Jan Wersäll

Incidence of oral carcinoma in patients with leukoplakia of the oral mucosa

A series of 782 patients with a clinical diagnosis of oral or lip leukoplakia was followed with regular checks for 1 to 44 years (mean 12 years). Oral carcinoma developed in 2.4% of the patients in 10 years and in 4% in 20 years. The prevalence in the various age groups was about 50 to 100 times greater than for the Swedish population according to the 1959 Cancer Registry. It was primarily the small group of cases of leukoplakia in persons not using tobacco that were responsible for the excess morbidity from oral carcinoma; among tobacco users with leukoplakia the figure was considerably lower. There is no evidence the the incidence of oral carcinoma can be diminished by surgical removal of the leukoplakia but this does not mean that the operation should be abandoned, mainly for histologic diagnosis. The prevalence of other malignant tumors than oral and lip carcinoma in cases of oral leukoplakia did not differ from that of malignant tumors in the Swedish population as a whole.

SITE OF ACTION OF STREPTOMYCIN UPON INNER EAR SENSORY CELLS.

The effects of streptomycin on the inner ear sensory epithelia were studied in guinea pigs by means of the electron microscope. The most severe damage was found in the vestibular sensory cells starting with degeneration of, and myelin figure formation in, the mitochondria. Later, swelling appeared in the sensory hairs with deformation of the cell surface, and finally disappearance of the sensory hairs, swelling of the cell surface, often with rupture and ejection of cells and cell debris into the endolymph. Nerve fibers and nerve endings were unchanged. The organ of Corti was less extensively damaged. Changes were confined to the mitochondria and stereocilia of the hair cells. The damage of the sensory cells was explained as an affection mainly of the plasma membrane of the cell and the membrane component of the mitochondria with inhibition of the formation of the rigid component of the membranes and damage to the permeability barrier.

STRUCTURE AND INNERVATION OF THE SENSORY EPITHELIA OF THE LABYRINTH IN THE THORNBACK RAY (RAJA CLAVATA).

A description is given of the general architecture of the sensory epithelia of the labyrinth of the elasmobranch fish Raja clavata, including an electron-microscopic study of the ultrastructural organization of the sensory hair cells and their hair processes, as well as of the supporting cells. The innervation of the hair cells and the associated synaptic structures are also described. The hair cells are found to be of uniform shape and cytological appearance. However, there exists a pronounced dimorphism so far as the sensory hair processes are concerned. These consist in each cell of a varying number of stereocilia with which a single kinocilium is associated. This has the typical structure of a cilium with 9 + 2 longitudinal filaments. Two widely different diameters of stereocilium are encountered in neighbouring hair cells, and it is suggested that this may point to a fundamental dimorphism among the sensory cells. The topographic arrangement of the kinocilia appears to be of functional significance and it is postulated that their position within each hair bundle is related to the direction of excitatory and inhibitory displacement of the hair bundle in the course of mechanical stimulation of the sensory cell. This situation is explored and analyzed for all sensory epithelia of the labyrinth, and the findings are related to what is known about their mode of function. The root structures of the kinocilia are described and it is shown that they, too, appear to be functionally polarized. Each supporting cell bears a single rod-like hair process which resembles the kinocilia in so far as it has at least 9 longitudinal filaments, but differs from it in certain aspects of its root structure. The question of the functional significance of this ciliary rod is discussed. Three types of nerve endings are found. They differ in the size and cytoplasmic contents of their terminal structure and are described as non-granular, granular, and small electrondense nerve endings. Whether the third type resembles the ending of an independent nerve supply cannot be decided.

A Quantitative Analysis of the Afferent Innervation of the Organ of Corti in Guinea Pig

A quantitative analysis of the afferent innervation of the organ of Corti was made on normal and vestibular nerve-sectioned guinea pigs. Section of the vestibular nerve at the internal auditory meatus provided an efficient means of eliminating the efferent innervation to the cochlea without significant loss of afferent fibres. Nerve counts on normal and de-efferented animals revealed that about 10-15 % of the cochlear afferent innervation supplies the outer hair cells. The remaining 85-90% of afferent fibres innervate the inner hair cells. As in cats, all tunnel spiral bundle fibres and upper tunnel crossing fibres were efferent to outer hair cells. Since unmyelinated fibres in the osseous spiral bundle were not counted, quantitative analysis of the efferent innervation to inner hair cells could not be made. However, a significant loss of myelinated fibres in the osseous spiral lamina after vestibular nerve section confirms that many myelinated efferent fibres are present in this region.

Ultrastructure of an electroreceptor (mormyromast) in a mormyrid fish, Gnathonemus petersii. II.

Light and electron microscopic observations on the type B organ (mormyromast) of the lateral line complex of mormyrids reveal the existence of two types of sensory cells each with distinct separate innervation. The type A cell is specific for this organ whereas the type B cell is almost identical with that of the tuberous organs of mormyrids. The type A cells are located at the base of an intradermal jelly sphere. The type B cells are found within a separate sensory chamber connected to the jelly sphere with a small duct. The type B censory cells are attached to a highly differentiated accessory platform in which three types of accessory cells can be distinguished. The morphological data suggest that the type B organ can provide, by two channels, sensory informations concerned with the same external event, i.e., can detect two different parameters of the same external stimulus.

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.

The Ultrastructure Of The Afferent Synapse On Hair Cells In The Frog Labyrinth

The fine structure of the synaptic contact between sensory cells and afferent nerve terminals of ampullar crista of the frog (Rana temporaria) is described. The specializations of this synapse, including synaptic vesicles, and membrane-related structures, show certain differences according to the fixation and contrasting methods used. Parts of these structures are thought to contain proteins which probably are specific for mediating transmitter from the sensory cell to the afferent nerve ending. The mechanism of the synaptic transmission is discussed and thought to be of neuro-chemical type.

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.

Experimental Studies on the Nerve–Sensory Cell Relationship during Degeneration and Regeneration in Ampullar Nerves of the Frog Labyrinth

The degeneration and regeneration of afferent and efferent nerves to the crista ampullaris in the frog were studied after transsection of the ampullar nerves. In some experiments one or both rostral ampullar nerves were simply divided and left in place. In other experiments the ampullar nerves to the horizontal and to the anterior vertical crista were divided and the branch to the former was brought into contact with the distal stump of the anterior vertical ampullar nerve. Sensory cells in the labyrinth survived total denervation for 1-2 weeks without regular signs of ultrastructural damage. The afferent synaptic structures in these cells were often preserved in the denervated stage. The afferent nerve fibres degenerated earlier than the efferent ones. Both type of fibres reinnervated the vestibular epithelium after division of the ampullar nerve. The fibres from a horizontal ampullar nerve could reinnervate a denervated anterior vertical crista, resulting in misdirected reflexes. About 40 days after division both function and morphological organization had been restored to normal.

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.