Recurrent outbreaks caused by the same Salmonella enterica serovar Infantis clone in a German rehabilitation oncology clinic from 2002 to 2009.

BACKGROUND: Repeated outbreaks of salmonellosis caused by Salmonella enterica serovar Infantis at a rehabilitation clinic in Germany were investigated microbiologically from August 2002 to August 2009. AIM: To identify the sources of transmission and characterize the S. enterica serovar Infantis isolates. METHODS: Associated with these outbreaks, isolates from 98 patients, two kitchen staff, five food samples, four swabs of kitchen facilities, three samples of chicken faeces and one sample of sewage water were evaluated by phage typing. All S. enterica serovar Infantis isolates investigated (N=113) were related to phage type (PT) 29. Additionally, 44 of the 113 isolates were selected at random for typing by XbaI macrorestriction and pulsed-field gel electrophoresis (PFGE). FINDINGS: Typing of the 44 isolates showed that the recurrent infections were caused by the single clone PT 29/XB27+44 (42/44, 95.5%). The most likely route of transmission was only identified in the last outbreak in 2009 within the present study. It was found to be cross-contamination in the kitchen facilities (emanating from a contaminated wooden panel), in combination with carriers among the kitchen staff. CONCLUSIONS: This study demonstrated important details of hospital-specific epidemiological processes, and alludes to a long-term reservoir of an epidemic clone of S. enterica serovar Infantis either in a backyard flock of poultry or in an inanimate kitchen reservoir.

[Sensitization to airborne ragweed pollen--a cause of allergic respiratory diseases in Germany?]. / Sensibilisierung gegen Ambrosiapollen--Eine Ursache für allergische Atemwegserkrankungen in Deutschland?

BACKGROUND AND OBJECTIVE: Allergic skin and respiratory diseases show a high prevalence in most industrial countries. In addition, during the last years ragweed colonization has increased in Europe. Ambrosia pollen ( AMBROSIA ARTEMISIIFOLIA L. - common ragweed) are highly allergenic. Due to the late flowering time (august/September) of ragweed this can result in increasing health threats for allergic populations. This is of particular importance for those who already are sensitive to some grass or tree pollen. These individuals can then suffer from allergies during nearly the whole year. The present study examined the prevalence of sensitization to ragweed in German children and possible health implications. METHODS: Between 2004 and 2007 sera of 1323 10-years old children in Baden Württemberg were tested in-vitro for specific IgE-antibodies against common aeroallergens including ragweed pollen. RESULTS: Specific IgE-antibodies to extracts of common ragweed pollen were present in 10 - 17 % of the tested sera depending on the year of investigation. CONCLUSION: The determined specific IgE-antibodies may be the result of a direct sensitization to ragweed pollen or correspond to cross-reactivity to other plants of the asteraceae subfamily or some nutritional allergens. The detection of sensitization to ragweed pollen does not prove actual allergic disease. However, a ragweed derived allergy should be considered in the differential diagnosis when allergic symptoms are present in direct connection to the flowering-time of ragweed. Ragweed plants should be removed and the spread of the plant 'restricted', as experiences in other countries with already wide spreading show.

Ground based eccentric chair experiments.

Two subjects were rotated eccentrically in a manner described before. In contrast to a normal control group settings of a luminous line to the subjective vertical were almost unrelated to the gravitoinertial summation vector of gravity and centrifugal forces about four weeks before and totally so shortly after space flight. Only after four days post flight had passed a noticeable relation to the gravitoinertial vector re-established itself in the one subject which actually flew. The correspondence became normal six days after flight. Since there were no clinical abnormalities evident in the subjects, it is suggested, that both subjects suppressed their vestibular information presumably as an effect of vestibular deconditioning training before flight. In addition as a consequence of the flight experience one subject continued to ignore it several days after the flight.

Ocular torsion during microgravity on a space mission in 1992.

On a space mission in 1992 we investigated the effect of pure neck receptor stimulation on eye roll position in space. To do this, we used the flash afterimage method. We found that eye rotations in static tilted head positions are absent in weightlessness. This suggests that in microgravity the neck position receptors do not contribute to a measurable extent to static OCR.

Influence of gravity on the eye movement response elicited by periodic lateral linear acceleration.

Periodic linear acceleration elicits eye movements in human beings. This is generally considered to be the result of the otolithic-ocular reflex (OOR). However, otolith organs respond not only to the resultant inertial force caused by head motion, but also to the gravitational force. We investigated the influence of the resultant gravito-inertial vector on the OOR using a linear acceleration sled. Subjects were 10 healthy volunteers. The sled moving back and forth parallel to the lateral head axis stimulated the subjects. We tested each subject in 7 different positions in the pitch plane. Horizontal eye movements with nystagmic patterns were elicited by these stimuli. The results indicate that the responses were larger in the forward tilted positions than in the backward tilted positions. It can be concluded that the horizontal OOR is influenced by the gravity vector. The cause of this phenomenon is still unclear. However, it could be closely related to the nystagmus observed during off vertical axis rotation.

Oculovestibular interactions under microgravity.

On a space mission in March 1992 a set of experiments were performed aimed at clarifying the interaction between visual, proprioceptive and vestibular inputs to the equilibrium system. Using the VESTA goggle facility from the European Space Agency we investigated the effect of pure neck receptor stimulation on eye position as measured by the flash afterimage method and on perception of a head-fixed luminous line in space. Space vestibular adaptation processes were measured by rotating pattern perception during prescribed head movements. It was found that static ocular counterrotation does not occur under microgravity conditions. This result suggests that the neck receptors apparently do not contribute to a measurable extent. The subjective orientation of a vertical line was perceived correctly inflight. Obviously neck receptors on the perception level can fully substitute for the ineffective equilibrium organs of the inner ear within less than 4 days. The rotating pattern perception during different head motion patterns is not influenced by the absence of a gravity reference.

Responses to eccentric rotation in two space-bound subjects.

Two subjects were rotated eccentrically in the manner described previously. In contrast to a normal control group, settings of a luminous line to the subjective vertical were almost unrelated to the gravitoinertial vector before, and totally so shortly after, space flight. Only 3 days postflight did a clear relation to the gravitoinertial vector re-establish itself in the one subject who actually flew. The correspondence became normal 5 days after the flight. Since there were no clinical abnormalities evident in the subjects, it is suggested that both subjects suppressed their vestibular information, presumably as an effect of vestibular deconditioning training before the flight. In addition, as a consequence of the flight experience one subject continued to ignore it several days after the flight.

Will man need the vestibular system in generations to come? A slightly heretical review.

Some people are of the opinion, that man's evolution reached a plateau when he became self-aware. Thus, the argument goes, he was enabled to reflect on what happened to him and what he did to his environment. Subsequent to that man would think ahead to the consequences of his actions and thereby actively shape his future to ensure optimal survival of his species. And this state of course no longer could be called evolution in the classical sense. Need one comment on the vanity of the hope for such a state? Let us assume then, that the evolution of man has not ended, but will continue and that man has barely a clue, yet, as to the direction it may lead.

Clinical verification of a unilateral otolith test.

In a previous study we reported promising results for a new test to differentiate in vivo unilateral otolith functions. That study pointed to a need for further validation on known pathological cases. In this presentation we will detail the results gathered on a group of clinically verified vestibular defectives (verum) and a normal (control) group. The subjects in the verum group were former patients of the ENT clinic of the university hospital. These subjects had usually suffered from neurinoma of the VIIth cranial nerve or inner ear infections. All had reguired surgical intervention including removal of the vestibular system. The patients were contacted usually two or more years postoperatively. A group of students from the pre- and clinical phase of medical training served as control. Both groups were subjected to standardized clinical tests. These tests served to reconfirm the intra- or postoperative diagnosis of unilateral vestibular loss in the verum group. In the control group they had to establish the normalcy of the responses of the vestibular system. Both groups then underwent testing on our eccentric rotary chain in the manner described before. Preliminary results of the trials indicate that this test may indeed for the first time offer a chance to look at isolated otolith apparati in vivo.

Parabolic flight as a tool to measure ocular counterrotation in a reduced force environment.

Five unmedicated subjects were flown in parabolic flight. The aircraft, a Caravelle, performed single parabolae every 2 to four minutes. This resulted in alternating phases of normal, hyper-, hypo- and again hyper-gravity. Subjects sat yoga fashion upright facing towards the aircraft cockpit. Head and/or trunk were deflected 30 degrees from the upright, stimulating otolith and/or neck receptors. During each pullup, low-g phase and pullout of the parabolae a picture of the left eye was recorded on video tape. On the ground ocular roll (OCR) was determined from these video recordings. OCR ranged from 0.9 to 6.9 degrees in l-g and from 1 to 7.2 degrees under high-g, depending on head and trunk position. Neck receptor contribution was found to induce OCR of 0.2 degree to 2.1 degrees in two subjects.

Subjective luminous line perception under changing g-load and body-positions in parabolic flight.

Five healthy subjects were subjected to parabolic flight with laterally tilted head, trunk, or body position. A vertical luminous line was viewed by the subjects in a head-fixed goggle device. During normal, hyper- and hypogravity phases subjective luminous line orientation was measured. The data imply that stimulation of the neck position receptors markedly influences the perception of the subjective vertical as well as mechanisms of convergence of otolithic signals and visual information within the brain.

Influence of gravity vector on eye movement elicited by linear acceleration.

When the body/head motion is sensed by otolith organs, they respond not only to the resultant acceleration of the motion but also to the gravitational force. We investigated the influence of the gravity vector on the otolithic-ocular reflex caused by motion in normal subjects. The sled type linear accelerator, moving back and forth with a frequency of 0.25 Hz and an amplitude of 2 m, generated right-left linear acceleration with a maximum magnitude of 0.5 g. We tested every subject under seven different postures: 1) 135 degrees forward tilted (F.T.), 2) 90 degrees F.T., 3) 45 degrees F.T., 4) upright sitting, 5) 45 degrees backward tilted (B.T.), 6) 90 degrees B.T., and 7) 135 degrees B.T. Horizontal eye movements with nystagmic pattern were elicited by these stimulations and were recorded by EOG. The eye movement data were analyzed by using a computer with the following procedure. After extraction of saccadic components from the data, the remaining parts were connected smoothly. The waves reconstructed in this manner, considered to be primary otolithic-ocular responses, were processed with the FFT method for calculating the amplitude of the component at 0.25 Hz. As a result, the responses were larger in the forward tilted postures than in the backward tilted postures.

Transition from self tilt to object tilt during maintained lateral tilt in parabolic flight.

19 young healthy subjects were subjected to parabolic rollercoaster flight. A horizontal luminous line was seen by the subjects in a headfixed goggle device. During the hypergravic phases of parabolic flight the luminous line seemed to rotate into and during the hypogravic phase against the direction of static head tilt. Ocular counter rotation and activity of the neck position receptors cannot explain these subjective rotations. We conclude that information from the otolith system, converging with visual information within the brain, dislocated the headfixed visual target line. While the retinal image of the luminous line remains unchanged, loading and unloading the otoliths in parabolic flight changes the sensation of self tilt into object tilt, hereby subjectively rotating visual targets such as the luminous line.

Unilateral centrifugation of the otoliths as a new method to determine bilateral asymmetries of the otolith apparatus in man.

Ten healthy subjects were eccentrically rotated with constant speed on a Barany chair. Setting of a luminous line (LL) to the subjective vertical and ocular counter-roll (OCR) were evaluated. During eccentric position rotation subjects consistently reported illusory rotation and set the LL to an angle correlating to centrifugal force. At the same time an OCR of opposite direction was measured. In one patient, labyrinthectomized on the right side, only counterclockwise rotation of the luminous line was observed. Differences between "inner" and "outer" eye were evident for luminous line settings and OCR in some subjects. The results indicate that eccentric rotation is a valuable method to test for bilateral otolith asymmetries. The method can be applied to preflight tests of astronaut candidates for susceptibility to spacesickness. It is also offered for clinical evaluation of unilateral otolith impairments.

Influence of proprioceptive information on space orientation on the ground and in orbital weightlessness.

Conscious space orientation depends on afferent information from different sense organs including the labyrinth, the eyes, tactile cues from the skin, joint receptors, muscle spindles, tendon organs and possibly viscera. An important role is played by impulses from the cervical position receptors in interaction with concomitant information from the otolith system. In order to isolate the effect of cervical position receptors from that of the otolith system, space experiments in orbital weightlessness and in parabolic aircraft flight were performed. It was found that stimulation of the neck receptors in weightlessness markedly influences the perception of the subjective vertical and horizontal and in addition has a weak effect on ocular torsion.

Dorsal light response and changes of its responses under varying acceleration conditions.

In order to improve our understanding about functions of the gravity sensors, we have conducted four experiments in goldfish: 1) To define the effect of visual information influx on the static labyrinthine response, the dorsal light response (DLR) which had been proposed by von Holst as a model for postural adjustment in fish was reexamined with a newly designed, rotatory illumination device. The fish responded to illumination from the upper half of the visual field and a narrow range around 180 degrees of the lower half visual field. The maximal tilting angle of normal fish was about 40 degrees under horizontal illumination. 2) Under the changes of the gravito-inertial force level produced by a linear sled, the threshold of the gravity sensors was determined from postural adjustment responses. 3) Under hypogravic conditions during the parabolic flight of an airplane, the light-dependent behavior was investigated in intact and labyrinthectomized goldfish. 4) As one of the most likely candidates of the neural centers for the DLR, the valvula cerebelli, which receives its visual information not through the optic tectum but through the pretectal areas, is confirmed by the brain lesion experiments.

Rotation speed of labyrinthectomized fish during short-duration weightlessness.

This study used blind unilaterally labyrinthectomized goldfish of 5 to 15 cm body length. These goldfish were flown in parabolic flights to temporarily effect the loss of the second vestibular apparatus. Flights took place between 1 and 72 h after the operation. Attitude in 3 axes was recorded on video and analyzed from single-frame pictures for speed and direction of rotation about the roll (fish's body longitudinal) axis. Labyrinthectomy resulted in a rotation pattern consistent with literature under normal Earth-G conditions. Under diminished G-influence, the rotations, contrary to our expectation, did not stop, but, rather, increased in speed by a factor of 2 to 4. The direction of rotation did not change. The fish readapted to the low-G environment rapidly and returned to the rotation speeds observed before entry into the parabolas during the 5 to 7 s of parabola duration. Current theories for the generation of adaptation are discussed and their merits in explaining the experimental data are compared.

Effects of rectilinear acceleration, caloric and optokinetic stimulation of human subjects in the Spacelab D-1 mission.

A set of vestibular experiments was performed during the course of the German Spacelab D-1 mission from 30 October to 6 November 1985 by a consortium of experimenters from various european countries. Similar to the Spacelab SL-1 mission all of the scientific crew members were theoretically and practically trained for the experiments. Baseline measurements for all tests were collected 113, 86, 44, 30 and 18 days prior to the mission and compared with data taken inflight, on the landing day and the consecutive 7 to 14 days. The hardware comprised mainly a motordriven accelerating platform, the SPACE SLED, and the vestibular helmet, a multi-purpose instrument in support of a variety of vestibular experiments including air-calorisation of the ears, optokinetic stimulation pattern presentation and optical and nystagmographic recording of eye movements. Measurements of the threshold for the perception of detection of whole body movement did not reveal any dramatic changes in the 2 measured axes inflight when compared to preflight values. Early postflight values show a significantly elevated threshold for all axes in 3 out of 4 subjects. The caloric nystagmus, already found during the SL-1 mission, was confirmed on all three tested subjects during the D-1 mission. It's amplitude and in some instances it's direction were influenced by horizontal acceleration on the SLED. The amplitude of optokinetic nystagmus increased when subjects were allowed to free-float over that seen when subjects were fixed. Stimulation of the neck receptors by roll movements of the body against the fixated head resulted in illusory object motion to the contralateral side. Torsional movements of the eyes during such neck receptor stimulation was present inflight and postflight, while it had not been observed preflight. Most results point to a reduction of otolithic effects in favour of visual and proprioceptive influences for spatial orientation.

The European vestibular experiments in Spacelab-1.

A series of experiments were performed in the Spacelab-1 mission on November/December, 1983, pre-, in-, and postflight. These experiments covered various aspects of the functions of the vestibular system, the inflight tests comprising threshold measurements for linear movements in three orthogonal axes, optokinetic stimulation, vestibulo-ocular reflexes under linear and angular accelerations, caloric stimulation with and without linear accelerations; pre- and postflight tests repeated the inflight protocol with the addition of subjective vertical and eye counter-rotation measurements using a tilt table. One of the most surprising and significant results was the caloric test: strong caloric nystagmus on the two subjects tested was recorded inflight; this was contrary to what was expected from Barany's convection hypothesis for caloric nystagmus.