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Biomedical subjects

M Anniko

Publications and source records attributed to M Anniko.

At least 37 records · Page 2Linked to original sources
PubMed1998

Appearance and distribution of two Ca2+-binding proteins during development of the cochlea in the musk shrew.

In the developing cochlea of the musk shrew, Suncus murinus, the localization of two Ca2+-binding protein, calbindin and calmodulin, which are thought to play different roles in the nervous system, was examined during gestational and postpartum periods. Calbindin is thought to play a Ca2+ buffering role, while calmodulin activates other proteins. Cochleae from the musk shrews sacrificed from gestational day (GD) 15 to postnatal day (PP) 9 and as adults, were immunohistochemically analyzed. The localization and order of appearance of calmodulin in sensorineural elements were similar to those of calbindin, except for timing of appearance. Calmodulin-staining was recognized first in the spiral ganglion neurons on GD21, followed by the inner hair cells (IHCs) on GD23 and outer hair cells (OHCs) on GD26, while calbindin immunoreactivity in the spiral ganglion neurons on GD19, the IHCs on GD21 and the OHCs on GD23. In hair cells, during development, immunostaining of calbindin and calmodulin was initially seen in the cytoplasm, followed by the cuticular plate. Cytoplasmic staining then decreased in mature hair cells. Non-sensorineural components also showed positivity for both calbindin and calmodulin. The lateral wall of the cochlear duct was positive for calbindin, while the stria vascularis was positive for calmodulin. Immunoreactivity for calbindin was present earlier than that of calmodulin in sensorineural elements, suggesting that in the developing cochlea, calbindin and calmodulin have different functions and that Ca2+ buffering capacity, which is regulated by Ca2+ buffer proteins, such as calbindin, may be required before trigger proteins, such as calmodulin, function.

Aging↗
PubMed1998

Programmed cell death in the development of the mouse external auditory canal.

Programmed cell death (PCD) is an essential event for development. The purpose of this work was to ascertain how PCD, in vivo designated apoptosis, is involved in the development of the external auditory canal. We performed a time sequence study of the distribution of apoptosis during the development of external auditory canal (EAC) of the mouse. ICR mice ranging in age from embryonic day 11.5 (E11.5) to 12 days after birth (DAB) were used in the present study. A part of each head including both ears was removed and was processed according to its purpose. Light and electron microscopy for morphological studies and TUNEL method (Gavrieli et al. [1992] J Cell Biol., 119:493-501) for histochemical studies were used. On E11.5, distinct TUNEL-positive staining occurred in the branchial arch. Between E15.5 and 1DAB, TUNEL-positive cells were observed throughout the EAC and the number of these cells decreased with age. On E15.5 and E16.5, numerous TUNEL-positive cells were observed in a cavity remained in the epithelial plate. Transmission electron microscopy revealed that these cells had the features of apoptosis. From 3-12 DAB, no apoptosis was observed in the EAC except for the terminal differentiation of the skin of the EAC. Apoptosis was not observed during recanalization of the EAC, but occurred during the formation of the epithelial plate. The investigation established that PCD is involved in the formation of the epithelial plate, whereas only cornification of the epithelium of the EAC is associated with recanalization.

Animals↗
PubMed1998

Lipopolysaccharide-induced expression of nitric oxide synthase II in the guinea pig vestibular end organ.

The purpose of the investigation was to ascertain whether inoculation of bacterial lipopolysaccharide (LPS) into the vestibular organ of the guinea pig might induce formation of nitric oxide synthase (NOS) II. Forty-eight hours after the animals were injected with 1 mg transtympanic LPS, varying degrees of impaired caloric responses were observed with similar degeneration of vestibular hair cells. These effects could be blocked with N-nitro-L-arginine methylester, a competitive inhibitor of NOS. Findings suggested that NOS II, which was not normally detectable in the guinea pig vestibular organ but was present following inoculation of LPS, produced the nitric oxide as the toxic factor causing cell damage. If true, LPS may represent a reproducible method for studying the vestibular pathogenesis of inner ear disease.

Animals↗
PubMed1998

Acute effects of semicircular canal destruction on the cochlea, with and without preceding Pseudomonas aeruginosa exotoxin A treatment.

Acute electrophysiological and morphological changes in the cochlea following destruction of the semicircular canals (SCCs) were investigated to elucidate differences in cochlear vulnerability to surgical procedure under two conditions: normal healthy condition and a pathological condition induced by Pseudomonas aeruginosa exotoxin A (PaExoA). Frequency-specific auditory brainstem response recording and examination by light microscopy (LM) and scanning electron microscopy (SEM) were performed in the acute stage, immediately following, and 2, 5, and 10 days after the intervention. All normal healthy rats showed noticeable hearing loss immediately after the operation, predominantly in lower frequency areas, followed by complete recovery within 5 days. LM revealed rupture and slight distension of Reissner's membrane. SEM revealed considerable disarray of the stereocilia, especially on the outer hair cells (OHCs) of the third row in the upper half-turns of the cochlea. By contrast, all rats under pathological conditions showed delayed and incomplete hearing recovery from postoperative hearing loss. LM revealed various kinds of cochlear reaction, such as distension of Reissner's membrane, infiltration of inflammatory cells into the cochlea, and severe inflammatory change. Damage both of inner hair cells in the basal turn and of OHCs in the upper half-turns was more noticeable, compared with that under normal conditions. These findings indicate that SCC destruction under pathological conditions induced by PaExoA is detrimental to postoperative hearing recovery, even if the preoperative hearing level had appeared electrophysiologically normal.

ADP Ribose Transferases↗
PubMed1998

Image analysis of the human inner ear.

The KS 300 is a multifunctional software image analysis system using an object-oriented programming environment. The possibility of its application for the inner ear was studied by using specimens from humans and squirrel monkeys, immunostained for the brain-derived calcium-binding protein, S-100 protein. Grey images were used for measurements. The cell borders were outlined by hand, using a digitizer. The absolute grey values of the pixels changed when the brightness of the images or other conditions changed. By contrast, the relative grey values, i.e. the absolute grey values correlated to the mean grey values of the histoimage, remained constant. By utilizing these relative grey values, it was possible to compare cells both between different specimens and between different areas within the same specimen. The different grey values of spiral ganglion cells stained for S-100 protein are objective quantitative measurements and are believed to reflect differences in their function. In some regions of both human and squirrel monkey specimens, relatively intensely stained cells predominated, whereas in other regions, relatively weakly stained cells were mainly observed. Thus, our image analysis system using the relative grey values has proved suitable for quantitative analysis of immunostained specimens in order to compare them and to assess cell function.

Adult↗
PubMed1998

Programmed cell death in the developing epithelium of the mouse inner ear.

Programmed cell death is as essential to development as is proliferation. Thus, the objective of this study was to elucidate the spatiotemporal involvement of programmed cell death in the development of the inner ear epithelia. Programmed cell death is seen in situ as apoptosis. A time-sequence study was performed on the distribution of apoptosis during the development of the inner ear epithelia of the mouse using the TdT-mediated dUTP-biotin nick labeling (TUNEL) method to detect apoptosis histochemically. Apoptosis occurred during the early stages of development of the inner ear and took place earlier in the organs of equilibrium than in the cochlea. These periods corresponded to those of active proliferation of epithelial cells in the inner ear. Since cell-cell interactions change after the removal of neighboring cells by apoptosis, apoptosis may influence cytodifferentiation.

Animals↗
PubMed1997

Developmental morphology of the middle ear.

The development of the murine middle ear was monitored both qualitatively and morphometrically by scanning electron microscopy from the 19th gestational day to the adult stage. At birth, the middle ear was less well developed than the inner ear. The tympanic membrane (TM) was obscured by occlusion of the external auditory canal. Ciliated cells and secretory granules were present in the middle ear epithelium already 5 days after birth (DAB). Keratin debris was discerned on the external layer of the TM 9 DAB. By 12 DAB, mesenchymal tissue had resorbed from the middle ear cavity, except around the upper part of the ossicles. The middle ear was immature at birth but developed rapidly until 12 DAB. When compared with the avian middle ear the mouse middle ear was basically similar to that of humans, although in the human the stapedial artery is vestigial whereas in the mouse it persists as an important vessel. In man, there is no orbicular apophysis and no gonial of the malleus. The hypotympanum of the human middle ear is less developed than that of the murine middle ear. The mouse external auditory canal matures postnatally until 12 DAB, while in humans its development is complete at birth.

Animals↗
PubMed1997

Auditory epithelial migration. III: An immunohistologic study using anti-BrdU antibody on tympanic membrane in mouse.

A localization pattern of epidermal cells on the tympanic membrane (TM) and their migratory patterns were studied in mice, by means of immunohistologic technique using an anti-bromodeoxyuridine (BrdU) antibody. The BrdU was instilled intraperitoneally and the animals were painlessly sacrificed between 1 hour and 10 days after the injection. An immunostaining technique using anti-BrdU antibodies was applied on whole mount TM tissues. One hour after injection, BrdU-labeled cells were found in the handle of the malleus (HM) region and in the annular region of the pars tensa of the TM. Some labeled cells were observed in the intermediate region of the upper half of the superior quadrant, but no labeled cells were found in the remaining part of the intermediate region. Labeled cells were also evident in the pars flaccida without any particular pattern of distribution. As time elapsed after the injection, the labeled cells first appearing in the HM region had migrated laterally and inferiorly from the HM toward the annulus, while those in the annular region had considerably decreased in number. Results of the present study are the following: 1) the proliferation center of epidermal cells in the pars tensa is located in two different areas, i.e., the HM region and annular region, 2) newly generated cells in the HM region migrated from the HM region toward the annular region, whereas those in the annular region migrate from the the annular region to the external auditory canal, and 3) no specific generation center is located in the pars flaccida. On the basis of these results, we discuss the relationship between the site of the proliferation center of epidermal cells and their migratory patterns.

Animals↗
PubMed1997

Electrophysiological effects of multiple instillation of Haemophilus influenzae type b endotoxin on the inner ear.

An analysis of auditory brainstem response (ABR) thresholds and ABR-based frequency tuning curves was performed in 15 Sprague-Dawley rats exposed to Haemophilus influenzae type b endotoxin; 5 microg/50 microl toxin was instilled every second day, altogether five times, into the middle ear cavity through a small perforation in the tympanic membrane. ABR was measured 48 h after the second application and 24 h, 48 h, 5 days and 10 days after the fifth instillation. Five applications of toxin had no statistical effect on ABR thresholds and no changes in TC configuration were observed. It is concluded that Haemophilus influenzae type b endotoxin, instilled repeatedly through the tympanic membrane into the middle ear, does not affect cochlear electrophysiology.

Animals↗
PubMed1997

Cochlear changes following destruction of semicircular canal in healthy and previously toxin-exposed rats. An electrophysiological and morphological investigation.

One group of Sprague-Dawley rats (group A, n = 6) was treated by instilling Pseudomonas aeruginosa exotoxin A (PaExoA), and another (group B, n = 6) treated similarly with Haemophilus influenzae type b endotoxin (HiBEndo). In group A a 20 dB hearing loss was observed, predominantly in the high-frequency region, which was reversible within 1 month. In group B no significant hearing impairment was noted. Between 1 and 6 months later, the lateral and posterior semicircular canals (SCCs) were ablated unilaterally. Control rats (group C, n = 8) were subjected to ablation only. All rats were cochleotomized contralaterally prior to labyrinthine surgery. Frequency-specific evoked potential testing at 2-31.5 kHz tone bursts was performed before and directly after surgery, 6, 24 and 48 hours and 1, 4 and 16 weeks postoperatively. After surgery in 18 rats, thresholds rose immediately, predominantly at 2, 4 and 6 kHz, followed by varying degrees of recovery. Greatest immediate postoperative hearing loss was observed in group A; no rat recovered completely and two rats showed severe permanent threshold elevation. All group B rats recovered completely, except one showing moderate threshold impairment. No permanent hearing loss was observed in group C. This study shows that destruction of SCCs in rats does not necessarily cause permanent hearing loss, even if the fluid spaces are not sealed off. However, previous exposure of the middle ear to PaExoA (but not HiBEndo) renders the cochlea more vulnerable and can result in persistent hearing loss.

Animals↗
PubMed1997

Effect of Pseudomonas aeruginosa exotoxin A on inner ear function.

Electrophysiological changes were studied in the albino rat following instillation of Pseudomonas aeruginosa exotoxin A into the middle ear cavity through the tympanic membrane. Hearing threshold was measured by a burst-elicited, frequency-specific auditory brainstem response (ABR) technique prior to exposure, then 24 and 48 h, 5 days, 2 and 4 weeks after the toxin instillation. A single dose (1 microgram/20 microliters) of Pseudomonas aeruginosa exotoxin A raised the ABR threshold over the whole frequency range, by 5-25 dB, particularly in the high tones. All threshold shifts were of combined conductive and cochlear type, reversible, with deterioration starting at 24-48 h and recovery at 2-4 weeks. Effusion of serous fluid occurred at 24 or 48 h, resulting in conductive hearing loss. Latency/intensity curves revealed a cochlear component in addition to conductive hearing loss. Morphological examination by SEM showed slight and inconsistent derangement of OHCs. It is concluded that Pseudomonas aeruginosa exotoxin A causes middle ear inflammation, facilitating penetration to the inner ear and that this toxin also reversibly affects cochlear function.

ADP Ribose Transferases↗
PubMed1997

Auditory epidermal cell migration. VII. Antigen expression of proliferating cell nuclear antigens, PCNA and Ki-67 in human tympanic membrane and external auditory canal.

A location of proliferating cells was investigated in eight human normal tympanic membranes (TMs) and external auditory canals (EACs) by an immunohistochemical method using two different types of antibodies for nuclear antigens in proliferating cells: anti-PCNA monoclonal antibody, and anti-Ki-67 polyclonal antibody. Four specimens prepared for cryostat sections were immunostained by both antibodies. Another four were fixed in 4% formaldehyde solution, embedded in paraffin wax and were reacted only with anti-PCNA antibodies. The expression pattern of Ki-67 was basically the same as of PCNA. In the pars tensa (PT), immunoreactivities were expressed in the nuclei of basal layer cells and cells just overlying the basal layer of epidermis both in the handle of the malleus (HM) and annular regions. In the intermediate region of the PT, no immunoreactivity was found basically, apart from a few labelled cells observed in the upper-third of the superior quadrant. In the pars flaccida (PF) and in both the osseous and cartilaginous regions of the EAC, positive cells were also situated in the basal layer and the deeper aspect of the suprabasal layers without any specific distributing pattern. It was certified that the generation centre of epidermal cells (keratinocytes) in the PT was located in both the HM and annular regions, and that stem cells in the PF and the EAC were uniformly scattered in the basal layer and the deeper aspect of the spinous layer. According to these findings, the migratory patterns of auditory epidermal cells in the human TM and EAC were discussed.

Antibodies, Monoclonal↗
PubMed1996

Morphological changes in rat submandibular gland mucous cells during fixation with 10% formalin.

The features of mucous cells in 10% formalin (FA)-fixed submandibular glands differ markedly from those fixed in glutaraldehyde (GA). We therefore studied morphological changes in mucous cells during 10% FA fixation. Mucous cells were fixed in either 10% FA, neutral sodium-phosphate-buffered (Na-PBed) 10% FA, ice-cold 10% FA or an ice-cold fixative mixture of 2.0% paraformaldehyde (PA) and 0.5% GA. Two different methods were used: immersion fixation and venous perfusion fixation. The 10% FA-fixed tissues had elliptical or flattened nuclei, a clear cytoplasm and no secretory granules. Tissues fixed with the fixative mixture displayed almost round nuclei, a broad endoplasmic reticulum and abundant secretory granules in the cytoplasm. Tissues immersion-fixed with neutral Na-PBed 10% FA or perfusion-fixed with ice-cold 10% FA had almost the same light microscopic appearance as that of the mixture-fixed tissues. To elucidate the process of morphological changes during 10% FA fixation at room temperature, samples immersed in 10% FA for varying periods of time were postfixed immediately in the fixative mixture and exposed to microwave irradiation. This method produced a variety of findings, even within the same section. There was a significant difference in the findings seen in the center of the section and at the periphery. The initial changes caused by 10% FA were rupture of the secretory granules located in the perinuclear region and destruction of the perinuclear organelles such as Golgi apparatus, mitochondria and endoplasmic reticulum. Absorption of the endoplasmic reticulum progressed so that the perinuclear region became translucent. To obtain a better structure in mucous cells from the fixed submandibular gland tissues, an appropriate fixative such as GA should be used and the fixative should infiltrate into the tissues as quickly as possible.

Animals↗
PubMed1996

Auditory epithelial migration: I. Macroscopic evidence of migration and pathways in rat.

Auditory epithelial migration (AEM) was studied in the rat for up to 42 days following the application of dye on the tympanic membrane (TM) and external auditory canal (EAC). Migratory pathways were similar to those in the human. In the pars tensa (PT), pathways were radially and centrifugally oriented from the handle of the malleus (HM) toward the annulus. However, the pathway along the HM from the umbo to the pars flaccida (PF), as reported in the human, was not observed in the rat; instead, a shallow downward pathway along the HM. In the PF, the radial spread of dye-markings from the proximal part of the HM to the upper wall of the EAC, as found in the human, was also observed in the rat. We conclude that the TM and EAC of the rat constitute an appropriate experimental model with which to study the human type of AEM.

Animals↗
PubMed1996

The effect of gentamicin on cytoskeletons in the vestibular sensory cells: a high-resolution scanning electron microscopic investigation.

The effect of gentamicin on the cytoskeletal organization of guniea pig vestibular sensory cells was investigated employing the saponin perfusion method and scanning electron microscopy. The intermediate filaments and microtubules were noted to have degenerated following gentamicin intoxication. Such degeneration was not linked with primary mitochondrial damage, but closely related to subsequent degeneration of Golgi apparatus and of endoplasmic reticulum. These findings suggest that microtubules and intermediate filaments work closely together to maintain the structural integrity of both the Golgi apparatus and the membrane-bound organelles, which can be altered by ototoxic drugs before the degeneration of membrane-bound organelles.

Animals↗
PubMed1996

Auditory epithelial migration. II: Morphological evidence for auditory epidermal cell migration in rat.

Morphology of the tympanic membrane (TM) and external auditory canal (EAC) was studied in healthy, intact rat ears. TM-perforated ears (3 days after making the perforation) and TM-perforation-healed ears (14, 28 and 42 days after making the perforation). In intact ears, the epidermis in the annular region of the EAC displayed a characteristic appearance with cytoplasmic protrusions. We termed these protrusions as "finger-like projections". In contrast to the rat, the annular region of the EAC in the guinea-pig did not show "finger-like projections". Following a perforation in the centre of the anterior or the posterior quadrant of the pars tensa in rats the "finger-like projections" disappeared from the annular region on the perforated side of the EAC, while the projections remained on the malleus side of the perforation edge. In perforation-healed ears analysed 42 days after the perforation, the "finger-like projections" had recurred in the annular region on the perforated side of the EAC. The "finger-like projections" are likely to express maturation (keratinization) and desquamation of epidermal cells in the pars tensa and also could constitute morphological evidence of their migration on the TM.

Animals↗
PubMed1995

Cytoskeletal proteins in human hair cells.

Human cochlear and vestibular hair cells (HCs) were analysed for the three major cytoskeletal types of structures: microfilaments, microtubules, and intermediate filaments and several of their associated proteins. Specific immunomorphological features were identified: the apical surface, the infracuticular rod of F-actin, the cytoplasm and the HC bases and their interactions with adjacent supporting cells. There is morphological evidence for at least three functionally interacting units: the OHC as a cytoskeletal string interacting with the Deiter's cell, being a part of the rigid pancellular protein shell of the organ of Corti; compartmentalization of HCs (surrounded by rigid intermediate filament proteins in the supporting cells); and a calcium-guided short-loop feed-back control of type I HCs. The cytoskeletal composition of all four types of human HCs and their adjacent structures is similar to, although not identical with, corresponding compositions in other mammalian species.

Actins↗