing the specific EWS-FLI1 chimeric gene presence in pPNET, offers an easy way of making a differential diagnosis between cPNET and pPNET.

12E7 Antigen↗
PubMed2005

[The oligodendroglioma: the value of histologic and genetic diagnosis in predicting sensitivity to chemotherapy].

During the past decade, there has been increasing interest in oligodendrogliomas because of their sensitivity to chemotherapy. However, making the histopathological diagnosis suffers from subjectivity in many cases. Oligodendrogliomas possess a 'genetic signature' that correlates well with the sensitivity of the tumour to chemotherapy, namely, the loss of parts of chromosome arms 1p and 19q. Hence, in cases of oligodendroglial tumors with disputable histology, additional genotyping to reveal losses on 1p/19q has become a valuable addition for making decisions for treatment.

Brain Neoplasms↗
PubMed2005

[Favourable result for temozolomide in recurrent high-grade glioma].

OBJECTIVE: To describe the results of the treatment of recurrent glioma with temozolomide. DESIGN: Retrospective. METHOD: This study evaluated 77 patients with a recurrent high-grade glioma who from August 1997-December 2003 were treated with temozolomide (150-200 mg/m2/day for 5 days per 28-day cycle) following surgery and radiotherapy at the Daniel den Hoed Oncology Centre of the Erasmus MC, Rotterdam, the Netherlands. The patients were divided into 4 groups depending on histology and chemotherapy history. RESULTS: 15 patients received temozolomide for a recurrent anaplastic oligodendroglioma or mixed oligo-astrocytoma. The response in this group was 80% and after 12 months in 47% of the patients there was no disease progression. 35 patients underwent second-line chemotherapy with temozolomide after earlier chemotherapy with procarbazine, lomustine and vincristine for recurrent anaplastic oligodendroglioma or mixed oligo-astrocytoma. Response was 26% and after 12 months in 15% of patients there was still no disease progression. 14 patients were treated with temozolomide for a recurrent anaplastic astrocytoma with a response of 35% and after 12 months in 8% of these patients there was no disease progression. Of the 13 patients with a recurrent glioblastoma who were treated with temozolomide 16% responded and after 6 and 12 months 21% were still free from progression. Temozolomide was well-tolerated: 2 patients had to stop because of probable side effects. CONCLUSION. Temozolomide has an acceptable safety profile and may be regarded as the preferred treatment for recurrent anaplastic gliomas after radiotherapy. There is only a limited role for temozolomide in the treatment of recurrent glioblastoma.

Adult↗
PubMed2004

Salvage PCV chemotherapy for temozolomide-resistant oligodendrogliomas.

The authors investigated the results of PCV chemotherapy within a cohort of 24 patients treated within the EORTC study 26971 on temozolomide chemotherapy in recurrent oligodendroglioma. The genotype of the tumors was assessed with fluorescent in situ hybridization with locus specific probes for the region 1p36. Four of the 24 patients responded (17%). Fifty percent of patients were still free from progression at 6 months and 21% were free from progression at 12 months. Although a clear relation existed between loss of 1p and response to temozolomide chemotherapy, this relation was absent in salvage PCV chemotherapy.

Adult↗
PubMed2004

Correlation of in vitro infiltration with glioma histological type in organotypic brain slices.

Diffuse invasion of the brain, an intrinsic property of gliomas, renders these tumours incurable, and is a principal determinant of their spatial and temporal growth. Knowledge of the invasive potential of gliomas is highly desired in order to understand their behaviour in vivo. Comprehensive ex vivo invasion studies including tumours of different histological types and grades are however lacking, mostly because reliable physiological invasion assays have been difficult to establish. Using an organotypic rodent brain slice assay, we evaluated the invasiveness of 42 grade II-IV glioma biopsy specimens, and correlated it with the histological phenotype, the absence or presence of deletions on chromosomes 1p and 19q assessed by fluorescent in situ hybridisation, and proliferation and apoptosis indices assessed by immunocytochemistry. Oligodendroglial tumours with 1p/19q loss were less invasive than astrocytic tumours of similar tumour grade. Correlation analysis of invasiveness cell proliferation and apoptosis further suggested that grade II-III oligodendroglial tumours with 1p/19q loss grow in situ as relatively circumscribed compact masses in contrast to the more infiltrative and more diffuse astrocytomas. Lower invasiveness may be an important characteristic of oligodendroglial tumours, adding to our understanding of their more indolent clinical evolution and responsiveness to therapy.

Animals↗
PubMed2003

Phase II study of first-line chemotherapy with temozolomide in recurrent oligodendroglial tumors: the European Organization for Research and Treatment of Cancer Brain Tumor Group Study 26971.

PURPOSE: Oligodendroglial tumors are chemotherapy-sensitive tumors, with two thirds of patients responding to combination chemotherapy with procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ), a new alkylating and methylating agent, has demonstrated high response rates in patients with recurrent anaplastic astrocytoma. We investigated TMZ as first-line chemotherapy in recurrent oligodendroglial tumors (OD) and mixed oligoastrocytomas (OA) after surgery and radiation therapy. PATIENTS AND METHODS: In a prospective, nonrandomized, multicenter, phase II trial, patients were treated with 200 mg/m2 of TMZ on days 1 through 5 in 28-day cycles for 12 cycles. Patients with a recurrence after prior surgery and radiotherapy, and with measurable and enhancing disease on magnetic resonance imaging (MRI) were eligible for this study. Patients with large lesions and mass effect or with new clinical deficits were not eligible. Pathology and the MRI scans of all responding patients were centrally reviewed. RESULTS: Thirty-eight eligible patients were included. In three patients, pathology review did not confirm the presence of an OD or OA. TMZ was generally well tolerated. The most frequent side effects were hematologic; only one patient discontinued treatment for toxicity. In 20 (52.6%) of 38 patients (95% exact confidence interval, 35.8% to 69.0%), a complete (n = 10) or partial response to TMZ was observed. The median time to progression was 10.4 months for all patients and 13.2 months for responding patients. At 12 months from the start of treatment, 40% of patients were still free from progression. CONCLUSION: TMZ provides an excellent response rate with good tolerability in chemotherapy-naive patients with recurrent OD. A randomized phase III study comparing PCV with TMZ is warranted.

Adult↗
PubMed2003

Second-line chemotherapy with temozolomide in recurrent oligodendroglioma after PCV (procarbazine, lomustine and vincristine) chemotherapy: EORTC Brain Tumor Group phase II study 26972.

BACKGROUND: Oligodendroglial tumors are chemosensitive, with two-thirds of patients responding to PCV combination chemotherapy with procarbazine, lomustine (CCNU) and vincristine. Temozolomide (TMZ), a new alkylating and methylating agent has shown high response rates in recurrent anaplastic astrocytoma. We investigated this drug in recurrent oligodendroglial tumors (OD) and mixed oligoastrocytomas (OA) after prior PCV chemotherapy and radiation therapy. PATIENTS AND METHODS: In a prospective non-randomized multicenter phase II trial patients were treated with TMZ 150 mg/m(2) on days 1-5 in cycles of 28 days for 12 cycles. Eligible patients had a recurrence after prior PCV chemotherapy, with measurable and enhancing disease as shown by magnetic resonance imaging. Pathology and all responses were centrally reviewed. RESULTS: Thirty-two eligible patients were included. In four patients the pathology review did not confirm the presence of an OD or OA. Twelve of 24 patients [50%, 95% confidence interval (CI) 29% to 71%] evaluable for response to first-line PCV chemotherapy had responded to PCV. Temozolomide was in general well tolerated; the most frequent side-effects were hematological. One patient discontinued treatment due to toxicity. In seven of 28 patients (25%, 95% CI 11% to 45%) with histologically confirmed OD an objective response to TMZ was observed. Median time to progression for responding patients was 8.0 months. After 6 and 12 months from the start of treatment, 29% and 11% of patients, respectively, were still free from progression. CONCLUSIONS: TMZ may be regarded as the preferred second-line treatment in OD after failure of PCV chemotherapy. Further studies on TMZ in OD are indicated.

Adult↗
PubMed2003

A neuroimaging follow up study of a patient with juvenile central nervous system systemic lupus erythematosus.

BACKGROUND: The course of central nervous system systemic lupus erythematosus (CNS-SLE) is largely unknown. New imaging techniques are available to assist in monitoring the disease course. OBJECTIVE: To report a case of juvenile CNS-SLE, in which magnetic resonance imaging (MRI) was used to assess disease activity. CASE REPORT: A 10-year-old female patient with SLE presented with convulsions; MRI and computed tomography (CT) of the cerebrum disclosed abnormalities. Despite adequate treatment, two years later she had a generalised convulsion, and MRI showed new lesions. MR spectroscopy (MRS) indicated neuronal loss, inflammation, and metabolically compromised tissue; magnetisation transfer imaging (MTI) showed an increase in whole brain lesion load. After exclusion of a malignancy, CNS-SLE was the most likely diagnosis, and cyclophosphamide pulses were administered. Initially, multiple sclerosis (MS)-like lesions regressed, but despite maximal immunosuppressive drugs, new lesions formed and disappeared. When immunosuppressive drugs had been stopped for six months MRI showed improved lesions and MTI histograms. DISCUSSION: In this case report, the anatomical substrate, metabolic aspect, neuroimaging, and clinical course of MS-like lesions in a child with CNS-SLE are described. The way in which radiological techniques can support clinical decision making in this young patient with progressive CNS-SLE is illustrated.

Child↗
PubMed2002

Medical applications of Raman spectroscopy: from proof of principle to clinical implementation.

Raman spectroscopy has recently been applied ex vivo and in vivo to address various biomedical issues such as the early detection of cancers, monitoring of the effect of various agents on the skin, determination of atherosclerotic plaque composition, and rapid identification of pathogenic microorganisms. This leap in the number of applications and the number of groups active in this field has been facilitated by several technological advancements in lasers, CCD detectors, and fiber-optic probes. However, most of the studies are still at the proof of concept stage. We present a discussion on the status of the field today, as well as the problems and issues that still need to be resolved to bring this technology to hospital settings (i.e., the medical laboratory, surgical suites, or clinics). Taken from the viewpoint of clinicians and medical analysts, the potential of Raman spectroscopic techniques as new tools for biomedical applications is discussed and a path is proposed for the clinical implementation of these techniques.

Arteriosclerosis↗
PubMed2001

['Benign' meningioma].

Meningioma was diagnosed in four women, aged 40, 24, 41 and almost 75 years, respectively. The first of these patients was treated with surgery, the second and third patients underwent surgery followed by conventional radiotherapy because of a tumour residue or dural tail, and the last patient was treated with stereotactic radiosurgery. They recovered well and were followed by means of regular outpatient check-ups. Twenty percent of all primary brain tumours are meningiomas, over 90% of which are benign. Nevertheless, a large hospital-based population study showed a 5-year survival rate of only 70%. Microsurgery is usually the treatment of first choice. However, in about 25% of cases, excision is incomplete and tumour growth almost always continues. Further surgery influences prognosis unfavourably. New sophisticated radiation techniques help to control tumour progression in about 80-90% of cases. This success, however, may be associated with new cranial nerve deficits or panhypopituitarism. Prospective, comparative studies are not available.

Adult↗
PubMed2001

[Meningiomas: prognostic relevance of histopathologic and genetic markers].

The majority of meningiomas are histologically benign tumours. Location and invasion of tumour tissue in adjacent structures may hamper radical resections and give rise to recurrences. The rise in human life expectancy has prolonged the postoperative period and thus the risk of tumour recurrence has increased markedly. Infiltration in brain tissue and mitotic activity are important histologic features which negatively influence the disease-free duration of the postoperative period. Molecular studies of relevant genetic defects involved in meningioma are currently underway, but as yet these are of little clinical relevance.

Biomarkers, Tumor↗
PubMed2001

Temozolomide chemotherapy in recurrent oligodendroglioma.

The authors determined the tolerance, response rate, and duration of recurrent anaplastic oligodendroglioma in 30 patients to temozolomide given orally at 150 to 200 mg/m2 on days 1 through 5 in cycles of 28 days. Nine patients responded: 7 of 27 patients (26%) treated with temozolomide after prior PCV chemotherapy and 2 of 3 chemotherapy-naive patients (both complete response). Median time to progression in responding patients was 13 months. Temozolomide shows promise and has an acceptable safety profile in recurrent anaplastic oligodendroglial tumors. Patients not responding to PCV may respond to temozolomide.

Adult↗
PubMed2001

Spatial variability of genomic aberrations in a large glioblastoma resection specimen.

In the present study, the distribution of genetic aberrations in a glioblastoma resection specimen of unusually large size (9x8x2 cm) was investigated using comparative genomic hybridization (CGH). CGH was performed on 20 samples taken from the specimen, and the genetic aberrations found were compared with the regional histology. The samples were histopathologically graded according to WHO criteria, and a division in high- and low-grade areas and infiltration rims was made. In high-grade areas, low-grade areas as well as infiltration rims, gains on 10p11.2-pter (14/20), 11q12-q22 (6/20) and losses on 4q13-qter (9/20), 10q22-qter (8/20), 11p14-pter (5/20), 13q12-qter (7/20) were revealed. Gains on 1q21-32 (2/4) and losses on 7p21-pter (3/4) were exclusively found in the high-grade areas. In the low-grade tumor samples and in the infiltration rim, gains on 16p11.2-pter (6/16), 17p11.2-pter (6/16), 17q11.2-qter (5/16), 20q11.2-q13 (3/16) and deletions on 5q31-qter (4/16) were detected. Gains on 7q21-qter (8/11) and 8q11.2-qter (6/11), and loss of chromosome 9 (4/11) and the Y-chromosome (4/11) were found in the high-grade and low-grade samples, not in the infiltration rims. The finding of a set of identical chromosomal aberrations throughout the resection specimen, most of which have been previously reported in gliomas, confirms a mechanism of clonal tumor proliferation operative in gliomas. The previously unreported genetic alterations which were predominantly traced in the tumor rims, might reflect either selection for properties related to infiltrating behavior, or genomic instability of subclones. The findings illustrate the importance of searching for high-grade genetic aberrations in low-grade tumor samples taken from cases in which sampling error is suspected.

Brain Neoplasms↗
PubMed2001

Truncated NF2 proteins are not detected in meningiomas and schwannomas.

Neurofibromatosis type 2 is caused by mutations in the NF2 tumor suppressor gene. The NF2 gene encodes a 595-aminoacid protein, presumably functioning as a membrane-organizing element. Theoretically, the majority of mutations found in the NF2 gene should lead to a truncated protein product. Using immunoprecipitation with an antibody raised to N-terminal sequences of the NF2 protein, the authors sought to demonstrate the presence of truncated NF2 proteins in tumors. From 17 of 19 tumors (14 meningiomas and five schwannomas), 12 of which have previously been shown to harbor truncating NF2 mutations, wild-type NF2 protein was immunoprecipitated. From two tumors no protein was precipitated. Truncated NF2 proteins were not observed. The authors conclude that mutant NF2 proteins are unstable and undergo accelerated degradation.

Actins↗