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H Toda

Publications and source records attributed to H Toda.

At least 19 recordsLinked to original sources
PubMed2005

High-speed gas sensor for chemosensory event-related potentials or magnetic fields.

The observation of odor and air exchange with high temporal accuracy is necessary to obtain strict chemosensory event-related potentials (CSERPs) or magnetic fields, as proposed by Evans et al. [Evans W, Kobal G, Lorig T, Prah J. Suggestions for collection and reporting of chemosensory (olfactory) event-related potentials. Chem Senses, 1993; 18: 751- 6]. No suitable method for real time observation of gas stimuli, however, has been available until now. We have developed a technique to measure accurately gas molecule concentrations with a high temporal resolution. We determined that attenuation of sound amplitude varies in a manner dependent on the average molecular weight through which the sound wave passes. Based on this principle, we have designed a high-speed gas concentration sensor utilizing ultrasound. We investigated the practical potential of this sensor using a chemosensory stimulator (olfactometer); we succeeded in observing rapid gas exchange between air and nitrogen with a 2 kHz sampling rate. The signal/noise ratio of the stimulus was greater than 42 dB. In a 20 min experiment we determined that, for this olfactometer, the gas onset latency was 79 ms and the rise time was 16 ms. No significant artifact to magnetic fields was observed, even when the sensor was situated near a whole head magnetoencephalography (MEG) system. These results indicate that this sensor could be used for the observation of odor and air exchange, as well as, for real time monitoring of odor stimuli during actual experiments with a participant.

Algorithms↗
PubMed2003

The comparative effects of propofol versus thiopentone on left ventricular function during electroconvulsive therapy.

The purpose of this study was to compare the effect of propofol versus thiopentone on haemodynamics during electroconvulsive therapy (ECT), as estimated by echocardiography. Twenty-eight ASA 1 or 2 patients scheduled for ECT were randomly divided into two groups, to receive propofol 1 mg/kg (propofol group, n = 14) or thiopentone 2 mg/kg (thiopentone group, n = 14). Bilateral ECT was performed after the administration of propofol or thiopentone, succinylcholine and following assisted mask ventilation with 100% oxygen. Cardiac function was examined by transthoracic echocardiography, prior to induction of anaesthesia and throughout ECT until ten minutes after the seizure. In the propofol group, increased end-systolic area (ESA) and decreased fractional area change (FAC) were observed at one minute after the electrical shock compared with the awake condition. In the thiopentone group, increased ESA and decreased FAC were observed from one to three minutes after the electrical shock compared with the awake condition. There was no statistically significant change in afterload in the propofol group during the study. In contrast, increased afterload was observed from one to three minutes after the electrical shock in the thiopentone group (awake condition, 26 +/- 7 mmHg/cm2 [mean +/- SD]; one minute after ECT, 42 +/- 7*; two minutes after ECT, 44 +/- 6*; three minutes after ECT; 40 +/- 5*, respectively) (*P < 0.05). We concluded that a lesser haemodynamic change occurs after propofol anaesthesia (1 mg/kg) compared with thiopentone anaesthesia (2 mg/kg) during ECT.

Adult↗
PubMed2002

Radiation-induced cerebral aneurysm successfully treated with endovascular coil embolization.

In a 30-year-old male, multiple cerebral aneurysms developed 19 years after receiving 60 Gy of irradiation for craniophariginoma. Angiogram revealed right IC-PC and upper basilar trunk aneurysms in addition to atherosclerotic change. The right IC-PC aneurysm was wrapped and the basilar trunk aneurysm located between the origins of SCA and AICA was treated by endovascular coil embolization. The packing of the aneurysm was complete, but stenosis of the basilar artery appeared. The patient was discharged uneventfully and follow-up angiogram 6 months later demonstrated that the aneurysm had disappeared and the patency of the basilary artery had been preserved. Radiation-induced intracranial vasculopathy is a well-recognized phenomenon, but aneurysm formation is less common than arterial occlusive lesion. However, the mortality rate after bleeding is so high that immediate diagnosis and treatment by direct surgery or coil embolization are necessary.

Adult↗
PubMed2002

Use of nitrogen stable isotope ratio of periphyton for monitoring nitrogen sources in a river system.

In order to confirm the usefulness of the N stable isotope ratio of periphyton (mainly composed of attached algae) as an indicator for monitoring the N sources in river watersheds, we measured the isotope ratio of periphyton along the Chikuma River. In the river, both the concentrations of dissolved total nitrogen (DTN) and the delta15N values of periphyton increased downstream. Specific nitrogen loading rates (SNLR) calculated from administrative data also showed an increase downstream from 7 to 11 kg N ha(-1) yr(-1), with the increasing contribution by sewage and livestock waste from 6 to 40% to total N loading. There are significant positive relationships between the DTN concentration and the SNLR (r2=0.54, P<0.05), and the delta15N values of periphyton and the SNLR (r2=0.78, P<0.05). The increase in DTN concentration reflected the increase in input of N loading. The increase in delta15N of periphyton might reflect the increase in relative contribution by sewage and livestock waste down the river, especially the increase in sewage. The present study indicates the usefulness of the N stable isotope ratio of periphyton as an indicator for monitoring N sources in a river system.

Animals↗
PubMed2001

Grafting neural stem cells improved the impaired spatial recognition in ischemic rats.

To determine the possible therapeutic potential of neural stem cells (NSCs) introduced into the damaged central nervous system, we grafted adult hippocampus-derived NSCs into the hippocampus of rats with transient global ischemia. Transient four-vessel occlusion yielded 90-95% losses of pyramidal neurons in the hippocampal CA1 region. In this region, 1-3% of the grafted cells survived; and 3-9% of them expressed NeuN, a neuronal marker. Rats with more than 120 NeuN-positive cells showed partial improvement of impaired spatial learning in a water maze test. These results suggest that NSCs grafted in the ischemic brain are able to differentiate into neurons and to improve spatial recognition.

Animals↗
PubMed2001

Regional comparison of nitrogen export to Japanese forest streams.

Nitrogen (N) emissions in Asian countries are predicted to increase over the next several decades. An understanding of the mechanisms that control temporal and spatial fluctuation of N export to forest streams is important not only to quantify critical loads of N, N saturation status, and soil acidification N dynamics and budgets in Japanese forested watersheds is not clear due to the lack of regional comparative studies on stream N chemistry. To address the lack of comparative studies, we measured inorganic N (nitrate and ammonium) concentrations from June 2000 to May 2001 in streams in 18 experimental forests located throughout the Japanese archipelago and belonging to the Japanese Union of University Forests. N concentrations in stream water during base flow and high flow periods were monitored, and N mineralization potential in soil was measured using batch incubation experiments. Higher nitrate concentrations in stream water were present in central Japan, an area that receives high rates of atmospheric N deposition. In northern Japan, snowmelt resulted in increased nitrate concentrations in stream water. The potential net N mineralization rate was higher in surface soil than in subsurface soil, and the high potential for N mineralization in the surface soil partly contributed to the increase in nitrate concentration in stream water during a storm event. Regional differences in the atmospheric N deposition and seasonality of precipitation and high discharge are principal controls on the concentrations and variations of nitrates in stream water in forested watersheds of Japan.

Ammonia↗
PubMed2001

Input-output budget of nitrogen and the effect of experimentally changed deposition in the forest ecosystems in central Japan.

To evaluate the current nitrogen (N) status in Japanese forests, field measurements of rainfall, throughfall, litter layer percolation, and soil solution percolation were conducted in a red pine stand (Kannondai) and a deciduous stand (Yasato) located in central Japan. N input via throughfall was 31 and 14 kg ha(-1) year(-1) and output below rooting zone was 9.6 and 5.5 kg ha1 year(-1) in Kannondai and in Yasato, respectively. Two thirds of input N were retained in plant-soil systems. Manipulation of N input was carried out. Ionic constituents were removed from throughfall with ion exchange resin at removal sites and ammonium nitrate containing twice the N of the throughfall was applied at N addition sites periodically. SO4(2-) output below 20-cm soil layer changed depending on the input, while NO3- output was regulated mainly by the internal cycle and effect of manipulation was undetected. These Japanese stands were generally considered to have a larger capacity to assimilate N than NITREX sites in Europe. However, N output fluxes had large spatial variability and some sites in Kannondai showed high N leaching below rooting zone almost balanced with the input via throughfall.

Ammonia↗
PubMed2001

Relationships between the activities in vitro and in vivo of various kinds of ribozyme and their intracellular localization in mammalian cells.

Nineteen different functional RNAs were synthesized for an investigation of the actions of ribozymes, in vitro and in vivo, under the control of two different promoters, tRNA or U6, which localize transcripts either in the cytoplasm or in the nucleus. No relationships were found between the activities of these RNAs in cultured cells and the kinetic parameters of their respective chemical cleavage reactions in vitro, indicating that in no case was chemical cleavage the rate-limiting step in vivo. For example, a hepatitis delta virus (HDV) ribozyme, whose activity in vitro was almost 3 orders of magnitude lower than that of a hammerhead ribozyme, still exhibited similar activity in cells when an appropriate expression system was used. As expected, external guide sequences, the actions of which depend on nuclear RNase P, were more active in the nucleus. Analysis of data obtained with cultured cells clearly demonstrated that the cytoplasmic ribozymes were significantly more active than the nuclear ribozymes, suggesting that mature mRNAs in the cytoplasm might be more accessible to antisense molecules than are pre-mRNAs in the nucleus. Our findings should be useful for the future design of intracellularly active functional molecules.

Base Sequence↗
PubMed2001

Differential inhibitory mechanism of Fe2+ and Fe3+ on contraction of ileal longitudinal smooth muscle.

The mechanism of the inhibition of K(+)-induced contraction caused by ferrous (Fe(2+)) and ferric (Fe(3+)) ions were analysed in guinea-pig ileal longitudinal muscle and taenia coli. Fe(2+)increased the threshold for Ca(2+)-induced contraction in Ca(2+)-free, K(+)-depolarized taenia coli. However, Fe(3+)reduced the size of the maximal response to Ca(2+)without shifting the dose-response curves in taenia coli. Both 10 mM Fe(2+)and 2 mM Fe(3+)caused significant decreases in Ca uptake, as determined by the La method, during K(+)-induced ileal contraction. After treatment with 10 mM Fe(2+)in a state of cell membrane depolarization with K(+)for 30 min, the ileal K(+)-induced tonic contraction was completely restored by washing with medium containing EDTA, a chelator of divalent cations, and Fe(2+)remaining in muscle was almost eliminated by washing. In contrast, after treatment with 2 mM Fe(3+)in K(+)medium, K(+)-induced contraction was reversed only to a slight degree by washing with medium containing deferoxamine, a chelator of trivalent cations, and Fe(3+)in muscle largely remained despite the washing. These results suggest that Fe(2+)binds to the ileal surface membrane and reduces the contraction in response to K(+)mainly by inhibiting Ca(2+)influx. Fe(3+)may exert an inhibitory action on intracellular sites, in addition to the interference of Ca(2+)influx at the cell membrane.

Animals↗
PubMed2001

Prognostic significance of carcinoembryonic antigen levels in peritoneal washes in patients with gastric cancer.

BACKGROUND: Peritoneal metastasis is the most frequent cause of death in patients with gastric cancer. Detection of free cancer cells in the peritoneal cavity at the time of surgery, therefore, is considered to be of great value in predicting the peritoneal recurrence and accordingly in the prognosis in patients with gastric cancer. This study examined the clinical significance of intraoperative determination of carcinoembryonic antigen (CEA) levels in peritoneal washes (pCEA) in patients with gastric cancer. METHODS: CEA levels in peritoneal washes were correlated retrospectively with several clinicopathologic factors including clinical outcome in 56 patients with resectable gastric cancer. RESULTS: Among several clinicopathologic factors, the depth of tumor invasion significantly and independently correlated with pCEA levels as revealed by multivariate stepwise logistic regression analysis. A significant difference in overall survival rates was observed between pCEA-positive and pCEA-negative groups: 5-year survival rates were 95.7% in pCEA-negative and 20% in pCEA-positive patients (P <0.0001). Multivariate analysis indicated that pCEA level is a statistically significant independent prognostic factor for the survival of patients with gastric cancer, and is an important factor for predicting peritoneal recurrence. CONCLUSIONS: pCEA could be a potential predictor of a poor prognosis as well as peritoneal recurrence in patients with gastric cancer. We believe that this information could contribute to determining the optimal intraoperative and postoperative therapeutic plan including adjuvant chemotherapy of gastric cancer.

Adult↗
PubMed2001

The properties of convergence eye movements evoked from the rostral and caudal lateral suprasylvian cortex in the cat.

Convergence eye movements were evoked in the lateral suprasylvian cortex (LS cortex) in the cat. Three effective regions were found: the rostral and caudal parts of the postero-medial LS cortex (the PMLS) and the rostral part of the postero-lateral LS cortex (the PLLS). These three areas represent the central and paracentral visual fields in the published retinotopic map (Palmer et al., 1978). Convergence eye movements evoked from the caudal PMLS were divided into two groups based on their latencies; the short-latency components (SLC) and long-latency components (LLC). The SLC and the LLC had differences in their symmetry of right and left eye movements during vergence eye movement. The SLC had symmetric right and left eye components and the LLC had dominant contralateral eye components. In the rostral PMLS, latencies of evoked convergence eye movement were comparable to those of the caudal PMLS, but they did not divided into two groups. Convergence eye movements evoked from the PLLS had longer latencies than those from the PMLS and asymmetric right and left eye components. It is suggested that different subregions in the LS cortex contribute to the control of convergence eye movement, playing different roles.

Animals↗
PubMed2001

[Public music concerts in a psychiatric hospital: effects on public opinion and as therapy for patients].

We investigate the effects of music therapy concerts, which were held 60 times over a four year period, 1992 to 1996, in Geiyo Psychiatric Hospital, Kochi Prefecture and found that; 1) Musicians who performed at the concerts were not only from Kochi prefecture but also from other prefectures (10 times) and from four foreign countries (7 times). 2) Live concerts in a small hall had a positive influence on patients and drew the patient's attention and interest away from their hallucinations and delusions to the real world. Moreover, the concerts provided the patients with chances to acquire social graces such as being well-groomed. 3) Explanations by the musicians, interviews with the musicians and the seasonal choruses accompanied by the musicians were helpful to give the patients motives for recovering communication skills and to interact with society. 4) Inquiries to the patients about the concerts indicated discrepancies between the poor observed estimations during the concerts (83.3%) and the good subjective impressions expressed by the patients (82.0%), suggesting that the patients were not good at expressing their internal emotions through facial expressions or attitudes. 5) Many citizens including children came to the concerts and/or gave aid to the hospital because the concerts were open to the public and we suggest that this contributed to improving the general publics' image of psychiatric hospitals. Questionnaires revealed that 90% of people in a control group had a bad image of psychiatric hospitals in Japan, but only 32% of the members of the general public who attended our concerts had a bad image of psychiatric hospitals. In addition, the revolving ratio of the hospital beds rose from 0.4 to 1.2 over the four years, which also suggests a beneficial effect on the patients.

Hospitals, Psychiatric↗