To assess the contribution of the autonomic nervous system (ANS) to beat-to-beat (R-R interval) variations in the squirrel monkey, heart rate was analyzed after atropine, propranolol, carbachol, or isoproterenol administration, using a computer analyzing system. Heart rate variations were expressed as coefficient of variance (CV) of mean R-R interval. CV of R-R interval clearly was reduced by atropine but not by propranolol, indicating that the effect could be mediated through the parasympathetic nerve. CV of R-R interval was measured also under vestibulo-visual conflict (VVC) situation in pitch. Although CV of R-R interval increased during VVC, this variation almost was abolished after atropine administration. Monkeys with unilateral labyrinthectomy showed smaller variations than those without operation during exposure to VVC. CV of R-R interval is a useful parameter for the objective and quantitative evaluation of ANS function and may be a good indicator to demonstrate the severity of motion sickness without invasive methods.

Animals↗

PubMedDate not supplied

Measurement of arterial tracer concentrations from cardiac PET images.

OBJECTIVE: Cardiac PET imaging offers the potential capability for the noninvasive measurement of arterial input function. This capability is somewhat limited, however, because of partial volume and spillover effects. The purpose of this study was to validate arterial tracer concentration measurements using PET images by assigning a region of interest (ROI) to the left ventricle, left atrium (LA), and ascending aorta. MATERIALS AND METHODS: We selected [11C]CO and [13N]ammonia as tracers, because the activity of [11C]CO is primarily in the blood pool and that of [13N]ammonia primarily in myocardial tissue. Six [11C]CO and 11 [13N]ammonia PET scans were obtained in 17 subjects. Arterial tracer concentrations determined by PET were compared with those measured by well counting of arterial blood sampling obtained at the midpoint of each image acquisition. RESULTS: Arterial tracer concentrations as determined by LA-PET imaging correlated closely with those measured by blood sampling (r = 0.996, slope = 1.00 for [11C]CO; r = 0.841, slope = 0.974 for [13N]ammonia). Partial volume and spillover effects were minimized by assigning an ROI to the LA. CONCLUSION: Arterial tracer concentrations can be measured noninvasively with cardiac PET.

Adolescent↗

PubMedDate not supplied

Anomalous vessels in the middle ear associated with congenital anomalies of the internal carotid artery.

A case with unilateral hypoplasia of the internal carotid artery was reported. The rerouting of anomalous vessels in the middle ear, visualized by otoscopy, was demonstrated with CT and MRI. Associations with internal carotid hypoplasia, the intercarotid collaterals, both anomalous middle ear arteries and the enlarged internal maxillary artery were confirmed with MRI. MR images were helpful to diagnose not only the anomalous vessels but also the multiple anastomoses.

Carotid Artery, Internal↗

PubMedDate not supplied

Middle ear imaging using virtual endoscopy and its application in patients with ossicular chain anomaly.

Virtual endoscopy (VE) is a recently developed technique to provide a realistic surface rendering of various organs, which can be applied to the use of three-dimensional (3D) studies of several lesions. However, its advantages in otological disease have not been well investigated. In this study, we evaluated the application of VE in patients with ossicular chain anomalies. Virtual middle ear endoscopy was a time-saving method, however, we needed the appropriate technical procedures of algorithm and reconstruction spacing to generate accurate 3D images of ossicles. We obtained virtual surgical views of middle ear structures and related anomalies, and confirmed by intraoperative findings that these images were mostly compatible with the actual lesions of ossicles. VE allowed an identification of the anatomy of the ossicles and adjacent structures simultaneously. The elements of the stapedial crura were clearly visualized with VE images in 93.3% of normal ears. Pathological ossicular chain findings such as malleus or incus fixation, dislocation and disruption, except footplate fixation were investigated successfully. One possible procedure, using alterable CT value in the obtained VE images on the monitor, is proposed for further detection of fine lesions of the ossicles. These observations suggest that virtual middle ear simulations accurately represent major intraoperative findings. This technique may have an important role in preoperative planning, surgical training, and/or postoperative evaluation in otology.

Adult↗

PubMedDate not supplied

Relation between vestibular function and speech recognition in postlingually deafened adults with cochlear implantation.

Thirty-one postlingually deafened adults with 22-channel cochlear implants were evaluated preoperatively using vestibular function tests, the caloric test and stabilometry. The results of caloric response were classified into two diagnostic groups: normo- or hyporeflexia and areflexia. Stabilometric recordings were made using a computerized static posturographic platform. Between the two categories of caloric response, there was a significant difference in consonant recognition, but the recognition of vowels showed no significant difference. The results of the distance of body sway in stabilometry, but not of the area, correlated to the results of consonant recognition in speech perception tests. The degree of residual vestibular function seems to be one of the indicators influencing postoperative speech recognition by cochlear implant patients.

Adult↗

PubMedDate not supplied

Surgical strategy of cochlear implantation in patients with chronic middle ear disease.

We report 10 postlingually deafened adults in whom the electrophysical criteria for cochlear implant were fulfilled, except that they showed the following unfavorable middle ear lesions: otitis media with effusion, chronic perforative otitis media, cholesteatoma and previous radical ear operation. Staged operations for cochlear implant were performed in 8 cases, and 2 patients who had undergone radical ear operation had a single-stage operation. As a first step, one of the following was performed in each patient as surgically indicated: myringoplasty with or without mastoidectomy, mastoidectomy with reconstruction of the posterior wall of the external canal, mastoidectomy with the insertion of a ventilation tube, radical mastoidectomy or surgical cleansing of the radical cavity. From 6 months to 2.5 years after the first operation, the actual cochlear implant was performed in the second or third stage. There was no major complication as a result of electrode insertion into the cochlea and the results of speech perception in these cases were not different from those in patients with normal middle ears. In our experience, it was considered that the staged operations would enable successful cochlear implants in selected patients with pathological middle ear lesions even if they had previously been diagnosed as contraindicated for this procedure. In a case with radical ear cavity a single-stage operation could be performed when there was no cavity problem.

Adolescent↗

PubMedDate not supplied

Three-dimensional imaging of the temporal bone using a helical CT scan and its application in patients with cochlear implantation.

Recent advanced techniques for the reconstruction of three-dimensional (3D) images allow further visual recognition of the fine structures of the temporal bone. We demonstrate the advantages of reconstruction 3D imaging in helical CT scans of the normal temporal bone and in patients who have received cochlear implants. After the temporal bone was scanned in the axial plane in the helical scan mode, the data were transferred to a workstation and 3D reconstruction was performed. The normal temporal bone structures were well recognized on these 3D images. The spatial relationship between the lymphatic space of the inner ear and the electrode array is visible. This method provides a detailed anatomy of the insertion of the electrodes into the cochlea and provides precise images of electrode routes by means of varying the angles of view on the computer display. Individual electrodes could not be distinguished. The information from 3D images may be useful not only for pre-but also postoperative investigations in cochlear implantation.

Cochlear Implants↗

PubMedDate not supplied

Spontaneous DNA synthesis in tonsillar lymphocytes and its clinical implications.

Spontaneous DNA synthesis (SDS) in tonsillar lymphocytes was investigated in 58 cases by [3H]-thymidine incorporation under a certain culture condition without any mitogens. Tonsillar lymphocytes showed an extremely higher uptake of [3H]thymidine than peripheral blood lymphocytes. Cells exhibiting SDS were mainly B cells, but, however, they needed the helper functions of T cells and glass-adherent cells to synthesize DNA. SDS in tonsillar lymphocytes decreased with age and was lowest in the 21-30 year age group. SDS in cases with complications such as chronic sinusitis, nasal allergy or secretory otitis media was significantly higher than that in cases with no complications.

Adolescent↗

PubMedDate not supplied

Change in susceptibility to vestibular-visual conflict sickness in monkeys by repeated exposure.

Squirrel monkeys, susceptible to the vestibular-visual conflict sickness in pitch (with frank vomiting), were subjected to repeated exposure to pitch conflict in various modes and in a randomly mixed order (30 min daily, for 10 consecutive days). Immediately after the training, a significant decline in susceptibility was found, represented by reduced vomiting rates, reduced sickness scores, reduced salivation and improved regularity of vertical oculomotor responses. Susceptibility at the pre-training level returned when the test was repeated 10 days later. Temporary suppression of pitch conflict sickness susceptibility indicates the possibility of training crew members prior to their space flight missions to control the space motion sickness, particularly vomiting.

Animals↗

PubMedDate not supplied

Asymmetry of vertical optokinetic after-nystagmus in squirrel monkeys.

Asymmetry of vertical optokinetic after-nystagmus (OKAN) was studied in 6 squirrel monkeys. The slow-phase eye velocity (SPEV) of upward OKAN first-phase (OKAN-I) increased with increasing stimulus velocity, whereas the SPEV of downward OKAN-I diminished. The time constant of OKAN-I was shortened with the increase in stimulus speed in both directions. With a downward stimulus, the short stimulus duration failed to produce OKAN second-phase (OKAN-II) (upward slow-phase); however, with an increase in stimulus duration, the percentage appearance increased. There was no change in percentage appearance, regardless of the duration of upward stimulus. The asymmetry of OKAN-I and that of OKAN-II differed to a certain degree.

Animals↗

PubMedDate not supplied

Effect of vestibulo-cerebellar lesions on asymmetry of vertical optokinetic functions in the squirrel monkey.

The role of the cerebellar uvula and nodulus in vertical optokinetic after-nystagmus (OKAN) was studied in 4 squirrel monkeys. Aspiration ablation of the uvula and nodulus resulted in no significant change in the initial or peak gain of vertical optokinetic nystagmus (OKN) during the 24-week post-operative observation. However, the asymmetry of vertical OKAN was significantly altered. Using a protracted upward OK stimulus, slow phase-down OKAN-II, which was not seen pre-operatively, was significantly increased. In contrast, a downward OK stimulus produced little change in slow phase-up OKAN-II. Thus, the asymmetric degree of vertical OKAN-II was decreased after uvulonodulectomy. In addition, there was a post-operative reduction in the vertical oculomotor stability. When slow-phase eye velocity of OKAN was plotted along the time scale, the amplitude and frequency of the sinusoidal pattern was increased. OKAN-III and OKAN-IV were found in 50% of the monkeys after uvulonodulectomy. It is therefore thought that inhibition and directional control from the uvula and nodulus influence the stability and asymmetrical behaviour of the leaky integrator in the second order output system.

Animals↗