A possible mechanism of alpha-fluoromethylhistidine-induced increase of food intake.
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Animals↗
Biomedical subjects
H Isono
Publications and source records attributed to H Isono.
Nonlinear dielectric response of antiferroelectric liquid crystals in the smectic C alpha* phase.
Nonlinear dielectric response of antiferroelectric liquid crystals has been studied in the smectic C(alpha)* (SmC(alpha)*) phase. The linear dielectric spectrum shows a single relaxation of Debye type and its relaxation frequency is as high as one hundred kHz. The profile of the third-order nonlinear dielectric spectrum varies in complex fashion with temperature. In the vicinity of the SmA-SmC(alpha)* phase transition, experimentally obtained nonlinear spectra are well described by those calculated with phenomenological theory of Landau type. The soft mode of the SmC(alpha)* phase shows critical slowing-down near the transition temperature. In the lower-temperature region of the SmC(alpha)* phase, the contribution from the soft mode of the SmC(alpha)* phase reduces and the other relaxation mode with Debye-type spectrum appears at several hundred Hz in the nonlinear spectrum. The appearance of this low-frequency mode suggests that the cooperative fluctuation of directors over long range exists in the SmC(alpha)* phase.
Journal Article↗
Optical filters inhibiting television-induced photosensitive seizures.
OBJECTIVE: Televised images are the most common stimulus for provoking photosensitive seizures in photosensitive persons. To inhibit photosensitive seizures in photosensitive persons who do or do not have epilepsy, the authors sought nonpharmacologic methods for reducing the levels of photic stimulation of televised images. BACKGROUND: The authors found two types of pathophysiologic mechanisms (wavelength-dependent and quantity of light-dependent mechanisms) for photoparoxysmal responses (PPR). METHODS: The authors tested two different types of optical filters, one reflecting long-wavelength red light selectively, which stimulates a wavelength-dependent mechanism, and the other absorbing light in the visible spectrum evenly (neutral density filters). Inhibiting effects of optical filters were studied by conventional intermittent photic stimulation (IPS) using strobe light and novel photic stimulation using flashing cathode ray tubes (CRT). RESULTS: Both filters individually inhibited PPR insufficiently (less than 50%). Compound optical filters, composed of both types of filters, can inhibit the PPR, approximately 90% for IPS and 95% for photic stimulation with CRT. These compound optical filters do not destroy chromaticity of emissions from the television's CRT. CONCLUSIONS: These compound filters may be useful to prevent seizures induced by television in photosensitive persons.
Adolescent↗
Critical behavior of nonlinear permittivity in the smectic-A phase of chiral liquid crystals.
We study the nonlinear permittivity of chiral liquid crystals in the smectic-A (Sm-A) phase near the ferroelectric smectic-C* (Sm-C*) phase and the smectic-C(*)(alpha) (Sm-C(*)(alpha)) phase theoretically and experimentally. The third-order nonlinear permittivity epsilon(3) shows the critical behavior with the exponent of four near the Sm-C* phase and its sign depends on the order of the phase transition. In the case of the Sm-A-Sm-C(*)(alpha) phase transition, the sign inversion of epsilon(3), presumably due to the large fluctuation of order parameter, is observed near the transition temperature.
Journal Article↗
Solid state optical activity of dichalcogenides: isolation by chiral crystallization and determination of absolute configuration.
[reaction--see text] Optically active diphenyl dichalcogenides were isolated in bulk for the first time by chiral crystallization. The absolute configuration of the P-helical enantiomer of diphenyl disulfide was determined by X-ray crystallography. On the basis of this determination and considering the similarities of the Cotton effects of diphenyl diselenide and ditelluride, the absolute configuration of optically active diphenyl dichalcogenides could be assigned. Furthermore, stereochemistry of chiral crystallization could be controlled by using an optically active crystal as a seed crystal.
Chalcone↗
Influence of deteriorating ability of emotional comprehension on interpersonal behavior in Alzheimer-type dementia.
This study investigated the relationship between the ability to recognize emotion and interpersonal behavior in dementia of the Alzheimer type (DAT). After examining the validity and reliability of the Emotion Recognition Test (ERT), an improved version of the tasks used by Shimokawa et al. (2000), 100 patients with DAT underwent evaluation for general cognition using the Mini-Mental State Examination (MMSE) and emotion recognition using the ERT. Within a week of these tests being administered, ward staff rated the patients using the Interpersonal Behavior Checklist (IBC), composed of two behavior scales: indifference to interpersonal relationships and difficulties with patient treatment/management. After investigating the validity and reliability of the scales, the correlations between the MMSE, the ERT, and the two scales of the IBC were calculated. The results suggested that the MMSE did not correlate with either of the two behavior scales, while the ERT correlated significantly with both of the scales. The study results lead to the conclusion that deteriorating emotion recognition ability, rather than deterioration of general cognition, influences the indifferent and awkward interpersonal behaviors of DAT patients.
Affect↗
Effects of risperidone on event-related potentials in schizophrenic patients.
In order to examine the effects of risperidone on cognitive impairment in schizophrenia, event-related potentials (ERPs) were recorded before and after switching from conventional neuroleptics to risperidone in schizophrenic patients. ERPs were recorded during two auditory discrimination tasks (an oddball task and a distraction task) in 10 medicated schizophrenic patients during conventional neuroleptic and risperidone treatments. The amplitudes and latencies of N 100 and P300 component were measured in ERPs for target stimuli in the oddball task and in ERPs for target and novel stimuli in the distraction task. Although N 100 amplitude and latency and P 300 amplitude did not change significantly after switching the drug compared to that during conventional neuroleptic treatment, P 300 latency for target stimuli shortened significantly during risperidone treatment in both tasks, accompanied by the shortening of the reaction time in the distraction task. The P 300 latency change did not correlate with the change of the severity of psychopathology. These findings suggest that risperidone may speed the information processing in schizophrenic patients, contributing to the improvement of cognitive functions.
Adult↗
Clinical characteristics of delusional disorder.
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Aged↗
Event-related potentials and thought disorder in schizophrenia.
We examined the relationship between event-related potentials and thought disorder in schizophrenia. The subjects were 29 chronic schizophrenic patients. Thought disorder was assessed using the Comprehensive Index of Positive Thought Disorder developed by Harrow and colleagues (Harrow and Quinlan, 1985; Marengo et al., 1986). Auditory event-related potentials were recorded during a standard oddball task. The P300 amplitude correlated negatively with the severity of the thought disorder. The P300 amplitude in the patients with thought disorder was significantly smaller than in the patients without thought disorder. These results suggest that a reduction in P300 amplitude is associated with a fundamental impairment of information processing in schizophrenic patients.
Adult↗
Induction of terminal differentiation and apoptosis in human colonic carcinoma cells by brefeldin A, a drug affecting ganglioside biosynthesis.
An appreciable increase in G(M3) with a concomitant decrease in some neolacto-series gangliosides was observed during differentiation of human colonic carcinoma HCT 116 cells induced by a differentiating agent. When the cells were treated with brefeldin A (BFA), a striking increase in de novo biosynthesis of G(M3) and a decrease in biosynthesis of neolactoseries gangliosides were observed after 6 h. Clear morphological changes to differentiated epithelial cells and an arrest of cells in the G0/G1 phase of the cell cycle were observed after 1 day of treatment. Then the cells were led to apoptosis. This activity was not affected by forskolin, which antagonizes the effects of BFA on protein transport and the Golgi apparatus. These results suggest that the differentiation-inducing activity of BFA might be due to its modulatory effect on ganglioside biosynthesis, and that a specific change in ganglioside pattern is an essential prerequisite for induction of differentiation, providing a novel target for differentiation therapy of cancer.
Apoptosis↗
The parathyroid glands of two species of dolphin--Risso's dolphin, Grampus griseus, and bottlenose dolphin, Tursiops truncatus.
Although there have been many reports regarding the structure of the parathyroid glands of various terrestrial mammals, little is known about the parathyroid glands of marine mammals including Cetacea. The morphology of the parathyroid glands of three Risso's dolphins, Grampus griseus (about 3 m in length and 300 kg in weight), and three bottlenose dolphins, Tursiops truncatus (about 3 m in length and 300 kg in weight), was examined macroscopically and microscopically. The dolphins examined in the present study had two or four parathyroid glands that varied in size and location on the thyroid gland. Each parathyroid gland was encapsulated by fibrous tissue on the dorsal surface of the thyroid gland, and was divided into several lobules by interlobular connective tissue which contained numerous capillaries. The parenchymal cells consisted of pale staining chief cells. Each cell was polygonal and about 15 microm in diameter, and had one round or oval nucleus. Oxyphil cells were not found. Considering their greater body size, the parathyroid glands were rather small. By electron microscopic observation, the parathyroid gland of the bottlenose dolphin had sparse granular endoplasmic reticulum, poorly developed Golgi complexes, and abundant secretory granules in the cytoplasm of the chief cells. These results support a possibility that the activity of the parathyroid gland is suppressed to adapt to a sea habitat.
Animals↗
P3a of event-related potential in chronic methamphetamine dependence.
To investigate the psychophysiological features of methamphetamine (MAP) dependence, we recorded auditory event-related potentials (ERPs) in 15 patients with MAP dependence and in 15 age-matched normal controls. ERPs were recorded during a standard oddball task and a read task similar to those employed by Squires et al. (Squires NK, Squires KC, Hillyard SA [1975] Two varieties of long-latency positive waves evoked by unpredictable auditory stimuli in man. Electroenceph Clin Neurophysiol 38:387-401). The patients with MAP dependence showed reduced P3a amplitude and area in the read task and delayed P3b latency with normal P3b amplitude and area in the oddball task. These results suggest that central noradrenergic dysregulation may persist after the remission of acute psychotic symptoms in MAP psychosis and that chronic MAP dependence would produce impairment of the frontal cortex.
Acoustic Stimulation↗
Ultrastructure of the parathyroid gland of the young golden hamster after short-term treatment with ethanol.
We studied the ultrastructure of the parathyroid gland of young golden hamsters after short-term treatment with ethanol (1.5 g/kg bw or 6.0 g/kg bw). We did not find any ultrastructural changes of the parathyroid gland after administration of 1.5 g/kg ethanol. In the hamsters, 3 hours after administration of 6.0 g/kg ethanol, the mean serum calcium concentration was significantly low as compared to that of the control animals. In the parathyroid gland 1 hour after administration of 6.0 g/kg ethanol, the Golgi complexes associated with a few prosecretory granules and the volume density occupied by the Golgi complexes decreased compared with that of the control animals. In the parathyroid glands 3 hours after administration of 6.0 g/kg ethanol, the Golgi complexes decreased as compared with those of the control animals, while the large vacuolar bodies increased. These findings suggest that the cellular activity of the parathyroid gland is suppressed after short-term treatment with ethanol. Intracellular lumen was found in the parathyroid chief cells 3 hours after administration of 6.0 g/kg ethanol, and the significance of this structure is discussed.
Animals↗
Effect of immobilization on the ultrastructure of the golden hamster parathyroid gland.
To investigate the morphological changes of the parathyroid gland of the immobilized hamsters, we studied the ultrastructure of the parathyroid gland of golden hamsters kept in special small cage (Ballman cage II). All hamsters of the control group were kept in one ordinary cage. Each hamster of the isolated group was kept in ordinary cage individually. Each hamster of the immobilized group was kept in Ballman cage II individually. All hamsters were kept for 5 days. On the first and fifth day of the experiment, bone mineral content (BMC) and bone mineral density (BMD) of whole body were measured by dual energy X-ray absorptiometry (DXA). In the control and isolated groups, BMD of the fifth day was significantly increased as compared to that of the first day. In the immobilized group BMC and body weight were significantly decreased. There was no significant difference among 3 groups concerning the mean serum calcium level. Volume density of the cell organelles and inclusions was estimated and compared among 3 groups. Volume density of the lysosomes and large vacuolar bodies of the isolated and immobilized groups was significantly higher than that of the control group. Much more lipid droplets were observed in the immobilized group than the control and isolated groups. No particular differences were observed as to the Golgi complex in the isolated and the immobilized groups compared to the control group. These findings suggest that the cellular activity of the parathyroid gland is suppressed with immobilization.
Absorptiometry, Photon↗
Event-related potentials during a selective attention task with short interstimulus intervals in patients with schizophrenia.
OBJECTIVE: To study selective attention in schizophrenia by examining event-related potentials during a dichotic listening task with short interstimulus intervals (ISIs). DESIGN: Prospective study. PARTICIPANTS: Twelve patients with schizophrenia in remission and 12 age-matched controls with no history of psychiatric or neurological illness. INTERVENTIONS: Participants were asked to push a button in response to target stimuli in either ear. OUTCOME MEASURES: Reaction time, correct response rate and results of electroencephalography recorded at 3 regions: mean segmental amplitudes between 0 and 200 ms and between 200 and 400 ms after stimuli and processing negativity (Nd), measured by the negative area during these periods. RESULTS: Distinct slow-positive potentials for unattended stimuli, which were elicited in a task with long ISIs in a previous report, did not emerge in either group in this study. Although the 2 groups did not differ significantly in terms of Nd area, in the controls the mean segmental amplitude for attended standard stimuli was significantly greater than that in the patients with schizophrenia. CONCLUSIONS: Impairment of selective attention in patients with schizophrenia is related to a lack of ability to focus attention on attended task-relevant stimuli during a selective attention task with short ISI.
Adult↗
[Reproducibility and wave analysis of multifocal electroretinography].
We studied the reproducibility of multifocal electroretinography by repeated measurements in normal subjects. We also analyzed the amplitude and implicit time of the waves. Nine healthy eyes including myopic cases (-4.1 D on average) of 9 normal males, aged 19 to 42 years, were the objects of study. We used a (Visual Evoked Response Imaging System III (VERIS III), by TOMEY Corp.) for multifocal electroretinography. Each eye was examined 4 times on different days. The stimulus elements consisted of 103 hexagons. The net recording time was 4 minutes. We used the coefficient of variation (standard deviation/average) of 4 measurements of response density as index of reproducibility. Poor fixation and blinking were important factors that affected the reproducibility. In all the 9 eyes, reproducibility of multifocal electroretinography, expressed as average of the coefficient of variation of all regions, was 22% on average. In 6 eyes with good fixation and without blinking, the reproducibility was 15% on average. In 6 eyes with good reproducibility, we analyzed three parameters of the focal response waves: all traces, quadrants and rings, as well as the amplitude and latency of the waves. These data served as controls. Our studies showed that the response density correlated closely with the amplitude and not with the latency in normal subjects.
Adult↗
A study of the arterial supply of the human acetabulum using a corrosion casting method.
This anatomical study concerns the arterial supply of the human acetabulum. The purpose is to contribute to prevention of postoperative necrosis of the acetabular bone fragment after rotational acetabular osteotomy (RAO). The arterial supply of the acetabulum was determined using a corrosion casting method. The acetabular branch of the obturator artery supplies the acetabulum through the acetabular notch. The pubic branches supply the pelvic surface of the acetabulum. Deep branches of the superior gluteal artery supply the superior region and the inferior gluteal artery supplies the postero-inferior region. From these results, we recognized that the important artery for achieving successful RAO is the acetabular branch of the obturator artery that supplies the acetabulum through the acetabular notch.
Acetabulum↗
Auditory event-related potentials in panic disorder.
To investigate the psychophysiological features of panic disorder (PD), we recorded auditory event-related potentials (ERPs) in 12 patients with PD meeting the DSM-IV criteria and in 12 age-matched normal controls. The ERPs were recorded during a standard two-tone discrimination task (oddball task). The probabilities of the rare target (1200 Hz) and frequent non-target tones (1000 Hz) were 15 and 85%, respectively. The subjects were required to press a button in response to the rare target tones. Scalp electroencephalograms were recorded from Fz, Cz, Pz, C3, and C4. The State-Trait Anxiety Inventory and Manifest Anxiety Scale scores were assessed for clinical evaluation. Analysis of variance revealed that the N1 and N2 amplitudes for target tones and the N1 amplitude for non-target tones were significantly larger in the PD patients than those in the controls. The two groups did not differ significantly in P3 latency and amplitude. The larger N1 and N2 amplitudes in the PD patients are suggestive of alteration of early information processing in PD.
Adult↗