UV irradiance effects on komodo dragon (Varanus komodoensis) vitamin D3, egg production, and behavior: A case study

Modifications to UV irradiance for indoor housed herpetofauna can affect behavior and physiology. Low ultraviolet B (UVB) irradiance can result in vitamin D3 deficiency resulting in calcium metabolism disorders including metabolic bone disease and immune suppression. High UVB can result in skin and eye issues, which can be severe enough to cause shock and death. Using tools available for the assessment of UV light, including Ferguson zones and the UV working tool designed by the British and Irish Association of Zoos and Aquaria, we redesigned lighting in our indoor komodo dragon (Varanus komodoensis) habitat to better suit the UV requirements of this species, while studying changes in behavior and physiology. We measured serum vitamin 25-hydroxy D3 values in one male and one female komodo dragon before and after they were housed in indoor and outdoor habitats. We also measured behavior changes in our male komodo as he moved from an outdoor habitat, to an indoor habitat with changing UV irradiance. Our female komodo showed a 98% increase in vitamin D3 values after being moved outdoors, and laid her first clutch of eggs. Our male dragon's vitamin D3 remained consistent 200 days after moving inside. He did show increased activity when higher UV irradiance was available. Importantly, we found the UV lamps we used stopped producing desired UV irradiance within 3.5 months of regular use. We suggest all animal care facilities develop UV monitoring programs to research output and longevity of UVB lamps used in indoor herpetofauna habitats.

Learning curves of robotic technology in an orthopedic teaching hospital

BACKGROUND

In recent years there has been an increasing implementation of robotic technology in arthroplasty. Due to the unclear data situation the aim of this study was to analyze the learning curve for robotic technology in residency training.

METHODS

After its introduction, the first 351 consecutive robotic knee replacements were prospectively included in the study. Surgical times, preoperative and postoperative radiographs, intraoperatively recorded alignment data and complications were analyzed. Satisfaction, revision, and referral rates were determined in a 90-day follow-up survey. Data from the last 350 navigated total knee arthroplasties were analyzed as a historical control group.

RESULTS

A learning curve of between 3 and 53 procedures was identified, depending on the surgeon, with further reductions in time measured even after 1 year of use. The operative times of the navigated technique were achieved by all surgeons. With respect to precision (alignment outliers) and patient satisfaction rate, no learning curve was evident. Comparison between tutorial and non-tutorial surgery showed a 16-min increase in operating time, but no significant differences in precision, complications, and patient satisfaction rate.

CONCLUSION

The study showed that there was a learning curve in terms of duration of surgery but not in terms of precision, complications, and patient satisfaction. Robotic tutorial surgery requires more time but provides the same outcome compared to experienced surgeons. Thus, the robotic surgical technique appears to be an excellent training tool in knee arthroplasty.

The Influence of Methylphenidate on Hyperactivity and Attention Deficits in Children With ADHD: A Virtual Classroom Test

Objective: This study compares the performance in a continuous performance test within a virtual reality classroom (CPT-VRC) between medicated children with ADHD, unmedicated children with ADHD, and healthy children. Method:N = 94 children with ADHD (n = 26 of them received methylphenidate and n = 68 were unmedicated) and n = 34 healthy children performed the CPT-VRC. Omission errors, reaction time/variability, commission errors, and body movements were assessed. Furthermore, ADHD questionnaires were administered and compared with the CPT-VRC measures. Results: The unmedicated ADHD group exhibited more omission errors and showed slower reaction times than the healthy group. Reaction time variability was higher in the unmedicated ADHD group compared with both the healthy and the medicated ADHD group. Omission errors and reaction time variability were associated with inattentiveness ratings of experimenters. Head movements were correlated with hyperactivity ratings of parents and experimenters. Conclusion: Virtual reality is a promising technology to assess ADHD symptoms in an ecologically valid environment.

Clinical Impact of Ventilation Duration in Patients with Stroke Undergoing Interventional Treatment under General Anesthesia: The Shorter the Better?

BACKGROUND AND PURPOSE

Whether general anesthesia for neurothrombectomy in patients with ischemic stroke has a negative impact on clinical outcome is currently under discussion. We investigated the impact of early extubation and ventilation duration in a cohort that underwent thrombectomy under general anesthesia.

MATERIALS AND METHODS

We analyzed 103 consecutive patients from a prospective stroke registry. They met the following criteria: CTA-proved large-vessel occlusion in the anterior circulation, ASPECTS above 6 on presenting cranial CT, revascularization by thrombectomy with the patient under general anesthesia within 6 hours after onset of symptoms, and available functional outcome (mRS) 90 days after onset.

RESULTS

The mean ventilation time was 128.07 ± 265.51 hours (median, 18.5 hours; range, 1-1244.7 hours). Prolonged ventilation was associated with pneumonia during hospitalization and unfavorable functional outcome (mRS ≥3) and death at follow-up (Mann-Whitney U test; P ≤ .001). According to receiver operating characteristic analysis, a cutoff after 24 hours predicted unfavorable functional outcome with a sensitivity and specificity of 60% and 78%, respectively. Our results imply that delayed extubation was not associated with a less favorable clinical outcome compared with immediate extubation after the procedure.

CONCLUSIONS

Short ventilation times are associated with a lower pneumonia rate and more favorable clinical outcome. Cautious interpretation of our data implies that whether patients are extubated immediately after the procedure is irrelevant for clinical outcome as long as ventilation does not exceed 24 hours.

[No improved survival rate in severely injured patients by prehospital intubation : A retrospective data analysis and matched-pair analysis]

BACKGROUND

Training programs for the treatment of trauma patients generally recommend establishing a secure airway if the patient presents with a Glasgow coma scale (GCS) score of less than 9; however, the evidence for its effectiveness is rather sparse. This study analyzed the effect of preclinical intubation on mortality of patients with a GCS <9 in an emergency medical situation.

METHODS

This retrospective analysis included patients who were primarily admitted to a German level 1 trauma center between 2002 and 2012 with an injury severity score (ISS) ≥ 16, a GCS < 9 and primary transport from the site of the accident. Data were collected from the trauma registry of the German Society for Trauma Surgery and from hospital records. A total of 455 patients were included and a matched-pair analysis of 62 patients was conducted.

RESULTS

Both analytical methods showed no significant reduction in mortality rate after prehospital intubation. In the retrospective analysis intubated patients presented with a significantly lower systolic blood pressure on admission, received a higher amount of fluid volume at all phases of treatment and arrived at the hospital after a prolonged rescue time. In the matched-pair analysis, intubated patients also received a higher amount of fluid volume and showed better peripheral oxygen saturation on admission. No further differences between the groups could be found.

CONCLUSION

It appears that preclinical intubation in trauma patients with a GCS < 9 does not result in a better outcome. The preclinical intubation resulted in a reduced systolic blood pressure on arrival at hospital, a prolonged preclinical rescue time and a greater amount of infused fluid volume.

Nutrition and health in amphibian husbandry

Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists' understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas.

Cost-efficient delay generator for fast terahertz imaging

We present a fast and low-cost delay generator for terahertz (THz) waves that transfers a rotational motion of a transparent dielectric cube into an effective THz delay. The device is easily implemented in the THz beam path and allows for coherent sampling over 40 ps with a scan rate of hundreds of hertz. Furthermore, we show that our approach is particularly suitable for fast THz imaging.

Terahertz plastic compound lenses

We present terahertz (THz) lenses made of highly refracting polymeric compounds which provide a better focusing performance and an increased functionality in comparison to conventional THz lenses. Using mixtures consisting of polypropylene (PP) and alumina as well as PP and zinc sulfide allows a significant increase of the refractive index while simultaneously keeping a low extinction and dispersion. With these new material combinations, lenses with an increased focusing capability are realized. This is evaluated by focal plane measurements using a fiber coupled THz time-domain spectrometer.

Sonographic discrimination of corticobasal degeneration vs progressive supranuclear palsy

OBJECTIVE

To study the use of brain parenchyma sonography (BPS) in discriminating between patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP).

METHODS

Thirteen patients with PSP and eight with CBD were studied with BPS according to a standardized protocol.

RESULTS

Seven (88%) of the eight CBD patients showed marked hyperechogenicity of the substantia nigra (SN) but none of eleven PSP patients (Mann-Whitney U test, p < 0.001). This finding indicated CBD with a positive predictive value of 100%. Marked dilatation of the third ventricle (width > 10 mm) was found in 10 (83%) of 12 PSP patients, but in none of the CBD patients (p < 0.005). BPS measurements of ventricle widths closely matched MRI measurements (Pearson correlation, r = 0.90, p < 0.001). The presence of at least one of the BPS findings 1) marked SN hyperechogenicity and 2) third-ventricle width < 10 mm indicated CBD with a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 80%. Other BPS findings such as echogenicity of lentiform and caudate nuclei and widths of the frontal horns did not discriminate between CBD and PSP. One PSP patient could not be assessed because of insufficient acoustic temporal bone windows.

CONCLUSIONS

Substantia nigra hyperechogenicity, reported earlier as characteristic brain parenchyma sonography finding in idiopathic Parkinson disease, is also typical for corticobasal degeneration.

Der Einsatz von Botulinumtoxin in der Therapie von Muskelschmerzen

The analgesic effects of botulinum toxin (BTX) have been discussed controversially due to substantial placebo effects and flaws in the study designs used. Additionally, pathophysiological concepts of pain and the specific analgesic mechanisms of BTX remain largely unclear. Apart from pain reduction through the well-documented effects of BTX at the neuromuscular endplate, additional analgesic mechanisms, including other synaptic and local effects, have been suggested. Currently, BTX can be recommended for pain treatment in dystonia and spasticity. In myofascial pain syndromes, pain relief by BTX injections has been reported, but definite proof according to evidence-based medicinal criteria is still lacking. In fibromyalgia, there seems to be no analgesic effect. The role of BTX in pain therapy is likely to increase in the future.

Brain parenchyma sonography discriminates Parkinson's disease and atypical parkinsonian syndromes

OBJECTIVE

To study the use of brain parenchyma sonography (BPS) in discriminating between patients with idiopathic PD (IPD) and atypical parkinsonian syndromes (APS).

METHODS

Twenty-five patients with APS, 9 with progressive supranuclear palsy (PSP) and 16 with multiple-system atrophy (MSA), and 25 age-matched patients with IPD were prospectively studied with BPS according to a standardized protocol.

RESULTS

Twenty-four of the 25 (96%) IPD patients exhibited hyperechogenicity of the substantia nigra (SN) but only 2 of 23 (9%) APS patients (Mann-Whitney U test, p < 0.001). In those two APS patients, SN hyperechogenicity was moderate only, whereas the remaining 21 APS patients had normal SN echogenicity. The specificity of SN hyperechogenicity in detection of clinically diagnosed IPD patients was 96%, and the sensitivity was 91%. If SN hyperechogenicity was marked, APS could be excluded because of a positive predictive value of 100% for IPD. Nucleus lentiformis hyperechogenicity was found in 17 of 22 (77%) APS patients but in only 5 of 22 (23%) IPD patients (Mann-Whitney U test, p < 0.001). Nucleus caudatus and thalamus echogenicity and widths of the third ventricle and of the frontal horns of the lateral ventricles did not discriminate between IPD and APS. Two patients with PSP could not be assessed because of an insufficient bone window.

CONCLUSIONS

BPS is a novel and noninvasive method to differentiate highly specifically between IPD and APS. Therefore, BPS might become a standard investigation in parkinsonian disorders.

A new class of drugs for BNCT? Borylated derivatives of ferrocenium compounds in animal experiments

A new class of drugs, borylated derivatives of ferrocenium compounds, which show a comparatively facile synthesis is investigated on their boron neutron capture accumulation. Investigations focused on the fast and effective testing of 12 ferrocene derivatives with tetracoordinated boron atoms, which should accumulate in rodent tumors. The macroscopic studies on time-dependent boron distributions and boron concentrations in mice were carried out by inductively coupled plasma-atomic emission spectrometry, inductively coupled plasma-mass spectrometry, and quantitative neutron capture radiography. The determination of boron concentrations after injection of 2b showed high boron contents in spleen, liver, kidneys, less in lung and muscle, and poor in integral blood, blood plasma, tumor, and brain. It is interesting to note that 2b penetrates the blood-brain barrier which may be advantageous in the treatment of astrocytomas and glioblastomas.

Velocity not acceleration of self-motion mediates vestibular-visual interaction

We investigated the influence of vestibular stimulation with different angular accelerations and velocities on the perception of visual motion direction. Constant accelerations resulting in different angular velocities and constant angular velocities obtained at different accelerations were combined in twenty healthy subjects. Random-dot kinematograms with coherently moving pixels and randomly moving pixels were used as visual stimuli during whole-body rotations. The smallest percentage of coherently moving pixels leading to a clear perception of motion direction was taken as the perception threshold. Perception thresholds significantly increased with increasing angular velocity. Increased acceleration, however, had no significant effect on the perception thresholds. We conclude that the achieved angular velocity, and not acceleration, is the predominant factor in the processing of vestibular-visual interaction.

Fructose- and sorbitol-reduced diet improves mood and gastrointestinal disturbances in fructose malabsorbers

BACKGROUND

Fructose malabsorption is characterized by the inability to absorb fructose efficiently. As a consequence fructose reaches the colon where it is broken down by bacteria to short fatty acids, CO2 and H2. Bloating, cramps, osmotic diarrhea and other symptoms of irritable bowel syndrome are the consequences and can be seen in about 50% of fructose malabsorbers. We have previously shown that fructose malabsorption is associated with early signs of mental depression and low serum tryptophan concentrations. It was therefore of interest whether a fructose-reduced diet could not only improve gastrointestinal complaints but also depressive signs seen in fructose malabsorbers.

METHODS

Fifty-three adults (12 males, 41 females), who were identified as fructose malabsorbers according to their breath-H2 concentrations, filled out a Beck's depression inventory-questionnaire, and a questionnaire with arbitrary scales for measurement of meteorism, stool frequency and quality of life for a 4-week period before dietary intervention and 4 weeks after dietary change as for fructose- and sorbitol-reduced diet.

RESULTS

Depression scores were reduced by 65.2% after 4 weeks of diet (P < 0.0001), and there was a significant reduction of meteorism (P < 0.0001) and stool frequency (P < 0.01). Improvement of signs of depression and of meteorism was more pronounced in females than in males.

CONCLUSION

Fructose- and sorbitol-reduced diet in subjects with fructose malabsorption does not only reduce gastrointestinal symptoms but also improves mood and early signs of depression.

Pavlovian conditioning of taste aversion using a motion sickness paradigm

OBJECTIVE

Pavlovian conditioning of taste aversion has rarely been investigated in healthy humans using motion sickness as the unconditioned stimulus (US).

METHODS

Ninety subjects were pretested for susceptibility to illusory motion (vection) in a rotating drum. Thirty-two subjects susceptible to pseudomotion were assigned randomly to two groups and received either water 1 hour before rotation and a novel taste (elderberry juice, conditioned stimulus, [CS]) immediately before rotation in a rotating chair (conditioning group), or the sequence of water and juice was reversed (control group). During the test session 1 week later, all subjects were exposed to water 1 hour before and juice immediately before rotation. The amount of liquids ingested, nausea ratings, rotation tolerance, and blood levels of hormones (ACTH, ADH, PP) were evaluated.

RESULTS

Subjects in the conditioning group developed taste aversion toward the novel taste, but not subjects in the control group. Postrotation nausea rating was affected marginally by conditioning, but rotation tolerance was not changed by conditioning. ACTH and ADH but not PP levels increased with rotation, but were unaffected by conditioning.

CONCLUSIONS

Pavlovian conditioning of behavioral, but not of endocrine, indicators was effective in susceptible subjects using a rotating chair as US and a single CS-US pairing.

Determination of metal additives and bromine in recycled thermoplasts from electronic waste by TXRF analysis

A new method for analysis of metal additives in recycled thermoplasts from electronic waste was developed, based on dissolving the samples in an organic solvent and subsequent analysis of the corresponding solutions or suspensions by total-reflection X-ray fluorescence spectroscopy (TXRF). The procedure proved to be considerably less time consuming than the conventional digestion of the polymer matrix. Additives containing Ti, Zn, Br, Cd, Sn, Sb, and Pb were analyzed in a hundred randomly selected samples from recycling, which provided an overview of the range of elemental concentrations in thermoplasts utilized for consumer electronics. The results were validated independently by instrumental neutron activation analysis (INAA), subsequent regression analysis confirmed the trueness of the chosen approach.

Torsional eye movements are facilitated during perception of self-motion

Visual motion in the roll plane elicits torsional optokinetic nystagmus (tOKN) with intermittent periods of illusory, contradirectional self-motion (circularvection, CV). The CV may also have a component of whole-body tilt if the axis of stimulus rotation is not aligned with the direction of gravity. We report how the characteristics of tOKN are affected by the presence of CV. Subjects had their eye movements recorded by VOG whilst viewing a full-field stimulus rotating at 30-60 degrees/s about their naso-occipital axis. They were tested in upright and supine posture and signalled the presence-absence of CV with a pushbutton. In both postures, during CV, tOKN slow-phase gain was found to be enhanced and average torsional eye position shifted in the direction opposite to stimulus rotation. When supine, slow-phase gain was greater than when upright both during the perception of object-motion and during CV. The effects may be explained in terms of a relegation of restraining vestibular input to the torsional oculomotor system during CV and illusory tilt.

New drugs for BNCT: an experimental approach

New kinds of boron-containing drugs were developed and tested in several murine tumor models. The boron-containing ether lipid B-Et-11-OMe was injected in mammary carcinoma (AT17) and osteosarcoma (OTS-64) bearing mice. Furthermore boron-substituted ferrocenium derivatives were tested. Two were excessively toxic; the third could be investigated. Boron accumulation and time-dependent biodistribution were determined using alpha-particle sensitive films and inductively coupled plasma-atomic emission pectrometry (ICP-AES) and -mass spectrometry (ICP-MS) of tumors, organs and tissues. Additionally, a new method of boron detection by NMR is in preparation.

Visual motion direction evoked potentials are direction specifically influenced by concurrent vestibular stimulation

We investigated the influence of vestibular stimulation on visual motion-direction perception using electrophysiological recordings. Visual motion-direction evoked potentials decreased in area during the rotation of subjects about their vertical z-axis, when visual and vestibular motion directions were incongruous (visual and vestibular stimulation in the same directions). Visual pattern onset evoked potentials, however, remained unaffected by vestibular stimulation. For rotations about the interaural y-axis, decreased area of visual-direction evoked potentials was found for both congruous and incongruous combinations of visual and vestibular stimulation. The results are in accordance with previous psychophysically obtained data and discussed in terms of postnatal development and neurophysiological optimization processes. An interaction model focused on reciprocal inhibition of the middle temporal visual (MT) area and the medial superior temporal (MST) area is presented.

Electrophysiological evidence for direction-specific rotary evoked potentials in human subjects--a topographical study

The spatio-temporal characteristics of rotary evoked potentials are unknown up to now. Transient motions with sinusoidal velocity profile (60 degrees , 47.12 degrees /s, 74.02 degrees /s2, duration 2 s) were alternately applied (rightward/leftward) to 12 healthy subjects. Fixation of a target-cross moving with them suppressed the vestibulo-ocular reflex. Quasi-DC-scalp potentials were recorded from a total of 21 equidistant (3 cm) locations (single sweep: 5 s, 0.016-100 Hz). Brain activity evoked by rotary stimulation is dominated by a late, long-lasting component within a mean peak latency of about 1800 ms after motion onset. Topographic distribution over both hemispheres specifically depends upon the direction of rotation and is mirror-symmetric with respect to the sagittal midline. The gradient of the potential field obtained shows its maximum along a lateral orientation corresponding to the temporo-parietal orientation of vestibular cortical projection areas.

Perception of direction of visual motion. I. Influence of angular body acceleration and tilt

We investigated, psychophysically, the influence of body rotation on visual motion direction thresholds for both upright sitting and tilted observers. Four angular accelerations (0, 20, 40 and 60 degrees/s2) were combined with 3 concurrent backward-tilt positions (0, 45 and 90 degrees). This led to combined stimulation of the semicircular canals and otoliths. Vestibular stimulation was combined with a visual motion stimulus. Random-dot kinematograms in which varying percentages of pixels coherently moving to the left were presented upon a background of otherwise randomly moving pixels (random walk). The smallest percentage of coherently moving pixels leading to a clear perception of motion direction represented as the perceptual threshold. Angular accelerations about the longitudinal body axis significantly increased motion-direction thresholds. Concurrent backward tilt did not influence thresholds. These results differ from those of studies in which translational linear acceleration was employed. Our results support the view that it is necessary to distinguish between linear acceleration caused by gravitational forces and that caused by additional linear accelerations about the x-, y-, and z-axes.

Perception of direction of visual motion. II. Influence of linear body acceleration

We investigated whether linear whole-body acceleration along the interaural y-axis influenced the concurrent perception of visual motion direction as has been shown for angular accelerations. A sled running on air bearings along a 7.5-m track was used to accelerate 18 subjects at two different linear accelerations. These young, healthy volunteers, aged 25.50 +/- 7.38 years, used a joystick to indicate whether or not they perceived visual motion to the left within a random-dot kinematogram continuously presented on a monitor moving with them. The percentage of coherently leftward moving pixels presented for a 640-ms period during acceleration was adjusted according to a Modified Binary Search (MOBS) procedure. Six conditions were tested, two acceleration levels of 1 and 2 m/s2 to both left and right with, at the higher acceleration, two different times of visual motion presentation. Conditions were sequenced by means of a 6 x 6 Latin square balanced for order and carry over. A MANOVA did not show any statistically significant effects either for the independent variables acceleration, velocity, and direction of motion of the sled or for their interactions. The results obtained are in clear contrast to those obtained under rotatory stimulation. We conclude that the otolithic contribution to vestibular-visual motion processing is negligible.

Position and velocity responses from the otoliths and the canals: results from ESA's parabolic flights

BACKGROUND

Transient (i.e., phasic) bell-shaped vestibularly evoked potentials (VESTEP's) were recorded from the human scalp during whole body rotation about the vertical z-axis using a multi-axis rotary chair (yaw-motion). For pitch-motions about the interaural y-axis, however, a sustained (i.e., tonic) VESTEP was recorded, presumably because of the additional otolithic stimulation.

HYPOTHESIS

During microgravity, only phasic VESTEP's were recorded because pitch-motions stimulate only the vertical semicircular canals without otolithic contamination.

METHODS

The motion profile applied simulated the form of a natural smooth head movement ("raised cosine"). It was designed to minimize all possible sources of mechanical, electrical, and physiological artifacts. With this motion profile, seated subjects were tilted 90 degrees nose-down or 90 degrees nose-up about their interaural y-axis ("pitch") thus stimulating the vertical semicircular canals and the otoliths. In addition, the raised cosine velocity profile was applied during the microgravity phases of a total of 90 parabolic flight maneuvers, thus stimulating the vertical canals without additional otolithic stimulation.

RESULTS

A transient (phasic) bell-shaped VESTEP was found in the Earth-bound laboratory for backward-tilts corresponding to the velocity profile used. For nose-down tilts, however, a sustained (tonic) negativity was found which matched the applied position profile. In microgravity, only the transient bell-shaped responses could be recorded irrespective of tilt direction.

CONCLUSION

These results are interpreted in terms of both a position response generated by pitch-down and a velocity response caused by pitch-up motions. This differentiation might prove to be a useful electrophysiological tool in oto-neurological diagnosis to distinguish between otolithic and canal disorders.

Uptake and distribution of the boron-containing ether lipid B-Et-11-OMe in tumor-bearing mice

Ether lipids in general are accumulated in tumor tissue with a favorable tumor/healthy tissue ratio. The uptake of the boron-containing analog rac-1-(9-o-carboranyl)nonyl-2-methyl-glycero-3-phosphocholine (B-Et-11-OMe) was studied in C3H mice bearing the murine mammary carcinoma AT17 and in BALB/c mice bearing an osteosarcoma. Boron concentrations of tumor, blood, liver and kidney were followed up to 48 h by inductively coupled plasma emission spectrometry and inductively coupled plasma mass spectrometry. Boron concentration in AT17 mamma carcinoma rose up to 2 mg/kg and the tumor/blood ratio rose to 0.5. The bulk was taken up by the liver. Osteosarcoma did not take up B-Et-11-OMe. This result constitutes a significant contrast to the behavior of published (non-boron-containing) analogs. It is interpreted in terms of critical micellar concentration (CMC). Whereas earlier work with ether lipids was done well below CMC, this study was undertaken above. Further studies will concentrate on syntheses of high CMC analogs.

Processing of visual motion direction in the fronto-parallel plane in the stationary or moving observer

To examine the effect of concurrent self-motion on the perception of the direction of object-motion, random-dot kinematograms were employed in which the strength of the directional signal was manipulated by varying the percentage of coherently moving pixels. The subject's task was to indicate the motion direction of briefly presented displays while undergoing whole body rotations with angular accelerations of 0, 5, 15, or 45 degrees/s2. The perception of the direction of visual motion in the horizontal plane was impaired only when visual and vestibular motion directions were incongruous. The impairment increases with both increasing angular acceleration and decreasing percentage of coherently moving pixels. For object-motion in the vertical plane, an impairment was found for both congruous and incongruous combination of visual and vestibular stimulation, although not as pronounced for the latter (i.e., visual upward, vestibular downward stimulation, and vice versa). These results are discussed in terms of postnatal development and neurophysiological optimization processes resulting from intersensory 'updating' through every-day experience of object-motion during self-motion.

Vestibularly evoked potentials (VESTEPs) of the horizontal semicircular canals under different body positions in space

We recorded vestibularly evoked potentials (VESTEPs) using natural vestibular stimuli simulating the form of a normal head movement ("raised cosine"). Its smooth course was designed to minimize all possible sources of artifacts of mechanical, electrical, and physiological origin. This motion profile was applied to subjects (Ss) sitting upright, thus stimulating the horizontal semicircular canals alone, as well as when they were tilted in different positions in steps of 30 degrees about the interaural y-axis, which had the effect of modulating the otolithic contribution to the horizontal VESTEP. The transient bell-shaped VESTEP recorded in the upright sitting S was more and more superimposed or replaced by a sustained negativity the more the S was tilted toward a horizontal position. Thus, the VESTEP gradually changes from a velocity response in the upright S (canals only) to a position response in the lying S (canals plus otoliths). Differences in the VESTEPs obtained for clockwise (cw) and counterclockwise (ccw) turns in the tilted S were found. The reason for this is not clear at present and requires further experimentation. However, the VESTEPs obtained under conditions involving backward tilts and cw turns corresponded to those obtained with forward tilts and ccw turns. A similar relationship was found for the VESTEPs obtained with backward tilts and ccw turns and those obtained with forward tilts and cw turns. The physiological basis of this is discussed.

MARDER--multi-axes rotation device for experimental research. A new concept for investigations of the vestibular, oculomotor, and visual systems of humans in three-dimensional space

A hydraulically driven, digitally servo-controlled multi-axes rotary chair is described. This device generates motion profiles with the subjects head in the center of rotation mainly in order to adequately stimulate the semicircular canals which are sensitive sensors for angular accelerations. This newly developed apparatus allows for motion stimuli which are below the vestibular threshold up to accelerations of 12 rad/s2 (688 degrees/s2) and is thus suitable for a variety of experiments in the field of vestibular, oculomotor, and intersensory research in 3-dimensional space.

Identification of the visual motion area (area V5) in the human brain by dipole source analysis

The retinal periphery of nine healthy subjects was stimulated with computer-generated random-dot kinematograms. These stimuli provided almost isolated visual motion information and minimal position cues. Pattern-reversal stimuli at the same location in the visual field were used for control. Stimulus-related electrical brain activity was recorded from 29 scalp electrodes. Total mean and individual data were analyzed with a spatiotemporal multiple dipole model. The scalp potentials showed a different spatial distribution for motion and pattern stimulation in the time range of 160-200 ms. In this epoch, the predominant motion-related source activity was localized in the region of the contralateral occipital-temporal-parietal border. A significant ipsilateral source activity was not found. The predominant source activity related to the pattern stimulus occurred in the same epoch. The corresponding equivalent dipole was localized more medially and deeper in the brain. The orientation of these major dipole activities was markedly different. These dipoles appeared to represent activity of distinct extrastriate areas, in contrast to earlier activity which was modelled by more posterior dipoles in the occipital lobe. The latter dipoles were at comparable contralateral locations and had similar peak activities around 100 ms, suggesting an origin in the striate cortex.

Impairment of auditory processing by simultaneous vestibular stimulation: psychophysical and electrophysiological data

The aim of the experiments reported here was to demonstrate auditory-vestibular interaction both on a psychophysical and on an electrophysiological basis in humans. These results correspond to those recently obtained during simultaneous visual and vestibular stimulation and illustrate experimentally the importance of auditory information processing in spatial orientation. Time to detect the motion of a sound source is significantly increased when simultaneous vestibular stimulation is induced by passive sinusoidal head oscillations. This effect increased with the peak acceleration of the vestibular stimulus (197, 790 and 1777 degrees/s2). Vestibular influence on general auditory information processing without the quality of (object-) motion could be electrophysiologically demonstrated by means of brainstem auditory evoked potentials. The amplitude of component V generated by the inferior colliculi or by neuronal structures located slightly lower in the auditory tract was significantly reduced during concurrent vestibular stimulation. This neuronal brainstem area is a predominant location of biconvergent vestibulo-auditory neurons mediating intersensory information processing at an early neuronal level.

Electrophysiological evidence for visual-vestibular interaction in man

The aim of the experiments reported here was to confirm electrophysiologically the results of psychophysical experiments, which demonstrated that thresholds for object-motion detection are significantly raised during both concurrent active or passive sinusoidal head oscillations and during visually induced self-motion perception (circularvection, CV). This intersensory inhibition could now be demonstrated electrophysiologically by recording visual motion evoked potentials both during concurrent sinusoidal head oscillations and during visually induced apparent self-motion of the objectively stationary subject. Recordings of visual contrast reversal evoked potentials failed to reveal such an interaction. Perceptual phenomena with multisensory stimulation are well described in the literature. Berthoz et al. demonstrated the dominant influence of the visual channel on vestibular thresholds such that the detection of a suprathreshold vestibular stimulation was clearly impaired by a simultaneously moving visual pattern inducing linearvection and vice versa. Comparable results are reported for circularvection. Evidence for inhibitory interaction between object-motion and simultaneous self-motion perception also exists. Electrophysiological data on intersensory interaction in humans have only been reported between electrical stimulation of a limb and its concurrent movement by means of scalp-recorded somatosensory-evoked potentials (SSEPs) (e.g. refs. 3, 5). Electrophysiological evidence for the interaction of visual object-motion and vestibular self-motion perception in humans has never been reported in the literature thus far, though Hood and Kayan demonstrated that retinal image motion makes a contribution to the vestibularly evoked bioelectric response.

Active immunization against gonadotropin-releasing hormone combined with androgen supplementation is a promising antifertility vaccine for males

Male rats and rabbits were immunized against gonadotropin-releasing hormone (GnRH) conjugated to tetanus toxoid (GnRH10-TT) using only materials approved for humans. Testosterone (T)-releasing implants or the long-lasting T ester testosterone-17-trans-4-n-butyl-cyclohexane carboxylate (TE) was used as supplemental androgen for maintaining libido. Immunization against GnRH10-TT effectively suppressed fertility (spermatogenesis) in rats and rabbits. Neither T nor TE administration restored fertility. Both androgens were effective in maintaining normal libido in rats. TE, which is not hydrolyzed in rabbits, was less effective in maintaining normal ejaculatory behavior in this species. Active immunization against GnRH could be a convenient and cost-effective method of fertility control in males.

Influence of head or trunk oscillations on visually induced self-motion perception in humans

The influence of concurrent head or trunk movements on optokinetically induced self-motion perception has been investigated by measuring circularvection (CV) latencies. Active head as well as passive trunk oscillation cause an increase in circularvection latency of about 50% as compared to latencies with the head and trunk stationary during full field optokinetic stimulation. The results point towards an intersensory inhibition of self-motion perception.

Object-motion detection affected by concurrent self-motion perception: psychophysics of a new phenomenon

Thresholds for object-motion detection are significantly raised when concurrent self-motion perception is induced by either vestibular, or visual, or cervico-somatosensory stimulation. Active sinusoidal horizontal head oscillations with compensatory vestibulo-ocular reflex (VOR) and foveal or eccentrical target presentation; 'passive' head movements with fixation suppression of the VOR; pure body oscillations with the head fixed in space (cervical stimulation); optokinetically induced apparent self-motion (circularvection). This new visual phenomenon of a physiological 'inhibitory interaction' between object- and self-motion perception seems to have a somatosensory motor analogue. It may reflect the disadventageous side effect due to unspecificness of an otherwise beneficial space constancy mechanism, which provides us with the image of a stable world during locomotion.

European vestibular experiments on the Spacelab-1 mission: 5. Contribution of the otoliths to the vertical vestibulo-ocular reflex

The gain of the vestibulo-ocular reflex in the sagittal plane may be due to a cooperation between otoliths and the vertical semi-circular canals. The present space experiment was aimed at studying the influence of the absence of gravity stimulation on the otoliths, by comparing VOR gain and phase in space and on ground. Measurements were taken the 5th and the 7th day of flight, the subject being asked to perform, eyes closed, active head oscillations in pitch while fixating an imaginary target in front of him. No significant decrease of the VOR gain was found in space, but a change in phase was noted. A significant increase of the VOR gain was found 14 h after landing. Control experiments have been done on ground on several subjects. They indicate that pitch VOR gain during active head movements is about one, with eyes open in darkness at 1 Hz.

European vestibular experiments on the Spacelab-1 mission: 2. Experimental equipment and methods

A series of vestibular experiments were performed in conjunction with the first Spacelab mission, consisting of sets of pre-, in- and postflight tests. A multipurpose experimental apparatus used for the diverse flight and ground tests is presented. Additional apparatus together with the multi-purpose package were used in the baseline data collection facility at the landing site at NASA Dryden Flight Research Facility for the ground tests. The tests involved optokinetic, caloric and mechanical (whole-body or head-alone) stimulation. The latter included linear acceleration in the subject's x, y and z axes, static roll and yaw about an earth-vertical axis. Physiological parameters such as electro-oculogram (EOG), blood-volume-pulse (BVP), respiration, as well as the stimulus variables such as acceleration and caloric temperature were transmitted to the ground and recorded there. The flight and ground testing schedules are outlined. Problems arising from this complex venture are discussed, and some suggestions are made for future improvement.

Differential effects of ambivalent visual-vestibular-somatosensory stimulation on the perception of self-motion

The direction of perceived self-motion was determined as a function of combined visual-vestibular and vestibulo-somatosensory stimulations about the earth's vertical z-axis by means of a rotary chair and drum system. The predominant influence of concurrent antagonistic vestibular stimulation on circular vection (CV) even at small accelerations has been demonstrated by several studies in the past. The results of the present paper do not confirm the generally assumed influence of the vestibular system on exocentric motion perception, but instead produce evidence of the dominance of the visual channel even at high acceleration levels. Using a joystick to indicate perceived self-motion, we found the following: Constant CV (visual stimulus velocity: 40 degrees/s) could only be cancelled by vestibular stimulations at oppositely directed mean angular accelerations of 26.9 +/- 9.1 degrees/s2. Smaller accelerations led merely to an acceleration level-related decrease in the perceived velocity of CV. Despite a clear decision with respect to the direction of the perceived motion, subjects (Ss) reported dizziness or even strong motion sickness symptoms. Similar results were obtained with vestibulo-somatosensory interactions. The results are interpreted in terms of an intensive visual support in the processing of visual-vestibular signals, particularly at cortical level, assuming a cortical velocity generator (CVG).

Interaction between perceived self-motion and object-motion impairs vehicle guidance

When one is riding in a vehicle, perceptual thresholds for motion of objects are significantly elevated above those determined under corresponding but simulated conditions in the laboratory without concurrent self-motion perception. Authorities on road traffic accidents should thus consider an additional perceptual time of at least 300 milliseconds for detecting critical changes in headway beyond the usual reaction time. Detection times thus corrected consequently lead to an alteration of our conception of safe intervehicle distances in a convoy. This elevation of thresholds for object-motion during self-motion, with its consequences for visual control of vehicle guidance, can be seen as a disadvantageous side effect of an otherwise beneficial space-constancy mechanism, which provides us with a stable world during locomotion.

Effects of rectilinear acceleration and optokinetic and caloric stimulations in space

During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight. The most significant result was that caloric mystagmus of the same direction as on the earth could also be evoked in the weightless environment.

[Visual prevention from motion sickness in cars]

The differential effects of vision on motion sickness in cars were tested under real road conditions using linear accelerations, in order to confirm earlier laboratory results on visual modulation of vestibular nausea induced by angular accelerations of the body. The 18 voluntary subjects were exposed to repetitive braking maneuvers (linear accelerations: 0.1-1.2 g) on a highway. The simultaneous visual stimulus conditions for the 3 separate days were: I) eyes open, visual control of car motion; II) eyes closed; III) eyes open, artificial stationary visual field (reading). The severity of motion sickness (magnitude estimation 1-10) was a function of the visual stimulus condition with significant differences among these conditions: I) moderate nausea (less than 1) with adequate visual motion perception; II) medium nausea (approximately equal to 2) with eyes closed and somatosensory-vestibular excitation only; III) strong nausea (greater than 5) with conflicting sensory input, when vestibular acceleration is in disagreement with the visual information of no movement. Providing ample peripheral vision of the relatively moving surround is the best strategy to alleviate car sickness.