Biomedical subjects

T Takasaka

Publications and source records attributed to T Takasaka.

At least 109 records · Page 6Linked to original sources

PubMed1996

WGA lectin binding sites of the apical surface of corti epithelium: enhancement by back-scattered electron imaging in guinea-pig inner ear.

The apical surface of the guinea-pig organ of Corti was examined with SEM after WGA-lectin histochemistry which has a binding specificity for sialic acid and N-acetyl-glucosamine. The contrast of colloidal gold markers were particularly enhanced by back-scattered electron imaging. WGA lectin showed remarkable preference for the microvilli as well as flat surface areas in the supporting cells. Stereociliary surfaces and interstereociliary connections of the sensory hair cell were strongly labelled, whilst only rarely the markers were found in the flat areas of the apical surface of the hair cell. The connections, which are known to be involved in the initiation of the mechanoelectrical transduction, should consist of sialic acid and/or N-acetyl-glucosamine.

Acetylglucosamine↗

PubMed1996

Bilateral sensorineural hearing loss associated with the point mutation in mitochondrial genome.

Mitochondrial DNA (mtDNA) mutation associated with sensorineural hearing loss (SNHL) has previously been described in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and in aminoglycoside-induced deafness. The authors of this study report three cases of SNHL associated with mtDNA mutation (3243A-->G). They examined the clinical features of this type of SNHL by audiologic studies and examined the mtDNA mutation by the polymerase chain reaction technique. In the three cases described, the SNHL had an adult onset and was bilateral and symmetrical. All patients had adult-onset diabetes mellitus. Audiologic studies revealed that the SNHL in all patients derived from the cochlea rather than from retrocochlear sites. It is presumed that mtDNA mutation results in mitochondrial dysfunction in cochlear tissues (i.e., hair cells and stria vascularis) and in neurons of the auditory pathway. Genetic analysis of mtDNA offers new insight into the diagnosis and treatment of SNHL.

Adolescent↗

PubMed1996

Distribution of Ca2+ channels on cochlear outer hair cells revealed by fluorescent dihydropyridines.

Physiological evidence has shown that cochlear outer hair cells (OHC) possess L-type voltage-dependent Ca2+ channels through which Ca2+ enters the OHC during depolarization. Their subcellular distribution has, however, remained unclear. In this study, the distribution of L-type Ca2+ channels on the basolateral plasma membrane of OHC has been demonstrated by the use of a laser scanning confocal microscope (LSCM) and a fluorescent probe DMBODIPY-DHP. The fluorescent staining pattern on the basolateral wall is nonuniform, suggesting a heterogeneous distribution of the channels in the plasma membrane. Direct imaging of intracellular Ca2+ visualized in real time by means of the LSCM and the fluorescent Ca2+ probe fluo 3 revealed temporal and spatial integration of Ca2+ movements and Ca2+ channel distribution. Exposure to high-K+ solution induced heterogeneity in the subcellular increase in the intracellular Ca2+ concentration. These results suggest that the heterogeneous distribution of L-type Ca2+ channels on the basolateral membrane might induce heterogeneous intracellular Ca2+ distribution during electrical activity in the OHC.

Animals↗

PubMed1996

Culture and characterization of human nasal gland cells.

To study the regulation of ion transport by human nasal gland (HNG) cells, we developed a system for culturing HNG cells isolated by enzymatic digestion from human nasal polyps. When plated on flasks in media containing. Ultroser G serum substitute and a variety of growth factors, the HNG cells became confluent after 5-7 days. Cells were collected by trypsinization and replated at 10(6) cells/cm2 on porous filters. Confluent monolayers formed on days 3-5 after replating and were studied on days 5-7. Transepithelial resistance and short-circuit current (Isc) were 177 +/- 15 omega.cm2 and 12.2 +/- 1.3 microA/cm2 (means +/- SE, n = 35). Acetylcholine (ACh, 10(-5) M) induced a transient increase in Isc by 4.4 +/- 1.0 microA/cm2 when added to both apical and basolateral sides and returned to baseline levels within 5 min. Diphenylamine-2-carboxylate (10(-3) M) decreased baseline Isc by 30.2 +/- 1.7% (n = 6) and inhibited Isc responses induced by ACh. Amiloride also decreased baseline Isc by 12.3 +/- 3.4% (n = 6) but failed to inhibit ACh-induced Isc responses. ACh (10(-5) M) also induced an increase in intracellular Ca2+ concentration measured by fura 2-AM from 60.5 +/- 16.3 to 248.3 +/- 45.3 nM (n = 4). These findings suggest that gland cells from human nasal polyps can be grown in culture to produce epithelial cell sheets of high resistance, which secrete Cl- in response to cholinergic agent via an increase in intracellular Ca2+ concentration.

Adolescent↗

PubMed1996

IgA nephropathy with poorly developed lymphoepithelial symbiosis of the palatine tonsils.

Tonsillar abnormalities have been observed in patients with IgA nephropathy (IgAN). In addition, it has been suggested that reticulization of tonsillar crypt epithelium is important in tonsillar immunity. Therefore, we investigated reticulization of this area in patients with IgAN (14 cases) and compared results with those of control patients who exhibited recurrent tonsillitis or tonsillar hypertrophy (12 cases). Immunohistochemical staining of antikeratin antibody PKK1 was employed to visualize reticulization. Tonsils of controls showed well developed reticular crypt epithelia with lymphoepithelial symbiosis and the nonreticulated area was less than 7% of the total crypt epithelia per overall section. In IgAN tonsils, however, nonreticulated crypt epithelium was frequently observed and, in the advanced stage of IgAN, exceeded 50% of total crypt epithelia. The extent of glomerular damage in IgAN patients correlated significantly with the percentage of the area of nonreticulated crypt in palatine tonsils with a correlation coefficient of 0.91. Considered together with our finding that PKK1-positive epithelial reticular cells strongly expressed HLA-DR antigens in normal tonsils, the low level of reticulization in IgAN patients may induce the unusual immunity responsible for the pathogenesis of IgAN.

Adolescent↗

PubMed1996

Comparison of complications between endoscopic sinus surgery and Caldwell-Luc operation.

Endoscopic sinus surgery (ESS) was compared with Caldwell-Luc (C-L) operation based on blood loss during surgery, operation time, period of hospitalization and complications. Both blood loss and operation time were significantly reduced in ESS as compared with C-L operation. In addition, patients undergoing ESS resulted in discharges after surgery earlier than those undergoing C-L operation. Minor complication was seen in 4.8% of the ESS patients whereas no major complication was recognized. ESS is a relatively safe procedure with superiority over C-L operation.

Adolescent↗

PubMed1996

Carbohydrate composition of stereociliary glycocalyx of the utricle of guinea pig inner ear.

The carbohydrate composition of the stereociliary glycocalyx of the utricle was analysed quantitatively. The utricular sensory epithelium was collected from adult albino guinea pigs, and its apical surface structure was blotted onto a PVDF membrane, which was then subjected to acid hydrolysis. The hydrolysate was treated with 1-phenyl-3-methyl-5-pyrazolone for labelling and analysed by reversed-phase HPLC coupled with detection of UV absorbance at 245 nm. Man, GlcN, GaIN, Glc, Gal and Fuc were detected and estimated to be 211, 219, 46, 1,270, 266 and 36 pmoles per 10 utricular maculae, respectively. The presence of Man indicates the presence of N-linked glycoconjugates, and the considerable amounts of GLcN and Gal suggest the presence of complex-type N-glycosides, poly-lactosamine and/or keratan sulfate. The relatively low GaIN content indicates that O-glycosides, chondroitin sulfates and GaINAc-containing glycosphingolipids, i.e. gangliosides and globosides, are minor components. Electronmicroscopic and confocal laser scanning microscopic observations revealed that the blotted apical surface structure constituted mostly the ciliary bundle. Consequently, the observed carbohydrate composition is probably that of the stereociliary glycocalyx of the utricular sensory epithelium.

Animals↗

PubMed1996

Incidence of sniff-related cholesteatomas.

High negative middle ear pressure created by habitual sniffing in patients with insufficient closure of the Eustachian tube has been claimed by Magnuson and colleagues to be an important causative factor of acquired cholesteatomas. The present study was conducted to ascertain the rate and types of cholesteatomas in which habitual sniffing is involved. Among 105 consecutive patients with acquired cholesteatomas (112 ears: 93 flaccida type, 15 tensa type, 4 extensive type), 27 patients (31 ears) were diagnosed as having a habitual sniff in response to aural discomfort resulting from insufficient closure of the Eustachian tube. This corresponds to 25.7% of the patients, which is significantly higher than the prevalence of habitual sniffing in normal subjects, being 2 out of 130 (1.5%) (p < 0.005: chi2-test). Habitual sniffing was found to be statistically more common in flaccida-type than in the tensa-type cholesteatomas. Habitual sniffing in response to aural discomfort was thus found to be an important risk factor for cholesteatomas. However, investigations into other pathogeneses of cholesteatomas should be continued, since the sniff-related cases reported here were limited to one-fourth of the cases of acquired cholesteatomas studied.

Adolescent↗

PubMed1996

Measurement of endocochlear DC potentials in ears with acoustic neuromas: a preliminary report.

The pathogenesis of hearing loss in acoustic neuromas remains to be elucidated. To obtain more detailed information about inner ear damage in this disease, especially that dealing with the possibility of ischemia of the inner ear due to compression of the blood supply in the internal auditory canal by acoustic neuromas, measurement of endocochlear DC potential (EP) was attempted in three ears with acoustic neuromas during surgical removal of the tumors by the translabyrinthine approach. The size of each tumor was 3.0, 0.8, and 1.8 cm, respectively. An EP with a positive value was recorded in each of the three ears, i.e., 54, 57, and 38 mV, respectively, although the first and third patients were profoundly deaf on the side with a tumor. These findings were interpreted as being evidence of retention of function by the stria vascularis and the existence of blood supply to the inner ear in spite of the presence of tumors. Measurement of the EP seems to provide a new tool with which to analyze the causes of hearing loss in acoustic neuromas. Relatively low EP values may suggest mild dysfunction of the stria vascularis with acoustic neuromas.

Aged↗

PubMed1996

Effects of protein kinase C on the Na(+)-H+ exchange in the cochlear outer hair cell.

Two routes, associated with protein kinase C (PKC) and cyclic AMP (cAMP), to regulate the activation of Na(+)-H+ exchange (NHE) were investigated in the outer hair cell (OHC). The intracellular pH (pHi) of OHC loaded with the pHi indicator dye was measured by using fluorescence ratio imaging microscopy. The acid load was carried out by an "NH4Cl pre-pulse". The rate of acid extrusion after an acid load was increased as pHi became more acidic. The linear relationship between the rate of acid extrusion and pHi suggests the presence of an internal modifier site for the H+ ion on the NHE. Although addition of phorbol 12-myristate 13-acetate (TPA) had no effect on pHi in unstimulated conditions, the pHi recovery from an acid load was enhanced by exposure to TPA. This finding can be explained by the pHi dependence of the PKC action, namely, that the activating effect of PKC on the NHE is facilitated by internal acidification. In contrast to the PKC effect, addition of dibutyryl cAMP failed to change the rate of acid extrusion. These findings are consistent with the characteristic property of the NHE-1. Thus, intracellular signal transduction to regulate the activity of the NHE in the OHC involves phosphorylation by PKC.

Animals↗

PubMed1996

[The effect of initial treatment by FP aqueous nasal spray in patients with Japanese cedar pollinosis].

It is well known that an initial treatment with several kinds of antiallergic medicines is useful for patients suffering from Japanese cedar pollinosis to reduce nasal symptoms during the pollen season. Also topical corticosteroids show a preventive effect as antiallergic medicines. In this study, the preventive effect of topical corticosteroids with antiallergic medicine as an initial treatment was evaluated during the 1995 cedar pollen season a season in which a high pollen count was anticipated. Twenty-five patients with cedar pollinosis were selected and divided into two groups. A and B, A topical corticosteroid (fluticasone propionate; Flunase) as well as antiallergic medicine (azelastin) were administered to patients in group A 4 weeks before the beginning of the pollen season. In group B, only antiallergic medicine was given at the same time as group A and a topical corticosteroid was administered after the appearance of the symptoms. Nasal symptoms and mucosal conditions of the nasal cavity were monitored throughout the pollen season. The inflammatory cells in the mucoepithelial layer of the nasal mucosa were also periodically evaluated by immunohistochemical staining. Nasal symptoms and mucosal conditions in group A were significantly improved compared with patients in group B. The infiltration of macrophages in the mucoepithelial layer of the nasal mucosa was strongly inhibited in group A. The numbers of mast cells and EG2-positive cells in group A were not significantly different from those in group B during the pollen season. According to these results, although not all inflammatory cells were inhibited, the initial treatment with Flunase aqueous nasal spray in addition to the conventional initial treatment with antiallergic medicine is very useful for reducing symptoms even in a season with a large amount of cedar pollen.

Administration, Intranasal↗

PubMed1996

[Predictive value of electrogustometry in the preoperative diagnosis of severity of middle ear pathology].

The chorda tympani nerve (CTN) is frequently damaged in various inflammatory middle ear disorders. To determine the validity of electrogustometry in the diagnosis of preoperative severity of a middle ear lesion of the posteosuperior portion of the mesotympanum, the threshold determined by electrogustometry was examined preoperatively and was correlated with the intraoperative findings. One hundred and six ears of 97 patients with various middle ear diseases were examined. The patients ranged in age from 5 to 70 years (average, 39.4) : 55 of them were male and 42 were female. In 80 of them the appearance of the tympanic membrane on the opposite side was normal. The disorders were classified as follows: A : Non-inflammatory diseases including middle ear anomalies, posttraumatic perforation of the tympanic membranes and congenital cholesteatoma without infection (n = 10) ; B : chronic otitis media without cholesteatoma (n = 14) ; C : pars flaccida retraction type cholesteatoma (n = 34) ; D : pars tensa retraction type cholesteatoma and adhesive otitis media (n = 15) ; E : surgically treated ears (n = 33). The average threshold +/- S.D.(dB) of each group according to the above classification was as follows : A : -1.0 +/- 4.4, B : -1.5 +/- 6.2; C : 7.4 +/- 13.7; D : 9.6 +/- 18.2; E : 20.9 +/- 16.8. The rates of abnormal threshold of electrogustometry (more than 8dB) of A, B, C, D and E were 0%, 7.1%, 44.1%, 46.7% and 72.7%, respectively. The intraoperative findings around the CTN were retrospectively classified according to the following 5 groups : I : No pathological tissue was attached to the CTN (n = 44); II : the Granulation tissue or matrix of the cholesteatoma was attached to the CTN (n = 19) ; III : the CTN was surrounded by granulation or a matrix of cholesteatoma (n = 3) ; IV : The CTN was not identifiable due to the severe pathological condition of the middle ear cavity, in either surgically treated or untreated ears (n = 16), V : Surgically treated ears in which the CTN was identifiable (n = 24). The average threshold +/- S.D.(dB) for I, II, III, IV and V were 1.9 +/- 9.6, 2.0 +/- 11.7, 16.0 +/- 20.3, 32.0 +/- 7.4, 16.0 +/- 17.0, respectively. The rates of abnormal threshold of electrogustometry (more than 8dB) of I, II, III, IV and V were 27.3%, 31.6%, 66.7%, 100% and 62.5%, respectively. In both the above classification by the disorders and that by the intraoperative findings around the CTN, differences in the average thresholds between the surgically treated sides and the opposite sides with normally appearing tympanic membranes showed a tendency similar to that of the thresholds of the treated sides. In the present study, the threshold of electrogustometry was correlated with the disease and the intraoperative findings during middle ear surgery, and it was higher in adhesive otitis media and cholesteatoma of the pars tensa type. Electrogustometry is a useful preoperative examination to predict the condition of the posterosuperior portion of the mesotympanum.

Adolescent↗

PubMed1996

[Direct observation of the vibration and the traveling wave on the basilar membrane of the guinea pig].

Basilar membrane vibration was investigated in guinea pigs by using a laser Doppler velocimeter. To monitor the physiological condition of the cochlea, compound action potentials and distortion product otoacoustic emissions were measured before and after each experiment. Sharply tuned (Q10dB : 4.6-7.0) mechanical vibrations were successfully observed in 190 preparations of 15 animals. In these animals, strong compressive nonlinearity of the basilar membrane response and steep phase lag above the characteristic frequency were observed clearly. These findings strongly support the existence of active mechanical elements that play important roles behind the auditory transduction in the cochlea.

Action Potentials↗

PubMed1996

[Effect of aging on distortion product otoacoustic emissions].

The effect of aging on distortion product otoacoustic emissions (DPOAE) was investigated in 58 ears of 32 volunteers with normal hearing DPOAE levels to tones with a fixed frequency ratio (f2/f1 = 1.2) were measured with the CUBDIS system (MIMOSA Acoustics, USA). Age dependency of DPOAE level was clearly observed both in frequency plots (DP-gram) and input-output functions. In elderly persons, DPOAE levels for higher frequency primaries were significantly lower than in younger persons, when no remarkable change of audiometry threshold was noted. These results imply that the DPOAE level can be a sensitive indicator for age-related cochlear dysfunction.

Acoustic Stimulation↗

PubMed1996

The habit of sniffing in nasal diseases as a cause of secretory otitis media.

To clarify the role of habitual sniffing caused by nasal diseases in the pathogenesis of middle ear diseases, 112 pediatric patients with secretory otitis media (183 ears) were examined for associated nasal diseases and habitual sniffing. Middle ear pressure and nasopharyngeal pressure were simultaneously measured during forceful sniffing. Fifty-four percent of the patients with secretory otitis media had allergic rhinitis and/or chronic sinusitis. Sixty percent of the patients with nasal diseases habitually sniffed, whereas only 30.8% of those without nasal diseases had this habit. In the patients with the habit of sniffing, a higher negative pressure tended to be created in the nasopharynx on forceful sniffing than in the patients who did not sniff. Thirty-one of 112 patients (27.7%) were positive on the sniff test. Of these 31 patients, 20 were associated with the habit of sniffing, and in 14 of the 20 patients, nasal diseases were considered to be the primary cause of the habit of sniffing. That is, in 14 of the 112 patients (12.5%) with secretory otitis media, the patients with nasal diseases frequently sniffed and their middle ears were evacuated. This study suggests that in many patients, sniffing provoked by nasal diseases plays an important role in the pathogenesis of secretory otitis media through the creation of negative nasopharyngeal pressure. This mechanism is presumed to be present in approximately one-tenth of pediatric patients with secretory otitis media.

Adolescent↗

PubMed1996

[Congenital cholesteatomas in Japanese--forty from our experience and fifty-five from a survey of the Japanese literature].

To determine the locations of congenital cholesteatomas and to elucidate the relationship between ossicular anomalies and congenital cholesteatomas, cholesteatomas from our patients and those reported in the Japanese literature were investigated. We analyzed 40 ears with congenital cholesteatomas (38 patients) experienced by us during the past 9 years. Our criteria of congenital cholesteatoma were as follows: 1. The tympanic membrane manifests neither retraction, perforation, nor granulation, 2. There is no continuity between the tympanic membrane and the matrix of a cholesteatoma. Twenty patients with past histories of otitis media were included. Thirty-three patients (87%) were males and 2 had bilateral congenital cholesteatomas. The ages of the patients ranged from 2 to 46 years (mean: 10.7). A survey of the Japanese literature revealed 55 additional cases of congenital cholesteatoma reported by others.

Adolescent↗

PubMed1996

Reduced reticulization of palatine tonsils with IgA nephropathy.

Tonsillar abnormalities have been observed in patients with IgA nephropathy (IgAN). In addition, it has been suggested that the reticulization of tonsillar crypt epithelium is important in tonsillar immunity. Therefore, we investigated reticulization of this area in patients with IgAN (10 cases) and compared results with those of control patients who exhibited recurrent tonsillitis or tonsillar hypertrophy (12 cases). Immunohistochemical staining of anti-keratin antibody PKK1 was employed to visualize reticulization. Tonsils of controls showed well developed reticular crypt epithelia with lymphoepithelial symbiosis, and the non-reticulated area was less than 7% (mean 1.9%, range 0-6.3%) of the total crypt epithelia per overall section. In IgAN tonsils, however, non-reticulated crypt epithelium was frequently observed and, in the advanced stage of IgAN, exceeded 50% (mean 62%, range 50-69%) of total crypt epithelia. The extent of glomerular damage in IgAN patients correlated significantly with the percentage of the area of non-reticulated crypt epithelia in palatine tonsils with a correlation coefficient of 0.91. Considering together with our finding that PKK1-positive epithelial reticular cells strongly expressed HLA-DR antigens in normal tonsils, the low level of reticulization in IgAN patients may induce the unusual immunity responsible for the pathogenesis of IgAN.

Adolescent↗

PubMed1995

Treatment of labyrinthine fistula with interruption of the semicircular canals.

Evaluation of postoperative hearing acuity and equilibrium was performed in eight patients with labyrinthine fistula caused by cholesteatoma, in which at least one of the semicircular canals (five cases, lateral; one case, superior; one case, posterior; and one case, both lateral and superior) was interrupted during eradication of the matrix and granulations from the semicircular canals. The interrupted semicircular canals were obliterated firmly with autologous materials such as fascia, perichondrium, bone chips, and cartilage. The observation period ranged from 9 months to 3.3 years. Postoperative hearing was unaltered or improved in seven patients, and decreased by 12 dB in one patient. Postoperative disequilibrium lasting more than 2 weeks was experienced in two patients and disappeared at the second and fifth postoperative months, respectively. Relief from fistula symptoms was complete after surgery, indicating adequacy of this procedure in one-stage open-method tympanoplasty. The present study indicates that manipulation of the semicircular canal with awareness can be conducted without damaging the cochlear function, and that the treatment of labyrinthine fistulas should be performed very carefully but not so conservatively as to lead to future problems. In some cases of deep fistulas of the semicircular canals, interruption and/or obliteration of the semicircular canals can be the most proper procedure.

Adult↗