Über Subarachnoidal-Blutungen

Zusammenfassung Es gibt zahlreiche Ursachen der Subarachnoidalblutungen. Naturgemäß müssen dieselben in Gefäßveränderungen gesucht werden.Eine sog. idiopathische, spontane, essentielle Blutung haben viele Autoren (insbesondereHess) dadurch begründet, daß jede erkennbare Gefäßveränderung oder sonstige äußere Beeinflussung in einer großen Anzahl von Fällen, besonders bei Jugendlichen, nicht nachgewiesen werden kann. Diese Fälle wurden mit einer angioneurotischen Diathese begründet.Sicher gibt es derartige Fälle; jedoch ist diese Krankheitsform mit großer Vorsicht und Kritik zu bewerten, da verborgene Ursachen verschiedener Art, besonders das Basalaneurysma, vorhanden sein können.D. 8.     

Radiation exposures of cancer patients from medical X-rays: how relevant are they for individual patients and population exposure?

X-ray procedures have a substantial impact not only on patient care but also on man-made radiation exposure. Since a reliable risk-benefit analysis of medical X-rays can only be performed for diagnosis-related groups of patients, we determined specific exposure data for patients with the ten most common types of cancer. For all patients with the considered cancers undergoing medical X-ray procedures in a maximum-care hospital between 2000 and 2005, patient- and examination-specific data were retrieved from the hospital/radiology information system. From this data, the cumulative 5-year effective dose was estimated for each patient as well as the mean annual effective dose per patient and the mean patient observation time for each cancer site. In total, 151,439 radiographic, fluoroscopic, and CT procedures, carried out in 15,866 cancer patients (age, 62 ± 13 years), were evaluated. The mean 5-year cumulative dose varied between 8.6 mSv (prostate cancer) and 68.8 mSv (pancreas cancer). Due to an increasing use of CT scans, the mean annual effective dose per patient increased from 13.6 to 18.2 mSv during the 6-year period. Combining the results obtained in this study for a particular hospital with cancer incidence data for Germany, we estimated that cancer patients having X-ray studies constitute at least 1% of the population but receive more than 10% of the total effective dose related to all medical X-ray procedures performed nationwide per year. A large fraction of this dose is radiobiologically ineffective due to the reduced life expectancy of cancer patients.     

Functional cerebral asymmetries during the menstrual cycle: a cross-sectional and longitudinal analysis

This study aims at answering two basic questions regarding the mechanisms with which hormones modulate functional cerebral asymmetries. Which steroids or gonadotropins fluctuating during the menstrual cycle affect perceptual asymmetries? Can these effects be demonstrated in a cross-sectional (follicular and midluteal cycle phases analyzed) and a longitudinal design, in which the continuous hormone and asymmetry fluctuations were measured over a time course of 6 weeks? To answer these questions, 12 spontaneously cycling right-handed women participated in an experiment in which their levels of progesterone, estradiol, testosterone, LH, and FSH were assessed every 3 days by blood-sample based radioimmunoassays (RIAs). At the same points in time their asymmetries were analyzed with visual half-field (VHF) techniques using a lexical decision, a figure recognition, and a face discrimination task. Both cross-sectional and longitudinal analyzes showed that an increase of progesterone is related to a reduction in asymmetries in a figure recognition task by increasing the performance of the left-hemisphere which is less specialized for this task. Cross-sectionally, estradiol was shown to have significant relationships to the accuracy and the response speed of both hemispheres. However, since these effects were in the same direction, asymmetry was not affected. This was not the case in the longitudinal design, where estradiol affected the asymmetry in the lexical decision and the figural comparison task. Overall, these data show that hormonal fluctuations within the menstrual cycle have important impacts on functional cerebral asymmetries. The effect of progesterone was highly reliable and could be shown in both analysis schemes. By contrast, estradiol mainly, but not exclusively, affected both hemispheres in the same direction.     

Depression in Alzheimer's disease: is there a temporal relationship between the onset of depression and the onset of dementia?

Alzheimer's disease (AD) patients often present with concurrent major depression (MD). To investigate the reasons for this comorbidity, e.g. MD being a risk factor for AD, or both diagnoses having a common neurobiology, the temporal relationship between the first onset of AD and of MD during lifetime was investigated-57 out of 146 AD patients had a lifetime diagnosis of MD. The correlation between the ages at onset of MD and dementia was calculated. The incidence of MD in AD patients in several 5-year-intervals before and after the onset of AD was compared with the average incidence of MD in the present AD sample and with the expected incidence of MD in the general population. No significant correlation between the onset of AD and of MD could be found after controlling for age, gender and the Mini-Mental-State. However, the incidence of MD 5 years before and after the onset of AD significantly exceeded the expected incidences-MD is only partially related to AD. However, the increased incidence of MD within 5 years before and after the onset of dementia may indicate that a common neurobiological process causes cognitive decline and depression in a subsample of AD patients.     

Longitudinal study of myelin basic protein-specific T-cell receptors during the course of multiple sclerosis

This study analyzed the stability of the myelin basic protein (MBP)-specific T-cell receptor (TCR) repertoire during the course of multiple sclerosis (MS) in three patients who were monitored for three years by gadolinium-enhanced magnetic resonance imaging. Bulk-culture T-cell lines (TCLs) were generated from 3–4 time points for each patient, including times of active and quiescent disease. TCR analysis of these TCLs indicated that both the Vα and Vβ usage was similar over time for each patient. Sequencing of TCRs demonstrated conserved complementarity-determining region 3 (CDR3) sequences within TCLs that expressed the same Vα segment over time, although the Jα usage was different for each TCR. This indicates that the population of MBP-reactive T-cells is changing during the course of MS, but that host and/or environmental factors may be selecting T-cells with particular MHC/peptide binding domains.     

Protection with estradiol in developmental models of apoptotic neurodegeneration

Medical measures that bear no known danger for the adult brain may trigger active neuronal death in the developing brain. Pharmacological blockade of N-methyl-D-aspartate or activation of GABA(A) receptors, blockade of voltage-dependent sodium channels, and oxygen induce widespread apoptotic neurodegeneration during the period of rapid brain growth in rodents. Because such measures are often necessary in critically ill infants and toddlers, search for adjunctive neuroprotective strategies is warranted. We report that 17beta-estradiol ameliorates neurotoxicity of drugs that block N-methyl-D-aspartate receptors, activate GABA(A) receptors, or block voltage-gated sodium channels and reduces neurotoxicity of oxygen in the infant rat brain. This neuroprotective effect is reversed by tamoxifen and cannot be reproduced by 17alpha-estradiol. 17Beta-estradiol did not affect GABA(A) or N-methyl-D-aspartate currents in hippocampal neuronal cultures, indicating that direct modulation of neurotransmitter receptor/channel properties by this compound cannot explain neuroprotective effect. 17beta-Estradiol did, however, increase levels of phosphorylated extracellular signal-regulated kinase 1/2 and AKT, suggesting that activation of these prosurvival proteins may represent one mechanism for its neuroprotective action. 17Beta-estradiol and related compounds may be neuroprotective agents suitable for use in critically ill infants and toddlers. Its supplementation may particularly help to improve neurocognitive outcome in preterm infants who are prematurely deprived of maternal estrogen.     

Retrograde Horseradish Peroxidase Transport in Motor Axons after Nd:YAG Laser Irradiation of the Tibial Nerve in Rats

We have recently demonstrated that the number of small sensory neurons of the A-δ- and C-fiber group in lumbar dorsal root ganglia labeled with horseradish peroxidase (HRP) is selectively decreased 7 days after Nd:YAG laser irradiation of the tibial nerve in the rat. In contrast, the number of large diameter sensory neurons was not affected by laser application. In an attempt to clarify the fate of motoneurons after laser irradiation of their peripheral axons, the numbers of lumbar motoneurons retrogradely labeled with HRP 7 days after Nd:YAG laser irradiation of the tibial nerve have been determined in rats. Our results show that the number of HRP-labeled motoneurons in lumbar segments L6 to L3 is not altered to a significant extent after laser irradiation of their peripheral axons (laser-treated side, 767 ± 10 cells vs control side, 808 ± 19; n = 5, mean ± SEM). In addition, no difference was detected in the mean value or the distribution of soma cross-sectional areas of labeled motoneurons on the laser-treated side and the control side. Specifically, the numbers of HRP-labeled small diameter motoneurons, which are presumably γ in type and have a conduction velocity similar to sensory neurons of the A-δ group, were not affected by laser application. Possible mechanisms of the differential vulnerability of sensory neurons as compared to motoneurons of similar size are discussed.     

Neuronal damage after moderate hypoxia and erythropoietin

Both mild hypoxia and exogenous erythropoietin may protect the brain against subsequent severe hypoxia, and the conditioning effect of transient hypoxia is partly mediated by hypoxia-induced endogenous erythropoietin. We now observed in several experimental models that combining transient hypoxia and exogenous erythropoietin may cause neuronal damage. High-dose erythropoietin (40 IU/ml) profoundly impeded synaptic transmission of rat hippocampal slice cultures when used in conjunction with moderate hypoxia (10% O2 for two 8-h periods). Addition of erythropoietin increased viability of cultured rat embryonic cortical neurons at 21% O2 but decreased viability under hypoxic conditions (2% O2) in a dose-dependent fashion. Death of human neuronal precursor cells challenged by oxygen and glucose deprivation was increased by erythropoietin when cells were cultured under hypoxic but not under normoxic conditions. In neonatal rats exposed to moderate hypoxia plus erythropoietin, numbers of degenerating cerebral neurons were increased, as compared to controls or rats subjected to either hypoxia or erythropoietin alone. Thus, erythropoietin may aggravate rather than ameliorate neuronal damage when administered during transient hypoxia.     

Mentholsubstitution als Option zur Dosisreduktion von Urso- und Chenodeoxychols?ure in der adjuvanten Therapie nach ESWL von Gallenblasensteinen

Zusammenfassung. Hintergrund:   Die litholytische Aktivität von Terpenen wird in der konservativen Therapie des Gallensteinleidens unterschiedlich beurteilt. Die Steinfreiheit durch Lyse von Restfragmenten ist ein geeignetes Modell zur Überprüfung der litholytischen Aktivität von Menthol. Patienten und Methodik:   Nach extrakorporaler Stoßwellenlithotripsie (ESWL) bei symptomatischen Gallenblasensteinträgern wurde die Litholyseeffektivität zwischen der Standardtherapie aus jeweils 125 mg Urso-/Chenodeoxycholsäure (UDC/CDC) pro 25 kg Körpergewicht (UDC + CDC) und jeweils 62,5 mg UDC/CDC plus 125 mg Menthol (M) pro 25 kg Körpergewicht (M + UDC + CDC) verglichen. 70 Patienten wurden doppelblind mit M + UDC + CDC (n = 36) oder UDC + CDC (n = 34) behandelt. Ergebnisse:   19 von 34 Patienten (55,9%) der UDC + CDC-Gruppe wurden in einem durchschnittlichen Zeitraum von 5,9 Monaten steinfrei, gegenüber 17 von 36 Patienten (47,2%) der M + UDC + CDC-Gruppe in 8,8 Monaten. Unter UDC + CDC waren die Patienten insgesamt signifikant schneller (p = max [p1,p2] = 0,4717) steinfrei als unter M + UDC + CDC. Nach Abzug der vorzeitig aus der Studie ausgeschiedenen Patienten fand sich zu den Kontrollzeitpunkten nach 9 und 12 Monaten mit 16 : 9 bzw. 19 : 12 eine signifikant größere Anzahl fragmentfreier Patienten, während zu den übrigen Kontrollzeitpunkten kein signifikanter Unterschied nachzuweisen war. Vor ESWL hatten sieben von 25 Patienten in der Mentholgruppe zwei oder mehr Steine, während dies in der Gruppe mit der Standardtherapie nur auf zwei Patienten zutraf. Fünf Patienten wiesen bei Eintritt in die Studie eine leichte Kalzifikation auf, vier davon erhielten M + UDC + CDC. Schlussfolgerung:   Unter der Standardtherapie UDC + CDC werden die Patienten zwar insgesamt schneller steinfrei; nach Abzug der vorzeitig ausgeschiedenen Patienten resultiert dies jedoch aus signifikant größeren Steinfreiheitsraten zu den Kontrollzeitpunkten nach 9 und 12 Monaten, so dass sich insgesamt—auch eingedenk der schlechteren Steinparameter in der Mentholgruppe—kein statistisch signifikanter, relevanter Unterschied in der Effektivität der beiden Therapieregime ergibt.