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Biomedical subjects

T Furuse

Publications and source records attributed to T Furuse.

At least 19 recordsLinked to original sources
PubMed2002

Adaptive response and the influence of ageing: effects of low-dose irradiation on cell growth of cultured glial cells.

PURPOSE: To examine the molecular mechanism of radiation adaptive response (RAR) for the growth of cultured glial cells and to investigate the influence of ageing on the response. MATERIALS AND METHODS: Glial cells were cultured from young and older rats (1 and 24 months). RAR for the growth of glial cells conditioned with a low dose of X-rays and subsequently exposed to a high dose of X-rays was examined for cell number and BrdU incorporation. Involvement of the subcellular signalling pathway factors in RAR was investigated using their inhibitors, activators, and mutated and knockout glial cells. RESULTS: RAR was observed in cells cultured from young rats but was not in cells from older animals. The inhibitors of protein kinase C (PKC) and DNA-dependent protein kinase (DNA-PK) or phosphatidylinositol 3-kinase (PI3K) suppressed RAR. The activators of PKC instead of low-dose irradiation also caused RAR. Moreover, glial cells cultured from severe combined immunodeficiency (scid) mice (CB-17 scid) and ataxia-telangiectasia mutated (Atm) knockout mice showed no RAR. CONCLUSION: The results indicated that PKC, ATM, DNAPK and/or PI3K were involved in RAR for growth and BrdU incorporation of cultured glial cells and RAR decreased with ageing.

Age Factors↗
PubMed1998

Morphological changes in the orbital surface layer muscle of the rabbit eye produced by botulinum toxin.

We quantitated the morphological changes in the orbital surface layer muscles in the rabbit following the single injection of botulinum A toxin. Experiments were performed in 9 white rabbits (1.6-3.0 kg). They were administered 5 units (5 rabbits) or 10 units (4 rabbits) of botulinum toxin injected into the superior rectus muscle of one eye. The diameter of myofibers of the orbital and intermediate layer zones was measured with an ocular micrometer on histological sections 3 days and 1, 3 and 5 weeks after injection. Quantitative changes were noted in the muscle fibers of the orbital surface layer zone following the injection of 10 units of botulinum toxin. At 1 week, the diameter of myofibers in the orbital layer was reduced, but it was increased at 5 weeks compared to that in the control eyes; in contrast, no change in the diameter of muscle fibers was found in the intermediate layer zone.

Animals↗
PubMed1997

Microvascular change of the anterior eye segment after tenotomy in the rabbit.

BACKGROUND: The microvascular changes secondary to anterior segment ischemia following tenotomy of the extraocular muscles have not been studied in the rabbit. METHODS: Using scanning electron microscopy of methyl-methacrylate ocular microvascular luminal castings, the anterior eye segment vasculature after tenotomy was documented and compared to that after occlusion of the bilateral long posterior ciliary arteries and that in the eyes that were not subjected to any surgical intervention. RESULTS: Five days and 1 week after the surgical intervention with tenotomy, microvascular change secondary to the anterior segment ischemia was not apparent, but 2 weeks after the tenotomy subtle evidence of ischemia such as new vessels in the iris was observed. Seven weeks after tenotomy, marked microvascular change was observed where corneal new vessels arose from the superior perilimbal arteries. In contrast, we found prominent microvascular changes 2 weeks after the occlusion of the long posterior ciliary arteries. CONCLUSIONS: Tenotomy of the rabbit eye causes microvascular change similar to that in occlusion of the long posterior ciliary arteries. This result suggests that the anterior ciliary artery of the rabbit contributes blood flow to the anterior eye segment and also has a stronger connection with the long posterior ciliary artery than previously reported.

Animals↗
PubMed1997

Comparison of surgical results of responders and non-responders to the prism adaptation test in intermittent exotropia.

The data for 94 consecutive patients with intermittent exotropia of basic type, ranging from 20 to 40 prism diopters (delta), who preoperatively wore neutralizing prisms for 3 to 5 days, were studied retrospectively. The surgery in 43 patients in whom the amount of increase of angle was 4delta or less was based on the original angle (Group A), while that in 51 patients in whom the magnitude of increase was 5delta or more was based on the increased angle of deviation (Group B). Patients with initial deviation less than 30delta and patients younger than 7 years of age showed an increase of deviation with prism correction. There were no significant differences in surgical results between the two groups at 1 year, and at 3 years; although at 3 years satisfactory motor alignment and binocular function for single vision at distance was higher in Group B than that in Group A.

Adaptation, Ocular↗
PubMed1996

Strabismus surgery in ocular myasthenia gravis.

We evaluated the efficacy of eye muscle surgery in 4 patients with ocular myasthenia gravis with troublesome diplopia. All patients were in remission and had shown a consistently stable angle of deviation for at least 6 months preoperatively. The extent of eye muscle surgery was based on the degree of deviation in the primary position, and conventional recession and resection procedures were performed in 3 patients and hang-loose recession with an adjustable recession in 1. Single binocular vision was obtained in 3 patients in the primary position without prism correction or compensatory head posture. Electron-microscopic studies on the eye muscle specimens obtained at strabismus surgery revealed non-specific degenerative findings for the muscle fibers and sarcomeric disorganization compared to that in a control extraocular muscle.

Adolescent↗
PubMed1995

The reliability of a video-enhanced Hirschberg test under clinical conditions.

PURPOSE: To examine the reliability and usefulness of a video-based Hirschberg test under clinical conditions. METHODS: The authors estimated ocular deviation in 87 patients with strabismus through automated analysis of corneal reflex displacement using a video refractor. The reproducibility of measurement, the comparison with the prism and alternate cover test (PACT), and the distribution of the Hirschberg ratio were investigated. RESULTS: The 95% limits of agreement of the video-based Hirschberg test evaluated by repeated measurements were +/- 0.18 mm (equivalent to +/- 2.2 degrees or +/- 3.8 prism diopters [PD] of calculated strabismic deviation) for the horizontal deviation and +/- 0.28 mm (equivalent to +/- 3.4 degrees or +/- 5.9 PD) for the vertical deviation. The 95% limits of agreement between the Hirschberg measures and the PACT were within +/- 7.8 degrees or +/- 13.7 PD. The average (+/- SD) Hirschberg ratio was 12.3 +/- 1.2 degrees/mm or 21.8 +/- 2.1 PD/mm. CONCLUSIONS: The video-enhanced Hirschberg measurement shows good reproducibility and ease of application, even in the testing of infants. In quantitative analysis, however, systematic measurement error resulting from intersubject variance of the Hirschberg ratio should be taken into consideration.

Adolescent↗
PubMed1995

Production of defective virus by terminally differentiated myotubes infected with Rous sarcoma virus.

The generally accepted concept that the replication of Rous sarcoma virus (RSV) is dependent on host cell DNA synthesis was reexamined. As the host we used terminally differentiated myotubes (MT), in which no cellular DNA synthesis is observed. As an extension of our previous study which indicated that RSV-infected MT produce various virus components, we examined viral particles produced by infected MT. Electron microscopy showed presence of viral particles released from infected MT. Immunoprecipitation analysis revealed that these particles contained an equal amount of the gag but a decreased amount of the env proteins as compared with the particles from infected chicken embryo fibroblasts (CEF). Consequently, viral particles from infected MT had an infectivity only 6% of that of particles from infected CEF cells. In a parallel experiment, we microinjected molecularly cloned RSV DNA into MT. In contrast to the infection mediated by viral particles, both MT and CEF cells produced the same amount of infectious particles when microinjected with viral DNA. We conclude that RSV replicates in the complete absence of host DNA synthesis, though infectivity of the progeny virus depends on the initial condition of the infection.

Animals↗
PubMed1994

Critical period for restoration of normal stereoacuity in acute-onset comitant esotropia.

We conducted a retrospective study of 25 patients with acute-onset comitant esotropia to evaluate whether the timing of the start of treatment is a critical factor in the development of normal stereopsis. The mean age at onset was 12 years 4 months, and mean age at the start of treatment was 17 years 9 months. Bifixation was defined as a stereoacuity threshold score that was numerically lower than 60 seconds of arc on stereotesting. An operation was performed on the nonfixating eye for the prism-adapted angle. At the final examination, bifixation was observed in four patients (16%) with the Randot test and in 15 patients (60%) with the Titmus test. No relationship was found between the time of the start of treatment and the postoperative development of stereopsis, nor was there a significant (P > .10) difference between the two groups with early and delayed start of treatment in the proportion of patients with bifixation.

Acute Disease↗
PubMed1994

Extraocular muscle surgery in a rabbit model: site of reattachment following hang-back and conventional recession.

To determine the precise site of reattachment of recessed muscles, 4-mm conventional and hang-back recessions of the inferior rectus muscle were performed in 18 albino rabbits. Six weeks later, the distance from the anterior border of the reattached muscle to the insertion was measured both grossly and microscopically. In all cases the operated muscles had advanced minimally from the site of surgical placement. Gross observation showed that the mean forward creep was significantly greater for those rabbits which underwent hang-back recession (1.81 +/- 0.67 mm) than for those that were submitted to the conventional technique (0.83 +/- 0.38 mm). Measurements done on histological sections revealed that the mean distance of the anterior border of the muscle fiber from the reference suture was larger for conventional recession (2.73 +/- 0.75 mm) than for hang-back recession (1.91 +/- 0.72 mm).

Animals↗
PubMed1994

Intraoperative adjustable suture surgery for bilateral superior oblique palsy.

BACKGROUND: The modified Harada-Ito procedure has been reported to be an effective treatment for correction of cyclotorsion in bilateral superior oblique palsy. However, there are no reports regarding its use in intraoperative adjustable suture surgery. METHODS: The authors performed a retrospective study of 12 patients with traumatic bilateral superior oblique palsy who were classified as having either symmetric or asymmetric palsy according to the symmetry of the alternate hyperdeviation on side gazes. Cyclotorsion and vertical and horizontal deviation in the nine diagnostic positions were measured preoperatively and postoperatively. RESULTS: Of the 12 patients, 6 were determined to have symmetric palsy and 6 asymmetric palsy. Intraoperative adjustable suture surgery with the modified Harada-Ito procedure was performed bilaterally in the six patients with symmetric palsy and unilaterally in those with asymmetric palsy. The median measured value of extorsion in the primary position was reduced from 14.5 degrees to 2.5 degrees in patients with symmetric palsy and from 9.5 degrees to 2.0 degrees in those with asymmetric palsy. In downgaze, some degree of residual extorsion remained, and there was no significant change in esodeviation after surgery. In five patients with symmetric palsy and in all of those with asymmetric palsy, normal single binocular vision in the primary position but did not that in downgaze was restored after surgery. CONCLUSION: Intraoperative adjustable suture surgery is an effective treatment in correcting torsion, but may not be as effective for esodeviation in downgaze.

Adult↗
PubMed1993

The effects of aging on the function of alveolar macrophages in mice.

In order to determine whether the function of alveolar macrophages (AM) is modulated by aging, we measured the TNF-alpha production, phagocytic function, and surface antigen expression of AM from young and old mice. When AM were primed by IFN-gamma (500 units/ml) and triggered by LPS (100 micrograms/ml), TNF-alpha production by AM was significantly smaller in old mice as compared with young mice (young mice: 161.7 +/- 28.2 units/ml; old mice: 89.3 +/- 13.6 units/ml, P < 0.05). The percentage of AM which phagocytosed latex particles (more than one particle) in old mice was significantly lower than in young mice (young: 78.1 +/- 2.5%; old: 62.8 +/- 3.4%, P < 0.05). Ia antigen expression of the AM was significantly higher and asialo-GM1 antigen expression was significantly lower in old mice than in young mice (Ia: young, 0.030 +/- 0.005; old, 0.092 +/- 0.024, P < 0.05; asialo-GM1: young, 0.-9 +/- 0.01; old, 0.75 +/- 0.07, P < 0.01). These results suggest that alveolar macrophage function is at least decreased in part with aging in mice.

Aging↗
PubMed1988

Two cases of coronary artery spasm induced by indocyanine green.

There is no evidence in the literature that coronary artery spasm is induced by indocyanine green (ICG). In the present report, we describe 2 cases who developed chest pain with transient ST elevation on electrocardiograms after intravenous administration of ICG.

Aged↗
PubMed1987

Usefulness of Q-wave response to exercise as a predictor of coronary artery disease.

In lead CM5, the Q-wave response to exercise has been reported as an effective index in predicting coronary artery disease (CAD) and CAD with left anterior descending (LAD) disease. The purpose of this study was to verify these findings when the Q wave was analyzed in lead CC5 in 135 patients. The sensitivity for abnormal ST depression was 77%, specificity 83% and predictive value 78%. The corresponding values for the abnormal Q-wave response (reduction or no change in Q-wave amplitude) were 70%, 61% and 59%. These differences (except sensitivity) were significant. When either a positive ST or Q-wave response was used, sensitivity, specificity and predictive value did not significantly increase compared with the ST segment alone. In addition, only 45% of normal subjects with false-positive ST depression had a normal Q-wave response (increase) and 57% of patients with false-negative ST responses had an abnormal Q-wave response. When a positive response for CAD with an LAD lesion and for multivessel CAD with LAD narrowing was defined as having a Q-wave reduction, the sensitivities were extremely low (15% and 17%), but both the specificities and the predictive values were 100%. Therefore, the Q-wave analysis in lead CC5 is no more sensitive for detecting CAD than the ST-segment response. However, when a decreased Q-wave amplitude is observed, multivessel CAD and LAD narrowing can be predicted.

Coronary Disease↗
PubMed1987

Inhibitory action of 711389-S on the electrical activity of rabbit sinoatrial node.

The effects of 711389-S (0.1-10 mumol.litre-1) on membrane potentials and currents of rabbit sinoatrial node preparations were studied using a conventional double microelectrode voltage-clamp method. The agent 711389-S decreased the heart rate, the maximum rate of depolarisation, and the amplitude of the action potential and increased the action potential duration in a dose dependent manner. The slope of the diastolic depolarisation was also reduced. Of the current systems of sinoatrial node, 711389-S depressed the slow inward current (Isi), the potassium outward current (IK), and the hyperpolarisation activated current (Ih) dose dependently. The kinetics of IK were not altered significantly by the drug. It is concluded that 711389-S does not have an effect on a single current system but that the drug exerts a depressant effect on the electrical activity of the sinoatrial node.

Animals↗
PubMed1987

A case of four coronary artery fistulae originating from three vessels associated with aneurysm.

A case of an aneurysm associated with four coronary artery fistulae originating from three vessels is reported. The patient, a 52-year-old woman, had chest heaviness and palpitations. Coronary arteriography revealed the four fistulae originating from three coronary vessels with an aneurysm draining into the left ventricle and the main pulmonary artery. The patient's symptoms were relieved after fistulectomy and the aneurysmectomy, suggesting that a coronary steal phenomenon through the fistulae was the cause of her symptoms. This case is of interest because of its rarity, since this is the first case report of an aneurysm associated with four coronary artery fistulae from three vessels.

Arterio-Arterial Fistula↗
PubMed1987

Estimation of catecholamine potencies on the myocardium by means of a new method.

A simple method is described for evaluating the potencies of catecholamines on the slow response of myocardium. Catecholamines depolarize guinea pig ventricular muscle cells exposed to the high K+ (27 mmol/l) Tyrode's solution containing 0.2 mmol/l Ba through an increase in slow channel conductance. Higher concentrations of catecholamines in addition induce spontaneous action potentials. This model was used to estimate and compare catecholamine potencies on myocardium. Catecholamine concentrations needed for depolarization alone or for depolarization plus automatic activity were taken as basis for comparison. The order of potency obtained by means of this new method was: l-isoproterenol greater than l-adrenaline greater than or equal to dl-noradrenaline greater than or equal to dobutamine greater than or equal to dopamine. This is similar to the order reported with other methods.

Action Potentials↗