Biomedical subjects

K Hisashi

Publications and source records attributed to K Hisashi.

At least 19 recordsLinked to original sources

PubMed1999

Treatment of sudden sensorineural hearing loss with a continuous epidural block.

The efficacy of a continuous epidural block was evaluated in the treatment of 20 patients with sudden sensorineural hearing loss (SNHL). Ten patients were treated with continuous cervicothoracic epidural block (group A) and the other 10 were treated with stellate ganglion block (group B). No significant difference in factors affecting prognosis was noted between the groups. In the epidural block group 70% achieved substantial hearing improvement, while this occurred in only 30% of patients undergoing stellate ganglion block. These findings suggest that continuous epidural block can be effective in the treatment of sudden SNHL.

Adult↗

PubMed1999

Regulation of inner ear fluid in the guinea pig cochlea after the application of saturated NaCl solution to the round window membrane.

The regulation of K+ and Na+ in the inner ear fluid of the guinea pig was studied after the application of saturated NaCl solution to the round window membrane. K+ and Na+ activities in the scala tympani increased rapidly and then decreased. K+ activity in the scala media increased immediately, but Na+ activity continued to increase during the period of observation. K+ activity in the scala vestibuli continued to increase in the observation period. Na+ activity in the scala vestibuli increased and then decreased. The endocochlear potential decreased immediately to approximately 20% of its initial level. Total activities of K+ and Na+ increased immediately and then decreased in both the scala tympani and scala media. The total activity of K+ and Na+ increased slowly and showed no regulatory decrease in the scala vestibuli. Thus, changing patterns in the total activity of K+ and Na+ were similar for the scala tympani and scala media, but not for the scala media and the scala vestibuli. Different patterns of K+ and Na+ activities among the three scalae indicate that their mechanisms for regulating inner ear fluid differ.

Animals↗

PubMed1999

[Cutaneous polyarteritis nodosa associated with streptococcal infection in a child and a review of the literature].

Polyarteritis nodosa (PAN) is a multisystem inflammatory disease associated with necrosis of small and medium arteries. It can occur in a systemic form with manifestations in skin, joints, heart, nervous system, gastrointestinal tracts, lungs and kidneys. It is relatively rare in adults and even more in children. It may be divided into a cutaneous form (C-PAN) and a more generalized form (G-PAN). Usually C-PAN is thought to run a benign course. But some cases were reported to run chronic courses and be diagnosed G-PAN. It has been reported that some adults with PAN are related to HBV infection. On the other hand most children with PAN had upper respiratory infections some with streptococcal infections. We described a 5-year-old boy who was suffering from high fever, joint pain, subcutaneous nodular and livedo reticularis. We diagnosed him C-PAN by examination and clinical course. Anti-streptolysin O (ASO) and anti-streptokinase (ASK) increased and we suspected that C-PAN followed after streptococcal infection. We reviewed the literatures of C-PAN and streptococcal infection in childhood. Streptococcal infection has been implicated by a positive throat swab or an increase in ASO. There were 25 cases (75.7%) which were thought to be related with prior streptococcal infection in 33 cases. We thought that C-PAN may be associated with streptcoccal infection in childhood.

Child, Preschool↗

PubMed1998

Elevation of intracellular calcium induced by the intrapipette perfusion technique modifies membrane ion currents in the chick cochlear hair cell.

The concentration of intracellular calcium ion ([Ca2+]i) was altered in the same hair cell dissociated from a chick cochlea by the intrapipette perfusion technique. At a membrane potential of -40 mV, the elevation of [Ca2+]i generated outward-going currents within 60 sec when the intrapipette solution was based on KCl. In controls, at membrane potentials more positive than -50 mV, outward K+ currents were observed and at large positive potentials, the outward K+ current decreased, showing an N-shaped I-V relationship. This outward K+ current was increased by elevation of [Ca2+]i and was partially suppressed by a TEA-containing extracellular solution. We suggest that the Ca2+ increased by the intrapipette perfusion technique operates directly inside the cell membrane and activates Ca(2+)-activated K+ currents.

Animals↗

PubMed1996

Gadolinium blocks mechano-electric transducer current in chick cochlear hair cells.

We investigated the effects of gadolinium ion (Gd3+) on the mechano-electrical transduction (MET) current using a whole-cell patch electrode voltage clamp technique in dissociated cochlear hair cells of chicks. Gd3+ blocked the MET channel in a concentration- and voltage-dependent manner. At -50 mV, Gd3+ blocked the MET channel, with a Hill coefficient of 1.14 and a dissociation constant (KD) of 1.01 x 10(-5) M. Adaptation of the MET current disappeared after the introduction of Gd3+, a change that may be due to a decrease in inward going MET currents, specifically the Ca2+ component.

Animals↗

PubMed1996

[Sudden sensorineural hearing loss associated with anticardiolipin antibody].

We experienced three female patients with sudden sensorineural hearing loss. All the patients showed elevation of anticardiolipin antibody in the serum. Immunoglobulin (Ig) M anticardiolipin antibody was present in case 1 (a 34-year old woman). IgG anticardiolipin antibodies were present in cases 2 (a 50-year-old woman) and 3 (a 9 year old girl). The patient in case 1 showed hearing disturbance of low tone in the left ear and normal vestibular function in both ears. The case 2 patient had an average hearing level of 81.7dB at 0.5. 1, and 2kHz and severe canal paresis in the right ear. In case 3 the patient showed an average hearing level of 53.3dB in the right ear and normal vestibular function in both ears. It was suggested that thrombosis which might have been induced by anticardiolipin antibody could have caused the sudden sensorineural hearing loss in these patients. Steroid therapy cured the hearing disturbance completely in case 1. Steroid and prostaglandin E1 therapy did not improve the hearing disturbance in case 2. Steroid, prostaglandin E1, and ticlopidine hydrochloride therapy improved the hearing disturbance in case 3. It appears that not only steroids but also prostaglandin E1 and ticlopidine hydrochloride therapy may be effective in patients with sensorineural hearing loss associated with anticardiolipin antibody.

Acute Disease↗

PubMed1995

Cholesterol granuloma in the middle cranial fossa: report of two cases.

We report two cases of cholesterol granuloma in the middle cranial fossa. On CT the lesions appeared as a nonspecific, nonenhancing soft-tissue mass with bone erosion. On MRI they were seen as areas of high signal intensity surrounded by a low-intensity peripheral zone on both T1- and T2-weighted images. Cholesterol granuloma is thought to occur when pneumatised cells in the temporal bone become obstructed. Although this lesion usually occurs in the petrous bone, it can extend to the middle cranial fossa. The diagnosis and surgical management are discussed.

Adult↗

PubMed1995

Voltage-dependent Ca2+ channels in the spiral ganglion cells of guinea pig cochlea.

Voltage-dependent Ca2+ channels in spiral ganglion cells (SGCs) isolated from guinea pig cochlea were investigated using the patch-clamp technique in a whole-cell recording mode. The voltage-dependent Na+ and K+ currents were blocked by adding tetrodotoxin, 4-aminopyridine, and tetraethylammonium to the external solution and by using choline or Cs+ in the external and internal solutions instead of Na+ or K+, respectively. The depolarizing voltage steps evoked inward currents with slow current decay. The maximum amplitude of the inward current increased in a hyperbolic manner with increasing extracellular Ca2+ concentration, indicating that the inward current was a voltage-dependent Ca2+ current (ICa). In 5 mM Ca2+ external solution, the ICa activated from a membrane potential around -60 mV and reached full activation at about -10 mV. The ICa inactivated from about -60 mV and became fully inactivated at about O mV, consistent with the high-voltage-activated Ca2+ channel subtype. Ionic selectivities for Ca2+ channels in SGCs were as follows: Ca2+ > Ba2+ > Sr2+. Effects of both inorganic and organic Ca2+ antagonists also were examined. The inhibitory strength was as follows: La3+ > Cd2+ > Ni2+ > or = Co2+ for inorganic Ca2+ antagonists, and flunarizine > nicardipine > methoxyverapamil > diltiazem for organic ones.

4-Aminopyridine↗

PubMed1995

Disturbance of regulation of sodium by cis-diamminedichloroplatinum in perilymph of the guinea pig cochlea.

We studied the acute effects of cis-diamminedichloroplatinum (CDDP) on the cochlear partition and inner ear fluid in the guinea pig. At 48 hours after the administration of a single intramuscular injection of CDDP, 12.5 mg/kg of body weight, the endocochlear resting potential (EP) was significantly decreased to 32.1 +/- 1.8 mV in the treated animals, versus 80.6 +/- 1.0 mV in the control animals. There was a significant rise in potassium (K+), sodium (Na+), and chlorine (Cl-) in the endolymph of the animals treated with CDDP as compared with the control animals. Only Na+ was found to increase significantly in the perilymph, reaching more than twice the level of the control animals; both K+ and Cl- remained within the normal range. Serum electrolytes also remained within the normal range. Evaluation of modified ionic permeabilities across the endolymph-perilymph barrier showed an apparent increase in Na+ permeability and a normal range of K+ and Cl- permeabilities. Histopathologic examination of the cochlea showed a moderate collapse of the endolymphatic space, with atrophy of the stria vascularis and destruction of the outer hair cells. The findings suggest that the acute changes produced in the cochlea by administration of CDDP were attributable to a breakdown in the regulation of Na+ metabolism in the perilymph.

Animals↗

PubMed1995

[Steroid-responsive sensorineural hearing loss with low tone loss].

Five cases of sensorineural hearing loss of sudden onset were reviewed. They were not responsive to administration of ATP and Vit. B12, but very responsive to steroid administration. All the patients were male and showed hearing loss in low frequencies in pure tone audiogram. Administration of steroid recovered hearing impairment immediately. However, cessation of steroid aggravated the recovered hearing. Serological and immunological examinations did not show any abnormal findings on all the patients. It was considered that these five patients had characteristics of both steroid-sensitive and low tone-loss type sensorineural hearing losses.

Administration, Oral↗

PubMed1994

Potassium circulation in the perilymph of guinea pig cochlea.

To determine whether any differences exist in potassium circulation between the scala vestibuli and scala tympani, we recorded the change in K+ activity in both scalae of the guinea pig cochlea at the basal and third turns, using a double-barrelled, K(+)-sensitive microelectrode after perfusion with artificial perilymph containing 20 mM KCl and 130 mM NaCl. K+ activity increased immediately after the start of perfusion and decreased after its completion. The rates of decrease of K+ activities were approximately 1.0 mEq/l per min in the scala vestibuli of the basal and third turns, also 1.0 mEq/l per min in the scala tympani of the basal turn, and approximately 0.5 mEq/l per min in the scala tympani of the third turn. The rate of decrease of K+ activity in the scala tympani was significantly slower in the third turn than in the basal turn. Blockage of the cochlear aqueduct depressed the rate of decrease of K+ activity in the scala tympani more in the basal turn than in the third turn. These results suggest that there is a difference in potassium circulation between the scala vestibuli and scala tympani, and that the cochlear aqueduct plays an important role in potassium circulation in the perilymph of the scala tympani.

Animals↗

PubMed1994

The effects of ototoxic drugs on mechano-electric transduction channels in chick cochlear hair cells.

The effects of ototoxic drugs on mechano-electrical transduction (MET) currents were investigated in dissociated cochlear hair cells of the chick, using a whole-cell patch-electrode voltage-clamp technique. Dihydrostreptomycin (DHSM) and cisplatin (cis-dichlorodiammine platinum II, CDDP) blocked the MET channel in a dose- and voltage-dependent manner. In contrast, acetyl salicylate did not suppress the MET current. At -50 mV, DHSM and CDDP blocked the MET channel with a Hill coefficient of 0.93 and 2.1, respectively. These findings suggest that a single DHSM molecule or more than one CDDP molecule binds to a single MET channel.

Animals↗

PubMed1994

Coexistence of MALT-type lymphoma and squamous cell carcinoma of the larynx.

A 66-year-old Japanese man was diagnosed as having a MALT-type lymphoma by histopathological examination. The lesion involved the vocal folds bilaterally, occupying the larynx and extending beyond it, as shown by computed tomography (CT). A course of radiation therapy with moderate doses was given. Six months later, a squamous cell carcinoma was found in the larynx and total laryngectomy was then performed. The patient remained well, without recurrence, 46 months after the operation. thus, MALT-type lymphoma may coexist with a squamous cell carcinoma of the larynx.

Aged↗

PubMed1994

Single channel recordings of calcium currents in chick cochlear hair cells.

Single Ca2+ channel currents were recorded from chick cochlear hair cells by using cell-attached patches. The elementary current was about -2 pA at 70 mV positive to the resting potential (R.P.+ 70 mV); the slope conductance over a 40 mV voltage range was 24 pS. The open time histogram was reasonably well expressed by a single exponential function, while the closed time histogram was expressed by a sum of two exponential functions. The Ca2+ channel was activated around R.P.+ 60 mV and the average ensemble current did not decay during 130 ms depolarization, suggesting that the Ca2+ channel in chick cochlear hair cells is the L-type. The Ca2+ channel has three modes of gating behaviour, expressed as current records with brief openings (mode I), no openings (mode 0), or long-lasting openings and very brief closings (mode 2).

Animals↗

PubMed1993

Cisplatin blocks mechano-electric transducer current in chick cochlear hair cells.

The effects of cisplatin (cis-dichlorodiammine platinum II, CDDP) on the mechano-electrical transduction (MET) current were investigated with a whole-cell patch-electrode voltage clamp technique in dissociated cochlear hair cells of chicks. CDDP blocked the MET channel in a dose- and voltage-dependent manner. At -50 mV, CDDP blocked the MET channel with a Hill coefficient of approximately 2 and a dissociation constant (KD) of 1.5 x 10(-3) M. The kinetics of CDDP blockade consist of a voltage-independent and a voltage-dependent component.

Animals↗

PubMed1993

Mechanism of lack of development of negative endocochlear potential in guinea pigs with hair cell loss.

The endocochlear potential (EP), and the concentration of K+, Na+ and Cl- were measured simultaneously in endolymph of guinea pigs. The EP was 85.6 +/- 0.8 mV in normal guinea pigs, 90.7 +/- 0.8 mV in the kanamycin-treated animals, and 91.6 +/- 1.2 mV in those treated with nitrogen mustard-N-oxide (NMNO). Thirty minutes after the onset of anoxia, the EP (negative EP) was -29.3 +/- 1.0 mV in the normal group, -0.2 +/- 1.0 mV in the kanamycin-treated group, and -1.9 +/- 1.3 mV in the NMNO-treated group. The permeability coefficients of K+ (Pk), Na+ (Pna) and Cl- (Pcl) across the endolymph-perilymph barrier during the period of 20-30 min after the onset of anoxia in the normal group were (341.6 +/- 38.2) x 10(-9) cm3 sec-1, (53.0 +/- 8.1) x 10(-9) cm3 sec-1 and (111.8 +/- 27.2) x 10(-9) cm3 sec-1, respectively. Pk was decreased in the kanamycin- and NMNO-treated groups. Pna did not differ between the normal and treated groups. Pcl was increased in the kanamycin- and NMNO-treated groups. The K+:Na+:Cl- permeability ratio was 1:0.16:0.32 in the normal group, 1:1.12:11.6 in the kanamycin-treated group, and 1:0.44:5.60 in the NMNO-treated group. The results indicate that the lack of development of a negative EP in the kanamycin- and NMNO-treated guinea pigs was attributable to the increased Pcl and the decreased Pk across the endolymph-perilymph barrier, probably the organ of Corti, during anoxia.

Animals↗

PubMed1992

Interlay method for myringoplasty.

Sixty-nine ears with perforation of the tympanic membrane were reviewed. All had undergone myringoplasty by the interlay method. The average period for complete epithelization was 16.1 days after surgery. Neither blunting of the anterior tympanomeatal angle nor lateralization of the tympanic membrane was observed. The success rate was 94.2% for the initial surgery, when "success" is defined as closure of the perforation and complete epithelization (dry ear). The surgical technique and various advantages of the interlay method of myringoplasty are described.

Adolescent↗

PubMed1992

Importance of atticotomy in chronic otitis media with fixation of ossicles.

Seventy-seven patients with chronic otitis media were reviewed. Of the 77 patients, 42 underwent tympanoplasty with a columella, and 35 underwent myringoplasty and atticotomy. Twenty-five of the latter 35 patients showed less than 10 dB of hearing improvement with a patch test before operation. The ossicular chain was not disconnected in any of the 25 patients, but the mobility was severely restricted. It was interesting that fixation of the malleus was found at surgery in 80% (20/25) of the patients, whereas the stapes was immobilized in only 16% (4/25). Myringoplasty and atticotomy instead of tympanoplasty with a columella was sufficient to achieve hearing improvement in most of such cases. However, conventional atticotomy was not able to achieve improvement in the mobility of the ossicles because the mobility is usually severely restricted at the malleus. Removal of the anterior tympanic spine is the key to recovery of the mobility of the malleus, resulting in hearing improvement. Rate of success was obtained in 24 of 25 ears (96%).

Auditory Threshold↗