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Biomedical subjects

H Katsu

Publications and source records attributed to H Katsu.

6 recordsLinked to original sources
PubMed2006

[Early results of new style aortosaphenous vein graft connector in coronary artery bypass grafting].

We retrospectively studied early clinical results of PAS-Port (PP) system. Fifty patients who underwent coronary artery bypass surgery with saphenous vein graft (SVG) from April 2004 to May 2005 were enrolled in this study. PP was tried for 36 SVGs in 32 patients. In 2 patients, SVG 4.0 mm in diameter could not be loaded into the device. In other 2 patients, anastomosis with PP was failed and followed by hand-sewing under aortic clamp or with Heartstring. Anastomosis with PP was successfully completed for 34 SVGs in 30 patients (group P) and conventional hand-sewing was performed for 23 SVGs in 20 patients (group C). The target vessels for SVG were similar between the 2 groups. No complication occurred in the use of PP. Postoperative angiography before discharge was performed for 31 SVGs in 27 patients (90.0%) in group P and 20 SVGs in 17 patients (85.0%) in group C. The patency rate of SVG was 96.8% in group P and 100% in group C. In conclusion, early results of PP were satisfactory compared with those of conventional hand-sewing. Severely sclerotic aorta and oversized SVG should be excluded because of possibility for incomplete deployment of the inner flange in PP.

Aged↗
PubMed2001

[The stress-reducing effect of cigarette smoking and the influence of trait-anxiety on its manifestation].

The purpose of the present study was to clarify the stress-reducing effect of cigarette smoking and the involvement of other factors such as trait-anxiety on the above effect of smoking. The subjects were 32 smokers who met DSM-IV criteria for substance dependence and 16 nonsmokers. The smokers were randomly assigned to a smoking group or a sham-smoking group. Immediately after the subjects performed a laboratory task, the State-Trait-Anxiety Inventory was administered for evaluating the levels of state-anxiety and trait-anxiety. The subjects were required to smoke a cigarette in a smoking group, sham-smoke in a sham-smoking group, or take a rest in a nonsmokers's group. After that, the same inventory was again administered. The decrease of state-anxiety in a smoking group was significantly more marked in degree than in a sham-smoking group and was comparable to that in a nonsmokers' group. A stepwise regression analysis revealed that the trait-anxiety levels significantly contributed to a decrease of state-anxiety levels in a smoking group. The present study indicated that cigarette smoking exhibited a stress-reducing effect and that the trait-anxiety levels were related to the effect of smoking.

Adult↗
PubMed2001

Selective 5-HT1A receptor agonist, 8-OH-DPAT, locally administered into the dorsal raphe nucleus increased extracellular acetylcholine concentrations in the medial prefrontal cortex of conscious rats.

The effects of a selective 5-hydroxytryptamine (5-HT)1A receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), directly administered into the dorsal raphe nucleus (DR) on acetylcholine (ACh) release in the medial prefrontal cortex (mPFC) of freely moving rats were investigated by using a microdialysis technique. 8-OH-DPAT (1.0 and 5.0 micrograms) administered into DR significantly increased extracellular ACh concentrations in mPFC in a dose-dependent manner with a maximal increase to 215% and 237% of basal level, respectively, whereas a 0.1 microgram dose of this drug failed to exert such an increase. The present study suggests that the stimulation of somatodendritic 5-HT1A autoreceptors in DR is involved in an enhancement in ACh release in mPFC.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1997

Circadian changes in body temperature during the menstrual cycle of healthy adult females and patients suffering from premenstrual syndrome.

The biological rhythm of females is closely related to the menstrual cycle, and this rhythm is believed to influence circadian changes in body temperature. This study investigated and compared the patterns of circadian changes in the body temperature of healthy adult females and patients suffering from premenstrual syndrome or major depression. Body temperature was measured both rectally and sublingually in healthy subjects, and only sublingually in the patients. During the luteal phase in healthy adult females, both the average and lowest nocturnal body temperatures increased, the amplitude of the circadian changes decreased, and the times of the lowest and highest temperatures within a 24-hour period were delayed by 2-3 h. In the patients, the amplitude decreased during disease periods, especially in the follicular phase, whereas in the luteal phase, circadian changes showed great variation each day, although the decrease in amplitude was not as remarkable. The results show that (i) the biological rhythm of females is intrinsically unstable in the luteal phase, although this rhythm is stable in the follicular phase; and, (ii) symptoms were often aggravated with the decreases in amplitude experienced in the luteal phase.

Adult↗
PubMed1996

Iterative correction method for shift-variant blurring caused by collimator aperture in SPECT.

A collimation system in single photon computed tomography (SPECT) induces blurring on reconstructed images. The blurring varies with the collimator aperture which is determined by the shape of the hole (its diameter and length), and with the distance between the collimator surface and the object. The blurring has shift-variant properties. This paper presents a new iterative method for correcting the shift-variant blurring. The method estimates the ratio of "ideal projection value" to "measured projection value" at each sample point. The term "ideal projection value" means the number of photons which enter the hole perpendicular to the collimator surface, and the term "measured projection value" means the number of photons which enter the hole at acute angles to the collimator aperture axis. If the estimation is accurate, ideal projection value can be obtained as the product of the measured projection value and the estimated ratio. The accuracy of the estimation is improved iteratively by comparing the measured projection vale with a weighted summation of several estimated projection value. The simulation results showed spatial resolution was improved without amplification of artifacts due to statistical noise.

Biometry↗