In the first experiment, newborn female rats were treated with 0.005 mu g or 0.02 mu g interleukin-16 (IL) twice daily from Day 1-4 of life. These rats were allowed to grow up until 300 days of age. The second layer of the entorhinal region of the gyrus parahippocampalis at the level of the amygdaloid nucleus was investigated morphometrically for density of cells, i.e. density of neurons and density of glial cells. Furthermore, the area and the circumference of these cells were measured. In the second layer, a dose-dependent decrease of cell number was observed, caused by a decrease of all kinds of cells. The size of nuclei of neurons of the IL-treated animals was increased in a dose-dependent manner. In a second experiment, pregnant animals were injected with 0.02 mu g IL twice daily from Day 17 until 21 of pregnancy. Female offspring were also allowed to grow up until 300 days of age. In the second layer of the entorhinal region a tendency of reduction of cell density was also found. In the third experiment, the second layer of the entorhinal region of female and male rats, which were treated with 0.02 mu g IL from Day 1-4 of life was investigated immediately after cessation of treatment. In the second layer of the entorhinal region the number of cells was again found to be decreased, however, caused only by reduction of the number of neurons. Density of glial cells was increased Size of neurons of these animals was decreased. Prenatal IL-exposure at the beginning of the period of critical brain differentiation in rats appears to lead to a long lasting reduction of density of cells in the second layer of the entorhinal region. Early postnatal IL-exposure results in comparable, but still more pronounced alterations in this region. Human subjects with functional psychoses also exhibit a decreased number of cells in this brain area.

The stimulation of the proximal auditory nerve or the Cochlear Nuclear Complex (CNC) situated in the lateral recess of the fourth ventricle is a possibility of hearing rehabilitation for patients suffering from bilateral deafness by bilateral cerebellopontine-angle tumors or by transsections of cochlear nerves on both sides. Using such anatomical landmarks as proximal cochlear nerve, flocculus, choroid plexus and taenia the surgeon can locate exactly the CNC for this stimulation. We investigated location, diameter and surrounding structures of the CNC on 10 human brains fixed in 10% formalin-solution and on 9 histological series of these subjects.

The stimulation of the proximal auditory nerve or the Cochlear Nuclear Complex (CNC) situated in the lateral recess of the fourth ventricle is a possibility of hearing rehabilitation for patients suffering from bilateral deafness by bilateral cerebellopontine-angle tumors or by transsections of cochlear nerves on both sides. Using such anatomical landmarks as proximal cochlear nerv, flocculus, choroid plexus and taenia the surgeon can locate exactly the CNC for this stimulation. We investigated location, diameter and surrounding structures of the CNC on 10 human brains fixed in 10% formalin-solution and on 9 histological series of these subjects.

The suboccipital (retrosigmoid) and the middle fossa routes are recommended for preservation of hearing in surgery for acoustic neuroma. We carried out a comparative study of the critical distances and bony landmarks on 520 petrous bones. Unlike the transtemporal route, the suboccipital approach offers no landmarks for identification of the common crus, the vestibule or the facial nerve; the lateral portion of the internal auditory canal is not always seen. The fundus can be seen in only 50% of bones without opening the labyrinth.

Epithelium changes caused by wearing of tissue-borne prosthesis were established on the basis of tissue specimens, taken away from the palate of 22 corpses with own teeth and 18 edentulous corpses with removable prosthesis. The epithelium height of the denture supporting area was reduced especially in the lateral and ventral cuts. The papillary body was significantly reduced.

On the basis of the morphological evidences of 22 adults with own teeth and 18 denture wearers a significant reduction of the thickness and the number of layers of the stratum granulosum could be established under dentures.

After a 180 day lasting period of observation a persistent chronical inflammation occurred in the implants surrounding tissue of rats implanted with simple sintered biovitroceramics, where as the same material, coated with dental ceramic did not result in a comparable tissue reaction. After application of these coated implants we obtained a significant diminished formation of the periimplant connective tissue capsule. Inactivation of surfaces, being into contact with soft tissue, mentioned above, could be an economical, easy handling method.

The material exploration for implants close in also histological study of bone-proofs after implantation in test animals. For light microscopical utilization of implant-bone-polishings was developed a new method of colouring what shows a better distinction between types of tissue around the implant and a time economizing of 3 h.

Implant bone specimen of inert materials and of the material BVK Ap 40 mended histologically. The bone specimen were both decalcified and carried to the polish technique after plastics embedding. The experiments were carried out in miniature swines (type Mini-Lewe) and rabbits. Microscopical and polarisation optical investigations were carried out. A connective-tissue membrane was provable at the interface implant-bone in all cases with use of the biocompatible material titanium. With BVK Ap 40 was observed a direct compound with the bone.