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J C Kiwit

Publications and source records attributed to J C Kiwit.

At least 19 recordsLinked to original sources
PubMed2004

Embolization of indirect carotid-cavernous sinus fistulas using the superior ophthalmic vein approach.

OBJECTIVES: In indirect carotid-cavernous sinus fistulas (CCF), abnormal connections exist between tiny dural branches of the external and/or internal carotid system and the cavernous sinus. Usually this kind of fistula occurs spontaneously and is characterized by a low shunt volume. Alternative vascular approaches for embolization are required when standard interventional neuroradiological access via arterial or transfemoral venous routes is not feasible. PATIENTS AND METHODS: Two symptomatic patients with indirect CCFs are described. Transarterial and transfemoral venous approach was unsuccessful or resulted in incomplete occlusion of the CCF. Therefore, the superior ophthalmic vein (SOV) was surgically exposed and retrograde catheterized to allow the delivery of platinum coils to the fistula point via a microcatheter. RESULTS: Complete fistula obliteration was accompanied by recovery of the clinical symptoms. CONCLUSION: The surgical SOV approach might be sufficient when standard neuroradiological procedures do not succeed. The technique is safe and effective when performed by an interdisciplinary team.

Carotid Artery, Internal↗
PubMed2001

GABA(A)-receptor expression in glioma cells is triggered by contact with neuronal cells.

The expression of functional GABA(A)-receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABA(A)-receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABA(A)-receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABA(A) receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and microglia. Glioma cells expressed functional GABA(A) receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABA(A)-receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain.

Action Potentials↗
PubMed2000

Focal cortical dysplasia of the temporal lobe with late-onset partial epilepsy: serial quantitative MRI.

We describe serial studies of focal cortical dysplasia causing temporal lobe seizures and progressive aphasia in a 54-year-old woman. Initially, MRI volumetry of the temporal lobes showed significant left cortical thickening corresponding to an elevated amino-acid uptake in the left temporoparietal and inferior frontal cortex on SPECT using 3-[123I]iodo-alpha-methyl-L-tyrosine (IMT). After 1 year there was severe shrinkage of the left temporal lobe, possibly the result of recurrent complex partial seizures.

Aphasia↗
PubMed1998

Precentral glioma location determines the displacement of cortical hand representation.

OBJECTIVE: Low-grade brain tumors may remain asymptomatic in contrast to malignant gliomas. The mechanisms underlying the preservation of cerebral function in such gliomas are not well understood. METHODS: We used positron emission tomography and transcranial magnetic stimulation for presurgical monitoring of motor hand function in six patients with gliomas of the precentral gyrus. All patients were able to perform finger movements of the contralesional hand. RESULTS: Movement-related increases of the regional cerebral blood flow occurred only outside the tumor in surrounding brain tissue. Compared with the contralateral side, these activations were shifted by 20 +/- 13 mm (standard deviation) within the dorsoventral dimension of the precentral gyrus. This shift of cortical hand representation could not be explained by the deformation of the central sulcus as determined from the spatially aligned magnetic resonance images but was closely related to the location of the maximal tumor growth. Dorsal tumor growth resulted in ventral displacement of motor hand representation, leaving the motor cortical output system unaffected, whereas ventral tumor growth leading to dorsal displacement of motor hand representation compromised the motor cortical output, as evident from transcranial magnetic stimulation. In two patients, additional activation of the supplementary motor area was present. CONCLUSION: Our data provide evidence for the reorganization of the human motor cortex to allow for preserved hand function in Grade II astrocytomas.

Adult↗
PubMed1998

Comparison of iodotyrosines and methionine uptake in a rat glioma model.

UNLABELLED: This study compares brain tumor imaging with 3-[123I]iodo-alpha-methyl-L-tyrosine (IMT) and 3-[123I/125I]iodo-O-methyl-alpha-methyl-L-tyrosine (OMIMT) to that with [methyl-3H]-L-methionine (Met) in a rat glioma model by double-tracer autoradiography. METHODS: Cells of the glioma clone F-98 were implanted stereotactically into the right basal ganglia of 22 Fischer 344 rats. After 8 days of tumor growth, the animals simultaneously were injected with a mixture of either 123I-IMT and 3H-Met (n=5), 123I-OMIMT and 3H-Met (n=8) or 123I-IMT and 125I-OMIMT (n=9). The animals were killed 15 min after the tracer injection and cryosections of the tumor-bearing brain area were exposed to phosphor-imaging plates both immediately and after the decay of 123I. Tumor-to-brain ratios (T/B) and intratumoral distribution of the different tracers and of the cresyl violet staining of the tissue were compared. RESULTS: There was a significant correlation of the T/B ratios between all tracers (IMT versus Met: r=0.97, n=5, p < 0.01; OMIMT versus Met: r=0.94, n=8, p < 0.001; OMIMT versus IMT: r=0.95, n=9, p < 0.001). Intratumoral tracer distribution was similar for all tracers and the extent of tumor labeling was identical to that of the histological tumor extent. Mean values of the T/B ratios, however, were lower for IMT (2.81+/-0.78, n=14, mean+/-s.d., p < 0.01 compared with Met) and for OMIMT (2.03+/-0.57, n=17, p < 0.01 compared with Met) than for Met (3.86+/-1.12, n=13). CONCLUSION: This study confirms that tumor imaging with IMT is similar to that of Met but T/B ratios of IMT are lower. OMIMT intratumoral tracer distribution and tumor size are similar to Met and IMT, but the T/B contrast is rather low and makes this amino acid less suitable for clinical application.

Animals↗
PubMed1997

Whole-body kinetics and dosimetry of L-3--123I-iodo-alpha-methyltyrosine.

The synthetic amino acid L-3--123I-iodo-alpha-methyltyrosine (IMT) is currently under clinical evaluation as a single-photon emission tomography (SPET) tracer of amino acid uptake in brain tumours. So far, dosimetric data in respect of IMT are not available. Therefore we investigated the whole-body distribution of IMT in six patients with cerebral gliomas and the radiation doses were estimated. Whole-body scans were acquired at 1.5, 3 and 5 h after i.v. injection of 370-550 MBq IMT. The bladder was voided prior to each scan and the radioactivity excreted in the urine was measured. Based on the MIRD-11 method and the updated MIRDOSE3, the mean absorbed doses for various organs and the effective dose were calculated from geometric means of the anterior and posterior whole-body scans using seven source organs and the residence time. IMT was predominantly excreted by the kidneys (52.8%+/-11.5% at 1.5 h p.i., 63.0%+/-15.7% at 3 h p.i. and 74.6%+/-9.8% at 5 h p.i.). No organ system other than the urinary tract showed significant retention of the tracer. Early whole-body scans revealed slightly increased tracer uptake in the liver and in the bowel. Highest absorbed doses were found for the urinary bladder wall (0.047 mGy/MBq), the kidneys (0.010 mGy/MBq), the lower large intestinal wall (0.011 mGy/MBq) and the upper large intestinal wall (0.008 mGy/MBq). The effective dose according to ICRP 60 was estimated to be 0.0073 mSv/MBq for adults. This leads to an effective dose of 3.65 mSv in a typical brain SPET study using 500 MBq IMT. The MIRDOSE3 scheme yielded similar results. Thus, in spite of the relatively high tracer dose required for optimal brain scanning, radiation exposure in SPET studies with IMT is in the normal range of routine nuclear medicine investigations.

Adult↗
PubMed1997

3-[123I]iodo-alpha-methyltyrosine and [methyl-11C]-L-methionine uptake in cerebral gliomas: a comparative study using SPECT and PET.

UNLABELLED: This study compares the uptake of the nonmetabolizable amino acid analog 3-[123I]iodo-alpha-methyltyrosine (IMT) and of [methyl-11C]-L-methionine (MET) in cerebral gliomas. METHODS: In 14 patients with cerebral gliomas, IMT uptake was measured using SPECT (10 dynamic, 4 static SPECT acquisitions) and, on the same day, MET uptake by dynamic PET. The IMT and MET data were compared with respect to tracer kinetics, tumor to brain ratios (T/B) and tumor size after converting the resolution of the PET scans to that of the SPECT scans (14 mm FWHM). RESULTS: All gliomas showed increased uptake of both tracers in relation to normal brain tissue. Visual comparison of the scans yielded no differences in tumor size and shape with both methods. IMT showed a maximal tracer uptake in brain and in tumors at about 15 min postinjection which was followed by a washout of 45.0% +/- 13.5% in gliomas (mean +/- s.d., p < 0.001, n = 10) and 35.3% +/- 5.4% in normal brain (p < 0.001, n = 10) at 60 min postinjection. MET concentration in tumor tissue or brain tissue between 15 and 60 min remained constant. T/B ratios of IMT SPECT and MET PET showed a significant correlation at 15 min postinjection (r = 0.69, n = 10, p = 0.03), a low correlation for the mean values of the scans from 15-60 min postinjection (r = 0.54, n = 14, p = 0.05) and no correlation at 60 min postinjection (r = 0.09, n = 10, n.s.). CONCLUSION: IMT and MET uptake in gliomas is similar in the early, transport dominated phase. There are some differences in tumor to brain ratios between both tracers within the first hour postinjection that are mainly caused by variable washout of IMT. Imaging of tumor extent with IMT SPECT is comparable to MET PET. Thus, amino acid SPECT using IMT is a promising tool to evaluate the biological activity and intracerebral infiltration of gliomas.

Adult↗
PubMed1996

Survival in malignant glioma: analysis of prognostic factors with special regard to cytoreductive surgery.

Although the question of optimal treatment for malignant gliomas has been addressed in many retrospective papers, no clear answer has been found to what extent surgical removal of tumor tissue should be performed. We conducted a retrospective analysis in 274 unselected patients, admitted to our institution with the diagnosis of malignant supratentorial glioma. Median survival time after surgery was analyzed with respect to the following defining variables: Age, pre- and postoperative Karnofsky Performance Scale (KPS), tumor location, histology, sex, pre- and postoperative tumor volume and volumetrically measured extent of resection. All these defining variables with exception of sex and preoperative tumor volume were of significant influence on the median survival time of glioma patients (Kolmogoroff-Smirnoff test, Log-Rank test, Breslow test and Tarone-Ware test p < 0,05). To exclude covariant influences of these variables on patients survival and to answer the question of the best surgical option, a matched pair analysis between 40 patients undergoing stereotactic biopsy and 40 patients undergoing cytoreductive surgery was performed. Median survival time (MST) in the biopsy group was 184 days whereas the cytoreductive surgery group had a MST of 292 days (p < 0,05). In addition median postoperative KPS at the point of discharge in patients with tumor resection was slightly better (KPS 58%) in comparison with the biopsy group (KPS 53%) but not on a significant level. It is concluded from these data that patients harbouring malignant gliomas clearly benefit from cytoreductive surgery compared with stereotactic biopsy regarding life expectancy and mildly regarding life quality.

Adolescent↗
PubMed1995

Stiff-person syndrome with anti-glutamic acid decarboxylase autoantibodies: complete remission of symptoms after intrathecal baclofen administration.

A female patient, aged 61 years, who developed a severe immobilizing stiff-person syndrome in conjunction with insulin-dependent diabetes mellitus, is described. In addition to the typical clinical symptoms, diagnosis was proven by the presence of autoantibodies against glutamic acid decarboxylase in serum and cerebrospinal fluid. Symptomatic treatment with continuous intrathecal application of baclofen administered by a subcutaneous pump resulted in rapid clinical improvement so that the patient became ambulatory. Intermittent withdrawal from intrathecal baclofen therapy led to complete remanifestation of stiff-person syndrome within 18 h; after re-introduction of intrathecal therapy stiffness disappeared completely within 48 h. The clinical course has been stable now for over 24 months and stiffness has completely disappeared. The effect of baclofen in this patient is discussed in the light of the suggested pathophysiological mechanisms in stiff-person syndromes.

Autoantibodies↗
PubMed1995

[Possibilities of the use of MR tomography-based cerebral blood volume maps in the diagnosis of brain tumors].

PURPOSE: Today contrast enhanced MR imaging is a reliable method for detecting mostly distinguishing between different histological types of tumours. In this study we use a MR-based method to measure the regional cerebral blood volume (rCBV). Using this technique we try to judge the grading and vitality of the tumours. METHODS: 26 patients with various types of brain tumours were examined. To calculate rCBV-maps of one slice, low-dosed Gd-DTPA was injected as a bolus. Using the relaxation effect the obtained signal intensity-time curves were converted pixel-wise into rCBV images. For the tumours rCBV-ratios were calculated relative to the corresponding area in the contralateral hemisphere. RESULTS: In the investigated group all tumours were detected on the basis of a raised rCBV-ratio. Since only vital parts of the tumour are perfused, the rCBV maps may be used to determine the place of biopsy. CONCLUSIONS: The differential diagnosis of all histological tumour types was not possible on the basis of rCBV values. Distinction between low grade and high grade gliomas was also not significant. However, a low grade glioma can be excluded if the morphological images definitely indicate an astrocytoma and if the rCBV-ratio was higher than 2.

Adult↗
PubMed1994

Reversal of chemoresistance in malignant gliomas by calcium antagonists: correlation with the expression of multidrug-resistant p-glycoprotein.

Resistance to multiple drugs is often observed in malignant gliomas. The authors used a microtiter tetrazolium test to analyze primary in vitro chemoresistance and chemosensitivity of 15 early cultures of human malignant glioma exposed to 50 micrograms/ml (1,4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosoure a (ACNU), 50 micrograms/ml cisplatin, 1 microgram/ml vincristine, or combinations of these chemotherapeutic agents. Primary chemoresistance was observed in 87% of tumors for ACNU, in 87% for cisplatin, and in 83% for vincristine. All tumors were examined for expression of multidrug-resistant p-glycoprotein, a transport protein of 170,000 D, by means of immunohistochemical staining with the JSB-1 antibody on paraffinized tumor sections. Eight of 15 specimens (53%) showed positive staining for the monoclonal antibody. Primary chemoresistance was overcome by addition of the calcium antagonists verapamil or nimodipine to the cultures if the original tumor expressed p-glycoprotein (p < 0.01 for verapamil, p < 0.05 for nimodipine). In tumors not expressing p-glycoprotein, addition of calcium antagonists to the cell cultures did not influence primary chemoresistance. It is concluded from these data that addition of calcium antagonists to the adjuvant chemotherapy of malignant gliomas might overcome primary chemoresistance in tumors expressing the multidrug-resistant phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Stereotactic laser therapy in cerebral gliomas.

The 1.06 micron Nd:YAG laser and a new fiberoptic delivery system, the Interstitial Thermo-Therapy (ITT) laser fibre, allows stereotactic interstitial irradiation of cerebral tumours. In experimental rat brain studies we found typical laser-tissue effects with a central necrosis and a sharply demarcated oedema towards the normal brain. The size of the lesion depended on the energy and exposure time applied. In a pilot series we treated 5 patients with cerebral gliomas WHO grade II-III in functionally important regions and monitored the therapeutic effects by MR imaging and PET scan. Early post-operative results showed irreversible necrotic changes in the tumour centre and reversible oedematous changes at the tumour margin. Long-term results will show if stereotactic interstitial laser therapy is a useful supplementary method in the treatment of malignant cerebral tumours.

Animals↗
PubMed1991

Effects of recombinant human tumor necrosis factor on rodent gliomas and normal brain.

In a study examining the possible therapeutic effects of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) on malignant gliomas without expression of tumor necrosis factor (TNF)-receptors, RG-2 glioma cells were tested in vitro as well as in a rat experimental glioma model. A growth inhibition assay revealed no inhibiting effect in vitro up to a concentration of 20 micrograms/ml rHuTNF-alpha. Receptor-binding studies showed that RG-2 cells did not present specific receptors for rHuTNF-alpha. The pharmacokinetics of rHuTNF-alpha after intravenous injection were studied with respect to serum, tissue, and brain tumor concentrations and showed increased glioma concentrations of (mean +/- standard error of the mean) 0.47 +/- 0.18 ng TNF/mg brain compared to 0.15 +/- 0.05 ng TNF/mg brain in the normal contralateral hemisphere. No therapeutic effect on solid RG-2 gliomas could be observed after stereotactic injection of 7.3 micrograms rHuTNF/10 microliter buffer solution into the tumor in 10 animals. Immunohistochemical studies after stereotactic injection of rHuTNF-alpha showed total disappearance of the substance after 24 hours without internalization into tumor cells. Stereotactic injection of 7.3 micrograms rHuTNF 10 microliters into normal brain resulted in marked inflammatory response around the injection track, including microvascular thrombosis. These results demonstrate that rHuTNF has neither direct nor indirect cytotoxic activity on RG-2 glioma cells. Furthermore, before clinical use of rHuTNF-alpha in malignant gliomas, the authors suggest that receptor studies be done in each patient. In receptor-positive patients undergoing treatment with rHuTNF-alpha, precautions should be taken to prevent local encephalitic reactions.

Animals↗
PubMed1990

Metastatic adenocarcinoma in cerebral astrocytoma: clinicopathological and immunohistochemical study with review of the literature.

Metastatic spreading of carcinoma into a pre-existing cerebral glioma is extremely rare and only a few well-documented cases have been reported in the literature. Here we report a 53-year-old man who at the age 49 was first operated on for a frontal astrocytoma (WHO-grade II). This tumour was completely resected and no post-operative radio- or chemotherapy was applied. About five years later the patient presented again with a large partially cystic space-occupying lesion at the same site, which pre-operatively appeared as a recurrence of the astrocytoma. Histologically, however, this tumour proved to be a metastatic adenocarcinoma into a recurrent astrocytoma. Further clinical examinations revealed a bronchial carcinoma as the primary lesion responsible for this unusual metastatis. The clinical and neuropathological findings of this interesting case including immunohistochemistry are presented and discussed.

Adenocarcinoma↗
PubMed1989

Adjuvant intraarterial chemotherapy with nimustine in the management of World Health Organization Grade IV gliomas of the brain. Experience at the Department of Neurosurgery of Düsseldorf University.

A protocol with postoperative adjuvant intraarterial (ia) chemotherapy using nimustine (ACNU) was followed at the University of Düsseldorf (Federal Republic of Germany) after histologic confirmation of malignant glioma of the brain. The first iaACNU procedure was performed within 10 days of surgery, and immediately before postoperative irradiation. After radiotherapy further iaACNU courses were given. The study population consisted of 35 primarily treated malignant gliomas World Health Organization (WHO) Grade IV, i.e., glioblastomas (NIV). Of these tumors 11 showed early progressive disease (PD) (NIV primPD), whereas 24 had stable or responsive disease (NIV SD&RD). Seven patients with recurrent malignant gliomas WHO Grade IV (NIV recurrent) were also treated plus six patients with malignant gliomas WHO Grade III (NIII). Experience with 50 treated patients resulted from this study. The median survival time (MST) for the group NIV was 14.2 months; 41.0% of patients were long-term survivors. The MST for the group NIV primPD was 7.8 months; 9.1% of patients were long-term survivors. For the group NIV SD&RD a MST of 18.3 months and 66.7% of long-term survivors were determined. Patients with recurrent tumors on this treatment protocol had an additional MST of 6.1 months. The total MST after first surgery was 16.2 months. The incidence of complications was low. Systemic complications were infrequent or rare. Retinal disturbances were seen in two patients; leukoencephalopathy was not seen in our patients. In 10% of patients cerebral complications were found, which were irreversible in 2% of patients. Complications could not be assigned unequivocally to the nitrosourea. These results compare favorably with what is reported in the literature, demonstrate the potential value of iaACNU in the treatment of malignant gliomas WHO Grade IV, and should encourage the initiation of a randomized clinical trial of adjuvant iaACNU in the therapy of these tumors. The authors propose iaACNU as a valuable approach in the management of primarily diagnosed malignant gliomas WHO Grade IV, but cannot recommend the delay of iaACNU until the recurrence of a brain tumor.

Adult↗