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Biomedical subjects

S Usui

Publications and source records attributed to S Usui.

At least 127 records · Page 7Linked to original sources
PubMed1990

Chemical robot for enzymatic reactions and extraction processes of DNA in DNA sequence analysis.

A chemical robot capable of performing enzymatic reactions and extraction processes of DNA has been developed. The basic functions of this robot include handling of plastic tubes with caps, micropipetting, mixing, microcentrifuging and incubating. As a result, almost all of the pre-electrophoresis steps can be carried out. In addition, because these processes are automated, the working time of each process can be reduced. The reproducibility of the automated operation is equivalent to that of a skilled operator.

Base Sequence↗
PubMed1990

[Study of risk factors for postoperative pulmonary complications following esophageal cancer surgery--multivariate statistical analysis].

In 91 patients undergoing resection and reconstruction of the esophagus for esophageal cancer, risk factors for postoperative pulmonary complications were studied. In order to investigate these factors, multivariate statistical analysis was applied. The incidence of postoperative pulmonary complications was significantly higher in patients over 70 years of age who had poor renal function (PSP15' less than 25%) and had prolonged thoracotomy time (greater than 3 h) by Student's t test. In preoperative pulmonary functions, obstructive respiratory dysfunction (MMF, FEV1.0) correlated well with postoperative pulmonary complications. The analysis of each factor was, however, not enough to predict the risk of pulmonary complications following operation. Meanwhile, risk score (= 2.0 (age) + 1.0 (FVC) + 0.7 (MMF) + 1.5 (PSP15') + 1.8 (thoracotomy time) + 1.7 (postoperative RI] was obtained by multivariate statistical analysis. High incidence (greater than 80%) of pulmonary complications was observed in patients with risk score more than 5.0. It is suggested that using this risk score will be helpful for postoperative pulmonary care.

Esophageal Neoplasms↗
PubMed1989

Purification and properties of isopenicillin N epimerase from Streptomyces clavuligerus.

Isopenicillin N epimerase, which catalyzes conversion of isopenicillin N to penicillin N, has been purified to electrophoretic homogeneity from the cell-free extract of Streptomyces clavuligerus by a procedure involving ammonium sulfate fractionation and chromatographies with DE-52, DEAE Affi-gel blue, Sephadex G-200, calcium phosphate-cellulose, and Mono Q. The purified epimerase is monomeric with a molecular weight of 47,000 or 50,000 as estimated by SDS-polyacrylamide gel electrophoresis or gel filtration, respectively. The enzyme contains 1 mol of pyridoxal 5'-phosphate per mol of protein, and shows absorption maxima at 280 and 420 nm. The epimerase catalyzes the complete 'racemization' on both the L-alpha-aminoadipyl side-chain of isopenicillin N and the D-alpha-aminoadipyl side-chain of penicillin N, so that an approximately equimolar mixture of the two penicillins is produced. The mixture is not truly racemic, since these penicillins are diastereomers rather than optical isomers. The chemical modification of primary amino groups of the epimerase by fluorescamine results in a great loss of the enzyme activity. The activity of purified enzyme is partially stimulated by the addition of sulfhydryl compounds. The activity is strongly inhibited by sulfhydryl group modifiers such as p-chloromercuribenzoate and N-ethylmaleimide.

Amino Acid Isomerases↗
PubMed1989

Circadian behavioral rhythms during various light-intensity cycles in rats.

Sleep, ambulation and drinking were recorded on 5 kinds of light-intensity cycles fluctuating between 300 lux and 0 lux with a 24-hr period in rats. The waveforms of the cycles were rectangular wave (RA), sinusoidal wave (SO), triangular wave (TA), descending saw-tooth wave (ST-d) and ascending saw-tooth wave (ST-a). Each condition was maintained for 28 days. Thereafter, the rats were released into constant darkness (DD) for 20 days. The circadian behavioral rhythms clearly entrained to RA, SO, TA and ST-a, but not to ST-d. The waveforms of the behavioral rhythms varied depending on those of the fluctuating light-intensity cycles, and were quite different from those in RA and DD. Daily amounts of slow wave sleep and paradoxical sleep were hardly affected by the lighting conditions, while those of ambulation and drinking were decreased on the other light-intensity cycles than RA. These results present new aspects of entrainment and masking of circadian rhythm by light.

Animals↗
PubMed1989

Functional properties of monkey caudate neurons. I. Activities related to saccadic eye movements.

1. We recorded single cell activities in the caudate nucleus of the monkeys trained to perform a series of visuomotor tasks. In the first part of this paper, we summarize the types and locations of neurons in the monkey caudate nucleus. In the second part, we report the characteristics of neurons related to saccadic eye movements. 2. Neurons were classified into two types in terms of spontaneous discharge pattern. A majority of the neurons (2,287/2,559, 89%) had very low-frequency discharges (mostly less than 1 Hz). The rest (n = 272) showed irregular-tonic discharges (3-8 Hz) with broad spikes. 3. Of 2,559 neurons tested, 867 showed spike activity related to some aspects of the tasks; 502 neurons showed discharges in response to environmental changes outside, not in relation to, the tasks. None of the neurons responsive in or outside the tasks belonged to the irregular-tonic type. 4. The task-related activities were classified as: Saccade-related, Visual, Auditory, Cognitive, Fixation-related, and Reward-related. The activities detected outside the tasks were classified into: Visual, Auditory, Movement-related, Reward-related, and Other. Few neurons had both task-related and task-unrelated activities. 5. The locations of recorded neurons were determined using a coordinate system based on the anterior and posterior commissures. Task-related neurons were clustered longitudinally in the central part of the caudate. Neurons responsive outside the tasks were more widely distributed; specifically, auditory neurons were in the medial part, whereas movement-related neurons were in the lateral part. The irregular-tonic neurons were dispersed all over the caudate. 6. The monkey was trained to fixate on a spot of light on the screen and, when the spot moved, to follow it by making a saccade. A visually guided saccade occurred when the spot moved to another location without a time gap (saccade task). A memory-guided saccade occurred when the spot first disappeared and after a time gap reappeared at a fixed location (saccade with gap task). By delivering a cue stimulus while the monkey was fixating, a memory-guided saccade was elicited to a randomly chosen location (delayed saccade task).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Functional properties of monkey caudate neurons. II. Visual and auditory responses.

1. Visual responses of caudate neurons were studied in monkeys trained to fixate on a small spot of light. A visual stimulus (another spot of light) was presented in various contexts of behavior using different behavioral paradigms. Visual receptive fields were usually large and centered on the contralateral hemifield. Among 217 neurons with visual responses, 184 were further classified into subtypes. 2. Visual responses in 64 neurons were not modulated by changing the paradigms (unconditional visual responses). In the other neurons, visual responses were dependent on the behavioral contexts in which the stimulus was presented. Three types of behavioral modulation were found. 3. A saccade-enhanced visual response (n = 37) was the one that was enhanced if the monkey made a saccade to the stimulus on its appearance. The enhancement was spatially selective: the response was depressed if the saccade was directed away from the stimulus. 4. Memory-contingent visual responses (n = 36) were present preferentially when the monkey remembered the location of the stimulus and a few seconds later made a saccade to the remembered location. Responses were greater when the location of the stimulus was randomized between trials. 5. Expectation-contingent visual responses (n = 46) were present preferentially when the stimulus came on while the monkey was not fixating another spot, and the stimulus was related directly to a reward. Unlike the other types, its receptive field included both contralateral and ipsilateral hemifields without a particular preference. 6. A small number of neurons (n = 16) showed a visual response that easily habituated. 7. Latencies of visual responses were usually between 100 and 200 ms. The latencies of the memory-contingent, expectation-contingent, and habituated visual responses tended to be longer than the others and tended to be more variable between trials. 8. Among auditory responsive neurons only a small proportion were related to the tasks. The response was greater to a contralateral sound. It was enhanced if the monkey used the sound as the cue for the future target location. 9. The results suggest that sensory responses of caudate neurons could be used to guide a subsequent sequence of learned behaviors by confirming predicted environmental states, renewing memory, or establishing a motor set.

Animals↗
PubMed1989

Functional properties of monkey caudate neurons. III. Activities related to expectation of target and reward.

1. The present paper reports complex neural activities in the monkey caudate nucleus that precede and anticipate visual stimuli and reward in learned visuomotor paradigms. These activities were revealed typically in the delayed saccade task in which memory and anticipation were required. We classified these activities according to their relationships to the task. 2. Activity related to expectation of a cue (n = 46) preceded the presentation of a spot of light (target cue) that signified the future location of saccade target. When the target cue was delayed, the activity was prolonged accordingly. The same spot of light was preceded by no activity if it acted as a distracting stimulus. 3. The sustained activity (n = 80) was a tonic discharge starting after the target cue as if holding the spatial information. 4. The activity related to expectation of target (n = 109) preceded the appearance of the target whose location was cued previously. It started with or after a saccade to the cued target location and ended with the appearance of the target. The activity was greater when the target was expected to appear in the contralateral visual field. 5. The activity related to expectation of reward (n = 57) preceded a task-specific reward. It started with the appearance of the final target and ended with the reward. In most cases, the activity was nonselective for how the monkey obtained the reward, i.e., by visual fixation only, by a saccade, or by a hand movement. The activity was dependent partly on visual fixation. 6. A few neurons showed tonic activity selectively before lever release and are thus considered to be related to the preparation of hand movements. 7. The activity related to breaking fixation (n = 33) occurred phasically if the monkey broke fixation, aborting the trial. 8. Activity related to reward (n = 104) was a phasic discharge that occurred before or after a reward of water was delivered. The activity was not simply related to a specific movement involved in the reward-obtaining behavior (eye, hand, or mouth movement). 9. Fixation-related activity (n = 72) was tonic activity continuing as long as the monkey attentively fixated a spot of light. It was dependent on reward expectancy in most cases. 10. The present results, together with those in the preceding papers, indicate that the activities of individual caudate neurons--sensory, motor, or cognitive--are dependent on specific contexts of learned behavior.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

New mathematical modelling of blood lactate kinetics during ramp mode exercise in man.

The lactate (LA) kinetics of the whole body in exercise was described using the two-compartment model in consideration of the underlying physiological mechanism, and LA kinetics during the ramp mode exercise was analyzed. The estimated pattern of the glycolytic energy supply showed the progressive increase concurrently with the onset of ramp mode exercise and this pattern was just like a ramp phenomenon. Based on this result, it is proposed that blood LA kinetics during ramp exercise should be described mathematically as a continuous model, called "2nd-order model."

Exercise↗
PubMed1988

Sleep-promoting effect following intracerebroventricular injection of a phosphorylated analogue of delta sleep-inducing peptide (DSIP-P) in rats.

The effect of phosphorylated delta sleep-inducing peptide (DSIP-P) on sleep of rats was studied. DSIP-P (20 or 200 pmol/kg) was injected into the third cerebroventricle of male rats immediately before the onset of the dark period of a 12:12 h light-dark cycle. DSIP-P resulted in increases of slow-wave sleep (SWS) (17.3%, P less than 0.01) and paradoxical sleep (PS) (32.3%, P less than 0.05) during the subsequent dark period without shortening sleep latency in the dose of 200 pmol/kg. The SWS-promoting effect was carried over to the next light period. These changes returned to control levels on the second day. These results indicate that DSIP-P is a long-lasting sleep-promoting substance in rats.

Animals↗
PubMed1988

Comparison of objective methods for determining ventilatory threshold.

This study was undertaken to compare and re-examine the relation of lactate threshold (LT) and ventilatory threshold (VT), using six objective determination methods proposed previously. Twenty-one young male subjects performed a cycle exercise test in which the work rate was increased by 150 kg.m every 2 min up to his limit of volitional fatigue. Through each test, gas exchange parameter measurements were made every 1 min (every 30 s at nearly maximal level), and the venous blood samples were taken from a warmed ear lobe at each work rate for determining blood lactate concentration. LT and its variance were determined by the intersecting straight lines regression. LT ranged from 0.72 to 1.40 l/min in terms of VO2, and the mean value of S.D. for each LT was about 0.1 l/min. Each objective method for determining VT used in this study was based on the simple modelling of the criterion for visual detection of VT, that is the non-linear increase in VE or the systematic increase in VE/VO2. When the relationship between LT and VT was examined, VT by the objective methods based on determining minimum value of VE/VO2 showed relatively high consistency with LT. Of 16-20 individuals out of all 21 subjects, there were VT within LT +/- 0.2 in VO2. It is concluded that VE/VO2 is a more sensitive index for detecting VT than VE in the gas exchange parameters, and the objective VT determination method based on minimum value of VE/VO2 could facilitate estimation of LT within an error of +/- 0.2 l/min VO2 in most normal individuals.

Adult↗
PubMed1988

[Metrizamide encephalopathy in a child with hydrocephalus--effects of L-threo-DOPS on persistent disturbance of consciousness and L-dopa on extrapyramidal symptoms].

This report describes a case of metrizamide encephalopathy with persistent disturbance of consciousness and extrapyramidal symptoms. These two conditions have rarely been reported among the various adverse effects of metrizamide. An 11-year-old girl had been in almost good health until she was ten years old, at which time she received a ventriculo-peritoneal shunt operation, suffering from hydrocephalus of unknown etiology. At the age of eleven, she was admitted to our hospital due to hydrocephalus recurrence. She was examined by metrizamide shunt-gram (1200 mg iodide/4 ml). On the next day, she became drowsy. The CT scan disclosed the periventricular penetration of metrizamide into the medial part of the thalamus and the caudate nucleus. Thirteen days later, disturbance of consciousness continued, and extrapyramidal symptoms, that is, rigo-spasticity and postural tremor, were observed. Oral administration of L-threo-DOPS, the direct precursor of noradrenaline, was effective against the persistent disturbance of consciousness and L-DOPA was effective against the extrapyramidal symptoms. She soon recovered almost to normal and no neurological deficit remained. We thus conclude that the CT scan findings and effects of L-threo-DOPS and L-DOPA suggest that metrizamide encephalopathy in this case were respectively due to its periventricular penetration into the medial part of the thalamus and the caudate nucleus, and the resultant deficiency of the ascending noradrenergic reticular activating system and the nigrostriatal dopaminergic system.

Basal Ganglia Diseases↗
PubMed1988

[A family of spino-cerebellar degeneration with disturbance of ocular movement, choreoathetosis, amyotrophy and dementia--a consideration in clinical features].

Seven cases in a family of hereditary spino-cerebellar degeneration (SCD) similar to dentatorubro-pallido-Luysian atrophy (DRPLA) were reported. The clinical features of these cases were disturbance of ocular movement (limitation of ocular movement and slow eye movement (SEM], remarkable amyotrophy, choreoathetosis, dementia and sleep apnea. The brain CT's revealed marked atrophy in pons and cerebellum. Amyotrophy had been reported in the case of DRPLA, particular ataxo-choreoathetoid form (by Hirayama). Muscle biopsy was performed in these cases, which showed scattered small angulated fiber, severe atrophic fiber with pyknotic nuclear clump, fiber type grouping and small rounded fiber were mixed. These findings indicates neurogenic change of radiculoneuropathy type (by Tanabe). In many reported cases of DRPLA and SCD with amyotrophy, this type of muscle biopsy had not been recognized. In SCD with amyotrophy, a main lesion had existed on peripheral nerve. In this case, there was no definite clinical findings (sensory disturbance, delay of conduction nerve velocity, peripheral neuropathy in nerve biopsy). In recent years, several unclassified cases of SCD with amyotrophy had been reported, which had multi-system degeneration involving peripheral neuropathy. This case is similar to these cases, which is speculates multi-systemic lesions, not only DRPLA but also peripheral nerve involvement. On neuro-otological study, velocity of saccade was slow and persuit was reserved in proband case. In younger onset case, disturbance of saccade and pursuit was mild. In older progressive case, disturbance of saccade and pursuit was progressive and accompanied with severe limitation of ocular movement. Several autopsy cases of SEM had been reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Evaluation of the nutritional management of patients with liver cancer and cirrhosis].

Ninety-five patients with liver cancer and cirrhosis who had undergone hepatic lobectomy or partial hepatectomy were studied. According to nutritional protocol based on experimental results, a large quantity of fresh frozen plasma (FFP), and BCAA-enriched amino acids at 30 kcal/kg/d as an energy source were administered postoperatively for 7-10 days with strict restriction of sodium and total fluid volume. An elemental diet for liver dysfunction (ED-H) was given to 13 patients at more than 1,500 kcal/d via a naso-duodenal feeding tube for 7-14 days. Six patients were given 15 g/d of BCAA granules after discharge for as long as possible. Serum levels of TP, Alb, T.Bil and PT were kept moderately high in the IVH and ED-H group. Although BCAA/AAA molar ratio was kept high when IVH or ED-H was provided, it gradually fell if nutritional management was discontinued. This ratio was maintained within normal limits by oral administration of BCAA granules. According to the Child classification, 1,2,3 and 5-year cumulative survival rates were 80.9, 62.9, 44.1 and 25.5% for Child A, 70.0, 43.1, 43.1 and 0% for Child B, and 50.0, 25.0, 0 and 0% for Child C, respectively. These data indicate the importance of nutritional support for improvement of nutritional status and for obtaining a better prognosis. Oral BCAA supplementation should be useful for the performance of long-term nutritional management for cancer patients with liver cirrhosis.

Amino Acids, Branched-Chain↗
PubMed1987

Effect of sucrose and caffeine ingestion on performance of prolonged strenuous running.

To investigate the effect of sucrose or caffeine ingestion on the performance of prolonged running, five male distance runners attending senior high school (15.6 yrs) carried out running on a treadmill at an intensity corresponding to the individuals' 80% VO2 max until exhaustion. Before and 45 min after exercise, the subjects were given either a placebo (Con), sucrose (81 +/- 18 g) (Su), caffeine (384 +/- 13 mg) (Caf), or sucrose (72 +/- 22 g) plus caffeine (396 +/- 29 mg) (Su + Caf) solution. The duration of the exercise was significantly longer in Su, Caf, and Su + Caf than in Con. The duration in four of five subjects was longest in Su + Caf, although it was not significantly different from that in Su or Caf. Carbohydrate (CHO) utilization was highest in Su while fat utilization was highest in Caf. The energy supply from both sources was almost the same between Con and Su + Caf. The plasma glucose concentration was higher in Su than in Con. The plasma free fatty acid (FFA) level was higher in Caf than in Con. The plasma glucose and lactic acid concentrations were highest in Su + Caf while the plasma FFA level was the same as in Con. In conclusion, ingestion of sucrose, caffeine, or sucrose plus caffeine solution was equally effective in improving endurance during running carried out at an intensity of approximately 80% VO2 max.

Adolescent↗