Biomedical subjects

S Watanuki

Publications and source records attributed to S Watanuki.

At least 37 records · Page 2Linked to original sources

PubMed1994

Effects of wearing compression stockings on cardiovascular responses.

To investigate the effects of wearing compression stockings on cardiovascular responses, the heart rate (HR), cardiac output (Q) measured by CO2 rebreathing method, and oxygen intake were measured at rest in a supine position for 40 min and standing position for 120 min. Six female subjects wore the compression stockings after 20 min of rest at supine position. The oxygen intake and ventilation showed no significant difference between with and without the stockings. Q at standing position was lower than that at supine position by an act of hydrostatic pressure. However this decrease was lower with stockings than that without stockings. The compression stockings used in this study might improve the venous return to the heart. However, the subjects complained of discomfort due to the high clothing pressure. In the second experiment, the authors estimated the minimum pressure required in improving the venous return. The subjects wore the trousers having two bladders inflated by air pressure. The trousers could compress the leg (contain the foot) and thigh individually. From the relationship between air pressure and Q, the estimated minimum pressures were 17 mmHg for the leg and 15 mmHg for the thigh.

Bandages↗

PubMed1994

Improvements on a design of girdle by using cardiac output and pressure sensation.

To improve the design of the girdle which was a type of compression clothing, two kinds of experiments were carried out. At first, the degree of blood disturbance from wearing the girdles was evaluated by the cardiac output (Q). Q was significantly decreased with normal and small sized girdle was not significant. The practical clothing pressure was the positions with small sized girdle was not significant. The practical clothing pressure was the highest at the groin. Therefore, the relationship between the pressure applied to the groin by the cuff and Q was investigated. Q decreased linearly with an increase in pressure. The estimated minimum pressure required in maintaining the blood circulation was 14.1 mmH. To restrain the clothing pressure below that value, the form and material of the form and material of the bandage attached to the groin were designed and then 4 types of trial models were made. The designed bandage, as compared with that of ready-made, has a large form of stretchable material and its length in contact with the groin line was long. Q did not decrease by wearing one of them at supine position and at supine position after the sitting position. Furthermore, subjective discomfort also decreased.

Adult↗

PubMed1994

Dark adaptation curve during body temperature decrease.

To investigate the effect of body temperature decrease which occurred along with cold exposure and menstrual cycle on visual acuity, the dark adaptation curve (DAC), heart rate (HR) and tympanic membrane temperature (Tty) were measured at thermoneutral (29 degrees C) and cold (15 degrees C) in both follicular and luteal phases in menstrual cycle. Tty at thermoneutral and cold exposure in follicular phase were significantly lower than those in luteal phase. The degree of decrease in Tty by cooling in follicular phase was not significantly larger than that in luteal phase. HR was decreased significantly by cooling in both phases, while the difference between the two phases was not significant. DAC during cold exposure was lower than that during thermoneutral condition in both phases. Furthermore, the curve obtained during cooling in follicular phase was lower than that during cooling in luteal phase. However, DAC obtained by a subject who showed an increase of Tty by cold exposure in both phases was higher than that at thermoneutral. Even in thermoneutral in luteal phase, DAC during head cooling was significantly lower than that during thermoneutral. These results suggest that the brightness sensitivity in scotopic vision might be increased by a decrease of body temperature and the light threshold during dark adaptation threshold may be related to the change of Tty.

Adult↗

PubMed1994

Effects of body temperature decrease on color sensation.

To investigate the effects of body temperature decrease which occurred along with cold exposure and menstrual cycle, on color sensation, differential limen (DL) and points of subjectively equality (PSE) or red, green, blue and gray colors were measured by using methods of limit in six young female subjects. also, the subjectively preferred complexion was selected. The lowest value in tympanic membrane temperature (Tty) was observed under the cold exposure condition at 15 degrees C in follicular phase. DL of gray obtained during cooling was significantly lower than that during thermoneutral condition in follicular phase. However, DL of green, red and blue were not changed by cold exposure in both menstrual phases. The Munsell value of subjectively preferred complexion selected during cooling was significantly lower than that obtained during thermoneutral condition in follicular phase. Compared with the distribution of Munsell hue of chips selected as preferred complexion in thermoneutral condition, the hue selected in cooling was not shifted to a more reddish one. These results suggest the possibility that brightness sensation rather than color sensation might be increased due to Tty decrease.

Adult↗

PubMed1993

Effect of lentinan on lymphocyte subsets of peripheral blood, lymph nodes, and tumor tissues in patients with gastric cancer.

The effect of lentinan on lymphocyte subsets of peripheral blood, lymph nodes, and tumor tissues in gastric cancer patients was investigated. A 2-mg dose of lentinan was administered to 12 patients intravenously twice, the first at 3-9 days before and the second the day before surgery. The results were then compared with a control group without lentinan administration comprising 12 patients. Regarding peripheral blood and lymph nodes without metastasis, lymphocyte subsets defined with anti-CD3, anti-CD4, anti-CD8, anti-Leu7, and anti-Leu11 were analyzed by flow-cytometry. As for tumor tissues, lymphocyte subsets defined with anti-CD3, anti-CD4, anti-CD8, anti-Leu11, and anti-M3 were analyzed after immunohistochemical staining. There were no significant changes in the lymphocyte subsets of peripheral blood between the two groups. In the lymph nodes, the CD4 cell ratios increased; otherwise in regard to tumor-infiltrating lymphocytes (TILs), the number of CD4, Leu11 and LeuM3 cells showed a prominent increase. Therefore, lentinan was observed to produce different effects in accordance with the subjective organs.

Aged↗

PubMed1993

6-[18F]fluorodopa metabolism in patients with hemiparkinsonism studied by positron emission tomography.

A group of 10 healthy control subjects and 10 patients with hemiparkinsonism (HD) were studied by positron emission tomography (PET) using 6-[18F]fluorodopa (FDOPA). FDOPA metabolism in the caudate nucleus and the putamen was separately estimated by measuring target-to-background ratios (TBRs) using composite images added between 30 and 60 min after FDOPA injection and by TBR-versus-time slopes during PET study. TBRs in the caudate nucleus and the putamen were 1.81 +/- 0.23 (mean +/- SD) and 1.92 +/- 0.28 in the 10 controls, respectively. In HD patients, on the dominantly affected hemisphere related to main clinical symptoms, TBRs were significantly decreased in the caudate nucleus (P < 0.01) and the putamen (P < 0.05) compared with those in the corresponding areas on the contralateral hemisphere, though those TBRs on both hemispheres were significantly decreased compared with the TBRs of normal subjects (P < 0.01). TBRs and TBR slopes in both the caudate nucleus and the putamen were correlated with disease severity according to Hoehn and Yahr. On the dominantly affected hemisphere, TBR and TBR slopes in the putamen were well correlated with individual clinical measures for bradykinesia and rigidity, and those in the caudate nucleus were also correlated with the severity of tremor. Our data suggest that in HD patients, PET study using FDOPA may provide unique and efficient information on the dysfunction of the dominantly affected caudate nucleus and the putamen which are correlated with diseased severity and individual clinical symptoms.

Adult↗

PubMed1993

[Studies on development of evaluation method for wood-based floors. Part 1. Evaluating the attenuational capacity of human locomotor system due to the acceleration at several parts of the human body].

Experiments were conducted to compare the impact on several parts of the body caused by the striking of the heel during human gait. In these experiments, five kinds of wood flooring that have differing levels of light weight-impact sound insulating efficiency were used. The obtained results were as follows: 1) The generated acceleration of calcaneus varied with the difference of flooring. According to the regression analysis, the open polygonal relationship between bound back coefficient of floor and acceleration of calcaneus was determined. 2) The impact force given to the calcaneus propagated from the heel to the forehead after most of the force being absorbed at the ankle and the knee. We found direct correlation between the subjective feeling of floor pliabilty and the force to the leg. Therefore, it was suggested that the measurement of the force to the ankle and the knee was important in evaluating the efficiency of floors.

Acceleration↗

PubMed1993

Effects of head cooling on cardiovascular and body temperature responses during submaximal exercise.

Cardiovascular and body temperature responses during submaximal exercise (25% and 50% VO2max) were investigated using female subjects (n = 6) in two separate experiments; one with head cooling and heating and the other with torso heating with and without head cooling. To supply the heat load, a liquid conditioned cap and vest were used. In the first experiment, a significant decrease in heart rate, oxygen intake (VO2) and cardiac output (Q) at relative work intensity of 50% VO2max was observed by head cooling. These results show that head cooling is very effective to reduce the physiological strain. In the second experiment, Q as a function of VO2 during torso heating was decreased by head cooling. However, the tympanic membrane temperature during head cooling at 15 degrees C was significantly higher than that at 20 degrees C and it was almost the same level with torso heating without head cooling. The results suggest that excess head cooling is not beneficial in terms of improving the body heat dissipation.

Body Temperature Regulation↗

PubMed1993

Endoscopic and clinicopathological features of primary gastric lymphoma.

Thirty-three patients with primary gastric lymphoma over a period of 32 years were studied. Endoscopic findings indicated that there were many cases of multiple lymphoma in the stomach, or with extensive tumor-infiltration, and that it was necessary to carefully inspect the entire stomach to determine the scope of resection and improve diagnostic accuracy. It is also particularly important not to damage the tissue during biopsy and to take deep large specimens from the ulcer margin, surrounding wall, and area of erosion. As compared clinicopathologically with gastric carcinoma, primary gastric lymphoma is found more frequently in younger females, with invasion of the entire stomach and extensive lymph node infiltration. By performing adequate resection of lymph nodes, as is done for gastric carcinoma, and administering appropriate combination chemotherapy, postoperative longterm results were similar to, or better than, those obtained with gastric carcinoma.

Adult↗

PubMed1992

[Physiological evaluation of clothing made of new material for protection against the solar heat load].

The purpose of this study was to evaluate the effects of clothing made of a new material that is, the polyester staple containing the ceramics and to reflect the solar heat load on physiological responses during rest, exercise (50% VO2max) and recovery on a cycle ergometer. Six young female subjects exposed their back to an artificial solar heat load of an intensity of 680 kcal/m2/h with an air temperature of 30 degrees C. The data were compared to those obtained by wearing clothing made of cotton material. The results were as follows. The cardiac output and oxygen consumption obtained at the end of recovery were increased by solar heat load when the subjects wore cotton material. However, these values showed no significant increase when the subjects wore solar heat reflecting clothing. Furthermore, the cardiac output at the end of submaximal work and recovery were higher for the cotton material compared to the heat reflecting clothing in the solar heat load. The increase of cardiac output for the cotton material may show the increase of skin blood flow for the body heat dissipation. Those results suggest that the solar heat reflecting clothing may decrease the physiological strain like a blood redistribution for the body heat dissipation during exercise in summer sunlight.

Adult↗

PubMed1991

Absorbed dose estimates in positron emission tomography studies based on the administration of 18F-labeled radiopharmaceuticals.

Absorbed doses were estimated after intravenous administration of 18F-labeled radiopharmaceuticals in Positron Emission Tomography (PET) studies. These radiopharmaceuticals, [18F]-2-Fluoro-2-Deoxy-D-Glucose (FDG), 6-[18F]Fluoro-L-Dopa (FDOPA) and 18F-5-Fluorodeoxyuridine (FdUR), are used in clinical research at the Cyclotron and Radioisotope Center of Tohoku University. Radiopharmaceutical biokinetic values were measured in humans or extrapolated from animal experiments. Selective organ uptake and rapid clearance of activity from the blood were observed. High activity in the bladder contents of humans was found. Calculations were made by the MIRD method, modified to account for the differences in physique and organ mass between the Caucasian Reference Man and the Japanese one. The bladder wall receives the highest dose (more than 1.23 x 10(-1) mGy/MBq) when any of these compounds are administered. Other organs receiving high doses are the heart, brain and kidneys from FDG; the kidneys and pancreas from FDOPA, and the kidneys and small intestine from FdUR. These organs received absorbed doses of more than 2.7 x 10(-2) mGy/MBq. Effective dose equivalents of 2.4 x 10(-2), 2.6 x 10(-2) and 3.3 x 10(-2) mSv/MBq were estimated in the intravenous administration of 18F-FDG, 18F-FDOPA and 18F-FdUR, respectively.

Adult↗

PubMed1991

Measurement of D2 dopamine receptor-specific carbon-11-YM-09151-2 binding in the canine brain by PET: importance of partial volume correction.

Carbon-11-YM-09151-2 binds highly selectively to D2 dopamine receptors in the brain. Using this ligand, D2 dopamine receptor density (Bmax) and affinity (Kd) in canine striatum were measured. After administering various doses of the ligand in nine experiments, regional uptake was followed by repeated PET scanning for up to 80 min. D2 dopamine receptor specific binding at equilibrium was defined as striatal minus occipital activity after partial volume correction. Bmax and Kd were estimated by Scatchard analysis to be 40.3 pmole/ml of tissue and 22.9 nM, respectively. When a low mass dose of the ligand was administered, the bound-to-free ligand ratio in the striatum at equilibrium was consistent with the Bmax/Kd value obtained from the Scatchard analysis. The present study demonstrates the importance of partial volume correction and the Bmax/Kd measurement in a single PET study with carbon-11-YM-09151-2.

Animals↗

PubMed1991

Estimation of absorbed doses in humans due to intravenous administration of fluorine-18-fluorodeoxyglucose in PET studies.

Radiation absorbed doses due to intravenous administration of fluorine-18-fluorodeoxyglucose in positron emission tomography (PET) studies were estimated in normal volunteers. The time-activity curves were obtained for seven human organs (brain, heart, kidney, liver, lung, pancreas, and spleen) by using dynamic PET scans and for bladder content by using a single detector. These time-activity curves were used for the calculation of the cumulative activity in these organs. Absorbed doses were calculated by the MIRD method using the absorbed dose per unit of cumulated activity, "S" value, transformed for the Japanese physique and the organ masses of the Japanese reference man. The bladder wall and the heart were the organs receiving higher doses of 1.2 x 10(-1) and 4.5 x 10(-2) mGy/MBq, respectively. The brain received a dose of 2.9 x 10(-2) mGy/MBq, and other organs received doses between 1.0 x 10(-2) and 3.0 x 10(-2) mGy/MBq. The effective dose equivalent was estimated to be 2.4 x 10(-2) mSv/MBq. These results were comparable to values of absorbed doses reported by other authors on the radiation dosimetry of this radiopharmaceutical.

Adult↗

PubMed1990

Stability of cerebral blood flow and oxygen metabolism during normal aging.

Cerebral blood flow and oxygen metabolism in aged normal subjects were measured with positron emission tomography and their relationship with brain atrophy was evaluated. Brain atrophy progressed in a linear fashion during aging while cerebral blood flow and oxygen metabolism were well preserved. The finding suggests that brain atrophy is an aging process less dependent on cerebral blood flow and metabolism over the course of normal aging.

Aged↗

PubMed1989

Kinetic evaluation of 11C-1-aminocyclopentane carboxylic acid in rabbits bearing VX-2 tumors using positron emission tomography.

Tumor detection with 11C-1-aminocyclopentane carboxylic acid (11C-ACPC) showed that this amino acid has a high affinity for malignant tumors. We studied the kinetics of intravenously injected 11C-ACPC in the rabbit VX-2 tumor using positron emission tomography. Three female rabbits bearing VX-2 tumor in the thighs were used. High uptake of 11C-ACPC was seen in the tumor and liver. 11C-ACPC in plasma decreased rapidly after injection and its activity in the tumor increased with time. The kinetic evaluation of ACPC uptake into the tumor was performed using the unidirectional transport model. The average values of the transfer constant of 11C-ACPC for VX-2 tumor were 0.030 +/- 0.002 ml/min/g. This preliminary result may form the basis for a quantitative analysis of the in vivo distribution of 11C-labeled ACPC in tumors.

Amino Acids↗

PubMed1989

Effect of precooling on heat tolerance of resting men in a hot environment: comparison with seasonal effect on it.

Four healthy Japanese males volunteered as subjects. They were exposed to hot environment of 50 degrees C with 50% relative humidity for 61 minutes immediately after the precooling where they rested in a 10 degrees C for 30 minutes. Their physiological data were compared with that of a previous report (Iwanaga et al., 1983), in which we studied the physiological responses of the same subjects at rest in a 50 degrees C without precooling in summer and winter. After precooling (PC), all the four subjects completed heat exposure for 61 minutes. But without precooling in summer (NC), two of the subjects stopped heat exposure before 61 minutes because of hyperthermia. Rectal temperature (TR) was lower in PC than in NC before and during heat exposure. During heat exposure, TR in PC had risen at the 30th minute, but TR in NC at 20th minute. Whereas there was no difference in heart rate (HR) during heat exposure between summer and winter, in PC HR remained lower than in NC because rising time of HR was prolonged during heat exposure.

Acclimatization↗

PubMed1989

Quantitative evaluation of L-[methyl-C-11] methionine uptake in tumor using positron emission tomography.

Tumor uptake of L-[methyl-11C]methionine ([11C]Met) was assessed in six patients with brain tumors and three patients with lung cancer using positron emission tomography (PET). In arterial plasma samples taken at 5, 15, 30, and 60 min after injection, a fraction of [11C]Met was measured using high performance liquid chromatography in individual patients. Employing curve fitting, a history of [11C]Met activity was obtained as an input function. By means of sequential PET scannings and graphic analysis, uptake rate and distribution volume of [11C]Met in tumor tissue were calculated. In two studies irreversible uptake into the tumors was not seen when total plasma 11C activity was used as the input; however when [11C]Met plasma activity was used, definite irreversible uptake was seen, indicating tumor viability. In other studies, up to 24% underestimation of uptake rate was found. The present results demonstrated the importance of measuring [11C]Met in plasma for quantitative assessment of in vivo amino acid metabolism in tumors.

Adolescent↗

PubMed1988

Positron CT imaging of an impending stroke.

We present PET findings of a case of a transient ischemic attack which later progressed to cerebral infarction. Cerebral blood flow at the stroke focus in the right parietal cortex measured after a TIA attack and before stroke was as low as 24 ml/100 g/min with some increase in oxygen extraction fraction and blood volume. The condition was compatible with "misery perfusion". This case may be an example suggestive that the "misery perfusion sign" is a warning of impending stroke and its poor prognosis if left without appropriate treatments.

Aged↗