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Biomedical subjects

H Yamane

Publications and source records attributed to H Yamane.

At least 109 records · Page 6Linked to original sources
PubMed1995

The emergence of free radicals after acoustic trauma and strial blood flow.

The effect of acoustic trauma on cochlear strial circulation was investigated immunohistologically in the guinea pig. Kanamycin was used as a tracer of blood flow. Moreover, histochemical examinations were made to reveal the emergence of free radicals in the cochlea following acoustic trauma. At 5 min (5 min after intense sound exposure 120-125 dB SPL, 3 h) the blood flow in the stria vascularis was greatly diminished. At 2 h the strial blood flow started to recirculate and at 6 h it appeared to have returned to normal. Superoxide anion radicals (O2-) emerged along the luminal membrane of the marginal cells of the stria vascularis at 5 min. O2- disappeared at 30 min, but reappeared at 2 h. The cause of its emergence at 5 min was obscure. However, the strange phenomenon that O2- emerged again at 2 h seemed ascribable to the re-circulation of strial blood flow after sound exposure.

Animals↗
PubMed1995

Natural killer cell response in the inner ear.

Heterologous tumor cells (human chronic myelogenous leukemia K-562 cells) were injected into the perilymph and skin in guinea pigs in order to study the induction of NK cell activity in the inner ear. An in vitro transmission electron microscopic and immunohistochemical study showed that K-562 cells were attacked by guinea pig large granular lymphocytes. K-562 cells injected through the round window membrane were found to be targeted by NK cells emerging from surrounding venules after 7 to 9 days. During this time morhological changes occurred in the organ of Corti and stria vacularis. These findings suggest that the inner ear response to foreign cells induces activation and invasion of NK cells which occur relatively late compared with those in other organs such as skin.

Animals↗
PubMed1995

In vivo regeneration of vestibular hair cells of guinea pig.

Recent studies have shown that inner ear sensory cells may regenerate in mammals as well as in birds. In this in vivo study we investigated the regeneration of vestibular hair cells in guinea pigs after gentamycin intoxication, and found that the vestibular sensory epithelia reproduced new hair cells 30 days after degeneration, due to 30 consecutive days of gentamycin treatment. From the regeneration pattern of sensory epithelia, the supporting cells were identified as the progenitors of hair cells.

Animals↗
PubMed1993

Inner ear damage due to lipoid nephrosis.

Inner ear pathology was studied in adult rats with lipoid nephrosis induced by puromycin aminonucleoside. Although no abnormality was observed in auditory brain-stem responses, significant changes were noted in the stria vascularis. The most striking observation was that intermediate cells were markedly swelled, there-by pressing adjacent marginal cells. Severely affected marginal cells have vacuoles and increased lysosomes and protruded toward the endolymphatic space. The organ of Corti remained virtually intact. Although the vestibular maculae were relatively normal, type I hair cells in the semicircular canal underwent a conspicuous vaculolization. These findings support a postulate that the inner ear is liable to damage in lipoid nephrosis.

Animals↗
PubMed1993

A motor-driven ventricular assist device controlled with an optical encoder system.

An electric motor-driven ventricular assist device has been developed for long-term use inside the body. The system is composed of a pusher-plate-type blood pump and an actuator consisting of an electrical motor and a ball screw. Cyclic change of the direction of motor rotation makes a back-and-forth axial movement of the ball screw shaft. The shaft, which is detached from the pump diaphragm, pushes the diaphragm via a pusher plate to eject blood during systole; blood is sucked by the diaphragm resilience during diastole. Using the output signals from a newly designed, incremental-type, miniature optical rotary encoder mounted inside the actuator, the input voltage of the motor is optimally controlled referring to the phase difference between the current position of the moving rotor and the electrical reference signal of the rotation generated by a microprocessor-based controller. In vitro performance tests indicated that the system fulfills required specifications. The maximum efficiency was 11%, which was about twice as high as that obtained with the previous open-loop prototype system. In the air, the surface temperature of the actuator elevated to 20 degrees C above the room temperature. An acute in vivo test showed its feasibility as a left ventricular assist device. Analysis of the energy loss in each component of the system indicated that redesign and precise assembly of the mechanical parts could increase the system efficiency.

Algorithms↗
PubMed1993

[An adult case of anomalous origin of left coronary artery from pulmonary trunk: left coronary artery blood flow after closing of origin of left coronary artery].

An adult case of anomalous origin of left coronary artery from pulmonary trunk was reported. The catheterization studies revealed significant amount of left to right shunt in the pulmonary trunk and anomalous origin of left coronary artery from pulmonary artery with well developed and marked tortuously dilated collaterals from the right coronary artery. During surgery, blood flow waveforms of the LAD was measured using pulsed Doppler velocimeter. After temporary closing of the origin of left coronary artery, blood flow of the LAD markedly decreased. A-C bypass grafting to LAD was performed successfully using saphenous vein and graft flow rate was 220 ml/min. These findings suggest that the coronary blood flow through the tortuously dilated collaterals after ligation of the origin of left coronary artery was insufficient to perfuse the left coronary artery.

Adult↗
PubMed1992

Surface glycoprotein of human natural killer cells recognized by wheat germ agglutinin.

We analyzed surface glycoproteins of human natural killer (NK) cells by utilizing lectins. Among the lectins tested, wheat germ agglutinin (WGA) was found to bind preferentially to CD16(Leu11)-positive lymphocytes as determined by two-colour flow cytometry. Analysis of glycoproteins in the lysate prepared from NK cells with sodium dodecyl sulfate (SDS) gel electrophoresis followed by Western blotting and 125I labeled WGA staining revealed that a glycoprotein with an M(r) of 65 kDa was strongly bound to the lectin, but no corresponding glycoprotein was detected in the lysate of T lymphocytes. This glycoprotein (GP65) gave several spots in the pI range 4.1-4.6 on 2-dimensional gel electrophoresis. Sialidase treatment of GP65 resulted in a single spot on the 2-dimensional gel, suggesting that GP65 is heterogeneous in the degree of sialylation. GP65 was shown to be exposed on the cell surface, since it was radiolabeled with 125I by the lactoperoxidase-catalyzed method. We next isolated GP65 from human peripheral blood lymphocytes by a combination of chromatography on a cation-exchange column and a WGA-agarose column and preparative SDS gel electrophoresis. It is suggested that GP65 is a novel surface glycoprotein on human NK cells.

Chromatography, Affinity↗
PubMed1992

Metabolism of ent-Kaurene to Gibberellin A(12)-Aldehyde in Young Shoots of Normal Maize.

Young shoots of normal maize (Zea mays L.) were used to determine both the stepwise metabolism of ent-kaurene to gibberellin A(12)-aldehyde and the endogenous presence of the members in this series. Each of the five steps in the sequence was established by feeds of 17-(13)C, (3)H-labeled kauranoids to cubes from the cortex of elongating internodes, to homogenates from the cortex of elongating internodes, and/or to homogenates from dark-grown seedlings. The (13)C-metabolites were identified by Kovats retention indices (KRI) and full-scan capillary gas chromatography-mass spectrometry (GC-MS). Five substrates and the final product in this sequence were shown to be native by the isotopic dilution of 17-(13)C, (3)H-labeled substrates added as internal standards to extracts obtained from elongating internodes. Evidence for the isotopic dilution was obtained by KRI and full-scan capillary GC-MS. Thus, we document the presence in young maize shoots of the metabolic steps, ent-kaurene --> ent-kaurenol --> ent-kaurenal --> ent-kaurenoic acid --> ent-7 alpha-hydroxykaurenoic acid --> gibberellin A(12)-aldehyde.

Journal Article↗
PubMed1992

Coronary ostial endarterectomy in Takayasu's aortitis--confirmation of patency nine years postsurgically.

A case of Takayasu's aortitis with severe bilateral coronary ostial stenosis is reported. A transaortic coronary endarterectomy was performed and sufficient patency was confirmed angiographically 9 years after the operation. This is the first report of late coronary angiography after a transaortic coronary ostial endarterectomy in Takayasu's aortitis. The efficacy of this procedure for coronary ostial stenosis in Takayasu's aortitis is emphasized.

Adolescent↗
PubMed1992

[A case of periodic ataxia].

We report a sporadic case of periodic ataxia characterized by recurrent attacks of vertigo and ataxia. A 62-year-old male was known to have nystagmus at the age of 18. He has had recurrent episodes of vertigo and ataxia since the age of 48. During an attack remarkable downbeat nystagmus, limb ataxia predominant in the lower extremities and ataxic gait were present. MRI demonstrated an atrophy of the anterosuperior region of the cerebellar vermis. Vertical nystagmus, dysesthesia of gloves and stocking type and deep sensory disorder persisted during interictal intervals. There is no finding which supports this case to be vascular disorder, congenital anomaly, tumor, infection or demyelinating disease. We thought this case to be periodic ataxia and to belong to vestibulocerebellar ataxia reported by Farmer and his colleagues.

Cerebellar Ataxia↗
PubMed1992

[Choice of conduit in coronary bypass surgery].

Since 1987, arterial conduits have been used in 78 of 130 cases receiving coronary bypass surgery, including 25 treated by arterial conduits alone. The use of arterial conduits was mainly indicated to the anterior descending coronary artery (LAD), but the saphenous vein had to be used in 39 percent, 47 of 120 cases receiving bypass grafting to the LAD for various reasons including a combination of multiple obstructive arteriosclerosis, multiple bypass graftings in the aged, unstable angina, emergency operation and no suitable artery for a conduit as indicated by preoperative angiography. Hereafter, arterial conduits for coronary bypass grafting to LAD should be used in many more cases to the best possible advantage.

Adult↗
PubMed1992

[Coronary bypass surgery using arterial conduit and its pitfall].

Three patients with spasm of internal mammary arteries and gastroepiploic artery immediately after coronary bypass surgery were reported. On completion of the revascularization, all patients could not be weaned from cardiopulmonary bypass. The flow velocity waveforms of the arterial grafts measured by pulsed Doppler velocimeter showed only small systolic component without diastolic flow and the palpation revealed profound spasm partially in the arterial conduits. Although all patients could be weaned from cardiopulmonary bypass only after insertion of a saphenous vein graft, two of them died on the next day. In all patients, free flow measured prior bypass was considered to be sufficient and a technically satisfactory anastomosis was felt to be performed. If a profound hemodynamic instability as a result of intractable spasm of arterial conduit occurred after completion of coronary bypass surgery, an additional saphenous vein graft should be placed before discontinuation of cardiopulmonary bypass.

Aged↗
PubMed1992

[The influence of increase in heart rate on coronary flow dynamics in the patients with aortic stenosis].

To clarify the causative factors responsible for the development of effort angina in aortic stenosis, the influence of an increase in heart rate by atrial pacing and isoproterenol infusion on the phasic left coronary flow velocity waveforms were studied using a pulsed Doppler velocimeter during cardiac surgery. Coronary flow velocity waveforms in aortic stenosis was characterized by a slowly increased diastolic inflow and an elongation of the time from the onset of diastole to the diastolic peak velocity. An increase in heart rate by pacing brought about a marked decrease in diastolic coronary flow since the slowly increasing diastolic flow was cut with the onset of following systole. On the contrary, after an increase in heart rate by infusion of isoproterenol, diastolic increasing rate in the coronary flow waveform accelerated and diastolic peak velocity markedly increased. As the results, isoproterenol produced a significant increase in diastolic coronary inflow.

Aged↗
PubMed1992

[Four cases of aortic valve replacement in aortitis syndrome].

Four surgically treated cases of aortic valve regurgitation associated with the aortitis syndrome were reported. All patients were female and ranged in age from 38 to 51 years. In two cases, obstructive lesions of the aortic arch branch were seen in aortograms. Three patients had no inflammatory findings at the operation and one was operated on after improvement of inflammatory findings by steroid therapy. Aortic regurgitation was caused by annuloaortic ectasia, and aortic valve replacement was performed by the everting mattress suture method in all cases. One patient with stenosis of the left carotid artery, occlusion of the left subclavian artery, and hypertension died of extended cerebral damage due to suspected low flow cerebral perfusion during cardiopulmonary bypass. The other three patients are doing well 4 months to 11 years after surgery without paravalvular leakage. In cardiac surgery for the aortitis syndrome with an obstructive lesion of the aortic arch branch, deep hypothermic and high flow cardiopulmonary perfusion is required to prevent ischemic brain complications during surgery.

Adult↗
PubMed1991

Cochlear strial blood circulation.

The present immunohistologic study demonstrates that cochlear strial blood circulation is markedly damaged in guinea pigs subjected to intense acoustic stimulation. In contrast, autonomic unbalance of the inner ear induced by resection or electric stimulation of the superior cervical ganglion has no appreciable effect on cochlear strial blood flow. In consequence, although strial blood circulation in the cochlea is susceptible to pathological change in some conditions, it does not appear to be affected by autonomic unbalance alone.

Acoustic Stimulation↗
PubMed1991

Transplacental transfer of kanamycin to the embryonal or fetal inner ear.

Transplacental distribution of kanamycin (KM) to 35-60 day embryonal or fetal inner ear of the guinea pig following maternal treatment was investigated by an immunohistological technique. KM, administered at any stage of pregnancy, migrated through the placenta and entered into the cochlea. The drug pathway to the organ of Corti seemed to consist of two routes: the spiral vessels and the capillaries of the spiral limbus. However, at an early stage of pregnancy, KM was detected only slightly in the area corresponding to the stria vascularis, probably due to immaturation of strial capillaries.

Animals↗
PubMed1991

Morphological changes of the spiral vessel after rock music exposure.

Morphological changes of the spiral vessels of guinea pig after rock music exposure (110-120 dB SPL, 1-3 h) were investigated. Characteristic of rock music is an almost incessant sound production with narrow dynamic range, and high energy in the low tone area. Morphometrical study showed that the lumina of the spiral vessels have a tendency to dilate at all turns in 1-2-h-exposure groups, but tended to constrict, through only at the 2nd turn, in the group of 3-h exposure. This finding that early dilatation of the spiral vessels later turns into constriction may be one of the causes of noise induced temporary threshold shifts.

Animals↗