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Biomedical subjects

M Hashiba

Publications and source records attributed to M Hashiba.

At least 37 records · Page 2Linked to original sources
PubMed1996

Inhibitory activity of clarithromycin on biofilm synthesis with Pseudomonas aeruginosa.

Inhibitory activity of clarithromycin (CAM) on biofilm synthesis with Pseudomonas aeruginosa was observed both qualitatively and quantitatively. Using scanning electron microscopy it was seen that biofilms on a Teflon sheet with CAM decreased markedly in a dose-dependent manner as compared with a control Teflon sheet without CAM. The quantity of hexose, a key biofilm ingredient, decreased with increasing concentrations of CAM, even though CAM has no direct bactericidal activity against P. aeruginosa. The results indicated that CAM inhibits the synthesis of biofilm via inhibition of polysaccharides synthesis. This inhibition of CAM was confirmed at 10 micrograms/ml or higher, levels attainable in human tissue at clinical dosage. We concluded that CAM has a considerable potential in the treatment of intractable infection caused by biofilm.

Anti-Bacterial Agents↗
PubMed1996

Inhibitory effect of roxithromycin on biofilm formation of Pseudomonas aeruginosa.

Biofilm formed by bacteria has recently has been shown to be involved in making infectious diseases intractable. We indirectly measured and evaluated the inhibitory effect of roxithromycin (RXM) on biofilm formation on the inside of a plastic test tube by determining the number of living bacteria in the biofilm. As a result, RXM was found to inhibit biofilm formation even though it does not have antimicrobial activity against Pseudomonas aeruginosa. In addition, this inhibitory effect on biofilm formation was observed at in vivo concentrations which are possible in clinical use of RXM. Thus, there is a possibility that RXM is effective against infectious otolaryngological diseases when biofilm formation is likely to be pathologically involved, even if the detected bacteria are not sensitive to the drug.

Anti-Bacterial Agents↗
PubMed1996

Efficacy of long-term administration of clarithromycin in the treatment of intractable chronic sinusitis.

Long-term erythromycin therapy has been reported as effective in the treatment of various chronic respiratory diseases, including chronic sinusitis. We investigated the clinical efficacy of long-term administration of the erythromycin derivative clarithromycin (CAM) in intractable cases of chronic sinusitis. Forty-five adult patients were treated with dosages of 400 mg/day for 8 to 12 weeks. The results were as follows. i) Improvement of symptoms and rhinoscopic findings was noted in 71.1% of the patients. ii) For periods of up to 12 weeks, clinical efficacy depended upon the duration of treatment. Administration for more than 12 weeks might further improve clinical results. iii) No significant side effects were noted during the course of CAM treatment. On the whole, CAM was at least as effective as erythromycin in the treatment of chronic sinusitis.

Adolescent↗
PubMed1996

Smooth pursuit eye movements elicited by pseudorandom target motion in normal subjects.

The purpose of this study was to determine which test conditions are appropriate for clinical examination of predictive control ability in smooth pursuit eye movements (SPEM). A combination of sinusoidal and pseudorandom target motion was employed to examine SPEM. Pseudorandom waves were generated by summing sinusoidal components spaced at 0.05 Hz intervals over three frequency ranges: 0.05 to 0.5 Hz, 0.05 to 1 Hz and 0.05 to 1.5 Hz. The peak amplitude of the resultant target waveform was set at 30 degrees. Testing was performed with 8 normal subjects. The results indicate a SPEM gain of 0.9 for 0.05-0.5 Hz, 0.7 for 0.05-1 Hz and 0.3 for 0.05-1.5 Hz. It is concluded that the pseudorandom wave of 0.05 to 1 Hz in frequency range is most suitable for clinical use.

Adult↗
PubMed1996

Voluntary suppression of caloric nystagmus under fixation of imaginary or after-image target.

Voluntary suppression of caloric nystagmus was investigated in 10 normal subjects under the following three conditions; i) with visible, earth-fixed target in the dark ("visual"), ii) with imaginary target in the dark ("imaginary"), and iii) an after-image on the fovea in the dark ("after-image") Subjects were able to suppress caloric nystagmus with a visible target very well, but they could only partially suppress caloric nystagmus with imaginary target and with after-image. The degree of suppression in the "imaginary" and "after-image" conditions was significantly less than that in "visual", but was not zero. These results are consistent with those of many reports about visual-vestibular interaction and VOR voluntary modification during rotation, and suggest that smooth pursuit eye movements (SPEM) system plays a major role in visual suppression during caloric nystagmus.

Adult↗
PubMed1996

Non-visually induced smooth pursuit eye movements using sinusoidal target motion.

Non-visually induced smooth pursuit eye movements (SPEM) were assessed in 8 healthy subjects. Targets were the subjects finger tip movements as somatosensory stimulus and a moving sound source as acoustic stimulus. Horizontal sinusoidal target movements were provided at an amplitude of 15 degrees and frequencies of 0.2, 0.4 and 0.8 Hz. In comparison with conventional visually-induced SPEM, low gain and phase lead were observed, particularly at higher frequency target movements. There was considerable inter-individual variability in the non-visual SPEM performance. A positive correlation between the gains of somatosensory and acoustic SPEM was observed in each subject. We suggest a common SPEM generator, including predictive control for the non-visual SPEM and to some extent for the visual SPEM.

Acoustic Stimulation↗
PubMed1996

Influence of foveal afterimage on non-visually induced pursuit eye movements.

Smooth pursuit eye movements (SPEMs) were measured during trials with an acoustic target, a somatosensory target (finger tip), and an imaginary target. Under these non-visual conditions the induced SPEMs were investigated both with and without a foveal afterimage. Ten normal subjects were examined. Considerable inter-individual differences were observed in performance of the non-visual SPEMs. However, the presence of an afterimage did not influence SPEMs during acoustic or somatosensory pursuit. It is concluded that the capacity for "visualization" may not involve the ability for non-visual SPEMs. As in imaginary target condition the subjects could not elicit SPEM without the afterimage, clearly the memory of target motion alone cannot generate SPEMs. The afterimage may help the subject to convert the memory of target motion into the perception of virtual target motion.

Acoustic Stimulation↗
PubMed1996

Influence of superimposed optokinetic stimulus on smooth pursuit eye movements elicited by sinusoidal spot target oscillation.

In 6 healthy subjects, smooth pursuit eye movements (SPEMs), elicited by sinusoidal spot target oscillation, were measured against three different backgrounds: dark, stationary texture (texture), and texture background movement in-phase with the spot target (coupled). Spot-target oscillation frequencies ranging between 0.2 to 1.6 Hz and peak velocities ranging between 19 to 75 degrees/s were employed. SPEM gain did not differ significantly among the three backgrounds below 0.8 Hz. However when at 1.6 Hz it responded to a peak velocity of 75 degrees/s, the gain for the "coupled" background condition was greater than that for the "dark" condition, which in turn was greater than the gain for "texture". However, SPEM phase delays were found to be similar for the three background conditions. Since the responses during "coupled" and "texture" backgrounds are most likely elicited by rapid-rise optokinetic reflex (OKR) interaction it can be concluded that SPEMs and the rapid-rise OKR system have the same latency (response) time.

Adult↗
PubMed1995

Imaginary gaze effects on eye movements induced by linear acceleration: involvement of vestibular induced smooth pursuit eye movement.

We investigated smooth eye movements elicited i) by linear acceleration in a space-fixed imaginary gaze condition (smooth component of eye movement induced by linear motion: LSEM) and ii) during acoustic pursuit of a moving sound source (smooth component of eye movement induced by acoustic pursuit of a sound source: SSPEM). The two conditions were examined using the same test subjects. LSEM and SSPEM performance was found to be positively correlated across the subject population. From the comparison of LSEM and SSPEM we propose the following hypothesis: LSEM consists not only of a pure translational vestibular-ocular reflex (tVOR) component but also of a component based on the perception of otolithic information. Accordingly, this second component is instrumental in the pursuit of an imaginary visual target during linear self-motion.

Acceleration↗
PubMed1995

[Quantitative analysis of smooth pursuit eye movement].

Abnormalities of smooth pursuit eye movement (SPEM) have been estimated, mainly using the wave form on an electro-oculogram, in a qualitative way. Many methods for quantitative analysis of SPEM have been designed, though most are still uncommon in present clinical use. Using a personal computer, we developed a method of automatic quantitative analysis of ocular tracking eye movement recorded by electro-oculography (EOG). The design concept of this method is based on the observation that eye movement during ocular tracking consists of two different kinds of eye movements, one is SPEM and the other is saccade. The combination of SPEM and saccade (composite eye movement: CEM) commonly appears during ocular tracking. These two kinds of eye movement are essentially different not only in behavior but also about involved neural pathway in the central nervous system. From this point of view, we believe that the two kinds of eye movements involved in ocular tracking should be evaluated separately. The analysis method is outlined as follows. A horizontal sinusoidally moving visual target was employed to elicit ocular tracking eye movements. The test frequencies were set at 0.1, 0.2, 0.4 and 0.8Hz, and the amplitude of target motion was 15 deg at each frequency. The 20 seconds of eye movement data measured by EOG were fed into the computer through a digital-analog converter for further analysis. Using our original saccade detection algorithm, based on the physiological behavior of saccades, the saccadic components were detected and removed from the eye movement wave. The remaining parts, fragments of SPEM, were connected by means of interpolating defective parts. The reconstructed wave was a slow cumulative eye position curve (SCEP). Sinusoidal target motion, CEM and SCEP were processed by the FFT (Fast Fourier Transformation) method. Bode plots were applied to summarize the gain and phase of responses to SCEP and the target motion wave. These processes enable us to estimate abnormalities of SPEM such as low gain, abnormal phase shift and large trends in tested duration. We conclude that the method described here is useful for quantitative estimation of SPEM in clinical neuro-otological examinations.

Adult↗
PubMed1993

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.

Acceleration↗
PubMed1991

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.

Acceleration↗
PubMed1991

Effect of water immersion on post-rotatory and caloric nystagmus.

Caloric nystagmus and post-rotatory nystagmus were recorded with and without head-out water immersion. As water immersion reduces body weight by about 90% owing to buoyancy, it decreases somatosensory inputs. Thus water immersion can be used to simulate a weightless environment. Caloric nystagmus was enhanced significantly by water immersion; however, post-rotatory nystagmus was not. These findings demonstrate that caloric nystagmus is easily affected by water immersion which decreases somatosensory inputs, but that post-rotatory nystagmus is not.

Caloric Tests↗
PubMed1991

[Severe dyspnea caused by vecuronium bromide administration for priming and precurarization].

Vecuronium bromide 1mg was injected intravenously for priming or precurarization in 42 cases. Apparent dyspnea was observed in 2 cases. The doses of vecuronium bromide in these 2 cases, 0.018 and 0.016 mg.kg-1, respectively were the same and less than those in the other 40 cases (0.018 +/- 0.003 mg.kg-1, mean +/- SD). Although respiratory sparing effect of vecuronium bromide is expected, intensive respiratory assist should be taken at the time of priming or precurarization with the drug.

Aged↗
PubMed1987

A trial of automatic kidney detection in a dynamic renal study.

We developed an automatic kidney detection procedure designed to do away with extraneous margins such as the liver or spleen while leaving the kidney margins intact using Laplacian operations and concurrence calculations. We evaluated the detectability of kidneys using our procedures and found that the renal margins were successfully detected in 84 cases of 100 subjects (84%) including 176 kidneys out of a total of 198 kidneys (89%). It was shown that as the renal function decreased the detectability of the renal margin decreased. In eight cases (16 kidneys) out of 9 patients who later resultantly received hemodialysis even manual settings of the renal ROI were very difficult. After excluding these 8 cases the detectability was 92% for all the cases and 95% for the kidneys. It was our conclusion that this method is sufficient for clinical application.

Humans↗