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Biomedical subjects

R Suzuki

Publications and source records attributed to R Suzuki.

At least 739 records · Page 41Linked to original sources
PubMed1981

Analysis of entrainment of circadian oscillators by skeleton photoperiods using phase transition curves.

A skeleton photoperiod consists of two short pulses which are applied on the circadian oscillator at times corresponding to the beginning and to the end of a continuous light stimulus. To study several problems in entrainment of circadian rhythms by skeleton photoperiods, we develop a simple diagrammatic solution of the steady state entrainment making use of phase transition curves which are directly gotten from phase response curves. The graphical method is simple and systematic to study entrainment by light cycles with various day lengths. As the method is also intuitive, we can easily examine three problems. (1) In Drosophila the phase relation (psi) between rhythm and light cycle is a continuous function of day length of skeleton photoperiods up to about 12 h, but a marked discontinuity (psi-jump) sets in between 13 and 14 h. By the diagrammatic method we find that psi-jump is mathematically a bifurcation phenomenon. (2) The action of photoperiods up to about 12 h is fully simulated by two 15-min skeleton pulses. Do 3-min skeleton pulses imitate the complete photoperiods? We find that pulse width is arbitrary to some extent. (3) Why skeleton photoperiods up to about 12 h are good models of complete photoperiods? The reason is the small amplitude and the nearly symmetrical form of phase response curves in the subjective day.

Animals↗
PubMed1981

The effectiveness of in-patient Morita therapy.

This study reports a followup survey of all 1287 Morita therapy patients treated over a 12 year period at Suzuki Clinic in Tokyo. Seventy one percent of all questionnaires sent out were completed and returned. Self evaluations by former patients indicated that slightly more than four fifths were improved to the degree that a relatively normal life was possible (regardless of presence of absence of symptoms). Improvements appeared to continue after discharge (i.e., it appeared to take time to incorporate the Moritist teachings into daily habit patterns) and to occur more rapidly for hypochondriasis and anxiety neurosis than for obsessive neurosis.

Follow-Up Studies↗
PubMed1981

Factors in the reproducibility of the gravimetric method for evaluation of edematous changes in the brain.

In the gravimetric method for estimation of water content in brain tissue, four factors that may affect specific gravity (SG) measurements are described and evaluated. These factors are: (1) the purity of kerosene (K) and monobromobenzene (MBB), (2) duration of interaction of MBB with tissue and/or standard solutions, (3) the size of tissue samples, and (4) the temperature. A water-soluble contaminant in K, which can be effectively extracted by water treatment, may significantly decrease SG values. Conversely, in MBB, the SG of tissue samples tends to increase in proportion with time. The SG of the tissue samples appears to be influenced by their size, the smaller pieces registering higher SG values. Also, the temperature of the column affects the SG, with higher temperatures resulting in higher SG values; a difference of 5 degrees C produces a significant difference in SG (p less than 0.05). A standardized procedure providing highly reproducible SG values is presented in which the size of the tissue samples, the recording time, and the temperature of the column consisting of water-treated K and MBB are kept strictly constant.

Animals↗
PubMed1981

Radiographic and radionuclide imaging in multiple myeloma: the role of gallium scintigraphy: concise communication.

Eighteen patients with multiple myeloma were studied using radiographs of the skeletal system, technetium phosphate bone scans, and gallium-67 scintigraphy. A total of 94 sites were used as the basis for comparison in these 18 patients. Radiographic sensitivity on a patient basis was 94%, and was 82% on a site basis. Bone scans were positive in 78% of patients and in 46% of sites. Gallium scans were positive in 56% of patients and 40% of sites. In five of the 18 patients, gallium scans showed activity in abnormal sites with a greater lesion-to-nonlesion ratio than did the bone scan. In this subgroup of patients, the disease was fulminant, and all died within 3 mo of their study. The finding of high gallium uptake in osseous sites that are normal or only slightly abnormal on bone scan has served to identify a subgroup of patients with rapidly progressive disease who may benefit from alternative treatment modalities such as radiation therapy.

Bone Neoplasms↗
PubMed1980

Mass spectrometric technique for the determination of N-phosphonoacetyl-L-aspartic acid in serum.

N-Phosphonoacetyl-L-aspartic acid (PALA), a potent inhibitor of aspartic acid transcarbamylase, is now undergoing Phase I clinical trials. Initial experiments revealed that PALA is not metabolized to phosphonoacetic acid (PAA) in humans. Thus PALA may be quantified in serum after in vitro conversion to PAA. Serum is deproteinized with perchloric acid, lipid extracted with methylene chloride, hydrolyzed with 8 N hydrochloric acid at 100 degrees for 3 h, and evaporated to dryness with nitrogen. The residue is silylated, and PAA is quantified by monitoring the (M + 1)+ ions of the protonated molecular ions of trimethylsilyl derivatives of PAA and phosphonopropionic acid (internal standard) obtained in chemical ionization with methane. Limit of detection is 0.5 microM (150 ng/ml) PALA using 1 ml serum. PALA was given by continuous infusion to cancer patients at various doses. Maximum levels of PALA (50-500 microM range) were obtained at the end of infusion, followed in most cases by biexponential decay. Persistent residual PALA levels (5 microM for 48 h after infusion) correlated with increased toxicity.

Antineoplastic Agents↗
PubMed1980

Two coupled oscillators as a model for the coordinated finger tapping by both hands.

Recently, it was found that rhythmic movements (e.g. locomotion, swimmeret beating) are controlled by mutually coupled endogeneous neural oscillators (Kennedy and Davis, 1977; Pearson and Iles, 1973; Stein, 1974; Shik and Orlovsky, 1976; Grillner and Zangger, 1979). Meanwhile, it has been found out that the phase resetting experiment is useful to investigate the interaction of neural oscillators (Perkel et al., 1963; Stein, 1974). In the preceding paper (Yamanishi et al., 1979), we studied the functional interaction between the neural oscillatory which is assumed to control finger tapping and the neural networks which control some tasks. The tasks were imposed on the subject as the perturbation of the phase resetting experiment. In this paper, we investigate the control mechanism of the coordinated finger tapping by both hands. First, the subjects were instructed to coordinate the finger tapping by both hands so as to keep the phase difference between two hands constant. The performance was evaluated by a systematic error and a standard deviation of phase differences. Second, we propose two coupled neural oscillators as a model for the coordinated finger tapping. Dynamical behavior of the model system is analyzed by using phase transition curves which were measured on one hand finger tapping in the preivous experiment (Yamanishi et al., 1979). Prediction by the model is in good agreement with the results of the experiments. Therefore, it is suggested that the neural mechanism which controls the coordinated finger tapping may be composed of a coupled system of two neural oscillators each of which controls the right and the left finger tapping respectively.

Fingers↗
PubMed1980

Sister-chromatid exchanges and chromosomal aberrations in cultured Chinese hamster cells treated with pesticides positive in microbial reversion assays.

The induction of sister-chromatid exchanges (SCEs), chromosomal aberrations and polyploids was investigated in cultured Chinese hamster cells treated with pesticides or a related compound positive in microbial reversion assays. The chemicals tested were captan, captafol, 1,2-dibromoethane (EDB), 1,2-dibromo-3-chloropropane (DBCP), 5-nitro-1-naphrhonitrile (NNN), p-dimethylaminobenzenediazo sodium sulfonate (DAPA), 2-hydrazinoethanol (HEH), vamidothion, dichlorovos (DDVP), N-nitroso-ethylenethiourea (N-nitroso-ETU), and 2,4-dinitrophenyl thiocyanate (NBT). A significant and dose-dependent increase in the frequency of SCEs and chromosomal aberrations was observed in the cell cultures treated with captan, captafol, EDB, DBCP, HEH, DDVP, vamidothion, DAPA or N-nitroso-ETU or NBT produced a significant increase in the frequency of polyploid cells, whereas the other agents did not. When compared with results from microbial reversion assays, a close correlation was observed between the ability to induce SCEs or chromosomal aberrations and the mutagenic potency in bacteria (r:0.71-0.84).

Aneuploidy↗
PubMed1980

Quantification of arabinitol in serum by selected ion monitoring as a diagnostic technique in invasive candidiasis.

D-Arabinitol was identified by mass spectrometry as a metabolite of Candida albicans and Candida tropicalis. For quantification, serum was deproteinized with acetone, the supernatant was evaporated to dryness, the silyl derivative was formed, and a portion was injected into a combined gas chromatograph-mass spectrometer system. Erythritol or 2-deoxy-galactitol was the internal standard. The protonated molecular ions, obtained in chemical ionization with isobutane, were monitored. For 39 normal subjects the mean endogenous arabinitol concentration was 0.52 microgram/ml (standard deviation, +/- 0.34). An increment of 0.2 microgram of arabinitol per ml could be quantified. Of 11 cases with diagnosed invasive candidiasis, 9 had arabinitol levels > 1.2 microgram/ml (8 microM) in the range of 1.2 to 25.0 micrograms/ml; the remaining 2 cases had levels in the normal range. Six cases of diagnosed colonized candidiasis showed normal arabinitol levels.

Adolescent↗