Die Wirkung intrathekaler Baclofenapplikation auf die Freisetzung von Adrenalin, Noradrenalin und Homovanillinsäure aus dem Nucleus paraventricularis hypothalami der Ratte

Einleitung: In der klinischen Beobachtung an Patienten, die sowohl an einer Spastik, als auch an autonomer Dysregulation unter anderem in Form von entgleister Hypertonie, litten, zeigte sich, dass sich bei intrathekaler Baclofengabe sowohl die Spastik, als auch die Blutdrucksituation besserte. Diese Beobachtung gab Anlass zu einem Gemeinschaftsprojekt, in dem die Neurotransmitter bzw. deren Abbauprodukte Adrenalin, Noradrenalin, HVA, Dopac, 5-HT, Glutamat und Aspartat bestimmt wurden. Parallel wurde intraarteriell der Blutdruck gemessen. Ziel: In dieser Arbeit sollte der Zusammenhang zwischen intrathekaler Baclofenapplikation und Freisetzung von Adrenalin, Noradrenalin und Homovanillinsäure untersucht werden. Homovanillinsäure, als Abbauprodukt von Noradrenalin, Adrenalin und Dopamin wurden als Parameter für die Ausschüttung von Dopamin verwendet. Vom Nucleus paraventricularis hypothalami ist bekannt, dass er sowohl neuroendokrinologische Aufgaben übernimmt, als auch eine Rolle in der zentralen Regulation autonomer Funktion, unter anderen der Kontrolle des Blutdrucks spielt. Die erste Aufgabe wird dem magnozellulären Anteil, die zweite Aufgabe dem parvozellulären Anteil des Nucleus paraventricularis hypothalami zu geschrieben. Baclofen ist ein spezifischer GABA ? B ? Rezeptor Agonist. Methode: Zur Untersuchung implantierten wir eine Mikrodialysesonde in den Nucleus para-ventricularis hypothalami. Von den insgesamt 38 Tieren applizierten 1,5 mg Baclofen 19 Tieren der Verum ? und die entsprechende Menge Ringerlösung 19 Tieren der Kontrollgruppe intrathekal. Mit Hilfe der HPLC bestimmten wir gleichzeitig die für diese Studie relevanten Katecholamine Noradrenalin, Adrenalin und den Metaboliten HVA, als auch die Neurotransmitter bzw. deren Abbauprodukte Dopa, Dopamin, Dopac, 5-HT und 5-HIAA, sowie die Aninosäuren Aspartat und Glutamat im Mikrodialysat. Ergebnis: Es zeigte sich kein signifikanter Unterschied zwischen der Verum- und Kontrollgruppe bezüglich der Ausschüttung von Adrenalin und Noradrenalin aus dem Nucleus paraventricularis hypothalami. Für HVA kann eine signifikante Erhöhung der Werte in der Verum - im Vergleich zur Kontrollgruppe nachgewiesen werden und weisen somit auf eine Beeinflussung durch Baclofen hin. Daher kann nach dieser Studie die Ausgangshypothese lediglich für HVA widerlegt werden, für Adrenalin und Noradrenalin kann sie weder bestätigt noch widerlegt werden. Schlussfolgerung: Um eine Antwort über den Einfluss des Nucleus paraventricularis hypothalami in der zentralen Blutdruckregulation und seine Beeinflussung durch Baclofen auf die Ausschüttung u.a. von Adrenalin, Noradrenalin und HVA zu geben ist sind weitere Studien sicher erforderlich

Influence of passive leg movements on blood circulation on the tilt table in healthy adults

BACKGROUND: One problem in the mobilization of patients with neurological diseases, such as spinal cord injury, is the circulatory collapse that occurs while changing from supine to vertical position because of the missing venous pump due to paralyzed leg muscles. Therefore, a tilt table with integrated stepping device (tilt stepper) was developed, which allows passive stepping movements for performing locomotion training in an early state of rehabilitation. The aim of this pilot study was to investigate if passive stepping and cycling movements of the legs during tilt table training could stabilize blood circulation and prevent neurally-mediated syncope in healthy young adults. METHODS: In the first experiment, healthy subjects were tested on a traditional tilt table. Subjects who had a syncope or near-syncope in this condition underwent a second trial on the tilt stepper. In the second experiment, a group of healthy subjects was investigated on a traditional tilt table, the second group on the tilt ergometer, a device that allows cycling movements during tilt table training. We used the chi-square test to compare the occurrence of near-syncope/syncope in both groups (tilt table/tilt stepper and tilt table/tilt ergometer) and ANOVA to compare the blood pressure and heart rate between the groups at the four time intervals (supine, at 2 minutes, at 6 minutes and end of head-up tilt). RESULTS: Separate chi-square tests performed for each experiment showed significant differences in the occurrence of near syncope or syncope based on the device used. Comparison of the two groups (tilt stepper/ tilt table) in experiment one (ANOVA) showed that blood pressure was significantly higher at the end of head-up tilt on the tilt stepper and on the tilt table there was a greater increase in heart rate (2 minutes after head-up tilt). Comparison of the two groups (tilt ergometer/tilt table) in experiment 2 (ANOVA) showed that blood pressure was significantly higher on the tilt ergometer at the end of head-up tilt and on the tilt table the increase in heart rate was significantly larger (at 6 min and end of head-up tilt). CONCLUSIONS: Stabilization of blood circulation and prevention of benign syncope can be achieved by passive leg movement during a tilt table test in healthy adults

Nine hole peg test and transcranial magnetic stimulation: useful to evaluate dexterity of the hand and disease progression in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with involvement of the upper and lower motor neurons. Since the loss of fine motor skills is one of the earliest signs of ALS, the hypothesis was tested if the nine hole PEG test (NHPT) and transcranial magnet stimulation (TMS) with resting-motor threshold (RMT) could be useful in monitoring disease progression. Methods. We examined 28 ALS patients and 27 age-matched healthy controls. ALS patients and healthy controls underwent the nine hole peg test (NHPT) and TMS with RMT. Measurements in patients were repeated after three and six months. Results. At baseline, the median NHPT durations were 1,4-fold longer (p < 0.001), and TMS scores showed a significant 0.8-fold smaller score in ALS patients compared with healthy controls (p < 0.001). The comparison of three and six months versus baseline revealed significant differences for NHPT durations and ALSFRS-R in patients, whereas TMS scores did not significantly differ in the patients. Conclusion. NHPT seems to be a good tool to evaluate dexterity of the hand and the progression of the disease in ALS patients. TMS RMT to the hand muscles seems to be poorly qualified to evaluate the dexterity of the hand function and the course of the disease

Intraneural hemorrhage in traumatic oculomotor nerve palsy

Isolated traumatic oculomotor nerve palsy without internal ophthalmoplegia is a rare condition after closed head trauma. The nerve strain leads to intraneural edema with nerve swelling on T2-weighted magnetic resonance (MR) images and traumatic disruption of the blood peripheral nerve barrier with contrast enhancement on T1-weighted MR images. In this patient, susceptibility-weighted MR imaging allowed the direct visualization of the intraneural hemorrhage after suspected traumatic diffuse neuronal axonal injury

In-vivo evaluation of neuronal and glial changes in amyotrophic lateral sclerosis with diffusion tensor spectroscopy

Diffusion tensor spectroscopy (DTS) combines features of magnetic resonance spectroscopy and diffusion tensor imaging and permits evaluating cell-type specific properties of microstructure by probing the diffusion of intracellular metabolites. This exploratory study investigates for the first time microstructural changes in the neuronal and glial compartments of the brain of patients with amyotrophic lateral sclerosis (ALS) using DTS. To this end, the diffusion properties of the neuronal metabolite tNAA (N-acetylaspartate + N-acetylaspartylglutamate) and the predominantly glial metabolites tCr (creatine + phosphocreatine) and tCho (choline-containing compounds) were evaluated in the primary motor cortex of 24 ALS patients and 27 healthy controls. Significantly increased values in the diffusivities of all three metabolites were found in ALS patients relative to controls. Further analysis revealed more pronounced microstructural alterations in ALS patients with limb onset than with bulbar onset relative to controls. This observation may be related to the fact that the spectroscopic voxel was positioned in the part of the motor cortex where the motor functions of the limbs are represented. The higher diffusivities of tNAA may reflect neuronal damage and/or may be a consequence of mitochondrial dysfunction in ALS. Increased diffusivities of tCr and tCho are in line with reactive microglia and astrocytes surrounding degenerating motor neurons in the primary motor cortex of ALS patients. This pilot study demonstrates for the first time that cell-type specific microstructural alterations in the brain of ALS patients may be explored in vivo and non-invasively with DTS. In conjunction with other microstructural magnetic resonance imaging techniques, DTS may provide further insights into the pathogenic mechanisms that underlie neurodegeneration in ALS. Keywords: Amyotrophic lateral sclerosis, Neurodegeneration, Diffusion-weighted spectroscopy, Tissue microstructure, Intracellular metabolite

Investigation of Neurodegenerative Processes in Amyotrophic Lateral Sclerosis Using White Matter Fiber Density

In the current work two novel parameters, fiber density (FD) and mean diffusion signal (MDS) are investigated for evaluating neurodegenerative processes in amyotrophic lateral sclerosis (ALS). The MDS provides a measure of the FD but is derived directly from the diffusion signal. Using tract-based spatial statistics (TBSS), pathological changes across the entire white matter and changes in the parameters over time were evaluated. The results were related to those obtained using the fractional anisotropy (FA) value. A widespread pattern of significantly decreased FD and MDS values was observed. A strong trend towards statistical significance was seen in similar white matter structures using TBSS analysis based on the FA value. Longitudinal analysis of the FD values demonstrated continuing deterioration of the same fiber tracts that were shown to be impaired in the group analysis. The findings suggest that MDS and in particular FD show great promise for evaluating microstructural white matter changes in ALS and may be more sensitive than the more commonly used FA value

Suction/Inspiration against resistance or standardized Mueller maneuver: a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

Objective: Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. Material and methods: The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Results: Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Conclusion: Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. Key Points : • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers

Spiral gradient echo versus cartesian turbo spin echo imaging for sagittal contrast-enhanced fat-suppressed T1 weighted spine MRI:an inter-individual comparison study

OBJECTIVES: To compare a novel 3D spiral gradient echo (GRE) sequence with a conventional 2D cartesian turbo spin echo (TSE) sequence for sagittal contrast-enhanced (CE) fat-suppressed (FS) T1 weighted (T1W) spine MRI. METHODS: In this inter-individual comparison study, 128 patients prospectively underwent sagittal CE FS T1W spine MRI with either a 2D cartesian TSE ("TSE", 285 s, 64 patients) or a 3D spiral GRE sequence ("Spiral", 93 s, 64 patients). Between both groups, patients were matched in terms of anatomical region (cervical/thoracic/lumbar spine and sacrum). Three readers used 4-point Likert scales to assess images qualitatively in terms of overall image quality, presence of artifacts, spinal cord visualization, lesion conspicuity and quality of fat suppression. RESULTS: Spiral achieved a 67.4% scan time reduction compared to TSE. Interreader agreement was high (alpha=0.868-1). Overall image quality (4;[3,4] vs 3;[3,4], p<0.001 - p=0.002 for all readers), presence of artifacts (4;[3,4] vs 3;[3,4] p=0.027 - p=0.046 for all readers), spinal cord visualization (4;[4,4] vs 4;[3,4], p<0.001 for all readers), lesion conspicuity (4;[4,4] vs 4;[4,4], p=0.016 for all readers) and quality of fat suppression (4;[4,4] vs 4;[4,4], p=0.027 - p=0.033 for all readers), were all deemed significantly improved by all three readers on Spiral images as compared to TSE images. CONCLUSION: We demonstrate the feasibility of a novel 3D spiral GRE sequence for improved and rapid sagittal CE FS T1W spine MRI. ADVANCES IN KNOWLEDGE: A 3D spiral GRE sequence allows for improved sagittal CE FS T1W spine MRI at very short scan times