Protective effects of influenza A (H1N1) pandemic 2009 vaccination against the onset of influenza-like illness and asthma exacerbation in Japanese children.

BACKGROUND: Vaccination against influenza A(H1N1)pdm09 in Japan started in October 2009. Children with asthma are considered as a high-risk group and are recommended to preferentially receive the vaccine. OBJECTIVE: To identify the clinical effects of vaccination in Japanese children with and without asthma. METHODS: We conducted a cross-sectional, questionnaire-based survey to compare vaccination rates, vaccine effectiveness against physician-diagnosed influenza A infection (PDIA), and consecutive asthma exacerbations between children with and without asthma. RESULTS: Of the 460 children included in this study, those with asthma had higher vaccination rates (46.5%, 67/144) than those without asthma (30.4%, 96/316). Influenza A infections were diagnosed in 28 of 163 vaccinated children (17.2%) compared to 164 of 297 unvaccinated children (55.2%, p < 0.001). Comparison of positive influenza diagnosis rates between vaccinated and unvaccinated children with and without asthma showed that unvaccinated children with asthma had an elevated odds ratio (13.235; 95% confidence interval [CI], 5.564-32.134) and that treatment for asthma exacerbations was needed in a larger proportion of unvaccinated children. Vaccine effectiveness against PDIA was 87% (95% CI, 78-93%) overall, 92% (95% CI, 81-96%) in children with asthma and 81% (95% CI, 63-91%) in children without asthma, respectively. CONCLUSIONS: The administration of an inactivated, split-virus, non-adjuvanted monovalent A(H1N1)pdm09 vaccine during the pandemic period reduced the number of physician-diagnosed influenza A infections and asthma exacerbations in children with asthma. Therefore, we strongly recommend that high-risk children with a history of asthma receive vaccines during pandemics.

[Decline of monocular contrast sensitivity during binocular fixation].

To investigate binocular single vision, we examined monocular contrast sensitivity during binocular fixation by changing the intervals between the beginning of fixation and a probe stimulus, within 10 seconds. Monocular contrast sensitivities were quite stable within 1s of the interval delay in both eyes, but they were reduced in either eye if the interval delay was more than 1s (Experiment 1). In Experiment 2, a similar stimulus was monocularly presented. In this case, decline of contrast sensitivity was not observed in either eye. In Experiment 3, when the stimulus was interrupted briefly before the probe presentation, the contrast sensitivity was recovered. These results suggest that after prolonged viewing the binocular system does not sustain either eye sensitivity equally unless there is interruption of the binocular stimulation.

Effects of visually simulated roll motion on vection and postural stabilization.

BACKGROUND: Visual motion often provokes vection (the induced perception of self-motion) and postural movement. Postural movement is known to increase during vection, suggesting the same visual motion signal underlies vection and postural control. However, self-motion does not need to be consciously perceived to influence postural control. Therefore, visual motion itself may affect postural control mechanisms. The purpose of the present study was to investigate the effects of visual motion and vection on postural movements during and after exposure to a visual stimulus motion. METHODS: Eighteen observers completed four experimental conditions, the order of which was counterbalanced across observers. Conditions corresponded to the four possible combinations of rotation direction of the visually simulated roll motion stimulus and the two different visual stimulus patterns. The velocity of the roll motion was held constant in all conditions at 60 deg/s. Observers assumed the standard Romberg stance, and postural movements were measured using a force platform and a head position sensor affixed to a helmet they wore. Observers pressed a button when they perceived vection. Postural responses and psychophysical parameters related to vection were analyzed. RESULTS: During exposure to the moving stimulus, body sway and head position of all observers moved in the same direction as the stimulus. Moreover, they deviated more during vection perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion. The postural movements also fluctuated more during vection-perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion, both in the left/right and anterior/posterior directions. There was no clear habituation for vection and posture, and no effect of stimulus type. CONCLUSION: Our results suggested that visual stimulus motion itself affects postural control, and supported the idea that the same visual motion signal is used for vection and postural control. We speculated that the mechanisms underlying the processing of visual motion signals for postural control and vection perception operate using different thresholds, and that a frame of reference for body orientation perception changed along with vection perception induced further increment of postural sway.

Neuroradiologic findings in Sotos syndrome.

Sotos syndrome is a well-known anomaly syndrome characterized by overgrowth, characteristic facial gestalt, and developmental delay, and haploinsufficiency of the NSD1 gene has been revealed as one of the major genetic causes. However, there have been only a few reports on neuroradiologic findings by computed tomography (CT) or magnetic resonance imaging (MRI), and functional examination of the brain has not been reported. We examined three cases with typical Sotos syndrome, which also were confirmed by genetic analysis with a specific probe for the NSD1 gene. The results of MRI showed the characteristic features that have been reported previously. The findings obtained by using single-photon emission computed tomography and magnetic resonance spectroscopy suggested an association between mental delay and behavioral tendency in Sotos syndrome and immaturity in frontal brain function.

Transient lesion in the splenium of the corpus callosum in acute cerebellitis.

We report the reversible magnetic resonance imaging (MRI) findings in a 2-year-old girl with acute cerebellitis. The high signal intensity in the cerebellum was obvious on diffusion-weighted images, and the splenium of the corpus callosum also showed high signal intensity on T2-weighted images and on diffusion-weighted images. The lesion in the splenium quickly returned to normal 72 hours later, whereas the hyperintensity in the cerebellum persisted for 1 week until clinical improvement was achieved. The findings in our patient suggested the particular vulnerability of the splenium of the corpus callosum compared to other regions and the importance of the MRI examinations including diffusion-weighted images in the early stage of encephalitis.