Per-Gotthard Lundquist

Morphological Basis of Directional Sensitivity of the Outer Hair Cells in the Organ of Corti

Electron‐microscope studies of cross sections of hair bundles on the outer hair cells in the organ of Corti show a consistent orientation of the sensory hairs. In the cuticle, a basal body is regularly found on the side of the cell toward the Hensens cells. The sensory hairs are organized in the shape of w pointing towards the basal body. The morphological polarization of the hair cells in the organ of Corti is discussed in the light of similar polarization of the hair cells in the vestibular sensory epithelia and the lateral‐line canal organs. A close relation is to be found between the morphological and electrophysiological polarization of the mechanoreceptors in the sense organs of hearing and equilibrium.

Kanamycin-induced changes in cochlear hair cells of the guinea pig

SummaryElectron-microscopical studies on the organ of Corti in kanamycin-intoxicated guinea pigs showed that progressive changes occurred in the cochlear hair cells. The changes appeared first in the basal turn of the organ of Corti, and affected primarily the outer hair-cells. During the later stages of intoxication, degeneration spread from the basal turn upwards, in the direction of the apex of the cochlea and, finally, affected all the external hair-cells.The early changes caused clumping of the chromatin in the nucleus, swelling of the nuclear membrane, damage in the mitochondria, with vesiculation of the mitochondrial cristae, and the formation of lamellated structures. The lysosomes were converted into dense bodies exhibiting various degeneration patterns. The ribosomes disappeared at an early stage from the cytoplasm.Even in cells where severe changes had occurred the hairs and cuticle seemed to be intact.During the final stages the plasma membrane, as well as the hairs and cuticle, was destroyed, and only remnants of these structures remained.Even after the disappearance of the sensory cells and the afferent nerve endings, some efferent nerve endings were still present in the organ of Corti.The action of kanamycin seems to differ slightly from that of streptomycin, since the changes caused by kanamycin in the plasma membrane are a fairly late effect, whereas the earliest changes occur apparently in the RNA protein-synthesis system and in the mitochondria of the external hair-cells.ZusammenfassungElektronenmikroskopische Untersuchungen am Cortischen Organ von Meerschweinchen mit Kanamycinintoxikation ergaben eine fortschreitende Schädigung der cochlearen Haarzellen. Die Veränderungen begannen in der basalen Schneckenwindung und betrafen vorwiegend die äußeren Haarzellen. In späteren Intoxikationsstadien breitete sich die Degeneration von der Basalwindung nach aufwärts bis in die Schneckenspitze aus und wurde schließlich an allen äußeren Haarzellen gesehen.Die früheren Veränderungen manifestierten sich am Kern mit Chromatinverklumpung, Schwellen der Kernmembran, Schädigung der Mitochondrion mit vesikulären Cristae mitochondriales und Bildung von Lamellenstrukturen. Die Lysosomen waren in dichte Körper verwandelt und wiesen verschiedene Degenerationsmuster auf. Die Ribosomen verschwanden früh aus dem Cytoplasma. Sogar in schwer geschädigten Zellen erschienen Haare und Cuticula intakt.In den Endstadien waren Plasmamembran, Haare und Cuticula bis auf Reste zerstört. Einige efferente Nervenendigungen waren selbst nach dem Verschwinden der Haarzellen und der afferenten Endigungen noch anzutreffen.Die Wirkung von Kanamycin ist offenbar etwas anders als die von Streptomycin, da die Veränderungen an der Plasmamembran ziemlich spät auftreten, während sich die frühesten Schäden im System der RNA-Proteinsynthese und in den Mitochondrien der äußeren Haarzellen zu manifestieren scheinen.

Sensory hair fusion in vestibular sensory cells after gentamycin exposure

SummaryScanning and transmission electron microscopic studies were performed on the crista ampullaris epithelium of gentamycin treated guinea pigs. 200 μl of a 0.3% solution of the antibiotic was injected once a day through a polythene tube into the middle ear. After seven daily injections various stages of sensory hair degeneration could be observed on the crista surface. The central part of the crista was most severely damaged whereas the periphery of the sides of the crista, as well as the area close to the planum semilunatum, showed less change. The sensory cells of type I were more severely damaged than those of type II. The sensory hairs showed successive stages of fusion. Initially multiple points of contact between neighbouring sensory hairs appeared. Later the plasma membrane disappeared at the points of contact and protoplasmic bridges were formed between the hairs. These bridges increased in length and width until a complete fusion occured between two or more neighbouring hairs. Thus giant hairs were formed. The fusion started close to the cuticle and progressed distally. Balloon-shaped protrusions were then formed into which protoplasm containing cell organelles damaged, to varying extent, was pushed out from the cell. Finally the sensory cell disintegrated and disappeared.ZusammenfassungRaster- und transmissionselektronenmikroskopische Untersuchungen wurden am Epithel der Crista ampullaris von Meerschweinchen, die mit Gentamycin behandelt wurden, durchgeführt. 200 μl einer 0,3%igen Lösung des Antibioticums waxen jeweils durch einen Polyäthylentubus in das Mittelohr injiziert worden. Nach 7 täglichen Injektionen konnten verschiedene Stufen von Sinneshaar-degenerationen auf der Oberfläche der Crista beobachtet werden. Der zentrale Teil der Christa war am schwersten geschädigt, während die Peripherie der Seiten und auch die Gegend, die dem Planum semilunatum benachbart ist, geringere Veränderungen zeigte. Die Sinneszellen vom Typ I waxen schwerer geschadigt als die vom Typ II. Die Sinneszellen zeigten schrittweise Stadien der Verschmelzung. Anfangs erschienen multiple Kontaktpunkte. Später verschwand die Plasmamembran an diesen Koutaktpunkten und Protoplasmabrücken bildeten sich zwischen den Haaren. Diese Brüeken nahmen an Länge und Breite zu bis zu einer kompletten Verschmelzung zwischen zwei oder mehr benachbarten Haaren. So wurden „Riesenhaare” gebildet. Die Verschmelzung begann in der Nähe der Cuticula und schritt distalwärts fort. Dann kam es zu ballonähnlichen Ausstülpungen, in welchen Protoplasma mit zerstörten Zellorganellen verschiedener Ausdehnung von der Zelle her ausgestoßen wurden. Schließlich löste sich die Sinneszelle aus dem Verband und verschwand.

Elektronenmikroskopie am sensorischen Apparat der Fadenhaare auf den Cerci der Schabe Periplaneta americana

SummaryThe filiform hairs are sensitive for week air currents. Each receptor unit consists of an elastically inserted cuticular hair, a single sensory cell, and a surrounding fluid filled cavity lined partly by the cuticle and partly by special lining cells, exhibiting many villiform protrusions. The mentioned cavity — at least by adult cockroaches — is extracellular and the authors suggest the nomenclature “receptorlymph cavity”. The expression “vacuole of the trichogen cell” should not be used.The distal process of the sensory cell protrudes into the base of the cuticular hair and contains a tubular body consisting of more than 1000 microtubuli which, in the resting position of the hair, are slightly bent.It is suggested that the stimulus is transmitted to the tubular body, where bending of the tubuli causes depolarization and straigthening repolarization, when bending the hair in opposite directions.

Early postmortem changes in the Organ of Corti (guinea pig)

SummaryEarly post mortem changes in the Organ of Corti are described. 15 minutes after death, when kept at room temperature, 20° C (63° F), an oedematous swelling is observed within the cytoplasm of hair cells and nerve endings, the latter being more severe affected. After 30 minutes post mortem the mitochondria of the hair cells have also become significantly swollen. Three hours post mortem the general character of the hair cells is still recognizable, but most of the nerve endings have been completely destroyed.

Hypernephroma metastasis in the pituitary gland

ZusammenfassungBei einem 59jährigen Mann mit einem Hypernephrom der rechten Niere wurde eine Metastase dieses Tumors in der Hypophyse, 9 Jahre nach dem Auftreten des Primärtumors festgestellt. Außerdem wurde eine Metastase in der linken Niere gefunden. Demzufolge kann nicht sicher gesagt werden, ob die Metastase in der Hypophyse vom Primärtumor der rechten Niere oder von der später erkrankten linken Niere herrührt. Unseres Wissens wurde bisher noch nicht über eine Metastase in der Hypophyse, ausgehend von einem Hypernephrom, berichtet.SummaryIn a 59-year-old man with a hypernephroma tumour of the right kidney, a metastasis in the pituitary gland of this neoplasm was diagnosed 9 years after removal of the kidney. However, metastases were also found in the left kidney. It cannot be established whether the metastasis in the pituitary gland came from the original tumour or from the other diseased kidney. To the best of our knowledge, a hypernephroma metastasis to the pituitary gland has not been reported previously.

Combined preoperative radiotherapy and surgery in the treatment of carcinoma of the anterior two-thirds of the tongue†

Sixty‐three patients with squamous cell carcinoma of the anterior two‐thirds of the tongue were treated with preoperative external radiotherapy (mean target dose 42.60 Gray or 4260 rad) and surgery. The expected 5‐year survival, expressed as life table estimate of percent of survivors, was 77% for patients with Stage I tumors, 69% with Stage II, and 13% for patients with tumors in Stages III‐IV (p < 0.001). Fourteen patients experienced local recurrences, 7 had homolateral neck metastases, 4 had contralateral neck metastases and 3 had distant metastases. In 15 cases no cancer could be detected at review of the surgical specimens, but 2 of these died of their cancers. In 43 cases cancer was present in the specimens, and 26 of these died of their cancer (p < 0.01).

Destruction and Regeneration of Jawbone after Cryogenic Application An Experimental Study

On 13 rabbits part of the lateral aspect of the jawbone was frozen with liquid nitrogen in two sessions. The animals were sacrificed 2, 4, 12, and 24 weeks after the cryosurgery. The specimens were analyzed with microangiography according to the Spalteholz technique and with light microscopy. The whole width of the lateral cortex, measuring around 3 mm, was subject to bone destruction two weeks after cryosurgery. New bone formation, on the other hand, was evident in the frozen area and on the undamaged periosteum some distance from the lesion. The same area, 12 weeks after the injury, was completely restored. Bone destruction and regeneration are discussed with special reference to the vascular response to the injury.

Balloon embolization of the sphenopalatine artery in a case of a juvenile angiofibroma

SummaryIn a case of juvenile nasopharyngeal angiofibroma a peroperative transarterial embolization of the main feeding artery was used to minimize blood loss during surgery. Embolization and surgical technique as well as morphological tumor aspects are discussed.