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Biomedical subjects

U Missler

Publications and source records attributed to U Missler.

At least 19 recordsLinked to original sources
PubMed2004

Evaluation of CSF glial fibrillary acidic protein (GFAP) as a putative marker for HIV-associated dementia.

BACKGROUND: The involvement of the central nervous system (CNS) is a prominent feature of infection with human immunodeficiency virus type-1 (HIV-1). One of the neuropathological hallmarks of HIV-1-associated dementia (HAD) is the proliferation of astrocytes (astrogliosis). The major structural protein of astrocytes is glial fibrillary acidic protein (GFAP) and its increased expression has been reported in disorders characterized by astrogliosis. PATIENTS AND METHODS: In order to determine whether CSF GFAP may be a putative marker for HAD, we measured CSF GFAP levels of HIV-infected patients with (n = 11) and without (n = 21) HAD, and, additionally, of HIV-infected patients with opportunistic CNS diseases (n = 13) and HIV negative control patients (n = 20) using an immuno flourescent sandwich immunoassay. RESULTS: CSF GFAP levels and the frequency of increased GFAP levels did not significantly differ between the three groups of HIV-infected patients. CONCLUSION: Our data suggest that CSF GFAP is not a sensitive laboratory marker for HAD.

AIDS Dementia Complex↗
PubMed2004

Cerebral and extracerebral release of protein S100B in cardiac surgical patients.

Although several clinical studies have shown that increased serum concentrations of protein S100B predict ischaemic brain damage after cardiac surgery, S100B may also be released from the heart or other injured tissue. We therefore investigated the correlation between serum S100B levels and those of the specific cardiac marker troponin I in order to assess the cerebral vs. extracerebral origin of S100B. In 64 cardiac surgical patients, serial blood samples were drawn for the measurement of S100B and troponin I before surgery and for seven days after surgery. Neurological function was assessed before with the National Institutes of Health Stroke Scale and the Folstein Mini Mental Test. The data show that a sustained increase in serum S100B levels is associated with neurological dysfunction, as witnessed by a positive correlation between S100B values and the results of the neuropsychological tests. In contrast, the early postoperative increased levels of protein S100B derive from cardiac tissue, as shown by the positive correlation between S100B and cardiac troponin I levels.

Adult↗
PubMed2004

Contralateral cerebral blood flow velocity changes after intracarotid amobarbital injection.

BACKGROUND AND PURPOSE: The intracarotid amobarbital procedure (IAP) leads to a prompt decrease in ipsilateral middle cerebral artery (MCA) mean blood flow velocity (MFV). Little is known about contralateral MFV changes. METHODS: The authors investigated bilateral MCA MFV using transcranial Doppler sonography (TCD) in 8 patients with epilepsy undergoing IAP. Measurements were excluded from analysis if angiography revealed any signs of interhemispheric cross-flow. RESULTS: With in 64 seconds after amobarbital injection, ipsilateral MFV decreased to a mean of 44.4% +/- 7.5% of baseline value (P < .01). In the absence of interhemispheric cross-flow and within 68 seconds, contralateral MFV decreased to 83.1% +/- 7.9% (P < .01). CONCLUSIONS: The observed decrease of contralateral MFV was not caused by amobarbital cross-perfusion. A possible underlying mechanism may be interhemispheric deafferentation.

Adult↗
PubMed2002

Glial and neuronal serum markers after controlled cortical impact injury in the rat.

The aim of this study was to investigate the time course and the correlation of glial fibrillary acidic protein (GFAP), protein S-100B, and neuron specific enolase (NSE) serum levels to the severity of traumatic brain injury in rats. Male Wistar rats (n = 65 S-100B, NSE group and n = 55 GFAP group) underwent a severe cortical impact injury (100PSI, 2 mm deformation). Blood samples were drawn directly after trauma, 1 h, 6 h, 12 h, 24 h, and 48 h post trauma as well as in sham operated animals directly after craniotomy, after 6 h and 48 h. Serum levels at different severities were estimated in 20 rats (45PSI, 75PSI, 2 mm deformation). We found a time-dependent release of NSE and GFAP into serum after trauma. The highest NSE values were detected six hours after trauma (31.5 micrograms/l, mean, p < 0.0001), the highest GFAP levels were measured one hour after trauma (0.079 microgram/l, mean, p < 0.0014). Additionally we found a close relationship between NSE serum levels and the severity of traumatic brain injury (45PSI = 12.7 micrograms/l, 75PSI = 16.17 micrograms/l, 100PSI = 28.45 micrograms/l, p < 0.05). S-100B serum levels showed an increase (0.92 microgram/l, p < 0.005) but no time-dependent release. S-100B and GFAP showed no relationship to trauma severity. Serum levels of GFAP, S-100B and NSE are significantly elevated in the early phase after experimental traumatic brain injury. In this experimental model of cortical impact injury only NSE, but not GFAP and S-100B serum levels are time-dependently correlated with the severity of cortical impact.

Animals↗
PubMed2002

An in vitro study to evaluate the accuracy of stereotactic localization using magnetic resonance imaging by means of the Leksell stereotactic system.

The advantages of using magnetic resonance imaging (MRI) as opposed to computed tomographic (CT) scans or ventriculography in stereotactic surgery include the increased tissue contrast of the lesion or target, direct non-reformatted multiplanar imaging and target coordinate determination as well as reduced imaging artefacts produced by the stereotactic frame. One disadvantage of MR stereotaxis, however, is the potential for anatomic inaccuracy due to equipment-induced inhomogeneities of the magnetic field. The authors present an experimental study on an in vitro model to examine the accuracy of target localization using the Leksell stereotactic frame and MR imaging. Ten formalin-fixed brains taken from patients who had died of non-neurological diseases were sealed in a properly modelled plaster-cast shell simulating the skull bone. These models were fixed in the Leksell stereotactic frame and high-field MR images were performed (Siemens Magnetom SP 1.5 Tesla, T1-weighted spin echo sequences, TR/TE 600/15 ms, slice thickness 2 mm, FOV 300 mm). Following electrocoagulation of different targets on both lentiforme nuclei, the localization and extension of the lesions were controlled by MRI. A gross-/histopathological verification was performed. This model allows a good representation of the anatomic structures without any artefacts. The postoperative MRI control and the pathological examination of the lesions matched well with the preoperatively defined targets. The correlation of coordinates and measurements obtained with the pathological studies were within a +/- 2 mm range in all cases.

Brain↗
PubMed2002

[Contrast-enhanced intracranial 3 D MR angiography (CE-MRA) in assessing arterial stenoses and aneurysms].

PURPOSE: The aim of this study was to evaluate the diagnostic potential of CE-MR angiography in intracranial arterial stenoses and aneurysms. MATERIAL AND METHODS: Thirteen patients with intracranial arterial stenoses and ten patients with aneurysms, including 6 cases with GDC coil-occluded aneurysms, were examined by both 3 D TOF-MR angiography and CE-MR angiography. In cases of stenoocclusive diseases colour-coded duplex sonography and in cases of aneurysms arterial digital subtraction angiography served as reference method. RESULTS: Both TOF-MRA and CE-MRA could well depict filiform stenosis. In contrast to TOF-MRA, CE-MRA did not show any false positive stenosis or occlusion in regions of turbulent or slow blood flow. Stenoses of the medial cerebral artery could not be graded sufficiently by CE-MRA. In aneurysms the parent vessel was better shown by TOF-MRA. CE-MRA, however, more sensitively detected reperfusion in GDC coil-occluded aneurysms. CONCLUSION: Stenoses of small vessels were graded less exactly by CE-MRA than by TOF-MRA due to lower spatial resolution. CE-MRA, however, seems to be superior in regions of turbulent or slow blood flow. CE-MRA also offers advantages in follow-up examinations of coil-occluded aneurysms.

Aged↗
PubMed2001

S-100B is increased in melancholic but not in non-melancholic major depression.

BACKGROUND: Recent evidence suggests that neurodegeneration may be involved in the pathophysiology of major depression. The astroglial peptide S-100B was shown to be increased in many diseases causing neuronal cell damage or degeneration. METHOD: S-100B plasma levels were determined in 28 patients with major depression and 28 matched healthy controls using an immunofluorometric sandwich assay. RESULTS: Patients suffering from melancholic depression showed significantly increased S-100B levels compared to healthy controls while non-melancholic patients demonstrated normal levels. LIMITATIONS: Medication of patients varied. The differentiation between melancholic and non-melancholic patients was performed clinically without using a standardized instrument. CONCLUSIONS: Neurodegeneration or axonal remodeling may be involved in the pathogenesis of melancholic depression.

Adult↗
PubMed2001

Increased S100B blood levels in unmedicated and treated schizophrenic patients are correlated with negative symptomatology.

S100B, a calcium-binding protein produced by astroglial cells, is a marker of astroglial cellular integrity. It has been shown to be increased in acute brain damage and neurodegeneration. A recent study showed increased S100B levels in medicated acutely psychotic patients with schizophrenia. The study presented here included 26 drug-free patients with acute schizophrenia and 26 matched healthy controls. S100B blood concentrations were determined using a quantitative immunoassay upon admission and after 6 weeks of neuroleptic treatment. The PANSS was used to investigate psychopathology. Unmedicated schizophrenic patients showed significantly increased S100B levels compared to matched healthy controls. After 6 weeks of treatment, 11 patients showed normal S100B levels while in 15 patients the levels remained increased. These patients showed significantly higher PANSS negative scores upon admission and after 6 weeks of treatment. Schizophrenic patients display a loss of astroglial integrity which is not caused by neuroleptic medication. Continuously increased S100B levels are associated with negative symptomatology.

Adult↗
PubMed2000

Three-dimensional reconstructed rotational digital subtraction angiography in planning treatment of intracranial aneurysms.

We evaluated three-dimensional (3D) reconstructions of 200 degrees rotational digital subtraction angiography (DSA) images for their contributions to improving the safety of endovascular embolization of intracranial aneurysms. Standard DSA and 200 degrees rotational DSA were performed in 40 adult patients (aged 21-77 years) with 45 intracranial aneurysms. Information obtainable from standard DSA and 3D-DSA images about aneurysm shape and size was compared. In 40 (89%) of the 45 aneurysms 3D-DSA gave additional information about the anatomy of the aneurysm. In 17 (43 %) of these cases aneurysm anatomy could be visualized better on 3D-DSA than on standard DSA images. In three cases only 3D-DSA images showed blood vessels originating from the aneurysm. Reconstructed 3D images were also helpful in visualizing partially clipped aneurysms. On maximum-intensity projection images it was even possible to depict previously embolized aneurysms. Blood vessels originating from the aneurysm are visible on 3D-DSA images, and even previously clipped aneurysms can be visualized well. Rotational DSA with 3D reconstruction is a helpful tool in the assessment of intracranial aneurysms.

Adult↗
PubMed2000

Cavernous angioma as a rare neuroradiologic finding in the cavernous sinus.

We report the case of a 56-year-old female with a pathologically confirmed cavernous angioma of the cavernous sinus. There are only a few reports on cavernous sinus angiomas in the literature. In contrast to typical intracerebral cavernous angiomas, these lesions are characterized by strong contrast enhancement on computed tomography and magnetic resonance imaging. In spite of the problematic location within the cavernous sinus, these angiomas can be completely resected without additional neurologic deficits. The clinical course of the patient and the unusual neuroradiologic imaging findings, as well as the cases from the literature are discussed.

Cavernous Sinus↗
PubMed2000

[Main symptom: "pulse-synchronous tinnitus"].

BACKGROUND: In comparison to cochlear or nerval generated ear noises, pulsatile tinnitus is a rare condition. Due to its own etiology, specific diagnostic steps are necessary. PATIENTS: We present 6 patients with pulsating tinnitus as the leading symptom. By means of these cases the various etiologies, rational diagnosis and therapy will be discussed. RESULTS: Pulsatile tinnitus is frequently caused by an increased blood flow in the cranial vessels through various pathologies. Besides those diseases going along with a general increase of blood circulation, regional alterations can be classified as hypervascular/hyperemic, arterial or venous conditioned. CONCLUSIONS: Physical examination and modern imaging can detect the underlying reasons in a quick and reliable way.

Adult↗
PubMed2000

Dynamic CT perfusion imaging of acute stroke.

BACKGROUND AND PURPOSE: Because cerebral perfusion imaging for acute stroke is unavailable in most hospitals, we investigated the feasibility of a method of perfusion scanning that can be performed rapidly during standard cranial CT. Our aim was to identify the scanning parameters best suited to indicate tissue at risk and to measure a perfusion limit to predict infarction. METHODS: Seventy patients who had suffered stroke and had undergone cranial CT 0.5 to 12 hours (median, 3.75 hr) after the onset of symptoms participated in the study. While undergoing conventional CT, each patient received a bolus of iodinated contrast medium. Maps of time to peak (TTP), cerebral blood volume (CBV), and CBF were calculated from the resulting dynamically enhanced scans. These perfusion images were compared with follow-up CT scans or MR images showing the final infarctions. RESULTS: CBF maps predicted the extent of cerebral infarction with a sensitivity of 93% and a specificity of 98%. In contrast, CBV maps were less sensitive and TTP maps were less specific and also showed areas of collateral flow. Infarction occurred in all of the patients with CBF reduction of more than 70% and in half of the patients with CBF reduction of 40% to 70%. CONCLUSION: Dynamic CT perfusion imaging safely detects tissue at risk in cases of acute stroke and is a feasible method for any clinic with a third-generation CT scanner.

Acute Disease↗
PubMed1999

Elevated plasma levels of S-100b protein in schizophrenic patients.

BACKGROUND: In this study, we examined the possibility that structural damage to the brain may play a role in the pathogenesis of schizophrenia. METHODS: We compared plasma levels of S-100b protein in 20 patients with schizophrenic psychosis and 20 age- and gender-matched healthy blood donors. Concentrations of S-100 protein were determined by microtiter-based immunofluorometric assay detecting predominantly S-100b. RESULTS: Mean concentrations of S-100b protein in blood were significantly (p < or = .001) higher in schizophrenic patients (0.165 +/- 0.138 microgram/L) compared to control subjects (0.054 +/- 0.031 microgram/L). Levels did not correlate with age of onset or duration of psychosis. CONCLUSIONS: Our findings indicate that patients with schizophrenia may suffer ongoing structural damage to cells of the central nervous system, and that the concentration of S-100b protein in plasma may help to identify clinical subgroups in schizophrenia.

Adult↗
PubMed1999

Pituitary apoplexy after cardiac surgery presenting as deep coma with dilated pupils.

Acute clinical deterioration due to infarction or haemorrhage of an existing, often previously unrecognized, pituitary tumour is a rare but well-described complication. It can occur spontaneously or may be caused e.g. by mechanical ventilation, infection or surgical procedures. We report on a case of pituitary apoplexy occurring in a 64-year-old patient 3 weeks after cardiac surgery. The patient presented with deep coma and dilated pupils. Magnetic resonance imaging revealed a haemorrhagic pituitary tumour. After prompt endocrinologic replacement therapy with levothyroxine and hydrocortisone the patient regained consciousness. Neurological examination revealed right oculomotor nerve palsy and bilateral cranial nerve VI palsy. Subsequent trans-sphenoidal removal of a nonfunctional macroadenoma with large necrotic areas was performed. The patient recovered completely. To our knowledge, pituitary tumours presenting with a combination of deep coma and dilated pupils must be considered exceedingly rare. Possible pathophysiologic mechanisms are discussed. As our case illustrates, even in severe cases complete recovery is possible if the diagnosis is suspected, and diagnostic and therapeutic measures are initiated in time.

Coma↗