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Biomedical subjects

A Kunze

Publications and source records attributed to A Kunze.

14 recordsLinked to original sources
PubMed2006

30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients: a randomised non-inferiority trial.

BACKGROUND: Carotid endarterectomy is effective in stroke prevention for patients with severe symptomatic carotid-artery stenosis, and carotid-artery stenting has been widely used as alternative treatment. Since equivalence or superiority has not been convincingly shown for either treatment, we aimed to compare the two. METHODS: 1200 patients with symptomatic carotid-artery stenosis were randomly assigned within 180 days of transient ischaemic attack or moderate stroke (modified Rankin scale score of < or =3) carotid-artery stenting (n=605) or carotid endarterectomy (n=595). The primary endpoint of this hospital-based study was ipsilateral ischaemic stroke or death from time of randomisation to 30 days after the procedure. The non-inferiority margin was defined as less than 2.5% on the basis of an expected event rate of 5%. Analyses were on an intention-to-treat basis. This trial is registered at Current Controlled Trials with the international standard randomised controlled trial number ISRCTN57874028. FINDINGS: 1183 patients were included in the analysis. The rate of death or ipsilateral ischaemic stroke from randomisation to 30 days after the procedure was 6.84% with carotid-artery stenting and 6.34% with carotid endarterectomy (absolute difference 0.51%, 90% CI -1.89% to 2.91%). The one-sided p value for non-inferiority is 0.09. INTERPRETATION: SPACE failed to prove non-inferiority of carotid-artery stenting compared with carotid endarterectomy for the periprocedural complication rate. The results of this trial do not justify the widespread use in the short-term of carotid-artery stenting for treatment of carotid-artery stenoses. Results at 6-24 months are awaited.

Aged↗
PubMed2006

Multiple reversible MR signal changes caused by Epstein-Barr virus encephalitis.

This report presents the imaging findings of an unusual case of Epstein-Barr virus (EBV) encephalitis. A young man presented with a short-lasting history of febrile infection, neuropsychologic deficits, ataxia, and seizures. MR imaging revealed fully reversible signal intensities (T2, diffusion-weighted imaging with a decreased apparent diffusion coefficient) in the splenium of the corpus callosum and both posterior hemispheres. EBV infection must be added to the list of differential diagnoses of (reversible) splenial lesions.

Adult↗
PubMed2005

Localized reversible reduction of apparent diffusion coefficient in transient hypoglycemia-induced hemiparesis.

BACKGROUND AND PURPOSE: The pathophysiology of hypoglycemia shares a common mechanism with cerebral ischemia, but so far, little is known regarding MRI of humans with hypoglycemia. METHODS: We report a patient with left hemiparesis and dysarthria associated with a blood glucose level of 1.7 mmol/L. The patient recovered completely after glucose infusion. RESULTS: The initial diffusion-weighted imaging (DWI) showed increased signal intensities and a reduction of apparent diffusion coefficient (ADC) values localized in the corpus callosum (splenium) and asymmetrically in the corona radiata. After 48 hours, follow-up revealed complete recovery of DWI and ADC signal abnormalities. CONCLUSIONS: To our knowledge, this is the first presentation of a case with transient hypoglycemia-induced focal neurological deficits revealing completely reversible MRI changes in terms of disturbed DWI and ADC with a peculiar as yet undescribed topography.

Aged↗
PubMed2004

The Stent-Supported Percutaneous Angioplasty of the Carotid Artery vs. Endarterectomy Trial.

The Stent-Supported Percutaneous Angioplasty of the Carotid Artery versus Endarterectomy (SPACE) Trial is investigating if both treatment modalities are equivalent in the treatment of severe symptomatic carotid stenoses. Patients with symptomatic (transient ischaemic attack or minor stroke) stenosis (above 50% following the North American Symptomatic Endarterectomy Trial criteria) eligible for both methods can be recruited into this trial. The primary endpoint is the incidence of an ipsilateral stroke or death between randomisation and day 30 after treatment. Surgeons as well as the interventionalists have to demonstrate their expertise prior to participation in the trial. Funding is mostly by public institutions (Federal Ministry of Education and Research and German Research Foundation). An external monitoring is applied. Thirty-two centres are currently taking part in the SPACE Trial that has been running in Germany, Austria and Switzerland for 3 years, and they have been able to recruit a total of around 670 patients. The definitive results of this study cannot be expected before 3-5 years.

Angioplasty↗
PubMed2004

[Indications for treating stenoses of the carotid artery].

The annual stroke risk for patients with asymptomatic stenoses of the carotid artery is around 1% in case of <70% stenosis (NASCET criteria) and 2-5% in patients with >70% stenosis. The risk of recurrent ischemic events for patients with symptomatic stenoses is much higher, around 15% during the first year. For more than 10 years, the efficacy of carotid surgery has been proven, and there is growing evidence to support surgery in case of asymptomatic stenosis. Patients with severe stenoses, male or elderly patients, and those with bilateral stenoses benefit more from surgery. Carotid artery stenting has not proven its safety or efficacy. Despite this lack of evidence, the method is used in many centers as an alternative to surgery. Especially symptomatic carotid artery stenosis should be used mainly in the setting of a randomized trial such as SPACE.

Angioplasty, Balloon↗
PubMed2004

[Thrombotic thrombocytopenic purpura. Reduced activity of von Willebrand factor cleaving protease].

Thrombotic thrombocytopenic purpura (TTP) is a rare thrombotic microangiopathy. Besides anemia and thrombocytopenia, neurological impairment is common in TTP. A 42-year-old woman was admitted to a department of obstetrics/gynecology because of severe vaginal bleeding due to thrombocytopenia. After platelet transfusion, the patient developed a reduced level of consciousness, confusion, headache, and fever. CT scan did not show pathological changes. Transcranial Doppler sonography revealed increased blood flow velocities of all basal cerebral arteries. Because encephalitis was suspected the patient was transferred to the neurological department. CSF and cerebral magnetic resonance imaging studies were normal. Finally, the detection of schistocytes in the peripheral blood smear and the strong elevation of LDH led to the diagnosis of TTP. After plasma exchange over 3 consecutive days the patient achieved complete remission. The diagnosis was confirmed by laboratory tests (activity of ADAMTS13 <5%, IgG antibodies against ADAMTS13). Platelet transfusion may adversely affect the outcome of patients with suspected TTP. Severely deficient activity of the von Willebrand factor cleaving protease (ADAMTS13) is specific for thrombotic thrombocytopenic purpura.

ADAM Proteins↗
PubMed2003

[Evaluation of stent-protected angioplasty for theray of symptomatic stenoses of the carotid artery. SPACE and other randomized trials].

During recent years, stent-protected angioplasty of the carotid artery (SPAC) has become an alternative to endartectomy (CEA) in many centers. Despite many case reports, case series, and open records, it has not been proven that these therapeutical regimens are comparable regarding complication rates and long-term outcome. Until now, only three randomized trials were published on this theme, two of them only as abstracts. This is not sufficient for answering the question of whether SPAC is a good alternative to CEA. At present, four major, randomized, multicenter trials are being run (EVA3S in France, CREST in the US, ICSS in Great Britain and several other countries, and SPACE in Germany and Austria). About 7,300 patients will be included in these trials. At present, 24 centers are participating in the SPACE trial, recruiting about 350 patients. It has been prospectively agreed that EVA-3S, ICSS, and SPACE will combine their results after completion of initial randomization and follow-up to conduct a combined European meta-analysis of the data. Three to 5 years are needed until these trials' final results will be published. Until then, stent-protected angioplasty should be done only under the consideration that it has not been scientifically evaluated.

Angioplasty, Balloon↗
PubMed2003

Prothrombin G20210A mutation, but not factor V Leiden, is a risk factor in patients with persistent foramen ovale and otherwise unexplained cerebral ischemia.

BACKGROUND: Paradoxical embolism via persistent foramen ovale (PFO) is suspected to be a frequent cause of stroke in younger patients. We investigated whether the prevalence of the risk factors for venous thrombosis factor V Leiden (FVL) and prothrombin G20210A mutation (PT G20210A) is increased in this group of patients. METHODS: We examined FVL and PT G20210A mutation in 220 patients (group 1) with cerebral ischemia associated with a PFO and without other etiology, in 196 patients with cerebral ischemia of an etiology other than PFO (group 2), and in 362 healthy subjects (group 3) from the same region in Germany. RESULTS: Heterozygosity for the PT G20210A mutation was more common in group 1 (5.0%) than in group 3 (1.4%; sex- and age-adjusted odds ratio 3.66; 95% CI 1.25-10.75; p = 0.01). By contrast, the mutation was not more common in group 2 (2.6%; odds ratio 1.50; 95% CI 0.42-5.41; p = 0.5). Prevalences of FVL were not different between groups. CONCLUSIONS: We identified PT G20210A but not FVL - the strongest genetic risk factor for deep venous thrombosis - to be significantly associated with stroke attributed to PFO. These findings rise doubts about the concept of paradoxical brain embolism as the dominating mechanism in stroke associated with PFO.

Adult↗
PubMed2002

[Problems of differential diagnosis in tick-borne encephalitis-induced polyradiculitis].

In about 10% of cases, tick-borne encephalitis (TBE) presents with additional myeloradiculitic features mimicking acute poliomyelitis, which can rarely appear as the sole symptom. We report on a 59-year-old man infected with TBE in Thuringia,Germany, who developed polyradiculitis with rapidly progressive, predominantly proximal tetraparesis and respiratory failure. We discuss the differential diagnosis and the epidemiological relevance in conjunction with a second typical case of TBE acquired in the same region and time period.

Antibodies, Viral↗
PubMed2000

Application of model-predictive control based on artificial neural networks to optimize the fed-batch process for riboflavin production.

The fed-batch process for commercial production of riboflavin (vitamin B2) was optimized on-line using model-predictive control based on artificial neural networks (ANNs). The information required for process models was extracted from both historical data and heuristic rules. After each cultivation the process model was readapted off-line to include the most recent process data. The control signal (feed rate), however, was optimized on-line at each sampling interval. An optimizer simulated variations in the control signal and assessed the forecasted model outputs according to an objective function. The optimum feed profile for increasing the product yield (YB2/S) and the amount of riboflavin at the time of harvesting was adjusted continuously and applied to the process. In contrast to the control by set-point profiles, the novel ANN-control is able to react on-line to variations in the process and also to incorporate the new process information continuously. As a result, both the total amount of riboflavin produced and the product yield increased systematically by more than 10% and the reproducibility of seven subsequently optimized batches was enhanced.

Algorithms↗
PubMed2000

Nitrogen-capped pi-prismands: syntheses and conformational analyses

[structure: see text] The one-pot syntheses of the new diazabicyclophanes 5-7 are described. The benzene rings incorporated in the bridging chains exhibit rotational motion which is examined by means of variable-temperature NMR experiments and semiempirical calculations. X-ray analysis and NMR studies indicate that the metal ion in the endohedral silver(I) complex of 7 fluctuates between the two nitrogen atoms.

Journal Article↗
PubMed2000

High-dose clodronate therapy prevents joint destruction in chronic antigen-induced arthritis of the rat but inhibits bone formation at the axial skeleton.

OBJECTIVE: To investigate the effects of clodronate on clinical disease activity, inflammatory alterations and cartilage destruction, periarticular and axial bone volume and bone turnover in chronic antigen-induced arthritis (AIA; day 28). METHODS: Rats with AIA were treated with clodronate (5 mg/kg/day continuously; 20 mg/kg/day intermittently or high-dose with 300 mg/kg 3 hours after arthritis induction +20 mg/kg/day continuously, respectively). Joint pathology was examined by histology. Bone volume and cellular turnover parameters of the right tibia head and the third lumbar vertebra were evaluated by histomorphometry. The findings were compared with those of healthy controls, sham-treated AIA and AIA treated continuously with 250 microg/kg of dexamethasone. RESULTS: All three therapy regimens with clodronate resulted in a significant reduction of joint swelling, histopathological inflammatory changes and cartilage destruction in comparison with sham-treated AIA. The antiinflammatory effect of high-dose clodronate was comparable with dexamethasone. The intermittent administration of 20 mg/kg/day of clodronate completely prevented periarticular bone loss by reduction of bone resorption without affecting bone formation at the periarticular and axial bone. Both continuous treatment with 5 mg/kg/day of clodronate and high-dose clodronate therapy partially prevented periarticular bone loss and reduced parameters of bone formation at the axial bone to values below those of healthy controls. CONCLUSION: High-dose clodronate therapy exerts an excellent preventive effect on clinical disease activity and on joint destruction in AIA. However, continuous treatment with high doses of clodronate may result in a low turnover state of bone remodelling.

Animals↗
PubMed2000

Clinical significance of saccade analysis in early active Graves' ophthalmopathy.

PURPOSE: To assess whether saccadic eye movements show distinct changes in patients with early active Graves' ophthalmopathy (GO), which could serve as a diagnostic tool for early detection and treatment. METHODS: Each of two prospective studies included 10 patients with early acute GO and 10 age- and sex-matched control subjects. In the explorative study (ES) 15 dynamic parameters of saccades were analyzed. In the comparative study (CS) only those parameters were evaluated, which in ES had shown significant differences between patients and controls. Horizontal and vertical saccades of 10 degrees, 20 degrees, and 40 degrees including a fatigue test were recorded binocularly using the induction scleral search coil. RESULTS: The differences of saccadic dynamics between patients and controls were small, whereas intra- and interindividual standard deviations were large. In ES, 7.1% of the parameters showed significant differences at a level of P < or = 0.05. In CS, 2.1% of all parameters revealed repetitive significant differences. Despite statistical significance, individual data did not allow differentiation between patients and healthy individuals due to high standard deviations. CONCLUSIONS: In early active GO no clinically relevant saccadic changes were detected. These findings may be based on adaptation of the central saccadic generator. Inclusion of patients with fibrotic muscle changes due to long-standing disease could explain the contrasting results of previous studies. Consequently, analysis of saccades does not serve as a diagnostic tool during early active GO.

Acute Disease↗