PURPOSE: The head-mounted display (HMD) has produced conflict between visual and vestibular stimuli because the HMD image does not move with the head motion of the wearer. The HMD can show binocular parallax three-dimensional (3D) images, in which vergence and accommodation conflict. Thus, the HMD may affect the normal visual/vestibular functions. We attempted to develop a system that makes possible the measurement of torsional eye movements, vergence eye movements, and pupillary responses of the HMD wearer. METHODS: Our apparatus is composed of two infrared CCD cameras installed in the HMD. Iris images produced by these cameras are analyzed by a personal computer using free software. Further, a third camera fixed on the HMD projects an image of the view as the subject sees it, via video tape recorder or frame memory to the HMD. Images can be stored, replayed, or frozen. RESULTS: Our system can measure torsional eye movement with 0.20 degrees resolution every 1/30 (or 1/60) seconds even though the pupil size alternates during measurement. Binocular eye movement and pupillary response are also measured. CONCLUSION: A system was developed which can be used for assessment of the effect of 3D HMD on the visual system. A third camera coupled with HMD can control visual stimulus independently of head motion (vestibular stimulus).

Eye Movements↗

PubMedDate not supplied

Adrenoceptors affect accommodation by modulating cholinergic activity.

In an attempt to clarify the functional role of adrenoceptors in accommodation, the effects of various adrenergic agents on the state of accommodation were studied. Fifty-two emmetropic, visually normal subjects (24.6 +/- 0.42 years old) participated in this study. Using an infrared optometer, the far and near points of accommodation were measured by a quasistatic method. Tonic accommodation and accommodative adaptation were also investigated. All these parameters were measured before and after topical application of various adrenergic agents. Both bunazosin hydrochloride (0.1%) and phenylephrine hydrochloride (5%) had no effect on tonic accommodation and accommodative adaptation. However, bunazosin hydrochloride increased the near point of accommodation. Timolol maleate (0.5%) and isoproterenol hydrochloride (3.0%) did not affect tonic accommodation. Isoproterenol hydrochloride evoked a hyperopic shift of the far point of accommodation by 0.23 +/- 0.42 diopters (D). Additionally, accommodative adaptation was increased by timolol maleate (0.36 +/- 0.62 D) and decreased by isoproterenol hydrochloride (0.18 +/- 0.48 D). These results indicate that both alpha and beta adrenoceptors affect accommodation. Activation of alpha adrenoceptors increased the near point of accommodation and activation of beta adrenoceptors decreased accommodative adaptation, which suggests that activation of adrenoceptors may modify parasympathetic activity; hence, affecting the state of accommodation.

Accommodation, Ocular↗

PubMedDate not supplied

Aneurysmal bone cyst of the temporal bone: magnetic resonance imaging as a valuable tool for preoperative diagnosis.

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Bone Cysts, Aneurysmal↗

PubMedDate not supplied

Subcutaneous seeding of small hepatocellular carcinoma after fine needle aspiration biopsy.

Ultrasonically guided fine needle (21 gauge) aspiration biopsy (FNAB) was performed on a patient with a hepatocellular carcinoma (HCC) measuring 1.5 x 1.5 cm in segment VI of the liver. The tumour was located just beneath the liver surface. Subsegmentectomy of segment VI was performed. Twelve months after the biopsy and 10 months after the operation, levels of alpha-fetoprotein (AFP) and protein induced by Vitamin K absence or antagonist-II (PIVKA-II) increased gradually without any evidence of recurrence of HCC in the liver. Thirteen months after the biopsy, the patient palpated a hard subcutaneous nodule 1.5 cm in diameter in the right lower anterior chest wall at the insertion site of the biopsy needle. A subcutaneous tumour was excised and histological examination revealed moderately differentiated HCC. The levels of AFP and PIVKA-II normalized thereafter. These tumour markers were therefore useful for diagnosing the subcutaneous nodule as a metastatic HCC. The patient is currently doing well without further recurrence of HCC or needle-tract seeding 23 months after subsegmentectomy and 11 months after excision of the subcutaneous tumour.

Aged↗

PubMedDate not supplied

Significance of kallikrein-kinin system in otitis media with effusion.

Significance of the kallikrein-kinin system in the pathogenesis of otitis media with effusion (OME) was evaluated by prekallikrein level, kallikrein activity, and concentration of high molecular weight (HMW) kininogen in 45 middle ear effusions (MEEs, 38 serous and seven mucoid). All MEEs had varying prekallikrein levels (73.1 +/- 127.5 relative fluoro units [RFU]), and the mean value in serous effusions (82.2 RFU) was much higher than that in mucoid effusions (23.0 RFU). Hydrolytic activity of kallikrein in serous effusions was 18.0 +/- 27.9 RFU, and was significantly higher than that in mucoid effusions (8.0 +/- 4.2 RFU, p less than 0.05). Concentration of HMW kininogen in serous effusions was 51.2 +/- 72.77% of plasma value, but it could not be detected in any mucoid effusions. Analysis of protein composition by polyacrylamide gel electrophoresis indicates that plasma protein that has leaked into the middle ear is a major component of MEEs. The kallikrein-kinin system would be active in serous effusions, and liberated bradykinin enhances vascular permeability in the middle ear mucosa, leading to profuse plasma leakage, which characterizes the component of serous effusions. On the other hand, this system would almost be consumed in mucoid effusions.

Adult↗

PubMedDate not supplied

Ultrastructure of mucous blanket in otitis media with effusion.

We used transmission electron microscopy to study the mucous blanket of the promontory from children with otitis media with effusion. The vast majority of the epithelial cells were secretory, and the rest were ciliated. The mucous blanket consisted of the electron-lucent periciliary fluid and the mucous layer. In the mucous layer, two layers were identified: an inner layer with migrating cells, and an outer layer with specks. Moreover, there was a lucent zone over the nonciliated surface that was as high as the microvilli. The thickness of the periciliary layer was predominantly as great as that of the ciliary tips, which just make contact with the mucous layer; however, the mucous layer occasionally penetrated into the periciliary space. These findings indicated that there is a mucociliary dysfunction in the middle ear caused by a decrease in the number of ciliated cells, and an abnormal interaction between cilia and mucus that would interfere with ciliary movement. Thus, such a system would fail to transport the mucous blanket.

Biopsy↗

PubMedDate not supplied

Evaluation of nasal passage patency after antigen and histamine challenge in guinea pigs by acoustic rhinometry.

We investigated the effects of antigen and histamine on the nasal passage patency in guinea pigs with or without nasal allergy. The change of nasal patency was measured by acoustic rhinometry and nasal airway resistance. Acoustic reflections have been used in adult humans to determine nasal cavity dimensions in terms of cross-sectional areas as a function of the distance from the nostril. In order to measure nasal cavity dimensions in guinea pigs, we modified equipment for use in humans by decreasing sound tube dimensions, increasing sampling frequency, and applying a special nosepiece. The percent change of volume, minimum cross-sectional area, and nasal airway resistance showed the largest changes at 10 minutes after antigen challenge in sensitized guinea pigs. There was a significant correlation between the individual percent change of nasal airway resistance and volume or minimum cross-sectional area. Histamine, 10(2) to 10(5) micrograms/mL, caused a dose-dependent reduction in percent change of volume in the challenged side of nonsensitized guinea pigs, but not in the opposite side. These results indicate that the noninvasive acoustic reflections technique is useful in small experimental animals, especially to assess the effect of nasal cavity dimensions after the challenge of antigen or nonspecific stimuli.

Adult↗

PubMedDate not supplied

The effect of leukotriene D4 on the patency of nasal passage in the guinea pig.

We investigated the effect of leukotriene D4(LTD4) on the patency of the nasal passage in nonsensitized and sensitized guinea pigs (GPs). The change in nasal patency was measured by acoustic rhinomanometry (AR). The change of volume from the nostril to 2 cm into the nasal cavity showed significant reduction at 30 minutes and 6 hours after instillation of LTD4 in nonsensitized GPs. These findings were also seen in nonsensitized and sensitized GPs with systemic administration of carboxyl cellulose. However, neither nonsensitized nor sensitized GP with systemic administration of benzopyren hemihydrate(ONO-1078) showed any changes in nasal patency. These results indicated that the LT was a potent medication to induce nasal obstruction of late reaction in GP.

Airway Resistance↗

PubMedDate not supplied

Acoustic rhinometry evaluation of nasal response to histamine and antigen in guinea pigs.

The effects of antigen and histamine on the changes of nasal passage patency in 112 guinea pigs with or without allergic rhinitis were evaluated by acoustic rhinometry. The percent change of volume from the nostril to 2 cm into the nasal cavity showed significant reduction of 31.10 +/- 4.11% at 10 minutes and 31.10 +/- 4.11% at 30 minutes after antigen challenge in sensitized guinea pigs. The pretreatment with ketotifen, an H1-histamine receptor antagonist as well as mast cell stabilizing drug, blocked dose-dependently the effects of antigen on those changes in volume. Furthermore, instillation of 10(4) micrograms/mL histamine reduced significantly nasal passage patency to 33.77 +/- 4.63% at 10 minutes and 42.76 +/- 3.32% at 30 minutes after challenge compared with that before challenge and ketotifen inhibited the effects of histamine, which indicated that histamine is an important mediator of allergic upper airway responses in guinea pigs. These results show that acoustic rhinometry is a useful technique to assess the nasal blockade in allergic guinea pigs.

Acoustics↗