The quantitative effect of antimicrobial usage in Danish pig farms on the abundance of antimicrobial resistance genes in slaughter pigs.

Research has long established the connection between antimicrobial use (AMU) and antimicrobial resistance (AMR) in production animals, and shown that the ceasing of AMU reduces AMR. Our previous study of Danish slaughter-pig production found a quantitative relationship between lifetime AMU and abundance of antimicrobial resistance genes (ARGs). This study aimed to generate further quantitative knowledge on how changes in AMU in farms influence the abundance of ARGs both with immediate effect and over time. The study included 83 farms that were visited from 1 to 5 times. From each visit, a pooled faecal sample was produced. The abundance of ARGs was obtained by metagenomics. We used two-level linear mixed models for estimating the effect of AMU on the abundance of ARGs against six antimicrobial classes. The lifetime AMU of each batch was calculated from usage during their three rearing periods; as piglets, weaners and slaughter pigs (rearing pathway). AMU at farm level was estimated as the mean lifetime AMU of the sampled batches from each farm. At batch level, AMU was measured as the deviation between the batch-specific lifetime AMU and the general mean lifetime AMU at the farm. For peroral tetracycline and macrolide use there was a significant quantitative linear effect on the abundance of ARGs in batches within individual farms, indicating an immediate effect of changed AMU from batch to batch within farms. These estimated effects between batches within farms were approximately 1/2-1/3 of the effect estimated between farms. For all antimicrobial classes, the effect of the mean farm-level AMU and the abundance of ARGs present in the faeces of slaughter pigs was significant. This effect was identified only for peroral use, except for lincosamides, where the effect was for parenteral use. The results also indicated that the abundance of ARGs against a specific antimicrobial class also increased by the peroral usage of one or several other antimicrobial classes, except for ARGs against beta-lactams. These effects were generally lower than the AMU effect of the specific antimicrobial class. Overall, the farm peroral mean lifetime AMU affected the abundance of ARGs at antimicrobial class level and abundance of ARGs of other classes. However, the difference of AMU of the slaughter-pig batches affected only the abundance of ARGs at the same antimicrobial class level in the same antimicrobial class. The results do not exclude that parenteral usage of antimicrobials may have an effect on the abundance of ARGs.

Chronic, acute and protocol-dependent effects of exercise on psycho-physiological health during long-term isolation and confinement.

Exercise could prevent physical and psychological deteriorations, especially during pandemic times of lock-down scenarios and social isolation. But to meet both, the common exercise protocols require optimization based on holistic investigations and with respect to underlying processes. This study aimed to explore individual chronic and acute effects of continuous and interval running exercise on physical and cognitive performance, mood, and affect and underlying neurophysiological factors during a terrestrial simulated space mission. Six volunteers (three females) were isolated for 120 days. Accompanying exercise training consisted of a continuous and interval running protocol in a cross-over design. Incremental stage tests on a treadmill were done frequently to test physical performance. Actigraphy was used to monitor physical activity level. Cognitive performance, mood (MoodMeter®), affect (PANAS), brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), vascular-endothelial growth factor (VEGF), and saliva cortisol were investigated prior to, four times during, and after isolation, pre- and post-exercise on two separate days, respectively. As a chronic effect, physical performance increased (and IGF-1 tended) in the course of isolation and training until the end of isolation. Subjective mood and affect state, as well as cognitive performance, basal BDNF and VEGF levels, were well-preserved across the intervention. No acute effects of exercise were detected, besides slower reaction time after exercise in two out of nine cognitive tests, testing sensorimotor speed and memory of complex figures. Consistently higher basal IGF-1 concentrations and faster reaction time in the psychomotor vigilance test were found for the continuous compared to the interval running protocol. The results suggest that 120 days of isolation and confinement can be undergone without cognitive and mental deteriorations. Regular, individual aerobic running training supporting physical fitness is hypothesized to play an important role in this regard. Continuous running exercise seems to trigger higher IGF-1 levels and vigilance compared to interval running. Systematic and prolonged investigations and larger sample size are required to follow up on exercise-protocol specific differences in order to optimize the exercise intervention for long-term psycho-physiological health and well-being.

Influence of pedestal diameter on mode instabilities in Yb/Ce/Al-doped fibers.

In this paper we present numerical and experimental results revealing that the mode instability threshold of highly Yb-doped, Ce/Al co-doped pedestal fibers is affected by the size of the index-increased pedestal structure surrounding the core. An alternative preparation technology for the realization of large mode area fibers with very large Al-doped silica pedestals is introduced. Three different pedestal fiber design iterations characterized by low photodarkening were manufactured and tested in counter-pumped amplifier setups. Up to 1.9 kW continuous-wave output power of near-diffraction-limited beam quality (M2 = 1.26) was achieved with an 18/200/420 µm fiber of very low NA = 0.042, limited only by the occurrence of mode instabilities.

Uso de bastones contralaterales en artrosis de rodilla / Contralateral canes for knee osteoarthritis

INTRODUCCIÓN La artrosis de rodilla es un problema de salud relevante dada su alta prevalencia y discapacidad asociada. Dentro de las alternativas de manejo no farmacológico se ha planteado el uso de bastones, sin embargo no existe consenso en la literatura respecto a su indicación. MÉTODOS Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis, preparamos tablas de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES Identificamos tres revisiones sistemáticas que en conjunto incluyeron cuatro estudios primarios, de los cuales, uno es ensayo aleatorizado. Concluimos que el uso de bastón contralateral en pacientes con artrosis de rodilla probablemente disminuye el dolor. Además, podría aumentar levemente la funcionalidad, pero la certeza de la evidencia es baja.

INTRODUCTION Knee osteoarthritis is a relevant health problem given its high prevalence and associated disability. Within the non-pharmacological management alternatives, the use of canes has been proposed, however, there is no consensus in the literature regarding its indication. METHODS We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS We identified three systematic reviews including four studies overall, of which one was randomized trials. We conclude that the use of a contralateral cane in patients with knee osteoarthritis probably reduces pain. In addition, it could slightly increase function, but the certainty of the evidence is low.

Application of open-path Fourier transform infrared spectroscopy for atmospheric monitoring of a CO2 back-production experiment at the Ketzin pilot site (Germany).

During a controlled "back-production experiment" in October 2014 at the Ketzin pilot site, formerly injected CO2 was retrieved from the storage formation and directly released to the atmosphere via a vent-off stack. Open-path Fourier transform infrared (OP FTIR) spectrometers, on-site meteorological parameter acquisition systems, and distributed CO2 point sensors monitored gas dispersion processes in the near-surface part of the atmospheric boundary layer. The test site provides a complex and challenging mosaic-like surface setting for atmospheric monitoring which can also be found at other storage sites. The main aims of the atmospheric monitoring of this experiment were (1) to quantify temporal and spatial variations in atmospheric CO2 concentrations around the emitting vent-off stack and (2) to test if and how atmospheric monitoring can cope with typical environmental and operational challenges. A low environmental risk was encountered during the whole CO2 back-production experiment. The study confirms that turbulent wind conditions favor atmospheric mixing processes and are responsible for rapid dilution of the released CO2 leading to decreased detectability at all sensors. In contrast, calm and extremely stable wind conditions (especially occurring during the night) caused an accumulation of gases in the near-ground atmospheric layer with the highest amplitudes in measured gas concentration. As an important benefit of OP FTIR spectroscopic measurements and their ability to detect multiple gas species simultaneously, emission sources could be identified to a much higher certainty. Moreover, even simulation models using simplified assumptions help to find suitable monitoring network designs and support data analysis for certain wind conditions in such a complex environment.

Targeted gene sequencing and whole-exome sequencing in autopsied fetuses with prenatally diagnosed kidney anomalies.

Identification of fetal kidney anomalies invites questions about underlying causes and recurrence risk in future pregnancies. We therefore investigated the diagnostic yield of next-generation sequencing in fetuses with bilateral kidney anomalies and the correlation between disrupted genes and fetal phenotypes. Fetuses with bilateral kidney anomalies were screened using an in-house-designed kidney-gene panel. In families where candidate variants were not identified, whole-exome sequencing was performed. Genes uncovered by this analysis were added to our kidney panel. We identified likely deleterious variants in 11 of 56 (20%) families. The kidney-gene analysis revealed likely deleterious variants in known kidney developmental genes in 6 fetuses and TMEM67 variants in 2 unrelated fetuses. Kidney histology was similar in the latter 2 fetuses-presenting a distinct prenatal form of nephronophthisis. Exome sequencing identified ROBO1 variants in one family and a GREB1L variant in another family. GREB1L and ROBO1 were added to our kidney-gene panel and additional variants were identified. Next-generation sequencing substantially contributes to identifying causes of fetal kidney anomalies. Genetic causes may be supported by histological examination of the kidneys. This is the first time that SLIT-ROBO signaling is implicated in human bilateral kidney agenesis.

Modulation of the CO2 fixation in dinickel azacryptands.

While bimetallic azacryptands are known to selectively coordinate CO2, there is little knowledge on how different substitution patterns of the azacryptand cage structure influence CO2 coordination. Stopped-flow UV-vis spectroscopy, electrochemical analysis and DFT calculations were performed on a series of dinickel azacryptands and showed different rates of CO2 coordination to the complexes. We herein present data showing that the different flexibility of the azacryptands is directly responsible for the difference in the CO2 uptake capability of dinickel azacryptand complexes.

Fixation stability and implication for multifocal electroretinography in patients with neovascular age-related macular degeneration after anti-VEGF treatment.

PURPOSE: To quantify fixation stability in patients with neovascular age-related macular degeneration (nAMD) at baseline, 3 and 6 months after anti-vascular endothelial growth factor (anti-VEGF) treatment and furthermore asses the implications of an unsteady fixation for multifocal electroretinography (mfERG) measurements. METHODS: Fifty eyes of 50 nAMD patients receiving intravitreal anti-VEGF treatment with either bevacizumab or ranibizumab and eight eyes of eight control subjects were included. Fixation stability measurements were performed with the Eye-Link eyetracking system and the retinal area in degrees2 (deg2) containing the 68 % most frequently used fixation points (RAF68) was calculated. MfERG P1 amplitude and implicit time were analyzed in six concentric rings and as a summed response. Patients were examined at baseline, 3 and 6 months. Four different mfERG recordings were performed for the control subjects to mimic an involuntary unstable fixation: normal central fixation, 2.4°, 4.8°, and 7.1° fixation instability. RESULTS: For control subjects, a fixation instability of 2.4° (corresponding to the central hexagon) did not reduce mfERG ring amplitudes significantly, whereas 4.8° and 7.1° fixation instability reduced the amplitudes significantly in rings 1 and 2 (p < 0.001) as well as in the peripheral rings in the 7.1° instability condition (p < 0.001). Fixation stability improved non-significantly for patients at 3 and 6 months. The size of the retinal area of fixation was at baseline, 3 and 6 months negatively correlated to visual acuity (VA) (rbaseline = -0.65, r3 months = -0.60, and r6 months = -0.66 respectively, p < 0.001) and mfERG amplitudes of the three innermost rings (rbaseline = -0.29, p = 0.042, r3 months = -0.43, p = 0.003 and r6 months = -0.31, p = 0.042). The VA cutoff for a fixation area less than 5 deg2 (approximately the central hexagon) was 65, 77, and 68 ETDRS letters (corresponding a maximal Snellen equivalent of 0.31) at baseline, 3 and 6 months, respectively. CONCLUSIONS: MfERG amplitudes in recordings of nAMD patients are at substantial risk of being reduced due to poor fixation as a large number of patients may use a fixation area of more than 5 deg2. Fixation monitoring during recording as well as interpretation of results should be performed with care, especially in patients with poor visual acuity.

Bimetallic nickel complexes for selective CO2 carbon capture and sequestration.

Herein we report a dinickel azacryptand complex that enables fast, selective, and tight CO2 binding from air. Exploiting the affinity of the cavitand towards azides, CO2 release was observed. Despite the stability of the azido complex, UV irradiation under atmospheric conditions proved to be a suitable pathway for N3(-) replacement by CO2.

Fluorescence enhancement at docking sites of DNA-directed self-assembled nanoantennas.

We introduce self-assembled nanoantennas to enhance the fluorescence intensity in a plasmonic hotspot of zeptoliter volume. The nanoantennas are prepared by attaching one or two gold nanoparticles (NPs) to DNA origami structures, which also incorporated docking sites for a single fluorescent dye next to one NP or in the gap between two NPs. We measured the dependence of the fluorescence enhancement on NP size and number and compare it to numerical simulations. A maximum of 117-fold fluorescence enhancement was obtained for a dye molecule positioned in the 23-nanometer gap between 100-nanometer gold NPs. Direct visualization of the binding and unbinding of short DNA strands, as well as the conformational dynamics of a DNA Holliday junction in the hotspot of the nanoantenna, show the compatibility with single-molecule assays.

Diabetic nephropathy but not HbA1c is predictive for frequent complications of Charcot feet - long-term follow-up of 164 consecutive patients with 195 acute Charcot feet.

AIMS: To investigate the clinical characteristics, treatment and long-term outcome of patients with acute Charcot feet (CF). METHODS: Single-center retrospective analysis. Treatment of CF: stage-dependent immobilization/weight-off therapy, orthopaedic/adjusted shoes, foot surgery. 164 consecutive participants (type 1 vs. type 2 diabetes): 12 vs. 150, non-diabetic peripheral neuropathy: n=2, presented with 195 (17 vs. 176) CF. Mean follow-up: 4.7 ± 2.5 (range 2.2-9.8) vs. 5.4 ± 2.9 (range 0.8-18.8) years, vital at follow-up: 100 vs. 88%. RESULTS: Baseline characteristics: age: 43.7 ± 10.9 vs. 57.9 ± 8.9 years (p<0.001), male gender: 66.7 vs. 77.3%, diabetes duration: 19.2 ± 9.1 vs. 13 ± 8.6 years (p=0.018), GHb: 8.1 ± 2.4 vs. 7.6 ± 1.6%, BMI: 24 ± 5.3 vs. 33.7 ± 6.5 kg/m2 (p<0.001), Levine 1: 18.2 vs. 7.4%, Levine 2: 45.5 vs. 65.9%, Sanders 2: 58.3 vs. 68.5%, Sanders 3: 33.3 vs. 45%. THERAPY: immobilization for 6 ± 4.2 vs. 5.4 ± 4.5 months, orthopaedic/adjusted shoes: 27.3 vs. 20.5%, foot surgery: 11.8 vs. 18.2%. Major complications: 50 vs. 56% (rocker bottom deformities: 23.5 vs. 46.3%, foot ulcerations: 17.6 vs. 24.6%, CF amputations: 0 vs. 6%), not CF amputations: 16.7 vs. 15.3%, second episodes of CF: 41.6 vs. 18.3% after 5-132 months. Diabetic nephropathy was associated with an increase, intensive antihypertensive therapy with a decrease of complications. CONCLUSIONS: Patients with CF are middle-aged, overweight males with type 2 diabetes above 10 years. Patients with type 1 diabetes are younger, have normal BMI and longer diabetes duration. Major complications and second episodes of CF are frequent. Diabetic nephropathy could be a risk factor for CF related complications. The awareness for CF must be improved.The study was conducted due to the Declaration of Helsinki.

HAGIL (Hamburg Vigil Study): a randomized placebo-controlled double-blind study with modafinil for treatment of fatigue in patients with multiple sclerosis.

OBJECTIVE: To reassess the effect of modafinil, a wakefulness-promoting artificial psychostimulant, on fatigue and neuropsychological measures in patients with multiple sclerosis. METHODS: Multiple sclerosis (MS) patients with a baseline score of ≥4 on the Fatigue Severity Scale (FSS) and an Expanded Disability Status Scale score <7 were eligible for the 8-week randomized, double-blind, placebo-controlled study. Modafinil was dosed up to 200 mg/day within 1 week. Assessments were performed at baseline and after 4 and 8 weeks. The primary outcome parameter was the mean change of the FSS mean score. Secondary outcome variables were other questionnaires covering fatigue, daytime sleepiness and sleep quality. Cognitive impairment was assessed by the oral version of the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT). RESULTS: The study included 121 MS patients. Dropout rate was 9%. Both treatment groups showed improvements through time. While mean FSS at 8 weeks showed a trend difference between groups in the intention-to-treat analysis, the primary endpoint was not met. Assessment of cognitive impairment by SDMT and PASAT showed contradictory results. All other secondary endpoints were not met. There was no major safety concern. CONCLUSIONS: In general, the study does not support modafinil as an effective treatment for MS fatigue. However, the study shows the need for new study designs and endpoints in MS fatigue studies.

A ferric chloride induced arterial injury model used as haemostatic effect model.

A number of experimental bleeding models have been applied to animal models of haemophilia in order to evaluate the acute haemostatic effect of procoagulant compounds. In contrast, in vivo thrombosis models (including the FeCl(3) induced injury model) have mainly been used to study antithrombotic pharmacological intervention. However, as there are limitations to existing bleeding models and as new recombinant FVIII, FIX, and FVIIa variants with increased and prolonged activity are generated there is an increasing need for new and optimized in vivo animal models for testing the efficacy of these haemostatic drug candidates. This led us to look at existing thrombosis models in a new perspective. We have studied the effect of a FeCl(3) induced arterial injury in both F8-KO and F9-KO mice using optimized conditions where exposure to FeCl(3) induces occlusion within 4.2 +/- 0.2 min in wild type mice with a normal coagulation system. In contrast, no occlusion was observed in haemophilic mice providing a therapeutic window in the model making it suitable for pharmacological testing of therapeutic intervention. We demonstrate that replacement therapy with a clinical relevant dose of rFVIII (Advate 20-80 U kg(-1)) and rFIX [(0.75 mg kg(-1) BeneFIX) approximately 50 IU kg(-1)] restored coagulation and normalized the time to occlusion following FeCl(3) induced injury in F8-KO mice and restored coagulation and nearly normalized the time to occlusion in F9-KO mice. In conclusion, we have demonstrated that under optimized conditions the FeCl(3) induced arterial injury model provides a therapeutic window that makes it an useful effect model for evaluation of the haemostatic potential of procoagulant drugs.

Increased performance of secondary clarifiers using dynamic distribution of minimum return sludge rates.

Most wastewater treatment plants have several secondary clarifiers or even more sets of clarifiers including several secondary clarifiers, and in practice it is a well known problem that equal distribution of the load to the single clarifier (or set of clarifiers) is very difficult-not to say impossible-to obtain. If the problem is neglected, quite a big percentage of the total clarifier capacity-measured as the max. allowed hydraulic load-can be lost. Further, return sludge rates are seldom controlled by any other means than as a (typically too high) percentage of the inlet to the wastewater treatment plant-giving a varying and too low suspended solids concentration in the return sludge, which again can lead to an unnecessary use of polymer in the pre-dewatering of the surplus sludge taken from the return sludge. A control of the return sludge rate divided into two parts - control of the total return sludge flow and control of how the total flow shall be distributed between the secondary clarifiers - is able to solve the mentioned problems. Finally, as shall be demonstrated on full scale wastewater treatment plants, a considerable increase of the hydraulic capacity of the treatment plants can be obtained.

Responses of estrogen sensitive tissues in female Wistar rats to pre- and postnatal isoflavone exposure.

Effects of isoflavones on estrogen sensitive tissues are discussed controversially. This study was designed to investigate tissue specific effects of an isoflavone exposure through different periods of life in female Wistar rats and to compare the effects of genistein (GEN) to those of mixed dietary isoflavones, GEN and daidzein (DAI). One group received an isoflavone-free diet (IDD), another was fed an isoflavone-rich diet (IRD) and the third group an IDD supplemented with GEN (GEN(d)) prior to mating, throughout pregnancy and up to weaning. The offspring were kept on the respective diets during growth, puberty and adulthood. The weight of the uterus, the height of the uterine and vaginal epithelium, the bone mineral density of the tibia, and the expression of the estrogen sensitive gene CaBP9K in the liver were determined. At d21, the uterine weight, the uterine epithelium and the expression of CaBP9K in the liver were significantly stimulated in GEN(d) animals compared to IDD and IRD. Interestingly, bone mineral density was increased in GEN(d) and in IRD animals. Around puberty (d50) neither uterine wet weights nor trabecular bone density differed significantly among the isoflavone groups and the IDD control. At d80 no significant differences in uterine weight were observed among IDD, GEN(d) and IRD animals. However, bone mineral density was increased in GEN(d) and IRD animals. In summary, our results demonstrate that lifelong dietary exposure to isoflavones can affect estrogen sensitive tissues, apparently in a tissue selective manner. With respect to health risk and benefit our data indicate that an increased bone mineral density can be achieved by lifelong exposure to an IRD, which, in contrast to GEN supplementation, does not seem to stimulate the proliferation of the uterine epithelium.

A biomechanical evaluation of the relative load change in the joints of the wrist with ulnar shortening: a 'handbag' model.

The wrist joint is loaded not only while applying a proximally directed load but also, less obviously, while carrying a handbag. Ulnar shortening reduces pressure and relieves pain in the ulnocarpal joint. The present study evaluated the pressure distribution in the wrist joints with ulnar shortening and lengthening when applying traction to the flexed fingers while the fingers were loaded and unloaded. The compressive forces in the loaded wrist were distributed with 67% across the radiocarpal joint and 33% across the ulnocarpal joint. Shortening the ulna by 3 mm increased load in the radius to 80%. Lengthening of the ulna by 1 mm increased its load to 55%. The load share of the distal radioulnar joint was constant even when the ulna was shortened 3-4 mm. It seems advisable to shorten the ulna by 3 mm, since the increased load in the related joints are constant within a range of -2 to -4 mm.

Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study.

BACKGROUND: We use an intubating laryngeal mask (ILM) in preference to an endotracheal tube (ETT) as the ventilatory device during percutaneous dilatational tracheostomy (PDT) to overcome potential problems such as difficult ventilation, accidental extubation, damage of the ETT or of the bronchoscope, and need for additional assistant to secure the airway. We report our experience with this method. METHODS: In this prospective observational study, PDT was performed using the ILM in 86 patients. The insertion of the ILM, the quality of ventilation, and the view of the tracheal puncture site were rated as: 'very good', 'good', 'difficult', and 'not possible with ILM'. RESULTS: The bronchoscope was not damaged during any case, and all PDTs were performed by two physicians, without the need for an additional assistant. PDTs with ILM were successful in 95% of the patients (n=82). The ratings were 'very good' or 'good' in 80% of cases with regards to ventilation, in 90% for identification of relevant structures and tracheal puncture site, and in 85% for the view inside the trachea during PDT. Tracheal re-intubation was required for inadequate ventilation with ILM in four patients. CONCLUSIONS: The advantages of this procedure were lack of damage to the bronchoscope, the need for two instead of three persons to perform the PDT, and the excellent view inside the trachea. We recommend the ILM as a standard device for ventilation during bronchoscope-guided PDT.

Dynamic cerebral autoregulation in patients with ruptured and unruptured aneurysms after induction of general anesthesia.

INTRODUCTION: Blood pressure management in patients undergoing surgery for clipping of aneurysms is demanding. More information about the ability of cerebral vessels to normally regulate cerebral blood flow may have a direct influence on the intraoperative management. In patients with subarachnoid hemorrhage (SAH) a disturbance of cerebral autoregulation has been reported and it correlated with the severity of the bleeding in these studies. The impairment of autoregulation was demonstrated using static measurements of cerebral pressure autoregulation. However, the dynamic component of the autoregulatory capacity seems to be of importance in the acute setting after SAH. The aim of this study was to evaluate dynamic pressure autoregulation in patients undergoing surgery for intracranial aneurysms. PATIENTS/MATERIAL AND METHODS: 36 patients with a mean age of 45 years were evaluated, 26 patients with acute SAH, 10 patients with unruptured aneurysms. Cerebral autoregulation in normocapnia was tested using thigh cuffs to alter arterial blood pressure and continuous registration of the blood flow velocities with transcranial Doppler sonography. After the induction of general anesthesia under normocapnia the autoregulatory index (ARI) was calculated (values between 0-9). Patient groups were compared using Wilcoxon- and Spearman's rank test. RESULTS: The two patient groups were comparable with regard to gender, age, PaCO(2), blood flow velocities and blood pressure. In patients with SAH mean ARI was 3.1/3.3 (right/left side) compared to 4.7/4.6 (right/left side) in patients without SAH. The difference was statistically significant (Wilcoxon p = 0.0399). The degree of impairment of the autoregulatory capacity increased significantly (p = 0.006) with the severity of the SAH (Hunt&Hess and Fisher scale). CONCLUSION: Dynamic pressure autoregulation is impaired in patients after SAH compared to patients without SAH and correlates with the severity of the SAH. We propose that autoregulation should be measured in all patients with SAH or that an impaired autoregulation should be taken into account in patients with SAH undergoing surgery in the acute phase.

The contribution of microsaccades and drifts in the maintenance of binocular steady fixation.

BACKGROUND: The eye performs three types of eye movements during fixation: fast microsaccades are interrupted by slow drift movements, and tremor is superimposed on the drifts. The contribution of the microsaccades and drifts in maintaining fixation has been discussed since the late 1950s. Initially, microsaccades were thought to correct the misalignment from the optimal fixation locus induced by the drift movements, a theory still postulated in more recent work. The present study aimed to uncover to what extent each fixation movement contributes to maintain steady binocular fixation. METHOD: Binocular fixation during a 40-s fixation task was recorded using an infrared recording technique for ten normal test persons. Start and end point of each microsaccade and drift were superimposed on a fixation map, and the distance to the preferred retinal location of fixation (PRL) was measured. RESULTS: It was found that 32.6% of the microsaccades corrected the previous drift movement towards the PRL, whereas 53.1% of the drifts corrected the endpoint of the previous microsaccade towards the PRL. The overall mean post-microsaccadic and mean post-drift distance to the PRL for the ten normal test persons were 0.46 degrees and 0.41 degrees , respectively; the difference was not statistically significant. Interindividually, the mean post-microsaccadic distance to the PRL ranged between 0.21 degrees and 0.91 degrees and the mean post-drift distance to the PRL ranged between 0.20 degrees and 0.72 degrees . CONCLUSION: Neither the endpoints of the microsaccades nor the drifts bring the visual line to coincide with the centre of the PRL. Consequently, it must be the eye movements performed during the drifts ("slow control") that keep the visual line in the centre of the foveola.

Fixation topography in normal test persons.

BACKGROUND: The eye is moved so that the object of interest falls on the central fovea, where the spatial resolution is highest. In the present study we quantified eye movements of normal test persons during steady fixation and characterized the fixation using a 3D fixation plot (X horizontal eye position, Y vertical eye position, Z time in each eye position). METHOD: Fixation eye movements were quantified binocularly in ten normal test persons during a 40-s fixation task using an infrared recording technique. RESULTS: The fixation plot was characterized by a single preferred fixation locus in 17 eyes. One eye had two distinctly separated preferred fixation locations and in two eyes the configuration of fixation plot was flat with no single identifiable locus of fixation. The fixation plots were elliptical along the horizontal meridian in 9 eyes, elliptical along the vertical meridian in 8 eyes, and round in 3 eyes. The fixation area (RAF95) ranged between 1418 and 14182 arcmin(2), and a significant positive correlation was found between RAF95 and the mean microsaccadic amplitude (p<0.001). CONCLUSION: The fixation plots are often characterized by a single preferred fixation locus but may also be almost flat with no identifiable location of fixation. The individual fixations patterns resembles the cone density contour plots as found in histological studies, and it may be speculated, that the shape of the fixation plot is determined by the cone density topography.