Cutaneous Angiolymphoid Hyperplasia in a Dog

A 5-year-old male miniature dachshund was presented with a dermal nodule on the left forelimb that increased to 5 mm in diameter over a 2-month period. Grossly, the nodule was firm, and both the external and cut surfaces were homogeneously pale pink in colour. Microscopically, the nodule was comprised of mainly plump endothelial cells and inflammatory cells; among the latter, lymphocytes were predominant, with few scattered plasma cells, mast cells and macrophages. Lymphoid follicles with germinal centres were often observed. Mitotic figures were not observed amongst the endothelial cells. Immunohistochemically, the endothelial cells were positive for vimentin, factor VIII-related antigen and CD31, and the surrounding cells were positive for smooth muscle actin. Lymphocytes expressed CD3 or BLA36. These findings led to a diagnosis of cutaneous angiolymphoid hyperplasia. To the best of our knowledge, this is the first report of a cutaneous proliferative disorder comprising an admixture of proliferating vascular endothelial cells and lymphocytic infiltration with follicle formation in a dog.

Fetal developmental change in topographical relationship between the human lateral pterygoid muscle and buccal nerve

In adults, the lateral pterygoid muscle (LPM) is usually divided into the upper and lower heads, between which the buccal nerve passes. Using sagittal or horizontal sections of 14 fetuses and seven embryos (five specimens at approximately 20-25 weeks; five at 14-16 weeks; four at 8 weeks; seven at 6-7 weeks), we examined the topographical relationship between the LPM and the buccal nerve. In large fetuses later than 15 weeks, the upper head of the LPM was clearly discriminated from the lower head. However, the upper head was much smaller than the lower head in the smaller fetuses. Thus, in the latter, the upper head was better described as an 'anterior slip' extending from the lower head or the major muscle mass to the anterior side of the buccal nerve. The postero-anterior nerve course seemed to be determined by a branch to the temporalis muscle (i.e. the anterior deep temporal nerve). At 8 weeks, the buccal nerve passed through the roof of the small, fan-like LPM. At 6-7 weeks, the LPM anlage was embedded between the temporobuccal nerve trunk and the inferior alveolar nerve. Therefore, parts of the LPM were likely to 'leak' out of slits between the origins of the mandibular nerve branches at 7-8 weeks, and seemed to grow in size during weeks 14-20 and extend anterosuperiorly along the infratemporal surface of the prominently developing greater wing of the sphenoid bone. Consequently, the topographical relationship between the LPM and the buccal nerve appeared to 'change' during fetal development due to delayed development of the upper head.

The dimensions and structural attachments of tip links in mammalian cochlear hair cells and the effects of exposure to different levels of extracellular calcium

The tip links between stereocilia of acousticolateral hair cells have been suggested to contain cadherin 23 (CDH23) comprising an upper branched portion that is bound to a lower portion composed of protocadherin 15 (PCDH15). The molecular conformation of CDH23, its binding to PCDH15, the tip links, and mechanoelectrical transduction have all been shown previously to be sensitive to exposure to low levels of calcium. The aim of this study was to compare the characteristics of tip links in guinea-pig cochlear hair cells with reported features of the CDH23-PCDH15 complex. Tip links were examined using field emission scanning electron microscopy and transmission electron microscopy in conventional preparations and after treatment with the detergent Triton-X-100 or varying calcium concentrations in the extracellular solution. The results showed that tip links have a twisted double-stranded appearance with a branched upper region. They survived demembranation of the stereocilia by detergent suggesting that they have transmembrane domains at both ends. Their lengths, when fixed in the presence of 2 mM extracellular calcium, were approximately 150 nm. With prior exposure to 1 mM calcium their lengths were approximately 164 nm. The lengths in 50 microM calcium are similar ( approximately 185 nm) to those reported for CDH23-PCDH15 complexes in 100 microM calcium ( approximately 180 nm). Exposure to 1 microM calcium caused loss of tip links and an increased distance between the residual attachment sites. The data indicate that extracellular calcium concentration affects tip-link length. One model compatible with the recently proposed tip-link structure is that the CDH23 double strand undergoes calcium-dependent unfolding, changing the length of the links. The bundle may also tilt in the direction of the tallest row of stereocilia as the tip link lengthens and then is lost. Overall, our data are consistent with a tip link composed of complexes of CDH23 and PCDH15 but do not rule out other possibilities.

Differential distribution of beta- and gamma-actin in guinea-pig cochlear sensory and supporting cells

Sensory and supporting cells of the mammalian organ of Corti have cytoskeletons containing beta- and gamma-actin isoforms which have been described as having differing intracellular distributions in chick cochlear hair cells. Here, we have used post-embedding immunogold labelling for beta- and gamma-actin to investigate semiquantitatively how they are distributed in the guinea-pig cochlea and to compare different frequency locations. Amounts of beta-actin decrease and gamma-actin increase in the order, outer pillar cells, inner pillar cells, Deiters' cells and hair cells. There is also more beta-actin and less gamma-actin in outer pillar cells in higher than lower frequency regions. In hair cells, beta-actin is present in the cuticular plate but is more concentrated in the stereocilia, especially in the rootlets and towards the periphery of their shafts; labelling densities for gamma-actin differ less between these locations and it is the predominant isoform of the hair-cell lateral wall. Alignments of immunogold particles suggest beta-actin and gamma-actin form homomeric filaments. These data confirm differential distribution of these actin isoforms in the mammalian cochlea and reveal systematic differences between sensory and supporting cells. Increased expression of beta-actin in outer pillar cells towards the cochlear base may contribute to the greater stiffness of this region.

Clinical results of modified Mitchell's osteotomy for hallux valgus augmented with oblique lesser metatarsal osteotomy

PURPOSE

To evaluate postoperative results of modified Mitchell's osteotomy and its combination with oblique metatarsal osteotomy for the treatment of hallux valgus.

METHODS

A total of 93 feet of 53 patients (2 men and 51 women) with hallux valgus underwent modified Mitchell's osteotomy and were followed up for at least 5 years. Patients' age ranged from 17 to 83 years, and the duration of follow-up ranged from 5 years one month to 18 years 4 months. Modified Mitchell's osteotomy was performed on 53 feet in 31 patients (group A), whereas modified Mitchell's osteotomy augmented with oblique lesser metatarsal osteotomy was performed to the remaining 40 feet in 22 patients (group B). Postoperative results were assessed using a clinical assessment system developed by the Tokyo Medical University based on 5 categories: pain in the first metatarsophalangeal, deformity of the metatarsophalangeal, plantar callosity and/or metatarsalgia of lesser metatarsals, the use of commercially available shoes, and local inflammatory symptoms.

RESULTS

Mean total score improved from 3.8 to 7.9 on a 10-point scale. Scores for 2 categories--plantar callosity and/or metatarsalgia and the use commercially available shoes--were significantly higher in group B at postoperative 5 years. Before surgery, at postoperative 3 weeks, and at postoperative 5 years, respectively, the mean hallux valgus angles were 34.2, 12.0, and 17.1 degrees; mean M1-M2 angles were 16.7, 7.4, and 8.7 degrees; mean M1-M5 angles were 34.9, 25.8, and 26.6 degrees; and mean sesamoid bone shifts were 8.7 mm, 4.3 mm, and 5.9 mm.

CONCLUSION

Modified Mitchell's osteotomy shortens the length of the first metatarsal bone and thus relieves tension in soft tissues such as the adductor hallucis. Nonetheless, the procedure can induce metatarsophalangeal joint malalignment and metatarsalgia, and plantar callosity may develop or persist after surgery. Combining oblique metatarsal osteotomy of the lesser metatarsal bones is useful in patients with uneven metatarsal bone lengths and metatarsophalangeal joint malalignment.

Estrogen-like effect and cytotoxicity of chemical compounds

Luciferase assay, cytotoxicity test and protein quantitative analysis were performed after the exposure of chemical compounds to MVLN cells that are utilized to detect the endocrine disrupting activity. These consequences indicate that the concentration is different between the estrogen receptor mediated proliferation of breast cancer cells and the estrogen receptor mediated transcription by chemical compounds.

Expression of connexin 30 in the developing mouse cochlea

Mutations in the GJB6 gene encoding connexin 30 (Cx30) can cause dominant forms of nonsyndromic deafness. By studying immunohistochemical localization of Cx30 in the mouse cochlea at different ages from 0 to 30 days after birth, we found that the expression of Cx30 is nearly the same as that of Cx26. These findings suggest that as well as Cx26, Cx30 may also contribute to the generation and maturation of endocochlear potential.

Increased von Willebrand factor in the endocardium as a local predisposing factor for thrombogenesis in overloaded human atrial appendage

OBJECTIVES

We investigated immunoreactive von Willebrand factor (vWF), a platelet adhesion molecule, in the endocardial endothelium and its relationship to thrombogenesis in the human atrial appendage.

BACKGROUND

Intra-atrial thrombogenesis is generally thought to be induced by blood stasis in the atrial appendage involved with atrial fibrillation (AF). Little attention has been paid to alterations of the endocardial endothelium on which the thrombus develops.

METHODS

Atrial appendage tissue was obtained at heart surgery or at autopsy from AF and non-AF cardiac patients and from noncardiac patients. Immunohistochemistry for endothelial cell markers including vWF, CD31, CD34 and endothelial nitric oxide synthase (eNOS) and platelet glycoprotein Ib/IX or IIb/IIIa was performed and semiquantitatively graded.

RESULTS

In contrast to the apparent immunostaining for CD31, CD34 and eNOS, only focal or little immunoreactive vWF was seen in the endocardium of noncardiac patients. Immunoreactive vWF in the endocardial endothelium was increased in most cardiac patients, particularly in the left, but not in the right, atrial appendage of patients with mitral valvular disease, irrespective of whether AF was present. Platelet adhesion/thrombus formation in the endocardium was found in limited sites in which the overlying endothelium was deficient in eNOS and CD34. When warfarin-treated cases were excluded, there was a significant correlation between the immunohistochemical grade for vWF and the degree of platelet adhesion/thrombus formation in the endocardium.

CONCLUSIONS

Immunoreactive vWF in the endocardial endothelium was increased in overloaded human atrial appendage, which may be a local predisposing factor for intraatrial thrombogenesis.

Expression of the Sox10 gene during mouse inner ear development

Mutations in the SOX10 gene, encoding a cell-lineage specific transcription factor, are associated with congenital deafness. We analyzed the expression of Sox10 mRNA in developing mouse inner ear by in situ hybridization. Sox10 mRNA is expressed in the entire epithelia of the otic vesicle at embryonic day 11.5 (E11.5) and in the developing cochlea and vestibule at E13.5. In postnatal day 8 and adult cochleas, Sox10 expression is restricted to the supporting cells of the organ of Corti. These expression profiles suggest that Sox10 is important for development of the cochlea.

Expression of connexin 31 in the developing mouse cochlea

Connexin 31 (Cx31) mutations cause an autosomal dominant form of high-frequency hearing loss. The immunohistochemical localization of Cx31 in mouse cochlea was studied at different ages between 0 and 60 days after birth (DAB). Cx31-like immunoreactivity was detected in fibrocytes of spiral ligament and spiral limbus at 12 DAB, gradually enhanced with the increase of age and reached the adult pattern on 60 DAB. Immunoreactivity decreased gradually from the basal to apical turn in all developmental stages. The mRNA of Cx31 was also identified by RT-PCR. The distribution of Cx31 and connexin 26 were obviously different in the developing mouse cochlea. The expression and distribution of Cx31 in the development may explain the progressive hearing loss in human Cx31 mutations.

Expression of connexin 26 and Na,K-ATPase in the developing mouse cochlear lateral wall: functional implications

The immunohistochemical localization of connexin 26 (a gap junction protein) and Na,K-ATPase in the mouse cochlear lateral wall was studied at different ages between 0 and 30 days after birth (DAB). Connexin 26-like immunoreactivity was sparsely distributed among the connective tissue cells just lateral to the future marginal cells of the stria vascularis on 0 DAB. In the mice of 3-6 DAB, connexin 26 was observed in the strial basal cell area, and was increased in its distribution density on 10 DAB. Connexin 26 was sparsely distributed among the fibrocytes in the spiral ligament and the suprastrial zone on 10 DAB, and its distribution density increased rapidly in the mouse on 12 DAB. The immunohistochemical distribution reached the adult pattern in the cochlear lateral wall on 15 DAB. Weak Na, K-ATPase-like immunoreactivity was observed in the epithelial cells, corresponding to the future strial marginal cells, on 0 DAB. Its staining intensity was enhanced with the increase of age, and reached the adult pattern on 10 DAB. In contrast, Na,K-ATPase-like immunoreactivity in the type II fibrocytes and suprastrial fibrocytes was first detected on 12 DAB, and reached the mature level on 15 DAB. It is well known that the endolymphatic potential (EP) reaches the adult level 2 weeks after birth. The expression patterns of connexin 26 and Na,K-ATPase in the fibrocytes of the spiral ligament and the suprastrial zone coincided with the rapid growth and maturation of EP. These findings may suggest a role for the gap junctional communications and Na,K-ATPase activity of the fibrocytes within the cochlear lateral wall in the generation and maturation of EP.

Altered cochlear fibrocytes in a mouse model of DFN3 nonsyndromic deafness

DFN3, an X chromosome-linked nonsyndromic mixed deafness, is caused by mutations in the BRN-4 gene, which encodes a POU transcription factor. Brn-4-deficient mice were created and found to exhibit profound deafness. No gross morphological changes were observed in the conductive ossicles or cochlea, although there was a dramatic reduction in endocochlear potential. Electron microscopy revealed severe ultrastructural alterations in cochlear spiral ligament fibrocytes. The findings suggest that these fibrocytes, which are mesenchymal in origin and for which a role in potassium ion homeostasis has been postulated, may play a critical role in auditory function.

Density of motility-related charge in the outer hair cell of the guinea pig is inversely related to best frequency

Whole cell voltage clamp and freeze fracture were used to study the electrophysiological and ultrastructural correlates of the outer hair cell (OHC) lateral membrane molecular motors. We find that specific voltage-dependent capacitance, which derives from motility-related charge movement, increases as cell length decreases. This increasing non-linear charge density predicts a corresponding increase in sensor-motor density. However, while OHC lateral membrane particle density increases, a quantitative correspondence is absent. Thus, the presumed equivalence of particle and motor is questionable. The data more importantly indicate that whereas the voltage driving OHC motility, i.e. the receptor potential, may decrease with frequency due to the OHC's low-pass membrane filter, the electrical energy (Q x V) supplied to the lateral membrane will tend to remain stable. This conservation of energy delivery is likely crucial for the function of the cochlear amplifier at high frequencies.

Acute effects of combined administration of kanamycin and furosemide on the stria vascularis studied by distortion product otoacoustic emission and transmission electron microscopy

Acute effects of kanamycin and/or furosemide administration on the stria vascularis of the guinea pig cochlea were assessed by distortion product otoacoustic emission (DPOAE) and transmission electron microscopy. Kanamycin alone failed to affect the DPOAE levels and ultrastructural changes. Furosemide alone caused a rapid but reversible fall of the DPOAE levels. No remarkable pathological changes in the strial vascularis were observed after a complete recovery of the DPOAEs. On the other hand, furosemide injection following kanamycin with a 2 hour interval resulted in two patterns of significant changes in the DPOAEs, namely, a sudden drop in the DPOAE levels 2 to 3 hours after furosemide injection and a gradual fall in the DPOAE levels immediately after the incomplete recovery from the furosemide-induced decrease of the DPOAE levels. Ultrastructural changes in the stria vascularis included numerous vacuoles in the strial marginal cells and increased electron density of the intermediate and basal cells. These physiological and morphological changes in the stria vascularis may imply new ototoxic features induced by kanamycin potentiated by furosemide.

[Myelodysplastic syndrome (RAEB in T) developed in a renal allograft recipient]

A 46-year-old man who had been treated with azathioprine (150 mg/day) and prednisolone (7.5-10 mg/day) for 16 years after allogeneic renal transplantation was admitted to our hospital in July 1996 for evaluation of pancytopenia. Three years earlier he had been given a diagnosis of renal pelvic and ureteral cancer, and underwent left nephrectomy with total uretectomy. His bone marrow was normocellular with excess of blasts (27.6%), and displayed trilineage myelodysplasia. A chromosomal analysis of the bone marrow revealed 43-45, XY with del (1) (p13), -5, del (7) (q22), -17, -18, and -19. The patient was given a diagnosis of refractory anemia with excess of blasts in transformation (RAEB in T), and treated with idarubicin and cytosine arabinoside. Two months later, overt acute leukemia developed and reinduction chemotherpay was started, but the patient died of cerebral hemorrhage in October. This case suggests that immunosuppressive agents such as azathioprine might play an important role in the pathogenesis of MDS (RAEB in T) and renal pelvic and ureteral cancer after renal transplantation.

The usefulness of computed tomography in the diagnosis of impacted fish bones in the oesophagus

The usefulness of computed tomography (CT) in the diagnosis of fish bone impaction in the oesophagus was evaluated. Thirty-two patients were examined by plain X-ray followed by direct oesophagoscopy for suspected fish bone impaction. Among 25 cases in which fish bones were actually removed, foreign bodies were not clearly demonstrated by plain X-ray in 14 cases (56 per cent). Eleven cases underwent CT prior to the oesophagoscopic examination. Fish bones were clearly demonstrated by CT in all patients. CT also clearly visualized secondarily-induced inflammatory changes in the neighbouring structures. In order to confirm this result, we made a simulation model of oesophageal fish bone impaction, using fish bones of three different species surrounded by a water bag. In comparison with plain X-ray, CT depicted a superior image of fine fish bones and provides extremely useful information for the management of impacted fish bones in the oesophagus.

Ultrastructural localization of cadherin in the adult guinea-pig organ of Corti

The apices of the majority of cells of the organ of Corti are connected together by junctional complexes to form the reticular lamina, a barrier that prevents the mixing of endolymph and perilymph. These complexes include tight junctions, adherens junctions and desmosomes. Further information is required about the identity and distribution of the molecules involved in these connections if the function and organization of the reticular lamina are to be well understood. One major category of molecules occurring in adherens junctions and desmosomes, and involved in the maintenance of tissue integrity, is the cadherins. However, although cadherin has been identified in junctions between supporting cells in the adult mammalian organ of Corti at the light microscopic level, its ultrastructural distribution has not so far been described. A post-embedding immunogold labelling technique has therefore been used in conjunction with a monoclonal antibody to cadherin to investigate its ultrastructural distribution in the adult guinea-pig reticular lamina. Immunolabelling is observed in hair cell-supporting cell junctions and in supporting cell-supporting cell junctions. In addition, there is more labelling associated with inner hair cell-supporting cell junctions than with outer hair cell-supporting cell junctions. This may indicate that the junctions associated with the two types of hair cell have different functional properties.

Restoration of the mucociliary clearance of the maxillary sinus after endoscopic sinus surgery

BACKGROUND

Whether endoscopic sinus surgery (ESS) restores the mucociliary clearance of the maxillary sinus needs further evaluation.

METHODS

We evaluated the mucociliary clearance of the maxillary sinus by using a radionuclide technique in 12 patients with chronic sinusitis (sinusitis group) and in six patients who had undergone ESS 6 to 14 months after the surgery (post-ESS group). The mucosal cilia taken from the maxillary sinus in 12 patients with sinusitis before and after ESS (paired experiments) were examined by light and electron microscopy.

RESULTS

The radionuclide placed endoscopically in the maxillary sinus in eight patients immediately after ESS maintained 81.2 +/- 16.3% of its radioactivity after 30 minutes. This result was consistent with results in four patients with untreated chronic sinusitis in whom the radionuclide had been instilled by antral puncture (86.9% +/- 3.5%). On the other hand, in six patients in the post-ESS group the radionucleotide maintained only 25.9% +/- 11.6% of its radioactivity, demonstrating statistically significant differences from those of both the sinusitis group without ESS (p < 0.005) and the group 4 days after ESS (p < 0.005). The absence of the cilia in the sinusitis condition was recognized in 35.5% +/- 12.1% (n = 12) of the epithelial cells. On the other hand, the absence of cilia was significantly (p < 0.01) reduced to 5.3% +/- 3.7% of the epithelial cells in the post-ESS condition. Electron microscopic observation also revealed abnormal cilia in the sinusitis condition, whereas the mucosal cilia were regularly arranged in the post-ESS condition.

CONCLUSIONS

The mucociliary clearance of the maxillary sinus disturbed by chronic inflammation was restored by ESS, indicating the clinical effectiveness of ESS for the treatment of chronic sinusitis.

Long-term nitrate treatment increases cardiac events in patients with healed myocardial infarction. Secondary Prevention Group

BACKGROUND

Nitrates dilate coronary arteries, ameliorate myocardial ischemia, minimize left ventricular remodeling, and reduce mortality in patients with acute myocardial infarction. However, the effects of long-term treatment with nitrates on cardiac events in patients with healed myocardial infarction are not known.

METHODS AND RESULTS

A total of 1,002 patients with healed myocardial infarction (789 male and 213 female) were randomly divided into 2 groups: treatment with nitrates or nontreatment. The mean observation period was 18.0 +/- 19.9 months. Primary end points were nonfatal and fatal recurrent myocardial infarction, death from congestive heart failure, and sudden death. Baseline characteristics of the 2 groups were also compared to determine any effects on outcome. Among the 621 cases treated with nitrates, 41 cases (6.6%) experienced cardiac events during the observation period, whereas only 12 of the 381 cases that were not treated with nitrates (3.1%) had cardiac events. This difference was statistically significant (p < 0.05; odds ratio 2.17; 95% confidence interval 1.13-4.19). There were no differences in the incidence of noncardiac death or being lost to follow-up between the 2 groups. Although the precise mechanism of this increase in the occurrence of cardiac events by long-term treatment with nitrates is not clear, nitrate tolerance with possible rebound and neurohormonal effects may be involved.

CONCLUSION

Long-term treatment with nitrates increased cardiac events in patients with healed myocardial infarction.

Immunohistochemical localization of Gnathostoma spinigerum larval antigens by monoclonal antibodies: II. Electron microscopy

Immunocytochemical localization of antigens in advanced third-stage larvae of Gnathostoma spinigerum (GsAL3) was studied by immunogold labeling method using seven G. spinigerum specific monoclonal antibodies (MAbs), FS-3D11, SS-5H5, SK-6C4, SK-4E1, SK-7G6, SK-8D4 and SA-9B5. All these MAbs belong to the IgG1 subclass and only FS-3D11 and SS-5H5 recognize carbohydrate epitopes. The paraformaldehyde-fixed GsAL3 were embedded in Lowicryl K4M medium, and the gold colloidal particles used were 15 nm in size. When the worm sections were probed with FS-3D11, the gold particles appeared to concentrate specifically on the intestinal brush border. When SS-5H5 was applied, the particles were scattered densely over the brush border and in the cytoplasm of epithelial cells. The rest of the MAbs which recognize protein determinants exhibited a lack of labeling. The results suggested that the carbohydrate antigenic determinants recognized by the two MAbs are the most stable and most abundant particularly in the intestine of GsAL3. These results also confirmed the previous finding that the most antigenic site of GsAL3 is the intestine.

Development of an advanced Kirkpatrick-Baez microscope

We have developed an advanced Kirkpartrick-Baez (AKB) x-ray microscope to diagnose laser-produced plasmas. The AKB microscope is composed of two pairs of hyperbolic and elliptic mirrors to avoid spherical aberration and field obliquity. The spatial response of the microscope has been measured by x-ray backlighting a fine grid with laser-plasma x rays. A spatial resolution of better than 3 microm has been obtained with 2.5-keV x rays over the field of 800 microm at a magnification of 25. This microscope has been applied for laser implosion experiments, resulting in high-resolution images of the compressed cores.

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.

Immunoreactivity of sensory hair bundles of the guinea-pig cochlea to antibodies against elastin and keratan sulphate

The stereociliary bundles of hair cells contain cross-linking extracellular filaments which have been suggested to play a role in mechanoelectrical transduction. To investigate the composition of these filaments, antibodies to the extracellular matrix molecules elastin and keratan sulphate have been used for light- and electron-microscopic immunocytochemistry of the guinea-pig organ of Corti. With the antibody to elastin, no immunoreactivity was found in hair bundles. This implies either that the epitope recognised by this antibody is not present in the links or that it is obscured. The antibody to keratan sulphate labelled the stereociliary bundles of both inner and outer hair cells but not supporting cells. The tips of the tallest stereocilia, especially on outer hair cells, the tips of the shorter stereocilia where the tip links attach to the stereociliary membrane, and the attachments of the lateral links, were labelled. This suggests that the links contain keratan sulphate proteoglycans, molecules which in other tissues are known to maintain structural integrity and fibrillar spacing, and to influence the microenvironment of the cell surface.

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.

Carbohydrate distribution in the living utricular macula of the guinea pig detected by lectins

Carbohydrate distribution in the fresh utricular macula of the guinea pig was analysed using lectins such as Concanavalin A (ConA), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), soybean agglutinin (SBA), Ulex europeus agglutinin (UEA-1) and wheat germ agglutinin (WGA) by means of confocal laser scanning microscopy. The ciliary bundle was strongly reactive to ConA, PNA, SBA and WGA but not to DBA and UEA-I, showing that the ciliary bundle has abundant D-galactose (GaI), N-acetyl-D-glucosamine (GlcNAc), D-mannose (Man) and sialic acid(s) (Sia) but not detectable amounts of L-fucose (Fuc) and terminal N-acetyl-D-galactosamine (GalNAc). Similar patterns of lectin bindings with moderate-to-weak intensities were observed on the non-cilial apical surface, on the surface of the otoconia and in the gelatinous layer of the otoconial membrane. On the contrary, the globular substance, a precursor of the otoconia, was scarcely reactive to any lectin examined, implying that it lacks glycoconjugates on its surface. Previous histochemical studies reported that the otoconial membrane possesses a much higher affinity for lectins that does the sensory epithelium (including the cilia) in the vestibular organ. This discrepancy suggests that factors in the preparation process may affect the otoconial membrane or the surface coat of the cilia to change their lectin affinity. Meanwhile, sialidase treatment augmented the affinity of the ciliary bundle for DBA and PNA, indicating that sialylated GalNAc and Gal are present on the vestibular ciliary bundle.

ATP-induced increase in intracellular Ca2+ concentration in the cultured marginal cell of the stria vascularis of guinea-pigs

The primary culture of marginal cells from the explant of the stria vascularis of guinea-pigs was established and confirmed by morphological, immunohistochemical and physiological characters of the cultivated cells. The positive stain of cytokeratin 18 without vimentin and desmin expressions indicated the epithelial origin of the cultured polygonal cells. Electron microscopical findings of cultured cells resembled the morphological characteristics of marginal cells. The addition of 100 microM ouabain to the cultured cells significantly increased the intracellular Na+ concentration, providing the evidence for the presence of Na+ pump. Using the cultured marginal cells identified by the above-mentioned findings, the effects of neurotransmitters and hormones in regulating intracellular Ca2+ concentration ([Ca2+]i) were investigated. The addition of 10(-4) M ATP caused an increase in [Ca2+]i, which was independent of the presence of extracellular Ca2+. The rank order of agonist potency was ATP > alpha, beta-methylene ATP > ADP. Adenosine, however, evoked no response. Cultured marginal cells may possess P2-purinergic receptors which mobilize Ca2+ from the intracellular Ca2+ pool.

Isolation of acini from nasal glands of the guinea-pig

A procedure for isolating the acinar cells of the serous gland in the mammalian nasal septum has been developed. This technique is characterized by meticulous and selective isolation with minimal contamination by the surface epithelial cells and employs enzymatic treatment with collagenase. The isolated cells were confirmed to be serous gland acini as shown by negative staining with Alcian blue and a high electron density of the granules. The acini were more than 90% viable as judged by trypan blue exclusion. Ultrastructural integrity of the cells was well maintained following the isolation procedure. Application of acetylcholine to the isolated acini induced an inward current in a whole-cell patch clamp and increased intracellular Ca2+ concentration measured by fura-2. These acetylcholine responses were completely blocked by atropine. These physiological findings directly demonstrated that nasal gland acini possess muscarinic-activated receptors as previously suggested. These isolated cells hold promise for the in vitro study of secretory mechanisms in the mammalian nasal gland.

Fine structure of the lamina basilaris of guinea pig cochlea

The lamina basilaris of guinea pig cochlea was studied with SEM after trypsin treatment, and with TEM of resin sections and deep-etching replicas. The lamina consists of radial, evenly compacted filaments in the zona arcuata, and radial, discretely bundled filaments in the zona pectinata. In both zones, elementary filaments measured about 12 nm in thickness on the replica. The filaments formed more or less irregular passing bridges with each other and, eventually, a three-dimensional network which was continuous with the basement membrane under the supporting cells.

Microtubules of guinea pig cochlear epithelial cells

By tannic acid staining, the 13-protofilament composition of cochlear hair cell microtubules, an impressive contrast against the 15-protofilament microtubules in cochlear pillar cells, was verified. The 15-protofilament microtubules formed a large and stiff cytoskeletal bundle in pillar cell bodies involving abundant actin filaments. The bundles were always situated vertically, i.e., longitudinally to the cell body axis, and were most numerous in the outer as well as the inner pillar cells in the basal turn, decreasing gradually toward the apex. Such gradient architecture of the pillar cell cytoskeleton can be correlated with the tuning mechanism for traveling waves of sound containing variable frequencies.