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Biomedical subjects

R Hayashi

Publications and source records attributed to R Hayashi.

At least 217 records · Page 12Linked to original sources
PubMed1990

[Coronary revascularization using an internal mammary artery-saphenous vein composite graft in a patient with severely calcified ascending aorta].

A 52-year-old woman with angina pectoris resulted from complete obstruction of left coronary ostium required double-vessel bypass. Because of severely calcified ascending aorta, avoidance of aortic cross-clamping was needed for the prevention of embolic injury and aortic dissection. Internal mammary artery (IMA)-saphenous vein (SV) composite graft under hypothermic ventricular fibrillation was successfully performed without any complication. IMA-SV composite graft is a good alternative in a case of insufficient IMA length and limited site for proximal vein graft anastomosis, which can avoid or reduce the manipulation of diseased ascending aorta.

Aortic Diseases↗
PubMed1989

Regulation of wrist stiffness by the stretch reflex.

In restoring the angular position after a displacement, the role of the muscle stretch reflex was investigated by comparing the restored angular torques and angular positions in the wrist under ischaemic and non-ischaemic conditions in normal human subjects. The wrist compliance (COM), defined as the dynamic relation between the angular position and the angular torque of the joint, was calculated to quantify the changes in the restoration of a displacement after abolishing the stretch reflex by ischaemia. The elasticity from the COM-function was found to be single most important factor controlled by the stretch reflex. The elasticity that equals the static stiffness of the system increased by more than 100%, from 0.21 Nm degree-1 with abolished reflex to 0.45 Nm degree-1 with intact reflex. Our results have shown that the stretch reflex assists in the rapid return of the limb to its original position after a mechanical displacement. When the reflex was blocked by ischaemia, the perturbation displaced the limb further away from the initial position.

Adult↗
PubMed1989

Evaluation of microencapsulated islets in agarose gel as bioartificial pancreas by studies of hormone secretion in culture and by xenotransplantation.

Islets were microencapsulated in agarose gel for examination of the possible use of microencapsulated islets as a bioartificial pancreas. Microencapsulated islets secreted insulin into the culture medium (RPMI-1640) and could rapidly increase their insulin release in response to a glucose challenge even after greater than 100 days. Hamster islets in groups of 400-1000 encapsulated in microbeads containing 11-14% (wt/wt) agarose were xenogenically transplanted into the peritoneal cavity of five diabetic mice. The longest normoglycemic period in these mice was 53 days, which was markedly longer than the normoglycemic period obtained by nonencapsulated islets. Agarose seems to be a suitable basic material for encapsulating islets, because the islets can easily be microencapsulated without any adverse effect on the islet function.

Animals↗
PubMed1989

[Diagnosis and treatment of dysplasia of the uterine cervix].

The accuracy of diagnosis and the results of treatment for dysplasia of the uterine cervix are analyzed. Three hundred and thirty-seven cases of mild, 231 of moderate and 200 of severe dysplasias have been treated at Kitasato University Hospital. By cytology 40.4% of mild, 74.5% of moderate and 89.0% of severe dysplasias were judged suspicious or positive, and the accurate cytopathological detection rate was 19.8%, 16.1% and 60.1%, respectively. Abnormal colposcopic findings such as M, P and W were observed in more than 95% of cases with dysplasia. The area of abnormal findings tends to be large as the lesion becomes more severe. Mild dysplasia progressed to cervical cancer in 1.5%, moderate dysplasia in 2.4% and severe dysplasia in 9.4%. Conservative therapy by laser vaporization or conization was used for 31 mild, 96 moderate and 114 severe dysplasias. The cure rate of each dysplasia was 100%, and pregnancy following laser therapy was encountered in 28 cases without abnormal course. It is concluded that colposcopy is more useful in diagnosis of mild and moderate dysplasia than cytology, and conservative laser treatment is an effective method for dysplasia.

Adult↗
PubMed1988

The influence of neuronal cells on the development of glutamine synthetase in astrocytes in vitro.

The influence of neurons on the development of astroglial cells was examined in vitro using glutamine synthetase (GS) activity as an index of metabolic maturation. The GS activity in forebrain astrocytes was significantly increased (about 70%) when they were co-cultured with forebrain neuronal cells. A similar effect was also observed when astrocytes from the immature septum, hippocampus or cerebellum were co-cultured with neurons derived from the septal-diagonal band region. The magnitude of the effect was not uniform; the cerebellar astrocytes, with relatively low GS activity, showed a greater (about 290%) quantitative response to the subcortical nerve cells than did the septal (about 115%) or the hippocampal (about 120%) astroglial cells. The addition of conditioned medium derived from neuronal cultures or plating the cells on a substratum of heat-killed nerve cells, elevated the GS activity of astroglial cells by 33% and 39%, respectively. Our results indicate that a trophic factor secreted by neurons and direct contact with the nerve cell matrix, are both involved in the regulation of the differentiation of astrocytes.

Animals↗
PubMed1988

The functional role of sensory inputs from the foot: stabilizing human standing posture during voluntary and vibration-induced body sway.

The functional role of sensory inputs from the foot in the stabilization of upright standing in humans was studied using an ischemic nerve block which was applied bilaterally at the level of the ankle. Subjects were asked: (1) to lean forward or backward by pivoting around their ankle joints; and (2) to hold a standing posture during the bilateral application of vibration (140 Hz) to the Achilles tendons. After 30-40 min of ischemia, the magnitude of maximum body leaning was equally reduced to about 70% of controls for both the "eyes-open" and "eyes-closed" conditions with bare feet. This decrease of body leaning caused by ischemia was not observed when a foot was fixed firmly on a "fixation" board. During vibration, body sway was augmented, and characteristic oscillations of this body sway around 3 Hz were observed under ischemic conditions with eyes closed and with bare feet. We concluded that foot sensation may be an important source of information for controlling the magnitude of body leaning and for stabilizing higher frequency components of body sway.

Adult↗
PubMed1988

Chest-wall reconstruction by contralateral latissimus dorsi musculocutaneous flap.

Reconstruction of chest wall and axilla are performed in 11 patients using a contralateral latissimus dorsi musculocutaneous flap. The entire lattisimus dorsi muscle, including the fascial portion, safely carried an island of skin from the area of the lumbodorsal fascia to the contralateral axilla. The flap was transposed to the defect through a tunnel between the pectoralis major and minor muscles. Most patients who needed reconstruction of the chest wall and axilla had compromised ipsilateral vasculature that prohibited its use in a pedicled flap but had an intact contralateral chest wall, axilla, and thoracodorsal vessels. Therefore, this procedure was performed easily in comparison with a free flap or pedicled omental flap. This is a new, valuable application for the versatile latissimus dorsi musculocutaneous flap.

Adult↗