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Biomedical subjects

Y Motohashi

Publications and source records attributed to Y Motohashi.

At least 73 records · Page 4Linked to original sources
PubMed1989

Circadian and seasonal variations of electrolytes in aging humans.

The circadian and seasonal variations of a set of routinely determined variables (chloride, sodium, potassium, calcium, inorganic phosphorus, magnesium, creatinine, urea and urate) were documented in young men (mean age +/- SD: 24.0 +/- 3.9 yr) and in healthy elderly men (75.3 +/- 6.6) and women (78.2 +/- 9.1). The same urinary variables, except magnesium, were studied in young men. The circadian variability of serum variables was between 2 and 11% except for serum inorganic phosphorus (12-22% according to the group). By contrast, urinary chloride, sodium and potassium revealed large peak-trough differences (55-75%) and the variability of urinary creatinine, urate and urea was also not negligible (20-30%). ANOVA validated seasonal variations for most of the plasma variables and for urinary calcium, phosphorus and uric acid. No age or sex difference in either 24 h means or amplitudes could be observed. These data are of interest for the concept of reference values, for the diagnosis of certain bone and renal disease as well as for chronooptimization in treatment of potential electrolytes deficiency states.

Aged↗
PubMed1988

Alteration of period and amplitude of circadian rhythms in shift workers. With special reference to temperature, right and left hand grip strength.

48 male shift workers in various industries volunteered to document circadian rhythms in sleeping and working, oral temperature, grip strength of both hands, peak expiratory flow and heart rate. All physiological variables were self-measured 4 to 5 times a day for 2 to 4 weeks. Individual time series were analyzed according to several statistical methods (power spectrum, cosinor, chi squares, ANOVA, correlation, etc.) in order to estimate rhythm parameters such as circadian period (tau) and amplitude (A), and to evaluate subgroup differences with regard to tolerance to shift work, age, duration of shift work, speed of rotation and type of industry. The present study confirms for oral temperature and extends to other variables (grip strength of both hands, heart rate) that intolerance to shift work is frequently associated with both internal desynchronization and small circadian amplitude. The internal desynchronization among several circadian rhythms supports the hypothesis that these latter are driven by several oscillators. Many differences were observed between circadian rhythms in right and left hand grip strength: circadian tau in oral temperature was correlated with that in the grip strength of the dominant hand but not with that of the other hand; changes in tau s of the non-dominant hand were age-related but did not correlate with temperature tau; only the circadian A of the non-dominant hand was associated with a desynchronization. Thus, circadian rhythms in oral temperature and dominant hand grip strength may be driven by the same oscillator while that of the non-dominant hand may be governed by a different one. Internal desynchronization between both hand grip rhythms as well as desynchronization of performance rhythms reported by others provide indirect evidence that circadian oscillator(s) may be located in the human cerebral cortex.

Adult↗
PubMed1988

Circadian rhythm in total pulmonary resistance of asthmatic children. Effects of a beta-agonist agent.

Six children (boys and girls, 8 to 13 years old) with allergic asthma (AA) had their total pulmonary resistance (R1) measured at four fixed times (0730, 1130, 1630 and 2230 hr), before and again 10 min after a 2 mg orciprenaline (beta-agonist) aerosol inhalation. R1 was measured by means of the esophageal balloon technique. Subjects were socially synchronized in May with a diurnal activity from 0700 to 2100 and a nocturnal rest. Patients had had no asthma attacks and had received no medication for 8-15 days. Time series were analyzed according to conventional (t-tested mean time point differences) ANOVA, and cosinor methods. The 24 hr adjusted means (cm H2O.l/s +/- SEM) were 5.7 +- 0.4 in seven previously documented healthy children. 7.4 +/- 1.2 in AA before orciprenaline, and 4.9 +/- 0.2 in healthy children, 5.2 +/- 0.8 in AA after beta-agonist inhalation. Circadian rhythms were detected in both groups before but not after treatment. The treatment had its maximal effect on R1 around 0730 (when bronchial patency is close to its trough) and had no effect around 1630 (peak time of airway patency) in both groups (P less than 0.01; ANOVA). Thus, inhaled orciprenaline was mainly effective around 0730 and to a lesser extent around 2230 whereas there was no detectable effect during the day (1230 and 1630).

Administration, Inhalation↗
PubMed1988

Diurnal rhythms in performance tests of school children with and without language disorders.

Time-of-day related changes on four tests used by speech therapists and four other performance tests, in addition to oral temperature, were documented in 16 school children (7-9 years of age). Six of them had language disorders and were receiving speech therapy. Children were synchronized with diurnal activity from around 0730 to around 2100 and nocturnal rest. For each child, at each test time point (e.g. 0900, 1100, 1530 and 1930) tests were performed three times, with two different speech therapists, in a random order, with only one session per day. Conventional methods (t-tested mean differences; ANOVA; correlation tests) were used for statistical analyses. Among 29 parameters (items) which were analyzed, only nine exhibited time-of-day related changes, mainly in speed to-perform measures. In most detected rhythms best performance occurred either at 1100 or at 1530 with no difference in subgroups except for the fastest performance of the sentence repetition test. With regard to the daily mean M, controls performed better than children with language disorders for the word (syllabic) repetition test (P less than 0.0004) but this was reversed for both computing and colouring skill tests (P less than 0.04 and less than 0.002). A difference related to sex (but not to language disorders) was observed in the Ms of speed in sign reproduction (P less than 0.0000) and sorting cards (P less than 0.01), with boys being faster than girls. In children, as in adults, time-of-day effects should be considered when the quantification of performance is desired.

Body Temperature↗
PubMed1987

Streptozotocin diabetes in rats after acclimation to cold environment.

To investigate the effects of acclimation to a cold environment on the alteration of glucose and fat metabolism in diabetes, the levels of blood glucose, triacylglycerol, nonesterified fatty acid, and immunoreactive insulin were measured before and on the 3rd and 14th days after streptozotocin treatment in cold-acclimated (4 degrees C) and warm-acclimated (24 degrees C; control) rats. The cold-acclimated rats showed no hyperglycemia on the 14th day after streptozotocin treatment, whereas the control diabetic rats maintained high blood glucose levels. Triacylglycerol levels did not increase in the cold-acclimated diabetic rats, whereas the control diabetic rats showed markedly high triacylglycerol levels. Immunoreactive insulin levels remained constantly low in both cold-acclimated and control diabetic rats. It was concluded that acclimation to cold changed some of the metabolic consequences of diabetes caused by streptozotocin in rats.

Acclimatization↗
PubMed1987

Circadian rhythm of serum total immunoglobin E (IgE) in asthmatic children.

Time of day related changes in serum total IgE (and cortisol as marker rhythm) were documented in 6 non-allergic children (2 girls, 4 boys, 6 to 10 years old) and 3 boys (10 to 14 years) with allergic asthma but symptom free at the time of the study. Subjects were synchronized with a diurnal activity from 07.00 to 21.00 and a nocturnal rest. Venous blood was sampled at fixed times (07.30, 11.30, 16.30 and 22.30) during a 24 hours span for the healthy children and during a 48 hours span for the asthmatics. Radioimmunoassay methods were used for the determinations. Time series were analyzed according to conventional (t tested differences, ANOVA) and Cosinor methods. No IgE circadian rhythm was validated in healthy children while a large amplitude (approximately equal to 30% of the 24 hours mean) circadian rhythm with 2 diurnal peaks and a nocturnal trough was demonstrated (P less than 0.0023) in the asthmatics. Therefore, time qualified references are needed for the interpretation of total IgE as they are for many biological variables. Circadian rhythm of IgE is presumably related to those of lymphocyte subpopulations such as B, T and T-suppressor cells.

Adolescent↗
PubMed1985

Interaction of trichloroethane isomers with cytochrome P-450 in the perfused rat liver.

The real-time interactions of 1,1,1-trichloroethane (TCE) and 1,1,2-TCE with cytochrome P-450 were observed using in vivo optical methods to measure the spectral changes of cytochrome P-450 and the reduction-oxidation transition of pyridine nucleotides in the perfused liver of rats treated with phenobarbital. Changes in oxygen consumption and TCE uptake were also measured. The spectral changes of cytochrome P-450 indicated that both TCE isomers bound to low spin (substrate free) ferric cytochrome P-450 and formed a high spin (substrate complexed) form. However, 1,1,1-TCE bound more tightly to cytochrome P-450 and seemed to be only slowly metabolized compared to 1,1,2-TCE. The stoichiometry of the change in oxygen consumption rate to the change in 1,1,1-TCE uptake rate ranged between 5/1 and 9/1, whereas that of 1,1,2-TCE was 1.4 to 2.0. Decreases in reduced pyridine nucleotides associated with TCE administration were significantly larger with 1,1,1-TCE than with 1,1,2-TCE. The inhibitory effect of 1,1,1-TCE on hexobarbital metabolism in the perfused liver was greater than that of 1,1,2-TCE. Considering our previous data indicating that TCE did not stimulate mitochondrial respiration, it is postulated that the far higher amount of oxygen consumption associated with the binding of 1,1,1-TCE to cytochrome P-450 than the amount which was necessary to mixed-function oxidation of this compound was due to an uncoupling effect of 1,1,1-TCE on the mixed-function oxidase system.

Animals↗
PubMed1985

Direct effect of carbon monoxide on hexobarbital metabolism in the isolated perfused liver in the absence of hemoglobin.

The interaction of carbon monoxide (CO) with cytochrome P-450 associated with hexobarbital metabolism was observed in hemoglobin-free perfused rat liver by using a scanning reflectance spectrophotometer. The evidence obtained showed that CO bound to the substrate complexed cytochrome P-450 and, at a CO/O2 ratio of over 0.1 in the perfusate, inhibited the hexobarbital metabolism estimated from the hexobarbital uptake, and oxygen consumption. Although the oxygen supply to the liver cell was one of the major limiting factors during CO hypoxia, CO binding to cytochrome P-450 significantly enhanced the suppression of hexobarbital oxidation caused by hypoxic hypoxia.

Animals↗
PubMed1984

Effect of ethanol on uptake of trichloroethylene in isolated perfused rat liver.

The effect of ethanol on uptake of trichloroethylene in isolated perfused rat liver was investigated. The uptake of trichloroethylene was measured in both phenobarbital (PB) non-treated and PB treated rat livers. Furthermore, for PB treated rat livers, the fluorescence of reduced pyridine nucleotides, oxygen consumption, and scanning reflectance spectrum were measured in the liver, perfused with Krebs-Henseleit buffer saturated with a 92%O2-5%CO2-3%CO gas mixture. The uptake of trichloroethylene was decreased by 6.0% in the PB non-treated rat liver and 10.6% in the PB treated rat liver following the addition of ethanol. This uptake decrease was thought to arise mainly from the inhibitory effect of ethanol on mixed-function oxidation in the liver because of the corresponding decrease in oxygen consumption and absorbance difference delta A450-490nm. The inhibition was considered to be due to interference with electron transfer to the complex of substrate and cytochrome P-450. Increase in intracellular NADH might also affect the formation of trichloroacetic acid since the reduction of NADH in the cytosol attained a maximum with 20 mM ethanol.

Animals↗
PubMed1983

Additive effect of nitrogen oxides and cold stress on circulating leukocyte counts in rats.

To study the combined effect of nitrogen oxides (NOx) and cold stress on circulating leukocyte counts, the numbers of total leukocytes, neutrophils, lymphocytes, and eosinophils were counted in rats after 3 h exposure to NOx and/or cold stress. There was a tendency for both NOx and cold stress to increase the total leukocyte count and the neutrophil count, and to decrease the eosinophil count. The data indicated that the effects of NOx and cold stress were additive when they acted simultaneously.

Animals↗