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Biomedical subjects

S Shinkai

Publications and source records attributed to S Shinkai.

At least 73 records · Page 4Linked to original sources
PubMed1993

Relationships between health status and working conditions and personalities among VDT workers.

A total of 486 visual display terminal (VDT) workers were surveyed on their health status, working conditions, type A state, and depression state through questionnaires. They were also divided into three groups by self-assessment: technocentered (TC), technoanxious (TA), and neither (N). The weekly working hours and daily VDT operating hours of the type A group were longer than those of non-type A group. Type A subjects had more symptoms than non-type A subjects. The mean weekly working hours of depressive group was 61.3 hr, much longer than that of the others. The TC subjects worked daily with the VDT for longer hours than the other subjects. The TA subjects felt most dissatisfied with their computer training (TC, 47.4%; N, 64.5%; TA, 91.7%). Awkward VDT operators were more often in the TA group (36.1%) than in the others (TC, 3.8%; N, 10.5%). The TA subjects had a higher previous history of duodenal ulcer than the others (TA, 13.9%; N, 4.6%; TC, 3.8%).

Adolescent↗
PubMed1993

Salivary cortisol for monitoring circadian rhythm variation in adrenal activity during shiftwork.

To examine the validity of salivary cortisol for monitoring circadian rhythm variation in adrenal activity during shiftwork, saliva and blood samples were collected at 4-h intervals in experimental short-term shifts, i.e., day (work 0830-1600 h; sleep 0030-0800 h), evening (work 1630-2400 h; sleep 0430-1200 h), and night (work 0030-0800 h; sleep 1230-2000 h) shifts over 2 days. Cortisol levels, determined by radioimmunoassay, and the circadian profiles of saliva and sera were compared. The salivary cortisol showed relatively low levels, the 2-day mean value being 3.1%-3.3% that of serum total cortisol through all shifts. Significant differences in the serum to saliva cortisol ratios were noted among shifts and subjects. When expressed as a relative percentage of a 2-day mean value, however, salivary cortisol paralleled the modified circadian profiles of serum total cortisol of the evening and night shifts, with no significant time lag and no difference in magnitude. The cosinor analysis supported this finding. Thus, salivary cortisol appears to be an excellent measure for monitoring circadian rhythm variation in adrenal activity in healthy individuals during shiftwork.

Adrenal Glands↗
PubMed1993

[Physical fitness and energy metabolism of the elderly].

It is generally accepted that decreased lean body mass (LBM) with aging is responsible for decline in basal metabolism (BMR) of the elderly. However, multiple regression analysis of BMR and related factors for middle- to older-aged subjects showed that decline in BMR with aging could not be explained only by decrease in LBM. Basal heat production rates per essential body mass (EBM) and per fat tissue mass (FTM) by sex and by age class were estimated using the regression analysis proposed by Chirifu. It was found that the basal heat production per EBM decreased with aging, indicating that both decreases in active tissue mass and BMR per unit of active tissue mass were involved in reduced BMR for the elderly. A 15-week aerobic exercise training course prescribed for mildly obese middle- to older-aged women improved their fitness level and body composition, i.e., decrease in FTM with increase in EBM. The basal heat production rate per EBM increased by 21%. These results suggest that aerobic exercise training is effective for improving the metabolism of active tissue in the middle-aged and the elderly. Although there was a wide inter-individual variation in BMR in the elderly over 70 years of age, the BMR tended to increase depending on the level of daily activity. In conclusion, physical exercise and an active daily life are important for decelerating the decrease in BMR for the elderly through maintaining active tissue mass and its basal metabolism.

Adult↗
PubMed1993

Triathlon competition induced a transient immunosuppressive change in the peripheral blood of athletes.

This study was designed to determine whether or not physical and psychological stress of triathlon competition causes an immunosuppressive change in the peripheral blood of athletes, if it does occur, how long does it take to recover. Fifteen healthy men, aged 19 to 40, volunteered for this study. Peripheral blood was drawn four times at approximately the same time on the following days; one day before the race, immediately after, one day and eight days after, and served for determining circulating leucocyte and lymphocyte subset counts, in vitro lymphocyte proliferative response and natural killer activity. The results showed that triathlon competition caused considerable changes in the cell counts of peripheral blood leucocyte and lymphocyte subsets, and a transient reduction in vitro lymphocyte proliferative response and natural killer activity, all of which returned to pre-race levels in one to eight days after the race.

Adult↗
PubMed1992

The acute effects of experimental short-term evening and night shifts on human circadian rhythm: the oral temperature, heart rate, serum cortisol and urinary catecholamines levels.

This study was designed to examine the temporal changes in circadian rhythm of oral temperature, heart rate, serum cortisol and urinary catecholamines levels due to experimental short-term shifts. The six subjects were assigned to consecutive day (work 0800-1600 hours; sleep 0000-0800 hours), evening (1600-2400 hours; 0400-1200 hours), and night (0000-0800 hours; 1200-2000 hours) shifts of 2 days each scheduled as hospital shiftwork by nurses, in random order, during which data were collected every 4 h throughout the experimental periods. According to acrophases of a fitted cosine curve and visual inspection on chronograms, the phases of circadian rhythms were delayed to different degrees in the evening shifts with a minimum of about 1 h for oral temperature and a maximum of about 4 h for urinary free noradrenaline. The corresponding phase delays were larger in the night shift for oral temperature (about 3 h), resting heart rate (about 5 h) and urinary free noradrenaline (about 13 h); the diurnal variations of serum cortisol and urinary free adrenaline were greatly modified, and their circadian rhythmicities disappeared, indicating that the normal circadian phase relations of these variables were disrupted more by the night shift. The comparison of chronograms and correlation analyses revealed that the 4-h mean heart rate and urinary free noradrenaline were largely affected by rest-activity level in connection with shifts, while the resting heart rate and urinary free adrenaline were less affected. On the other hand, the sleep factor (time of onset and/or period) seemed to be more potent in modifying the circadian rhythm of serum cortisol, especially with the night shifts.

Adult↗
PubMed1992

Acute exercise and immune function. Relationship between lymphocyte activity and changes in subset counts.

Twenty-one young male subjects exercised on a cycle ergometer for 60 min at 60% of VO2max. Blood samples collected every 30 min throughout exercise and continuing to 120 min recovery served for the immunological tests. Exercise induced biphasic changes in the various leucocyte subsets. There was a granulocytosis, lymphocytosis and monocytosis during exercise, and a further granulocytosis and a slight monocytosis, but a lymphocytopenia during recovery. All lymphocyte subsets (CD3+, CD19+, CD4+, CD8+, and CD16+ cells) increased in number during exercise, were decreased 30 min after exercise, and had not returned to baseline levels by 120 min of recovery. The apparent lymphocyte responsiveness to the mitogens phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) declined significantly during exercise, returning to normal by 120 min of recovery. The natural killer (NK) activity rose markedly during exercise, but decreased to almost half the pre-exercise level at 30 and 60 min of recovery, returning to baseline levels after 120 min of recovery. Functional capability correlated well with the percentage of each major responder subset in the assay, suggesting that the in vitro lymphocyte PHA- and PWM-responsiveness and the NK activity did not change significantly on a per cell basis. The analysis of lymphocyte marker antigen density revealed that the CD3+, CD4+, CD8+ and CD19+ lymphocytes mobilized into the circulation during exercise did not express the respective CD3, CD4, CD8 and CD19 molecules as strongly as did the subsets circulating at rest, whereas the expression of the CD16 antigen on CD16+ lymphocytes remained unchanged.

Adult↗
PubMed1992

Effect of time of day on adaptive response to a 4-week aerobic exercise program.

The circadian effects of an aerobic training program were studied in 3 groups of men who exercised at different times of day. Twelve healthy sedentary men were assigned to morning (9:00-9:30), afternoon (15:00-15:30) or evening (20:00-20:30) exercise groups. Each group performed a 30-minute 60% VO2max cycle ergometer exercise 4 days per week over a 4-week period. Maximal oxygen uptake (VO2max) was estimated and adaptive responses of heart rate and blood lactate levels to the training program were measured. After 4 weeks, the afternoon group showed a significant increase in estimated VO2max. A significant decrease in heart rate and blood lactate responses occurred in the afternoon and morning groups and the afternoon and evening groups, respectively. These results suggest that aerobic training is most effective in the afternoon.

Adaptation, Physiological↗
PubMed1991

Structure of a photoresponsive crown ether, 21-(4'-methoxyphenylazo)-1,4,7,14,23-pentaoxa[7.2.2] orthometaorthobenzenophane.

3,10,13,16,23-Pentaoxatetracyclo-[23.3.1.0.(4,9)0(17,22)]nonaco sa-1(29), 4,6,8,17,19,21,25,27-nonaene-29-azo-(4'-methoxybenzene), C31H30N2O6, Mr = 526, monoclinic, P2(1)/n, a = 14.564 (3), b = 19.177 (2), c = 10.025 (2) A, beta = 100.42 (1) degrees, V = 2754 (1) A3, Z = 4, Dx = 1.269 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 0.95 cm-1, F(000) = 1112, T = 293 K, final R = 0.050 for 2577 reflections with I greater than 3 sigma(I). The molecule resembles a butterfly with benzene rings for the wings and head. The transazobenzene moiety, which overlays one face of the crown oxygen ring, is in an orientation that creates a partial steric block to cation...crown complex formation.

Ethers, Cyclic↗
PubMed1989

[Changes in temperature and humidity at different layers inside clothing during rest, exercise, and recovery].

This paper presents the results of experiments in which we measured humidity and temperature changes that took place in different layers inside and on clothing. The experiments were conducted during rest, exercise, and recovery. During each experiment, subjects wore one of three kinds of outerwear made of three different materials, respectively. These materials were nylon taffeta (N), nylon taffeta-Goretex-nylon tricot laminated fabric (G), and polyvinylchloride-coated plain cotton fabric (V). The subjects wore an undershirt and a T-shirt under the outerwear. The humidity and the temperature were measured in the following parts of each subjects' back: (1) the layer between the subject's skin and the undershirt (first layer), (2) the layer between the undershirt and the T-shirt (second layer), (3) the layer between the T-shirt and the outerwear (third layer), and (4) the surface of the outerwear (fourth layer). We also measured the sensation of comfort, the skin temperature, the oral temperature and the degree of sweating of the subjects. The experiments were conducted in a climatic chamber under conditions of 20.7 +/- 0.4 degrees C, 61.2 +/- 3.6% RH and 2.5 +/- 0.5 cm/sec. The results we obtained were as follows: 1) While the subjects kept still, little change of humidity was observed with time in all the four layers. When the subjects were in motion, humidity increased as they started sweating. After the exercise ended, the humidity reached its maximum and then gradually decreased. 2) When subjects kept still, there was no difference in humidity in all the four layers of the outerwear.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Comparative study on effects of 14- and 16-membered macrolides on gastrointestinal motility in unanaesthetized dogs.

Comparative studies on the effects of 14-membered and 16-membered macrolides on gastrointestinal motility were conducted in unanaesthetized dogs. Midecamycin acetate, a new 16-membered macrolide, and leucomycin, another 16-membered macrolide, did not disturb the gastrointestinal motility and no dogs showed any adverse effects. In contrast, erythromycin stearate, erythromycin ethylsuccinate and triacetyloleandomycin, 14-membered macrolides, caused adverse effects such as strong contractile motility, nausea, vomiting and diarrhoea. The adverse effects of macrolides on the gastrointestinal tract are related to their chemical structure.

Administration, Oral↗
PubMed1987

[Pharmacokinetics of arbekacin in dogs. I. Serum concentration and urinary excretion].

A new aminoglycoside antibiotic, arbekacin (HBK) was intramuscularly and intravenously administered to dogs in order to study its pharmacokinetics in comparison to amikacin (AMK). The results obtained are summarized as follows. Serum concentrations of HBK were well correlated with dose levels. The dose-serum concentration relationship with HBK was similar to other aminoglycoside antibiotics. Biological half-lives of HBK and AMK were both about 1 hour in dogs. This was also similar to other aminoglycoside antibiotics. There was no significant difference in peak serum concentrations between 1 hour intravenous infusion and intramuscular injection of HBK at 2 mg/kg in dogs. Repetitive administration of HBK to dogs at 2 mg/kg twice a day for 14 days did not affect its serum concentration and biological half-life. Urinary excretion of HBK in dogs in 24 hours after administration accounted for about 80-90%.

Aminoglycosides↗
PubMed1987

[Pharmacokinetics of arbekacin in dogs. II. The distribution of arbekacin in tissues].

A new aminoglycoside antibiotic, arbekacin (HBK) was intramuscularly and intravenously administered to Beagle dogs at a dose of 10 mg/kg to study its distribution into various tissues. The results obtained are summarized as follows. Biological half-lives of HBK in serum after intramuscular and intravenous injection were 1.15 hours and 1.00 hour after administration, respectively. These half-lives were similar to the results obtained in previous studies. Maximum concentrations of HBK in tissues and biological fluids after intramuscular injection were the highest in kidney followed by vagina, serum, urinary bladder, uterus, ovarium, lung, parotid gland, trachea, tonsil, gall bladder, pericardiac fluid, thymus, muscle, heart, liver, mandibular gland, bile, aqueous humor, pancreas, cerebrospinal fluid and brain, in this order. Maximum concentrations were found at 4 hours in trachea, aqueous humor and cerebrospinal fluid, and at 2 hours in pericardiac fluid. In other tissues and biological fluids, they were obtained at 0.5-1 hour. Maximum concentrations in tissues and biological fluids after 1 hour intravenous injection were the highest in kidney followed by serum, ovarium, vagina, lung, parotid gland, urinary bladder, uterus, spleen, thymus, pericardiac fluid, gall bladder, trachea, tonsil, heart, liver, pancreas, muscle, mandibular gland, bile, aqueous humor, cerebrospinal fluid and brain in this order. Maximum concentrations were found at 4 hours in trachea, cerebrospinal fluid and bile, and at 2 hours in pericardiac fluid. In other tissues and biological fluids, they were obtained at the end of the infusion. Maximum concentrations in these biological fluids after both intramuscular and intravenous injection were similar to serum concentrations except kidney, trachea, and other biological fluids.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoglycosides↗
PubMed1986

A rapid enzyme immunoassay for measurement of HBK in blood.

An enzyme immunoassay has been developed for the measurement of HBK (4-amino-2-hydroxybutylyldibekacin) a new semisynthetic aminoglycoside antibiotic. Antisera were raised in rabbits by immunization with HBK conjugated to bovine serum albumin (BSA). 3'-Eno-HBK conjugated to alkaline phosphatase (ALP) was used as an enzyme labeled antigen. The antibody-bound drug was separated from free using goat anti-rabbit IgG serum. The assay can be completed within one hr by co-incubating the first and the second antibody. The present immunoassay allows detection of 10 ng HBK per ml of serum, and is applicable for monitoring HBK level in blood. HBK concentrations in human sera were determined by the immunoassay during and after infusion and the levels were compared with those determined by high performance liquid chromatography (HPLC) and antimicrobial assay.

Aminoglycosides↗
PubMed1985

Trapping of reactive intermediates in enzymology. Exogenous flavin reduction during catalytic turnover of substrate by glyoxalase I.

Although but weak inhibitors of glyoxalase I under steady-state conditions, flavins are reduced by yeast glyoxalase I (lactoyl-glutathione lyase, EC 4.4.1.5) plus its substrate (the hemithiolacetal from glutathione and phenylglyoxal) during catalytic turnover. Studies with 10-ethylisoalloxazine showed that this flavin reduction was peculiar not merely to glyoxalase I's substrate, but was characteristic of the complete system, enzyme plus substrate undergoing catalytic turnover. Flavins are poor hydride-ion acceptors and the reduction observed most likely represents an oxidative trap of a transient carbanion formed in the glyoxalase I mechanism of action. Hydrophobic flavins were more efficient traps than the hydrophilic ones, and values of the Km for the phenylglyoxal: glutathione hemithiolacetal adduct measured by the flavin-reaction and by normal steady-state kinetics were closely similar. This argues that trapping has occurred of an enediolate ion (an enzyme-generated carbanion) still bound to glyoxalase I.

Animals↗