PubMed Health⌕ Search

Biomedical subjects

Georg Bohner

Publications and source records attributed to Georg Bohner.

7 recordsLinked to original sources
PubMed2006

Pineal calcification in Alzheimer's disease: an in vivo study using computed tomography.

Melatonin has been postulated to have diverse properties, acting as an antioxidant, a neuroprotector, or a stabilizer within the circadian timing system, and is thus thought to be involved in the aging process and Alzheimer's disease (AD). We used computed tomography to determine the degree of pineal calcification (DOC), an intra-individual melatonin deficit marker, as well as the size of uncalcified pineal tissue, in 279 consecutive memory clinic outpatients (AD: 155; other dementia: 25; mild cognitive impairment: 33; depression: 66) and 37 age-matched controls. The size of uncalcified pineal tissue in patients with AD (mean 0.15 cm(2) [S.D. 0.24]) was significantly smaller than in patients with other types of dementia (0.26 [0.34]; P=0.038), with depression (0.28 [0.34]; P=0.005), or in controls (0.25 [0.31]; P=0.027). Additionally, the DOC in patients with AD (mean 76.2% [S.D. 26.6]) was significantly higher than in patients with other types of dementia (63.7 [34.7]; P=0.042), with depression (60.5 [33.8]; P=0.001), or in controls (64.5 [30.6]; P=0.021). These two findings may reflect two different aspects of melatonin in AD. On the one hand, the absolute amount of melatonin excretion capability, as indicated by uncalcified pineal volume, refers to the antioxidant properties of melatonin. On the other hand, the relative reduction in melatonin production capability in the individual, as indicated by DOC, refers to the circadian properties of melatonin.

Aged↗
PubMed2005

Pilocytic astrocytoma presenting as primary diffuse leptomeningeal gliomatosis: report of a unique case and review of the literature.

We describe a 25-year-old male patient with primary diffuse leptomeningeal gliomatosis (PDLG) presenting with gait ataxia, positive Lhermitte's sign, double vision, and right abducens nerve palsy. Spinal magnetic resonance imaging showed extended intradural, extramedullary, contrast-enhancing masses with compression of the myelon. Spinal leptomeningeal biopsy revealed a pilocytic astrocytoma WHO grade I. Despite chemotherapy with vincristin and carboplatin, the patient died 2 months after admission. A thorough autopsy showed no evidence for primary neoplasms in brain, spine and optic nerve. Sequence analysis of tumor protein 53 gene (TP53) revealed a missense mutation in exon 5, and expression of phosphatase and tensin homolog (mutated in multiple advanced cancers 1) (PTEN) protein was not detected, which may have contributed to astrocytoma development. To our knowledge, this is the first definitive case of pilocytic astrocytoma presenting as PDLG.

Adult↗
PubMed2004

Delayed occlusion after internal carotid artery dissection under heparin.

Internal carotid artery dissection (ICAD) is a frequent etiology of stroke in the young. Immediate anticoagulation with unfractionated heparin is the most frequent treatment. A theoretical side effect of unfractionated heparin is an increase in the intramural hematoma resulting in hemodynamic cerebral infarction. We studied 20 patients with ICAD. All patients were immediately treated with unfractionated heparin. Activated partial thromboplastin time (aPTT) ratios were measured twice daily. We prospectively monitored the course of ICAD with repeated ultrasound in hospital. Unexpectedly, delayed ICA occlusion was noted in 5 patients under treatment. One of these developed a watershed infarct. We then analyzed the aPTT ratios over the first 6 days after diagnosis. Patients with delayed occlusion had significantly higher aPTT ratios (2.6 +/- 0.4 vs. 2.0 +/- 0.5, p < 0.05). Within the limits of a partially retrospective design, our study seems to support the notion that unfractionated heparin can increase the intramural hematoma. Our findings further justify a randomized clinical trial to resolve the anticoagulant/antiplatelet debate.

Adult↗
PubMed2002

Multi-slice CT angiography in the evaluation of patients with acute cerebrovascular disease--a promising new diagnostic tool.

Single-slice computed tomographic angiography (CTA) is an established imaging method for the cerebrovascular system (CVS), but it suffers from technical limitations with respect to the coherent high resolution visualization of longer vascular segments, such as the extra- and intracranial CVS. The recently introduced multi-slice (MS) technology has been attributed with a superior imaging quality for angiographic procedures due to increased scan speed and improved spatial resolution. The purpose of this study was to evaluate the suitability of multi-slice CTA (MS-CTA) for the assessment of the arteriovenous CVS in patients with acute symptoms of either arterial or venous occlusive diseases. 41 patients with clinically suspected acute cerebral ischaemia (hemispheric in 29 and vertebrobasilar in 12 patients) and 4 patients with suspected cerebral venous thrombosis (CVT) underwent CTA in a MS-CT scanner. In addition, doppler ultrasonography (DUS) was erformed in 34, magnetic resonance angiography (MRA) in 5 and digital subtraction angiography (DSA) in 6 patients. All findings were reviewed for stenoses or occlusion of the extra-and intracranial CVS and correlated with the clinical outcome. In 43 (96%) of 45 patients, MS-CTA yielded images of diagnostic quality with comprehensive visualization of the arterial and venous CVS including the cervical carotid bifurcation, the third segment of the major cerebral arteries and the dural sinus as well as internal cerebral veins. In 2 patients, assessment of the carotid bifurcation was limited because of tooth artefacts. In all patients, in whom imaging and clinical follow-up proved a non-lacunar infarction (n = 22), MS-CTA detected the underlying vascular pathology. Suspected CVT could be confirmed in 2 and ruled out in another 2 patients through MS-CTA. In conclusion, multi-slice CT an giography may be a promising new diagnostic tool for the rapid and comprehensive assessment of the arteriovenous CVS in patients with clinical signs of acute cerebrovascular diseases.

Acute Disease↗