[Neurogenic inflammation and area of involvement of the facial nerve of the rat]. / Die neurogene Entzündung im Ausbreitungsgebiet des Nervus facialis der Ratte.

Antidromic electrical stimulation of sensory nerves produces vascular hyperpermeability, plasma protein extravasation and oedema. The initial phase of this inflammatory reaction is induced by the release of the neuropeptides CGRP, SP and NKA; the later phase is induced by mast cells. In previous investigations we were able to show that the facial nerve of the rat contains CGRP, SP and NKA as well as mast cells. The same mechanism--increased vascular permeability--plasma extravasation--oedema--is thought to be part of the pathogenesis of Bell's palsy. Hence, we tried to produce neurogenic inflammations in the facial nerves of six adult Wistar rats. To assess plasma extravasation we used Evans blue, a dye which binds to serum albumin, according to the method described by Brokaw and White (1992). Having cut the facial nerve distal of the stylomastoid foramen we induced a neurogenic inflammation by the application of an electrical stimulus to the distal part of the nerve. In comparison to the contralateral, non-stimulated side, we recognized that the inflammatory reactions were limited to the area of the skin innervated by the posterior auricular nerve. So far, we can transfer this "neurogenic inflammation model" the well-known relationship between nerves and inflammatory reactions to this limited area innervated by the facial nerve.

[Blood supply to the facial nerve]. / Untersuchungen zur Durchblutung des Nervus facialis.

At the present time there is no final explanation for the etiology of Bell's palsy. The theory of pathophysiology involving a combined primary and/or secondary ischemia is now well-accepted. As such, it is supposed that there is a dysfunction of the blood vessels which supply the nerve. This is followed by a hyperpermeability and transudation which lead to edema of the nerve and compression of the blood supply. The vicious circle starts and the final result is facial paralysis. The blood supply of the facial nerve has been described previously in the literature, although there have been no experimental investigations on in vivo perfusion of the nerve. In the present study we evaluated the percentage of those vessels perfused among the total blood vessels found in facial nerves of Wistar rats. Animals were examined after i.v.-injections of Evans blue dye, with perfused vessels demonstrable under a fluorescence microscope. Forty-eight hours later, the same tissue section was stained by indirect immunofluorescence and the primary antibody used was directed against myosin of non-muscle sources. This antibody cross-reacted with myosin of vascular endothelial cells and thus allowed identification of any existing blood vessels. More than 90% of the immunostained vessels were labeled with the dye, showing that almost all vessels were perfused.

Innervation of epi- and endoneurial compartments of rat facial, vagus and sciatic nerves as studied by double-labeling immunofluorescence.

The mediators of axon terminals innervating the blood vessels and connective tissue compartments of rat peripheral nerves (facial, vagus and sciatic nerve) were investigated by means of double-labeling immunofluorescence. Sympathetic noradrenergic/neuropeptide-Y-immunoreactive axons innervated epi- and endoneurial arterial blood vessels; noradrenergic fibers without neuropeptide Y immunoreactivity terminated in the endoneurium between the axons of the main nerve trunk. Presumably sensory nerve terminals immunoreactive to substance P/calcitonin gene-related peptide supplied epi- but not endoneurial arteries and arterioles, and ran freely in the endoneurial space. Axons immunoreactive to vasoactive intestinal peptide innervated epineurial blood vessels of the facial and vagus nerve but were absent from the vasa nervorum of the sciatic nerve. The findings are in line with the concept, based upon previous pharmacological experiments, of a tonic constrictory and dilatory innervation of vasa nervorum. However, as judged from the distribution patterns of the neurochemically distinct axonal populations, vascular segments of different connective tissue compartments (epi- versus endoneurial) and body regions (sciatic versus cranial nerves) are differentially addressed by each of these axonal populations. This might have implications for the development of region-specific neuropathies.

[Reconstruction of oral cavity and oropharyngeal defects with a pure muscle-fascia flap]. / Rekonstruktion von Mundhöhlen-und Oropharynxdefekten mit reinen Muskel-Faszien-Lappen.

As a rule carcinomas of the oral cavity and oropharynx are not diagnosed in early stages. Surgical resections of these tumors including margins of safety invariably result in large defects. At present, one-stage flap techniques are preferred for reconstruction, as exemplified by pectoralis major myocutaneous flaps and free revascularized jejunum grafts. The skin island of the myocutaneous flap is underlayed by fat tissue as a sliding surface. Temporary sutures are necessary but have the disadvantage of producing a convex configuration. This shape compromises anatomical reconstruction of the oral cavity and oropharynx. Robertson et al. in 1985 demonstrated an alternative method for a muscle-fascia flap from the pectoralis major muscle. In comparison to the temporalis muscle-fascia flap, the pectoralis muscle-fascia flap is associated with a lesser incidence of complications. Although it is still too early to conclude their definitive use, their application in some cases is now being questioned because of such factors as reduced time of anesthesia.

Immunodiffusion and immunohistochemical investigations on the reactivity of oxide ceramic middle-ear implants.

Oxide ceramic materials (partial and total ossicular replacement prostheses) have been implants of preference for the reconstruction of the ossicular chain because of their excellent biocompatibility. The reaction on the surface of the implants takes place at three biodynamic levels according to the model of Stern's bilayer. We investigated the adsorption of proteins, which is determined by the cellular reaction and degradation to the surface using radial immunodiffusion and immunohistochemical methods. First, ceramic implants of aluminum oxide, hydroxyapatite, glass ceramic and zirconium oxide have individual actual (i.e. biological) surfaces. With a perthometer and the contact-free laser Focodyn method we determined each actual (i.e. biological) surface of the various ceramic implants mentioned above. Using radial immunodiffusion, the adsorption of albumin, glycoprotein, plasminogen, fibronectin, IgA, IgG and IgM shows characteristic rates of adsorption to the respective ceramic surfaces in correlating to the actual surface. A cross-check with fluorescent antibodies confirmed the protein adsorption. The individual surface adsorption of the proteins remains characteristic and is the basis for the recording of cellular reactions after implantation.

Feasibility of proliferation studies using the BrdU and MTT assays with a head and neck carcinoma cell line.

After the failure of interferon monotherapies for head and neck cancer, an increasing number of combination experiments with chemotherapy and interferons have been carried out to improve the antiproliferative effect. In vitro drug testing requires sensitive assay to detect synergistic effects of tested combinations in order not to get false-negative results. The widely used MTT assay (3,4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide) and the BrdU assay 5-bromo-2-deoxyuridine were compared. It could be shown that the BrdU assay is over 10 times more sensitive and that it reflects the cell proliferation status as shown by flow-cytometric analysis using double staining with BrdU. Labeling with BrdU also allows the estimation of the S phase time. Because of the direct effect of interferons on the cell cycle, the BrdU assay could be appropriate for proliferation studies using interferons.

[Neuropeptides in the facial nerve of the rat]. / Neuropeptide im Nervus facialis der Ratte.

The occurrence of peptidergic nerve fibres containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) in the cerebral arteries and arterioles is well known. NPY is a vasoconstrictor, while SP, CGRP and VIP induce cerebrovascular dilatation. Vascular dysregulation of the vasa nervorum of the facial nerve is believed to be a central factor in the pathogenesis of Bell's palsy. Hilger's theory of the primary and/or secondary oedema which is followed by the vicious circle is generally accepted. It was our aim to describe the occurrence and distribution of neuropeptides in the blood vessels of the facial nerve. We examined the facial nerves of 6 male Wistar rats using the indirect immunofluorescence technique. There is not only a characteristic distribution of the neuropeptides in different parts of the facial nerves, but there are also beaded axons of sensory nerve fibers, which are localised freely in the endoneurium. These SP and CGRP containing beaded axons which densely innervate the nerve in the bony canal, are capable of inducing an oedema by neurogenic inflammation. Our findings suggest that there must be a vascular regulation in the facial nerve which is controlled by various neuropeptides.

Improved antiproliferative effect of cisplatin combined with phorbol ester. An in vitro study.

A combination of cisplatin (DDP) and tumor promoter phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) or nonphorboid tumor promoter mezerein (MEZ) were tested by 5-bromo-deoxyuridine (BrdU) and 3,4,5-dimethylthiazol-2,5-disphenyl-tetrazolium bromide (MTT) assays for their antiproliferative actions. DDP and TPA showed a synergistic effect at concentrations where the single drug did not show any significant action. The BrdU assay seemed to be more sensitive than the MTT assay in measuring these drug effects. Epidermal growth factor (EGF)-receptor number and affinity on treated cells were not altered as showed by 125I-EGF-receptor assay. EGF stimulation experiments suggested an inhibition of receptor-mediated signal transduction by TPA.