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Biomedical subjects

K Münkel

Publications and source records attributed to K Münkel.

7 recordsLinked to original sources
PubMed2002

High frequency stimulation of the basal ganglia for the treatment of movement disorders: current status and clinical results.

High frequency stimulation of the basal ganglia has gained much interest during the last years. Based on the reevaluation of the results of functional neurosurgery for movement disorders from Leksell's group, pallidotomy as lesional procedure was the first functional operation that underwent a renaissance for the treatment of movement disorders. The work by Benabid and Siegfried who carried out thalamic high frequency stimulation to suppress tremor, the knowledge about deep brain stimulation (DBS) for the treatment of chronic pain as well as better understanding in basal ganglia physiology and the development of reliable stimulation hardware led to an increasing number of centers worldwide who currently apply high frequency DBS for different movement disorders. In the present review the current status of DBS for movement disorders is presented and the results with high frequency stimulation targeted at different brain areas are summarized.

Animals↗
PubMed2001

Restricted diffusion within ring enhancement is not pathognomonic for brain abscess.

BACKGROUND AND PURPOSE: Recent experience suggests that diffusion-weighted MR imaging may be decisive in the differential diagnosis of ring-enhancing cerebral lesions. Whether restricted diffusion within a ring-enhancing cerebral mass lesion is pathognomonic for abscess was studied. METHODS: Seventeen patients with ring-enhancing cerebral lesions (three abscesses, six glioblastomas, eight metastases) on conventional contrast-enhanced T1-weighted images were examined with echo-planar diffusion-weighted MR imaging. Apparent diffusion coefficient (ADC) maps and the ADCs were calculated for all lesions. Lesions with signs of intralesional hemorrhage on unenhanced T1-weighted images were excluded. RESULTS: The central portion of all six glioblastomas and seven of eight metastases showed unrestricted diffusion, whereas two of three abscesses showed restricted diffusion (low ADC values) in their cavity. However, restricted diffusion also was found in one metastasis, and one abscess within a postoperative cavity showed unrestricted diffusion within a larger nondependent portion. CONCLUSION: In patients with ring-enhancing cerebral mass lesions, restricted diffusion might be characteristic but is not pathognomonic for abscess, as low ADC values also may be found in brain metastases.

Brain Abscess↗
PubMed2000

Magnetisation transfer ratio is low in normal-appearing cerebral white matter in patients with normal pressure hydrocephalus.

We measured the magnetisation transfer ratios (MTR) of normal-appearing rostral (PR) and caudal (PC) periventricular white matter, the genu (CG) and the splenium (CS) of the corpus callosum and the thalamus (TH) in 12 patients with normal-pressure hydrocephalus (NPH) and compared them with 16 healthy control subjects. We found a significantly lower MTR in the NPH group than in the normal group for PR, PC, CG, and CS but not for TH. MT measurements give additional information which cannot be gained by conventional MRI, suggesting that NPH is associated with diffuse white matter damage, even in normal-appearing cerebral white matter.

Adult↗
PubMed2000

Aberrant p21 regulation in radioresistant primary glioblastoma multiforme cells bearing wild-type p53.

OBJECT: A clearer understanding of the cellular mechanisms involved in the response to ionizing radiation is pivotal to the development of new therapeutic strategies for glioblastoma multiforme (GBM). To gain insight into dynamic functional aspects of cell cycle regulation and the control of apoptosis in GBMs, the authors investigated the molecular changes induced by ionizing radiation in genetically characterized primary GBMs in vitro compared with secondary GBMs, Grades II and III gliomas, and three GBM cell lines. METHODS: Irradiation of primary GBMs bearing wild-type (wt) p53 invariably fails to invoke the G, checkpoint and apoptosis in vitro. In approximately half of these primary GBMs a defect lies at or above the level of p53 because transcriptional activation of p21 and bax after irradiation does not occur. The failure of a p21 response to irradiation is invariably accompanied by overexpression of p21 mRNA under nonirradiated conditions. In all remaining primary GBMs transcriptional activation of p21 after irradiation does occur, suggesting that a defect downstream from p21 prevents G, arrest. CONCLUSIONS: These results show that the G, checkpoint and the p53 pathway are dysfunctional in primary GBMs in vitro, despite the presence of an intact p53 gene. The data also suggest that primary GBMs may be divided into two categories on the basis of their p21 response to irradiation.

Adult↗
PubMed1999

[Late myelopathy after chemonucleolysis. Case report and review of the literature].

Chemonucleolysis is a debated therapeutic method for herniated lumbar disc. We report a patient who suffered a sequence of characteristic sequels cumulating in late-onset myelopathy with persistent spastic paraplegia, sensory loss below T8 and bladder incontinence. Complications of chemonucleolysis are less frequent as compared to herniated disc surgery, but may cause severe impediment. Serious complications are anaphylactic shock, intracranial or spinal hemorrhage and transverse myelitis. This has to be taken into account for indication and patient information.

Chymopapain↗
PubMedDate not supplied

Magnetization transfer measurements in normal-appearing cerebral white matter in patients with chronic obstructive hydrocephalus.

PURPOSE: The purpose of this work was to assess the presence of subtle changes in normal-appearing white matter on T2-weighted MR images in patients with chronic obstructive hydrocephalus using magnetization transfer (MT) measurements. METHOD: In 12 patients with chronic obstructive hydrocephalus, MT ratios (MTRs) of normal-appearing rostral (PR) and caudal (PC) periventricular white matter, of the genu (CG) and the splenium (CS) of the corpus callosum, and of the thalamus (TH) were measured and compared with those of 16 healthy control subjects. RESULTS: We found a significantly lower MTR in chronic obstructive hydrocephalus than in the normal group for PR, PC, CG, and CS but not for TH. CONCLUSION: Our study shows that MT measurements give additional information that cannot be gained by conventional SE MRI, suggesting that chronic obstructive hydrocephalus is associated with diffuse white matter damage that also affects normal-appearing cerebral white matter.

Adult↗