Search PubMed⌕ Search

Biomedical subjects

B Eckert

Publications and source records attributed to B Eckert.

At least 19 recordsLinked to original sources
PubMed2006

Rapidly progressive vanishing white matter disease in a child with previously inconspicuous brain MRI.

In this pediatric case of vanishing white matter disease with early onset, rapidly progressive course, and fatal outcome, the white matter vanishing process in patient was for the first time documented morphologically in detail: An initial magnetic resonance imaging documented a normal appearing brain maturation. Rapid progressive brain lesions initiated morphologically DE NOVO in the former well myelinated deep white matter were observed six months later after disease onset, including concentric ongoing signs of restricted proton diffusion cytotoxic edema on diffusion weighted imaging. Cyst-like defects at the lesion center of the deep white matter were detected more clearly on MRI ten months later. A pathomechanism like tumor necrosis factor induced oligodendrocyte apoptosis and primary demyelination was postulated. The case demonstrates that in the presence of clinically progressive symptoms, the development of VWM is possible even if first MRI findings are negative.

Atrophy↗
PubMed2006

The amount of solid cerebral microemboli during carotid stenting does not relate to the frequency of silent ischemic lesions.

BACKGROUND AND PURPOSE: Carotid artery stent placement (CAS) may be associated with clinically silent cerebral lesions. We prospectively evaluated the association of the number of solid cerebral microemboli during unprotected CAS with the frequency of silent cerebral lesions as detected by diffusion-weighted MR imaging (DWI). METHODS: We performed multifrequency transcranial Doppler detection of solid microemboli in the ipsilateral middle cerebral artery (MCA) during CAS in 27 consecutive patients with symptomatic high-grade carotid stenoses. No embolus protection was used in any of the cases. DWI before and 24 +/- 2 hours after CAS was used to detect new ischemic lesions. RESULTS: We detected 484 solid microemboli in 17 patients (63%). On MR imaging 24 +/- 2 hours after CAS, 6 patients (22%) had developed 13 new clinically silent DWI lesions within the ipsilateral MCA territory. In patients with Doppler evidence of solid emboli during CAS, the incidence of new DWI lesions was higher (29%) than in patients without Doppler evidence of solid emboli during the procedure (10%); this difference was not statistically significant (P = .25). The number of solid microemboli during CAS in patients with new ipsilateral DWI lesions was not significantly different from that in patients without new ipsilateral DWI lesions. CONCLUSIONS: Solid microembolism is a common event during unprotected CAS; however, the frequency of procedure-related silent cerebral lesions appears to be independent of the number of solid cerebral microemboli during the procedure.

Adult↗
PubMed2004

[Endovascular treatment of extensive carotid cavernous fistulas by superior ophthalmic vein approach. Technique and illustration of two cases].

Treatment of carotid cavernous fistulas is a domain of interventional neuroradiolgy. In rare cases, however, the cavernous sinus cannot be reached by an endovascular approach, leaving the access via the superior ophthalmic vein as the last therapeutic option. History, diagnostic findings, and operative procedure for a patient with spontaneous, indirect CCF (Barrow type D) and a patient with traumatic, direct CCF (Barrow type A) are described. In both patients, curative therapeutic success could be achieved. This article focuses on the detailed description and illustration of the combined surgical/endovascular technique.

Adult↗
PubMed2004

The diagnostic relevance of colour Doppler artefacts in carotid artery examinations.

PURPOSE: Physical and technical artefacts of the colour Doppler method are examined with regard to their diagnostic relevance for the carotid artery. MATERIALS AND METHODS: After recording all diagnostic problems arising from physical and technical artefacts in 30,000 consecutively carotid arteries, the quantitative significance of relevant artefacts was determined in minor subgroups of the collective. RESULTS: Acoustic shadowing causes diagnostic problems in morphological and haemodynamic evaluation of stenoses. Mirror image artefacts simulate flow in cases of actual vessel occlusion or mimic vessel wall ulceration in carotid plaques and stenoses. Insonation angle artefacts inhibit detection of flow or mimic flow reversal. Problems of spatial resolution lead to incorrect demonstration of the vessel lumen in stenotic findings. Aliasing, perivascular colour artefacts, and ghosting do not cause any diagnostic problems. Relevant shadowing artefacts occurred in 14.7%, and relevant mirror image artefacts in 2.5% of the pathological cases. Insonation angle artefacts occurred in 17.3% of the cases (when using standard apparatus setting). However, with an exact knowledge of the artefact phenomena, insonation angle artefacts could be eliminated and mirror image artefacts were recognized in all cases. Resolution artefacts resulted in underestimation of carotid stenoses by on average 13.3% of the degree of stenosis. CONCLUSION: In principle, four artefact phenomena give rise to diagnostic problems; however, with a good knowledge of the phenomena, only artefacts due to acoustic shadowing and limited spatial resolution are of diagnostic significance.

Arterial Occlusive Diseases↗
PubMed2003

Angiographic follow-up of vertebrobasilar artery aneurysms treated with detachable coils.

Endovascular treatment of ruptured vertebrobasilar artery aneurysms with Gugliemi detachable coils (GDC) has become an alternative to surgery. Mid-term angiographic follow-up can now be reported. Of 111 vertebrobasilar aneurysms in 110 patients we treated with GDC since 1992, 53 underwent angiography within 1 year and 59 after more than 18 months. We did not achieve complete occlusion on initial treatment of 23 aneurysms (21%). Complications were observed in 19 patients (17%), leading to permanent clinical disability in eight. Enlargement of the neck or reopening was seen in 12 (23%) of 53 aneurysms followed by angiography within 12 months. Documented recanalisation was treated in four (8%). Angiography was performed after 18-78 months in 59 patients, of whom nine, including three with initially incomplete occlusions, were retreated with GDC. Within the entire second observation period, three (5%) of the 59 patients had a further haemorrhage and were retreated with GDC. Rebleeding proved to be the only factor influencing the clinical outcome of retreated patients.

Angiography, Digital Subtraction↗
PubMed2003

Multiple vascular abnormalities and a paradoxical combination of vitamin B12 deficiency and thrombocytosis in a case with POEMS syndrome.

POEMS/Crow-Fukase syndrome is a rare multisystem disorder associated with elevated vascular endothelial growth factor (VEGF), which clinically presents with polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes. We report a case of POEMS syndrome due to a gammopathy of undetermined significance with thrombocytosis, vitamin B(12) deficiency, highly elevated VEGF and in addition to glomeruloid angiomas two previously undescribed proliferative vascular lesions: a spinal arteriovenous fistula and a plexogenic pulmonary arteriopathy, which ultimately resulted in lethal pulmonary hypertension. We assume that the high VEGF levels caused the vascular abnormalities observed in our patient.

Adult↗
PubMed2003

[Spinal dural arteriovenous fistula: clinical and radiological findings in 54 patients].

PURPOSE: Presentation of the clinical and radiological findings in spinal dural arteriovenous fistulas (SDAVF) based on the experience in 54 patients. MATERIAL AND METHODS: Evaluation of patients' records and myelography (n = 23), MRI (n = 54) as well as conventional angiography (n = 54) with respect to history, symptoms, clinical and radiological results. RESULTS: Clinically, a long history (mean 20 months) with progressive ascending paresis (100 %), sensory deficits (93 %) and loss of control over bladder and bowel function (89 %) in male patients (78 %) of advanced age (mean 60 years) indicates the disease. Typical signs in MRI are central cord hyperintensity (100 %) with slight medullary distension (74 %), contrast enhancement (79 %) and distended perimedullary veins (89 %), the latter being disclosed by myelography in 78 % of cases. For diagnosis spinal angiography is necessary which most often shows a thoracic location of the fistula (69 %), more than one feeding artery (67 %) and caudal as well as rostral venous drainage (63 %). CONCLUSION: MRI is superior to myelography to detect diagnostic signs of SDAVF in patients with typical clinical presentation. For definitive diagnosis spinal angiography is still indispensable.

Adult↗
PubMed2002

Collateral circulation is an independent radiological predictor of outcome after thrombolysis in acute ischaemic stroke.

We tested the hypothesis that the type of vascular occlusion, recanalisation and collateralisation are predictive of outcome after thrombolytic therapy in acute ischaemic stroke. We carried out angiography and local intra-arterial (97) or systemic (14) thrombolysis within 6 h of the onset in patients with an ischaemic stroke in the territory of the internal carotid artery. Early ischaemic signs (EIS) on pretreatment CT and angiographic findings were classified and analysed in relation to clinical outcome at 3 months. A favourable outcome (Barthel index [BI]>/= 90) was found in 40% of patients with an occlusion of the middle cerebral artery trunk whereas intracranial occlusion of the internal carotid artery ("carotid T occlusion") was followed by death or severe disability (BI<50) in 87%. Significant univariate predictors of favourable outcome were occlusion type ( P<0.01), recanalisation ( P<0.01) and collateralisation ( P<0.01). However, multivariate analysis revealed a significant relationship only between collateralisation and favourable outcome (odds ratio 5.9, 95% confidence interval 1.3-26.7, P=0.02). EIS were not predictive in either case. Occlusion type and recanalisation, are related to outcome only if adequate collateralisation prevents infarction until recanalisation occurs.

Acute Disease↗
PubMed2002

[Endovascular therapy of high-degree stenoses of the neck vessels-stent-supported percutaneous angioplasty of the carotid artery without cerebral protection].

PURPOSE: Technical essentials and therapeutic results of carotid stenting without cerebral protection are presented. MATERIALS AND METHODS: In 161 patients, 167 high grade carotid stenoses were stented, followed by percutaneous transluminal angioplasty, with subsequent evaluation of the clinical and angiographic results. Diffusion-weighted MRI was carried out in 108 patients to detect cerebral sequelae. RESULTS: Endovascular therapy was successful (residual stenosis < 25 %) in 166 stenoses (99.4 %). Twelve patients (7.5 %) had cerebrovascular complications within the 30-day perioperative period, seven of which occurred during the procedure. After treatment, diffusion-weighted MRI disclosed at least one new cerebral lesion in 40 patients (37 %), which were symptomatic in six patients. CONCLUSION: Even without cerebral protection, high grade carotid stenosis can be safely treated with stent-protected percutaneous angioplasty. Microemboli detected by postoperative MRI are infrequently symptomatic.

Adult↗
PubMed2001

Herbaspirillum frisingense sp. nov., a new nitrogen-fixing bacterial species that occurs in C4-fibre plants.

The enrichment of nitrogen-fixing bacteria from the C4-fibre plants, Spartina pectinata, Miscanthus sinensis, Miscanthus sacchariflorus and Pennisetum purpureum, with nitrogen-free semi-solid media led to the isolation of Herbaspirillum-like strains among other diazotrophic bacteria. On the basis of physiological properties, phylogenetic analysis comparing 16S rDNA sequences and DNA-DNA hybridization experiments of chromosomal DNA the new isolates could be grouped together in a new species with the proposed name Herbaspirillum frisingense sp. nov. Morphological characteristics, such as cell size and shape, colony appearance, motility and flagellation are largely identical to the known species Herbaspirillum rubrisubalbicans and Herbaspirillum seropedicae. On the basis of utilization of adipate (-), N-acetyl-D-glucosamine (+), meso-erythritol (-), L-rhamnose (-) and meso-inositol (-) Herbaspirillum frisingense sp. nov. can be distinguished from other known Herbaspirillum spp. Nitrogen-fixing capability was examined by PCR amplification of the nifD gene and an acetylene reduction assay, and was found with all isolates tested. 16S rDNA sequence similarity to the other Herbaspirillum spp. is 98.5-99.1%. In genomic DNA-DNA hybridization experiments Herbaspirillum frisingense sp. nov. forms a homogeneous group with 70-100+/-10% similarity, clearly distinct from Herbaspirillum seropedicae and Herbaspirillum rubrisubalbicans with 1-34% similarity. 16S rRNA-targeted oligonucleotide probes, specific for the whole genus Herbaspirillum and for three Herbaspirillum species were designed and are suitable for fluorescence in situ hybridization. The DNA G+C content of Herbaspirillum frisingense sp. nov. is 63+/-2 mol%, in agreement with the values of 61-65% for the genus. PCR fingerprinting exhibits a consistent pattern for groups of strains isolated from the same plant, suggesting a low genomic diversity among bacteria inhabiting C4-gramineous plant tissues. Low genetic DNA diversity seems to be common between probable endophytic bacterial isolates of the same taxon. The type strain of Herbaspirillum frisingense sp. nov. is GSF30T (= DSM 13128T).

Base Composition↗
PubMed2001

Azospirillum doebereinerae sp. nov., a nitrogen-fixing bacterium associated with the C4-grass Miscanthus.

A new group of nitrogen-fixing Azospirillum sp. bacteria was isolated from the roots of the C4-gramineous plant Miscanthus. Polyphasic taxonomy was performed, including auxanography using API galleries, physiological tests and 16S rRNA sequence comparison. The ability of the isolates to fix dinitrogen was evaluated by amplification of the nifD gene, immunodetection of the dinitrogenase reductase and acetylene-reduction assay. On the basis of these results, the nitrogen-fixing isolates represent a new species within the genus Azospirillum. Its closest phylogenetic neighbours, as deduced by 16S rDNA-based analysis, are Azospirillum lipoferum, Azospirillum largimobile and Azospirillum brasilense with 96.6, 96.6 and 95.9% sequence similarity, respectively. Two 16S rRNA-targeting oligonucleotide probes were developed which differentiate the new species from the other Azospirillum species by whole-cell fluorescence hybridization. Strains of the new species are curved rods or S-shaped, 1.0-1.5 microm in width and 2,0-3.0 microm in length, Gram-negative and motile with a single polar flagellum. Optimum growth occurs at 30 degrees C and at pH values between 6.0 and 7.0. No growth takes place at 37 degrees C. They have a respiratory type of metabolism, grow well on arabinose, D-fructose, gluconate, glucose, glycerol, malate, mannitol and sorbitol. They differ from A. largimobile and A. lipoferum by their inability to use N-acetylglucosamine and D-ribose, from A. lipoferum by their ability to grow without biotin supplementation and from A. brasilense by their growth with D-mannitol and D-sorbitol as sole carbon sources. Nitrogen fixation occurs in microaerobic nitrogen-limited conditions. For this species, the name Azospirillum doebereinerae sp. nov. is suggested, with strain GSF71T as the type strain (= DSM 13131T; reference strain Ma4 = DSM 13400). Its G+C content is 70.7 mol%.

Azospirillum↗
PubMed1999

Individualized low-dose growth hormone (GH) treatment in GH-deficient adults with childhood-onset disease: metabolic effects during fasting and hypoglycemia.

Growth hormone (GH) has insulin-antagonistic effects, and GH secretion is augmented during fasting and hypoglycemia. In the present study, 10 patients aged 21 to 28 years with childhood-onset GH deficiency (GHD) were studied during a 24-hour fast and a hypoglycemic glucose clamp before and after 9 months of GH replacement. During the 24-hour fast, blood glucose, serum insulin, and serum free fatty acid (FFA) levels were measured. In the hypoglycemic clamp, the counterregulatory hormones (plasma catecholamines, serum glucagon, and serum cortisol), serum insulin-like growth factor (IGF) binding protein-1 (IGFBP-1), serum FFA, and glucose uptake were measured. The GH dose was adjusted to the response of serum IGF-I, and the median GH dose was 0.14 IU/kg/wk (range, 0.08 to 0.19). At the end of the study, serum IGF-I levels were normalized in all but one patient, in whom serum IGF-I was above the normal range. Nine months of GH treatment did not cause any significant changes in the blood glucose level, insulin to glucose ratio, or serum FFA level during the 24-hour fast, and none of the patients experienced hypoglycemia either before or after GH treatment. However, GH therapy resulted in increased insulin resistance during hypoglycemia, without changes in the counterregulatory hormonal responses, serum IGFBP-1, or serum FFA.

Adult↗
PubMed1998

Sustained elevation of cerebral blood flow after hypoglycaemia in normal man.

During hypoglycaemia, counter-regulatory hormones are released, cognitive function is impaired and cerebral blood flow is increased. In the immediate period after normalisation of blood glucose only counter-regulatory hormones seem to be normalised. The aim of this study was to follow the changes in cerebral blood flow during a prolonged recovery period following moderate hypoglycaemia in normal man. In 15 healthy men, hypoglycaemia was induced by an intravenous infusion of insulin (2.5 mU/kg per min) to a blood glucose of 2.2 +/- 0.3 mmol/l (mean +/- S.D.) and was kept at this level for 66 +/- 11 min. The cerebral blood flow was measured by a single photon emission computed tomography camera (SPECT) recording the clearance of intravenously administered xenon-133. Measurements were performed before, at the beginning and at the end of the hypoglycaemic period, as well as 23 +/- 5, 51 +/- 7 and 97 +/- 7 min after normalisation of the blood glucose. The basal cerebral blood flow was 50.2 +/- 5.2 ml/100 g per min, increased to 55.6 +/- 4.9 ml/100 g per min (P < 0.001) during hypoglycaemia, and remained at this level at all measurements after normalisation of blood glucose. There was no relation between the rate of fall in blood glucose or level of hypoglycaemia and increment in cerebral blood flow or the actual blood flow during hypoglycaemia. The values of plasma adrenaline, serum ACTH, serum cortisol and symptom scores increased significantly during hypoglycaemia. The adrenaline level was back to the basal level at the first measurement after normalisation of blood glucose, while the ACTH level was normalised at the subsequent measurement and the cortisol level at the last measurement. In conclusion, the results show that despite normalisation of counter-regulatory hormones and hypoglycaemic symptoms, the cerebral blood flow remains elevated for at least 97 +/- 7 min following 66 +/- 11 min of moderate hypoglycaemia, indicating that additional factors which are not coupled to the cerebral metabolism influence this vasculatory response.

Adrenocorticotropic Hormone↗
PubMed1998

Hypoglycaemia leads to an increased QT interval in normal men.

Hypoglycaemia is presumed to be the cause of death in about 3% of insulin-treated diabetic patients. Some of these patients suffer from hypoglycaemic brain damage, but the majority have no evident brain damage and are supposed to have died from other causes such as a cardiac arrhythmia. The putative mechanism is a hypoglycaemia-induced prolongation of the QT interval which increases the risk of malignant ventricular tachycardia. The aim of the present study was to examine the electrocardiogram during and after hypoglycaemia in healthy men. To that end, hypoglycaemia was induced by an intravenous infusion of insulin (2.5 mU kg-1 min-1) in 10 healthy men to reach a venous blood glucose level of 2.1 +/- 0.3 mmol l-1 for 65 +/- 9 min. Before hypoglycaemia, after 20 and 50 min of hypoglycaemia and 20 and 45 min after normalization of the blood glucose, the QT interval was measured by a ruler and corrected for the heart rate. Results are given as mean +/- SD and comparisons were made with an ANOVA, except for symptom scores and plasma adrenaline where non-parametric tests were used. When this indicated significance, further analysis was performed with a two-tailed t-test. During hypoglycaemia the corrected QT interval increased from 380 +/- 20 ms1/2 to 440 +/- 30 ms1/2 (P < 0.001), and the amplitude of the T wave decreased (P = 0.002). The serum potassium level decreased from 4.3 +/- 0.3 mmol l-1 to 3.5 +/- 0.2 mmol l-1 (P < 0.001) and the plasma adrenaline concentration increased from 0.20 +/- 0.04 nmol l-1 to 2.46 +/- 2.58 nmol l-1 (P < 0.01). The results of this study confirm that a prolongation of the QT interval occurs during hypoglycaemia, but the significance of this finding still has to be proven.

Adult↗
PubMed1998

Predicting hemodynamic ischemia by transcranial Doppler monitoring during therapeutic balloon occlusion of the internal carotid artery.

PURPOSE: Our objective was to evaluate the sensitivity of transcranial Doppler (TCD) sonographic monitoring during permanent balloon occlusion of the internal carotid artery (ICA) in predicting hemodynamic ischemia. METHODS: Thirty-two consecutive patients underwent controlled therapeutic balloon occlusion of the ICA. Selection criteria included assessment of the circle of Willis by compression angiography, clinical tolerance during a 20-minute test occlusion, and TCD monitoring of the ipsilateral middle cerebral artery. The mean blood flow velocity (MBFV) (n = 32) and pulsatility index (PI) (n = 28) were recorded. In 25 patients, MBFV changes upon motor stimulation were recorded before and after ICA occlusion. RESULTS: Twenty-eight (88%) of the patients had no complications. Three patients suffered delayed symptoms 30 minutes to 20 hours after balloon detachment. Two of these patients recovered spontaneously within 1 day, the other improved after extracranial/intracranial (EC/IC) bypass surgery. One patient, who did not tolerate the test occlusion, suffered a hemodynamic stroke despite EC/IC bypass before permanent balloon occlusion. No embolic complications occurred. The mean MBFV reduction was 20% (range, 0% to 55%); the mean PI reduction was 20% (range, 0% to 56%). No complications occurred in patients who had mild MBFV and PI reduction (30% or less, n = 21). All three patients with severe MBFV or PI reduction (> 50%) had neurologic symptoms. Among those with moderate MBFV or PI reduction (30% to 50%, n = 8), symptoms developed in only one patient who had moderate reduction of both MBFV (33%) and PI (38%). Motor vasoreactivity showed wide variation and was markedly reduced in two symptomatic patients. CONCLUSION: TCD monitoring reflects changes in cerebral hemodynamics after therapeutic balloon occlusion of the ICA. MBFV and PI reductions under 30% are highly predictive of clinical tolerance. A reduction of more than 50% may be a critical threshold for the occurrence of symptoms; in such cases, EC/IC bypass should be considered before proceeding with permanent balloon occlusion.

Adolescent↗
PubMed1997

Transcranial Doppler Sonographic monitoring during percutaneous transluminal angioplasty of the internal carotid artery.

Our purpose was to assess the haemodynamic changes in the ipsilateral middle cerebral artery (MCA) during and after percutaneous transluminal angioplasty (PTA) of the internal carotid artery (ICA), and to compare them with clinical and angiographic findings. Transcranial Doppler Sonographic monitoring (TCD) of the MCA was performed during PTA in 22 patients with symptomatic severe stenosis of the ICA. Mean blood flow velocity (MBFV) and pulsatility index (PI) were recorded. During PTA, MBFV fell from 41 +/- 15 cm/s to 23 +/- 11 cm/s (P = 0.0001). Changes in PI were inconsistent. With reduction of MBFV of 50% or less (in 10 cases) no complication occurred. With a reduction of more than 50% (in 12), 6 patients developed neurological disturbances (transient ischaemic attacks in 5 and minor stroke in 1). This difference was significant (P = 0.0152). Symptomatic patients also had a higher rate of stroke prior to PTA (4/6) than patients who remained asymptomatic during PTA (0/6). After PTA had been performed MBFV and PI improved significantly (P = 0.0001), MBFV increasing to 48 +/- 16 cm/s and PI from 0.64 +/- 0.11 to 0.86 +/- 0.15. TCD changes proved more sensitive to cerebral haemodynamics than angiography in 8 patients.

Aged↗