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Biomedical subjects

Y Koike

Publications and source records attributed to Y Koike.

463 records · Page 26Linked to original sources
PubMedDate not supplied

Computer analysis of fixation-suppression of caloric nystagmus.

Effects of the ocular fixation upon caloric nystagmus were quantitatively analyzed and compared between normal subjects and patients by using a PDP 11/40 computer. The slow-phase velocity was the best parameter to separate normal from abnormal visual fixation. An analysis of caloric nystagmus with failure of fixation-suppression (FFS) made it possible to classify patterns of FFS into three types. The combination of FFS with impairment of the optokinetic responses provides a useful diagnostic tool with respect to lesions located between the brain stem and the cerebellum.

Adult↗
PubMedDate not supplied

Changes in ambulation and drinking behavior related to stroke in stroke-prone spontaneously hypertensive rats.

In order to elucidate the behavioral changes related to stroke, ambulatory activity and water drinking were observed in stroke-prone spontaneously hypertensive rats (SHRSP). Age matched male SHRSP and Wistar Kyoto rats (WKY) were subjected to a 12 hour light and dark alternation cycle. Ambulation and drinking activity counts were determined simultaneously with an Ambulo-Drinkometer. Before stroke, ambulation and drinking activity counts in the dark phase (82%) were higher than those in the light phase (18%). Both parameters were well synchronized with the light and dark alternation cycle. With aging, daily ambulation decreased while daily drinking activity increased in SHRSP and WKY. Daily ambulation and drinking activity in 15 and 30 week old SHRSP were greater than those of WKY. It was demonstrated with an Ambulo-Drinkometer that SHRSP undergo specific behavioral changes before the onset of stroke. For instance, the 40-60 week old SHRSP showed significant individual variation in both ambulation and drinking activity. This desynchronization with the light and dark alternation cycle was followed by stroke. Twenty seven autopsies showed 11 cerebral infarctions, 10 cerebral hemorrhage and 6 cerebral hemorrhage with infarctions to be the causes of death.

Activity Cycles↗
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Application of inverse filtering for detecting laryngeal pathology.

Inverse filtering analysis was performed on acoustic speech samples of the vowel sound "ah" produced by ten selected patients and ten normal adults. The inverse filter output signal is the residue obtained by automatically extracting the effects of the supraglottal structure from the acoustic speech signal. For normal speakers, the residue consists of a series of rather sharp periodic spikes having low amplitude noise between periods. For pathological voices, the residue consists of lower amplitude, less sharp spikes having higher amplitude noise between periods. Comparisons between the acoustic speech waveforms and the residue signals illustrate the superiority of the residue signal for detecting irregularity, and thus suggests the feasibility of applying inverse filtering as an aid to laryngeal diagnostics.

Acoustics↗
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Acoustic measures for detecting laryngeal pathology.

Perturbations in the fundamental pitch and in the peak amplitude of the acoustic signal derived with a contact microphone system were investigated for the purpose of developing useful measures for the detection of laryngeal pathology. Sixty-three patients with various laryngeal pathologies and 31 normal subjects were studied. In 14 cases high speed motion pictures of the larynx were taken in order to examine the physiological mechanisms giving rise to the perturbations in the acoustic signal. The collected acoustic data were statistically processed, and a "critical ellipse" was computed for each subject category. The significance of the concept of a "normal standard" was discussed. It was pointed out that the physiological mechanisms for the acoustic perturbations were rather complicated and that many physiological aspects may have to be taken into account. The need for basic physiological research in relation to pathologic speech production was emphasized.

Adolescent↗
PubMedDate not supplied

Visual suppression of caloric nystagmus and optokinetic responses in cats.

Previously it was reported that loss of visual suppression (VS) was accompanied by disturbance of optokinetic nystagmus (OKN) in monkeys with lesions at the flocculus. In the present experiment with cats, OKN was investigated after inflicting lesions on either superior colliculus (SC) or inferior olive (IO), both of which are considered to be the main prefloccular relay nuclei to mediate visual signals to the flocculus. VS of caloric nystagmus was recognized in all the IO-lesioned cats and OKN remained normal except in one cat. After the left SC lesions, loss of VS was evidently revealed and optokinetic stimuli produced directional preponderance to the left with diminished responses to the right in 7 of 9 cats. The present findings suggest that the SC may be an important relay nucleus to the flocculus in conveying visual signals responsible for VOR gain.

Animals↗
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The fast-phase velocity of optokinetic nystagmus in central nervous system disorders.

The fast phase of optokinetic nystagmus (OKN) in patients with central nervous system (CNS) disorders was quantitatively evaluated using a micro-computer. The relationship between peak velocity of the fast phases of OKN (velocity(p] versus amplitude was recognized to be best fitted to an exponential equation, i.e., velocity(p) = K(1-exp[-amplitude/L]). In patients with lesions in thalamus, midbrain, or pons, the velocity(p) was significantly reduced, whereas in patients with lesions in the medulla or the cerebellum, it was normal. The directional asymmetry of velocity(p) toward the lesion side indicated that the velocity(p) toward the intact side was significantly reduced as compared with that toward the lesion side in patients with lesions in the thalamus or midbrain, whereas in patients with lesions in the pons, the velocity(p) toward the lesion side had decreased significantly as compared with that toward the intact side. Thus the quantitative evaluation of velocity(p) may provide some important information on the mapping of lesions in patients with CNS disorders.

Adult↗
PubMedDate not supplied

Mucosal blood volume and oxygen saturation in the human vocal fold.

With a newly developed spectrophotometric analyzer we were able to measure hemoglobin (Hb) concentration and its oxygen saturation in the human vocal and ventricular folds. Studies were made on 30 subjects including 18 normal controls. In laryngomicrosurgery under general anesthesia, measurements were made with a fiber probe touching the laryngeal mucosa. Results were as follows: In normal mucosa of the vocal fold, the mean value of IHb was 40 and the ISO2 was 55, while in that of the ventricular fold, the mean values were 74 and 56, respectively. Thus, in spite of the influence of general anesthesia, the mucosal blood volume was lower in the vocal fold than in the ventricular fold. The mean value of IHb was 30 in the vocal fold polyps, 122 in the vocal fold nodule, 43 in the polypoid degenerations, 17 in the vocal fold cyst, 62 in the granuloma, 6 in the sulcus vocalis and 19 in the hyperkeratoses. This method is considered useful for objective and quantitative analysis of pathological conditions in the vocal fold.

Adult↗
PubMedDate not supplied

Frequency specificity of amplitude-modulation-following response detected by phase spectral analysis.

To investigate the frequency specificity of steady-state responses elicited with a sinusoidally amplitude-modulated tone (amplitude-modulation-following response, AMFR), AMFR at different carrier frequencies were examined in 15 subjects with normal hearing, 12 patients with abrupt high-frequency hearing loss, 5 patients with low-frequency hearing loss and 1 patient with mid-frequency hearing loss. The stimulus was a sinusoidally amplitude-modulated tone with a modulation frequency of 40 Hz and modulation depth of 95%. Carrier frequencies were from 250 to 4000 Hz in normal subjects and from 250 to 8,000 Hz in hearing-impaired subjects. Fridman's phase spectral analysis was conducted for automatic detection of response. The thresholds of AMFR were distributed within 30 dB nHL at all carrier frequencies in normal subjects. In the hearing-impaired subjects, AMFR thresholds were between 0 and 25 dB above the behavioral threshold at all carrier frequencies. The threshold patterns of AMFR detected by phase spectral analysis very closely resembled the corresponding audiogram patterns in all types of hearing impairment. AMFR is thus shown to have a very good frequency specificity.

Acoustic Stimulation↗
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Speech audiometric trial using synthetic vowels produced with DEC-talk.

A speech audiometric trial is described for testing the degree of hearing loss and its pathogenesis. Test vowels and distorted speech sounds were synthesized with DECtalk for use in speech audiometric tests. Results showed that 100% articulation can be obtained with undistorted synthesized vowels, while reasonable articulation scores can be obtained with distorted synthetic speech signals. This method could solve some of the problems inherent in use of recorded natural Japanese speech sounds as acoustic stimuli during otological examinations.

Audiometry, Speech↗
PubMedDate not supplied

A case of abdominal cystic lymphangioma: cobweb appearance on ultrasonography.

A case of abdominal cystic lymphangioma is described. Our sonographic examination showed a large multilocular cyst with a cluster of honeycomb cysts revealing a cobweb appearance, which correlated with the pathologic specimen, and revealed characteristics of the disease. Sonographic appearance may be helpful in differentiating abdominal cystic lymphangioma from other multilocular cystic tumors.

Abdominal Neoplasms↗
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Cytologic characteristics and origin of naked nuclei in breast aspirate smears.

To elucidate the origin of "naked nuclei" in breast aspiration smears, 17 cases of fibroadenoma were studied by light and electron microscopy. The ATPase reaction was also studied at both levels. The aspirates contained two types of naked nuclei: denuded degenerated nuclei and oval to spindle-shaped nuclei with very scanty cytoplasm. The cytoplasm of the latter was rich in free ribosomes and rough-surfaced endoplasmic reticulum but was devoid of cytoplasmic filaments and dense bodies. These cells were negative for ATPase activity. Stromal cells, not myoepithelial cells, characteristically demonstrated such cellular features in the aspirates and tissue sections studied. We conclude that most naked nuclei are derived from stromal cells.

Adenofibroma↗