Biomedical subjects

M Buchfelder

Publications and source records attributed to M Buchfelder.

At least 37 records · Page 2Linked to original sources

PubMed2004

Magnetic source imaging supports clinical decision making in glioma patients.

OBJECTIVE: This study addresses the potential utility of preoperative functional imaging with magnetoencephalography (MEG) for the selection of glioma patients who are likely to benefit from resective surgical treatment regarding postoperative morbidity. METHODS: One hundred and nineteen patients with gliomas adjacent to sensorimotor, visual and speech related brain areas were investigated preoperatively with a MAGNES II biomagnetometer. In each patient the pre-surgical evaluation was focussed on the visual, sensorimotor cortex and/or of the speech related brain areas. A grading system was then used according to the distance of the MEG activation sources to the nearest tumour border to determine the further treatment. The therapeutic options consisted in conservative treatment, stereotactic biopsy and/or a radiation and chemotherapy, substantial cytoreduction and the gross total removal of the lesion. RESULTS: From 119 investigated patients, 55 patients (46.2%) were not considered for surgery due to tumour invasion to functional cortex. Sixty four patients (53.8%) were chosen for resective surgery. In the surgical group only four patients (6.2%) suffered from neurological deterioration. CONCLUSIONS: Magnetic source imaging (MSI) proved to be a valuable help in the clinical decision making process of lesions adjacent to functional important brain areas. The relative high number of patients in whom MSI warns of the postoperative crippling sequelae may lead to a better selection of patients who benefit from resective surgery. This method may help to find the patients for whom conservative treatment seems to be more favourable concerning quality of life in the surviving time.

Adolescent↗

PubMed2004

Epilepsy surgery, resection volume and MSI localization in lesional frontal lobe epilepsy.

To verify whether interictal noninvasive information detected by magnetoencephalography (MEG) recordings can contribute to localize focal epileptic activity relevant for seizure generation in lesional frontal lobe epilepsy, magnetic source imaging (MSI) localizations of epileptic discharges were compared to the extent of neurosurgical resection and postoperative outcome. Preoperative MEG spike localizations were displayed in postoperative magnetic resonance imaging (MRI) scans to check whether dipole sites were located within the resection cavity. Moreover, MEG localizations were compared with results of prolonged video-EEG monitoring and, in three cases, with invasive EEG recordings. Our results in five cases with lesional frontal lobe epilepsy showed that good surgical outcome could be achieved in those patients where the majority of MEG spike localizations were located within the resected brain volume.

Adult↗

PubMed2004

Mutation analysis of leukemia inhibitory factor-receptor (LIF-R) in ACTH-secreting pituitary adenomas.

Numerous cytokines and particularly leukemia inhibitory factor (LIF) are involved in the differentiation, proliferation, and secretory function of ACTH-producing pituitary cells. LIF and its receptor LIF-R are abundantly expressed in normal pituitaries and in ACTH producing adenomas. The present study was performed to evaluate the possible role of LIF-R in the pathogenesis of ACTH-secreting pituitary adenomas. To test the hypothesis that a possible mutation of LIF-R might be involved in pathogenesis of Cushing's disease we analyzed ACTH-producing pituitary adenomas as well as inactive pituitary adenomas by RT-PCR and direct cycle sequencing. No mutations have been found in the adenomas investigated. We thus conclude that mutations in LIF-R are an unlikely cause for the development of Cushing's disease.

Adenoma↗

PubMed2004

Magnetoencephalography (MEG) predicts focal epileptogenicity in cavernomas.

OBJECTIVE: The aim of this study was to identify the irritative epileptic zone in patients with cavernomas by means of magnetoencephalography (MEG). METHOD: Among 82 patients operated for epilepsy, whose presurgical evaluation had included MEG, histological assessment of the tissue removed had confirmed cavernomas in eight. These eight patients had epilepsy since 18.6 (SD 12.7) years on average. The monitoring lasted about 2.1 (SD 1.3) hours and a median 20.9 (SD 14.3) spikes per hour were recorded. Spontaneous brain activity was recorded by means of a 74 channel dual unit MEG system (Magnes II, 4-D Neuroimaging) with simultaneous EEG recording (31 scalp electrodes). Spike analysis was performed using different source (moving dipole, current density reconstruction) and head models (spherical shells, BEM). Co-registration of neurophysiological and imaging data (MRI) was based upon anatomical landmarks. RESULTS: In 6/8 patients co-localisation from the cavernoma and epileptic zone was found. In two patients the focus was localised in the parieto-occipital lobe, in three patients in the frontal lobe and in three patients in the temporal lobe. In one case of temporal and one case of frontal lobe focus localisation there was no spatial relationship to the cavernoma. CONCLUSION: In cases of focal seizures due to a single cavernoma, MEG may precisely delineate the epileptogenic tissue bordering the lesion. In patients with multiple cavernomas or dual pathology, MSI may reveal the complexity of the case, and contribute to the decision about further invasive diagnostics and more sophisticated therapeutic measures. MEG is a promising method for prediction of the epileptic zone in cavernoma related epilepsies, and thus it can contribute to decision making about and planning of epilepsy surgery.

Adolescent↗

PubMed2003

Magnetic brain source imaging of focal epileptic activity: a synopsis of 455 cases.

Epilepsy surgery is based upon the minute assessment of brain tissue generating epileptic activity. A number of diagnostic methods are employed in the process of presurgical evaluation, supplying information on various morphological and functional aspects, ultimately integrated into the general result fundamental to the final treatment decision. Magnetic source imaging (MSI), combining structural (MRI) and functional (MEG) data, has been playing an increasingly important role among the tools of presurgical epilepsy evaluation. However, in spite of a considerable number of publications, the samples used have hardly exceeded 50 cases. Therefore, we present a synopsis of 455 epilepsy patients who underwent MSI investigations. Analysis of this substantial data revealed that the average sensitivity of MEG for specific epileptic activity was 70%. Among 131 patients who underwent surgical therapy in addition to antiepileptic drug medication, MSI identified the lobe to be treated in 89%, with results for extratemporal cases being even superior to those with temporal lobe surgery. Introducing a measure to quantify the contribution of MSI to the general result of presurgical evaluation that was applied to 104 patients, the results showed that MSI supplied additional information in 35% and information crucial to final decision making in 10%. Accuracy as well as contribution findings underlined MSI appropriateness even for extratemporal epilepsies, which otherwise frequently prove difficult with respect to focus localization.

Adolescent↗

PubMed2003

[Macroadenoma of the pituitary gland with moderate hyperprolactinaemia].

HISTORY AND CLINICAL FINDINGS: A 46-year-old woman was referred to the neurosurgery department for treatment of a macroadenoma of the pituitary. She had complained of recurrent galactorrhoea for 7 years; a hysterectomy was performed 4 years ago. The clinical investigation was unremarkable, except for a slight galactorrheoa on both sides. INVESTIGATIONS: The endocrinological work-up revealed a moderately elevated prolactin level of 3133 mU/l (147 ng/ml) with intact pituitary functions. She had no visual impairment and the MRI depicted a pituitary tumor with a maximal diameter of 1.9 cm and both intra- and suprasellar extension. DIAGNOSIS, TREATMENT AND CLINICAL COURSE: The diagnosis of a nonfunctioning macrodenoma with functional hyperprolactinemia was made and a selective transsphenoidal adenomectomy was performed. The primary histology showed a chromophobe adenoma. However, additional immunohistological investigations revealed distinct staining for prolactin. In the meantime, because of persistent galactorrhea and elevated prolactin levels, treatment with cabergolin 0.5 mg/week was started. This stopped galactorrhea and normalized the prolactin levels. A follow-up MRI after 3 months of treatment showed a significant shrinkage of the residual tumor. CONCLUSION: This case demonstrates that the differential diagnosis of macroprolactinoma with low secretory activity and functional hyperprolactinemia is very difficult preoperatively in individual cases. This is relevant because macroprolactinomas with low secretory activity can also be treated successfully with dopamine agonists. We therefore suggest a drug treatment trial with dopamine agonists in all macroadenoms with hyperprolactinemia, particularly in those with prolactin levels above 2000 mU/l (100 ng/ml).

Cabergoline↗

PubMed2003

Glioma surgery evaluated by intraoperative low-field magnetic resonance imaging.

OBJECTIVE: To give an overview on intraoperative magnetic resonance (MR) imaging in glioma surgery. MATERIAL AND METHODS: MR imaging was performed using a 0.2T scanner, located in a radiofrequency-shielded operating theatre. Two setups were used: surgery either in a neighbouring operating theatre, or directly at the 5G line. Additionally, in gliomas adjacent to eloquent brain areas microscope- or pointer-based neuronavigation with integrated functional data was applied. 106 gliomas were among the 330 patients investigated in the last 5 years. RESULTS: We did not observe complications attributable to intraoperative MR imaging. Image quality was sufficient to evaluate the extent of the tumour resection in the majority of cases. Intraoperative imaging revealed remaining tumour in 63%. In a total of 26% patients further tumour could be removed due to the results of intraoperative imaging, increasing the rate of complete tumour removal especially in the low-grade tumours. The additional use of functional neuronavigation prevented an increased morbidity. CONCLUSION: Intraoperative MR imaging offers the possibility of further tumour removal during the same surgical procedure in case of tumour remnants, increasing the rate of complete tumour removal. The effects of brain shift can be compensated for using intraoperative image data for updating.

Adolescent↗

PubMed2003

Image-guided removal of supratentorial cavernomas in critical brain areas: application of neuronavigation and intraoperative magnetic resonance imaging.

In a retrospective study the postoperative results of 26 patients operated on for supratentorial cavernous hemangiomas either deep-seated or near eloquent brain areas are summarized. An exact surgical approach to these lesions is essential to prevent neurological deterioration. Three different navigation systems were used and compared according to their clinical applicability. Complete removal of the lesion was obtained in all patients of this series. In six cases (23 %) functional data from magnetoencephalography or functional magnetic resonance imaging were integrated into the navigational setup. In 14 cases (54 %) intraoperative magnetic resonance imaging was performed. The follow-up time was 3 - 26 months (mean: 10 months). In the postoperative course one patient (3.8 %) developed a hemiparesis, another one developed quadrantopia. Nineteen patients presented with preoperative seizure history, 16 of these (84 %) had no further or rare seizures after surgery. The better results in seizure control were achieved in those patients with shorter duration of seizure history before surgery. The study indicates that the application of neuronavigation allows surgery on supratentorial cavernous hemangiomas in critical brain areas with low morbidity. The intraoperative visualization of eloquent cortex areas by integration of functional data allows a fast identification and exemption of eloquent brain areas, preventing neurological deterioration. Furthermore, the intraoperative MR resection control ensures a complete resection and illustrates the minimal invasive approach.

Adolescent↗

PubMed2003

Endocrine findings in patients with optico-hypothalamic gliomas.

OBJECTIVES: Optico-hypothalamic gliomas (OHG) are an important differential diagnosis in suprasellar tumors. Visual impairment and hydrocephalus are the most frequent findings at presentation. However, only limited data are available about endocrine disturbances in these lesions. PATIENTS AND METHODS: 38 consecutive patients (19 children) were studied retrospectively. Clinical assessment and endocrinological evaluation of pituitary and hypothalamic functions (combined pituitary stimulation test, ITT, CRH-GRH test) were performed before and after (1 week and 3 months) the neurosurgical procedure. RESULTS: Only three patients showed clinical features of endocrine deficiency initially. 16 children and 15 adults out of the 38 patients (31/38, 81.6 %) showed no abnormality in their hormone values when assessed with the combined pituitary stimulation test alone or using more sophisticated investigations such as ITT and CRH-GRH test (72.2 %). Patients with hypothalamic disturbances (8 out of 38, 21 %) had endocrine abnormalities more frequently than those without (57.1 % vs. 9 %, p < 0.05), as assessed by ITT and CRH-GRH-test. CONCLUSIONS: In contrast to other suprasellar tumors, endocrine deficiencies are surprisingly rare in optico-hypothalamic gliomas despite their large size, especially in the absence of hypothalamic disorders. This may be used as a criterion in the differential diagnosis of these lesions, in addition to the radiological findings.

Adolescent↗

PubMed2003

Frameless stereotactic brain biopsy procedures using the Stealth Station: indications, accuracy and results.

This study presents the results of 57 stereotactic brain biopsies using a frameless neuronavigation system, the Stealth Station. The supratentorial lesions had a mean diameter of 33 mm and a mean distance of 32 mm from the entry point at brain surface. In all cases the stereotactic procedure was planned in the preoperative 3-D magnetic resonance data set. In seven cases additional data for identification of eloquent brain areas was integrated from magnetoencephalography or functional magnetic resonance imaging. During surgery the samples were sent to neuropathological examination and the operation completed after the confirmation of pathological tissue. Using this method, in 56 cases a pathological tissue was obtained and a diagnostic yield of 98% was achieved. In two cases (3.5%) a new neurological deficit remained (hemiparesis and visual field deficit). The mean operation time was 92 minutes including examination of frozen sections. The results of our series demonstrate, that frameless stereotactic systems can also be reliably applied for biopsy of supratentorial lesions larger than 15 mm. Frameless stereotaxy in combination with intraoperative pathological confirmation is a safe and reliable method for stereotactic brain biopsy with a diagnostic yield comparable to frame-based stereotaxy.

Adolescent↗

PubMed2002

Serum procalcitonin monitoring for differential diagnosis of ventriculitis in adult intensive care patients.

The objective of our study was to assess the value of serum procalcitonin (PCT) monitoring in the differential diagnosis of ventriculitis in adult intensive care (ICU) patients. We analyzed 15 consecutive patients with ventriculitis in which a ventricular catheter had been inserted and contrasted these data with the observations in 10 patients with community-acquired bacterial meningitis. Cerebrospinal fluid (CSF) and blood samples were collected daily to assess serum PCT, C-reactive protein (CRP) and CSF leukocyte count. PCT levels were normal or slightly elevated in patients with ventriculitis with either positive or negative CSF bacterial culture but elevated in patients with bacterial meningitis. A PCT cut-off value of 1.0 ng/ml or more showed a specificity of 77% and a sensitivity of 68% for ventriculitis with positive CSF bacterial culture. Serum PCT levels reflected more accurately the time phases of disease during therapy. We conclude that the monitoring of serum PCT alone is not helpful for the differential diagnosis of ventriculitis, in contrast to that of bacterial meningitis. The value of PCT as an additional marker with which to assess the efficacy of therapy in ventriculitis is suggested, but requires further assessment.

Adolescent↗

PubMed2002

Expression of 5'-deiodinase enzymes in normal pituitaries and in various human pituitary adenomas.

OBJECTIVE: Local 5'-deiodination of l-thyroxine (T(4)) to active thyroid hormone 3,3',5-tri-iodothyronine (T(3)) catalyzed by the two 5'-deiodinase enzymes (D1 and D2) regulates various T(3)-dependent functions in the anterior pituitary and has been well studied in rodents. Only limited information about deiodinase expression and its cellular distribution in human anterior pituitaries is available. DESIGN: We examined 5'-deiodinase enzyme activities in pituitary adenomas (18 non-functioning, seven TSH-producing, one GH- and TSH-producing, five GH-producing, eight prolactin (PRL)-producing, two adenomas each from patients with Cushing's disease and Nelson's syndrome) and three normal anterior pituitaries. METHODS: Activities were measured as release of (125)I(-) from tyrosyl-ring labeled reverse T(3) with or without propylthiouracil, a potent inhibitor of D1 which does not influence D2 activities. RESULTS: Most of the adenomas and normal tissues expressed both isoenzymes, with D2 activity higher than D1. In a few tissues D1 activity was higher than D2 and some tissues did not express D1 activity at all. Highest activities of both enzymes were found in TSH- and PRL-producing adenomas but absolute activities and the D1/D2 ratio were variable in the same kind of tumor in different patients. CONCLUSION: The finding that all examined tissues expressed 5'-deiodinase activity, most of them expressing both isoenzymes, implies that both enzymes are still active in tumors and that local deiodination is important for the function and feedback regulation of human anterior pituitary.

Adenoma↗

PubMed2001

[Does resection of pituitary adenoma and radiotherapy cure the patient's symptoms?].

Today, pituitary adenomas are readily amenable to surgical treatment, and complication rates are low. With the exception of prolactin-producing adenomas, transsphenoidal or transcranial surgery is usually the treatment of choice. Indications for surgery are considered to be visual field deficits, functional disorders of the optomotor cranial nerves, or hypo-/hyperfunction of the pituitary. If treatment leads to normalization of the secretory dynamics, the long-term prognosis is favorable. If residual tumor or persistent overproduction of pituitary hormones is detected postoperatively, radiotherapy is applied. Endoscopic surgical procedures, intra-operative imaging and peri-operative determination of hormone levels enable the radicality of tumor removal to be further increased.

Acromegaly↗

PubMed2001

Spinal-thoracic dumbbell meningioma: a case report.

STUDY DESIGN: Total excision of a large dumbbell cervicothoracic intra- and extraspinal meningioma that had grown into the posterior mediastinum is described. This excision involved a two-step neurosurgical-thoracosurgical procedure within a short interval. OBJECTIVES: To document that the described laminectomy and thoracotomy techniques are adequate, safe, and effective for the treatment of this intra- and extraspinal meningioma lesion. SUMMARY OF BACKGROUND DATA: The management of intra- and extraspinal dumbbell tumors is based on anecdotal reports of mostly neurinomas, and thus remains a controversial issue. Even large series of spinal meningiomas lack adequate information on how best to treat large cervicothoracic meningiomas. METHODS: The authors have modified standard techniques used for resection of spinal and mediastinal tumors, respectively, adapting them for a large, invasive dumbbell meningioma in a 72-year-old lady. The patient initially underwent laminectomy and microsurgical excision of the intraspinal tumor portions encasing vascular structures. A week thereafter, a thoracotomy was performed, and the mediastinal tumor portions were removed completely. RESULTS: Restitution was remarkably good. The patient, who had been unable to walk on her own, regained some mobility. At this writing, she was able to walk considerable distances without support. There was no evidence of tumor recurrence during a follow-up interval of 3 years. CONCLUSIONS: The authors recommend a two-staged procedure for complete excision of a large spinal-thoracic meningioma. Even in elderly patients with major neurologic deficits, an impressive recovery can be achieved with such lesions.

Aged↗

PubMed2001

CDKN2A/p16 inactivation is related to pituitary adenoma type and size.

p16 (CDKN2A, MTS1, INK4A) status at genomic and protein levels was analysed and correlated with clinico-pathological features in 72 pituitary adenomas. Methylation of CpG islands of promoter/exon 1 sequences was found in most gonadotroph, lactotroph, plurihormonal, and null cell adenomas (36 of 44, 82%), but it was rare in somatotroph (1 of 13 cases, 8%) and corticotroph adenomas (1 of 15 cases, 7%). Homozygous CDKN2A deletion was restricted to rare somatotroph (15%) and corticotroph adenomas (13%). Immunohistochemical p16 protein expression was observed in the normal adenohypophysis, whereas it was absent in 60 of 72 (83%) tumours and reduced in another ten (14%) tumours. Staining for p16 was only seen in 5 of 15 (33%) corticotroph, 3 of 13 (23%) somatotroph, 3 of 5 (60%) plurihormonal, and 1 of 19 (5%) null cell adenomas. p16 immunonegativity without CDKN2A methylation or deletion occurred in 22 tumours, including most somatotroph and corticotroph adenomas (15 of 28, 54%). Both CDKN2A alterations and p16 negativity were related to larger tumour size. Patients with p16-negative tumours were older than patients with p16-positive tumours. These data suggest that p16 down-regulation is common in all adenoma types. The mechanisms of p16 down-regulation probably involve CDKN2A methylation in most types, but remain to be determined in somatotroph and corticotroph adenomas. These findings also suggest that p16 down-regulation is usually not an initial event, but is acquired during adenoma progression.

Adenoma↗

PubMed2001

[Diagnostic imaging in refractory temporal lobe epilepsy. A comparison of MR volumetry and multivoxel-MR-spectroscopy for assessment of postoperative prognosis].

While the importance of magnetic resonance (MR) spectroscopy, volumetry, and T2-relaxometry for preoperative localization has already been verified, the question arises as to what extent the individual techniques are useful for assessing postoperative prognosis with respect to seizures and neuropsychological outcome. In a prospective comparative study, 26 patients were examined preoperatively with a 1.5 T whole-body scanner. The MR spectroscopy was taken by high resolution 1 H proton spectroscopy, the volumetry with MP rage technique. The postoperative outcome was laid down using Engel's classification. Our results show that the metabolic changes can be divided into three groups using MR spectroscopy: unilateral, slightly bilateral, and severely bilateral to contralateral. In case of bilateral changes, the severity of metabolic changes in the nonoperated, contralateral side was decisive for postoperative outcome. The results from volumetry did not correlate with postoperative outcome.

Adult↗

PubMed2001

Current management of prolactinomas.

Prolactinomas constitute the largest group of pituitary adenomas in autopsy series. However, their relative incidence in recent surgical series is much less impressive since medical treatment with dopamine agonists is routinely employed, which in many cases leads to tumor shrinkage and normalization of prolactin levels. The clinical symptoms of hyperprolactinemia are menstrual dysfunction and galactorrhea in women and loss of libido and potency in men. Prolactinomas may present also as space occupying sellar mass lesions impinging on the adjacent structures like the pituitary gland, cavernous sinus and optic nerves. The standard primary treatment is medical by dopamine agonists. Prolactinomas are the prototype of tumors, the growth of which can be reliably and safely inhibited by specific drugs other than cytostatic chemotherapy. These unfortunately have side effects, like orthostatic hypotension, nausea and vomiting. The effects induced by dopamine agonists are suppressive but not tumoricidal. Thus, the therapeutic effect is only maintained as long as the drug is administered. Consequently. in most cases, treatment has to be continued life-long with a few exceptions, in whom normoprolactinemia persists even after discontinuation of dopamine agonists. Main indications of surgery in prolactinomas are intolerance of the medication, and tumors not responding to dopamine agonists. Occasionally, these may ultimately require radiation therapy. Remission rates in large series of surgically treated prolactinomas vary between 54% and 86%. In our consecutive series of 540 surgically treated prolactinomas, the normalization rate after transsphenoidal surgery basically depended on the preoperative prolactin levels, tumor size and extension. The remission rate of 82% in microprolactinomas with initial prolactin levels <200 ng/ml would even in small adenomas make one consider surgical treatment as an interesting alternative to long-term medical treatment.

Animals↗

PubMed2001

Disease latency in Creutzfeldt-Jakob disease via dural grafting: a case report.

The case of a 57-year old man is reported who had been operated upon for cerebellar angioblastoma more than 19 years previously. Having received a lyophilized dural patch he developed Creutzfeldt-Jakob disease of which he died 19 months later. This is the longest latency with dura-associated Creutzfeldt-Jakob disease reported so far.

Cerebellar Neoplasms↗