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Biomedical subjects

K Nishihara

Publications and source records attributed to K Nishihara.

At least 163 records · Page 9Linked to original sources
PubMed1985

Relationship between sleep efficiency and urinary excretion of catecholamines in bed-rested humans.

The relationship between urinary excretion of catecholamines during sleep and sleep disturbance was examined in four healthy subjects who were confined to bed for approximately 1 week under an entrained condition. Polysomnographic recordings were made throughout the period of continuous bed rest. Free epinephrine and norepinephrine excretion were measured. Sleep efficiency, i.e., percentage of total sleep time over an allotted sleep period, was an indicator of sleep disturbance. All subjects showed a negative correlation between sleep efficiency and epinephrine excretion (average correlation coefficient -0.79, p less than 0.004). Norepinephrine excretion correlated negatively with sleep efficiency in only one subject, and the group average correlation coefficient of -0.28 was not significant. Circadian variations were observed in sleep efficiency and catecholamine excretion. Although epinephrine excretion was influenced by psychophysiological stress arising from the experimental conditions of forced bed rest, the correlation between sleep efficiency and epinephrine excretion remained stable and negative. The urinary excretion of epinephrine could be an effective indicator of sleep disturbance.

Adult↗
PubMed1985

[Cervical dural ectasia in von Recklinghausen's disease].

A case of cervical dural ectasia in von Recklinghausen's disease is reported. A 36-year-old female was admitted to our hospital with complaints of hypesthesia in the extremities and gait disturbance. Plain cervical x-ray films showed dilated interpediculate distance and increased A-P diameter of the cervical spinal canal. Myelography showed abnormally dilated subarachnoid space at C4-C7 level. Metrizamide CT scan also revealed abnormally dilated subarachnoid space, which was at the ventral site of the spinal cord. No tumors, arachnoid cysts, syringomyelia were noticed. From the above-mentioned radiological findings, dural ectasia in von Recklinghausen's disease was suggested. In the discussion, it was emphasized to consider dural ectasia in the differential diagnosis of the dilated spinal canal.

Adult↗
PubMed1985

[Synchronized hemifacial spasm induced by sound stimulation].

A 42-year-old woman whose hemifacial spasm develops not only involuntarily but also synchronously to the sound stimulation to the left ear is presented. She had about 10 years history of left hemifacial spasm which occurred only involuntarily, and she was treated successfully by microvascular decompression method on June 1982. She had been uneventful and free from facial spasm until around January 1983, about 7 months after the first surgery, when her hemifacial spasm recurred and interestingly enough, this spasm started to occur not only involuntary but also synchronously to stimulation of the sound. On her electromyography (EMG) of the face, high amplitude discharge were noted sporadically during her facial muscle twitching, but more constant and regular high amplitude discharge on EMG were also evoked invariably and synchronously with the sound stimulation which was induced by 90 dB click sound and once this sound stimulation discontinued her facial muscle twitching ceased and abnormal discharge of EMG which appeared with sound stimulation disappeared instantly. On March 18, 1983, her left posterior fossa was explored and another angled artery was found compressing the facial nerve just at the root entry zone, more proximally than the previous site where the nerve was found compressed and decompressed at the first surgery. After complete replacement of this offending artery from the nerve, her facial spasm disappeared completely and was never evoked by the sound stimulation. Her postoperative EMG revealed no abnormal discharges at all after the sound stimulation by click sound in the ear.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1984

Hemangioma calcificans with circumscribed brain atrophy.

A case of hemangioma calcificans is presented. On CT scan, the tumor shows no mass effect but is accompanied by circumscribed low density which is deemed to indicate brain atrophy and an enlarged subarachnoid space. A case of this tumor surrounded by peritumoral brain atrophy has not been reported before.

Adult↗
PubMed1984

Effects of l-carnitine on action potential of canine papillary muscle during hypoxic perfusion.

Under hypoxic (95% N2 + 5% CO2) perfusion, electrophysiological effects of L-carnitine on canine papillary muscles were studied using standard microelectrode techniques. During hypoxic perfusion for 60 min, resting membrane potential (RMP), action potential amplitude (APA) and maximum upstroke velocity of phase 0 were decreased, and action potential duration (APD) and effective refractory period (ERP) were shortened. Application of L-carnitine 25 mM under hypoxic perfusion increased RMP and APA and prolonged APD and ERP significantly. As effects of L-carnitine during hypoxic perfusion might be that of hypertonicity, effects of sucrose of the same tonicity as L-carnitine were studied under hypoxia. Sucrose did not cause significant changes on various parameters of action potential compared with hypoxic perfusion. It was suggested that the increase in RMP, and the prolongation of APD and ERP might be caused by an increase in intracellular ATP content. The findings in this study could be an explanation of possible antiarrhythmic effects of L-carnitine.

Action Potentials↗
PubMed1984

Determination of pemoline in plasma, plasma water, mixed saliva, and urine by high-performance liquid chromatography.

A new determination method of pemoline in plasma, plasma water, mixed saliva, and urine using high-performance liquid chromatography was developed. The detection limit of pemoline using 0.2 ml of the sample was 0.02 microgram/ml in plasma, plasma water, saliva, and urine. The recoveries of pemoline added to plasma, saliva, and urine (each 6 micrograms/ml) were more than 98%. The coefficients of variation of within-run and between-run precisions for 5 concentrations of pemoline in plasma were less than 5 and 6%, respectively. The elimination half-lives of pemoline obtained from the plasma concentration-time curves after a single oral administration of pemoline in two subjects were 6.7 and 10.3 h. Mean values of the ratio between saliva and plasma total concentration in two subjects were 0.55 and 0.64, and mean values of plasma protein binding percent were 35.7 and 25.2%, respectively. The saliva concentrations were in proportion to the plasma unbound pemoline concentrations at simultaneous samplings, and the ratios between saliva and plasma unbound concentration were about 0.9 in two subjects. Usefulness of saliva in the estimation of plasma protein-unbound pemoline concentration was noted.

Adult↗
PubMed1984

Primary malignant lymphoma of the breast. With a review of 73 cases among Japanese subjects.

We report a case of a 71-year-old female with primary malignant lymphoma of the breast. The patient noticed a lump in the right breast approximately six years prior to consultation to the Surgical Department because of a rapid growth of the lump, and had no other tumors noticed throughout the body during that period. Histology proved the case to be a "reticulum cell sarcoma" (large cell type) producing IgM in the tumor cells, instead of a breast carcinoma as clinically diagnosed. At the same time, a total of 73 cases of mammary malignant lymphoma among Japanese subjects were reviewed. The criteria for primary or secondary malignant lymphoma of the breast, and histological diagnosis and pathogenesis of the primary breast malignant lymphoma were discussed.

Aged↗
PubMed1984

Effects of L-carnitine on exercise tolerance in patients with stable angina pectoris.

The effects of L-carnitine (900 mg, p.o. daily) on exercise performance were studied in 12 patients with stable effort angina using a multistage treadmill exercise test. Exercise tests were performed at the end of the placebo period and after 4 and 12 weeks of carnitine therapy. While 12 patients experienced angina during treadmill tests in the placebo period, 2 patients were free of angina after treatment with carnitine. The mean exercise time was 11.4 +/- 0.7 min (mean +/- SE) in the placebo period. This increased significantly to 12.2 +/- 0.5 min (p less than 0.05) after 4 weeks and 12.8 +/- 0.5 min (p less than 0.01) after 12 weeks of treatment with carnitine. The time required for 1 mm ST depression to occur was 6.4 +/- 0.9 min in the placebo period. This increased significantly to 7.6 +/- 0.9 min (p less than 0.01) after 4 weeks and 8.8 +/- 1.0 min after 12 weeks of treatment with carnitine. There was significantly less ST segment depression during the same exercise load after 12 weeks of treatment as compared with that in the placebo period (p less than 0.05). The heart rate and the pressure rate product at the same work load showed no significant difference among the 3 testing periods. The results of this study suggest that L-carnitine may improve exercise tolerance in patients with effort angina.

Adult↗
PubMed1983

Sleep apnea and nocturnal myoclonus in elderly persons in Vilcabamba, Ecuador.

Four men (M age 90.5 years) and four women (M age 91.2 years) in Vilcabamba, Ecuador (a community noted for people with extreme longevity) volunteered for sleep recordings using four-channel Medilog portable cassette recorder. Of the eight physically healthy persons recorded, only one man displayed sleep apnea syndrome. No nocturnal myoclonus was observed. Low incidence of sleep apnea of elderly persons in Vilcabamba may be due to a low barometric pressure and/or lack of drug abuse.

Aged↗
PubMed1983

Bioavailability of phenytoin on single and multiple oral doses of two dosage forms in normal subjects.

The extent and rate of absorption of phenytoin (PHT) from tablet and powder were studied in four healthy adult volunteers. It was demonstrated by urinary and fecal excretion that the almost all quantity of PHT in tablet was absorbed through the gastrointestinal tract, and the observed values of the estimated free concentration (Cest.f) estimated from mixed saliva concentration of PHT in the multiple dose were in fair agreement with the calculated values of that by using computer simulation in case of tablet. On the contrary, the variations were observed in Cest.f using therapeutic dose of PHT powder. The values of Cest.f at steady-state in tablet administration were higher than those in powder administration. The absorption ratio of PHT powder was low and variable, and decreased upon increase of dose. The ratio calculated from the Cest.f values of both dosage forms at steady-state were in good correspondence to the observed values of PHT excreted in feces.

Adult↗
PubMed1983

Comparison of bioavailability for phenytoin products prepared by wet granulation in normal subjects and epileptic patients.

A 20% phenytoin (PHT) plain mixture with excipients (20%PM) and three PHT products prepared by wet granulation, which are 20% fine granule (20%FG), 99% air-dried fine granule (99%FG-A) and 99% freeze-dried fine granule (99%FG-F), were prepared. The extents of PHT absorption from these products and the Aleviatin Fine Granules (97%FG) prepared with microcrystalline PHT powder were compared with those from commercially available PHT powder (Aleviatin) and tablet (Hydantol Tablet 25 mg), which are of the Pharmacopoeia of Japan grade, in healthy adult volunteers. In single dose study, the extents of PHT absorption from the powder, 20%PM, 20FG, 99%FG-A, 99%FG-F, 97%FG and tablet were 89.7, 92.2, 99.0, 96.7, 99.1, 99.1 and 99.3%, respectively. The property of almost complete absorption of PHT from the product was shown in the 20%FG, 99%FG-F and 97%FG similar to the tablet. In multiple dose study, the minimum and the average estimated free concentrations of PHT at steady-state for 99%FG-F and 97%FG were nearly equal to those for the tablet, and were higher than those for the powder. In epileptic patients, the plasma PHT concentrations were increased when dosage form was changed from the powder to 99%FG-F. However, the plasma PHT concentrations were scarcely altered when dosage form was changed from the tablet to 99%FG-F. The change in dosage forms from the tablet to 99%FG-F and 97%FG or opposite direction can be done without causing toxicity in epileptic patients, so long as these products are used at the same amounts as PHT.

Adolescent↗
PubMed1983

Effects of L-carnitine on ventricular arrhythmias after coronary reperfusion.

Effects of L-carnitine on ventricular arrhythmias and myocardial metabolism in a reperfused ischemic myocardium were studied in 35 anesthetized mongrel dogs. The left anterior descending coronary artery was ligated for 40 min and then reperfused for 15 min. L-carnitine (100 mg/kg) was administered intravenously 5 min before the coronary ligation and infused continuously at a rate of 20 mg/kg/min from 5 min before the reperfusion to the end of the experiment. Electrocardiograms were recorded continuously throughout the experiment. Transmural myocardial samples were obtained from both the ischemic and the nonischemic areas after 15 min of reperfusion and used for the determination of ATP, free carnitine, long chain acyl carnitine and long chain acyl CoA. L-carnitine significantly reduced the incidence rate of ventricular fibrillation after reperfusion (from 29% in the controls to 5%, p less than 0.05). ATP in the ischemic myocardium in the L-carnitine group was significantly higher than that in the control group (p less than 0.05). Free carnitine in the control group significantly decreased in the ischemic area as compared with the nonischemic area (p less than 0.01). In L-carnitine group, on the other hand, no difference was observed between them. Long chain acyl CoA in the control group significantly increased in the ischemic area as compared with the non-ischemic area (p less than 0.01). In L-carnitine group, on the other hand, no difference was observed between them. Thus, the accumulation of long chain acyl CoA in the ischemic myocardium was reduced by the L-carnitine treatment. These data suggest that L-carnitine has protective effects on ventricular arrhythmias and on metabolic changes after coronary artery reperfusion following coronary artery occlusion.

Animals↗